[
    {
        "anchor": "Wilson loop distributions, higher representations and centre dominance\n  in SU(2): To help understand the centre dominance picture of confinement, we look at\nWilson loop distributions in pure SU(2) lattice gauge theory. A strong coupling\napproximation for the distribution is developed to use for comparisons. We\nperform a Fourier expansion of the distribution: centre dominance here\ncorresponds to suppression of odd terms beyond the first. The Fourier terms\ncorrespond to SU(2) representations; hence Casimir scaling behaviour leads to\ncentre dominance. We examine the positive plaquette model, where only thick\nvortices are present. We show that a simple picture of random, non-interacting\ncentre vortices gives a string tension about 3/4 of the measured value.\nFinally, we attempt to limit confusion about the adjoint representation.",
        "positive": "Confinement Physics and Topology in QCD: Based on the dual-superconductor picture, we study the confinement physics in\nQCD in terms of the monopole in the maximally abelian (MA) gauge using the\nSU(2) lattice QCD. In the MA gauge, the off-diagonal gluon component is forced\nto be small, and hence microscopic abelian dominance on the link variable is\nobserved in the lattice QCD for the whole region of $\\beta$. From the\ngluon-propagator analysis in the lattice QCD, the origin of abelian dominance\nfor the long-range physics is interpreted as the effective mass $m_{ch} \\simeq\n0.9 {\\rm GeV}$ of the charged gluon induced by the MA gauge fixing. In the MA\ngauge, there appears the macroscopic network of the monopole world-line\ncovering the whole system, which would be identified as monopole condensation\nat a large scale. Using the dual Wilson loop in the MA gauge, we find the\neffective mass of the dual gluon field, $m_B \\simeq $0.5GeV, which is the\nevidence of the dual Higgs mechanism by monopole condensation. The large\nfluctuation of off-diagonal gluons remains around the monopole in the MA gauge,\nand this charged-gluon rich region would provide the effective monopole size as\nthe critical scale of the abelian projected QCD. Instantons are expected to\nappear in the charged-gluon rich region around the monopole world-line in the\nMA gauge, which leads to the local correlation between monopoles and\ninstantons."
    },
    {
        "anchor": "On the Schroedinger functional in QCD: In a series of publications [\\ref{LNWW},\\ref{Schroedinger}], L\\\"uscher et al.\nhave demonstrated the usefulness of the Schr\\\"odinger functional in pure SU(2)\nand SU(3) gauge theory. In this paper, it is shown how their formalism can be\nextended to include fermions. In the framework of Wilson's lattice QCD, we\ndefine the Schr\\\"odinger functional by making use of the transfer matrix\nformalism. Boundary conditions for the fermions arise naturally. We then take\nthe naive continuum limit of the action and show that no lattice peculiarities\nare left over. The corresponding free Dirac operator has a unique self-adjoint\nextension with purely discrete spectrum and no zero modes.",
        "positive": "Effect of Multiple Higgs Fields on the Phase Structure of the\n  SU(2)-Higgs Model: The SU(2)-Higgs model, with a single Higgs field in the fundamental\nrepresentation and a quartic self-interaction, has a Higgs region and a\nconfinement region which are analytically connected in the parameter space of\nthe theory; these regions thus represent a single phase. The effect of multiple\nHiggs fields on this phase structure is examined via Monte Carlo lattice\nsimulations. For the case of N>=2 identical Higgs fields, there is no remaining\nanalytic connection between the Higgs and confinement regions, at least when\nLagrangian terms that directly couple different Higgs flavours are omitted. An\nexplanation of this result in terms of enhancement from overlapping phase\ntransitions is explored for N=2 by introducing an asymmetry in the hopping\nparameters of the Higgs fields. It is found that an enhancement of the phase\ntransitions can still occur for a moderate (10%) asymmetry in the resulting\nhopping parameters."
    },
    {
        "anchor": "Critical properties of 3D Z(N) lattice gauge theories at finite\n  temperature: The phase structure of three-dimensional Z(N>4) lattice gauge theories at\nfinite temperature is investigated. Using the dual formulation of the models\nand a cluster algorithm we locate the critical points of the two transitions,\ndetermine various critical indices and compute average action and specific\nheat. Results are consistent with two transitions of infinite order, belonging\nto the universality class of two-dimensional Z(N) vector spin models.",
        "positive": "Twisted Boundary Conditions in Lattice Simulations: By imposing twisted boundary conditions on quark fields it is possible to\naccess components of momenta other than integer multiples of 2pi/L on a lattice\nwith spatial volume L^3. We use Chiral Perturbation Theory to study\nfinite-volume effects with twisted boundary conditions for quantities without\nfinal-state interactions, such as meson masses, decay constants and\nsemileptonic form factors, and confirm that they remain exponentially small\nwith the volume. We show that this is also the case for \"partially twisted\"\nboundary conditions, in which (some of) the valence quarks satisfy twisted\nboundary conditions but the sea quarks satisfy periodic boundary conditions.\nThis observation implies that it is not necessary to generate new gluon\nconfigurations for every choice of the twist angle, making the method much more\npracticable. For K->pipi decays we show that the breaking of isospin symmetry\nby the twisted boundary conditions implies that the amplitudes cannot be\ndetermined in general (on this point we disagree with a recent claim)."
    },
    {
        "anchor": "Continuum limit of baryon-baryon scattering with SU(3) flavor symmetry: We report a study of the scattering of two octet baryons using lattice QCD.\nThe baryon-baryon spectrum is computed using distillation on eight lattice\nensembles spanning six lattice spacings and multiple volumes, all at the SU(3)\nflavor symmetric point with $m_\\pi=m_K\\approx 420$ MeV. Using finite-volume\nquantization conditions, we determine the scattering phase shift and the\npresence of bound states. Focusing on the $H$ dibaryon, our results show large\ndiscretization effects: in the continuum, the binding energy is\n$B_H=4.56\\pm1.13\\pm0.63$ MeV, whereas on our coarsest lattice spacing this is\nlarger by a factor of about 7.5. We also present preliminary results for a\n$D$-wave phase shift and for the spectrum in the nucleon-nucleon ${}^1S_0$\nchannel.",
        "positive": "Simulation of dynamical (u,d,s,c) domain-wall/overlap quarks at the\n  physical point: We perform hybrid Monte-Carlo simulation of $N_f=2+1+1 $ lattice QCD with\ndomain-wall quarks at the physical point. The simulation is carried out on the\n$ L^3 \\times T = 64^3 \\times 64 $ lattice with lattice spacing $a \\sim 0.064 $\nfm ($ L > 4 $ fm, and $ M_\\pi L > 3 $), using the Nvidia DGX-1 (8 V100 GPUs\ninterconnected by the NVLink). To attain the maximal chiral symmetry for a\nfinite extent ($N_s=16$) in the fifth dimension, we use the optimal domain-wall\nfermion for the quark action, together with the exact one-flavor action for\ndomain-wall fermion. We outline the salient features of our simulation (without\ntopology freezing, and small residual mass), together with the preliminary\nresult of the masses of $ \\pi^\\pm $, $ K^\\pm $, and $ D^\\pm $."
    },
    {
        "anchor": "Gauge theory of Lorentz group as a source of the dynamical electroweak\n  symmetry breaking: We consider the gauge theory of Lorentz group coupled in a nonminimal way to\nfermions. We suggest the hypothesis that the given theory may exist in the\nphase with broken chiral symmetry and without confinement. The lattice\ndiscretization of the model is described. This unusual strongly coupled theory\nmay appear to be the source of the dynamical electroweak symmetry breaking.\nNamely, in this theory all existing fermions interact with the SO(3,1) gauge\nfield. In the absence of the other interactions the chiral condensate may\nappear and all fermionic excitations may acquire equal masses. Small\ncorrections to the gap equations due to the other interactions may cause the\nappearance of the observed hierarchy of masses.",
        "positive": "Axial anomaly and topological charge in lattice gauge theory with\n  Overlap Dirac operator: An explicit, detailed evaluation of the classical continuum limit of the\naxial anomaly/index density of the overlap Dirac operator is carried out in the\ninfinite volume setting, and in a certain finite volume setting where the\ncontinuum limit involves an infinite volume limit. Our approach is based on a\nnovel power series expansion of the overlap Dirac operator. The correct\ncontinuum expression is reproduced when the parameter $m_0$ is in the physical\nregion $0<m_0<2$. This is established for a broad range of continuum gauge\nfields. An analogous result for the fermionic topological charge, given by the\nindex of the overlap Dirac operator, is then established for a class of\ntopologically non-trivial fields in the aforementioned finite volume setting.\nProblematic issues concerning the index in the infinite volume setting are also\ndiscussed."
    },
    {
        "anchor": "First observation of the hidden-charm pentaquarks on lattice: The s-wave scattering of $\\Sigma_c \\bar{D}$ and $\\Sigma_c \\bar{D}^*$ in the\n$I(J^P) = \\frac{1}{2}(\\frac{1}{2}^-)$ channel is calculated in lattice QCD\nusing two ensembles with different volumes but the same lattice spacing $a\\sim\n0.08\\mathrm{fm}$ and pion mass $M_\\pi \\sim 294\\mathrm{MeV}$. The scattering\namplitudes near threshold are obtained by L\\\"uscher's finite volume method. We\nfind bound state poles in both $\\Sigma_c \\bar{D}$ and $\\Sigma_c \\bar{D}^*$\nchannels, which are possibly related to the $P_c(4312)$ and $P_c(4440) /\nP_c(4457)$ pentaquarks observed in experiments. The binding energy is\n$6(2)(2)$MeV for $\\Sigma_c \\bar{D}$ and $7(3)(1)$MeV for $\\Sigma_c \\bar{D}^*$,\nwhere the first error is the statistical error and the second is the systematic\nerror due to the lattice artifacts.",
        "positive": "Symmetries of the light hadron spectrum in high temperature QCD: Properties of QCD matter change significantly around the chiral crossover\ntemperature, and the effects on $U(1)_A$ and topological susceptibilities, as\nwell as the meson spectrum have been studied with much care. Baryons and the\neffect of parity doubling in this temperature range have been analyzed\npreviously by various other groups employing different setups. Here we\nconstruct suitable operators to investigate chiral and axial $U(1)_A$\nsymmetries in the baryon spectrum. Measurements for different volumes and\nquark-masses are done with two flavors of chirally symmetric domain-wall\nfermions at temperatures above the critical one. The possibility of emergent\n$SU(4)$ and $SU(2)_{CS}$ symmetries is discussed."
    },
    {
        "anchor": "Reply to \"Comment on `Lattice determination of Sigma - Lambda mixing' \": In this Reply, we respond to the above Comment. Our computation [Phys. Rev. D\n91 (2015) 074512] only took into account pure QCD effects, arising from quark\nmass differences, so it is not surprising that there are discrepancies in\nisospin splittings and in the Sigma - Lambda mixing angle. We expect that these\ndiscrepancies will be smaller in a full calculation incorporating QED effects.",
        "positive": "Lattice Perturbation Theory for $O(N)$-Symmetric $\u03c3$-Models with\n  General Nearest-Neighbour Action I. Conventional Perturbation Theory: We compute the beta-function and the anomalous dimension of all the\nnon-derivative operators of the theory up to three-loops for the most general\nnearest-neighbour O(N)-invariant action together with some contributions to the\nfour-loop beta-function. These results are used to compute the first analytic\ncorrections to various long-distance quantities as the correlation length and\nthe general spin-$n$ susceptibility. It is found that these corrections are\nextremely large for $RP^{N-1}$ models (especially for small values of N), so\nthat asymptotic scaling can be observed in these models only at very large\nvalues of beta. We also give the first three terms in the asymptotic expansion\nof the vector and tensor energies."
    },
    {
        "anchor": "B, Bs, K and pi weak matrix elements with physical light quarks: Calculations of pseudoscalar decay constants of B, Bs, K and pi mesons with\nphysical light quarks are presented. We use HISQ ensembles that include u,d,s\nand c sea quarks at three lattice spacings. HISQ is used for the valence light\nquarks and a radiatively improved NRQCD action for the heavy quarks. The key\nresults are f_{B^+}=0.184(4)$ GeV, f_{B_s}=0.224(4) GeV,\nf_{B_s}/f_{B^+}=1.217(8), f_{K^+}/f_{pi^+}=1.1916(21), f_{K^+}=155.37(34) MeV,\ngiving a significant improvement over previous results that required chiral\nextrapolation. We also calculate the Wilson flow scale w_0, finding\nw_0=0.1715(9) fm.",
        "positive": "Thermodynamics of Lattice QCD with Chiral 4-Fermion Interactions: We have studied lattice QCD with an additional, irrelevant 4-fermion\ninteraction having a U(1)xU(1) chiral symmetry, at finite temperatures. Adding\nthis 4-fermion term allowed us to work at zero quark mass, which would have\notherwise been impossible. The theory with 2 massless staggered quark flavours\nappears to have a first order finite temperature phase transition at N_t=4 for\nthe value of 4-fermion coupling we have chosen, in contrast to what is expected\nfor 2-flavour QCD. The pion screening mass is seen to vanish below this\ntransition, only to become massive and degenerate with the sigma (f_0) above\nthis transition where the chiral symmetry is restored, as is seen by the\nvanishing of the chiral condensate."
    },
    {
        "anchor": "Instanton Distribution in Quenched and Full QCD: In order to optimize cooling as a technique to study the instanton content of\nthe QCD vacuum, we have studied the effects of alternative algorithms, improved\nactions and boundary conditions on the evolution of single instantons and\ninstanton anti-instanton pairs. Using these results, we have extracted and\ncompared the instanton content of quenched and full QCD.",
        "positive": "Lattice measurement of the Isgur-Wise functions tau_1/2 and tau_3/2: We propose a method to compute the Isgur-Wise form factors tau_1/2(1) and\ntau_3/2(1) for the decay of B mesons into orbitally excited (P wave) D**\ncharmed mesons on the lattice in the static limit. We also present the result\nof an exploratory numerical simulation which shows that the signal/noise ratio\nallows for a more dedicated computation. We find tau_1/2(1)=0.38(5) and\ntau_3/2(1)= 0.53(8), with yet unknown systematic errors. These preliminary\nnumbers agree fairly well with theoretical expectation."
    },
    {
        "anchor": "Specific Heat Exponent for the 3-d Ising Model from a 24-th Order High\n  Temperature Series: We compute high temperature expansions of the 3-d Ising model using a\nrecursive transfer-matrix algorithm and extend the expansion of the free energy\nto 24th order. Using ID-Pade and ratio methods, we extract the critical\nexponent of the specific heat to be alpha=0.104(4).",
        "positive": "Multi-Particle Baryon Spectroscopy: In Nature the excited states of the hadron spectrum appear as resonances.\nConsequently, there has been significant interest in studying the excited\nbaryon spectrum using lattice QCD. With this in mind we perform spectroscopic\ncalculations with five-quark interpolating fields. Stochastic estimation\ntechniques are used in order to calculate the loop propagators, with dilution\nin spin, colour and time implemented as a means of variance reduction. We\npresent effective mass plots extracted from these five-quark interpolators, and\nexamine the contributions from fully-connected and loop-containing pieces of\nthe correlation function, keeping in mind their use in future corre- lation\nmatrix studies."
    },
    {
        "anchor": "Pion-Nucleon Sigma Term in Lattice QCD: We calculate both connected and disconnected contribution to the $\\pi$-$N$\n$\\sigma$-term in quenched lattice QCD with Wilson quark action on a $12^3\\times\n20$ lattice at $\\beta=5.7$. The latter is evaluated with the aid of the variant\nwall source method, which was previously applied successfully for extraction of\n$\\pi$-$\\pi$ scattering lengths and $\\eta^\\prime$ meson mass. We found that the\ndisconnected contribution is about twice larger than the connected one. The\nvalue for the full $\\pi$-$N$ $\\sigma$ term $\\sigma=40-60$ MeV is consistent\nwith the experimental estimates. The nucleon matrix element of the strange\nquark density $\\bar s s$ is fairly large in our result.",
        "positive": "Conserved charge fluctuations at vanishing and non-vanishing chemical\n  potential: Up to 6th order cumulants of fluctuations of net baryon-number, net electric\ncharge and net strangeness as well as correlations among these conserved charge\nfluctuations are now being calculated in lattice QCD. These cumulants provide a\nwealth of information on the properties of strong-interaction matter in the\ntransition region from the low temperature hadronic phase to the quark-gluon\nplasma phase. They can be used to quantify deviations from hadron resonance gas\n(HRG) model calculations which frequently are used to determine thermal\nconditions realized in heavy ion collision experiments. Already some second\norder cumulants like the correlations between net baryon-number and net\nstrangeness or net electric charge differ significantly at temperatures above\n155 MeV in QCD and HRG model calculations. We show that these differences\nincrease at non-zero baryon chemical potential constraining the applicability\nrange of HRG model calculations to even smaller values of the temperature."
    },
    {
        "anchor": "Equation of state near the first order phase transition point of SU(3)\n  gauge theory using gradient flow: We study energy gap (latent heat) between the hot and cold phases at the\nfirst order phase transition point of the SU(3) gauge theory. Performing\nsimulations on lattices with various spatial volumes and lattice spacings, we\ncalculate the energy gap by a method using the Yang-Mills gradient flow and\ncompare it with that by the conventional derivative method.",
        "positive": "The MSSM Electroweak Phase Transition on the Lattice: We study the MSSM finite temperature electroweak phase transition with\nlattice Monte Carlo simulations, for a large Higgs mass (m_H ~ 95 GeV) and\nlight stop masses (m_tR ~ 150...160 GeV). We employ a 3d effective field theory\napproach, where the degrees of freedom appearing in the action are the SU(2)\nand SU(3) gauge fields, the weakly interacting Higgs doublet, and the strongly\ninteracting stop triplet. We determine the phase diagram, the critical\ntemperatures, the scalar field expectation values, the latent heat, the\ninterface tension and the correlation lengths at the phase transition points.\nExtrapolating the results to the infinite volume and continuum limits, we find\nthat the transition is stronger than indicated by 2-loop perturbation theory,\nguaranteeing that the MSSM phase transition is strong enough for baryogenesis\nin this regime. We also study the possibility of a two-stage phase transition,\nin which the stop field gets an expectation value in an intermediate phase. We\nfind that a two-stage transition exists non-perturbatively, as well, but for\nsomewhat smaller stop masses than in perturbation theory. Finally, the latter\nstage of the two-stage transition is found to be extremely strong, and thus it\nmight not be allowed in the cosmological environment."
    },
    {
        "anchor": "$K$ and $D$ oscillations in the Standard Model and its extensions from\n  $N_f=2+1+1$ Twisted Mass LQCD: We present the first $N_f=2+1+1$ results for the matrix elements of the\noperators describing neutral $K$ and $D$ mixing in the Standard Model and its\nextensions. The combination of maximally twisted sea quarks and\nOsterwalder-Seiler valence quarks ensures $\\mathcal{O}(a)$-improvement and\ncontinuum like renormalization pattern. We have used the $N_f=2+1+1$ dynamical\nquark gauge configurations generated by ETMC. Simulations include three lattice\nspacings in the interval $[0.06:0.09]$ fm and pseudoscalar meson masses in the\nrange $[230:500]$ MeV. Our results are extrapolated to the continuum limit and\nto the physical quark masses. The calculation of the renormalization constants\nhas been performed non-perturbatively in the RI-MOM scheme.",
        "positive": "Finite volume effects for meson masses and decay constants: We present a detailed numerical study of finite volume effects for masses and\ndecay constants of the octet of pseudoscalar mesons. For this analysis we use\nchiral perturbation theory and asymptotic formulae a la Luscher and propose an\nextension of the latter beyond the leading exponential term. We argue that such\na formula, which is exact at the one-loop level, gives the numerically dominant\npart at two loops and beyond. Finally, we discuss the possibility to determine\nlow energy constants from the finite volume dependence of masses and decay\nconstants."
    },
    {
        "anchor": "Monopole Condensation in Lattice SU(2) QCD: This is the short review of Monte-Carlo studies of quark confinement in\nlattice QCD. After abelian projections both in the maximally abelian and\nPolyakov gauges, it is seen that the monopole part alone is responsible for\nconfinement. A block spin transformation on the dual lattice suggests that\nlattice $SU(2)$ QCD is always ( for all $\\beta$) in the monopole condensed\nphase and so in the confinement phase in the infinite volume limit.",
        "positive": "Non-perturbative renormalization of bilinear operators with M\u00f6bius\n  domain-wall fermions in the coordinate space: We study the non-perturbative determination of the renormalization constants\nof flavor non-singlet quark bilinear operators on the lattice. The\nrenormalization condition is imposed on correlation functions of bilinear\noperators in the coordinate space. The results are converted to the value at 2\nGeV in the $\\rm\\overline{MS}$ scheme by a perturbative matching. The\ncalculation is carried out on gauge configurations generated with the Mobius\ndomain-wall fermions at two lattice spacings $a^{-1} = 2.4$ GeV and $a^{-1} =\n3.6$ GeV."
    },
    {
        "anchor": "Strong Coupling Lattice Schwinger Model on Large Spherelike Lattices: The lattice regularized Schwinger model for one fermion flavor and in the\nstrong coupling limit is studied through its equivalent representation as a\nrestricted 8-vertex model. The Monte Carlo simulation on lattices with\ntorus-topology is handicapped by a severe non-ergodicity of the updating\nalgorithm; introducing lattices with spherelike topology avoids this problem.\nWe present a large scale study leading to the identification of a critical\npoint with critical exponent $\\nu=1$, in the universality class of the Ising\nmodel or, equivalently, the lattice model of free fermions.",
        "positive": "Supermultiplets of the N=1 supersymmetric Yang-Mills theory in the\n  continuum limit: The spectrum of N=1 supersymmetric Yang-Mills theory, calculated on the\nlattice, is presented. The masses have been determined on three different\nlattice spacings and extrapolated towards vanishing gluino mass. We present the\nextrapolation to the continuum limit which is consistent with the formation of\ndegenerate supermultiplets."
    },
    {
        "anchor": "High Precision Fundamental Constants using Lattice Perturbation Theory: The HPQCD collaboration has a program for determining the fundamental\nconstants of the Standard Model Lagrangian from lattice QCD. The most accurate\nmethod of doing this uses the n_f=2+1 improved staggered MILC ensembles with\nchiral fitting and multi-loop perturbative renormalisation to connect to the\ncontinuum \\msbar scheme. This program has already been very successful with the\nrecent strong coupling constant determination at three-loops from 28\nobservables at three lattice spacings, and the one-loop light quark mass\ncalculation last year. Here a preliminary result is presented for the\nfirst-ever lattice determination of the two-loop multiplicative quark mass\nrenormalisation. The perturbative calculation involved was automated in the\ngeneration of the Feynman rules, and the generation and coding of all of the\nroughly 30 Feynman diagrams. The full formal framework for lattice quark mass\nrenormalisation is given, including the cancellation of infrared divergences in\nintermediate diagrams. The result was checked by evaluation in three separate\ngauges and by two authors independently, showing the incredible flexibility and\npower of this perturbative methodology. Our preliminary result for the two-loop\nperturbative matching factor, and of systematic errors associated with\nhigher-orders, gives \\msbar masses at a 2 GeV scale of $m_s = 87(0)(4)(4)(0)$\nMeV, and $\\frac12(m_u+m_d) = 3.3(0)(2)(2)(0)$ MeV, where the respective\nuncertainties are from lattice statistical, lattice systematic, perturbative,\nand electromagnetic and isospin effects. The perturbative errors are a factor\nof two smaller than in our previous study, and we anticipate reducing this\nsomewhat further from additional analysis of the systematics.",
        "positive": "The Sine Gordon Model: Perturbation Theory and Cluster Monte Carlo: We study the expansion of the surface thickness in the 2-dimensional lattice\nSine Gordon model in powers of the fugacity z. Using the expansion to order\nz**2, we derive lines of constant physics in the rough phase. We describe and\ntest a VMR cluster algorithm for the Monte Carlo simulation of the model. The\nalgorithm shows nearly no critical slowing down. We apply the algorithm in a\ncomparison of our perturbative results with Monte Carlo data."
    },
    {
        "anchor": "Fermion RG blocking transformations and IR structure: We explore fermion RG block-spinning transformations on the lattice with the\naim of studying the IR structure of gauge theories and, in particular, the\nexistence of IR fixed points for varying fermion content. In the case of light\nfermions the main concern and difficulty is ensuring locality of any adopted\nblocking scheme. We discuss the problem of constructing a local blocked fermion\naction in the background of arbitrary gauge fields. We then discuss the\ncarrying out of accompanying gauge field blocking. In the presence of the\nblocked fermions implementation of MCRG is not straightforward. By adopting\njudicious approximations we arrive at an easily implementable approximate RG\nrecursion scheme that allows quick, inexpensive estimates of the location of\nconformal windows for various groups and fermion representations. We apply this\nscheme to locate the conformal windows in the case of SU(2) and SU(3) gauge\ngroups. Some of the reasons for the apparent efficacy of this and similar\ndecimation schemes are discussed.",
        "positive": "A performance evaluation of CCS QCD Benchmark on the COMA (Intel(R) Xeon\n  Phi$^{TM}$, KNC) system: The most computationally demanding part of Lattice QCD simulations is solving\nquark propagators. Quark propagators are typically obtained with a linear\nequation solver utilizing HPC machines. The CCS QCD Benchmark is a benchmark\nprogram solving the Wilson-Clover quark propagator, and is developed at the\nCenter for Computational Sciences (CCS), University of Tsukuba. We optimized\nthe benchmark program for a \\Intel \\XeonPhi (Knights Corner, KNC) system named\n\"COMA (PACS-IX)\" at CCS Tsukuba under the Intel Parallel Computing Center\nprogram. A single precision BiCGStab solver with the overlapped Restricted\nAdditive Schwarz (RAS) preconditioner was implemented using SIMD intrinsics,\nOpenMP and MPI in the offload mode. With the reverse-offloading technique, we\ncould reduce the communication and offloading overheads. We observed a\nperformance of $\\sim 200$ GFlops sustained for the Wilson-Clover hopping matrix\nmultiplication on the lattice sizes larger than $24^3\\times 32$ on a sinlge\ncard of the COMA system. A good weak scaling perofmace was observed on the\nlocal lattice sizes larger than $24^3\\times 32$."
    },
    {
        "anchor": "Present Constraints on the H-dibaryon at the Physical Point from Lattice\n  QCD: The current constraints from lattice QCD on the existence of the H-dibaryon\nare discussed. With only two significant lattice QCD calculations of the\nH-dibaryon binding energy at approximately the same lattice spacing, the forms\nof the chiral and continuum extrapolations to the physical point are not\ndetermined. In this brief report, we consider the constraints on the H-dibaryon\nimposed by two simple chiral extrapolations. In both instances, the\nextrapolation to the physical pion mass allows for a bound H-dibaryon or a\nnear-threshold scattering state. Further lattice QCD calculations are required\nto clarify this situation.",
        "positive": "Duality and scaling in 3-dimensional scalar electrodynamics: Three-dimensional scalar electrodynamics, with a local U(1) gauge symmetry,\nis believed to be dual to a scalar theory with a global U(1) symmetry, near the\nphase transition point. The conjectured duality leads to definite predictions\nfor the scaling exponents of the gauge theory transition in the type II region,\nand allows thus to be scrutinized empirically. We review these predictions, and\ncarry out numerical lattice Monte Carlo measurements to test them: a number of\nexponents, characterising the two phases as well as the transition point, are\nfound to agree with expectations, supporting the conjecture. We explain why\nsome others, like the exponent characterising the photon correlation length,\nappear to disagree with expectations, unless very large system sizes and the\nextreme vicinity of the transition point are considered. Finally, we remark\nthat in the type I region the duality implies an interesting quantitative\nrelationship between a magnetic flux tube and a 2-dimensional non-topological\nsoliton."
    },
    {
        "anchor": "The Physical Phase of Dimensionally Reduced Gauge Theories: We investigate the relationship between the high temperature deconfined phase\nof the SU(2) gauge theory to the phases of the corresponding three dimensional\nadjoint Higgs model. For various temperatures we simulate the effective theory\nin a neighbourhood of the physical states, that is of those values of the\ncoupling constants that describe the infrared behaviour of the four dimensional\ntheory and which have been calculated by applying dimensional reduction\ntechniques. We show that the physical points belong to the confined phase of\nthe SU(2) adjoint Higgs model.",
        "positive": "Upper Higgs boson mass bounds from a chirally invariant lattice\n  Higgs-Yukawa model: We establish the cutoff-dependent upper Higgs boson mass bound by means of\ndirect lattice computations in the framework of a chirally invariant lattice\nHiggs-Yukawa model emulating the same chiral Yukawa coupling structure as in\nthe Higgs-fermion sector of the Standard Model. As expected from the triviality\npicture of the Higgs sector, we observe the upper mass bound to decrease with\nrising cutoff parameter $\\Lambda$. Moreover, the strength of the fermionic\ncontribution to the upper mass bound is explored by comparing to the\ncorresponding analysis in the pure $\\Phi^4$-theory."
    },
    {
        "anchor": "Dilute Liquid of Instanton and Its Topological Charge Dominate the QCD\n  Vacuum: APE smearing and overlap-Dirac operator are combined to filter QCD vacuum\nconfigurations. The results obtained from overlap fermions and improved 5Li\ncooling are compared, both of them exhibit structures of dilute liquid of\ninstanton. Finally the overlap fermions, improved 5Li cooling and APE smearing\nare combined to calculate the topological charge and identify the structure of\nQCD vacuum. The results suggest dilute liquid of instanton dominance of\ntopological charge fluctuations in quenched lattice QCD.",
        "positive": "Monte Carlo Calculation of Phase Shift in Four Dimensional O(4) $\u03c6^4$\n  Theory: The phase shift of the O(4) symmetric $\\phi^4$ theory in the symmetric phase\nis calculated numerically using the relation between phase shift and energy\nlevels of two-particle states recently derived by L\\\"{u}scher. The results\nagree with the prediction of perturbation theory. A practical difficulty of the\nmethod for a reliable extraction of the phase shift for large momenta due to\nthe necessity of a precise determination of excited two-particle energy levels\nis pointed out."
    },
    {
        "anchor": "Improved analysis of isovector nucleon matrix elements with $N_f=2+1$\n  flavors of $\\mathcal{O}(a)$ improved Wilson fermions: We present an update of our determination of the isovector charges\n$g_A^{u-d}$, $g_S^{u-d}$ and $g_T^{u-d}$, and the isovector twist-2 forward\nmatrix elements $\\langle x\\rangle_{u-d}$, $\\langle x\\rangle_{\\Delta u-\\Delta\nd}$ and $\\langle x\\rangle_{\\delta u-\\delta d}$ on the $N_\\mathrm{f}=2+1$ gauge\nensembles generated by the Coordinated Lattice Simulations (CLS) effort. We\nhave significantly extended our coverage of the parameter space by adding\nensembles at the physical pion mass and fine lattice spacing, at\nnearly-physical pion masses and very fine lattice spacings, and at very large\nphysical lattice volumes, enabling a well-controlled extrapolation to the\nphysical point. Another major improvement is achieved owing to the extended\nrange of source-sink separations, which allows us to perform two-state fits to\nsummed correlator ratios, leading to a much higher level of control over\nexcited-state effects. Systematic uncertainties from the chiral, continuum and\ninfinite-volume extrapolations are incorporated via model averages based on the\nAkaike Information Criterion. Our final results at the physical point are\n$g_A^{u-d} = 1.254(19)_\\mathrm{stat}(15)_\\mathrm{sys}[24]_\\mathrm{total}$,\n$g_S^{u-d} = 1.203(77)_\\mathrm{stat}(81)_\\mathrm{sys}[112]_\\mathrm{total}$,\n$g_T^{u-d} = 0.993(15)_\\mathrm{stat}(05)_\\mathrm{sys}[16]_\\mathrm{total}$,\n$\\langle x\\rangle_{u-d} =\n0.153(15)_\\mathrm{stat}(10)_\\mathrm{sys}[17]_\\mathrm{total}$, $\\langle\nx\\rangle_{\\Delta u - \\Delta d} =\n0.207(15)_\\mathrm{stat}(06)_\\mathrm{sys}[16]_\\mathrm{total}$, and $\\langle\nx\\rangle_{\\delta u - \\delta d} =\n0.195(17)_\\mathrm{stat}(15)_\\mathrm{sys}[23]_\\mathrm{total}$. While our results\nfor the isovector charges are in excellent agreement with the FLAG\\,21\naverages, we note that our error for the tensor charge $g_T^{u-d}$ is\nconsiderably smaller.",
        "positive": "$B\\to D^\\ast\\ell\u03bd$ at non-zero recoil: The current status of the lattice-QCD calculations of the form factors of the\n$B\\to D^\\ast\\ell\\nu$ semileptonic decay is reviewed. Particular emphasis is\ngiven to the most mature calculation at non-zero recoil coming from the\nFermilab Lattice and MILC collaborations. Blinded, preliminary results for the\nform factors are shown, including a preliminary, but detailed error budget. The\nlattice results seem to favor a large slope at small recoil, in contrast to the\nlatest untagged results coming from the Belle collaboration. A comprehensive\ncomparison between the latest BGL $z$ expansions of Belle, Babar, the lattice\nand a joint BGL fit including lattice and Belle data is presented, and a\nroadmap to improve the current calculation is discussed. The current\nimplications for $V_{cb}$ and $R(D^\\ast)$ are discussed."
    },
    {
        "anchor": "Numerical Study of the Gluon Propagator in Lattice Landau Gauge: the\n  Three-Dimensional Case: We study the infrared behavior of the gluon propagator in lattice Landau\ngauge, for pure SU(2) lattice gauge theory in a three-dimensional lattice.\nSimulations are done for nine different values of the coupling $\\beta$, from\n$\\beta = 0$ (strong coupling) to $\\beta = 6.0$ (in the weak-coupling region).\nIn the limit of large lattice volumes, we observe in all cases a gluon\npropagator decreasing as the momentum goes to zero.",
        "positive": "Application of the operator product expansion to the short distance\n  behavior of nuclear potentials: We investigate the short distance behavior of nucleon-nucleon (NN) potentials\ndefined through Bethe-Salpeter wave functions, by perturbatively calculating\nanomalous dimensions of 6-quark operators in QCD. Thanks to the asymptotic\nfreedom of QCD, 1-loop computations give certain exact results for the\npotentials in the zero distance limit. In particular the functional form of the\nS-state central NN potential at short distance $r$ is predicted to be a little\nweaker than $r^{-2}$. On the other hand, due to the intriguing character of the\nanomalous dimension spectrum, perturbative considerations alone can not\ndetermine whether this potential is repulsive or attractive at short distances.\nA crude estimation suggests that the force at short distance is repulsive, as\nfound numerically in lattice QCD. A similar behavior is found for the tensor\npotential."
    },
    {
        "anchor": "Sigma term and strangeness content of the nucleon: A status report is given for a joint project of the\nBudapest-Marseille-Wuppertal collaboration and the Regensburg group to study\nthe quark mass-dependence of octet baryons in SU(3) Baryon XPT. This\nformulation is expected to extend to larger masses than Heavy-Baryon XPT. Its\napplicability is tested with 2+1 flavor data which cover three lattice spacings\nand pion masses down to about 190 MeV, in large volumes. Also polynomial and\nrational interpolations in M_\\pi^2 and M_K^2 are used to assess the uncertainty\ndue to the ansatz. Both frameworks are combined to explore the precision to be\nexpected in a controlled determination of the nucleon sigma term and\nstrangeness content.",
        "positive": "Second Order Phase Transition in Anisotropic Lattice Gauge Theories with\n  Extra Dimensions: Field theories with extra dimensions live in a limbo. While their classical\nsolutions have been the subject of considerable study, their quantum aspects\nare difficult to control. A special class of such theories are anisotropic\ngauge theories. The anisotropy was originally introduced to localize chiral\nfermions. Their continuum limit is of practical interest and it will be shown\nthat the anisotropy of the gauge couplings plays a crucial role in opening the\nphase diagram of the theory to a new phase, that is separated from the others\nby a second order phase transition. The mechanism behind this is generic for a\ncertain class of models, that can be studied with lattice techniques. This\nleads to new perspectives for the study of quantum effects of extra dimensions."
    },
    {
        "anchor": "Lattice QCD calculation of $\u03c0\u03c0$ scattering length: We study s-wave pion-pion ($\\pi\\pi$) scattering length in lattice QCD for\npion masses ranging from 330 MeV to 466 MeV. In the \"Asqtad\" improved staggered\nfermion formulation, we calculate the $\\pi\\pi$ four-point functions for isospin\nI=0 and 2 channels, and use chiral perturbation theory at next-to-leading order\nto extrapolate our simulation results. Extrapolating to the physical pion mass\ngives the scattering lengths as $m_\\pi a_0^{I=2} = -0.0416(2)$ and $m_\\pi\na_0^{I=0} = 0.186(2)$ for isospin I=2 and 0 channels, respectively. Our lattice\nsimulation for $\\pi\\pi$ scattering length in the I=0 channel is an exploratory\nstudy, where we include the disconnected contribution, and our preliminary\nresult is near to its experimental value. These simulations are performed with\nMILC 2+1 flavor gauge configurations at lattice spacing $a \\approx 0.15$ fm.",
        "positive": "Strong-coupling study of the Gribov ambiguity in lattice Landau gauge: We study the strong-coupling limit beta=0 of lattice SU(2) Landau gauge\nYang-Mills theory. In this limit the lattice spacing is infinite, and thus all\nmomenta in physical units are infinitesimally small. Hence, the infrared\nbehavior can be assessed at sufficiently large lattice momenta. Our results\nshow that at the lattice volumes used here, the Gribov ambiguity has an\nenormous effect on the ghost propagator in all dimensions. This underlines the\nseverity of the Gribov problem and calls for refined studies also at finite\nbeta. In turn, the gluon propagator only mildly depends on the Gribov\nambiguity."
    },
    {
        "anchor": "Quenched twisted mass QCD at small quark masses and in large volume: As a test of quenched lattice twisted mass QCD, we compute the\nnon-perturbatively O($a$) improved pseudoscalar and vector meson masses and the\npseudoscalar decay constant down to $M_{\\rm PS}/M_{\\rm V} = 0.467(13)$ at\n$\\beta=6$ in large volume. We check the absence of exceptional configurations\nand -- by further data at $\\beta=6.2$ -- the size of scaling violations. The\nCPU time cost for reaching a given accuracy is close to that with ordinary\nWilson quarks at $M_{\\rm PS}/M_{\\rm V} \\simeq 0.6$ and grows smoothly as\n$M_{\\rm PS}/M_{\\rm V}$ decreases.",
        "positive": "SU(N) gauge theories for all N: We show that SU(N) gauge theories in 2+1 dimensions are close to N=\\infty for\nN \\geq 2. The dimensionful coupling, g^2, is proportional to 1/N, at large N,\nconfirming the usual diagram-based expectation. Preliminary calculations in 3+1\ndimensions indicate that the same is true there."
    },
    {
        "anchor": "Dual formulations of Polyakov loop lattice models: Dual representations are constructed for non-abelian lattice spin models with\nU(N) and SU(N) symmetry groups, for all N and in any dimension. These models\nare usually related to the effective models describing the interaction between\nPolyakov loops in the strong coupled QCD. The original spin degrees of freedom\nare explicitly integrated out and a dual theory appears to be a local theory\nfor the dual integer-valued variables. The construction is performed for the\npartition function and for the most general correlation function. The latter\ninclude the two-point function corresponding to quark-anti-quark free energy\nand the N-point function related to the free energy of a baryon. We consider\nboth pure gauge models and models with static fermion determinant for both the\nstaggered and Wilson fermions with an arbitrary number of flavours. While the\nBoltzmann weights of such models are complex in the presence of non-zero\nchemical potential the dual Boltzmann weights appear to be strictly positive on\nadmissible configurations. An essential part of this work with respect to\nprevious studies is an extension of the dual representation to the case of 1)\nan arbitrary value of the temporal coupling constant in the Wilson action and\n2) an arbitrary number of flavours of static quark determinants. The\napplications and extensions of the results are discussed in detail. In\nparticular, we outline a possible approach to Monte-Carlo simulations of the\ndual theory, to the large N expansion and to the development of a tensor\nrenormalization group.",
        "positive": "Nucleon strange quark content from two-flavor lattice QCD with exact\n  chiral symmetry: Strange quark content of the nucleon is calculated in dynamical lattice QCD\nemploying the overlap fermion formulation. For this quantity, exact chiral\nsymmetry guaranteed by the Ginsparg-Wilson relation is crucial to avoid large\ncontamination due to a possible operator mixing with $\\bar{u}u+\\bar{d}d$. Gauge\nconfigurations are generated with two dynamical flavors on a 16^3 x 32 lattice\nat a lattice spacing a \\simeq 0.12fm. We directly calculate the relevant\nthree-point function on the lattice including a disconnected strange quark loop\nutilizing the techniques of all-to-all quark propagator and low-mode averaging.\nOur result f_{T_s} = 0.032(8)(22), is in good agreement with our previous\nindirect estimate using the Feynman-Hellmann theorem."
    },
    {
        "anchor": "Results and Perspectives in HEP, vis-a-vis Lattice QCD: I review in this presentation some aspects of phenomenology in High Energy\nPhysics which are related to recent and possibly future progress in lattice\nQCD. In particular, I cover (i) the extraction of CKM matrix elements from B\nphysics, (ii) the determination of epsilon'/epsilon, as well as (iii) some\nissues emerged in the physics of high energy jets produced in hadronic\ncollisions, where input from non-perturbative calculations would benefit our\ncapability to perform better theoretical predictions.",
        "positive": "The Eta-prime and Cooling with Staggered Fermions: We present a calculation of the mass of the eta-prime meson using quenched\nand dynamical staggered fermions. We also discuss the effects of \"cooling\" and\nsuggest its use as a quantitative tool."
    },
    {
        "anchor": "Lattice study of the Higgs-Yukawa model in and beyond the Standard Model: We derive finite-size scaling formulae for four-dimensional Higgs-Yukawa\nmodels near the Gaussian fixed point. These formulae will play an essential\nrole in future, detailed investigation of such models. In particular, they can\nbe used to determine the nature of the observed phase transitions, and confirm\nor rule out the possibility of having non-trivial fixed points in the\nHiggs-Yukawa models. Our scaling formula for Binder's cumulant is tested\nagainst lattice simulations carried out at weak couplings, and good agreement\nis found. As a separate project, we also present preliminary results from our\nstudy of a chirally-invariant Higgs-Yukawa model including a dimension-six\noperator at finite temperature. Our work provides first indications of\nfirst-order temperature-induced phase transitions near the infinite cutoff\nlimit in this model.",
        "positive": "Non-perturbative renormalization in lattice QCD: Recent developments in non-perturbative renormalization for lattice QCD are\nreviewed with a particular emphasis on RI/MOM scheme and its variants, RI/SMOM\nschemes. Summary of recent developments in Schroedinger functional scheme, as\nwell as the summary of related topics are presented. Comparison of strong\ncoupling constant and the strange quark mass from various methods are made."
    },
    {
        "anchor": "Connecting Matrix Elements to Multi-Hadron Form-Factors: We discuss developments in calculating multi-hadron form-factors and\ntransition processes via lattice QCD. Our primary tools are finite-volume\nscaling relations, which map spectra and matrix elements to the corresponding\nmulti-hadron infinite-volume amplitudes. We focus on two hadron processes\nprobed by an external current, and provide various checks on the finite-volume\nformalism in the limiting cases of perturbative interactions and systems\nforming a bound state. By studying model-independent properties of the\ninfinite-volume amplitudes, we are able to rigorously define form-factors of\nresonances.",
        "positive": "Tests of hadronic vacuum polarization fits for the muon anomalous\n  magnetic moment: We construct a physically motivated model for the isospin-one non-strange\nvacuum polarization function Pi(Q^2) based on a spectral function given by\nvector-channel OPAL data from hadronic tau decays for energies below the tau\nmass and a successful parametrization, employing perturbation theory and a\nmodel for quark-hadron duality violations, for higher energies. Using a\ncovariance matrix and Q^2 values from a recent lattice simulation, we then\ngenerate fake data for Pi(Q^2) and use it to test fitting methods currently\nemployed on the lattice for extracting the hadronic vacuum polarization\ncontribution to the muon anomalous magnetic moment. This comparison reveals a\nsystematic error much larger than the few-percent total error sometimes claimed\nfor such extractions in the literature. In particular, we find that errors\ndeduced from fits using a Vector Meson Dominance ansatz are misleading,\ntypically turning out to be much smaller than the actual discrepancy between\nthe fit and exact model results. The use of a sequence of Pad\\'{e}\napproximants, recently advocated in the literature, appears to provide a safer\nfitting strategy."
    },
    {
        "anchor": "$2D$ and $3D$ Antiferromagnetic Ising Model with topological term at\n  $\u03b8=\u03c0$: We study the two and three-dimensional Antiferromagnetic Ising Model with an\nimaginary magnetic field $i\\theta$ at $\\theta = \\pi$. We use a new geometric\nalgorithm which does not present a sign problem. This allows us to perform\nefficient numerical simulations of this system.",
        "positive": "Induced Chern-Simons term in lattice QCD at finite temperature: The general conditions for the Chern-Simons action to be induced as a\nnonuniversal contribution of fermionic determinant are formulated in the finite\ntemperature lattice QCD. The dependence of the corresponding action coefficient\non nonuniversal parameters (chemical potentials, vacuum features, etc. ) is\nexplored. Special attention is paid to the role of $A_0$-condensate if it is\navailable in this theory."
    },
    {
        "anchor": "Landau gauge gluon vertices from Lattice QCD: In lattice QCD the computation of one-particle irreducible (1PI) Green's\nfunctions with a large number (> 2) of legs is a challenging task. Besides\ntuning the lattice spacing and volume to reduce finite size effects, the\nproblems associated with the estimation of higher order moments via Monte Carlo\nmethods and the extraction of 1PI from complete Green's functions are\nlimitations of the method. Herein, we address these problems revisiting the\ncalculation of the three gluon 1PI Green's function.",
        "positive": "Decay Constants of Heavy-Light Mesons: The decay constants of the heavy-light pseudoscalar mesons are studied in a\nhigh statistics run using the Wilson action at $\\beta=6.0$ and $\\beta=6.2$, and\nthe clover action at $\\beta=6.0$. The systematics of $O(a)$ discretisation\nerrors are discussed. Our best estimates of the decay constants are: $f_D$ =\n218(9) MeV, $f_D/f_{Ds}$ = 1.11(1) and we obtain preliminary values for $f_B$."
    },
    {
        "anchor": "A Lattice Study of the Magnetic Moment and the Spin Structure of the\n  Nucleon: Using an approach free from momentum extrapolation, we calculate the nucleon\nmagnetic moment and the fraction of the nucleon spin carried by the quark\nangular momentum in the quenched lattice QCD approximation. Quarks with three\nvalues of lattice masses, 210, 124 and 80 MeV, are formulated on the lattice\nusing the standard Wilson approach. At every mass, 100 gluon configurations on\n16^3 x 32 lattice with \\beta=6.0 are used for statistical averaging. The\nresults are compared with the previous calculations with momentum\nextrapolation. The contribution of the disconnected diagrams is studied at the\nlargest quark mass using noise theory technique.",
        "positive": "Non-compact Lattice QED with Two Charges: Phase Diagram and\n  Renormalization Group Flow: The phase diagram of non-compact lattice QED in four dimensions with\nstaggered fermions of charges 1 and $-1/2$ is investigated. The renormalized\ncharges are determined and found to be in agreement with perturbation theory.\nThis is an indication that there is no continuum limit with non-vanishing\nrenormalized gauge coupling, and that the theory has a validity bound for every\nfinite value of the renormalized coupling. The renormalization group flow of\nthe charges is investigated and an estimate for the validity bound as a\nfunction of the cut-off is obtained. Generalizing this estimate to all fermions\nin the Standard Model,it is found that a cut-off at the Planck scale implies\nthat $\\alpha_R$ has to be less than $1/80$. Due to spontaneous chiral symmetry\nbreaking, strongly bound fermion-antifermion composite states are generated.\nTheir spectrum is discussed."
    },
    {
        "anchor": "First-principles calculation of electroweak box diagrams from lattice\n  QCD: We present the first realistic lattice QCD calculation of the $\\gamma W$-box\ndiagrams relevant for beta decays. The nonperturbative low-momentum integral of\nthe $\\gamma W$ loop is calculated using a lattice QCD simulation, complemented\nby the perturbative QCD result at high momenta. Using the pion semileptonic\ndecay as an example, we demonstrate the feasibility of the method. By using\ndomain wall fermions at the physical pion mass with multiple lattice spacings\nand volumes, we obtain the axial $\\gamma W$-box correction to the semileptonic\npion decay, $\\Box_{\\gamma\nW}^{VA}\\big|_{\\pi}=2.830(11)_{\\mathrm{stat}}(26)_{\\mathrm{sys}}\\times10^{-3}$,\nwith the total uncertainty controlled at the level of $\\sim1$\\%. This study\nsheds light on the first-principles computation of the $\\gamma W$-box\ncorrection to the neutron decay, which plays a decisive role in the\ndetermination of $|V_{ud}|$.",
        "positive": "$\u039b_b \\to p l^- \\bar\u03bd$ form factors from lattice QCD with\n  static b quarks: We present a lattice QCD calculation of form factors for the decay $\\Lambda_b\n\\to p \\mu^- \\bar{\\nu}$, which is a promising channel for determining the CKM\nmatrix element $|V_{ub}|$ at the Large Hadron Collider. In this initial study\nwe work in the limit of static b quarks, where the number of independent form\nfactors reduces to two. We use dynamical domain-wall fermions for the light\nquarks, and perform the calculation at two different lattice spacings and at\nmultiple values of the light-quark masses in a single large volume. Using our\nform factor results, we calculate the $\\Lambda_b \\to p \\mu^- \\bar{\\nu}$\ndifferential decay rate in the range $14 GeV^2 \\leq q^2 \\leq q^2_{max}$, and\nobtain the integral $\\int_{14 GeV^2}^{q^2_{max}} [d\\Gamma/dq^2] dq^2 /\n|V_{ub}|^2 = 15.3 \\pm 4.2 ps^{-1}$. Combined with future experimental data,\nthis will give a novel determination of $|V_{ub}|$ with about 15\\% theoretical\nuncertainty. The uncertainty is dominated by the use of the static\napproximation for the b quark, and can be reduced further by performing the\nlattice calculation with a more sophisticated heavy-quark action."
    },
    {
        "anchor": "Lattice Calculations of Heavy Quark Potential at Finite Temperature: We report on the lattice calculations of the heavy quark potential at $T>0$\nin 2+1 flavor QCD at physical quark masses using the Highly Improved Staggered\nQuark discretization. We study in detail the systematic effects in the\ndetermination of the real and imaginary parts of the potential when using the\nmoment method.",
        "positive": "Approximate Ginsparg-Wilson Fermions for QCD: Lattice fermions obeying the Ginsparg-Wilson relation do correctly represent\nthe physical properties related to chirality. This can be achieved by local\nfermions, which involve an infinite number of couplings, however. For practical\npurposes, it is useful to first construct approximate Ginsparg-Wilson fermions\nwithin a short range. We report on a successful construction in QCD at \\beta\n=6. The good quality of the approximation is observed from the spectrum, which\nis situated close to a Ginsparg-Wilson circle. These fermions also provide an\nexcellent approximation to rotational symmetry and they are promising for a\ngood scaling, since they arise from the perfect action framework. Their\ninsertion into the overlap formula renders the Ginsparg-Wilson relation exact.\nIt leads to an improved overlap fermion with a high level of locality. This\ninsertion is statistically on safe grounds at about \\beta > 5.6."
    },
    {
        "anchor": "Spin dependent potentials from SU(2) gauge theory: We present results on spin dependent potentials from lattice simulations of\nSU(2) gauge theory. The Coulomb like short range part of the central potential\nis identified as a mixed vector-scalar exchange while the linear long range\npart is pure scalar.",
        "positive": "Comparing Different Improvement Programs for the N-Vector Model: We discuss the connection between various types of improved actions in the\ncontext of the two-dimensional sigma-model. We also discuss spectrum-improved\nactions showing that these actions do not have any improved behaviour. An\nO(a^2) on-shell improved action with all couplings defined on a plaquette and\nsatisfying reflection positivity is also explicitly constructed."
    },
    {
        "anchor": "B decays on the lattice: I review recent developments in lattice calculations of B decay matrix\nelements and other related quantities.",
        "positive": "Improved lattice operators: the case of the topological charge density: We analyze the properties of a class of improved lattice topological charge\ndensity operators, constructed by a smearing-like procedure. By optimizing the\nchoice of the parameters introduced in their definition, we find operators\nhaving (i) a better statistical behavior as estimators of the topological\ncharge density on the lattice, i.e. less noisy; (ii) a multiplicative\nrenormalization much closer to one; (iii) a large suppression of the\nperturbative tail (and other unphysical mixings) in the corresponding lattice\ntopological susceptibility."
    },
    {
        "anchor": "Multichannel 0-to-2 and 1-to-2 transition amplitudes for arbitrary spin\n  particles in a finite volume: We present a model-independent, non-perturbative relation between\nfinite-volume matrix elements and infinite-volume\n$\\textbf{0}\\rightarrow\\textbf{2}$ and $\\textbf{1}\\rightarrow\\textbf{2}$\ntransition amplitudes. Our result accommodates theories in which the final\ntwo-particle state is coupled to any number of other two-body channels, with\nall angular momentum states included. The derivation uses generic, fully\nrelativistic field theory, and is exact up to exponentially suppressed\ncorrections in the lightest particle mass times the box size. This work\ndistinguishes itself from previous studies by accommodating particles with any\nintrinsic spin. To illustrate the utility of our general result, we discuss how\nit can be implemented for studies of\n$N+\\mathcal{J}~\\rightarrow~(N\\pi,N\\eta,N\\eta',\\Sigma K,\\Lambda K)$ transitions,\nwhere $\\mathcal{J}$ is a generic external current. The reduction of rotational\nsymmetry, due to the cubic finite volume, manifests in this example through the\nmixing of S- and P-waves when the system has nonzero total momentum.",
        "positive": "Confinement in high-temperature lattice gauge theories: There has been substantial progress in understanding a class of SU(N) gauge\ntheories that are confining at high temperatures. This class includes theories\nwith center-symmetric Polyakov loop deformations or with periodic adjoint\nfermions. The crucial role of monopoles in lattice gauge theories of this type\ncan be understood analytically. The basic mechanisms occur in the\ntwo-dimensional O(3) spin model, deformed by appropriate mass term to give an\nXY model. Vortices of the XY model are constituents of O(3) instantons just as\nSU(N) magnetic monopoles are constituents of KvBLL instantons. Similar methods\napplied to an SU(2) lattice gauge theory yield an effective U(1) description in\nwhich monopoles are responsible for confinement."
    },
    {
        "anchor": "Heavy-meson semileptonic decays for the Standard Model and beyond: We calculate the form factors for the semileptonic decays $B_s\\to K\\ell\\nu$\nand $B\\to K\\ell\\ell$ with lattice QCD. We work at several lattice spacings and\na range of light quark masses, using the MILC 2+1-flavor asqtad ensembles. We\nuse the Fermilab method for the $b$ quark. We obtain chiral-continuum\nextrapolations for $E_K$ up to $\\sim1.2$ GeV and then extend to the entire\nkinematic range with the model-independent $z$ expansion.",
        "positive": "Light scalars in strongly-coupled extra-dimensional theories: The low-energy dynamics of five-dimensional Yang-Mills theories compactified\non S^1 can be described by a four-dimensional gauge theory coupled to a scalar\nfield in the adjoint representation of the gauge group. Perturbative\ncalculations suggest that the mass of this elementary scalar field is protected\nagainst power divergences, and is controlled by the size of the extra dimension\nR. As a first step in the study of this phenomenon beyond perturbation theory,\nwe investigate the phase diagram of a SU(2) Yang-Mills theory in five\ndimensions regularized on anisotropic lattices and we determine the ratios of\nthe relevant physical scales. The lattice system shows a dimensionally reduced\nphase where the four-dimensional correlation length is much larger than the\nsize of the extra dimension, but still smaller than the four-dimensional\nvolume. In this region of the bare parameter space, at energies below 1/R, the\nnon-perturbative spectrum contains a \\emph{light} scalar state. This state has\na mass that is independent of the cut-off, and a small overlap with glueball\noperators. Our results suggest that light scalar fields can be introduced in a\nlattice theory using compactified extra dimensions, rather than fine tuning the\nbare mass parameter."
    },
    {
        "anchor": "Can complex Langevin dynamics evade the sign problem?: I answer the question in the title for the relativistic Bose gas at finite\nchemical potential using numerical lattice simulations, complemented with\nanalytical understanding.",
        "positive": "Cost of Generalised HMC Algorithms for Free Field Theory: We study analytically the computational cost of the Generalised Hybrid Monte\nCarlo (GHMC) algorithm for free field theory. We calculate the autocorrelation\nfunctions of operators quadratic in the fields, and optimise the GHMC momentum\nmixing angle, the trajectory length, and the integration stepsize. We show that\nlong trajectories are optimal for GHMC, and that standard HMC is much more\nefficient than algorithms based on the Second Order Langevin (L2MC) or Kramers\nEquation. We show that contrary to naive expectations HMC and L2MC have the\nsame volume dependence, but their dynamical critical exponents are z=1 and\nz=3/2 respectively."
    },
    {
        "anchor": "Improving the Chiral Properties of Lattice Fermions: The chiral properties of lattice fermions can be improved by altering either\ntheir fermion-gauge coupling or the pure gauge part of the action (or both).\n  Using both perturbation theory and nonperturbative simulation, we compare a\nsimple alteration of the gauge action (which encompasses the Wilson, Symanzik,\nIwasaki, and DBW2 actions), and HYP-blocked links in the fermion action.\nPerturbative tests include calculations of the potential, flavor-changing quark\nscattering amplitudes, and matching factors for currents. Non-perturbative\ntests include the potential, measurements of flavor symmetry breaking for\nstaggered fermions, the behavior of topological objects, and properties of\noverlap actions. Our results display the bad properties of these actions as\nwell as their good ones.",
        "positive": "Clover fermions in the adjoint representation and simulations of\n  supersymmetric Yang-Mills theory: Clover improvement is the standard choice for lattice simulations of QCD,\nwhen the lattice artefacts coming from Wilson fermions have to be reduced.\nHowever, the clover improvement is not limited to QCD, but can be applied to a\nwider range of theories with fermions in higher representations of the gauge\ngroup SU(N), like the adjoint fermions required by supersymmetry or by\ntechnicolor theories. We present the calculation of the clover coefficient up\nto one loop order with standard perturbation theory for these models.\nApplications of clover fermions to supersymmetric Yang-Mills theory are also\ndiscussed."
    },
    {
        "anchor": "Implementation of C* boundary conditions in the Hybrid Monte Carlo\n  algorithm: In the study of QCD dynamics, C* boundary conditions are physically relevant\nin certain cases. In this paper we study the implementation of these boundary\nconditions in the lattice formulation of full QCD with staggered fermions. In\nparticular, we show that the usual even-odd partition trick to avoid the\nredoubling of the fermion matrix is still valid in this case. We give an\nexplicit implementation of these boundary conditions for the Hybrid Monte Carlo\nalgorithm.",
        "positive": "Improved Dirichlet boundary conditions for lattice gauge-fermion\n  theories: Hybrid Monte Carlo (HMC) simulations of lattice gauge theories with fermionic\nmatter rely on the invertibility of the lattice Dirac operator. Near-zero modes\nof the latter can therefore significantly slow down the update algorithm and\ncause instabilities. This is in particular a problem when dealing with massless\nfermions. Homogeneous temporal Dirichlet boundary conditions can be used to\nremove zero modes from massless lattice Dirac operators, but the standard\nimplementation of these boundary conditions can cause severe finite-volume\ncutoff effects in regions of parameter space where the physics at the\nultraviolet (UV) cutoff scale is dominated by the fermionic instead of the\ngauge action. In lattice quantum chromodynamics (QCD) this is usually not an\nissue, as the gauge action dominates the UV physics and the problem does not\nshow up. In studies of beyond standard model (BSM) theories, on the other hand,\nthe finite-volume artifacts can be severe. We have identified the origin of\nthese IR cutoff effects and propose a simple improvement on the homogeneous\ntemporal Dirichlet boundary conditions to prevent them. We demonstrate the\nbenefits of using our improved boundary conditions at the example of SU(2)\nlattice gauge theory with $N_f=24$ massless Wilson-clover flavors. Due to the\nlarge number of fermions in this theory, the boundary-related finite volume\nartifacts are particularly strong, and the effect from switching from the\nnormal to our improved homogeneous Dirichlet boundary conditions is therefore\ndistinct."
    },
    {
        "anchor": "Monopoles and instantons in SU(2) lattice gauge theory: We investigate the monopole-instanton correlation in SU(2) lattice gauge\ntheory using a renormalisation group inspired smoothing technique. We look at\nthe properties of monopole clusters and their correlation with instantons.\nSince the action of the smoothed configurations is dominated by instantons we\ncompare the smoothed Monte Carlo lattices to artificially reconstructed\nconfigurations with the same instanton content but no other fluctuations. Both\nparallel and randomly rotated (in group space) instanton ensembles are\nconsidered.",
        "positive": "Comparative studies of the deformation techniques for the singular-drift\n  problem in the complex Langevin method: In application of the complex Langevin method to QCD at high density and low\ntemperature, the singular-drift problem occurs due to the appearance of\nnear-zero eigenvalues of the Dirac operator. In order to avoid this problem, we\nproposed to deform the Dirac operator in such a way that the near-zero\neigenvalues do not appear and to extrapolate the deformation parameter to zero\nfrom the available data points. Here we test three different types of\ndeformation in a simple large-$N$ matrix model, which undergoes an SSB due to\nthe phase of the fermion determinant, and compare them to see the consistency\nwith one another."
    },
    {
        "anchor": "Diagrammatic Strong Coupling Expansion of U(1) Lattice Model in Fourier\n  Basis: The transfer-matrix of U(1) lattice gauge theory is investigated in the field\nFourier space, the basis of which consists of the quantized currents on lattice\nlinks. Based on a lattice version of the current conservation, the\ntransfer-matrix elements are shown to be non-zero only between current-states\nthat differ in circulating currents inside plaquettes. In the strong coupling\nlimit, a series expansion is developed for the elements of the transfer-matrix,\nto which a diagrammatic representation based on the occurrence of virtual link\nand loop currents can be associated. With $g$ as the coupling, the weight of\neach virtual current in the expansion is $1/g^2$, by which at any given order\nthe relevant diagrams are determined. Either by interpretation or through their\nrole in fixing the relevant terms, the diagrams are reminiscent of the Feynman\nones of the perturbative small coupling expansions.",
        "positive": "Quenched KS light hadron mass at \u03b2=6.5 on a 64\\times 48^3 lattice: We report our quenched staggered light hadron mass calculation at the\ncoupling of \\beta = 6.5 on a 48^3 \\times 64 lattice, based on an increased\nstatistics of two hundred gauge configurations. Staggered quark wall sources\nwith mass of m_q a = 0.01, 0.005, 0.0025 and 0.00125 are used. Flavor symmetry\nis restored for pion and \\rho meson. The lattice scale is estimated to be\na^{-1} = 3.7(2) GeV."
    },
    {
        "anchor": "Finite density QCD with chiral invariant four-fermion interactions: A mean field analysis of finite density QCD is presented including the\neffects of additional chiral invariant four-fermion interactions. A lattice\nregularization is used with N_f=4 flavors of staggered fermions. The use of the\nfour-fermion coupling as an improved extrapolation parameter over the bare\nquark mass in Monte Carlo simulations is discussed. Particular attention is\ngiven to the structure of the phase diagram and the order of the chiral phase\ntransition. At zero gauge coupling, the model reduces to a Nambu-Jona-Lasinio\nmodel. In this limit the chiral phase transition is found to be second-order\nnear the zero-density critical point and otherwise first-order. In the strong\ngauge coupling limit a first-order chiral phase transition is found. In this\nlimit the additional four-fermion interactions do not qualitatively change the\nphysics. The results agree with previous studies of QCD as the four-fermion\ncoupling vanishes.",
        "positive": "Lepton anomalous magnetic moments from twisted mass fermions: We present our results for the leading-order hadronic quark-connected\ncontributions to the electron, the muon, and the tau anomalous magnetic moments\nobtained with four dynamical quarks. Performing the continuum limit and an\nanalysis of systematic effects, full agreement with phenomenological results is\nfound. To estimate the impact of omitting the quark-disconnected contributions\nto the hadronic vacuum polarisation we investigate them on one of the\nfour-flavour ensembles. Additionally, the light quark contributions on the\nfour-flavour sea are compared to the values obtained for $N_f=2$ physically\nlight quarks. In the latter case different methods to fit the hadronic vacuum\npolarisation function are tested."
    },
    {
        "anchor": "Novel quark smearing for hadrons with high momenta in lattice QCD: Hadrons in lattice QCD are usually created employing smeared interpolators.\nWe introduce a new quark smearing that allows us to maintain small statistical\nerrors and good overlaps of hadronic wavefunctions with the respective ground\nstates, also at high spatial momenta. The method is successfully tested for the\npion and the nucleon at a pion mass $m_{\\pi}\\approx 295$ MeV and momenta as\nhigh as 2.8 GeV. We compare the results obtained to dispersion relations and\nsuggest further optimizations.",
        "positive": "Persistent homology as a probe for center vortices and deconfinement in\n  SU(2) lattice gauge theory: Topological Data Analysis (TDA) is a field that leverages tools and ideas\nfrom algebraic topology to provide robust methods for analysing geometric and\ntopological aspects of data. One of the principal tools of TDA, persistent\nhomology, produces a quantitative description of how the connectivity and\nstructure of data changes when viewed over a sequence of scales. We propose\nthat this presents a means to directly probe topological objects in gauge\ntheories. We present recent work on using persistent homology to detect center\nvortices in SU(2) lattice gauge theory configurations in a gauge-invariant\nmanner. We introduce the basics of persistence, describe our construction, and\ndemonstrate that the result is sensitive to vortices. Moreover we discuss how,\nwith simple machine learning, one can use the resulting persistence to\nquantitatively analyse the deconfinement transition via finite-size scaling,\nproviding evidence on the role of vortices in relation to confinement in\nYang-Mills theories."
    },
    {
        "anchor": "A study of $O(1/m_{Q}^{2})$ corrections for $f_{B}$ with lattice NRQCD: We investigate higher order effects in the nonrelativistic expansion of\nlattice QCD on the heavy-light meson decay constants and some other quantities\nin order to understand the truncation error of NRQCD. While our numerical\nresults have large $O(a)$ and $O(\\alpha_s)$ errors due to the use of Wilson\nlight quark action and the tree-level matching, we find that the truncation\nerror of higher order relativistic corrections are adequately small around the\nmass of the $b$ quark. We also present a perturbatively matched results through\n1-loop level without operator mixing effects.",
        "positive": "Spinodal Decomposition in High Temperature Gauge Theories: After a rapid increase in temperature across the deconfinement temperature $%\nT_{d}$, pure gauge theories exhibit unstable long wavelength fluctuations in\nthe approach to equilibrium. This phenomenon is analogous to spinodal\ndecomposition observed in condensed matter physics, and also seen in models of\ndisordered chiral condensate formation. At high temperature, the unstable modes\noccur only in the range $0\\leq k$ $\\leq k_{c}$, where $k_{c}$ is on the order\nof the Debye screening mass $m_D$. Equilibration always occurs via spinodal\ndecomposition for $SU(2) $at temperatures $T>T_{d}$ and for SU(3) for $T\\gg\nT_{d}$. For SU(3) at temperatures $T\\gtrsim T_{d}$, nucleation may replace\nspinodal decomposition as the dominant equilibration mechanism. Monte Carlo\nsimulations of SU(2) lattice gauge theory exhibit the predicted phenomena. The\nobserved value of $k_c$ is in reasonable agreement with a value predicted from\nprevious lattice measurements of $m_D$."
    },
    {
        "anchor": "Finite Temperature Lattice QCD - Baryons in the Quark-Gluon Plasma: Baryonic correlation functions provide an ideal tool to study parity doubling\nand chiral symmetry using lattice simulations. We present a study using $2+1$\nflavors of anisotropic Wilson clover fermions on the FASTSUM ensembles and find\nclear evidence that parity doubling emerges in the quark-gluon plasma. This\nresult is confirmed on the level of spectral functions, which are obtained\nusing a MEM reconstruction. We further highlight the importance of Gaussian\nsmearing in this study.",
        "positive": "An Estimate of the K0-K0bar Mixing Amplitude: We computed the B_K parameter on the lattice by using a non-perturbatively\nimproved Wilson action. From our quenched simulation, in the MSbar scheme and\nat mu=2 GeV, we obtain B_K=0.73(7)^{+0.05}_{-0.01}. To gain some insight in the\nsystematic errors due to the use of the quenched approximation, we also made\nthe unquenched computation with Wilson fermions. We do not observe any\nsignificant deviation with respect to the quenched result."
    },
    {
        "anchor": "Pion vector and scalar form factors with dynamical overlap quarks: We calculate the pion vector and scalar form factors in two-flavor QCD. Gauge\nconfigurations are generated with dynamical overlap quarks on a 16^3 x 32\nlattice at a lattice spacing of 0.12 fm with sea quark masses down to a sixth\nof the physical strange quark mass. Contributions of disconnected diagrams to\nthe scalar form factor is calculated employing the all-to-all quark\npropagators. We present a detailed comparison of the vector and scalar radii\nwith chiral perturbation theory to two loops.",
        "positive": "On a modification method of Lefschetz thimbles: The QCD at finite density is not well understood yet, where standard Monte\nCarlo simulation suffers from the sign problem. In order to overcome the sign\nproblem, the method of Lefschetz thimble has been explored. Basically, the\noriginal sign problem can be less severe in a complexified theory due to the\nconstancy of the imaginary part of an action on each thimble. However, global\nphase factors assigned on each thimble still remain. Their interference is not\nnegligible in a situation where a large number of thimbles contribute to the\npartition function, and this could also lead to a sign problem.In this study,\nwe propose a method to resolve this problem by modifying the structure of\nLefschetz thimbles such that only a single thimble is relevant to the partition\nfunction. It can be shown that observables measured in the original and\nmodified theories are connected by a simple identity. We exemplify that our\nmethod works well in a toy model."
    },
    {
        "anchor": "Theoretical estimate of the $D^* \\to D\u03c0$ decay rate: We present the results of our lattice QCD study of the $g_{D^* D\\pi}i$\ncoupling, relevant to the $D^\\ast \\to D\\pi$ decay. Our computation is made on\nthe gauge field configurations that include $N_f=2$ dynamical light quarks by\nusing the twisted mass QCD action. From the results obtained at four different\nlattice spacings we were able to take for the first time the continuum limit of\nthis quantity computed on the lattice. Our final value, $g_c=0.53(3)(3)$, leads\nto $\\Gamma(D^{\\ast +}\\to \\bar{D}^0 \\pi^+)= (50\\pm 5\\pm 6)$ keV, and is in good\nagreement with the experimental results for the width of the charged\n$D^\\ast$-meson.",
        "positive": "Lattice QCD and the Computational Frontier: The search for new physics requires a joint experimental and theoretical\neffort. Lattice QCD is already an essential tool for obtaining precise\nmodel-free theoretical predictions of the hadronic processes underlying many\nkey experimental searches, such as those involving heavy flavor physics, the\nanomalous magnetic moment of the muon, nucleon-neutrino scattering, and rare,\nsecond-order electroweak processes. As experimental measurements become more\nprecise over the next decade, lattice QCD will play an increasing role in\nproviding the needed matching theoretical precision. Achieving the needed\nprecision requires simulations with lattices with substantially increased\nresolution. As we push to finer lattice spacing we encounter an array of new\nchallenges. They include algorithmic and software-engineering challenges,\nchallenges in computer technology and design, and challenges in maintaining the\nnecessary human resources. In this white paper we describe those challenges and\ndiscuss ways they are being dealt with. Overcoming them is key to supporting\nthe community effort required to deliver the needed theoretical support for\nexperiments in the coming decade."
    },
    {
        "anchor": "The sphaleron rate from Euclidean lattice correlators: an exploration: We show how the sphaleron rate (the Minkowski rate for topological charge\ndiffusion) can be determined by analytical continuation of the Euclidean\ntopological-charge-density two-point function, which we investigate on the\nlattice, using gradient flow to reduce noise and provide improved operators\nwhich more accurately measure topology. We measure the correlators on large,\nfine lattices in the quenched approximation at $1.5\\,T_c$ with high precision.\nBased on these data we first perform a continuum extrapolation at fixed\nphysical flow time and then extrapolate the continuum estimates to zero flow\ntime. The extrapolated correlators are then used to study the sphaleron rate by\nspectral reconstruction based on perturbatively motivated models.",
        "positive": "Majorana fermions and CP-invariance of chiral gauge theories on the\n  lattice: The construction of massless Majorana fermions with chiral Yukawa couplings\non the lattice is considered. We find topological obstructions tightly linked\nto those underlying the Nielsen-Ninomiya no-go theorem. In contradistinction to\nchiral fermions the obstructions originate only from the combination of the\nDirac action and the Yukawa term. These findings are used to construct a\nchirally invariant lattice action. We also show that the path integral of this\ntheory is given by the Pfaffian of the corresponding Dirac operator. As an\napplication of the approach set-up here we construct a CP-invariant lattice\naction of a chiral gauge theory, based on a lattice adaptation of charge\nconjugation and parity transformation in the continuum."
    },
    {
        "anchor": "Fermions in higher representations. Some results about SU(2) with\n  adjoint fermions: We discuss the lattice formulation of gauge theories with fermions in\narbitrary representations of the color group, and present the implementation of\nthe RHMC algorithm for simulating dynamical Wilson fermions. A first dataset is\npresented for the SU(2) gauge theory with two fermions in the adjoint\nrepresentation, which has been proposed as a possible technicolor candidate.\nSimulations are performed on 8^3x16 lattices, at fixed lattice spacing. The\nPCAC mass, the pseudoscalar, vector and axial meson masses, the pseudoscalar\nmeson decay constant are computed. The extrapolation to the chiral limit is\ndiscussed. However more extensive investigations are needed in order to control\nthe systematic errors in the numerical results, and then understand in detail\nthe phase structure of these theories.",
        "positive": "Suppressing monopoles and vortices : A possibly smoother approach to\n  scaling ?: Suppressing monopoles and vortices by introducing large chemical potentials\nfor them in the Wilson action for the SU(2) lattice gauge theory, we study the\nnature of the deconfinement phase transition on N_\\sigma^3 \\times N_\\tau\nlattices for N_\\tau = 4, 5, 6 and 8 and N_\\sigma = 8--16. Using finite size\nscaling theory, we obtain \\omega = 1.93 \\pm 0.03 for N_\\tau = 4, in excellent\nagreement with universality. Corresponding determinations for the N_\\tau = 5\nand 6 lattices are also found to be in very good agreement with this estimate.\nThe critical couplings for N_\\tau= 4, 5, 6 and 8 lattices exhibit large shifts\ntowards the strong coupling region when compared with the usual Wilson action,\nand suggest a lot smoother approach to scaling."
    },
    {
        "anchor": "Gauge Boson Masses in the 3-d, SU(2) Gauge-Higgs Model: We study gauge boson propagators in the symmetric and symmetry broken phases\nof the 3-d, $SU(2)$ gauge-Higgs model. Correlation functions for the gauge\nfields are calculated in Landau gauge. They are found to decay exponentially at\nlarge distances leading to a non-vanishing mass for the gauge bosons. We find\nthat the W-boson screening mass drops in the symmetry broken phase when\napproaching the critical temperature. In the symmetric phase the screening mass\nstays small and is independent of the scalar--gauge coupling (the hopping\nparameter). Numerical results coincide with corresponding calculations\nperformed for the pure gauge theory. We find $m_w = 0.35(1)g^2T $ in this phase\nwhich is consistent with analytic calculations based on gap equations. This is,\nhowever, significantly smaller than masses extracted from gauge invariant\nvector boson correlation functions. As internal consistency check we also have\ncalculated correlation functions for gauge invariant operators leading to\nscalar and vector boson masses. Finite lattice size effects have been\nsystematically analyzed on lattices of size $L^2\\times L_z$ with $L=4-24$ and\n$L_z = 16 - 128$.",
        "positive": "Thermodynamics of strong-interaction matter from Lattice QCD: We review results from lattice QCD calculations on the thermodynamics of\nstrong-interaction matter with emphasis on input these calculations can provide\nto the exploration of the phase diagram and properties of hot and dense matter\ncreated in heavy ion experiments. This review is organized as follows: 1)\nIntroduction, 2) QCD thermodynamics on the lattice, 3) QCD phase diagram at\nhigh temperature, 4) Bulk thermodynamics, 5) Fluctuations of conserved charges,\n6) Transport properties, 7) Open heavy flavors and heavy quarkonia, 8) QCD in\nexternal magnetic fields, 9) Summary."
    },
    {
        "anchor": "Local Observables in $\\operatorname{SU}_q(2)$ Lattice Gauge Theory: We consider a deformation of 3D lattice gauge theory in the canonical\npicture, first classically, based on the Heisenberg double of\n$\\operatorname{SU}(2)$, then at the quantum level. We show that classical\nspinors can be used to define a fundamental set of local observables. They are\ninvariant quantities which live on the vertices of the lattice and are labelled\nby pairs of incident edges. Any function on the classical phase space, e.g.\nWilson loops, can be rewritten in terms of these observables. At the quantum\nlevel, we show that spinors become spinor operators. The quantization of the\nlocal observables then requires the use of the quantum $\\mathcal{R}$-matrix\nwhich we prove to be equivalent to a specific parallel transport around the\nvertex. We provide the algebra of the local observables, as a Poisson algebra\nclassically, then as a $q$-deformation of $\\mathfrak{so}^*(2n)$ at the quantum\nlevel. This formalism can be relevant to any theory relying on lattice gauge\ntheory techniques such as topological models, loop quantum gravity or of course\nlattice gauge theory itself.",
        "positive": "Non-analyticity of the Callan-Symanzik beta-function of O(N) models: In the framework of the 1/N-expansion we show that the Callan-Symanzik beta-\nfunction associated with the four-point coupling g is non-analytic at its zero,\ni.e. at the fixed-point value g^* of g. This behavior can be interpreted by\nrenormalization group arguments, and written in terms of scaling correction\nexponents. We obtain accurate determinations of g^* in 3-d and 2-d by\nexploiting two alternative approaches: the (4-d)-expansion and the\nhigh-temperature expansion. These results are compared with the available\nestimates by other approaches, such as the fixed-dimension perturbative\nexpansion, Monte Carlo simulations, etc... We also present results for the\nn-point renormalized coupling constants that parameterize the behavior of the\neffective potential in the high- and low- temperature phases."
    },
    {
        "anchor": "The electroweak phase transition: a non-perturbative lattice\n  investigation: We present results obtained from a numerical investigation of the electroweak\nphase transition in the SU(2)-Higgs model. The simulations are performed at two\nvalues of the Higgs boson mass, $M_H\\approx 20$ GeV and $M_H\\approx 50$ GeV.\nWhile the phase transition is of strongly first order at the smaller value of\nthe Higgs mass it weakens rapidly when the Higgs mass is increased. This is in\nqualitative agreement with perturbation theory as the comparison of various\nphysical quantities shows.",
        "positive": "Quark Confinement Physics from Lattice QCD: We study quark confinement physics using lattice QCD. In the maximally\nabelian (MA) gauge, the off-diagonal gluon amplitude is strongly suppressed,\nand then the off-diagonal gluon phase shows strong randomness, which leads to a\nlarge effective off-diagonal gluon mass, M_off=1.2GeV. Due to the large\noff-diagonal gluon mass in the MA gauge, low-energy QCD is abelianized like\nnonabelian Higgs theories. In the MA gauge, there appears a macroscopic network\nof the monopole world-line covering the whole system. We extract and analyze\nthe dual gluon field B_mu from the monopole-current system in the MA gauge, and\nevaluate the dual gluon mass as m_B = 0.4-0.5GeV in the infrared region, which\nis a lattice-QCD evidence of the dual Higgs mechanism by monopole condensation.\nEven without explicit use of gauge fixing, we can define the maximal abelian\nprojection by introducing a ``gluonic Higgs field'' phi(x), whose hedgehog\nsingularities lead to monopoles. From infrared abelian dominance and infrared\nmonopole condensation, infrared QCD is describable with the dual\nGinzburg-Landau theory. In relation to the color-flux-tube picture for baryons,\nwe study the three-quark (3Q) ground-state potential V_3Q in SU(3) lattice QCD\nat the quenched level, with the smearing technique for enhancement of the\nground-state component. With accuracy better than a few %, V_3Q is well\ndescribed by a sum of the two-body Coulomb part and the three-body linear\nconfinement part sigma_3Q L_min, where L_min denotes the minimal value of the\ntotal length of the color flux tube linking the three quarks. Comparing with\nthe Q-barQ potential, we find a universal feature of the string tension and the\nOGE result for the Coulomb coefficient."
    },
    {
        "anchor": "Systematic study of the completeness of two-dimensional classical\n  $\u03c6^4$ theory: The completeness of some classical statistical mechanical (SM) models is a\nrecent result that has been developed by quantum formalism for the partition\nfunctions. In this paper, we consider a 2D classical $\\phi^4$ filed theory\nwhose completeness has been proved in [V. Karimipour and et al, Phys. Rev. A\n85, 032316]. We give a general systematic proof for the completeness of such a\nmodel where, by a few simple steps, we show how the partition function of an\narbitrary classical field theory can be derived from a 2D classical $\\phi^4$\nmodel. To this end, we start from various classical field theories containing\nmodels on arbitrary lattices and also $U(1)$ lattice gauge theories. Then we\nconvert them to a new classical field model on a non-planar bipartite graph\nwith imaginary kinetic terms. After that, we show that any polynomial function\nof the field in the corresponding Hamiltonian can approximately be converted to\na $\\phi^4$ term by adding enough numbers of vertices to the bipartite graph. In\nthe next step, we give a few graphical transformations to convert the final\nnon-planar graph to a 2D rectangular lattice. We also show that the number of\nvertices which should be added grows polynomially with the number of vertices\nin the original model.",
        "positive": "Improved thermodynamics of SU(2) gauge theory: In this work we present the results of our investigation about the\nthermodynamics of SU(2) gauge theory. We employ a Symanzik improved action to\nreduce strongly the discretisations effects, and we use the scaling relations\nto take into account the finite volume effects close to the critical\ntemperature. We determine the beta-function for this particular theory and we\nuse it in the determination of different thermodynamic observables. Finally we\ncompare our results with previous works where only the standard Wilson action\nwas considered. We confirm the relevance of using the improved action to access\neasily the correct continuum thermodynamics of the theory."
    },
    {
        "anchor": "Dual superconductivity in the SU(2) pure gauge vacuum: a lattice study: We investigate the dual superconductivity hypothesis in pure SU(2) lattice\ngauge theory. We focus on the dual Meissner effect by analyzing the\ndistribution of the color fields due to a static quark-antiquark pair. We find\nevidence of the dual Meissner effect both in the maximally Abelian gauge and\nwithout gauge fixing. We measure the London penetration length. Our results\nsuggest that the London penetration length is a physical gauge-invariant\nquantity. We put out a simple relation between the penetration length and the\nsquare root of the string tension. We find that our extimation is quite close\nto the extrapolated continuum limit available in the literature. A remarkable\nconsequence of our study is that an effective Abelian theory can account for\nthe long range properties of the SU(2) confining vacuum.",
        "positive": "Chiral symmetry breaking and the generation of light hadron masses: A quantitative study of the effects of dynamical chiral symmetry breaking on\nthe mass generation of the low-lying hadrons in a dynamical lattice QCD\nsimulation is presented. The evolution of light hadron masses upon increasing\nthe number of low-lying Dirac operator eigenmodes in the quark propagators is\nconfronted with the hadron masses obtained upon removal of such low-lying\neigenmodes from standard full quark propagators. The low-lying chiral symmetry\nbreaking modes provide roughly two third of the nucleon and $\\rho$ masses,\nwhile the $a_1$ mass is affected to a much smaller degree."
    },
    {
        "anchor": "Bound state spectrum in the finite volume: The signature of bound state formation on the lattice is of particular\ninterest in this talk. In the finite volume, where all states have discrete\nenergies, it is rather hard to distinguish between a bound state and a\nscattering state if the bound state were close to threshold, i.e., like a\n\"loosely bound state\". To study bound states in the finite volume, we calculate\nthe positronium spectroscopy in the Higgs phase of U(1) gauge dynamics, where\nthe photon is massive and then massive photons give rise to the short-ranged\ninterparticle force. We try to identify bound state formation on the basis of\nthe Luscher's finite size method, which suggests specific volume dependences of\nthe energy gap/shift from the threshold energy for either bound states or\nscattering states.",
        "positive": "Strong CP problem, electric dipole moment, and fate of the axion: Three hard problems! In this talk I investigate the long-distance properties\nof quantum chromodynamics in the presence of a topological theta term. This is\ndone on the lattice, using the gradient flow to isolate the long-distance modes\nin the functional integral measure and tracing it over successive length\nscales. It turns out that the color fields produced by quarks and gluons are\nscreened, and confinement is lost, for vacuum angles theta > 0, thus providing\na natural solution of the strong CP problem. This solution is compatible with\nrecent lattice calculations of the electric dipole moment of the neutron, while\nit excludes the axion extension of the Standard Model."
    },
    {
        "anchor": "Renormalization of the energy-momentum tensor in three-dimensional\n  scalar $SU(N)$ theories using the Wilson flow: A nonperturbative determination of the energy-momentum tensor is essential\nfor understanding the physics of strongly coupled systems. The ability of the\nWilson flow to eliminate divergent contact terms makes it a practical method\nfor renormalizing the energy-momentum tensor on the lattice. In this paper, we\nutilize the Wilson flow to define a procedure to renormalize the\nenergy-momentum tensor for a three-dimensional massless scalar field in the\nadjoint of $SU(N)$ with a $\\varphi^4$ interaction on the lattice. In this\ntheory the energy-momentum tensor can mix with $\\varphi^2$ and we present\nnumerical results for the mixing coefficient for the $N=2$ theory.",
        "positive": "The role of the Polyakov loop in finite density QCD: We study the behavior of the fermion determinant at finite temperature and\nchemical potential, as a function of the Polyakov loop. The phase of the\ndeterminant is correlated with the imaginary part of the Polyakov loop. This\ncorrelation and its consequences are considered in static QCD, in a toy model\nof free quarks in a constant $A_0$ background, and in simulations constraining\nthe imaginary part of the Polyakov loop to zero."
    },
    {
        "anchor": "Quark helicity flip generalized parton distributions from two-flavor\n  lattice QCD: We present an initiatory study of quark helicity flip generalized parton\ndistributions (GPDs) in n_f=2 lattice QCD, based on clover-improved Wilson\nfermions for a large number of coupling constants and pion masses. Quark\nhelicity flip GPDs yield essential information on the transverse spin structure\nof the nucleon. In this work, we show first results on their lowest moments and\ndipole masses and study the corresponding chiral and continuum extrapolations.",
        "positive": "Avoiding the sign-problem in lattice field theory: In lattice field theory, the interactions of elementary particles can be\ncomputed via high-dimensional integrals. Markov-chain Monte Carlo (MCMC)\nmethods based on importance sampling are normally efficient to solve most of\nthese integrals. But these methods give large errors for oscillatory\nintegrands, exhibiting the so-called sign-problem. We developed new quadrature\nrules using the symmetry of the considered systems to avoid the sign-problem in\nphysical one-dimensional models for the resulting high-dimensional integrals.\nThis article gives a short introduction to integrals used in lattice QCD where\nthe interactions of gluon and quark elementary particles are investigated,\nexplains the alternative integration methods we developed and shows results of\napplying them to models with one physical dimension. The new quadrature rules\navoid the sign-problem and can therefore be used to perform simulations at\nuntil now not reachable regions in parameter space, where the MCMC errors are\ntoo big for affordable sample sizes. However, it is still a challenge to\ndevelop these techniques further for applications with physical\nhigher-dimensional systems."
    },
    {
        "anchor": "Improvements of L\u00fcscher's local bosonic fermion algorithm: We discuss the application of hybrid over-relaxation, even-odd\npreconditioning and a modified local updating procedure to the local bosonic\nfermion algorithm. Studies on autocorrelation times and the tuning of the\nparameters of the algorithm are done on various lattice sizes simulating\nSU(2)-LGT with 2 flavours of Wilson quarks. A substantial decrease of the\ncomputational cost could be achieved.",
        "positive": "Effective potentials, thermodynamics, and twisted mass quarks: Using effective Lagrangian arguments, I explore the qualitative behavior\nexpected at finite temperature for two flavor lattice QCD formulated with\nWilson fermions and a twisted mass term. A rather rich phase structure is\npredicted, exhibiting Aoki's parity violating phase along with a deconfinement\nregion forming a conical structure in the space of coupling, hopping parameter,\nand twisted mass variables."
    },
    {
        "anchor": "Strange and charm contributions to nucleon charges and moments: We present preliminary results for strange and charm contributions to nucleon\ncharges and moments. The scalar, axial and tensor charges, and unpolarized\nfirst moments are calculated using clover-on-HISQ formulation and cover four\nlattice spacings, $a=\\{0.06,0.09,0.12, 0.15\\}$~fm, and three pion masses,\n$M_\\pi=\\{310,220,130\\}$~MeV. The renormalization factors are calculated\nnonperturbatively using the RI-sMOM scheme. We carry out a chiral and continuum\nextrapolation to obtain physical results.",
        "positive": "Structure-Dependent Electromagnetic Finite-Size Effects: We present a model-independent and relativistic approach to analytically\nderive electromagnetic finite-size effects beyond the point-like approximation.\nThe key element is the use of electromagnetic Ward identities to constrain\nvertex functions, and structure-dependence appears via physical form-factors\nand their derivatives. We apply our general method to study the leading\nfinite-size structure-dependence in the pseudoscalar mass (at order $1/L^3$) as\nwell as in the leptonic decay amplitudes of pions and kaons (at order $1/L^2$).\nKnowledge of the latter is essential for Standard Model precision tests in the\nflavour physics sector from lattice simulations."
    },
    {
        "anchor": "Baryon magnetic moments: Symmetries and relations: Magnetic moments of the octet baryons are computed using lattice QCD in\nbackground magnetic fields, including the first treatment of the magnetically\ncoupled Sigma-Lambda system. Although the computations are performed for\nrelatively large values of the up and down quark masses, we gain new insight\ninto the symmetries and relations between magnetic moments by working at a\nthree-flavor mass-symmetric point. While the spin-flavor symmetry in the large\nNc limit of QCD is shared by the naive constituent quark model, we find\ninstances where quark model predictions are considerably favored over those\nemerging in the large Nc limit. We suggest further calculations that would shed\nlight on the curious patterns of baryon magnetic moments.",
        "positive": "Topological lumps and Dirac zero modes in SU(3) lattice gauge theory on\n  the torus: We compute eigenmodes of the lattice Dirac operator for quenched SU(3) gauge\nconfigurations on the 4-torus with topological charge 1. We find a strong\ndependence of the zero modes on the boundary conditions which we impose for the\nDirac operator. The lumps seen by the eigenmodes often change their position\nwhen changing the boundary conditions, while the local chirality of the lumps\nremains the same. Our results show that the zero mode of a charge 1\nconfiguration can couple to more than one object. We address the question\nwhether these objects could be fractionally charged lumps."
    },
    {
        "anchor": "Four Quarks from Lattice to the Continuum: A continuum extrapolation of static four- and two-quark energies calculated\nin quenched SU(2) is done based on Sommer's method of setting the scale. A\nmodel for four-quark energies with explicit gluonic degrees of freedom removed\nis fitted to these energies and the behavior of the parameters of the model is\ninvestigated.",
        "positive": "Phase transition and topology in 4d simplicial gravity: We present data indicating that the recent evidence for the phase transition\nbeing of first order does not result from a breakdown of the ergodicity of the\nalgorithm. We also present data showing that the thermodynamical limit of the\nmodel is independent of topology."
    },
    {
        "anchor": "Quenching Effects in the Hadron Spectrum: Lattice QCD has generated a wealth of data in hadronic physics over the last\ntwo decades. Until relatively recently, most of this information has been\nwithin the \"quenched approximation\" where virtual quark--anti-quark pairs are\nneglected. This review presents a descriptive discussion of the effects of\nremoving this approximation in the calculation of hadronic masses.",
        "positive": "Fine structure of the confining string in an analytically solvable 3D\n  model: In $\\mathrm{U(1)}$ lattice gauge theory in three spacetime dimensions,\nconfinement can be analytically shown to persist at all values of the coupling.\nFurthermore, the explicit predictions for the dependence of string tension\n$\\sigma$ and mass gap $m_0$ on the coupling allow one to tune their ratio at\nwill. These features, and the possibility of obtaining high-precision numerical\nresults via an exact duality map to a spin model, make this theory an ideal\nlaboratory to test the effective string description of confining flux tubes. In\nthis contribution, we discuss our investigation of next-to-leading-order\ncorrections to the confining potential and of the finite-temperature behavior\nof the flux tube width. Our data provide a very stringent test of the\ntheoretical predictions for these quantities and allow to test their dependence\non the $m_0/\\sqrt{\\sigma}$ ratio."
    },
    {
        "anchor": "Log-enhanced discretization errors in integrated correlation functions: Integrated time-slice correlation functions $G(t)$ with weights $K(t)$\nappear, e.g., in the moments method to determine $\\alpha_s$ from heavy quark\ncorrelators, in the muon g-2 determination or in the determination of smoothed\nspectral functions.\n  For the (leading-order-)normalised moment $R_4$ of the pseudo-scalar\ncorrelator we have non-perturbative results down to $a=10^{-2}$ fm and for\nmasses, $m$, of the order of the charm mass in the quenched approximation. A\nsignificant bending of $R_4$ as a function of $a^2$ is observed at small\nlattice spacings.\n  Starting from the Symanzik expansion of the integrand we derive the\nasymptotic convergence of the integral at small lattice spacing in the free\ntheory and prove that the short distance part of the integral leads to\n$\\log(a)$-enhanced discretisation errors when $G(t)K(t) \\sim\\, t $ for small\n$t$. In the interacting theory an unknown, function $K(a\\Lambda)$ appears.\n  For the $R_4$-case, we modify the observable to improve the short distance\nbehavior and demonstrate that it results in a very smooth continuum limit. The\nstrong coupling and the $\\Lambda$-parameter can then be extracted. In general,\nand in particular for $g-2$, the short distance part of the integral should be\ndetermined by perturbation theory. The (dominating) rest can then be obtained\nby the controlled continuum limit of the lattice computation.",
        "positive": "Nucleon form factors and O(a) Improvement: Nucleon form factors have been extensively studied both experimentally and\ntheoretically for many years. We report here on new results of a high\nstatistics quenched lattice QCD calculation of vector and axial-vector nucleon\nform factors at low momentum transfer within the Symanzik improvement\nprogramme. The simulations are performed at three kappa and three beta values\nallowing first an extrapolation to the chiral limit and then an extrapolation\nin the lattice spacing to the continuum limit. The computations are all fully\nnon-perturbative. A comparison with experimental results is made."
    },
    {
        "anchor": "Topological observables in many-flavour QCD: SU(3) gauge theory with eight massless flavours is believed to be walking,\nwhile the corresponding twelve- and four-flavour appear IR-conformal and\nconfining respectively. Looking at the simulations performed by the LatKMI\ncollaboration of these theories, we use the topological susceptibility as an\nadditional probe of the IR dynamics. By drawing a comparison with SU(3) pure\ngauge theory, we see a dynamical quenching effect emerge at larger number of\nflavours, which is suggestive of emerging near-conformal and conformal\nbehaviour.",
        "positive": "Quark Masses from Lattice QCD: In this talk I review several topics concerning the determination of quark\nmasses by means of lattice QCD simulations, with particular focus on recently\nintroduced techniques of non-perturbative renormalisation, the determination of\nheavy quark masses, and the proper quantification of the source of isospin\nbreaking effects in the light quark sector."
    },
    {
        "anchor": "Simulations of Cold Electroweak Baryogenesis: Cold Electroweak Baryogenesis is an attempt to explain the cosmological\nbaryon asymmetry using only a minimal extension of the Standard Model. The\nrelevant processes take place out of thermal equilibrium and are\nnon-perturbative, and so must be studied using full, real-time lattice\nsimulations. We present new results on the dependence on CP-violation and the\nHiggs-to-W-mass ratio",
        "positive": "Phase transition(s) in finite density QCD: The Grand Canonical formalism is generally used in numerical simulations of\nfinite density QCD since it allows free mobility in the chemical potential\n$\\mu$. We show that special care has to be used in extracting numerical results\nto avoid dramatic rounding effects and spurious transition signals. If we\nanalyze data correctly, with reasonable statistics, no signal of first order\nphase transition is present and results using the Glasgow prescription are\npractically coincident with the ones obtained using the modulus of the\nfermionic determinant."
    },
    {
        "anchor": "Massive Fermions in Lattice Gauge Theory: This paper presents a formulation of lattice fermions applicable to all quark\nmasses, large and small. We incorporate interactions from previous\nlight-fermion and heavy-fermion methods, and thus ensure a smooth connection to\nthese limiting cases. The couplings in improved actions are evaluated for\narbitrary fermion mass~$m_q$, without expansions around small- or large-mass\nlimits. We treat both the action and external currents. By interpreting\non-shell improvement criteria through the lattice theory's Hamiltonian, one\nfinds that cutoff artifacts factorize into the form\n$b_n(m_qa)[\\vek{p}a]^{s_n}$, where $\\vek{p}$ is a momentum characteristic of\nthe system under study, $s_n$ is related to the dimension of the $n$th\ninteraction, and $b_n(m_qa)$ is a bounded function, numerically\nalways~$\\order(1)$ or less. In heavy-quark systems $\\vek{p}$ is typically\nrather smaller than the fermion mass~$m_q$. Therefore, artifacts of order\n$(m_qa)^s$ do not arise, even when $m_qa\\gsim1$. An important by-product of our\nanalysis is an interpretation of the Wilson and Sheikholeslami-Wohlert actions\napplied to nonrelativistic fermions.",
        "positive": "Recent results using all-point quark propagators: Pseudofermion methods for extracting all-point quark propagators are\nreviewed, with special emphasis on techniques for reducing or eliminating\nautocorrelations induced by low eigenmodes of the quark Dirac operator. Recent\napplications, including high statistics evaluations of hadronic current\ncorrelators and the pion form factor, are also described."
    },
    {
        "anchor": "Topological Zero Modes in Monte Carlo Simulations: We present an improvement of global Metropolis updating steps, the instanton\nhits, used in a hybrid Monte Carlo simulation of the two-flavor Schwinger model\nwith staggered fermions. These hits are designed to change the topological\nsector of the gauge field. In order to match these hits to an unquenched\nsimulation with pseudofermions, the approximate zero mode structure of the\nlattice Dirac operator has to be considered explicitly.",
        "positive": "Lattice Formulation of ${\\cal N} = 2^*$ Yang-Mills: We formulate ${\\cal N} = 2^*$ supersymmetric Yang-Mills theory on a Euclidean\nspacetime lattice using the method of topological twisting. The lattice\nformulation preserves one scalar supersymmetry charge at finite lattice\nspacing. The lattice theory is also local, gauge invariant and free from\ndoublers. We can use the lattice formulation of ${\\cal N} = 2^*$ supersymmetric\nYang-Mills to study finite temperature nonperturbative sectors of the theory\nand thus validate the gauge-gravity duality conjecture in a nonconformal\ntheory."
    },
    {
        "anchor": "On the influence of colour magnetic currents on the confining properties\n  of SU(3) lattice gauge theory: We modify the standard Wilson action of SU(3) lattice gauge theory by adding\nan extra term which suppresses colour magnetic currents. We present numerical\nresults of simulations at zero and finite temperature and show that colour\nmagnetic currents strongly influence the confining properties of SU(3) lattice\ngauge theory.",
        "positive": "Phase structure of the N=1 supersymmetric Yang-Mills theory at finite\n  temperature: Supersymmetry (SUSY) has been proposed to be a central concept for the\nphysics beyond the standard model and for a description of the strong\ninteractions in the context of the AdS/CFT correspondence. A deeper\nunderstanding of these developments requires the knowledge of the properties of\nsupersymmetric models at finite temperatures. We present a Monte Carlo\ninvestigation of the finite temperature phase diagram of the N=1 supersymmetric\nYang-Mills theory (SYM) regularised on a space-time lattice. The model is in\nmany aspects similar to QCD: quark confinement and fermion condensation occur\nin the low temperature regime of both theories. A comparison to QCD is\ntherefore possible. The simulations show that for N=1 SYM the deconfinement\ntemperature has a mild dependence on the fermion mass. The analysis of the\nchiral condensate susceptibility supports the possibility that chiral symmetry\nis restored near the deconfinement phase transition."
    },
    {
        "anchor": "Charmonium properties from lattice QCD + QED: hyperfine splitting,\n  $J/\u03c8$ leptonic width, charm quark mass and $a_\u03bc^c$: We have performed the first $n_f = 2+1+1$ lattice QCD computations of the\nproperties (masses and decay constants) of ground-state charmonium mesons. Our\ncalculation uses the HISQ action to generate quark-line connected two-point\ncorrelation functions on MILC gluon field configurations that include $u/d$\nquark masses going down to the physical point, tuning the $c$ quark mass from\n$M_{J/\\psi}$ and including the effect of the $c$ quark's electric charge\nthrough quenched QED. We obtain $M_{J/\\psi}-M_{\\eta_c}$ (connected) =\n120.3(1.1) MeV and interpret the difference with experiment as the impact on\n$M_{\\eta_c}$ of its decay to gluons, missing from the lattice calculation. This\nallows us to determine $\\Delta M_{\\eta_c}^{\\mathrm{annihiln}}$ =+7.3(1.2) MeV,\ngiving its value for the first time. Our result of $f_{J/\\psi}=$ 0.4104(17)\nGeV, gives $\\Gamma(J/\\psi \\rightarrow e^+e^-)$=5.637(49) keV, in agreement\nwith, but now more accurate than experiment. At the same time we have improved\nthe determination of the $c$ quark mass, including the impact of quenched QED\nto give $\\overline{m}_c(3\\,\\mathrm{GeV})$ = 0.9841(51) GeV. We have also used\nthe time-moments of the vector charmonium current-current correlators to\nimprove the lattice QCD result for the $c$ quark HVP contribution to the\nanomalous magnetic moment of the muon. We obtain $a_{\\mu}^c = 14.638(47) \\times\n10^{-10}$, which is 2.5$\\sigma$ higher than the value derived using moments\nextracted from some sets of experimental data on $R(e^+e^- \\rightarrow\n\\mathrm{hadrons})$. This value for $a_{\\mu}^c$ includes our determination of\nthe effect of QED on this quantity, $\\delta a_{\\mu}^c = 0.0313(28) \\times\n10^{-10}$.",
        "positive": "Phase structure of CP(N-1) model with topological term: CP(N-1) model with topological term is numerically studied. The topological\ncharge distribution P(Q) is calculated and then transformed to the partition\nfunction Z($\\theta$) as a function of $\\theta$ parameter. In the strong\ncoupling region, P(Q) shows a gaussian behavior, which indicates a first order\nphase transition at $\\theta =\\pi$. In the weak coupling region,\n  P(Q) deviates from gaussian. A bending behavior of resulting F($\\theta$) at\n$\\theta \\neq \\pi$, which might be a signal of a first order phase transition,\ncould be misled by large errors coming from the fourier transform of P(Q).\nResults are shown mainly for CP(3) case."
    },
    {
        "anchor": "Scale setting for $N_f=3+1$ QCD: We present the scale setting for a new set of gauge configurations generated\nwith $N_f=3+1$ Wilson quarks with a non-perturbatively determined clover\ncoefficient in a massive O($a$) improvement scheme. The three light quarks are\ndegenerate, with the sum of their masses being equal to its value in nature and\nthe charm quark has its physical mass. We use open boundary conditions in time\ndirection to avoid the problem of topological freezing at small lattice\nspacings and twisted-mass reweighting for improved stability of the\nsimulations. The decoupling of charm at low energy allows us to set the scale\nby measuring the value of the low-energy quantity $t_0^\\star/a^2$, which is the\nflow scale $t_0$ at our mass point, and comparing it to an $N_f=2+1$ result in\nphysical units. We present the details of the algorithmic setup and tuning\nprocedure and give the bare parameters of ensembles with two lattice spacings\na=0.054 fm and a=0.043 fm. We discuss finite volume effects and lattice\nartifacts and present physical results for the charmonium spectrum. In\nparticular the hyperfine splitting between the $\\eta_c$ and $J/\\psi$ mesons\nagrees very well with its physical value.",
        "positive": "Lattice Fermions Coupled to Interpolated Gauge Fields - Results in 2\n  Dimensions: We discuss a new approach for putting gauge theories on the lattice. The\ngauge fields are defined on the lattice only, but are interpolated to the\ninterior of the lattice cells, where they couple to continuum fermions. The\npurpose of this approach is to avoid doublers and keep the chiral symmetry of\nthe action intact. In two dimensional models (Schwinger model and chiral\nSchwinger model) many results for this hybrid approach can be obtained\nanalytically. For the vectorlike Schwinger model we concentrate on proving the\nexistence of a critical point where the continuum limit can be constructed, on\nanalyzing the chiral properties and on proving the Osterwalder-Schrader\npositivity which allows the reconstruction of the physical Hilbert space. We\nconclude with outlining how the results can be generalized to the chiral\nSchwinger model."
    },
    {
        "anchor": "Non-perturbative renormalisation of four fermion operators and B-bar B\n  mixing with Wilson fermions: We present new results for the renormalisation and subtraction constants for\nthe four fermion Delta F=2 operators, computed non-perturbatively in the RI-MOM\nscheme (in the Landau gauge). From our preliminary analysis of the lattice data\nat beta=6.45, for the B-bar B mixing bag-parameter we obtain B_B^{RGI} =\n1.46(7)(1).",
        "positive": "Determination of $s$- and $p$-wave $I=1/2$ $K\u03c0$ scattering amplitudes\n  in $N_{\\mathrm{f}}=2+1$ lattice QCD: The elastic $I=1/2$, $s$- and $p$-wave kaon-pion scattering amplitudes are\ncalculated using a single ensemble of anisotropic lattice QCD gauge field\nconfigurations with $N_{\\mathrm{f}} = 2+1$ flavors of dynamical Wilson-clover\nfermions at $m_{\\pi} = 230\\mathrm{MeV}$. A large spatial extent of $L =\n3.7\\mathrm{fm}$ enables a good energy resolution while partial wave mixing due\nto the reduced symmetries of the finite volume is treated explicitly.The\n$p$-wave amplitude is well described by a Breit-Wigner shape with parameters\n$m_{K^{*}}/m_{\\pi} = 3.808(18)$ and $g^{\\mathrm{BW}}_{K^{*}K\\pi} = 5.33(20)$\nwhich are insensitive to the inclusion of $d$-wave mixing and variation of the\n$s$-wave parametrization. An effective range description of the near-threshold\n$s$-wave amplitude yields $m_{\\pi}a_0 = -0.353(25)$."
    },
    {
        "anchor": "Phase structure of 3D Z(N) lattice gauge theories at finite temperature:\n  large-N and continuum limits: We study numerically three-dimensional Z(N) lattice gauge theories at finite\ntemperature, for N = 5, 6, 8, 12, 13 and 20 on lattices with temporal extension\n$N_t$ = 2, 4, 8. For each model, we locate phase transition points and\ndetermine critical indices. We propose also the scaling of critical points with\nN. The data obtained enable us to verify the scaling near the continuum limit\nfor the Z(N) models at finite temperatures.",
        "positive": "Corrections to finite-size scaling in two-dimensional O(N) sigma-models: We have considered the corrections to the finite-size-scaling functions for a\ngeneral class of $O(N)$ $\\sigma$-models with two-spin interactions in two\ndimensions for $N=\\infty$. We have computed the leading corrections finding\nthat they generically behave as $(f(z) \\log L + g(z))/L^2$ where $z = m(L) L$\nand $m(L)$ is a mass scale; $f(z)$ vanishes for Symanzik improved actions for\nwhich the inverse propagator behaves as $q^2 + O(q^6)$ for small $q$, but not\nfor on-shell improved ones. We also discuss a model with four-spin interactions\nwhich shows a much more complicated behaviour."
    },
    {
        "anchor": "Continuum Limit of the Heavy-Light Decay Constant with the Quenched\n  Wilson Quark Action: We explore the problems in calculating the decay constant for heavy-light\nmesons using the quenched Wilson quark action for both heavy and light quarks.\nWe find that the continuum limit of the decay constant is reasonably converged\namong different prescriptions after the continuum limit is taken. A number of\ntechnical problems associated with prescriptions are also addressed.",
        "positive": "Isospin-breaking corrections to the muon magnetic anomaly in Lattice QCD: In this contribution we present a lattice calculation of the leading-order\nelectromagnetic and strong isospin-breaking (IB) corrections to the\nquark-connected hadronic-vacuum-polarization (HVP) contribution to the\nanomalous magnetic moment of the muon. The results are obtained adopting the\nRM123 approach in the quenched-QED approximation and using the QCD gauge\nconfigurations generated by the ETM Collaboration with $N_f = 2+1+1$ dynamical\nquarks, at three values of the lattice spacing ($a \\simeq 0.062, 0.082, 0.089$\nfm), at several lattice volumes and with pion masses between $\\simeq 210$ and\n$\\simeq 450$ MeV. After the extrapolations to the physical pion mass and to the\ncontinuum and infinite-volume limits the contributions of the light, strange\nand charm quarks are respectively equal to $\\delta a_\\mu^{\\rm HVP}(ud) = 7.1 ~\n(2.5) \\cdot 10^{-10}$, $\\delta a_\\mu^{\\rm HVP}(s) = -0.0053 ~ (33) \\cdot\n10^{-10}$ and $\\delta a_\\mu^{\\rm HVP}(c) = 0.0182 ~ (36) \\cdot 10^{-10}$. At\nleading order in $\\alpha_{em}$ and $(m_d - m_u) / \\Lambda_{QCD}$ we obtain\n$\\delta a_\\mu^{\\rm HVP}(udsc) = 7.1 ~ (2.9) \\cdot 10^{-10}$, which is currently\nthe most accurate determination of the IB corrections to $a_\\mu^{\\rm HVP}$."
    },
    {
        "anchor": "Theoretical foundation for the Index Theorem on the lattice with\n  staggered fermions: A way to identify the would-be zero-modes of staggered lattice fermions away\nfrom the continuum limit is presented. Our approach also identifies the\nchiralities of these modes, and their index is seen to be determined by gauge\nfield topology in accordance with the Index Theorem. The key idea is to\nconsider the spectral flow of a certain hermitian version of the staggered\nDirac operator. The staggered fermion index thus obtained can be used as a new\nway to assign the topological charge of lattice gauge fields. In a numerical\nstudy in U(1) backgrounds in 2 dimensions it is found to perform as well as the\nWilson index while being computationally more efficient. It can also be\nexpressed as the index of an overlap Dirac operator with a new staggered\nfermion kernel.",
        "positive": "The Lattice Calculation of Moments of Structure Functions: Some aspects of recent QCDSF-UKQCD nucleon moments of structure function\ncomputations (both quenched and unquenched) are reviewed in an effort to\nexplore the light quark mass regime, lattice spacing effects and quenching\nartefacts."
    },
    {
        "anchor": "Searching for the QCD critical point using Lee-Yang edge singularities: Using $N_f=2+1$ QCD calculations at physical quark mass and purely imaginary\nbaryon chemical potential, we locate Lee-Yang edge singularities in the complex\nchemical potential plane. These singularities have been obtained by the\nmulti-point Pad\\'e approach applied to the net baryon number density. We\nrecently showed that singularities extracted with this approach are consistent\nwith universal scaling near the Roberge-Weiss transition. Here we study the\nuniversal scaling of these singularities in the vicinity of the QCD critical\nendpoint. Making use of an appropriate scaling ansatz, we extrapolate these\nsingularities on $N_\\tau=6$ and $N_\\tau=8$ lattices towards the real axis to\nestimate the position of a possible QCD critical point. We find an approach\ntoward the real axis with decreasing temperature. We compare this estimate with\na HotQCD estimate obtained from poles of a [4,4]-Pad\\'e resummation of the\neighth-order Taylor expansion of the QCD pressure.",
        "positive": "The QCD phase diagram for small chemical potentials: We compute derivatives of thermodynamic quantities with respect to $\\mu$, at\n$\\mu=0$ for 2 and 3 flavors of degenerate quark masses. This allows us to\nestimate the phase transition line in the $T,\\mu$ plane and quantify the\ninfluence of a non vanishing chemical potential on the equation of state by\ncomputing lines of constant energy, pressure and density. Moreover we evaluate\nthe order of the QCD phase transition by measuring the Binder Cumulant of the\nchiral condensate. This gives access to the chiral critical point on the phase\ntransition line."
    },
    {
        "anchor": "Comment on \"On the Origin of the OZI Rule in QCD\", by N. Isgur and H. B.\n  Thacker: We comment on the recent paper (hep-lat/0005006) by Isgur and Thacker on the\norigin of the OZI rule in QCD. We show that instantons explain the sign and\nmagnitude of the observed OZI-violating amplitude in all mesonic channels, not\njust in the $\\eta'$ channel. We comment on the role of instantons in hadronic\nspectroscopy and the relation between instantons and the large $N_c$ limit of\nQCD.",
        "positive": "An Overview of Lattice Results for Parton Distribution Functions: Following a ground-breaking proposal by Ji~\\cite{PhysRevLett.110.262002},\nnumerical simulations of Quantum Chromo Dynamics (QCD) on a Euclidean lattice\nhave provided new, valuable information on the structure of hadrons. In this\ntalk, we briefly review the lattice approach to the reconstruction of parton\ndensities, highlighting the connection between lattice observables and parton\ndensities, with a focus on theoretical issues. Since parton distributions are\nextracted from lattice data by solving an inverse problem, we discuss some of\nthe difficulties that affect these determinations and how they can be\nformulated in a Bayesian framework."
    },
    {
        "anchor": "Two-point functions of quenched lattice QCD in Numerical Stochastic\n  Perturbation Theory. (II) The gluon propagator in Landau gauge: This is the second of two papers devoted to the perturbative computation of\nthe ghost and gluon propagators in SU(3) Lattice Gauge Theory. Such a\ncomputation should enable a comparison with results from lattice simulations in\norder to reveal the genuinely non-perturbative content of the latter. The gluon\npropagator is computed by means of Numerical Stochastic Perturbation Theory:\nresults range from two up to four loops, depending on the different lattice\nsizes. The non-logarithmic constants for one, two and three loops are\nextrapolated to the lattice spacing $a \\to 0$ continuum and infinite volume $V\n\\to \\infty$ limits.",
        "positive": "Two-loop renormalization of fermion bilinear operators on the lattice: We compute the renormalization functions on the lattice, in the RI' scheme,\nof local bilinear quark operators $\\bar{\\psi}\\Gamma\\psi$, where $\\Gamma= 1,\n\\gamma_5, \\gamma_\\mu, \\gamma_5\\gamma_\\mu, \\gamma_5\\sigma_{\\mu\\nu}$. This\ncalculation is carried out to two loops for the first time. We consider both\nthe flavor non-singlet and singlet operators.\n  As a prerequisite for the above, we compute the quark field renormalization,\n$Z_\\psi$, up to two loops. We also compute the 1-loop renormalization functions\nfor the gluon field, $Z_A$, ghost field, $Z_c$, gauge parameter, $Z_\\alpha$,\nand coupling constant $Z_g$.\n  We use the clover action for fermions and the Wilson action for gluons. Our\nresults are given as an explicit function of the coupling constant, the clover\ncoefficient $c_{SW}$, and the number of fermion colors ($N_c$) and flavors\n($N_f$), in the renormalized Feynman gauge. All 1-loop quantities are evaluated\nin an arbitrary gauge.\n  Finally, we present our results in the MS-bar scheme, for easier comparison\nwith calculations in the continuum. We have generalized to fermionic fields in\nan arbitrary representation. Some special features of superficially divergent\nintegrals, obtained from the evaluation of two-loop Feynman diagrams, are\npresented in detail in Ref. 1."
    },
    {
        "anchor": "Heavy dense QCD and nuclear matter from an effective lattice theory: A three-dimensional effective lattice theory of Polyakov loops is derived\nfrom QCD by expansions in the fundamental character of the gauge action, u, and\nthe hopping parameter, \\kappa, whose action is correct to \\kappa^n u^m with\nn+m=4. At finite baryon density, the effective theory has a sign problem which\nmeets all criteria to be simulated by complex Langevin as well as by Monte\nCarlo on small volumes. The theory is valid for the thermodynamics of heavy\nquarks, where its predictions agree with simulations of full QCD at zero and\nimaginary chemical potential. In its region of convergence, it is moreover\namenable to perturbative calculations in the small effective couplings. In this\nwork we study the challenging cold and dense regime. We find unambiguous\nevidence for the nuclear liquid gas transition once the baryon chemical\npotential approaches the baryon mass, and calculate the nuclear equation of\nstate. In particular, we find a negative binding energy per nucleon causing the\ncondensation, whose absolute value decreases exponentially as mesons get\nheavier. For decreasing meson mass, we observe a first order liquid gas\ntransition with an endpoint at some finite temperature, as well as gap between\nthe onset of isospin and baryon condensation.",
        "positive": "Center-symmetric dimensional reduction of hot Yang-Mills theory: It is expected that incorporating the center symmetry in the conventional\ndimensionally reduced effective theory for high-temperature SU(N) Yang-Mills\ntheory, EQCD, will considerably extend its applicability towards the\ndeconfinement transition. The construction of such a center-symmetric effective\ntheory for the case of two colors is reviewed and lattice simulation results\nare presented. The simulations demonstrate that unlike EQCD, the new\ncenter-symmetric theory undergoes a second order confining phase transition in\ncomplete analogy with the full theory."
    },
    {
        "anchor": "Lattice cutoff effects for F_Ds with improved Wilson fermions - a final\n  lesson from the quenched case: In view of the recent excitement about a tension between determinations of\nf_Ds from experiment and from simulations of lattice QCD with dynamical quarks,\nwe try to clear up the picture of lattice determinations in the continuum limit\nof the quenched approximation. For O(a) improved Wilson quarks we see linear\nscaling in the squared lattice spacing a^2 only for a<~0.08fm. For coarser\nlattices we observe significant contaminations from higher order cutoff\neffects. As an aside we also study the scaling of the charm quark mass and the\nratio of the vector to the pseudo-scalar decay constant and the spin-splitting.",
        "positive": "Meson spectrum in SU(N) gauge theories with quarks in higher\n  representations: A check of Casimir scaling hypothesis: Gauge theories with gauge group $SU(N)$ and quarks belonging to arbitrary\nrepresentations of $SU(N)$ form a rich landscape of QCD-like theories, whose\nstudy can shed new light on the properties of confinement. Four cases are\nparticularly worth of interest: quarks in the fundamental representation,\nquarks in the 2-indice (anti)symmetric representation and quarks in the adjoint\nrepresentation. The last three corresponding QCD-like theories are equivalent\nat large-$N$ for bosonic observables: It is the orientifold equivalence. The\nbehavior of the lightest vector meson mass versus $N$ has been studied in\nquenched lattice QCD in the chiral limit in these theories. We show that the\nobserved behaviors are compatible with a string tension proportional to the\nquadratic Casimir of $SU(N)$ in the quark color representation, $\\textit{i.e.}$\nwith the Casimir scaling hypothesis. The large-$N$ limit of some excited meson\nmasses computed in quenched lattice QCD with quarks in the fundamental\nrepresentation is also shown to be compatible with QCD string's well-known\nsignature: Regge trajectories."
    },
    {
        "anchor": "Schwinger Model with the Overlap-Dirac Operator: exact results versus a\n  physics motivated approximation: We propose new techniques for the numerical implementation of the\noverlap-Dirac operator, which exploit the physical properties of the underlying\ntheory to avoid nested algorithms. We test these procedures in the\ntwo-dimensional Schwinger model and the results are very promising. These\ntechniques can be directly applied to QCD simulations. We also present a\ndetailed computation of the spectrum and the chiral properties of the Schwinger\nmodel in the overlap lattice formulation.",
        "positive": "Spin correlations and velocity-scaling in color-octet NRQCD matrix\n  elements: We compute spin-dependent decay matrix elements for S-wave charmonium and\nbottomonium in lattice nonrelativistic quantum chromodynamics (NRQCD).\nParticular emphasis is placed upon the color-octet matrix elements, since the\ncorresponding production matrix elements are expected to appear in the dominant\ncontributions to the production cross sections at large transverse momenta. We\nuse three slightly different versions of the heavy-quark lattice Green's\nfunctions in order to minimize the contributions that scale as powers of the\nultraviolet cutoff. The lattice matrix elements that we calculate obey the\nhierarchy that is suggested by the velocity-scaling rules of NRQCD."
    },
    {
        "anchor": "Dihedral Lattice Gauge Theories on a Quantum Annealer: We study lattice gauge theory with discrete, non-Abelian gauge groups. We\nextend the formalism of previous studies on D-Wave's quantum annealer as a\ncomputing platform to finite, simply reducible gauge groups. As an example, we\nuse the dihedral group $D_n$ with $n=3,4$ on a two plaquette ladder for which\nwe provide proof-of-principle calculations of the ground-state and employ the\nknown time evolution formalism with Feynman clock states.",
        "positive": "Non-perturbative renormalization of the static quark theory in a large\n  volume: We report on progress to renormalize non-pertubatively the static heavy quark\ntheory on the lattice. In particular, we present first results for\nposition-space renormalization scheme for heavy-light bilinears. We test our\napproach on RBC's 16^3 x 32 lattice ensemble with m_pi = 420 MeV, Iwasaki gauge\naction and domain wall light fermions."
    },
    {
        "anchor": "Simple check of the vacuum structure in full QCD lattice simulations: Given the increasing availability of lattice data for (unquenched) QCD with\n$N_f=2$, it is worth while to check whether the generated vacuum significantly\ndeviates from the quenched one. I discuss a specific attempt to do this on the\nbasis of topological susceptibility data gained at various sea-quark masses,\nsince for this observable detailed predictions are available. The upshot is\nthat either discretization effects in dynamical simulations are still\nuntolerably large or the vacuum structure in 2-flavour QCD substantially\ndeviates from that in the theory with 3 (or 2+1) light quarks.",
        "positive": "N to Delta electromagnetic and axial form factors in full QCD: Lattice results on the N to Delta electromagnetic, axial-vector and\npseudoscalar form factors are evaluated using dynamical staggered sea quarks\nand domain wall valence quarks for pion masses in the range of 580-350 MeV, as\nwell as, dynamical and quenched Wilson fermions for similar pion masses."
    },
    {
        "anchor": "More on volume dependence of spectral weight function: Spectral weight functions are easily obtained from two-point correlation\nfunctions and they might be used to distinguish single-particle from\nmulti-particle states in a finite-volume lattice calculation, a problem crucial\nfor many lattice QCD simulations. In previous studies, it is shown that the\nspectral weight function for a broad resonance shares the typical volume\ndependence of a two-particle scattering state i.e. proportional to $1/L^3$ in a\nlarge cubic box of size $L$ while the narrow resonance case requires further\ninvestigation. In this paper, a generalized formula is found for the spectral\nweight function which incorporates both narrow and broad resonance cases.\nWithin L\\\"uscher's formalism, it is shown that the volume dependence of the\nspectral weight function exhibits a single-particle behavior for a extremely\nnarrow resonance and a two-particle behavior for a broad resonance. The\ncorresponding formulas for both $A^+_1$ and $T^-_1$ channels are derived. The\npotential application of these formulas in the extraction of resonance\nparameters are also discussed.",
        "positive": "Mass of the b-quark and B-decay constants from Nf=2+1+1 twisted-mass\n  Lattice QCD: We present precise lattice computations for the b-quark mass, the quark mass\nratios mb/mc and mb/ms as well as the leptonic B-decay constants. We employ\ngauge configurations with four dynamical quark flavors, up/down, strange and\ncharm, at three values of the lattice spacing (a ~ 0.06 - 0.09 fm) and for pion\nmasses as low as 210 MeV. Interpolation in the heavy quark mass to the bottom\nquark point is performed using ratios of physical quantities computed at nearby\nquark masses exploiting the fact that these ratios are exactly known in the\nstatic quark mass limit. Our results are also extrapolated to the physical pion\nmass and to the continuum limit and read: mb(MSbar, mb) = 4.26(10) GeV, mb/mc =\n4.42(8), mb/ms = 51.4(1.4), fBs = 229(5) MeV, fB = 193(6) MeV, fBs/fB =\n1.184(25) and (fBs/fB)/(fK/fpi) = 0.997(17)."
    },
    {
        "anchor": "From the Abelian projected flux tube to the dual Abelian Higgs model: A recent detailed study of the Q-anti-Q flux tube and its DAHM analysis is\nreported.",
        "positive": "Traces of a fixed point: Unravelling the phase diagram at large Nf: With a sufficiently high number of fundamental fermionic flavours present,\nYang-Mills theory develops an infrared fixed point and becomes\n(quasi-)conformal in nature. The range of flavour numbers for which this occurs\ndefines the conformal window, the lower limit of which has yet to be\ndetermined. We studied the phase diagram of SU(3) Yang-Mills theory with twelve\nflavours of staggered fermions. Here we present evidence for the occurrence of\na bulk transition towards a chirally broken phase and the existence of a\nCoulomb phase on the symmetric side of this transition, using results from the\nmeasurements of the chiral condensate and spectrum, leading to the\ndetermination of a positive sign of the beta function. Assuming the validity of\nthe Appelquist-Miransky-Yamawaki scenario, this implies the existence of a\nconformal window that comprises the theory under investigation."
    },
    {
        "anchor": "Charm physics with Moebius Domain Wall Fermions: We present results showing that Domain Wall fermions are a suitable\ndiscretisation for the simulation of heavy quarks. This is done by a continuum\nscaling study of charm quarks in a M\\\"obius Domain Wall formalism using a\nquenched set-up. We find that discretisation effects remain well controlled by\nthe choice of Domain Wall parameters preparing the ground work for the ongoing\ndynamical $2+1f$ charm program of RBC/UKQCD.",
        "positive": "An Exploratory Lattice Study of Spectator Effects in Inclusive Decays of\n  the Lambda_b Baryon: A possible explanation of the apparent disrepency between the theoretical\nprediction and experimental measurement of the ratio of lifetimes\n$\\tau(\\Lambda_b)/\\tau(B_d)$ is that ``spectator effects'', which appear at\n$O(1/m_b^3)$ in the heavy quark expansion, contribute significantly. We\ninvestigate this possibility by computing the corresponding operator matrix\nelements in a lattice simulation. We find that spectator effects are indeed\nsignificant, but do not appear to be sufficiently large to account for the full\ndiscrepency. We stress, however, that this is an exploratory study, and it is\nimportant to check our conclusions on a larger lattice and using a larger\nsample of gluon configurations."
    },
    {
        "anchor": "Gauge fixing, zero--momentum modes and the calculation of masses on a\n  lattice: It is shown that the zero--momentum modes can strongly affect the values of\nthe masses, for example the magnetic screening mass $m_m$, calculated from\ngauge--dependent correlators with zero momentum.",
        "positive": "A first study of epsilon'/epsilon on the lattice using domain wall\n  fermions: This paper has been withdrawn."
    },
    {
        "anchor": "Exploring walking behavior in SU(3) gauge theory with 4 and 8 HISQ\n  quarks: We present the report of the LatKMI collaboration on the lattice QCD\nsimulation for the cases of 4 and 8 flavors. The Nf=8 in particular is\ninteresting from the model-building point of view: The typical walking\ntechnicolor model with the large anomalous dimension is the so-called\none-family model (Farhi-Susskind model). Thus we explore the walking behavior\nin LQCD with 8 HISQ quarks by comparing with the 4-flavor case (in which the\nchiral symmetry is spontaneously broken). We report preliminary results on the\nspectrum, analyzed through the chiral perturbation theory and the finite-size\nhyperscaling, and we discuss the availability of the Nf=8 QCD to the\nphenomenology.",
        "positive": "One-Loop Diagrams in Lattice QCD with Wilson Fermions: A comprehensive number of integrals emerging in one-loop computations in a\ngauge perturbation theory on the lattice with Wilson fermions at $r=1$ is\ncomputed using the Burgio--Caracciolo--Pelissetto algorithm and the FORM\npackage. An explicit analytical form of the recursion relations needed for such\ncomputations is presented."
    },
    {
        "anchor": "Ultralocality on the lattice: It is shown that the nonlocal Dirac operator yielded by a lattice model that\npreserves chiral symmetry and uniqueness of fields, approaches to an ultralocal\nand invariant under translations operator when the size of the lattice tends to\nzero.",
        "positive": "Charged fermion states in the quenched U(1) chiral Wilson-Yukawa model: Property of charged fermion states is investigated in the quenched U(1)\nchiral Wilson-Yukawa model. Fitting the charged fermion propagator with a\nsingle hyperbolic cosine does not yield reliable results. On the other hand the\nbehavior of the propagator including large lattice size dependence is well\ndescribed by the large Wilson-Yukawa coupling expansion, providing strong\nevidence that no charged fermion state exists as an asymptotic particle in this\nmodel."
    },
    {
        "anchor": "Baryonic Screening Masses in High Temperature QCD: We compute the screening masses of fields with nucleon quantum numbers for a\nwide range of temperatures between $T \\sim 1$ GeV and $T\\sim 160$ GeV. The\ncomputation has been performed by means of Monte Carlo simulations of lattice\nQCD with $N_f=3$ flavors of $O(a)$-improved Wilson fermions: we exploit a novel\nstrategy which has recently allowed to determine for the first time non-singlet\nmesonic screening masses up to extremely high temperatures. The baryonic\nscreening masses are measured with a few per-mille precision in the continuum\nlimit, and percent deviations from the free theory result $3\\pi T$ are clearly\nvisible even at the highest temperatures. The observed degeneracy of the\npositive and negative parity state's screening mass, expected from Ward\nidentities associated to non-singlet axial transformations, provides further\nevidence for the restoration of chiral symmetry in the high temperature regime\nof QCD.",
        "positive": "On the Statistics of Baryon Correlation Functions in Lattice QCD: A systematic analysis of the structure of single-baryon correlation functions\ncalculated with lattice QCD is performed, with a particular focus on\ncharacterizing the structure of the noise associated with quantum fluctuations.\nThe signal-to-noise problem in these correlation functions is shown, as long\nsuspected, to result from a sign problem. The log-magnitude and complex phase\nare found to be approximately described by normal and wrapped normal\ndistributions respectively. Properties of circular statistics are used to\nunderstand the emergence of a large time noise region where standard energy\nmeasurements are unreliable. Power-law tails in the distribution of baryon\ncorrelation functions, associated with stable distributions and \"Levy flights\",\nare found to play a central role in their time evolution. A new method of\nanalyzing correlation functions is considered for which the signal-to-noise\nratio of energy measurements is constant, rather than exponentially degrading,\nwith increasing source-sink separation time. This new method includes an\nadditional systematic uncertainty that can be removed by performing an\nextrapolation, and the signal-to-noise problem re-emerges in the statistics of\nthis extrapolation. It is demonstrated that this new method allows accurate\nresults for the nucleon mass to be extracted from the large-time noise region\ninaccessible to standard methods. The observations presented here are expected\nto apply to quantum Monte Carlo calculations more generally. Similar methods to\nthose introduced here may lead to practical improvements in analysis of noisier\nsystems."
    },
    {
        "anchor": "QCD on Coarse Lattices: We show that the perturbatively-improved gluon action for QCD, once it is\ntadpole-improved, gives accurate results even with lattice spacings as large as\n0.4~fm. {\\em No\\/} tuning of the couplings is required. Using this action and\nlattice spacing, we obtain a static potential that is rotationally invariant to\nwithin a few percent, the spin-averaged charmonium spectrum accurate to within\n30--40~MeV, and scaling to within 5--10\\%. We demonstrate that simulations on\ncoarse lattices are several orders of magnitude less costly than simulations\nusing current methods.",
        "positive": "Anomalous gauge theories revisited: A possible formulation of chiral gauge theories with an anomalous fermion\ncontent is re-examined in light of the lattice framework based on the\nGinsparg-Wilson relation. It is shown that the fermion sector of a wide class\nof anomalous non-abelian theories cannot consistently be formulated within this\nlattice framework. In particular, in 4 dimension, {\\it all} anomalous\nnon-abelian theories are included in this class. Anomalous abelian chiral gauge\ntheories cannot be formulated with compact $\\U(1)$ link variables, while a\nnon-compact formulation is possible at least for the vacuum sector in the space\nof lattice gauge fields. Our conclusion is not applied to effective low-energy\ntheories with an anomalous fermion content which are obtained from an\nunderlying anomaly-free theory by sending the mass of some of fermions to\ninfinity. For theories with an anomalous fermion content in which the anomaly\nis cancelled by the Green-Schwarz mechanism, a possibility of a consistent\nlattice formulation is not clear."
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory in the Schr\u00f6dinger Functional: The Schr\\\"odinger functional (SF) is a powerful and widely used tool for the\ntreatment of a variety of problems in renormalization and related areas. Albeit\noffering many conceptual advantages, one major downside of the SF scheme is the\nfact that perturbative calculations quickly become cumbersome with the\ninclusion of higher orders in the gauge coupling and hence the use of an\nautomated perturbation theory framework is desirable. We present the\nimplementation of the SF in numerical stochastic perturbation theory (NSPT) and\ncompare first results for the running coupling at two loops in pure SU(3)\nYang-Mills theory with the literature.",
        "positive": "The QCD Chiral Condensate from the Lattice: We determine the chiral condensate from simulations of quenched lattice QCD\nwith Wilson fermions. Our measurements have been obtained with high statistics\nat three values of the gauge coupling, corresponding to UV cutoffs in the range\n2 - 4 GeV. Several improvements have been made with respect to earlier lattice\ncomputations. The most important are the non-perturbative renormalization of\nthe condensate, the use of the tree-level improved Clover action and the\nreduction of the systematic error due to uncertainties in the lattice\ncalibration. Our result for the chiral condensate in the $\\msbar$ scheme is\n  (\\bar\\psi \\psi)^{\\msbar}(mu = 2 GeV)\n  = - 0.0147(8)(16)(12) GeV^3\n  = - [245(4)(9)(7) MeV]^3\n  where the first error is statistical, the second is due to the\nnon-perturbative renormalization and the third due to the lattice calibration."
    },
    {
        "anchor": "Lattice Calculation of the $K_L$-$K_S$ mass difference: We report progress on calculating the $K_L$-$K_S$ mass difference in lattice\nQCD. T he calculation is performed on a 2+1 flavor, domain wall fermion,\n$16^3\\times 32$ en semble with a 421 MeV pion mass. We include only\ncurrent-current operators and drop all disconnected and double penguin diagrams\nin the calculation. The calculation is made finite through the GIM mechanism by\nintroducing a valence charm quark. The long distance effects are discussed\nseparately for each of the two parity channels. Whil e we find a clear long\ndistance contribution from the parity odd channel, the signal to noise ratio in\nthe parity even channel is exponentially decreasing and the two-p ion state can\nbe seen in only a subclass of amplitudes. We obtain the mass differenc e\n$\\Delta M_K$ in a range from $5.12(24)\\times 10^{-12}$ to $9.31(66) \\times\n10^{-12}$ MeV for kaon masses between 563 and 839 MeV.",
        "positive": "Control variates for lattice field theory: In most lattice field theories, correlators are plagued by a signal-to-noise\nproblem of exponential difficulty in the time separation. We propose a method\nfor improving the signal-to-noise ratio, in which control variates are\nsystematically constructed from lattice Schwinger-Dyson relations. The method\nis demonstrated on various two-dimensional lattices in scalar field theory, and\na strategy for scaling to larger systems is explored."
    },
    {
        "anchor": "$\\bar{b}\\bar{c}\\,q_1q_2$four-quark states from Lattice QCD: We present the results of a lattice calculation of four-quark states with the\nquark contents $\\bar{b}\\bar{c}q_1q_2$ where $q_1,q_2 \\in u,d,s$. For the spin 1\nstates, when the light quark ($q_1, q_2$) masses are lighter, we find at least\none energy level below the possible elastic threshold energy levels. These\ncalculations are performed on three dynamical $N_f = 2+1+1$ highly improved\nstaggered quark ensembles at lattice spacings of about 0.12, 0.09, and 0.06 fm.\nWe use the overlap action for light to charm quarks while a non-relativistic\naction with non-perturbatively improved coefficients is employed for the bottom\nquark.",
        "positive": "Dynamical Scaling from Multi-Scale Measurements: We present a new measure of the Dynamical Critical behavior: the \"Multi-scale\nDynamical Exponent (MDE)\""
    },
    {
        "anchor": "The Quenched Approximation in Health and in Sickness: We present results for physical quantities computed in quenched chiral\nperturbation theory and compare them with the corresponding unquenched\nexpressions. We also point out an apparent theoretical problem of the quenched\napproximation. latex, file espcrc2.sty needed (appended at the end: search for\nespcrc2.sty).",
        "positive": "Introducing Dynamical Triangulations to the Type IIB Superstrings: In order to consider non-perturbative effects of superstrings, we try to\napply dynamical triangulations to the type IIB superstrings. The discretized\naction is constructed from the type IIB matrix model proposed as a constructive\ndefinition of superstring theory. The action has the local N=2 supersymmetry\nexplicitly, and has no extra fermionic degrees of freedom. We evaluate the\npartition function for some simple configurations and discuss constraints\nrequired from the finiteness of partition functions."
    },
    {
        "anchor": "Quark masses using twisted mass fermion gauge ensembles: We present a calculation of the up, down, strange and charm quark masses\nperformed within the lattice QCD framework. We use the twisted mass fermion\naction and carry out simulations that include in the sea two light\nmass-degenerate quarks, as well as the strange and charm quarks. In the\nanalysis we use gauge ensembles simulated at three values of the lattice\nspacing and with light quarks that correspond to pion masses in the range from\n350 MeV to the physical value, while the strange and charm quark masses are\ntuned approximately to their physical values. We use several quantities to set\nthe scale in order to check for finite lattice spacing effects and in the\ncontinuum limit we get compatible results. The quark mass renormalization is\ncarried out non-perturbatively using the RI'-MOM method converted into the\n$\\overline{\\rm MS}$ scheme. For the determination of the quark masses we use\nphysical observables from both the meson and the baryon sectors, obtaining\n$m_{ud} = 3.636(66)(^{+60}_{-57})$~MeV and $m_s =\n98.7(2.4)(^{+4.0}_{-3.2})$~MeV in the $\\overline{\\rm MS}(2\\,{\\rm GeV})$ scheme\nand $m_c = 1036(17)(^{+15}_{-8})$~MeV in the $\\overline{\\rm MS}(3\\,{\\rm GeV})$\nscheme, where the first errors are statistical and the second ones are\ncombinations of systematic errors. For the quark mass ratios we get $m_s /\nm_{ud} = 27.17(32)(^{+56}_{-38})$ and $m_c / m_s = 11.48(12)(^{+25}_{-19})$.",
        "positive": "Microcanonical Simulation of Complex Actions: The Wess Zumino Witten\n  Case: We present the main results of our microcanonical simulation of the Wess\nZumino Witten action functional. This action, being highly non-trivial and\ncapable of exhibiting many different phase transitions, is chosen to be\nrepresentative of general complex actions. We verify the applicability of\nmicrocanonical simulation by successfully obtaining two of the many critical\npoints of the Wess Zumino Witten action. The microcanonical algorithm has the\nadditional advantage of exhibiting critical behaviour for a small $8\\times 8$\nlattice. We also briefly discuss the subtleties that, in general, arise in\nsimulating a complex action. Our algorithm for complex actions can be extended\nto the study of\n  D-branes in the Wess Zumino Witten action."
    },
    {
        "anchor": "A Lattice Study of the Gluon Propagator in Momentum Space: We consider pure glue QCD at beta=5.7, beta=6.0 and beta=6.3. We evaluate the\ngluon propagator both in time at zero 3-momentum and in momentum space. From\nthe former quantity we obtain evidence for a dynamically generated effective\nmass, which at beta=6.0 and beta=6.3 increases with the time separation of the\nsources, in agreement with earlier results. The momentum space propagator G(k)\nprovides further evidence for mass generation. In particular, at beta=6.0, for\nk less than 1 GeV, the propagator G(k) can be fit to a continuum formula\nproposed by Gribov and others, which contains a mass scale b, presumably\nrelated to the hadronization mass scale. For higher momenta Gribov's model no\nlonger provides a good fit, as G(k) tends rather to follow an inverse power\nlaw. The results at beta=6.3 are consistent with those at beta=6.0, but only\nthe high momentum region is accessible on this lattice. We find b in the range\nof three to four hundred MeV and the exponent of the inverse power law about\n2.7. On the other hand, at beta=5.7 (where we can only study momenta up to 1\nGeV) G(k) is best fit to a simple massive boson propagator with mass m. We\nargue that such a discrepancy may be related to a lack of scaling for low\nmomenta at beta=5.7. {}From our results, the study of correlation functions in\nmomentum space looks promising, especially because the data points in Fourier\nspace turn out to be much less correlated than in real space.",
        "positive": "Non-Perturbative Renormalization Group Flows in Two-Dimensional Quantum\n  Gravity: Recently a block spin renormalization group approach was proposed for the\ndynamical triangulation formulation of two-dimensional quantum gravity. We use\nthis approach to examine non-perturbatively a particular class of higher\nderivative actions for pure gravity."
    },
    {
        "anchor": "The Coulomb law in the pure gauge U(1) theory on a lattice: We study the heavy charge potential in the Coulomb phase of pure gauge\ncompact U(1) theory on the lattice. We calculate the static potential\n$V_W(T,{\\vec R})$ from Wilson loops on a $16^3 \\times 32$ lattice and compare\nwith the predictions of lattice perturbation theory. We investigate finite size\neffects and, in particular, the importance of non-Coulomb contributions to the\npotential. We also comment on the existence of a maximal coupling in the\nCoulomb phase of pure gauge U(1) theory.",
        "positive": "Determining the strange quark mass for 2-flavour QCD: Using the O(a) Symanzik improved action an estimate is given for the strange\nquark mass for unquenched (n_f=2) QCD. The determination is via the axial Ward\nidentity (AWI) and includes a non-perturbative evaluation of the\nrenormalisation constant. Numerical results have been obtained at several\nlattice spacings, enabling the continuum limit to be taken. Our results\nindicate a value for the strange quark mass (in the MS-bar scheme at a scale of\n2 GeV) in the range 100 - 130 MeV. A comparison is also made with other recent\nlattice determinations of the strange quark mass using dynamical sea quarks."
    },
    {
        "anchor": "Stochastic calculation of the QCD Dirac operator spectrum with Mobius\n  domain-wall fermion: We calculate the spectral function of the QCD Dirac operator using the\nfour-dimensional effective operator constructed from the Mobius domain-wall\nimplementation. We utilize the eigenvalue filtering technique combined with the\nstochastic estimate of the mode number. The spectrum in the entire eigenvalue\nrange is obtained with a single set of measurements. Results on 2+1-flavor\nensembles with Mobius domain-wall sea quarks at lattice spacing ~ 0.08 fm are\nshown.",
        "positive": "A construction of the Glashow-Weinberg-Salam model on the lattice with\n  exact gauge invariance: We present a gauge-invariant and non-perturbative construction of the\nGlashow-Weinberg-Salam model on the lattice, based on the lattice Dirac\noperator satisfying the Ginsparg-Wilson relation. Our construction covers all\nSU(2) topological sectors with vanishing U(1) magnetic flux and would be usable\nfor a description of the baryon number non-conservation. In infinite volume, it\nprovides a gauge-invariant regularization of the electroweak theory to all\norders of perturbation theory. First we formulate the reconstruction theorem\nwhich asserts that if there exists a set of local currents satisfying cetain\nproperties, it is possible to reconstruct the fermion measure which depends\nsmoothly on the gauge fields and fulfills the fundamental requirements such as\nlocality, gauge-invariance and lattice symmetries. Then we give a closed\nformula of the local currents required for the reconstruction theorem."
    },
    {
        "anchor": "The Positive-Parity Baryon Spectrum and the Role of Hybrid Baryons: We calculate the low-lying spectra for the positive-parity $\\Delta$ and $N$\nat two pion masses of 358 and 278 MeV using an isotropic clover action with two\ndegenerate light-quaark and one strange-quark flavors through the application\nof the generalized variational method within the distillation framework. The\nspectrum exhibits the general features observed in previous calculations using\nan anisotropic clover lattice, with a counting of states at least as rich as\nthe quark model. Furthermore, we identify states that are hybrid in nature,\nwhere gluonic degrees of freedom play a structural role, indicatinng that such\nstates appear a feature of the excited baryon spectrum, irrespective of the\nlattice action, or the precise details of the smearing of the lattice\ninterpolating operators used to identify such states.",
        "positive": "Chiral Polarization Scale at Finite Temperature: We study the chiral polarization properties of low-lying Dirac eigenmodes at\nfinite temperature using the overlap operator. Results for pure gauge theory on\nboth sides of deconfinement phase transition are presented. We find that the\npolarization scale decreases as we increase the temperature, but it remains\nnon-zero as we cross in the deconfined phase and vanishes only when $T\\approx\n1.4 T_c$. This is caused by the presence of near-zero modes which, we find, are\nchirally polarized."
    },
    {
        "anchor": "Measuring the string susceptibility in 2D simplicial quantum gravity\n  using the Regge approach: We use Monte Carlo simulations to study pure 2D Euclidean quantum gravity\nwith $R^2$-interaction on spherical topologies, employing Regge's formulation.\nWe attempt to measure the string susceptibility exponent $\\gamma_{\\rm str}$ by\nusing a finite-size scaling Ansatz in the expectation value of $R^2$, as has\nbeen done in a previous study by Bock and Vink ( hep-lat/9406018 ). By\nconsiderably extending the range and statistics of their study we find that\nthis Ansatz is plagued by large systematic errors. The $R^2$ specific string\nsusceptibility exponent $\\GS'$ is found to agree with theoretical predictions,\nbut its determination also is subject to large systematic errors and the\npresence of finite-size scaling corrections. To circumvent this obstacle we\nsuggest a new scaling Ansatz which in principle should be able to predict both,\n$\\GS$ and $\\GS'$. First results indicate that this requires large system sizes\nto reduce the uncertainties in the finite-size scaling Ans\\\"atze. Nevertheless,\nour investigation shows that within the achievable accuracy the numerical\nestimates are still compatible with analytic predictions, contrary to the\nrecent claim by Bock and Vink.",
        "positive": "Nucleon structure from 2+1-flavor dynamical DWF ensembles: Nucleon isovector vector- and axialvector-current form factors, the\nrenormalized isovector transversity and scalar charge, and the bare quark\nmomentum and helicity moments of isovector structure functions are reported\nwith improved statistics from two recent RBC+UKQCD 2+1-flavor dynamical\ndomain-wall fermions ensembles: Iwasaki\\(\\times\\)DSDR gauge \\(32^3\\times64\\) at\ninverse lattice spacing of 1.38 GeV and pion mass of 249 and 172 MeV."
    },
    {
        "anchor": "AI and Theoretical Particle Physics: Theoretical particle physicists continue to push the envelope in both high\nperformance computing and in managing and analyzing large data sets. For\nexample, the goals of sub-percent accuracy in predictions of quantum\nchromodynamics (QCD) using large scale simulations of lattice QCD and in\nfinding signals of rare events and new physics in exabytes of data produced by\nexperiments at the high luminosity large hadron collider (LHC) require new\ntools beyond just developments in hardware. Machine learning and artificial\nintelligence offer the promise of dramatically reducing the computational cost\nand time. This chapter reviews selected areas where AI/ML tools could have a\nmajor impact, provides an overview of the challenges, and discusses how new\nideas such as normalizing flows can speed up the generation of gauge\nconfigurations needed in lattice QCD calculations; the growth of ML in\nsurrogate models and pattern matching to reduce the cost of event generators\nand in the analysis of experimental data; and in the search for viable vacua in\nthe landscape of string theories. While such approaches transform aspects of\nparticle theory into computational problems, and thus black boxes, we argue\nthat physics-aware development of these tools combined with algorithms that\nensure that the results are bias free will continue to require a deep\nunderstanding of the physics. We see this broader transformation as akin to\nformulating and extracting observables from simulations of lattice QCD, a\nnumerical integration of the path integral formulation of QCD that nevertheless\nrequires a deep understanding of the underlying quantum field theory, the\nstandard model of particle physics and effective field theory methods.",
        "positive": "The confined-deconfined interface tension, wetting, and the spectrum of\n  the transfer matrix: The reduced tension $\\sigma_{cd}$ of the interface between the confined and\nthe deconfined phase of $SU(3)$ pure gauge theory is determined from numerical\nsimulations of the first transfer matrix eigenvalues. At $T_c = 1/L_t$ we find\n$\\sigma_{cd} = 0.139(4) T_c^2$ for $L_t = 2$. The interfaces show universal\nbehavior because the deconfined-deconfined interfaces are completely wet by the\nconfined phase. The critical exponents of complete wetting follow from the\nanalytic interface solutions of a $\\Z(3)$-symmetric $\\Phi^4$ model in three\ndimensions. We find numerical evidence that the confined-deconfined interface\nis rough."
    },
    {
        "anchor": "Measurements of the Yang-Mills vacuum wavefunctional, and related\n  studies: I present numerical tests of several recent proposals for the Yang-Mills\nvacuum wavefunctional in D=2+1 dimensions. In these tests the predicted\nrelative values of the squared wavefunctional, evaluated on a finite set of\nabelian plane wave and non-abelian constant configurations, are compared to the\ncorresponding values for the true ground state, extracted from Monte Carlo\nsimulations. I also study how the 2+1 dimensional color Coulomb potential,\naveraged over a set of simple trial configurations, varies with the proximity\nof those configurations to the Gribov horizon.",
        "positive": "Pion and Kaon Distribution Amplitudes from Lattice QCD: We present the state-of-the-art lattice QCD calculation of the pion and kaon\nlight-cone distribution amplitudes (DAs) using large-momentum effective theory.\nThe calculation is done at three lattice spacings $a\\approx\\{0.06,0.09,0.12\\}$\nfm and physical pion and kaon masses, with the meson momenta $P_z =\n\\{1.29,1.72,2.15\\}$ GeV. The result is non-perturbatively renormalized in a\nrecently proposed hybrid scheme with self renormalization, and extrapolated to\nthe continuum as well as the infinite momentum limit. We find a significant\ndeviation of the pion and kaon DAs from the asymptotic form, and a large\n$SU(3)$ flavor breaking effect in the kaon DA."
    },
    {
        "anchor": "One-loop operator matching in the static heavy and domain-wall light\n  quark system with O(a) improvement: We discuss perturbative O(g^2a) matching with static heavy quarks and\ndomain-wall light quarks for lattice operators relevant to B-meson decays and\n$B^0$-$\\bar{B}^0$ mixing. The chiral symmetry of the light domain-wall quarks\ndoes not prohibit operator mixing at O(a) for these operators. The O(a)\ncorrections to physical quantities are non-negligible and must be included to\nobtain high-precision simulation results for CKM physics. We provide results\nusing plaquette, Symanzik, Iwasaki and DBW2 gluon actions and applying APE,\nHYP1 and HYP2 link-smearing for the static quark action.",
        "positive": "Quark-Antiquark Forces From SU(2) and SU(3) Gauge Theories on Large\n  Lattices: We present results on the spin-independent quark-antiquark potential in SU(3)\ngauge theory from a simulation on a 48^3*64 lattice at Beta = 6.8,\ncorresponding to a volume of (1.7 fm)^3. Moreover, a comprehensive analysis of\nspin- and velocity-dependent potentials is carried out for SU(2) gauge theory,\nwith emphasis on the short range structure, on lattices with resolutions\nranging from .02 fm to .04 fm."
    },
    {
        "anchor": "Asymptotic expansion of the lattice scalar propagator in coordinate\n  space: The asymptotic expansion of the massive scalar field propagator on a\nn-dimensional lattice is derived. The method used is based on the evaluation of\nthe asymptotic expansion of the modified Bessel function $I_{\\nu}(\\nu^{2}\n\\beta)$ as the order $\\nu$ grows to infinity.",
        "positive": "The Magnetic Structure of Light Nuclei from Lattice QCD: Lattice QCD with background magnetic fields is used to calculate the magnetic\nmoments and magnetic polarizabilities of the nucleons and of light nuclei with\n$A\\le4$, along with the cross-section for the $M1$ transition $np\\rightarrow\nd\\gamma$, at the flavor SU(3)-symmetric point where the pion mass is $m_\\pi\\sim\n806$ MeV. These magnetic properties are extracted from nucleon and nuclear\nenergies in six uniform magnetic fields of varying strengths. The magnetic\nmoments are presented in a recent Letter. For the charged states, the\nextraction of the polarizability requires careful treatment of Landau levels,\nwhich enter non-trivially in the method that is employed. The nucleon\npolarizabilities are found to be of similar magnitude to their physical values,\nwith $\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$ fm$^3$ and\n$\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$ fm$^3$, exhibiting a\nsignificant isovector component. The dineutron is bound at these heavy quark\nmasses and its magnetic polarizability, $\\beta_{nn}=1.872(+0.121/-0.113)(0.082)\n\\times 10^{-4}$ fm$^3$ differs significantly from twice that of the neutron. A\nlinear combination of deuteron scalar and tensor polarizabilities is determined\nby the energies of the $j_z=\\pm 1$ deuteron states, and is found to be\n$\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$ fm$^3$. The magnetic\npolarizabilities of the three-nucleon and four-nucleon systems are found to be\npositive and similar in size to those of the proton, $\\beta_{^{3}\\rm\nHe}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$ fm$^3$, $\\beta_{^{3}\\rm\nH}=2.6(1.7)(0.1) \\times 10^{-4}$ fm$^3$, $\\beta_{^{4}\\rm\nHe}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$ fm$^3$. Mixing between the $j_z=0$\ndeuteron state and the spin-singlet $np$ state induced by the background\nmagnetic field is used to extract the short-distance two-nucleon counterterm,\n${\\bar L}_1$, of the pionless effective theory for $NN$ systems (equivalent to\nthe meson-exchange current contribution in nuclear potential models), that\ndictates the cross-section for the $np\\to d\\gamma$ process near threshold.\nCombined with previous determinations of NN scattering parameters, this enables\nan ab initio determination of the threshold cross-section at these unphysical\nmasses."
    },
    {
        "anchor": "A review of heavy-heavy spectroscopy: Calculations of the heavy-heavy spectrum present a good opportunity for\nprecision tests of QCD using lattice techniques. All methods make use of a\nnon-relativistic expansion of the action and its systematic improvement to\nremove lattice artefacts. There was convincing demonstration this year that\nthese methods work and that the associated perturbation theory is well-behaved.\nComparison to experimental results yields an accurate value for the lattice\nspacing, a, a key result in the determination of \\alpha_{s}, and (for the first\ntime this year) the mass of the b quark (4.7(1) GeV).",
        "positive": "Spatial string tension in $N_f=2$ lattice QCD at finite temperature: The spatial string tension across a crossover from the low temperature phase\nto the high temperature phase is computed in QCD with two flavors of\nnon-perturbatively improved Wilson fermions at small lattice spacing a \\sim\n0.12fm. We find that in the low temperature phase spatial string tension agrees\nwell with zero temperature string tension. Furthermore, it does not show\nincreasing for temperatures up to T = 1.36 T_{pc}, the highest temperature\nconsidered. Our results agree with some theoretical predictions."
    },
    {
        "anchor": "Lattice QCD for Novices: This is the \"preprint\" for a paper that came out in 1998 but for some reason\nwasn't posted then.\n  Abstract:These lectures are for novices to lattice QCD. They introduce a set\nof simple ideas and numerical techniques that can be implemented in a short\nperiod of time and that are capabable of generating nontrivial, nonperturbative\nresults from lattice QCD. The simplest of these calculations can be completed\non a standard workstation or high-end personal computer.",
        "positive": "The speed of sound and specific heat in the QCD plasma: hydrodynamics,\n  fluctuations and conformal symmetry: We report the continuum limits of the speed of sound, c_s, and the specific\nheat at constant volume, c_v, in quenched QCD at temperatures of 2Tc and 3Tc.\nAt these temperatures, c_s is within 2-sigma of the ideal gas value, whereas\nc_v differs significantly from the ideal gas. However, both are compatible with\nresults expected in a theory with conformal symmetry. We investigate effective\nmeasures of conformal symmetry in the high temperature phase of QCD."
    },
    {
        "anchor": "Isgur-Wise Function on the Lattice: We review our method and numerical results for calculation of the Isgur-Wise\nfunction on the lattice. We present a discussion of the systematic errors.\nUsing recent experimental results, we find $V_{cb} = 0.044\\pm 0.005\\pm .007$.\nContribution to Lattice '93 proceedings. Needs espcrc2.sty file (included after\n\\end{document}). Search Figure1.ps for postscript files.",
        "positive": "Solving the sign problems of the massless lattice Schwinger model with a\n  dual formulation: We derive an exact representation of the massless Schwinger model on the\nlattice in terms of dual variables which are configurations of loops, dimers\nand plaquette occupation numbers. When expressed with the dual variables the\npartition sum has only real and positive terms also when a chemical potential\nor a topological term are added -- situations where the conventional\nrepresentation has a complex action problem. The dual representation allows for\nMonte Carlo simulations without restrictions on the values of the chemical\npotential or the vacuum angle."
    },
    {
        "anchor": "On the Crumpling Transition in Crystalline Random Surfaces: We investigate the crumpling transition on crystalline random surfaces with\nextrinsic curvature on lattices up to $64^2$. Our data are consistent with a\nsecond order phase transition and we find correlation length critical exponent\n$\\nu=0.89\\pm 0.07$. The specific heat exponent, $\\alpha=0.2\\pm 0.15$, is in\nmuch better agreement with hyperscaling than hitherto. The long distance\nbehaviour of tangent-tangent correlation functions confirms that the so-called\nHausdorff dimension is $d_H=\\infty$ throughout the crumpled phase.",
        "positive": "Improved interpolating fields for hadrons at non-zero momentum: We generalize Gaussian/Wuppertal smearing in order to produce non-spherical\nwave functions. We show that we can achieve a reduction in the noise-to-signal\nratio for correlation functions of certain hadrons at non-zero momentum, while\nat the same time preserving a good projection on the ground state."
    },
    {
        "anchor": "Large-q expansion of the energy cumulants for the two-dimensional\n  q-state Potts model: We have calculated the large-q expansion for the energy cumulants at the\nphase transition point in the two-dimensional q-state Potts model to the 23rd\norder in $1/\\sqrt{q}$ using the finite lattice method. The obtained series\nallow us to give very precise estimates of the cumulants for $q>4$ on the first\norder transition point. The result confirm us the correctness of the conjecture\nby Bhattacharya et al. on the asymptotic behavior of the cumulants for $q \\to\n4_+$.",
        "positive": "Contributions of charm anihilation to the hyperfine splitting in\n  charmonium: In calculations of the hyperfine splitting in charmonium, the contributions\nof the disconnected diagrams is considered small and is typically ignored. We\naim to estimate nonperturbatively the size of the resulting error, which could\npotentially affect the high precision calculations of the charmonium spectrum.\nFollowing our work on the effects of the disconnected diagrams in unquenched\nQCD presented at Lattice 2007, we study the same problem in the quenched case.\nOn dynamical ensembles the disconnected charmonium propagators contain light\nmodes which complicate the extraction of the signal at large distances. In the\nfully quenched case, where there are no such light modes, the interpretation of\nthe signal is simplified. We present results from lattices with $a\\approx 0.09$\nfm and $a\\approx 0.063$ fm."
    },
    {
        "anchor": "L\u00fcscher equation with long-range forces: We derive the modified L\\\"uscher equation in the presence of the long-range\nforce caused by the exchange of a light particle. It is shown that the use of\nthis equation enables one to circumvent the problems related to the strong\npartial-wave mixing and the t-channel sub-threshold singularities. It is also\ndemonstrated that the present method is intrinsically linked to the so-called\nmodified effective-range expansion (MERE) in the infinite volume. A detailed\ncomparison with the two recently proposed alternative approaches is provided.",
        "positive": "Improved Reweighting for QCD Topology at High Temperature: In a previous paper \\cite{Jahn:2018dke} we presented a methodology for\ncomputing the topological susceptibility of QCD at temperatures where it is\nsmall and standard methods fail. Here we improve on this methodology by\nremoving two barriers to the reweighting method's moving between topological\nsectors. We present high-statistics, continuum-extrapolated results for the\nsusceptibility of pure-glue QCD up to $7 T_c$. We show that the susceptibility\nvaries with temperature as $T^{-6.7\\pm 0.3}$ between $T=2.5 T_c$ and $T=7 T_c$,\nin good agreement with expectations based on the dilute instanton gas\napproximation."
    },
    {
        "anchor": "Deconfining Phase Transition on Lattices with Boundaries at Low\n  Temperature: In lattice gauge theory (LGT) equilibrium simulations of QCD are usually\nperformed with periodic boundary conditions (BCs). In contrast to that\ndeconfined regions created in heavy ion collisions are bordered by the confined\nphase. Here we discuss BCs in LGT, which model a cold exterior of the lattice\nvolume. Subsequently we perform Monte Carlo (MC) simulations of pure SU(3) LGT\nwith a thus inspired simple change of BCs using volumes of a size comparable to\nthose typically encountered in the BNL relativistic heavy ion collider (RHIC)\nexperiment. Corrections to the usual LGT results survive in the finite volume\ncontinuum limit and we estimate them as function of the volume size. In\nmagnitude they are found comparable to those of including quarks. As\nobservables we use a pseudocritical temperature, which rises opposite to the\neffect of quarks, and the width of the transition, which broadens similar to\nthe effect of quarks.",
        "positive": "Exact topological density in the lattice Skyrme model: We propose using the Skyrme model on a lattice as an effective field theory\nof meson-baryon interactions. To this end we construct a local topological\ndensity that involves the volumes of tetrahedra in the target space S^3 and we\nmake use of Coxeter's formula for the Schlafli function to implement it. We\ncalculate the mean-square radius of a skyrmion in the three-dimensional Skyrme\nmodel, and find some surprises."
    },
    {
        "anchor": "Determination of Lambda in quenched and full QCD - an update: We present an update on our previous determination of the Lambda parameter in\nQCD. The main emphasis is on results for two flavours of light dynamical\nquarks, where we can now almost double the amount of data used, including\nvalues at smaller lattice spacings. The calculations are performed using $O(a)$\nimproved Wilson fermions. Little change is found to previous numerical values.",
        "positive": "Fermion spectrum in the quenched U(1) chiral Wilson-Yukawa model: Nature of charged fermion state is investigated in the quenched U(1) chiral\nWilson-Yukawa model. Fitting the charged fermion propagator with a single\nhyperbolic cosine does not yield reliable result. On the other hand the\nbehaviour of the propagator including large lattice size dependence is well\ndescribed by the large Wilson-Yukawa coupling expansion, providing strong\nevidence that no charged state exists as an asymptotic particle in this model."
    },
    {
        "anchor": "Extended scaling behavior of the spatially-anisotropic classical XY\n  model in the crossover from three to two dimensions: The bivariate high-temperature expansion of the spin-spin\ncorrelation-function of the three-dimensional classical XY (planar rotator)\nmodel, with spatially-anisotropic nearest-neighbor couplings, is extended from\nthe 10th through the 21st order. The computation is carried out for the\nsimple-cubic lattice, in the absence of magnetic field, in the case in which\nthe coupling strength along the z-axis of the lattice is different from those\nalong the x- and the y-axes. It is then possible to determine accurately the\ncritical temperature as function of the parameter R which characterizes the\ncoupling anisotropy and to check numerically the universality, with respect to\nR, of the critical exponents of the three-dimensional anisotropic system. The\nanalysis of our data also shows that the main predictions of the generalized\nscaling theory for the crossover from the three-dimensional to the\ntwo-dimensional critical behavior are compatible with the series\nextrapolations.",
        "positive": "On reweighting for twisted boundary conditions: We consider the possibility of using reweighting techniques in order to\ncorrect for the breaking of unitarity when twisted boundary conditions are\nimposed on valence fermions in simulations of lattice gauge theories. We start\nby studying the properties of reweighting factors and their variances at\ntree-level. That leads us to the introduction of a factorization for the\nfermionic reweighting determinant. In the numerical, stochastic, implementation\nof the method, we find that the effect of reweighting is negligible in the case\nof large volumes but it is sizeable when the volumes are small and the twisting\nangles are large. More importantly, we find that for un-improved Wilson\nfermions, and in small volumes, the dependence of the critical quark mass on\nthe twisting angle is quite pronounced and results in large violations of the\ncontinuum dispersion relation."
    },
    {
        "anchor": "Systematic errors in extracting nucleon properties from lattice QCD: Form factors of the nucleon have been extracted from experiment with high\nprecision. However, lattice calculations have failed so far to reproduce the\nobserved dependence of form factors on the momentum transfer. We have embarked\non a program to thoroughly investigate systematic effects in lattice\ncalculation of the required three-point correlation functions. Here we focus on\nthe possible contamination from higher excited states and present a method\nwhich is designed to suppress them. Its effectiveness is tested for several\nbaryonic matrix elements, different lattice sizes and pion masses.",
        "positive": "On-shell representations of two-body transition amplitudes: single\n  external current: This work explores scattering amplitudes that couple two-particle systems via\na single external current insertion, $2+\\mathcal{J}\\to 2$. Such amplitudes can\nprovide structural information about the excited QCD spectrum. We derive an\nexact analytic representation for these reactions. From these amplitudes, we\nshow how to rigorously define resonance and bound-state form-factors.\nFurthermore, we explore the consequences of the narrow-width limit of the\namplitudes as well as the role of the Ward-Takahashi identity for conserved\nvector currents. These results hold for any number of two-body channels with no\nintrinsic spin, and a current with arbitrary Lorentz structure and quantum\nnumbers. This work and the existing finite-volume formalism provide a complete\nframework for determining this class of amplitudes from lattice QCD."
    },
    {
        "anchor": "Chiral symmetry and O(a) improvement in lattice QCD: The dominant cutoff effects in lattice QCD with Wilson quarks are\nproportional to the lattice spacing a. In particular, the isovector axial\ncurrent satisfies the PCAC relation only up to such effects. Following a\nsuggestion of Symanzik, they can be cancelled by adding local O(a) correction\nterms to the action and the axial current. We here address a number of\ntheoretical issues in connection with the O(a) improvement of lattice QCD and\nthen show that chiral symmetry can be used to fix the coefficients multiplying\nthe correction terms.",
        "positive": "Spontaneous symmetry breaking via inhomogeneities and the differential\n  surface tension: We discuss spontaneously broken quantum field theories with a continuous\nsymmetry group via the constraint effective potential. Employing lattice\nsimulations with constrained values of the order parameter, we demonstrate\nexplicitly that the path integral is dominated by inhomogeneous field\nconfigurations and that these are unambiguously related to the flatness of the\neffective potential in the broken phase. We determine characteristic features\nof these inhomogeneities, including their topology and the scaling of the\nassociated excess energy with their size. Concerning the latter we introduce\nthe differential surface tension -- the generalization of the concept of a\nsurface tension pertaining to discrete symmetries. Within our approach,\nspontaneous symmetry breaking is captured merely via the existence of\ninhomogeneities, i.e. without the inclusion of an explicit breaking parameter\nand a careful double limiting procedure to define the order parameter. While\nhere we consider the three-dimensional $O(2)$ model, we also elaborate on\npossible implications of our findings for the chiral limit of QCD."
    },
    {
        "anchor": "Nuclear Physics and Lattice QCD: Lattice QCD is progressing toward being able to impact our understanding of\nnuclei and nuclear processes. I discuss areas of nuclear physics that are\nbecoming possible to explore with lattice QCD, the techniques that are\ncurrently available and the status of numerical explorations.",
        "positive": "Lattice study of sphaleron transitions in a 2D O(3) sigma model: A lattice approach is developed to measure the sphaleron free energy. Its\nfeasibility is demonstrated through a Monte Carlo study of the two-dimensional\nO(3) sigma model."
    },
    {
        "anchor": "First results from 2+1-Flavor Domain Wall QCD: Mass Spectrum, Topology\n  Change and Chiral Symmetry with $L_s=8$: We present results for the static interquark potential, light meson and\nbaryon masses, and light pseudoscalar meson decay constants obtained from\nsimulations of domain wall QCD with one dynamical flavour approximating the $s$\nquark, and two degenerate dynamical flavours with input bare masses ranging\nfrom $m_s$ to $m_s/4$ approximating the $u$ and $d$ quarks. We compare these\nquantities obtained using the Iwasaki and DBW2 improved gauge actions, and\nactions with larger rectangle coefficients, on $16^3\\times32$ lattices. We seek\nparameter values at which both the chiral symmetry breaking residual mass due\nto the finite lattice extent in the fifth dimension and the Monte Carlo time\nhistory for topological charge are acceptable for this set of quark masses at\nlattice spacings above 0.1 fm. We find that the Iwasaki gauge action is best,\ndemonstrating the feasibility of using QCDOC to generate ensembles which are\ngood representations of the QCD path integral on lattices of up to 3 fm in\nspatial extent with lattice spacings in the range 0.09-0.13 fm. Despite large\nresidual masses and a limited number of sea quark mass values with which to\nperform chiral extrapolations, our results for light hadronic physics scale and\nagree with experimental measurements within our statistical uncertainties.",
        "positive": "Computing and deflating eigenvalues while solving multiple right hand\n  side linear systems in Quantum Chromodynamics: We present a new algorithm that computes eigenvalues and eigenvectors of a\nHermitian positive definite matrix while solving a linear system of equations\nwith Conjugate Gradient (CG). Traditionally, all the CG iteration vectors could\nbe saved and recombined through the eigenvectors of the tridiagonal projection\nmatrix, which is equivalent theoretically to unrestarted Lanczos. Our algorithm\ncapitalizes on the iteration vectors produced by CG to update only a small\nwindow of vectors that approximate the eigenvectors. While this window is\nrestarted in a locally optimal way, the CG algorithm for the linear system is\nunaffected. Yet, in all our experiments, this small window converges to the\nrequired eigenvectors at a rate identical to unrestarted Lanczos. After the\nsolution of the linear system, eigenvectors that have not accurately converged\ncan be improved in an incremental fashion by solving additional linear systems.\nIn this case, eigenvectors identified in earlier systems can be used to\ndeflate, and thus accelerate, the convergence of subsequent systems. We have\nused this algorithm with excellent results in lattice QCD applications, where\nhundreds of right hand sides may be needed. Specifically, about 70 eigenvectors\nare obtained to full accuracy after solving 24 right hand sides. Deflating\nthese from the large number of subsequent right hand sides removes the dreaded\ncritical slowdown, where the conditioning of the matrix increases as the quark\nmass reaches a critical value. Our experiments show almost a constant number of\niterations for our method, regardless of quark mass, and speedups of 8 over\noriginal CG for light quark masses."
    },
    {
        "anchor": "Pion distribution amplitude from Euclidean correlation functions:\n  Exploring universality and higher-twist effects: Building upon our recent study arXiv:1709.04325, we investigate the\nfeasibility of calculating the pion distribution amplitude from suitably chosen\nEuclidean correlation functions at large momentum. We demonstrate in this work\nthe advantage of analyzing several correlation functions simultaneously and\nextracting the pion distribution amplitude from a global fit. This approach\nalso allows us to study higher-twist corrections, which are a major source of\nsystematic error. Our result for the higher-twist parameter $\\delta^\\pi_2$ is\nin good agreement with estimates from QCD sum rules. Another novel element is\nthe use of all-to-all propagators, calculated using stochastic estimators,\nwhich enables an additional volume average of the correlation functions,\nthereby reducing statistical errors.",
        "positive": "Conformal Window and Correlation Functions in Lattice Conformal QCD: We discuss various aspects of Conformal Field Theories on the Lattice. We\nmainly investigate the SU(3) gauge theory with N_f degenerate fermions in the\nfundamental representation, employing the one-plaquette gauge action and the\nWilson fermion action.\n  First we make a brief review of our previous works and thereby clarify the\nreason why we conjecture that the conformal window is 7 le N_f le 16.\n  Secondly, we introduce a new concept, \"conformal theories with an IR cutoff\"\nand point out that any numerical simulation on a lattice is bounded by an IR\ncutoff Lambda_{IR}. Then we make predictions that when N_f is within the\nconformal window, the propagator of a meson G(t) behaves at large t, as G(t) =\nc exp(-m_H t)/t^alpha, that is, a modified Yukawa-type decay form, instead of\nthe usual exponential decay form in the small quark mass region. This holds on\nan any lattice for any coupling constant g, as far as g is between 0 and g^*,\nwhere g^* is the IR fixed point. We verify that numerical results really\nsatisfy the predictions for the N_f=7 case and the N_f=16 case.\n  Thirdly, we discuss small number of flavors (N_f=2 sim 6) QCD at finite\ntemperatures. We point out theoretically and verify numerically that the\ncorrelation functions at T/T_c > 1 exhibit the characteristics of the conformal\nfunction with IR cutoff, an exponential decay with power correction.\n  Further, we observe our data are consistent with the picture that the N_f=7\ncase and the N_f=2 at T sim 2 T_c case are close to the meson unparticle model,\nand we estimate gamma^* = 1.2(1). On the other hand, the N_f=16 case and the\nN_f=2 at T= 10^2 sim 10^5 Tc cases are close to a free state in the Z(3)\ntwisted vacuum. The results give clues for long standing issues such as slow\napproach of the free energy to the Stefan-Boltzmann ideal gas limit."
    },
    {
        "anchor": "Non-perturbative renormalization of quark and gluon operators using a\n  gauge-invariant scheme: We present preliminary results for the renormalization functions (RFs) of a\nnumber of quark and gluon operators studied in lattice QCD using a\ngauge-invariant renormalization scheme (GIRS). GIRS is a variant of the\ncoordinate-space renormalization prescription, in which Green's functions of\ngauge-invariant operators are calculated in position space. A novel aspect is\nthat summations over different time slices of the positions of the operators\nare employed in order to reduce the statistical noise in lattice simulations.\nWe test the reliability of this scheme by calculating RFs for the vector\none-derivative quark bilinear operator, which enters the average momentum\nfraction of the nucleon. We use $N_f=4$ degenerate twisted mass clover-improved\nfermion ensembles of different volumes and lattice spacings. We also present\nfirst results of applying GIRS when operator mixing occurs: the mixing\ncoefficients of the gluon and quark singlet energy-momentum tensor operators\nare evaluated by imposing appropriate renormalization conditions on the\nlattice.",
        "positive": "Extended study for unitary fermions on a lattice using the cumulant\n  expansion technique: A recently developed lattice method for large numbers of strongly interacting\nnonrelativistic fermions exhibits a heavy tail in the distributions of\ncorrelators for large Euclidean time {\\tau} and large number of fermions N,\nwhich only allows the measurement of ground state energies for a limited number\nof fermions using standard techniques. In such cases, it is suggested that\nmeasuring the log of the correlator is more efficient, and a cumulant expansion\nof this quantity can be exactly related to the correlation function. The\ncumulant expansion technique allows us to determine the ground state energies\nof up to 66 unpolarized unitary fermions on lattices as large as\n72$\\times$14^3, and up to 70 unpolarized unitary fermions trapped in a harmonic\npotential on lattices as large as 72$\\times$64^3. We have also improved our\nlattice action with a Galilean invariant form for the four-fermion interaction,\nwhich results in predictive volume scaling of the lowest energy of three\nfermions in a periodic box and in good agreement of our results for N \\leq 6\ntrapped unitary fermions with those from other benchmark calculations."
    },
    {
        "anchor": "Glueball masses in the large N limit: The lowest-lying glueball masses are computed in SU($N$) gauge theory on a\nspacetime lattice for constant value of the lattice spacing $a$ and for $N$\nranging from 3 to 8. The lattice spacing is fixed using the deconfinement\ntemperature at temporal extension of the lattice $N_T = 6$. The calculation is\nconducted employing in each channel a variational ansatz performed on a large\nbasis of operators that includes also torelon and (for the lightest states)\nscattering trial functions. This basis is constructed using an automatic\nalgorithm that allows us to build operators of any size and shape in any\nirreducible representation of the cubic group. A good signal is extracted for\nthe ground state and the first excitation in several symmetry channels. It is\nshown that all the observed states are well described by their large $N$\nvalues, with modest ${\\cal O}(1/N^2)$ corrections. In addition spurious states\nare identified that couple to torelon and scattering operators. As a byproduct\nof our calculation, the critical couplings for the deconfinement phase\ntransition for N=5 and N=7 and temporal extension of the lattice $N_T=6$ are\ndetermined.",
        "positive": "Isospin-breaking corrections to weak decays: the current status and a\n  new infrared improvement: We provide an overview of the current state of lattice calculations\nconcerning isospin-breaking corrections in weak decays, focusing in particular\non leptonic decays of light pseudoscalar mesons. We examine the two currently\nexisting calculations, placing a particular emphasis on the role of\nelectromagnetic finite-volume corrections. Given the large systematic\nuncertainty associated with such corrections, we propose a novel method to\nimprove the finite-volume scaling of leptonic decay rates and other hadronic\nobservables, like hadron masses and the hadronic vacuum polarization\ncontribution to the muon $g{-}2$. We introduce a new prescription for the QED\naction, referred to as QED$_\\mathrm{r}$, which effectively removes\nfinite-volume corrections at $\\mathcal{O}(1/L^3)$ and consequently shifts the\nsystematic uncertainty to a higher order. The specifics of this action, the\npractical implementation of the infrared improvement, and the ongoing numerical\ntests are also discussed."
    },
    {
        "anchor": "Renormalizability of the gradient flow in the 2D $O(N)$ non-linear sigma\n  model: It is known that the gauge field and its composite operators evolved by the\nYang--Mills gradient flow are ultraviolet (UV) finite without any\nmultiplicative wave function renormalization. In this paper, we prove that the\ngradient flow in the 2D $O(N)$ non-linear sigma model possesses a similar\nproperty: The flowed $N$-vector field and its composite operators are UV finite\nwithout multiplicative wave function renormalization. Our proof in all orders\nof perturbation theory uses a $(2+1)$-dimensional field theoretical\nrepresentation of the gradient flow, which possesses local gauge invariance\nwithout gauge field. As application of the UV finiteness of the gradient flow,\nwe construct the energy--momentum tensor in the lattice formulation of the\n$O(N)$ non-linear sigma model that automatically restores the correct\nnormalization and the conservation law in the continuum limit.",
        "positive": "The strange quark contribution to the spin of the nucleon: Quark line disconnected matrix elements of an operator, such as the axial\ncurrent, are difficult to compute on the lattice. The standard method uses a\nstochastic estimator of the operator, which is generally very noisy. We discuss\nand develop further our alternative approach using the Feynman-Hellmann theorem\nwhich involves only evaluating two-point correlation functions. This is applied\nto computing the contribution of the quark spin to the nucleon and in\nparticular for the strange quark. In this process we also pay particular\nattention to the development of an SU(3) flavour breaking expansion for singlet\noperators."
    },
    {
        "anchor": "Glueballs at Physical Pion Mass: We study glueballs on two $N_f=2+1$ RBC/UKQCD gauge ensembles with physical\nquark masses at two lattice spacings. The statistical uncertainties of the\nglueball correlation functions are considerably reduced through the cluster\ndecomposition error reduction (CDER) method. The Bethe-Salpeter wave functions\nare obtained for the scalar, tensor and pseudoscalar glueballs by using\nspatially extended glueball operators defined through the gauge potential\n$A_\\mu(x)$ in the Coulomb gauge. These wave functions show similar features of\nnon-relativistic two-gluon systems, and they are used to optimize the signals\nof the related correlation functions at the early time regions. Consequently,\nthe ground state masses can be extracted precisely. To the extent that the\nexcited state contamination is not important, our calculation gives glueball\nmasses at the physical pion mass for the first time.",
        "positive": "The leading hadronic contribution to the running of the Weinberg angle\n  using covariant coordinate-space methods: We present a preliminary study of the leading hadronic contribution to the\nrunning of the Weinberg angle $\\theta_{\\mathrm{W}}$. The running is extracted\nfrom the correlation function of the electromagnetic current with the vector\npart of the weak neutral current using both the standard time-momentum\nrepresentation method and the Lorentz-covariant coordinate-space method\nrecently introduced by Meyer. Both connected and disconnected contributions\nhave been computed on $N_{\\mathrm{f}}=2+1$ non-perturbatively $O(a)$-improved\nWilson fermions configurations from the CLS initiative. Similar covariant\ncoordinate-space methods can be used to compute the leading hadronic\ncontribution to the anomalous magnetic moment of the muon $(g-2)_\\mu$ and to\nthe running of the QED coupling $\\alpha$."
    },
    {
        "anchor": "Genuine Symmetry of Staggered Fermion: We present a new formulation of the staggered fermion on the D-dimensional\nlattice based on the SO(2D) Clifford algebra, which is naturally present in the\naction. The action of the massless staggered fermion is invariant under the\ndiscrete rotation and the SO(2D) chiral and other discrete transformations.\n  From transformation properties of the fermion, we find two local meson\noperators (one scalar and one pseudoscalar) in addition to two standard meson\noperators.",
        "positive": "Progress on lattice QCD algorithms: I review recent progress on algorithms for calculating quark propagators and\nfor simulating full QCD."
    },
    {
        "anchor": "The gradient flow in $\u03bb\u03c6^{4}$ theory: A gradient flow equation for $\\lambda\\phi^{4}$ theory in $D=4$ is formulated.\nIn this scheme the gradient flow equation is written in terms of the\nrenormalized probe variable $\\Phi(t,x)$ and renormalized parameters $m^{2}$ and\n$\\lambda$ in a manner analogous to the higher derivative regularization. No\nextra divergence is induced in the interaction of the probe variable\n$\\Phi(t,x)$ and the 4-dimensional dynamical variable $\\phi(x)$ which is defined\nin renormalized perturbation theory. The finiteness to all orders in\nperturbation theory is established by power counting argument in the context of\n$D+1$ dimensional field theory. This illustrates that one can formulate the\ngradient flow for the simple but important $\\lambda\\phi^{4}$ theory in addition\nto the well-known Yang-Mills flow, and it shows the generality of the gradient\nflow for a wider class of field theory.",
        "positive": "Background field method and nonrelativistic QED matching: We discuss the resolution of an inconsistency between lattice background\nfield methods and nonrelativistic QED matching conditions. In particular, we\nshow that lack of on-shell conditions in lattice QCD with time-dependent\nbackground fields generally requires that certain operators related by\nequations of motion should be retained in an effective field theory to\ncorrectly describe the behavior of Green's functions. The coefficients of such\noperators in a nonrelativistic hadronic theory are determined by performing a\nrobust nonrelativistic expansion of QED for relativistic scalar and spin-half\nhadrons including nonminimal electromagnetic couplings. Provided that\nnonrelativistic QED is augmented with equation-of-motion operators, we find\nthat the background field method can be reconciled with the nonrelativistic QED\nmatching conditions without any inconsistency. We further investigate whether\nnonrelativistic QED can be employed in the analysis of lattice QCD correlation\nfunction in background fields, but we are confronted with difficulties.\nInstead, we argue that the most desirable approach is a hybrid one which relies\non a relativistic hadronic theory with operators chosen based on their\nrelevance in the nonrelativistic limit. Using this hybrid framework, we obtain\npractically useful forms of correlation functions for scalar and spin-half\nhadrons in uniform electric and magnetic fields."
    },
    {
        "anchor": "The Yang-Mills vacuum wave functional thirty-five years later: The first paper attempting direct calculation of the Yang-Mills vacuum wave\nfunctional was published by Greensite in 1979. I review some recent results of\nthe determination of the vacuum wave functional in Monte Carlo simulations of\nSU(2) lattice gauge theory.",
        "positive": "The Isgur-Wise Function from the Lattice: We calculate the Isgur-Wise function by measuring the elastic scattering\namplitude of a $D$ meson in the quenched approximation on a $24^3\\times48$\nlattice at $\\beta=6.2$, using an $O(a)$-improved fermion action. Fitting the\nresulting chirally-extrapolated Isgur-Wise function to Stech's\nrelativistic-oscillator parametrization, we obtain a slope parameter\n$\\rho^2=1.2+7-3. We then use this result, in conjunction with heavy-quark\nsymmetry, to extract $V_{cb}$\\ from the experimentally measured $\\bar B\\to\nD^*l\\bar\\nu\\,$\\ differential decay width. We find\n$|V_{cb}|\\sqrt{\\tau_B/1.48{\\mathrm ps}}= 0.038 +2-2 +8-3, where the first set\nof errors is due to experimental uncertainties, while the second is due to the\nuncertainty in our lattice determination of $\\rho^2$."
    },
    {
        "anchor": "Isoscalar mesons upon unbreaking of chiral symmetry: In a dynamical lattice simulation with the overlap Dirac operator and $N_f=2$\nmass degenerate quarks we study all possible $J=0$ and $J=1$ correlators upon\nexclusion of the low lying \"quasi-zero\" modes from the valence quark\npropagators. After subtraction of a small amount of such Dirac eigenmodes all\ndisconnected contributions vanish and all possible point-to-point $J=0$\ncorrelators with different quantum numbers become identical, signaling a\nrestoration of the $SU(2)_L \\times SU(2)_R \\times U(1)_A$. The original ground\nstate of the $\\pi$ meson does not survive this truncation, however. In\ncontrast, in the $I=0$ and $I=1$ channels for the $J=1$ correlators the ground\nstates have a very clean exponential decay. All possible chiral multiplets for\nthe $J=1$ mesons become degenerate, indicating a restoration of an $SU(4)$\nsymmetry of the dynamical QCD-like string.",
        "positive": "Calibration of Smearing and Cooling Algorithms in SU(3)-Color Gauge\n  Theory: The action and topological charge are used to determine the relative rates of\nstandard cooling and smearing algorithms in pure SU(3)-color gauge theory. We\nconsider representative gauge field configurations on $16^3\\times 32$ lattices\nat $\\beta=5.70$ and $24^3\\times 36$ lattices at $\\beta=6.00$. We find the\nrelative rate of variation in the action and topological charge under various\nalgorithms may be succinctly described in terms of simple formulae. The results\nare in accord with recent suggestions from fat-link perturbation theory."
    },
    {
        "anchor": "Lattice real-time simulations with learned optimal kernels: We present a simulation strategy for the real-time dynamics of quantum\nfields, inspired by reinforcement learning. It builds on the complex Langevin\napproach, which it amends with system specific prior information, a necessary\nprerequisite to overcome this exceptionally severe sign problem. The\noptimization process underlying our machine learning approach is made possible\nby deploying inherently stable solvers of the complex Langevin stochastic\nprocess and a novel optimality criterion derived from insight into so-called\nboundary terms. This conceptual and technical progress allows us to both\nsignificantly extend the range of real-time simulations in 1+1d scalar field\ntheory beyond the state-of-the-art and to avoid discretization artifacts that\nplagued previous real-time field theory simulations. Limitations of and\npromising future directions are discussed.",
        "positive": "Low-Energy QCD in the Delta Regime: We investigate properties of low-energy QCD in a finite spatial volume, but\nwith arbitrary temperature. In the limit of small temperature and small cube\nsize compared to the pion Compton wavelength, Leutwyler has shown that the\neffective theory describing low-energy QCD reduces to that of quantum mechanics\non the coset manifold, which is the so-called delta regime of chiral\nperturbation theory. We solve this quantum mechanics analytically for the case\nof a $U(1)_L \\times U(1)_R$ subgroup of chiral symmetry, and numerically for\nthe case of $SU(2)_L \\times SU(2)_R$. We utilize the quantum mechanical\nspectrum to compute the mass gap and chiral condensate, and investigate\nsymmetry restoration in a finite spatial volume as a function of temperature.\nBecause we obtain the spectrum for non-zero values of the quark mass, we are\nable to interpolate between the rigid rotor limit, which emerges at vanishing\nquark mass, and the harmonic approximation, which is referred to as the\np-regime. We find that the applicability of perturbation theory about the rotor\nlimit largely requires lighter-than-physical quarks. As a stringent check of\nour results, we raise the temperature to that of the inverse cube size. When\nthis condition is met, the quantum mechanics reduces to a matrix model. The\ncondensate we obtain in this limit agrees with that determined analytically in\nthe epsilon regime."
    },
    {
        "anchor": "Removal of Z_3-symmetry breaking from Fermionic Determinants: We consider prescriptions that are free from the direct charge-screening\neffects by quark loops and enable us to clarify the confining nature of a\nvacuum. We test two candidates for an order parameter, a Polyakov loop ($P$)\nevaluated in zero-triality backgrounds and fermionic determinants (${\\mathcal\nD}_{1,2}$) with non-zero triality. Especially, ${\\mathcal D}_{1,2}$ has very\nsmall fluctuations in comparison with a Polyakov loop in zero-triality sector,\nand seems to well reflect the characteristic of a vacuum. Such prescriptions\ncould be still usable for the clarification of the confinement property of a\nvacuum.",
        "positive": "Light Hadron Spectroscopy: Recent developments in calculations of the light hadron spectrum are\nreviewed. Particular emphasis is placed on discussion of to what extent the\nquenched spectrum agrees with experiment. Recent progress, both for quenched\nand full QCD, in reducing scaling violation with the use of improved actions is\npresented."
    },
    {
        "anchor": "Topology of the Yang-Mills Configuration space: It will be described how to uniquely fix the gauge using Coulomb gauge\nfixing, avoiding the problem of Gribov copies. The fundamental modular domain,\nwhich represents a one-to-one representation of the set of gauge invariant\ndegrees of freedom, is a bounded convex subset of the trans- verse gauge\nfields. Boundary identifications are the only remnants of the Gribov copies,\nand carry all the information about the topology of the Yang-Mills\nconfiguration space. Conversely, the known topology can be shown to imply that\n(on a set of measure zero on the boundary) some points of the boundary coincide\nwith the Gribov horizon. For the low-lying energies, wavefunctionals can be\nshown to spread out \"across\" certain parts of these boundaries. This is how the\ntopology of Yang-Mills configuration space has an essential influence on the\nlow-lying spectrum, in a situation where these non- perturbative effects are\nnot exponentially suppressed.\n  This write-up is a short summary, with adequate references, where details on\nmost of the material I have presented can be found. However, not published\nbefore, is a new observation concerning Henyey's gauge copies.",
        "positive": "Renormalisation of the tensor current in lattice QCD and the $J/\u03c8$\n  tensor decay constant: Lattice QCD calculations of form factors for rare Standard Model processes\nsuch as $B \\to K \\ell^+ \\ell^-$ use tensor currents that require\nrenormalisation. These renormalisation factors, $Z_T$, have typically been\ncalculated within perturbation theory and the estimated uncertainties from\nmissing higher order terms are significant. Here we study tensor current\nrenormalisation using lattice implementations of momentum-subtraction schemes.\nSuch schemes are potentially more accurate but have systematic errors from\nnonperturbative artefacts. To determine and remove these condensate\ncontributions we calculate the ground-state charmonium tensor decay constant,\n$f_{J/\\psi}^T$, which is also of interest in beyond the Standard Model studies.\nWe obtain $f_{J/\\psi}^T(\\bar{\\text{MS}}, 2\\ \\mathrm{GeV})=0.3927(27)$ GeV, with\nratio to the vector decay constant of 0.9569(52), significantly below 1. We\nalso give $Z_T$ factors, converted to the $\\bar{\\mathrm{MS}}$ scheme, corrected\nfor condensate contamination. This contamination reaches 1.5\\% at a\nrenormalisation scale of 2 GeV (in the preferred RI-SMOM scheme) and so must be\nremoved for accurate results."
    },
    {
        "anchor": "Four-Quark Binding Energies from SU(2) Lattice Monte Carlo: Energies of four-quark systems have been extracted in a static quenched SU(2)\nlattice Monte Carlo calculation for six different geometries, both planar and\nnon-planar, with $\\beta=2.4$ and lattice size $16^3\\times 32$. In all cases, it\nis found that the binding energy is greatly enhanced when the four quarks can\nbe partitioned in two ways with comparable energies. Also it is shown that the\nenergies of the four-quark states cannot be understood simply in terms of\ntwo-quark potentials.",
        "positive": "The exact equivalence of the one-flavour lattice Thirring model with\n  Wilson fermions to a two-colour loop model: Within Euclidean lattice field theory an exact equivalence between the\none-flavour 2D Thirring model with Wilson fermions and Wilson parameter $r = 1$\nto a two-colour loop model on the square lattice is established. For\nnon-interacting fermions this model reduces to an exactly solved loop model\nwhich is known to be a free fermion model. The two-colour loop model equivalent\nto the Thirring model can also be understood as a 4-state 49-vertex model."
    },
    {
        "anchor": "Angular Momentum on the Lattice: The Case of Non-Zero Linear Momentum: The irreducible representations (IRs) of the double cover of the Euclidean\ngroup with parity in three dimensions are subduced to the corresponding cubic\nspace group. The reduction of these representations gives the mapping of\ncontinuum angular momentum states to the lattice in the case of non-zero linear\nmomentum. The continuous states correspond to lattice states with the same\nmomentum and continuum rotational quantum numbers decompose into those of the\nIRs of the little group of the momentum vector on the lattice. The inverse\nmapping indicates degeneracies that will appear between levels of different\nlattice IRs in the continuum limit, recovering the continuum angular momentum\nmultiplets. An example of this inverse mapping is given for the case of the\n``moving'' isotropic harmonic oscillator.",
        "positive": "Random matrix theory of unquenched two-colour QCD with nonzero chemical\n  potential: We solve a random two-matrix model with two real asymmetric matrices whose\nprimary purpose is to describe certain aspects of quantum chromodynamics with\ntwo colours and dynamical fermions at nonzero quark chemical potential mu. In\nthis symmetry class the determinant of the Dirac operator is real but not\nnecessarily positive. Despite this sign problem the unquenched matrix model\nremains completely solvable and provides detailed predictions for the Dirac\noperator spectrum in two different physical scenarios/limits: (i) the\nepsilon-regime of chiral perturbation theory at small mu, where mu^2 multiplied\nby the volume remains fixed in the infinite-volume limit and (ii) the\nhigh-density regime where a BCS gap is formed and mu is unscaled. We give\nexplicit examples for the complex, real, and imaginary eigenvalue densities\nincluding Nf=2 non-degenerate flavours. Whilst the limit of two degenerate\nmasses has no sign problem and can be tested with standard lattice techniques,\nwe analyse the severity of the sign problem for non-degenerate masses as a\nfunction of the mass split and of mu.\n  On the mathematical side our new results include an analytical formula for\nthe spectral density of real Wishart eigenvalues in the limit (i) of weak\nnon-Hermiticity, thus completing the previous solution of the corresponding\nquenched model of two real asymmetric Wishart matrices."
    },
    {
        "anchor": "Relating Quark Confinement and Chiral Symmetry Breaking in QCD: We study the relation between quark confinement and chiral symmetry breaking\nin QCD. Using lattice QCD formalism, we analytically express the various\n\"confinement indicators\", such as the Polyakov loop, its fluctuations, the\nWilson loop, the inter-quark potential and the string tension, in terms of the\nDirac eigenmodes. In the Dirac spectral representation, there appears a power\nof the Dirac eigenvalue $\\lambda_n$ such as $\\lambda_n^{N_t-1}$, which behaves\nas a reduction factor for small $\\lambda_n$. Consequently, since this reduction\nfactor cannot be cancelled, the low-lying Dirac eigenmodes give negligibly\nsmall contribution to the confinement quantities,while they are essential for\nchiral symmetry breaking. These relations indicate no direct, one-to-one\ncorrespondence between confinement and chiral symmetry breaking in QCD. In\nother words, there is some independence of quark confinement from chiral\nsymmetry breaking, which can generally lead to different transition\ntemperatures/densities for deconfinement and chiral restoration. We also\ninvestigate the Polyakov loop in terms of the eigenmodes of the Wilson, the\nclover and the domain-wall fermion kernels, respectively, and find the similar\nresults. The independence of quark confinement from chiral symmetry breaking\nseems to be natural, because confinement is realized independently of quark\nmasses and heavy quarks are also confined even without the chiral symmetry.",
        "positive": "Solution of the sign problem in the Potts model at fixed fermion number: We consider the heavy-dense limit of QCD at finite fermion density in the\ncanonical formulation and approximate it by a 3-state Potts model. In the\nstrong coupling limit, the model is free of the sign problem. Away from the\nstrong coupling, the sign problem is solved by employing a cluster algorithm\nwhich allows to average each cluster over the Z(3) sectors. Improved estimators\nfor physical quantities can be constructed by taking into account the triality\nof the clusters, that is, their transformation properties with respect to Z(3)\ntransformations."
    },
    {
        "anchor": "Low-temperature expansion and perturbation theory in 2D models with\n  unbroken symmetry: a new approach: A new method of constructing a weak coupling expansion of two dimensional\n(2D) models with an unbroken continuous symmetry is developed. The method is\nbased on an analogy with the abelian XY model, respects the Mermin-Wagner (MW)\ntheorem and uses a link representation of the partition and correlation\nfunctions. An expansion of the free energy and of the correlation functions at\nsmall temperatures is performed and first order coefficients are calculated\nexplicitly. They are shown to coincide with the results of the conventional\nperturbation theory. We discuss an applicability of our method to analysis of\nuniformity of the low-temperature expansion.",
        "positive": "Suppressing dislocations in normalized hypercubic smearing: Normalized hypercubic smearing improves the behavior of dynamical\nWilson-clover fermions, but has the unwanted side effect that it can\noccasionally produce spikes in the fermion force. These spikes originate in the\nchain rule connecting the derivative with respect to the smeared links to the\nderivative with respect to the dynamical links, and are associated with the\npresence of dislocations in the dynamical gauge field. We propose and study an\naction designed to suppress these dislocations. We present evidence for\nimproved performance of the hybrid Monte Carlo algorithm. A side benefit is\nimprovement in the properties of valence chiral fermions."
    },
    {
        "anchor": "Multi-hadron states in Lattice QCD spectroscopy: The ability to reliably measure the energy of an excited hadron in Lattice\nQCD simulations hinges on the accurate determination of all lower-lying\nenergies in the same symmetry channel. These include not only single-particle\nenergies, but also the energies of multi-hadron states. This talk deals with\nthe determination of multi-hadron energies in Lattice QCD. The\ngroup-theoretical derivation of lattice interpolating operators that couple\noptimally to multi-hadron states is described. We briefly discuss recent\nalgorithmic developments which allow for the efficient implementation of these\noperators in software, and present numerical results from the Hadron Spectrum\nCollaboration.",
        "positive": "On the Phase Diagram of the SU(2) Adjoint Higgs Model in 2+1 Dimensions: The phase diagram is investigated for SU(2) lattice gauge theory in d=3,\ncoupled to adjoint scalars. For small values of the quartic scalar coupling,\nlambda, the transition separating Higgs and confinement phases is found to be\nfirst-order, in agreement with earlier work by Nadkarni. The surface of\nsecond-order transitions conjectured by Nadkarni, however, is shown instead to\ncorrespond to crossover behaviour. This conclusion is based on a finite size\nanalysis of the scalar mass and susceptibility. The nature of the phase\ntransition at the termination of first-order behaviour is investigated and we\nfind evidence for a critical point at which the scalar mass vanishes. The\nphoton mass and confining string tension are measured and are found to be\nnegligibly small in the Higgs phase. This is correlated with the very small\ndensity of magnetic monopoles in the Higgs phase. The string tension and photon\nmass rise rapidly as the crossover is traversed towards the symmetric phase."
    },
    {
        "anchor": "Leptonic widths of heavy quarkonia: S-Wave QCD/NRQCD matching\n  coefficients for the electromagnetic vector annihilation current at O(alpha_s\n  v^2): We construct the S-wave part of the electromagnetic vector annihilation\ncurrent to O(alpha_s v^2)$ on the lattice for heavy quarks whose dynamics are\ndescribed by the NRQCD action, where v is the non-relativistic quark velocity.\nThe lattice vector current for QQbar annihilation is expressed as a linear\ncombination of lattice operators with quantum numbers L=0, J^P=1^-, and the\ncoefficients are determined by matching this lattice current to the\ncorresponding continuum current in QCD to O(v^2) to one-loop. The annihilation\nchannel gives a complex amplitude and a proper choice for the contours of\nintegration is needed; a simple Wick rotation is not possible. In this way, and\nwith a careful choice of subtraction functions in the numerical integration,\nthe Coulomb-exchange and infrared singularities appearing in the amplitudes are\nsuccessfully treated. The matching coefficients are given as a function of the\nheavy quark mass Ma in lattice units. An automated vertex generation program\nwritten in Python is employed, allowing us to use a realistic NRQCD action and\nan improved gluon lattice action. A change in the definition of either action\nis easily accommodated in this procedure. The final result is applicable to the\nelectromagnetic decays of heavy quarkonia, notably the Upsilon meson.",
        "positive": "The Color--Flavor Transformation of induced QCD: The color-flavor transformation is applied to the U(N) lattice gauge model,\nin which the gauge theory is induced by a heavy chiral scalar field sitting on\nlattice sites. The flavor degrees of freedom can encompass several\n`generations' of the auxiliary field, and for each generation, remaining\nindices are associated with the elementary plaquettes touching the lattice\nsite. The effective, color-flavor transformed theory is expressed in terms of\ngauge singlet matrix fields carried by lattice links. The effective action is\nanalyzed for a hypercubic lattice in arbitrary dimension. The saddle points\nequations of the model in the large-N limit are discussed."
    },
    {
        "anchor": "Large-N spacetime reduction and the sign and silver-blaze problems of\n  dense QCD: We study the spacetime-reduced (Eguchi-Kawai) version of large-N QCD with\nnonzero chemical potential. We explore a method to suppress the sign\nfluctuations of the Dirac determinant in the hadronic phase; the method employs\na re-summation of gauge configurations that are related to each other by center\ntransformations. We numerically test this method in two dimensions, and find\nthat it successfully solves the silver-blaze problem. We analyze the system\nfurther, and measure its free energy F, the average phase theta of its Dirac\ndeterminant, and its chiral condensate <psi-bar-psi>. We show that F and\n<psi-bar-psi> are independent of mu in the hadronic phase but that, as chiral\nperturbation theory predicts, the quenched chiral condensate drops from its\nmu=0 value when mu~(pion mass)/2. Finally, we find that the distribution of\ntheta qualitatively agrees with further, more recent, predictions from chiral\nperturbation theory.",
        "positive": "Five-quark picture of Lambda(1405) in anisotropic lattice QCD: Five-quark (5Q) picture of Lambda(1405) is studied using quenched lattice QCD\nwith an exotic 5Q operator of N\\bar{K} type. To discreminate mere N\\bar{K} and\n\\Sigma\\pi scattering states, Hybrid Boundary Condition (HBC), a\nflavor-dependent boundary condition, is imposed on the quark fields along\nspatial direction. 5Q mass m_{5Q}\\simeq 1.89 GeV is obtained after the chiral\nextrapolation to the physical quark mass region, which is too heavy to be\nidentified with Lambda(1405). Then, Lambda(1405) seems neither a pure 3Q state\nnor a pure 5Q state, and therefore we present an interesting possibility that\nLambda(1405) is a mixed state of 3Q and 5Q states."
    },
    {
        "anchor": "Generalized form factors of the pion and kaon using twisted mass\n  fermions: We present an update on our lattice calculations of the Mellin moments of\nPDFs and GPDs for the pion and kaon, using momentum-boosted meson states. In\nparticular, we focus on the calculation of the scalar and tensor local\noperators, and the vector operator with up to three-covariant derivatives. The\ncorresponding matrix elements allow us to extract the scalar and tensor\ncharges, as well as $\\langle x^n \\rangle$ with $n=1,2,3$. In addition, we\nintroduce momentum transfer between the initial and final meson state that\nleads to the scalar, vector, and tensor form factors, and the generalized form\nfactors up to three covariant derivatives. The above results are obtained using\ntwo ensembles of maximally twisted mass fermions with clover improvement with\ntwo degenerate light, a strange, and a charm quark $(N_f=2+1+1)$ at lattice\nspacings of 0.093 fm and 0.081 fm. The pion mass of the ensembles is about 260\nMeV. We study excited-states effects by analyzing four values of the\nsource-sink time separation (1.12 - 1.67 fm). We also examine discretization\nand volume effects. The lattice data are renormalized non-perturbatively, and\nthe results are presented in the MS scheme at a scale of 2 GeV.",
        "positive": "Monopole-like configurations in the O(3) spin model at the upper\n  critical dimension: We present a high-precision Monte Carlo study of the O(3) spin theory on the\nlattice in four dimensions. This model exhibits interesting dynamical features,\nin particular in the broken-symmetry phase, where suitable boundary conditions\ncan be used to enforce monopole-like topological excitations. We investigate\nthe Euclidean time propagation and the features of these excitations close to\nthe critical point, where our numerical results show an excellent quantitative\nagreement with analytic predictions derived from purely\nquantum-field-theoretical tools by G. Delfino. We conclude by commenting on the\nimplications of our findings for a conjectured violation of Derrick's theorem\nat the quantum level and on the consequences in various areas of physics,\nranging from condensed matter to astro-particle physics."
    },
    {
        "anchor": "U(1) staggered Dirac operator and random matrix: We investigate the spectrum of the staggered Dirac operator in 4d quenched\nU(1) lattice gauge theory and its relationship to random matrix theory. In the\nconfined as well as in the Coulomb phase the nearest-neighbor spacing\ndistribution of the unfolded eigenvalues is well described by the chiral\nunitary ensemble. The same is true for the distribution of the smallest\neigenvalue and the microscopic spectral density in the confined phase. The\nphysical origin of the chiral condensate in this phase deserves further study.",
        "positive": "Phase structure of a generalized Nambu Jona-Lasinio model with Wilson\n  fermions in the mean field or large $N$-expansion: We analyze the vacuum structure of a generalized lattice Nambu--Jona-Lasinio\nmodel with two flavors of Wilson fermions, such that its continuum action is\nthe most general four-fermion action with 'trivial' color interactions, and\nhaving a $SU(2)_V x SU(2)_A$ symmetry in the chiral limit. The phase structure\nof this model in the space of the two four-fermion couplings shows, in addition\nto the standard Aoki phases, new phases with $<\\bar\\psi \\gamma_5\\psi> != 0$, in\nclose analogy to similar results recently suggested by some of us for lattice\nQCD with two degenerate Wilson fermions. This result shows how the phase\nstructure of an effective model for low energy QCD cannot be entirely\nunderstood from Wilson Chiral Perturbation Theory, based on the standard QCD\nchiral effective Lagrangian approach."
    },
    {
        "anchor": "Temperature-dependence of the QCD topological susceptibility: We recently obtained an estimate of the axion mass based on the hypothesis\nthat axions make up most of the dark matter in the universe. A key ingredient\nfor this calculation was the temperature-dependence of the topological\nsusceptibility of full QCD. Here we summarize the calculation of the\nsusceptibility in a range of temperatures from well below the finite\ntemperature cross-over to around 2 GeV. The two main difficulties of the\ncalculation are the unexpectedly slow convergence of the susceptibility to its\ncontinuum limit and the poor sampling of nonzero topological sectors at high\ntemperature. We discuss how these problems can be solved by two new techniques,\nthe first one with reweighting using the quark zero modes and the second one\nwith the integration method.",
        "positive": "High-precision quark masses and QCD coupling from $n_f=4$ lattice QCD: We present a new lattice QCD analysis of heavy-quark\npseudoscalar-pseudoscalar correlators, using gluon configurations from the MILC\ncollaboration that include vacuum polarization from $u$, $d$, $s$ and\n$c$~quarks($n_f=4$). We extract new values for the QCD coupling and for the $c$\nquark's $\\overline{\\mathrm{MS}}$ mass:\n$\\alpha_{\\overline{\\mathrm{MS}}}(M_Z,n_f=5) = 0.11822(74)$ and\n$m_c(3\\mathrm{GeV}, n_f=4) = 0.9851(63)$GeV. These agree well with our earlier\nsimulations using $n_f=3$ sea quarks, vindicating the perturbative treatment of\n$c$ quarks in that analysis. We also obtain a new nonperturbative result for\nthe ratio of $c$~and $s$~quark masses: $m_c/m_s=11.652(65)$. This ratio implies\n$m_s(2\\,\\mathrm{GeV}, n_f=3)=93.6(8)$MeV when it is combined with our\nnew~$c$~mass. Combining $m_c/m_s$ with our earlier $m_b/m_c$ gives\n$m_b/m_s=52.55(55)$, which is several standard deviations (but only 4%) away\nfrom the Georgi-Jarlskop prediction from certain GUTs. Finally we obtain an\n$n_f=4$ estimate for $m_b/m_c=4.528(54)$ which agrees well with our earlier\n$n_f=3$ result. The new ratio implies~$m_b(m_b,n_f=5)=4.162(48)$GeV."
    },
    {
        "anchor": "Progress Towards finding Quark Masses and the QCD scale Lambda from the\n  Lattice: We discuss recent work trying to extract the renormalised quark masses and\nLambda, the QCD scale, from dynamical simulations in lattice gauge theory.",
        "positive": "Finite-size scaling of heavy-light mesons: We study the finite-size scaling of heavy-light mesons in the static limit.\nThe most relevant effects are due to the pseudo-Goldstone boson cloud. In the\nHMChPT framework we compute two-point functions of left current densitities as\nwell as pseudoscalar densitites for the cases in which some or all of them lay\nin the epsilon-regime. As expected, finite volume dependence turns out to be\nsignificant in this regime and can be predicted in the effective theory in\nterms of the infinite-volume low-energy couplings. These results might be\nrelevant for extraction of heavy-light meson properties from lattice\nsimulations."
    },
    {
        "anchor": "Four quark operators in maximally twisted Wilson LQCD: We discuss how the peculiar properties of maximally twisted Wilson fermions\ncan be exploited to set up a consistent LQCD computational scheme in which the\nCP-conserving matrix elements of the $\\Delta S =1,2$ effective weak Hamiltonian\ncan be evaluated without mixing with wrong-chirality and/or -parity operators.\nThe proposed lattice framework guarantees automatic O($a$) improvement and\npositive determinant also for pairs of non-degenerate quarks.",
        "positive": "Critical slowing down and the gradient flow coupling in the\n  Schr\u00f6dinger functional: We study the sensitivity of the gradient flow coupling to sectors of\ndifferent topological charge and its implications in practical situations.\nFurthermore, we investigate an alternative definition of the running coupling\nthat is expected to be less sensitive to the problems of the HMC algorithm to\nefficiently sample all topological sectors."
    },
    {
        "anchor": "Center Disorder in the 3D Georgi-Glashow Model: We present a number of arguments relating magnetic disorder to center\ndisorder, in pure Yang-Mills theory in D=3 and D=4 dimensions. In the case of\nthe D=3 Georgi-Glashow model, we point out that the abelian field distribution\nis not adequatedly represented, at very large scales, by that of a monopole\nCoulomb gas. The onset of center disorder is associated with the breakdown of\nthe Coulomb gas approximation; this scale is pushed off to infinity in the\nQED_3 limit of the 3D Georgi-Glashow model, but should approach the\ncolor-screening length in the pure Yang-Mills limit.",
        "positive": "Coulomb gauge gluon propagator and the Gribov formula: We analyze the lattice SU(2) Yang-Mills theory in Coulomb gauge. We show that\nthe static gluon propagator is multiplicative renormalizable and takes the\nsimple form $D(|\\vec{p}|)^{-1}=\\sqrt{|\\vec{p}|^2+M^4/|\\vec{p}|^2}$, proposed by\nGribov through heuristic arguments many years ago. We find $M=0.88(1) {\\rm GeV}\n\\simeq 2 \\sqrt{\\sigma}$."
    },
    {
        "anchor": "The heavy quark potential in QCD with 2 flavors of dynamical quarks: We compute the heavy quark potential on configurations generated by the\nHEMCGC collaboration with dynamical staggered fermions at $6/g^2 = 5.6$ and\nwith dynamical Wilson fermions at $6/g^2 = 5.3$. The computations are done on\n$16^3 \\times 32$ lattices, corresponding to physical sizes of about 1.6 and 2.3\nfm, respectively. Up to the distances probed no sign of string breaking is\ndetectable. We also compute the recently proposed scale $r_0$ defined by $r_0^2\nF(r_0) = 1.65$.",
        "positive": "Yang-Mills streamlines and semi-classical confinement: Semi-classical configurations in Yang-Mills theory have been derived from\nlattice Monte Carlo configurations using a recently proposed constrained\ncooling technique which is designed to preserve every Polyakov line (at any\npoint in space-time in any direction). Consequently, confinement was found\nsustained by the ensemble of semi-classical configurations. The existence of\ngluonic and fermionic near-to-zero modes was demonstrated as a precondition for\na possible semi-classical expansion around the cooled configurations as well as\nproviding the gapless spectrum of the Dirac operator necessary for chiral\nsymmetry breaking. The cluster structure of topological charge of the\nsemi-classical streamline configurations was analysed and shown to support the\naxial anomaly of the right size, although the structure differs from the\ninstanton gas or liquid. Here, we present further details on the space-time\nstructure and the time evolution of the streamline configurations."
    },
    {
        "anchor": "Spin 3/2 Pentaquark Resonance Signature in Lattice QCD: The possible discovery of the Theta+ pentaquark has motivated a number of\nstudies of its nature using lattice QCD. While all the analyses thus far have\nfocussed on spin-1/2 states, here we report the results of the first\nexploratory study in quenched lattice QCD of pentaquarks with spin 3/2. For the\nspin-3/2 interpolating field we use a product of the standard N and K*\noperators. We do not find any evidence for the standard lattice resonance\nsignature of attraction (i.e., binding at quark masses near the physical\nregime) in the J^P = 3/2- channel. Some evidence of binding is inferred in the\nisoscalar 3/2+ channel at several quark masses, in accord with the standard\nlattice resonance signature. This suggests that this is a good candidate for\nthe further study of pentaquarks on the lattice.",
        "positive": "Lattice QCD-2+1: We consider a 2+1-dimensional SU(N) lattice gauge theory in an axial gauge\nwith the link field U in the 1-direction set to one. The term in the\nHamiltonian containing the square of the electric field in the 1-direction is\nnon-local. Despite this non-locality, we show that weak-coupling perturbation\ntheory in this term gives a finite vacuum-energy density to second order, and\nsuggest that this property holds to all orders. Heavy quarks are confined, the\nspectrum is gapped, and the space-like Wilson loop has area decay."
    },
    {
        "anchor": "Localization and chiral symmetry in 2+1 flavor domain wall QCD: We present results for the dependence of the residual mass of domain wall\nfermions (DWF) on the size of the fifth dimension and its relation to the\ndensity and localization properties of low-lying eigenvectors of the\ncorresponding hermitian Wilson Dirac operator relevant to simulations of 2+1\nflavor domain wall QCD. Using the DBW2 and Iwasaki gauge actions, we generate\nensembles of configurations with a $16^3\\times 32$ space-time volume and an\nextent of 8 in the fifth dimension for the sea quarks. We demonstrate the\nexistence of a regime where the degree of locality, the size of chiral symmetry\nbreaking and the rate of topology change can be acceptable for inverse lattice\nspacings $a^{-1} \\ge 1.6$ GeV.",
        "positive": "One-loop anisotropy for improved actions: We determine the one-loop correction to the anisotropy factor for the square\nSymanzik improved lattice action, extracted fromthe finite volume effective\naction for SU(N) gauge theories in the background of a zero-momentum gauge\nfield. The result is smaller by approximately a factor 3 than the one-loop\ncorrection for the anisotropic Wilson action. We also comment on the\nHamiltonian limit."
    },
    {
        "anchor": "On the equivalence between 2D Yukawa and Gross-Neveu models: We study numerically on the lattice the 2D Yukawa model with the U(1) chiral\nsymmetry and $N_F$ = 16 at infinite scalar field self-coupling. The scaling\nbehaviour of the fermion mass, as the Yukawa coupling approaches zero, is\nanalysed using the mean field method. It is found to agree with that of the\nGross-Neveu model with the same symmetry and $N_F$. The results suggest that\nthe 2D Yukawa models belong to the universality class of the Gross-Neveu models\nnot only at weak scalar field self-coupling but also for a broad range of the\nbare parameters which is not accessible to the $1/N_F$ expansion. New\nuniversality classes might arise at the crossover to the spin model\nuniversality class, however.",
        "positive": "$\u039b\u039b$ and N$\u039e$ interactions from Lattice QCD near the\n  physical point: The $S$-wave $\\Lambda\\Lambda$ and $N \\Xi$ interactions are studied on the\nbasis of the (2+1)-flavor lattice QCD simulations close to the physical point\n($m_\\pi \\simeq 146{\\rm{MeV}}$ and $m_K \\simeq 525{\\rm{MeV}}$). Lattice QCD\npotentials in four different spin-isospin channels are extracted by using the\ncoupled-channel HAL QCD method and are parametrized by analytic functions to\ncalculate the scattering phase shifts. The $\\Lambda \\Lambda$ interaction at low\nenergies shows only a weak attraction, which does not provide a bound or\nresonant dihyperon. The $N\\Xi$ interaction in the spin-singlet and\nisospin-singlet channel is most attractive and lead the $N\\Xi$ system near\nunitarity. Relevance to the strangeness=$-2$ hypernuclei as well as to\ntwo-baryon correlations in proton-proton, proton-nucleus and nucleus-nucleus\ncollisions is also discussed."
    },
    {
        "anchor": "A Method for Measuring the Witten Index Using Lattice Simulation: We propose a method to measure the Witten index using lattice simulation. A\nrequirement for the lattice model is that it has at least one exact\nsupersymmetry at finite lattice spacing. We prove the validity of the method in\ncase of the supersymmetric quantum mechanics, where the index is well known.",
        "positive": "Optimizing the Chiral Properties of Lattice Fermion Actions: We describe a way to optimize the chiral behavior of Wilson-type lattice\nfermion actions by studying the low energy real eigenmodes of the Dirac\noperator. We find a candidate action, the clover action with fat links with a\ntuned clover term. We present a calculation of spectroscopy and matrix elements\nat Wilson gauge coupling $\\beta=5.7$. The action shows good scaling behavior."
    },
    {
        "anchor": "Flux simulation of the SU(3) spin model at finite chemical potential: We present a Monte Carlo simulation of an effective theory for local Polyakov\nloops at finite temperature and density. The sign problem is overcome by\nmapping the partition sum to a flux representation. We determine the phase\ndiagram of the model as a function of the temperature and the chemical\npotential.",
        "positive": "Bottomonium resonances from lattice QCD static-static-light-light\n  potentials: We study $I=0$ quarkonium resonances decaying into pairs of heavy-light\nmesons using static-static-light-light potentials from lattice QCD. To this\nend, we solve a coupled channel Schr\\\"odinger equation with a confined\nquarkonium channel and channels with a heavy-light meson pair to compute phase\nshifts and $\\mbox{T}$ matrix poles for the lightest decay channel. We discuss\nour results for $S$, $P$, $D$ and $F$ wave states in the context of\ncorresponding experimental results, in particular for $\\Upsilon(10753)$ and\n$\\Upsilon(10860)$."
    },
    {
        "anchor": "Qubit Regularization and Qubit Embedding Algebras: Qubit regularization is a procedure to regularize the infinite dimensional\nlocal Hilbert space of bosonic fields to a finite dimensional one, which is a\ncrucial step when trying to simulate lattice quantum field theories on a\nquantum computer. When the qubit-regularized lattice quantum fields preserve\nimportant symmetries of the original theory, qubit regularization naturally\nenforces certain algebraic structures on these quantum fields. We introduce the\nconcept of qubit embedding algebras (QEAs) to characterize this algebraic\nstructure associated with a qubit regularization scheme. We show a systematic\nprocedure to derive QEAs for the O(N) lattice spin models and the SU(N) lattice\ngauge theories. While some of the QEAs we find were discovered earlier in the\ncontext of the D-theory approach, our method shows that QEAs are far more\nricher. A more complete understanding of the QEAs could be helpful in\nrecovering the fixed points of the desired quantum field theories.",
        "positive": "Lattice calculation of the R-ratio smeared with Gaussian kernel: The ratio $R(E)$ of the cross-sections for $e^+e^-\\to$ hadrons and $e^+e^-\\to\n\\mu^+\\mu^-$ is a valuable energy-dependent probe of the hadronic sector of the\nStandard Model. Moreover, the experimental measurements of $R(E)$ are the\ninputs of the dispersive calculations of the leading hadronic vacuum\npolarization contribution to the muon $g-2$ and these are in significant\ntension with direct lattice calculations and with the muon $g-2$ experiment. In\nthis talk we discuss the results of our first-principles lattice study of\n$R(E)$. By using a recently proposed method for extracting smeared spectral\ndensities from Euclidean lattice correlators, we have calculated $R(E)$\nconvoluted with Gaussian kernels of different widths $\\sigma$ and central\nenergies up to $2.5$ GeV. Our theoretical results have been compared with the\nKNT19 [1] compilation of experimental results smeared with the same Gaussian\nkernels and a tension (about three standard deviations) has been observed for\n$\\sigma\\sim 600$ MeV and central energies around the $\\rho$-resonance peak."
    },
    {
        "anchor": "Phase Diagram of An SU(2)xSU(2) Scalar-Fermion Model with Massless\n  Decoupled Doublers: We present the phase structure of the chiral SU(2)xSU(2) scalar-fermion model\non the lattice using the Zaragoza proposal for chiral fermions. The numerical\nresult agrees with an analytic study based on the use of weak and strong Yukawa\ncoupling expansions combined with the mean field approach. The phase diagram\nconsits of four phases: paramagnetic(PM), ferromagnetic(FM),\nantiferromagnetic(AFM) and ferrimagnetic (FI). The transition lines separating\nthese four phases intersect at one quadruple point.",
        "positive": "Monopole clusters, center vortices, and confinement in a Z(2)\n  gauge-Higgs system: We propose to use the different kinds of vacua of the gauge theories coupled\nto matter as a laboratory to test confinement ideas of pure Yang-Mills\ntheories. In particular, the very poor overlap of the Wilson loop with the\nbroken string states supports the 't Hooft and Mandelstam confinement criteria.\nHowever in the Z(2) gauge-Higgs model we use as a guide we find that the\ncondensation of monopoles and center vortices is a necessary, but not\nsufficient condition for confinement."
    },
    {
        "anchor": "Tricritical points in a compact $U(1)$ lattice gauge theory at strong\n  coupling: Pure {\\it compact} $U(1)$ lattice gauge theory exhibits a phase transition at\ngauge coupling $g \\sim {\\cal{O}}(1)$ separating a familiar weak coupling\nCoulomb phase, having free massless photons, from a strong coupling phase.\nHowever, the phase transition was found to be of first order, ruling out any\nnontrivial theory resulting from a continuum limit from the strong coupling\nside. In this work, a compact $U(1)$ lattice gauge theory is studied with\naddition of a dimension-two mass counterterm and a higher derivative (HD) term\nthat ensures a unique vacuum and produces a covariant gauge-fixing term in the\nnaive continuum limit. For a reasonably large coefficient of the HD term, now\nthere exists a continuous transition from a regular ordered phase to a\nspatially modulated ordered phase. For weak gauge couplings, a continuum limit\nfrom the regular ordered phase results in a familiar theory consisting of free\nmassless photons. For strong gauge couplings with $g\\ge {\\cal{O}}(1)$, this\ntransition changes from first order to continuous as the coefficient of the HD\nterm is increased, resulting in tricritical points which appear to be a\ncandidate in this theory for a possible nontrivial continuum limit.",
        "positive": "Hadronic light-by-light contribution to the muon anomalous magnetic\n  moment from lattice QCD: We report preliminary results for the hadronic light-by-light scattering\ncontribution to the muon anomalous magnetic moment. Several ensembles using 2+1\nflavors of M\\\"obius domain-wall fermions, generated by the RBC/UKQCD\ncollaborations, are employed to take the continuum and infinite volume limits\nof finite volume lattice QED+QCD. We find $a_\\mu^{\\rm HLbL} =\n(7.41\\pm6.33)\\times 10^{-10}$"
    },
    {
        "anchor": "Is there still any Tc mystery in lattice QCD? Results with physical\n  masses in the continuum limit III: The present paper concludes our investigations on the QCD cross-over\ntransition temperatures with 2+1 staggered flavours and one-link stout\nimprovement. We extend our previous two studies [Phys. Lett. B643 (2006) 46,\nJHEP 0906:088 (2009)] by choosing even finer lattices ($N_t$=16) and we work\nagain with physical quark masses. The new results on this broad cross-over are\nin complete agreement with our earlier ones. We compare our findings with the\npublished results of the hotQCD collaboration. All these results are confronted\nwith the predictions of the Hadron Resonance Gas model and Chiral Perturbation\nTheory for temperatures below the transition region. Our results can be\nreproduced by using the physical spectrum in these analytic calculations. The\nfindings of the hotQCD collaboration can be recovered by using a distorted\nspectrum which takes into account lattice discretization artifacts and heavier\nthan physical quark masses. This analysis provides a simple explanation for the\nobserved discrepancy in the transition temperatures between our and the hotQCD\ncollaborations.",
        "positive": "The QCD Deconfinement Critical Point for $N_\\text{f}=2$ Flavors of\n  Staggered Fermions: Quenched QCD at zero baryonic chemical potential undergoes a first-order\ndeconfinement phase transition at a critical temperature $T_c$, which is\nrelated to the spontaneous breaking of the global center symmetry. Including\nheavy, dynamical quarks breaks the center symmetry explicitly and weakens the\nfirst-order phase transition. For decreasing quark masses the first-order phase\ntransition turns into a smooth crossover at a $Z_2$-critical point. The\ncritical quark mass corresponding to this point has been examined with\n$N_\\text{f} = 2$ Wilson fermions for several $N_\\tau$ in a recent study within\nour group. For comparison, we also locate the critical point with $N_\\text{f} =\n2$ staggered fermions on $N_\\tau = 8$ lattices. For this purpose we perform\nMonte Carlo simulations for several quark mass values and various aspect ratios\nin order to extrapolate to the thermodynamic limit. The critical mass is\nobtained by fitting to a finite size scaling formula of the kurtosis of the\nPolyakov loop. Our results indicate large discretization effects, requiring\nsimulations on lattices with $N_\\tau > 8$."
    },
    {
        "anchor": "Application of Domain Decomposition to the Evaluation of Fermion\n  Determinant Ratios: We analyze the fluctuations in the case of mass reweighting for N_f=2 Wilson\nfermions. We use a domain decomposition factorization of the fermion\ndeterminant. Ratios of determinants are estimated stochastically. We study the\nstochastic and the ensemble fluctuations as a function of the volume V and the\nmass shift Delta m. With our result it is possible to estimate the cost and the\neffectiveness of mass reweighting. In addition we introduce a stochastic\nestimation for the one flavor case without using the square root.",
        "positive": "Stochastic reconstructions of spectral functions: Application to lattice\n  QCD: We present a detailed study of the applications of two stochastic approaches,\nstochastic optimization method (SOM) and stochastic analytical inference (SAI),\nto extract spectral functions from Euclidean correlation functions. SOM has the\nadvantage that it does not require prior information. On the other hand, SAI is\na more generalized method based on Bayesian inference. Under mean field\napproximation SAI reduces to the often-used maximum entropy method (MEM), and\nfor a specific choice of the prior SAI becomes equivalent to SOM. To test the\napplicability of these two stochastic methods to lattice QCD, firstly, we apply\nthese methods to various reasonably chosen model correlation functions, and\npresent detailed comparisons of the reconstructed spectral functions obtained\nfrom SOM, SAI and MEM. Next, we present similar studies for charmonia\ncorrelation functions obtained from lattice QCD computations using\nclover-improved Wilson fermions on large, fine, isotropic lattices at $0.75$\nand $1.5T_c$, $T_c$ being the deconfinement transition temperature of a pure\ngluon plasma. We find that SAI and SOM give consistent results to MEM at these\ntwo temperatures."
    },
    {
        "anchor": "EOS in 2+1 flavor QCD with improved Wilson quarks by the fixed-scale\n  approach: We present the status of our study on the equation of state in 2+1 flavor QCD\nwith non-perturbatively improved Wilson quarks coupled with the RG improved\nglue. We apply the T-integration method to non-perturbatively calculate the\nequation of state by the fixed-scale approach.",
        "positive": "Hodge gauge fixing in three dimensions: A progress report on experiences with a gauge fixing method proposed in\nLATTICE 94 is presented. In this algorithm, an SU(N) operator is diagonalized\nat each site, followed by gauge fixing the diagonal (Cartan) part of the links\nto Coulomb gauge using the residual abelian freedom. The Cartan sector of the\nlink field is separated into the physical gauge field $\\alpha^{(f)}_\\mu$\nresponsible for producing $f^{\\rm Cartan}_{\\mu\\nu}$, the pure gauge part,\nlattice artifacts, and zero modes. The gauge transformation to the physical\ngauge field $\\alpha^{(f)}_\\mu$ is then constructed and performed. Compactness\nof the lattice fields entails issues related to monopoles and zero modes which\nare addressed."
    },
    {
        "anchor": "Study of the order of the phase transition in pure U(1) gauge theory\n  with Villain action: We address the question of the order of the deconfinement phase transition of\nfour dimensional U(1) lattice gauge theory. Simulations of the Z-gauge theory\ndual to the Villain action on toroidal lattices up to lattice sizes of 28^4\ngive results consistent with both, a vanishing and a nonvanishing discontinuity\nin the thermodynamic limit. A decision on the order of the phase transition\nrequires still larger lattice sizes.",
        "positive": "Lattice Gauge Theory for a Quantum Computer: The quantum link~\\cite{Brower:1997ha} Hamiltonian was introduced two decades\nago as an alternative to Wilson's Euclidean lattice QCD with gauge fields\nrepresented by bi-linear fermion/anti-fermion operators. When generalized this\nnew microscopic representation of lattice field theories is referred as {\\tt\nD-theory}~\\cite{Brower:2003vy}. Recast as a Hamiltonian in Minkowski space for\nreal time evolution, D-theory leads naturally to quantum Qubit algorithms. Here\nto explore digital quantum computing for gauge theories, the simplest example\nof U(1) compact QED on triangular lattice is defined and gauge invariant\nkernels for the Suzuki-Trotter expansions are expressed as Qubit circuits\ncapable of being tested on the IBM-Q and other existing Noisy Intermediate\nScale Quantum (NISQ) hardware. This is a modest step in exploring the quantum\ncomplexity of D-theory to guide future applications to high energy physics and\ncondensed matter quantum field theories."
    },
    {
        "anchor": "On the behaviour of the interquark potential in the vicinity of the\n  deconfinement transition: In the vicinity of the deconfinement transition the behaviour of the\ninterquark potential can be precisely predicted using the Effective String\nTheory (EST). If the transition is continuous we can combine EST results with a\nconformal perturbation analysis and reach the degree of precision needed to\ndetect the corrections beyond the Nambu-Goto approximation in the EST. We\ndiscuss in detail this issue in the case of the deconfinement transition of the\nSU(2) gauge theory in $(2+1)$ dimensions (which belongs to the same\nuniversality class of the 2d Ising model) by means of an extensive set of high\nprecision simulations. We show that the Polyakov loops correlator of the SU(2)\nmodel is precisely described by the spin-spin correlator of the 2d Ising model\nnot only at the critical point, but also down to temperatures of the order of\n$0.8 T_c$. Thanks to the exact integrability of the Ising model we can extend\nthe comparison in the whole range of Polyakov loop separations, even beyond the\nconformal perturbation regime. We use these results to quantify the first EST\ncorrection beyond Nambu-Goto and show that it is compatible with the bounds\nimposed by a bootstrap analysis of EST. This correction encodes important\nphysical information and may shed light on the nature of the flux tube and of\nits EST description.",
        "positive": "Chiral symmetry at finite T, the phase of the Polyakov loop and the\n  spectrum of the Dirac operator: A recent Monte Carlo study of {\\em quenched} QCD showed that the chiral\ncondensate is non-vanishing above $T_c$ in the phase where the average of the\nPolyakov loop $P$ is complex. We show how this is related to the dependence of\nthe spectrum of the Dirac operator on the boundary conditions in Euclidean\ntime. We use a random matrix model to calculate the density of small\neigenvalues and the chiral condensate as a function of $\\arg P$. The chiral\nsymmetry is restored in the $\\arg P=2\\pi/3$ phase at a higher $T$ than in the\n$\\arg P=0$ phase. In the phase $\\arg P = \\pi$ of the $SU(2)$ gauge theory the\nchiral condensate stays nonzero for all~$T$."
    },
    {
        "anchor": "Effective string description of the confining flux tube at finite\n  temperature: In this review, after a general introduction to the effective string theory\n(EST) description of confinement in pure gauge theories, we discuss the\nbehaviour of EST as the temperature is increased. We show that, as the\ndeconfinement point is approached from below, several universal features of\nconfining gauge theories, like the ratio $T_c/\\sqrt{\\sigma_0}$, the linear\nincrease of the squared width of the flux tube with the interquark distance, or\nthe Temperature dependence of the interquark potential, can be accurately\npredicted by the effective string. Moreover in the vicinity of the\ndeconfinement point the EST behaviour turns out to be in good agreement with\nwhat predicted by conformal invariance or by dimensional reduction, thus\nfurther supporting the validity of and EST approach to confinement.",
        "positive": "Exotic hybrid mesons from improved Kogut-Susskind fermions: We summarize our measurement of the mass of the exotic $1^{-+}$ hybrid meson\nusing an improved Kogut-Susskind action. We show results from both quenched and\ndynamical quark simulations and compare with results from Wilson quarks.\nExtrapolation of these results to the physical quark mass allows comparison\nwith experimental candidates for the $1^{-+}$ hybrid meson."
    },
    {
        "anchor": "Correlations for non-Hermitian Dirac operators: chemical potential in\n  three-dimensional QCD: In the presence of a non-vanishing chemical potential the eigenvalues of the\nDirac operator become complex. We use a random matrix model approach to\ncalculate analytically all correlation functions at weak and strong\nnon-Hermiticity for three-dimensional QCD with broken flavor symmetry and\nfour-dimensional QCD in the bulk.",
        "positive": "Light dynamical fermions on the lattice: toward the chiral regime of QCD: Algorithmic and technical progress achieved over the last few years makes QCD\nsimulations with light dynamical quarks much faster than before. As a result\nlattices with pions as light as 250--300 MeV can be simulated with the present\ngeneration of computers. I review recent conceptual and numerical progress in\nthis field, with particular emphasis on results obtained and difficulties\nencountered in simulations with significantly smaller quark masses with respect\nto previous computations. I also attempt to compare physical results for pion\nmasses and decay constants available to date in the two-flavour theory with\nexpectations from chiral perturbation theory."
    },
    {
        "anchor": "Improving perturbation theory with cactus diagrams: We study a systematic improvement of perturbation theory for gauge fields on\nthe lattice [hep-lat/0606001]; the improvement entails resumming, to all orders\nin the coupling constant, a dominant subclass of tadpole diagrams.\n  This method, originally proposed for the Wilson gluon action, is extended\nhere to encompass all possible gluon actions made of closed Wilson loops; any\nfermion action can be employed as well. The effect of resummation is to replace\nvarious parameters in the action (coupling constant, Symanzik and clover\ncoefficient) by ``dressed'' values; the latter are solutions to certain coupled\nintegral equations, which are easy to solve numerically.\n  Some positive features of this method are: a) It is gauge invariant, b) it\ncan be systematically applied to improve (to all orders) results obtained at\nany given order in perturbation theory, c) it does indeed absorb in the dressed\nparameters the bulk of tadpole contributions.\n  Two different applications are presented: The additive renormalization of\nfermion masses, and the multiplicative renormalization Z_V (Z_A) of the vector\n(axial) current. In many cases where non-perturbative estimates of\nrenormalization functions are also available for comparison, the agreement with\nimproved perturbative results is consistently better as compared to results\nfrom bare perturbation theory.",
        "positive": "High Statistics Analysis using Anisotropic Clover Lattices: (IV) Volume\n  Dependence of Light Hadron Masses: The volume dependence of the octet baryon masses and relations among them are\nexplored with Lattice QCD. Calculations are performed with n_f=2+1 clover\nfermion discretization in four lattice volumes, with spatial extent L ~ 2.0,\n2.5, 3.0 and 3.9 fm, with an anisotropic lattice spacing of b_s ~ 0.123 fm in\nthe spatial direction, and b_t = b_s/3.5 in the time direction, and at a pion\nmass of m_pi ~ 390 MeV. The typical precision of the ground-state baryon mass\ndetermination is ~0.2%, enabling a precise exploration of the volume dependence\nof the masses, the Gell-Mann--Okubo mass relation, and of other mass\ncombinations. A comparison of the volume dependence with the predictions of\nheavy baryon chiral perturbation theory is performed in both the SU(2)_L X\nSU(2)_R and SU(3)_L X SU(3)_R expansions. Predictions of the three-flavor\nexpansion for the hadron masses are found to describe the observed volume\ndependences reasonably well. Further, the Delta-N-pi axial coupling constant is\nextracted from the volume dependence of the nucleon mass in the two-flavor\nexpansion, with only small modifications in the three-flavor expansion from the\ninclusion of kaons and etas. At a given value of m_pi L, the finite-volume\ncontributions to the nucleon mass are predicted to be significantly smaller at\nm_pi ~ 140 MeV than at m_pi ~ 390 MeV due to a coefficient that scales as ~\nm_pi^3. This is relevant for the design of future ensembles of lattice\ngauge-field configurations. Finally, the volume dependence of the pion and kaon\nmasses are analyzed with two-flavor and three-flavor chiral perturbation\ntheory."
    },
    {
        "anchor": "QCD phase transition at real chemical potential with canonical approach: We study the finite density phase transition in the lattice QCD at real\nchemical potential. We adopt canonical approach and the canonical partition\nfunction is constructed for Nf=2 QCD. After derivation of the canonical\npartition function we calculate observables like the pressure, the quark number\ndensity, its second cumulant and the chiral condensate as a function of the\nreal chemical potential. We covered a wide range of temperature region starting\nfrom the confining low to the deconfining high temperature. We observe signals\nfor the deconfinement and the chiral restoration phase transition at real\nchemical potential below Tc starting from the confining phase.",
        "positive": "Anomalous transport phenomena on the lattice: The interrelation between quantum anomalies and electromagnetic fields leads\nto a series of non-dissipative transport effects in QCD. In this work we study\nanomalous transport phenomena with lattice QCD simulations using improved\nstaggered quarks in the presence of a background magnetic field. In particular,\nwe calculate the conductivities both in the free case and in the interacting\ncase, analysing the dependence of these coefficients with several parameters,\nsuch as the temperature and the quark mass."
    },
    {
        "anchor": "Bottomonium Decay Matrix Elements from Lattice QCD with Two Light Quarks: We calculate the long-distance matrix elements for the decays of the Upsilon\n(eta_b) and chi_b (h_b) states in lattice QCD with two flavors of light\ndynamical quarks. We relate the lattice matrix elements to their continuum\ncounterparts through one-loop order in perturbation theory. In the case of the\nleading S-wave matrix element, we compare our result with a phenomenological\nvalue that we extract from the experimental leptonic decay rate by using the\ntheoretical expression for the decay rate, accurate through relative order\nalpha_s. Whereas estimates of the leading S-wave matrix element from quenched\nQCD are 40--45% lower than the phenomenological value, the two-flavor estimate\nof the same matrix element is close to the phenomenological value.\nExtrapolating to the real world of 2+1 light flavors, we find that this matrix\nelement is approximately 6% higher than the phenomenological value, but that\nthe phenomenological value lies within our error bars. We also compute the\ncolor-singlet and color-octet matrix elements for P-wave decays. We find the\nvalue of the color-singlet matrix element for 2+1 flavors to be approximately\n70% larger than the quenched value and the value of the color-octet matrix\nelement for 2+1 flavors to be approximately 40% larger than the quenched value.",
        "positive": "The QCD vacuum probed by overlap fermions: We summarize different uses of the eigenmodes of the Neuberger overlap\noperator for the analysis of the QCD vacuum, here applied to quenched\nconfigurations simulated by means of the Luescher-Weisz action. We describe the\nlocalization and chiral properties of the lowest modes. The overlap-based\ntopological charge density (with and without UV-filtering) is compared with the\nresults of UV-filtering for the field strength tensor. The latter allows to\nidentify domains of good (anti-)selfduality. All these techniques together lead\nto a dual picture of the vacuum, unifying the infrared instanton picture with\nthe presence of singular defects co-existent at different scales."
    },
    {
        "anchor": "Finite-volume matrix elements in multi-boson states: We derive the relations necessary for the extraction of matrix elements of\nmulti-hadron systems from finite-volume QCD calculations. We focus on systems\nof $n \\ge 2$ weakly interacting identical particles without spin. These results\nwill be useful in extracting physical quantities from lattice QCD measurements\nof such matrix elements in many-pion and many-kaon systems",
        "positive": "Testing new strategies in finite density: A new approach for non zero chemical potential simulations is tested in the\nGross-Neveu model for infinite flavor number, where the critical line is\nreconstructed in a large $\\mu/T$ interval. A comparison with results from\nstandard imaginary chemical potential approach as well as first results for\n$N_f=4$ QCD are presented."
    },
    {
        "anchor": "Two dimensional SU(N)xSU(N) Chiral Models on the Lattice (II): the\n  Green's Function: Analytical and numerical methods are applied to principal chiral models on a\ntwo-dimensional lattice and their predictions are tested and compared. New\ntechniques for the strong coupling expansion of SU(N) models are developed and\napplied to the evaluation of the two-point correlation function. The\nmomentum-space lattice propagator is constructed with precision O(\\beta^{10})\nand an evaluation of the correlation length is obtained for several different\ndefinitions. Three-loop weak coupling contributions to the internal energy and\nto the lattice $\\beta$ and $\\gamma$ functions are evaluated for all N, and the\neffect of adopting the ``energy'' definition of temperature is computed with\nthe same precision. Renormalization-group improved predictions for the\ntwo-point Green's function in the weak coupling ( continuum ) regime are\nobtained and successfully compared with Monte Carlo data. We find that strong\ncoupling is predictive up to a point where asymptotic scaling in the energy\nscheme is observed. Continuum physics is insensitive to the effects of the\nlarge N phase transition occurring in the lattice model. Universality in N is\nalready well established for $N \\ge 10$ and the large N physics is well\ndescribed by a ``hadronization'' picture.",
        "positive": "Platform independent profiling of a QCD code: The supercomputing platforms available for high performance computing based\nresearch evolve at a great rate. However, this rapid development of novel\ntechnologies requires constant adaptations and optimizations of the existing\ncodes for each new machine architecture. In such context, minimizing time of\nefficiently porting the code on a new platform is of crucial importance. A\npossible solution for this common challenge is to use simulations of the\napplication that can assist in detecting performance bottlenecks. Due to\nprohibitive costs of classical cycle-accurate simulators, coarse-grain\nsimulations are more suitable for large parallel and distributed systems. We\npresent a procedure of implementing the profiling for openQCD code [1] through\nsimulation, which will enable the global reduction of the cost of profiling and\noptimizing this code commonly used in the lattice QCD community. Our approach\nis based on well-known SimGrid simulator [2], which allows for fast and\naccurate performance predictions of HPC codes. Additionally, accurate\nestimations of the program behavior on some future machines, not yet accessible\nto us, are anticipated."
    },
    {
        "anchor": "Crossover scaling from classical to non-classical critical behaviour: Interacting physical systems in the neighborhood of criticality (and massive\ncontinuum field theories) can often be characterized by just two physical\nscales: a (macroscopic) correlation length and a (microscopic) interaction\nrange, related to the coupling and measured by the Ginzburg number $G$. A\ncritical crossover limit can be defined when both scales become large while\ntheir ratio stays finite. The corresponding scaling functions are universal,\nand they are related to the standard field-theory renormalization-group\nfunctions. The critical crossover describes the unique flow from the Gaussian\nto the nonclassical fixed point.",
        "positive": "Excited state contamination in nucleon structure calculations: Among the sources of systematic error in nucleon structure calculations is\ncontamination from unwanted excited states. In order to measure this systematic\nerror, we vary the operator insertion time and source-sink separation\nindependently. We compute observables for three source-sink separations between\n0.93 fm and 1.39 fm using clover-improved Wilson fermions and pion masses as\nlow as 150 MeV. We explore the use of a two-state model fit to subtract off the\ncontribution from excited states."
    },
    {
        "anchor": "Z(2)-symmetric center vortex model with a first-order deconfinement\n  transition: A random vortex world-surface model for the infrared sector of Sp(2)\nYang-Mills theory is constructed. The Sp(2) gauge group, while allowing for the\nsame set of center vortex fluxes as the SU(2) gauge group, induces a\nsignificantly different dynamics on those vortex fluxes, which manifests itself\nin a first-order deconfinement phase transition. As shown by the construction\npresented here, a new vortex effective action term which can be interpreted in\nterms of a vortex stickiness can be used to drive the deconfinement transition\ntowards first-order behavior. The available data from lattice Sp(2) Yang-Mills\ntheory are reproduced quantitatively and, in addition, predictions for the\nbehavior of the spatial string tension at high temperatures are presented.",
        "positive": "On the spectrum of QCD-like theories and the conformal window: We report on the spectrum of the SU(3) gauge theory with twelve flavours in\nthe fundamental representation of the gauge group. We isolate distinctive\nfeatures of the hadronic phase - the one proper of QCD at zero temperature -\nand the so called conformal phase. The latter should emerge at sufficiently\nlarge Nf and before the loss of asymptotic freedom. In particular, we analyse\navailable lattice data for the spectrum of Nf=12 and include a comparison with\nresults with Nf=16; the latter theory, predicted by the perturbative\nbeta-function to develop an IRFP and therefore be in the conformal phase, can\nserve as a paradigm for the study of theories in the conformal window. Our\nanalysis suggests that the theory with twelve flavours is in the conformal\nwindow, possibly close to its lower boundary."
    },
    {
        "anchor": "Finite temperature QCD: progress and outstanding problems: I review recent progress in numerical simulations of finite temperature\nquantum chromodynamics and discuss the status of some outstanding problems.\nIncluded is (1) a discussion of recent results determining the temperature of\nthe ``phase transition'' in full QCD, (2) a scaling analysis of the Polyakov\nloop variable, leading to the determination of a constituent quark free energy,\n(3) studies of critical behavior near the phase transition in two-flavor QCD,\n(4) a discussion of problems and new results in thermodynamic simulations with\nWilson fermions, (5) recent results in pure gauge theory with a mixed\nfundamental/adjoint action, and (6) the nonperturbative determination of the\nequation of state with dynamical fermions included. Finally I mention briefly\nnew developments in efforts to construct a phenomenology of deconfinement and\nchiral symmetry restoration, namely (7) the dual superconducting model and (8)\nthe instanton model.",
        "positive": "IR suppression of the Coulomb gauge gluon propagator in SU(3) Yang-Mills\n  theory: We calculate the equal-time transverse gluon propagator in Coulomb gauge QCD\nusing a SU(3) quenched lattice gauge simulation on large lattices, up to 11\n[fm$^4$]. We find that the equal-time gluon propagator shows scaling violation;\nnamely, the data for different lattice spacings do not fall on top of one\ncurve. This problem is cured by discarding data at large momenta, which suffer\nfrom discretization errors. In the infrared region, the transverse gluon\npropagator is strongly suppressed and shows a turnover at about 500 [MeV].\nFitting the power law ansatz to the data at small momenta predicts the\nvanishing gluon propagator at zero momentum, indicating the confinement of\ngluons."
    },
    {
        "anchor": "Nearly conformal electroweak sector with chiral fermions: SU(3) gauge theory with dynamical overlap fermions in the 2-index symmetric\n(sextet) representation is considered. This model may be a viable model of the\nelectroweak symmetry breaking sector along the lines of the walking technicolor\nparadigm. The number of fermion species is chosen such that the theory is\nexpected to be below the conformal window. We will discuss how the\nepsilon-regime and random matrix theory can be used to test whether at any\ngiven set of parameters (N_c, N_f, representation) the theory is in the\nconformal phase or indeed just below it. Quenched Monte Carlo results are\nincluded in the fundamental representation and also preliminary dynamical ones\nin the 2-index symmetric representation.",
        "positive": "Alternative to Domain Wall Fermions: An alternative to commonly used domain wall fermions is presented. Some\nrigorous bounds on the condition number of the associated linear problem are\nderived. On the basis of these bounds and some experimentation it is argued\nthat domain wall fermions will in general be associated with a condition number\nthat is of the same order of magnitude as the {\\it product} of the condition\nnumber of the linear problem in the physical dimensions by the inverse bare\nquark mass. Thus, the computational cost of implementing true domain wall\nfermions using a single conjugate gradient algorithm is of the same order of\nmagnitude as that of implementing the overlap Dirac operator directly using two\nnested conjugate gradient algorithms. At a cost of about a factor of two in\noperation count it is possible to make the memory usage of direct\nimplementations of the overlap Dirac operator independent of the accuracy of\nthe approximation to the sign function and of the same order as that of\nstandard Wilson fermions."
    },
    {
        "anchor": "Renormalization group flow and fixed point of the lattice topological\n  charge in the 2-d O(3) sigma-model: We study the renormalization group evolution up to the fixed point of the\nlattice topological susceptibility in the 2-d O(3) non-linear sigma-model. We\nstart with a discretization of the continuum topological charge by a local\ncharge density, polynomial in the lattice fields. Among the different choices\nwe propose also a Symanzik--improved lattice topological charge. We check step\nby step in the renormalization group iteration the progressive dumping of\nquantum fluctuations, which are responsible for the additive and multiplicative\nrenormalizations of the lattice topological susceptibility with respect to the\ncontinuum definition. We find that already after three iterations these\nrenormalizations are negligible and an excellent approximation of the fixed\npoint is achieved. We also check by an explicit calculation that the assumption\nof slowly varying fields in iterating the renormalization group does not lead\nto a good approximation of the fixed point charge operator.",
        "positive": "Recent results on topology on the lattice (in memory of Pierre van Baal): Memorizing Pierre van Baal we will shortly review his life and his scientific\nachievements. Starting then with some basics in gauge field topology we mainly\nwill discuss recent efforts in determining the topological susceptibility in\nlattice QCD."
    },
    {
        "anchor": "Singlet baryons in the graded symmetry approach to partially quenched\n  QCD: Progress in the calculation of the electromagnetic properties of baryon\nexcitations in lattice QCD is presenting new challenges in the determination of\nsea-quark loop contributions to matrix elements. A reliable estimation of the\nsea-quark loop contributions presents a pressing issue in the accurate\ncomparison of lattice QCD results with experiment. In this article, an\nextension of the graded symmetry approach to partially quenched QCD is\npresented, which builds on previous theory by explicitly including\nflavor-singlet baryons in its construction. The formalism takes into account\nthe interactions among both octet and singlet baryons, octet mesons, and their\nghost counterparts; the latter enables the isolation of the quark-flow\ndisconnected sea-quark loop contributions. The introduction of the\nflavor-singlet states anticipates the application of the method to baryon\nexcitations such as the lowest-lying odd-parity Lambda baryon, the\nLambda(1405), which is considered in detail as a worked example.",
        "positive": "Study of a lattice 2-group gauge model: Gauge theories admit a generalisation in which the gauge group is replaced by\na finer algebraic structure, known as a 2-group. The first model of this type\nis a Topological Quantum Field Theory introduced by Yetter. We discuss a common\ngeneralisation of both the Yetter's model and Yang-Mills theory and in\nparticular we focus on the lattice formulation of such model for finite\n2-groups. In the second part we present a particular realization based on a\n2-group constructed from $\\mathbb Z_4$ groups. In the selected model,\nindependent degrees of freedom are associated to both links and faces of a\nfour-dimensional lattice and are subject to a certain constraint. We present\nthe details of this construction, discuss the expected dynamics in different\nregions of phase space and show numerical results from Monte Carlo simulations\ncorroborating these expectations."
    },
    {
        "anchor": "Unquenching the topological susceptibility with an overlap action: We estimate the quark-mass dependence of the topological susceptibility with\ndynamical overlap and clover fermions. Unquenching effects on the\nsusceptibility turn out to be well approximated by a reweighting of a quenched\nensemble with a low-eigenmode truncation of the fermionic determinant. We find\nthat it is most likely due to the explicit chiral symmetry breaking of the\nfermion action that present day dynamical simulations do not show the expected\nsuppression of the topological susceptibility.",
        "positive": "Excited charmonium spectrum from anisotropic lattices: We present our final results for the excited charmonium spectrum from a\nquenched calculation using a fully relativistic anisotropic lattice QCD action.\nA detailed excited charmonium spectrum is obtained, including both the exotic\nhybrids (with $J^{PC} = 1^{-+}, 0^{+-}, 2^{+-}$) and orbitally excited mesons\n(with orbital angular momentum up to 3). Using three different lattice spacings\n(0.197, 0.131, and 0.092 fm), we perform a continuum extrapolation of the\nspectrum. We convert our results in lattice units to physical values using\nlattice scales set by the $^1P_1-1S$ splitting. The lowest lying exotic hybrid\n$1^{-+}$ lies at 4.428(41) GeV, slightly above the $D^{**}D$ (S+P wave)\nthreshold of 4.287 GeV. Another two exotic hybrids $0^{+-}$ and $2^{+-}$ are\ndetermined to be 4.70(17) GeV and 4.895(88) GeV, respectively. Our finite\nvolume analysis confirms that our lattices are large enough to accommodate all\nthe excited states reported here."
    },
    {
        "anchor": "Chiral crossover in QCD at zero and non-zero chemical potentials: We present results for pseudo-critical temperatures of QCD chiral crossovers\nat zero and non-zero values of baryon ($B$), strangeness ($S$), electric charge\n($Q$), and isospin ($I$) chemical potentials $\\mu_{X=B,Q,S,I}$. The results\nwere obtained using lattice QCD calculations carried out with two degenerate up\nand down dynamical quarks and a dynamical strange quark, with quark masses\ncorresponding to physical values of pion and kaon masses in the continuum\nlimit. By parameterizing pseudo-critical temperatures as $ T_c(\\mu_X) = T_c(0)\n\\left[ 1 -\\kappa_2^{X}(\\mu_{X}/T_c(0))^2 -\\kappa_4^{X}(\\mu_{X}/T_c(0))^4\n\\right] $, we determined $\\kappa_2^X$ and $\\kappa_4^X$ from Taylor expansions\nof chiral observables in $\\mu_X$. We obtained a precise result for\n$T_c(0)=(156.5\\pm1.5)\\;\\mathrm{MeV}$. For analogous thermal conditions at the\nchemical freeze-out of relativistic heavy-ion collisions, i.e.,\n$\\mu_{S}(T,\\mu_{B})$ and $\\mu_{Q}(T,\\mu_{B})$ fixed from strangeness-neutrality\nand isospin-imbalance, we found $\\kappa_2^B=0.012(4)$ and\n$\\kappa_4^B=0.000(4)$. For $\\mu_{B}\\lesssim300\\;\\mathrm{MeV}$, the chemical\nfreeze-out takes place in the vicinity of the QCD phase boundary, which\ncoincides with the lines of constant energy density of\n$0.42(6)\\;\\mathrm{GeV/fm}^3$ and constant entropy density of\n$3.7(5)\\;\\mathrm{fm}^{-3}$.",
        "positive": "Non-perturbative beta-function in SU(2) lattice gauge fields\n  thermodynamics: The new method of nonperturbative calculation of the beta function in the\nlattice gauge theory is proposed. The method is based on the finite size\nscaling hypothesis."
    },
    {
        "anchor": "Ergodicity and the Classical Lambda Phi^4 Lattice Field Theory: In this talk we present some studies in the approach to equilibrium of the\nclassical lambda phi^4 theory on the lattice, giving particular emphasis to its\npedagogical usefulness in the context of classical statistical field theory\n(such as both the analytical and numerical evaluation of correlation\nfunctions), as well as in the context of statistical mechanics (such as the\nequivalence of ensembles in the thermodynamic limit). Since the quartic term\ncould be regarded as a smooth perturbation to the (integrable) gaussian theory,\nwe also discuss the connection of our results with the KAM theorem, showing\nthat the ergodic and non-ergodic regimes are not sharply separated.",
        "positive": "Disconnected Loop Subtraction Methods in Lattice QCD: Noise subtraction methods are a set of techniques that aim to reduce the\nvariance of signals in LQCD which are often flooded with noise. The standard\napproach is a pertubative subtraction. In this work, we demonstrate the\nabilities of our new noise subtraction methods with methods which show\nconsiderable improvement over pertubative subtraction in the reduction of the\nvariance for the set of LQCD operators that were studied. The methods were\ntested at $\\kappa_{crit}$ on quenched configurations, as well as on dynamical\nquark configurations at $\\kappa = 0.1453$. A significant improvement in the\nreduction of operator variance was observed in both cases."
    },
    {
        "anchor": "Dynamical flavour dependence of static heavy meson decay constants on\n  the lattice: We study the dynamical flavour dependence of the lattice estimates of the\nheavy meson decay constant in the static limit. We perform the analysis by\nconsidering negative flavour numbers and by extrapolating the results to\npositive values. We observe a sizeable flavour dependence which increases the\nquenched estimates.",
        "positive": "Gluon-propagator functional form in the Landau gauge in SU(3) lattice\n  QCD: Yukawa-type gluon propagator and anomalous gluon spectral function: We study the gluon propagator $D_{\\mu\\nu}^{ab}(x)$ in the Landau gauge in\nSU(3) lattice QCD at $\\beta$ = 5.7, 5.8, and 6.0 at the quenched level. The\neffective gluon mass is estimated as $400 \\sim 600$MeV for $r \\equiv (x_\\alpha\nx_\\alpha)^{1/2} = 0.5 \\sim 1.0$ fm. Through the functional-form analysis of\n$D_{\\mu\\nu}^{ab}(x)$ obtained in lattice QCD, we find that the Landau-gauge\ngluon propagator $D_{\\mu\\mu}^{aa}(r)$ is well described by the Yukawa-type\nfunction $e^{-mr}/r$ with $m \\simeq 600$MeV for $r = 0.1 \\sim 1.0$ fm in the\nfour-dimensional Euclidean space-time. In the momentum space, the gluon\npropagator $\\tilde D_{\\mu\\mu}^{aa}(p^2)$ with $(p^2)^{1/2}= 0.5 \\sim 3$ GeV is\nfound to be well approximated with a new-type propagator of $(p^2+m^2)^{-3/2}$,\nwhich corresponds to the four-dimensional Yukawa-type propagator. Associated\nwith the Yukawa-type gluon propagator, we derive analytical expressions for the\nzero-spatial-momentum propagator $D_0(t)$, the effective mass $M_{\\rm eff}(t)$,\nand the spectral function $\\rho(\\omega)$ of the gluon field. The mass parameter\n$m$ turns out to be the effective gluon mass in the infrared region of $\\sim$\n1fm. As a remarkable fact, the obtained gluon spectral function $\\rho(\\omega)$\nis almost negative-definite for $\\omega >m$, except for a positive\n$\\delta$-functional peak at $\\omega=m$."
    },
    {
        "anchor": "I=2 Pion Scattering Phase Shift with Wilson Fermions: We present results of phase shift for I=2 $S$-wave $\\pi\\pi$ system with the\nWilson fermions in the quenched approximation. The finite size method proposed\nby L\\\"uscher is employed, and calculations are carried out at $\\beta=5.9$\n($a^{-1}=1.934(16)$ GeV from $m_\\rho$) on $24^3 \\times 60$, $32^3 \\times 60$,\nand $48^3 \\times 60$ lattices.",
        "positive": "Flavor symmetry breaking in lattice QCD with a mixed action: We study the phase structure of mixed-action QCD with two Wilson sea quarks\nand any number of chiral valence quarks (and ghosts), starting from the chiral\nlagrangian. A priori, the effective theory allows for a rich phase structure,\nincluding a phase with a condensate made of sea and valence quarks. In such a\nphase, mass eigenstates would become admixtures of sea and valence fields, and\npure-sea correlation functions would depend on the parameters of the valence\nsector, in contradiction with the actual setup of mixed-action simulations.\nUsing that the spectrum of the chiral Dirac operator has a gap for nonzero\nquark mass we prove that spontaneous symmetry breaking of the flavor symmetries\ncan only occur within the sea sector. This rules out a mixed condensate, and\nimplies restrictions on the low-energy constants of the effective theory."
    },
    {
        "anchor": "Deconfinement critical point of lattice QCD with $N_{\\rm f}=2$ Wilson\n  fermions: The ${\\rm SU}(3)$ pure gauge theory exhibits a first-order thermal\ndeconfinement transition due to spontaneous breaking of its global $Z_3$ center\nsymmetry. When heavy dynamical quarks are added, this symmetry is broken\nexplicitly and the transition weakens with decreasing quark mass until it\ndisappears at a critical point. We compute the critical hopping parameter and\nthe associated pion mass for lattice QCD with $N_f=2$ degenerate standard\nWilson fermions on $N_\\tau\\in\\{6,8,10\\}$ lattices, corresponding to lattice\nspacings $a=0.12\\, {\\rm fm}$, $a=0.09\\, {\\rm fm}$, $a=0.07\\, {\\rm fm}$,\nrespectively. Significant cut-off effects are observed, with the first-order\nregion growing as the lattice gets finer. While current lattices are still too\ncoarse for a continuum extrapolation, we estimate $m_\\pi^c\\approx 4 {\\rm GeV}$\nwith a remaining systematic error of $\\sim 20\\%$. Our results allow to assess\nthe accuracy of the LO and NLO hopping expanded fermion determinant used in the\nliterature for various purposes. We also provide a detailed investigation of\nthe statistics required for this type of calculation, which is useful for\nsimilar investigations of the chiral transition.",
        "positive": "Overlap Valence on 2+1 Flavor Domain Wall Fermion Configurations with\n  Deflation and Low-mode Substitution: The overlap fermion propagator is calculated on 2+1 flavor domain wall\nfermion gauge configurations on 16^3 x 32, 24^3 x 64 and 32^3 x 64 lattices.\nWith HYP smearing and low eigenmode deflation, it is shown that the inversion\nof the overlap operator can be expedited by ~ 20 times for the 16^3 x 32\nlattice and ~ 80 times for the 32^3 x 64 lattice. Through the study of\nhyperfine splitting, we found that the O(m^2a^2) error is small and these\ndynamical fermion lattices can adequately accommodate quark mass up to the\ncharm quark. The low energy constant \\Delta_{mix} which characterizes the\ndiscretization error of the pion made up of a pair of sea and valence quarks in\nthis mixed action approach is calculated via the scalar correlator with\nperiodic and anti-periodic boundary conditions. It is found to be small which\nshifts a 300 MeV pion mass by ~ 10 to 19 MeV on these sets of lattices. We have\nstudied the signal-to-noise issue of the noise source for the meson and baryon.\nIt is found that the many-to-all meson and baryon correlators with Z_3 grid\nsource and low eigenmode substitution is efficient in reducing errors for the\ncorrelators of both mesons and baryons. With 64-point Z_3 grid source and\nlow-mode substitution, it can reduce the statistical errors of the light quark\n(m_{\\pi} ~ 200 - 300 MeV) meson and nucleon correlators by a factor of ~ 3-4 as\ncompared to the point source. The Z_3 grid source itself can reduce the errors\nof the charmonium correlators by a factor of ~ 3."
    },
    {
        "anchor": "Baryon-Baryon Bound States From First Principles: We determine baryon-baryon bound states in 3+1 dimensional ${\\rm SU}(3)$\nlattice QCD with two flavors, $4\\times 4$ spin matrices, and in an imaginary\ntime formulation. For small hopping parameter, $\\kappa>0$, and large glueball\nmass (strong coupling), we show the existence of three-quark isospin 1/2\nparticles (proton and neutron) and isospin 3/2 baryons (delta particles), with\nasymptotic masses $-3\\ln\\kappa$ and isolated dispersion curves. We only\nconsider the existence of bound states of total isospin $I=0,3$. Using a ladder\napproximation to a lattice Bethe-Salpeter equation, baryon-baryon bound states\nare found in these two sectors, with asymptotic masses $-6\\ln\\kappa$ and\nbinding energies of order $\\kappa^2$. The dominant baryon-baryon interaction is\nan energy-independent spatial range-one potential with an ${\\cal O}(\\kappa^2)$\nstrength. There is also attraction arising from gauge field correlations\nassociated with six overlapping bonds, but it is counterbalanced by Pauli\nrepulsion to give a vanishing zero-range potential. The overall range-one\npotential results from a quark, antiquark exchange with {\\it no} meson exchange\ninterpretation; the repulsive or attractive nature of the interaction does\ndepend on the isospin and spin of the two-baryon state.",
        "positive": "Performance of the GPU inverters with Chroma+QUDA for various fermion\n  actions: We present our progress on the Chroma interfaces of the twisted-mass, HISQ\n(highly improved staggered quark) and overlap fermion inverters using QUDA."
    },
    {
        "anchor": "Use of Schwinger-Dyson equation in constructing an approximate\n  trivializing map: We construct an approximate trivializing map by using a Schwinger-Dyson\nequation. The advantage of this method is that: (1) The basis for the flow\nkernel can be chosen arbitrarily by hand. (2) It can be applied to the general\naction of interest. (3) The coefficients in the kernel are determined by\nlattice estimates of the observables, which does not require analytic\ncalculations beforehand. We perform the HMC with the effective action obtained\nby the Schwinger-Dyson method, and show that we can have better control of the\neffective action than the known $t$-expansion construction. However, the\nalgorithmic overhead is still large and overwhelming the gain though faster\ndecorrelation is observed for long-range observables in some cases. This\ncontribution reports the preliminary results of this attempt.",
        "positive": "Numerical study of plasmon properties in the SU(2)-Higgs model: Using the (effective) classical approximation, we compute numerically\ntime-dependent correlation functions in the SU(2)-Higgs model around the\nelectroweak phase transition, for $m_H \\approx m_W$. The parameters of the\nclassical model have been determined previously by the dimensional reduction\nrelations for time-independent correlators. The $H$ and $W$ correlation\nfunctions correspond to gauge invariant fields. They show damped oscillatory\nbehavior from which we extract frequencies $\\om$ and damping rates $\\gm$. In\nthe Higgs phase the damping rates have roughly the values obtained in analytic\ncalculations in the quantum theory. In the plasma phase (where analytic\nestimates for gauge invariant fields are not available), the damping rate\nassociated with $H$ is an order of magnitude larger than in the Higgs phase,\nwhile the $W$ correlator appears to be overdamped, with a small rate. The\nfrequency $\\om_H$ shows a clear dip at the transition. The results are\napproximately independent of the lattice spacing, but this appears to be\ncompatible with the lattice spacing dependence expected from perturbation\ntheory."
    },
    {
        "anchor": "Glueball spectral densities from the lattice: The propagator of a physical degree of freedom ought to obey a\nK\\\"{a}ll\\'{e}n-Lehmann spectral representation, with positive spectral density.\nThe latter quantity is directly related to a cross section based on the optical\ntheorem. The spectral density is a crucial ingredient of a quantum field theory\nwith elementary and bound states, with a direct experimental connection as the\nmasses of the excitations reflect themselves into (continuum)\n$\\delta$-singularities. In usual lattice simulational approaches to the QCD\nspectrum the spectral density itself is not accessed. The (bound state) masses\nare extracted from the asymptotic exponential decay of the two-point function.\nGiven the importance of the spectral density, each nonperturbative continuum\napproach to QCD should be able to adequately describe it or to take into proper\naccount. In this work, we wish to present a first trial in extracting an\nestimate for the scalar glueball spectral density in SU(3) gluodynamics using\nlattice gauge theory.",
        "positive": "On the Continuum Limit of the Discrete Regge Model in 4d: The Regge Calculus approximates a continuous manifold by a simplicial\nlattice, keeping the connectivities of the underlying lattice fixed and taking\nthe edge lengths as degrees of freedom. The Discrete Regge model employed in\nthis work limits the choice of the link lengths to a finite number. This makes\nthe computational evaluation of the path integral much faster. A main concern\nin lattice field theories is the existence of a continuum limit which requires\nthe existence of a continuous phase transition. The recently conjectured\nsecond-order transition of the four-dimensional Regge skeleton at negative\ngravity coupling could be such a candidate. We examine this regime with Monte\nCarlo simulations and critically discuss its behavior."
    },
    {
        "anchor": "A strategy for implementing non-perturbative renormalisation of\n  heavy-light four-quark operators in the static approximation: We discuss the renormalisation properties of the complete set of $\\Delta B =\n2$ four-quark operators with the heavy quark treated in the static\napproximation. We elucidate the role of heavy quark symmetry and other symmetry\ntransformations in constraining their mixing under renormalisation. By\nemploying the Schroedinger functional, a set of non-perturbative\nrenormalisation conditions can be defined in terms of suitable correlation\nfunctions. As a first step in a fully non-perturbative determination of the\nscale-dependent renormalisation factors, we evaluate these conditions in\nlattice perturbation theory at one loop. Thereby we verify the expected mixing\npatterns and determine the anomalous dimensions of the operators at NLO in the\nSchroedinger functional scheme. Finally, by employing twisted-mass QCD it is\nshown how finite subtractions arising from explicit chiral symmetry breaking\ncan be avoided completely.",
        "positive": "Parameters of the lowest order chiral Lagrangian from fermion\n  eigenvalues: Recent advances in Random Matrix Theory enable one to determine the\npseudoscalar decay constant from the response of eigenmodes of quenched\nfermions to an imaginary isospin chemical potential. We perform a pilot test of\nthis idea, from simulations with two flavors of dynamical overlap fermions."
    },
    {
        "anchor": "Coupled channel approach to strangeness S = -2 baryon-bayron\n  interactions in Lattice QCD: The baryon-baryon interactions with strangeness S = -2 with the flavor SU(3)\nbreaking are calculated for the first time by using the HAL QCD method extended\nto coupled channel system in lattice QCD. The potential matrices are extracted\nfrom the Nambu-Bethe-Salpeter wave functions obtained by the 2+1 flavor gauge\nconfigurations of CP-PACS/JLQCD Collaborations with a physical volume of 1.93\nfm cubed and with m_pi/m_K = 0.96, 0.90, 0.86. The spatial structure and the\nquark mass dependence of the potential matrix in the baryon basis and in the\nSU(3) basis are investigated.",
        "positive": "Highly Improved Naive and Staggered Fermions: We present a new action for highly improved staggered fermions. We show that\nperturbative calculations for the new action are well-behaved where those of\nthe conventional staggered action are badly behaved. We discuss the effects of\nthe new terms in controlling flavor mixing, and discuss the design of operators\nfor the action."
    },
    {
        "anchor": "Pseudoscalar and vector meson form factors from lattice QCD: We present a study of the pseudoscalar and vector meson form factors,\ncalculated using the Fat-Link Irrelevant Clover (FLIC) action in the framework\nof Quenched Lattice QCD. Of particular interest is the determination of a\nnegative quadrupole moment, indicating that the $\\rho$ meson is not spherically\nsymmetric.",
        "positive": "Deconfining transition in Full QCD: We present evidence that in full QCD with two dynamical quarks confinement is\nproduced by dual superconductivity of the vacuum as in the quenched theory.\nPreliminary information is obtained on the nature of the deconfining\ntransition."
    },
    {
        "anchor": "Baryons in Partially-Quenched Chiral Perturbation Theory: I discuss the inclusion of baryons into partially-quenched chiral\nperturbation theory and describe one-loop calculations that have been\nperformed.",
        "positive": "No-go theorem on spontaneous parity breaking revisited: An essential assumption in the Vafa and Witten's theorem on P and CT\nrealization in vector-like theories concerns the existence of a free energy\ndensity in Euclidean space in the presence of any external hermitian symmetry\nbreaking source. We show how this requires the previous assumption that the\nsymmetry is realized in the vacuum. Even if Vafa and Witten's conjecture is\nplausible, actually a theorem is still lacking."
    },
    {
        "anchor": "A variance reduction technique for hadronic correlators with partially\n  twisted boundary conditions: Partially twisted boundary conditions are widely used for improving the\nmomentum resolution in lattice computations of hadronic correlation functions.\nThe method is however expensive since every additional twist requires computing\nadditional propagators. We propose a novel variance reduction technique that\nexploits statistical correlations to reduce the overall cost for computing\ncorrelators with additional twist angles. We explain and demonstrate the method\nfor meson 2pt and 3pt functions.",
        "positive": "An Almost Perfect Quantum Lattice Action for Low-energy SU(2)\n  Gluodynamics: We study various representations of infrared effective theory of SU(2)\nGluodynamics as a (quantum) perfect lattice action. In particular we derive a\nmonopole action and a string model of hadrons from SU(2) Gluodynamics. These\nare lattice actions which give almost cut-off independent physical quantities\neven on coarse lattices. The monopole action is determined by numerical\nsimulations in the infrared region of SU(2) Gluodynamics. The string model of\nhadrons is derived from the monopole action by using BKT transformation. We\nillustrate the method and evaluate physical quantities such as the string\ntension and the mass of the lowest state of the glueball analytically using the\nstring model of hadrons. It turns out that the classical results in the string\nmodel is near to the one in quantum SU(2) Gluodynamics."
    },
    {
        "anchor": "Rare $B$ decays using lattice QCD form factors: In this write-up we review and update our recent lattice QCD calculation of\n$B \\to K^*$, $B_s \\to \\phi$, and $B_s \\to K^*$ form factors [arXiv:1310.3722].\nThese unquenched calculations, performed in the low-recoil kinematic regime,\nprovide a significant improvement over the use of extrapolated light cone sum\nrule results. The fits presented here include further kinematic constraints and\nestimates of additional correlations between the different form factor shape\nparameters. We use these form factors along with Standard Model determinations\nof Wilson coefficients to give Standard Model predictions for several\nobservables [arXiv:1310.3887]. The modest improvements to the form factor fits\nlead to improved determinations of $F_L$, the fraction of longitudinally\npolarized vector mesons, but have little effect on most other observables.",
        "positive": "Finite temperature lattice QCD with GPUs: Graphics Processing Units (GPUs) are being used in many areas of physics,\nsince the performance versus cost is very attractive. The GPUs can be addressed\nby CUDA which is a NVIDIA's parallel computing architecture. It enables\ndramatic increases in computing performance by harnessing the power of the GPU.\nWe present a performance comparison between the GPU and CPU with single\nprecision and double precision in generating lattice SU(2) configurations.\nAnalyses with single and multiple GPUs, using CUDA and OPENMP, are also\npresented. We also present SU(2) results for the renormalized Polyakov loop,\ncolour averaged free energy and the string tension as a function of the\ntemperature."
    },
    {
        "anchor": "Correlations of chiral condensates and quark number densities with\n  static quark sources: We investigate correlation functions of the Polyakov loop and static\nmeson/diquark systems with the chiral condensate and the quark number density\nat finite temperature. In particular the latter observable can give insight in\nthe mechanism of screening and string breaking at finite temperature. We use\nfor our analysis gauge field configurations generated in 2+1 flavor QCD with an\nimproved staggered fermion action with almost physical light quark masses and a\nphysical value of the strange quark mass on lattices with temporal extent Nt=4\nand 6.",
        "positive": "First numerical experiences with overlap fermions based on the Brillouin\n  kernel: Numerical experiences are reported with overlap fermions which employ the\nBrillouin action as a kernel. After discussing the dispersion relations of both\nthe kernel and the resulting chiral action, some of the physics features are\naddressed on quenched backgrounds. We find that the overlap with Brillouin\nkernel is much better localized than the overlap with Wilson kernel. Also a\npreliminary account is given of the cost of the formulation, in terms of CPU\ntime and memory."
    },
    {
        "anchor": "Renormalization of Karsten-Wilczek Quarks on a Staggered Background: The Karsten-Wilczek action is a formulation of minimally doubled fermions on\nthe lattice. It explicitly breaks hypercubic symmetry and introduces three\ncounterterms with respective bare parameters. We present a tuning of the bare\nparameters of the Karsten-Wilczek action on staggered configurations at the\nphysical point. We study the magnitude of the taste-splitting as a function of\nthe lattice spacing.",
        "positive": "From Surface Roughening to QCD String Theory: Surface critical phenomena and the related onset of Goldstone modes represent\nfundamental properties of the confining flux in Quantum Chromodynamics. New\nideas on surface roughening and their implications for lattice studies of quark\nconfinement and string formation are presented. Problems with a simple string\ndescription of the large Wilson surface are discussed."
    },
    {
        "anchor": "A High Statistics Lattice Calculation of The B-meson Binding Energy: We present a high statistics lattice calculation of the B--meson binding\nenergy $\\overline{\\Lambda}$ of the heavy--quark inside the pseudoscalar\nB--meson. Our numerical results have been obtained from several independent\nnumerical simulations at $\\beta=6.0$, $6.2$ and $6.4$, and using, for the meson\ncorrelators, the results obtained by the APE group at the same values of\n$\\beta$. Our best estimate, obtained by combining results at different values\nof $\\beta$, is $\\overline{\\Lambda}=180^{+30}_{-20}$ MeV. For the\n$\\overline{MS}$ running mass, we obtain\n$\\overline{m}_{b}(\\overline{m}_{b})=4.15 \\pm 0.05 \\pm 0.20$ GeV, in reasonable\nagreement with previous determinations. The systematic error is the truncation\nof the perturbative series in the matching condition of the relevant operator\nof the Heavy Quark Effective Theory.",
        "positive": "Issues for the Lattice in Hadron Spectroscopy: Lattice QCD predicts a rich spectroscopy of glueballs and $q\\bar{q}-$glue h\nybrids. I compare these with data and assess the emerging empirical situation.\nQuestions for the lattice are proposed."
    },
    {
        "anchor": "Disconnected diagrams with twisted-mass fermions: The latest results from the Twisted-Mass collaboration on disconnected\ndiagrams at the physical value of the pion mass are presented. In particular,\nwe focus on the sigma terms, the axial charges and the momentum fraction, all\nof them for the nucleon. A detailed error analysis for each observable follows,\nshowing the strengths and weaknesses of the one-end trick. Alternatives are\ndiscussed.",
        "positive": "Graphene, Lattice QFT and Symmetries: Borrowing ideas from tight binding model, we propose a board class of Lattice\nQFT models that are classified by the ADE Lie algebras. In the case of su(N)\nseries, we show that the couplings between the quantum states living at the\nfirst nearest neighbor sites of the lattice $\\mathcal{L}_{su(N)}$ are governed\nby the complex fundamental representations \\underline{${{\\mathbf{N}}}$} and\n$\\bar{{\\mathbf{N}}}$ of $su(N)$; and the second nearest neighbor interactions\nare described by its adjoint $\\underline{\\mathbf{N}} \\otimes \\bar{\\mathbf{N}}$.\nThe lattice models associated with the leading su(2), su(3) and su(4) cases are\nexplicitly studied and their fermionic field realizations are given. It is also\nshown that the su(2) and su(3) models describe respectively the electronic\nproperties of the acetylene chain and the graphene. It is established as well\nthat the energy dispersion of the first nearest neighbor couplings is\ncompletely determined by the $A_{N}$ roots $ \\mathbf{\\alpha}$ through the\ntypical dependence $N/2+\\sum_{roots}\\cos(\\mathbf{k}.\\alpha) $ with $\\mathbf{k}$\nthe wave vector. Other features such as DE extension and other applications are\nalso discussed.\n  Keywords: Tight Binding Model, Graphene, Lattice QFT, ADE Symmetries."
    },
    {
        "anchor": "Zeros of QCD partition function from finite density lattices: Partition function zeros steer the critical behavior of a system. Studying\nfour-flavor lattice QCD at finite temperature and density with the\nWilson-clover fermion action and the Iwasaki gauge action using a\nphase-quenched fermion determinant, we combine statistics from multiple\nchemical potentials to improve sampling of the configuration space, and aim at\nunraveling the movement of zeros in finite systems. Preparing for further\ninvestigations, we discuss methods and criteria used to sieve through complex\nparameter space spanned by $(\\text{Re}\\mu, \\text{Im}\\mu)$ and $(\\text{Re}\\mu,\n\\text{Im}\\beta)$, and present statistically robust zeros of the partition\nfunction.",
        "positive": "The Isgur-Wise Function: After a brief introduction to the Heavy-Quark Effective Theory (HQET), I\nreview the extraction of the Isgur-Wise function from lattice QCD calculations\nof the matrix elements for semi-leptonic decays of heavy-light pseudoscalar\nmesons both into pseudoscalar and into vector mesons. This work is beginning to\ntest the heavy-quark spin-flavour symmetries around the charm mass and to\nindicate the size of $O(1/m_c)$ corrections. An alternative approach to put the\nHQET on the lattice offers the prospect of computing the Isgur-Wise function\ndirectly."
    },
    {
        "anchor": "The Lefschetz thimble and the sign problem: In this talk I review the proposal to formulate quantum field theories (QFTs)\non a Lefschetz thimble, which was put forward to enable Monte Carlo simulations\nof lattice QFTs affected by sign problem. First I will review the theoretical\njustification of the approach, and comment on some open issues. Then, I will\nreview the algorithms that have been proposed and are being tested to represent\nand simulate a lattice QFT on a Lefschetz thimble. In particular, I will review\nthe lessons from the very first models of QFTs that have been studied with this\napproach.",
        "positive": "Evidence for a Critical Behavior in $4D$ Pure Compact QED: We present evidence about a critical behavior of $4D$ compact QED (CQED) pure\ngauge theory. Regularizing the theory on lattices homotopic to a sphere, we\npresent evidence for a critical, i.e. second order like behavior at the\ndeconfinement phase transition for certain values of the coupling parameter\n$\\gamma$."
    },
    {
        "anchor": "Thermal transition temperature from twisted mass QCD: We present the current status of lattice simulations with N_f=2 maximally\ntwisted mass Wilson fermions at finite temperature. In particular, the\ndetermination of the thermal transition temperature is discussed.",
        "positive": "Quark Density in Lattice QC$_2$D at Imaginary and Real Chemical\n  Potential: We study lattice two-color QCD (QC$_2$D) with two flavors of staggered\nfermions at imaginary and real quark chemical potential $\\mu_q$ and $T>T_c$. We\nemploy various methods of analytic continuation of the quark number density\nfrom imaginary to real quark chemical potentials $\\mu_q$, including series\nexpansions as well as based on phenomenological models, and study their\naccuracy by comparing the results to the lattice data. Below the Roberge-Weiss\ntemperature, $T<T_{RW}$, we find that the cluster expansion model provides an\naccurate analytic continuation of the baryon number density in the studied\nrange of chemical potentials. On the other hand, the behavior of the\nreconstructed canonical partition functions indicate that the available models\nmay require corrections at high quark densities. At $T>T_{RW}$ we show that the\nanalytic continuation to the real values of $\\mu_q$ based on trigonometric\nfunctions works equally well with the conventional method based on the Taylor\nexpansion in powers of $\\mu_q$."
    },
    {
        "anchor": "Baryon resonances from a novel fat-link fermion action: We present first results for masses of positive and negative parity excited\nbaryons in lattice QCD using an O(a^2) improved gluon action and a Fat Link\nIrrelevant Clover (FLIC) fermion action in which only the irrelevant operators\nare constructed with fat links. The results are in agreement with earlier\ncalculations of N^* resonances using improved actions and exhibit a clear mass\nsplitting between the nucleon and its chiral partner, even for the Wilson\nfermion action. The results also indicate a splitting between the lowest J^P =\n1/2^- states for the two standard nucleon interpolating fields.",
        "positive": "Finite temperature and delta-regime in the 2-flavor Schwinger model: The Schwinger model is often used as a testbed for conceptual and numerical\napproaches in lattice field theory. Still, some of its rich physical properties\nin anisotropic volumes have not yet been explored. For the multi-flavor finite\ntemperature Schwinger model there is an approximate solution by Hosotani et al.\nbased on bosonization. We perform lattice simulations and check the validity of\nthis approximation in the case of two flavors. Next we exchange the r\\^{o}le of\nthe coordinates to enter the $\\delta$-regime, and measure the dependence of the\nresidual \"pion\" mass on the spatial size, at zero temperature. Our results show\nthat universal features, which were derived by Leutwyler, Hasenfratz and\nNiedermayer referring to quasi-spontaneous symmetry breaking in $d>2$, extend\neven to $d=2$. This enables the computation of the Schwinger model counterpart\nof the pion decay constant $F_{\\pi}$. It is consistent with an earlier\ndetermination by Harada et al. who considered the divergence of the axial\ncurrent in a light-cone formulation, and with analytical results that we\nconjecture from 2d versions of the Witten--Veneziano formula and the\nGell-Mann--Oakes--Renner relation, which suggest $F_{\\pi} = 1/ \\sqrt{2\\pi}$."
    },
    {
        "anchor": "Worldline Approach to Chiral Fermions: We propose to apply ``worldline numerics'' to a numerical calculation of\nquark determinants. The Gross-Neveu model with a U(1) chiral symmetry is\nconsidered as a first test. The worldline approach allows for an analytic\nrenormalisation, and only finite parts of the determinant require a numerical\ncalculation. It is shown that the discretisation of the worldlines, which is\ncentral to the numerical treatment, preserves chiral symmetry exactly.\nNumerical results for a kink configuration as a scalar background field are\nshown and compared with analytical results. The case of finite fermion chemical\npotential is also briefly discussed.",
        "positive": "Pseudoscalar decay constant in the heavy light systems: We discuss the size of the higher order terms in the NRQCD expansion of the\npseudoscalar decay constant. Power law divergences in the matrix elements\ncontributing to the pseudoscalar decay constant are also investigated."
    },
    {
        "anchor": "Topological susceptibility near $T_{c}$ in SU(3) gauge theory: Topological charge susceptibility $\\chi_{t}$ for pure gauge SU(3) theory at\nfinite temperature is studied using anisotropic lattices. The over-improved\nstout-link smoothing method is utilized to calculate the topological charge.\nNear the phase transition point we find a rapid declining behavior for\n$\\chi_{t}$ with values decreasing from $(188(1)\\mathrm{MeV})^{4}$ to\n$(67(3)\\mathrm{MeV})^{4}$ as the temperature increased from zero temperature to\n$1.9T_{c}$ which demonstrates the existence of topological excitations far\nabove $T_{c}$. The 4th order cumulant $c_4$ of topological charge, as well as\nthe ratio $c_4/\\chi_t$ are also investigated. Results of $c_4$ show step-like\nbehavior near $T_c$ while the ratio at high temperature agrees with the value\nas predicted by the diluted instanton gas model.",
        "positive": "Investigating the low moments of the nucleon structure functions in\n  lattice QCD: We highlight QCDSF/UKQCD Collaboration's recent developments on computing the\nCompton amplitude directly via an implementation of the second order\nFeynman-Hellmann theorem. As an application, we compute the nucleon Compton\ntensor across a range of photon virtuality at an unphysical quark mass. This\nenables us to study the $Q^2$ dependence of the low moments of the nucleon\nstructure functions in a lattice calculation for the first time. We present\nsome selected results for the moments of the $F_1$, $F_2$ and $F_L$ structure\nfunctions and discuss their implications."
    },
    {
        "anchor": "Triviality of $\u03c6^4_4$ theory: small volume expansion and new data: We study a renormalized coupling g and mass m in four dimensional phi^4\ntheory on tori with finite size z=mL. Precise numerical values close to the\ncontinuum limit are reported for z=1,2,4, based on Monte Carlo simulations\nperformed in the equivalent all-order strong coupling reformulation. Ordinary\nrenormalized perturbation theory is found to work marginally at z=2 and and to\nfail at z=1. By exactly integrating over the constant field mode we set up a\nrenormalized expansion in z and compute three nontrivial orders. These results\nreasonably agree with the numerical data at small z. In the new expansion, the\nuniversal continuum limit exists as expected from multiplicative\nrenormalizability. The triviality scenario is corroborated with significant\nprecision.",
        "positive": "Spin Glasses on Thin Graphs: In a recent paper we found strong evidence from simulations that the\nIsingantiferromagnet on ``thin'' random graphs - Feynman diagrams - displayed\namean-field spin glass transition. The intrinsic interest of considering such\nrandom graphs is that they give mean field results without long range\ninteractions or the drawbacks, arising from boundary problems, of the Bethe\nlattice. In this paper we reprise the saddle point calculations for the Ising\nand Potts ferromagnet, antiferromagnet and spin glass on Feynman diagrams. We\nuse standard results from bifurcation theory that enable us to treat an\narbitrary number of replicas and any quenched bond distribution. We note the\nagreement between the ferromagnetic and spin glass transition temperatures thus\ncalculated and those derived by analogy with the Bethe lattice, or in previous\nreplica calculations. We then investigate numerically spin glasses with a plus\nor minus J bond distribution for the Ising and Q=3,4,10,50 state Potts models,\npaying particular attention to the independence of the spin glass transition\nfrom the fraction of positive and negative bonds in the Ising case and the\nqualitative form of the overlap distribution in all the models. The parallels\nwith infinite range spin glass models in both the analytical calculations and\nsimulations are pointed out."
    },
    {
        "anchor": "Chirally rotated Schroedinger functional: non-perturbative tuning in the\n  quenched approximation: The use of chirally rotated boundary conditions provides a formulation of the\nSchroedinger functional that is compatible with automatic O(a)-improvement of\nWilson fermions in the bulk. The elimination of bulk O(a) terms requires the\nnon-perturbative tuning of the critical mass and one additional boundary\ncounterterm. We present the results of such a tuning in the quenched\napproximation at three values of the renormalised gauge coupling and for a\nrange of lattice spacings.",
        "positive": "Lattice Fermions and the Chiral Anomaly: We show in the Wilson model that the contribution of the regular mass term to\nthe four-divergence of the axial vector current in weak coupling perturbation\ntheory is not zero in the chiral limit and is precisely the axial anomaly.\nExplicit breaking of chiral symmetry in the Wilson term is not relevant for the\nresult. The ABJ anomaly is generated by the fermion mass term also with a\nchirally symmetric irrelevant term."
    },
    {
        "anchor": "Chiral Extrapolation of Lattice Data for Heavy Meson Hyperfine\n  Splittings: We investigate the chiral extrapolation of the lattice data for the\nlight-heavy meson hyperfine splittings D^*-D and B^*-B to the physical region\nfor the light quark mass. The chiral loop corrections providing non-analytic\nbehavior in m_\\pi are consistent with chiral perturbation theory for heavy\nmesons. Since chiral loop corrections tend to decrease the already too low\nsplittings obtained from linear extrapolation, we investigate two models to\nguide the form of the analytic background behavior: the constituent quark\npotential model, and the covariant model of QCD based on the ladder-rainbow\ntruncation of the Dyson-Schwinger equations. The extrapolated hyperfine\nsplittings remain clearly below the experimental values even allowing for the\nmodel dependence in the description of the analytic background.",
        "positive": "Cutoff Effects in O(N) Nonlinear Sigma Models: In the nonlinear O(N) sigma model at N=3 unexpected cutoff effects have been\nfound before with standard discretizations and lattice spacings. Here the\nsituation is analyzed further employing additional data for the step scaling\nfunction of the finite volume massgap at N=3,4,8 and a large N-study of the\nleading as well as next-to-leading terms in 1/N. The latter exact results are\ndemonstrated to follow Symanzik's form of the asymptotic cutoff dependence. At\nthe same time, when fuzzed with artificial statistical errors and then fitted\nlike the Monte Carlo results, a picture similar to N=3 emerges. We hence cannot\nconclude a truly anomalous cutoff dependence but only relatively large cutoff\neffects, where the logarithmic component is important. Their size shrinks at\nlarger N, but the structure remains similar. The large N results are\nparticularly interesting as we here have exact nonperturbative control over an\nasymptotically free model both in the continuum limit and on the lattice."
    },
    {
        "anchor": "Properties of the deconfining phase transition in SU(N) gauge theories: We extend our earlier investigation of the finite temperature deconfinement\ntransition in SU(N) gauge theories, with the emphasis on what happens as N->oo.\nWe calculate the latent heat in the continuum limit, and find the expected\nquadratic in N behaviour at large N. We confirm that the phase transition,\nwhich is second order for SU(2) and weakly first order for SU(3), becomes\nrobustly first order for N>3 and strengthens as N increases. As an aside, we\nexplain why the SU(2) specific heat shows no sign of any peak as T is varied\nacross what is supposedly a second order phase transition. We calculate the\neffective string tension and electric gluon masses at T=Tc confirming the\ndiscontinuous nature of the transition for N>2. We explicitly show that the\nlarge-N `spatial' string tension does not vary with T for T<Tc and that it is\ndiscontinuous at T=Tc. For T>Tc it increases as T-squared to a good\napproximation, and the k-string tension ratios closely satisfy Casimir Scaling.\nWithin very small errors, we find a single Tc at which all the k-strings\ndeconfine, i.e. a step-by-step breaking of the relevant centre symmetry does\nnot occur. We calculate the interface tension but are unable to distinguish\nbetween linear or quadratic in N variations, each of which can lead to a\nstriking but different N=oo deconfinement scenario. We remark on the location\nof the bulk phase transition, which bounds the range of our large-N\ncalculations on the strong coupling side, and within whose hysteresis some of\nour larger-N calculations are performed.",
        "positive": "Bottomonia screening masses from $2 + 1$ flavor QCD: The sequential melting of the bottomonium states is one of the important\nsignals for the existence of a quark gluon plasma. The study of bottomonia\nspectral functions on the lattice is a difficult task for many reasons.\nCalculations based on NRQCD, that are commonly used for such purpose, are not\napplicable at high temperatures. In this work we propose a new method to study\nthis problem by calculating the spatial screening masses of bottomonium states.\nWe calculate the spatial meson correlators and extract the screening masses for\nmesons in different quantum channels using highly improved staggered quark\n(HISQ) action for bottom quarks and dynamical $2+1$ flavor QCD HISQ gauge\nconfigurations. The typical lattices we choose are of size $N_s^3 \\times\nN_\\tau$ where $N_s=4 N_\\tau$ and $N_\\tau=8, 10, 12$. We consider the\ntemperature range $T = 300$-$1000$ MeV. We show that for $T > 500$ MeV the\ntemperature dependence of the screening masses of the ground state bottomonia\nare compatible with the expectations based on uncorrelated quark anti-quark\npairs."
    },
    {
        "anchor": "Quark orbital dynamics in the proton from Lattice QCD -- from Ji to\n  Jaffe-Manohar orbital angular momentum: Given a Wigner distribution simultaneously characterizing quark transverse\npositions and momenta in a proton, one can directly evaluate their\ncross-product, i.e., quark orbital angular momentum. The aforementioned\ndistribution can be obtained by generalizing the proton matrix elements of\nquark bilocal operators which define transverse momentum-dependent parton\ndistributions (TMDs); the transverse momentum information is supplemented with\ntransverse position information by introducing an additional nonzero momentum\ntransfer. A gauge connection between the quarks must be specified in the quark\nbilocal operators; the staple-shaped gauge link path used in TMD calculations\nyields the Jaffe-Manohar definition of orbital angular momentum, whereas a\nstraight path yields the Ji definition. An exploratory lattice calculation,\nperformed at the pion mass m_pi = 518 MeV, is presented which\nquasi-continuously interpolates between the two definitions and demonstrates\nthat their difference can be clearly resolved. The resulting Ji orbital angular\nmomentum is confronted with traditional evaluations based on Ji's sum rule.\nJaffe-Manohar orbital angular momentum is enhanced in magnitude compared to its\nJi counterpart.",
        "positive": "On the Mass Spectrum of the SU(2) Higgs Model in 2+1 Dimensions: We calculate the masses of the low-lying states with quantum numbers\n$J^{PC}=0^{++},1^{--}$ in the Higgs and confinement regions of the\nthree-dimensional SU(2) Higgs model, which plays an important r\\^ole in the\ndescription of the thermodynamic properties of the standard model at finite\ntemperatures. We extract the masses from correlation functions of\ngauge-invariant operators which are calculated by means of a lattice Monte\nCarlo simulation. The projection properties of our lattice operators onto the\nlowest states are greatly improved by the use of smearing techniques. We also\nconsider cross correlations between various operators with the same quantum\nnumbers. From these the mass eigenstates are determined by means of a\nvariational calculation. In the symmetric phase, we find that some of the\nground state masses are about 30\\% lighter than those reported from previous\nsimulations. We also obtain the masses of the first few excited states in the\nsymmetric phase. Remarkable among these is the occurrence of a $0^{++}$ state\ncomposed almost entirely of gauge degrees of freedom. The mass of this state,\nas well as that of its first excitations, is nearly identical to the\ncorresponding glueball states in three-dimensional SU(2) pure gauge theory,\nindicating an approximate decoupling of the pure gauge sector from the Higgs\nsector of the model. We perform a detailed study of finite size effects and\nextrapolate the lattice mass spectrum to the continuum."
    },
    {
        "anchor": "Status of APEmille: This paper presents the status of the APEmille project, which is essentially\ncompleted, as far as machine development and construction is concerned. Several\nlarge installations of APEmille are in use for physics production runs leading\nto many new results presented at this conference. This paper briefly summarizes\nthe APEmille architecture, reviews the status of the installations and presents\nsome performance figures for physics codes.",
        "positive": "Improved gluonic actions on anisotropic lattices: The use of novel perturbatively-improved gluonic actions on anisotropic\nlattices in which the temporal spacing is much smaller than that in the spatial\ndirections is discussed. Such actions permit more efficient measurements of\nnoisy correlation functions, such as glueball correlators, on coarse lattices.\nA derivation of these actions at tree-level is outlined; mean-field link\nrenormalization plays a crucial role in their construction. Results for the\nlow-lying glueball masses and the heavy-quark potential are presented."
    },
    {
        "anchor": "Chiral behavior of pseudo-Goldstone boson masses and decay constants in\n  2+1 flavor QCD: We present preliminary results for the chiral behavior of charged\npseudo-Goldstone-boson masses and decay constants. These are obtained in\nsimulations with N_f=2+1 flavors of tree-level, O(a)-improved Wilson sea\nquarks. In these simulations, mesons are composed of either valence quarks\ndiscretized in the same way as the sea quarks (unitary simulations) or of\noverlap valence quarks (mixed-action simulations). We find that the chiral\nbehavior of the pseudoscalar meson masses in the mixed-action calculations\ncannot be explained with continuum, partially-quenched chiral perturbation\ntheory. We show that the inclusion of O(a^2) unitarity violations in the chiral\nexpansion resolves this discrepancy and that the size of the unitarity\nviolations required are consistent with those which we observe in the\nzero-momentum, scalar-isotriplet-meson propagator.",
        "positive": "Scaling behavior of the four-point renormalized coupling constant in the\n  two dimensional O(2) and O(3) non-linear sigma models: We report thermodynamic values of four-point renormalized coupling constant\ncalculated by Monte Carlo simulations in the continuum limits of the lattice\nversions of the two-dimensional O(2) and O(3) non-linear sigma models. In each\ncase the critical index of the coupling constant vanishes, which leads to\nhyperscaling (non-triviality)."
    },
    {
        "anchor": "Proton decay matrix elements with domain-wall fermions: Hadronic matrix elements of operators relevant to nucleon decay in grand\nunified theories are calculated numerically using lattice QCD. In this context,\nthe domain-wall fermion formulation, combined with non-perturbative\nrenormalization, is used for the first time. These techniques bring reduction\nof a large fraction of the systematic error from the finite lattice spacing.\nOur main effort is devoted to a calculation performed in the quenched\napproximation, where the direct calculation of the nucleon to pseudoscalar\nmatrix elements, as well as the indirect estimate of them from the nucleon to\nvacuum matrix elements, are performed. First results, using two flavors of\ndynamical domain-wall quarks for the nucleon to vacuum matrix elements are also\npresented to address the systematic error of quenching, which appears to be\nsmall compared to the other errors. Our results suggest that the representative\nvalue for the low energy constants from the nucleon to vacuum matrix elements\nare given as |alpha| simeq |beta| simeq 0.01 GeV^3. For a more reliable\nestimate of the physical low energy matrix elements, it is better to use the\nrelevant form factors calculated in the direct method. The direct method tends\nto give smaller value of the form factors, compared to the indirect one, thus\nenhancing the proton life-time; indeed for the pi^0 final state the difference\nbetween the two methods is quite appreciable.",
        "positive": "A Euclidean Lattice Formulation of D=5 Maximally Supersymmetric\n  Yang-Mills Theory: We construct lattice action for five-dimensional maximally supersymmetric\nYang-Mills theory. This supersymmetric lattice formulation can be used to\nexplore the non-perturbative regime of the continuum target theory, which has a\nknown gravitational dual."
    },
    {
        "anchor": "Recent results on QCD thermodynamics: lattice QCD versus Hadron\n  Resonance Gas model: We present our most recent investigations on the QCD cross-over transition\ntemperatures with 2+1 staggered flavours and one-link stout improvement [JHEP\n1009:073, 2010]. We extend our previous two studies [Phys. Lett. B643 (2006)\n46, JHEP 0906:088 (2009)] by choosing even finer lattices ($N_t$=16) and we\nwork again with physical quark masses. All these results are confronted with\nthe predictions of the Hadron Resonance Gas model and Chiral Perturbation\nTheory for temperatures below the transition region. Our results can be\nreproduced by using the physical spectrum in these analytic calculations. A\ncomparison with the results of the hotQCD collaboration is also discussed.",
        "positive": "Hadronic Electromagnetic Properties at Finite Lattice Spacing: Electromagnetic properties of the octet mesons as well as the octet and\ndecuplet baryons are augmented in quenched and partially quenched chiral\nperturbation theory to include O(a) corrections due to lattice discretization.\nWe present the results for the SU(3) flavor group in the isospin limit as well\nas the results for SU(2) flavor with non-degenerate quarks. These corrections\nwill be useful for extrapolation of lattice calculations using Wilson valence\nand sea quarks, as well as calculations using Wilson sea quarks and\nGinsparg-Wilson valence quarks."
    },
    {
        "anchor": "Chiral Extrapolation of Hadronic Observables: One of the great challenges of lattice QCD is to produce unambiguous\npredictions for the properties of physical hadrons. We review recent progress\nwith respect to a major barrier to achieving this goal, namely the fact that\ncomputation time currently limits us to large quark mass. Using insights from\nthe study of the lattice data itself, together with the general constraints of\nchiral symmetry, we demonstrate that it is possible to extrapolate accurately\nand in an essentially model independent manner from the mass region where\ncalculations will be performed within the next five years to the chiral limit.",
        "positive": "Spectroscopy of $a_1$ mesons from lattice QCD with the truncated overlap\n  fermions: We study the ground state and next radial excitation of the $a_1$ mesons from\na quenched lattice QCD simulation with the truncated overlap fermions formalism\nbased on domain wall fermions. Our results are consistent with the experimental\nvalues for $a_1$(1260) and $a_1$(1640)."
    },
    {
        "anchor": "Towards the continuum limit with improved Wilson fermions employing open\n  boundary conditions: We present selected results obtained by RQCD from simulations of $N_f=2+1$\nflavours of non-perturbatively $\\mathcal{O}(a)$ improved Wilson fermions,\nemploying open boundary conditions in time. The ensembles were created within\nthe CLS (Coordinated Lattice Simulations) effort at five different values of\nthe lattice spacing, ranging from 0.085fm down to below 0.04fm. Many quark mass\ncombinations were realized, in particular along lines where the sum of the bare\nquark masses was kept fixed as well as trajectories of an approximately\nphysical renormalized strange quark mass. Several key observables, including\nmeson and baryon masses and the axial charge of the nucleon have been computed,\nand preliminary results are presented here. In some cases an accurate and\ncontrolled extrapolation to the continuum limit has become possible.",
        "positive": "Critical Exponents of the 3D Ising Universality Class From Finite Size\n  Scaling With Standard and Improved Actions: We propose a method to obtain an improved Hamiltonian (action) for the Ising\nuniversality class in three dimensions. The improved Hamiltonian has suppressed\nleading corrections to scaling. It is obtained by tuning models with two\ncoupling constants. We studied three different models: the +1,-1 Ising model\nwith nearest neighbour and body diagonal interaction, the spin-1 model with\nstates 0,+1,-1, and nearest neighbour interaction, and phi**4-theory on the\nlattice (Landau-Ginzburg Hamiltonian). The remarkable finite size scaling\nproperties of the suitably tuned spin-1 model are compared in detail with those\nof the standard Ising model. Great care is taken to estimate the systematic\nerrors from residual corrections to scaling. Our best estimates for the\ncritical exponents are nu= 0.6298(5) and eta= 0.0366(8), where the given error\nestimates take into account the statistical and systematic uncertainties."
    },
    {
        "anchor": "Unquenched domain wall quarks with TSMB: The numerical simulation of domain wall quarks with the two-step multi-boson\n(TSMB) algorithm is investigated.\n  Tests are performed on a 8^3*4 lattice with N_f=2 quark flavours.",
        "positive": "Further Evidence For Zero Crossing On The Three Gluon Vertex: The three gluon one particle irreducible function is investigated using\nlattice QCD simulations over a large region of momentum in the Landau gauge for\nfour dimensional pure Yang-Mills equations and the SU(3) gauge group. The\nresults favor a zero crossing of the gluon form factor for momenta in the range\n$220 - 260$ MeV. This zero crossing is required to happen in order to have a\nproperly defined set of Dyson-Schwinger equations. It is also shown that in the\nhigh momentum region the lattice results are compatible with the predictions of\nrenormalisation group improved perturbation theory."
    },
    {
        "anchor": "The Universlity Class of Monopole Condensation in Non-Compact, Quenched\n  Lattice QED: Finite size scaling studies of monopole condensation in noncompact quenched\nlattice $QED$ indicate an authentic second order phase transition lying in the\nuniversality class of four dimensional percolation. Since the upper critical\ndimension of percolation is six, the measured critical indices are far from\nmean-field values. We propose a simple set of ratios as the exact critical\nindices for this transition. The implication of these results for critical\npoints in Abelian gauge theories are discussed.",
        "positive": "Confinement, the Abelian Decomposition, and the Contribution of Topology\n  to the Static Quark Potential: In the past few years, we have presented a new way of considering quark\nconfinement. Through a careful choice of a Cho-Duan-Ge Abelian Decomposition,\nwe can construct the QCD Wilson Loop in terms of an Abelian restricted field.\nThe relationship between the QCD and restricted string tensions is exact; and\nwe do not need to gauge fix, apply any path ordering of gauge links, or\nadditional path integrals. This hints at why mesons are colour neutral.\n  Furthermore, the Abelian restricted field contains two parts: a Maxwell term,\nand a topological term. The topological term can describe magnetic monopoles\nand other topological objects, which can be studied both numerically and\ntheoretically. By examining the topological part of the restricted field\nstrength we have found evidence suggesting that these objects, which will\ncontribute to confinement if present, are indeed there.\n  Previous studies have used simplifications, breaking the exact relationship\nbetween the restricted and QCD string tensions, but it was found that the\ntopological term dominated the restricted string tension. Here we remove those\nsimplifications, and show that the Abelian restricted field does indeed fully\nexplain confinement. However, our results for how much of the restricted string\ntension arises from the topological objects show strong dependence on the\nlattice spacing and level of smearing, so we are not yet able to draw a\ndefinitive conclusion."
    },
    {
        "anchor": "Prospects for a lattice calculation of the rare decay $\u03a3^+\\to\n  p\\ell^+\\ell^-$: We present a strategy for calculating the rare decay of a $\\Sigma^+ (uus)$\nbaryon to a proton $(uud)$ and di-lepton pair using lattice QCD. To determine\nthis observable one needs to numerically evaluate baryonic two-, three-, and\nfour-point correlation functions related to the target process. In particular,\nthe four-point function arises from the insertion of incoming and outgoing\nbaryons, together with a weak Hamiltonian mediating the $s \\to d$ transition\nand an electromagnetic current creating the outgoing leptons. As is described\nin previous work in other contexts, this four-point function has a highly\nnon-trivial relation to the physical observable, due to nucleon and\nnucleon-pion intermediate states. These lead to growing Euclidean time\ndependence and, in the case of the nucleon-pion states, to power-like volume\neffects. We discuss how to treat these issues in the context of the\n$\\Sigma^+\\rightarrow p\\ell^+\\ell^-$ decay and, in particular, detail the\nrelation between the finite-volume estimator and the physical, complex-valued\namplitude. In doing so, we also make connections between various approaches in\nthe literature.",
        "positive": "Decay rates of various bottomonium systems: Using the Bodwin--Braaten--Lepage factorization theorem in heavy quarkonium\ndecay and production processes, we calculated matrix elements associated with\nS- and P-wave bottomonium decays via lattice QCD simulation methods. In this\nwork, we report preliminary results on the operator matching between the\nlattice expression and the continuum expression at one loop level.\nPhenomenological implications are discussed using these preliminary\n\\(\\overline{MS}\\) matrix elements."
    },
    {
        "anchor": "Revisiting symmetries of lattice fermions via spin-flavor representation: Employing the spin-flavor representation, we investigate the structures of\nthe doubler-mixing symmetries and the mechanisms of their spontaneous breakdown\nin four types of lattice fermion formulation. We first revisit the\n$U(4)\\timesU(4)A$ symmetries of the naive fermion with the vanishing bare mass\nm, and re-express them in terms of the spin-flavor representation. We apply the\nsame method to the Wilson fermion, which possesses only the U(1) vector\nsymmetry for general values of m. For a special value of m, however, there\nemerges an additional U(1) symmetry to be broken by pion condensation. We also\nexplore two types of minimally doubled fermion, and discover a similar kind of\nsymmetry enhancement and its spontaneous breakdown.",
        "positive": "The interplay of the sign problem and the infinite volume limit: gauge\n  theories with a theta term: QCD and related gauge theories have a sign problem when a $\\theta$-term is\nincluded; this complicates the extraction of physical information from\nEuclidean space calculations as one would do in lattice studies. The sign\nproblem arises in this system because the partition function for configurations\nwith fixed topological charge $Q$, $\\mathcal{Z}_Q$, are summed weighted by\n$\\exp(i Q \\theta)$ to obtain the partition function for fixed $\\theta$, $\n\\mathcal{Z}(\\theta)$. The sign problem gets exponentially worse numerically as\nthe space-time volume is increased. Here it is shown that apart from the\npractical numerical issues associated with large volumes, there are some\ninteresting issues of principle. A key quantity is the energy density as a\nfunction of $\\theta$, $\\varepsilon(\\theta) = -\\log \\left( \\mathcal{Z}(\\theta)\n\\right )/V$. This is expected to be well defined in the large 4-volume limit.\nSimilarly, one expects the energy density for a fixed topological density\n$\\tilde{\\varepsilon}(Q/V) = -\\log \\left(\\mathcal{Z}_Q \\right )/V$ to be well\ndefined in the limit of large 4-volumes. Intuitively, one might expect that if\none had the infinite volume expression for $\\tilde{\\varepsilon}(Q/V)$ to\narbitrary accuracy, that one could reconstruct $\\varepsilon(\\theta)$ by\ndirectly summing over the topological sectors of the partition function. We\nshow here that there are circumstances where this is not the case. In\nparticular, this occurs in regions where the curvature of $\\varepsilon(\\theta)$\nis negative."
    },
    {
        "anchor": "The phase structure of lattice QCD with two flavours of Wilson quarks\n  and renormalization group improved gluons: The effect of changing the lattice action for the gluon field on the recently\nobserved [1] first order phase transition near zero quark mass is investigated\nby replacing the Wilson plaquette action by the DBW2 action. The lattice action\nfor quarks is unchanged: it is in both cases the original Wilson action. It\nturns out that Wilson fermions with the DBW2 gauge action have a phase\nstructure where the minimal pion mass and the jump of the average plaquette are\ndecreased, when compared to Wilson fermions with Wilson plaquette action at\nsimilar values of the lattice spacing. Taking the DBW2 gauge action is\nadvantageous also from the point of view of the computational costs of\nnumerical simulations.",
        "positive": "Abelian monopoles of the Dirac type and color confinement in QCD: We present results of $SU(3)$ Monte-Carlo studies of a new color confinement\nscheme due to Abelian-like monopoles of the Dirac type without any\ngauge-fixing. We get (1) perfect Abelian dominance with respect to the static\npotentials on $12^4\\sim 16^4$ lattice at $\\beta=5.6-5.8$ using the multilevel\nmethod, (2) monopole as well as Abelian dominances with respect to the static\npotentials by evaluating Polyakov loop correlators on $24^3\\times4$ lattice at\n$\\beta=5.6$. (3) Abelian dual Meissner effects are studied directly by\nmeasuring Abelian color fields and monopole currents around the static source.\nThe vacuum in pure $SU(3)$ seems to be of the type 1 near the border between\nboth types, although scaling is not studied yet."
    },
    {
        "anchor": "General bounds on the Wilson-Dirac operator: Lower bounds on the magnitude of the spectrum of the Hermitian Wilson-Dirac\noperator H(m) have previously been derived for 0<m<2 when the lattice gauge\nfield satisfies a certain smoothness condition. In this paper lower bounds are\nderived for 2p-2<m<2p for general p=1,2,...,d where d is the spacetime\ndimension. The bounds can alternatively be viewed as localisation bounds on the\nreal spectrum of the usual Wilson-Dirac operator. They are needed for the\nrigorous evaluation of the classical continuum limit of the axial anomaly and\nindex of the overlap Dirac operator at general values of m, and provide\ninformation on the topological phase structure of overlap fermions. They are\nalso useful for understanding the instanton size-dependence of the real\nspectrum of the Wilson-Dirac operator in an instanton background.",
        "positive": "Spectral density of the Dirac operator in two-flavour QCD: We compute the spectral density of the (Hermitean) Dirac operator in Quantum\nChromodynamics with two light degenerate quarks near the origin. We use\nCLS/ALPHA lattices generated with two flavours of O(a)-improved Wilson fermions\ncorresponding to pseudoscalar meson masses down to 190 MeV, and with spacings\nin the range 0.05-0.08 fm. Thanks to the coverage of parameter space, we can\nextrapolate our data to the chiral and continuum limits with confidence. The\nresults show that the spectral density at the origin is non-zero because the\nlow modes of the Dirac operator do condense as expected in the Banks-Casher\nmechanism. Within errors, the spectral density turns out to be a constant\nfunction up to eigenvalues of approximately 80 MeV. Its value agrees with the\none extracted from the Gell-Mann-Oakes-Renner relation."
    },
    {
        "anchor": "A test of the Kugo-Ojima confinement criterion by lattice Landau gauge\n  QCD simulations: The first test of the Kugo-Ojima colour confinement criterion by the lattice\nLandau gauge QCD simulation is performed. The parameter u which is expected to\nbe -1\\delta^a_b in the continuum theory was found to be -0.7\\delta^a_b in the\nstrong coupling region. The data is analyzed in connection with the theory of\nZwanziger. In the weak coupling region, the expectation value of the horizon\nfunction is negative or consistent to 0.",
        "positive": "Towards a Topological Mechanism of Quark Confinement: We report on new analyses of the topological and chiral vacuum structure of\nfour-dimensional QCD on the lattice. Correlation functions as well as\nvisualization of monopole currents in the maximally Abelian gauge emphasize\ntheir topological origin and gauge invariant characterization. The\n(anti)selfdual character of strong vacuum fluctuations is reveiled by\nsmoothing. In full QCD, (anti)instanton positions are also centers of the local\nchiral condensate and quark charge density. Most results turn out generically\nindependent of the action and the cooling/smoothing method."
    },
    {
        "anchor": "$B\\to\u03c0\\ell\u03bd$ semileptonic form factors from unquenched lattice QCD\n  and determination of $|V_{ub}|$: We compute the $B\\to\\pi\\ell\\nu$ semileptonic form factors and update the\ndetermination of the CKM matrix element $|V_{ub}|$. We use the MILC asqtad\nensembles with $N_f=2+1$ sea quarks at four different lattice spacings in the\nrange $a \\approx 0.045$~fm to $0.12$~fm. The lattice form factors are\nextrapolated to the continuum limit using SU(2) staggered chiral perturbation\ntheory in the hard pion limit, followed by an extrapolation in $q^2$ to the\nfull kinematic range using a functional $z$-parameterization. The extrapolation\nis combined with the experimental measurements of the partial branching\nfraction to extract $|V_{ub}|$. Our preliminary result is $|V_{ub}|=(3.72\\pm\n0.14)\\times 10^{-3}$, where the error reflects both the lattice and\nexperimental uncertainties, which are now on par with each other.",
        "positive": "Investigating corrections to a Gaussian distribution of the complex\n  phase: It has been suggested that the density of states approach to performing\nlattice simulations in QCD with nonzero chemical potential can be modified to\nimprove the signal to noise ratio by performing a cumulant expansion of the\ncomplex phase of the fermion determinant, and then simplified by truncating the\nexpansion after the first non-zero cumulant. This truncation corresponds to\napproximating the distribution of the complex phase of the fermion determinant\nby a Gaussian form. The crucial question is: how large are the other cumulants?\nWe calculate the distribution of the complex phase from the hadron resonance\ngas model and from a combined lattice strong coupling and hopping expansion. In\nthe case of the hadron resonance gas model the distribution takes a Gaussian\nform, but from the strong coupling and hopping expansion there are corrections.\nWe discuss the implications to lattice simulations."
    },
    {
        "anchor": "New extended interpolating fields built from three-dimensional fermions: New extended interpolating operators made of quenched three dimensional\nfermions are introduced in the context of lattice QCD. The mass of the 3D\nfermions can be tuned in a controlled way to find a better overlap of the\nextended operators with the states of interest. The extended operators have\ngood renormalization properties and are easy to control when taking the\ncontinuum limit. Moreover the short distance behaviour of the two point\nfunctions built from these operators is greatly improved. A numerical\ncomparison with point sources and Jacobi smeared sources on dynamical 2+1\nflavour configurations is presented.",
        "positive": "A Ginsparg-Wilson approach to lattice CP symmetry, Weyl and Majoranna\n  fermions, and the Higgs mechanism: Recently, two solutions have been proposed to the long standing problem of\n$\\mathcal{CP}$-symmetry on the lattice, which is particularly evident when\nconsidering the construction of chiral gauge theories. The first, based on a\nlattice modification of $\\mathcal{CP}$ was presented by Igarashi and Pawlowski;\nthe second by myself using the renormalisation group and Ginsparg-Wilson\nrelation. In this work, I combine the two approaches and show that they are\neach part of a more general framework related to an underlying renormalisation\ngroup. I continue by formulating Weyl and Majorana fermions on the lattice, and\ndiscussing applications to the fermion propagator in the presence of the Higgs\nfield."
    },
    {
        "anchor": "Partially Quenched Chiral Perturbation Theory and the Replica Method: We describe a novel framework for partially quenched chiral perturbation\ntheory based on the replica method. The computational rules are exceedingly\nsimple. We illustrate these rules by computing the partially quenched chiral\ncondensate to one-loop order. By considering arbitrary chiral $k$-point\nfunctions we show explicitly to one-loop order the equivalence between this\nmethod and the one based on supersymmetry. It is possible to go smoothly from\nthe conventional replica method to a supersymmetric variant by choosing the\nnumber of valence quarks to be negative.",
        "positive": "Variational Approach to Real-Time Evolution of Yang-Mills Gauge Fields\n  on a Lattice: Applying a variational method to a Gaussian wave ansatz, we have derived a\nset of semi-classical evolution equations for SU(2) lattice gauge fields, which\ntake the classical form in the limit of a vanishing width of the Gaussian wave\npacket. These equations are used to study the quantum effects on the classical\nevolutions of the lattice gauge fields."
    },
    {
        "anchor": "Exact Matching Condition for Matrix Elements in Lattice and\n  $\\overline{MS}$ Schemes: The exact matching condition is given for hadron matrix elements calculated\nin any two different schemes, in particular, in the lattice and dimensional\nregularization, (modified) minimal subtraction $\\overline{\\rm MS}$ schemes. The\nresult provides insight into and permits to go beyond Lepage and Mackenzie's\nmean field theory of removing tadpole contributions in lattice operators.",
        "positive": "The Geometry of the Elongated Phase in 4-D Simplicial Quantum Gravity: We discuss the elongated phase of 4D simplicial quantum gravity by exploiting\nrecent analytical results. In particular using Walkup's theorem we prove that\nthe dominating configurations in the elongated phase are tree-like structures\ncalled \"stacked spheres\". Such configurations can be mapped into branched\npolymers and baby universes arguments are used in order to analyse the critical\nbehaviour of theory in the weak coupling regime."
    },
    {
        "anchor": "Fisher zeros and conformality in lattice models: Fisher zeros are the zeros of the partition function in the complex\nbeta=2N_c/g^2 plane. When they pinch the real axis, finite size scaling allows\none to distinguish between first and second order transition and to estimate\nexponents. On the other hand, a gap signals confinement and the method can be\nused to explore the boundary of the conformal window. We present recent\nnumerical results for 2D O(N) sigma models, 4D U(1) and SU(2) pure gauge and\nSU(3) gauge theory with N_f=4 and 12 flavors. We discuss attempts to understand\nsome of these results using analytical methods. We discuss the 2-lattice\nmatching and qualitative aspects of the renormalization group (RG) flows in the\nMigdal-Kadanoff approximation, in particular how RG flows starting at large\nbeta seem to move around regions where bulk transitions occur. We consider the\neffects of the boundary conditions on the nonperturbative part of the average\nenergy and on the Fisher zeros for the 1D O(2) model.",
        "positive": "Sea quark QED effects and twisted mass fermions: We show that maximally twisted mass fermions can be employed to regularize on\nthe lattice the fully unquenched QCD+QED theory with vanishing $\\theta$-term.\nWe discuss how the critical mass of the up and down quarks can be conveniently\ndetermined beyond the electroquenched approximation by imposing that certain\nsymmetries of continuum QCD+QED, which are broken by Wilson terms, get restored\nin the continuum limit. A mixed action setup is outlined that allows to extend\nbeyond the electroquenched approximation the computation (with only O($a^2$)\nartifacts) of the leading isospin breaking corrections to physical observables\nusing the RM123 method and (pure QCD) ETMC gauge ensembles with $N_f=2+1+1$\ndynamical quark flavours."
    },
    {
        "anchor": "Chiral structure of the solutions of the Ginsparg-Wilson relation: We analyse the structure of solutions of the Ginsparg-Wilson relation for\nlattice Dirac operator in topologically trivial gauge sector. We show that the\nproperties of such solutions relating to the perturbative stability of the pole\nof the fermion propagator as well as to the structure of the Yukawa models\nbased on these solutions are solely determined by the non-local chirally\ninvariant part of these Dirac operators. Depending on the structure of this\npart, the pole in the fermion propagator may or may not be stable under\nradiative corrections. We illustrate this by explicit examples.",
        "positive": "Attractive $N$-$\u03c6$ Interaction and Two-Pion Tail from Lattice QCD\n  near Physical Point: First results on the interaction between the $\\phi$-meson and the nucleon\n($N$) are presented based on the ($2+1$)-flavor lattice QCD simulations with\nnearly physical quark masses. Using the HAL QCD method, the spacetime\ncorrelation of the $N$-$\\phi$ system in the spin 3/2 channel is converted into\nthe $N$-$\\phi$ scattering phase shift through the interaction potential. The\n$N$-$\\phi$ potential appears to be a combination of a short-range attractive\ncore and a long-range attractive tail. The latter is found to be consistent\nwith the two-pion exchange (TPE) obtained from the interaction between a\ncolor-dipole and the nucleon. The resultant scattering length and effective\nrange for $m_{\\pi}=$ 146.4 MeV are $ a^{(3/2)}_0=-1.43(23)_{\\rm\nstat.}\\left(^{+36}_{-06}\\right)_{\\rm syst.} {\\rm fm}$ and $ r^{(3/2)}_{\\rm\neff}=2.36(10)_{\\rm stat.}\\left(^{+02}_{-48}\\right)_{\\rm syst.} {\\rm fm}$,\nrespectively. The magnitude of the scattering length is shown to have\nnontrivial dependence of $m_{\\pi}$ and is sensitive to the existence of the\nlong-range tail from TPE."
    },
    {
        "anchor": "Renormalized quasi parton distribution function of pion: We present preliminary numerical results on the connected piece of the\nquasi-PDF of pion as determined using Wilson-Clover valence fermions on HISQ\nensembles. We discuss its non-perturbative renormalization in RI/MOM scheme\nwith and without removal of the divergent self-energy part, and compare its\nrunning with expectation from perturbation theory. We also discuss the matching\nof pion QPDF to PDF, and various systematic effects associated with it.",
        "positive": "A (P)HMC algorithm for N_f = 2 + 1 + 1 flavours of twisted mass fermions: We present a detailed design of a (P)HMC simulation algorithm for N_f = 2 + 1\n+ 1 maximally twisted Wilson quark flavours. The algorithm retains even/odd and\nmass-shift preconditionings combined with multiple Molecular Dynamics time\nscales for both the light mass degenerate, u and d, quarks and the heavy mass\nnon-degenerate, s and c, quarks. Various non-standard aspects of the algorithm\nare discussed, among which those connected to the use of a polynomial\napproximation for the inverse (square root of the squared) Dirac matrix in the\ns and c quark sector."
    },
    {
        "anchor": "Spectroscopy of $Sp(4)$ lattice gauge theory with $n_f=3$ antisymmetric\n  fermions: We perform numerical calculations of masses and decay constants of the\nlightest (flavoured) pseudoscalar, vector and axial vector mesons in the\n$Sp(4)$ lattice gauge theory with three Dirac fermions in the antisymmetric\nrepresentation. The corresponding continuum theory plays an important role in\ncertain ultra-violet complete realisations of composite Higgs, partial top\ncompositeness, and composite dark matter models. In addition, we measure the\nmasses of other flavoured mesons in spin-$0$ and $1$ channels, as well as the\nfirst excited state of the vector mesons. Using the gradient flow to set the\nscale, we carry out the continuum extrapolation and show preliminary results\nfor the meson spectrum of the theory.",
        "positive": "Correlations of Abelian monopoles in quark-gluon plasma: In this paper the properties of thermal Abelian monopoles in the\ndeconfinement phase of the SU(2) gluodynamics are considered. In particular, to\nstudy the properties of the Abelian monopole component of QGP we calculate\nthree-point correlation functions of monopoles for different temperatures from\nthe region $T/T_c \\in (1.5, 6.8)$. The results of the calculation show that the\nthree-point correlation functions can be described by independent pair\ncorrelations of monopoles. From this one can conclude that the system of\nAbelian monopoles in QGP reveals the properties of a dilute gas. In addition,\none can assert that the interaction between Abelian monopoles is a pair\ninteraction and there are no three-particle forces acting between monopoles."
    },
    {
        "anchor": "Improving the sign problem in QCD at finite density: If the fermion mass is large enough, the phase of the fermion determinant of\nQCD at finite density is strongly correlated with the imaginary part of the\nPolyakov loop. This fact can be exploited to reduce the fluctuations of the\nphase significantly, making numerical simulations feasible in regions of\nparameters where the naive brute force method does not work.",
        "positive": "Four-Dimensional N=1 Supersymmetric Yang-Mills Theory on the Lattice\n  without Fine-Tuning: We propose a method to formulate four-dimensional N=1 super Yang-Mills theory\non the lattice without fine-tuning. We first show that four-dimensional Weyl\nfermion in a real representation, which is equivalent to Majorana fermion, can\nbe formulated using the domain wall approach with an addition of a Majorana\nmass term only for the unwanted mirror fermion. This formalism has manifest\ngauge invariance. Fermion number conservation is violated only by the\nadditional Majorana mass term for the mirror fermion and the violation is\npropagated to the physical fermion sector through anomalous currents. Due to\nthis feature, the formalism, when applied to the gluino in the present case,\nensures the restoration of supersymmetry in the continuum limit without\nfine-tuning, unlike the proposal by Curci and Veneziano."
    },
    {
        "anchor": "Excitation Spectra in a Heavy-Light Meson-Meson System: A system of two static quarks, at fixed distances r, and two light quarks is\nstudied on an anisotropic lattice. Excitations by operators emphasizing quark\nor gluon degrees of freedom are examined. The maximum entropy method is applied\nin the spectral analysis. These simulations ultimately aim at learning about\nmechanisms of hadronic interaction.",
        "positive": "Complex Langevin simulations and the QCD phase diagram: Recent\n  developments: In this review we present the current state-of-the-art on complex Langevin\nsimulations and their implications for the QCD phase diagram. After a short\nsummary of the complex Langevin method, we present and discuss recent\ndevelopments. Here we focus on the explicit computation of boundary terms,\nwhich provide an observable that can be used to check one of the criteria of\ncorrectness explicitly. We also present the method of Dynamic Stabilization and\nelaborate on recent results for fully dynamical QCD."
    },
    {
        "anchor": "Model-independent determination of the nucleon charge radius from\n  lattice QCD: Lattice QCD calculations of nucleon form factors are restricted to discrete\nvalues of the Euclidean four-momentum transfer. Therefore, the extraction of\nradii typically relies on parametrizing and fitting the lattice QCD data to\nobtain its slope close to zero momentum transfer. We investigate a new method,\nwhich allows to compute the nucleon radius directly from existing lattice QCD\ndata, without assuming a functional form for the momentum dependence of the\nunderlying form factor. The method is illustrated for the case of the isovector\nmean square charge radius of the nucleon $\\langle r^2_\\mathrm{isov} \\rangle$\nand the quark-connected contributions to $\\langle r^2_p\\rangle$ and $\\langle\nr^2_n \\rangle$ for the proton and neutron, respectively. Computations are\nperformed using a single gauge ensemble with $N_f=2+1+1$ maximally twisted mass\nclover-improved fermions at physical quark mass and a lattice spacing of\n$a=0.08\\mathrm{fm}$.",
        "positive": "Update: Precision D_s decay constant from full lattice QCD using very\n  fine lattices: We update our previous determination of both the decay constant and the mass\nof the $D_s$ meson using the Highly Improved Staggered Quark formalism. We\ninclude additional results at two finer values of the lattice spacing along\nwith improved determinations of the lattice spacing and improved tuning of the\ncharm and strange quark masses. We obtain $m_{D_s}$ = 1.9691(32) GeV, in good\nagreement with experiment, and $f_{D_s}$ = 0.2480(25) GeV. Our result for\n$f_{D_s}$ is 1.6$\\sigma$ lower than the most recent experimental average\ndetermined from the $D_s$ leptonic decay rate and using $V_{cs}$ from CKM\nunitarity. Combining our $f_{D_s}$ with the experimental rate we obtain a\ndirect determination of $V_{cs} = 1.010(22)$, or alternatively $0.990 {+0.013\n\\atop -0.016}$ using a probability distribution for statistical errors for this\nquantity which vanishes above 1. We also include an accurate prediction of the\ndecay constant of the $\\eta_c$, $f_{\\eta_c}$ = 0.3947(24) GeV, as a calibration\npoint for other lattice calculations."
    },
    {
        "anchor": "Renormalization of bilinear and four-fermion operators through temporal\n  moments: We propose a renormalization scheme that can be simply implemented on the\nlattice. It consists of the temporal moments of two-point and three-point\nfunctions calculated with finite valence quark mass. The scheme is confirmed to\nyield a consistent result with another renormalization scheme in the continuum\nlimit for the bilinear operators. We apply a similar renormalization scheme for\nthe non-perturbative renormalization of four-fermion operators appearing in the\nweak effective Hamiltonian.",
        "positive": "Classical improvement of lattice actions and quantum effects: a unified\n  view: The possibility of removing the one-loop perturbative effects of lattice\nartifacts by a proper choice of the lattice action is explored, and found to\ndepend crucially on the properties of the physical quantity considered. In this\nrespect the finite-space-volume mass gap m(L) is an improved observable. We\nfind an explicit momentum space representation of the one-loop contribution to\nm(L) for arbitrary lattice actions in the case of two-dimensional O(N) sigma\nmodels. We define a ``tree perfect'' Symanzik action and find that it formally\nremoves all one-loop lattice artifacts in m(L). On-shell improved actions do\nnot share this property."
    },
    {
        "anchor": "Simulating $\\mathbb{Z}_2$ lattice gauge theory on a quantum computer: The utility of quantum computers for simulating lattice gauge theories is\ncurrently limited by the noisiness of the physical hardware. Various quantum\nerror mitigation strategies exist to reduce the statistical and systematic\nuncertainties in quantum simulations via improved algorithms and analysis\nstrategies. We perform quantum simulations of $1+1d$ $\\mathbb{Z}_2$ gauge\ntheory with matter to study the efficacy and interplay of different error\nmitigation methods: readout error mitigation, randomized compiling, rescaling,\nand dynamical decoupling. We compute Minkowski correlation functions in this\nconfining gauge theory and extract the mass of the lightest spin-1 state from\nfits to their time dependence. Quantum error mitigation extends the range of\ntimes over which our correlation function calculations are accurate by a factor\nof six and is therefore essential for obtaining reliable masses.",
        "positive": "Ab Initio Calculation of Relativistic Corrections to the Static\n  Interquark potential I: SU(2) Gauge Theory: We test the capability of state-of-the-art lattice techniques for a precise\ndetermination of relativistic corrections to the static interquark potential,\nby use of SU(2) gauge theory. Emphasis is put on the short range structure of\nthe spin dependent potentials, with lattice resolution a ranging from a approx\n0.04 fm (at beta=2.74) down to a approx 0.02 fm (at beta=2.96) on volumes of\n32^4 and 48^4 lattice sites. We find a new short range Coulomb-like\ncontribution to the spin-orbit potential V_1'."
    },
    {
        "anchor": "The overlap lattice Dirac operator and dynamical fermions: I show how to avoid a two level nested conjugate gradient procedure in the\ncontext of Hybrid Monte Carlo with the overlap fermionic action. The resulting\nprocedure is quite similar to Hybrid Monte Carlo with domain wall fermions, but\nis more flexible and therefore has some potential worth exploring.",
        "positive": "QCD in the delta-Regime: The delta-regime of QCD is characterised by light quarks in a small spatial\nbox, but a large extent in (Euclidean) time. In this setting a specific variant\nof chiral perturbation theory - the delta-expansion - applies, based on a\nquantum mechanical treatment of the quasi one-dimensional system. In\nparticular, for vanishing quark masses one obtains a residual pion mass M_pi^R,\nwhich has been computed to the third order in the delta-expansion. A comparison\nwith numerical measurements of this residual mass allows for a new\ndetermination of some Low Energy Constants, which appear in the chiral\nLagrangian. We first review the attempts to simulate 2-flavour QCD directly in\nthe delta-regime. This is very tedious, but results compatible with the\npredictions for M_pi^R have been obtained. Then we show that an extrapolation\nof pion masses measured in a larger volume towards the delta-regime leads to\ngood agreement with the theoretical predictions. From those results, we also\nextract a value for the (controversial) sub-leading Low Energy Constant \\bar\nl_3."
    },
    {
        "anchor": "On the Universality Class of Monopole Percolation in Scalar QED: We study the critical properties of the monopole-percolation transition in\nU(1) lattice gauge theory coupled to scalars at infinite ($\\beta=0$) gauge\ncoupling. We find strong scaling corrections in the critical exponents that\nmust be considered by means of an infinite-volume extrapolation. After the\nextrapolation, our results are as precise as the obtained for the four\ndimensional site-percolation and, contrary to previously stated, fully\ncompatible with them.",
        "positive": "Numerical results for gauge theories near the conformal window: A novel strong interaction beyond the standard model could provide a\ndynamical explanation of electroweak symmetry breaking. Experimental results\nstrongly constrain properties of models that realise this mechanism. Whether\nthese constraints are obeyed by any strongly interacting quantum field theory\nis a non-perturbative problem that needs to be addressed by first-principle\ncalculations. Monte Carlo simulations of lattice regularised gauge theories is\na powerful tool that enables us to address this question. Recently various\nlattice investigations have appeared that have studied candidate models of\nstrongly interacting dynamics beyond the standard model. After a brief review\nof the main methods and of some recent results, we focus on the analysis of\nSU(2) gauge theory with one adjoint Dirac fermion flavour, which is shown to\nhave a near-conformal behaviour with an anomalous dimension of order one. The\nimplications of our findings are also discussed."
    },
    {
        "anchor": "Preliminary lattice study of $I=0$ $K \\overline{K}$ scattering: We deliver the realistic ab initio lattice investigations of $K \\overline{K}$\nscattering. In the Asqtad-improved staggered dynamical fermion formulation, we\ncarefully measure $K\\overline{K}$ four-point function in the $I=0$ channel by\nmoving wall sources without gauge fixing, and clearly find an attractive\ninteraction in this channel, which is in agreement with the theoretical\npredictions. An essential ingredient in our lattice calculation is to properly\ntreat the disconnected diagram. Moreover, we explain the difficulties of these\nlattice calculations, and discuss the way to improve the statistics. Our\nlattice investigations are carried out with the MILC $2+1$ gauge configuration\nat lattice spacing $a \\approx 0.15$~fm.",
        "positive": "The QCD deconfinement critical point for $N_\u03c4=8$ with $N_f=2$\n  flavours of unimproved Wilson fermions: QCD at zero baryon density in the limit of infinite quark mass undergoes a\nfirst order deconfinement phase transition at a critical temperature $T_c$\ncorresponding to the breaking of the global centre symmetry. In the presence of\ndynamical quarks this symmetry is explicitly broken. Lowering the quark mass\nthe first order phase transition weakens and terminates in a second order Z(2)\npoint. Beyond this line confined and deconfined regions are analytically\nconnected by a crossover transition. As the continuum limit is approached (i.e.\nthe lattice spacing is decreased) the region of first order transitions expands\ntowards lower masses. We study the deconfinement critical point with standard\nWilson fermions and $N_f=2$ flavours. To this end we simulate several kappa\nvalues on $N_\\tau=8$ and various aspect ratios in order to extrapolate to the\nthermodynamic limit, applying finite size scaling. We estimate if and when a\ncontinuuum extrapolation is possible."
    },
    {
        "anchor": "Z(3) Interfaces in Lattice Gauge Theory: A study is made of properties of the Z(3) interface which forms between the\ndifferent ordered phases of pure SU(3) gauge theory above a critical\ntemperature. The theory is simulated on a (2+1)-D lattice at various\ntemperatures above this critical point. At high temperatures, the interface\ntension is shown to agree well with the prediction of perturbation theory. Near\nthe critical temperature, the interface behaviour is characterised by various\ndisplacement moments, and modelled by an interacting scalar field theory. This\nthesis is provided for reference, as it gives full details of the computational\nand statistical methods outlined only briefly in preprints hep-lat/9605040 and\nhep-lat/9607005.",
        "positive": "Double parton distributions in the nucleon from lattice QCD: We evaluate nucleon four-point functions in the framework of lattice QCD in\norder to extract the first Mellin moment of double parton distributions (DPDs)\nin the unpolarized proton. In this first study, we employ an nf = 2 + 1\nensemble with pseudoscalar masses of mpi = 355 MeV and mK = 441 MeV. The\nresults are converted to the scale mu = 2 GeV. Our calculation includes all\nWick contractions, and for almost all of them a good statistical signal is\nobtained. We analyze the dependence of the DPD Mellin moments on the quark\nflavor and the quark polarization. Furthermore, the validity of frequently used\nfactorization assumptions is investigated."
    },
    {
        "anchor": "Two loop lattice expansion of the Schroedinger functional coupling in\n  improved QCD: The contributions of the improved fermion action of Sheikholeslami and\nWohlert to the two loop coefficient of the expansion of the Schroedinger\nfunctional coupling in terms of the lattice coupling are calculated for the\ngauge group SU(3). These coefficients are required for the second order\nrelation of lattice data to the MSbar-coupling. By taking into account all\nimprovement coefficients we are able to improve the Schroedinger functional to\ntwo loop order.",
        "positive": "Machine learning phases of an Abelian gauge theory: The phase transition of the two-dimensional $U(1)$ quantum link model on the\ntriangular lattice is investigated by employing a supervised neural network\n(NN) consisting of only one input layer, one hidden layer of two neurons, and\none output layer. No information on the studied model is used when the NN\ntraining is conducted. Instead, two artificially made configurations are\nconsidered as the training set. Interestingly, the obtained NN not only\nestimates the critical point accurately but also uncovers the physics\ncorrectly. The results presented here imply that a supervised NN, which has a\nvery simple architecture and is trained without any input from the investigated\nmodel, can identify the targeted phase structure with high precision."
    },
    {
        "anchor": "The light Roberge-Weiss tricritical endpoint at imaginary isospin\n  chemical potential: We discuss results for the Roberge Weiss (RW) phase transition at nonzero\nimaginary baryon and isospin chemical potentials, in the plane of temperature\nand quark masses. Our study focuses on the light tricritical endpoint which has\nalready been used as a starting point for extrapolations aiming at the chiral\nlimit at vanishing chemical potentials. In particular, we are interested in\ndetermining how imaginary isospin chemical potential shifts the tricritical\nmass with respect to earlier studies at zero imaginary isospin chemical\npotential. A positive shift might allow one to perform the chiral\nextrapolations from larger quark mass values, therefore making them less\ncomputationally expensive. We also present results for the dynamics of Polyakov\nloop clusters across the RW phase transition.",
        "positive": "$B \\to K^* \u03b3$: Penguins on the Lattice: We calculate the leading-order matrix element for the decay $B \\to K^*\n\\gamma$ in the quenched approximation of lattice QCD on a $24^3 \\times 48$\nlattice at $\\beta=6.2$, using an O(a)-improved fermion action. Extrapolating\nthe quark masses to their physical values we obtain an on-shell form factor of\n$T_1(q^2=0)=0.15+12-14$, where the errors quoted are purely statistical. We\nfind $T_1$ is approximately independent of the spectator quark mass and extract\n$T_1(q^2=0)=0.15+5-4$ if this independence is assumed. We compare this with the\nsame form factor derived (in the Standard Model) from the CLEO experimental\nbranching ratio of $BR(B \\to K^* \\gamma) = (4.5 \\pm 1.5 \\pm 0.9) \\times\n10^{-5}$ and find the results to be consistent within statistical errors."
    },
    {
        "anchor": "A Two-Parameter Recursion Formula For Scalar Field Theory: We present a two-parameter family of recursion formulas for scalar field\ntheory. The first parameter is the dimension $(D)$. The second parameter\n($\\zeta$) allows one to continuously extrapolate between Wilson's approximate\nrecursion formula and the recursion formula of Dyson's hierarchical model. We\nshow numerically that at fixed $D$, the critical exponent $\\gamma $ depends\ncontinuously on $\\zeta$. We suggest the use of the $\\zeta -$independence as a\nguide to construct improved recursion formulas.",
        "positive": "Perturbative improvement of staggered fermions using fat links: We study possibility of improving staggered fermions using various fat links\nin order to reduce perturbative corrections to the gauge-invariant staggered\nfermion operators. We prove five theorems on SU(3) projection, triviality in\nrenormalization, multiple SU(3) projections, uniqueness and equivalence. As a\nresult of these theorems, we show that, at one loop level, the renormalization\nof staggered fermion operators is identical between SU(3) projected Fat7 links\nand hypercubic links, as long as the action and operators are constructed by\nimposing the same perturbative improvement condition. In addition, we propose a\nnew view of SU(3) projection as a tool of tadpole improvement for the staggered\nfermion doublers. As a conclusion, we present alternative choices of\nconstructing fat links to improve the staggered fermion action and operators,\nwhich deserve further investigation."
    },
    {
        "anchor": "Drastic Reduction of Cutoff Effects in 2-d Lattice O(N) Models: We investigate the cutoff effects in 2-d lattice O(N) models for a variety of\nlattice actions, and we identify a class of very simple actions for which the\nlattice artifacts are extremely small. One action agrees with the standard\naction, except that it constrains neighboring spins to a maximal relative angle\ndelta. We fix delta by demanding that a particular value of the step scaling\nfunction agrees with its continuum result already on a rather coarse lattice.\nRemarkably, the cutoff effects of the entire step scaling function are then\nreduced to the per mille level. This also applies to the theta-vacuum effects\nof the step scaling function in the 2-d O(3) model. The cutoff effects of other\nphysical observables including the renormalized coupling and the mass in the\nisotensor channel are also reduced drastically. Another choice, the mixed\naction, which combines the standard quadratic with an appropriately tuned large\nquartic term, also has extremely small cutoff effects. The size of cutoff\neffects is also investigated analytically in 1-d and at N = infinity in 2-d.",
        "positive": "Good and bad diquark properties and spatial correlations in lattice QCD: We study good, bad and not-even-bad diquarks on the lattice in a\ngauge-invariant formalism in full QCD. We establish their spectral masses with\nshort extrapolations to the physical point, observing agreement with\nphenomenological expectations. We find that only the good diquark has\nattractive quark-quark spatial correlations, with spherical shape and size\n$\\sim0.6$ fm. Our results provide quantitative support for modelling the\nlow-lying baryon spectrum using good light diquark effective degrees of\nfreedom."
    },
    {
        "anchor": "Multicanonical Spin Glass Simulations: We report a Monte Carlo simulation of the $2D$ Edwards-Anderson spin glass\nmodel within the recently introduced multicanonical ensemble. Replica on\nlattices of size $L^2$ up to $L=48$ are investigated. Once a true groundstate\nis found, we are able to give a lower bound on the number of statistically\nindependent groundstates sampled. Temperature dependence of the energy, entropy\nand other quantities of interest are easily calculable. In particular we report\nthe groundstate results. Computations involving the spin glass order parameter\nare more tedious. Our data indicate that the large $L$ increase of the\nergodicity time is reduced to an approximately $V^3$ power law. Altogether the\nresults suggest that the multicanonical ensemble improves the situation of\nsimulations for spin glasses and other systems which have to cope with similar\nproblems of conflicting constraints.",
        "positive": "Gluonic-Excitation Energies and Abelian Dominance in SU(3) QCD: We present the first study of the Abelian-projected gluonic-excitation\nenergies for the static quark-antiquark (Q$\\bar{\\rm Q}$) system in SU(3)\nlattice QCD at the quenched level, using a $32^4$ lattice at $\\beta = 6.0$. We\ninvestigate ground-state and three excited-state Q$\\bar{\\rm Q}$ potentials,\nusing smeared link variables on the lattice. We find universal Abelian\ndominance for the quark confinement force of the excited-state Q$\\bar{\\rm Q}$\npotentials as well as the ground-state potential. Remarkably, in spite of the\nexcitation phenomenon in QCD, we find Abelian dominance for the first\ngluonic-excitation energy of about 1 GeV at long distances in the maximally\nAbelian gauge. On the other hand, no Abelian dominance is observed for higher\ngluonic-excitation energies even at long distances. This suggests that there is\nsome threshold between 1 and 2 GeV for the applicable excitation-energy region\nof Abelian dominance. Also, we find that Abelian projection significantly\nreduces the short-distance $1/r$-like behavior in gluonic-excitation energies."
    },
    {
        "anchor": "Cutoff effects of the gradient flow for fermions: I analyze cutoff effects of the gradient flow for Wilson-type fermions. I\nshow that with a proper choice of the higher dimensional fields in the Symanzik\neffective theory, O($a$) improvement of the action is achieved changing the\ninitial conditions of the gradient flow equation.",
        "positive": "Domain wall fermions at finite temperature: We investigate the properties of domain wall fermions on a set of quenched\nconfigurations at non-zero temperature. In particular, we compute the low lying\neigenvalues of the DWF operator and study their relation with topology, level\ncrossings and chiral symmetry breaking. We also measure the screening\ncorrelators and discuss the dependence on the extent of the extra dimension and\nthe quark mass."
    },
    {
        "anchor": "Center regions as a solution to the Gribov problem of the center vortex\n  model: The center vortex model, capable of explaining confinement and chiral\nsymmetry breaking, has been plagued by the lattice equivalent of Gribov copies:\ndifferent maxima of the gauge functional lead to different predictions of the\nstring tension. It is possible to resolve this problem using center regions,\nloops evaluating to center elements, as guide for the gauge fixing procedure.\nThe success of this approach was already shown, but the algorithms came with an\narbitrary free parameter. In recent development this parameter has been fixed,\neven improving the results.",
        "positive": "Restoring chiral symmetry to O(a^2) for dynamical Wilson fermions: We present results for the non-perturbative determination of the improvement\nand renormalization factors of the isovector axial current for lattice QCD with\ntwo flavors of dynamical Wilson quarks. The improvement and normalization\nconditions are formulated in terms of matrix elements of the PCAC relation in\nthe Schroedinger functional setup and results are given in the form of\ninterpolating formulae for bare gauge couplings beta=6/g_0^2>5.2."
    },
    {
        "anchor": "$K_{l3}$ form factors in $N_f = 2+1$ QCD at physical point on large\n  volume: We present our results of the $K_{l3}$ form factors on the volume whose\nspatial extent is more than $L=$10 fm, with the physical pion and kaon masses\nusing the stout-smearing clover $N_f = 2+1$ quark action and Iwasaki gauge\naction at $a^{-1}\\approx2.3$ GeV. The $K_{l3}$ form factor at zero momentum\ntransfer is obtained from fit based on the next-to-leading (NLO) formula in\nSU(3) chiral perturbation theory. We estimate systematic errors of the form\nfactor, mainly coming from the finite lattice spacing effect. We also determine\nthe value of $|V_{us}|$ by combining our result with the experiment and check\nthe consistency with the standard model prediction. The result is compared with\nthe previous lattice calculations.",
        "positive": "Hadron spectroscopy from lattice QCD: I present recent developments in the lattice QCD calculations of the light\nhadron spectrum. Emphasis is placed on the limitation of the quenched\napproximation in reproducing the observed spectrum and indications that the\ndiscrepancy is reduced by introducing two flavors of light dynamical quarks."
    },
    {
        "anchor": "Simulations of supersymmetric Yang-Mills theory: Results of a numerical simulation concerning the low-lying spectrum of\nfour-dimensional N=1 SU(2) Supersymmetric Yang-Mills (SYM) theory on the\nlattice with light dynamical gluinos are reported. We use the tree-level\nSymanzik improved gauge action and Wilson fermions with stout smearing of the\ngauge links in the Wilson-Dirac operator. The configurations are produced with\nthe Two-Step Polynomial Hybrid Monte Carlo (TS-PHMC) algorithm. We performed\nsimulations on lattices up to a size of 24^3x48 at \\beta=1.6. Using QCD units\nwith the Sommer scale being set to r_0=0.5 fm, the lattice spacing is about\na~0.09 fm, and the spatial extent of the lattice corresponds to 2.1 fm to\ncontrol finite size effects. At the lightest simulated gluino mass our results\nindicate a mass for the lightest gluino-glue bound state, which is considerably\nheavier than the values obtained for its possible superpartners. Whether\nsupermultiplets are formed remains to be studied in upcoming simulations.",
        "positive": "Coupled-channel $\u039b_{c}K^{+}-pD_{s}$ Interaction in Flavor $\n  \\textrm{SU}\\left(3\\right) $ Limit of Lattice QCD: We study $S$-wave interactions in the\n$I\\left(J^{p}\\right)=1/2\\left(1/2^{-}\\right)$ $\\Lambda_{c}K^{+}-pD_{s}$ system\non the basis of the coupled-channel HAL QCD method. The potentials which are\nfaithful to QCD S-matrix below the $ pD^{*} $ threshold are extracted from\nNambu-Bethe-Salpeter wave functions on the lattice in Flavor $\n\\textrm{SU}\\left(3\\right) $ Limit. For the simulation, we employ $ 3 $-flavor\nfull QCD gauge configurations on a $\\left(1.93 \\:\\textrm{fm} \\right)^{3}$\nvolume at $m_{\\pi}\\simeq 872$ MeV. %\\textcolor{red}{For the charm quark, the\nrelativistic heavy quark action is employed to treat its dynamics on the\nlattice}.\n  We present our results of the S-wave coupled-channel potentials for the\n$\\Lambda_{c}K^{+}-pD_{s}$ system in the $1/2\\left(1/2^{-}\\right)$ state as well\nas scattering observables obtained from the extracted potential matrix. We\nobserve that the coupling between $\\Lambda_{c}K^{+}$ and $pD_{s}$ channels is\nweak. The phase shifts and scattering length obtained from the extracted\npotential matrix show that the $\\Lambda_{c}K^{+}$ interaction is attractive at\nlow energy and stronger than the $pD_{s}$ interaction though no bound state at\n$m_{\\pi}\\geq872$ MeV."
    },
    {
        "anchor": "CL2QCD - Lattice QCD based on OpenCL: We present the Lattice QCD application CL2QCD, which is based on OpenCL and\ncan be utilized to run on Graphic Processing Units as well as on common CPUs.\nWe focus on implementation details as well as performance results of selected\nfeatures. CL2QCD has been successfully applied in LQCD studies at finite\ntemperature and density and is available at\nhttp://code.compeng.uni-frankfurt.de/projects/clhmc .",
        "positive": "An Investigation of the Soft Pion Relation in Quenched Lattice QCD: A lattice determination of the form factor and decay constants for the\nsemileptonic decay of heavy pseudoscalar (PS) mesons at zero recoil is\npresented from which the soft pion relation is satisfied. Chiral extrapolation\nof the form factor is performed at constant $q^2$. Pole dominance is used to\nextrapolate the form factor in heavy quark mass. At the B mass, the form factor\nat zero recoil lies somewhat below the ratio of decay constants; the relation\nremains satisfied within error."
    },
    {
        "anchor": "Crossing the c=1 barrier in 2d Lorentzian quantum gravity: In an extension of earlier work we investigate the behaviour of\ntwo-dimensional Lorentzian quantum gravity under coupling to a conformal field\ntheory with c>1. This is done by analyzing numerically a system of eight Ising\nmodels (corresponding to c=4) coupled to dynamically triangulated Lorentzian\ngeometries. It is known that a single Ising model couples weakly to Lorentzian\nquantum gravity, in the sense that the Hausdorff dimension of the ensemble of\ntwo-geometries is two (as in pure Lorentzian quantum gravity) and the matter\nbehaviour is governed by the Onsager exponents. By increasing the amount of\nmatter to 8 Ising models, we find that the geometry of the combined system has\nundergone a phase transition. The new phase is characterized by an anomalous\nscaling of spatial length relative to proper time at large distances, and as a\nconsequence the Hausdorff dimension is now three. In spite of this qualitative\nchange in the geometric sector, and a very strong interaction between matter\nand geometry, the critical exponents of the Ising model retain their Onsager\nvalues. This provides evidence for the conjecture that the KPZ values of the\ncritical exponents in 2d Euclidean quantum gravity are entirely due to the\npresence of baby universes. Lastly, we summarize the lessons learned so far\nfrom 2d Lorentzian quantum gravity.",
        "positive": "Topology and $\u03b8$ dependence in finite temperature $G_2$ lattice\n  gauge theory: In this work we study the topological properties of the $G_2$ lattice gauge\ntheory by means of Monte Carlo simulations. We focus on the behaviour of\ntopological quantities across the deconfinement transition and investigate\nobservables related to the $\\theta$ dependence of the free energy. As in\n$SU(N)$ gauge theories, an abrupt change happens at deconfinement and an\ninstanton gas behaviour rapidly sets in for $T>T_c$."
    },
    {
        "anchor": "Width difference in the Bs system from lattice HQET: We present recent results for the prediction of the Bs lifetime difference\nfrom lattice Heavy Quark Effective Theory simulations. In order to get a\nnext-to-leading order result we have calculated the matching between QCD and\nHQET and the two loop anomalous dimension in the HQET for all the \\Delta B=2\noperators, in particular for the operators which enter in the width difference.\nWe obtain for the Bs lifetime difference, (\\Delta\\Gamma_Bs/\\Gamma_Bs)=(5.1+/-\n1.9+/- 1.7)10^(-2).",
        "positive": "Numerical determination of entanglement entropy for a sphere: We apply Srednicki's regularization to extract the logarithmic term in the\nentanglement entropy produced by tracing out a real, massless, scalar field\ninside a three dimensional sphere in 3+1 flat spacetime. We find numerically\nthat the coefficient of the logarithm is -1/90 to 0.2 percent accuracy, in\nagreement with an existing analytical result."
    },
    {
        "anchor": "Quenched chiral perturbation theory for baryon form factors: A new intuitive method for the rapid calculation of the leading nonanalytic\nbehavior of hadronic observables in quenched chiral perturbation theory is\npresented. After proving the technique in a consideration of baryon masses, the\nquenched magnetic moments of octet baryons are addressed. The technique\nprovides a separation of magnetic moment contributions into full, sea, valence\nand quenched valence contributions, the latter being the conventional view of\nthe quenched approximation. Both baryon mass and meson mass violations of\nSU(3)-flavor symmetry are accounted for. A comprehensive examination of the\nindividual quark-sector contributions to octet baryon magnetic moments reveals\nthat the u-quark contribution to the proton magnetic moment provides an optimal\nopportunity to directly view nonanalytic behavior associated with the quenched\nmeson cloud of baryons in the quenched approximation.",
        "positive": "Sigma-resonance and convergence of chiral perturbation theory: The dimensionless parameter $\\xi' = M^2/(16 \\pi^2 F^2)$, where $F$ is the\npion decay constant in the chiral limit and $M$ is the pion mass at leading\norder in the quark mass, is expected to control the convergence of chiral\nperturbation theory applicable to QCD. Here we demonstrate that a strongly\ncoupled lattice gauge theory model with the same symmetries as two-flavor QCD\nbut with a much lighter $\\sigma$-resonance is different. Our model allows us to\nstudy efficiently the convergence of chiral perturbation theory as a function\nof $\\xi'$. We first confirm that the leading low energy constants appearing in\nthe chiral Lagrangian are the same when calculated from the $\\epsilon$-regime\nand the $p$-regime. However, $\\xi' \\lesssim 0.002$ is necessary before 1-loop\nchiral perturbation theory predicts the data within 1%. However, for $\\xi' >\n0.0035$ the data begin to deviate qualitatively from 1-loop chiral perturbation\ntheory predictions. We argue that this qualitative change is due to the\npresence of a light $\\sigma$-resonance in our model. Our findings may be useful\nfor lattice QCD studies."
    },
    {
        "anchor": "The Large $N_c$ limit of QCD on the lattice: We review recent progress in the study of the large $N_c$ limit of gauge\ntheories from lattice simulations. The focus is not only the planar limit but\nalso the size of ${\\mathcal O}(N_c^{-1})$ corrections for values of $N_c\\gtrsim\n3$. Some concrete examples of the topics we include are tests of large-$N_c$\nfactorization, the topological susceptibility, the glueball, meson and baryon\nspectra, the chiral dependence of masses and decay constants, and weak matrix\nelements related to the $\\Delta I=1/2$ rule in kaon decays.",
        "positive": "Optimised Dirac Operators on the Lattice: Construction, Properties and\n  Applications: We review a number of topics related to block variable renormalisation group\ntransformations of quantum fields on the lattice, and to the emerging perfect\nlattice actions. We first illustrate this procedure by considering scalar\nfields. Then we proceed to lattice fermions, where we discuss perfect actions\nfor free fields, for the Gross-Neveu model and for a supersymmetric spin model.\nWe also consider the extension to perfect lattice perturbation theory, in\nparticular regarding the axial anomaly and the quark gluon vertex function.\nNext we deal with properties and applications of truncated perfect fermions,\nand their chiral correction by means of the overlap formula. This yields a\nformulation of lattice fermions, which combines exact chiral symmetry with an\noptimisation of further essential properties. We summarise simulation results\nfor these so-called overlap-hypercube fermions in the two-flavour Schwinger\nmodel and in quenched QCD. In the latter framework we establish a link to\nChiral Perturbation Theory, both, in the p-regime and in the epsilon-regime. In\nparticular we present an evaluation of the leading Low Energy Constants of the\nchiral Lagrangian - the chiral condensate and the pion decay constant - from\nQCD simulations with extremely light quarks."
    },
    {
        "anchor": "The operator product expansion on the lattice: We investigate the Operator Product Expansion (OPE) on the lattice by\ndirectly measuring the product <Jmu Jnu> (where J is the vector current) and\ncomparing it with the expectation values of bilinear operators. This will\ndetermine the Wilson coefficients in the OPE from lattice data, and so give an\nalternative to the conventional methods of renormalising lattice structure\nfunction calculations. It could also give us access to higher twist quantities\nsuch as the longitudinal structure function F_L = F_2 - 2 x F_1. We use overlap\nfermions because of their improved chiral properties, which reduces the number\nof possible operator mixing coefficients.",
        "positive": "Low-lying Wilson Dirac operator eigenvector mixing in dynamical overlap\n  Hybrid Monte-Carlo: Current dynamical overlap fermion hybrid Monte Carlo simulations encounter\nlarge fermionic forces when there is mixing between near zero-eigenvectors of\nthe kernel operator. This leads to low acceptance rates when there is a large\ndensity of near zero eigenvectors. I present a method where these large forces\nare eliminated and the large action jumps seen when two eigenvectors approach\nzero are significantly reduced. This significantly increases the stability of\nthe algorithm, and allows the use of larger integration time steps."
    },
    {
        "anchor": "In-medium static quark potential from spectral functions on realistic\n  HISQ ensembles: We explore the interactions between a quark anti-quark pair in a thermal\nmedium based on lattice QCD ensembles with $N_f = 2+1$ dynamical HISQ flavors.\nOur dataset spans the phenomenologically relevant temperature range between\nT=140MeV-2GeV based on lattice sizes $N_\\tau=10,12$ and $16$, with an aspect\nratio of $N_\\sigma/N_\\tau=4$. The peak position $\\Omega$ and the width $\\Gamma$\nof the spectral function of Wilson-line correlators in Coulomb gauge is\ncomputed. We assess the information content in the correlation functions and\ndeploy three complementary strategies to reconstruct spectral information:\nmodel fits, Pad\\'e approximation and the Bayesian BR method. Limitations of\neach approach are carefully assessed.",
        "positive": "Topological susceptibility and axial symmetry at finite temperature: We consider the simulation of finite temperature QCD with two flavors of\ndynamical overlap fermions in order to study the suppression of the axial U(1)\nsymmetry breaking at the chiral phase transition point. As a preliminary study,\npure gauge simulations are performed to investigate how fixing the topology\naffects physical quantities like the topological susceptibility, $\\chi_t$, at\nfinite temperature, showing that it is possible to reconstruct known results\nfrom the fixed topology sector. First results on the degeneracy of meson\ncorrelators in the high temperature QGP sector are shown."
    },
    {
        "anchor": "Baryon Interactions from Lattice QCD: We report on new attempt to investigate baryon-baryon interactions in lattice\nQCD. From the Bethe-Salpeter (BS) wave function, we have successfully extracted\nthe nucleon-nucleon ($NN$) potentials in quenched QCD simulations, which\nreproduce qualitative features of modern $NN$ potentials. The method has been\nextended to obtain the tensor potential as well as the central potential and\nalso applied to the hyperon-nucleon ($YN$) interactions, in both quenched and\nfull QCD.",
        "positive": "Non-renormalizability of the HMC algorithm: In lattice field theory, renormalizable simulation algorithms are attractive,\nbecause their scaling behaviour as a function of the lattice spacing is\npredictable. Algorithms implementing the Langevin equation, for example, are\nknown to be renormalizable if the simulated theory is. In this paper we show\nthat the situation is different in the case of the molecular-dynamics evolution\non which the HMC algorithm is based. More precisely, studying the phi^4 theory,\nwe find that the hyperbolic character of the molecular-dynamics equations leads\nto non-local (and thus non-removable) ultraviolet singularities already at\none-loop order of perturbation theory."
    },
    {
        "anchor": "Simplicial Quantum Gravity: This is my PhD thesis on four-dimensional simplicial quantum gravity using\nthe dynamical triangulation model. Most of the results we have published in\nseparate papers are collected here for your convenience. Some new results have\nbeen added as well. Besides these results this thesis also contains an\nintroduction to simplicial quantum gravity and a detailed description of my\ndynamical triangulation program for arbitrary dimension. Some small formal\nparts are in Dutch.",
        "positive": "Spectrum of the fixed point Dirac operator in the Schwinger model: Recently, properties of the fixed point action for fermion theories have been\npointed out indicating realization of chiral symmetry on the lattice. We check\nthese properties by numerical analysis of the spectrum of a parametrized fixed\npoint Dirac operator investigating also microscopic fluctuations and fermion\ncondensation."
    },
    {
        "anchor": "Two-loop matching of the chromo-magnetic dipole operator with the\n  gradient flow: The chromo-magnetic dipole operator is expressed in terms of operators at\nfinite flow time in the gradient-flow formalism. The matching coefficients are\nevaluated through next-to-next-to-leading order QCD.",
        "positive": "The lattice and quantized Yang-Mills theory: Quantized Yang-Mills fields lie at the heart of our understanding of the\nstrong nuclear force. To understand the theory at low energies, we must work in\nthe strong coupling regime. The primary technique for this is the lattice.\nWhile basically an ultraviolet regulator, the lattice avoids the use of a\nperturbative expansion. I discuss the historical circumstances that drove us to\nthis approach, which has had immense success, convincingly demonstrating quark\nconfinement and obtaining crucial properties of the strong interactions from\nfirst principles."
    },
    {
        "anchor": "Chiral symmetry and the Yang--Mills gradient flow: In the last few years, the Yang--Mills gradient flow was shown to be an\nattractive tool for non-perturbative studies of non-Abelian gauge theories.\nHere a simple extension of the flow to the quark fields in QCD is considered.\nAs in the case of the pure-gauge gradient flow, the renormalizability of\ncorrelation functions involving local fields at positive flow times can be\nestablished using a representation through a local field theory in 4+1\ndimensions. Applications of the extended flow in lattice QCD include\nnon-perturbative renormalization and O(a) improvement as well as accurate\ncalculations of the chiral condensate and of the pseudo-scalar decay constant\nin the chiral limit.",
        "positive": "Lattice QCD at finite T and \u03bcand the critical point of QCD: We propose a method to study lattice QCD at finite T and \\mu. We compare it\nwith direct results and with the Glasgow method by using n_f=4 QCD at\nIm(\\mu)\\neq 0. We locate the critical endpoint (E) of QCD on the Re(\\mu)-T\nplane. In this study we use n_f=2+1 dynamical staggered quarks with\nsemi-realistic masses on L_t=4 lattices."
    },
    {
        "anchor": "Leading Power Accuracy in Lattice Calculations of Parton Distributions: In lattice-QCD calculations of parton distribution functions (PDFs) via\nlarge-momentum effective theory, the leading power (twist-three) correction\nappears as ${\\cal O}(\\Lambda_{\\rm QCD}/P^z)$ due to the linear-divergent\nself-energy of Wilson line in quasi-PDF operators. For lattice data with hadron\nmomentum $P^z$ of a few GeV, this correction is dominant in matching, as large\nas 30\\% or more. We show how to eliminate this uncertainty through choosing the\nmass renormalization parameter consistently with the resummation scheme of the\ninfrared-renormalon series in perturbative matching coefficients. An example on\nthe lattice pion PDF data at $P^z = 1.9$ GeV shows an improvement of matching\naccuracy by a factor of more than $3\\sim 5$ in the expansion region $x= 0.2\\sim\n0.5$.",
        "positive": "D semileptonic form factors and |V_cs(d)| from 2+1 flavor lattice QCD: The measured partial widths of the semileptonic decays D to K l nu and D to\npi l nu can be combined with the form factors calculated on the lattice to\nextract the CKM matrix elements |V_cs| and |V_cd|. The lattice calculations can\nbe checked by comparing the form factor shapes from the lattice and experiment.\nWe have generated a sizable data set by using heavy clover quarks with the\nFermilab interpretation for charm and asqtad staggered light quarks on 2+1\nflavor MILC ensembles with lattice spacings of approximately 0.12, 0.09, 0.06,\nand 0.045 fm. Preliminary fits to staggered chiral perturbation theory suggest\nthat we can reduce the uncertainties in the form factors at zero invariant mass\nto below 5%."
    },
    {
        "anchor": "Universality Class of $O(N)$ Models: We point out that existing numerical data on the correlation length and\nmagnetic susceptibility suggest that the two dimensional $O(3)$ model with\nstandard action has critical exponent $\\eta=1/4$, which is inconsistent with\nasymptotic freedom. This value of $\\eta$ is also different from the one of the\nWess-Zumino-Novikov-Witten model that is supposed to correspond to the $O(3)$\nmodel at $\\theta=\\pi$.",
        "positive": "Questionable and unquestionable in the perturbation theory of\n  non-Abelian models: We show, by explicit computation, that bare lattice perturbation theory in\nthe two-dimensional O(n) nonlinear $\\sigma$ models with superinstanton boundary\nconditions is divergent in the limit of an infinite number of points\n$|\\Lambda|$. This is the analogue of David's statement that renormalized\nperturbation theory of these models is infrared divergent in the limit where\nthe physical size of the box tends to infinity. We also give arguments which\nsupport the validity of the bare perturbative expansion of short-distance\nquantities obtained by taking the limit $|\\Lambda|\\to\\infty$ term by term in\nthe theory with more conventional boundary conditions such as Dirichlet,\nperiodic, and free."
    },
    {
        "anchor": "Perturbing QCD with external fields: We present some up-to-date results on QCD phase transition in a\nchromomagnetic constant background field and in an abelian monopole background\nfield. Our results indicate that the QCD critical temperature is not modified\nby a monopole background field, whilst it is modified by a constant\nchromomagnetic field. We improve our earlier estimate of the QCD critical\nparameters in a chromomagnetic background field by performing lattice\nsimulations with weaker fields.",
        "positive": "Magnetic monopoles in the high temperature phase of Yang-Mills theories: We investigate the properties of thermal abelian magnetic monopoles in the\nhigh temperature phase of Yang--Mills theories, following a recent proposal for\ntheir identification on lattice configurations. The study is done for SU(2)\npure gauge theory, for temperatures going up to about 10 times the deconfining\ntemperature and using the Maximal Abelian gauge to perform the abelian\nprojection. We find that the monopole density has a well defined continuum\nlimit. Its temperature dependence disagrees with a free particle gas prediction\nand is instead well described by a $T^3/(\\log (T/\\Lambda))^\\alpha$ behaviour in\nall the explored range, with $\\alpha \\sim 2$ and $\\Lambda \\sim 100$ MeV. Also\nthe study of spatial correlations of thermal monopoles shows the presence of\nnon-trivial interactions among them. Finally, we discuss the gauge dependence\nof our results, showing that it is significant and that, even within the\nMaximal Abelian gauge, Gribov copy effects are important."
    },
    {
        "anchor": "Monopoles of the Dirac type and color confinement in QCD -- Study of the\n  continuum limit: Non-Abelian gauge fields having a line-singularity of the Dirac type lead us\nto violation of the non-Abelian Bianchi identity. The violation as an operator\nis equivalent to violation of Abelian-like Bianchi identities corresponding to\neight Abelian-like conserved magnetic monopole currents of the Dirac type in\n$SU(3)$ QCD. It is very interesting to study if these new Abelian-like\nmonopoles are responsible for color confinement in the continuum $SU(3)$ QCD,\nsince any reliable candidate of color magnetic monopoles is not known yet. If\nthese new Abelian-like monopoles exist in the continuum limit, the Abelian dual\nMeissner effect occurs, so that the linear part of the static potential between\na quark-antiquark pair is reproduced fully by those of Abelian and monopole\nstatic potentials. These phenomena are called here as perfect Abelian and\nmonopole dominances. It is shown that the perfect Abelian dominance is\nreproduced fairly well, whereas the perfect monopole dominance seems to be\nrealized for large $\\beta$ when use is made of the smooth lattice\nconfigurations in the maximally Abelian (MA) gauge. Making use of a block spin\ntransformation with respect to monopoles, the scaling behaviors of the monopole\ndensity and the effective monopole action are studied. Both monopole density\nand the effective monopole action which are usually a two-point function of\n$\\beta$ and the number of times $n$ of the block spin transformation are a\nfunction of $b=na(\\beta)$ alone for $n=1,2,3,4,6,8,12$. If the scaling behavior\nis seen for up to larger $n$, it shows the existence of the continuum limit,\nsince $a(\\beta)\\to 0$ when $n\\to\\infty$ for fixed $b=na(\\beta)$. Along with the\nprevious results without any gauge fixing, these new results obtained in MA\ngauge suggest that the new Abelian-like monopoles play the role of color\nconfinement in $SU(3)$ QCD.",
        "positive": "Baryon Mass Extrapolation: Consideration of the analytical properties of pion-induced baryon\nself-energies leads to new functional forms for the extrapolation of light\nbaryon masses. These functional forms reproduce the leading non-analytic\nbehavior of chiral perturbation theory, the correct heavy-quark limit and have\nthe advantage of containing information on the extended structure of hadrons.\nThe forms involve only three unknown parameters which may be optimized by\nfitting to present lattice data. Recent dynamical fermion results from CP-PACS\nand UK-QCD are extrapolated using these new functional forms. We also use these\nfunctions to probe the limit of the chiral perturbative regime and shed light\non the applicability of chiral perturbation theory to the extrapolation of\npresent lattice QCD results."
    },
    {
        "anchor": "Scaling and topology in the 2-d O(3) $\u03c3$-model on the lattice with\n  the fixed point action: We study scaling properties and topological aspects of the 2--d O(3)\nnon--linear $\\sigma$--model on the lattice with the parametrized fixed point\naction recently proposed by P.~Hasenfratz and F.~Niedermayer. The behavior of\nthe mass gap confirms the good properties of scaling of the fixed point action.\nConcerning the topology, lattice classical solutions are proved to be very\nstable under local minimization of the action; this outcome ensures the\nreliability of the cooling method for the computation of the topological\nsusceptibility, which indeed reproduces the results of the field theoretical\napproach. Disagreement is instead observed with a different approach in which\nthe fixed point topological charge operator is used: we argue that the\ndiscrepancy is related to the ultraviolet dominated nature of the model.",
        "positive": "The $KD$, $\u03b7D_s$ interaction in finite volume and the nature of the\n  $D_{s^* 0}(2317)$ resonance: An SU(4) extrapolation of the chiral unitary theory in coupled channels done\nto study the scalar mesons in the charm sector is extended to produce results\nin finite volume. The theory in the infinite volume produces dynamically the\n$D_{s^*0}(2317)$ resonance by means of the coupled channels $KD$, $\\eta D_s$.\nEnergy levels in the finite box are evaluated and, assuming that they would\ncorrespond to lattice results, the inverse problem of determining the bound\nstates and phase shifts in the infinite volume from the lattice data is\naddressed. We observe that it is possible to obtain accurate $KD$ phase shifts\nand the position of the $D_{s^*0}(2317)$ state, but it requires the explicit\nconsideration of the two coupled channels in the analysis if one goes close to\nthe $\\eta D_s$ threshold. We also show that the finite volume spectra look\nrather different in case the $D_{s^*0}(2317)$ is a composite state of the two\nmesons, or if it corresponds to a non molecular state with a small overlap with\nthe two meson system. We then show that a careful analysis of the finite volume\ndata can shed some light on the nature of the $D_{s^*0}(2317)$ resonance as a\n$KD$ molecule or otherwise."
    },
    {
        "anchor": "Twisted-mass QCD, O(a) improvement and Wilson chiral perturbation theory: We point out a caveat in the proof for automatic O(a) improvement in twisted\nmass lattice QCD at maximal twist angle. With the definition for the twist\nangle previously given by Frezzotti and Rossi, automatic O(a) improvement can\nfail unless the quark mass satisfies m_q >> a^2 Lambda_QCD^3. We propose a\ndifferent definition for the twist angle which does not require a restriction\non the quark mass for automatic O(a) improvement. In order to illustrate\nexplicitly automatic O(a) improvement we compute the pion mass in the\ncorresponding chiral effective theory. We consider different definitions for\nmaximal twist and show explicitly the absence or presence of the leading O(a)\neffect, depending on the size of the quark mass.",
        "positive": "Lattice simulations for the running coupling constant of QCD: The strong coupling constant alpha_s(mu_0), taken at a fixed reference scale\nmu_0, is the single free parameter of QCD and should be known to the highest\navailable precision. The value of alpha_s should also be determined with good\naccuracy over as large a range of scales as possible, in order to reveal\npotential anomalous running in the strength of the strong interaction. Lattice\nQCD is now able to calculate alpha_s with accuracy comparable to or better than\nexperiment. We review the status of such lattice calculations in quenched and\nfull QCD."
    },
    {
        "anchor": "Quark-gluon plasma in an external magnetic field: Using numerical simulations of lattice QCD we calculate the effect of an\nexternal magnetic field on the equation of state of the quark-gluon plasma. The\nresults are obtained using a Taylor expansion of the pressure with respect to\nthe magnetic field for the first time. The coefficients of the expansion are\ncomputed to second order in the magnetic field. Our setup for the external\nmagnetic field avoids complications arising from toroidal boundary conditions,\nmaking a Taylor series expansion straightforward. This study is exploratory and\nis meant to serve as a proof of principle.",
        "positive": "Looking at the gluon moment of the nucleon with dynamical twisted mass\n  fermions: To understand the structure of hadrons it is important to know the PDF of\ntheir constituents, the quarks and gluons. In our work we aim to compute the\nfirst moment of the gluon PDF $\\langle x \\rangle_g$ for the nucleon. We follow\ntwo possible approaches in order to extract the gluon moment: the\nFeynman-Hellmann theorem and a direct method with smearing of the gluon\noperator. We present preliminary results computed on $24^3 \\times 48$ lattices\nfor the case where the Feynman-Hellman theorem is used and $32^3 \\times 64$\nlattices for the direct method, employing $N_f=2+1+1$ maximally twisted mass\nfermions."
    },
    {
        "anchor": "Are there Local Minima in the Magnetic Monopole Potential in Compact\n  QED?: We investigate the influence of the granularity of the lattice on the\npotential between monopoles. Using the flux definition of monopoles we\nintroduce their centers of mass and are able to realize continuous shifts of\nthe monopole positions. We find periodic deviations from the $1/r$-behavior of\nthe monopole-antimonopole potential leading to local extrema. We suppose that\nthese meta-stabilities may influence the order of the phase transition in\ncompact QED.",
        "positive": "Phase diagram, symmetry breaking, and critical behavior of\n  three-dimensional lattice multiflavor scalar chromodynamics: We study the nature of the phase diagram of three-dimensional lattice models\nin the presence of nonabelian gauge symmetries. In particular, we consider a\nparadigmatic model for the Higgs mechanism, lattice scalar chromodynamics with\nN_f flavors, characterized by a nonabelian SU(N_c) gauge symmetry. For N_f>1\n(multiflavor case), it presents two phases separated by a transition line where\na gauge-invariant order parameter condenses, being associated with the breaking\nof the residual global symmetry after gauging. The nature of the phase\ntransition line is discussed within two field-theoretical approaches, the\ncontinuum scalar chromodynamics and the Landau-Ginzburg- Wilson (LGW) Phi4\napproach based on a gauge-invariant order parameter. Their predictions are\ncompared with simulation results for N_f=2, 3 and N_c = 2, 3, and 4. The LGW\napproach turns out to provide the correct picture of the critical behavior,\nunlike continuum scalar chromodynamics."
    },
    {
        "anchor": "Hadron spectrum of QCD with one quark flavor: The hadron spectrum of one flavor QCD is studied by Monte Carlo simulations.\nThe Symanzik tree-level-improved Wilson action is used for the gauge field and\nthe Wilson action for the fermion. The theory is simulated by a polynomial\nhybrid Monte Carlo algorithm (PHMC). The mass spectrum of hadronic bound states\nis investigated at two different lattice spacings: a ~ 0.37r_0 and a ~ 0.27r_0,\ncorresponding to ~0.19fm and ~0.13fm in ordinary QCD. The lattice extension is\nfixed to L ~ 4.4r_0 (~2.2fm). The lightest simulated quark mass corresponds to\na pion with mass ~270MeV. Properties of the theory are analyzed by making use\nof the ideas of partially quenched chiral perturbation theory (PQChPT). The\nsymmetry of the single flavor theory can be artificially enhanced by adding\nextra valence quarks, which can be interpreted as u and d quarks. Operators in\nthe valence pion sector can be built. Masses and decay constants are analyzed\nby using PQChPT formulae at next-to-leading order.",
        "positive": "Compact Gauge Fields on Causal Dynamical Triangulations: a 2D case study: We discuss the discretization of Yang-Mills theories on Dynamical\nTriangulations in the compact formulation, with gauge fields living on the\nlinks of the dual graph associated with the triangulation, and the numerical\ninvestigation of the minimally coupled system by Monte Carlo simulations. We\nprovide, in particular, an explicit construction and implementation of the\nMarkov chain moves for 2D Causal Dynamical Triangulations coupled to either\n$U(1)$ or $SU(2)$ gauge fields; the results of exploratory numerical\nsimulations on a toroidal geometry are also presented for both cases. We study\nthe critical behavior of gravity related observables, determining the\nassociated critical indices, which turn out to be independent of the bare gauge\ncoupling: we obtain in particular $\\nu = 0.496(7)$ for the critical index\nregulating the divergence of the correlation length of the volume profiles.\nGauge observables are also investigated, including holonomies (torelons) and,\nfor the $U(1)$ gauge theory, the winding number and the topological\nsusceptibility. An interesting result is that the critical slowing down of the\ntopological charge, which affects various lattice field theories in the\ncontinuum limit, seems to be strongly suppressed (i.e., by orders of magnitude)\nby the presence of a locally variable geometry: that may suggest possible ways\nfor improvement also in other contexts."
    },
    {
        "anchor": "QCD in a finite box: Numerical test studies in the three\n  Leutwyler-Smilga regimes: The Leutwyler-Smilga prediction regarding the (ir)relevance of the global\ntopological charge for QCD in a finite box is subject to a test. To this end\nthe lattice version of a suitably chosen analogue (massive 2-flavour Schwinger\nmodel) is analyzed in the small ($V\\Sigma m \\ll 1$), intermediate ($V\\Sigma m\n\\simeq 1$) and large ($V\\Sigma m \\gg 1$) Leutwyler-Smilga regimes. The\npredictions for the small and large regimes are confirmed and illustrated. New\nresults about the role of the functional determinant in all three regimes and\nabout the sensitivity of physical observables on the topological charge in the\nintermediate regime are presented.",
        "positive": "The nucleon electromagnetic form factors from Lattice QCD: We evaluate the isovector nucleon electromagnetic form factors in quenched\nand full QCD on the lattice using Wilson fermions. In the quenched theory we\nuse a lattice of spatial size 3 fm at beta=6.0 enabling us to reach low\nmomentum transfers and a lowest pion mass of about 400 MeV. In the full theory\nwe use a lattice of spatial size 1.9 fm at beta=5.6 and lowest pion mass of\nabout 380 MeV enabling comparison with the results obtained in the quenched\ntheory. We compare our lattice results to the isovector part of the\nexperimentally measured form factors."
    },
    {
        "anchor": "Probing the Continuum Limit in Non-Compact QED: New Results on Large\n  Lattices: We present new Monte Carlo results in non-compact lattice QED with staggered\nfermions down to m_0 = 0.005. This extends our previous investigations on the\nnature of the continuum limit of QED.",
        "positive": "The Upsilon spectrum and the determination of the lattice spacing from\n  lattice QCD including charm quarks in the sea: We give results for the Upsilon spectrum from lattice QCD using an improved\nversion of the NRQCD action for b quarks which includes radiative corrections\nto kinetic terms at O(v^4) in the velocity expansion. We also include for the\nfirst time the effect of up, down, strange and charm quarks in the sea using\n'second generation' gluon field configurations from the MILC collaboration.\nUsing the {\\Upsilon} 2S - 1S splitting to determine the lattice spacing, we are\nable to obtain the 1P - 1S splitting to 1.4% and the 3S - 1S splitting to 2.4%.\nOur improved result for M (Upsilon) - M (eta_b) is 70(9) MeV and we predict\nM(Upsilon) - M(eta_b') = 35(3) MeV. We also calculate pi, K and eta_s\ncorrelators using the Highly Improved Staggered Quark action and perform a\nchiral and continuum extrapolation to give values for M(eta_s) (0.6893(12) GeV)\nand f_{eta_s} (0.1819(5) GeV) that allow us to tune the strange quark mass as\nwell as providing an independent and consistent determination of the lattice\nspacing. Combining the NRQCD and HISQ analyses gives mb/ms = 54.7(2.5) and a\nvalue for the heavy quark potential parameter of r_1 = 0.3209(26) fm."
    },
    {
        "anchor": "Towards the QCD equation of state at the physical point using Wilson\n  fermion: We study the (2+1)-flavor QCD at nonzero temperatures using nonperturbatively\nimproved Wilson quarks of the physical masses by the fixed scale approach. We\nperform physical point simulations at finite temperatures with the coupling\nparameters which were adopted by the PACS-CS Collaboration in their studies\nusing the reweighting technique. Zero temperature values are obtained on the\nPACS-CS configurations which are open to the public on the ILDG/JLDG. Finite\ntemperature configurations are generated with the RHMC algorithm. The lattice\nsizes are $32^3 \\times N_t$ with $N_t=14$, 13, $\\cdots$, 4 which correspond to\n$T \\approx 160$--550 MeV. We present results of some basic observables at these\ntemperatures and the status of our calculation of the equation of state.",
        "positive": "The sphaleron energy for SU(2)-Higgs from cooling: The cooling algorithm for saddle points presented in ref. [1] is generalized\nto obtain static classical solutions of the SU(2)-Higgs field theory in the\nlimit of infinite Higgs self-coupling. The sphaleron energy obtained via this\nalgorithm is ${\\cal E}_{\\rm sph}= 5.08(7)\\,M_W/\\alpha_W$ to be compared with\n5.0707 obtained in the variational approach [2]."
    },
    {
        "anchor": "Confinement From The Gauge Invariant Abelian Decomposition: A common approach while considering confinement is to study the dominance of\nan Abelian subgroup of the SU(3) gauge Links. A good way to find the Abelian\ncomponent of the field is through the Cho-Guan-De gauge invariant Abelian\nDecomposition, which uses a carefully chosen direction vector $n$ to split the\ngauge field into an Abelian restricted field and a remnant coloured field. The\nrestricted field can be further subdivided into topological and non-topological\nterms. We show that there is a choice of $n$ which allows us to exactly\nrepresent the Wilson Loop of full QCD as a function of only the restricted\nAbelian field without requiring any path ordering or additional path integrals.\nWe present numerical evidence showing that the topological part of the\nrestricted field dominates the string tension. We also show that $n$ contains\ncertain topological objects, which, if they exist, will be at least partially\nresponsible for confinement. These leave distinctive patterns in the restricted\nfield strength, and we search for these structures in quenched lattice QCD.",
        "positive": "Deformations of infrared-conformal theories in two dimensions: We study two exactly solvable two-dimensional conformal models, the critical\nIsing model and the Sommerfield model, on the lattice. We show that finite-size\neffects are important and depend on the aspect ratio of the lattice. In\nparticular, we demonstrate how to obtain the correct massless behavior from an\ninfinite tower of finite-size-induced masses and show that it is necessary to\nfirst take the cylindrical geometry limit in order to get correct results. In\nthe Sommerfield model we also introduce a mass deformation to measure the mass\nanomalous dimension, $\\gamma_m$. We find that the explicit scale breaking of\nthe lattice setup induces corrections which must be taken into account in order\nto reproduce $\\gamma_m$ at the infrared fixed point. These results can be used\nto improve the methodology in the search for the conformal window in QCD-like\ntheories with many flavors."
    },
    {
        "anchor": "Two-Particle Elastic Scattering in a Finite Volume Including QED: The presence of long-range interactions violates a condition necessary to\nrelate the energy of two particles in a finite volume to their S-matrix\nelements in the manner of Luscher. While in infinite volume, QED contributions\nto low-energy charged particle scattering must be resummed to all orders in\nperturbation theory (the Coulomb ladder diagrams), in a finite volume the\nmomentum operator is gapped, allowing for a perturbative treatment. The leading\nQED corrections to the two-particle finite-volume energy quantization condition\nbelow the inelastic threshold, as well as approximate formulas for energy\neigenvalues, are obtained. In particular, we focus on two spinless hadrons in\nthe A1+ irreducible representation of the cubic group, and truncate the strong\ninteractions to the s-wave. These results are necessary for the analysis of\nLattice QCD+QED calculations of charged-hadron interactions, and can be\nstraightforwardly generalized to other representations of the cubic group, to\nhadrons with spin, and to include higher partial waves.",
        "positive": "Topological susceptibility with a single light quark flavour: One of the historical suggestions to tackle the strong CP problem is to take\nthe up quark mass to zero while keeping $m_d$ finite. The $\\theta$ angle is\nthen supposed to become irrelevant, i.e. the topological susceptibility\nvanishes. However, the definition of the quark mass is scheme-dependent and\nidentifying the $m_u=0$ point is not trivial, in particular with Wilson-like\nfermions. More specifically, up to our knowledge there is no theoretical\nargument guaranteeing that the topological susceptibility exactly vanishes when\nthe PCAC mass does.\n  We will present our recent progresses on the empirical check of this property\nusing $N_f=1+2$ flavours of clover fermions, where the lightest fermion is\ntuned very close to $m^{PCAC}_u$=0 and the mass of the other two is kept of the\norder of magnitude of the physical $m_s$. This choice is indeed expected to\namplify any unknown non-perturbative effect caused by $m_u\\not=m_d$. The\nsimulation is repeated for several $\\beta$s and those results, although\npreliminary, give a hint about what happens in the continuum limit."
    },
    {
        "anchor": "$\\ell N$ inclusive scattering cross sections on the lattice: Utilizing the approach recently proposed for the $\\ell N$ inclusive\nscattering cross section on the lattice, we compute the differential scattering\ncross section for the charged current process $\\ell p \\rightarrow \\nu n $ for\nvarious kinematical channels. The simulation is carried out on the 2+1 flavor\n$16^3 \\times 32 $ ensemble with Iwasaki and Domain Wall Fermion action. The\nlattice results are compared with MINER$\\nu$A result for the equivalent\nprocess.",
        "positive": "Nucleon Axial Form Factor from Domain Wall on HISQ: The Deep Underground Neutrino Experiment (DUNE) is an upcoming neutrino\noscillation experiment that is poised to answer key questions about the nature\nof neutrinos. Lattice QCD has the ability to make significant impact upon DUNE,\nbeginning with computations of nucleon-neutrino interactions with weak\ncurrents. Nucleon amplitudes involving the axial form factor are part of the\nprimary signal measurement process for DUNE, and precise calculations from LQCD\ncan significantly reduce the uncertainty for inputs into Monte Carlo\ngenerators. Recent calculations of the nucleon axial charge have demonstrated\nthat sub-percent precision is possible on this vital quantity. In these\nproceedings, we discuss preliminary results for the CalLat collaboration's\ncalculation of the axial form factor of the nucleon. These computations are\nperformed with M\\\"obius domain wall valence quarks on HISQ sea quark ensembles\ngenerated by the MILC and CalLat collaborations. The results use a variety of\nensembles including several at physical pion mass."
    },
    {
        "anchor": "Calculation of the nucleon axial charge in lattice QCD: Protons and neutrons have a rich structure in terms of their constituents,\nthe quarks and gluons. Understanding this structure requires solving Quantum\nChromodynamics (QCD). However QCD is extremely complicated, so we must\nnumerically solve the equations of QCD using a method known as lattice QCD.\nHere we describe a typical lattice QCD calculation by examining our recent\ncomputation of the nucleon axial charge.",
        "positive": "A Cluster Algorithm for the $Z_2$ Kalb-Ramond Model: A cluster algorithm is presented for the $Z_2$ Kalb-Ramond plaquette model in\nfour dimensions which dramatically reduces critical slowing. The critical\nexponent $z$ is reduced from $ z>2$ (standard Metropolis algorithm) to $z=\n0.32\\pm0.06$. The Cluster algorithm updates the monopole configuration known to\nbe responsible for the second order phase transition."
    },
    {
        "anchor": "Calculation of the heavy-hadron axial couplings g_1, g_2, and g_3 using\n  lattice QCD: In a recent letter [Phys. Rev. Lett. 108, 172003 (2012), arXiv:1109.2480] we\nhave reported on a lattice QCD calculation of the heavy-hadron axial couplings\n$g_1$, $g_2$, and $g_3$. These quantities are low-energy constants of\nheavy-hadron chiral perturbation theory (HH$\\chi$PT) and are related to the\n$B^*B\\pi$, $\\Sigma_b^*\\Sigma_b\\pi$, and $\\Sigma_b^{(*)}\\Lambda_b\\pi$ couplings.\nIn the following, we discuss important details of the calculation and give\nfurther results. To determine the axial couplings, we explicitly match the\nmatrix elements of the axial current in QCD with the corresponding matrix\nelements in HH$\\chi$PT. We construct the ratios of correlation functions used\nto calculate the matrix elements in lattice QCD, and study the contributions\nfrom excited states. We present the complete numerical results and discuss the\ndata analysis in depth. In particular, we demonstrate the convergence of\n$SU(4|2)$ HH$\\chi$PT for the axial-current matrix elements at pion masses up to\nabout 400 MeV and show the impact of the nonanalytic loop contributions.\nFinally, we present additional predictions for strong and radiative decay\nwidths of charm and bottom baryons.",
        "positive": "Random Matrix Models for Dirac Operators at finite Lattice Spacing: We study discretization effects of the Wilson and staggered Dirac operator\nwith $N_{\\rm c}>2$ using chiral random matrix theory (chRMT). We obtain\nanalytical results for the joint probability density of Wilson-chRMT in terms\nof a determinantal expression over complex pairs of eigenvalues, and real\neigenvalues corresponding to eigenvectors of positive or negative chirality as\nwell as for the eigenvalue densities. The explicit dependence on the lattice\nspacing can be readily read off from our results which are compared to\nnumerical simulations of Wilson-chRMT. For the staggered Dirac operator we have\nstudied random matrices modeling the transition from non-degenerate eigenvalues\nat non-zero lattice spacing to degenerate ones in the continuum limit."
    },
    {
        "anchor": "On the efficient numerical solution of lattice systems with low-order\n  couplings: We apply the Quasi Monte Carlo (QMC) and recursive numerical integration\nmethods to evaluate the Euclidean, discretized time path-integral for the\nquantum mechanical anharmonic oscillator and a topological quantum mechanical\nrotor model. For the anharmonic oscillator both methods outperform standard\nMarkov Chain Monte Carlo methods and show a significantly improved error\nscaling. For the quantum mechanical rotor we could, however, not find a\nsuccessful way employing QMC. On the other hand, the recursive numerical\nintegration method works extremely well for this model and shows an at least\nexponentially fast error scaling.",
        "positive": "Noncompact Gauge-Invariant Lattice Simulations: We have applied a new gauge-invariant, noncompact, Monte Carlo method to\nsimulate $U(1)$, $SU(2)$, and $SU(3)$ gauge theories on $8^4$ and $12^4$\nlattices. The Creutz ratios of the Wilson loops agree with the exact results\nfor $U(1)$ for $\\beta \\ge 1$ apart from a renormalization of the charge. The\n$SU(2)$ and $SU(3)$ Creutz ratios robustly display quark confinement at $\\beta\n= 0.5$ and $\\beta = 1.5$, respectively. At much weaker coupling, the $SU(2)$\nand $SU(3)$ Creutz ratios agree with perturbation theory after a\nrenormalization of the coupling constant."
    },
    {
        "anchor": "Transverse momentum broadening from the lattice: We present a calculation of the transverse momentum broadening of a\nhigh-energy fundamental-representation particle, as calculated\nnonperturbatively within EQCD using the technique proposed by Caron-Huot and\npioneered by Panero, Sch\\\"afer, and Rummukainen. Our results are continuum\nextrapolated and provided at four temperatures: 250 MeV, 500 MeV, 1 GeV, and\n100 GeV.",
        "positive": "Critical properties and monopoles in U(1) lattice gauge theory: We present a detailed study of the properties of the phase transition in the\nfour-dimensional compact U(1) lattice gauge theory supplemented by a monopole\nterm, for values of the monopole coupling $\\lambda$ such that the transition is\nof second order. By a finite size analysis we show that at $\\lambda= 0.9$ the\ncritical exponent is already characteristic of a second-order transition.\nMoreover, we find that this exponent is definitely different from the one of\nthe Gaussian case. We further observe that the monopole density becomes\napproximately constant in the second-order region. Finally we reveal the\nunexpected phenomenon that the phase transition persists up to very large\nvalues of $\\lambda$, where the transition moves to (large) negative $\\beta$."
    },
    {
        "anchor": "Nucleon isovector momentum fraction, helicity and transversity moment\n  using Lattice QCD: We present our recent high precision calculations (Phys. Rev. D102 (2020)\nno.5, 054512 and JHEP 04 (2021) 044, JHEP 21 (2020) 004) of the first moment of\nnucleon isovector polarized, unpolarized and transversity distributions, i.e.,\nmomentum fraction, helicity and transversity moment, respectively. We use the\nstandard method for the calculation of these moments (via matrix elements of\ntwist two operators), and carry out a detailed analysis of the sources of\nsystematic uncertainty, in particular of excited state contributions. Our\ncalculations have been performed using two different lattice setups\n(Clover-on-HISQ and Clover-on-Clover), each with several ensembles. They give\nconsistent results that are in agreement with global fit analyses.",
        "positive": "Scaling and the Fractal Geometry of Two-Dimensional Quantum Gravity: We examine the scaling of geodesic correlation functions in two-dimensional\ngravity and in spin systems coupled to gravity. The numerical data support the\nscaling hypothesis and indicate that the quantum geometry develops a\nnon-perturbative length scale. The existence of this length scale allows us to\nextract a Hausdorff dimension. In the case of pure gravity we find d_H approx.\n3.8, in support of recent theoretical calculations that d_H = 4. We also\ndiscuss the back-reaction of matter on the geometry."
    },
    {
        "anchor": "Connected and leading disconnected hadronic light-by-light contribution\n  to the muon anomalous magnetic moment with physical pion mass: We report a lattice QCD calculation of the hadronic light-by-light\ncontribution to the muon anomalous magnetic moment at physical pion mass. The\ncalculation includes the connected diagrams and the leading,\nquark-line-disconnected diagrams. We incorporate algorithmic improvements\ndeveloped in our previous work. The calculation was performed on the $48^3\n\\times 96$ ensemble generated with a physical-pion-mass and a 5.5 fm spatial\nextent by the RBC and UKQCD collaborations using the chiral, domain wall\nfermion (DWF) formulation. We find $a_\\mu^{\\text{HLbL}} = 5.35 (1.35) \\times\n10^{- 10}$, where the error is statistical only. The finite-volume and finite\nlattice-spacing errors could be quite large and are the subject of on-going\nresearch. The omitted disconnected graphs, while expected to give a correction\nof order 10\\%, also need to be computed.",
        "positive": "Matrix product states for Hamiltonian lattice gauge theories: Over the last decade tensor network states (TNS) have emerged as a powerful\ntool for the study of quantum many body systems. The matrix product states\n(MPS) are one particular case of TNS and are used for the simulation of 1+1\ndimensional systems. In [1] we considered the MPS formalism for the simulation\nof the Hamiltonian lattice gauge formulation of 1+1 dimensional one flavor\nquantum electrodynamics, also known as the massive Schwinger model. We deduced\nthe ground state and lowest lying excitations. Furthermore, we performed a full\nquantum real-time simulation for a quench with a uniform background electric\nfield. In this proceeding we continue our work on the Schwinger model. We\ndemonstrate the advantage of working with gauge invariant MPS by comparing with\nMPS simulations on the full Hilbert space, that includes numerous non-physical\ngauge variant states. Furthermore, we compute the chiral condensate and recover\nthe predicted UV-divergent behavior."
    },
    {
        "anchor": "Searching for the QCD critical point along the\n  pseudo-critical/freeze-out line using Pad\u00e9-resummed Taylor expansions of\n  cumulants of conserved charge fluctuations: Using high-statistics datasets generated in (2+1)-flavor QCD calculations at\nfinite temperature we construct estimators for the radius of convergence from\nan eighth order series expansion of the pressure as well as the number density.\nWe show that the estimator for pressure and number density will be identical in\nthe asymptotic limit. In the vicinity of the pseudo-critical temperature,\n$T_{pc}\\simeq 156.5$~MeV, we find the estimator of the radius of convergence to\nbe $\\mu_B/T \\gtrsim\\ 3$ for strangeness-neutral matter. We also present results\nfor the pole structure of the Pad\\'e approximants for the pressure at non-zero\nvalues of the baryon chemical potential and show that the pole structure of the\n[4,4] Pad\\'e is consistent with not having a critical point at temperatures\nlarger than $135~$MeV and a baryon chemical potential smaller than $\\mu_B/T\n\\sim \\ 2.5$.",
        "positive": "Large Wilson loops with overlap and clover fermions: Two-loop evaluation\n  of the b-quark mass shift and the quark-antiquark potential: We compute, to two loops in pertubation theory, the fermionic contribution to\nrectangular RxT Wilson loops, for different values of R and T.\n  We use the overlap fermionic action. We also employ the clover action, for\ncomparison with existing results in the literature.\n  In the limit R, T -> Infinity our results lead to the shift in the b-quark\nmass. We also evaluate the perturbative static potential as T -> Infinity."
    },
    {
        "anchor": "Phase structure of QCD for general number of flavors: We investigate and elucidate the phase structure of QCD for general number of\nflavors $N_F$ with Wilson quarks, varying $N_F$ from 2 up to 300. Based on\nnumerical results combined with the result of the perturbation theory we\npropose the following picture: When $N_F \\ge 17$, there is only a trivial fixed\npoint and therefore the theory in the continuum limit is trivial. On the other\nhand, when $16 \\ge N_F \\ge 7$, there is a non-trivial fixed point and therefore\nthe theory is non-trivial with anomalous dimensions, however, without quark\nconfinement. Theories which satisfy both quark confinement and spontaneous\nchiral symmetry breaking in the continuum limit exist only for $N_F \\le 6$. We\nalso discuss the structure of the deconfining phase at finite temperatures for\nthe small number of flavors such as $N_F=2$ and 3, through a systematic study\nof it for general number of flavors.",
        "positive": "Strange Quark Physics on the Lattice: We present results for hadrons containing a strange quark in quenched lattice\nQCD. We calculate masses and decay constants using 60 gauge configurations with\nan O(a)-improved fermion action at beta = 6.2. Using the rho mass to set the\nscale, we find hadron masses within two to three standard deviations of\nexperiment. Direct comparison with experiment for decay constants is obscured\nby uncertainty in current renormalisations. Finally, we present preliminary\nresults on the semi-leptonic decay D->K. We find f_K^+(0)/Z_V = 0.75+5-4 and\nf_K^0(0)/Z_V = 0.74+4-4."
    },
    {
        "anchor": "Overlap-Dirac fermions with a small hopping parameter: We consider overlap-Dirac fermions at non-zero bare coupling and for a small\nhopping parameter, or, equivalently, large $|M|$ with $M$ the domain-wall\nheight. We prove the existence of a phase at large positive $M$ where the\nabelian axial group $U_A(1)$ is a symmetry, and the corresponding pseudo-scalar\nis an exact Goldstone boson. We also provide a conjecture for the phase diagram\nof asymptotically free gauge theories with overlap-Dirac fermions. In\nparticular, we suggest that, for large gauge coupling, the massive-fermion\nphase at negative $M$ possibly extends to all $M<4$.",
        "positive": "The Chiral Critical Point in 3-Flavour QCD: We determine the second order endpoint of the line of first order phase\ntransitions, which occur in the light quark mass regime of 3-flavour QCD at\nfinite temperature, and analyze universal properties of this chiral critical\npoint. A detailed analysis of Binder cumulants and the joint probability\ndistributions of energy like and ordering-field like observables confirms that\nthe chiral critical point belongs to the universality class of the three\ndimensional Ising model. From a calculation with improved gauge and staggered\nfermion actions we estimate that the transition is first order for\npseudo-scalar meson masses less than about 200 MeV."
    },
    {
        "anchor": "Non-perturbative renormalization of the QCD flavour-singlet local vector\n  current: We compute non-perturbatively the renormalization constant of the\nflavour-singlet local vector current $Z_V$ in lattice QCD with 3 massless\nflavours. Gluons are discretized by the Wilson plaquette action while quarks by\nthe O($a$)-improved Wilson--Dirac operator. The constant $Z_V$ is fixed by\ncomparing the expectation values (1-point functions) of the conserved and local\nvector currents at finite temperature in the presence of shifted boundary\nconditions and at non-zero imaginary chemical potential. Monte Carlo\nsimulations with a moderate computational cost allow us to obtain $Z_V$ with an\naccuracy of about 8\\textperthousand\\, for values of the inverse bare coupling\nconstant $\\beta=6/g_0^2$ in the range $5.3 \\leq \\beta \\leq 11.5$.",
        "positive": "On the phase structure of a chiral invariant Higgs-Yukawa model: In the past the construction of Higgs-Yukawa models on the lattice was\nblocked by the lack of a consistent definition of a chiral invariant Yukawa\ncoupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on\nthe overlap operator, realized by the Neuberger-Dirac operator. As a first step\ntowards a numerical examination of this model we study its phase diagram by\nmeans of an analytic 1/N-expansion, which is possible for small and for large\nvalues of the Yukawa coupling constant. In the case of strong Yukawa couplings\nthe model effectively becomes an O(4)-symmetric non-linear sigma-model."
    },
    {
        "anchor": "Application of the projective truncation and randomized singular value\n  decomposition to a higher dimension: We study the tensor renormalization group (TRG) in the dimension larger than\ntwo as the Higher-order TRG (HOTRG) with the randomized SVD method. The\nrandomized SVD and the detailed discussion on the low order tensor\nrepresentation, we can calculate the HOTRG with the reduced computational cost.\nWe also represent our method by using the cost function, and the details of the\ncost function for the isometry determine the precision, stability, and\ncalculation time. In our study, we show calculation order improvement using\nrandomized SVD. We also propose that the internal line respect for any TRG\nmethod improves the calculation without changing the order of the computational\ncost.",
        "positive": "Chiral Fermions, Anomalies and Chern-Simons Currents on the Lattice: I discuss the zeromode spectrum of lattice chiral fermions in the domain wall\nmodel suggested recently. In particular I give the critical momenta where the\nfermions cease to be chiral and show that the spectrum is directly related to\nthe behaviour of the Chern-Simons current on the lattice. First results for the\ndomain wall model on the finite lattice indicate that the relevant features of\nthe model in the infinite system survive for the finite lattice."
    },
    {
        "anchor": "Localized eigenmodes of covariant Laplacians in the Yang-Mills vacuum: As a probe of the Yang-Mills vacuum, we study numerically the eigenmode\nspectrum of the covariant lattice Laplacian operator. We find that the\neigenmodes at the low and high ends of the spectrum are localized in finite\nregions whose volume is insensitive to the lattice volume. We also find that\nthe vacuum is seen very differently by localized modes of the covariant\nLaplacian in different representations of the gauge group. In the fundamental\nrepresentation, the data suggests that the localization volume is finite in\nphysical units set by the string tension, and localization disappears when\ncenter vortices are removed. In the adjoint and j=3/2 representations the low\nand high-lying modes are far more localized, and the localization volume\nappears to scale to zero, in physical units, in the continuum limit. The\nadjoint Laplacian is insensitive to vortex removal, but we find that\nexponential localization is absent for adjoint eigenmodes in the Higgs phase of\na gauge-Higgs theory. Localization is also absent in the spectrum of the\nCoulomb gauge Faddeev-Popov operator, as required in Coulomb gauge confinement\nscenarios.",
        "positive": "Negative Coupling $\u03c6^4$ on the Lattice: Triviality of $\\phi^4$ theory in four dimensions can be avoided if the bare\ncoupling constant is negative in the UV. Theories with negative coupling can be\nput on the lattice if the integration domain for $\\phi(x)$ is contour-deformed\nfrom the real to the complex domain. In 0+1d (quantum mechanics), one can\nrecover results from $\\mathcal{PT}$-symmetric quantum mechanics in this way. In\nthis work, I report on an attempt to put negative coupling $\\phi^4$ theory in 4\ndimensions on the lattice."
    },
    {
        "anchor": "Fractional electric charge and quark confinement: Owing to their fractional electric charges, quarks are blind to\ntransformations that combine a color center phase with an appropriate\nelectromagnetic one. Such transformations are part of a global $Z_6$-like\ncenter symmetry of the Standard Model that is lost when quantum chromodynamics\n(QCD) is treated as an isolated theory. This symmetry and the corresponding\ntopological defects may be relevant to non-perturbative phenomena such as quark\nconfinement, much like center symmetry and ordinary center vortices are in pure\nSU($N$) gauge theories. Here we report on our investigations of an analogous\nsymmetry in a 2-color model with dynamical Wilson quarks carrying half-integer\nelectric charge.",
        "positive": "cuLGT: Lattice Gauge Fixing on GPUs: We adopt CUDA-capable Graphic Processing Units (GPUs) for Landau, Coulomb and\nmaximally Abelian gauge fixing in 3+1 dimensional SU(3) and SU(2) lattice gauge\nfield theories. A combination of simulated annealing and overrelaxation is used\nto aim for the global maximum of the gauge functional. We use a fine grained\ndegree of parallelism to achieve the maximum performance: instead of the common\n1 thread per site strategy we use 4 or 8 threads per lattice site. Here, we\nreport on an improved version of our publicly available code (www.cuLGT.com and\ngithub.com/culgt) which again increases performance and is much easier to\ninclude in existing code. On the GeForce GTX 580 we achieve up to 470 GFlops\n(utilizing 80% of the theoretical peak bandwidth) for the Landau overrelaxation\ncode."
    },
    {
        "anchor": "Real-time gauge theory simulations from stochastic quantization using\n  optimized updating: Stochastic quantisation is applied to the problem of calculating real-time\nevolution on a Minkowskian space-time lattice. We employ optimized updating\nusing reweighting, or gauge fixing, respectively. These procedures do not\naffect the underlying theory, but strongly improve the stability properties of\nthe stochastic dynamics.",
        "positive": "Constraining $1+\\mathcal{J}\\to 2$ coupled-channel amplitudes in\n  finite-volume: Whether one is interested in accessing the excited spectrum of hadrons or\ntesting the standard model of particle physics, electroweak transition\nprocesses involving multi-hadron channels in the final state play an important\nrole in a variety of experiments. Presently the primary theoretical tool with\nwhich one can study such reactions is lattice QCD, which is defined in a finite\nspacetime volume. In this work, we investigate the feasibility of implementing\nexisting finite-volume formalism in realistic lattice QCD calculation of\nreactions in which a stable hadron can transition to one of several two-hadron\nchannels under the action of an external current. We provide a conceptual\ndescription of the coupled-channel transition formalism, a practical roadmap\nfor carrying out a calculation, and an illustration of the approach using\nsynthetic data for two non-trivial resonant toy models. The results provide a\nproof-of-principle that such reactions can indeed be constrained using\nmodern-day lattice QCD calculations, motivating explicit computation in the\nnear future."
    },
    {
        "anchor": "More on heavy tetraquarks in lattice QCD at almost physical pion mass: We report on our progress in studying exotic, heavy tetraquark states,\n$qq\\prime \\bar Q\\bar Q\\prime$. Using publicly available dynamical $n_f =2+1$\nWilson-Clover gauge configurations, generated by the PACS-CS collaboration,\nwith pion masses $\\simeq$164, 299 and 415 MeV, we extend our previous analysis\nto heavy quark components containing heavier than physical bottom quarks $\\bar\nQ\\bar Q\\prime=\\bar b\\prime\\bar b\\prime$ or $\\bar Q\\bar Q\\prime=\\bar b\\bar\nb\\prime$, charm and bottom quarks $\\bar c\\bar b$ and also only charm quarks\n$\\bar c\\bar c$. Throughout we employ NRQCD and relativistic heavy quarks for\nthe heavier than bottom, bottom and charm quarks. Using our previously\nestablished diquark-antidiquark and meson-meson operator basis we comment in\nparticular on the dependence of the binding energy on the mass of the heavy\nquark component $\\bar Q\\bar Q$, with heavy quarks ranging from $m_Q=0.85\\ldots\n6.3\\cdot m_b$. In the heavy flavor non-degenerate case, $\\bar Q\\bar Q\\prime$,\nand especially for the tetraquark channel $ud\\bar c\\bar b$, we extend our work\nto utilize a $3\\times 3$ GEVP to study the ground and threshold states thereby\nenabling a clear identification of possible binding. Finally, we present\ninitial work on the $\\bar Q\\bar Q\\prime=\\bar c\\bar c$ system where a much\nlarger operator basis is available in comparison to flavor combinations with\nNRQCD quarks.",
        "positive": "Large N QCD on the lattice -- A review of recent results in the\n  fermionic sector: It is possible to numerically solve QCD in the planar limit using standard\nnumerical techniques on existing computer clusters. The basic ideas behind the\ncomputational strategy an recent numerical results in the fermionic sector of\nlarge N QCD are reviewed."
    },
    {
        "anchor": "Lattice study of the Schwinger model at fixed topology: At small lattice spacing QCD simulations are expected to become stuck in a\nsingle topological sector. Observables evaluated in a fixed topological sector\ndiffer from their counterparts in full QCD, i.e. at unfixed topology, by volume\ndependent corrections. We investigate these corrections in the two-flavor\nSchwinger model, which is in several aspects similar to QCD, using Wilson\nfermions. We also try to remove these corrections by suitable extrapolations to\ninfinite volume.",
        "positive": "Towards a lattice determination of the form factors of the rare Hyperon\n  decay $\u03a3^+ \\to p \\ell^+ \\ell^-$: The rare Hyperon decay $\\Sigma^+ \\to p \\ell^+ \\ell^-$ is an $s \\to d$ flavour\nchanging neutral current, and is therefore suppressed in within the Standard\nModel, making it an excellent probe for new physics. The process is dominated\nby long distance processes and therefore lattice QCD is the only existing\ntechnique to obtain a first principles Standard Model theoretical prediction.\nWe present our work on an unphysical exploratory study of the rare Hyperon\ndecay on the lattice, including an investigation into the applicability of\nsource-sink sampling for this decay, and we show a generalisation of the summed\nmethod for arbitrary 3-point functions and 4-point functions. In addition we\nshow preliminary results for a computation of the $s \\to u$ semileptonic\nHyperon decays."
    },
    {
        "anchor": "Nucleon transversity generalized form factors with twisted mass fermions: We present results on the nucleon tensor form factors and first moment of the\ntransversity distribution using maximally twisted mass fermions. We analyze two\nNf=2+1+1 ensembles having pion masses of 213 MeV and 373 MeV with lattice\nspacing a=0.064 fm and a=0.082 fm, respectively. First results using an Nf=2\nensemble of twisted mass fermions with a clover term at a physical pion mass\nand lattice spacing a=0.094 fm are also presented. The renormalization function\nfor the local tensor form factors is evaluated non-perturbatively with a\nperturbative subtraction of O(a^2)-terms, while for the first moment of the\ntransversity we use a perturbative estimate. Results are given in the MS-bar\nscheme at a scale of mu=2 GeV, and are compared with recent results obtained\nusing different discretization schemes.",
        "positive": "Continuous $\u03b2$ function for the SU(3) gauge systems with two and\n  twelve fundamental flavors: The gradient flow transformation can be interpreted as continuous real-space\nrenormalization group transformation if a coarse-graining step is incorporated\nas part of calculating expectation values. The method allows to predict\ncritical properties of strongly coupled systems including the renormalization\ngroup $\\beta$ function and anomalous dimensions at nonperturbative fixed\npoints. In this contribution we discuss a new analysis of the continuous\nrenormalization group $\\beta$ function for $N_f=2$ and $N_f=12$ fundamental\nflavors in SU(3) gauge theories based on this method. We follow the approach\ndeveloped and tested for the $N_f=2$ system in arXiv:1910.06408. Here we\npresent further information on the analysis, emphasizing the robustness and\nintuitive features of the continuous $\\beta$ function calculation. We also\ndiscuss the applicability of the continuous $\\beta$ function calculation in\nconformal systems, extending the possible phase diagram to include a 4-fermion\ninteraction. The numerical analysis for $N_f=12$ uses the same set of ensembles\nthat was generated and analyzed for the step scaling function in\narXiv:1909.05842. The new analysis uses volumes with $L \\ge 20$ and determines\nthe $\\beta$ function in the $c=0$ gradient flow renormalization scheme. The\ncontinuous $\\beta$ function predicts the existence of a conformal fixed point\nand is consistent between different operators. Although determinations of the\nstep scaling and continuous $\\beta$ function use different renormalization\nschemes, they both predict the existence of a conformal fixed point around\n$g^2\\sim 6$."
    },
    {
        "anchor": "Unquenched domain wall quarks with multi-bosons: The numerical simulation of domain wall quarks with the two-step multi-boson\n(TSMB) algorithm is considered. The inclusion of single quark flavours, as\nrequired for strange quarks, is discussed. The usage of computer memory can be\nkept relatively low, independently of the order of polynomial approximations.\nTests are performed with two flavours (N_f=2) of degenerate quarks near the\nN_t=4 thermodynamical cross over.",
        "positive": "Proton Spin Content From Lattice QCD: We calculate the form factor of the quark energy momentum tensor and thereby\nextract the quark orbital angular momentum of the nucleon. The calculation is\ndone on a quenched $16^3 \\times 24$ lattice at $\\beta = 6.0$ and with Wilson\nfermions at $\\kappa$ = 0.148, 0.152, 0.154 and 0.155. We calculate the\ndisconnected insertion stochastically which employs the $Z_2$ noise with an\nunbiased subtraction. This proves to be an efficient method of reduce the error\nfrom the noise. We find that the total quark contribution to the proton spin is\n$0.29 \\pm 0.07$. From this we deduce that the quark orbital angular momentum is\n$0.17 \\pm 0.08$ and predict the gluon spin to be $0.21 \\pm 0.07$, i.e. about\n40% of the proton spin is due to the glue."
    },
    {
        "anchor": "The phase diagram of twisted mass lattice QCD: We use the effective chiral Lagrangian to analyze the phase diagram of\ntwo-flavor twisted mass lattice QCD as a function of the normal and twisted\nmasses, generalizing previous work for the untwisted theory. We first determine\nthe chiral Lagrangian including discretization effects up to next-to-leading\norder (NLO) in a combined expansion in which m_\\pi^2/(4\\pi f_\\pi)^2 ~ a \\Lambda\n(a being the lattice spacing, and \\Lambda = \\Lambda_{QCD}). We then focus on\nthe region where m_\\pi^2/(4\\pi f_\\pi)^2 ~ (a \\Lambda)^2, in which case\ncompetition between leading and NLO terms can lead to phase transitions. As for\nuntwisted Wilson fermions, we find two possible phase diagrams, depending on\nthe sign of a coefficient in the chiral Lagrangian. For one sign, there is an\nAoki phase for pure Wilson fermions, with flavor and parity broken, but this is\nwashed out into a crossover if the twisted mass is non-vanishing. For the other\nsign, there is a first order transition for pure Wilson fermions, and we find\nthat this transition extends into the twisted mass plane, ending with two\nsymmetrical second order points at which the mass of the neutral pion vanishes.\nWe provide graphs of the condensate and pion masses for both scenarios, and\nnote a simple mathematical relation between them. These results may be of\nimportance to numerical simulations.",
        "positive": "Composite operators in lattice QCD: nonperturbative renormalization: We investigate the nonperturbative renormalization of composite operators in\nlattice QCD restricting ourselves to operators that are bilinear in the quark\nfields. These include operators which are relevant to the calculation of\nmoments of hadronic structure functions. The computations are based on Monte\nCarlo simulations using quenched Wilson fermions."
    },
    {
        "anchor": "Phase structure and confinement properties of noncompact gauge theories\n  I: In the context of reviewing noncompact lattice gauge models at zero and\nfinite temperature we study in detail a contribution of the invariant measure\nand the time-like plaquette configurations to correlation functions, analyze\nthe problem of the compactness of the potentials in respect to the confinement\nand indicate the essential features to deal with the Wilson gauge theory in the\nweak coupling region. A method for calculating an effective confining\nnoncompact model is also proposed.",
        "positive": "Studies of Correlations in the Critical Domain of the $SU(2)$\n  Gluodynamics: By considering the example of $SU(2)$ gluodynamics, we check numerically the\nidea that the strong correlation of the Polyakov loop with the longitudinal\ngluon propagator and related quantities can be used to substantially reduce the\nfinite-volume effects as well as to extrapolate in temperature over the\ncritical domain."
    },
    {
        "anchor": "Numerical evidence for monopoles in 3-dimensional Yang-Mills theory: Recently Anishetty, Majumdar and Sharatchandra have proposed a way of\ncharacterizing topologically non-trivial configurations for 2+1 dimensional\nYang-Mills theory in a local and manifestly gauge invariant manner. In this\npaper paper we develop criteria to locate such objects in lattice gauge theory\nand find them in numerical simulations.",
        "positive": "$B_{(s)}\\to D_{(s)}$ semileptonic decays with NRQCD-HISQ valence quarks: We present a calculation of the form factors, $f_0$ and $f_+$, for the\n$B_{(s)} \\to D_{(s)}$ semileptonic decays. Our work uses the MILC $n_f=2+1$\nAsqTad configurations with NRQCD and HISQ valence quarks at four values of the\nmomentum transfer $q^2$. We provide results for the chiral-continuum\nextrapolations of the scalar and vector form factors."
    },
    {
        "anchor": "Precise B, B_s and B_c meson spectroscopy from full lattice QCD: We give the first accurate results for $B$ and $B_s$ meson masses from\nlattice QCD including the effect of $u$, $d$ and $s$ sea quarks, and we improve\nan earlier value for the $B_c$ meson mass. By using the Highly Improved\nStaggered Quark action for $u/d$, $s$ and $c$ quarks and NRQCD for the $b$\nquarks, we are able to achieve an accuracy in the masses of around 10 MeV. Our\nresults are: $m_B$ = 5.291(18) GeV, $m_{B_s}$ = 5.363(11) GeV and $m_{B_c}$ =\n6.280(10) GeV. Note that all QCD parameters here are tuned from other\ncalculations, so these are parameter free tests of QCD against experiment. We\nalso give scalar, $B_{s0}^*$, and axial vector, $B_{s1}$, meson masses. We find\nthese to be slightly below threshold for decay to $BK$ and $B^*K$ respectively.",
        "positive": "Quenched hadron spectroscopy with improved staggered quark action: We investigate light hadron spectroscopy with an improved quenched staggered\nquark action. We compare the results obtained with an improved gauge plus an\nimproved quark action, an improved gauge plus standard quark action, and the\nstandard gauge plus standard quark action. Most of the improvement in the\nspectroscopy results is due to the improved gauge sector. However, the improved\nquark action substantially reduces violations of Lorentz invariance, as\nevidenced by the meson dispersion relations."
    },
    {
        "anchor": "Fit to Gluon Propagator and Gribov Formula: We report a numerical study of SU(2) lattice gauge theory in the minimal\nCoulomb gauge at beta = 2.2 and 9 different volumes. After extrapolation to\ninfinite volume, our fit agrees with a lattice discretization of Gribov's\nformula for the transverse equal-time would-be physical gluon propagator, that\nvanishes like |k| at k = 0, whereas the free equal-time propagator (2|k|)^{-1}\ndiverges. Our fit lends reality to a confinement scenario in which the would-be\nphysical gluons leave the physical spectrum while the long-range Coulomb force\nconfines color.",
        "positive": "Non-perturbative improvement of stout-smeared three flavour clover\n  fermions: We discuss a 3-flavour lattice QCD action with clover improvement in which\nthe fermion matrix has single level stout smearing for the hopping terms\ntogether with unsmeared links for the clover term. With the (tree-level)\nSymanzik improved gluon action this constitutes the Stout Link Non-perturbative\nClover or SLiNC action. To cancel O(a) terms the clover term coefficient has to\nbe tuned. We present here results of a non-perturbative determination of this\ncoefficient using the Schroedinger functional and as a by-product a\ndetermination of the critical hopping parameter. Comparisons of the results are\nmade with lowest order perturbation theory."
    },
    {
        "anchor": "On the distinction between color confinement, and confinement: The property of color confinement (\"C confinement\"), meaning that all\nasymptotic particle states are color neutral, holds not only in QCD, but also\nin gauge-Higgs theories deep in the Higgs regime. In this talk we describe a\nnew and stronger confinement criterion, separation-of-charge confinement or\n\"S$_c$ confinement,\" which is an extension of the Wilson area-law criterion to\ngauge + matter theories. We will show that there is a transition between S$_c$\nand C confinement in the phase plane of gauge-Higgs theories, and we will also\nexplain what symmetry is actually broken in the Higgs phase of a gauge-Higgs\ntheory.",
        "positive": "Electromagnetic and strong isospin-breaking corrections to the muon $g -\n  2$ from Lattice QCD+QED: We present a lattice calculation of the leading-order electromagnetic and\nstrong isospin-breaking corrections to the hadronic vacuum polarization (HVP)\ncontribution to the anomalous magnetic moment of the muon. We employ the gauge\nconfigurations generated by the European Twisted Mass Collaboration (ETMC) with\n$N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a\n\\simeq 0.062, 0.082, 0.089$ fm) with pion masses between $\\simeq 210$ and\n$\\simeq 450$ MeV. The results are obtained adopting the RM123 approach in the\nquenched-QED approximation, which neglects the charges of the sea quarks. Quark\ndisconnected diagrams are not included. After the extrapolations to the\nphysical pion mass and to the continuum and infinite-volume limits the\ncontributions of the light, strange and charm quarks are respectively equal to\n$\\delta a_\\mu^{\\rm HVP}(ud) = 7.1 ~ (2.5) \\cdot 10^{-10}$, $\\delta a_\\mu^{\\rm\nHVP}(s) = -0.0053 ~ (33) \\cdot 10^{-10}$ and $\\delta a_\\mu^{\\rm HVP}(c) =\n0.0182 ~ (36) \\cdot 10^{-10}$. At leading order in $\\alpha_{em}$ and $(m_d -\nm_u) / \\Lambda_{QCD}$ we obtain $\\delta a_\\mu^{\\rm HVP}(udsc) = 7.1 ~ (2.9)\n\\cdot 10^{-10}$, which is currently the most accurate determination of the\nisospin-breaking corrections to $a_\\mu^{\\rm HVP}$."
    },
    {
        "anchor": "Histograms in heavy-quark QCD at finite temperature and density: We study the phase structure of lattice QCD with heavy quarks at finite\ntemperature and density by a histogram method. We determine the location of the\ncritical point at which the first-order deconfining transition in the\nheavy-quark limit turns into a crossover at intermediate quark masses through a\nchange of the shape of the histogram under variation of coupling parameters. We\nestimate the effect of the complex phase factor which causes the sign problem\nat finite density, and show that, in heavy-quark QCD, the effect is small\naround the critical point. We determine the critical surface in 2+1 flavor QCD\nin the heavy-quark region at all values of the chemical potential mu including\nmu=infty.",
        "positive": "Lattice gauge theory studies of the gluon propagator: The gluon propagator in Landau gauge is calculated in quenched QCD on a large\n(32^3X64) lattice at beta=6.0. In order to assess finite volume and finite\nlattice spacing artefacts, we also calculate the propagator on a smaller volume\nfor two different values of the lattice spacing. New structure seen in the\ninfrared region survives conservative cuts to the lattice data, and serves to\nexclude a number of models that have appeared in the literature."
    },
    {
        "anchor": "Microscopic universality in the spectrum of the lattice Dirac operator: Large ensembles of complete spectra of the Euclidean Dirac operator for\nstaggered fermions are calculated for SU(2) lattice gauge theory. The\naccumulation of eigenvalues near zero is analyzed as a signal of chiral\nsymmetry breaking and compared with parameter-free predictions from chiral\nrandom matrix theory. Excellent agreement for the distribution of the smallest\neigenvalue and the microscopic spectral density is found. This provides direct\nevidence for the conjecture that these quantities are universal functions.",
        "positive": "Fermionic effective action and the pahse estructure of non compact\n  quantum electrodynamics in 2+1 dimensions: We study the phase diagram of non compact $QED_3$ using the microcanonical\nfermionic average method described elsewhere. We present evidence for a\ncontinuous phase transition line in the $\\beta, N$ plane, extending down to\narbitrarily small flavour number $N$."
    },
    {
        "anchor": "Perfect 3-Dimensional Lattice Actions for 4-Dimensional Quantum Field\n  Theories at Finite Temperature: We propose a two-step procedure to study the order of phase transitions at\nfinite temperature in electroweak theory and in simplified models thereof. In a\nfirst step a coarse grained free energy is computed by perturbative methods. It\nis obtained in the form of a 3-dimensional perfect lattice action by a block\nspin transformation. It has finite temperature dependent coefficients. In this\nway the UV-problem and the infrared problem is separated in a clean way. In the\nsecond step the effective 3-dimensional lattice theory is treated in a\nnonperturbative way, either by the Feynman-Bogoliubov method (solution of a gap\nequation), by real space renormalization group methods, or by computer\nsimulations. In this paper we outline the principles for $\\varphi ^4$-theory\nand scalar electrodynamics. The Ba{\\l}aban-Jaffe block spin transformation for\nthe gauge field is used. It is known how to extend this transformation to the\nnonabelian case, but this will not be discussed here.",
        "positive": "Lattice theory for nonrelativistic fermions in one spatial dimension: I derive a loop representation for the canonical and grand-canonical\npartition functions for an interacting four-component Fermi gas in one spatial\ndimension and an arbitrary external potential. The representation is free of\nthe \"sign problem\" irrespective of population imbalance, mass imbalance, and to\na degree, sign of the interaction strength. This property is in sharp contrast\nwith the analogous three-dimensional two-component interacting Fermi gas, which\nexhibits a sign problem in the case of unequal masses, chemical potentials, and\nrepulsive interactions. The one-dimensional system is believed to exhibit many\nphenomena in common with its three-dimensional counterpart, including an analog\nof the BCS-BEC crossover, and nonperturbative universal few- and many-body\nphysics at scattering lengths much larger than the range of interaction, making\nthe theory an interesting candidate for numerical study. Positivity of the\nprobability measure for the partition function allows for a mean-field\ntreatment of the model; here, I present such an analysis for the interacting\nFermi gas in the SU(4) (unpolarized, mass-symmetric) limit, and demonstrate\nthat there exists a phase in which a continuum limit may be defined."
    },
    {
        "anchor": "Maximal twist and the spectrum of quenched twisted mass lattice QCD: Results on the hadron masses for a degenerate doublet of up and down quarks\nfrom quenched twisted mass lattice QCD at maximal twist are presented. Two\ndefinitions of maximal twist are used and the hadron masses for these\ndefinitions are compared. Mass splittings within the Delta(1232) multiplet due\nto flavor breaking effects are discussed.",
        "positive": "Panel discussion on chiral extrapolation of physical observables: This is an approximate reconstruction of the panel discussion on chiral\nextrapolation of physical observables. The session consisted of brief\npresentations from panelists, followed by responses from the panel, and\nconcluded with questions and comments from the floor with answers from\npanelists. In the following, the panelists have summarized their statements,\nand the ensuing discussion has been approximately reconstructed from notes."
    },
    {
        "anchor": "Energies of B_s meson excited states - a lattice study: This is a follow-up to our earlier work on the energies and radial\ndistributions of heavy-light mesons. The heavy quark is taken to be static\n(infinitely heavy) and the light quark has a mass about that of the strange\nquark. We now concentrate on the energies of the excited states with higher\nangular momentum and with a radial node. A new improvement is the use of\nhypercubic blocking in the time direction.\n  The calculation is carried out with dynamical fermions on a 16 cubed times 32\nlattice with a lattice spacing approximately 0.1 fm generated using a\nnon-perturbatively improved clover action.\n  In nature the closest equivalent of this heavy-light system is the B_s meson,\nwhich allows us to compare our lattice calculations to experimental results\n(where available) or to give a prediction where the excited states,\nparticularly P-wave states, should lie. We pay special attention to the\nspin-orbit splitting, to see which one of the states (for a given angular\nmomentum L) has the lower energy. An attempt is made to understand these\nresults in terms of the Dirac equation.",
        "positive": "Wilson fermion doubling phenomenon on irregular lattice: the similarity\n  and difference with the case of regular lattice: It is shown that the Wilson fermion doubling phenomenon on irregular lattices\n(simplicial complexes) does exist. This means that the irregular (not smooth)\nzero or soft modes exist. The statement is proved on 4 Dimensional lattice by\nmeans of the Atiyah-Singer index theorem, then it is extended easily into the\ncases $D<4$. But there is a fundamental difference between doubled quanta on\nregular and irregular lattices: in the latter case the propagator decreases\nexponentially. This means that the doubled quanta on irregular lattice are\n\"bad\" quasiparticles."
    },
    {
        "anchor": "Investigating the sign problem for two-dimensional $\\mathcal{N}=(2,2)$\n  and $\\mathcal{N}=(8,8)$ lattice super Yang--Mills theories: Recently there has been some controversy in the literature concerning the\nexistence of a fermion sign problem in the $\\mathcal{N}=(2,2)$ supersymmetric\nYang--Mills (SYM) theories on the lattice. In this work, we address this issue\nby conducting Monte Carlo simulations not only for $\\mathcal{N}=(2,2)$ but also\nfor $\\mathcal{N}=(8,8)$ SYM in two dimensions for the U(N) theories with N=2,\nusing the new ideas derived from topological twisting followed by geometric\ndiscretization. Our results from simulations provide the evidence that these\ntheories do {\\it not} suffer from a sign problem as the continuum limit is\napproached. These results thus boost confidence that these new lattice\nformulations can be used successfully to explore the nonperturbative aspects of\nthe four-dimensional $\\mathcal{N}=4$ SYM theory.",
        "positive": "Partial Wave Mixing in Hamiltonian Effective Field Theory: The spectrum of excited states observed in the finite volume of lattice QCD\nis governed by the discrete symmetries of the cubic group. This finite group\npermits the mixing of orbital angular momentum quanta in the finite volume. As\nexperimental results refer to specific angular momentum in a partial-wave\ndecomposition, a formalism mapping the partial-wave scattering potentials to\nthe finite volume is required. This formalism is developed herein for\nHamiltonian effective field theory, an extension of chiral effective field\ntheory incorporating the L\\\"uscher relation linking the energy levels observed\nin finite volume to the scattering phase shift. The formalism provides an\noptimal set of rest-frame basis states maximally reducing the dimension of the\nHamiltonian, and it should work in any Hamiltonian formalism. As a first\nexample of the formalism's implementation, lattice QCD results for the spectrum\nof an isospin-2 $\\pi\\pi$ scattering system are analyzed to determine the $s$,\n$d$, and $g$ partial-wave scattering information."
    },
    {
        "anchor": "The spectrum of an SU(3) gauge theory with a fundamental Higgs field: In gauge theories, the physical, experimentally observable spectrum consists\nonly of gauge-invariant states. This spectrum can be different from the\nelementary spectrum even at weak coupling and in the presence of the\nBrout-Englert-Higgs effect. We demonstrate this for an SU(3) gauge theory with\na single fundamental Higgs, a toy theory for grand-unified theories. The\nmanifestly gauge-invariant approach of lattice gauge theory is used to\ndetermine the spectrum in four different channels. It is found to be\nqualitatively different from the elementary one, and especially from the one\npredicted by standard perturbation theory. The result can be understood in\nterms of the Froehlich-Morchio-Strocchi mechanism. In fact, we find that\nanalytic methods based on this mechanism, a gauge-invariant extension of\nperturbation theory, correctly determines the spectrum, and gives already at\nleading order a reasonably good quantitative description. Together with\nprevious results this supports that this approach is the analytic method of\nchoice for theories with a Brout-Englert-Higgs effect.",
        "positive": "Running coupling constant of ten-flavor QCD with the Schr\u00f6dinger\n  functional method: Walking technicolor theory attempts to realize electroweak symmetry breaking\nas the spontaneous chiral symmetry breakdown caused by the gauge dynamics with\nslowly varying gauge coupling constant and large mass anomalous dimension.\nMany-flavor QCD is one of the candidates owning these features. We focus on the\nSU(3) gauge theory with ten flavors of massless fermions in the fundamental\nrepresentation, and compute the gauge coupling constant in the Schr\\\"odinger\nfunctional scheme. Numerical simulation is performed with $O(a)$-unimproved\nlattice action, and the continuum limit is taken in linear in lattice spacing.\nWe observe evidence that this theory possesses an infrared fixed point."
    },
    {
        "anchor": "Conundrums at Finite Density: Extending the successes of lattice quantum chromodynamics(QCD) at zero as\nwell as nonzero temperatures to nonzero density is extremely desirable in view\nof the quest for the QCD phase diagram both theoretically and experimentally.\nIt turns out though to give rise to some conundrums whose resolution may assist\nprogress in this exciting but difficult area, and should therefore be sought\nactively.",
        "positive": "Higher partial wave contamination in finite-volume formulae for 1-to-2\n  transitions: It is common practice to truncate the finite-volume formula for $K\\to\\pi\\pi$,\nand other one-to-two transitions, to only include the lowest partial wave, as\nin the original derivation by Lellouch and L\\\"uscher. However, as the precision\nof lattice calculations increases, it may become important to asses the\nsystematic effect of this approximation. With this motivation, we compare the\n$S$-wave-only ($\\ell=0$) results with those truncated at the next lowest value\nof angular momentum."
    },
    {
        "anchor": "QCD Thermodynamics with Three Flavors of Improved Staggered Quarks: We report on a study of QCD thermodynamics with three flavors of quarks,\nusing a Symanzik improved gauge action and the Asqtad O(a^2) improved staggered\nquark action. Simulations were carried out with lattice spacings 1/4T, 1/6T and\n1/8T both for three degenerate quarks with masses less than or equal to the\nstrange quark mass, m_s, and for degenerate up and down quarks with masses in\nthe range 0.1 m_s \\leq m_{u,d} \\leq 0.6 m_s, and the strange quark mass fixed\nnear its physical value. We present results for standard thermodynamics\nquantities, such as the Polyakov loop, the chiral order parameter and its\nsusceptibility. For the quark masses studied to date we find a rapid crossover\nrather than a bona fide phase transition. We have carried out the first\ncalculations of quark number susceptibilities with three flavors of sea quarks.\nThese quantities are of physical interest because they are related to\nevent-by-event fluctuations in heavy ion collision experiments. Comparison of\nsusceptibilities at different lattice spacings show that our results are close\nto the continuum values.",
        "positive": "Full QCD calculation of neutron electric dipole moment with the external\n  electric field method: We have calculated the neutron electric dipole moment (NEDM) in the presence\nof the CP violating $\\theta$ term in lattice QCD with 2-flavor dynamical clover\nquarks, using the external electric field method. Accumulating a large number\nof statistics by the averages over 16 different source points and over forward\nand backward nucleon propagators, we have obtained non-zero signals of neutron\nand proton EDM beyond one standard deviation at each quark mass in full QCD. We\nhave investigated the quark mass dependence of nucleon EDM in full QCD, and\nhave found that nucleon EDM in full QCD does not decrease toward the chiral\nlimit, as opposed to the theoretical expectation. We briefly discuss possible\nreasons for this behavior."
    },
    {
        "anchor": "2+1 flavor QCD simulation on a $96^4$ lattice: We generate $2+1$ flavor QCD configurations near the physical point on a\n$96^4$ lattice employing the 6-APE stout smeared Wilson clover action with a\nnonperturbative $c_{\\rm SW}$ and the Iwasaki gauge action at $\\beta=1.82$. The\nphysical point is estimated based on the chiral perturbation theory using\nseveral data points generated by the reweighting technique from the simulation\npoint, wherer $m_\\pi$,$m_K$ and $m_\\Omega$ are used as physical inputs. The\nphysics results include the quark masses, the hadron spectrum, the pseudoscalar\nmeson decay constants and nucleon sigma terms, using the nonperturbative\nrenormalization factors evaluated with the Schrodinger functional method.",
        "positive": "Comment on ``Savvidy Ferromagnetic Vacuum in Three-Dimensional Latice\n  Gauge Theory'': We analyze SU(2) gauge theory in a constant chromomagnetic field in three\ndimensions. Our analysis instead of supporting the existence of a non-trivial\nminimum in the effective potential, corroborates the evidence of the unstable\nmodes on the lattice."
    },
    {
        "anchor": "Applying Integrability to Gauge Theories: Lattice Yang-Mills theories in any dimension may be regarded as coupled\n1+1-dimensional integrable field theories. These integrable systems decouple at\nlarge center-of-mass energies, where the action becomes effectively\nanisotropic. This effective action is the high-energy center-of-mass limit of\nthe gauge theory. In 2+1 dimensions, the quark-antiquark potential and the mass\nspectrum can be calculated, using the exact 1+1-dimensional S-matrix and form\nfactors. The methods are quite similar to those applying integrability in\nstatistical and condensed-matter physics. The high-energy anisotropic action at\none loop in 3+1 dimensions has been found using a Wilsonian renormalization\nmethod. We briefly discuss the isotropic theory in 2+1 dimensions and the\nconnection with soft scattering in 3+1 dimensions.",
        "positive": "Towards a non-perturbative calculation of Weak Hamiltonian Wilson\n  coefficients: We propose a method to compute the Wilson coefficients of the weak effective\nHamiltonian to all orders in the strong coupling constant using Lattice QCD\nsimulations. We perform our calculations adopting an unphysically light weak\nboson mass of around $2~\\mathrm{GeV}$. We demonstrate that systematic errors\nfor the Wilson coefficients $C_1$ and $C_2$, related to the current-current\nfour-quark operators, can be controlled and present a path towards precise\ndeterminations in subsequent works."
    },
    {
        "anchor": "New Noise Subtraction Methods in Lattice QCD: Noise subtraction techniques can help reduce the statistical uncertainty in\nthe extraction of hard to detect signals. We describe new noise subtraction\nmethods in Lattice QCD which apply to disconnected diagram evaluations. Some of\nthe noise suppression techniques include polynomial quark matrix methods,\neigenspectrum deflation methods, and combination methods. Our most promising\ntechnique combines polynomial and Hermitian deflation subtraction methods. The\noverall goal is to improve the efficiency of Lattice QCD noise method\nalgorithms.",
        "positive": "Lattice QED in external electromagnetic fields: We study QED in external electromagnetic fields using methods developed for\nsimulating lattice QCD. Our first project is to simulate QED in a constant (in\nspace and time) external magnetic field on a euclidean space-time lattice using\nthe Rational Hybrid Monte Carlo (RHMC) method. Observables we measure include\nthe condensate $\\langle\\bar{\\psi}\\psi\\rangle$ and the effective electron action\nafter integrating out the fermion fields. We look for evidence that the\ncombined effect of the magnetic field and the electron-positron attraction from\nQED produces a non-zero condensate in the limit of zero electron mass, a\nnon-perturbative effect analogous to spontaneous chiral symmetry breaking. Very\npreliminary evidence is that such a condensate exists, at least for strong\nexternal magnetic fields and unphysically large electric charge. In addition,\nwe are storing field configurations to measure the expected distortions and\nscreenings of the coulomb field of a charged particle due to the vacuum\npolarization asymmetries produced by the magnetic field. We hope also to\nmeasure the dynamical contribution to the electron mass produced by the same\nmechanism that produces a finite condensate in the zero input mass limit."
    },
    {
        "anchor": "J/\u03a8at high temperatures in anisotropic lattice QCD: J/\\Psi and \\eta_c above the QCD critical temperature T_c are studied in\nanisotropic quenched lattice QCD, considering whether the c\\bar c systems above\nT_c are compact quasi-bound states or scattering states. We adopt the standard\nWilson gauge action and O(a)-improved Wilson quark action with renormalized\nanisotropy a_s/a_t =4 at \\beta=6.10 on 16^3\\times (14-26) lattices, which\ncorrespond to the spatial lattice volume V\\equiv L^3\\simeq(1.55{\\rm fm})^3 and\ntemperatures T\\simeq(1.11-2.07)T_c. To clarify whether compact charmonia\nsurvive in the deconfinement phase, we investigate spatial boundary-condition\ndependence of the energy of the c\\bar c systems above T_c. In fact, for\nlow-lying c \\bar c scattering states, there appears a significant energy\ndifference \\Delta E \\equiv E{\\rm (APBC)}-E{\\rm (PBC)} between periodic and\nanti-periodic boundary conditions as \\Delta\nE\\simeq2\\sqrt{m_c^2+3\\pi^2/L^2}-2m_c (m_c: charm quark mass) on the\nfinite-volume lattice. In contrast, for compact charmonia, there is no\nsignificant energy difference between periodic and anti-periodic boundary\nconditions. As a lattice QCD result, we find almost no spatial\nboundary-condition dependence for the energy of the c\\bar c system in J/\\Psi\nand \\eta_c channels for T\\simeq(1.11-2.07)T_c, which indicates that J/\\Psi and\n\\eta_c would survive as compact c\\bar c quasi-bound states below 2T_c.",
        "positive": "Analytical Relation between Quark Confinement and Chiral Symmetry\n  Breaking in QCD: We study the relation between quark confinement and spontaneous\nchiral-symmetry breaking directly in QCD. In lattice QCD formalism, we derive\nan analytical gauge-invariant relation between the Polyakov loop $\\langle L_P\n\\rangle$ and the Dirac eigenvalues $\\lambda_n$, i.e., $\\langle L_P \\rangle\n\\propto \\sum_n \\lambda_n^{N_t -1} \\langle n|\\hat U_4|n \\rangle$, on a\ntemporally odd-number lattice, where the temporal lattice size $N_t$ is odd.\nHere, $|n \\rangle$ denotes the Dirac eigenmode, i.e., $\\not D|n\n\\rangle=i\\lambda_n|n \\rangle$, and $\\hat U_4$ the temporal link-variable\noperator. We here use an ordinary square lattice with the normal periodic\nboundary condition for link-variables $U_\\mu(s)$ in the temporal direction.\nBecause of the factor $\\lambda_n^{N_t -1}$ in the analytical relation, the\ncontribution of low-lying Dirac modes to the Polyakov loop is negligibly small\nin both confined and deconfined phases, while the low-lying Dirac modes are\nessential for chiral symmetry breaking. Also, in lattice QCD simulations, we\nnumerically confirm the analytical relation, non-zero finiteness of $\\langle\nn|\\hat U_4|n \\rangle$ for each Dirac mode, and negligibly small contribution of\nlow-lying Dirac modes to the Polyakov loop. Thus, we conclude that low-lying\nDirac modes are not essential for confinement, which indicates no direct\none-to-one correspondence between confinement and chiral symmetry breaking in\nQCD."
    },
    {
        "anchor": "Critical Behaviour of the Two Dimensional Step Model: We use finite--size scaling of Lee--Yang partition function zeroes to study\nthe critical behaviour of the two dimensional step or sgn $O(2)$ model. We\npresent evidence that, like the closely related $XY$--model, this has a phase\ntransition from a disordered high temperature phase to a low temperature\nmassless phase where the model remains critical. The critical parameters\n(including logarithmic corrections) are compatible with those of the\n$XY$--model indicating that both models belong to the same universality class.",
        "positive": "A fresh look on the flux tube in Abelian-projected SU(2) gluodynamics: We reconsider the properties of the $Q\\bar{Q}$ flux tube within\nAbelian-projected SU(2) lattice gauge theory in terms of electric field and\nmonopole current. In the maximal Abelian gauge we assess the influence of the\nGribov copies on the apparent flux-tube profile. For the optimal gauge fixing\nwe study the independence of the profile on the lattice spacing for $\\beta=$\n2.3, 2.4, and 2.5115 on a $32^4$ lattice. We decompose the Abelian Wilson loop\ninto monopole and photon parts and compare the electric and monopole profile\nemerging from different sources with the field strength and monopole current\nwithin the dual Ginzburg-Landau theory."
    },
    {
        "anchor": "Renormalized Polyakov loops in many representations: We present a renormalization procedure for Polyakov loops which explicitly\nimplements the fact that the renormalization constant depends only on the\nultraviolet cutoff. Using this we study the renormalized Polyakov loops in all\nrepresentations upto the {\\bf 27} of the gauge group SU(3). We find good\nevidence for Casimir scaling of the Polyakov loops and for approximate large-N\nfactorization. By studying many loops together, we are able to show that there\nis a matrix model with a single coupling which can describe the high\ntemperature phase of QCD, although it is hard to construct explicitly. We\npresent the first results for the non-vanishing renormalized octet loop in the\nthermodynamic limit below the SU(3) phase transition, and estimate the\nassociated string breaking distance and the gluelump binding energy. By\nstudying the connection of the direct renormalization procedure with a\ngeneralization of an earlier suggestion which goes by the name of the $Q\\bar Q$\nrenormalization procedure, we find that they are functionally equivalent.",
        "positive": "FLAG: Lattice QCD Tests of the Standard Model and Foretaste for Beyond: After a short presentation of the FLAG collaboration, we review lattice\nresults related to pion, $K$-, $D$- and $B$-meson physics with the aim of\nmaking them easily accessible to the particle-physics community. Only a\nselection of FLAG averages or estimates is presented. For light flavours, we\npresent results on the form factor $f_+(0)$, arising in semileptonic $K\n\\rightarrow \\pi$ transition at zero momentum transfer, as well as the\ndecay-constants $f_K,f_\\pi$ and their ratio. The consequences of these results\nfor the CKM matrix elements $|V_{us}|$ and $|V_{ud}|$ are discussed. For heavy\nflavours we focus on $D$- and $B$-meson decay constants and form factors, as\nwell as the CKM matrix elements $|V_{cs}|$, $|V_{cd}|$ and $|V_{ub}|$. In\naddition we briefly cover the recent advances stemming from the calculation the\n$B_K$-parameters and touch upon related current results relevant to the Physics\nbeyond the Standard Model, which will be the subject of the next FLAG edition."
    },
    {
        "anchor": "Flavor physics and lattice quantum chromodynamics: The course begins with an introduction to the Standard Model, viewed as an\neffective field theory. Experimental and theoretical limits on the energy\nscales at which New Physics can appear, as well as current constraints on quark\nflavor parameters, are reviewed. The role of lattice QCD in obtaining these\nconstraints is described. A second section is devoted to explaining the\nCabibbo-Kobayashi-Maskawa mechanism for quark flavor mixing and CP violation,\nand to detailing its most salient features. The third section is dedicated to\nthe study of K -> pi pi decays. It comprises discussions of indirect CP\nviolation through K^0-\\bar K^0 mixing, of the \\Delta I=1/2 rule and of direct\nCP violation. It presents some of the lattice QCD tools required to describe\nthese phenomena ab initio.",
        "positive": "A Critique of the Link Approach to Exact Lattice Supersymmetry: We examine the link approach to constructing a lattice theory of N=2 super\nYang Mills theory in two dimensions. The goal of this construction is to\nprovide a discretization of the continuum theory which preserves all\nsupersymmetries at non-zero lattice spacing. We show that this approach suffers\nfrom an inconsistency and argue that a maximum of just one of the\nsupersymmetries can be implemented on the lattice."
    },
    {
        "anchor": "On the eta-invariant in the 4D chiral U(1) theory: In contrast to its counterpart in a vector theory, the effective action of a\nchiral gauge theory may have a non-vanishing imaginary part. It consists of the\nso-called Chern-Simons form, which encodes the anomaly and a gauge invariant\npiece related to the eta-invariant of some extended Dirac operator. We\ninvestigate the imaginary part of the effective action in the 4D chiral U(1)\ntheory within the continuum fermion approach. Perturbative analysis indicates\nin general a non-vanishing imaginary part of the effective action. However,\nafter anomaly cancellation we find only a small value of the imaginary part for\nthe investigated configurations.",
        "positive": "A lattice calculation of the hadronic vacuum polarization contribution\n  to $(g-2)_\u03bc$: We present results of calculations of the hadronic vacuum polarisation\ncontribution to the muon anomalous magnetic moment. Specifically, we focus on\ncontrolling the infrared regime of the vacuum polarisation function. Our\nresults are corrected for finite-size effects by combining the Gounaris-Sakurai\nparameterisation of the timelike pion form factor with the L\\\"uscher formalism.\nThe impact of quark-disconnected diagrams and the precision of the scale\ndetermination is discussed and included in our final result in two-flavour QCD,\nwhich carries an overall uncertainty of 6%. We present preliminary results\ncomputed on ensembles with $N_f=2+1$ dynamical flavours and discuss how the\nlong-distance contribution can be accurately constrained by a dedicated\nspectrum calculation in the iso-vector channel."
    },
    {
        "anchor": "Non-Perturbative versus Perturbative Renormalization of Lattice\n  Operators: Our objective is to compute the moments of the deep-inelastic structure\nfunctions of the nucleon on the lattice. A major source of uncertainty is the\nrenormalization of the lattice operators that enter the calculation. In this\ntalk we compare the renormalization constants of the most relevant twist-two\nbilinear quark operators which we have computed non-perturbatively and\nperturbatively to one loop order. Furthermore, we discuss the use of tadpole\nimproved perturbation theory.",
        "positive": "Results on the heavy-dense QCD phase diagram using complex Langevin: Complex Langevin simulations have been able to successfully reproduce results\nfrom Monte Carlo methods in the region where the sign problem is mild and make\npredictions when it is exponentially hard. We present here our study of the QCD\nphase diagram and the boundary between the confined and deconfined phases in\nthe limit of heavy and dense quarks (HDQCD) for 3 different lattice volumes. We\nalso briefly discuss instabilities encountered in our simulations."
    },
    {
        "anchor": "Hypercubic Random Surfaces with Extrinsic Curvature: We analyze a model of hypercubic random surfaces with an extrinsic curvature\nterm in the action. We find a first order phase transition at finite coupling\nseparating a branched polymer from a stable flat phase.",
        "positive": "Exact Lattice Supersymmetry: the Two-Dimensional N=2 Wess-Zumino Model: We study the two-dimensional Wess-Zumino model with extended N=2\nsupersymmetry on the lattice. The lattice prescription we choose has the merit\nof preserving {\\it exactly} a single supersymmetric invariance at finite\nlattice spacing $a$. Furthermore, we construct three other transformations of\nthe lattice fields under which the variation of the lattice action vanishes to\n$O(ga^2)$ where $g$ is a typical interaction coupling. These four\ntransformations correspond to the two Majorana supercharges of the continuum\ntheory. We also derive lattice Ward identities corresponding to these exact and\napproximate symmetries. We use dynamical fermion simulations to check the\nequality of the massgaps in the boson and fermion sectors and to check the\nlattice Ward identities. At least for weak coupling we see no problems\nassociated with a lack of reflection positivity in the lattice action and find\ngood agreement with theory. At strong coupling we provide evidence that\nproblems associated with a lack of reflection positivity are evaded for small\nenough lattice spacing."
    },
    {
        "anchor": "Analytical relation between confinement and chiral symmetry breaking in\n  terms of Polyakov loop and Dirac eigenmodes in odd-number lattice QCD: In lattice QCD formalism, we derive an analytical gauge-invariant relation\nbetween the Polyakov loop $\\langle L_P \\rangle$ and the Dirac eigenvalues\n$\\lambda_n$ in QCD, i.e., $\\langle L_P \\rangle \\propto \\sum_n \\lambda_n^{N_t\n-1} \\langle n|\\hat U_4|n \\rangle$, by considering ${\\rm Tr}\n(\\hat{U}_4\\hat{\\not{D}}^{N_t-1})$ on a temporally odd-number lattice, where the\ntemporal lattice size $N_t$ is odd. This formula is a Dirac spectral\nrepresentation of the Polyakov loop in terms of Dirac eigenmodes $|n\\rangle$.\nWe here use an ordinary square lattice with the normal (nontwisted) periodic\nboundary condition for link-variables $U_\\mu(s)$ in the temporal direction.\nFrom this relation, one can estimate each contribution of the Dirac eigenmode\nto the Polyakov loop. Because of the factor $\\lambda_n^{N_t -1}$ in the Dirac\nspectral sum, this analytical relation generally indicates quite small\ncontribution of low-lying Dirac modes to the Polyakov loop in both confined and\ndeconfined phases, while the low-lying Dirac modes are essential for chiral\nsymmetry breaking. Also in lattice QCD calculations in confined and deconfined\nphases, we numerically confirm the analytical relation, non-zero finiteness of\n$\\langle n|\\hat U_4|n \\rangle$ for each Dirac mode, and negligibly small\ncontribution of low-lying Dirac modes to the Polyakov loop, i.e., the Polyakov\nloop is almost unchanged even by removing low-lying Dirac-mode contribution\nfrom the QCD vacuum generated by lattice QCD simulations. Thus, we conclude\nthat low-lying Dirac modes are not essential modes for confinement, which\nindicates no direct one-to-one correspondence between confinement and chiral\nsymmetry breaking in QCD.",
        "positive": "Nucleon-pion-state contribution in lattice calculations of the nucleon\n  charges $g_A,g_T$ and $g_S$: We employ leading order covariant chiral perturbation theory to compute the\nnucleon-pion-state contribution to the 3-point correlation functions one\ntypically measures in lattice QCD to extract the isovector nucleon charges\n$g_A,g_T$ and $g_S$. We estimate the impact of the nucleon-pion-state\ncontribution on both the plateau and the summation method for lattice\nsimulations with physical pion masses. The nucleon-pion-state contribution\nresults in an overestimation of all charges with both methods. The\noverestimation is roughly equal for the axial and the tensor charge, and about\nfifty percent larger for the scalar charge."
    },
    {
        "anchor": "B-physics from Lattice Gauge Theory: We discuss the main issues in dealing with heavy quarks on the lattice and\nshortly present the different approaches used. We discuss a selection of\ncomputations covering first the b-quark mass and the B(s) meson decay constants\nas the consolidated results (neglecting isospin breaking corrections). In the\nsecond part we consider recent calculations of form factors for tree-level\nsemileptonic decays with emphasis on the tensions between the results produced\nby different collaborations. We propose benchmark quantities and tests suited\nto investigate the origin of such tensions. Finally, we review computations of\nthe bag parameters parameterising neutral meson mixing and provide an overview\non a few recent developments in the field.",
        "positive": "Nature of chiral phase transition in two-flavor QCD: We investigate the nature of the chiral phase transition in the massless\ntwo-flavor QCD using the renormalization group improved gauge action and the\nWilson quark action on $32^3\\times 16$, $24^3\\times 12$, and $16^3\\times 8$\nlattices. We calculate the spacial and temporal propagators of the iso-triplet\nmesons in the pseudo-scalar ($PS$), scalar ($S$), vector ($V$) and axial-vector\n($AV$) channels on the lattice of three sizes. We first verify that the RG\nscaling is excellently satisfied for all cases. This is consistent with the\nclaim that the chiral phase transition is second order. Then we compare the\nspacial and temporal effective masses between the axial partners, i.e. $PS$ vs\n$S$ and $V$ vs $AV$, on each of the three size lattices. We find the effective\nmasses of all of six cases for the axial partners agree remarkably. This is\nconsistent with the claim that at least $Z_4$ subgroup of the $U_A(1)$ symmetry\nin addition to the $SU_A(2)$ symmetry is recovered at the chiral phase\ntransition point."
    },
    {
        "anchor": "Dirac Eigenmodes in an Environment of Dynamical Fermions: We discuss some properties of zero and near-zero modes of the Dirac operator,\nas observed in a recent simulation of 2-flavor QCD. The quarks have been\nimplemented with the so-called Chirally Improved Dirac operator, which obeys\nthe Ginsparg-Wilson relation to a good approximation. We present geometrical\nand statistical properties of these eigenmodes and eigenvalues.",
        "positive": "The confined-deconfined Interface Tension and the Spectrum of the\n  Transfer Matrix: The reduced tension $\\sigma_{cd}$ of the interface between the confined and\nthe deconfined phase of $SU(3)$ pure gauge theory is related to the finite size\neffects of the first transfer matrix eigenvalues. A lattice simulation of the\ntransfer matrix spectrum at the critical temperature $T_c = 1/L_t$ yields\n$\\sigma_{cd} = 0.139(4) T_c^2$ for $L_t = 2$. We found numerical evidence that\nthe deconfined-deconfined domain walls are completely wet by the confined\nphase, and that the confined-deconfined interfaces are rough."
    },
    {
        "anchor": "On the dependence of the gauge-invariant field-strength correlators in\n  QCD on the shape of the Schwinger string: We study, by numerical simulations on a lattice, the dependence of the\ngauge-invariant two-point field-strength correlators in QCD on the path used to\nperform the color parallel transport between the two points.",
        "positive": "Baryon Density Correlations in High Temperature Hadronic Matter: As part of an ongoing effort to characterize the high temperature phase of\nQCD, in a numerical simulation using the staggered fermion scheme, we measure\nthe quark baryon density in the vicinity of a fixed test quark at high\ntemperature and compare it with similar measurements at low temperature and at\nthe crossover temperature. We find an extremely weak correlation at high\ntemperature, suggesting that small color singlet clusters are unimportant in\nthe thermal ensemble. We also find that at $T = 0.75\\ T_c$ the total induced\nquark number shows a surprisingly large component attributable to baryonic\nscreening. A companion simulation of a simple flux tube model produces similar\nresults and also suggests a plausible phenomenological scenario: As the\ncrossover temperature is approached from below, baryonic states proliferate.\nAbove the crossover temperature the mean size of color singlet clusters grows\nexplosively, resulting in an effective electrostatic deconfinement."
    },
    {
        "anchor": "Pion mass difference from vacuum polarization: We calculate the electromagnetic contribution to the pion mass difference,\n$\\Delta m^2_\\pi=m^2_{\\pi^+}-m^2_{\\pi^0}$, in the chiral limit through the\n$VV-AA$ type vacuum polarization using Das-Guralnik-Mathur-Low-Young (DGMLY)\nsum rule. The calculation is made with two-flavors of dynamical overlap\nfermions on a $16^3\\times 32$ lattice at $a\\sim$0.12 fm. The exact chiral\nsymmetry of the overlap fermion is essential to control the systematic error in\nthe difference $VV-AA$. We obtain $\\Delta m_\\pi^2 = 1024(100) {\\rm MeV^2}$\ncombining the lattice data with the perturbative contribution in the high\nmomentum region evaluated by the operator product expansion. By analyzing the\nmomentum dependence of the vacuum polarization, we also obtain pion decay\nconstant $f_\\pi$ and the low-energy constants $L_{10}^r$ in the chiral limit.",
        "positive": "Two-Dimensional Wess-Zumino Models at Intermediate Couplings: We consider the two-dimensional N=(2,2) Wess-Zumino model with a cubic\nsuperpotential at weak and intermediate couplings. Refined algorithms allow for\nthe extraction of reliable masses in a region where perturbation theory no\nlonger applies. We scrutinize the Nicolai improvement program which is supposed\nto guarantee lattice supersymmetry and compare the results for ordinary and\nnon-standard Wilson fermions with those for SLAC derivatives. It turns out that\nthis improvement completely fails to enhance simulations for Wilson fermions\nand only leads to better results for SLAC fermions. Furthermore, even without\nimprovement terms the models with all three fermion species reproduce the\ncorrect values for the fermion masses in the continuum limit."
    },
    {
        "anchor": "Curved domain-wall fermions: We consider fermion systems on a square lattice with a mass term having a\ncurved domain-wall. Similarly to the conventional flat domain-wall fermions,\nmassless and chiral edge states appear on the wall. In the cases of $S^1$ and\n$S^2$ domain-walls embedded into flat hypercubic lattices, we find that these\nedge modes feel gravity through the induced Spin or Spin$^c$ connections. The\ngravitational effect is encoded in the Dirac eigenvalue spectrum as a gap from\nzero. In the standard continuum extrapolation of the square lattice, we find a\ngood agreement with the analytic prediction in the continuum theory. We also\nfind that the rotational symmetry of the edge modes is automatically recovered\nin the continuum limit.",
        "positive": "Suppression of the negative sign problem in quantum Monte Carlo: We present a new Monte Carlo algorithm for simulating quantum spin systems\nwhich is able to suppress the negative sign problem. This algorithm has only a\nlinear complexity in the lattice size used for the simulation. A general\ndescription and a rigorous proof of its correctness is given. Its efficiency is\ntested on a simple 2-dimensional fermionic model. For this model we show that\nour algorithm eliminates the sign problem."
    },
    {
        "anchor": "Fluctuation effects on QCD phase diagram at strong coupling: We study the QCD phase diagram away from the strong coupling limit (SCL) with\nfluctuation effects in the auxiliary field Monte-Carlo (AFMC) method. First, we\ngive an effective action which contains next-to-leading order (NLO) finite\ncoupling effects of the strong coupling expansion as well as fluctuation\neffects. Second, we examine NLO effects of the strong coupling expansion in\nAFMC at zero quark density. We find that the chiral condensate is reduced by\nboth NLO terms from temporal plaquettes and fluctuation effects, and almost no\ndependence on NLO terms from spatial plaquettes in the current analysis. These\nbehaviors can be understood from the modification of the mass and the wave\nfunction renormalization factor by auxiliary fields as in the mean field\nanalysis and the fluctuation effects in the strong coupling limit.",
        "positive": "Fighting topological freezing in the two-dimensional CP$^{N-1}$ model: We perform Monte Carlo simulations of the CP$^{N-1}$ model on the square\nlattice for $N=10$, $21$, and $41$. Our focus is on the severe slowing down\nrelated to instantons. To fight this problem we employ open boundary conditions\nas proposed by L\\\"uscher and Schaefer for lattice QCD. Furthermore we test the\nefficiency of parallel tempering in a line defect. Our results for open\nboundary conditions are consistent with the expectation that topological\nfreezing is avoided, while autocorrelation times are still large. The results\nobtained with parallel tempering are encouraging."
    },
    {
        "anchor": "Charmonium $\u03c7_{c0}$ and $\u03c7_{c2}$ resonances in coupled-channel\n  scattering from lattice QCD: In order to explore the spectrum of hidden-charm scalar and tensor\nresonances, we study meson-meson scattering with $J^{PC}=0^{++}, 2^{++}$ in the\ncharmonium energy region using lattice QCD. Employing a light-quark mass\ncorresponding to $m_\\pi \\approx 391$ MeV, we determine coupled-channel\nscattering amplitudes up to around 4100 MeV considering all kinematically\nrelevant channels consisting of a pair of open-charm mesons or a charmonium\nmeson with a light meson. A single isolated scalar resonance near 4000 MeV is\nfound with large couplings to $D\\bar{D}$, $D_s \\bar{D}_s$ and the kinematically\nclosed $D^* \\bar{D}^*$ channel. A single tensor resonance at a similar mass\ncouples strongly to $D\\bar{D}$, $D\\bar{D}^*$ and $D^* \\bar{D}^*$. We compare\nthe extracted resonances to contemporary experimental candidate states,\nprevious lattice results and theoretical modeling. In contrast to several other\nstudies, we do not find any significant feature in the scalar amplitudes\nbetween the ground state $\\chi_{c0}(1P)$ and the resonance found around 4000\nMeV.",
        "positive": "Quasi-Monte Carlo methods for lattice systems: a first look: We investigate the applicability of Quasi-Monte Carlo methods to Euclidean\nlattice systems for quantum mechanics in order to improve the asymptotic error\nbehavior of observables for such theories. In most cases the error of an\nobservable calculated by averaging over random observations generated from an\nordinary Markov chain Monte Carlo simulation behaves like N^{-1/2}, where N is\nthe number of observations. By means of Quasi-Monte Carlo methods it is\npossible to improve this behavior for certain problems to N^{-1}, or even\nfurther if the problems are regular enough. We adapted and applied this\napproach to simple systems like the quantum harmonic and anharmonic oscillator\nand verified an improved error scaling."
    },
    {
        "anchor": "Deflation of Eigenvalues for GMRES in Lattice QCD: Versions of GMRES with deflation of eigenvalues are applied to lattice QCD\nproblems. Approximate eigenvectors corresponding to the smallest eigenvalues\nare generated at the same time that linear equations are solved. The\neigenvectors improve convergence for the linear equations, and they help solve\nother right-hand sides.",
        "positive": "How much are 2d Yukawa models similar to the Gross-Neveu models?: We present numerical evidence that the 2d Yukawa models with strong quartic\nselfcoupling of the scalar field have the same phase structure and are\nasymptotically free in the Yukawa coupling like the Gross-Neveu models."
    },
    {
        "anchor": "Nuclear force in Lattice QCD: We perform the quenched lattice QCD analysis on the nuclear force\n(baryon-baryon interactions). We employ $20^3\\times 24$ lattice at $\\beta=5.7$\n($a\\simeq 0.19$ fm) with the standard gauge action and the Wilson quark action\nwith the hopping parameters $\\kappa=0.1600, 0.1625, 0.1650$, and generate about\n200 gauge configurations. We measure the temporal correlators of the two-baryon\nsystem which consists of heavy-light-light quarks. We extract the inter-baryon\nforce as a function of the relative distance $r$. We also evaluate the\ncontribution to the nuclear force from each ``Feynman diagram'' such as the\nquark-exchange diagram individually, and single out the roles of Pauli-blocking\neffects or quark exchanges in the inter-baryon interactions.",
        "positive": "Pion in a uniform background magnetic field with clover fermions: Background field methods provide an important nonperturbative formalism for\nthe determination of hadronic properties which are complementary to\nmatrix-element calculations. However, new challenges are encountered when\nutilising a fermion action exposed to additive mass renormalisations. In this\ncase, the background field can induce an undesired field-dependent additive\nmass renormalisation that acts to change the quark mass as the background field\nis changed. For example, in a calculation utilising Wilson fermions in a\nuniform background magnetic field, the Wilson term introduced a field-dependent\nrenormalisation to the quark mass which manifests itself in an unphysical\nincrease of the neutral-pion mass for large magnetic fields. Herein, the clover\nfermion action is studied to determine the extent to which the removal of\n$\\mathcal{O}(a)$ discretisation errors suppresses the field-dependent changes\nto the quark mass. We illustrate how a careful treatment of nonperturbative\nimprovement is necessary to resolve this artefact of the Wilson term. Using the\n$32^3 \\times 64$ dynamical-fermion lattices provided by the PACS-CS\nCollaboration we demonstrate how our technique suppresses the unphysical mass\nrenormalisation over a broad range of magnetic field strengths."
    },
    {
        "anchor": "Non-perturbative renormalization in kaon decays: We discuss the application of the MPSTV non-perturbative method \\cite{NPM} to\nthe operators relevant to kaon decays. This enables us to reappraise the\nlong-standing question of the $\\Delta I=1/2$ rule, which involves\npower-divergent subtractions that cannot be evaluated in perturbation theory.\nWe also study the mixing with dimension-six operators and discuss its\nimplications to the chiral behaviour of the $B_K$ parameter.",
        "positive": "Higgs compositeness in Sp(2N) gauge theories - Determining the\n  low-energy constants with lattice calculations: As a first step towards a quantitative understanding of the SU(4)/Sp(4)\ncomposite Higgs model through lattice calculations, we discuss the low energy\neffective field theory resulting from the SU(4) $\\to$ Sp(4) global symmetry\nbreaking pattern. We then consider an Sp(4) gauge theory with two Dirac fermion\nflavours in the fundamental representation on a lattice, which provides a\nconcrete example of the microscopic realisation of the SU(4)/Sp(4) composite\nHiggs model. For this system, we outline a programme of numerical simulations\naiming at the determination of the low-energy constants of the effective field\ntheory and we test the method on the quenched theory. We also report early\nresults from dynamical simulations, focussing on the phase structure of the\nlattice theory and a calculation of the lowest-lying meson spectrum at coarse\nlattice spacing."
    },
    {
        "anchor": "Investigations of hadron structure on the lattice: Lattice simulations of hadronic structure are now reaching a level where they\nare able to not only complement, but also provide guidance to current and\nforthcoming experimental programmes at, e.g. Jefferson Lab, COMPASS/CERN and\nFAIR/GSI. In this talk I review the progress that has been made in this\nexciting area in the past year and discuss the advances that we can expect to\nsee in the coming year.Topics to be covered include form factors (including\ntransition form factors), moments of ordinary parton and generalised parton\ndistribution functions, moments of distribution amplitudes, and magnetic and\nelectric polarisabilities. I will also highlight the progress being made in\ndetermining disconnected contributions to hadronic properties. Of particular\ninterest here is the size of the contribution to various nucleonic properties\ncoming from strange quarks.",
        "positive": "Toward a Ginsparg-Wilson Lattice Hamiltonian: To address quantum computation of quantities in quantum chromodynamics (QCD)\nfor which chiral symmetry is important, it would be useful to have the\nHamiltonian for a fermion satisfying the Ginsparg-Wilson (GW) equation. I work\nwith an approximate solution to the GW equation which is fractional linear in\ntime derivatives. The resulting Hamiltonian is non-local and has ghosts, but is\nfree of doublers and has the correct continuum limit. This construction works\nin general odd spatial dimensions, and I provide an explicit expression for the\nHamiltonian in 1 spatial dimension."
    },
    {
        "anchor": "A Comparative Study of Some Pseudorandom Number Generators: We present results of an extensive test program of a group of pseudorandom\nnumber generators which are commonly used in the applications of physics, in\nparticular in Monte Carlo simulations. The generators include public domain\nprograms, manufacturer installed routines and a random number sequence produced\nfrom physical noise. We start by traditional statistical tests, followed by\ndetailed bit level and visual tests. The computational speed of various\nalgorithms is also scrutinized. Our results allow direct comparisons between\nthe properties of different generators, as well as an assessment of the\nefficiency of the various test methods. This information provides the best\navailable criterion to choose the best possible generator for a given problem.\nHowever, in light of recent problems reported with some of these generators, we\nalso discuss the importance of developing more refined physical tests to find\npossible correlations not revealed by the present test methods.",
        "positive": "A Lattice Study of Spin and Flavour Symmetry in Heavy Quark Physics: We present a first test of heavy quark spin-flavour symmetries in matrix\nelements for semi-leptonic decays \\bar B to D l\\bar\\nu and \\bar B to D^*\nl\\bar\\nu. We show that O(1/m_Q) corrections are small at masses around the\ncharm for form factors protected by Luke's Theorem, but are of order 30-40 \\%\nfor h_V and h_V/h_{A_{1}}."
    },
    {
        "anchor": "On the strength of the $U_A(1)$ anomaly at the chiral phase transition\n  in $N_f=2$ QCD: We study the thermal transition of QCD with two degenerate light flavours by\nlattice simulations using $O(a)$-improved Wilson quarks. Temperature scans are\nperformed at a fixed value of $N_t = (aT)^{-1}=16$, where $a$ is the lattice\nspacing and $T$ the temperature, at three fixed zero-temperature pion masses\nbetween 200 MeV and 540 MeV. In this range we find that the transition is\nconsistent with a broad crossover. As a probe of the restoration of chiral\nsymmetry, we study the static screening spectrum. We observe a degeneracy\nbetween the transverse isovector vector and axial-vector channels starting from\nthe transition temperature. Particularly striking is the strong reduction of\nthe splitting between isovector scalar and pseudoscalar screening masses around\nthe chiral phase transition by at least a factor of three compared to its value\nat zero temperature. In fact, the splitting is consistent with zero within our\nuncertainties. This disfavours a chiral phase transition in the $O(4)$\nuniversality class.",
        "positive": "An Exact Algorithm for Any-flavor Lattice QCD with Kogut-Susskind\n  Fermion: We propose an exact simulation algorithm for lattice QCD with dynamical\nKogut-Susskind fermion in which the N_f-flavor fermion operator is defined as\nthe N_f/4-th root of the Kogut-Susskind (KS) fermion operator. The algorithm is\nan extension of the Polynomial Hybrid Monte Carlo (PHMC) algorithm to KS\nfermions. The fractional power of the KS fermion operator is approximated with\na Hermitian Chebyshev polynomial, with which we can construct an algorithm for\nany number of flavors. The error which arises from the approximation is\ncorrected by the Kennedy-Kuti noisy Metropolis test. Numerical simulations are\nperformed for the two-flavor case for several lattice parameters in order to\nconfirm the validity and the practical feasibility of the algorithm. In\nparticular tests on a 16^4 lattice with a quark mass corresponding to\nm_{PS}/m_V ~ 0.68 are successfully accomplished. We conclude that our algorithm\nprovides an attractive exact method for dynamical QCD simulations with KS\nfermions."
    },
    {
        "anchor": "Landau gauge gluon and ghost propagators at finite temperature from\n  quenched lattice QCD: The behavior of the Landau gauge gluon and ghost propagators is studied in\npure SU(3) gauge theory at non-zero temperature on the lattice. We concentrate\non the momentum range [0.6, 2.0] GeV. For the longitudinal as well as for the\ntransverse component of the gluon propagator we extract the continuum limit. We\ndemonstrate the smallness of finite-size and Gribov-copy effects at\ntemperatures close to the deconfinement phase transition at T=T_c and within\nthe restricted range of momenta. Since the longitudinal component D_L(q) turns\nout to be most sensitive with respect to the phase transition we propose some\ncombinations of D_L(q) signalling the transition much like \"order parameters\".",
        "positive": "Strange Electric Form Factor of the Proton: By combining the constraints of charge symmetry with new chiral extrapolation\ntechniques and recent low-mass quenched lattice QCD simulations of the\nindividual quark contributions to the electric charge radii of the baryon\noctet, we obtain an accurate determination of the strange electric charge\nradius of the proton. While this analysis provides a value for G_E^s(Q^2=0.1\nGeV^2) in agreement with the best current data, the theoretical error is\ncomparable with that expected from future HAPPEx results from JLab. Together\nwith the earlier determination of G_M^s, this result considerably constrains\nthe role of hidden flavor in the structure of the nucleon."
    },
    {
        "anchor": "New solutions to the Ginsparg-Wilson equation: The overlap operator is just the simplest of a class of Dirac operators with\nan exact chiral symmetry. I demonstrate how a general class of chiral Dirac\noperators can be constructed, show that they have no fermion doublers and that\nthey are all exponentially local, and test my conclusions numerically for a few\nexamples. However, since these operators are more expensive than the overlap\noperator, it is unlikely that they will be useful in practical simulations.",
        "positive": "Fermions in Models with Wilson--Yukawa Couplings: Our work on models with Wilson--Yukawa couplings is reviewed. Conclusions\ninclude the failure of such models to produce continuum chiral gauge theories."
    },
    {
        "anchor": "SO(3) monopoles, vortices and confinement in SU(2) gauge theory: We report on further progress in our programme of understanding confinement\nin 3d and 4d SU(2) gauge theory in terms of Z(2) monopoles. A sufficient\ncondition for confinement was previously translated into Z(2) monopole\ncorrelation inequalities in a related SO(3) gauge theory. We shall discuss the\nphysical picture underlying this scenario and present some Monte Carlo evidence\nconcerning the monopole correlation inequalities.",
        "positive": "Reentrant Behavior in the Domany-Kinzel Cellular Automaton: We present numerical and analytical results for a special kind of\none-dimensional probabilistic cellular automaton, the so called Domany-Kinzel\nautomaton. It is shown that the phase boundary separating the active and the\nrecently found chaotic phase exhibits reentrant behavior. Furthermore exact\nresults for the $p_2$=0-line are discussed."
    },
    {
        "anchor": "Metropolis updates for Diagrammatic Monte-Carlo algorithms from\n  Schwinger-Dyson equations: We describe a general recipe for constructing Metropolis updates for\nDiagrammatic Monte-Carlo (DiagMC) algorithms, based on the Schwinger-Dyson\nequations in quantum field theory. This approach bypasses explicit duality\ntransformations, enumeration or classification of diagrams and can be used for\nlattice quantum field theories with unknown or complicated dual representations\n(such as non-Abelian lattice gauge theories). DiagMC algorithms constructed in\nthis way can still be plagued by the sign problem, which is, however,\ncompletely different from the sign problem in conventional Monte-Carlo\nsimulations and has its origin in cancellations between diagrams with positive\nand negative weights. To test the presented approach, we apply DiagMC to\ncalculate the first 7 orders of 1/N expansion in the quartic matrix model and\nfind good agreement with analytic results, with the exception of the close\nvicinity of the critical coupling where the critical slowing down sets in.",
        "positive": "Renormalons on the Lattice: We present the first lattice calculation of the B-meson binding energy\n$\\labar$ and of the kinetic energy $\\lambda_1/2 m_Q$ of the heavy-quark inside\nthe pseudoscalar B-meson. In order to cancel the ambiguities due to the\nultraviolet renormalons present in the operator matrix elements, this\ncalculation has required the non-perturbative subtraction of the power\ndivergences present in the Lagrangian operator $\\energy$ and in the kinetic\nenergy operator $\\kkinetic$. The non-perturbative renormalization of the\nrelevant operators has been implemented by imposing suitable renormalization\nconditions on quark matrix elements in the Landau gauge."
    },
    {
        "anchor": "Vector meson masses in 2+1 flavor Wilson Chiral Perturbation Theory: We calculate the vector meson masses in $N_{\\rm f} = 2+1$ Wilson chiral\nperturbation theory at next-to-leading order. Generalizing the framework of\nheavy vector meson chiral perturbation theory, the quark mass and the lattice\ncutoff dependence of the vector meson masses is derived. Our chiral order\ncounting assumes that the lattice cut-off artifacts are of the order of the\ntypical pion momenta, $p \\sim a\\Lambda_{\\rm QCD}^{2}$. This counting scheme is\nconsistent with the one in the pseudo scalar meson sector where the O($a^2$)\nterms are included in the leading order chiral Lagrangian.",
        "positive": "Vortex percolation and confinement: The vortex state which arises from a projection of SU(2) to $Z_2$ gauge\ntheory is studied at finite temperatures with a special emphasis on the\ndeconfinement phase transition."
    },
    {
        "anchor": "The Pion Light-Cone Wave Function Phi_pi on the lattice: a partonic\n  signal?: We determine the conditions required to study the pion light-cone wave\nfunction Phi_pi with a new method: a direct display of the partons constituting\nthe pion. We present the preliminary results of a lattice computation of Phi_pi\nfollowing this direction. An auxiliary scalar-quark is introduced. The\nspectroscopy of its bound states is studied. We observe some indications of a\npartonic behavior of the system of this scalar-quark and the anti-quark.",
        "positive": "Heavy quark free energies and screening at finite temperature and\n  density: We study the free energies of heavy quarks calculated from Polyakov loop\ncorrelation functions in full 2-flavour QCD using the p4-improved staggered\nfermion action. A small but finite Baryon number density is included via Taylor\nexpansion of the fermion determinant in the Baryo-chemical potential mu. For\ntemperatures above Tc we extract Debye screening masses from the large distance\nbehaviour of the free energies and compare their mu-dependence to perturbative\nresults."
    },
    {
        "anchor": "Interface Tensions and Perfect Wetting in the Two-Dimensional\n  Seven-State Potts Model: We present a numerical determination of the order-disorder interface tension,\n\\sod, for the two-dimensional seven-state Potts model. We find\n$\\sod=0.0114\\pm0.0012$, in good agreement with expectations based on the\nconjecture of perfect wetting. We take into account systematic effects on the\ntechnique of our choice: the histogram method. Our measurements are performed\non rectangular lattices, so that the histograms contain identifiable plateaus.\nThe lattice sizes are chosen to be large compared to the physical correlation\nlength. Capillary wave corrections are applied to our measurements on finite\nsystems.",
        "positive": "Accelerated Overlap Fermions: Numerical evaluation of the overlap Dirac operator is difficult since it\ncontains the sign function $\\epsilon(H_w)$ of the Hermitian Wilson-Dirac\noperator $H_w$ with a negative mass term. The problems are due to $H_w$ having\nvery small eigenvalues on the equilibrium background configurations generated\nin current day Monte Carlo simulations. Since these are a consequence of the\nlattice discretisation and do not occur in the continuum version of the\noperator, we investigate in this paper to what extent the numerical evaluation\nof the overlap can be accelerated by making the Wilson-Dirac operator more\ncontinuum-like. Specifically, we study the effect of including the clover term\nin the Wilson-Dirac operator and smearing the link variables in the irrelevant\nterms. In doing so, we have obtained a factor of two speedup by moving from the\n  Wilson action to a FLIC (Fat Link Irrelevant Clover) action as the overlap\nkernel."
    },
    {
        "anchor": "Lattice gauge theory without link variables: We obtain a sequence of alternative representations for the partition\nfunction of pure SU(N) or U(N) lattice gauge theory with the Wilson plaquette\naction, using the method of Hubbard-Stratonovich transformations. In\nparticular, we are able to integrate out all the link variables exactly, and\nrecast the partition function of lattice gauge theory as a Gaussian integral\nover auxiliary fields.",
        "positive": "An analysis of 4-quark energies in SU(2) lattice Monte Carlo: Energies of four-quark systems with the tetrahedral geometry measured by the\nstatic quenched SU(2) lattice Monte Carlo method are analyzed by parametrizing\nthe gluon overlap factor in the form exp(-[bs EA+{\\sqrt bs}FP]) where A and P\nare the area and the perimeter defined mainly by the positions of the four\nquarks, bs is the string constant in the 2-quark potentials and E, F are\nconstants."
    },
    {
        "anchor": "Calm Multi-Baryon Operators: Outstanding problems in nuclear physics require input and guidance from\nlattice QCD calculations of few baryons systems. However, these calculations\nsuffer from an exponentially bad signal-to-noise problem which has prevented a\ncontrolled extrapolation to the physical point. The variational method has been\napplied very successfully to two-meson systems, allowing for the extraction of\nthe two-meson states very early in Euclidean time through the use of improved\nsingle hadron operators. The sheer numerical cost of using the same techniques\nin two-baryon systems has been prohibitive. We present an alternate strategy\nwhich offers some of the same advantages as the variational method while being\nsignificantly less numerically expensive. We first use the Matrix Prony method\nto form an optimal linear combination of single baryon interpolating fields\ngenerated from the same source and different sink interpolators. Very early in\nEuclidean time this linear combination is numerically free of excited state\ncontamination, so we coin it a calm baryon. This calm baryon operator is then\nused in the construction of the two-baryon correlation functions.\n  To test this method, we perform calculations on the WM/JLab iso-clover gauge\nconfigurations at the SU(3) flavor symmetric point with m{\\pi} $\\sim$ 800 MeV\n--- the same configurations we have previously used for the calculation of\ntwo-nucleon correlation functions. We observe the calm baryon removes the\nexcited state contamination from the two-nucleon correlation function to as\nearly a time as the single-nucleon is improved, provided non-local (displaced\nnucleon) sources are used. For the local two-nucleon correlation function\n(where both nucleons are created from the same space-time location) there is\nstill improvement, but there is significant excited state contamination in the\nregion the single calm baryon displays no excited state contamination.",
        "positive": "Hot electroweak matter: This talk summarises recent results on lattice Monte Carlo studies of finite\nT electroweak phase transition. Particular attention is given to the 3d\neffective theory approach, replacing the full 4d theory by a three dimensional\neffective theory of the modes constant in imaginary time."
    },
    {
        "anchor": "The string tension for Large N gauge theory from smeared Wilson loops: Using smeared Creutz ratios we extract the string tension for SU(N) pure\ngauge theory and $N$=3,4,5,6,8. We employ these results to extrapolate to large\nN. The same methodology is applied to the single-site Twisted Eguchi Kawai\nmodel. The corresponding string tension matches perfectly within errors with\nthe extrapolated one, providing strong evidence in favour of the twisted\nreduction framework. Interesting results are also obtained on the behaviour of\nCreutz ratios for large sizes.",
        "positive": "General quantum algorithms for Hamiltonian simulation with applications\n  to a non-Abelian lattice gauge theory: With a focus on universal quantum computing for quantum simulation, and\nthrough the example of lattice gauge theories, we introduce rather general\nquantum algorithms that can efficiently simulate certain classes of\ninteractions consisting of correlated changes in multiple (bosonic and\nfermionic) quantum numbers with non-trivial functional coefficients. In\nparticular, we analyze diagonalization of Hamiltonian terms using a\nsingular-value decomposition technique, and discuss how the achieved diagonal\nunitaries in the digitized time-evolution operator can be implemented. The\nlattice gauge theory studied is the SU(2) gauge theory in 1+1 dimensions\ncoupled to one flavor of staggered fermions, for which a complete\nquantum-resource analysis within different computational models is presented.\nThe algorithms are shown to be applicable to higher-dimensional theories as\nwell as to other Abelian and non-Abelian gauge theories. The example chosen\nfurther demonstrates the importance of adopting efficient theoretical\nformulations: it is shown that an explicitly gauge-invariant formulation using\nloop, string, and hadron degrees of freedom simplifies the algorithms and\nlowers the cost compared with the standard formulations based on\nangular-momentum as well as the Schwinger-boson degrees of freedom. The\nloop-string-hadron formulation further retains the non-Abelian gauge symmetry\ndespite the inexactness of the digitized simulation, without the need for\ncostly controlled operations. Such theoretical and algorithmic considerations\nare likely to be essential in quantumly simulating other complex theories of\nrelevance to nature."
    },
    {
        "anchor": "Simulations at fixed topology: fixed topology versus ordinary finite\n  volume corrections: Lattice QCD simulations tend to get stuck in a single topological sector at\nfine lattice spacing, or when using chirally symmetric quarks. In such cases\ncomputed observables differ from their full QCD counterparts by finite volume\ncorrections, which need to be understood on a quantitative level. We extend a\nknown relation from the literature between hadron masses at fixed and at\nunfixed topology by incorporating in addition to topological finite volume\neffects, also ordinary finite volume effects. We present numerical results for\nSU(2) Yang-Mills theory.",
        "positive": "Determination of the Wilson ChPT low energy constant c_2: Following a suggestion by Aoki and B\\\"ar, c2 can be extracted by analyzing\nvolume effects in 2-pion states. To this end we consider renormalized ratios of\nfour point to two point correlation functions. We present the results from\nvarious CLS lattices, with pion masses ranging from 280 to 450 MeV and lattice\nspacings of 0.07 fm and 0.08 fm. This low energy constant is useful to\nunderstand discretization effects in chiral extrapolations with Wilson\nfermions, especially for quantities which vanish in the chiral limit, like the\npion mass. Since our procedure is computationally cheap and straightforward, it\nis recommended as a routine study for any Wilson-type simulation, as a check of\ndiscretization effects."
    },
    {
        "anchor": "Decimation map in 2D for accelerating HMC: To accelerate the HMC with field transformation, we consider a variant of the\ntrivializing map, the decimation map, which can be regarded as a\ncoarse-graining transformation. Using the 2D $U(1)$ pure gauge model, combined\nwith the guided Monte Carlo algorithm, we show that the integrated\nautocorrelation time of the topological charge can be exponentially improved in\nthe wall clock time. Our study indicates that incorporating renormalization\ngroup picture is a powerful and essential ingredient to accelerate the HMC at\nlarge $\\beta$.",
        "positive": "Towards Multigrid Methods for Propagators of Staggered Fermions with\n  Improved Averaging and Interpolation Operators: A Dirac choice for the averaging kernel $C$ is implemented numerically. This\nimproved kernel will be needed in gauge covariant multigrid computations for\npropagators of staggered fermions. Results for $C$ and the variational coarse\ngrid operator will be given in 2-$d$ $SU(2)$ gauge fields. C++ is advocated for\nfuture algorithm development."
    },
    {
        "anchor": "The Charge and Matter radial distributions of Heavy-Light mesons\n  calculated on a lattice: For a heavy-light meson with a static heavy quark, we can explore the light\nquark distribution. The charge and matter radial distributions of these\nheavy-light mesons are measured on a 16^3 * 24 lattice at beta=5.7 and a\nhopping parameter corresponding to a light quark mass about that of the strange\nquark. Both distributions can be well fitted up to 4 lattice spacings (r approx\n0.7 fm) with the exponential form w_i^2(r), where w_i(r)=A exp(-r/r_i). For the\ncharge(c) and matter(m) distributions r_c approx 0.32(2) fm and r_m approx\n0.24(2) fm. We also discuss the normalisation of the total charge and matter\nintegrated over all space, finding 1.30(5) and 0.4(1) respectively.",
        "positive": "The isospin breaking effect on baryons with Nf=2 domain wall fermions: We study the isospin breaking effect on octet baryons. Using the two-flavor\ndynamical domain-wall QCD configurations combined with the quenched non-compact\nQED configurations, the electromagnetic mass splittings between isomultiplets\n(p, n), (Sigma^+, Sigma^0, Sigma^-), (Xi^0, Xi^-) are investigated. We evaluate\nthe main source of statistical fluctuations in the two-point correlation\nfunction, and find that the elimination of O(e) fluctuation (e: the QED charge)\nis essential to extract the signal. Preliminary results for $m_p - m_n$ as well\nas other mass splittings are presented. Possible origin of systematic\nuncertainty is also discussed."
    },
    {
        "anchor": "The Width of the Colour Flux Tube: We discuss and rederive in a general way the logarithmic growth of the mean\nsquared width of the colour flux tube as a function of the interquark\nseparation. Recent data on 3D $Z_2$ gauge theory, combined with high precision\ndata on the interface physics of the 3D Ising model fit nicely this behaviour\nover a range of more than two orders of magnitude.",
        "positive": "Phase diagram evolution at finite coupling in strong coupling lattice\n  QCD: We investigate the chiral phase transition in the strong coupling lattice QCD\nat finite temperature and density with finite coupling effects. We adopt one\nspecies of staggered fermion, and develop an analytic formulation based on\nstrong coupling and cluster expansions. We derive the effective potential as a\nfunction of two order parameters, the chiral condensate sigma and the quark\nnumber density $\\rho_q$, in a self-consistent treatment of the next-to-leading\norder (NLO) effective action terms. NLO contributions lead to modifications of\nquark mass, chemical potential and the quark wave function renormalization\nfactor. While the ratio mu_c(T=0)/Tc(mu=0) is too small in the strong coupling\nlimit, it is found to increase as beta=2Nc/g^2 increases. The critical point is\nfound to move in the lower T direction as beta increases. Since the vector\ninteraction induced by $\\rho_q$ is shown to grow as beta, the present trend is\nconsistent with the results in Nambu-Jona-Lasinio models. The interplay between\ntwo order parameters leads to the existence of partially chiral restored\nmatter, where effective chemical potential is automatically adjusted to the\nquark excitation energy."
    },
    {
        "anchor": "Overlap Hypercube Fermions in QCD Simulations Near the Chiral Limit: The overlap hypercube fermion is a variant of a chirally symmetric lattice\nfermion, which is endowed with a higher level of locality than the standard\noverlap fermion. We apply this formulation in quenched QCD simulations with\nlight quarks. In the p-regime we evaluate the masses of light pseudoscalar and\nvector mesons, as well as the pion decay constant and the renormalisation\nconstant Z_A. In the epsilon-regime we present results for the leading Low\nEnergy Constants of the chiral Lagrangian, Sigma and F_pi. To this end, we\nperform fits to predictions by chiral Random Matrix Theory and by different\nversions of quenched Chiral Perturbation Theory, referring to distinct\ncorrelation functions. These results, along with an evaluation of the\ntopological susceptibility, are also compared to the outcome based on the\nstandard overlap operator.",
        "positive": "Non-perturbative running of renormalization constants from correlators\n  in coordinate space using step scaling: Working in a quenched setup with Wilson twisted mass valence fermions, we\nexplore the possibility to compute non-perturbatively the step scaling function\nusing the coordinate (X-space) renormalization scheme. This scheme has the\nadvantage of being on-shell and gauge invariant. The step scaling method allows\nus to calculate the running of the renormalization constants of quark bilinear\noperators. We describe here the details of this calculation. The aim of this\nexploratory study is to identify the feasibility of the X-space scheme when\nused in small volume simulations required by the step scaling technique.\nEventually, we translate our final results to the continuum MSbar scheme and\ncompare against four-loop analytic formulae finding satisfactory agreement."
    },
    {
        "anchor": "Lattice Monte-Carlo study of pre-conformal dynamics in strongly\n  flavoured QCD in the light of the chiral phase transition at finite\n  temperature: We study the thermal phase transition in colour SU(3) Quantum Chromodynamics\n(QCD) with a variable number of fermions in the fundamental representation by\nusing lattice Monte-Carlo simulations. We collect the (pseudo) critical\ncouplings for N_f=(0, 4, 6,8), and we investigate the pre-conformal dynamics\nassociated with the infra-red fixed point in terms of the N_f dependence of the\ntransition temperature. We propose three independent estimates of the number of\nflavour N_f^* where the conformal phase would emerge, which give consistent\nresults within the largish errors. We consider lines of fixed N_t in the space\nof (N_f, bare lattice coupling), and locate the vanishing of the step scaling\nfunction for N_f^*\\sim 11.1\\pm 1.6. We define a typical interaction strength\n(g_TC) at the scale of critical temperature T_c, and we find that g_TC meets\nthe zero temperature critical couplings estimated by the two-loop Schwinger\nDyson equation or the IRFP coupling in the four-loop beta-function at N_f^*\\sim\n12.5\\pm 0.7. Further, we study the N_f dependences of T_c/M where M is a UV N_f\nindependent reference scale determined by utilising the coupling at the scale\nof the lattice spacing. Then, T_c/M turns out to be a decreasing function of\nN_f, and the vanishing T_c/M indicates the emergence of the conformal window at\nN_f^* \\sim 10.4 \\pm 1.2.",
        "positive": "How to Put a Heavier Higgs on the Lattice: Lattice work, exploring the Higgs mass triviality bound, seems to indicate\nthat a strongly interacting scalar sector in the minimal standard model cannot\nexist while low energy QCD phenomenology seems to indicate that it could. We\nattack this puzzle using the 1/N expansion and discover a simple criterion for\nselecting a lattice action that is more likely to produce a heavy Higgs\nparticle. Our large $N$ calculation suggests that the Higgs mass bound might be\naround $850 GeV$, which is about 30% higher than previously obtained."
    },
    {
        "anchor": "Disconnected contributions to hadronic structure: a new method for\n  stochastic noise reduction: We present a new method for reducing the stochastic noise of all-to-all\npropagators based on stopping the inversion of the propagator before\nconvergence. The method is easy to implement, unbiased and independent of the\nquark action. Applying this method to the calculation of disconnected loops\nneeded for hadronic structure observables we find savings in computer time of\nfactors of 4-12 depending on the operator inserted in the loop. When combined\nwith a hopping parameter expansion technique we obtain combined gains of up to\nfactors of 30 for some operators.",
        "positive": "Topics in Lattice QCD and Effective Field Theory: Effective field theories provide a formalism for categorizing low-energy\neffects of a high-energy fundamental theory in terms of the low-energy degrees\nof freedom. This process has been well established in mapping the fundamental\ntheory of QCD in terms of the hadronic degrees of freedom, which allows for\nquantitative connections and predictions between hardronic observables. A more\ndirect approach to performing the non-perturbative QCD calculations is through\nlattice QCD. These computationally intensive calculations approximate continuum\nphysics with a discretized lattice to extract hadronic phenomena from first\nprinciples. However, as in any approximation, there are multiple systematic\nerrors between lattice QCD calculation and actual hardronic phenomena. To\naccount for these systematic effects in terms of hadronic interactions,\neffective field theory proves to be useful. However, the fundamental theory of\ninterest here is lattice QCD, as opposed to the usual continuum QCD. In this\nwork, the basics of this process are outlined, and multiple original\ncalculations are presented: effective field theory for anisotropic lattices,\nI=2 $\\pi\\pi$ scattering for isotropic, anisotropic, and twisted mass lattices.\nAdditionally, a usage of effective field theories and the employment of an\nisospin chemical potential on the lattice is proposed to extract several\ncomputationally difficult scattering parameters. Lastly, recently proposed\nlocal, chiral lattice actions are analyzed in the framework of effective field\ntheory, which illuminates various challenges in simulating such actions."
    },
    {
        "anchor": "A study of quark-gluon vertices using the lattice Coulomb gauge domain\n  wall fermion: I calculate the quark-gluon vertex of the tensor type\n$\\Gamma(p,q)=g_3(p,q)p_4 \\Slash{\\Vec q}$, vector type $g_2(p,q)\\Vec q$ and\nscalar type $g_1(p,q)$, for a small spacial momentum transfer $q=\\bf q$ using\nthe gauge configuration of the Domain Wall Fermion (DWF) provided by the\nRBC-UKQCD collaboration.\n  The quark propagator of Coulomb gauge in the cylinder cut, i.e. the four\nmomentum $p$ is directed along the diagonal of the hyper-cubic space has small\nfluctuation and I use this propagator in the evaluation of the operators by\napplying the non-perturbative renormalization method.\n  The $q$ dependence of the running coupling $\\alpha_{s,g_1}(q)$ is compared\nwith $\\alpha_I(q)$ measured by the ghost-gluon vertex in Coulomb gauge and\n$\\alpha_s(q)$ measured in Landau gauge.",
        "positive": "UV Suppression by Smearing and Screening Correlators: We investigate the mechanism of smearing in the APE, Stout, HYP and HEX\nschemes through their effect on glue and quark Fourier modes. Using this, we\nnon-perturbatively tune the smearing parameters to their optimum values.\nSmearing causes a super-linear improvement in taste symmetry breaking in the\nhigh temperature phase of QCD. We use optimal smearing in the high temperature\nphase and find close agreement of meson screening masses with weak coupling\npredictions."
    },
    {
        "anchor": "Lattice investigation of the general Two Higgs Doublet Model with\n  $SU(2)$ gauge fields: We study the most general Two Higgs Doublet Model with $SU(2)$ gauge fields\non the lattice. The phase space is probed through the computation of\ngauge-invariant global observables serving as proxies for order parameters. In\neach phase, the spectrum of the theory is analysed for different combinations\nof bare couplings and different symmetry breaking patterns. The scale setting\nand determination of the running gauge coupling are performed through the\nWilson flow computation of the action density.",
        "positive": "Weak decay constants of the neutral pseudoscalar mesons from lattice\n  QCD+QED: With increasing requirements for greater precision, it becomes essential to\ndescribe the effects of isospin breaking induced by both quark masses and\nelectro-magnetic effects. In this work we perform a lattice analysis of the\nweak decay constants of the neutral pseudoscalar mesons including such isospin\nbreaking effects, with particular consideration being given to the state mixing\nof the $\\pi^0$, $\\eta$ and $\\eta^\\prime$. We also detail extensions to the\nnon-perturbative RI$^\\prime$-MOM renormalization scheme for application to\nnon-degenerate flavour-neutral operators which are permitted to mix, and\npresent initial results. Using flavour-breaking expansions in terms of quark\nmasses and charges we determine the leptonic decay constants for the $\\pi^0$\nand $\\eta$ mesons, demonstrating in principle how precision determinations of\nall neutral pseudoscalar decay constants could be reached in lattice QCD with\nQED and strong isospin-breaking accounted for."
    },
    {
        "anchor": "Nucleon electromagnetic form factors with Wilson fermions: The nucleon electromagnetic form factors continue to be of major interest for\nexperimentalists and phenomenologists alike. They provide important insights\ninto the structure of nuclear matter. For a range of interesting momenta they\ncan be calculated on the lattice. The limiting factor continues to be the value\nof the pion mass. We present the latest results of the QCDSF collaboration\nusing gauge configurations with two dynamical, non-perturbatively improved\nWilson fermions at pion masses as low as 350 MeV.",
        "positive": "Lattice Calculation of Parton Distribution Function from LaMET at\n  Physical Pion Mass with Large Nucleon Momentum: We present a lattice-QCD calculation of the unpolarized isovector parton\ndistribution function (PDF) using ensembles at the physical pion mass with\nlarge proton boost momenta $P_z \\in \\{2.2,2.6,3.0\\}$~GeV within the framework\nof large-momentum effective theory (LaMET). In contrast to our previous\nphysical-pion PDF result, we increase the statistics significantly, double the\nboost momentum, increase the investment in excited-state contamination\nsystematics, and switch to $\\gamma_t$ operator to avoid mixing with scalar\nmatrix elements. We use four source-sink separations in our analysis to control\nthe systematics associated with excited-state contamination. The one-loop LaMET\nmatching corresponding to the new operator is calculated and applied to our\nlattice data. We detail the systematics that affect PDF calculations, providing\nguidelines to improve the precision of future lattice PDF calculations. We find\nour final parton distribution to be in reasonable agreement with the PDF\nprovided by the latest phenomenological analysis."
    },
    {
        "anchor": "Landau gauge ghost and gluon propagators and the Faddeev-Popov operator\n  spectrum: In this talk we report on a recent lattice investigation of the Landau gauge\ngluon and ghost propagators in pure SU(3) lattice gauge theory with a special\nemphasis on the Gribov copy problem. In the (infrared) region of momenta $q^2\n\\le 0.3 \\mathrm{GeV}^2$ we find the corresponding MOM scheme running coupling\n$\\alpha_s(q^2)$ to rise in $q$. We also report on a first SU(3) computation of\nthe ghost-gluon vertex function showing that it deviates only weakly from being\nconstant. In addition we study the spectrum of low-lying eigenvalues and\neigenfunctions of the Faddeev-Popov operator as well as the spectral\nrepresentation of the ghost propagator.",
        "positive": "Electroweak box diagrams on the lattice for pion and neutron decay: CKM matrix is unitary by construction in the standard model(SM). The recent\nanalyses on the first row of CKM matrix show $ \\approx 3\\sigma$ tension with\nunitarity. Nonperturbative calculations of the radiative corrections can reduce\nthe theory uncertainty in CKM matrix elements. Here we compute the electroweak\nbox contribution to the pion and kaon $\\beta$ decays using seven $N_f=2+1+1$\nHISQ-Clover lattice with various pion mass and lattice spacing. The continuum\nand chiral limit is taken using the leading dependence on $M_\\pi$ and $a$,\nwhere $M_\\pi$ extrapolation is taken to the physical pion mass and $SU(3)$\nsymmetric mass for pion and kaon box contribution, respectively. Our results\nare $ \\square_{\\gamma W}^{VA} |_{\\pi} = 2.820 (28) \\times 10^{-3} $ and $\n\\square_{\\gamma W}^{VA} |_{K} = 2.384 (17) \\times 10^{-3} $."
    },
    {
        "anchor": "Status of and performance estimates for QCDOC: QCDOC is a supercomputer designed for high scalability at a low cost per\nnode. We discuss the status of the project and provide performance estimates\nfor large machines obtained from cycle accurate simulation of the QCDOC ASIC.",
        "positive": "Sampling using $SU(N)$ gauge equivariant flows: We develop a flow-based sampling algorithm for $SU(N)$ lattice gauge theories\nthat is gauge-invariant by construction. Our key contribution is constructing a\nclass of flows on an $SU(N)$ variable (or on a $U(N)$ variable by a simple\nalternative) that respect matrix conjugation symmetry. We apply this technique\nto sample distributions of single $SU(N)$ variables and to construct flow-based\nsamplers for $SU(2)$ and $SU(3)$ lattice gauge theory in two dimensions."
    },
    {
        "anchor": "High-Precision c and b Masses, and QCD Coupling from Current-Current\n  Correlators in Lattice and Continuum QCD: We extend our earlier lattice-QCD analysis of heavy-quark correlators to\nsmaller lattice spacings and larger masses to obtain new values for the c mass\nand QCD coupling, and, for the first time, values for the b mass:\nm_c(3GeV,n_f=4)=0.986(6)GeV, alpha_msb(M_Z,n_f=5)=0.1183(7), and\nm_b(10GeV,n_f=5)=3.617(25)GeV. These are among the most accurate determinations\nby any method. We check our results using a nonperturbative determination of\nthe mass ratio m_b(mu,n_f)/m_c(mu,n_f); the two methods agree to within our 1%\nerrors and taken together imply m_b/m_c=4.51(4). We also update our previous\nanalysis of alpha_msb from Wilson loops to account for revised values for r_1\nand r_1/a, finding a new value alpha_\\msb(M_Z,n_f=5)=0.1184(6); and we update\nour recent values for light-quark masses from the ratio m_c/m_s. Finally, in\nthe Appendix, we derive a procedure for simplifying and accelerating\ncomplicated least-squares fits.",
        "positive": "Two-point functions in 4D dynamical triangulation: In the dynamical triangulation model of 4D euclidean quantum gravity we\nmeasure two-point functions of the scalar curvature as a function of the\ngeodesic distance. To get the correlations it turns out that we need to\nsubtract a squared one-point function which, although this seems paradoxical,\ndepends on the distance. At the transition and in the elongated phase we\nobserve a power law behaviour, while in the crumpled phase we cannot find a\nsimple function to describe it."
    },
    {
        "anchor": "The chiral transition of N_f=2 QCD with fundamental and adjoint fermions: We study QCD with two staggered Dirac fermions both in the fundamental (QCD)\nand the adjoint representation (aQCD) near the chiral transition. The aim is to\nfind the universality class of the chiral transition and to verify Goldstone\neffects below the transition. We investigate aQCD, because in that theory the\ndeconfinement and the chiral transitions occur at different temperatures\nT_d<T_c. Here, we show that the scaling behaviour of the chiral condensate in\nthe vicinity of \\beta_c is in full agreeement with that of the 3d O(2)\nuniversality class. In the region T_d<T<T_c we confirm the quark mass\ndependence of the chiral condensate which is expected due to the existence of\nGoldstone modes like in 3d O(N) spin models. For fundamental QCD we use the\np4-action. Here, we find Goldstone effects below T_c like in aQCD and the 3d\nO(N) spin models, however no O(2)/O(4) scaling near the chiral transition\npoint. The result for QCD may be a consequence of the coincidence of the\ndeconfinement transition with the chiral transition.",
        "positive": "Light pseudoscalar decay constants, quark masses, and low energy\n  constants from three-flavor lattice QCD: As part of our program of lattice simulations of three flavor QCD with\nimproved staggered quarks, we have calculated pseudoscalar meson masses and\ndecay constants for a range of valence quark masses and sea quark masses on\nlattices with lattice spacings of about 0.125 fm and 0.09 fm. We fit the\nlattice data to forms computed with staggered chiral perturbation theory. Our\nresults provide a sensitive test of the lattice simulations, and especially of\nthe chiral behavior, including the effects of chiral logarithms. We find:\nf_\\pi=129.5(0.9)(3.5)MeV, f_K=156.6(1.0)(3.6)MeV, and f_K/f_\\pi=1.210(4)(13),\nwhere the errors are statistical and systematic. Following a recent paper by\nMarciano, our value of f_K/f_\\pi implies |V_{us}|=0.2219(26). Further, we\nobtain m_u/m_d= 0.43(0)(1)(8), where the errors are from statistics, simulation\nsystematics, and electromagnetic effects, respectively. The data can also be\nused to determine several of the constants of the low energy effective\nLagrangian: in particular we find 2L_8-L_5=-0.2(1)(2) 10^{-3} at chiral scale\nm_\\eta. This provides an alternative (though not independent) way of estimating\nm_u; 2L_8-L_5 is far outside the range that would allow m_u=0. Results for\nm_s^\\msbar, \\hat m^\\msbar, and m_s/\\hat m can be obtained from the same lattice\ndata and chiral fits, and have been presented previously in joint work with the\nHPQCD and UKQCD collaborations. Using the perturbative mass renormalization\nreported in that work, we obtain m_u^\\msbar=1.7(0)(1)(2)(2)MeV and\nm_d^\\msbar=3.9(0)(1)(4)(2)MeV at scale 2 GeV, with errors from statistics,\nsimulation, perturbation theory, and electromagnetic effects, respectively."
    },
    {
        "anchor": "Lattice QCD study of inclusive semileptonic decays of heavy mesons: We present an ab initio study of inclusive semileptonic decays of heavy\nmesons from lattice QCD. Our approach is based on a recently proposed method,\nthat allows one to address the study of these decays from the analysis of\nsmeared spectral functions extracted from four-point correlators on the\nlattice, where the smearing is defined in terms of the phase-space integration\nrelevant to the inclusive decays. We present results obtained from gauge-field\nensembles from the JLQCD and ETM collaborations, and discuss their relation\nwith theoretical predictions from the operator-product expansion.",
        "positive": "Chirality on the Lattice: During the last several years a non-perturbative formulation of exact chiral\nsymmetry on the lattice has been developed. I shall outline the main ideas of\nthese developments and discuss prospects for the future. The focus will be on\nthe basic concepts enciphered in a new jargon consisting of terms like\n``infinite number of fermions'', ``domain wall fermions'', ``the overlap'',\n``the Ginsparg-Wilson relation''. Technical details will be omitted."
    },
    {
        "anchor": "On the I=2 channel pi-pi interaction in the chiral limit: An approximate local potential for the residual pi+ pi+ interaction is\ncomputed. We use an O(a**2) improved action on a coarse 9x9x9x13 lattice with\napproximately a=0.4fm. The results present a continuation of previous work:\nIncreasing the number of gauge configurations and quark propagators we attempt\nextrapolation of the pi+ pi+ potential to the chiral limit.",
        "positive": "Quark number susceptibilities at finite chemical potential from fugacity\n  expansion: Generalized quark number susceptibilities are expected to be good probes for\nthe phase transitions in QCD and the search of a possible critical point.\nHowever, their computation in lattice QCD is plagued by the complex action\nproblem which appears at finite chemical potential mu. In this work we explore\nthe possibilities of an expansion in the fugacity parameter exp(mu beta) which\nhas features that make, in particular quark number related bulk observables\neasily accessible. We present results at finite chemical potential for\ngeneralized susceptibilities up to the 4th order as well as their ratios and\ncompare them to model calculations."
    },
    {
        "anchor": "Low-energy Scattering and Effective Interactions of Two Baryons at\n  $m_\u03c0\\sim 450$ MeV from Lattice Quantum Chromodynamics: The interactions between two octet baryons are studied at low energies using\nlattice QCD (LQCD) with larger-than-physical quark masses corresponding to a\npion mass of $m_{\\pi}\\sim 450$ MeV and a kaon mass of $m_{K}\\sim 596$ MeV. The\ntwo-baryon systems that are analyzed range from strangeness $S=0$ to $S=-4$ and\ninclude the spin-singlet and triplet $NN$, $\\Sigma N$ ($I=3/2$), and $\\Xi\\Xi$\nstates, the spin-singlet $\\Sigma\\Sigma$ ($I=2$) and $\\Xi\\Sigma$ ($I=3/2$)\nstates, and the spin-triplet $\\Xi N$ ($I=0$) state. The $s$-wave scattering\nphase shifts, low-energy scattering parameters, and binding energies when\napplicable, are extracted using L\\\"uscher's formalism. While the results are\nconsistent with most of the systems being bound at this pion mass, the\ninteractions in the spin-triplet $\\Sigma N$ and $\\Xi\\Xi$ channels are found to\nbe repulsive and do not support bound states. Using results from previous\nstudies at a larger pion mass, an extrapolation of the binding energies to the\nphysical point is performed and is compared with experimental values and\nphenomenological predictions. The low-energy coefficients in pionless EFT\nrelevant for two-baryon interactions, including those responsible for $SU(3)$\nflavor-symmetry breaking, are constrained. The $SU(3)$ symmetry is observed to\nhold approximately at the chosen values of the quark masses, as well as the\n$SU(6)$ spin-flavor symmetry, predicted at large $N_c$. A remnant of an\naccidental $SU(16)$ symmetry found previously at a larger pion mass is further\nobserved. The $SU(6)$-symmetric EFT constrained by these LQCD calculations is\nused to make predictions for two-baryon systems for which the low-energy\nscattering parameters could not be determined with LQCD directly in this study,\nand to constrain the coefficients of all leading $SU(3)$ flavor-symmetric\ninteractions, demonstrating the predictive power of two-baryon EFTs matched to\nLQCD.",
        "positive": "Composite Reweighting the Glasgow Method for Finite Density QCD: The reweighting method developed in Glasgow to circumvent the lattice action\nbecoming complex at finite density suffers from a pathological onset transition\nthought to be due to the reweighting. We present a new reweighting scheme based\non this approach in which we combine ensembles to alleviate the sampling bias\nwe identify in the polynomial coefficients of the fugacity expansion."
    },
    {
        "anchor": "Chiral phase transition and Anderson localization in the Instanton\n  Liquid Model for QCD: We study the spectrum and eigenmodes of the QCD Dirac operator in a gauge\nbackground given by an Instanton Liquid Model (ILM) at temperatures around the\nchiral phase transition. Generically we find the Dirac eigenvectors become more\nlocalized as the temperature is increased. At the chiral phase transition, both\nthe low lying eigenmodes and the spectrum of the QCD Dirac operator undergo a\ntransition to localization similar to the one observed in a disordered\nconductor. This suggests that Anderson localization is the fundamental\nmechanism driving the chiral phase transition. We also find an additional\ntemperature dependent mobility edge (separating delocalized from localized\neigenstates) in the bulk of the spectrum which moves toward lower eigenvalues\nas the temperature is increased. In both regions, the origin and the bulk, the\ntransition to localization exhibits features of a 3D Anderson transition\nincluding multifractal eigenstates and spectral properties that are well\ndescribed by critical statistics. Similar results are obtained in both the\nquenched and the unquenched case though the critical temperature in the\nunquenched case is lower. Finally we argue that our findings are not in\nprinciple restricted to the ILM approximation and may also be found in lattice\nsimulations.",
        "positive": "Some Interesting Features of Noncompact QED_3: We study the phase diagram of non compact $QED_3$ using the $MFA$ method and\npresent evidence for a continuous phase transition line at small $N_f$. We also\nanalyze the chiral structure of the vacuum by means of the computation of the\nprobability distribution function of the order parameter in the exact chiral\nlimit."
    },
    {
        "anchor": "Pi-K Scattering in Full QCD with Domain-Wall Valence Quarks: We calculate the pi+ K+ scattering length in fully-dynamical lattice QCD with\ndomain-wall valence quarks on MILC lattices with rooted staggered sea-quarks at\na lattice spacing of b=0.125 fm, lattice spatial size of L =2.5 fm and at pion\nmasses of m_pi=290, 350, 490 and 600 MeV. The lattice data, analyzed at\nnext-to-leading order in chiral perturbation theory, allows an extraction of\nthe full pi K scattering amplitude at threshold. Extrapolating to the physical\npoint gives m_pi a_3/2 = -0.0574 (+- 0.0016)(+0.0024 -0.0058) and m_pi a_1/2 =\n0.1725 (+- 0.0017)(+0.0023 -0.0156) for the I=3/2 and I=1/2 scattering lengths,\nrespectively, where the first error is statistical and the second error is an\nestimate of the systematic due to truncation of the chiral expansion.",
        "positive": "Light Spectrum and Decay Constants in Full QCD with Wilson Fermions: We present results from an analysis of the light spectrum and the decay\nconstants f_{\\pi} and f_V^{-1} in Full QCD with n_f=2 Wilson fermions at a\ncoupling of beta=5.6 on a 16^3x32 lattice."
    },
    {
        "anchor": "Lattice analysis for the energy scale of QCD phenomena: We formulate a new framework in lattice QCD to study the relevant energy\nscale of QCD phenomena. By considering the Fourier transformation of link\nvariable, we can investigate the intrinsic energy scale of a physical quantity\nnonperturbatively. This framework is broadly available for all lattice QCD\ncalculations. We apply this framework for the quark-antiquark potential and\nmeson masses in quenched lattice QCD. The gluonic energy scale relevant for the\nconfinement is found to be less than 1 GeV in the Landau or Coulomb gauge.",
        "positive": "The curvature of the critical surface (m_ud,m_s)^{crit}(mu): a progress\n  report: At zero chemical potential mu, the order of the temperature-driven\nquark-hadron transition depends on the quark masses m_{u,d} and m_s. Along a\ncritical line bounding the region of first-order chiral transitions in the\n(m_{u,d},m_s) plane, this transition is second order. When the chemical\npotential is turned on, this critical line spans a surface, whose curvature at\nmu=0 can be determined without any sign or overlap problem. Our past\nmeasurements on N_t=4 lattices suggest that the region of quark masses for\nwhich the transition is first order shrinks when mu is turned on, which makes a\nQCD chiral critical point at small mu/T unlikely. We present results from two\ncomplementary methods, which can be combined to yield information on\nhigher-order terms. It turns out that the O(mu^4) term reinforces the effect of\nthe leading O(mu^2) term, and there is strong evidence that the O(mu^6) and\nO(mu^8) terms do as well. We also report on simulations underway, where the\nstrange quark is given its physical mass, and where the lattice spacing is\nreduced."
    },
    {
        "anchor": "Light Nuclei from Lattice QCD: Spectrum, Structure and Reactions: Lattice Quantum Chromodynamics (LQCD) studies of light nuclei have entered an\nera when first results on structure and reaction properties of light nuclei\nhave emerged in recent years, complementing existing results on their\nlowest-lying spectra. Although in these preliminary studies the quark masses\nare still set to larger than the physical values, a few results at the physical\npoint can still be deduced from simple extrapolations in the quark masses. The\nprogress paves the road towards obtaining several important quantities in\nnuclear physics, such as nuclear forces and nuclear matrix elements relevant\nfor pp fusion, single and double-beta decay processes, neutrino-nucleus\nscattering, searches for CP violation, nuclear response in direct dark-matter\ndetection experiments, as well as gluonic structure of nuclei for an\nElectron-Ion Collider (EIC) program. Some of the recent developments, the\nresults obtained, and the outlook of the field will be briefly reviewed in this\ntalk, with a focus on results obtained by the Nuclear Physics From LQCD\n(NPLQCD) collaboration.",
        "positive": "The equation of state in lattice QCD: with physical quark masses towards\n  the continuum limit: The equation of state of QCD at vanishing chemical potential as a function of\ntemperature is determined for two sets of lattice spacings. Coarser lattices\nwith temporal extension of N_t=4 and finer lattices of N_t=6 are used. Symanzik\nimproved gauge and stout-link improved staggered fermionic actions are applied.\nThe results are given for physical quark masses both for the light quarks and\nfor the strange quark. Pressure, energy density, entropy density, quark number\nsusceptibilities and the speed of sound are presented."
    },
    {
        "anchor": "Topological Susceptibility to High Temperatures via Reweighting: We measure the topological susceptibility of quenched QCD on the lattice at\ntwo high temperatures. For this, we define topology with the help of gradient\nflow and mitigate the statistical problem of topology at high temperatures\nusing a reweighting technique. This allows us to enhance tunneling events\nbetween topological sectors and alleviate topological freezing. We quote\ncontinuum extrapolated results for the susceptibility at $2.5$ and\n$4.1~T_\\mathrm c$ that agree well with the existing literature. We conclude\nthat the method is feasible and can be extended to unquenched QCD with no\nconceptual problems.",
        "positive": "Bayesian priors and nuisance parameters: Bayesian techniques are widely used to obtain spectral functions from\ncorrelators. We suggest a technique to rid the results of nuisance parameters,\nie, parameters which are needed for the regularization but cannot be determined\nfrom data. We give examples where the method works, including a pion mass\nextraction with two flavours of staggered quarks at a lattice spacing of about\n0.07 fm. We also give an example where the method does not work."
    },
    {
        "anchor": "Running Coupling and the Lambda-Parameter from SU(3) Lattice Simulations: We present new results on the static qq-potential from high statistics\nsimulations on 32^4 and smaller lattices, using the standard Wilson beta = 6.0,\n6.4, and 6.8. Within our statistical errors we do not observe any finite size\neffects affecting the potential values, on varying the spatial lattice extent\nfrom 0.9fm up to 3.3fm. We are able to see and quantify the running of the\ncoupling from the Coulomb behaviour of the interquark force. From this we\nextract the ratio \\sqrt{sigma}/Lambda_L. We demonstrate that scaling violations\non the string tension can be considerably reduced by introducing effective\ncoupling schemes, which allow for a safe extrapolation of \\Lambda_L to its\ncontinuum value. Both methods yield consistent values for Lambda: Lambda_MSbar\n= 0.558_{-0.007}^{+0.017}\\sqrt{sigma} = 246_{-3}^{+7}MeV. At the highest energy\nscale attainable to us we find alpha(5 GeV) = 0.150(3)",
        "positive": "Comparing the Nambu-Goto string with LGT results: We discuss a way to evaluate the full prediction for the interquark potential\nwhich is expected from the effective Nambu-Goto string model. We check the\ncorrectness of the prescription reproducing the results obtained with the zeta\nfunction regularization for the first two perturbative orders. We compare the\npredictions with existing Monte Carlo data for the (2+1) dimensional Z(2),\nSU(2) and SU(3) gauge theories: in the low temperature regime, we find good\nagreement for large enough interquark distances, but an increasing mismatch\nbetween theoretical predictions and numerical results is observed as shorter\nand shorter distances are investigated. On the contrary, at high temperatures\n(approaching the deconfinement transition from below) a remarkable agreement\nbetween Monte Carlo data and the expectations from the Nambu-Goto effective\nstring is observed for a wide range of interquark distances."
    },
    {
        "anchor": "The Electroweak Phase Transition: A Non-Perturbative Analysis: We study on the lattice the 3d SU(2)+Higgs model, which is an effective\ntheory of a large class of 4d high temperature gauge theories. Using the exact\nconstant physics curve, continuum ($V\\to\\infty, a\\to 0$) results for the\nproperties of the phase transition (critical temperature, latent heat,\ninterface tension) are given. The 3-loop correction to the effective potential\nof the scalar field is determined. The masses of scalar and vector excitations\nare determined and found to be larger in the symmetric than in the broken\nphase. The vector mass is considerably larger than the scalar one, which\nsuggests a further simplification to a scalar effective theory at large Higgs\nmasses. The use of consistent 1-loop relations between 3d parameters and 4d\nphysics permits one to convert the 3d simulation results to quantitatively\naccurate numbers for different physical theories, such as the Standard Model --\nexcluding possible nonperturbative effects of the U(1) subgroup -- for Higgs\nmasses up to about 70 GeV. The applications of our results to cosmology are\ndiscussed.",
        "positive": "Meron-Cluster Solution of Fermion and Other Sign Problems: Numerical simulations of numerous quantum systems suffer from the notorious\nsign problem. Important examples include QCD and other field theories at\nnon-zero chemical potential, at non-zero vacuum angle, or with an odd number of\nflavors, as well as the Hubbard model for high-temperature superconductivity\nand quantum antiferromagnets in an external magnetic field. In all these cases\nstandard simulation algorithms require an exponentially large statistics in\nlarge space-time volumes and are thus impossible to use in practice.\nMeron-cluster algorithms realize a general strategy to solve severe sign\nproblems but must be constructed for each individual case. They lead to a\ncomplete solution of the sign problem in several of the above cases."
    },
    {
        "anchor": "Higgs mechanism in five-dimensional gauge theories: Lattice simulations of five-dimensional gauge theories on an orbifold\nrevealed that there is spontaneous symmetry breaking. Some of the\nextra-dimensional components of the gauge field play the role of a Higgs field\nand some of the four-dimensional components become massive gauge bosons. The\neffect is confirmed by computing the Coleman-Weinberg potential with a cutoff.\nWe compare the results of this computation with the lattice data.",
        "positive": "Microscopic Origin of Criticality at Macroscale in QCD Chiral Phase\n  Transition: We reveal that the criticality of the chiral phase transition in QCD at the\nmacroscale arises from the microscopic energy levels of its fundamental\nconstituents, the quarks. We establish a novel relation between cumulants of\nthe chiral order parameter (i.e., chiral condensate) and correlations among the\nenergy levels of quarks (i.e., eigenspectra of the massless Dirac operator),\nwhich naturally leads to a generalization of the Banks-Casher relation. Based\non this novel relation and through (2+1)-flavor lattice QCD calculations using\nthe HISQ action with varying light quark masses in the vicinity of the chiral\nphase transition, we demonstrate that the correlations among the infrared part\nof the Dirac eigenspectra exhibit same universal scaling behaviors as expected\nof the cumulants of the chiral condensate. We find that these universal scaling\nbehaviors extend up to the physical values of the up and down quark masses."
    },
    {
        "anchor": "The Phase Structure of the Schwinger Model on the Lattice with Wilson\n  Fermions in the Hartree-Fock Approximation: The phase diagram of the Schwinger model on the lattice with one and two\ndegenerate flavours of Wilson fermions is investigated in the Hartree-Fock\napproximation. In case of a single flavour (not directly amenable to numerical\nsimulation), the calculation indicates the existence of the parity violating\nphase at both weak and intermediate-to-strong couplings. In the broken phase,\nthe Hartree-Fock vacuum sustains a nonzero electric field. With two flavours,\nparity is not broken at weak coupling. However, both parity and flavour become\nspontaneously broken at the Hartree-Fock level as the coupling becomes strong.",
        "positive": "From Doubled Chern-Simons-Maxwell Lattice Gauge Theory to Extensions of\n  the Toric Code: We regularize compact and non-compact Abelian Chern-Simons-Maxwell theories\non a spatial lattice using the Hamiltonian formulation. We consider a doubled\ntheory with gauge fields living on a lattice and its dual lattice. The Hilbert\nspace of the theory is a product of local Hilbert spaces, each associated with\na link and the corresponding dual link. The two electric field operators\nassociated with the link-pair do not commute. In the non-compact case with\ngauge group $\\mathbb{R}$, each local Hilbert space is analogous to the one of a\ncharged \"particle\" moving in the link-pair group space $\\mathbb{R}^2$ in a\nconstant \"magnetic\" background field. In the compact case, the link-pair group\nspace is a torus $U(1)^2$ threaded by $k$ units of quantized \"magnetic\" flux,\nwith $k$ being the level of the Chern-Simons theory. The holonomies of the\ntorus $U(1)^2$ give rise to two self-adjoint extension parameters, which form\ntwo non-dynamical background lattice gauge fields that explicitly break the\nmanifest gauge symmetry from $U(1)$ to $\\mathbb{Z}(k)$. The local Hilbert space\nof a link-pair then decomposes into representations of a magnetic translation\ngroup. In the pure Chern-Simons limit of a large \"photon\" mass, this results in\na $\\mathbb{Z}(k)$-symmetric variant of Kitaev's toric code, self-adjointly\nextended by the two non-dynamical background lattice gauge fields. Electric\ncharges on the original lattice and on the dual lattice obey mutually anyonic\nstatistics with the statistics angle $\\frac{2 \\pi}{k}$. Non-Abelian $U(k)$\nBerry gauge fields that arise from the self-adjoint extension parameters may be\ninteresting in the context of quantum information processing."
    },
    {
        "anchor": "Twisted mass lattice QCD with non-degenerate quark masses: Quantum Chromodynamics on a lattice with Wilson fermions and a chirally\ntwisted mass term is considered in the framework of chiral perturbation theory.\nFor two and three numbers of quark flavours, respectively, with non-degenerate\nquark masses the pseudoscalar meson masses and decay constants are calculated\nin next-to-leading order including lattice effects quadratic in the lattice\nspacing a.",
        "positive": "Simulations of light scalar mesons on the lattice and related\n  difficulties: I review the lattice simulations of light scalar mesons with quark-antiquark\nand tetraquark interpolating fields. Several difficulties which complicate the\nextraction of scalar meson masses from the scalar correlators are pointed out.\nOne of the major difficulties is the presence of the two-pseudoscalar\nscattering states, which often dominate the correlator at light quark masses.\nIn the simulations with unphysical approximations such scattering contributions\nare even more disturbing since they are often large and sometimes negative.\nTechniques which allow extraction of scalar meson masses in presence of\nscattering states are listed. Preliminary results of various lattice\ncollaborations are presented."
    },
    {
        "anchor": "QCD thermodynamics with continuum extrapolated Wilson fermions II: We continue our investigation of 2+1 flavor QCD thermodynamics using\ndynamical Wilson fermions in the fixed scale approach. Two additional pion\nmasses, approximately 440 MeV and 285 MeV, are added to our previous work at\n545 MeV. The simulations were performed at 3 or 4 lattice spacings at each pion\nmass. The renormalized chiral condensate, strange quark number susceptibility\nand Polyakov loop is obtained as a function of the temperature and we observe a\ndecrease in the light chiral pseudo-critical temperature as the pion mass is\nlowered while the pseudo-critical temperature associated with the strange quark\nnumber susceptibility or the Polyakov loop is only mildly sensitive to the pion\nmass. These findings are in agreement with previous continuum results obtained\nin the staggered formulation.",
        "positive": "Schr\u00f6dinger functional at N_f=-2: We study the Schr\\\"odinger functional coupling for lattice Yang-Mills theory\ncoupled to an improved bosonic spinor field, which corresponds to QCD with\nminus two light flavors. This theory serves as a less costly testcase than QCD\nfor the scaling of the coupling."
    },
    {
        "anchor": "Four-dimensional Simulation of the Hot Electroweak Phase Transition with\n  the SU(2) Gauge-Higgs Model: We study the finite-temperature electroweak phase transition of the minimal\nstandard model within the four-dimensional SU(2) gauge-Higgs model. Monte Carlo\nsimulations are performed for intermediate values of the Higgs boson mass in\nthe range $50 \\lesssim M_H \\lesssim 100$GeV on a lattice with the temporal size\n$N_t=2$. The order of the transition is systematically examined using\nfinite-size scaling methods. Behavior of the interface tension and the latent\nheat for an increasing Higgs boson mass is also investigated. Our results\nsuggest that the first-order transition terminates around $M_H \\sim 80$GeV.",
        "positive": "$\u03c0^0$ to two-photon decay in lattice QCD: We calculate the neutral pion ($\\pi^0$) to off-shell two photon\n($\\gamma^*\\gamma^*$) transition form factor in lattice QCD. The transition form\nfactor can be extracted from the three-point function of the form\n(axial-vector)-(vector)-(vector) as a function of off-shell two-photon\nmomentum. Since the axial-anomaly plays an important role in the\n$\\pi^0\\to\\gamma\\gamma$ decay process, we employ the overlap fermion, which\npreserves the exact chiral symmetery on the lattice. After extrapolating to the\nchiral and the vanishing photon momentum limit with a fit function based on\nvector meson dominance (VMD) model, we find that the Adler-Bell-Jackiw anomaly\nis correctly reproduced."
    },
    {
        "anchor": "Pseudo-scalar meson form factors with maximally twisted Wilson fermions\n  at Nf = 2: We present preliminary results for various electroweak form factors of\npseudo-scalar mesons using the tree-level improved Symanzik gauge action and\nthe maximally twisted mass fermionic action with Nf = 2 dynamical flavors. Our\nresults, obtained for both light and heavy quark masses at a single lattice\nspacing (a ~ 0.09 fm) and at a single lattice volume (V * T = 24**3 * 48),\nexhibit a quite remarkable statistical precision thanks to the use of\nall-to-all quark propagators computed with a stochastic method. Moreover very\nlow values of the four-momentum transfer are achieved by making use of twisted\nboundary conditions on the valence quark fields. The mass dependence of the\npion charge radius is analyzed using Chiral Perturbation Theory, obtaining\nclear evidence of relevant two-loop contributions. The universal Isgur-Wise\nfunction is computed from heavy-to-heavy electromagnetic transitions and its\nslope in the case of $u(d)$ spectator quarks is found to be rho(IW)**2 = 0.77\n+/- 0.28, where the error is statistical only.",
        "positive": "Simple chromatic properties of gradient flow: It has become customary to use a smoothing algorithm called \"gradient flow\"\nto fix the lattice spacing in a simulation, through a parameter called $t_0$.\nIt is shown that in order to keep the length $t_0$ fixed with respect to\nmesonic or gluonic observables as the number of colors $N_c$ is varied, the\nfiducial point for the flow parameter must be scaled nearly linearly in $N_c$.\nIn simulations with dynamical fermions, the dependence of $t_0$ on the\npseudoscalar meson mass flattens as the number of colors rises, in a way which\nis consistent with large $N_c$ expectations."
    },
    {
        "anchor": "Phase Structure and Gauge Boson Propagator in the radially active 3D\n  compact Abelian Higgs Model: Unfreezing the radial degree of freedom, we study the three-dimensional\nAbelian Higgs model with compact gauge field and fundamentally charged matter.\nFor small quartic Higgs self coupling and finite gauge coupling the model\npossesses a first order transition from the confined/symmetric phase to the\ndeconfined/Higgs phase separated at some hopping parameter $\\kappa_c$. Latent\nheat and surface tension are obtained in the first order regime. At larger\nquartic coupling the first order transition ceases to exist, and the behavior\nbecomes similar to that known from the London limit. These observations are\ncomplemented by a study of the photon propagator in Landau gauge in the two\ndifferent regimes. The problems afflicting the gauge fixing procedure are\ncarefully investigated. We propose an improved gauge fixing algorithm which\nuses a finite subgroup in a preselection/preconditioning stage. The\ncomputational gain in the expensive confinement region is a speed-up factor\naround 10. The propagator in momentum space has a non-zero anomalous dimension\nin the confined phase whereas it vanishes in the Higgs phase. As far as the\ngauge boson propagator is concerned, we find that the radially active Higgs\nfield provides qualitatively no new effect compared to the radially frozen\nHiggs field studied before.",
        "positive": "Scattering from generalised lattice $\u03c6^4$ theory: We investigate numerically different techniques to extract scattering\namplitudes from the Euclidean Lattice {\\phi}4 theory with two fields, having\ndifferent masses. We present an exploratory study of the recently proposed\nmethod by Bruno and Hansen for extracting the scattering length from a\nfour-point function (cf 10.1007/JHEP06(2021)043), and a study of the two- and\nthree-particle quantization condition."
    },
    {
        "anchor": "Condensation phenomena in two-flavor scalar QED at finite chemical\n  potential: We study condensation in two-flavored, scalar QED with non-degenerate masses\nat finite chemical potential. The conventional formulation of the theory has a\nsign problem at finite density which can be solved using an exact reformulation\nof the theory in terms of dual variables. We perform a Monte Carlo simulation\nin the dual representation and observe a condensation at a critical chemical\npotential $\\mu_c$.\n  After determining the low-energy spectrum of the theory we try to establish a\nconnection between $\\mu_c$ and the mass of the lightest excitation of the\nsystem, which are naively expected to be equal. It turns out, however, that the\nrelation of the critical chemical potential to the mass spectrum in this case\nis non-trivial: Taking into account the form of the condensate and making some\nsimplifying assumptions we suggest an adequate explanation which is supported\nby numerical results.",
        "positive": "One-loop analyses of lattice QCD with the overlap Dirac operator: We discuss the weak coupling expansion of lattice QCD with the overlap Dirac\noperator. The Feynman rules for lattice QCD with the overlap Dirac operator are\nderived and the quark self-energy and vacuum polarization are studied at the\none-loop level. We confirm that their divergent parts agree with those in the\ncontinuum theory."
    },
    {
        "anchor": "Chiral Symmetry Restoration from a Boundary: The boundary of a manifold can alter the phase of a theory in the bulk. We\nexplore the possibility of a boundary-induced phase transition for the chiral\nsymmetry of QCD. In particular, we investigate the consequences of imposing\nhomogeneous Dirichlet boundary conditions on the quark fields. Such boundary\nconditions are sometimes employed in lattice gauge theory computations, for\nexample, when including external electromagnetic fields, or when computing\nquark propagators with a reduced temporal extent. Homogeneous Dirichlet\nboundary conditions force the chiral condensate to vanish at the boundary, and\nthereby obstruct the spontaneous breaking of chiral symmetry in the bulk. We\nshow the restoration of chiral symmetry due to a boundary is a non-perturbative\nphenomenon depending upon the mechanism of spontaneous symmetry breaking, and\nutilize the sigma model to exemplify the issues. Within this model, we find\nthat chiral symmetry is completely restored if the length of the compact\ndirection is less than 2.0 fm. For lengths greater than about 4 fm, an\napproximately uniform chiral condensate forms centered about the midpoint of\nthe compact direction. While the volume-averaged condensate approaches the\ninfinite volume value as the compact direction becomes very long, the\nfinite-size corrections are shown to be power law rather than exponential.",
        "positive": "The Oscillatory Behavior of the High-Temperature Expansion of Dyson's\n  Hierarchical Model: A Renormalization Group Analysis: We calculate 800 coefficients of the high-temperature expansion of the\nmagnetic susceptibility of Dyson's hierarchical model with a Landau-Ginzburg\nmeasure. Log-periodic corrections to the scaling laws appear as in the case of\na Ising measure. The period of oscillation appears to be a universal quantity\ngiven in good approximation by the logarithm of the largest eigenvalue of the\nlinearized RG transformation, in agreement with a possibility suggested by K.\nWilson and developed by Niemeijer and van Leeuwen. We estimate $\\gamma $ to be\n1.300 (with a systematic error of the order of 0.002) in good agreement with\nthe results obtained with other methods such as the $\\epsilon $-expansion. We\nbriefly discuss the relationship between the oscillations and the zeros of the\npartition function near the critical point in the complex temperature plane."
    },
    {
        "anchor": "Baryon spectrum in the composite sextet model: The strongly coupled near-conformal gauge theory with two fermion flavors in\nthe two-index symmetric (sextet) representation of SU(3) is potentially a\nminimal realization of the composite Higgs mechanism. We discuss the staggered\nfermion construction of baryonic states, present our first numerical results\nand comment on implications for dark matter.",
        "positive": "SU(3) Lattice QCD Study for Static Three-Quark Potential: We study the static three-quark (3Q) potential in detail using SU(3) lattice\nQCD with $12^3 \\times 24$ at $\\beta=5.7$ and $16^3 \\times 32$ at $\\beta=5.8,\n6.0$ at the quenched level. For more than 200 patterns of the 3Q systems, we\nnumerically derive 3Q ground-state potential $V_{3Q}$ from the 3Q Wilson loop\nwith the smearing technique, which reduces excited-state contaminations. The\nlattice QCD data of $V_{3Q}$ are well reproduced within a few % deviation by a\nsum of a constant, the two-body Coulomb term and the three-body linear\nconfinement term $\\sigma_{3Q} L_{min}$, with $L_{min}$ the minimal value of\ntotal length of color flux tubes linking the three quarks.\n  From the comparison with the Q-$\\bar {Q}$ potential, we find a universality\nof the string tension as $\\sigma_{3Q} \\simeq \\sigma_{\\rm Q \\bar Q}$ and the\none-gluon-exchange result for Coulomb coefficients, $A_{3Q} \\simeq \\frac12\nA_{\\rm Q \\bar Q}$."
    },
    {
        "anchor": "Phase of the Wilson Line: This paper discusses the global $Z(N)$ symmetry of finite-temperature,\n$SU(N)$, pure Yang-Mills lattice gauge theory and the physics of the phase of\nthe Wilson line expectation value. In the high $T$ phase, $\\langle L \\rangle$\ntakes one of $N$ distinct values proportional to the $Nth$ roots of unity in\n$Z(N)$, and the $Z(N)$ symmetry is broken. Only one of these is consistent with\nthe usual interpretation $\\langle L \\rangle = e^{-F/T}$. This relation should\nbe generalized to $\\langle L \\rangle = z e^{-F/T}$ with $z \\in Z(N)$ so that it\nis consistent with the negative or complex values. In the Hamiltonian\ndescription, the {\\em physical} variables are the group elements on the links\nof the spatial lattice. In a Lagrangian formulation, there are also group\nelements on links in the inverse-temperature direction from which the Wilson\nline is constructed. These are unphysical, auxiliary variables introduced to\nenforce the Gauss law constraints. The following results are obtained: The\nrelation $\\langle L \\rangle=ze^{-F/T}$ is derived. The value of $z \\in Z(N)$ is\ndetermined by the external field that is needed for the infinite-volume limit.\nThere is a single physical, high-temperature phase, which is the same for all\n$z$. The global $Z(N)$ symmetry is not physical; it acts as the identity on all\nphysical states. In the Hamiltonian formulation, the high-temperature phase is\nnot distinguished by physical broken symmetry but rather by percolating flux.",
        "positive": "Cutoff effects in meson spectral functions: We study the lattice spacing dependence of meson spectral functions\ncalculated in quenched QCD with domain wall fermions as well as clover Wilson\nfermions in quenched and partially-quenched QCD. We conclude that for lattice\nspacing $a \\le 3$ GeV all excited states appearing in the spectral functions\nare lattice artifacts."
    },
    {
        "anchor": "Interpolated Lattice Gauge Fields and Chiral Fermions in the Schwinger\n  Model: The effective action induced by fermions in the chiral Schwinger model with\ncharges (3,4,5) is investigated. Pauli-Villars regularization is combined with\nmomentum cut-off for the evaluation of the fermion determinants on continuum\ngauge fields interpolated between lattice points. The convergence and gauge\nvariance are studied numerically on gauge configurations taken from quenched\nupdating.",
        "positive": "Gluon gravitational form factors of the nucleon and the pion from\n  lattice QCD: A future Electron-Ion Collider will enable the gluon contributions to the\ngravitational form factors of the proton to be constrained experimentally for\nthe first time. Here, the first calculation of these form factors from lattice\nQuantum Chromodynamics is presented. The calculations use a\nlarger-than-physical value of the light quark mass corresponding to $m_\\pi \\sim\n450$ MeV. All three form factors, which encode the momentum-dependence of the\nlowest moment of the spin independent gluon generalised parton distributions\nand are related to different components of the energy-momentum tensor, are\nresolved. In particular, the gluon $D$-term form factor, related to the\npressure distribution inside the nucleon, is determined for the first time. The\ngluon contributions to the two gravitational form factors of the pion are also\ndetermined, and are compared to existing lattice determinations of the quark\ncontributions to the gravitational form factors and to phenomenology."
    },
    {
        "anchor": "Beyond the quark model of hadrons from lattice QCD: Lattice QCD can give direct information on OZI-violating contributions to\nmesons. Here we explore the contributions that split flavour singlet and\nnon-singlet meson masses. I discuss in detail the spectrum and decays for\nscalar mesons (ie including glueball effects). I also review the status of\nhybrid mesons and their decays.",
        "positive": "The Chiral Extension of Lattice QCD: The chiral extension of Quantum Chromodynamics (XQCD) adds to the standard\nlattice action explicit pseudoscalar meson fields for the chiral condensates.\nWith this action, it is feasible to do simulations at the chiral limit with\nzero mass Goldstone modes. We review the arguments for why this is expected to\nbe in the same universality class as the traditional action. We present\npreliminary results on convergence of XQCD for naive fermions and on the\nmethodology for introducing counter terms to restore chiral symmetry for Wilson\nfermions."
    },
    {
        "anchor": "Simulating QCD at finite density: In this review, I recall the nature and the inevitability of the \"sign\nproblem\" which plagues attempts to simulate lattice QCD at finite baryon\ndensity. I present the main approaches used to circumvent the sign problem at\nsmall chemical potential. I sketch how one can predict analytically the\nseverity of the sign problem, as well as the numerically accessible range of\nbaryon densities. I review progress towards the determination of the\npseudo-critical temperature T_c(mu), and towards the identification of a\npossible QCD critical point. Some promising advances with non-standard\napproaches are reviewed.",
        "positive": "Determination of hybrid charmonium meson masses: We report initial results from our study of the masses and decay constants of\nthe lightest multiplet of charmonium-like hybrid mesons. We obtain precise\nmeasurements of the $1^{-+}$ state through the use of a variational basis and a\nlarge number of configurations at three lattice spacings. We use staggered\nfermion operators using configurations generated with the HISQ action with\n2+1+1 dynamical flavours. The mixing of the vector hybrid with the $J/\\psi$ is\nexamined and a preliminary bound on the vector hybrid decay constant is\npresented."
    },
    {
        "anchor": "Apparent convergence of Pad\u00e9 approximants for the crossover line in\n  finite density QCD: We propose a novel Bayesian method to analytically continue observables to\nreal baryochemical potential $\\mu_B$ in finite density QCD. Taylor coefficients\nat $\\mu_B=0$ and data at imaginary chemical potential $\\mu_B^I$ are treated on\nequal footing. We consider two different constructions for the Pad\\'e\napproximants, the classical multipoint Pad\\'e approximation and a mixed\napproximation that is a slight generalization of a recent idea in Pad\\'e\napproximation theory. Approximants with spurious poles are excluded from the\nanalysis. As an application, we perform a joint analysis of the available\ncontinuum extrapolated lattice data for both pseudocritical temperature $T_c$\nat $\\mu_B^I$ from the Wuppertal-Budapest Collaboration and Taylor coefficients\n$\\kappa_2$ and $\\kappa_4$ from the HotQCD Collaboration. An apparent\nconvergence of $[p/p]$ and $[p/p+1]$ sequences of rational functions is\nobserved with increasing $p.$ We present our extrapolation up to $\\mu_B\\approx\n600$ MeV.",
        "positive": "Tetraquark resonances computed with static lattice QCD potentials and\n  scattering theory: We study tetraquark resonances with lattice QCD potentials computed for two\nstatic quarks and two dynamical quarks, the Born-Oppenheimer approximation and\nthe emergent wave method of scattering theory. As a proof of concept we focus\non systems with isospin $I = 0$, but consider different relative angular\nmomenta $l$ of the heavy $b$ quarks. We compute the phase shifts and search for\n$\\mbox{S}$ and $\\mbox{T}$ matrix poles in the second Riemann sheet. We predict\na new tetraquark resonance for $l = 1$, decaying into two $B$ mesons, with\nquantum numbers $I(J^P) = 0(1^-)$, mass $m = 10576_{-4}^{+4} \\, \\textrm{MeV}$\nand decay width $\\Gamma = 112_{-103}^{+90} \\, \\textrm{MeV}$."
    },
    {
        "anchor": "The strongly interacting Quark Gluon Plasma, and the critical behaviour\n  of QCD at imaginary chemical potential: We explore the highly non-perturbative hot region of the QCD phase diagram\nclose to Tc by use of an imaginary chemical potential mu which avoids the sign\nproblem. The number density and the quark number susceptibility are consistent\nwith a critical behaviour associated with the transition line in the negative\nmu^2 half-plane. We compare the analytic continuation of these results with\nvarious phenomenological models, none of which provides a satisfactory\ndescription of data, a failure on which we make some comments. These results\ncomplement and extend the information obtained via the analysis of the\nsusceptibilities evaluated at zero mu, yielding a simple description of the\ncandidate strongly interacting QGP phase. As a byproduct of our analysis we\ninvestigate the Polyakov loop and its hermitian conjugate. Our data offer a\nvivid evidence of the importance of the complex nature of the functional\nintegral measure, which results in L (mu) ne \\bar L(mu) for a real chemical\npotential.",
        "positive": "Negative-Energy Spinors and the Fock Space of Lattice Fermions at Finite\n  Chemical Potential: Recently it was suggested that the problem of species doubling with\nKogut-Susskind lattice fermions entails, at finite chemical potential, a\nconfusion of particles with antiparticles. What happens instead is that the\nfamiliar correspondence of positive-energy spinors to particles, and of\nnegative-energy spinors to antiparticles, ceases to hold for the Kogut-Susskind\ntime derivative. To show this we highlight the role of the spinorial ``energy''\nin the Osterwalder-Schrader reconstruction of the Fock space of non-interacting\nlattice fermions at zero temperature and nonzero chemical potential. We\nconsider Kogut-Susskind fermions and, for comparison, fermions with an\nasymmetric one-step time derivative."
    },
    {
        "anchor": "Deconfinement from Action Restriction: The effect of restricting the plaquette to be greater than a certain cutoff\nvalue is studied. The action considered is the standard Wilson action with the\naddition of a plaquette restriction, which should not affect the continuum\nlimit of the theory. In this investigation, the strong coupling limit is also\ntaken. It is found that a deconfining phase transition occurs as the cutoff is\nincreased, on all lattices studied (up to $20^4$). The critical cutoff on the\ninfinite lattice appears to be around 0.55. For cutoffs above this, a fixed\npoint behavior is observed in the normalized fourth cumulant of the Polyakov\nloop, suggesting the existence of a line of critical points corresponding to a\nmassless gluon phase, not unlike the situation in compact U(1). The Polyakov\nloop susceptibility also appears to be diverging with lattice size at these\ncutoffs. A strong finite volume behavior is observed in the pseudo-specific\nheat. It is discussed whether these results could still be consistent with the\nstandard crossover picture which precludes the existence of a deconfining phase\ntransition on an infinite symmetric lattice.",
        "positive": "Lattice perturbation theory for the null cusp string: We reconsider the problem of discretising the worldsheet for the gauge-fixed\nGreen-Schwarz superstring on a null cusp background, and present a setup which\nfully preserves its global $U(1)\\times SU(4)$ symmetry. We discuss divergences\nby power counting on the lattice, and study renormalizability at one loop with\nthe example of one-point functions and one bosonic correlator of the worldsheet\nexcitations. In order to remove UV divergences at one loop, it is necessary to\nintroduce two extra parameters in the action, which need to be either\nfine-tuned at tree level or renormalized at one-loop."
    },
    {
        "anchor": "Critical Phenomena with Linked Cluster Expansions in a Finite Volume: Linked cluster expansions are generalized from an infinite to a finite\nvolume. They are performed to 20th order in the expansion parameter to approach\nthe critical region from the symmetric phase. A new criterion is proposed to\ndistinguish 1st from 2nd order transitions within a finite size scaling\nanalysis. The criterion applies also to other methods for investigating the\nphase structure such as Monte Carlo simulations. Our computational tools are\nillustrated at the example of scalar O(N) models with four and six-point\ncouplings for $N=1$ and $N=4$ in three dimensions. It is shown how to localize\nthe tricritical line in these models. We indicate some further applications of\nour methods to the electroweak transition as well as to models for\nsuperconductivity.",
        "positive": "Static Scaling Behavior of High-Molecular-Weight Polymers in Dilute\n  Solution: A Reexamination: Previous theories of dilute polymer solutions have failed to distinguish\nclearly between two very different ways of taking the long-chain limit: (I) $N\n\\to\\infty$ at fixed temperature $T$, and (II) $N \\to\\infty$, $T \\to T_\\theta$\nwith $x \\equiv N^\\phi (T-T_\\theta)$ fixed. I argue that the modern\ntwo-parameter theory (continuum Edwards model) applies to case II --- not case\nI --- and in fact gives exactly the crossover scaling functions for $x \\ge 0$\nmodulo two nonuniversal scale factors. A Wilson-type renormalization group\nclarifies the connection between crossover scaling functions and continuum\nfield theories. [Also contains a general discussion of the connection between\nthe Wilson and field-theoretic renormalization groups. Comments solicited.]"
    },
    {
        "anchor": "Aspects of determining fBs: scaling and power-law divergences: We present preliminary results for the decay constant of the Bs meson, fBs,\nat three values of beta=5.7, 6.0 and 6.2 using NRQCD and clover fermions for\nthe heavy and light quarks respectively. As a consistency check the decay\nconstant has also been extracted from the axial-vector current at finite\nmomentum. In addition, we discuss the cancellation of O(alpha/(aM0)) terms and\nthe remaining uncertainty in fBs from higher order divergences.",
        "positive": "A Study of Practical Implementations of the Overlap-Dirac Operator in\n  Four Dimensions: We study three practical implementations of the Overlap-Dirac operator $D_o=\n(1/2) [1 + \\gamma_5\\epsilon(H_w)]$ in four dimensions. Two implementations are\nbased on different representations of $\\epsilon(H_w)$ as a sum over poles. One\nof them is a polar decomposition and the other is an optimal fit to a ratio of\npolynomials. The third one is obtained by representing $\\epsilon(H_w)$ using\nGegenbauer polynomials and is referred to as the fractional inverse method.\nAfter presenting some spectral properties of the Hermitian operator\n$H_o=\\gamma_5 D_o$, we study its spectrum in a smooth SU(2) instanton\nbackground with the aim of comparing the three implementations of $D_o$. We\nalso present some results in SU(2) gauge field backgrounds generated at\n$\\beta=2.5$ on an $8^4$ lattice. Chiral properties have been numerically\nverified."
    },
    {
        "anchor": "Non-perturbative analysis, Gribov horizons and the boundary of the\n  fundamental domain: In this contribution to the proceedings we will describe some of the details\nfor constructing the Gribov horizon and the boundary of the fundamental modular\ndomain, when restricting to some low energy modes of pure SU(2) gauge theory in\na spherical spatial geometry. The fundamental domain is a one-to-one\nrepresentation of the set of gauge invariant degrees of freedom, in terms of\ntransverse gauge fields. Boundary identifications are the only remnants of the\nGribov copies.",
        "positive": "Separating perturbative and non-perturbative contributions to the\n  plaquette: We try to separate the perturbative and non-perturbative contributions to the\nplaquette of pure SU(3) gauge theory. To do this we look at the large-n\nasymptotic behaviour of the perturbation series in order to estimate the\ncontribution of the as-yet uncalculated terms in the series. We find no\nevidence for the previously reported Lambda^2 contribution to the gluon\ncondensate. Attempting to determine the conventional Lambda^4 condensate gives\na value of approximately 0.03(2) GeV^4, in reasonable agreement with sum rule\nestimates, though with very large uncertainties."
    },
    {
        "anchor": "Compact U(1) Lattice Gauge-Higgs Theory with Monopole Suppression: We investigate a model of a U(1)-Higgs theory on the lattice with compact\ngauge fields but completely suppressed (elementary) monopoles. We study the\nmodel at two values of the quartic Higgs self-coupling, a strong coupling,\n$\\lambda = 3.0$, and a weak coupling, $\\lambda=0.01$. We map out the phase\ndiagrams and find that the monopole suppression eliminated the confined phase\nof the standard lattice model at strong gauge coupling. We perform a detailed\nanalysis of the static potential and study the mass spectrum in the Coulomb and\nHiggs phases for three values of the gauge coupling. We also probe the\nexistence of a scalar bosonium to the extent that our data allow and conclude\nthat further investigations are required in the Coulomb phase.",
        "positive": "Vacuum Expectation Values of Twisted Mass Fermion Operators: Using noise methods on a quenched $20^3 \\times 32$ lattice at $\\beta=6.0$, we\nhave investigated vacuum expectation values and relative linear correlations\namong the various Wilson and twisted mass scalar and pseudoscalar disconnected\nloop operators. We show results near the maximal twist lines in $\\kappa$, $\\mu$\nparameter space, either defined as the absence of parity mixing or the\nvanishing of the PCAC quark mass."
    },
    {
        "anchor": "Investigation of Laplacian Gauge Fixing for U(1) and SU(2) Gauge Fields: The Laplacian gauge on the lattice is investigated numerically using U(1) and\nSU(2) gauge fields. The problem of Gribov ambiguities is addressed and to asses\nthe smoothness of the gauge fixed configurations, they are compared to\nconfigurations fixed to the Landau gauge. The results of these comparisons with\nthe Landau gauge indicate that Laplacian gauge fixing works very well in\npractice and offers a viable alternative to Landau gauge fixing.",
        "positive": "First direct lattice-QCD calculation of the $x$-dependence of the pion\n  parton distribution function: We present the first direct lattice-QCD calculation of the Bjorken-$x$\ndependence of the valence quark distribution of the pion. Using large-momentum\neffective theory (LaMET), we calculate the boosted pion state with long Wilson\nlink operators. After implementing the one-loop matching and meson mass\ncorrections, our result at $m_\\pi \\approx 310$ MeV is in agreement with those\nextracted from experimental data as well as from Dyson-Schwinger equation in\nsmall $x$ region, but a sizeable discrepancy in the large $x$ region. This\ndiscrepancy provides a nice opportunity to systematically study and disentangle\nthe artifacts in the LaMET approach, which will eventually help to discern\nvarious existing analyses in the literature."
    },
    {
        "anchor": "Topological properties of $CP^{N-1}$ models in the large-$N$ limit: We investigate, by numerical simulations on a lattice, the\n$\\theta$-dependence of 2$d$ $CP^{N-1}$ models for a range of $N$ going from 9\nto 31, combining imaginary $\\theta$ and simulated tempering techniques to\nimprove the signal-to-noise ratio and alleviate the critical slowing down of\nthe topological modes. We provide continuum extrapolations for the second and\nfourth order coefficients in the Taylor expansion in $\\theta$ of the vacuum\nenergy of the theory, parameterized in terms of the topological susceptibility\n$\\chi$ and of the so-called $b_2$ coefficient. Those are then compared with\navailable analytic predictions obtained within the $1/N$ expansion, pointing\nout that higher order corrections might be relevant in the explored range of\n$N$, and that this fact might be related to the non-analytic behavior expected\nfor $N = 2$. We also consider sixth-order corrections in the $\\theta$\nexpansion, parameterized in terms of the so-called $b_4$ coefficient: in this\ncase our present statistical accuracy permits to have reliable non-zero\ncontinuum estimations only for $N \\leq 11$, while for larger values we can only\nset upper bounds. The sign and values obtained for $b_4$ are compared to\nlarge-$N$ predictions, as well as to results obtained for $SU(N_c)$ Yang-Mills\ntheories, for which a first numerical determination is provided in this study\nfor the case $N_c = 2$.",
        "positive": "QED and strong isospin corrections in the hadronic vacuum polarization\n  contribution to the anomalous magnetic moment of the muon: Recently, the Budapest-Marseille-Wuppertal collaboration achieved sub-percent\nprecision in the evaluation of the lowest-order hadronic vacuum polarization\ncontribution to the muon $g_\\mu-2$ (arXiv:hep-lat/2002.12347v3). At this level\nof precision, isospin-symmetric QCD is not sufficient. In this contribution we\nreview how QED and strong-isospin-breaking effects have been included in our\nwork. Isospin breaking is implemented by expanding the relevant correlation\nfunctions to second order in the electric charge $e$ and to first order in\n$m_u-m_d$. The correction terms are then computed using isospin-symmetric\nconfigurations. The choice of this approach allows us to better distribute the\navailable computing resources among the various contributions."
    },
    {
        "anchor": "Tensor network representation of non-abelian gauge theory coupled to\n  reduced staggered fermions: We show how to construct a tensor network representation of the path integral\nfor reduced staggered fermions coupled to a non-abelian gauge field in two\ndimensions. The resulting formulation is both memory and computation efficient\nbecause reduced staggered fermions can be represented in terms of a minimal\nnumber of tensor indices while the gauge sector can be approximated using\nGaussian quadrature with a truncation. Numerical results obtained using the\nGrassmann TRG algorithm are shown for the case of $SU(2)$ lattice gauge theory\nand compared to Monte Carlo results.",
        "positive": "Quark Mass Dependence of the QCD Equation of State on N_tau=8 Lattices: We currently perform calculations with an improved staggered fermion action\n(p4fat3). We use a strange quark mass that has been tuned to its physical value\nand light quarks of mass m_s/20 on lattices of size 32^3x8. This corresponds to\nan almost physical light quark mass. We present first results on the low\ntemperature part of the equation of state of QCD. Through comparison with the\npreliminary hotQCD results on the N_tau=8 equation of state, which have been\nobtained with twice heavier light quark masses, we can quantify the quark mass\ndependence of the equation of state in the low temperature regime. We also\ncomment on the quark mass dependence of the equation of state at high\ntemperature."
    },
    {
        "anchor": "On the Universality of Certain Non-Renormalizable Contributions in\n  Two-Dimensional Quantum Field Theory: We consider the question of removing the ultraviolet cutoff in a 2D Quantum\nField Theory with an interaction term which is non-renormalizable by power\ncounting. This model arises as the first non-trivial correction beyond the\nGaussian approximation of the so called Capillary Wave or Drumhead Model, and\nis rather important from a physical point of view since it correctly describes\nthe finite size effects of two-dimensional interfaces. Despite the fact that\nthe interaction is non-renormalizable, we prove that for a large class of\nregularization schemes the finite and divergent parts can be separated in a\nsimple way. Furthermore, the finite part is independent of the choice of cutoff\nprescription used.",
        "positive": "Non-perturbative renormalization in coordinate space for $N_f=2$\n  maximally twisted mass fermions with tree-level Symanzik improved gauge\n  action: We present results of a lattice QCD application of a coordinate space\nrenormalization scheme for the extraction of renormalization constants for\nflavour non-singlet bilinear quark operators. The method consists in the\nanalysis of the small-distance behaviour of correlation functions in Euclidean\nspace and has several theoretical and practical advantages, in particular: it\nis gauge invariant, easy to implement and has relatively low computational\ncost. The values of renormalization constants in the X-space scheme can be\nconverted to the MSbar scheme via 4-loop continuum perturbative formulae. Our\nresults for $N_f=2$ maximally twisted mass fermions with tree-level Symanzik\nimproved gauge action are compared to the ones from the RI-MOM scheme and show\nfull agreement with this method."
    },
    {
        "anchor": "Disconnected contribution to the LO HVP term of muon g-2 from ETMC: We present a lattice determination of the disconnected contributions to the\nleading-order hadronic vacuum polarization (HVP) to the muon anomalous magnetic\nmoment in the so-called short and intermediate time-distance windows. We employ\ngauge ensembles produced by the Extended Twisted Mass Collaboration (ETMC) with\n$N_f = 2 + 1 + 1$ flavours of Wilson twisted-mass clover-improved quarks with\nmasses approximately tuned to their physical value. We take the continuum limit\nemploying three lattice spacings at about 0.08, 0.07 and 0.06 fm.",
        "positive": "Finite-temperature study of eight-flavor SU(3) gauge theory: We present new lattice investigations of finite-temperature transitions for\nSU(3) gauge theory with Nf=8 light flavors. Using nHYP-smeared staggered\nfermions we are able to explore renormalized couplings $g^2 \\lesssim 20$ on\nlattice volumes as large as $48^3 \\times 24$. Finite-temperature transitions at\nnon-zero fermion mass do not persist in the chiral limit, instead running into\na strongly coupled lattice phase as the mass decreases. That is,\nfinite-temperature studies with this lattice action require even larger $N_T >\n24$ to directly confirm spontaneous chiral symmetry breaking."
    },
    {
        "anchor": "Settling an old story: solution of the Thirring model in thimble\n  regularization: Thimble regularisation of lattice field theories has been proposed as a\nsolution to the infamous sign problem. It is conceptually very clean and\npowerful, but it is in practice limited by a potentially very serious issue: in\ngeneral many thimbles can contribute to the computation of the functional\nintegrals. Semiclassical arguments would suggest that the fundamental thimble\ncould be sufficient to get the correct answer, but this hypothesis has been\nproven not to hold true in general. A first example of this failure has been\nput forward in the context of the Thirring model: the dominant thimble\napproximation is valid only in given regions of the parameter space of the\ntheory. Since then a complete solution of this (simple) model in thimble\nregularisation has been missing. In this paper we show that a full solution\n(taking the continuum limit) is indeed possible. It is possible thanks to a\nmethod we recently proposed which de facto evades the need to simulate on many\nthimbles.",
        "positive": "Instanton size distribution in O(3): We present calculations of the size distribution of instantons in the 2d O(3)\nnon-linear sigma-model, and briefly discuss the effects cooling has upon the\nconfigurations and the topological objects. (This preprint is also available\nvia anonymous ftp to suna.amtp.liv.ac.uk in /pub/pss/ as instdist.uue.)"
    },
    {
        "anchor": "Locality of the overlap-Dirac operator on topology-fixed gauge\n  configurations: We investigate the locality property of the overlap-Dirac operator on gauge\nconfigurations generated with extra Wilson fermions. By such extra terms we\nexpect that the structure of the Aoki phase would change drastically. In\nparticular, we study the possibility of defining the overlap-Dirac operator in\nthe strong coupling regime keeping its exponential locality.",
        "positive": "Numerical Study of the Ghost-Ghost-Gluon Vertex on the Lattice: It is well known that, in Landau gauge, the renormalization function of the\nghost-ghost-gluon vertex \\widetilde{Z}_1(p^2) is finite and constant, at least\nto all orders of perturbation theory. On the other hand, a direct\nnon-perturbative verification of this result using numerical simulations of\nlattice QCD is still missing. Here we present a preliminary numerical study of\nthe ghost-ghost-gluon vertex and of its corresponding renormalization function\nusing Monte Carlo simulations in SU(2) lattice Landau gauge. Data were obtained\nin 4 dimensions for lattice couplings beta = 2.2, 2.3, 2.4 and lattice sides N\n= 4, 8, 16."
    },
    {
        "anchor": "On the prediction of spectral densities from Lattice QCD: Hadronic spectral densities play a pivotal role in particle physics, a prime\nexample being the R-ratio defined from electron-positron scattering into\nhadrons. To predict them from first principles using Lattice QCD, we face a\nnumerically ill-posed inverse problem, due to the Euclidean signature adopted\nin practical simulations. Here we present a recent numerical analysis of the\nvector isovector spectral density extracted using the multi-level algorithm\n(recently extended also to the case of dynamical fermions) and discuss its\nimplications.",
        "positive": "Exploring confinement by cooling: A study of compact QED$_3$: The role of monopoles in the confining behavior of compact lattice $QED_3$ is\nstudied using an adiabatic cooling method. Monopole-antimonopole pairs with\nlarge separation suvive cooling and the presence or absence of such plasma\nmonopoles provides a useful classification of the lattice gauge field\nconfigurations at large $\\beta$. By calculating observables in subsets of gauge\nfield configurations which contain or do not contain plasma monopoles it is\nseen that, in compact $QED_3$, monopoles dominate the long distance physics,\ne.g., the string tension, linear confining potential and dynamical mass\ngeneration. On the other hand, the spin-spin interaction is essentially\nunaffected by monopoles."
    },
    {
        "anchor": "Thermal modifications of charmonia and bottomonia from spatial\n  correlation functions: We present our study on the thermal modifications of charmonia and bottomonia\nfrom spatial correlation functions at zero and nonzero momenta in quenched QCD.\nTo accommodate the heavy quarks on the lattice we performed simulations on very\nfine lattices at a fixed beta value corresponding to a lattice spacing\n$a^{-1}=22.8$ GeV on $192^3\\times32$, $192^3\\times48$, $192^3\\times56$,\n$192^3\\times64$ and $192^3\\times96$ lattices using clover-improved Wilson\nfermions. These lattices correspond to temperatures of $2.25 T_c$, $1.50 T_c$,\n$1.25 T_c$, $1.10 T_c$ and $0.75 T_c$. To increase the signal to noise ratio in\nthe axial-vector and scalar channels we used multi-sources for the measurement\nof spatial correlation functions. By investigating on the differences between\nspatial and temporal correlators as well as the temperature dependence of\nscreening masses we will discuss the thermal effects in different channels of\nquarkonium states. Besides this the dispersion relation of the screening mass\nat different momenta is also discussed.",
        "positive": "Lattice QCD at finite temperature: Evidence for calorons from the\n  eigenvectors of the Dirac operator: We analyze the eigenvalues and eigenvectors of the staggered Dirac operator\nin quenched lattice QCD in the vicinity of the deconfinement phase transition\nusing the L\\\"uscher-Weisz gauge action. The spectral and localization\nproperties of the low-lying eigenmodes show characteristic differences between\nthe Z_3 sectors above the critical temperature T_c. These findings can be\ninterpreted in terms of calorons."
    },
    {
        "anchor": "Chiral Anomaly on a Lattice: A calculation of the chiral anomaly on a finite lattice without fermion\ndoubling is presented . The lattice gauge field is defined in the spirit of\nnoncommutative geometry. Standard formulas for the continuum anomaly are\nobtained as a limit.",
        "positive": "Light and strange quark masses from $N_f=2+1$ simulations with Wilson\n  fermions: We present a nearly final analysis of the $u/d$ and $s$ quark masses,\nextracted using the PCAC quark masses reported in [PRD 95 (2017) 074504]. The\ndata is based on the CLS $N_f = 2 + 1$ simulations with Wilson/Clover quarks\nand L\\\"uscher-Weisz gauge action, at four $\\beta$ values (i.e. lattice\nspacings) and a range of quark masses. We use the ALPHA results of [EPJC 78\n(2018) 387] for non-perturbative quark mass renormalisation and RG-running from\nhadronic to electroweak scales in the Schr\\\"odinger Functional scheme. Quark\nmasses are quoted both in the $\\overline{\\rm MS}$ scheme and as RGI quantities."
    },
    {
        "anchor": "5-dimensional SU(2) lattice gauge theory with Z2 orbifolding and its\n  phase structure: In an SU(2) lattice gauge theory with a Z2 orbifolded extra dimension, the\nnew symmetry which is called as a stick symmetry is useful in understanding the\nbulk transition. We discuss the relation with the Fradkin-Shenker's phase\ndiagram as well. A remnant of the extra dimension is remained as two U(1) gauge\nsymmetries in two 4-dimensional spaces. We also consider more general bulk\ngauge groups beyond SU(2).",
        "positive": "B_K with two flavors of dynamical overlap fermions: We present a two-flavor QCD calculation of $B_K$ on a $16^3 \\times 32$\nlattice at $a\\sim 0.12$ fm (or equivalently $a^{-1}\\sim$1.67 GeV). Both valence\nand sea quarks are described by the overlap fermion formulation. The matching\nfactor is calculated non-perturbatively with the so-called RI/MOM scheme. We\nfind that the lattice data are well described by the next-to-leading order\n(NLO) partially quenched chiral perturbation theory (PQChPT) up to around a\nhalf of the strange quark mass ($m_s^{\\rm phys}/2$). The data at quark masses\nheavier than $m_s^{\\rm phys}/2$ are fitted including a part of\nnext-to-next-to-leading order terms. We obtain $B_K^{\\bar{\\rm MS}}(2 {\\rm\nGeV})= 0.537(4)(40)$, where the first error is statistical and the second is an\nestimate of systematic uncertainties from finite volume, fixing topology, the\nmatching factor, and the scale setting."
    },
    {
        "anchor": "Overlap Dirac operator with chiral chemical potential and Chiral\n  Magnetic Effect on the lattice: A self-consistent construction of the overlap lattice Dirac operator coupled\nto chiral chemical potential is proposed. With the help of the constructed\noperator we compute electric current induced by a constant magnetic field\n(Chiral Magnetic Effect). We find that the result disagrees with the one\npredicted by anomaly-based arguments and comment on the origin of this\ndiscrepancy. We demonstrate that a straightforward lattice calculation with a\nconstant magnetic field and a uniform chiral chemical potential in fact\ncorresponds to an infrared singularity in the dimensionally reduced\npolarization tensor and hence yields the result which is extremely sensitive to\ninfrared regulators such as finite volume or finite temperature.",
        "positive": "Towards the equation of state in 2+1 flavor QCD with improved Wilson\n  quarks in the fixed scale approach: We report on the status of our study towards the equation of state in 2+1\nflavor QCD with improved Wilson quarks. To reduce the computational cost which\nis quite demanding for Wilson-type quarks, we adopt the fixed scale approach,\ni.e. the temperature T is varied by N_t at fixed lattice spacing. Since the\nconventional integral method to obtain the pressure is inapplicable at a fixed\nscale, we adopt the \"T-integral method\", to calculate the pressure\nnon-perturbatively. Reduction of the computational cost of T=0 simulations thus\nachieved is indispensable to study EOS in QCD with dynamical quarks."
    },
    {
        "anchor": "PNJL model for adjoint fermions: Recent work on QCD-like theories has shown that the addition of adjoint\nfermions obeying periodic boundary conditions to gauge theories on R^3 X S^1\ncan lead to a restoration of center symmetry and confinement for sufficiently\nsmall circumference L of S^1. At small L, perturbation theory may be used\nreliably to compute the effective potential for the Polyakov loop P in the\ncompact direction. Periodic adjoint fermions act in opposition to the gauge\nfields, which by themselves would lead to a deconfined phase at small L. In\norder for the fermionic effects to dominate gauge field effects in the\neffective potential, the fermion mass must be sufficiently small. This\nindicates that chiral symmetry breaking effects are potentially important. We\ndevelop a Polyakov-Nambu-Jona Lasinio (PNJL) model which combines the known\nperturbative behavior of adjoint QCD models at small L with chiral symmetry\nbreaking effects to produce an effective potential for the Polyakov loop P and\nthe chiral order parameter psi-bar psi. A rich phase structure emerges from the\neffective potential. Our results are consistent with the recent lattice\nsimulations of Cossu and D'Elia, which found no evidence for a direct\nconnection between the small-L and large-L confining regions. Nevertheless, the\ntwo confined regions are connected indirectly if an extended field theory model\nwith an irrelevant four-fermion interaction is considered. Thus the small-L and\nlarge-L regions are part of a single confined phase.",
        "positive": "The Elusive Asymptotic Behavior of the High-Temperature Expansion of the\n  Hierarchical Ising Model: We present a differential formulation of the recursion formula of the\nhierarchical model which provides a recursive method of calculation for the\nhigh-temperature expansion. We calculate the first 30 coefficients of the high\ntemperature expansion of the magnetic susceptibility of the Ising hierarchical\nmodel with 12 significant digits. We study the departure from the approximation\nwhich consists of identifying the coefficients with the values they would take\nif a $[0,1]$ Pad\\'e approximant were exact. We show that, when the order in the\nhigh-temperature expansion increases, the departure from this approximation\ngrows more slowly than for nearest neighbor models. As a consequence, the value\nof the critical exponent $\\gamma $ estimated using Pad\\'e approximants\nconverges very slowly and the estimations using 30 coefficients have errors\nlarger than 0.05. A (presumably much) larger number of coefficients is\nnecessary to obtain the critical exponents with a precision comparable to the\nprecision obtained for nearest neighbor models with less coefficients. We also\ndiscuss the possibility of constructing models where a $[0,1]$ Pad\\'e\napproximant would be exact."
    },
    {
        "anchor": "Quarkonia in a deconfined gluonic plasma: We discuss lattice results on the properties of finite momentum charmonium\nstates in a gluonic plasma. We also present preliminary results for bottomonium\ncorrelators and spectral functions in the plasma. Significant modifications of\nchi_b states are seen at temperatures of 1.5 Tc.",
        "positive": "Applications of the Feynman-Hellmann theorem in hadron structure: The Feynman-Hellmann (FH) relation offers an alternative way of accessing\nhadronic matrix elements through artificial modifications to the QCD\nLagrangian. In particular, a FH-motivated method provides a new approach to\ncalculations of disconnected contributions to matrix elements and high-momentum\nnucleon and pion form factors. Here we present results for the total nucleon\naxial charge, including a statistically significant non-negative total\ndisconnected quark contribution of around $-5\\%$ at an unphysically heavy pion\nmass. Extending the FH relation to finite-momentum transfers, we also present\ncalculations of the pion and nucleon electromagnetic form factors up to\nmomentum transfers of around 7-8 GeV$^2$. Results for the nucleon are not able\nto confirm the existence of a sign change for the ratio $\\frac{G_E}{G_M}$, but\nsuggest that future calculations at lighter pion masses will provide\nfascinating insight into this behaviour at large momentum transfers."
    },
    {
        "anchor": "Effects of dynamical quarks on the spectrum of the Wilson Dirac operator: Effects of dynamical quarks on the microscopic spectrum of the Wilson Dirac\noperator are analyzed by means of effective field theory. We consider the\ndistributions of the real modes of the Wilson Dirac operator as well as the\nspectrum of the Hermitian Wilson Dirac operator, and work out the case of one\nflavor in all detail. In contrast to the quenched case, the theory has a mild\nsign problem that manifests itself by giving a spectral density that is not\npositive definite as the spectral gap closes.",
        "positive": "The role of the Polyakov loop in the Dirac operator of QCD at finite\n  temperature: We show how all the contributions to the determinant of the\nDirac-Kogut-Susskind operator of QCD at finite temperature containing a net\nnumber of Polyakov loops become irrelevant in the infinite volume limit. We\ndiscuss also on two of the most interesting physical implications of this\nresult: i) the restoration of the Polyakov symmetry in the full theory with\ndynamical fermions and ii) the total suppression of baryonic thermal\nfluctuations in QCD at finite temperature."
    },
    {
        "anchor": "Charmed hadron physics in quenched anisotropic lattice QCD: We investigate the anisotropic lattice with $O(a)$ improved quark action as a\ncandidate of framework in which we can treat both the heavy and light quark\nregion in the same manner and systematically reduce the systematic\nuncertainties. To examine applicability of anisotropic lattice, we calculate\nthe charmed meson spectrum and decay constants in quenched approximation. We\nfind consistent result with most advanced results on isotropic lattices.",
        "positive": "Recent developments in the tmLQCD software suite: We present an overview of recent developments in the tmLQCD software suite.\nWe summarise the features of the code, including actions and operators\nimplemented. In particular, we discuss the optimisation efforts for modern\narchitectures using the Blue Gene/Q system as an example."
    },
    {
        "anchor": "Infrared fixed point of SU(2) gauge theory with six flavors: We compute the running of the coupling in SU(2) gauge theory with six\nfermions in fundamental representation of the gauge group. We establish an\ninfrared stable fixed point at strong coupling and measure also the anomalous\ndimension of the fermion mass operator at the fixed point. This theory\ntherefore likely lies close to the boundary of the conformal window and will\ndisplay novel infrared dynamics if coupled with the electroweak sector of the\nStandard Model.",
        "positive": "The large-$N$ limit of the chiral condensate from twisted reduced models: We compute the large-$N$ limit of the QCD chiral condensate on the lattice\nusing twisted reduced models, and performing controlled continuum and chiral\nextrapolations. We perform two different calculations: one consists in\nextracting the chiral condensate from the quark mass dependence of the pion\nmass, and the other consists in extracting the chiral condensate from the\nbehaviour of the mode number of the Wilson-Dirac operator for small\neigenvalues. We find consistency between the results of the two methods, giving\na joint estimate of $\\lim_{N\\to\\infty}\\Sigma(N)/N=[184(13)$ MeV$]^3$\n($\\overline{\\mathrm{MS}}$, $\\mu=2$ GeV, taking the square root of the string\ntension $\\sqrt{\\sigma}=440$ MeV to set the scale), in remarkable agreement with\nthe $\\mathrm{SU}(3)$ 2-flavor FLAG result."
    },
    {
        "anchor": "Progress on four flavor QCD with the HISQ action: We describe recent progress on generation of gauge configurations using the\nHighly Improved Staggered Quark (HISQ) action that was designed by the\nHPQCD/UKQCD collaboration. The HISQ action requires two levels of smearing with\na reunitarization of the links before the second smearing. We describe how we\ndeal with the occurrence of occasional large forces arising from the\nreunitarization step. The MILC collaboration is currently generating ensembles\nwith approximate lattice spacings of 0.15, 0.12, 0.09, and 0.06 fm, with the\nstrange and charm quark masses close to their physical values and the mass of\nthe light quarks m_l set to 0.2 m_s. We present recent results for pion taste\nsplittings, light hadron masses, the static potential, the eta_c dispersion\nrelation and the topological susceptibility.",
        "positive": "Beyond complex Langevin equations I: two simple examples: By introducing a second complex variable, the integral relation between a\ncomplex density and the corresponding positive distribution is derived.\nTogether with the positivity and normalizability conditions, this sum rule\nallows to construct explicitly equivalent pairs of distributions in simple\ncases discussed here. In particular the well known solution for a complex\ngaussian distribution is generalized to an arbitrary complex inverse dispersion\nparameter. This opens a possibility of positive representation of Feynman path\nintegrals directly in the Minkowski time."
    },
    {
        "anchor": "Recent progress in staggered chiral perturbation theory: We present a review on recent progress in staggered chiral perturbation\ntheory (SChPT). In the last decade, the scope of the application of SChPT has\nbeen extended beyond the level of calibration into the region of prediction\nwith high precision. SChPT becomes an essential tool to do the data analysis\nreliably for physical observables calculated using improved staggered fermions.\nHere, we focus on the following examples: pion spectrum, pion decay constants,\n$\\varepsilon_K$, and $\\pi-\\pi$ scattering amplitudes. In each subject, we\nreview the recent progress and future prospects.",
        "positive": "SU(3) surface tension from the lattice with the fixed point action: The surface tension at the deconfinement transition of SU(3) is determined\nwith a parametrized version of the fixed point action of a renormalization\ngroup transformation on lattices with temporal extent $N_\\tau=3$ and 4 and\nspatial extent $N_\\sigma/N_\\tau=3$ and 4. A considerable cut-off dependence can\nbe seen in comparison with earlier determinations from tree level Symanzik and\ntadpole improved actions."
    },
    {
        "anchor": "Probes of nearly conformal behavior in lattice simulations of minimal\n  walking technicolor: We present results from high precision, large volume simulations of the\nlattice gauge theory corresponding to minimal walking technicolor. We find\nevidence that the pion decay constant vanishes in the infinite volume limit and\nthat the dependence of the chiral condensate on quark mass m_q is inconsistent\nwith spontaneous symmetry breaking. These findings are consistent with the\nall-orders beta function prediction as well as the Schroedinger functional\nstudies that indicate the existence of a nontrivial infrared fixed point.",
        "positive": "Twenty-first Century Lattice Gauge Theory: Results from the QCD\n  Lagrangian: Quantum chromodynamics (QCD) reduces the strong interactions, in all their\nvariety, to a simple nonabelian gauge theory. It clearly and elegantly explains\nhadrons at short distances, which has led to its universal acceptance. Since\nits advent, however, many of its long-distance, emergent properties have been\nbelieved to be true, without having been demonstrated to be true. This paper\nreviews a variety of results in this regime that have been established with\nlattice gauge theory, directly from the QCD Lagrangian. This body of work sheds\nlight on the origin of hadron masses, its interplay with dynamical symmetry\nbreaking, as well as on other intriguing features such as the phase structure\nof QCD. In addition, nonperturbative QCD is quantitatively important to many\naspects of particle physics (especially the quark flavor sector), nuclear\nphysics, and astrophysics. This review also surveys some of the most\ninteresting connections to those subjects."
    },
    {
        "anchor": "Renormalization of domain-wall bilinear operators with short-distance\n  current correlators: We determine the renormalization constants for flavor non-singlet fermion\nbilinear operators of M\\\"obius domain-wall fermions. The renormalization\ncondition is imposed on the correlation functions in the coordinate space, such\nthat the non-perturbative lattice calculation reproduces the perturbatively\ncalculated counterpart at short distances. The perturbative expansion is\nprecise as the coefficients are available up to $O(\\alpha_s^4)$. We employ\n$2+1$-flavor lattice ensembles at three lattice spacings in the range\n0.044--0.080~fm.",
        "positive": "Theory of color confinement: state of the art: The existing evidence for dual superconductivity as mechanism of color\nconfinement is reviewed. We also discuss what is known on the dual excitations,\nwhich produce confinement by condensation, and what are the open problems"
    },
    {
        "anchor": "Uncovering Low-Dimensional Topological Structure in the QCD Vacuum: Recently, we have pointed out that sign-coherent 4-dimensional structures can\nnot dominate topological charge fluctuations in QCD vacuum at all scales. Here\nwe show that an enhanced lower-dimensional coherence is possible. In pure SU(3)\nlattice gauge theory we find that in a typical equilibrium configuration about\n80% of space-time points are covered by two oppositely-charged connected\nstructures built of elementary 3-dimensional coherent hypercubes. The\nhypercubes within the structure are connected through 2-dimensional common\nfaces. We suggest that this coherence is a manifestation of a low-dimensional\norder present in the QCD vacuum. The use of a topological charge density\nassociated with Ginsparg-Wilson fermions (\"chiral smoothing\") is crucial for\nobserving this structure.",
        "positive": "Analysis and Development of Stochastic Multigrid Methods in Lattice\n  Field Theory: We study the relation between the dynamical critical behavior and the\nkinematics of stochastic multigrid algorithms. The scale dependence of\nacceptance rates for nonlocal Metropolis updates is analyzed with the help of\nan approximation formula. A quantitative study of the kinematics of multigrid\nalgorithms in several interacting models is performed. We find that for a\ncritical model with Hamiltonian H(phi) absence of critical slowing down can\nonly be expected if the expansion of <H(phi+psi)> in terms of the shift psi\ncontains no relevant term (mass term). The predictions of this rule are\nverified in a multigrid Monte Carlo simulation of the Sine Gordon model in two\ndimensions. Our analysis can serve as a guideline for the development of new\nalgorithms: We propose a new multigrid method for nonabelian lattice gauge\ntheory, the time slice blocking. For SU(2) gauge fields in two dimensions,\ncritical slowing down is almost completely eliminated by this method, in\naccordance with the theoretical prediction. The generalization of the time\nslice blocking to SU(2) in four dimensions is investigated analytically and by\nnumerical simulations. Compared to two dimensions, the local disorder in the\nfour dimensional gauge field leads to kinematical problems."
    },
    {
        "anchor": "One-loop renormalization of staple-shaped operators in continuum and\n  lattice regularizations: In this paper we present one-loop results for the renormalization of nonlocal\nquark bilinear operators, containing a staple-shaped Wilson line, in both\ncontinuum and lattice regularizations. The continuum calculations were\nperformed in dimensional regularization, and the lattice calculations for the\nWilson/clover fermion action and for a variety of Symanzik-improved gauge\nactions. We extract the strength of the one-loop linear and logarithmic\ndivergences (including cusp divergences), which appear in such nonlocal\noperators; we identify the mixing pairs which occur among some of these\noperators on the lattice, and we calculate the corresponding mixing\ncoefficients. We also provide the appropriate RI'-like scheme, which\ndisentangles this mixing nonperturbatively from lattice simulation data, as\nwell as the one-loop expressions of the conversion factors, which turn the\nlattice data to the MS-bar scheme. Our results can be immediately used for\nimproving recent nonperturbative investigations of transverse\nmomentum-dependent distribution functions (TMDs) on the lattice. Finally,\nextending our perturbative study to general Wilson-line lattice operators with\nn cusps, we present results for their renormalization factors, including\nidentification of mixing and determination of the corresponding mixing\ncoefficients, based on our results for the staple operators.",
        "positive": "The deconfinement transition of finite density QCD with heavy quarks\n  from strong coupling series: Starting from Wilson's action, we calculate strong coupling series for the\nPolyakov loop susceptibility in lattice gauge theories for various small N_\\tau\nin the thermodynamic limit. Analysing the series with Pad\\'e approximants, we\nestimate critical couplings and exponents for the deconfinement phase\ntransition. For SU(2) pure gauge theory our results agree with those from\nMonte-Carlo simulations within errors, which for the coarser N_\\tau=1,2\nlattices are at the percent level. For QCD we include dynamical fermions via a\nhopping parameter expansion. On a N_\\tau=1 lattice with N_f=1,2,3, we locate\nthe second order critical point where the deconfinement transition turns into a\ncrossover. We furthermore determine the behaviour of the critical parameters\nwith finite chemical potential and find the first order region to shrink with\ngrowing \\mu. Our series moreover correctly reflects the known Z(N) transition\nat imaginary chemical potential."
    },
    {
        "anchor": "Anomalous Fermion Number Non-Conservation on the Lattice: The anomaly for the fermion number current is calculated on the lattice in a\nsimple prototype model with an even number of fermion doublets.",
        "positive": "A Lattice Chiral Gauge Theory with Multifermion Couplings: Analyzing an $SU_L(2)$-chiral gauge theory with external multifermion\ncouplings, we find a possible scaling region where doublers decouple by\nacquiring chiral-invariant masses and $\\psi_R$ is free mode owing to the\n$\\psi_R$-shift-symmetry, the chiral continuum theory of $\\psi^i_L$ can be\ndefined. This is not in agreement with the general belief of the failure of\ntheories so constructed ."
    },
    {
        "anchor": "Do Instantons of the CP(N-1) Model Melt?: In the two-dimensional CP(N-1) model one can parametrize exact many-instanton\nsolutions via N `constituents' (called `zindons'). This parameterization\nallows, in principle, a complete `melting' of individual instantons. The model\nis therefore well suited to study whether dynamics prefers a dilute or a\nstrongly overlapping ensemble of instantons. We study the statistical mechanics\nof instantons both analytically and numerically. We find that at N=2 the\ninstanton system collapses into zero-size instantons. At N=3,4 we find that\nwell-isolated instantons are dynamically preferred though 15-25% of instantons\nhave a considerable overlap with others.",
        "positive": "Probing for the Trace Estimation of a Permuted Matrix Inverse\n  Corresponding to a Lattice Displacement: In this work, we study probing for the more general problem of computing the\ntrace of a permutation of $A^{-1}$, say $PA^{-1}$. The motivation comes from\nLattice QCD where we need to construct \"disconnected diagrams\" to extract\nflavor-separated Generalized Parton functions. In Lattice QCD, where the matrix\nhas a 4D toroidal lattice structure, these non-local operators correspond to a\n$PA^{-1}$ where $P$ is the permutation relating to some displacement $\\vec{p}$\nin one or more dimensions. We focus on a single dimension displacement ($p$)\nbut our methods are general. We show that probing on $A^k$ or $(PA)^k$ do not\nannihilate the largest magnitude elements. To resolve this issue, our\ndisplacement-based probing works on $PA^k$ using a new coloring scheme that\nworks directly on appropriately displaced neighborhoods on the lattice. We\nprove lower bounds on the number of colors needed, and study the effect of this\nscheme on variance reduction, both theoretically and experimentally on a\nreal-world Lattice QCD calculation. We achieve orders of magnitude speedup over\nthe unprobed or the naively probed methods."
    },
    {
        "anchor": "The two-phase issue in the O(n) non-linear $\u03c3$-model: A Monte Carlo\n  study: We have performed a high statistics Monte Carlo simulation to investigate\nwhether the two-dimensional O(n) non-linear sigma models are asymptotically\nfree or they show a Kosterlitz- Thouless-like phase transition. We have\ncalculated the mass gap and the magnetic susceptibility in the O(8) model with\nstandard action and the O(3) model with Symanzik action. Our results for O(8)\nsupport the asymptotic freedom scenario.",
        "positive": "The $B_{s}\\to \u03bc^{+}\u03bc^{-}\u03b3$ decay rate at large $q^{2}$ from\n  lattice QCD: We determine, by means of lattice QCD calculations, the local form factors\ndescribing the $B_{s}\\to \\mu^{+}\\mu^{-}\\gamma$ decay. For this analysis we make\nuse of the gauge configurations produced by the ETM Collaboration with\n$N_{f}=2+1+1$ flavour of Wilson-Clover twisted-mass fermions at maximal twist.\nTo obtain the $B_{s}$ meson form-factors, we perform simulations for several\nheavy-strange meson masses $m_{H_{s}}$ in the range $m_{H_{s}} \\in [ m_{D_{s}},\n2 m_{D_{s}} ]$, and extrapolate to the physical $B_{s}$ meson point\n$m_{B_{s}}\\simeq 5.367~{\\rm GeV}$ making use of the HQET scaling laws. We cover\nthe region of large di-muon invariant masses $\\sqrt{q^{2}} > 4.16\\,{\\rm GeV}$,\nand use our results to determine the branching fraction for $B_{s}\\to\n\\mu^{+}\\mu^{-}\\gamma$, which has been recently measured by LHCb in the region\n$\\sqrt{q^{2}} > 4.9\\,{\\rm GeV}$. The largest contribution to the uncertainty in\nthe partial branching fractions at values of $\\sqrt{q^{2}} < 4.8\\,{\\rm GeV}$ is\nnow due to resonance and other long-distance effects, including those from\n\"charming penguins\", which we estimate by summing over the contributions from\nthe $J_P=1^-$ charmonium resonances."
    },
    {
        "anchor": "Modified Block BiCGSTAB for Lattice QCD: We present results for application of block BiCGSTAB algorithm modified by\nthe QR decomposition and the SAP preconditioner to the Wilson-Dirac equation\nwith multiple right-hand sides in lattice QCD on a $32^3 \\times 64$ lattice at\nalmost physical quark masses. The QR decomposition improves convergence\nbehaviors in the block BiCGSTAB algorithm suppressing deviation between true\nresidual and recursive one. The SAP preconditioner applied to the\ndomain-decomposed lattice helps us minimize communication overhead. We find\nremarkable cost reduction thanks to cache tuning and reduction of number of\niterations.",
        "positive": "Light meson form factors at high $Q^2$ from lattice QCD: Measurements and theoretical calculations of meson form factors are essential\nfor our understanding of internal hadron structure and QCD, the dynamics that\nbind the quarks in hadrons. The pion electromagnetic form factor has been\nmeasured at small space-like momentum transfer $|q^2| < 0.3$~GeV$^2$ by pion\nscattering from atomic electrons and at values up to $2.5$~GeV$^2$ by\nscattering electrons from the pion cloud around a proton. On the other hand, in\nthe limit of very large (or infinite) $Q^2=-q^2$, perturbation theory is\napplicable. This leaves a gap in the intermediate $Q^2$ where the form factors\nare not known.\n  As a part of their 12 GeV upgrade Jefferson Lab will measure pion and kaon\nform factors in this intermediate region, up to $Q^2$ of $6$~GeV$^2$. This is\nthen an ideal opportunity for lattice QCD to make an accurate prediction ahead\nof the experimental results. Lattice QCD provides a from-first-principles\napproach to calculate form factors, and the challenge here is to control the\nstatistical and systematic uncertainties as errors grow when going to higher\n$Q^2$ values.\n  Here we report on a calculation that tests the method using an $\\eta_s$\nmeson, a 'heavy pion' made of strange quarks, and also present preliminary\nresults for kaon and pion form factors. We use the $n_f=2+1+1$ ensembles made\nby the MILC collaboration and Highly Improved Staggered Quarks, which allows us\nto obtain high statistics. The HISQ action is also designed to have small\ndiscretisation errors. Using several light quark masses and lattice spacings\nallows us to control the chiral and continuum extrapolation and keep systematic\nerrors in check."
    },
    {
        "anchor": "Lattice measurement of \u03b1_s with a realistic charm quark: We report on an estimate of \\alpha_s, renormalised in the MSbar scheme at the\ntau and Z^0 mass scales, by means of lattice QCD. Our major improvement\ncompared to previous lattice calculations is that, for the first time, no\nperturbative treatment at the charm threshold has been required since we have\nused statistical samples of gluon fields built by incorporating the vacuum\npolarisation effects of u/d, s and c sea quarks. Extracting \\alpha_s in the\nTaylor scheme from the lattice measurement of the ghost-ghost-gluon vertex, we\nobtain \\alpha_s^{MSbar}(m^2_Z)=0.1200(14) and\n\\alpha_s^{MSbar}(m^2_tau)=0.339(13).",
        "positive": "Computational Strategies in Lattice QCD: Lectures given at the Summer School on \"Modern perspectives in lattice QCD\",\nLes Houches, August 3-28, 2009"
    },
    {
        "anchor": "$B_s \\to K\\ell\u03bd$ form factors from lattice QCD with domain-wall heavy\n  quarks: We report on our on-going study of the $B_s \\to K\\ell\\nu$ decay in $N_f=2+1$\nlattice QCD. We employ fully relativistic setup in which the M\\\"obius\ndomain-wall action is used for all quark flavors. The lattice cutoff is $a^{-1}\n\\sim 2.5$ GeV, where we take bottom quark masses up to $m_Q\\!<\\!0.7a^{-1}$ in\norder to control discretization errors. We present preliminary results for the\nrelevant form factors extracted from correlator ratios by inspecting their\nground state saturation.",
        "positive": "Perturbative renormalization of GPDs to O(a^2), for various\n  fermion/gluon actions: We present a 1-loop perturbative calculation of the fermion propagator, up to\nO(a^2) (a: lattice spacing). The fermions are described by Wilson, clover and\ntwisted-mass actions; for gluons we use Symanzik improved actions (Plaquette,\nTree-level Symanzik, Iwasaki, TILW, DBW2). Our results are given in a general\ncovariant gauge, and their dependence on the coupling constant, the external\nmomentum, the masses and the clover parameter is shown explicitly. We also\nstudy the O(a^2) corrections to matrix elements of unpolarized/polarized\nfermion bilinear operators, which include up to one derivative. These\ncorrections are essential ingredients for improving, to O(a^2), the\nrenormalization constants of the operators under study. In addition, they can\nbe used to minimize lattice artifacts in non-perturbative studies."
    },
    {
        "anchor": "Continuum Behaviour of Lattice QED, Discretized with One-Sided Lattice\n  Differences, in One-Loop Order: A lattice action for QED is considered, where the derivatives in the Dirac\noperator are replaced by one-sided lattice differences. A systematic expansion\nin the lattice spacing of the one-loop contribution to the fermion self energy,\nvacuum polarization tensor and vertex function is carried out for an arbitrary\nchoice of one-sided lattice differences. It is shown that only the vacuum\npolarization tensor possesses the correct continuum limit, while the fermion\nself energy and vertex function receive non-covariant contributions. A lattice\naction, discretized with a fixed choice of one-sided lattice differences\ntherefore does not define a renormalizable field theory. The non-covariant\ncontributions can however be eliminated by averaging the expressions over all\npossible choices of one-sided lattice differences.",
        "positive": "Hadronic light-by-light scattering contribution to the muon g-2 on the\n  lattice: We briefly review several activities at Mainz related to hadronic\nlight-by-light scattering (HLbL) using lattice QCD. First we present a\nposition-space approach to the HLbL contribution in the muon g-2, where we\nfocus on exploratory studies of the pion-pole contribution in a simple model\nand the lepton loop in QED in the continuum and in infinite volume. The second\npart describes a lattice calculation of the double-virtual pion transition form\nfactor F_{pi^0 gamma^* gamma^*}(q_1^2, q_2^2) in the spacelike region with\nphoton virtualities up to 1.5 GeV^2 which paves the way for a lattice\ncalculation of the pion-pole contribution to HLbL. The third topic involves\nHLbL forward scattering amplitudes calculated in lattice QCD which can be\ndescribed, using dispersion relations (HLbL sum rules), by gamma^* gamma^* ->\nhadrons fusion cross sections and then compared with phenomenological models."
    },
    {
        "anchor": "Nonperturbative ``Lattice Perturbation Theory'': We discuss a program for replacing standard perturbative methods with Monte\nCarlo simulations in short distance lattice gauge theory calculations.",
        "positive": "Predicting the Aoki Phase using the Chiral Lagrangian: This work is concerned with the phase diagram of Wilson fermions in the mass\nand coupling constant plane for two-flavor (unquenched) QCD. We show that as\nthe continuum limit is approached, one can study the lattice theory using the\ncontinuum chiral Lagrangian, supplemented by additional terms proportional to\npowers of the lattice spacing. We find two possible phase structures at\nnon-zero lattice spacing: (1) There is an Aoki phase of spontaneously broken\nflavor and parity, with two massless Goldstone-pions, and a width $\\Delta m_0\n\\sim a^3$; (2) There is no spontaneous symmetry breaking, and all three pions\nhave equal mass of order $a$. Present numerical simulations suggest that the\nformer option is realized."
    },
    {
        "anchor": "Large $N$ scaling and factorization in $\\mathrm{SU}(N)$ Yang-Mills\n  theory: We present results for Wilson loops smoothed with the Yang-Mills gradient\nflow and matched through the scale $t_0$. They provide renormalized and precise\noperators allowing to test the $1/N^2$ scaling both at finite lattice spacing\nand in the continuum limit. Our results show an excellent scaling up to $1/N =\n1/3$. Additionally, we obtain a very precise non-perturbative confirmation of\nfactorization in the large $N$ limit.",
        "positive": "Perturbative calculation of the clover term for Wilson fermions in any\n  representation of the gauge group SU(N): We calculate the Sheikholeslami-Wohlert coefficient of the O(a) improvement\nterm for Wilson fermions in any representation of the gauge group SU(N)\nperturbatively at the one-loop level. The result applies to QCD with adjoint\nquarks and to N=1 supersymmetric Yang-Mills theory on the lattice."
    },
    {
        "anchor": "Another look at the Landau-gauge gluon and ghost propagators at low\n  momentum: We study the gluon and ghost propagators of SU(2) lattice Landau gauge theory\nand find their low-momentum behavior being sensitive to the lowest non-trivial\neigenvalue (\\lambda_1) of the Faddeev-Popov operator. If the gauge-fixing\nfavors Gribov copies with small (large) values for \\lambda_1 both the ghost\ndressing function and the gluon propagator get enhanced (suppressed) at low\nmomentum. For larger momenta no dependence on Gribov copies is seen. We compare\nour lattice data to the corresponding (decoupling) solutions from the DSE/FRGE\nstudy of Fischer, Maas and Pawlowski [Annals Phys. 324 (2009) 2408] and find\nqualitatively good agreement.",
        "positive": "The gradient flow in simple field theories: The gradient flow is a valuable tool for the lattice community, with\napplications from scale-setting to implementing chiral fermions. Here I focus\non the gradient flow as a means to suppress power-divergent mixing.\nPower-divergent mixing stems from the hypercubic symmetry of the lattice\nregulator and is a particular difficulty for calculations of, for example, high\nmoments of parton distribution functions. The gradient flow removes\npower-divergent mixing on the lattice, provided the flow time is kept fixed in\nphysical units, at the expense of introducing a new physical scale in the\ncontinuum. One approach to dealing with this new scale is the smeared operator\nproduct expansion, a formalism that systematically connects nonperturbative\ncalculations of flowed operators to continuum physics. I study the role of the\ngradient flow in suppressing power-divergent mixing and present the first\nnonperturbative study in scalar field theory."
    },
    {
        "anchor": "The shape of the D -> K semileptonic form factor from full lattice QCD\n  and V_cs: We present a new study of the form factors for D -> K semileptonic decay from\nlattice QCD that allows us to compare the shape of the vector form factor to\nexperiment and, for the first time, to extract V_cs using results from all\nexperimental q^2 bins. The valence quarks are implemented with the Highly\nImproved Staggered Quark action on MILC configurations that include u, d and s\nsea quarks. The scalar and vector currents are nonperturbatively normalised\nand, using phased boundary conditions, we are able to cover the full q^2 range\naccessible to experiment. Our result is V_cs = 0.963(5)_{expt}(14)_{lattice}.\nWe also demonstrate that the form factors are insensitive to whether the\nspectator quark is u/d or s, which has implications for other decay channels.",
        "positive": "Simulating twisted mass fermions at physical light, strange and charm\n  quark masses: We present the QCD simulation of the first gauge ensemble of two degenerate\nlight quarks, a strange and a charm quark with all quark masses tuned to their\nphysical values within the twisted mass fermion formulation. Results for the\npseudoscalar masses and decay constants confirm that the produced ensemble is\nindeed at the physical parameters of the theory. This conclusion is\ncorroborated by a complementary analysis in the baryon sector. We examine\ncutoff and isospin breaking effects and demonstrate that they are suppressed\nthrough the presence of a clover term in the action."
    },
    {
        "anchor": "Non-Abelian dual Meissner effect and confinement/deconfinement phase\n  transition in SU(3) Yang-Mills theory: The dual superconductivity is a promising mechanism for quark confinement. We\nproposed the non-Abelian dual superconductivity picture for SU(3) Yang-Mills\ntheory, and demonstrated the restricted field dominance (called conventionally\n\"Abelian\" dominance), and non-Abelian magnetic monopole dominance in the string\ntension. In the last conference, we have demonstrated by measuring the\nchromoelectric flux that the non-Abelian dual Meissner effect exists and\ndetermined that the dual superconductivity for SU(3) case is of type I, which\nis in sharp contrast to the SU(2) case: the border of type I and type II.\n  In this talk, we focus on the confinement/deconfinemen phase transition and\nthe non-Abelian dual superconductivity at finite temperature: We measure the\nchromoelectric flux between a pair of static quark and antiquark at finite\ntemperature, and investigate its relevance to the phase transition and the\nnon-Abelian dual Meissner effect.",
        "positive": "Quarkonium Decay Matrix Elements from Quenched Lattice QCD: We calculate the long-distance matrix elements for the decays of the\nlowest-lying S- and P-wave states of charmonium and bottomonium in quenched\nlattice QCD, using a nonrelativistic formulation for the heavy quarks. (The\nshort-distance coefficients are known from perturbation theory.) In particular,\nwe present the first calculation from QCD first principles of the color-octet\ncontribution to P-wave decay---a contribution that is absent in potential\nmodels. We also give the relations between the lattice matrix elements and\ntheir continuum counterparts through one-loop order in perturbation theory."
    },
    {
        "anchor": "Solving the Complex Phase Problem in a QCD Related Model: We discuss an effective theory for QCD at finite chemical potential and\nnon-zero temperature, where QCD is reduced to its center degrees of freedom.\nThe effective action can be mapped to a flux representation, where the complex\nphase problem is solved and the theory accessible to Monte Carlo techniques. In\nthis work, we use a generalized Prokof'ev-Svistunov worm algorithm to perform\nthe simulations and determine the phase diagram as a function of temperature,\nquark mass and chemical potential. It turns out that the transition is\nqualitatively as expected for QCD.",
        "positive": "Mass Spectrum of the 3d SU(2) Higgs Model and the Symmetric Electroweak\n  Phase: We present results for the masses of the low-lying states with quantum\nnumbers $0^{++}$, $2^{++}$ and $1^{--}$ as well as Polyakov line correlations\nin the Higgs and confinement regions of the 3d SU(2) Higgs model. In the\nconfinement phase we find a dense spectrum of bound states approximately split\ninto two disjoint sectors. One consists of W-balls nearly identical to the\nglueball spectrum of the pure gauge theory, the other of bound states of\nscalars."
    },
    {
        "anchor": "Ginsparg-Wilson Relation and Ultralocality: It is shown that it is impossible to construct a free theory of fermions on\ninfinite hypercubic Euclidean lattice in four dimensions that is: (a)\nultralocal, (b) respects symmetries of hypercubic lattice, (c) corresponding\nkernel satisfies D gamma5 + gamma5 D = D gamma5 D (Ginsparg-Wilson relation),\n(d) describes single species of massless Dirac fermions in the continuum limit.",
        "positive": "Thin and dressed Polyakov loops from spectral sums of lattice\n  differential operators: We represent thin and dressed Polyakov loops as spectral sums of eigenvalues\nof differential operators on the lattice. For that purpose we calculate\ncomplete sets of eigenvalues of the staggered Dirac and the covariant Laplace\noperator for several temporal boundary conditions. The spectra from different\nboundary conditions can be combined such that they represent single (thin)\nPolyakov loops, or a collection of loops (dressed Polyakov loops). We analyze\nthe role of the eigenvalues in the spectral sums below and above the critical\ntemperature."
    },
    {
        "anchor": "The Scaling of QED in a Non-Commutative Space-Time: We present results of numerical simulations for pure U(1) gauge theory in a\nnon-commutative space. The theory is mapped onto a dimensionally reduced matrix\nmodel, which renders its numerical treatment feasible. New data on large\nlattices reveal the scaling of Wilson loops and their correlation functions in\nthe simultaneous limit to the continuum and to infinite volume, at fixed\nnon-commutativity. In this on-going project we are particularly interested in\nthe IR behaviour, the ``photo-ball'' spectrum and in the photon dispersion\nrelation.",
        "positive": "Taming the Signal-to-Noise Problem in Lattice QCD by Phase Reweighting: Path integrals describing quantum many-body systems can be calculated with\nMonte Carlo sampling techniques, but average quantities are often subject to\nsignal-to-noise ratios that degrade exponentially with time. A\nphase-reweighting technique inspired by recent observations of random walk\nstatistics in correlation functions is proposed that allows energy levels to be\nextracted from late-time correlation functions with time-independent\nsignal-to-noise ratios. Phase reweighting effectively includes dynamical\nrefinement of source magnitudes but introduces a bias associated with the\nphase. This bias can be removed by performing an extrapolation, but at the\nexpense of re-introducing a signal-to-noise problem. Lattice Quantum\nChromodynamics calculations of the $\\rho$ and nucleon masses and of the\n$\\Xi\\Xi$ binding energy show consistency between standard results obtained\nusing earlier-time correlation functions and phase-reweighted results using\nlate-time correlation functions inaccessible to standard statistical analysis\nmethods."
    },
    {
        "anchor": "Monopoles in QCD: Based on the dual Higgs picture for confinement, we study monopole properties\nin the maximally abelian (MA) gauge using the lattice QCD. The monopole carries\na large fluctuation of the gluon field and provides a large abelian action in\nabelian projected QCD (AP-QCD). We find large cancellation between abelian part\nand off-diagonal part of the action density around the monopole, which ensures\nthe appearance of monopoles. The monopole in the MA gauge can be regarded as\nthe collective mode of the large gluon fluctuation concentrated into the\nabelian sector, and would be relevant degrees of freedom for confinement in\nAP-QCD.",
        "positive": "A simulation of the Schwinger model in the overlap formalism: In the continuum, the single flavor massless Schwinger model has an exact\nglobal axial $U(1)$ symmetry in the sector of perturbative gauge fields. This\nsymmetry is explicitly broken by gauge fields with nonzero topological charge\ninducing a nonzero expectation value for the bilinear $\\bar\\psi\\psi$. We show\nthat a lattice formulation of this model, using the overlap formalism to treat\nthe massless fermions, explicitly exhibits this phenomenon. A Monte Carlo\nsimulation of the complete system yields the correct value of the fermion\ncondensate and shows unambiguously that it originates from the sector of\ntopological charge equal to unity."
    },
    {
        "anchor": "A Microscopic study of Magnetic monopoles in Topological Insulators: In this article, we analyze a magnetic monopole in topological insulators.\nThe monopole obtain a fractional electric charge because of the Witten effect.\nWe consider this system with a microscopic view by adding the Wilson term to\nthe ordinary Dirac Hamiltonian. The Wilson term yields the positive mass shift\nto the effective mass of the electrons, then the curved domain-wall is\ndynamically generated around the monopole. The zero-modes of the electrons are\nlocalized on the domain-wall, which can be identified as the source of the\nelectric charge.",
        "positive": "The Deuteron and Exotic Two-Body Bound States from Lattice QCD: Results of a high-statistics, multi-volume Lattice QCD exploration of the\ndeuteron, the di-neutron, the H-dibaryon, and the Xi-Xi- system at a pion mass\nof m ~ 390 MeV are presented. Calculations were performed with an anisotropic\nn_f = 2+1 Clover discretization in four lattice volumes of spatial extent L ~\n2.0, 2.5, 3.0 and 4.0 fm, with a lattice spacing of b_s ~ 0.123 fm in the\nspatial-direction, and b_t ~ b_s/3.5 in the time-direction. The Xi-Xi- is found\nto be bound by B_{Xi-Xi-} = 14.0(1.4)(6.7) MeV, consistent with expectations\nbased upon phenomenological models and low-energy effective field theories\nconstrained by nucleon-nucleon and hyperon-nucleon scattering data at the\nphysical light-quark masses. We find weak evidence that both the deuteron and\nthe di-neutron are bound at this pion mass, with binding energies of B_d =\n11(05)(12) MeV and B_{nn} = 7.1(5.2)(7.3) MeV, respectively. With an increased\nnumber of measurements and a refined analysis, the binding energy of the\nH-dibaryon is B_H = 13.2(1.8)(4.0) MeV at this pion mass, updating our previous\nresult."
    },
    {
        "anchor": "Toward the Global Structure of Conformal Theories in the SU(3) Gauge\n  Theory: We introduce a new concept \"conformal theories with an IR cutoff\", after\npointing out that the following two categories in SU(3) gauge theories with\nfundamental N_f fermions possess an IR fixed point: Large N_f QCD with N_f in\nthe conformal window (referred as Conformal QCD) and small N_f QCD with N_f out\nof the conformal window at temperature T/Tc > 1 (referred as High Temperature\nQCD).\n  In the conformal theories with an IR cutoff there exists the \"conformal\nregion'\" together with the confining region and the deconfining region. We\nverify numerically on a lattice of the size 16^3 x64 the existence of the\nconformal region and the non-trivial Z(3) structure of the vacuum and the\nYukawa-type decay form of meson propagators in the conformal region.\n  We stress that High Temperature QCD is intrinsically accompanied with an IR\ncutoff. Therefore the understanding the vacuum structure and the property of\ncorrelation functions is the key to resolve long standing issues in High\nTemperature QCD.\n  We further argue that there is a precise correspondence between Conformal QCD\nand High Temperature QCD in the temporal propagators under the change of the\nparameters N_f and T/T_c respectively: the one boundary is close to meson\nstates and the other is close to free quark states.\n  In particular, we find the correspondence between Conformal QCD with N_f = 7\nand High Temperature QCD with N_f=2 at T ~ 2 Tc being in close relation to a\nmeson unparticle model. From this we estimate the anomalous mass dimension\ngamma* = 1.2 (1) for N_f=7.",
        "positive": "QCD thermodynamics at zero and non-zero density: We present recent results on thermodynamics of QCD with almost physical light\nquark masses and a physical strange quark mass value. These calculations have\nbeen performed with an improved staggerd action especially designed for finite\ntemperature lattice QCD. In detail we present a calculation of the transition\ntemperature, using a combined chiral and continuum extrapolation. Furthermore\nwe present preliminary results on the interaction measure and energy density at\nalmost realistic quark masses. Finally we disscuss the response of the pressure\nto a finite quark chemical potential. Within the Taylor expansion formalism we\ncalculate quark number susceptibilities and leading order corrections to finite\nchemical potential. This is particularly usefull for mapping out the critical\nregion in the QCD phase diagram."
    },
    {
        "anchor": "Hadronic Correlators from All-point Quark Propagators: A method for computing all-point quark propagators is applied to a variety of\nprocesses of physical interest in lattice QCD. The method allows, for example,\nefficient calculation of disconnected parts and full momentum-space 2 and 3\npoint functions. Examples discussed include: extraction of chiral Lagrangian\nparameters from current correlators, the pion form factor, and the unquenched\neta-prime.",
        "positive": "Hadronic contribution to the running of the electromagnetic coupling\n  constant from lattice QCD: challenges at short distances: The electromagnetic coupling constant, $\\alpha$, is one of the fundamental\nparameters of the Standard Model (SM). Its value at the Z boson mass,\n$\\alpha(M_Z)$, is of particular interest as it enters electroweak precision\ntests. When running $\\alpha$ from low energies up to the Z mass, five orders of\nmagnitude in precision are lost. This makes it one of the least well determined\nparameters of the SM at that scale. The largest source of error comes from\nnon-perturbative hadronic effects in the low energy region. These\nnon-perturbative effects can be determined from ab-initio calculations in\nlattice QCD. At higher energies, needed to match onto QCD perturbation theory,\ndiscretization errors become large. In addition, the hadronic vacuum\npolarization receives logarithmically-enhanced cutoff effects which render the\ncontinuum extrapolation more difficult. To better control this extrapolation at\nhigher energies, we test a number of improvement procedures based on lattice\nperturbation theory. To illustrate their effect, we present a preliminary\nanalysis of the light quark, connected contribution to the Adler function at\nEuclidean $Q^2=5$ GeV$^2$. The lattice results are obtained using simulations\nwith $2+1+1$ flavors of staggered fermions at physical values of the quark\nmasses."
    },
    {
        "anchor": "Hadron masses: lattice QCD and chiral effective field theory: This work discusses reliability, possible obstacles and the future\nperspective of chiral extrapolation of lattice results. In the first part,\nchiral perturbation theory fits to lattice calculations of the nucleon mass are\nthoroughly explored in terms of statistical uncertainty and convergence.\nLattice volume dependence is exploited as a source of additional fit\nconstraints. In discussing consistency with pion-nucleon scattering, the role\nof the Delta(1232) excitation is clarified. In the second part of the work,\npion and kaon mass lattice data are analyzed using three-flavor chiral\nperturbation theory. SU(3)-SU(2) matching conditions permit to examine\ndeviations from the Gell-Mann, Oakes, Renner relation. Introductory chapters\nprovide a quick start guide to manifestly covariant baryon chiral perturbation\ntheory, basic understanding of lattice QCD and a self-contained explanation of\nthe relevant statistical methods.",
        "positive": "The ground state of three quarks: We measure the static three-quark potential in SU(3) lattice gauge theory\nwith improved accuracy, by using all available technical refinements, including\nLuscher-Weisz exponential variance reduction. Together with insight gained from\n3-state Potts model simulations, our results allow us to sort out the merits of\nthe Delta- and Y-ansaetze."
    },
    {
        "anchor": "Hadronic Screening in Improved Taste: We present our results on meson and nucleon screening masses in finite\ntemperature two flavour QCD using smeared staggered valence quarks and\nstaggered thin-link sea quarks with different lattice spacings and quark\nmasses. We investigate optimization of smearing by observing its effects on the\ninfrared (IR) and ultraviolet (UV) components of gluon and quark fields. The\napplication of smearing to screening at finite temperature also provides a\ntransparent window into the mechanism of the interplay of smearing and chiral\nsymmetry. The improved hadronic operators show that above the finite\ntemperature cross over, T_c, screening masses are consistent with weak-coupling\npredictions. There is also evidence for a rapid opening up of a spectral gap of\nthe Dirac operator immediately above T_c.",
        "positive": "Study of the critical point in lattice QCD at high temperature and\n  density: We propose a method to probe the nature of phase transitions in lattice QCD\nat finite temperature and density, which is based on the investigation of an\neffective potential as a function of the average plaquette. We analyze data\nobtained in a simulation of two-flavor QCD using p4-improved staggered quarks\nwith bare quark mass $m/T = 0.4$, and find that a first order phase transition\nline appears in the high density regime for $\\mu_q/T \\sim 2.5$. The effective\npotential as a function of the quark number density is also studied. We\ncalculate the chemical potential as a function of the density from the\ncanonical partition function and discuss the existence of the first order phase\ntransition line."
    },
    {
        "anchor": "Localization properties of fermions and bosons: The topological structure of the QCD vacuum can be probed by monitoring the\nspatial localization of the low-lying Dirac eigenmodes. This approach can be\npursued on the lattice, and unlike the traditional one requires no smoothing of\nthe gauge field. I review recent lattice studies, attempting to extract a\nconsistent description. What emerges is a picture of the vacuum as a\n``topological sandwich'' of alternating, infinitely thin 3d layers of opposite\ntopological charge, as originally seen in direct measurements of the\ntopological charge density.",
        "positive": "Determination of $c_\\mathrm A$ in three-flavour lattice QCD with Wilson\n  fermions and tree-level improved gauge action: We report on an ongoing non-perturbative determination of the improvement\ncoefficient of the axial current, $c_\\mathrm A$, with three flavours of\ndynamical $\\mathrm O(a)$ improved Wilson quarks and tree-level Symanzik\nimproved gauge action. Our computations are based on simulations with the\nopenQCD code. The improvement condition for a range of couplings is formulated\nwith Schr\\\"odinger functional boundary conditions and imposed along a line of\nconstant physics in parameter space. Our analysis involves correlation\nfunctions with boundary wave functions such that a large sensitivity to\n$c_\\mathrm A$ can be reached by exploiting the PCAC relation with two different\npseudoscalar states."
    },
    {
        "anchor": "Lattice Results for Low Moments of Light Meson Distribution Amplitudes: As part of the UKQCD and RBC collaborations' N_f=2+1 domain-wall fermion\nphenomenology programme, we calculate the first two moments of the light-cone\ndistribution amplitudes of the pseudoscalar mesons pion and kaon and the\n(longitudinally-polarised) vector mesons rho, K-star and phi. We obtain the\ndesired quantities with good precision and are able to discern the expected\nquark-mass dependence of SU(3)-flavour breaking effects. An important\ningredient of the calculation is the nonperturbative renormalisation of lattice\noperators using the RI'/MOM technique.",
        "positive": "Quarkonium correlators at finite temperature and potential models: We discuss the calculations of quarkonium spectral functions in potential\nmodels and their implications for the interpretation of the lattice data on\nquarkonium correlators. In particular, we find that melting of different\nquarkonium states does not lead to significant change in the Euclidean time\ncorrelators. The large change of the quarkonium correlators above deconfinement\nobserved in the scalar and axial-vector channels appears to be due to the zero\nmode contribution."
    },
    {
        "anchor": "B-physics with dynamical domain-wall light quarks and relativistic\n  b-quarks: We report on our progress in calculating the B-meson decay constants and\nB^0-bar B^0 mixing parameters using domain-wall light quarks and relativistic\nb-quarks. We present our computational method and show some preliminary results\nobtained on the coarser (a approx 0.11fm) 24^3 lattices. This work is presented\non behalf of the RBC and UKQCD collaborations.",
        "positive": "Critical Behaviour in Statistical QCD: We survey the critical behaviour of strongly interacting matter, as\ndetermined in finite temperature lattice QCD."
    },
    {
        "anchor": "Composite Higgs Dynamics on the Lattice: We investigate the spectrum of the SU(2) gauge theory with $N_f$ = 2 flavors\nof fermions in the fundamental representation, in the continuum, using lattice\nsimulations. This model provides a minimal template which has been used for\ndifferent strongly coupled extensions of the Standard Model ranging from\ncomposite (Goldstone) Higgs models to intriguing types of dark matter\ncandidates, such as the SIMPs. Here we will focus on the composite Goldstone\nHiggs paradigm, for which this model provides a minimal UV complete realization\nin terms of a new strong sector with fermionic matter. After introducing the\nrelevant Lattice methods used in our simulations, we will discuss our numerical\nresults. We show that this model features a SU(4)/Sp(4) $\\sim$ SO(6)/SO(5)\nflavor symmetry breaking pattern, and estimate the value of its chiral\ncondensate. Finally, we present our results for the mass spectrum of the\nlightest spin one and zero resonances, analogue to the QCD $\\rho$, $a_1$,\n$\\sigma$, $\\eta'$, $a_0$ resonances, which are relevant for searches of new,\nexotic resonances at the LHC.",
        "positive": "On the $N_f$-dependence of gluonic observables: We compute $t_0$, $w_0$ and the topological susceptibility, defined at finite\ngradient flow time for two-flavour QCD. The use of three lattice spacings and\npion masses between 192 and 500 MeV together with a careful error analysis\nallow to approach the continuum limit of the two-flavour theory despite\nsignificant auto-correlations. A comparison to $N_f=0$ results shows the size\nof sea quark effects in $t_0^2\\chi$, with $\\chi$ the topological\nsusceptibility, and low energy observables such as $t_0/w_0^2$ and $t_0/r_0^2$."
    },
    {
        "anchor": "Recent Progress in Lattice Parton-Distribution Calculations: The large-momentum effective theory (LaMET) framework has been widely used to\ndetermine the Bjorken-$x$ dependence of parton distribution functions (PDFs) in\nlattice-QCD hadron-structure calculations. In this proceeding, I highlighted\nselected recent lattice-QCD results on parton distributions from MSULat group.\nWe use clover valence fermions on ensembles generated by MILC Collaboration\nwith lattice spacing $a \\approx 0.06$, 0.09, and 0.12 fm, with $M_\\pi L \\approx\n4$, and with pion masses including 135, 220 and 310 MeV and $N_f=2+1+1$ flavors\nof highly improved staggered dynamical quarks. Results include the\ncontinuum-physical isovector nucleon PDF, a first study of the strange and\ncharm PDFs and the pion and kaon valence-quark PDFs. We also reported results\non the $Q^2$ and $x$ dependence of nucleon isovector unpolarized and helicity\nGPDs calculated directly at physical pion mass; we also make a comparison of\nthe GPDs with the traditional moment methods from other lattice calculations.",
        "positive": "Vortex waistlines and vortex gas: We investigate the manner in which a linear potential arises from\nfluctuations due to vortices linked with the Wilson loop. In particular, the\ncustomary naive picture is critically reexamined."
    },
    {
        "anchor": "Temperature dependence of electrical conductivity and dilepton rates\n  from hot quenched lattice QCD: We present new results on the continuum extrapolation of the vector current\ncorrelation function in the deconfined phase for three temperatures close to\nthe critical temperature utilizing quenched clover improved Wilson fermions and\nlight quark masses. A systematic analysis on multiple lattice spacing allows to\nperform the continuum limit of the correlation function and to extract spectral\nproperties in the continuum limit. These results provide constraints for the\nelectrical conductivity and the thermal dilepton rates in the quark gluon\nplasma for the given temperature range. In addition results on the continuum\nextrapolation at finite momenta related to thermal photon rates are presented.",
        "positive": "fB from finite size effects in lattice QCD: We discuss a novel method to calculate fB on the lattice based on the study\nof the dependence of finite size effects upon the heavy quark mass of flavoured\nmesons and on a non--perturbative recursive finite size technique. This method\navoids the systematic errors related to extrapolations from the static limit or\nto the tuning of the coefficients of effective Lagrangian and the results admit\nan extrapolation to the continuum limit. We show the results of a first\nestimate at finite lattice spacing, but close to the continuum limit, giving fB\n= 170(11)(5)(22)MeV. We also obtain fBs = 192(9)(5)(24)MeV. The first error is\nstatistical, the second is our estimate of the systematic error from the method\nand the third the systematic error from the specific approximations adopted in\nthis first exploratory calculation. The method can be generalized to two--scale\nproblems in lattice QCD."
    },
    {
        "anchor": "Nucleon scalar matrix elements with $N_f=2+1+1$ twisted mass fermions: We investigate scalar matrix elements of the nucleon using $N_f=2+1+1$\nflavors of maximally twisted mass fermions at a fixed value of the lattice\nspacing of $a\\approx 0.078{\\rm fm}$. We compute disconnected contributions to\nthe relevant three-point functions using an efficient noise reduction\ntechnique. Using these methods together with an only multiplicative\nrenormalization applicable for twisted mass fermions, allows us to obtain\naccurate results in the light and strange sector.",
        "positive": "Dynamics of the $O(4)$ critical point in QCD: We perform a real-time simulation of the $O(4)$ critical point of QCD, which\nlies in the dynamic universality class of Model G. The axial charge and the\norder parameter $\\phi_a =(\\sigma, \\vec{\\pi})$ exhibit a rich dynamical\ninterplay, which reflects the qualitative differences in the hydrodynamic\neffective theories above and below $T_c$. From the axial charge correlators on\nthe critical line we extract a dynamical critical exponent of $\\zeta=1.47 \\pm\n0.01 ({\\rm stat})$, which is compatible with the theoretical expectation of\n$\\zeta = d/2$ (with $d=3$) when systematic errors are taken into account. At\nlow temperatures, we quantitatively match the $O(4)$ simulations to the\nsuperfluid effective theory of soft pions."
    },
    {
        "anchor": "Marking up lattice QCD configurations and ensembles: QCDml is an XML-based markup language designed for sharing QCD configurations\nand ensembles world-wide via the International Lattice Data Grid (ILDG). Based\non the latest release, we present key ingredients of the QCDml in order to\nprovide some starting points for colleagues in this community to markup\nvaluable configurations and submit them to the ILDG.",
        "positive": "What happens to the Upsilon and eta_b in the quark-gluon plasma?\n  Bottomonium spectral functions from lattice QCD: We study bottomonium spectral functions in the quark-gluon plasma in the\nUpsilon and eta_b channels, using lattice QCD simulations with two flavours of\nlight quark on highly anisotropic lattices. The bottom quark is treated with\nnonrelativistic QCD (NRQCD). In the temperature range we consider, 0.42 < T/T_c\n< 2.09, we find that the ground states survive, whereas the excited states are\nsuppressed as the temperature is increased. The position and width of the\nground states are compared to analytical effective field theory (EFT)\npredictions. Systematic uncertainties of the maximum entropy method (MEM), used\nto construct the spectral functions, are discussed in some detail."
    },
    {
        "anchor": "Lattice Investigations of Nucleon Structure at Light Quark Masses: Lattice simulations of hadronic structure are now reaching a level where they\nare able to not only complement, but also provide guidance to current and\nforthcoming experimental programmes at, e.g. Jefferson Lab, COMPASS/CERN and\nFAIR/GSI. By considering new simulations at low quark masses and on large\nvolumes, we review the recent progress that has been made in this exciting area\nby the QCDSF/UKQCD collaboration. In particular, results obtained close to the\nphysical point for several quantities, including electromagnetic form factors\nand moments of ordinary parton distribution functions, show some indication of\napproaching their phenomenological values.",
        "positive": "Infrared behavior of the gluon propagator in lattice Landau gauge: the\n  three-dimensional case: We evaluate numerically the three-momentum-space gluon propagator in the\nlattice Landau gauge, for three-dimensional pure-SU(2) lattice gauge theory\nwith periodic boundary conditions. Simulations are done for nine different\nvalues of the coupling $\\beta$, from $\\beta = 0$ (strong coupling) to $\\beta =\n6.0$ (in the scaling region), and for lattice sizes up to $V = 64^3$. In the\nlimit of large lattice volume we observe, in all cases, a gluon propagator\ndecreasing for momenta smaller than a constant value $p_{dec}$. From our data\nwe estimate $p_{dec} \\approx 350$ MeV. The result of a gluon propagator\ndecreasing in the infrared limit has a straightforward interpretation as\nresulting from the proximity of the so-called first Gribov horizon in the\ninfrared directions."
    },
    {
        "anchor": "Hadron spectra from overlap fermions on HISQ gauge configurations: Adopting a mixed action approach, we report here results on hadron spectra\ncontaining one or more charm quarks. We use overlap valence quarks on a\nbackground of 2+1+1 flavor HISQ gauge configurations generated by the MILC\ncollaboration. We also study the ratio of leptonic decay constants, f_Ds*/f_Ds.\nResults are obtained at two lattice spacings.",
        "positive": "Excited hadrons from improved interpolating fields: The calculation of quark propagators for Ginsparg-Wilson-type Dirac operators\nis costly and thus limited to a few different sources. We present a new\napproach for determining spatially optimized operators for lattice spectroscopy\nof excited hadrons. Jacobi smeared quark sources with different widths are\ncombined to construct hadron operators with different spatial wave functions.\nWe study the Roper state and excited rho and pion mesons."
    },
    {
        "anchor": "Towards the continuum limit of the lattice Landau gauge gluon propagator: The infrared behaviour of the lattice Landau gauge gluon propagator is\ndiscussed, combining results from simulations with different volumes and\nlattice spacings. In particular, the Cucchieri-Mendes bounds are computed and\ntheir implications for D(0) discussed.",
        "positive": "Chiral fermion in the Hamiltonian lattice gauge theory: We discuss the chiral fermion in the Hamiltonian formalism of lattice gauge\ntheory. Although the naive chiral charge operator does not commute with the\nHamiltonian, the commutable one can be defined for the overlap fermion. The\neigenvalues of the energy and the chiral charge can be defined simultaneously.\nWe study how the eigenvalue spectrum reflects chiral properties of systems,\nsuch as a chiral chemical potential and the axial anomaly. We also show that\nthe Wilson fermion is a chiral fermion in one dimension."
    },
    {
        "anchor": "Gluon propagator on a centre-vortex background: The impact of $SU(3)$ centre vortices on the gluon propagator in Landau gauge\nis investigated on original, vortex-removed and vortex-only lattice gauge field\nconfigurations. Vortex identification is found to partition the gluon\npropagator into short range strength on the vortex removed configurations and\nlong range strength on the vortex only configurations. The effect of smoothing\nvortex-only configurations is also studied, and a regime for recovering the\nform of the smoothed original propagator from vortex-only configurations is\nintroduced. The results reinforce the significance of centre vortices in a\nfundamental understanding of QCD vacuum structure.",
        "positive": "The running coupling in lattice Landau gauge with unquenched Wilson\n  fermion and KS fermion: The running coupling of the Wilson fermon(JLQCD/CP-PACS) and that of\nKogut-Susskind(KS) fermion(MILC) are measured in the lattice Landau gauge QCD\nin $\\widetilde{MOM}$ scheme. The quark propagator of the KS fermion is also\nmeasured and we find that it is infrared suppressed. The renormalization factor\nof the running coupling and the tadpole renormalization define the scale of the\nquark wave function. Effects of the $A_\\mu^2$ condensates of a few GeV$^2$ are\nobserved in the running coupling and also in the quark propagator."
    },
    {
        "anchor": "First order thermal phase transition with 126 GeV Higgs mass: We study the strength of the electroweak phase transition in models with two\nlight Higgs doublets and a light SU(3)_c triplet by means of lattice\nsimulations in a dimensionally reduced effective theory. In the parameter\nregion considered the transition on the lattice is significantly stronger than\nindicated by a 2-loop perturbative analysis. Within some ultraviolet\nuncertainties, the finding applies to MSSM with a Higgs mass m_h approximately\n126 GeV and shows that the parameter region useful for electroweak baryogenesis\nis enlarged. In particular (even though only dedicated analyses can quantify\nthe issue), the tension between LHC constraints after the 7 TeV and 8 TeV runs\nand frameworks where the electroweak phase transition is driven by light stops,\nseems to be relaxed.",
        "positive": "The low-lying spectrum of N=1 supersymmetric Yang-Mills theory: The spectrum of the lightest bound states in N=1 supersymmetric Yang-Mills\ntheory with SU(2) gauge group, calculated on the lattice, is presented. The\nmasses have first been extrapolated towards vanishing gluino mass and then to\nthe continuum limit. The final picture is consistent with the formation of\ndegenerate supermultiplets."
    },
    {
        "anchor": "GPUs: An Oasis in the Supercomputing Desert: A novel metric is introduced to compare the supercomputing resources\navailable to academic researchers on a national basis. Data from the\nsupercomputing Top 500 and the top 500 universities in the Academic Ranking of\nWorld Universities (ARWU) are combined to form the proposed \"500/500\" score for\na given country. Australia scores poorly in the 500/500 metric when compared\nwith other countries with a similar ARWU ranking, an indication that HPC-based\nresearchers in Australia are at a relative disadvantage with respect to their\noverseas competitors. For HPC problems where single precision is sufficient,\ncommodity GPUs provide a cost-effective means of quenching the computational\nthirst of otherwise parched Lattice practitioners traversing the Australian\nsupercomputing desert. We explore some of the more difficult terrain in single\nprecision territory, finding that BiCGStab is unreliable in single precision at\nlarge lattice sizes. We test the CGNE and CGNR forms of the conjugate gradient\nmethod on the normal equations. Both CGNE and a modified form of CGNR (with\nrestarts) provide reliable convergence for quark propagator calculations in\nsingle precision.",
        "positive": "O(a^2) corrections to 1-loop matrix elements of 4-fermion operators with\n  improved fermion/gluon actions: We calculate the corrections to the amputated Green's functions of 4-fermion\noperators, in 1-loop Lattice Perturbation theory. The novel aspect of our\ncalculations is that they are carried out to second order in the lattice\nspacing, O(a^2). We employ the Wilson/clover action for massless fermions (also\napplicable for the twisted mass action in the chiral limit) and the Symanzik\nimproved action for gluons. Our calculations have been carried out in a general\ncovariant gauge. Results have been obtained for several popular choices of\nvalues for the Symanzik coefficients (Plaquette, Tree-level Symanzik, Iwasaki,\nTILW and DBW2 action). We pay particular attention to $\\Delta F=2$ operators,\nboth Parity Conserving and Parity Violating ($F$ stands for flavour: S, C, B).\nWe study the mixing pattern of these operators, to O(a^2), using the\nappropriate projectors. Our results for the corresponding renormalization\nmatrices are given as a function of a large number of parameters: coupling\nconstant, clover parameter, number of colors, lattice spacing, external\nmomentum and gauge parameter. The O(a^2) correction terms (along with our\nprevious O(a^2) calculation of $Z_\\Psi$) are essential ingredients for\nminimizing the lattice artifacts which are present in non-perturbative\nevaluations of renormalization constants with the RI'-MOM method. A longer\nwrite-up of this work, including non-perturbative results, is in preparation\ntogether with members of the ETM Collaboration."
    },
    {
        "anchor": "B and D semileptonic decays to light mesons: We present an update of our calculation of the form factors and partial\nwidths of semileptonic heavy-to-light meson decays, in the quenched\napproximation. Our complete data set has now been analysed and our results\ninclude chiral extrapolations and a study of the lattice spacing dependence.",
        "positive": "The Chiral Separation Effect in quenched finite-density QCD: We present results of a study of the Chiral Separation Effect (CSE) in\nquenched finite-density QCD. Using a recently developed numerical method we\ncalculate the conserved axial current for exactly chiral overlap fermions at\nfinite density for the first time. We compute the anomalous transport\ncoefficient for the CSE in the confining and de-confining phase and investigate\npossible deviations from the universal value. In both phases we find that\nnon-perturbative corrections to the CSE are absent and we reproduce the\nuniversal value for the transport coefficient within small statistical errors.\nOur results suggest that the CSE can be used to determine the renormalisation\nfactor of the axial current."
    },
    {
        "anchor": "K pi scattering for isospin 1/2 and 3/2 in lattice QCD: We simulate K pi scattering in s-wave and p-wave for both isospins I=1/2, 3/2\nusing quark-antiquark and meson-meson interpolating fields. We extract the\nelastic phase shifts delta at several values of the K-pi relative momenta. The\nresulting phases exhibit qualitative agreement with the experimental phases in\nall four channels. We express the s-wave phase shifts near threshold in terms\nof the scattering length and the effective range. Our K pi system has zero\ntotal momentum and is simulated on a single ensemble with two dynamical quarks,\nso results apply for mpi=266 MeV and mK=552 MeV in our simulation. The\nbacktracking contractions in both I=1/2 channels are handled by the use of\nLaplacian-Heavyside smeared quarks within the distillation method. Elastic\nphases are extracted from the energy levels using Luscher's relations. In all\nfour channels we observe the expected K(n)pi(-n) scattering states, which are\nshifted due to the interaction. In both attractive I=1/2 channels we observe\nadditional states that are related to resonances; we attribute them to\nK_0^*(1430) in s-wave and K*(892), K*(1410) and K*(1680) in p-wave.",
        "positive": "Running Gluon Mass from Landau Gauge Lattice QCD Propagator: The interpretation of the Landau gauge lattice gluon propagator as a massive\ntype bosonic propagator is investigated. Three different scenarios are\ndiscussed: i) an infrared constant gluon mass; ii) an ultraviolet constant\ngluon mass; iii) a momentum dependent mass. We find that the infrared data can\nbe associated with a massive propagator up to momenta $\\sim 500$ MeV, with a\nconstant gluon mass of 723(11) MeV, if one excludes the zero momentum gluon\npropagator from the analysis, or 648(7) MeV, if the zero momentum gluon\npropagator is included in the data sets. The ultraviolet lattice data is not\ncompatible with a massive type propagator with a constant mass. The scenario of\na momentum dependent gluon mass gives a decreasing mass with the momentum,\nwhich vanishes in the deep ultraviolet region. Furthermore, we show that the\nfunctional forms used to describe the decoupling like solution of the\nDyson-Schwinger equations are compatible with the lattice data with similar\nmass scales."
    },
    {
        "anchor": "Extracting Yang-Mills topological structures with adjoint modes: We report on how adjoint zero modes can be used to filter out the topological\nstructures of gauge configurations from the UV fluctuations. We will use the\nAdjoint Filtering Method (AFM) which relies on the existence of a particular\nSupersymmetric Zero Mode (SZM) that follows closely the (anti)self-dual part of\nthe action density. In contrast, it is not guaranteed that summing over the\nlowest lying modes in the fundamental representation reproduces the topological\ndensity. We present preliminary qualitative results on smooth, heated, and\nMonte-Carlo generated configurations with non-trivial content of fractional\ninstantons. The method is capable of distinguishing the underlying topological\nstructures without significantly modifying the gauge field as opposed to\nsmoothing techniques. The method looks promising as a tool to investigate and\nextend recent studies based on semiclassical methods.",
        "positive": "Observables in Higgsed Theories: In gauge theories, observable quantities have to be gauge-invariant. In\ngeneral, this requires composite operators, which usually have substantially\ndifferent properties, e.g. masses, than the elementary particles. Theories with\na Higgs field, in which the Brout-Englert-Higgs effect is active, provide an\ninteresting exception to this rule. Due to an intricate mechanism, the\nFr\\\"ohlich-Morchio-Strocchi mechanism, the masses of the composite operators\nwith the same $J^P$ quantum numbers, but modified internal quantum numbers,\nhave the same masses. This mechanism is supported using lattice gauge theory\nfor the standard-model Higgs sector, i.e. Yang-Mills-Higgs theory with gauge\ngroup SU(2) and custodial symmetry group SU(2). Furthermore, the extension to\nthe 2-Higgs-doublet-model is briefly discussed, and some preliminary results\nare presented."
    },
    {
        "anchor": "Strong-Isospin Violation in the Neutron-Proton Mass Difference from\n  Fully-Dynamical Lattice QCD and PQQCD: We determine the strong-isospin violating component of the neutron-proton\nmass difference from fully-dynamical lattice QCD and partially-quenched QCD\ncalculations of the nucleon mass, constrained by partially-quenched chiral\nperturbation theory at one-loop level. The lattice calculations were performed\nwith domain-wall valence quarks on MILC lattices with rooted staggered\nsea-quarks at a lattice spacing of b=0.125 fm, lattice spatial size of L=2.5 fm\nand pion masses ranging from m_pi ~ 290 MeV to ~ 350 MeV. At the physical value\nof the pion mass, we predict M_n - M_p |(d-u) = 2.26 +- 0.57 +- 0.42 +- 0.10\nMeV where the first error is statistical, the second error is due to the\nuncertainty in the ratio of light-quark masses, eta=m_u/m_d, determined by\nMILC, and the third error is an estimate of the systematic due to chiral\nextrapolation.",
        "positive": "Novel Bottomonium Results: We present the latest results from the use of the Backus-Gilbert method for\nreconstructing the spectra of NRQCD bottomonium mesons using anisotropic\nFASTSUM ensembles at non-zero temperature. We focus in particular on results\nfrom the $\\eta_b$, $\\Upsilon$, $\\chi_{b1}$ and $h_b$ generated from\nTikhonov-regularized Backus-Gilbert coefficient sets. We extend previous work\non the Laplace shifting theorem as a means of resolution improvement and\npresent new results from its use. We conclude with a discussion of the\nlimitations of the improvement routine and elucidate a connection with\nParisi-Lepage statistical scaling."
    },
    {
        "anchor": "Lattice study of two-dimensional N=(2,2) super Yang-Mills at large-N: We study two-dimensional N=(2,2) SU(N) super Yang-Mills theory on Euclidean\ntwo-torus using Sugino's lattice regularization. We perform the Monte-Carlo\nsimulation for N=2,3,4,5 and then extrapolate the result to N = infinity. With\nthe periodic boundary conditions for the fermions along both circles, we\nestablish the existence of a bound state in which scalar fields clump around\nthe origin, in spite of the existence of a classical flat direction. In this\nphase the global (Z_N)^2 symmetry turns out to be broken. We provide a simple\nexplanation for this fact and discuss its physical implications.",
        "positive": "Weak-coupling analysis of the single-site large-N gauge theory coupled\n  to adjoint fermions: We consider the leading-order expression at weak-coupling for a single-site\nlarge-N gauge theory coupled to adjoint fermions. We study the case of overlap\nand wilson fermions. We extend the theory to real values of the number of\nfermion flavors and restrict ourselves to asymptotically free theories. Using a\nfour-dimensional density function for the distribution of the eigenvalues of\nthe link variables, we show that it is possible to recover the infinite-volume\ncontinuum limit for a certain range of fermion flavors if we use fermions with\na bare mass of zero. Our use of the four-dimensional density function is\nsupported by a direct analysis of the lattice action."
    },
    {
        "anchor": "Ising Spins on Thin Graphs: The Ising model on ``thin'' graphs (standard Feynman diagrams) displays\nseveral interesting properties. For ferromagnetic couplings there is a mean\nfield phase transition at the corresponding Bethe lattice transition point. For\nantiferromagnetic couplings the replica trick gives some evidence for a spin\nglass phase. In this paper we investigate both the ferromagnetic and\nantiferromagnetic models with the aid of simulations. We confirm the Bethe\nlattice values of the critical points for the ferromagnetic model on $\\phi^3$\nand $\\phi^4$ graphs and examine the putative spin glass phase in the\nantiferromagnetic model by looking at the overlap between replicas in a\nquenched ensemble of graphs. We also compare the Ising results with those for\nhigher state Potts models and Ising models on ``fat'' graphs, such as those\nused in 2D gravity simulations.",
        "positive": "Testing volume independence of SU(N) pure gauge theories at large N: In this paper we present our results concerning the dependence of Wilson loop\nexpectation values on the size of the lattice and the rank of the SU(N) gauge\ngroup. This allows to test the claims about volume independence in the large N\nlimit, and the crucial dependence on boundary conditions. Our highly precise\nresults provide strong support for the validity of the twisted reduction\nmechanism and the TEK model, provided the fluxes are chosen within the\nappropriate domain."
    },
    {
        "anchor": "Witten index and phase diagram of compactified N=1 supersymmetric\n  Yang-Mills theory on the lattice: Owing to confinement, the fundamental particles of N=1 Supersymmetric\nYang-Mills (SYM) theory, gluons and gluinos, appear only in colourless bound\nstates at zero temperature. Compactifying the Euclidean time dimension with\nperiodic boundary conditions for fermions preserves supersymmetry, and\nconfinement is predicted to persist independently of the length of the\ncompactified dimension. This scenario can be tested non-perturbatively with\nMonte-Carlo simulations on a lattice. SUSY is, however, broken on the lattice\nand can be recovered only in the continuum limit. The partition function of\ncompactified N=1 SYM theory with periodic fermion boundary conditions\ncorresponds to the Witten index. Therefore it can be used to test whether\nsupersymmetry is realized on the lattice. Results of our recent numerical\nsimulations are presented, supporting the disappearance of the deconfinement\ntransition in the supersymmetric limit and the restoration of SUSY at low\nenergies.",
        "positive": "K-meson vector and tensor decay constants and BK-parameter from Nf=2\n  tmQCD: We present work in progress on the computation of the K-meson vector and\ntensor decay constants, as well as the B-parameter in Kaon oscillations. Our\nsimulations are performed in a partially quenched setup, with two dynamical\n(sea) Wilson quark flavours, having a maximally twisted mass term. Valence\nquarks are either of the standard or the Osterwalder-Seiler maximally twisted\nvariety. These two regularizations can be suitably combined in order to obtain\na BK parameter which is both multiplicatively renormalizable and O(a) improved."
    },
    {
        "anchor": "Sea contributions to the electric polarizability of the hadrons: We present a lattice QCD calculation of the polarizability of the neutron and\nother neutral hadrons that includes the effects of the background field on the\nsea quarks. This is done by perturbatively reweighting the charges of the sea\nquarks to couple them to the background field. The main challenge in such a\ncalculation is stochastic estimation of the weight factors, and we discuss the\ndifficulties in this estimation. Here we use an extremely aggressive dilution\nscheme to reduce the stochastic noise to a manageable level. The pion mass in\nour calculation is 306 MeV and the lattice size is 3 fm. For neutron, we find\nthat $\\alpha_E = 2.70(55) * 10^{-4}fm^3$, which is the most precise lattice QCD\ndetermination of the polarizability to date that includes sea effects.",
        "positive": "Exact solution (by algebraic methods) of the lattice Schwinger model in\n  the strong-coupling regime: Using the monomer--dimer representation of the lattice Schwinger model, with\n$N_f =1$ Wilson fermions in the strong--coupling regime ($\\beta=0$), we\nevaluate its partition function, $Z$, exactly on finite lattices. By studying\nthe zeroes of $Z(k)$ in the complex plane $(Re(k),Im(k))$ for a large number of\nsmall lattices, we find the zeroes closest to the real axis for infinite\nstripes in temporal direction and spatial extent $S=2$ and 3. We find evidence\nfor the existence of a critical value for the hopping parameter in the\nthermodynamic limit $S\\rightarrow \\infty$ on the real axis at about $k_c \\simeq\n0.39$. By looking at the behaviour of quantities, such as the chiral\ncondensate, the chiral susceptibility and the third derivative of $Z$ with\nrespect to $1/2k$, close to the critical point $k_c$, we find some indications\nfor a continuous phase transition."
    },
    {
        "anchor": "Note on lattice regularization and equal-time correlators for parton\n  distribution functions: We show that a recent interesting idea to circumvent the difficulties with\nthe continuation of parton distribution functions to the Euclidean region, that\nconsists in looking at equal time correlators between proton states of infinite\nmomentum, encounters some problems related to the power divergent mixing\npattern of DIS operators, when implemented within the lattice regularization.",
        "positive": "Two- and three-pion finite-volume spectra at maximal isospin from\n  lattice QCD: We present the three-pion spectrum with maximal isospin in a finite volume\ndetermined from lattice QCD, including excited states in addition to the ground\nstates across various irreducible representations at zero and nonzero total\nmomentum. The required correlation functions, from which the spectrum is\nextracted, are computed using a newly implemented algorithm which speeds up the\ncomputation by more than an order of magnitude. On a subset of the data we\nextract a nonzero value of the three-pion threshold scattering amplitude using\nthe $1/L$ expansion of the three-particle quantization condition, which\nconsistently describes all states at zero total momentum. The finite-volume\nspectrum is publicly available to facilitate further explorations within the\navailable three-particle finite-volume approaches."
    },
    {
        "anchor": "Lattice QCD at Finite Temperature and Density: A general introduction into the subject aimed at a general theoretical\nphysics audience. We introduce the sign problem posed by finite density lattice\nQCD, and we discuss the main methods proposed to circumvent it, with emphasis\non the imaginary chemical potential approach. The interrelation between the\nTaylor expansion and the analytic continuation from imaginary chemical\npotential is discussed in detail. The main applications to the calculation of\nthe critical line, and to the thermodynamics of the hot and the hadronic phase\nare reviewed.",
        "positive": "Finite Size Effects in Quark-Gluon Plasma Formation: Using lattice simulations of quenched QCD we estimate the finite size effects\npresent when a gluon plasma equilibrates in a slab geometry, i.e., finite width\nbut large transverse dimensions. Significant differences are observed in the\nfree energy density for the slab when compared with bulk behavior. A small\nshift in the critical temperature is also seen. The free energy required to\nliberate heavy quarks relative to bulk is measured using Polyakov loops; the\nadditional free energy required is on the order of $30-40 MeV$ at $2-3 T_c$."
    },
    {
        "anchor": "The kaon mass in 2+1+1 flavor twisted mass Wilson ChPT: We construct the chiral low-energy effective theory for 2+1+1 flavor lattice\nQCD with twisted mass Wilson fermions. In contrast to existing results we\nassume a heavy charm quark mass such that the D mesons are too heavy to appear\nas degrees of freedom in the effective theory. As an application we compute the\nkaon mass to 1-loop order in the LCE regime. The result contains a chiral\nlogarithm involving the neutral pion mass which has no analogue in continuum\nChPT.",
        "positive": "Heavy Quark Momentum Diffusion Coefficient from Lattice QCD: The momentum diffusion coefficient for heavy quarks is studied in a\ndeconfined gluon plasma in the static approximation by investigating a\ncorrelation function of the color electric field using Monte Carlo techniques.\nThe diffusion coefficient is extracted from the long distance behavior of such\na correlator. For temperatures Tc < T <~ 2 Tc, our nonperturbative estimate of\nthe diffusion coefficient is found to be very different from the leading order\nperturbation theory, and is in the right ballpark to explain the heavy quark\nflow seen by PHENIX at RHIC."
    },
    {
        "anchor": "First results on QCD thermodynamics with HISQ action: We report on investigations of the chiral and deconfinement aspects of the\nfinite temperature transition in 2+1 flavor QCD using the Highly Improved\nStaggered Quark (HISQ) action on lattices with temporal extent $N_\\tau=6$ and\n$N_\\tau=8$. We have calculated several physical observables, including the\nrenormalized Polyakov loop, strangeness fluctuations, the renormalized chiral\ncondensate and the chiral susceptibility in the crossover region for physical\nvalues of the strange quark mass $m_s$ and light quark masses $m_l=0.2m_s$ and\n$0.05m_s$. We compare our findings with previous calculations that use\ndifferent improved staggered fermion formulations: asqtad, p4 and stout.",
        "positive": "Theta vacuum effects on the chiral condensation and the eta^prime meson\n  correlators in the two-flavor massive QED_2 on the lattice: We study the scalar and pseudoscalar condensations and the eta^prime meson\ncorrelators of the two-flavor massive Schwinger model in the non-zero theta\nvacuum. Exploiting our new method which was developed to investigate\ntopological effects in the previous work, we find that the pseudoscalar\ncondensation is non-zero and there exists a long-range correlation of the\neta^prime meson. This phenomenon is well described by the clustering property.\nWe also find that even in theta=0 case the cancellation of the long-range\ncorrelation is nontrivial and requires accurate contributions from higher\ntopological sectors. Our results imply that the fluctuation of the\n``disconnected'' diagram originates from the pseudoscalar condensation in each\ntopological sector."
    },
    {
        "anchor": "Gluons in Two-Color QCD at High Baryon Density: Landau gauge longitudinal and transverse gluon propagators are studied in\nlattice QCD with gauge group $SU(2)$ at varying temperature and quark density.\nIn particular, it is found that the longitudinal propagator decreases with\nincreasing quark chemical potential at all temperatures under study, whereas\nthe transverse propagator increases with increasing quark chemical potential at\n$T<200$ MeV and does not depend on it at higher temperatures. The relative\nstrength of chromoelectric and chromomagnetic interactions is also discussed.",
        "positive": "QCD spectroscopy with three light quarks: We report about a simulation using three dynamical Wilson quarks and on the\nprogress in going to small quark masses."
    },
    {
        "anchor": "Lattice energy sum rules and the trace anomaly: We show that the additional contribution to the Michael lattice energy sum\nrule for the static quark-antiquark potential, pointed out recently, can be\nidentified with the contribution to the field energy arising from the trace\nanomaly of the energy momentum tensor. We also exlicitely exhibit the anomalous\ncontribution to the field energy in the sum rule for the glueball mass obtained\nrecently by Michael.",
        "positive": "Perturbative Thermodynamics of Lattice QCD with Chiral-Invariant\n  Four-Fermion Interactions: Lattice QCD with additional chiral-invariant four-fermion interactions is\nstudied at nonzero temperature. Staggered Kogut-Susskind quarks are used. The\nfour-fermion interactions are implemented by introducing bosonic auxiliary\nfields. A mean field treatment of the auxiliary fields is used to calculate the\nmodel's asymptotic scale parameter and perturbative thermodynamics, including\nthe one-loop gluonic contributions to the energy, entropy, and pressure. In\nthis approach the calculations reduce to those of ordinary lattice QCD with\nmassive quarks. Hence, the previous calculations of these quantities in lattice\nQCD using massless quarks are generalized to the massive case."
    },
    {
        "anchor": "The Equation of State for QCD with 2+1 Flavors of Quarks: We report results for the interaction measure, pressure and energy density\nfor nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In\nour simulations we use a Symanzik improved gauge action and the Asqtad $O(a^2)$\nimproved staggered quark action for lattices with temporal extent $N_t=4$ and\n6. The heavy quark mass $m_s$ is fixed at approximately the physical strange\nquark mass and the two degenerate light quarks have masses $m_{ud} =0.1m_s$ or\n$0.2m_s$. The calculation of the thermodynamic observables employs the integral\nmethod where energy density and pressure are obtained by integration over the\ninteraction measure.",
        "positive": "Monopoles and Spatial String Tension in the High Temperature Phase of\n  SU(2) QCD: We studied a behavior of monopole currents in the high temperature\n(deconfinement) phase of abelian projected finite temperature SU(2) QCD in\nmaximally abelian gauge. Wrapped monopole currents closed by periodic boundary\nplay an important role for the spatial string tension which is a\nnon-perturbative quantity in the deconfinement phase. The wrapped monopole\ncurrent density seems to be non-vanishing in the continuum limit. These results\nmay be related to Polyakov's analysis of the confinement mechanism using\nmonopole gas in 3-dimensional SU(2) gauge theory with Higgs fields."
    },
    {
        "anchor": "The quenched limit of lattice QCD at non-zero baryon number: We discuss the thermodynamics of gluons in the background of static quark\nsources. In order to do so we formulate the quenched limit of QCD at non-zero\nbaryon number. A first numerical analysis of this system shows that it\nundergoes a smooth deconfining transition. We find evidence for a region of\ncoexisting phases that becomes broader with increasing baryon number density.\nAlthough the action is in our formulation explicitly Z(3) symmetric the\nPolyakov loop expectation value becomes non-zero already in the low temperature\nphase. It indicates that the heavy quark potential stays finite at large\ndistances, ie. the string between static quarks breaks at non-zero baryon\nnumber density already in the hadronic phase.",
        "positive": "Form factors for semileptonic $B\\to\u03c0$, $B_s\\to K$ and $B_s\\to D_s$\n  decays: We report on our determinations of $B\\to \\pi\\ell\\nu$, $B_s\\to K \\ell \\nu$ and\n$B_s\\to D_s \\ell \\nu$ semileptonic form factors. In addition we discuss the\ndetermination of $R$-ratios testing lepton-flavor universality and suggest an\nimproved ratio. Our calculations are based on the set of 2+1 flavor domain-wall\nIwasaki gauge field configurations generated by the RBC/UKQCD collaboration\nwith three lattice spacings of $1/a = 1.78$, $2.38$, and $2.79\\,\\text{GeV}$. We\nuse the relativistic heavy quark action for $b$ quarks and charm quarks are\nsimulated with the M\\\"obius domain-wall fermion action."
    },
    {
        "anchor": "Quark confinement and the bosonic string: Using a new type of simulation algorithm for the standard SU(3) lattice gauge\ntheory that yields results with unprecedented precision, we confirm the\npresence of a $\\gamma/r$ correction to the static quark potential at large\ndistances $r$, with a coefficient $\\gamma$ as predicted by the bosonic string\ntheory. In both three and four dimensions, the transition from perturbative to\nstring behaviour is evident from the data and takes place at surprisingly small\ndistances.",
        "positive": "Eigenvalue distribution of the Dirac operator at finite temperature with\n  (2+1)-flavor dynamical quarks using the HISQ action: We report on the behavior of the eigenvalue distribution of the Dirac\noperator in (2+1)-flavor QCD at finite temperature, using the HISQ action. We\ncalculate the eigenvalue density at several values of the temperature close to\nthe pseudocritical temperature. For this study we use gauge field\nconfigurations generated on lattices of size $32^3 \\times 8$ with two light\nquark masses corresponding to pion masses of about 160 and 115 MeV. We find\nthat the eigenvalue density below $T_c$ receives large contributions from\nnear-zero modes which become smaller as the temperature increases or the light\nquark mass decreases. Moreover we find no clear evidence for a gap in the\neigenvalue density up to 1.1$T_c$. We also analyze the eigenvalue density near\n$T_c$ where it appears to show a power-law behavior consistent with what is\nexpected in the critical region near the second order chiral symmetry restoring\nphase transition in the massless limit."
    },
    {
        "anchor": "Deflated Multigrid Multilevel Monte Carlo: In lattice QCD, the trace of the inverse of the discretized Dirac operator\nappears in the disconnected fermion loop contribution to an observable. As\nsimulation methods get more and more precise, these contributions become\nincreasingly important. Hence, we consider here the problem of computing the\ntrace $\\mathrm{tr}(D^{-1})$, with $D$ the Dirac operator. The Hutchinson\nmethod, which is very frequently used to stochastically estimate the trace of a\nfunction of a matrix, approximates the trace as the average over estimates of\nthe form $x^{H} D^{-1} x$, with the entries of the vector $x$ following a\ncertain probability distribution. For $N$ samples, the accuracy is\n$\\mathcal{O}(1/\\sqrt{N})$. In recent work, we have introduced multigrid\nmultilevel Monte Carlo: having a multigrid hierarchy with operators $D_{\\ell}$,\n$P_{\\ell}$ and $R_{\\ell}$, for level $\\ell$, we can rewrite the trace\n$\\mathrm{tr}(D^{-1})$ via a telescopic sum with difference-levels, written in\nterms of the aforementioned operators and with a reduced variance. We have seen\nsignificant reductions in the variance and the total work with respect to\nexactly deflated Hutchinson. In this work, we explore the use of exact\ndeflation in combination with the multigrid multilevel Monte Carlo method, and\ndemonstrate how this leads to both algorithmic and computational gains.",
        "positive": "Towards models with a unified dynamical mechanism for elementary\n  particle masses: Numerical evidence for a new dynamical mechanism of elementary particle mass\ngeneration has been found by lattice simulation in a simple, yet highly\nnon-trivial SU(3) gauge model where a SU(2) doublet of strongly interacting\nfermions is coupled to a complex scalar field doublet via a Yukawa and a\nWilson-like term. We point out that if, as a next step towards the construction\nof a realistic beyond-the-Standard-Model model, weak interactions are\nintroduced, then also weak bosons get a mass by the very same non-perturbative\nmechanism. In this scenario fermion mass hierarchy can be naturally understood\nowing to the peculiar gauge coupling dependence of the non-perturbatively\ngenerated masses. Hence, if the phenomenological value of the mass of the top\nquark or the weak bosons has to be reproduced, the RGI scale of the theory must\nbe much larger than $\\Lambda_{QCD}$. This feature hints at the existence of new\nstrong interactions and particles at a scale $\\Lambda_T$ of a few TeV. In such\na speculative framework the electroweak scale can be derived from the basic\nscale $\\Lambda_T$ and the Higgs boson should arise as a bound state in the\n$WW+ZZ$ channel."
    },
    {
        "anchor": "Next-to-Leading-Order Staggered Chiral Perturbation Theory: We have extended staggered chiral perturbation theory to O(a^2 p^2), O(a^4),\nand O(a^2 m), the orders necessary for a full next-to-leading order calculation\nof pseudo-Goldstone boson masses and decay constants including taste-symmetry\nviolations. We present predictions relating SO(4) taste-breaking splittings in\nmasses, pseudoscalar decay constants, and dispersion relations. These can be\nused to test the fourth-root trick.",
        "positive": "Lattice QCD results for the topological up-quark mass contribution: too\n  small to rescue the $m_u=0$ solution to the strong CP problem: A vanishing Yukawa coupling of the up quark could in principle solve the\nstrong CP problem. To render this solution consistent with current algebra\nresults, the up quark must receive an alternative mass contribution that\nconserves CP symmetry. Such a contribution could be provided by QCD through\nnon-perturbative topological effects, including instantons. In this talk, we\npresent the first direct lattice computation of this topological mass\ncontribution, using gauge configurations generated by the Extended Twisted Mass\ncollaboration. We use the Iwasaki gauge action, Wilson twisted mass fermions at\nmaximal twist, and dynamical up, down, strange and charm quarks. Our result for\nthe topological mass contribution is an order of magnitude too small to account\nfor the phenomenologically required up-quark mass. This rules out the\n\"massless\" up-quark solution to the strong CP problem, in accordance with\nprevious results relying on $\\chi$PT fits to lattice data. The talk is based on\n[Alexandrou et al., PRL 125, 232001 (2020)], where more details can be found."
    },
    {
        "anchor": "Simulating dynamical fermions with smeared links: Smearing the gauge links of dynamical configurations removes small scale\nunphysical vacuum fluctuations and thus improves the chiral properties of\nlattice fermions. Recently we proposed the hypercubic smearing (HYP) that\nimproves the flavor symmetry of staggered fermions by an order of magnitude\nwith only minimal distortions at small distances. We describe a new algorithm\nto simulate dynamical HYP fermions based on the standard pure gauge\noverrelaxation and heatbath updates. The algorithm has been used to simulate\nfour and two flavors of staggered fermions. Unlike standard dynamical\nsimulation techniques, this algorithm does not loose efficiency at small quark\nmasses.",
        "positive": "Multicanonical Ensemble: A New Approach to Simulate First-order Phase\n  Transitions: Relying on the recently proposed multicanonical algorithm, we present a\nnumerical simulation of the first order phase transition in the 2d 10-state\nPotts model on lattices up to sizes $100\\times100$. It is demonstrated that the\nnew algorithm $lacks$ an exponentially fast increase of the tunneling time\nbetween metastable states as a function of the linear size $L$ of the system.\nInstead, the tunneling time diverges approximately proportional to $L^{2.65}$.\nThus the computational effort as counted per degree of freedom for generating\nan independent configuration in the unstable region of the model rises\nproportional to $V^{2.3}$, where $V$ is the volume of the system. On our\nlargest lattice we gain more than two orders of magnitude as compared to a\nstandard heat bath algorithm. As a first physical application we report a high\nprecision computation of the interfacial tension."
    },
    {
        "anchor": "Antiferromagnetism in four dimensions: search for non-triviality: We present antiferromagnetism as a mechanism capable of modifying\nsubstantially the phase diagram and the critical behaviour of statistical\nmechanical models. This is particularly relevant in four dimensions, due to the\nconnection between second order transition points and the continuum limit as a\nquantum field theory. We study three models with an antiferromagnetic\ninteraction: the Ising and the O(4) Models with a second neighbour negative\ncoupling, and the $\\RP{2}$ Model. Different conclusions are obtained depending\non the model.",
        "positive": "Wavelets and Lattice Field Theory: When continuous fields are expanded in a wavelet basis, a D-dimensional\ncontinuum action becomes a (D+1)-dimensional lattice action on the naively\ndiscretized Poincare-patch coordinates of an Euclidean AdS(D+1). New possible\ncriteria for acceptable actions open up."
    },
    {
        "anchor": "SU(2) Gauge Theory with Two Fundamental Flavours: a Minimal Template for\n  Model Building: We investigate the continuum spectrum of the SU(2) gauge theory with $N_f=2$\nflavours of fermions in the fundamental representation. This model provides a\nminimal template which is ideal for a wide class of Standard Model extensions\nfeaturing novel strong dynamics that range from composite (Goldstone) Higgs\ntheories to several intriguing types of dark matter candidates, such as the\nSIMPs. We improve our previous lattice analysis [1] by adding more data at\nlight quark masses, at two additional lattice spacings, by determining the\nlattice cutoff via a Wilson flow measure of the $w_0$ parameter, and by\nmeasuring the relevant renormalisation constants non-perturbatively in the\nRI'-MOM scheme. Our results for the lightest isovector states in the vector and\naxial channels, in units of the pseudoscalar decay constant, are\n$m_V/F_{\\rm{PS}}\\sim 13.1(2.2)$ and $m_A/F_{\\rm{PS}}\\sim 14.5(3.6)$ (combining\nstatistical and systematic errors).\n  In the context of the composite (Goldstone) Higgs models, our result for the\nspin-one resonances are $m_V > 3.2(5)$ TeV and $m_A > 3.6(9)$ TeV, which are\nabove the current LHC constraints. In the context of dark matter models, for\nthe SIMP case our results indicate the occurrence of a compressed spectrum at\nthe required large dark pion mass, which implies the need to include the\neffects of spin-one resonances in phenomenological estimates.",
        "positive": "Systematic Effects at Criticality for the SU(2)-Landau-Gauge Gluon\n  Propagator: We analyze data from finite-temperature simulations of the gluon propagator\nin SU(2) Landau gauge on large lattices. We argue that the singular behavior of\nthis quantity around the deconfinement transition, seen in several previous\nstudies, is a lattice artifact."
    },
    {
        "anchor": "Fermion Number Conservation Isn't Fermion Conservation: A nonperturbative regularization of the Standard Model may have a\nsuperficially undesirable exact global U(1) symmetry corresponding to exact\nfermion number conservation. We argue that such a formulation can still have\nthe desired physics of fermion nonconservation, i.e. fermion particle creation\nand annihilation by sphaleron transitions. We illustrate our reasoning in\nmassless axial QED in 1+1 dimensions.",
        "positive": "2022 Update on $\\varepsilon_K$ with lattice QCD inputs: We present recent updates for $\\varepsilon_K$ determined directly from the\nstandard model (SM) with lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $f_K$, and $m_c$. We find that\nthe standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs\ndescribes only 65% of the experimental value of $|\\varepsilon_K|$ and does not\nexplain its remaining 35%, which leads to a strong tension in $|\\varepsilon_K|$\nat the $5.1\\sigma \\sim 3.9\\sigma$ level between the SM theory and experiment.\nWe also find that this tension disappears when we use the inclusive value of\n$|V_{cb}|$ obtained using the heavy quark expansion based on the QCD sum rule\napproach, although this inclusive tension is small ($\\approx 1.4\\sigma$) but\nkeeps increasing as time goes on."
    },
    {
        "anchor": "Geometry dependence of RMT-based methods to extract the low-energy\n  constants Sigma and F: The lowest-order low-energy constants $\\Sigma$ and $F$ of chiral pertubation\ntheory can be extracted from lattice data using methods based on the\nequivalence of random matrix theory (RMT) and QCD in the epsilon regime. We\ndiscuss how the choice of the lattice geometry affects such methods. In\nparticular, we show how to minimize systematic deviations from RMT by an\noptimal choice of the lattice geometry in the case of two light quark flavors.\nWe illustrate our findings by determining $\\Sigma$ and $F$ from lattice\nconfigurations with two dynamical overlap fermions generated by JLQCD, using\ntwo different lattice geometries.",
        "positive": "Joint Contour Net Analysis for Feature Detection in Lattice Quantum\n  Chromodynamics Data: In this paper we demonstrate the use of multivariate topological algorithms\nto analyse and interpret Lattice Quantum Chromodynamics (QCD) data. Lattice QCD\nis a long established field of theoretical physics research in the pursuit of\nunderstanding the strong nuclear force. Complex computer simulations model\ninteractions between quarks and gluons to test theories regarding the behaviour\nof matter in a range of extreme environments. Data sets are typically generated\nusing Monte Carlo methods, providing an ensemble of configurations, from which\nobservable averages must be computed. This presents issues with regard to\nvisualisation and analysis of the data as a typical ensemble study can generate\nhundreds or thousands of unique configurations. We show how multivariate\ntopological methods, such as the Joint Contour Net, can assist physicists in\nthe detection and tracking of important features within their data in a\ntemporal setting. This enables them to focus upon the structure and\ndistribution of the core observables by identifying them within the surrounding\ndata. These techniques also demonstrate how quantitative approaches can help\nunderstand the lifetime of objects in a dynamic system."
    },
    {
        "anchor": "Compact QED in Landau Gauge: a lattice gauge fixing case study: We derive different representations of compact QED fixed to Landau gauge by\nthe lattice Faddeev-Popov procedure. Our analysis finds that (A)Nielsen-Olesen\nvortices arising from the compactness of the gauge-fixing action are {\\it\nquenched\\/}, that is, the Faddeev-Popov determinant cancels them out and they\ndo not influence correlation functions such as the photon propagator; (B)Dirac\nstrings are responsible for the nonzero mass pole of the photon propagator.\nSince in $D=3+1$ the photon mass undergoes a rapid drop to zero at $\\beta_c$,\nthe deconfinement point, this result predicts that Dirac strings must be\nsufficiently dilute at $\\beta > \\beta_c$. Indeed, numerical simulations reveal\nthat the string density undergoes a rapid drop to near zero at $\\beta\\sim\n\\beta_c$.",
        "positive": "Nucleon form factors on the lattice with light dynamical fermions: The electromagnetic form factors provide important insight into the internal\nstructure of the nucleon and continue to be of major interest for experiment\nand phenomenology. For an intermediate range of momenta the form factors can be\ncalculated on the lattice. However, the reliability of the results is limited\nby systematic errors mostly due to the required extrapolation to physical quark\nmasses. Chiral effective field theories predict a rather strong quark mass\ndependence in a range which was yet inaccessible for lattice simulations. We\ngive an update on recent results from the QCDSF collaboration using gauge\nconfigurations with dynamical Nf=2, non-perturbatively O(a)-improved Wilson\nfermions at pion masses as low as 350 MeV."
    },
    {
        "anchor": "International Lattice Data Grid: Turn on, plug in,and download: In the beginning there was the internet, then came the world wide web, and\nnow there is the grid. In the future perhaps there will be the cloud. In the\nage of persistent, pervasive, and pandemic networks I review how the lattice\nQCD community embraced the open source paradigm for both code and data whilst\nadopting the emerging grid technologies, and why having your data persistently\naccessible via standardized protocols and services might be a good idea.",
        "positive": "Lattice renormalisation of O(a) improved heavy-light operators: an\n  addendum: The analytical expressions and the numerical values of the renormalisation\nconstants of dimension 3 static-light currents are given at one-loop order of\nperturbation theory in the framework of Heavy Quark Effective Theory and with\nan improved gauge action: the static quark is described by the HYP-smeared\naction and the light quark is of Wilson kind. This completes a work started few\nyears ago and is actually an intermediate step in the measurement of the decay\nconstants $f_{B}$ and $f_{B_{s}}$ by the European Twisted Mass Collaboration\n[arXiv:1107.1441[hep-lat]]."
    },
    {
        "anchor": "Accurate Checks of Universality for Dyson's Hierarchical Model: Using recently developed methods, we perform high-accuracy calculations of\nthe susceptibility near beta_c for the D=3 version of Dyson's hierarchical\nmodel. Using linear fits, we estimate the leading gamma and subleading Delta\nexponents. Independent estimates are obtained by calculating the first two\neigenvalues of the linearized renormalization group transformation. We found\ngamma = 1.29914073 (with an estimated error of 10^{-8}) and, Delta=0.4259469\n(with an estimated error of 10^{-7}) independently of the choice of local\nintegration measure (Ising or Landau-Ginzburg). After a suitable rescaling, the\napproximate fixed points for a large class of local measure coincide accurately\nwith a fixed point constructed by Koch and Wittwer.",
        "positive": "Propagators in Coulomb gauge from SU(2) lattice gauge theory: A thorough study of 4-dimensional SU(2) Yang-Mills theory in Coulomb gauge is\nperformed using large scale lattice simulations. The (equal-time) transverse\ngluon propagator, the ghost form factor d(p) and the Coulomb potential V_{coul}\n(p) ~ d^2(p) f(p)/p^2 are calculated. For large momenta p, the gluon propagator\ndecreases like 1/p^{1+\\eta} with \\eta =0.5(1). At low momentum, the propagator\nis weakly momentum dependent. The small momentum behavior of the Coulomb\npotential is consistent with linear confinement. We find that the inequality\n\\sigma_{coul} \\ge \\sigma comes close to be saturated. Finally, we provide\nevidence that the ghost form factor d(p) and f(p) acquire IR singularities,\ni.e., d(p) \\propto 1/\\sqrt{p} and f(p) \\propto 1/p, respectively. It turns out\nthat the combination g_0^2 d_0(p) of the bare gauge coupling g_0 and the bare\nghost form factor d_0(p) is finite and therefore renormalization group\ninvariant."
    },
    {
        "anchor": "ADJOINT \"QUARK\" COLOR FIELDS IN FOUR-DIMENSIONAL LATTICE GAUGE THEORY:\n  VACUUM SCREENING AND PENETRATION: The fields generated by ``quarks'' in the adjoint representation of SU(2)\ncolor are analyzed in the scaling region of the four-dimensional lattice\ntheory. Evidence of vacuum screening of adjoint quarks is obtained from a\ncomparison of quark-antiquark ($Q \\bar Q$) flux-tubes for quarks in the adjoint\n(``isospin'' $j=1$) and fundamental ($j=1/2$) representations. The component\n${\\cal E}_j$ of the color-electric field strength in the direction parallel to\nthe $Q \\bar Q$ axis is calculated. Near the quarks the ratio of fields ${\\cal\nE}_{j=1} / {\\cal E}_{j=1/2}$ approaches the value 8/3, which is equal to the\nratio of SU(2) Casimirs. In between the quarks, the ratio falls well below 8/3\nat large $R$. ${\\cal E}_j$ also falls off rapidly as a function of distance\n$x_\\perp$ perpendicular to the $Q \\bar Q$ axis. However, the ratio ${\\cal\nE}_{j=1} / {\\cal E}_{j=1/2}$ depends very weakly on $x_\\perp$. The flux-tubes\nin the two representations thus appear to have very similar cross-sections.\nThis result could imply that the QCD vacuum is dual to a type I superconductor.",
        "positive": "Universal Aspects of Deconfinement: Interfaces, Flux Tubes and\n  Self-Duality in 2+1 Dimensions: We study center vortex free energies and 't Hooft's electric fluxes on the\nlattice in 2+1 dimensions, where SU(2) for example, is in the universality\nclass of the 2d Ising model. This places a wealth of exact results at our\nfingertips. In particular, spacelike center vortices in SU(2) near criticality\ncorrespond to spin interfaces in the 2d Ising model, whose universal scaling\nfunctions are known exactly. We exploit this to locate the deconfinement\ntransition with unprecedented precision and subsequently for a finite size\nscaling analysis, where the self-duality of the $2d$ spin model is reflected in\na duality between the spacelike vortices and confining electric fluxes. The\ncorresponding relation between the string tension and its dual in the high\ntemperature phase is arguably the simplest example of a universal amplitude\nratio. Around the transition, both can be efficiently extracted from the exact\nresults with a global one-parameter fit which allows straightforward continuum\nextrapolation."
    },
    {
        "anchor": "The lattice ghost propagator in Landau gauge up to three loops using\n  Numerical Stochastic Perturbation Theory: We complete our high-accuracy studies of the lattice ghost propagator in\nLandau gauge in Numerical Stochastic Perturbation Theory up to three loops. We\npresent a systematic strategy which allows to extract with sufficient precision\nthe non-logarithmic parts of logarithmically divergent quantities as a function\nof the propagator momentum squared in the infinite-volume and $a\\to 0$ limits.\nWe find accurate coincidence with the one-loop result for the ghost self-energy\nknown from standard Lattice Perturbation Theory and improve our previous\nestimate for the two-loop constant contribution to the ghost self-energy in\nLandau gauge. Our results for the perturbative ghost propagator are compared\nwith Monte Carlo measurements of the ghost propagator performed by the Berlin\nHumboldt university group which has used the exponential relation between\npotentials and gauge links.",
        "positive": "Monte Carlo simulation of lattice ${\\rm CP}^{N-1}$ models at large N: In order to check the validity and the range of applicability of the 1/N\nexpansion, we performed numerical simulations of the two-dimensional lattice\nCP(N-1) models at large N, in particular we considered the CP(20) and the\nCP(40) models. Quantitative agreement with the large-N predictions is found for\nthe correlation length defined by the second moment of the correlation\nfunction, the topological susceptibility and the string tension. On the other\nhand, quantities involving the mass gap are still far from the large-$N$\nresults showing a very slow approach to the asymptotic regime. To overcome the\nproblems coming from the severe form of critical slowing down observed at large\nN in the measurement of the topological susceptibility by using standard local\nalgorithms, we performed our simulations implementing the Simulated Tempering\nmethod."
    },
    {
        "anchor": "On reflection positive formulation of chiral gauge theories on a lattice: A formulation of chiral gauge theories on a lattice which is both reflection\npositive and gauge invariant is discussed.",
        "positive": "Low-dimensional Supersymmetric Lattice Models: We study and simulate N=2 supersymmetric Wess-Zumino models in one and two\ndimensions. For any choice of the lattice derivative, the theories can be made\nmanifestly supersymmetric by adding appropriate improvement terms corresponding\nto discretizations of surface integrals. In one dimension, our simulations show\nthat a model with the Wilson derivative and the Stratonovitch prescription for\nthis discretization leads to far better results at finite lattice spacing than\nother models with Wilson fermions considered in the literature. In particular,\nwe check that fermionic and bosonic masses coincide and the unbroken Ward\nidentities are fulfilled to high accuracy. Equally good results for the\neffective masses can be obtained in a model with the SLAC derivative (even\nwithout improvement terms).\n  In two dimensions we introduce a non-standard Wilson term in such a way that\nthe discretization errors of the kinetic terms are only of order O(a^2). Masses\nextracted from the corresponding manifestly supersymmetric model prove to\napproach their continuum values much quicker than those from a model containing\nthe standard Wilson term. Again, a comparable enhancement can be achieved in a\ntheory using the SLAC derivative."
    },
    {
        "anchor": "On the equivalence between the Wilson flow and stout-link smearing: We present the numerical equivalence between the Wilson flow and stout-link\nsmearing, both of which are known to be a relatively new technique for\nsmoothing the gauge fields on the lattice. Although the conceptional\ncorrespondence between two methods was first pointed out by L\\\"uscher in his\noriginal paper [J. High Energy Phys.~08 (2010) 071], we provide a direct\nanalytical proof of the equivalence between the two methods at finite lattice\nspacing $a$ in the zero limit of the stout-smearing parameter $\\rho$. The\nleading order corrections start at ${\\cal O}(\\rho)$, which would induce ${\\cal\nO}(a^2)$ corrections. It is, therefore, not obvious that they remain equivalent\neven with finite parameters ($a\\neq 0$ and $\\rho\\neq0$) within some numerical\nprecision. In this paper, we demonstrate the equivalence of both methods by\ndirectly comparing the expectation value of the action density, which is\nmeasured in actual numerical simulations.",
        "positive": "Scattering from finite size methods in lattice QCD: Using two flavors of maximally twisted mass fermions, we calculate the S-wave\npion-pion scattering length in the isospin I=2 channel and the P-wave pion-pion\nscattering phase in the isospin I=1 channel. In the former channel, the lattice\ncalculations are performed at pion masses ranging from 270 MeV to 485 MeV. We\nuse chiral perturbation theory at next-to-leading order to extrapolate our\nresults. At the physical pion mass, we find m_pi a_pipi(I=2)=-0.04385(28)(38)\nfor the scattering length. In the latter channel, the calculation is currently\nperformed at a single pion mass of 391 MeV. Making use of finite size methods,\nwe evaluate the scattering phase in both the center of mass frame and the\nmoving frame. The effective range formula is employed to fit our results, from\nwhich the rho resonance mass and decay width are evaluated."
    },
    {
        "anchor": "Tensor Charge of the Nucleon in Lattice QCD: First results of lattice QCD simulation on the nucleon tensor-charge $\\delta\nq$ are presented. From the quenched QCD simulations with the Wilson quark\naction at $\\beta = 5.7$ on a 16$^3\\times$ 20 lattice and on a $12^3\\times 20$\nlattice, we find (i) the connected part $\\delta q_{con.}$ is determined with\nsmall statistical error, (ii) the disconnected part $\\delta q_{dis.}$, which\nviolates the OZI rule, is consistent with zero, and (iii) the flavor-singlet\ntensor charge $ \\delta \\Sigma (\\mu^2 = 2 {\\rm GeV}^2) = \\delta u + \\delta d +\n\\delta s$ takes 0.562(88) at $\\beta=5.7$, which is in contrast with the\nflavor-singlet axial charge $\\Delta \\Sigma = 0.1-0.3$.",
        "positive": "Towards selecting a finite-range regularization scale: Extensive studies have demonstrated that finite-range regularization (FRR)\noffers significantly improved chiral extrapolations for lattice QCD. These\nstudies have typically relied on selecting the finite-regularization scale\nbased upon phenomenological input. Here we report on a preliminary\ninvestigation of a procedure to determine a preferred range of FRR scale based\non nonperturbative lattice results -- without any phenomenological prejudice."
    },
    {
        "anchor": "Lattice QCD at non-zero temperature: I review our current understanding of the properties of strongly interacting\nmatter at high temperatures, based upon numerical calculations in lattice QCD.\nI discuss the chiral and deconfining aspects of the QCD transition, the\nequation of state, fluctuations of conserved charges, color screening, meson\ncorrelation functions, and the determination of some transport coefficients.",
        "positive": "Exploratory study of the D_s spectrum in 2+1 Domain Wall QCD with heavy\n  overlap: We present preliminary results for the D_s meson spectroscopy study on the\n2+1 flavour domain wall fermion lattice configurations, generated with the\nIwasaki gauge action at beta=2.13 by the RBC-UKQCD collaboration. The\nsimulations are on 16^3\\times32 lattice with L_s=16. We consider the charm\nquark propagating as an overlap fermion at fixed lattice spacing. The\ndispersion relation and mass splittings are evaluated."
    },
    {
        "anchor": "Twist free energy and critical behavior of 3D U(1) LGT at finite\n  temperature: The twist free energy is computed in the Villain formulation of the 3D U(1)\nlattice gauge theory at finite temperature. This enables us to obtain\nrenormalization group equations describing a critical behavior of the model in\nthe vicinity of the deconfinement phase transition. These equations are used to\ncheck the validity of the Svetitsky-Yaffe conjecture regarding the critical\nbehavior of the lattice U(1) model. In particular, we calculate the two-point\ncorrelation function of the Polyakov loops and determine some critical indices.",
        "positive": "Towards thermodynamics with $N_f=2+1+1$ twisted mass quarks: We present preliminary results achieved within a recently started project\ndealing with QCD thermodynamics in the presence of a fully dynamical second\nquark family. We are employing the Wilson twisted mass discretization. To\nreduce the amount of zero temperature simulations and the cost of analysis we\nhave chosen the fixed-scale approach. We show a variety of basic thermodynamic\nobservables for temperatures ranging from 158 to 633 MeV. Simulations were\nperformed for three lattice spacings below 0.1 fm each and at a single value of\nthe pion mass which allows a comparison with previously obtained $N_f=2$\nresults. We determine the chiral crossover temperature from the bare chiral\nsusceptibility and show results for the gauge part of the trace anomaly."
    },
    {
        "anchor": "Calculation and Interpretation of Hadron Correlation Functions in\n  Lattice QCD: Several new developments in the calculation and interpretation of hadron\ndensity-density correlation functions are presented. The asymptotic behavior of\ncorrelation functions is determined from a tree diagram path integral. A method\nis developed to use this behavior to correct for leading image contributions on\na finite periodic spatial lattice and to correct for the finite temporal extent\nof the lattice. Equal time correlation functions are shown to determine a sum\nof the ground state rms radius plus a polarization correction, and it is shown\nhow to extract the hadron polarizability from unequal time correlation\nfunctions. Image-corrected correlation functions calculated in quenched lattice\nQCD are presented and used to determine the size of the pion and nucleon.",
        "positive": "Dual Methods for Lattice Field Theories at Finite Density: We present a dual representation of the partition function of the charged\nscalar field in which the complex action problem at non-zero chemical potential\nis absent. In this dual representation Monte Carlo simulations are possible and\nwe show some physical results obtained with this approach. Furthermore we\npresent a technique to study 2-point functions at finite density. Results for\nthe lattice correlators at various chemical potentials are shown and discussed."
    },
    {
        "anchor": "Simulations of QCD and QED with C* boundary conditions: We present exploratory results from dynamical simulations of QCD in\nisolation, as well as QCD coupled to QED, with C* boundary conditions. In\nfinite volume, the use of C* boundary conditions allows for a gauge invariant\nand local formulation of QED without zero modes. In particular we show that the\nsimulations reproduce known results and that masses of charged mesons can be\nextracted in a completely gauge invariant way. For the simulations we use a\nmodified version of the HiRep code. The primary features of the simulation code\nare presented and we discuss some details regarding the implementation of C*\nboundary conditions and the simulated lattice action.",
        "positive": "Next to Leading Order Chiral Perturbation theory of $K \u03c0\\to \u03c0$ and\n  $K\\to\u03c0\u03c0$ amplitudes: It is shown that the low energy coefficients of the next-to-leading order\n(NLO) chiral perturbation theory needed to determine $\\Delta I=1/2$,\n$K\\to\\pi\\pi$ decay amplitudes can be fixed by calculating $K\\pi\\to\\pi$\namplitudes on lattice. Unlike using NLO $K\\to\\pi\\pi$ amplitudes proposed by\nLaiho and Soni, simulating $K\\pi\\to\\pi$ transitions on lattice does not require\nevaluations of s-channel disconnected diagrams which have been an obstacle in\npractice."
    },
    {
        "anchor": "The QCD phase diagram at zero and small baryon density: I review recent developments in determining the QCD phase diagram by means of\nlattice simulations. Since the invention of methods to side-step the sign\nproblem a few years ago, a number of additional variants have been proposed,\nand progress has been made towards understanding some of the systematics\ninvolved. All available techniques agree on the transition temperature as a\nfunction of density in the regime \\mu_q/T < 1. There are by now four\ncalculations with signals for a critical point, two of them at similar\nparameter values and with consistent results. However, it also emerges that the\nlocation of the critical point is exceedingly quark mass sensitive. At the same\ntime sizeable finite volume, cut-off and step size effects have been uncovered,\ndemanding additional investigations with exact algorithms on larger and finer\nlattices before quantitative conclusions can be drawn. Depending on the sign of\nthese corrections, there is ample room for the eventual phase diagram to look\nas expected or also quite different, with no critical point at all.",
        "positive": "The chiral phase transition for lattice QCD with 2 colour-sextet quarks: QCD with 2 flavours of massless colour-sextet quarks is studied as a possible\nwalking-Technicolor candidate. We simulate the lattice version of this model at\nfinite temperatures near to the chiral-symmetry restoration transition, to\ndetermine whether it is indeed a walking theory (QCD-like with a running\ncoupling which evolves slowly over an appreciable range of length scales) or if\nit has an infrared fixed point, making it a conformal field theory. The lattice\nspacing at this transition is decreased towards zero by increasing the number\n$N_t$ of lattice sites in the temporal direction. Our simulations are performed\nat $N_t=4,6,8,12$, on lattices with spatial extent much larger than the\ntemporal extent. A range of small fermion masses is chosen to make predictions\nfor the chiral (zero mass) limit. We find that the bare lattice coupling does\ndecrease as the lattice spacing is decreased. However, it decreases more slowly\nthan would be predicted by asymptotic freedom. We discuss whether this means\nthat the coupling is approaching a finite value as lattice $N_t$ is increased\n-- the conformal option, or if the apparent disagreement with the scaling\npredicted by asymptotic freedom is because the lattice coupling is a poor\nexpansion parameter, and the theory walks. Currently, evidence favours QCD with\n2 colour-sextet quarks being a conformal field theory. Other potential sources\nof disagreement with the walking hypothesis are also discussed.\n  We also report an estimate of the position of the deconfinement transition\nfor $N_t=12$, needed for choosing parameters for zero-temperature simulations."
    },
    {
        "anchor": "Confinement-Deconfinement transition and $Z_2$ symmetry in $Z_2+$Higgs\n  theory: We study the Polyakov loop and the $Z_2$ symmetry in the lattice $Z_2+$Higgs\ntheory in 4D Euclidean space using Monte Carlo simulations. The results show\nthat this symmetry is realised in the Higgs symmetric phase for large number of\ntemporal lattice sites. To understand the dependence on the number of temporal\nsites, we consider a one dimensional model by keeping terms of the original\naction corresponding to a single spatial site. In this approximation the\npartition function can be calculated exactly as a function of the Polyakov\nloop. The resulting free energy is found to have the $Z_2$ symmetry in the\nlimit of large temporal sites. We argue that this is due to $Z_2$ invariance as\nwell as dominance of the distribution or density of states corresponding to the\naction.",
        "positive": "One-Loop Hybrid Renormalization Matching Kernels for Quasi-Parton\n  Distributions: Large momentum effective theory allows extraction of hadron parton\ndistribution functions in lattice QCD by matching them to quark bilinear matrix\nelements of hadrons with large momenta. We calculate the matching kernels for\nthe unpolarized, helicity, and transversity isovector parton distribution\nfunctions and skewless generalized parton distributions of all hadrons in the\nhybrid-RI/MOM scheme. This renormalization scheme uses RI/MOM when the Wilson\nline length is less then $z_s$, otherwise a mass subtraction scheme is used. By\ndesign, the non-hybrid scheme is recovered as $z_s \\to \\infty$. In the opposite\nlimit, $z \\to 0$, the self renormalization scheme is obtained. When the\nparameters $p_z^R=0$ and $\\mu^R z_s \\ll 1$, the hybrid-RI/MOM scheme coincides\nwith the hybrid-ratio scheme times the charge of the PDF. We also discuss the\nsubtlety related to the commutativity of Fourier transform and $\\epsilon$\nexpansion in the $\\bar{\\text{MS}}$ scheme."
    },
    {
        "anchor": "Supersymmetry Breaking in Low Dimensional Models: We analyse supersymmetric models that show supersymmetry breaking in one and\ntwo dimensions using lattice methods. Starting from supersymmetric quantum\nmechanics we explain the fundamental principles and problems that arise in\nputting supersymmetric models onto the lattice. We compare our lattice results\n(built upon the non-local SLAC derivative) with numerically exact results\nobtained within the Hamiltonian approach. A particular emphasis is put on the\ndiscussion of boundary conditions. We investigate the ground state structure,\nmass spectrum, effective potential and Ward identities and conclude that\nlattice methods are suitable to derive the physical properties of\nsupersymmetric quantum mechanics, even with broken supersymmetry. Based on this\nresult we analyse the two dimensional N=1 Wess-Zumino model with spontaneous\nsupersymmetry breaking. First we show that (in agreement with earlier\nanalytical and numerical studies) the SLAC derivative is a sensible choice in\nthe quenched model, which is nothing but the two dimensional phi^4 model. Then,\nwe present the very first computation of a renormalised critical coupling for\nthe complete supersymmetric model. This calculation makes use of Binder\ncumulants and is supported by a direct comparison to Ward identity results,\nboth in the continuum and infinite volume limit. The physical picture is\ncompleted by masses at two selected couplings, one in the supersymmetric phase\nand one in the supersymmetry broken phase. Signatures of the Goldstino in the\nfermionic correlator are clearly visible in the broken case.",
        "positive": "Delta I=3/2 K to pi-pi decays with nearly physical kinematics: The \\Delta I = 3/2 K to pi pi decay amplitude is calculated on RBC/UKQCD 32^3\ntimes 64, L_s=32 dynamical lattices with 2+1 flavours of domain wall fermions\nusing the Dislocation Suppressing Determinant Ratio and Iwasaki gauge action.\nThe calculation is performed close to the physical pion mass (m_pi = 142.9(1.1)\nMeV and with a single lattice spacing (a^-1= 1.375(9) GeV.) We find Re(A_2) =\n(1.436 \\pm 0.063_{stat} \\pm 0.258_{syst}) times 10^-8 GeV and Im(A_2) = (-6.29\n\\pm 0.46_{stat} \\pm 1.20_{syst})\\times 10^{-13} GeV. These results are combined\nwith the experimental result for epsilon'/epsilon to predict Im(A_0) =\n-5.32(64)_{stat}(71)_{syst}\\times 10^{-11} GeV within the Standard Model. We\nalso perform a reweighting analysis to investigate the effects of partial\nquenching in the light-quark sector of our calculation. Following reweighting\nwe find Re(A_2) = (1.52\\pm 0.14_{stat}) \\times 10^-8 GeV and Im(A_2) = (-6.47\n\\pm 0.55_{stat})\\times 10^-13 GeV, which are consistent with our main results."
    },
    {
        "anchor": "Phase diagram of four-dimensional dynamical triangulations with a\n  boundary: We report on simulations of DT simplicial gravity for manifolds with the\ntopology of the 4-disk. We find evidence for four phases in a two-dimensional\nparameter space. In two of these the boundary plays no dynamical role and the\ngeometries are equivalent to those observed earlier for the sphere $S^4$. In\nanother phase the boundary is maximal and the quantum geometry degenerates to a\none dimensional branched polymer. In contrast we provide evidence that the\nfourth phase is effectively three-dimensional. We find discontinuous phase\ntransitions at all the phase boundaries.",
        "positive": "Diagrammatic Monte-Carlo for weak-coupling expansion of non-Abelian\n  lattice field theories: large-N U(N)xU(N) principal chiral model: We develop numerical tools for Diagrammatic Monte-Carlo simulations of\nnon-Abelian lattice field theories in the t'Hooft large-N limit based on the\nweak-coupling expansion. First we note that the path integral measure of such\ntheories contributes a bare mass term in the effective action which is\nproportional to the bare coupling constant. This mass term renders the\nperturbative expansion infrared-finite and allows to study it directly in the\nlarge-N and infinite-volume limits using the Diagrammatic Monte-Carlo approach.\nOn the exactly solvable example of a large-N O(N) sigma model in D=2 dimensions\nwe show that this infrared-finite weak-coupling expansion contains, in addition\nto powers of bare coupling, also powers of its logarithm, reminiscent of\nre-summed perturbation theory in thermal field theory and resurgent\ntrans-series without exponential terms. We numerically demonstrate the\nconvergence of these double series to the manifestly non-perturbative dynamical\nmass gap. We then develop a Diagrammatic Monte-Carlo algorithm for sampling\nplanar diagrams in the large-N matrix field theory, and apply it to study this\ninfrared-finite weak-coupling expansion for large-N U(N)xU(N) nonlinear sigma\nmodel (principal chiral model) in D=2. We sample up to 12 leading orders of the\nweak-coupling expansion, which is the practical limit set by the increasingly\nstrong sign problem at high orders. Comparing Diagrammatic Monte-Carlo with\nconventional Monte-Carlo simulations extrapolated to infinite N, we find a good\nagreement for the energy density as well as for the critical temperature of the\n\"deconfinement\" transition. Finally, we comment on the applicability of our\napproach to planar QCD at zero and finite density."
    },
    {
        "anchor": "Remark on lattice BRST invariance: A recently claimed resolution to the lattice Gribov problem in the context of\nchiral lattice gauge theories is examined. Unfortunately, I find that the old\nproblem remains.",
        "positive": "Asymptotic scaling and continuum limit of pure SU(3) lattice gauge\n  theory: Recently the Yang-Mills gradient flow of pure SU(3) lattice gauge theory has\nbeen calculated in the range from $\\beta=6/g_0^2=6.3$ to~7.5 (Asakawa et al.),\nwhere $g_0^2$ is the bare coupling constant of the SU(3) Wilson action.\nEstimates of the deconfining phase transition are available from $\\beta =5.7$\nto~6.8 (Francis et al.). Here it is shown that the entire range from 5.7 to 7.5\nis well described by a power series of the lattice spacing $a$ times the lambda\nlattice mass scale $\\Lambda_L$, using asymptotic scaling in the 2-loop and\n3-loop approximations for $a\\Lambda_L$. In both cases identical ratios for\ngradient flows versus deconfinement observables are obtained. Differences in\nthe normalization constants with respect to $\\Lambda_L$ give a handle on their\nsystematic errors."
    },
    {
        "anchor": "Glueball Spectrum and Matrix Elements on Anisotropic Lattices: The glueball-to-vacuum matrix elements of local gluonic operators in scalar,\ntensor, and pseudoscalar channels are investigated numerically on several\nanisotropic lattices with the spatial lattice spacing ranging from 0.1fm -\n0.2fm. These matrix elements are needed to predict the glueball branching\nratios in $J/\\psi$ radiative decays which will help identify the glueball\nstates in experiments. Two types of improved local gluonic operators are\nconstructed for a self-consistent check and the finite volume effects are\nstudied. We find that lattice spacing dependence of our results is very weak\nand the continuum limits are reliably extrapolated, as a result of improvement\nof the lattice gauge action and local operators. We also give updated glueball\nmasses with various quantum numbers.",
        "positive": "Exploring Three-Nucleon Forces in Lattice QCD: Three-nucleon forces (3NF) are investigated from two-flavor lattice QCD\nsimulations. We utilize the Nambu-Bethe-Salpeter (NBS) wave function to\ndetermine two-nucleon forces (2NF) and 3NF in the same framework. As a first\nexploratory study, we extract 3NF in which three nucleons are aligned linearly\nwith an equal spacing. This is the simplest geometrical configuration which\nreduces the huge computational cost of calculating the NBS wave function.\nQuantum numbers of the three-nucleon system are chosen to be (I,\nJ^P)=(1/2,1/2^+) (the triton channel). Lattice QCD simulations are performed\nusing N_f=2 dynamical clover fermion configurations at the lattice spacing of a\n= 0.156 fm on a 16^3 x 32 lattice with a large quark mass corresponding to\nm_\\pi= 1.13 GeV. We find repulsive 3NF at short distance in the triton channel.\nSeveral sources of systematic errors are also discussed."
    },
    {
        "anchor": "A New Approach to Spin Glass Simulations: We present a recursive procedure to calculate the parameters of the recently\nintroduced multicanonical ensemble and explore the approach for spin glasses.\nTemperature dependence of the energy, the entropy and other physical quantities\nare easily calculable and we report results for the zero temperature limit. Our\ndata provide evidence that the large $L$ increase of the ergodicity time is\ngreatly improved. The multicanonical ensemble seems to open new horizons for\nsimulations of spin glasses and other systems which have to cope with\nconflicting constraints.",
        "positive": "Exploring Models for New Physics on the Lattice: Strongly-coupled gauge theories are an important ingredient in the\nconstruction of many extensions of the standard model, particularly for models\nof electroweak symmetry breaking in which the Higgs boson is a composite\nobject. There is a large parameter space of such gauge theories with a rich\nphase structure, particularly in the presence of large numbers of fermionic\ndegrees of freedom. Lattice simulation provides a non-perturbative way to\nexplore this space of strongly-coupled theories, and to search for interesting\ndynamical features. Here I review recent progress in the simulation of such\ntheories, with an eye towards applications to dynamical electroweak symmetry\nbreaking."
    },
    {
        "anchor": "Nucleon-nucleon scattering from distillation: We report an ongoing analysis of nucleon-nucleon scattering based on\nfinite-volume spectroscopy. The calculation is performed using the distillation\nmethod on eight lattice ensembles at the SU(3)-symmetric point with\n$m_\\pi=m_K\\approx 420$ MeV generated by CLS, covering a range of lattice\nspacings and volumes and previously used to study the $H$ dibaryon. We obtain\nnonzero signals for $S$, $P$, $D$, and $F$ waves as well as the mixing between\nspin-1 $S$ and $D$ waves. For $S$ waves, lattice artifacts are significant and\ntend to strengthen baryon-baryon interactions. In the deuteron and dineutron\n$S$ waves, we find virtual bound states.",
        "positive": "Exact Large-Nc Solution of an Effective Theory for Polyakov Loops at\n  Finite Chemical Potential: Using the strong coupling expansion we calculate the analytically exact order\nparameter for the effective theory of Polyakov loops with applied chemical\npotential in the large-Nc limit."
    },
    {
        "anchor": "Real space renormalization group for twisted lattice N=4 super\n  Yang-Mills: A necessary ingredient for our previous results on the form of the long\ndistance effective action of the twisted lattice N=4 super Yang-Mills theory is\nthe existence of a real space renormalization group which preserves the lattice\nstructure, both the symmetries and the geometric interpretation of the fields.\nIn this brief article we provide an explicit example of such a blocking scheme\nand illustrate its practicality in the context of a small scale Monte Carlo\nrenormalization group calculation. We also discuss the implications of this\nresult, and the possible ways in which to use it in order to obtain further\ninformation about the long distance theory.",
        "positive": "Testing the holographic principle using lattice simulations: The lattice studies of maximally supersymmetric Yang-Mills (MSYM) theory at\nstrong coupling and large N is important for verifying gauge/gravity duality.\nDue to the progress made in the last decade, based on ideas from topological\ntwisting and orbifolding, it is now possible to study these theories on the\nlattice while preserving an exact supersymmetry on the lattice. We present some\nresults from the lattice studies of two-dimensional MSYM which is related to\nType II supergravity. Our results agree with the thermodynamics of different\nblack hole phases on the gravity side and the phase transition\n(Gregory--Laflamme) between them."
    },
    {
        "anchor": "Sampling U(1) gauge theory using a re-trainable conditional flow-based\n  model: Sampling topological quantities in the Monte Carlo simulation of Lattice\nGauge Theory becomes challenging as we approach the continuum limit of the\ntheory. In this work, we introduce a Conditional Normalizing Flow (C-NF) model\nto sample U(1) gauge theory in two dimensions, aiming to mitigate the impact of\ntopological freezing when dealing with smaller values of the U(1) bare\ncoupling. To train the conditional flow model, we utilize samples generated by\nHybrid Monte Carlo (HMC) method, ensuring that the autocorrelation in\ntopological quantities remains low. Subsequently, we employ the trained model\nto interpolate the coupling parameter to values where training was not\nperformed. We thoroughly examine the quality of the model in this region and\ngenerate uncorrelated samples, significantly reducing the occurrence of\ntopological freezing. Furthermore, we propose a re-trainable approach that\nutilizes the model's own samples to enhance the generalization capability of\nthe conditional model. This method enables sampling for coupling values that\nare far beyond the initial training region, expanding the applicability of the\nmodel.",
        "positive": "Skewness and kurtosis of net baryon-number distributions at small values\n  of the baryon chemical potential: We present results for the ratios of mean ($M_B$), variance ($\\sigma_B^2$),\nskewness ($S_B)$ and kurtosis ($\\kappa_B$) of net baryon-number fluctuations\nobtained in lattice QCD calculations with a physical light to strange quark\nmass ratio. Using next-to-leading order Taylor expansions in baryon chemical\npotential we find that qualitative features of these ratios closely resemble\nthe corresponding experimentally measured cumulants ratios of net proton-number\nfluctuations for beam energies down to $\\sqrt{s_{_{NN}}} \\ge 19.6$ GeV. We show\nthat the difference in cumulant ratios for the mean net baryon-number,\n$M_B/\\sigma_B^2=\\chi_1^B(T,\\mu_B)/\\chi_2^B(T,\\mu_B)$ and the normalized\nskewness, $S_B\\sigma_B=\\chi_3^B(T,\\mu_B)/\\chi_2^B(T,\\mu_B)$, naturally arises\nin QCD thermodynamics. Moreover, we establish a close relation between skewness\nand kurtosis ratios, $S_B\\sigma_B^3/M_B=\\chi_3^B(T,\\mu_B)/\\chi_1^B(T,\\mu_B)$\nand $\\kappa_B\\sigma_B^2=\\chi_4^B(T,\\mu_B)/\\chi_2^B(T,\\mu_B)$, valid at small\nvalues of the baryon chemical potential."
    },
    {
        "anchor": "Confining Configurations in QCD and Relation to Rigid Strings: The gauge field configurations of QCD gauge fields in the infrared regime are\nobtained by magnetic symmetry condition. The effective dual action exhibits\ndual Meissner effect with quarks included. A string representation of this\naction corresponds to rigid string.",
        "positive": "Lattice fermions as spectral graphs: We study lattice fermions from the viewpoint of spectral graph theory (SGT).\nWe find that a fermion defined on a certain lattice is identified as a spectral\ngraph. SGT helps us investigate the number of zero eigenvalues of lattice Dirac\noperators even on the non-torus and non-regular lattice, leading to\nunderstanding of the number of fermion species (doublers) on lattices with\narbitrary topologies. The procedure of application of SGT to lattice fermions\nis summarized as follows: (1) One investigates a spectral graph corresponding\nto a lattice fermion. (2) One obtains a matrix corresponding to the graph. (3)\nOne finds zero eigenvalues of the matrix by use of the discrete Fourier\ntransformation (DFT). (4) By taking an infinite-volume and continuum limits,\none finds the number of species. We apply this procedure to the known lattice\nfermion formulations including Naive fermions, Wilson fermions and Domain-wall\nfermions, and reproduce the known fact on the number of species. We also apply\nit to the lattice fermion on the discretized four-dimensional hyperball and\ndiscuss the number of fermion species on the bulk. In the end of the paper, we\ndiscuss the application of the analysis to lattice fermions on generic lattices\nwith arbitrary topologies, which could lead to constructing a new theorem\nregarding the number of species."
    },
    {
        "anchor": "Supersymetry on the Noncommutative Lattice: Built upon the proposal of Kaplan et.al. [hep-lat/0206109], we construct\nnoncommutative lattice gauge theory with manifest supersymmetry. We show that\nsuch theory is naturally implementable via orbifold conditions generalizing\nthose used by Kaplan {\\sl et.al.} We present the prescription in detail and\nillustrate it for noncommutative gauge theories latticized partially in two\ndimensions. We point out a deformation freedom in the defining theory by a\ncomplex-parameter, reminiscent of discrete torsion in string theory. We show\nthat, in the continuum limit, the supersymmetry is enhanced only at a\nparticular value of the deformation parameter, determined solely by the size of\nthe noncommutativity.",
        "positive": "Novel phase in SU(3) lattice gauge theory with 12 light fermions: We study the phase structure of SU(3) lattice gauge theory with Nf=12\nstaggered fermions in the fundamental representation, for both zero and finite\ntemperature at strong gauge couplings. For small fermion masses we find two\ntransitions at finite temperature that converge to two well-separated bulk\nphase transitions. The phase between the two transitions appears to be a novel\nphase. We identify order parameters showing that the single-site shift symmetry\nof staggered fermions is spontaneously broken in this phase. We investigate the\neigenvalue spectrum of the Dirac operator, the static potential and the meson\nspectrum, which collectively establish that this novel phase is confining but\nchirally symmetric. The phase is bordered by first-order phase transitions, and\nsince we find the same phase structure with Nf=8 fermions, we argue that the\nnovel phase is most likely a strong-coupling lattice artifact, the existence of\nwhich does not imply IR conformality."
    },
    {
        "anchor": "Recombination of dyons into calorons in SU(2) lattice fields at low\n  temperatures: By cooling of equilibrium lattice fields at finite temperature in SU(2) gauge\ntheory it has been shown that topological objects (calorons) observed on the\nlattice in the confined phase possess a dyonic substructure which becomes\nvisible under certain circumstances. Here we show that, with decreasing\ntemperature of the equilibrium ensemble, the distribution in the caloron\nparameter space is modified such that the calorons appear non-dissociated into\nconstituent dyons. Still the calorons have nontrivial holonomy which is\ndemonstrated by the Polyakov line behaviour for these configurations. At\nvanishing temperature (on a symmetric lattice) topological lumps obtained by\ncooling possess rotational symmetry in 4D and a characteristic double peak\nstructure of Polyakov lines (defined with respect to temporal and spatial\ndirections) with non-trivial asymptotics.",
        "positive": "$N\u03c0$-state contamination in lattice calculations of the nucleon\n  pseudoscalar form factor: The nucleon-pion-state contribution in the QCD 3-point function of the\npseudoscalar density is calculated to leading order in chiral perturbation\ntheory. It predicts a nucleon-pion-state contamination in lattice estimates for\nthe pseudoscalar form factor $G_{\\rm P}(Q^2)$ determined with the plateau\nmethod. Depending on the momentum transfer $Q^2$ the contamination varies\nbetween -20% and +50% for a source-sink separation of 2 fm. The\nnucleon-pion-state contamination also causes violations in the generalized\nGoldberger-Treiman relation among the pseudoscalar and the axial nucleon form\nfactors, the dominant source being the nucleon-pion-state contamination in the\ninduced pseudoscalar form factor $\\tilde{G}_{\\rm P}(Q^2)$. Comparing the chiral\nperturbation theory predictions with lattice results of the PACS collaboration\nwe find reasonable agreement even for source-sink separations as small as 1.3\nfm."
    },
    {
        "anchor": "Power Counting Regime of Chiral Effective Field Theory and Beyond: Chiral effective field theory complements numerical simulations of quantum\nchromodynamics (QCD) on a space-time lattice. It provides a model-independent\nformalism for connecting lattice simulation results at finite volume and a\nvariety of quark masses to the physical world. The asymptotic nature of the\nchiral expansion places the focus on the first few terms of the expansion.\nThus, knowledge of the power-counting regime (PCR) of chiral effective field\ntheory, where higher-order terms of the expansion may be regarded as\nnegligible, is as important as knowledge of the expansion itself. Through the\nconsideration of a variety of renormalization schemes and associated\nparameters, techniques to identify the PCR where results are independent of the\nrenormalization scheme are established. The nucleon mass is considered as a\nbenchmark for illustrating this general approach. Because the PCR is small, the\nnumerical simulation results are also examined to search for the possible\npresence of an intrinsic scale which may be used in a nonperturbative manner to\ndescribe lattice simulation results outside of the PCR. Positive results that\nimprove on the current optimistic application of chiral perturbation theory\nbeyond the PCR are reported.",
        "positive": "The QCD chiral phase transition for different numbers of quark flavours: We present results from a comprehensive study of the location of the chiral\ncritical surface, which separates regions of first-order chiral transitions\nfrom analytic crossovers, in the bare parameter space of lattice QCD with\nunimproved staggered fermions. We study the theories with $N_f\\in[2,8]$ and\ntrace the chiral critical surface along diminishing lattice spacing, with\n$N_\\tau=\\{4,6,8\\}$. This allows for an extrapolation to the lattice chiral\nlimit, where the surface has to terminate in a tricritical line, employing\nknown tricritical scaling relations. Knowing the phase structure in the lattice\nbare parameter space allows to draw conclusions for the approach to the\ncontinuum and chiral limits taken in the appropriate order. Our data provide\nevidence for the continuum chiral limit to feature a second-order transition\nfor all $N_f\\in[2,7]$. We perform an analogous scaling analysis with already\npublished data from $N_f=3$ $O(a)$-improved Wilson fermions, which is also\nconsistent with a second-order transition in the continuum. A modified Columbia\nplot reflecting those results is suggested."
    },
    {
        "anchor": "New perspectives on the emergence of (3+1)D expanding space-time in the\n  Lorentzian type IIB matrix model: The type IIB matrix model is a promising candidate for a nonperturbative\nformulation of superstring theory. In the Lorentzian version, in particular,\nthe emergence of (3+1)D expanding space-time was observed by Monte Carlo\nstudies of this model. Here we provide new perspectives on the (3+1)D expanding\nspace-time that have arised from recent studies. First it was found that the\nmatrix configurations generated by the simulation are singular in that the\nsubmatrices representing the expanding 3D space have only two large eigenvalues\nassociated with the Pauli matrices. This problem was conjectured to occur due\nto the approximation used to avoid the sign problem in simulating the model. In\norder to confirm this conjecture, the complex Langevin method was applied to\novercome the sign problem instead of using the approximation. The results\nindeed showed a clear departure from the Pauli-matrix structure, while the\n(3+1)D expanding behavior remained unaltered. It was also found that classical\nsolutions obtained within a certain ansatz show quite generically a (3+1)D\nexpanding behavior with smooth space-time structure.",
        "positive": "Glueballs in $N_f=1$ QCD: We present an evaluation of the glueball spectrum for configurations produced\nwith $N_f=1$ dynamical fermions as a function of the $m_{\\rm PCAC}$ mass. We\nobtained masses of states that fall into the irreducible representations of the\noctahedral group of rotations in combination with the quantum numbers of charge\nconjugation $C$ and parity $P$. Due to the low signal to noise ratio,\npractically, we can only extract masses for the irreducible representations\n$R^{PC}=$ $A_1^{++}$, $E^{++}$, $T_2^{++}$ as well as $A_1^{-+}$. We make use\nof the Generalized Eigenvalue Problem (GEVP) with an operator basis consisting\nonly of gluonic operators. Throughout this work we are aiming towards the\nidentification of the effects of light dynamical quarks on the glueball\nspectrum and how this compares to the statistically more precise spectrum of\nSU(3) pure gauge theory. We used large gauge ensembles which consist of ${\\sim\n{~\\cal O}}(10 {\\rm K})$ configurations. Our findings demonstrate that the\nlow-lying spectrum of the scalar, tensor as well as pseudo-scalar glueballs\nreceive negligible contributions from the inclusion of $N_f=1$ dynamical\nfermions."
    },
    {
        "anchor": "Walking in the 3-dimensional large $N$ scalar model: The solvability of the three-dimensional O($N$) scalar field theory in the\nlarge $N$ limit makes it an ideal toy model exhibiting \"walking\" behavior,\nexpected in some SU($N$) gauge theories with a large number of fermion flavors.\nWe study the model using lattice regularization and show that when the ratio of\nthe particle mass to an effective 4-point coupling (with dimension mass) is\nsmall, the beta function associated to the running 4-point coupling is\n\"walking\". We also study lattice artifacts and finite size effects, and find\nthat while the former can be sizable at realistic correlation length, the\nlatter are under control already at lattice sizes a few ($\\sim$3) correlation\nlengths. We show the robustness of the walking phenomenon by showing that it\ncan also be observed by studying physical observables such as the scattering\nphase shifts and the mass gap in finite volume.",
        "positive": "Static and non-static vector screening masses: Thermal screening masses of the conserved vector current are calculated both\nin a weak-coupling approach and in lattice QCD. The inverse of a screening mass\ncan be understood as the length scale over which an external electric field is\nscreened in a QCD medium. The comparison of screening masses both in the zero\nand non-zero Matsubara frequency sectors shows good agreement of the\nperturbative and the lattice results. Moreover, at $T\\approx 508\\mathrm{MeV}$\nthe lightest screening mass lies above the free result ($2\\pi T$), in agreement\nwith the $\\mathcal{O}(g^2)$ weak-coupling prediction."
    },
    {
        "anchor": "Lattice QCD study for stringy excitation and role of UV gluons: In both cases of quark-antiquark (Q-Qbar) and three-quark (3Q) systems, we\nstudy ground-state and low-lying excited-state potentials in terms of the\ngluon-momentum component in the Coulomb gauge in SU(3) quenched lattice QCD. By\nintroducing UV-cut in the gluon-momentum space, we investigate the \"UV-gluon\nsensitivity\" of the ground-state and excited-state potentials quantitatively.\nSuch a non-quark-origin excitation is a purely gluonic excitation, which can be\ninterpreted as a stringy excitation in the color flux-tube picture of hadrons.\nFor both Q-Qbar and 3Q systems, the IR part of the ground-state potential is\nalmost unchanged, even after cutting off high-momentum gluon component. On the\nother hand, we find more significant change of excited-state potential by the\ncut of UV-gluons. However, even after the removal of UV-gluons, the magnitude\nof the low-lying gluonic excitation remains to be of the order of 1GeV.",
        "positive": "Landau levels in QCD: We present first evidence for the Landau level structure of Dirac eigenmodes\nin full QCD for nonzero background magnetic fields, based on first principles\nlattice simulations using staggered quarks. Our approach involves the\nidentification of the lowest Landau level modes in two dimensions, where\ntopological arguments ensure a clear separation of these modes from\nenergetically higher states, and an expansion of the full four-dimensional\nmodes in the basis of these two-dimensional states. We evaluate various\nfermionic observables including the quark condensate and the spin polarization\nin this basis to find how much the lowest Landau level contributes to them. The\nresults allow for a deeper insight into the dynamics of quarks and gluons in\nbackground magnetic fields and may be directly compared to low-energy models of\nQCD employing the lowest Landau level approximation."
    },
    {
        "anchor": "Banks-Casher-type relation for the BCS gap at high density: We derive a new Banks-Casher-type relation which relates the density of\ncomplex Dirac eigenvalues at the origin to the BCS gap of quarks at high\ndensity. Our relation is applicable to QCD and QCD-like theories without a sign\nproblem, such as two-color QCD and adjoint QCD with baryon chemical potential,\nand QCD with isospin chemical potential. It provides us with a method to\nmeasure the BCS gap through the Dirac spectrum on the lattice.",
        "positive": "Calculation of the N to Delta electromagnetic transition matrix element: We present results on the ratio of electric quadrupole to magnetic dipole\namplitudes, $R_{EM}={\\cal G}_{E2}/{\\cal G}_{M1}$, for the transition $\\gamma N\nto \\Delta$ from lattice QCD. We consider both the quenched and the 2-flavor\ntheory."
    },
    {
        "anchor": "The QCD Dirac Operator Spectrum and Finite-Volume Scaling: Random matrix theory and chiral Lagrangians offer a convenient tool for the\nexact calculation of microscopic spectral correlators of the Dirac operator in\na well-defined finite-volume scaling regime.",
        "positive": "The Euclidean two-point correlation function of the topological charge\n  density: We study the Euclidean two-point correlation function $G_q(x)$ of the\ntopological charge density in QCD. A general statement based on reflection\npositivity tells us that $G_q(x)<0$ for $x\\neq 0 $. On the other hand the\ntopological susceptibility $\\chi_q=\\int d^d x G_q(x)$ is a positive quantity.\nThis indicates that $G_q(x)$ developes a positive contact term at $x=0$, that\ncontributes to the determination of the physical value of $\\chi_q$. We show\nexplicitly these features of $G_q(x)$ in a solvable nontrivial continuum model,\nthe two-dimensional $CP^{N-1}$ model in the large-N limit. A similar analysis\nis done on the lattice."
    },
    {
        "anchor": "A novel method for the determination of hadron excited states in Lattice\n  QCD applied to the nucleon: A novel method for the precise identification and determination of the\nenergies that contribute in the spectral decomposition of lattice correlators\nis presented. The method is based on statistical concepts and it relies heavily\non simulation techniques.\n  The $\\eta_c$ correlator is analyzed within this method and the results\nobtained are compared to a previous analysis based on Bayesian statistics.\n  An analysis of the nucleon local two-point correlators leads to the\nidentification of the excited states in the positive and negative channels. A\ndiscussion on the Roper is included.",
        "positive": "A new approach to the study of effective string corrections in LGTs: We propose a new approach to the study of the interquark potential in Lattice\nGauge Theories. Instead of looking at the expectation value of Polyakov loop\ncorrelators we study the modifications induced in the chromoelectric flux by\nthe presence of the Polyakov loops. In abelian LGTs, thanks to duality, this\nstudy can be performed in a very efficient way, allowing to reach high\nprecision at a reasonable CPU cost. The major advantage of this strategy is\nthat it allows to eliminate the dominant effective string correction to the\ninterquark potential (the Luscher term) thus giving an unique opportunity to\ntest higher order corrections. Performing a set of simulations in the 3d gauge\nIsing model we were thus able to precisely identify and measure both the\nquartic and the sextic effective string corrections to the interquark\npotential. While the quartic term perfectly agrees with the Nambu-Goto one the\nsextic term is definitely different. Our result seems to disagree with the\nrecent proof of the universality of the sextic correction. We discuss a few\npossible explanations of this disagreement."
    },
    {
        "anchor": "Phase diagram of the 4D U(1) model at finite temperature: We explore the phase diagram of the 4D compact U(1) gauge theory at finite\ntemperature as a function of the gauge coupling and of the compactified\nEuclidean time dimension L_t. We show that the strong-to-weak coupling\ntransition, which is first order at T=0 (L_t=\\infty), becomes second order for\nhigh temperatures, i.e. for small values of L_t, with a tricritical temporal\nsize \\bar{L_t} located between 5 and 6. The critical behavior around the\ntricritical point explains and reconciles previous contradictory evidences\nfound in the literature.",
        "positive": "Matching of heavy-light flavour currents between HQET at order 1/m and\n  QCD: I. Strategy and tree-level study: We present a strategy how to match the full set of components of the\nheavy-light axial and vector currents in Heavy Quark Effective Theory (HQET),\nup to and including 1/m-corrections, to QCD. While the ultimate goal is to\napply these matching conditions non-perturbatively, in this study we first have\nimplemented them at tree-level, in order to find good choices of the matching\nobservables with small O(1/m^2) contributions. They can later be employed in\nthe non-perturbative matching procedure which is a crucial part of precision\nHQET computations of semileptonic decay form factors in lattice QCD."
    },
    {
        "anchor": "Some new results in O(a) improved lattice QCD: It is shown how on-shell O(a) improvement can be implemented\nnon-perturbatively in lattice QCD with Wilson quarks. Improvement conditions\nare obtained by requiring the PCAC relation to hold exactly in certain matrix\nelements. These are derived from the QCD Schr\\\"odinger functional which enables\nus to simulate directly at vanishing quark masses. In the quenched\napproximation and for bare couplings in the range $0\\leq g_0\\leq 1$, we\ndetermine the improved action, the improved axial current, the additive\nrenormalization of the quark mass and the isospin current normalization\nconstants Z_A and Z_V.",
        "positive": "Comment on \"The two-phase issue in the O(n) non-linear sigma-model: a\n  Monte-Carlo study\" by B.Alles, A.Buonanno and G.Cella: We comment on the recent paper by Alles et al (hep-lat/9608002)"
    },
    {
        "anchor": "Heavy-light meson in anisotropic lattice QCD: We examine whether the $O(a)$ improved quark action on anisotropic lattices\ncan be used as a framework for the heavy quark, which enables precision\ncomputation of matrix elements of heavy-light mesons. To this end, it is\ncrucial to verify that a mass independent and nonperturbative tuning of the\nparameters is possible. As a first step, we observe the dispersion relation of\nheavy-light mesons on a quenched lattice using the action which is\nnonperturbatively tuned only for the leading terms. On a lattice with the\nspatial cutoff $a_\\sigma^{-1} \\simeq$ 1.6 GeV and the anisotropy $\\xi=4$, the\nrelativity relation holds within 2% accuracy in the quark mass region $a_\\sigma\nm_Q \\leq 1.2$ with the bare anisotropy parameter tuned for the massless quark.\nWe also apply the action to a calculation of heavy-light decay constants in the\ncharm quark mass region.",
        "positive": "Heavy Quark Free Energies and Screening in SU(2) Gauge Theory: We investigate the singlet, triplet and colour average heavy quark free\nenergies in SU(2) pure gauge theory at various temperatures T. We focus on the\nlong distance behaviour of the free energies, studying in particular the\ntemperature dependence of the string tension and the screening masses. The\nresults are qualitatively similar to the SU(3) scenario, except near the\ncritical temperature Tc of the deconfining transition. Finally we test a\nrecently proposed method to renormalize the Polyakov loop."
    },
    {
        "anchor": "Direct Proof of Reflection Positivity of Free Overlap Dirac Fermion: It is shown that free lattice Dirac fermions defined by overlap Dirac\noperator fulfill the Osterwalder-Schrader reflection positivity condition with\nrespect to the link-reflection.",
        "positive": "Light Quark Simulations With FLIC Fermions: Hadron masses are calculated in quenched lattice QCD in order to probe the\nscaling behavior of a novel fat-link clover fermion action in which only the\nirrelevant operators of the fermion action are constructed using APE-smeared\nlinks. Light quark masses corresponding to an m_pi / m_rho ratio of 0.35 are\nconsidered to assess the exceptional configuration problem of clover-fermion\nactions. This Fat-Link Irrelevant Clover (FLIC) fermion action provides scaling\nwhich is superior to mean-field improvement and offers advantages over\nnonperturbative improvement, including reduced exceptional configurations."
    },
    {
        "anchor": "Microscopic Dirac Spectrum in a 2d Gauge Theory with Zero Chiral\n  Condensate: Fermionic theories with a vanishing chiral condensate (in the chiral limit)\nhave recently attracted considerable interest; in particular variants of\nmulti-flavour QCD are candidates for this behaviour. Here we consider the\n2-flavour Schwinger model as a simple theory with this property. Based on\nsimulations with light dynamical overlap fermions, we test the hypothesis that\nin such models the low lying Dirac eigenvalues could be decorrelated. That has\nbeen observed in 4d Yang-Mills theories at high temperature, but it cannot be\nconfirmed for the 2-flavour Schwinger model. We also discuss subtleties in the\nevaluation of the mass anomalous dimension and its IR extrapolation.",
        "positive": "Curvature and scaling in 4D dynamical triangulation: We study the average number of simplices $N'(r)$ at geodesic distance $r$ in\nthe dynamical triangulation model of euclidean quantum gravity in four\ndimensions. We use $N'(r)$ to explore definitions of curvature and of effective\nglobal dimension. An effective curvature $R_V$ goes from negative values for\nlow $\\kappa_2$ (the inverse bare Newton constant) to slightly positive values\naround the transition $\\kappa_2^c$. Far above the transition $R_V$ is hard to\ncompute. This $R_V$ depends on the distance scale involved and we therefore\ninvestigate a similar explicitly $r$ dependent `running' curvature $R_{\\rm\neff}(r)$. This increases from values of order $R_V$ at intermediate distances\nto very high values at short distances. A global dimension $d$ goes from high\nvalues in the region with low $\\kappa_2$ to $d=2$ at high $\\kappa_2$. At the\ntransition $d$ is consistent with 4. We present evidence for scaling of $N'(r)$\nand introduce a scaling dimension $d_s$ which turns out to be approximately 4\nin both weak and strong coupling regions. We discuss possible implications of\nthe results, the emergence of classical euclidean spacetime and a possible\n`triviality' of the theory."
    },
    {
        "anchor": "Exact Chiral Symmetry on the Lattice: QCD Applications: I review recent progress and results in lattice QCD obtained using fermions\nwith exact chiral symmetry.",
        "positive": "Scale setting in lattice QCD: The principles of scale setting in lattice QCD as well as the advantages and\ndisadvantages of various commonly used scales are discussed. After listing\ncriteria for good scales, I concentrate on the main presently used ones with an\nemphasis on scales derived from the Yang-Mills gradient flow. For these I\ndiscuss discretisation errors, statistical precision and mass effects. A short\nreview on numerical results also brings me to an unpleasant disagreement which\nremains to be explained."
    },
    {
        "anchor": "Mean field approximation for effective theories of lattice QCD: For the exploration of the phase diagram of QCD, effective Polyakov loop\ntheories derived from lattice QCD provide a valuable tool in the heavy quark\nmass regime. In practice, the evaluation of these theories is complicated by\nthe appearance of long-range and multipoint interaction terms. On the other\nhand, it is well known that for theories with such kind of interactions mean\nfield approximations can be expected to yield reliable results. Here, we apply\nthis framework to the critical endpoint of the deconfinement transition and\nresults are compared to the literature. This treatment can also be used to\ninvestigate the phase diagram at non-zero baryon and isospin chemical\npotential.",
        "positive": "Cooling in QCD Spectroscopy: We test the cooling algorithm with gluonic and staggered hadronic\nspectroscopy on $SU(3)$ gauge field configurations generated with two flavors\nof staggered dynamical fermions. We find cooling is not reliable as the basis\nfor improved hadronic operators. We also find that performing cooling sweeps to\nreveal more clearly the topological properties of the gauge fields eliminates\nthe spin structure of the hadron spectrum."
    },
    {
        "anchor": "Spin Correlations and Velocity-Scaling in NRQCD Matrix Elements: We compute spin-dependent matrix elements for decays of S-wave quarkonia in\nlattice NRQCD. They appear to be in approximate agreement with the\nvelocity-scaling rules of NRQCD.",
        "positive": "Decoupling of Layers in the Three-dimensional Abelian Higgs Model: The Abelian Higgs model with anisotropic couplings in 2+1 dimensions is\nstudied in both the compact and non-compact formulations. Decoupling of the\nspace-like planes takes place in the extreme anisotropic limit, so charged\nparticles and gauge fields are presumably localized within these planes. The\nbehaviour of the model under the influence of an external magnetic field is\nexamined in the compact case and yields further characterization of the phases."
    },
    {
        "anchor": "Long-distance Contributions to Neutrinoless Double Beta Decay $\u03c0^-\n  \\to\u03c0^+ e e$: Neutrinoless double beta decay, if detected, would prove that neutrinos are\nMajorana fermions and provide the direct evidence for lepton number violation.\nIf such decay would exist in nature, then $\\pi^-\\pi^-\\to ee$ and $\\pi^-\\to\\pi^+\nee$ (or equivalently $\\pi^-e^+\\to\\pi^+ e^-$) are the two simplest processes\naccessible via first-principle lattice QCD calculations. In this work, we\ncalculate the long-distance contributions to the $\\pi^-\\to\\pi^+ee$ transition\namplitude using four ensembles at the physical pion mass with various volumes\nand lattice spacings. We adopt the infinite-volume reconstruction method to\ncontrol the finite-volume effects arising from the (almost) massless neutrino.\nProviding the lattice QCD inputs for chiral perturbation theory, we obtain the\nlow energy constant\n$g_\\nu^{\\pi\\pi}(m_\\rho)=-10.89(28)_\\text{stat}(74)_\\text{sys}$, which is close\nto $g_\\nu^{\\pi\\pi}(m_\\rho)=-11.96(31)_\\text{stat}$ determined from the\ncrossed-channel $\\pi^-\\pi^-\\to ee$ decay.",
        "positive": "Non-perturbative calculation of Z_m using Asqtad fermions: We report progress on a non-perturbative calculation of the light quark mass\nrenormalization factor Z_m, using dynamical Asqtad fermions. This quantity is\nused to determine the light quark masses in the conventional MS-bar scheme.\nSuch a non-perturbative determination of Z_m removes uncertainties due to\ntruncation of its perturbative expansion, currently known to two loops. These\ncalculations have been carried out using publicly available MILC lattices with\nspacings of approximately 0.125 and 0.09 fm."
    },
    {
        "anchor": "Lattice study on kaon pion scattering length in the $I=3/2$ channel: Using the tadpole improved Wilson quark action on small, coarse and\nanisotropic lattices, $K\\pi$ scattering length in the $I=3/2$ channel is\ncalculated within quenched approximation. The results are extrapolated towards\nthe chiral and physical kaon mass region. Finite volume and finite lattice\nspacing errors are also analyzed and a result in the infinite volume and\ncontinuum limit is obtained. Our result is compared with the results obtained\nusing Roy equations, Chiral Perturbation Theory, dispersion relations and the\nexperimental data.",
        "positive": "String breaking on a lattice: String breaking is a non-perturbative long-distance feature of QCD that is\ninvolved in for example meson decays. A mixing analysis of lattice operators at\nzero temperature gives the level splitting and mixing energy between the broken\nand unbroken string states."
    },
    {
        "anchor": "Lattice Hamiltonian approach to the massless Schwinger model: precise\n  extraction of the mass gap: We present results of applying the Hamiltonian approach to the massless\nSchwinger model. A finite basis is constructed using the strong coupling\nexpansion to a very high order. Using exact diagonalization, the continuum\nlimit can be reliably approached. This allows to reproduce the analytical\nresults for the ground state energy, as well as the vector and scalar mass gaps\nto an outstanding precision better than 10^{-6} %.",
        "positive": "Hubbard Model and Luscher fermions: We discuss numerical complexity of the L\\\"uscher algorithm applied to the\nHubbard Model. In particular we present comparison to a certain algorithm based\non direct computation of the fermionic determinant."
    },
    {
        "anchor": "On Dirac Zero Modes in Hyperdiamond Model: Using the SU(5) symmetry of the 4D hyperdiamond and results on the study of\n4D graphene given in \"Four Dimensional Graphene\" (L.B Drissi, E.H Saidi, M.\nBousmina, CPM-11-01, Phys. Rev. D (2011)), we engineer a class of 4D lattice\nQCD fermions whose Dirac operators have two zero modes. We show that generally\nthe zero modes of the Dirac operator in hyperdiamond fermions are captured by a\ntensor {\\Omega}_{{\\mu}}^{l} with 4\\times5 complex components linking the\nEuclidean SO(4) vector {\\mu}; and the 5-dimensional representation of SU(5).\nThe Bori\\c{c}i-Creutz (BC) and the Karsten-Wilzeck (KW) models as well as their\nDirac zero modes are rederived as particular realizations of\n{\\Omega}_{{\\mu}}^{l}. Other features are also given. Keywords: Lattice QCD,\nBori\\c{c}i-Creutz and Karsten-Wilzeck models, 4D hyperdiamond, 4D graphene,\nSU(5) Symmetry.",
        "positive": "Neutron Electric Dipole Moment and Tensor Charges from Lattice QCD: We present Lattice QCD results on the neutron tensor charges including, for\nthe first time, a simultaneous extrapolation in the lattice spacing, volume,\nand light quark masses to the physical point in the continuum limit. We find\nthat the \"disconnected\" contribution is smaller than the statistical error in\nthe \"connected\" contribution. Our estimates in the $\\bar{\\text{MS}}$ scheme at\n$2$ GeV, including all systematics, are $g_T^{d-u}=1.020(76)$, $g_T^d =\n0.774(66)$, $g_T^u = - 0.233(28)$, and $g_T^s = 0.008(9)$. The flavor diagonal\ncharges determine the size of the neutron electric dipole moment (EDM) induced\nby quark EDMs that are generated in many new scenarios of CP-violation beyond\nthe Standard Model (BSM). We use our results to derive model-independent bounds\non the EDMs of light quarks and update the EDM phenomenology in split\nSupersymmetry with gaugino mass unification, finding a stringent upper bound of\n$d_n < 4 \\times 10^{-28} \\, e$ cm for the neutron EDM in this scenario."
    },
    {
        "anchor": "Lattice Charge Overlap I: Elastic Limit of Pi and Rho Mesons: Using lattice QCD on a $16^{3}\\times 24$ lattice at $\\beta=6.0$, we examine\nthe elastic limit of charge overlap functions in the quenched approximation for\nthe pion and rho meson; results are compared to previous direct current\ninsertion calculations. A good signal is seen for the pion, but the electric\nand magnetic rho meson results are considerably noisier. We find that the pion\nand rho results are characterized by a monopole mass to rho mass ratio of\n$0.97(8)$ and $0.73(10)$, respectively. Assuming the functional form of the\nelectric and magnetic form factors are the same, we also find a rho meson\ng-factor of $g=2.25(34)$, consistent with the nonrelativistic quark model.",
        "positive": "Interaction potential between heavy $Q \\bar{Q}$ in color octet\n  configuration in QGP: We investigate the interaction between a heavy quark-antiquark pair in color\noctet configuration in gluon plasma. We calculate nonperturbatively an\neffective thermal potential for such a pair through the study of the\ncorrelation function of a hybrid state with $Q \\bar{Q}$ octet and an adjoint\ngluon source in the static limit. We discuss the extraction of an octet\npotential, and present results for the effective thermal potential between\noctet $Q \\bar{Q}$ pair in gluon plasma for moderately high temperatures\n$\\lesssim 2 T_c$. The implications of our result are discussed."
    },
    {
        "anchor": "Moments of charge fluctuations, pseudo-critical temperatures and\n  freeze-out in heavy ion collisions: We discuss universal properties of higher order cumulants of net baryon\nnumber fluctuations and point out their relevance for the analysis of\nfreeze-out and critical conditions in heavy ion collisions at LHC and RHIC.",
        "positive": "On the spectral density of the Wilson operator: We summarize our recent determination [1] of the spectral density of the\nWilson operator in the p-regime of Wilson chiral perturbation theory. We\ndiscuss the range of validity of our formula and a possible extension to our\ncomputation in order to better understand the behaviour of the spectral density\nin a finite volume close to the threshold."
    },
    {
        "anchor": "MLMC: Machine Learning Monte Carlo for Lattice Gauge Theory: We present a trainable framework for efficiently generating gauge\nconfigurations, and discuss ongoing work in this direction. In particular, we\nconsider the problem of sampling configurations from a 4D $SU(3)$ lattice gauge\ntheory, and consider a generalized leapfrog integrator in the molecular\ndynamics update that can be trained to improve sampling efficiency. Code is\navailable online at https://github.com/saforem2/l2hmc-qcd.",
        "positive": "On the Lefschetz thimbles structure of the Thirring model: The complexification of field variables is an elegant approach to attack the\nsign problem. In one approach one integrates on Lefschetz thimbles: over them,\nthe imaginary part of the action stays constant and can be factored out of the\nintegrals so that on each thimble the sign problem disappears. However, for\nsystems in which more than one thimble contribute one is faced with the\nchallenging task of collecting contributions coming from multiple thimbles. The\nThirring model is a nice playground to test multi-thimble integration\ntechniques; even in a low dimensional theory, the thimble structure can be\nrich. It has been shown since a few years that collecting the contribution of\nthe dominant thimble is not enough to capture the full content of the theory.\nWe report preliminary results on reconstructing the complete results from\nmultiple thimble simulations."
    },
    {
        "anchor": "The finite temperature QCD transition in external magnetic fields: The effect of an external magnetic field on the finite temperature transition\nof QCD is studied. We measure thermodynamic observables including the quark\ncondensates and susceptibilities and the strange quark number susceptibility.\nWe generate configurations at various values of the quantized magnetic flux\nwith N_f=2+1 flavors of stout smeared staggered quarks at physical quark\nmasses. We perform the renormalization of our observables and approach the\ncontinuum limit with N_t=6,8 and 10 lattices. We also check finite volume\neffects using various lattice volumes. Our main result is that the transition\ntemperature significantly decreases with growing magnetic field, and that the\ntransition remains an analytic crossover up to our largest external field eB ~\n1 GeV^2.",
        "positive": "Crossover Between Weakly and Strongly Self-avoiding Random Surfaces: We investigate the crossover between weak and strong self-avoidance in a\nsimulation of random surfaces with extrinsic curvature. We consider both\ndynamically triangulated and rigid surfaces with the two possible\ndiscretizations of the extrinsic curvature term."
    },
    {
        "anchor": "A lattice QCD study of pion-nucleon scattering in the Roper channel: We present a lattice QCD study of the puzzling positive-parity nucleon\nchannel, where the Roper resonance $N^*(1440)$ resides in experiment. The study\nis based on an ensemble of gauge configurations with $N_f=2+1$ Wilson-clover\nfermions with a pion mass of $156$ MeV and lattice size $L=2.9$ fm. We use\nseveral $qqq$ interpolating fields combined with $N\\pi$ and $N\\sigma$\ntwo-hadron operators in calculating the energy spectrum in the rest frame.\nCombining experimental $N\\pi$ phase shifts with elastic approximation and the\nL\\\"uscher formalism suggests in the spectrum an additional energy level near\nthe Roper mass $m_R=1.43$ GeV for our lattice. We do not observe any such\nadditional energy level, which implies that $N\\pi$ elastic scattering alone\ndoes not render a low-lying Roper resonance. The current status indicates that\nthe $N^*(1440)$ might arise as dynamically generated resonance from coupling to\nother channels, most notably the $N\\pi\\pi$.",
        "positive": "Screening in two-dimensional gauge theories: We analyze the problem of screening in 1+1 dimensional gauge theories. Using\nQED2 as a warm-up for the non-abelian models we show the mechanism of the\nstring breaking, in particular the vanishing overlap of the Wilson loops to the\nbroken-string ground state that has been conjectured in higher-dimensional\nanalyses. We attempt to extend our analysis to non-integer charges in the\nquenched and unquenched cases, in pursuit of the numerical check of a renowned\nresult for the string tension between arbitrarily-charged fermions in the\nmassive Schwinger model."
    },
    {
        "anchor": "Monopoles of the Dirac type and color confinement in QCD -- Gauge\n  invariant mechansim: As a color confinement mechanism, a dual Meissner effect due to Abelian\nmonopoles involved in QCD has been discussed so far in various ways. But still\nthere is an important problem unsolved. It is gauge invariance of the schemes\nor, in other words, the reason why non-Abelian color confinement is explained\nby means of the Abelian dual Meissner effect. Here it is shown that a random\nAbelian method based on the violation of non-Abelian Bianchi identity (VNABI)\ncould prove SU(3) invariance and explain why color-singlets alone can survive\nin the confinement phase of QCD in the framework of the Abelian dual Meissner\neffect due to Abelian monopole condensation. This is completely different from\nthe 't Hooft's Abelian projection scheme which introduces an additional partial\ngauge-fixing or the idea of Bonati et al. which is based also on VNABI. Bonati\net al. say that VNABI is related to the 't Hooft tensor and the relation can\nprove the gauge invariance of the 't Hooft's Abelian projection schemes. But\nthe last idea is found to be incorrect. Existence of the relation between VNABI\nand the 't Hooft tensor alone can not account for gauge invariance of 't\nHooft's Abelian projection schemes.",
        "positive": "$B_K$ with improved staggered fermions: analysis using SU(2) staggered\n  chiral perturbation theory: We report updated results for $B_K$ calculated using HYP-smeared staggered\nfermions on the MILC asqtad 2+1 flavor lattices. We use four different lattice\nspacings ($a \\approx$ 0.12, 0.09, 0.06 and 0.045 fm) to control the continuum\nextrapolation. We use SU(2) staggered chiral perturbation theory to do the data\nanalysis. We find that $B_K(\\text{NDR}, \\mu=2 \\text{GeV}) = 0.526 \\pm 0.007 \\pm\n0.024$ and $\\hat{B}_K = B_K(\\text{RGI}) = 0.720 \\pm 0.010 \\pm 0.033$. Here the\nfirst error is statistical and the second systematic. The dominant source of\nerror is that due to our use of a truncated (one-loop) matching factor."
    },
    {
        "anchor": "IR fixed points in $SU(3)$ gauge Theories: We propose a novel RG method to specify the location of the IR fixed point in\nlattice gauge theories and apply it to the $SU(3)$ gauge theories with $N_f$\nfundamental fermions. It is based on the scaling behavior of the propagator\nthrough the RG analysis with a finite IR cut-off, which we cannot remove in the\nconformal field theories in sharp contrast with the confining theories. The\nmethod also enables us to estimate the anomalous mass dimension in the\ncontinuum limit at the IR fixed point. We perform the program for $N_f=16, 12,\n8 $ and $N_f=7$ and indeed identify the location of the IR fixed points in all\ncases.",
        "positive": "Renormalization of $(2+1)D$ scalar Weyl spinors interactions on lattices\n  using the Clifford groups: We consider symplectic quaternions instead of unitary spinors sitting on a\nlattice, and calculate the fixed point Wilson action on a finite $2D$ plane\nexpanded by $u_1 a e_1+ u_2 a e_2$ and on two $2D$ planes separated by $a\ne_1\\wedge e_2$. Only the nearlest neighbor interactions are considered.\nFollowing Migdal and Kadanoff, we perform the renormalization of the Wilson\naction by making the lattice spacing $(\\frac{1}{2})^{h}a$ $(h=0,\\cdots,11 )$,\nin order to simulate bosonic and solitonic phonon propagation in materials.\nRenormalization group method of Benfatto and Gallavotti for $(2+1)D$ scalar\n$\\phi^4$ system for sound propagation in Fermi sea is applied and feasibility\nof numerical simulation is discussed."
    },
    {
        "anchor": "Nature of the Vacuum inside the Color Flux Tube: The interior of the color flux tube joining a quark pair can be probed by\nevaluating the correlator of pair of Polyakov loops in a vacuum modified by\nanother Polyakov pair, in order to check the dual superconductivity conjecture\nwhich predicts a deconfined, hot core. We also point out that at the critical\npoint of any 3D gauge theories with a continuous deconfining transition the\nSvetitsky-Yaffe conjecture provides us with an analytic expression of the\nPolyakov correlator as a function of the position of the probe inside the flux\ntube. Both these predictions are compared with numerical results in 3D Z2 gauge\nmodel finding complete agreement.",
        "positive": "Resonance properties from the finite-volume energy spectrum: A new method based on the concept of probability distribution is proposed to\nanalyze the finite volume energy spectrum in lattice QCD. Using synthetic\nlattice data, we demonstrate that for the channel with quantum numbers of the\nDelta-resonance a clear resonance structure emerges in such an analysis.\nConsequently, measuring the volume-dependence of the energy levels in lattice\nQCD will allow to determine the mass and the width of the Delta with reasonable\naccuracy."
    },
    {
        "anchor": "Confining Forces and String Formation from the Lattice: We show the running coupling as derived from the SU(3) QQ potential and\ndiscuss preliminary results on spin dependent heavy quark potentials from high\nstatistics lattice simulations of SU(2) gauge theory. The precision suffices to\nstudy scaling properties and lattice artifacts (at short distances). We\nidentify the Coulomb like short range interaction as a mixed vector-scalar\nexchange. We measure flux tube formation between a static QQ pair over physical\ndistances up to 2 fm, with a spatial resolution as small as .05 fm. Consistency\nwith the string picture is found for separation larger than about 1 fm, with a\nhalf width of the profile of approximately .7 fm.",
        "positive": "Sparsening Algorithm for Multi-Hadron Lattice QCD Correlation Functions: Modern advances in algorithms for lattice QCD calculations have steadily\ndriven down the resources required to generate gauge field ensembles and\ncalculate quark propagators, such that, in cases relevant to nuclear physics,\nperforming quark contractions to assemble correlation functions from\npropagators has become the dominant cost. This work explores a propagator\nsparsening algorithm for forming correlation functions describing multi-hadron\nsystems, such as light nuclei, with reduced computational cost. The algorithm\nconstructs correlation functions from sparsened propagators defined on a\ncoarsened lattice geometry, where the sparsened propagators are obtained from\npropagators computed on the full lattice. This algorithm is used to study the\nlow-energy QCD ground-state spectrum using a single Wilson-clover lattice\nensemble with $m_{\\pi} \\approx 800$ MeV. It is found that the extracted ground\nstate masses and binding energies, as well as their statistical uncertainties,\nare consistent when determined from correlation functions constructed from\nsparsened and full propagators. In addition, while evidence of modified\ncouplings to excited states is observed in sparsened correlation functions, it\nis demonstrated that these effects can be removed, if desired, with an\ninexpensive modification to the sparsened estimator."
    },
    {
        "anchor": "Least-Squared Optimized Polynomials for Smeared Link Actions: We introduce a numerical method for generating the approximating polynomials\nused in fermionic calculations with smeared link actions. We investigate the\nstability of the algorithm and determine the optimal weight function and the\noptimal type of discretization. The achievable order of polynomial\napproximation reaches several thousands allowing fermionic calculations using\nthe Hypercubic Smeared Link action even with physical quark masses.",
        "positive": "Lattice Perturbation Theory by Langevin Dynamics: We present an application of the standard Langevin dynamics to the problem of\nweak coupling perturbative expansions for Lattice QCD. This method can be\napplied to the computation of the most general observables. In this preliminary\nwork we will concentrate in particular on the computation of the perturbative\nterms of the $1\\times 1$ Wilson loop, up to fourth order. It is shown that a\nstochastic gauge fixing is a possible solution to the problem of divergent\nfluctuations which affect higher order coefficients."
    },
    {
        "anchor": "Locality and exponential error reduction in numerical lattice gauge\n  theory: In non-abelian gauge theories without matter fields, expectation values of\nlarge Wilson loops and loop correlation functions are difficult to compute\nthrough numerical simulation, because the signal-to-noise ratio is very rapidly\ndecaying for increasing loop sizes. Using a multilevel scheme that exploits the\nlocality of the theory, we show that the statistical errors in such\ncalculations can be exponentially reduced. We explicitly demonstrate this in\nthe SU(3) theory, for the case of the Polyakov loop correlation function, where\nthe efficiency of the simulation is improved by many orders of magnitude when\nthe area bounded by the loops exceeds 1 fm^2.",
        "positive": "P-wave meson properties with Wilson quarks: We describe two calculations involving P-wave mesons made of Wilson quarks:\nthe strong coupling constant $\\alpha_s$ in the presence of two flavors of light\ndynamical fermions and the mass and decay constant of the $a_1$ meson."
    },
    {
        "anchor": "The chemical potential in the transfer matrix and in the path integral\n  formulation of QCD on a lattice: We define the chemical potential as the Lagrange multiplier of the baryon\ncharge operator in the transfer matrix formalism of QCD on a lattice.\nTransforming the partition function into an euclidean path integral we get the\nHasenfratz-Karsh action both for Wilson and Kogut-Susskind fermions. In the\nlatter case the chemical potential in the spin-diagonal basis is half that in\nthe flavour basis. Some open problems in the spin-diagonal basis are pointed\nout.",
        "positive": "The $\\mathbb{C}$P(2) Model at Non-Zero Chemical Potential: Recently the simulation of quantum field theories using man-made physical\nsystems has become realistic. In this publication we present numerical results\nwhich support the use of quantum simulation experiments to study quantum field\ntheories at non-zero chemical potential. We have numerically simulated the\n(1+1)-d $\\mathbb{C}$P(2) model, which shares several interesting features with\nQCD, namely asymptotic freedom, a dynamically generated mass gap and\ntopological sectors, via dimensional reduction of a (2+1)-d microscopic theory\nof SU(3) quantum spins. Numerical results for the particle number density as a\nfunction of chemical potential are presented."
    },
    {
        "anchor": "The spectrum of charmed mesons from dynamical anisotropic lattices: We present our preliminary analysis for the chamonium and D$_s$ spectra\nobtained from N$_f=2$ dynamical anisotropic lattices. We use 12$^3\\times 80$\nlattices with lattice spacing $a_t=7.35$ GeV$^{-1}$ and anisotropy of six.\nMeson correlators are computed using all-to-all propagators together with\nvariational analysis.",
        "positive": "Fluctuations, correlations and the sign problem in QCD: We study the distribution of the phase angle and the magnitude of the fermion\ndeterminant as well as its correlation with the chiral condensate and the\nbaryon number for QCD at non-zero quark chemical potential. Results are derived\nto one-loop order in Chiral Perturbation Theory (ChPT), as well as by\nanalytical and numerical calculations in QCD in one Euclidean dimension. We\nfind a qualitative change of the distribution of the phase of the fermion\ndeterminant when the quark mass enters the spectrum of the Dirac operator: it\nchanges from a periodicized Gaussian distribution to a periodicized Lorentzian\ndistribution. We also explore the possibility that some observables remain\nweakly correlated with the phase of the fermion determinant even though the\nsign problem is severe. We discuss the practical implications of our findings\non lattice simulations of QCD at non-zero baryon chemical potential."
    },
    {
        "anchor": "Nucleon generalized form factors from two-flavor lattice QCD: We determine the generalized form factors, which correspond to the second\nMellin moment (i.e., the first $x$-moment) of the generalized parton\ndistributions of the nucleon at leading twist. The results are obtained using\nlattice QCD with $N_f=2$ nonperturbatively improved Wilson fermions, employing\na range of quark masses down to an almost physical value with a pion mass of\nabout 150 MeV. We also present results for the isovector quark angular momentum\nand for the first $x$-moment of the transverse quark spin density. We compare\ntwo different fit strategies and find that directly fitting the ground state\nmatrix elements to the functional form expected from Lorentz invariance and\nparametrized in terms of form factors yields comparable, and usually more\nstable results than the traditional approach where the form factors are\ndetermined from an overdetermined linear system based on the fitted matrix\nelements.",
        "positive": "Hadronic light-by-light scattering contribution to the muon g-2 from\n  lattice QCD : Methodology: The hadronic light-by-light scattering contribution to the muon g-2 is the\nmost troublesome component of its theoretical prediction; (1) it cannot be\ndetermined from the other measurable quantities, (2) the dimensional argument\nand the estimation based on hadronic models imply that the magnitude of this\ncontribution may be comparable to the discrepancy between the standard model\nprediction and the experimental value. The direct approach to evaluate the\nhadronic light-by-light scattering contribution requires the evaluation of the\ncorrelation function of {\\it four} hadronic electromagnetic currents, and the\nsummation of it over two independent four-momenta of off-shell photons, which\nis far from the reach of direct lattice simulation. Here we propose an\nalternative method using combined (QCD + QED) lattice simulations to evaluate\nthe hadronic light-by-light scattering contribution."
    },
    {
        "anchor": "Center Vortices and Monopoles without lattice Gribov copies: We construct a smooth gauge for the adjoint field which is free of\nambiguities on the lattice. In this Laplacian Center Gauge, center vortices and\nmonopoles appear together as local gauge defects. A numerical study of center\nvortices in SU(2) and SU(3) supports equality of the $Z_N$ and SU(N) string\ntensions in the continuum limit, and only then.",
        "positive": "Charmed-Bottom Mesons from Lattice QCD: We present ground state spectra of mesons containing a charm and a bottom\nquark. For the charm quark we use overlap valence quarks while a\nnon-relativistic formulation is utilized for the bottom quark on a background\nof 2+1+1 flavors HISQ gauge configurations generated by the MILC collaboration.\nThe hyperfine splitting between $1S$ states of $B_c$ mesons is found to be\n$56^{+4}_{-3}$ MeV. We also study the baryons containing only charm and bottom\nquarks and predict their ground state masses. Results are obtained at three\nlattice spacings."
    },
    {
        "anchor": "Large fluctuations in NSPT computations: a lesson from $O(N)$ non-linear\n  sigma models: In the last three decades, Numerical Stochastic Perturbation Theory (NSPT)\nhas proven to be an excellent tool for calculating perturbative expansions in\ntheories such as Lattice QCD, for which standard, diagrammatic perturbation\ntheory is known to be cumbersome. Despite the significant success of this\nstochastic method and the improvements made in recent years, NSPT apparently\ncannot be successfully implemented in low-dimensional models due to the\nemergence of huge statistical fluctuations: as the perturbative order gets\nhigher, the signal to noise ratio is simply not good enough. This does not come\nas a surprise, but on very general grounds, one would expect that the larger\nthe number of degrees of freedom, the less severe the fluctuations will be. By\nsimulating $2D$ $O(N)$ non-linear sigma models for different values of $N$, we\nshow that indeed the fluctuations are tamed in the large $N$ limit, meeting our\nexpectations. Having established this, we conclude discussing interesting\napplications of NSPT in the context of these theories.",
        "positive": "The topological properties of QCD at high temperature: problems and\n  perspectives: Lattice computations are the only first principle method capable of\nquantitatively assessing the topological properties of QCD at high temperature,\nhowever the numerical determination of the topological properties of QCD,\nespecially in the high temperature phase, is a notoriously difficult problem.\nWe will discuss the difficulties encountered in such a computation and some\nstrategies that have been proposed to avoid (or at least to alleviate) them."
    },
    {
        "anchor": "Pseudofermion observables for static heavy meson decay constants on the\n  lattice: A method based on the Monte Carlo inversion of the Dirac operator on the\nlattice provides low noise results for the correlations entering the definition\nof the heavy meson decay constant in the static limit. The method is\ncomplementary to the usual method of smeared sources, avoids the systematic\nerror arising from optimizing the size of the smearing volume and is more\nefficient for the values of lattice parameters that we have explored.",
        "positive": "Spectrum of SU(2) SUSY Yang-Mills Theory with a light gluino: We report on new results for the low lying spectrum of N=1 SUSY Yang-Mills\nTheory with SU(2) as the gauge group. Simulating on larger lattices at \\kappa =\n0.194 and \\beta = 2.3, we slowly approach the supersymmetric limit at\nm_{gluino} = 0."
    },
    {
        "anchor": "Lattice QCD Beyond Ground States: In this work, we apply black box methods (methods not requiring input) to\nfind excited-state energies. A variety of such methods for lattice QCD were\nintroduced at the 3rd iteration of the numerical workshop series. We first\nreview a selection of approaches that have been used in lattice calculations to\ndetermine multiple energy states: multiple correlator fits, the variational\nmethod and Bayesian fitting. In the second half, we will focus on a black box\nmethod, the multi-effective mass. We demonstrate the approach on anisotropic\nlattice data, extracting multiple states from single correlators. Without\ncomplicated operator construction or specialized fitting programs, the black\nbox method shows good consistency with the traditional approaches.",
        "positive": "Spectral function and excited states in lattice QCD with maximum entropy\n  method: We apply the maximum entropy method to extract the spectral functions for\npseudoscalar and vector mesons from hadron correlators previously calculated at\nfour different lattice spacings in quenched QCD with the Wilson quark action.\nWe determine masses and decay constants for the ground and excited states of\nthe pseudoscalar and vector channels from position and area of peaks in the\nspectral functions. We obtain the results, $m_{\\pi_1} = 660(590)$ MeV and\n$m_{\\rho_1} = 1540(570)$ MeV for the masses of the first excited state masses,\nin the continuum limit of quenched QCD. We also find unphysical states which\nhave infinite mass in the continuum limit, and argue that they are bound states\nof two doublers of the Wilson quark action. If the interpretation is correct,\nthis is the first time that the state of doublers is identified in lattice QCD\nnumerical simulations."
    },
    {
        "anchor": "Probing the chiral regime of Nf=2 QCD with mixed actions: We report on our first experiences with a mixed action setup with overlap\nvalence quarks and non-perturbatively O(a) improved Wilson sea quarks. For the\nlatter we employ CLS Nf=2 configurations with light sea quark masses at small\nlattice spacings. Exact chiral symmetry allows to consider very light valence\nquarks and explore the matching to (partially quenched) Chiral Perturbation\nTheory (ChPT) in a mixed epsilon/p-regime. We compute the topological\nsusceptibility and the low-lying spectrum of the massless Neuberger-Dirac\noperator for three values of the sea quark mass, and compare the sea quark mass\ndependence to NLO ChPT in the mixed regime. This provides two different\ndeterminations of the chiral condensate, as well as information about some NLO\nlow-energy couplings. Our results allow to test the consistency of the\nmixed-regime approach to ChPT, as well as of the mixed action framework.",
        "positive": "Speeding up the HMC: QCD with Clover-Improved Wilson Fermions: We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of\nsystems with dynamical fermions to two flavor QCD with clover-improvement. For\nour smallest quark masses we see a speed-up of more than a factor of two\ncompared with the standard algorithm."
    },
    {
        "anchor": "Dyons near the transition temperature in lattice QCD: We study the topological structure of QCD by cluster analysis. The fermionic\ntopological charge density is constructed from low lying modes of overlap Dirac\noperator for three types of temporal boundary conditions for fermion field.\nThis gives the possibility to mark all three dyon constitutents of KvBLL\ncaloron in gluonic fields. The gluonic topological charge density is appearing\nin the process of overimproved gradient flow process stopped at the moment when\nit maximally matches the fermionic topological charge density. This corresponds\nto the smearing of gluonic fields up to the scale set by dyon size. The\ntime-like Abelian monopoles and specific KvBLL pattern of Polyakov line\ncorrelate with topological clusters.",
        "positive": "Relevant gluonic energy scale of spontaneous chiral symmetry breaking\n  from lattice QCD: We analyze which momentum component of the gluon field induces spontaneous\nchiral symmetry breaking in lattice QCD. After removing the high-momentum or\nlow-momentum component of the gluon field, we calculate the chiral condensate\nand observe the roles of these momentum components. The chiral condensate is\nfound to be drastically reduced by removing the zero-momentum gluon. The\nreduction is about 40% of the total in our calculation condition. The\nnonzero-momentum infrared gluon also has a sizable contribution to the chiral\ncondensate. From the Banks-Casher relation, this result reflects the nontrivial\nrelation between the infrared gluon and the zero-mode quark."
    },
    {
        "anchor": "The Maximal Abelian Gauge in SU(3) Lattice Gauge Theory: We gauge fix 600 SU(3) beta=6.0 configurations on a 16^4 lattice to a simple\nform of the maximal abelian gauge. We project the SU(3) valued links to the\nU(1)xU(1) subgroup, and extract U(1)xU(1) and monopole string tensions. After\ngauge fixing to the indirect center gauge, the U(1)xU(1) links are projected to\nZ(3) and a vortex string tension is measured. The vortex and magnetic current\ndensities are measured.",
        "positive": "Numerical Study of the Fundamental Modular Region in the Minimal Landau\n  Gauge: We study numerically the so-called fundamental modular region Lambda, a\nregion free of Gribov copies, in the minimal Landau gauge for pure SU(2)\nlattice gauge theory. To this end we evaluate the influence of Gribov copies on\nseveral quantities --- such as the smallest eigenvalue of the Faddeev-Popov\nmatrix, the third and the fourth derivatives of the minimizing function, and\nthe so-called horizon function --- which are used to characterize the region\nLambda. Simulations are done at four different values of the coupling: beta =\n0, 0.8, 1.6, 2.7, and for volumes up to 16^4. We find that typical (thermalized\nand gauge-fixed) configurations, including those belonging to the region\nLambda, lie very close to the Gribov horizon $\\partial \\Omega$, and are\ncharacterized, in the limit of large lattice volume, by a negative-definite\nhorizon tensor."
    },
    {
        "anchor": "Euclidean correlation functions of the topological charge density: We present first results of our study on the Euclidean topological charge\ndensity correlation function. In order to get a well defined topological charge\ndensity and to improve the signal of the correlation function at large\nseparations we make use of the gradient flow. We investigate the flow-time\ndependence on fine quenched lattices. The final goal of this study is to\nperform a continuum extrapolation for the pure SU(3) plasma and to extract the\nrelated transport coefficient, the sphaleron rate.",
        "positive": "Lattice QCD study of the elastic and transition form factors of charmed\n  baryons: I review the progress made in calculating the elastic and transition form\nfactors of charmed baryons from lattice simulations."
    },
    {
        "anchor": "Stabilizing the electroweak vacuum by higher dimensional operators in a\n  Higgs-Yukawa model: The Higgs boson discovery at the LHC with a mass of approximately 126 GeV\nsuggests, that the electroweak vacuum of the standard model may be metastable\nat very high energies. However, any new physics beyond the standard model can\nchange this picture. We want to address this important question within a\nlattice Higgs-Yukawa model as the limit of the standard model (SM). In this\nframework we will probe the effect of a higher dimensional operator for which\nwe take a $(\\phi^{\\dagger}\\phi)^3$-term. Such a term could easily originate as\na remnant of physics beyond the SM at very large scales.\n  As a first step we investigate the phase diagram of the model including such\na $(\\phi^{\\dagger}\\phi)^3$ operator. Exploratory results suggest the existence\nof regions in parameter space where first order transitions turn to second\norder ones, indicating the existence of a tri-critical line. We will explore\nthe phase structure and the consequences for the stability of the SM, both\nanalytically by investigating the constraint effective potential in lattice\nperturbation theory, and by studying the system non-perturbatively using\nlattice simulations.",
        "positive": "A guide to light-cone PDFs from Lattice QCD: an overview of approaches,\n  techniques and results: Within the theory of Quantum Chromodynamics (QCD), the rich structure of\nhadrons can be quantitatively characterized, among others, using a basis of\nuniversal non-perturbative functions: parton distribution functions (PDFs),\ngeneralized parton distributions (GPDs), transverse-momentum dependent\ndistributions (TMDs) and distribution amplitudes (DAs). For more than half a\ncentury, there has been a joint experimental and theoretical effort to obtain\nthese partonic functions. However, the complexity of the strong interactions\nhas placed severe limitations, and first-principle results on the distributions\nwas extracted mostly from their moments computed in Lattice QCD. Recently,\nbreakthrough ideas changed the landscape and several approaches were proposed\nto access the distributions themselves on the lattice.\n  In this paper, we review in considerable detail approaches directly related\nto partonic distributions. We highlight a recent idea proposed by X. Ji on\nextracting quasi-distributions that spawned renewed interest in the whole field\nand sparked the largest amount of numerical studies of Lattice QCD. We discuss\ntheoretical and practical developments, including challenges that had to be\novercome, with some yet to be handled. We also review numerical results,\nincluding a discussion based on evolving understanding of the underlying\nconcepts and theoretical and practical progress. Particular attention is given\nto important aspects that validated the quasi-distribution approach, such as\nrenormalization, matching to light-cone distributions and lattice techniques.\n  In addition to a thorough discussion of quasi-distributions, we consider\nother approaches: hadronic tensor, auxiliary quark methods, pseudo-PDFs, OPE\nwithout OPE and good lattice cross sections. In closing, we provide prospects\nof the field, with emphasis on the necessary conditions to obtain results with\ncontrolled uncertainties."
    },
    {
        "anchor": "Low-Temperature Series for the Correlation Length in $d=3$ Ising Model: We extend low-temperature series for the second moment of the correlation\nfunction in $d=3$ simple-cubic Ising model from $u^{15}$ to $u^{26}$ using\nfinite-lattice method, and combining with the series for the susceptibility we\nobtain the low-temperature series for the second-moment correlation length to\n$u^{23}$. An analysis of the obtained series by inhomogeneous differential\napproximants gives critical exponents $ 2\\nu^{\\prime} + \\gamma^{\\prime} \\approx\n2.55 $ and $ 2\\nu^{\\prime} \\approx 1.27 $.",
        "positive": "Topological susceptibility and chiral condensate with $N_f=2+1+1$\n  dynamical flavors of maximally twisted mass fermions: We study the 'spectral projector' method for the computation of the chiral\ncondensate and the topological susceptibility, using $N_f=2+1+1$ dynamical\nflavors of maximally twisted mass Wilson fermions. In particular, we perform a\nstudy of the quark mass dependence of the chiral condensate $\\Sigma$ and\ntopological susceptibility $\\chi_{top}$ in the range $270 MeV < m_{\\pi} < 500\nMeV$ and compare our data with analytical predictions. In addition, we compute\n$\\chi_{top}$ in the quenched approximation where we match the lattice spacing\nto the $N_f=2+1+1$ dynamical simulations. Using the Kaon, $\\eta$ and\n$\\eta^{\\prime}$ meson masses computed on the $N_f=2+1+1$ ensembles, we then\nperform a preliminary test of the Witten-Veneziano relation."
    },
    {
        "anchor": "Bulk transitions of twelve flavor QCD and $U_A(1)$ symmetry: We present an update on our ongoing study on the nature of the bulk\ntransition observed at strong coupling in the SU(3) gauge theory with N_f = 12\nflavors in the fundamental representation. We show evidence that there is a\nfirst order chiral symmetry breaking bulk transition separating a region at\nweak coupling where chiral symmetry is restored from a region at strong\ncoupling where chiral symmetry is broken. We also discuss hints of a separate\npartial restoration of U_A(1) at weaker coupling. The results are in agreement\nwith restoration of conformality in non abelian gauge theories as the number of\nflavors is increased.",
        "positive": "$N_f = 2+1+1$ flavours of twisted mass quarks: cut-off effects at\n  tree-level of perturbation theory: We present a calculation of cut-off effects at tree-level of perturbation\ntheory for the K and D mesons using the twisted mass formulation of lattice\nQCD. The analytical calculations are performed in the time-momentum frame. The\nrelative sizes of cut-off effects are compared for the pion, the kaon and the D\nmeson masses. In addition, different realizations of maximal twist condition\nare considered and the corresponding cut-off effects are analyzed."
    },
    {
        "anchor": "Slow running of the Gradient Flow coupling from 200 MeV to 4 GeV in\n  $N_{\\rm f}=3$ QCD: Using a finite volume Gradient Flow (GF) renormalization scheme with\nSchr\\\"odinger Functional (SF) boundary conditions, we compute the\nnon-perturbative running coupling in the range $2.2 \\lesssim {\\bar\ng}_\\mathrm{GF}^2(L) \\lesssim 13$. Careful continuum extrapolations turn out to\nbe crucial to reach our high accuracy. The running of the coupling is always\nbetween one-loop and two-loop and very close to one-loop in the region of\n$200\\,{\\rm MeV} \\lesssim \\mu=1/L \\lesssim 4\\,{\\rm GeV}$. While there is no\nconvincing contact to two-loop running, we match non-perturbatively to the SF\ncoupling with background field. In this case we know the $\\mu$ dependence up to\n$\\sim 100\\,{\\rm GeV}$ and can thus connect to the $\\Lambda$-parameter.",
        "positive": "Latent heat at the first order phase transition point of SU(3) gauge\n  theory: We calculate the energy gap (latent heat) and pressure gap between the hot\nand cold phases of the SU(3) gauge theory at the first order deconfining phase\ntransition point. We perform simulations around the phase transition point with\nthe lattice size in the temporal direction Nt=6, 8 and 12 and extrapolate the\nresults to the continuum limit. We also investigate the spatial volume\ndependence. The energy density and pressure are evaluated by the derivative\nmethod with non-perturabative anisotropy coefficients. We adopt a multi-point\nreweighting method to determine the anisotropy coefficients. We confirm that\nthe anisotropy coefficients approach the perturbative values as Nt increases.\nWe find that the pressure gap vanishes at all values of Nt when the\nnon-perturbative anisotropy coefficients are used. The spatial volume\ndependence in the latent heat is found to be small on large lattices.\nPerforming extrapolation to the continuum limit, we obtain $ \\Delta\n\\epsilon/T^4 = 0.75 \\pm 0.17 $ and $ \\Delta (\\epsilon -3 p)/T^4 = 0.623 \\pm\n0.056.$"
    },
    {
        "anchor": "Glueball mass measurements from improved staggered fermion simulations: We present the first 2+1 flavour spectrum measurements of glueball states\nusing high statistics simulations with improved staggered fermions. We find a\nspectrum consistent with quenched measurements of scalar, pseudoscalar\nandtensor glueball states. The measurements were made using 5000 configurations\nat a lattice spacing of 0.123 fm and pion mass of 280 MeV and 3000\nconfigurations at 0.092 fm with a pion mass of 360 MeV. We see some evidence of\ncoupling to 2 pion states. We compare our results with the experimental\nglueball candidate spectrum as well as quenched glueball estimates.",
        "positive": "Lattice investigations of the chimera baryon spectrum in the Sp(4) gauge\n  theory: We report the results of lattice numerical studies of the Sp(4) gauge theory\ncoupled to fermions (hyperquarks) transforming in the fundamental and two-index\nantisymmetric representations of the gauge group. This strongly-coupled theory\nis the minimal candidate for the ultraviolet completion of composite Higgs\nmodels that facilitate the mechanism of partial compositeness for generating\nthe top-quark mass. We measure the spectrum of the low-lying, half-integer\nspin, bound states composed of two fundamental and one antisymmetric\nhyperquarks, dubbed chimera baryons, in the quenched approximation. In this\nfirst systematic, non-perturbative study, we focus on the three lightest\nparity-even chimera-baryon states, in analogy with QCD, denoted as\n$\\Lambda_{\\rm CB}$, $\\Sigma_{\\rm CB}$ (both with spin 1/2), and $\\Sigma_{\\rm\nCB}^\\ast$(with spin 3/2). The spin-1/2 such states are candidates of the top\npartners. The extrapolation of our results to the continuum and\nmassless-hyperquark limit is performed using formulae inspired by QCD\nheavy-baryon Wilson chiral perturbation theory. Within the range of hyperquark\nmasses in our simulations, we find that $\\Sigma_{\\mathrm{CB}}$ is not heavier\nthan $\\Lambda_{\\mathrm{CB}}$."
    },
    {
        "anchor": "Properties of Color-Coulomb String Tension: We study the properties of the color-Coulomb string tension obtained from the\ninstantaneous part of gluon propagators in Coulomb gauge using quenched SU(3)\nlattice simulation.\n  In the confinement phase, the dependence of the color-Coulomb string tension\non the QCD coupling constant is smaller than that of the Wilson loop string\ntension. On the other hand, in the deconfinement phase, the color-Coulomb\nstring tension does not vanish even for $T/T_c = 1 \\sim 5$, the temperature\ndependence of which is comparable with the magnetic scaling, dominating the\nhigh temperature QCD. Thus, the color-Coulomb string tension is not an order\nparameter of QGP phase transition.",
        "positive": "Where is the string limit in QCD?: The energies of glue in the presence of a static quark-antiquark pair are\ncalculated for separations r ranging from 0.1 fm to 4 fm and for various\nquark-antiquark orientations on the lattice. Our simulations use an improved\ngauge-field action on anisotropic space-time lattices. Discretization errors\nand finite volume effects are studied. We find that the spectrum does not\nexhibit the expected onset of the universal pi/r Goldstone excitations of the\neffective QCD string, even for r as large as 4 fm. Our results cast serious\ndoubts on the validity of treating glue in terms of a fluctuating string for r\nbelow 2 fm. Retardation effects in the Upsilon system are also studied by\ncomparing level splittings from the Born-Oppenheimer approximation with those\ndirectly obtained in simulations."
    },
    {
        "anchor": "Chiral Properties of Pseudoscalar Mesons on a Quenched $20^4$ Lattice\n  with Overlap Fermions: The chiral properties of the pseudoscalar mesons are studied numerically on a\nquenched $20^4$ lattice with the overlap fermion. We elucidate the role of the\nzero modes in the meson propagators, particularly that of the pseudoscalar\nmeson. The non-perturbative renormalization constant $Z_A$ is determined from\nthe axial Ward identity and is found to be almost independent of the quark mass\nfor the range of quark masses we study; this implies that the $O(a^2)$ error is\nsmall. The pion decay constant, $f_{\\pi}$, is calculated from which we\ndetermine the lattice spacing to be 0.148 fm. We look for quenched chiral log\nin the pseudoscalar decay constants and the pseudoscalar masses and we find\nclear evidence for its presence. The chiral log parameter $\\delta$ is\ndetermined to be in the range 0.15 -- 0.4 which is consistent with that\npredicted from quenched chiral perturbation theory.",
        "positive": "The K+K+ Scattering Length from Lattice QCD: The K+K+ scattering length is calculated in fully-dynamical lattice QCD with\ndomain-wall valence quarks on the MILC asqtad-improved gauge configurations\nwith rooted staggered sea quarks. Three-flavor mixed-action chiral perturbation\ntheory at next-to-leading order, which includes the leading effects of the\nfinite lattice spacing, is used to extrapolate the results of the lattice\ncalculation to the physical value of m_{K+}/f_{K+}. We find m_{K+} a_{K+K+} =\n-0.352 +- 0.016, where the statistical and systematic errors have been combined\nin quadrature."
    },
    {
        "anchor": "Non-perturbative renormalization of quark mass in Nf=2+1 QCD with the\n  Schroedinger functional scheme: We present an evaluation of the quark mass renormalization factor for Nf=2+1\nQCD. The Schroedinger functional scheme is employed as the intermediate scheme\nto carry out non-perturbative running from the low energy to deep in the high\nenergy perturbative region. The regularization independent step scaling\nfunction of the quark mass is obtained in the continuum limit. Renormalization\nfactors for the pseudo scalar density and the axial vector current are also\nevaluated for the same action and the bare couplings as two recent large scale\nNf=2+1 simulations; previous work of the CP-PACS/JLQCD collaboration, which\ncovered the up-down quark mass range heavier than m_pi=500 MeV and that of\nPACS-CS collaboration on the physical point using the reweighting technique.",
        "positive": "$B_s \\to D^{(*)}_s$ form factors from lattice QCD with ${ N_f}=2$\n  Wilson-clover quarks: We report on a two-flavour lattice QCD determination of the $B_s\\to D_s$ and\n$B_s\\to D_s^*$ transitions, which in the heavy quark limit can be parameterised\nby the form factors $\\mathcal{G}$, and $h_{\\text A_1}$, $h_{\\text A_2}$ and\n$h_{\\text A_3}$. In the search of New Physics through tests of lepton-flavour\nuniversality, $B_s$ decay channels are complementary to $B$ decays and widely\nstudied at $B$ factories and LHCb. The purpose of our study is to explore a\nsuitable method to extract form factors associated with $b\\to c$ currents from\nlattice QCD. In particular, we present numerical results for $\\mathcal{G}$ and\n$h_{\\text A_1}$."
    },
    {
        "anchor": "Why (staggered fermions)^{1/4} fail at finite density: Because the staggered fermion determinant is complex at nonzero mu, taking\nits fourth root leads to phase ambiguities. These unphysical effects cause the\nmeasure to become discontinuous; the problem becomes acute when Re mu exceeds\napproximately half the pion mass (when T>0 this rough bound probably moves\ntowards larger mu). We show how to overcome the problem, but only very close to\nthe continuum limit. This regime may be beyond reach with current resources.",
        "positive": "Computing the Mass Shift of Wilson and Staggered Fermions in the Lattice\n  Schwinger Model with Matrix Product States: Simulations of lattice gauge theories with tensor networks and quantum\ncomputing have so far mainly focused on staggered fermions. In this paper, we\nuse matrix product states to study Wilson fermions in the Hamiltonian\nformulation and present a novel method to determine the additive mass\nrenormalization. Focusing on the single-flavor Schwinger model as a benchmark\nmodel, we investigate the regime of a nonvanishing topological $\\theta$-term,\nwhich is inaccessible to conventional Monte Carlo methods. We systematically\nexplore the dependence of the mass shift on the volume, the lattice spacing,\nthe $\\theta$-parameter, and the Wilson parameter. This allows us to follow\nlines of constant renormalized mass, and therefore to substantially improve the\ncontinuum extrapolation of the mass gap and the electric field density. For\nsmall values of the mass, our continuum results agree with the theoretical\nprediction from mass perturbation theory. Going beyond Wilson fermions, our\ntechnique can also be applied to staggered fermions, and we demonstrate that\nthe results of our approach agree with a recent theoretical prediction for the\nmass shift at sufficiently large volumes."
    },
    {
        "anchor": "Hierarchical renormalization goup fixed points: Hierarchical renormalization group transformations are related to\nnon-associative algebras. Non-trivial infrared fixed points are shown to be\nsolutions of polynomial equations. At the example of a scalar model in\n$d(\\ge2)$ dimensions some methods for the solution of these algebraic equations\nare presented.",
        "positive": "$K_{\\rm L}\\rightarrow\u03bc^+\u03bc^-$ from lattice QCD: We propose a lattice-QCD-suitable framework for computing the two-photon\nlong-distance contribution to the complex $K_{\\rm L}\\rightarrow\\mu^+\\mu^-$\ndecay amplitude, where QED is treated perturbatively in the continuum and\ninfinite-volume. We provide preliminary numerical results on the\nquark-connected diagrams on one ensemble at physical pion mass from this\nmethod, with well-controlled systematic errors. The successful application of\nthis method will allow the determination of the dispersive part of the\naforementioned contribution from first-principles and enable a meaningful\ncomparison between the Standard-Model prediction and experiment."
    },
    {
        "anchor": "Analytical Formulae of the Polyakov and the Wilson Loops with Dirac\n  Eigenmodes in Lattice QCD: We derive an analytical gauge-invariant formula between the Polyakov loop\n$L_P$ and the Dirac eigenvalues $\\lambda_n$ in QCD, i.e., $L_P \\propto \\sum_n\n\\lambda_n^{N_t -1} \\langle n|\\hat U_4|n \\rangle$, in ordinary periodic square\nlattice QCD with odd-number temporal size $N_t$. Here, $|n\\rangle$ denotes the\nDirac eigenstate, and $\\hat U_4$ temporal link-variable operator. This formula\nis a Dirac spectral representation of the Polyakov loop in terms of Dirac\neigenmodes $|n\\rangle$. Because of the factor $\\lambda_n^{N_t -1}$ in the Dirac\nspectral sum, this formula indicates negligibly small contribution of low-lying\nDirac modes to the Polyakov loop in both confinement and deconfinement phases,\nwhile these modes are essential for chiral symmetry breaking. Next, we find a\nsimilar formula between the Wilson loop and Dirac modes on arbitrary square\nlattices, without restriction of odd-number size. This formula suggests a small\ncontribution of low-lying Dirac modes to the string tension $\\sigma$, or the\nconfining force. These findings support no crucial role of low-lying Dirac\nmodes for confinement, i.e., no direct one-to-one correspondence between\nconfinement and chiral symmetry breaking in QCD, which seems to be natural\nbecause heavy quarks are also confined even without light quarks or the chiral\nsymmetry.",
        "positive": "Perturbatively improving renormalization constants: Renormalization factors relate the observables obtained on the lattice to\ntheir measured counterparts in the continuum in a suitable renormalization\nscheme. They have to be computed very precisely which requires a careful\ntreatment of lattice artifacts. In this work we present a method to suppress\nthese artifacts by subtracting one-loop contributions proportional to the\nsquare of the lattice spacing calculated in lattice perturbation theory."
    },
    {
        "anchor": "The curvature of the freeze-out line in heavy ion collisions: We calculate the mean and variance of net-baryon number and net-electric\ncharge distributions from Quantum Chromodynamics (QCD) using a next-to-leading\norder Taylor expansion in terms of temperature and chemical potentials. We\ncompare these expansions with experimental data from STAR and PHENIX, determine\nthe freeze-out temperature in the limit of vanishing baryon chemical potential,\nand, for the first time, constrain the curvature of the freeze-out line through\na direct comparison between experimental data on net-charge fluctuations and a\nQCD calculation. We obtain a bound on the curvature coefficient, kappa_2^f <\n0.011, that is compatible with lattice QCD results on the curvature of the QCD\ntransition line.",
        "positive": "Topics in Effective Field Theory for Lattice QCD: In this work, we extend and apply effective field theory techniques to\nsystematically understand a subset of lattice artifacts which pollute the\nlattice correlation functions for a few processes of physical interest. Where\npossible, we compare to existing lattice QCD calculations. In particular, we\nextend the heavy baryon Lagrangian to the next order in partially quenched\nchiral perturbation theory and use it to compute the masses of the lightest\nspin-1/2 and spin-3/2 baryons to next-to-next-to leading order. We then\nconstruct the twisted mass chiral Lagrangian for baryons and apply it to\ncompute the lattice spacing corrections to the baryon masses simulated with\ntwisted mass lattice QCD.\n  We extend computations of the nucleon electromagnetic structure to account\nfor finite volume effects, as these observables are particularly sensitive to\nthe finite extent of the lattice. We resolve subtle peculiarities for lattice\nQCD simulations of polarizabilities and we show that using background field\ntechniques, one can make predictions for the 4 spin-dependent nucleon\npolarizabilities, quantities which are difficult to access experimentally.\n  We then discuss the two-pion system in finite volume, determining the\nexponentially small volume corrections necessary for lattice determinations of\nthe scattering parameters. We also determine the lattice spacing artifacts that\narise for a mixed-action lattice simulation of the two-pion system with\nGinsparg-Wilson valence quarks and staggered sea quarks. We show that the\nisospin 2 scattering length has a near continuum like behavior, differing from\nthe chiral perturbation theory calculation by a computable difference."
    },
    {
        "anchor": "On the phase diagram of the Higgs SU(2) model: The Higgs SU(2) model with fixed Higgs length is usually believed to have two\ndifferent phases at high gauge coupling (\\beta), separated by a line of first\norder transitions but not distinuguished by any typical symmetry associated\nwith a local order parameter, as first proved by Fradkin and Shenker. We show\nthat in regions of the parameter space where it is usually supposed to be a\nfirst order phase transition only a smooth crossover is in fact present.",
        "positive": "Monopole Currents in U(1) Lattice Gauge Theory: A Comparison to an\n  Effective Model based on Dual Superconductivity: We compare U(1) lattice gauge theory to an effective model of Maxwell and\nLondon equations. In the effective model there is only one free parameter, the\nLondon penetration depth lambda. It turns out that one can get good agreement\nbetween both models if one modifies the usual definition of magnetic monopole\ncurrents in U(1) lattice gauge theory. This comparison also shows that already\nat small distances fluctuations of the occuring string are important. Further,\nwe investigate the beta-dependence of the penetration depth and determine the\nsuppression of the monopole condensate in flux tubes."
    },
    {
        "anchor": "$B$-meson semileptonic decays from highly improved staggered quarks: We present an update for results on $B$-meson semileptonic decays using the\nhighly improved staggered quark (HISQ) action for both valence and 2+1+1 sea\nquarks. The use of the highly improved action, combined with the MILC\ncollaboration's gauge ensembles with lattice spacings down to $\\sim$0.03 fm,\nallows the $b$ quark to be treated with the same discretization as the lighter\nquarks. The talk will focus on updated results for $B_{(s)} \\to D_{(s)}$,\n$B_{(s)} \\to K$ scalar and vector form factors.",
        "positive": "Lattice study on a tetraquark state $T_{bb}$ in the HAL QCD method: We investigate a doubly-bottomed tetraquark state $T_{bb}$ $(bb\n\\bar{u}\\bar{d})$ with quantum number $I(J^P)=0(1^+)$ in $(2+1)$-flavor lattice\nQCD. Using the Non-Relativistic QCD (NRQCD) quark action for $b$ quarks, we\nhave extracted the coupled channel potential between $\\bar{B}\\bar{B}^*$ and\n$\\bar{B}^* \\bar{B}^*$ in the HAL QCD method at $a \\approx 0.09$ {fm} on\n$32^3\\times 64$ lattices. The potential predicts an existence of a bound\n$T_{bb}$ below the $\\bar{B}\\bar{B}^*$ threshold. At the physical pion mass\n$m_\\pi\\approx140$ {MeV} extrapolated from $m_\\pi\\approx 410,\\, 570,\\, 700$\n{MeV}, a binding energy with its statistical error is given by $E_{\\rm\nbinding}^{\\rm (coupled)} = 83(10)$ MeV from a coupled channel analysis where\neffects due to virtual $\\bar{B}^* \\bar{B}^*$ states are included through the\ncoupled channel potential, while we obtain $E_{\\rm binding}^{\\rm (single)} =\n155(17)$ MeV only from a potential for a single $\\bar{B}\\bar{B}^*$ channel.\nThis difference indicates that the effect from virtual $\\bar{B}^* \\bar{B}^*$\nstates is sizable to the binding energy of $T_{bb}$. Adding $\\pm 20$ MeV as\nempirical systematic error caused by the NRQCD approximation for $b$ quarks,\nour estimate of the $T_{bb}$ binding energy becomes $83(10)(20)$ MeV."
    },
    {
        "anchor": "QCD, Gauge Fixing, and the Gribov Problem: The standard techniques of gauge-fixing, such as covariant gauge fixing, are\nentirely adequate for the purposes of studies of perturbative QCD. However,\nthey fail in the nonperturbative regime due to the presence of Gribov copies.\nThese copies arise because standard local gauge fixing methods do not\ncompletely fix the gauge. Known Gribov-copy-free gauges, such as Laplacian\ngauge, are manifestly non-local. These issues are examined and the implications\nof non-local gauge-fixing for ghost fields, BRST invariance, and the proof of\nrenormalizability of QCD are considered.",
        "positive": "Transport and Connection to Heavy-ion Collisions via Heavy Flavor Probes: The heavy ion experiments in Relativistic Heavy Ion Collider (RHIC) and Large\nHadron Collider (LHC) are going through upgrade in the next five years,\nshifting their focus more on the hard processes in the new runs. One of the\nmain goals is to draw a finer image for the quark gluon plasma (QGP). The heavy\nflavor probes , which witness the whole history of heavy ion collision are\nparticularly sensitive to test the properties of QGP formed in such collisions.\nThe lattice results for heavy flavor probes provide transport and\nphenomenological models crucial inputs to describe the experimental\nobservations like the strong suppression of the nuclear modification factor\n$R_{AA}$ and the non-zero azimuthal anisotropy at low $p_T$. In the last two\nyears we have seen significant advances in the lattice QCD studies of heavy\nflavor probes, including the in-medium quarkonium properties, the complex\nstatic quark-antiquark potential and the heavy quark diffusion from lattice\nsimulations at nonzero temperature. These achievements substantially deepen our\nunderstanding of the fate of quarkonium, the screening/unscreening of the\ncomplex potential and the temperature and quark mass dependence of the heavy\nquark diffusion in thermal medium. In these proceedings, we review recent\nresults and briefly discuss possible directions in these studies."
    },
    {
        "anchor": "Low energy chiral constants from epsilon-regime simulations with\n  improved Wilson fermions: We present a lattice QCD calculation of the low energy constants of the\nleading order chiral Lagrangian. In these simulations the epsilon regime is\nreached by using tree-level improved nHYP Wilson fermions combined with\nreweighting in the quark mass. We analyze two point functions on two ensembles\nwith lattices of size (1.85fm)^4 and (2.8fm)^4, and at several quark mass\nvalues between 4 and 20 MeV. The data are well fitted with next-to-leading\norder chiral perturbative formulae and predict F=90(4)MeV and\nSigma^(1/3)=248(6)MeV in the MS-bar scheme at 2 GeV.",
        "positive": "Testing universality and the fractional power prescription for the\n  staggered fermion determinant: In [Phys.Rev.Lett.92:162002 (2004), hep-lat/0312025] expressions for the\ncontinuous Euclidean time limits of various lattice fermion determinants were\nderived and compared in order to test universality expectations in Lattice QCD.\nHere we review that work with emphasis on its relevance for assessing the\nfractional power prescription for the determinant in dynamical staggered\nfermion simulations. Some new supplementary material is presented; in\nparticular the status of the \"universality anomaly\" is clarified: it is shown\nto be gauge field-independent and therefore physically inconsequential."
    },
    {
        "anchor": "$N\u03c0$-excited state contamination in nucleon 3-point functions using\n  ChPT: The $N\\pi$-state contribution to nucleon 3-pt functions involving the\npseudoscalar density $P(x)$ and the time component $A_4(x)$ of the axial vector\ncurrent are computed to LO in ChPT. In case of the latter the $N\\pi$\ncontribution is O($M_N$) enhanced compared to the single-nucleon ground state\ncontribution. In addition, a relative sign in two terms of the $N\\pi$\ncontribution leads an almost linear dependence on the operator insertion time,\nas it is observed in lattice data. In case of the pseudoscalar density the\n$N\\pi$ contribution is strongly dependent on the momentum transfer, leading to\na distortion of the pseudoscalar nucleon form factor. Finally, the $N\\pi$ state\ncontamination in the form factors result in a violation of the generalized\nGoldberger-Treiman relation as observed in various lattice calculations.",
        "positive": "Solutions to sign problems in lattice Yukawa models: We prove that sign problems in the traditional approach to some lattice\nYukawa models can be completely solved when the fermions are formulated using\nfermion bags and the bosons are formulated in the worldline representation. We\nprove this within the context of two examples of three dimensional models,\nsymmetric under $U_L(1) \\times U_R(1) \\times Z_2 ({Parity})$ transformations,\none involving staggered fermions and the other involving Wilson fermions. We\nargue that these models have interesting quantum phase transitions that can now\nbe studied using Monte Carlo methods."
    },
    {
        "anchor": "Neutron electric dipole moment using lattice QCD simulations at the\n  physical point: We extract the neutron electric dipole moment $\\vert \\vec{d}_N\\vert$ within\nthe lattice QCD formalism. We analyse one ensemble of $N_f=2+1+1$ twisted mass\nclover-improved fermions with lattice spacing of $a \\simeq 0.08 \\ {\\rm fm}$ and\nphysical values of the quark masses corresponding to a pion mass $m_{\\pi}\n\\simeq 139 \\ {\\rm MeV}$. The neutron electric dipole moment is extracted by\ncomputing the $CP$-odd electromagnetic form factor $F_3(Q^2 \\to 0)$ through\nsmall $\\theta$-expansion of the action. This approach requires the calculation\nof the topological charge for which we employ a fermionic definition by means\nof spectral projectors while we also provide a comparison with the gluonic\ndefinition accompanied by the gradient flow. We show that using the topological\ncharge from spectral projectors leads to absolute errors that are more than two\ntimes smaller than those provided when the field theoretic definition is\nemployed. We find a value of $\\vert \\vec{d}_N\\vert = 0.0009(24) \\ \\theta \\ e\n\\cdot {\\rm fm}$ when using the fermionic definition, which is statistically\nconsistent with zero.",
        "positive": "Hadron spectrum of QCD with one quark flavor: The latest results of an ongoing project for the lattice simulation of QCD\nwith a single quark flavor are presented. The Symanzik tree-level-improved\nWilson action is adopted in the gauge sector and the (unimproved) Wilson action\nfor the fermion. Results from new simulations with one step of Stout-smearing\n(rho=0.15) in the fermion action are discussed. The one-flavor theory is\nsimulated by a polynomial hybrid Monte Carlo algorithm (PHMC) at beta=4.0\ncorresponding to a = 0.13fm, on 16^3x32 and 24^3x48 lattices; the box-size is L\n= 2.1fm and L = 3.1fm, respectively. At the lightest simulated quark mass the\n(partially quenched) pion mass is ~300 MeV. The masses of the lightest bound\nstates are computed, including the flavor singlet scalar and pseudoscalar\nmesons sigma_s and eta_s, the scalar glueball 0^++, and the Delta^++ baryon.\nRelics of SUSY in the mass spectrum, expected from a large N_c orientifold\nequivalence with the N=1 supersymmetric Yang-Mills theory, are discussed."
    },
    {
        "anchor": "Performance of two-level sampling for the glueball spectrum in pure\n  gauge theory: The computation of the glueball spectrum is particularly challenging due to\nthe rapid decay of the signal-to-noise ratio of the correlation functions. To\naddress this issue, advanced techniques such as gauge link smearing and the\nvariational method are commonly employed to identify the spectrum before the\nsignal diminishes significantly. However, a significant improvement in the\nsignal-to-noise ratio can be achieved by utilising multilevel sampling\ntechniques. In this talk, we present a study of the glueball spectrum in pure\ngauge theory with a two-level algorithm. Specifically, we explore the relation\nbetween noise reduction and the various multilevel parameters, such as the\nwidth of the dynamical regions and the number of submeasurements.",
        "positive": "Hadron Spectrum from Dynamical Lattice QCD Simulations: Recent progress in unquenched lattice QCD simulations is reviewed with\nemphasis on understanding of chiral behavior for light quark masses."
    },
    {
        "anchor": "Hyperons in thermal QCD from the lattice: We study the spectrum of light baryons and hyperons as a function of\ntemperature using lattice gauge theory methods. We find that masses of positive\nparity states are temperature independent, within errors, in the hadronic\nphase. The negative parity states decrease in mass as the temperature\nincreases. Above the deconfining temperature, lattice correlators and spectral\nfunctions show a degeneracy between parity sectors, i.e. parity doubling. We\napply our findings to an in-medium Hadron Resonance Gas model. The techniques\nused in this study include direct analysis of the hadronic correlation\nfunctions, conventional fitting procedures, and the Maximum Entropy Method.",
        "positive": "Lattice simulations of real-time quantum fields: We investigate lattice simulations of scalar and nonabelian gauge fields in\nMinkowski space-time. For SU(2) gauge-theory expectation values of link\nvariables in 3+1 dimensions are constructed by a stochastic process in an\nadditional (5th) ``Langevin-time''. A sufficiently small Langevin step size and\nthe use of a tilted real-time contour leads to converging results in general.\nAll fixed point solutions are shown to fulfil the infinite hierarchy of\nDyson-Schwinger identities, however, they are not unique without further\nconstraints. For the nonabelian gauge theory the thermal equilibrium fixed\npoint is only approached at intermediate Langevin-times. It becomes more stable\nif the complex time path is deformed towards Euclidean space-time. We analyze\nthis behavior further using the real-time evolution of a quantum anharmonic\noscillator, which is alternatively solved by diagonalizing its Hamiltonian.\nWithout further optimization stochastic quantization can give accurate\ndescriptions if the real-time extend of the lattice is small on the scale of\nthe inverse temperature."
    },
    {
        "anchor": "Fixed point actions for SU(3) gauge theory: We summarize our recent work on the construction and properties of fixed\npoint (FP) actions for lattice $SU(3)$ pure gauge theory. These actions have\nscale invariant instanton solutions and their spectrum is exact through\n1--loop, i.e. in their physical predictions there are no $a^n$ nor $g^2 a^n$\ncut--off effects for any $n$. We present a few-parameter approximation to a\nclassical FP action which is valid for short correlation lengths. We perform a\nscaling test of the action by computing the quantity $G = L \\sqrt{\\sigma(L)}$,\nwhere the string tension $\\sigma(L)$ is measured from the torelon mass $\\mu = L\n\\sigma(L)$, on lattices of fixed physical volume and varying lattice spacing\n$a$. While the Wilson action shows scaling violations of about ten per cent,\nthe approximate fixed point action scales within the statistical errors for $\n1/2 \\ge aT_c$.",
        "positive": "Gluon PDF of the proton using twisted mass fermions: In this paper, we present lattice QCD results for the $x$-dependence of the\nunpolarized gluon PDF for the proton. We use one ensemble of $N_f=2+1+1$\nmaximally twisted mass fermions with a clover improvement, and the Iwasaki\nimproved gluon action. The quark masses are tuned to produce a pion with a mass\nof 260 MeV. The ensemble has a lattice spacing of $a=0.093$ fm and a spatial\nextent of 3 fm. We employ the pseudo-distribution approach, which relies on\nmatrix elements of non-local operators that couple to momentum-boosted hadrons.\nIn this work, we use five values of the momentum boost between 0 and 1.67 GeV.\nThe gluon field strength tensors of the non-local operator are connected with\nstraight Wilson lines of varying length $z$. The light-cone Ioffe time\ndistribution (ITD) is extracted utilizing data with $z$ up to 0.56 fm and a\nquadratic parametrization in terms of the Ioffe time at fixed values of $z$. We\nexplore systematic effects, such as the effect of the stout smearing for the\ngluon operator, excited states effects, and the dependence on the maximum value\nof $z$ entering the fits to obtain the gluon PDF. Also, for the first time, the\nmixing with the quark singlet PDFs is eliminated using matrix elements with\nnon-local quark operators that were previously analyzed within the quasi-PDF\nframework on the same ensemble. Here, we expand the data set for the quark\nsinglet and reanalyze within the pseudo-PDFs method eliminating the\ncorresponding mixing in the gluon PDF."
    },
    {
        "anchor": "Is SU(2) lattice gauge theory a spin glass?: A new order parameter is constructed for SU(2) lattice gauge theory in the\ncontext of the two-real-replica method normally used for spin glasses. The\norder parameter is sensitive to a global Z2 subgroup of the gauge symmetry\nwhich is seen to break spontaneously at $\\beta = 4/g^2 = 1.96\\pm 0.01$. No\ngauge fixing is required. Finite size scaling is consistent with a high-order\nparamagnet to spin glass transition with a critical exponent $\\nu = 0.99 \\pm\n0.13$. The existence of this transition suggests a second transition from spin\nglass to ferromagnet should exist at higher $\\beta$.",
        "positive": "Phase diagram and Debye mass in thermally reduced QCD: At temperatures well above the transition, QCD admits a thermally reduced\nversion in 3D, which reproduces the long distance physics. We analyze the phase\ndiagram, point out the relevance of Z(3) symmetry in the location of the\ntransition and suggest a way out to reconcile this with the data. Related to\nthis symmetry is the existence of an observable, the Z(N) wall, or rather its\n3D version, and discuss some of its advantages over other observables."
    },
    {
        "anchor": "On the Local Structure of Topological Charge Fluctuations in QCD: We consider the lattice topological charge density introduced by Hasenfratz,\nLaliena and Niedermayer and propose its eigenmode expansion as a tool to\ninvestigate the structure of topological charge fluctuations in QCD. The\nresulting effective density is built from local chiralities studied previously.\nAt every order of the expansion the density exactly sums up to the global\ntopological charge, and the leading term describes the maximally smooth\nspace-time distribution of charge relevant for propagating light fermions. We\nuse this framework to demonstrate our previous suggestion that the bulk of\ntopological charge in QCD does not effectively appear in the form of quantized\nunit lumps. Our conclusion implies that it is unlikely that the mixing of\n\"would-be\" zeromodes associated with such lumps is the prevalent microscopic\nmechanism for spontaneous chiral symmetry breaking in QCD. We also present\nfirst results quantitatively characterizing the space-time behavior of\neffective densities. For coherent fluctuations contained in spherical regions\nwe find a continuous distribution of associated charges essentially ending at\n~0.5.",
        "positive": "New lattice action for heavy quarks: We extend the Fermilab method for heavy quarks to include interactions of\ndimensions 6 and 7 in the action. There are, in general, many new interactions,\nbut we carry out the calculations needed to match the lattice action to\ncontinuum QCD at the tree level, finding six non-zero couplings. Using the\nheavy-quark theory of cutoff effects, we estimate how large the remaining\ndiscretization errors are. We find that our tree-level matching, augmented with\none-loop matching of the dimension-five interactions, can bring these errors\nbelow 1%, at currently available lattice spacings."
    },
    {
        "anchor": "Correct way to extract dominant part of the Wilson loop in higher\n  representations: The Abelian dominance for the string tension was shown for the fundamental\nsources in MA gauge in the lattice simulations. For higher representations,\nhowever, it is also known that the naive \"Abelian\" Wilson loop, which is\ndefined by using the diagonal part of the gauge field, does not reproduce the\ncorrect behavior. To solve this problem, for an arbitrary representation of an\narbitrary compact gauge group, we propose to redefine the \"Abelian\" Wilson\nloop. By using this redefined operator, we demonstrate the \"Abelian\" dominance\nfor sources in the adjoint representation and the sextet representation of\n$SU(3)$ gauge group in lattice simulations.",
        "positive": "Tadpole-improved SU(2) lattice gauge theory: A comprehensive analysis of tadpole-improved SU(2) lattice gauge theory is\nmade. Simulations are done on isotropic and anisotropic lattices, with and\nwithout improvement. Two tadpole renormalization schemes are employed, one\nusing average plaquettes, the other using mean links in Landau gauge.\nSimulations are done with spatial lattice spacings $a_s$ in the range of about\n0.1--0.4 fm. Results are presented for the static quark potential, the\nrenormalized lattice anisotropy $a_t/a_s$ (where $a_t$ is the ``temporal''\nlattice spacing), and for the scalar and tensor glueball masses. Tadpole\nimprovement significantly reduces discretization errors in the static quark\npotential and in the scalar glueball mass, and results in very little\nrenormalization of the bare anisotropy that is input to the action. We also\nfind that tadpole improvement using mean links in Landau gauge results in\nsmaller discretization errors in the scalar glueball mass (as well as in the\nstatic quark potential), compared to when average plaquettes are used. The\npossibility is also raised that further improvement in the scalar glueball mass\nmay result when the coefficients of the operators which correct for\ndiscretization errors in the action are computed beyond tree level."
    },
    {
        "anchor": "Correlated Dirac eigenvalues around the transition temperature on\n  $N_\u03c4=8$ lattices: We investigate the criticality of chiral phase transition manifested in the\nfirst and second order derivatives of Dirac eigenvalue spectrum with respect to\nlight quark mass in (2+1)-flavor lattice QCD. Simulations are performed at\ntemperatures from about 137 MeV to 176 MeV on $N_{\\tau}=8$ lattices using the\nhighly improved staggered quarks and the tree-level improved Symanzik gauge\naction. The strange quark mass is fixed to its physical value\n$m_s^{\\text{phy}}$ and the light quark mass is set to $m_s^{\\text{phy}}/40$\nwhich corresponds to a Goldstone pion mass $m_{\\pi}=110$ MeV. We find that in\ncontrast to the case at $T\\simeq 205$ MeV $m_l^{-1} \\partial \\rho(\\lambda,\nm_l)/\\partial m_l$ is no longer equal to $\\partial ^2\\rho(\\lambda,\nm_l)/\\partial m_l^2$ and $\\partial ^2\\rho(\\lambda, m_l)/\\partial m_l^2$ even\nbecomes negative at certain low temperatures. This means that as temperature\ngetting closer to $T_c$ $\\rho(\\lambda, m_l)$ is no longer proportional to\n$m_l^2$ and thus dilute instanton gas approximation is not valid for these\ntemperatures. We demonstrate the temperature dependence can be factored out in\n$\\partial \\rho(\\lambda, m_l)/ \\partial m_l$ and $\\partial^2 \\rho(\\lambda, m_l)/\n\\partial m_l^2$ at $T \\in [137, 153]$ MeV, and then we propose a feasible\nmethod to estimate the power $c$ given $\\rho \\propto m_l^{c}$.",
        "positive": "Gribov Copies in Lattice QCD: We have performed an exhaustive search for Gribov copies on the lattice and\ntheir possible dependence from finite temperature effects. We show that, for\neach value of lattice size, Gribov copies are dense in configuration space at\nlow temperature but their density tend to lower when the temperature increases.\nWe have investigated lattice sizes running from $16^3\\times 8$ to $16^4$."
    },
    {
        "anchor": "The complete lowest order chiral Lagrangian from a little box: We recently performed a pilot study determining the parameters of the leading\norder chiral Lagrangian from distributions of the eigenvalues of a quenched\nDirac operator coupled to an imaginary isospin chemical potential. We\ncomplement a quick survey of our recent preprint arXiv:0708.1731 [hep-lat] by\naddressing some points raised during discussions at the conference.",
        "positive": "Structural Properties of the Lattice Heavy Quark Effective Theory: We discuss two related aspects of the lattice version of the heavy quark\neffective theory (HQET). They are the effects of heavy quark modes with large\nmomenta, near the boundary of the Brillouin zone, and the renormalization of\nthe lattice HQET. We argue that even though large momentum modes are present,\ntheir contributions to heavy-light bound states and perturbative loop integrals\nare dynamically suppressed and vanish in the continuum limit. We also discuss a\nnew feature of the renormalization of the lattice HQET not present in the\ncontinuum theory, namely that the classical velocity is finitely renormalized."
    },
    {
        "anchor": "Unpolarized proton PDF at NNLO from lattice QCD with physical quark\n  masses: We present a lattice QCD calculation of the unpolarized isovector quark\nparton distribution function (PDF) of the proton utilizing a perturbative\nmatching at next-to-next-to-leading-order (NNLO). The calculations are carried\nout using a single ensemble of gauge configurations generated with $N_f = 2 +\n1$ highly-improved staggered quarks with physical masses and a lattice spacing\nof $a = 0.076$ fm. We use one iteration of hypercubic smearing on these gauge\nconfigurations, and the resulting smeared configurations are then used for all\naspects of the subsequent calculation. For the valence quarks, we use the\nWilson-clover action with physical quark masses. We consider several methods\nfor extracting information on the PDF. We first extract the lowest four Mellin\nmoments using the leading-twist operator product expansion approximation. Then,\nwe determine the $x$ dependence of the PDF through a deep neural network within\nthe pseudo-PDF approach and additionally through the framework of\nlarge-momentum effective theory utilizing a hybrid renormalization scheme. This\nis the first application of the NNLO matching coefficients for the nucleon\ndirectly at the physical point.",
        "positive": "Quenched Light Hadron Mass Spectrum and Decay Constants: the effects of\n  $O(a)$-Improvement at $\u03b2=6.2$: We compare the light hadron spectrum and decay constants for quenched QCD at\n$\\beta=6.2$ using an $O(a)$-improved nearest-neighbour Wilson fermion action\nwith those obtained using the standard Wilson fermion action on the same set of\n18 gauge configurations. For pseudoscalar meson masses in the range\n330--800~MeV, we find no significant difference between the results for the two\nactions. The scales obtained from the string tension and mesonic sector are\nconsistent, but differ from that derived from baryon masses. The ratio of the\npseudoscalar decay constant to the vector meson mass increases slowly with\nquark mass as observed experimentally."
    },
    {
        "anchor": "Effective Lagrangian for strongly coupled domain wall fermions: We derive the effective Lagrangian for mesons in lattice gauge theory with\ndomain-wall fermions in the strong-coupling and large-N_c limits. We use the\nformalism of supergroups to deal with the Pauli-Villars fields, needed to\nregulate the contributions of the heavy fermions. We calculate the spectrum of\npseudo-Goldstone bosons and show that domain wall fermions are doubled and\nmassive in this regime. Since we take the extent and lattice spacing of the\nfifth dimension to infinity and zero respectively, our conclusions apply also\nto overlap fermions.",
        "positive": "Determination of Lattice QCD Equation of state at a finite chemical\n  potential: Exponential resummation to all orders in $\\mu_B$ is a promising scheme which\ncan capture contributions to all orders in $\\mu_B$ by considering only the\nfirst few Taylor coefficients in the Taylor expansion of thermodynamic\nobservables in lattice QCD. This approach however, gets affected by biased\nestimates of $n$-point correlation functions $D_n$ whose effects can\nsignificantly hinder probe of finite density QCD. We present an unbiased\nexponential resummation formalism, which can reproduce the Taylor series up to\nthe desired order in $\\mu_B$, besides retaining the original form of the\nall-order resummation estimate of QCD partition function."
    },
    {
        "anchor": "Poisson Statistics in the High Temperature QCD Dirac Spectrum: At low temperature in the epsilon regime of QCD the low-end of the Dirac\nspectrum is described by random matrix theory. In contrast, there has been no\nsimilarly well established staistical description in the high temperature,\nchirally symmetric phase. Using lattice simulations we show that at high\ntemperature a band of extremely localized eigenmodes appear at the low-end of\nthe Dirac spectrum. The corresponding eigenvalues are statistically independent\nand obey a generalized Poisson distribution. Higher up in the spectrum the\nPoisson distribution rapidly crosses over into the bulk distribution predicted\nby the random matrix ensemble with the corresponding symmetry. Our results are\nbased on quenched lattice simulations with the overlap and the staggered Dirac\noperator done well above the critical temperature at several volumes and values\nof $N_t$. We also discuss the crucial role played by the fermionic boundary\ncondition and the Polyakov-loop in this phenomenon.",
        "positive": "Flux tube counting or Casimir scaling: QCD confines quarks in all representations. From lattice calculations and fat\ncenter vortices model, we discuss that the coefficient of the linear term in\nthe potential is proportional to both casimir scaling and the number of\nfundamental strings."
    },
    {
        "anchor": "What the lattice can tell us about nucleon structure: This review focuses on the current status of lattice calculations of three\nobservables which are both phenomenologically and experimentally relevant and\nhave been scrutinized recently. These three observables are the nucleon\nelectromagnetic form factors, the momentum fraction, <x>, and the nucleon axial\ncoupling, gA.",
        "positive": "Vacuum alignment and lattice artifacts: Wilson fermions: Confinement in asymptotically free gauge theories is accompanied by the\nspontaneous breaking of the global flavor symmetry. If a subgroup of the flavor\nsymmetry group is coupled weakly to additional gauge fields, the vacuum state\ntends to align such that the gauged subgroup is unbroken. Independently, a\nlattice discretization of the continuum theory typically reduces the manifest\nflavor symmetry, and, in addition, can give rise to new lattice-artifact phases\nwith spontaneously broken symmetries. Here, we study the interplay of these two\nphenomena for Wilson fermions, using chiral lagrangian techniques. We consider\ntwo examples: electromagnetic corrections to QCD, and a prototype\ncomposite-Higgs model."
    },
    {
        "anchor": "Rectangular Wilson Loops at Large N: This work is about pure Yang-Mills theory in four Euclidean dimensions with\ngauge group SU(N). We study rectangular smeared Wilson loops on the lattice at\nlarge N and relatively close to the large-N transition point in their\neigenvalue density. We show that the string tension can be extracted from these\nloops but their dependence on shape differs from the asymptotic prediction of\neffective string theory.",
        "positive": "Geometry of percolating monopole clusters: We perform detailed measurements of the geometrical characteristics of the\npercolating cluster of the magnetic monopole currents in the confining phase of\nthe lattice SU(2) gluodynamics. The Maximal Abelian projection is used to\ndefine the monopoles. The use of the geometrical language is motivated by\nrecent observations that the full non-Abelian action associated with the\nmonopoles corresponds to point-like particles on the currently available\nlattices. Scaling behavior of various quantities is observed."
    },
    {
        "anchor": "Almost Gauge Invariant Lattice Actions for Chiral Gauge Theories, using\n  Laplacian Gauge Fixing: It is described how to obtain an almost gauge invariant lattice action $S$\nfor chiral gauge theories, or other models in which a straightforward\ndiscretization leads to a lattice action $S^\\pr$ in which gauge invariance is\nbroken. The lattice action is `almost' gauge invariant, because a local gauge\ntransformation leaves the action the same, up to a global gauge transformation.\nIn this approach the action $S$ for all gauge fields on a gauge orbit is the\nsame as that of the action $S^\\pr$ evaluated for the gauge field fixed to a\nsmooth gauge. To define $S$ unambiguously, it must be possible to compute the\ngauge fixed field unambiguously. This rules out gauge conditions which suffer\nfrom Gribov ambiguities but it can be achieved by using the recently proposed\nLaplacian gauge. When using the almost gauge invariant action $S$ in a\nnumerical simulation, it is not necessary to fix the gauge, and hence gauge\nfixing terms and Fadeev-Popov ghosts are not required. A hybrid Monte Carlo\nalgorithm for simulations with this new action is described and tested on a\nsimple toy model.",
        "positive": "The Running Coupling from SU(3) Potentials: From an accurate determination of the inter-quark potential, one can study\nthe running coupling constant for a range of $R$-values and hence estimate the\nscale $\\Lambda_{\\overline{\\rm MS}}$. Detailed results are presented for $SU(3)$\npure gauge theory from a study of a $36^4$ lattice at $\\beta=6.5$. (to appear\nin Proceedings of Lattice 1992 - Amsterdam)"
    },
    {
        "anchor": "Valence parton distribution of pion from lattice QCD: Approaching\n  continuum: We present a high-statistics lattice QCD determination of the valence parton\ndistribution function (PDF) of the pion, with a mass of 300 MeV, using two very\nfine lattice spacings of $a=0.06$ fm and 0.04 fm. We reconstruct the\n$x$-dependent PDF, as well as infer the first few even moments of the PDF using\nleading-twist 1-loop perturbative matching framework. Our analyses use both\nRI-MOM and ratio-based schemes to renormalize the equal-time bi-local\nquark-bilinear matrix elements of pions boosted up to 2.4 GeV momenta. We use\nvarious model-independent and model-dependent analyses to infer the large-$x$\nbehavior of the valence PDF. We also present technical studies on lattice\nspacing and higher-twist corrections present in the boosted pion matrix\nelements.",
        "positive": "Decay of rho and a1 mesons on the lattice using distillation: We extract the P-wave pi-pi phase shift for five values of pion relative\nmomenta, which gives information on the rho resonance. The Breit-Wigner formula\ndescribes the pi-pi phase shift dependence nicely and we extract\nm(rho)=792(7)(8) MeV and the coupling g_{\\rho\\pi\\pi}=5.13(20) at our mpi=266\nMeV. We extract the P-wave scattering length a_{l=1}^{\\pi\\pi}=0.082(10)(3) fm^3\nfrom the state with the lowest pion relative momenta.\n  We also determine the S-wave rho-pi phase shift for two values of relative\nmomenta, which provides parameters of the lowest axial resonance a1(1260).\nUsing the Breit-Wigner fit we extract m(a1)=1.44(4) GeV and the coupling\ng_{a_1\\rho\\pi}=1.1(3) GeV. From the lowest state we also extract the rho-pi\nscattering length a_{l=0}^{\\rho\\pi}=0.23(12) fm for our mpi.\n  The simulation is performed using one Nf=2 ensemble of gauge configurations\nwith clover-improved Wilson quarks. The phase shifts are determined from the\nlowest two energy-levels, which are obtained by the variational analysis with a\nnumber of quark-antiquark and meson-meson interpolators. The correlation\nfunctions are calculated using the distillation method with the Laplacian\nHeaviside (LapH) smearing of quarks."
    },
    {
        "anchor": "Many flavor approach to study the nature of chiral phase transition of\n  two-flavor QCD: We perform lattice numerical simulations to study the phase transition of QCD\nat finite temperature to clarify the nature of the transition of massless two\nflavor QCD. We investigate QCD with two light and Nf heavy quarks instead of\ntwo-flavor QCD, and focus on the light quark mass dependence of the critical\nheavy mass, below which the transition is of first order. The heavy quarks are\nincorporated into two flavor configurations in the form of the hopping\nparameter expansion through the reweighting technique. The nature of the\ntransition is identified by the shape of the constraint effective potential at\nthe critical temperature. Our result indicates that the critical heavy mass\nremains finite in the chiral limit of the two flavors, suggesting the phase\ntransition of massless two-flavor QCD is of second order.",
        "positive": "The 't Hooft-Veneziano limit of the Polyakov loop models: The broad class of U(N) and SU(N) Polyakov loop models on the lattice are\nsolved exactly in the combined large N, Nf limit, where N is a number of colors\nand Nf is a number of quark flavors, and in any dimension. In this 't\nHooft-Veneziano limit the ratio N/Nf is kept fixed. We calculate both the free\nenergy and various correlation functions. The critical behavior of the models\nis described in details at finite temperatures and non-zero baryon chemical\npotential. Furthermore, we prove that the calculation of the N-point (baryon)\ncorrelation function reduces to the geometric median problem in the confinement\nphase. In the deconfinement phase we establish an existence of the complex\nmasses and an oscillating decay of correlations in a certain region of\nparameters."
    },
    {
        "anchor": "B_K with dynamical overlap fermions: We report on a calculation of $B_K$ with two-flavor dynamical overlap\nfermions on a $16^3 \\times 32$ lattice at $a\\sim 0.12$ fm. The results are\ncompared with the PQChPT prediction of quark mass dependence. The systematic\nerrors due to finite volume effects and fixing topology are discussed.",
        "positive": "Convergence of the chiral expansion in two-flavor lattice QCD: We test the convergence property of the chiral perturbation theory (ChPT)\nusing a lattice QCD calculation of pion mass and decay constant with two\ndynamical quark flavors. The lattice calculation is performed using the overlap\nfermion formulation, which realizes exact chiral symmetry at finite lattice\nspacing. By comparing various expansion prescriptions, we find that the chiral\nexpansion is well saturated at the next-to-leading order (NLO) for pions\nlighter than $\\sim$450 MeV. Better convergence behavior is found in particular\nfor a resummed expansion parameter $\\xi$, with which the lattice data in the\npion mass region 290$\\sim$750 MeV can be fitted well with the\nnext-to-next-to-leading order (NNLO) formulae. We obtain the results in\ntwo-flavor QCD for the low energy constants $\\bar{l}_3$ and $\\bar{l}_4$ as well\nas the pion decay constant, the chiral condensate, and the average up and down\nquark mass."
    },
    {
        "anchor": "Chiral transition in a strongly coupled fermion-gauge-scalar model: We report the recent results from the computer simulations of a\nfermion-gauge-scalar model with dynamical chiral-symmetry breaking and chiral\ntransition induced by the scalar field. This model might be considered to be a\npossible alternative to the Higgs mechanism of mass generation. A new scheme is\ndeveloped for detecting the chiral transition. Our results show with higher\nprecision than the earlier works that the chiral transition line joins the\nHiggs phase transition line, separating the Higgs and Nambu (chiral-symmetry\nbreaking) phases. The end point of the Higgs transition with divergent\ncorrelation lengths is therefore suitable for an investigation of the continuum\nlimit.",
        "positive": "The QCD Spectrum: Recent results in light hadron spectroscopy are reviewed. Attention is given\nto the requirements of precision determinations in lattice gauge theory.\nDifferent methods for extracting the running coupling constant $\\alpha_S$ are\ncompared. Some recent results in determining the nature of the interaction\nbetween static quarks are also discussed."
    },
    {
        "anchor": "Non-Abelian vortex in lattice gauge theory: We perform the Monte Carlo study of the SU(3) non-Abelian Higgs model. We\ndiscuss phase structure and non-Abelian vortices by gauge invariant operators.\nExternal magnetic fields induce non-Abelian vortices in the color-flavor locked\nphase. The spatial distribution of non-Abelian vortices suggests the repulsive\nvortex-vortex interaction.",
        "positive": "Screening in (2+1)D pure gauge theory at high temperatures: We compute heavy quark potentials in pure gauge $SU(3)$ at high temperatures\nin $2+1$ dimensions and confront them with expectations emerging from\nperturbative calculations."
    },
    {
        "anchor": "Topological susceptibility in 2+1 flavors lattice QCD with domain-wall\n  fermions: We measure the topological charge and its fluctuation for the gauge\nconfigurations generated by the RBC and UKQCD Collaborations using 2+1 flavors\nof domain-wall fermions on the 16^3 x 32 lattice (L \\simeq 2 fm) with length 16\nin the fifth dimension at inverse lattice spacing a^{-1} \\simeq 1.62 GeV. From\nthe spectral flow of the Hermitian operator H_w (2 + \\gamma_5 H_w)^{-1}, we\nobtain the topological charge Q_t of each gauge configuration in the three\nensembles with light sea quark masses m_q a = 0.01, 0.02, and 0.03, and with\nthe strange quark mass fixed at m_s a = 0.04. From our result of Q_t, we\ncompute the topological susceptibilty \\chi_t = < Q_t^2 > /volume. In the small\nm_q regime, our result of \\chi_t agrees with the chiral effective theory. Using\nthe formula \\chi_t = \\Sigma / (m_u^{-1} + m_d^{-1} + m_s^{-1}) by\nLeutwyler-Smilga, we obtain the chiral condensate \\Sigma^MSbar(2 GeV) =\n[259(6)(9) MeV]^3.",
        "positive": "Strongly Interacting Higgs Sector without Technicolor: Simulation results are presented on Higgs mass calculations in the\nspontaneously broken phase of the Higgs sector in the minimal Standard Model\nwith a higher derivative regulator. A heavy Higgs particle is found in the TeV\nmass range in the presence of a complex conjugate ghost pair at higher\nenergies. The ghost pair evades easy experimental detection. As a finite and\nunitary theory in the continuum, this model serves as an explicit and simple\nexample of a strongly interacting Higgs sector without technicolor."
    },
    {
        "anchor": "An numerical approach for finite volume three-body interaction: In present work, we study an numerical approach to one dimensional finite\nvolume three-body interaction, the method is demonstrated by considering a toy\nmodel of three spinless particles interacting with pair-wise $\\delta$-function\npotentials. The numerical results are compared with the exact solutions of\nthree spinless bosons interaction when strength of short-range interactions are\nset equal for all pairs.",
        "positive": "Global Anomalies in chiral gauge theories on the lattice: We discuss the issue of global anomalies in chiral gauge theories on the\nlattice. In Luscher's approach, these obstructions make it impossible to define\nconsistently a fermionic measure for the path integral. We show that an SU(2)\ntheory has such a global anomaly if the Weyl fermion is in the fundamental\nrepresentation. The anomaly in higher representations is also discussed. We\nfinally show that this obstruction is the lattice analogue of the SU(2) anomaly\nfirst discovered by Witten."
    },
    {
        "anchor": "Vector current renormalisation in momentum subtraction schemes using the\n  HISQ action: As the only lattice vector current that does not require renormalisation is\nthe point-split conserved current it is convenient to have a robust, precise\nand computationally cheap methodology for the calculation of vector current\nrenormalisation factors, $Z_V$. Momentum subtraction schemes, such as RI-SMOM,\nimplemented nonperturbatively on the lattice provide such a method if it can be\nshown that the systematic errors, e.g. from condensates, are well controlled.\n  We present $Z_V$ calculations for the conserved current in both the RI-SMOM\nand RI$'$-MOM momentum subtraction schemes as well as local current\nrenormalisation in the RI-SMOM scheme. By performing these calculations at\nvarious values of the momentum scale $\\mu$ and different lattice spacings we\ncan investigate the presence of power suppressed nonperturbative contributions\nand compare the results to expectations arising from the Ward-Takahashi\nidentity. Our results show that the RI-SMOM scheme provides a well controlled\ndetermination of $Z_V$ but the standard RI$'$-MOM scheme does not.\n  We then present some preliminary uses of these $Z_V$ calculations in charm\nphysics.",
        "positive": "Testing dynamic stabilisation in complex Langevin simulations: Complex Langevin methods have been successfully applied in theories that\nsuffer from a sign problem such as QCD with a chemical potential. We present\nand illustrate a novel method (dynamic stabilisation) that ensures that Complex\nLangevin simulations stay close to the SU(3) manifold, which lead to correct\nand improved results in the framework of pure Yang-Mills simulations and QCD in\nthe limit of heavy quarks."
    },
    {
        "anchor": "Analytical continuation from imaginary to real chemical potential in\n  2-color QCD under scrutiny: The method of analytical continuation from imaginary to real chemical\npotential is tested in 2-color QCD. In comparison to previous studies in the\nsame theory, an exact updating algorithm is used and simulations are performed\ncloser to the thermodynamic limit. It is shown that the method considerably\nimproves if suitable functions are used to interpolate data with imaginary\nchemical potential.",
        "positive": "Tensor network analysis of critical coupling in two dimensional\n  $\u03c6^{4}$ theory: We make a detailed analysis of the spontaneous $Z_{2}$-symmetry breaking in\nthe two dimensional real $\\phi^{4}$ theory with the tensor renormalization\ngroup approach, which allows us to take the thermodynamic limit easily and\ndetermine the physical observables without statistical uncertainties. We\ndetermine the critical coupling in the continuum limit employing the tensor\nnetwork formulation for scalar field theories proposed in our previous paper.\nWe obtain $\\left[ \\lambda / \\mu_{\\mathrm{c}}^{2} \\right]_{\\mathrm{cont.}} =\n10.913(56)$ with the quartic coupling $\\lambda$ and the renormalized critical\nmass $\\mu_{\\mathrm{c}}$. The result is compared with previous results obtained\nby different approaches."
    },
    {
        "anchor": "Classification of Minimally Doubled Fermions: We propose a method to control the number of species of lattice fermions\nwhich yields new classes of minimally doubled lattice fermions. We show it is\npossible to control the number of species by handling $O(a)$ Wilson-term-like\ncorrections in fermion actions, which we will term ``Twisted-ordering Method\".\nUsing this method we obtain new minimally doubled actions with one exact chiral\nsymmetry and exact locality. We classify the known minimally doubled fermions\ninto two types based on the locations of the propagator poles in the Brillouin\nzone.",
        "positive": "Nontrivial Fixed Point in the 4D $\u03a6^4$ Lattice Model with Internal\n  $O(N)$ Symmetry: It is shown that the infinite dimensional critical surface of general\neuclidean lattice actions in a generic four-dimensional scalar field theory\nwith $\\Phi^4$ interactions has a domain of special multicritical points where\nhigher dimensional operators play a special role. Renormalized trajectories of\nhigher derivative continuum field theories with nontrivial interactions are\ntraced back to special ultraviolet stable fixed points on the manifold of\nmulticritical points. These fixed points have an infinite number of relevant\ndirections which identify the universality classes of critical higher\nderivative field theories. The relevance of the new fixed point structure is\ndiscussed within the context of the triviality Higgs mass bound."
    },
    {
        "anchor": "Electromagnetic effects on topological observables in QCD: In this proceedings article we present a selected set of our lattice results\nregarding the effect that background electromagnetic fields have on the\ntopology of QCD. In particular, we report on the lattice spacing-dependence of\nthe axion-photon coupling as well as on the response of the topological\nsusceptibility to strong magnetic fields at nonzero temperatures. We\ndemonstrate that the ratio of topological susceptibilities at finite to zero\nmagnetic field has a well behaved continuum limit at low temperatures using a\nreweighting technique. Moreover, we study the scaling of the axion-photon\ncoupling towards the continuum limit and show that it is less severely affected\nby discretisation effects.",
        "positive": "Two-Dimensional Seven-State Potts Model Under External Magnetic Field: The two-dimensional Potts Model with seven states under external field is\nstudied using a cluster algorithm. Cluster size distribution and the\nfluctuations in the average cluster size provide helpful information on the\norder of phase transitions."
    },
    {
        "anchor": "Monopoles, confinement and the photon propagator in QED$_3$: We study the lattice gauge boson propagator of 3D compact QED in Landau gauge\nat zero and non-zero temperature. Non-perturbative effects are reflected by the\ngeneration of a mass $m$, by an anomalous dimension $\\alpha$ and by the photon\nwave function renormalisation $Z$. These effects can be attributed to\nmonopoles: they are absent in the propagator of the regular part of the gauge\nfield. The r\\^ole of Gribov copies is carefully investigated.",
        "positive": "Confinement and center vortices in Coulomb gauge: analytic and numerical\n  results: We review the confinement scenario in Coulomb gauge. We show that when thin\ncenter vortex configurations are gauge transformed to Coulomb gauge, they lie\non the common boundary of the fundamental modular region and the Gribov region.\nThis unifies elements of the Gribov confinement scenario in Coulomb gauge and\nthe center-vortex confinement scenario. We report on recent numerical studies\nwhich support both of these scenarios."
    },
    {
        "anchor": "Dilaton chiral perturbation theory and applications: We review dilaton chiral perturbation theory (dChPT), the effective\nlow-energy theory for the light sector of near-conformal, confining theories.\ndChPT provides a systematic expansion in both the fermion mass and the distance\nto the conformal window. It accounts for the pions and the light scalar, the\napproximate Nambu-Goldstone bosons for chiral and scale symmetry, respectively.\nA unique feature of dChPT is the existence of a large-mass regime in which the\ntheory exhibits approximate hyperscaling, while the expansion nevertheless\nremains systematic. We discuss applications to lattice data, presenting\nsuccesses as well as directions for future work.",
        "positive": "Vacuum Stability and the Higgs Boson: The discovery of the Higgs boson at the LHC, and especially the determination\nof its mass around 125 GeV, together with the absence of any trace of new\nphysics make it conceivable that we live in a metastable (but long-lived)\nelectroweak vacuum. I will describe the state-of-the-art calculation that leads\nto this conclusion, elaborate on possible implications as well as cures of this\ninstability of the Higgs potential and discuss some possible lines of attack\nfor lattice studies of such metastability."
    },
    {
        "anchor": "A status update on the determination of $\u039b_{\\overline{\\rm\n  MS}}^{N_{\\rm f}=3}$ by the ALPHA collaboration: The ALPHA collaboration aims to determine $\\alpha_s(m_Z)$ with a total error\nbelow the percent level. A further step towards this goal can be taken by\ncombining results from the recent simulations of 2+1-flavour QCD by the CLS\ninitiative with a number of tools developed over the years: renormalized\ncouplings in finite volume schemes, recursive finite size techniques, two-loop\nrenormalized perturbation theory and the (improved) gradient flow on the\nlattice. We sketch the strategy, which involves both the standard SF coupling\nin the high energy regime and a gradient flow coupling at low energies. This\nimplies the need for matching both schemes at an intermediate switching scale,\n$L_{\\rm swi}$, which we choose roughly in the range 2-4 GeV. In this\ncontribution we present a preliminary result for this matching procedure, and\nwe then focus on our almost final results for the scale evolution of the SF\ncoupling from $L_{\\rm swi}$ towards the perturbative regime, where we extract\nthe $N_{\\rm f} = 3$ ${\\Lambda}$-parameter, ${\\Lambda}_{\\overline{\\rm\nMS}}^{N_{\\rm f}=3}$, in units of $L_{\\rm swi}$ . Connecting $L_{\\rm swi}$ and\nthus the ${\\Lambda}$-parameter to a hadronic scale such as $F_K$ requires 2\nfurther ingredients: first, the connection of $L_{\\rm swi}$ to $L_{\\rm max}$\nusing a few steps with the step-scaling function of the gradient flow coupling,\nand, second, the continuum extrapolation of $L_{\\rm max} F_K$.",
        "positive": "From Perturbation Theory to Confinement: How the String Tension is built\n  up: We study the spatial volume dependence of electric flux energies for SU(2)\nYang-Mills fields on the torus with twisted boundary conditions. The results\napproach smoothly the rotational invariant Confinement regime. The would-be\nstring tension is very close to the infinite volume result already for volumes\nof $(1.2 \\ {\\rm fm.})^3$. We speculate on the consequences of our result for\nthe Confinement mechanism."
    },
    {
        "anchor": "Grand Canonical Potential for a Static Quark-Antiquark Pair at finite\n  chemical potential: The grand canonical potential for a static quark-antiquark pair at\nnon-vanishing chemical potential was determined at several temperatures. The\ndynamical staggered simulations were carried out with 2+1 physical quarks along\nthe Lines of Constant Physiscs (LCP).",
        "positive": "Breakdown of large-N quenched reduction in SU(N) lattice gauge theories: We study the validity of the large-N equivalence between four-dimensional\nSU(N) lattice gauge theory and its momentum quenched version--the Quenched\nEguchi-Kawai (QEK) model. We find that the assumptions needed for the proofs of\nequivalence do not automatically follow from the quenching prescription. We use\nweak-coupling arguments to show that large-N equivalence is in fact likely to\nbreak down in the QEK model, and that this is due to dynamically generated\ncorrelations between different Euclidean components of the gauge fields. We\nthen use Monte-Carlo simulations at intermediate couplings with 20 <= N <= 200\nto provide strong evidence for the presence of these correlations and for the\nconsequent breakdown of reduction. This evidence includes a large discrepancy\nbetween the transition coupling of the \"bulk\" transition in lattice gauge\ntheories and the coupling at which the QEK model goes through a strongly\nfirst-order transition. To accurately measure this discrepancy we adapt the\nrecently introduced Wang-Landau algorithm to gauge theories."
    },
    {
        "anchor": "Spectroscopy of the BSM sextet model: As part of our ongoing lattice study of SU(3) gauge theory with two flavors\nof fermions in the two-index symmetric representation (the sextet model), we\npresent the current status of the pseudoscalar particle spectrum. We use a\nmixed action approach based on the gradient flow to control lattice artifacts,\nallowing a simultaneous extrapolation to the chiral and continuum limits. We\nfind strong evidence that the pseudoscalar is a Goldstone boson state, with\nspontaneously broken chiral symmetry and a non-zero Goldstone decay constant in\nthe chiral limit. In agreement with our study of the gauge coupling $\\beta$\nfunction, we find the sextet model appears to be a near-conformal gauge theory\nand serves as a prototype of the composite Higgs BSM template.",
        "positive": "Vector screening masses in the quark-gluon plasma and their physical\n  significance: Static and non-static thermal screening states that couple to the conserved\nvector current are investigated in the high-temperature phase of QCD. Their\nmasses and couplings to the current are determined at weak coupling, as well as\nusing two-flavor lattice QCD simulations. A consistent picture emerges from the\ncomparison, providing evidence that non-static Matsubara modes can indeed be\ntreated perturbatively. We elaborate on the physical significance of the\nscreening masses."
    },
    {
        "anchor": "Improved Landau Gauge Fixing and Discretisation Errors: Lattice discretisation errors in the Landau gauge condition are examined. An\nimproved gauge fixing algorithm in which order a^2 errors are removed is\npresented. Order a^2 improvement of the gauge fixing condition displays the\nsecondary benefit of reducing the size of higher-order errors. These results\nemphasise the importance of implementing an improved gauge fixing condition.",
        "positive": "Glauber dynamics of phase transitions: SU(3) lattice gauge theory: Motivated by questions about the QCD deconfining phase transition, we studied\nin two previous papers Model A (Glauber) dynamics of 2D and 3D Potts models,\nfocusing on structure factor evolution under heating (heating in the gauge\ntheory notation, i.e., cooling of the spin systems). In the present paper we\nset for 3D Potts models (Ising and 3-state) the scale of the dynamical effects\nby comparing to equilibrium results at first and second order phase transition\ntemperatures, obtained by re-weighting from a multicanonical ensemble. Our\nfinding is that the dynamics entirely overwhelms the critical and non-critical\nequilibrium effects.\n  In the second half of the paper we extend our results by investigating the\nGlauber dynamics of pure SU(3) lattice gauge on $N_{\\tau} N_{\\sigma}^3$\nlattices directly under heating quenches from the confined into the deconfined\nregime. The exponential growth factors of the initial response are calculated,\nwhich give Debye screening mass estimates. The quench leads to competing vacuum\ndomains of distinct $Z_3$ triality, which delay equilibration of pure gauge\ntheory forever, while their role in full QCD remains a subtle question. As in\nspin systems we find for pure SU(3) gauge theory a dynamical growth of\nstructure factors, reaching maxima which scale approximately with the volume of\nthe system, before settling down to equilibrium. Their influence on various\nobservables is studied and different lattice sizes are simulated to illustrate\nan approach to a finite volume continuum limit. Strong correlations are found\nduring the dynamical process, but not in the deconfined phase at equilibrium."
    },
    {
        "anchor": "Isospin-0 $\u03c0\u03c0$ scattering from twisted mass lattice QCD: We present results for the isospin-0 $\\pi\\pi$ s-wave scattering length\ncalculated in twisted mass lattice QCD. We use three $N_f = 2$ ensembles with\nunitary pion mass at its physical value, 240~MeV and 330~MeV respectively. We\nalso use a large set of $N_f = 2 + 1 +1$ ensembles with unitary pion masses\nvarying in the range of 230~MeV - 510~MeV at three different values of the\nlattice spacing. A mixed action approach with the Osterwalder-Seiler action in\nthe valence sector is adopted to circumvent the complications arising from\nisospin symmetry breaking of the twisted mass quark action. Due to the\nrelatively large lattice artefacts in the $N_f = 2 + 1 +1$ ensembles, we do not\npresent the scattering lengths for these ensembles. Instead, taking the\nadvantage of the many different pion masses of these ensembles, we\nqualitatively discuss the pion mass dependence of the scattering properties of\nthis channel based on the results from the $N_f = 2 + 1 +1$ ensembles. The\nscattering length is computed for the $N_f = 2$ ensembles and the chiral\nextrapolation is performed. At the physical pion mass, our result $M_\\pi\na^\\mathrm{I=0}_0 = 0.198(9)(6)$ agrees reasonably well with various\nexperimental measurements and theoretical predictions.",
        "positive": "Charmed baryons on the lattice: We discuss the significance of charm baryon spectroscopy in hadron physics\nand review the recent developments of the spectra of charmed baryons in lattice\ncalculations. Special emphasis is given on the recent studies of highly excited\ncharm baryon states. Recent precision lattice measurements of the low lying\ncharm and bottom baryons are also reviewed."
    },
    {
        "anchor": "Lattice supersymmetry with Hopf algebra for the link approach: A formalism of lattice supersymmetry based on a lattice-deformed superalgebra\nwhich was originally introduced in the link approach formulation is presented.\nWe propose that the superalgebra can in fact be identified as a Hopf algebra,\nshowing all the Hopf algebra axioms and consistencies are satisfied with\nexplicit formulae. In particular, the \"deformed\" Leibniz rules proposed in the\noriginal link approach are now built in the coproduct structure of the Hopf\nalgebra. Fields in this scheme, as representations of the Hopf algebra, are\nfound to obey a kind of mildly deformed statistics, which is interpreted as a\nbraiding strucutre. We can then construct, at least perturbatively, the\ncorresponding lattice field theory, which has the Hopf algebraic symmetry with\nthe deformed statistics, as an example of braided quantumm field theory\nformulated by Oeckl.",
        "positive": "Generalization capabilities of translationally equivariant neural\n  networks: The rising adoption of machine learning in high energy physics and lattice\nfield theory necessitates the re-evaluation of common methods that are widely\nused in computer vision, which, when applied to problems in physics, can lead\nto significant drawbacks in terms of performance and generalizability. One\nparticular example for this is the use of neural network architectures that do\nnot reflect the underlying symmetries of the given physical problem. In this\nwork, we focus on complex scalar field theory on a two-dimensional lattice and\ninvestigate the benefits of using group equivariant convolutional neural\nnetwork architectures based on the translation group. For a meaningful\ncomparison, we conduct a systematic search for equivariant and non-equivariant\nneural network architectures and apply them to various regression and\nclassification tasks. We demonstrate that in most of these tasks our best\nequivariant architectures can perform and generalize significantly better than\ntheir non-equivariant counterparts, which applies not only to physical\nparameters beyond those represented in the training set, but also to different\nlattice sizes."
    },
    {
        "anchor": "Large-volume results in SU(2) with adjoint fermions: Taming finite-volume effects is a crucial ingredient in order to identify the\nexistence of IR fixed points. We present the latest results from our numerical\nsimulations of SU(2) gauge theory with 2 Dirac fermions in the adjoint\nrepresentation on large volumes. We compare with previous results, and\nextrapolate to thermodynamic limit when possible.",
        "positive": "On the Phase Structure of the Schwinger Model with Wilson Fermions: We study the phase structure of the massive one flavour lattice Schwinger\nmodel on the basis of the finite size scaling behaviour of the partition\nfunction zeroes. At $\\beta = 0$ we observe and discuss a possible discrepancy\nwith results obtained by a different method."
    },
    {
        "anchor": "Renormalization of lattice gauge theories with massless Ginsparg Wilson\n  fermions: Using functional techniques, we prove, to all orders of perturbation theory,\nthat lattice vector gauge theories with Ginsparg Wilson fermions are\nrenormalizable. For two or more massless fermions, they satisfy a flavour\nmixing axial vector Ward identity. It involves a lattice specific part that is\nquadratic in the vertex functional and classically irrelevant. We show that it\nstays irrelevant under renormalization. This means that in the continuum limit\nthe (standard) chiral symmetry becomes restored. In particular, the flavour\nmixing current does not require renormalization.",
        "positive": "$T$-matrix Analysis of Static Wilson Line Correlators from Lattice QCD\n  at Finite Temperature: We utilize a previously constructed thermodynamic $T$-matrix approach to the\nquark-gluon plasma (QGP) to calculate Wilson line correlators (WLCs) of a\nstatic quark-antiquark pair and apply them to the results from 2+1-flavor\nlattice-QCD (lQCD) computations with realistic pion mass. The self-consistent\n$T$-matrix results, which include constraints from the lQCD equation of state\nin the light-parton sector, can describe the lQCD data for WLCs fairly well\nonce refinements of the input parameters are implemented. In particular, the\ninput potential requires less screening than used in previous $T$-matrix\nanalyses. Pertinent predictions for the spectral and transport properties of\nthe QGP are discussed, including the spatial diffusion coefficient for heavy\nquarks which turns out to have a rather weak temperature dependence, in\napproximate agreement with recent lQCD results."
    },
    {
        "anchor": "Statistical QCD with non-positive measure: In this talk we discuss the microscopic limit of QCD at nonzero chemical\npotential. In this domain, where the QCD partition function is under complete\nanalytical control, we uncover an entirely new link between the spectral\ndensity of the Dirac operator and the chiral condensate: violent complex\noscillations on the microscopic scale give rise to the discontinuity of the\nchiral condensate at zero quark mass. We first establish this relation exactly\nwithin a random matrix framework and then analyze the importance of the\nindividual modes by Fourier analysis.",
        "positive": "Quantum chaos in supersymmetric QCD at finite density: We investigate the distribution of the spacings of adjacent eigenvalues of\nthe lattice Dirac operator. At zero chemical potential $\\mu$, the\nnearest-neighbor spacing distribution $P(s)$ follows the Wigner surmise of\nrandom matrix theory both in the confinement and in the deconfinement phase.\nThis is indicative of quantum chaos. At nonzero chemical potential, the\neigenvalues of the Dirac operator become complex and we discuss how $P(s)$ can\nbe defined in the complex plane. Numerical results from an SU(2) simulation\nwith staggered fermions in fundamental and adjoint representations are compared\nwith predictions from non-hermitian random matrix theory, and agreement with\nthe Ginibre ensemble is found for $\\mu\\approx 0.5$."
    },
    {
        "anchor": "Perturbative and non-perturbative studies of the SU(2)-Higgs model on\n  lattices with asymmetric lattice spacings: We present a calculation of the O(g^2,\\lambda) perturbative corrections to\nthe coupling anisotropies of the SU(2)-Higgs model on lattices with asymmetric\nlattice spacings. These corrections are obtained by a one-loop calculation\nrequiring the rotational invariance of the gauge and Higgs boson propagators in\nthe continuum limit. The coupling anisotropies are also determined from\nnumerical simulations of the model on appropriate lattices. The one-loop\nperturbation theory and the simulation results agree with high accuracy. It is\ndemonstrated that rotational invariance is also restored for the static\npotential determined from space-space and space-time Wilson loops.",
        "positive": "Calculation of Moments of Structure Functions: The progress on the lattice computation of low moments of both the\nunpolarised and polarised nucleon structure functions is reviewed with\nparticular emphasis on continuum and chiral extrapolations and comparison\nbetween quenched and unquenched fermions."
    },
    {
        "anchor": "Charm Degrees of Freedom in Quark Gluon Plasma: Lattice QCD studies on fluctuations and correlations of charm quantum number\nhave established that deconfinement of charm degrees of freedom sets in around\nthe chiral crossover temperature, $T_c$, i.e. charm degrees of freedom carrying\nfractional baryonic charge start to appear. By reexamining those same lattice\nQCD data we show that, in addition to the contributions from quark-like\nexcitations, the partial pressure of charm degrees of freedom may still contain\nsignificant contributions from open-charm meson and baryon-like excitations\nassociated with integral baryonic charges for temperatures up to $1.2~ T_c$.\nCharm quark-quasiparticles become the dominant degrees of freedom for\ntemperatures $T>1.2~ T_c$.",
        "positive": "Hadron structure from lattice quantum chromodynamics: This is a review of hadron structure physics from lattice QCD. Throughout\nthis report, we place emphasis on the contribution of lattice results to our\nunderstanding of a number of fundamental physics questions related to, e.g.,\nthe origin and distribution of the charge, magnetization, momentum and spin of\nhadrons. Following an introduction to some of the most important hadron\nstructure observables, we summarize the methods and techniques employed for\ntheir calculation in lattice QCD. We briefly discuss the status of relevant\nchiral perturbation theory calculations needed for controlled extrapolations of\nthe lattice results to the physical point. In the main part of this report, we\ngive an overview of lattice calculations on hadron form factors, moments of\n(generalized) parton distributions, moments of hadron distribution amplitudes,\nand other important hadron structure observables. Whenever applicable, we\ncompare with results from experiment and phenomenology, taking into account\nsystematic uncertainties in the lattice computations. Finally, we discuss\npromising results based on new approaches, ideas and techniques, and close with\nremarks on future perspectives of the field."
    },
    {
        "anchor": "Chiral Phase Transition in Lattice QCD with Wilson Quarks: The nature of the chiral phase transition in lattice QCD is studied for the\ncases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice\nwith the temporal direction extension $N_t=4$. We find that the chiral phase\ntransition is continuous for the case of 2 flavors, while it is of first order\nfor 3 and 6 flavors.",
        "positive": "Classical limit theorems and high entropy MIXMAX random number generator: We investigate the interrelation between the distribution of stochastic\nfluctuations of independent random variables in probability theory and the\ndistribution of time averages in deterministic Anosov C-systems. On the one\nhand, in probability theory, our interest dwells on three basic topics: the\nlaws of large numbers, the central limit theorem and the law of the iterated\nlogarithm for sequences of real-valued random variables. On the other hand we\nhave chaotic, uniformly hyperbolic Anosov C-systems defined on tori which have\nmixing of all orders and nonzero Kolmogorov entropy. These extraordinary\nergodic properties of deterministic Anosov C-systems ensure that the above\nclassical limit theorems for sums of independent random variables in\nprobability theory are fulfilled by the time averages for the sequences\ngenerated by the C-systems. The MIXMAX generator of pseudorandom numbers\nrepresents the C-system for which the classical limit theorems are fulfilled."
    },
    {
        "anchor": "Non Perturbative QCD: This series of lectures consists of two parts. In the first part the\nfoundations of perturbative and non perturbative formulation are discussed. The\nambiguity in the definition of vacuum condensates is then analyzed. In the\nsecond part the symmetry patterns of the deconfining phase transition are\ndiscussed.",
        "positive": "Variational method for lattice spectroscopy with ghosts: We discuss the variational method used in lattice spectroscopy calculations.\nIn particular we address the role of ghost contributions which appear in\nquenched or partially quenched simulations and have a non-standard euclidean\ntime dependence. We show that the ghosts can be separated from the physical\nstates. Our result is illustrated with numerical data for the scalar meson."
    },
    {
        "anchor": "Monopole effects on Polyakov loop and its gauge independence in QCD: Monte-Carlo simulations of abelian projection in $T \\neq 0$ pure lattice QCD\nshow that\n  1)\\ Polyakov loops written in terms of abelian link fields alone play a role\nof an order parameter of deconfinement transition\n  2)\\ the abelian Polyakov loops are decomposed into contributions from Dirac\nstrings of monopoles and from photons\n  3)\\ vanishing of the abelian Polyakov loops in the confinement phase is due\nto the Dirac strings alone and the photons give a finite contribution in both\nphases.\n  Moreover, these results appear to hold good in unitary gauges. This suggests\nthat monopole condensation as the color confinement mechanism is gauge\nindependent.",
        "positive": "Topography of the cooled $\\cal{O}(3)$ vacuum: We investigate the {\\it topography\\/} of the \\o3 vacuum after various degrees\nof under-relaxed cooling, using the na\\\"{\\i}ve action density and geometric and\nfield theoretical definitions of the topological charge density. The results\nare presented graphically. (This is a cutdown version of the full paper which\nis available via anonymous ftp to suna.amtp.liv.ac.uk in /pub/pss/. The figures\nmissing from this version are available from the same site.)"
    },
    {
        "anchor": "Continuum Thermodynamics of the GluoN_c Plasma: We study the thermodynamics of SU(N_c) pure gauge theories for N_c=3, 4 and\n6. The continuum and thermodynamic limits of bulk quantities such as the\npressure, energy density and the entropy density are taken by using several\ndifferent lattice spacings and volumes. There is no window of temperature in\nwhich a non-trivial conformal theory describes bulk thermodynamics. We extract\nthe latent heat of the first-order deconfinement phase transitions and observe\ngood scaling with N_c. For all quantities that we measure, strong N_c scaling\nholds, except, possibly, very close to the transition temperature, T_c; however\nwe are unable to find strong evidence for scaling with the 't Hooft coupling in\nthermal quantities at the small values of N_c which we study.",
        "positive": "Optimising creation operators for charmonium spectroscopy on the lattice: Smearing the bare quantum fields in lattice calculations before applying\ncomposite hadron creation operators has a long record of substantially\nimproving overlaps onto low-lying energy eigenstates. A technique called\ndistillation which defines smearing for quark fields as a low-rank linear\nprojection operator into a small vector space of smooth gauge-covariant fields\nhas proven to be both effective and versatile in hadron spectroscopy\ncalculations albeit with significant computational cost . In this paper, more\ngeneral operators in this space of smooth fields are introduced and optimised,\nwhich enhances the performance of the method when tested on systems of heavy\nquark-anti-quark pairs close to the charmonium energy scale."
    },
    {
        "anchor": "Lattice QCD with fixed topology: The overlap Dirac operator, which satisfies the Ginsparg-Wilson relation,\nrealizes exact chiral symmetry on the lattice without any unphysical doubler\nmodes. To perform the path integrals, one should, however, note that the\noverlap fermion determinant has discontinuities where the topology is\nill-defined, its locality is doubtful, and the numerical cost is suddenly\nenhanced.\n  An interesting solution would be to concentrate on a fixed topological sector\nin the full configuration space. In this thesis, we test a gauge action which\nautomatically satisfies Luescher's admissibility condition, as well as an\nadditional (large) negative mass Wilson fermion action in the quenched study\n(with no light quark). Both of them would keep the topology along the HMC\nsimulations. The quark potential and the topology stability are investigated\nwith different lattice sizes and different couplings.\n  The results of quenched QCD in the $\\epsilon$-regime are also presented as an\nexample of the lattice studies with fixed topology. Remarkable quark mass and\ntopology dependences of meson correlators allow us to determine the fundamental\nparameters of the effective theory, in which the exact chiral symmetry with the\nGinsparg Wilson relation plays a crucial role.",
        "positive": "Monte Carlo Simulations of the SU(2) Vacuum Structure: Lattice Monte Carlo simulations are performed for the SU(2) Yang Mills gauge\ntheory in the presence of an Abelian background with external sources to obtain\ninformation on the effective potential. The goal is to investigate the lowest\nLandau mode that, in the continuum one-loop effective potential, is the crucial\nmode for instability. It is shown that also in the lattice formulation this\nlowest Landau mode plays a very peculiar role, and it is important for the\nunderstanding of the vacuum properties."
    },
    {
        "anchor": "Large-N reduction with two adjoint Dirac fermions: We study the single site SU(N) lattice gauge theory with N_f=2 adjoint Wilson\nfermions for values of N up to 53. We determine the phase diagram of the theory\nas a function of the hopping parameter kappa and the inverse 't Hooft coupling\nb, searching for the region in which the Z_N^4 center symmetry is unbroken. In\nthis region the theory is equivalent to the infinite volume theory when N goes\nto infinity. We find a region of values of kappa on both sides of kappa_c for\nwhich the symmetry is unbroken, including both light physical quarks and masses\n~O(1/a). This is surrounded by a region with a complicated sequence of\npartially broken phases. We calculate Wilson loop expectation values and find\nthat using N <= 53 it is possible to extract the heavy-quark potential at small\ndistances (1-3 links) but not at longer distances. For this, larger values of\nN, or lattices with more sites, are needed.",
        "positive": "Correlated Instanton Orientations in the SU(2) Yang-Mills Vacuum and\n  Pair Formation in the Deconfined Phase: Using the renormalization group motivated smoothing technique we study the\nsemiclassical structure of the pure Yang-Mills vacuum. We carefully check that\nidentified clusters of topological charge behave like instantons around their\ncenters. Looking at distance distributions of clusters we find\ninstanton-antiinstanton pair formation in the deconfined phase. We use suitably\nnormalized gauge invariant field strength correlators to obtain first\nquantitative information on the relative color orientation of instantons. We\ngive further evidence for a modified instanton profile in the confined phase\nand present a simple alternative model for it."
    },
    {
        "anchor": "Up and down quark masses and corrections to Dashen's theorem from\n  lattice QCD and quenched QED: We present a determination of the corrections to Dashen's theorem and of the\nindividual up and down quark masses from a lattice calculation based on\nquenched QED and $N_f=2+1$ QCD simulations with 5 lattice spacings down to\n0.054 fm. The simulations feature lattice sizes up to 6 fm and average up-down\nquark masses all the way down to their physical value. For the parameter which\nquantifies violations to Dashens's theorem we obtain $\\epsilon=0.73(2)(5)(17)$,\nwhere the first error is statistical, the second is systematic, and the third\nis an estimate of the QED quenching error. For the light quark masses we\nobtain, $m_u=2.27(6)(5)(4) \\, MeV$ and $m_d=4.67(6)(5)(4) \\, MeV$ in the\n$\\overline{MS}$ scheme at $2 \\, GeV$ and the isospin breaking ratios\n$m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and\n$Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong\nCP problem by more than 24 standard deviations.",
        "positive": "Magnetic susceptibility and equation of state of N_f = 2+1 QCD with\n  physical quark masses: We determine the free energy of strongly interacting matter as a function of\nan applied constant and uniform magnetic field. We consider N_f = 2+1 QCD with\nphysical quark masses, discretized on a lattice by stout improved staggered\nfermions and a tree level improved Symanzik pure gauge action, and explore\nthree different lattice spacings. For magnetic fields of the order of those\nproduced in non-central heavy ion collisions (eB ~ 0.1 GeV^2) strongly\ninteracting matter behaves like a medium with a linear response, and is\nparamagnetic both above and below the deconfinement transition, with a\nsusceptibility which steeply rises in the deconfined phase. We compute the\nequation of state, showing that the relative increase in the pressure due to\nthe magnetic field gets larger around the transition, and of the order of 10 %\nfor eB ~ 0.1 GeV^2."
    },
    {
        "anchor": "The partition function of gauge supersymmetric Ising model on 3D regular\n  lattice: The partition function (quantum transition amplitude) of the gauge system\nwith gauge group $Z_2$ coupled with Majorana fermions is calculated on the\nregular 3D cubic lattice.",
        "positive": "Recent Results of Multimagnetical Simulations of the Ising Model: To investigate order-order interfaces, we perform multimagnetical Monte Carlo\nsimulations of the $2D$ and $3D$ Ising model. Stringent tests of the numerical\nmethods are performed by reproducing with high precision exact $2D$ results. In\nthe physically more interesting $3D$ case we estimate the amplitude $F^s_0$ of\nthe critical interfacial tension."
    },
    {
        "anchor": "Flux tubes in $N_f=2+1$ QCD with external magnetic fields: We study the behavior of the confining flux tube in $N_f=2+1$ QCD at the\nphysical point, discretized with the stout smearing improved staggered quark\naction and the tree level Symanzik gauge action. We discuss how it depends on a\nuniform external magnetic field, showing how it displays anisotropies with\nrespect to the magnetic field direction. Moreover, we compare the observed\nanisotropy pattern with that of the static quark-antiquark potential we\nobtained in our previous works.",
        "positive": "Multi-nucleon bound states in $N_f=2+1$ lattice QCD: We report on our on-going effort to calculate the properties of light nuclei\ndirectly from quarks and gluons based on lattice QCD. After briefly introducing\nour motivations and aims, we describe our strategy of fixing the strange quark\nmass at its physical value and approaching the physical point for the up and\ndown quark masses step by step from the region of heavy quark masses. A\nsuccessful calculation for the pion mass of 0.51GeV is reviewed, and the status\nfor a lighter pion mass of 0.30GeV is reported."
    },
    {
        "anchor": "Finite-Volume Corrections to Electromagnetic Masses for\n  Larger-Than-Physical Electric Charges: The numerical value of the fine-structure constant generally leads to small\nisospin-breaking effects due to electromagnetism in QCD. This smallness\ncomplicates determining isospin breaking from lattice QCD computations that\ninclude electromagnetism. One solution to this problem consists of performing\ncomputations using larger-than-physical values of the electric charge, and\nsubsequently extrapolating (or interpolating) to the physical value of the\nfine-structure constant. Motivated by recent lattice QCD + QED computations of\nelectromagnetic masses employing this setup, we consider finite-volume effects\narising from the use of larger-than-physical electric charges. A modified\npower-counting scheme, which is based on treating the fine-structure constant\nas larger than its physical value, is explored. Results for perturbative QED\ncorrections, however, are surprising. Within the framework of non-relativistic\nQED, multi-loop diagrams exhibit a momentum factorization property that\nproduces exact cancellations. We determine that power-law finite-volume effects\nvanish at the leading two- and three-loop order, as well as the next-to-leading\ntwo-loop order. For larger-than-physical charges, we consequently expect no\nappreciable volume corrections beyond leading-order QED.",
        "positive": "2+1 flavor QCD with the fixed point action in the $\u03b5$-regime: We generated configurations with the approximate fixed-point Dirac operator\n$D_\\mathrm{FP}$ on a $12^4$ lattice with $a \\approx 0.13 $fm where the scale\nwas set by $r_0$. The distributions of the low lying eigenvalues in different\ntopological sectors were compared with those of the Random Matrix Theory which\nleads to a prediction of the chiral condensate."
    },
    {
        "anchor": "Do Wilson Fermions Induce an Adjoint Gauge Coupling?: Expansions of the Wilson determinant in lattice QCD with quarks produce gauge\naction terms which shift the coupling constant of the fundamental\nrepresentation plaquette action and induce an adjoint representation plaquette\naction. We study the magnitude of these induced couplings with two flavors of\nWilson fermions. We utilize a microcanonical demon method, which allows us to\nmeasure the induced couplings directly from gauge configurations generated by\nfull fermionic simulations.",
        "positive": "Coupling Constant and Quark Loop Expansion for Corrections to the\n  Valence Approximation: For full QCD vacuum expectation values we construct an expansion in quark\nloop count and in powers of a coupling constant. The leading term in this\nexpansion is the valence (quenched) approximation vacuum expectation value.\nHigher terms give corrections to the valence approximation. A test of the\nexpansion is presented for moderately heavy quarks on a small lattice. We\nconsider briefly an application of the expansion to quarkonium-glueball mixing."
    },
    {
        "anchor": "The Pseudoscalar Meson Mass to Two Loops in Three-Flavor Partially\n  Quenched $\u03c7$PT: This paper presents a first study of the pseudoscalar meson masses to two\nloops, or NNLO, within the supersymmetric formulation of partially quenched\nchiral perturbation theory (PQ$\\chi$PT). The expression for the pseudoscalar\nmeson mass in the case of three valence and three sea quarks with equal masses,\nbut different from each other, is given to ${\\cal O}(p^6)$, along with a\nnumerical analysis.",
        "positive": "The Tetraquark Candidate Zc(3900) from Dynamical Lattice QCD Simulations: The structure of the tetraquark candidate $Z_{c}(3900)$, which was\nexperimentally reported in $e^+ e^-$ collisions, is studied by the s-wave\nmeson-meson coupled-channel scattering on the lattice. The s-wave interactions\namong the $\\pi J/\\psi$, $\\rho \\eta_{c}$ and $D \\bar{D}^{*}$ channels are\nderived from (2+1)-flavor dynamical QCD simulations at $m_{\\pi}=410$--$700$\nMeV. It is found that the interactions are dominated by the off-diagonal $\\pi\nJ/\\psi$-$D \\bar{D}^{*}$ and $\\rho \\eta_{c}$-$D \\bar{D}^{*}$ couplings. With the\ninteractions obtained, the s-wave two-body amplitudes and the pole position in\nthe $\\pi J/\\psi$-$\\rho \\eta_{c}$-$D \\bar{D}^{*}$ coupled-channel scattering are\ncalculated. The results show that the $Z_{c}(3900)$ is not a conventional\nresonance but a threshold cusp. A semiphenomenological analysis with the\ncoupled-channel interaction to the experimentally observed decay mode is also\npresented to confirm the conclusion."
    },
    {
        "anchor": "Non-perturbative quark mass renormalisation and running in $N_f=3$ QCD: We determine from first principles the quark mass anomalous dimension in Nf=3\nQCD between the electroweak and hadronic scales. This allows for a fully\nnon-perturbative connection of the perturbative and non-perturbative regimes of\nthe Standard Model in the hadronic sector. The computation is carried out to\nhigh accuracy, employing massless O(a)-improved Wilson quarks and finite-size\nscaling techniques. We also provide the matching factors required in the\nrenormalisation of light quark masses from lattice computations with\nO(a)-improved Wilson fermions and a tree-level Symanzik improved gauge action.\nThe total uncertainty due to renormalisation and running in the determination\nof light quark masses in the SM is thus reduced to about 1%.",
        "positive": "Generalized ensemble algorithm for U(1) gauge theory: Hybrid Monte Carlo simulations of the pure compact U(1) gauge theory are\nperformed with the Tsallis weight. The simulations show that the use of the\nTsallis weight enhances the tunneling rate between metastable states."
    },
    {
        "anchor": "Spectroscopy of two dimensional N=2 Super Yang Mills theory: Albeit the standard model is the most successful model of particles physics,\nit still has some theoretical shortcomings, for instance the hierarchy problem,\nthe absence of dark matter, etc. Supersymmetric extensions of the standard\nmodel could be a possible solution to these problems. One of the building\nblocks of these supersymmetric models are supersymmetric gauge theories. It is\nexpected that they exhibit interesting features like confinement, chiral\nsymmetry breaking, magnetic monopoles and the like. We present new results on\nN=2 Super Yang Mills theory in two dimensions. The lattice action is derived by\na dimensional reduction of the N=1 Super Yang Mills theory in four dimensions.\nBy preserving the R symmetry of the four dimensional model we can exploit Ward\nidentities to fine tune our parameters of the model to obtain the chiral and\nsupersymmetric continuum limit. This allows us to calculate the mass spectrum\nat the physical point and compare these results with effective field theories.",
        "positive": "Charmonium Potentials At Non-Zero Temperature: The charmonium potential at non-zero temperature has been studied using gauge\nconfigurations with anisotropic lattices and 2+1 dynamical flavors of light sea\nquarks. We use the HAL QCD time-dependent method developed for the study of\nnucleon-nucleon potentials. To serve as in-put, local-extended charmonium\ncorrelators were calculated. The results are consistent with the expectation\nthat the potential between heavy quarks should become deconfining at high\ntemperatures."
    },
    {
        "anchor": "Testing trivializing maps in the Hybrid Monte Carlo algorithm: We test a recent proposal to use approximate trivializing maps in a field\ntheory to speed up Hybrid Monte Carlo simulations. Simulating the CP^{N-1}\nmodel, we find a small improvement with the leading order transformation, which\nis however compensated by the additional computational overhead. The scaling of\nthe algorithm towards the continuum is not changed. In particular, the effect\nof the topological modes on the autocorrelation times is studied.",
        "positive": "The flavour singlet mesons in QCD: We study the flavour singlet mesons from first principles using lattice QCD.\nWe explore the splitting between flavour singlet and non-singlet for vector and\naxial mesons as well as the more commonly studied cases of the scalar and\npseudoscalar mesons."
    },
    {
        "anchor": "Finite density 2d O(3) sigma model: dualization and numerical\n  simulations: The action of the 2d O(3) non-linear sigma model on the lattice in a bath of\nparticles, when expressed in terms of standard O(3) degrees of freedom, is\ncomplex. A reformulation of the model in terms of new variables that makes the\naction real is presented. This reshaping enables us to utilize Monte Carlo\nsimulations based on usual importance sampling. Several observables, including\nthe correlation function and the mass gap, are measured.",
        "positive": "Extraction of bare Form Factors for $\\mathrm B_\\mathrm s \\to \\mathrm K\n  \\ell \u03bd$ Decays in non-perturbative HQET: We discuss the extraction of the ground state $\\langle \\mathrm{K} ({\\bf\np})|V_\\mu(0)|\\mathrm{B} ({\\bf 0})\\rangle$ matrix elements from Euclidean\nlattice correlation functions. The emphasis is on the elimination of excited\nstate contributions. Two typical gauge-field ensembles with lattice spacings\n$0.075, \\; 0.05$ fm and pion masses $330,\\;270$ MeV are used from the O($a$)-\nimproved CLS 2-flavour simulations and the final state momentum is $|{\\bf\np}|=0.5\\,{\\rm GeV}$. The b-quark is treated in HQET including the\n$1/m_\\mathrm{b}$ corrections. Fits to two-point and three-point correlation\nfunctions and suitable ratios including summed ratios are used, yielding\nconsistent results with precision of around 2% which is $not$ limited by the\n$1/m_\\mathrm{b}$ corrections but by the dominating static form factors. Excited\nstate contributions are under reasonable control but are the bottleneck towards\nprecision. We do not yet include a specific investigation of multi-hadron\ncontaminations, a gap in the literature which ought to be filled soon."
    },
    {
        "anchor": "Three-body spectrum in a finite volume: the role of cubic symmetry: The three-particle quantization condition is partially diagonalized in the\ncenter-of-mass frame by using cubic symmetry on the lattice. To this end,\ninstead of spherical harmonics, the kernel of the Bethe-Salpeter equation for\nparticle-dimer scattering is expanded in the basis functions of different\nirreducible representations of the octahedral group. Such a projection is of\nparticular importance for the three-body problem in the finite volume due to\nthe occurrence of three-body singularities above breakup. Additionally, we\nstudy the numerical solution and properties of such a projected quantization\ncondition in a simple model. It is shown that, for large volumes, these\nsolutions allow for an instructive interpretation of the energy eigenvalues in\nterms of bound and scattering states.",
        "positive": "QCD Hadron Spectroscopy with Staggered Dynamical Quarks at $\u03b2= 5.6$: We present preliminary results from the 1991 HEMCGC simulations with\nstaggered dynamical fermions on a $16^3 \\times 32$ lattice at $\\beta = 5.6$\nwith sea quark masses $am_q = 0.025$ and 0.01. The spectroscopy was done both\nfor staggered valence quarks with mass equal to the sea quark masses and for\nWilson valence quarks at six different values for $\\kappa$, 0.1320, 0.1410,\n0.1525, 0.1565, 0.1585, and 0.1600. In addition to the measurements performed\nin our earlier work, we also measured the $\\Delta$ and other `extended' hadrons\nfor staggered valence quarks and pseudo-scalar decay constants and vector meson\nmatrix elements, the wave function at the origin, for Wilson valence quarks."
    },
    {
        "anchor": "Study of Cluster Fluctuations in Two-dimensional q-State Potts Model: The two-dimensional Potts Model with 2 to 10 states is studied using a\ncluster algorithm to calculate fluctuations in cluster size as well as commonly\nused quantities like equilibrium averages and the histograms for energy and the\norder parameter. Results provide information about the variation of cluster\nsizes depending on the temperature and the number of states. They also give\nevidence for first-order transition when energy and the order parameter related\nmeasurables are inconclusive on small size lattices.",
        "positive": "Quark masses and strong coupling constant in 2+1 flavor QCD: We present a determination of the strange, charm and bottom quark masses as\nwell as the strong coupling constant in 2+1 flavor lattice QCD simulations\nusing highly improved staggered quark action. The ratios of the charm quark\nmass to the strange quark mass and the bottom quark mass to the charm quark\nmass are obtained from the meson masses calculated on the lattice and found to\nbe $m_c/m_s=11.871(91)$ and $m_b/m_c=4.528(57)$ in the continuum limit. We also\ndetermine the strong coupling constant and the charm quark mass using the\nmoments of pseudoscalar charmonium correlators: $\\alpha_s(\\mu=m_c)=0.3697(85)$\nand $m_c(\\mu=m_c)=1.267(12)$ GeV. Our result for $\\alpha_s$ corresponds to the\ndetermination of the strong coupling constant at the lowest energy scale so far\nand is translated to the value $\\alpha_s(\\mu=M_Z,n_f=5)=0.11622(84)$."
    },
    {
        "anchor": "Charmonium spectral functions in N_f=2 QCD at high temperature: Charmonium systems in two-flavour QCD at non-zero temperature are studied at,\nand above the deconfining transition. Using anisotropic lattices the MEM\napproach is used to extract spectral functions for these channels. By carefully\nvarying some of the irrelevant parameters in the MEM procedure, we confirm that\nour systematic effects are under control. The eta_c and J/psi states are found\nto persist at temperatures >~ 1.3 T_c in agreement with our previous dynamical\nstudies.",
        "positive": "Beauty Physics in Lattice Gauge Theory: We summarize the present status of lattice gauge theory computations of the\nleptonic decay constants $f_D$ and $f_B$. The various sources of systematic\nerrors are explained in a manner easily understood by the non--expert. The\nresults obtained by the different groups are then systematically compared. As a\nresult, we derive estimates for $f_D$ and $f_B$ in the quenched approximation\nthrough an appropriate combination of the data available from the different\ngroups. Since we account for a possible lattice spacing dependence, the final\nerrors are quite large. However, it is now well known how these uncertainties\ncan be reduced. For the decay constant of heavy--light pseudoscalar mesons with\nmasses of 1-2~GeV, an interesting comparison of a full QCD result with the\ncorresponding simulation in the quenched approximation can be done. Effects of\nsea quarks of mass $m_s$ are below the statistical accuracy of these\nsimulations. Related quantities, like $B$--parameters, the spectrum of\nbeauty--hadrons and the breaking of the QCD string are discussed briefly."
    },
    {
        "anchor": "Nucleon masses in strong magnetic fields: We compute the variation of the masses of the proton and the neutron induced\nby the presence of a strong external magnetic field. We discuss the choice of\nthe wave function and different techniques how to apply the magnetic field. The\nresults obtained from a 24 16^2 8 and a 16^2 8^2 lattice are compared with a\nphenomenological approach.",
        "positive": "OPE Analysis of QCD Potential and Determination of Lambda_MSbar: We analyze the static QCD potential in the distance region 0.1 fm < r < 1 fm.\nWe combine most recent lattice computations and perturbative computations of\nthe potential, in the framework of operator-product expansion (OPE). We\ndetermine simultaneously the non-perturbative contribution to the potential,\ndelta E_US(r), and the relation between the lattice scale (Sommer scale) and\nLambda_MSbar in the quenched approximation. We find that (1) large part of the\nshort-distance linear potential belongs to the perturbative Wilson coefficient,\n(2) delta E_US(r) =0 is disfavored, and (3) r_0 Lambda_MSbar^(3-loop)=0.574 +-\n0.042 . It provides a new method for precise determination of r_0 Lambda_MSbar."
    },
    {
        "anchor": "Lattice QCD at Non-Zero Temperature: This is a review of selected recent developments in finite-temperature\nlattice QCD. The focus is on the properties of the chiral crossover region,\ndeconfinement and fluctuations of conserved charges, the equation of state,\nproperties of heavy quarkonia and reconstruction of spectral functions.",
        "positive": "Determination of $m_c$ from $N_f = 2+1$ QCD with Wilson fermions: We present preliminary results for the charm quark mass in the $N_f=4$ RGI\nscheme. These were obtained using $N_f=2+1$ CLS ensembles with $\\mathcal{O}(a)$\nnon-perturbatively improved Wilson fermions. We employed five different lattice\nspacings, ranging down to $a\\lesssim 0.04$ fm and realized approximately\nphysical pion and kaon masses, with ensembles spread out along three different\ntrajectories in the quark mass plane, enabling a thorough study of the\ndependence on the lattice spacing and the light and strange sea quark masses.\nWe sketch our analysis strategy and find that the dominant errors at present\nare due to the renormalization and scale setting uncertainties."
    },
    {
        "anchor": "Hadronic property at finite density: We report on three topics on finite density simulations: (i) the derivative\nmethod for hadronic quantities, (ii) phase fluctuations in the vicinity of the\ncritical temperature and (iii) the density of states method at finite isospin\ndensity.",
        "positive": "Lattice QCD calculation of the pion charge radius using a\n  model-independent method: We use a method to calculate the hadron's charge radius without\nmodel-dependent momentum extrapolations. The method does not require the\nadditional quark propagator inversions on the twisted boundary conditions or\nthe computation of the momentum derivatives of quark propagators and thus is\neasy to implement. We apply this method to the calculation of pion charge\nradius $\\langle r_\\pi^2\\rangle$. For comparison, we also determine $\\langle\nr_\\pi^2\\rangle$ with the traditional approach of computing the slope of the\nform factors. The new method produces results consistent with those from the\ntraditional method and with statistical errors 1.5-1.9 times smaller. For the\nfour gauge ensembles at the physical pion masses, the statistical errors of\n$\\langle r_\\pi^2\\rangle$ range from 2.1% to 4.6% by using $\\lesssim50$\nconfigurations. For the ensemble at $m_\\pi\\approx 340$ MeV, the statistical\nuncertainty is even reduced to a sub-percent level."
    },
    {
        "anchor": "The Isgur-Wise function on the lattice: The h+, h_A1 form factors for the semi-leptonic B->D and B->D* decays are\nevaluated in quenched lattice QCD with beta=6.2. The action and the operators\nare fully O(a) non-perturbatively improved. The Isgur-Wise function is\nevaluated and fitted to extract its slope; the latter is found to be\nrho^2=1.1(2)(3) from the B->D* decay and rho^2=1.0(2)(3) from the B->D decay.\nThe form factors ratios R_1, R_2 are evaluated and found to be in agreement\nwith experimental determinations.",
        "positive": "Non-perturbative O(a) improvement of the SU(3) sextet model: We calculate non-perturbatively the coefficient c_sw required for O(a)\nimprovement of the SU(3) gauge theory with Nf = 2 fermions in the two-index\nsymmetric (sextet) representation. For the calculations we impose the standard\nimprovement condition in the Schr\\\"odinger functional framework, using two\ndifferent discretisations for the gauge field i.e. the Wilson plaquette action\nand the tree-level improved Symanzik (L\\\"uscher-Weisz) action."
    },
    {
        "anchor": "New term in effective field theory at fixed topology: A random matrix model for lattice QCD which takes into account the positive\ndefinite nature of the Wilson term is introduced. The corresponding effective\ntheory for fixed index of the Wilson Dirac operator is derived to next to\nleading order. It reveals a new term proportional to the topological index of\nthe Wilson Dirac operator and the lattice spacing. The new term appears\nnaturally in a fixed index spurion analysis. The spurion approach reveals that\nthe term is the first in a new family of such terms and that equivalent terms\nare relevant for the effective theory of continuum QCD.",
        "positive": "D-meson semileptonic decays to pseudoscalars from four-flavor lattice\n  QCD: We present lattice-QCD calculations of the hadronic form factors for the\nsemileptonic decays $D\\to\\pi\\ell\\nu$, $D\\to K\\ell\\nu$, and $D_s\\to K\\ell\\nu$.\nOur calculation uses the highly improved staggered quark (HISQ) action for all\nvalence and sea quarks and includes $N_f=2+1+1$ MILC ensembles with lattice\nspacings ranging from $a\\approx0.12$ fm down to $0.042$ fm. At most lattice\nspacings, an ensemble with physical-mass light quarks is included. The HISQ\naction allows all the quarks to be treated with the same relativistic\nlight-quark action, allowing for nonperturbative renormalization using partial\nconservation of the vector current. We combine our results with experimental\nmeasurements of the differential decay rates to determine\n$|V_{cd}|^{D\\to\\pi}=0.2238(11)^{\\rm Expt}(15)^{\\rm QCD}(04)^{\\rm EW}(02)^{\\rm\nSIB}[22]^{\\rm QED}$ and $|V_{cs}|^{D\\to K}=0.9589(23)^{\\rm Expt}(40)^{\\rm\nQCD}(15)^{\\rm EW}(05)^{\\rm SIB}[95]^{\\rm QED}$ This result for $|V_{cd}|$ is\nthe most precise to date, with a lattice-QCD error that is, for the first time\nfor the semileptonic extraction, at the same level as the experimental error.\nUsing recent measurements from BES III, we also give the first-ever\ndetermination of $|V_{cd}|^{D_s\\to K}=0.258(15)^{\\rm Expt}(01)^{\\rm\nQCD}[03]^{\\rm QED}$ from $D_s\\to K \\ell\\nu$. Our results also furnish new\nStandard Model calculations of the lepton flavor universality ratios\n$R^{D\\to\\pi}=0.98671(17)^{\\rm QCD}[500]^{\\rm QED}$, $R^{D\\to\nK}=0.97606(16)^{\\rm QCD}[500]^{\\rm QED}$, and $R^{D_s\\to K}=0.98099(10)^{\\rm\nQCD}[500]^{\\rm QED}$, which are consistent within $2\\sigma$ with experimental\nmeasurements. Our extractions of $|V_{cd}|$ and $|V_{cs}|$, when combined with\na value for $|V_{cb}|$, provide the most precise test of second-row CKM\nunitarity, finding agreement with unitarity at the level of one standard\ndeviation."
    },
    {
        "anchor": "Properties of the Fixed Point Lattice Dirac Operator in the Schwinger\n  Model: We present a numerical study of the properties of the Fixed Point lattice\nDirac operator in the Schwinger model. We verify the theoretical bounds on the\nspectrum, the existence of exact zero modes with definite chirality, and the\nIndex Theorem. We show by explicit computation that it is possible to find an\naccurate approximation to the Fixed Point Dirac operator containing only very\nlocal couplings.",
        "positive": "A Schur Complement Approach to Chiral Fermions: Lattice chiral fermions are synonymous to the Ginsparg-Wilson relation.\nIndeed, this relation is satisfied by the overlap, domain wall and perfect\naction fermion kernel.\n  In a recent work we have shown that it is possible to take a direct RG\napproach for fermions in the presence of gauge fields. This is due to an\nalgebraically implicit blocking technique which yields a Schur-complementary\ncoarse Dirac operator. Using a Schur complement approximation which is stable\nand regular, the scheme can be iterated to the fixed point.\n  In this talk, we elaborate more on the direct RG approach and show how to get\nhighly improved chiral fermions on the coarse lattice with the gauge fields\nremaining on the fine lattice. We give numerical examples in the case of\nlattice QCD using QCDLAB {\\tt http://phys.fshn.edu.al/qcdlab.html}"
    },
    {
        "anchor": "Analyzing the spectrum of general, non-hermitian Dirac operators: We discuss the computational problems when analyzing general, non-hermitian\nmatrices and in particular the un-modified Wilson lattice Dirac operator. We\nreport on our experiences with the Implicitly Restarted Arnoldi Method. The\neigenstates of the Wilson-Dirac operator which have real eigenvalues and\ncorrespond to zero modes in the continuum are analyzed by correlating the size\nof the eigenvalues with the chirality of the eigenstates.",
        "positive": "Partial Flavor Symmetry Restoration for Chiral Staggered Fermions: We study the leading discretization errors for staggered fermions by first\nconstructing the continuum effective Lagrangian including terms of O(a^2), and\nthen constructing the corresponding effective chiral Lagrangian. The terms of\nO(a^2) in the continuum effective Lagrangian completely break the SU(4) flavor\nsymmetry down to the discrete subgroup respected by the lattice theory. We\nfind, however, that the O(a^2) terms in the potential of the chiral Lagrangian\nmaintain an SO(4) subgroup of SU(4). It follows that the leading discretization\nerrors in the pion masses are SO(4) symmetric, implying three degeneracies\nwithin the seven lattice irreducible representations. These predictions hold\nalso for perturbatively improved versions of the action. These degeneracies are\nobserved, to a surprising degree of accuracy, in existing data. We argue that\nthe SO(4) symmetry does not extend to the masses and interactions of other\nhadrons (vector mesons, baryons, etc), nor to higher order in a^2. We show how\nit is possible that, for physical quark masses of O(a^2), the new SO(4)\nsymmetry can be spontaneously broken, leading to a staggered analogue of the\nAoki-phase of Wilson fermions. This does not, however, appear to happen for\npresently studied versions of the staggered action."
    },
    {
        "anchor": "Preliminary Study of B_K on 2+1 flavor DWF lattices from QCDOC: I present some preliminary calculations of B_K on 2+1 flavor domain-wall\nfermion lattices from the QCDOC, including a set of 16^3x32x8 lattices with\na^{-1} near 1.6 GeV. Although a final result awaits the production of a much\nlonger run, I will compare this preliminary value to previous results.",
        "positive": "Evidence for fractional topological charge in SU(2) pure Yang-Mills\n  theory: We investigate the spectral flows of the hermitian Wilson-Dirac operator in\nthe fundamental and adjoint representations on two ensembles of pure SU(2)\ngauge field configurations at the same physical volume. We find several\nbackground gauge field configurations where the index of the hermitian\nWilson-Dirac operator in the adjoint representation is not four times the index\nin the fundamental representation. This could imply a topological basis for the\ngluino condensate in supersymmetric Yang-Mills theories."
    },
    {
        "anchor": "Glueball masses with exponentially improved statistical precision: We briefly review the computational strategy we have recently introduced for\ncomputing glueball masses and matrix elements, which achieves an exponential\nreduction of statistical errors compared to standard techniques. The global\nsymmetries of the theory play a crucial role in the approach. We show how our\nprevious work on parity can be generalized to other symmetries. In particular\nwe discuss how to extract the mass of the 0++, 2++ and 0-+ lightest glueballs\navoiding the exponential degradation of the signal to noise ratio. We present\nnew numerical results and update the published ones.",
        "positive": "Lambda-parameter of lattice QCD with the overlap-Dirac operator: We compute the ratio $\\Lambda_L/\\Lambda_{\\bar{MS}}$ between the scale\nparameter $\\Lambda_L$, associated with a lattice formulation of QCD using the\noverlap-Dirac operator, and $\\Lambda_{\\bar{MS}}$ of the $\\bar{\\rm MS}$\nrenormalization scheme. To this end, the necessary one-loop relation between\nthe lattice coupling $g_0$ and the coupling renormalized in the $\\bar{{\\rm\nMS}}$ scheme is calculated, using the lattice background field technique."
    },
    {
        "anchor": "Fermion Interactions in the Wilson Yukawa Approach for Lattice Chiral\n  Gauge Theories: We consider fermion-gauge couplings in the Wilson-Yukawa approach for lattice\nchiral gauge theories. At the leading order of a fermionic hopping parameter\nexpansion we find that the fermion-gauge coupling has a chiral and tree-like\nstructure. We argue that this fermion-gauge coupling remains non-zero in the\ncontinuum limit taken in the Higgs phase. Possible fermion-scalar couplings in\nthis approach are considered. We also evaluate the fermion interaction with an\nexternal gauge field in the slightly modified model and show that it has a\nchiral structure in general.",
        "positive": "Quantum entanglement in SU(3) lattice Yang-Mills theory at zero and\n  finite temperatures: We examine the entanglement properties of the Yang-Mills theory by\ncalculating $\\alpha$ entanglement entropy with $\\alpha=2$ using a SU(3)\nquenched lattice gauge simulation both in the confinement and the deconfinement\nphases. In the confinement phase, the derivative of the $\\alpha$ entropy with\nrespect to the size $l$ of the subregion, whose entanglement properties are\ninterested in, scales as $1/l^3$, and a clear discontinuity cannot be found\nwithin our statistical errors. The $\\alpha$ entropy in the deconfinement phase\nsaturates at large $l$. The saturation value is comparable with the thermal\nentropy of the pure Yang-Mills theory, indicating that the $\\alpha$ entropy\nobeys the volume law at large $l$ in the deconfinement phase."
    },
    {
        "anchor": "On internal structure of the heavy-light mesons: We compute the radial distributions of the vector and axial charge density as\nwell as of the matter density in the heavy-light mesons on the lattice. The\nresults for the lowest lying static heavy-light mesons and their first excited\ncounterparts are obtained with Nf=2 dynamical quarks of Wilson (Clover) type\nand with the various improved static heavy quark actions. From these\ndistributions we were able to compute the corresponding charges and slopes of\nthe form factors (i.e. <r^2>). Those results are also presented, and briefly\ndiscussed too.",
        "positive": "Running coupling constant of background perturbation theory and lattice\n  interquark interaction: The conventional parametrizations of lattice static interquark force are\nshown to produce a mismatch of coupling constant near the matching point R_m\n\\approx 0.2 fm. The running coupling constant of the background perturbation\ntheory yields instead a selfconsistent description of lattice data over all\ninterval of distances, 0.05 fm \\la R \\la 1.1.fm, and is an analytic function\nwith the property of asymptotic freedom at small R and it is freezing at large\nR."
    },
    {
        "anchor": "QCD chiral Lagrangian on the lattice, strong coupling expansion and Ward\n  identities with Wilson fermions: We discuss a general strategy to compute the coefficients of the QCD chiral\nLagrangian using lattice QCD with Wilson fermions. This procedure requires the\nintroduction of a lattice chiral Lagrangian as an intermediate step in the\ncalculation. The QCD chiral Lagrangian is then obtained by expanding the\nlattice effective theory in increasing powers of the lattice spacing and the\nexternal momenta. In order to investigate the consequences of the chiral\nsymmetry breaking induced by the Wilson term, we study the lattice chiral\nLagrangian at the leading order of the strong coupling and large $N$ expansion.\nWe show that the effects of the Wilson term can be conveniently taken into\naccount, in the lattice effective theory, by a suitable renormalization\nprocedure. In particular, we show that, at the leading order of the strong\ncoupling and large N expansion, the chiral symmetry is exactly recovered on the\nlattice provided that the bare quark mass and the lattice operators are\nproperly renormalized.",
        "positive": "Nucleon isovector charges from physical mass domain-wall QCD: Systematics in nucleon isovector vector, $g_V$, and axialvector, $g_A$,\ncharges calculated on a 2+1-flavor dynamical domain-wall-fermions (DWF)\nensemble at physical mass jointly generated by RIKEN-BNL-Columbia (RBC) and\nUKQCD Collaborations with lattice cut off of 1.730(4) GeV, are analyzed. Both\nare calculated with about a percent or less statistical errors. A few\nstandard-deviation systematics seen in vector charge is consistent with\npossible $O(a^2)$ discretization error through small excited-state\ncontamination. Axialvector charge is found with three to nine\nstandard-deviation systematic deficit, compared with experiments, depending on\ncalculation methods."
    },
    {
        "anchor": "Supersymmetric gauge theories on the lattice: The perspectives of numerical simulations in supersymmetric quantum field\ntheories with vector-like gauge symmetries are discussed. A numerical\nsimulation algorithm for SU(2) gauge theory with gluinos is studied and the\nfirst results on the glueball-gluinoball spectrum are presented.",
        "positive": "Supersymmetry breaking on the lattice: the N=1 Wess-Zumino model: We discuss spontaneous supersymmetry breaking in the N=1 Wess-Zumino model in\ntwo dimensions on the lattice using Wilson fermions and the fermion loop\nformulation. In that formulation the fermion sign problem related to the\nvanishing of the Witten index can be circumvented and the model can be\nsimulated very efficiently using the recently introduced open fermion string\nalgorithm. We present first results for the supersymmetry breaking phase\ntransition and sketch the preliminary determination of a renormalised critical\ncoupling in the continuum limit."
    },
    {
        "anchor": "Lattice QCD and Baryon-Baryon Interactions: In this chapter, the current status on baryon-baryon interactions such as\nnuclear forces in lattice Quantum ChromoDynamics (QCD) is reviewed. In studies\nof baryon-baryon interactions in lattice QCD, the most reliable method so far\nis the potential method, proposed by the Hadrons to Atomic nuclei from Lattice\nQCD (HAL QCD) collaboration, whose formulation, properties and extensions are\nexplained in detail. Using the HAL QCD potential method, potentials between\nnucleons (proton and neutron, denoted by $N$) in the derivative expansion have\nbeen extracted in various cases. The lattice QCD results shown in this chapter\ninclude a Leading Order (LO) central potential in the parity-even $NN(^1S_0)$\nchannel, LO central and tensor potentials in the parity-even\n$NN(^3S_1$-$^3D_1)$ channel, and a Next-to-Leading Order (NLO) spin-orbit\npotential as well as LO potentials in the parity-odd channels. Preliminary\nresults at the almost physical pion and kaon masses, in addition to exploratory\nstudies on three-nucleon potentials, are presented. Interactions between\ngeneric baryons including hyperons, made of one or more strange quarks as well\nas up and down quarks, have also been investigated. Universal properties of\npotentials between baryons become manifest in the flavor SU(3) symmetric limit,\nwhere masses of three quarks, up, down and strange, are all equal. In\nparticular, it is observed that one bound state, traditionally called the\n$H$-dibaryon, appears in the flavor singlet representation of SU(3). A fate of\nthe $H$ dibaryon is also discussed with flavor SU(3) breaking taken into\naccount at the almost physical point. Finally, various kinds of dibaryons,\nbound or resonate states of two baryons, including charmed dibaryons, have been\npredicted by lattice QCD simulations at the almost physical point.",
        "positive": "Nucleon electromagnetic form factors from twisted mass lattice QCD: Results on the electromagnetic form factors of the nucleon using twisted mass\nfermion configurations are presented. These include a gauge field ensemble\nsimulated with two degenerate light quarks yielding a pion mass of around 130\nMeV, as well as two ensembles that include strange and charm quarks in the sea\nyielding pion masses of 210 MeV and 373 MeV. Details of the methods used and\nsystematic errors are discussed, such as noise reduction techniques and the\neffect of excited states contamination."
    },
    {
        "anchor": "Buried treasure in the sand of the QCD vacuum: The short-range structure of the 2+1 flavour QCD vacuum is studied through\nvisualisations of the topological charge density. Of particular interest is a\nnew Gaussian weighted smearing algorithm which is applied to the rough\ntopological charge density to disclose underlying long range structure. The\nresults provide support for the view of the QCD vacuum as a sandwich of\nsign-alternating sheets of charge, with a long-range structure hidden beneath.",
        "positive": "Triviality problem and the high-temperature expansions of the higher\n  susceptibilities for the Ising and the scalar field models on four-, five-\n  and six-dimensional lattices: High-temperature expansions are presently the only viable approach to the\nnumerical calculation of the higher susceptibilities for the spin and the\nscalar-field models on high-dimensional lattices. The critical amplitudes of\nthese quantities enter into a sequence of universal amplitude-ratios which\ndetermine the critical equation of state. We have obtained a substantial\nextension through order 24, of the high-temperature expansions of the free\nenergy (in presence of a magnetic field) for the Ising models with spin s >=\n1/2 and for the lattice scalar field theory with quartic self-interaction, on\nthe simple-cubic and the body-centered-cubic lattices in four, five and six\nspatial dimensions. A numerical analysis of the higher susceptibilities\nobtained from these expansions, yields results consistent with the widely\naccepted ideas, based on the renormalization group and the constructive\napproach to Euclidean quantum field theory, concerning the no-interaction\n(\"triviality\") property of the continuum (scaling) limit of spin-s Ising and\nlattice scalar-field models at and above the upper critical dimensionality."
    },
    {
        "anchor": "A New Lattice Action for Studying Topological Charge: We review our recent proposal for a new lattice action for non-abelian gauge\ntheories which reduces short-range lattice artifacts in the computation of the\ntopological susceptibility. The standard Wilson action is replaced by the\nWilson action of a gauge covariant interpolation of the original fields to a\nfiner lattice. We illustrate the improved behavior of a same-philosophy new\nlattice action in the $O(3)$ $\\sigma$-model in two dimensions.",
        "positive": "Adiabatic Quantum Transport: Quantization and Fluctuations: Quillen's local index theorem is used to study the charge transport\ncoefficients (adiabatic curvature) associated to the ground state of a\nSchr\\\"odinger operator for a charged (spinless) particle on a closed, multiply\nconnected surface. The formula splits the adiabatic curvature into an explicit\nintegral part and a fluctuating part which has a natural interpretation in\nterms of quantum chaos."
    },
    {
        "anchor": "Improving the signal-to-noise-ratio in lattice gauge theories: Renormalization of composite fields is employed to suppress the statistical\nnoise in lattice gauge calculations. We propose a new action which differs from\nthe standard Wilson action by ''irrelevant'' operators, but suppresses the\nfluctuations of the plaquette. We numerically study the Creutz ratios and find\na scaling window. The SU(2) mass gap is estimated. We prove that the\ncontributions of the ''irrelevant'' operators to the screening mass decrease\ntowards the continuum limit. The results obtained from the action with noise\nsuppression are compared with those of the standard Wilson action.",
        "positive": "First Glimpse into the Kaon Gluon Parton Distribution Using Lattice QCD: In this work, we present the first results on the gluon parton distribution\nof the kaon from lattice quantum chromodynamics. We carry out the lattice\ncalculation at pion mass around 310~MeV and two lattice spacings, 0.15 and\n0.12~fm, using $2+1+1$-flavor HISQ ensembles generated by MILC Collaboration.\nThe kaon correlators are calculated using clover fermions and momentum-smearing\nsources with maximum boost momentum around 2~GeV and high statistics (up to\n324,000 measurements). We study the dependence of the resulting reduced\nIoffe-time pseudo-distributions at multiple boost momenta and lattice spacings.\nWe then extract the kaon gluon distribution function in the\n$\\overline{\\text{MS}}$ scheme at $\\mu = 2$~GeV, neglecting the mixing between\nthe gluon and singlet-quark sectors. Our results at the smaller lattice spacing\nare consistent with phenomenological determinations."
    },
    {
        "anchor": "Critical behavior towards the chiral limit at vanishing and\n  non-vanishing chemical potentials: We study the scaling behavior of the (2+1)-flavor QCD crossover region\ntowards the chiral limit with smaller-than-physical light quark mass gauge\nensembles, generated using the HISQ fermion discretization. At zero chemical\npotential, we study the fluctuations of conserved charges and their\ncorrelations with the chiral condensate, towards the chiral limit. We analyse\nthe role of universal and regular contributions to the above quantities. We\nfind a preliminary estimate of the leading curvature coefficient of the chiral\nphase transition line using scaling arguments.",
        "positive": "Finite continuum quasi distributions from lattice QCD: We present a new approach to extracting continuum quasi distributions from\nlattice QCD. Quasi distributions are defined by matrix elements of a\nWilson-line operator extended in a spatial direction, evaluated between nucleon\nstates at finite momentum. We propose smearing this extended operator with the\ngradient flow to render the corresponding matrix elements finite in the\ncontinuum limit. This procedure provides a nonperturbative method to remove the\npower-divergence associated with the Wilson line and the resulting matrix\nelements can be directly matched to light-front distributions via perturbation\ntheory."
    },
    {
        "anchor": "Spectrum of orientifold QCD in the strong coupling and hopping expansion\n  approximation: We use the strong coupling and hopping parameter expansions to calculate the\npion and rho meson masses for lattice Yang-Mills gauge theories with fermions\nin irreducible two-index representations, namely the adjoint, symmetric and\nantisymmetric. The results are found to be consistent with orientifold planar\nequivalence, and leading order 1/N corrections are calculated in the lattice\nphase. An estimate of the critical bare mass, for which the pion is massless,\nis obtained as a function of the bare coupling. A comparison to data from the\ntwo-flavour SU(2) theory with adjoint fermions gives evidence for a bulk phase\ntransition at beta~2, separating a pure lattice phase from a phase smoothly\nconnected to the continuum.",
        "positive": "The Kaon B-parameter with the Wilson Quark Action using Chiral Ward\n  Identities: We present a detailed description of the method and results of our\ncalculation of the kaon B parameter using the Wilson quark action in quenched\nQCD at $\\beta=5.9-6.5$. The mixing problem of the $\\Delta s=2$ four-quark\noperators is solved non-perturbatively with full use of chiral Ward identities.\nWe find $B_K(NDR, 2 GeV)=0.562(64)$ in the continuum limit, which agrees with\nthe value obtained with the Kogut-Susskind quark action."
    },
    {
        "anchor": "Non-renormalization theorem and cyclic Leibniz rule in lattice\n  supersymmetry: We propose a lattice model of supersymmetric complex quantum mechanics which\nrealizes the non-renormalization theorem on a lattice. In our lattice model,\nthe Leibniz rule in the continuum, which cannot hold on a lattice due to a\nno-go theorem, is replaced by the cyclic Leibniz rule (CLR) for difference\noperators. It is shown that CLR allows two of four supercharges of the\ncontinuum theory to preserve while a naive lattice model can realize one\nsupercharge at the most. A striking feature of our lattice model is that there\nare no quantum corrections to potential terms in any finite order of\nperturbation theory. This is one of characteristic properties of supersymmetric\ntheories in the continuum. It turns out that CLR plays a crucial role in the\nproof of the non-renormalization theorem. This result suggests that CLR grasps\nan essence of supersymmetry on a lattice.",
        "positive": "Renormalization group and triviality in noncompact lattice QED with\n  light fermions: In the framework of noncompact lattice QED with light fermions, we derive the\nfunctional dependence of the average energy per plaquette on the bare\nparameters using block-spin Renormalization Group arguments and assuming that\nthe renormalized coupling vanishes. Our numerical results for this quantity in\n$8^4$ and $10^4$ lattices show evidence for triviality in the weak coupling\nphase and point to a non vanishing value for the renormalized coupling constant\nin the strong coupling phase."
    },
    {
        "anchor": "Gauge model at finite temperature with massive quarks and at finite\n  density on anisotropic lattice: Critical properties of QCD and the chiral condensate at finite density are\nanalytically studied on an anisotropic lattice in the approximation SU(N)\n\\simeq Z(N). Asymptotic behavior of the partition function and its continuum\nlimit are discussed.",
        "positive": "Casimir Scaling in SU(2) Lattice Gauge Theory: By employing the multilevel algorithm in numerical Monte Carlo simulations,\nwe evaluate the static potential in four dimensional SU(2) lattice gauge theory\nwith no dynamical fermions, for static sources in the j=1/2,1,3/2\nrepresentations. We find data supporting the Casimir scaling hypothesis. With\nthe same technique we show that the ratio of the logarithm of Wilson loops in\nthe j=2 and j=1/2 representations, as a function of the area of the loops, also\nsatisfies Casimir scaling."
    },
    {
        "anchor": "FK/Fpi in full QCD: We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based\non a series of lattice calculations with three different couplings, large\nvolumes and a simulated pion mass reaching down to about 190 MeV. We obtain\nFK/Fpi = 1.192 +- 0.007(stat) +- 0.006(sys) with all the sources of systematic\nuncertainty under control.",
        "positive": "Pseudoscalar-pole contributions to the muon $g-2$ at the physical point: Pseudoscalar-pole diagrams are an important component of estimates of the\nhadronic light-by-light (HLbL) contribution to the muon $g-2$. We report on our\ncomputation of the transition form factors $\\mathcal{F}_{P \\rightarrow \\gamma^*\n\\gamma^*}$ for the neutral pseudoscalar mesons $P=\\pi^0$ and $\\eta$. The\ncalculation is performed using twisted-mass lattice QCD with physical quark\nmasses. On the lattice, we have access to a broad range of (space-like) photon\nfour-momenta and therefore produce form factor data complementary to the\nexperimentally accessible single-virtual direction, which directly leads to an\nestimate of the pion- and $\\eta$-pole components of the muon $g-2$. For the\npion, our result for the $g-2$ contribution in the continuum is comparable with\nprevious lattice and data-driven determinations, with combined relative\nuncertainties below $10\\%$. For the $\\eta$ meson, we report on a preliminary\ndetermination from a single lattice spacing."
    },
    {
        "anchor": "QED in 2+1 Dimensions with Fermi and Gap Anisotropies: QED in 2+1 dimensions has long been studied as a model field theory which\nexhibits both asymptotic freedom and non-trivial IR behaviour. There is also a\ntrend towards viewing it as a candidate low energy effective theory for the\npseudogap phase of high temperature superconductors. One feature of these\ntheories is their lack of isotropy in the x and y directions (a common feature\nof Dirac theories in condensed matter systems). A model motivated by this work\nis outlined, and tentative evidence presented for chiral symmetry restoration\nas the relative anisotropy is increased.",
        "positive": "The $\\mathrm{SU}(3)$ twisted gradient flow strong coupling without\n  topology freezing: We investigate the role of topology in the lattice determination of the\nrenormalized strong coupling via the gradient flow. This is done adopting the\nParallel Tempering on Boundary Conditions to deal with the infamous topological\nfreezing problem that affects standard local updating algorithms. We show that,\neven in the presence of severe topological freezing, both algorithms yield the\nsame strong coupling once projected onto a fixed topological sector. Moreover,\nwe show that using a non-projected definition of the coupling leads to the same\nstep-scaling sequence. This means that projecting the coupling onto a fixed\ntopological sector does not affect the determination of the\ndynamically-generated scale of the theory $\\Lambda$."
    },
    {
        "anchor": "Some aspects of simulation algorithms for dynamical fermions: Three topics concerning fermion simulation algorithms are discussed: 1.) A\nperformance comparison of the multiboson technique to simulate dynamical\nfermions and the Kramers equation algorithm, 2.) the question of reversibility\nin the Hybrid Monte Carlo algorithm and 3.) the implementation of Symanzik's\nimprovement program for dynamical Wilson fermions.",
        "positive": "String breaking in zero-temperature lattice QCD: The crossing from a static quark-antiquark system to a system of two\nstatic-light mesons when the separation of the static quarks is increased is\ncalculated in zero-temperature lattice QCD. The mixing of these two states is\nextracted from the lattice operators. We also discuss the breaking of an\nexcited string of a hybrid meson."
    },
    {
        "anchor": "Equation of State and Heavy-Quark Free Energy at Finite Temperature and\n  Density in Two Flavor Lattice QCD with Wilson Quark Action: We study the equation of state at finite temperature and density in\ntwo-flavor QCD with the RG-improved gluon action and the clover-improved Wilson\nquark action on a $ 16^3 \\times 4$ lattice. Along the lines of constant physics\nat $m_{\\rm PS}/m_{\\rm V} = 0.65$ and 0.80, we compute the second and forth\nderivatives of the grand canonical partition function with respect to the quark\nchemical potential $\\mu_q = (\\mu_u+\\mu_d)/2$ and the isospin chemical potential\n$\\mu_I = (\\mu_u-\\mu_d)/2$ at vanishing chemical potentials, and study the\nbehaviors of thermodynamic quantities at finite $\\mu_q$ using these derivatives\nfor the case $\\mu_I=0$. In particular, we study density fluctuations at\nnone-zero temperature and density by calculating the quark number and isospin\nsusceptibilities and their derivatives with respect to $\\mu_q$. To suppress\nstatistical fluctuations, we also examine new techniques applicable at low\ndensities. We find a large enhancement in the fluctuation of quark number when\nthe density increased near the pseudo-critical temperature, suggesting a\ncritical point at finite $\\mu_q$ terminating the first order transition line\nbetween hadronic and quark gluon plasma phases. This result agrees with the\nprevious results using staggered-type quark actions qualitatively. Furthermore,\nwe study heavy-quark free energies and Debye screening masses at finite density\nby measuring the first and second derivatives of these quantities for various\ncolor channels of heavy quark-quark and quark-anti-quark pairs. The results\nsuggest that, to the leading order of $\\mu_q$, the interaction between two\nquarks becomes stronger at finite densities, while that between quark and\nanti-quark becomes weaker.",
        "positive": "Electromagnetic Effects on Strongly Interacting QCD-Matter: In order to study the temperature dependence of the quark-hadron phase\nstructure and the QCD equation of state in vanishing and finite magnetic field,\nthe SU(3) Polyakov linear-sigma model is utilized. In mean field approximation,\nthe dependence of various magnetic properties such as magnetization, magnetic\nsusceptibility and magnetic catalysis is analyzed in finite magnetic field.\nFurthermore, the influences of finite magnetic field on the temperature\ndependence of some transport properties (viscosity and conductivity) from\nGreen-Kubo correlation are characterized."
    },
    {
        "anchor": "Eigenvalue repulsion in an effective theory of SU(2) Wilson lines in\n  three dimensions: We perform simulations of an effective theory of SU(2) Wilson lines in three\ndimensions. We include a non-perturbative \"fuzzy-bag\" contribution which is\nadded to the one-loop perturbative potential for the Wilson line. We confirm\nthat, at moderately weak coupling, this leads to eigenvalue repulsion in a\nfinite region above the deconfining phase transition which shrinks in the\nextreme weak-coupling limit. A non-trivial Z(N) symmetric vacuum arises in the\nconfined phase.",
        "positive": "Properties of the $\u03b7$ and $\u03b7^{\\prime}$ mesons: Masses, decay\n  constants and gluonic matrix elements: We present results for the $\\eta$ and $\\eta^\\prime$ masses and their four\nindependent decay constants at the physical point as well as their anomalous\ngluonic matrix elements $a_{\\eta^{(\\prime)}}$. The chiral and continuum limit\nextrapolation is performed on twenty-one $N_f = 2+1$ Coordinated Lattice\nSimulations (CLS) ensembles with non-perturbatively improved Wilson fermions at\nfour different lattice spacings and along two trajectories in the quark mass\nplane, including one ensemble very close to physical quark masses. For the\nfirst time the decay constants are determined directly from the axialvector\nmatrix elements without model assumptions. This allows us to study their QCD\nscale dependence and to determine all low-energy constants contributing at\nnext-to-leading order in large-$N_c$ ChPT at a well defined QCD renormalization\nscale. We also discuss higher excited states in the $1400\\,\\mathrm{MeV}$\nregion."
    },
    {
        "anchor": "Hybrid static potentials in SU(2) lattice gauge theory at short\n  quark-antiquark separations: We compute hybrid static potentials in SU(2) lattice gauge theory using a\nmultilevel algorithm and three different small lattice spacings. The resulting\nstatic potentials, which are valid for quark-antiquark separations as small as\n0.05 fm, are important e.g. when computing masses of heavy hybrid mesons in the\nBorn-Oppenheimer approximation. We also discuss and exclude possible systematic\nerrors from topological freezing, the finite lattice volume and glueball\ndecays.",
        "positive": "The Gluon Propagator without lattice Gribov copies on a finer lattice: We extend our study of the gluon propagator in quenched lattice QCD using the\nLaplacian gauge to a finer lattice. We verify the existence of a pole mass as\nwe take the continuum limit and deduce a value of $\\sim 600^{+150}_{-30}$ MeV\nfor this pole mass. We find a finite value of $(454(5){\\rm MeV})^{-2}$ for the\nrenormalized zero-momentum propagator, in agreement with results on coarser\nlattices."
    },
    {
        "anchor": "New Physics Searches from Nucleon Matrix Elements in Lattice QCD: In this paper we review recent progress in hadron structure using lattice QCD\nsimulations, with main focus in the evaluation of nucleon matrix elements. We\nhighlight developments that may guide new Physics searches, such as the scalar\nand tensor charges, as well as, the neutron electric dipole moment.",
        "positive": "Parallel tempering algorithm for integration over Lefschetz thimbles: The algorithm based on integration over Lefschetz thimbles is a promising\nmethod to resolve the sign problem for complex actions. However, this algorithm\noften meets a difficulty in actual Monte Carlo calculations because the\nconfiguration space is not easily explored due to the infinitely high potential\nbarriers between different thimbles. In this paper, we propose to use the flow\ntime of the antiholomorphic gradient flow as an auxiliary variable for the\nhighly multimodal distribution. To illustrate this, we implement the parallel\ntempering method by taking the flow time as a tempering parameter. In this\nalgorithm, we can take the maximum flow time to be sufficiently large such that\nthe sign problem disappears there, and two separate modes are connected through\nconfigurations at small flow times. To exemplify that this algorithm does work,\nwe investigate the (0+1)-dimensional massive Thirring model at finite density\nand show that our algorithm correctly reproduces the analytic results for large\nflow times such as T=2."
    },
    {
        "anchor": "Hadron-hadron total cross sections and soft high-energy scattering on\n  the lattice: The nonperturbative approach to soft high-energy hadron-hadron scattering,\nbased on the analytic continuation of Euclidean Wilson-loop correlation\nfunctions, makes possible the investigation of the problem of the asymptotic\nenergy dependence of hadron-hadron total cross sections by means of lattice\ncalculations. In this contribution we compare the lattice numerical results to\nanalytic results obtained with various nonperturbative techniques. We also\ndiscuss the possibility to obtain indications of the rise of hadron-hadron\ntotal cross sections with energy directly from the lattice data.",
        "positive": "A numerical test of the continuum index theorem on the lattice: The overlap formalism of chiral fermions provides a tool to measure the\nindex, Q, of the chiral Dirac operator in a fixed gauge field background on the\nlattice. This enables a numerical measurement of the probability distribution,\np(Q), in Yang-Mills theories. We have obtained an estimate for p(Q) in pure\nSU(2) gauge theory by measuring Q on 140 independent gauge field configurations\ngenerated on a 12^4 lattice using the standard single plaquette Wilson action\nat a coupling of beta=2.4. This distribution is in good agreement with a recent\nmeasurement [8] of the distribution of the topological charge on the same\nlattice using the same coupling and the same lattice gauge action. In\nparticular we find <Q^2>=3.3(4) to be compared with <Q^2> = 3.9(5) found in\n[8]. The good agreement between the two distributions is an indication that the\ncontinuum index theorem can be carried over in a probabilistic sense on to the\nlattice."
    },
    {
        "anchor": "The String Tension in Gauge Theories: A review article on string tension concept and their relevance as\nnon-perturbative quantity on the study of quark confinement in lattice gauge\ntheories. A detailed description of a variety of methods to measure the string\ntension on the lattice and an indication of the most promising developments is\nproposed.",
        "positive": "Finite-volume effects due to spatially non-local operators: Spatially non-local matrix elements are useful lattice-QCD observables in a\nvariety of contexts, for example in determining hadron structure. To quote\ncredible estimates of the systematic uncertainties in these calculations, one\nmust understand, among other things, the size of the finite-volume effects when\nsuch matrix elements are extracted from numerical lattice calculations. In this\nwork, we estimate finite-volume effects for matrix elements of non-local\noperators, composed of two currents displaced in a spatial direction by a\ndistance $\\xi$. We find that the finite-volume corrections depend on the\ndetails of the matrix element. If the external state is the lightest degree of\nfreedom in the theory, e.g.~the pion in QCD, then the volume corrections scale\nas $ e^{-m_\\pi (L- \\xi)} $, where $m_\\pi$ is the mass of the light state. For\nheavier external states the usual $e^{- m_\\pi L}$ form is recovered, but with a\npolynomial prefactor of the form $L^m/|L - \\xi|^n$ that can lead to enhanced\nvolume effects. These observations are potentially relevant to a wide variety\nof observables being studied using lattice QCD, including parton distribution\nfunctions, double-beta-decay and Compton-scattering matrix elements, and\nlong-range weak matrix elements."
    },
    {
        "anchor": "Understanding Hadron Structure Using Lattice QCD: An elementary introduction is presented to the study of hadron structure\nusing lattice QCD. Following a brief review of relevant aspects of path\nintegrals, the discrete lattice path integral is presented for gluon and quark\nfields and used to calculate physical observables. Essential aspects of\ninstanton physics are reviewed, and it is shown how the instanton content is\nextracted from lattice gluon configurations. Finally, both comparison of\nresults including all gluons with those including only instantons and the study\nof quark zero modes associated with instantons and their contributions to\nhadronic observables are used to show the dominant role of gluons in hadron\nstructure.",
        "positive": "Charmonium and bottomonium spectral functions in the vector channel: In this paper we report our results on quarkonium spectral functions in the\nvector channel obtained from quenched lattice QCD simulations at $T\\in[0.75,\n2.25]~T_c$. The calculations have been performed on very large and fine\nisotropic lattices where both charm and bottom quarks can be treated\nrelativistically. The spectral functions are reconstructed using the Maximum\nEntropy Method. We study the dissociation of quarkonium states from the\ntemperature dependence of the spectral functions and estimate heavy quark\ndiffusion coefficients using the low-frequency behavior of the vector spectral\nfunctions."
    },
    {
        "anchor": "Hadron Structure in Lattice QCD: Exploring the Gluon Wave Functional: The use of lattice QCD to understand hadron structure is described, with\nparticular emphasis on exploring the role of glue.",
        "positive": "2021 Update on $\\varepsilon_K$ with lattice QCD inputs: We present recent updates for $\\varepsilon_K$ determined directly from the\nstandard model (SM) with lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $f_K$, and $m_c$. We find that\nthe standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs\ndescribes only 66\\% of the experimental value of $|\\varepsilon_K|$ and does not\nexplain its remaining 34\\%, which leads to a strong tension in\n$|\\varepsilon_K|$ at the $4.5\\sigma \\sim 3.7\\sigma$ level between the SM theory\nand experiment. We also find that this tension disappears when we use the\ninclusive value of $|V_{cb}|$ obtained using the heavy quark expansion based on\nthe QCD sum rule approach."
    },
    {
        "anchor": "Covariance fitting of highly correlated data in lattice QCD: We address a frequently asked question on the covariance fitting of the\nhighly correlated data such as our $B_K$ data based on the SU(2) staggered\nchiral perturbation theory. Basically, the essence of the problem is that we do\nnot have an accurate fitting function enough to fit extremely precise data.\nWhen eigenvalues of the covariance matrix are small, even a tiny error of\nfitting function yields large chi-square and spoils the fitting procedure. We\nhave applied a number of prescriptions available in the market such as the\ncut-off method, modified covariance matrix method, and Bayesian method. We also\npropose a brand new method, the eigenmode shift method which allows a full\ncovariance fitting without modifying the covariance matrix at all. In our case,\nthe eigenmode shift (ES) method and Bayesian method turn out to be the best\nprescription to the problem. We also provide a pedagogical example of data\nanalysis in which the diagonal approximation and the cut-off method fail in\nfitting manifestly, but the ES method and the Bayesian approach work well.",
        "positive": "Stealth dark matter confinement transition and gravitational waves: We use non-perturbative lattice calculations to investigate the\nfinite-temperature confinement transition of stealth dark matter, focusing on\nthe regime in which this early-universe transition is first order and would\ngenerate a stochastic background of gravitational waves. Stealth dark matter\nextends the standard model with a new strongly coupled SU(4) gauge sector with\nfour massive fermions in the fundamental representation, producing a stable\nspin-0 'dark baryon' as a viable composite dark matter candidate. Future\nsearches for stochastic gravitational waves will provide a new way to discover\nor constrain stealth dark matter, in addition to previously investigated\ndirect-detection and collider experiments. As a first step to enabling this\nphenomenology, we determine how heavy the dark fermions need to be in order to\nproduce a first-order stealth dark matter confinement transition."
    },
    {
        "anchor": "On isospin breaking in $\u03c4$ decays for $(g-2)_\u03bc$ from Lattice QCD: Hadronic spectral functions of $\\tau$ decays have been used in the past to\nprovide an alternative determination of the LO Hadronic Vacuum Polarization\nrelevant for the (g-2) of the muon. Following recent developments and results\nin Lattice QCD+QED calculations, we explore the possibility of studying the\nisospin breaking corrections of $\\tau$ spectral functions for this prediction.\nWe present preliminary results at physical pion mass based on Domain Wall\nFermion ensembles generated by the RBC/UKQCD collaboration.",
        "positive": "Orientifold Planar Equivalence: The Quenched Meson Spectrum: A numerical study of Orientifold Planar Equivalence is performed in SU(N)\nYang-Mills theories for N=2,3,4,6. Quenched meson masses are extracted in the\nantisymmetric, symmetric and adjoint representations for the pseudoscalar and\nvector channels. An extrapolation of the vector mass as a function of the\npseudoscalar mass to the large-N limit shows that the numerical results agree\nwithin errors for the three theories, as predicted by Orientifold Planar\nEquivalence. As a byproduct of the extrapolation, the size of the corrections\nup to O(1/N^3) are evaluated. A crucial prerequisite for the extrapolation is\nthe determination of an analytical relationship between the corrections in the\nsymmetric and in the antisymmetric representations, order by order in a 1/N\nexpansion."
    },
    {
        "anchor": "Study of chiral and deconfinement transition in lattice QCD with\n  improved staggered actions: We present results on the chiral and deconfinement properties of the QCD\ntransition at finite temperature. We performed calculations using asqtad and\nHISQ/tree actions using lattices with temporal extent N_tau=6, 8 and 12\nallowing to control the approach to the continuum limit. We analyze the chiral\ntransition in terms of universal O(N) scaling functions. From peaks in the\nscaling functions we perform a simultaneous continuum extrapolation for\nHISQ/tree and asqtad to derive the critical temperature, T_c= 157 +/- 6 MeV.",
        "positive": "Hadron matrix elements for nucleon decay with the Wilson quark action: We report preliminary results of our study of matrix elements of baryon\nnumber violating operators which appear in the low-energy effective Lagrangian\nof (SUSY-)Grand Unified Theories. The calculation is performed on a\n$32^{3}\\times80$ lattice at $\\beta=6.1$ using Wilson fermions in the quenched\napproximation. Our calculation is independent of details of (SUSY-)GUT models\nand covers all interesting decay modes."
    },
    {
        "anchor": "Thermal interquark potentials for bottomonium using NRQCD from the HAL\n  QCD method: We report our preliminary progress in the calculation of the interquark\npotential of bottomonium at non-zero temperature using the HAL QCD method. We\nuse NRQCD correlation functions of non-local mesonic S-wave states to obtain\nthe central potential as a function of temperature. These results have been\nobtained using our anisotropic 2+1 flavour \"Generation 2\" FASTSUM ensembles.",
        "positive": "K\u00e4ll\u00e9n-Lehmann Spectral Representation of the Scalar SU(2) Glueball: The estimation of the K\\\"all\\'en-Lehmann spectral density from gauge\ninvariant lattice QCD two point correlation functions is proposed, and explored\nvia an appropriate inversion method. As proof of concept the SU(2) glueball\nspectrum for the quantum numbers $J^{PC} = 0^{++}$ is investigated for various\nvalues of the lattice spacing. The spectral density and the glueball spectrum\nare estimated using the published data of arXiv:1910.07756. Our estimates for\nthe ground state mass are in good agreement with the traditional approach\npublished therein, which is based on the large time exponential behaviour of\nthe correlation functions. Furthermore, the spectral density also contains\nhints of excites states in the spectrum."
    },
    {
        "anchor": "Wilson twisted mass fermions in the epsilon regime: In this proceeding contribution we report on the ongoing effort to understand\nand simulate Wilson twisted mass fermions in the so called epsilon regime.",
        "positive": "Renormalization of HQET $\u0394B=2$ operators: O($a$) improvement and\n  $1/m$ matching with QCD: We determine a basis of dimension-7 operators which arise at O($a$) in the\nSymanzik expansion of the $\\Delta B=2$ operators with static heavy quarks. We\nconsider both Wilson-like and Ginsparg-Wilson light quarks. Exact chiral\nsymmetry reduces the number of these O($a$) counterterms by a factor of two.\nOnly a subset of these operators has previously appeared in the literature. We\nthen extend the analysis to the O($1/m$) operators contributing beyond the\nstatic approximation."
    },
    {
        "anchor": "Lattice regularisation and entanglement structure of the Gross-Neveu\n  model: We construct a Hamiltonian lattice regularisation of the $N$-flavour\nGross-Neveu model that manifestly respects the full $\\mathsf{O}(2N)$ symmetry,\npreventing the appearance of any unwanted marginal perturbations to the quantum\nfield theory. In the context of this lattice model, the dynamical mass\ngeneration is intimately related to the Coleman-Mermin-Wagner and\nLieb-Schultz-Mattis theorem. In particular, the model can be interpreted as\nlying at the first order phase transition line between a trivial and\nsymmetry-protected topological (SPT) phase, which explains the degeneracy of\nthe elementary kink excitations. We show that our Hamiltonian model can be\nsolved analytically in the large $N$ limit, producing the correct expression\nfor the mass gap. Furthermore, we perform extensive numerical matrix product\nstate simulations for $N=2$, thereby recovering the emergent Lorentz symmetry\nand the proper non-perturbative mass gap scaling in the continuum limit.\nFinally, our simulations also reveal how the continuum limit manifests itself\nin the entanglement spectrum. As expected from conformal field theory we find\ntwo conformal towers, one tower spanned by the linear representations of\n$\\mathsf{O}(4)$, corresponding to the trivial phase, and the other by the\nprojective (i.e. spinor) representations, corresponding to the SPT phase.",
        "positive": "Study of CP(N-1) \u03b8-Vacua by Cluster-Simulation of SU(N) Quantum\n  Spin Ladders: D-theory provides an alternative lattice regularization of the (1+1)-d\nCP(N-1) quantum field theory. In this formulation the continuous classical\nCP(N-1) fields emerge from the dimensional reduction of discrete SU(N) quantum\nspins. In analogy to Haldane's conjecture, ladders consisting of an even number\nof transversely coupled spin chains lead to a CP(N-1) model with vacuum angle\n\\theta = 0, while an odd number of chains yields \\theta = \\pi. In contrast to\nWilson's formulation of lattice field theory, in D-theory no sign problem\narises at \\theta = \\pi, and an efficient cluster algorithm is used to\ninvestigate the \\theta-vacuum effects. At \\theta = \\pi there is a first order\nphase transition with spontaneous breaking of charge conjugation symmetry for\nCP(N-1) models with N>2."
    },
    {
        "anchor": "Behavior of Hadrons at Finite Density -- Lattice Study of Color SU(2)\n  QCD: Using two-color lattice QCD with Wilson fermions, we report a study of the\nfinite baryon number density system with two-flavors. First we investigate the\nPolyakov line and thermodynamical uantities in the $(\\kappa,\\mu)$ plane, where\n$\\kappa$ and $\\mu$ are the hopping parameter and chemical potential in the\nfermion action, respectively. Then we calculate propagators of meson\n($\\bar{q}\\Gamma q$) and baryon ($q\\Gamma q$) states. We find that the vector\nmeson propagators are strongly modified in large $\\mu$ regions, indicating the\nreduction of the mass. This anomalous behavior of the vector meson is observed\nfor the first time in lattice QCD.",
        "positive": "Bound states in the 3d Ising model and implications for QCD at finite\n  temperature and density: We study the spectrum of bound states of the three dimensional Ising model in\nthe (h,beta) plane near the critical point. We show the existence of an\nunbinding line, defined as the boundary of the region where bound states exist.\nNumerical evidence suggests that this line coincides with the beta=beta_c axis.\nWhen the 3D Ising model is considered as an effective description of hot QCD at\nfinite density, we conjecture the correspondence between the unbinding line and\nthe line that separates the quark-gluon plasma phase from the superconducting\nphase. The bound states of the Ising model are conjectured to correspond to the\ndiquarks of the latter phase of QCD."
    },
    {
        "anchor": "The monopole content of topological clusters : have KvB calorons been\n  found?: Using smearing of equilibrium lattice fields generated at finite temperature\nin the confined phase of SU(2) lattice gauge theory, we have investigated the\nemerging topological objects (clusters of topological charge). Analysing their\nmonopole content according to the Polyakov gauge and the maximally Abelian\ngauge, we characterize part of them to correspond to nonstatic calorons or\nstatic dyons in the context of Kraan-van Baal caloron solutions with\nnon-trivial holonomy. The behaviour of the Polyakov loop inside these clusters\nand the (model-dependent) topological charges of these objects support this\ninterpretation.",
        "positive": "Vortices in SU(2) lattice gauge theory: We investigate some properties of thick vortices and thick monopoles in the\nSU(2) lattice gauge theory by inserting operators which create these\nexcitations. Some quantities associated with the dynamical behaviour of thick\nvortices and thick monopoles are studied. We measure the derivative of the free\nenergy of the vortex with respect to the coupling and we find that it falls\nexponentially with the cross sectional area of the vortex size. We also study\nthe monopole-monopole potential energy for thick and thin monopoles. Our\nresults suggest that vortices and monopoles of increasing thickness will play\nan important role in the large $\\beta$ limit."
    },
    {
        "anchor": "Electromagnetic splittings of hadrons from improved staggered quarks in\n  full QCD: We present our initial study of the electromagnetic splittings of charged and\nneutral mesons, and the violation of Dashen's theorem. Hadron masses are\ncalculated on MILC N_f=2+1 QCD ensembles at lattice spacing \\approx 0.15fm,\ntogether with quenched non-compact U(1) configurations. The O(a^2) tadpole\nimproved staggered quark (asqtad) action is used both for the sea quarks and\nfor six different valence quark masses. Chiral extrapolations are performed\nusing partially quenched chiral perturbation theory incorporating\nelectromagnetic corrections.",
        "positive": "Chiral phase transition in a random matrix model with three flavors: The chiral phase transition in the conventional random matrix model is the\nsecond order in the chiral limit, irrespective of the number of flavors N_f,\nbecause it lacks the U_A(1)-breaking determinant interaction term. Furthermore,\nit predicts an unphysical value of zero for the topological susceptibility at\nfinite temperatures. We propose a new chiral random matrix model which resolves\nthese difficulties by incorporating the determinant interaction term within the\ninstanton gas picture. The model produces a second-order transition for N_f=2\nand a first-order transition for N_f=3, and recovers a physical temperature\ndependence of the topological susceptibility."
    },
    {
        "anchor": "Dynamical overlap fermion simulations with a preconditioned Hybrid Monte\n  Carlo force: We present simulation results for the 2-flavour Schwinger model with\ndynamical Ginsparg-Wilson fermions. Our Dirac operator is constructed by\ninserting an approximately chiral hypercube operator into the overlap formula,\nwhich yields the overlap hypercube operator. Due to the similarity with the\nhypercubic kernel, a low polynomial of this kernel can be used as a numerically\ncheap way to evaluate the fermionic part of the Hybrid Monte Carlo force. We\nverify algorithmic requirements like area conservation and reversibility, and\nwe discuss the viability of this approach in view of the acceptance rate. Next\nwe confirm a high level of locality for this formulation. Finally we evaluate\nthe chiral condensate at light fermion masses, based on the density of low\nlying Dirac eigenvalues in different topological sectors. The results represent\none of the first measurements with dynamical overlap fermions, and they agree\nvery well with analytic predictions at weak coupling.",
        "positive": "Anatomy of the lattice magnetic monopoles: We study the Abelian and non-Abelian action densitynear the monopole in the\nmaximal Abelian gauge of SU(2) lattice gauge theory. We find that the\nnon-Abelian action density near the monopoles belonging to the percolating\ncluster decreases when we approach the monopole center. Our estimate of the\nmonopole radius is R_mon ~ 0.04 fm."
    },
    {
        "anchor": "The twelve-flavor $\\boldsymbol\u03b2$-function and dilaton tests of the\n  sextet scalar: We discuss near-conformal gauge theories beyond the standard model (BSM)\nwhere interesting results on the twelve-flavor $\\beta$-function of massless\nfermions in the fundamental representation of the SU(3) color gauge group and\ndilaton tests of the light scalar with two massless fermions in the two-index\nsymmetric tensor (sextet) representation can be viewed as parts of the same BSM\nparadigm under investigation. We report results from high precision analysis of\nthe twelve-flavor $\\beta$-function \\cite{Fodor:2016zil} refuting its published\nIRFP \\cite{Cheng:2014jba,Hasenfratz:2016dou}. We present our objections to\nrecent claims \\cite{Hasenfratz:2017mdh,Hasenfratz:2017qyr} for non-universal\nbehavior of staggered fermions used in our analysis. We also report our first\nanalysis of dilaton tests of the light $0^{++}$ scalar in the sextet model and\ncomment on related post-conference developments. The dilaton test is the main\nthrust of this conference contribution including presentation #405 on the\n$n_f=12$ $\\beta$-function and presentation #260 on dilaton tests of the sextet\nmodel. They are both selected from the near-conformal BSM paradigm.",
        "positive": "Axial coupling constant of the nucleon for two flavours of dynamical\n  quarks in finite and infinite volume: We present data for the axial coupling constant g_A of the nucleon obtained\nin lattice QCD with two degenerate flavours of dynamical non-perturbatively\nimproved Wilson quarks. The renormalisation is also performed\nnon-perturbatively. For the analysis we give a chiral extrapolation formula for\ng_A based on the small scale expansion scheme of chiral effective field theory\nfor two degenerate quark flavours. Applying this formalism in a finite volume\nwe derive a formula that allows us to extrapolate our data simultaneously to\nthe infinite volume and to the chiral limit. Using the additional lattice data\nin finite volume we are able to determine the axial coupling of the nucleon in\nthe chiral limit without imposing the known value at the physical point."
    },
    {
        "anchor": "Kaon Condensation with Lattice QCD: Kaon condensation may play an important role in the structure of hadronic\nmatter at densities greater than that of nuclear matter, as exist in the\ninterior of neutron stars. We present the results of the first lattice QCD\ninvestigation of kaon condensation obtained by studying systems containing up\nto twelve negatively charged kaons. Surprisingly, the properties of the\ncondensate that we calculate are remarkably well reproduced by leading order\nchiral perturbation theory. In our analysis, we also determine the three-kaon\ninteraction from the multi-kaon systems and update our results for pion\ncondensates.",
        "positive": "Im$A_0$, Im$A_2$, and $\u03b5^\\prime$ from quenched lattice QCD: We present results for the imaginary parts of the I=0 and 2 $K\\to\\pi\\pi$\ndecay amplitudes, Im$A_{0,2}$, and the ratio of CP violation parameters,\n$\\epsilon^\\prime/\\epsilon$. Our calculation is done in the quenched\napproximation at $a^{-1}\\approx 2$ GeV, lattice size $16^3\\times 32$, using\ndomain wall fermions with $L_s=16$. We study the three flavor case (charm is\nnot an active flavor) and find $\\epsilon^\\prime/\\epsilon$ is small and slightly\nnegative."
    },
    {
        "anchor": "Accelerating lattice quantum field theory calculations via interpolator\n  optimization using NISQ-era quantum computing: The only known way to study quantum field theories in non-perturbative\nregimes is using numerical calculations regulated on discrete space-time\nlattices. Such computations, however, are often faced with exponential\nsignal-to-noise challenges that render key physics studies untenable even with\nnext generation classical computing. Here, a method is presented by which the\noutput of small-scale quantum computations on Noisy Intermediate-Scale Quantum\nera hardware can be used to accelerate larger-scale classical field theory\ncalculations through the construction of optimized interpolating operators. The\nmethod is implemented and studied in the context of the 1+1-dimensional\nSchwinger model, a simple field theory which shares key features with the\nstandard model of nuclear and particle physics.",
        "positive": "Rare decay B -> K ll form factors from lattice QCD: We calculate, for the first time using unquenched lattice QCD, form factors\nfor the rare decay B -> Kll in and beyond the Standard Model. Our lattice QCD\ncalculation utilizes a nonrelativistic QCD formulation for the b valence\nquarks, the highly improved staggered quark formulation for the light valence\nquarks, and employs the MILC 2+1 asqtad ensembles. The form factor results,\nbased on the z expansion, are valid over the full kinematic range of q^2. We\nconstruct the ratios f0/f+ and fT/f+, which are useful in constraining new\nphysics and verifying effective theory form factor symmetry relations. We also\ndiscuss the calculation of Standard Model observables."
    },
    {
        "anchor": "Dependence of Dirac eigenmodes on boundary conditions for SU(2) lattice\n  gauge theory: We analyze zero modes of the Dirac operator for SU(2) lattice gauge theory.\nWe find that the zero modes are strongly localized in all 4 directions. The\nposition of these lumps depends on the boundary conditions we use for the Dirac\noperator. We compare periodic boundary conditions and anti-periodic boundary\nconditions and find that the position of the zero modes jumps for about one\nthird of the configurations.",
        "positive": "Static quark anti-quark interactions at non-zero temperature from\n  lattice QCD: We present results on the in-medium interactions of static quark anti-quark\npairs using realistic 2+1 HISQ flavor lattice QCD. Focus is put on the\nextraction of spectral information from Wilson line correlators in Coulomb\ngauge using four complementary methods. Our results indicate that on HISQ\nlattices, the position of the dominant spectral peak associated with the\nreal-part of the interquark potential remains unaffected by temperature. This\nis in contrast to prior work in quenched QCD and we present follow up\ncomparisons to newly generated quenched ensembles."
    },
    {
        "anchor": "Quark mass dependence of baryon properties: I discuss the quark mass dependence of various baryon properties derived from\nchiral perturbation theory. Such representations can eventually be used as\nchiral extrapolation functions when lattice data at sufficiently small quark\nmasses become available. The quark mass dependence is encoded in loop and\ncontact term contributions, the latter given in terms of low-energy constants.\nI stress the importance of utilizing phenomenological input to constrain a\ncertain class of low-energy constants and discuss the ensuing theoretical\nuncertainty for various baryon observables, like the nucleon and the baryon\noctet masses, the nucleon isovector anomalous magnetic moment and the\naxial-vector coupling of the nucleon. I stress the role of resonance decoupling\nand present first results for the delta mass based on an effective field theory\nin which the nucleon-delta mass splitting is counted as a small parameter. I\nalso discuss briefly the pion mass dependence of the nuclear force as derived\nfrom chiral nuclear effective field theory.",
        "positive": "The beta function and equation of state for QCD with two flavors of\n  quarks: We measure the pressure and energy density of two flavor QCD in a wide range\nof quark masses and temperatures. The pressure is obtained from an integral\nover the average plaquette or psi-bar-psi. We measure the QCD beta function,\nincluding the anomalous dimension of the quark mass, in new Monte Carlo\nsimulations and from results in the literature. We use it to find the\ninteraction measure, E-3p, yielding non-perturbative values for both the energy\ndensity E and the pressure p. uuencoded compressed PostScript file Revised\nversion should work on more PostScript printers."
    },
    {
        "anchor": "Charm quark mass and D-meson decay constants from two-flavour lattice\n  QCD: We present a computation of the charm quark's mass and the leptonic D-meson\ndecay constants f_D and f_{D_s} in two-flavour lattice QCD with\nnon-perturbatively O(a) improved Wilson quarks. Our analysis is based on the\nCLS configurations at two lattice spacings (a=0.065 and 0.048 fm, where the\nlattice scale is set by f_K) and pion masses ranging down to ~ 190 MeV at\nL*m_pi > 4, in order to perform controlled continuum and chiral extrapolations\nwith small systematic uncertainties.",
        "positive": "Instantons and Fixed Point Actions in SU(2) Gauge Theory: We describe the properties of instantons in lattice gauge theory when the\naction is a fixed point action of some renormalization group transformation. We\npresent a theoretically consistent method for measuring topological charge\nusing an inverse renormalization group transformation. We show that, using a\nfixed point action, the action of smooth configurations with non-zero\ntopological charge is greater than or equal to its continuum value\n$8\\pi^2/g^2$."
    },
    {
        "anchor": "Physics development of web-based tools for use in hardware clusters\n  doing lattice physics: Jefferson Lab and MIT are developing a set of web-based tools within the\nLattice Hadron Physics Collaboration to allow lattice QCD theorists to treat\nthe computational facilities located at the two sites as a single\nmeta-facility. The prototype Lattice Portal provides researchers the ability to\nsubmit jobs to the cluster, browse data caches, and transfer files between\ncache and off-line storage. The user can view the configuration of the PBS\nservers and to monitor both the status of all batch queues as well as the jobs\nin each queue. Work is starting on expanding the present system to include job\nsubmissions at the meta-facility level (shared queue), as well as multi-site\nfile transfers and enhanced policy-based data management capabilities.",
        "positive": "Is the up-quark massless?: We report on determinations of the low-energy constants alpha5 and alpha8 in\nthe effective chiral Lagrangian at O(p^4), using lattice simulations with N_f=2\nflavours of dynamical quarks. Precise knowledge of these constants is required\nto test the hypothesis whether or not the up-quark is massless. Our results are\nobtained by studying the quark mass dependence of suitably defined ratios of\npseudoscalar meson masses and matrix elements. Although comparisons with an\nearlier study in the quenched approximation reveal small qualitative\ndifferences in the quark mass behaviour, numerical estimates for alpha5 and\nalpha8 show only a weak dependence on the number of dynamical quark flavours.\nOur results disfavour the possibility of a massless up-quark, provided that the\nquark mass dependence in the physical three-flavour case is not fundamentally\ndifferent from the two-flavour case studied here."
    },
    {
        "anchor": "K^0--\\bar{K}^0 mixing in full lattice QCD: There are at least two methods to calculate $ B_K $ with staggered fermions:\none is the two spin trace formalism and the other is the one spin trace\nformalism. We have performed numerical simulations on a $ 16^3 \\times 40 $\nlattice in full QCD with $ \\beta = 5.7 $ and a dynamical quark mass 0.01 in\nlattice units. We try various sources to select only the pseudo-Goldstone\nbosons and compare the various results.",
        "positive": "Surface operator study in SU(2) gauge field theory: The surface operator in an SU(2) gauge field theory is studied. We analyze\nAbelian projection of the SU(2) symmetry to the U(1) group calculating the\nsurface parameter. The surface parameter dependence on the surface area and\nvolume is studied in confinement and deconfinement phases. It is shown the\nspatial and temporal surface operators exhibit nontrivial area dependence in\nthe confinement and deconfinement phases. It is shown also that there is no\nvolume law for the operators defined on a cubic surface."
    },
    {
        "anchor": "Muon g-2 with overlap valence fermions: We present a lattice calculation of the leading order (LO) hadronic vacuum\npolarization (HVP) contribution to the muon anomalous magnetic moment for the\nconnected light and strange quarks, $a^{\\rm W}_{{\\rm con}, l/s}$ in the widely\nused window $t_0=0.4~\\mathrm{fm}$, $t_1=1.0~\\mathrm{fm}$,\n$\\Delta=0.15~\\mathrm{fm}$, and also of $a^{\\rm S}_{{\\rm con}, l/s}$ in the\nshort distance region. We use overlap fermions on 4 physical-point ensembles.\nTwo 2+1 flavor RBC/UKQCD ensembles use domain wall fermions (DWF) and Iwasaki\ngauge actions at $a = 0.084$ and 0.114 fm, and two 2+1+1 flavor MILC ensembles\nuse the highly improved staggered quark (HISQ) and Symanzik gauge actions at $a\n= 0.088$ and 0.121 fm. We have incorporated infinite volume corrections from 3\nadditional DWF ensembles at ${\\rm L}$ = 4.8, 6.4 and 9.6 fm and physical pion\nmass. For $a^{\\rm W}_{{\\rm con}, l}$, we find that our results on the two\nsmaller lattice spacings are consistent with those using the unitary setup, but\nthose at the two coarser lattice spacings are slightly different. Eventually,\nwe predict $a^{\\rm W}_{{\\rm con}, l}=206.7(1.5)(1.0)$ and $a^{\\rm W}_{{\\rm\ncon}, s}=26.8(0.1)(0.3)$, using linear extrapolation in $a^2$, with systematic\nuncertainties estimated from the difference of the central values from the\nRBC/UKQCD and MILC ensembles.",
        "positive": "Deconfining Chiral Transition in QCD on the Lattice: The deconfining chiral transition in finite-temperature QCD is studied on the\nlattice using Wilson quarks. After discussing the nature of chiral limit with\nWilson quarks, we first study the case of two degenerate quarks $N_F=2$, and\nfind that the transition is smooth in the chiral limit on both $N_t=4$ and 6\nlattices. For $N_F=3$, on the other hand, clear two state signals are observed\nfor $m_q \\simm{<} 140$ MeV on $\\nt=4$ lattices. For a more realistic case of\n$N_F=2+1$, i.e.\\ two degenerate u and d-quarks and a heavier s-quark, we study\nthe cases $m_s \\simeq 150$ and 400 MeV with $m_u = m_d \\simeq 0$: In contrast\nto a previous result with staggered quarks, clear two state signals are\nobserved for both cases, suggesting a first order QCD phase transition in the\nreal world."
    },
    {
        "anchor": "Baryon interactions from lattice QCD with physical masses ---S=-3\n  sector: XiSigma and XiLambda-XiSigma---: We present lattice QCD results of baryon-baryon potentials in S=-3 sector,\ni.e., \\Xi\\Sigma (I=3/2) potentials and \\Xi\\Lambda-\\Xi\\Sigma coupled channel\npotentials (I=1/2) by using the 2+1 flavor gauge configurations with almost the\nphysical quark masses generated on 96^4 lattice with 1/a \\simeq 2.3 GeV and L =\n96a \\simeq 8.1 fm where m_pi \\simeq 146 MeV and m_K \\simeq 525 MeV. These\npotentials are obtained based on the time-dependent HAL QCD method with a\nnon-relativistic approximation. Qualitative behaviors of the results are found\nto be consistent with those in the flavor SU(3) limit.",
        "positive": "QCD Thermodynamics from the Lattice: We review the current methods and results of lattice simulations of quantum\nchromodynamics at nonzero temperatures and densities. The review is intended to\nintroduce the subject to interested nonspecialists and beginners. It includes a\nbrief overview of lattice gauge theory, a discussion of the determination of\nthe crossover temperature, the QCD phase diagram at zero and nonzero densities,\nthe equation of state, some in-medium properties of hadrons including\ncharmonium, and some plasma transport coefficients."
    },
    {
        "anchor": "Thermal phase structure of dimensionally reduced super-Yang--Mills: We present our current results from ongoing lattice investigations of the\nBerenstein--Maldacena--Nastase deformation of maximally supersymmetric\nYang--Mills quantum mechanics. We focus on the thermal phase structure of this\ntheory, which depends on both the temperature $T$ and the deformation parameter\n$\\mu$, through the dimensionless ratios $T / \\mu$ and $g = \\lambda / \\mu^3$\nwith $\\lambda$ the 't Hooft coupling. We determine the critical $T / \\mu$ of\nthe confinement transition for couplings $g$ that span three orders of\nmagnitude, to connect weak-coupling perturbative calculations and large-$N$\ndual supergravity predictions in the strong-coupling limit. Analyzing multiple\nlattice sizes up to $N_{\\tau} = 24$ and numbers of colors up to $N = 16$ allows\ninitial checks of the large-$N$ continuum limit.",
        "positive": "Exploring Lattice Quantum Chromodynamics by Cooling: The effect of cooling on a number of observables is calculated in SU(2)\nlattice gauge theory. The static quark-antiquark potential and spin-dependent\ninteractions are studied, and the topological charge is monitored. The chiral\nsymmetry breaking order parameter $\\langle \\overline{\\chi}\\chi \\rangle$ and\nmeson correlators are calculated using staggered fermions. Interactions on the\ndistance scale of a few lattice spacings are found to be essentially eliminated\nby cooling, including the spin-dependent potentials. $\\langle\n\\overline{\\chi}\\chi \\rangle$ and meson correlators up to time separations of\nseveral lattice spacings relax very quickly to their free-field values. At\nlarger times, there is evidence of a difference between the pseudoscalar and\nvector channels. A fit to the pseudoscalar correlation function yields ``mass''\nvalues about $2/3$ (in lattice units) of the uncooled masses. These results\nraise the question of how to reconcile the large-time behavior of the hadron\ncorrelators with the fact that the spin-dependent potentials and $\\langle\n\\overline{\\chi}\\chi \\rangle$ essentially disappear (in lattice units) after\nonly a small amount of cooling."
    },
    {
        "anchor": "Pad\u00e9 - Z$_2$ Estimator of Determinants: We introduce the Pad\\'e--Z$_2$ (PZ) stochastic estimator for calculating\ndeterminants and determinant ratios. The estimator is applied to the\ncalculation of fermion determinants from the two ends of the Hybrid Monte Carlo\ntrajectories with pseudofermions. Our results on the $8^3 \\times 12$ lattice\nwith Wilson action show that the statistical errors from the stochastic\nestimator can be reduced by more than an order of magnitude by employing an\nunbiased variational subtraction scheme which utilizes the off-diagonal\nmatrices from the hopping expansion. Having been able to reduce the error of\nthe determinant ratios to about 20 % with a relatively small number of noise\nvectors, this may become a feasible algorithm for simulating dynamical fermions\nin full QCD. We also discuss the application to the density of states in\nHamiltonian systems.",
        "positive": "On the removal of the trace mode in lattice ${\\cal N}=4$ super\n  Yang-Mills theory: Twisted and orbifold formulations of lattice ${\\cal N}=4$ super Yang-Mills\ntheory which possess an exact supersymmetry require a $U(N)=SU(N)\\otimes U(1)$\ngauge group. In the naive continuum limit, the $U(1)$ modes trivially decouple\nand play no role in the theory. However, at non-zero lattice spacing they\ncouple to the $SU(N)$ modes and can drive instabilities in the lattice theory.\nFor example, it is well known that the lattice $U(1)$ theory undergoes a phase\ntransition at strong coupling to a chirally broken phase. An improved action\nthat suppresses the fluctuations in the $U(1)$ sector was proposed in\narXiv:1505.03135 . Here, we explore a more aggressive approach to the problem\nby adding a term to the action which can entirely suppress the $U(1)$ mode. The\npenalty is that the new term breaks the $\\mathcal{Q}$-exact lattice\nsupersymmetry. However, we argue that the term is $1/N^2$ suppressed and the\nexistence of a supersymmetric fixed point in the planar limit ensures that any\nSUSY-violating terms induced in the action possess couplings that also vanish\nin this limit. We present numerical results on supersymmetric Ward identities\nconsistent with this conclusion."
    },
    {
        "anchor": "Euclidean correlators at imaginary spatial momentum and their relation\n  to the thermal photon emission rate: The photon emission rate of a thermally equilibrated system is determined by\nthe imaginary part of the in-medium retarded correlator of the electromagnetic\ncurrent transverse to the spatial momentum of the photon. In a\nLorentz-covariant theory, this correlator can be parametrized by a scalar\nfunction ${\\cal G}_R(u\\cdot {\\cal K},{\\cal K}^2)$, where $u$ is the fluid\nfour-velocity and ${\\cal K}$ corresponds to the momentum of the photon. We\npropose to compute the analytic continuation of ${\\cal G}_R(u\\cdot {\\cal\nK},{\\cal K}^2)$ at fixed, vanishing virtuality ${\\cal K}^2$, to imaginary\nvalues of the first argument, $u\\cdot {\\cal K}= i\\omega_n$. At these\nkinematics, the retarded correlator is equal to the Euclidean correlator\n$G_E(\\omega_n, k=i\\omega_n)$, whose first argument is the Matsubara frequency\nand the second is the spatial momentum. The Euclidean correlator, which is\ndirectly accessible in lattice QCD simulations, must be given an imaginary\nspatial momentum in order to realize the photon on-shell condition. Via a\nonce-subtracted dispersion relation that we derive in a standard way at fixed\n${\\cal K}^2=0$, the Euclidean correlator with imaginary spatial momentum is\nrelated to the photon emission rate. The relation allows for a more direct\nprobing of the real-photon emission rate of the quark-gluon plasma in lattice\nQCD than the dispersion relations which have been used so far, the latter being\nat fixed spatial photon momentum $k$ and thus involving all possible\nvirtualities of the photon.",
        "positive": "Density distributions in the $B$ meson: We report on a two-flavor lattice QCD study of the axial, charge and matter\ndistributions of the $B$ meson and its first radial excitation. As our\nframework is the static limit of Heavy Quark Effective Theory (HQET), taking\ntheir Fourier transform gives access to several form factors at the kinematical\npoint $q^2=0$. Moreover they provide some useful information on the nature of\nan excited state, i.e. a radial excitation of a quark-antiquark bound state or\na multihadron state."
    },
    {
        "anchor": "Nucleon electromagnetic form factors and axial charge from CLS\n  $N_\\mathrm{f}=2+1$ ensembles: We present preliminary results on the electromagnetic form factors and axial\ncharge of the nucleon from ensembles generated by the CLS effort with\n$N_\\mathrm{f}=2+1$ flavours of non-perturbatively $\\mathrm{O}(a)$-improved\nWilson fermions and open temporal boundary conditions. Systematic effects due\nto excited-state contamination are accounted for using both two-state fits and\nthe method of summed operator insertions. This exploratory analysis\ndemonstrates the viability of obtaining precision baryon observables with\n$N_\\mathrm{f}=2+1$ flavours of Wilson fermions on fine lattices, aiming towards\ncontrolled chiral and continuum limits in the future.",
        "positive": "Wilson mass dependence of the overlap topological charge density: The dependence of the overlap Dirac operator on the Wilson-mass regulator\nparameter is studied through calculations of the overlap topological charge\ndensities at a variety of Wilson-mass values. In this formulation, the\nWilson-mass is used in the negative mass region and acts as a regulator\ngoverning the scale at which the Dirac operator is sensitive to topological\naspects of the gauge field. We observe a clear dependence on the value of the\nWilson-mass and demonstrate how these values can be calibrated against a finite\nnumber of stout-link smearing sweeps. The overlap topological charge density is\nalso computed using a pre-smeared gauge field for the input kernel. We show how\napplying the overlap operator leads to further filtering of the gauge field.\nThe results suggest that the freedom typically associated with smearing\nalgorithms, through the variable number of sweeps, also exists in the overlap\noperator, through the variable Wilson-mass parameter."
    },
    {
        "anchor": "The QCD chiral transition, $\\ua$ symmetry and the Dirac spectrum using\n  domain wall fermions: We report on a study of the finite-temperature QCD transition region for\ntemperatures between 139 and 196 MeV, with a pion mass of 200 MeV and two\nspace-time volumes: $24^3\\times8$ and $32^3\\times8$, where the larger volume\nvaries in linear size between 5.6 fm (at T=139 MeV) and 4.0 fm (at T=195 MeV).\nThese results are compared with the results of an earlier calculation using the\nsame action and quark masses but a smaller, $16^3\\times8$ volume. The chiral\ndomain wall fermion formulation with a combined Iwasaki and dislocation\nsuppressing determinant ratio gauge action are used. This lattice action\naccurately reproduces the $\\sua$ and $\\ua$ symmetries of the continuum. Results\nare reported for the chiral condensates, connected and disconnected\nsusceptibilities and the Dirac eigenvalue spectrum. We find a pseudo-critical\ntemperature, $T_c$, of approximately 165 MeV consistent with previous results\nand strong finite volume dependence below $T_c$. Clear evidence is seen for\n$\\ua$ symmetry breaking above $T_c$ which is quantitatively explained by the\nmeasured density of near-zero modes in accordance with the dilute instanton gas\napproximation.",
        "positive": "Calculation of the pion charge radius from an improved model-independent\n  method: We propose a new improved model-independent method for calculating the pion\ncharge radius. In a recently-proposed model-independent method for the pion\ncharge radius, we find it difficult to compute the pion charge radius for small\npole mass $M_{\\rm{pole}}^2$ and volume due to systematic errors coming from\nfinite volume effect and higher-order contamination of the Taylor expansion of\nthe form factor. We circumvent this difficulty by introducing a new appropriate\nfunction and propose a modified method that can calculate the pion charge\nradius with less systematic errors in the small $M_{\\rm{pole}}^2$ and volume\ncases. As preliminary results, we check that our improved model-independent\nmethod works well on a mockup data and also an actual lattice QCD data at the\npion mass of 0.51 GeV."
    },
    {
        "anchor": "Topological susceptibility in full QCD with Ginsparg-Wilson fermions: We show that, if the formula for the topological charge density operator\nsuggested by fermions obeying the Ginsparg-Wilson relation is employed, it is\npossible to give a precise and unambiguous definition of the topological\nsusceptibility in full QCD, chi_tL, for finite quark masses on the lattice. The\nlattice expression of chi_tL looks like the formal continuum one, in the sense\nthat no power divergent subtractions are needed for its proper definition. As a\nconsequence, the small mass behaviour of chi_tL leads directly to a\nmultiplicative renormalizable definition of the chiral condensate that does not\nrequire any power divergent subtraction.",
        "positive": "Flavor diagonal tensor charges of the nucleon from 2+1+1 flavor lattice\n  QCD: We present state-of-the-art results for the matrix elements of flavor\ndiagonal tensor operators within the nucleon state. The calculation of the\ndominant connected contribution is done using eleven ensembles of gauge\nconfigurations generated by the MILC Collaboration using the highly improved\nstaggered quark (HISQ) action with 2+1+1 dynamical flavors. The calculation of\nthe disconnected contributions is done using seven (six) ensembles for the\nstrange (light) quarks. These high-statistics simulations allowed us to address\nvarious systematic uncertainties. A simultaneous fit in the lattice spacing and\nthe light-quark mass is used to extract the tensor charges in the continuum\nlimit and at $M_\\pi=135$ MeV. Results for the proton in the $\\overline{MS}$\nscheme at 2~GeV are: $g_T^u = 0.784(28)(10)$, $g_T^d = -0.204(11)(10)$ and\n$g_T^s = -0.0027(16)$. Implications of these results for constraining the quark\nelectric dipole moments and their contributions to the neutron electric dipole\nmoment are discussed."
    },
    {
        "anchor": "Variational method with staggered fermions: The variational method is used widely for determining eigenstates of the QCD\nhamiltonian for actions with a conventional transfer matrix, e.g., actions with\nimproved Wilson fermions. An alternative lattice fermion formalism, staggered\nfermions, does not have a conventional single-time-step transfer matrix.\nNonetheless, with a simple modification, the variational method can also be\napplied to that formalism. In some cases the method also provides a mechanism\nfor separating the commonly paired parity-partner states. We discuss the\nextension to staggered fermions and illustrate it by applying it to the\ncalculation of the spectrum of charmed-antistrange mesons consisting of a\nclover charm quark and a staggered strange antiquark.",
        "positive": "New issues for Numerical Stochastic Perturbation Theory: First attempts in the application of Numerical Stochastic Perturbation Theory\n(NSPT) to the problem of pushing one loop further the computation of SU(3)\n(SU(2)) pertubative beta function (in different schemes) are reviewed and the\nrelevance of such a computation is discussed. Other issues include the proposal\nof a different strategy for gauge-fixed NSPT computations in lattice QCD."
    },
    {
        "anchor": "Form factors for Lambda_b -> Lambda transitions from lattice QCD: The rare baryonic decays $\\Lambda_b \\to \\Lambda \\mu^+ \\mu^-$ and $\\Lambda_b\n\\to \\Lambda \\gamma$ can complement rare $B$ meson decays in constraining models\nof new physics. In this work, we calculate the relevant $\\Lambda_b \\to \\Lambda$\ntransition form factors at leading order in heavy-quark effective theory using\nlattice QCD. Our analysis is based on RBC/UKQCD gauge field ensembles with 2+1\nflavors of domain-wall fermions, and with lattice spacings of $a\\approx 0.11$\nfm and $a\\approx 0.08$ fm. We compute appropriate ratios of three-point and\ntwo-point correlation functions for a wide range of source-sink separations,\nand extrapolate to infinite separation in order to eliminate excited-state\ncontamination. We then extrapolate the form factors to the continuum limit and\nto the physical values of the light-quark masses.",
        "positive": "The isentropic equation of state of 2-flavor QCD: Using Taylor expansions of the pressure obtained previously in studies of\n2-flavor QCD at non-zero chemical potential we calculate expansion coefficients\nfor the energy and entropy densities up to ${\\cal O}(\\mu_q^6)$ in the quark\nchemical potential. We use these series in $\\mu_q/T$ to determine lines of\nconstant entropy per baryon number ($S/N_B$) that characterize the expansion of\ndense matter created in heavy ion collisions. In the high temperature regime\nthese lines are found to be well approximated by lines of constant $\\mu_q/T$.\nIn the low temperature phase, however, the quark chemical potential is found to\nincrease with decreasing temperature. This is in accordance with resonance gas\nmodel calculations. Along the lines of constant $S/N_B$ we calculate the energy\ndensity and pressure. Within the accuracy of our present analysis we find that\nthe ratio $p/\\epsilon$ for $T>T_0$ as well as the softest point of the equation\nof state, $(p/\\epsilon)_{min}\\simeq 0.075$, show no significant dependence on\n$S/N_B$."
    },
    {
        "anchor": "Twisted mass QCD and the FNAL heavy quark formalism: At tree level, I discuss modifying the FNAL heavy quark formalism to include\na twisted mass term. I find that at maximal twist the so called KLM factor is\nindependent of the heavy mass.",
        "positive": "Localisation of Dirac eigenmodes and confinement in gauge theories: the\n  Roberge-Weiss transition: Ample numerical evidence from lattice calculations shows a strong connection\nbetween the confining properties of gauge theories at finite temperature and\nthe localisation properties of the low-lying Dirac eigenmodes. In this\ncontribution we discuss recent progress on this topic, focussing on results for\nQCD at imaginary chemical potential ${\\mu}_I/T = \\pi$ at temperatures above the\nRoberge-Weiss transition temperature. These confirm the general picture of low\nmodes turning from delocalised to localised at the deconfinement transition, in\na previously unexplored setup with a genuine, physical transition in the\npresence of dynamical fermions. This further supports the use of Dirac\neigenmodes as a tool to investigate the mechanisms behind confinement and the\ndeconfinement transition."
    },
    {
        "anchor": "SU(N) gauge theories in 3+1 dimensions: glueball spectrum, string\n  tensions and topology: We calculate the low-lying glueball spectrum, some string tensions and some\nproperties of topology and the running coupling for SU(N) lattice gauge\ntheories in 3+1 dimensions. We do so for N = 2,3,...12, using lattice\nsimulations with the Wilson plaquette action, and for glueball states in all\nthe representations of the cubic rotation group, for both values of parity and\ncharge conjugation. We extrapolate these results to the continuum limit of each\ntheory and then to N=infinity. For a number of these states we are able to\nidentify their continuum spins with very little ambiguity. We calculate the\nfundamental string tension and k=2 string tension and investigate the N\ndependence of the ratio. Using the string tension as the scale, we calculate\nthe running of a lattice coupling and confirm that g(a)**2 varies as 1/N for\nconstant physics as N->oo. We fit our calculated values of the string tension\nwith the 3-loop beta-function, and extract a value for Lambda-MSbar, in units\nof the string tension, for all our values of N, including SU(3). We calculate\nthe topological charge Q for N=2,..,6 where it fluctuates sufficiently for a\nplausible estimate of the continuum topological susceptibility. We also\ncalculate the renormalisation of the lattice topological charge, ZQ(beta), for\nall our SU(N) gauge theories, using a standard definition of the charge, and we\nprovide interpolating formulae, which may be useful in estimating the\nrenormalisation of the lattice theta parameter. We provide quantitative results\nfor how the topological charge `freezes' with decreasing lattice spacing and\nwith increasing N, and show how we cicumvent this issue in our calculations.",
        "positive": "New $N_f=2$ Pseudofermion Action for Monte-Carlo Simulation of Lattice\n  Field Theory with Domain-Wall Fermions: We construct a novel $ N_f = 2 $ pseudofermion action for Monte-Carlo\nsimulation of lattice gauge theory with domain-wall fermions (DWF), of which\nthe effective four-dimensional lattice Dirac operator is equal to the\noverlap-Dirac operator with the argument of the sign function equal to $ H = c\n\\gamma_5 D_w (1 + d D_w)^{-1} $, where $ c $ and $ d $ are parameters, and\n$D_w$ is the standard Wilson-Dirac operator plus a negative parameter $-m_0 \\;\n(0 < m_0 < 2)$. This new action is particularly useful for the challenging\nsimulations of lattice gauge theories with large $N_f = 2n $ DWF, on the large\nlattices, and in the strong-coupling regime."
    },
    {
        "anchor": "Lattice Calculation of the Proton Charge Radius: The charge radius of the proton has been measured in scattering and\nspectroscopy experiments using both electronic and muonic probes. The\nelectronic and muonic measurements are discrepant at $5\\sigma$, giving rise to\nwhat is known as the proton radius puzzle.\n  With the goal of resolving this, we introduce a novel method of using lattice\nQCD to determine the isovector charge radius -- defined as the slope of the\nelectric form factor at zero four-momentum transfer -- by introducing a mass\nsplitting between the up and down quarks. This allows us to access timelike\nfour-momentum transfers as well as spacelike ones, leading to potentially\nhigher accuracy in determining the form factor slope at $Q^2 = 0$ by\ninterpolation. In this preliminary study, we find a Dirac isovector radius\nsquared of $0.320 \\pm 0.074$ fm$^2$ at quark masses corresponding to $m_\\pi =\n450$ MeV. We compare the feasibility of this method with other approaches of\ndetermining the proton charge radius from lattice QCD.",
        "positive": "Combining Bayesian reconstruction entropy with maximum entropy method\n  for analytic continuations of matrix-valued Green's functions: The Bayesian reconstruction entropy is considered an alternative to the\nShannon-Jaynes entropy, as it does not exhibit the asymptotic flatness\ncharacteristic of the Shannon-Jaynes entropy and obeys the scale invariance. It\nis commonly utilized in conjunction with the maximum entropy method to derive\nspectral functions from Euclidean time correlators produced by lattice QCD\nsimulations. This study expands the application of the Bayesian reconstruction\nentropy to the reconstruction of spectral functions for Matsubara or\nimaginary-time Green's functions in quantum many-body physics. Furthermore, it\nextends the Bayesian reconstruction entropy to implement the positive-negative\nentropy algorithm, enabling the analytic continuations of matrix-valued Green's\nfunctions on an element-wise manner. Both the diagonal and off-diagonal\ncomponents of the matrix-valued Green's functions are treated equally.\nBenchmark results for the analytic continuations of synthetic Green's functions\nindicate that the Bayesian reconstruction entropy, when combined with the\npreblur trick, demonstrates comparable performance to the Shannon-Jaynes\nentropy. Notably, it exhibits greater resilience to noises in the input data,\nparticularly when the noise level is moderate."
    },
    {
        "anchor": "Lattice Perturbation Theory by Computer Algebra: A Three-Loop Result for\n  the Topological Susceptibility: We present a scheme for the analytic computation of renormalization functions\non the lattice, using a symbolic manipulation computer language. Our first\nnontrivial application is a new three-loop result for the topological\nsusceptibility.",
        "positive": "Large-$N$ limit of two-dimensional Yang--Mills theory with four\n  supercharges: We study the two-dimensional Yang--Mills theory with four supercharges in the\nlarge-$N$ limit. By using thermal boundary conditions, we analyze the internal\nenergy and the distribution of scalars. We compare their behavior to the\nmaximally supersymmetric case with sixteen supercharges, which is known to\nadmit a holographic interpretation. Our lattice results for the scalar\ndistribution show no visible dependence on $N$ and the energy at strong\ncoupling appears independent of temperature."
    },
    {
        "anchor": "Partially Quenched Chiral Condensates from the Replica Method: A large-N_f expansion is used to compute the partially quenched chiral\ncondensate of QCD in the microscopic finite-volume scaling region.",
        "positive": "Definitions of a static SU(2) color triplet potential: We discuss possibilities and problems to non-perturbatively define and\ncompute a static color triplet potential in SU(2) gauge theory. Numerical\nlattice results are presented and compared to analytical perturbative results."
    },
    {
        "anchor": "Monopole Loop Suppression and Loss of Confinement in Restricted Action\n  SU(2) Lattice Gauge Theory: The effect of restricting the plaquette ($1\\times 1$ Wilson loop) to be\ngreater than a certain cutoff is studied. The action considered is the standard\nWilson action with the addition of the plaquette restriction, which does not\naffect the continuum limit. A deconfining phase transition occurs as the cutoff\nis raised, even in the strong coupling limit. Abelian-projected monopoles in\nthe maximal abelian gauge are strongly suppressed by the action restriction.\nAnalysis of the steeply declining monopole loop distribution function indicates\nthat for cutoffs $c > 0.5$, large monopole loops which are any finite fraction\nof the lattice size do not exist in the infinite lattice limit. This would seem\nto imply the theory lacks confinement, which is consistent with a fixed point\nbehavior seen in the normalized fourth cumulant of the Polyakov loop.",
        "positive": "Discretization Effects in the $\u03b5$ Domain of QCD: At nonzero lattice spacing the QCD partition function with Wilson quarks\nundergoes either a second order phase transition to the Aoki phase for\ndecreasing quark mass or shows a first order jump when the quark mass changes\nsign. We discuss these phase transitions in terms of Wilson Dirac spectra and\nshow that the first order scenario can only occur in the presence of dynamical\nquarks while in the quenched case we can only have a transition to the Aoki\nphase. The exact microscopic spectral density of the non-Hermitian Wilson Dirac\noperator with dynamical quarks is discussed as well. We conclude with some\nremarks on discretization effects for the overlap Dirac operator."
    },
    {
        "anchor": "Logarithmic corrections to $\\mathbf{a^2}$ scaling in lattice Yang Mills\n  theory: We analyse the leading logarithmic corrections to the $a^2$ scaling of\nlattice artefacts in QCD, following the seminal work of Balog, Niedermayer and\nWeisz in the O(n) non-linear sigma model. Restricting our attention to\ncontributions from the action, the leading logarithmic corrections can be\ndetermined by the anomalous dimensions of a minimal on-shell basis of\nmass-dimension 6 operators. We present results for the SU(N) pure gauge theory.\nIn this theory the logarithmic corrections reduce the cutoff effects. These\ncomputations are the first step towards a study of full lattice QCD at\nO($a^2$), which is in progress.",
        "positive": "Prospects and status of quark mass renormalization in three-flavour QCD: We present the current status of a revised strategy to compute the running of\nrenormalized quark masses in QCD with three flavours of massless O(a) improved\nWilson quarks. The strategy employed uses the standard finite-size scaling\nmethod in the Schr\\\"odinger functional and accommodates for the\nnon-perturbative scheme-switch which becomes necessary at intermediate\nrenormalized couplings as discussed in [arXiv:1411.7648]."
    },
    {
        "anchor": "Flavor Symmetry and the Static Potential with Hypercubic Blocking: We introduce a new smearing transformation, the hypercubic (HYP) fat link.\nThe hypercubic fat link mixes gauge links within hypercubes attached to the\noriginal link only. Using quenched lattices at beta = 5.7 and 6.0 we show that\nHYP fat links improve flavor symmetry by an order of magnitude relative to the\nthin link staggered action. The static potential measured on HYP smeared\nlattices agrees with the thin link potential at distances r/a >= 2 and has\ngreatly reduced statistical errors. These quenched results will be used in\nforthcoming dynamical simulations of HYP staggered fermions.",
        "positive": "Systematics in nucleon matrix element calculations: The current status of calculations of simple nucleon structure observables is\nreviewed, with a focus on the axial charge. A major challenge is the\ncombination of an exponentially decaying signal-to-noise ratio and the need for\nlarge source-sink separations to eliminate excited-state contributions; efforts\nto understand and deal with this problem are the focus of the largest section\nof this review. Finite-volume effects and chiral extrapolation are also briefly\ndiscussed."
    },
    {
        "anchor": "Suppressing Curvature Fluctuations in Dynamical Triangulations: We study numerically the dynamical triangulation formulation of\ntwo-dimensional quantum gravity using a restricted class of triangulation,\nso-called minimal triangulations, in which only vertices of coordination number\n5, 6, and 7 are allowed. A real-space RG analysis shows that for pure gravity\n(central charge c = 0) this restriction does not affect the critical behavior\nof the model. Furthermore, we show that the critical behavior of an Ising model\ncoupled to minimal dynamical triangulations (c = 1/2) is still governed by the\nKPZ-exponents.",
        "positive": "The density of states approach to dense quantum systems: We develop a first-principle generalised density of state method for studying\nnumerically quantum field theories with a complex action. As a proof of\nconcept, we show that with our approach we can solve numerically the strong\nsign problem of the $Z_3$ spin model at finite density. Our results are\nconfirmed by standard simulations of the theory dual to the considered model,\nwhich is free from a sign problem. Our method opens new perspectives on ab\ninitio simulations of cold dense quantum systems, and in particular of\nYang-Mills theories with matter at finite densities, for which Monte Carlo\nbased importance sampling are unable to produce sufficiently accurate results."
    },
    {
        "anchor": "Gauge theories with fermions in the two-index symmetric representation: We summarize our recent work on gauge theories with two flavors of fermions\nin the two-index symmetric representation: SU(2) gauge theory with adjoint\nfermions, SU(3) with sextets, and SU(4) with ten-dimensional-representation\nfermions. All three systems have beta functions smaller than their perturbative\nvalue, approaching a fixed point near the expected two-loop zero. In all cases\nthe mass anomalous dimension is small, under 0.5.",
        "positive": "Quark mass anomalous dimension and $\u039b_{\\overline{\\textrm{MS}}}$\n  from the twisted mass Dirac operator spectrum: We investigate whether it is possible to extract the quark mass anomalous\ndimension and its scale dependence from the spectrum of the twisted mass Dirac\noperator in Lattice QCD. The answer to this question appears to be positive,\nprovided that one goes to large enough eigenvalues, sufficiently above the\nnon-perturbative regime. The obtained results are compared to continuum\nperturbation theory. By analyzing possible sources of systematic effects, we\nfind the domain of applicability of the approach, extending from an energy\nscale of around 1.5 to 4 GeV. The lower limit is dictated by physics\n(non-perturbative effects at low energies), while the upper bound is set by the\nultraviolet cut-off of present-day lattice simulations. The information about\nthe scale dependence of the anomalous dimension allows also to extract the\nvalue of the $\\Lambda_{\\overline{\\textrm{MS}}}$-parameter of 2-flavour QCD,\nyielding the value $303(13)(25)$ MeV, where the first error is statistical and\nthe second one systematic. We use gauge field configuration ensembles generated\nby the European Twisted Mass Collaboration (ETMC) with 2 flavours of dynamical\ntwisted mass quarks, at 4 lattice spacings in the range between around 0.04 and\n0.08 fm."
    },
    {
        "anchor": "Phases of many flavors QCD : Lattice results: This note is based on our recent results on QCD with varying number of\nflavors of fundamental fermions. Topics include unusual, strong dynamics in the\npreconformal, confining phase, the physics of the conformal window and the role\nof ab-initio lattice simulations in establishing our current knowledge of the\nphases of many flavor QCD",
        "positive": "QCDLAB: Designing Lattice QCD Algorithms with MATLAB: This paper introduces QCDLAB, a design and research tool for lattice QCD\nalgorithms. The tool, a collection of MATLAB functions, is based on a\n``small-code'' and a ``minutes-run-time'' algorithmic design philosophy. The\npresent version uses the Schwinger model on the lattice, a great\nsimplification, which shares many features and algorithms with lattice QCD. A\ntypical computing project using QCDLAB is characterised by short codes, short\nrun times, and the ability to make substantial changes in a few seconds. QCDLAB\n1.0 can be downloaded from the QCDLAB project homepage {\\tt\nhttp://phys.fshn.edu.al/qcdlab.html}."
    },
    {
        "anchor": "SU(2) gluon propagator on a coarse anisotropic lattice: We calculated the SU(2) gluon propagator in Landau gauge on an anisotropic\ncoarse lattice with the improved action. The standard and the improved scheme\nare used to fix the gauge in this work. Even on the coarse lattice the lattice\ngluon propagator can be well described by a function of the continuous\nmomentum. The effect of the improved gauge fixing scheme is found not to be\napparent. Based on the Marenzoni's model, the mass scale and the anomalous\ndimension are extracted and can be reasonably extrapolated to the continuum\nlimit with the values $\\alpha\\sim 0.3$ and $M\\sim 600MeV$. We also extract the\nphysical anisotropy $\\xi$ from the gluon propagator due to the explicit $\\xi$\ndependence of the gluon propagator.",
        "positive": "The sign problem and Abelian lattice duality: For a large class of Abelian lattice models with sign problems, including the\ncase of non-zero chemical potential, duality maps models with complex actions\ninto dual models with real actions. For extended regions of parameter space,\ncalculable for each model, duality resolves the sign problem for both analytic\nmethods and computer simulations. Explicit duality relations are given for\nmodels for spin and gauge models based on Z(N) and U(1) symmetry groups. The\ndual forms are generalizations of the Z(N) chiral clock model and the lattice\nFrenkel-Kontorova model, respectively. From these equivalences, rich sets of\nspatially-modulated phases are found in the strong-coupling region of the\noriginal models."
    },
    {
        "anchor": "Casimir scaling or flux counting?: Potentials between two static sources in various representations of the SU(3)\ngauge group are determined on anisotropic 3+1 dimensional lattices. Strong\nevidence in favour of \"Casimir scaling\" is found.",
        "positive": "Constraints on Disconnected Contributions in $\u03c0\u03c0$ Scattering: The accuracy of the lattice QCD computation of hadron-hadron scattering at\nlow isospin depends critically on the ability to compute correlation functions\nwith fermionic disconnected Wick contractions. This happens, for instance, in\nisospin $I=0$ $\\pi\\pi$ scattering, which receives contributions from\nrectangular and vacuum types of contractions among other easier calculable\nones. Combining L\\\"{u}scher's formula and partially-quenched chiral\nperturbation theory, we provide precise theory predictions of the discrete\nenergy levels extracted from specific linear combinations of lattice\ncorrelation functions corresponding to various types of contractions.\nExpressions are provided for extracting the unphysical low-energy constants in\nthe partially-quenched chiral perturbation theory from the energy levels for\nthese contractions. The predictions for the rectangular and vacuum contractions\nmay serve as solid tests of the accuracy for existing and future lattice\nstudies of $\\pi\\pi$ scattering."
    },
    {
        "anchor": "Inclusive hadronic decay rate of the $\u03c4$ lepton from lattice QCD: Inclusive hadronic decays of the $\\tau$ lepton are very interesting from the\nphenomenological point of view since they give access to the CKM matrix\nelements $V_{ud}$ and $V_{us}$. In this paper, for the first time, by employing\nthe HLT method for hadronic smeared spectral densities we compute on the\nlattice the inclusive decay rate of the processes $\\tau \\to X_{ud}\\, \\nu_\\tau$,\nwhere $X_{ud}$ is a generic hadronic state with $\\bar{u} d$ flavor quantum\nnumbers. Our computation, which avoids any recourse to OPE and/or perturbative\napproximations, is carried out in isospin symmetric $N_{f}=2+1+1$ lattice QCD\nat physical quark masses, using ensembles produced by the ETMC at three lattice\nspacings and two volumes. All uncertainties, except for isospin breaking\neffects, are taken into account and a result with a subpercent error is\nobtained for $|V_{ud}|$, which is nicely consistent with the current world\naverage. These findings validate our approach and also motivate the inclusion\nof isospin breaking corrections and its extension to the inclusive decay $\\tau\n\\to X_{us}\\, \\nu_\\tau$, paving the way towards a high-precision first\nprinciples determination of $|V_{us}|$ and $|V_{ud}|$ from inclusive $\\tau$\ndecay.",
        "positive": "A Method to Extract Charged Hadron Properties from Lattice QCD in\n  Magnetic Fields: By analyzing the external field dependence of correlation functions, the\nmagnetic properties of hadrons can be determined using lattice QCD in magnetic\nfields. To compute the magnetic moments and polarizabilities of charged\nhadrons, for example, one requires sufficiently weak magnetic fields. Such\nfield strengths, however, lead to closely spaced Landau levels that are not\nstraightforwardly resolved using standard lattice spectroscopy. Focusing on\ncharged spinless hadrons, we introduce a simple projection technique that can\nbe used to isolate the lowest Landau level. As the technique requires the\nexplicit coordinate-space wave-function, we investigate the extent to which the\ncontinuum, infinite volume wave-function can be employed. We find that, in\npractice, the effects of discretization can be handled using a perturbative\nexpansion about the continuum. Finite volume corrections are taken into account\nby using the discrete magnetic translational invariance of the torus. We show\nthat quantized magnetic fields can lead to pernicious volume effects which\ndepend on the magnetic flux quantum, rather than on the lattice volume."
    },
    {
        "anchor": "Form and index of Ginsparg-Wilson fermions: We clarify the questions rised by a recent example of a lattice Dirac\noperator found by Chiu. We show that this operator belongs to a class based on\nthe Cayley transformation and that this class on the finite lattice generally\ndoes not admit a nonvanishing index, while in the continuum limit, due to\noperator properties in Hilbert space, this defect is no longer there. Analogous\nobservations are made for the chiral anomaly. We also elaborate on various\naspects of the underlying sum rule for the index.",
        "positive": "Lattice study of electromagnetic conductivity of quark-gluon plasma in\n  external magnetic field: We study the electromagnetic (e.m.) conductivity of QGP in a magnetic\nbackground by lattice simulations with $N_f = 2+1$ dynamical rooted staggered\nfermions at the physical point. We study the correlation functions of the\ne.m.~currents at $T=200,\\,250$\\,MeV and use the Tikhonov approach to extract\nthe conductivity. This is found to rise with the magnetic field in the\ndirection parallel to it and to decrease in the transverse direction, giving\nevidence for both the Chiral Magnetic Effect and the magnetoresistance\nphenomenon in QGP. We also estimate the chiral charge relaxation time in QGP."
    },
    {
        "anchor": "Update on $\\varepsilon_K$ with lattice QCD inputs: We report updated results for $\\varepsilon_K$, the indirect CP violation\nparameter in neutral kaons, which is evaluated directly from the standard model\nwith lattice QCD inputs. We use lattice QCD inputs to fix $\\bar{B}_K$,\n$|V_{cb}|$, $\\xi_0$, $\\xi_2$, $|V_{us}|$, and $m_c(m_c)$. Since Lattice 2016,\nthe UTfit group has updated the Wolfenstein parameters in the angle-only-fit\nmethod, and the HFLAV group has also updated $|V_{cb}|$. Our results show that\nthe evaluation of $\\varepsilon_K$ with exclusive $|V_{cb}|$ (lattice QCD\ninputs) has $4.0\\sigma$ tension with the experimental value, while that with\ninclusive $|V_{cb}|$ (heavy quark expansion based on OPE and QCD sum rules)\nshows no tension.",
        "positive": "Fractional Inversion in Krylov Space: The fractional inverse $M^{-\\gamma}$ (real $\\gamma >0$) of a matrix $M$ is\nexpanded in a series of Gegenbauer polynomials. If the spectrum of $M$ is\nconfined to an ellipse not including the origin, convergence is exponential,\nwith the same rate as for Chebyshev inversion. The approximants can be improved\nrecursively and lead to an iterative solver for $M^\\gamma x = b$ in Krylov\nspace. In case of $\\gamma = 1/2$, the expansion is in terms of Legendre\npolynomials, and rigorous bounds for the truncation error are derived."
    },
    {
        "anchor": "Mesons upon low-lying Dirac mode exclusion: We study the isoscalar and isovector $J=0,1$ mesons with the overlap operator\nwithin two flavour lattice QCD. After subtraction of the lowest-lying Dirac\neigenmodes from the valence quark propagator all disconnected contributions\nvanish and all possible point-to-point $J=0$ correlators become identical,\nsignaling a simultaneous restoration of both $SU(2)_L \\times SU(2)_R$ and\n$U(1)_A$ symmetries. The ground states of the $\\pi,\\sigma,a_0,\\eta$ mesons do\nnot survive this truncation. All possible $J=1$ states have a very clean\nexponential decay and become degenerate, demonstrating a $SU(4)$ symmetry of a\ndynamical QCD-like string.",
        "positive": "Accelerating Twisted Mass LQCD with QPhiX: We present the implementation of twisted mass fermion operators for the QPhiX\nlibrary. We analyze the performance on the Intel Xeon Phi (Knights Corner)\ncoprocessor as well as on Intel Xeon Haswell CPUs. In particular, we\ndemonstrate that on the Xeon Phi 7120P the Dslash kernel is able to reach 80\\%\nof the theoretical peak bandwidth, while on a Xeon Haswell E5-2630 CPU our\ngenerated code for the Dslash operator with AVX2 instructions outperforms the\ncorresponding implementation in the tmLQCD library by a factor of $\\sim\n5\\times$ in single precision. We strong scale the code up to 6.8 (14.1) Tflops\nin single (half) precision on 64 Xeon Haswell CPUs."
    },
    {
        "anchor": "Fermion propagators in QED3 with velocity anisotropies: QED3 with fermi and gap anisotropies is considered to be a candidate\neffective field theory of high temperature superconductors. Simulations of a\nvariant of the theory have demonstrated that there is evidence consistent with\na phase transition to a chirally restored phase as the velocity anisotropy\nincreases, and that the correlation lengths of pions in spatial directions\nbehave in a manner consistent with the anisotropy being a relevant parameter of\nthe theory. We present the first measurements of the fermion propagator in\nLandau gauge for this theory and suggest that the structure of this theory is\nmore complex than previously thought.",
        "positive": "Surface states and chiral symmetry on the lattice: In a Hamiltonian formalism we study chiral symmetry for lattice Fermions\nformulated in terms of Shockley surface states bound to a wall in an extra\nspatial dimension. For hadronic physics this provides a natural scheme for\ntaking quark masses to zero without requiring a precise tuning of parameters.\nWe illustrate the chiral anomaly as a flow of states in this extra dimension.\nWe discuss two alternatives for extending the picture to a chiral coupling of\ngauge fields to such Fermions; one with a small explicit breaking of gauge\nsymmetry and one one with heavy mirror Fermions."
    },
    {
        "anchor": "The road to solving the Gribov problem of the center vortex model in\n  quantum chromo dynamics: The center vortex model of the QCD vacuum is very successful in explaining\nthe non-perturbative properties of QCD, especially confinement, chiral symmetry\nbreaking and the topological charge of vacuum configurations. On the other\nhand, the center vortex model still suffers from a Gribov problem: Direct\nmaximal center gauge and center projection can lead to an underestimation of\nthe string tension in smooth configurations or after persistent simulated\nannealing. We discuss methods to identify center regions, whose boundaries\nevaluate to center elements, and want to improve the vortex detection: these\nregions might help to recognize vortices in configurations where maximal center\ngauge lost the vortex finding property.",
        "positive": "Recent progress in the theory of random surfaces and simplicial quantum\n  gravity: Some of the recent developments in the theory of random surfaces and\nsimplicial quantum gravity is reviewed. For 2d quantum gravity this includes\nthe failure of Regge calculus, our improved understanding of the $c>1$ regime,\nsome surprises for q-state Potts models with $q > 4$, attempts to use\nrenormalization group techniques, new critical behavior of random surface\nmodels with extrinsic curvature and improved algorithms. For simplicial quantum\ngravity in higher dimensions it includes a discussion of the exponential\nentropy bound needed for the models to be well defined, the question of\n``computational ergodicity'' and the question of how to extract continuum\nbehavior from the lattice simulations."
    },
    {
        "anchor": "Thermalization algorithms for classical gauge theories: I propose a method, based on a set of Langevin equations, for bringing\nclassical gauge theories to thermal equilibrium while respecting the set of\nGauss' constraints exactly. The algorithm is described in detail for the SU(2)\ngauge theory with or without the Higgs doublet. As an example of application,\ncanonical average of the maximal Lyapunov exponent is computed for the SU(2)\nYang-Mills theory.",
        "positive": "Estimating the central charge from the R\u00e9nyi entanglement entropy: We calculate the von Neumann and R\\'enyi bipartite entanglement entropy of\nthe $O(2)$ model with a chemical potential on a 1+1 dimensional Euclidean\nlattice with open and periodic boundary conditions. We show that the\nCalabrese-Cardy conformal field theory predictions for the leading logarithmic\nscaling with the spatial size of these entropies are consistent with a central\ncharge $c=1$. This scaling survives the time continuum limit and truncations of\nthe microscopic degrees of freedom, modifications which allow us to connect the\nLagrangian formulation to quantum Hamiltonians. At half-filling, the forms of\nthe subleading corrections imposed by conformal field theory allow the\ndetermination of the central charge with an accuracy better than two percent\nfor moderately sized lattices. We briefly discuss the possibility of estimating\nthe central charge using quantum simulators."
    },
    {
        "anchor": "Theta Vacua, Confinement and the Continuum Limit: We investigate the dependence of the CP^3 model and of the SU(2) Yang-Mills\ntheory on the vacuum angle theta. The CP^3 model exhibits a first order\ndeconfining phase transition in theta. The critical value of theta runs from pi\nin the strong coupling limit towards zero as beta is taken to infinity.\nQualitatively the same behavior is found in the SU(2) Yang-Mills theory in four\ndimensions. We discuss the renormalization group trajectories. Only the line\nwith theta = 0 allows the cut-off to go to infinity, while the lines with theta\n> 0 end on the line of first order phase transitions. Thus theta is forced to\nzero in the continuum limit.",
        "positive": "The chiral transition as an Anderson transition: At low temperature the low-lying QCD Dirac spectrum obeys random matrix\nstatistics. Recently we found that above $T_{c}$ the lowest part of the\nspectrum consists of localized modes that obey Poisson statistics. An\ninteresting implication of this is that as the system crosses $T_{c}$ from\nabove, the spectral statistics at $\\lambda=0$ changes from Poisson to random\nmatrix. Here we study this transition and its possible implications for the\nfinite temperature transition of QCD-like theories."
    },
    {
        "anchor": "Quantum-Gravity Path-Integrals on Simplicial Lattices: Euclidean quantum-gravity path-integrals are investigated within Regge\ncalculus by computer simulations. The domain of integration is restricted by\nintroducing a lower limit for the fatness of each simplex. We use the standard\nhypercubic triangulation of the 4-torus and irregularly triangulated lattices\nobtained by inserting a small number of vertices using barycentric subdivision.\nFor limited fatness we find an entropy dominated phase with small negative\ncurvature both for the regular and the irregular triangulation.",
        "positive": "A comparison of spectral reconstruction methods applied to non-zero\n  temperature NRQCD meson correlation functions: We present results from the fastsum collaboration's programme to determine\nthe spectrum of the bottomonium system as a function of temperature. Three\ndifferent methods of extracting spectral information are discussed: a Maximum\nLikelihood approach using a Gaussian spectral function for the ground state,\nthe Backus Gilbert method, and the Kernel Ridge Regression machine learning\nprocedure. We employ the fastsum anisotropic lattices with 2+1 dynamical quark\nflavours, with temperatures ranging from 47 to 375 MeV."
    },
    {
        "anchor": "Perfect Abelian dominance of confinement in quark-antiquark potential in\n  SU(3) lattice QCD: In the context of the dual superconductor picture for the confinement\nmechanism, we study maximally Abelian (MA) projection of quark confinement in\nSU(3) quenched lattice QCD with $32^4$ at $\\beta$=6.4 (i.e., $a \\simeq$ 0.058\nfm). We investigate the static quark-antiquark potential $V(r)$, its Abelian\npart $V_{\\rm Abel}(r)$ and its off-diagonal part $V_{\\rm off}(r)$,\nrespectively, from the on-axis lattice data. As a remarkable fact, we find\nalmost perfect Abelian dominance for quark confinement, i.e., $\\sigma_{\\rm\nAbel} \\simeq \\sigma$ for the string tension, on the fine and large-volume\nlattice. We find also a nontrivial summation relation of $V(r) \\simeq V_{\\rm\nAbel}(r) + V_{\\rm off}(r)$.",
        "positive": "Super-Instantons, Perfect Actions, Finite Size Scaling and the Continuum\n  Limit: We discuss some aspects of the continuum limit of some lattice models, in\nparticular the $2D$ $O(N)$ models. The continuum limit is taken either in an\ninfinite volume or in a box whose size is a fixed fraction of the infinite\nvolume correlation length. We point out that in this limit the fluctuations of\nthe lattice variables must be $O(1)$ and thus restore the symmetry which may\nhave been broken by the boundary conditions (b.c.). This is true in particular\nfor the so-called super-instanton b.c. introduced earlier by us. This\nobservation leads to a criterion to assess how close a certain lattice\nsimulation is to the continuum limit and can be applied to uncover the true\nlattice artefacts, present even in the so-called 'perfect actions'. It also\nshows that David's recent claim that super-instanton b.c. require a different\nrenormalization must either be incorrect or an artefact of perturbation theory."
    },
    {
        "anchor": "Spectral properties of the Wilson Dirac operator in the\n  $\u03b5$-regime: We investigate the spectral properties of the Wilson Dirac operator in\nquenched QCD in the microscopic regime. We distinguish the topological sectors\nusing the index as determined by the Wilson flow method. Consequently, the\ndistributions of the low-lying eigenvalues of the Wilson Dirac operator can be\ncompared in each of the topological sectors to predictions from random matrix\ntheory applied to the $\\epsilon$-regime of chiral perturbation theory. We find\nrather good agreement for volumes as small as $(1.5 \\, \\text{fm})^4$ and\nlattice spacings as coarse as $0.1\\, \\text{fm}$, and demonstrate that it is\nindeed possible to extract low-energy constants for Wilson fermions from the\nspectral properties of the Wilson Dirac operator.",
        "positive": "Fluctuations at finite temperature and density: Fluctuations of conserved charges in a grand canonical ensemble can be\ncalculated as derivatives of the free energy with respect to the respective\nchemical potential. They are directly related to experimentally available\nobservables that describe the hadronization in heavy ion collisions. The same\nderivatives can be used to extrapolate zero density results to finite chemical\npotential. We review the recent lattice calculations in the staggered formalism\nand discuss its implications to phenomenology and resummed perturbation theory."
    },
    {
        "anchor": "Chiral invariance and lattice fermions with minimal doubling: A few years ago some attention has been given to a fermionic action on the\nlattice, with a Wilson-like term which is chirally invariant but breaks the\nhypercubic space-time lattice symmetry. This action describes two Dirac fields\nin the continuum limit, provided the coefficient $\\lambda$ of the Wilson-like\nterm satisfies $\\lambda > \\frac{1}{2}$. In this letter it is shown that for\n$\\frac{1}{2} < \\lambda \\leq 1$ the theory is link-reflection positive. The\npropagator has the expected real energy poles. Modulo a phase shift on the\nfermions, the only relevant terms which can be added to the action respecting\nits symmetries have dimension $4$.",
        "positive": "Determination of Karsch Coefficients for 2-colour QCD: We give an update of results from two-colour, two-flavour QCD. Using a Wilson\nfermion action we calculate thermodynamic quantities as a function of chemical\npotential {\\mu}. Calculating the Karsch Coefficients non-perturbatively gives\nus access to the derivative method. Compared to our previously published\nresults, we have improved our analysis leading to revised and more accurate\nestimates for the renormalised energy density, pressure and the trace anomaly."
    },
    {
        "anchor": "Parameters of Heavy Quark Effective Theory from Nf=2 lattice QCD: We report on a non-perturbative determination of the parameters of the\nlattice Heavy Quark Effective Theory (HQET) Lagrangian and of the time\ncomponent of the heavy-light axial-vector current with Nf=2 flavors of massless\ndynamical quarks. The effective theory is considered at the 1/mh order, and the\nheavy mass mh covers a range from slightly above the charm to beyond the beauty\nregion. These HQET parameters are needed to compute, for example, the b-quark\nmass, the heavy-light spectrum and decay constants in the static approximation\nand to order 1/mh in HQET. The determination of the parameters is done\nnon-perturbatively. The computation reported in this paper uses the plaquette\ngauge action and two different static actions for the heavy quark described by\nHQET. For the light-quark action we choose non-perturbatively O(a)-improved\nWilson fermions.",
        "positive": "Exploring the CP-violating Dashen phase in the Schwinger model with\n  tensor networks: We numerically study the phase structure of the two-flavor Schwinger model\nwith matrix product states, focusing on the (1+1)-dimensional analog of the\nCP-violating Dashen phase in QCD. We simulate the two-flavor Schwinger model\naround the point where the positive mass of one fermion flavor corresponds to\nthe negative mass of the other fermion flavor, which is a sign-problem\nafflicted regime for conventional Monte Carlo techniques. Our results indicate\nthat the model undergoes a CP-violating Dashen phase transition at this point,\nwhich manifests itself in abrupt changes of the average electric field and the\nanalog of the pion condensate in the model. Studying the scaling of the\nbipartite entanglement entropy as a function of the volume, we find clear\nindications that this transition is not of first order."
    },
    {
        "anchor": "Probing parity doubling in nucleons at high temperature: The spectrum of nucleons and their parity partners is studied as a function\nof temperature spanning the deconfinement transition. We analyse our results\nusing the correlation functions directly, exponential fits in the hadronic\nphase, and the Maximum Entropy Method. These techniques all indicate that there\nis degeneracy in the parity partners' channels in the deconfined phase. This is\nin accordance with the expectation that there is parity doubling and chiral\nsymmetry in the deconfined phase. In the hadronic phase, we also find that the\nnucleon ground state is largely independent of temperature, whereas there are\nsubstantial temperature effects in the negative parity channel. All results are\nobtained using our FASTSUM 2+1 flavour ensembles.",
        "positive": "Chiral property of domain-wall fermion from eigenvalues of 4D\n  Wilson-Dirac Operator: We investigate a chiral property of the domain-wall fermion (DWF) system\nusing the four-dimensional hermitian Wilson-Dirac operator $H_W$. A formula\nexpressing the Ward-Takahashi identity quark mass $m_{5q}$ with eigenvalues of\nthis operator is derived, which well explains the $N_5$ dependence of $m_{5q}$\nobserved in previous numerical simulations. We further discuss the chiral\nproperty of DWF in the large volume in terms of the spectra of $H_W$."
    },
    {
        "anchor": "Recent Developments in Dual Lattice Algorithms: We review recent progress in numerical simulations with dually transformed\nSU(2) LGT, starting with a discussion of explicit dual amplitudes and\nalgorithms for SU(2) pure Yang Mills in D=3 and D=4. In the D=3 case, we\ndiscuss results that validate the dual algorithm against conventional\nsimulations. We also review how a local, exact dynamical fermion algorithm can\nnaturally be incorporated into the dual framework. We conclude with an outlook\nfor this technique and a look at some of the current challenges we've\nencountered with this method, specifically critical slowing down and the sign\nproblem.",
        "positive": "The $H$ dibaryon from lattice QCD with SU(3) flavor symmetry: We show recent results from the Mainz group using $N_f = 2 + 1$ CLS ensembles\ngenerated at the $SU(3)$ symmetric point. Temporal correlation functions using\ntwo-baryon interpolating operators are calculated with the distillation method.\nIn addition to the spin-0 operators relevant for studying the $H$ dibaryon, we\nadded spin-1 operators to our basis, thereby extending our results to other\nflavor sectors. These preliminary results show a finite-volume energy below the\n$\\Lambda \\Lambda$ threshold. Further calculations are necessary to establish\nwhether the $H$ dibaryon is bound at the physical point."
    },
    {
        "anchor": "Composite operators from the operator product expansion: what can go\n  wrong?: The operator product expansion is used to compute the matrix elements of\ncomposite renormalized operators on the lattice. We study the product of two\nfundamental fields in the two-dimensional sigma-model and discuss the possible\nsources of systematic errors. The key problem turns out to be the violation of\nasymptotic scaling.",
        "positive": "Lattice perturbation theory in the overlap formulation for the Yukawa\n  and gauge interactions: Lattice perturbation theory is discussed in the overlap formulation for the\nYukawa and gauge interactions. One and two point functions are studied for\nfermion, scalar and gauge fields, taking the Standard Model as an example. The\nformulae for the self-energies are given from which their divergent and finite\nparts can be computed at the one loop level."
    },
    {
        "anchor": "Twisted finite-volume corrections to $K_{l3}$ decays with\n  partially-quenched and rooted-staggered quarks: The determination of $|V_{us}|$ from kaon semileptonic decays requires the\nvalue of the form factor $f_+(q^2=0)$ which can be calculated precisely on the\nlattice. We provide the one-loop partially quenched chiral perturbation theory\nexpressions both with and without including the effects of staggered quarks for\nall form factors at finite volume and with partially twisted boundary\nconditions for both the vector current and scalar density matrix elements at\nall $q^2$. We point out that at finite volume there are more form factors than\njust $f_+$ and $f_-$ for the vector current matrix element but that the Ward\nidentity is fully satisfied. The size of the finite-volume corrections at\npresent lattice sizes is small. This will help improve the lattice\ndetermination of $f_+(q^2=0)$ since the finite-volume error is the dominant\nerror source for some calculations. The size of the finite-volume corrections\nmay be estimated on a single lattice ensemble by comparing results for various\ntwist choices.",
        "positive": "QCD thermodynamics with 2+1 flavors at nonzero chemical potential: We present results for the QCD equation of state, quark densities and\nsusceptibilities at nonzero chemical potential, using 2+1 flavor asqtad\nensembles with $N_t=4$. The ensembles lie on a trajectory of constant physics\nfor which $m_{ud}\\approx0.1m_s$. The calculation is performed using the Taylor\nexpansion method with terms up to sixth order in $\\mu/T$."
    },
    {
        "anchor": "Abelian monopole and vortex condensation in lattice gauge theories: We study Abelian monopole and vortex condensation in lattice pure gauge\ntheories. Condensation is detected by means of a disorder parameter defined in\nterms of a gauge-invariant effective action introduced using the lattice\nSchr\\\"odinger functional. Dirac monopoles condense in the confined phase of\nU(1) lattice gauge theory. Abelian monopoles and Abelian vortices condense in\nthe confined phase of SU(2) and SU(3) lattice gauge theories.",
        "positive": "B-->pi and B-->K transitions in standard and quenched chiral\n  perturbation theory: We study the effects of chiral logs on the heavy-->light pseudoscalar meson\ntransition form factors by using standard and quenched chiral perturbation\ntheory combined with the static heavy quark limit. The resulting expressions\nare used to indicate the size of uncertainties due to the use of the quenched\napproximation in the current lattice studies. They may also be used to assess\nthe size of systematic uncertainties induced by missing chiral log terms in\nextrapolating toward the physical pion mass. We also provide the coefficient\nmultiplying the quenched chiral log, which may be useful if the quenched\nlattice studies are performed with very light mesons."
    },
    {
        "anchor": "Instanton liquid properties from lattice QCD: We examined the instanton contribution to the QCD configurations generated\nfrom lattice QCD for $N_F=0$, $N_F=2+1$ and $N_F=2+1+1$ dynamical quark flavors\nfrom two different and complementary approaches. First via the use of Gradient\nflow, we computed instanton liquid properties using an algorithm to localize\ninstantons in the gauge field configurations and studied their evolution with\nflow time. Then, the analysis of the running at low momenta of gluon Green's\nfunctions serves as an independent confirmation of the instanton density which\ncan also be derived without the use of the Gradient flow.",
        "positive": "Fate of the Critical Line and Chiral Transition in Finite-Temperature\n  Lattice QCD with the Wilson Quark Action: Finite-temperature phase structure of lattice QCD with the Wilson quark\naction is analyzed. We show that the critical line at finite temperatures,\ndefined to be the line of vanishing pion screening mass, turns back toward\nstrong coupling, forming a cusp on the $(\\beta, K)$ plane, and that the line of\nthermal transition runs past the tip of the cusp without touching the critical\nline. Previous results are discussed in the light of our findings."
    },
    {
        "anchor": "A study of center vortices in SU(2) and SU(3) gauge theories: We show how center vortices and Abelian monopoles both appear as local gauge\nambiguities in the Laplacian Center gauge. Numerical results, for SU(2) and\nSU(3), support the view that the string tension obtained in the\ncenter-projected theory matches the full string tension when the continuum\nlimit is taken.",
        "positive": "First order phase transition of the q-state Potts model in two\n  dimensions: We have calculated the large-$q$ series of the energy cumulants, the\nmagnetization cumulants and the correlation length at the first order phase\ntransition point both in the ordered and disordered phases for the $q$-state\nPotts model in two dimensions. The series enables us to estimate the numerical\nvalues of the quantities more precisely by a factor of $10^2 - 10^4$ than the\nMonte Carlo simulations. From the large-$q$ series of the eigenvalues of the\ntransfer matrix, we also find that the excited states form a continuum spectrum\nand there is no particle state at the first order phase transition point."
    },
    {
        "anchor": "Update on $SU(2)$ with one adjoint Dirac flavor: We present an update of our ongoing study of the SU(2) gauge theory with one\nflavor of Dirac fermion in the adjoint representation. Compared to our previous\nresults we now have data at larger lattice volumes, smaller values of the\nfermion mass, and also larger values of $\\beta$. We present data for the\nspectrum of mesons, baryons, glueballs, and the hybrid fermion-glue state, as\nwell as new estimates of the mass anomalous dimension from both finite-size\nhyperscaling and the Dirac mode number, and discuss the implications of these\ndata for the presence or otherwise of chiral symmetry breaking in this theory.",
        "positive": "Digitizing SU(2) Gauge Fields and What to Look Out for When Doing So: With the long term perspective of using quantum computers and tensor networks\nfor lattice gauge theory simulations, an efficient method of digitizing gauge\ngroup elements is needed. We thus present our results for a handful of\ndiscretization approaches for the non-trivial example of SU(2), such as its\nfinite subgroups, as well as different classes of finite subsets. We focus our\nattention on a freezing transition observed towards weak couplings. A\ngeneralized version of the Fibonacci spiral appears to be particularly\nefficient and close to optimal."
    },
    {
        "anchor": "Spectrum of SU(2) gauge theory at large number of flavors: We present a numerical study of the spectrum of an asymptotically non-free\n$SU(2)$ gauge theory with $N_f=24$ massive fermion flavors. For such large\nnumber of flavors, asymptotic freedom is lost and the massless theory is\ngoverned by a gaussian fixed point at long distances. If fermions are massive\nthey decouple at low energy scales and the theory is confining. We present a\nscaling law for the masses of the hadrons, glueballs and string tension as\nfunctions of fermion mass. The hadrons become effectively heavy quark systems,\nwith masses approximately twice the fermion mass, whereas the energy scale of\nthe confinement, probed by e.g. the string tension, is much smaller and\nvanishes asymptotically as $m_\\text{fermion}^{2.18}$. Our results from lattice\nsimulations are compatible with this behaviour.",
        "positive": "Finite Volume for Three-Flavour Partially Quenched Chiral Perturbation\n  Theory through NNLO in the Meson Sector: We present a calculation of the finite volume corrections to meson masses and\ndecay constants in three flavour Partially Quenched Chiral Perturbation Theory\n(PQChPT) through two-loop order in the chiral expansion for the flavour-charged\n(or off-diagonal) pseudoscalar mesons. The analytical results are obtained for\nthree sea quark flavours with one, two or three different masses. We reproduce\nthe known infinite volume results and the finite volume results in the\nunquenched case. The calculation has been performed using the supersymmetric\nformulation of PQChPT as well as with a quark-flow technique.\n  Partial analytical results can be found in the appendices. Some examples of\ncases relevant to lattice QCD are studied numerically. Numerical programs for\nall results are available as part of the CHIRON package."
    },
    {
        "anchor": "A gauge-invariant object in non-Abelian gauge theory: We propose a nonlocal definition of a gauge-invariant object in terms of the\nWilson loop operator in a non--Abelian gauge theory. The trajectory is a closed\ncurve defined by an (untraced) Wilson loop which takes its value in the center\nof the color group. We show that definition shares basic features with the\ngauge-dependent 't Hooft construction of Abelian monopoles in Yang-Mills\ntheories. The chromoelectric components of the gluon field have a hedgehog-like\nbehavior in the vicinity of the object. This feature is dual to the structure\nof the 't Hooft-Polyakov monopoles which possesses a hedgehog in the magnetic\nsector. A relation to color confinement and lattice implementation of the\nproposed construction are discussed.",
        "positive": "Fermion induced SU$(N)$ Yang-Mills Theory: We investigate the gauge interaction induced by heavy fermions using both\ndimensional and lattice regularization. We study the condition under which\nheavy fermions induce a continuum gauge theory."
    },
    {
        "anchor": "Neutral meson mixing in the $B^0_{(s)}$ sector from lattice QCD: We summarise the current status of lattice QCD computations of neutral meson\nparameters in the $B_d^0$ and the $B_s^0$ systems. We comment on recent results\nand anticipate further improvements on the uncertainties in the future.",
        "positive": "The Finite Temperature Phase Transition in the Lattice SU(2)-Higgs Model: We study the finite temperature transition of SU(2)-Higgs model with lattice\nMonte Carlo techniques. We use dimensional reduction to transform the original\n4-dimensional SU(2)-gauge + fundamental Higgs theory to an effective\n3-dimensional SU(2) + adjoint Higgs + fundamental Higgs model. The simulations\nwere performed with Higgs masses of 35 and 80 GeV; in both cases we observe a\nstronger first order transition than the perturbation theory predicts,\nindicating that the dynamics of the transition strongly depend on\nnon-perturbative effects."
    },
    {
        "anchor": "Fresh look on triality: Investigating the $Z_3$ symmetry in Quantum Chromodynamics (QCD) we show that\nfull QCD with a vacuum of vanishing baryonic number does not lead to metastable\nphases. Rather in QCD with dynamical fermions, the degeneracy of $Z_3$ phases\nmanifests itself in observables without open triality.",
        "positive": "Computation of disconnected contributions to nucleon observables: We compare several methods for computing disconnected fermion loops\ncontributing to nucleon three-point functions. The comparison is carried out\nusing one ensemble of $N_f=2+1+1$ twisted mass fermions with pion mass of 373\nMeV. The complete set of operators up to one-derivative are examined by\ndeveloping optimized code for mutli-GPUs. Simple guidelines are given as to the\npreferable method for each class of operators."
    },
    {
        "anchor": "Delta S=2 and Delta I=3/2 Matrix Elements in Quenched QCD: We present preliminary results for B_K, B_7^{3/2} and B_8^{3/2} from two\nhigh-statistics lattice computations. These calculations are performed at\nbeta=6.0 and 6.2 in the quenched approximation, using mean-field-improved\nSheikholeslami-Wohlert fermionic actions.",
        "positive": "Latest results from lattice N=4 supersymmetric Yang--Mills: We present some of the latest results from our numerical investigations of\nN=4 supersymmetric Yang--Mills theory formulated on a space-time lattice. Based\non a construction that exactly preserves a single supersymmetry at non-zero\nlattice spacing, we recently developed an improved lattice action that is now\nbeing employed in large-scale calculations. Here we update our studies of the\nstatic potential using this new action, also applying tree-level lattice\nperturbation theory to improve the analysis of the potential itself.\nConsidering relatively weak couplings, we obtain results for the Coulomb\ncoefficient that are consistent with continuum perturbation theory."
    },
    {
        "anchor": "Pade-Borel approximation of the continuum limit of strong coupling\n  lattice fields: Two dimensional non-linear O(N) sigma model at N>=3: Based on the strong coupling expansion, we reinvestigate two dimensional O(N)\nsigma model by the use of Pade-Borel approximants. The conventional strong\ncoupling expansion of the mass square M in momentum space in beta=1/g^2 is\ninverted to give beta expanded in 1/M. Borel transform of beta with respect to\nM is carried out and the result is improved as the rational function by Pade\nmethod. We find the behavior of Pade-Borel transformed bare coupling at 18th\norder is consistent for N>=3 with that of continuum scaling to the four-loop\nperturbation theory. We estimate non-perturbative mass gap at N>=3 and find the\nagreement with the exact result by Hasenfratz et.al.",
        "positive": "QCD with light Wilson quarks on fine lattices (II): DD-HMC simulations\n  and data analysis: In this second report on our recent numerical simulations of two-flavour QCD,\nwe provide further technical details on the simulations and describe the\nmethods we used to extract the meson masses and decay constants from the\ngenerated ensembles of gauge fields. Among the topics covered are the choice of\nthe DD-HMC parameters, the issue of stability, autocorrelations and the\nstatistical error analysis. Extensive data tables are included as well as a\nshort discussion of the quark-mass dependence in partially quenched QCD,\nsupplementing the physics analysis that was presented in the first paper in\nthis series."
    },
    {
        "anchor": "Phase Structure of Four-dimensional Simplicial Quantum Gravity with a\n  U(1) Gauge Field: The phase structure of four-dimensional simplicial quantum gravity coupled to\nU(1) gauge fields has been studied using Monte-Carlo simulations. The smooth\nphase is found in the intermediate region between the crumpled phase and the\nbranched polymer phase. This new phase has a negative string susceptibility\nexponent, even if the number of vector fields (Nv) is 1. The phase transition\nbetween the crumpled phase and the smooth phase has been studied by a finite\nsize scaling method. From the numerical results, we expect that this model\n(coupled to one gauge field) has a higher order phase transition than first\norder, which means the possibility to take the continuum limit at the critical\npoint. Furthermore, we consider a modification of the balls-in-boxes model for\na clear understanding of the relation between the numerical results and the\nanalytical one.",
        "positive": "Parallel tempering and decorrelation of topological charge in full QCD: The improvement of simulations of QCD with dynamical Wilson fermions by\ncombining the Hybrid Monte Carlo algorithm with parallel tempering is studied\non $10^4$ and $12^4$ lattices. As an indicator for decorrelation the\ntopological charge is used."
    },
    {
        "anchor": "Anisotropic Improved Actions: The studies of the quantum corrections for the anisotropy\nparameter,$\\eta(=\\xi_R/\\xi_B)$, for the improved actions, $\\beta (C_0\nL({Plaq.}) + C_1 L({Rect.}))$, are proceeded in the medium to strong coupling\nregion on anisotropic lattices. The global features for the $\\eta$ parameters\nas a function of $\\beta$ and the coefficient $C_{1}$ have been clarified. It\nhas been found by the perturbative analysis that as $C_1$ decreases, the slope\nof the $\\eta(\\beta)$ becomes less steep and for the actions whose $C_{1}$ is\nless than -0.160, $\\eta$ decreases as $\\beta$ decreases, contrary to the case\nof the standard action. In the medium to strong coupling region, the $\\eta$\nparameter begins to increase as $\\beta$ decreases for all $C_{1}$. This means\nthat for the actions with $C_{1} < -0.160$, the one-loop perturbative results\nfor $\\eta$ break down qualitatively and the $\\eta$ parameters have a dip. As a\nresult of this dip structure the $\\eta$ for Iwasaki's action remains close to\nunity in the wide range of $\\beta$.",
        "positive": "The $B^*B\u03c0$ coupling with relativistic heavy quarks: We report on a calculation of the $B^*B\\pi$ coupling in lattice QCD. The\nstrong matrix element $\\langle B \\pi | B^*\\rangle$ is directly related to the\nleading order low-energy constant in heavy meson chiral perturbation theory\n(HM$\\chi$PT) for $B$-mesons. We carry out our calculation directly at the\n$b$-quark mass using a non-perturbatively tuned clover action that controls\ndiscretisation effects of order $|\\vec{p}a|$ and $(ma)^n$ for all $n$. Our\nanalysis is performed on RBC/UKQCD gauge configurations using domain wall\nfermions and the Iwasaki gauge action at two lattice spacings of\n$a^{-1}=1.73(3)$ GeV, $a^{-1}=2.28(3)$ GeV, and unitary pion masses down to 290\nMeV. We achieve good statistical precision and control all systematic\nuncertainties, giving a final result for the HM$\\chi$PT coupling $g_b =\n0.569(48)_{stat}(59)_{sys}$ in the continuum and at the physical light-quark\nmasses. This is the first calculation performed directly at the physical\n$b$-quark mass and lies in the region one would expect from carrying out an\ninterpolation between previous results at the charm mass and at the static\npoint."
    },
    {
        "anchor": "Heavy quark masses from lattice QCD: I outline the basic strategies for the computation of charm and bottom quark\nmasses by means of lattice QCD, where particular emphasis is placed on the\nnon-perturbative renormalization of the effective theory for the b-quark in\nheavy-light systems. A few selected results in the quenched approximation are\nreviewed, and the current status of extending these calculations to QCD with\ndynamical quarks is summarized.",
        "positive": "Large volumes and spectroscopy of walking theories: A detailed investigation of finite size effects is performed for SU(2) gauge\ntheory with two fermions in the adjoint representation, which previous lattice\nstudies have shown to be inside the conformal window. The system is\ninvestigated with different spatial and temporal boundary conditions on\nlattices of various spatial and temporal extensions, for two values of the bare\nfermion mass representing a {\\em heavy} and {\\em light} fermion regime. Our\nstudy shows that the infinite volume limit of masses and decay constants in the\nmesonic sector is reached only when the mass of the pseudoscalar particle\n$M_\\mathrm{PS}$ and the spatial lattice size $L$ satisfy the relation $L\nM_\\mathrm{PS} \\ge 15$. This bound, which is at least a factor of three higher\nthan what observed in QCD, is a likely consequence of the different spectral\nsignatures of the two theories, with the scalar isosinglet ($0^{++}$ glueball)\nbeing the lightest particle in our model. In addition to stressing the\nimportance of simulating large lattice sizes, our analysis emphasises the need\nto understand quantitatively the {\\em full} spectrum of the theory rather than\njust the spectrum in the mesonic isotriplet sector. While for the lightest\nfermion measuring masses from gluonic operators proves to be still challenging,\nreliable results for glueball states are obtained at the largest fermion mass\nand, in the mesonic sector, for both fermion masses. As a byproduct of our\ninvestigation, we perform a finite size scaling of the pseudoscalar mass and\ndecay constant. The data presented in this work support the conformal behaviour\nof this theory with an anomalous dimension $\\gamma_* \\simeq 0.37$."
    },
    {
        "anchor": "Thermodynamics of two-colour QCD: We discuss the thermodynamics of two-colour QCD with four flavours of\nstaggered quarks on 8^3x4 and 16^3x4 lattices. In our simulations we use the\nNaik action for the fermions and a (1,2) tree-level improved gauge action. We\nanalyze the deconfinement and chiral phase transitions for four different quark\nmasses (m=0.1,0.05,0.025,0.015). Contrary to three-colour QCD the peak in the\nPolyakov loop susceptibility decreases with decreasing quark mass. This\nreflects an early breaking of the string in the heavy quark potential, which we\nverify explicitly by calculating the heavy quark potential at finite\ntemperature using Polyakov loop correlations.",
        "positive": "B-meson decay constants with domain-wall light quarks and\n  nonperturbatively tuned relativistic b-quarks: We report on our progress to obtain the decay constants f_B and f_Bs from\nlattice-QCD simulations on the RBC-UKQCD Collaborations 2+1 flavor domain-wall\nIwasaki lattices. Using domain-wall light quarks and relativistic b-quarks we\nanalyze data with several partially quenched light-quark masses at two lattice\nspacings of a approx 0.11 fm and a approx 0.08 fm."
    },
    {
        "anchor": "Monopoles and hybrids in Abelian projection of lattice QCD: We study topological defects constructed from diagonal and non-diagonal\ngluons in Abelian projection of zero temperature lattice QCD. We compare\nresults obtained in the quenched and non-quenched vacuum field configurations\nand show that the density of hybrids is higher than the density of monopoles.\nThe density of some hybrids is sensitive to the presence of the virtual\nfermions.",
        "positive": "Lattice QCD thermodynamic results with improved staggered fermions: We present results on the QCD equation of state, obtained with two different\nimproved dynamical staggered fermion actions and almost physical quark masses.\nLattice cut-off effect are discussed in detail as results for three different\nlattice spacings are available now, i.e. results have been obtained on lattices\nwith temporal extent of $N_\\tau=4,6$ and 8. Furthermore we discuss the Taylor\nexpansion approach to non-zero baryon chemical potential and present the\nisentropic equation of state on lines of constant entropy per baryon number."
    },
    {
        "anchor": "Topology of dynamical lattice configurations including results from\n  dynamical overlap fermions: We investigate how the topological charge density in lattice QCD simulations\nis affected by violations of chiral symmetry in different fermion actions. To\nthis end we compare lattice configurations generated with a number of different\nactions including first configurations generated with exact overlap quarks. We\nvisualize the topological profiles after mild smearing. In the topological\ncharge correlator we measure the size of the positive core, which is known to\nvanish in the continuum limit. To leading order we find the core size to scale\nlinearly with the lattice spacing with the same coefficient for all actions,\neven including quenched simulations. In the subleading term the different\nactions vary over a range of about 10 %. Our findings suggest that non-chiral\nlattice actions at current lattice spacings do not differ much for this\nspecific observable related to topology, both among themselves and compared to\noverlap fermions.",
        "positive": "Split of the pseudo-critical temperatures of chiral and\n  confine/deconfine transitions by temperature gradient: Searching of the critical endpoint of the phase transition of Quantum\nChromodynamics~(QCD) matter in experiments is of great interest. The\ntemperature in the fireball of a collider is location dependent, however, most\ntheoretical studies address the scenario of uniform temperature. In this work,\nthe effect of temperature gradients is investigated using lattice QCD approach.\nWe find that the temperature gradient catalyzes chiral symmetry breaking,\nmeanwhile the temperature gradient increases the Polyakov loop in the confined\nphase but suppresses the Polyakov loop in the deconfined phase. Furthermore,\nthe temperature gradient decreases the pseudo-critical temperature of chiral\ntransition but increases the pseudo-critical temperature of the\nconfine/deconfine transition."
    },
    {
        "anchor": "Lattice chiral gauge theories through gauge fixing: After an introduction in which we review the fundamental difficulty in\nconstructing lattice chiral gauge theories, we discuss the analytic and\nnumerical evidence that abelian lattice chiral gauge theories can be\nnon-perturbatively constructed through the gauge-fixing approach. While a\ncomplete non-abelian extension is still under construction, we also show how\nfermion-number violating processes are realized in this approach.",
        "positive": "Constituent monopoles without gauge fixing: We discuss the recent construction of new exact finite temperature instanton\nsolutions with a non-trivial value of the Polyakov loop at infinity. They can\nbe shown, in a precise and gauge invariant way, to be formed by the\nsuperposition of n BPS monopoles for an SU(n) gauge group."
    },
    {
        "anchor": "Instanton and Monopole in External Chromomagnetic Fields: We study properties of instanton and monopole in an external chromomagnetic\nfield. Generally, the 't Hooft ansatz is no longer a solution of the Yang-Mills\nfield equation in the presence of external fields. Therefore, we investigate a\nstabilized instanton solution with minimal total Yang-Mills action in a\nnontrivial topological sector. With this aim, we consider numerical\nminimization of the action with respect to the global color orientation, the\nanisotropic scale transformation and the local gauge-like transformation\nstarting from a simple superposed gauge field of the 't Hooft ansatz and the\nexternal color field. Here, the external color field is, for simplicity, chosen\nto be a constant Abelian magnetic field along a certain direction. Then, the\n4-dimensional rotational symmetry O(4) of the instanton solution is reduced to\ntwo 2-dimensional rotational symmetries $O(2)\\times O(2)$ due to the effect of\na homogeneous external field. In the space $\\mib{R}^{3}$ at fixed $t$, we find\na quadrupole deformation of this instanton solution. In the presence of a\nmagnetic field $\\vec{H}$, a prolate deformation occurs along the direction of\n$\\vec{H}$. Contrastingly, in the presence of an electric field $\\vec{E}$ an\noblate deformation occurs along the direction of $\\vec{E}$. We further discuss\nthe local correlation between the instanton and the monopole in the external\nfield in the maximally Abelian gauge. The external field affects the appearance\nof the monopole trajectory around the instanton. In fact, a monopole and\nanti-monopole pair appears around the instanton center, and this monopole loop\nseems to partially screen the external field.",
        "positive": "Color confinement and dual superconductivity in full QCD: We report on evidence that confinement is related to dual superconductivity\nof the vacuum in full QCD, as in quenched QCD. The vacuum is a dual\nsuperconductor in the confining phase, whilst the U(1) magnetic symmetry is\nrealized a la Wigner in the deconfined phase."
    },
    {
        "anchor": "Full Spectrum of Lyapunov Exponents in Gauge Field Theory: We analyze the Lyapunov exponents of U(1) gauge fields across the phase\ntransition from the confinement to the Coulomb phase on the lattice which are\ninitialized by quantum Monte Carlo simulations. We observe all features of a\nstrange attractor with a tendency to regularity towards the continuum limit.\nResults are also displayed for the full spectrum of Lyapunov exponents of the\nSU(2) gauge system.",
        "positive": "Phases of planar QCD on the torus: At infinite N, continuum Euclidean SU(N) gauge theory defined on a\nsymmetrical four torus has a rich phase structure with phases where the finite\nvolume system behaves as if it had infinite extent in some or all of the\ndirections. In addition, fermions are automatically quenched, so planar QCD\nshould be cheaper to solve numerically that full QCD. Large N is a relatively\nunexplored and worthwhile direction of research in lattice field theory."
    },
    {
        "anchor": "Visualization of topological objects in QCD: Recently evidence appeared that instantons and monopoles have a certain local\ncorrelation in four-dimensional pure $SU(2)$ and $SU(3)$ gauge theory. We\nvisualize several specific gauge field configurations and show directly that\nthere is an enhanced probability for finding maximally projected abelian\nmonopole loops in the vicinity of instantons. This feature is independent of\nthe topological charge definition used.",
        "positive": "A Note on the Possible Existence of an Instanton-like Self-Dual Solution\n  to Lattice Euclidean Gravity: The self-dual solution to lattice Euclidean gravity is constructed. In\ncontrast to the well known Eguchi-Hanson solution to continuous Euclidean\nGravity, the lattice solution is asymptotically {\\it{globally}} Euclidean,\ni.e., the boundary of the space as $r\\longrightarrow\\infty$ is $S^3=SU(2)$."
    },
    {
        "anchor": "Quantum tunneling in the real-time path integral by the Lefschetz\n  thimble method: Quantum tunneling is mostly discussed in the Euclidean path integral\nformalism using instantons. On the other hand, it is difficult to understand\nquantum tunneling based on the real-time path integral due to its oscillatory\nnature, which causes the notorious sign problem. We show that recent\ndevelopment of the Lefschetz thimble method enables us to investigate this\nissue numerically. In particular, we find that quantum tunneling occurs due to\ncomplex trajectories, which are actually observable experimentally by using the\nso-called weak measurement.",
        "positive": "RG scaling relations at chiral phase transition in two-flavor QCD: We investigate the nature of the chiral phase transition in the massless\ntwo-flavor QCD using the renormalization group improved gauge action and the\nWilson quark action on $32^3\\times 16$, $24^3\\times 12$, and $16^3\\times 8$\nlattices. Based on the renormalization group equation, we derive the scaling\nrelation for the effective masses of mesons at the chiral phase transition\npoint. If the chiral phase transition is second order, the effective masses as\na function of the rescaled time/space do not depend on the lattice size and\nshow the universal behavior. We find that our numerical simulations on the\nthree sizes of lattices are excellently on the scaling curves, which is\nconsistent with the second order phase transition."
    },
    {
        "anchor": "Rare Kaon Decays on the Lattice: We show that long distance contributions to the rare decays K -> pi nu nu-bar\nand K -> pi l+ l- can be computed using lattice QCD. The proposed approach\nrequires well established methods, successfully applied in the calculations of\nelectromagnetic and semileptonic form factors. The extra power divergences,\nrelated to the use of weak four-fermion operators, can be eliminated using only\nthe symmetries of the lattice action without ambiguities or complicated\nnon-perturbative subtractions. We demonstrate that this is true even when a\nlattice action with explicit chiral symmetry breaking is employed. Our study\nopens the possibility of reducing the present uncertainty in the theoretical\npredictions for these decays.",
        "positive": "Chiral condensate, quark charge and chiral density: We study the topological and fermionic vacuum structure of four-dimensional\nQCD on the lattice by means of correlators of fermionic observables and\ntopological densities. We show the existence of strong local correlations\nbetween the topological charge density and the quark condensate, charge and\nchiral density. By analysis of individual gauge configurations, we visualize\nthat instantons (antiinstantons) carry positive (negative) chirality, whereas\nthe quark charge density fluctuates in sign within instantons."
    },
    {
        "anchor": "Lowest Order Hadronic Contribution to the Muon g-2: We present the most recent lattice results for the lowest-order hadronic\ncontribution to the muon anomalous magnetic moment using 2+1 flavor improved\nstaggered fermions. A precise fit to the low-q^2 region of the vacuum\npolarization is necessary to accurately extract the muon g-2. To obtain this\nfit, we use staggered chiral perturbation theory with the inclusion of the\nvector particles as resonances, to evaluate the vacuum polarization. We discuss\nthe preliminary fit results and attendant systematic uncertainties, paying\nparticular attention to the relative contributions of the pions and vector\nmesons.",
        "positive": "The density of states from first principles: We present a novel algorithm to compute the density of states, which is\nproven to converge to the correct result. The algorithm is very general and can\nbe applied to a wide range of models, in the frameworks of Statistical\nMechanics and Lattice Gauge Theory. All the thermal or quantum expectation\nvalues can then be obtained by a simple integration of the density of states.\nAs an application, a numerical study of 4d U(1) compact lattice gauge theory is\npresented."
    },
    {
        "anchor": "The Twisted Gradient Flow strong coupling with Parallel Tempering on\n  Boundary Conditions: We present a proposal for calculating the running of the coupling constant of\nthe $\\mathrm{SU}(3)$ pure-gauge theory, which combines the Twisted Gradient\nFlow (TGF) renormalization scheme with Parallel Tempering on Boundary\nConditions (PTBC). The TGF is a gradient flow-based renormalization scheme\nformulated in an asymmetric lattice with twisted boundary conditions. Combined\nwith step scaling, it has been successfully used to calculate the\n$\\mathrm{SU}(3)$ $\\Lambda$ parameter. As with all gradient flow-based schemes,\nthe coupling constant is highly correlated with the topological charge and\naffected by topology freezing, an issue addressed by projecting the\ndetermination of the coupling onto the zero topological sector. As an\nalternative to the zero-charge projection, we combine TGF with PTBC, by\nreplicating multiple copies of the same lattice, interpolating between periodic\nand open boundary conditions in a parallel-tempered manner. We present a first\nexploration of these ideas by analyzing specific ensembles of $\\mathrm{SU}(3)$\nlattices with and without PTBC.",
        "positive": "Prediction of the bottomonium D-wave spectrum from full lattice QCD: We calculate the full spectrum of D-wave states in the Upsilon system in\nlattice QCD for the first time, using an improved version of NonRelativistic\nQCD on coarse and fine \"second generation\" gluon field configurations from the\nMILC collaboration that include the effect of up, down, strange and charm\nquarks in the sea. Taking the 2S-1S splitting to set the lattice spacing, we\ndetermine the ^3D_2 - 1S splitting to 2.3%, and find agreement with experiment.\nOur prediction of the fine structure relative to the ^3D_2 gives the ^3D_3 at\n10.181(5) GeV and the ^3D_1 at 10.147(6) GeV. We also discuss the overlap of\n^3D_1 operators with ^3S_1 states."
    },
    {
        "anchor": "Slope of the beta function at the fixed point of SU(2) gauge theory with\n  six or eight flavors: We consider measurement of the leading irrelevant scaling exponent\n$\\gamma_g^\\ast$, given by the slope of the beta function, at the fixed point of\nSU(2) gauge theory with six or eight flavors. We use the running coupling\nmeasured using the gradient flow method and perform the continuum extrapolation\nby interpolating the measured beta function. We study also the dependence of\nthe results on different discretization of the flow. For the eight flavor\ntheory we find $\\gamma_g^\\ast=0.19(8)_{-0.09}^{+0.21}$. Applying the same\nanalysis also for the six flavor theory, we find\n$\\gamma_g^\\ast=0.648(97)_{-0.1}^{+0.16}$ consistently with the earlier\nanalysis.",
        "positive": "Quark contribution to the proton spin from 2+1+1-flavor lattice QCD: We present the first chiral-continuum extrapolated up, down and strange quark\nspin contribution to the proton spin using lattice QCD. For the connected\ncontributions, we use eleven ensembles of 2+1+1-flavor of Highly Improved\nStaggered Quarks (HISQ) generated by the MILC Collaboration. They cover four\nlattice spacings $a \\approx \\{0.15,0.12,0.09,0.06\\}$ fm and three pion masses,\n$M_\\pi \\approx \\{315,220,135\\}$ MeV, of which two are at the physical pion\nmass. The disconnected strange calculations are done on seven of these\nensembles, covering the four lattice spacings but only one with the physical\npion mass. The disconnected light quark calculation was done on six ensembles\nat two values of $M_\\pi \\approx \\{315,220\\}$ MeV. High-statistics estimates on\neach ensemble for all three quantities allow us to quantify systematic\nuncertainties and perform a simultaneous chiral-continuum extrapolation in the\nlattice spacing and the light-quark mass. Our final results are $\\Delta u\n\\equiv \\langle 1 \\rangle_{\\Delta u^+} = 0.777(25)(30)$, $\\Delta d \\equiv\n\\langle 1 \\rangle_{\\Delta d^+} = -0.438(18)(30)$, and $\\Delta s \\equiv \\langle\n1 \\rangle_{\\Delta s^+} = -0.053(8)$, adding up to a total quark contribution to\nproton spin of $\\sum_{q=u,d,s} (\\frac{1}{2} \\Delta q) = 0.143(31)(36)$. The\nsecond error is the systematic uncertainty associated with the chiral-continuum\nextrapolation. These results are obtained without model assumptions and are in\ngood agreement with the recent COMPASS analysis $0.13 < \\frac{1}{2} \\Delta\n\\Sigma < 0.18$, and with the $\\Delta q$ obtained from various global analyses\nof polarized beam or target data."
    },
    {
        "anchor": "The role of heavy fermions: Heavy dynamical fermions with masses around the cut-off do not change the low\nenergy physics apart from a finite renormalization of the gauge coupling. In\nthis paper we study how light the heavy fermions have to be to cause more than\nthis trivial renormalization.",
        "positive": "Parton physics from a heavy-quark operator product expansion: Formalism\n  and Wilson coefficients: Parton distribution functions (PDFs) and light-cone distribution amplitudes\n(LCDAs) are central non-perturbative objects of interest in high-energy\ninelastic and elastic scattering, respectively. As a result, an ab-initio\ndetermination of these objects is highly desirable. In this paper we present\ntheoretical details for the calculation of the PDFs and LCDAs using a\nheavy-quark operator product expansion method. This strategy was proposed in a\nprevious paper [Phys. Rev. D 73, 014501 (2006)] for computing higher moments of\nthe PDFs using lattice QCD. Its central feature is the introduction of a\nfictitious, valence heavy quark. In the current article, we show that the\noperator product expansion (OPE) of the hadronic matrix element we study can\nalso be expressed as the convolution of a perturbative matching kernel and the\ncorresponding light-cone distribution, which in principle can be inverted to\ndetermine the parton momentum fraction dependence. Regarding the extraction of\nhigher moments, this work also provides the one-loop Wilson coefficients in the\nOPE formulas for the unpolarized PDF, helicity PDF and pseudo-scalar meson\nLCDAs. Although these Wilson coefficients for the PDFs can be inferred from\nexisting results in the literature, those for the LCDAs are new."
    },
    {
        "anchor": "S and P-wave heavy-light mesons in lattice NRQCD: The mass spectrum of S and P-wave mesons containing a single heavy quark is\ncomputed in the quenched approximation, using NRQCD up to third order in the\ninverse heavy quark mass expansion. Previous results found third order\ncontributions which are as large in magnitude as the total second order\ncontribution for the charmed S-wave spin splitting. The present work considers\nvariations such as anisotropic lattices, Landau link tadpole improvement, and a\nhighly-improved light quark action, and finds that the second order correction\nto the charmed S-wave spin splitting is about 20% of the leading order\ncontribution, while the third order correction is about 20%(10%) for\nD^*-D(D_s^*-D_s). Nonleading corrections are very small for the bottom meson\nspectrum, and are statistically insignificant for the P-wave charmed masses.\nThe relative orderings among P-wave charmed and bottom mesons, and the sizes of\nthe mass splittings, are discussed in light of experimental data and existing\ncalculations.",
        "positive": "Model A Dynamics and the Deconfining Phase Transition for Pure Lattice\n  Gauge Theory: We consider model A dynamics for a heating quench from the disordered\n(confined) into the ordered (deconfined) phase of SU(3) lattice gauge theory.\nFor $4 N_{\\sigma}^3$ lattices the exponential growth factors of low-lying\nstructure function modes are calculated. The linear theory of spinodal\ndecompositions is compared with the data from an effective model and the Debye\nscreening mass is estimated from the critical mode. Further, the quench leads\nto competing vacuum domains, which make the equilibration of the QCD vacuum\nafter the heating non-trivial. We investigate the influence of such domains on\nthe gluonic energy density."
    },
    {
        "anchor": "Geometrical Interpretation of the KPZ Exponents: We provide evidence that the KPZ exponents in two-dimensional quantum gravity\ncan be interpreted as scaling exponents of correlation functions which are\nfunctions of the invariant geodesic distance between the fields.",
        "positive": "Monopole condensation ans superconductivity: the $SU(2)$ case: We study the behaviour of a suitably defined disorder parameter, showing for\nthe first time monopole condenssation in the ground state of QCD."
    },
    {
        "anchor": "QCD phase diagram for finite imaginary chemical potential with HISQ\n  fermions: We present results from an ongoing study of the phase diagram of (2+1)-flavor\nQCD using the HISQ action with smaller than physical light quark masses in the\nRoberge-Weiss (RW) plane on lattices with temporal extent $N_\\tau=4$. We find\nthat the endpoint of the $1^{st}$ order RW transition line remains $2^{nd}$\norder at least down to light quark masses corresponding to Goldstone pion\nmasses of $55$ MeV. Furthermore, we show that the chiral condensate is\nsensitive to the RW transition and may serve as a energy-like operator\ncharacterizing universal behavior close to the RW endpoint.",
        "positive": "Precise Determination of the Charm Quark Mass: The determination of the charm quark mass is now possible to 1% from QCD,\nwith lattice QCD pushing the error down below 1%. I will describe the\ningredients of this approach and how it can achieve this accuracy. Results for\nquark mass ratios, m_c/m_s and m_b/m_c, can also be determined to 1% from\nlattice QCD, allowing accuracy for the heavy quark masses to be leveraged into\nthe light quark sector. I will discuss the prospects for, and importance of,\nimproving results in future calculations."
    },
    {
        "anchor": "Theoretical strategies for epsilon'/epsilon: We review the current status of calculations of the two pion decays of the\nkaon using the first-principles methods of lattice gauge theory and the\nsignificant challenges that these calculations pose. While a calculation with\ncontrolled errors at even the 10-20% level has not yet been performed, present\nresults suggest that such a calculation of the real and imaginary parts of the\nDelta I = 3/2 amplitude should be accomplished within the next two years. The\nmore difficult Delta I = 1/2 amplitude may also be now within reach.",
        "positive": "Scale setting for $\\mathcal{N} = 1$ SUSY Yang-Mills at large-$N$ through\n  volume-reduced twisted matrix model: $\\mathcal{N}=1$ SUSY Yang-Mills theory is an appealing theoretical framework\nthat has been studied in the literature using different methods, including\nstandard lattice simulations. Among these, the volume-reduced twisted\nEguchi-Kawai model, endowed with one adjoint Majorana fermion, could play an\nimportant role in studying its large-$N$ limit via the Curci-Veneziano\nprescription. In this talk, we present our results on the analysis of the scale\nof the theory, performed via different methods based on purely gluonic\nobservables as well as (quenched) fundamental mesons in the chiral limit. These\nlattice results will be used as a scale setting for the analysis of the\nspectrum of the theory."
    },
    {
        "anchor": "Performance of a worm algorithm in $\u03c6^4$ theory at finite quartic\n  coupling: Worm algorithms have been very successful with the simulation of sigma models\nwith fixed length spins which result from scalar field theories in the limit of\ninfinite quartic coupling lambda. Here we investigate closer their algorithmic\nefficiency at finite and even vanishing lambda for the one component model in\ndimensions D = 2, 3, 4.",
        "positive": "Ghost condensation on the lattice: We perform a numerical study of ghost condensation -- in the so-called\nOverhauser channel -- for SU(2) lattice gauge theory in minimal Landau gauge.\nThe off-diagonal components of the momentum-space ghost propagator G^{cd}(p)\nare evaluated for lattice volumes V = 8^4, 12^4, 16^4, 20^4, 24^4 and for three\nvalues of the lattice coupling: \\beta = 2.2, 2.3, 2.4. Our data show that the\nquantity \\phi^b(p) = \\epsilon^{bcd} G^{cd}(p) / 2 is zero within error bars,\nbeing characterized by very large statistical fluctuations. On the contrary,\n|\\phi^b(p)| has relatively small error bars and behaves at small momenta as\nL^{-2} p^{-z}, where L is the lattice side in physical units and z \\approx 4.\nWe argue that the large fluctuations for \\phi^b(p) come from spontaneous\nbreaking of a global symmetry and are associated with ghost condensation. It\nmay thus be necessary (in numerical simulations at finite volume) to consider\n|\\phi^b(p)| instead of \\phi^b(p), to avoid a null average due to tunneling\nbetween different broken vacua. Also, we show that \\phi^b(p) is proportional to\nthe Fourier-transformed gluon field components {\\widetilde A}_{\\mu}^b(q). This\nexplains the L^{-2} dependence of |\\phi^b(p)|, as induced by the behavior of |\n{\\widetilde A}_{\\mu}^b(q) |. We fit our data for |\\phi^b(p)| to the theoretical\nprediction (r / L^2 + v) / (p^4 + v^2), obtaining for the ghost condensate v an\nupper bound of about 0.058 GeV^2. In order to check if v is nonzero in the\ncontinuum limit, one probably needs numerical simulations at much larger\nphysical volumes than the ones we consider. As a by-product of our analysis, we\nperform a careful study of the color structure of the inverse Faddeev-Popov\nmatrix in momentum space."
    },
    {
        "anchor": "Multi-channel S-matrices from energy levels in finite boxes: We show that for a generic quantum mechanical system with more than one open\nscattering channel, it is not possible to fully reconstruct the theory's\nS-matrix from spectral information obtained in large finite volumes with\nperiodic boundary conditions. Physically distinct S-matrices can have identical\nfinite-volume spectra for large finite boxes of arbitrary sizes. If the theory\nis not time-reversal symmetric, there exists an uncountably infinite set of\ndistinct S-matrices with the same spectra. If the theory respects time-reversal\nsymmetry there exists a discrete set of S-matrices with identical energy levels\nfor finite boxes. We illustrate the issue for simple quantum mechanical systems\nin 1+1 dimensions.",
        "positive": "Understanding Parton Distributions from Lattice QCD: I examine the past lattice QCD calculations of three representative\nobservables, the transverse quark distribution, momentum fraction, and axial\ncharge, and emphasize the prospects for not only quantitative comparison with\nexperiment but also qualitative understanding of QCD."
    },
    {
        "anchor": "Dynamics of Langevin Simulation: This chapter [of a supplement to Prog. Theo. Phys.] reviews numerical\nsimulations of quantum field theories based on stochastic quantization and the\nLangevin equation. The topics discussed include renormalization of finite\nstep-size algorithms, Fourier acceleration, and the relation of the Langevin\nequation to hybrid stochastic algorithms and hybrid Monte Carlo.",
        "positive": "Study of the thermal abelian monopoles with proper gauge fixing: The properties of the thermal abelian monopoles are studied in the\ndeconfinement phase of the SU(2) gluodynamics. To remove effects of Gribov\ncopies the simulated annealing algorithm is applied to fix the maximally\nabelian gauge. Computing the density of the thermal abelian monopoles in the\ntemperature range between 1.5T_c and 6.9T_c we show, by comparison with earlier\nresults, that the Gribov copies effects might be as high as 20% making proper\ngauge fixing mandatory. We find that in the infinite temperature limit the\nmonopole density converges to its value in 3-dimensional theory. To study the\ninteraction between monopoles we calculate the monopole-monopole and\nmonopole-antimonopole correlators at different temperatures in the region\n(1.5T_c, 6.9T_c). Using the result of this study we determine the screening\nmass, monopole-monopole coupling constant, monopole size and monopole mass. In\naddition we check the continuum limit of our results."
    },
    {
        "anchor": "Universal signatures of the effective string in finite temperature\n  lattice gauge theories: We study the behaviour of the interquark potential in lattice gauge theories\nat high temperature, but still in the confining phase, and propose a new\nobservable which could play in this regime the same role played by the Luscher\nterm in the low temperature limit. This quantity is related to the exponent of\nthe power prefactor in the effective string partition function or,\nequivalently, to the coefficient of the logarithmic correction in the\ninterquark potential and, as for the usual Luscher term, its value does not\ndepend on the particular gauge group under consideration or on the form of the\neffective string action used to model the flux tube. In this respect it can be\nconsidered as a universal signature of the effective string behaviour of the\nflux tube. As a test of our proposal we studied this quantity with a set of\nhigh-precision numerical simulations in the (2+1) dimensional SU(2), SU(3) and\nSU(4) Yang-Mills theories and in the Z_2 gauge model, always finding a perfect\nagreement with the predicted values.",
        "positive": "Abelian and Center Vortex Condensation in SU(3) Lattice Gauge Theory: We study the condensation of Abelian and Center vortices in SU(3) lattice\ngauge theory at finite temperature. We find that both vortices condense in the\nconfined phase of the SU(3) vacuum."
    },
    {
        "anchor": "Effects of staggered fermions and mixed actions on the scalar correlator: We provide the analytic predictions for the flavor non-singlet scalar\ncorrelator, which will enable determination of the scalar meson mass from the\nlattice scalar correlator. We consider simulations with 2+1 staggered sea\nquarks and staggered or chiral valence quarks. At small u/d masses the\ncorrelator is dominated by the bubble contribution, which is the intermediate\nstate with two pseudoscalar mesons. We determine the bubble contribution within\nStaggered and Mixed Chiral Perturbation Theory.\n  Its effective mass is smaller than the mass M_pi+M_eta, which is the lightest\nintermediate state in proper 2+1 QCD. The unphysical effective mass is a\nconsequence of the taste breaking that makes possible the intermediate state\nwith mass 2*M_pi. We find that the scalar correlator can be negative in the\nsimulations with mixed quark actions if the sea and valence quark masses are\ntuned by matching the pion masses M_{val,val}=M_{pi_5}.",
        "positive": "Quenched results on $B$ Mesons with NRQCD: Preliminary results on spectrum and decay constant of $B$ mesons from a\nquenched simulation at $\\beta = 6.0$ on an $16^3\\times48$ lattice are\ndiscussed. The heavy quark has been implemented using both an NRQCD and the\nstatic formulation, the light one with a clover improved Wilson formulation.\nBoth the NRQCD Hamiltonian and the heavy-light current consistently include\nterms of $O(1/M_{Q})$, the inverse heavy quark mass."
    },
    {
        "anchor": "Chiral expansion for lattice computations of B^{+} to D^{0}K^{+}\n  (\u03c0^{+}) and B^{+} to Dbar^{0} K^{+} (\u03c0^{+}) amplitudes: In this work, we suggest that hard-pion chiral perturbation theory may be\napplicable to the real parts of nonleptonic B^{+} to D^{0}P^{+} and B^{+} to\nDbar^{0}P^{+} (P=K,pi) decay amplitudes. These amplitudes play an important\nrole in the extraction of the angle gamma in the b-d unitarity triangle of the\nCKM matrix, and their real parts can be computed using lattice QCD. We\nconstruct the leading-order operator in the chiral expansion for these\nnonleptonic decays, and discuss the generic features of the\nnext-to-leading-order terms.",
        "positive": "Topological Susceptibility from Slabs: In quantum field theories with topological sectors, a non-perturbative\nquantity of interest is the topological susceptibility chi_t. In principle it\nseems straightforward to measure chi_t by means of Monte Carlo simulations.\nHowever, for local update algorithms and fine lattice spacings, this tends to\nbe difficult, since the Monte Carlo history rarely changes the topological\nsector. Here we test a method to measure chi_t even if data from only one\nsector are available. It is based on the topological charges in sub-volumes,\nwhich we denote as slabs. Assuming a Gaussian distribution of these charges,\nthis method enables the evaluation of chi_t, as we demonstrate with numerical\nresults for non-linear sigma-models."
    },
    {
        "anchor": "Vortex Proliferation and the Dual Superconductor Scenario for\n  Confinement: The 3D Compact U(1) Lattice Higgs Model: It is argued that the phase diagram of the 3D Compact U(1) Lattice Higgs\nModel is more refined than generally thought. The confined and Higgs phases are\nseparated by a well-defined phase boundary, marked by proliferating vortices.\nIt is shown that the confinement mechanism at work is precisely the dual\nsuperconductor scenario.",
        "positive": "One,Two,Zero: Scales of Strong Interactions: We discuss our results on QCD with a number of fundamental fermions ranging\nfrom zero to sixteen. These theories exhibit a wide array of fascinating\nphenomena which have been under close scrutiny, especially in recent years,\nfirst and foremost is the approach to conformality. To keep this review\nfocused, we have chosen scale generation, or lack thereof as a guiding theme,\nhowever the discussion will be set in the general framework of the analysis of\nthe phases and phase transitions of strong interactions at zero and nonzero\ntemperature."
    },
    {
        "anchor": "Monte Carlo Renormalization of 2d Simplicial Quantum Gravity Coupled to\n  Gaussian Matter: We extend a recently proposed real-space renormalization group scheme for\ndynamical triangulations to situations where the lattice is coupled to\ncontinuous scalar fields. Using Monte Carlo simulations in combination with a\nlinear, stochastic blocking scheme for the scalar fields we are able to\ndetermine the leading eigenvalues of the stability matrix with good accuracy\nboth for c = 1 and c = 10 theories.",
        "positive": "Heavy quark mass dependence of semileptonic form factors for B decays: We present our study of the dependence of the heavy-to-light semileptonic B\ndecay form factors on the heavy-light meson mass $M_{PS}$. Simulations are made\nover a range of the heavy quark mass covering both the charm and bottom quarks\nusing the $O(a)$-improved clover action at $\\beta=5.9$ on a $16^3\\times 40$ and\n$24^3\\times 64$ lattice. We find that a weak dependence of form factors on\n$M_{PS}$ observed in previous studies in the region of charm quark persists up\nto the region of$b$ quark. The soft pion relation $f^0(q^2_{max})=f_B/f_\\pi$ is\nexamined and found to be largely violated."
    },
    {
        "anchor": "Evolution of the coupling constant in SU(2) lattice gauge theory with\n  two adjoint fermions: We measure the evolution of the coupling constant using the Schroedinger\nfunctional method in the lattice formulation of SU(2) gauge theory with two\nmassless Dirac fermions in the adjoint representation. We observe strong\nevidence for an infrared fixed point, where the theory becomes conformal. We\nmeasure the continuum beta-function and the coupling constant as a function of\nthe energy scale.",
        "positive": "Lattice QCD Application Development within the US DOE Exascale Computing\n  Project: In October, 2016, the US Department of Energy launched the Exascale Computing\nProject, which aims to deploy exascale computing resources for science and\nengineering in the early 2020's. The project brings together application teams,\nsoftware developers, and hardware vendors in order to realize this goal.\nLattice QCD is one of the applications. Members of the US lattice gauge theory\ncommunity with significant collaborators abroad are developing algorithms and\nsoftware for exascale lattice QCD calculations. We give a short description of\nthe project, our activities, and our plans."
    },
    {
        "anchor": "Solution of the Complex Action Problem in the Potts Model for Dense QCD: Monte Carlo simulations of lattice QCD at non-zero baryon chemical potential\n$\\mu$ suffer from the notorious complex action problem. We consider QCD with\nstatic quarks coupled to a large chemical potential. This leaves us with an\nSU(3) Yang-Mills theory with a complex action containing the Polyakov loop.\nClose to the deconfinement phase transition the qualitative features of this\ntheory, in particular its Z(3) symmetry properties, are captured by the 3-d\n3-state Potts model. We solve the complex action problem in the Potts model by\nusing a cluster algorithm. The improved estimator for the $\\mu$-dependent part\nof the Boltzmann factor is real and positive and is used for importance\nsampling. We localize the critical endpoint of the first order deconfinement\nphase transition line and find consistency with universal 3-d Ising behavior.\nWe also calculate the static quark-quark, quark-anti-quark, and\nanti-quark-anti-quark potentials which show screening as expected for a system\nwith non-zero baryon density.",
        "positive": "Magnetic properties of the neutron in a uniform background field: We present calculations of the magnetic moment and magnetic polarisability of\nthe neutron from the background field method. The calculations are performed on\n$32^3\\times64$ dynamical lattices generated by the PACS-CS collaboration and\nmade available via the ILDG. We consider uniform fields quantised by the\nperiodic spatial volume. We explore different approaches for improving the\nquality of the fits used in the results. Also included are initial results for\nthe magnetic moment of the lowest lying negative parity nucleon states."
    },
    {
        "anchor": "Monte Carlo simulation of the SU(3) spin model with chemical potential\n  in a flux representation: We present a simulation of the SU(3) spin model with chemical potential using\na recently proposed flux representation. In this representation the complex\nphase problem is avoided and a Monte Carlo simulation in terms of the fluxes\nbecomes possible. We explore the phase diagram of the model as a function of\ntemperature and chemical potential.",
        "positive": "The second moment of the pion's distribution amplitude: We present preliminary results for the second moment of the pion's\ndistribution amplitude. The lattice formulation and the phenomenological\nimplications are briefly reviewed, with special emphasis on some subtleties\nthat arise when the Lorentz group is replaced by the hypercubic group. Having\nanalysed more than half of the available configurations, the result obtained is\n\\xi^2_L = 0.06 \\pm 0.02."
    },
    {
        "anchor": "Fermion Actions extracted from Lattice Super Yang-Mills Theories: We revisit 2D $\\mathcal{N}=(2,2)$ super Yang-Mills lattice formulation\n(Sugino model) to investigate its fermion action with two (Majorana) fermion\nflavors and exact chiral-$U(1)_{R}$ symmetry. We show that the reconcilement of\nchiral symmetry and absence of further species-doubling originates in the 4D\nclifford algebra structure of the action, where 2D two flavors are spuriously\ntreated as a single 4D four-spinor with four 4D gamma matrices introduced into\nkinetic and Wilson terms. This fermion construction based on the\nhigher-dimensional clifford algebra is extended to four dimensions in two\nmanners: (1) pseudo-8D sixteen-spinor treatment of 4D four flavors with eight\n8D gamma matrices, (2) pseudo-6D eight-spinor treatment of 4D two flavors with\nfive out of six 6D gamma matrices. We obtain 4D four-species and two-species\nlattice fermions with unbroken subgroup of chiral symmetry and other essential\nproperties. We discuss their relations to staggered and Wilson twisted-mass\nfermions. We also discuss their potential feedback to 4D super Yang-Mills\nlattice formulations.",
        "positive": "Curci-Ferrari mass and the Neuberger problem: We study the massive Curci-Ferrari model as a starting point for defining\nBRST quantisation for Yang-Mills theory on the lattice. In particular, we\nelucidate this proposal in light of topological approaches to gauge-fixing and\nstudy the case of a simple one-link Abelian model."
    },
    {
        "anchor": "The analytic structure of the Landau gauge quark propagator from Pad\u00e9\n  analysis: The analytic structure of the 2 flavour full QCD lattice Landau gauge quark\npropagator is investigated with Pad\\'e approximants applied to its vector and\nscalar form factors. No poles at complex momentum are observed for the\npropagator. Moreover, there is clear evidence of a pole at real on-axis\nnegative Euclidean momentum, i.e. for Minkowski type of momentum. %, with a\npositive residuum. This pole occurs at Euclidean momenta $p^2 \\sim - 300$ MeV\nand it reproduces typical quark mass values used in phenomenological effective\nquark models. The Pad\\'e approximant analysis also gives hints on the presence\nof a branch cut. Our results also show a clear correlation between the position\nof this pole, understood as an effective quark mass, and the pion mass that is\ncompatible with PCAC. Slightly differences between the poles for the two quark\nform factors are observed which can be viewed either as a limitation of the\nmethod or as a suggestion that the quark propagator has no spectral\nrepresentation.",
        "positive": "Landau-gauge propagators in Yang-Mills theories at beta = 0: massive\n  solution versus conformal scaling: We study Landau-gauge gluon and ghost propagators in Yang-Mills theories at\nlattice parameter beta = 0, considering relatively large lattice volumes for\nthe case of the SU(2) gauge group in three and four space-time dimensions. We\ncompare the lattice data to the so-called massive and conformal-scaling\nsolutions, examining the requirements for a good description of the propagators\nover various ranges of momenta and discussing possible systematic errors. Our\nanalysis strongly supports the massive solution, i.e. a finite gluon propagator\nand an essentially free ghost propagator in the infrared limit, in disagreement\nwith Ref. [1]. Moreover, we argue that discretization effects play no role in\nthe analysis of these propagators."
    },
    {
        "anchor": "Strings of diquark-quark (QQ)Q baryon before phase transition: We explore the limit at which the effective baryonic Y-string model of the\njunction approaches the mesonic stringlike behavior. We calculate and compare\nthe numerical values of the static potential and energy-density correlators of\ndiquark-quark and quark-antiquark configurations. The gauge model is pure\nYang-Mills $SU(3)$ lattice gauge theory at coupling $\\beta=6.0$ and finite\ntemperature. The diquark setup is approximated as two quarks confined within a\nsphere of radius $0.1$ fm. The lattice data of the potential and energy show\nthat the string binding the diquark-quark configuration displays an identical\nbehavior to the quark-antiquark confining string. However, with the temperature\nincrease to a small enough neighborhood of the critical point $T_{c}$, the\ngluonic similarities between the two systems do not manifest neither at short\nnor intermediate distance scales $R<1.0$ fm. The comparison between the\npotential and the second moment of the action-density correlators for both\nsystems shows significant splitting. This suggests that subsisted baryonic\ndecoupled states overlap with the mesonic spectrum. The baryonic junction's\nmodel for the potential and the profile returns a good fit to the numerical\nlattice data of the diquark-quark arrangement. However, near the critical\npoint, the mesonic string displays large deviations compared to fits of the\ncorresponding quark-antiquark data.",
        "positive": "O(2) symmetry breaking vs. vortex loop percolation: We study with lattice Monte Carlo simulations the relation of global O(2)\nsymmetry breaking in three dimensions to the properties of a geometrically\ndefined vortex loop network. We find that different definitions of constructing\na network lead to different results even in the thermodynamic limit, and that\nwith typical definitions the percolation transition does not coincide with the\nthermodynamic phase transition. These results show that geometrically defined\npercolation observables need not display universal properties related to the\ncritical behaviour of the system, and do not in general survive in the field\ntheory limit."
    },
    {
        "anchor": "First Order Phase Transition in Finite Density QCD using the modulus of\n  the Dirac Determinant: We report results of simulations of strong coupling, finite density QCD\nobtained within a MFA inspired approach where the fermion determinant in the\nintegration measure is replaced by its absolute value. Contrary to the standard\nwisdom, we show that within this approach a clear signal of a phase transition\nappears with a critical chemical potential in extremely good agreement with the\nresults obtained with the Glasgow algorithm. The modulus of the fermion\ndeterminant seems therefore to preserve some of the relevant physical\nproperties of the system. We also analyze the dependence of our results on the\nquark mass, including both the chiral and large mass limit, and the theory in\nthe quenched approximation.",
        "positive": "The Phase Diagram of the Gonihedric 3d Ising Model via CVM: We use the cluster variation method (CVM) to investigate the phase structure\nof the 3d gonihedric Ising actions defined by Savvidy and Wegner. The\ngeometrical spin cluster boundaries in these systems serve as models for the\nstring worldsheets of the gonihedric string embedded in ${\\bf Z}^3$. The models\nare interesting from the statistical mechanical point of view because they have\na vanishing bare surface tension. As a result the action depends only on the\nangles of the discrete surface and not on the area, which is the antithesis of\nthe standard 3d Ising model.\n  The results obtained with the CVM are in good agreement with Monte Carlo\nsimulations for the critical temperatures and the order of the transition as\nthe self-avoidance coupling $\\kappa$ is varied. The value of the magnetization\ncritical exponent $\\beta = 0.062 \\pm 0.003$, calculated with the cluster\nvariation--Pad\\`e approximant method, is also close to the simulation results."
    },
    {
        "anchor": "Time-dependent correlation functions in a one-dimensional asymmetric\n  exclusion process: We study a one-dimensional anisotropic exclusion process describing particles\ninjected at the origin, moving to the right on a chain of $L$ sites and being\nremoved at the (right) boundary. We construct the steady state and compute the\ndensity profile, exact expressions for all equal-time n-point density\ncorrelation functions and the time-dependent two-point function in the steady\nstate as functions of the injection and absorption rates. We determine the\nphase diagram of the model and compare our results with predictions from\ndynamical scaling and discuss some conjectures for other exclusion models.",
        "positive": "Evaluating the Fermionic Determinant of Dynamical Configurations: We propose and study an improved method to calculate the fermionic\ndeterminant of dynamical configurations. The evaluation or at least stochastic\nestimation of ratios of fermionic determinants is essential for a recently\nproposed updating method of smeared link dynamical fermions. This update\ncreates a sequence of configurations by changing a subset of the gauge links by\na pure gauge heat bath or over relaxation step. The acceptance of the proposed\nconfiguration depends on the ratio of the fermionic determinants on the new and\noriginal configurations. We study this ratio as the function of the number of\nlinks that are changed in the heat bath update. We find that even when every\nlink of a given direction and parity of a 10fm^4 configuration is updated, the\naverage of the determinant ratio is still close to one and with the improved\nstochastic estimator the proposed change is accepted with about 20%\nprobability. This improvement suggests that the new updating technique can be\nefficient even on large lattices."
    },
    {
        "anchor": "QCD Thermodynamics with 2 and 3 Quark Flavors: We discuss the flavor dependence of the pressure and critical temperature\ncalculated in QCD with 2, 2+1 and 3 flavors using improved gauge and staggered\nfermion actions on lattices with temporal extent Nt=4. For T > 2 Tc we find\nthat bulk thermodynamics of QCD with 2 light and a heavier strange quark is\nwell described by 3-flavor QCD while the transition temperature is closer to\nthat of 2-flavor QCD. Furthermore, we present evidence that the chiral critical\npoint of 3-flavor QCD, i.e. the second order endpoint of the line of first\norder chiral phase transitions, belongs to the universality class of the 3d\nIsing model.",
        "positive": "Equation of State for physical quark masses: We calculate the QCD equation of state for temperatures corresponding to the\ntransition region with physical mass values for two degenerate light quark\nflavors and a strange quark using an improved staggered fermion action\n(p4-action) on lattices with temporal extent N_tau=8. We compare our results\nwith previous calculations performed at twice larger values of the light quark\nmasses as well as with results obtained from a resonance gas model calculation.\nWe also discuss the deconfining and chiral aspects of the QCD transition in\nterms of renormalized Polyakov loop, strangeness fluctuations and subtracted\nchiral condensate. We show that compared to the calculations performed at twice\nlarger value of the light quark mass the transition region shifts by about 5\nMeV toward smaller temperatures"
    },
    {
        "anchor": "The Gluon Propagator on a Large Volume, at $\u03b2=6.0$: We present the results of a high statistics lattice study of the gluon\npropagator, in the Landau gauge, at $\\beta=6.0$. As suggested by previous\nstudies, we find that, in momentum space, the propagator is well described by\nthe expression $G(k^2)= \\Big[ M^2 + Z\\cdot k^2(k^2/\\Lambda^2)^\\eta\\Big]^{-1} $.\nBy comparing $G(k^2)$ on different volumes, we obtain a precise determination\nof the exponent $\\eta=0.532(12)$, and verify that $M^2$ does not vanish in the\ninfinite volume limit. The behaviour of $\\eta$ and $M^2$ in the continuum limit\nis not known, and can only be studied by increasing the value of $\\beta$.",
        "positive": "Algebraic Generalization of the Ginsparg-Wilson Relation: A specific algebraic realization of the Ginsparg-Wilson relation in the form\n$\\gamma_{5}(\\gamma_{5}D)+(\\gamma_{5}D)\\gamma_{5} =\n  2a^{2k+1}(\\gamma_{5}D)^{2k+2}$ is discussed, where $k$ stands for a\nnon-negative integer and $k=0$ corresponds to the commonly discussed\nGinsparg-Wilson relation. From a view point of algebra, a characteristic\nproperty of our proposal is that we have a closed algebraic relation for one\nunknown operator $D$, although this relation itself is obtained from the\noriginal proposal of Ginsparg and Wilson,\n$\\gamma_{5}D+D\\gamma_{5}=2aD\\gamma_{5} \\alpha D$, by choosing $\\alpha$ as an\noperator containing $D$ (and thus Dirac matrices). In this paper, it is shown\nthat we can construct the operator $D$ explicitly for any value of $k$. We\nfirst show that the instanton-related index of all these operators is\nidentical. We then illustrate in detail a generalization of Neuberger's overlap\nDirac operator to the case $k=1$. On the basis of explicit construction, it is\nshown that the chiral symmetry breaking term becomes more irrelevent for larger\n$k$ in the sense of Wilsonian renormalization group. We thus have an infinite\ntower of new lattice Dirac operators which are topologically proper, but a\nlarge enough lattice is required to accomodate a Dirac operator with a large\nvalue of $k$."
    },
    {
        "anchor": "Asymptotic lattice spacing dependence of spectral quantities in lattice\n  QCD with Wilson or Ginsparg-Wilson quarks: One major systematic uncertainty of lattice QCD results is due to the\ncontinuum extrapolation. For an asymptotically free theory like QCD one finds\ncorrections of the form\n$a^{n_\\mathrm{min}}[2b_0\\bar{g}^2(1/a)]^{\\hat{\\Gamma}_i}$ with lattice spacing\n$a$, where $\\bar{g}(1/a)$ is the running coupling at renormalisation scale\n$\\mu=1/a$ and $n_\\mathrm{min}$ is a positive integer. $\\hat{\\Gamma}_i$ can take\nany positive or negative value, but is computable by next-to-leading order\nperturbation theory. It will impact convergence towards the continuum limit.\nBalog, Niedermayer and Weisz first pointed out how problematic such corrections\ncan be in their seminal work for the O(3) model. Based on Symanzik Effective\nTheory for lattice QCD with Ginsparg-Wilson and Wilson quarks, various powers\n$\\hat{\\Gamma}_i$ are found due to lattice artifacts from the discretised\nlattice action. Those powers are sufficient when describing spectral\nquantities, while non-spectral quantities will require additional powers\noriginating from corrections to each of the discretised local fields involved.\nThis new input should be incorporated into ans\\\"atze used for the continuum\nextrapolation.",
        "positive": "Domain Decomposition method on GPU cluster: Pallalel GPGPU computing for lattice QCD simulations has a bottleneck on the\nGPU to GPU data communication due to the lack of the direct data exchanging\nfacility. In this work we investigate the performance of quark solver using the\nrestricted additive Schwarz (RAS) preconditioner on a low cost GPU cluster. We\nexpect that the RAS preconditioner with appropriate domaindecomposition and\ntask distribution reduces the communication bottleneck. The GPU cluster we\nconstructed is composed of four PC boxes, two GPU cards are attached to each\nbox, and we have eight GPU cards in total. The compute nodes are connected with\nrather slow but low cost Gigabit-Ethernet. We include the RAS preconditioner in\nthe single-precision part of the mixedprecision nested-BiCGStab algorithm and\nthe single-precision task is distributed to the multiple GPUs. The benchmarking\nis done with the O(a)-improved Wilson quark on a randomly generated gauge\nconfiguration with the size of $32^4$. We observe a factor two improvment on\nthe solver performance with the RAS precoditioner compared to that without the\npreconditioner and find that the improvment mainly comes from the reduction of\nthe communication bottleneck as we expected."
    },
    {
        "anchor": "Numerical evidence of the axial magnetic effect: The axial magnetic field, which couples to left- and right-handed fermions\nwith opposite signs, may generate an equilibrium dissipationless energy flow of\nfermions in the direction of the field even in the presence of interactions. We\nreport on numerical observation of this Axial Magnetic Effect in quenched SU(2)\nlattice gauge theory. We find that in the deconfinement (plasma) phase the\nenergy flow grows linearly with the increase of the strength of the axial\nmagnetic field. In the confinement (hadron) phase the Axial Magnetic Effect is\nabsent. Our study indirectly confirms the existence of the Chiral Vortical\nEffect since both these effects have the same physical origin related to the\npresence of the gravitational anomaly.",
        "positive": "A first look at maximally twisted mass lattice QCD calculations at the\n  physical point: In this contribution, a first look at simulations using maximally twisted\nmass Wilson fermions at the physical point is presented. A lattice action\nincluding clover and twisted mass terms is presented and the Monte Carlo\nhistories of one run with two mass-degenerate flavours at a single lattice\nspacing are shown. Measurements from the light and heavy-light pseudoscalar\nsectors are compared to previous $N_f = 2$ results and their phenomenological\nvalues. Finally, the strategy for extending simulations to $N_f = 2 + 1 + 1$ is\noutlined."
    },
    {
        "anchor": "Vortices in $SO(3)\\times Z(2)$ simulations: We explore simulations on periodic lattices in the Tomboulis $SO(3)\\times\nZ(2)$ formulation. The dynamical variables are constrained. We propose an\nupdate algorithm that satisfies the constraints and is straightforward to\nimplement. We show how boundary conditions put constraints on the configuration\nspace.",
        "positive": "Decay Constants of Pseudoscalar Mesons to Two Loops in Three-Flavor\n  Partially Quenched $\u03c7$PT: This paper presents a first study of the decay constants of the charged, or\nflavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea\nquarks, in Partially Quenched Chiral Perturbation Theory (PQ$\\chi$PT). Explicit\nanalytical expressions up to ${\\cal O}(p^6)$ in the momentum expansion are\ngiven. The calculations have been performed within the supersymmetric\nformulation of PQ$\\chi$PT. We also present some numerical results to indicate\nthe size of the corrections."
    },
    {
        "anchor": "Charmonium correlators at finite temperature in quenched lattice QCD: We study charmonium correlators at finite temperature using quenched lattice\nQCD simulations. Two analysis procedures are applied to extract information on\nthe spectral function: the maximum entropy method, and the $\\chi^2$ fit\nanalyses including the constrained curve fitting. We focus on the low energy\nstructure of the spectral function by applying the smearing technique. We first\ndiscuss the applicability of these methods to the finite temperatures by\nanalyzing the data at T=0 with restricted numbers of degrees of freedom. Then\nwe apply these methods to the correlators at $T>0$. We find no indication of\nmass shift and finite width for the charmonium states at $T\\simeq 0.9T_c$. The\nresults at $T\\simeq 1.1 T_c$ imply that bound-state-like structures may survive\neven above $T_c$.",
        "positive": "An estimate of heavy quark momentum diffusion coefficient in gluon\n  plasma: We calculate the momentum diffusion coefficient for heavy quarks in SU(3)\ngluon plasma at temperatures 1-2 times the deconfinement temperature. The\nmomentum diffusion coefficient is extracted from a Monte Carlo calculation of\nthe correlation function of color electric fields, in the leading order of\nexpansion in heavy quark mass. Systematics of the calculation are examined, and\ncompared with perturbtion theory and other estimates."
    },
    {
        "anchor": "Lattice calculation of $1^{-+}$ hybrid mesons with improved\n  Kogut-Susskind fermions: We report on a lattice determination of the mass of the exotic $1^{-+}$\nhybrid meson using an improved Kogut-Susskind action. Results from both\nquenched and dynamical quark simulations are presented. We also compare with\nearlier results using Wilson quarks at heavier quark masses. The results on\nlattices with three flavors of dynamical quarks show effects of sea quarks on\nthe hybrid propagators which probably result from coupling to two meson states.\nWe extrapolate the quenched results to the physical light quark mass to allow\ncomparison with experimental candidates for the $1^{-+}$ hybrid meson. The\nlattice result remains somewhat heavier than the experimental result, although\nit may be consistent with the $\\pi_1(1600)$.",
        "positive": "The ${\\cal O}(g^6)$ coefficient in the thermodynamic potential of hot\n  SU(N) Gauge Theories and MQCD: The non-perturbative input necessary for the determination of the ${\\cal\nO}(g^6)$ part of the weak coupling expansion of the free energy density for\nSU(2) and SU(3) gauge theories is estimated. Although the perturbative\ninformation completing the contribution to this order is missing, we give\narguments that the magnetic fluctuations are dominated by screened elementary\nmagnetic gluons."
    },
    {
        "anchor": "Study of spatial meson correlators at finite temperature in quenched\n  anisotropic lattice QCD: We analyze the meson correlator in the spatial direction at finite\ntemperature. To achieve fine resolution in the spatial direction, we use an\nanisotropic lattice with the standard Wilson plaquette gauge action and the\n$O(a)$ improved Wilson quark action. Below and above $T_c$, properties of\ncorrelators are investigated by two methods: fits with ansatz for the spectral\nfunction, and direct reconstruction of the spectral function using the maximum\nentropy method.",
        "positive": "Investigation of Doubly Heavy Tetraquark Systems using Lattice QCD: We search for possibly existent bound states in the heavy-light tetraquark\nchannels with quark content $ \\bar{b}\\bar{b}ud $, $ \\bar{b}\\bar{b}us $ and $\n\\bar{b}\\bar{c}ud $ using lattice QCD. We carry out calculations on several\ngauge link ensembles with $ N_f=2+1 $ flavours of domain-wall fermions and\nconsider a basis of local and non-local interpolators. Besides extracting the\nenergy spectrum from the correlation matrices, we also perform a L\\\"uscher\nanalysis to extrapolate our results to infinite volume."
    },
    {
        "anchor": "Volume independence of large-N QCD with adjoint fermions: It has been proposed that four-dimensional QCD with fermions in the adjoint\nrepresentation exhibits volume-independence in the large-N limit. If correct,\nthis would mean that results for physical quantities could be obtained from the\nsingle-site version of the model. A necessary condition for volume-independence\nis that the (Z_N)^4 center-symmetry of the single-site theory is unbroken. We\nexplore the phase diagram of the theory with a single Dirac fermion using\nWilson fermions for a number of colors in the range N=8-15, and identify the\nregion in the parameter space of quark mass and gauge coupling where the\nsymmetry appears to be unbroken. Our evidence suggests that this region\nincludes both light and heavy quarks, and our results are consistent with this\nregion extending to the continuum limit.",
        "positive": "The kaon semileptonic form factor with near physical domain wall quarks: We present a new calculation of the K->pi semileptonic form factor at zero\nmomentum transfer in domain wall lattice QCD with Nf=2+1 dynamical quark\nflavours. By using partially twisted boundary conditions we simulate directly\nat the phenomenologically relevant point of zero momentum transfer. We perform\na joint analysis for all available ensembles which include three different\nlattice spacings (a=0.09-0.14fm), large physical volumes (m_pi*L>3.9) and pion\nmasses as low as 171 MeV. The comprehensive set of simulation points allows for\na detailed study of systematic effects leading to the prediction\nf+(0)=0.9670(20)(+18/-46), where the first error is statistical and the second\nerror systematic. The result allows us to extract the CKM-matrix element\n|Vus|=0.2237(+13/-8) and confirm first-row CKM-unitarity in the Standard Model\nat the sub per mille level."
    },
    {
        "anchor": "Chiral and Continuum Extrapolation of Partially-Quenched Lattice Results: The vector meson mass is extracted from a large sample of partially quenched,\ntwo-flavor lattice QCD simulations. For the first time, discretisation,\nfinite-volume and partial quenching artefacts are treated in a unified\nframework which is consistent with the low-energy behaviour of QCD. This\nanalysis incorporates the leading infrared behaviour dictated by chiral\neffective field theory. As the two-pion decay channel cannot be described by a\nlow-energy expansion alone, a highly-constrained model for the decay channel of\nthe rho-meson is introduced. The latter is essential for extrapolating lattice\nresults from the quark-mass regime where the rho is observed to be a physical\nbound state.",
        "positive": "Sigma resonance parameters from a $N_f=2$ lattice QCD simulation: In this work we present the analysis of the energy spectrum from a recent\ntwo-flavor ($N_f=2$) lattice QCD calculation for pion-pion scattering in the\nscalar, isoscalar channel (the $\\sigma$-meson). The lattice simulation was\nperformed for two quark masses corresponding to a pion mass of 315 MeV and 227\nMeV. The $\\sigma$-meson parameters are extracted using various parametrizations\nof the scattering amplitude. The results obtained from a chiral unitary\nparametrization are extrapolated to the physical point and read $M_\\sigma =(\n440^{+10}_{-16}(50) - i\\,240(20)(25))$ MeV, where the uncertainties in the\nparentheses denote the stochastic and systematic ones. The behavior of the\n$\\sigma$-meson parameters with increasing pion mass is discussed as well."
    },
    {
        "anchor": "Non-perturbative renormalization of bilinear operators with dynamical\n  overlap fermions: Using the non-perturbative renormalization technique, we calculate the\nrenormalization factors for quark bilinear operators made of overlap fermions\non the lattice. The background gauge field is generated by the JLQCD and TWQCD\ncollaborations including dynamical effects of two or 2+1 flavors of light\nquarks on a 16$^3\\times$32 or 16$^3\\times$48 lattice at lattice spacing around\n0.1 fm. By reducing the quark mass close to the chiral limit, where the finite\nvolume system enters the so-called $\\epsilon$-regime, the unwanted effect of\nspontaneous chiral symmetry breaking on the renormalization factors is\nsuppressed. On the lattices in the conventional $p$-regime, this effect is\nprecisely subtracted by separately calculating the contributions from the\nchiral condensate.",
        "positive": "Light-by-light forward scattering amplitudes in Lattice QCD: We present our preliminary results on the calculation of hadronic\nlight-by-light forward scattering amplitudes using vector four-point\ncorrelation functions computed on the lattice. Using a dispersive approach,\nforward scattering amplitudes can be described by $\\gamma^* \\gamma^* \\to$\nhadrons fusion cross sections and then compared with phenomenology. We show\nthat only a few states are needed to reproduce our data. In particular, the sum\nrules considered in this study imply relations between meson$-\\gamma\\gamma$\ncouplings and provide valuable information about individual form factors which\nare often used to estimate the meson-pole contributions to the hadronic\nlight-by-light contribution to the $(g-2)$ of the muon."
    },
    {
        "anchor": "Improved stochastic estimation of quark propagation with Laplacian\n  Heaviside smearing in lattice QCD: A new method of stochastically estimating the low-lying effects of quark\npropagation is proposed which allows accurate determinations of temporal\ncorrelations of single-hadron and multi-hadron operators in lattice QCD. The\nmethod is well suited for calculations in large volumes. Contributions\ninvolving quark propagation connecting hadron sink operators at the same final\ntime can be handled in a straightforward manner, even for a large number of\nfinal time slices. The method exploits Laplacian Heaviside (LapH) smearing. ZN\nnoise is introduced in a novel way, and variance reduction is achieved using\njudiciously-chosen noise dilution projectors. The method is tested using\nisoscalar mesons in the scalar, pseudoscalar, and vector channels, and using\nthe two-pion system of total isospin I=0,1,2 on large anisotropic 24^3 x 128\nlattices with spatial spacing a_s~0.12 fm and temporal spacing a_t~0.034 fm for\npion masses mpi~390 and 240 MeV.",
        "positive": "Numerical Study of $ K^0$--$\\bar{K}^0$ Mixing and $ B_K $: We have computed $ B_K $ with staggered fermions, using two different\nmethods: both in the one spin trace form and two spin trace form. Renormalized\nresults in both forms are in good agreement. The numerical simulations were\nperformed on a $ 16^3 \\times 40 $ lattice in full QCD with $ \\beta = 5.7 $. We\nalso tried an improved wall source method in order to select only the\npseudo-Goldstone bosons and compare the numerical results obtained with those\nfrom the conventional wall source method. We have studied $ B_K $ with a series\nof non-degenerate quark anti-quark pairs and saw no effect on $ B_K $, although\ndramatic effects in the chiral limit were seen on the individual terms making\nup $ B_K $."
    },
    {
        "anchor": "The critical line of two-flavor QCD at finite isospin or baryon\n  densities from imaginary chemical potentials: We determine the (pseudo)critical lines of QCD with two degenerate staggered\nfermions at nonzero temperature and quark or isospin density, in the region of\nimaginary chemical potentials; analytic continuation is then used to prolongate\nto the region of real chemical potentials. We obtain an accurate determination\nof the curvatures at zero chemical potential, quantifying the deviation between\nthe case of finite quark and of finite isospin chemical potential. Deviations\nfrom a quadratic dependence of the pseudocritical lines on the chemical\npotential are clearly seen in both cases: we try different extrapolations and,\nfor the case of nonzero isospin chemical potential, confront them with the\nresults of direct Monte Carlo simulations. Finally we find that, as for the\nfinite quark density case, an imaginary isospin chemical potential can\nstrengthen the transition till turning it into strong first order.",
        "positive": "Scale setting for QCD with Nf=3+1 dynamical quarks: We present first results of the scale setting for QCD with Nf=3+1 dynamical\nquarks on the lattice. We use a recently proposed massive renormalization\nscheme with a non-perturbatively determined clover coefficient. To relate the\nbare coupling of the simulations to a lattice spacing in fm, we measure the\nflow scale t0 in lattice units at a mass point with degenerate light quark\nmasses and a physical charm quark mass, where its value in physical units is\nknown. We discuss the setup, tuning procedure, simulation parameters and\nmeasurement results for ensembles with three different volumes and present a\ncharmonium spectrum."
    },
    {
        "anchor": "Spin on the lattice: I review the current status of hadronic structure computations on the\nlattice. I describe the basic lattice techniques and difficulties and present\nsome of the latest lattice results; in particular recent results of the RBC\ngroup using domain wall fermions are also discussed.",
        "positive": "The twisted gradient flow coupling at one loop: We compute the one-loop running of the $SU(N)$ 't Hooft coupling in a finite\nvolume gradient flow scheme using twisted boundary conditions. The coupling is\ndefined in terms of the energy density of the gradient flow fields at a scale\n$\\tilde{l}$ given by an adequate combination of the torus size and the rank of\nthe gauge group, and is computed in the continuum using dimensional\nregularization. We present the strategy to regulate the divergences for a\ngeneric twist tensor, and determine the matching to the $\\overline{\\rm MS}$\nscheme at one-loop order. For the particular case in which the twist tensor is\nnon-trivial in a single plane, we evaluate the matching coefficient numerically\nand determine the ratio of $\\Lambda$ parameters between the two schemes. We\nanalyze the $N$ dependence of the results and the possible implications for\nnon-commutative gauge theories and volume independence."
    },
    {
        "anchor": "Electromagnetic contribution to $\u03a3$-$\u039b$ mixing using lattice\n  QCD+QED: Mixing in the $\\Sigma^0$-$\\Lambda^0$ system is a direct consequence of broken\nisospin symmetry and is a measure of both isospin-symmetry breaking as well as\ngeneral SU(3)-flavour symmetry breaking. In this work we present a new scheme\nfor calculating the extent of $\\Sigma^0$-$\\Lambda^0$ mixing using simulations\nin lattice QCD+QED and perform several extrapolations that compare well with\nvarious past determinations. Our scheme allows us to easily contrast the\nQCD-only mixing case with the full QCD+QED mixing.",
        "positive": "Update on the Sea Contributions to Hadron Electric Polarizabilities\n  through Reweighting: We present the results of a reweighting calculation to compute the\ncontribution of the charged quark sea to the neutron electric polarizability.\nThe chief difficulty is the stochastic estimation of weight factors, and we\npresent a hopping parameter expansion-based technique for reducing the\nstochastic noise, along with a discussion of why this particular reweighting is\nso difficult. We used this technique to estimate weight factors for 300\nconfigurations of nHYP-clover fermions and compute the neutron polarizability,\nbut the reweighting greatly inflates the overall statistical error, driven by\nthe stochastic noise in the weight factors."
    },
    {
        "anchor": "A Complete Lattice Technicolor Model: We construct a lattice gauge theory using reduced staggered fermions and\ngauge fields which provides a non-perturbative realization of a {\\it complete}\ntechnicolor model; one which treats both strong and weakly coupled gauge\nsectors on an equal footing. We show that the model is capable of developing a\nHiggs phase at non zero lattice spacing via the formation of fermion\ncondensates. We further show that while the broken symmetry associated with\nthis phase has a vector character in the lattice theory it is realized as an\naxial symmetry in the continuum limit in agreement with the Vafa Witten\ntheorem. We discuss our result in the context of universality",
        "positive": "Equation of state and Taylor expansions at nonzero isospin chemical\n  potential: We compute the equation of state of isospin asymmetric QCD at zero and\nnon-zero temperatures using direct simulations of lattice QCD with three\ndynamical flavors at physical quark masses. In addition to the pressure and the\ntrace anomaly and their behavior towards the continuum limit, we will\nparticularly discuss the extraction of the speed of sound. Furthermore, we\ndiscuss first steps towards the extension of the EoS to small non-zero baryon\nchemical potentials via Taylor expansion."
    },
    {
        "anchor": "Magnetic operators in 2D compact scalar field theories on the lattice: In lattice compact gauge theories, we must impose the admissibility condition\nto have well-defined topological sectors. The admissibility condition, however,\nusually forbids the presence of magnetic operators, and it is not so trivial if\none can study the monopole physics depending on the topological term, such as\nthe Witten effect, on the lattice. In this paper, we address this question in\nthe case of 2D compact scalars as it would be one of the simplest examples\nhaving analogues of the monopole and the topological term. To define the\nmagnetic operator, we propose the ``excision method,'' which consists of\nexcising lattice links (or bonds) in an appropriate region containing the\nmonopole and defining the dual lattice in a particular way. The size of the\nexcised region is $O(1)$ in lattice units so that the monopole becomes\npoint-like in the continuum limit. We give the lattice derivation of the\n't~Hooft anomalies between the electric and magnetic symmetries and also derive\nthe higher-group-like structure related to the Witten effect.",
        "positive": "Further Investigation of Massive Landau-Gauge Propagators in the\n  Infrared Limit: We investigate how the infrared behavior of electric and magnetic gluon\npropagators in Landau gauge is affected by temperature. More precisely, we\nperform large-lattice simulations in pure SU(2) gauge theory around the\ntransition temperature Tc and study the longitudinal (electric) and transverse\n(magnetic) gluon propagators in momentum space, proposing the calculation of\nscreening masses through an Ansatz from the zero-temperature case. Going from\nzero to nonzero temperature, we see that the longitudinal gluon propagator\nDL(p) is enhanced, with an apparent plateau value in the infrared, while the\ntransverse propagator DT(p) gets progressively more infrared-suppressed, with a\nclear turnover in momentum at all nonzero temperatures considered. Our data\nallow us to associate what was previously seen as a peak in the infrared value\nof DL(p) at Tc to severe finite-size effects along the temperature direction.\nIn particular, a temporal lattice extent Nt >= 8 seems to be needed to study\nthe electric sector around the transition. Once these systematic errors are\neliminated, the infrared behavior of the longitudinal propagator appears to be\nrather independent of the temperature below the transition. Above Tc, the\ninfrared value of DL(p) starts to decrease monotonically with the temperature."
    },
    {
        "anchor": "The vector meson mass in the large N limit of QCD: The vector meson mass is computed as a function of quark mass in the large N\nlimit of QCD. We use continuum reduction and directly compute the vector meson\npropagator in momentum space. Quark momentum is inserted using the quenched\nmomentum prescription.",
        "positive": "Initial guesses for multi-shift solvers: I will present a method for providing initial guesses to a linear solver for\nsystems with multiple shifts. This can also be extended to the case of multiple\nsources each with a different shift."
    },
    {
        "anchor": "D-meson decay constants and a check of factorization in non-leptonic\n  B-decays: We compute the vector meson decay constants fD*, fDs* from the simulation of\ntwisted mass QCD on the lattice with Nf = 2 dynamical quarks. When combining\ntheir values with the pseudoscalar D(s)-meson decay constants, we were able (i)\nto show that the heavy quark spin symmetry breaking effects with the charm\nquark are large, fDs*/fDs = 1.26(3), and (ii) to check the factorization\napproximation in a few specific B-meson non-leptonic decay modes. Besides our\nmain results, fD* = 278 \\pm 13 \\pm 10 MeV, and fDs* = 311 \\pm 9 MeV, other\nphenomenologically interesting results of this paper are: fDs*/fD* = 1.16 \\pm\n0.02 \\pm 0.06, fDs*/fD = 1.46 \\pm 0.05 \\pm 0.06, and fDs/fD* = 0.89 \\pm 0.02\n\\pm 0.03. Finally, we correct the value for B(B0 \\rightarrow D+ pi-) quoted by\nPDG, and find B(B0 \\rightarrow D+ pi-) = (7.8 \\pm 1.4) \\times 10-7.\nAlternatively, by using the ratios discussed in this paper, we obtain B(B0\n\\rightarrow D+ pi-) = (8.3 \\pm 1.0 \\pm 0.8)\\times10-7.",
        "positive": "Quark flavor physics with lattice QCD: This is an overview of quark flavor physics as presented in a plenary talk at\nLattice 2023. In the first part, I discuss the main processes and lattice-QCD\ninputs used to determine the Wolfenstein parameters of the\nCabibbo-Kobayashi-Maskawa matrix. In the second part, I review selected further\nprocesses that are being used to search for physics beyond the Standard Model.\nNew results presented at Lattice 2023 are referenced throughout, but detailed\ndiscussions are limited to selected work published prior to the conference. QED\ncorrections, inclusive decays on the lattice, and processes involving hadronic\nresonances are not discussed in detail here, as they were covered in other\nplenary talks at Lattice 2023 and Lattice 2022."
    },
    {
        "anchor": "Lattice QCD thermodynamics at finite chemical potential and its\n  comparison with Experiments: We compare higher moments of baryon numbers measured at the RHIC heavy ion\ncollision experiments with those by the lattice QCD calculations. We employ the\ncanonical approach, in which we can access the real chemical potential regions\navoiding the sign problem. In the lattice QCD simulations, we study several\nfits of the number density in the pure imaginary chemical potential, and\nanalyze how these fits affects behaviors at the real chemical potential. In the\nenergy regions between $\\sqrt{s}_{NN}$=19.6 and 200 GeV, the susceptibility\ncalculated at $T/T_c=0.93$ is consistent with experimental data at $0 \\le\n\\mu_B/T < 1.5$, while the kurtosis shows similar behavior with that of the\nexperimental data in the small $\\mu_B/T$ regions $0 \\le \\mu_B/T < 0.3$. The\nexperimental data at $\\sqrt{s}_{NN}=$ 11.5 shows quite different behavior. The\nlattice result in the deconfinement region,$T/T_c=1.35$, is far from\nexperimental data.",
        "positive": "Continuum limit and universality of the Columbia plot: Results on the thermal transition of QCD with 3 degenerate flavors, in the\nlower-left corner of the Columbia plot, are puzzling. The transition is\nexpected to be first-order for massless quarks, and to remain so for a range of\nquark masses until it turns second-order at a critical quark mass. But this\ncritical quark mass and resulting \"pion\" mass disagree violently between Wilson\nand staggered fermions at finite lattice spacing, and decrease sharply with the\nlattice spacing, for staggered fermions at least. To clarify this puzzle and\neliminate potential systematic effects from rooting, we study the 4-flavor\ntheory with staggered fermions, on lattices with 4 to 10 time-slices. Our\nresults are qualitatively similar to the 3-flavor case, so that rooting is not\nan issue. However, dramatic cutoff effects are visible, even on our finest\nlattices. Universality implies that cutoff effects for Wilson fermions are even\nmore dramatic. In order to obtain a first-order thermal transition in the\ncontinuum theory, extremely light quarks are needed."
    },
    {
        "anchor": "Monte Carlo simulation of abelian gauge-Higgs lattice models using dual\n  representation: We study abelian gauge-Higgs models on the lattice and consider gauge groups\nZ(3) and U(1). For both cases the partition sums are mapped exactly to a dual\nrepresentation where the degrees of freedom are surfaces for the gauge fields\nand loops of flux that may serve as boundaries for the surfaces represent the\nmatter fields. Also at finite chemical potential the dual partition sums have\nonly real and positive contributions and the complex action problem of the\nconventional representation is overcome in the dual approach. We apply a local\nMetropolis update for the dual degrees of freedom, as well as a generalization\nof the worm algorithm to bounded surfaces. Results that illustrate condensation\nphenomena as a function of chemical potential are discussed.",
        "positive": "Hadronic spectrum calculations in the quark-gluon plasma: A status report on FASTSUM's programme of computing spectral quantities in\nthermal QCD, using anisotropic lattice simulations with $N_f=2+1$ flavours of\nWilson fermions, is given. We provide in particular some details of the next\ngeneration of ensembles, which is currently being finalised, and give\npreliminary results for susceptibilities and baryonic correlators on those\nensembles."
    },
    {
        "anchor": "QCD with domain wall quarks: We present lattice calculations in QCD using a variant of Kaplan fermions\nwhich retain the continuum SU(N)xSU(N) chiral symmetry on the lattice in the\nlimit of an infinite extra dimension. In particular, we show that the pion mass\nand the four quark matrix element related to K_0-K_0-bar mixing have the\nexpected behavior in the chiral limit, even on lattices with modest extent in\nthe extra dimension, e.g. N_s=10.",
        "positive": "Towards Four-Flavour Dynamical Simulations: The inclusion of physical effects from sea quarks has been one of the main\nadvances in lattice QCD simulations over the last few years. We report on\nrecent studies with four flavours of dynamical quarks and address some of the\npotential issues arising in this new setup. First results for physical\nobservables in the light, strange and charm sectors are presented together with\nthe status of dedicated simulations to perform the non-perturbative\nrenormalisation in mass-independent schemes."
    },
    {
        "anchor": "Exceptional thermodynamics: The equation of state of G(2) gauge theory: We present a lattice study of the equation of state in Yang-Mills theory\nbased on the exceptional G(2) gauge group. As is well-known, at zero\ntemperature this theory shares many qualitative features with real-world QCD,\nincluding the absence of colored states in the spectrum and dynamical string\nbreaking at large distances. In agreement with previous works, we show that at\nfinite temperature this theory features a first-order deconfining phase\ntransition, whose nature can be studied by a semi-classical computation. We\nalso show that the equilibrium thermodynamic observables in the deconfined\nphase bear striking quantitative similarities with those found in SU(N) gauge\ntheories: in particular, these quantities exhibit nearly perfect\nproportionality to the number of gluon degrees of freedom, and the trace\nanomaly reveals a characteristic quadratic dependence on the temperature, also\nobserved in SU(N) Yang-Mills theories (both in four and in three spacetime\ndimensions). We compare our lattice data with analytical predictions from\neffective models, and discuss their implications for the deconfinement\nmechanism and high-temperature properties of strongly interacting,\nnon-supersymmetric gauge theories. Our results give strong evidence for the\nconjecture that the thermal deconfining transition is governed by a universal\nmechanism, common to all simple gauge groups.",
        "positive": "Hosotani mechanism on the lattice: We explore the phase structure and symmetry breaking in four-dimensional\nSU(3) gauge theory with one spatial compact dimension on the lattice in the\npresence of fermions in the adjoint and fundamental representations with\ngeneral boundary conditions. The eigenvalue phases of Polyakov loops and the\nassociated susceptibility are measured on 16^3 x 4 lattice. We establish a\ncorrespondence between the phases found on the lattice and the gauge symmetry\nbreaking by the Hosotani mechanism."
    },
    {
        "anchor": "String breaking and lines of constant physics in the SU(2) Higgs model: We present results for the ground state and first excited state static\npotentials in the confinement \"phase\" of the SU(2) Higgs model. String breaking\nand the crossing of the energy levels are clearly visible. We address the\nquestion of the cut-off effects in our results and observe a remarkable scaling\nof the static potentials.",
        "positive": "A Method for Simulating Chiral Fermions on the Lattice: A method for simulating chiral gauge theories on the lattice is proposed,\ninvolving zeromodes on a topological defect. Lattice doublers may be decoupled\nin a gauge invariant manner, and flavor anomalies can be directly observed on a\nfinite lattice. (Requires harvmac)"
    },
    {
        "anchor": "A Solution to the 1+1D Gauged Chiral Fermion Problem: We show that the 3450 U(1) chiral fermion theory can appear as the low energy\neffective field theory of a 1+1D local lattice model, with an on-site U(1)\nsymmetry and finite-range interactions. The on-site U(1) symmetry means that\nthe U(1) symmetry can be gauged (gaugeable for both background probe and\ndynamical fields), which leads to a non-perturbative definition of chiral gauge\ntheory --- a chiral fermion theory coupled to U(1) gauge theory. Our\nconstruction can be generalized to regularize any U(1)-anomaly-free 1+1D gauged\nchiral fermion theory with a zero chiral central charge (thus no gravitational\nanomaly) by a lattice, thanks to the recently proven \"Poincar\\'e dual\"\nequivalence between the U(1) 't Hooft anomaly free condition and the U(1)\nsymmetric interaction gapping rule, via a bosonization-fermionization\ntechnique.",
        "positive": "Random matrix analysis of the QCD sign problem: The severity of the sign problem in lattice QCD at nonzero baryon density is\nmeasured by the average phase of the fermion determinant. Motivated by the\nequivalence of chiral random matrix theory and QCD to leading order in the\nepsilon regime, we compute the phase of the fermion determinant for general\ntopology in random matrix theory as a function of the quark chemical potential\nand the quark mass. We find that the sign problem becomes milder with\nincreasing topological charge. The analytic predictions are verified by\ndetailed numerical random matrix simulations."
    },
    {
        "anchor": "Improved analysis of the scalar and vector form factors of kaon\n  semileptonic decays with N_f = 2 twisted-mass fermions: We investigate the vector and scalar form factors relevant for K_{\\ell 3}\nsemileptonic decays using maximally twisted-mass fermions with two flavors of\ndynamical quarks (N_f = 2). The simulations cover pion masses as light as 260\nMeV and four values of the lattice spacing, ranging from ~0.05 up to ~0.1 fm,\nwhich allow to compute directly, for the first time, the continuum limit for\nthe vector form factor at zero-momentum transfer, f_+(0). The preliminary\nresult is f_+(0) = 0.9544(68), where the error is statistical only. We also\nextrapolate both form factors to the physical point and study their momentum\ndependence. Our results are in good agreement with those obtained from a\ndispersion analyses of the experimental data. Together with the form factors,\nwe analyze the ratio of the leptonic decay constants f_K / f_\\pi, by imposing\nthe constraint coming from the Callan-Treiman theorem, obtaining at the\nphysical point f_K / f_\\pi = 1.190(8). Combining our results for f_+(0) and f_K\n/ f_\\pi with the experimental measurements of the leptonic and semilpetonic\ndecay rates, and using the determination of |V_{ud}| from nuclear beta decays,\nwe determine the values of the Cabibbo angle |V_{us}| from both K_{\\ell 3} and\nK_{\\ell 2} decays, obtaining |V_{us}|^{K_{\\ell 3}} = 0.2266(17) and\n$|V_{us}|^{K_{\\ell 2}} = 0.2258(16).",
        "positive": "Color Screening and Quark-Quark Interactions in Finite Temperature QCD: We analyze the screening of static diquark sources in 2-flavor QCD and\ncompare results with the screening of static quark-antiquark pairs. We show\nthat a two quark system in a fixed color representations is screened at short\ndistances like a single quark source in the same color representation whereas\nat large distances the two quarks are screened independently. At high\ntemperatures we observe that the relative strength of the interaction in\ndiquark and quark-antiquark systems, respectively, obeys Casimir scaling. We\nuse this result to examine the possible existence of heavy quark-quark bound\nstates in the high temperature phase of QCD. We find support for the existence\nof $bb$ states up to about $2T_c$ while $cc$ states are unlikely to be formed\nabove $T_c$."
    },
    {
        "anchor": "Revisiting the pion's scalar form factor in chiral perturbation theory: The quark-connected and the quark-disconnected Wick contractions contributing\nto the pion's scalar form factor are computed in the two and in the three\nflavour chiral effective theory at next-to-leading order. While the\nquark-disconnected contribution to the form factor itself turns out to be\npower-counting suppressed its contribution to the scalar radius is of the same\norder of magnitude as the one of the quark-connected contribution. This result\nunderlines that neglecting quark-disconnected contributions in simulations of\nlattice QCD can cause significant systematic effects. The technique used to\nderive these predictions can be applied to a large class of observables\nrelevant for QCD-phenomenology.",
        "positive": "Effects of the low lying Dirac modes on excited hadrons in lattice QCD: Chiral symmetry breaking in Quantum Chromodynamics is associated with the low\nlying spectral modes of the Dirac operator according to the Banks-Casher\nrelation. Here we study how removal of a variable number of low lying modes\nfrom the valence quark sector affects the masses of the ground states and first\nexcited states of baryons and mesons in two flavor lattice QCD."
    },
    {
        "anchor": "The axial anomaly of Ginsparg-Wilson fermion: The axial anomaly of Ginsparg-Wilson fermion operator $D$ is discussed in\ngeneral for the operator $R$ which enters the chiral symmetry breaking part in\nthe Ginsparg-Wilson relation. The axial anomaly and the index of $D$ as well as\nthe exact realization of the Atiyah-Singer index theorem on the lattice are\ndetermined solely by the topological characteristics of the chirally symmetric\noperator $D_c$ in the chiral limit $ R \\to 0 $.",
        "positive": "Finite ma Errors of the Overlap Fermion: In this talk, we shall assess the finite ma errors from the overlap fermion.\nWe shall present results on the speed of light from the dispersion relation and\nhyperfine splitting between the vector and pseudoscalar mesons as a function to\nma to reveal the m\\Lambda_{QCD}a^2 and m^2a^2 errors. We conclude from this\nstudy that one should be limited to using ma less than 0.5 in order to keep the\nsystematic ma errors below a few percent level."
    },
    {
        "anchor": "Three-particle Lellouch-L\u00fcscher formalism in moving frames: A manifestly relativistic-invariant Lellouch-L\\\"uscher formalism for the\nthree-particle decays is proposed. Similarly to ref.[1], the formalism is based\non the use of the non-relativistic effective Lagrangians. Manifest Lorentz\ninvariance is guaranteed, as in ref.[2], by choosing the quantization axis\nalong the total four-momentum of the three-particle system. A systematic\ninclusion of the higher-order derivative couplings, as well as higher partial\nwaves is addressed.",
        "positive": "String tensions and deconfinement transition in the SU(4) center vortex\n  model: A center vortex model for the infrared sector of SU(4) Yang-Mills theory is\nconstructed such as to reproduce both the ratio between the zero-temperature\nquark and diquark string tensions known from lattice Yang-Mills theory, as well\nas the properties of the deconfinement transition. On this basis, the\ntemperature dependence of the spatial quark and diquark string tensions is\npredicted. Though still phenomenologically viable, details of the construction\nof the SU(4) center vortex model corroborate previous arguments that modeling\ninfrared Yang-Mills dynamics purely in terms of vortex world-surface\ncharacteristics may become less appropriate as the number of colors is\nincreased."
    },
    {
        "anchor": "Domain Wall Fermion Study of Scaling in Non-perturbative Renormalization\n  of Quark Bilinears and $B_K$: We compute non--perturbatively the renormalization coefficients of scalar and\npseudoscalar operators, local vector and axial currents, conserved vector and\naxial currents, and $O_{LL}^{\\Delta S=2}$ over a wide range of energy scales\nusing a scaling technique that connects the results of simulations at different\nvalues of coupling $\\beta$. We use the domain wall fermion formulation in the\nquenched approximation at a series of three values of $\\beta, 6.0, 6.45, 7.05$\ncorresponding to lattice spacing scaling by factors of two.",
        "positive": "The torelon spectrum and the world-sheet axion: We present a major update on the spectrum of the closed flux-tube (torelon)\nin $D=3+1$ $SU(N)$ gauge theories. Namely, we calculate the excitation spectrum\nof a confining flux-tube which winds around a spatial torus as a function of\nits length $l$, for short as well as long tubes. We do so for $N=3,5,6$ and two\ndifferent values of the lattice spacing. Our states are characterised by the\nquantum numbers of spin $J$, transverse parity $P_{\\perp}$, longitudinal parity\n$P_{\\parallel}$ as well as by the longitudinal momentum $p_{\\parallel}$. Our\nextended basis of operators used in combination with the generalized eigenvalue\nmethod enables us to extract masses for all irreducible representations\ncharacterised by $\\{ |J|,P_{\\perp},P_{\\parallel} \\}$. We confirm that most of\nthe low-lying states are well described by the spectrum of the\nGoddard-Goldstone-Rebbi-Thorn string. In addition we provide strong evidence,\nthat in addition to string like states, massive modes exist on the world-sheet.\nMore precisely the ground state with quantum numbers ${|J|}^{P_{\\perp},\nP_{\\parallel}}=0^{--}$ exhibits a behaviour which is in agreement with the\ninterpretation of being an axion on the world-sheet of the flux-tube. This\nstate arises from a topological interaction term included in the effective\nworld-sheet action. In addition we observe that the second excited state with\n${|J|}^{P_{\\perp}, P_{\\parallel}}=0^{++}$ behaves as a massive mode with mass\ntwice that of the axion."
    },
    {
        "anchor": "High precision applications of lattice gauge theories in the quest for\n  new physics: We present some aspects of high precision calculations in the context of\nLattice Quantum Field Theory. This work is a collection of three studies done\nduring my Ph.D. period. First we present how to use the reweighting technique\nto compensate for the breaking of unitarity due to the use of different\nboundary conditions in the valence and sea sector. In particular when twisted\nboundary conditions are employed, with $\\theta$ twisting angle. In large volume\nwe found that the breaking is negligible, while in rather small volumes an\neffect is present. The quark mass appears to change with $\\theta$ as a cutoff\neffect. In the second part of the dissertation we present an optimization\nmethod for Hybrid Monte Carlo performances. The work is based on the existence\nof a shadow Hamiltonian, an exactly conserved quantity along the Molecular\nDynamics trajectory. The optimization method is economic since it only requires\nthe forces to be measured, which are already used for the evolution from one\nconfiguration to the new one. We found predictions for the cost of the\nsimulations with an accuracy of 10% and we could estimate the optimal\nparameters for the Omelyan integrator with mass-preconditioning and multi\ntime-scale. In the last part of the work we address the calculation of\nelectromagnetic corrections to the hadronic contribution to the $(g-2)$ anomaly\nof the muon. A long standing discrepancy between theoretical calculations and\nexperimental results is present. But before invoking New Physics we need to\nclear the sight from possible effects within the Standard Model. In this\nexploratory study we carefully matched the masses of the charged pions in the\ntheory with and without QED. We found a visible effect at the percent level\nalthough consistent with zero within two sigmas.",
        "positive": "The equation of state for two flavor QCD at N_t=6: We calculate the two flavor equation of state for QCD on lattices with\nlattice spacing a=(6T)^{-1} and find that cutoff effects are substantially\nreduced compared to an earlier study using a=(4T)^{-1}. However, it is likely\nthat significant cutoff effects remain. We fit the lattice data to expected\nforms of the free energy density for a second order phase transition at\nzero-quark-mass, which allows us to extrapolate the equation of state to m_q=0\nand to extract the speed of sound. We find that the equation of state depends\nweakly on the quark mass for small quark mass."
    },
    {
        "anchor": "The PMS project: Poor Man's Supercomputer: We briefly describe the Poor Man's Supercomputer (PMS) project carried out at\nEotvos University, Budapest. The goal was to develop a cost effective,\nscalable, fast parallel computer to perform numerical calculations of physical\nproblems that can be implemented on a lattice with nearest neighbour\ninteractions. To this end we developed the PMS architecture using PC components\nand designed a special, low cost communication hardware and the driver software\nfor Linux OS. Our first implementation of PMS includes 32 nodes (PMS1). The\nperformance of PMS1 was tested by Lattice Gauge Theory simulations. Using SU(3)\npure gauge theory or bosonic MSSM on PMS1 we obtained 3$/Mflop and 0.45$Mflop\nprice-to-sustained performance for double and single precision operations,\nrespectively. The design of the special hardware and the communication driver\nare freely available upon request for non-profit organizations.",
        "positive": "Electromagnetic vertex function of the pion at T > 0: The matrix element of the electromagnetic current between pion states is\ncalculated in quenched lattice QCD at a temperature of $T = 0.93 T_c$. The\nnonperturbatively improved Sheikholeslami-Wohlert action is used together with\nthe corresponding ${\\cal O}(a)$ improved vector current. The electromagnetic\nvertex function is extracted for pion masses down to $360 {\\rm MeV}$ and\nmomentum transfers $Q^2 \\le 2.7 {\\rm GeV}^2$."
    },
    {
        "anchor": "A New Solution to Ginsparg-Wilson Relation from Generalized Staggered\n  Fermion: A generalized anti-hermitian staggered Dirac operator is formulated. Its\nrelation with noncommutative geometry is briefly reviewed. Once this\nanti-hermitian operator is modified to be ``$\\gamma^5$-hermitian'', it will\nprovide a new solution to Ginsparg-Wilson relation, basing on an abstract\nalgebraic analysis of Neuberger's overlap construction and a redefinition of\nchirality.",
        "positive": "Mass and isovector matrix elements of the nucleon at zero-momentum\n  transfer: We present the current status of our analysis of nucleon structure\nobservables including isovector charges and twist-2 matrix elements as well as\nthe nucleon mass. Results are computed on a large set of CLS $N_f=2+1$ gauge\nensembles with $M_\\pi\\approx0.130\\mathrm{MeV}\\ldots 350\\mathrm{MeV}$, four\nvalues of the lattice spacing $a=0.05\\mathrm{fm}\\ldots 0.09\\mathrm{fm}$ and\ncovering a large range of physical volumes. Compared to the results presented\nat last year's conference we have added data on a very fine and large box at\nsmall light quark mass ($T\\times L^3=192 \\times 96^3$, $M_\\pi=172\\mathrm{MeV}$,\n$a=0.05\\mathrm{fm}$). Additional (intermediate) source-sink separations have\nbeen computed on the coarser ensembles, further increasing effective statistics\nand allowing for a more fine-grained control in the treatment of the\nexcited-state contamination. Excited states in the nucleon matrix elements are\ntamed by a simultaneous, two-state fit ansatz using the summation method."
    },
    {
        "anchor": "On the conformal anomaly of k-strings: We discuss the long distance behaviour of the flux tube associated to baryon\nvertices and argue that, if the gauge system admits stable k-strings, the\nconformal field theory describing this string in the IR has conformal anomaly\nc=(d-2)\\sigma_k/\\sigma, where \\sigma_k is the k-string tension and \\sigma that\nof the fundamental representation. We check this result in a 3D Z_4 gauge model\nat finite temperature, where a string effect directly related to \"c\" can be\nclearly identified.",
        "positive": "Analysis of saddle-point configurations in 3-dimensional SU(2) gauge\n  theory: We discuss the properties of a class of saddle point solutions in SU(2) in\nthree dimensions (SU$(2)_3$), exhibiting localized peaks in the action. These\nconfigurations are generated by deterministic cooling and extremizing\nalgorithms from analytic configurations. They share some characteristics with\ncooled and extremized Monte Carlo generated lattices. We have investigated\nphysical behavior such as the string tension by averaging over this class of\nsaddle point configurations. We have also measured the eigenvalues for harmonic\nfluctuations around these configurations."
    },
    {
        "anchor": "Charmed Hadron Interactions: We compute the scattering lengths of charmed mesons and charmonia scattering\nwith light hadrons in full QCD. We use Fermilab formulation for the charm quark\nand domain-wall fermions for the light quarks and staggered sea quarks. Four\ndifferent light-quark masses are used to extrapolate to the physical point. The\ncharmed baryon spectrum is also presented.",
        "positive": "Quark masses and decay constants in $N_f=2+1+1$ isoQCD with Wilson\n  clover twisted mass fermions: We present a preliminary study of the pion, kaon and D-meson masses and decay\nconstants in isosymmetric QCD, as well as a preliminary result for the\nlight-quark renormalized mass. The analysis is based on the gauge ensembles\nproduced by ETMC with $N_f=2+1+1$ flavours of Wilson-clover twisted mass\nquarks, spanning a range of lattice spacings from $\\sim0.10$ to $0.07$ fm and\ninclude configurations at the physical pion point on lattices with linear size\nup to $L~\\sim~5.6$~fm"
    },
    {
        "anchor": "Light Quark Mass Reweighting: We present a systematic study of the effectiveness of light quark mass\nreweighting. This method allows a single lattice QCD ensemble, generated with a\nspecific value of the dynamical light quark mass, to be used to determine\nresults for other, nearby light dynamical quark masses. We study two gauge\nfield ensembles generated with 2+1 flavors of dynamical domain wall fermions\nwith light quark masses m_l=0.02 (m_\\pi=620 MeV) and m_l=0.01 (m_\\pi=420 MeV).\nWe reweight each ensemble to determine results which could be computed directly\nfrom the other and check the consistency of the reweighted results with the\ndirect results. The large difference between the 0.02 and 0.01 light quark\nmasses suggests that this is an aggressive application of reweighting as can be\nseen from fluctuations in the magnitude of the reweighting factor by four\norders of magnitude. Never-the-less, a comparison of the reweighed topological\ncharge, average plaquette, residual mass, pion mass, pion decay constant, and\nscalar correlator between these two ensembles shows agreement well described by\nthe statistical errors. The issues of the effective number of configurations\nand finite sample size bias are discussed. An examination of the topological\ncharge distribution implies that it is more favorable to reweight from heavier\nmass to lighter quark mass.",
        "positive": "Electromagnetic structure of charmed baryons in Lattice QCD: As a continuation of our recent work on the electromagnetic properties of the\ndoubly charmed $\\Xi_{cc}$ baryon, we compute the charge radii and the magnetic\nmoments of the singly charmed $\\Sigma_c$, $\\Omega_c$ and the doubly charmed\n$\\Omega_{cc}$ baryons in 2+1 flavor Lattice QCD. In general, the charmed\nbaryons are found to be compact as compared to the proton. The charm quark acts\nto decrease the size of the baryons to smaller values. We discuss the mechanism\nbehind the dependence of the charge radii on the light valence- and sea-quark\nmasses. The magnetic moments are found to be almost stable with respect to\nchanging quark mass. We investigate the individual quark sector contributions\nto the charge radii and the magnetic moments. The magnetic moments of the\nsingly charmed baryons are found to be dominantly determined by the light quark\nand the role of the charm quark is significantly enhanced for the doubly\ncharmed baryons."
    },
    {
        "anchor": "Convergence of the chiral expansion for the nucleon mass: A number of papers recently have used fourth-order chiral perturbation theory\nto extrapolate lattice data for the nucleon mass; the process seems\nsurprisingly successful even for large pion masses. This paper shows that the\ninclusion of the fifth-order terms spoils the agreement.",
        "positive": "Towards symmetric discretization schemes via weak boundary conditions: The Szymanzik improvement program for gauge theories is most commonly\nimplemented using forward finite difference corrections to the Wilson action.\nCentral symmetric schemes naively applied, suffer from a doubling of degrees of\nfreedom, identical to the well known fermion doubling phenomenon. And while\nadding a complex Wilson term remedies the problem for fermions, it does not\neasily transfer to real-valued gauge fields. In this talk I report on recent\nprogress in formulating symmetric discretization schemes for classical actions\nof simple one-dimensional problems. They avoid doubling by exploiting the weak\nimposition of initial/boundary conditions. Inspired by recent work in the field\nof numerical analysis of partial differential equations, I construct a\nregularized summation-by-parts finite difference operator using boundary data\nbased on affine coordinates. Application to a classical initial value problems\nwith second order derivatives are presented."
    },
    {
        "anchor": "Application of the Lefschetz thimble formulation to the (0+1) dim.\n  Thirring model at finite density: Based on the Lefschetz thimble formulation of path-integration, we analyze\nthe (0+1) dimensional Thirring model at finite chemical potentials and perform\nhybrid Monte Carlo (HMC) simulations. We adopt the lattice action defined with\nthe staggered fermion and a compact link field for the auxiliary vector field.\nWe firstly locate the critical points (saddle points) of the gradient flows\nwithin the subspace of time-independent (complex) link field, and study the\nthiemble structure and the Stokes phenomenon to identify the thimbles which\ncontribute to the path-integral. Then, we perform HMC simulations on the single\ndominant thimble and compare the results to the exact solution. The numerical\nresults are in agreement with the exact ones in small and large chemical\npotential regions, while they show some deviation in the crossover region in\nthe chemical potential. We also comment on the necessity of the contributions\nfrom multiple thimbles in the crossover region.",
        "positive": "Grassmann tensor-network method for strong-coupling QCD: We present a tensor-network method for strong-coupling QCD with staggered\nquarks at nonzero chemical potential. After integrating out the gauge fields at\ninfinite coupling, the partition function can be written as a full contraction\nof a tensor network consisting of coupled local numeric and Grassmann tensors.\nTo evaluate the partition function and to compute observables, we develop a\nGrassmann higher-order tensor renormalization group method, specifically\ntailored for this model. We apply the method to the two-dimensional case and\nvalidate it by comparing results for the partition function, the chiral\ncondensate and the baryon density with exact analytical expressions on small\nlattices up to volumes of $4\\times4$. For larger two-dimensional volumes, we\npresent tensor results for the chiral condensate as a function of the mass and\nvolume, and observe that the chiral symmetry is not broken dynamically in two\ndimensions. Furthermore, our results for the number density as a function of\nthe chemical potential hint at a first-order phase transition. Finally, we\npresent some preliminary tensor results for three-dimensional strong-coupling\nQCD."
    },
    {
        "anchor": "The lattice SU(2) confining string as an Abrikosov vortex: Numerical data for the SU(2) confining string in the maximal abelian\nprojection are analysed. The distribution of the electric flux and monopole\ncurrents are perfectly described by the classical equations of motion for the\ndual Abelian Higgs model. The mass of the vector boson is equal to the mass of\nthe monopole (Higgs particle) within numerical errors. The classical energy per\nunit length of the Abrikosov vortex reproduces 94% of the full non-Abelian\nstring tension.",
        "positive": "Topology and metastability in the lattice Skyrme model: We offer the Skyrme model on a lattice as an effective field theory - fully\nquantized - of baryon-meson interactions at temperatures below the chiral phase\ntransition. We define a local topological density that involves the volumes of\ntetrahedra in the target space S^3 and we make use of Coxeter's formula for the\nSchlafli function to implement it. This permits us to calculate the mean-square\nradius of a skyrmion in the three-dimensional lattice Skyrme model, which may\nbe viewed as a Ginzburg-Landau effective theory for the full quantum theory at\nfinite temperature. We find that, contrary to expectations, the skyrmion\nshrinks as quantum and thermal fluctuations are enhanced. We ascribe this to a\nlarge number of metastable states that become accessible as the temperature is\nraised."
    },
    {
        "anchor": "The twisted gradient flow running coupling in SU(3): a non-perturbative\n  determination: We report some preliminary results of our ongoing non-perturbative\ncomputation of the twisted 't Hooft running coupling in a particular set-up,\nusing the gradient flow to define the coupling and step scaling techniques to\ncompute it. For the computation we considered a pure gauge SU(3) theory in four\ndimensions, defined on the lattice on an asymmetrical torus endowed with\ntwisted boundary conditions in a single plane, and related the energy scale of\nthe coupling to an effective size combining the size of the torus and the rank\nof the gauge group. Additionally, we explore some of the effects of the\nfreezing of the topology on the computation of the coupling.",
        "positive": "Simulating chiral quarks in the epsilon-regime of QCD: We present simulation results for lattice QCD with chiral fermions in small\nvolumes, where the epsilon-expansion of chiral perturbation theory applies. Our\ndata for the low lying Dirac eigenvalues, as well as mesonic correlation\nfunctions, are in agreement with analytical predictions. This allows us to\nextract values for the leading Low Energy Constants F_{pi} and Sigma."
    },
    {
        "anchor": "Axial Nucleon to Delta transition form factors on 2+1 flavor hybrid\n  lattices: We correct the values of the dominant nucleon to Delta axial transition form\nfactors CA_5 and CA_6 published in C. Alexandrou et.al., Phys. Rev. D 76,094511\n(2007). The analysis error affects only the values obtained when using the\nhybrid action in the low Q^2 regime bringing them into agreement with those\nobtained with Wilson fermions.",
        "positive": "Evidence that center vortices drive dynamical mass generation in QCD: The first calculation of the response of the momentum space quark propagator\nto center vortices in the ground state fields of QCD is presented. Center\nvortices are identified on 2+1-flavour dynamical gauge fields with $m_\\pi\n\\simeq 156$ MeV to obtain the vortex-removed and vortex-only quark propagator.\nDynamical mass generation is found to vanish upon vortex removal, while the\nvortex-only field is able to generate dynamical mass. These new signatures\nsignificantly strengthen evidence that center vortices underpin both dynamical\nchiral symmetry breaking and quark confinement."
    },
    {
        "anchor": "Measurements of $SU(3)_f$ symmetry breaking in $B$ meson decay constants: We present updates from QCDSF/UKQCD/CSSM on the $SU(3)_f$ breaking in $B$\nmeson decay constants. The $b$-quarks are generated with an anisotropic\nclover-improved action, and are tuned to match properties of the physical $B$\nand $B^*$ mesons. Configurations are generated with\n$\\overline{m}=(1/3)(2m_l+m_s)$ kept constant to control symmetry breaking\neffects. Various sources of systematic uncertainty will be discussed, including\nthose from continuum extrapolations and extrapolations to the physical point.\nWe also present new efforts to calculate $f_B$ and $f_{B_s}$ using weighted\naverages across multiple time fitting regions. The use of an automated weighted\naveraging technique over multiple fitting ranges allows for timely tuning of\nthe $b$-quark and reduces the impact of systematic errors from fitting range\nbiases in calculations of $f_B$ and $f_{B_s}$",
        "positive": "A Noisy Monte Carlo Algorithm: We propose a Monte Carlo algorithm to promote Kennedy and Kuti's linear\naccept/reject algorithm which accommodates unbiased stochastic estimates of the\nprobability to an exact one. This is achieved by adopting the Metropolis\naccept/reject steps for both the dynamical and noise configurations. We test it\non the five state model and obtain desirable results even for the case with\nlarge noise. We also discuss its application to lattice QCD with stochastically\nestimated fermion determinants."
    },
    {
        "anchor": "Susceptibility of the QCD vacuum to CP-odd electromagnetic background\n  fields: We investigate two flavor QCD in presence of CP-odd electromagnetic\nbackground fields and determine, by means of lattice QCD simulations, the\ninduced effective theta term to the first order in the scalar product of E and\nB. We employ a rooted staggered discretization and study lattice spacings down\nto 0.1 fm and Goldstone pion masses around 480 MeV. In order to deal with a\npositive measure, we consider purely imaginary electric fields and real\nmagnetic fields, then exploiting analytic continuation. Our results are\nrelevant to a description of the effective pseudoscalar QED-QCD interactions.",
        "positive": "Demons and Abelian Projection QCD: Action and Crossover: I evaluate S_{APQCD}, the exact action of Abelian projection QCD, using the\nmicrocanonical demon method. Starting with a trial action consisting of L=1,\nL=2, & L=3 LxL plaquettes plus a Smit-van-der-Sijs magnetic monopole ``mass''\noperator, I show that coefficients of the L=2 and L=3 plaquettes vanish at all\nbeta_{SU2}. In fact, at strong coupling S_{APQCD} is essentially the 1x1\ncompact QED action with beta_{U1}=beta_{SU2}/2. Beyond beta_{SU2}>=2, S_{APQCD}\ngains an exogenous negative 1x1x1 magnetic monopole mass shift. Note that my\napproach differs fundamentally from the Smit-van-der-Sijs approach in that I do\nnot make an a priori assumption about monopole or plaquette size in S_{APQCD}.\nIndeed, these results suggest that QCD monopoles are pointlike, in contrast to\nthe ``effective'' condensation picture put forth by Smit and van der Sijs."
    },
    {
        "anchor": "Scaling study for 2 HEX smeared fermions: hadron and quark masses: The goal of this study is to investigate the scaling behaviour of our 2 HEX\naction. For this purpose, we compute the $N_f=3$ spectrum and compare the\nresults to our 6 EXP action. We find a large scaling window up to $\\sim\n0.15\\,\\mathrm{fm}$ along with small scaling corrections at the 2%-level and\nfull compatibility with our previous study. As a second important observable to\nbe tested for scaling, we chose the non-perturbatively renormalized quenched\nstrange quark mass. Here we find a fairly flat scaling with a broad scaling\nrange up to $\\simeq 0.15\\,\\mathrm{fm}$ and perfect agreement with the\nliterature.",
        "positive": "Euclidean versus Minkowski short distance: In this note we reexamine the possibility of extracting parton distribution\nfunctions from lattice simulations. We discuss the case of quasi-parton\ndistribution functions, the possibility of using the reduced Ioffe-time\ndistributions and the more recent proposal of directly making reference to the\ncomputation of the current-current $T$-product. We show that in all cases the\nprocess of renormalization hindered by lattice momenta limitation represents an\nobstruction to a direct Euclidean calculation of the parton distribution\nfunction."
    },
    {
        "anchor": "Three-dimensional lattice SU($N_c$) gauge theories with multiflavor\n  scalar fields in the adjoint representation: We consider three-dimensional lattice SU($N_c$) gauge theories with\nmultiflavor ($N_f>1$) scalar fields in the adjoint representation. We\ninvestigate their phase diagram, identify the different Higgs phases with their\ngauge-symmetry pattern, and determine the nature of the transition lines. In\nparticular, we study the role played by the quartic scalar potential and by the\ngauge-group representation in determining the Higgs phases and the global and\ngauge symmetry-breaking patterns characterizing the different transitions. The\ngeneral arguments are confirmed by numerical analyses of Monte Carlo results\nfor two representative models that are expected to have qualitatively different\nphase diagrams and Higgs phases. We consider the model with $N_c = 3$, $N_f=2$\nand with $N_c=2$, $N_f= 4$. This second case is interesting phenomenologically\nto describe some features of cuprate superconductors.",
        "positive": "Fermion Bag Approach to Fermion Sign Problems: The fermion bag approach is a new method to tackle fermion sign problems in\nlattice field theories. Using this approach it is possible to solve a class of\nsign problems that seem unsolvable by traditional methods. The new solutions\nemerge when partition functions are written in terms of fermion bags and\nbosonic worldlines. In these new variables it is possible to identify hidden\npairing mechanisms which lead to the solutions. The new solutions allow us for\nthe first time to use Monte Carlo methods to solve a variety of interesting\nlattice field theories, thus creating new opportunities for understanding\nstrongly correlated fermion systems."
    },
    {
        "anchor": "Excitations of the nucleon with dynamical fermions: We measure the spectrum of low-lying nucleon resonances using Bayesian\nfitting methods. We compare the masses obtained in the quenched approximation\nto those obtained with two flavours of dynamical fermions at a matched lattice\nspacing. At the pion masses employed in our simulations, we find that the mass\nof the first positive-parity nucleon excitation is always greater than that of\nthe parity partner of the nucleon.",
        "positive": "Determination of the Delta resonance width from lattice QCD: A method suitable for extracting resonance parameters of unstable baryons in\nlattice QCD is examined. The method is applied to the strong decay of the Delta\nto a pion-nucleon state, extracting the pi-N - Delta coupling constant and\nDelta decay width."
    },
    {
        "anchor": "Non-perturbative parton mass for the gluon: A gauge invariant, non-local observable is constructed in pure gauge theory,\nwhich is identical to the gluon propagator in a particular gauge, permitting to\ndefine a non-perturbative parton mass for the gluon. This mass can be shown to\nbe related to the 1P-1S mass splitting of heavy quarkonia. Preliminary\nnumerical results for 3d SU(2) yield m_A=0.37(6)g^2, while from the \\bar{b}b\nspectrum one infers m_A\\approx 420 MeV for QCD.",
        "positive": "Defining Canonical Momenta for Discretised SU(2) Gauge Fields: In this proceeding contribution we discuss how to define canonical momenta\nfor SU(N) lattice gauge theories in the Hamiltonian formalism in a basis where\nthe gauge field operators are diagonal. For an explicit discretisation of SU(2)\nwe construct the momenta and check the violation of the fundamental commutation\nrelations."
    },
    {
        "anchor": "Large Energy Cumulants in the 2D Potts Model and their Effects in Finite\n  Size Analysis: We develop an ansatz for expressing the free energy of the two dimensional\n$q$-states Potts model for $q > 4$ near its first order phase transition point.\nWe notice that for the moderate values of $ q \\lesssim 15 $, the energy profile\nat the phase transition is not expressible as a sum of gaussians. We discuss\nhow this affects the traditional finite size analysis of this phase transition.\nIn particular, the dominant length scale governing the finite size corrections\nturns out to be much (${} \\sim 6$ ~times) larger than the largest correlation\nlength in the problem.",
        "positive": "Numerical study of hot strongly interacting matter: I review recent progress in study of strongly interacting matter at high\ntemperatures using Monte-Carlo simulations in lattice QCD."
    },
    {
        "anchor": "Scalar and axial matrix elements of the nucleon: sea quark content: Sea quark contributions to the scalar density and the axial current matrix\nelements of the nucleon are studied in lattice qcd with two flavours of\ndynamical wilson fermions. the results are compared to trends in heavy quark\nmass expansions, and contrasted with the numbers obtained using dynamical\nstaggered fermions.",
        "positive": "Majorana and Majorana-Weyl fermions in lattice gauge theory: In various dimensional Euclidean lattice gauge theories, we examine a\ncompatibility of the Majorana decomposition and the charge conjugation property\nof lattice Dirac operators. In $8n$ and $1+8n$ dimensions, we find a difficulty\nto decompose a classical lattice action of the Dirac fermion into a system of\nthe Majorana fermion and thus to obtain a factorized form of the Dirac\ndeterminant. Similarly, in $2+8n$ dimensions, there is a difficulty to\ndecompose a classical lattice action of the Weyl fermion into a system of the\nMajorana--Weyl fermion and thus to obtain a factrized form of the Weyl\ndeterminant. Prescriptions based on the overlap formalism do not remove these\ndifficulties. We argue that these difficulties are reflections of the global\ngauge anomaly associated to the real Weyl fermion in $8n$ dimensions. For this\nreason (besides other well-known reasons), a lattice formulation of the N=1\nsuper Yang--Mills theory in these dimensions is expected to be extremely\ndifficult to find."
    },
    {
        "anchor": "Matter-antimatter coexistence method for finite density QCD toward a\n  solution of the sign problem: Toward the lattice QCD calculation at finite density, we propose\n\"matter-antimatter coexistence method\", where matter and anti-matter systems\nare prepared on two parallel ${\\bf R}^4$-sheets in five-dimensional Euclidean\nspace-time. We put a matter system $M$ with a chemical potential $\\mu \\in {\\bf\nC}$ on a ${\\bf R}^4$-sheet, and also put an anti-matter system $\\bar M$ with\n$-\\mu^*$ on the other ${\\bf R}^4$-sheet shifted in the fifth direction. Between\nthe gauge variables $U_\\nu \\equiv e^{iagA_\\nu}$ in $M$ and $\\tilde U_\\nu \\equiv\ne^{iag \\tilde A_\\nu}$ in $\\bar M$, we introduce a correlation term with a real\nparameter $\\lambda$. In one limit of $\\lambda \\rightarrow \\infty$, a strong\nconstraint $\\tilde U_\\nu(x)=U_\\nu(x)$ is realized, and therefore the total\nfermionic determinant becomes real and non-negative, due to the cancellation of\nthe phase factors in $M$ and $\\bar M$, although this system resembles QCD with\nan isospin chemical potential. In another limit of $\\lambda \\rightarrow 0$,\nthis system goes to two separated ordinary QCD systems with the chemical\npotential of $\\mu$ and $-\\mu^*$. For a given finite-volume lattice, if one\ntakes an enough large value of $\\lambda$, $\\tilde U_\\nu(x) \\simeq U_\\nu(x)$ is\nrealized and phase cancellation approximately occurs between two fermionic\ndeterminants in $M$ and $\\bar M$, which suppresses the sign problem and is\nexpected to make the lattice calculation possible. For the obtained gauge\nconfigurations of the coexistence system, matter-side quantities are evaluated\nthrough their measurement only for the matter part $M$. The physical quantities\nin finite density QCD are expected to be estimated by the calculations with\ngradually decreasing $\\lambda$ and the extrapolation to $\\lambda=0$. We also\nconsider more sophisticated improvement of this method using an irrelevant-type\ncorrelation.",
        "positive": "Two-dimensional N=(2,2) super Yang-Mills theory on the lattice via\n  dimensional reduction: The N=(2,2) extended super Yang-Mills theory in 2 dimensions is formulated on\nthe lattice as a dimensional reduction of a 4 dimensional lattice gauge theory.\nWe use the plaquette action for a bosonic sector and the Wilson- or the\noverlap-Dirac operator for a fermion sector. The fermion determinant is real\nand, moreover, when the overlap-Dirac operator is used, semi-positive definite.\nThe flat directions in the target theory become compact and present no subtlety\nfor a numerical integration along these directions. Any exact supersymmetry\ndoes not exist in our lattice formulation; nevertheless we argue that one-loop\ncalculable and finite mass counter terms ensure a supersymmetric continuum\nlimit to all orders of perturbation theory."
    },
    {
        "anchor": "A new technique to incorporate multiple fermion flavors in tensor\n  renormalization group method for lattice gauge theories: We propose a new technique to incorporate multiple fermion flavors in the\ntensor renormalization group method for lattice gauge theories, where fermions\nare treated by the Grassmann tensor network formalism. The basic idea is to\nseparate the site tensor into multiple layers associated with each flavor and\nto introduce the gauge field in each layer as replicas, which are all\nidentified later. This formulation, after introducing an appropriate\ncompression scheme in the network, enables us to reduce the size of the initial\ntensor with high efficiency compared with a naive implementation. The\nusefulness of this formulation is demonstrated by investigating the chiral\nphase transition and the Silver Blaze phenomenon in 2D Abelian gauge theories\nwith $N_{\\rm f}$ flavors of Wilson fermions up to $N_{\\rm f}=4$.",
        "positive": "A massive momentum-subtraction scheme: We introduce a new massive renormalization scheme, denoted mSMOM, as a\nmodification of the existing RI/SMOM scheme. We use SMOM for defining\nrenormalized fermion bilinears in QCD at non-vanishing fermion mass. This\nscheme has properties similar to those of the SMOM scheme, such as the use of\nnon-exceptional symmetric momenta, while in contrast to SMOM, it defines the\nrenormalized fields away from the chiral limit. Here we discuss some of the\nproperties of mSMOM, and present non-perturbative arguments for deriving some\nrenormalization constants. The results of a 1-loop calculation in dimensional\nregularization are briefly summarised to illustrate some properties of the\nscheme."
    },
    {
        "anchor": "The order of the Roberge-Weiss endpoint (finite size transition) in QCD: We consider the endpoint of the Roberge-Weiss (RW) first order transition\nline present for imaginary baryon chemical potentials. We remark that it\ncoincides with the finite size transition relevant in the context of large\n$N_c$ QCD and study its order in the theory with two degenerate flavors. The RW\nendpoint is first order in the limit of large and small quark masses, while it\nweakens for intermediate masses where it is likely in the Ising 3d universality\nclass. Phenomenological implications and further speculations about the QCD\nphase diagram are discussed.",
        "positive": "When QCD strings can break: The confining string in presence of dynamical quarks can behave in different\nways, depending on the quark masses and on the number N_f N_c of charge\nspecies. For light masses and large N_f N_c the creation of quark pairs\nproduces microscopic holes in the world- sheet swept by the string; as a\nconsequence string breaking is invisible in the Wilson loop, while is manifest\nin operators composed of disjoint sources, as observed in many numerical\nexperiments. Similar arguments apply also to the adjoint string breaking. For\nlarger quark masses it is possible that the string world-sheet undergoes a\ntransition to a tearing phase, characterized by macroscopic holes, which\nmanifest themselves through a visible string breaking effect also in the Wilson\nloop, as observed in 2+1 D SU(2) gauge theory with two flavors."
    },
    {
        "anchor": "Light-cone PDFs from Lattice QCD: Using the approach proposed a few years ago by X. Ji, it has become feasible\nto extract parton distribution functions (PDFs) from lattice QCD, a task\nthought to be extremely difficult before Ji's proposal. In this talk, we\ndiscuss this approach, in particular different systematic effects that need to\nbe controlled to ultimately have precise determinations of PDFs. Special\nattention is paid to the analysis of excited states. We emphasize that it is\ncrucial to control excited states contamination and we show an analysis thereof\nfor our lattice data, used to calculate quasi-PDFs and finally light-cone PDFs\nin the second part of this proceeding (C. Alexandrou et al., Quasi-PDFs from\nTwisted mass fermions at the physical point).",
        "positive": "QCD at imaginary chemical potential with Wilson fermions: We investigate the phase diagram in the temperature, imaginary chemical\npotential plane for QCD with three degenerate quark flavors using Wilson type\nfermions. While more expensive than the staggered fermions used in past studies\nin this area, Wilson fermions can be used safely to simulate systems with three\nquark flavors. In this talk, we focus on the (pseudo)critical line that extends\nfrom $\\mu=0$ in the imaginary chemical potential plane, trace it to the\nRoberge-Weiss line, and determine its location relative to the Roberge-Weiss\ntransition point. In order to smoothly follow the (pseudo)critical line in this\nplane we perform a multi-histogram reweighting in both temperature and chemical\npotential. To perform reweighting in the chemical potential we use the\ncompression formula to compute the determinants exactly. Our results are\ncompatible with the standard scenario."
    },
    {
        "anchor": "Numerical simulation of dynamical gluinos: experience with a\n  multi-bosonic algorithm and first results: We report on our experience with the two-step multi-bosonic algorithm in a\nlarge scale Monte Carlo simulation of the SU(2) Yang-Mills theory with\ndynamical gluinos. First results are described on the low lying spectrum of\nbound states, the string tension and the gluino condensate.",
        "positive": "Spectroscopy in finite density lattice field theory: An exploratory\n  study in the relativistic Bose gas: We analyze 2-point functions in the relativistic Bose gas on the lattice,\ni.e., a charged scalar phi-4 field with chemical potential mu. Using a\ngeneralized worm algorithm we perform a Monte Carlo simulation in a dual\nrepresentation in terms of fluxes where the complex action problem is overcome.\nWe explore various aspects of lattice spectroscopy at finite density and zero\ntemperature, such as the asymmetry of forward and backward propagation in time\nand the transition into the condensed phase. It is shown that after a suitable\nsubtraction the exponents for forward and backward propagation are independent\nof mu and agree with the mass obtained from the propagator at mu = 0. This\nholds for mu < mu_c and shows that below the condensation transition the mass\nis independent of mu as expected from the Silver Blaze scenario."
    },
    {
        "anchor": "Chiral phase transition of $N_f$=2+1 QCD with the HISQ action: We present studies of universal properties of the chiral phase transition in\n$N_f$=2+1 QCD based on the simulations using Highly Improved Staggered fermions\non lattices with temporal extent $N_\\tau$=6. We analyze the quark mass and\nvolume dependence of the chiral condensates and chiral susceptibilities in QCD\nwith two degenerate light quarks and a strange quark. The strange quark mass is\nchosen to be fixed to its physical value ($m^{phy}_s$) and five values of light\nquark masses ($m_l$) that are varied in the interval 1/20$\\gtrsim m_l/m^{phy}_s\n\\gtrsim$1/80. Here various quark masses correspond to pseudo Goldstone pion\nmasses ranging from about 160 MeV to about 80 MeV. The O(N) scaling of chiral\nobservables and the influence of universal scaling on physical observables in\nthe region of physical quark mass values are also discussed.",
        "positive": "Continuum limit of lattice QCD with staggered quarks in the quenched\n  approximation - a critical role for the chiral extrapolation: We calculate the light quark spectrum of lattice QCD in the quenched\napproximation using Kogut-Susskind quarks. By combining results for different\nlattice spacings, several volumes and five quark masses, we are able to take\nthe light quark mass, infinite volume, continuum limit. When we use non-linear\nchiral extrapolations, we find that the nucleon to rho mass ratio is 1.254 +-\n0.018 +- 0.027, where the errors are statistical and systematic (within the\nquenched approximation), respectively. This should be compared with the\nexperimental value of 1.22. Our results indicate that the error due to\nquenching is less than about 5%."
    },
    {
        "anchor": "Lattice study of the chiral properties of large $N_c$ QCD: We present a lattice calculation of the low energy constants of QCD with\n$N_c=3$, 4 and 5 colors and $N_f=2$ flavors of degenerate mass fermions. We fit\ndata for the pseudoscalar meson mass, the pseudoscalar decay constant, and the\nAxial Ward Identity fermion mass to formulas from next to next to leading order\nchiral perturbation theory. We extract the next to leading order low energy\nconstants and study their behavior as a function of $N_c$. Pre-existing\nanalyses of $N_c=3$ inform our fitting strategies.",
        "positive": "Background Configurations, Confinement and Deconfinement on a Lattice\n  with BPS Monopole Boundary Conditions: Finite temperature SU(2) lattice gauge theory is investigated in a 3D cubic\nbox with fixed boundary conditions provided by a discretized, static BPS\nmonopole solution with varying core scale $\\mu$. Using heating and cooling\ntechniques we establish that for discrete $\\mu$-values stable classical\nsolutions either of self-dual or of pure magnetic type exist inside the box.\nHaving switched on quantum fluctuations we compute the Polyakov line and other\nlocal operators. For different $\\mu$ and at varying temperatures near the\ndeconfinement transition we study the influence of the boundary condition on\nthe vacuum inside the box. In contrast to the pure magnetic background field\ncase, for the self-dual one we observe confinement even for temperatures quite\nfar above the critical one."
    },
    {
        "anchor": "Magnetized baryons and the QCD phase diagram: NJL model meets the\n  lattice: We determine the baryon spectrum of 1 + 1 + 1-flavor QCD in the presence of\nstrong background magnetic fields using lattice simulations at physical quark\nmasses for the first time. Our results show a splitting within multiplets\naccording to the electric charge of the baryons and reveal, in particular, a\nreduction of the nucleon masses for strong magnetic fields. This\nfirst-principles input is used to define constituent quark masses and is\nemployed to set the free parameters of the Polyakov loop-extended\nNambu-Jona-Lasinio (PNJL) model in a magnetic field-dependent manner. The so\nconstructed model is shown to exhibit inverse magnetic catalysis at high\ntemperatures and a reduction of the transition temperature as the magnetic\nfield grows - in line with non-perturbative lattice results. This is contrary\nto the naive variant of this model, which gives incorrect results for this\nfundamental phase diagram. Our findings demonstrate that the magnetic field\ndependence of the PNJL model can be reconciled with the lattice findings in a\nsystematic way, employing solely zero-temperature first-principles input.",
        "positive": "Renormalization Group Analysis of Finite-Size Scaling in the $\u03a6^4_4$\n  Model: A finite-size scaling theory for the $\\phi^4_4$ model is derived using\nrenormalization group methods. Particular attention is paid to the partition\nfunction zeroes, in terms of which all thermodynamic observables can be\nexpressed. While the leading scaling behaviour is identical to that of mean\nfield theory, there exist multiplicative logarithmic corrections too. A\nnon-perturbative test of these formulae in the form of a high precision Monte\nCarlo analysis reveals good quantitative agreement with the analytical\npredictions."
    },
    {
        "anchor": "The nucleon isovector tensor charge from lattice QCD using chiral\n  fermions: In this work we present the isovector flavor combination for the nucleon\ntensor charge extracted from lattice QCD simulations using overlap fermions on\n$N_f=2+1$ domain-wall configurations. The pion mass dependence is studied using\nsix valence quark masses, each reproducing a value for the pion mass in the\nvalence sector between 147 and 330 MeV. We investigate and eliminate systematic\nuncertainties due to contamination by excited states, by employing several\nvalues for the source-sink separation that span from 1 fm to 1.6 fm. We apply a\nchiral extrapolation in the valence sector using a quadratic and a logarithmic\nterm to fit the pion mass dependence, which describes well the lattice data.\nThe lattice matrix element is renormalized non-perturbatively, and the final\nresult is $g_T=1.096(30)$ in the $\\overline{\\rm MS}$ scheme at a\nrenormalization scale of 2 GeV.",
        "positive": "Prediction of positive parity $B_s$ mesons and search for the $X(5568)$: We use a combination of quark-antiquark and $B^{(*)}K$ interpolating fields\nto predict the mass of two QCD bound states below the $B^*K$ threshold in the\nquantum channels $J^P=0^+$ and $1^+$. The mesons correspond to the b-quark\ncousins of the $D_{s0}^*(2317)$ and $D_{s1}(2460)$ and have not yet been\nobserved in experiment, even though they are expected to be found by LHCb. In\naddition to these predictions, we obtain excellent agreement of the remaining\np-wave energy levels with the known $B_{s1}(5830)$ and $B_{s2}^*(5840)$ mesons.\nThe results from our first principles calculation are compared to previous\nmodel-based estimates. More recently the D0 collaboration claimed the existence\nof an exotic resonance $X(5568)$ with exotic flavor content $\\bar{b}s\\bar{d}u$.\nIf such a state with $J^P=0^+$ exists, only the decay into $B_s\\pi$ is open\nwhich makes a lattice search for this state much cleaner and simpler than for\nother exotic candidates involving heavy quarks. We conclude, however, that we\ndo not find such a candidate in agreement with a recent LHCb result."
    },
    {
        "anchor": "Update on lattice QCD with domain wall quarks: Using domain wall fermions, we estimate B_K(mu approx 2 GeV)=0.602(38) in\nquenched QCD which is consistent with previous calculations. We also find\nratios of decay constants that are consistent with experiment, within our\nstatistical errors. Our initial results indicate good scaling behavior and\nsupport expectations that O(a) errors are exponentially suppressed in low\nenergy (E<< a^{-1}) observables. It is also shown that the axial current\nnumerically satisfies the lattice analog of the usual continuum axial Ward\nidentity and that the matrix element of the four quark operator needed for B_K\nexhibits excellent chiral behavior.",
        "positive": "Instantaneous Interquark Potential in Generalized Landau Gauge in SU(3)\n  Lattice QCD: A Linkage between the Landau and the Coulomb Gauges: We investigate in detail \"instantaneous interquark potentials\", interesting\ngauge-dependent quantities defined from the spatial correlators of the temporal\nlink-variable $U_4$, in generalized Landau gauge using SU(3) quenched lattice\nQCD. The instantaneous Q$\\bar{\\rm Q}$ potential has no linear part in the\nLandau gauge, and it is expressed by the Coulomb plus linear potential in the\nCoulomb gauge, where the slope is 2-3 times larger than the physical string\ntension. Using the generalized Landau gauge, we find that the instantaneous\npotential can be continuously described between the Landau and the Coulomb\ngauges, and its linear part rapidly grows in the neighborhood of the Coulomb\ngauge. We also investigate the instantaneous 3Q potential in the generalized\nLandau gauge, and obtain similar results to the Q$\\bar{\\rm Q}$ case. $T$-length\nterminated Polyakov-line correlators and their corresponding \"finite-time\npotentials\" are also investigated in generalized Landau gauge."
    },
    {
        "anchor": "The infrared dynamics of Minimal Walking Technicolor: We study the gauge sector of Minimal Walking Technicolor, which is an SU(2)\ngauge theory with nf=2 flavors of Wilson fermions in the adjoint\nrepresentation. Numerical simulations are performed on lattices Nt x Ns^3, with\nNs ranging from 8 to 16 and Nt=2Ns, at fixed \\beta=2.25, and varying the\nfermion bare mass m0, so that our numerical results cover the full range of\nfermion masses from the quenched region to the chiral limit. We present results\nfor the string tension and the glueball spectrum. A comparison of mesonic and\ngluonic observables leads to the conclusion that the infrared dynamics is given\nby an SU(2) pure Yang-Mills theory with a typical energy scale for the spectrum\nsliding to zero with the fermion mass. The typical mesonic mass scale is\nproportional to, and much larger than this gluonic scale. Our findings are\ncompatible with a scenario in which the massless theory is conformal in the\ninfrared. An analysis of the scaling of the string tension with the fermion\nmass towards the massless limit allows us to extract the chiral condensate\nanomalous dimension \\gamma*, which is found to be \\gamma*=0.22+-0.06.",
        "positive": "Lattice QCD calculation of $\u03c0^0\\rightarrow e^+ e^-$ decay: We extend the application of lattice QCD to the two-photon-mediated, order\n$\\alpha^2$ rare decay $\\pi^0\\rightarrow e^+ e^-$. By combining Minkowski- and\nEuclidean-space methods we are able to calculate the complex amplitude\ndescribing this decay directly from the underlying theories (QCD and QED) which\npredict this decay. The leading connected and disconnected diagrams are\nconsidered; a continuum limit is evaluated and the systematic errors are\nestimated. We find $\\mathrm{Re} \\mathcal{A} = 18.60(1.19)(1.04)\\,$eV,\n$\\mathrm{Im} \\mathcal{A} = 32.59(1.50)(1.65)\\,$eV, a more accurate value for\nthe ratio $\\frac{\\mathrm{Re} \\mathcal{A}}{\\mathrm{Im}\n\\mathcal{A}}=0.571(10)(4)$ and a result for the partial width\n$\\Gamma(\\pi^0\\to\\gamma\\gamma) = 6.60(0.61)(0.67)\\,$eV. Here the first errors\nare statistical and the second systematic. This calculation is the first step\nin determining the more challenging, two-photon-mediated decay amplitude that\ncontributes to the rare decay $K\\to\\mu^+\\mu^-$."
    },
    {
        "anchor": "Tackling the Sign Problem: To tackle the sign problem in the simulations of systems having indefinite or\ncomplex-valued measures, we propose a new approach which yields statistical\nerrors smaller than the crude Monte Carlo using absolute values of the original\nmeasures. The 1D complex-coupling Ising model is employed as an illustration.",
        "positive": "Lattice QCD with 12 Quark Flavors: A Careful Scrutiny: With a substantial amount of simulations, we have explored the system across\na wide range of lattice scales. We have located a lattice artifact, first order\nbulk transition, have studied its properties, and found that the flavor-singlet\nscalar meson mass vanishes at the critical endpoint. We will discuss the\nlattice phase diagrams and the continuum limits for both a spontaneous chiral\nsymmetry breaking phase and an infrared conformal phase, and compare results\nwith other groups."
    },
    {
        "anchor": "Improving the continuum limit of gradient flow step scaling: We introduce a non-perturbative improvement for the renormalization group\nstep scaling function based on the gradient flow running coupling, which may be\napplied to any lattice gauge theory of interest. Considering first SU(3) gauge\ntheory with $N_f = 4$ massless staggered fermions, we demonstrate that this\nimprovement can remove $O(a^2)$ lattice artifacts, and thereby increases our\ncontrol over the continuum extrapolation. Turning to the 12-flavor system, we\nobserve an infrared fixed point in the infinite-volume continuum limit.\nApplying our proposed improvement reinforces this conclusion by removing all\nobservable $O(a^2)$ effects. For the finite-volume gradient flow\nrenormalization scheme defined by $c = \\sqrt{8t} / L = 0.2$, we find the\ncontinuum conformal fixed point to be located at $g_\\star^2 = 6.2(2)$",
        "positive": "Gauge invariant field strength correlators from RG smoothing and color\n  correlations between topological charge clusters: Using the renormalization group based smoothing technique we have studied the\ngauge invariant field strength correlator at T\\ne0 and T=0 in pure SU(2) gauge\ntheory. In conjunction with a cluster analysis, the field strength correlator\nis used to study correlations between the clusters in space and color\norientation."
    },
    {
        "anchor": "Chiral transition via the Banks-Casher relation: We investigate the properties of the finite-temperature QCD transition\ntowards the chiral limit using staggered quarks. Starting from the 2+1-flavor\nphysical point, the limit of massless quarks is approached along two different\ntrajectories in the Columbia-plot. Unlike in previous approaches, the chiral\ncondensate is determined via the Banks-Casher relation. The first results of\nour finite size scaling analysis are presented.",
        "positive": "Bottomonium from lattice QCD as a probe of the Quark-Gluon Plasma: We study the temperature dependence of bottomonium for temperatures in the\nrange 0.4 Tc < T < 2.1 Tc, using non-relativistic dynamics for the bottom quark\nand full relativistic lattice QCD simulations for Nf=2 light flavors. We\nconsider the behaviour of the correlators in Euclidean space, we analyze the\nassociated spectral functions and we study the dependence on the momentum. Our\nresults are amenable to a successful comparison with effective field theories.\nThey help build a coherent picture of the behaviour of bottomonium in the\nplasma, consistent which the current LHC results."
    },
    {
        "anchor": "Static Quark Potential and the Renormalized Anisotropy on Tadpole\n  Improved Anisotropic Lattices: Static quark potential is studied using a tadpole improved gauge lattice\naction. The scale is set using the potential for a wide range of bare\nparameters.\n  The renormalized anisotropy of the lattice is also measured.",
        "positive": "Phases and fractal structures of three-dimensional simplicial gravity: We study phases and fractal structures of three-dimensional simplicial\nquantum gravity by the Monte-Carlo method. After measuring the surface area\ndistribution (SAD) which is the three-dimensional analog of the loop length\ndistribution (LLD) in two-dimensional quantum gravity, we classify the fractal\nstructures into three types: (i) in the hot (strong coupling) phase, strong\ngravity makes the space-time one crumpled mother universe with small\nfluctuating branches around it. This is a crumpled phase with a large Hausdorff\ndimension $d_{\\mbox{\\tiny H}} \\simeq 5$. The topologies of cross-sections are\nextremely complicated. (ii) at the critical point, we observe that the\nspace-time is a fractal-like manifold which has one mother universe with small\nand middle size branches around it. The Hausdorff dimension is $d_{\\mbox{\\tiny\nH}} \\simeq 4$. We observe some scaling behaviors for the cross-sections of the\nmanifold. This manifold resembles the fractal surface observed in\ntwo-dimensional quantum gravity. (iii) in the cold (weak coupling) phase, the\nmother universe disappears completely and the space-time seems to be the\nbranched-polymer with a small Hausdorff dimension $d_{\\mbox{\\tiny H}} \\simeq\n2$. Almost all of the cross-sections have the spherical topology $S^2$ in the\ncold phase."
    },
    {
        "anchor": "The Schr\u00f6dinger functional running coupling with staggered fermions: We discuss the Schr\\\"odinger functional in lattice QCD with staggered\nfermions including its order $O(a)$ boundary counterterms. We relate it, in the\nclassical continuum limit, to the Schr\\\"odinger functional as obtained in the\nsame limit with Wilson fermions. We compute the strong coupling constant\ndefined via the Schr\\\"odinger functional with staggered fermions at one loop\nand show that it agrees with the continuum running coupling constant in the\nSchr\\\"odinger functional formalism.",
        "positive": "On Spin and Matrix Models in the Complex Plane: We describe various aspects of statistical mechanics defined in the complex\ntemperature or coupling-constant plane. Using exactly solvable models, we\nanalyse such aspects as renormalization group flows in the complex plane, the\ndistribution of partition function zeros, and the question of new\ncoupling-constant symmetries of complex-plane spin models. The double-scaling\nform of matrix models is shown to be exactly equivalent to finite-size scaling\nof 2-dimensional spin systems. This is used to show that the string\nsusceptibility exponents derived from matrix models can be obtained numerically\nwith very high accuracy from the scaling of finite-$N$ partition function zeros\nin the complex plane."
    },
    {
        "anchor": "Topological susceptibility, scale setting and universality from\n  $Sp(N_c)$ gauge theories: In this contribution, we report on our study of the properties of the Wilson\nflow and on the calculation of the topological susceptibility of $Sp(N_c)$\ngauge theories for $N_c=2,\\,4,\\,6,\\,8$. The Wilson flow is shown to scale\naccording to the quadratic Casimir operator of the gauge group, as was already\nobserved for $SU(N_c)$, and the commonly used scales $t_0$ and $w_0$ are\nobtained for a large interval of the inverse coupling for each probed value of\n$N_c$. The continuum limit of the topological susceptibility is computed and we\nconjecture that it scales with the dimension of the group. The lattice\nmeasurements performed in the $SU(N_c)$ Yang-Mills theories by several\nindependent collaborations allow us to test this conjecture and to obtain a\nuniversal large-$N_c$ limit of the rescaled topological susceptibility.",
        "positive": "Flux Tubes of Two- and Three-Quark System in Full QCD: We study the abelian color flux of two- and three-quark systems in the\nmaximally abelian gauge in lattice QCD with dynamical fermions. We find that\nthe abelian flux tube formed between quark and antiquark is very much the same\nas in quenched QCD up to quark separations of $R$$\\sim$ 2fm. The profile of the\ncolor electric field in three-quark system suggests $Y$ ansatz, which might be\ninterpreted as the result of the vacuum pressure in the confined phase. In\norder to clarify the flux structure, we investigate the color electric field of\nthe three-quark system splittting the abelian gauge field into the monopole and\nphoton parts."
    },
    {
        "anchor": "Isospin-0 $\u03c0\u03c0$ s-wave scattering length from twisted mass lattice\n  QCD: We present results for the isospin-0 $\\pi\\pi$ s-wave scattering length\ncalculated with Osterwalder-Seiler valence quarks on Wilson twisted mass gauge\nconfigurations. We use three $N_f = 2$ ensembles with unitary (valence) pion\nmass at its physical value (250$\\sim$MeV), at 240$\\sim$MeV (320$\\sim$MeV) and\nat 330$\\sim$MeV (400$\\sim$MeV), respectively. By using the stochastic Laplacian\nHeaviside quark smearing method, all quark propagation diagrams contributing to\nthe isospin-0 $\\pi\\pi$ correlation function are computed with sufficient\nprecision. The chiral extrapolation is performed to obtain the scattering\nlength at the physical pion mass. Our result $M_\\pi a^\\mathrm{I=0}_0 =\n0.198(9)(6)$ agrees reasonably well with various experimental measurements and\ntheoretical predictions. Since we only use one lattice spacing, certain\nsystematics uncertainties, especially those arising from unitary breaking, are\nnot controlled in our result.",
        "positive": "Determination of Delta resonance parameters from lattice QCD: A method suitable for extracting resonance parameters of unstable baryons in\nlattice QCD is examined. The method is applied to the strong decay of the Delta\nto a pion-nucleon state, extracting the pion-nucleon - Delta coupling constant\nand Delta decay width."
    },
    {
        "anchor": "Perturbative Matching of the staggered four-fermion operators for e'/e: Using staggered fermions, we calculate the perturbative corrections to the\nbilinear and four-fermion operators that are used in the numerical study of\nweak matrix elements for $\\epsilon'/\\epsilon$. We present results for one-loop\nmatching coefficients between continuum operators, calculated in the Naive\nDimensional Regularization (NDR) scheme, and gauge invariant staggered fermion\noperators. These results, combined with existing results for penguin diagrams,\nprovide the complete one-loop renormalization of the staggered four-fermion\noperators.",
        "positive": "Vector like gauge theories with almost massless fermions on the lattice: A truncation of the overlap (domain wall fermions) is studied and a criterion\nfor reliability of the approximation is obtained by comparison to the exact\noverlap formula describing massless quarks. We also present a truncated version\nof regularized, pure gauge, supersymmetric models. The mechanism for generating\nalmost masslessness is shown to be a generalized see-saw which can also be\nviewed as a version of Froggatt-Nielsen's method for obtaining natural large\nmass hierarchies. Viewed in this way the mechanism preserving the mass\nhierarchy naturally avoids preserving even approximately axial U(1). The new\ninsights into the source of the mass hierarchy suggest ways to increase the\nefficiency of numerical simulations of QCD employing the truncated overlap."
    },
    {
        "anchor": "Currents, chemical potential and boundary conditions in lattice QCD: A connection between the operator fermionic currents $\\hatJ$ and\ncorresponding `Grassmannian' currents $J$ in the functional integral formalism\nis studied. The QCD action with non--zero chemical potential $\\mu$ is derived.\nA connection between the fermionic Fock space and boundary conditions along the\nforth direction is discussed.",
        "positive": "A deconstruction lattice description of the D1/D5 brane world-volume\n  gauge theory: In this article, I generalize the deconstruction lattice formulation of\nEndres and Kaplan [hep-lat/0604012] to two-dimensional super-QCD with eight\nsupercharges, denoted (4,4), and bifundamental matter. I specialize to a\nparticularly interesting (4,4) gauge theory, with gauge group U(N_c) \\times\nU(N_f), and U(N_f) weakly gauged. It describes the infrared limit of the D1/D5\nbrane system, which has been studied extensively as an example of the\nAdS_3/CFT_2 correspondence. The construction here preserves two supercharges\nexactly, and has a lattice structure quite similar to that which has previously\nappeared in the deconstruction approach; i.e., site, link and diagonal fields\nwith both Bose and Fermi statistics. I remark on possible applications of the\nlattice theory that would test the AdS_3/CFT_2 correspondence, particularly one\nthat would exploit the recent worldsheet instanton analysis of Chen and Tong\n[hep-th/0604090]."
    },
    {
        "anchor": "Grand-Canonical simulation of 4D simplicial quantum gravity: A thorough numerical examination for the field theory of 4D quantum gravity\n(QG) with a special emphasis on the conformal mode dependence has been studied.\nMore clearly than before, we obtain the string susceptibility exponent of the\npartition function by using the Grand-Canonical Monte-Carlo method. Taking\nthorough care of the update method, the simulation is made for 4D Euclidean\nsimplicial manifold coupled to $N_X$ scalar fields and $N_A$ U(1) gauge fields.\nThe numerical results suggest that 4D simplicial quantum gravity (SQG) can be\nreached to the continuum theory of 4D QG. We discuss the significant property\nof 4D SQG.",
        "positive": "A Concise Force Calculation for Hybrid Monte Carlo with Improved Actions: We present a concise way to calculate force for Hybrid Monte Carlo with\nimproved actions using the fact that changes in thin and smeared link matrices\nlie in their respective tangent vector spaces. Since hypercubic smearing\nschemes are very memory intensive, we also present a memory optimized\nimplementation of them."
    },
    {
        "anchor": "Applying Complex Langevin to Lattice QCD at finite $\u03bc$: We continue our simulations of lattice QCD at finite quark-number chemical\npotential, $\\mu$, using the complex-Langevin equation (CLE) with gauge-cooling\nand adaptive updating. The CLE is used because QCD at finite finite $\\mu$ has a\ncomplex fermion determinant, which prevents use of standard simulation methods.\nSimulations using the standard lattice action show a transition from hadronic\nto nuclear matter for $\\mu < m_\\pi/2$ rather than the expected $\\mu \\approx\nm_N/3$. This suggests that the CLE is being influenced by the phase-quenched\ntheory, which has a transition at $\\mu = m_\\pi/2$. We are therefore performing\nCLE simulations with a new action which includes an irrelevant chiral 4-fermion\ninteraction. This separates the physics at energies of order of the pion mass\nand smaller from that at energies of the other hadrons. In doing this, it\nbreaks the extended symmetry of the phase-quenched theory over that of the full\ntheory, raising the masses of the extra pion-like excitations consisting of a\nquark and a conjugate quark, which could otherwise produce such an anomalous\ntransition. Our preliminary CLE simulations using massless quarks, so that\n$m_\\pi=0$, show no transition at $\\mu=m_\\pi/2=0$, but do show a transition at\nan appreciably higher value of $\\mu$. It remains to be seen if this transition\nis near to $m_N/3$.",
        "positive": "Lattice determination of the topological susceptibility slope\n  $\u03c7^\\prime$ of $2d~\\mathrm{CP}^{N-1}$ models at large $N$: We compute the topological susceptibility slope $\\chi^\\prime$, related to the\nsecond moment of the two-point correlator of the topological charge density, of\n$2d$ $\\mathrm{CP}^{N-1}$ models for $N=5,11,21$ and $31$ from lattice Monte\nCarlo simulations. Our strategy consists in performing a double limit: first,\nwe take the continuum limit of $\\chi^\\prime$ at fixed smoothing radius in\nphysical units; then, we take the zero-smoothing-radius limit. Since the same\nstrategy can also be applied to $4d$ gauge theories and full QCD, where\n$\\chi^\\prime$ plays an intriguing theoretical and phenomenological role, this\nwork constitutes a step towards the lattice investigation of this quantity in\nsuch models."
    },
    {
        "anchor": "Towards a semi-classical description of QCD vacuum around $T_c$: We study the vacuum topology of 2+1 flavor QCD above the chiral crossover\ntransition, at $T \\lesssim 1.2~T_c$, on lattices of size $32^3\\times 8$. Since\noverlap fermions have exact chiral symmetry and an index theorem even on a\nfinite lattice, we use them to detect the topological content of gauge fields\ngenerated using domain wall fermion discretization for quarks. We further use\ndifferent periodicity phases along the temporal direction for the valence\noverlap quarks, which allows us to probe different topological structures\npresent in the gauge field ensembles, through its zero modes. This procedure\nprovides strong evidences that fermion zero-modes can be quantitatively\nunderstood to arise due to different species of instanton-dyons. We estimate\ntheir relative abundances from the Dirac-eigenvalue density and resolve the so\ncalled \"topological clusters\" via multi-parameter fits to their density,\nproviding therefore an understanding of the interactions between\ninstanton-dyons. The typical separation between dyons we obtain, is $\\sim 0.3$\nfm. Surprisingly, it emerges out from this study that a semi-classical\ndescription of the fermionic zero modes in the QCD vacuum is quite accurate\njust above $T_c$.",
        "positive": "Finite-size scaling tests for spectra in SU(3) lattice gauge theory\n  coupled to 12 fundamental flavor fermions: I carry out a finite-size scaling study of the correlation length in SU(3)\nlattice gauge theory coupled to 12 fundamental flavor fermions, using recent\ndata published by Fodor, Holland, Kuti, Nogradi and Schroeder. I make the\nassumption that the system is conformal in the zero-mass, infinite volume\nlimit, that scaling is violated by both nonzero fermion mass and by finite\nvolume, and that the scaling function in each channel is determined\nself-consistently by the data. From several different observables I extract a\ncommon exponent for the scaling of the correlation length xi with the fermion\nmass m_q, xi proportional to m_q to the power -1/y_m, with y_m ~ 1.35.\nShortcomings of the analysis are discussed."
    },
    {
        "anchor": "A numerical treatment of Neuberger's lattice Dirac operator: We describe in some detail our numerical treatment of Neuberger's lattice\nDirac operator as implemented in a practical application. We discuss the\nimprovements we have found to accelerate the numerical computations and give an\nestimate of the expense when using this operator in practice.",
        "positive": "Nucleon electric polarizabilities and nucleon-pion scattering at\n  physical pion mass: We present a lattice QCD calculation of the nucleon electric polarizabilities\nat the physical pion mass. Our findings reveal the substantial contributions of\nthe $N\\pi$ states to these polarizabilities. Without considering these\ncontributions, the lattice results fall significantly below the experimental\nvalues, consistent with previous lattice studies. This observation has\nmotivated us to compute both the parity-negative $N\\pi$ scattering length and\n$N\\gamma^*\\to N\\pi$ matrix elements using lattice QCD. Our results confirm that\nthe inclusion of dynamic $N\\pi$ contributions allows for reliable determination\nof the polarizabilities from lattice QCD. This methodology lays the groundwork\nfor future lattice QCD investigations into various other polarizabilities."
    },
    {
        "anchor": "'t Hooft anomalies for staggered fermions: We show that the phase structure of certain staggered fermion theories can be\nunderstood on the basis of exact anomalies. These anomalies arise when\nstaggered fermions are coupled to gravity which can be accomplished by\nreplacing them by discrete K\\\"{a}hler-Dirac fermions. We first show the\nexistence of a perturbative anomaly in even dimensions which breaks an exact\n$U(1)$ symmetry of the massless theory down to $Z_4$. If we attempt to gauge\nthis $Z_4$ symmetry we find a 't Hooft anomaly which can only be cancelled for\nmultiples of two K\\\"{a}hler-Dirac fields. This result is consistent with the\ncancellation of a further mixed non-perturbative 't Hooft anomaly between the\nglobal $Z_4$ and a reflection symmetry. In four dimensional flat space,\ntheories of two staggered fields yield eight Dirac or sixteen Majorana fermions\nin the continuum limit and this critical number of fermions agrees with results\nin condensed matter theory literature on the fermion content required to gap\nboundary fermions in $4+1$ dimensional topological superconductors. It is also\nconsistent with constraints stemming from the cancellation of spin-$Z_4$\nanomalies of Weyl fermions. Indeed, cancellation of 't Hooft anomalies is a\nnecessary requirement for symmetric mass generation and this result gives a\ntheoretical explanation of recent numerical work on the phase diagram of\ninteracting staggered fermions. As an application of these ideas we construct a\nlattice model whose low energy continuum limit is conjectured to yield the\nPati-Salam GUT theory.",
        "positive": "$\u0394I = 3/2$ and $\u0394I = 1/2$ channels of $K\\to\u03c0\u03c0$ decay at\n  the physical point with periodic boundary conditions: We present a lattice calculation of the $K\\to\\pi\\pi$ matrix elements and\namplitudes with both the $\\Delta I = 3/2$ and 1/2 channels and $\\varepsilon'$,\nthe measure of direct $CP$ violation. We use periodic boundary conditions\n(PBC), where the correct kinematics of $K\\to\\pi\\pi$ can be achieved via an\nexcited two-pion final state. To overcome the difficulty associated with the\nextraction of excited states, our previous work \\cite{Bai:2015nea,RBC:2020kdj}\nsuccessfully employed G-parity boundary conditions, where pions are forced to\nhave non-zero momentum enabling the $I=0$ two-pion ground state to express the\non-shell kinematics of the $K\\to\\pi\\pi$ decay. Here instead we overcome the\nproblem using the variational method which allows us to resolve the two-pion\nspectrum and matrix elements up to the relevant energy where the decay\namplitude is on-shell.\n  In this paper we report an exploratory calculation of $K\\to\\pi\\pi$ decay\namplitudes and $\\varepsilon'$ using PBC on a coarser lattice size of\n$24^3\\times64$ with inverse lattice spacing $a^{-1}=1.023$ GeV and the physical\npion and kaon masses. The results are promising enough to motivate us to\ncontinue our measurements on finer lattice ensembles in order to improve the\nprecision in the near future."
    },
    {
        "anchor": "Monopole Percolation in pure gauge compact QED: The role of monopoles in quenched compact QED has been studied by measuring\nthe cluster susceptibility and the order parameter $n_{max}/n_{tot}$ previously\nintroduced by Hands and Wensley in the study of the percolation transition\nobserved in non-compact QED. A correlation between these parameters and the\nenergy (action) at the phase transition has been observed. We conclude that the\norder parameter $n_{max}/n_{tot}$ is a sensitive probe for studying the phase\ntransition of pure gauge compact QED.",
        "positive": "$O(a^2)$-improved actions for heavy quarks and scaling studies on\n  quenched lattices: We investigate a new class of improved relativistic fermion action on the\nlattice with a criterion to give excellent energy-momentum dispersion relation\nas well as to be consistent with tree-level $O\\left(a^{2}\\right)$-improvement.\nMain application in mind is that for heavy quark for which $ma\\simeq O(0.5)$.\nWe present tree-level results and a scaling study on quenched lattices."
    },
    {
        "anchor": "The functional form of open Wilson lines in gauge theories coupled to\n  matter: The open Wilson lines are gauge-invariant operators made with a gauge\ntransporter along an open path saturated at the end-points with matter fields.\nHere it is shown that numerical experiments on 3D Z2 Higgs model provide useful\nguidance in addressing the problem of the functional form of their vacuum\nexpectation values. It turns out they satisfy, as long as their size does not\nexceed the string breaking scale, a remarkable factorization, related to\nfinite-size scaling of the Fredenhagen-Marcu order parameter. This leads to\nconjecture a decay area law, like ordinary Wilson loops, with the difference\nthat the boundary conditions of the confining string world-sheet are fixed\nalong the path of the gauge transporter whereas are free on the straight line\njoining the two end-points. A consistency condition fixes uniquely the\ncontribution of the free boundary, which turns out to be proportional to the\nstring-breaking scale. Universal shape effects produced by quantum string\nfluctuations are also studied.",
        "positive": "Nucleon electromagnetic and axial form factors with N$_f$=2 twisted mass\n  fermions at the physical point: We present results for the nucleon electromagnetic and axial form factors\nusing an N$_f$=2 twisted mass fermion ensemble with pion mass of about 131 MeV.\nWe use multiple sink-source separations to identify excited state\ncontamination. Dipole masses for the momentum dependence of the form factors\nare extracted and compared to experiment, as is the nucleon magnetic moment and\ncharge and magnetic radii."
    },
    {
        "anchor": "Cluster Percolation and Chiral Phase Transition: The Meron Cluster algorithm solves the sign problem in a class of interacting\nfermion lattice models with a chiral phase transition. Within this framework,\nwe study the geometrical features of the clusters built by the algorithm, that\nsuggest the occurrence of a generalized percolating phase transition at the\nchiral critical temperature in close analogy with Fortuin-Kasteleyn percolation\nin spin models.",
        "positive": "Study of decuplet baryon resonances from lattice QCD: A lattice QCD study of the strong decay width and coupling constant of\ndecuplet baryons to an octet baryon - pion state is presented. The transfer\nmatrix method is used to obtain the overlap of lattice states with decuplet\nbaryon quantum numbers on the one hand and octet baryon-pion quantum numbers on\nthe other as an approximation to the matrix element of the corresponding\ntransition. By making use of leading order effective field theory, the coupling\nconstants, as well as the widths for the various decay channels are determined.\nThe transitions studied are $ \\Delta \\to \\pi \\,N$, $\\Sigma^* \\to \\Lambda\\,\\pi$,\n$\\Sigma^* \\to \\Sigma\\,\\pi$ and $\\Xi^* \\to \\Xi\\,\\pi$. We obtain results for two\nensembles of $N_f=2+1$ dynamical fermion configurations, one using domain wall\nvalence quarks on a staggered sea at a pion mass of $350\\,\\mathrm{MeV}$ and a\nbox size of $3.4\\,\\mathrm{fm}$ and a second one using domain wall sea and\nvalence quarks at pion mass $180\\,\\mathrm{MeV}$ and box size\n$4.5\\,\\mathrm{fm}$."
    },
    {
        "anchor": "Blockspin Cluster Algorithms for Quantum Spin Systems: Cluster algorithms are developed for simulating quantum spin systems like the\none- and two-dimensional Heisenberg ferro- and anti-ferromagnets. The\ncorresponding two- and three-dimensional classical spin models with four-spin\ncouplings are maped to blockspin models with two-blockspin interactions.\nClusters of blockspins are updated collectively. The efficiency of the method\nis investigated in detail for one-dimensional spin chains. Then in most cases\nthe new algorithms solve the problems of slowing down from which standard\nalgorithms are suffering.",
        "positive": "Gluon Propagators in Maximally Abelian Gauge in SU(3) Lattice QCD: In SU(3) lattice QCD, we study diagonal and off-diagonal gluon propagators in\nthe maximally Abelian (MA) gauge with U(1)$_3 \\timesU(1)_8$ Landau gauge\nfixing. These propagators are studied both in the coordinate space and in the\nmomentum space. The Monte Carlo simulation is performed on $16^4$ at\n$\\beta$=6.0 and $32^4$ at $\\beta$=5.8 and 6.0 at the quenched level. In the\nfour-dimensional Euclidean space-time, the effective mass of diagonal gluons is\nestimated as $M_{\\mathrm{diag}} \\simeq 0.3\\mathrm{GeV}$ and that of\noff-diagonal gluons as $M_{\\mathrm{off}} \\simeq 1\\mathrm{GeV}$ in the region of\n$r =0.4-1.0$fm. In the momentum space, the effective mass of diagonal gluons is\nestimated as $M_{\\mathrm{diag}} \\simeq 0.3\\mathrm{GeV}$ and that of\noff-diagonal gluons as $M_{\\mathrm{off}} \\simeq 1\\mathrm{GeV}$ in the region of\n$p <1.1$GeV. The off-diagonal gluon propagator is relatively suppressed in the\ninfrared region and seems to be finite at zero momentum, while the diagonal\ngluon propagator is enhanced. Furthermore, we also study the functional form of\nthese propagators in momentum space. These propagators are well fitted by\n$Z/(p^2+m^2)^\\nu$ with fit parameters, $Z, m$ and $\\nu$ in the region of $p\n<3.0$GeV. From the fit results and lattice calculations, all of the spectral\nfunctions of diagonal and off-diagonal gluons would have negative regions."
    },
    {
        "anchor": "Reconstructed (charm) baryon methods at finite temperature on\n  anisotropic lattices: Reconstructed-correlator methods have been used to investigate thermal\neffects in mesonic correlation functions in a fit-independent manner. This\ntechnique has recently been extended to the baryonic sector. In this work\ndifferent ways of implementing this approach for baryon correlators are\nexamined. Using both real and synthetic data it is found that for heavy\nbaryons, such as the $\\Xi_{cc}(ccu)$ baryon, different choices are equivalent\nand that for the lighter nucleon the effect of different implementations is\nminimal. Further comparison to the so-called \"double ratio\" using the FASTSUM\nGeneration 2L thermal ensembles shows that reconstructed-correlator ratios and\ndouble ratios contain nearly identical quantitative information.",
        "positive": "Order, Disorder and Confinement: Studying the order of the chiral transition for $N_f=2$ is of fundamental\nimportance to understand the mechanism of color confinement. We present results\nof a numerical investigation on the order of the transition by use of a novel\nstrategy in finite size scaling analysis. The specific heat and a number of\nsusceptibilities are compared with the possible critical behaviours. A second\norder transition in the O(4) and O(2) universality classes are excluded.\nSubstantial evidence emerges for a first order transition. Results are in\nagreement with those found by studying the scaling properties of a disorder\nparameter related to the dual superconductivity mechanism of color confinement."
    },
    {
        "anchor": "Selected inversion as key to a stable Langevin evolution across the QCD\n  phase boundary: We present new results of full QCD at nonzero chemical potential. In PRD 92,\n094516 (2015) the complex Langevin method was shown to break down when the\ninverse coupling decreases and enters the transition region from the deconfined\nto the confined phase. We found that the stochastic technique used to estimate\nthe drift term can be very unstable for indefinite matrices. This may be\navoided by using the full inverse of the Dirac operator, which is, however, too\ncostly for four-dimensional lattices. The major breakthrough in this work was\nachieved by realizing that the inverse elements necessary for the drift term\ncan be computed efficiently using the selected inversion technique provided by\nthe parallel sparse direct solver package PARDISO. In our new study we show\nthat no breakdown of the complex Langevin method is encountered and that\nsimulations can be performed across the phase boundary.",
        "positive": "Perfect Abelian dominance of quark confinement in SU(3) QCD: We study the Abelian projection of quark confinement in SU(3) quenched\nlattice QCD, in terms of the dual superconductor picture. In the maximal\nAbelian gauge, we perform the Cartan decomposition of the non-Abelian gauge\nfield on a $32^4$ lattice with spacing $a \\simeq0.058, 0.10$ fm (i.e., $\\beta\n=6.4, 6.0$), and investigate the interquark potential $V(r)$, the Abelian part\n$V_{\\mathrm{Abel}}(r)$, and the off-diagonal part $V_{\\mathrm{off}}(r)$. For\nthe potential analysis, we use both on-axis data and several types of off-axis\ndata, with larger numbers of gauge configurations. Remarkably, we find almost\nperfect Abelian dominance of the string tension (quark-confining force) on the\nlarge-volume lattice. Also, we find a simple but nontrivial relation of $V(r)\n\\simeq V_{\\mathrm{Abel}}(r) + V_{\\mathrm{off}}(r)$."
    },
    {
        "anchor": "The $1/N$ expansion of two-dimensional spin models: A general two-dimensional spin model with U$(N)$ invariance, interpolating\nbetween $\\CPN$ and ${\\rm O}(2N)$ models, is studied in detail in order to\nillustrate both the general features of the $1/N$ expansion on the lattice and\nthe specific techniques devised to extract scaling (field-theoretical)\nbehavior. The continuum version of the model is carefully analyzed deriving\nquantitative $O(1/N)$ physical predictions in order to establish a benchmark\nfor lattice computations. The $1/N$ expansion on the lattice, including\nsecond-nearest-neighbor interactions, is set up by constructing explicitly\neffective propagators and vertices. The technique of asymptotic expansion of\nthe lattice propagators, basic to the derivation of analytical results in the\nscaling domain, is presented in full detail and applied to the model. Physical\nquantities, like the free energy and different definitions of correlation\nlength, are evaluated. The lattice renormalization-group trajectories are\nidentified and universality among different lattice (and continuum) schemes in\nthe scaling region is explicitly proven. A review of other developments based\non the lattice $1/N$ expansion is presented.",
        "positive": "The phase transition in QCD with broken SU(2) flavour symmetry: We report the first investigation of the QCD transition temperature, T_c, for\ntwo flavours of staggered quarks with unequal masses at lattice spacings of\n1/4T. On changing the u/d quark mass ratio in such a way that\nm(pi_0)^2/m(pi_+)^2 changes from 1 to 0.78, thus bracketing the physical value\nof this ratio, we find that T_c remains unchanged in units of both m_rho and\nLambda_MSbar."
    },
    {
        "anchor": "The anti-quark--quark potential from Bethe-Salpeter amplitudes on\n  lattice: Potentials of quark--anti-quark pairs are studied from the anti-q--q\nNambu-Bethe-Salpeter (NBS) wave functions in quenched lattice QCD. With the use\nof a method which has been recently developed in the derivation of nuclear\nforces from QCD, we derive the anti-q--q potentials with finite quark masses\nfrom the NBS wave functions. We calculate the anti-q--q NBS wave functions in\npseudo-scalar and vector channels for several quark masses. The derived\npotentials in both channels reveal linear confinement plus Coulomb potentials.\nWe also discuss the quark-mass and channel dependence of the anti-q--q\npotentials.",
        "positive": "Lattice Landau Gauge and Algebraic Geometry: Finding the global minimum of a multivariate function efficiently is a\nfundamental yet difficult problem in many branches of theoretical physics and\nchemistry. However, we observe that there are many physical systems for which\nthe extremizing equations have polynomial-like non-linearity. This allows the\nuse of Algebraic Geometry techniques to solve these equations completely. The\nglobal minimum can then straightforwardly be found by the second derivative\ntest. As a warm-up example, here we study lattice Landau gauge for compact U(1)\nand propose two methods to solve the corresponding gauge-fixing equations. In a\nfirst step, we obtain all Gribov copies on one and two dimensional lattices.\nFor simple 3x3 systems their number can already be of the order of thousands.\nWe anticipate that the computational and numerical algebraic geometry methods\nemployed have far-reaching implications beyond the simple but illustrating\nexamples discussed here."
    },
    {
        "anchor": "Pade approximants and g-2 for the muon: The leading hadronic contribution to the muon anomalous magnetic moment is\ngiven by a weighted euclidean momentum integral of the hadronic vacuum\npolarization. This integral is dominated by momenta of order the muon mass.\nSince in lattice QCD it is difficult to compute the vacuum polarization at a\nlarge number of low momenta, a parametrization of the vacuum polarization is\nrequired to extrapolate the data. Most fits to date are based on vector meson\ndominance, which introduces model dependence into the lattice computation of\nthe magnetic moment. Here we introduce a model-independent extrapolation\nmethod, and present a few first tests of this new method.",
        "positive": "$B_c$ decays from highly improved staggered quarks and NRQCD: We calculate semileptonic form factors for the decays $B_c \\to \\eta_c \\, l\n\\nu$ and $B_c \\to J/\\psi \\, l \\nu$ over the entire $q^2$ range, using a highly\nimproved lattice quark action for charm at several lattice spacings down to\n$a=0.045$ fm. We have two ways of treating the $b$ quark: either with an\n$O(\\alpha_s)$ improved NRQCD formalism or by extrapolating a heavy mass $m_h$\nto $m_b$ in the relativistic formalism. Comparison of the two approaches\nprovides an important cross-check of methodologies in lattice QCD.\nNonperturbative renormalisation of the currents in the relativistic theory also\nallows us then to fix NRQCD-charm normalisation for $b$ to $c$ decays such as\n$B \\to D$ and $B \\to D^*$."
    },
    {
        "anchor": "Simulations with dynamical HISQ quarks: We report on the status of a program of generating and using configurations\nwith four flavors of dynamical quarks, using the HISQ action. We study the\nlattice spacing dependence of physical quantities in these simulations, using\nruns at several lattice spacings, but with the light quark mass held fixed at\ntwo tenths of the strange quark mass. We find that the lattice artifacts in the\nHISQ simulations are much smaller than those in the asqtad simulations at the\nsame lattice spacings and quark masses. We also discuss methods for setting the\nscale, or assigning a lattice spacing to ensembles run at unphysical\nparameters.",
        "positive": "Hadron electric polarizability -- finite volume corrections: We use the background field method to extract the polarizability for the\nneutral \"pion\". In our previous study we found that the polarizability for this\nsystem is negative which is believed to be a finite volume artifact. To address\nthis issue, we carry out simulations for different lattice sizes and we also\nlook at the influence of the boundary conditions on these results. We find that\nfor pion masses lower than 400 MeV the polarizability remains negative even on\nlarger lattices. An infinite volume extrapolation is attempted, but the results\nare not conclusive due mainly to a lack of an analytical form for the finite\nvolume corrections for this system."
    },
    {
        "anchor": "Heavy-Quark Free Energy, Debye Mass, and Spatial String Tension at\n  Finite Temperature in Two Flavor Lattice QCD with Wilson Quark Action: We study Polyakov loop correlations and spatial Wilson loop at finite\nTemperature in two-flavor QCD simulations with the RG-improved gluon action and\nthe clover-improved Wilson quark action on a $ 16^3 \\times 4$ lattice. From the\nline of constant physics at $m_{\\rm PS}/m_{\\rm V}=0.65$ and 0.80, we extract\nthe heavy-quark free energies, the effective running coupling $g_{\\rm eff}(T)$\nand the Debye screening mass $m_D(T)$ for various color channels of heavy\nquark--quark and quark--anti-quark pairs above the critical temperature. The\nfree energies are well approximated by the screened Coulomb form with the\nappropriate Casimir factors at high temperature. The magnitude and the\ntemperature dependence of the Debye mass are compared to those of the\nnext-to-leading order thermal perturbation theory and to a phenomenological\nformula in terms of $g_{\\rm eff}(T)$. We make a comparison between our results\nwith the Wilson quark action and the previous results with the staggered quark\naction. The spatial string tension is also studied in the high temperature\nphase and is compared to the next-to-next-leading order prediction in an\neffective theory with dimensional reduction.",
        "positive": "Continuum limit of susceptibility from strong coupling expansion: Two\n  dimensional non-linear O(N) sigma model at N>= 3: Based on the strong coupling expansion, we reinvestigate the scaling behavior\nof the susceptibility chi of two-dimensional O(N) sigma model on the square\nlattice by the use of Pade-Borel approximants. To exploit the Borel transform,\nwe express the bare coupling g in series expansion in chi. At large N,\nPade-Borel approximants exhibit the scaling behavior at the four-loop level.\nThen, the estimation of the non-perturbative constant associated with the\nsusceptibility is performed for N>=3 and the results are compared with the\navailable theoretical results and Monte Carlo data."
    },
    {
        "anchor": "Monte Carlo and Renormalization Group Effective Potentials in Scalar\n  Field Theories: We study constraint effective potentials for various strongly interacting\n$\\phi^4$ theories. Renormalization group (RG) equations for these quantities\nare discussed and a heuristic development of a commonly used RG approximation\nis presented which stresses the relationships among the loop expansion, the\nSchwinger-Dyson method and the renormalization group approach. We extend the\nstandard RG treatment to account explicitly for finite lattice effects.\nConstraint effective potentials are then evaluated using Monte Carlo (MC)\ntechniques and careful comparisons are made with RG calculations. Explicit\ntreatment of finite lattice effects is found to be essential in achieving\nquantitative agreement with the MC effective potentials. Excellent agreement is\ndemonstrated for $d=3$ and $d=4$, O(1) and O(2) cases in both symmetric and\nbroken phases.",
        "positive": "Scaling in SU(3) Pure Gauge Theory with a Renormalization Group Improved\n  Action: We study the scaling properties of the static quark potential and the ratio\nof the critical temperature $T_c$ to the square root of the string tension\n$\\sigma$ in the SU(3) pure gauge theory using a renormalization group improved\naction. We first determine the critical coupling $\\beta_c$ on lattices with\ntemporal extension $N_t=3$, 4, and 6, and then calculate the static quark\npotential at the critical couplings on lattices at zero temperature. We note\nthat the static quark potentials obtained are rotationally invariant with\nerrors of at most 1 - 2 % in all the three cases, and that the potential $V(R)$\nin physical units scales in the whole region of $R$ investigated. The values of\n$T_{c}/\\sqrt{\\sigma}$ for the three cases in the infinite volume limit are\nidentical within errors. We estimate the value in the continuum limit to be\n$T_{c}/\\sqrt{\\sigma} = 0.656(4)$, which is slightly larger than the value in\nthe continuum limit from the one-plaquette action, 0.629(3)."
    },
    {
        "anchor": "Quenched QCD at finite density: $g=1$ and $g=\\infty$: We report on our ongoing effort to understand quenched lattice QCD at finite\nbaryon number density. The quenched theory is sensitive to the baryon mass both\nat strong coupling and in the scaling region. However, we find that the\nquenched model is pathological for $\\mu > m_\\pi/2$ at $\\beta= 6.0$, in\nagreement with past Lanczos analyses of the Dirac operator.",
        "positive": "Low-energy J/psi-Hadron Interactions from Quenched Lattice QCD: The J/psi-hadron interaction is a key ingredient in analyzing the J/psi\nsuppression in hot hadronic matter as well as the propagation of J/psi in\nnuclei. As a first step to clarify the J/psi-hadron interactions at low\nenergies, we have calculated J/psi-pi, J/psi-rho and J/psi-nucleon scattering\nlengths by the quenched lattice QCD simulations with Wilson fermions for\nbeta=6.2 on 24^3*48 and 32^3*48 lattices. Using the Luscher's method to extract\nthe scattering length from the simulations in a finite box, we find an\nattractive interaction in the S-wave channel for all three systems: Among\nothers, the J/psi-nucleon interaction is most attractive. Possibility of the\nJ/psi-nucleon bound state is also discussed."
    },
    {
        "anchor": "Ferrara--Zumino supermultiplet and the energy-momentum tensor in the\n  lattice formulation of 4D $\\mathcal{N}=1$ SYM: It is well-known that Noether currents in the classical four-dimensional\n$\\mathcal{N}=1$ supersymmetric Yang--Mills theory (4D $\\mathcal{N}=1$ SYM),\ni.e., the $U(1)_A$ current, the supersymmetry (SUSY) current and the\nenergy-momentum tensor, form a multiplet under SUSY, called the Ferrara--Zumino\nsupermultiplet. Inspired by this structure, we define the energy-momentum\ntensor in the lattice formulation of 4D $\\mathcal{N}=1$ SYM by a renormalized\nsuper transformation of a lattice SUSY current. By using a renormalized SUSY\nWard--Takahashi relation, the energy-momentum tensor so constructed is shown to\nbe conserved in the quantum continuum limit. Our construction of the\nenergy-momentum tensor is very explicit and usable in non-perturbative\nnumerical simulations.",
        "positive": "A Gauge-Independent Mechanism for Confinement and Mass Gap: Part I --\n  The General Framework: We propose a gauge-independent mechanism for the area-law behavior of Wilson\nloop expectation values in terms of worldsheets spanning Wilson loops\ninteracting with the spin foams that contribute to the vacuum partition\nfunction. The method uses an exact transformation of lattice-regularized\nYang-Mills theory that is valid for all couplings. Within this framework, some\nnatural conjectures can be made as to what physical mechanism enforces the\nconfinement property in the continuum (weak coupling) limit. Details for the\nSU(2) case in three dimensions are provided in a companion paper."
    },
    {
        "anchor": "Gauge Fixing and Extended Abelian Monopoles in SU(2) Gauge Theory in 2+1\n  Dimensions: Extended Abelian monopoles are investigated in SU(2) lattice gauge theory in\nthree dimensions. Monopoles are computed by Abelian projection in several\ngauges, including the maximal Abelian gauge. The number $N_m$ of extended\nmonopoles in a cube of size $m^3$ (in lattice units) is defined as the number\nof elementary ($1^3$) monopoles minus antimonopoles in the cube\n($m=1,2,\\ldots$). The distribution of $1^3$ monopoles in the nonlocal maximal\nAbelian gauge is shown to be essentially random, while nonscaling of the\ndensity of $1^3$ monopoles in some local gauges, which has been previously\nobserved, is shown to be mainly due to strong short-distance correlations. The\ndensity of extended monopoles in local gauges is studied as a function of\n$\\beta$ for monopoles of fixed physical ``size'' ($m / \\beta = {\\rm fixed}$);\nthe degree of scale violation is found to decrease substantially as the\nmonopole size is increased. The possibility therefore remains that long\ndistance properties of monopoles in local gauges may be relevant to continuum\nphysics, such as confinement.",
        "positive": "Finite size effects of a pion matrix element: We investigate finite size effects of the pion matrix element of the\nnon-singlet, twist-2 operator corresponding to the average momentum of\nnon-singlet quark densities. Using the quenched approximation, they come out to\nbe surprisingly large when compared to the finite size effects of the pion\nmass. As a consequence, simulations of corresponding nucleon matrix elements\ncould be affected by finite size effects even stronger which could lead to\nserious systematic uncertainties in their evaluation."
    },
    {
        "anchor": "Optimized $\u03b4$ - Expansion for Lattice U(1) and SU(2) with\n  Interpolating Continuum Action: Embedding the lattice gauge theory into a continuum theory allows to use the\ncontinuum action as trial action in the variational calculation. Only\noriginally divergent graphs contribute. This leads to a very simple scheme\nwhich makes it possible to write down explicit expressions for the plaquette\nenergy $E$ for U(1) in arbitrary space time dimension for the first three\norders of the expansion. For dimensions three and four one can even go up to\nfourth order. This allows a rather thorough empirical investigation of the\nconvergence properties of the $\\delta $-expansion, in particular near the phase\ntransition or the transition region, respectively. As already found in previous\nwork, the principle of minimal sensitivity can be only applied for $\\beta $\nabove a certain value, because otherwise no extremum with respect to the\nvariational parameter exists. One can, however, extend the range of\napplicability down to small $\\beta $, by calculating instead of $E$ some power\n$E^\\kappa $, or by performing an appropriate Pad\\'e transformation. We find\nexcellent agreement with the data for $\\beta $ above the transition region for\nthe second and higher orders. Below the transition region the agreement is\nrather poor in low orders, but quite impressive in fourth order. For SU(2) we\nperformed the calculation up to second order. The agreement with the data is\nsomewhat worse than in the abelian case.",
        "positive": "Non-perturbative generation of elementary fermion masses: a numerical\n  study: In this talk we present a numerical lattice study of an SU(3) gauge model\nwhere an SU(2) doublet of non-Abelian strongly interacting fermions is coupled\nto a complex scalar field doublet via a Yukawa and a Wilson-like term. The\nmodel enjoys an exact symmetry, acting on all fields, which prevents UV power\ndivergent fermion mass corrections, despite the presence of these two chiral\nbreaking operators in the Lagrangian. In the phase where the scalar potential\nis non-degenerate and fermions are massless, the bare Yukawa coupling can be\nset at a critical value at which chiral fermion transformations become\nsymmetries of the theory. Numerical simulations in the Nambu-Goldstone phase of\nthe critical theory, for which the renormalized Yukawa coupling by construction\nvanishes, give evidence for non-perturbative generation of a UV finite fermion\nmass term in the effective action."
    },
    {
        "anchor": "Dynamical Simulations with Highly Improved Staggered Quarks: It is well established that lattice artifacts can be suppressed substantially\nby the use of SU(3)-projected smeared links in the fermion action. An example\nis the Highly Improved Staggered Quark action where the ASQ-like effective\nlinks are constructed from reunitarized Fat7 links. A general procedure is\npresented for computing the derivative of the fermion action with respect to\nthe base links (fermion force) - a key component in dynamical simulations using\nmolecular dynamics evolution. The method is iterative and can be applied to\nactions with arbitrary levels of smearing and reunitarization. The cost of\ncalculating the fermion force is determined for the ASQ action and the HISQ\naction. Test results show that calculating the HISQ force is about two times\nmore expensive than the ASQ force.",
        "positive": "Baryon masses at nonzero isospin/kaon density: We present a lattice QCD calculation of the ground-state energy shifts of\nvarious baryons in a medium of pions or kaons at a single value of the quark\nmass corresponding to a pion mass of m_\\pi~390 MeV and a kaon mass of m_K~540\nMeV, and in a spatial volume V (4fm)^3. All systems are created using a\ncanonical formalism in which quark propagators are contracted into correlation\nfunctions of fixed isospin/kaon density. We study four different systems,\n\\Sigma^+(\\pi^+)^n, \\Xi^0(\\pi^+)^n, p(K^+)^n, and n(K^+)^n, for up to n=11\nmesons. From the ground-state energy shifts we extract two- and three-body\nscattering parameters, as well as linear combinations of low-energy constants\nappearing in tree-level chiral perturbation theory."
    },
    {
        "anchor": "Quenched Light Hadron Spectroscopy: Comparing the Wilson and\n  O(a)-Improved Fermion Actions: We have studied the light hadron spectrum and decay constants for quenched\nQCD at beta=6.2 on a 24^3x48 lattice. We compare the results obtained using a\nnearest-neighbour O(a)-improved (\"clover\") fermion action with those obtained\nusing the standard Wilson fermion action on the same gauge configurations. For\npseudoscalar meson masses in the range 330-800 MeV, we find no significant\ndifference between the results for the two actions. The scales obtained from\nthe string tension and mesonic sector are consistent, but higher than those\nderived from baryon masses. The ratio of the pseudoscalar decay constant to the\nvector meson mass is roughly independent of quark mass as observed\nexperimentally.",
        "positive": "Thermodynamics of One-flavour QCD: We give a brief introduction on finite temperature phase transitions in\nlattice QCD including a discussion on the identification of first order\ntransitions. We present a study of the deconfinement phase transition of\none-flavour QCD, using the multiboson algorithm on lattice of sizes $8^3$,\n$12^3$ and $16^3\\times 4$. For heavy quarks our results are characteristic of a\nfirst order phase transition which gets weaker as the quark mass decreases and\nends at a critical value of $\\kappa \\sim 0.1$ or in physical units at about 1.6\nGeV."
    },
    {
        "anchor": "Finite-Temperature QCD on the Lattice: Recent developments in finite-temperature studies of lattice QCD are\nreviewed. Topics include (i) tests of improved actions for the pure gauge\nsystem, (ii) scaling study of the two-flavor chiral transition and restoration\nof $U_A(1)$ symmetry with the Kogut-Susskind quark action, (iii) present\nunderstanding of the finite-temperature phase structure for the Wilson quark\naction. New results for finite-density QCD are briefly discussed.",
        "positive": "Lattice QCD at finite density: imaginary chemical potential: I describe the results for the critical line and the thermodynamics of\ndifferent phases of QCD which have been obtained by lattice simulations with an\nimaginary chemical potential, and review motivations and merits of the\ndifferent strategies -- Taylor expansion, Fourier analysis and Pade'\napproximants -- for analytic continuation from imaginary to real chemical\npotential. I consider phenomenological models which can be easily extended to\nthe complex chemical potential plane, thus affording a direct comparison with\nlattice data at imaginary $\\mu$: the hadronic phase and the high temperature\nlimit are amenable to a simple description, while a rather subtle interplay\nbetween thermodynamics and critical behaviour emerges in the hot phase close to\n$T_c$"
    },
    {
        "anchor": "Scalar condensate and light quark masses from overlap fermions: We have studied pseudoscalar correlation functions computed using the overlap\noperator. Within the accuracy of our calculation we find that the quark mass\ndependence agrees with the prediction of lowest-order Chiral Perturbation\nTheory (ChPT) for quark masses in the range of m ~ m_s/2-2m_s. We present the\nresults of an analysis which assumes lowest-order ChPT to be valid to extract\nthe low-energy constants Sigma and f_P, as well as the strange quark mass.\nNon-perturbative renormalization is implemented via a matching procedure with\ndata obtained using Wilson fermions in the Schroedinger functional set-up. We\nfind that the scalar condensate computed here agrees with the one obtained\npreviously through a finite-size scaling analysis.",
        "positive": "Lattice Calculations of B to K/K*l+l- form factors: This paper gives a brief review on the recent lattice QCD calculations of the\nB to K/K*l+l- semi-leptonic decay form factors."
    },
    {
        "anchor": "Considerations on Neuberger's operator: We discuss new approaches to the numerical implementation of Neuberger's\noperator for lattice fermions and the possible use of block spin\ntransformations.",
        "positive": "Chiral Fermions on the Lattice: The Overlap-Dirac operator provides a lattice regularization of massless\nvector gauge theories with an exact chiral symmetry. Practical implementations\nof this operator and recent results in quenched QCD using this Overlap-Dirac\noperator are reviewed."
    },
    {
        "anchor": "Non-degenerate light quark masses from 2+1f lattice QCD+QED: We report on a calculation of the effects of isospin breaking in Lattice\nQCD+QED. This involves using Chiral Perturbation Theory with Electromagnetic\ncorrections to find the renormalized, non-degenerate, light quark masses. The\ncalculations are carried out on QCD ensembles generated by the RBC and UKQCD\ncollaborations using Domain Wall Fermions and the Iwasaki and Iwasaki+DSDR\nGauge Actions with unitary pion masses down to 170 MeV. Non-compact QED is\ntreated in the quenched approximation. The simulations use a $32^3$ lattice\nsize with $a^{-1}=2.28(3)$ GeV (Iwasaki) and 1.37(1) (Iwasaki+DSDR). This\nbuilds on previous work from the RBC/UKQCD collaboration with lattice spacing\n$a^{-1}=1.78(4)$ GeV.",
        "positive": "High-degree Polynomial Noise Subtraction: In lattice QCD, the calculation of physical quantities from disconnected\nquark loop calculations have large variance due to the use of Monte Carlo\nmethods for the estimation of the trace of the inverse lattice Dirac operator.\nIn this work, we build upon our POLY and HFPOLY variance reduction methods by\nusing high-degree polynomials. Previously, the GMRES polynomials used were only\nstable for low-degree polynomials, but through application of a new, stable\nform of the GMRES polynomial, we have achieved higher polynomial degrees than\npreviously used. While the variance is not dependent on the trace correction\nterm within the methods, the evaluation of this term will be necessary for\nforming the vacuum expectation value estimates. This requires computing the\ntrace of high-degree polynomials, which can be evaluated stochastically through\nour new Multipolynomial Monte Carlo method. With these new high-degree noise\nsubtraction polynomials, we obtained a variance reduction for the scalar\noperator of nearly an order of magnitude over that of no subtraction on a $24^3\n\\times 32$ quenched lattice at $\\beta = 6.0$ and $\\kappa = 0.1570 \\approx\n\\kappa_{crit}$. Additionally, we observe that for sufficiently high polynomial\ndegrees, POLY and HFPOLY approach the same level of effectiveness. We also\nexplore the viability of using double polynomials for variance reduction as a\nmeans of reducing the required orthogonalization and memory costs associated\nwith forming high-degree GMRES polynomials."
    },
    {
        "anchor": "Recent results from SU(2) with one adjoint Dirac fermion: We present some results for SU(2) with one adjoint Dirac flavour from lattice\nstudies. Data for the spectroscopy, the static potential, topological charge,\nand the anomalous dimension of the fermionic condensate are included. Our\nfindings are found to be in- consistent with conventional confining behaviour,\ninstead pointing tentatively towards a theory lying within or very near the\nonset of the conformal window, with an anomalous dimension of the fermionic\ncondensate of almost 1. Implications of these findings on the building of\nmodels of strongly-interacting dynamics beyond the standard model are\ndiscussed.",
        "positive": "Effective Scalar Theory of the Electroweak Phase Transition: This talk summarizes results obtained from simulating a three dimensional\npure Order Parameter (OP) model of the Electroweak Phase Transition (EWPT). Its\ndetailed presentation appears in \\cite{karsch}."
    },
    {
        "anchor": "Is the Chiral Phase Transition in Non-Compact Lattice QED Driven by\n  Monopole Condensation?: We investigate the recent conjecture that the chiral phase transition in\nnon-compact lattice QED is driven by monopole condensation. The comparison of\nanalytic and numerical results shows that we have a quantitative understanding\nof monopoles in both the quenched and dynamical cases. We can rule out monopole\ncondensation.",
        "positive": "The Color-Flavor Transformation and Lattice QCD: We present the color-flavor transformation for gauge group SU(N_c) and\ndiscuss its application to lattice QCD."
    },
    {
        "anchor": "Extracting scattering parameters using the isospin chemical potential: Hadronic scattering mediated through the strong interaction has been an area\nof great interest for both theory and experiment. Recently, lattice QCD\ncalculations of scattering processes from first principles have seen remarkable\nprogress, including multiple calculations of two-pion scattering lengths that\nagree with experiment to within a few percent. However, there exists a certain\nclass of scattering processes, such as pion-nucleon scattering, that contain\nannihilation diagrams, which are often prohibitively expensive to simulate on\nthe lattice. In this talk, I will present a method to extract certain\nparameters from this class of scattering processes by employing an isospin\nchemical potential, which can be simulated on the lattice as a result of its\npositive-definite fermion determinant.",
        "positive": "Ab initio calculation of the $np \\to d \u03b3$ radiative capture process: Lattice QCD calculations of two-nucleon systems are used to isolate the\nshort-distance two-body electromagnetic contributions to the radiative capture\nprocess $np \\to d\\gamma$, and the photo-disintegration processes\n$\\gamma^{(\\ast)} d \\to np$. In nuclear potential models, such contributions are\ndescribed by phenomenological meson-exchange currents, while in the present\nwork, they are determined directly from the quark and gluon interactions of\nQCD. Calculations of neutron-proton energy levels in multiple background\nmagnetic fields are performed at two values of the quark masses, corresponding\nto pion masses of $m_\\pi \\sim 450$ and 806 MeV, and are combined with pionless\nnuclear effective field theory to determine these low-energy inelastic\nprocesses. Extrapolating to the physical pion mass, a cross section of\n$\\sigma^{lqcd}(np\\to d\\gamma)=332.4({\\tiny \\begin{array}{l}+5.4 \\\\ -\n4.7\\end{array}})\\ mb$ is obtained at an incident neutron speed of $v=2,200\\\nm/s$, consistent with the experimental value of $\\sigma^{expt}(np \\to d\\gamma)\n= 334.2(0.5)\\ mb$."
    },
    {
        "anchor": "Lattice-QCD Determination of the Hyperon Axial Couplings in the\n  Continuum Limit: We present the first continuum extrapolation of the hyperon octet axial\ncouplings ($g_{\\Sigma \\Sigma}$ and $g_{\\Xi \\Xi}$) from $N_f=2+1+1$ lattice QCD.\nThese couplings are important parameters in the low-energy effective field\ntheory description of the octet baryons and fundamental to the nonleptonic\ndecays of hyperons and to hyperon-hyperon and hyperon-nucleon scattering with\napplication to neutron stars. We use clover lattice fermion action for the\nvalence quarks with sea quarks coming from configurations of $N_f=2+1+1$ highly\nimproved staggered quarks (HISQ) generated by MILC Collaboration. Our work\nincludes the first calculation of $g_{\\Sigma \\Sigma}$ and $g_{\\Xi \\Xi}$\ndirectly at the physical pion mass on the lattice, and a full account of\nsystematic uncertainty, including excited-state contamination, finite-volume\neffects and continuum extrapolation, all addressed for the first time. We find\nthe continuum-limit hyperon coupling constants to be $g_{\\Sigma\n\\Sigma}=0.4455(55)_\\text{stat}(65)_\\text{sys}$ and $g_{\\Xi \\Xi}\n=-0.2703(47)_\\text{stat}(13)_\\text{sys}$, which correspond to low-energy\nconstants of $D = 0.708(10)_\\text{stat}(6)_\\text{sys}$ and $F =\n0.438(7)_\\text{stat}(6)_\\text{sys}$. The corresponding SU(3) symmetry breaking\nis 9\\% which is about a factor of 2 smaller than the earlier lattice estimate.",
        "positive": "Instabilities in Molecular Dynamics Integrators used in Hybrid Monte\n  Carlo Simulations: We discuss an instability in the leapfrog integration algorithm, widely used\nin current Hybrid Monte Carlo (HMC) simulations of lattice QCD. We demonstrate\nthe instability in the simple harmonic oscillator (SHO) system where it is\nmanifest. We demonstrate the instability in HMC simulations of lattic QCD with\ndynamical Wilson-Clover fermions and discuss implications for future\nsimulations of lattice QCD."
    },
    {
        "anchor": "Neutron-Antineutron Operator Renormalization: Baryon number symmetry violating theories beyond the standard model with\nsuppressed proton decay rates can be experimentally constrained by data on\nneutron-antineutron transition rates. In order to apply this constraints,\ntheoretical predictions for the neutron-antineutron transition rates in various\nmodels must be available for comparison. Reliable predictions of transition\nrates between hadronic states must include non-perturbative quantum\nchromodynamic effects. These can be calculated in a model independent way by\ncalculating six-quark operator matrix elements with lattice quantum\nchromodynamics. Preliminary lattice calculations have been performed, but\noperator renormalization effects must be included in order to match beyond the\nstandard model calculations performed in $\\overline{MS}$ renormalized\nperturbation theory with lattice regularized matrix element results. In\nparticular, a perturbative calculation of the two-loop anomalous dimensions and\none-loop renormalization scheme matching coefficients of these six-quark\noperators is necessary in order to determine leading order corrections at\nlattice matching scales. This describes our ongoing calculation of these\nperturbative operator renormalization effects.",
        "positive": "Phase diagram at finite temperature and quark density in the strong\n  coupling limit of lattice QCD for color SU(3): We study the phase diagram of quark matter at finite temperature (T) and\nfinite chemical potential (mu) in the strong coupling limit of lattice QCD for\ncolor SU(3). We derive an analytical expression of the effective free energy as\na function of T and mu, including baryon effects. The finite temperature\neffects are evaluated by integrating over the temporal link variable exactly in\nthe Polyakov gauge with anti-periodic boundary condition for fermions. The\nobtained phase diagram shows the first order phase transition at low\ntemperatures and the second order phase transition at high temperatures\nseparated by the tri-critical point in the chiral limit. Baryon has effects to\nreduce the effective free energy and to extend the hadron phase to a larger mu\ndirection at low temperatures."
    },
    {
        "anchor": "The Weakly Coupled Gross-Neveu Model with Wilson Fermions: The nature of the phase transition in the lattice Gross-Neveu model with\nWilson fermions is investigated using a new analytical technique. This involves\na new type of weak coupling expansion which focuses on the partition function\nzeroes of the model. Its application to the single flavour Gross-Neveu model\nyields a phase diagram whose structure is consistent with that predicted from a\nsaddle point approach. The existence of an Aoki phase is confirmed and its\nwidth in the weakly coupled region is determined. Parity, rather than chiral\nsymmetry breaking naturally emerges as the driving mechanism for the phase\ntransition.",
        "positive": "Infrared conformality and bulk critical points: SU(2) with heavy adjoint\n  quarks: The lattice phase structure of a gauge theory can be a serious obstruction to\nMonte Carlo studies of its continuum behaviour. This issue is particularly\ndelicate when numerical studies are performed to determine whether a theory is\nin a (near-)conformal phase. In this work we investigate the heavy mass limit\nof the SU(2) gauge theory with Nf=2 adjoint fermions and its lattice phase\ndiagram, showing the presence of a critical point ending a line of first order\nbulk phase transition. The relevant gauge observables and the low-lying\nspectrum are monitored in the vicinity of the critical point with very good\ncontrol over different systematic effects. The scaling properties of masses and\nsusceptibilities open the possibility that the effective theory at criticality\nis a scalar theory in the universality class of the four-dimensional Gaussian\nmodel. This behaviour is clearly different from what is observed for SU(2)\ngauge theory with two dynamical adjoint fermions, whose (near-)conformal\nnumerical signature is hence free from strong-coupling bulk effects."
    },
    {
        "anchor": "Charmless chiral perturbation theory for N_f=2+1+1 twisted mass lattice\n  QCD: The chiral Lagrangian describing the low-energy behavior of N_f=2+1+1 twisted\nmass lattice QCD is constructed through O(a^2). In contrast to existing results\nthe effects of a heavy charm quark are consistently removed, leaving behind a\ncharmless 3-flavor Lagrangian. This Lagrangian is used to compute the pion and\nkaon masses to one loop in a regime where the pion mass splitting is large and\ntaken as a leading order effect. In comparison with continuum chiral\nperturbation theory additional chiral logarithms are present in the results. In\nparticular, chiral logarithms involving the neutral pion mass appear. These\npredict rather large finite volume corrections in the kaon mass which roughly\naccount for the finite volume effects observed in lattice data.",
        "positive": "Lattice QCD simulation at finite chiral chemical potential: Chiral chemical potential does not cause the sign problem in the Monte Carlo\nsimulation of lattice QCD. Using the chiral chemical potential, we study the\nchiral magnetic effect in two-flavor full QCD. We show that a strong external\nmagnetic field induces an electric current in a chirally imbalanced QCD matter.\nThe qualitative feature of the induced current is consistent with an analytical\nprediction."
    },
    {
        "anchor": "Numerical test of the Gribov-Zwanziger scenario in Landau gauge: We review the status of lattice simulations of gluon and ghost propagators in\nLandau gauge, testing predictions of the Gribov-Zwanziger confinement scenario.",
        "positive": "Dual simulation of the 2-dimensional lattice U(1) gauge-Higgs model with\n  a topological term: The 2-dimensional U(1) gauge-Higgs model with a topological term is a simple\nexample of a lattice field theory where the complex action problem comes from\nthe topological term. We show that the model can be exactly rewritten in terms\nof dual variables, such that the dual partition sum has only real and positive\ncontributions. Using suitable algorithms the dual formulation allows for Monte\nCarlo simulations at arbitrary values of the vacuum angle. We demonstrate the\nfeasibility of the dual simulation and study the continuum limit, as well as\nthe phase diagram of the system."
    },
    {
        "anchor": "The finite temperature QCD using 2+1 flavors of domain wall fermions at\n  N_t = 8: We study the region of the QCD phase transition using 2+1 flavors of domain\nwall fermions (DWF) and a $16^3 \\times 8$ lattice volume with a fifth dimension\nof $L_s = 32$. The disconnected light quark chiral susceptibility, quark number\nsusceptibility and the Polyakov loop suggest a chiral and deconfining crossover\ntransition lying between 155 and 185 MeV for our choice of quark mass and\nlattice spacing. In this region the lattice scale deduced from the Sommer\nparameter $r_0$ is $a^{-1} \\approx 1.3$ GeV, the pion mass is $\\approx 300$ MeV\nand the kaon mass is approximately physical. The peak in the chiral\nsusceptibility implies a pseudo critical temperature $T_c = 171(10)(17)$ MeV\nwhere the first error is associated with determining the peak location and the\nsecond with our unphysical light quark mass and non-zero lattice spacing. The\neffects of residual chiral symmetry breaking on the chiral condensate and\ndisconnected chiral susceptibility are studied using several values of the\nvalence $L_s$.",
        "positive": "The Spatial String Tension in the Deconfined Phase of the\n  (3+1)-Dimensional SU(2) Gauge Theory: We present results of a detailed investigation of the temperature dependence\nof the spatial string tension in SU(2) gauge theory. We show, for the first\ntime, that the spatial string tension is scaling on the lattice and thus is\nnon-vanishing in the continuum limit. It is temperature independent below Tc\nand rises rapidly above. For temperatures larger than 2Tc we find a scaling\nbehaviour consistent with sigma_s(T) = 0.136(11) g^4(T) T^2, where g(T) is the\n2-loop running coupling constant with a scale parameter determined as Lambda_T\n= 0.076(13) Tc."
    },
    {
        "anchor": "Phase structure and monopoles in U(1) gauge theory: We investigate the phase structure of pure compact U(1) lattice gauge theory\nin 4 dimensions with the Wilson action supplemented by a monopole term. To\novercome the suppression of transitions between the phases in the simulations\nwe make the monopole coupling a dynamical variable. We determine the phase\ndiagram and find that the strength of the first order transition decreases with\nincreasing weight of the monopole term, the transition thus ultimately getting\nof second order. After outlining the appropriate topological characterization\nof networks of currents lines, we present an analysis of the occurring monopole\ncurrents which shows that the phases are related to topological properties.",
        "positive": "Gradient Flow Analysis on MILC HISQ Ensembles: We report on a preliminary scale determination with gradient-flow techniques\non the $N_f = 2 + 1 + 1$ HISQ ensembles generated by the MILC collaboration.\nThe ensembles include four lattice spacings, ranging from 0.15 to 0.06 fm, and\nboth physical and unphysical values of the quark masses. The scales\n$\\sqrt{t_0}/a$ and $w_0/a$ are computed using Symanzik flow and the cloverleaf\ndefinition of $\\langle E \\rangle$ on each ensemble. Then both scales and the\nmeson masses $aM_\\pi$ and $aM_K$ are adjusted for mistunings in the charm mass.\nUsing a combination of continuum chiral perturbation theory and a Taylor series\nansatz in the lattice spacing, the results are simultaneously extrapolated to\nthe continuum and interpolated to physical quark masses. Our preliminary\nresults are $\\sqrt{t_0} = 0.1422(7)$fm and $w_0 = 0.1732(10)$fm. We also find\nthe continuum mass-dependence of $w_0$."
    },
    {
        "anchor": "Heavy-Light Matrix Elements with the Wilson Quark Action: Status report is made of our quenched study of heavy-light matrix elements\nemploying the Wilson quark action for heavy quark. Results obtained up to now\nwith 200 configurations at $\\beta=6.1$ on a $24^3\\times64$ lattice and with 100\nconfigurations at $\\beta=6.3$ on a $32^3 \\times80$ lattice suggest that the\npseudoscalar decay constant varies little over this range of $\\beta$ in both\ncharm and bottom regions. Results for the $B$ parameter are also reported.",
        "positive": "Berezinskii-Kosterlitz-Thouless transition in lattice Schwinger model\n  with one flavor of Wilson fermion: We have made a detailed study of the phase structure for lattice Schwinger\nmodel with one flavor of Wilson fermion on the $(m,g)$ plane. For numerical\ninvestigation, we develop a decorated tensor renormalization method for lattice\ngauge theories with fermions incorporating the Grassmann tensor\nrenormalization. Our algorithm manifestly preserves rotation and reflection\nsymmetries. We find not only a parity-broken phase but also a\nBerezinskii-Kosterlitz-Thouless (BKT) transition by evaluating the central\ncharge and an expectation value of a projection operator into the parity-odd\nsubspace. The BKT phase boundaries converge into the degenerated doubler pole\n$(m,g)=(-2,0)$, while the parity-breaking transition line ends at the physical\npole $(m,g)=(0,0)$. In addition, our analysis of scaling dimensions indicates\nthat a conformal field theory with $\\mathrm{SU}(2)$ symmetry arises on the line\nof $m=-2$."
    },
    {
        "anchor": "Running coupling of the sextet composite Higgs model: The scale-dependent renormalized coupling of SU(3) gauge theory coupled to Nf\n= 2 flavors of massless Dirac flavors in the sextet representation is presented\nin the range 0 < g^2 < 6.5. This range includes the location where the\nbeta-function turns zero in the MSbar scheme to 3-loop and 4-loop\napproximations, however our non-perturbative result shows a monotonically\nincreasing beta-function. Our lattice calclulations are carried out at several\nlattice spacings allowing for a controlled continuum extrapolation. We also\ncomment on a recent similar calculation by Hasenfratz tet al.",
        "positive": "Effects of the anomaly on the QCD chiral phase transition: We study a lattice field theory described by two flavors of massless\nstaggered fermions interacting with U(1) gauge fields in the strong coupling\nlimit. We show that the lattice model has a $SU(2)\\times SU(2)\\times U(1)$\nchiral symmetry and can be used to model the two-flavor QCD chiral phase\ntransition in the absence of the anomaly. It is also possible to add a coupling\nto this model which breaks the chiral symmetry to $SU(2)\\times SU(2)$ and thus\nmimics the effects of the anomaly in two-flavor QCD. We construct an efficient\ndirected loop algorithm to study such a model. We show that the chiral phase\ntransition in our model is first order in the absence of the anomaly, while it\nbecomes second order with O(4) exponents when the anomaly is turned on."
    },
    {
        "anchor": "Non-perturbative plaquette in 3d pure SU(3): We present a determination of the elementary plaquette and, after the\nsubsequent ultraviolet subtractions, of the finite part of the gluon\ncondensate, in lattice regularization in three-dimensional pure SU(3) gauge\ntheory. Through a change of regularization scheme to MSbar and a matching back\nto full four-dimensional QCD, this result determines the first non-perturbative\ncontribution in the weak-coupling expansion of hot QCD pressure.",
        "positive": "Heavy-Meson Spectrum Tests of the Oktay--Kronfeld Action: We present heavy-meson spectrum results obtained using the Oktay--Kronfeld\n(OK) action on MILC asqtad lattices. The OK action was designed to improve the\nheavy-quark action of the Fermilab formulation, such that heavy-quark\ndiscretization errors are reduced. The OK action includes dimension-6 and -7\noperators necessary for tree-level matching to QCD through order\n$\\mathrm{O}(\\Lambda^3/m_Q^3)$ for heavy-light mesons and $\\mathrm{O}(v^6)$ for\nquarkonium, or, equivalently, through $\\mathrm{O}(a^2)$ with some\n$\\mathrm{O}(a^3)$ terms with Symanzik power counting. To assess the\nimprovement, we extend previous numerical tests with heavy-meson masses by\nanalyzing data generated on a finer ($a \\approx 0.12\\;$fm) lattice with the\ncorrect tadpole factors for the $c_5$ term in the action. We update the\nanalyses of the inconsistency parameter and the hyperfine splittings for the\nrest and kinetic masses."
    },
    {
        "anchor": "Dressed Wilson loops as dual condensates in response to magnetic fields: We introduce dressed Wilson loops as a novel confinement observable. It\nconsists of closed planar loops of arbitrary geometry but fixed area and its\nexpectation values decay with the latter. The construction of dressed Wilson\nloops is based on chiral condensates in response to magnetic (and electric)\nfields, thus linking different physical concepts. We present results for\ngeneralized condensates and dressed Wilson loops on dynamical lattice\nconfigurations and confirm the agreement with conventional Wilson loops in the\nlimit of large probe mass. We comment on the renormalization of dressed Wilson\nloops.",
        "positive": "An object oriented code for simulating supersymmetric Yang--Mills\n  theories: Discretization of supersymmetric Yang--Mills (SYM) theories is an old problem\nin lattice field theory. It has resisted solution until recently when new ideas\ndrawn from orbifold constructions and topological field theories have been\nbrought to bear on the question. The result has been the creation of a new\nclass of lattice gauge theories in which the lattice action is invariant under\none or more supersymmetries. The resultant theories are local, free of doublers\nand also possess exact gauge-invariance. In principle they form the basis for a\ntruly non-perturbative definition of the continuum SYM theories. In the\ncontinuum limit they lead to a version of the Yang-Mills theory formulated in\nterms of {\\it twisted} fields. In this paper, we briefly review these ideas and\nthen go on to describe the details of a C++ code, which can be used to simulate\nthese theories. We sketch the design of the code, with particular emphasis\nbeing placed on SYM theories with $\\mathcal{N}=2$ in two dimensions and\n$\\mathcal{N}=4$ in three and four dimensions, making one-to-one comparisons\nbetween the essential components of the SYM theories and their corresponding\ncounterparts appearing in the simulation"
    },
    {
        "anchor": "Topological terms in abelian lattice field theories: In this contribution we revisit the lattice discretization of the topological\ncharge for abelian lattice field theories. The construction departs from an\ninitially non-compact discretization of the gauge fields and after absorbing\n$2\\pi$ shifts of the gauge fields leads to a generalized Villain action that\nalso includes the topological term. The topological charge in two, as well as\nin four dimensions can be expressed in terms of only the integer-valued Villain\nvariables. We test various properties of the topological charge and in\nparticular analyze the index theorem in two dimensions and discuss the Witten\neffect in 4-d. As an application of our formulation we present results from a\nsimulation of the 2-d U(1) gauge Higgs model at vacuum angle $\\theta = \\pi$,\nwhere we use a suitable worldline/worldsheet representation to overcome the\ncomplex action problem at non-zero $\\theta$.",
        "positive": "Hadronic coupling constants in lattice QCD: We report on calculations of the hadronic coupling constants $g_{\\rho\\pi\\pi}$\nand $g_{nn\\pi}$ based on lattice QCD with four flavors of dynamical staggered\nfermions. By computing 2--point and 3--point Green's functions we have been\nable to determine these coupling constants ab initio from QCD; the results are\ncompatible with the experimental values."
    },
    {
        "anchor": "$B$ Decay Constants from NRQCD with Dynamical Fermions: We present a lattice investigation of the heavy-light meson decay constants\nusing Wilson light quarks and NRQCD heavy quarks, partially including the\neffects of dynamical sea quarks. We calculate the pseudoscalar and vector decay\nconstants over a wide range in heavy quark mass and are able to perform a\ndetailed analysis of heavy quark symmetry. We find consistency between the\nextrapolation of the NRQCD results and the static case, as expected. We find\nthe slope of the decay constants with $1/M$ is significantly larger than naive\nexpectations and the results of previous lattice calculations. For the first\ntime we extract the non-perturbative coefficients of the slope arising from the\n$O(1/M)$ heavy quark interactions separately and show the kinetic energy of the\nheavy quark is dominant and responsible for the large slope. In addition, we\nfind that significant systematic errors remain in the decay constant extracted\naround the $B$ meson mass due to truncating the NRQCD series at $O(1/M)$. We\nestimate the higher order contributions to $f_B$ are approximately $20\\%$;\nroughly the same size as the systematic errors introduced by using the Wilson\naction for light quarks.",
        "positive": "Embedding Z(3) in SU(3): We consider the design of a non-local MonteCarlo algorithm for $SU(3)$\nlattice systems according to the idea of {\\em embedding} the degrees of freedom\ncorresponding to the center of the group $Z(3)$. As a crucial ingredient to\nreach this goal, we present a practical implementation of a cluster algorithm\nfor $Z(3)$ systems with general random pair interaction."
    },
    {
        "anchor": "Fast Partitioning of Pauli Strings into Commuting Families for\n  Expectation Value Measurements of Dense Operators: The cost of measuring quantum expectation values of an operator can be\nreduced by grouping the Pauli string ($SU(2)$ tensor product) decomposition of\nthe operator into maximally commuting sets. We detail an algorithm, presented\nin [1], to partition the full set of $m$-qubit Pauli strings into the minimal\nnumber of commuting families, and benchmark the performance with dense\nHamiltonians on IBM hardware. Here we also compare how our method scales\ncompared to graph-theoretic techniques for the generally commuting case.",
        "positive": "Topology and index theorem with a generalized Villain lattice action --\n  a test in 2d: Using 2-d U(1) lattice gauge theory we study two definitions of the\ntopological charge constructed from a generalized Villain action and analyze\nthe implementation of the index theorem based on the overlap Dirac operator.\nOne of the two definitions expresses the topological charge as a sum of the\nVillain variables and treats charge conjugation symmetry exactly, making it\nparticularly useful for studying related physics. Our numerical analysis\nestablishes that for both topological charge definitions the index theorem\nbecomes exact quickly towards the continuum limit."
    },
    {
        "anchor": "Lambda(1405) and Negative-Parity Baryons in Lattice QCD: We review briefly recent studies of the Lambda(1405) spectrum in Lattice QCD.\nOrdinary three-quark pictures of the Lambda(1405) in quenched Lattice QCD fail\nto reproduce the mass of the experimental value, which seems to support the\npenta-quark picture for the Lambda(1405) such as a Kbar-N molecule-like state.\nIt is also noted that the present results suffer from relatively large\nsystematic uncertainties coming from the finite volume effect, the chiral\nextrapolation and the quenching effect.",
        "positive": "On the spectrum of mesons in quenched $Sp(2N)$ gauge theories: We report the findings of our extensive study of the spectra of flavoured\nmesons in lattice gauge theories with symplectic gauge group and fermion matter\ncontent treated in the quenched approximation. For the $Sp(4)$, $Sp(6)$, and\n$Sp(8)$ gauge groups, the (Dirac) fermions transform in either the fundamental,\nor the 2-index, antisymmetric or symmetric, representations. This study sets\nthe stage for future precision calculations with dynamical fermions in the low\nmass region of lattice parameter space. Our results have potential\nphenomenological applications ranging from composite Higgs models, to top\n(partial) compositeness, to dark matter models with composite, strong-coupling\ndynamical origin. Having adopted the Wilson flow as a scale-setting procedure,\nwe apply Wilson chiral perturbation theory to extract the continuum and\nmassless limits for the observables of interest. The resulting measurements are\nused to perform a simplified extrapolation to the large-$N$ limit, hence\ndrawing a preliminary connection with gauge theories with unitary groups. We\nconclude with a brief discussion of the Weinberg sum rules."
    },
    {
        "anchor": "Multicomponent gauge-Higgs models with discrete Abelian gauge groups: We consider a variant of the charge-Q compact Abelian-Higgs model, in which\nan Nf-dimensional complex vector is coupled with an Abelian Z_q gauge field.\nFor Nf=2 and Q=1 we observe several transition lines that belong to the O(4),\nO(3), and O(2) vector universality classes, depending on the symmetry breaking\npattern at the transition. The universality class is independent of $q$ as long\nas q>=3. The universality class of the transition is uniquely determined by the\nbehavior of the scalar fields; gauge fields do not play any role. We also\ninvestigate the system for Nf=15 and Q=2. In the presence of U(1) gauge fields,\nthe system undergoes transitions associated with charged fixed points of the\nAbelian-Higgs field theory. These continuous transitions turn into first-order\nones when the U(1) gauge fields are replaced by the discrete Z_q fields: in the\npresent compact model charged transitions appear to be very sensitive to the\nnature of the gauge fields",
        "positive": "Recent progress on QCD inputs for axion phenomenology: The properties of the QCD axion are strictly related to the dependence of\nstrong interactions on the topological parameter theta. We present a\ndetermination of the topological properties of QCD for temperatures up to\naround 600 MeV, obtained by lattice QCD simulations with 2+1 flavors and\nphysical quark masses. Numerical results for the topological susceptibility,\nwhen compared to instanton gas computations, differ both in size and in the\ntemperature dependence. We discuss the implications of such findings for axion\nphenomenology, also in comparison to similar studies in the literature, and the\nprospects for future investigations."
    },
    {
        "anchor": "Scalar Quarkonium Masses and Mixing with the Lightest Scalar Glueball: We evaluate the continuum limit of the valence (quenched) approximation to\nthe mass of the lightest scalar quarkonium state, for a range of different\nquark masses, and to the mixing energy between these states and the lightest\nscalar glueball. Our results support the interpretation of $f_0(1710)$ as\ncomposed mainly of the lightest scalar glueball.",
        "positive": "Free-form Smeared Bottomonium Correlation Functions: Gauge-invariant sources with a hydrogen wave function shape are constructed\nfor bottomonium two-point correlation functions using the free-form smearing\ntechnique. The bottomonium spectrum, including a first lattice result for the\nD-wave first-excited state, is extracted from free-form smeared correlation\nfunctions. Results are compared with conventional smearing techniques and\nfree-form smearing is found to have the advantage of reduced statistical\nerrors."
    },
    {
        "anchor": "Scalar meson in dynamical and partially quenched two-flavor QCD: lattice\n  results and chiral loops: This is an exploratory study of the lightest non-singlet scalar $q\\bar q$\nstate on the lattice with two dynamical quarks. Domain Wall fermions are used\nfor both sea and valence quarks on a 16^3*32 lattice with an inverse lattice\nspacing of 1.7 GeV. We extract the scalar meson mass 1.58(34) GeV from the\nexponential time-dependence of the dynamical correlators with $m_{val}=m_{sea}$\nand N_f=2. Since this statistical error-bar from dynamical correlators is\nrather large, we analyze also the partially quenched lattice correlators with\n$m_{val}$ not equal $m_{sea}$. They are positive for $m_{val}>=m_{sea}$ and\nnegative for $m_{val}<m_{sea}$. In order to understand this striking effect of\npartial quenching, we derive the scalar correlator within the Partially\nQuenched ChPT and find it describes lattice correlators well. The leading\nunphysical contribution in Partially Quenched ChPT comes from the exchange of\nthe two pseudoscalar fields and is also positive for $m_{val}>=m_{sea}$ and\nnegative for $m_{val}<m_{sea}$ at large t. After the subtraction of this\nunphysical contribution from the partially quenched lattice correlators, the\ncorrelators are positive and exponentially falling. The resulting scalar meson\nmass 1.51(19) GeV from the partially quenched correlators is consistent with\nthe dynamical result and has appreciably smaller error-bar.",
        "positive": "Grand Canonical Partition Function of a 2-dimensional Hubbard Model: We present a new technique for a numerical analysis of the phase structure of\nthe 2D Hubbard model as a function of the hole chemical potential. The grand\ncanonical partition function for the model is obtained via Monte Carlo\nsimulations. The dependence of the hole occupation number on the chemical\npotential and the temperature is evaluated. These calculations, together with a\nstudy of the Yang-Lee zeros of the grand canonical partition function, show\nevidence of a phase transition at zero temperature and particle density below\nhalf-filling. The binding energy of a pair of holes is calculated in the low\ntemperature regime and the possibility for pairing is explored."
    },
    {
        "anchor": "K_l3 form factor with two-flavors of dynamical domain-wall quarks: We report on our calculation of K \\to \\pi vector form factor by numerical\nsimulations of two-flavor QCD on a 16^3x32x12 lattice at a \\simeq 0.12 fm using\ndomain-wall quarks and DBW2 glue. Our preliminary result at a single sea quark\nmass correponding to m_PS/m_V \\simeq 0.53 shows a good agreement with previous\nestimate in quenched QCD and that from a phenomenological model.",
        "positive": "Speeding up the Hybrid-Monte-Carlo algorithm for dynamical fermions: We propose a modification of the Hybrid-Monte-Carlo algorithm that allows for\na larger step-size of the integration scheme at constant acceptance rate. The\nkey ingredient is the splitting of the pseudo-fermion action into two parts. We\ntest our proposal at the example of the two-dimensional lattice Schwinger model\nand four-dimensional lattice QCD with two degenerate flavours of Wilson-\nfermions."
    },
    {
        "anchor": "Toward solving the sign problem with path optimization method: We propose a new approach to circumvent the sign problem in which the\nintegration path is optimized to control the sign problem. We give a trial\nfunction specifying the integration path in the complex plane and tune it to\noptimize the cost function which represents the seriousness of the sign\nproblem. We call it the path optimization method. In this method, we do not\nneed to solve the gradient flow required in the Lefschetz-thimble method and\nthen the construction of the integration-path contour arrives at the\noptimization problem where several efficient methods can be applied. In a\nsimple model with a serious sign problem, the path optimization method is\ndemonstrated to work well; the residual sign problem is resolved and precise\nresults can be obtained even in the region where the global sign problem is\nserious.",
        "positive": "Effects of the anomaly on the two-flavor QCD chiral phase transition: We use strongly coupled lattice QED with two flavors of massless staggered\nfermions to model the physics of pions in two-flavor massless QCD. Our model\nhas the right chiral symmetries and can be studied efficiently with cluster\nalgorithms. In particular we can tune the strength of the QCD anomaly and thus\nstudy its effects on the chiral phase transition. Our study confirms the widely\naccepted view point that the chiral phase transition is first order in the\nabsence of the anomaly. Turning on the anomaly weakens the transition and turns\nit second order at a critical anomaly strength. The anomaly strength at the\ntricritical point is characterized using $r = (M_{\\eta'}-M_{\\pi})/\\rho_{\\eta'}$\nwhere $M_{\\eta'}, M_{\\pi}$ are the screening masses of the anomalous and\nregular pions and $\\rho_{\\eta'}$ is the mass-scale that governs the low energy\nfluctuations of the anomalous symmetry. We estimate that $r \\sim 7 $ in our\nmodel. This suggests that a strong anomaly at the two-flavor QCD chiral phase\ntransition is necessary to wash out the first order transition."
    },
    {
        "anchor": "Critical correlators of three-dimensional gauge theories at finite\n  temperature: exact results from universality: According to the Svetitsky-Yaffe conjecture, a three-dimensional gauge theory\nundergoing a continuous deconfinement transition is in the same universality\nclass as a two-dimensional statistical model with order parameter taking values\nin the center of the gauge group. This allows us to use conformal field theory\ntechniques to evaluate exactly various correlation functions at the critical\npoint. In particular, we show that the plaquette operator of the gauge theory\nis mapped into the energy operator of the dimensionally reduced model. The\nplaquette expectation value in presence of static sources for three-dimensional\nSU(2) and SU(3) theories at the deconfinement temperature can be exactly\nevaluated, providing some new insight about the structure of the color flux\ntube in mesons and baryons.",
        "positive": "B meson B-parameters and the decay constant in two-flavor dynamical QCD: We present a two-flavor dynamical QCD calculation of the B meson B parameters\nand decay constant. We use NRQCD for heavy quark and the nonperturbatively\nO(a)-improved Wilson action for light quark at $\\beta$=5.2 on a $20^3\\times 48$\nlattice. We confirm that the sea quark effect increases the heavy-light decay\nconstant, while estimate of its magnitude depends significantly on the fitting\nform in the chiral extrapolation. For the B parameters, on the other hand, we\ndo not find a significant sea quark effect. The chiral extrapolation with\nlogarithmic term is examined for both quantities and compared with the\nprediction of ChPT."
    },
    {
        "anchor": "Asymptotic behavior of Nambu-Bethe-Salpeter wave functions for\n  multi-particles in quantum field theories: We derive asymptotic behaviors of the Nambu-Bethe-Salpeter (NBS) wave\nfunction at large space separations for systems with more than 2 particles in\nquantum field theories. To deal with $n$-particles in the center of mass flame\ncoherently, we introduce the Jacob coordinates of $n$ particles and then\ncombine their $3(n-1)$ coordinates into the one spherical coordinate in\n$D=3(n-1)$ dimensions. We parametrize on-shell $T$-matrix for $n$-particle\nsystem of scalar fields at low energy, using the unitarity constraint of the\n$S$-matrix. We then express asymptotic behaviors of the NBS wave function for\n$n$ particles at low energy, in terms of parameters of $T$-matrix, and show\nthat the NBS wave function carry the information of $T$-matrix such as phase\nshifts and mixing angles of the $n$-particle system in its own asymptotic\nbehavior, so that the NBS wave function can be considered as the scattering\nwave of $n$-particles in quantum mechanics. This property is one of the\nessential ingredients of the HAL QCD scheme to define \"potential\" from the NBS\nwave function in quantum field theories such as QCD. Our results, together with\nan extension to systems with spin 1/2 particles, justify the HAL QCD's\ndefinition of potentials for 3 or more nucleons(baryons) in terms the NBS wave\nfunctions.",
        "positive": "The non-zero baryon number formulation of QCD: We discuss the non-zero baryon number formulation of QCD in the quenched\nlimit at finite temperature. This describes the thermodynamics of gluons in the\nbackground of static quark sources. Although a sign problem remains in this\ntheory, our simulation results show that it can be handled quite well\nnumerically. The transition region gets shifted to smaller temperatures and the\ntransition region broadens with increasing baryon number. Although the action\nis in our formulation explicitly Z(3) symmetric the Polyakov loop expectation\nvalue becomes non-zero already in the low temperature phase and the heavy quark\npotential gets screened at non-vanishing number density already this phase."
    },
    {
        "anchor": "Tuning Fermilab Heavy Quarks in 2+1 Flavor Lattice QCD with Application\n  to Hyperfine Splittings: We report the non-perturbative tuning of parameters--- kappa_c, kappa_b, and\nkappa_crit ---that determine the heavy-quark mass in the Fermilab action. This\nrequires the computation of the masses of Ds^(*) and Bs^(*) mesons comprised of\na Fermilab heavy quark and a staggered light quark. Additionally, we report the\nhyperfine splittings for Ds and Bs mesons as a cross-check of our simulation\nand analysis methods. We find a splitting of 145 +/- 15 MeV for the Ds system\nand 40 +/- 9 MeV for the Bs system. These are in good agreement with the\nParticle Data Group average values of 143.9 +/- 0.4 MeV and 46.1 +/- 1.5 MeV,\nrespectively. The calculations are carried out with the MILC 2+1 flavor gauge\nconfigurations at three lattice spacings $a$ approximately 0.15, 0.12, and 0.09\nfm.",
        "positive": "Accessing High Momentum States In Lattice QCD: Two measures are defined to evaluate the coupling strength of smeared\ninterpolating operators to hadronic states at a variety of momenta. Of\nparticular interest is the extent to which strong overlap can be obtained with\nindividual high-momentum states. This is vital to exploring hadronic structure\nat high momentum transfers on the lattice and addressing interesting phenomena\nobserved experimentally. We consider a novel idea of altering the shape of the\nsmeared operator to match the Lorentz contraction of the probability\ndistribution of the high-momentum state, and show a reduction in the relative\nerror of the two-point function by employing this technique. Our most important\nfinding is that the overlap of the states becomes very sharp in the smearing\nparameters at high momenta and fine tuning is required to ensure strong overlap\nwith these states."
    },
    {
        "anchor": "Numerical study of the Kugo-Ojima criterion and the Gribov problem in\n  the Landau gauge: The Kugo-Ojima color confinement criterion, which is based on the BRST\nsymmetry of the continuum QCD is numerically tested by the lattice Landau gauge\nsimulation. We first discuss the Gribov copy problem and the BRST symmetry on\nthe lattice. The lattice Landau gauge can be formulated with options of the\ngauge field definition, U(link)-linear type or log U type. The Kugo-Ojima\nparameter u^a_b which is expected to be -1^a_b in the continuum theory is found\nto be -0.7*1^a_b in the strong coupling region, and the magnitude is a little\nless in the weak coupling region in log U type simulation. Those values are\nweakened even further in U-linear type. The horizon function defined by\nZwanziger is evaluated in both types of gauge field and compared. The horizon\nfunction in the log U version is larger than the other, but in the weak\ncoupling region, the expectation value of the horizon function is suggested to\nbe zero or negative.",
        "positive": "Numerical study of the mass spectrum in the 2D O(3) sigma model with a\n  theta term: It has been conjectured that the mass spectrum of the O(3) non-linear sigma\nmodel with a theta term in 2 dimensions may possess an excited state, which\ndecays when theta is lowered from pi below a critical value. Since the direct\nnumerical investigation of the model is prevented by a sign problem, we try to\ninfer some information on the mass spectrum at real theta by studying the model\nat imaginary theta via analytic continuation. A modified Swendsen-Wang cluster\nalgorithm has been introduced to simulate the model with the theta term."
    },
    {
        "anchor": "Generalized susceptibilities along the phase boundary of the\n  three-dimensional, three-state Potts model: Through the Monte Carlo simulation of the three-dimensional, three-state\nPotts model, which is a paradigm of finite-temperature pure gauge QCD, we study\nthe fluctuations of generalized susceptibilities near the temperatures of\nexternal fields of first-, second-order phase transitions and crossover.\nSimilar peak-like fluctuation appears in the second order susceptibility at\nthree given external fields. Oscillation-like fluctuation appears in the third\nand fourth order susceptibilities. We find that these non-monotonic\nfluctuations are not only associated with the second-order phase transition,\nbut also the first-order one and crossover in a system of finite-size. We\nfurther present the finite-size scaling analysis of the second and fourth order\nsusceptibilities, respectively. The exponent of the scaling characterizes the\norder of the transitions, or the crossover.",
        "positive": "Normalizing Flows and the Real-Time Sign Problem: Normalizing flows have recently been applied to the problem of accelerating\nMarkov chains in lattice field theory. We propose a generalization of\nnormalizing flows that allows them to applied to theories with a sign problem.\nThese complex normalizing flows are closely related to contour deformations\n(i.e. the generalized Lefschetz thimble method), which been applied to sign\nproblems in the past. We discuss the question of the existence of normalizing\nflows: they do not exist in the most general case, but we argue that exact\nnormalizing flows are likely to exist for many physically interesting problems,\nincluding cases where the Lefschetz thimble decomposition has an intractable\nsign problem. Finally, normalizing flows can be constructed in perturbation\ntheory. We give numerical results on their effectiveness across a range of\ncouplings for the Schwinger-Keldysh sign problem associated to a real scalar\nfield in $0+1$ dimensions."
    },
    {
        "anchor": "Light Quenched Hadron Spectrum and Decay Constants on different Lattices: We present a study of ${\\cal O}(2000)$ (quenched) lattice configurations from\nthe APE collaboration, for $6.0\\le\\beta\\le 6.4$ using both the Wilson and the\nSW-Clover fermion action. We determine the light hadronic spectrum and meson\ndecay constants. We extract the inverse lattice spacing using data at the\nsimulated values of the quark mass. We find an agreement with the experimental\ndata of $\\sim 5%$ for mesonic masses and $\\sim 10%-15%$ for baryonic masses and\npseudoscalar decay constants. A larger deviation is present for the vector\ndecay constants.",
        "positive": "Exotic Quantum Critical Points with Staggered Fermions: We study two flavors of massless staggered fermions interacting via an\non-site four-fermion inter- action and argue that the model contains an exotic\nquantum critical point separating the perturba- tive massless phase from a\nmassive fermion phase at strong couplings where the fermion bilinear condensate\nremains zero. We believe that no spontaneous symmetry breaking occurs at the\ntran- sition. We have extensive calculations in three Euclidian dimensions that\nare consistent with the existence of a single second order phase transition\nseparating the two phases. Although mean field theory suggests that this\ntransition will turn first order at sufficiently large number of dimensions,\npreliminary results suggest that the transition remains second order in\nfour-dimensions."
    },
    {
        "anchor": "Locality properties of Neuberger's lattice Dirac operator: The gauge covariant lattice Dirac operator D which has recently been proposed\nby Neuberger satisfies the Ginsparg-Wilson relation and thus preserves chiral\nsymmetry. The operator also avoids a doubling of fermion species, but its\nlocality properties are not obvious. We now prove that D is local (with\nexponentially decaying tails) if the gauge field is sufficiently smooth at the\nscale of the cutoff. Further analytic and numerical studies moreover suggest\nthat the locality of the operator is in fact guaranteed under far more general\nconditions.",
        "positive": "Sensitivity of the Polyakov loop and related observables to chiral\n  symmetry restoration: While the Polyakov loop is an order parameter of the deconfinement transition\nin the heavy quark mass regime of QCD, its sensitivity to the deconfinement of\nlight, dynamical quarks in QCD is not apparent. On the other hand, the quark\nmass dependence of the Polyakov loop is sensitive to the appearance of a chiral\nphase transition. Using lattice QCD calculations in the staggered fermion\ndiscretization scheme at finite values of the lattice spacing, $aT = 1/8$, we\nshow here, for the first time, that the Polyakov loop expectation value, and\nthe heavy quark free energy extracted from it, behave like energy-like\nobservables in the vicinity of the chiral phase transition temperature $T_c$.\nConsistent with scaling behavior of energy-like observables in the 3-$d$, O(2)\nuniversality class, the quark mass derivatives diverge in the chiral limit at\n$T_c$ while the temperature derivatives stay finite. The latter will develop a\ncharacteristic spike at $T_c$. This, however, may be resolved only in\ncalculations with quark masses being two orders of magnitude smaller than those\ncurrently accessible in lattice QCD calculations."
    },
    {
        "anchor": "Spinorial flux tubes in SO(N) gauge theories in 2+1 dimensions: We investigate whether one can observe in SO(3) and SO(4) (lattice) gauge\ntheories the presence of spinorial flux tubes, i.e. ones that correspond to the\nfundamental representation of SU(2); and similarly for SO(6) and SU(4). We do\nso by calculating the finite volume dependence of the JP=2+ glueball in 2+1\ndimensions, using lattice simulations. We show how this provides strong\nevidence that these SO(N) gauge theories contain states that are composed of\npairs of (conjugate) winding spinorial flux tubes, i.e. ones that are in the\n(anti)fundamental of the corresponding SU(N') gauge theories. Moreover, these\ntwo flux tubes can be arbitrarily far apart. This is so despite the fact that\nthe fields that are available in the SO(N) lattice field theories do not appear\nto allow us to construct operators that project onto single spinorial flux\ntubes.",
        "positive": "Shifted unitary orthogonal methods for the overlap inversion: In this work we compare the convergence of the shifted unitary orthogonal\nmethod (SUOM) and different Krylov subspace solvers for propagator computations\nwith overlap fermions. We show that the SUOM algorithm performs similarly to\nthe shifted unitary minimal residual method (SUMR) with the latter converging\nslightly faster. When the geometric optimality is applied to SUOM we get e new\nalgorithm which is faster than SUMR."
    },
    {
        "anchor": "Towards reduction of autocorrelation in HMC by machine learning: In this paper we propose new algorithm to reduce autocorrelation in Markov\nchain Monte-Carlo algorithms for euclidean field theories on the lattice. Our\nproposing algorithm is the Hybrid Monte-Carlo algorithm (HMC) with restricted\nBoltzmann machine. We examine the validity of the algorithm by employing the\nphi-fourth theory in three dimension. We observe reduction of the\nautocorrelation both in symmetric and broken phase as well. Our proposing\nalgorithm provides consistent central values of expectation values of the\naction density and one-point Green's function with ones from the original HMC\nin both the symmetric phase and broken phase within the statistical error. On\nthe other hand, two-point Green's functions have slight difference between one\ncalculated by the HMC and one by our proposing algorithm in the symmetric\nphase. Furthermore, near the criticality, the distribution of the one-point\nGreen's function differs from the one from HMC. We discuss the origin of\ndiscrepancies and its improvement.",
        "positive": "The Lattice Schrodinger Functional and the Background Field Effective\n  Action: We propose a new method that by using the lattice Schr\\\"odinger functional\nallows to investigate the effective action for external background fields in\nlattice gauge theories. We show that this method gives sensible results for the\ncase of four-dimensional U(1) gauge theory in an external constant magnetic\nfield."
    },
    {
        "anchor": "Phase of the Fermion Determinant at Nonzero Chemical Potential: We show that in the microscopic domain of QCD (also known as the\n$\\epsilon$-domain) at nonzero chemical potential the average phase factor of\nthe fermion determinant is nonzero for $\\mu < m_\\pi/2$ and is exponentially\nsuppressed for larger values of the chemical potential. This follows from the\nchiral Lagrangian that describes the low-energy limit of the expectation value\nof the phase factor. Explicit expressions for the average phase factor are\nderived using a random matrix formulation of the zero momentum limit of this\nchiral Lagrangian.",
        "positive": "Lattice Constraints on the QCD Chiral Phase Transition at Finite\n  Temperature and Baryon Density: The thermal restoration of chiral symmetry in QCD is known to proceed by an\nanalytic crossover, which is widely expected to turn into a phase transition\nwith a critical endpoint as the baryon density is increased. In the absence of\na genuine solution to the sign problem of lattice QCD, simulations at zero and\nimaginary baryon chemical potential in a parameter space enlarged by a variable\nnumber of quark flavours and quark masses constitute a viable way to constrain\nthe location of a possible non-analytic phase transition and its critical\nendpoint. In this article I review recent progress towards an understanding of\nthe nature of the transition in the massless limit, and its critical\ntemperature at zero density. Combined with increasingly detailed studies of the\nphysical crossover region, current data bound a possible critical point to\n$\\mu_B > 3T$."
    },
    {
        "anchor": "Baryon spectroscopy with spatially improved quark sources: We study baryons on the lattice with a special focus on excited states. For\nthat purpose we construct several interpolators which differ in their Dirac\nstructure. These interpolators are built from Jacobi smeared quarks with\ndifferent widths in order to allow for operators with improved spatial\nwavefunctions. We compute all cross correlations and use the variational method\nto determine which combinations of operators have best overlap with ground and\nexcited states. Our approach yields promising results for the spin-1/2 baryons:\nnucleon, sigma, xi and lambda. For the spin-3/2 baryons, delta and omega, we\nobtain results which are consistent with results of other groups.",
        "positive": "Just how different are SU(2) and SU(3) Landau-gauge propagators in the\n  IR regime?: The infrared behavior of gluon and ghost propagators in Yang-Mills theories\nis of central importance for understanding quark and gluon confinement in QCD.\nWhile simulations of pure SU(3) gauge theory correspond to the physical case in\nthe limit of infinite quark mass, the SU(2) case (i.e. pure two-color QCD) is\nusually employed as a simplification, in the hope that qualitative features be\nthe same as for the SU(3) case. Here we carry out the first comparative study\nof lattice (Landau) propagators for these two gauge groups. Our data were\nespecially produced with equivalent lattice parameters in order to allow a\ncareful comparison of the two cases. We find very good agreement between SU(2)\nans SU(3) propagators, showing that in the IR limit the equivalence of the two\ncases is quantitative, at least down to about 1 GeV. Our results suggest that\nthe infrared behavior of these propagators is independent of the gauge group\nSU(N_c), as predicted by Schwinger-Dyson equations."
    },
    {
        "anchor": "N(N*) and Delta(Delta*) on the lattice: We investigate the mass spectrum of Nucleon and Delta (and its counterparts\nwith strange and charm), and their excited states, in quenched lattice QCD with\nexact chiral symmetry. For each light baryon, we use 23 masses to determine the\ncoefficients of the mass formula in quenched chiral perturbation theory. By\nchiral extrapolation to m_\\pi=135 MeV, we obtain M_N=958(26) MeV,\nM_{N*}=1553(42) MeV, M_{Delta}=1216(32) MeV and M_{Delta*}=1611(17) MeV, which\nare identified with N(939)P_{11},N(1535)S_{11}, Delta(1232)P_{33} and\nDelta(1620)S_{31} respectively. Further, we directly measure the masses of\nOmega^{-}, M_{Omega}=1648(60) MeV, and its excited state, M_{Omega*}=1935(48)\nMeV; as well as the triply charmed baryon Omega_{ccc}^{++},\nM_{Omega_{ccc}^{++}}=4931(22) MeV, and its excited state,\nM_{{\\Omega^{++}_{ccc}}^*}=5185(35) MeV.",
        "positive": "Application of the Coupled Cluster Method to a Hamiltonian Lattice Field\n  Theory: The coupled cluster method has been applied to the eigenvalue problem lattice\nHamiltonian QCD (without quarks) for SU(2) gauge fields in two space\ndimensions.\n  Using a recently presented new formulation and the truncation prescription of\nGuo et al. we were able to compute the ground state and the lowest\n$0^+$-glueball mass up to the sixth order of the coupled cluster expansion.\n  The results show evidence for a ``scaling window'' (i.e. good convergence and\nconstance of dimensionless quantities) around $\\beta=4/g^2 \\approx 3$.\n  A comparison of our results to those of other methods is presented."
    },
    {
        "anchor": "Search for a continuum limit of the PMS phase: Previous studies of a simple four-fermion model with staggered fermions in 3D\nhave shown the existence of an exotic quantum critical point, where one may be\nable to define a continuum limit of the Paramagnetic Strong Phase (or the PMS\nphase). We believe the existence of the critical point suggests a new mechanism\nfor generating fermion masses. In this work we begin the search for this\nquantum critical point in 4D by extending the 3D model to 4D. Unlike in 3D, now\nwe do find evidence for an intermediate spontaneously broken phase (FM phase)\nand are able compute the phase boundaries accurately. In terms of the bare\ncoupling, the width of the intermediate region appears to be quite small.",
        "positive": "Quark propagator with two flavors of O(a)-improved Wilson fermions: We compute the Landau gauge quark propagator from lattice QCD with two\nflavors of dynamical O(a)-improved Wilson fermions. The calculation is carried\nout with lattice spacings ranging from 0.06 fm to 0.08 fm, with quark masses\ncorresponding to pion masses of 420, 290 and 150 MeV, and for volumes of up to\n(4.5fm)^4. Our ensembles allow us to evaluate lattice spacing, volume and quark\nmass effects. We find that the quark wave function which is suppressed in the\ninfrared, is further suppressed as the quark mass is reduced, but the\nsuppression is weakened as the volume is increased. The quark mass function\nM(p^2) shows only a weak volume dependence. Hypercubic artefacts beyond O(a)\nare reduced by applying both cylinder cuts and H4 extrapolations. The H4\nextrapolation shifts the quark wave function systematically upwards but does\nnot perform well for the mass function."
    },
    {
        "anchor": "On behaviour of critical lines near ferrimagnetic phase in Higgs-Yukawa\n  systems: We calculate within a mean-field approximation the slopes of the critical\nlines near the point of appearing the ferrimagnetic phase for the U(1) systems\nin the weak coupling regime. It is demonstrated that the slope of one of the\ncritical line is continuous, while change of the slope of the other depends\nstrongly on the number of the fermion flavours. We also find that in the\nferrimagnetic phase near such a point the magnetization and the staggered\nmagnetization align orthogonally to each other.",
        "positive": "Real time evolution of scalar fields with kernelled Complex Langevin\n  equation: The real time evolution of a scalar field in 0+1 dimensions is investigated\non a complex time contour. The path integral formulation of the system has a\nsign problem, which is circumvented using the Complex Langevin equation.\nMeasurement of the boundary terms allow for the detection of correct results\n(for contours with small real time extents) or incorrect results (at large real\ntime extents), as confirmed by comparison to exact results calculated using\ndiagonalization of the Hamiltonian. We introduce a constant matrix kernel in\nthe Complex Langevin equation, which is optimized with the requirement that\ndistributions of the fields on the complexified manifold remain close to the\nreal manifold. We observe that reachable real times are roughly twice as large\nwith the optimal kernel. We also investigate field dependent kernels\nrepresented by a neural network for a toy model as well as for the scalar\nfield, providing promising first results."
    },
    {
        "anchor": "Phase structure of many flavor lattice QCD at finite temperature: In realistic technicolor models containing many fermions, the electroweak\nbaryogenesis offers a natural scenario for generating baryon number asymmetry.\nOne of the key ingredients is the occurrence of the first order phase\ntransition at finite temperature. As a first step toward the exploration of\nthis possibility on the lattice, we develop an agile method to identify the\ncritical mass for a given Nf, separating the first order and the crossover\ntransition. We explain the outline of our method and demonstrate it by\ndetermining the critical mass of Nf-flavors in the presence of light\ntwo-flavors. It is found that the critical mass becomes larger with Nf.",
        "positive": "Nucleon axial charge from quenched lattice QCD with domain wall fermions\n  and improved gauge action: In our previous DWF calculation with the Wilson gauge action at $\\beta=6.0$\n($a^{-1}\\simeq$ 1.9 GeV) on a $16^3 \\times 32 \\times 16$ lattice, we found that\n$\\Ga$ had a fairly strong dependence on the quark mass. A simple linear\nextrapolation of $\\Ga$ to the chiral limit yielded a value that was almost a\nfactor of two smaller than the experimental one. Here we report our recent\nstudy of this issue. In particular, we investigate possible errors arising from\nfinite lattice volume, especially in the lighter quark mass region. We employ a\nRG-improved gauge action (DBW2), which maintains very good chiral behavior even\non a coarse lattice ($a^{-1}\\simeq$ 1.3 GeV), in order to perform simulations\nat large physical volume ($> (2{\\rm fm})^3$). Our preliminary results suggest\nthat the finite volume effect is significant."
    },
    {
        "anchor": "Nucleon strange quark content from N_f=2+1 lattice QCD with exact chiral\n  symmetry: We calculate the strange quark content of the nucleon in 2+1-flavor lattice\nQCD. Chirally symmetric overlap fermion formulation is used to avoid the\ncontamination from up and down quark contents due to an operator mixing between\nstrange and light scalar operators, \\bar{s}s and \\bar{u}u+\\bar{d}d. At a\nlattice spacing a=0.112(1) fm, we perform calculations at four values of\ndegenerate up and down quark masses, which cover a range of the pion mass M_pi\n\\simeq 300-540 MeV. We employ two different methods: one is a direct method\nwhere we calculate the strange quark content by directly inserting the strange\nscalar operator. The other is an indirect method where the quark content is\nextracted from a derivative of the nucleon mass in terms of the strange quark\nmass. With these two methods we obtain consistent results with each other. Our\nbest estimate f_{T_s}=0.009(15)(16) is in good agreement with our previous\nstudies in two-flavor QCD.",
        "positive": "Topological charge using cooling and the gradient flow: The equivalence of cooling to the gradient flow when the cooling step $n_c$\nand the continuous flow step of gradient flow $\\tau$ are matched is generalized\nto gauge actions that include rectangular terms. By expanding the link\nvariables up to subleading terms in perturbation theory, we relate $n_c$ and\n$\\tau$ and show that the results for the topological charge become equivalent\nwhen rescaling $\\tau \\simeq n_c/({3-15 c_1})$ where $c_1$ is the Symanzik\ncoefficient multiplying the rectangular term. We, subsequently, apply cooling\nand the gradient flow using the Wilson, the Symanzik tree-level improved and\nthe Iwasaki gauge actions to configurations produced with $N_f=2+1+1$ twisted\nmass fermions. We compute the topological charge, its distribution and the\ncorrelators between cooling and gradient flow at three values of the lattice\nspacing demonstrating that the perturbative rescaling $\\tau \\simeq n_c/({3-15\nc_1})$ leads to equivalent results."
    },
    {
        "anchor": "Calculating $B_K$ using HYP staggered fermions: We give an update on our calculation of $B_K$ using HYP-smeared valence\nstaggered quarks. We have results for $B_K$ at tree-level on several coarse\nMILC lattices ($a\\approx 0.12 $fm) and one of the fine lattices ($a\\approx 0.09\n$fm), using 10 light valence quarks ranging down to $m_s^{\\rm phys}/10$. We\nhave generalized staggered chiral perturbation theory to our mixed action\nsetup, and outline the results. We explain our present fitting strategy, and\ngive some preliminary results.",
        "positive": "Field-strength correlators in $SU(2)$ gauge theory: We measure field-strength and their correlators in presence of a static $q\n\\bar q$ pair by numerical simulations. We give an interpretation of these data\nin terms of quadratic and quartic cumulants."
    },
    {
        "anchor": "Pion form factor from 2+1 dynamical flavor lattice QCD using the O(a)\n  improved Wilson-clover quark formalism: We present a status report of our calculation of the electromagnetic form\nfactor of the pion on the PACS-CS gauge field configurations generated using\nIwasaki gauge action and Wilson-clover quark action for 2 + 1 flavors of light\ndynamical quarks. The technique of twiseted boundary conditon is employed to\nexplore the form factor for small momentum transfer. The $q^2$ behavior of the\nform factor and its light quark mass dependence is examined.",
        "positive": "Metadynamics Surfing on Topology Barriers: the $CP^{N-1}$ Case: As one approaches the continuum limit, $QCD$ systems, investigated via\nnumerical simulations, remain trapped in sectors of field space with fixed\ntopological charge. As a consequence the numerical studies of physical\nquantities may give biased results. The same is true in the case of two\ndimensional $CP^{N-1}$ models. In this paper we show that metadynamics, when\nused to simulate $CP^{N-1}$, allows to address efficiently this problem. By\nstudying $CP^{20}$ we show that we are able to reconstruct the free energy of\nthe topological charge $F(Q)$ and compute the topological susceptibility as a\nfunction of the coupling and of the volume. This is a very important physical\nquantity in studies of the dynamics of the $\\theta$ vacuum and of the axion.\nThis method can in principle be extended to $QCD$ applications."
    },
    {
        "anchor": "The mixing of two-pion and vector-meson states using staggered fermions: In this study we employ staggered fermions to calculate the two-pion taste\nsinglet states at rest. Leveraging the Clebsch-Gordan coefficients of the\nsymmetry group associated with staggered fermions, we effectively compute the\n$\\pi\\pi$ contributions to the resting $\\rho$-meson correlator. To discern the\ndistinct energy states involved, we adopt a generalized eigenvalue\nproblem-solving approach. This work will provide insight into the important\nrole played by the two-pion contribution to the anomalous magnetic moment of\nthe muon.\n  In this paper we present our group theoretic considerations and preliminary\nresults on the contribution of two-pion states to the rho meson correlation\nfunction.",
        "positive": "The hadronic contribution to the running of the electromagnetic coupling\n  and the electroweak mixing angle: The electromagnetic coupling $\\alpha$ and the electroweak mixing angle\n$\\theta_{\\mathrm{W}}$ are parameters of the Standard Model (SM) that enter\nprecision SM tests and play a fundamental r\\^ole in beyond SM physics searches.\nTheir values are energy dependent, and non-perturbative hadronic contributions\nare the main source of uncertainty to the theoretical knowledge of the running\nwith energy. We present a lattice study of the leading hadronic contribution to\nthe running of $\\alpha$ and $\\sin^2\\theta_{\\mathrm{W}}$. The former is related\nto the hadronic vacuum polarization (HVP) function of electromagnetic currents,\nand the latter to the HVP mixing of the electromagnetic current with the vector\npart of the weak neutral currents. We use the time-momentum representation\n(TMR) method to compute the HVP on the lattice, estimating both connected and\ndisconnected contributions on $N_{\\mathrm{f}}=2+1$ non-perturbatively\n$O(a)$-improved Wilson fermions ensembles from the Coordinated Lattice\nSimulations (CLS) initiative. The use of different lattice spacings and quark\nmasses allows us to reliably extrapolate the results to the physical point."
    },
    {
        "anchor": "Absolute Measure of Local Chirality and the Chiral Polarization Scale of\n  the QCD Vacuum: The use of the absolute measure of local chirality is championed since it has\na uniform distribution for randomly reshuffled chiral components so that any\ndeviations from uniformity in the associated \"X-distribution\" are directly\nattributable to QCD-induced dynamics. We observe a transition in the\nqualitative behavior of this absolute X-distribution of low-lying eigenmodes\nwhich, we propose, defines a chiral polarization scale of the QCD vacuum.",
        "positive": "$D_{s0}^*(2317)$ Meson and $D$-Meson-Kaon Scattering from Lattice QCD: The scalar meson $D_{s0}^*(2317)$ is found 37(17)MeV below DK threshold in a\nlattice simulation of the $J^P=0^+$ channel using, for the first time, both DK\nas well as $\\bar sc$ interpolating fields. The simulation is done on $N_f=2+1$\ngauge configurations with $m_\\pi\\simeq 156 $MeV, and the resulting\n$M_{D_{s0}^*}-\\tfrac{1}{4}(M_{D_s}+3M_{D_s^*})=266(16)$ MeV is close to the\nexperimental value 241.5(0.8)MeV. The energy level related to the scalar meson\nis accompanied by additional discrete levels due to DK scattering states. The\nlevels near threshold lead to the negative DK scattering length $a_0=-1.33(20)$\nfm that indicates the presence of a state below threshold."
    },
    {
        "anchor": "Performance of machines for lattice QCD simulations: We review the architecture of massively parallel machines used for lattice\nQCD simulations and present benchmarks for the performance of popular\nalgorithms on these platforms. We cover commercial supercomputers, PC clusters,\nand custom-designed machines. We also speculate on future developments.",
        "positive": "Scaling and Eigenmode Tests of the Improved Fat Clover Action: We test a recently proposed improved lattice-fermion action, the fat link\nclover action, examining indicators of pathological small-quark-mass lattice\nartifacts (\"exceptional configurations\") on quenched lattices of spacing 0.12\nfm and studying scaling properties of the light hadron spectrum for lattice\nspacing a=0.09 and 0.16 fm. We show that the action apparently has fewer\nproblems with pathological lattice artifacts than the conventional\nnonperturbatively improved clover action and its spectrum scales just as well."
    },
    {
        "anchor": "Soft dynamics in heavy-light mesons: We compute the radial distributions of the scalar, vector and axial charge\ndensity in the heavy-light mesons. We present the results obtained for both the\nlowest lying static heavy-light mesons as well as for their nearest\nexcitations, with $N_f=2$ dynamical quarks of Wilson (Clover) type. We used\nvarious improvements of the static heavy-quark actions. From these\ndistributions we were able to compute the corresponding charges and their radii\n$< r^2>$, the results of which are also presented.",
        "positive": "The critical equation of state of the three-dimensional O(N)\n  universality class: N>4: We determine the scaling equation of state of the three-dimensional O(N)\nuniversality class, for N=5, 6, 32, 64. The N=5 model is relevant for the SO(5)\ntheory of high-T_c superconductivity, while the N=6 model is relevant for the\nchiral phase transition in two-color QCD with two flavors. We first obtain the\ncritical exponents and the small-field, high-temperature, expansion of the\neffective potential (Helmholtz free energy) by analyzing the available\nperturbative series, in both fixed-dimension and epsilon-expansion schemes.\nThen, we determine the critical equation of state by using a systematic\napproximation scheme, based on polynomial representations valid in the whole\ncritical region, which satisfy the known analytical properties of the equation\nof state, take into account the Goldstone singularities at the coexistence\ncurve and match the small-field, high-temperature, expansion of the effective\npotential. This allows us also to determine several universal amplitude ratios.\nWe also compare our approximate solutions with those obtained in the large-N\nexpansion, up to order 1/N, finding good agreement for N\\gtrsim 32."
    },
    {
        "anchor": "Polyakov loops and spectral properties of the staggered Dirac operator: We study the spectrum of the staggered Dirac operator in SU(2) gauge fields\nclose to the free limit, for both the fundamental and the adjoint\nrepresentation. Numerically we find a characteristic cluster structure with\nspacings of adjacent levels separating into three scales. We derive an\nanalytical formula which explains the emergence of these different spectral\nscales. The behavior on the two coarser scales is determined by the lattice\ngeometry and the Polyakov loops, respectively. Furthermore, we analyze the\nspectral statistics on all three scales, comparing to predictions from random\nmatrix theory.",
        "positive": "Static potentials and glueball masses from QCD simulations with Wilson\n  sea quarks: We calculate glueball and torelon masses as well as the lowest lying hybrid\npotential in addition to the static ground state potential in lattice\nsimulations of QCD with two flavours of dynamical Wilson fermions. The results\nare obtained on lattices with $16^3\\times 32$ and $24^3\\times 40$ sites at\n$\\beta=5.6$, corresponding to a lattice spacing, $a^{-1}=2.65^{+5}_{-8}$ GeV,\nas determined from the Sommer force radius, at physical sea quark mass. The\nrange spanned in the present study of five different quark masses is reflected\nin the ratios, $0.83\\geq m_{\\pi}/m_{\\rho}\\geq 0.57$."
    },
    {
        "anchor": "Evaluation of $SU(3)$ smearing on FPGA accelerator cards: Recent FPGA accelerator cards promise large acceleration factors for some\nspecific computational tasks. In the context of Lattice QCD calculations, we\ninvestigate the possible gain of moving the $SU(3)$ gauge field smearing\nroutine to such accelerators. We study Xilinx Alveo U280 cards and use the\nassociated Vitis high-level synthesis framework. We discuss the possible pros\nand cons of such a solution based on the gathered benchmarks.",
        "positive": "Utilising optimised operators and distillation to extract scattering\n  phase shifts: In this investigation, we examine how the precision of energy spectra and\nscattering phase shifts, extracted in lattice QCD, depend upon the degree of\ndistillation type smearing. We use the variational method to extract energy\nspectra for the isospin-1, $J^{PC}=1^{--}$ channel and use the L\\\"{u}scher\nmethod to compute scattering amplitudes, relevant for the $\\rho$ resonance, in\n$\\pi\\pi$ elastic scattering. Optimised interpolating operators for a single\nground state pion are constructed and these are used to construct two pion\noperators. Calculations are performed on an anisotropic lattice with a pion\nmass of $m_\\pi=236$ MeV. We provide a comprehensive comparison of energy\nspectra and scattering phase shifts across distillation spaces of varying rank."
    },
    {
        "anchor": "Effective actions for finite temperature Lattice Gauge Theories: We consider a lattice gauge theory at finite temperature in ($d$+1)\ndimensions with the Wilson action and different couplings $\\beta_t$ and\n$\\beta_s$ for timelike and spacelike plaquettes. By using the character\nexpansion and Schwinger-Dyson type equations we construct, order by order in\n$\\beta_s$, an effective action for the Polyakov loops which is exact to all\norders in $\\beta_t$. As an example we construct the first non-trivial order in\n$\\beta_s$ for the (3+1) dimensional SU(2) model and use this effective action\nto extract the deconfinement temperature of the model.",
        "positive": "Masses and decay constants of the light mesons in the quenched\n  approximation using the tadpole--improved SW-clover action: We present results for the masses and decay constants of the light mesons in\nquenched QCD using the standard gluon action and a tadpole--improved SW--clover\nfermionic action to reduce discretisation errors. The calculation has been\ncarried out at fixed volume and three lattice spacings corresponding to\n$\\beta=5.7$, $6.0$ and $6.2$. We make comparisons with the conventional\nSW--clover scheme. We use our results to extract continuum limits and to\nquantify the size of discretisation errors at smaller $\\beta$-values."
    },
    {
        "anchor": "Equation of state and Goldstone-mode effects of the three-dimensional\n  O(2) model: We investigate numerically the three-dimensional O(2) model on 8^3-160^3\nlattices as a function of the magnetic field H. In the low-temperature phase we\nverify the H-dependence of the magnetization M induced by Goldstone modes and\ndetermine M in the thermodynamic limit both by extrapolation and by chiral\nperturbation theory. This enables us to calculate the corresponding critical\namplitude. At T_c the critical scaling behaviour of the magnetization as a\nfunction of H is used to determine another critical amplitude. In both cases we\nfind negative corrections-to-scaling. Our low-temperature results are well\ndescribed by the perturbative form of the model's magnetic equation of state,\nwith coefficients determined nonperturbatively from our data. The O(2) scaling\nfunction for the magnetization is found to have a smaller slope than the one\nfor the O(4) model.",
        "positive": "Continuum Extrapolation of Moments of Nucleon Quark Distributions in\n  Full QCD: Moments of light cone quark density, helicity, and transversity distributions\nare calculated in unquenched lattice QCD at $\\beta = 5.5$ and $\\beta = 5.3$\nusing Wilson fermions on $ 16^3 \\times 32 $ lattices. These results are\ncombined with earlier calculations at $\\beta = 5.6$ using SESAM configurations\nto study the continuum limit."
    },
    {
        "anchor": "Localization properties of Dirac modes at the Roberge-Weiss phase\n  transition: We study the localization properties of the low-lying Dirac eigenmodes in QCD\nat imaginary chemical potential $\\hat{\\mu}_I=\\pi$ at temperatures above the\nRoberge-Weiss transition temperature $T_{\\rm RW}$. We find that modes are\nlocalized up to a temperature-dependent \"mobility edge\" and delocalized above\nit, and that the mobility edge extrapolates to zero at a temperature compatible\nwith $T_{\\rm RW}$. This supports the existence of a strong connection between\nlocalization of the low Dirac modes and deconfinement, studied here for the\nfirst time in a model with a genuine deconfinement transition in the continuum\nlimit in the presence of dynamical fermions.",
        "positive": "ChPT loops for the lattice: pion mass and decay constant, HVP at finite\n  volume and $n\\bar n$-oscillations: I present higher loop order results for several calculations in Chiral\nperturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum\npolarization. 2) A three-loop calculation of the pion mass and decay constant\nin two-flavour ChPT. For the pion mass all needed auxiliary parameters can be\ndetermined from lattice calculations of $\\pi\\pi$-scattering. 3) Chiral\ncorrections to neutron-anti-neutron oscillations."
    },
    {
        "anchor": "Gauge invariant generalization of the 2D chiral Gross-Neveu model: By means of the Lee-Shrock transformation we generalize the 2D Gross-Neveu\n(GN$_2$) model to a U(1) gauge theory with charged fermion and scalar fields in\n2D ($\\chi U \\phi_2$ model). The $\\chi U \\phi_2$ model is equivalent to the\nGN$_2$ model at infinite gauge coupling. We show that the dynamical fermion\nmass generation and asymptotic freedom in the effective four-fermion coupling\npersist also when the gauge coupling decreases. These phenomena are not\ninfluenced by the XY$_2$ model phase transition at weak coupling. This suggests\nthat the $\\chi U \\phi_2$ model is in the same universality class as the GN$_2$\nmodel and thus renormalizable.",
        "positive": "Exploration of the phase structure of $SU(N_c)$ lattice gauge theory\n  with many Wilson fermions at strong coupling: We explore aspects of the phase structure of SU(2) and SU(3) lattice gauge\ntheories at strong coupling with many flavours $N_f$ of Wilson fermions in the\nfundamental representation, including the relevance to recent searches for a\nconformal window. The pseudoscalar meson mass, the quark mass and other\nquantities are observed as functions of the hopping parameter, and we find\ndeviations from the expected analytic dependence, at least for sufficiently\nlarge $N_f$. Implications of these effects for the phase structure and for the\nexistence of a (first order) bulk phase and the Aoki phase are discussed in the\ncase of $N_f/N_c \\gg 1$."
    },
    {
        "anchor": "Neural multigrid for gauge theories and other disordered systems: We present evidence that multigrid works for wave equations in disordered\nsystems, e.g. in the presence of gauge fields, no matter how strong the\ndisorder, but one needs to introduce a \"neural computations\" point of view into\nlarge scale simulations: First, the system must learn how to do the simulations\nefficiently, then do the simulation (fast).\n  The method can also be used to provide smooth interpolation kernels which are\nneeded in multigrid Monte Carlo updates.",
        "positive": "Non-Standard Physics in Leptonic and Semileptonic Decays of Charmed\n  Mesons: Recent measurements of the branching fraction for D_s -> l nu disagree with\nthe Standard Model expectation, which relies on calculations of $f_{D_s}$ from\nlattice QCD. This paper uses recent preliminary measurements from CLEO and a\nnew preliminary lattice-QCD result from this conference to update the\nsignificance of the discrepancy. The \"f_{D_s} puzzle\" stands now at 3.5sigma,\nwith sigma predominantly from the statistical uncertainty of the experiments.\nNew physics scenarios that could solve the puzzle would also lead to\nnon-Standard amplitudes mediating the semileptonic decays D -> K l nu. This\npaper shows where the new amplitudes enter the differential rate and outlines\nwhere lattice QCD calculations are needed to confront recent and forthcoming\nmeasurements."
    },
    {
        "anchor": "Multibondic Cluster Algorithm for Monte Carlo Simulations of First-Order\n  Phase Transitions: Inspired by the multicanonical approach to simulations of first-order phase\ntransitions we propose for $q$-state Potts models a combination of cluster\nupdates with reweighting of the bond configurations in the\nFortuin-Kastelein-Swendsen-Wang representation of this model. Numerical tests\nfor the two-dimensional models with $q=7, 10$ and $20$ show that the\nautocorrelation times of this algorithm grow with the system size $V$ as $\\tau\n\\propto V^\\alpha$, where the exponent takes the optimal random walk value of\n$\\alpha \\approx 1$.",
        "positive": "Heavy light decay constants on the lattice: We present results for the leptonic decays of heavy-light mesons in the\nquenched approximation and a preliminary result for f_Ds with dynamical\nfermions for Nf=2. We examine the systematic effects of extrapolating the decay\nconstants from the charm to the bottom quark mass, and find this extrapolation\nto be under control. We present a preliminary result for f_Ds{Nf=2} and compare\nto f_Ds{Nf=0} matched to have the same lattice spacing set by the Sommer scale,\nr0. We find no significant difference."
    },
    {
        "anchor": "Delta-rho in an SU(2) X U(1) chiral Yukawa model: We report on a simulation in progress of an SU(2) X U(1) fermion-Higgs model\nwith two *non-degenerate* fermion doublets. The Zaragoza proposal for chiral\nlattice fermions is used; naive fermions are studied for comparison. The aims\nof this simulation are a non-perturbative study of the decoupling of species\ndoublers, of triviality bounds on the Higgs and fermion masses and of the\nphenomenological quantity Delta-rho.",
        "positive": "Universality in the Critical Behavior of the Correlation Functions in 2d\n  Simplicial Gravity: The analogue of the loop-loop correlation function in 2d gravity for the\nplanar connected $\\phi^3$ diagrams is calculated. It is shown that although the\ndiscretized formulas are different the scaling limit is the same as for the\nloop-loop correlation function. The derivation may serve as an alternative\ndefinition of the volume-volume correlator of Euclidean quantum gravity in\n$2d$."
    },
    {
        "anchor": "Tensor Renormalization Group for fermions: We review the basic ideas of the Tensor Renormalization Group method and show\nhow they can be applied for lattice field theory models involving relativistic\nfermions and Grassmann variables in arbitrary dimensions. We discuss recent\nprogress for entanglement filtering, loop optimization, bond-weighting\ntechniques and matrix product decompositions for Grassmann tensor networks. The\nnew methods are tested with two-dimensional Wilson--Majorana fermions and\nmulti-flavor Gross--Neveu models. We show that the methods can also be applied\nto the fermionic Hubbard model in 1+1 and 2+1 dimensions.",
        "positive": "Lattice QCD spectroscopy for hadronic CP violation: The interpretation of nuclear electric dipole moment (EDM) experiments is\nclouded by large theoretical uncertainties associated with nonperturbative\nmatrix elements. In various beyond-the-Standard Model scenarios nuclear and\ndiamagnetic atomic EDMs are expected to be dominated by CP-violating\npion-nucleon interactions that arise from quark chromo-electric dipole moments.\nThe corresponding CP-violating pion-nucleon coupling strengths are, however,\npoorly known. In this work we propose a strategy to calculate these couplings\nby using spectroscopic lattice QCD techniques. Instead of directly calculating\nthe pion-nucleon coupling constants, a challenging task, we use chiral symmetry\nrelations that link the pion-nucleon couplings to nucleon sigma terms and mass\nsplittings that are significantly easier to calculate. In this work, we show\nthat these relations are reliable up to next-to-next-to-leading order in the\nchiral expansion in both SU(2) and SU(3) chiral perturbation theory. We\nconclude with a brief discussion about practical details regarding the required\nlattice QCD calculations and the phenomenological impact of an improved\nunderstanding of CP-violating matrix elements."
    },
    {
        "anchor": "Theoretical issues with staggered fermion simulations: The legality of the \"rooting trick\" in dynamical staggered fermion\nsimulations is discussed, i.e. whether the theory with the Boltzmann weight\n$\\det^{1/4}(D_\\mathrm{st})$ yields the right continuum limit. Since the problem\nis unsolved, pieces of evidence in favor and against are collected and\nexamined.",
        "positive": "Monte Carlo Study of Topological Defects in the 3D Heisenberg Model: We use single-cluster Monte Carlo simulations to study the role of\ntopological defects in the three-dimensional classical Heisenberg model on\nsimple cubic lattices of size up to $80^3$. By applying reweighting techniques\nto time series generated in the vicinity of the approximate infinite volume\ntransition point $K_c$, we obtain clear evidence that the temperature\nderivative of the average defect density $d\\langle n \\rangle/dT$ behaves\nqualitatively like the specific heat, i.e., both observables are finite in the\ninfinite volume limit. This is in contrast to results by Lau and Dasgupta [{\\em\nPhys. Rev.\\/} {\\bf B39} (1989) 7212] who extrapolated a divergent behavior of\n$d\\langle n \\rangle/dT$ at $K_c$ from simulations on lattices of size up to\n$16^3$. We obtain weak evidence that $d\\langle n \\rangle/dT$ scales with the\nsame critical exponent as the specific heat.As a byproduct of our simulations,\nwe obtain a very accurate estimate for the ratio $\\alpha/\\nu$ of the\nspecific-heat exponent with the correlation-length exponent from a finite-size\nscaling analysis of the energy."
    },
    {
        "anchor": "The $U_A(1)$ Problem on the Lattice: If the expression of the topological charge density operator, suggested by\nfermions obeying the Ginsparg--Wilson relation, is employed, it is possible to\nprove on the lattice the validity of the Witten--Veneziano formula for the\n$\\eta'$ mass. Recent numerical results from simulations with overlap fermions\nin 2 (abelian Schwinger model) and 4 (QCD) dimensions give values for the mass\nof the lightest pseudo-scalar flavour-singlet state that agree with theoretical\nexpectations and/or experimental data.",
        "positive": "Unquenched Gluon Propagator in Landau Gauge: Using lattice quantum chromodynamics (QCD) we perform an unquenched\ncalculation of the gluon propagator in Landau gauge. We use configurations\ngenerated with the AsqTad quark action by the MILC collaboration for the\ndynamical quarks and compare the gluon propagator of quenched QCD (i.e., the\npure Yang-Mills gluon propagator) with that of 2+1 flavor QCD. The effects of\nthe dynamical quarks are clearly visible and lead to a significant reduction of\nthe nonperturbative infrared enhancement relative to the quenched case."
    },
    {
        "anchor": "Baryonic Matter Onset in Two-Color QCD with Heavy Quarks: We study the cold and dense regime in the phase diagram of two-color QCD with\nheavy quarks within a three-dimensional effective theory for Polyakov loops.\nThis theory is derived from two-color QCD in a combined strong-coupling and\nhopping expansion. In particular, we study the onset of diquark density as the\nfinite-density transition of the bosonic baryons in the two-color world. In\ncontrast to previous studies of heavy dense QCD, our zero-temperature\nextrapolations are consistent with a continuous transition without binding\nenergy. They thus provide evidence that the effective theory for heavy quarks\nis capable of describing the characteristic differences between diquark\ncondensation in two-color QCD and the liquid-gas transition of nuclear matter\nin QCD.",
        "positive": "Evidence for diquarks in lattice QCD: Diquarks may play an important role in hadron spectroscopy, baryon decays and\ncolor superconductivity. We investigate the existence of diquark correlations\nin lattice QCD by considering systematically all the lowest energy diquark\nchannels in a color gauge-invariant setup. We measure mass differences between\nthe various channels and show that the positive parity scalar diquark is the\nlightest. Quark-quark correlations inside the diquark are clearly seen in this\nchannel, and yield a diquark size of order 1 fm."
    },
    {
        "anchor": "Infrared Gluon and Ghost Propagator Exponents From Lattice QCD: The compatibility of the pure power law infrared solution of QCD and lattice\ndata for the gluon and ghost propagators in Landau gauge is discussed. For the\ngluon propagator, the lattice data is well described by a pure power law with\nan infrared exponent $\\kappa \\sim 0.53$, in the Dyson-Schwinger notation.\n$\\kappa$ is measured using a technique that suppresses finite volume effects.\nThis value implies a vanishing zero momentum gluon propagator, in agreement\nwith the Gribov-Zwanziger confinement scenario. For the ghost propagator, the\nlattice data seem not to follow a pure power law, at least for the range of\nmomenta accessed in our simulation.",
        "positive": "Symmetry and Symmetry Restoration of Lattice Chiral Fermion in the\n  Overlap Formalism: Three aspects of symmetry structure of lattice chiral fermion in the overlap\nformalism are discussed. By the weak coupling expansion of the overlap Dirac\noperator, the axial anomaly associated to the chiral transformation proposed by\nLuescher is evaluated and is shown to have the correct form of the topological\ncharge density for perturbative backgrounds. Next we discuss the exponential\nsuppression of the self-energy correction of the lightest mode in the\ndomain-wall fermion/truncated overlap. Finally, we consider a supersymmetric\nextension of the overlap formula in the case of the chiral multiplet and\nexamine the symmetry structure of the action."
    },
    {
        "anchor": "Kaon and D meson semileptonic form factors from lattice QCD: We present the status of on-going calculations of the $K\\to\\pi l\\nu$ and\n$D\\to K(\\pi) l\\nu$ semileptonic form factors at $q^2=0$. These form factors are\nimportant for the determination of the CKM matrix elements\n$\\lvert{V_{us}}\\rvert$ and $\\lvert{V_{cs(d)}}\\rvert$ respectively. This work\nuses the HISQ action for both valence quarks and sea quarks on MILC $N_f=2+1+1$\nconfigurations. We employ twisted boundary conditions to calculate the form\nfactors at zero momentum transfer directly. The $K\\to\\pi$ results are an update\nto previously published results with new data at the physical point. The $D\\to\nK(\\pi)$ results are preliminary.",
        "positive": "Topology and strong four fermion interactions in four dimensions: We study massless fermions interacting through a particular four fermion term\nin four dimensions. Exact symmetries prevent the generation of bilinear fermion\nmass terms. We determine the structure of the low energy effective action for\nthe auxiliary field needed to generate the four fermion term and find it has an\nnovel structure that admits topologically non-trivial defects with non-zero\nHopf invariant. We show that fermions propagating in such a background pick up\na mass without breaking symmetries. Furthermore pairs of such defects\nexperience a logarithmic interaction. We argue that a phase transition\nseparates a phase where these defects proliferate from a broken phase where\nthey are bound tightly. We conjecture that by tuning one additional operator\nthe broken phase can be eliminated with a single BKT-like phase transition\nseparating the massless from massive phases."
    },
    {
        "anchor": "Exact Local Bosonic Algorithm for Dynamical Quarks: We present an exact local bosonic algorithm for the simulation of dynamical\nfermions in lattice QCD. We show that this algorithm is a viable alternative to\nthe Hybrid Monte Carlo algorithm.",
        "positive": "Why is the mission impossible? -- Decoupling the mirror Ginsparg-Wilson\n  fermions in the lattice models for two-dimensional abelian chiral gauge\n  theories: In the mirror fermion approach with Ginsparg-Wilson fermions, it has been\nargued that the mirror fermions do not decouple: in the 345 model with Dirac-\nand Majorana-Yukawa couplings to XY-spin field, the two-point vertex function\nof the (external) gauge field in the mirror sector shows a singular non-local\nbehavior in the PMS phase. We re-examine why the attempt seems a \"Mission:\nImpossible\" in the 345 model. We point out that the effective operators to\nbreak the fermion number symmetries ('t Hooft operators plus others) in the\nmirror sector do not have sufficiently strong couplings even in the limit of\nlarge Majorana-Yukawa couplings. We observe also that the type of Majorana mass\nterm considered there is singular in the large limit due to the nature of the\nchiral projection of the Ginsparg-Wilson fermions, but a slight modification\nwithout such singularity is allowed by virtue of the very nature. We then\nconsider a simpler four-flavor axial gauge model, the 1$^4$(-1)$^4$ model, in\nwhich the U(1)$_A$ gauge and Spin(6)(SU(4)) global symmetries prohibit the\nbilinear terms, but allow the quartic terms to break all the other continuous\nmirror-fermion symmetries. In the strong-coupling limit of the quartic\noperators, the model is well-behaved and simplified. Through Monte-Carlo\nsimulations in the weak gauge coupling limit, we show a numerical evidence that\nthe two-point vertex function of the gauge field in the mirror sector shows a\nregular local behavior, and we still argue that all you need is killing the\ncontinuous mirror-fermion symmetries with would-be gauge anomalies non-matched.\nFinally, by gauging a U(1) subgroup of the U(1)$_A$$\\times$ Spin(6)(SU(4)) of\nthe previous model, we formulate the $2 1 (-1)^3$ chiral gauge model and argue\nthat the induced fermion measure term satisfies the required locality property\nand provides a solution to the reconstruction theorem."
    },
    {
        "anchor": "Baryon electric charge correlation as a magnetometer of QCD: The correlation between net baryon number and electric charge,\n$\\chi_{11}^{\\rm BQ}$, can serve as a magnetometer of QCD. This is demonstrated\nby lattice QCD computations using the highly improved staggered quarks with\nphysical pion mass of $M_\\pi=135~$MeV on $N_\\tau=8$ and 12 lattices. We find\nthat $\\chi_{11}^{\\rm BQ}$ along the transition line starts to increase rapidly\nwith magnetic field strength $eB\\gtrsim 2M_\\pi^2$ and by a factor 2 at\n$eB\\simeq 8M_\\pi^2$. Furthermore, the ratio of electric charge chemical\npotential to baryon chemical potential, $\\mu_{\\rm Q}/\\mu_{\\rm B}$, shows\nsignificant dependence on the magnetic field strength and varies from the ratio\nof electric charge to baryon number in the colliding nuclei in heavy ion\ncollisions. These results can provide baselines for effective theory and model\nstudies, and both $\\chi_{11}^{\\rm BQ}$ and $\\mu_{\\rm Q}/\\mu_{\\rm B}$ could be\nuseful probes for the detection of magnetic fields in relativistic heavy ion\ncollision experiments as compared with corresponding results from the hadron\nresonance gas model.",
        "positive": "$\\bar{b}\\bar{b}ud$ tetraquark resonances in the Born-Oppenheimer\n  approximation using lattice QCD potentials: We study tetraquark resonances using lattice QCD potentials for a pair of\nstatic antiquarks $\\bar{b}\\bar{b}$ in the presence of two light quarks $ud$.\nThe system is treated in the Born-Oppenheimer approximation and we use the\nemergent wave method. We focus on the isospin $I=0$ channel, but consider\ndifferent orbital angular momenta $l$ of the heavy antiquarks $\\bar{b}\\bar{b}$.\nWe extract the phase shifts and search for $\\mbox{S}$ and $\\mbox{T}$ matrix\npoles on the second Riemann sheet. For orbital angular momentum $l=1$ we find a\ntetraquark resonance with quantum numbers $I(J^P)=0(1^-)$, resonance mass\n$m=10576^{+4}_{-4} \\, \\textrm{MeV}$ and decay width $\\Gamma= 112^{+90}_{-103}\n\\textrm{MeV}$, which can decay into two $B$ mesons."
    },
    {
        "anchor": "Tuning Actions and Observables in Lattice QCD: We propose a strategy for conducting lattice QCD simulations at fixed volume\nbut variable quark mass so as to investigate the physical effects of dynamical\nfermions. We present details of techniques which enable this to be carried out\neffectively, namely the tuning in bare parameter space and efficient stochastic\nestimation of the fermion determinant. Preliminary results and tests of the\nmethod are presented. We discuss further possible applications of these\ntechniques.",
        "positive": "Method for Extracting the Glueball Wave Function: We describe a nonperturbative method for calculating the QCD vacuum and\nglueball wave functions, based on an eigenvalue equation approach to\nHamiltonian lattice gauge theory. Therefore, one can obtain more physical\ninformation than the conventional simulation methods. For simplicity, we take\nthe 2+1 dimensional U(1) model as an example. The generalization of this method\nto 3+1 dimensional QCD is straightforward."
    },
    {
        "anchor": "Approximated seventh order calculation of vacuum wave function of 2+1\n  dimensional SU(2) lattice gauge theory: Using the coupled cluster expansion with the random phase approximation, we\ncalculate the long wavelength vacuum wave function and the vacuum energy of 2+1\ndimensional Hamiltonian SU(2) lattice gauge theory (LGT) up to the seventh\norder. The coefficients $\\mu_0$, $\\mu_2$ of the vacuum wave function show good\nscaling behavior and convergence in high order calculations.",
        "positive": "Complex Probability Distributions: A Solution for the Long-Standing\n  Problem of QCD at Finite Density: We show how the prescription of taking the absolute value of the fermion\ndeterminant in the integration measure of QCD at finite density, forgetting its\nphase, reproduces the correct thermodynamical limit. This prescription, which\napplies also to other gauge theories with non-positive-definite integration\nmeasure, also has the advantage of killing finite size effects due to extremely\nsmall mean values of the cosine of the phase of the fermion determinant. We\nalso give an explanation for the pathological behaviour of quenched QCD at\nfinite density."
    },
    {
        "anchor": "A Precise Determination of the Running Coupling in the SU(3) Yang-Mills\n  Theory: A non-perturbative finite-size scaling technique is used to study the\nevolution of the running coupling (in a certain adapted scheme) in the SU(3)\nYang-Mills theory. At low energies contact is made with the fundamental\ndynamical scales, such as the string tension K, while at larger energies the\ncoupling is shown to evolve according to perturbation theory. In that regime\nthe coupling in the MS-bar scheme of dimensional regularization is obtained\nwith an estimated total error of a few percent.",
        "positive": "Transverse momentum distributions inside the nucleon from lattice QCD: This work applies lattice QCD to compute quark momentum distributions in the\nnucleon. We explore a novel approach based on non-local operators in order to\nanalyze transverse momentum dependent parton distribution functions, which\nencode information about the intrinsic motion of quarks inside the nucleon. Our\ncalculations are based on MILC gauge configurations and domain wall fermion\npropagators from LHPC. One interesting observation is that the transverse\nmomentum dependent density of polarized quarks in a polarized nucleon is\nvisibly deformed. Moreover, we can test the assumption that longitudinal and\ntransverse momentum dependence factorize within a certain kinematical region. A\nmore elaborate operator geometry is required to enable a quantitative\ncomparison to azimuthal asymmetries observable in experiments such as\nsemi-inclusive deeply inelastic scattering, and to study time-reversal odd\ndistributions such as the Sivers function. First steps in this direction are\nencouraging."
    },
    {
        "anchor": "Remarks on the pion-nucleon sigma-term: The pion-nucleon $\\sigma$-term can be stringently constrained by the\ncombination of analyticity, unitarity, and crossing symmetry with\nphenomenological information on the pion-nucleon scattering lengths. Recently,\nlattice calculations at the physical point have been reported that find lower\nvalues by about $3\\sigma$ with respect to the phenomenological determination.\nWe point out that a lattice measurement of the pion-nucleon scattering lengths\ncould help resolve the situation by testing the values extracted from\nspectroscopy measurements in pionic atoms.",
        "positive": "Multiple molecular dynamics time-scales in Hybrid Monte Carlo fermion\n  simulations: A scheme for separating the high- and low-frequency molecular dynamics modes\nin Hybrid Monte Carlo (HMC) simulations of gauge theories with dynamical\nfermions is presented. The algorithm is tested in the Schwinger model with\nWilson fermions."
    },
    {
        "anchor": "Exact renormalization-group analysis of first order phase transitions in\n  clock models: We analyze the exact behavior of the renormalization group flow in\none-dimensional clock-models which undergo first order phase transitions by the\npresence of complex interactions. The flow, defined by decimation, is shown to\nbe single-valued and continuous throughout its domain of definition, which\ncontains the transition points. This fact is in disagreement with a recently\nproposed scenario for first order phase transitions claiming the existence of\ndiscontinuities of the renormalization group. The results are in partial\nagreement with the standard scenario. However in the vicinity of some fixed\npoints of the critical surface the renormalized measure does not correspond to\na renormalized Hamiltonian for some choices of renormalization blocks. These\npathologies although similar to Griffiths-Pearce pathologies have a different\nphysical origin: the complex character of the interactions. We elucidate the\ndynamical reason for such a pathological behavior: entire regions of coupling\nconstants blow up under the renormalization group transformation. The flows\nprovide non-perturbative patterns for the renormalization group behavior of\nelectric conductivities in the quantum Hall effect.",
        "positive": "Force Gradient Integrators: We present initial results of the use of Force Gradient integrators for\nlattice field theories. These promise to give significant performance\nimprovements, especially for light fermions and large lattices. Our results\nshow that this is indeed the case, indicating a speed-up of more than a factor\nof two, which is expected to increase as the integration step size becomes\nsmaller for larger lattices and smaller fermion masses."
    },
    {
        "anchor": "Advances in lattice hadron physics calculations using the gradient flow: Lattice calculations of hadronic observables are aggravated by short-distance\nfluctuations. The gradient flow, which can be viewed as a particular\nrealisation of the coarse-graining step of momentum space RG transformations,\nproves a powerful tool for evolving the lattice gauge field to successively\nlonger length scales for any initial coupling. Already at small flow times we\nfind the signal-to-noise ratio of two- and three-point functions significantly\nenhanced and the projection onto the ground state largely improved, while the\neffect on the hadronic observables considered here to be negligible. A further\nbenefit is that far fewer conjugate gradient iterations are needed for the\nWilson-Dirac inverter to converge. Additionally, we find the renormalisation\nconstants of quark bilinears to be significantly closer to unity.",
        "positive": "QCD Thermodynamics on the Lattice from the Gradient Flow: To obtain the precise values of the bulk quantities and transport\ncoefficients in quark-gluon-plasma phase, we propose that a direct calculation\nof the renormalized energy-momentum tensor (EMT) on the lattice using the\ngradient flow. From one-point function of EMT, authors in Ref.[1] obtained the\ninteraction measure and thermal entropy. The results are consistent with the\none obtained by the integral method. Based on the success, we try to measure\nthe two-point function of EMT, which is related to the transport coefficients.\nAdvantages of our method are (1) a clear signal because of the smearing effects\nof the gradient flow and (2) no need to calculate the wave function\nrenormalization of EMT. In addition, we give a short remark on a comparison of\nthe numerical cost between the positive- and adjoint-flow methods for fermions,\nneeded to obtain the EMT in the (2+1) flavor QCD."
    },
    {
        "anchor": "Greens function of a free massive scalar field on the lattice: We propose a method to calculate the Greens function of a free massive scalar\nfield on the lattice numerically to very high precision. For masses m < 2 (in\nlattice units) the massive Greens function can be expressed recursively in\nterms of the massless Greens function and just two additional mass-independent\nconstants.",
        "positive": "A tmQCD mixed-action approach to flavour physics: We discuss a mixed-action approach in which sea quarks are regularised using\nnon-perturbatively ${\\rm O}(a)$ improved Wilson fermions, while a fully-twisted\ntmQCD action is used for valence quarks. In this setup, automatic ${\\rm O}(a)$\nimprovement is preserved for valence observables, apart from small residual\n${\\rm O}(a)$ effects from the sea. A strategy for matching sea and valence is\nset up, and carried out for $N_\\mathrm{f}=2+1$ CLS ensembles with open boundary\nconditions at several simulation points. The scaling of basic light-quark\nobservables such as the pseudoscalar meson decay constant is studied, as well\nas the isospin splitting of pseudoscalar meson masses."
    },
    {
        "anchor": "General Algorithm For Improved Lattice Actions on Parallel Computing\n  Architectures: Quantum field theories underlie all of our understanding of the fundamental\nforces of nature. The are relatively few first principles approaches to the\nstudy of quantum field theories [such as quantum chromodynamics (QCD) relevant\nto the strong interaction] away from the perturbative (i.e., weak-coupling)\nregime. Currently the most common method is the use of Monte Carlo methods on a\nhypercubic space-time lattice. These methods consume enormous computing power\nfor large lattices and it is essential that increasingly efficient algorithms\nbe developed to perform standard tasks in these lattice calculations. Here we\npresent a general algorithm for QCD that allows one to put any planar improved\ngluonic lattice action onto a parallel computing architecture. High performance\nmasks for specific actions (including non-planar actions) are also presented.\nThese algorithms have been successfully employed by us in a variety of lattice\nQCD calculations using improved lattice actions on a 128 node Thinking Machines\nCM-5.\n  {\\underline{Keywords}}: quantum field theory; quantum chromodynamics;\nimproved actions; parallel computing algorithms.",
        "positive": "Lattice investigation of an inhomogeneous phase of the 2+1-dimensional\n  Gross-Neveu model in the limit of infinitely many flavors: We investigate the phase structure of the 2+1-dimensional Gross-Neveu model\nin the large-Nf limit, where Nf denotes the number of fermion flavors. We\ndiscuss two different fermion representations and their implication on the\ninterpretation of a discrete symmetry of the action. We present numerical\nresults, which indicate the existence of an inhomogeneous phase similar as in\nthe 1+1-dimensional Gross-Neveu model."
    },
    {
        "anchor": "Sp(4) gauge theories on the lattice: Quenched fundamental and\n  antisymmetric fermions: We perform lattice studies of meson mass spectra and decay constants of the\n$Sp(4)$ gauge theory in the quenched approximation. We consider two species of\n(Dirac) fermions as matter field content, transforming in the 2-index\nantisymmetric and the fundamental representation of the gauge group,\nrespectively. All matter fields are formulated as Wilson fermions. We\nextrapolate to the continuum and massless limits, and compare to each other the\nresults obtained for the two species of mesons. In the case of two fundamental\nand three antisymmetric fermions, the long-distance dynamics is relevant for\ncomposite Higgs models. This is the first lattice study of this class of\ntheories. The global $SU(4) \\times SU(6)$ symmetry is broken to the $Sp(4)\n\\times SO(6)$ subgroup, and the condensates align with the explicit mass terms\npresent in the lattice formulation of the theory. The main results of our\nquenched calculations are that, with fermions in the 2-index antisymmetric\nrepresentation of the group, the masses squared and decay constant squared of\nall the mesons we considered are larger than the corresponding quantities for\nthe fundamental representation, by factors that vary between $\\sim$1.2 and\n$\\sim$2.7. We also present technical results that will be useful for future\nlattice investigations of dynamical simulations, of composite chimera baryons,\nand of the approach to large $N$ in the $Sp(2N)$ theories considered. We\nbriefly discuss their high-temperature behaviour, where symmetry restoration\nand enhancement are expected.",
        "positive": "Implementation of the twisted mass fermion operator in the QUDA library: We discuss an extension of the QUDA library for the Wilson twisted mass\noperator. A performance analysis is presented for both degenerate and\nnon-degenerate flavor doublets. The degenerate twisted mass fermion operator\nruns at up to 190, 487 and 856 Gflops, for double, single and half precisions\nrespectively on recent NVIDIA Kepler GPUs, while our implementation for the\nnon-degenerate flavor doublet allows to reach 163, 516 and 879 GFlops,\nrespectively. The code is currently in production for the hadron structure\nstudy."
    },
    {
        "anchor": "Determination of latent heat at the finite temperature phase transition\n  of SU(3) gauge theory: We calculate the energy gap (latent heat) and pressure gap between the hot\nand cold phases of the SU(3) gauge theory at the first order deconfining phase\ntransition point. We perform simulations around the phase transition point with\nthe lattice size in the temporal direction $N_t=6,$ 8 and 12 and extrapolate\nthe results to the continuum limit. The energy density and pressure are\nevaluated by the derivative method with nonperturabative anisotropy\ncoefficients. We find that the pressure gap vanishes at all values of $N_t$.\nThe spatial volume dependence in the latent heat is found to be small on large\nlattices. Performing extrapolation to the continuum limit, we obtain $\\Delta\n\\epsilon/T^4 = 0.75 \\pm 0.17$ and $\\Delta (\\epsilon -3 p)/T^4 = 0.623 \\pm\n0.056.$ We also tested a method using the Yang-Mills gradient flow. The\npreliminary results are consistent with those by the derivative method within\nthe error.",
        "positive": "Behavior near $\u03b8=\u03c0$ of the mass gap in the 2D O(3) non-linear\n  sigma model: The validity of the Haldane's conjecture entails that the mass gap of the\n2-dimensional O(3) non-linear sigma model with a $\\theta$-term must tend to\nzero as $\\theta$ approaches the value $\\pi$ by following a precise law. In the\npresent paper we extract the related critical exponents by simulating the model\nat imaginary $\\theta$."
    },
    {
        "anchor": "Phase diagram of the lattice Wess-Zumino model from rigorous lower\n  bounds on the energy: We study the lattice N=1 Wess-Zumino model in two dimensions and we construct\na sequence $\\rho^{(L)}$ of exact lower bounds on its ground state energy\ndensity $\\rho$, converging to $\\rho$ in the limit $L\\to\\infty$. The bounds\n$\\rho^{(L)}$ can be computed numerically on a finite lattice with $L$ sites and\ncan be exploited to discuss dynamical symmetry breaking. The transition point\nis determined and compared with recent results based on large-scale Green\nFunction Monte Carlo simulations with good agreement.",
        "positive": "The axial N to Delta transition form factors from Lattice QCD: We evaluate the N to Delta axial transition form factors in lattice QCD in\nthe quenched theory, with two degenerate flavors of dynamical Wilson fermions\nand using domain wall valence fermions with staggered sea quark configurations.\nWe predict the ratio $C_5^A(q^2)/C_3^V(q^2)$ relevant to the parity violating\nasymmetry and check the validity of the off-diagonal Goldberger-Treiman\nrelation."
    },
    {
        "anchor": "Charm baryons at finite temperature on anisotropic lattices: Singly, doubly and triply charmed baryons are investigated at multiple\ntemperatures using the anisotropic FASTSUM 'Generation 2L' ensembles. We\ndiscuss the temperature dependence of these baryons' spectra in both parity\nchannels with a focus on the confining phase. To further qualify the behaviour\nof these states around the pseudocritical temperature, we investigate the\neffect of chiral symmetry restoration for light quarks. We find that an\nestimate of the pseudocritical temperature can still be found from positive and\nnegative-parity charmed baryon correlators, even when parity doubling itself is\nnot very evident (as expected).",
        "positive": "Recent Developments of Muon g-2 from Lattice QCD: One of the most promising quantities for the search of signatures of physics\nbeyond the Standard Model is the anomalous magnetic moment $g-2$ of the muon,\nwhere a comparison of the experimental result with the Standard Model estimate\nyields a deviation of about $3.5~\\sigma$. On the theory side, the largest\nuncertainty arises from the hadronic sector, namely the hadronic vacuum\npolarisation and the hadronic light-by-light scattering. I review recent\nprogress in calculating the hadronic contributions to the muon $g-2$ from the\nlattice and discuss the prospects and challenges to match the precision of the\nupcoming experiments."
    },
    {
        "anchor": "Asymptotic scaling in the two-dimensional $SU(3)$ $\u03c3$-model at\n  correlation length $4 \\times 10^5$: We carry out a high-precision simulation of the two-dimensional $SU(3)$\nprincipal chiral model at correlation lengths $\\xi$ up to $\\approx\\! 4 \\times\n10^5$, using a multi-grid Monte Carlo (MGMC) algorithm. We extrapolate the\nfinite-volume Monte Carlo data to infinite volume using finite-size-scaling\ntheory, and we discuss carefully the systematic and statistical errors in this\nextrapolation. We then compare the extrapolated data to the\nrenormalization-group predictions. For $\\xi \\gtapprox 10^3$ we observe good\nasymptotic scaling in the bare coupling; at $\\xi \\approx 4 \\times 10^5$ the\nnonperturbative constant is within 2--3\\% of its predicted limiting value.",
        "positive": "Scaling of Chiral Order Parameter in Two-Flavor QCD: The finite temperature transition of QCD with two degenerate light quarks is\nstudied on the lattice with a renormalization group improved gauge action and\nthe Wilson quark action. We have made simulations on an $8^3\\times 4$ lattice\nnear the chiral transition point. It is shown that the chiral condensate which\nis the order parameter of chiral symmetry satisfies remarkably a scaling\nrelation with the exponents of the three dimensional O(4) Heisenberg model.\nThis indicates that the chiral transition in two-flavor QCD is of second order\nin the continuum limit."
    },
    {
        "anchor": "Discrete reflection groups and induced representations of Poincare group\n  on the lattice: We continue the program, presented in previous Symposia, of discretizing\nphysical models. In particular we calculate the integral Lorentz\ntransformations with the help of discrete reflection groups, and use them for\nthe covariance of Klein-Gordon and Dirac wave equation on the lattice. Finally\nwe define the unitary representation of Poincar group on discrete momentum and\nconfiguration space, induced by integral representations of its closed\nsubgroup.",
        "positive": "Heavy-light mesons with staggered light quarks: We demonstrate the viability of improved staggered light quarks in studies of\nheavy-light systems. Our method for constructing heavy-light operators exploits\nthe close relation between naive and staggered fermions. The new approach is\ntested on quenched configurations using several staggered actionsn combined\nwith nonrelativistic heavy quarks. The B_s meson kinetic mass, the hyperfine\nand 1P-1S splittings in B_s, and the decay constant f_{B_s} are calculated and\ncompared to previous quenched lattice studies. An important technical detail,\nBayesian curve-fitting, is discussed at length."
    },
    {
        "anchor": "Lattice status of gluonia/glueballs: I briefly review lattice QCD calculations that study the 0++ glueball and\ndiscuss implications for light flavour singlet 0++ mesons.",
        "positive": "Hadron-Hadron Interactions from Imaginary-time Nambu-Bethe-Salpeter Wave\n  Function on the Lattice: Imaginary-time Nambu-Bethe-Salpeter (NBS) wave function is introduced to\nextend our previous approach for hadron-hadron interactions on the lattice.\nScattering states of hadrons with different energies encoded in the NBS\nwave-function are utilized to extract non-local hadron-hadron potential. \"The\nground state saturation\", which is commonly used in lattice QCD but is hard to\nbe achieved for multi-baryons, is not required. We demonstrate that the present\nmethod works efficiently for the nucleon-nucleon interaction (the potential and\nthe phase shift) in the 1S_0 channel."
    },
    {
        "anchor": "Worldvolume approach to the tempered Lefschetz thimble method: As a solution towards the numerical sign problem, we propose a novel Hybrid\nMonte Carlo algorithm, in which molecular dynamics is performed on a continuum\nset of integration surfaces foliated by the antiholomorphic gradient flow (\"the\nworldvolume of an integration surface\"). This is an extension of the tempered\nLefschetz thimble method (TLTM), and solves the sign and multimodal problems\nsimultaneously as the original TLTM does. Furthermore, in this new algorithm,\none no longer needs to compute the Jacobian of the gradient flow in generating\na configuration, and only needs to evaluate its phase upon measurement. To\ndemonstrate that this algorithm works correctly, we apply the algorithm to a\nchiral random matrix model, for which the complex Langevin method is known not\nto work.",
        "positive": "Large N: Some mysterious features of the strong interactions become easily understood\nif our usual QCD with N=3 is `close to' SU(oo) and if the latter theory is\nconfining. N=oo theories are theoretically simpler; in particular there has\nbeen much progress in constructing weak-coupling duals in string theory. In\nthis poster I will describe some of the things that recent lattice calculations\ntell us about the large-N limit of SU(N) gauge theories in 3+1 dimensions. The\nfocus is on confinement, how close SU(oo) is to SU(3), new stable strings at\nlarger N, the Pomeron, deconfinement, topology, 't Hooft string tensions. I\nalso allude to other topics, such as the high-T pressure deficit, chiral\nphysics and the phases of the theory."
    },
    {
        "anchor": "Baryon spectrum with $N_f=2+1+1$ twisted mass fermions: The masses of the low lying baryons are evaluated using a total of ten\nensembles of dynamical twisted mass fermion gauge configurations. The\nsimulations are performed using two degenerate flavors of light quarks, and a\nstrange and a charm quark fixed to approximately their physical values. The\nlight sea quarks correspond to pseudo scalar masses in the range of about\n210~MeV to 430~MeV. We use the Iwasaki improved gluonic action at three values\nof the coupling constant corresponding to lattice spacing $a=0.094$~fm,\n0.082~fm and 0.065~fm determined from the nucleon mass. We check for both\nfinite volume and cut-off effects on the baryon masses. We examine the issue of\nisospin symmetry breaking for the octet and decuplet baryons and its dependence\non the lattice spacing. We show that in the continuum limit isospin breaking is\nconsistent with zero, as expected. We performed a chiral extrapolation of the\nforty baryon masses using SU(2) $\\chi$PT. After taking the continuum limit and\nextrapolating to the physical pion mass our results are in good agreement with\nexperiment. We provide predictions for the mass of the doubly charmed\n$\\Xi_{cc}^*$, as well as of the doubly and triply charmed $\\Omega$s that have\nnot yet been determined experimentally.",
        "positive": "Extracting the low-energy constant $L_0^r$ at three flavors from\n  pion-kaon scattering: Based on our analysis of the contributions from the connected and\ndisconnected contraction diagrams to the pion-kaon scattering amplitude, we\nprovide the first determination of the only free low-energy constant at\n$\\mathcal{O}(p^4)$, known as $L_0^r$, in SU$(4|1)$ Partially-Quenched Chiral\nPerturbation Theory using the data from the Extended Twisted Mass\nCollaboration, $L_0^r(\\mu=M_\\rho) = 0.77(20)(25)(7)(7)(2)\\cdot 10^{-3}$. The\ntheory uncertainties originate from the unphysical scattering length, the\nphysical low-energy constants, the higher-oder chiral corrections, the\n(lattice) meson masses and the pion decay constant, respectively"
    },
    {
        "anchor": "Localization properties of the topological charge density and the low\n  lying eigenmodes of overlap fermions: Overlap fermions, which preserve exact chiral symmetry on the lattice,\nprovide a powerful tool for investigating the topological structure of the\nvacuum. Applying this formulation to zero-temperature quenched SU(3)\nconfigurations generated by means of the Luescher-Weisz action, we define the\ntopological charge density with and without UV filtering and study its\nproperties by looking at the density profile and the two-point correlation\nfunction. We observe that the density possesses global sign coherent\nstructures, which get increasingly tangled as more and more modes are included.\nThis change of the structure is also detected by the increasing negative tail\nof the two-point function. We also study the inverse participation ratio of the\neigenmodes and discuss their dimensionality.",
        "positive": "On the absence of chiral fermions in interacting lattice theories: We consider interacting theories with a compact internal symmetry group on a\nregular lattice. We show that the spectrum is necessarily vector-like provided\nthe following conditions are satisfied: (a)~weak form of locality,\n(b)~relativistic continuum limit without massless bosons, and (c)~pole-free\neffective vertex functions for conserved currents.\n  The proof exploits the zero frequency inverse retarded propagator of an\nappropriate set of interpolating fields as an effective quadratic hamiltonian,\nto which the Nielsen-Ninomiya theorem is applied.\n  The main results of this paper have been reported in WIS-93/56-JUNE-PH,\nhep-lat/9306023."
    },
    {
        "anchor": "Charm hadrons and lattice QCD: We review two lattice calculations involving charm hadrons: a determination\nof the vector and scalar form factors of the semileptonic $D \\to \\pi \\ell \\nu$\ndecays, which are relevant for the extraction of the CKM matrix element $\\lvert\nV_{cd} \\rvert$ from experimental data, and a calculation of the matrix elements\nof four-fermion operators relevant to the description of the neutral D mixing\nin the Standard Model and its extensions. Both analyses are based on the gauge\nconfigurations produced by the European Twisted Mass Collaboration with $N_f =\n2 + 1 + 1$ flavors of dynamical quarks. We simulated at three different values\nof the lattice spacing and with pion masses as small as 210 MeV.",
        "positive": "Update on the gradient flow scale on the 2+1+1 HISQ ensembles: We report on the ongoing effort of improving the determination of the\ngradient flow scale on the (2+1+1)-flavor HISQ ensembles generated by the MILC\ncollaboration. We compute the scales $\\sqrt{t_0}/a$ and $w_0/a$ with the Wilson\nand Symanzik flow using three discretizations for the action density: clover,\nWilson and tree-level Symanzik improved. For the absolute scale setting, we\nintend to employ the $\\Omega$-baryon mass, but are also using the pion decay\nconstant while the $\\Omega$-mass calculations are in progress."
    },
    {
        "anchor": "Two-baryon systems from HAL QCD method and the mirage in the temporal\n  correlation of the direct method: Both direct and HAL QCD methods are currently used to study the hadron\ninteractions in lattice QCD. In the direct method, the eigen-energy of\ntwo-particle is measured from the temporal correlation. Due to the\ncontamination of excited states, however, the direct method suffers from the\nfake eigen-energy problem, which we call the \"mirage problem,\" while the HAL\nQCD method can extract information from all elastic states by using the spatial\ncorrelation. In this work, we further investigate systematic uncertainties of\nthe HAL QCD method such as the quark source operator dependence, the\nconvergence of the derivative expansion of the non-local interaction kernel,\nand the single baryon saturation, which are found to be well controlled. We\nalso confirm the consistency between the HAL QCD method and the L\\\"uscher's\nfinite volume formula. Based on the HAL QCD potential, we quantitatively\nconfirm that the mirage plateau in the direct method is indeed caused by the\ncontamination of excited states.",
        "positive": "A new model for confinement: We propose a new approach towards the understanding of confinement. Starting\nfrom an anisotropic five dimensional pure gauge theory, we approach a second\norder phase transition where the system reduces dimensionally. Dimensional\nreduction is realized via localization of the gauge and scalar degrees of\nfreedom on four dimensional branes. The gauge coupling deriving from the brane\nWilson loop observable runs like an asymptotically free coupling at short\ndistance, while it exhibits clear signs of string formation at long distance.\nThe regularization used is the lattice. We take the continuum limit by keeping\nthe ratio of the lattice spacing in the brane over the lattice spacing along\nthe extra dimension constant and smaller than one."
    },
    {
        "anchor": "Finite-Temperature Phase Structure of Lattice QCD with Wilson Quark\n  Action: The long-standing issue of the nature of the critical line of lattice QCD\nwith the Wilson quark action at finite-temperatures, defined to be the line of\nvanishing pion screening mass, and its relation to the line of\nfinite-temperature chiral tansition is examined. Analytical and numerical\nevidence are presented that the critical line forms a cusp at a finite gauge\ncoupling, and the line of chiral transition runs past the tip of the cusp\nwithout touching the critical line. Implications on the continuum limit and the\nflavor dependence of chiral transition are discussed.",
        "positive": "$\u039b_c \\to N$ form factors from lattice QCD and phenomenology of\n  $\u039b_c \\to n \\ell^+ \u03bd_\\ell$ and $\u039b_c \\to p \u03bc^+ \u03bc^-$ decays: A lattice QCD determination of the $\\Lambda_c \\to N$ vector, axial vector,\nand tensor form factors is reported. The calculation was performed with $2+1$\nflavors of domain wall fermions at lattice spacings of $a\\approx 0.11\\:{\\rm\nfm},\\:0.085\\:{\\rm fm}$ and pion masses in the range $230\\:{\\rm MeV} \\lesssim\nm_\\pi \\lesssim 350$ MeV. The form factors are extrapolated to the continuum\nlimit and the physical pion mass using modified $z$ expansions. The rates of\nthe charged-current decays $\\Lambda_c \\to n\\, e^+ \\nu_e$ and $\\Lambda_c \\to n\\,\n\\mu^+ \\nu_\\mu$ are predicted to be $\\left( 0.405 \\pm 0.016_{\\,\\rm stat} \\pm\n0.020_{\\,\\rm syst} \\right)|V_{cd}|^2 \\:{\\rm ps}^{-1}$ and $\\left( 0.396 \\pm\n0.016_{\\,\\rm stat} \\pm 0.020_{\\,\\rm syst} \\right)|V_{cd}|^2 \\:{\\rm ps}^{-1}$,\nrespectively. The phenomenology of the rare charm decay $\\Lambda_c \\to p\\,\n\\mu^+ \\mu^-$ is also studied. The differential branching fraction, the fraction\nof longitudinally polarized dimuons, and the forward-backward asymmetry are\ncalculated in the Standard Model and in an illustrative new-physics scenario."
    },
    {
        "anchor": "Generalized Parton Distributions and the Spin Structure of the Nucleon: Generalized parton distributions are a new type of hadronic observables which\nhas recently stimulated great interest among theorists and experimentalists\nalike. Introduced to delineate the spin structure of the nucleon, the orbital\nangular momentum of quarks in particular, the new distributions contain vast\ninformation about the internal structure of the nucleon, with the usual\nelectromagnetic form factors and Feynman parton distributions as their special\nlimits. While new perturbative QCD processes, such as deeply virtual Compton\nscattering and exclusive meson production, have been found to measure the\ndistributions directly in experiments, lattice QCD offers a great promise to\nprovide the first-principle calculations of these interesting observables.",
        "positive": "B_K from quenched overlap QCD: We present an exploratory calculation of the standard model Delta S=2 matrix\nelement relevant for indirect CP violation in K -> pi pi decays. The\ncomputation is performed with overlap fermions in the quenched approximation at\nbeta=6.0 on a 16^3x32 lattice. The resulting bare matrix element is\nrenormalized non-perturbatively. Our preliminary result is B_K^{NDR}(2\nGeV)=0.61(7), where the error does not yet include an estimate of systematic\nuncertainties."
    },
    {
        "anchor": "Non-trivial \u03b8-Vacuum Effects in the 2-d O(3) Model: We study \\theta-vacua in the 2-d lattice O(3) model using the standard action\nand an optimized constraint action with very small cut-off effects, combined\nwith the geometric topological charge. Remarkably, dislocation lattice\nartifacts do not spoil the non-trivial continuum limit at \\theta\\ non-zero, and\nthere are different continuum theories for each value of \\theta. A very precise\nMonte Carlo study of the step scaling function indirectly confirms the exact\nS-matrix of the 2-d O(3) model at \\theta = \\pi.",
        "positive": "QCD Thermodynamics with Improved Actions: The thermodynamics of the SU(3) gauge theory has been analyzed with tree\nlevel and tadpole improved Symanzik actions. A comparison with the continuum\nextrapolated results for the standard Wilson action shows that improved actions\nlead to a drastic reduction of finite cut-off effects already on lattices with\ntemporal extent $N_\\tau=4$. Results for the pressure, the critical temperature,\nsurface tension and latent heat are presented. First results for the\nthermodynamics of four-flavour QCD with an improved staggered action are also\npresented. They indicate similarly large improvement factors for bulk\nthermodynamics."
    },
    {
        "anchor": "Path integral contour deformations for observables in $SU(N)$ gauge\n  theory: Path integral contour deformations have been shown to mitigate sign and\nsignal-to-noise problems associated with phase fluctuations in lattice field\ntheories. We define a family of contour deformations applicable to $SU(N)$\nlattice gauge theory that can reduce sign and signal-to-noise problems\nassociated with complex actions and complex observables. For observables, these\ncontours can be used to define deformed observables with identical expectation\nvalue but different variance. As a proof-of-principle, we apply machine\nlearning techniques to optimize the deformed observables associated with Wilson\nloops in two dimensional $SU(2)$ and $SU(3)$ gauge theory. We study loops\nconsisting of up to 64 plaquettes and achieve variance reduction of up to 4\norders of magnitude.",
        "positive": "Finite-Volume Scaling of the Wilson-Dirac Operator Spectrum: The microscopic spectral density of the Hermitian Wilson-Dirac operator is\ncomputed numerically in quenched lattice QCD. We demonstrate that the results\ngiven for fixed index of the Wilson-Dirac operator can be matched by the\npredictions from Wilson chiral perturbation theory. We test successfully the\nfinite volume and the mass scaling predicted by Wilson chiral perturbation\ntheory at fixed lattice spacing."
    },
    {
        "anchor": "Aspects of the Higgs phase in SU(2)xU(1) lattice gauge Higgs theory: Using a simplified lattice version of the electroweak sector of the standard\nmodel, with dynamical fermions excluded, we determine at fixed Weinberg angle\nthe transition line between the confined phase and the Higgs phase, the latter\ndefined as the region where the global center subgroup of the gauge group is\nspontaneously broken, and \"separation of charge\" confinement disappears. We\nthen search, via lattice Monte Carlo simulations, for possible neutral vector\nbosons in the Higgs region, apart from the photon and Z. There are numerical\nindications of a \"light Z\" in the lattice data (along with the photon and the\nZ), but a lack of the expected scaling of the light mass particle excludes any\nfirm conclusions about the physical spectrum.",
        "positive": "Transport Coefficient of Gluon Plasma from Lattice QCD: In this report we present our calculation of the transport coefficient of\ngluon system on $24^3\\times 8$ lattice in the quench approximation. Simulations\nare carried out in the range, $1.4 \\le T/T_c \\le 24$. In the temperature region\nslightly above the transition, where the perturbative calculation is not\napplicable, the shear viscosity($\\eta$) is smaller than typical hadron masses.\nThe bulk viscosity is consistent with zero within the range of error bars in\n$1.4 \\le T/T_c \\le 24$. We compare our results with the perturbative\ncalculations in large $T/T_c$ region. It is found that the lattice and\nperturbative results are consistent with each other there. The ratio $\\eta/s$\nis around $0.1-0.4$ in $T/T_c < 3$ region and satisfies the KSS\nbound\\cite{KSS}. In order to estimate the contribution from high frequency part\nof the spectral function, we study the effects of a term $\\rho^{high}$ proposed\nby Aarts and Resco\\cite{Aarts}. It is found that until the threshold mass\nbecomes small, its effect is quite small, and that viscosity decreases as the\nthreshold decreases. From these studies we think that although our result is\nobtained under an assumptions for the spectral function, it gives a reasonable\nestimation for $\\eta$($=\\pi d\\rho/d\\omega$ at $\\omega=0$), and qualitative\nresults will not be changed when the accurate spectral function is obtained."
    },
    {
        "anchor": "Lattice QCD study of the $H$ dibaryon using hexaquark and two-baryon\n  interpolators: We present a lattice QCD spectroscopy study in the isospin singlet,\nstrangeness $-2$ sectors relevant for the conjectured $H$ dibaryon. We employ\nboth local and bilocal interpolating operators to isolate the ground state in\nthe rest frame and in moving frames. Calculations are performed using two\nflavors of O($a$)-improved Wilson fermions and a quenched strange quark. Our\ninitial point-source method for constructing correlators does not allow for\nbilocal operators at the source; nevertheless, results from using these\noperators at the sink indicate that they provide an improved overlap onto the\nground state in comparison with the local operators. We also present results,\nin the rest frame, using a second method based on distillation to compute a\nhermitian matrix of correlators with bilocal operators at both the source and\nthe sink. This method yields a much more precise and reliable determination of\nthe ground-state energy. In the flavor-SU(3) symmetric case, we apply\nL\\\"uscher's finite-volume quantization condition to the rest-frame and\nmoving-frame energy levels to determine the $S$-wave scattering phase shift,\nnear and below the two-particle threshold. For a pion mass of 960 MeV, we find\nthat there exists a bound $H$ dibaryon with binding energy\n${\\Delta}E=(19\\pm10)$ MeV. In the 27-plet (dineutron) sector, the finite-volume\nanalysis suggests that the existence of a bound state is unlikely.",
        "positive": "$m_B$ and $f_{B^{(\\star)}}$ in $2+1$ flavour QCD from a combination of\n  continuum limit static and relativistic results: We present preliminary results for B-physics from a combination of\nnon-perturbative results in the static limit with relativistic computations\nsatisfying $am_{\\mathrm{heavy}}\\ll 1$. Relativistic measurements are carried\nout at the physical b-quark mass using the Schr\\\"{o}dinger Functional in a $0.5\n\\ \\mathrm{fm}$ box. They are connected to large volume observables through step\nscaling functions that trace the mass dependence between the physical charm\nregion and the static limit, such that B-physics results can be obtained by\ninterpolation; the procedure is designed to exactly cancel the troublesome\n$\\alpha_s(m_{\\mathrm{heavy}})^{n+\\gamma}$ corrections to large mass scaling.\nLarge volume computations for both static and relativistic quantities use CLS\n$N_f=2+1$ ensembles at $m_u=m_d=m_s$, and with five values of the lattice\nspacing down to $0.039$ fm. Our preliminary results for the b-quark mass and\nleptonic decay constants have competitive uncertainties, which are furthermore\ndominated by statistics, allowing for substantial future improvement. Here we\nfocus on numerical results, while the underlying strategy is discussed in a\ncompanion contribution."
    },
    {
        "anchor": "An implementation of hybrid parallel CUDA code for the hyperonic nuclear\n  forces: We present our recent effort to develop a GPGPU program to calculate 52\nchannels of the Nambu-Bethe-Salpeter (NBS) wave functions in order to study the\nbaryon interactions, from nucleon-nucleon to $\\Xi-\\Xi$, from lattice QCD. We\nadopt CUDA programming to perform the multi-GPU execution on a hybrid parallel\nprogramming with MPI and OpenMP. Effective baryon block algorithm is briefly\noutlined, which calculates efficaciously a large number of NBS wave functions\nat a time, and three CUDA kernel programs are implemented to materialize the\neffective baryon block algorithm using GPUs on the single-program multiple-data\n(SPMD) programming model. In order to parallelize multiple GPUs, we take both\ntwo approaches by dividing the time dimension and by dividing the spatial\ndimensions. Performances are measured using HA-PACS supercomputer in University\nof Tsukuba, which includes NVIDIA M2090 and NVIDIA K20X GPUs. Strong scaling\nand weak scaling measured by using both M2090 and K20X GPUs are presented. We\nfind distinct difference between the M2090 and the K20X in the sustained\nperformance measurement of particular kernel executions which utilize the\ncudaStream objects.",
        "positive": "Upsilon and J/Psi Spectroscopy Using Clover Fermions in the Presence of\n  Dynamical Quarks: We calculate spin averaged splittings in the bottomonium and charmonium\nsystems using the clover action. We compare static and kinetic masses of\nheavy-heavy and heavy-light mesons and discuss the consistency of the results."
    },
    {
        "anchor": "Screening masses towards chiral limit: A possible effective restoration of the anomalous $U_A(1)$ symmetry would\nhave a non-trivial effect on the global phase diagram of QCD. In this work we\ninvestigate the effective restoration of the $U_A(1)$ through the calculation\nof scalar and pseudo-scalar screening masses and corresponding\nsusceptibilities, for physical and lower than physical pion masses.\nCalculations have been performed in (2+1)-flavor HISQ discretization scheme\nwith a physical value of the strange quark mass. Preliminary calculations of\nthe continuum extrapolated scalar and pseudo-scalar masses are presented, based\non lattices with three different temporal extent. Non-trivial structure of the\ndifference between scalar and pseudo-scalar susceptibilites are discussed for\n$N_\\tau=8$ lattices.",
        "positive": "Hindered M1 Radiative Decay of $\u03a5(2S)$ from Lattice NRQCD: We present a calculation of the hindered M$1$ $\\Upsilon(2S) \\to \\eta_b(1S)\n\\gamma$ decay rate using lattice non-relativistic QCD. The calculation includes\nspin-dependent relativistic corrections to the NRQCD action through\n$\\mathcal{O}(v^6)$ in the quark's relative velocity, relativistic corrections\nto the leading order current which mediates the transition through the quark's\nmagnetic moment, radiative corrections to the leading spin-magnetic coupling\nand for the first time a full error budget. We also use gluon field ensembles\nat multiple lattice spacing values, all of which include $u$, $d$, $s$ and $c$\nquark vacuum polarisation. Our result for the branching fraction is\n$\\mathcal{B}(\\Upsilon(2S)\\to\\eta_b(1S)\\gamma) = 5.4(1.8)\\times 10^{-4} $, which\nagrees with the current experimental value."
    },
    {
        "anchor": "Simulating low dimensional QCD with Lefschetz thimbles: Non-perturbative lattice QCD calculations at non vanishing baryon number\ndensity are hampered by the QCD sign problem. The path integral, that in\nlattice QCD is calculated numerically, becomes highly oscillating. One possible\nsolution is the Lefschetz thimble approach. It requires a deformation of the\noriginal integration domain into a manifold embedded in complex space. For\nproperly chosen integration manifolds (\"thimbles\") the sign problem is\ndrastically alleviated. For some bosonic and fermionic models this approach has\nbeen shown to work. Here we apply the thimble disretization to\n(0+1)-dimensional QCD with standard staggerd quarks and disscuss issues that\nmay arrise in higher dimensions.",
        "positive": "Complex structure of a DT surface with $T^2$ topology: A method of defining the complex structure(moduli) for dynamically\ntriangulated(DT) surfaces with torus topology is proposed. Distribution of the\nmoduli parameter is measured numerically and compared with the Liouville theory\nfor the surface coupled to c = 0, 1 and 2 matter. Equivalence between the\ndynamical triangulation and the Liouville theory is established in terms of the\ncomplex structure."
    },
    {
        "anchor": "An FPGA-based Torus Communication Network: We describe the design and FPGA implementation of a 3D torus network (TNW) to\nprovide nearest-neighbor communications between commodity multi-core\nprocessors. The aim of this project is to build up tightly interconnected and\nscalable parallel systems for scientific computing. The design includes the\nVHDL code to implement on latest FPGA devices a network processor, which can be\naccessed by the CPU through a PCIe interface and which controls the external\nPHYs of the physical links. Moreover, a Linux driver and a library implementing\ncustom communication APIs are provided. The TNW has been successfully\nintegrated in two recent parallel machine projects, QPACE and AuroraScience. We\ndescribe some details of the porting of the TNW for the AuroraScience system\nand report performance results.",
        "positive": "Can the Couplings in the Fermion-Higgs Sector of the Standard Model be\n  Strong?: We present results for the renormalized quartic self-coupling $\\lambda_R$ and\nthe Yukawa coupling $y_R$ in a lattice fermion-Higgs model with two SU(2)$_L$\ndoublets, mostly for large values of the bare couplings. One-component\n(`reduced') staggered fermions are used in a numerical simulation with the\nHybrid Monte Carlo algorithm. The fermion and Higgs masses and the renormalized\nscalar field expectation value are computed on $L^3 24$ lattices, where $L$\nranges from $6$ to $16$. In the scaling region these quantities are found to\nhave a $1/L^2$ dependence, which is used to determine their values in the\ninfinite volume limit. We then calculate the $y_R$ and $\\lambda_R$ from their\ntree level definitions in terms of the masses and renormalized scalar field\nexpectation value, extrapolated to infinite volume. The scalar field\npropagators can be described for momenta up to the cut-off by one fermion loop\nrenormalized perturbation theory and the results for $\\lambda_R$ and $y_R$ come\nout to be close to the tree level unitarity bounds. There are no signs that are\nin contradiction with the triviality of the Yukawa and quartic self-coupling."
    },
    {
        "anchor": "Improved Wilson QCD simulations at light quark masses: We present preliminary results from UKQCD simulations at light quark masses\nusing two flavours of non-pertubatively improved Wilson fermions. We report on\nthe performance of the standard HMC algorithm at these quark masses where\nm_pi/m_rho < 0.5 in comparison with simulations using improved staggered\nquarks.",
        "positive": "Theta-vacuum systems via real action simulations: Inspired by the results of the Ising model within an imaginary external\nmagnetic field, we introduce a transformation in quantum systems with a\ntheta-vacuum term that amounts to a rescaling of z=cos(theta/2). Making use of\nthis transformation we are able to determine the order parameter as a function\nof theta. The approach is successfully tested in models with both broken and\nunbroken CP symmetry at theta=pi."
    },
    {
        "anchor": "Meson spectrum of Sp(4) lattice gauge theory with two fundamental Dirac\n  fermions: We calculate the meson spectrum of the Sp(4) lattice gauge theory coupled to\ntwo fundamental flavours of dynamical Dirac fermions. We focus on some of the\nlightest (flavoured) spin-0 and spin-1 states. This theory provides an\nultraviolet completion for composite Higgs models based upon the SU(4)/Sp(4)\ncoset. We analyse the strongly coupled dynamics in isolation, without explicit\ncoupling to the standard model. We carry out continuum extrapolations using\ndynamical ensembles generated at five different values of bare lattice\ncoupling, and for several values of the bare fermion mass. We fit the resulting\nmeson masses and decay constants to a low-energy effective field theory built\nalong the ideas of hidden local symmetry. We also compare our results to those\nof other closely related lattice gauge theories, which have matter content\nconsisting of two fundamental Dirac flavours.",
        "positive": "Lattice simulations of QCD-like theories at non-zero density: One way of avoiding the complex action problem in lattice QCD at non-zero\ndensity is to simulate QCD-like theories with a real action, such as two-colour\nQCD. The symmetries of two-colour QCD with quarks in the fundamental and in the\nadjoint representation are described, and the status of lattice simulations is\nreviewed, with particular emphasis on comparison with predictions from chiral\nperturbation theory. Finally, we discuss how the lessons from two-colour QCD\nmay be carried over to physical QCD."
    },
    {
        "anchor": "The infrared behaviour of the gluon propagator from lattice QCD: The gluon propagator in the Landau gauge is calculated in quenched QCD on a\nlarge lattice (32^3x64) at beta=6.0. In order to assess finite volume and\nfinite lattice spacing artefacts, we also calculate the propagator on a smaller\nvolume for two different values of the lattice spacing. New structure seen in\nthe infrared region survives conservative cuts to the lattice data, and serves\nto exclude a number of models that have appeared in the literature.",
        "positive": "Numerical Study of the Roberge-Weiss Transition: We study the Roberge-Weiss phase transition numerically. The phase transition\nis associated with the discontinuities in the quark-number density at specific\nvalues of imaginary quark chemical potential. We parameterize the quark number\ndensity $\\rho_q$ by the polynomial fit function to compute the canonical\npartition functions. We demonstrate that this approach provides a good\nframework for analyzing lattice QCD data at finite density and a high\ntemperature. We show numerically that at high temperature, the Lee-Yang zeros\nlie on the negative real semi-axis provided that the high-quark-number\ncontributions to the grand canonical partition function are taken into account.\nThese Lee-Yang zeros have nonzero linear density, which signals the\nRoberge-Weiss phase transition. We demonstrate that this density agrees with\nthe quark density discontinuity at the transition line."
    },
    {
        "anchor": "Introduction to Non-perturbative Heavy Quark Effective Theory: Lectures given at the Summer School on \"Modern perspectives in lattice QCD\",\nLes Houches, August 3-28, 2009",
        "positive": "Analytic expansions of two- and three-particle excited-state energies: The last years have seen significant developments in methods relating two-\nand three-particle finite-volume energies to scattering observables. These\nrelations hold for both weakly and strongly interacting systems, and studying\ntheir predictions in limiting cases can provide important cross checks as well\nas giving useful insights into the general formulae. In these proceedings, we\npresent analytic results for finite-volume excited states, recovered by\nexpanding the general relations in powers of the interaction strength. We\nhighlight elegant patterns that emerge, especially for excited three-particle\nenergies, and discuss various applications of the results. The two-particle\nresults summarized here are described in more detail in the full manuscript,\nand the three-particle results are detailed in a manuscript to appear."
    },
    {
        "anchor": "Two-color QCD with staggered fermions at finite temperature under the\n  influence of a magnetic field: In this paper we investigate the influence of a constant external magnetic\nfield on the finite-temperature phase structure and the chiral properties of a\nsimplified lattice model for QCD. We assume an SU(2) gauge symmetry and employ\ndynamical staggered fermions of identical mass without rooting, corresponding\nto Nf=4 flavors of identical electric charge. For fixed mass (given in lattice\nunits) the critical temperature is seen to rise with the magnetic field\nstrength. For three fixed beta-values, selected such that we stay (i) within\nthe chirally broken phase, (ii) within the transition region or (iii) within\nthe chirally restored phase, we study the approach to the chiral limit for\nvarious values of the magnetic field. Within the chirally broken (confinement)\nphase the chiral condensate is found to increase monotonically with a growing\nmagnetic field strength. In the chiral limit the increase starts linear in\nagreement with a chiral model studied by Shushpanov and Smilga. Within the\nchirally restored (deconfinement) phase the chiral condensate tends to zero in\nthe chiral limit, irrespective of the strength of the magnetic field.",
        "positive": "Towards extremely dense matter on the lattice: QCD is expected to have a rich phase structure. It is empirically known to be\ndifficult to access low temperature and nonzero chemical potential $\\mu$\nregions in lattice QCD simulations. We address this issue in a lattice QCD with\nthe use of a dimensional reduction formula of the fermion determinant.\n  We investigate spectral properties of a reduced matrix of the reduction\nformula. Lattice simulations with different lattice sizes show that the\neigenvalues of the reduced matrix follow a scaling law for the temporal size\n$N_t$. The properties of the fermion determinant are examined using the\nreduction formula. We find that as a consequence of the $N_t$ scaling law, the\nfermion determinant becomes insensitive to $\\mu$ as $T$ decreases, and\n$\\mu$-independent at T=0 for $\\mu<m_\\pi/2$.\n  The $N_t$ scaling law provides two types of the low temperature limit of the\nfermion determinant: (i) for low density and (ii) for high-density. The fermion\ndeterminant becomes real and the theory is free from the sign problem in both\ncases. In case of (ii), QCD approaches to a theory, where quarks interact only\nin spatial directions, and gluons interact via the ordinary Yang-Mills action.\nThe partition function becomes exactly $Z_3$ invariant even in the presence of\ndynamical quarks because of the absence of the temporal interaction of quarks.\n  The reduction formula is also applied to the canonical formalism and Lee-Yang\nzero theorem. We find characteristic temperature dependences of the canonical\ndistribution and of Lee-Yang zero trajectory. Using an assumption on the\ncanonical partition function, we discuss physical meaning of those temperature\ndependences and show that the change of the canonical distribution and Lee-Yang\nzero trajectory are related to the existence/absence of $\\mu$-induced phase\ntransitions."
    },
    {
        "anchor": "Lattice QCD study of the Boer-Mulders effect in a pion: The three-dimensional momenta of quarks inside a hadron are encoded in\ntransverse momentum-dependent parton distribution functions (TMDs). This work\npresents an exploratory lattice QCD study of a TMD observable in the pion\ndescribing the Boer-Mulders effect, which is related to polarized quark\ntransverse momentum in an unpolarized hadron. Particular emphasis is placed on\nthe behavior as a function of a Collins-Soper evolution parameter quantifying\nthe relative rapidity of the struck quark and the initial hadron, e.g., in a\nsemi-inclusive deep inelastic scattering (SIDIS) process. The lattice\ncalculation, performed at the pion mass m_pi = 518 MeV, utilizes a definition\nof TMDs via hadronic matrix elements of a quark bilocal operator with a\nstaple-shaped gauge connection; in this context, the evolution parameter is\nrelated to the staple direction. By parametrizing the aforementioned matrix\nelements in terms of invariant amplitudes, the problem can be cast in a Lorentz\nframe suited for the lattice calculation. In contrast to an earlier nucleon\nstudy, due to the lower mass of the pion, the calculated data enable\nquantitative statements about the physically interesting limit of large\nrelative rapidity. In passing, the similarity between the Boer-Mulders effects\nextracted in the pion and the nucleon is noted.",
        "positive": "The Infrared behavior of SU(3) Nf=12 gauge theory -about the existence\n  of conformal fixed point-: Incorporated with twisted boundary condition, Polyakov loop correlators can\ngive a definition of the renormalized coupling. We employ this scheme for the\nstep scaling method (with step size s = 2) in the search of conformal fixed\npoint of SU(3) gauge theory with 12 massless flavors. Staggered fermion and\nplaquette gauge action are used in the lattice simulation with six different\nlattice sizes, L/a = 20, 16, 12, 10, 8 and 6. For the largest lattice size, L/a\n= 20, we used a large number of Graphics Processing Units (GPUs) and\naccumulated 3,000,000 trajectories in total. We found that the step scaling\nfunction sigma (u) is consistent with u in the low-energy region. This means\nthe existence of conformal fixed point. Some details of our analysis and\nsimulations will also be presented."
    },
    {
        "anchor": "One-loop matching for quark dipole operators in a gradient-flow scheme: The quark chromoelectric dipole (qCEDM) operator is a CP-violating operator\ndescribing, at hadronic energies, beyond-the-standard-model contributions to\nthe electric dipole moment of particles with nonzero spin. In this paper we\ndefine renormalized dipole operators in a regularization-independent scheme\nusing the gradient flow, and we perform the matching at one loop in\nperturbation theory to renormalized operators of the same and lower dimension\nin the more familiar MS scheme. We also determine the matching coefficients for\nthe quark chromomagnetic dipole operator (qCMDM), which contributes, for\nexample, to matrix elements relevant to CP-violating and CP-conserving kaon\ndecays. The calculation provides a basis for future lattice QCD computations of\nhadronic matrix elements of the qCEDM and qCMDM operators.",
        "positive": "Two-current correlations and DPDs for the nucleon on the lattice: We calculate correlation functions of two local operators within the nucleon\ncarrying momentum. We resolve their dependence on the spatial distance of the\ncurrents. This is carried out for all Wick contractions, taking into account\nseveral operator insertion types. The resulting four-point functions can be\nrelated to parton distribution functions as well as to Mellin moments of double\nparton distributions. For the latter, we analyze their quark spin and flavor\ndependency. In this first study, we employ an $N_F = 2 + 1$ CLS ensemble on a\n$96 \\times 32^3$ lattice with lattice spacing $a = 0.0856\\ \\mathrm{fm}$ and the\npseudoscalar masses $m_\\pi = 355\\ \\mathrm{MeV}$ and $m_K = 441\\ \\mathrm{MeV}$."
    },
    {
        "anchor": "Phenomenological Models of the Quark-Gluon Plasma Equation of State: Two phenomenological models describing an SU(N) quark-gluon plasma are\npresented. The first is obtained from high temperature expansions of the free\nenergy of a massive gluon, while the second is derived by demanding color\nneutrality over a certain length scale. Each model has a single free parameter,\nexhibits behavior similar to lattice simulations over the range T_d-5T_d, and\nhas the correct blackbody behavior for large temperatures. The N=2\ndeconfinement transition is second order in both models, while N=3,4, and 5 are\nfirst order. Both modelsappear to have a smooth large-N limit. In both models,\nthe confined phase is characterized by a mutual repulsion of Polyakov loop\neigenvalues that makes the Polyakov loop expectation value zero. In the\ndeconfined phase, the rotation of the eigenvalues in the complex plane towards\n1 is responsible for the approach to the blackbody limit over the range\nT_d-5T_d. The addition of quarks in SU(3) breaks Z(3) symmetry weakly and\neliminates the deconfining phase transition for sufficiently light quarks.",
        "positive": "Lattice study of the leptonic decay constant of the pion and its\n  excitations: We present a calculation of the decay constant of the pion, and its\nlowest-lying three excitations, at three values of the pion mass between around\n400 and 700 MeV, using anisotropic clover lattices. We use the variational\nmethod to determine an optimal interpolating operator for each of the states.\nWe find that the decay constant of the first excitation, and more notably of\nthe second, is suppressed with respect to that of the ground-state pion, but\nthat the suppression shows little dependence on the quark mass."
    },
    {
        "anchor": "Fun with Dirac eigenvalues: It is popular to discuss low energy physics in lattice gauge theory in terms\nof the small eigenvalues of the lattice Dirac operator. I play with some\nensuing pitfalls in the interpretation of these eigenvalue spectra.",
        "positive": "Neutral kaon mixing from new physics: matrix elements in $N_f=2+1$ QCD: We present results for matrix elements of $\\Delta S=2$ four-fermion operators\narising generically in models of new physics. These are needed to constrain\nsuch models using the measured values of $\\varepsilon_K$ and $\\Delta M_K$. We\nuse lattice QCD with 2+1 flavors of improved staggered fermions on lattices\ngenerated by the MILC collaboration. We extrapolate to the continuum from three\nlattice spacings ranging down to $a\\approx 0.045\\;$fm. Total errors are $\\sim\n5-6%$, arising primarily from our use of one-loop matching between lattice and\ncontinuum operators. For two of the matrix elements, our results disagree\nsignificantly from those obtained using different fermion discretizations."
    },
    {
        "anchor": "Pion valence quark PDF from lattice QCD: We present lattice results on the valence-quark structure of the pion using a\ncoordinate space method within the framework of Large Momentum Effective Theory\n(LaMET). In this method one relies on the matrix elements of a Euclidean\ncorrelator in boosted hadronic states, which have an operator product expansion\nat short distance that allows us to extract the moments of PDFs. We renormalize\nthe Euclidean correlator by forming the reduced Ioffe-time distribution (rITD),\nand reconstruct the second and fourth moments of the pion PDF by taking into\naccount of QCD evolution effects.",
        "positive": "Electromagnetic corrections to leptonic decay rates of charged\n  pseudoscalar mesons: finite-volume effects: In Carrasco et al. we have recently proposed a method to calculate $O(e^2)$\nelectromagnetic corrections to leptonic decay widths of pseudoscalar mesons.\nThe method is based on the observation that the infrared divergent\ncontributions (that appear at intermediate stages of the calculation and that\ncancel in physical quantities thanks to the Bloch-Nordsieck mechanism) are\nuniversal, i.e. depend on the charge and the mass of the meson but not on its\ninternal structure. In this talk we perform a detailed analysis of the\nfinite-volume effects associated with our method. In particular we show that\nalso the leading $1/L$ finite-volume effects are universal and perform an\nanalytical calculation of the finite-volume leptonic decay rate for a\npoint-like meson."
    },
    {
        "anchor": "Properties of the Abelian Projection Fields in $SU(N)$ Lattice\n  Gluodynamics: 't~Hooft's abelian projection of $SU(N)$ gauge theory yields $N$ mutually\nconstrained, compact abelian fields which are permutationally equivalent. We\nformulate the notion of ``species permutation'' symmetry of the $N$ abelian\nprojection fields and discuss its consequences for cross-species correlators.\nWe show that at large $N$ cross-species interactions are ${1\\over N}$\nsuppressed relative to same-species interactions. Numerical simulations at\n$N=3$ support our symmetry arguments and reveal the existence of inter-species\ninteractions of size ${\\cal O\\/}\\bigl({1\\over N-1}\\bigr)$ as analytically\npredicted.",
        "positive": "Axial Charges of Octet Baryons in Two-flavor Lattice QCD: We evaluate the strangeness-conserving $N N$, $\\Sigma\\Sigma$, $\\Xi\\Xi$,\n$\\Lambda\\Sigma$ and the strangeness-changing $\\Lambda N$, $\\Sigma N$,\n$\\Lambda\\Xi$, $\\Sigma\\Xi$ axial charges in lattice QCD with two flavors of\ndynamical quarks and extend our previous work on\npseudoscalar-meson-octet-baryon coupling constants so as to include\n$\\pi\\Xi\\Xi$, $K\\Lambda\\Xi$ and $K\\Sigma\\Xi$ coupling constants. We find that\nthe axial charges have rather weak quark-mass dependence and the breaking in\nSU(3)-flavor symmetry is small at each quark-mass point we consider."
    },
    {
        "anchor": "Running of the SF-coupling with four massless flavours: We discuss the status of different determinations of alpha_s, motivating a\nprecise and reliable computation from lattice QCD. In order to suppress\nperturbative errors, the non-perturbative computation has to reach high energy\nscales mu. Such results already exist in the SF-scheme for N_f=0,2 and N_f=3.\nWe recently added the running with four massless flavours in a range of alpha\nfrom about 0.07 to 0.3 . It is based on our recent determination of the\nSheikholeslami Wohlert coefficient in the four-flavour theory.",
        "positive": "The Nature of the Hadronic String: We study a closed hadronic string using pure glue lattice simulation. We\nmeasure the energy of the flux state encircling the periodic boundary condition\n(the torelon). From these data we deduce the string fluctuation component and\ncompare with models for the hadronic string. [The TEX source file is also\navailable by anonymous ftp from suna.amtp.liv.ac.uk in directory pub/cmi ]"
    },
    {
        "anchor": "A way to estimate the heavy quark thermalization rate from the lattice: The thermalization rate of a heavy quark is related to its momentum diffusion\ncoefficient. Starting from a Kubo relation and using the framework of the heavy\nquark effective theory, we argue that in the large-mass limit the momentum\ndiffusion coefficient can be defined through a certain Euclidean correlation\nfunction, involving color-electric fields along a Polyakov loop. Furthermore,\ncarrying out a perturbative computation, we demonstrate that the spectral\nfunction corresponding to this correlator is relatively flat at small\nfrequencies. Therefore, unlike in the case of several other transport\ncoefficients, for which the narrowness of the transport peak makes analytic\ncontinuation from Euclidean lattice data susceptible to severe systematic\nuncertainties, it appears that the determination of the heavy quark\nthermalization rate could be relatively well under control.",
        "positive": "New way of collision experiment data analysis based on Grand Canonical\n  Distribution and Lattice QCD data: We propose new way of heavy ion collisions experiment data analysis. We\nanalyze physical parameters of fireball created in RHIC experiment based on\nGrand Canonical Distribution and different Lattice QCD data available at the\nmoment. Our results on chemical potential are in agreement with previous model\nestimations and do not depend on Lattice setup. At same time, we found possible\nT(V) states of fireball and estimated the most probable temperature and volume\nof fireball as function of collision energy. We conclude that hadrom matter at\nRHIC experiment is thermalized and described by Grand Canonical Distribution."
    },
    {
        "anchor": "Deflation as a Method of Variance Reduction for Estimating the Trace of\n  a Matrix Inverse: Many fields require computing the trace of the inverse of a large, sparse\nmatrix. The typical method used for such computations is the Hutchinson method\nwhich is a Monte Carlo (MC) averaging over matrix quadratures. To improve its\nconvergence, several variance reductions techniques have been proposed. In this\npaper, we study the effects of deflating the near null singular value space. We\nmake two main contributions.\n  First, we analyze the variance of the Hutchinson method as a function of the\ndeflated singular values and vectors. Although this provides good intuition in\ngeneral, by assuming additionally that the singular vectors are random unitary\nmatrices, we arrive at concise formulas for the deflated variance that include\nonly the variance and mean of the singular values. We make the remarkable\nobservation that deflation may increase variance for Hermitian matrices but not\nfor non-Hermitian ones. This is a rare, if not unique, property where\nnon-Hermitian matrices outperform Hermitian ones. The theory can be used as a\nmodel for predicting the benefits of deflation.\n  Second, we use deflation in the context of a large scale application of\n\"disconnected diagrams\" in Lattice QCD. On lattices, Hierarchical Probing (HP)\nhas previously provided an order of magnitude of variance reduction over MC by\nremoving \"error\" from neighboring nodes of increasing distance in the lattice.\nAlthough deflation used directly on MC yields a limited improvement of 30% in\nour problem, when combined with HP they reduce variance by a factor of over 60\ncompared to MC. For this, we pre-computated 1000 smallest singular values of an\nill-conditioned matrix of size 25 million. Using PRIMME and a domain-specific\nAlgebraic Multigrid preconditioner, we perform one of the largest eigenvalue\ncomputations in Lattice QCD at a fraction of the cost of our trace computation.",
        "positive": "Abelian representation for nonabelian Wilson loops and the Non - Abelian\n  Stokes theorem on the lattice: We derive the Abelian - like expression for the lattice SU(N) Wilson loop in\narbitrary irreducible representation. The continuum Abelian representation of\nthe SU(N) Wilson loop (for the loop without selfintersections) that has been\nobtained by Diakonov and Petrov appears to be a continuum limit of this\nexpression. We also obtain the lattice variant of a non - Abelian Stokes\ntheorem and present the explicit expression for the matrix $\\cal H$ used in the\nDiakonov - Petrov approach."
    },
    {
        "anchor": "Lattice study of R\u00e9nyi entanglement entropy in $SU(N_c)$ lattice\n  Yang-Mills theory with $N_c = 2, 3, 4$: We consider the second R\\'enyi entropy $S^{(2)}$ in pure lattice gauge theory\nwith $SU(2)$, $SU(3)$ and $SU(4)$ gauge groups, which serves as a first\napproximation for the entanglement entropy and the entropic $C$-function. We\ncompare the results for different gauge groups using scale setting via the\nstring tension. We confirm that at small distances $l$ our approximation for\nthe entropic $C$-function $C(l)$, calculated for the slab-shaped entangled\nregion of width $l$, scales as $N_c^2 - 1$ in accordance with its\ninterpretation in terms of free gluons. At larger distances $l$ $C(l)$ is found\nto approach zero for $N_c = 3, 4$, somewhat more rapidly for $N_c = 4$ than for\n$N_c = 3$. This finding supports the conjectured discontinuity of the entropic\n$C$-function in the large-$N$ limit, which was found in the context of AdS/CFT\ncorrespondence and which can be interpreted as transition between colorful\nquarks and gluons at small distances and colorless confined states at long\ndistances. On the other hand, for $SU(2)$ gauge group the long-distance\nbehavior of the entropic $C$-function is inconclusive so far. There exists a\nsmall region of lattice spacings yielding results consistent with $N_c=3,4$,\nwhile results from other lattice spacings deviate without clear systematics. We\ndiscuss several possible causes for discrepancies between our results and the\nbehavior of entanglement entropy in holographic models.",
        "positive": "Heavy-light meson decay constants from NRQCD: an analysis of the 1/M\n  corrections: We present {\\it preliminary} results for the decay constants of heavy-light\nmesons using NRQCD heavy and tadpole improved Clover light quarks. A comparison\nis made with data obtained using Wilson light quarks. We present an analysis of\nthe 1/M corrections to the decay constants in the static limit and compare with\nthe predictions of HQET."
    },
    {
        "anchor": "Precision study of the SU(3) topological susceptibility in the continuum: We determine the topological susceptibility in the SU(3) pure gauge theory.\nWe perform a series of high-statistics lattice studies and take the combined\ncontinuum and infinite volume limit. We find chi_{top}r_0^4=0.0524(7)(6) which\ntranslates into chi_{top}^{1/4}=193(1)(8)MeV with the second error exclusively\ndue to the intrinsic scale ambiguity.",
        "positive": "Iterating Block Spin Transformations of the O(3) Non-Linear Sigma-Model: We study the iteration of block spin transformations in the O(3) symmetric\nnon-linear sigma-model on a two-dimensional square lattice with help of the\nMonte Carlo method. In contrast to the classical Monte Carlo Renormalization\nGroup approach, we do attempt to explicitly compute the block spin effective\nactions. Using two different methods for the determination of effective\ncouplings, we study the renormalization group flow for various parametrization\nand truncation schemes. The largest ansatz for the effective action contains\nthirteen coupling constants.\n  Actions on the renormalized trajectory should describe theories with no\nlattice artefacts, even at small correlation length. However, tests with the\nstep scaling function of Luescher et al. reveal that our truncated effective\nactions show sizable scaling violations indicating that the ansaetze are still\ntoo small."
    },
    {
        "anchor": "Improved Lattice Spectroscopy of Minimal Walking Technicolor: We present a numerical study of spectroscopic observables in the SU(2) gauge\ntheory with two adjoint fermions using improved source and sink operators. We\ncompare in detail our improved results with previous determinations of masses\nthat used point sources and sinks and we investigate possible systematic\neffects in both cases. Such comparison enables us to clearly assess the impact\nof a short temporal extent on the physical picture, and to investigate some\neffects due to the finite spatial box. While confirming the IR-conformal\nbehaviour of the theory, our investigation shows that in order to make firm\nquantitative predictions, a better handle on finite size effects is needed.",
        "positive": "Non-Perturbative Renormalisation of Composite Operators: It is shown that the renormalisation constants of two quark operators can be\naccurately determined (to a precision of a few per-cent using 18 gluon\nconfigurations) using Chiral Ward identities. A method for computing\nrenormalisation constants of generic composite operators without the use of\nlattice perturbation theory is proposed."
    },
    {
        "anchor": "Shadow Hamiltonians, Poisson Brackets, and Gauge Theories: Numerical lattice gauge theory computations to generate gauge field\nconfigurations including the effects of dynamical fermions are usually carried\nout using algorithms that require the molecular dynamics evolution of gauge\nfields using symplectic integrators. Sophisticated integrators are in common\nuse but are hard to optimise, and force-gradient integrators show promise\nespecially for large lattice volumes. We explain why symplectic integrators\nlead to very efficient Monte Carlo algorithms because they exactly conserve a\nshadow Hamiltonian. The shadow Hamiltonian may be expanded in terms of Poisson\nbrackets, and can be used to optimize the integrators. We show how this may be\ndone for gauge theories by extending the formulation of Hamiltonian mechanics\non Lie groups to include Poisson brackets and shadows, and by giving a general\nmethod for the practical computation of forces, force-gradients, and Poisson\nbrackets for gauge theories.",
        "positive": "On the eta-invariant in the four dimensional chiral U(1) theory: The imaginary part of the effective action is investigated in the 4D chiral\nU(1) theory using the CFA."
    },
    {
        "anchor": "The ratio FK/Fpi in QCD: We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based\non a series of lattice calculations with three different lattice spacings,\nlarge volumes and a simulated pion mass reaching down to about 190 MeV. We\nobtain FK/Fpi=1.192 +/- 0.007(stat) +/- 0.006(syst). This result is then used\nto give an updated value of the CKM matrix element |Vus|. The unitarity\nrelation for the first row of this matrix is found to be well observed.",
        "positive": "Finite-Volume Two-Pion Amplitudes in the I=0 Channel: We perform a calculation in one-loop chiral perturbation theory of the\ntwo-pion matrix elements and correlation functions of an I=0 scalar operator,\nin finite and infinite volumes for both full and quenched QCD. We show that\nmajor difficulties arise in the quenched theory due to the lack of unitarity.\nSimilar problems are expected for quenched lattice calculations of $K \\to \\pi\n\\pi$ amplitudes with $\\Delta I=1/2$. Our results raise the important question\nof whether it is consistent to study $K\\to\\pi\\pi$ amplitudes beyond leading\norder in chiral perturbation theory in quenched or partially quenched QCD."
    },
    {
        "anchor": "A Two-Dimensional Lattice Model with Exact Supersymmetry: Starting from a simple discrete model which exhibits a supersymmetric\ninvariance we construct a local, interacting, two-dimensional Euclidean lattice\ntheory which also admits an exact supersymmetry. This model is shown to\ncorrespond to the Wess-Zumino model with extended N=2 supersymmetry in the\ncontinuum. We have performed dynamical fermion simulations to check the\nspectrum and supersymmetric Ward identities and find good agreement with\ntheory.",
        "positive": "P- and D-wave spin-orbit splittings in heavy-light mesons: This is a summary of a detailed study of heavy-light meson excited state\nenergies. Our lattice measurements include both radial and orbital excitations.\nParticular attention is paid to the spin-orbit splittings, to see which one of\nthe states (for a given angular momentum L) has the lower energy. In nature the\nclosest equivalent of this heavy-light system is the B_s meson, which allows us\nto compare our lattice calculations to experimental results (where available)\nor give a prediction where the excited states, particularly P-wave states,\nshould lie."
    },
    {
        "anchor": "Isospin-breaking corrections to light-meson leptonic decays from lattice\n  simulations at physical quark masses: The decreasing uncertainties in theoretical predictions and experimental\nmeasurements of several hadronic observables related to weak processes, which\nin many cases are now smaller than $\\mathrm{O}(1\\%)$, require theoretical\ncalculations to include subleading corrections that were neglected so far.\nPrecise determinations of leptonic and semi-leptonic decay rates, including QED\nand strong isospin-breaking effects, can play a central role in solving the\ncurrent tensions in the first-row unitarity of the CKM matrix. In this work we\npresent the first RBC/UKQCD lattice calculation of the isospin-breaking\ncorrections to the ratio of leptonic decay rates of kaons and pions into muons\nand neutrinos. The calculation is performed with $N_\\mathrm{f}=2+1$ dynamical\nquarks close to the physical point and domain wall fermions in the M\\\"obius\nformulation are employed. Long-distance QED interactions are included according\nto the $\\mathrm{QED_L}$ prescription and the crucial role of finite-volume\nelectromagnetic corrections in the determination of leptonic decay rates, which\nproduce a large systematic uncertainty, is extensively discussed. Finally, we\nstudy the different sources of uncertainty on $|V_\\mathrm{us}|/|V_\\mathrm{ud}|$\nand observe that, if finite-volume systematics can be reduced, the error from\nisospin-breaking corrections is potentially sub-dominant in the final precision\nof the ratio of the CKM matrix elements.",
        "positive": "Four-dimensional Simulation of the Hot Electroweak Phase Transition with\n  the SU(2) Gauge-Higgs Model: We study the finite-temperature phase transition of the four-dimensional\nSU(2) gauge-Higgs model for intermediate values of the Higgs boson mass in the\nrange $50 \\lsim m_H \\lsim 100$GeV on a lattice with the temporal lattice size\n$N_t=2$. The order of the transition is systematically examined using finite\nsize scaling methods. Behavior of the interface tension and the latent heat for\nan increasing Higgs boson mass is also investigated."
    },
    {
        "anchor": "Leading order mesonic and baryonic SU(3) low energy constants from $N_f\n  = 3$ lattice QCD: We determine the leading order mesonic~($B_0$ and $F_0$) and baryonic~($m_0$,\n$D$ and $F$) SU(3) chiral perturbation theory low energy constants from lattice\nQCD. We employ gauge ensembles with $N_f=3$ (i.e., $m_u=m_d=m_s$)\nnon-perturbatively improved Wilson fermions at six distinct values of the\nlattice spacing in the range $a\\approx (0.039 - 0.098)$ fm, which constitute a\nsubset of the Coordinated Lattice Simulations (CLS) gauge ensembles. The\npseudoscalar meson mass $M_\\pi$ ranges from around $430$ MeV down to $240$ MeV\nand the linear spatial lattice extent $L$ from $6.4\\,M_{\\pi}^{-1}$ to\n$3.3\\,M_{\\pi}^{-1}$, where $ L M_\\pi \\geq 4$ for the majority of the ensembles.\nThis allows us to perform a controlled extrapolation of all the low energy\nconstants to the chiral, infinite volume and continuum limits. We find the\nSU(3) chiral condensate and $F_0$ to be smaller than their SU(2) counterparts\nwhile the Gell-Mann--Oakes--Renner parameters $B_0\\approx B$ are similar.\nRegarding baryonic LECs, we obtain $F/D = 0.612^{(14)}_{(12)}$.",
        "positive": "Hidden-charm Hexaquarks from Lattice QCD: We present a lattice QCD study of hidden-charm hexaquarks with quark content\n$usc\\bar{d}\\bar{s}\\bar{c}$ based on four ensembles of gauge configurations\ngenerated by CLQCD Collaboration with pion mass in the range of 220-300MeV.\nFour operators with quantum numbers $0^{++}, 0^{-+}, 1^{++}$ and $1^{--}$\nrespectively are constructed to interpolate the hexaquarks. After validating\nthe spectrum and the dispersion relation for ordinary hadrons, we calculate the\nmasses of the hexaquarks and extrapolate the results to the physical pion mass\nand the continuum limit. We find that the masses of the four hexaquarks are all\nbelow the $\\Xi_c \\bar \\Xi_c$ threshold, while the $0^{-+}$ hexaquark lies\naround the $\\eta_c K^+K^-$ threshold. These results will be helpful for\nexperimental searches in future and for a deep understanding of the nature of\nmultiquark states."
    },
    {
        "anchor": "A Lattice Calculation of Thermal Dilepton Rates: Using clover improved Wilson fermions we calculate thermal vector meson\ncorrelation functions above the deconfinement phase transition of quenched QCD.\nAt temperatures 1.5 Tc and 3Tc they are found to differ by less than 15% from\nthat of a freely propagating quark anti-quark pair. This puts severe\nconstraints on the dilepton production rate and in particular rules out a\nstrong divergence of the dilepton rate at low energies. The vector spectral\nfunction, which has been reconstructed using the Maximum Entropy Method, yields\nan enhancement of the dilepton rate over the Born rate of at most a factor two\nin the energy interval 4 < E/T < 8 and suggests that the spectrum is cut-off at\nlow energies by a thermal mass threshold of about (2-3)T.",
        "positive": "Percolation and Magnetization in the Continuous Spin Ising Model: In the strong coupling limit the partition function of SU(2) gauge theory can\nbe reduced to that of the continuous spin Ising model with nearest neighbour\npair-interactions. The random cluster representation of the continuous spin\nIsing model in two dimensions is derived through a Fortuin-Kasteleyn\ntransformation, and the properties of the corresponding cluster distribution\nare analyzed. It is shown that for this model, the magnetic transition is\nequivalent to the percolation transition of Fortuin-Kasteleyn clusters, using\nlocal bond weights. These results are also illustrated by means of numerical\nsimulations."
    },
    {
        "anchor": "Alpha_S from Upsilon Spectroscopy with Dynamical Wilson Fermions: We estimate the QCD coupling constant from a lattice calculation of the\nbottomonium spectrum. The second order perturbative expansion of the plaquette\nexpectation value is employed to determine alpha_S at a scale set by the 2S-1S\nand 1P-1S level splittings. The latter are computed in NRQCD in a dynamical\ngauge field background with two degenerate flavours of Wilson quarks at\nintermediate masses and extrapolated to the chiral limit. Combining the N_f=2\nresult with the quenched result at equal lattice spacing we extrapolate to the\nphysical number of light flavours to find a value of alpha_{\\bar MS}^{(5)}(m_Z)\n= 0.1118(17). The error quoted covers both statistical and systematic\nuncertainties in the scale determination. An additional 5% uncertainty comes\nfrom the choice of the underlying sea quark formulation and from truncation\nerrors in perturbative expansions.",
        "positive": "Universal correlations in spectra of the lattice QCD Dirac operator: Recently, Kalkreuter obtained complete Dirac spectra for $SU(2)$ lattice\ngauge theory both for staggered fermions and for Wilson fermions. The lattice\nsize was as large as $12^4$. We performed a statistical analysis of these data\nand found that the eigenvalue correlations can be described by the Gaussian\nSymplectic Ensemble for staggered fermions and by the Gaussian Orthogonal\nEnsemble for Wilson fermions. In both cases long range spectral fluctuations\nare strongly suppressed: the variance of a sequence of levels containing $n$\neigenvalues on average is given by $\\Sigma_2(n) \\sim 2 (\\log n)/\\beta\\pi^2 $\n($\\beta$ is equal to 4 and 1, respectively) instead of $\\Sigma_2(n) = n$ for a\nrandom sequence of levels. Our findings are in agreement with the anti-unitary\nsymmetry of the lattice Dirac operator for $N_c=2$ with staggered fermions\nwhich differs from Wilson fermions (with the continuum anti-unitary symmetry).\nFor $N_c = 3$, we predict that the eigenvalue correlations are given by the\nGaussian Unitary Ensemble."
    },
    {
        "anchor": "On the Feynman-Hellmann Theorem in Quantum Field Theory and the\n  Calculation of Matrix Elements: The Feynman-Hellmann theorem can be derived from the long Euclidean-time\nlimit of correlation functions determined with functional derivatives of the\npartition function. Using this insight, we fully develop an improved method for\ncomputing matrix elements of external currents utilizing only two-point\ncorrelation functions. Our method applies to matrix elements of any external\nbilinear current, including nonzero momentum transfer, flavor-changing, and two\nor more current insertion matrix elements. The ability to identify and control\nall the systematic uncertainties in the analysis of the correlation functions\nstems from the unique time dependence of the ground-state matrix elements and\nthe fact that all excited states and contact terms are Euclidean-time\ndependent. We demonstrate the utility of our method with a calculation of the\nnucleon axial charge using gradient-flowed domain-wall valence quarks on the\n$N_f=2+1+1$ MILC highly improved staggered quark ensemble with lattice spacing\nand pion mass of approximately 0.15 fm and 310 MeV respectively. We show full\ncontrol over excited-state systematics with the new method and obtain a value\nof $g_A = 1.213(26)$ with a quark-mass-dependent renormalization coefficient.",
        "positive": "Confinement Physics in Quantum Chromodynamics: We study the confinement physics in QCD in the maximally abelian (MA) gauge\nusing the SU(2) lattice QCD, based on the dual-superconductor picture. In the\nMA gauge, off-diagonal gluon components are forced to be small, and the\noff-diagonal angle variable $\\chi_\\mu(s)$ tends to be random. Within the\nrandom-variable approximation for $\\chi_\\mu(s)$, we analytically prove the\nperimeter law of the off-diagonal gluon contribution to the Wilson loop in the\nMA gauge, which leads to abelian dominance on the string tension. To clarify\nthe origin of abelian dominance for the long-range physics, we study the\ncharged-gluon propagator in the MA gauge using the lattice QCD, and find that\nthe effective mass $m_{ch} \\simeq 0.9 {\\rm GeV}$ of the charged gluon is\ninduced by the MA gauge fixing. In the MA gauge, there appears the macroscopic\nnetwork of the monopole world-line covering the whole system, which would be\nidentified as monopole condensation at a large scale. To prove monopole\ncondensation in the field-theoretical manner, we derive the inter-monopole\npotential from the dual Wilson loop in the monopole part of QCD, which carries\nthe nonperturbative QCD aspects, in the MA gauge. The dual gluon mass is\nevaluated as $m_B \\simeq $0.5GeV in the monopole part in the infrared region,\nwhich is the evidence of the dual Higgs mechanism by monopole condensation."
    },
    {
        "anchor": "QCD hadron spectrum with domain wall fermions: We present the QCD hadron spectrum for the cases of both quenched and\ntwo-flavor dynamical domain wall fermions. We compare the results obtained\nusing the Wilson gauge action and a renormalization group improved gauge\naction. Finite volume effects and the dependence on the finite extent of the\nfifth dimension are discussed.",
        "positive": "Soft Covariant Gauges on the Lattice: We present an exploratory study of a one-parameter family of covariant,\nnon-perturbative lattice gauge-fixing conditions, that can be implemented\nthrough a simple Monte Carlo algorithm. We demonstrate that at the numerical\nlevel the procedure is feasible, and as a first application we examine the\ngauge dependence of the gluon propagator."
    },
    {
        "anchor": "How the Quark Number fluctuates in QCD at small chemical potential: We discuss the distribution of the quark number over the gauge fields for QCD\nat nonzero quark chemical potential. As the quark number operator is\nnon-hermitian, the distribution is over the complex plane. Moreover, because of\nthe fermion determinant, the distribution is not real and positive. The\ncomputation is carried out within leading order chiral perturbation theory and\ngives direct insight into the delicate cancellations that take place in\ncontributions to the total baryon number.",
        "positive": "Strings on the lattice and AdS/CFT: We present a new auxiliary field representation for the four-fermi term of\nthe gauge-fixed Green-Schwarz superstring action which describes fluctuations\naround the null-cusp background in $AdS_5\\times S^5$. We sketch the main\nfeatures of the fermionic operator spectrum, identifying the region of\nparameter space where the sign ambiguity is absent. Measurements for the\nobservables in the setup here described are presented and discussed in a\nforthcoming publication."
    },
    {
        "anchor": "High-energy hadron-hadron (dipole-dipole) scattering on the lattice: We will discuss how the problem of high-energy hadron-hadron (dipole-dipole)\nscattering at low momentum transfer can be approached from the point of view of\nlattice QCD, by means of Monte Carlo numerical simulations.",
        "positive": "Color superconductivity on the lattice -- analytic predictions from QCD\n  in a small box: We investigate color superconductivity on the lattice using the gap equation\nfor the Cooper pair condensate. The weak coupling analysis is justified by\nchoosing the physical size of the lattice to be smaller than the QCD scale,\nwhile keeping the aspect ratio of the lattice small enough to suppress thermal\nexcitations. In the vicinity of the critical coupling constant that separates\nthe superconducting phase and the normal phase, the gap equation can be\nlinearized, and by solving the corresponding eigenvalue problem, we obtain the\ncritical point and the Cooper pair condensate without assuming its explicit\nform. The momentum components of the condensate suggest spatially isotropic\ns-wave superconductivity with Cooper pairs formed by quarks near the Fermi\nsurface. The chiral symmetry in the massless limit is spontaneously broken by\nthe Cooper pair condensate, which turns out to be dominated by the scalar and\nthe pseudo-scalar components. Our results provide useful predictions, in\nparticular, for future lattice simulations based on methods to overcome the\nsign problem such as the complex Langevin method."
    },
    {
        "anchor": "A Perturbative Study of a General Class of Lattice Dirac Operators: A perturbative study of a general class of lattice Dirac operators is\nreported, which is based on an algebraic realization of the Ginsparg-Wilson\nrelation in the form\n  $\\gamma_{5}(\\gamma_{5}D)+(\\gamma_{5}D)\\gamma_{5} =\n  2a^{2k+1}(\\gamma_{5}D)^{2k+2}$ where $k$ stands for a non-negative integer.\nThe choice $k=0$ corresponds to the commonly discussed Ginsparg-Wilson relation\nand thus to the overlap operator. We study one-loop fermion contributions to\nthe self-energy of the gauge field, which are related to the fermion\ncontributions to the one-loop $\\beta$ function and to the Weyl anomaly. We\nfirst explicitly demonstrate that the Ward identity is satisfied by the\nself-energy tensor. By performing careful analyses, we then obtain the correct\nself-energy tensor free of infra-red divergences, as a general consideration of\nthe Weyl anomaly indicates. This demonstrates that our general operators give\ncorrect chiral and Weyl anomalies. In general, however, the Wilsonian effective\naction, which is supposed to be free of infra-red complications, is expected to\nbe essential in the analyses of our general class of Dirac operators for\ndynamical gauge field.",
        "positive": "Two-flavor staggered-fermion thermodynamics at $N_t = 12$: We present new results in an ongoing study of the nature of the high\ntemperature crossover in QCD with two light fermion flavors. These results are\nobtained with the conventional staggered fermion action at the smallest lattice\nspacing to date---approximately 0.1 fm. Of particular interest are a study of\nthe temperature of the crossover, an important indicator of continuum scaling,\na determination of the induced baryon charge and baryon susceptibility, used to\nstudy the dissolution of hadrons at the crossover, the scalar susceptibility, a\nsignal for the appearance of soft modes, and the chiral order parameter, used\nto test models of critical behavior."
    },
    {
        "anchor": "First results from dynamical chirally improved fermions: We simulate Quantum Chromodynamics in four Euclidean dimensions with two\n(degenerate mass) flavors of dynamical quarks. The Dirac operator is the\nso-called chirally improved operator that has been studied so far in quenched\ncalculations. We now present results of an implementation with the Hybrid Monte\nCarlo (HMC) algorithm including stout smearing. Our results are from an 8^3x16\nlattice with tadpole improved Luescher-Weisz gauge action. We present our\nestimate of the lattice spacing, the pi and rho meson masses and evidence for\ntunneling between different topological sectors.",
        "positive": "Recent Developments in Quark Nuclear Physics: We provide an overview of recent work exploring the quark-mass dependence of\nhadronic observables and the associated role of chiral nonanalytic behavior due\nto the meson-cloud of hadrons. In particular, we address an issue of great\ncurrent interest, namely the degree of model independence of results obtained\nthrough a controlled extrapolation of lattice QCD simulation results. Physical\ninsights gained from this research are highlighted. We emphasize how chiral\neffective field theory formulated with a finite-range regulator provides a\nreliable and model-independent extrapolation to the physical world."
    },
    {
        "anchor": "Gap Domain Wall Fermions: I demonstrate that the chiral properties of Domain Wall Fermions (DWF) in the\nlarge to intermediate lattice spacing regime of QCD, 1 to 2 GeV, are\nsignificantly improved by adding to the action two standard Wilson fermions\nwith supercritical mass equal to the negative DWF five dimensional mass. Using\nquenched DWF simulations I show that the eigenvalue spectrum of the transfer\nmatrix Hamiltonian develops a substantial gap and that the residual mass\ndecreases appreciatively. Furthermore, I confirm that topology changing remains\nactive and that the hadron spectrum of the added Wilson fermions is above the\nlattice cutoff and therefore is irrelevant. I argue that this result should\nalso hold for dynamical DWF and furthermore that it should improve the chiral\nproperties of related fermion methods.",
        "positive": "$N\u03c0$ scattering in the Roper channel: We present results from our recent lattice QCD study of $N\\pi$ scattering in\nthe positive-parity nucleon channel, where the puzzling Roper resonance\n$N^*(1440)$ resides in experiment. Using a variety of hadron operators, that\ninclude $qqq$-like, $N\\pi$ in $p$-wave and $N\\sigma$ in $s$-wave, we\nsystematically extract the excited lattice spectrum in the nucleon channel up\nto 1.65 GeV. Our lattice results indicate that N$\\pi$ scattering in the elastic\napproximation alone does not describe a low-lying Roper. Coupled channel\neffects between $N\\pi$ and $N\\pi\\pi$ seem to be crucial to render a low-lying\nRoper in experiment, reinforcing the notion that this state could be a\ndynamically generated resonance. After giving a brief motivation for studying\nthe Roper channel and the relevant technical details to this study, we will\ndiscuss the results and the conclusions based on our lattice investigation and\nin comparison with other lattice calculations."
    },
    {
        "anchor": "A lattice determination of g_A and <x> from overlap fermions: We present results for the nucleon's axial charge g_A and the first moment\n<x> of the unpolarized parton distribution function from a simulation of\nquenched overlap fermions.",
        "positive": "Local CP-violation and electric charge separation by magnetic fields\n  from lattice QCD: We study local CP-violation on the lattice by measuring the local correlation\nbetween the topological charge density and the electric dipole moment of\nquarks, induced by a constant external magnetic field. This correlator is found\nto increase linearly with the external field, with the coefficient of\nproportionality depending only weakly on temperature. Results are obtained on\nlattices with various spacings, and are extrapolated to the continuum limit\nafter the renormalization of the observables is carried out. This\nrenormalization utilizes the gradient flow for the quark and gluon fields. Our\nfindings suggest that the strength of local CP-violation in QCD with physical\nquark masses is about an order of magnitude smaller than a model prediction\nbased on nearly massless quarks in domains of constant gluon backgrounds with\ntopological charge. We also show numerical evidence that the observed local\nCP-violation correlates with spatially extended electric dipole structures in\nthe QCD vacuum."
    },
    {
        "anchor": "Complete Monopole Dominance of the Yang-Mills Confining Potential: We continue our investigation of quark confinement using a particular variant\nof the Cho-Duan-Ge gauge independent Abelian decomposition. The decomposition\nsplits the gauge field into a restricted Abelian part and a coloured part in a\nway that preserves gauge covariance. The restricted part of the gauge field can\nbe divided into a Maxwell term and a topological term. Previously, we showed\nthat by a particular choice of this decomposition we could fully describe the\nconfining potential using only the restricted gauge field. We proposed that\nvarious topological objects (a form of magnetic monopole) could arise in the\nrestricted field which would drive confinement. Our mechanism does not\nexplicitly refer to a dual Meissner effect, nor does it use centre vortices. We\ndid not need to gauge fix or introduce any new dynamical fields.\n  We show that if we do gauge fix as well as performing the Abelian\ndecomposition then it is possible to ensure that the topological part of the\nrestricted field fully accounts for the confining potential. Our relationship\nis exact: there is no approximation or model involved. This isolates the\nobjects responsible for confinement from non-confining contributions to the\ngauge field, allowing a direct search for our proposed topological objects.\nUsing numerical studies in SU(2), we confirm that our proposed monopoles are\npresent in the field, and the winding number associated with these monopoles is\na key factor driving quark confinement.\n  In SU(2), our monopoles are described by two parameters. We show that it is\npossible to re-parametrise the Yang Mills action and the functional integration\nmeasure in terms of these variables (plus the necessary additional parameters).\nWe can thus treat the monopoles as dynamical variables in the functional\nintegral. This might be the first step in a future analytical computation to\ncomplement our numerical results.",
        "positive": "Optimizing the domain wall fermion Dirac operator using the R-Stream\n  source-to-source compiler: The application of the Dirac operator on a spinor field, the Dslash\noperation, is the most computation-intensive part of the lattice QCD\nsimulations. It is often the key kernel to optimize to achieve maximum\nperformance on various platforms. Here we report on a project to optimize the\ndomain wall fermion Dirac operator in Columbia Physics System (CPS) using the\nR-Stream source-to-source compiler. Our initial target platform is the Intel PC\nclusters. We discuss the optimization strategies involved before and after the\nautomatic code generation with R-Stream and present some preliminary benchmark\nresults."
    },
    {
        "anchor": "Locations of Roberge-Weiss transition endpoints in lattice QCD with\n  $N_f=2$ improved KS quarks: Result on the locations of the tricritical points of $N_f=2$ lattice QCD with\nimaginary chemical potential is presented. Simulations are carried out with\nSymanzik improved gauge action and Asqtad fermion action. With imaginary\nchemical potential $i\\mu_I=i\\pi T$, previous studies show that the\nRoberge-Weiss (RW) transition endpoints are triple points at both large and\nsmall quark masses, and second order transition points at intermediate quark\nmasses. The triple and second order endpoints are separated by two tricritical\nones. Our simulations are carried out at 7 values of quark mass $am$ ranging\nfrom 0.024 to 0.070 on lattice volume $12^3\\times 4, 16^3\\times 4,\\,\n20^3\\times4$. The susceptibility and Binder cumulant of the imaginary part of\nPolyakov loop are employed to determine the nature of RW transition endpoints.\nThe simulations suggest that the two tricritical points are within the range\n$0.024-0.026$ and $0.040-0.050$, respectively.",
        "positive": "Improved staggered quark actions with reduced flavour symmetry\n  violations for lattice QCD: We introduce a new class of actions for staggered quarks in lattice QCD which\nsignificantly reduce flavour symmetry violations in the pion mass spectrum. An\naction introduced by the MILC collaboration for the same purpose is seen to be\na special case. We discus how such actions arise from a systematic attempt to\nreduce flavour symmetry violations in the weak coupling limit. It is shown that\nfor quenched lattice QCD at 6/g^2=5.7, representative actions of this class\ngive a considerable reduction in flavour symmetry violation over the standard\nstaggered action, and a significant reduction over what is achieved by the MILC\naction."
    },
    {
        "anchor": "NNLO unquenched calculation of the b quark mass: By combining the first unquenched lattice computation of the B-meson binding\nenergy with the recently calculated two-loop contribution to the lattice HQET\nmass, we determine the $\\bar{MS}$ b-quark mass, $\\bar{m}_{b}(\\bar{m}_{b})$ at\nthe NNLO. We find $\\bar{m}_{b}(\\bar{m}_{b}) = (4.26\\pm 0.03 \\pm 0.04 \\pm 0.05)\n{\\rm GeV}$. The inclusion of the two-loop effects is one of the steps necessary\nto extract $\\bar{m}_{b}(\\bar{m}_{b})$ with a precision better than ${\\cal\nO}(\\Lambda_{QCD})$, which is the uncertainty due to the presence of an IR\nrenormalon singularity in the perturbative series of the residual mass. Our\nresults have been obtained on a sample of 60 lattices of size $24^{3}\\times 40$\nat $\\beta=5.6$, using the unquenched Wilson action with two degenerate sea\nquarks. The quark propagators have been computed using the unquenched links\ngenerated by the T$\\chi$L Collaboration.",
        "positive": "Beta-function, Renormalons and the Mass Term from Perturbative Wilson\n  Loops: Several Wilson loops on several lattice sizes are computed in Perturbation\nTheory via a stochastic method. Applications include: Renormalons, the Mass\nTerm in Heavy Quark Effective Theory and (possibly) the beta-function."
    },
    {
        "anchor": "Correlations and Critical Behavior in Lattice Gluodynamics: In the Landau-gauge lattice gluodynamics we find that, both in the SU(2) and\nSU(3) theory, a correlation of the Polyakov loop with the asymmetry of the\n$A^2$ gluon condensate as well as with the longitudinal propagator makes it\npossible to determine the critical behavior of these quantities. We discuss\nfinite-volume corrections and reveal that they can be reduced by the use of\nregression analysis. We also analyze the temperature dependence of low-momenta\npropagators in different Polyakov-loop sectors.",
        "positive": "Rho decay width from the lattice: While the masses of light hadrons have been extensively studied in lattice\nQCD simulations, there exist only a few exploratory calculations of the strong\ndecay widths of hadronic resonances. We will present preliminary results of a\ncomputation of the rho meson width obtained using $N_f=2+1$ flavor simulations.\nThe work is based on L\\\"uscher's formalism and its extension to moving frames."
    },
    {
        "anchor": "Scaling test of two-flavor O(a)-improved lattice QCD: We report on a scaling test of several mesonic observables in the\nnon-perturbatively O(a) improved Wilson theory with two flavors of dynamical\nquarks. The observables are constructed in a fixed volume of 2.4fm x (1.8fm)^3\nwith Schroedinger functional boundary conditions. No significant scaling\nviolations are found. Using the kaon mass determined in \\cite{cernI}, we update\nour estimate of the Lambda parameter to Lambda^(2)_{msbar}/m_K = 0.52(6).",
        "positive": "Aspects of chiral symmetry in QCD at T = 128 MeV: We investigate several aspects of chiral symmetry in QCD at a temperature of\n$T = 128\\,\\text{MeV}$. The study is based on a $24\\times 96^3$ lattice-QCD\nensemble with O($a$)-improved Wilson quarks and physical up, down and strange\nquark masses. The pion quasiparticle turns out to be significantly lighter than\nthe zero-temperature pion mass, even though the corresponding static\ncorrelation length is shorter. We perform a quantitative comparison of our\nfindings to predictions of chiral perturbation theory. Among several order\nparameters for chiral symmetry restoration, we compute the difference of the\nvector- and axial-vector time-dependent correlators and find it to be reduced\nby a factor $\\sim2/3$ as compared to its vacuum counterpart."
    },
    {
        "anchor": "Effective Theories of Confinement: We review some approaches to describe confinement in terms of effective\n(model) field theories. After a brief discussion of the dual Abelian Higgs\nmodel, we concentrate on a lattice analysis of the Faddeev-Niemi effective\naction conjectured to describe the low-lying excitations of SU(2) gluodynamics.\nWe generalize the effective action such that it contains all operators built\nfrom a unit color vector field n with O(3) symmetry and maximally four\nderivatives. To avoid the presence of Goldstone bosons, we include explicit\nsymmetry breaking terms parametrized by an external field h of mass-dimension\ntwo. We find a mass gap of the order of 1.5 GeV.",
        "positive": "QCD thermodynamics with nonzero chemical potential at $N_t=6$ and\n  effects from heavy quarks: We extend our work on QCD thermodynamics with 2+1 quark flavors at nonzero\nchemical potential to finer lattices with $N_t=6$. We study the equation of\nstate and other thermodynamic quantities, such as quark number densities and\nsusceptibilities, and compare them with our previous results at $N_t=4$. We\nalso calculate the effects of the addition of the charm and bottom quarks on\nthe equation of state at zero and nonzero chemical potential. These effects are\nimportant for cosmological studies of the early Universe."
    },
    {
        "anchor": "A formulation of domain-wall fermions in the Schr\u00f6dinger functional: We present a formulation of domain-wall fermions in the Schr\\\"odinger\nfunctional by following a universality argument. To examine the formulation, we\nnumerically investigate the spectrum of the free operator and perform a\none-loop analysis to confirm universality and renormalizability. We also study\nthe breaking of the Ginsparg-Wilson relation to understand the structure of\nchiral symmetry breaking from two sources: The bulk and boundary. Furthermore,\nwe discuss the lattice artifacts of the step scaling function by comparing with\nother fermion discretizations.",
        "positive": "A Fitting Robot for Variational Analysis: We develop a robot algorithm to maximise the number of distinct states\nreliably extracted from correlator data using the variational analysis method.\nThe robot explores the variational parameter space and attempts to remove, as\nfar as possible, the human element from the fitting of the subsequent\northogonalised data."
    },
    {
        "anchor": "The Abelian Higgs Model in Three Dimensions with Improved Action: We study the Abelian Higgs Model using an improved form of the action in the\nscalar sector. The subleading corrections are carefully analysed and the\nconnection between lattice and continuous parameters is worked out. The\nsimulation shows a remarkable improvement of the numerical performance.",
        "positive": "Dual representation of lattice QCD with worldlines and worldsheets of\n  abelian color fluxes: We present a new dual representation for lattice QCD in terms of wordlines\nand worldsheets. The exact reformulation is carried out using the recently\ndeveloped abelian color flux method where the action is decomposed into\ncommuting minimal terms that connect different colors on neighboring sites.\nExpanding the Boltzmann factors for these commuting terms allows one to\nreorganize the gauge field contributions according to links such that the gauge\nfields can be integrated out in closed form. The emerging constraints give the\ndual variables the structure of worldlines for the fermions and worldsheets for\nthe gauge degrees of freedom. The partition sum has the form of a strong\ncoupling expansion and with the abelian color flux approach discussed here all\ncoefficients of the expansion are known in closed form. We present the dual\nform for three cases: pure SU(3) lattice gauge theory, strong coupling QCD and\nfull QCD, and discuss in detail the constraints for the color fluxes and their\nphysical interpretation."
    },
    {
        "anchor": "Color confinement and dual superconductivity of the vacuum. IV: A scaling analysis is made of the order parameter describing monopole\ncondensation at the deconfining transition of N_f=2 QCD around the chiral\npoint. In accordance with scaling properties of the specific heat, studied in a\nprevious paper, scaling is consistent with a first order transition. The status\nof dual superconductivity of the vacuum as a mechanism of color confinement is\nreviewed.",
        "positive": "SU(3) Gauge Theory with Adjoint Fermions: We analyze the finite temperature phase diagram of QCD with fermions in the\nadjoint representation. The simulations performed with four dynamical Majorana\nfermions, which is equivalent to two Dirac fermions, show that the\ndeconfinement and chiral phase transitions occur at two distinct temperatures,\n$T_{\\rm chiral} \\simeq 6.65 T_{\\rm deconf}$. While the deconfinement transition\nis first order we find evidence for a continuous chiral transition. We also\npresent potentials for $T<T_{\\rm deconf}$ and $T_{\\rm deconf}<T< T_{\\rm\nchiral}$ both for fundamental and adjoint fermion-antifermion pairs."
    },
    {
        "anchor": "Baryon-Baryon Interactions in the Flavor SU(3) Limit from Full QCD\n  Simulations on the Lattice: We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD\nsimulations with degenerate quark masses for all flavors. The BB potentials in\nthe orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions\nmeasured on the lattice. We observe strong flavor-spin dependences of the BB\npotentials at short distances. In particular, a strong repulsive core exists in\nthe flavor-octet and spin-singlet channel (the 8_s representation), while an\nattractive core appears in the flavor singlet channel (the 1 representation).\nWe discuss a relation of such flavor-spin dependence with the Pauli exclusion\nprinciple in the quark level. Possible existence of an H-dibaryon resonance\nabove the Lambda-Lambda threshold is also discussed.",
        "positive": "Deflation Methods in Fermion Inverters: I will review recent developments in matrix deflation methods, by Ronald\nMorgan/Walter Wilcox, Andreas Stathopoulos/Konstantinos Orginos, and Martin\nL\\\"uscher, with application to lattice QCD fermion inversion. I will begin with\na short review of deflation-related work in the field. The Morgan/Wilcox\nalgorithms using GMRES and BiCGStab for deflation will be described. Typical\nresults for quenched (Wilson and twisted mass) and dynamical configurations\n(CP-PACS and ETMC) will be displayed and discussed. I will outline how\ninclusion of multiple right-hand sides and multiple shifts can be accommodated\nwithin versions of these methods. I will also review deflation methods based on\nConjugate Gradient introduced by Stathopoulos and Orginos for hermitian systems\nwith multiple right-hand sides as well as L\\\"uscher's non-hermitian domain\ndecomposition algorithm using Generalized Conjugate Residual.}"
    },
    {
        "anchor": "Chiral behaviour of the pion decay constant in $N_f=2$ QCD: As increased statistics and new ensembles with light pions have become\navailable within the CLS effort, we complete previous work by inspecting the\nchiral behaviour of the pion decay constant. We discuss the validity of Chiral\nPerturbation Theory ($\\chi$PT) and examine the results concerning the pion\ndecay constant and the ensuing scale setting, the pion mass squared in units of\nthe quark mass, and the ratio of decay constants $f_K/f_\\pi$; along the way,\nthe relevant low-energy constants of SU(2) $\\chi$PT are estimated. All\nsimulations were performed with two dynamical flavours of nonperturbatively\nO(a)-improved Wilson fermions, on volumes with $m_\\pi L \\geq 4$, pion masses\n$\\geq$ 192 MeV and lattice spacings down to 0.048 fm. Our error analysis takes\ninto account the effect of slow modes on the autocorrelations.",
        "positive": "RI/MOM and RI/SMOM renormalization of overlap quark bilinears on domain\n  wall fermion configurations: Renormalization constants (RCs) of overlap quark bilinear operators on\n2+1-flavor domain wall fermion configurations are calculated by using the\nRI/MOM and RI/SMOM schemes. The scale independent RC for the axial vector\ncurrent is computed by using a Ward identity. Then the RCs for the quark field\nand the vector, tensor, scalar and pseudoscalar operators are calculated in\nboth the RI/MOM and RI/SMOM schemes. The RCs are converted to the\n$\\overline{\\rm MS}$ scheme and we compare the numerical results from using the\ntwo intermediate schemes. The lattice size is $48^3\\times96$ and the inverse\nspacing $1/a = 1.730(4) {\\rm~GeV}$."
    },
    {
        "anchor": "$m_c/m_s$ with Brillouin fermions: We present a calculation of the ratio of the charm quark mass to the strange\nquark mass. Using the Brillouin improved Wilson action, we are able to\ncalculate this ratio in a single framework, using a relativistic fermionic\naction throughout. The calculation is carried out on selected ensembles of two\nflavor clover improved lattices produced by the QCDSF collaboration, allowing\nan extrapolation to the continuum, to infinite volume and to the physical pion\nmass.",
        "positive": "Lattice calculation of the pion transition form factor with $N_f=2+1$\n  Wilson quarks: We present a lattice QCD calculation of the double-virtual neutral pion\ntransition form factor, with the goal to cover the kinematic range relevant to\nhadronic light-by-light scattering in the muon $g-2$. Several improvements have\nbeen made compared to our previous work. First, we take into account the\neffects of the strange quark by using the $N_f=2+1$ CLS gauge ensembles.\nSecondly, we have implemented the on-shell $\\mathcal{O}(a)$-improvement of the\nvector current to reduce the discretization effects associated with Wilson\nquarks. Finally, in order to have access to a wider range of photon\nvirtualities, we have computed the transition form factor in a moving frame as\nwell as in the pion rest-frame. After extrapolating the form factor to the\ncontinuum and to physical quark masses, we compare our results with\nphenomenology. We extract the normalization of the form factor with a precision\nof 3.5\\% and confirm within our uncertainty previous somewhat conflicting\nestimates for a low-energy constant that appears in chiral perturbation theory\nfor the decay $\\pi^0 \\to \\gamma\\gamma$ at NLO. With additional input from\nexperiment and theory, we reproduce recent estimates for the decay width\n$\\Gamma(\\pi^0 \\to \\gamma\\gamma)$. We also study the asymptotic large-$Q^2$\nbehavior of the transition form factor in the double-virtual case. Finally, we\nprovide as our main result a more precise model-independent lattice estimate of\nthe pion-pole contribution to hadronic light-by-light scattering in the muon\n$g-2$: $a_{\\mu}^{\\mathrm{HLbL}; \\pi^0} = (59.7 \\pm 3.6) \\times 10^{-11}$. Using\nin addition the normalization of the form factor obtained by the PrimEx\nexperiment, we get the lattice and data-driven estimate\n$a_{\\mu}^{\\mathrm{HLbL}; \\pi^0} = (62.3 \\pm 2.3) \\times 10^{-11}$."
    },
    {
        "anchor": "A lattice calculation of the branching ratio for $\\overline{B}\n  \\rightarrow K^* \u03b3$: Preliminary results are presented on the calculation of the relevant form\nfactor for the radiative decay $\\overline{B} \\rightarrow K^* \\gamma$ We find\nthat the form factor is weakly dependent on the spectator quark mass. We\ncompare the results obtained for a full chiral extrapolation and where this\nindependence is assumed. Both results are found to be statistically consistent\nwith the experimental data.",
        "positive": "Green Function Simulation of Hamiltonian Lattice Models with Stochastic\n  Reconfiguration: We apply a recently proposed Green Function Monte Carlo to the study of\nHamiltonian lattice gauge theories. This class of algorithms computes quantum\nvacuum expectation values by averaging over a set of suitable weighted random\nwalkers. By means of a procedure called Stochastic Reconfiguration the long\nstanding problem of keeping fixed the walker population without a priori\nknowledge on the ground state is completely solved. In the $U(1)_2$ model,\nwhich we choose as our theoretical laboratory, we evaluate the mean plaquette\nand the vacuum energy per plaquette. We find good agreement with previous works\nusing model dependent guiding functions for the random walkers."
    },
    {
        "anchor": "Gauge Problem of Monopole Dynamics in SU(2) Lattice Gauge Theory: Gauge problem of monopole dynamics is studied in SU(2) lattice gauge theory.\nWe study first abelian and monopole contributions to the static potential in\nfour smooth gauges, i.e., Laplacian Abelian (LA), Maximally Abelian Wilson Loop\n(MAWL) and L-type gauges in comparison with Maximally Abelian (MA) gauge. They\nall reproduce the string tension in good agreement with the SU(2) string\ntension. MA gauge is not the only choice of the good gauge which is suitable\nfor the color confinement mechanism. Using an inverse Monte-Carlo method and\nthe blockspin transformation, we determine effective monopole actions and the\nrenormalization group (RG) flows of its coupling constants in various abelian\nprojection schemes. Every RG flow looks to converge to a unique curve which\nsuggests gauge independence in the infrared region.",
        "positive": "The temperature dependence of the chiral condensate in the Schwinger\n  model with Matrix Product States: We present our recent results for the tensor network (TN) approach to lattice\ngauge theories. TN methods provide an efficient approximation for quantum\nmany-body states. We employ TN for one dimensional systems, Matrix Product\nStates, to investigate the 1-flavour Schwinger model. In this study, we compute\nthe chiral condensate at finite temperature. From the continuum extrapolation,\nwe obtain the chiral condensate in the high temperature region consistent with\nthe analytical calculation by Sachs and Wipf."
    },
    {
        "anchor": "Hadronic coupling constants of $g_{\u03c3\u03c0\u03c0}$ in lattice QCD: We investigate the coupling constant $g_{\\sigma\\pi\\pi}$ for the hadronic\ndecay $\\sigma\\to\\pi\\pi$ only using the relevant three-point function, which is\nevaluated by the moving-wall source technique with a pretty good\nnoise-to-signal ratio. This simulation is carried out on a $40^3\\times96$ MILC\ngauge configuration with $N_f=2+1$ flavor of the \"Asqtad\" improved staggered\ndynamical sea quarks at the lattice spacing $a \\approx 0.09$ fm. Our estimated\nvalue for this given MILC fine lattice gauge ensemble\n$g_{\\sigma\\pi\\pi}=2.71(42)$ GeV.",
        "positive": "Chiral limit of 2-color QCD at strong couplings: We study two-color lattice QCD with massless staggered fermions in the strong\ncoupling limit using a new and efficient cluster algorithm. We focus on the\nphase diagram of the model as a function of temperature $T$ and baryon chemical\npotential $\\mu$ by working on $L_t \\times L^d$ lattices in both $d=2,3$. In\n$d=3$ we find that at $\\mu=0$ the ground state of the system breaks the global\nU(2) symmetry present in the model to U(1), while the finite temperature phase\ntransition (with $L_t=4$) which restores the symmetry is a weak first order\ntransition. In $d=2$ we find evidence for a novel phase transition similar to\nthe Berezinky-Kosterlitz-Thouless phenomena. On the other hand the quantum\n(T=0) phase transition to a symmetric phase as a function of $\\mu$ is second\norder in both $d=2,3$ and belongs to the mean field universality class."
    },
    {
        "anchor": "Lattice simulations of adjoint QCD with one Dirac overlap fermion: In this work we investigate the infrared behaviour of a Yang-Mills theory\ncoupled to a massless fermion in the adjoint representation of the gauge group\nSU(2). This model has many interesting properties, corresponding to the\n$\\mathcal{N}=2$ Super-Yang-Mills theory without scalars and in the recent years\nthere has been an increasing interest toward understanding whether confinement\nand fermion condensation occur at low energy. We simulate the theory on the\nlattice close to the massless limit using the overlap discretization of the\nfermion action, allowing a precise and clean study of the chiral symmetry\nbreaking pattern and of the fermion condensate. We present results for the\nscale setting, the condensate and the running of the coupling constant through\nthe gradient flow -- all of them pointing to a theory without an infrared fixed\npoint and remaining confined deep in the infrared regime.",
        "positive": "Generalized L\u00fcscher Formula in Multi-channel Baryon-Meson Scattering: L\\\"uscher's formula relates the elastic scattering phase shifts to the\ntwo-particle energy levels in a finite cubic box. The original formula was\nobtained for elastic scattering of two massive spinless particles in the center\nof mass frame. In this paper, we consider the case for the scattering of a spin\n1/2 particle with a spinless particle in multi-channel scattering. A\ngeneralized relation between the energy of two particle system and the\nscattering matrix elements is established. We first obtain this relation using\nquantum-mechanics in both center-of-mass frame and in a general moving frame.\nThe result is then generalized to quantum field theory using methods outlined\nin Ref. \\cite{Hansen:2012tf}. We verify that the results obtained using both\nmethods are equivalent up to terms that are exponentially suppressed in the box\nsize."
    },
    {
        "anchor": "Scaling behavior of the overlap quark propagator in Landau gauge: The properties of the momentum space quark propagator in Landau gauge are\nexamined for the overlap quark action in quenched lattice QCD. Numerical\ncalculations are done on three lattices with different lattice spacings and\nsimilar physical volumes to explore the approach of the quark propagator toward\nthe continuum limit. We have calculated the nonperturbative momentum-dependent\nwave function renormalization function Z(p) and the nonperturbative mass\nfunction M(p) for a variety of bare quark masses and perform an extrapolation\nto the chiral limit. We find the behavior of Z(p) and M(p) are in reasonable\nagreement between the two finer lattices in the chiral limit, however the data\nsuggest that an even finer lattice is desirable. The large momentum behavior is\nexamined to determine the quark condensate.",
        "positive": "Renormalisation and off-shell improvement in lattice perturbation theory: We discuss the improvement of flavour non-singlet point and one-link lattice\nquark operators, which describe the quark currents and the first moment of the\nDIS structure functions respectively. Suitable bases of improved operators are\ngiven, and the corresponding renormalisation factors and improvement\ncoefficients are calculated in one-loop lattice perturbation theory, using the\nSheikholeslami-Wohlert (clover) action. To this order we achieve off-shell\nimprovement by eliminating the effect of contact terms. We use massive\nfermions, and our calculations are done keeping all terms up to first order in\nthe lattice spacing, for arbitrary m^2/p^2, in a general covariant gauge. We\nalso compare clover fermions with fermions satisfying the Ginsparg-Wilson\nrelation, and show how to remove O(a) effects off-shell in this case too, and\nhow this is in many aspects simpler than for clover fermions. Finally, tadpole\nimprovement is also considered."
    },
    {
        "anchor": "Lattice QFT with FermiQCD: FermiQCD is a C++ library for fast development of parallel Lattice Quantum\nField Theory computations. It has been developed following a top-down fully\nObject Oriented design approach with focus on simplicity of use. FermiQCD\nincludes: a heatbath algorithm for Wilson and $O(a^2)$ improved SU(n) gauge\nactions; inversion algorithms for Wilson, Clover, Kogut-Susskind, Asqtad, and\nDomain Wall fermionic actions; example programs for various types of meson\npropagators; and converters for the most common gauge file formats.",
        "positive": "Poisson to Random Matrix Transition in the QCD Dirac Spectrum: At zero temperature the lowest part of the spectrum of the QCD Dirac operator\nis known to consist of delocalized modes that are described by random matrix\nstatistics. In the present paper we show that the nature of these eigenmodes\nchanges drastically when the system is driven through the finite temperature\ncross-over. The lowest Dirac modes that are delocalized at low temperature\nbecome localized on the scale of the inverse temperature. At the same time the\nspectral statistics changes from random matrix to Poisson statistics. We\ndemonstrate this with lattice QCD simulations using 2+1 flavors of light\ndynamical quarks with physical masses. Drawing an analogy with Anderson\ntransitions we also examine the mobility edge separating localized and\ndelocalized modes in the spectrum. We show that it scales in the continuum\nlimit and increases sharply with the temperature."
    },
    {
        "anchor": "Status Report on ILDG activities: A status report about the International Lattice Data Grid (ILDG) is given.\nDifferent countries participating in the ILDG have created regional lattice\ndata grid solutions that are implemented, working and used. The remaining task\nand the focus of present activities is the development of the interoperability\nof these regional grids. A first, successful step in this direction is a\nmetadata catalogue service which is already working interoperable.",
        "positive": "Importance of meson-meson and of diquark-antidiquark creation operators\n  for a $\\bar{b} \\bar{b} u d$ tetraquark: In recent years, the existence of a hadronically stable $\\bar{b} \\bar{b} u d$\ntetraquark with quantum numbers $I(J^P) = 0(1^+)$ was confirmed by first\nprinciples lattice QCD computations. In this work we use lattice QCD to compare\ntwo frequently discussed competing structures for this tetraquark by\nconsidering meson-meson as well as diquark-antidiquark creation operators. We\nuse the static-light approximation, where the two $\\bar{b}$ quarks are assumed\nto be infinitely heavy with frozen positions, while the light $u$ and $d$\nquarks are fully relativistic. By minimizing effective energies and by solving\ngeneralized eigenvalue problems we determine the importance of the meson-meson\nand the diquark-antidiquark creation operators with respect to the ground\nstate. It turns out, that the diquark-antidiquark structure dominates for\n$\\bar{b} \\bar{b}$ separations $r < 0.25 \\, \\text{fm}$, whereas it becomes\nincreasingly more irrelevant for larger separations, where the $I(J^P) =\n0(1^+)$ tetraquark is mostly a meson-meson state. We also estimate the\nmeson-meson to diquark-antidiquark ratio of this tetraquark and find around\n$60\\% / 40\\%$."
    },
    {
        "anchor": "Charmed semileptonics with twisted-mass valence quarks: Our charm program uses a mixed action with twisted-mass valence quarks over\nnon-perturbatively improved Wilson sea quarks, in order to study various\nquantities in a relativistic and manifestly local framework of full QCD. The\nsea sector consists of $N_\\mathrm{f}=2+1$ ensembles generated by the CLS\ninitiative. Taking advantage of open boundary conditions, this allows access to\nfine ensembles without topological freezing. Here we focus in particular on our\ncurrent progress on $D\\to K\\nu l$ and $D\\to \\pi\\nu l$ semileptonics. Those are\nfirst and foremost useful for the computation of the CKM matrix elements\n$|V_{cs}|$ and $|V_{cd}|$. We show that all discretisation effects seem to be\nreasonably under control with this choice of action, in particular those\nrelated to hypercubic lattice artefacts. Eventually, we obtain preliminary\nresults of the form factors as a very smooth curve on the whole range of\nmomentum transfer, and in particular the signal at zero $q^2$ appears to have\nthe potential to be competitive with earlier published results.",
        "positive": "Massive fermions without fermion bilinear condensates: We study a lattice field theory model containing two flavors of massless\nstaggered fermions with an onsite four-fermion interaction. The model contains\na $SU(4)$ symmetry which forbids non-zero fermion bilinear mass terms, due to\nwhich there is a massless fermion phase at weak couplings. However, even at\nstrong couplings fermion bilinear condensates do not appear in our model,\nalthough fermions do become massive. While the existence of this exotic\nstrongly coupled massive fermion phase was established long ago, the nature of\nthe transition between the massless and the massive phase has remained unclear.\nUsing Monte Carlo calculations in three space-time dimensions, we find evidence\nfor a direct second order transition between the two phases suggesting that the\nexotic lattice phase may have a continuum limit at least in three dimensions. A\nsimilar exotic second order critical point was found recently in a bilayer\nsystem on a honeycomb lattice."
    },
    {
        "anchor": "Modified Lattice Landau Gauge: We propose a modified lattice Landau gauge based on stereographically\nprojecting the link variables on the circle S^1 -> R for compact U(1) or the\n3-sphere S^3 -> R^3 for SU(2) before imposing the Landau gauge condition. This\ncan reduce the number of Gribov copies exponentially and solves the Gribov\nproblem in compact U(1) where it is a lattice artifact. Applied to the maximal\nAbelian subgroup this might be just enough to avoid the perfect cancellation\namongst the Gribov copies in a lattice BRST formulation for SU(N), and thus to\navoid the Neuberger 0/0 problem. The continuum limit of the Landau gauge\nremains unchanged.",
        "positive": "Lattice QCD Evidence for Exotic Tetraquark Resonance: We study the manifestly exotic tetraquark D$_{\\rm s0}^{++}(cu\\bar s \\bar d)$\nand the scalar tetraquark $f_0(ud \\bar u \\bar d)$ in SU(3)$_c$ anisotropic\nquenched lattice QCD with the $O(a)$-improved Wilson (clover) fermion with\nvarious quark masses including the idealized SU(4)$_f$ case. For $f_0(ud\\bar u\n\\bar d)$ etc., we only consider connected diagrams at the quenched level, i.e.,\nthe tetraquark $f_0(ud\\bar u\\bar d)$ is identical with D$_{\\rm s0}^{++} (cu\\bar\ns \\bar d)$ in the idealized SU(4)$_f$ case. First, for comparison, we study the\nlowest $q\\bar q$ scalar meson, and find that it has a large mass of about\n1.37GeV after chiral extrapolation, which corresponds to $f_0(1370)$. Second,\nwe investigate the lowest 4Q state in the spatial periodic boundary condition,\nand find that it is just a scattering state of two pseudoscalar mesons, as is\nexpected. Third, to extract spatially-localized 4Q resonances, we use the\nHybrid Boundary Condition (HBC) method, where anti-periodic and periodic\nboundary conditions are imposed on quarks ($c$,$u$) and antiquarks ($\\bar\ns$,$\\bar d$), respectively. By applying the HBC on a finite-volume lattice, the\nthreshold of the two-meson scattering state is raised up, while the mass of a\ncompact 4Q resonance is almost unchanged. In HBC, we find a nontrivial 4Q\nresonance state about 100 MeV below the two-meson threshold in some quark-mass\nregion. Its chiral behavior largely differs from a two-meson scattering state.\nThe scalar tetraquark $f_0(ud\\bar u\\bar d)$ is found to have the mass of about\n1.1GeV after chiral extrapolation, and seems to correspond to $f_0(980)$. Then,\nthe manifestly exotic tetraquark D$_{\\rm s0}^{++}(cu\\bar s \\bar d)$ would exist\naround 1GeV in the idealized SU(4)$_f$ chiral limit. Finally, MEM analysis is\napplied to obtain the spectral function of the 4Q system."
    },
    {
        "anchor": "Determination of the Collins-Soper Kernel from Lattice QCD: We present lattice results for the non-perturbative Collins-Soper (CS)\nkernel, which describes the energy-dependence of transverse momentum-dependent\nparton distributions (TMDs). The CS kernel is extracted from the ratios of\nfirst Mellin moments of quasi-TMDs evaluated at different nucleon momenta.The\nanalysis is done with dynamical $N_f=2+1$ clover fermions for the CLS ensemble\nH101 ($a=0.0854\\,\\mathrm{fm}$, $m_{\\pi}=m_K=422\\,\\mathrm{MeV}$). The computed\nCS kernel is in good agreement with experimental extractions and previous\nlattice studies.",
        "positive": "On the continuum limit of Landau gauge gluon and ghost propagators in\n  SU(2) lattice gauge gluodynamics: We continue the systematic computation of Landau gauge gluon and ghost\npropagators of SU(2) gluodynamics using a sequence of increasing lattice sizes\nL^4 up to L=112 with corresponding \\beta-values chosen to keep the linear\nphysical size a(\\beta)L ~ 9.6 fm fixed. To extremize the Landau gauge\nfunctional we employ simulated annealing combined with subsequent\noverrelaxation. Renormalizing the propagators at momentum \\mu= 2.2 GeV we\nobserve quite strong lattice artifacts for the gluon propagator as well as for\nthe ghost dressing function within the momentum region q < 1.0 GeV. The\ndependence on the lattice spacing for the gluon propagator at lowest accessible\nphysical momentum values does not yet allow a simple extrapolation to the\ncontinuum limit. On the contrary, the running coupling derived from the bare\ndressing functions seems less affected by lattice artifacts."
    },
    {
        "anchor": "Staggered chiral random matrix theory: We present a random matrix theory (RMT) for the staggered lattice QCD Dirac\noperator. The staggered RMT is equivalent to the zero-momentum limit of the\nstaggered chiral Lagrangian and includes all taste breaking terms at their\nleading order. This is an extension of previous work which only included some\nof the taste breaking terms. We will also present some results for the taste\nbreaking contributions to the partition function and the Dirac eigenvalues.",
        "positive": "On the effective string spectrum of the tridimensional Z(2) gauge model: We study the Z(2) lattice gauge theory in three dimensions, and present high\nprecision estimates for the first few energy levels of the string spectrum.\nThese results are obtained from new numerical data for the two-point Polyakov\nloop correlation function, which is measured in the 3d Ising spin system using\nduality. This allows us to perform a stringent comparison with the predictions\nof effective string models. We find a remarkable agreement between the\nnumerical estimates and the Nambu-Goto predictions for the energy gaps at\nintermediate and large distances. The precision of our data allows to\ndistinguish clearly between the predictions of the full Nambu-Goto action and\nthe simple free string model up to an interquark distance $r \\approx\n10/\\sqrt{\\sigma}$. At the same time, our results also confirm the breakdown of\nthe effective picture at short distances, supporting the hypothesis that terms\nwhich are not taken into account in the usual Nambu-Goto string formulation\nyield a non-trivial shift to the energy levels. Furthermore, we discuss the\ntheoretical implications of these results."
    },
    {
        "anchor": "Lambda-bar, lambda_1 and m_b in three-flavor (lattice) QCD: The heavy-quark expansion for inclusive semi-leptonic B decays introduces\n$\\bar{\\Lambda}$ and $\\lambda_1$, which are matrix elements in heavy-quark\neffective field theory. We review how they can be obtained from an analysis of\nthe heavy quark mass dependence of heavy-light meson masses in lattice QCD. We\npresent preliminary results for the bottom quark mass, $m_b$, using\n$\\bar{\\Lambda}$ and $\\lambda_1$ for the $B_s$ meson from a 2+1 sea-flavor\nunquenched calculation.",
        "positive": "$d^\\ast (2380)$ dibaryon from lattice QCD: The $\\Delta\\Delta$ dibaryon resonance $d^\\ast (2380)$ with $(J^P, I)=(3^+,\n0)$ is studied theoretically on the basis of the 3-flavor lattice QCD\nsimulation with heavy pion masses ($m_\\pi =679, 841$ and $1018$ MeV). By using\nthe HAL QCD method, the central $\\Delta$-$\\Delta$ potential in the ${}^7S_3$\nchannel is obtained from the lattice data with the lattice spacing $a\\simeq\n0.121$ fm and the lattice size $L\\simeq 3.87$ fm. The resultant potential shows\na strong short-range attraction, so that a quasi-bound state corresponding to\n$d^\\ast (2380)$ is formed with the binding energy $25$-$40$ MeV below the\n$\\Delta\\Delta$ threshold for the heavy pion masses. The tensor part of the\ntransition potential from $\\Delta\\Delta$ to $NN$ is also extracted to\ninvestigate the coupling strength between the $S$-wave $\\Delta\\Delta$ system\nwith $J^P=3^+$ and the $D$-wave $NN$ system. Although the transition potential\nis strong at short distances, the decay width of $d^\\ast (2380)$ to $NN$ in the\n$D$-wave is kinematically suppressed, which justifies our single-channel\nanalysis at the range of the pion mass explored in this study."
    },
    {
        "anchor": "Improving Polynomial-filtered Hybrid Monte Carlo With Hasenbusch: The predominant method for generating Lattice QCD configurations is Hybrid\nMonte Carlo (HMC). In order to speed up this generation, a wide range of\npreconditioning techniques that modify the lattice action have been devised.\nThis work compares the performance of the well-known Hasenbusch preconditioning\ntechnique with the polynomial filtering technique on a small $16^3 \\times 32$\nlattice with two flavours of Wilson fermions at a pion mass $M_{\\pi} \\sim\n400~\\mathrm{MeV}$. We explore a novel method of combining polynomial and\nHasenbusch filters, revealing a speedup when compared to the standard two\nHasenbusch filters. This comes with the added advantage of simplified tuning.",
        "positive": "Evidence for non-analytic light quark mass dependence in the baryon\n  spectrum: Using precise lattice QCD computations of the baryon spectrum, we present the\nfirst direct evidence for the presence of contributions to the baryon masses\nwhich are non-analytic in the light quark masses; contributions which are often\ndenoted \"chiral logarithms\". We isolate the poor convergence of SU(3) baryon\nchiral perturbation theory to the flavor-singlet mass combination. The\nflavor-octet baryon mass splittings, which are corrected by chiral logarithms\nat next to leading order in SU(3) chiral perturbation theory, yield baryon-pion\naxial coupling constants D, F, C and H consistent with QCD values; the first\nevidence of chiral logarithms in the baryon spectrum. The Gell-Mann--Okubo\nrelation, a flavor-27 baryon mass splitting, which is dominated by chiral\ncorrections from light quark masses, provides further evidence for the presence\nof non-analytic light quark mass dependence in the baryon spectrum; we\nsimultaneously find the GMO relation to be inconsistent with the first few\nterms in a taylor expansion in m_s - m_l, which must be valid for small values\nof this SU(3) breaking parameter. Additional, more definitive tests of SU(3)\nchiral perturbation theory will become possible with future, more precise,\nlattice calculations."
    },
    {
        "anchor": "Hard hadron spectroscopy: I review lattice QCD calculations that compute the masses of the flavour\nsinglet pseudoscalar mesons. I describe the progress in computing the mass\nspectrum of light 0++ mesons using lattice QCD. I also compare the results for\nbasic quantities such as fpi and mrho, from various different formalisms of\nlattice QCD. I discuss the physical value of r0.",
        "positive": "Chiral dynamics in the low-temperature phase of QCD: We investigate the low-temperature phase of QCD and the crossover region with\ntwo light flavors of quarks. The chiral expansion around the point $(T, m_q =\n0)$ in the temperature vs. quark-mass plane indicates that a sharp real-time\nexcitation exists with the quantum numbers of the pion. We determine its\ndispersion relation and test the applicability of the chiral expansion. The\ntime-dependent correlators are also analyzed using the Maximum Entropy Method\n(MEM), yielding consistent results. Finally, we test the predictions of\nordinary chiral perturbation theory around the point $(T = 0, m_q = 0)$ for the\ntemperature dependence of static observables. Around the crossover temperature,\nwe find that all quantities considered depend only mildly on the quark mass in\nthe considered range 8MeV $\\leq \\bar{m}^{\\bar{\\text{MS}}} \\leq$ 15MeV."
    },
    {
        "anchor": "Spectroscopy of hadrons with heavy quarks from lattice QCD: Lattice QCD results on hadrons with heavy quarks are briefly reviewed. The\nfocus is on the spectrum of conventional and exotic hadrons. Structure of\ncertain conventional hadrons is addressed as well.",
        "positive": "Running coupling for Wilson bermions: A non perturbative finite size scaling technique is used to study a running\ncoupling in lattice Yang-Mills theory coupled to a bosonic Wilson spinor field\nin the Schr\\\"odinger functional scheme. This corresponds to two negative\nflavours. The scaling behaviour in this case is compared to quenched results\nand to QCD with two flavours. The continuum limit is confronted with\nrenormalized perturbation theory."
    },
    {
        "anchor": "Weak matrix elements for CP violation: We present preliminary results of matrix elements of four-fermion operators\nrelevant to the determination of e and e'/e using staggered fermions.",
        "positive": "Matrix formulation of superspace on 1D lattice with two supercharges: Following the approach developed by some of the authors in recent papers and\nusing a matrix representation for the superfields, we formulate an exact\nsupersymmetric theory with two supercharges on a one dimensional lattice. In\nthe superfield formalism supersymmetry transformations are uniquely defined and\ndo not suffer of the ambiguities recently pointed out by some authors. The\naction can be written in a unique way and it is invariant under all\nsupercharges. A modified Leibniz rule applies when supercharges act on a\nsuperfield product and the corresponding Ward identities take a modified form\nbut hold exactly at least at the tree level, while their validity in presence\nof radiative corrections is still an open problem and is not considered here."
    },
    {
        "anchor": "A lattice approach to QCD in the chiral regime: Non-perturbative lattice studies of QCD in the chiral thermodynamic regime,\nwhere chiral symmetry is spontaneously broken, require to deal with almost\nquark zero modes in a theoretically clean and computationally efficient way. We\ndiscuss the basic features and some realistic tests of a formulation, known as\nlattice tmQCD, that fulfills these requirements. Based on a talk given by R.\nFrezzotti at the conference HEP2001 (Budapest, July 2001)",
        "positive": "Dressed Wilson loops as dual condensates in response to magnetic and\n  electric fields: We introduce dressed Wilson loops as a novel confinement observable. It\nconsists of closed planar loops of arbitrary geometry but fixed area, and its\nexpectation values decay with the latter. The construction of dressed Wilson\nloops is based on chiral condensates in response to magnetic and electric\nfields, thus linking different physical concepts. We present results for\ngeneralized condensates and dressed Wilson loops on dynamical lattice\nconfigurations and confirm the agreement with conventional Wilson loops in the\nlimit of large probe mass. We comment on the renormalization of dressed Wilson\nloops."
    },
    {
        "anchor": "Gauge-independent transition separating confinement-Higgs phase in the\n  lattice SU(2) gauge-fundamental scalar model: According to the preceding studies, the lattice SU(2) gauge-scalar model with\na single scalar field in the fundamental representation of the gauge group has\na single confinement-Higgs phase where Confinement and Higgs regions are\nsubregions of an analytically continued single phase and there are no\nthermodynamic phase transitions, which is a well-known consequence of the\nOsterwalder-Seiler-Fradkin-Shenker theorem. In this paper, we show that we can\ndefine new types of gauge-invariant operators by combining the original\nfundamental scalar field and the so-called color-direction field which is\nobtained by change of field variables based on the gauge-covariant\ndecomposition of the gauge field due to Cho-Duan-Ge-Shabanov and Faddeev-Niemi.\nBy performing the numerical simulations on the lattice without any gauge\nfixing, we reproduce the conventional thermodynamic transition line in the weak\ngauge coupling, and moreover we find a new transition line detected by the new\ngauge-invariant operators which separates the confinement-Higgs phase into two\nparts, confinement phase and the Higgs phase, in the strong gauge coupling. All\nresults are obtained in the gauge-independent way, since no gauge fixing has\nbeen imposed in the numerical simulations. Moreover, we discuss a physical\ninterpretation for the new transition from the viewpoint of the realization of\na global symmetry.",
        "positive": "The B and B_s Meson Decay Constants from Lattice QCD: We present a new determination of the B and B_s meson decay constants using\nNRQCD b-quarks, HISQ light and strange valence quarks and the MILC\ncollaboration N_f=2+1 lattices. The new calculations improve on HPQCD's earlier\nwork with NRQCD b-quarks by replacing AsqTad with HISQ valence quarks, by\nincluding a more chiral MILC fine ensemble in the analysis, and by employing\nbetter tuned quark masses and overall scale. We find f_B = 0.191(9)GeV, f_{B_s}\n= 0.228(10)GeV and f_{B_s}/f_B = 1.188(18). Combining the new value for\nf_{B_s}/f_B with a recent very precise determination of the B_s meson decay\nconstant based on HISQ b-quarks, f_{B_s} = 0.225(4)GeV, leads to f_B =\n0.189(4)GeV. With errors of just 2.1% this represents the most precise f_B\navailable today."
    },
    {
        "anchor": "Partial Wave Mixing in Hamiltonian Effective Field Theory: We explore partial-wave mixing in the finite volume based on HEFT, and\nprovide the P-Matrix to show the degree of partial-wave mixing. An example of\nisospin-2 $\\pi\\pi$ scattering is used to check the consistency between HEFT and\nL\\\"{u}scher's method.",
        "positive": "Light meson decay constants beyond the quenched approximation: We calculate the effects of including dynamical fermion loops in the lattice\nQCD estimates of meson decay constants, by extrapolating the results from\nnegative flavour numbers after a suitable matching of the pion and rho mass.\nFor moderately light quarks, the values of the decay constants not corrected\nfor the renormalization constants increase with respect to their quenched\nvalues."
    },
    {
        "anchor": "The QCD equation of state and the effects of the charm: We present an update on the QCD equation of state of the Wuppertal-Budapest\nCollaboration, extending our previous studies [JHEP 0601 (2006) 089, JHEP 1011\n(2010) 077]. A Symanzik improved gauge and a stout-link improved staggered\nfermion action is utilized. We discuss partial quenching and present\npreliminary results for the fully dynamical charmed equation of state.",
        "positive": "Critical Behavior of the Schwinger Model with Wilson Fermions: We present a detailed analysis, in the framework of the MFA approach, of the\ncritical behaviour of the lattice Schwinger model with Wilson fermions on\nlattices up to $24^2$, through the study of the Lee-Yang zeros and the specific\nheat. We find compelling evidence for a critical line ending at $\\kappa = 0.25$\nat large $\\beta$. Finite size scaling analysis on lattices $8^2,12^2,16^2,\n20^2$ and $24^2$ indicates a continuous transition. The hyperscaling relation\nis verified in the explored $\\beta$ region."
    },
    {
        "anchor": "Renormalized Polyakov loops in various representations in finite\n  temperature SU(2) gauge theory: We present results for the renormalized Polyakov loop in the three lowest\nirreducible representations of SU(2) gauge theory at finite temperature. We\nwill discuss their scaling behavior near $T_c$ and test Casimir scaling in the\ndeconfined phase. Moreover, we will compare these results to calculations for\nthe renormalized Polyakov loops in several representations in the SU(3) gauge\ntheory.",
        "positive": "Noncompact Lattice Formulation of Gauge Theories: We expand the gauge field in terms of a suitably constructed complete set of\nBloch wave functions, each labeled by a band designation $\\,n\\,$ and a wave\nnumber $\\,\\vec K\\,$ restricted to the Brillouin zone. A noncompact formulation\nof lattice QCD (or QED) can be derived by restricting the expansion only to the\n$\\,0^{th}$-band ($\\,n = 0\\,$) functions, which are simple continuum\ninterpolations of discrete values associated with sites or links on a lattice.\nThe exact continuum theory can be reached through the inclusion of all $\\,n =\n0\\,$ and $\\,n \\ne 0\\,$ bands, without requiring the lattice size $\\,\\ell \\to\n0\\,$. This makes it possible, at a nonzero $\\,\\ell\\,$, for the lattice coupling\n$\\,g_\\ell\\,$ to act as the renormalized continuum coupling. All physical\nresults in the continuum are, of course, independent of $\\,\\ell\\,$."
    },
    {
        "anchor": "Chiral Symmetry, Quark Mass, and Scaling of the Overlap Fermions: The chiral symmetry relation and scaling of the overlap fermions are studied\nnumerically on the quenched lattices at 3 couplings with about the same\nphysical volume. We find that the generalized Gell-Mann-Oakes-Renner relation\nis satisfied to better than 1% down to the smallest quark mass at $m_0a =\n0.006$. We also obtain the quark mass from the PCAC relation and the\npseudoscalar masses. The renormalization group invariant quark mass is shown to\nbe fairly independent of scale. The $\\pi$ and $\\rho$ masses at a fixed\n$m_{\\pi}/m_{\\rho}$ ratio indicate small $O(a^2)$ corrections. It is found that\nthe critical slowing down sets in abruptly at a very small quark mass close to\nthose of the physical u and d quarks.",
        "positive": "The topological susceptibility and pion decay constant from lattice QCD: We study the topological susceptibility, chi, in two flavour lattice QCD. We\nfind clear evidence for the expected suppression of chi at small quark mass.\nThe estimate of the pion decay constant, f_pi = 105 +/-5 +18/-10 MeV, is\nconsistent with the experimental value of approximately 93 MeV. We compare chi\nto the large-N_c prediction and find consistency over a large range of quark\nmasses."
    },
    {
        "anchor": "Sea quark effects in B_K from N_f=2 clover-improved Wilson fermions: We report calculations of the parameter B_K appearing in the Delta S=2\nneutral kaon mixing matrix element, whose uncertainty limits the power of\nunitarity triangle constraints for testing the standard model or looking for\nnew physics. We use two flavours of dynamical clover-improved Wilson lattice\nfermions and look for dependence on the dynamical quark mass at fixed lattice\nspacing. We see some evidence for dynamical quark effects and in particular B_K\ndecreases as the sea quark masses are reduced towards the up/down quark mass.",
        "positive": "Center Vortex Model for SU(3) Yang-Mills Theory: The center vortex model for the infrared sector of SU(3) Yang-Mills theory is\nreviewed. After discussing the physical foundations underlying the model, some\ntechnical aspects of its realisation are discussed. The confining properties of\nthe model are presented in some detail and compared to known results from full\nlattice Yang-Mills theory. Particular emphasis is put on the new phenomenon of\nvortex branching, which is instrumental in establishing first order behaviour\nof the SU(3) phase transition. Finally, the vortex free energy is verified to\nfurnish an order parameter for the deconfinement phase transition. It is shown\nto exhibit a weak discontinuity at the critical temperature, in agreement with\npredictions from lattice gauge theory."
    },
    {
        "anchor": "Instantons and chiral symmetry breaking in SU(N) gauge theories: We address the question of whether the low modes of the Dirac operator are\ncaused by topological objects such as instantons in SU(N) gauge theories. We\nstudy the pseudo-scalar density of these modes, finding the size distributions\nof the instantons, and comparing it with the underlying gauge field. We find\nthat, although the near-zero modes of the Dirac operator depend on topology for\nall N, their small instanton content decreases as N increases.",
        "positive": "Effects of the charm quark on the QCD equation of state: We study the effects of the addition of the charm quark on the QCD equation\nof state at zero and nonzero chemical potential on lattices with $N_t=6$. Our\nensembles are quenched with respect to charm and the charm quark is a valence\nstaggered quark. Along the trajectory of constant physics the ratio $m_s/m_c$\nis kept constant after tuning the charm quark mass at a lattice spacing of\nabout 0.09 fm. We find that the charm quark has a significant contribution to\nthe equation of state at zero chemical potential already at temperatures\nbetween about $1.2T_c$ and $2T_c$. The additional contribution at nonzero\nchemical potential vanishes within the current statistical uncertainty."
    },
    {
        "anchor": "The QCD equation of state and transition at finite temperature: We present the latest results for the equation of state and the crossover\ntransition in 2+1 flavor QCD from the HotQCD Collaboration. Bulk thermodynamic\nquantities - energy density, pressure, entropy density, and the speed of sound\n- are calculated on lattices with temporal extent $N_t = 8$ in the temperature\nrange 140 < T < 540 MeV. We utilize two improved staggered fermion actions,\nasqtad and p4, with the mass for the two degenerate light quarks chosen to be\n$m_{ud} = 0.1 m_s$, corresponding to $m_\\pi \\approx 220$ MeV for the lightest\npion. We also calculate observables that are sensitive to the chiral and\ndeconfing transitions - the light and strange quark number susceptibilities,\nthe chiral condensate, and the renormalized Polyakov loop - finding that\ndeconfinement and chiral symmetry restoration occur in the same narrow\ntemperature interval.",
        "positive": "Characterization of phases and boundary effects in U(1) gauge theory: We show that the two phases of the 4-dimensional compact U(1) lattice gauge\ntheory are characterized by the existence or absence of an infinite current\nnetwork, defining ``infinite'' on a finite lattice in a manner appropriate to\nthe chosen boundary conditions. In addition for open and fixed boundary\nconditions we demonstrate the effects of inhomogeneities and provide examples\nof the reappearance of an energy gap."
    },
    {
        "anchor": "Light composite scalar in eight-flavor QCD on the lattice: We present the first observation of a flavor-singlet scalar meson as light as\nthe pion in $N_f=8$ QCD on the lattice, using the Highly Improved Staggered\nQuark action. Such a light scalar meson can be regarded as a composite Higgs\nwith mass 125 GeV. In accord with our previous lattice results showing that the\ntheory exhibits walking behavior, the light scalar may be a technidilaton, a\npseudo Nambu-Goldstone boson of the approximate scale symmetry in walking\ntechnicolor.",
        "positive": "Towards the N_f=2 deconfinement transition temperature with O(a)\n  improved Wilson fermions: An update: We give an update on our current project to determine the transition\ntemperature and the order of the deconfinement transition in the chiral limit\nof two flavour QCD. We use nonperturbatively O(a) improved Wilson fermions of\nthe Sheikholeslami-Wohlert type, employing the efficient deflation accelerated\nDDHMC algorithm. We start at lattices with N_t>=12 and pion masses below 600\nMeV, aiming at chiral and continuum limits with light quarks."
    },
    {
        "anchor": "Universality of phase diagrams in QCD and QCD-like theories: We show the universality of phase diagrams in QCD and QCD-like theories\nthrough the large-N_c equivalence. The whole phase diagrams are identical\nbetween QCD at finite isospin chemical potential and SO(2N_c) and Sp(2N_c)\ngauge theories at finite baryon chemical potential. In the chiral limit, they\nare also identical to that of QCD at finite chiral chemical potential. Outside\nthe pion or diquark condensed phase in these theories, the universality of\nphase diagrams is applicable to QCD at finite baryon chemical potential. We\nfurther argue that the universality may work approximately even for N_c=3. Our\nresult makes it possible to study QCD at finite baryon chemical potential and\nhigh temperature, especially the chiral phase transition, using sign-free\ntheories on the lattice.",
        "positive": "Perturbative Wilson loops with massive sea quarks on the lattice: We present O(g^4) calculations of both planar and non-planar Wilson loops for\nvarious actions in the presence of sea quarks. In particular, the plaquette,\nthe static potential and the static self energy are calculated to this order\nfor massive Wilson, Sheikholeslami-Wohlert and Kogut-Susskind fermions,\nincluding the mass and n_f dependence. The results can be used to obtain\nalpha_{MS} and m_b(m_b) from lattice simulations. We compare our perturbative\ncalculations to simulation data of the static potential and report excellent\nqualitative agreement with boosted perturbation theory predictions for\ndistances r<1/GeV. We are also able to resolve differences in the running of\nthe coupling between n_f=2 and n_f=0 static potentials. We compute perturbative\nestimates of the ``beta-shifts'' of QCD with sea quarks, relative to the\nquenched theory, which we find to agree within 10 % with non-perturbative\nsimulations. This is done by matching the respective static potentials at large\ndistances. The prospects of determining the QCD running coupling from low\nenergy hadron phenomenology in the near future are assessed. We obtain the\nresult $\\Lambda^{(2)}_{\\bar{MS}}r_0=0.69(15)$ for the two flavour QCD\nLambda-parameter from presently available lattice data where $r_0^{-1}\\approx\n400$ MeV and estimate $\\alpha_{\\bar{MS}}^{(5)}(m_Z)=0.1133(59)$."
    },
    {
        "anchor": "$K \\to \u03c0\u03c0$ Decays in a Finite Volume: We discuss finite-volume computations of two-body hadronic decays below the\ninelastic threshold (e.g. $K\\to\\pi\\pi$ decays). The relation between\nfinite-volume matrix elements and physical amplitudes, recently derived by\nLellouch and L\\\"uscher, is extended to all elastic states under the inelastic\nthreshold. We present a detailed comparison of our approach with that of\nLellouch and L\\\"uscher and discuss the possible limitations of the method which\ncould arise due to the presence of inelastic thresholds. We also examine a\nstandard alternative method which can be used to extract the real part of the\ndecay amplitude from correlators of the form $< 0 |T[\\pi\\pi{\\cal H}_WK ]| 0 >$.\nWe show that in this case there are finite-volume corrections which vanish as\ninverse powers of the volume, which cannot be removed by a multiplicative\nfactor.",
        "positive": "Monopole Condensation and Polyakov Loop in Finite-Temperature Pure QCD: We study the relation between the abelian monopole condensation and the\ndeconfinement phase transition of the finite-temperature pure QCD. The\nexpectation value of the monopole contribution to the Polyakov loop becomes\nzero when a long monopole loop is distributed uniformly in the configuration of\nthe confinement phase. On the other hand, it becomes non-zero when the long\nmonopole loop disappears in the deconfinement phase. We also discuss the\nrelation between the monopole behaviors and the usual interpretation of the\nspontaneous breaking of Z(N) symmetry in finite-temperature SU(N) QCD. It is\nfound that the boundary condition of the space direction is important to\nunderstand the Z(N) symmetry in terms of the monopoles."
    },
    {
        "anchor": "A study of the quenched bc mass spectrum at beta=6.2: We present an analysis of the mass spectrum of heavy quarkonia with\nnon-degenerate quark masses. The heavier (bottom) valence quark is treated in a\nnon-relativistic fashion and the other (charm) is a relativistic Wilson-like\nquark using the improved SW action. Such states provide and interesting probe\nbetween the relativistic B meson states and the non-relativistic bottomonium\nstates.",
        "positive": "Nature of finite temperature and density phase transitions in\n  many-flavor QCD: We investigate the phase structure of (2+Nf)-flavor QCD, where two light\nflavors and Nf massive flavors exist, to discuss the feasibility of the\nelectroweak baryogenesis in realistic technicolor scenario and to understand\nproperties of finite density QCD. Because an appearance of a first order phase\ntransition at finite temperature is a necessary condition for the baryogenesis,\nit is important to study the nature of finite temperature phase transition.\nApplying the reweighting method, the probability distribution function of the\nplaquette is calculated in the many-flavor QCD. Through the shape of the\ndistribution function, we determine the critical mass of heavy flavors\nterminating the first order region, and find it to become larger with Nf. We\nmoreover study the critical line at finite density and the first order region\nis found to become wider as increasing the chemical potential. We discuss how\nthe properties of real (2+1)-flavor QCD at finite temperature and density can\nbe extracted from simulations of many-flavor QCD."
    },
    {
        "anchor": "Masses of $D$ mesons, $D_s$ mesons and charmonium states from twisted\n  mass lattice QCD: We compute masses of $D$ mesons, $D_s$ mesons and charmonium states using\nWilson twisted mass lattice QCD. We present results for spin $J = 0,1,2,3$,\nparity $\\mathcal{P} = -,+$ and in case of charmonium also charge conjugation\n$\\mathcal{C} = -,+$. Computations are based on quark-antiquark creation\noperators and performed at three different unphysically heavy $u/d$ quark\nmasses allowing an extrapolation to the physical $u/d$ quark mass. Within\ncombined statistical and systematic errors, which are around $2 \\% \\ldots 3\n\\%$, our results agree with available experimental results. Particular focus is\nput on the $J^\\mathcal{P} = 1^+$ mesons $D_1(2430)$ and $D_1(2420)$. We\nseparate and classify these close-by states according to the total angular\nmomentum of their light degrees of freedom, $j \\approx 1/2$ and $j \\approx\n3/2$. This is a first important step to study decays $B^{(\\ast)} \\rightarrow\nD_1 + l + \\nu$, for which a long-standing conflict between theory and\nexperiment exists.",
        "positive": "Dirac-mode expansion analysis for Polyakov loop: To clarify the relation between chiral symmetry breaking and color\nconfinement, we investigate the Polyakov loop in terms of the Dirac eigenmodes\nin SU(3) lattice QCD. We analyze the low-lying (IR) and UV Dirac-mode\ncontribution to the Polyakov loop, respectively, using the Dirac-mode expansion\nmethod. In the confined phase, the Polyakov loop $< L_P >$ remains almost zero\nand $Z_3$ center symmetry is thus unbroken, even after removing low-lying\nDirac-modes, which are responsible to chiral symmetry breaking. In the confined\nphase, the Polyakov loop $< L_P >$ also remains almost zero by UV Dirac-modes\ncut. In addition to the confined phase, we analyze the Polyakov loop in the\ndeconfined phase and its temperature dependence. The behavior of the Polyakov\nloop $< L_P >$ is found to be almost unchanged by the cut of low-lying or UV\nDirac-modes in both confined and deconfined phases."
    },
    {
        "anchor": "Phase with no mass gap in non-perturbatively gauge-fixed Yang--Mills\n  theory: An equivariantly gauge-fixed non-abelian gauge theory is a theory in which a\ncoset of the gauge group, not containing the maximal abelian subgroup, is gauge\nfixed. Such theories are non-perturbatively well-defined. In a finite volume,\nthe equivariant BRST symmetry guarantees that expectation values of\ngauge-invariant operators are equal to their values in the unfixed theory.\nHowever, turning on a small breaking of this symmetry, and turning it off after\nthe thermodynamic limit has been taken, can in principle reveal new phases. In\nthis paper we use a combination of strong-coupling and mean-field techniques to\nstudy an SU(2) Yang--Mills theory equivariantly gauge fixed to a U(1) subgroup.\nWe find evidence for the existence of a new phase in which two of the gluons\nbecomes massive while the third one stays massless, resembling the broken phase\nof an SU(2) theory with an adjoint Higgs field. The difference is that here\nthis phase occurs in an asymptotically-free theory.",
        "positive": "Emergent strongly coupled ultraviolet fixed point in four dimensions\n  with 8 K\u00e4hler-Dirac fermions: The existence of a strongly coupled ultraviolet fixed point in 4-dimensional\nlattice models as they cross into the conformal window has long been\nhypothesized. The SU(3) gauge system with 8 fundamental fermions is a good\ncandidate to study this phenomenon as it is expected to be very close to the\nopening of the conformal window. I study the system using staggered lattice\nfermions in the chiral limit. My numerical simulations employ improved lattice\nactions that include heavy Pauli-Villars (PV) type bosons. This modification\ndoes not affect the infrared dynamics but greatly reduces the ultraviolet\nfluctuations, thus allowing the study of stronger renormalized couplings than\npreviously possible. I consider two different PV actions and find that both\nshow an apparent continuous phase transition in the 8-flavor system.\n  I investigate the critical behavior using finite size scaling of the\nrenormalized gradient flow coupling. The finite size scaling curve-collapse\nanalysis predicts a first order phase transition consistent with discontinuity\nexponent $\\nu=1/4$ in the system without PV bosons. The scaling analysis with\nthe PV boson actions is not consistent with a first order phase transition. The\nnumerical data are well described by \"walking scaling\" corresponding to a\nrenormalization group $\\beta$ function that just touches zero, $\\beta(g^2) \\sim\n(g^2 - g^2_\\star)^2$, though second order scaling cannot be excluded. Walking\nscaling could imply that the 8-flavor system is the opening of the conformal\nwindow, an exciting possibility that could be related to t'Hooft anomaly\ncancellation of the system."
    },
    {
        "anchor": "Lefschetz thimbles and stochastic quantisation: Complex actions in the\n  complex plane: Lattice field theories with a complex action can be studied numerically by\nallowing a complexified configuration space to be explored. Here we compare the\nrecently introduced formulation on a Lefschetz thimble with the result from\nstochastic quantisation (or complex Langevin dynamics) in the case of a simple\nmodel and contrast the distributions being sampled. We also study the role of\nthe residual phase on the Lefschetz thimble.",
        "positive": "A percent-level determination of the nucleon axial coupling from Quantum\n  Chromodynamics: The $\\textit{axial coupling of the nucleon}$, $g_A$, is the strength of its\ncoupling to the $\\textit{weak}$ axial current of the Standard Model of particle\nphysics, in much the same way as the electric charge is the strength of the\ncoupling to the electromagnetic current. This axial coupling dictates the rate\nat which neutrons decay to protons, the strength of the attractive long-range\nforce between nucleons and other features of nuclear physics. Precision tests\nof the Standard Model in nuclear environments require a quantitative\nunderstanding of nuclear physics rooted in Quantum Chromodynamics, a pillar of\nthe Standard Model. The prominence of $g_A$ makes it a benchmark quantity to\ndetermine theoretically - a difficult task because quantum chromodynamics is\nnon-perturbative, precluding known analytical methods. Lattice Quantum\nChromodynamics provides a rigorous, non-perturbative definition of quantum\nchromodynamics that can be implemented numerically. It has been estimated that\na precision of two percent would be possible by 2020 if two challenges are\novercome: contamination of $g_A$ from excited states must be controlled in the\ncalculations and statistical precision must be improved markedly. Here we\nreport a calculation of $g_A^{QCD} = 1.271\\pm0.013$, using an unconventional\nmethod inspired by the Feynman-Hellmann theorem that overcomes these\nchallenges."
    },
    {
        "anchor": "Light Quark Masses and the CP violation parameter $\u03b5'/\u03b5$: We present estimates of light quarks masses using lattice data. Our main\nresults are based on a global analysis of all the published data for Wilson and\nStaggered fermions, both in the quenched approximation and with $n_f=2$\ndynamical flavors. The Wilson and Staggered results agree after extrapolation\nto the continuum limit for both the $n_f=0,2$ theories. Our best estimates, in\nthe MSbar scheme at scale $2 GeV$, are $mbar=3.2(4) MeV$ and $m_s = 90(20) MeV$\nin the quenched approximation, and $mbar ~ 2.7 MeV$ and $m_s ~ 70 MeV$ for the\n$n_f=2$ theory. These estimates are significantly smaller than phenomenological\nestimates based on sum rules, but maintain the ratios predicted by chiral\nperturbation theory. Along with the new estimates of 4-fermion operators, lower\nquark masses have a significant impact on the extraction of\n$\\epsilon'/\\epsilon$ from the Standard Model.",
        "positive": "Deflation acceleration of lattice QCD simulations: Close to the chiral limit, many calculations in numerical lattice QCD can\npotentially be accelerated using low-mode deflation techniques. In this paper\nit is shown that the recently introduced domain-decomposed deflation subspaces\ncan be propagated along the field trajectories generated by the Hybrid Monte\nCarlo (HMC) algorithm with a modest effort. The quark forces that drive the\nsimulation may then be computed using a deflation-accelerated solver for the\nlattice Dirac equation. As a consequence, the computer time required for the\nsimulations is significantly reduced and an improved scaling behaviour of the\nsimulation algorithm with respect to the quark mass is achieved."
    },
    {
        "anchor": "Spontaneous Chiral Symmetry Breaking as Condensation of Dynamical\n  Chirality: The occurrence of spontaneous chiral symmetry breaking (SChSB) is equivalent\nto sufficient abundance of Dirac near-zeromodes. However, dynamical mechanism\nleading to breakdown of chiral symmetry should be naturally reflected in chiral\nproperties of the modes. Here we offer such connection, presenting evidence\nthat SChSB in QCD proceeds via the appearance of modes exhibiting dynamical\ntendency for local chiral polarization. These modes form a band of finite width\nLambda_ch (chiral polarization scale) around the surface of otherwise\nanti--polarized Dirac sea, and condense. Lambda_ch characterizes the dynamics\nof the breaking phenomenon and can be converted to a quark mass scale, thus\noffering conceptual means to determine which quarks of nature are governed by\nbroken chiral dynamics. It is proposed that, within the context of SU(3) gauge\ntheories with fundamental Dirac quarks, mode condensation is equivalent to\nchiral polarization. This makes Lambda_ch an \"order parameter\" of SChSB, albeit\nwithout local dynamical field representation away from chiral limit. Several\nuses of these features, both at zero and finite temperature, are discussed. Our\ninitial estimates are Lambda_ch~150 MeV (N_f=0), Lambda_ch~80 MeV (N_f=2+1,\nphysical point), and that the strange quark is too heavy to be crucially\ninfluenced by broken chiral symmetry.",
        "positive": "Three-body dynamics of the $a_1(1260)$ resonance from lattice QCD: Resonant hadronic systems often exhibit a complicated decay pattern in which\nthree-body dynamics play a relevant or even dominant role. In this work we\nfocus on the $a_1(1260)$ resonance. For the first time, the pole position and\nbranching ratios of a three-body resonance are calculated from lattice QCD\nusing one-, two-, and three-meson interpolators and a three-body finite-volume\nformalism extended to spin and coupled channels. This marks a new milestone for\nab-initio studies of ordinary resonances along with hybrid and exotic hadrons\ninvolving three-body dynamics."
    },
    {
        "anchor": "Critical behavior of the compact 3d U(1) theory in the limit of zero\n  spatial coupling: Critical properties of the compact three-dimensional U(1) lattice gauge\ntheory are explored at finite temperatures on an asymmetric lattice. For\nvanishing value of the spatial gauge coupling one obtains an effective\ntwo-dimensional spin model which describes the interaction between Polyakov\nloops. We study numerically the effective spin model for N_t=1,4,8 on lattices\nwith spatial extension ranging from L=64 to L=256. Our results indicate that\nthe finite-temperature U(1) lattice gauge theory belongs to the universality\nclass of the two-dimensional XY model, thus supporting the Svetitsky-Yaffe\nconjecture.",
        "positive": "A novel algorithm for computing quark propagators for lattice hadron\n  spectroscopy: We report on our progress in computing the excitation spectrum in Lattice\nQCD. We focus on the isospin 0, 1 and 2 channels using the stochastic LapH\nalgorithm for the quark propagators. For the isospin-0 channel, a new glueball\noperator constructed from the stochastic LapH operator is included in the\nvariational basis along with the isoscalar meson and pi-pi operators. A\nrepresentative signal for each channel is presented and the feasibility of\nextending the calculations to larger lattices is discussed."
    },
    {
        "anchor": "Magnetic catalysis in the $1$-flavor Gross-Neveu model in $2+1$\n  dimensions: We investigate the Gross-Neveu model in $2+1$ dimensions in a constant and\nhomogeneous magnetic field using one reducible flavor of overlap fermions. Our\nlattice simulations suggest that the magnetic catalysis phenomenon, i.e., an\nincrease of the chiral condensate with the magnetic field, is present for all\ntemperatures below the chiral phase transition, in accordance with predictions\nfrom mean-field and beyond-mean-field calculations.",
        "positive": "The Self-Energy of Massive Lattice Fermions: We address the perturbative renormalization of massive lattice fermions. We\nderive expressions-valid to all orders in perturbation theory and for all\nvalues of the bare fermion mass-for the rest mass, the kinetic mass, and the\nwave-function renormalization factor. We obtain the fermion's self energy at\nthe one-loop level with a mass-dependent, $O(a)$ improved action. Numerical\nresults for two interesting special cases, the Wilson and\nSheikholeslami-Wohlert actions, are given. The mass dependence of these results\nsmoothly connects the massless and infinite-mass limits, as expected. Combined\nwith Monte Carlo calculations our results can be employed to determine the\nquark masses in common renormalization schemes."
    },
    {
        "anchor": "Correlators of left charges and weak operators in finite volume chiral\n  perturbation theory: We compute the two-point correlator between left-handed flavour charges, and\nthe three-point correlator between two left-handed charges and one strangeness\nviolating \\Delta I=3/2 weak operator, at next-to-leading order in finite volume\nSU(3)_L x SU(3)_R chiral perturbation theory, in the so-called epsilon-regime.\nMatching these results with the corresponding lattice measurements would in\nprinciple allow to extract the pion decay constant F, and the effective chiral\ntheory parameter g_27, which determines the \\Delta I = 3/2 amplitude of the\nweak decays K to \\pi\\pi as well as the kaon mixing parameter B_K in the chiral\nlimit. We repeat the calculations in the replica formulation of quenched chiral\nperturbation theory, finding only mild modifications. In particular, a properly\nchosen ratio of the three-point and two-point functions is shown to be\nidentical in the full and quenched theories at this order.",
        "positive": "Nucleon mass: from lattice QCD to the chiral limit: Previous extrapolations of lattice QCD results for the nucleon mass to the\nphysically relevant region of small quark masses, using chiral effective field\ntheory, are extended and expanded in several directions. A detailed error\nanalysis is performed. An approach with explicit delta(1232) degrees of freedom\nis compared to a calculation with only pion and nucleon degrees of freedom. The\nrole of the delta(1232) for the low-energy constants of the latter theory is\nelucidated. The consistency with the chiral perturbation theory analysis of\npion-nucleon scattering data is examined. It is demonstrated that this\nconsistency can indeed be achieved if the delta(1232) dominance of the P-wave\npion-nucleon low-energy constant c3 is accounted for. Introduction of the\ndelta(1232) as an explicit propagating degree of freedom is not crucial in\norder to describe the quark-mass dependence of the nucleon mass, in contrast to\nthe situation with spin observables of the nucleon. The dependence on finite\nlattice volume is shown to yield valuable additional constraints. What emerges\nis a consistent and stable extrapolation scheme for pion masses below 0.6 GeV."
    },
    {
        "anchor": "Monte Carlo overrelaxation for SU(N) gauge theories: The standard approach to Monte Carlo simulations of SU(N) Yang-Mills theories\nupdates successive SU(2) subgroups of each SU(N) link. We follow up on an old\nproposal of Creutz, to perform overrelaxation in the full SU(N) group instead,\nand show that it is more efficient.",
        "positive": "String breaking with 2+1 dynamical fermions using the stochastic LapH\n  method: The static potential $V(r)$ between a static quark and a static antiquark\nseparated by a distance r is defined as the energy of the ground state of the\nsystem. As a consequence of confinement, the energy between the quark-antiquark\npair is contained inside a color flux tube, which will break due to pair\ncreation as soon as the energy is high enough. String breaking is manifested as\na quantum-mechanical mixing phenomenon between different states containing two\ninfinitely heavy quarks. We investigate this phenomenon with $N_\\mathrm{f}=2+1$\nflavors of dynamical fermions in the stochastic LapH framework, using an\nensemble of gauge configurations generated through the CLS effort. We observe\nthe effect of the third sea-quark flavor, which results in a second\nmixing-phenomenon."
    },
    {
        "anchor": "Topology with Dynamical Overlap Fermions: We perform dynamical QCD simulations with $n_f=2$ overlap fermions by hybrid\nMonte-Carlo method on $6^4$ to $8^3\\times 16$ lattices. We study the problem of\ntopological sector changing. A new method is proposed which works without\ntopological sector changes. We use this new method to determine the topological\nsusceptibility at various quark masses.",
        "positive": "Pseudoscalar correlators and the problem of the chiral limit in the\n  compact lattice QED with Wilson fermions: The phase diagram for the compact lattice QED with Wilson fermions is shown.\nWe discuss different methods for the calculation of the 'pion' mass $m_{\\pi}$\nnear the chiral transition point $\\kappa_c(\\beta )$."
    },
    {
        "anchor": "Bottom and charmed hadron spectroscopy from lattice QCD: A survey of recent lattice QCD simulations for the mass spectrum of bottom\nand charmed hadrons is presented.",
        "positive": "Lattice QCD - A guide for people who want results: Lattice QCD was invented thirty years ago but only in the last few years has\nit finally fulfilled its promise as a precision tool for calculations in hadron\nphysics. This review will cover the fundamentals of discretising QCD onto a\nspace-time lattice and how to reduce the errors associated with the\ndiscretisation. This 'improvement' is the key that has made the enormous\ncomputational task of a lattice QCD calculation tractable and enabled us to\nreach the recent milestone of precision calculations of simple 'gold-plated'\nhadron masses. Accurate decay matrix elements, such as those for leptonic and\nsemileptonic decays of heavy mesons needed by the B factory experimental\nprogramme, are now within sight. I will describe what goes into such\ncalculations and what the future prospects and limitations are."
    },
    {
        "anchor": "Higher-group symmetry in lattice gauge theories with restricted\n  topological sectors: In this paper, we give a brief overview of generalized symmetries from the\npoint of view of the lattice regularization as a fully regularized framework.\nAt first, we illustrate the generalization of 't~Hooft anomaly matching for\nhigher-form symmetries. Furthermore the main interest goes to the higher-group\nsymmetry. In particular, we find that the so-called $4$-group appears in the\nlattice Yang--Mills theory under modification of instanton sum.",
        "positive": "Parity breaking at high temperature and density: We investigate the question of parity breaking in three-dimensional Euclidean\nSU(2) gauge-Higgs theory by Monte Carlo simulations. We observe no sign of\nspontaneous parity breaking in the behaviour of both local and non-local gauge\ninvariant operators. However, the presence of parity odd terms in the action\ncan induce a phase transition to a parity odd ground state which is\ncharacterized by a Chern-Simons like condensate. The implications for various\nproposed scenarios of fermion number non-conservation is discussed."
    },
    {
        "anchor": "The Lattice Free Energy of QCD with Clover Fermions, up to Three-Loops: We calculate the perturbative value of the free energy in Lattice QCD, up to\nthree loops. Our calculation is performed using Wilson gluons and the\nSheikholeslami - Wolhert (clover) improved action for fermions.\n  The free energy is directly related to the average plaquette. To carry out\nthe calculation, we compute all relevant Feynman diagrams up to 3 loops, using\na set of automated procedures in Mathematica; numerical evaluation of the\nresulting loop integrals is performed on finite lattice, with subsequent\nextrapolation to infinite size.\n  The results are presented as a function of the fermion mass m, for any\nSU(N_c) gauge group, and for an arbitrary number of fermion flavors. In order\nto enable independent comparisons, we also provide the results on a per diagram\nbasis, for a specific mass value.",
        "positive": "Magnetic properties of light nuclei from lattice QCD: After a short review of Lattice QCD methodology and techniques, I summarize\nrecent results of Lattice QCD calculations of the interactions of nucleons and\nlight nuclei with magnetic fields at pion masses of 805 MeV and 450 MeV.\nInterestingly, the magnetic moments are found to be consistent with the\nexperimental values when given in terms of natural nuclear magnetons. The very\nlow-energy cross section for $np\\rightarrow d\\gamma$ is calculated and found to\nagree with the experimental measurement. First calculations of the magnetic\npolarizabilities of light nuclei are presented, with a large isovector\npolarizability observed for the nucleon at these heavier pion masses."
    },
    {
        "anchor": "Monopoles, abelian projection, and gauge invariance: A direct connection is proved between the Non-Abelian Bianchi\nIdentities(NABI), and the abelian Bianchi identities for the 't Hooft tensor.\nAs a consequence the existence of a non-zero magnetic current is related to the\nviolation of the NABI's and is a gauge-invariant property. The construction\nallows to show that not all abelian projections can be used to expose monopoles\nin lattice configurations: each field configuration with non-zero magnetic\ncharge identifies its natural projection, up to gauge transformations which\ntend to unity at large distances. It is shown that the so-called\nmaximal-abelian gauge is a legitimate choice. It is also proved, starting from\nthe NABI, that monopole condensation is a physical gauge invariant phenomenon,\nindependent of the choice of the abelian projection.",
        "positive": "In search of a scaling scalar glueball: Anisotropic lattices are an efficient means of studying the glueballs of QCD,\nhowever problems arise with simulations of the lightest, scalar state. The mass\nis strongly dependent on the lattice spacing, even when a mean-field improved\ngluon action is used. The nature and cause of these errors are discussed and\nthe scaling properties of the scalar from different lattice actions are\npresented."
    },
    {
        "anchor": "Calculation of Moments of Nucleon Structure Functions: Preliminary results are presented in our program to calculate low moments of\nstructure functions for the proton and neutron on a $24^3\\times32$ lattice at\n$\\beta=6.2$. A comparison is made for a variety of smeared nucleon sources and\npreliminary results for the calculation of the nucleon tensor charge are\npresented.",
        "positive": "Exploring the large-$N_c$ limit with one quark flavour: We use one-flavour QCD ($N_c=3$) as a proxy to understand $\\mathcal{N}=1$\nSYM. For our simulations, we use tree-level improved Wilson fermions and\nSymanzik improved gauge action. The hadron spectrum is obtained by using LapH\nsmearing for different masses and simulation volumes. We also report on our\nefforts to increase the number of colours in our simulations, where we find\nthat the simulations show increasing topological freezing for larger $N_c$."
    },
    {
        "anchor": "Measuring the entropy from shifted boundary conditions: We explore a new computational strategy for determining the equation of state\nof the SU(3) Yang-Mills theory. By imposing shifted boundary conditions, the\nentropy density is computed from the vacuum expectation value of the\noff-diagonal components T_{0k} of the energy-momentum tensor. A step-scaling\nfunction is introduced to span a wide range in temperature values. We present\npreliminary numerical results for the entropy density and its step-scaling\nfunction obtained at eight temperature values in the range T_c - 15 T_c. At\neach temperature, discretization effects are removed by simulating the theory\nat several lattice spacings and by extrapolating the results to the continuum\nlimit. Finite-size effects are always kept below the statistical errors. The\nabsence of ultraviolet power divergences and the remarkably small\ndiscretization effects allow for a precise determination of the step-scaling\nfunction in the explored temperature range. These findings establish this\nstrategy as a viable solution for an accurate determination of the equation of\nstate in a wide range of temperature values.",
        "positive": "Lattice calculation of the lowest-order hadronic contribution to the\n  muon anomalous magnetic momen: I present quenched domain wall fermion and 2+1 flavor improved Kogut-Susskind\nfermion calculations of the hadronic vacuum polarization which are used to\ncalculate the ${\\cal O}(\\alpha^2)$ hadronic contribution to the anomalous\nmagnetic moment of the muon. Together with previous quenched calcuations, the\nnew results confirm that in the quenched theory the hadronic contribution is\nsignifcantly smaller ($\\sim 30%$) than the value obtained from the total cross\nsection of $e^+e^-$ annhilation to hadrons. The 2+1 flavor results show an\nincreasing contribution to $g-2$ as the quark mass is reduced."
    },
    {
        "anchor": "From Quantum Link Models to D-Theory: A Resource Efficient Framework for\n  the Quantum Simulation and Computation of Gauge Theories: Quantum link models provide an extension of Wilson's lattice gauge theory in\nwhich the link Hilbert space is finite-dimensional and corresponds to a\nrepresentation of an embedding algebra. In contrast to Wilson's parallel\ntransporters, quantum links are intrinsically quantum degrees of freedom. In\nD-theory these discrete variables undergo dimensional reduction, thus giving\nrise to asymptotically free theories. In this way (1+1)-d CP(N-1) models emerge\nby dimensional reduction from (2+1)-d SU(N) quantum spin ladders, the (2+1)-d\nconfining U(1) gauge theory emerges from the Abelian Coulomb phase of a (3+1)-d\nquantum link model, and (3+1)-d QCD arises from a non-Abelian Coulomb phase of\na (4+1)-d SU(3) quantum link model, with chiral quarks arising naturally as\ndomain wall fermions. Thanks to their finite-dimensional Hilbert space and\ntheir economical mechanism of reaching the continuum limit by dimensional\nreduction, quantum link models provide a resource efficient framework for the\nquantum simulation and computation of gauge theories.",
        "positive": "Double parton distributions in the nucleon from lattice simulations: We provide a first study of Mellin moments of double parton distributions\n(DPDs) in the nucleon on the lattice, where we consider several combinations of\nquark flavors and polarizations. These are accessible through two-current\ncorrelations, which can be obtained by evaluating four-point functions. In this\ncontext we consider all possible Wick contractions, where for almost all of\nthem sufficiently clear signals are obtained. In the present study, we employ\nan $n_f = 2 + 1$ CLS ensemble on a $96 \\times 32^3$ lattice with lattice\nspacing $a = 0.0856\\ \\mathrm{fm}$ and the pseudoscalar masses $m_\\pi = 355\\\n\\mathrm{MeV}$ and $m_K = 441\\ \\mathrm{MeV}$."
    },
    {
        "anchor": "Connection between Tomboulis vortices and projection vortices: By using the freedom of picking a representative we explore connections\nbetween the Tomboulis SO(3)xZ(2) form of the partition function and the SU(2)\nform. We are able to express the monopole and vortex observables of the former\nin terms of configurations of the latter. Also we can measure Tomboulis and\nprojection vortex counters on the same configuration to search for\ncorrelations.",
        "positive": "Lattice study of the confinement/deconfinement transition in rotating\n  gluodynamics: We study the influence of relativistic rotation on the\nconfinement/deconfinement phase transition in gluodynamics by means of lattice\nsimulations. The simulation is performed in the reference frame which rotates\nwith the system under investigation, where rotation is reduced to external\ngravitational field. The Polyakov loop and its susceptibility are calculated\nfor various lattice parameters and values of angular velocities which are\ncharacteristic for heavy-ion collision experiments. Different types of boundary\nconditions (open, periodic, Dirichlet) are imposed in directions, orthogonal to\nrotation axis. It is shown, that the critical temperature of the\nconfinement/deconfinement transition in gluodynamics grows quadratically with\nincreasing angular velocity. This conclusion does not depend on the boundary\nconditions used in our study and we believe that this is universal property of\ngluodynamics. We also present first results of the study of the phase diagram\nof rotating QCD matter with fermions. The results indicate, that effect of the\nrotation on fermions is opposite to gluons: it leads to the decrease of the\ncritical temperature."
    },
    {
        "anchor": "Magnetic moments of vector, axial, and tensor mesons in lattice QCD: We present a calculation of magnetic moments for selected spin-1 mesons using\nthe techniques of lattice QCD. This is carried out by introducing progressively\nsmall static magnetic field on the lattice and measuring the linear response of\na hadron's mass shift. The calculations are done on $24^4$ quenched lattices\nusing standard Wilson actions, with $\\beta$=6.0 and pion mass down to 500 MeV.\nThe results are compared to those from the form factor method where available.",
        "positive": "Thermodynamics and heavy quark potential in N_f=2 dynamical QCD: We study N_f=2 lattice QCD with nonperturbatively improved Wilson fermions at\nfinite temperature on 16^3 \\cdot 8 lattices. We determine the transition\ntemperature at m_{\\pi}/m_{\\rho} \\sim 0.8 and lattice spacing as small as\n0.12fm. The string breaking at T < T_c is also studied. We find that the static\npotential can be fitted by a simple expression involving string model potential\nat finite temperature."
    },
    {
        "anchor": "Quenched Chiral Perturbation Theory for Heavy-light Mesons: We formulate quenched chiral perturbation theory for heavy-light mesons\ncoupled to pions, and calculate the one-loop chiral logarithmic corrections to\n$f_B$, $f_{B_{s}}$, $B_B$ and $B_{B_{s}}$. We also calculate these corrections\nfor ``partially quenched'' theories. In both theories, the chiral logarithms\ndiverge in the chiral limit, indicating that (partially) quenched theories\nshould not be used to study this limit. Comparing the chiral logarithms to\nthose in QCD, we estimate the errors caused by (partial) quenching. By forming\nsuitable ratios, we can reduce the uncertainties in our estimates.",
        "positive": "Imaginary chemical potentials and the phase of the fermionic determinant: A numerical technique is proposed for an efficient numerical determination of\nthe average phase factor of the fermionic determinant continued to imaginary\nvalues of the chemical potential. The method is tested in QCD with eight\nflavors of dynamical staggered fermions. A direct check of the validity of\nanalytic continuation is made on small lattices and a study of the scaling with\nthe lattice volume is performed."
    },
    {
        "anchor": "Lattice investigation of the scalar mesons a_0(980) and \u03ba using\n  four-quark operators: We carry out an exploratory study of the isospin one a0(980) and the isospin\none-half kappa scalar mesons using Nf=2+1+1 Wilson twisted mass fermions at one\nlattice spacing. The valence strange quark is included as an Osterwalder-Seiler\nfermion with mass tuned so that the kaon mass matches the corresponding mass in\nthe unitary Nf=2+1+1 theory. We investigate the internal structure of these\nmesons by using a basis of four-quark interpolating fields. We construct\ndiquark-diquark and molecular-typecinterpolating fields and analyse the\nresulting correlation matrices keeping only connected contributions. For both\nchannels, the low-lying spectrum is found to be consistent with two-particle\nscattering states. Therefore, our analysis shows no evidence for an additional\nstate that can be interpreted as either a tetraquark or a tightly-bound\nmolecular state.",
        "positive": "Order a improved renormalization constants: We present non-perturbative results for the constants needed for on-shell\n$O(a)$ improvement of bilinear operators composed of Wilson fermions. We work\nat $\\beta=6.0$ and 6.2 in the quenched approximation. The calculation is done\nby imposing axial and vector Ward identities on correlators similar to those\nused in standard hadron mass calculations. A crucial feature of the calculation\nis the use of non-degenerate quarks. We also obtain results for the constants\nneeded for off-shell $O(a)$ improvement of bilinears, and for the scale and\nscheme independent renormalization constants, (Z_A), (Z_V) and (Z_S/Z_P).\nSeveral of the constants are determined using a variety of different Ward\nidentities, and we compare their relative efficacies. In this way, we find a\nmethod for calculating $c_V$ that gives smaller errors than that used\npreviously. Wherever possible, we compare our results with those of the ALPHA\ncollaboration (who use the Schr\\\"odinger functional) and with 1-loop\ntadpole-improved perturbation theory."
    },
    {
        "anchor": "Large N: I review some of the things we have learned about large N gauge theories (and\nQCD at N=oo) from lattice calculations in recent years. I point to some open\nproblems.",
        "positive": "Towards the continuum limit with quenched staggered quarks: We extend previous work on finite-size effects with dynamical staggered\nquarks to the quenched approximation. We again emphasize the large volume limit\nthat is of interest for spectrum calculations which may hope to approach the\nexperimental values. Relying on new calculations at $6/g^2=5.7$ and recent work\nwith weaker couplings, we extrapolate to the continuum limit and find a nucleon\nto rho mass ratio in close agreement with the experimental value and the value\nobtained by extrapolations from calculations with Wilson quarks. Additional\ncalculations that should be done to improve the reliability of the\nextrapolation are discussed."
    },
    {
        "anchor": "On the fractal structure of two-dimensional quantum gravity: We provide evidence that the Hausdorff dimension is 4 and the spectral\ndimension is 2 for two-dimensional quantum gravity coupled the matter with a\ncentral charge $c \\leq 1$. For $c > 1$ the Hausdorff dimension and the spectral\ndimension monotonously decreases to 2 and 1, respectively.",
        "positive": "Inverse Laplace transform on the lattice spacing: Inverse Laplace transform on the lattice spacing is introduced as a\ncomputational framework of the extrapolation of the strong coupling expansion\nto the scaling region. We apply the transform to the two-dimensional non-linear\nO(N) model at N>=3 and show that the approximation of the continuum limit of\nthe susceptibility agrees with the existing theoretical and Monte Carlo data."
    },
    {
        "anchor": "An accurate calculation of the nucleon axial charge with lattice QCD: We report on a lattice QCD calculation of the nucleon axial charge, $g_A$,\nusing M\\\"{o}bius Domain-Wall fermions solved on the dynamical $N_f=2+1+1$ HISQ\nensembles after they are smeared using the gradient-flow algorithm. The\ncalculation is performed with three pion masses, $m_\\pi\\sim\\{310,220,130\\}$\nMeV. Three lattice spacings ($a\\sim\\{0.15,0.12,0.09\\}$ fm) are used with the\nheaviest pion mass, while the coarsest two spacings are used on the middle pion\nmass and only the coarsest spacing is used with the near physical pion mass. On\nthe $m_\\pi\\sim220$ MeV, $a\\sim0.12$ fm point, a dedicated volume study is\nperformed with $m_\\pi L \\sim \\{3.22,4.29,5.36\\}$. Using a new strategy\nmotivated by the Feynman-Hellmann Theorem, we achieve a precise determination\nof $g_A$ with relatively low statistics, and demonstrable control over the\nexcited state, continuum, infinite volume and chiral extrapolation systematic\nuncertainties, the latter of which remains the dominant uncertainty. Our final\ndetermination at 2.6\\% total uncertainty is $g_A = 1.278(21)(26)$, with the\nfirst uncertainty including statistical and systematic uncertainties from\nfitting and the second including model selection systematics related to the\nchiral and continuum extrapolation. The largest reduction of the second\nuncertainty will come from a greater number of pion mass points as well as more\nprecise lattice QCD results near the physical pion mass.",
        "positive": "An Euclidean representation of Majorana spins: An Euclidean representation of bosonized Majorana fermions, prior to imposing\nconstraints, is derived in three space-time dimensons. The difference with the\nstandard three dimensional Ising system is epmhasized. The mild sign problem,\ndoes not preclude Monte Carlo simulations in intermediate volumes. Implementing\nconstraints is briefly outlined."
    },
    {
        "anchor": "Do Large Abelian Monopole Loops Survive the Continuum Limit?: An analysis of the monopole loop length distribution is performed in\nWilson-action SU(2) lattice gauge theory. A pure power law in the inverse\nlength is found, at least for loops of length, $l$, less than the linear\nlattice size $N$. This power shows a definite $\\beta$ dependence, passing 5\naround $\\beta =2.9$, and appears to have very little finite lattice size\ndependence. It is shown that when this power exceeds 5, no loops any finite\nfraction of the lattice size will survive the infinite lattice limit. This is\ntrue for any reasonable size distribution for loops larger than N. The apparent\nlack of finite size dependence in this quantity would seem to indicate that\nabelian monopole loops large enough to cause confinement do not survive the\ncontinuum limit. Indeed they are absent for all $\\beta > 2.9$.",
        "positive": "Spectral properties of the Landau gauge Faddeev-Popov operator in\n  lattice gluodynamics: Recently we reported on the infrared behavior of the Landau gauge gluon and\nghost dressing functions in SU(3) Wilson lattice gluodynamics with special\nemphasis on the Gribov problem. Here we add an investigation of the spectral\nproperties of the Faddeev-Popov operator at $\\beta$=5.8 and 6.2 for lattice\nsizes 12^4, 16^4 and 24^4. The larger the volume the more of its eigenvalues\nare found accumulated close to zero. Using the eigenmodes for the spectral\nrepresentation it turns out that for our smallest lattice O(200) eigenmodes are\nsufficient to saturate the ghost propagator at lowest momentum. We associate\nexceptionally large values of the ghost propagator to extraordinary\ncontributions of low-lying eigenmodes."
    },
    {
        "anchor": "Finite-size scaling around the critical point in the heavy quark region\n  of QCD: Finite-size scaling is investigated in detail around the critical point in\nthe heavy-quark region of nonzero temperature QCD. Numerical simulations are\nperformed with large spatial volumes up to the aspect ratio $N_s/N_t=12$ at a\nfixed lattice spacing with $N_t=4$. We show that the Binder cumulant and the\ndistribution function of the Polyakov loop follow the finite-size scaling in\nthe $Z(2)$ universality class for large spatial volumes with $N_s/N_t \\ge 9$,\nwhile, for $N_s/N_t \\le 8$, the Binder cumulant becomes inconsistent with the\n$Z(2)$ scaling. To realize the large-volume simulations in the heavy-quark\nregion, we adopt the hopping parameter expansion for the quark determinant: We\ngenerate gauge configurations using the leading order action including the\nPolyakov loop term for $N_t=4$, and incorporate the next-to-leading order\neffects in the measurements by the multipoint reweighting method. We find that\nthe use of the leading-order configurations is crucially effective in\nsuppressing the overlapping problem in the reweighting and thus reducing the\nstatistical errors.",
        "positive": "Center clusters in the Yang-Mills vacuum: Properties of local Polyakov loops for SU(2) and SU(3) lattice gauge theory\nat finite temperature are analyzed. We show that spatial clusters can be\nidentified where the local Polyakov loops have values close to the same center\nelement. For a suitable definition of these clusters the deconfinement\ntransition can be characterized by the onset of percolation in one of the\ncenter sectors. The analysis is repeated for different resolution scales of the\nlattice and we argue that the center clusters have a continuum limit."
    },
    {
        "anchor": "The $\u03b7\\rightarrow \u03b3^* \u03b3^*$ transition form factor and the\n  hadronic light-by-light $\u03b7$-pole contribution to the muon $g-2$ from\n  lattice QCD: We calculate the double-virtual $\\eta \\rightarrow \\gamma^* \\gamma^*$\ntransition form factor $\\mathcal{F}_{\\eta \\to \\gamma^* \\gamma^*}(q_1^2,q_2^2)$\nfrom first principles using a lattice QCD simulation with $N_f=2+1+1$ quark\nflavors at the physical pion mass and at one lattice spacing and volume. The\nkinematic range covered by our calculation is complementary to the one\naccessible from experiment and is relevant for the $\\eta$-pole contribution to\nthe hadronic light-by-light scattering in the anomalous magnetic moment $a_\\mu\n= (g-2)/2$ of the muon. From the form factor calculation we extract the partial\ndecay width $\\Gamma(\\eta \\rightarrow \\gamma \\gamma) =\n323(85)_\\text{stat}(22)_\\text{syst}$ eV and the slope parameter\n$b_\\eta=1.19(36)_\\text{stat}(16)_\\text{syst}$ GeV${}^{-2}$. For the $\\eta$-pole\ncontribution to $a_\\mu$ we obtain $a_\\mu^{\\eta-\\text{pole}} =\n13.2(5.2)_\\text{stat}(1.3)_\\text{syst} \\cdot 10^{-11}$.",
        "positive": "Effects of non-perturbatively improved dynamical fermions in QCD at\n  fixed lattice spacing: We present results for the static inter-quark potential, lightest glueballs,\nlight hadron spectrum and topological susceptibility using a non-perturbatively\nimproved action on a $16^3\\times 32$ lattice at a set of values of the bare\ngauge coupling and bare dynamical quark mass chosen to keep the lattice size\nfixed in physical units ($\\sim 1.7$ fm). By comparing these measurements with a\nmatched quenched ensemble, we study the effects due to two degenerate flavours\nof dynamical quarks. With the greater control over residual lattice spacing\neffects which these methods afford, we find some evidence of charge screening\nand some minor effects on the light hadron spectrum over the range of quark\nmasses studied ($M_{PS}/M_{V}\\ge0.58$). More substantial differences between\nquenched and unquenched simulations are observed in measurements of topological\nquantities."
    },
    {
        "anchor": "Gluelump masses and mass splittings from SU(3) lattice gauge theory: We compute gluelump masses and mass differences using SU(3) lattice gauge\ntheory. We study states with total angular momentum up to $J = 3$, parity $P =\n+,-$ and charge conjugation $C = +,-$. Computations on four ensembles with\nrather fine lattice spacings in the range $0.040 \\, \\text{fm} \\ldots 0.093 \\,\n\\text{fm}$ allow continuum extrapolations of gluelump mass differences. We\ncomplement existing results on hybrid static potentials with the obtained\ngluelump masses, which represent the limit of vanishing quark-antiquark\nseparation. We also discuss the conversion of lattice gluelump masses to the\nRenormalon Subtracted scheme, which is e.g. important for studies of heavy\nhybrid mesons in the Born-Oppenheimer approximation.",
        "positive": "CP invariance of chiral gauge theories and Majorana-Yukawa couplings on\n  the lattice: The construction of CP-invariant lattice chiral gauge theories and the\nconstruction of lattice Majorana fermions with chiral Yukawa couplings is\nsubject to topological obstructions. In the present work we suggest lattice\nextensions of charge and parity transformation for Weyl fermions. This enables\nus to construct lattice chiral gauge theories that are CP invariant. For the\nconstruction of Majorana-Yukawa couplings, we discuss two models with\nsymplectic Majorana fermions: a model with two symplectic doublets, and one\nwith an auxiliary doublet."
    },
    {
        "anchor": "Disorder operators and magnetic vortices in SU(N) lattice gauge theory: We construct the most general disorder operator for SU(N) lattice gauge\ntheory in $(2+1)$ dimension by using exact duality transformations. These\ndisorder operators, defined on the plaquettes and characterized by\n($\\text{N}-1$) angles, are the creation \\& annihilation or the shift operators\nfor the SU(N) magnetic vortices carrying $(\\text{N}-1)$ types of magnetic\nfluxes. They are dual to the SU(N) Wilson loop order operators which, on the\nother hand, are the creation-annihilation or shift operators for the\n$(\\text{N}-1)$ electric fluxes on their loops. The new order-disorder algebra\ninvolving SU(N) Wigner D matrices is derived and discussed. The $Z_\\text{N}\n(\\in $ SU(N)) 't Hooft operator is obtained as a special limit. In this limit\nwe also recover the standard Wilson-'t Hooft order-disorder algebra. The\npartition function representation and the free energies of these SU(N) magnetic\nvortices are discussed.",
        "positive": "Reducing Autocorrelation Times in Lattice Simulations with Generative\n  Adversarial Networks: Short autocorrelation times are essential for a reliable error assessment in\nMonte Carlo simulations of lattice systems. In many interesting scenarios, the\ndecay of autocorrelations in the Markov chain is prohibitively slow. Generative\nsamplers can provide statistically independent field configurations, thereby\npotentially ameliorating these issues. In this work, the applicability of\nneural samplers to this problem is investigated. Specifically, we work with a\ngenerative adversarial network (GAN). We propose to address difficulties\nregarding its statistical exactness through the implementation of an\noverrelaxation step, by searching the latent space of the trained generator\nnetwork. This procedure can be incorporated into a standard Monte Carlo\nalgorithm, which then permits a sensible assessment of ergodicity and balance\nbased on consistency checks. Numerical results for real, scalar $\\phi^4$-theory\nin two dimensions are presented. We achieve a significant reduction of\nautocorrelations while accurately reproducing the correct statistics. We\ndiscuss possible improvements to the approach as well as potential solutions to\npersisting issues."
    },
    {
        "anchor": "Form factors from lattice QCD: Precision computation of hadronic physics with lattice QCD is becoming\nfeasible. The last decade has seen percent-level calculations of many simple\nproperties of mesons, and the last few years have seen calculations of baryon\nmasses, including the nucleon mass, accurate to a few percent. As computational\npower increases and algorithms advance, the precise calculation of a variety of\nmore demanding hadronic properties will become realistic. With this in mind, I\ndiscuss the current lattice QCD calculations of generalized parton\ndistributions with an emphasis on the prospects for well-controlled\ncalculations for these observables as well. I will do this by way of several\nexamples: the pion and nucleon form factors and moments of the nucleon parton\nand generalized-parton distributions.",
        "positive": "Lattice monopoles in hot SU(2) gluodynamics as blocked continuum defects: We propose to consider lattice monopoles in gluodynamics as continuum\nmonopoles blocked to the lattice. In this approach the lattice is associated\nwith a measuring device consisting of finite-sized detectors of monopoles\n(lattice cells). Thus a continuum monopole theory defines the dynamics of the\nlattice monopoles. We apply this idea to the static monopoles in high\ntemperature gluodynamics. We show that our suggestion allows to describe the\nnumerical data both for the density of the lattice monopoles and for the\nlattice monopole action in terms of a continuum Coulomb gas model."
    },
    {
        "anchor": "Properties of hadron screening masses at small baryonic density: The properties of hadron screening masses around the deconfinement phase\ntransition at finite baryonic density can be studied by evaluating the Taylor\ncoefficients with respect to the iso-scalar and iso-vector chemical potentials.\nWe simulate 2-flavour lattice QCD with staggered fermions on a 12*12*24*6\nlattice with ma = 0.05 and 0.10 and report investigations of nucleon,\npseudo-scalar and vector mesons. We present new, strong evidence that in the\nconfining phase, the screening masses at vanishing chemical potential have\nsignificant temperature dependence, but the effect of the iso-scalar chemical\npotential is very small. Above the critical temperature, the second derivative\nterms of mesons rapidly increase as contrasted to the case of baryon. We also\nstudy the responses of the screening masses to an iso-vector chemical potential\nand discuss some of the issues related to the properties of hadron masses at\nfinite density.",
        "positive": "Search for the IR fixed point in the twisted Polyakov loop scheme: We present a non-perturbative study of the running coupling constant in the\nTwisted Polyakov Loop (TPL) scheme. We investigate how the systematic and\nstatistical errors can be controlled {\\it via} a feasibility study in SU(3)\npure Yang-Mills theory. We show that our method reproduces the perturbative\ndetermination of the running coupling in the UV. In addition, our numerical\nresult agrees with the theoretical prediction of this coupling constant in the\nIR. We also present our preliminary results for $N_f=12$ QCD, where an IR fixed\npoint may be present."
    },
    {
        "anchor": "Fighting topological freezing in the two-dimensional CP$^{N-1}$ model: We perform Monte Carlo simulations of the CP$^{N-1}$ model on the square\nlattice for $N=10$, $21$, and $41$. Our focus is on the severe slowing down\nrelated to instantons. To fight this problem we employ open boundary conditions\nas proposed by L\\\"uscher and Schaefer for lattice QCD. Furthermore we test the\nefficiency of parallel tempering of a line defect. Our results for open\nboundary conditions are consistent with the expectation that topological\nfreezing is avoided, while autocorrelation times are still large. The results\nobtained with parallel tempering are encouraging.",
        "positive": "Charm physics with a tmQCD mixed action: We report on our ongoing determination of the charm quark mass and the masses\nand decay constants of various charmed mesons, obtained within a mixed-action\nsetup. We employ $N_f=2+1$ CLS ensembles combined with a Wilson twisted mass\nvalence action that eliminates the leading $O(a)$ effects from our target\nobservables. Alongside our preliminary results, we will discuss an exploration\nof GEVP techniques aimed at optimizing the precision in view of the extension\nof the computation to heavier quark masses. We study the chiral-continuum\nextrapolation of decay constants for charm quark observables and the\nrenormalized charm quark mass."
    },
    {
        "anchor": "The nucleon electric dipole moment with the gradient flow: the\n  $\u03b8$-term contribution: We propose a new method to calculate electric dipole moments induced by the\nstrong QCD $\\theta$-term. The method is based on the gradient flow for gauge\nfields and is free from renormalization ambiguities. We test our method by\ncomputing the nucleon electric dipole moments in pure Yang-Mills theory at\nseveral lattice spacings, enabling a first-of-its-kind continuum extrapolation.\nThe method is rather general and can be applied for any quantity computed in a\n$\\theta$ vacuum. This first application of the gradient flow has been\nsuccessful and demonstrates proof-of-principle, thereby providing a novel\nmethod to obtain precise results for nucleon and light nuclear electric dipole\nmoments.",
        "positive": "Hybrid Monte Carlo algorithm for lattice QCD with two flavors of\n  dynamical Ginsparg-Wilson quarks: We study aspects concerning numerical simulations of Lattice QCD with two\nflavors of dynamical Ginsparg-Wilson quarks with degenerate masses. A Hybrid\nMonte Carlo algorithm is described and the formula for the fermionic force is\nderived for two specific implementations. The implementation with optimal\nrational approximation method is favored both in CPU time and memory\nconsumption."
    },
    {
        "anchor": "Numerical study of the Yang-Mills vacuum wavefunctional in D=3+1\n  dimensions: Ratios of the true Yang-Mills vacuum wavefunctional, evaluated on any two\nfield configurations out of a finite set of configurations, can be obtained\nfrom lattice Monte Carlo simulations. The method was applied some years ago to\ntest various proposals for the vacuum wavefunctional in 2+1 dimensions. In this\narticle we use the same method to test our own proposal for the Yang-Mills\nground state in 3+1 dimensions. This state has the property of \"dimensional\nreduction\" at large scales, meaning that the (squared) vacuum state, evaluated\non long-wavelength, large scale fluctuations, has the form of the Boltzmann\nweight for Yang-Mills theory in D=3 Euclidean dimensions. Our numerical results\nsupport this conjectured behavior. We also investigate the form of the ground\nstate evaluated on shorter wavelength configurations.",
        "positive": "Polarized structure functions from the lattice: We give a brief sketch of lattice structure function calculations and review\nprevious results for the axial coupling $g_A$. We outline a new technique for\ntreating fermions on the lattice that preserves chiral symmetry, domain wall\nfermions. Finally, we give preliminary results for the nucleon spectrum using\nthis new technique. Remarkably, a large mass splitting between the $N$ and\n$N^*$, roughly consistent with experiment, is produced in the calculation.\nThese results are encouraging for proposed calculations of nucleon structure\nfunctions."
    },
    {
        "anchor": "London penetration depth and coherence length of SU(3) vacuum flux tubes: The transverse profile of the chromoelectric field generated by a\nquark-antiquark pair in the SU(3) vacuum is analysed within the dual\nsuperconductor scenario, then the London penetration depth and coherence length\nare extracted. The color field is determined on the lattice through a connected\ncorrelator of two Polyakov loops measured on smeared configurations.",
        "positive": "Numerical study of large-N phase transition of smeared Wilson loops in\n  4D pure YM theory: In Euclidean four-dimensional SU(N) pure gauge theory, eigenvalue\ndistributions of Wilson loop parallel transport matrices around closed\nspacetime curves show non-analytic behavior (a 'large-N phase transition') at a\ncritical size of the curve. We focus mainly on an observable composed of traces\nof the Wilson loop operator in all totally antisymmetric representations, which\nis regularized with the help of smearing. By studying sequences of square\nWilson loops on a hypercubic lattice with standard Wilson action, it is shown\nthat this observable has a nontrivial continuum limit as a function of the\nphysical size of the loop. We furthermore present (preliminary) numerical\nresults confirming that, for large N, the N dependence in the critical regime\nis governed by the universal exponents 1/2 and 3/4 as expected (Burgers\nuniversality)."
    },
    {
        "anchor": "The Spatial String Tension and Dimensional Reduction in QCD: We calculate the spatial string tension in (2+1) flavor QCD with physical\nstrange quark mass and almost physical light quark masses using lattices with\ntemporal extent N_tau=4,6 and 8. We compare our results on the spatial string\ntension with predictions of dimensionally reduced QCD. This suggests that also\nin the presence of light dynamical quarks dimensional reduction works well down\nto temperatures 1.5T_c.",
        "positive": "Regressive and generative neural networks for scalar field theory: We explore the perspectives of machine learning techniques in the context of\nquantum field theories. In particular, we discuss two-dimensional complex\nscalar field theory at nonzero temperature and chemical potential -- a theory\nwith a nontrivial phase diagram. A neural network is successfully trained to\nrecognize the different phases of this system and to predict the value of\nvarious observables, based on the field configurations. We analyze a broad\nrange of chemical potentials and find that the network is robust and able to\nrecognize patterns far away from the point where it was trained. Aside from the\nregressive analysis, which belongs to supervised learning, an unsupervised\ngenerative network is proposed to produce new quantum field configurations that\nfollow a specific distribution. An implicit local constraint fulfilled by the\nphysical configurations was found to be automatically captured by our\ngenerative model. We elaborate on potential uses of such a generative approach\nfor sampling outside the training region."
    },
    {
        "anchor": "Domain Wall Fermions in Quenched Lattice QCD: We study the chiral properties and the validity of perturbation theory for\ndomain wall fermions in quenched lattice QCD at beta=6.0. The explicit chiral\nsymmetry breaking term in the axial Ward-Takahashi identity is found to be very\nsmall already at Ns=10, where Ns is the size of the fifth dimension, and its\nbehavior seems consistent with an exponential decay in Ns within the limited\nrange of Ns we explore. From the fact that the critical quark mass, at which\nthe pion mass vanishes as in the case of the ordinary Wilson-type fermion,\nexists at finite Ns, we point out that this may be a signal of the parity\nbroken phase and investigate the possible existence of such a phase in this\nmodel at finite Ns. The rho and pi meson decay constants obtained from the\nfour-dimensional local currents with the one-loop renormalization factor show a\ngood agreement with those obtained from the conserved currents.",
        "positive": "Dual Superconductor Scenario of Confinement: A Systematic Study of\n  Gribov Copy Effects: We perform a study of the effects from maximal abelian gauge Gribov copies in\nthe context of the dual superconductor scenario of confinement, on the basis of\na novel approach for estimation of systematic uncertainties from incomplete\ngauge fixing. We present numerical results, in SU(2) lattice gauge theory,\nusing the overrelaxed simulated annealing gauge fixing algorithm. We find\nabelian and non-abelian string tensions to differ significantly, their ratio\nbeing 0.92(4) at BETA = 2.5115. An approximate factorization of the abelian\npotential into monopole and photon contributions has been confirmed, the former\ngiving rise to the abelian string tension."
    },
    {
        "anchor": "A better large $N$ expansion for chiral Yukawa models: We consider the most general renormalizable chiral Yukawa model with\n$SU(3)_{\\rm color}$ replaced by $SU(N_c)$, $SU(2)_{\\rm L}$ replaced by $SU(N_w\n)$ and $U(1)_{Y}$ replaced by $U(1)^{N_w -1}$ in the limit $N_c\n\\rightarrow\\infty$, $N_w \\rightarrow\\infty$ with the ratio\n$\\rho=\\sqrt{{N_w}\\over{N_c}} \\ne 0,\\infty$ held fixed. Since for $N_w \\ge 3$\nonly one renormalizable Yukawa coupling per family exists and there is no\nmixing between families the limit is appropriate for the description of the\neffects of a heavy top quark when all the other fermions are taken to be\nmassless. The large $N=\\sqrt{N_{c} N_{w}}$ expansion is expected to be no worse\nquantitatively in this model that in the purely scalar case and the $N=\\infty$\nlimit is soluble even when the model is regularized non--perturbatively. A\nrough estimate of the triviality bound on the Yukawa coupling is equivalent to\n$m_t \\le 1~TeV$.",
        "positive": "Evidence for chiral logarithms in the baryon spectrum: Using precise lattice QCD computations of the baryon spectrum, we present the\nfirst direct evidence for the presence of contributions to the baryon masses\nwhich are non-analytic in the light quark masses; contributions which are often\ndenoted \"chiral logarithms\". We isolate the poor convergence of SU(3) baryon\nchiral perturbation theory to the flavor-singlet mass combination. The\nflavor-octet baryon mass splittings, which are corrected by chiral logarithms\nat next to leading order in SU(3) chiral perturbation theory, yield baryon-pion\naxial coupling constants D, F, C and H consistent with QCD values; the first\nevidence of chiral logarithms in the baryon spectrum. The Gell-Mann--Okubo\nrelation, a flavor-27 baryon mass splitting, which is dominated by chiral\ncorrections from light quark masses, provides further evidence for the presence\nof non-analytic light quark mass dependence in the baryon spectrum; we\nsimultaneously find the GMO relation to be inconsistent with the first few\nterms in a taylor expansion in m_s - m_l, which must be valid for small values\nof this SU(3) breaking parameter. Additional, more definitive tests of SU(3)\nchiral perturbation theory will become possible with future, more precise,\nlattice calculations."
    },
    {
        "anchor": "A proposal for simulating QCD at finite chemical potential on the\n  lattice: An algorithm to simulate full QCD with 3 colours at nonzero chemical\npotential on the lattice is proposed. The algorithm works for small values of\nthe chemical potential and can be used to extract expectation values of CPT\ninvariant operators.",
        "positive": "Neutral B-meson mixing parameters in and beyond the SM with 2+1 flavor\n  lattice QCD: We report on the status of our calculation of the hadronic matrix elements\nfor neutral $B$-meson mixing with asqtad sea and valence light quarks and using\nthe Wilson clover action with the Fermilab interpretation for the $b$ quark. We\ncalculate the matrix elements of all five local operators that contribute to\nneutral $B$-meson mixing both in and beyond the Standard Model. We use MILC\nensembles with $N_f=2+1$ dynamical flavors at four different lattice spacings\nin the range $a \\approx 0.045$--$0.12$~fm, and with light sea-quark masses as\nlow as 0.05 times the physical strange quark mass. We perform a combined\nchiral-continuum extrapolation including the so-called wrong-spin contributions\nin simultaneous fits to the matrix elements of the five operators. We present a\ncomplete systematic error budget and conclude with an outlook for obtaining\nfinal results from this analysis."
    },
    {
        "anchor": "Role of axial U(1) anomaly in chiral susceptibility of QCD at high\n  temperature: The chiral susceptibility, or the first derivative of the chiral condensate\nwith respect to the quark mass, is often used as a probe for the QCD phase\ntransition since the chiral condensate is an order parameter of $SU(2)_L \\times\nSU(2)_R$ symmetry breaking. However, the chiral condensate also breaks the\naxial $U(1)$ symmetry, which is usually not paid attention to as it is already\nbroken by anomaly and apparently gives little impact on the transition. We\ninvestigate the susceptibilities in the scalar and pseudoscalar channels in\norder to quantify how much the axial $U(1)$ breaking contributes to the chiral\nphase transition. Employing a chirally symmetric lattice Dirac operator, and\nits eigenmode decomposition, we separate the axial $U(1)$ breaking effects from\nothers. Our result in two-flavor QCD indicates that both of the connected and\ndisconnected chiral susceptibilities are dominated by the axial $U(1)$ breaking\nat temperatures $T\\gtrsim 190$ MeV after the quadratically divergent constant\nis subtracted.",
        "positive": "Symanzik improvement of lattice QCD with four flavors of Wilson quarks: We have determined the non-perturbative O(a)-improvement coefficient c_sw for\nfour flavors of Wilson quarks with the plaquette gauge action in a range of\nbeta >= 5. The data are fitted with several Pade approximation formulae to get\nan impression of the stability. A small extrapolation below beta=5 seems\nacceptable."
    },
    {
        "anchor": "Towards the Application of Skewed Detailed Balance in Lattice Gauge\n  Theories: State-of-the-art algorithms in lattice gauge theory typically rely heavily on\ndetailed balance, which is an instrumental tool to prove the correct\nconvergence of the Markov Chain Monte Carlo Algorithm. In this work, we\ninvestigate an alternative to detailed balance, skewed detailed balance, and\nthe prospects of alleviating the topological freezing problem by studying the\none-dimensional $O\\left(2\\right)$ model.",
        "positive": "Contraction Diagram Analysis in Pion-Kaon Scattering: We study the contributions from the connected and disconnected contraction\ndiagrams to the pion-kaon scattering amplitude within the framework of\nSU$(4|1)$ partially-quenched chiral perturbation theory. Combining this with a\nfinite-volume analysis, we demonstrate that a lattice calculation of the easier\ncomputable connected correlation functions is able to provide valuable\ninformation of the noisier disconnected correlation functions, and may serve as\na theory guidance for the future refinement of the corresponding lattice\ntechniques."
    },
    {
        "anchor": "Gauge Fixing and the Gibbs Phenomenon: We address the question of why global gauge fixing, specifically to the\nlattice Landau gauge, becomes an extremely lengthy process for large lattices.\nWe construct an artificial \"gauge-fixing\" problem which has the essential\nfeatures encountered in actuality. In the limit in which the size of the system\nto be gauge fixed becomes infinite, the problem becomes equivalent to finding a\nseries expansion in functions which are related to the Jacobi polynomials. The\nseries converges slowly, as expected. It also converges non-uniformly, which is\nan observed characteristic of gauge fixing. In the limiting example, the\nnon-uniformity arises through the Gibbs phenomenon.",
        "positive": "Topology and chiral symmetry in finite temperature QCD: We investigate the realization of chiral symmetry in the vicinity of the\ndeconfinement transition in quenched QCD using overlap fermions. Via the index\ntheorem obeyed by the overlap fermions, we gain insight into the behavior of\ntopology at finite temperature. We find small eigenvalues, clearly separated\nfrom the bulk of the eigenvalues, and study the properties of their\ndistribution. We compare the distribution with a model of a dilute gas of\ninstantons and anti-instantons and find good agreement."
    },
    {
        "anchor": "Nucleon Decay Matrix Elements from Lattice QCD: We present a model-independent calculation of hadron matrix elements for all\ndimension-six operators associated with baryon number violating processes using\nlattice QCD. The calculation is performed with the Wilson quark action in the\nquenched approximation at $\\beta=6/g^2=6.0$ on a $28^2\\times 48\\times 80$\nlattice. Our results cover all the matrix elements required to estimate the\npartial lifetimes of (proton,neutron)$\\to$($\\pi,K,\\eta$) +(${\\bar\n\\nu},e^+,\\mu^+$) decay modes. We point out the necessity of disentangling two\nform factors that contribute to the matrix element; previous calculations did\nnot make the separation, which led to an underestimate of the physical matrix\nelements. With a correct separation, we find that the matrix elements have\nvalues 3-5 times larger than the smallest estimates employed in\nphenomenological analyses of the nucleon decays, which could give strong\nconstraints on several GUT models. We also find that the values of the matrix\nelements are comparable with the tree-level predictions of chiral lagrangian.",
        "positive": "Instantons and Monopoles: This study is part of a research program aimed to investigate the relations\nbetween instantons, monopoles, and chiral symmetry breaking. Monopoles are\nimportant 3-dimensional topological configurations existing in QCD, which are\nbelieved to produce colour confinement. Instantons are 4-dimensional\ntopological configurations and are known to be related to chiral symmetry\nbreaking. To study the relation between monopoles and instantons we generate\nconfigurations adding to the vacuum state static monopole-antimonopole pairs of\nopposite charges by use of a monopole creation operator. We observe that the\nmonopole creation operator only adds long monopole loops to the configurations.\nWe then count the number of fermion zero modes using Overlap fermions as a\ntool. As a result we find that each monopole-antimonopole pair of magnetic\ncharge one adds one zero mode of chirality $\\pm1$, i.e. one instanton of\ntopological charge $\\pm1$."
    },
    {
        "anchor": "The exact decomposition of gauge variables in lattice Yang-Mills theory: In this paper, we consider lattice versions of the decomposition of the Yang-\nMills field a la Cho-Faddeev-Niemi, which was extended by Kondo, Shinohara and\nMurakami in the continuum formulation. For the SU(N) gauge group, we propose a\nset of defining equations for specifying the decomposition of the gauge link\nvariable and solve them exactly without using the ansatz adopted in the\nprevious studies for SU(2) and SU(3). As a result, we obtain the general form\nof the decomposition for SU(N) gauge link variables and confirm the previous\nresults obtained for SU(2) and SU(3).",
        "positive": "Dual superconducting properties of the QCD vacuum: A consistent description of the confining QCD vacuum as a dual superconductor\nrequires a determination of fundamental parameters such as the superconductor\ncorrelation length $\\xi$ and the field penetration depth $\\lambda$, which\ndetermine whether the superconductor is of type I or type II. We illustrate\npreliminary results of a lattice determination of $\\xi$ for the case of pure\nYang-Mills with two colors, obtained by measuring the temporal correlator of a\ndisorder parameter detecting dual superconductivity."
    },
    {
        "anchor": "Non-perturbative determination of improvement coefficients using\n  coordinate space correlators in $N_f=2+1$ lattice QCD: We determine quark mass dependent order $a$ improvement terms of the form\n$b_J am$ for non-singlet scalar, pseudoscalar, vector and axialvector currents,\nusing correlators in coordinate space. We use a set of CLS ensembles comprising\nnon-perturbatively improved Wilson Fermions and the tree-level Luescher-Weisz\ngauge action at $\\beta=3.4,3.46,3.55$ and $\\beta=3.7$, corresponding to lattice\nspacings $a$ ranging from $0.05$ fm to $0.09$ fm. We report the values of the\n$b_J$ improvement coefficients which are proportional to non-singlet quark mass\ncombinations and also discuss the possibility of determining the $\\bar{b}_J$\ncoefficients which are proportional to the trace of the quark mass matrix.",
        "positive": "Persistent homology analysis for dense QCD effective model with heavy\n  quarks: The isospin chemical potential region is known as the sign-problem free\nregion of quantum chromodynamics (QCD). In this paper, we introduce the isospin\nchemical potential to the three-dimensional three-state Potts model to mimic\nthe dense QCD; e.g., the QCD effective model with heavy quarks at finite\ndensity. We call it as QCD-like Potts model. The QCD-like Potts model does not\nhave the sign problem, but we can expect that it shares some properties with\nQCD. Since we can obtain the non-approximated Potts spin configuration at\nfinite isospin chemical potential where the simple Metropolis algorithm can\nwork, we perform the persistent homology analysis towards exploring the dense\nspatial structure of QCD. We show that the averaged birth-death ratio has the\nsame information with the Polyakov loop, but the maximum birth-death ratio has\nadditional information near the phase transition."
    },
    {
        "anchor": "The XY Model Coupled to Two-Dimensional Quantum Gravity: We perform Monte Carlo simulations using the Wolff cluster algorithm of the\nXY model on both fixed and dynamical phi-cubed graphs (i.e. without and with\ncoupling to two-dimensional quantum gravity). We compare the numerical results\nwith the theoretical expectation that the phase transition remains of KT type\nwhen the XY model is coupled to gravity. We also examine whether the\nuniversality we discovered in our earlier work on various Potts models with the\nsame value of the central charge, $c$, carries over to the XY model, which has\n$c=1$.",
        "positive": "Heavy-light mesons with domain wall fermions: We present RBC heavy-light meson spectroscopy with quenched DBW2 gauge\nconfigurations at lattice cutoff of about 3 GeV. Both heavy and light quarks\nare described by domain-wall fermions (DWF). The heavy quark mass ranges\nbetween 0.1 and 0.4 lattice units, covering charm. The light quark mass ranges\nbetween 0.008 and 0.04, covering strange. In particular, we discuss charmed (D\nand D*) and charm-strange (Ds and DsJ) mesons with spin-parity JP= 0+/- and\n1+/-. The preliminary results indicate that DWF describe charm on the quenched\nDBW2 ensemble at this cutoff. The masses of the JP=0+/- and 1+/- D, D*, Ds and\nDsJ meson states are well reproduced to within a few %; their parity splitting,\nDeltaJ, are better reproduced than previous works, with only 10-20 % over\nestimations; the experimental observation that the splitting for non-strange\nstates is bigger than that for strange states is reproduced as well; but the\nhyperfine splittings are only 60-65 % reproduced. Regarding the depenence on\nheavy quark mass, J=0 and J=1 parity splittings are degenerate for heavy quark\nmass heavier than 0.2-0.3 lattice units a; the J=0 parity splitting increases\nas the heavy quark mass decreases further while the J=1 splitting does not."
    },
    {
        "anchor": "Conformal Theories with an IR cutoff: We give a new perspective on the dynamics of conformal theories realized in\nthe SU(N) gauge theory, when the number of flavors N_f is within the conformal\nwindow. Motivated by the RG argument on conformal theories with a finite IR\ncutoff \\Lambda_{IR}, we conjecture that the propagator of a meson G_H(t) on a\nlattice behaves at large t as a power-law corrected Yukawa-type decaying form\nG_H(t) = c_H \\exp{(-m_H t)}/t^{\\alpha_H} instead of the exponentially decaying\nform c_H\\exp{(-m_H t)}, in the small quark mass region where m_H \\le c\n\\Lambda_{IR}: m_H is the mass of the ground state hadron in the channel H and c\nis a constant of order 1. The transition between the \"conformal region\" and the\n\"confining region\" is a first order transition. Our numerical results verify\nthe predictions for the N_f=7 case and the N_f=16 case in the SU(3) gauge\ntheory with the fundamental representation.",
        "positive": "B semileptonic decays with 2+1 dynamical quark flavors: We study semileptonic B decays, using MILC dynamical configurations with\n$N_f=2+1$. NRQCD heavy and AsqTad light quark actions are used. We obtain the\nsemileptonic form factors $f_+(q^2)$ and $f_0(q^2)$ in the chiral limit."
    },
    {
        "anchor": "Renormalization constants for 2-twist operators in twisted mass QCD: Perturbative and non-perturbative results on the renormalization constants of\nthe fermion field and the twist-2 fermion bilinears are presented with emphasis\non the non-perturbative evaluation of the one-derivative twist-2 vector and\naxial vector operators. Non-perturbative results are obtained using the twisted\nmass Wilson fermion formulation employing two degenerate dynamical quarks and\nthe tree-level Symanzik improved gluon action. The simulations have been\nperformed for pion masses in the range of about 450-260 MeV and at three values\nof the lattice spacing $a$ corresponding to $\\beta=3.9, 4.05, 4.20$.\nSubtraction of ${\\cal O}(a^2)$ terms is carried out by performing the\nperturbative evaluation of these operators at 1-loop and up to ${\\cal O}(a^2)$.\nThe renormalization conditions are defined in the RI$'$-MOM scheme, for both\nperturbative and non-perturbative results. The renormalization factors,\nobtained for different values of the renormalization scale, are evolved\nperturbatively to a reference scale set by the inverse of the lattice spacing.\nIn addition, they are translated to ${\\bar{\\rm MS}}$ at 2 GeV using 3-loop\nperturbative results for the conversion factors.",
        "positive": "Confinement in $QCD$: novelties: We report on recent progress in understanding confinement of colour in $QCD$\nas dual superconductivity of the vacuum. A gauge invariant version of the\ncreation operator of monopoles is constructed whose vacuum expectation value is\nthe order parameter. This order parameter is gauge-invariant from scratch, has\nno infrared divergences, is finite in the confined phase and vanishes in the\ndeconfined phase. A natural explanation also emerges of why the electric field\nlines in the flux tubes keep no memory of the colour orientation of the\ncondensing monopoles. A further by-product is that the order parameter can be\ntraded with the two-point vacuum parallel correlator of the chromo-electric\nfield."
    },
    {
        "anchor": "Freeze-out parameters: lattice meets experiment: We present our results for ratios of higher order fluctuations of electric\ncharge as functions of the temperature. These results are obtained in a system\nof 2+1 quark flavors at physical quark masses and continuum extrapolated. We\ncompare them to preliminary data on higher order moments of the net electric\ncharge distribution from the STAR collaboration. This allows us to determine\nthe freeze-out temperature and chemical potential from first principles. We\nalso show continuum-extrapolated results for ratios of higher order\nfluctuations of baryon number. These will allow to test the consistency of the\napproach, by comparing them to the corresponding experimental data (once they\nbecome available) and thus extracting the freeze-out parameters in an\nindependent way.",
        "positive": "Follow-up on non-leptonic kaon decays at large $N_c$: We report on the status of our dynamical simulations of a $SU (N_c )$ gauge\ntheory with $N_c=3-6$ and $N_f =4$ fundamental fermions. These ensembles can be\nused to study the Large $N_c$ scaling of weak matrix elements in the GIM limit\n$m_c=m_u$, that might shed some light on the origin of the $\\Delta I=1/2$ rule.\nWe present preliminary results for the $K \\to \\pi$ matrix elements in the\n$N_c=3$ dynamical simulations, where we observe a significant effect of the\nquark loops that goes in the direction of enhancing the ratio of $A_0/A_2$\namplitudes. Finally, we present the relevant NLO Chiral Perturbation Theory\npredictions for the relation between $K \\to \\pi $ and $K \\to \\pi \\pi$\namplitudes in the light charm limit."
    },
    {
        "anchor": "Testing a generalized cooling procedure in the complex Langevin\n  simulation of chiral Random Matrix Theory: The complex Langevin method has been attracting much attention as a solution\nto the sign problem since the method was shown to work in finite density QCD in\nthe deconfined phase by using the so-called gauge cooling procedure. Whether it\nworks also in the confined phase with light quarks is still an open question,\nthough. In order to shed light on this question, we apply the method to the\nchiral Random Matrix Theory, which describes the epsilon regime of finite\ndensity QCD. Earlier works reported that a naive implementation of the method\nfails to reproduce the known exact results and that the problem can be solved\nby choosing a suitable coordinate. In this work we stick to the naive\nimplementation, and show that a generalized gauge cooling procedure can be used\nto avoid the problem.",
        "positive": "Unquenched determination of the kaon parameter B_K from improved\n  staggered fermions: The use of improved staggered actions (HYP, Asqtad) has been proved to reduce\nthe scaling corrections that affected previous calculations of B_K with\nunimproved (standard) staggered fermions in the quenched approximation. This\nimproved behaviour allows us to perform a reliable calculation of B_K including\nquark vacuum polarization effects, using the MILC configurations with n_f=2+1\nflavours of sea fermions. We perform such a calculation for a single lattice\nspacing, a=0.125 fm, and with kaons made up of degenerate quarks with m_s/2.\nThe valence strange quark mass m_s is fixed to its physical value and we use\ntwo different values of the light sea quark masses. After a chiral\nextrapolation of the results to the physical value of the sea quark masses, we\nfind \\hat B_K = 0.83+-0.18, where the error is dominated by the uncertainty in\nthe lattice to continuum matching at O(\\alpha_s^2). The matching will need to\nbe improved to get the precision needed to make full use of the experimental\ndata on \\epsilon_K to constrain the unitarity triangle."
    },
    {
        "anchor": "Classical Limits of Scalar and Tensor Gauge Operators Based on the\n  Overlap Dirac Matrix: It was recently proposed by the second author to consider lattice\nformulations of QCD in which complete actions, including the gauge part, are\nbuilt explicitly from a given Dirac operator D. In a simple example of such\ntheory, the gauge action is proportional to the trace of Ginsparg-Wilson\noperator D chosen to define the quark dynamics. This construction relies on the\nproposition that the classical limit of lattice gauge operator tr D(x,x) is\nproportional to tr F.F(x) (up to an additive constant). Here we show this for\nthe case of the overlap Dirac operator using both analytical and numerical\nmethods. We carry out the same analysis also for the tensor component of D,\nwhich is similarly related to the field-strength tensor F, and obtain results\nidentical to our previous derivation that used different approach. The\ncorresponding proportionality constants are computed to high precision for wide\nrange of the negative mass parameter values, and it is verified that they are\nthe same in finite and infinite volumes.",
        "positive": "The QCD Phase Transition Region with Domain Wall Quarks: Results will be presented from a study of the QCD transition region using 2+1\nflavors of fermions and a dislocation suppressing gauge action on a lattice\nwith temporal extent of 8 and spatial extent 16 (1.9 - 2.7 fm). A series of\ntemperatures from 140 through 200 MeV, separated by 10 MeV have been studied.\nAll the simulations lie on a line of constant physics with 200 MeV pions,\nrealized using domain wall fermion, a chirally symmetric fermion formulation.\nThe chiral condensates, susceptibility, anomalous symmetry breaking and a\ndetailed study of the Dirac spectrum will be described and compared with\nearlier staggered results."
    },
    {
        "anchor": "Meson masses at large N_c: We analyze the meson spectrum in SU(N_c) lattice gauge theory. We use Wilson\nquarks to measure the pseudoscalar and vector masses in SU(2), SU(3), SU(4) and\nSU(6), and extrapolate to the large-N_c limit. We find that finite-N_c\ncorrections are small at all values of the quark mass.",
        "positive": "Comparison with model-independent and dependent analyses for pion charge\n  radius: Traditionally, there has been a method to extract the charge radius of a\nhadron based on the fits of its form factor with some model assumptions. In\ncontrast, a completely different method has been proposed, which does not\ndepend on the models. In this report, we explore several improvements to this\nmodel-independent method for analyzing the pion charge radius. Furthermore, we\ncompare the results of the pion charge radius obtained from $N_{f}=2+1$ lattice\nQCD data at $m_{\\pi}=0.51$ GeV using the three different methods: the\ntraditional model-dependent method, the original model-independent method, and\nour improved model-independent method. In this comparison, we take into account\nsystematic errors estimated in each analysis."
    },
    {
        "anchor": "Excited hadrons on the lattice: Mesons: We present results for masses of excited mesons from quenched calculations\nusing chirally improved quarks at pion masses down to 350 MeV. The key features\nof our analysis are the use of a matrix of correlators from various source and\nsink operators and a basis which includes quark sources with different spatial\nwidths, thereby improving overlap with states exhibiting radial excitations.",
        "positive": "Anisotropic pressure induced by finite-size effects in SU(3) Yang-Mills\n  theory: We study the pressure anisotropy in anisotropic finite-size systems in SU(3)\nYang-Mills theory at nonzero temperature. Lattice simulations are performed on\nlattices with anisotropic spatial volumes with periodic boundary conditions.\nThe energy-momentum tensor defined through the gradient flow is used for the\nanalysis of the stress tensor on the lattice. We find that a clear finite-size\neffect in the pressure anisotropy is observed only at a significantly shorter\nspatial extent compared with the free scalar theory, even when accounting for a\nrather large mass in the latter."
    },
    {
        "anchor": "The Static Quark-Antiquark Potential: A ``Classical'' Experiment On The\n  Connection Machine CM-2: We describe the Wuppertal university pilot project in applied parallel\ncomputing. We report on a comprehensive high statistics determination of the\nstatic quark-antiquark potential and related quantities from quenched quantum\nchromodynamics. New data for the string tension and the plaquette action for\nthe region 5.5 < beta < 6.8 is presented.",
        "positive": "Implementing noise reduction techniques into theOpenQ*D package: We present the results of testing a new technique for stochastic noise\nreduction in the calculation of propagators by implementing it in OpenQ*D for\ntwo ensembles with O(a) improved Wilson fermion action, with periodic boundary\nconditions and pion masses of 437 MeV and 331 MeV, for the connected vector and\npseudoscalar correlators. We find that the technique yields no speedup compared\nto traditional methods, owning to the failure of its underlying assumption that\nthe spectra of the spatial Laplacian and Dirac operators are sufficiently\nsimilar for the technique's purposes."
    },
    {
        "anchor": "A lattice study of N=2 Landau-Ginzburg model using a Nicolai map: It has been conjectured that the two-dimensional N=2 Wess-Zumino model with a\nquasi-homogeneous superpotential provides the Landau-Ginzburg description of\nthe N=2 superconformal minimal models. For the cubic superpotential W=(lambda)\nPhi^3/3, it is expected that the Wess-Zumino model describes A_{2} model and\nthe chiral superfield Phi shows the conformal weight (h,bar{h})=(1/6,1/6) at\nthe IR fixed point. We study this conjecture by a lattice simulation,\nextracting the weight from the finite volume scaling of the susceptibility of\nthe scalar component in Phi. We adopt a lattice model with the overlap fermion,\nwhich possesses a Nicolai map and a discrete R-symmetry. We set a(lambda)=0.3\nand generate the scalar field configurations by solving the Nicolai map on L\ntimes L lattices in the range L=18 - 32. To solve the map, we use the\nNewton-Raphson algorithm with various initial configurations. The result is\n1-h-bar{h}=0.660 \\pm0.011, which is consistent with the conjecture within the\nstatistical error, while a systematic error is estimated as less than 0.5 %.",
        "positive": "Monte Carlo simulation of SU(2) Yang-Mills theory with light gluinos: In a numerical Monte Carlo simulation of SU(2) Yang-Mills theory with light\ndynamical gluinos the low energy features of the dynamics as confinement and\nbound state mass spectrum are investigated. The motivation is supersymmetry at\nvanishing gluino mass. The performance of the applied two-step multi-bosonic\ndynamical fermion algorithm is discussed."
    },
    {
        "anchor": "The Second Moment of the Pion Light Cone Wave Function: We present a preliminary result for second moment of the light cone wave\nfunction of the pion. This parameter is the subject of a discrepancy between\ntheoretical predictions (coming from lattice and sum rules) and a recent\nexperimental result (that remarkably agrees with purely perturbative\npredictions). In this work we exploit lattice hypercubic symmetries to remove\npower divergences and, moreover, implement a full 1-loop matching for all the\ncontributing operators.",
        "positive": "Scalar glueball and meson spectroscopy in unquenched lattice QCD with\n  improved staggered quarks: We present results of an exploratory study of singlet scalar states in\nunquenched QCD using both glueball and meson operators. Results for non-singlet\nnon-strange scalar mesons are also presented. We use Asqtad improved staggered\nfermions and gauge configurations generated by the MILC collaboration at\nlattice spacings of .12 and .09 fm. In this formulation, the glueball mass is\nnot significantly different from the quenched value at finite lattice spacing.\nSignificant taste violations are present in the scalar sector. At light quark\nmasses, decay channels complicate the mass determinations. There is some\nevidence that the non-strange singlet meson lies below the non-singlet meson."
    },
    {
        "anchor": "The topological structure of SU(2) gluodynamics at T > 0 : an analysis\n  using the Symanzik action and Neuberger overlap fermions: We study SU(2) gluodynamics at finite temperature on both sides of the\ndeconfining phase transition. We create the lattice ensembles using the\ntree-level tadpole-improved Symanzik action. The Neuberger overlap Dirac\noperator is used to determine the following three aspects of vacuum structure:\n(i) The topological susceptibility is evaluated at various temperatures across\nthe phase transition, (ii) the overlap fermion spectral density is determined\nand found to depend on the Polyakov loop above the phase transition and (iii)\nthe corresponding localization properties of low-lying eigenmodes are\ninvestigated. Finally, we compare with zero temperature results.",
        "positive": "Monte-Carlo simulation of the tight-binding model of graphene with\n  partially screened Coulomb interactions: We report on Hybrid-Monte-Carlo simulations of the tight-binding model with\nlong-range Coulomb interactions for the electronic properties of graphene. We\ninvestigate the spontaneous breaking of sublattice symmetry corresponding to a\ntransition from the semimetal to an antiferromagnetic insulating phase. Our\nshort-range interactions thereby include the partial screening due to electrons\nin higher energy states from ab initio calculations based on the constrained\nrandom phase approximation [T.O.Wehling {\\it et al.}, Phys.Rev.Lett.{\\bf 106},\n236805 (2011)]. In contrast to a similar previous Monte-Carlo study\n[M.V.Ulybyshev {\\it et al.}, Phys.Rev.Lett.{\\bf 111}, 056801 (2013)] we also\ninclude a phenomenological model which describes the transition to the\nunscreened bare Coulomb interactions of graphene at half filling in the\nlong-wavelength limit. Our results show, however, that the critical coupling\nfor the antiferromagnetic Mott transition is largely insensitive to the\nstrength of these long-range Coulomb tails. They hence confirm the prediction\nthat suspended graphene remains in the semimetal phase when a realistic static\nscreening of the Coulomb interactions is included."
    },
    {
        "anchor": "Exact Lattice Supersymmetry at the Quantum Level for $N=2$ Wess-Zumino\n  Models in 1- and 2-Dimensions: Supersymmetric lattice Ward-Takahashi identities are investigated\nperturbatively up to two-loop corrections for super doubler approach of $N=2$\nlattice Wess-Zumino models in 1- and 2-dimensions. In this approach notorious\nchiral fermion doublers are treated as physical particles and momentum\nconservation is modified in such a way that lattice Leibniz rule is satisfied.\nThe two major difficulties to keep exact lattice supersymmetry are overcome.\nThis formulation defines, however, nonlocal field theory. Nevertheless we\nconfirm that exact supersymmetry on the lattice is realized for all\nsupercharges at the quantum level. Delicate issues of associativity are also\ndiscussed.",
        "positive": "Progress report on hadron spectroscopy with improved actions: Quenched light hadron masses are measured on blocked lattices, using 6\ndifferent lattice discretizations of the Dirac operator. Results are compared\nwith those of unblocked lattices, allowing for a ``ranking'' of the Dirac\ndiscretizations."
    },
    {
        "anchor": "The phase structure of a chirally-invariant Higgs-Yukawa model: We present new results of our ongoing project on the investigation of the\nphase structure of the Higgs-Yukawa model at small and large bare Yukawa\ncouplings. The critical exponents of the second order bulk phase transitions of\nthis model are determined from finite-size analyses and compared to the pure\nO(4)-model to test for triviality and the possibility of having a non-Gaussian\nfixed point. In addition, we will present a first study of Higgs boson masses\nand fermion correlation functions.",
        "positive": "Study of H-dibaryon mass in Lattice QCD: After a brief review of discovery of the H-dibaryon in lattice QCD, effect of\nthe flavor SU(3) symmetry breaking on the H-dibaryon is studied by basing on\nthe baryon-baryon (BB) interactions extracted from QCD on the lattice. The\nSchrodinger equation for Lambda Lambda - N Xi -Sigma Sigma coupled-channel is\nsolved with the physical baryon masses and the potentials obtained from QCD at\nthe flavor SU(3) limit. A resonant H-dibaryon is found between Lambda Lambda\nand N Xi thresholds in this treatment."
    },
    {
        "anchor": "The $I$ = 1/2 and 3/2 $K-\u03c0$ scattering length with domain wall\n  fermions at physical pion mass with all-to-all propagators: We present our calculations for the $I$ = 1/2 and 3/2 $K-\\pi$ s-wave\nscattering length with physical quark masses, extracted from the interaction\nenergy of Euclidean two-point functions. We use the domain wall fermion action\nwith physical quark masses at a single lattice spacing. We are specifically\ninterested in the systematic effects due to around-the-world terms on the\noverall determination of the scattering length. We present our progress and\ndiscuss the various systematic effects in our preliminary results.",
        "positive": "Reconstruction of smeared spectral function from Euclidean correlation\n  functions: We propose a method to reconstruct smeared spectral functions from two-point\ncorrelation functions measured on the Euclidean lattice. Arbitrary smearing\nfunction can be considered as far as it is smooth enough to allow an\napproximation using Chebyshev polynomials. We test the method with numerical\nlattice data of Charmonium correlators. The method provides a framework to\ncompare lattice calculation with experimental data including excited state\ncontributions without assuming quark-hadron duality."
    },
    {
        "anchor": "A Connection Between Complex-Temperature Properties of the 1D and 2D\n  Spin $s$ Ising Model: Although the physical properties of the 2D and 1D Ising models are quite\ndifferent, we point out an interesting connection between their\ncomplex-temperature phase diagrams. We carry out an exact determination of the\ncomplex-temperature phase diagram for the 1D Ising model for arbitrary spin $s$\nand show that in the $u_s=e^{-K/s^2}$ plane (i) it consists of $N_{c,1D}=4s^2$\ninfinite regions separated by an equal number of boundary curves where the free\nenergy is non-analytic; (ii) these curves extend from the origin to complex\ninfinity, and in both limits are oriented along the angles $\\theta_n =\n(1+2n)\\pi/(4s^2)$, for $n=0,..., 4s^2-1$; (iii) of these curves, there are\n$N_{c,NE,1D}=N_{c,NW,1D}=[s^2]$ in the first and second (NE and NW) quadrants;\nand (iv) there is a boundary curve (line) along the negative real $u_s$ axis if\nand only if $s$ is half-integral. We note a close relation between these\nresults and the number of arcs of zeros protruding into the FM phase in our\nrecent calculation of partition function zeros for the 2D spin $s$ Ising model.",
        "positive": "Light hadron spectrum and quark masses in 2+1 flavor QCD: CP-PACS and JLQCD collaborations are carrying out a joint project of the 2+1\nflavor full QCD simulation. Gauge configurations are generated for the\nnon-perturbatively $O(a)$-improved Wilson quark action and the Iwasaki gauge\naction using PHMC algorithm at three lattice spacings, $a\\sim 0.076$, 0.010 and\n0.122 fm, with a fixed physical volume $(2.0 fm)^3$. We present analysis for\nthe light meson spectrum and quark masses in the continuum limit, which are\ndetermined using data obtained from the simulations at the two coarser\nlattices. Our simulations reproduce experimental values of meson masses. The ud\nand strange quark masses turn out to be $m_{ud}^{\\bar{MS}}(\\mu=2 GeV)=3.34(23)\nMeV$ and $m_s^{\\bar{MS}}(\\mu=2 GeV)=86.7(5.9) MeV$. We also show preliminary\nresults at our finest lattice spacing for which simulations are still being\ncontinued."
    },
    {
        "anchor": "Influence of Fermions on Vortices in SU(2)-QCD: Gauge fields control the dynamics of fermions, also a back reaction of\nfermions on the gauge field is expected. This back reaction is investigated\nwithin the vortex picture of the QCD vacuum. We show that the center vortex\nmodel reproduces the string tension of the full theory also with the presence\nof fermionic fields.",
        "positive": "Exploring SU(3)-Higgs theories: The requirement of manifest gauge invariance leads to a conflict between\nperturbative and non-perturbative predictions for the low-energy spectra of\ngrand-unified theories. These conflicts already emerge in simplified prototype\nmodels of SU(3) gauge theories with Higgs fields in different representations.\nWe expand earlier lattice investigations on this subject and provide further\nsupport for the predicted deviations. These can be understood in terms of the\nFroehlich-Morchio-Strocchi mechanism."
    },
    {
        "anchor": "Calculations of hadronic matrix elements using lattice qcd: I give a brief introduction to the scope of lattice QCD calculations in our\neffort to extract the fundamental parameters of the standard model. This goal\nis illustrated by two examples. First I discuss the extraction of CKM matrix\nelements from measurements of form factors for semi-leptonic decays of\nheavy-light pseudoscalar mesons such as $D \\to Ke\\nu$. Second, I present the\nstatus of results for the kaon $B$ parameter relevant to CP violation. I\nconclude the talk with a short outline of our experiences with optimizing QCD\ncodes on the CM5.",
        "positive": "The phase boundary for the chiral transition in (2+1)-flavor QCD at\n  small values of the chemical potential: We determine the chiral phase transition line in (2+1)-flavor QCD for small\nvalues of the light quark chemical potential. We show that for small values of\nthe chemical potential the curvature of the phase transition line can be\ndeduced from an analysis of scaling properties of the chiral condensate and its\nsusceptibilities. To do so we extend earlier studies of the magnetic equation\nof state in (2+1)-flavor QCD to finer lattice spacings, aT=1/8. We use these\nuniversal scaling properties of the chiral order parameter to extract the\ncurvature of the transition line at two values of the cut-off, aT=1/4 and 1/8.\nWe find that cut-off effects are small for the curvature parameter and\ndetermine the transition line in the chiral limit to leading order in the light\nquark chemical potential. We obtain Tc(\\mu_q)/Tc(0) = 1 - 0.059(2)(4)\n(\\mu_q/T)^2 +O(\\mu_q^4)."
    },
    {
        "anchor": "Non-perturbative renormalization of O(a) improved tensor currents: We present our progress in the non-perturbative O(a) improvement and\nrenormalization of tensor currents in three-flavor lattice QCD with\nWilson-clover fermions and tree-level Symanzik improved gauge action. The\nmass-independent O(a) improvement factor of tensor currents is determined via a\nWard identity approach, and their renormalization group running is calculated\nvia recursive finite-size scaling techniques, both implemented within the\nSchr\\\"odinger functional framework. We also address the matching factor between\nbare and renormalization group invariant currents for a range of lattice\nspacings < 0.1 fm, relevant for phenomenological large-volume lattice QCD\napplications.",
        "positive": "Remarks about weighted energy integrals over Minkowski spectral\n  functions from Euclidean lattice data: I make some simple observations about the calculation of weighted averages\nover energy of Minkowski space spectral densities from weighted averages over\ntime of Euclidean space correlation functions, measured in latice simulations.\nThe correlator of two vector currents is used as an example, where it appears\nthat a determination of a weighted average of the spectral function near the\nrho pole at the five per cent level is possible from lattice simulations."
    },
    {
        "anchor": "Low-lying Eigenvalues of the improved Wilson-Dirac Operator in QCD: The spectral flow of the low-lying eigenvalues of the improved and unimproved\nWilson-Dirac operator is studied on instanton-like configurations and on\nthermalized quenched configurations at various $\\beta$-values and lattice\nsizes. We also investigate the space-time localisation and chirality of the\ncorresponding eigenvectors.",
        "positive": "Quarks, Gluons and Frustrated Antiferromagnets: The Contractor Renormalization Group method (CORE) is used to establish the\nequivalence of various Hamiltonian free fermion theories and a class of\ngeneralized frustrated antiferromagnets. In particular, after a detailed\ndiscussion of a simple example, it is argued that a generalized frustrated\nSU(3) antiferromagnet whose single-site states have the quantum numbers of\nmesons and baryons is equivalent to a theory of free massless quarks.\nFurthermore, it is argued that for slight modification of the couplings which\ndefine the frustrated antiferromagnet Hamiltonian, the theory becomes a theory\nof quarks interacting with color gauge-fields."
    },
    {
        "anchor": "Spectrum of the Dirac operator coupled to two-dimensional quantum\n  gravity: We implement fermions on dynamical random triangulation and determine\nnumerically the spectrum of the Dirac-Wilson operator D for the system of\nMajorana fermions coupled to two-dimensional Euclidean quantum gravity. We\nstudy the dependence of the spectrum of the operator (epsilon D) on the hopping\nparameter. We find that the distributions of the lowest eigenvalues become\ndiscrete when the hopping parameter approaches the value 1/sqrt{3}. We show\nthat this phenomenon is related to the behavior of the system in the\n'antiferromagnetic' phase of the corresponding Ising model. Using finite size\nanalysis we determine critical exponents controlling the scaling of the lowest\neigenvalue of the spectrum including the Hausdorff dimension d_H and the\nexponent kappa which tells us how fast the pseudo-critical value of the hopping\nparameter approaches its infinite volume limit.",
        "positive": "Report of the Snowmass 2013 Computing Frontier working group on Lattice\n  Field Theory -- Lattice field theory for the energy and intensity frontiers:\n  Scientific goals and computing needs: This is the report of the Computing Frontier working group on Lattice Field\nTheory prepared for the proceedings of the 2013 Community Summer Study\n(\"Snowmass\"). We present the future computing needs and plans of the U.S.\nlattice gauge theory community and argue that continued support of the U.S.\n(and worldwide) lattice-QCD effort is essential to fully capitalize on the\nenormous investment in the high-energy physics experimental program. We first\nsummarize the dramatic progress of numerical lattice-QCD simulations in the\npast decade, with some emphasis on calculations carried out under the auspices\nof the U.S. Lattice-QCD Collaboration, and describe a broad program of\nlattice-QCD calculations that will be relevant for future experiments at the\nintensity and energy frontiers. We then present details of the computational\nhardware and software resources needed to undertake these calculations."
    },
    {
        "anchor": "SU(3) Flavor Breaking in Hadronic Matrix Elements for $B - \\bar B$\n  Oscillations: We present an analysis, using quenched configurations at $6/g^2=$5.7, 5.85,\n6.0, and 6.3 of the matrix element $\\MP\\equiv\\langle \\bar P_{hl}|\\bar h\n\\gamma_\\mu (1-\\gamma_5)l \\bar h \\gamma_\\mu(1-\\gamma_5)l|P_{hl}\\rangle$ for\nheavy-light pseudoscalar mesons. The results are extrapolated to the physical\n$B$ meson states, $\\Bd$ and $\\Bs$. We directly compute the ratio $\\MS/\\MB$, and\nobtain the preliminary result $\\MS/\\MB=1.54(13)(32)$. A precise value of this\nSU(3) breaking ratio is important for determining $V_{td}$ once the mixing\nparameter $x_s$ for $\\Bs-\\bar\\Bs$ is measured experimentally. We also determine\nvalues for the corresponding B parameters, $B_{bs}(2 \\rm{GeV})=B_{bd}(2\n\\rm{GeV})=1.02(13)$, which we cannot distinguish in the present analysis.",
        "positive": "A comparative study of numerical methods for the overlap Dirac\n  operator--a status report: Improvements of various methods to compute the sign function of the hermitian\nWilson-Dirac matrix within the overlap operator are presented. An optimal\npartial fraction expansion (PFE) based on a theorem of Zolotarev is given.\nBenchmarks show that this PFE together with removal of converged systems within\na multi-shift CG appears to approximate the sign function times a vector most\nefficiently. A posteriori error bounds are given."
    },
    {
        "anchor": "Computing Nucleon Electric Dipole Moment from lattice QCD: Electric dipole moments (EDMs) of nucleons and nuclei are actively considered\nas direct evidence of the CP violation. Calculations of nucleon EDMs on lattice\nare required to connect the quark- and hadron- level effective CP violating\ninteractions within QCD or other CP violating sources in new physics beyond the\nstandard model. Among them, the theta-induced nucleon EDM, that is the only\nsuch renormalizable interaction, has widely been investigated on a lattice. In\nthe report, we review recent developments of the lattice calculations of\nnucleon EDM induced QCD theta term.",
        "positive": "Theoretical Foundation of the Nuclear Force in QCD and its applications\n  to Central and Tensor Forces in Quenched Lattice QCD Simulations: We present full accounts of a method to extract nucleon-nucleon (NN)\npotentials from the Bethe-Salpter amplitude in lattice QCD. The method is\napplied to two nucleons on the lattice with quenched QCD simulations. By\ndisentangling the mixing between the S-state and the D-state, we obtain central\nand tensor potentials in the leading order of the velocity expansion of the\nnon-local NN potential. The spatial structure and the quark mass dependence of\nthe potentials are analyzed in detail."
    },
    {
        "anchor": "Large $N$ simulation of the twisted reduced matrix model with an adjoint\n  Majorana fermion: To investigate the properties of the large $N$ limit of $\\mathcal{N} = 1$\nSUSY Yang-Mills theory, we have started a study for a reduced matrix model with\nan adjoint Majorana fermion. The gauge action is based on the Wilson action and\nthe adjoint-fermion one is the Wilson-Dirac action on a reduced lattice with\ntwisted gauge boundary condition. We employ the RHMC algorithm in which the\nabsolute value of the Pfaffian is incorporated. The sign of the Pfaffian is\nincluded with the re-weighting method and separately measured as an observable.\nIn this talk, we show the configuration generation status towards the large $N$\nlimit and the behavior of the lowest/lower eigenvalue(s) of the Wilson-Dirac\nadjoint fermion operator. We investigated the sign of the Pfaffian and the\ncritical hopping parameters for the chiral limit. The sign of the Pfaffian is\nalways positive on the configurations we have generated. The critical hopping\nparameters derived from the eigenvalues of the Dirac operator are consistent\nwith those derived from the PCAC mass relation with non-singlet flavor adjoint\nfermions.",
        "positive": "New Way to Resum the Lattice QCD Taylor Series Equation of State at\n  Finite Chemical Potential: Taylor expansion of the thermodynamic potential in powers of the\n(baryo)chemical potential $\\mu_B$ is a well-known method to bypass the Sign\nProblem of Lattice QCD. Due to the difficulty in calculating the higher order\nTaylor coefficients, various alternative expansion schemes as well as\nresummation techniques have been suggested to extend the Taylor series to\nlarger values of $\\mu_B$. Recently, a way to resum the contribution of the\nfirst $N$ charge density correlation functions $D_1,\\dots,D_N$ to the Taylor\nseries to all orders in $\\mu_B$ was proposed in Phys. Rev. Lett. 128, 2, 022001\n(2022). The resummation takes the form of an exponential factor. Since the\ncorrelation functions are calculated stochastically, the exponential factor\ncontains a bias which can be significant for large $N$ and $\\mu_B$. In this\npaper, we present a new method to calculate the QCD equation of state based on\nthe well-known cumulant expansion from statistics. By truncating the expansion\nat a maximum order $M$, we end up with only finite products of the correlation\nfunctions which can be evaluated in an unbiased manner. Although our formalism\nis also applicable for $\\mu_B\\ne0$, here we present it for the simpler case of\na finite isospin chemical potential $\\mu_I$ for which there is no Sign Problem.\nWe present and compare results for the pressure and the isospin density\nobtained using Taylor expansion, exponential resummation and cumulant\nexpansion, and provide evidence that the absence of bias in the latter actually\nimproves the convergence."
    },
    {
        "anchor": "Electric conductivity in finite-density SU(2) lattice gauge theory with\n  dynamical fermions: We study the dependence of the electric conductivity on chemical potential in\nfinite-density $SU(2)$ gauge theory with $N_f = 2$ flavours of rooted staggered\nsea quarks, in combination with Wilson-Dirac and Domain Wall valence quarks.\nThe pion mass is reasonably small with $m_{\\pi}/m_{\\rho} \\approx 0.4$. We\nconcentrate in particular on the vicinity of the chiral crossover, where we\nfind the low-frequency electric conductivity to be most sensitive to small\nchanges in fermion density. Working in the low-density QCD-like regime with\nspontaneously broken chiral symmetry, we obtain an estimate of the first\nnontrivial coefficient $c(T)$ of the expansion of conductivity $\\sigma(T,\\mu) =\n\\sigma(T,0) \\left(1 + c(T) (\\mu/T)^2 + O(\\mu^4)\\right)$ in powers of $\\mu$,\nwhich has rather weak temperature dependence and takes its maximal value $c(T)\n\\approx 0.10 \\pm 0.07$ around the critical temperature. At larger densities and\nlower temperatures, the conductivity quickly grows towards the diquark\ncondensation phase, and also becomes closer to the free quark result. As a\nby-product of our study we confirm the conclusions of previous studies with\nheavier pion that for $SU(2)$ gauge theory the ratio of crossover temperature\nto pion mass $T_c/m_{\\pi} \\approx 0.4$ at $\\mu=0$ is significantly smaller than\nin real QCD.",
        "positive": "The author replies: I respond to the Bernard et al. comment on my letter ``Chiral anomalies and\nrooted staggered fermions.''"
    },
    {
        "anchor": "Scattering with real-time path integrals: Sharp-momentum transition matrix elements for scattering from a short-range\nGaussian potential are computed using a real-time path integral. The\ncomputation is based on a numerical implementation of a new interpretation of\nthe path integral as the expectation of a potential functional with respect to\na complex probability distribution on cylinder sets of paths. The method is\nclosely related to a unitary transfer matrix computation.",
        "positive": "Chiral symmetry breaking, instantons and the ultimate quenched\n  calculation: We calculate the spectral density of the Dirac operator over an ensemble of\nconfigurations composed of overlapping instantons and anti-instantons. We find\nevidence that the spectral density diverges in the limit of small eigenvalues.\nThis indicates the breaking of chiral symmetry and also provides evidence that\nquenched QCD may be pathological in nature."
    },
    {
        "anchor": "$B$- and $D$-meson leptonic decay constants from four-flavor lattice QCD: We calculate the leptonic decay constants of heavy-light pseudoscalar mesons\nwith charm and bottom quarks in lattice quantum chromodynamics on four-flavor\nQCD gauge-field configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We\nanalyze over twenty isospin-symmetric ensembles with six lattice spacings down\nto $a\\approx 0.03$~fm and several values of the light-quark mass down to the\nphysical value $\\frac{1}{2}(m_u+m_d)$. We employ the highly-improved\nstaggered-quark (HISQ) action for the sea and valence quarks; on the finest\nlattice spacings, discretization errors are sufficiently small that we can\ncalculate the $B$-meson decay constants with the HISQ action for the first time\ndirectly at the physical $b$-quark mass. We obtain the most precise\ndeterminations to-date of the $D$- and $B$-meson decay constants and their\nratios, $f_{D^+} = 212.7(0.6)$~MeV, $f_{D_s} = 249.9(0.4)$~MeV,\n$f_{D_s}/f_{D^+} = 1.1749(16)$, $f_{B^+} = 189.4 (1.4)$~MeV, $f_{B_s} =\n230.7(1.3)$~MeV, $f_{B_s}/f_{B^+} = 1.2180(47)$, where the errors include\nstatistical and all systematic uncertainties. Our results for the $B$-meson\ndecay constants are three times more precise than the previous best lattice-QCD\ncalculations, and bring the QCD errors in the Standard-Model predictions for\nthe rare leptonic decays $\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 3.64(11)\n\\times 10^{-9}$, $\\overline{\\mathcal{B}}(B^0 \\to \\mu^+\\mu^-) = 1.00(3) \\times\n10^{-10}$, and $\\overline{\\mathcal{B}}(B^0 \\to\n\\mu^+\\mu^-)/\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 0.0273(9)$ to well\nbelow other sources of uncertainty. As a byproduct of our analysis, we also\nupdate our previously published results for the light-quark-mass ratios and the\nscale-setting quantities $f_{p4s}$, $M_{p4s}$, and $R_{p4s}$. We obtain the\nmost precise lattice-QCD determination to date of the ratio $f_{K^+}/f_{\\pi^+}\n= 1.1950(^{+16}_{-23})$~MeV.",
        "positive": "A New Approach of Fermion Field on Lattice: A new approach to formulate the fermion field on lattice is introduced by\nproposing a new Dirac operator on lattice.This approach can eliminate the\nFermion doubling problem, preserve the chiral symmetry and get the same\ndispersion relation for both Fermion and Boson fields.Then the Weinberg-Salam\nmodel on lattice may be formulated in this approach."
    },
    {
        "anchor": "Universal properties of the confining string in the random percolation\n  model: Random percolation can be fully interpreted as a confining pure gauge theory.\nWith numerical high-precision measurements of Polyakov-Polyakov correlators at\nfinite temperature, we could well observe the presence of shape effects due to\nrough fluctuations of the confining string, in complete agreement with the\nuniversality predictions up to the next-to-leading order.",
        "positive": "Beyond Complex Langevin Equations: a Progress Report: After a short review of one of proposals to avoid complex stochastic\nprocesses in Complex Langevin studies, the recent progress in the former is\nreported. In particular, the new developments allow now to construct positive\nand normalizable representations for gaussian quantum mechanical, as well as\nfield theoretical, path integrals directly in the Minkowski time. A relation to\nthe idea of thimbles is also discussed."
    },
    {
        "anchor": "Light baryon masses with dynamical twisted mass fermions: We present results on the mass of the nucleon and the Delta using two\ndynamical degenerate twisted mass quarks and the tree-level Symanzik improved\ngauge action. The evaluation is performed at four quark masses corresponding to\na pion mass in the range of about 300-600 MeV on lattices of 2.1-2.7 fm. We\ncheck for cut-off effects by evaluating these baryon masses on lattices of\nspatial size 2.1 fm at beta=3.9 and beta=4.05 and on a lattice of 2.4 fm at\nbeta=3.8. The values we find are compatible within our statistical errors.\nLattice results are extrapolated to the physical limit using continuum chiral\nperturbation theory. Performing a combined fit to our lattice data at beta=3.9\nand beta=4.05 we find a nucleon mass of 964\\pm 28 (stat.) \\pm 8 (syst.) MeV.\nThe nucleon mass at the physical point provides an independent determination of\nthe lattice spacing. Using heavy baryon chiral perturbation theory at O(p^3) we\nfind a_{\\beta=3.9}=0.0890\\pm 0.0039(stat.) \\pm 0.0014(syst.) fm, and\na_{\\beta=4.05}= 0.0691\\pm 0.0034(stat.) \\pm 0.0010(syst.) fm, in good agreement\nwith the values determined from the pion decay constant. Isospin violating\nlattice artifacts in the Delta-system are found to be compatible with zero for\nthe values of the lattice spacings used in this work. Performing a combined fit\nto our lattice data at beta=3.9 and beta=4.05 we find for the masses of the\nDelta^{++,-} and Delta^{+,0} 1316 \\pm 60 (stat.) MeV and 1330 \\pm 74 (stat.)\nMeV respectively. We confirm that in the continuum limit they are also\ndegenerate.",
        "positive": "Four-Flavour Leading-Order Hadronic Contribution To The Muon Anomalous\n  Magnetic Moment: We present a four-flavour lattice calculation of the leading-order hadronic\nvacuum polarisation contribution to the anomalous magnetic moment of the muon,\n$a_\\mathrm{\\mu}^{\\rm hvp}$, arising from quark-connected Feynman graphs. It is\nbased on ensembles featuring $N_f=2+1+1$ dynamical twisted mass fermions\ngenerated by the European Twisted Mass Collaboration (ETMC). Several light\nquark masses are used in order to yield a controlled extrapolation to the\nphysical pion mass. We employ three lattice spacings to examine lattice\nartefacts and several different volumes to check for finite-size effects.\nIncorporating the complete first two generations of quarks allows for a direct\ncomparison with phenomenological determinations of $a_\\mathrm{\\mu}^{\\rm hvp}$.\nOur final result including an estimate of the systematic uncertainty\n$$a_{\\mathrm{\\mu}}^{\\rm hvp} = 6.74(21)(18) \\cdot 10^{-8}$$ shows a good\noverall agreement with these computations."
    },
    {
        "anchor": "String breaking with Wilson loops?: A convincing, uncontroversial observation of string breaking, when the static\npotential is extracted from Wilson loops only, is still missing. This failure\ncan be understood if the overlap of the Wilson loop with the broken string is\nexponentially small. In that case, the broken string ground state will only be\nseen if the Wilson loop is long enough. Our preliminary results show string\nbreaking in the context of the 3d SU(2) adjoint static potential, using the\nL\\\"uscher-Weisz exponential variance reduction approach. As a by-product, we\nmeasure the fundamental SU(2) static potential with improved accuracy and see\nclear deviations from Casimir scaling.",
        "positive": "Renormalization of Polyakov loops in fundamental and higher\n  representations: We compare two renormalization procedures, one based on the short distance\nbehavior of heavy quark-antiquark free energies and the other by using bare\nPolyakov loops at different temporal extent of the lattice and find that both\nprescriptions are equivalent, resulting in renormalization constants that\ndepend on the bare coupling. Furthermore these renormalization constants show\nCasimir scaling for higher representations of the Polyakov loops. The analysis\nof Polyakov loops in different representations of the color SU(3) group\nindicates that a simple perturbative inspired relation in terms of the\nquadratic Casimir operator is realized to a good approximation at temperatures\n$T \\gsim T_c$ for renormalized as well as bare loops. In contrast to a\nvanishing Polyakov loop in representations with non-zero triality in the\nconfined phase, the adjoint loops are small but non-zero even for temperatures\nbelow the critical one. The adjoint quark-antiquark pairs exhibit screening.\nThis behavior can be related to the binding energy of gluelump states."
    },
    {
        "anchor": "A multigrid implementation of the Fourier acceleration method for Landau\n  gauge fixing: We present a new implementation of the Fourier acceleration method for Landau\ngauge fixing. By means of a multigrid inversion we are able to avoid the use of\nthe fast Fourier transform. This makes the method more flexible, and well\nsuited for vector and parallel machines. We study the performance of this\nalgorithm on serial and on parallel (APE100) machines for the 4-dimensional\nSU(2) case. We find that our method is equivalent to the standard\nimplementation of Fourier acceleration already on a serial machine, and that it\nparallelizes very efficiently: its computational cost shows a linear speedup\nwith the number of processors. We have also implemented, on the parallel\nmachines, a version of the method using conjugate gradient instead of\nmultigrid. This leads to an algorithm that is efficient at intermediate lattice\nvolumes.",
        "positive": "Phase structure of twisted Eguchi-Kawai model: We study the phase structure of the four-dimensional twisted Eguchi-Kawai\nmodel using numerical simulations. This model is an effective tool for studying\nSU(N) gauge theory in the large-N limit and provides a nonperturbative\nformulation of the gauge theory on noncommutative spaces. Recently it was found\nthat its Z_N^4 symmetry, which is crucial for the validity of this model, can\nbreak spontaneously in the intermediate coupling region. We investigate in\ndetail the symmetry breaking point from the weak coupling side. Our simulation\nresults show that the continuum limit of this model cannot be taken."
    },
    {
        "anchor": "The Heavy Hybrid Spectrum from NRQCD and the Born-Oppenheimer\n  Approximation: The spectrum of heavy-quark hybrids is studied in the leading\nBorn-Oppenheimer (LBO) approximation and using leading-order NRQCD simulations\nwith an improved gluon action on anisotropic lattices. The masses of four\nhybrid states are obtained from our simulations for lattice spacings 0.1 fm and\n0.2 fm and are compared to the LBO predictions obtained using\npreviously-determined glue-excited static potentials. The consistency of\nresults from the two approaches reveals a compelling physical picture for\nheavy-quark hybrid states.",
        "positive": "Vortices and the SU(3) string tension: We present simulation results comparing the SU(3) heavy quark potential\nextracted from the full Wilson loop expectation to that extracted from the\nexpectation of the Wilson loop fluctuation solely by elements of Z(3). The two\npotentials are found to coincide. This agreement is stable under multiple\nsmoothings of the configurations which remove short distance fluctuations, and\nthus reflects long-distance physics. It strongly indicates that the asymptotic\nstring tension arises from thick center vortices linking with the Wilson loop."
    },
    {
        "anchor": "The confining string beyond the free-string approximation in the gauge\n  dual of percolation: We simulate five different systems belonging to the universality class of the\ngauge dual of three-dimensional random percolation to study the underlying\neffective string theory at finite temperature. All the data for the finite\ntemperature string tension, when expressed by means of adimensional variables,\nare nicely described by a unique scaling function. We calculate the first few\nterms of the string tension up to order $T^6$ and compare to different\ntheoretical predictions. We obtain unambiguous evidence that the coefficients\nof $T^2$ and $T^4$ terms coincide with those of the Nambu-Goto string, as\nexpected, while the $T^6$ term strongly differs and is characteristic of the\nuniversality class of this specific gauge theory.",
        "positive": "Multi-hadron interactions from lattice QCD: First-principles calculations of multi-hadron dynamics are a crucial goal in\nlattice QCD. Significant progress has been achieved in developing,\nimplementing, and applying theoretical tools that connect finite-volume\nquantities to their infinite-volume counterparts. Here, I review some recent\ntheoretical developments and numerical results regarding multi-particle\nquantities in a finite volume. These results include $N\\pi$ scattering, systems\nof two and three mesons at maximal isospin, three-body resonances in a toy\nmodel, and the formulation of effective theories in finite volume for\nmulti-nucleon systems."
    },
    {
        "anchor": "Lattice QCD analysis for Faddeev-Popov eigenmodes in terms of gluonic\n  momentum components in the Coulomb gauge: We analyze the relation between Faddeev-Popov eigenmodes and gluon-momentum\ncomponents in the Coulomb gauge using SU(3) lattice QCD. In the Coulomb gauge,\nthe color-Coulomb energy is largely enhanced by near-zero Faddeev-Popov\neigenmodes, which would lead to the confining potential. By the\nultraviolet-momentum gluon cut, the color-Coulomb energy and the Faddeev-Popov\nspectrum are almost unchanged. In contrast to the ultraviolet insensitivity,\nthe color-Coulomb energy and the Faddeev-Popov eigenmodes drastically change by\ninfrared-momentum gluon cut. Without infrared gluons, the color-Coulomb energy\ntends to become non-confining, and near-zero Faddeev-Popov eigenmodes vanish.\nWe also investigate the full FP eigenmodes, and find that infrared gluons\nwidely influence both high and low Faddeev-Popov eigenmodes.",
        "positive": "Baryon interactions from lattice QCD with physical masses ---\n  strangeness $S=-1$ sector ---: We present our recent results of baryon interactions with strangeness $S=-1$\nbased on Nambu-Bethe-Salpeter (NBS) correlation functions calculated from\nlattice QCD with almost physical quark masses corresponding to\n$(m_\\pi,m_K)\\approx(146,525)$ MeV and large volume $(La)^4=(96a)^4\\approx$ (8.1\nfm)$^4$. In order to perform a comprehensive study of baryon interactions, a\nlarge number of NBS correlation functions from NN to $\\Xi\\Xi$ are calculated\nsimultaneously by using large scale computer resources. In this contribution,\nwe focus on the strangeness $S=-1$ channels of the hyperon interactions by\nmeans of HAL QCD method. Four sets of three potentials (the $^3S_1-^3D_1$\ncentral, $^3S_1-^3D_1$ tensor, and the $^1S_0$ central potentials) are\npresented for the $\\Sigma N - \\Sigma N$ (the isospin $I=3/2$) diagonal, the\n$\\Lambda N - \\Lambda N$ diagonal, the $\\Lambda N \\rightarrow \\Sigma N$\ntransition, and the $\\Sigma N - \\Sigma N$ ($I=1/2$) diagonal interactions.\nScattering phase shifts for $\\Sigma N$ $(I=3/2)$ system are presented."
    },
    {
        "anchor": "Finite volume corrections to pi-pi scattering: Lattice QCD studies of hadron-hadron interactions are performed by computing\nthe energy levels of the system in a finite box. The shifts in energy levels\nproportional to inverse powers of the volume are related to scattering\nparameters in a model independent way. In addition, there are non-universal\nexponentially suppressed corrections that distort this relation. These terms\nare proportional to exp(-m_pi L) and become relevant as the chiral limit is\napproached. In this paper we report on a one-loop chiral perturbation theory\ncalculation of the leading exponential corrections in the case of I=2 pi-pi\nscattering near threshold.",
        "positive": "Dimensional Reduction and Non-perturbative generation of magnetic mass\n  in non-abelian gauge theory at finite temperature: A non-perturbative mass of $0.2719 g^2 T$ is generated for the magnetic\nsector of the $SU(2)$ gauge theory at high temperature due to the condensation\nof Polyakov \\cite{Pol} monopole and antimonopole which form a magnetic glue\nball. String tension for the spatial wilson loop is calculated which is of the\nsame order of magnitude and has same temperature dependence as obtained from\nlattice simulation."
    },
    {
        "anchor": "Stochastic Estimator Techniques and Their Implementation on Distributed\n  Parallel Computers: The calculation of physical quantities by lattice QCD simulations requires in\nsome important cases the determination of the inverse of a very large matrix.\nIn this article we describe how stochastic estimator methods can be applied to\nthis problem, and how such techniques can be efficiently implemented on\nparallel computers.",
        "positive": "The triviality bound on the Higgs mass; its value and what it means: Older lattice work exploring the Higgs mass triviality bound is briefly\nreviewed. It indicates that a strongly interacting scalar sector in the minimal\nstandard model cannot exist; on the other hand low energy QCD phenomenology\nmight be interpreted as an indication that it could. We attack this puzzle\nusing the $1/N$ expansion and discover a simple criterion for selecting a\nlattice action that is more likely to produce a heavy Higgs particle. Depending\non the precise form of the limitation put on the cutoff effects, our large $N$\ncalculations, when combined with old numerical data, suggest that the Higgs\nmass bound might be around 750 $GeV$, which is higher than the $\\sim 650~GeV$\npreviously obtained. Preliminary numerical work indicates that an increase of\nat least 19\\% takes place at $N=4$ on the $F_4$ lattice when the old simple\naction is replaced with a new action (still containing only nearest neighbor\ninteractions) if one uses the lattice spacing as the physical cutoff for both\nactions. It appears that, while a QCD like theory could produce $M_H / F ~ \\sim\n6$, a meaningful ``minimal elementary Higgs'' theory cannot have $M_H/ F~\n\\gtapprox 3$. Still, even at 750 $GeV$, the Higgs particle is so wide ($\\sim\n290~$GeV), that one cannot argue any more that the scalar sector is weakly\ncoupled."
    },
    {
        "anchor": "Isovector Axial Vector Form Factors of the Nucleon from Lattice QCD with\n  $N_{f}=2+1$ $\\mathcal O(a)$-improved Wilson Fermions: We present the analysis of isovector axial vector nucleon form factors on a\nset of $N_f=2+1$ CLS ensembles with $\\mathcal O(a)$-improved Wilson fermions\nand L\\\"uscher-Weisz gauge action. The set of ensembles covers a pion mass range\nof $130-353\\,$MeV with lattice spacings between $0.05\\,$fm and $0.09\\,$fm. In\nparticular, the set includes a $L/a=96$ ensemble at the physical pion mass. For\nthe purpose of the form factor extraction, we employ both the summed operator\ninsertion method (summation method) and explicit two-state fits in order to\naccount for excited-state contributions to the nucleon correlation functions.\nTo describe the $Q^{2}$-behavior of the form factors, we perform $z$-expansion\nfits. Finally, we present HBChPT-inspired chiral and continuum extrapolations\nof the axial charge and radius.",
        "positive": "QCD, Supersymmetric QCD, Lattice QCD and String Theory: Synthesis on the\n  Horizon?: Supersymmetric gauge theories in four dimensions have taught us many\nimportant physics lessons. These can both inform and be informed by future work\non the lattice. I focus on three issues: the properties of supersymmetric\nYang-Mills theory and its relation to the non-supersymmetric case; the\nproperties of gauge theories with matter and their relation to real QCD; and,\nbriefly, the recent discovery that gauge theories and string theories are more\ndeeply connected than ever previously realized. Specific questions for lattice\ngauge theorists to consider are raised in the context of the first two topics."
    },
    {
        "anchor": "Scaling in SU(3) theory with a MCRG improved lattice action: We test various improved gauge actions which are made of linear combinations\nof Wilson loops. We observe the restoration of rotational symmetry in the\nstatic interquark potential already on coarse lattices as small as 6^3x12.\nFurthermore, we study scaling and asymptotic scaling of the string tension with\na MCRG-improved action on 12^3x24 lattices. Preliminary results show that\nscaling sets in at a ~ 0.3 fm.",
        "positive": "Equation of State in 2+1 Flavor QCD at High Temperatures: We calculate the Equation of State at high temperatures in 2+1 flavor QCD\nusing the highly improved staggered quark action. We study the lattice spacing\ndependence of the pressure at high temperatures using lattices with temporal\nextent $N_{\\tau}=6,~8,~10$ and $12$ and perform continuum extrapolations. We\nalso give a continuum estimate for the Equation of State up to temperatures\n$T=2$ GeV, which are then compared with results of the weak-coupling\ncalculations. We find a reasonably good agreement with the weak-coupling\ncalculations at the highest temperatures."
    },
    {
        "anchor": "Quark Masses on the Lattice: Light and Heavy: I review the current status of lattice calculations of light and heavy quark\nmasses. Significant progresses, in these studies, have been allowed by the\nintroduction of improved actions and non-perturbative renormalization\ntechniques. Current determinations of light quark masses are accurate at the\nlevel of 20%, where the main source of uncertainty is represented by the\nquenching error. The determination of the bottom quark mass is accurate at the\nimpressive level of 2%. As final averages of lattice results, I quote mud(2\nGeV) = (4.5 +- 1.0) MeV, ms(2 GeV) = (110 +- 25) MeV and mb(mb) = (4.26 +-\n0.09) GeV.",
        "positive": "1st or 2nd; the order of finite temperature phase transition of Nf=2 QCD\n  from effective theory analysis: In the previous work, we have shown that the SU(2) chiral symmetry recovered\nabove the critical temperature gives a strong constraint on the Dirac\neigenvalue spectrum and this constraint is strong enough for a set of anomalous\nU(1) chiral symmetry breaking operators to vanish in the thermodynamical and\nchiral limits. We use this condition as an input and impose a constraint on the\nLandau low energy effective theory of QCD. The only constraint we can set is\nthat the mass splitting term between the pion and eta meson should vanish. All\nthe singlet/non-singlet scalar/pseudo-scalar mesons contribute to the effective\ntheory. We evaluate the renormalization group $\\beta$-function for the\neffective theory using the $\\epsilon$-expansion at one loop level, but find no\nstable infra-red fixed point except for the trivial Gaussian one. The chiral\nphase transition seems to be of first order."
    },
    {
        "anchor": "Calculating B-meson decay constants using domain-wall light quarks and\n  nonperturbatively tuned relativistic b-quarks: We calculate B-physics quantities using the RBC/UKQCD 2+1 flavor domain-wall\nplus Iwasaki lattices and the relativistic heavy quark action developed by\nChrist, Li and Lin. After tuning these parameters nonperturbatively, we present\nour preliminary results for the calculation of the decay constants f_B and\nf_{B_s} analyzing data at two lattice spacings of a ~ 0.11 fm and a ~ 0.08 fm.",
        "positive": "Glueball spectroscopy in lattice QCD using gradient flow: Removing ultraviolet noise from the gauge fields is necessary for glueball\nspectroscopy in lattice QCD. It is known that the Yang-Mills gradient flow\nmethod is an alternative approach instead of link smearing or link fuzzing in\nvarious aspects. In this work we study the application of the gradient flow\ntechnique to the construction of the extended glueball operators. We examine a\nsimple application of the gradient flow method, which has some problems in\nglueball mass calculations at large flow time because of its nature of\ndiffusion in space-time. To avoid this problem, the spatial links are evolved\nby the ``spatial gradient flow'', that is defined to restrict the diffusion to\nspatial directions only. We test the spatial gradient flow in calculations of\nglueball two-point functions and Wilson loops as a new smearing method, and\nthen discuss its efficiency in comparison with the original gradient flow\nmethod and the conventional method. Furthermore, to demonstrate the feasibility\nof our proposed method, we determine the masses of the three lowest-lying\nglueball states, corresponding to the $0^{++}$, $2^{++}$ and $0^{-+}$\nglueballs, in the continuum limit in the pure Yang-Mills theory."
    },
    {
        "anchor": "The de Sitter Instanton from Euclidean Dynamical Triangulations: We study the emergence of de Sitter space in Euclidean dynamical\ntriangulations (EDT). Working within the semi-classical approximation, it is\npossible to relate the lattice parameters entering the simulations to the\npartition function of Euclidean quantum gravity. We verify that the EDT\ngeometries behave semi-classically, and by making contact with the Hawking-Moss\ninstanton solution for the Euclidean partition function, we show how to extract\na value of the renormalized Newton's constant from the simulations. This value\nis consistent with that of our previous determination coming from the\ninteraction of scalar particles. That the same universal constant appears in\nthese two different sectors of the theory is a strong indication that EDT\nprovides a viable formulation of quantum gravity.",
        "positive": "Finite-volume effects and meson scattering in the 2-flavour Schwinger\n  model: We investigate the 2-flavour Schwinger model in the canonical formulation\nwith fixed fermion numbers. We use Wilson fermions and a formalism which\ndescribes the determinant of the Dirac operator in terms of dimensionally\nreduced canonical transfer matrices. These transfer matrices allow the direct\nexamination of arbitrary multi-particle (meson) sectors and the determination\nof the corresponding ground-state energies. We discuss the finite-volume\neffects in the meson mass. From the 2-meson energies, we determine the\nscattering phase shifts and compare the 3-meson energies at finite volume to\npredictions based on 3-particle quantization conditions."
    },
    {
        "anchor": "Spectral functions at small energies and the electrical conductivity in\n  hot, quenched lattice QCD: In lattice QCD, the Maximum Entropy Method can be used to reconstruct\nspectral functions from euclidean correlators obtained in numerical\nsimulations. We show that at finite temperature the most commonly used\nalgorithm, employing Bryan's method, is inherently unstable at small energies\nand give a modification that avoids this. We demonstrate this approach using\nthe vector current-current correlator obtained in quenched QCD at finite\ntemperature. Our first results indicate a small electrical conductivity above\nthe deconfinement transition.",
        "positive": "O(a^2) cutoff effects in Wilson fermion simulations: We show that the size of the O(a^2) flavour violating cutoff artifacts that\nhave been found to affect the value of the neutral pion mass in simulations\nwith maximally twisted Wilson fermions is controlled by a continuum QCD\nquantity that is fairly large and is determined by the dynamical mechanism of\nspontaneous chiral symmetry breaking. One can argue that the neutral pion mass\nis the only physical quantity blurred by such cutoff effects. O(a^2)\ncorrections of this kind are also present in standard Wilson fermion\nsimulations, but they can either affect the determination of the pion mass or\nbe shifted from the latter to other observables, depending on the way the\ncritical mass is evaluated."
    },
    {
        "anchor": "Double Hairpin Diagrams and the Planar Equivalence of N=1 Supersymmetric\n  Yang-Mills Theory and One-Flavor QCD: Recent work by Armoni, Shifman, and Veneziano suggests a large-N equivalence\nbetween supersymmetric Yang-Mills Theory and one-flavor QCD. One consequence of\nthis \"orientifold projection\" is that scalar and pseudoscalar mesons in\none-flavor QCD should have degenerate mass since they lie within the same\nWess-Zumino supermultiplet. We use lattice calculations to investigate the mass\nshifts caused by \"double-hairpin\" annihilation diagrams in quenched QCD to test\nfor this degeneracy. Similar quark-antiquark annihilation processes are studied\nin the 2-dimensional CP(N-1) model with quenched fermions.",
        "positive": "Improved automated lattice perturbation theory in background field gauge: We present an algorithm to automatically derive Feynman rules for lattice\nperturbation theory in background field gauge. Vertices with an arbitrary\nnumber of both background and quantum legs can be derived automatically from\nboth gluonic and fermionic actions. The algorithm is a generalisation of our\nearlier algorithm based on prior work by L\\\"uscher and Weisz. We also present\ntechniques allowing for the parallelisation of the evaluation of the often\nrather complex lattice Feynman rules that should allow for efficient\nimplementation on GPUs, but also give a significant speed-up when calculating\nthe derivatives of Feynman diagrams with respect to external momenta."
    },
    {
        "anchor": "Excitations of isolated static charges in q=2 Abelian Higgs theory: In this report, I discuss lattice Monte Carlo evidence of excitations of\nisolated static charges in q=2 Abelian Higgs theory. The localized excitations\nare excited states of the interacting fields surrounding the static charges.",
        "positive": "How good is the quenched approximation of QCD?: The quenched approximation for QCD is, at present and in the foreseeable\nfuture, unavoidable in lattice calculations with realistic choices of the\nlattice spacing, volume and quark masses. In this talk, I review an analytic\nstudy of the effects of quenching based on chiral perturbation theory. Quenched\nchiral perturbation theory leads to quantitative insight on the difference\nbetween quenched and unquenched QCD, and reveals clearly some of the diseases\nwhich are expected to plague quenched QCD. Uses jnl.tex and epsf.tex for figure\n3. Figures 1 and 2 not included, sorry. Available as hardcopy on request."
    },
    {
        "anchor": "Instanton-dyon ensembles reproduce deconfinement and chiral restoration\n  phase transitions: Paradigm shift in gauge topology at finite temperatures, from the instantons\nto their constituents -- instanton-dyons -- has recently lead to studies of\ntheir ensembles and very significant advances. Like instantons, they have\nfermionic zero modes, and their collectivization at sufficiently high density\nexplains the {\\em chiral symmetry breaking transition}. Unlike instantons,\nthese objects have electric and magnetic charges. Simulations of the\ninstanton-dyon ensembles have demonstrated that their back reaction on the\nPolyakov line modifies its potential and generates the {\\em deconfinement phase\ntransition}. For the $N_c=2$ gauge theory the transition is second order, for\nQCD-like theory with\n  $N_c=2$ and two light quark flavors $N_f=2$ both transitions are weak\ncrossovers at happening at about the same condition. Introduction of\nquark-flavor-dependent periodicity phases (imaginary chemical potentials) leads\nto drastic changes in both transitions. In particulaly, in the so called\n$Z(N_c)-QCD$ model the deconfinement transforms to strong first order\ntransition, while the chiral condensate does not disappear at all. The talk\nwill also cover more detailed studies of correlations between the dyons,\neffective eta' mass and other screening masses.",
        "positive": "Loop Action for Lattice U(1) Gauge Theory: It is showed that the very recently introduced Lagrangian $loop$ formulation\nof the lattice Maxwell theory is equivalent to the Villain form in 2+1\ndimensions. A transparent description of the classical $loop$ action is given\nin pure geometrical terms for the $2+1$ and $3+1$ dimensional cases."
    },
    {
        "anchor": "Multi-Grid Monte Carlo via $XY$ Embedding. II. Two-Dimensional $SU(3)$\n  Principal Chiral Model: We carry out a high-precision simulation of the two-dimensional $SU(3)$\nprincipal chiral model at correlation lengths $\\xi$ up to $\\sim 4 \\times 10^5$,\nusing a multi-grid Monte Carlo (MGMC) algorithm and approximately one year of\nCray C-90 CPU time. We extrapolate the finite-volume Monte Carlo data to\ninfinite volume using finite-size-scaling theory, and we discuss carefully the\nsystematic and statistical errors in this extrapolation. We then compare the\nextrapolated data to the renormalization-group predictions. The deviation from\nasymptotic scaling, which is $\\approx 12%$ at $\\xi \\sim 25$, decreases to\n$\\approx 2%$ at $\\xi \\sim 4 \\times 10^5$. We also analyze the dynamic critical\nbehavior of the MGMC algorithm using lattices up to $256 \\times 256$, finding\nthe dynamic critical exponent $z_{int,{\\cal M}^2} \\approx 0.45 \\pm 0.02$\n(subjective 68% confidence interval). Thus, for this asymptotically free model,\ncritical slowing-down is greatly reduced compared to local algorithms, but not\ncompletely eliminated.",
        "positive": "Gauge-invariant screening masses and static quark free energies in $N_f\n  = 2+1$ QCD at non-zero baryon density: We discuss the extension of gauge-invariant electric and magnetic screening\nmasses in the Quark-Gluon Plasma to the case of a finite baryon density,\ndefining them in terms of a matrix of Polyakov loop correlators. We present\nlattice results for $N_f=2+1$ QCD with physical quark masses, obtained using\nthe imaginary chemical potential approach, which indicate that the screening\nmasses increase as a function of $\\mu_B$. A separate analysis is carried out\nfor the theoretically interesting case $\\mu_B/T=3 i \\pi$, where charge\nconjugation is not explicitly broken and the usual definition of the screening\nmasses can be used for temperatures below the Roberge-Weiss transition.\nFinally, we investigate the dependence of the static quark free energy on the\nbaryon chemical potential, showing that it is a decreasing function of $\\mu_B$\nwhich displays a peculiar behavior as the pseudocritical transition temperature\nat $\\mu_B=0$ is approached."
    },
    {
        "anchor": "Generalized Hybrid Monte-Carlo: We propose a modification of the Hybrid Monte-Carlo method to sample\nequilibrium distributions of continuous field models. The method allows an\nefficient implementation of Fourier acceleration and is shown to reduce\ncompletely critical slowing down for the Gaussian model, i. e., $z=0$.",
        "positive": "Initial nucleon structure results with chiral quarks at the physical\n  point: We report initial nucleon structure results computed on lattices with 2+1\ndynamical M\\\"obius domain wall fermions at the physical point generated by the\nRBC and UKQCD collaborations. At this stage, we evaluate only connected quark\ncontributions. In particular, we discuss the nucleon vector and axial-vector\nform factors, nucleon axial charge and the isovector quark momentum fraction.\nFrom currently available statistics, we estimate the stochastic accuracy of the\ndetermination of $g_A$ and $<x>_{u-d}$ to be around 10%, and we expect to\nreduce that to 5% within the next year. To reduce the computational cost of our\ncalculations, we extensively use acceleration techniques such as low-eigenmode\ndeflation and all-mode-averaging (AMA). We present a method for choosing\noptimal AMA parameters."
    },
    {
        "anchor": "Large N reduction with overlap fermions: We revisit quenched reduction with fermions and explain how some old problems\ncan be avoided using the overlap Dirac operator.",
        "positive": "Monopole Spectra in non-Abelian Gauge Theories: We study the continuum limit of the length spectrum of magnetic monopole\nstructures found after various Abelian projections of pure gauge SU(2),\nincluding the maximally Abelian gauge. We comment on Gribov copies, and\nmeasurements of the string tension."
    },
    {
        "anchor": "Critical Exponents of the Three Dimensional Random Field Ising Model: The phase transition of the three--dimensional random field Ising model with\na discrete ($\\pm h$) field distribution is investigated by extensive Monte\nCarlo simulations. Values of the critical exponents for the correlation length,\nspecific heat, susceptibility, disconnected susceptibility and magnetization\nare determined simultaneously via finite size scaling. While the exponents for\nthe magnetization and disconnected susceptibility are consistent with a first\norder transition, the specific heat appears to saturate indicating no latent\nheat. Sample to sample fluctuations of the susceptibilty are consistent with\nthe droplet picture for the transition.",
        "positive": "CP Violation and the CKM Matrix: This lecture provides a general overview of CP violation, emphasizing CP\nviolation in flavour-violating interactions, such as due to the\nKobayashi-Maskawa mechanism."
    },
    {
        "anchor": "Anatomy of String Breaking in QCD: We investigate the string breaking mechanism in n_f=2 QCD. We discuss the\nlattice techniques used and present results on energy levels and mixing angle\nof the static BBbar|QbarQ two-state system. The string breaking is visualized,\nby means of an animation of the action density distribution as a function of\nthe static colour source-antisource separation.",
        "positive": "Static quark-antiquark pair free energy and screening masses: continuum\n  results at the QCD physical point: We study the correlators of Polyakov loops, and the corresponding gauge\ninvariant free energy of a static quark-antiquark pair in 2+1 flavor QCD at\nfinite temperature. Our simulations were carried out on $N_t$ = 6, 8, 10, 12,\n16 lattices using a Symanzik improved gauge action and a stout improved\nstaggered action with physical quark masses. The free energies calculated from\nthe Polyakov loop correlators are extrapolated to the continuum limit. For the\nfree energies we use a two step renormalization procedure that only uses data\nat finite temperature. We also measure correlators with definite Euclidean time\nreversal and charge conjugation symmetry to extract two different screening\nmasses, one in the magnetic, and one in the electric sector, to distinguish two\ndifferent correlation lengths in the full Polyakov loop correlator. This\nconference contribution is based on the paper: JHEP 1504 (2015) 138"
    },
    {
        "anchor": "Lattice QCD package GWU-code and QUDA with HIP: The open source HIP platform for GPU computing provides an uniform framework\nto support both the NVIDIA and AMD GPUs, and also the possibility to porting\nthe CUDA code to the HIP- compatible one. We present the porting progress on\nthe Overlap fermion inverter (GWU-code) and also the general Lattice QCD\ninverter package - QUDA. The manual of using QUDA on HIP and also the tips of\nporting general CUDA code into the HIP framework are also provided.",
        "positive": "Precision study of the continuum SU(3) Yang-Mills theory: how to use\n  parallel tempering to improve on supercritical slowing down for first order\n  phase transitions: We perform large scale simulations to characterize the transition in quenched\nQCD. It is shown by a rigorous finite size scaling that the transition is of\nfirst order. After this qualitative feature quantitative results are obtained\nwith unprecedented precision: we calculate the transition temperature\n$w_0T_c$=0.25384(23), -- which is the first per-mill accurate result in QCD\nthermodynamics -- and the latent heat $\\Delta E/T_c^4$=1.025(21)(27) in both\ncases carrying out controlled continuum and infinite volume extrapolations. As\nit is well known the cost of lattice simulations explodes in the vicinity of\nphase transitions, a phenomenon called critical slowing down for second order\nphase transitions and supercritical slowing down for first order phase\ntransitions. We show that a generalization of the parallel tempering algorithm\nof Marinari and Parisi [Europhys. Lett. 19, 451 (1992)] originally for spin\nsystems can efficiently overcome these difficulties even if the transition is\nof first order, like in the case of QCD without quarks, or with very heavy\nquarks. We also report on our investigations on the autocorrelation times and\nother details."
    },
    {
        "anchor": "Remarks on the Maximum Entropy Method applied to finite temperature\n  lattice QCD: We make remarks on the Maximum Entropy Method (MEM) for studies of the\nspectral function of hadronic correlators in finite temperature lattice QCD. We\ndiscuss the virtues and subtlety of MEM in the cases that one does not have\nenough number of data points such as at finite temperature. Taking these points\ninto account, we suggest several tests which one should examine to keep the\nreliability for the results, and also apply them using mock and lattice QCD\ndata.",
        "positive": "Dressed Polyakov loops and center symmetry from Dirac spectra: We construct a novel observable for finite temperature QCD that relates\nconfinement and chiral symmetry. It uses phases as boundary conditions for the\nfermions. We discuss numerical and analytical aspects of this observable, like\nits spectral behavior below and above the critical temperature, as well as the\nconnection to chiral condensate and center symmetry."
    },
    {
        "anchor": "Quantum geometry of topological gravity: We study a c=-2 conformal field theory coupled to two-dimensional quantum\ngravity by means of dynamical triangulations. We define the geodesic distance r\non the triangulated surface with N triangles, and show that dim[r^{d_H}]=\ndim[N], where the fractal dimension d_H = 3.58 +/- 0.04. This result lends\nsupport to the conjecture d_H = -2\\alpha_1/\\alpha_{-1}, where \\alpha_{-n} is\nthe gravitational dressing exponent of a spin-less primary field of conformal\nweight (n+1,n+1), and it disfavors the alternative prediction d_H =\n-2/\\gamma_{str}. On the other hand, we find dim[l] = dim[r^2] with good\naccuracy, where l is the length of one of the boundaries of a circle with\n(geodesic) radius r, i.e. the length l has an anomalous dimension relative to\nthe area of the surface. It is further shown that the spectral dimension d_s =\n1.980 +/- 0.014 for the ensemble of (triangulated) manifolds used. The results\nare derived using finite size scaling and a very efficient recursive sampling\ntechnique known previously to work well for c=-2.",
        "positive": "New universality class of chiral symmetry breaking in the strongly\n  coupled U(1) $\u03c7U \u03c6$ model: We describe a 4D U(1) lattice gauge theory with charged scalar $\\phi$ and\nfermion $\\chi$ matter fields ($\\chi U \\phi$ model). At sufficiently strong\ngauge coupling, the chiral symmetry is broken and the mass of the unconfined\ncomposite fermion $F = \\bar{\\chi} \\phi $ is generated dynamically by gauge\ninteraction. The scalar supresses this symmetry breaking and induces a line of\nsecond order transitions with scaling properties similar to the\nNambu--Jona-Lasinio model. However, in the vicinity of a particular,\ntricritical point the scaling properties are different. Here we study the\neffective Yukawa coupling between the massive fermion and the Goldstone boson.\nThe perturbative triviality bound of Yukawa models is nearly saturated. The\ntheory is similar to strongly coupled Yukawa models except the occurrence of an\nadditional state -- a gauge ball of mass $m_S \\simeq 1/2 m_F$. This, and\nnon-classical values of tricritical exponents suggest that at the tricritical\npoint the $\\chi U \\phi$ model constitutes a new universality class.\nNevertheless, it might be a microscopic model for the Higgs-Yukawa mechanism of\nsymmetry breaking."
    },
    {
        "anchor": "Adjoint torelons, and the persistence of color electric flux tubes in\n  the deconfined phase: It is argued that the adjoint torelon loop, i.e. a Polyakov loop in the\nadjoint representation running in a spatial, rather than temporal, direction,\nis an observable which is sensitive to the presence of long color electric flux\ntubes at high temperatures. We show via lattice Monte Carlo simulations that\nthis observable has a sharp peak at the deconfinement transition, remains much\nlarger than the vacuum value for some range of $T>T_c$, and falls below the\nvacuum value for $T > 2T_c$. This result suggests that long electric flux tubes\nmay persist for a finite range of temperatures past the deconfinement\ntransition, and at some stage disappear, presumably melting into a plasma of\ngluons. As a side remark, we point out that our results at $T<T_c$ imply that\nthe eigenvalues of ordinary Polyakov loop holonomies in the confinement phase\nhave a slight tendency to attract rather than repel, which may be relevant to\ncertain models of confinement.",
        "positive": "Confining and chiral properties of QCD in extremely strong magnetic\n  fields: We investigate, by numerical lattice simulations, the static quark-antiquark\npotential, the flux tube properties and the chiral condensate for $N_f = 2+1$\nQCD with physical quark masses in the presence of strong magnetic fields, going\nup to $eB = 9$ GeV$^2$, with continuum extrapolated results. The string tension\nfor quark-antiquark separations longitudinal to the magnetic field is\nsuppressed by one order of magnitude at the largest explored magnetic field\nwith respect to its value at zero magnetic background, but is still\nnon-vanishing; in the transverse direction, instead, the string tension is\nenhanced but seems to reach a saturation at around 50 % of its value at $B =\n0$. The flux tube shows a consistent suppression/enhancement of the overall\namplitude, with mild modifications of its profile. Finally, we observe magnetic\ncatalysis in the whole range of explored fields with a behavior compatible with\na lowest Landau level approximation, in particular with a linear dependence of\nthe chiral condensate on $B$ which is in agreement, within errors, with that\nalready observed for $eB \\sim 1$ GeV$^2$."
    },
    {
        "anchor": "Looking behind the Standard Model with lattice gauge theory: Models for what may lie behind the Standard Model often require\nnon-perturbative calculations in strongly coupled field theory. This creates\nopportunities for lattice methods, to obtain quantities of phenomenological\ninterest as well as to address fundamental dynamical questions. I survey recent\nwork in this area.",
        "positive": "Machine learning approaches to the QCD transition: We study the high temperature transition in pure $SU(3)$ gauge theory and in\nfull QCD with 3D-convolutional neural networks trained as parts of either\nunsupervised or semi-supervised learning problems. Pure gauge configurations\nare obtained with the MILC public code and full QCD are from simulations of\n$N_f=2+1+1$ Wilson fermions at maximal twist. We discuss the capability of\ndifferent approaches to identify different phases using as input the\nconfigurations of Polyakov loops. To better expose fluctuations, a standardized\nversion of Polyakov loops is also considered."
    },
    {
        "anchor": "Gluon Digitization via Character Expansion for Quantum Computers: Efficient digitization is required for quantum simulations of gauge theories.\nSchemes based on discrete subgroups use a smaller, fixed number of qubits at\nthe cost of systematic errors. We systematize this approach by deriving the\nsingle plaquette action through matching the continuous group action to that of\na discrete one via group character expansions modulo the field fluctuation\ncontributions. We accompany this scheme by simulations of pure gauge over the\nlargest discrete crystal-like subgroup of $SU(3)$ up to the fifth-order in the\ncoupling constant.",
        "positive": "Localization of Low Lying Eigenmodes for Chirally Symmetric Dirac\n  Operator: We consider properties of zero and near-zero modes for overlap fermion\noperator in SU(2) lattice gluodynamics. The density of the states is of the\norder of Lambda(QCD) while the localization volume of the modes tends to zero\nin physical units with the lattice spacing tending to zero. The situation\nchanges drastically when we study \"vortex removed\" configurations."
    },
    {
        "anchor": "Charmonium potential from full lattice QCD: We present both spin-independent and -dependent parts of a central interquark\npotential for charmonium states, which is calculated in 2+1 flavor dynamical\nlattice QCD using the PACS-CS gauge configurations with a lattice cutoff of\na^{-1}~2.2 GeV. Our simulations are performed with a relativistic heavy quark\naction for the charm quark at the lightest pion mass, M_\\pi=156(7) MeV, in a\nspatial volume of 3fm^3. We observe that the spin-independent charmonium\npotential obtained from lattice QCD with almost physical quark masses is quite\nsimilar to the Conrnell potential used in non-relativistic potential models.\nThe spin-spin potential properly exhibits the short range repulsive\ninteraction, while its r-dependence is different from either a point-like\nspin-spin potential generated by one-gluon exchange or a phenomenological\nfinite-range one adopted in quark potential models.",
        "positive": "Gravitational binding in 4D dynamical triangulation: In the dynamical triangulation model of four dimensional euclidean quantum\ngravity we investigate gravitational binding. Two scalar test particles\n(quenched approximation) have a positive binding energy, thereby showing that\nthe model can represent gravitational attraction."
    },
    {
        "anchor": "Finite Temperature Landau Gauge Lattice Quark Propagator: The quark propagator at finite temperature is investigated using quenched\ngauge configurations. The propagator form factors are investigated for\ntemperatures above and below the gluon deconfinement temperature $T_c$ and for\nthe various Matsubara frequencies. Significant differences between the\nfunctional behaviour below and above $T_c$ are observed both for the quark wave\nfunction and the running quark mass. The results for the running quark mass\nindicate a strong link between gluon dynamics, the mechanism for chiral\nsymmetry breaking and the deconfinement mechanism. For temperatures above $T_c$\nand for low momenta, our results support also a description of quarks as free\nquasi-particles.",
        "positive": "Chiral Invariance and Species Doublers in Generic Fermion Models on the\n  Lattice: Discussions are made on the structures of chirally invariant lattice actions\nwithout any restriction of hermiticity. With the help of the Ward-Takahashi\nidentity a general conclusion can be derived that there must be species\ndoublers in any chirally invariant model provided that the model is chosen as\nwell-regularized, that is, there is no singularity in the propagator after\nintroducing fermion mass on the lattice. Various examples are discussed to pick\nup better models defined in the sense that the number of species doubler is\nsmaller than that of the naive Dirac action."
    },
    {
        "anchor": "Unified chiral analysis of the vector meson spectrum from lattice QCD: The chiral extrapolation of the vector meson mass calculated in\npartially-quenched lattice simulations is investigated. The leading one-loop\ncorrections to the vector meson mass are derived for partially-quenched QCD. A\nlarge sample of lattice results from the CP-PACS Collaboration is analysed,\nwith explicit corrections for finite lattice spacing artifacts. To incorporate\nthe effect of the opening decay channel as the chiral limit is approached, the\nextrapolation is studied using a necessary phenomenological extension of chiral\neffective field theory. This chiral analysis also provides a quantitative\nestimate of the leading finite volume corrections. It is found that the\ndiscretisation, finite-volume and partial quenching effects can all be very\nwell described in this framework, producing an extrapolated value of M_\\rho in\nexcellent agreement with experiment. This procedure is also compared with\nextrapolations based on polynomial forms, where the results are much less\nenlightening.",
        "positive": "Structure of Abrikosov Vortices in SU(2) Lattice Gauge Theory: We calculate the electric flux and magnetic monopole current distribution in\nthe presence of a static quark-antiquark pair for SU(2) lattice gauge theory in\nthe maximal Abelian gauge. The current distribution confines the flux in a dual\nAbrikosov vortex whose core size is comparable to the flux penetration depth.\nThe observed structure is described by a dual Ginzburg-Landau model."
    },
    {
        "anchor": "Critical dynamics of relativistic diffusion: We study the dynamics of self-interacting scalar fields with $Z_2$ symmetry\ngoverned by a relativistic Israel-Stuart type diffusion equation in the\nvicinity of a critical point. We calculate spectral functions of the order\nparameter in mean-field approximation as well as using first-principles\nclassical-statistical lattice simulations in real-time. We observe that the\nspectral functions are well-described by single Breit-Wigner shapes. Away from\ncriticality, the dispersion matches the expectations from the mean-field\napproach. At the critical point, the spectral functions largely keep their\nBreit-Wigner shape, albeit with non-trivial power-law dispersion relations. We\nextract the characteristic time-scales as well as the dynamic critical exponent\n$z$, verifying the existence of a dynamic scaling regime. In addition, we\nderive the universal scaling functions implied by the Breit-Wigner shape with\ncritical power-law dispersion and show that they match the data. Considering\nequations of motion for a system coupled to a heat bath as well as an isolated\nsystem, we perform this study for two different dynamic universality classes,\nboth in two and three spatial dimensions.",
        "positive": "Lattice super-Yang-Mills using domain wall fermions in the chiral limit: Lattice N=1 super-Yang-Mills theory formulated using Ginsparg-Wilson fermions\nprovides a rigorous non-perturbative definition of the continuum theory that\nrequires no fine-tuning as the lattice spacing is reduced to zero. Domain wall\nfermions are one explicit scheme for achieving this and using them we have\nperformed large-scale Monte Carlo simulations of the theory for gauge group\nSU(2). We have measured the gaugino condensate, static potential, Creutz ratios\nand residual mass for several values of the domain wall separation L_s,\nfour-dimensional lattice volume, and two values of the gauge coupling. With\nthis data we are able to extrapolate the gaugino condensate to the chiral\nlimit, to express it in physical units, and to establish important benchmarks\nfor future studies of super-Yang-Mills on the lattice."
    },
    {
        "anchor": "Charmonium Potentials at Finite Temperature: The charmonium states at non-zero temperature are studied on anisotropic\nlattices with 2 dynamical quark flavours. Non-local operators are used to\ndetermine the Nambu-Bethe-Salpeter (NBS) wavefunctions via both conventional\nfitting methods and the Maximum Entropy Method. The interquark potential is\ndetermined from the solution of the Schrodinger equation, given the NBS\nwavefunction as input following the HAL QCD method. We observe a temperature\ndependent potential which becomes steeper as the temperature decreases.",
        "positive": "Multiple breaking patterns in the Brout-Englert-Higgs effect beyond\n  perturbation theory: In many BSM theories, especially GUTs, introducing a Brout-Englert-Higgs\neffect allows for multiple breaking patterns of the gauge symmetry. The\npossibility to select a particular pattern is usually decisive for the\nphenomenological viability of a theory. Beyond perturbation theory it is\nnecessary to replace the Brout-Englert-Higgs effect by a manifestly\ngauge-invariant description. We study the simplest case with multiple breaking\npatterns, an $\\textrm{SU}(3)$ Yang-Mills theory coupled to a single scalar\n`Higgs' field in the adjoint representation, on the lattice. We find that only\none pattern remains at fixed parameters and gauge-fixing strategy, and that the\nassociated quantum effective potential emerges from a non-trivial interplay of\nmany aspects."
    },
    {
        "anchor": "Probability distribution functions in the finite density lattice QCD: We study the phase structure of QCD at high temperature and density by\nlattice QCD simulations adopting a histogram method. We try to solve the\nproblems which arise in the numerical study of the finite density QCD, focusing\non the probability distribution function (histogram). As a first step, we\ninvestigate the quark mass dependence and the chemical potential dependence of\nthe probability distribution function as a function of the Polyakov loop when\nall quark masses are sufficiently large, and study the properties of the\ndistribution function. The effect from the complex phase of the quark\ndeterminant is estimated explicitly. The shape of the distribution function\nchanges with the quark mass and the chemical potential. Through the shape of\nthe distribution, the critical surface which separates the first order\ntransition and crossover regions in the heavy quark region is determined for\nthe 2+1-flavor case.",
        "positive": "Calculating the Isgur-Wise Function on the Lattice: We calculate the Isgur-Wise function by measuring the heavy-heavy meson\ntransition matrix element on the lattice. The standard Wilson action is used\nfor both the heavy and light quarks. Our first numerical results are presented."
    },
    {
        "anchor": "Computing the nucleon sigma terms at the physical point: Nucleon sigma terms are quantities that play an important role in various\nareas: among others, they connect the pion-nucleon and the kaon-nucleon\namplitudes to the hadron spectrum and they are also relevant for the direct\ndetection of Dark Matter. We present preliminary results for the up-down and\nstrange sigma terms obtained from $N_f=2+1$ lattice simulations that are\nperformed at five lattice spacings and for pion masses all the way down to its\nphysical value.",
        "positive": "O(3) nonlinear sigma model in 1+1 dimensions with matrix product states: We numerically study the spectral properties, the entanglement and the\nzero-temperature phase structure at nonvanishing chemical potential of the O(3)\nnonlinear sigma model. Using matrix product states, a particular kind of\none-dimensional tensor network state, we show that we are able to reach the\nasymptotic scaling regime and to reproduce the analytical predictions for the\nmass gap at vanishing chemical potential. In addition, we study the scaling of\nthe entanglement entropy towards the continuum limit obtaining a central charge\nconsistent with 2. Moreover, our approach does not suffer from the sign problem\nand we also explore the phase structure of the model for nonzero chemical\npotential and map out the location of the transitions between different charge\nsectors with high precision."
    },
    {
        "anchor": "Multiparticle States and the Hadron Spectrum on the Lattice: The Clebsch-Gordan decomposition is calculated for direct products of the\nirreducible representations of the cubic space group. These results are used to\nidentify multiparticle states which appear in the hadron spectrum on the\nlattice. Consideration of the cubic space group indicates how combinations of\nboth zero momentum and non-zero momentum multiparticle states contribute to the\nspectrum.",
        "positive": "Vortex configurations in the large N limit: We study the properties of vortex-like configurations which are solutions of\nthe SU(N) Yang-Mills classical equations of motion. We show that these\nsolutions are concentrated along a two-dimensional wall with size growing with\nthe number of colors."
    },
    {
        "anchor": "Three-Dimensional SU(3) gauge theory and the Spatial String Tension of\n  the (3+1)-Dimensional Finite Temperature SU(3) Gauge Theory: We establish a close relation between the spatial string tension of the\n(3+1)-dimensional $SU(3)$ gauge theory at finite temperature ($\\sigma_s$) and\nthe string tension of the 3-dimensional $SU(3)$ gauge theory ($\\sigma_3$) which\nis similar to what has been found previously for $SU(2)$. We obtain\n$\\sqrt{\\sigma_3} = (0.554 \\pm 0.004) g_3^2$ and $\\sqrt{\\sigma_s} = (0.586 \\pm\n0.045)g^2(T) T$, respectively. For temperatures larger than twice the critical\ntemperature results are consistent with a temperature dependent coupling\nrunning according to the two-loop $\\beta$-function with $\\Lambda_T =\n0.118(36)T_c$.",
        "positive": "Form factors for B and B_s semileptonic decays with NRQCD/HISQ quarks: We discuss preliminaries of a calculation of the form factors for the\nsemileptonic decays B -> pi lv, B_s -> K lv, and B -> K ll. We simulate with\nNRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad\nconfigurations. The form factors are calculated over a range of momentum\ntransfer to allow determination of their shape and the extraction of |V_ub|.\nAdditionally, we are calculating ratios of these form factors to those for the\nunphysical decay B_s -> eta_s. We are studying the possibility of combining\nthese precisely determined ratios with future calculations of B_s ->eta_s using\nHISQ b-quarks to generate form factors with significantly reduced errors."
    },
    {
        "anchor": "The Phase Diagram of Crystalline Surfaces: We report the status of a high-statistics Monte Carlo simulation of\nnon-self-avoiding crystalline surfaces with extrinsic curvature on lattices of\nsize up to $128^2$ nodes. We impose free boundary conditions. The free energy\nis a gaussian spring tethering potential together with a normal-normal bending\nenergy. Particular emphasis is given to the behavior of the model in the cold\nphase where we measure the decay of the normal-normal correlation function.",
        "positive": "How to Put a Heavier Higgs on the Lattice: The cutoff dependence of the Scalar Sector of the Minimal Standard Model can\nresult in an increase of the existing triviality bound estimates of the Higgs\nmass. We present a large $N$ calculation and some preliminary N=4 results that\nsuggest that the increase can be as large as 30%, resulting to a bound of about\n850 G eV."
    },
    {
        "anchor": "The Coupled Cluster Method in Hamiltonian Lattice Field Theory: The coupled cluster or exp S form of the eigenvalue problem for lattice\nHamiltonian QCD (without quarks) is investigated. A new construction\nprescription is given for the calculation of the relevant coupled cluster\nmatrix elements with respect to an orthogonal and independent loop space basis.\nThe method avoids the explicit introduction of gauge group coupling\ncoefficients by mapping the eigenvalue problem onto a suitable set of character\nfunctions, which allows a simplified procedure. Using appropriate group\ntheoretical methods, we show that it is possible to set up the eigenvalue\nproblem for eigenstates having arbitrary lattice momentum and lattice angular\nmomentum.",
        "positive": "Kaon and D meson masses with N_f = 2+1+1 twisted mass lattice QCD: We discuss the computation of the kaon and D meson masses in the N_f = 2+1+1\ntwisted mass lattice QCD setup, where explicit heavy flavor and parity breaking\noccurs at finite lattice spacing. We present three methods suitable in this\ncontext and verify their consistency."
    },
    {
        "anchor": "Perturbative chiral violations for domain-wall QCD with improved gauge\n  actions: We investigate, in the framework of perturbation theory at finite $N_s$, the\neffectiveness of improved gauge actions in suppressing the chiral violations of\ndomain-wall fermions. Our calculations show substantial reductions of the\nresidual mass when it is compared at the same value of the gauge coupling, the\nlargest suppression being obtained when the DBW2 action is used. Similar\neffects can also be observed for a power-divergent mixing coefficient which is\nchirally suppressed. No significant reduction instead can be seen in the case\nof the difference between the vector and axial-vector renormalization constants\nwhen improved gauge actions are used in place of the plaquette action. We also\nfind that one-loop perturbation theory is not an adequate tool to carry out\ncomparisons at the same energy scale (of about 2 GeV), and in fact in this case\neven an enhancement of the chiral violations is frequently obtained.",
        "positive": "$\u039b$ parameter of the SU(3) Yang-Mills theory from the continuous\n  $\u03b2$ function: Nonperturbative determinations of the renormalization group $\\beta$ function\nare essential to connect lattice results to perturbative predictions of\nstrongly coupled gauge theories and to determine the $\\Lambda$ parameter or the\nstrong coupling constant. The continuous $\\beta$ function is very well suited\nfor this task because it is applicable both in the weakly coupled deconfined\nregime as well as the strongly coupled confined regime. Here we report on our\nresults for the $\\beta$ function of the pure gauge SU(3) Yang-Mills theory in\nthe gradient flow scheme. Our calculations cover the renormalized coupling\nrange $g^2_{\\textrm{GF}} \\sim 1.2 - 27$, allowing for a direct determination of\n$\\sqrt{8t_0} \\Lambda_{\\overline{\\textrm{MS}}}$ in this system. Our prediction,\n$\\sqrt{8 t_0} \\Lambda_{\\overline{\\textrm{MS}}}=0.622(10)$, is in good agreement\nwith recent direct determinations of this quantity."
    },
    {
        "anchor": "Kaon semileptonic decay form factors from N_f = 2 non-perturbatively\n  O(a)-improved Wilson fermions: We present first results from the QCDSF collaboration for the kaon\nsemileptonic decay form factors at zero momentum transfer, using two flavours\nof non-perturbatively O(a)-improved Wilson quarks. A lattice determination of\nthese form factors is of particular interest to improve the accuracy on the CKM\nmatrix element |V_us|. Calculations are performed on lattices with lattice\nspacing of about 0.08 fm with different values of light and strange quark\nmasses, which allows us to extrapolate to chiral limit. Employing double ratio\ntechniques, we are able to get small statistical errors.",
        "positive": "Expressing the three-particle finite-volume spectrum in terms of the\n  three-to-three scattering amplitude: In this article we complete our formalism relating the finite-volume energy\nspectrum of a scalar quantum field theory to the three-to-three scattering\namplitude, ${\\cal M}_3$. In previous work we found a quantization condition\nrelating the spectrum to a non-standard infinite-volume quantity, denoted\n${\\cal K}_{{\\rm df},3}$. Here we present the relation between ${\\cal K}_{{\\rm\ndf},3}$ and ${\\cal M}_3$. We then discuss briefly how our now completed\nformalism can be practically implemented to extract ${\\cal M}_3$ from the\nfinite-volume energy spectrum."
    },
    {
        "anchor": "Colorful plane vortices and Chiral Symmetry Breaking in $SU(2)$ Lattice\n  Gauge Theory: We investigate plane vortices with color structure. The topological charge\nand gauge action of such colorful plane vortices are studied in the continuum\nand on the lattice. These configurations are vacuum to vacuum transitions\nchanging the winding number between the two vacua, leading to a topological\ncharge $Q=-1$ in the continuum. After growing temporal extent of these\nvortices, the lattice topological charge approaches $-1$ and the index theorem\nis fulfilled. We analyze the low lying modes of the overlap Dirac operator in\nthe background of these colorful plane vortices and compare them with those of\nspherical vortices. They show characteristic properties for spontaneous chiral\nsymmetry breaking.",
        "positive": "Understanding Hadron Structure Using Lattice QCD: Numerical evaluation of the path integral for QCD on a discrete space-time\nlattice has been used to calculate ground state matrix elements specifying\nmoments of quark density and spin distributions. This talk will explain how\nthese matrix elements have been calculated in full QCD using dynamical quarks,\nshow how physical extrapolation to the chiral limit including the physics of\nthe pion cloud resolves previous apparent conflicts with experiment, and\ndescribe the computational resources required for a definitive comparison with\nexperiment."
    },
    {
        "anchor": "Color-flavor reflection in the continuum limit of two-dimensional\n  lattice gauge theories with scalar fields: We address the interplay between local and global symmetries in determining\nthe continuum limit of two-dimensional lattice scalar theories characterized by\n$SO(N_c)$ gauge symmetry and non-Abelian $O(N_f)$ global invariance. We argue\nthat, when a quartic interaction is present, the continuum limit of these model\ncorresponds in some cases to the gauged non-linear $\\sigma$ model field theory\nassociated with the real Grassmannian manifold $SO(N_f)/(SO(N_c)\\times\nSO(N_f-N_c)$), which is characterized by the invariance under the color-flavor\nreflection $N_c\\leftrightarrow N_f-N_c$. Monte Carlo simulations and\nFinite-Size Scaling analyses, performed for $N_f=7$ and several values of\n$N_c$, confirm the emergence of the color-flavor reflection symmetry in the\nscaling limit, and support the identification of the continuum limit.",
        "positive": "Conformal symmetry vs. chiral symmetry breaking in the SU(3) sextet\n  model: We present new results for the SU(3) \"sextet model\" with two flavors\ntransforming according to the two-index symmetric representation of the gauge\ngroup. The simulations are performed using unimproved Wilson fermions. We\nmeasure the meson and baryon spectrum of the theory for multiple bare quark\nmasses at two different lattice spacings. To address the pressing issue of\nwhether the model is inside or below the conformal window, we compare the\nspectrum to the expectations for a theory with spontaneous chiral symmetry\nbreaking and to those of an IR conformal theory. Regardless of the answer\n(conformal or chirally broken), the theory is a cornerstone in our\nunderstanding of near-conformal and composite dynamics, ranging from\nTechnicolor models to unparticle physics. It is also interesting for the\ncomposite dynamics of vector-like singlets with respect to the Standard Model\ninteractions."
    },
    {
        "anchor": "Two Particle States in a Box and the $s$-Matrix in Multi-Channel\n  Scattering: Using a quantum mechanical model, the exact energy eigenstates for\ntwo-particle two-channel scattering are studied in a cubic box with periodic\nboundary conditions.\n  A relation between the exact energy eigenvalue in the box and the two-channel\n$S$-matrix elements in the continuum is obtained. This result can be viewed as\na generalization of the well-known L\\\"uscher's formula which establishes a\nsimilar relation in elastic scattering.",
        "positive": "Glueball Spectrum with four light dynamical fermions: We perform a calculation of the glueball spectrum for $N_f=4$ degenerate\ndynamical fermions with masses corresponding to light pions. We do so by making\nuse of ensembles produced within the framework of maximally twisted fermions by\nthe Extended Twisted Mass Collaboration (ETMC). We obtain masses of states that\nfall into the irreducible representations of the octahedral group of rotations\nin combination with the quantum numbers of charge conjugation $C$ and parity\n$P$; the above quantum numbers result in 20 distinct irreducible\nrepresentations. We implement the Generalized Eigenvalue Problem (GEVP) using a\nbasis that consists only of gluonic operators. The purpose of this work is to\ninvestigate the effect of light dynamical quarks on the glueball spectrum and\nhow this compares to the statistically more accurate spectrum of $SU(3)$ pure\ngauge theory. Given that glueball states may have broad widths and thus need to\nbe disentangled from all the relevant mixings, we use large ensembles of the\norder of ${\\sim {~\\cal O}}(20 {\\rm K})$ configurations. Despite the large\nensembles, the statistical uncertainties allow us to extract the masses for\nonly a few irreducible representations; namely $A_1^{++}$, $A_1^{-+}$, $E^{++}$\nas well as $T_2^{++}$. The results for the scalar $A_1^{++}$ representation\nshow that an additional state appears as the lightest state in the scalar\n$A_1^{++}$ channel of the glueball spectrum, while the next two excited states\nare consistent with the lightest two states of the pure gauge theory. To\nfurther elucidate the nature of this additional state we perform a calculation\nusing $N_f=2+1+1$ configurations and this demonstrates that it possesses a\nlarge quark content. Finally, the ground states of the $E^{++}$ and $T_2^{++}$\ntensor channels and of the $A_1^{-+}$ pseudoscalar channel show, at most, minor\neffects due to the inclusion of dynamical quarks."
    },
    {
        "anchor": "Non leptonic two-body decay amplitudes from finite volume calculations: We discuss the quantization of the energy levels of two-particle scattering\nstates in a finite volume in the case of Bloch-type boundary conditions. A\ngeneralization of the Luescher quantization condition is obtained that can be\nused in order to calculate the scattering phases, resulting for example by the\nstrong elastic interaction of two pions, at fixed physical momentum transfers\non a sequence of volumes of growing sizes. We also give a generalization of the\nLellouch-Luescher formula to be used to extract the physical decay rate for a\nkaon decaying into two pions below the inelastic threshold from finite volume\ncalculations. The formula is valid up to corrections exponentially vanishing in\nthe volume. By using this formula the calculation can in principle be performed\non different finite volumes of growing sizes in order to keep under control the\ncorrections.",
        "positive": "Lattice Formulation of Two-Dimensional N=(2,2) SQCD with Exact\n  Supersymmetry: We construct a lattice model for two-dimensional N=(2,2) supersymmetric QCD\n(SQCD), with the matter multiplets belonging to the fundamental or\nanti-fundamental representation of the gauge group U(N) or SU(N). The\nconstruction is based on the topological field theory (twisted supercharge)\nformulation and exactly preserves one supercharge along the line of the papers\n[1]--[4] for pure supersymmetric Yang-Mills theories. In order to avoid the\nspecies doublers of the matter multiplets, we introduce the Wilson terms and\nthe model is defined for the case of the number of the fundamental matters\n(n_{+}) equal to that of the anti-fundamental matters (n_{-}). If some of the\nmatter multiplets decouple from the theory by sending the corresponding\nanti-holomorphic twisted masses to the infinity, we can analyze the general\nn_{+}\\neq n_{-} case, although the lattice model is defined for n_{+} =n_{-}.\nBy computing the anomaly of the U(1)_A R-symmetry in the lattice perturbation,\nwe see that the decoupling is achieved and the anomaly for n_{+}\\neq n_{-} is\ncorrectly obtained."
    },
    {
        "anchor": "First direct lattice calculation of the chiral perturbation theory\n  low-energy constant $\\ell_7$: We evaluate by means of lattice QCD calculations the low-energy constant\n$\\ell_{7}$ which parametrizes strong isospin effects at NLO in $\\rm{SU}(2)$\nchiral perturbation theory. Among all low-energy constants at NLO, $\\ell_{7}$\nis the one known less precisely, and its uncertainty is currently larger than\n$50\\%$. Our strategy is based on the RM123 approach in which the lattice\npath-integral is expanded in powers of the isospin breaking parameter $\\Delta\nm= (m_{d}-m_{u})/2$. In order to evaluate the relevant lattice correlators we\nmake use of the recently proposed rotated twisted-mass (RTM) scheme. Within the\nRM123 approach, it is possible to cleanly extract the value of $\\ell_{7}$ from\neither the pion mass splitting $M_{\\pi^{+}}-M_{\\pi^{0}}$ induced by strong\nisospin breaking at order $\\mathcal{O}\\left((\\Delta m)^{2}\\right)$ (mass\nmethod), or from the coupling of the neutral pion $\\pi^{0}$ to the isoscalar\noperator $\\left(\\bar{u}\\gamma_{5}u + \\bar{d}\\gamma_{5} d\\right)/\\sqrt{2}$ at\norder $\\mathcal{O}(\\Delta m)$ (matrix element method). In this pilot study we\nlimit the analysis to a single ensemble generated by the Extended Twisted Mass\nCollaboration (ETMC) with $N_{f}=2+1+1$ dynamical quark flavours, which\ncorresponds to a lattice spacing $a\\simeq 0.095~{\\rm fm}$ and to a pion mass\n$M_{\\pi}\\simeq 260~{\\rm MeV}$. We find that the matrix element method\noutperforms the mass method in terms of resulting statistical accuracy. Our\ndetermination, $\\ell_{7} = 2.5(1.4)\\times 10^{-3}$, is in agreement and\nimproves previous calculations.",
        "positive": "Reply to: `Comment on: \" 't Hooft vertices, partial quenching, and\n  rooted staggered QCD\" ': We reply to Creutz's comments on our paper \" 't Hooft vertices, partial\nquenching, and rooted staggered QCD.\" We show that his criticisms are incorrect\nand result from a misunderstanding both of our work, and of the related work of\nAdams."
    },
    {
        "anchor": "Bulk Thermodynamics of SU(N) Lattice Gauge Theories at Large-N: We present a study of bulk thermodynamical quantities in the deconfined phase\nof pure lattice SU(N) gauge theories. We find that the deficit in pressure and\nentropy with respect to their free-gas values, for N=4,8, is remarkably close\nto that of SU(3). Th is suggests that understanding the strongly interacting\nnature of the deconfined phase, which is crucial for RHIC physics, can be done\nat large N. There, different analytical approaches simplify or become soluble,\nand one can check their predictions and point to their important ingredients.",
        "positive": "A perturbative determination of the parameters of an anisotropic quark\n  action: The parameters of a 3+1 anisotropic quark action with Symanzik-improved glue\nare determined at 1-loop in perturbation theory."
    },
    {
        "anchor": "Evidence for a Bound H-dibaryon from Lattice QCD: We present evidence for the existence of a bound H-dibaryon, an I=0, J=0,\ns=-2 state with valence quark structure uuddss, at a pion mass of m_pi ~ 389\nMeV. Using the results of Lattice QCD calculations performed on four ensembles\nof anisotropic clover gauge-field configurations, with spatial extents of L ~\n2.0, 2.5, 3.0 and 3.9 fm at a spatial lattice spacing of b ~ 0.123 fm, we find\nan H-dibaryon bound by B = 16.6 +- 2.1 +- 4.6 MeV at a pion mass of m_pi ~ 389\nMeV.",
        "positive": "Lattice B-field correlators for heavy quarks: We analyze the color-magnetic (or \"$B$\") field two-point function that\nencodes the finite-mass correction to the heavy quark momentum diffusion\ncoefficient. The simulations are done on fine isotropic lattices in the\nquenched approximation at $1.5\\,T_c$, using a range of gradient flow times for\nnoise suppression and operator renormalization. The continuum extrapolation is\nperformed at fixed flow time followed by a second extrapolation to zero flow\ntime. Perturbative calculations to next-to-leading order of this correlation\nfunction, matching gradient-flowed correlators to MS-bar, are used to resolve\nnontrivial renormalization issues. We perform a spectral reconstruction based\non perturbative model fits to estimate the coefficient $\\kappa_B$ of the\nfinite-mass correction to the heavy quark momentum diffusion coefficient. The\napproach we present here yields high-precision data for the correlator with all\nrenormalization issues incorporated at next-to-leading order, and is also\napplicable for actions with dynamical fermions."
    },
    {
        "anchor": "Vacuum structure revealed by over-improved stout-link smearing compared\n  with the overlap analysis for quenched QCD: A detailed comparison is made between the topological structure of quenched\nQCD as revealed by the recently proposed over-improved stout-link smearing in\nconjunction with an improved gluonic definition of the topological density on\none hand and a similar analysis made possible by the overlap-fermionic\ntopological charge density both with and without variable ultraviolet cutoff\n$\\lambda_{cut}$. The matching is twofold, provided by fitting the\ndensity-density two-point functions on one hand and by a point-by-point fitting\nof the topological densities according to the two methods. We point out the\nsimilar cluster structure of the topological density for moderate smearing and\n$200 \\mathrm{MeV} < \\lambda_{cut} < 600 \\mathrm{MeV}$, respectively. We\ndemonstrate the relation of the gluonic topological density for extensive\nsmearing to the location of the overlap zero modes and the lowest overlap\nnon-zero mode as found for the unsmeared configurations.",
        "positive": "A physicist-friendly reformulation of the Atiyah-Patodi-Singer index and\n  its mathematical justification: The Atiyah-Patodi-Singer index theorem describes the bulk-edge correspondence\nof symmetry protected topological insulators. The mathematical setup for this\ntheorem is, however, not directly related to the physical fermion system, as it\nimposes on the fermion fields a non-local and unnatural boundary condition\nknown as the \"APS boundary condition\" by hand. In 2017, we showed that the same\ninteger as the APS index can be obtained from the $\\eta$ invariant of the\ndomain-wall Dirac operator. Recently we gave a mathematical proof that the\nequivalence is not a coincidence but generally true. In this contribution to\nthe proceedings of LATTICE 2019, we try to explain the whole story in a\nphysicist-friendly way."
    },
    {
        "anchor": "Coupled channel analysis of the rho meson decay in lattice QCD: We employ a variational basis with a number of $\\bar{q}q$ and $\\pi\\pi$\nlattice interpolating fields with quantum numbers of the $\\rho$ resonance to\nextract the discrete energy spectrum in a finite volume. In the elastic region,\nthis spectrum is related to the phase shift of the continuum scattering\namplitude by L\\\"uscher's formula and the relation allows the extraction of\nresonance parameters from the spectrum calculation. The simulations are\nperformed at three different total momenta of the coupled $\\bar q q-\\pi\\pi$\nsystem, which allows us to extract the p-wave scattering phase at five values\nof pion relative momenta near the resonance region. The effective range formula\ndescribes the phase-shift dependence nicely and we extract the resonance mass\n$m_\\rho=792(7)(8)$ MeV and the coupling $g_{\\rho\\pi\\pi}=5.13(20)$ at our\n$m_\\pi\\simeq 266 $MeV. The coupling $g_{\\rho\\pi\\pi}$ is directly related to the\nwidth of the $\\rho$ meson and our value is close to the value derived from the\nexperimental width. The simulations are performed using dynamical gauge\nconfigurations with two mass-degenerate flavors of tree-level improved\nclover-Wilson fermions. Correlation functions are calculated using the recently\nproposed distillation method with Laplacian Heaviside (LapH) smearing of\nquarks, which enables flexible calculations, in many cases with unprecedented\naccuracy.",
        "positive": "Gluon propagators in QC$_2$D at high baryon density: We study the transverse and longitudinal gluon propagators in the\nLandau-gauge lattice QCD with gauge group $SU(2)$ at nonzero quark chemical\npotential and zero temperature. We show that both propagators demonstrate\nsubstantial dependence on the quark chemical potential. This observation\ncontradicts to earlier findings by other groups."
    },
    {
        "anchor": "Charmonium at high temperature in two-flavor QCD: We compute charmonium spectral functions in 2-flavor QCD on anisotropic\nlattices using the maximum entropy method. Our results suggest that the S-waves\n(J/psi and eta_c) survive up to temperatures close to 2Tc, while the P-waves\n(chi_c0 and chi_c1) melt away below 1.2Tc.",
        "positive": "The study of the Three Nucleon Force in full QCD Lattice calculations: We study the three nucleon force in the triton channel using dynamical clover\nfermion lattice QCD. The Nambu-Bethe-Salpeter wave function is utilized to\nobtain the potentials among three nucleons. Since the straightforward\ncalculation is prohibitively expensive, two different frameworks are developed\nto meet the challenge. In the first method, we study the effective two nucleon\npotentials in the three nucleon system, where the differences between the\neffective two nucleon potentials and the genuine two nucleon potentials\ncorrespond to the three nucleon system effect, part of which is originated from\nthe three nucleon force. The calculation is performed using Nf=2 clover fermion\nat m(\\pi)= 1.13GeV generated by CP-PACS Collaboration, and Nf=2+1 clover\nfermion at m(\\pi)= 0.70, 0.57GeV generated by PACS-CS Collaboration. In the\nsecond method, we study the three nucleon system with 3D-configuration of\nnucleons fixed. This enables us to extract the three nucleon force directly, if\nboth of parity-even and parity-odd two nucleon potentials are provided. Since\nparity-odd two nucleon potentials are not available in lattice QCD at this\nmoment, we propose a new general procedure to identify the three nucleon force\nusing only parity-even two nucleon potentials. The calculation are performed\nwith Nf=2 clover fermion at m(\\pi)= 1.13GeV generated by CP-PACS Collaboration,\nemploying the linear setup for the 3D-configuration. Preliminary results for\nthe scalar/isoscalar three nucleon force are presented."
    },
    {
        "anchor": "Double Parton Distributions of the Pion: The effects of double hard interactions are no longer negligible at energy\nscales reached at the LHC. Double parton scattering (DPS) processes are often\ndescribed by taking the product of two single parton scattering processes\nassuming that interference effects are very small. We calculate four point\nfunctions (4pt-functions), which appear in the the DPS cross section, employing\nlattice techniques. We consider a pion at rest and test the validity of the\nafore-mentioned factorization assumption by convoluting two pion form factors\nand comparing the result to the 4pt data. For our calculations we use a $N_f =\n2$ gauge ensemble on a $40^3 \\times 64$ lattice, with lattice spacing $a =\n0.071$ fm and pion mass $m_{\\pi} = 288.8$ MeV.",
        "positive": "$|V_{cb}|$ from the $\\bar{B}^0 \\to D^{*+} \\ell^- \\bar\u03bd$ zero-recoil\n  form factor using $2+1+1$ flavour HISQ and NRQCD: We present the status of our ongoing calculation of the zero-recoil form\nfactor for the semileptonic decay $\\bar{B}^0\\rightarrow D^{*+}l^-\\bar{\\nu}$\nusing lattice QCD with 2+1+1 flavours of highly improved staggered quarks in\nthe sea (the MILC HISQ configurations) and using non-relativistic QCD for the\nbottom quark. We combine our result for $ F(1)$ with the latest HFAG average of\n$\\eta_{EW} F(1)|V_{cb}|$ to get a preliminary value for $|V_{cb}|$."
    },
    {
        "anchor": "A lattice model of heavy-light three-body system: We present a study of a $1+1$ dimensional heavy-light three-body system in\nfinite volume. The heavy-light system is simulated by a coupled-channel\n$\\phi^4$ type lattice model, and both ground state and excited states of\nmultiparticle energy spectra are measured on various lattices. The lattice\nsimulation data analysis is performed based on variational approach.",
        "positive": "The QCD phase transition with physical-mass, chiral quarks: We report on the first lattice calculation of the QCD phase transition using\nchiral fermions at physical values of the quark masses. This calculation uses\n2+1 quark flavors, spatial volumes between (4 fm$)^3$ and (11 fm$)^3$ and\ntemperatures between 139 and 196 MeV . Each temperature was calculated using a\nsingle lattice spacing corresponding to a temporal Euclidean extent of $N_t=8$.\nThe disconnected chiral susceptibility, $\\chi_{\\rm disc}$ shows a pronounced\npeak whose position and height depend sensitively on the quark mass. We find no\nmetastability in the region of the peak and a peak height which does not change\nwhen a 5 fm spatial extent is increased to 10 fm. Each result is strong\nevidence that the QCD ``phase transition'' is not first order but a continuous\ncross-over for $m_\\pi=135$ MeV. The peak location determines a pseudo-critical\ntemperature $T_c = 155(1)(8)$ MeV. Chiral $SU(2)_L\\times SU(2)_R$ symmetry is\nfully restored above 164 MeV, but anomalous $U(1)_A$ symmetry breaking is\nnon-zero above $T_c$ and vanishes as $T$ is increased to 196 MeV."
    },
    {
        "anchor": "(lambda Phi^4)_4 theory on the lattice: evidence for a non-trivial\n  rescaling of the scalar condensate: A lattice simulation in the broken phase of four-dimensional (lambda Phi^4)\ntheory in the Ising limit suggests that, in the continuum limit, the scalar\ncondensate rescales by a factor different from the conventional wavefunction\nrenormalization. Possible effects on the present bounds of the Higgs mass are\ndiscussed.",
        "positive": "Asymptotic Scaling, Casimir Scaling, and Center Vortices: We report on two recent developments in the center vortex theory of\nconfinement: (i) the asymptotic scaling of the vortex density, as measured in\nMonte Carlo simulations; and (ii) an explanation of Casimir scaling and the\nadjoint string tension, in terms of the center vortex mechanism."
    },
    {
        "anchor": "Dirac operator normality and chiral properties: Normality and $\\ga$-hermiticity are what gives rise to chiral properties and\nrules. The Ginsparg-Wilson (GW) relation is only one of the possible spectral\nconstraints. The sum rule for chiral differences of real modes has important\nconsequences. The alternative transformation of L\\\"uscher gives the same Ward\nidentity as the usual chiral one (if zero modes are properly treated). Imposing\nnormality on a general function of the hermitean Wilson-Dirac operator $H$\nleads at the same time to the GW relation and to the Neuberger operator.",
        "positive": "$SU(2N_F)$ symmetry of confinement in QCD and its observation at high\n  temperature: In this talk we first overview lattice results that have led to the\nobservation of new SU(2)_{CS} and SU(2N_F) symmetries upon artificial\ntruncation of the near-zero modes of the Dirac operator at zero temperature and\nat high temperature without any truncation. These symmetries are larger than\nthe chiral symmetry of the QCD Lagrangian and contain chiral symmetries\nSU(N_F)_L \\times SU(N_F)_R and U(1)_A as subgroups. In addition to the standard\nchiral transformations the SU(2)_{CS} and SU(2N_F) transformations mix the\nright- and left-handed components of the quark fields. It is a symmetry of the\nconfining chromo-electric interaction while the chromo-magnetic interaction\nmanifestly breaks it. Emergence of these symmetries upon truncation of the\nnear-zero modes of the Dirac operator at T=0 means that all effects of the\nchromo-magnetic interaction are located exclusively in the near-zero modes,\nwhile confining chromo-electric interaction is distributed among all modes.\nAppearance of these symmetries at high T, where the temperature suppresses the\nnear-zero modes, has radical implications because these symmetries are\nincompatible with the asymptotically free deconfined quarks at increasing\ntemperature. The elementary objects in the high-temperature phase of QCD should\nbe quarks bound by the pure chromo-electric field that is not accompanied by\nthe chromo-magnetic effects."
    },
    {
        "anchor": "The critical behavior of hadronic matter: Comparison of lattice and\n  bootstrap model calculations: Statistical bootstrap model and the related concept of the limiting\ntemperature begun the discussion about phase transitions in the hadronic\nmatter. This was also the origin of the quark-gluon plazma concept. We discuss\nhere to which extend lattice studies of QCD critical behavior at non-zero\nchemical potential are compatible with the statistical bootstrap model\ncalculations.",
        "positive": "Topological features of the deconfinement transition: The first order transition between the confining and the center symmetry\nbreaking phases of the SU(3) Yang-Mills theory is marked by discontinuities in\nvarious thermodynamics functions, such as the energy density or the value of\nthe Polyakov loop. We investigate the non-analytical behaviour of the\ntopological susceptibility and its higher cumulant around the transition\ntemperature and make the connection to the curvature of the phase diagram in\nthe $T-\\theta$ plane and to the latent heat."
    },
    {
        "anchor": "Spin Resolution of Glueballs in 2+1 Dimensional Lattice Gauge Theory: Conventional lattice gauge theory assigns the lowest spin compatible with the\nsymmetry channel of a given operator to the state coupling to that operator.\nOperators on a cubic lattice, however, are only defined on angles of pi/2,\nhence states with spin equal modulo 4 may overlap significantly. This paper\nexplores a new technique for generating lattice operators that may be placed\nonto the lattice at angles other than pi/2, thereby resolving this modulo 4\nambiguity. Calculations of the mass of states with spin equal t o 0, 2, and 4\nare performed in the positive parity and charge conjugation channe l and\ncompared to the spectrum from previous lattice calculations. These masses\ncompare well for spin 0 and 2, and for spin 4 the mass agrees with a state conv\nentionally assigned spin 0, raising the possibility of mis-identification of\nthe spin of states coupling to some traditional operators.",
        "positive": "New methods for B meson decay constants and form factors from lattice\n  NRQCD: We determine the normalisation of scalar and pseudoscalar current operators\nmade from non-relativistic $b$ quarks and Highly Improved Staggered light\nquarks in lattice Quantum Chromodynamics (QCD) through $\\mathcal{O}(\\alpha_s)$\nand $\\Lambda_{\\text{QCD}}/m_b$. We use matrix elements of these operators to\nextract $B$ meson decay constants and form factors, then compare to those\nobtained using the standard vector and axial-vector operators. This provides a\ntest of systematic errors in the lattice QCD determination of the $B$ meson\ndecay constants and form factors. We provide a new value for the $B$ and $B_s$\nmeson decay constants from lattice QCD calculations on ensembles that include\n$u$, $d$, $s$ and $c$ quarks in the sea and those which have the $u/d$ quark\nmass going down to its physical value. Our results are $f_B=0.196(6)$ GeV,\n$f_{B_s}=0.236(7)$ GeV and $f_{B_s}/f_B =1.207(7)$, agreeing well with earlier\nresults using the temporal axial current. By combining with these previous\nresults, we provide updated values of $f_B=0.190(4)$ GeV, $f_{B_s}=0.229(5)$\nGeV and $f_{B_s}/f_B = 1.206(5)$."
    },
    {
        "anchor": "Bethe-Salpeter amplitudes of Upsilons: Based on lattice non-relativistic QCD (NRQCD) studies we present results for\nBethe-Salpeter amplitudes for $\\Upsilon(1S)$, $\\Upsilon(2S)$ and $\\Upsilon(3S)$\nin vacuum as well as in quark-gluon plasma. Our study is based on 2+1 flavor\n$48^3 \\times 12$ lattices generated using the Highly Improved Staggered Quark\n(HISQ) action and with a pion mass of $161$ MeV. At zero temperature the\nBethe-Salpeter amplitudes follow the expectations based on non-relativistic\npotential models. At non-zero temperatures, the interpretation of\nBethe-Salpeter amplitudes turns out to be more nuanced, but consistent with our\nprevious lattice QCD study of excited Upsilons in quark-gluon plasma.",
        "positive": "Dynamical Mean Field Approximation Applied to Quantum Field Theory: We apply the Dynamical Mean Field (DMFT) approximation to the real, scalar\nphi^4 quantum field theory. By comparing to lattice Monte Carlo calculations,\nperturbation theory and standard mean field theory, we test the quality of the\napproximation in two, three, four and five dimensions. The quantities\nconsidered in these tests are the critical coupling for the transition to the\nordered phase and the associated critical exponents nu and beta. We also map\nout the phase diagram in four dimensions. In two and three dimensions, DMFT\nincorrectly predicts a first order phase transition for all bare quartic\ncouplings, which is problematic, because the second order nature of the phase\ntransition of lattice phi^4-theory is crucial for taking the continuum limit.\nNevertheless, by extrapolating the behaviour away from the phase transition,\none can obtain critical couplings and critical exponents. They differ from\nthose of mean field theory and are much closer to the correct values. In four\ndimensions the transition is second order for small quartic couplings and turns\nweakly first order as the coupling increases beyond a tricritical value. In\ndimensions five and higher, DMFT gives qualitatively correct results, predicts\nreasonable values for the critical exponents and considerably more accurate\ncritical couplings than standard mean field theory. The approximation works\nbest for small values of the quartic coupling. We investigate the change from\nfirst to second order transition in the local limit of DMFT which is\ncomputationally much less intensive. We also discuss technical issues related\nto the convergence of the non-linear self-consistency equation solver and the\nsolution of the effective single-site model using Fourier-space Monte Carlo\nupdates in the presence of a phi^4-interaction."
    },
    {
        "anchor": "Dual lattice simulations of flux tubes: Abelian gauge theories formulated on a space-time lattice can be used as a\nprototype for investigating the confinement mechanism. In U(1) lattice gauge\ntheory it is possible to perform a dual transformation of the path integral.\nSimulating the obtained dual theory (which corresponds to a certain limit of a\ndual Higgs model) including external sources, we perform a very accurate\nanalysis of flux tubes with respect to the dual superconductor picture. Dual\nflux tube simulations are also performed in the full Abelian Higgs model, in\norder to obtain non-perturbative control over quantum and string fluctuations,\nand for a comparison to the results of dual QCD.",
        "positive": "The Quark Structure of Pentaquarks: Motivated by the possible observation of the $\\Theta^+(1530)$, we study the\nquark structure of pentaquark states in quenched lattice QCD. The complete set\nof 19 local sources that have the proper symmetry for positive or negative\nparity isoscalar pentaquarks is constructed, as well as a nonlocal source\ncomposed of two displaced ``good'' diquarks. Quantitative structure information\nis determined from diagonalizing the 19-dimensional correlation matrix and from\ncalculating the overlaps of sources with the lattice eigenstates. The volume\ndependence of the overlap is studied to differentiate between scattering and\nlocalized resonant states. The positive parity state has a small component of\ntwo ``good'' diquarks, and its energy is too much higher than the negative\nparity state to be a candidate for the $\\Theta^+(1530)$."
    },
    {
        "anchor": "Hopping Parameter Analysis of Leptonic and Semi-Leptonic Heavy-Light\n  Decays: We study leptonic and semi-leptonic decays of D and B mesons. Use of the\nHopping Parameter Expansion (HPE) for two-point functions allows us\ncontinuously to vary the pseudoscalar mass from below m_D up towards m_B. We\ncompute the pseudoscalar decay constants f_D and f_B, and observe consistency\nwith the value calculated in the static limit. {}From the measurement of\nthree-point functions we compute the matrix element relevant to the decay \\bar\nB -> D l \\bar nu_l and extract the Isgur-Wise function xi(v.v'). The HPE\nenables us freely to vary the initial state pseudoscalar mass at constant v.v',\nand we investigate the 1/m_Q corrections to the heavy-quark limit.",
        "positive": "Hamiltonian formalism in a problem of 3-th waves hierarchy: By the method of discrete transformation equations of 3-th wave hierarchy are\nconstructed. We present in explicit form two Poisson structures, which allow to\nconstruct Hamiltonian operator consequent application of which leads to all\nequations of this hierarchy. For calculations it will be necessary results of\nprevious paper \\cite{1}, which for convenience of the reader we present in\ncorresponding place of the text. The obtained formulae are checked by\nindependent calculations."
    },
    {
        "anchor": "Kaon Weak Matrix Elements with Wilson Fermions: We present results of several numerical studies with Wilson fermions relevant\nfor kaon physics. We compute the B_K parameter by using two different methods\nand extrapolate to the continuum limit. Our preliminary result is B_K(2\nGeV)=0.66(7). Delta I=3/2 K->pi pi matrix elements are obtained by using the\nnext-to-leading order expressions derived in chiral perturbation theory in\nwhich the low energy constants are determined by the lattice results computed\nat unphysical kinematics. From the simulation at beta=6.0 our (preliminary)\nresults read: <pi pi|O_7(2 GeV)|K>_{I=2}=0.14(1)(1) GeV^3 and <pi\npi|O_8(2GeV)|K>_{I=2}=0.69(6)(6) GeV^3.",
        "positive": "Lattice Determination of the $B^\\ast B \u03c0$ Coupling: The coupling $g_{B^\\ast B \\pi}$ is related to the form factor at zero\nmomentum of the axial current between $B^\\ast$ and $B$ states. Moreover it is\nrelated to the effective coupling between heavy mesons and pions that appear\nthe heavy meson chiral Lagrangian. This coupling has been evaluated on the\nlattice using static heavy quarks and light quark propagators determined by a\nstochastic inversion of the fermionic bilinear. We found the value\n$g=0.42(4)(8)$. Beside its theoretical interest, this quantity has\nphenomenological implications in $B \\to \\pi + \\bar l l$ decays."
    },
    {
        "anchor": "Gauge and matter fields as surfaces and loops - an exploratory lattice\n  study of the Z(3) Gauge-Higgs model: We discuss a representation of the Z(3) Gauge-Higgs lattice field theory at\nfinite density in terms of dual variables, i.e., loops of flux and surfaces. In\nthe dual representation the complex action problem of the conventional\nformulation is resolved and Monte Carlo simulations at arbitrary chemical\npotential become possible. A suitable algorithm based on plaquette occupation\nnumbers and link-fluxes is introduced and we analyze the model at zero\ntemperature and finite density both in the weak and strong coupling phases. We\nshow that at zero temperature the model has different first order phase\ntransitions as a function of the chemical potential both for the weak and\nstrong coupling phases. The exploratory study demonstrates that alternative\ndegrees of freedom may successfully be used for Monte Carlo simulations in\nseveral systems with gauge and matter fields.",
        "positive": "Electric and Magnetic Screening Masses at Finite Temperature from\n  Generalized Polyakov-Line Correlations in Two-flavor Lattice QCD: Screenings of the quark-gluon plasma in electric and magnetic sectors are\nstudied on the basis of generalized Polyakov-line correlation functions in\nlattice QCD simulations with two flavors of improved Wilson quarks. Using the\nEuclidean-time reflection ($\\R$) and the charge conjugation ($\\Ca$), electric\nand magnetic screening masses are extracted in a gauge invariant manner. Long\ndistance behavior of the standard Polyakov-line correlation in the quark-gluon\nplasma is found to be dictated by the magnetic screening. Also, ratio of the\ntwo screening masses agrees with that obtained from the dimensionally-reduced\neffective field theory and the ${\\cal N}=4$ supersymmetric Yang-Mills theory."
    },
    {
        "anchor": "The Lattice NJL Model at Non-zero Baryon and Isospin Densities: We present initial results of a numerical investigation of the chiral\nsymmetry restoring transition in the (3+1)-dimensional Nambu -- Jona-Lasinio\nmodel with both non-zero baryon chemical potential (mu_B) and isospin chemical\npotential (mu_I). With non-zero isospin chemical potential, the model suffers\nfrom a sign problem. We proceed in two ways: (i) We perform ``partially\nquenched'' simulations in which mu_I is made non-zero only during the\nmeasurement of chiral observables; (ii) We perform full simulations with\nimaginary isospin chemical potential with the aim to analytically continue\nresults to real mu_I.",
        "positive": "Effective $\\mathbb{Z}_{3}$ model for finite-density QCD with tensor\n  networks: The tensor renormalization group is a promising numerical method used to\nstudy lattice statistical field theories. However, this approach is\ncomputationally expensive in 2+1 and 3+1 dimensions. Here we use tensor\nrenormalization group methods to study an effective three-dimensional\n$\\mathbb{Z}_{3}$ model for the heavy-quark, high-temperature, strong-coupling\nlimit of single-flavor 3+1 dimensional quantum chromodynamics. Our results are\ncross-checked using the worm Monte Carlo algorithm. We present the phase\ndiagram of the model through the measurement of the Polyakov loop, the\nnearest-neighbor Polyakov loop correlator, and their susceptibilities. The\ntensor renormalization group results are in good agreement with the literature"
    },
    {
        "anchor": "Non-perturbative Renormalization of Improved Staggered Bilinears: We compute Z-factors for general staggered bilinears on fine (a \\approx 0.09\nfm) MILC ensembles using both asqtad and HYP-smeared valence actions, comparing\nthe results to the predictions of one-loop perturbation theory. This is an\nextension of previous work on the coarse (a \\approx 0.12 fm) MILC ensembles. It\nprovides a laboratory for studying NPR methodology in the staggered context,\nand is an important stepping stone for fully non-perturbative matching factors\nin ongoing computations of B_K and other weak matrix elements. We also\nimplement non-exceptional RI/SMOM renormalization conditions using the asqtad\naction and present first results.",
        "positive": "Lattice formulation of two-dimensional N=(2,2) super Yang-Mills with\n  SU(N) gauge group: We propose a lattice model for two-dimensional SU(N) N=(2,2) super Yang-Mills\nmodel. We start from the CKKU model for this system, which is valid only for\nU(N) gauge group. We give a reduction of U(1) part keeping a part of\nsupersymmetry. In order to suppress artifact vacua, we use an admissibility\ncondition."
    },
    {
        "anchor": "SU(N) gauge theories in 2+1 dimensions: glueball spectra and k-string\n  tensions: We calculate the low-lying glueball spectrum and various string tensions in\nSU(N) lattice gauge theories in 2+1 dimensions, and extrapolate the results to\nthe continuum limit. We do so for for the range N=2 to N=16 so as to control\nthe N-dependence with a useful precision. We observe a number of striking\nnear-degeneracies in the various J^PC sectors of the glueball spectrum, in\nparticular between C=+ and C=- states. We calculate the string tensions of flux\ntubes in a number of representations, and provide evidence that the leading\ncorrection to the N-dependence of the k-string tensions varies as 1/N rather\nthan 1/N^2, and that the dominant binding of k fundamental flux tubes into a\nk-string is via pairwise interactions. We comment on the possible implications\nof our results for the dynamics of these gauge theories.",
        "positive": "Latent heat and pressure gap at the first-order deconfining phase\n  transition of SU(3) Yang-Mills theory using the small flow-time expansion\n  method: We study the latent heat and the pressure gap between the hot and cold phases\nat the first-order transition temperature $T=T_c$ of SU(3) Yang-Mills theory,\nusing the small flow-time expansion (SF$t$X) method based on the gradient flow.\nWe first examine alternative procedures in the SFtX method -- the order of the\ncontinuum and vanishing flow-time extrapolations. We confirm that the final\nresults adopting the two orders, as well as other alternatives in which the\nperturbative order of the matching coefficients and the renormalization scale\nof the flow scheme are varied, are all consistent with each other. We also\nconfirm $\\Delta p$ is consistent with zero, as expected from the dynamical\nbalance of two phases at $T_c$. For the latent heat in the continuum limit, we\nfind $\\Delta \\epsilon /T^4 = 1.117(40)$ for the spatial volume $L^3$\ncorresponding to the aspect ratio $N_s/N_t=T_cL=8$ and $1.349(38)$ for\n$N_s/N_t=6$. From hysteresis curves, we show that the entropy density in the\nhot phase is sensitive to the spatial volume, while that in the confined phase\nis insensitive."
    },
    {
        "anchor": "Maximum entropy analysis of hadron spectral functions and excited states\n  in quenched lattice QCD: Employing the maximum entropy method we extract the spectral functions from\nmeson correlators at four lattice spacings in quenched QCD with the Wilson\nquark action. We confirm that the masses and decay constants, obtained from the\nposition and the area of peaks, agree well with the results from the\nconventional exponential fit. For the first excited state, we obtain $m_{\\pi_1}\n= 660(590)$ MeV, $m_{\\rho_1} = 1540(570)$ MeV, and $f_{\\rho_1} = 0.085(36)$ in\nthe continuum limit.",
        "positive": "$\u03b7^\\prime$ meson mass from topological charge density correlator in\n  QCD: The flavor-singlet component of the eta prime meson is related to the\ntopological structure of the SU(3) gauge field through the chiral anomaly. We\nperform a 2+1-flavor lattice QCD calculation and demonstrate that the two-point\nfunction of a gluonically defined topological charge density after a short\nYang-Mills gradient flow contains the propagation of the eta prime meson, by\nshowing that its mass in the chiral and continuum limit is consistent with the\nexperimental value. The gluonic correlator does not suffer from the\ncontamination of the pion contribution, and the clean signal is obtained at\nsignificantly lower numerical cost compared to the conventional method with the\nquark bilinear operators."
    },
    {
        "anchor": "Pion physics on the lattice: Recent results on pion physics from lattice QCD are reviewed. We discuss\nquark mass dependences of pion mass and decay constant and compare them with\nthe predictions from chiral perturbation theory. In particular we focus on the\nconvergence of chiral perturbation theory around strange quark mass region. We\nalso consider quark mass as well as momentum dependences of pion form factors\nin recent full QCD simulations.",
        "positive": "Non-lattice simulation of supersymmetric gauge theories as a probe to\n  quantum black holes and strings: In the past decade we have witnessed remarkable developments in the\ngauge-gravity duality, which suggested a new approach to superstring theory and\nquantum space-time. In this context it is important to study supersymmetric\nlarge-N gauge theories in the strongly coupled regime. I will summarize the\nresults and insights obtained so far by non-lattice simulations. A simple\nexample of the gauge-gravity duality is the one between 1d U(N) gauge theory\nwith 16 supercharges and the so-called black 0-brane solution in type IIA\nsupergravity. In order for this duality to be valid, one has to take the 't\nHooft large-N limit and to take the strong coupling limit on the gauge theory\nside. The gauge theory can be regularized by fixing the gauge completely thanks\nto one dimension, and by introducing a Fourier mode cutoff. One can then use\nthe standard RHMC algorithm to simulate the system. The energy calculated as a\nfunction of the temperature was compared with the results obtained from the\ngravity side based on the black hole thermodynamics. This confirmed the\ngauge-gravity duality with high accuracy and provided the microscopic origin of\nthe black hole thermodynamics. From the calculation of the Wilson loop, one\nobtains the Schwarzschild radius of the dual geometry. One can actually use the\npresent 1d model with supersymmetric mass deformation to study \\mathcal{N}=4\nsuper Yang-Mills theory on R \\times S^3 based on a novel large-N reduction,\nwhich generalizes the original idea of Eguchi and Kawai. It is remarkable that\nwe can now simulate the 4d superconformal field theory, which appears in the\nmost typical case of the gauge-gravity duality known as the AdS/CFT\ncorrespondence. In particular, no fine-tuning is required unlike previous\nproposals based on the lattice regularization."
    },
    {
        "anchor": "Volume Dependence of Bound States with Angular Momentum: We derive general results for the mass shift of bound states with angular\nmomentum l >= 1 in a finite periodic volume. Our results have direct\napplications to lattice simulations of hadronic molecules as well as atomic\nnuclei. While the binding of S-wave bound states increases at finite volume, we\nshow that the binding of P-wave bound states decreases. The mass shift for\nD-wave bound states as well as higher partial waves depends on the\nrepresentation of the cubic rotation group. Nevertheless, the\nmultiplet-averaged mass shift for any angular momentum l can be expressed in a\nsimple form, and the sign of the shift alternates for even and odd l. We verify\nour analytical results with explicit numerical calculations. We also show\nnumerically that similar volume corrections appear in three-body bound states.",
        "positive": "Two-particle Correlation Functions with Distilled Propagators: Correlation functions of the simplest multi-particle state will be presented\nusing distilled quark propagators. The I=2 pi-pi state can be simulated without\ncomputing disconnected diagrams and thus is the simplest two-particle state\nthat can be studied with quark sources placed on a single time-slice. We study\nthe quality of the signals of this pi-pi correlation function using the\nquark-smearing guided distillation method. Results will be presented for pi-pi\ncorrelation functions computed on dynamical, anisotropic lattices."
    },
    {
        "anchor": "Equation of State of dense QCD in external magnetic field: In this proceeding we present our first results of the study of the QCD\nEquation of State at non-zero baryon density and in external magnetic field. We\nfocused on the first three non-vanishing expansion coefficients of pressure in\nchemical potential and their dependence on magnetic field. The study is carried\nout within lattice simulations with $N_f=2+1$ dynamical quarks with physical\nquark masses. To overcome the sign problem, the simulations are carried out at\nimaginary baryon chemical potential. Our results suggest that external magnetic\nfield considerably enhances the expansion coefficients and modifies their\ndependence on temperature.",
        "positive": "SU(4) pure-gauge string tensions: In response to recently renewed interests in SU(N) pure-gauge dynamics with\nlarge N, both from M/string duality and from finite-temperature QCD phase\nstructure, we calculate string tensions acting between the fundamental 4,\ndiquark 6 and other color charges in SU(4) pure-gauge theory at temperatures\nbelow the deconfining phase change and above the bulk phase transition. Our\nresults suggest 4 and 6 representations have different string tensions, with a\nratio of about 1.3. We also found the deconfining phase change is not strong."
    },
    {
        "anchor": "The electric dipole moment of the neutron from 2+1 flavor lattice QCD: We compute the electric dipole moment d_n of the neutron from a fully\ndynamical simulation of lattice QCD with 2+1 flavors of clover fermions and\nnonvanishing theta term. The latter is rotated into the pseudoscalar density in\nthe fermionic action using the axial anomaly. To make the action real, the\nvacuum angle theta is taken to be purely imaginary. The physical value of d_n\nis obtained by analytic continuation. We find d_n = -3.8(2)(9) x 10^{-16}\n[theta e cm], which, when combined with the experimental limit on d_n, leads to\nthe upper bound theta < 7.6 x 10^{-11}.",
        "positive": "SO(3) vortices as a mechanism for generating a mass gap in the 2d SU(2)\n  principal chiral model: We propose a mechanism that can create a mass gap in the SU(2) chiral spin\nmodel at arbitrarily small temperatures. We give a sufficient condition for the\nmass gap to be non-zero in terms of the behaviour of an external Z(2) flux\nintroduced by twisted boundary conditions. This condition in turn is\ntransformed into an effective dual Ising model with an external magnetic field\ngenerated by SO(3) vortices. We show that having a nonzero magnetic field in\nthe effective Ising model is sufficient for the SU(2) system to have a mass\ngap. We also show that certain vortex correlation inequalities, if satisfied,\nwould imply a nonzero effective magnetic field. Finally we give some\nplausibility arguments and Monte Carlo evidence for the required correlation\ninequalities."
    },
    {
        "anchor": "Confining Strings and Glueballs in $\\mathbb{Z}_N$ Gauge Theories: Effective string theory has shown its universal power in the prediction of\nthe spectrum of low-lying excited states of confining strings. Here we study\nconfining flux tubes in $\\mathbb{Z}_N$ gauge theories. For the $N=2$ theory,\nwhich corresponds to the 3d Ising gauge model, we compute the spectrum of\nlow-lying excitations of confining strings and show that it agrees with the\nuniversal Nambu--Goto predictions except for an additional massive scalar\nresonance. This resonance, however, turns out to be a bulk glueball mixing with\nthe flux tube excitations rather than a genuine string worldsheet state. In\ngeneral $\\mathbb{Z}_N$ gauge theories (dual to clock spin models), we observe a\ncontinuous phase transition for $N \\geq 4$, while for $N > 5$ it is governed by\nthe $O(2)$ universality class. The critical behavior of the string tension and\nmass gap is verified to be described by a dangerously irrelevant operator. At\nlarge $N$ the glueball spectrum is expected to approach the spectrum of U(1)\ngauge theory, which is confirmed by our lattice data.",
        "positive": "From Decay to Complete Breaking: Pulling the Strings in SU(2) Yang-Mills\n  Theory: We study {2Q+1}-strings connecting two static charges Q in (2+1)-d SU(2)\nYang-Mills theory. While the fundamental {2}-string between two charges Q = 1/2\nis unbreakable, the adjoint {3}-string connecting two charges Q = 1 can break.\nWhen a {4}-string is stretched beyond a critical length, it decays into a\n{2}-string by gluon pair creation. When a {5}-string is stretched, it first\ndecays into a {3}-string, which eventually breaks completely. The energy of the\nscreened charges at the ends of a string is well described by a\nphenomenological constituent gluon model."
    },
    {
        "anchor": "Computational Methods for UV-Suppressed Fermions: Lattice fermions with suppressed high momentum modes solve the ultraviolet\nslowing down problem in lattice QCD. This paper describes a stochastic\nevaluation of the effective action of such fermions. The method is a based on\nthe Lanczos algorithm and it is shown to have the same complexity as in the\ncase of standard fermions.",
        "positive": "Transport coefficients of causal dissipative relativistic hydrodynamics\n  in quenched lattice simulations: Transport coefficients of causal dissipative relativistic fluid dynamics\n(CDR) are studied in quenched lattice simulations. CDR describes the behavior\nof relativistic non-Newtonian fluids in which the relaxation time appears as a\nnew transport coefficient besides the shear and bulk viscosities. It was\nrecently shown that these coefficients can be given by the temporal-correlation\nfunctions of the energy-momentum tensors as in the case of the\nGreen-Kubo-Nakano formula. By using the new formula in CDR, we study the\ntransport coefficients with lattice simulations in pure SU(3) gauge theory.\nAfter defining the energy-momentum tensor on the lattice, we extract a ratio of\nthe shear viscosity to the relaxation time which is given only in terms of the\nstatic correlation functions. The simulations are performed on $24^3 \\times\n4$--16 lattices with $\\beta_{_{\\rm LAT}} = 6.0$, which corresponds to the\ntemperature range of $0.5 \\simle T/T_c \\simle 1.8$, where $T_c$ is the critical\ntemperature."
    },
    {
        "anchor": "Bag representation for composite degrees of freedom in lattice gauge\n  theories with fermions: We explore new representations for lattice gauge theories with fermions,\nwhere the space-time lattice is divided into dynamically fluctuating regions,\ninside which different types of degrees of freedom are used in the path\nintegral. The first kind of regions is a union of so-called bags, in which the\ndynamics is described by the free propagation of composite degrees of freedom\nof the original fermions. In the second region, called complementary domain,\nconfigurations of the remaining interacting degrees of freedom are used to\ndescribe the dynamics. We work out the bag representation for the gauge groups\nSU(2) and SU(3) and address the nature of the strong coupling effective degrees\nof freedom, which are fermions for SU(3) and bosons for SU(2). We discuss first\nsteps towards a numerical simulation of the bag representations.",
        "positive": "An improved lattice measurement of the critical coupling in phi^4_2\n  theory: We use Monte Carlo simulations to obtain an improved lattice measurement of\nthe critical coupling constant [lambda / mu^2]_crit for the continuum (1 +\n1)-dimensional (lambda / 4) phi^4 theory. We find that the critical coupling\nconstant depends logarithmically on the lattice coupling, resulting in a\ncontinuum value of [lambda / mu^2]_crit = 10.8(1), in considerable disagreement\nwith the previously reported [lambda / mu^2]_crit = 10.26(8). Although this\nlogarithmic behavior was not observed in earlier lattice studies, it is\nconsistent with them, and expected analytically."
    },
    {
        "anchor": "Learning Trivializing Flows: The recent introduction of Machine Learning techniques, especially\nNormalizing Flows, for the sampling of lattice gauge theories has shed some\nhope on improving the sampling efficiency of the traditional Hybrid Monte Carlo\n(HMC) algorithm. In this work we study a modified HMC algorithm that draws on\nthe seminal work on trivializing flows by L\\\"uscher. Autocorrelations are\nreduced by sampling from a simpler action that is related to the original\naction by an invertible mapping realised through Normalizing Flows models with\na minimal set of training parameters. We test the algorithm in a $\\phi^{4}$\ntheory in 2D where we observe reduced autocorrelation times compared with HMC,\nand demonstrate that the training can be done at small unphysical volumes and\nused in physical conditions. We also study the scaling of the algorithm towards\nthe continuum limit under various assumptions on the network architecture.",
        "positive": "Lattice Determination of the Hadronic Contribution to the Muon $g-2$\n  using Dynamical Domain Wall Fermions: We present a calculation of the leading order hadronic contribution to the\nanomalous magnetic moment of the muon for a dynamical simulation of 2+1 flavour\nQCD using domain wall fermions. The electromagnetic 2-point function is\nevaluated on the RBC-UKQCD lattice gauge configurations and this is fitted to a\ncontinuous form motivated by models of vector dominance. We determine a robust\nand reliable technique for performing this fit, allowing us to extract the most\naccurate results possible from our ensembles. This combined with data at very\nlight quark masses produces the result a_\\mu^{(2)had}=641(33)(32) x 10^{-10} at\nthe physical point, where the first uncertainty is statistical, and the second\nis an estimate of systematics, which is in agreement with previous results. We\noutline various methods by which this calculation can and will be improved in\norder to compete with the accuracy of alternative techniques of deducing this\nquantity from experimental scattering data."
    },
    {
        "anchor": "Wilson versus Clover fermions: A case for improvement: We present evidence for improvement with tadpole improved clover fermions\nbased on an analysis of the chiral behavior of $B_K$ and the quark condensate.\nAlso presented are a comparison of the mass splittings in the baryon octet and\ndecuplet, a calculation of $c_A$ using standard 2-point correlation functions,\nand the problem of zero modes of the Dirac operator.",
        "positive": "A new dual representation for staggered lattice QCD: We propose a new strategy to evaluate the partition function of lattice QCD\nwith Wilson gauge action coupled to staggered fermions, based on a strong\ncoupling expansion in the inverse bare gauge coupling $\\beta= 2N/g^{2}$. Our\nmethod makes use of the recently developed formalism to evaluate the ${\\rm\nSU}(N)$ $1-$link integrals and consists in an exact rewriting of the partition\nfunction in terms of a set of additional dual degrees of freedom which we call\n\"Decoupling Operator Indices\" (DOI). The method is not limited to any\nparticular number of dimensions or gauge group ${\\rm U}(N)$, ${\\rm SU}(N)$. In\nterms of the DOI the system takes the form of a Tensor Network which can be\nsimulated using Worm-like algorithms. Higher order $\\beta$-corrections to\nstrong coupling lattice QCD can be, in principle, systematically evaluated,\nhelping to answer the question whether the finite density sign problem remains\nmild when plaquette contributions are included. Issues related to the\ncomplexity of the description and strategies for the stochastic evaluation of\nthe partition function are discussed."
    },
    {
        "anchor": "Infrared Renormalons and Finite Volume: We analyze the perturbative expansion of a condensate in the O(N) non-linear\nsigma model for large N on a two dimensional finite lattice. On an infinite\nvolume this expansion is affected by an infrared renormalon. We extrapolate\nthis analysis to the case of the gluon condensate of Yang-Mills theory and\nargue that infrared renormalons can be detected by performing perturbative\nstudies even on relatively small lattices.",
        "positive": "The Running Coupling from SU(3) Gauge Theory: We present high precision results on the static quark-antiquark-potential on\n32^4 and smaller lattices, using the standard Wilson action at BETA = 6.0, 6.2,\n6.4, and 6.8 on the Connection Machine CM-2. Within our statistical errors (1%)\nwe did not observe any finite size effects affecting the potential values, on\nvarying the spatial lattice extent from 0.9 fm up to 3.3 fm. We find violations\nof asymptotic scaling in the bare coupling up to BETA = 6.8. We demonstrate\nthat scaling violations on the string tension can be considerably reduced by\nintroducing effective coupling schemes, which allow for a safer extrapolation\nof LAMBDA_Lattice to its continuum value. We are also able to see and to\nquantify the running of the coupling from the interquark force. From this we\nextract the ratio \\sqrt{SIGMA}/LAMBDA_L. Both methods yield consistent values\nfor the LAMBDA-parameter: LAMBDA_MSbar = 0.558(-0.007+0.017)\\sqrt{SIGMA}\n  = 246(-3+7) MeV."
    },
    {
        "anchor": "Two-pion scattering amplitude from Bethe-Salpeter wave function at the\n  interaction boundary: We observe that the ratio of the on-shell scattering amplitude to the\nBethe-Salpeter (BS) wave function outside the interaction range is almost\nindependent of time in our quenched calculation of the $I=2$ two-pion\nscattering with almost zero momentum. In order to discuss the time\nindependence, we present a relation between the two-pion scattering amplitude\nand the surface term of the BS wave function at the boundary. Using the\nrelation under some assumptions, we show that the ratio is independent of time\nif the two-pion four-point function in early time is dominated by scattering\nstates with almost zero momentum in addition to the ground state of the\ntwo-pion scattering.",
        "positive": "Benchmark Test of CP-PACS for Lattice QCD: The CP-PACS is a massively parallel computer dedicated for calculations in\ncomputational physics and will be in operation in the spring of 1996 at Center\nfor Computational Physics, University of Tsukuba. In this article, we describe\nthe architecture of the CP-PACS and report the results of the estimate of the\nperformance of the CP-PACS for typical lattice QCD calculations."
    },
    {
        "anchor": "Multigrid Preconditioning for the Overlap Operator in Lattice QCD: The overlap operator is a lattice discretization of the Dirac operator of\nquantum chromodynamics, the fundamental physical theory of the strong\ninteraction between the quarks. As opposed to other discretizations it\npreserves the important physical property of chiral symmetry, at the expense of\nrequiring much more effort when solving systems with this operator. We present\na preconditioning technique based on another lattice discretization, the\nWilson-Dirac operator. The mathematical analysis precisely describes the effect\nof this preconditioning in the case that the Wilson-Dirac operator is normal.\nAlthough this is not exactly the case in realistic settings, we show that\ncurrent smearing techniques indeed drive the Wilson-Dirac operator towards\nnormality, thus providing a motivation why our preconditioner works well in\ncomputational practice. Results of numerical experiments in physically relevant\nsettings show that our preconditioning yields accelerations of up to one order\nof magnitude.",
        "positive": "Large-scale simulations with chiral symmetry: We carry out a comparative study among five-dimensional formulations of\nchirally symmetric fermions about the algorithmic performance, chiral symmetry\nviolation and topological tunneling to find a computationally inexpensive\nformulation with good chiral symmetry. With our choice of the lattice action,\nwe have launched large-scale simulations on fine lattices aiming at a precision\nstudy of light and heavy quark physics. We report on the comparative study,\ncurrent status of the large-scale simulations, and preliminary results on the\nresidual quark mass and auto-correlation."
    },
    {
        "anchor": "Higgs boson resonance parameters and the finite temperature phase\n  transition in a chirally invariant Higgs-Yukawa model: We study a chirally invariant Higgs-Yukawa model regulated on a space-time\nlattice. We calculate Higgs boson resonance parameters and mass bounds for\nvarious values of the mass of the degenerate fermion doublet. Also, first\nresults on the phase transition temperature are presented. In general, this\nmodel may be relevant for BSM scenarios with a heavy fourth generation of\nquarks.",
        "positive": "Asymptotically free lattice gauge theory in five dimensions: A lattice formulation of Lifshitz-type gauge theories is presented. While the\nLorentz-invariant Yang-Mills theory is not renormalizable in five dimensions,\nnon-Abelian Lifshitz-type gauge theories are renormalizable and asymptotically\nfree. We construct a lattice gauge action and numerically examine the continuum\nlimit and the bulk phase structure."
    },
    {
        "anchor": "QCD with dynamical Wilson fermions at $\u03b2=5.5$: We study QCD with two flavors of dynamical Wilson fermions at $\\beta = 5.5$\nand three values of $\\kappa$. The corresponding pion masses are 0.375, 0.324\nand 0.262 in lattice units, with pion to rho mass ratios of 0.76, 0.71 and\n0.62, respectively. We use the configurations to compute the heavy quark\npotential, leading to lattice spacings of 0.110, 0.105 and 0.099 fm, and to\ncompute spectroscopy for several different valence quark $\\kappa$'s.",
        "positive": "UV divergence of the quasi-PDF operator under the lattice regularization: Even since the \"quasi\" parton distribution function (PDF) was proposed under\nthe large-momentum effective theory (LaMET) framework, its renormalization\nunder the lattice regularization has been a central challenge to be solved due\nto the linear divergence. Thus, we investigate several possible ways to\nrenormalize the quasi-PDF operators in high accuracy with non-perturbative\ncalculation using the quench configurations at several lattice spacings. We\nfind that the ratio of the UV divergences obtained from the Wilson loop and\noff-shell quasi-PDF operator is not a constant of the Wilson link length $z$.\nAlthough the linear divergence in them may be consistent to each other\nnumerically, there is some additional UV divergence in the quasi-PDF operator."
    },
    {
        "anchor": "Baryon properties in meson mediums from lattice QCD: We present results for the ground-state mass shifts of octet baryons due to\nthe presence of a medium of pions or kaons from a lattice QCD calculation\nperformed at a single value of the quark mass, corresponding to a pion mass of\n$m_\\pi$ ~ 390 MeV, and a spatial volume V ~ (4fm)^3. We use a canonical\napproach in which correlators are formed using a single baryon propagator and a\nfixed number of meson propagators, up to n=9. From the ground-state energies we\ncalculate two- and three-body interaction parameters. We also extract\ncombinations of low-energy constants by comparing our results to tree level\nchiral perturbation theory at non-zero isospin/kaon chemical potential.",
        "positive": "The QCD Equation of State to $\\mathcal{O}(\u03bc_B^6)$ from Lattice QCD: We calculated the QCD equation of state using Taylor expansions that include\ncontributions from up to sixth order in the baryon, strangeness and electric\ncharge chemical potentials. Calculations have been performed with the Highly\nImproved Staggered Quark action in the temperature range $T\\in [135~{\\rm MeV},\n330~{\\rm MeV}]$ using up to four different sets of lattice cut-offs\ncorresponding to lattices of size $N_\\sigma^3\\times N_\\tau$ with aspect ratio\n$N_\\sigma/N_\\tau=4$ and $N_\\tau =6-16$. The strange quark mass is tuned to its\nphysical value and we use two strange to light quark mass ratios $m_s/m_l=20$\nand $27$, which in the continuum limit correspond to a pion mass of about $160$\nMeV and $140$ MeV espectively. Sixth-order results for Taylor expansion\ncoefficients are used to estimate truncation errors of the fourth-order\nexpansion. We show that truncation errors are small for baryon chemical\npotentials less then twice the temperature ($\\mu_B\\le 2T$). The fourth-order\nequation of state thus is suitable for the modeling of dense matter created in\nheavy ion collisions with center-of-mass energies down to $\\sqrt{s_{NN}}\\sim\n12$ GeV. We provide a parametrization of basic thermodynamic quantities that\ncan be readily used in hydrodynamic simulation codes. The results on up to\nsixth order expansion coefficients of bulk thermodynamics are used for the\ncalculation of lines of constant pressure, energy and entropy densities in the\n$T$-$\\mu_B$ plane and are compared with the crossover line for the QCD chiral\ntransition as well as with experimental results on freeze-out parameters in\nheavy ion collisions. These coefficients also provide estimates for the\nlocation of a possible critical point. We argue that results on sixth order\nexpansion coefficients disfavor the existence of a critical point in the QCD\nphase diagram for $\\mu_B/T\\le 2$ and $T/T_c(\\mu_B=0) > 0.9$."
    },
    {
        "anchor": "Deconfinement, chiral transition and localisation in a QCD-like model: We study the problems of deconfinement, chiral symmetry restoration and\nlocalisation of the low Dirac eigenmodes in a toy model of QCD, namely\nunimproved staggered fermions on lattices of temporal extension $N_T=4$. This\nmodel displays a genuine deconfining and chirally-restoring first-order phase\ntransition at some critical value of the gauge coupling. Our results indicate\nthat the onset of localisation of the lowest Dirac eigenmodes takes place at\nthe same critical coupling where the system undergoes the first-order phase\ntransition. This provides further evidence of the close relation between\ndeconfinement, chiral symmetry restoration and localisation of the low modes of\nthe Dirac operator on the lattice.",
        "positive": "Lattice calculation of medium effects at short and long distances: We investigate medium effects in QCD like chromoelectric screening and\nquasi-particle mass generation by calculating the heavy quark potential as well\nas the temporal quark and gluon Coulomb gauge propagators in quenched\napproximation."
    },
    {
        "anchor": "Chiral phase transition of $N_f$=2+1 and 3 QCD at vanishing baryon\n  chemical potential: We present updated results on chiral phase structure in (2+1)-flavor\n($N_f$=2+1) and 3-flavor ($N_f=3$) QCD based on the simulations using Highly\nImproved Staggered Quarks on lattices with temporal extent $N_\\tau$ =6 at\nvanishing baryon chemical potential. In $N_f$=2+1 QCD we have performed\nsimulations with a strange quark fixed to its physical value and two degenerate\nlight quarks whose values are adjusted to have 5 values of Goldstone pion\nmasses in the region of 160 - 80 MeV in the continuum limit. The universal\nscaling behavior of chiral condensates as well as chiral susceptibilities is\ndiscussed and the tri-critical point is suggested to be located below the\nphysical point, i.e. at smaller than physical strange quark mass. In $N_f$=3\nQCD simulations with 6 different masses of 3 degenerate quarks corresponding to\nthe Goldstone pion masses in the region of 230 - 80 MeV have also been\nperformed. Our results suggest that the QCD transition with these values of\nquark masses is of crossover type and an upper bound of the critical pion mass\nwhere the first order phase transition starts is estimated to be about 50 MeV.",
        "positive": "The critical behaviour of Ising spins on 2D Regge lattices: We performed a high statistics simulation of Ising spins coupled to 2D\nquantum gravity on toroidal geometries. The tori were triangulated using the\nRegge calculus approach and contained up to $512^2$ vertices. We used a\nconstant area ensemble with an added $R^2$ interaction term, employing the\n$dl/l$ measure. We find clear evidence that the critical exponents of the Ising\nphase transition are consistent with the static critical exponents and do not\ndepend on the coupling strength of the $R^2$ interaction term. We definitively\ncan exclude for this type of model a behaviour as predicted by Boulatov and\nKazakov [Phys. Lett. {\\bf B186}, 379 (1987)] for Ising spins coupled to\ndynamically triangulated surfaces."
    },
    {
        "anchor": "Excited State Effects in Nucleon Matrix Element Calculations: We perform a high-statistics precision calculation of nucleon matrix elements\nusing an open sink method allowing us to explore a wide range of sink-source\ntime separations. In this way the influence of excited states of nucleon matrix\nelements can be studied. As particular examples we present results for the\nnucleon axial charge $g_A$ and for the first moment of the isovector\nunpolarized parton distribution $<x>_{u-d}$. In addition, we report on\npreliminary results using the generalized eigenvalue method for nucleon matrix\nelements. All calculations are performed using $N_f=2+1+1$ maximally twisted\nmass Wilson fermions.",
        "positive": "Lattice QCD Impact on Determination of the CKM Matrix: We review many lattice QCD calculations that impact the precise determination\nof the CKM matrix. We focus on decay constants and semileptonic form factors of\nboth light ($\\pi$ and K) and heavy-light ($D_{(s)}$ and $B_{(s)}$) mesons.\nImplication of $\\Lambda_b$ form factors will be shown. When combined with\nexperimental results for branching fractions and differential decay rates, the\nabove calculations strongly constrain the first two rows of the CKM matrix. We\ndiscuss a long standing difference between $|V_{ub}|$ and $|V_{cb}|$ as\ndetermined from exclusive or inclusive decays."
    },
    {
        "anchor": "Update on Flavor Diagonal Nucleon Charges: This talk provides an update on the calculation of matrix elements of flavor\ndiagonal axial, scalar and tensor quark bilinear operators between the nucleon\nground state. The simulations are done using Wilson-clover fermions on a sea of\neight 2+1+1-flavor HISQ ensembles generated by the MILC collaboration. We\ndiscuss the signal in the sum of the connected and disconnected contributions\nfor the up, down and strange quarks, control over fits to remove excited state\ncontamination, and the simultaneous chiral-continuum fit used to extract the\ncharges.",
        "positive": "Confinement and monopole condensation: some properties of the disorder\n  parameter: We demonstrate that the disorder parameter $<\\mu>$ to detect dual\nsuperconductivity in the confining phase of QCD is the v.e.v. of a magnetically\ncharged, Dirac like, gauge invariant operator $\\mu$. We also show that the\nabelian projection on the lattice is determined up to terms O(a^2) (a = lattice\nspacing)."
    },
    {
        "anchor": "Quark Chromo-Electric Dipole Moment Operator on the Lattice: We present a lattice QCD study of the contribution of the isovector quark\nchromo-electric dipole moment (qcEDM) operator to the nucleon electric dipole\nmoments (nEDM). The calculation was carried out on four 2+1+1-flavor of highly\nimproved staggered quark (HISQ) ensembles using Wilson-clover quarks to\nconstruct correlation functions. This clover-on-HISQ formulation is not fully\n$O(a)$ improved, and gives rise to additional systematics over and above those\ndue to removing excited state contributions to getting ground-state matrix\nelements, and the final chiral and continuum extrapolations to get the physical\nresult. We use the non-singlet axial Ward identity including corrections up to\n$O(a)$ to show how to control the power-divergent mixing of the isovector qcEDM\noperator with the lower dimensional pseudoscalar operator. The residual\ncorrections are observed to give rise to $O(25\\%)$ violations in relations\narising from the axial Ward identity. We devise three methods attempting to\ncontrol the resulting uncertainty in the CP violating form factor; each of\nthese, however, can have large $O(a^2)$ corrections. Preliminary results for\nthe nEDM due to qcEDM are presented choosing the method giving the most uniform\nbehavior.",
        "positive": "Elastic Form Factors of Nucleon Excitations in Lattice QCD: First principles calculations of the form factors of baryon excitations are\nnow becoming accessible through advances in Lattice QCD techniques. In this\npaper, we explore the utility of the parity-expanded variational analysis\n(PEVA) technique in calculating the Sachs electromagnetic form factors for\nexcitations of the proton and neutron. We study the two lowest-lying odd-parity\nexcitations and demonstrate that at heavier quark masses, these states are\ndominated by behaviour consistent with constituent quark models for the\n$N^*(1535)$ and $N^*(1650)$, respectively. We also study the lowest-lying\nlocalised even-parity excitation, and find that its form factors are consistent\nwith a radial excitation of the ground state nucleon. A comparison of the\nresults from the PEVA technique with those from a conventional variational\nanalysis exposes the necessity of the PEVA approach in baryon excited-state\nstudies."
    },
    {
        "anchor": "Modified iterative versus Laplacian Landau gauge in compact U(1) theory: Compact U(1) theory in 4 dimensions is used to compare the modified iterative\nand the Laplacian fixing to lattice Landau gauge in a controlled setting, since\nin the Coulomb phase the lattice theory must reproduce the perturbative\nprediction. It turns out that on either side of the phase transition clear\ndifferences show up and in the Coulomb phase the ability to remove double Dirac\nsheets proves vital on a small lattice.",
        "positive": "The finite temperature QCD phase transition with domain wall fermions: Results from the Columbia lattice group study of the QCD finite temperature\nphase transition with dynamical domain wall fermions on $16^3 \\times 4$\nlattices are presented. These results include an investigation of the U(1)\naxial symmetry breaking above but close to the transition, the use of zero\ntemperature calculations that set the scale at the transition and preliminary\nmeasurements close to the transition."
    },
    {
        "anchor": "Building diquark model from Lattice QCD: A novel Lattice QCD (LQCD) method to determine the quark-diquark ($q$-$D$)\ninteraction potential together with the diquark mass ($m_D$) is proposed.\nSimilar to the HAL QCD method, $q$-$D$ potential is determined by demanding it\nto reproduce the $q$-$D$ equal-time Nambu-Bethe-Salpeter (NBS) wave function.\nTo do this, it is necessary to use the masses of the quark and the diquark as\ninputs, which however are not straightforwardly obtained because of the color\nconfinement of QCD. In this work, masses of quark and diquark are determined by\ndemanding that the p-wave spectrums from the two-point correlators be\nreproduced by the potentials for $c$-$\\bar{c}$ and $q$-$D$ sectors determined\nfrom the NBS wave functions. Numerical calculations are performed by using 2+1\nflavor QCD gauge configurations with the pion mass $m_\\pi\\simeq 700$ MeV\ngenerated by PACS-CS collaboration. We apply our method to the $c$-$\\bar c$\nsystem and the charm-diquark system ($\\Lambda_c$ baryon) to obtain the charm\nquark mass, diquark mass and the $c$-$D$ potential. Our preliminary analysis\nleads to the diquark mass $m_D \\simeq 1.127$ GeV which is roughly consistent\nwith a naive estimate based on the constituent quark picture, i.e., $m_{D}\n\\simeq m_{\\rho} \\simeq 1.12$ GeV and $m_{D} \\simeq 2m_N/3 \\simeq 1.06$ GeV.",
        "positive": "Progress in hadron structure physics on the lattice: This is a review of progress in hadron structure physics from lattice QCD.\nRecent results on the structure of the nucleon and the pion in terms of\n(transition) form factors, moments of distribution amplitudes and (generalized)\nparton distribution functions are presented. These observables allow us to\ninvestigate a number of fundamental physics questions related to e.g. the\ndistribution of charge and momentum in hadrons, the spin structure of the\nnucleon and the pion, and correlations between spin, orbital angular momentum\nand coordinate degrees of freedom. Chiral extrapolations of selected lattice\nresults are presented and compared to results from experiment and\nphenomenology. We conclude that lattice simulations already today strongly\ncontribute to our understanding of the structure of hadrons."
    },
    {
        "anchor": "The order of the deconfinement phase transition in a heavy quark mass\n  region: We study the quark mass dependence of the QCD phase transition by an\neffective potential defined through the distribution function of observables.\nAs a test of the method, we study the first order deconfinement phase\ntransition in the heavy quark mass limit and its fate at lighter quark masses.\nWe confirm that the distribution function for the plaquette has two peaks\nindicating that the phase transition is of first order in the heavy quark\nlimit. We then study the quark mass dependence of the distribution function by\na reweighting method combined with the hopping parameter expansion. We find\nthat the first order transition turns into a crossover as the quark mass\ndecreases. We determine the critical point for the cases of $N_f$=1, 2, 3 and\n2+1. We find that the probability distribution function provides us with a\npowerful tool to study the order of transitions.",
        "positive": "On the Eichten--Preskill Proposal for Lattice Chiral Gauge Theories: We have studied the Eichten--Preskill proposal for constructing lattice\nchiral gauge theories using both strong and weak coupling methods. The results\nindicate that this proposal is unlikely to work due to a dynamical behavior\nsimilar to that of the Smit--Swift proposal, which also does not give rise to\nchiral fermions."
    },
    {
        "anchor": "Non-perturbative scale evolution of four-fermion operators: We apply the Schroedinger Functional (SF) formalism to determine the\nrenormalisation group running of four-fermion operators which appear in the\neffective weak Hamiltonian of the Standard Model. Our calculations are done\nusing Wilson fermions and the parity-odd components of the operators.\nPreliminary results are presented for the operator $O_{VA}=(\\bar s \\gamma_\\mu\nd)(\\bar s \\gamma_\\mu \\gamma_5 d)$.",
        "positive": "Lattice QCD estimates of thermal photon production from the QGP: Thermal photons produced in heavy-ion collision experiments are an important\nobservable for understanding quark-gluon plasma (QGP). The thermal photon rate\nfrom the QGP at a given temperature can be calculated from the spectral\nfunction of the vector current correlator. Extraction of the spectral function\nfrom the lattice correlator is known to be an ill-conditioned problem, as there\nis no unique solution for a spectral function for a given lattice correlator\nwith statistical errors. The vector current correlator, on the other hand,\nreceives a large ultraviolet contribution from the vacuum, which makes the\nextraction of the thermal photon rate difficult from this channel. We therefore\nconsider the difference between the transverse and longitudinal part of the\nspectral function, only capturing the thermal contribution to the current\ncorrelator, simplifying the reconstruction significantly. The lattice\ncorrelator is calculated for light quarks in quenched QCD at $T=470~$MeV ($\\sim\n1.5\\, T_c$), as well as in 2+1 flavor QCD at $T=220~$MeV ($\\sim 1.2 \\, T_{pc}$)\nwith $m_{\\pi}=320$ MeV. In order to quantify the non-perturbative effects, the\nlattice correlator is compared with the corresponding\n$\\text{NLO}+\\text{LPM}^{\\text{LO}}$ estimate of correlator. The reconstruction\nof the spectral function is performed in several different frameworks, ranging\nfrom physics-informed models of the spectral function to more general models in\nthe Backus-Gilbert method and Gaussian Process regression. We find that the\nresulting photon rates agree within errors."
    },
    {
        "anchor": "Critical point phase transition for finite temperature 3-flavor QCD with\n  non-perturbatively O($a$) improved Wilson fermions at $N_{\\rm t}=10$: We study the finite temperature phase structure for three-flavor QCD with a\nfocus on locating the critical point which separates crossover and first order\nphase transition region in the chiral regime of the Columbia plot. In this\nstudy, we employ the Iwasaki gauge action and the non-perturvatively O($a$)\nimproved Wilson-Clover fermion action. We discuss the finite size scaling\nanalysis including the mixing of magnetization-like and energy-like\nobservables. We carry out the continuum extrapolation of the critical point\nusing newly generated data at $N_{\\rm t}=8$, $10$ and estimate the upper bound\nof the critical pseudo-scalar meson mass $m_{\\rm PS,E} \\lesssim 170 {\\rm MeV}$\nand the critical temperature $T_{\\rm E}=134(3){\\rm MeV}$. Our estimate of the\nupper bound is derived from the existence of the critical point as an edge of\nthe 1st order phase transition while that of the staggered-type fermions is\nbased on its absence.",
        "positive": "On meson spectral functions at high temperature and nonzero momentum: In the high-temperature phase of QCD meson spectral functions at nonzero\nmomentum are expected to have a nontrivial and interesting structure. In order\nto provide a reference point for lattice studies employing e.g. the Maximal\nEntropy Method, we discuss several characteristics of meson spectral functions\nin the infinite-temperature limit. We report on ongoing work in quenched QCD\nwith staggered fermions."
    },
    {
        "anchor": "Signatures of charmonium modification in spatial correlation functions: We study spatial correlation functions of charmonium in 2+1 flavor QCD using\nan improved staggered formulation. Contrary to the temporal correlation\nfunctions the spatial correlation functions exhibit a strong temperature\ndependence above the QCD transition temperature. Above this temperature they\nare sensitive to temporal boundary conditions. Both features become significant\nat a temperature close to 1.5 Tc and suggest corresponding modifications of\ncharmonium spectral functions.",
        "positive": "Two heavy-light mesons on a lattice: The potential between two heavy-light mesons as a function of the heavy quark\nseparation is calculated in quenched SU(3) lattice QCD. We study the case of\nheavy-light mesons with a static heavy quark and light quarks of mass close to\nthe strange quark mass. We explore the case of light quarks with the same and\nwith different flavours, classified according to the light quark isospin. We\nevaluate the appropriate light quark exchange contributions and explore the\nspin-dependence of the interaction. Comparison is made with meson exchange."
    },
    {
        "anchor": "Lattice energy-momentum tensor from the Yang-Mills gradient flow --\n  inclusion of fermion fields: Local products of fields deformed by the so-called Yang--Mills gradient flow\nbecome renormalized composite operators. This fact has been utilized to\nconstruct a correctly normalized conserved energy--momentum tensor in the\nlattice formulation of the pure Yang--Mills theory. In the present paper, this\nconstruction is further generalized for vector-like gauge theories containing\nfermions.",
        "positive": "Cutoff effects in the O(N) sigma model at large N: The computation of the step scaling function for the finite size mass-gap in\nthe O(N) sigma model at large N is reviewed. Practically exact nonperturbative\nresults become available for both finite and vanishing lattice spacing. We use\nthem as a testbed to investigate standard procedures of continuum extrapolation\nin lattice field theory."
    },
    {
        "anchor": "Transport Coefficients of Gluon Plasma: Transport coefficients of gluon plasma are calculated for a SU(3) pure gauge\nmodel by lattice QCD simulations on $16^3 \\times 8$ and $24^3 \\times 8$\nlattices. Simulations are carried out at a slightly above the deconfinement\ntransition temperature $T_c$, where a new state of matter is currently being\npursued in RHIC experiments. Our results show that the ratio of the shear\nviscosity to the entropy is less than one and the bulk viscosity is consistent\nwith zero in the region, $1.4 \\leq T/T_c \\leq 1.8 $.",
        "positive": "Renormalization-group analysis of the validity of staggered-fermion QCD\n  with the fourth-root recipe: I develop a renormalization-group blocking framework for lattice QCD with\nstaggered fermions. Under plausible, and testable, assumptions, I then argue\nthat the fourth-root recipe used in numerical simulations is valid in the\ncontinuum limit. The taste-symmetry violating terms, which give rise to\nnon-local effects in the fourth-root theory when the lattice spacing is\nnon-zero, vanish in the continuum limit. A key role is played by reweighted\ntheories that are local and renormalizable on the one hand, and that\napproximate the fourth-root theory better and better as the continuum limit is\napproached on the other hand."
    },
    {
        "anchor": "The Chiral Dirac Determinant According to the Overlap Formalism: The chiral Dirac determinant is calculated using the overlap formalism of\nNarayanan and Neuberger. We compare the real and imaginary parts of the\ndeterminant with the continuum result for perturbative gauge field backgrounds\nand show that they are identical. Thus we find that the overlap formalism\npasses a crucial test.",
        "positive": "Impact of stout-link smearing in lattice fermion actions: The impact of stout-link smearing in lattice fermion actions is examined\nthrough the consideration of the mass and renormalization functions of the\noverlap quark propagator over a variety of smeared configurations. Up to six\nsweeps of stout-link smearing are investigated. For heavy quark masses, the\nquark propagator is strongly affected by the smearing procedure. For moderate\nmasses, the effect appears to be negligible. A small effect is seen for light\nquark masses, where dynamical mass generation is suppressed through the\nsmearing procedure."
    },
    {
        "anchor": "A Polynomial Hybrid Monte Carlo Algorithm: We present a simulation algorithm for dynamical fermions that combines the\nmultiboson technique with the Hybrid Monte Carlo algorithm. We find that the\nalgorithm gives a substantial gain over the standard methods in practical\nsimulations. We point out the ability of the algorithm to treat fermion\nzeromodes in a clean and controllable manner.",
        "positive": "A study of the (m,d,N)=(1,3,2) Lifshitz point and of the three-\n  dimensional XY universality class by high-temperature bivariate series for\n  the XY models with anisotropic competing interactions: High-temperature bivariate expansions have been derived for the two-spin\ncorrelation-function in a variety of classical lattice XY (planar rotator)\nmodels in which spatially isotropic interactions among first-neighbor spins\ncompete with spatially isotropic or anisotropic (in particular uniaxial)\ninteractions among next-to-nearest-neighbor spins. The expansions, calculated\nfor cubic lattices of dimension d=1,2 and 3, are expressed in terms of the two\nvariables K1=J1/kT and K2=J2/kT, where J1 and J2 are the nearest-neighbor and\nthe next-to-nearest-neighbor exchange couplings, respectively. This report\ndeals in particular with the properties of the d=3 uniaxial XY model (ANNNXY\nmodel) for which the bivariate expansions have been computed through the 18-th\norder, thus extending by 12 orders the results so far available and making a\nstudy of this model possible over a wide range of values of the competition\nparameter R=J2/J1."
    },
    {
        "anchor": "$\u039e_c \u03b3\\rightarrow\u039e^\\prime_c$ transition in lattice QCD: We evaluate the electromagnetic $\\Xi_c \\gamma \\rightarrow\\Xi_c^\\prime$\ntransition on 2+1 flavor lattices corresponding to a pion mass of $\\sim 156$\nMeV. We extract the magnetic Sachs and Pauli form factors which give the\n$\\Xi_c$-$\\Xi_c^\\prime$ transition magnetic moment and the decay rates of\n$\\Xi_c^\\prime$ baryons. We did not find a signal for the magnetic form factor\nof the neutral transition $\\Xi_c^0 \\gamma \\rightarrow\\Xi_c^{\\prime 0}$, which\nis suppressed by the U-spin flavor symmetry. As a byproduct, we extract the\nmagnetic form factors and the magnetic moments of $\\Xi_c$ and $\\Xi_c^\\prime$\nbaryons, which give an insight to the dynamics of $u/d$, $s$ and $c$ quarks\nhaving masses at different scales.",
        "positive": "Flux representation of an effective Polyakov loop model for QCD\n  thermodynamics: We discuss an effective Polyakov loop model for QCD thermodynamics with a\nchemical potential. Using high temperature expansion techniques the partition\nsum is mapped exactly onto the partition sum of a flux model. In the flux\nrepresentation the complex action problem is resolved and a simulation with\nworm-type algorithms becomes possible also at finite chemical potential."
    },
    {
        "anchor": "Ginzburg Criterion for the Chiral Transition: This report is based on the work done together with J.B. Kogut and C.G.\nStrouthos. We study a Yukawa theory with spontaneous chiral symmetry breaking\nand with a large number N of fermions near the finite temperature phase\ntransition. Critical properties in such a system can be described by the mean\nfield theory very close to the transition point. We show that the width of the\nwindow of non-trivial scaling is suppressed by a certain power of 1/N. Our\nMonte Carlo simulations confirm these analytical results. We discuss\nimplications for the chiral phase transition in QCD.",
        "positive": "Glueballs and mesons in the superfluid phase of two-color QCD: QCD with two colors undergoes a transition to a superfluid phase with diquark\ncondensate when the quark chemical potential equals half the pion mass. We\ninvestigate the gluonic aspects of the transition by inspecting the behavior of\nthe glueball correlators evaluated via a multi-step smearing procedure for\nseveral values of chemical potential ranging between zero and the saturation\nthreshold. The results are based on an analysis of 0++ glueball correlators, on\na sample of 40000 independent configurations on each parameter set. The\namplitudes of the correlators peak for \\mu = m_\\pi/2,indicating that the\nsuperfluid phase transition affects the gluonic sector as well. The mass of the\nfundamental state decreases in the superfluid phase, and the amplitude of the\npropagators drops, suggesting a reduction of the gluon condensate, in agreement\nwith model calculations. The analysis of the smearing dependence of the results\nhelps disentangling the role of long and short distance phenomena at the\nsuperfluid transition."
    },
    {
        "anchor": "Efficiency of the UV-filtered Multiboson algorithm: We study the efficiency of an improved Multiboson algorithm with two flavours\nof Wilson fermions in a realistic physical situation ($\\beta = 5.60$, $\\kappa =\n0.156$ on a $16^3 \\times 24$ lattice). The performance of this exact algorithm\nis compared with that of a state-of-the-art HMC algorithm: a considerable\nimprovement is obtained for the plaquette auto-correlation time, while the two\nalgorithms appear similarly efficient at decorrelating the topological charge.",
        "positive": "Electromagnetic Splittings and Light Quark Masses in Lattice QCD: A method for computing electromagnetic properties of hadrons in lattice QCD\nis described and preliminary numerical results are presented. The\nelectromagnetic field is introduced dynamically, using a noncompact\nformulation. Employing enhanced electric charges, the dependence of the\npseudoscalar meson mass on the (anti)quark charges and masses can be accurately\ncalculated. At $\\beta=5.7$ with Wilson action, the $\\pi^+-\\pi^0$ splitting is\nfound to be $4.9(3)$ MeV. Using the measured $K^0-K^+$ splitting, we also find\n$m_u/m_d = .512(6)$. Systematic errors are discussed."
    },
    {
        "anchor": "The influence of gauge field smearing on discretisation effects: When designing lattice actions, gauge field smearing is frequently used to\ndefine the lattice Dirac operator. Since the smearing procedure removes effects\nof ultraviolet fluctuations, the fermions effectively see a larger lattice\nspacing than the gauge fields. Creutz ratios, formed from ratios of rectangular\nWilson loops, based on smeared gauge fields are adequate observables to\ninvestigate the effect of smearing since they do not need renormalisation and\nprovide a measure of the physical forces felt by the fermions. We study their\nbehaviour at various smearing radii (fixed in lattice units) and in particular\nhow the smearing influences the scaling towards the continuum limit. Since we\nemploy the Wilson gradient flow as smearing, the same Creutz ratios have\nanother, well defined continuum limit, when the flow time is fixed in physical\nunits. That continuum limit is reached with smaller corrections at finite $a$.",
        "positive": "Charmonium spectral functions in two-flavour QCD: We compute charmonium spectral functions in 2-flavour QCD using the maximum\nentropy method and anisotropic lattices. We find that the S-waves (J/psi and\neta_c) survive up to temperatures close to 2T_c, while the P-waves (chi_c0 and\nchi_c1) melt away below 1.3T_c."
    },
    {
        "anchor": "On Charmonia Survival Above Deconfinement: We study charmonium correlators and spectral functions at zero and finite\ntemperature using anisotropic lattices at several different lattice spacings.\nWe find evidence for survival of 1S charmonia states at leas till $1.5T_c$ and\ndissolution of 1P states at $1.16T_c$.",
        "positive": "QCD at non-zero temperature: bulk properties and heavy quarks: I review recent progress in lattice QCD at non-zero temperature whith\nemphasis on the calculations of equation of state and the properties of heavy\nquar anti-quark pairs at high temperatures. I also briefly discuss the\ndeconfinement and chiral symmetry restoring aspects of the QCD transition at\nfinite temperature"
    },
    {
        "anchor": "Structure and Representation Theory for Double Group of Four-Dimensional\n  Cubic Group: Hypercubic groups in any dimension are defined and their conjugate\nclassifications and representation theories are derived. Double group and\nspinor representation are introduced. A detailed calculation is carried out on\nthe structures of four-dimensional cubic group $O_4$ and its double group, as\nwell as all inequivalent single-valued representations and spinor\nrepresentations of $O_4$. All representations are derived adopting Clifford\ntheory of decomposition of induced representations. Based on these results,\nsingle-valued and spinor representations of the orientation-preserved subgroup\nof $O_4$ are calculated.",
        "positive": "Running coupling constant and correlation length from Wilson loops: We consider a definition of the QCD running coupling constant $\\alpha(\\mu)$\nrelated to Wilson loops of size $r{\\times}t$ with arbitrary fixed $t/r$. The\nschemes defined by these couplings are very close to the $\\overline{\\rm MS}$\nscheme for all values of $t/r$; in the $t/r\\to\\infty$ limit, the ``$q\\bar q$\nforce'' scheme is recovered. We propose a definition of correlation length,\nalso related to Wilson loops, which can be applied to the Monte Carlo\nevaluation of $\\alpha(\\mu)$ up to very large momentum scales by use of\nfinite-size scaling techniques."
    },
    {
        "anchor": "Light hadron masses with a tadpole-improved next-nearest-neighbour\n  lattice fermion action: Calculations of hadron masses are done in quenched approximation using gauge\nfield and fermion actions which are both corrected for discretization errors to\n$O(a^2)$ at the classical level and which contain tadpole improvement factors.\nThe fermion action has both nearest-neighbour and next-nearest-neighbour\ncouplings in the kinetic and Wilson terms. Simulations done at lattice spacings\nof $0.27$ and $0.4$fm yield hadron masses which are already quite close to\nexperimental values. The results are compared to Wilson action calculations\ndone at comparable lattice spacings.",
        "positive": "Equation of state from complex Langevin simulations: We use complex Langevin simulations to study the QCD phase diagram with two\nlight quark flavours. In this study, we use Wilson fermions with an\nintermediate pion mass of $\\sim480\\,$MeV. By studying thermodynamic quantities,\nin particular at lower temperatures, we are able to describe the equation of\nstate."
    },
    {
        "anchor": "Unconstrained Variables and Equivalence Relations for Lattice Gauge\n  Theories: We write the partition function for a lattice gauge theory, with compact\ngauge group, exactly in terms of unconstrained variables and show that, in the\nmean field approximation, the dynamics of pure gauge theories, invariant under\ncompact, continuous,groups of rank 1 is the same for all. We explicitly obtain\nthe equivalence for the case of SU(2) and U(1) and show that it obtains, also,\nif we consider saddle point configurations that are not,necessarily, uniform,\nbut only proportional to the identity for both groups. This implies that the\nphase diagrams of the (an)isotropic SU(2) theory and the (an)isotropic U(1)\ntheory in any dimension are identical, within this approximation, up to a\nre-evaluation of the numerical values of the coupling constants at the\ntransitions. Only nonuniform field configurations, that, also, belong to higher\ndimensional representations for Yang--Mills fields, will be able to p robe the\ndifference between them. We also show under what conditions the global symmetry\nof an anisotropic term in the lattice action can be promoted to a gauge\nsymmetry of the theory on layers and point out how deconstruction and flux\ncompactification scenaria may thus be studied on the lattice.",
        "positive": "Non-zero density QCD by the Taylor expansion method: The isentropic\n  equation of state, hadronic fluctuations and more: We discuss the Taylor expansion approach to non-zero baryon chemical\npotential ($\\mu_B$) and present results on expanion coefficients of the\npressure and energy density up to the 6-th order in $\\mu_B$. Calculations have\nbeen performed with (2+1)-flavor of improved staggerd fermions (p4fat3) and\nalmost physical masses on lattices with temporal extent of four and six time\nslices. We use the expansion coefficients to construct the isentropic equation\nof state on lines of constant entropy per baryon number and various different\nhadronic fluctuations. Furthermore, we estimate the radius of convegence of our\nexpansion, which can be seen as a method to analyze the structure of the QCD\nphase diagram."
    },
    {
        "anchor": "Direct computational approach to lattice supersymmetric quantum\n  mechanics: We propose a numerical method of estimating various physical quantities in\nlattice (supersymmetric) quantum mechanics. The method consists only of\ndeterministic processes such as computing a product of transfer matrix, and has\nno statistical uncertainties. We use the numerical quadrature to define the\ntransfer matrix as a finite dimensional matrix, and find that it effectively\nworks by rescaling variable for sufficiently small lattice spacings. For a\nlattice supersymmetric quantum mechanics, the correlators can be estimated\nwithout statistical errors, and the effective masses coincide with the exact\nsolution within very small errors less than 0.001%. The SUSY Ward identity is\nalso precisely studied in compared with the Monte-Carlo method. Our method is\nnot limited to a lattice SUSY quantum mechanics, but is also applicable to any\nother lattice models of quantum mechanics.",
        "positive": "Dynamical stabilisation of complex Langevin simulations of QCD: The ability to describe strongly interacting matter at finite temperature and\nbaryon density provides the means to determine, for instance, the equation of\nstate of QCD at non-zero baryon chemical potential. From a theoretical point of\nview, direct lattice simulations are hindered by the numerical sign problem,\nwhich prevents the use of traditional methods based on importance sampling.\nDespite recent successes, simulations using the complex Langevin method have\nbeen shown to exhibit instabilities, which cause convergence to wrong results.\nWe introduce and discuss the method of Dynamic Stabilisation (DS), a\nmodification of the complex Langevin process aimed at solving these\ninstabilities. We present results of DS being applied to the heavy-dense\napproximation of QCD, as well as QCD with staggered fermions at zero chemical\npotential and finite chemical potential at high temperature. Our findings show\nthat DS can successfully deal with the aforementioned instabilities, opening\nthe way for further progress."
    },
    {
        "anchor": "Charm quark system in 2+1 flavor lattice QCD using the PACS-CS\n  configurations: We study heavy-heavy and heavy-light quark systems for charm with a\nrelativistic heavy quark action in 2+1 flavor lattice QCD. Configurations are\ngenerated by the PACS-CS Collaboration at the lattice spacing is $a=0.09$ fm\nwith the lattice size of $32^3\\times 64$ employing the $O(a)$-improved Wilson\nquark action and the Iwasaki gauge action. We present preliminary results for\nthe charmonium spectrum and the $D$ and $D_s$ meson decay constants evaluated\nat 3.5 MeV$< m_{\\rm ud}<$ 12 MeV with $m_{\\rm s}$ around the physical value. We\ninvestigate the dynamical quark mass dependences of the hyperfine and the\norbital splittings. The decay constants are compared with the recent\nexperimental values.",
        "positive": "A Method to Calculate Conserved Currents and Fermionic Force for the\n  Lanczos Approximation to the Overlap Dirac Operator: The overlap Dirac operator obeys the Ginsparg-Wilson equation and offers a\npossibility to introduce chiral symmetry on the lattice. Evaluating the overlap\noperator is numerically very expensive and one has to rely on approximation\nmethods. At finite chemical potential the overlap operator can be efficiently\ncomputed with the two-sided Lanczos algorithm. To calculate conserved currents\non the lattice, or to evaluate the fermionic force in HMC calculations, one\nneeds to compute derivatives of the Dirac operator with respect to gauge\nfields. In this paper we present a method to simultaneously compute the action\nof the overlap operator and its derivative on a source vector."
    },
    {
        "anchor": "Covariant approximation averaging: We present a new class of statistical error reduction techniques for\nMonte-Carlo simulations. Using covariant symmetries, we show that correlation\nfunctions can be constructed from inexpensive approximations without\nintroducing any systematic bias in the final result. We introduce a new class\nof covariant approximation averaging techniques, known as all-mode averaging\n(AMA), in which the approximation takes account of contributions of all\neigenmodes through the inverse of the Dirac operator computed from the\nconjugate gradient method with a relaxed stopping condition. In this paper we\ncompare the performance and computational cost of our new method with\ntraditional methods using correlation functions and masses of the pion,\nnucleon, and vector meson in $N_f=2+1$ lattice QCD using domain-wall fermions.\nThis comparison indicates that AMA significantly reduces statistical errors in\nMonte-Carlo calculations over conventional methods for the same cost.",
        "positive": "Reweighting QCD simulations with dynamical overlap fermions: I apply a recently developed algorithm for reweighting simulations of lattice\nQCD from one quark mass to another to simulations performed with overlap\nfermions in the epsilon regime. I test it by computing the condensate from\ndistributions of the low lying eigenvalues of the Dirac operator. Results seem\nfavorable."
    },
    {
        "anchor": "No-Go Theorem of Leibniz Rule and Supersymmetry on the Lattice: An obstacle to realize supersymmetry on a lattice is the breakdown of Leibniz\nrule. We give a proof of a no-go theorem that it is impossible to construct a\nlattice field theory in an infinite lattice volume with any nontrivial field\nproducts and difference operators that satisfy the following three properties:\n(i) translation invariance, (ii) locality and (iii) Leibniz rule. We then\npropose a way to escape from the no-go theorem by introducing infinite flavors,\nand present a lattice model of N=2 supersymmetric quantum mechanics equipped\nwith the full exact supersymmetry.",
        "positive": "Tensor network approach to real-time path integral: We present a tensor network representation of the path integral for the\none-component real scalar field theory in 1+1 dimensional Minkowski space-time.\nIt is numerically verified by comparing with the exact result in the\nnon-interacting case."
    },
    {
        "anchor": "Nucleon structure in terms of OPE with non-perturbative Wilson\n  coefficients: Lattice calculations could boost our understanding of Deep Inelastic\nScattering by evaluating moments of the Nucleon Structure Functions. To this\nend we study the product of electromagnetic currents between quark states. The\nOperator Product Expansion (OPE) decomposes it into matrix elements of local\noperators (depending on the quark momenta) and Wilson coefficients (as\nfunctions of the larger photon momenta). For consistency with the matrix\nelements, we evaluate a set of Wilson coefficients non-perturbatively, based on\npropagators for numerous momentum sources, on a 24^3 x 48 lattice. The use of\noverlap quarks suppresses unwanted operator mixing and lattice artifacts.\nResults for the leading Wilson coefficients are extracted by means of Singular\nValue Decomposition.",
        "positive": "Heavy-quark physics with a tmQCD valence action: We introduce a mixed-action approach based on CLS ensembles, where a valence\n$N_f$=2+1+1 Twisted Mass QCD action is combined with the $N_f$=2+1\nnon-perturbatively O$(a)$-improved Wilson sea sector. We show that for\nmaximally twisted valence quarks, the automatic O$(a)$-improvement of this\nset-up holds up to lattice artifacts coming from sea quark mass effects.\nFurthermore, we introduce a three-dimensional Gradient Flow smearing in order\nto tame the signal to noise ratio problem."
    },
    {
        "anchor": "Atiyah-Patodi-Singer index theorem for domain-wall fermion Dirac\n  operator: Recently, the Atiyah-Patodi-Singer(APS) index theorem attracts attention for\nunderstanding physics on the surface of materials in topological phases.\nAlthough it is widely applied to physics, the mathematical set-up in the\noriginal APS index theorem is too abstract and general (allowing non-trivial\nmetric and so on) and also the connection between the APS boundary condition\nand the physical boundary condition on the surface of topological material is\nunclear. For this reason, in contrast to the Atiyah-Singer index theorem,\nderivation of the APS index theorem in physics language is still missing. In\nthis talk, we attempt to reformulate the APS index in a \"physicist-friendly\"\nway, similar to the Fujikawa method on closed manifolds, for our familiar\ndomain-wall fermion Dirac operator in a flat Euclidean space. We find that the\nAPS index is naturally embedded in the determinant of domain-wall fermions,\nrepresenting the so-called anomaly descent equations.",
        "positive": "Fractal Behaviour in the O(3) Model: We study domain formation in the two-dimensional O(3) model near criticality.\nThe fractal dimension of these domains is determined with good statistical\naccuracy."
    },
    {
        "anchor": "Finite Size Scaling for the O(N) universality class from Renormalization\n  Group Methods: The QCD phase diagram at finite temperature and density is a topic of\nconsiderable interest. Although much progress has been made in recent years,\nsome open questions remain. Even at zero density, the order of the transition\nfor two light flavors of fermions has not yet been conclusively established.\nWhile considerable evidence exists in favor of a second-order transition for\nmassless quarks and a crossover for massive quarks, some recent results with\ntwo flavors of staggered fermions suggest a transition of first order.\n  Since lattice simulations are performed in finite simulation volumes, actual\nphase transitions cannot be observed directly. Thus, finite-size scaling is a\nvery useful tool in the analysis of lattice data. By comparing the scaling\nbehavior of observables to the expected scaling properties, values of critical\nexponents can be confirmed and the order as well as the universality class of a\ntransition can be established. In the comparison to lattice QCD results, the\ncritical exponents and the universal scaling functions have been obtained\nmainly by means of lattice simulations of O(N) spin models, and results are\nusually restricted to the critical temperature or the point at which the\nsusceptibilities peak.\n  We propose to use a non-perturbative Renormalization Group method for this\npurpose. We have calculated the critical finite-size scaling behavior and the\nuniversal scaling functions for the three-dimensional O(4)-model for a wide\nrange of temperatures and values of the symmetry breaking parameter. Our\nresults are suitable for a comparison to lattice QCD results for the chiral\nsusceptibility and the order parameter and can be used to check the consistency\nof the finite-size scaling behavior with that of the O(N) universality class.",
        "positive": "Direct simulations of small multi-fermion systems: I explore computer simulations of the dynamics of small multi-fermion lattice\nsystems. The method is more general, but I concentrate on Hubbard type models\nwhere the fermions hop between a small number of connected sites. I use the\nnatural mapping of fermion occupation numbers onto computer bits. Signs from\nfermion interchange are reduced to bit counting. The technique inherently\nrequires computer resources growing exponentially with the system volume; so,\nit restricted to modestly small systems. Large volume results would require\ncombining these techniques with further approximations, perhaps in a recursive\nrenormalization group manner."
    },
    {
        "anchor": "Domain Wall Fermions and MC Simulations of Vector Theories: It is known that domain wall fermions may be used in MC simulations of vector\ntheories. The practicality and usefulness of such an implementation is\ninvestigated in the context of the vector Schwinger model, on a 2+1 dimensional\nlattice. Preliminary results of a Hybrid Monte Carlo simulation are presented.",
        "positive": "Hybrid Monte-Carlo simulation of interacting tight-binding model of\n  graphene: In this work, results are presented of Hybrid-Monte-Carlo simulations of the\ntight-binding Hamiltonian of graphene, coupled to an instantaneous long-range\ntwo-body potential which is modeled by a Hubbard-Stratonovich auxiliary field.\nWe present an investigation of the spontaneous breaking of the sublattice\nsymmetry, which corresponds to a phase transition from a conducting to an\ninsulating phase and which occurs when the effective fine-structure constant\n$\\alpha$ of the system crosses above a certain threshold $\\alpha_C$.\nQualitative comparisons to earlier works on the subject (which used larger\nsystem sizes and higher statistics) are made and it is established that\n$\\alpha_C$ is of a plausible magnitude in our simulations. Also, we discuss\ndifferences between simulations using compact and non-compact variants of the\nHubbard field and present a quantitative comparison of distinct discretization\nschemes of the Euclidean time-like dimension in the Fermion operator."
    },
    {
        "anchor": "Transverse momentum distributions of quarks from the lattice using\n  extended gauge links: We present preliminary numerical studies in Lattice QCD related to the\nintrinsic transverse momentum distribution of partons in the nucleon. We employ\nnon-local operators, consisting of spatially separated quark creation and\nannihilation operators connected by a straight Wilson line. A clear signal is\nalready obtained from a small number of configurations at a pion mass of about\n600 MeV. As an example, we demonstrate that we can obtain the first x-moment of\nthe transverse momentum dependent parton distribution function f_1^{n=1}(k_T)\nfrom our data. Our results, which are not renormalized, show a Gaussian-like\ndistribution. The root mean squared transverse momentum is about 560 MeV for a\nGaussian fit, close to phenomenological values.",
        "positive": "New mixed inhomogeneous phase in vortical gluon plasma: first-principle\n  results from rotating SU(3) lattice gauge theory: Using first-principle numerical simulations, we find a new spatially\ninhomogeneous phase in rigidly rotating $N_c = 3$ gluon plasma. This mixed\nphase simultaneously possesses both confining and deconfining phases in thermal\nequilibrium. Unexpectedly, the local critical temperature of the phase\ntransition at the rotation axis does not depend on the angular frequency within\na few percent accuracy. Even more surprisingly, an analytic continuation of our\nresults to the domain of real angular frequencies indicates a profound breaking\nof the Tolman-Ehrenfest law in the vicinity of the phase transition, with the\nconfining (deconfining) phase appearing far (near) the rotation axis."
    },
    {
        "anchor": "On the relation between the width of the flux tube and $T_c^{-1}$ in\n  lattice gauge theories: Within the framework of a quantum flux tube model for the interquark\npotential it is possible to predict that in (2+1) dimensions the space-like\nstring tension must increase with the temperature in the deconfined phase and\nthat the thickness of the flux tube must coincide with the inverse of the\ndeconfinement temperature. Both these predictions are in good agreement with\nsome recent numerical simulations of SU(2) and $Z_2$ gauge models.",
        "positive": "Scattering lengths for two pseudoscalar meson systems: Scattering lengths for two pseudoscalar meson systems, $\\pi\\pi(I=2)$,\n$KK(I=1)$ and $\\pi K(I=3/2,\\ 1/2)$, are calculated from lattice QCD by using\nthe finite size formula. We perform the calculation with $N_f=2+1$ gauge\nconfigurations generated on $32^3 \\times 64$ lattice using the Iwasaki gauge\naction and non-perturbatively ${\\cal O}(a)$-improved Wilson action at $a^{-1} =\n2.19$ GeV. The quark masses correspond to $m_\\pi = 0.17 - 0.71$ GeV. For $\\pi\nK(I=1/2)$ system, we use the variational method with the two operators,\n$\\bar{s}u$ and $\\pi K$, to separate the contamination from the higher states.\nIn order to obtain the scattering length at the physical quark mass, we fit our\nresults at the several quark masses with the formula of the ${\\cal O}(p^4)$\nchiral perturbation theory (ChPT) and that including the effects of the\ndiscretization error from the Wilson fermion, Wilson chiral perturbation theory\n(WChPT). We found that the mass dependence of our results near $m_\\pi=0.17$ GeV\nare described well by WChPT but not by ChPT. The scattering lengths at the\nphysical point are given as $a_0^{(2)} m_\\pi =-0.04243(22)(43)$, $a_0^{(1)} m_K\n=-0.312(17)(31)$, $a_0^{(3/2)}\\mu_{\\pi K}=-0.0477(27)(20)$ and\n$a_0^{(1/2)}\\mu_{\\pi K}=0.150(16)(37)$. Possible systematic errors are also\ndiscussed."
    },
    {
        "anchor": "Wilson, fixed point and Neuberger's lattice Dirac operator for the\n  Schwinger model: We perform a comparison between different lattice regularizations of the\nDirac operator for massless fermions in the framework of the single and two\nflavor Schwinger model. We consider a) the Wilson-Dirac operator at the\ncritical value of the hopping parameter; b) Neuberger's overlap operator; c)\nthe fixed point operator. We test chiral properties of the spectrum, dispersion\nrelations and rotational invariance of the mesonic bound state propagators.",
        "positive": "Fast Estimator of jacobians in Monte Carlo Integration on Lefschetz\n  Thimbles: A solution to the sign problem is the so-called \"Lefschetz thimble approach\"\nwhere the domain of integration for field variables in the path integral is\ndeformed from the real axis to a sub-manifold in the complex space. For\nproperly chosen sub-manifolds (\"thimbles\") the sign problem disappears or is\ndrastically alleviated. The parametrization of the thimble by real coordinates\nrequire the calculation of a jacobian with a computational cost of order\nO(V^3), where V is proportional to the spacetime volume. In this note we\npropose two estimators for this jacobian with a computational cost of order\nO(V). We discuss analytically the regimes where we expect the estimator to work\nand show numerical examples in two different models."
    },
    {
        "anchor": "Lattice diffeomorphism invariance: We propose a lattice counterpart of diffeomorphism symmetry in the continuum.\nA functional integral for quantum gravity is regularized on a discrete set of\nspace-time points, with fermionic or bosonic lattice fields. When the\nspace-time points are positioned as discrete points of a continuous manifold,\nthe lattice action can be reformulated in terms of average fields within local\ncells and lattice derivatives. Lattice diffeomorphism invariance is realized if\nthe action is independent of the positioning of the space-time points. Regular\nas well as rather irregular lattices are then described by the same action.\nLattice diffeomorphism invariance implies that the continuum limit and the\nquantum effective action are invariant under general coordinate transformations\n- the basic ingredient for general relativity. In our approach the lattice\ndiffeomorphism invariant actions are formulated without introducing a metric or\nother geometrical objects as fundamental degrees of freedom. The metric rather\narises as the expectation value of a suitable collective field. As examples, we\npresent lattice diffeomorphism invariant actions for a bosonic non-linear\nsigma-model and lattice spinor gravity.",
        "positive": "The Topological Susceptibility of the Lattice CP(n-1) Model on the Torus\n  and the Sphere: The topological vacuum structure of the two-dimensional $~CP^{n-1}~$ model\nfor $~n = 3,5,7~$ is studied on the lattice. In particular we investigate the\nsmall-volume limit on the torus as well as on the sphere and compare with\ncontinuum results. For $~n \\ge 5~$ , where lattice artifacts should be\nsuppressed, the topological susceptibility shows unexpectedly strong deviations\nfrom asymptotic scaling. On the other hand there is an indication for a\nconvergence to values obtained analytically within the limit $~n \\rightarrow\n\\infty~$ ."
    },
    {
        "anchor": "Colour fields of the static hybrid gluon-quark-antiquark system: The colour fields, created by a static gluon-quark-antiquark system, are\ncomputed in quenched SU(3) lattice QCD, in a $24^3\\times 48$ lattice at\n$\\beta=6.2$ and $a=0.07261(85)\\,fm$. We study two geometries, one with a U\nshape and another with an L shape. The particular cases of the two gluon\nglueball and quark-antiquark are also studied, and the Casimir scaling is\ninvestigated in a microscopic perspective. This also contributes to understand\nconfinement with flux tubes and to discriminate between the models of\nfundamental versus adjoint confining strings, analogous to type-II and type-I\nsuperconductivity.",
        "positive": "Individual complex Dirac eigenvalue distributions from random matrix\n  theory and comparison to quenched lattice QCD with a quark chemical potential: We analyze how individual eigenvalues of the QCD Dirac operator at nonzero\nquark chemical potential are distributed in the complex plane. Exact and\napproximate analytical results for both quenched and unquenched distributions\nare derived from non-Hermitian random matrix theory. When comparing these to\nquenched lattice QCD spectra close to the origin, excellent agreement is found\nfor zero and nonzero topology at several values of the quark chemical\npotential. Our analytical results are also applicable to other physical systems\nin the same symmetry class."
    },
    {
        "anchor": "A Comperative Study of Gauge Fixing Procedures on the Connection\n  Machines CM2 and CM5: Gauge fixing is a frequent task encountered in practical lattice gauge theory\ncalculations. We review the performance characteristics of some standard\ngauging procedures for non-abelian gauge theories, implemented on the parallel\nmachines CM2 and CM5.",
        "positive": "The Yang-Mills gradient flow and renormalization: In this proceedings contribution we will review the main ideas behind the\nmany recent works that apply the gradient flow to the determination of the\nrenormalized coupling and the renormalization of composite operators. We will\npay special attention to the continuum extrapolation of flow quantities."
    },
    {
        "anchor": "Chiral Anomaly for a New Class of Lattice Dirac Operators: A new class of lattice Dirac operators which satisfy the index theorem have\nbeen recently proposed on the basis of the algebraic relation\n$\\gamma_{5}(\\gamma_{5}D) + (\\gamma_{5}D)\\gamma_{5} =\n2a^{2k+1}(\\gamma_{5}D)^{2k+2}$. Here $k$ stands for a non-negative integer and\n$k=0$ corresponds to the ordinary Ginsparg-Wilson relation. We analyze the\nchiral anomaly and index theorem for all these Dirac operators in an explicit\nelementary manner. We show that the coefficient of anomaly is independent of a\nsmall variation in the parameters $r$ and $m_{0}$, which characterize these\nDirac operators, and the correct chiral anomaly is obtained in the (naive)\ncontinuum limit $a\\to 0$.",
        "positive": "Testing the heating method with perturbation theory: The renormalization constants present in the lattice evaluation of the\ntopological susceptibility can be non-perturbatively calculated by using the\nso-called heating method. We test this method for the $O(3)$ non-linear\n$\\sigma$-model in two dimensions. We work in a regime where perturbative\ncalculations are exact and useful to check the values obtained from the heating\nmethod. The result of the test is positive and it clarifies some features\nconcerning the method. Our procedure also allows a rather accurate\ndetermination of the first perturbative coefficients."
    },
    {
        "anchor": "Charge Screening, Large-N, and the Abelian Projection Model of\n  Confinement: We point out that the abelian projection theory of quark confinement is in\nconflict with certain large-N predictions. According to both large-N and\nlattice strong-coupling arguments, the perimeter law behavior of adjoint Wilson\nloops at large scales is due to charge-screening, and is suppressed relative to\nthe area term by a factor of $1/N^2$. In the abelian projection theory,\nhowever, the perimeter law is due to the fact that $N-1$ out of $N^2-1$ adjoint\nquark degrees of freedom are (abelian) neutral and unconfined; the suppression\nfactor relative to the area law is thus only $1/N$. We study numerically the\nbehavior of Wilson loops and Polyakov lines with insertions of (abelian) charge\nprojection operators, in maximal abelian gauge. It appears from our data that\nthe forces between abelian charged, and abelian neutral adjoint quarks are not\nsignificantly different. We also show via the lattice strong-coupling expansion\nthat, at least at strong couplings, QCD flux tubes attract one another, whereas\nvortices in type II superconductors repel.",
        "positive": "Perturbative renormalization factors in domain-wall QCD with improved\n  gauge actions: We evaluate renormalization factors of the domain-wall fermion system with\nvarious improved gauge actions at one loop level. The renormalization factors\nare calculated for quark wave function, quark mass, bilinear quark operators,\nthree- and four-quark operators in modified minimal subtraction (MS-bar) scheme\nwith the dimensional reduction(DRED) as well as the naive dimensional\nregularization(NDR). We also present detailed results in the mean field\nimproved perturbation theory."
    },
    {
        "anchor": "Semileptonic $B \\to D^{(\\ast)} \\ell\u03bd$ Decay Form Factors using the\n  Oktay-Kronfeld Action: We report recent progress in calculating semileptonic form factors for the\n$\\bar{B} \\to D^\\ast \\ell \\bar{\\nu}$ and $\\bar{B} \\to D \\ell \\bar{\\nu}$ decays\nusing the Oktay-Kronfeld (OK) action for bottom and charm quarks. We use the\nsecond order in heavy quark effective power counting $\\mathcal{O}(\\lambda^2)$\nimproved currents in this work. The HISQ action is used for the light spectator\nquarks. We analyzed four $2+1+1$-flavor MILC HISQ ensembles with $a\\approx\n0.09\\,\\mathrm{fm}$, $0.12\\,\\mathrm{fm}$ and $M_\\pi \\approx 220\\,\\mathrm{MeV}$,\n$310\\,\\mathrm{MeV}$: $a09m220$, $a09m310$, $a12m220$, $a12m310$. Preliminary\nresults for $B\\to D^\\ast\\ell\\nu$ decays form factor $h_{A_1}(w)$ at zero recoil\n($w=1$) are reported. Preliminary results for $B \\to D\\,\\ell\\nu$ decays form\nfactors $h_\\pm(w)$ over a kinematic range $1<w<1.3$ are reported as well.",
        "positive": "Perturbative renormalization parameters for heavy quarks: We study the heavy quark mass dependence of the perturbative renormalization\nfactors for the heavy-light currents involving Wilson, Clover, and NRQCD heavy\nquarks. We find that the one-loop Z-factor for the axial-vector current depends\nsignificantly on the heavy quark mass commonly for all actions we study, while\nthat for the vector current has smaller dependence."
    },
    {
        "anchor": "Dual Lattice Blockspin Transformation and Monopole condensation in QCD: Recent studies of confinement based on the idea of abelian monopole\ncondensation are reviewed briefly. Emphasis is placed on the approach to get\nthe effective monoole action using the blockspin transformation on the dual\nlattice. The trajectory obtained looks to be the renormalized one in $SU(2)$\nQCD. A disorder parameter of confinement is constructed. Monopole condensation\noccurs also in $SU(3)$ QCD.",
        "positive": "2019 Update on $\\varepsilon_K$ with lattice QCD inputs: We present updated results for $\\varepsilon_K$ determined directly from the\nstandard model (SM) with lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $f_K$, and $m_c$. We find that\nthe standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs\ndescribes only 65\\% of the experimental value of $|\\varepsilon_K|$ and does not\nexplain its remaining 35\\%, which leads to a strong tension in\n$|\\varepsilon_K|$ at the $4.6\\sigma \\sim 4.2\\sigma$ level between the SM theory\nand experiment. We also find that this tension disappears when we use the\ninclusive value of $|V_{cb}|$ obtained using the heavy quark expansion based on\nQCD sum rules."
    },
    {
        "anchor": "Recent results from Lattice QCD: Recent Lattice QCD results are reviewed with an emphasis on spectroscopic\nresults concerning the charm quark. It is demonstrated that, with accurate\ncomputations from lattice QCD in recent years that can be compared with the\nexisting or upcoming experiments, stringent test of the Standard Model can be\nperformed which will greatly sharpen our knowledge on the strong interaction.",
        "positive": "Self-Duality and Statistical Systems without Internal Energy Scaling\n  Terms at Criticality: It is argued that self-duality of one system leads to the zero finite-size\nscaling amplitude of the critical internal energy for all system belonging to\nthe same universality class. For such models, we may expect that condition of\nequality (up to correction-to-scaling terms) of the internal energies for\nsystems with different sizes will yield more accurate estimates for the\ncritical temperature than the scaling equation for the inverse correlation\nlengths which is used in the standard phenomenological renormalization-group\napproach. Analytical and numerical evidences confirming the above conjecture\nare given for examples of two-dimensional next-nearest-neighbour and spin-1\nIsing lattices."
    },
    {
        "anchor": "Multi-level integration for meson propagators: The computation of many correlation functions in lattice QCD is severely\nhindered by a signal-to-noise problem. Recent developments in the factorization\nof both the fermion propagator and determinant pave the way for the\nimplementation of multi-level Monte Carlo integration techniques for lattice\nQCD. In these proceedings we introduce new strategies for the estimation of the\nfactorized contribution to the connected and disconnected diagrams for meson\ntwo-point functions. An estimator for the factorized connected diagram is\nconstructed sequentially for a two-level integration scheme. For the\ndisconnected diagram, we introduce an improved estimator by performing a\nfrequency-splitting of traces, applicable with or without multi-level\nintegration. Preliminary results in the quenched theory with a two-level\nintegration scheme are presented.",
        "positive": "Embedded monopoles in quark eigenmodes in SU(2) Yang-Mills Theory: We study the embedded QCD monopoles (``quark monopoles'') using low-lying\neigenmodes of the overlap Dirac operator in zero- and finite-temperature SU(2)\nYang-Mills theory on the lattice. These monopoles correspond to the\ngauge-invariant hedgehogs in the quark-antiquark condensates. The monopoles\nwere suggested to be agents of the chiral symmetry restoration since their\ncores should suppress the chiral condensate. We study numerically the scalar,\naxial and chirally invariant definitions of the embedded monopoles and show\nthat the monopole densities are in fact globally anti-correlated with the\ndensity of the Dirac eigenmodes. We observe, that the embedded monopoles\ncorresponding to low-lying Dirac eigenvalues are dense in the chirally\ninvariant (high temperature) phase and dilute in the chirally broken (low\ntemperature) phase. We find that the scaling of the scalar and axial monopole\ndensities towards the continuum limit is similar to the scaling of the\nstring-like objects while the chirally invariant monopoles scale as membranes.\nThe excess of gluon energy at monopole positions reveals that the embedded QCD\nmonopole possesses a gluonic core, which is, however, empty at the very center\nof the monopole."
    },
    {
        "anchor": "Generalized Gradient Flow Equation and Its Applications: We propose a generalization of the gradient flow equation for quantum field\ntheories with nonlinearly realized symmetry. Applying the equation to\n$\\mathcal{N}=1$ $SU(N)$ super Yang-Mills theory in four dimensions, we\nconstruct a supersymmetric extension of the gradient flow equation. Choosing an\nappropriate modification term to damp the gauge degree of freedom, we obtain a\ngradient flow equation which is closed within the Wess-Zumino gauge. We also\napply the equation to the $O(N)$ nonlinear sigma model in two dimensions at\nlarge $N$, and show that the two point function in terms of the flowed field is\nnon-perturbatively finite.",
        "positive": "Continuum extrapolated high order baryon fluctuations: Fluctuations play a key role in the study of QCD phases. Lattice QCD is a\nvaluable tool to calculate them, but going to high orders is challenging. Up to\nthe fourth order, continuum results are available since 2015. We present the\nfirst continuum results for sixth order baryon fluctuations for temperatures\nbetween $T=130 - 200$ MeV, and eighth order at $T=145$ MeV in a fixed volume.\nWe show that for $T \\leq 145$ MeV, relevant for criticality search, finite\nvolume effects are under control. Our results are in sharp contrast with well\nknown results in the literature obtained at finite lattice spacing."
    },
    {
        "anchor": "Can we do better than Hybrid Monte Carlo in Lattice QCD?: The Hybrid Monte Carlo algorithm for the simulation of QCD with dynamical\nstaggered fermions is compared with Kramers equation algorithm. We find\nsubstantially different autocorrelation times for local and nonlocal\nobservables. The calculations have been performed on the parallel computer CRAY\nT3D.",
        "positive": "Grassmann integrals by machine: I present a numerical algorithm for direct evaluation of multiple Grassmann\nintegrals. The approach is exact and suffers no Fermion sign problems. Memory\nrequirements grow exponentially with the interaction range and the transverse\nsize of the system. Low dimensional systems of order a thousand Grassmann\nvariables can be evaluated on a workstation."
    },
    {
        "anchor": "Individual eigenvalue distributions of crossover chiral random matrices\n  and low-energy constants of SU(2)$\\times$U(1) lattice gauge theory: We compute individual distributions of low-lying eigenvalues of a chiral\nrandom matrix ensemble interpolating symplectic and unitary symmetry classes by\nthe Nystr\\\"om-type method of evaluating the Fredholm Pfaffian and resolvents of\nthe quaternion kernel. The one-parameter family of these distributions are\nshown to fit excellently the Dirac spectra of SU(2) lattice gauge theory with a\nconstant U(1) background or dynamically fluctuating U(1) gauge field, which\nweakly breaks the pseudo-reality of the unperturbed SU(2) Dirac operator.\nObserved linear dependence of the crossover parameter with the strength of U(1)\nperturbations leads to precise determination of the pseudo-scalar decay\nconstant, as well as the chiral condensate in the effective chiral Lagrangian\nof AI class.",
        "positive": "Low Temperature Expansions for Potts Models: On simple cubic lattices, we compute low temperature series expansions for\nthe energy, magnetization and susceptibility of the three-state Potts model in\nD=2 and D=3 to 45 and 39 excited bonds respectively, and the eight-state Potts\nmodel in D=2 to 25 excited bonds. We use a recursive procedure which enumerates\nstates explicitly. We analyze the series using Dlog Pade analysis and\ninhomogeneous differential approximants."
    },
    {
        "anchor": "Complex Langevin dynamics and zeroes of the fermion determinant: QCD at nonzero baryon chemical potential suffers from the sign problem, due\nto the complex quark determinant. Complex Langevin dynamics can provide a\nsolution, provided certain conditions are met. One of these conditions,\nholomorphicity of the Langevin drift, is absent in QCD since zeroes of the\ndeterminant result in a meromorphic drift. We first derive how poles in the\ndrift affect the formal justification of the approach and then explore the\nvarious possibilities in simple models. The lessons from these are subsequently\napplied to both heavy dense QCD and full QCD, and we find that the results\nobtained show a consistent picture. We conclude that with careful monitoring,\nthe method can be justified a posteriori, even in the presence of\nmeromorphicity.",
        "positive": "Fixed-point action for fermions in QCD: We report our progress constructing a fixed-point action for fermions\ninteracting with SU(3) gauge fields."
    },
    {
        "anchor": "Leptonic widths of heavy quarkonia: QCD/NRQCD matching for the\n  electromagnetic current at O(\u03b1_s v^2): We construct the S-wave part of the electromagnetic vector annihilation\ncurrent to $O(\\alpha_s v^2)$, where $v$ is the non-relativistic quark velocity,\nfor heavy quarks whose dynamics are described by the NRQCD action on the\nlattice. The NRQCD vector current for $Q\\bar{Q}$ annihilation is expressed as a\nlinear combination of lattice operators with quantum numbers L=0, $J^P=1^-$,\nand the coefficients are determined by matching to the corresponding continuum\ncurrent in QCD to$O(v^2)$ at one-loop. The annihilation channel gives a complex\namplitude with Coulomb-exchange and infrared singularities, making a careful\nchoice for the contours of integration and infrared subtraction functions in\nthe numerical integration necessary. An automated vertex generation program\nwritten in Python is employed, allowing us to use a realistic NRQCD action and\nan improved gluon lattice action; a change in the definition of either action\nis easily accommodated in this procedure. The final result is applicable to\nsimulations of electromagnetic decays of heavy quarkonia, notably the\n$\\Upsilon$ meson.",
        "positive": "$\u03c0\u03c0$ scattering in partially-quenched twisted-mass chiral\n  perturbation theory: We study pion-pion scattering in partially-quenched twisted-mass lattice QCD\nusing chiral perturbation theory. The specific partially-quenched setup\ncorresponds to that used in numerical lattice QCD calculations of the $I=0$\nscattering length. We study the discretization errors proportional to $a^2$,\nwith $a$ the lattice spacing, and the errors that arise due to the use of\nL\\\"uscher's two-particle quantization condition in a theory that is not\nunitary. We argue that the former can be as large as $\\sim 100\\%$, but explain\nhow they can be systematically subtracted using a calculation of the $I=2$\nscattering amplitude in the same partially-quenched framework. We estimate the\nerror from the violation of unitarity to be $\\sim 25\\%$, and argue that this\nerror will be difficult to reduce in practice."
    },
    {
        "anchor": "Non-Gaussianity of the topological charge distribution in\n  $\\mathrm{SU}(3)$ Yang-Mills theory: In Yang-Mills theory, the cumulants of the na\\\"ive lattice discretization of\nthe topological charge evolved with the Yang-Mills gradient flow coincide, in\nthe continuum limit, with those of the universal definition. We sketch in these\nproceedings the main points of the proof. By implementing the gradient-flow\ndefinition in numerical simulations, we report the results of a precise\ncomputation of the second and the fourth cumulant of the $\\mathrm{SU}(3)$\nYang-Mills theory topological charge distribution, in order to measure the\ndeviation from Gaussianity. A range of high-statistics Monte Carlo simulations\nwith different lattice volumes and spacings is used to extrapolate the results\nto the continuum limit with confidence by keeping finite-volume effects\nnegligible with respect to the statistical errors. Our best result for the\ntopological susceptibility is $t_0^2\\chi=6.67(7)\\times 10^{-4}$, while for the\nratio between the fourth and the second cumulant we obtain $R=0.233(45)$.",
        "positive": "A dynamical study of the chirally rotated Schr\u00f6dinger functional in\n  QCD: The chirally rotated Schr\\\"odinger functional for Wilson-fermions allows for\nfinite-volume, mass-independent renormalization schemes compatible with\nautomatic O($a$) improvement. So far, in QCD, the set-up has only been studied\nin the quenched approximation. Here we present first results for $N_{\\rm f} =\n2$ dynamical quark-flavours for several renormalization factors of\nquark-bilinears. We discuss how these renormalization factors can be easily\nobtained from simple ratios of two-point functions, and show how automatic\nO($a$) improvement is at work. As a by-product of this investigation the\nrenormalization of the non-singlet axial current, $Z_A$, is determined very\nprecisely."
    },
    {
        "anchor": "I=2 Pion Scattering Length from a Coarse Anisotropic Lattice Calculation: Using the tadpole improved clover Wilson quark action on coarse anisotropic\nlattices, the $\\pi\\pi$ scattering length in the I=2 channel is calculated\nwithin quenched approximation. We show that such a calculation is feasible\nusing small lattices on small computers provided that the finite volume and\nfinite lattice spacing errors are under control. Our results are extrapolated\ntowards the chiral, infinite volume and continuum limit. Comparisons of our\nresults with previous lattice results from JLQCD collaboration, the new results\nfrom E865 experiment, and the results from Chiral Perturbation Theory are made.\nGood agreements are found.",
        "positive": "Quantum Field Theories with Tensor Renormalization Group: We report recent progress on the application of the tensor renormalization\ngroup (TRG) to quantum field theories pursued by the Tsukuba group. We explain\nhow to treat the scalar, fermion, and gauge theories with the TRG method\npresenting the results for the phase transitions in the (3+1)-dimensional\n((3+1)$d$) complex $\\phi^4$ theory at finite density, (1+1)$d$ pure U(1)\nlattice gauge theory with a $\\theta$ term, (3+1)$d$ Nambu--Jona-Lasinio model\nat finite density and (1+1)$d$ and (2+1)$d$ Hubbard models at an arbitrary\nchemical potential. It is demonstrated that the TRG method is free from the\nsign problem in practical calculations and applicable to the four-dimensional\nmodels."
    },
    {
        "anchor": "Lattice computation of $B \\to D^*,\\;D^{**}\\ell \u03bd$ form factors at\n  finite heavy masses: We propose a strategy to compute form factors entering the semileptonic decay\nchannel of $B$ mesons into orbitally excited (P wave) $D^{**}$ charmed mesons\non the lattice using, for the first time, realistic charm quarks having a\nfinite mass. We present preliminary results about the extracted transition\namplitudes and form factors at different recoils and at three different $b$\nquark masses.",
        "positive": "Wess-Zumino model with exact supersymmetry on the lattice: A lattice formulation of the four dimensional Wess-Zumino model that uses\nGinsparg-Wilson fermions and keeps exact supersymmetry is presented. The\nsupersymmetry transformation that leaves invariant the action at finite lattice\nspacing is determined by performing an iterative procedure in the coupling\nconstant. The closure of the algebra, generated by this transformation is also\nshowed."
    },
    {
        "anchor": "$\u03b1_S$ from Lattice QCD: progresses and perspectives for a realistic\n  full-QCD determination of the running Strong coupling: Some very recent computations of $\\alpha_{\\bar{\\rm MS}}(M_Z)$ from $N_f=1+1$\nlattice simulations and of the running of the Strong coupling, obtained from\nthe lattice ghost-gluon vertex, over a large momentum window are very briefly\nreviewed.",
        "positive": "Two dimensional SU(N) x SU(N) chiral models on the lattice: Lattice $SU(N)\\times SU(N)$ chiral models are analyzed by strong and weak\ncoupling expansions and by numerical simulations. $12^{th}$ order strong\ncoupling series for the free and internal energy are obtained for all $N\\geq\n6$. Three loop contributions to the internal energy and to the lattice\n$\\beta$-function are evaluated for all $N$ and non-universal corrections to the\nasymptotic $\\Lambda$ parameter are computed in the ``temperature'' and the\n``energy'' scheme. Numerical simulations confirm a faster approach to\nasymptopia of the energy scheme. A phenomenological correlation between the\npeak in the specific heat and the dip of the $\\beta$-function is observed.\nTests of scaling are performed for various physical quantities, finding\nsubstantial scaling at $\\xi \\gtrsim 2$. In particular, at $N=6$ three different\nmass ratios are determined numerically and found in agreement, within\nstatistical errors of about 1\\%, with the theoretical predictions from the\nexact S-matrix theory."
    },
    {
        "anchor": "Finite-Volume Effects for Two-Hadron States in Moving Frames: We determine the finite-volume corrections to the spectrum and matrix\nelements of two-hadron states in a moving frame, i.e. one in which the total\nmomentum of the two-hadrons is non-zero. The analysis is performed entirely\nwithin field theory and the results are accurate up to exponential corrections\nin the volume. Our results for the spectrum are equivalent to those of\nRummukainen and Gottlieb which had been obtained using a relativistic quantum\nmechanical approach. A technical step in our analysis is a simple derivation of\nthe summation formulae relating the loop summations over the momenta of the two\nhadrons in finite volume to the corresponding integrals in infinite volume.",
        "positive": "Radially Excited States of 1P Charmonia and X(3872): The excited states of charmonia are numerically investigated in quenched\nlattice QCD with improved gauge and Wilson fermion actions formulated on\nanisotropic lattices. Through a constrained curve fitting algorithm, the masses\nof the first excited states in $0^{++}$, $1^{++}$, and $1^{+-}$ channels are\ndetermined to be 3.825(88), 3.853(57), and 3.858(70) GeV, respectively.\nFurthormore, a node structure is also observed in the Bethe-Salpeter amplitude\nof the $1^{++}$ first excited state. These observations indicate that X(3872)\ncould be the first radial excitation of $\\chi_{c1}$."
    },
    {
        "anchor": "Lattice QCD and Nuclear Physics: A short lecture given at the Summer School on \"Modern perspectives in lattice\nQCD\", Les Houches, August 3-28, 2009.",
        "positive": "$B^0-\\bar{B}^0$ mixing in quenched lattice QCD: We present our results of lattice calculations of $B$ parameters, which\nparameterize $\\Delta B$=2 transition amplitudes together with the leptonic\ndecay constant. Calculations are made in the quenched approximation at\n$\\beta$=5.7, 5.9, 6.0 and 6.1, using NRQCD action for heavy quark and the\n$O(a)$-improved Wilson action for light quark. The operators are perturbatively\nrenormalized including the correction of $O(\\alpha_s/(aM)^m)$ ($m\\ge$0). We\nexamine the scaling behavior of $B$ parameters, and discuss the systematic\nuncertainties based on the results with several different truncations of higher\norder terms in 1/M and $\\alpha_s$ expansions. We find\n$B_{B_d}(m_b)=0.84(3)(5)$,\n$B_{B_s}/B_{B_d}=1.020(21)(^{+15}_{-16})(^{+5}_{-0})$ and\n$B_{S_s}(m_b)=0.85(1)(5)(^{+1}_{-0})$ in the quenched approximation. The errors\nrepresent statistical and systematic as well as the uncertainty in the\ndetermination of strange quark mass."
    },
    {
        "anchor": "Domain wall fermions in vector gauge theories: I review domain wall fermions in vector gauge theories. Following a brief\nintroduction, the status of lattice calculations using domain wall fermions is\npresented. I focus on results from QCD, including the light quark masses and\nspectrum, weak matrix elements, the $n_f=2$ finite temperature phase\ntransition, and topology and zero modes and conclude with topics for future\nstudy.",
        "positive": "Lattice QCD analysis of the Polyakov loop in terms of Dirac eigenmodes: Using the Dirac-mode expansion method, which keeps the gauge invariance, we\nanalyze the Polyakov loop in terms of the Dirac modes in SU(3) quenched lattice\nQCD in both confined and deconfined phases. First, to investigate the direct\ncorrespondence between confinement and chiral symmetry breaking, we remove\nlow-lying Dirac-modes from the confined vacuum generated by lattice QCD. In\nthis system without low-lying Dirac modes, while the chiral condensate $\\langle\n\\bar{q} q\\rangle$ is extremely reduced, we find that the Polyakov loop is\nalmost zero and $Z_3$-center symmetry is unbroken, which indicates quark\nconfinement. We also investigate the removal of ultraviolet (UV) Dirac-modes,\nand find that the Polyakov loop is almost zero. Second, we deal with the\ndeconfined phase above $T_c$, and find that the behaviors of the Polyakov loop\nand $Z_3$-symmetry are not changed without low-lying or UV Dirac-modes.\nFinally, we develop a new method to remove low-lying Dirac modes from the\nPolyakov loop for a larger lattice of $12^3 \\times 4$ at finite temperature,\nand find almost the same results. These results suggest that each eigenmode has\nthe information of confinement, i.e., the \"seed\" of confinement is distributed\nin a wider region of the Dirac eigenmodes unlike chiral symmetry breaking, and\nthere is no direct correspondence between confinement and chiral symmetry\nbreaking through Dirac-eigenmodes."
    },
    {
        "anchor": "B-Bbar Mixing and Matching with Fermilab Heavy Quarks: We discuss the matching procedure for heavy-light 4-quark operators using the\nFermilab method for heavy quarks and staggered fermions for light quarks. These\ningredients enable us to construct the continuum-limit operator needed to\ndetermine the oscillation frequency of neutral B mesons. The matching is then\ncarried out at the one-loop level. We also present an updated preliminary\nresult for the SU(3)-breaking ratio \\xi, based on calculations using the MILC\nCollaboration's ensembles of lattice gauge fields.",
        "positive": "Investigating jet quenching on the lattice: Due to the dynamical, real-time, nature of the phenomenon, the study of jet\nquenching via lattice QCD simulations is not straightforward. In this\ncontribution, however, we show how one can extract information about the\nmomentum broadening of a hard parton moving in the quark-gluon plasma, from\nlattice calculations. After discussing the basic idea (originally proposed by\nCaron-Huot), we present a recent study, in which we estimated the jet quenching\nparameter non-perturbatively, from the lattice evaluation of a particular set\nof gauge-invariant operators."
    },
    {
        "anchor": "Color-Flavor Transformation for the Special Unitary Group and\n  Application to Low Energy QCD: The color-flavor transformation for the unitary group (Zirnbauer 1996) is\nextended to the special unitary group. The resulting partition function is\nrepresented as sum over disconnected sectors characterized by a U(1)-charge.\nApplication to low energy QCD on a lattice leads to a theory where the inverse\nnumber of colors appears as expansion parameter. We use a saddle point\napproximation to estimate the partition function both in the pure mesonic\nsector and in the case of a single baryon on a mesonic background.",
        "positive": "Numerical sign problem and the tempered Lefschetz thimble method: The numerical sign problem is a major obstacle to the quantitative\nunderstanding of many important physical systems with first-principles\ncalculations. Typical examples for such systems include finite-density QCD,\nstrongly-correlated electron systems and frustrated spin systems, as well as\nthe real-time dynamics of quantum systems. In this talk, we argue that the\n\"tempered Lefschetz thimble method\" (TLTM) [M. Fukuma and N. Umeda,\narXiv:1703.00861] and its extension, the \"worldvolume tempered Lefschetz\nthimble method\" (WV-TLTM) [M. Fukuma and N. Matsumoto, arXiv:2012.08468], may\nbe a reliable and versatile solution to the sign problem. We demonstrate the\neffectiveness of the algorithm by exemplifying a successful application of\nWV-TLTM to the Stephanov model, which is an important toy model of\nfinite-density QCD. We also discuss the computational scaling of WV-TLTM."
    },
    {
        "anchor": "Computing the viscosity of the QGP on the lattice: I review the recent progress made in calculating shear and bulk viscosity on\nthe lattice, and discuss ways to improve the calculation.",
        "positive": "Degeneracy of vector-channel spatial correlators in high temperature QCD: We study spatial isovector meson correlators in $N_f=2$ QCD with dynamical\ndomain-wall fermions on $32^3\\times 8$ lattices at temperatures up to 380 MeV\nwith various quark masses. We measure the correlators of spin-one isovector\noperators including vector, axial-vector, tensor and axial-tensor. At\ntemperatures above $T_c$ we observe an approximate degeneracy of the\ncorrelators in these channels, which is unexpected because some of them are not\nrelated under $SU(2)_L \\times SU(2)_R$ nor $U(1)_A$ symmetries. The observed\napproximate degeneracy suggests emergent $SU(2)_{CS}$ (chiral-spin) and $SU(4)$\nsymmetries at high $T$."
    },
    {
        "anchor": "Reconfinement, localization and thermal monopoles in $SU(3)$\n  trace-deformed Yang-Mills theory: We study, by means of numerical lattice simulations, the properties of the\nreconfinement phase transition taking place in trace deformed $SU(3)$\nYang-Mills theory defined on $\\mathbb{R}^3\\times S^1$, in which center symmetry\nis recovered even for small compactification radii. We show, by means of a\nfinite size scaling analysis, that the reconfinement phase transition is\nfirst-order, like the usual $SU(3)$ thermal phase transition. We then\ninvestigate two different physical phenomena, which are known to characterize\nthe standard confinement/deconfinement phase transition, namely the\ncondensation of thermal magnetic monopoles and the change in the localization\nproperties of the eigenmodes of the Dirac operator. Regarding the latter, we\nshow that the mobility edge signalling the Anderson-like transition in the\nDirac spectrum vanishes as one enters the reconfined phase, as it happens in\nthe standard confined phase. Thermal monopoles, instead, show a peculiar\nbehavior: their density decreases going through reconfinement, at odds with the\nstandard thermal theory; nonetheless, they condense at reconfinement, like at\nthe usual confinement transition. The coincidence of monopole condensation and\nDirac mode delocalization, even in a framework different from that of the\nstandard confinement transition, suggests the existence of a strict link\nbetween them.",
        "positive": "Adler function and hadronic vacuum polarization from lattice vector\n  correlators: We study a representation of the hadronic vacuum polarization based on the\ntime-momentum representation of the vector correlator. This representation\nsuggests a way to compute the hadronic vacuum polarization and the associated\nAdler function for any value of virtuality, irrespective of the flavor\nstructure of the current. We present results on both of these\nphenomenologically important functions, derived from local-conserved two-point\nlattice vector correlation functions, computed on a subset of light two-flavor\nensembles made available to us through the CLS effort."
    },
    {
        "anchor": "Sensitivity of the Polyakov loop to chiral symmetry restoration: In the heavy, static quark mass regime of QCD, the Polyakov loop is well\nknown to be an order parameter of the deconfinement phase transition; however,\nthe sensitivity of the Polyakov loop to the deconfinement of light, dynamical\nquarks is less clear. On the other hand, from the perspective of an effective\nLagrangian written in the vicinity of the chiral transition, the Polyakov loop\nis an energy-like operator and should hence scale as any energy-like operator\nwould. We show here that the Polyakov loop and heavy-quark free energy are\nsensitive to the chiral transition, i.e. their scaling is consistent with\nenergy-like observables in 3-$d$ $O(N)$ universality classes.",
        "positive": "The Deconfinement Phase Transition in One-Flavour QCD: We present a study of the deconfinement phase transition of one-flavour QCD,\nusing the multiboson algorithm. The mass of the Wilson fermions relevant for\nthis study is moderately large and the non-hermitian multiboson method is a\nsuperior simulation algorithm. Finite size scaling is studied on lattices of\nsize $8^3\\times 4$, $12^3\\times 4$ and $16^3\\times 4$. The behaviours of the\npeak of the Polyakov loop susceptibility, the deconfinement ratio and the\ndistribution of the norm of the Polyakov loop are all characteristic of a\nfirst-order phase transition for heavy quarks. As the quark mass decreases, the\nfirst-order transition gets weaker and turns into a crossover. To investigate\nfinite size scaling on larger spatial lattices we use an effective action in\nthe same universality class as QCD. This effective action is constructed by\nreplacing the fermionic determinant with the Polyakov loop identified as the\nmost relevant Z(3) symmetry breaking term. Higher-order effects are\nincorporated in an effective Z(3)-breaking field, $h$, which couples to the\nPolyakov loop. Finite size scaling determines the value of $h$ where the first\norder transition ends. Our analysis at the end - point, $h_{ep}$, indicates\nthat the effective model and thus QCD is consistent with the universality class\nof the three dimensional Ising model.\n  Matching the field strength at the end point, $h_{ep}$, to the $\\kappa$\nvalues used in the dynamical quark simulations we estimate the end point,\n$\\kappa_{ep}$, of the first-order phase transition. We find $\\kappa_{ep}\\sim\n0.08 $ which corresponds to a quark mass of about 1.4 GeV ."
    },
    {
        "anchor": "Three-quark potentials in an $SU(3)$ effective Polyakov loop model: Three-quark potentials are studied in great details in the three-dimensional\n$SU(3)$ pure gauge theory at finite temperature, for the cases of static\nsources in the fundamental and adjoint representations. For this purpose, the\ncorresponding Polyakov loop model in its simplest version is adopted. The\npotentials in question, as well as the conventional quark--anti-quark\npotentials, are calculated numerically both in the confinement and\ndeconfinement phases. Results are compared to available analytical predictions\nat strong coupling and in the limit of large number of colors $N$. The\nthree-quark potential is tested against the expected $\\Delta$ and $Y$ laws and\nthe $3q$ string tension entering these laws is compared to the conventional\n$q\\bar{q}$ string tension. As a byproduct of this investigation, essential\nfeatures of the critical behaviour across the deconfinement transition are\nelucidated.",
        "positive": "Quantum Gate Sets for Lattice QCD in the strong coupling limit: $N_f=1$: We derive the primitive quantum gate sets to simulate lattice quantum\nchromodynamics (LQCD) in the strong-coupling limit with one flavor of massless\nstaggered quarks. This theory is of interest for studies at non-zero density as\nthe sign problem can be overcome using Monte Carlo methods. In this work, we\nuse it as a testing ground for quantum simulations. The key point is that no\ntruncation of the bosonic Hilbert space is necessary as the theory is\nformulated in terms of color-singlet degrees of freedom (``baryons'' and\n``mesons''). The baryons become static in the limit of continuous time and\ndecouple, whereas the dynamics of the mesonic theory involves two qubits per\nlattice site. Lending dynamics also to the ``baryons'' simply requires to use\nthe derived gate set in its controlled version."
    },
    {
        "anchor": "Extraction of $|V_{cd}|$ and $|V_{cs}|$ from experimental decay rates\n  using lattice QCD $D \\to \u03c0(K) \\ell \u03bd$ form factors: We present a determination of the Cabibbo-Kobayashi-Maskawa matrix elements\n$|V_{cd}|$ and $|V_{cs}|$ obtained by combining the momentum dependence of the\nsemileptonic vector form factors $f_+^{D \\to \\pi}(q^2)$ and $f_+^{D \\to\nK}(q^2)$, recently determined from lattice QCD simulations, with the\ndifferential rates measured for the semileptonic $D \\to \\pi \\ell \\nu$ and $D\n\\to K \\ell \\nu$ decays. Our analysis is based on the results for the\nsemileptonic form factors produced by the European Twisted Mass Collaboration\nwith $N_f = 2 + 1 + 1$ flavors of dynamical quarks in the whole range of values\nof the squared 4-momentum transfer accessible in the experiments. The\nstatistical and systematic correlations between the lattice data as well as\nthose present in the experimental data are properly taken into account. With\nrespect to the standard procedure based on the use of only the vector form\nfactor at zero 4-momentum transfer, we obtain more precise and consistent\nresults: $|V_{cd} |= 0.2341 ~ (74)$ and $|V_{cs} |= 0.970 ~ (33)$. The\nsecond-row CKM unitarity is fulfilled within the current uncertainties:\n$|V_{cd}|^2 + |V_{cs}|^2 + |V_{cb}|^2 = 0.996 ~ (64)$. Moreover, using for the\nfirst time hadronic inputs determined from first principles, we have calculated\nthe ratio of the semileptonic $D \\to \\pi(K)$ decay rates into muons and\nelectrons, which represent a test of lepton universality within the SM,\nobtaining in the isospin-symmetric limit of QCD: ${\\cal{R}}_{LU}^{D\\pi} =\n0.985~(2)$ and ${\\cal{R}}_{LU}^{DK} = 0.975~(1)$.",
        "positive": "Supercurrent Flow in NJL_{2+1} at High Baryon Density: We present results of numerical simulations of the 2+1d Nambu -- Jona-Lasinio\nmodel with non-zero baryon chemical potential mu and spatially-varying complex\ndiquark source strength j. By choosing arg(j) to vary smoothly through 2 pi\nacross the spatial extent of the lattice, a baryon number current is induced\nwhich in the high density phase remains non-vanishing as |j|->0; we are hence\nable to extract a quantity characteristic of a superfluid known as the helicity\nmodulus. We also study supercurrent flow at non-zero temperature and estimate\nthe critical temperature at which the normal phase is restored, which is\nconsistent with the conventional picture for thin-film superfluids in which the\ntransition is viewed in terms of vortex -- anti-vortex unbinding."
    },
    {
        "anchor": "Perfect Lattice Perturbation Theory: A Study of the Anharmonic\n  Oscillator: As an application of perfect lattice perturbation theory, we construct an\nO(\\lambda) perfect lattice action for the anharmonic oscillator analytically in\nmomentum space. In coordinate space we obtain a set of 2-spin and 4-spin\ncouplings \\propto \\lambda, which we evaluate for various masses. These\ncouplings never involve variables separated by more than two lattice spacings.\nThe O(\\lambda) perfect action is simulated and compared to the standard action.\nWe discuss the improvement for the first two energy gaps \\Delta E_1, \\Delta E_2\nand for the scaling quantity \\Delta E_2 / \\Delta E1 in different regimes of the\ninteraction parameter, and of the correlation length.",
        "positive": "Finite-Size Effects in the Interface of 3D Ising Model: The interface between domains of opposite magnetization in the 3D Ising model\nnear the critical temperature displays universal finite-size effects which can\nbe described in terms of a gaussian model of capillary waves. It turns out that\nthese finite-size corrections depend rather strongly on the shape of the\nlattice. This prediction, which has no adjustable parameters, is tested and\naccurately verified for various lattice shapes by means of numerical\nsimulations with a cluster algorithm. This supports also a long-standing\nconjecture on the finite-size effects in Wilson loops of Lattice Gauge\nTheories."
    },
    {
        "anchor": "Scale Determination Using the Static Potential with Two Dynamical Quark\n  Flavors: We study the static potential using gauge configurations that include the\neffects of two flavors of dynamical Kogut-Susskind quarks. The configurations,\ngenerated by the MILC collaboration, and used to study the spectrum and\nheavy-light decay constants, cover a range $5.3 \\le 6/g^2 \\le 5.6$. There are\nat least four quark masses for each coupling studied. Determination of $r_0$\nfrom the potential can be used to set a scale. This alternative scale is useful\nto study systematic errors on the spectrum and decay constants.",
        "positive": "Confinement, Chiral Symmetry Breaking and Continuum Limits in Quantum\n  Link Models: Using the example of compact U(1) lattice gauge theory we argue that quantum\nlink models can be used to reproduce the physics of conventional Hamiltonian\nlattice gauge theories. In addition to the usual gauge coupling $g$, these\nmodels have a new parameter $j$ which naturally cuts-off large electric flux\nquanta on each link while preserving exact U(1) gauge invariance. The\n$j\\to\\infty$ limit recovers the conventional Hamiltonian. At strong couplings,\nthe theory shows confinement and chiral symmetry breaking for all non-trivial\nvalues of $j$. The phase diagram of the 3+1 dimensional theory suggests that a\ncoulomb phase is present at large but finite $j$. Setting $g=0$, a new approach\nto the physics of compact U(1) gauge theory on the lattice emerges. In this\ncase the parameter $j$ takes over the role of the gauge coupling, and $j\\to\n\\infty$ describes free photons."
    },
    {
        "anchor": "Perturbative matching of heavy-light currents at one-loop: We present results of a perturbative matching calculation performed at\none-loop for heavy-light currents. We use the Fermilab action for the heavy\nquarks, the Asqtad action for the light quarks, and an improved gluon action.\nWe also present results for heavy-heavy currents with Fermilab heavy quarks and\nimproved glue.",
        "positive": "Massless Fermions on the Lattice: We consider a nonlocal lattice action for fermions fermion doubling in\nlattice theories. It is shown, that it is possible to avoid the fermionic\ndoubling in the case of free fermions, but this approach does not reproduce\nresults for the effective action for gauge fields in the continuum theory,\nbecause the high frequency fermion modes have a strong dependence on the gauge\nfield."
    },
    {
        "anchor": "Evidence for Complex Subleading Exponents from the High-Temperature\n  Expansion of the Hierarchical Ising Model: Using a renormalization group method, we calculate 800 high-temperature\ncoefficients of the magnetic susceptibility of the hierarchical Ising model.\nThe conventional quantities obtained from differences of ratios of coefficients\nshow unexpected smooth oscillations with a period growing logarithmically and\ncan be fitted assuming corrections to the scaling laws with complex exponents.",
        "positive": "The Exotic Baryon Theta^+(1540) on the Lattice: We report on a study of the pentaquark Theta^+(1540), using a variety of\ndifferent interpolating fields. We use Chirally Improved fermions in\ncombination with Jacobi smeared quark sources to improve the signal and get\nreliable results even for small quark masses. The results of our quenched\ncalculations, which have been done on a 12^3x24 lattice with a lattice spacing\nof a=0.148 fm, do not provide any evidence for the existence of a Theta^+ with\npositive parity. We do observe, however, a signal compatible with nucleon-kaon\nscattering state. For the negative parity the results are inconclusive, due to\nthe potential mixture with nucleon-kaon and N*-kaon scattering states."
    },
    {
        "anchor": "Coupled-channel scattering in 1+1 dimensional lattice model: Based on the Lippmann-Schwinger equation approach, a generalized L\\\"uscher's\nformula in 1+1 dimensions for two particles scattering in both the elastic and\ncoupled-channel cases in moving frames is derived. A 2D coupled-channel\nscattering lattice model is presented, the model represents a\ntwo-coupled-channel resonant scattering scalars system. The Monte Carlo\nsimulation is performed on finite lattices and in various moving frames.\n  The 2D generalized L\\\"uscher's formula is used to extract the scattering\namplitudes for the coupled-channel system from the discrete finite-volume\nspectrum.",
        "positive": "The $\u03b8$-dependence of the $\\mathrm{SU}(N)$ critical temperature at\n  large $N$: We investigate, by means of numerical lattice simulations, the\n$\\theta$-dependence of the critical deconfinement temperature of\n$\\mathrm{SU}(N)$ gauge theories at large $N$: $T_c(\\theta) =\nT_c(0)[1-R\\theta^2+O(\\theta^4)]$, with $R\\sim O(1/N^2)$. We follow two\ndifferent strategies to determine $R$, one based on the calculation of the\nlatent heat of the transition and on the jump of the topological susceptibility\nat the $\\theta=0$ critical point, the other relying on a direct probe of\n$T_c(\\theta)$ by means of imaginary-$\\theta$ Monte Carlo simulations. Our\nresults show that $R$ follows the expected large-$N$ scaling."
    },
    {
        "anchor": "Localization with overlap fermions: We study the finite temperature localization transition in the spectrum of\nthe overlap Dirac operator. Simulating the quenched approximation of QCD, we\ncalculate the mobility edge, separating localized and delocalized modes in the\nspectrum. We do this at several temperatures just above the deconfining\ntransition and by extrapolation we determine the temperature where the mobility\nedge vanishes and localized modes completely disappear from the spectrum. We\nfind that this temperature, where even the lowest Dirac eigenmodes become\ndelocalized, coincides with the critical temperature of the deconfining\ntransition. This result, together with our previously obtained similar findings\nfor staggered fermions shows that quark localization at the deconfining\ntemperature is independent of the fermion discretization, suggesting that\ndeconfinement and localization of the lowest Dirac eigenmodes are closely\nrelated phenomena.",
        "positive": "The eta' meson from lattice QCD: We study the flavour singlet pseudoscalar mesons from first principles using\nlattice QCD. With N_f=2 flavours of light quark, this is the so-called eta_2\nmeson and we discuss the phenomenological status of this. Using maximally\ntwisted-mass lattice QCD, we extract the mass of the eta_2 meson at two values\nof the lattice spacing for lighter quarks than previously discussed in the\nliterature. We are able to estimate the mass value in the limit of light quarks\nwith their physical masses."
    },
    {
        "anchor": "Diquark condensation in dense adjoint matter: We study SU(2) lattice gauge theory at non-zero chemical potential with one\nstaggered quark flavor in the adjoint representation. In this model the fermion\ndeterminant, although real, can be both positive and negative. We have\nperformed numerical simulations using both hybrid Monte Carlo and two-step\nmultibosonic algorithms, the latter being capable of exploring sectors with\neither determinant sign. We find that the positive determinant sector behaves\nlike a two-flavor theory, with the chiral condensate rotating into a two-flavor\ndiquark condensate for mu>m_pi/2, implying a superfluid ground state. Good\nagreement is found with analytical predictions made using chiral perturbation\ntheory. In the `full' model there is no sign of either onset of baryon density\nor diquark condensation for the range of chemical potentials we have\nconsidered. The impact of the sign problem has prevented us from exploring the\ntrue onset transition and the mode of diquark condensation, if any, for this\nmodel.",
        "positive": "A test of first order scaling in Nf =2 QCD: a progress report: We present the status of our analysis on the order of the finite temperature\ntransition in QCD with two flavors of degenerate fermions. Our new simulations\non large lattices support the hypothesis of the first order nature of the\ntransition, showing a preliminary two state signal. We will discuss the\nimplications and the next steps in our analysis."
    },
    {
        "anchor": "Heavy Baryons from Lattice NRQCD: The mass spectrum of heavy quark baryons has been computed on anisotropic\nlattices using quenched lattice nonrelativistic QCD. The mass splittings\nbetween spin-1/2 and spin-3/2 baryons are also calculated. Results are compared\nto those obtained by using a Dirac-Wilson action of the D234 type. Color\nhyperfine effects in heavy baryons are also discussed.",
        "positive": "Landau gauge ghost propagator and running coupling in SU(2) lattice\n  gauge theory: We study finite (physical) volume and scaling violation effects of the Landau\ngauge ghost propagator as well as of the running coupling $\\alpha_s(p)$ in the\n$SU(2)$ lattice gauge theory. We consider lattices with physical linear sizes\nbetween $aL \\simeq 3$ fm and $7$ fm and values of lattice spacing between\n$a=0.2$ fm and $0.07$ fm. To fix the gauge we apply an efficient gauge fixing\nmethod aimed at finding extrema as close as possible to the global maximum of\nthe gauge functional. We find finite volume effects to be small for the lattice\nsize $aL \\simeq 3$ fm at momenta $|p|\\, \\ge \\, 0.6$ GeV. For the same lattice\nsize we study extrapolations to the continuum limit of the ghost dressing\nfunction as well as for the running coupling with momenta chosen between $|p| =\n0.41$ GeV and $3.2$ GeV. We present fit formulae for the continuum limit of\nboth observables in this momentum range. Our results testify in favor of the\ndecoupling behavior in the infrared limit."
    },
    {
        "anchor": "Quenched Chiral Artifacts for Wilson-Dirac Fermions: We examine artifacts associated with the chiral symmetry breaking induced\nthrough the use of Wilson-Dirac fermions in lattice Monte Carlo computations.\nFor light quark masses, the conventional quenched theory can not be defined\nusing direct Monte Carlo methods due to the existence of nonintegrable poles in\nphysical quantities. These poles are associated with the real eigenvalue\nspectrum of the Wilson-Dirac operator. We show how this singularity structure\ncan be observed in the analysis of both QED in two dimensions and QCD in four\ndimensions.",
        "positive": "Hadronic corrections to the muon anomalous magnetic moment from lattice\n  QCD: After a brief self-contained introduction to the muon anomalous magnetic\nmoment, (g-2), we review the status of lattice calculations of the hadronic\nvacuum polarization contribution and present first results from lattice QCD for\nthe hadronic light-by-light scattering contribution. The signal for the latter\nis consistent with model calculations. While encouraging, the statistical error\nis large and systematic errors are mostly uncontrolled. The method is applied\nfirst to pure QED as a check."
    },
    {
        "anchor": "Zb tetraquark channel from lattice QCD and Born-Oppenheimer\n  approximation: Two $Z_b$ hadrons with exotic quark structure $\\bar bb\\bar du$ were\ndiscovered by Belle experiment. We present a lattice QCD study of the $\\bar\nbb\\bar du$ system in the approximation of static $b$ quarks, where the total\nspin of heavy quarks is fixed to one. The energies of eigenstates are\ndetermined as a function of the separation $r$ between $b$ and $\\bar b$. The\nlower eigenstates are related to a bottomonium and a pion. The eigenstate\ndominated by $B\\bar B^*$ has energy significantly below $m_B+m_{B^*}$, which\npoints to a sizable attraction for small $r$. The attractive potential $V(r)$\nbetween $B$ and $\\bar B^*$ is extracted assuming that this eigenstate is\nrelated exclusively to $B\\bar B^*$. The Schr\\\"odinger equation for $B\\bar B^*$\nwithin the extracted potential leads to one bound state below $B\\bar B^*$\nthreshold, whose mass depends on the parametrization of the lattice potential.\nFor certain parametrizations, the bound state is very close to the $B\\bar B^*$\nthreshold and renders a narrow peak in the $B\\bar B^*$ rate above threshold -\nthese features could be related to $Z_b(10610)$ in the experiment.",
        "positive": "Cooling, smearing and Dirac eigenmodes - A comparison of filtering\n  methods in lattice gauge theory: Starting from thermalized quenched SU(2) configurations we apply cooling or\niterated smearing, respectively, to produce sequences of gauge configurations\nwith less and less fluctuations. We compute the low lying spectrum and\neigenmodes of the lattice Dirac operator and compare them for the two types of\nsmoothing. Many characteristic properties of the eigensystem remain invariant\nfor all configurations in our sequences. We also find that cooling and smearing\nproduce surprisingly similar results. Both observations could be indications\nthat the two filtering methods do not drastically alter the long range\nstructures in the gauge field."
    },
    {
        "anchor": "The Wilson Flow and the finite temperature phase transition: We consider the determination of the finite temperature phase transition in\nthe Yang--Mills SU(3) gauge theory. We compute the difference of the spatial\nand temporal energy density at a physical Wilson flow time. This difference is\nzero in the confined phase and becomes non zero in the deconfined phase. We\nlocate the phase transition by using a new technique based on an exponential\nsmoothing spline. This method is an alternative to the determination of the\nphase transition based on the Polyakov loop susceptibility and can also be used\nwith dynamical fermions.",
        "positive": "K -> pi matrix elements of the chromagnetic operator on the lattice: We present preliminary results of the first lattice QCD calculation of the K\n-> pi matrix elements of the chromomagnetic operator O_{CM}=g sbar sigma_{munu}\nG_{munu} d, which appears in the effective Hamiltonian describing Delta S=1\ntransitions in and beyond the Standard Model. Having dimension 5, the\nchromomagnetic operator is characterized by a rich pattern of mixing with\noperators of equal and lower dimensionality. The multiplicative renormalization\nfactor as well as the mixing coefficients with the operators of equal dimension\nhave been computed at one-loop in perturbation theory. The power divergent\ncoefficients controlling the mixing with operators of lower dimension have been\ncomputed non-perturbatively, by imposing suitable subtraction conditions. The\nnumerical simulations have been carried out using the gauge field\nconfigurations produced by the European Twisted Mass Collaboration with\nN_f=2+1+1 dynamical quarks at three values of the lattice spacing. Our\npreliminary result for the B-parameter of the chromomagnetic operator is\nB_{CMO}=0.29(11), which can be compared with the estimate B_{CMO}~1-4 currently\nused in phenomenological analyses."
    },
    {
        "anchor": "Feynman-Hellmann theorem for resonances and the quest for QCD exotica: The generalization of the Feynman-Hellmann theorem for resonance states in\nquantum field theory is derived. On the basis of this theorem, a criterion is\nproposed to study the possible exotic nature of certain hadronic states\nemerging in QCD. It is shown that this proposal is supported by explicit\ncalculations in Chiral Perturbation Theory and by large-$N_c$ arguments.\nAnalyzing recent lattice data on the quark mass dependence in the pseudoscalar,\nvector meson, baryon octet and baryon decuplet sectors, we conclude that, as\nexpected, these are predominately quark-model states, albeit the corrections\nare non-negligible.",
        "positive": "Spherically-Symmetric Random Walks in Noninteger Dimension: A previous paper (hep-lat/9311011) proposed a new kind of random walk on a\nspherically-symmetric lattice in arbitrary noninteger dimension $D$. Such a\nlattice avoids the problems associated with a hypercubic lattice in noninteger\ndimension. This paper examines the nature of spherically-symmetric random walks\nin detail. We perform a large-time asymptotic analysis of these random walks\nand use the results to determine the Hausdorff dimension of the process. We\nobtain exact results in terms of Hurwitz functions (incomplete zeta functions)\nfor the probability of a walker going from one region of the spherical lattice\nto another. Finally, we show that the probability that the paths of $K$\nindependent random walkers will intersect vanishes in the continuum limit if\n$D> {{2K}\\over{K-1}}$."
    },
    {
        "anchor": "Lattice computation of structure functions: Recent lattice calculations of hadron structure functions are described.",
        "positive": "Renormalization group on a triad network: We propose a new renormalization scheme of tensor networks made only of third\norder tensors. The isometry used for coarse-graining the network can be\nprepared at an $O(D^6)$ computational cost in any $d$ dimension ($d \\ge 2$),\nwhere $D$ is the truncated bond dimension of tensors. Although it is reduced to\n$O(D^5)$ if a randomized singular value decomposition is employed, the total\ncost is $O(D^{d+3})$ because the contraction part for creating a renormalized\ntensor with isometries has $D^{d+3}$ multiplications. We test our method in\nthree dimensional Ising model and find that the numerical results are obtained\nfor large $D$s with reasonable errors."
    },
    {
        "anchor": "Fermionic Monte Carlo algorithms for lattice QCD: The increase with time of computer resources devoted to simulations of full\nQCD is spectacular. Yet the reduction of systematic errors is comparatively\nslow. This is due to the algorithmic complexity of the problem. I review, in\nelementary terms, the origin of this complexity, and estimate it for 3 exact\nfermion algorithms.",
        "positive": "Evidence for eta prime - pion splitting in unquenched lattice QCD: We perform an extrapolation from negative to positive flavour numbers of full\nQCD lattice estimates of the $\\eta'$ mass. The extrapolations are carried out\nby keeping $\\rho$ and $\\pi$ masses at fixed values. We find an $\\eta'$ -- $\\pi$\nsplitting which shows a flavour dependence consistent with the Witten Veneziano\nformula based on the $U(1)$ anomaly. The quantitative splitting is consistent\nwith the estimates made in the quenched approximation."
    },
    {
        "anchor": "Screening masses of mesons in 2+1 flavour QCD: We present results for screening masses of light and strange mesons in 2+1\nflavour QCD using improved (p4fat3) staggered fermions on 6x24^3 lattices. We\nhave studied the screening masses of scalar, pseudo-scalar, vector and\naxial-vector mesons along the line of constant physics, determined by a pion\nmass ~220 MeV and a kaon mass ~500 MeV. In order to investigate the cut-off and\nvolume dependencies we have also performed studies of the meson screening\ncorrelators in the non-interacting theory using the p4 and the standard\nstaggered discretizations.",
        "positive": "Non-Perturbative Approach to the Landau Gauge Gluodynamics: We discuss a non-perturbative lattice calculation of the ghost and gluon\npropagators in the pure Yang-Mills theory in Landau gauge. The ultraviolet\nbehaviour is checked up to NNNLO yielding the value\n$\\Lambda^{n_f=0}_{\\ms}=269(5)^{+12}_{-9}\\text{MeV}$, and we show that lattice\nGreen functions satisfy the complete Schwinger-Dyson equation for the ghost\npropagator for all considered momenta. The study of the above propagators at\nsmall momenta showed that the infrared divergence of the ghost propagator is\nenhanced, whereas the gluon propagator seem to remain finite and non-zero. The\nresult for the ghost propagator is consistent with the analysis of the\nSlavnov-Taylor identity, whereas, according to this analysis, the gluon\npropagator should diverge in the infrared, a result at odds with other\napproaches."
    },
    {
        "anchor": "Structure and transitions of nucleon excitations via parity-expanded\n  variational analysis: The recently-introduced Parity Expanded Variational Analysis (PEVA) technique\nallows for the isolation of baryon eigenstates on the lattice at finite\nmomentum free from opposite-parity contamination. We find that this technique\nintroduces a statistically significant correction in extractions of the\nelectromagnetic form factors of the ground state nucleon. It also allows first\nextractions of the elastic and transition form factors of nucleon excitations\non the lattice. We present the electromagnetic elastic form factors and\nhelicity amplitudes of two odd-parity excitations of the nucleon. These results\nprovide valuable insight into the structure of these states, and allow for a\nconnection to be made to quark-model states in this energy region.",
        "positive": "Unquenched quark propagator in Landau gauge: We present an unquenched calculation of the quark propagator in Landau gauge\nwith 2+1 flavors of dynamical quarks. We use configurations generated with an\nimproved staggered (``Asqtad'') action by the MILC collaboration. This quark\naction has been seen to have excellent rotational symmetry and scaling\nproperties in the quenched quark propagator. Quenched and dynamical\ncalculations are performed on a $20^3\\times 64$ lattice with a nominal lattice\nspacing of $a = 0.125$ fm. The matched quenched and dynamical lattices allow us\nto investigate the relatively subtle sea quark effects, and even in the\nquenched case the physical volume of these lattices gives access to lower\nmomenta than our previous study. We calculate the quark mass function and\nrenormalization function for a variety of valence and sea quark masses."
    },
    {
        "anchor": "Numerical study of the phase transitions in the two-dimensional Z(5)\n  vector model: We investigate the critical properties of the two-dimensional Z(5) vector\nmodel. For this purpose, we propose a new cluster algorithm, valid for Z(N)\nmodels with odd values of N. The two-dimensional Z(5) vector model is\nconjectured to exhibit two phase transitions with a massless intermediate\nphase. We locate the position of the critical points and study the critical\nbehavior across both phase transitions in details. In particular, we determine\nvarious critical indices and compare the results with analytical predictions.",
        "positive": "Current Status toward the Proton Mass Calculation in Lattice QCD: The proton mass calculation is still a tough challenge for lattice QCD. We\ndiscuss the current status and difficulties based on the recent PACS-CS results\nfor the hadron spectrum in 2+1 flavor QCD."
    },
    {
        "anchor": "London Penetration Length and String Tension in SU(2) Lattice Gauge\n  Theory: We study the distribution of the color fields due to a static quark-antiquark\npair in SU(2) lattice gauge theory. We find evidence of dual Meissner effect.\nWe put out a simple relation between the penetration length and the string\ntension.",
        "positive": "Kosterlitz-Thouless theory and lattice artifacts: The massive continuum limit of the 1+1 dimensional O(2) nonlinear\n$\\sigma$-model (XY model) is studied using its equivalence to the Sine-Gordon\nmodel at its asymptotically free point. It is shown that leading lattice\nartifacts are universal but they vanish only as inverse powers of the logarithm\nof the correlation length. Such leading artifacts are calculated for the case\nof the scattering phase shifts and the correlation function of the Noether\ncurrent using the bootstrap S-matrix and perturbation theory respectively."
    },
    {
        "anchor": "Quark-diquark potential and diquark mass from Lattice QCD: We propose a new application of lattice QCD to calculate the quark-diquark\npotential, diquark mass and quark mass required for the diquark model. As a\nconcrete example, we consider the $\\Lambda_c$ baryon and treat it as a\ncharm-diquark($c$-[$ud$]) two-body bound state. We extend the HAL QCD method to\ncalculate the charm-diquark potential which reproduces the equal-time\nNambu-Bethe-Salpeter wave function of the S-wave state\n($\\Lambda_c(\\frac12^+)$). The diquark mass is determined so as to reproduce the\ndifference between the S-wave and the spin-orbit averaged P-wave energies, i.e.\nthe difference between the $\\Lambda_c(\\frac12^+)$ level and the average of the\n$\\Lambda_c(\\frac12^-)$ and the $\\Lambda_c(\\frac32^-)$ levels. Numerical\ncalculations are performed on a $32^3\\times 64$ lattice with lattice spacing of\n$a \\simeq 0.0907$ fm and the pion mass of $m_{\\pi} \\simeq 700$ MeV. Our\ncharm-diquark potential is given by the Coulomb+linear (Cornell) potential\nwhere the long range behavior is consistent with the charm-anticharm potential\nwhile the Coulomb attraction is considerably smaller. This weakening of the\nattraction may be attributed to the diquark size effect. The obtained diquark\nmass is $m_D=1.273(44)$ GeV. Our diquark mass lies slightly above the\nconventional estimates, namely the $\\rho$ meson mass and twice the constituent\nquark mass $2m_N/3$.",
        "positive": "Progress in $Sp(2N)$ lattice gauge theories: Lattice studies of gauge theories with symplectic gauge groups provide\nvaluable information about gauge dynamics, and complement the results of\nlattice investigations focused on unitary gauge groups. These theories play a\ncentral role in phenomenological contexts such as composite Higgs and strongly\ninteracting dark matter models. We report on recent progress of our lattice\nresearch programme, starting from the glueball mass spectrum and the topology\nof the pure gauge theory. We present our results on the mass spectrum of mesons\nin the quenched approximation, by varying the number of colours in the\nsymplectic group. For the $Sp(4)$ theory, we focus on results obtained with\ndynamical fermion matter content comprising both fundamental and 2-index\nantisymmetric representations of the gauge group, as dictated by a well known\nmodel of composite Higgs with partial top compositeness."
    },
    {
        "anchor": "The pseudoparticle approach for solving path integrals in gauge theories: We present a numerical technique for calculating path integrals in\nnon-compact U(1) and SU(2) gauge theories. The gauge fields are represented by\na superposition of pseudoparticles of various types with their amplitudes and\ncolor orientations as degrees of freedom. Applied to Maxwell theory this\ntechnique results in a potential which is in excellent agreement with the\nCoulomb potential. For SU(2) Yang-Mills theory the same technique yields clear\nevidence of confinement. Varying the coupling constant exhibits the same\nscaling behavior for the string tension, the topological susceptibility and the\ncritical temperature while their dimensionless ratios are similar to those\nobtained in lattice calculations.",
        "positive": "The effect of tree-level and mean-field improvement on the light-hadron\n  spectrum in quenched QCD: We compute the light hadron mass spectrum at beta=5.7 using the O(a) improved\nSheikholeslami-Wohlert (SW) fermion action with two choices of the clover\ncoefficient: the classical value, c=1, and a mean-field or tadpole-improved\nestimate c=1.57. We compare our results with those of the GF11 Collaboration\nwho use the Wilson fermion action (c=0). We find that changing c from zero to 1\nand 1.57 leads to significant differences in the masses of the chirally\nextrapolated and strange pseudoscalar and vector mesons, the nucleon, the\nDelta, and also in the Edinburgh plot. A number of other quantities, for\nexample m_V^2-m_PS^2, J, am_K/am_\\rho and am_{K^*}/am_\\rho do not appear to\nchange significantly. We also investigate the effect of changing the lattice\nvolume from approximately (2 fm)^3 to (2.6 fm)^3. We find that the meson masses\nare consistent to within one standard deviation and baryon masses are\nconsistent to within two standard deviations."
    },
    {
        "anchor": "Resolving-Power Quantization: Starting with a general discussion, a program is sketched for a quantization\nbased on dilations. This resolving-power quantization is simplest for scalar\nfield theories. The hope is to find a way to relax the requirement of locality\nso that the necessity to fine tune mass parameters is eliminated while\nuniversality is still preserved.",
        "positive": "A local formulation of lattice Wess-Zumino model with exact $\\U(1)_R$\n  symmetry: A lattice Wess-Zumino model is formulated on the basis of Ginsparg-Wilson\nfermions. In perturbation theory, our formulation is equivalent to the\nformulation by Fujikawa and Ishibashi and by Fujikawa. Our formulation is,\nhowever, free from a singular nature of the latter formulation due to an\nadditional auxiliary chiral supermultiplet on a lattice. The model posssesses\nan exact $\\U(1)_R$ symmetry as a supersymmetric counterpart of the L\\\"uscher\nlattice chiral $\\U(1)$ symmetry. A restration of the supersymmetric\nWard-Takahashi identity in the continuum limit is analyzed in renormalized\nperturbation theory. In the one-loop level, a supersymmetric continuum limit is\nensured by suitably adjusting a coefficient of a single local term $\\tilde\nF^*\\tilde F$. The non-renormalization theorem holds to this order of\nperturbation theory. In higher orders, on the other hand, coefficents of local\nterms with dimension $\\leq4$ that are consistent with the $\\U(1)_R$ symmetry\nhave to be adjusted for a supersymmetric continuum limit. The origin of this\ncomplexicity in higher-order loops is clarified on the basis of the Reisz power\ncounting theorem. Therefore, from a view point of supersymmetry, the present\nformulation is not quite better than a lattice Wess-Zumino model formulated by\nusing Wilson fermions, although a number of coefficients which require\nadjustment is much less due to the exact $\\U(1)_R$ symmetry. We also comment on\nan exact non-linear fermionic symmetry which corresponds to the one studied by\nBonini and Feo; an existence of this exact symmetry itself does not imply a\nrestoration of supersymmetry in the continuum limit without any adjustment of\nparameters."
    },
    {
        "anchor": "Calorons with non-trivial holonomy on and off the lattice: We discuss recent solutions for SU(2) calorons with non-trivial holonomy at\nhigher charge, both through analytic means and using cooling, as well as\nextensive lattice studies for SU(3).",
        "positive": "Computing the long-distance contribution to the kaon mixing parameter\n  \u03b5_K: The largest contribution to the CP violating K_L-K_S mixing parameter\n\\epsilon_K comes from second order weak interactions at short distances and can\nbe accurately determined by a combination of electroweak perturbation theory\nand the calculation of the parameter B_K from lattice QCD. However, there is an\nadditional long distance contribution to \\epsilon_K which is estimated to be of\norder 5%. Here recently introduced lattice techniques for computing the\nlong-distance component of the K_L-K_S mass difference are generalized to this\nlong-distance contribution to \\epsilon_K."
    },
    {
        "anchor": "Masses, decay constants and electromagnetic form-factors with twisted\n  boundary conditions: We discuss some of the effects of twisted boundary conditions in finite\nvolume using continuum SU(3) Chiral Perturbation Theory. We point out how\nbroken cubic symmetry affects the definitions of quantities such as\nform-factors. Using the $\\pi^+$ as an example, we give one loop results for the\nmass, decay constants and electromagnetic form-factor and illustrate how the\nrelevant Ward identities are satisfied.",
        "positive": "On early onset of quark number density at zero temperature: We study a longstanding problem in lattice QCD at low temperature and nonzero\nquark chemical potential on an onset of the quark number density at\n$\\mu=m_\\pi/2$. We introduce a physical parametrization of the eigenvalues in\nthe reduction formula of the fermion determinant. It is shown that the\nparametrization reduces the quark number density operator to an expression with\nthe Fermi distribution of the quark. For each configuration, the eigenvalues of\nthe reduced matrix correspond to one-particle energy states of a quark. The gap\nof the eigenspectrum of the reduced matrix corresponds to the gap of the energy\nstates, which causes the $\\mu$-independence of the fermion determinant for\nsmall $\\mu$ at T=0. Once $\\mu$ exceeds the gap, the quark number density\nbecomes nonzero for each configuration, which causes the early onset of the\nquark number density."
    },
    {
        "anchor": "$B \\to D^{(*)}\\ell\u03bd$ form factors from $N_f\\!=\\!2+1$ QCD with M\u00f6bius\n  domain-wall quarks: We report on our study of the B \\to D^(*) \\ell \\nu semileptonic decays at\nzero and nonzero recoils in 2+1 flavor QCD. The M\\\"obius domain-wall action is\nemployed for light, charm and bottom quarks at lattice cutoffs 1/a = 2.5 and\n3.6 GeV. We take bottom quark masses up to \\approx 2.4 times the physical charm\nmass to control discretization effects. The pion mass is as low as M_\\pi \\sim\n310 MeV. We present our preliminary results for the relevant form factors and\ndiscuss the violation of heavy quark symmetry, which is a recent important\nisuue on the long-standing tension in the Cabibbo-Kobayashi-Maskawa matrix\nelement |V_{cb}| between the exclusive and inclusive decays.",
        "positive": "High density effective theory on the lattice: Long-range interactions in finite density QCD necessitate a non-perturbative\napproach in order to reliably map out the key features and spectrum of the QCD\nphase diagram. However, the complex nature of the fermion determinant in this\nsector prohibits the use of established Monte Carlo techniques that utilize\nimportance sampling. Whilst significant progress has been made in the low\ndensity, high temperature region, this remains a considerable challenge at mid\nto high density. At large chemical potential, QCD can be approximated using\nhigh density effective theory which is free from the sign problem at leading\norder. We investigate the implementation of this theory on the lattice in\nconjunction with existing re-weighting techniques."
    },
    {
        "anchor": "V_cs from D_s to \u03c6l\u03bd semileptonic decay and full lattice QCD: We determine the complete set of axial and vector form factors for the Ds to\n{\\phi}l{\\nu} decay from full lattice QCD for the first time. The valence quarks\nare implemented using the Highly Improved Staggered Quark action and we\nnormalise the appropriate axial and vector currents fully nonperturbatively.\nThe q^2 and angular distributions we obtain for the differential rate agree\nwell with those from the BaBar experiment and, from the total branching\nfraction, we obtain Vcs = 1.017(63), in good agreement with that from D to\nKl{\\nu} semileptonic decay. We also find the mass and decay constant of the\n{\\phi} meson in good agreement with experiment, showing that its decay to\nK{\\bar{K}} (which we do not include here) has at most a small effect. We\ninclude an Appendix on nonperturbative renormalisation of the complete set of\nstaggered vector and axial vector bilinears needed for this calculation.",
        "positive": "Chiral Limit and Light Quark Masses in 2+1 Flavor Domain Wall QCD: We present results for meson masses and decay constants measured on 24^3x64\nlattices using the domain wall fermion formulation with an extension of the\nfifth dimension of L_s=16 for N_f=2+1 dynamical quark flavors. The lightest\ndynamical meson mass in our set-up is around 331 MeV, while partially quenched\nmesons reach masses as low as 250 MeV. The applicability of SU(3)xSU(3) and\nSU(2)xSU(2) (partially quenched) chiral perturbation theory will be compared\nand we quote values for the low-energy constants from both approaches. We will\nextract the average light quark and strange quark masses and use a\nnon-perturbative renormalization technique (RI/MOM) to quote their physical\nvalues. The pion and kaon decay constants are determined at those values from\nour chiral fits and their ratio is used to obtain the CKM-matrix element\n|V_us|. The results presented here include statistical errors only."
    },
    {
        "anchor": "Generalized Parton Distributions from Lattice QCD with Asymmetric\n  Momentum Transfer: Unpolarized Quarks: Traditionally, lattice QCD computations of generalized parton distributions\n(GPDs) have been carried out in a symmetric frame, where the transferred\nmomentum is symmetrically distributed between the incoming and outgoing\nhadrons. However, such frames are inconvenient since they require a separate\ncalculation for each value of the momentum transfer, increasing significantly\nthe computational cost. In this work, by focusing on the quasi-distribution\napproach, we lay the foundation for faster and more effective lattice QCD\ncalculations of GPDs exploiting asymmetric frames, with freedom in the\ntransferred momentum distribution. An important ingredient of our approach is\nthe Lorentz covariant parameterization of the matrix elements in terms of\nLorentz-invariant amplitudes, which allows one to relate matrix elements in\ndifferent frames. We also use this amplitude approach to propose a new\ndefinition of quasi-GPDs that is frame-independent and, more importantly, may\nlead to smaller power corrections in the matching relations to the light-cone\nGPDs. We demonstrate the efficacy of the formalism through numerical\ncalculations using one ensemble of $N_f$=2+1+1 twisted mass fermions with a\nclover improvement. The value of the light-quark masses lead to a pion mass of\nabout 260 MeV. Concentrating on the proton, and limiting ourselves to a\nvanishing longitudinal momentum transfer to the target, we extract the\ninvariant amplitudes from matrix element calculations in both the symmetric and\nasymmetric frame, and obtain results for the twist-2 light-cone GPDs for\nunpolarized quarks, that is, $H$ and $E$.",
        "positive": "Constraining beyond the Standard Model nucleon isovector charges: At the TeV scale, low-energy precision observations of neutron\ncharacteristics provide unique probes of novel physics. Precision studies of\nneutron decay observables are susceptible to beyond the Standard Model (BSM)\ntensor and scalar interactions, while the neutron electric dipole moment,\n$d_n$, also has high sensitivity to new BSM CP-violating interactions. To fully\nutilise the potential of future experimental neutron physics programs, matrix\nelements of appropriate low-energy effective operators within neutron states\nmust be precisely calculated. We present results from the QCDSF/UKQCD/CSSM\ncollaboration for the isovector charges $g_T,~g_A$ and $g_S$ of the nucleon,\n$\\Sigma$ and $\\Xi$ baryons using lattice QCD methods and the Feynman-Hellmann\ntheorem. We use a flavour symmetry breaking method to systematically approach\nthe physical quark mass using ensembles that span five lattice spacings and\nmultiple volumes. We extend this existing flavour breaking expansion to also\naccount for lattice spacing and finite volume effects in order to quantify all\nsystematic uncertainties. Our final estimates of the nucleon isovector charges\nare\n$g_T~=~1.010(21)_{\\text{stat}}(12)_{\\text{sys}},~g_A=1.253(63)_{\\text{stat}}(41)_{\\text{sys}}$\nand $g_S~=~1.08(21)_{\\text{stat}}(03)_{\\text{sys}}$ renormalised, where\nappropriate, at $\\mu=2~\\text{GeV}$ in the $\\overline{\\text{MS}}$ scheme."
    },
    {
        "anchor": "Locality bound for effective four-dimensional action of domain-wall\n  fermion: We discuss locality in the domain-wall QCD through the effective\nfour-dimensional Dirac operator which is defined by the transfer matrix of the\nfive-dimensional Wilson fermion. We first derive an integral representation for\nthe effective operator, using the inverse five-dimensional Wilson-Dirac\noperator with the anti-periodic boundary condition in the fifth direction.\nExponential bounds are obtained from it for gauge fields with small lattice\nfield strength.",
        "positive": "Towards non-perturbative matching of three/four-flavor Wilson\n  coefficients with a position-space procedure: We propose a strategy to non-perturbatively match the Wilson coefficients in\nthe three- and four-flavor theories, which uses two-point Green's functions of\nthe corresponding four-quark operators at long distances. The idea is refined\nby combining with the spherical averaging technique, which enables us to\nconvert two-point functions calculated on the lattice into continuous functions\nof the distance $|x-y|$ between two operators. We also show the result for an\nexploratory calculation of two-point functions of the $\\Delta S=1$ operators\n$Q_7$ and $Q_8$ that are in the $(8_L,8_R)$ representation of ${\\rm\nSU(3)}_L\\times{\\rm SU(3)}_R$ and mix with each other."
    },
    {
        "anchor": "Evidence for a Center Vortex Origin of the Adjoint String Tension: Wilson loops in the adjoint representation are evaluated on cooled lattices\nin SU(2) lattice gauge theory. It is found that the string tension of an\nadjoint Wilson loop vanishes, if the loop is evaluated in a sub-ensemble of\nconfigurations in which no center vortex links the loop. This result supports\nour recent proposal that the adjoint string tension, in the Casimir-scaling\nregime, can be attributed to a center vortex mechanism.",
        "positive": "Radiative improvement of the lattice NRQCD action using the background\n  field method with applications to quarkonium spectroscopy: We apply the background field (BF) method to Non-Relativistic QCD (NRQCD) on\nthe lattice in order to determine the one-loop radiative corrections to the\ncoefficients of the NRQCD action in a manifestly gauge-covariant manner by\nmatching the NRQCD prediction for particular on-shell processes with those of\nrelativistic continuum QCD. We explain how the BF method is implemented in\nautomated perturbation theory and discuss the technique for matching the\nrelativistic and non-relativistic theories. We compute the one-loop radiative\ncorrections to the sigma.B and Darwin terms for the NRQCD action currently used\nin simulations, as well as the one-loop coefficients of the spin-dependent\nO(alpha^2) four-fermion contact terms. The effect of the corrections on the\nhyperfine splitting of bottomonium is estimated using earlier simulation\nresults; the corrected lattice prediction is found to be in agreement with\nexperiment. Agreement of the hyperfine splitting of bottomonium and the B-meson\nsystem is confirmed by recent simulation studies (Dowdall et al.) which include\nour NRQCD radiative corrections for the first time."
    },
    {
        "anchor": "The B -> pi l nu semileptonic form factor from three-flavor lattice QCD:\n  A model-independent determination of |V(ub)|: We calculate the form factor f_+(q^2) for B-meson semileptonic decay in\nunquenched lattice QCD with 2+1 flavors of light sea quarks. We use\nAsqtad-improved staggered light quarks and a Fermilab bottom quark on gauge\nconfigurations generated by the MILC Collaboration. We simulate with several\nlight quark masses and at two lattice spacings, and extrapolate to the physical\nquark mass and continuum limit using heavy-light meson staggered chiral\nperturbation theory. We then fit the lattice result for f_+(q^2) simultaneously\nwith that measured by the BABAR experiment using a parameterization of the form\nfactor shape in q^2 which relies only on analyticity and unitarity in order to\ndetermine the CKM matrix element |V(ub)|. This approach reduces the total\nuncertainty in |V(ub)| by combining the lattice and experimental information in\nan optimal, model-independent manner. We find a value of |V(ub)| x 10^3 = 3.38\n+/- 0.36.",
        "positive": "Strange and charm quark contributions to the anomalous magnetic moment\n  of the muon: We describe a new technique to determine the contribution to the anomalous\nmagnetic moment of the muon coming from the hadronic vacuum polarization using\nlattice QCD. Our method reconstructs the Adler function, using Pad\\'{e}\napproximants, from its derivatives at $q^2=0$ obtained simply and accurately\nfrom time-moments of the vector current-current correlator at zero spatial\nmomentum. We test the method using strange quark correlators on large-volume\ngluon field configurations that include the effect of up and down (at physical\nmasses), strange and charm quarks in the sea at multiple values of the lattice\nspacing and multiple volumes and show that 1% accuracy is achievable. For the\ncharm quark contributions we use our previously determined moments with up,\ndown and strange quarks in the sea on very fine lattices. We find the\n(connected) contribution to the anomalous moment from the strange quark vacuum\npolarization to be $a_\\mu^s = 53.41(59) \\times 10^{-10}$, and from charm to be\n$a_\\mu^c = 14.42(39)\\times 10^{-10}$. These are in good agreement with\nflavour-separated results from non-lattice methods, given caveats about the\ncomparison. The extension of our method to the light quark contribution and to\nthat from the quark-line disconnected diagram is straightforward."
    },
    {
        "anchor": "Reaching the continuum limit in lattice gauge theory - without a\n  computer: The scaling slope of the anti-symmetric mass gap M of compact U(1)_{2+1}\nlattice gauge theory is obtained analytically in the Hamiltonian formalism\nusing the plaquette expansion. Based on the first four moments of the\nHamiltonian with respect to a one-plaquette mean field state the results\ndemonstrate clear scaling of M at and beyond the transition from strong to weak\ncoupling. The scaling parameters determined agree well with the range of\nnumerical determinations available.",
        "positive": "Improved actions and asymptotic scaling in lattice Yang-Mills theory: Improved actions in SU(2) and SU(3) lattice gauge theories are investigated\nwith an emphasis on asymptotic scaling. A new scheme for tadpole improvement is\nproposed. The standard but heuristic tadpole improvement emerges from a mean\nfield approximation from the new approach. Scaling is investigated by means of\nthe large distance static quark potential. Both, the generic and the new\ntadpole scheme yield significant improvements on asymptotic scaling when\ncompared with loop improved actions. A study of the rotational symmetry\nbreaking terms, however, reveals that only the new improvement scheme\nefficiently eliminates the leading irrelevant term from the action."
    },
    {
        "anchor": "Phase transitions in heavy-quark QCD from an effective theory: With combined hopping parameter and strong coupling expansions, we calculate\na dimensionally reduced Polyakov-loop effective theory valid for heavy quarks\nat nonzero temperature and arbitrary chemical potential. We numerically compute\nthe critical endpoint of the deconfinement transition as a function of quark\nmasses and number of flavours. We also investigate the applicability of the\nmodel to the low-T and high density region, specifically in terms of baryon\ncondensation phenomena.",
        "positive": "Effective potential for Polyakov loops from a center symmetric effective\n  theory in three dimensions: We present lattice simulations of a center symmetric dimensionally reduced\neffective field theory for SU(2) Yang Mills which employ thermal Wilson lines\nand three-dimensional magnetic fields as fundamental degrees of freedom. The\naction is composed of a gauge invariant kinetic term, spatial gauge fields and\na potential for the Wilson line which includes a \"fuzzy\" bag term to generate\nnon-perturbative fluctuations. The effective potential for the Polyakov loop is\nextracted from the simulations including all modes of the loop as well as for\ncooled configuration where the hard modes have been averaged out. The former is\nfound to exhibit a non-analytic contribution while the latter can be described\nby a mean-field like ansatz with quadratic and quartic terms, plus a\nVandermonde potential which depends upon the location within the phase diagram."
    },
    {
        "anchor": "Nonperturbative beta function of twelve-flavor SU(3) gauge theory: We study the discrete beta function of SU(3) gauge theory with Nf=12 massless\nfermions in the fundamental representation. Using an nHYP-smeared staggered\nlattice action and an improved gradient flow running coupling $\\tilde g_c^2(L)$\nwe determine the continuum-extrapolated discrete beta function up to $g_c^2\n\\approx 8.2$. We observe an IR fixed point at $g_{\\star}^2 =\n7.3\\left(_{-2}^{+8}\\right)$ in the $c = \\sqrt{8t} / L = 0.25$ scheme, and\n$g_{\\star}^2 = 7.3\\left(_{-3}^{+6}\\right)$ with c=0.3, combining statistical\nand systematic uncertainties in quadrature. The systematic effects we\ninvestigate include the stability of the $(a / L) \\to 0$ extrapolations, the\ninterpolation of $\\tilde g_c^2(L)$ as a function of the bare coupling, the\nimprovement of the gradient flow running coupling, and the discretization of\nthe energy density. In an appendix we observe that the resulting systematic\nerrors increase dramatically upon combining smaller $c \\lesssim 0.2$ with\nsmaller $L \\leq 12$, leading to an IR fixed point at $g_{\\star}^2 = 5.9(1.9)$\nin the c=0.2 scheme, which resolves to $g_{\\star}^2 =\n6.9\\left(_{-1}^{+6}\\right)$ upon considering only $L \\geq 16$. At the IR fixed\npoint we measure the leading irrelevant critical exponent to be\n$\\gamma_g^{\\star} = 0.26(2)$, comparable to perturbative estimates.",
        "positive": "Random Matrices and the Convergence of Partition Function Zeros in\n  Finite Density QCD: We apply the Glasgow method for lattice QCD at finite chemical potential to a\nschematic random matrix model (RMM). In this method the zeros of the partition\nfunction are obtained by averaging the coefficients of its expansion in powers\nof the chemical potential. In this paper we investigate the phase structure by\nmeans of Glasgow averaging and demonstrate that the method converges to the\ncorrect analytically known result. We conclude that the statistics needed for\ncomplete convergence grows exponentially with the size of the system, in our\ncase, the dimension of the Dirac matrix. The use of an unquenched ensemble at\n$\\mu=0$ does not give an improvement over a quenched ensemble.\n  We elucidate the phenomenon of a faster convergence of certain zeros of the\npartition function. The imprecision affecting the coefficients of the\npolynomial in the chemical potential can be interpeted as the appearance of a\nspurious phase. This phase dominates in the regions where the exact partition\nfunction is exponentially small, introducing additional phase boundaries, and\nhiding part of the true ones. The zeros along the surviving parts of the true\nboundaries remain unaffected."
    },
    {
        "anchor": "Universal properties of Wilson loop operators in large N QCD: Eigenvalues of a Wilson loop operator are gauge invariant and their\ndistribution undergoes a transition at infinite N as the size of the loop is\nchanged. We study this transition using the average characteristic polynomial\nassociated with the Wilson loop operator. We derive the scaling function in a\ncertain double scaling limit for two dimensional QCD and hypothesize that the\ntransition in three and four dimensional QCD are in the same universality\nclass. Numerical evidence for this hypothesisis provided in three dimensions",
        "positive": "Entropy per Baryon in Strong Coupling QCD: The entropy per baryon is studied in the strong coupling large dimension $d$\nlimit of lattice QCD with staggered fermions. The partition function is\ncalculated for non-zero chemical potential and temperature using the $1/d$\nexpansion. It is found that the entropy per baryon ratio is almost continuous\nacross the transition from the the quark-gluon to the hadronic phase. The\nrelevance of these results for heavy ion collisions is discussed."
    },
    {
        "anchor": "Lattice QCD calculation of the electroweak box diagrams for the kaon\n  semileptonic decays: We present a lattice QCD calculation of the axial $\\gamma W$-box diagrams\nrelevant for the kaon semileptonic decays. We utilize a recently proposed\nmethod, which connects the electroweak radiative corrections in Sirlin's\nrepresentation to that in chiral perturbation theory. It allows us to use the\naxial $\\gamma W$-box correction in the SU(3) limit to obtain the low energy\nconstants for chiral perturbation theory. From first principles our results\nconfirm the previously used low energy constants provided by the minimal\nresonance model with a significant reduction in uncertainties.",
        "positive": "BSM $B - \\bar{B}$ mixing on JLQCD and RBC/UKQCD $N_f=2+1$ DWF ensembles: We are presenting our ongoing Lattice QCD study on $B - \\bar{B}$ mixing on\nseveral RBC/UKQCD and JLQCD ensembles with 2+1 dynamical-flavour domain-wall\nfermions, including physical-pion-mass ensembles. We are extracting bag\nparameters $B_{B_d}$ and $B_{B_s}$ using the full 5-mixing-operator basis to\nstudy both Standard-Model mixing as well as Beyond the Standard Model mixing,\nusing a fully correlated combined fit to two-point functions and ratios of\nthree-point and two-point functions. Using 15 different lattice ensembles we\nare simulating a range of heavy-quark masses from below the charm-quark mass to\njust below the bottom-quark mass."
    },
    {
        "anchor": "Predictions of chiral random matrix theory and lattice QCD results: Chiral random matrix theory makes very detailed predictions for the spectral\ncorrelations of the QCD Dirac operator, both in the bulk of the spectrum and\nnear zero virtuality. These predictions have been successfully tested in\nlattice QCD simulations by several groups. Moreover, the domain of validity of\nrandom matrix theory has been predicted theoretically and identified in lattice\ndata. In this talk, the current numerical evidence is reviewed.",
        "positive": "Pure gauge QCD flux tubes and their widths at finite temperature: We study the flux tubes produced by static quark-antiquark, quark-quark and\nquark-gluon charges at finite temperature in pure gauge SU(3) lattice QCD. Our\nsources are static and our lattice correlators are composed of fundamental and\nadjoint Polyakov loops. To signal the flux tubes, we compute the square\ndensities of the chromomagnetic and chromoelectric fields with plaquettes, in a\ngauge invariant framework. We study the existence and non-existence of flux\ntubes both above and below the deconfinement phase transition temperature Tc.\nUsing the Lagrangian density as a probability distribution, we also compute the\nwidths of the flux tubes and study their widening as a function of the\nintercharge distance. We determine our results with both statistical and\nsystematic errors. Our computations are performed in NVIDIA GPUs using the CUDA\nlanguage."
    },
    {
        "anchor": "Chiral anomalies and rooted staggered fermions: A popular approximation in lattice gauge theory is an extrapolation in the\nnumber of fermion species away from the four fold degeneracy natural with the\nstaggered fermion formulation. I show that the extrapolation procedure\nmutilates the expected continuum holomorphic behavior in the quark masses. The\nconventional resolution proposes canceling the unphysical singularities with a\nplethora of extra states appearing at finite lattice spacing. This unproven\nconjecture requires an explicit loss of unitarity and locality. Even if\ncorrect, the approach implies large cutoff effects in the low-energy\nflavor-neutral sector.",
        "positive": "Nonperturbative renormalization of composite operators with overlap\n  fermions: We compute non-perturbatively the renormalization constants of composite\noperators on a quenched $16^3 \\times 28 $ lattice with lattice spacing $a$ =\n0.20 fm for the overlap fermion by using the regularization independent (RI)\nscheme. The quenched gauge configurations were generated with the Iwasaki\naction. We test the relations $Z_A = Z_V$ and $ Z_S=Z_P$ and find that they\nagree well {(less than 1%)} above $\\mu$ = 1.6 GeV. %even for our lattice with a\ncoarse lattice spacing. We also perform a Renormalization Group (RG) analysis\nat the next-to-next-to-leading order and match the renormalization constants to\nthe $\\bar{\\rm MS}$ scheme. The wave-function renormalization $Z_{\\psi}$ is\ndetermined from the vertex function of the axial current and $Z_A$ from the\nchiral Ward identity. Finally, we examine the finite quark mass behavior for\nthe renormalization factors of the quark bilinear operators. We find that the\n$(pa)^2$ errors of the vertex functions are small and the quark mass dependence\nof the renormalization factors to be quite weak."
    },
    {
        "anchor": "Baryonic thermal fluctuations in finite temperature QCD: We show how, contrary to physical intuition, thermal fluctuations of physical\nstates having a non-vanishing baryonic number can be fully neglected in the\nthermodynamics of QCD at any physical temperature. We also discuss on the\nconsistency between our results and the CPT theorem. The last part of this\narticle is devoted to comment some interesting physical features which follow\nfrom this result.",
        "positive": "Solving the left-hand cut problem in lattice QCD: $T_{cc}(3875)^+$ from\n  finite volume energy levels: A novel effective-field-theory-based approach is implemented for extracting\ntwo-body scattering information from finite volume energies, serving as an\nalternative to L\\\"uscher's method. By explicitly incorporating one-pion\nexchange, the approach quantitatively accounts for effects related to left-hand\ncuts and range corrections from the longest-range interactions. The method\nutilizes the plane wave basis instead of the conventional partial wave\nexpansion, thereby also naturally including partial wave mixing effects\nresulting from rotational symmetry breaking in a cubic box. Applied to the\nlattice data for $DD^*$ scattering at a pion mass of 280 MeV, it reveals the\nsignificant impact of the one-pion exchange on P-wave and S-wave phase shifts.\nThe pole position of the $T_{cc}(3875)^+$ state, extracted from the\nfinite-volume energy levels while taking into account left-hand cut effects,\nrange corrections, and partial-wave mixing, appears to be consistent with a\nnear-threshold resonance."
    },
    {
        "anchor": "Power-counting theorem for staggered fermions: Lattice power-counting is extended to QCD with staggered fermions. As\npreparation, the difficulties encountered by Reisz's original formulation of\nthe lattice power-counting theorem are illustrated. One of the assumptions that\nis used in his proof does not hold for staggered fermions, as was pointed out\nlong ago by Luscher. Finally, I generalize the power-counting theorem, and the\nmethods of Reisz's proof, such that the difficulties posed by staggered\nfermions are overcome.",
        "positive": "Absence of Physical Walls in Hot Gauge Theories: This paper shows that there are no physical walls in the deconfined,\nhigh-temperature phase of Z(2) lattice gauge theory. In a Hamiltonian\nformulation, the interface in the Wilson lines is not physical. The line\ninterface and its energy are interpreted in terms of physical variables. They\nare associated with a difference between two partition functions. One includes\nonly the configurations with even flux across the interface. The other is\nrestricted to odd flux."
    },
    {
        "anchor": "Improved data analysis on two-point correlation function with sequential\n  Bayesian method: We report our progress in data analysis on two-point correlation functions of\nthe $B$ meson using sequential Bayesian method. The data set of measurement is\nobtained using the Oktay-Kronfeld (OK) action for the bottom quarks (valence\nquarks) and the HISQ action for the light quarks on the MILC HISQ lattices. We\nfind that the old initial guess for the $\\chi^2$ minimizer in the fitting code\nis poor enough to slow down the analysis somewhat. In order to find a better\ninitial guess, we adopt the Newton method. We find that the Newton method\nprovides a natural test to check whether the $\\chi^2$ minimizer finds a local\nminimum or the global minimum, and it also reduces the number of iterations\ndramatically.",
        "positive": "Lattice Simulations using OpenACC compilers: OpenACC compilers allow one to use Graphics Processing Units without having\nto write explicit CUDA codes. Programs can be modified incrementally using\nOpenMP like directives which causes the compiler to generate CUDA kernels to be\nrun on the GPUs. In this article we look at the performance gain in lattice\nsimulations with dynamical fermions using OpenACC compilers."
    },
    {
        "anchor": "Chiral condensate in nf=2 QCD from the Banks-Casher relation: Exploiting the Banks-Casher relation, we present a direct determination of\nthe chiral condensate in two-flavor QCD, computing the mode number of the\nO(a)-improved Wilson-Dirac operator below various cutoffs. We make use of\nCLS-configurations with three different lattice spacings in the range of\n0.05-0.08 fm and pion masses down to 190 MeV. Our data indicate a non-zero\ndensity of eigenmodes near the origin and hence points to spontaneous chiral\nsymmetry breaking. We extrapolate our results to the continuum and chiral limit\nto give a result for the chiral condensate.",
        "positive": "Exploring interpolating momentum schemes: We compute the renormalisation factors of the quark mass and wave function\nusing IMOM (Interpolating MOMenta) schemes. The framework is the\nRome-Southampton non-renormalisation method, but the momentum transfer in the\nquark bilinears is not restricted to zero or to the symmetric point. We study\nthe scale dependence, infrared contamination and lattice artefacts for\ndifferent values of this momentum transfer and for two different kinds of\nprojectors. For the numerical simulations, we use data generated by the\nRBC-UKQCD collaborations, with $N_f = 2+1$ flavours of Domain-Wall fermions,\nand inverse lattice spacing of $1.79 $ and $2.38$ GeV."
    },
    {
        "anchor": "The overlap operator as a continued fraction: We use a continued fraction expansion of the sign-function in order to obtain\na five dimensional formulation of the overlap lattice Dirac operator. Within\nthis formulation the inverse of the overlap operator can be calculated by a\nsingle Krylov space method where nested conjugate gradient procedures are\navoided. We show that the five dimensional linear system can be made well\nconditioned using equivalence transformations on the continued fractions. This\nis of significant importance when dynamical overlap fermions are simulated.",
        "positive": "Restless pions from orbifold boundary conditions: an explicit\n  construction for noise reduction in lattice QCD: The exponentially decreasing signal to noise ratio in multibaryon correlators\nis the main obstacle to a first principles, QCD-based calculation of the\nnuclear force. Recently, we have proposed an orbifold boundary condition\n(\"restless pions\") that can dramatically improve this matter. Here we develop\nthe idea further by proposing an explicit algorithm that can be used with\npurely periodic, \"off the shelf\" gauge configurations. We also discuss finite\nvolume corrections with the new boundary conditions and the use of the \"Luscher\nformula'' for the phase shifts."
    },
    {
        "anchor": "Elastic nucleon-pion scattering at $m_\u03c0 = 200~{\\rm MeV}$ from\n  lattice QCD: Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on\na single ensemble of gauge field configurations with $N_{\\rm f} = 2+1$\ndynamical quark flavors and $m_{\\pi} = 200~{\\rm MeV}$. The $s$-wave scattering\nlengths with both total isospins $I=1/2$ and $I=3/2$ are inferred from the\nfinite-volume spectrum below the inelastic threshold together with the $I=3/2$\n$p$-wave containing the $\\Delta(1232)$ resonance. The amplitudes are\nwell-described by the effective range expansion with parameters constrained by\nfits to the finite-volume energy levels enabling a determination of the $I=3/2$\nscattering length with statistical errors below $5\\%$, while the $I = 1/2$ is\nsomewhat less precise. Systematic errors due to excited states and the\ninfluence of higher partial waves are controlled, providing a pathway for\nfuture computations down to the physical light quark masses with multiple\nlattice spacings and physical volumes.",
        "positive": "Non-perturbative improvement of the axial current with three dynamical\n  flavors and the Iwasaki gauge action: We perform a non-perturbative determination of the improvement coefficient\nc_A to remove O(a) discretization errors in the axial vector current in\nthree-flavor lattice QCD with the Iwasaki gauge action and the standard\nO$(a)$-improved Wilson quark action. An improvement condition with a good\nsensitivity to c_A is imposed at constant physics. Combining our results with\nthe perturbative expansion, c_A is now known rather precisely for 1/a \\gtrsim\n1.6 GeV."
    },
    {
        "anchor": "Light quark masses from Domain Wall Fermions: We present results for the renormalised light and strange quark masses\ncalculated using Domain Wall Fermions in quenched QCD. New results using the\nDBW2 gauge action at inverse lattice spacings of approximately 2 GeV and 1.3\nGeV will be presented and compared against existing results at 2 GeV using the\nWilson gauge action. This comparison allows a study of the uncertainties due to\nboth finite lattice spacing and residual chiral symmetry breaking effects.",
        "positive": "Multi-particle systems on the lattice and chiral extrapolations: a brief\n  review: The extraction of two- and three-body hadronic scattering amplitudes and the\nproperties of the low-lying hadronic resonances from the finite-volume energy\nlevels in lattice QCD represents a rapidly developing field of research. The\nuse of various modifications of the L\\\"uscher finite-volume method has opened a\npath to calculate infinite-volume scattering amplitudes on the lattice. Many\nnew results have been obtained recently for different two- and three-body\nscattering processes, including the extraction of resonance poles and their\nproperties from lattice data. Such studies, however, require robust\nparametrizations of the infinite-volume scattering amplitudes, which rely on\nbasic properties of $S$-matrix theory and -- preferably -- encompass systems\nwith quark masses at and away from the physical point. Parametrizations of this\nkind, provided by unitarized Chiral Perturbation Theory, are discussed in this\nreview. Special attention is paid to three-body systems on the lattice, owing\nto the rapidly growing interest in the field. Here, we briefly survey the\nformalism, chiral extrapolation, as well as finite-volume analyses of lattice\ndata."
    },
    {
        "anchor": "The critical points of lattice QCD with a non--zero quark density: We study the interplay of quark number density and chiral symmetry in lattice\nQCD. We suggest that both are controlled by the eigenvalue spectrum of the\nfermionic propagator matrix, which shapes the pattern of zeros of the partition\nfunction. The onset of the quark current would be triggered by the lowest lying\neigenvalue, the chiral transition by the density of zeros, the two critical\npoints being distinct in full QCD, and coincident in the quenched\napproximation. Our preliminary estimate for the critical point in full QCD in\nthe infinite couling limit compares favourably with the predictions of the\nstrong coupling expansions and of numerical simulations based on exact,\nalternative representations of the partition function. Several reasons of\nperplexity however remain, which are briefly discussed.",
        "positive": "Mean link versus average plaquette tadpoles in lattice NRQCD: We compare mean-link and average plaquette tadpole renormalization schemes in\nthe context of the quarkonium hyperfine splittings in lattice NRQCD.\nSimulations are done for the three quarkonium systems $c\\bar c$, $b\\bar c$, and\n$b\\bar b$. The hyperfine splittings are computed both at leading and at\nnext-to-leading order in the relativistic expansion. Results are obtained at a\nlarge number of lattice spacings. A number of features emerge, all of which\nfavor tadpole renormalization using mean links. This includes much better\nscaling of the hyperfine splittings in the three quarkonium systems. We also\nfind that relativistic corrections to the spin splittings are smaller with\nmean-link tadpoles, particularly for the $c\\bar c$ and $b\\bar c$ systems. We\nalso see signs of a breakdown in the NRQCD expansion when the bare quark mass\nfalls below about one in lattice units (with the bare quark masses turning out\nto be much larger with mean-link tadpoles)."
    },
    {
        "anchor": "Enumerating Gribov copies on the lattice: In the modern formulation of lattice gauge-fixing, the gauge fixing condition\nis written in terms of the minima or stationary points (collectively called\nsolutions) of a gauge-fixing functional. Due to the non-linearity of this\nfunctional, it usually has many solutions called Gribov copies. The dependence\nof the number of Gribov copies, n[U] on the different gauge orbits plays an\nimportant role in constructing the Faddeev-Popov procedure and hence in\nrealising the BRST symmetry on the lattice. Here, we initiate a study of\ncounting n[U] for different orbits using three complimentary methods: 1.\nanalytical results in lower dimensions, and some lower bounds on n[U] in higher\ndimensions, 2. the numerical polynomial homotopy continuation method, which\nnumerically finds all Gribov copies for a given orbit for small lattices, and\n3. numerical minimisation (\"brute force\"), which finds many distinct Gribov\ncopies, but not necessarily all. Because n for the coset SU(N_c)/U(1) of an\nSU(N_c) theory is orbit-independent, we concentrate on the residual compact\nU(1) case in this article and establish that n is orbit-dependent for the\nminimal lattice Landau gauge and orbit-independent for the absolute lattice\nLandau gauge. We also observe that contrary to a previous claim, n is not\nexponentially suppressed for the recently proposed stereographic lattice Landau\ngauge compared to the naive gauge in more than one dimension.",
        "positive": "Static-light matrix elements on a dynamical anisotropic lattice: The static-light matrix element needed to determine $f_B$ is studied on an\nanisotropic lattice with $N_f=2$. The improvement in precision due to stout\nlinks and all-to-all propagators is investigated."
    },
    {
        "anchor": "Excited State Spectroscopy in the Lattice Gross-Neveu Model: We present preliminary results of an excited state spectroscopy calculation\nin the 2-d lattice Gross-Neveu model. We address the construction of suitable\ninterpolators for the variational method and their overlap with excitations. We\ncomment on the role of the eigenvectors as a tool for matching scattering\nstates on lattices with different volumes.",
        "positive": "Hadron masses on a 16^3 x 40 lattice at \u03b2= 5.7: We report on the hadron mass spectrum obtained on a 16^3 x 40 lattice in full\nQCD at \\beta = 5.7 using two flavors of staggered fermions with m a = 0.01. We\nstudy the effective mass plateaus for different sized sources. Our mass results\nare slightly lighter than our earlier 16^3 x 32 calculation. The Landau gauge\n\\Delta is quite different from the Coulomb gauge \\Delta."
    },
    {
        "anchor": "Flavor Twisted Boundary Conditions, Pion Momentum, and the Pion\n  Electromagnetic Form Factor: We investigate the utility of partially twisted boundary conditions in\nlattice calculations of meson observables. For dynamical simulations, we show\nthat the pion dispersion relation is modified by volume effects. In the isospin\nlimit, we demonstrate that the pion electromagnetic form factor can be computed\non the lattice at continuous values of the momentum transfer. Furthermore, the\nfinite volume effects are under theoretical control for extraction of the pion\ncharge radius.",
        "positive": "Matter-Antimatter Coexistence Method for Finite Density QCD: We propose a \"matter-antimatter coexistence method\" for finite-density\nlattice QCD, aiming at a possible solution of the sign problem. In this method,\nwe consider matter and anti-matter systems on two parallel ${\\bf R}^4$-sheets\nin five-dimensional Euclidean space-time. For the matter system $M$ with a\nchemical potential $\\mu \\in {\\bf C}$ on a ${\\bf R}^4$-sheet, we also prepare\nthe anti-matter system $\\bar M$ with $-\\mu^*$ on the other ${\\bf R}^4$-sheet\nshifted in the fifth direction. In the lattice QCD formalism, we introduce a\ncorrelation term between the gauge variables $U_\\nu \\equiv e^{iagA_\\nu}$ in $M$\nand $\\tilde U_\\nu \\equiv e^{iag \\tilde A_\\nu}$ in $\\bar M$, such as $S_\\lambda\n\\equiv \\sum_{x,\\nu} 2\\lambda \\{N_c-{\\rm Re~tr} [U_\\nu(x) \\tilde\nU_\\nu^\\dagger(x)]\\} \\simeq \\sum_x \\frac{1}{2}\\lambda a^2 \\{A_\\nu^a(x)-\\tilde\nA_\\nu^a(x)\\}^2$ with a real parameter $\\lambda$. In the limit of $\\lambda\n\\rightarrow \\infty$, a strong constraint $\\tilde U_\\nu(x)=U_\\nu(x)$ is\nrealized, and the total fermionic determinant is real and non-negative. In the\nlimit of $\\lambda \\rightarrow 0$, this system goes to two separated ordinary\nQCD systems with the chemical potential of $\\mu$ and $-\\mu^*$. On a\nfinite-volume lattice, if one takes an enough large value of $\\lambda$, $\\tilde\nU_\\nu(x) \\simeq U_\\nu(x)$ is realized and there occurs a phase cancellation\napproximately between two fermionic determinants in $M$ and $\\bar M$, which is\nexpected to suppress the sign problem and to make the lattice calculation\npossible. For the obtained gauge configurations of the coexistence system,\nmatter-side quantities are evaluated through their measurement only for the\nmatter part $M$. By the calculations with gradually decreasing $\\lambda$ and\ntheir extrapolation to $\\lambda=0$, physical quantities in finite density QCD\nare expected to be estimated."
    },
    {
        "anchor": "Relativistic, model-independent, multichannel $2\\to2$ transition\n  amplitudes in a finite volume: We derive formalism for determining $\\textbf{2} + \\mathcal J \\to \\textbf{2}$\ninfinite-volume transition amplitudes from finite-volume matrix elements.\nSpecifically, we present a relativistic, model-independent relation between\nfinite-volume matrix elements of external currents and the physically\nobservable infinite-volume matrix elements involving two-particle asymptotic\nstates. The result presented holds for states composed of two scalar bosons.\nThese can be identical or non-identical and, in the latter case, can be either\ndegenerate or non-degenerate. We further accommodate any number of\nstrongly-coupled two-scalar channels. This formalism will, for example, allow\nfuture lattice QCD calculations of the $\\rho$-meson form factor, in which the\nunstable nature of the $\\rho$ is rigorously accommodated.",
        "positive": "Flavor non-singlet parton distribution functions from lattice QCD at\n  physical quark masses via the pseudo-distribution approach: One of the great challenges of QCD is to determine the partonic structure of\nthe nucleon from first principles. In this work, we provide such a\ndetermination of the flavor non-singlet ($u-d$) unpolarized parton distribution\nfunction (PDF), utilizing the non-perturbative formulation of QCD on the\nlattice. We apply Radyushkin's pseudo-distribution approach to lattice results\nobtained using simulations with the light quark mass fixed to its physical\nvalue; this is the first ever attempt for this approach directly at the\nphysical point. The extracted coordinate-space matrix elements are used to find\nthe relevant physical Ioffe time distributions from a matching procedure. The\nfull Bjorken-$x$ dependence of PDFs is resolved using several reconstruction\nmethods to tackle the ill-conditioned inverse problem encountered when using\ndiscrete lattice data. We consider both the valence distribution $q_v$ and the\ncombination with antiquarks $q_v+2\\bar{q}$, related to, respectively, the real\nand imaginary part of extracted matrix elements. Good agreement is found with\nPDFs from global fits already within statistical uncertainties and it is\nfurther improved by quantifying several systematic effects. The results\npresented here are the first ever \\emph{ab initio} determinations of PDFs fully\nconsistent with global fits in the whole $x$-range. Thus, they pave the way to\ninvestigating a wider class of partonic distributions, such as e.g.\\ singlet\nPDFs and generalized parton distributions. Therefore, essential and yet missing\nfirst-principle insights can be achieved, complementing the rich experimental\nprograms dedicated to the structure of the nucleon."
    },
    {
        "anchor": "K0-K0bar on the Lattice: I review recent lattice calculations performed with Nf=2 and Nf=2+1 dynamical\nfermions which provide a precise computation of the BK bag parameter. I also\nreport on Nf=2 dynamical quark simulations aiming at the computation of the\nfull basis of the Delta_S=2 four-fermion operator matrix elements that are\nrelevant to models beyond the Standard Model.",
        "positive": "Determination of the light, strange and charm quark masses using twisted\n  mass fermions: We present results for the light, strange and charm quark masses using\n$N_f=2+1+1$ twisted mass fermion ensembles at three values of the lattice\nspacing, including two ensembles simulated with the physical value of the pion\nmass. The analysis is done both in the meson and baryon sectors. The difference\nin the mean values found in the two sectors is included as part of the\nsystematic error. The presentation is based on the work of Ref. [1], where more\ndetails can be found."
    },
    {
        "anchor": "Systematic errors of L\u00fcscher's fermion method and its extensions: We study the systematic errors of L\\\"uscher's formulation of dynamical Wilson\nquarks and some of its variants, in the weak and strong coupling limits, and on\na sample of small configurations at finite $\\beta$. We confirm the existence of\nan optimal window in the cutoff parameter $\\varepsilon$, and the exponential\ndecrease of the error with the number of boson families. A non-hermitian\nvariant improves the approximation further and allows for an odd number of\nflavors. A simple and economical Metropolis test is proposed, which makes the\nalgorithm exact.",
        "positive": "Prospects for a lattice computation of rare kaon decay amplitudes II\n  $K\\to\u03c0\u03bd\\bar\u03bd$ decays: The rare kaon decays $K\\to\\pi\\nu\\bar{\\nu}$ are strongly suppressed in the\nstandard model and widely regarded as processes in which new phenomena, not\npredicted by the standard model, may be observed. Recognizing such new\nphenomena requires precise standard model prediction for the braching ratio of\n$K\\to\\pi\\nu\\bar{\\nu}$ with controlled uncertainty for both short-distance and\nlong-distance contributions. In this work we demonstrate the feasibility of\nlattice QCD calculation of the long-distance contribution to rare kaon decays\nwith the emphasis on $K^+\\to\\pi^+\\nu\\bar{\\nu}$. Our methodology covers the\ncalculation of both $W$-$W$ and $Z$-exchange diagrams. We discuss the\nestimation of the power-law, finite-volume corrections and two methods to\nconsistently combine the long distance contribution determined by the lattice\nmethods outlined here with the short distance parts that can be reliably\ndetermined using perturbation theory. It is a subsequent work of our first\nmethodology paper on $K\\to\\pi\\ell^+\\ell^-$, where the focus was made on the\n$\\gamma$-exchange diagrams."
    },
    {
        "anchor": "S parameter and parity doubling below the conformal window: Recently the Lattice Strong Dynamics Collaboration reported a reduction of\nthe electroweak S parameter for SU(3) gauge theory with Nf=6 fermions in the\nfundamental representation, compared to scaled-up QCD (arXiv:1009.5967). Here I\nprovide additional details of our calculation. I discuss our use of conserved\nlattice currents; the relation to vector--axial parity doubling; finite-volume\neffects; and the sensitivity of our results to the number of fermion doublets\nwith chiral electroweak couplings. Results presented here include additional\ndata, and do not affect our previously-published conclusions.",
        "positive": "Renormalization of two-dimensional XQCD: Recently, Kaplan proposed an interesting extension of QCD named Extended QCD\nor XQCD with bosonic auxiliary fields [1]. While its partition function is kept\nexactly the same as that of QCD, XQCD naturally contains properties of\nlow-energy hadrons. We apply this extension to the two-dimensional QCD in the\nlarge $N_c$ limit ('t Hooft model) [2]. In this solvable model, it is possible\nto directly examine the hadronic picture of the 2d XQCD and analyze its\nrenormalization group flow to understand how the auxiliary degrees of freedom\nbehave in the low energy region. We confirm that the additional scalar fields\ncan become dynamical acquiring the kinetic term, and its parity-odd part\nbecomes dominant in the low energy region. This renomalization of XQCD provides\nan \"extension\" of the renormalization scheme of QCD, inserting different field\nvariables from those in the original theory, without any changes in physical\nobservables."
    },
    {
        "anchor": "Charm mass effects in the static energy computed in 2+1+1 flavor lattice\n  QCD: We report our analysis for the static energy in (2+1+1)-flavor QCD over a\nwide range of lattice spacings and several quark masses. We obtain results for\nthe static energy out to distances of nearly 1 fm, allowing us to perform a\nsimultaneous determination of the lattice scales $r_2$, $r_1$ and $r_0$ as well\nas the string tension, $\\sigma$. While our results for ${r_0}/{r_1}$ and $r_0$\n$\\sqrt{\\sigma}$ agree with published (2+1)-flavor results, our result for\n${r_1}/{r_2}$ differs significantly from the value obtained in the (2+1)-flavor\ncase, likely due to the effect of the charm quark. We study in detail the\neffect of the charm quark on the static energy by comparing our results on the\nfinest lattices with the previously published (2+1)-flavor QCD results at\nsimilar lattice spacing. The lattice results agree well with the two-loop\nperturbative expression of the static energy incorporating finite charm mass\neffects.",
        "positive": "Undoubled Chiral Fermions on a Lattice: We analyze the dynamics of an $SU_L(2)\\otimes U_R(1)$ chiral theory on the\nlattice with a strong multifermion coupling. It is shown that no spontaneous\nsymmetry breaking occurs; the ``spectator'' fermion $\\psi_R$ is a free mode;\ndoublers are decoupled as massive Dirac fermions consistently with the chiral\nsymmetries. In 1+1 dimension, we show that the right-handed three-fermion state\ndisappears at the threshold and an undoubled left-handed chiral fermion remains\nin the continuum limit."
    },
    {
        "anchor": "Strong isospin breaking in Sp(4) gauge theory: A hidden strongly-interacting sector is a possible candidate for dark matter.\nOne scenario consistent with astrophysical constraints is a QCD-like theory\nwith gauge group Sp(4) and two fundamental non-degenerate fermions. We report\nexploratory investigations of the light spectrum and decay constants for this\ntheory using lattice calculations.",
        "positive": "Moments of nucleon generalized parton distributions from lattice QCD\n  simulations at physical pion mass: We present results for the moments of nucleon isovector vector and axial\ngeneralised parton distribution functions computed within lattice QCD. Three\nensembles of maximally twisted mass clover-improved fermions simulated with a\nphysical value of the pion mass are analyzed. Two of these ensembles are\ngenerated using two degenerate light quarks. A third ensemble is used having,\nin addition to the light quarks, strange and charm quarks in the sea. A careful\nanalysis of the convergence to the ground state is carried out that is shown to\nbe essential for extracting the correct nucleon matrix elements. This allows a\ncontrolled determination of the unpolarised, helicity and tensor second Mellin\nmoments. The vector and axial-vector generalised form factors are also computed\nas a function of the momentum transfer square up to about 1 GeV$^2$. The three\nensembles allow us to check for unquenching effects and to assess lattice\nfinite volume effects."
    },
    {
        "anchor": "Performance of GTX Titan X GPUs and Code Optimization: Recently Nvidia has released a new GPU model: GTX Titan X (TX) in a linage of\nthe Maxwell architecture. We use our conjugate gradient code and\nnon-perturbative renormalization code to measure the performance of TX. The\nresults are compared with those of GTX Titan Black (TB) in a lineage of the\nKepler architecture. We observe a significant gain in the single and double\nprecision calculations much greater than the theoretical expectation.",
        "positive": "The Phase Diagram of 2 flavour QCD with improved Actions: It has been proposed, that the chiral continuum limit of 2-flavour QCD with\nWilson fermions is brought about by a phase in which flavour and parity\nsymmetry are broken spontaneously at finite lattice spacing. At finite\ntemperature this phase should retract from the weak coupling limit to form 5\ncusps. This scenario is studied with tree level Symanzik improved actions for\nboth gauge and fermion fields on lattices of size $8^3\\times 4$ and $12^2\\times\n24\\times 4$."
    },
    {
        "anchor": "New polynomially exact integration rules on U(N) and SU(N): In lattice Quantum Field Theory, we are often presented with integrals over\npolynomials of coefficients of matrices in U(N) or SU(N) with respect to the\nHaar measure. In some physical situations, e.g., in presence of a chemical\npotential, these integrals are numerically very difficult since their\nintegrands are highly oscillatory which manifests itself in form of the sign\nproblem. In these cases, Monte Carlo methods often fail to be adequate,\nrendering such computations practically impossible. We propose a new class of\nintegration rules on U(N) and SU(N) which are derived from polynomially exact\nrules on spheres. We will examine these quadrature rules and their efficiency\nat the example of a 0+1 dimensional QCD for a non-zero quark mass and chemical\npotential. In particular, we will demonstrate the failure of Monte Carlo\nmethods in such applications and that we can obtain polynomially exact,\narbitrary precision results using the new integration rules.",
        "positive": "Continuum interpretation of the dynamical-triangulation formulation of\n  quantum Einstein gravity: In the time-space symmetric version of dynamical triangulation, a\nnon-perturbative version of quantum Einstein gravity, numerical simulations\nwithout matter have shown two phases, with spacetimes that are either crumpled\nor elongated like branched polymers, with strong evidence of a first-order\ntransition between them. These properties have generally been considered\nunphysical. Using previously unpublished numerical results, we give an\ninterpretation in terms of continuum spacetimes that have constant positive and\nnegative curvature, respectively in the 'elongated' and 'crumpled' phase. The\nmagnitude of the positive curvature leads naturally to average spacetimes\nconsisting solely of baby-universes in a branched-polymer structure, whereas\nthe negative curvature accommodates easily a large mother universe, albeit with\na crumpling singularity. Nevertheless, there is evidence for scaling in the\ncrumpled phase, which we compare with the well-known scaling in the elongated\nphase. Using constraint effective-action models we analyze existing numerical\nsusceptibility-data of the phase transition and determine the behavior of the\naverage Regge-curvature. We propose a renormalization of the Regge curvature\nand compare it to the curvature of the above continuum spacetimes, and also to\nthe curvature implied by the Gauss-Bonnet theorem in the continuum. The latter\ninvolves a more benign multiplicative renormalization and suggests that\nsimulations at larger volumes are needed to settle the order of the phase\ntransition."
    },
    {
        "anchor": "Moments of singlet parton densities on the lattice in the Schroedinger\n  Functional scheme: A non perturbative computation of the evolution of singlet parton densities\nwithout gauge--fixing requires a gauge invariant gluon source operator. Within\nthe Schr\\\"odinger Functional scheme (SF), such a source can be defined in terms\nof path ordered products of gauge links, connected to the time boundaries. In\nthis paper we adopt this definition and perform a one loop lattice computation\nof the renormalization constants of the twist--2 operators that correspond to\nthe second moment of singlet parton densities. This calculation fixes the\nconnection between the lattice SF scheme where a non perturbative evaluation of\nthe absolute normalization of singlet parton densities can be made at low\nenergy and the $\\bar{MS}$ scheme where one can extract the experimental values.",
        "positive": "Ginsparg-Wilson relation and lattice Weyl fermions: We demonstrate that in the topologically trivial gauge sector the\nGinsparg-Wilson relation for lattice Dirac operators admits an exactly gauge\ninvariant path integral formulation of the Weyl fermions on a lattice."
    },
    {
        "anchor": "Lattice QCD Study of Transverse-Momentum Dependent Soft Function: In this work, we perform a lattice QCD study of the intrinsic,\nrapidity-independent soft function within the framework of large momentum\neffective theory. The computation is carried out using a gauge ensemble of\n$N_f=2+1+1$ clover-improved twisted mass fermion. After applying an appropriate\nrenormalization procedure and the removal of significant higher-twist\ncontamination, we obtain the intrinsic soft function that is comparable to the\none-loop perturbative result at large external momentum. The determination of\nthe nonperturbative soft function from first principles is crucial to sharpen\nour understanding of the processes with small transverse momentum such as the\nDrell-Yan production and the semi-inclusive deep inelastic scattering.\nAdditionally, we calculate the Collins-Soper evolution kernel using the\nquasi-transverse-momentum-dependent wave function as input.",
        "positive": "Numerical study of staggered quark action on quenched anisotropic\n  lattices: The staggered quark action on anisotropic lattices is studied. We carry out\nnumerical simulations in the quenched approximation at three values of lattice\nspacing ($a_{\\sigma}^{-1}=1-2$ GeV) with the anisotropy $\\xi=\na_{\\sigma}/a_{\\tau}=4$, where $a_{\\sigma}$ and $a_{\\tau}$ are the spatial and\ntemporal lattice spacings, respectively. The bare anisotropy $\\gamma_F$ in the\nquark action is numerically tuned through the ratio of meson masses in the fine\nand coarse directions, and through the dispersion relation of a meson, so that\nthe renormalized fermionic anisotropy coincides with that of the gauge field.\nThe discrepancy between these two calibration schemes provides an estimate of\nthe finite lattice artifact, which is found to be sizable in the range of\ncutoff explored in this work. We also compute the meson masses using\ncorrelators with the wall source at the tuned anisotropy parameter. The flavor\nsymmetry breaking effect smoothly decreases as $\\beta$ increases. The effect of\nuncertainty in $\\gamma_F$ on the meson masses are examined. We also discuss a\nperspective on dynamical simulations."
    },
    {
        "anchor": "Mesonic spectroscopy of Minimal Walking Technicolor: We investigate the structure and the novel emerging features of the mesonic\nnon-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision\nmeasurements in the nonsinglet pseudoscalar and vector channels are compared to\nthe expectations for an IR-conformal field theory and a QCD-like theory. Our\nresults favor a scenario in which MWT is (almost) conformal in the infrared,\nwhile spontaneous chiral symmetry breaking seems less plausible.",
        "positive": "Exotic vector charmonium and its leptonic decay width: We propose a novel type of interpolating field operators, which manifests the\nhybrid-like configuration that the charm quark-antiquark pair recoils against\ngluonic degrees of freedom. A heavy vector charmonium-like state with a mass of\n$4.33(2)\\,{\\rm GeV}$ is disentangled from the conventional charmonium states in\nthe quenched approximation. This state has affinity for the hybrid-like\noperators but couples less to the relevant quark bilinear operator. We also try\nto extract its leptonic decay constant and give a tentative upper limit that it\nis less than one tenth of that of $J/\\psi$, which corresponds to a leptonic\ndecay width about dozens of eV. The connection of this state with $X(4260)$ is\nalso discussed."
    },
    {
        "anchor": "Deconfinement transition and localization of Dirac modes in\n  finite-temperature $\\mathbb{Z}_3$ gauge theory on the lattice: We study the localization properties of the eigenmodes of the staggered Dirac\noperator across the deconfinement transition in finite-temperature\n$\\mathbb{Z}_3$ pure gauge theory on the lattice in 2+1 dimensions. This allows\nfor nontrivial tests of the sea-islands picture of localization, according to\nwhich low modes should localize on favorable Polyakov-loop fluctuations in the\ndeconfined phase of a gauge theory. We observe localized low modes in the\ndeconfined phase of the theory, both in the real Polyakov-loop sector, where\nthey are expected, and in the complex Polyakov-loop sectors, where they are\nnot. Our findings expose the limitations of the standard sea-islands picture,\nand call for its refinement. An improved picture, where spatial hopping terms\nplay a more prominent role, is proposed and found to be in excellent agreement\nwith numerical results.",
        "positive": "Blocking of Dynamical Triangulations with Matter: We use the recently proposed node decimation algorithm for blocking dynamical\ngeometries to investigate a class of models, with central charge greater than\nunity, coupled to 2D gravity. We demonstrate that the blocking preserves the\nfractal structure of the surfaces."
    },
    {
        "anchor": "The \\boldmath$B\\to D^\\ast\\ell\u03bd$ semileptonic decay at nonzero recoil\n  and its implications for $\\ |V_{cb}\\ |$ and $R(D^\\ast)$: We present nearly final results from our analysis of the form factors for\n$B\\to D^\\ast\\ell\\nu$ decay at nonzero recoil. Our analysis includes 15 MILC\nasqtad ensembles with $N_f=2+1$ flavors of sea quarks and lattice spacings\nranging from $a\\approx0.15$ fm down to $0.045$ fm. The valence light quarks\nemploy the asqtad action, whereas the $b$ and $c$ quarks are treated using the\nFermilab action. We discuss the impact that our results will have on $\\\n|V_{cb}\\ |$ and $R(D^\\ast)$.",
        "positive": "Nucleon average quark momentum fraction with $N_\\mathrm{f}=2+1$ Wilson\n  fermions: We report on an analysis of the average quark momentum fraction of the\nnucleon and related quantities using $N_\\mathrm{f}=2+1$ Wilson fermions.\nComputations are performed on four CLS ensembles covering three values of the\nlattice spacing at pion masses down to $M_\\pi \\approx 200\\,\\mathrm{MeV}$.\nSeveral source-sink separations ($\\sim 1.0\\,\\mathrm{fm}$ to $\\sim\n1.4\\,\\mathrm{fm}$) are used to assess the excited-state contamination. To gain\nfurther insight, the generalized pencil-of-functions approach has been\nimplemented to reduce the excited-state contamination in the relevant two- and\nthree-point functions. Preliminary results are shown for the isovector nucleon\ncharges from vector, axial vector and tensor derivative (twist-2) operators."
    },
    {
        "anchor": "Hybrid Quarkonia on Asymmetric Lattices: We report on a study of heavy hybrid states using the NRQCD approach on\ncoarse and asymmetric lattices, where we discard vacuum polarisation effects\nand neglect all spin-correction terms. We find a clear hybrid signal on all our\nlattices ($a_s= 0.15 ... 0.47$ fm). We have studied in detail the lattice\nspacing artefacts, finite volume effects and mass dependence. Within the above\napproximations we predict the hybrid excitation in Charmonium to be 1.323(13)\nGeV above its ground state. The bottomonium hybrid was found to be 1.542(8) GeV\nabove its ground state.",
        "positive": "Light vector meson decay constants and the renormalization factor from a\n  tadpole-improved action: The rho, K* and phi decay constants and the vector current renormalization\nfactor are studied by using an O(a^2) classically-improved, tadpole-improved\naction. Tree-level calculations are used to show how the classical improvement\nof the action, involving next-nearest-neighbour timesteps, is transferred to\nthe matrix elements. Simulations are performed on coarse lattices and compared\nto Wilson results from both coarse and fine lattices. The improved action data\nare found to resemble Wilson data obtained at 1/3 of the lattice spacing, which\nis the same degree of improvement that is seen by comparing the mass spectra."
    },
    {
        "anchor": "The gradient flow in a twisted box: We study the perturbative behavior of the gradient flow in a twisted box. We\napply this information to define a running coupling using the energy density of\nthe flow field. We study the step-scaling function and the size of cutoff\neffects in SU(2) pure gauge theory. We conclude that the twisted gradient flow\nrunning coupling scheme is a valid strategy for step-scaling purposes due to\nthe relatively mild cutoff effects and high precision.",
        "positive": "A Test of The Source Galerkin Method: Some results of the ongoing development of our Source Galerkin (SG)\nnonperturbative approach to numerically solving Quantum Field theories are\npresented. This technique has the potential to be much faster than Monte Carlo\nmethods. SG uses known symmetries and theoretical properties of a theory. In\norder to test this approach, we applied it to phi^4 theory in zero dimensions.\nThis model has been extensively studied and has a known set of exact solutions.\nThis allows us to broaden the understanding of various properties of the SG\nmethod and to develop techniques necessary for the successful application of\nthis method to more sophisticated theories."
    },
    {
        "anchor": "The Thermal Glueball at Finite Temperature in SU(3) Anisotropic Lattice\n  QCD: The thermal glueball is studied at finite temperature by using SU(3)\nanisotropic lattice QCD with beta_{lat}=6.25, the renormalized anisotropy xi =\na_s/a_t = 4 over the lattice of the size 20^3xN_t with various N_t at the\nquenched level. While the narrow peak ansatz leads to the significant polemass\nreduction of about 300 MeV near the critical temperature T_c, Breit-Wigner\nansatz which can take into account the possible appearance of the thermal width\nleads to the significant thermal width broadening of about 300 MeV with a\nmodest reduction of the peak center of about 100 MeV.",
        "positive": "Two topics from lattice NRQCD at non-zero temperature: heavy quark mass\n  dependence and S-wave bottomonium states moving in a thermal bath: Using Non-Relativistic QCD (NRQCD), we study heavy quark mass dependence of\nS-wave and P-wave bottomonium correlators for 0.42Tc <= T <= 2.09Tc and study\nspectral functions of S-wave bottomonium states moving in a thermal bath at\nthese temperatures using Maximum Entropy Method with NRQCD kernel. For the\nstudied momentum range, the energy of moving states shows quadratic\nmomentum-dependence and the width of moving states does not show significant\nchanges as the momentum of bottomonium is increased. Also, we find that in\ncorrelator ratios, the temperature effect is larger than the effect caused by\n20% change in the bottom quark mass."
    },
    {
        "anchor": "Instantons and Monopoles in the Maximally Abelian Gauge: We study the Abelian projection of SU(2) instantons in the Maximally Abelian\ngauge. We find that in this gauge an isolated instanton produces a closed\nmonopole loop within its core and the size of this loop increases with the core\nsize. We show that this result is robust against the introduction of small\nquantum fluctuations. We investigate the effects of neighbouring\n(anti)instantons upon each other and show how overlapping (anti)instantons can\ngenerate larger monopole loops. We find, however, that in fields that are\ntypical of the fully quantised vacuum only some of the large monopole loops\nthat are important for confinement have a topological origin. We comment on\nwhat this may imply for the role of instantons in confinement and chiral\nsymmetry breaking.",
        "positive": "Anomalous fermion number violation and numerical simulations: After discussing the problem of lattice regularization of chiral gauge\ntheories, a simple model for anomalous fermion number violation is formulated\nwhich can be numerically studied with present day technique. Exploratory\nresults of numerical simulations of a two-dimensional U(1) Higgs model are\npresented."
    },
    {
        "anchor": "Super-Instantons and the Reliability of Perturbation Theory in\n  Non-Abelian Models: In dimension $D\\leq 2$ the low temperature behavior of systems enjoying a\ncontinuous symmetry is dominated by super-instantons: classical configurations\nof arbitrarily low energy. Perturbation theory in the background of a\nsuper-instanton produces thermodynamic answers for the invariant Green's\nfunctions that differ from the standard ones, but only in non-Abelian models\nand only starting at $O(1/\\beta^2)$. This effect modifies the $\\beta$-function\nof the $O(N)$ models and persists in the large $N$ limit of the $O(N)$ models.",
        "positive": "One-flavor algorithm for Wilson and domain-wall fermions: We construct positive-definite pseudofermion actions for one fermion flavor\nin lattice field theory, for Wilson and domain-wall fermions respectively. The\npositive definiteness of these actions ensures that they can be simulated with\nthe Hybrid Monte Carlo (HMC) method. For lattice QCD with optimal domain-wall\nquarks, we compare the efficiency of HMC simulations of 2-flavor and\n(1+1)-flavor, and find that the efficiency ratio is about 3:2."
    },
    {
        "anchor": "Newtonian Binding from Lattice Quantum Gravity: We study scalar fields propagating on Euclidean dynamical triangulations\n(EDT). In this work we study the interaction of two scalar particles, and we\nshow that in the appropriate limit we recover an interaction compatible with\nNewton's gravitational potential in four dimensions. Working in the quenched\napproximation, we calculate the binding energy of a two-particle bound state,\nand we study its dependence on the constituent particle mass in the\nnon-relativistic limit. We find a binding energy compatible with what one\nexpects for the ground state energy by solving the Schr\\\"{o}dinger equation for\nNewton's potential. Agreement with this expectation is obtained in the\ninfinite-volume, continuum limit of the lattice calculation, providing\nnon-trivial evidence that EDT is in fact a theory of gravity in four\ndimensions. Furthermore, this result allows us to determine the lattice spacing\nwithin an EDT calculation for the first time, and we find that the various\nlattice spacings are smaller than the Planck length, suggesting that we can\nachieve a separation of scales and that there is no obstacle to taking a\ncontinuum limit. This lends further support to the asymptotic safety scenario\nfor gravity.",
        "positive": "Anomalous dimensions on the lattice: We review methods and results for extracting the anomalous dimensions of\noperators from lattice field theory calculations. The most important\napplication is the anomalous mass dimension in conformal or nearly conformal\ngauge field theories which might be related to dynamical electroweak symmetry\nbreaking. Some discussion of the underlying theory of renormalization and\nmixing of operators is also included."
    },
    {
        "anchor": "Mass effects on the QCD $\u03b2$-function: In this study we present lattice results on the QCD $\\beta$-function in the\npresence of quark masses. The $\\beta$-function is calculated to three loops in\nperturbation theory and for improved lattice actions; it is extracted from the\nrenormalization of the coupling constant $Z_g$. The background field method is\nused to compute $Z_g$, where it is simply related to the background gluon field\nrenormalization constant $Z_A$. We focus on the quark mass effects in the\nbackground gluon propagator; the dependence of the QCD $\\beta$-function on the\nnumber of colors $N_c$, the number of fermionic flavors $N_f$ and the quark\nmasses, is shown explicitly. The perturbative results of the QCD\n$\\beta$-function will be applied to the precise determination of the strong\ncoupling constant, calculated by Monte Carlo simulations removing the mass\neffects from the nonperturbative Green's functions.",
        "positive": "Susceptibility of Monte-Carlo Generated Projected Vortices: We determine the topological susceptibility from center projected vortices\nand demonstrate that the topological properties of the SU(2) Yang-Mills vacuum\ncan be extracted from the vortex content. We eliminate spurious ultraviolet\nfluctuations by two different smoothing procedures. The extracted\nsusceptibility is comparable to that obtained from full field configurations."
    },
    {
        "anchor": "Flavor Twisted Boundary Conditions and the Nucleon Axial Current: With twisted boundary conditions on the quark fields, we study nucleon matrix\nelements of the axial current utilizing twisted heavy baryon chiral\nperturbation theory. One can explore the momentum transfer dependence of the\naxial form factors more easily than by using ordinary lattice quantized momenta\nalone. As examples, we derive expressions for the nucleon axial radius and\npseudoscalar form factor.",
        "positive": "Continuum estimate of the heavy quark momentum diffusion coefficient\n  $\u03ba$: Among quantities playing a central role in the theoretical interpretation of\nheavy ion collision experiments at RHIC and LHC are so-called transport\ncoefficients. Out of those heavy quark diffusion coefficients play an important\nrole e.g. for the analysis of the quenching of jets containing c or b quarks (D\nor B mesons) as observed at RHIC and LHC. We report on a lattice investigation\nof heavy quark momentum diffusion within pure SU(3) plasma above the\ndeconfinement transition with the quarks treated to leading order in the heavy\nmass expansion. We measure the relevant colour-electric Euclidean correlator\nand based on several lattice spacings perform the continuum extrapolation. This\nextends our previous studies progressing towards a removal of lattice artifacts\nand a physical interpretation of the results. We find that the correlation\nfunction clearly exceeds its perturbative counterpart which suggests that at\ntemperatures just above the critical one, non-perturbative interactions felt by\nthe heavy quarks are stronger than within the weak-coupling expansion. Using an\nAnsatz for the spectral function which includes NNLO perturbative contributions\nwe were able to determine, for the first time, a continuum estimate for the\nheavy quark momentum diffusion coefficient."
    },
    {
        "anchor": "CP violation and Kaon weak matrix elements from Lattice QCD: In this short review, I present the recent lattice computations of kaon weak\nmatrix elements relevant to $K \\to \\pi\\pi$ decays and neutral kaon mixing.\nThese matrix elements are key to the theoretical determination of the CP\nviolation parameters $\\epsilon$ and $\\epsilon'$ . Impressive progress have been\nachieved recently, in particular the first realistic computation of\n$\\epsilon'/\\epsilon$ with physical kinematics has been reported in [1]. The\nnovelty is the $\\Delta I = 1/2$ channel, whereas the $\\Delta I = 3/2$\ncontribution is now computed at several values of the lattice spacing and\nextrapolated to the continuum limit. I will also present the status of $B_K$\nand discuss its error budget, with a particular emphasis on the perturbative\nerror. Finally I will review the matrix elements of neutral kaon mixing beyond\nthe standard model and will argue that the discrepancy observed by different\ncollaborations could be explained by the renormalisation procedure of the\nrelevant four-quark operators.",
        "positive": "Implementation of bond weighting method for the Grassmann tensor\n  renormalization group: We demonstrate the efficiency of the bond weighting method for the Grassmann\ntensor renormalization group (TRG). Benchmarking with the two-dimensional\nGross-Neveu model with the Wilson fermion at finite density, we show that the\nbond weighting method improves the accuracy of the original Grassmann TRG. We\nalso provide a sample code of the bond-weighted TRG that can be applied to the\ntwo-dimensional models including fermions on a square lattice."
    },
    {
        "anchor": "Simulations of one-flavor QCD at finite temperature by RHMC: We simulate one-flavor QCD with standard Wilson fermions at finite\ntemperature by the rational hybrid Monte Carlo algorithm. In the heavy quark\nregion when we decrease the quark mass there is an endpoint which terminates\nthe first order phase transition. We try to locate it by calculating the Binder\ncumulant of the Polyakov loop norm. We estimate the end-point to be kappa_c\n\\sim 0.07-0.08.",
        "positive": "In-medium modifications of open and hidden strange-charm mesons from\n  spatial correlation functions: We calculate spatial correlation functions of in-medium mesons consisting of\nstrange--anti-strange, strange--anti-charm and charm--anti-charm quarks in\n(2+1)-flavor lattice QCD using the highly improved staggered quark action. A\ncomparative study of the in-medium modifications of mesons with different\nflavor contents is performed. We observe significant in-medium modifications\nfor the $\\phi$ and $D_s$ meson channels already at temperatures around the\nchiral crossover region. On the other hand, for the $J/\\psi$ and $\\eta_c$ meson\nchannels in-medium modifications remain relatively small around the chiral\ncrossover region and become significant only above 1.3 times the chiral\ncrossover temperature."
    },
    {
        "anchor": "A Phenomenological Treatment of Chiral Symmetry Restoration and\n  Deconfinement: A phenomenological expression for the thermodynamic potential of gluons and\nquarks is constructed which incorporates the features of deconfinement and\nchiral symmetry restoration known from lattice simulations. The thermodynamic\npotential is a function of the Polyakov loop and chiral condensate expectation\nvalues. The gluonic sector uses a successful model for pure (SU(N_c)) gauge\ntheories in which the Polyakov loop eigenvalues are the fundamental order\nparameters for deconfinement. The quark sector is given by a Nambu-Jona-Lasinio\nmodel in which a constant background (A_0) field couples the chiral condensate\nto the Polyakov loop. We consider the case of (N_f = 2) in detail. For two\nmassless quarks, we find a second order chiral phase transition. Confinement\neffects push the transition to higher temperatures, but the entropy associated\nwith the gluonic sector acts in the opposite direction. For light mass quarks,\nonly a rapid crossover occurs. For sufficiently heavy quarks, a first order\ndeconfinement transition emerges. This simplest model has one adjustable\nparameter, which can be set from the chiral transition temperature for light\nquarks. It predicts all thermodynamic quantities as well as the behavior of the\nchiral condensate and the Polyakov loop over a wide range of temperatures.",
        "positive": "Colour flux-tubes in static Pentaquark and Tetraquark systems: The colour fields created by the static tetraquark and pentaquark systems are\ncomputed in quenched SU(3) lattice QCD, with gauge invariant lattice operators,\nin a 24^3 x 48 lattice at beta=6.2. We generate our quenched configurations\nwith GPUs, and detail the respective benchmanrks in different SU(N) groups.\nWhile at smaller distances the coulomb potential is expected to dominate, at\nlarger distances it is expected that fundamental flux tubes, similar to the\nflux-tube between a quark and an antiquark, emerge and confine the quarks. In\norder to minimize the potential the fundamental flux tubes should connect at\n120o angles. We compute the square of the colour fields utilizing plaquettes,\nand locate the static sources with generalized Wilson loops and with APE\nsmearing. The tetraquark system is well described by a double-Y-shaped\nflux-tube, with two Steiner points, but when quark-antiquark pairs are close\nenough the two junctions collapse and we have an X-shaped flux-tube, with one\nSteiner point. The pentaquark system is well described by a three-Y-shaped\nflux-tube where the three flux the junctions are Steiner points."
    },
    {
        "anchor": "SU(3) Thermodynamics on Small Lattices: The free energy density of the SU(3) gauge theory at temperatures T/T_c =\n4/3, 3/2 and 2 is calculated on lattices with temporal extent as small as N_t =\n2, 3 and spatial extent N_s = 4 N_t using parametrized fixed point actions.\nAlthough cut-off effects are seen, they are hugely suppressed with respect to\nWilson and Symanzik-improved actions and at N_t = 3 there is already a good\nagreement with the continuum limit as extrapolated from the results with the\nWilson action at N_t = 6 and 8.",
        "positive": "QCD with chemical potential on S^1 x S^3: In this proceedings we summarize our calculation of the phase diagram of QCD\nat non-zero temperature and chemical potential on S^1 x S^3 from one-loop\nperturbation theory [1], which is valid in the limit R << 1/Lambda, where R is\nthe radius of S^3. We calculate several observables including the Polyakov\nlines and the quark number, for large number of colors N and large number of\nquark flavors Nf, on S^1 x S^3, and compare with results for the same system\nwith N = 3, and with results for N=2 lattice QCD. For N > 2 the action is\ncomplex and the dominant contributions to the path integral occur in the space\nof complexified gauge field configurations. This results in the expectation\nvalues of the eigenvalues of the Polyakov line lying off the unit circle and\nout in the complex plane. This is an important issue for the lattice, and also\nfor the calculation on S^1 x S^3 in the large N limit where we obtain\nanalytical results using the saddle point approximation. It is thus necessary\nto adapt available techniques to locate the stationary solutions in the\ncomplexified gauge field configuration space."
    },
    {
        "anchor": "Topology of the SU(2) vacuum: a lattice study using improved cooling: We study the topological structure of the SU(2) vacuum at zero temperature:\ntopological susceptibility, size, shape and distance distributions of the\ninstantons. We use a cooling algorithm based on an improved action with scale\ninvariant instanton solutions. This algorithm needs no monitoring or\ncalibration, has an inherent cut off for dislocations and leaves unchanged\ninstantons at physical scales. The physical relevance of our results is checked\nby studying the scaling and finite volume dependence. We obtain a\nsusceptibility of (200(15) MeV)^4. The instanton size distribution is peaked\naround 0.43fm, and the distance distribution indicates a homogeneous, random\nspatial structure.",
        "positive": "Convergent Perturbation Theory for the lattice $\u03c6^4$-model: The standard lattice perturbation theory leads to the asymptotic series\nbecause of the incorrect interchange of the summation and integration. However,\nchanging the initial approximation of the perturbation theory, one can generate\nthe convergent series. We study the lattice $\\phi^4$-model and compare the\noperator $\\langle\\phi_n^2\\rangle$ calculated using the convergent series and\nobtained by Monte Carlo simulations."
    },
    {
        "anchor": "Capillary Wave Approach to Order-Order Fluid Interfaces in the 3D\n  Three-State Potts Model: The physics of fluid interfaces between domains of different magnetization in\nthe ordered phase of the 3D three-state Potts model is studied by means of a\nMonte Carlo simulation. It is shown that finite--size effects in the interface\nfree energy are well described by the capillary wave model at two loop order,\nsupporting the idea of the universality of this description of fluid interfaces\nin 3D statistical models.",
        "positive": "Lattice QCD at finite isospin density at zero and finite temperature: We simulate lattice QCD with dynamical $u$ and $d$ quarks at finite chemical\npotential, $\\mu_I$, for the third component of isospin ($I_3$), at both zero\nand at finite temperature. At zero temperature there is some $\\mu_I$, $\\mu_c$\nsay, above which $I_3$ and parity are spontaneously broken by a charged pion\ncondensate. This is in qualitative agreement with the prediction of effective\n(chiral) Lagrangians which also predict $\\mu_c=m_\\pi$. This transition appears\nto be second order, with scaling properties consistent with the mean-field\npredictions of such effective Lagrangian models. We have also studied the\nrestoration of $I_3$ symmetry at high temperature for $\\mu_I > \\mu_c$. For\n$\\mu_I$ sufficiently large, this finite temperature phase transition appears to\nbe first order. As $\\mu_I$ is decreased it becomes second order connecting\ncontinuously with the zero temperature transition."
    },
    {
        "anchor": "Excited-state contribution to the axial-vector and pseudo-scalar\n  correlators with two extra pions: We study multi-particle state contributions to the QCD two-point functions of\nthe axial-vector and pseudo-scalar quark bilinears in a finite spatial volume.\nFor sufficiently small quark masses one expects three-meson states with two\nadditional pions at rest to have the lowest total energy after the ground\nstate. We calculate this three-meson state contribution using chiral\nperturbation theory. We find it to be strongly suppressed and too small to be\nseen in present-day lattice simulations.",
        "positive": "Remarks on domain-wall Fermions: Domain-wall Fermions represent a recent lattice approach to chiral symmetry\nthat is receiving considerable attention. The method is presented in a somewhat\nunconventional manner, in terms of a ladder molecule subjected to a magnetic\nfield. Speculations are made on extending the formalism to multiple species."
    },
    {
        "anchor": "Locality with staggered fermions: We address the locality problem arising in simulations, which take the square\nroot of the staggered fermion determinant as a Boltzmann weight to reduce the\nnumber of dynamical quark tastes. A definition of such a theory necessitates an\nunderlying local fermion operator with the same determinant and the\ncorresponding Green's functions to establish causality and unitarity. We\nillustrate this point by studying analytically and numerically the square root\nof the staggered fermion operator. Although it has the correct weight, this\noperator is non-local in the continuum limit. Our work serves as a warning that\nfundamental properties of field theories might be violated when employing\nblindly the square root trick. The question, whether a local operator\nreproducing the square root of the staggered fermion determinant exists, is\nleft open.",
        "positive": "Overview of the QCD phase diagram -- Recent progress from the lattice: In recent years there has been much progress on the investigation of the QCD\nphase diagram with lattice QCD simulations. In this review I focus on the\ndevelopments in the last two years. Especially the addition of external\ninfluences or new parameter ranges yield an increasing number of interesting\nresults. I discuss the progress for small, finite densities from both\nanalytical continuation and Complex Langevin simulations, for heavy quark bound\nstates (quarkonium), the dependence on the quark masses (Columbia plot) and the\ninfluence of a magnetic field. Many of these conditions are relevant for the\nunderstanding of both the QCD transition in the early universe and heavy ion\ncollision experiments which are conducted for example at the LHC and RHIC."
    },
    {
        "anchor": "Absence of Physical Walls in Hot Gauge Theories: This paper shows that there are no {\\em physical} walls in the deconfined,\nhigh-temperature phase of $Z(2)$ lattice gauge theory. In a Hamiltonian\nformulation, the interface in the Wilson lines is not physical. The line\ninterface and its energy are interpreted in terms of physical variables. They\nare associated with a difference between two partition functions. One includes\nonly the configurations with even flux across the interface. The other is\nrestricted to odd flux. Also, with matter present, there is no physical\nmetastable state. However, the free energy is lowered by the matter. This\neffect is described in terms of physical variables.",
        "positive": "Low-lying Eigenvalues of the QCD Dirac Operator at Finite Temperature: We compute the low-lying spectrum of the staggered Dirac operator above and\nbelow the finite temperature phase transition in both quenched QCD and in\ndynamical four flavor QCD. In both cases we find, in the high temperature\nphase, a density with close to square root behavior, $\\rho(\\lambda) \\sim\n(\\lambda-\\lambda_0)^{1/2}$. In the quenched simulations we find, in addition, a\nvolume independent tail of small eigenvalues extending down to zero. In the\ndynamical simulations we also find a tail, decreasing with decreasing mass, at\nthe small end of the spectrum. However, the tail falls off quite quickly and\ndoes not seem to extend to zero at these couplings. We find that the\ndistribution of the smallest Dirac operator eigenvalues provides an efficient\nobservable for an accurate determination of the location of the chiral phase\ntransition, as first suggested by Jackson and Verbaarschot."
    },
    {
        "anchor": "A note on the exact lattice chiral symmetry in the overlap formalism: Using the grassman-number-integral representation of the vacuum overlap\nformula, it is shown that the symmetry of the auxiliary quantum fermion system\nin the overlap formalism induces exact chiral symmetry of the action of the\ntype given by Luscher under the chiral transformation $\\delta \\psi_n =\n\\gamma_5(1-a D)\\psi_n$ and $ \\delta \\bar \\psi_n = \\bar \\psi_n \\gamma_5$. With\nthis relation, we consider the connection between the covariant form of the\nanomaly discussed in the context of the overlap formula and the axial anomaly\nassociated to the exact chiral symmetry in the action formalism. The covariant\ngauge current in the overlap formalism is translated to the action formalism\nand its explicit expression is obtained.",
        "positive": "Light Quark Masses with an O(a)-Improved Action: We present the recent Fermilab calculations of the masses of the light\nquarks, using tadpole-improved Sheikholeslami-Wohlert (SW) quarks. Various\nsources of systematic errors are studied. Our final result for the average\nlight quark mass in the quenched approximation evaluated in the $\\bar{MS}$\nscheme is $\\bar{m}_q(\\mu=2 GeV;n_f=0)= (m_u+m_d)/2=3.6 \\pm 0.6 MeV$."
    },
    {
        "anchor": "Effect of r averaging on Chiral Anomaly in Lattice QCD with Wilson\n  Fermion: Finite volume and cutoff effects: We demonstrate the effectiveness of averaging over the Wilson parameter r\n(which has been proposed earlier) in removing the cutoff effects of naive\nWilson fermions in both the anomaly term and the pseudoscalar density term in\nthe flavor singlet axial Ward identity at O(g^2) involving slowly varying\nbackground gauge fields. We show that it is the physical fermion contribution\nwhich is largely influenced by the r averaging. We have studied the possible\ninterplay between finite size and cutoff effects by investigating in detail\nnaive, O(a) improved and OStm Wilson fermion cases for a range of volumes and\nlattice fermion mass (am). For naive Wilson fermions r averaging is shown to\nremove the effects of the interplay. We have shown that for the pseudoscalar\ndensity term to O (g^2) the lattice result differs from the continuum result by\nexhibiting considerable am dependence which appears to be a manifestation of\ncutoff effects with naive Wilson fermion. The pseudoscalar density term to\nO(g^2) is shown to be almost independent of am when r-averaging is performed.",
        "positive": "The Kaon $B$-parameter with Wilson Fermions: We calculate the kaon $B$-parameter in quenched lattice QCD at $\\beta=6.0$\nusing Wilson fermions at $\\kappa=0.154$ and $0.155$. We use two kinds of\nnon-local (``smeared'') sources for quark propagators to calculate the matrix\nelements between states of definite momentum. The use of smeared sources yields\nresults with much smaller errors than obtained in previous calculations with\nWilson fermions. By combining results for $\\vec p =(0,0,0)$ and $\\vec p\n=(0,0,1)$, we show that one can carry out the non-perturbative subtraction\nnecessary to remove the dominant lattice artifacts induced by the chiral\nsymmetry breaking term in the Wilson action. Our final results are in good\nagreement with those obtained using staggered fermions. We also present results\nfor $B$-parameters of the $\\Delta I = 3/2$ part of the electromagnetic penguin\noperators, and preliminary results for \\bk\\ in the presence of two flavors of\ndynamical quarks."
    },
    {
        "anchor": "Singlets in gauge theories with fundamental matter: We provide the first determination of the mass of the lightest flavor-singlet\npseudoscalar and scalar bound states (mesons), in the $\\rm{Sp}(4)$ Yang-Mills\ntheory coupled to two flavors of fundamental fermions, using lattice methods.\nThis theory has applications both to composite Higgs and strongly-interacting\ndark matter scenarios. We find the singlets to have masses comparable to those\nof the light flavored states, which might have important implications for\nphenomenological models. We focus on regions of parameter space corresponding\nto a moderately heavy mass regime for the fermions. We compare the spectra we\ncomputed to existing and new results for $\\rm{SU}(2)$ and $\\rm{SU}(3)$\ntheories, uncovering an intriguing degree of commonality. As a by-product, in\norder to perform the aforementioned measurements, we implemented and tested, in\nthe context of symplectic lattice gauge theories, several strategies for the\ntreatment of disconnected-diagram contributions to two-point correlation\nfunctions. These technical advances set the stage for future studies of the\nsinglet sector in broader portions of parameter space of this and other lattice\ntheories with a symplectic gauge group.",
        "positive": "Understanding stochastic perturbation theory: toy models and statistical\n  analysis: The numerical stochastic perturbation method based on Parisi-Wu quantisation\nis applied to a suite of simple models to test its validity at high orders.\nLarge deviations from normal distribution for the basic estimators are\nsystematically found in all cases (``Pepe effect''). As a consequence one\nshould be very careful in estimating statistical errors. We present some\nresults obtained on Weingarten's ``pathological'' model where reliable results\ncan be obtained by an application of the bootstrap method. We also present some\nevidence that in the far less trivial application to Lattice Gauge Theory a\nsimilar problem should not arise at moderately high loops (up to\nO(\\alpha^{10}))."
    },
    {
        "anchor": "Consistency of hadronic vacuum polarization between lattice QCD and the\n  R-ratio: There are emerging tensions for theory results of the hadronic vacuum\npolarization contribution to the muon anomalous magnetic moment both within\nrecent lattice QCD calculations and between some lattice QCD calculations and\nR-ratio results. In this paper we work towards scrutinizing critical aspects of\nthese calculations. We focus in particular on a precise calculation of\nEuclidean position-space windows defined by RBC/UKQCD that are ideal quantities\nfor cross-checks within the lattice community and with R-ratio results. We\nperform a lattice QCD calculation using physical up, down, strange, and charm\nsea quark gauge ensembles generated in the staggered formalism by the MILC\ncollaboration. We study the continuum limit using inverse lattice spacings from\n$a^{-1}\\approx 1.6$ GeV to $3.5$ GeV, identical to recent studies by\nFNAL/HPQCD/MILC and Aubin et al. and similar to the recent study of BMW. Our\ncalculation exhibits a tension for the particularly interesting window result\nof $a_\\mu^{\\rm ud, conn.,isospin, W}$ from $0.4$ fm to $1.0$ fm with previous\nresults obtained with a different discretization of the vector current on the\nsame gauge configurations. Our results may indicate a difficulty related to\nestimating uncertainties of the continuum extrapolation that deserves further\nattention. In this work we also provide results for $a_\\mu^{\\rm\nud,conn.,isospin}$, $a_\\mu^{\\rm s,conn.,isospin}$, $a_\\mu^{\\rm SIB,conn.}$ for\nthe total contribution and a large set of windows. For the total contribution,\nwe find $a_\\mu^{\\rm HVP~LO}=714(27)(13) 10^{-10}$, $a_\\mu^{\\rm\nud,conn.,isospin}=657(26)(12) 10^{-10}$, $a_\\mu^{\\rm\ns,conn.,isospin}=52.83(22)(65) 10^{-10}$, and $a_\\mu^{\\rm\nSIB,conn.}=9.0(0.8)(1.2) 10^{-10}$, where the first uncertainty is statistical\nand the second systematic. We also comment on finite-volume corrections for the\nstrong-isospin-breaking corrections.",
        "positive": "Entanglement generation in $(1+1)D$ QED scattering processes: We study real-time meson-meson scattering processes in $(1+1)$-dimensional\nQED by means of Tensor Networks. We prepare initial meson wave packets with\ngiven momentum and position introducing an approximation based on the free\nfermions model. Then, we compute the dynamics of two initially separated\ncolliding mesons, observing a rich phenomenology as the interaction strength\nand the initial states are varied in the weak and intermediate coupling\nregimes. Finally, we consider elastic collisions and measure some scattering\namplitudes as well as the entanglement generated by the process. Remarkably, we\nidentify two different regimes for the asymptotic entanglement between the\noutgoing mesons: it is perturbatively small below a threshold coupling, past\nwhich its growth as a function of the coupling abruptly accelerates."
    },
    {
        "anchor": "$SU(2)$ Gauge Theory with Two Fundamental Flavours: Scalar and\n  Pseudoscalar Spectrum: We investigate the scalar and pseudoscalar spectrum of the $SU(2)$ gauge\ntheory with $N_f=2$ flavours of fermions in the fundamental representation\nusing non perturbative lattice simulations. We provide first benchmark\nestimates of the mass of the lightest $0(0^{+})$ ($\\sigma$), $0(0^{-})$\n($\\eta'$) and $1(0^+)$ ($a_0$) states, including estimates of the relevant\ndisconnected contributions. We find $m_{a_0}/F_{\\rm{PS}}= 16.7(4.9)$,\n$m_\\sigma/F_{\\rm{PS}}=19.2(10.8)$ and $m_{\\eta'}/F_{\\rm{PS}} = 12.8(4.7)$.\nThese values for the masses of light scalar states provide crucial information\nfor composite extensions of the Standard Model from the unified Fundamental\nComposi te Higgs-Technicolor theory \\cite{Cacciapaglia:2014uja} to models of\ncomposite dark matter.",
        "positive": "Topological susceptibility in full QCD: lattice results versus the\n  prediction from the QCD partition function with granularity: Recent lattice data from CP-PACS, UKQCD, SESAM/TXL and the Pisa group\nregarding the quark mass dependence of the topological susceptibility in\n2-flavour QCD are compared to each other and to theoretical expectations. The\nlatter get specified by referring to the QCD finite-volume partition function\nwith ``granularity'' which accounts for the entropy brought by instantons and\nanti-instantons. The chiral condensate in $N_f=2$ QCD, if determined by this\nmethod, turns out surprisingly large."
    },
    {
        "anchor": "Approximate forms of the density of states: We compare MC calculations of the density of states in SU(2) pure gauge\ntheory with the weak and strong coupling expansions. Surprisingly, the range of\nvalidity of the two approximations overlap significantly, however the large\norder behavior of both expansions appear to be similar to the corresponding\nexpansions of the plaquette. We discuss the implications for the calculation of\nthe Fisher's zeros of the partition function.",
        "positive": "Recent progress in calculation of $B_K$ using staggered fermions: We report on recent progress in the calculation of $B_K$ using HYP-smeared\nimproved staggered fermions on the MILC asqtad lattices. We have added\nmeasurements on fine ($a\\sim 0.09 $fm) and superfine ($a\\sim 0.06 $fm)\nensembles at different values of the light sea quark mass ($a m_\\ell$), as well\nas increased the statistics on some other ensembles. We find that the results\non the fine lattices show a significantly stronger $am_\\ell$ dependence than\nthose on the superfine and coarse ($a\\sim 0.12 $fm) lattices. We discuss\ndifferent methods for accounting for these new results when doing the $a\nm_\\ell$ and continuum extrapolations."
    },
    {
        "anchor": "How to calculate the bubble nucleation rate in first order transitions\n  non-perturbatively: We present a new method for calculating the bubble nucleation rate in first\norder phase transitions non-perturbatively on the lattice. The method takes\ninto account all fluctuations and the full dynamical pre-factor. We also\npresent results from applying it to the cubic anisotropy model, which has a\nradiatively induced, strongly first order phase transition.",
        "positive": "Heavy quark scaling of $B\\to\u03c0\\ell\u03bd$ form factors with M\u00f6bius\n  domain wall fermions: We report on the progress of our calculation of form factors for the\nexclusive semileptonic decay of $B$ mesons to pions on $2+1$ flavour lattices\nwith spacings from $0.080~\\mathrm{fm}$ down to $0.044~\\mathrm{fm}$. Using the\nM\\\"{o}bius domain wall fermion action for all quarks, we simulate pions with\nmasses down to $230~\\mathrm{MeV}$ and extrapolate to the physical bottom quark\nmass by utilizing a range of heavy quark masses up to $2.44$ times the mass of\nthe charm quark. We discuss the dependence on the pion mass, heavy quark mass\nand lattice spacing in our form factors results."
    },
    {
        "anchor": "CORE and the Haldane Conjecture: The Contractor Renormalization group formalism (CORE) is a real-space\nrenormalization group method which is the Hamiltonian analogue of the Wilson\nexact renormalization group equations. In an earlier paper\\cite{QGAF} I showed\nthat the Contractor Renormalization group (CORE) method could be used to map a\ntheory of free quarks, and quarks interacting with gluons, into a generalized\nfrustrated Heisenberg antiferromagnet (HAF) and proposed using CORE methods to\nstudy these theories. Since generalizations of HAF's exhibit all sorts of\nsubtle behavior which, from a continuum point of view, are related to\ntopological properties of the theory, it is important to know that CORE can be\nused to extract this physics. In this paper I show that despite the folklore\nwhich asserts that all real-space renormalization group schemes are necessarily\ninaccurate, simple Contractor Renormalization group (CORE) computations can\ngive highly accurate results even if one only keeps a small number of states\nper block and a few terms in the cluster expansion. In addition I argue that\neven very simple CORE computations give a much better qualitative understanding\nof the physics than naive renormalization group methods. In particular I show\nthat the simplest CORE computation yields a first principles understanding of\nhow the famous Haldane conjecture works for the case of the spin-1/2 and spin-1\nHAF.",
        "positive": "Simulations of ${\\cal N}=2$ super Yang-Mills theory in two dimensions: We present results from lattice simulations of ${\\cal N}=2$ super Yang-Mills\ntheory in two dimensions. The lattice formulation we use was developed in\n\\cite{2dpaper} and retains both gauge invariance and an exact (twisted)\nsupersymmetry for any lattice spacing. Results for both U(2) and SU(2) gauge\ngroups are given. We focus on supersymmetric Ward identities, the phase of the\nPfaffian resulting from integration over the Grassmann fields and the nature of\nthe quantum moduli space."
    },
    {
        "anchor": "Quantum Operator Design for Lattice Baryon Spectroscopy: A previously-proposed method of constructing spatially-extended\ngauge-invariant three-quark operators for use in Monte Carlo lattice QCD\ncalculations is tested, and a methodology for using these operators to extract\nthe energies of a large number of baryon states is developed. This work is part\nof a long-term project undertaken by the Lattice Hadron Physics Collaboration\nto carry out a first-principles calculation of the low-lying spectrum of QCD.\n  These techniques are then applied in the construction of nucleon operators.\nCorrelation matrix elements between these operators are estimated using 200\nconfigurations on a $12^3 \\times 48$ anisotropic lattice in the quenched\napproximation with unphysically heavy u, d quark masses (the pion mass is\napproximately 700 MeV). After a change of basis operators using a variational\nmethod is applied, the energies of up to eight states are extracted in each\nsymmetry channel.\n  Although comparison with experiment is not justified, the pattern of levels\nobtained qualitatively agrees with the observed spectrum. A comparison with\nquark model predictions is also made; the quark model predicts more low-lying\neven-parity states than this study yields, but both the quark model and this\nstudy predict more odd-parity states near 2 GeV than currently observed in\nexperiments.",
        "positive": "Sigma terms of the baryon octet in $N_\\mathrm{f} = 2+1$ QCD with Wilson\n  quarks: A lot of progress has been made in the direct determination of nucleon sigma\nterms. Using similar methods, we consider the sigma terms of the other octet\nbaryons as well. These are determined on CLS gauge field ensembles employing\nthe L\\\"uscher-Weisz gluon action and the Sheikholeslami-Wohlert fermion action\nwith $N_\\mathrm{f} = 2 + 1$. The ensembles have pion masses ranging from\n${410}\\,\\mathrm{MeV}$ down to the physical value and lattice spacings covering\na range between ${0.098}\\,\\mathrm{fm}$ and ${0.039}\\,\\mathrm{fm}$. We present\nsome preliminary results for the pion and strange sigma terms and compare to\nindirect determinations. To do so, we discuss multi-state fits to tackle the\nwell-known problem of excited state contamination comparing the ratio and\nsummation methods also including priors."
    },
    {
        "anchor": "Study of the Decoupling of Heavy Fermions in a Z_2 Scalar-Fermion Model: According to one-loop perturbation theory, fermions whose masses are totally\ngenerated from Yukawa couplings do not decouple in the heavy mass limit. We\ninvestigate this issue nonperturbatively in a 4-dimensional $Z_2$\nscalar-fermion model with staggered fermions. Our data at intermediate and\nstronger Yukawa couplings on $8^4$ and $12^4$ lattices suggest the\nnondecoupling of heavy fermions as predicted from one-loop calculation.\nHowever, at the strongest Yukawa coupling where a possible multi-critical point\nmay come into play, we cannot be conclusive.",
        "positive": "Chiral Perturbation Theory for All-Staggered Heavy-Light Mesons: In highly improved staggered quark (HISQ) simulations by the HPQCD, MILC, and\nFermilab Lattice collaborations, both the light quarks and the charm quark are\nstaggered. We extend chiral perturbation theory for staggered quarks to include\nsuch all-staggered heavy-light mesons. We assume that the heavy quark action is\nsufficiently improved that we may take $a m_Q <<1$ (where $m_Q$ is the heavy\nquark mass), but also that $m_Q>>\\Lambda_{QCD}$ so that a continuum heavy quark\nexpansion is appropriate. We develop this effective chiral theory through\nnext-to-leading order, and use it to study the pattern of taste splittings in\nthe heavy-light meson and to compute the leptonic decay constant of the\nheavy-light meson to one-loop in the chiral expansion."
    },
    {
        "anchor": "Lattice QCD Studies of the Leading Order Hadronic Contribution to the\n  Muon $g-2$: The anomalous magnetic moment of the muon, $g_\\mu-2$, is one of the most\npromising observables to identify hints for physics beyond the Standard Model.\nQCD contributions are currently responsible for the largest fraction of the\noverall theoretical uncertainty in $g_\\mu-2$. The possibility to determine\nthese hadronic contributions from first principles through lattice QCD\ncalculations has triggered a number of recent studies. Recent proposals to\nimprove the accuracy of lattice determinations are reported. We present an\nupdate of our studies of the leading-order hadronic contribution to $g_\\mu-2$\nwith improved Wilson fermions.",
        "positive": "Renormalization of two-loop diagrams in scalar lattice field theory: We present a method to calculate to very high precision the coefficients of\nthe divergences occuring in two-loop diagrams for a massive scalar field on the\nlattice. The approach is based on coordinate space techniques and extensive use\nof the precisely known Green's function."
    },
    {
        "anchor": "Overlap/Domain-wall reweighting: We investigate the eigenvalues of nearly chiral lattice Dirac operators\nconstructed with five-dimensional implementations. Allowing small violation of\nthe Ginsparg-Wilson relation, the HMC simulation is made much faster while the\neigenvalues are not significantly affected. We discuss the possibility of\nreweighting the gauge configurations generated with domain-wall fermions to\nthose of exactly chiral lattice fermions.",
        "positive": "Non-perturbative renormalization constants on the lattice from flavour\n  non-singlet Ward identities: By imposing axial and vector Ward identities for flavour-non-singlet\ncurrents, we estimate in the quenched approximation the non-perturbative values\nof combinations of improvement coefficients, which appear in the expansion\naround the massless case of the renormalization constants of axial,\npseudoscalar, vector, scalar non-singlet currents and of the renormalized mass.\n  These coefficients are relevant for the completion of the improvement\nprogramme to O(a) of such operators.\n  The simulations are performed with a clover Wilson action non-perturbatively\nimproved."
    },
    {
        "anchor": "Ergodic Properties of Classical SU(2) Lattice Gauge Theory: We investigate the relationship between the Lyapunov exponents of periodic\ntrajectories, the average and fluctuations of Lyapunov exponents of ergodic\ntrajectories, and the ergodic autocorrelation time for the two-dimensional\nhyperbola billiard. We then study the fluctuation properties of the ergodic\nLyapunov spectrum of classical SU(2) gauge theory on a lattice. Our results are\nconsistent with the notion that this system is globally hyperbolic. Among the\nmany powerful theorems applicable to such systems, we discuss one relating to\nthe fluctuations in the entropy growth rate.",
        "positive": "Phase structure of QC2D at high temperature and density: We study two-color QCD with two flavors of Wilson fermion as a function of\nquark chemical potential mu and temperature T. We find evidence of a superfluid\nphase at intermediate mu and low T where the quark number density and diquark\ncondensate are both very well described by a Fermi sphere of nearly-free quarks\ndisrupted by a BCS condensate. This gives way to a region of deconfined quark\nmatter at higher T and mu, with the deconfinement temperature decreasing only\nvery slowly with increasing chemical potential. We find that heavy quarkonium\nbound states persist in the S-wave channels at all T and mu, with an energy\nreflecting the phase structure. P-wave states appear not to survive in the\nquarkyonic region."
    },
    {
        "anchor": "Strings and Aharonov-Bohm Effect in Abelian Higgs Model: We investigate numerically the properties of the Abrikosov-Nielsen-Olesen\nstrings in 4D abelian Higgs model. The fractal dimension D_f of the vortex\nstrings was found to be large in the Coulomb phase and it is close to 2 in the\nHiggs phase. We also show that the Wilson loop for non-integer charges is\ncorrelated with the linking number of the vortex string world sheets and the\ntest particle world trajectory. We find that this topological (Aharonov-Bohm)\ninteraction gives the main contribution to the Wilson loop quantum average for\nnon-integer test charges in the vicinity of the Coulomb-Higgs phase transition.",
        "positive": "Clock model interpolation and symmetry breaking in O(2) models: The $q$-state clock model is a classical spin model that corresponds to the\nIsing model when $q=2$ and to the $XY$ model when $q\\to\\infty$. The integer-$q$\nclock model has been studied extensively and has been shown to have a single\nphase transition when $q=2$,$3$,$4$ and two phase transitions when $q>4$.We\ndefine an extended $q$-state clock model that reduces to the ordinary $q$-state\nclock model when $q$ is an integer and otherwise is a continuous interpolation\nof the clock model to noninteger $q$. We investigate this class of clock models\nin 2D using Monte Carlo (MC) and tensor renormalization group (TRG) methods,\nand we find that the model with noninteger $q$ has a crossover and a\nsecond-order phase transition. We also define an extended-$O(2)$ model (with a\nparameter $\\gamma$) that reduces to the $XY$ model when $\\gamma=0$ and to the\nextended $q$-state clock model when $\\gamma\\to\\infty$, and we begin to outline\nthe phase diagram of this model. These models with noninteger $q$ serve as a\ntestbed to study symmetry breaking in situations corresponding to quantum\nsimulators where experimental parameters can be tuned continuously."
    },
    {
        "anchor": "Hot QCD and warm dark matter: One of the possible explanations for the dark matter needed in the standard\ncosmological model is so-called warm dark matter, in the form of right-handed\n(\"sterile\") neutrinos with a mass in the keV range. I describe how various\nproperties of QCD at temperatures of a few hundred MeV play an important role\nin the theoretical computations that are needed for consolidating or falsifying\nthis scenario. In particular the points where lattice QCD could help are\nunderlined.",
        "positive": "The electromagnetic form factors of the Omega in lattice QCD: We present results on the Omega baryon electromagnetic form factors using\n$N_f=2+1$ domain-wall fermion configurations for three pion masses in the range\nof about 350 to 300 MeV. We compare results obtained using domain wall fermions\nwith those of a mixed-action (hybrid) approach, which combine domain wall\nvalence quarks on staggered sea quarks, for a pion mass of about 350 MeV. We\npay particular attention in the evaluation of the subdominant electric\nquadrupole form factor to sufficient accuracy to exclude a zero value, by\nconstructing a sequential source that isolates it from the dominant form\nfactors. The $\\Omega^-$ magnetic moment, $\\mu_{\\Omega^{-}}$, the electric\ncharge and magnetic radius, $\\langle r^{2}_{E0/M1} \\rangle$, are extracted for\nthese pion masses. The electric quadrupole moment is determined for the first\ntime using dynamical quarks."
    },
    {
        "anchor": "Testing Fermion Actions: Scaling in the Schwinger Model: We test the scaling behaviour of Wilson, hypercube, maximally twisted mass\nand overlap fermion actions in dynamical simulations of the 2-dimensional\nmassive Schwinger model. We also present possibilities to simulate overlap\nfermions dynamically by replacing the exact overlap operator by an approximate\nversion. This approximation is used either as only the guidance Hamiltonian,\nkeeping the exact overlap operator as the accept/reject Hamiltonian or for\nboth, the guidance and accept/reject Hamiltonian in the Hybrid Monte Carlo\nalgorithm. In the latter case we test whether the approximation error can be\ncorrected for by computing the determinant ratio of the exact and the\napproximate overlap operators stochastically.",
        "positive": "Review of Hadron Structure Calculations on a Lattice: I present a review of the current status and the most recent achievements in\nlattice QCD calculations of hadron structure. First, I overview the status and\nsystematic uncertainties of nucleon structure \"benchmark\" quantities that are\nwell known from experiments and serve as a reference point for the validity of\nlattice QCD methods. Next, I discuss the current status of calculations of form\nfactors of the nucleon and highlight some recent results for other hadrons that\nare important for understanding their internal dynamics. Wave functions of\nhadrons and their excitations may also be studied in lattice QCD, and I\nillustrate it with two recent examples of such calculations. Finally, I discuss\nin detail the state of calculations pertaining to the nucleon spin puzzle."
    },
    {
        "anchor": "Recent results on the Equation of State of QCD: We report on a continuum extrapolated result (arXiv:1309.5258) for the\nequation of state (EoS) of QCD with $N_f=2+1$ dynamical quark flavors and\ndiscuss preliminary results obtained with an additional dynamical charm quark\n($N_f=2+1+1$). For all our final results, the systematics are controlled, quark\nmasses are set to their physical values, and the continuum limit is taken using\nat least three lattice spacings corresponding to temporal extents up to\n$N_t=16$.",
        "positive": "The Chiral Condensate of One-Flavor QCD and the Dirac Spectrum at\n  \u03b8=0: In a sector of fixed topological charge, the chiral condensate has a\ndiscontinuity given by the Banks-Casher formula also in the case of one-flavor\nQCD. However, at fixed \\theta-angle, the chiral condensate remains constant\nwhen the quark mass crosses zero. To reconcile these contradictory\nobservations, we have evaluated the spectral density of one-flavor QCD at\n\\theta=0. For negative quark mass, it becomes a strongly oscillating function\nwith a period that scales as the inverse space-time volume and an amplitude\nthat increases exponentially with the space-time volume. As we have learned\nfrom QCD at nonzero chemical potential, if this is the case, an alternative to\nthe Banks-Casher formula applies, and as we will demonstrate in this talk, for\none-flavor QCD this results in a continuous chiral condensate. A special role\nis played by the topological zero modes which have to be taken into account\nexactly in order to get a finite chiral condensate in the thermodynamic limit."
    },
    {
        "anchor": "Ground state mass in short lattices by controlling overconfidence and\n  bias in Bayesian fits: We investigate the seemingly ill-defined problem of extracting a ground-state\nmass from a lattice simulation where the extent of the lattice is not long\nenough to project out the ground-state properly. We regulate the problem using\na Bayesian method. We show that controlling meta-parameters (overconfidence)\ncan allow the data to overcome the input priors (bias). We can write the method\nas a black-box technique which allows extraction of a ground-state mass, even\non a relatively short lattice.",
        "positive": "Series studies of the Potts model. II: Bulk series for the square\n  lattice: The finite lattice method of series expansion has been used to extend\nlow-temperature series for the partition function, order parameter and\nsusceptibility of the $q$-state Potts model to order $z^{56}$ (i.e. $u^{28}$),\n$z^{47}$, $z^{43}$, $z^{39}$, $z^{39}$, $z^{39}$, $z^{35}$, $z^{31}$ and\n$z^{31}$ for $q = 2$, 3, 4, \\dots 9 and 10 respectively. These series are used\nto test techniques designed to distinguish first-order transitions from\ncontinuous transitions. New numerical values are also obtained for the\n$q$-state Potts model with $q>4$."
    },
    {
        "anchor": "Hunting for the strangeness content of the nucleon: We present results for the strangeness contribution to the nucleon, <N|ss|N>,\nand to the spin of the nucleon, Delta s. By combining several variance\nreduction techniques for all-to-all propagators we are able to obtain gains in\nterms of computer time of factors of 25-30 for the disconnected loop that is\nneeded within the calculation of Delta s, relative to the standard approach of\njust employing time partitioning/dilution. For <N|ss|n>, the error is dominated\nby the gauge noise.",
        "positive": "A Possible Lack of Phase Transition in SO(3) Lattice Gauge Theory on\n  Lattices with Two Temporal Sites: This paper is being withdrawn as its main results are already included in\nsection 2 of the paper hep-lat/9901006."
    },
    {
        "anchor": "QCD phase diagram from the lattice at strong coupling: The phase diagram of lattice QCD in the strong coupling limit can be measured\nin the full $\\mu$-$T$ plane, also in the chiral limit. In particular, the phase\ndiagram in the chiral limit features a tricritical point at some $(\\mu_c,T_c)$.\nThis point may be related to the critical end point expected in the QCD phase\ndiagram. We discuss the gauge corrections to the phase diagram at strong\ncoupling and compare our findings with various possible scenarios in continuum\nQCD. We comment on the possibility that the tricritical point at strong\ncoupling is connected to the tricritical point in the continuum, massless QCD.",
        "positive": "Setting the scale for the Luescher-Weisz action: We study the quark-antiquark potential of quenched SU(3) lattice gauge theory\nwith the Luescher-Weisz action. After blocking the gauge fields with the\nrecently proposed hypercubic transformation we compute the Sommer parameter,\nextract the lattice spacing a and set the scale at 6 different values of the\ngauge coupling in a range from a = 0.084 fm to 0.136 fm."
    },
    {
        "anchor": "The critical line from imaginary to real baryonic chemical potentials in\n  two-color QCD: The method of analytic continuation from imaginary to real chemical\npotentials $\\mu$ is one of the few available techniques to study QCD at finite\ntemperature and baryon density. One of its most appealing applications is the\ndetermination of the critical line for small $\\mu$: we perform a direct test of\nthe validity of the method in this case by studying two-color QCD, where the\nsign problem is absent. The (pseudo)critical line is found to be analytic\naround $\\mu^2 = 0$, but a very large precision would be needed at imaginary\n$\\mu$ to correctly predict the location of the critical line at real $\\mu$.",
        "positive": "Polarised correlators at finite temperature: QCD undergoes a deconfining transition at high temperature to a \"quark-gluon\nplasma\" phase where hadrons may become unbound. In this work, meson correlation\nfunctions at non-zero momentum are studied both in the confined and plasma\nphases using the Maximum Entropy Method. In particular, both the longitudinal\nand transverse modes of the vector correlation functions are considered. Only\nin the case of light quarks in the plasma phase, we find that both longitudinal\nand transverse spectral functions have a non-zero intercept at zero energy."
    },
    {
        "anchor": "Time windows of the muon HVP from twisted-mass lattice QCD: We present a lattice determination of the leading-order hadronic vacuum\npolarization (HVP) contribution to the muon anomalous magnetic moment,\n$a_{\\mu}^{\\rm HVP}$, in the so-called short and intermediate time-distance\nwindows, $a_{\\mu}^{\\rm SD}$ and $a_{\\mu}^{\\rm W}$. We employ gauge ensembles\nproduced by the Extended Twisted Mass Collaboration (ETMC) with $N_f = 2 + 1 +\n1$ flavours of Wilson-clover twisted-mass quarks with masses of all the\ndynamical quark flavours tuned close to their physical values. The simulations\nare carried out at three values of the lattice spacing equal to $\\simeq 0.057,\n0.068$ and $0.080$ fm with spatial lattice sizes up to $L \\simeq 7.6$~fm. For\nthe short distance window we obtain $a_\\mu^{\\rm SD} = 69.27\\,(34) \\cdot\n10^{-10}$, in agreement with the dispersive determination based on experimental\n$e^+ e^-$ data. For the intermediate window we get instead $a_\\mu^{\\rm W} =\n236.3\\,(1.3) \\cdot 10^{-10}$, which is consistent with recent determinations by\nother lattice collaborations, but disagrees with the dispersive determination\nat the level of $3.6\\,\\sigma$.",
        "positive": "An update on QCD+QED simulations with C* boundary conditions: We present two novelties in our analysis of fully dynamical QCD+QED ensembles\nwith C* boundary conditions. The first one is the explicit computation of the\nsign of the Pfaffian. We present an algorithm that provides a significant\nspeedup compared to traditional methods. The second one is a reweighting of the\nmass in the context of the RHMC. We have tested the techniques on both pure QCD\nand QCD+QED ensembles with pions at $m_{\\pi^\\pm}\\approx400$ MeV, a lattice\nspacing of $a\\approx0.05$ fm, a fine-structure constant of\n$\\alpha_{\\mathrm{R}}=0$ and $0.04$."
    },
    {
        "anchor": "Chiral symmetry restoration in static-light mesons: chiral restoration\n  theorem, the quark running mass m(k) and first chiral restoration signals in\n  the lattice QCD spectra: Chiral symmetry restoration high in the hadron spectra is expected but it\nremains to be confirmed both in lattice QCD computations and in experiments.\nRecently, a theorem was derived, relating chiral symmetry restoration high in\nthe hadron spectra to the spontaneous generation of the dynamical quark mass in\nQCD. We refine the theorem in the case of static-light mesons. Utilizing chiral\nquark model computations and lattice QCD results for the spectrum of mesons\ncomposed by a static antiquark and a light quark, we explore chiral symmetry\nrestoration in the spectrum and the quark running mass m(k).",
        "positive": "Alternative derivation of the relativistic three-particle quantization\n  condition: We present a simplified derivation of the relativistic three-particle\nquantization condition for identical, spinless particles described by a generic\nrelativistic field theory satisfying a $\\mathbb Z_2$ symmetry. The\nsimplification is afforded by using a three-particle quasilocal K matrix that\nis not fully symmetrized, $\\widetilde{\\mathcal{K}}_{\\rm df,3}^{(u,u)}$, and\nmakes extensive use of time-ordered perturbation theory (TOPT). We obtain a new\nform of the quantization condition. This new form can then be related\nalgebraically to the standard quantization condition, which depends on a fully\nsymmetric three-particle K matrix, $\\mathcal{K}_{\\rm df,3}$. The new derivation\nis fully explicit, allowing, for example, a closed-form expression for\n$\\mathcal{K}_{\\rm df,3}$ to be given in terms of TOPT amplitudes. The new form\nof the quantization condition is similar in structure to that obtained in the\n\"finite-volume unitarity\" approach, and in a companion paper we make this\nconnection concrete. Our simplified approach should also allow a more\nstraightforward generalization of the quantization condition to nondegenerate\nparticles, and perhaps also to more than three particles."
    },
    {
        "anchor": "The lattice gluon propagator into the next millennium: We evaluate numerically the momentum-space gluon propagator in the lattice\nLandau gauge, for three- and four-dimensional pure SU(2) lattice gauge theory.\nAlthough there are large finite-size effects, we always observe, in the limit\nof large lattice volumes, a gluon propagator decreasing in the infrared limit.\nThis result can be interpreted in a straightforward way, by considering the\nproximity of the so-called first Gribov horizon in the infrared directions. We\nalso consider the problem of discretization errors introduced by the lattice\nregularization, and their effect on the ultraviolet behavior of the gluon\npropagator.",
        "positive": "Properties of quark gluon plasma from lattice calculations: I discuss lattice QCD calculations of the properties of strongly interacting\nmatter at finite temperature, including the determination of the transition\ntemperature Tc, equation of state, different static screening lengths and\nquarkonium spectral functions. The lattice data suggest that at temperatures\nabove 2Tc many properties of the quark gluon plasma can be understood using\nweak coupling approach, although non-perturbative effects due to static\nmagnetic fields are significant in some quantities."
    },
    {
        "anchor": "Review on Algorithms for dynamical fermions: This review gives an overview on the research of algorithms for dynamical\nfermions used in large scale lattice QCD simulations.\n  First a short overview on the state-of-the-art of ensemble generation at the\nphysical point is given.\n  Followed by an overview on necessary steps towards simulation of large\nlattices with the Hybrid Monte Carlo algorithm. Here, the status of iterative\nsolvers and tuning procedures for numerical integrators within the molecular\ndynamics are discussed.\n  This is followed by a review on the on-going developments for algorithms,\nwith a focus on methods which are potentially useful to simulate gauge theories\nat very fine lattice spacings, i.e. well suited to overcome freezing of the\ntopological charge. This includes modification of the HMC algorithm as well as\na discussion of algorithms which includes the fermion weight via global\ncorrection steps. Parts of the discussions are on the application of generative\nmodels via gauge equivariant flows as well as multi-level algorithms.",
        "positive": "Colour Confinement in the Lattice Landau Gauge QCD Simulation: The colour confinement criterion proposed by Kugo and Ojima is tested in the\nlattice Landau gauge QCD simulation. The renormalization effects are studied by\nmeasuring the gluon propagator, ghost propagator, three gluon vertex and the\nghost-antighost-gluon vertex."
    },
    {
        "anchor": "Effective electroweak Hamiltonian in the gradient-flow formalism: The effective electroweak Hamiltonian in the gradient-flow formalism is\nconstructed for the current-current operators through next-to-next-to-leading\norder QCD. The results are presented for two common choices of the operator\nbasis. This paves the way for a consistent matching of perturbatively evaluated\nWilson coefficients and non-perturbative matrix elements evaluated by lattice\nsimulations.",
        "positive": "Effective lattice action for the configurations smeared by the Wilson\n  flow: We investigate a trajectory for the Wilson flow in the theory space. For this\npurpose, we determine the coefficient of the plaquette and rectangular terms in\nthe action for the configurations defined by the solution of the Wilson flow.\nThe demon method regarded as one of the inverse Monte Carlo methods is used for\nthe determination of them. Starting from the conventional Wilson plaquette\naction of quenched QCD, we find that the coefficient of the plaquette grows\nwhile that of the rectangular tends to negative with the development of the\nflow as the known improved actions. We also find that the trajectory forms a\nstraight line in the two-coupling theory space."
    },
    {
        "anchor": "Electrical conductivity and thermal dilepton rate from quenched lattice\n  QCD: We report on a continuum extrapolation of the vector current correlation\nfunction for light valence quarks in the deconfined phase of quenched QCD. This\nis achieved by performing a systematic analysis of the influence of cut-off\neffects on light quark meson correlators at $T\\simeq 1.45 T_c$ using clover\nimproved Wilson fermions. We discuss resulting constraints on the electrical\nconductivity and the thermal dilepton rate in a quark gluon plasma. In addition\nnew results at 1.2 and 3.0 $T_c$ will be presented.",
        "positive": "Effective Field Theories in a Finite Volume: In this talk I present the formalism we have used to analyze Lattice data on\ntwo meson systems by means of effective field theories. In particular I present\nthe results obtained from a reanalysis of the lattice data on the $KD^{(*)}$\nsystems, where the states $D^*_{s0}(2317)$ and $D^*_{s1}(2460)$ are found as\nbound states of $KD$ and $KD^*$, respectively. We confirm the presence of such\nstates in the lattice data and determine the contribution of the $KD$ channel\nin the wave function of $D^*_{s0}(2317)$ and that of $KD^*$ in the wave\nfunction of $D^*_{s1}(2460)$. Our findings indicate a large meson-meson\ncomponent in the two cases."
    },
    {
        "anchor": "Axial charges of N(1535) and N(1650) in lattice QCD with two flavors of\n  dynamical quarks: We show the first lattice QCD results on the axial charge $g_A^{N^*N^*}$ of\n$N^*(1535)$ and $N^*(1650)$. The measurements are performed with two flavors of\ndynamical quarks employing the renormalization-group improved gauge action at\n$\\beta$=1.95 and the mean-field improved clover quark action with the hopping\nparameters, $\\kappa$=0.1375, 0.1390 and 0.1400. In order to properly separate\nsignals of $N^*(1535)$ and $N^*(1650)$, we construct 2$\\times$2 correlation\nmatrices and diagonalize them. Wraparound contributions in the correlator,\nwhich can be another source of signal contaminations, are eliminated by\nimposing the Dirichlet boundary condition in the temporal direction. We find\nthat the axial charge of $N^*(1535)$ takes small values as $g_A^{N^*N^*}\\sim\n{\\mathcal O}(0.1)$, whereas that of $N^*(1650)$ is about 0.5, which is found\nindependent of quark masses and consistent with the predictions by the naive\nnonrelativistic quark model.",
        "positive": "Taylor expansion and the Cauchy Residue Theorem for finite-density QCD: We present an update on our efforts to determine the Taylor coefficients of\nthe $\\mu/T$ expansion of the pressure for finite-density QCD. Here, we explore\nalternatives based on the Cauchy Residue Theorem, which allows us to use a\ndiscretized contour to determine the desired spectral moments occurring in the\nTaylor expansion of QCD at zero chemical potential."
    },
    {
        "anchor": "Center-vortex dominance after dimensional reduction of SU(2) lattice\n  gauge theory: The high-temperature phase of SU(2) Yang-Mills theory is addressed by means\nof dimensional reduction with a special emphasis on the properties of center\nvortices. For this purpose, the vortex vacuum which arises from center\nprojection is studied in pure 3-dimensional Yang-Mills theory as well as in the\n3-dimensional adjoint Higgs model which describes the high temperature phase of\nthe 4-dimensional SU(2) gauge theory. We find center-dominance within the\nnumerical accuracy of 10%.",
        "positive": "SU(3) lattice QCD study for octet and decuplet baryon spectra: The spectra of octet and decuplet baryons are studied using SU(3) lattice QCD\nat the quenched level. As an implementation to reduce the statistical\nfluctuation, we employ the anisotropic lattice with $O(a)$ improved quark\naction. In relation to $\\Lambda(1405)$, we measure also the mass of the SU(3)\nflavor-singlet negative-parity baryon, which is described as a three quark\nstate in the quenched lattice QCD, and its lowest mass is measured about 1.6\nGeV. Since the experimentally observed negative-parity baryon $\\Lambda(1405)$\nis much lighter than 1.6 GeV, $\\Lambda(1405)$ may include a large component of\na $N \\bar K$ bound state rather than the three quark state. The mass splitting\nbetween the octet and the decuplet baryons are also discussed in terms of the\ncurrent quark mass."
    },
    {
        "anchor": "A complex path around the sign problem: We review recent attempts at dealing with the sign problem in Monte Carlo\ncalculations by deforming the region of integration in the path integral from\nreal to complex fields. We discuss the theoretical foundations, the algorithmic\nissues and present some results for low dimensional field theories in both\nimaginary and real time.",
        "positive": "Nucleon-Nucleon Scattering Parameters in the Limit of SU(3) Flavor\n  Symmetry: The scattering lengths and effective ranges that describe low-energy\nnucleon-nucleon scattering are calculated in the limit of SU(3)-flavor symmetry\nat the physical strange-quark mass with Lattice Quantum Chromodynamics. The\ncalculations are performed with an isotropic clover discretization of the quark\naction in three volumes with spatial extents of L \\sim 3.4 fm, 4.5fm and 6.7\nfm, and with a lattice spacing of b \\sim 0.145 fm. With determinations of the\nenergies of the two-nucleon systems (both of which contain bound states at\nthese up and down quark masses) at rest and moving in the lattice volume,\nLuscher's method is used to determine the low-energy phase shifts in each\nchannel, from which the scattering length and effective range are obtained. The\nscattering parameters, in the 1S0 channel are found to be m_pi a^(1S0) =\n9.50^{+0.78}_{-0.69}^{+1.10}_{-0.80} and m_pi r^(1S0) =\n{4.61^{+0.29}_{-0.31}^{+0.24}_{-0.26}, and in the 3S1 channel are m_pi a^(3S1)\n= 7.45^{+0.57}_{-0.53}^{+0.71}_{-0.49} and m_pi r^(3S1) =\n3.71^{+0.28}_{-0.31}^{+0.28}_{-0.35}. These values are consistent with the\ntwo-nucleon system exhibiting Wigner's supermultiplet symmetry, which becomes\nexact in the limit of large-N_c. In both spin channels, the phase shifts change\nsign at higher momentum, near the start of the t-channel cut, indicating that\nthe nuclear interactions have a repulsive core even at the SU(3)-symmetric\npoint."
    },
    {
        "anchor": "Baby Universes in 4d Dynamical Triangulation: We measure numerically the distribution of baby universes in the crumpled\nphase of the dynamical triangulation model of 4d quantum gravity. The relevance\nof the results to the issue of an exponential bound is discussed. The data are\nconsistent with the existence of such a bound.",
        "positive": "Point-to-point Hadron Correlation Functions using the\n  Sheikholeslami--Wohlert Action: We calculate correlations between hadronic current operators as a function of\ntheir spatial separation, in a quenched lattice QCD simulation at $\\beta=6.2$\non a $24^3\\times48$ lattice. The lattice fermion formulation used is that due\nto Sheikholeslami and Wohlert. The correlation functions are then compared with\nthe corresponding quantities calculated in the infinite volume chiral limit of\nthe non-interacting theory. The ratio of the two quantities contains\ninformation on the vacuum structure of QCD. Results obtained are consistent\nwith previous studies, and with known hadron phenomenology, although certain\nfeatures of the fermion action used make it impossible to probe the $r\\to0$\nlimit directly, thus limiting the accuracy possible."
    },
    {
        "anchor": "A lattice model with a theta term in three dimensions: We study a three-dimensional abelian lattice model in which the analogue of a\ntheta term can be defined. This term is defined by introducing a neutral scalar\nfield and its effect is to couple magnetic monopoles to the scalar field and\nvortices to the gauge field. An interesting feature of this model is the\npresence of an exact duality symmetry that acts on a three parameter space. It\nis shown that this model has an interesting phase structure for non-zero values\nof theta. In addition to the usual confinement and vortex phases there are\nphases in which loops with composite charges condense. The presence of novel\npoint like excitations also alters the physical properties of the system.",
        "positive": "Meson spectroscopy with derivative quark sources: We present results for masses of light mesons obtained with the variational\nmethod using an enhanced basis of interpolating field operators with different\nquark smearings. The interpolators are constructed from Jacobi-smeared quarks\nof a Gaussian type as well as from derivative quark sources obtained by a\ncovariant derivative acting on the Gaussian sources. For our analysis we use\nquenched gauge configurations with Chirally Improved quarks and the\nLuescher-Weisz gauge action on a 16^3 x 32 lattice with a = 0.148 fm. We\ndiscuss the influence of derivative sources on the overlap with excited states."
    },
    {
        "anchor": "Boundary states and Non-Abelian Casimir effect in lattice Yang-Mills\n  theory: Using first-principle numerical simulations, we investigate the Casimir\neffect in zero-temperature SU(3) lattice gauge theory in 3+1 spacetime\ndimensions. The Casimir interaction between perfect chromometallic mirrors\nreveals the presence of a new gluonic state with the mass $m_{\\mathrm{gt}} =\n1.0(1)\\sqrt{\\sigma} = 0.49(5)\\,\\mathrm{GeV} = 0.29(3) M_{0^{++}}$ which is\nsubstantially lighter than the $0^{++}$ groundstate glueball. We call this\nexcitation ``glueton'' interpreting it as a non-perturbative colorless state of\ngluons bound to their negatively colored images in the chromometallic mirror.\nThe glueton is a gluonic counterpart of a surface electron-hole exciton in\nsemiconductors. We also show that a heavy quark is attracted to the neutral\nchromometallic mirror, thus supporting the existence of a ``quarkiton'' (a\n``quark exciton'') colorless state in QCD, which is formed by a single quark\nwith its anti-quark image in the chromometallic mirror. Analogies with edge\nmodes in topological insulators and boundary states of fractional vortices in\nmulti-component condensates are highlighted.",
        "positive": "A model-independent framework for determining finite-volume effects of\n  spatially nonlocal operators: We present a model-independent framework to determine finite-volume\ncorrections of matrix elements of spatially-separated current-current\noperators. We define these matrix elements in terms of Compton-like amplitudes,\ni.e. amplitudes coupling single-particle states via two current insertions. We\nshow that the infrared behavior of these matrix elements is dominated by the\nsingle-particle pole, which is approximated by the elastic form factors of the\nlowest-lying hadron. Therefore, given lattice data on the relevant elastic form\nfactors, the finite-volume effects can be estimated non-perturbatively and\nwithout recourse to effective field theories. For illustration purposes, we\ninvestigate the implications of the proposed formalism for a class of scalar\ntheories in two and four dimensions."
    },
    {
        "anchor": "Quark mass dependence of on-shell and half off-shell scattering\n  amplitudes from Bethe-Salpeter wave function inside the interaction range: We evaluate scattering amplitudes at on-shell and half off-shell for $I=2$\nS-wave two-pion system using the Bethe-Salpeter wave function inside the\ninteraction range in the quenched QCD. The scattering length and effective\nrange are extracted from these scattering amplitudes. Quark mass dependence of\nthem is investigated with the pion mass ranged in $0.52$--$0.86$~GeV. We\nexamine consistency between a result by the conventional finite volume method\nand our estimate, as well as the phenomenological value.",
        "positive": "A qubit regularization of the $O(3)$ sigma model: We construct a qubit regularization of the $O(3)$ non-linear sigma model in\ntwo and three spatial dimensions using a quantum Hamiltonian with two qubits\nper lattice site. Using a worldline formulation and worm algorithms, we show\nthat in two spatial dimensions our model has a quantum critical point where the\nwell-known scale-invariant physics of the three-dimensional Wilson-Fisher fixed\npoint is reproduced. In three spatial dimensions, we recover mean-field\ncritical exponents at a similar quantum critical point. These results show that\nour qubit Hamiltonian is in the same universality class as the traditional\nclassical lattice model close to the critical points. Simple modifications to\nour model also allow us to study the physics of traditional lattice models with\n$O(2)$ and $Z_2$ symmetries close to the corresponding critical points."
    },
    {
        "anchor": "RG-running of the tensor currents for $N_f$ =3 QCD in a $\u03c7SF$ setup: We present the preliminary results of the non-perturbative running of the\nflavour non-singlet tensor operator in the high-energy range\n$2~\\rm{GeV}\\lesssim \\mu\\lesssim 128~\\rm{GeV}$ in $N_f=3$ massless QCD,\ncomparing four different definitions of the renormalisation constant. We use\nthe configuration ensembles of arXiv:1802.05243 and arXiv:1607.06423, subject\nto Schr\\\"odinger functional (SF) boundary conditions, and valence quarks with\nchirally rotated Schr\\\"odinger functional ($\\chi$SF) boundary conditions.\nProvided that boundary counterterms have been appropriately tuned, this results\nin O($a$) improvement of the tensor operator, without the need of a dimension-4\nSymanzik counterterm (proportional to $c_T$).",
        "positive": "Quenched QED on a momentum space lattice: We discuss the advantages of using the momentum space lattice method for\nstudying the phase diagram of quenched QED_4. Preliminary results of a\nnumerical simulation are presented. They indicate that the method avoids the\ncontamination by 4-fermi interactions which plagues the conventional position\nspace non-compact formulation."
    },
    {
        "anchor": "The Coleman-Weinberg Mechanism and First Order Phase Transitions: Revised and reduced the size of the text. Removed figure 2 in previous text.\nSo, old figure 3 and 4 become new figure 2 and 3, respectively. Added figure 4\nfor first order phase transition observation in the strong coupling region.\nPostscript files for the figures are available upon request. To be published in\nPhys. Lett. B.",
        "positive": "Comparison of different source calculations in two-nucleon channel at\n  large quark mass: We investigate a systematic error coming from higher excited state\ncontributions in the energy shift of light nucleus in the two-nucleon channel\nby comparing two different source calculations with the exponential and wall\nsources. Since it is hard to obtain a clear signal of the wall source\ncorrelation function in a plateau region, we employ a large quark mass as the\npion mass is 0.8 GeV in quenched QCD. We discuss the systematic error in the\nspin-triplet channel of the two-nucleon system, and the volume dependence of\nthe energy shift."
    },
    {
        "anchor": "Extracting excited states from lattice QCD: the Roper resonance: We present a new method for extracting excited states from a single two-point\ncorrelation function calculated on the lattice. Our method simply combines the\ncorrelation function evaluated at different time slices so as to ``subtract''\nthe leading exponential decay (ground state) and to give access to the first\nexcited state. The method is applied to a quenched lattice study (volume = 24^3\nx 64, beta = 6.2, 1/a = 2.55 GeV) of the first excited state of the nucleon\nusing the local interpolating operator O = [uT C gamma5 d] u. The results are\nconsistent with the identification of our extracted excited state with the\nRoper resonance N'(1440). The switching of the level ordering with respect to\nthe negative-parity partner of the nucleon, N*(1535), is not seen at the\nsimulated quark masses and, basing on crude extrapolations, is tentatively\nexpected to occur close to the physical point.",
        "positive": "N-vector spin models on the sc and the bcc lattices: a study of the\n  critical behavior of the susceptibility and of the correlation length by high\n  temperature series extended to order beta^{21}: High temperature expansions for the free energy, the susceptibility and the\nsecond correlation moment of the classical N-vector model [also known as the\nO(N) symmetric classical spin Heisenberg model or as the lattice O(N) nonlinear\nsigma model] on the sc and the bcc lattices are extended to order beta^{21} for\narbitrary N. The series for the second field derivative of the susceptibility\nis extended to order beta^{17}. An analysis of the newly computed series for\nthe susceptibility and the (second moment) correlation length yields updated\nestimates of the critical parameters for various values of the spin\ndimensionality N, including N=0 [the self-avoiding walk model], N=1 [the Ising\nspin 1/2 model], N=2 [the XY model], N=3 [the Heisenberg model]. For all values\nof N, we confirm a good agreement with the present renormalization group\nestimates. A study of the series for the other observables will appear in a\nforthcoming paper."
    },
    {
        "anchor": "Chiral symmetry and lattice gauge theory: I review the problem of formulating chiral symmetry in lattice gauge theory.\nI discuss recent approaches involving an infinite tower of additional heavy\nstates to absorb Fermion doublers. For hadronic physics this provides a natural\nscheme for taking quark masses to zero without requiring a precise tuning of\nparameters. A mirror Fermion variation provides a possible way of extending the\npicture to chirally coupled light Fermions. Talk presented at \"Quark\nConfinement and the Hadron Spectrum,\" Como, Italy, 20-24 June 1994.",
        "positive": "Time evolution of linearized gauge field fluctuations on a real-time\n  lattice: Classical real-time lattice simulations play an important role in\nunderstanding non-equilibrium phenomena in gauge theories and are used in\nparticular to model the prethermal evolution of heavy-ion collisions. Due to\ninstabilities, small quantum fluctuations on top of the classical background\nmay significantly affect the dynamics of the system. In this paper we argue for\nthe need for a numerical calculation of a system of classical gauge fields and\nsmall linearized fluctuations in a way that keeps the separation between the\ntwo manifest. We derive and test an explicit algorithm to solve these equations\non the lattice, maintaining gauge invariance and Gauss's law."
    },
    {
        "anchor": "U(1) Lattice Gauge theory and its Dual: The three dimensional U(1) Lattice Gauge, in the weak coupling limit, is dual\nto a Discrete Gaussian model. We investigate this dual model and use it to\ncalculate properties of the U(1) theory. We find that, because of the nature of\nthe dual model, its advantages are outweighed by large autocorrelation times\ngenerated when the dual system becomes disordered.",
        "positive": "Gauge-invariant two- and three- density correlators: Gauge-invariant spatial correlations between two and three quarks inside a\nhadron are measured within quenched and unquenched QCD. These correlators\nprovide information on the shape and multipole moments of the pion, the rho,\nthe nucleon and the $\\Delta$."
    },
    {
        "anchor": "On Complex Langevin Dynamics and the Evaluation of Observables: In stochastic quantisation, quantum mechanical expectation values are\ncomputed as averages over the time history of a stochastic process described by\na Langevin equation. Complex stochastic quantisation, though theoretically not\nrigorously established, extends this idea to cases where the action is\ncomplex-valued by complexifying the basic degrees of freedom, all observables\nand allowing the stochastic process to probe the complexified configuration\nspace. We review the method for a previously studied one-dimensional toy model,\nthe U(1) one link model. We confirm that complex Langevin dynamics only works\nfor a certain range of parameters, misestimating observables otherwise. A\ncurious effect is observed where all moments of the basic stochastic variable\nare misestimated, although these misestimated moments may be used to construct,\nby a Taylor series, other observables that are reproduced correctly. This\nsuggests a subtle but not completely resolved relationship between the original\ncomplex integration measure and the higher-dimensional probability distribution\nin the complexified configuration space, generated by the complex Langevin\nprocess.",
        "positive": "The QCD equation of state with 2+1 flavors of Highly Improved Staggered\n  Quarks (HISQ): One of the fundamental properties of the quark-gluon plasma (QGP), the\nequation of state, is a subject of extensive studies in lattice QCD and an\nessential requirement for the correct hydrodynamic modeling of heavy-ion\ncollisions. Lattice QCD provides first-principle calculations for the physics\nin the non-perturbative regime. In this contribution, we report on recent\nprogress by the HotQCD collaboration in studying the 2+1 flavor equation of\nstate on lattices with the temporal extent N_tau=6, 8, 10 and 12 in Highly\nImproved Staggered Quarks (HISQ) discretization scheme. Comparisons with\nequation of state calculations with different fermion actions are also\ndiscussed."
    },
    {
        "anchor": "Precision Charmonium Spectroscopy From Lattice QCD: We present results for Charmonium spectroscopy using Non-Relativistic QCD\n(NRQCD). For the NRQCD action the leading order spin-dependent and next to\nleading order spin-independent interactions have been included with\ntadpole-improved coefficients. We use multi-exponential fits to multiple\ncorrelation functions to extract ground and excited $S$ states. Splittings\nbetween the lowest $S$, $P$ and $D$ states are given and we have accurate\nvalues for the $S$ state hyperfine splitting and the $\\chi_c$ fine structure.\nAgreement with experiment is good - the remaining systematic errors are\ndiscussed.",
        "positive": "Jet quenching in a strongly interacting plasma - A lattice approach: The phenomenon of jet quenching, related to the momentum broadening of a\nhigh-energy parton, provides important experimental evidence for the production\nof a strongly coupled, deconfined medium in heavy-ion collisions. Its\ntheoretical description has been addressed in a number of works, both\nperturbatively and non-perturbatively (using the gauge-gravity duality). In\nthis contribution, following a proposal by Caron-Huot, we discuss a novel\napproach to this problem, enabling one to extract non-perturbative information\non this real-time phenomenon from simulations on a Euclidean lattice."
    },
    {
        "anchor": "Implementation of the conjugate gradient algorithm for heterogeneous\n  systems: Lattice QCD calculations require significant computational effort, with the\ndominant fraction of resources typically spent in the numerical inversion of\nthe Dirac operator. One of the simplest methods to solve such large and sparse\nlinear systems is the conjugate gradient (CG) approach. In this work we present\nan implementation of CG that can be executed on different devices, including\nCPUs, GPUs, and FPGAs. This is achieved by using the SYCL/DPC++ framework,\nwhich allows the execution of the same source code on heterogeneous systems.",
        "positive": "Condensate Enhancement and D-Meson Mixing in Technicolor Theories: Since the pioneering work of Eichten and Lane it has been known that the\nscale of the interactions responsible for the generation of the strange-quark\nmass in extended technicolor theories must, absent any \"GIM-like\" mechanism for\nsuppressing flavor-changing neutral currents, be greater than of order 1000\nTeV. In this note we point out that the constraint from the neutral D-meson\nsystem is now equally strong, implying that the charm quark mass must also\narise from flavor dynamics at a scale this high. We then quantify the degree to\nwhich the technicolor condensate must be enhanced in order to yield the\nobserved quark masses, if the extended technicolor scale is of order 1000 TeV.\nOur results are intended to provide a framework in which to interpret and apply\nthe results of lattice studies of conformal strongly interacting gauge\ntheories, and the corresponding numerical measurements of the anomalous\ndimension of the mass operator in candidate theories of \"walking\" technicolor."
    },
    {
        "anchor": "Measuring the ground-state wave functional of SU(2) Yang-Mills theory in\n  3+1 dimensions: Abelian plane waves: A method of measuring relative probabilities of various gauge-field\nconfigurations in the Yang-Mills vacuum was proposed long ago [Phys. Lett. B\n223 (1989) 207]. We applied this method to compute the square of the YM vacuum\nwave functional (VWF) in numerical simulations of SU(2) lattice gauge theory in\nD=3+1 dimensions for sets of abelian plane waves. The results were compared to\npredictions based on some VWF proposals in the literature. None of them\ndescribes the data satisfactorily at large plane-wave momenta. The\nphenomenological best fit to data, containing three free parameters, appears to\nreduce in the continuum limit to the approximate form proposed in [Phys. Rev. D\n77 (2008) 065003].",
        "positive": "The Spontaneous Breaking of Chiral Symmetry without Goldstone Bosons: Considering a self-interaction only of mirror fermions in the context of a\nlattice-regularized fermion field theory, we show that the system undergoes\nspontaneous breaking of chiral symmetry and mirror-fermion masses are\ngenerated. However, it is explicitly shown that there are no Goldstone bosons\nappearing together with this spontaneous symmetry breaking phenomenon, since\nLorentz invariance, one of very general prerequisites of the Goldstone theorem,\nis violated. The result and its possible application are briefly discussed."
    },
    {
        "anchor": "Scaling and higher twist in the nucleon Compton amplitude: The partonic structure of hadrons plays an important role in a vast array of\nhigh-energy and nuclear physics experiments. It also underpins the theoretical\nunderstanding of hadron structure. Recent developments in lattice QCD offer new\nopportunities for reliably studying partonic structure from first principles.\nHere we report on the use of the Feynman-Hellmann theorem to study the forward\nCompton amplitude in the unphysical region. We demonstrate how this amplitude\nprovides direct constraint on hadronic inelastic structure functions. The use\nof external momentum transfer allows us to study the $Q^2$ evolution to explore\nthe onset of asymptotic scaling and reveal higher-twist effects in partonic\nstructure.",
        "positive": "A study of symmetry breaking in a relativistic Bose gas using the\n  contraction algorithm: A relativistic Bose gas at finite density suffers from a sign problem that\nmakes direct numerical simulations not feasible. One possible solution to the\nsign problem is to re-express the path integral in terms of Lefschetz thimbles.\nUsing this approach we study the relativistic Bose gas both in the symmetric\nphase (low-density) and the spontaneously broken phase (high-density). In the\nhigh-density phase we break explicitly the symmetry and determine the\ndependence of the order parameter on the breaking. We study the relative\ncontributions of the dominant and sub-dominant thimbles in this phase. We find\nthat the sub-dominant thimble only contributes substantially when the explicit\nsymmetry breaking is small, a regime that is dominated by finite volume\neffects. In the regime relevant for the thermodynamic limit, this contribution\nis negligible."
    },
    {
        "anchor": "Why a Particle Physicist is Interested in DNA Branch Migration: We describe an explicitly discrete model of the process of DNA branch\nmigration. The model matches the existing data well, but we find that branch\nmigration along long strands of DNA ($N \\simge 40$~bp) is also well modeled by\ncontinuum diffusion. The discrete model is still useful for guiding future\nexperiments.",
        "positive": "Sphaleron rate as an inverse problem: a novel lattice approach: We compute the sphaleron rate on the lattice. We adopt a novel strategy based\non the extraction of the spectral density via a modified version of the\nBackus-Gilbert method from finite-lattice-spacing and finite-smoothing-radius\nEuclidean topological charge density correlators. The physical sphaleron rate\nis computed by performing controlled continuum limit and zero-smoothing\nextrapolations both in pure gauge and, for the first time, in full QCD."
    },
    {
        "anchor": "Fixed versus random triangulations in 2D simplicial Regge calculus: We study 2D quantum gravity on spherical topologies using the Regge calculus\napproach with the $dl/l$ measure. Instead of a fixed non-regular triangulation\nwhich has been used before, we study for each system size four different random\ntriangulations, which are obtained according to the standard Voronoi-Delaunay\nprocedure. We compare both approaches quantitatively and show that the\ndifference in the expectation value of $R^2$ between the fixed and the random\ntriangulation depends on the lattice size and the surface area $A$. We also try\nagain to measure the string susceptibility exponents through a finite-size\nscaling Ansatz in the expectation value of an added $R^2$ interaction term in\nan approach where $A$ is held fixed. The string susceptibility exponent\n$\\gamma_{str}'$ is shown to agree with theoretical predictions for the sphere,\nwhereas the estimate for $\\gamma_{str}$ appears to be too negative.",
        "positive": "Scalar mesons in a finite volume: Using effective field theory methods, we discuss the extraction of the mass\nand width of the scalar mesons f0(980) and a0(980) from the finite-volume\nspectrum in lattice QCD. In particular, it is argued that the nature of these\nstates can be studied by invoking twisted boundary conditions, as well as\ninvestigating the quark mass dependence of the spectrum."
    },
    {
        "anchor": "Free energy of a static quark anti-quark pair and the renormalized\n  Polyakov loop in three flavor QCD: We study the free energy of a static quark anti-quark pair at finite\ntemperature in three flavor QCD with degenerate quark masses using N_tau=4 and\n6 lattices with Asqtad staggered fermion action. The static free energy was\ncalculated for different values of the quark mass and the entropy contribution\nat large distances has been extracted. We also calculate the renormalized\nPolyakov loop following the approach by Kaczmarek et al.",
        "positive": "Delta I = 3/2, K to Pi Pi Decays with a Nearly Physical Pion Mass: The Delta I = 3/2 K to Pi Pi decay amplitude is calculated on RBC/UKQCD 32^3\nx 64, L_s=32 dynamical lattices with 2+1 flavors of domain wall fermions using\nthe DSDR and Iwasaki gauge action. The calculation is performed with a single\npion mass (m_pi=141.9(2.3) MeV, partially quenched) and kaon mass\n(m_K=507.4(8.5) MeV) which are nearly physical, and with nearly energy\nconserving kinematics. Antiperiodic boundary conditions in two spatial\ndirections are used to give the two pions non-zero ground state momentum.\nResults for time separations of 20, 24, 28 and 32 between the kaon and two-pion\nsources are computed and an error weighted average is performed to reduce the\nerror. We find prelimenary results for Re(A_2)=1.396(081)_stat(160)_sys x\n10^(-8) GeV and Im(A_2) = -8.46(45)_stat(1.95)_sys x 10^(-13) GeV."
    },
    {
        "anchor": "Infrared behavior of the Faddeev-Popov operator in Coulomb gauge QCD: We calculate the eigenvalue distribution of the Faddeev-Popov operator in\nCoulomb gauge QCD using quenched SU(3) lattice simulation. In the confinement\nphase, the density of the low-lying eigenvalues increases with lattice volume,\nand the confinement criterion is satisfied. Moreover, even in the deconfinement\nphase, the behavior of the FP eigenvalue density is qualitatively the same as\nin the confinement phase. This is consistent with the fact that the\ncolor-Coulomb potential is not screened in the deconfined phase.",
        "positive": "Lattice Quantum Gravity: Review and Recent Developments: We review the status of different approaches to lattice quantum gravity\nindicating the successes and problems of each. Recent developments within the\ndynamical triangulation formulation are then described. Plenary talk at LATTICE\n95 July 11-15, Melbourne, Australia."
    },
    {
        "anchor": "Lattice Studies of 3D Maximally Supersymmetric Yang--Mills: We present ongoing investigations of maximally supersymmetric Yang--Mills ($Q\n= 16$ SYM) theory in three space-time dimensions. At low temperatures and large\n$N$ this theory is related to black branes in higher-dimensional quantum\ngravity. Building on previous work that focused on the homogeneous `D2' phase\nof the theory, we are now exploring phase transitions between this D2 phase and\nthe localized `D0' phase.",
        "positive": "The Shifted Coupled Cluster Method: A New Approach to Hamiltonian\n  Lattice Gauge Theories: It is shown how to adapt the non-perturbative coupled cluster method of\nmany-body theory so that it may be successfully applied to Hamiltonian lattice\n$SU(N)$ gauge theories. The procedure involves first writing the wavefunctions\nfor the vacuum and excited states in terms of linked clusters of gauge\ninvariant excitations of the strong coupling vacuum. The fundamental\napproximation scheme then consists of i) a truncation of the infinite set of\nclusters in the wavefunctions according to their geometric {\\em size}, with all\nlarger clusters appearing in the Schr\\\"odinger equations simply discarded, ii)\nan expansion of the truncated wavefunctions in terms of the remaining clusters\nrearranged, or ``shifted'', to describe gauge invariant {\\em fluctuations}\nabout their vacuum expectation values. The resulting non-linear truncated\nSchr\\\"odinger equations are then solved self-consistently and exactly. Results\nare presented for the case of $SU(2)$ in $d=3$ space-time dimensions."
    },
    {
        "anchor": "Central Charge of the Parallelogram Lattice Strong Coupling Schwinger\n  Model: We put forth a Fierzed hopping expansion for strong coupling Wilson fermions.\nAs an application, we show that the strong coupling Schwinger model on\nparallelogram lattices with nonbacktracking Wilson fermions span, as a function\nof the lattice skewness angle, the $\\Delta = -1$ critical line of $6$-vertex\nmodels. This Fierzed formulation also applies to backtracking Wilson fermions,\nwhich as we describe apparently correspond to richer systems. However, we have\nnot been able to identify them with exactly solved models.",
        "positive": "Sample size effects in multivariate fitting of correlated data: A common problem in analysis of experiments or in lattice QCD simulations is\nfitting a parameterized model to the average over a number of samples of\ncorrelated data values. If the number of samples is not infinite, estimates of\nthe variance of the parameters (\"error bars\") and of the goodness of fit are\naffected. We illustrate these problems with numerical simulations, and\ncalculate approximate corrections to the variance of the parameters for\nestimates made in the standard way from derivatives of the parameters'\nprobability distribution as well as from jackknife and bootstrap estimates."
    },
    {
        "anchor": "Stochastic quantization at finite chemical potential: A nonperturbative lattice study of QCD at finite chemical potential is\ncomplicated due to the complex fermion determinant and the sign problem. Here\nwe apply the method of stochastic quantization and complex Langevin dynamics to\nthis problem. We present results for U(1) and SU(3) one link models and QCD at\nfinite chemical potential using the hopping expansion. The phase of the\ndeterminant is studied in detail. Even in the region where the sign problem is\nsevere, we find excellent agreement between the Langevin results and exact\nexpressions, if available. We give a partial understanding of this in terms of\nclassical flow diagrams and eigenvalues of the Fokker-Planck equation.",
        "positive": "Scaling and Asymptotic Scaling in the SU(2) Gauge Theory: We determine the critical couplings for the deconfinement phase transition in\n$SU(2)$ gauge theory on $N_\\tau \\times N_\\sigma^3$ lattices with $N_\\tau = 8$\nand 16 and $N_\\sigma$ varying between 16 and 48. A comparison with string\ntension data shows scaling of the ratio $T_c / \\sqrt{\\sigma}$ in the entire\ncoupling regime $\\beta =2.30-2.75$, while the individual quantities still\nexhibit large scaling violations. We find $T_c / \\sqrt{\\sigma}=0.69(2)$. We\nalso discuss in detail the extrapolation of $T_c / Lambda_{\\rm{\\bar{M}\n\\bar{S}}}$ and $\\sqrt{\\sigma} / Lambda_{\\rm{\\bar{M}\\bar{S}}}$ to the continuum\nlimit. Our result, which is consistent with the above ratio, is $T_c /\nLambda_{\\rm{\\bar{M}\\bar{S}}} = 1.23(11)$ and $\\sqrt{\\sigma} /\nLambda_{\\rm{\\bar{M}\\bar{S}}} = 1.79(12)$. We also comment upon corresponding\nresults for $SU(3)$ gauge theory and four flavour QCD."
    },
    {
        "anchor": "Light- and strange-quark mass dependence of the $\u03c1(770)$ meson\n  revisited: Recent lattice data on $\\pi\\pi$-scattering phase shifts in the\nvector-isovector channel, pseudoscalar meson masses and decay constants for\nstrange-quark masses smaller or equal to the physical value allow us to study\nthe strangeness dependence of these observables for the first time. We perform\na global analysis on two kind of lattice trajectories depending on whether the\nsum of quark masses or the strange-quark mass is kept fixed to the physical\npoint. The quark mass dependence of these observables is extracted from\nunitarized coupled-channel one-loop Chiral Perturbation Theory. This analysis\nguides new predictions on the $\\rho(770)$ meson properties over trajectories\nwhere the strange-quark mass is lighter than the physical mass, as well as on\nthe SU(3) symmetric line. As a result, the light- and strange-quark mass\ndependence of the $\\rho(770)$ meson parameters are discussed and precise values\nof the Low Energy Constants present in unitarized one-loop Chiral Perturbation\nTheory are given. Finally, the current discrepancy between two- and\nthree-flavor lattice results for the $\\rho(770)$ meson is studied.",
        "positive": "Oscillating propagators in heavy-dense QCD: Using Monte Carlo simulations and extended mean field theory calculations we\nshow that the $3$-dimensional $Z_3$ spin model with complex external fields has\nnon-monotonic spatial correlators in some regions of its parameter space. This\nmodel serves as a proxy for heavy-dense QCD in $(3+1)$ dimensions.\nNon-monotonic spatial correlators are intrinsically related to a complex mass\nspectrum and a liquid-like (or crystalline) behavior. A liquid phase could have\nimplications for heavy-ion experiments, where it could leave detectable signals\nin the spatial correlations of baryons."
    },
    {
        "anchor": "Renormalization of the \u0394B=2 four-quark operators in lattice NRQCD: We calculate perturbative renormalization constants for the \\Delta B=2\nfour-quark operators in lattice NRQCD.\n  Continuum operators \\bar{b}\\gamma_{\\mu}(1-\\gamma_5)q~\n  \\bar{b}\\gamma_{\\mu}(1-\\gamma_5)q and\n\\bar{b}(1-\\gamma_5)q~\\bar{b}(1-\\gamma_5)q, which are necessary in evaluating\nthe mass and width differences in $B^0_{d(s)}-\\bar{B}^0_{d(s)}$ systems, are\nmatched at one-loop with corresponding lattice operators constructed from the\nNRQCD heavy quarks and the ${\\cal O}(a)$-improved light quarks. Using these\nperturbative coefficients, we also reanalyse our previous simulation results\nfor the matrix elements of the above operators. Our new results are free from\nthe systematic error of ${\\cal O}(\\alpha_s/(aM_b))$ in contrast to the previous\nones with matching coefficients evaluated in the static limit.",
        "positive": "Overlap and domain wall fermions: what is the price of chirality?: In this contribution the costs of simulations employing domain wall and\noverlap fermions are estimated. In the discussion we will stay within the\nquenched approximation."
    },
    {
        "anchor": "Flavor number dependence of QCD at finite density by the complex\n  Langevin method: We discuss the flavor number dependence of QCD at low temperature and high\ndensity by the complex Langevin method. In our previous work, the complex\nLangevin method is confirmed to satisfy the criterion for correct convergence\nin certain regions, such as $\\mu_{\\rm q} / T = 5.2-7.2$ on $8^3 \\times 16$ and\n$\\mu_{\\rm q} / T = 1.6-9.6$ on $16^3 \\times 32$ using $N_{\\rm f} = 4$ staggered\nfermion at $\\beta = 5.7$. We extend this study to more realistic flavor cases,\n$N_{\\rm f} = 2, 2 + 1, 3$, using Wilson fermions. We present the flavor number\ndependence of the validity regions of the complex Langevin method and the quark\nnumber.",
        "positive": "GPU implementation of a Landau gauge fixing algorithm: We discuss how the steepest descent method with Fourier acceleration for\nLaudau gauge fixing in lattice SU(3) simulations can be implemented using CUDA.\nThe scaling of the gauge fixing code was investigated using a Tesla C2070 Fermi\narchitecture, and compared with a parallel CPU gauge fixing code."
    },
    {
        "anchor": "Charmed hadron spectroscopy on the lattice for $N_f=2+1$ flavours: We study the spectra of charmonia, charmed mesons, singly and doubly charmed\nbaryons using Lattice QCD, with 2+1 flavours of fermions. In the case of\nmesons, we include higher spin states, while for baryons, both positive and\nnegative parity channels were investigated. By means of the variational method,\nwe were able to extract a clean signal from the correlation functions and\ninformation about the excited states.",
        "positive": "The local structure of topological charge fluctuations in QCD: We introduce the Dirac eigenmode filtering of topological charge density\nassociated with Ginsparg-Wilson fermions as a tool to investigate the local\nstructure of topological charge fluctuations in QCD. The resulting framework is\nused to demonstrate that the bulk of topological charge in QCD does not appear\nin the form of unit quantized lumps. This means that the mixing of \"would-be\"\nzeromodes associated with such lumps is probably not the prevalent microscopic\nmechanism for spontaneous chiral symmetry breaking in QCD. To characterize the\ncoherent local behavior in topological charge density at low energy, we compute\nthe charges contained in maximal coherent spheres enclosing non-overlapping\npeaks. We find a continuous distribution essentially ending at ~0.5. Finally,\nwe study, for the first time, the overlap-operator topological-charge-density\ncorrelators and find consistency with non-positivity at nonzero physical\ndistance. This represents a non-trivial check on the locality (in gauge paths)\nof the overlap Dirac operator for realistic gauge backgrounds."
    },
    {
        "anchor": "Spectroscopy of Charmed and Bottom Hadrons using Lattice QCD: We present preliminary results on the light, charmed and bottom baryon\nspectra using overlap valence quarks on the background of 2+1+1 flavours HISQ\ngauge configurations of the MILC collaboration. These calculations are\nperformed on three different gauge ensembles at three lattice spacings (a ~\n0.12 fm, 0.09 fm and 0.06 fm) and for physical strange, charm and bottom quark\nmasses. The SU(2) heavy baryon chiral perturbation theory is used to\nextrapolate baryon masses to the physical pion mass and the continuum limit\nextrapolations are also performed. Our results are consistent with the well\nmeasured charmed baryons. We predict the masses of many other states which are\nyet to be discovered.",
        "positive": "Matching coefficients for improved staggered bilinears: We calculate one-loop matching factors for bilinear operators composed of\nimproved staggered fermions. We compare the results for different improvement\nschemes used in the recent literature, including the HYP action and an action\nclose to the Asqtad action. We find that all improvement schemes substantially\nreduce the size of the one-loop contributions to matching factors. The\nresulting corrections are comparable to, or smaller than, those found with\nWilson and domain-wall fermions."
    },
    {
        "anchor": "Spectral functions of charmonium from 2 flavour anisotropic lattice data: The spectral functions of QCD can give us insight into properties of hadrons,\nand they are useful in probing the QCD vacuum. I will discuss the correlators\nand spectral functions of charmonium in high temperature two flavour QCD. The\nspectral functions have been obtained using the Maximum Entropy Method from\nanisotropic lattice data using the conserved vector current. This work has been\ndone as part of the FASTSUM collaboration. We find that the spectral functions\nfor zero momentum are stable. At non-zero momentum the spectral functions are\nless stable but still produce resonance and transport peaks. This work is part\nof our programme to calculate the heavy quark diffusion constant.",
        "positive": "Lattice QCD with the Overlap Fermions at Strong Gauge Coupling: We generalize overlap fermion by Narayanan and Neuberger by introducing a\nhopping parameter t. This lattice fermion has desirable properties as the\noriginal overlap fermion. We expand \"Dirac\" operator of this fermion in powers\nof t. Higher-order terms of t are long-distance terms and this t-expansion is a\nkind of the hopping expansion. It is shown that the Ginsparg-Wilson relation is\nsatisfied at each order of t. We show that this t-expansion is useful for study\nof the strong-coupling gauge theory. We apply this formalism to the lattice QCD\nand study its chiral phase structure at strong coupling. We find that there are\n(at least) two phases one of which has desired chiral properties of QCD.\nPossible phase structure of the lattice QCD with the overlap fermions is\nproposed."
    },
    {
        "anchor": "Conserved charge fluctuations with smaller-than-physical quark masses: We present results from calculations of conserved charge fluctuations in\n$(2+1)$-flavor QCD using light quark masses in the range $m_s/80 \\leq m_l \\leq\nm_s/27$, with the strange quark mass ($m_s$) kept fixed at its physical value.\nThis corresponds to a Goldstone pion mass in the range $80$ MeV $\\leq m_\\pi\n\\leq 140$ MeV. The measurements have been done using HISQ fermion\ndiscretization and Symanzik improved gauge action. We discuss the quark mass\ndependence of up to 6th order cumulants and present first results on the\nseparation of singular and regular contributions to these cumulants. From these\nresults, we examine the nature of the chiral phase transition and the variation\nof the curvature of the crossover line as we approach the chiral limit.",
        "positive": "Semileptonic decays of heavy-light pseudoscalar mesons: I discuss the results of a recent quenched lattice calculation of the two\nindependent form factors parametrizing the semileptonic decays between\nheavy-light pseudoscalar mesons. The differential decay rate of the process B\n--> D l nu has been calculated at non vanishing momentum transfer both in the\ncase of the light leptons, l=e,mu, and in the case of a non vanishing lepton\nmass, l=tau."
    },
    {
        "anchor": "The standard model and the lattice: I discuss some of the difficulties with formulating chiral symmetry on the\nlattice and review a recently proposed scheme for a fully finite and exactly\ngauge invariant lattice regularization of the standard model.",
        "positive": "Probability Distribution Function of the Diquark Condensate in Two\n  Colours QCD: We consider diquark condensation in finite density lattice SU(2). We first\npresent an extension of Vafa-Witten result, on spontaneous breaking of\nvector-like global symmetries, that allows us to formulate a no-go theorem for\ndiquark condensation in a region of the chemical potential-mass parameter\nspace. We then describe a new technique to calculate diquark condensation at\nany number of flavours directly at zero external source without using any\npotentially dangerous extrapolation procedure. We apply it to the strong\ncoupling limit and find compelling evidences for a second order phase\ntransition, where a diquark condensate appears, as well as quantitative\nagreement between lattice results and low-energy effective Lagrangian\ncalculations."
    },
    {
        "anchor": "The topological characteristics of lattice Dirac operators: We show that even if a lattice Dirac operator satisfies the conditions\nconsisting of locality, free of species doublings, correct continuum behavior,\n$\\gm5$-hermiticity and the Ginsparg-Wilson relation, it does not necessarily\nhave exact zero modes in nontrivial gauge backgrounds. This implies that each\nlattice Dirac operator has its own topological characteristics which cannot be\nfixed by these conditions. The role of topological characteristics in the axial\nanomaly is derived explicitly.",
        "positive": "Visualisation of Centre Vortex Structure: The centre vortex structure of the $SU(3)$ gauge field vacuum is explored\nthrough the use of novel visualisation techniques. The lattice is partitioned\ninto 3D time slices, and vortices are identified by locating plaquettes with\nnontrivial centre phases. Vortices are illustrated by rendering vortex lines\nthat pierce these nontrivial plaquettes. Nontrivial plaquettes with one\ndimension in the suppressed time direction are rendered by identifying the\nvisible spatial link. These visualisations highlight the frequent presence of\nsingular points and reveal an important role for branching points in $SU(3)$\ngauge theory in creating high topological charge density regimes.\nVisualisations of the topological charge density are presented, and an\ninvestigation into the correlation between vortex structures and topological\ncharge density is conducted. The results provide new insight into the\nmechanisms by which centre vortices generate nontrivial gauge field topology.\nThis work demonstrates the utility of visualisations in conducting centre\nvortex studies, presenting new avenues with which to investigate this\nperspective of the QCD vacuum."
    },
    {
        "anchor": "GomalizingFlow.jl: A Julia package for Flow-based sampling algorithm for\n  lattice field theory: GomalizingFlow.jl: is a package to generate configurations for quantum field\ntheory on the lattice using the flow based sampling algorithm in Julia\nprogramming language. This software serves two main purposes: to accelerate\nresearch of lattice QCD with machine learning with easy prototyping, and to\nprovide an independent implementation to an existing public Jupyter notebook in\nPython/PyTorch. GomalizingFlow.jl implements, the flow based sampling\nalgorithm, namely, RealNVP and Metropolis-Hastings test for two dimension and\nthree dimensional scalar field, which can be switched by a parameter file. HMC\nfor that theory also implemented for comparison. This package has Docker image,\nwhich reduces effort for environment construction. This code works both on CPU\nand NVIDIA GPU.",
        "positive": "Numerical study of the $2+1d$ Thirring model with U($2N$)-invariant\n  fermions: In 2+1 dimensions the global U($2N$) symmetry associated with massless Dirac\nfermions is broken to U($N)\\otimes$U($N$) by a parity-invariant mass. I will\nshow how to adapt the domain wall formulation to recover the U($2N$)-invariant\nlimit in interacting fermion models as the domain wall separation is increased.\nIn particular, I will focus on the issue of potential dynamical mass generation\nin the Thirring model, postulated to take place for $N$ less than some critical\n$N_c$. I will present results of simulations of the model using both HMC\n($N=2$) and RHMC ($N=1$) algorithms, and show that the outcome is very\ndifferent from previous numerical studies of the model made with staggered\nfermions, where the corresponding pattern of symmetry breaking is distinct."
    },
    {
        "anchor": "Bottom-Hadron Mass Splittings from Static-Quark Action on 2+1-Flavor\n  Lattices: We calculate bottom-hadron mass splittings with respect to $B_d$ and\n$\\Lambda_b$ using full QCD with 2+1 flavors of dynamical Kogut-Susskind sea\nquarks and domain-wall valence quarks along with a static heavy quark. Our\nlattices have spatial volume of $(2.5{fm})^3$ with lattice spacing about 0.124\nfm and a range of pion masses as low as 291 MeV. Our results are in agreement\nwith experimental observations and other lattice calculations within our\nstatistical and systematic errors. In particular, we find the mass of the\n$\\Omega_b$ to be consistent with the recent CDF measurement. We also predict\nthe mass for the as yet unobserved $\\Xi^\\prime_b$ to be 5955(27) MeV.",
        "positive": "Large mass hierarchies from strongly-coupled dynamics: Motivated by the absence of signals of new physics at the LHC, which seems to\nimply the presence of large mass hierarchies, we investigate the theoretical\npossibility that these could arise dynamically in new strongly-coupled gauge\ntheories extending the standard model of particle physics. To this purpose, we\nstudy lattice data on non-Abelian gauge theories in the (near-)conformal\nregime---specifically, $\\mathrm{SU}(2)$ with $N_{\\mathrm{f}}=1$ and $2$\ndynamical fermion flavours in the adjoint representation. We focus our\nattention on the ratio $R$ between the masses of the lightest spin-2 and spin-0\nresonances, and draw comparisons with a simple toy model in the context of\ngauge/gravity dualities. For models in which large anomalous dimensions arise\ndynamically, we show indications that this mass ratio can be large, with $R >\n5$. Moreover, our results suggest that $R$ might be related to universal\nproperties of the IR fixed point. Our findings provide an interesting step\ntowards understanding large mass ratios in the non-perturbative regime of\nquantum field theories with (near) IR conformal behaviour."
    },
    {
        "anchor": "The axial charge of the nucleon on the lattice and in chiral\n  perturbation theory: We present recent Monte Carlo data for the axial charge of the nucleon\nobtained by the QCDSF-UKQCD collaboration for N_f=2 dynamical quarks. We\ncompare them with formulae from chiral perturbation theory in finite and\ninfinite volume and find a remarkably consistent picture.",
        "positive": "Chiral Perturbation Theory at Finite Volume and/or with Twisted Boundary\n  Conditions: In this talk we discuss a number of ChPT calculations relevant for lattice\nQCD. These include the finite volume corrections at two-loop order for masses\nand decay constants. The second part is about hadronic vacuum polarization\nwhere we present the two-loop ChPT estimate for the disconnected and strange\nquark contributions. We also present the finite volume corrections at two-loop\norder. The final part is the one-loop finite volume with twisted boundary\nconditions contribution to $f_+(q^2)$ and the full $K_{\\ell3}$ amplitude"
    },
    {
        "anchor": "Improved lattice fermion action for heavy quarks: We develop an improved lattice action for heavy quarks based on\nBrillouin-type fermions, that have excellent energy-momentum dispersion\nrelation. The leading discretization errors of $O(a)$ and $O(a^2)$ are\neliminated at tree-level. We carry out a scaling study of this improved\nBrillouin fermion action on quenched lattices by calculating the charmonium\nenergy-momentum dispersion relation and hyperfine splitting. We present a\ncomparison to standard Wilson fermions and domain-wall fermions.",
        "positive": "Perturbative determination of $c_{SW}$ with Symanzik improved gauge\n  action and stout smearing: We determine the improvement factor $c_{SW}$ in one-loop lattice perturbation\ntheory for the plaquette and Symanzik improved gauge actions. The fermionic\naction is ${\\mathcal{O}(a)}$ clover improved with one-time stout smearing.\n$c_{SW}$ is derived from the one-loop correction to the quark-quark-gluon\nvertex in the off-shell regime. We give a first numerical value for the\none-loop contribution to the non gauge-invariant improvement coefficient\n$c_{NGI}$ for the quark field using the plaquette action. A discussion of mean\nfield improvement is included."
    },
    {
        "anchor": "Full O(a) improvement in EQCD: EQCD is a 3D bosonic theory containing SU(3) and an adjoint scalar, which\nefficiently describes the infrared, nonperturbative sector of hot QCD and which\nis highly amenable to lattice study. We improve the matching between lattice\nand continuum EQCD by determining the final unknown coefficient in the O(a)\nmatching, an additive scalar mass renormalization. We do this numerically by\nusing the symmetry-breaking phase transition point of the theory as a line of\nconstant physics. This prepares the ground for a precision study of the\ntransverse momentum diffusion coefficient C(qperp) within this theory. As a\nbyproduct, we provide an updated version of the EQCD phase diagram.",
        "positive": "New proposal for numerical simulations of theta-vacuum like systems: We propose a new approach to perform numerical simulations of theta-vacuum\nlike systems, test it in two analytically solvable models, and apply it to\nCP^3. The main new ingredient in our approach is the method used to compute the\nprobability distribution function of the topological charge at theta=0. We do\nnot get unphysical phase transitions (flattening behavior of the free energy\ndensity) and reproduce the exact analytical results for the order parameter in\nthe whole theta-range within a few percent."
    },
    {
        "anchor": "Lattice radial quantization by cubature: Basic aspects of a program to put field theories quantized in radial\ncoordinates on the lattice are presented. Only scalar fields are discussed.\nSimple examples are solved to illustrate the strategy when applied to the 3D\nIsing model.",
        "positive": "SU(3) string tension and the presence of vortices: Lattice simulations are presented showing the expectation of the fluctuation\nof the Wilson loop solely by elements of the center to fully reproduce the\nSU(3) heavy quark potential. The results are stable under smoothing, and point\nto thick vortices as being responsible for the full SU(3) tension. An analytic\nresult on the necessary presence of thick vortices for confinement at weak\ncoupling is also presented."
    },
    {
        "anchor": "String breaking by dynamical fermions in three-dimensional lattice QCD: The first observation is made of hadronic string breaking due to dynamical\nfermions in zero temperature lattice QCD. The simulations are done for SU(2)\ncolor in three dimensions, with two flavors of staggered fermions. The results\nhave clear implications for the large scale simulations that are being done to\nsearch (so far, without success) for string breaking in four-dimensional QCD.\nIn particular, string breaking is readily observed using only Wilson loops to\nexcite a static quark-antiquark pair. Improved actions on coarse lattices are\nused, providing an extremely efficient means to access the quark separations\nand propagation times at which string breaking occurs.",
        "positive": "SIMULATeQCD: A simple multi-GPU lattice code for QCD calculations: The rise of exascale supercomputers has fueled competition among GPU vendors,\ndriving lattice QCD developers to write code that supports multiple APIs.\nMoreover, new developments in algorithms and physics research require frequent\nupdates to existing software. These challenges have to be balanced against\nconstantly changing personnel. At the same time, there is a wide range of\napplications for HISQ fermions in QCD studies. This situation encourages the\ndevelopment of software featuring a HISQ action that is flexible,\nhigh-performing, open source, easy to use, and easy to adapt. In this technical\npaper, we explain the design strategy, provide implementation details, list\navailable algorithms and modules, and show key performance indicators for\nSIMULATeQCD, a simple multi-GPU lattice code for large-scale QCD calculations,\nmainly developed and used by the HotQCD collaboration. The code is publicly\navailable on GitHub."
    },
    {
        "anchor": "Finite-size scaling for the left-current correlator with non-degenerate\n  quark masses: We study the volume dependence of the left-current correlator with\nnon-degenerate quark masses to next-to-leading order in the chiral expansion.\nWe consider three possible regimes: all quark masses are in the\n$\\epsilon$-regime, all are in the $p$-regime and a mixed-regime where the\nlighest quark masses satisfy $m_v \\Sigma V \\leq 1$ while the heavier $m_s\n\\Sigma V \\gg 1$. These results can be used to match lattice QCD and the Chiral\nEffective Theory in a large but finite box in which the Compton wavelength of\nthe lightest pions is of the order of the box size. We consider both the full\nand partially-quenched results.",
        "positive": "Moments of GPDs and transverse-momentum dependent PDFs from the lattice: I review lattice-QCD calculations of the electromagnetic and generalized form\nfactors (GFFs), which determine the transverse structure of the nucleon, and\nbriefly comment on recent calculations related to transverse-momentum dependent\nparton distribution functions (TMDPDFs)."
    },
    {
        "anchor": "The Glue Content of the Pion: We perform a quenched computation of the glue momentum fraction in the pion.\nDifferent discretizations of the gluonic energy-momentum tensor are studied on\nthe lattice for that purpose. We discuss some implications based on the\nmomentum sum rule. Finally we point out promising applications of the\ntechniques developed here.",
        "positive": "First-order phase transitions in Yang-Mills theories and the density of\n  state method: When studied at finite temperature, Yang-Mills theories in $3+1$ dimensions\ndisplay the presence of confinement/deconfinement phase transitions, which are\nknown to be of first order -- the $SU(2)$ gauge theory being the exception.\nTheoretical as well as phenomenological considerations indicate that it is\nessential to establish a precise characterisation of these physical systems in\nproximity of such phase transitions. We present and test a new method to study\nthe critical region of parameter space in non-Abelian quantum field theories on\nthe lattice, based upon the Logarithmic Linear Relaxation (LLR) algorithm. We\napply this method to the $SU(3)$ Yang Mills lattice gauge theory, and perform\nextensive calculations with one fixed choice of lattice size. We identify the\ncritical temperature, and measure interesting physical quantities near the\ntransition. Among them, we determine the free energy of the model in the\ncritical region, exposing for the first time its multi-valued nature with a\nnumerical calculation from first principles, providing this novel evidence in\nsupport of a first order phase transition. This study sets the stage for future\nhigh precision measurements, by demonstrating the potential of the method."
    },
    {
        "anchor": "Introducing vortices in the continuum using direct and indirect methods: Inspired by direct and indirect maximal center gauge methods which confirm\nthe existence of vortices in lattice calculations and by using the connection\nformalism, we show that under some appropriate gauge transformations vortices\nand chains appear in the QCD vacuum of the continuum limit. In the direct\nmethod, by applying center gauge transformation and \\textquotedblleft center\nprojection,\\textquotedblright QCD is reduced to a gauge theory including\nvortices, which corresponds to the non-trivial first homotopy group\n$\\Pi_1\\left( \\text{SO}(3)\\right) =Z_2.$ On the other hand, using the indirect\nmethod, in addition to the center gauge transformation and \\textquotedblleft\ncenter projection,\\textquotedblright an initial step called Abelian gauge\ntransformation and then Abelian projection are applied. Therefore, instead of\nsingle vortices, chains that contain monopoles and vortices appear in the\ntheory.",
        "positive": "Current Renormalisation Constants with an O(a)-improved Fermion Action: Using chiral Ward identities, we determine the renormalisation constants of\nbilinear quark operators for the Sheikholeslami-Wohlert action lattice at\nbeta=6.2. The results are obtained with a high degree of accuracy. For the\nvector current renormalisation constant we obtain Z_V=0.817(2)(8), where the\nfirst error is statistical and the second is due to mass dependence of Z_V.\nThis is close to the perturbative value of 0.83. For the axial current\nrenormalisation constant we obtain Z_A = 1.045(+10 -14), significantly higher\nthan the value obtained in perturbation theory. This is shown to reduce the\ndifference between lattice estimates and the experimental values for the\npseudoscalar meson decay constants, but a significant discrepancy remains. The\nratio of pseudoscalar to scalar renormalisation constants, Z_P/Z_S, is less\nwell determined, but seems to be slightly lower than the perturbative value."
    },
    {
        "anchor": "Closed flux tubes in higher representations and their string description\n  in D=2+1 SU(N) gauge theories: We calculate, numerically, the low-lying spectrum of closed confining flux\ntubes that carry flux in different representations of SU(N). We do so for SU(6)\nat beta=171, where the calculated low-energy physics is very close to the\ncontinuum limit and, in many respects, also close to N=infinity. We focus on\nthe adjoint, 84, 120, k=2A,2S and k=3A,3M,3S representations and provide\nevidence that the corresponding flux tubes, albeit mostly unstable, do in fact\nexist. We observe that the ground state of a flux tube with momentum along its\naxis appears to be well defined in all cases and is well described by the\nNambu-Goto free string spectrum, all the way down to very small lengths, just\nas it is for flux tubes carrying fundamental flux. Excited states, however,\ntypically show very much larger deviations from Nambu-Goto than the\ncorresponding excitations of fundamental flux tubes and, indeed, cannot be\nextracted in many cases. We discuss whether what we are seeing here are\nseparate stringy and massive modes or simply large corrections to energy levels\nthat will become string-like at larger lengths.",
        "positive": "Probing Non-perturbative Supersymmetry Breaking through Lattice Path\n  Integrals: We investigate non-perturbative supersymmetry breaking in various models of\nquantum mechanics, including an interesting class of $PT$-invariant models,\nusing lattice path integrals. These theories are discretized on a temporal\nEuclidean lattice with anti-periodic boundary conditions. Hybrid Monte Carlo\nalgorithm is used to update the field configurations to their equilibrium\nvalues. We used the Ward identities and expectation values of superpotentials\nas tools for probing supersymmetry breaking."
    },
    {
        "anchor": "The Shape of Inflated Vesicles: The conformation and scaling properties of self-avoiding fluid vesicles with\nzero extrinsic bending rigidity subject to an internal pressure increment\n$\\Delta p>0$ are studied using Monte Carlo methods and scaling arguments. With\nincreasing pressure, there is a first-order transition from a collapsed\nbranched polymer phase to an extended inflated phase. The scaling behavior of\nthe radius of gyration, the asphericities, and several other quantities\ncharacterizing the average shape of a vesicle are studied in detail. In the\ninflated phase, continuously variable fractal shapes are found to be controlled\nby the scaling variable $x=\\Delta p N^{3\\nu/2}$ (or equivalently, $y = {<V>}/\nN^{3\\nu/2}$), where $N$ is the number of monomers in the vesicle and $V$ the\nenclosed volume. The scaling behavior in the inflated phase is described by a\nnew exponent $\\nu=0.787\\pm 0.02$.",
        "positive": "Phase transitions in the three-dimensional Z(N) models: Phase transitions in zero-temperature 3D Z(N) lattice gauge theories are\nstudied. We use a cluster algorithm defined for the dual formulation of the\nmodels. We also attempt to explain the nature of the intermediate continuously\nsymmetric phase, which appears for N>5. The critical indices are calculated.\nThe results obtained are used to study the scaling of critical points with N,\nas well as the scaling of finite-temperature critical points with the lattice\nsize in the time direction, $N_t$."
    },
    {
        "anchor": "Z(N) dependence of the pure Yang-Mills gluon propagator in the Landau\n  gauge near Tc: The Z(N) dependence of the pure Yang-Mills gluon propagator, in the Landau\ngauge, is investigated at finite temperature for N=3. Special attention will be\ngiven to the behaviour near the critical temperature $T_c$. Our simulations\nshow a complex pattern as expected in a first order phase transition.\nFurthermore, we identify an order parameter directly associated with the\nbreaking of the SU(3) center symmetry.",
        "positive": "Strong coupling constant and heavy quark masses in 2+1 flavor QCD: We present a determination of the strong coupling constant and heavy quark\nmasses in (2+1)-flavor QCD using lattice calculations of the moments of the\npseudo-scalar quarkonium correlators at several values of the heavy valence\nquark mass with Highly Improved Staggered Quark (HISQ) action. We determine the\nstrong coupling constant in the $\\overline{MS}$ scheme at four low-energy\nscales corresponding to $m_c$, $1.5m_c$, $2m_c$, and $3m_c$, with $m_c$ being\nthe charm quark mass. The novel feature of our analysis that up to eleven\nlattice spacings are used in the continuum extrapolations, with the smallest\nlattice spacing being $0.025$ fm. We obtain\n$\\Lambda_{\\overline{MS}}^{n_f=3}=298 \\pm 16$ MeV, which is equivalent to\n$\\alpha_s(\\mu=M_Z,n_f=5)=0.1159(12)$. For the charm and bottom quark masses in\nthe $\\overline{MS}$ scheme, we obtain: $m_c(\\mu=m_c,n_f=4)=1.265(10)$ GeV and\n$m_b(\\mu=m_b,n_f=5)=4.188(37)$ GeV."
    },
    {
        "anchor": "Spectral Analysis of Causal Dynamical Triangulations via Finite Element\n  Method: We examine the dual graph representation of simplicial manifolds in Causal\nDynamical Triangulations (CDT) as a mean to build observables, and propose a\nnew representation based on the Finite Element Methods (FEM). In particular,\nwith the application of FEM techniques, we extract the (low-lying) spectrum of\nthe Laplace-Beltrami (LB) operator on the Sobolev space $H^1$ of scalar\nfunctions on piecewise flat manifolds, and compare them with corresponding\nresults obtained by using the dual graph representation. We show that, besides\nfor non-pathological cases in two dimensions, the dual graph spectrum and\nspectral dimension do not generally agree, neither quantitatively nor\nqualitatively, with the ones obtained from the LB operator on the continuous\nspace. We analyze the reasons of this discrepancy and discuss its possible\nimplications on the definition of generic observables built from the dual graph\nrepresentation.",
        "positive": "Explorations beyond dilaton chiral perturbation theory in the\n  eight-flavor SU(3) gauge theory: We continue our study of spectroscopy data for the SU(3) gauge theory with\neight fundamental fermions, motivated by the effective field theory framework\nof dilaton chiral perturbation theory (dChPT). At leading order dChPT predicts\na constant mass anomalous dimension $\\gamma_m$, consistent with the assumed\nproximity of an infrared fixed point. For the relatively large fermion masses\nsimulated by the LatKMI collaboration, the influence of the infrared fixed\npoint diminishes, and our fits suggest that $\\gamma_m$ starts running. Since a\ncomplete higher-order analysis is not feasible with presently available data,\nwe adopt a more phenomenological approach. We propose a partial extension to\nhigher orders, which incorporates the running of $\\gamma_m$ into the tree-level\nlagrangian. We find that this extension successfully describes the full\nfermion-mass range of the LatKMI data, including the pion taste splittings\nwhich arise from using staggered fermions in the lattice simulations. We also\ninvestigate a more general class of dilaton potentials proposed in the\nliterature, using both the LSD and LatKMI data sets, concluding that these data\nfavor the form predicted by dChPT."
    },
    {
        "anchor": "Finite volume treatment of pi pi scattering and limits to phase shifts\n  extraction from lattice QCD: We study theoretically the effects of finite volume for pipi scattering in\norder to extract physical observables for infinite volume from lattice QCD. We\ncompare three different approaches for pipi scattering (lowest order\nBethe-Salpeter approach, N/D and inverse amplitude methods) with the aim to\nstudy the effects of the finite size of the box in the potential of the\ndifferent theories, specially the left-hand cut contribution through loops in\nthe crossed t,u-channels. We quantify the error made by neglecting these\neffects in usual extractions of physical observables from lattice QCD spectra.\nWe conclude that for pipi phase-shifts in the scalar-isoscalar channel up to\n800 MeV this effect is negligible for box sizes bigger than 2.5m_pi^-1 and of\nthe order of 5% at around 1.5-2m_pi^-1. For isospin 2 the finite size effects\ncan reach up to 10% for that energy. We also quantify the error made when using\nthe standard Luscher method to extract physical observables from lattice QCD,\nwhich is widely used in the literature but is an approximation of the one used\nin the present work.",
        "positive": "SU(2) lattice gauge theory in 2+1 dimensions: critical couplings from\n  twisted boundary conditions and universality: We present a precision determination of the critical coupling beta_c for the\ndeconfinement transition in pure SU(2) gauge theory in 2+1 dimensions. This is\npossible from universality, by intersecting the center vortex free energy as a\nfunction of the lattice coupling beta with the exactly known value of the\ninterface free energy in the 2D Ising model at criticality. Results for\nlattices with different numbers of sites N_t along the Euclidean time direction\nare used to determine how beta varies with temperature for a given N_t around\nthe deconfinement transition."
    },
    {
        "anchor": "The epsilon expansion at next-to-next-to-leading order with small\n  imaginary chemical potential: We discuss chiral perturbation theory for two and three quark flavors in the\nepsilon expansion at next-to-next-to-leading order (NNLO) including a small\nimaginary chemical potential. We calculate finite-volume corrections to the\nlow-energy constants $\\Sigma$ and $F$ and determine the non-universal\nmodifications of the theory, i.e., modifications that cannot be mapped to\nrandom matrix theory (RMT). In the special case of two quark flavors in an\nasymmetric box we discuss how to minimize the finite-volume corrections and\nnon-universal modifications by an optimal choice of the lattice geometry.\nFurthermore we provide a detailed calculation of a special version of the\nmassless sunset diagram at finite volume.",
        "positive": "Nonperturbative tuning of $O(a^2)$ improved staggered fermions: We perform a nonperturbative tuning of the coefficients in the $O(a^2)$\nimproved action for staggered fermions. The mass splitting for the pions of\ndifferent doubler flavor is used as a measure of the symmetry breaking effects\nintroduced by $O(a^2)$ discretization errors. We find that the flavor\nnondegeneracy can be somewhat reduced but not eliminated by such a tuning,\nindicating the need for new terms in the action to reduce the nondegeneracy."
    },
    {
        "anchor": "Taste non-Goldstone pion decay constants in staggered chiral\n  perturbation theory: We calculate the next-to-leading order axial current decay constants of taste\nnon-Goldstone pions and kaons in staggered chiral perturbation theory. This is\nan extension of the taste Goldstone decay constants calculation to that of the\nnon-Goldstone tastes. We present results for the partially quenched case in the\nSU(3) and SU(2) staggered chiral perturbation theories and discuss the\ndifference between the taste Goldstone and non-Goldstone cases.",
        "positive": "Investigation of a Toy Model for Frustration in Abelian Lattice Gauge\n  Theory: We introduce a lattice model with local U(1) gauge symmetry which\nincorporates explicit frustration in d >2. The form of the action is inspired\nfrom the loop expansion of the fermionic determinant in standard lattice QED.\nWe study through numerical simulations the phase diagram of the model,\nrevealing the existence of a frustrated (antiferromagnetic) phase for d=3 and\nd=4, once an appropriate order parameter is identified."
    },
    {
        "anchor": "Charmonium contribution to $B \\rightarrow K\\ell^+\\ell^-: testing the\n  factorization approximation on the lattice: We report the current status of a study of charmonium contribution to $B\n\\rightarrow K\\ell^+\\ell^-$ on the lattice. Our lattice calculation tests the\nfactorization approximation for this contribution. In order to control the\nproblem of the artificial divergence, we focus on the low $q^2$ region with a\nsmall b-quark mass. We also take into account the renormalization constants of\nrelevant four-quark operators calculated through the temporal moments. Results\nsuggest a violation of the factorization approximation.",
        "positive": "\"Light from chaos\" in two dimensions: We perform a Monte-Carlo study of the lattice two-dimensional gauged\nXY-model. Our results confirm the strong-coupling expansion arguments that for\nsufficiently small values of the spin-spin coupling the ``gauge symmetry\nbreaking\" terms decouple and the long-distance physics is that of the unbroken\npure gauge theory. We find no evidence for the existence, conjectured earlier,\nof massless states near a critical value of the spin-spin coupling. We comment\non recent remarks in the literature on the use of gauged XY-models in proposed\nconstructions of chiral lattice gauge theories."
    },
    {
        "anchor": "The flavor dependence of $m_\\varrho / f_\u03c0$: We calculate the $m_\\varrho / f_\\pi$ ratio in the chiral and continuum limit\nfor $SU(3)$ gauge theory coupled to $N_f = 2,3,4,5,6$ fermions in the\nfundamental representation. Keeping all systematic effects under full control\nwe find no statistically significant $N_f$-dependence; $m_\\varrho / f_\\pi =\n7.95(15)$. Assuming the KSRF-relations we conclude that 3 other low energy\nquantities related to the vector meson are also $N_f$-independent within errors\nincluding the $\\varrho\\pi\\pi$ coupling $g_{\\varrho\\pi\\pi}$. If the model is\nthought of as a strong dynamics inspired composite Higgs model our results\nindicate that the experimentally most easily accessible new composite particle,\nthe vector meson, and its properties may be robust and independent of the\nfermion content of the model as long as the gauge group is $SU(3)$, provided\n$N_f$-independence extends all the way to the conformal window.",
        "positive": "Strongly coupled lattice gauge theory with dynamical fermion mass\n  generation in three dimensions: We investigate the critical behaviour of a three-dimensional lattice\n$\\chiU\\phi_3$ model in the chiral limit. The model consists of a staggered\nfermion field, a U(1) gauge field (with coupling parameter $\\beta$) and a\ncomplex scalar field (with hopping parameter $\\kappa$). Two different methods\nare used: 1) fits of the chiral condensate and the mass of the neutral\nunconfined composite fermion to an equation of state and 2) finite size scaling\ninvestigations of the Lee-Yang zeros of the partition function in the complex\nfermion mass plane. For strong gauge coupling ($\\beta < 1$) the critical\nexponents for the chiral phase transition are determined. We find strong\nindications that the chiral phase transition is in one universality class in\nthis $\\beta$ interval: that of the three-dimensional Gross-Neveu model with two\nfermions. Thus the continuum limit of the $\\chiU\\phi_3$ model defines here a\nnonperturbatively renormalizable gauge theory with dynamical mass generation.\nAt weak gauge coupling and small $\\kappa$, we explore a region in which the\nmass in the neutral fermion channel is large but the chiral condensate on\nfinite lattices very small. If it does not vanish in the infinite volume limit,\nthen a continuum limit with massive unconfined fermion might be possible in\nthis region, too."
    },
    {
        "anchor": "Comparison Studies of Finite Momentum Correlators on Anisotropic and\n  Isotropic Lattices: We study hadronic two- and three-point correlators relevant for heavy to\nlight pseudoscalar meson semi-leptonic decays, using Symanzik improved glue,\nD234 light quark and NRQCD heavy quark actions. Detailed comparisons are made\nbetween simulations on anisotropic and isotropic lattices involving finite\nmomentum hadrons. We find evidence that having an anisotropy helps in\nextracting better signals at higher momenta. Initial results for the form\nfactors f_+(q^2) and f_0(q^2) are presented with tree-level matching of the\nlattice heavy-light currents.",
        "positive": "On the spectrum and string tension of U(1) lattice gauge theory in 2+1\n  dimensions: We calculate the low-lying spectra of glueballs and confining flux tubes in\nthe U(1) lattice gauge theory in 2+1 dimensions. We see that up to modest\nlattice spacing corrections, the glueball states are consistent with being\nmultiparticle states composed of non-interacting massive JPC=0-- particles. We\nobserve that the ag^2 -> 0 limit is, as expected, unconventional, and follows\nthe well-known saddle-point analysis of Polyakov to a good approximation. The\nspectrum of closed (winding) flux tubes exhibits the presence of a massive\nworld-sheet excitation whose mass is consistent with that of the bulk screening\nmass. These U(1) calculations are intended to complement existing lattice\ncalculations of the properties of SU(N) and SO(N) gauge theories in D=2+1."
    },
    {
        "anchor": "Multigrid Methods for Propagators in Lattice Gauge Theories: Multigrid methods were invented for the solution of discretized partial\ndifferential equations in ordered systems. The slowness of traditional\nalgorithms is overcome by updates on various length scales. In this article we\ndiscuss generalizations of multigrid methods for disordered systems, in\nparticular for propagators in lattice gauge theories. A discretized nonabelian\ngauge theory can be formulated as a system of statistical mechanics where the\ngauge field degrees of freedom are $SU(N)$ matrices on the links of the\nlattice. These $SU(N)$ matrices appear as random coefficients in Dirac\nequations. We aim at finding an efficient method by which one can solve Dirac\nequations without critical slowing down. If this could be achieved, Monte Carlo\nsimulations of Quantum Chromodynamics (the theory of the strong interaction)\nwould be accelerated considerably. In principle, however, the methods discussed\ncan be used in arbitrary space-time dimension and for arbitrary gauge group.\nMoreover, there are applications in multigrid Monte Carlo simulations, and for\nthe definition of block spins and blocked gauge fields in Monte Carlo\nrenormalization group studies. As a central results it was found that {\\em the\ngeometric multigrid method works in principle in arbitrarily disordered gauge\nfields.} Finally, an overview is given of other approaches to the propagator\nproblem in lattice gauge theories.",
        "positive": "A new class of variance reduction techniques using lattice symmetries: We present a general class of unbiased improved estimators for physical\nobservables in lattice gauge theory computations which significantly reduces\nstatistical errors at modest computational cost. The error reduction\ntechniques, referred to as covariant approximation averaging, utilize\napproximations which are covariant under lattice symmetry transformations. We\nobserved cost reductions from the new method compared to the traditional one,\nfor fixed statistical error, of 16 times for the nucleon mass at $M_\\pi\\sim\n330$ MeV (Domain-Wall quark) and 2.6-20 times for the hadronic vacuum\npolarization at $M_\\pi\\sim 480$ MeV (Asqtad quark). These cost reductions\nshould improve with decreasing quark mass and increasing lattice sizes."
    },
    {
        "anchor": "Finite dt dependence of the Binder cumulants for 3-flavor QCD at finite\n  temperature and isospin density: We simulate 3-flavour lattice QCD at small isospin chemical potential $\\mu_I$\nand finite temperature $T$. At $\\mu_I=0$ there is a critical mass $m_c$ where\nthe finite-temperature transition changes from first order to a crossover. We\nmeasure the $\\mu_I$ dependence of the transition $\\beta$ ($\\beta_c$) for $m$\nclose to $m_c$. $\\beta_c$ and hence $T_c$ decrease slowly with increasing\n$\\mu_I$. $\\beta_c$ at finite $\\mu_I$ is in good agreement $\\beta_c$ at finite\n$\\mu$ (quark-number chemical potential). We use fourth-order Binder cumulants\nto determine the nature of this transition and to search for a critical\nendpoint. We measure the $dt$ dependence of these cumulants and extrapolate to\n$dt=0$. ($dt$ is the `time' increment used in the hybrid molecular-dynamics\nsimulations.) Preliminary measurements of these Binder cumulants show little\n$\\mu_I$ dependence. (Simulations at imaginary $\\mu$ indicate that the $\\mu$\ndependence of the Binder cumulants is also weak.) This contrasts to the $\\mu_I$\ndependence we observed at fixed $dt$.",
        "positive": "Neutral B mixing from 2+1 flavor lattice QCD: We present an update of the Fermilab-MILC Collaboration's calculation of\nhadronic matrix elements for B^0-\\bar{B^0} mixing. This work is a more extended\nanalysis than our recent publication of the SU(3)-breaking ratio xi\n[arXiv:1205.7013]. We use the asqtad staggered action for light valence quarks\nin combination with the Fermilab interpretation of the Sheikoleslami-Wohlert\naction for heavy quarks. The calculations use MILC's 2+1 flavor asqtad\nensembles. Ensembles include four lattice spacings from approximately 0.125 fm\nto 0.045 fm and up/down to strange quark mass ratios as low as 0.05. Our\ncalculation covers the complete set of five operators needed to describe B\nmixing in the Standard Model and beyond. In addition to an update including a\nfuller set of analyzed data, we comment on the form of the staggered ChPT\nextrapolation function."
    },
    {
        "anchor": "Lattice study of infrared behaviour in SU(3) gauge theory with twelve\n  massless flavours: We present details of a lattice study of infrared behaviour in SU(3) gauge\ntheory with twelve massless fermions in the fundamental representation. Using\nthe step-scaling method, we compute the coupling constant in this theory over a\nlarge range of scale. The renormalisation scheme in this work is defined by the\nratio of Polyakov loops in the directions with different boundary conditions.\nWe closely examine systematic effects, and find that they are dominated by\nerrors arising from the continuum extrapolation. Our investigation suggests\nthat SU(3) gauge theory with twelve flavours contains an infrared fixed point.",
        "positive": "Critical behaviour and Scaling functions for the three-dimensional O(6)\n  spin model with external field: We numerically investigate the three-dimensional O(6) model on 12^3 to 120^3\nlattices. From Binder's cumulant at vanishing magnetic field we obtain the\ncritical coupling J_c=1.42865(5) and verify this value with the \\chi^2-method.\nThe universal value of Binder's cumulant at this point is\ng_r(J_c)=-1.94456(10). At the critical coupling we find the critical exponents\n\\nu=0.818(5), \\beta=0.425(2) and \\gamma=1.604(6) from a finite size scaling\nanalysis. We also determine the finite-size-scaling function on the critical\nline and the equation of state. Our O(6)-result for the equation of state is\ncompared to the Ising, O(2) and O(4) results."
    },
    {
        "anchor": "Fermion loop simulations in 2--d lattice theories -- results and\n  limitations: We review our results for the simulation of the 2--d lattice Gross--Neveu\nmodel in a fermion loop representation. Possible extensions of our techniques\nto other models and higher dimensions are discussed, as well as the limitations\nof loop--type representations.",
        "positive": "Control of SU(3) symmetry breaking effects in calculations of B meson\n  decay constant: Early B-physics experiments have left us with a number of puzzles in heavy\nflavour physics. New lattice calculations (with a greater understanding of QCD\neffects in the Standard Model) will be needed to support the increase in\nexperimental precision to be achieved by upcoming experiments such as Belle II.\nWe extend the CSSM/UKQCD/QCDSF studies of SU(3) flavour breaking effects by\npresenting new results for the decay constants $f_B$ and $f_{B_s}$."
    },
    {
        "anchor": "Leibniz rule, locality and supersymmetry on lattice: In a finite volume system, we prove a no-go theorem on a Leibniz rule with a\ncare of locality argument on latttice. The new possibility on the Leibniz rule\nsolutions on lattice is discussed. Although the new solution admits a local\ndifference operator, a non-local product rule is needed. In the case, a\nsupersymmetric interacting theory is simply realized. The difference between\nfinite flavor systems and matrix representations of infinite flavor systems is\nexplained based on a finite volume system analysis including the no-go theorem.",
        "positive": "Hadronic Vacuum Polarization Contribution to g-2 from the Lattice: We give a short description of the present situation of lattice QCD\nsimulations. We then focus on the computation of the anomalous magnetic moment\nof the muon using lattice techniques. We demonstrate that by employing improved\nobservables for the muon anomalous magnetic moment, a significant reduction of\nthe lattice error can be obtained. This provides a promising scenario that the\naccuracy of lattice calculations can match the experimental errors."
    },
    {
        "anchor": "Vortices in SO(3)xZ(2) simulations: We study the configuration space of the Tomboulis $SO(3) \\times Z(2)$\nformulation with periodic boundary conditions. The dynamical variables are\nconstrained by the required coincidence of Z(2) and SO(3) monopoles. We propose\nan update algorithm that satisfies the constraints and is straightforward to\nimplement. We further prove that this it reaches all configurations. We show\nhow the boundary conditions put constraints on the configuration space.\n  We measure gauge invariant vortex counters for \"thin\",\n  \"thick\" and \"hybrid\" vortex sheets. For comparison we also measure projection\nvortex counters defined in the maximal center gauge.",
        "positive": "One loop matching factors for improved staggered four-fermion operators\n  with improved glue: We present results for matching factors for staggered four-fermion operators\nconstructed using HYP-smeared fat links both in the action and the operators.\n  We use perturbation theory to calculate the matching factors and work to\none-loop order. The new feaure of this work is the use of the Symanzik-improved\ngauge action, as opposed to the Wilson gauge action. Our results are needed for\nour ongoing calculation of weak matrix elements using HYP-smeared staggered\nvalence quarks and operators on MILC lattices. We give explicit results for\nmatching factors of the operator needed to calculate $B_K$. We compare the\nimpact of the improvement of the gauge action on one-loop coefficients with\nthat of mean-field improvement of the operators."
    },
    {
        "anchor": "Measuring the Decorrelation Times of Fourier Modes in Simulations: We describe a method to study the rate at which modes decorrelate in\nnumerical simulations. We study the XY model updated with the Metropolis and\nWolff dynamics respectively and compute the rate at which each eigenvector of\nthe dynamics decorrelates. Our method allows us to identify the decorrelation\ntime for each mode separately. We find that the autocorrelation function of the\nvarious modes is markedly different for the `local' Metropolis compared to the\n`non-local' Wolff dynamics. Equipped with this new insight, it may be possible\nto devise highly efficient algorithms.",
        "positive": "Bottomonium and B results from full lattice QCD: We have developed two methods for handling $b$ quarks in lattice QCD. One\nuses NRQCD (now improved to include radiative corrections) and the other uses\nHighly Improved Staggered Quarks (HISQ), extrapolating to the $b$ quark from\nlighter masses and using multiple lattice spacings to control discretisation\nerrors. Comparison of results for the two different methods gives confidence in\nestimates of lattice QCD systematic errors, since they are very different in\nthese two cases. Here we show results for heavyonium hyperfine splittings and\nvector current-current correlator moments using HISQ quarks, to add to earlier\nresults testing the heavy HISQ method with pseudoscalar mesons. We also show\nthe form factor for $B \\rightarrow \\pi l \\nu$ decay at zero recoil using NRQCD\n$b$ quarks and $u/d$ quarks with physical masses. This allows us to test the\nsoft pion theorem relation ($f_0(q^2_{max})=f_B/f_{\\pi}$) accurately and we\nfind good agreement as $M_{\\pi} \\rightarrow 0$. }"
    },
    {
        "anchor": "Confinement: $G_2$ group case: The gauge group being centreless, $G_2$ gauge theory is a good laboratory for\nstudying the role of the centre of the group for colour confinement in\nYang-Mills gauge theories. In this paper, we investigate $G_2$ pure gauge\ntheory at finite temperature on the lattice. By studying the finite size\nscaling of the plaquette, the Polyakov loop and their susceptibilities, we show\nthat a deconfinement phase transition takes place. The analysis of the\npseudocritical exponents give strong evidence of the deconfinement transition\nbeing first order. Implications of our findings for scenarios of colour\nconfinement are discussed.",
        "positive": "Long-distance contributions to flavour-changing processes: Standard lattice calculations in flavour physics or in studies of hadronic\nstructure are based on the evaluation of matrix elements of local composite\noperators between hadronic states or the vacuum. In this talk I discuss\ndevelopments aimed at the computation of long-distance, and hence non-local,\ncontributions to such processes. In particular, I consider the calculation of\nthe $K_L$-$K_S$ mass difference $\\Delta m_K=m_{K_L}-m_{K_S}$ and the amplitude\nfor the rare-kaon decay processes $K\\to\\pi\\ell^+\\ell^-$, where the lepton\n$\\ell=e$ or $\\mu$. Lattice calculations of the long-distance contributions to\nthe indirect $CP$-violating parameter $\\epsilon_K$ and to the rare decays\n$K\\to\\pi\\nu\\bar\\nu$ are also beginning. Finally I discuss the possibility of\nincluding $O(\\alpha)$ electromagnetic effects in computations of leptonic and\nsemileptonic decay widths, where the novel feature is the presence of infrared\ndivergences. This implies that contributions to the width from processes with a\nreal photon in the final state must be combined with those with a virtual\nphoton in the amplitude so that the infrared divergences cancel by the\nBloch-Nordsieck mechanism. I present a proposed procedure for lattice\ncomputations of the $O(\\alpha)$ contributions with control of the cancellation\nof the infrared divergences."
    },
    {
        "anchor": "Exploring Excited Hadrons: Progress in extracting the spectrum of excited hadron resonances is reviewed\nand the key issues and challenges in such computations are outlined. The\nimportance of multi-hadron states as simulations are done with lighter pion\nmasses is discussed, and the need for all-to-all quark propagators is\nemphasized.",
        "positive": "Exploring Topology Conserving Gauge Actions for Lattice QCD: We explore gauge actions for lattice QCD, which are constructed such that the\noccurrence of small plaquette values is strongly suppressed. By choosing strong\nbare gauge couplings we arrive at values for the physical lattice spacings of\nO(0.1 fm). Such gauge actions tend to confine the Monte Carlo history to a\nsingle topological sector. This topological stability facilitates the\ncollection of a large set of configurations in a specific sector, which is\nprofitable for numerical studies in the epsilon-regime. The suppression of\nsmall plaquette values is also expected to be favourable for simulations with\ndynamical quarks. We use a local Hybrid Monte Carlo algorithm to simulate such\nactions, and we present numerical results for the static potential, the\nphysical scale, the topological stability and the kernel condition number of\nthe overlap Dirac operator. In addition we discuss the question of reflection\npositivity for a class of such gauge actions."
    },
    {
        "anchor": "$B_K$ using HYP-smeared staggered fermions in $N_f=2+1$ unquenched QCD: We present results for kaon mixing parameter $B_K$ calculated using\nHYP-smeared improved staggered fermions on the MILC asqtad lattices. We use\nthree lattice spacings ($a\\approx 0.12$, $0.09$ and $0.06\\;$fm), ten different\nvalence quark masses ($m\\approx m_s/10-m_s$), and several light sea-quark\nmasses in order to control the continuum and chiral extrapolations. We derive\nthe next-to-leading order staggered chiral perturbation theory (SChPT) results\nnecessary to fit our data, and use these results to do extrapolations based\nboth on SU(2) and SU(3) SChPT. The SU(2) fitting is particularly\nstraightforward because parameters related to taste-breaking and matching\nerrors appear only at next-to-next-to-leading order. We match to the continuum\nrenormalization scheme (NDR) using one-loop perturbation theory. Our final\nresult is from the SU(2) analysis, with the SU(3) result providing a (less\naccurate) cross check. We find $B_K(\\text{NDR}, \\mu = 2 \\text{GeV}) = 0.529 \\pm\n0.009 \\pm 0.032$ and $\\hat{B}_K =B_K(\\text{RGI})= 0.724 \\pm 0.012 \\pm 0.043$,\nwhere the first error is statistical and the second systematic. The error is\ndominated by the truncation error in the matching factor. Our results are\nconsistent with those obtained using valence domain-wall fermions on lattices\ngenerated with asqtad or domain-wall sea quarks.",
        "positive": "Transfer matrices and temporal factorization of the Wilson fermion\n  determinant: When lattice QCD is formulated in sectors of fixed quark numbers, the\ncanonical fermion determinants can be expressed explicitly in terms of transfer\nmatrices. This in turn provides a complete factorization of the fermion\ndeterminants in temporal direction. Here we present a generic overview of this\nfactorization, apply it to Wilson-type fermions and provide explicit\nconstructions of the transfer matrices. Possible applications of the\nfactorization include multi-level integration schemes and the construction of\nimproved estimators for generic $n$-point correlation functions."
    },
    {
        "anchor": "Charmonium properties in deconfinement phase in anisotropic lattice QCD: J/Psi and eta_c above the QCD critical temperature T_c are studied in\nanisotropic quenched lattice QCD, considering whether the c\\bar c systems above\nT_c are spatially compact (quasi-)bound states or scattering states. We adopt\nthe standard Wilson gauge action and O(a)-improved Wilson quark action with\nrenormalized anisotropy a_s/a_t =4.0 at \\beta=6.10 on 16^3\\times (14-26)\nlattices, which correspond to the spatial lattice volume V\\equiv\nL^3\\simeq(1.55{\\rm fm})^3 and temperatures T\\simeq(1.11-2.07)T_c. We\ninvestigate the c\\bar c system above T_c from the temporal correlators with\nspatially-extended operators, where the overlap with the ground state is\nenhanced. To clarify whether compact charmonia survive in the deconfinement\nphase, we investigate spatial boundary-condition dependence of the energy of\nc\\bar c systems above T_c. In fact, for low-lying S-wave c \\bar c scattering\nstates, it is expected that there appears a significant energy difference\n\\Delta E \\equiv E{\\rm (APBC)}-E{\\rm (PBC)}\\simeq2\\sqrt{m_c^2+3\\pi^2/L^2}-2m_c\n(m_c: charm quark mass) between periodic and anti-periodic boundary conditions\non the finite-volume lattice. In contrast, for compact charmonia, there is no\nsignificant energy difference between periodic and anti-periodic boundary\nconditions. As a lattice QCD result, almost no spatial boundary-condition\ndependence is observed for the energy of the c\\bar c system in J/\\Psi and\n\\eta_c channels for T\\simeq(1.11-2.07)T_c. This fact indicates that J/\\Psi and\n\\eta_c would survive as spatially compact c\\bar c (quasi-)bound states below\n2T_c. We also investigate a $P$-wave channel at high temperature with maximally\nentropy method (MEM) and find no low-lying peak structure corresponding to\n\\chi_{c1} at 1.62T_c.",
        "positive": "The Renormalization Group and Dynamical Triangulations: A block spin renormalization group approach is introduced which can be\napplied to dynamical triangulations in any dimension."
    },
    {
        "anchor": "Towards Radiative Transitions in Charmonium: We present preliminary calculations towards radiative transitions in\ncharmonium using anisotropic $N_f = 2 + 1$ dynamical ensembles generated by the\nHadron Spectrum Collaboration. With the use of newer technologies we aim to\ninvestigate transitions between states, including potential exotic charmonium\nstates, lying higher in the spectrum than in previous studies. A crucial\ningredient in this work is the use of variationally optimised interpolating\noperators which allow for a reliable determination of the three-point\ncorrelation functions needed. Using these operators, we perform first\ncalculations of relevant three-point correlation functions before discussing\nfuture directions.",
        "positive": "Abelian chromomagnetic fields and confinement: We study vacuum dynamics of SU(3) lattice gauge theory at finite temperature\nusing the lattice Schr\\\"odinger functional. The SU(3) vacuum is probed by means\nof an external constant Abelian chromomagnetic field. We find that by\nincreasing the strength of the applied external field the deconfinement\ntemperature decreases towards zero. This means that strong enough Abelian\nchromomagnetic fields destroy confinement of color. We discuss some\nconsequences of this phenomenon on confinement and quark stars."
    },
    {
        "anchor": "Perturbative Subtraction Methods: The effects of an automated, tenth order in $\\kappa$ subtraction scheme on\nthe noise variance of various Wilson QCD disconnected matrix elements are\nexamined. It is found that there is a dramatic reduction in the variance of the\nlattice point-split electromagnetic currents and that this reduction persists\nat small quark mass.",
        "positive": "Multi-Grid Lanczos: We present a Lanczos algorithm utilizing multiple grids that reduces the\nmemory requirements both on disk and in working memory by one order of\nmagnitude for RBC/UKQCD's 48I and 64I ensembles at the physical pion mass. The\nprecision of the resulting eigenvectors is on par with exact deflation."
    },
    {
        "anchor": "Nonperturbatively Improved Hadron Spectroscopy Near the Continuum Limit: We report the results of our quenched lattice simulations of the Wilson\naction with a nonperturbatively determined clover term at beta=6.2 and compare\nthem with those of the standard Wilson action at the same beta value.",
        "positive": "Hyperon single-particle potentials from QCD on lattice: We study single-particle potential of hyperons in nuclear medium starting\nfrom QCD. First we carry out lattice QCD numerical simulation to extract\nbaryon-baryon interactions from QCD by means of the HAL QCD method. We employ a\nfull QCD gauge configuration ensemble at almost physical point so that hadron\nmasses are nearly physical, e.g. pion mass is 146 MeV, kaon mass is 525 MeV,\nand nucleon mass is 956 MeV. Then, with some simplifications, we apply the\nobtained hyperon interactions to the Brueckner-Hartree-Fock theory and\ncalculate single-particle potential of hyperons in nuclear medium\n$U_{Y}(\\rho,k)$. For the symmetric nuclear matter at the normal nuclear matter\ndensity, we obtain $U_{\\Lambda}(\\rho_0,0)=-33$ MeV, $U_{\\Sigma}(\\rho_0,0)=+11$\nMeV, and $U_{\\Xi}(\\rho_0,0)=-6$ MeV. These results are qualitatively compatible\nwith values suggested from experiments. This success is remarkable and\nencouraging because we are trying to reveal nature of baryon-baryon\ninteractions starting from QCD, and this agreement proves that our approach is\nessentially correct."
    },
    {
        "anchor": "The structure of the gluon propagator: The gluon propagator has been calculated for quenched QCD in the Landau gauge\nat beta=6.0 for volumes 16^3x48 and 32^3x64, and at beta=6.2 for volume\n24^3x48$. The large volume and different lattice spacings allow us to identify\nand minimise finite volume and finite lattice spacing artefacts. We also study\nthe tensor structure of the gluon propagator, confirming that it obeys the\nlattice Landau gauge condition.",
        "positive": "Upper and lower Higgs boson mass bounds from a chirally invariant\n  lattice Higgs-Yukawa model: Motivated by the advent of the Large Hadron Collider the aim of the present\nwork is the non-perturbative determination of the cutoff-dependent upper and\nlower mass bounds of the Standard Model Higgs boson based on first principle\ncalculations, in particular not relying on additional information such as the\ntriviality property of the Higgs-Yukawa sector or indirect arguments like\nvacuum stability considerations. For that purpose the lattice approach is\nemployed to allow for a non-perturbative investigation of a chirally invariant\nlattice Higgs-Yukawa model, serving here as a reasonable simplification of the\nfull Standard Model, containing only those fields and interactions which are\nmost essential for the intended Higgs boson mass determination. These are the\ncomplex Higgs doublet as well as the top and bottom quark fields and their\nmutual interactions. To maintain the chiral character of the Standard Model\nHiggs-fermion coupling also on the lattice, the latter model is constructed on\nthe basis of the Neuberger overlap operator, obeying then an exact global\nlattice chiral symmetry."
    },
    {
        "anchor": "Lattice QCD study of baryon-baryon interactions in the (S,I)=(-2,0)\n  system using the coupled-channel formalism: We investigate baryon-baryon interactions with strangeness $S=-2$ and isospin\nI=0 system from Lattice QCD. In order to solve this system, we prepare three\ntypes of baryon-baryon operators ($\\Lambda-\\Lambda$, $N-\\Xi$ and\n$\\Sigma-\\Sigma$) for the sink and construct three source operators\ndiagonalizing the $3\\times3$ correlation matrix. Combining of the prepared sink\noperators with the diagonalized source operators, we obtain nine effective\nNambu-Bethe-Salpeter (NBS) wave functions. The $3\\times3$ potential matrix is\ncalculated by solving the coupled-channel Schr\\\"odinger equation. The flavor\nSU(3) breaking effects of the potential matrix are also discussed by comparing\nwith the results of the SU(3) limit calculation. Our numerical results are\nobtained from three sets of 2+1 flavor QCD gauge configurations provided by the\nCP-PACS/JLQCD Collaborations.",
        "positive": "Renormalization constants of local operators for Wilson type improved\n  fermions: Perturbative and non-perturbative results are presented on the\nrenormalization constants of the quark field and the vector, axial-vector,\npseudoscalar, scalar and tensor currents. The perturbative computation, carried\nout at one-loop level and up to second order in the lattice spacing, is\nperformed for a fermion action, which includes the clover term and the twisted\nmass parameter yielding results that are applicable for unimproved Wilson\nfermions, as well as for improved clover and twisted mass fermions. We consider\nten variants of the Symanzik improved gauge action corresponding to ten\ndifferent values of the plaquette coefficients. Non-perturbative results are\nobtained using the twisted mass Wilson fermion formulation employing two\ndegenerate dynamical quarks and the tree-level Symanzik improved gluon action.\nThe simulations are performed for pion masses in the range of 480 MeV to 260\nMeV and at three values of the lattice spacing, a, corresponding to beta=3.9,\n4.05, 4.20. For each renormalization factor computed non-perturbatively we\nsubtract its perturbative O(a^2) terms so that we eliminate part of the cut-off\nartifacts. The renormalization constants are converted to MS-bar at a scale of\nmu=2 GeV. The perturbative results depend on a large number of parameters and\nare made easily accessible to the reader by including them in the distribution\npackage of this paper, as a Mathematica input file."
    },
    {
        "anchor": "Toward a well defined monopole creation operator: The lattice implementation of monopole creation operator proves to have\nproblems related to bulk transitions that can possibly affect the\ninterpretation of its mean value as an order parameter for monopole\ncondensation. Preliminary evidence is presented that these unexpected\nbehaviours are in fact only due to lattice artefacts and do not spoil the\nphysical interpretation of the monopole operator.",
        "positive": "The Quark-Gluon Mixed Condensate g<\\bar{q} sigma G q> in SU(3)c Quenched\n  Lattice QCD: Using the SU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched\nlevel, we study the quark-gluon mixed condensate g<\\bar{q} sigma G q>, which is\nanother chiral order parameter. For each current quark mass of m_q=21, 36, 52\nMeV, we generate 100 gauge configurations in the 16^4 lattice with \\beta = 6.0,\nand perform the measurement of the mixed condensate at 16 points in each gauge\nconfiguration. Using the 1600 data for each m_q, we find the ratio between the\nmixed condensate and the quark condensate, m_0^2 = g<\\bar{q} sigma G q>/\n<\\bar{q}q> \\simeq 2.5 GeV^2 at the lattice scale in the chiral limit. The large\nvalue of the mixed condensate suggests its importance in the operator product\nexpansion in QCD."
    },
    {
        "anchor": "f(2010) in Lattice QCD: We present a search for the possible $I(J^{P})=0(2^{+})$ tetraquark state\nwith $ss{\\bar s}{\\bar s}$ quark content in quenched improved anisotropic\nlattice QCD. Using various local and non-local interpolating fields we\ndetermine the energies of ground-state and second ground state using\nvariational method. The state is found to be consistent with two-particle\nscattering state, which is checked to exhibit the expected volume dependence of\nthe spectral weights. In the physical limit, we obtain for the ground state, a\nmass of $2123(33)(58)$ MeV which is higher than the mass of experimentally\nobserved $f(2010)$. The lattice resonance signal obtained in the physical\nregion does not support a localized $J^{P} =2^{+}$ tetraquark state in the pion\nmass region of $300 - 800$ MeV. We conclude that the $4q$ system in question\nappears as a two-particle scattering state in the quark mass region explored\nhere.",
        "positive": "Finetuning the continuum limit in low-dimensional supersymmetric\n  theories: Supersymmetry is a prominent candidate for physics beyond the standard model.\nIn order to compute the spectrum of supersymmetric theories, we employ\nnonperturbative lattice QFT techniques which due to the discretisation of\nspacetime violate supersymmetry at finite lattice spacings. Care has to be\ntaken then to restore supersymmetry in the continuum limit. We discuss a\ndiscretisation of the supersymmetric Nonlinear O(N) Sigma model in two\ndimensions and argue that supersymmetry may be restored by finetuning of a\nsingle parameter. Furthermore, we show preliminary results for the vacuum\nphysics of N = 2 Super-Yang-Mills theory in three dimensions."
    },
    {
        "anchor": "Lattice sum rules for the colour fields: We analyse the sum rules describing the action and energy in the colour\nfields around glueballs, torelons and static potentials.",
        "positive": "Bottomonium resonances with $I = 0$ from lattice QCD correlation\n  functions with static and light quarks: We discuss, how to study $I = 0$ quarkonium resonances decaying into pairs of\nheavy-light mesons using static potentials from lattice QCD. These static\npotentials can be obtained from a set of correlation functions containing both\nstatic and light quarks. As a proof of concept we focus on bottomonium with\nrelative orbital angular momentum $L = 0$ of the $\\bar{b} b$ pair corresponding\nto $J^{P C} = 0^{- +}$ and $J^{P C} = 1^{- -}$. We use static potentials from\nan existing lattice QCD string breaking study and compute phase shifts and\n$\\mbox{T}$ matrix poles for the lightest heavy-light meson-meson decay channel.\nWe discuss our results in the context of corresponding experimental results, in\nparticular for $\\Upsilon (10860)$ and $\\Upsilon (11020)$."
    },
    {
        "anchor": "Higgs-Yukawa model with higher dimension operators via extended mean\n  field theory: Using extended mean field theory (EMFT) on the lattice, we study properties\nof the Higgs-Yukawa model as an approximation of the standard model Higgs\nsector, and the effect of higher dimension operators. We note that the\ndiscussion of vacuum stability is completely modified in the presence of a\n$\\phi^6$ term, and that the Higgs mass no longer appears fine tuned. We also\nstudy the finite temperature transition. Without higher dimension operators the\ntransition is found to be second order (crossover with gauge fields) for the\nexperimental value of the Higgs mass $M_h=125$ GeV. By taking a $\\phi^6$\ninteraction in the Higgs potential as a proxy for a UV completion of the\nstandard model, the transition becomes stronger and turns first order if the\nscale of new physics, i.e. the mass of the lightest mediator particle, is\naround $1.5$ TeV. This implies that electroweak baryogenesis may be viable in\nmodels which introduce new particles around that scale.",
        "positive": "Remarks on the Gauge Dependence of the RI/MOM Renormalization Procedure: The RI/MOM non-perturbative renormalization scheme is studied on the lattice\nin SU(3) quenched QCD with Wilson fermions. The gauge dependence of some\nfermion bilinear renormalization constants is discussed by comparing data which\nhave been gauge-fixed in two different realizations of the Landau gauge and in\na generic covariant gauge. The very good agreement between the various sets of\nresults and the theory indicates that the numerical uncertainty induced by the\nlattice gauge-fixing procedure is moderate and below the statistical errors."
    },
    {
        "anchor": "Lattice QCD equation of state at finite chemical potential from an\n  alternative expansion scheme: Taylor expansion of the equation of state of QCD suffers from shortcomings at\nchemical potentials $\\mu_B \\geq (2-2.5)T$. First, one faces difficulties\ninherent in performing such an expansion with a limited number of coefficients;\nsecond, higher order coefficients determined from lattice calculations suffer\nfrom a poor signal-to-noise ratio. In this work, we present a novel scheme for\nextrapolating the equation of state of QCD to finite, real chemical potential\nthat can extend its reach further than previous methods. We present continuum\nextrapolated lattice results for the new expansion coefficients and show the\nthermodynamic observables up to $\\mu_B/T\\le3.5$.",
        "positive": "Kaon Matrix Elements and CP-violation from Quenched Lattice QCD: (I) the\n  3-flavor case: We report the results of a calculation of the K --> pi pi matrix elements\nrelevant for the $\\DIhalf$ rule and $\\epe$ in quenched lattice QCD using domain\nwall fermions at a fixed lattice spacing $a^{-1} \\sim 2$ GeV. Working in the\nthree-quark effective theory, where only the u, d and s quarks enter and which\nis known perturbatively to next-to-leading order, we calculate the lattice K\n--> pi and K --> |0> matrix elements of dimension six, four-fermion operators.\nThrough lowest order chiral perturbation theory these yield K --> pi pi matrix\nelements, which we then normalize to continuum values through a\nnon-perturbative renormalization technique. For the ratio of isospin amplitudes\n|A_0|/|A_2| we find a value of $25.3 \\pm 1.8$ (statistical error only) compared\nto the experimental value of 22.2, with individual isospin amplitudes 10-20%\nbelow the experimental values. For $\\epe$, using known central values for\nstandard model parameters, we calculate $(-4.0 \\pm 2.3) \\times 10^{-4}$\n(statistical error only) compared to the current experimental average of $(17.2\n\\pm 1.8) \\times 10^{-4}$. Because we find a large cancellation between the I =\n0 and I = 2 contributions to $\\epe$, the result may be very sensitive to the\napproximations employed. Among these are the use of: quenched QCD, lowest order\nchiral perturbation theory and continuum perturbation theory below 1.3 GeV. We\nhave also calculated the kaon B parameter, B_K and find $B_{K,\\bar{MS}}(2 {\\rm\nGeV}) = 0.532(11)$. Although currently unable to give a reliable systematic\nerror, we have control over statistical errors and more simulations will yield\ninformation about the effects of the approximations on this first-principles\ndetermination of these important quantities."
    },
    {
        "anchor": "Towards the P-wave nucleon-pion scattering amplitude in the $\u0394\n  (1232)$ channel: We use lattice QCD and the L\\\"uscher method to study elastic pion-nucleon\nscattering in the isospin $I = 3/2$ channel, which couples to the\n$\\Delta(1232)$ resonance. Our $N_f=2+1$ flavor lattice setup features a pion\nmass of $m_\\pi \\approx 250$ MeV, such that the strong decay channel $\\Delta\n\\rightarrow \\pi N$ is close to the threshold. We present our method for\nconstructing the required lattice correlation functions from single- and\ntwo-hadron interpolating fields and their projection to irreducible\nrepresentations of the relevant symmetry group of the lattice. We show\npreliminary results for the energy spectra in selected moving frames and\nirreducible representations, and extract the scattering phase shifts. Using a\nBreit-Wigner fit, we also determine the resonance mass $m_\\Delta$ and the\n$g_{\\Delta-\\pi N}$ coupling.",
        "positive": "The calculation of nucleon strangeness form factors from N_f=2+1 clover\n  fermion lattice QCD: We study the strangeness electromagnetic form factors of the nucleon from the\nN_f=2+1 clover fermion lattice QCD calculation. The disconnected insertions are\nevaluated using the Z(4) stochastic method, along with unbiased subtractions\nfrom the hopping parameter expansion. In addition to increasing the number of\nZ(4) noises, we find that increasing the number of nucleon sources for each\nconfiguration improves the signal significantly. We obtain G_M^s(0) =\n-0.017(25)(07), where the first error is statistical, and the second is the\nuncertainties in Q^2 and chiral extrapolations. This is consistent with\nexperimental values, and has an order of magnitude smaller error. We also study\nthe strangeness second moment of the partion distribution function of the\nnucleon, <x^2>_{s-\\bar{s}}."
    },
    {
        "anchor": "The one-loop analysis of the beta-function in the Schroedinger\n  Functional for Moebius Domain Wall Fermions: We proposed a construction of the Schroedinger functional scheme for the\nMoebius domain wall fermions (MDWF) by introducing a proper boundary operator\nto the original MDWF in the last conference. The spectrum of the effective\nfour-dimensional operator was investigated. This year we investigate the\nfermionic contribution to the beta-function with the Moebius domain wall\nfermion with the SF boundary term up to the one-loop level and find that our\nconstruction properly reproduce the one-loop beta-function.",
        "positive": "Two-loop renormalization of scalar and pseudoscalar fermion bilinears on\n  the lattice: We compute the two-loop renormalization functions, in the RI $^\\prime$\nscheme, of local bilinear quark operators $\\bar{\\psi}\\Gamma\\psi$, where\n$\\Gamma$ denotes the Scalar and Pseudoscalar Dirac matrices, in the lattice\nformulation of QCD. We consider both the flavor non-singlet and singlet\noperators; the latter, in the scalar case, leads directly to the two-loop\nfermion mass renormalization, $Z_m$.\n  As a prerequisite for the above, we also compute the quark field\nrenormalization, $Z_{\\psi}$, up to two loops.\n  We use the clover action for fermions and the Wilson action for gluons. Our\nresults are given as a polynomial in $c_{SW}$, in terms of both the\nrenormalized and bare coupling constant, in the renormalized Feynman gauge. We\nalso confirm the 1-loop renormalization functions, for generic gauge.\n  Finally, we present our results in the $\\bar{MS}$ scheme, for easier\ncomparison with calculations in the continuum.\n  The corresponding results, for fermions in an arbitrary representation, are\nincluded in an Appendix."
    },
    {
        "anchor": "Study of the conformal hyperscaling relation through the Schwinger-Dyson\n  equation: We study corrections to the conformal hyperscaling relation in the conformal\nwindow of the large Nf QCD by using the ladder Schwinger-Dyson (SD) equation as\na concrete dynamical model. From the analytical expression of the solution of\nthe ladder SD equation, we identify the form of the leading mass correction to\nthe hyperscaling relation. We find that the anomalous dimension, when\nidentified through the hyperscaling relation neglecting these corrections,\nyields a value substantially lower than the one at the fixed point \\gamma_m^*\nfor large mass region. We further study finite-volume effects on the\nhyperscaling relation, based on the ladder SD equation in a finite space-time\nwith the periodic boundary condition. We find that the finite-volume\ncorrections on the hyperscaling relation are negligible compared with the mass\ncorrection. The anomalous dimension, when identified through the finite-size\nhyperscaling relation neglecting the mass corrections as is often done in the\nlattice analyses, yields almost the same value as that in the case of the\ninfinite space-time neglecting the mass correction, i.e., a substantially lower\nvalue than \\gamma_m^* for large mass. We also apply the finite-volume SD\nequation to the chiral-symmetry-breaking phase and find that when the theory is\nclose to the critical point such that the dynamically generated mass is much\nsmaller than the explicit breaking mass, the finite-size hyperscaling relation\nis still operative. We also suggest a concrete form of the modification of the\nfinite-size hyperscaling relation by including the mass correction, which may\nbe useful to analyze the lattice data.",
        "positive": "Lattice chirality, anomaly matching, and more on the (non)decoupling of\n  mirror fermions: We study 't Hooft anomaly matching in lattice models with strong Yukawa or\nmulti-fermion interactions. Strong non-gauge interactions among the mirror\nfermions in a vectorlike lattice gauge theory are introduced with the aim to\nobtain, in a strong-coupling symmetric phase, a long-distance unbroken gauge\ntheory with chiral fermions in a complex representation. We show how to use\nexact lattice chirality to analyze the anomaly matching conditions on chiral\nsymmetry current correlators at finite lattice spacing and volume. We perform a\nMonte Carlo study of the realization of anomaly matching in a toy\ntwo-dimensional model with an anomalous mirror-fermion content at strong mirror\nYukawa coupling. We show that 't Hooft anomaly matching is satisfied, in most\nof the phase diagram, via the minimal solution in either the massless fermion\nor \"Goldstone\" mode, while in some cases there are extra massless vectorlike\nmirror fermions. The mirror spectrum at strong coupling is thus consistent with\nlong-distance unitarity. We discuss the implications of our results for future\nstudies of the most interesting case of the decoupling of anomaly-free\nmirror-fermion sectors."
    },
    {
        "anchor": "Impact of centre vortex removal on the Landau-gauge quark propagator in\n  dynamical QCD: The important role of centre vortices in dynamical chiral symmetry breaking\nand corresponding dynamical mass generation has been demonstrated in pure gauge\nstudies of the Landau-gauge quark propagator. We present initial results of our\ninvestigation into the impact of centre vortex removal on the Landau-gauge\npropagator on dynamical gauge fields. To ensure sensitivity to the topology of\nthe gauge fields, the propagator is computed with overlap fermions. Upon\nremoval of centre vortices we find that dynamical mass generation is\nsuppressed. The quark renormalisation function remains remarkably flat except\nin the deep infrared where it exhibits significant suppression. These effects\nbecome more prominent at lighter quark masses.",
        "positive": "Automatic generation of Feynman rules in the Schroedinger functional: We provide an algorithm to generate vertices for the Schr\\\"odinger functional\nwith an abelian background gauge field. The background field has a non-trivial\ncolor structure, therefore we mainly focus on a manipulation of the color\nmatrix part. We propose how to implement the algorithm especially in python\ncode. By using python outputs produced by the code, we also show how to write a\nnumerical expression of vertices in the time-momentum as well as the coordinate\nspace into a Feynman diagram calculation code. As examples of the applications\nof the algorithm, we provide some one-loop results, ratios of the Lambda\nparameters between the plaquette gauge action and the improved gauge actions\ncomposed from six-link loops (rectangular, chair and parallelogram), the\ndetermination of the O(a) boundary counter term to this order, and the\nperturbative cutoff effects of the step scaling function of the Schroedinger\nfunctional coupling constant."
    },
    {
        "anchor": "String-net formulation of Hamiltonian lattice Yang-Mills theories and\n  quantum many-body scars in a nonabelian gauge theory: We study the Hamiltonian lattice Yang-Mills theory based on spin networks\nthat provide a useful basis to represent the physical states satisfying the\nGauss law constraints. We focus on $\\mathrm{SU}(2)$ Yang-Mills theory in\n$(2+1)$ dimensions. Following the string-net model, we introduce a\nregularization of the Kogut-Susskind Hamiltonian of lattice Yang-Mills theory\nbased on the $q$ deformation, which respects the (discretized) $\\mathrm{SU}(2)$\ngauge symmetry as quantum group, i.e., $\\mathrm{SU}(2)_k$, and enables\nimplementation of the lattice Yang-Mills theory both in classical and quantum\nalgorithms by referring to those of the string-net model. Using the regularized\nHamiltonian, we study quantum scars in a nonabelian gauge theory. Quantum scars\nare nonthermal energy eigenstates arising in the constrained quantum many-body\nsystems. We find that quantum scars from zero modes, which have been found in\nabelian gauge theories arise even in a nonabelian gauge theory. We also show\nthe spectrum of a single-plaquette model for SU(2)$_k$ and SU(3)$_k$ with naive\ncutoff and that based on the $q$-deformation to discuss cutoff dependence of\nthe formulation.",
        "positive": "New lessons from the nucleon mass, lattice QCD and heavy baryon chiral\n  perturbation theory: I will review heavy baryon chiral perturbation theory for the nucleon delta\ndegrees of freedom and then examine the recent dynamical lattice calculations\nof the nucleon mass from the BMW, ETM, JLQCD, LHP, MILC, NPLQCD, PACS-CS,\nQCDSF/UKQCD and RBC/UKQCD Collaborations. Performing the chiral extrapolations\nof these results, one finds remarkable agreement with the physical nucleon\nmass, from each lattice data set. However, a careful examination of the lattice\ndata and the resulting extrapolation functions reveals some unexpected results,\nserving to highlight the significant challenges in performing chiral\nextrapolations of baryon quantities. All the N_f=2+1 dynamical results can be\nquantitatively described by theoretically unmotivated fit function linear in\nthe pion mass with m_pi ~ 750 -190 MeV. When extrapolated to the physical\npoint, the results are in striking agreement with the physical nucleon mass. I\nwill argue that knowledge of each lattice datum of the nucleon mass is required\nat the 1-2% level, including all systematics, in order to conclusively\ndetermine if this is a bizarre conspiracy of lattice artifacts or rather a\nmysterious phenomenon of QCD."
    },
    {
        "anchor": "Compact lattice formulation of Cho-Faddeev-Niemi decomposition: string\n  tension from magnetic monopoles: In this paper we begin on a new lattice formulation of the non-linear change\nof variables called the Cho--Faddeev--Niemi decomposition in SU(2) Yang-Mills\ntheory. This is a compact lattice formulation improving the non-compact lattice\nformulation proposed in our previous paper. Based on this formulation, we\npropose a new gauge-invariant definition of the magnetic monopole current which\nguarantees the magnetic charge quantization and reproduces the conventional\nmagnetic-current density obtained in the Abelian projection based on the\nDeGrand--Toussaint method. Finally, we demonstrate the magnetic monopole\ndominance in the string tension in SU(2) Yang-Mills theory on a lattice. Our\nformulation enables one to reproduce in the gauge-invariant way remarkable\nresults obtained so far only in the Maximally Abelian gauge.",
        "positive": "Measuring of chiral susceptibility using gradient flow: In lattice QCD with Wilson-type quarks, the chiral symmetry is explicitly\nbroken by the Wilson term on finite lattices. Though the symmetry is guaranteed\nto recover in the continuum limit, a series of non-trivial procedures are\nrequired to recover the correct renormalized theory in the continuum limit.\nRecently, a new use of the gradient flow technique was proposed, in which\ncorrectly renormalized quantities are evaluated in the vanishing flow-time\nlimit. This enables us to directly study the chiral condensate and its\nsusceptibility with Wilson-type quarks. Extending our previous study of the\nchiral condensate and its disconnected susceptibility in (2+1)-flavor QCD at a\nheavy $u$, $d$ quark mass ($m_{\\pi}/m_{\\rho}\\simeq0.63$) and approximately\nphysical $s$ quark mass, we compute the connected contributions to the chiral\nsusceptibility in the temperature range of 178--348 MeV on a fine lattice with\n$a\\simeq0.07$ fm."
    },
    {
        "anchor": "Improvement of algorithms for dynamical overlap fermions: We investigate the algorithms for dynamical overlap fermions aiming at\nimproving the performance for large-scale simulations. We look for the best\ncombination of Hybrid Monte Carlo options and iterative quark solvers with\nrespect to the numerical costs. Our main target is a $N_f=2$ simulation with\noverlap fermion on a $16^3\\times 32$ lattice at lattice spacing around 0.12 fm.",
        "positive": "Hadronic Spectral Functions in Lattice QCD: QCD spectral functions of hadrons in the pseudo-scalar and vector channels\nare extracted from lattice Monte Carlo data of the imaginary time Green's\nfunctions. The maximum entropy method works well for this purpose, and the\nresonance and continuum structures in the spectra are obtained in addition to\nthe ground state peaks."
    },
    {
        "anchor": "Weak decay of magnetized pions: The leptonic decay of charged pions is investigated in the presence of\nbackground magnetic fields. In this situation Lorentz symmetry is broken and\nnew fundamental decay constants need to be introduced, associated with the\ndecay via the vector part of the electroweak current. We calculate the magnetic\nfield-dependence of both the usual and a new decay constant non-perturbatively\non the lattice. We employ both Wilson and staggered quarks and extrapolate the\nresults to the continuum limit. With this non-perturbative input we calculate\nthe tree-level electroweak amplitude for the full decay rate in strong magnetic\nfields. We find that the muonic decay of the charged pion is enhanced\ndrastically by the magnetic field. We comment on possible astrophysical\nimplications.",
        "positive": "Ginsparg-Wilson fermions: practical aspects and applications: I review recent progress in the implementation of lattice fermions satisfying\nthe Ginsparg-Wilson relation and some physical applications."
    },
    {
        "anchor": "Generalized Parton Distributions from Lattice QCD with Asymmetric\n  Momentum Transfer: Axial-vector case: Recently, we made significant advancements in improving the computational\nefficiency of lattice QCD calculations for Generalized Parton Distributions\n(GPDs). This progress was achieved by adopting calculations of matrix elements\nin asymmetric frames, deviating from the computationally-expensive symmetric\nframe typically used, and allowing freedom in the choice for the distribution\nof the momentum transfer between the initial and final states. A crucial aspect\nof this approach involves the adoption of a Lorentz covariant parameterization\nfor the matrix elements, introducing Lorentz-invariant amplitudes. This\napproach also allows us to propose an alternative definition of quasi-GPDs,\nensuring frame independence and potentially reduce power corrections in\nmatching to light-cone GPDs. In our previous work, we presented lattice QCD\nresults for twist-2 unpolarized GPDs ($H$ and $E$) of quarks obtained from\ncalculations performed in asymmetric frames at zero skewness. Building upon\nthis work, we now introduce a novel Lorentz covariant parameterization for the\naxial-vector matrix elements. We employ this parameterization to compute the\naxial-vector GPD $\\widetilde{H}$ at zero skewness, using an $N_f=2+1+1$\nensemble of twisted mass fermions with clover improvement. The light-quark\nmasses employed in our calculations correspond to a pion mass of approximately\n260 MeV.",
        "positive": "Overlap of the Wilson loop with the broken-string state: Numerical experiments on most gauge theories coupled with matter failed to\nobserve string-breaking effects while measuring Wilson loops only. We show\nthat, under rather mild assumptions, the overlap of the Wilson loop operator\nwith the broken-string state obeys a natural upper bound implying that the\nsignal of string-breaking is in general too weak to be detected by the\nconventional updating algorithms.\n  In order to reduce the variance of the Wilson loops in 3-D Z_2 gauge Higgs\nmodel we use a new algorithm based on the L\\\"uscher-Weisz method combined with\na non-local cluster algorithm which allows to follow the decay of rectangular\nWilson loops up to values of the order of 10^{-24}. In this way a sharp signal\nof string breaking is found."
    },
    {
        "anchor": "Determination of $B_K$ using improved staggered fermions (IV) One-loop\n  matching: We discuss the impact of using one-loop matching on the calculation of $B_K$\nusing HYP-smeared improved staggered fermions. We give estimates of size of the\ntruncation errors from the missing two-loop corrections.",
        "positive": "Lattice calculation of the Isgur-Wise functions tau_{1/2} and tau_{3/2}\n  with dynamical quarks: We perform a dynamical lattice computation of the Isgur-Wise functions\ntau_{1/2} and tau_{3/2} at zero recoil. We consider three different light quark\nmasses corresponding to 300 MeV < m_{PS} < 450 MeV, which allow us to\nextrapolate our results to the physical u/d quark mass. We find tau_{1/2}(1) =\n0.296(26) and tau_{3/2}(1) = 0.526(23). Uraltsev's sum rule is saturated up to\n80% by the ground state. We discuss implications regarding semileptonic decays\nB --> X_c l nu and the associated \"1/2 versus 3/2\" puzzle."
    },
    {
        "anchor": "Magnetic Monopoles, Center Vortices and Topology of Gauge Fields: The topological properties of magnetic monopoles and center vortices arising,\nrespectively, in Abelian and center gauges are studied in continuum Yang-Mills\nTheory. For this purpose the continuum analog of the maximum center gauge is\nconstructed.",
        "positive": "Dynamical Linked Cluster Expansions: A Novel Expansion Scheme for\n  Point-Link-Point-Interactions: Dynamical linked cluster expansions are linked cluster expansions with\nhopping parameter terms endowed with their own dynamics. This amounts to a\ngeneralization from 2-point to point-link-point interactions. We develop an\nassociated graph theory with a generalized notion of connectivity and describe\nan algorithmic generation of the new multiple-line graphs. We indicate physical\napplications to spin glasses, partially annealed neural networks and SU(N)\ngauge Higgs systems. In particular the new expansion technique provides the\npossibility of avoiding the replica-trick in spin glasses. We consider\nvariational estimates for the SU(2) Higgs model of the electroweak phase\ntransition. The results for the transition line, obtained by dynamical linked\ncluster expansions, agree quite well with corresponding high precision Monte\nCarlo results."
    },
    {
        "anchor": "$B_K$ Using Staggered Fermions: An Update: Improved results for $B_K$ are discussed. Scaling corrections are argued to\nbe of $O(a^2)$, leading to a reduction in the systematic error. For a kaon\ncomposed of degenerate quarks, the quenched result is ${\\widehat{B}_K} = 0.825\n\\pm 0.027 \\pm 0.023$.",
        "positive": "Insight into the Role of Instantons and their Zero Modes from Lattice\n  QCD: Evidence from lattice QCD calculations is presented showing that instantons\nand their associated zero modes play a major role in the physics of light\nhadrons and the propagation of light quarks in the QCD vacuum."
    },
    {
        "anchor": "Breakdown of staggered fermions at nonzero chemical potential: The staggered fermion determinant is complex when the quark chemical\npotential mu is nonzero. Its fourth root, used in simulations with dynamical\nfermions, will have phase ambiguities that become acute when Re mu is\nsufficiently large. We show how to resolve these ambiguities, but our\nprescription only works very close to the continuum limit. We argue that this\nregime is far from current capabilities. Other procedures require being even\ncloser to the continuum limit, or fail altogether, because of unphysical\ndiscontinuities in the measure. At zero temperature the breakdown is expected\nwhen Re mu is greater than approximately half the pion mass. Estimates of the\nlocation of the breakdown at nonzero temperature are less certain.",
        "positive": "The effect of sea quarks on the mass of the charm quark from Lattice QCD: We compute the mass of the charm quark using both quenched and dynamical\nlattice QCD calculations. We examine the effects of mass dependent lattice\nartifacts by comparing two different formalisms for the heavy quarks. We take\nthe continuum limit of the charm mass in quenched QCD by extrapolating from\nthree different lattice spacings. At a fixed lattice spacing, the mass of the\ncharm quark is compared between quenched QCD and dynamical QCD with a sea quark\nmass around strange. In the continuum limit of quenched QCD, we find\nm_c(m_c)=1.29(7)(13) GeV. No evidence was seen for unquenching."
    },
    {
        "anchor": "Reducing the number of counterterms with new minimally doubled actions: We study a class of nearest-neighbor minimally doubled actions which depend\non 2 continuous parameters. We calculate the contributions of the 3 possible\ncounterterms in perturbation theory, and we find that for each counterterm\nthere are curves in the parameter space on which its coefficient vanishes. One\ncan thus construct renormalized actions that contain only 2 counterterms\ninstead of the 3 of the standard Karsten-Wilczek or Borici-Creutz actions.\n  Our investigations suggest the usefulness of analogous nonperturbative\nsearches for values of the parameters for which the number of counterterms can\nbe reduced. They can also be an inspiration to undertake a search for\nultralocal minimally doubled actions with even better counterterm-reducing\nproperties, including the optimal case in which all counterterms can be\nremoved. Simulations of the latter actions will be much cheaper than the cases\nin which one needs to add counterterms to the bare actions, like the already\nconveniently inexpensive standard Karsten-Wilczek fermions.\n  Finally, we also introduce minimally doubled fermions with\nnext-to-nearest-neighbor interactions, which depend on 4 continuous parameters,\nas a further possibility in the search for renormalized actions with no\ncounterterms.",
        "positive": "Monte-Carlo study of the $\u0394\u03c1$ parameter: We present results concerning a lattice study of the electroweak\n$\\rho$-parameter. We have used an SU(2)$\\times$U(1) symmetric chiral Yukawa\nmodel built with Zaragoza fermions. The decoupling of the species doublers in\nthis model is verified numerically. We find that the numerical data for\n$\\Delta\\rho$ are well described by one-loop perturbation theory with the same\nfinite volume and with the same finite cut-off. However, a finite cut-off can\ncause substantial deviations of $\\Delta\\rho$ from the standard value, even in\ninfinite volume."
    },
    {
        "anchor": "Multi-Grid Monte Carlo III. Two-Dimensional O(4)-Symmetric Nonlinear\n  $\u03c3$-Model: We study the dynamic critical behavior of the multi-grid Monte Carlo (MGMC)\nalgorithm with piecewise-constant interpolation applied to the two-dimensional\nO(4)-symmetric nonlinear $\\sigma$-model [= SU(2) principal chiral model], on\nlattices up to $256 \\times 256$. We find a dynamic critical exponent\n$z_{int,{\\cal M}^2} = 0.60 \\pm 0.07$ for the W-cycle and $z_{int,{\\cal M}^2} =\n1.13 \\pm 0.11$ for the V-cycle, compared to $z_{int,{\\cal M}^2} = 2.0 \\pm 0.15$\nfor the single-site heat-bath algorithm (subjective 68% confidence intervals).\nThus, for this asymptotically free model, critical slowing-down is greatly\nreduced compared to local algorithms, but not completely eliminated. For a $256\n\\times 256$ lattice, W-cycle MGMC is about 35 times as efficient as a\nsingle-site heat-bath algorithm.",
        "positive": "Linear broadening of the confining string in Yang-Mills theory at low\n  temperature: The logarithmic broadening predicted by the systematic low-energy effective\nfield theory for the confining string has recently been verified in numerical\nsimulations of (2+1)-d SU(2) lattice Yang-Mills theory at zero temperature. The\nsame effective theory predicts linear broadening of the string at low non-zero\ntemperature. In this paper, we verify this prediction by comparison with very\nprecise Monte Carlo data. The comparison involves no additional adjustable\nparameters, because the low-energy constants of the effective theory have\nalready been fixed at zero temperature. It yields very good agreement between\nthe underlying Yang-Mills theory and the effective string theory."
    },
    {
        "anchor": "$|V_{us}|$ from kaon semileptonic form factor in $N_f = 2+1$ QCD at the\n  physical point on (10 fm)$^4$: We present a preliminary result of the kaon semileptonic form factor\ncalculated at the smallest lattice spacing in the PACS10 configurations, whose\nphysical volumes are more than (10 fm)$^4$ at the physical point. The\nconfigurations were generated using the Iwasaki gauge action and $N_f=2+1$\nstout-smeared nonperturbatively $O(a)$ improved Wilson quark action at the\nthree lattice spacings, 0.085, 0.063, and 0.041 fm. The value of $|V_{us}|$ in\nthe continuum limit is estimated from our results including the preliminary\none. We compare our result of $|V_{us}|$ with the previous results and those\nthrough the kaon leptonic decay.",
        "positive": "A numerical study of confinement in compact QED: Compact U(1) lattice gauge theory in four dimensions is studied by means of\nan efficient algorithm which exploits the duality transformation properties of\nthe model. We focus our attention onto the confining regime, considering the\ninterquark potential and force, and the electric field induced by two\ninfinitely heavy sources. We consider both the zero and finite temperature\nsetting, and compare the theoretical predictions derived from the effective\nstring model and the dual superconductor scenario to the numerical results."
    },
    {
        "anchor": "Mass Spectrum and Bounds on the Couplings in Yukawa Models With\n  Mirror-Fermions: The $\\rm SU(2)_L\\otimes SU(2)_R$ symmetric Yukawa model with mirror-fermions\nin the limit where the mirror-fermion is decoupled is studied both analytically\nand numerically. The bare scalar self-coupling $\\lambda$ is fixed at zero and\ninfinity. The phase structure is explored and the relevant phase transition is\nfound to be consistent with a second order one. The fermionic mass spectrum\nclose to that transition is discussed and a first non-perturbative estimate of\nthe influence of fermions on the upper and lower bounds on the renormalized\nscalar self-coupling is given. Numerical results are confronted with\nperturbative predictions.",
        "positive": "A Numerical Test of KPZ Scaling: Potts Models Coupled to Two-Dimensional\n  Quantum Gravity: We perform Monte Carlo simulations using the Wolff cluster algorithm of the\nq=2 (Ising), 3, 4 and q=10 Potts models on dynamical phi-cubed graphs of\nspherical topology with up to 5000 nodes. We find that the measured critical\nexponents are in reasonable agreement with those from the exact solution of the\nIsing model and with those calculated from KPZ scaling for q=3,4 where no exact\nsolution is available. Using Binder's cumulant we find that the q=10 Potts\nmodel displays a first order phase transition on a dynamical graph, as it does\non a fixed lattice. We also examine the internal geometry of the graphs\ngenerated in the simulation, finding a linear relationship between ring length\nprobabilities and the central charge of the Potts model"
    },
    {
        "anchor": "Penta-quark baryon in anisotropic lattice QCD: The penta-quark(5Q) baryon is studied in anisotropic quenched lattice QCD\nwith renormalized anisotropy a_s/a_t=4 for a high-precision mass measurement.\nThe standard Wilson action at beta=5.75 and the O(a) improved Wilson quark\naction with kappa=0.1210(0.0010)0.1240 are employed on a 12^3 \\times 96\nlattice. Contribution of excited states is suppressed by using a smeared\nsource. We investigate both the positive- and negative-parity 5Q baryons with\nI=0 and spin J=1/2 using a non-NK-type interpolating field. After chiral\nextrapolation, the lowest positive-parity state is found to have a mass,\nm_{Theta}=2.25 GeV, which is much heavier than the experimentally observed\nTheta^+(1540). The lowest negative-parity 5Q appears at m_{Theta}=1.75 GeV,\nwhich is near the s-wave NK threshold. To distinguish spatially-localized 5Q\nresonances from NK scattering states, we propose a new general method imposing\na ``Hybrid Boundary Condition (HBC)'', where the NK threshold is artificially\nraised without affecting compact five-quark states. The study using the HBC\nmethod shows that the negative-parity state observed on the lattice is not a\ncompact 5Q but an s-wave NK-scattering state.",
        "positive": "Kaon physics from lattice QCD: I review lattice calculations and results for hadronic parameters relevant\nfor kaon physics, in particular the vector form factor f+(0) of semileptonic\nkaon decays, the ratio fK/fpi of leptonic decay constants and the kaon bag\nparameter BK. For each lattice calculation a colour code rating is assigned, by\nfollowing a procedure which is being proposed by the Flavianet Lattice\nAveraging Group (FLAG), and the following final averages are obtained:\nf+(0)=0.962(3)(4), fK/fpi = 1.196(1)(10) and \\hat BK = 0.731(7)(35). In the\nlast part of the talk, the present status of lattice studies of non-leptonic\nK--> pi pi decays is also briefly summarized."
    },
    {
        "anchor": "Characters of Lattice Fermions Based on the Hyperdiamond Lattice: We study minimal-doubling fermion actions on hyperdiamond and deformed\nhyperdiamond lattices, with emphasis on the real-space construction of them and\nLorentz covariance of excitations from fermion poles. We propose the improved\nspatial construction of Creutz fermion action on a deformed hyperdiamond\nlattice, and discuss conditions for a hyperdiamond-lattice action to produce\nLorentz-covariant excitations from poles of fermion propagators. It is pointed\nout that the non-nearest-site hoppings are essential for the correct\nexcitations. We propose a class of minimal-doubling actions defined on a\ndeformed hypercubic lattice as a generalization of Creutz-type actions. In\naddition we introduce a two-parameter class of Wilczek-type minimal-doubling\nactions.",
        "positive": "Determination of the $\u0394(1232)$ axial and pseudoscalar form factors\n  from lattice QCD: We present a lattice QCD calculation of the $\\Delta(1232)$ matrix elements of\nthe axial-vector and pseudoscalar currents. The decomposition of these matrix\nelements into the appropriate Lorentz invariant form factors is carried out and\nthe techniques to calculate the form factors are developed and tested using\nquenched configurations. Results are obtained for 2+1 domain wall fermions and\nwithin a hybrid scheme with domain wall valence and staggered sea quarks. Two\nGoldberger-Treiman type relations connecting the axial to the pseudoscalar\neffective couplings are derived. These and further relations based on the\npion-pole dominance hypothesis are examined using the lattice QCD results,\nfinding support for their validity. Utilizing lattice QCD results on the axial\ncharges of the nucleon and the $\\Delta$, as well as the nucleon-to-$\\Delta$\ntransition coupling constant, we perform a combined chiral fit to all three\nquantities and study their pion mass dependence as the chiral limit is\napproached."
    },
    {
        "anchor": "Performance optimizations for porting the openQ$^\\star$D package to GPUs: OpenQ$^\\star$D code has been used by the RC$^\\star$ collaboration for the\ngeneration of fully dynamical QCD+QED gauge configurations with C$^\\star$\nboundary conditions. In this talk, optimization of solvers provided with the\nopenQ$^\\star$D package relevant for porting the code on GPU-accelerated\nsupercomputing platforms is discussed. We present the analysis of the current\nimplementations of the GCR solver preconditioned with Schwarz alternating\nprocedure for ill-conditioned Dirac-operators. With the goal of enabling\nsupport for GPUs from various vendors, a novel method of adaptive\nCPU/GPU-hybrid implementation is proposed.",
        "positive": "Quenched Scaling of Wilson twisted mass fermions: We investigate the scaling behaviour of quenched Wilson twisted mass fermions\nat maximal twist applying two definitions of the critical mass. The first\ndefinition uses the vanishing of the pseudoscalar meson mass m_PS while the\nsecond employs the vanishing of the PCAC quark mass m_PCAC. We confirm in both\ncases the expected O(a) improvement. In addition, we show that the PCAC quark\nmass definition leads to substantially reduced O(a^2) cut-off effects even when\nthe pseudoscalar meson mass m_PS is as small as 270 MeV. At a fixed value of\nm_PS we perform continuum limits for the vector meson mass m_V and for the\npseudoscalar decay constant f_PS and discuss the renormalisation constant Z_V\nof the vector current."
    },
    {
        "anchor": "Hubbard Model with Luscher fermions: First applications of the new algorithm simulating dynamical fermions are\nreported. The method reproduces previous results obtained with different\ntechniques.",
        "positive": "Multicanonical Cluster Algorithm: In this talk I present a multicanonical hybrid-like two-step algorithm, which\nconsists of a microcanonical spin system update with demons, and a\nmulticanonical demon refresh. The demons act as a buffer between the\nmulticanonical heat bath and the spin system, allowing for a large variety of\nupdate schemes. In this work the cluster algorithm is demonstrated with the\n2-dimensional 7-state Potts model, using volumes up to $128^2$."
    },
    {
        "anchor": "Density of states approach for lattice gauge theory with a $\u03b8$-term: We discuss a new strategy for treating the complex action problem of lattice\nfield theories with a $\\theta$-term based on density of states (DoS) methods.\nThe key ingredient is to use open boundary conditions where the topological\ncharge is not quantized to integers and the density of states is sufficiently\nwell behaved such that it can be computed precisely with recently developed DoS\ntechniques. After a general discussion of the approach and the role of the\nboundary conditions, we analyze the method for 2-d U(1) lattice gauge theory\nwith a $\\theta$-term, a model that can be solved in closed form. We show that\nin the continuum limit periodic and open boundary conditions describe the same\nphysics and derive the DoS, demonstrating that only for open boundary\nconditions the density is sufficiently well behaved for a numerical evaluation.\nWe conclude our proof of principle analysis with a small test simulation where\nwe numerically compute the density and compare it with the analytical result.",
        "positive": "Vortices and monopole distributions in $Z(2) \\times SO(3)$ lattice gauge\n  theory: We examine the occurance of Z(2) and SO(3) vorticies and monopole\ndistributions in the neighborhood of Wilson loops. We use the Tomboulis\nformulation, equivalent to the Wilson action, in which the links are invariant\nunder Z(2) transformations and new plaquette variables carry the Z(2) degrees\nof freedom. This gives new gauge invariant observables to help gain insight\ninto the area law and structure of the flux tube."
    },
    {
        "anchor": "Finite-Size Effects of the HVP Contribution to the Muon $g-2$ with\n  C$^{\\star}$ Boundary Conditions: The muon $g-2$ is a compelling quantity due to the current standing tensions\namong the experimental average, data-driven theoretical results, and lattice\nresults. Matching the final target accuracy of the experiments at Fermilab and\nJ-PARC will constitute a major challenge for the lattice community in the\ncoming years. For this reason, it is worthwhile to consider different options\nto keep the systematic errors under control. In this proceedings, we discuss\nfinite-volume effects of the leading Hadron Vacuum Polarization (HVP)\ncontribution to the muon $g-2$ in the presence of C$^{\\star}$ boundary\nconditions. When considering isospin-breaking corrections to the HVP,\nC$^{\\star}$ boundary conditions provide a possible consistent formulation of\n$\\mathrm{QCD+QED}$ in finite volume. Even though these boundary conditions can\nbe avoided in the calculation of the leading HVP contribution, we find the\ninteresting result that they remove the leading exponential finite-volume\ncorrection. In practice, compared to the periodic case, C$^{\\star}$ boundary\nconditions cut the finite-size effects in half on a lattice of physical size\n$M_{\\pi}L=4$ and by a factor of almost ten for $M_{\\pi}L=8$. We discuss the\norigin of this reduction and implications for computational efficiency.",
        "positive": "Towards a precise determination of the topological susceptibility in the\n  SU(3) Yang-Mills theory: An ongoing effort to compute the topological susceptibility for the SU(3)\nYang-Mills theory in the continuum limit with a precison of about 2% is\nreported. The susceptibility is computed by using the definition of the charge\nsuggested by Neuberger fermions for two values of the negative mass parameter\ns. Finite volume and discretization effects are estimated to meet this level of\nprecision. The large statistics required has been obtained by using PCs of the\nINFN-GRID. Simulations with larger lattice volumes are necessary in order to\nbetter understanding the continuum limit at small lattice spacing values."
    },
    {
        "anchor": "3-D lattice simulation of the electroweak phase transition at small\n  Higgs mass: We study the electroweak phase transition by lattice simulations of an\neffective 3-dimensional theory, for a Higgs mass of about $35 GeV$. In the\nbroken symmetry phase our results on masses and the Higgs condensate are\nconsistent with 2-loop perturbative results. However, we find a\nnon-perturbative lowering of the transition temperature, similar to the one\npreviously found at $m_H = 80 GeV$. For the symmetric phase, bound state masses\nand the static force are determined and compared with results for pure $SU(2)$\ntheory.",
        "positive": "$K\\to\u03c0\u03c0$ from electroweak penguins in $N_f=2$ domain-wall QCD: We present the calculation of $K\\to\\pi\\pi$ matrix elements of electroweak\npenguin operators {\\it i.e.} $Q_7$ and $Q_8$. In the numerical simulation, we\nuse the gauge configurations generated by the combination of $N_f=2$\ndomain-wall fermions and DBW2 gauge action. From $K\\to\\pi$ and $K\\to 0$ matrix\nelements on the lattice, we construct $K\\to\\pi\\pi$ matrix elements at\nnext-to-leading order in the chiral expansion by using recent analytic results.\nRenormalization factor of these matrix elements are obtained by the\nnon-perturbative renormalization technique in RI/MOM scheme. Brief discussion\nbased on our results are made as well as a comparison with previous works."
    },
    {
        "anchor": "Non-perturbative quark mass renormalization in quenched lattice QCD: The renormalization factor relating the bare to the renormalization group\ninvariant quark masses is accurately calculated in quenched lattice QCD using a\nrecursive finite-size technique. The result is presented in the form of a\nproduct of a universal factor times another factor, which depends on the\ndetails of the lattice theory but is easy to compute, since it does not involve\nany large scale differences. As a byproduct the Lambda-parameter of the theory\nis obtained with a total error of 8%.",
        "positive": "Monopole Loop Distribution and Confinement in SU(2) Lattice Gauge Theory: The abelian-projected monopole loop distribution is extracted from maximal\nabelian gauge simulations. The number of loops of a given length falls as a\npower of the length nearly independent of lattice size. This power increases\nwith $\\beta=4/g^2$, reaching five around $\\beta=2.85$, beyond which loops any\nfinite fraction of the lattice size vanish in the infinite lattice limit,\nsuggesting the continuum theory lacks confinement."
    },
    {
        "anchor": "The radial distributions of a heavy-light meson on a lattice: In an earlier work, the charge (vector) and matter (scalar) radial\ndistributions of heavy-light mesons were measured in the quenched approximation\non a 16^3 times 24 lattice with a quark-gluon coupling of 5.7, a lattice\nspacing of 0.17 fm, and a hopping parameter corresponding to a light quark mass\nabout that of the strange quark.\n  Several improvements are now made: 1) The configurations are generated using\ndynamical fermions with a quark-gluon coupling of 5.2 (a lattice spacing of\n0.14 fm); 2) Many more gauge configurations are included (78 compared with the\nearlier 20); 3) The distributions at many off-axis, in addition to on-axis,\npoints are measured; 4) The data-analysis is much more complete. In particular,\ndistributions involving excited states are extracted.\n  The exponential decay of the charge and matter distributions can be described\nby mesons of mass 0.9+-0.1 and 1.5+-0.1 GeV respectively - values that are\nconsistent with those of vector and scalar qqbar-states calculated directly\nwith the same lattice parameters.",
        "positive": "Gradient flow and IR fixed point in SU(2) with Nf=8 flavors: We study the running of the coupling in SU(2) gauge theory with 8 massless\nfundamental representation fermion flavours, using the gradient flow method\nwith the Schr\\\"odinger functional boundary conditions. Gradient flow allows us\nto measure robust continuum limit for the step scaling function. The results\nshow a clear indication of infrared fixed point consistent with perturbation\ntheory."
    },
    {
        "anchor": "The L\u00fcscher scattering formalism on the $t$-channel cut: The L\\\"uscher scattering formalism, the standard approach for relating the\ndiscrete finite-volume energy spectrum to two-to-two scattering amplitudes,\nfails when analytically continued so far below the infinite-volume two-particle\nthreshold that one encounters the $t$-channel cut. This is relevant, especially\nin baryon-baryon scattering applications, as finite-volume energies can be\nobserved in this below-threshold regime, and it is not clear how to make use of\nthem. In this talk, we present a generalization of the scattering formalism\nthat resolves this issue, allowing one to also constrain scattering amplitudes\non the $t$-channel cut.",
        "positive": "A fully non-perturbative charm-quark tuning using machine learning: We present a relativistic heavy-quark action tuning for the charm sector on\nensembles generated by the CLS consortium. We tune a particular 5-parameter\naction in an entirely non-perturbative and -- up to the chosen experimental\ninput -- model-independent way using machine learning and the continuum\nexperimental charmonium ground-state masses with various quantum numbers. In\nthe end we are reasonably successful; obtaining a set of simulation parameters\nthat we then verify produces the expected spectrum. In the future, we will use\nthis action for finite-volume calculations of hadron-hadron scattering."
    },
    {
        "anchor": "Infinite lattice models by expansion with a non-Gaussian initial\n  approximation: Recently, a convergent series employing a non-Gaussian initial approximation\nwas constructed and shown to be an effective computational tool for the finite\nsize lattice models with a polynomial interaction. Here we numerically examine\nthe applicability of the convergent series method to models defined on infinite\nlattices. The comparison of the convergent series computations and the infinite\nlattice extrapolations of the Monte Carlo simulations reveals an agreement\nbetween two approaches.",
        "positive": "Chiral symmetry restoration of QCD and the Gross-Neveu model: Two flavour massless QCD has a second order chiral transition which has been\nargued to belong to the universality class of the $3d$ O(4) spin model. The\narguments have been questioned recently, and the transition was claimed to be\nmean field behaved. We discuss this issue at the example of the $3d$\nGross-Neveu model. A solution is obtained by applying various well established\nanalytical methods."
    },
    {
        "anchor": "Electromagnetic effects on the light pseudoscalar mesons and\n  determination of $m_u/m_d$: The MILC Collaboration has completed production running of electromagnetic\neffects on light mesons using asqtad improved staggered quarks. In these\ncalculations, we use quenched photons in the noncompact formalism. We study\nfour lattice spacings from $\\approx\\!0.12\\:$fm to $\\approx\\!0.045\\:$fm. To\nstudy finite-volume effects, we used six spatial lattice sizes $L/a=12$, 16,\n20, 28, 40, and 48, at $a\\!\\approx\\!0.12\\:$fm. We update our preliminary values\nfor the correction to Dashen's theorem ($\\epsilon$) and the quark-mass ratio\n$m_u/m_d$.",
        "positive": "Suppression of excited-state effects in lattice determination of nucleon\n  electromagnetic form factors: We study the ability of a variety of fitting techniques to extract the ground\nstate matrix elements of the vector current from ratios of nucleon three- and\ntwo-point functions that contain contaminations from excited states. Extending\nour high-statistics study of nucleon form factors, we are able to demonstrate\nthat the treatment of excited-state contributions in conjunction with\napproaching the physical pion mass has a significant impact on the\n$Q^2$-dependence of the form factors."
    },
    {
        "anchor": "Meson correlation functions at high temperature QCD: $SU(2)_{CS}$\n  symmetry vs. free quarks: We report on the progress of understanding spatial correlation functions in\nhigh temperature QCD. We study isovector meson operators in $N_f=2$ QCD using\ndomain-wall fermions on lattices of $N_s=32$ and different quark masses. It has\npreviously been found that at $\\sim 2T_c$ these observables are not only\nchirally symmetric but in addition approximately $SU(2)_{CS}$ and $SU(4)$\nsymmetric. In this study we increase the temperature up to $5T_c$ and can\nidentify convergence towards an asymptotically free scenario at very high\ntemperatures.",
        "positive": "Moments and power corrections of longitudinal and transverse proton\n  structure functions from lattice QCD: We present a simultaneous extraction of the moments of $F_2$ and $F_L$\nstructure functions of the proton for a range of photon virtuality, $Q^2$. This\nis achieved by computing the forward Compton amplitude on the lattice utilizing\nthe second-order Feynman-Hellmann theorem. Our calculations are performed on\nconfigurations with two different lattice spacings and volumes, all at the\n$SU(3)$ symmetric point. We find the moments of $F_{2}$ and $F_{L}$ in good\nagreement with experiment. Power corrections turn out to be significant. This\nis the first time the $Q^2$ dependence of the lowest moment of $F_2$ has been\nquantified."
    },
    {
        "anchor": "Charm Quarks and the QCD Equation of State: We present a study of the effect of charm quarks on the QCD equation of state\nusing partially-quenched p4 charm quarks on a dynamically generated 2+1 flavor\nbackground, at zero chemical potential. We show preliminary results for the\ncharm quark contribution to the energy density and pressure in the high\ntemperature region ($T_c < T < 4 T_c$) and compare it to the free-field\ncalculation. The charm quark mass is determined by measuring the charmonium\nspectrum.",
        "positive": "Fine-Tuning of the Yukawa and Quartic Couplings in Supersymmetric QCD: In this work, we investigate the fine tuning of parameters in $\\mathcal{N} =\n1$ Supersymmetric QCD, discretized on a Euclidean lattice. Specifically, we\nstudy the renormalization of the Yukawa (gluino-quark-squark interactions) and\nthe quartic (four-squark interactions) couplings. At the quantum level, these\ninteractions suffer from mixing with other operators which have the same\ntransformation properties. We exploit the symmetries of the action, such as\ncharge conjugation and parity, in order to reduce the allowed mixing patterns.\nTo deduce the renormalizations and the mixing coefficients we compute,\nperturbatively to one-loop and to the lowest order in the lattice spacing, the\nrelevant three-point and four-point Green's functions using both dimensional\nand lattice regularizations. Our lattice formulation involves the Wilson\ndiscretization for the gluino and quark fields; for gluons we employ the Wilson\ngauge action; for scalar fields (squarks) we use na\\\"ive discretization. We\nobtain analytic expressions for the renormalization and mixing coefficients of\nthe Yukawa couplings; they are functions of the number of colors $N_c$, the\ngauge parameter $\\alpha$, and the gauge coupling $g$. Furthermore, preliminary\nresults on the quartic couplings are also presented."
    },
    {
        "anchor": "Interaction potentials for two-particle states with non-zero total\n  momenta in lattice QCD: In this study, we extend the HAL QCD method to a case where a total momentum\nof a two-particle system is non-zero and apply it to the $I=2$ S-wave $\\pi\\pi$\nscattering in order to confirm its validity. We derive a fundamental relation\nof an energy-independent non-local potential defined in the center of mass\nframe with NBS wave functions in a laboratory frame. Based on the relation, we\npropose the time-dependent method to extract potentials, often used in practice\nfor the HALQCD method in the center of mass frame. For numerical simulations in\nthe $I=2$ $\\pi\\pi$ system, we employ (2+1)-flavor gauge configurations on a\n$32^3 \\times 64$ lattice at the lattice spacing $a \\approx 0.0907$ fm and\n$m_{\\pi} \\approx 700$ MeV. Both effective leading order (LO) potentials and\ncorresponding phase shifts obtained in laboratory frames agree with those\nobtained in the center-of-mass frame by the conventional HAL QCD method within\nsomewhat larger statistical errors. In addition, we observe a consistency in\nscattering phase shifts between ours and results by the finite-volume method as\nwell. The HAL QCD method with non-zero total momenta, established in this\nstudy, brings more flexibility to the HAL QCD method, which enables us to\nhandle systems having the same quantum numbers with a vacuum or to access\nenergy regions prohibited in the center of mass frame.",
        "positive": "Chromoelectric and chromomagnetic fields for the static\n  gluon-quark-antiquark system: The chromoelectric and chromomagnetic fields, created by a static\ngluon-quark-antiquark system, are computed in the quenched approximation of\nlattice QCD, in a $24^3\\times 48$ lattice at $\\beta=6.2$. We study two\ngeometries, one with a U shape and another with an L shape. The degenerate case\nof the two gluon glueball is also studied. This is relevant to understand the\nmicroscopic structure of hadrons, in particular of hybrids. This also\ncontributes to understand confinement with flux tubes of the chromoelectric\nfield, and to discriminate between the models of fundamental or adjoint tubes."
    },
    {
        "anchor": "Monte Carlo determination of the critical coupling in $\u03c6^4_2$ theory: We use lattice formulation of $\\phi^4$ theory in order to investigate\nnon--perturbative features of its continuum limit in two dimensions. In\nparticular, by means of Monte Carlo calculations, we obtain the critical\ncoupling constant $g/\\mu^2$ in the continuum, where $g$ is the {\\em\nunrenormalised} coupling. Our final result is $g/\\mu^2=11.15(6)(3)$.",
        "positive": "Critical behavior of the hopping expansion from the Functional\n  Renormalization Group: A lattice version of the widely used Functional Renormalization Group (FRG)\nfor the Legendre effective action is solved - in principle exactly - in terms\nof graph rules for the linked cluster expansion. Conversely, the FRG induces\nnonlinear flow equations governing suitable resummations of the graph\nexpansion. The (finite) radius of convergence determining criticality can then\nbe efficiently computed as the unstable manifold of a Gaussian or non-Gaussian\nfixed point of the FRG flow. The correspondence is tested on the critical line\nof the L\\\"{u}scher-Weisz solution of the $\\phi^4_4$ theory and its $\\phi_3^4$\ncounterpart."
    },
    {
        "anchor": "Asymptotic freedom with discrete spin variables?: We study the critical behaviour of the 2d dodecahedron spin model and\ninvestigate the conjecture that the discrete model describes the same continuum\ntheory as the O(3) non-linear sigma model. In particular, we found that the\nanisotropy of the magnetization A(z) measured in a fixed physical volume\ndecreases with increasing correlation length, at least up to \\xi \\approx 1000.",
        "positive": "Calculating the Two-photon Contribution to $\u03c0^0 \\rightarrow e^+ e^-$\n  Decay Amplitude: We develop a new method that allows us to deal with two-photon intermediate\nstates in a lattice QCD calculation. We apply this method to perform a\nfirst-principles calculation of the $\\pi^0 \\rightarrow e^+ e^-$ decay\namplitude. Both the real and imaginary parts of amplitude are calculated. The\nimaginary part is compared with the prediction of optical theorem to\ndemonstrate the effectiveness of this method. Our result for the real part of\ndecay amplitude is $19.68(52)(1.10) \\ \\text{eV}$, where the first error is\nstatistical and the second is systematic."
    },
    {
        "anchor": "Nonperturbative beta function of eight-flavor SU(3) gauge theory: We present a new lattice study of the discrete beta function for SU(3) gauge\ntheory with Nf=8 massless flavors of fermions in the fundamental\nrepresentation. Using the gradient flow running coupling, and comparing two\ndifferent nHYP-smeared staggered lattice actions, we calculate the 8-flavor\nstep-scaling function at significantly stronger couplings than were previously\naccessible. Our continuum-extrapolated results for the discrete beta function\nshow no sign of an IR fixed point up to couplings of g^2~14. At the same time,\nwe find that the gradient flow coupling runs much more slowly than predicted by\ntwo-loop perturbation theory, reinforcing previous indications that the\n8-flavor system possesses nontrivial strongly coupled IR dynamics with\nrelevance to BSM phenomenology.",
        "positive": "Perturbative renormalization in parton distribution functions using\n  Overlap fermions and Symanzik improved gluons: We calculate the 1-loop renormalization of the fermion self-energy, all local\nfermion bilinears, as well as a set of extended bilinears which form a basis\ncorresponding to moments of the parton distribution functions.\n  We use the overlap action for fermions and Symanzik improved action for\ngluons.\n  Our results are presented as a function of the overlap parameter rho and the\nparameters entering the Symanzik action."
    },
    {
        "anchor": "A Lattice Formulation of Chiral Gauge Theories: We present a method for formulating gauge theories of chiral fermions in\nlattice field theory. The method makes use of a Wilson mass to remove doublers.\nGauge invariance is then restored by modifying the theory in two ways: the\nmagnitude of the fermion determinant is replaced with the square root of the\ndeterminant for a fermion with vector-like couplings to the gauge field; a\ndouble limit is taken, in which the lattice spacing associated with the fermion\nfield is sent to zero before the lattice spacing associated with the gauge\nfield. The method applies only to theories whose fermions are in an\nanomaly-free representation of the gauge group. We also present a related\ntechnique for computing matrix elements of operators involving fermion fields.\nAlthough the analyses of these methods are couched in weak-coupling\nperturbation theory, it is argued that the computational prescriptions are\ngauge invariant in the presence of a nonperturbative gauge-field configuration.",
        "positive": "Lifting flat directions in lattice supersymmetry: We present a procedure to improve the lattice definition of $\\mathcal N = 4$\nsupersymmetric Yang--Mills theory. The lattice construction necessarily\ninvolves U(1) flat directions, and we show how these can be lifted without\nviolating the exact lattice supersymmetry. The basic idea is to modify the\nequations of motion of an auxiliary field, which determine the moduli space of\nthe system. Applied to numerical calculations, the resulting improved lattice\naction leads to dramatically reduced violations of supersymmetric Ward\nidentities and much more rapid approach to the continuum limit."
    },
    {
        "anchor": "On the extraction of zero momentum form factors on the lattice: We propose a method to expand correlation functions with respect to the\nspatial components of external momenta. From the coefficients of the expansion\nit is possible to extract Lorentz-invariant form factors at zero spatial\nmomentum transfer avoiding model dependent extrapolations. These objects can be\nprofitably calculated on the lattice. We have explicitly checked the validity\nof the proposed procedure by considering two-point correlators with insertions\nof the axial current, the form factors of the semileptonic decay of\npseudoscalar mesons, and the hadronic vacuum polarization tensor entering, for\nexample, the lattice calculation of the anomalous magnetic moment of the muon.",
        "positive": "Light-cone QCD on the lattice: Ideas and recent results for light-front Hamiltonian quantisation of lattice\ngauge theories."
    },
    {
        "anchor": "Strong coupling and quark masses from lattice QCD: I review lattice QCD calculations of the strong coupling and quark masses.",
        "positive": "Chiral condensates and screening masses of neutral pseudoscalar mesons\n  in thermomagnetic QCD medium: We point out that chiral condensates at nonzero temperature and magnetic\nfields are in strict connection to the space-time integral of corresponding\ntwo-point neutral meson correlation functions in the pseudoscalar channel via\nthe Ward-Takahashi identity. Screening masses of neutral pseudoscalar mesons,\nwhich are defined as the exponential decay of the corresponding spatial\ncorrelation functions in the long distance, thus are intrinsically connected to\n(inverse) magnetic catalysis of chiral condensates. To study this we performed\nlattice simulations of $(2+1)$-flavor QCD on $32^3\\times N_t$ lattices with\npion mass $M_\\pi\\simeq 220$ MeV in a fixed scale approach having temperature\n$T\\in[17, 281]$ MeV and magnetic field strength $eB\\in[0, 2.5]$ GeV$^2$. We\nfind that screening lengths, i.e. inverses of screening masses of $\\pi^0$,\n$K^0$ and $\\eta^0_{s\\bar{s}}$, turn out to have the similar complex $eB$ and\n$T$ dependences of the corresponding chiral condensates. Although the\ntransition temperature is found to always decrease as $eB$ grows, we show that\nthe suppression due to magnetic fields becomes less significant for hadron\nscreening length and chiral condensates with heavier quarks involved, and\nceases to occur for $\\eta^0_{s\\bar{s}}$ and strange quark chiral condensate.\nThe complex $eB$ and $T$ dependences of both screening masses and chiral\ncondensates, reflecting the crossover nature of the QCD transition, are\nattributed to the competition between sea and valence quark effects. These\nfindings could be useful to guide low-energy models and effective theories of\nQCD."
    },
    {
        "anchor": "Canonical Transformations and Loop Formulation of SU(N) Lattice Gauge\n  Theories: We construct canonical transformations to reformulate SU(N) Kogut-Susskind\nlattice gauge theory in terms of a set of fundamental loop & string flux\noperators along with their canonically conjugate loop & string electric fields.\nWe show that as a consequence of SU(N) Gauss laws all SU(N) string degrees of\nfreedom become cyclic and decouple from the physical Hilbert space ${\\cal\nH}^p$. The canonical relations between the initial SU(N) link operators and the\nfinal SU(N) loop & string operators over the entire lattice are worked out in a\nself consistent manner. The Kogut-Susskind Hamiltonian rewritten in terms of\nthe fundamental physical loop operators has global SU(N) invariance. There are\nno gauge fields. We further show that the $(1/g^2)$ magnetic field terms on\nplaquettes create and annihilate the fundamental plaquette loop fluxes while\nthe $(g^2)$ electric field terms describe all their interactions. In the weak\ncoupling ($g^2 \\rightarrow 0$) continuum limit the SU(N) loop dynamics is\ndescribed by SU(N) spin Hamiltonian with nearest neighbour interactions. In the\nsimplest SU(2) case, where the canonical transformations map the SU(2) loop\nHilbert space into the Hilbert spaces of hydrogen atoms, we analyze the special\nrole of the hydrogen atom dynamical symmetry group $SO(4,2)$ in the loop\ndynamics and the spectrum. A simple tensor network ansatz in the SU(2) gauge\ninvariant hydrogen atom loop basis is discussed.",
        "positive": "Visualization of semileptonic form factors from lattice QCD: Comparisons of lattice-QCD calculations of semileptonic form factors with\nexperimental measurements often display two sets of points, one each for\nlattice QCD and experiment. Here we propose to display the output of a\nlattice-QCD analysis as a curve and error band. This is justified, because\nlattice-QCD results rely in part on fitting, both for the chiral extrapolation\nand to extend lattice-QCD data over the full physically allowed kinematic\ndomain. To display an error band, correlations in the fit parameters must be\ntaken into account. For the statistical error, the correlation comes from the\nfit. To illustrate how to address correlations in the systematic errors, we use\nthe Becirevic-Kaidalov parametrization of the D -> pi l nu and D -> K l nu form\nfactors, and a analyticity-based fit for the B -> pi l nu form factor f_+."
    },
    {
        "anchor": "Update on $B_K$ and $\\varepsilon_K$ with staggered quarks: We update our results for $B_K$ obtained using HYP-smeared staggered valence\nquarks on the MILC asqtad lattices. In the last year, we have added 5 new\nmeasurments on the fine ($a\\approx 0.09\\;$fm) ensembles, and 2 new measurements\non the superfine ($a\\approx 0.06\\;$fm) ensembles. These allow a simultaneous\nextrapolation in $a^2$ and sea quark masses, reducing the corresponding\nsystematic error significantly. Our updated result is $\\hat{B}_K = 0.738 \\pm\n0.005 (\\text{stat}) \\pm 0.034 (\\text{sys})$.",
        "positive": "Bayesian inference of real-time dynamics from lattice QCD: The computation of dynamical properties of nuclear matter, ranging from\nparton distribution functions of nucleons and nuclei to transport properties in\nthe quark-gluon plasma, constitutes a central goal of modern theoretical\nphysics. This real-time physics often defies a perturbative treatment and the\nmost successful strategy so far is to deploy lattice QCD simulations. These\nnumerical computations are based on Monte-Carlo sampling and formulated in an\nartificial Euclidean time. Real-time physics is most conveniently formulated in\nterms of spectral functions, which are hidden in lattice QCD behind an\nill-posed inverse problem. I will discuss the current methods state-of-the art\nin the extraction of spectral functions from lattice QCD simulations, based on\nBayesian inference and emphasize the importance of prior domain knowledge,\nvital to regularizing the otherwise ill-posed extraction task. With Bayesian\ninference allowing us to make explicit the uncertainty in both observations and\nin our prior knowledge, a systematic estimation of the total uncertainties in\nthe extracted spectral functions is nowadays possible. Two implementations of\nthe Bayesian Reconstruction (BR) method for spectral function extraction, one\nfor MAP point estimates and one based on an open access Monte-Carlo sampler are\nprovided.I will briefly touch on the use of machine learning for spectral\nfunction reconstruction and discuss some new insight it has brought to the\nBayesian community."
    },
    {
        "anchor": "FermiQCD: A tool kit for parallel lattice QCD applications: We present here the most recent version of FermiQCD, a collection of C++\nclasses, functions and parallel algorithms for lattice QCD, based on Matrix\nDistributed Processing. FermiQCD allows fast development of parallel lattice\napplications and includes some SSE2 optimizations for clusters of Pentium 4\nPCs.",
        "positive": "Radiative Decay Width of $J/\u03c8\\to \u03b3\u03b7_{(2)}$ from $N_f=2$\n  Lattice QCD: The large radiative production rate for pseudoscalar mesons in the $J/\\psi$\nradiative decay remains elusive. We present the first lattice QCD calculation\nof partial decay width of $J/\\psi$ radiatively decaying into $\\eta_{(2)}$, the\n$\\mathrm{SU(2)}$ flavor singlet pseudoscalar meson, which confirms QCD\n$\\mathrm{U_A(1)}$ anomaly enhancement to the coupling of gluons with flavor\nsinglet pseudoscalar mesons. The lattice simulation is carried out using\n$N_f=2$ lattice QCD gauge configurations at the pion mass $m_{\\pi} \\approx 350$\nMeV. In particular, the distillation method has been utilized to calculate\nlight quark loops. The results are reported here with the mass $m_{\\eta_{(2)}}=\n718(8)$ MeV and the decay width $\\Gamma(J/\\psi\\to\\gamma \\eta_{(2)})=0.385(45)$\nkeV. By assuming the dominance of $\\mathrm{U_A(1)}$ anomaly and flavor\nsinglet-octet mixing angle $\\theta=-24.5^\\circ$, the production rates for the\nphysical $\\eta$ and $\\eta'$ in $J/\\psi$ radiative decay are predicted to be\n$1.15(14)\\times 10^{-3}$ and $4.49(53)\\times 10^{-3}$, respectively, which\nagree well with the experimental measurement data. Our study manifests the\npotential of lattice QCD studies on the light hadron production in $J/\\psi$\nradiative decays."
    },
    {
        "anchor": "Theoretical Analysis of Acceptance Rates in Multigrid Monte Carlo: We analyze the kinematics of multigrid Monte Carlo algorithms by\ninvestigating acceptance rates for nonlocal Metropolis updates. With the help\nof a simple criterion we can decide whether or not a multigrid algorithm will\nhave a chance to overcome critial slowing down for a given model. Our method is\nintroduced in the context of spin models. A multigrid Monte Carlo procedure for\nnonabelian lattice gauge theory is described, and its kinematics is analyzed in\ndetail.",
        "positive": "Axial $U(1)$ symmetry at high temperature in 2-flavor lattice QCD: We investigate the axial $U(1)_A$ symmetry breaking above the critical\ntemperature in two-flavor lattice QCD. The ensembles are generated with\ndynamical M\\\"obius domain-wall or reweighted overlap fermions. The $U(1)_A$\nsusceptibility is extracted from the low-modes spectrum of the overlap Dirac\neigenvalues. We show the quark mass and temperature dependences of $U(1)_A$\nsusceptibility. Our results at $T=220 \\, \\mathrm{MeV}$ imply that the $U(1)_A$\nsymmetry is restored in the chiral limit. Its coincidence with vanishing\ntopological susceptibility is observed."
    },
    {
        "anchor": "Constraints on the two-flavor QCD phase diagram from imaginary chemical\n  potential: We review our knowledge of the phase diagram of QCD as a function of\ntemperature, chemical potential and quark masses. The presence of tricritical\nlines at imaginary chemical potential mu=i pi/3 T, with known scaling behaviour\nin their vicinity, puts constraints on this phase diagram, especially in the\ncase of two light flavors. We show first results in our project to determine\nthe finite-temperature behaviour in the two-flavour chiral limit.",
        "positive": "Fractional topological charges and the lowest Dirac modes: We introduce vortex configurations with fractional topological charges where\none unicolor or colorful intersection of two perpendicular vortex pairs\ncontributes to the topological charge of the configurations. Using both, the\noverlap and asqtad staggered fermion formulations, the lowest modes of the\nDirac operator on the noninteger $Q$ configurations are studied in the\nfundamental and adjoint representations. We analyze the behavior of the\nfundamental and adjoint fermions in the background of the topological charge\ncontributions of $|Q|=0.5$."
    },
    {
        "anchor": "Nucleon axial, tensor and scalar charges and $\u03c3$-terms in lattice\n  QCD: We determine the nucleon axial, scalar and tensor charges within lattice\nQuantum Chromodynamics including all contributions from valence and sea quarks.\n  We analyze three gauge ensembles simulated within the twisted mass\nformulation at approximately physical value of the pion mass. Two of these\nensembles are simulated with two dynamical light quarks and lattice spacing\n$a=0.094$~fm and the third with $a=0.08$~fm includes in addition the strange\nand charm quarks in the sea. After comparing the results among these three\nensembles, we quote as final values our most accurate analysis using the latter\nensemble.\n  For the nucleon isovector axial charge we find $1.286(23)$ in agreement with\nthe experimental value. We provide the flavor decomposition of the intrinsic\nspin $\\frac{1}{2}\\Delta\\Sigma^q$ carried by quarks in the nucleon obtaining for\nthe up, down, strange and charm quarks $\\frac{1}{2}\\Delta\\Sigma^{u}=0.431(8)$,\n$\\frac{1}{2}\\Delta\\Sigma^{d}=-0.212(8)$,\n$\\frac{1}{2}\\Delta\\Sigma^{s}=-0.023(4)$ and\n$\\frac{1}{2}\\Delta\\Sigma^{c}=-0.005(2)$, respectively. The corresponding values\nof the tensor and scalar charges for each quark flavor are also evaluated\nproviding valuable input for experimental searches for beyond the standard\nmodel physics.\n  In addition, we extract the nucleon $\\sigma$-terms and find for the light\nquark content $\\sigma_{\\pi N}=41.6(3.8)$~MeV and for the strange\n$\\sigma_{s}=45.6(6.2)$~MeV. The y-parameter that is used in phenomenological\nstudies we find $y=0.078(7)$.",
        "positive": "Towards a direct lattice calculation of m_d - m_u: We describe an independent method for determining the strong-isospin breaking\nmass parameter, 2delta = m_d - m_u, which utilizes the baryon spectrum. We use\na prudent partially quenched choice of splitting the valence quark masses\nsymmetrically about the light sea quark mass. This choice has the consequence\nof mitigating the most severe partial quenching artifacts. We also discuss the\nmost significant hurdle to this method which is determining the electromagnetic\nself-energy of the neutron-proton mass splitting, a challenge which lacks a\nsatisfactory answer. Despite these issues, the phenomenologically interesting\ndependence of m_n - m_p on delta can be determined."
    },
    {
        "anchor": "Volume dependence in 2+1 Yang-Mills theory: We present the results of an analysis of a 2+1 dimensional pure SU(N)\nYang-Mills theory formulated on a 2-dimensional spatial torus with non-trivial\nmagnetic flux. We focus on investigating the dependence of the electric-flux\nspectrum, extracted from Polyakov loop correlators, with the spatial size l,\nthe number of colours N, and the magnetic flux m. The size of the torus acts a\nparameter that allows to control the onset of non-perturbative effects. In the\nsmall volume regime, where perturbation theory holds, we derive the one-loop\nself-energy correction to the single-gluon spectrum, for arbitrary N and m. We\ndiscuss the transition from small to large volumes that has been investigated\nby means of Monte-Carlo simulations. We argue that the energy of electric flux\ne, for the lowest gluon momentum, depends solely on e/N and on the\ndimensionless variable x=lambda N l, with lambda the 't Hooft coupling. The\nvariable x can be interpreted as the dimensionless 't Hooft coupling for an\neffective box size given by Nl. This implies a version of reduction that allows\nto trade l by N without modifying the electric-flux energy.",
        "positive": "Responses of quark condensates to the chemical potential: The responses of quark condensates to the chemical potential, as a function\nof temperature T and chemical potential \\mu, are calculated within the\nNambu--Jona-Lasinio (NJL) model. We compare our results with those from the\nrecent lattice QCD simulations [QCD-TARO Collaboration, Nucl. Phys. B (Proc.\nSuppl.) 106, 462 (2002)]. The NJL model and lattice calculations show\nqualitatively similar behavior, and they will be complimentary ways to study\nhadrons at finite density. The behavior above T_c requires more elaborated\nanalyses."
    },
    {
        "anchor": "Non-perturbative insights into the spectral properties of QCD at finite\n  temperature: In quantum field theories at finite temperature spectral functions describe\nhow particle systems behave in the presence of a thermal medium. Although data\nfrom lattice simulations can in principle be used to determine spectral\nfunction characteristics, existing methods rely on the extraction of these\nquantities from temporal correlators, which requires one to circumvent an\nill-posed inverse problem. In these proceedings we report on a recent approach\nthat instead utilises the non-perturbative constraints imposed by field\nlocality to extract spectral function information directly from spatial\ncorrelators. In particular, we focus on the application of this approach to\nlattice QCD data of the spatial pseudo-scalar meson correlator in the\ntemperature range $220-960 \\, \\text{MeV}$, and outline why this data supports\nthe conclusion that there exists a distinct pion state above the chiral\npseudo-critical temperature $T_{\\!\\text{pc}}$.",
        "positive": "Neutral B meson mixing with static heavy and domain-wall light quarks: Neutral B meson mixing matrix elements and B meson decay constants are\ncalculated. Static approximation is used for b quark and domain-wall fermion\nformalism is employed for light quarks. The calculations are done on 2+1 flavor\ndynamical ensembles, whose lattice spacings are 0.086 fm and 0.11 fm with a\nfixed physical spatial volume of about (2.7 fm)^3. In the static quark action,\nlink-smearings are used to improve the signal-to-noise ratio. We employ two\nkinds of link-smearings and their results are combined in taking a continuum\nlimit. For the matching between the lattice and the continuum theory, one-loop\nperturbative calculations are used including O(a) improvements to reduce\ndiscretization errors. We obtain SU(3) braking ratio \\xi=1.222(60) in the\nstatic limit of b quark."
    },
    {
        "anchor": "Inclusive semi-leptonic decays from lattice QCD: We develop a method to compute inclusive semi-leptonic decay rate of hadrons\nfully non-perturbatively using lattice QCD simulations. The sum over all\npossible final states is achieved by a calculation of the forward-scattering\nmatrix elements on the lattice, and the phase-space integral is evaluated using\ntheir dependence on the time separation between two inserted currents. We\nperform a pilot lattice computation for the B_s -> X_c l nu decay with an\nunphysical bottom quark mass and compare the results with the corresponding OPE\ncalculation. The method to treat the inclusive processes on the lattice can be\napplied to other processes, such as the lepton-nucleon inelastic scattering.",
        "positive": "Critical Slowing Down of Cluster Algorithms for Ising Models Coupled to\n  2-d Gravity: We simulate single and multiple Ising models coupled to 2-d gravity using\nboth the Swendsen-Wang and Wolff algorithms to update the spins. We study the\nintegrated autocorrelation time and find that there is considerable critical\nslowing down, particularly in the magnetization. We argue that this is\nprimarily due to the local nature of the dynamical triangulation algorithm and\nto the generation of a distribution of baby universes which inhibits cluster\ngrowth."
    },
    {
        "anchor": "Phase Diagram of Wilson and Twisted Mass Fermions at finite isospin\n  chemical potential: Wilson Fermions with untwisted and twisted mass are widely used in lattice\nsimulations. Therefore one important question is whether the twist angle and\nthe lattice spacing affect the phase diagram. We briefly report on the study of\nthe phase diagram of QCD in the parameter space of the degenerate quark masses,\nisospin chemical potential, lattice spacing, and twist angle by employing\nchiral perturbation theory. Moreover we calculate the pion masses and their\ndependence on these four parameters.",
        "positive": "The Berry Phase and Monopoles in Gluodynamics: We introduce a gauge invariant definition of a monopole on the lattice. The\nconstruction is based on the observation that for each Wilson loop there exists\nan extra U(1) group which leaves the loop invariant. Since the lattice\nformulation utilizes the language of Wilson loops, the definition of the\nmonopole charge in terms of this plaquette dependent U(1) is gauge invariant.\nThe explicit construction of gauge invariant monopoles is presented both in\ncontinuum and on the lattice."
    },
    {
        "anchor": "Lattice QCD Constraints on the Fourth Mellin Moment of the Pion Light\n  Cone Distribution Amplitude using the HOPE method: The light-cone distribution amplitude (LCDA) of the pion contains information\nabout the parton momentum carried by the quarks and is an important theoretical\ninput for various predictions of exclusive processes at high energy, including\nthe pion electromagnetic form factor. Progress towards constraining the fourth\nMellin moment of the LCDA using the heavy-quark operator product expansion\n(HOPE) method is presented.",
        "positive": "Isospin breaking corrections to the HVP at the physical point: A determination of the hadronic vacuum polarization contribution to the\nanomalous magnetic moment of the muon from lattice QCD aiming at a precision of\n$1\\%$ requires to include isospin breaking corrections in the computation. We\npresent a lattice calculation of the QED and strong isospin breaking\ncorrections to the hadronic vacuum polarization with Domain Wall fermions. The\nresults are obtained using quark masses which are tuned such that pion and kaon\nmasses agree with their physical values including isospin breaking corrections."
    },
    {
        "anchor": "RHMC with Block Solvers and Multiple Pseudofermions: The dominant cost of most lattice QCD simulations is the inversion of the\nDirac operator required to calculate the force term in the RHMC update. One way\nto improve this situation is to use multiple pseudofermions, which reduces the\nsize and variance of this force and hence allows a larger integration step size\nto be used. This means fewer force term calculations are required, but at the\ncost of having to invert the Dirac operator for each pseudofermion field. This\nbottleneck can be addressed: recently there has been renewed interest in the\nuse of block Krylov solvers, which can solve multiple right hand side vectors\nwith significantly fewer iterations than are required if each vector is solved\nusing a separate Krylov solver. We combine these two ideas, achieving a\nsignificant speed-up of RHMC lattice QCD simulations.",
        "positive": "Does Conformal Quantum Field Theory Describe the Continuum Limits of 2D\n  Spin Models with Continuous Symmetry?: It is generally taken for granted that two-dimensional critical phenomena can\nbe fully classified by the well known two-dimensional (rational) conformal\nquantum field theories (CQFTs). In particular it is believed that in models\nwith a continuous symmetry characterized by a Lie group $G$ the continuum\ntheory enjoys an enhanced symmetry $G\\times G$ due to the decoupling of right\nand left movers. In this letter we review the conventional arguments leading to\nthis conclusion, point out two gaps and provide a conterexample. Nevertheless\nwe justify in the end the conventional conclusions by additional arguments."
    },
    {
        "anchor": "Multicanonical simulation of 3D dynamical triangulation model and a new\n  phase structure: We apply the multicanonical technique to the three dimensional dynamical\ntriangulation model, which is known to exhibit a first order phase transition\nwith the Einstein-Hilbert action. We first clarify the first order nature of\nthe phase transition with the Einstein-Hilbert action in several ways including\na high precision finite size scaling analysis. We then add a new local term to\nthe action and confirm the conjecture made through the MCRG technique that the\nline of the first order phase transition extends to the expanded phase diagram,\nending at a point. Fractal dimension at the end point is measured to be around\nthree up to the present size.",
        "positive": "Precision calculations of nucleon charges $g_A$, $g_S$, $g_T$: We present a detailed analysis of statistical and systematic errors in the\ncalculation of matrix elements of iso-vector scalar, axial and tensor charges\nbetween a neutron and a proton state. These analyses are being done on\ndynamical $N_f=2+1+1$ HISQ configurations generated by the MILC Collaboration\nusing valence clover fermions. Using ensembles at three values of the lattice\nspacing ($a=0.12,\\ 0.09,$ and $0.06$ fm) and three values of the quark mass\n($M_\\pi \\approx 310,\\ 220$ and $130$ MeV) we find that the estimates of the\ntensor charge are stable and it can be extracted with $5\\%$ precision with\nO(10,000) measurements. We also find that higher statistics are needed to\nresolve the various uncertainties in the calculation of $g_A$ and improve the\nsignal in $g_S$, which with present data has large errors. A brief status\nreport on the mixing and renormalization of novel operators contributing to\nnEDM is also given."
    },
    {
        "anchor": "Percolation properties of the 2D Heisenberg model: We analyze the percolation properties of certain clusters defined on\nconfigurations of the 2--dimensional Heisenberg model. We find that, given any\ndirection \\vec{n} in O(3) space, the spins almost perpendicular to \\vec{n} form\na percolating cluster. This result gives indications of how the model can avoid\na previously conjectured Kosterlitz-Thouless phase transition at finite\ntemperature T.",
        "positive": "An estimate for the thermal photon rate from lattice QCD: We estimate the production rate of photons by the quark-gluon plasma in\nlattice QCD. We propose a new correlation function which provides better\ncontrol over the systematic uncertainty in estimating the photon production\nrate at photon momenta in the range {\\pi}T/2 to 2{\\pi}T. The relevant Euclidean\nvector current correlation functions are computed with $N_{\\mathrm f}$ = 2\nWilson clover fermions in the chirally-symmetric phase. In order to estimate\nthe photon rate, an ill-posed problem for the vector-channel spectral function\nmust be regularized. We use both a direct model for the spectral function and a\nmodel-independent estimate from the Backus-Gilbert method to give an estimate\nfor the photon rate."
    },
    {
        "anchor": "Master Wilson loop operators in large-N lattice QCD$_2$: An explicit solution is found for the most general independent correlation\nfunctions in lattice QCD$_2$ with Wilson action. The large-$N$ limit of these\ncorrelations may be used to reconstruct the eigenvalue distributions of Wilson\nloop operators for arbitrary loops. Properties of these spectral densities are\ndiscussed in the region $\\beta<\\beta_c={1\\over 2}$.",
        "positive": "The gradient flow at higher orders in perturbation theory: Various results for higher-order perturbative calculations in the\ngradient-flow formalism are reviewed, including the gradient-flow beta function\nand the small-flow-time expansion of the hadronic vacuum polarization and the\nenergy-momentum tensor. In addition, the strategy of regions is outlined in\norder to obtain systematic expansions of gradient-flow integrals, for example\nat large and small flow times."
    },
    {
        "anchor": "Investigating the Sharpe-Singleton scenario on the lattice by direct\n  eigenvalue computation: We investigate the phase structure of lattice QCD with dynamical Wilson\nfermions. Wilson chiral perturbation theory predicts that the Aoki phase and\nthe Sharpe-Singleton scenario manifest themselves in very distinct behavior of\nthe Wilson Dirac eigenvalue spectrum. To test this prediction we perform a\ndirect calculation of the eigenvalues of the non-Hermitian Wilson Dirac\noperator in dynamical lattice simulations. Moreover, we demonstrate an\nunexpected quark mass dependence on the shape of the eigenvalue distribution in\nthe positive quark mass side.",
        "positive": "Exact relation of lattice and continuum parameters in three-dimensional\n  SU(2)+Higgs theories: The essential features of the high-temperature electroweak phase transition\nare contained in a three-dimensional super-renormalizable effective field\ntheory. We calculate the exact counterterms needed for lattice simulations of\nthe SU(2)-part of this theory. Scalar fields in both fundamental and adjoint\nrepresentations are included. The three-dimensional U(1)+Higgs theory is also\ndiscussed."
    },
    {
        "anchor": "Ideal topological gas in the high temperature phase of SU(3) gauge\n  theory: We show that the nature of the topological fluctuations in $SU(3)$ gauge\ntheory changes drastically at the finite temperature phase transition. Starting\nfrom temperatures right above the phase transition topological fluctuations\ncome in well separated lumps of unit charge that form a non-interacting ideal\ngas. Our analysis is based on a novel method to count not only the net\ntopological charge, but also separately the number of positively and negatively\ncharged lumps in lattice configurations using the spectrum of the overlap Dirac\noperator. This enables us to determine the joint distribution of the number of\npositively and negatively charged topological objects, and we find this\ndistribution to be consistent with that of an ideal gas of unit charged\ntopological objects.",
        "positive": "I=2 $\u03c0\u03c0$ Scattering Phase Shift with two Flavors of $O(a)$ Improved\n  Dynamical Quarks: We present a lattice QCD calculation of phase shift including the chiral and\ncontinuum extrapolations in two-flavor QCD. The calculation is carried out for\nI=2 S-wave $\\pi\\pi$ scattering. The phase shift is evaluated for two momentum\nsystems, the center of mass and laboratory systems, by using the finite volume\nmethod proposed by L\\\"uscher in the center of mass system and its extension to\ngeneral systems by Rummukainen and Gottlieb. The measurements are made at three\ndifferent bare couplings $\\beta = 1.80$, 1.95 and 2.10 using a renormalization\ngroup improved gauge and a tadpole improved clover fermion action, and\nemploying a set of configurations generated for hadron spectroscopy in our\nprevious work. The illustrative values we obtain for the phase shift in the\ncontinuum limit are $\\delta$(deg.) $= - 3.50(64)$, $ - 9.5(30)$ and $ -\n16.9(64)$ for $\\sqrt{s}({\\rm GeV})$ $=0.4$, $ 0.6$ and $ 0.8$, which are\nconsistent with experiment."
    },
    {
        "anchor": "The Yang Lee Edge Singularity on Feynman Diagrams: We investigate the Yang-Lee edge singularity on non-planar random graphs,\nwhich we consider as the Feynman Diagrams of various d=0 field theories, in\norder to determine the value of the edge exponent.\n  We consider the hard dimer model on phi3 and phi4 random graphs to test the\nuniversality of the exponent with respect to coordination number, and the Ising\nmodel in an external field to test its temperature independence. The results\nhere for generic (``thin'') random graphs provide an interesting counterpoint\nto the discussion by Staudacher of these models on planar random graphs.",
        "positive": "Free energy of static quarks and the renormalized Polyakov loop in full\n  QCD: We present results from a detailed study of singlet free energies in full QCD\nwith realistic quark masses. An improved scheme for the non-perturbative\nrenormalization of the Polyakov loop is used and we compare its temperature\ndependence for QCD with different flavor content. We also analyze screening\nmasses extracted from singlet free energies at various temperatures close to\nand above the QCD transition temperature. We conclude that the temperature\ndependence of screening masses is well described by perturbation theory up to a\nnon-perturbative pre-factor. An effective running coupling has been determined\nfor all temperature values giving additional insight into screening phenomena\nat high temperature."
    },
    {
        "anchor": "Topological Data Analysis of Monopoles in $U(1)$ Lattice Gauge Theory: In $4$-dimensional pure compact $U(1)$ lattice gauge theory, we analyse\ntopological aspects of the dynamics of monopoles across the deconfinement phase\ntransition. We do this using tools from Topological Data Analysis (TDA). We\ndemonstrate that observables constructed from the zeroth and first homology\ngroups of monopole current networks may be used to quantitatively and robustly\nlocate the critical inverse coupling $\\beta_{c}$ through finite-size scaling.\nOur method provides a mathematically robust framework for the characterisation\nof topological invariants related to monopole currents, putting on firmer\nground earlier investigations. Moreover, our approach can be generalised to the\nstudy of Abelian monopoles in non-Abelian gauge theories.",
        "positive": "Review on Hadron Spectroscopy: I review some of the lattice results on spectroscopy and resonances in the\npast years. For the conventional hadron spectrum computations, focus has been\nput on the isospin breaking effects, QED effects, and simulations near the\nphysical pion mass point. I then go through several single-channel scattering\nstudies within L\\\"uscher formalism, a method that has matured over the past few\nyears. The topics cover light mesons and also the charmed mesons, with the\nlatter case intimately related to the recently discovered exotic $XYZ$\nparticles. Other possible related formalisms that are available on the market\nare also discussed."
    },
    {
        "anchor": "Nucleon structure in the chiral regime with domain wall fermions on an\n  improved staggered sea: Moments of unpolarized, helicity, and transversity distributions,\nelectromagnetic form factors, and generalized form factors of the nucleon are\npresented from a preliminary analysis of lattice results using pion masses down\nto 359 MeV. The twist two matrix elements are calculated using a mixed action\nof domain wall valence quarks and asqtad staggered sea quarks and are\nrenormalized perturbatively. Several observables are extrapolated to the\nphysical limit using chiral perturbation theory. Results are compared with\nexperimental moments of quark distributions and electromagnetic form factors\nand phenomenologically determined generalized form factors, and the\nimplications on the transverse structure and spin content of the nucleon are\ndiscussed.",
        "positive": "The SF running coupling with four flavours of staggered quarks: In order to study the running coupling in four-flavour QCD, we review the\nset-up of the Schr\\\"odinger functional (SF) with staggered quarks. Staggered\nquarks require lattices which, in the usual counting, have even spatial lattice\nextent $L/a$ while the time extent $T/a$ must be odd. Setting $T=L$ is\ntherefore only possible up to ${\\rm O}(a)$, which introduces different cutoff\neffects already in the pure gauge theory. We re-define the SF such as to cope\nwith this situation and determine the corresponding classical background field.\nA perturbative calculation yields the coefficient of the pure gauge ${\\rm\nO}(a)$ boundary counterterm to one-loop order."
    },
    {
        "anchor": "Estimates of critical quantities from an expansion in mass: Ising model\n  on the simple cubic lattice: In the Ising model on the simple cubic lattice, we describe the inverse\ntemperature $\\beta$ and other quantities relevant for the computation of\ncritical quantities in terms of a dimensionless squared mass $M$. The critical\nbehaviors of those quantities are represented by the linear differential\nequations with constant coefficients which are related to critical exponents.\nWe estimate the critical temperature and exponents via an expansion in the\ninverse powers of the mass under the use of $\\delta$-expansion. The critical\ninverse temperature $\\beta_{c}$ is estimated first in unbiased manner and then\ncritical exponents are also estimated in biased and unbiased self-contained way\nincluding $\\omega$, the correction-to-scaling exponent, $\\nu$, $\\eta$ and\n$\\gamma$.",
        "positive": "Nonperturbative Renormalization in the RI-SMOM Scheme and Gribov\n  Uncertainty in the RI-MOM Scheme for Staggered Bilinears: We present results of renormalization factors for bilinear operators obtained\nusing the nonperturbative renormalization method (NPR) in the RI-SMOM schemes.\nThe operators are constructed using HYP staggered quarks on the MILC asqtad\nlattice ($N_f=2+1$). We compare results in the RI-SMOM schemes with those in\nthe RI-MOM scheme for the $V\\otimes S$ and $S\\otimes S$ operators. Since we use\nLandau gauge fixing, we study the effect of Gribov ambiguity on the wave\nfunction renormalization $Z_q$ in the RI-MOM scheme. We find that the Gribov\nuncertainty is negligibly small for $Z_q$ in the RI-MOM scheme."
    },
    {
        "anchor": "Abelian dominance and adjoint sources in lattice QCD: Certain properties of maximal abelian projection are derived which suggest\nthat the fundamental and adjoint SU(2) string tensions are reproduced by singly\nand doubly charged abelian Wilson loops, respectively. Thus, abelian dominance,\nwhich has been observed for color sources (quarks) in the fundamental\nrepresentation, can be extended to higher representations. Numerical evidence\nin support of this conjecture also for adjoint quarks is presented. The\ndifference between maximal abelian and local projections is elucidated and the\nrole of non-Wilson-like terms in the effective abelian action is discussed.",
        "positive": "New canonical and grand canonical DoS techniques for finite density\n  lattice QCD: We discuss two new DoS approaches for finite density lattice QCD. The paper\nextends a recent presentation of the new techniques based on Wilson fermions,\nwhile here we now discuss and test the case of finite density QCD with\nstaggered fermions. The first of our two approaches is based on the canonical\nformulation where observables at a fixed net quark number $N$ are obtained as\nFourier moments of the vacuum expectation values at imaginary chemical\npotential $\\theta$. We treat the latter as densities which can be computed with\nthe recently developed FFA method. The second approach is based on a direct\ngrand canonical evaluation after rewriting the QCD partition sum in terms of a\nsuitable pseudo-fermion representation. In this form the imaginary part of the\npseudo-fermion action can be identified and the corresponding density may again\nbe computed with FFA. We develop the details of the two approaches and discuss\nsome exploratory first tests for the case of free fermions where reference\nresults for assessing the new techniques may be obtained from Fourier\ntransformation."
    },
    {
        "anchor": "Improved Perturbation Theory for Improved Lattice Actions: We study a systematic improvement of perturbation theory for gauge fields on\nthe lattice; the improvement entails resumming, to all orders in the coupling\nconstant, a dominant subclass of tadpole diagrams.\n  This method, originally proposed for the Wilson gluon action, is extended\nhere to encompass all possible gluon actions made of closed Wilson loops; any\nfermion action can be employed as well. The effect of resummation is to replace\nvarious parameters in the action (coupling constant, Symanzik coefficients,\nclover coefficient) by ``dressed'' values; the latter are solutions to certain\ncoupled integral equations, which are easy to solve numerically.\n  Some positive features of this method are: a) It is gauge invariant, b) it\ncan be systematically applied to improve (to all orders) results obtained at\nany given order in perturbation theory, c) it does indeed absorb in the dressed\nparameters the bulk of tadpole contributions.\n  Two different applications are presented: The additive renormalization of\nfermion masses, and the multiplicative renormalization Z_V (Z_A) of the vector\n(axial) current. In many cases where non-perturbative estimates of\nrenormalization functions are also available for comparison, the agreement with\nimproved perturbative results is significantly better as compared to results\nfrom bare perturbation theory.",
        "positive": "Decoupling of charm beyond leading order: We study the effective theory of decoupling of a charm quark at low energies.\nWe do this by simulating a model, QCD with two mass-degenerate charm quarks. At\nleading order the effective theory is a pure gauge theory. By computing ratios\nof hadronic scales we have direct access to the power corrections in the\neffective theory. We show that these corrections follow the expected leading\nbehavior, which is quadratic in the inverse charm quark mass."
    },
    {
        "anchor": "An anisotropic preconditioning for the Wilson fermion matrix on the\n  lattice: A preconditioning for the Wilson fermion matrix on the lattice is defined\nwhich is particularly suited to the case when the temporal lattice spacing is\nmuch smaller than the spatial one. Details on the implementation of the scheme\nare given. The method is tested in numerical studies of QCD on anisotropic\nlattices.",
        "positive": "Distributions of individual Dirac eigenvalues for QCD at non-zero\n  chemical potential: RMT predictions and lattice results: For QCD at non-zero chemical potential $\\mu$, the Dirac eigenvalues are\nscattered in the complex plane. We define a notion of ordering for individual\neigenvalues in this case and derive the distributions of individual eigenvalues\nfrom random matrix theory (RMT). We distinguish two cases depending on the\nparameter $\\alpha=\\mu^2 F^2 V$, where $V$ is the volume and $F$ is the familiar\nlow-energy constant of chiral perturbation theory. For small $\\alpha$, we use a\nFredholm determinant expansion and observe that already the first few terms\ngive an excellent approximation. For large $\\alpha$, all spectral correlations\nare rotationally invariant, and exact results can be derived. We compare the\nRMT predictions to lattice data and in both cases find excellent agreement in\nthe topological sectors $\\nu=0,1,2$."
    },
    {
        "anchor": "Finite size scaling of conformal theories in the presence of a\n  near-marginal operator: The slowly evolving gauge coupling of gauge-fermion systems near the\nconformal window makes numerical investigations of these models challenging. We\nconsider finite size scaling and show that this often used technique leads to\ninconsistent results if the leading order scaling corrections are neglected.\nWhen the corrections are included the results become consistent not only\nbetween different operators but even when data obtained at different gauge\ncouplings or with different lattice actions are combined. Our results indicate\nthat the SU(3) 12-fermion system is conformal with mass anomalous dimension\n$\\gamma_m=0.235(15)$.",
        "positive": "Heavy-Baryon Spectroscopy from Lattice QCD: We use a four-dimensional lattice calculation of the full-QCD (quantum\nchromodynamics, the non-abliean gauge theory of the strong interactions of\nquarks and gluons) path integrals needed to determine the masses of the charmed\nand bottom baryons. In the charm sector, our results are in good agreement with\nexperiment within our systematics, except for the spin-1/2 $\\Xi_{cc}$, for\nwhich we found the isospin-averaged mass to be $\\Xi_{cc}$ to be\n$3665\\pm17\\pm14^{+0}_{-78}$ MeV. We predict the mass of the (isospin-averaged)\nspin-1/2 $\\Omega_{cc}$ to be $3763\\pm19\\pm26^{+13}_{-79}$ {MeV}. In the bottom\nsector, our results are also in agreement with experimental observations and\nother lattice calculations within our statistical and systematic errors. In\nparticular, we find the mass of the $\\Omega_b$ to be consistent with the recent\nCDF measurement. We also predict the mass for the as yet unobserved\n$\\Xi^\\prime_b$ to be 5955(27) MeV."
    },
    {
        "anchor": "Stochastic method with low mode substitution for nucleon isovector\n  matrix elements: We introduce a stochastic sandwich method with low-mode substitution to\nevaluate the connected three-point functions. The isovector matrix elements of\nthe nucleon for the axial-vector coupling $g_A^3$, scalar couplings $g_S^3$ and\nthe quark momentum fraction $\\langle x\\rangle_{u -d}$ are calculated with\noverlap fermion on 2+1 flavor domain-wall configurations on a $24^3 \\times 64$\nlattice at $m_{\\pi} = 330$ MeV with lattice spacing $a = 0.114$ fm.",
        "positive": "Witten's SU(2) anomaly on the lattice: Witten's anomaly for SU(2) with a single I=1/2 Weyl fermion in four dimension\nis shown to be reproduced by the lattice overlap. The mechanism is based on\nBerry's phase, and on the analyticity of the matrix $H$ by which the overlap is\ndefined."
    },
    {
        "anchor": "Low-energy Scattering of $(D^{*}\\bar{D}^{*})^\\pm$ System and the\n  Resonance-like Structure $Z_c(4025)$: In this paper, low-energy scattering of the $(D^{*}\\bar{D}^{*})^\\pm$ meson\nsystem is studied within L\\\"uscher's finite-size formalism using $N_{f}=2$\ntwisted mass gauge field configurations. With three different pion mass values,\nthe $s$-wave threshold scattering parameters, namely the scattering length\n$a_0$ and the effective range $r_0$, are extracted in $J^P=1^+$ channel. Our\nresults indicate that, in this particular channel, the interaction between the\ntwo vector charmed mesons is weakly repulsive in nature hence do not support\nthe possibility of a shallow bound state for the two mesons, at least for the\npion mass values being studied. This study provides some useful information on\nthe nature of the newly discovered resonance-like structure $Z_c(4025)$\nobserved in various experiments.",
        "positive": "Non-perturbative study of QCD correlators: This PhD dissertation is devoted to a non-perturbative study of QCD\ncorrelators. The main tool that we use is lattice QCD. We concentrated our\nefforts on the study of the main correlators of the pure Yang - Mills theory in\nthe Landau gauge, namely the ghost and the gluon propagators. We are\nparticularly interested in determining the $\\Lqcd$ parameter. It is extracted\nby means of perturbative predictions available up to NNNLO. The related topic\nis the influence of non-perturbative effects that show up as appearance of\npower-corrections to the low-momentum behaviour of the Green functions. A new\nmethod of removing these power corrections allows a better estimate of $\\Lqcd$.\nOur result is $\\Lambda^{n_f=0}_{\\ms} = 269(5)^{+12}_{-9}$ MeV. Another question\nthat we address is the infrared behaviour of Green functions, at momenta of\norder and below $\\Lqcd$. At low energy the momentum dependence of the\npropagators changes considerably, and this is probably related to confinement.\nThe lattice approach allows to check the predictions of analytical methods\nbecause it gives access to non-perturbative correlators. According to our\nanalysis the gluon propagator is finite and non-zero at vanishing momentum, and\nthe power-law behaviour of the ghost propagator is the same as in the free\ncase."
    },
    {
        "anchor": "First Nonperturbative Test of a Relativistic Heavy Quark Action in\n  Quenched Lattice QCD: We perform a numerical test of a relativistic heavy quark(RHQ) action,\nrecently proposed by Tsukuba group, in quenched lattice QCD at $a\\simeq 0.1$\nfm. With the use of the improvement parameters previously determined at\none-loop level for the RHQ action, we investigate a restoration of rotational\nsymmetry for heavy-heavy and heavy-light meson systems around the charm quark\nmass. We focused on two quantities, the meson dispersion relation and the\npseudo-scalar meson decay constants. It is shown that the RHQ action\nsignificantly reduces the discretization errors due to the charm quark mass. We\nalso calculate the S-state hyperfine splittings for the charmonium and\ncharmed-strange mesons and the $D_s$ meson decay constant. The remaining\ndiscretization errors in the physical quantities are discussed.",
        "positive": "Flavor Singlet Axial Coupling of the Proton - An Updated Analysis: We present a combined analysis of SESAM and TxL data for the flavor singlet\naxial coupling G_A^1 of the proton, which is very helpful to stabilize the\ndisconnected signals at small quark masses.\n  From connected and disconnected contributions we use the tadpole improved\nrenormalization constant Z_A and obtain G_A^1=0.21(12)."
    },
    {
        "anchor": "QCD at finite chemical potential with six time slices: We investigate the Taylor expansion of the baryon number susceptibility, and\nhence, pressure, in a series in the baryon chemical potential (mu_B) through a\nlattice simulation with light dynamical staggered quarks at a finer lattice\ncutoff a=1/6T. We determine the QCD cross over coupling at mu_B=0. We find the\nradius of convergence of the series at various temeperatures, and bound the\nlocation of the QCD critical point to be T^E/T_c = 0.94 and mu_B^E/T < 1.8. We\nalso investigate the extrapolation of various susceptibilities and linkages to\nfinite chemical potential.",
        "positive": "The role of center vortices in Gribov's confinement scenario: The connection of Gribov's confinement scenario in Coulomb gauge with the\ncenter vortex picture of confinement is investigated. For this purpose we\nassume a vacuum wave functional which models the infrared properties of the\ntheory and in particular shows strict confinement, i.e. an area law of the\nWilson loop. We isolate the center vortex content of this wave functional by\nstandard lattice methods and investigate their contributions to various static\npropagators of the Hamilton approach to Yang-Mills theory in Coulomb gauge. We\nfind that the infrared properties of these quantities, in particular the\ninfrared divergence of the ghost form factor, are dominated by center vortices."
    },
    {
        "anchor": "Application of Multicanonical Multigrid Monte Carlo Method to the\n  Two-Dimensional $\u03c6^4$-Model: Autocorrelations and Interface Tension: We discuss the recently proposed multicanonical multigrid Monte Carlo method\nand apply it to the scalar $\\phi^4$-model on a square lattice. To investigate\nthe performance of the new algorithm at the field-driven first-order phase\ntransitions between the two ordered phases we carefully analyze the\nautocorrelations of the Monte Carlo process. Compared with standard\nmulticanonical simulations a real-time improvement of about one order of\nmagnitude is established. The interface tension between the two ordered phases\nis extracted from high-statistics histograms of the magnetization applying\nhistogram reweighting techniques.",
        "positive": "Strong coupling expansion for finite temperature Yang-Mills theory in\n  the confined phase: We perform euclidean strong coupling expansions for Yang Mills theory on the\nlattice at finite temperature. After setting up the formalism for general\nSU(N), we compute the first few terms of the series for the free energy density\nand the lowest screening mass in the case of SU(2). To next-to-leading order\nthe free energy series agrees with that of an ideal gas of glueballs. This\ndemonstrates that in the confined phase the quasi-particles indeed correspond\nto the T=0 hadron excitations, as commonly assumed in hadron resonance gas\nmodels. Our result also fixes the lower integration constant for Monte Carlo\ncalculations of the thermodynamic pressure via the integral method. In accord\nwith Monte Carlo results, we find screening masses to be nearly temperature\nindependent in the confined phase. This and the exponential smallness of the\npressure can be understood as genuine strong coupling effects. Finally, we\nanalyse Pade approximants to estimate the critical couplings of the phase\ntransition, which for our short series are only ~25% accurate. However, up to\nthese couplings the equation of state agrees quantitatively with numerical\nresults on N_t=1-4 lattices."
    },
    {
        "anchor": "Lattice QCD investigation of the structure of the $a_0(980)$ meson: We investigate the quark content of the scalar meson $a_0(980)$ using lattice\nQCD. To this end we consider correlation functions of six different two- and\nfour-quark interpolating fields. We evaluate all diagrams, including diagrams,\nwhere quarks propagate within a timeslice, e.g. with closed quark loops. We\ndemonstrate that diagrams containing such closed quark loops have a drastic\neffect on the final results and, thus, may not be neglected. Our analysis shows\nthat in addition to the expected spectrum of two-meson scattering states there\nis an additional energy level around the two-particle thresholds of $K +\n\\bar{K}$ and $\\eta + \\pi$. This additional state, which is a candidate for the\n$a_0(980)$ meson, couples to a quark-antiquark as well as to a\ndiquark-antidiquark interpolating field, indicating that it is a superposition\nof an ordinary $\\bar{q} q$ and a tetraquark structure. The analysis is\nperformed using AMIAS, a novel statistical method based on the sampling of all\npossible spectral decompositions of the considered correlation functions, as\nwell as solving standard generalized eigenvalue problems.",
        "positive": "A simple derivation of the Overlap Dirac Operator: We derive the vector-like four dimensional overlap Dirac operator starting\nfrom a five dimensional Dirac action in the presence of a delta-function\nspace-time defect. The effective operator is obtained by first integrating out\nall the fermionic modes in the fixed gauge background, and then identifying the\ncontribution from the localized modes as the determinant of an operator in one\ndimension less. We define physically relevant degrees of freedom on the defect\nby introducing an auxiliary defect-bound fermion field and integrating out the\noriginal five dimensional bulk field."
    },
    {
        "anchor": "Ising-link Quantum Gravity: We define a simplified version of Regge quantum gravity where the link\nlengths can take on only two possible values, both always compatible with the\ntriangle inequalities. This is therefore equivalent to a model of Ising spins\nliving on the links of a regular lattice with somewhat complicated, yet local\ninteractions. The measure corresponds to the natural sum over all 2^links\nconfigurations, and numerical simulations can be efficiently implemented by\nmeans of look-up tables. In three dimensions we find a peak in the ``curvature\nsusceptibility'' which grows with increasing system size. However, the value of\nthe corresponding critical exponent as well as the behavior of the curvature at\nthe transition differ from that found by Hamber and Williams for the Regge\ntheory with continuously varying link lengths.",
        "positive": "Multicanonical reweighting for the QCD topological susceptibility: We introduce a reweighting technique which allows for a continuous sampling\nof temperatures in a single simulation and employ it to compute the temperature\ndependence of the QCD topological susceptibility at high temperatures. The\nmethod determines the ratio of susceptibility between any two temperatures\nwithin the explored temperature range. We find that the results from the method\nagree with our previous determination and that it is competitive with but not\nbetter than existing methods of determining the temperature derivative of the\nsusceptibility. The method may also be useful in exploring the temperature\ndependence of other thermodynamical observables in QCD in a continuous way."
    },
    {
        "anchor": "Hadronic physics from a Wilson fermion mixed-action approach: Charm\n  quark mass and $D_{(s)}$ meson decay constants: We present our first set of results for charm physics, using the mixed-action\nsetup introduced in a companion paper. Maximally twisted Wilson valence\nfermions are used on a sea of non-perturbatively $O(a)$-improved Wilson\nfermions, made up by CLS $N_{\\mathrm{\\scriptstyle f}}=2+1$ ensembles. Our\ncharm-sector observables are free from $O(am_c)$ discretisation effects,\nwithout need of tuning any improvement coefficient, and show continuum-limit\nscaling properties consistent with leading cutoff effects of $O(a^2)$. We\nconsider a subset of CLS ensembles -- including four values of the lattice\nspacing and pion masses down to 200 MeV -- allowing to take the continuum limit\nand extrapolate to the physical pion mass. A number of techniques are\nincorporated in the analysis in order to estimate the systematic uncertainties\nof our results for the charm quark mass and the $D_{(s)}$-meson decay\nconstants. This first study of observables in the charm sector, where the\nemphasis has been on the control of the methodology, demonstrates the potential\nof our setup to achieve high-precision results.",
        "positive": "Current Status of Indirect CP Violation in Neutral Kaon System: In the standard model (SM), the CP violation is introduced through a single\nphase in the CKM matrix. The neutral kaon system is one of the most precise\nchannels to test how the SM theory describes the experiment data such as\n$\\epsilon_K$ accurately. The indirect CP violation is parametrized into\n$\\epsilon_{K}$, which can be calculated directly using lattice QCD. In this\ncalculation, the largest uncertainty comes from two sources: one is $\\hat{B}_K$\nand the other is $V_{cb}$. We use the lattice results of $\\hat{B}_K$ and\nexclusive $V_{cb}$ to calculate the theoretical estimate of $\\epsilon_K$, which\nturns out to be $3.1\\sigma$ away from its experimental value. Here, the error\nis evaluated using the standard error propagation method."
    },
    {
        "anchor": "Machine learning action parameters in lattice quantum chromodynamics: Numerical lattice quantum chromodynamics studies of the strong interaction\nare important in many aspects of particle and nuclear physics. Such studies\nrequire significant computing resources to undertake. A number of proposed\nmethods promise improved efficiency of lattice calculations, and access to\nregions of parameter space that are currently computationally intractable, via\nmulti-scale action-matching approaches that necessitate parametric regression\nof generated lattice datasets. The applicability of machine learning to this\nregression task is investigated, with deep neural networks found to provide an\nefficient solution even in cases where approaches such as principal component\nanalysis fail. The high information content and complex symmetries inherent in\nlattice QCD datasets require custom neural network layers to be introduced and\npresent opportunities for further development.",
        "positive": "Remnants of large-$N_\\mathrm{f}$ inhomogeneities in the 2-flavor chiral\n  Gross-Neveu model: We study the $(1+1)$-dimensional chiral Gross-Neveu model on the lattice. At\nfinite density, analytic mean-field results predict the existence of\ninhomogeneous condensates breaking both chiral symmetry and spacetime\nsymmetries spontaneously. We investigate the fate of these inhomogeneities for\ntwo flavors and find remnant structural order, albeit with a decaying\namplitude. We also map out phase diagrams in the plane spanned by the chemical\npotential and temperature for different lattice spacings and physical volumes.\nFinally, we comment on the interpretation of our results in the light of\nvarious no-go theorems."
    },
    {
        "anchor": "Charm semileptonic decays and |V_{cs(d)}| from heavy clover quarks and\n  2+1 flavor asqtad staggered ensembles: By combining experimentally measured partial branching fractions for the\nsemileptonic decays D to K l nu and D to pi l nu with lattice calculations of\nthe form factors f_+^{D to K}(q^2) and f_+^{D to pi}(q^2), one can extract the\nCKM matrix elements |V_{cs}| and |V_{cd}|. We are calculating the form factors\nby using Fermilab charm and asqtad staggered light and strange quarks on 2+1\nflavor asqtad staggered ensembles generated by the MILC Collaboration. We vary\nthe light valence quark masses from 0.4m_s to 0.05m_s (m_s is the strange\nsea-quark mass), and the lattice spacings, from about 0.12 fm to about 0.045\nfm. We extrapolate to the physical light-quark mass and the continuum limit\nusing heavy-light meson staggered chiral perturbation theory about the SU(2)\nand SU(3) limits, compare the resulting (preliminary) form factor shapes with\nexperiment, and discuss our errors.",
        "positive": "Path Integrals and Voronin's Theorem on the Universality of the Riemann\n  Zeta Function: We explore a new approach to the path integral for a latticized quantum\ntheory. This talk is based on work with N. Khuri and H. Ren."
    },
    {
        "anchor": "The masses of the mesons and baryons. Part II. The Standing Wave Model: In order to explain the empirical integer multiple rule for the stable mesons\nand baryons presented in the preceding paper we assume that the particles are\nheld together in a cubic nuclear lattice. This is a novel approach to the\nparticles, based on the fact that the range of the weak nuclear force is only a\nthousandth of the diameter of the nucleon, and that the crystals are the\nbest-known macroscopic bodies held together by a microscopic force. We\ninvestigate the standing waves in a cubic nuclear lattice. From the frequency\ndistribution of the waves follows that the masses of the $\\gamma$-branch\nparticles are integer multiples of $m(\\pi^0)$. We show that each particle has\nautomatically an antiparticle. Assuming that the energy of the oscillations is\ndetermined by Planck's formula for the energy of a linear oscillator, it turns\nout that the $\\pi^0$ meson and the other members of the $\\gamma$-branch are\nlike cubic black bodies filled with plane, standing electromagnetic waves. Our\nstanding wave model explains the integer multiple rule of the masses of the\nneutral mesons and baryons of the $\\gamma$-branch and uses nothing else but\nphotons. Our results justify the cubic lattice assumption.",
        "positive": "Two--dimensional lattice Gross--Neveu model with Wilson twisted mass\n  fermions: We study the two-dimensional lattice Gross--Neveu model with Wilson twisted\nmass fermions in order to explore the phase structure in this setup. In\nparticular, we investigate the behaviour of the phase transitions found earlier\nwith standard Wilson fermions as a function of the twisted mass parameter\n$\\mu$. We find that qualitatively the dependence of the phase transitions on\n$\\mu$ is very similar to the case of lattice QCD."
    },
    {
        "anchor": "Nuclear Parity Violation from Lattice QCD: The electroweak interaction at the level of quarks and gluons are well\nunderstood from precision measurements in high energy collider experiments.\nRelating these fundamental parameters to Hadronic Parity Violation in nuclei\nhowever remains an outstanding theoretical challenge. One of the most\ninteresting observables in this respect is the parity violating hadronic\nneutral current: it is hard to measure in collider experiments and is thus the\nleast constrained observable of the Standard Model. Precision measurements of\nparity violating transitions in nuclei can help to improve these constraints.\nIn these systems however, the weak interaction is masked by effects of the\nseven orders of magnitude stronger non-perturbative strong interaction.\nTherefore, in order to relate experimental measurements of the parity violating\npion-nucleon couplings to the fundamental Lagrangian of the SM, these\nnon-perturbative effects have to be well understood. In this paper, we are\ngoing to present a Lattice QCD approach for computing the $\\Delta I{=}2$ parity\nviolating matrix element in proton proton scattering. This process does not\ninvolve disconnected diagrams in the isospin symmetric limit and is thus a\nperfect testbed for studying the feasibility of the more involved calculation\nof the parity violating pion-nucleon coupling.",
        "positive": "Higgs boson mass bounds in the presence of a heavy fourth quark family: We present Higgs boson mass bounds in a lattice regularization allowing thus\nfor non-perturbative investigations. In particular, we employ a lattice\nmodified chiral invariant Higgs-Yukawa model using the overlap operator. We\nshow results for the upper and lower Higgs boson mass bounds in the presence of\na heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We\nperform infinite volume extrapolations in most cases, and examine several\nvalues of the lattice cutoff. Furthermore, we argue that the lower Higgs boson\nmass bound is stable with respect to the addition of higher dimensional\noperators to the scalar field potential. Our results have severe consequences\nfor the phenomenology of a fourth generation of quarks if a light Higgs boson\nis discovered at the LHC."
    },
    {
        "anchor": "Comment on \"Relation between scattering amplitude and Bethe-Salpeter\n  wave function in quantum field theory\": We invalidate the arguments given in [T.Yamazaki and Y.Kuramashi, Phys. Rev.\nD96, 114511 (2017)] over the HAL QCD method for hadron-hadron interactions on\nthe lattice. We also pose questions on the practical usefulness of the method\nproposed in this reference.",
        "positive": "Statistical Angles on the Lattice QCD Signal-to-Noise Problem: The theory of quantum chromodynamics (QCD) encodes the strong interactions\nthat bind quarks and gluons into nucleons and that bind nucleons into nuclei.\nPredictive control of QCD would allow nuclear structure and reactions as well\nas properties of supernovae and neutron stars to be theoretically studied from\nfirst principles. Lattice QCD can represent generic QCD predictions in terms of\nwell-defined path integrals, but the sign and signal-to-noise problems have\nobstructed lattice QCD calculations of large nuclei and nuclear matter in\npractice. This thesis presents a statistical study of lattice QCD correlation\nfunctions, with a particular focus on characterizing the structure of the noise\nassociated with quantum fluctuations. The signal-to-noise problem in baryon\ncorrelation functions is demonstrated to arise from a sign problem associated\nwith Monte Carlo sampling of complex correlation functions. The phases of\ncomplex correlation functions are analyzed in the framework of circular\nstatistics, and the time evolution of the phase is shown to resemble a\nheavy-tailed random walk on the unit circle. Building on these observations, a\nnew technique called phase reweighting is investigated that involves\ncalculations of phase differences over fixed-length time intervals. Phase\nreweighting allows results for hadronic observables to be extracted from\nlarge-time correlation functions with constant signal-to-noise ratios. The\nsignal-to-noise problem re-emerges as the length of the phase-difference\ninterval is increased. Applications of phase reweighting to meson, baryon, and\ntwo-baryon systems are discussed."
    },
    {
        "anchor": "Including Tetraquark Operators in the Low-Lying Scalar Meson Sectors in\n  Lattice QCD: Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume\nusing a basis of single- and multi-hadron interpolating operators. Here we\nexamine the effect of including tetraquark operators on the spectrum in the\nscalar meson sectors containing the $K_0^*(700)$ ($\\kappa$) and the $a_0(980)$\nin $N_f = 2 + 1$ QCD, with $m_\\pi \\approx 230$ MeV. Preliminary results of\nadditional finite-volume states found using tetraquark operators are shown, and\npossible implications of these states are discussed.",
        "positive": "Lattice Charge Overlap: Towards the Elastic Limit: A numerical investigation of time-separated charge overlap measurements is\ncarried out for the pion in the context of lattice QCD using smeared Wilson\nfermions. The evolution of the charge distribution function is examined and the\nexpected asymptotic time behavior $\\sim e^{-(E_{q}-m_{\\pi})t}$, where $t$\nrepresents the charge density relative time separation, is clearly visible in\nthe Fourier transform. Values of the pion form factor are extracted using\npoint-to-smeared correlation functions and are seen to be consistent with the\nexpected monopole form from vector dominance. The implications of these results\nfor hadron structure calculations is briefly discussed."
    },
    {
        "anchor": "Four-Loop Perturbative Expansion for the Lattice $N$-Vector Model: We compute the four-loop contributions to the $\\beta$-function and the\nanomalous dimension of the field for the $O(N)$-invariant $N$-vector model.\nThese results are used to compute the second analytic corrections to the\ncorrelation length and the general spin-$n$ susceptibility.",
        "positive": "Blockspin Scheme and Cluster Algorithm for Quantum Spin Systems: We present a numerical study using a cluster algorithm for the 1-d $S=1/2$\nquantum Heisenberg models. The dynamical critical exponent for\nanti-ferromagnetic chains is $z=0.0(1)$ such that critical slowing down is\neliminated."
    },
    {
        "anchor": "Gauge Field Generation on Large-Scale GPU-Enabled Systems: Over the past years GPUs have been successfully applied to the task of\ninverting the fermion matrix in lattice QCD calculations. Even strong scaling\nto capability-level supercomputers, corresponding to O(100) GPUs or more has\nbeen achieved. However strong scaling a whole gauge field generation algorithm\nto this regim requires significantly more functionality than just having the\nmatrix inverter utilizing the GPUs and has not yet been accomplished. This\ncontribution extends QDP-JIT, the migration of SciDAC QDP++ to GPU-enabled\nparallel systems, to help to strong scale the whole Hybrid Monte-Carlo to this\nregime. Initial results are shown for gauge field generation with Chroma\nsimulating pure Wilson fermions on OLCF TitanDev.",
        "positive": "Mixed action simulations: approaching physical quark masses: Some algorithmic details of our $N_f=2+1$ QCD mixed action simulations with\noverlap valence and improved Wilson sea quarks are presented."
    },
    {
        "anchor": "The Electroweak Phase Transition in a Magnetic Field: We study the finite temperature electroweak phase transition in an external\nhypercharge U(1) magnetic field H_Y, using lattice Monte Carlo simulations. For\nsufficiently small fields, H_Y/T^2 < 0.3, the magnetic field makes the first\norder transition stronger, but it still turns into a crossover for Higgs masses\nm_H ~ 80 GeV. For larger fields, we observe a mixed phase analogous to a type I\nsuperconductor, where a single macroscopic tube of the symmetric phase,\nparallel to H_Y, penetrates through the broken phase. For the magnetic fields\nand Higgs masses studied, we did not see indications of the expected\nAmbjorn-Olesen phase, which should be similar to a type II superconductor.",
        "positive": "$D$ meson Semileptonic Decay Form Factors at $q^2 = 0$: We discuss preliminary results for the vector form factors $f_+^{\\{\\pi,K\\}}$\nat zero-momentum transfer for the decays $D\\to\\pi\\ell\\nu$ and $D\\to K \\ell\\nu$\nusing MILC's $N_f = 2+1+1$ HISQ ensembles at four lattice spacings, $a \\approx\n0.042, 0.06, 0.09$, and 0.12 fm, and various HISQ quark masses down to the\n(degenerate) physical light quark mass. We use the kinematic constraint\n$f_+(q^2)= f_0(q^2)$ at $q^2 = 0$ to determine the vector form factor from our\nstudy of the scalar current, which yields $f_0(0)$. Results are extrapolated to\nthe continuum physical point in the framework of hard pion/kaon SU(3)\nheavy-meson-staggered $\\chi$PT and Symanzik effective theory. Our calculation\nimproves upon the precision achieved in existing lattice-QCD calculations of\nthe vector form factors at $q^2=0$. We show the values of the CKM matrix\nelements $|V_{cs}|$ and $|V_{cd}|$ that we would obtain using our preliminary\nresults for the form factors together with recent experimental results, and\ndiscuss the implications of these values for the second row CKM unitarity."
    },
    {
        "anchor": "Does confinement imply CP invariance of the strong interactions?: The strong coupling constant $1/g^2$ and the vacuum angle $\\theta$ of the\nSU(3) Yang-Mills theory are investigated in the infrared limit under the\nrenormalization group flow. It is shown that the theory has an infrared\nattractive fixed point at $1/g^2 = \\theta = \\,0$, which leads to linear\nconfinement and naturally solves the strong CP problem. In particular, any\ninitial value of $\\theta \\neq 0$ is found to be driven to $\\theta = 0$ at\nmacroscopic distances, where quarks and gluons freeze into hadrons by the\nconfinement mechanism.",
        "positive": "Generation of electric current by magnetic field at the boundary:\n  quantum scale anomaly vs. semiclassical Meissner current outside of the\n  conformal limit: The scale (conformal) anomaly can generate an electric current near the\nboundary of a system in the presence of a static magnetic field. The magnitude\nof this magnetization current, produced at zero temperature and in the absence\nof matter, is proportional to a beta function associated with the\nrenormalization of the electric charge. Using first-principle lattice\nsimulations, we investigate how the breaking of the scale symmetry affects this\n``scale magnetic effect'' near a Dirichlet boundary in scalar QED (Abelian\nHiggs model). We demonstrate the interplay of the generated current with vortex\nexcitations both in symmetric (normal) and broken (superconducting) phases and\ncompare the results with the anomalous current produced in the conformal,\nscale-invariant regime. Possible experimental signatures of the effect in Dirac\nsemimetals are discussed."
    },
    {
        "anchor": "Weak Decays of Heavy-Light Mesons on the Lattice: Semi-Leptonic\n  Formfactors: We report results (on an intermediate statistics sample) of a study of weak\nsemi-leptonic formfactors of $B$ and $D$ decays, addressing the uncertainties\nfrom mass extrapolations to chiral and to heavy quarks. Moreover, we present a\nnonperturbative test to the LMK current renormalization scheme for vector\ncurrent {\\it transition} matrix elements and find remarkable agreement.",
        "positive": "Study of color superconductivity with Ginzburg-Landau effective action\n  on the lattice: We study thermal phase transitions of color superconductivity by the lattice\nsimulations of the Ginzburg-Landau (GL) effective theory. The theory is\nequivalent to the SU_ f(3) cross SU_c(3) Higgs model coupled to SU_c(3) color\ngauge fields. From the eigenvalues of a 3-by-3 gauge-invariant diquark\ncomposite, a clear distinction between the 2-flavor color superconductivity\n(2SC) and the color flavor locking (CFL) phase is made in a gauge invariant\nmanner. The thermal transitions between the normal phase and the\nsuperconducting phases are found to be first-order due to thermal gluons. The\nphase structure in the coupling-constant space is numerically explored and\nthree patterns of phase transition, i.e., normal to 2SC, normal to CFL and\nnormal to CFL via 2SC, are found in the chiral limit. These results agree\nqualitatively with the weak-coupling analysis of the GL theory."
    },
    {
        "anchor": "Results and Frontiers in Lattice Baryon Spectroscopy: The Lattice Hadron Physics Collaboration (LHPC) baryon spectroscopy effort is\nreviewed. To date the LHPC has performed exploratory Lattice QCD calculations\nof the low-lying spectrum of Nucleon and Delta baryons. These calculations\ndemonstrate the effectiveness of our method by obtaining the masses of an\nunprecedented number of excited states with definite quantum numbers. Future\nwork of the project is outlined.",
        "positive": "Species Doublers as Super Multiplets in Lattice Supersymmetry: Exact\n  Supersymmetry with Interactions for D=1 N=2: We propose a new lattice superfield formalism in momentum representation\nwhich accommodates species doublers of the lattice fermions and their bosonic\ncounterparts as super multiplets. We explicitly show that one dimensional N=2\nmodel with interactions has exact Lie algebraic supersymmetry on the lattice\nfor all super charges. In coordinate representation the finite difference\noperator is made to satisfy Leibnitz rule by introducing a non local product,\nthe ``star'' product, and the exact lattice supersymmetry is realized. The\nstandard momentum conservation is replaced on the lattice by the conservation\nof the sine of the momentum, which plays a crucial role in the formulation.\nHalf lattice spacing structure is essential for the one dimensional model and\nthe lattice supersymmetry transformation can be identified as a half lattice\nspacing translation combined with alternating sign structure. Invariance under\nfinite translations and locality in the continuum limit are explicitly\ninvestigated and shown to be recovered. Supersymmetric Ward identities are\nshown to be satisfied at one loop level. Lie algebraic lattice supersymmetry\nalgebra of this model suggests a close connection with Hopf algebraic exactness\nof the link approach formulation of lattice supersymmetry."
    },
    {
        "anchor": "Questionable Arguments for the Correctness of Perturbation Theory in\n  Non-Abelian Models: We analyze the arguments put forward recently by Niedermayer et al in favor\nof the correctness of conventional perturbation theory in non-Abelian models\nand supposedly showing that our super-instanton counterexample was sick. We\npoint out that within their own set of assumptions, the proof of Niedermayer et\nal regarding the correctness of perturbation theory is incorrect and provide a\ncorrect proof under more restrictive assumptions. We reply also to their claim\nthat the S-matrix bootstrap approach of Balog et al supports the existence of\nasymptotic freedom in the O(3) model.",
        "positive": "Colour confinement and dual superconductivity of the vacuum - II: The dual superconductivity of the vacuum in SU(3) gauge theory is\ninvestigated by constructing a disorder parameter which signals monopole\ncondensation in various abelian projections and by studying numerically on the\nlattice its behaviour at finite temperature. We find that the vacuum is a dual\nsuperconductor with respect to each U(1) of the residual gauge group after\nabelian projection independently of the abelian projection chosen. Like in the\nSU(2) case (discussed in a companion paper) a finite size scaling analysis\nenables us to extract the indices of the phase transition and our analysis is\nconsistent with independent determinations."
    },
    {
        "anchor": "Many avatars of the Wilson fermion: A perturbative analysis: We explore different branches of the fermion doublers with Wilson fermion in\nperturbation theory, in the context of additive mass renormalization and chiral\nanomaly, and show that by appropriately averaging over suitably chosen branches\none can reduce cut-off artifacts. Comparing the central branch with all other\nbranches, we find that the central branch, among all the avatars of the Wilson\nfermion, is the most suitable candidate for exploring near conformal lattice\nfield theories.",
        "positive": "Low temperature expansion for the 3-d Ising Model: We compute the weak coupling expansion for the energy of the three\ndimensional Ising model through 48 excited bonds. We also compute the\nmagnetization through 40 excited bonds. This was achieved via a recursive\nenumeration of states of fixed energy on a set of finite lattices. We use a\nlinear combination of lattices with a generalization of helical boundary\nconditions to eliminate finite volume effects."
    },
    {
        "anchor": "Non-perturbative renormalization of quark bilinear operators and B_K\n  using domain wall fermions: We present a calculation of the renormalization coefficients of the quark\nbilinear operators and the K-Kbar mixing parameter B_K. The coefficients\nrelating the bare lattice operators to those in the RI/MOM scheme are computed\nnon-perturbatively and then matched perturbatively to the MSbar scheme. The\ncoefficients are calculated on the RBC/UKQCD 2+1 flavor dynamical lattice\nconfigurations. Specifically we use a 16^3 x 32 lattice volume, the Iwasaki\ngauge action at beta=2.13 and domain wall fermions with L_s=16.",
        "positive": "Nucleon Excited State Wave Functions from Lattice QCD: We apply the eigenvectors from a variational analysis to successfully extract\nthe wave functions of even-parity excited states of the nucleon, including the\nRoper. We explore the first four states in the spectrum excited by the standard\nnucleon interpolating field. We find that the states exhibit a structure\nqualitatively consistent with a constituent quark model, where the ground,\nfirst-, second- and third-excited states have 0, 1, 2, and 3 nodes in the\nradial wave function of the d-quark about two $u$ quarks at the origin.\nMoreover the radial amplitude of the probability distribution is similar to\nthat predicted by constituent quark models. We present a detailed examination\nof the quark-mass dependence of the probability distributions for these states,\nsearching for a nontrivial role for the multi-particle components mixed in the\nfinite-volume QCD eigenstates. Finally we examine the dependence of the d-quark\nprobability distribution on the positions of the two u quarks. The results are\nfascinating, with the underlying S-wave orbitals governing the distributions\neven at rather large u-quark separations."
    },
    {
        "anchor": "Effects of Quenching and Partial Quenching on QCD Penguin Matrix\n  Elements: We point out that chiral transformation properties of penguin operators\nchange in the transition from unquenched to (partially) quenched QCD. The way\nin which this affects the lattice determination of weak matrix elements can be\nunderstood in the framework of (partially) quenched chiral perturbation theory.",
        "positive": "The calculations of Nucleon Electric Dipole Moment using background\n  field on Lattice QCD: Measurements of nucleon and nuclei Electric Dipole Moments (EDMs) play an\nimportant role in probing CP violation and exploring physics beyond the\nStandard Model. We extract the neutron EDM by measuring the energy shift of the\nnucleon two-point correlation function in the presence of a background field.\nThe UV divergence of the topological charge density operator is mitigated using\ngradient flow, and the diffusion effect induced by the gradient flow process is\nincluded into the fit ansatz. Our calculations were carried out on two 2+1 DWF\nfermion, Iwasaki, gauge field ensembles generated by the RBC/UKQCD\ncollaborations with inverse lattice spacing 1.73 GeV and pion masses of about\n340 and 420 MeV."
    },
    {
        "anchor": "QCD with two light dynamical chirally improved quarks: Mesons: We present results for the spectrum of light and strange mesons on\nconfigurations with two flavors of mass-degenerate Chirally Improved sea\nquarks. The calculations are performed on seven ensembles of lattice size\n16^3x32 at three different gauge couplings and with pion masses ranging from\n250 to 600 MeV. To reliably extract excited states, we use the variational\nmethod with an interpolator basis containing both gaussian and derivative quark\nsources. Both conventional and exotic channels up to spin 2 are considered.\nStrange quarks are treated within the partially quenched approximation. For\nkaons we investigate the mixing of interpolating fields corresponding to\ndefinite C-parity in the SU(3) limit. This enlarged basis allows for an\nimproved determination of the low-lying kaon spectrum. In addition to masses we\nalso extract the ratio of the pseudoscalar decay constants of the kaon and pion\nand obtain F_K/F_\\pi=1.215(41). The results presented here include some\nensembles from previous publications and the corresponding results supersede\nthe previously published values.",
        "positive": "Hamilton-Jacobi Equation and the Tree Formula for Proper Vertices: The tree formula, which relates proper and connected vertices, is shown to be\nthe solution to a Hamilton-Jacobi equation."
    },
    {
        "anchor": "Critical Exponents of the Classical Heisenberg Ferromagnet: In a recent letter, R.G. Brown and M. Ciftan (Phys. Rev. Lett. 76, 1352,\n1996) reported high precision Monte Carlo (MC) estimates of the static critical\nexponents of the classical 3D Heisenberg model, which stand in sharp contrast\nto values obtained by four independent approaches, namely by other recent high\nstatistics MC simulations, high-temperature series analyses, field theoretical\nmethods, and experimental studies. In reply to the above cited work we\nsubmitted this paper as a comment to Phys. Rev. Lett.",
        "positive": "Lattice study of the Kink soliton and the zero-mode problem for phi4 in\n  two dimensions: We study the $\\lambda\\phi^4_{1+1}$ kink solion and the zero-mode contribution\nto the Kink soliton mass in regions beyond the semiclassical regime. The\ncalculations are done in the non-trivial scaling region and where appropriate\nthe results are compared with the continuum, semiclassical values. We show, as\na function of parameter space, where the zero-mode contributions become\nsignificant."
    },
    {
        "anchor": "Witten-Veneziano Relation, Quenched QCD, and Overlap Fermions: The quarks in quenched QCD have an anomalous self-interaction in the flavor\nsinglet Goldstone boson channel. This coupling is extracted from a graph with\ndisconnected quark lines, and is used to infer the mass of the eta-prime meson\nin full QCD. When the fermions are described by an overlap action, the\nWitten-Veneziano relation is an exact relation between the topological\nsusceptibility (as defined through fermionic zero modes) and the inferred value\nof the eta-prime mass. Using an overlap action we compute the hairpin amplitude\nand determine the fermion zero-mode susceptibility, the inferred eta-prime mass\nand other parameters characterizing the low energy chiral properties of\nquenched QCD.",
        "positive": "Leptonic and semi-leptonic B decays: We present results for the semi-leptonic and leptonic decays of B mesons.\nThese non-perturbative matrix elements are important for constraining the CKM\nmatrix. Results are presented for the pseudoscalar and vector decay constants,\nas well as flavour breaking ratios and heavy quark symmetry relations. We\nconsider the chiral and momentum dependence of the semi-leptonic form factors\nof the decay B-> pi l nu and the soft pion relation (SPR) on the lattice. These\ncalculations were performed in the quenched approximation at two values of the\ncoupling with non-perturbatively order a improved action and currents."
    },
    {
        "anchor": "On the $B^{*'}\\to B$ transition: We present a first $N_{\\rm f}=2$ lattice estimate of the hadronic coupling\n$g_{12}$ which parametrizes the strong decay of a radially excited $B^*$ meson\ninto the ground state $B$ meson at zero recoil. We work in the static limit of\nHeavy Quark Effective Theory (HQET) and solve a Generalised Eigenvalue Problem\n(GEVP), which is necessary for the extraction of excited state properties.\nAfter an extrapolation to the continuum limit and a check of the pion mass\ndependence, we obtain $g_{12} = -0.17(4)$.",
        "positive": "Phase diagram of the three dimensional Thirring model - A Monte Carlo\n  study: Certain approximate solutions of the continuum Schwinger-Dyson Equations\n(SDEs) predict chiral symmetry breaking in the 3d Thirring model when the\nnumber of fermion flavors N_f<4.32 whereas others predict symmetry breaking for\nall N_f. Our results from Monte Carlo simulations with N_f=6, predict a second\norder chiral phase transition. The critical coupling in this case corresponds\nto an ultra-violet fixed point of the renormalization group defining a\nnon-trivial continuum limit. Further, our numerical simulations provide an\nestimate for the critical number of fermion flavors, N_fc \\approx 6.5."
    },
    {
        "anchor": "Positive representations of complex distributions on groups: A normalizable complex distribution $P(x)$ on a manifold $\\mathcal{M}$ can be\nregarded as a complex weight, thereby allowing to define expectation values of\nobservables $A(x)$ defined on $\\mathcal{M}$. Straightforward importance\nsampling, $x\\sim P$, is not available for non positive $P$, leading to the\nwell-known sign (or phase) problem. A positive representation $\\rho(z)$ of\n$P(x)$ is any normalizable positive distribution on the complexified manifold\n$\\mathcal{M}^c$, such that, $\\langle A(x)\\rangle_P = \\langle A(z) \\rangle_\\rho$\nfor a dense set of observables, where $A(z)$ stands for the analytically\ncontinued function on $\\mathcal{M}^c$. Such representations allow to carry out\nMonte Carlo calculations to obtain estimates of $\\langle A(x) \\rangle_P$,\nthrough the sampling $z \\sim \\rho$. In the present work we tackle the problem\nof constructing positive representations for complex weights defined on\nmanifolds of compact Lie groups, both Abelian and non Abelian, as required in\nlattice gauge field theories. Since the variance of the estimates increase for\nbroad representations, special attention is put on the question of localization\nof the support of the representations.",
        "positive": "Species doubling and effective Lagrangians: Coupling gauge fields to the chiral currents from an effective Lagrangian for\npseudoscalar mesons naturally gives rise to a species doubling phenomenon\nsimilar to that seen with fermionic fields in lattice gauge theory."
    },
    {
        "anchor": "A Non-Perturbative Analysis of the Finite T Phase Transition in\n  SU(2)xU(1) Electroweak Theory: The continuum 3d SU(2)$\\times$U(1)+Higgs theory is an effective theory for a\nlarge class of 4d high-temperature gauge theories, including the minimal\nstandard model and some of its supersymmetric extensions. We study the effects\nof the U(1) subgroup using lattice Monte Carlo techniques. When $g'^2/g^2$ is\nincreased from the zero corresponding to pure SU(2)+Higgs theory, the phase\ntransition gets stronger. However, the increase in the strength is close to\nwhat is expected perturbatively, and the qualitative features of the phase\ndiagram remain the same as for $g'^2=0$. In particular, the first order\ntransition still disappears for $m_H>m_{H,c}$. We measure the photon mass and\nmixing angle, and find that the mass vanishes in both phases within the\nstatistical errors.",
        "positive": "Scattering phases for fermion-fermion scattering in the Gross-Neveu\n  model: We extract scattering phases for fermion-fermion scattering from Monte Carlo\nsimulations of the two-dimensional Gross-Neveu model. This is done by means of\nL\\\"uscher's method, which exploits the volume dependence of the energies of\ntwo-particle states. The results are compared with the analytical predictions."
    },
    {
        "anchor": "The density of states approach for the simulation of finite density\n  quantum field theories: Finite density quantum field theories have evaded first principle Monte-Carlo\nsimulations due to the notorious sign-problem. The partition function of such\ntheories appears as the Fourier transform of the generalised density-of-states,\nwhich is the probability distribution of the imaginary part of the action. With\nthe advent of Wang-Landau type simulation techniques and recent advances, the\ndensity-of-states can be calculated over many hundreds of orders of magnitude.\nCurrent research addresses the question whether the achieved precision is high\nenough to reliably extract the finite density partition function, which is\nexponentially suppressed with the volume. In my talk, I review the\nstate-of-play for the high precision calculations of the density-of-states as\nwell as the recent progress for obtaining reliable results from highly\noscillating integrals. I will review recent progress for the $Z_3$ quantum\nfield theory for which results can be obtained from the simulation of the dual\ntheory, which appears to free of a sign problem.",
        "positive": "A Consumer's Guide to Lattice QCD Results: I present an overview of recent lattice QCD results on hadron spectroscopy\nand matrix elements. Case studies include light quark spectroscopy, the\ndetermination of $\\alpha_s$ from heavy quark spectroscopy, the D-meson decay\nconstant, a calculation of the Isgur-Wise function, and some examples of the\n(lack of) effect of sea quarks on matrix elements. The review is intended for\nthe non-expert. Talk presented at the 1993 Slac Summer Institute"
    },
    {
        "anchor": "Three Dirac operators on two architectures with one piece of code and no\n  hassle: A simple minded approach to implement three discretizations of the Dirac\noperator (staggered, Wilson, Brillouin) on two architectures (KNL and core i7)\nis presented. The idea is to use a high-level compiler along with OpenMP\nparallelization and SIMD pragmas, but to stay away from cache-line optimization\nand/or assembly-tuning. The implementation is for N_v right-hand-sides, and\nthis extra index is used to fill the SIMD pipeline. On one KNL node single\nprecision performance figures for N_c=3, N_v=12 read 475 Gflop/s, 345 Gflop/s,\nand 790 Gflop/s for the three discretization schemes, respectively.",
        "positive": "Quenched Hadron Spectrum and Decay Constants on the lattice: In this talk we present the results obtained from a study of ${\\cal O}(2000)$\n(quenched) lattice configurations from the APE collaboration, at\n$6.0\\le\\beta\\le 6.4$, using both the Wilson and the SW-Clover fermion action.\nWe determine the light hadronic spectrum and the meson decay constants. For the\nlight-light systems we find an agreement with the experimental data of $\\sim\n5%$ for mesonic masses and $\\sim 10%-15%$ for baryonic masses and pseudoscalar\ndecay constants; a larger deviation is present for the vector decay constants.\nFor the heavy-light decay constants we find $f_{D_s}=237 \\pm 16 MeV, f_{D} =\n221 \\pm 17 MeV (f_{D_s}/f_D=1.07(4)), f_{B_s} = 205 \\pm 35 MeV, f_{B} = 180 \\pm\n32 MeV (f_{B_s}/f_B=1.14(8))$, in good agreement with previous estimates."
    },
    {
        "anchor": "Critical flavour number of the Thirring model in three dimensions: The Thirring model is a four fermion theory with vector interaction. We study\nit in three dimensions, where it is closely related to QED and other models\nused to describe properties of graphene. In addition it is a good toy model to\nstudy chiral symmetry breaking, since a phase with broken chiral symmetry is\npresent for the model with one fermion flavour. On the other hand, there is no\nsuch phase in the limit of infinitely many fermion flavours. Thus, a transition\nat some critical flavour number Nfc is expected, where the broken phase\nvanishes. The model was already studied with different methods, including\nSchwinger-Dyson, functional renormalization group and lattice approaches. Most\nstudies agree that there is indeed a phase transition from a chirally symmetric\nphase to a spontaneously broken phase for a small number of fermion flavours.\nBut there is no agreement on the critical flavour number and further details of\nthe critical behaviour. Values of Nfc found in the literature usually range\nbetween 2 and 7. All earlier lattice studies were performed with staggered\nfermions, where it is questionable if the continuum limit of the lattice model\nhas the same chiral symmetry as the continuum model. We present an approach for\nsimulations of the Thirring model with SLAC fermions. With this choice, we can\nbe sure to implement the full chiral symmetry of the continuum model. First\nresults from simulations are shown but do not allow a reliable estimate of Nfc\nso far.",
        "positive": "Rotational Symmetry and Regularization Dependence in the\n  $\u03a6^4_4$-Model: We study the one component $\\Phi^4$ model for four different lattice actions\nin the Gaussian limit and for the Ising model in the broken phase. Emphasis is\nput on the euclidean invariance properties of the boson propagator. A measure\nof the violation of rotational symmetry serves as a tool to compare the\nregularization dependence of the triviality bound."
    },
    {
        "anchor": "Renormalization of the $3D$ $SU(N)$ scalar energy-momentum tensor using\n  the Wilson flow: In the holographic approach to cosmology, cosmological observables are\ndescribed in terms of correlators of a three-dimensional boundary quantum field\ntheory. As a concrete model, we study the $3D$ massless $SU(N)$ scalar matrix\nfield theory with a $\\phi^4$ interaction. On the lattice, the energy-momentum\ntensor (EMT) in this theory can mix with the operator $\\phi^2$. We utilize the\nWilson Flow to renormalize the EMT on the lattice, and present numerical\nresults for the mixing coefficient for $N = 2$. Obtaining the renormalized EMT\nwill allow us to make predictions for the CMB power spectra in the regime where\nthe dual QFT is non-perturbative.",
        "positive": "Structure and representation theory of double group of four-dimensional\n  cubic group: We generalize the concept of cubic group into any dimension and derive their\nconjugate classifications and representation theorys. Double group and spinor\nrepresentation are defined. A detailed calculation is carried out on the\nstructures of four-dimensional cubic group $O_4$ and its double group, as well\nas all inequivalent single-valued representations and spinor representations of\n$O_4$ . All representations are derived adopting Clifford theory of\ndecomposition of induced representations."
    },
    {
        "anchor": "n-Boson Energies at Finite Volume and Three-Boson Interactions: We calculate the volume dependence of the ground-state energy of n identical\nbosons with short-range repulsive interactions in a periodic spatial volume of\nside L, up to and including terms of order 1/L^6. With this result, Lattice QCD\ncalculations of the ground-state energies of three or more pions will allow for\na systematic extraction of the three-pion interaction at this order in the\nvolume expansion.",
        "positive": "Light- and strange-quark mass dependence of the $\u03c1(770)$ meson\n  properties: From an analysis of recent ($I=J=1$)-$\\pi\\pi$-phase-shift and\npseudoscalar-meson decay-constant lattice data on two distinct chiral\ntrajectories, where either the sum of the up, down and strange quark masses, or\nthe mass of the strange quark is kept fixed, we extract the light and strange\nquark mass dependence of the rho meson parameters, and make predictions of\nthose on chiral trajectories which involve lighter masses than the physical\nstrange quark mass. We find that the mass of the rho meson can get as light as\n$700$ MeV for strange quark mass zero at physical pion masses. While the ratio\nof the couplings to the $\\pi\\pi$ and $K\\bar{K}$ channels is equal to $\\sqrt{2}$\nat the SU(3) symmetric chiral trajectory."
    },
    {
        "anchor": "On the continuum limit of gauge-fixed compact U(1) lattice gauge theory: We investigate the continuum limit of a compact formulation of the lattice\nU(1) gauge theory in 4 dimensions using a nonperturbative gauge-fixed\nregularization. We find clear evidence of a continuous phase transition in the\npure gauge theory for all values of the gauge coupling (with gauge symmetry\nrestored). When probed with quenched staggered fermions with U(1) charge, the\ntheory clearly has a chiral transition for large gauge couplings. We identify\nthe only possible region in the parameter space where a continuum limit with\nnonperturbative physics may appear.",
        "positive": "$\u03c1$ meson decay width from 2+1 flavor lattice QCD: We perform a lattice QCD study of the $\\rho$ meson decay from the $N_f=2+1$\nfull QCD configurations generated with a renormalization group improved gauge\naction and a non-perturbatively $O(a)$-improved Wilson fermion action. The\nresonance parameters, the effective $\\rho\\to\\pi\\pi$ coupling constant and the\nresonance mass, are estimated from the $P$-wave scattering phase shift for the\nisospin I=1 two-pion system. The finite size formulas are employed to calculate\nthe phase shift from the energy on the lattice. Our calculations are carried\nout at two quark masses, $m_\\pi=410\\,{\\rm MeV}$ ($m_\\pi/m_\\rho=0.46$) and\n$m_\\pi=300\\,{\\rm MeV}$ ($m_\\pi/m_\\rho=0.35$), on a $32^3\\times 64$\n($La=2.9\\,{\\rm fm}$) lattice at the lattice spacing $a=0.091\\,{\\rm fm}$. We\ncompare our results at these two quark masses with those given in the previous\nworks using $N_f=2$ full QCD configurations and the experiment."
    },
    {
        "anchor": "Inhomogeneities in the $2$-Flavor Chiral Gross-Neveu Model: We investigate the finite-temperature and -density chiral Gross-Neveu model\nwith an axial U$_A$(1) symmetry in $1+1$ dimensions on the lattice. In the\nlimit where the number of flavors $N_\\mathrm{f}$ tends to infinity the\ncontinuum model has been solved analytically and shows two phases: a symmetric\nhigh-temperature phase with a vanishing condensate and a low-temperature phase\nin which the complex condensate forms a chiral spiral which breaks translation\ninvariance. In the lattice simulations we employ chiral SLAC fermions with\nexact axial symmetry. Similarly to $N_\\mathrm{f}\\to\\infty$, we find for $8$\nflavors, where quantum and thermal fluctuations are suppressed, two distinct\nregimes in the $(T,\\mu)$ phase diagram, characterized by qualitatively\ndifferent behavior of the two-point functions of the condensate fields. More\nsurprisingly, at $N_\\mathrm{f}=2$, where fluctuations are no longer suppressed,\nthe model still behaves similarly to the $N_\\mathrm{f}\\to\\infty$ model and we\nconclude that the chiral spiral leaves its footprints even on systems with a\nsmall number of flavors. For example, at low temperature the two-point\nfunctions are still dominated by chiral spirals with pitches proportional to\nthe inverse chemical potential, although in contrast to large-$N_\\mathrm{f}$\ntheir amplitudes decrease with distance. We argue that these results should not\nbe interpreted as the spontaneous breaking of a continuous symmetry, which is\nforbidden in two dimensions. Finally, using Dyson-Schwinger equations we\ncalculate the decay of the U$_A$(1)-invariant fermion four-point function in\nsearch for a BKT phase at zero temperature.",
        "positive": "The leading hadronic vacuum polarization contribution to the muon\n  anomalous magnetic moment using $N_f=2+1$ O($a$) improved Wilson quarks: We present a lattice calculation of the leading hadronic contribution to the\nanomalous magnetic moment of the muon. This work is based on a subset of the\nCLS ensembles with $N_f = 2+1$ dynamical quarks and a quenched charm quark.\nNoise reduction techniques are used to improve significantly the statistical\nprecision of the dominant light quark contribution. The main source of\nsystematic error comes from finite size effects which are estimated using the\nformalism described in Ref. [7] and based on our knowledge of the timelike pion\nform factor. The strange and charm quark contributions are under control and an\nestimate of the quark-disconnected contribution is included. Isospin breaking\neffects will be studied in a future publication but are included in the\nsystematic error using an estimate based on published lattice results. Our\nfinal result, $a_\\mu^{\\rm hvp} = (720.0\\pm 12.4 \\pm 6.8)\\times 10^{-10}$, has a\nprecision of about 2%."
    },
    {
        "anchor": "Phase Structure of lattice SU(2)xU_S(1) three-dimensional Gauge Theory: We discuss a phase diagram for a relativistic SU(2) x U_{S}(1) lattice gauge\ntheory, with emphasis on the formation of a parity-invariant chiral condensate,\nin the case when the $U_{S}(1)$ field is infinitely coupled, and the SU(2)\nfield is moved away from infinite coupling by means of a strong-coupling\nexpansion. We provide analytical arguments on the existence of (and partially\nderive) a critical line in coupling space, separating the phase of broken SU(2)\nsymmetry from that where the symmetry is unbroken. We review uncoventional\n(Kosterlitz-Thouless type) superconducting properties of the model, upon\ncoupling it to external electromagnetic potentials. We discuss the r\\^ole of\ninstantons of the unbroken subgroup U(1) of SU(2), in eventually destroying\nsuperconductivity under certain circumstances. The model may have applications\nto the theory of high-temperature superconductivity. In particular, we argue\nthat in the regime of the couplings leading to the broken SU(2) phase, the\nmodel may provide an explanation on the appearance of a pseudo-gap phase, lying\nbetween the antiferromagnetic and the superconducting phases. In such a phase,\na fermion mass gap appears in the theory, but there is no phase coherence, due\nto the Kosterlitz-Thouless mode of symmetry breaking. The absence of\nsuperconductivity in this phase is attributed to non-perturbative effects\n(instantons) of the subgroup U(1) of SU(2).",
        "positive": "Excited meson spectroscopy with chirally improved fermions: We present excited meson masses from quenched calculations using chirally\nimproved (CI) quarks at pion masses down to 350 MeV. The salient features of\nour analysis are the use of a matrix of correlators from various source and\nsink operators and a basis which includes quark sources with different spatial\nwidths, thereby improving overlap with states exhibiting radial excitations."
    },
    {
        "anchor": "A numerical study of a confined $Q\\bar{Q}$ system in compact U(1)\n  lattice gauge theory in 4D: We present a numerical study about the confining regime of compact U(1)\nlattice gauge theory in 4D. To address the problem, we exploit the duality\nproperties of the theory. The main features of this method are presented, and\nits possible advantages and limits with respect to alternative techniques are\nbriefly discussed. In Monte Carlo simulations, we focus our attention onto the\ncase when a pair of static external charges is present. Some results are shown,\nconcerning different observables which are of interest in order to understand\nthe confinement mechanism, like the profile of the electric field induced by\nthe static charges, and the ratios between Polyakov loop correlation functions\nat different distances.",
        "positive": "Dynamical quantum phase transitions in a noisy lattice gauge theory: Lattice gauge theories (LGTs) form an intriguing class of theories highly\nrelevant to both high-energy particle physics and low-energy condensed matter\nphysics with the rapid development of engineered quantum devices providing new\ntools to study e.g. dynamics of such theories. The massive Schwinger model is\nknown to exhibit intricate properties of more complicated theories and has\nrecently been shown to undergo dynamical quantum phase transitions out of\nequilibrium. With current technology, noise is inevitable and potentially fatal\nfor a successful quantum simulation. This paper studies the dynamics subject to\nnoise of a $(1+1)$D U$(1)$ quantum link model following a quench of the sign of\nthe mass term. We find that not only is the system capable of handling noise at\nrates realistic in NISQ-era devices, promising the possiblity to study the\ntarget dynamics with current technology, but the effect of noise can be\nunderstood in terms of simple models. Specifically the gauge-breaking nature of\nbit-flip channels results in exponential dampening of state amplitudes, and\nthus observables, which does not affect the structures of interest. This is\nespecially important as it demonstrates that the gauge theory can be\nsuccessfully studied with devices that only exhibit approximate gauge\ninvariance."
    },
    {
        "anchor": "Localization and chiral properties near the ordering transition of an\n  Anderson-like toy model for QCD: The Dirac operator in finite temperature QCD is equivalent to the Hamiltonian\nof an unconventional Anderson model, with on-site noise provided by the\nfluctuations of the Polyakov lines. The main features of its spectrum and\neigenvectors, concerning the density of low modes and their localization\nproperties, are qualitatively reproduced by a toy-model random Hamiltonian,\nbased on an Ising-type spin model mimicking the dynamics of the Polyakov lines.\nHere we study the low modes of this toy model in the vicinity of the ordering\ntransition of the spin model, and show that at the critical point the spectral\ndensity at the origin has a singularity, and the localization properties of the\nlowest modes change. This provides further evidence of the close relation\nbetween deconfinement, chiral transition and localization of the low modes.",
        "positive": "Mesonic and baryonic correlation functions at fine lattice spacings: We report on our on-going project to compute mesonic and baryonic two- and\nthree-point correlation functions in simulations using Nf=2 flavours of O(a)\nimproved Wilson quarks and the Wilson plaquette action. We present performance\nfigures for the DD-HMC algorithm on commodity cluster hardware and discuss the\nissue of critical slowing down, which is particularly pronounced for the\ntopological charge. The effectiveness of stochastic noise sources and Jacobi\nsmearing are investigated. Our preliminary results obtained at three quark\nmasses on 96x48^3 at beta=5.5 imply that the lattice spacing is about 0.06 fm,\nwhile the smallest pion mass in the current runs is around 360 MeV, which\ncorresponds to m_pi*L=5.3."
    },
    {
        "anchor": "Chirally improved Dirac operators: Studying the sensitivity to\n  topological excitations for zero and finite temperature: We discuss the construction and properties of an approximate solution of the\nGinsparg-Wilson equation, the so-called chirally improved lattice Dirac\noperator. In particular we study the behavior of its eigenmodes in smooth\ninstanton backgrounds as well as for thermalized gauge configurations on both\nsides of the QCD phase transition. We compare with results from other Dirac\noperators including the overlap operator. The results support the picture of\nchiral symmetry breaking being closely related to instantons.",
        "positive": "Wilson loops at finite N in 2D: Some exact expressions for non-selfintersecting Wilson loops in Yang Mills\ntheory on the infinite plane are reviewed."
    },
    {
        "anchor": "Testing chiral effective theory with quenched lattice QCD: We investigate two-point correlation functions of left-handed currents\ncomputed in quenched lattice QCD with the Neuberger-Dirac operator. We consider\ntwo lattice spacings a~0.09,0.12 fm and two different lattice extents L~ 1.5,\n2.0 fm; quark masses span both the p- and the epsilon-regimes. We compare the\nresults with the predictions of quenched chiral perturbation theory, with the\npurpose of testing to what extent the effective theory reproduces quenched QCD\nat low energy. In the p-regime we test volume and quark mass dependence of the\npseudoscalar decay constant and mass; in the epsilon-regime, we investigate\nvolume and topology dependence of the correlators. While the leading order\nbehaviour predicted by the effective theory is very well reproduced by the\nlattice data in the range of parameters that we explored, our numerical data\nare not precise enough to test next-to-leading order effects.",
        "positive": "Deconfinement transition and string tensions in SU(4) Yang-Mills Theory: We present results from numerical lattice calculations of SU(4) Yang-Mills\ntheory. This work has two goals: to determine the order of the finite\ntemperature deconfinement transition on an $N_t = 6$ lattice and to study the\nstring tensions between static charges in the irreducible representations of\nSU(4). Motivated by Pisarski and Tytgat's argument that a second-order\nSU($\\infty$) deconfinement transition would explain some features of the SU(3)\nand QCD transitions, we confirm older results on a coarser, $N_t = 4$, lattice.\nWe see a clear two-phase coexistence signal, characteristic of a first-order\ntransition, at $8/g^2 = 10.79$ on a $6\\times 20^3$ lattice, on which we also\ncompute a latent heat of $\\Delta\\epsilon\\approx 0.6 \\epsilon_{SB}$. Computing\nPolyakov loop correlation functions we calculate the string tension at finite\ntemperature in the confined phase between fundamental charges, $\\sigma_1$,\nbetween diquark charges, $\\sigma_2$, and between adjoint charges $\\sigma_4$. We\nfind that $1 < \\sigma_2/\\sigma_1 < 2$, and our result for the adjoint string\ntension $\\sigma_4$ is consistent with string breaking."
    },
    {
        "anchor": "Critical mass in nonzero temperature QCD with staggered fermions: The behaviour of the chiral condensate in QCD is investigated by means of a\nstudy of the distribution of the zeros of the partition function in the complex\nquark mass plane. Simulations are performed at fixed temperature on three\ndifferent spatial volumes at $\\beta=5.04$ and at $\\beta=4.9$ and $\\beta=5.2$ on\na $4^4$ lattice. Evidence is found for a chirally related transition at\nnon-zero quark mass in the intermediate coupling region for $\\beta < 5.2 $ but\nsuperimposed upon a smooth behaviour for the condensate. The critical mass at\nwhich this transition is found is only weakly dependent on the spatial volume\nand decreas with decreasing temperature.",
        "positive": "Gradient flows without blow-up for Lefschetz thimbles: We propose new gradient flows that define Lefschetz thimbles and do not blow\nup in a finite flow time. We study analytic properties of these gradient flows,\nand confirm them by numerical tests in simple examples."
    },
    {
        "anchor": "Finite volume effects in $B_K$ with improved staggered fermions: We extend our recent unquenched ($N_f=2+1$ flavor) calculation of $B_K$ using\nimproved staggered fermions by including in the fits the finite volume shift\npredicted by one-loop staggered chiral perturbation theory. The net result is\nto lower the result in the continuum limit by 0.6%. This shift is slightly\nsmaller than our previous estimate of finite volume effects based on a direct\ncomparison between different volumes. To include the finite volume effects in a\nreasonable time, we found it necessary to calculate them using Graphics\nProcessing Units.",
        "positive": "Overlap hypercube fermions in QCD with light quarks: We report on simulation results with overlap hypercube fermions (overlap HF)\n- a type of exactly chiral lattice fermions - and their link to chiral\nperturbation theory. We first sketch the construction of the overlap HF and\ndiscuss its high level of locality. Next we show applications in the p-regime\nof QCD, where we evaluate m_{\\pi}, m_{\\rho}, the quark mass according to the\nPCAC relation, the renormalisation constant Z_A and the pion decay constant\nF_{\\pi} as functions of the bare quark mass. F_{\\pi} is then reconsidered at\neven smaller quark masses in the epsilon-regime, along with the scalar\ncondensate \\Sigma. In that context we also discuss results for the topological\ncharges and susceptibility."
    },
    {
        "anchor": "SU(N) Quantum Antiferromagnets and the Phase Structure of QED in the\n  Strong Coupling Limit: We examine the strong coupling limit of both compact and non compact QED on a\nlattice with staggered fermions. We show that every SU(N) antiferromagnet with\nspins in a particular fundamental representation of the SU(N) Lie Algebra and\nwith nearest neighbor couplings on a bipartite lattice is exactly equivalent to\nthe infinite coupling limit of lattice QED with the numbers of flavors of\nelectrons related to N and the dimension of spacetime D+1. We find that,for\nboth compact and noncompact QED,when N is odd the ground state of the strong\ncoupling limit breaks chiral symmetry in any dimensions and for any N and the\ncondensate is an isoscalar mass operator. When N is even,chiral symmetry is\nbroken if D is bigger or equal to 2 and N is small enough and the order\nparameter is an isovector mass operator. We also find the exact ground state of\nthe lattice Coulomb gas as well as a variety of related lattice statistical\nsystems with long ranged interactions.",
        "positive": "F_B from moving B mesons: We show results for the B meson decay constant calculated both for B mesons\nat rest and those with non-zero momentum and using both the temporal and\nspatial components of the axial vector current. It is an important check of\nlattice systematic errors that all these determinations of f_B should agree. We\nalso describe how well different smearings for the B meson work at non-zero\nmomentum - the optimal smearing has a narrow smearing for the b quark."
    },
    {
        "anchor": "Peeking into the $\u03b8$ vacuum: We propose a subvolume method to study the $\\theta$ dependence of the free\nenergy density of the four-dimensional SU($N$) Yang-Mills theory on the\nlattice. As an attempt, the method is first applied to SU(2) Yang-Mills theory\nat $T=1.2\\,T_c$ to understand the systematics of the method. We then proceed to\nthe calculation of the vacuum energy density and obtain the $\\theta$ dependence\nqualitatively different from the high temperature case. The numerical results\ncombined with the theoretical requirements provide the evidence for the\nspontaneous CP violation at $\\theta = \\pi$, which is in accordance with the\nlarge $N$ prediction and indicates that the similarity between 4d SU($N$) and\n2d CP$^{N-1}$ theories does not hold for $N$=2.",
        "positive": "Roper Properties on the Lattice: An Update: In this proceeding, we give an overview of the latest progress in lattice-QCD\ncalculations of the Roper resonance, and Roper-nucleon electromagnetic and\naxial transition form factors using dynamical gauge ensembles."
    },
    {
        "anchor": "Chiral critical behavior of 3D lattice fermionic models with quartic\n  interactions: We study the critical behavior of the three-dimensional (3D) Gross-Neveu (GN)\nmodel with $N_f$ Dirac fermionic flavors and quartic interactions, at the\nchiral ${\\mathbb Z}_2$ transition in the massless ${\\mathbb Z}_2$-symmetric\nlimit. For this purpose, we consider a lattice GN model with staggered\nKogut-Susskind fermions and a scalar field coupled to the scalar bilinear\nfermionic operator, which effectively realizes the attractive four-fermion\ninteraction. We perform Monte Carlo (MC) simulations for $N_f=4,8,12,16$. By\nmeans of finite-size scaling analyses of the numerical data, we obtain\nestimates of the critical exponents that are compared with the large-$N_f$\npredictions obtained using the continuum GN field theory. We observe a\nsubstantial agreement. This confirms that lattice GN models with staggered\nfermions provide a nonpertubative realization of the GN quantum field theory,\neven though the lattice interactions explicitly break the flavor ${\\rm\nU}(N_f)\\otimes {\\rm U}(N_f)$ symmetry of the GN field theory, which is only\nrecovered in the critical limit.",
        "positive": "The derivation of the dual superconductor theory from the Maximal Center\n  projected SU(3) - gluodynamics: We consider the Center projected SU(3) gluodynamics and rewrite it as a dual\nsuperconductor theory. The center monopole field plays the role of Higgs field\nin the dual superconductor theory.\n  The center monopole creation operator is constructed."
    },
    {
        "anchor": "Numerical study of the equation of state for two flavor QCD at non-zero\n  baryon density: We discuss the equation of state (EoS) for two flavor QCD at non-zero\ntemperature and density. Derivatives of $\\ln Z$ with respect to quark chemical\npotential $\\mu_q$ are calculated up to sixth order. From this Taylor series,\nthe pressure, quark number density and associated susceptibilities are\nestimated as functions of temperature and $\\mu_q$. It is found that the\nfluctuations in the quark number density increase in the vicinity of the phase\ntransition temperature and the susceptibilities start to develop a pronounced\npeak as $\\mu_q$ is increased. This suggests the presence of a critical endpoint\nin the $(\\mu_q, T)$ plane. Moreover, we comment on the hadron resonance gas\nmodel, which explains well our simulation results below $T_c$.",
        "positive": "Neutron Electric Dipole Moments from Beyond the Standard Model Physics: Neutron Electric Dipole Moment (nEDM), a generic feature of CP-violation, is\npredicted to be very small in the Standard Model, but can be much larger in\nmost extensions of the model. In this talk, I will discuss the classification\nof the CP violating operators up to dimension 6 that can give rise to nEDM, and\nthen describe the mixing and renormalization structure of the operators of\ndimension 5 and lower in both dimensional and cutoff regularizations in general\nterms. Finally I will describe how to connect the dimension 5 operators, in\nparticular, the Chromoelectric Dipole Moment of the quarks, between MSbar\nscheme and a Regularization Independent prescription in the chiral limit."
    },
    {
        "anchor": "Probing the Yang-Mills vacuum with adjoint zero-modes: For the non-perturbative analysis of the topological content of Yang-Mills\ntheories, it is essential to disentangle long-range structures from short-range\nfluctuations. Some time ago, one of us proposed to use the adjoint modes of the\nDirac operator for this purpose. In this talk we analyse an implementation of\nthis idea that associates two Weyl fermionic modes in the adjoint\nrepresentation to every gauge field configuration. The densities of these modes\nprovide a filtered image of the self-dual and anti self-dual parts of the gauge\naction density. We present successful tests on the performance of this proposal\non a set of initial gauge field configurations.",
        "positive": "Domain wall fermion and chiral gauge theories on the lattice with exact\n  gauge invariance: We discuss how to construct anomaly-free chiral gauge theories on the lattice\nwith exact gauge invariance in the framework of domain wall fermion. Chiral\ngauge coupling is realized by introducing a five-dimensional gauge field which\ninterpolates between two different four-dimensional gauge fields at boundaries.\nThe five-dimensional dependence is compensated by a local and gauge-invariant\ncounter term. The cohomology problem to obtain the counter term is formulated\nin 5+1 dimensional space, using the Chern-Simons current induced from the\nfive-dimensional Wilson fermion. We clarify the connection to the invariant\nconstruction based on the Ginsparg-Wilson relation using overlap Dirac\noperator. Formula for the measure and the effective action of Weyl fermions are\nobtained in terms of five-dimensional lattice quantities."
    },
    {
        "anchor": "Kramers equation algorithm for simulations of QCD with two flavors of\n  Wilson fermions and gauge group SU(2): We compare the Hybrid Monte Carlo (HMC) and the Kramers equation algorithms\nfor simulations of QCD with two flavors of dynamical Wilson fermions and gauge\ngroup $SU(2)$. The results for the performance of both algorithms are obtained\non $6^312$, $12^4$ and $16^4$ lattices at a pion to $\\rho$ meson mass ratio of\n$m_\\pi/m_\\rho \\approx 0.9$. We find that the Kramers equation algorithm gives\nan equally good performance as the HMC algorithm. We demonstrate that the\nclassical equations of motion used in these algorithms lack reversibility in\npractical simulations and behave like those of a chaotic dynamical system with\na Liapunov exponent $\\nu \\approx 0.75$.",
        "positive": "Vacuum Decay and Euclidean Lattice Monte Carlo: The decay rate of a metastable vacuum is usually calculated using a\nsemiclassical approximation to the Euclidean path integral. The extension to a\ncomplete Euclidean lattice Monte Carlo computation, however, is hampered by\nanalytic continuations that are ill-suited to numerical treatment, and the\nnonequilibrium nature of a metastable state. In this paper we develop a new\nmethodology to compute vacuum decay rates from Monte Carlo simulations of\nEuclidean lattice theories. To test the new method, we consider simple quantum\nmechanical systems systems with metastable vacua. This work can be extended to\nEuclidean field theories, which we discuss in the Conclusions."
    },
    {
        "anchor": "String tension at finite temperature Lattice QCD: The critical curve of string tension as a function of the temperature is\ncomputed in SU(3) Lattice QCD. We present the results for the string tension\nutilizing a pair of Polyakov loop and antiloop, with two different techniques.\nWe compare the colour averaged loop-antiloop which is gauge invariant but is\nonly adequate to study the string tension, and the colour singlet loop-antiloop\nusing the Landau gauge fixing which also enables to compute the coulomb part of\nthe free energy.",
        "positive": "\"The Ising model on spherical lattices: dimer versus Monte Carlo\n  approach\": We study, using dimer and Monte Carlo approaches, the critical properties and\nfinite size effects of the Ising model on honeycomb lattices folded on the\ntetrahedron. We show that the main critical exponents are not affected by the\npresence of conical singularities. The finite size scaling of the position of\nthe maxima of the specific heat does not match, however, with the scaling of\nthe correlation length, and the thermodynamic limit is attained faster on the\nspherical surface than in corresponding lattices on the torus."
    },
    {
        "anchor": "Symmetric Mass Generation in Lattice Gauge Theory: We construct a four dimensional lattice gauge theory in which fermions\nacquire mass without breaking symmetries as a result of gauge interactions. Our\nmodel consists of reduced staggered fermions transforming in the bifundamental\nrepresentation of a $SU(2)\\times SU(2)$ gauge symmetry. This fermion\nrepresentation ensures that single site bilinear mass terms vanish identically.\nA symmetric four fermion operator is however allowed and we show numerical\nresults that show that a condensate of this operator develops in the vacuum.",
        "positive": "Decay constants of B and D mesons from improved relativistic lattice QCD\n  with two flavours of sea quarks: We present a calculation of the B and D meson decay constants in lattice QCD\nwith two (Nf=2) flavours of light dynamical quarks, using an O(a)-improved\nWilson action for both light and heavy quarks and a renormalization-group\nimproved gauge action. Simulations are made at three values of lattice spacing\na=0.22, 0.16, 0.11 fm and four values of sea quark mass in the range m_PS/m_V\n\\~= 0.8-0.6. Our estimate for the continuum values of the decay constants are\nfBd = 208(10)(11) MeV, fBs = 250(10)(13)(^{+8}_{-0}) MeV, fDd = 225(14)(14)\nMeV, fDs = 267(13)(17)(^{+10}_{-0}) MeV for Nf=2 where the statistical and\nsystematic errors are separately listed, and the third error for fBs and fDs\nshow uncertainty of determination of strange quark mass. We also carry out a\nset of quenched simulations using the same action to make a direct examination\nof sea quark effects. Taking the ratio of results for Nf=2 and Nf=0, we obtain\nfb^{Nf=2}/fb^{Nf=0} = 1.11(6), fbs^{Nf=2}/fbs^{Nf=0} = 1.14(5),\nfd^{Nf=2}/\\fd^{Nf=0} = 1.03(6), fds^{Nf=2}/\\fds^{Nf=0} = 1.07(5). They show a\n10-15% increase in the Nf=2 results over those of Nf=0 for the B meson decay\nconstants, while evidence for such a trend is statistically less clear for the\nD meson decay constants."
    },
    {
        "anchor": "pMR: A high-performance communication library: On many parallel machines, the time LQCD applications spent in communication\nis a significant contribution to the total wall-clock time, especially in the\nstrong-scaling limit. We present a novel high-performance communication library\nthat can be used as a de facto drop-in replacement for MPI in existing\nsoftware. Its lightweight nature that avoids some of the unnecessary overhead\nintroduced by MPI allows us to improve the communication performance of\napplications without any algorithmic or complicated implementation changes. As\na first real-world benchmark, we make use of the pMR library in the coarse-grid\nsolve of the Regensburg implementation of the DD-$\\alpha$AMG algorithm. On\nrealistic lattices, we see an improvement of a factor 2x in pure communication\ntime and total execution time savings of up to 20%.",
        "positive": "Obstructions to dimensional reduction in hot QCD: I describe results on screening masses in hot gauge theories. Wilsonian\neffective long distance theories called dimensionally reduced (DR) theories\ndescribe very well the longest screening length in pure gauge theories. In the\npresence of fermions, meson-like screening lengths dominate the long-distance\nphysics for 3T_c/2 < T < 3 T_c, and thus obstruct perturbative DR.\nExtrapolation of our results indicates that a form of this obstruction may\nremain till temperatures of 10 T_c or higher, and therefore affect the entire\nrange of temperature expected to be reached even at the Large Hadron Collider."
    },
    {
        "anchor": "Calculation of the axial charge in the epsilon and epsilon' regimes of\n  HBChPT: The axial charge g_A is calculated in the epsilon regime of Heavy Baryon\nChiral Perturbation Theory to order epsilon^3. To perform this calculation, we\ndevelop a technique to compute baryon properties in the epsilon regime of\nChiral Perturbation Theory. This technique includes contributions from pion\nzero momentum modes and can be used at arbitrary order, diagram by diagram, in\nthe $\\epsilon$ regime to calculate any matrix element. Also, a calculation of\ng_A in the epsilon' regime to order epsilon'^3 is performed. A discussion of\nthe domain of applicability for both the epsilon and epsilon' regimes is also\nincluded.",
        "positive": "Testing reweighting method for truncated Overlap fermions: The lattice QCD simulation with the lattice chiral symmetry is very\nattractive, however, it is difficult to maintain the symmetry at a modest\nnumerical computation cost. A candidate to reduce the computational cost during\nthe configuration generation with the HMC algorithm is to relax the requirement\nof the chiral symmetry and to use the reweighing method recovering the symmetry\nat the measurement phase. In this talk, we presented the reweighing method to\nrestore the chiral symmetry of the truncated overlap fermion operator. In order\nto avoid the large discrepancy between the truncated overlap operator and the\nexact overlap operator, we split the reweighting factor into several steps\ngradually increasing the order of truncation. We investigated the truncation\ndependence of the reweighting factor on a set of quenched $8^3\\times 32$\nlattice configurations generated with the DBW2 gauge action. We found that a\nlarge fluctuation on the reweighting factor between a high-order truncated\noverlap operator and the exact overlap operator on a couple of configurations.\nThe origin of the large fluctuation seems to be due to a small eigenvalue of\nthe overlap kernel on these configurations."
    },
    {
        "anchor": "Inhomogeneity of rotating gluon plasma and Tolman-Ehrenfest law in\n  imaginary time: lattice results for fast imaginary rotation: We present the results of first-principle numerical simulations of Euclidean\nSU(3) Yang-Mills plasma rotating with a high imaginary angular frequency. The\nrigid Euclidean rotation is introduced via ``rotwisted'' boundary conditions\nalong imaginary time direction. The Polyakov loop in the co-rotating Euclidean\nreference frame shows the emergence of a spatially inhomogeneous\nconfining-deconfining phase through a broad crossover transition. A\ncontinuation of our numerical results to Minkowski spacetime suggests that the\ngluon plasma, rotating at real angular frequencies, produces a new\ninhomogeneous phase possessing the confining phase near the rotation axis and\nthe deconfinement phase in the outer regions. The inhomogeneous phase structure\nhas a purely kinematic origin, rooted in the Tolman-Ehrenfest effect in a\nrotating medium. We also derive the Euclidean version of the Tolman-Ehrenfest\nlaw in imaginary time formalism and discuss two definitions of temperature at\nimaginary Euclidean rotation.",
        "positive": "Unquenched complex Dirac spectra at nonzero chemical potential:\n  two-colour QCD lattice data versus matrix model: We compare analytic predictions of non-Hermitian chiral random matrix theory\nwith the complex Dirac operator eigenvalue spectrum of two-colour lattice gauge\ntheory with dynamical fermions at nonzero chemical potential. The Dirac\neigenvalues come in complex conjugate pairs, making the action of this theory\nreal, and positive for our choice of two staggered flavours. This enables us to\nuse standard Monte-Carlo in testing the influence of chemical potential and\nquark mass on complex eigenvalues close to the origin. We find an excellent\nagreement between the analytic predictions and our data for two different\nvolumes over a range of chemical potentials below the chiral phase transition.\nIn particular we detect the effect of unquenching when going to very small\nquark masses."
    },
    {
        "anchor": "Tempered Fermions in the Hybrid Monte Carlo Algorithm: Parallel tempering simulates at many quark masses simultaneously, by changing\nthe mass during the simulation while remaining in equilibrium. The algorithm is\nfaster than pure HMC if more than one mass is needed, and works better the\nsmaller the smallest mass is.",
        "positive": "First results from 2+1 dynamical quark flavors on an anisotropic\n  lattice: light-hadron spectroscopy and setting the strange-quark mass: We present the first light-hadron spectroscopy on a set of $N_f=2+1$\ndynamical, anisotropic lattices. A convenient set of coordinates that\nparameterize the two-dimensional plane of light and strange-quark masses is\nintroduced. These coordinates are used to extrapolate data obtained at the\nsimulated values of the quark masses to the physical light and strange-quark\npoint. A measurement of the Sommer scale on these ensembles is made, and the\nperformance of the hybrid Monte Carlo algorithm used for generating the\nensembles is estimated."
    },
    {
        "anchor": "Lattice simulation of 2+1 flavors of overlap light quarks: We report on the status of the dynamical overlap QCD simulation project by\nthe JLQCD collaboration. After completing two-flavor QCD simulation on a\n16^3x32 lattice at lattice spacing a 0.12 fm, we started a series of runs with\n2+1 flavors. In this report, we describe an outline of our algorithms,\nparameter choices, and some early physics results of this second phase of our\nproject.",
        "positive": "Lattice calculation of SU(3) flavor breaking ratios in B - anti-B mixing: We present an unquenched lattice calculation for the SU(3) flavor breaking\nratios of the heavy-light decay constants and the $\\Delta B = 2$ matrix\nelements. The calculation was performed on $16^3 \\times 32$ lattices with two\ndynamical flavors of domain-wall quarks and inverse lattice spacing $1/a =\n1.69(5)$ GeV. Heavy quarks were implemented using an improved lattice\nformulation of the static approximation. In the infinite heavy-quark mass limit\nwe obtain $f_{B_s}/f_{B_d} = 1.29(4)(6)$, $B_{B_s}/B_{B_d} = 1.06(6)(4)$, $\\xi\n= 1.33(8)(8)$ where the first error is statistical and the second systematic."
    },
    {
        "anchor": "Window observable for the hadronic vacuum polarization contribution to\n  the muon $g-2$ from lattice QCD: Euclidean time windows in the integral representation of the hadronic vacuum\npolarization contribution to the muon $g-2$ serve to test the consistency of\nlattice calculations and may help in tracing the origins of a potential tension\nbetween lattice and data-driven evaluations. In this paper, we present results\nfor the intermediate time window observable computed using O($a$) improved\nWilson fermions at six values of the lattice spacings below 0.1\\,fm and pion\nmasses down to the physical value. Using two different sets of improvement\ncoefficients in the definitions of the local and conserved vector currents, we\nperform a detailed scaling study which results in a fully controlled\nextrapolation to the continuum limit without any additional treatment of the\ndata, except for the inclusion of finite-volume corrections. To determine the\nlatter, we use a combination of the method of Hansen and Patella and the\nMeyer-Lellouch-L\\\"uscher procedure employing the Gounaris-Sakurai\nparameterization for the pion form factor. We correct our results for\nisospin-breaking effects via the perturbative expansion of QCD+QED around the\nisosymmetric theory. Our result at the physical point is\n$a_\\mu^{\\mathrm{win}}=(237.30\\pm0.79_{\\rm stat}\\pm1.22_{\\rm\nsyst})\\times10^{-10}$, where the systematic error includes an estimate of the\nuncertainty due to the quenched charm quark in our calculation. Our result\ndisplays a tension of 3.9$\\sigma$ with a recent evaluation of\n$a_\\mu^{\\mathrm{win}}$ based on the data-driven method.",
        "positive": "Charge Fluctuations as Thermometer for Heavy-Ion Collisions: We present a determination of freeze-out conditions in heavy-ion collisions\nbased on ratios of cu- mulants of net electric charge fluctuations obtained\nfrom lattice QCD. These ratios can reliably be calculated for a wide range of\nchemical potential values by using a next-to-leading order Taylor series\nexpansion around the limit of vanishing baryon, electric charge and strangeness\nchemical potentials. We first determine the strangeness and electric charge\nchemical potentials that characterize the conditions in heavy ion collisions at\nRHIC and LHC. We then show that a comparison of lattice QCD results for ratios\nof up to third order cumulants of electric charge fluctuations with\nexperimental results allows us to extract the freeze-out baryon chemical\npotential and the freeze-out temperature. We apply our method to preliminary\ndata of the STAR and PHENIX collaborations."
    },
    {
        "anchor": "Resonance Scattering on the Lattice with Non-Zero Total Momentum: Most hadronic particles are resonances: for example, the rho meson appears as\na resonance in the elastic scattering of two pions. A method by Luescher\nenables one to measure the properties of the resonance particles from finite\nlattices. We present here a more general method which includes scattering\nprocesses where the total momentum of the particles is non-zero. The main\nadvantage is that the resonance scattering can be observed in a considerably\nsmaller spatial volume. We test the method with a simple 3+1 dimensional spin\nmodel, and find excellent agreement between the zero momentum and the non-zero\nmomentum scattering sectors.",
        "positive": "Infinite-range correlations in 1D systems with continuous symmetry: O(N)-symmetric lattice scalar fields are considered, coupled to a chemical\npotential and source terms. At the example of N=2, it is shown that such\nsystems can even in (0+1) dimensions produce infinite-range correlations and a\nnon-zero vacuum expectation value whenever the chemical potential assumes\ncertain discrete values. Different mechanisms for how the latter phenomena are\nproduced are discussed, depending on whether source terms are set to zero or\nnon-zero values. In the conclusion, the relation of these findings to the\nMermin-Wagner theorem is addressed."
    },
    {
        "anchor": "Restoration of supersymmetry on the lattice: Two-dimensional\n  $\\mathcal{N}=(2,2)$ supersymmetric Yang-Mills theory: By numerically investigating the conservation law of the supercurrent, we\nconfirm the restoration of supersymmetry in Sugino's lattice formulation of the\ntwo-dimensional $\\mathcal{N}=(2,2)$ supersymmetric SU(2) Yang-Mills theory with\na scalar mass term. Subtlety in the case without the scalar mass term, that\nappears to ruin perturbative power counting, is also pointed out.",
        "positive": "Manifestation of Sea Quark Effects in the Strong Coupling Constant in\n  Lattice QCD: We demonstrate that sea quark effects of a magnitude expected from\nrenormalization group considerations are clearly visible in the strong coupling\nconstant measured in current full QCD simulations. Building on this result an\nestimate of $\\alpha_{\\overline{MS}}^{(5)}(M_Z)$ is made employing the\ncharmonium $1S-1P$ mass splitting calculated on full QCD configurations\ngenerated with two flavors of dynamical Kogut-Susskind quarks to fix the scale."
    },
    {
        "anchor": "Symanzik Improvement In The Static Quark Potential: A systematic investigation of Symanzic improvement in the gauge field action\nis performed for the static quark potential in quenched QCD. We consider\nSymanzik improved gauge field configurations on a 16^3 X 32 lattice with a\nrelatively coarse lattice spacing of 0.165(2)fm. A matched set of standard\nWilson gauge configurations is prepared at \\beta = 5.74 with the same physical\nvolume and lattice spacing and is studied for comparison. We find that, despite\nthe coarse lattice spacing, the unimproved and less-expensive Wilson action\ndoes as well as the Symanzik action in allowing us to extract the static quark\npotential at large qqbar separations. We have considered novel methods for\nstepping off-axis in the static quark potential which provides new insights\ninto the extent to which the ground state potential dominates the Wilson loop\ncorrelation function.",
        "positive": "Two-Color Schrodinger Functional with Six-Flavors of Stout-Smeared\n  Wilson Fermions: We study the Schr\\\"odinger functional running coupling in the SU(2) gauge\ntheory with six-flavors of massless fermions. The aim is to determine whether\nthe above theory has an infrared fixed point (IRFP). We use the standard Wilson\ngauge action and the stout-smeared Wilson fermion action. Here we present a\ndetermination of the critical mass as a function of the bare coupling and a\npreliminary study of the phase diagram of this lattice action. We also find\npreliminary indication that this theory has no IRFP. While this conclusion is\nnot yet definite, we also show that with this approach we will be able to take\na proper continuum limit and clearly determine the status of this theory with a\nreasonable amount of computer time."
    },
    {
        "anchor": "Tensor renormalization group study of the 2d O(3) model: We present our progress on a study of the $O(3)$ model in two-dimensions\nusing the Tensor Renormalization Group method. We first construct the theory in\nterms of tensors, and show how to construct $n$-point correlation functions. We\nthen give results for thermodynamic quantities at finite and infinite volume,\nas well as 2-point correlation function data. We discuss some of the advantages\nand challenges of tensor renormalization and future directions in which to\nwork.",
        "positive": "String Breaking and Monopoles: a Case Study in the 3D Abelian Higgs\n  Model: We study the breaking of the string spanned between test charges in the three\ndimensional Abelian Higgs model with compact gauge field and fundamentally\ncharged Higgs field at zero temperature. In agreement with current expectations\nwe demonstrate that string breaking is associated with pairing of monopoles.\nHowever, the string breaking is not accompanied by an ordinary phase\ntransition."
    },
    {
        "anchor": "Axial resonances a1(1260), b1(1235) and their decays from the lattice: The light axial-vector resonances $a_1(1260)$ and $b_1(1235)$ are explored in\nNf=2 lattice QCD by simulating the corresponding scattering channels $\\rho\\pi$\nand $\\omega\\pi$. Interpolating fields $\\bar{q} q$ and $\\rho\\pi$ or $\\omega\\pi$\nare used to extract the s-wave phase shifts for the first time. The $\\rho$ and\n$\\omega$ are treated as stable and we argue that this is justified in the\nconsidered energy range and for our parameters $m_\\pi\\simeq 266~$MeV and\n$L\\simeq 2~$fm. We neglect other channels that would be open when using\nphysical masses in continuum. Assuming a resonance interpretation a\nBreit-Wigner fit to the phase shift gives the $a_1(1260)$ resonance mass\n$m_{a1}^{res}=1.435(53)(^{+0}_{-109})$ GeV compared to $m_{a1}^{exp}=1.230(40)$\nGeV. The $a_1$ width $\\Gamma_{a1}(s)=g^2 p/s$ is parametrized in terms of the\ncoupling and we obtain $g_{a_1\\rho\\pi}=1.71(39)$ GeV compared to\n$g_{a_1\\rho\\pi}^{exp}=1.35(30)$ GeV derived from $\\Gamma_{a1}^{exp}=425(175)$\nMeV. In the $b_1$ channel, we find energy levels related to $\\pi(0)\\omega(0)$\nand $b_1(1235)$, and the lowest level is found at $E_1 \\gtrsim m_\\omega+m_\\pi$\nbut is within uncertainty also compatible with an attractive interaction.\nAssuming the coupling $g_{b_1\\omega\\pi}$ extracted from the experimental width\nwe estimate $m_{b_1}^{res}=1.414(36)(^{+0}_{-83})$.",
        "positive": "Light quark masses from the lattice: A completely non-perturbative estimate is given for the u/d and strange quark\nmasses in quenched QCD using O(a) improved fermions and, for comparison, Wilson\nfermions. For improved fermions we find m_{u/d}^MSbar(\\mu=2 GeV) = 4.4(2) MeV,\nm_s^MSbar(\\mu=2 GeV) = 105(4) MeV when using r_0 to set the physical scale."
    },
    {
        "anchor": "Perturbation theory for O(3) topological charge correlators: To check the consistency of positivity requirements for the two-point\ncorrelation function of the topological charge density, which were identified\nin a previous paper, we are computing perturbatively this two-point correlation\nfunction in the two-dimensional O(3) model. We find that at the one-loop level\nthese requirements are fulfilled.",
        "positive": "Pentaquarks: Status and Perspectives for Lattice Calculations: The present status of pentaquark spectroscopy in lattice QCD is reviewed.\nThis talk also includes a brief introduction of pentaquark baryons."
    },
    {
        "anchor": "Baryon Spectroscopy on the Lattice: Recent lattice QCD calculations of the baryon spectrum are outlined.",
        "positive": "Towards a density of states approach for dense matter systems: The density-of-states method (Phys.Rev.Lett. 109 (2012) 111601) features an\nexponential error suppression and is not restricted to theories with positive\nprobabilistic weight. It is applied to the SU(2) gauge theory at finite\ndensities of heavy quarks. The key ingredient here is the Polyakov line\nprobability distribution, which is obtained of over 80 orders of magnitude. We\nbriefly address whether the exponential error suppression could be sufficient\nto simulate theories with a strong sign problem."
    },
    {
        "anchor": "Radiative transitions in charmonium from $N_f=2$ twisted mass lattice\n  QCD: We present a study for charmonium radiative transitions:\n$J/\\psi\\rightarrow\\eta_c\\gamma$, $\\chi_{c0}\\rightarrow J/\\Psi\\gamma$ and\n$h_c\\rightarrow\\eta_c\\gamma$ using $N_f=2$ twisted mass lattice QCD gauge\nconfigurations. The single-quark vector form factors for $\\eta_c$ and\n$\\chi_{c0}$ are also determined. The simulation is performed at a lattice\nspacing of $a= 0.06666$ fm and the lattice size is $32^3\\times 64$. After\nextrapolation of lattice data at nonzero $Q^2$ to 0, we compare our results\nwith previous quenched lattice results and the available experimental values.",
        "positive": "An Improved Single-Plaquette Gauge Action: We describe and test a nonperturbatively improved single-plaquette lattice\naction for 4-d SU(2) and SU(3) pure gauge theory, which suppresses large\nfluctuations of the plaquette, without requiring the naive continuum limit for\nsmooth fields. We tune the action parameters based on torelon masses in\nmoderate cubic physical volumes, and investigate the size of cut-off effects in\nother physical quantities, including torelon masses in asymmetric spatial\nvolumes, the static quark potential, and gradient flow observables. In 2-d O(N)\nmodels similarly constructed nearest-neighbor actions have led to a drastic\nreduction of cut-off effects, down to the permille level, in a wide variety of\nphysical quantities. In the gauge theories, we find significant reduction of\nlattice artifacts, and for some observables, the coarsest lattice result is\nvery close to the continuum value. We estimate an improvement factor of 40\ncompared to using the Wilson gauge action to achieve the same statistical\naccuracy and suppression of cut-off effects. The simplicity of the gauge action\nmakes it amenable for dynamical fermion simulations."
    },
    {
        "anchor": "Multigrid Solver on Fugaku: We report an implementation of a multigrid solver for the Clover fermion on\nsupercomputer Fugaku, which uses A64FX CPU with Arm architecture. On Fugaku, a\nhighly optimized implementation of BiCGStab solver with domain decomposed\npreconditioner for the Clover fermion, called QCD Wide SIMD library (QWS), is\navailable. We use the preconditioner in QWS as a smoother of the multigrid\nsolver. Our implementation shows reasonably good scaling and performance. The\ncode is developed by using Bridge++ code framework and its extension.",
        "positive": "The universality class of the electroweak theory: We study the universality class and critical properties of the electroweak\ntheory at finite temperature. Such critical behaviour is found near the\nendpoint m_H=m_{H,c} of the line of first order electroweak phase transitions\nin a wide class of theories, including the Standard Model (SM) and a part of\nthe parameter space of the Minimal Sypersymmetric Standard Model (MSSM). We\nfind that the location of the endpoint corresponds to the Higgs mass m_{H,c} =\n72(2) GeV in the SM with sin^2 theta_W = 0, and m_{H,c} < 80 GeV with sin^2\ntheta_W = 0.23. As experimentally m_H > 88 GeV, there is no electroweak phase\ntransition in the SM. We compute the corresponding critical indices and provide\nstrong evidence that the phase transitions near the endpoint fall into the\nthree dimensional Ising universality class."
    },
    {
        "anchor": "Cooling Stochastic Quantization with colored noise: Smoothing of field configurations is highly important for precision\ncalculations of physical quantities on the lattice. We present a cooling method\nbased on Stochastic Quantization with a built-in UV momentum cutoff. The latter\nis implemented via a UV-regularized, hence colored, noise term. Our method is\ntested in a two-dimensional scalar field theory. We show, that UV modes can be\nremoved systematically without altering the physics content of the theory. The\napproach has an interpretation in terms of the non-perturbative (Wilsonian)\nrenormalization group that facilitates the physics interpretation of the cutoff\nprocedure. It also can be used to define the maximal colored cooling applicable\nwithout changing the theory.",
        "positive": "The Light Hadron Spectrum and Decay Constants in Quenched Lattice QCD: We present results for light hadrons composed of both degenerate and\nnon-degenerate quarks in quenched lattice QCD. We calculate masses and decay\nconstants using 60 gauge configurations with an $O(a)$--improved fermion action\nat $\\beta = 6.2$. Using the $\\rho$ mass to set the scale, we find hadron masses\nwithin two to three standard deviations of the experimental values (given in\nparentheses): $m_{K^*}=868\\er{9}{8}$~MeV (892~MeV),\n$m_{\\phi}=970\\err{20}{10}$~MeV (1020~MeV), $m_N=820\\err{90}{60}$~MeV (938~MeV),\n$m_\\Delta=1300\\errr{100}{100}$~MeV (1232~MeV) and\n$m_\\Omega=1650\\err{70}{50}$~MeV (1672~MeV). Direct comparison with experiment\nfor decay constants is obscured by uncertainty in current renormalisations.\nHowever, for ratios of decay constants we obtain $f_K/f_\\pi=1.20\\er{3}{2}$\n(1.22) and $f_\\phi/f_\\rho=1.13\\er{2}{3}$ (1.22)."
    },
    {
        "anchor": "Roles of the quark field in the infrared lattice Coulomb gauge and\n  Landau gauge QCD: The effective coupling of QCD is measured by using the gauge configurations\nproduced by the MILC collaboration in which the Kogut Susskind (KS) fermion is\nincorporated and by using that produced by the QCDOC collaboration in which the\ndomain wall fermion (DWF) is incorporated. We fix the gauge to the Landau gauge\nand to the Coulomb gauge. The infrared effective coupling in the Coulomb gauge\nagrees with the recent extraction at JLab, but that in the Landau gauge shows\ninfrared suppression. The suppression is expected to be due to the color\nanti-symmetric ghost propagator which in the unquenched configurations has\nstronger infrared singularity than the color diagonal ghost propagator. The\nCoulomb form factor in the infrared depends on the kind of the fermion\nincorporated in the system and the temperature. The quark has the effect of\nquenching randomness and the fluctuation of the color anti-symmetric ghost\npropagator is reduced in the unquenched configuration, and the Kugo-Ojima\nparameter c is closer to 1 in the unquenched configuration than in the quenched\nconfiguration.",
        "positive": "BSM Kaon Mixing at the Physical Point: We present new preliminary results for bag parameters and ratios of the BSM\nkaon mixing operators measured at the physical point. The results are obtained\nfrom simulations of domain wall fermion QCD with 2+1 flavours with an Iwasaki\ngauge, and now include pion and kaon masses very close to the physical point.\nWe compare these results to our collaboration's previous results obtained from\nheavier simulated quarks."
    },
    {
        "anchor": "Continuum extrapolation of the critical endpoint in 4-flavor QCD with\n  Wilson-Clover fermions: We report our study on the critical endpoint of the finite temperature phase\ntransition in 4-flavor QCD with Wilson-Clover fermions. Using the kurtosis\nintersection method, we determined the critical endpoint on lattices with $N_t$\n= 4, 6 and 8. Our continuum extrapolated results show that the pseudo-scalar\nmeson mass at the critical endpoint, $m_\\mathrm{PS,E}$, for 4-flavor is clearly\nlarger than that for 3-flavor. We also compared our results to those with\nstaggered fermions and found that $m_\\mathrm{PS,E}/T_E$ for 4-flavor with\nWilson fermions might remain finite even in the continuum limit in contrast to\nthat with staggered fermions, where $m_\\mathrm{PS,E}/T_E$ is very close to\nzero, which suggests that the difference between Wilson and staggered fermions\nis at least not due to the rooting.",
        "positive": "Non-perturbative renormalization of overlap quark bilinears on\n  2+1-flavor domain wall fermion configurations: We present renormalization constants of overlap quark bilinear operators on\n2+1-flavor domain wall fermion configurations. This setup is being used by the\nchiQCD collaboration in calculations of physical quantities such as strangeness\nin the nucleon and the strange and charm quark masses. The scale independent\nrenormalization constant for the axial vector current is computed using the\nWard Identity. The renormalization constants for scalar, pseudoscalar and\nvector current are calculated in the RI-MOM scheme. Results in the MS-bar\nscheme are also given. The step scaling function of quark masses in the RI-MOM\nscheme is computed as well. The analysis uses, in total, six different\nensembles of three sea quarks each on two lattices with sizes 24^3x64 and\n32^3x64 at spacings a=(1.73 GeV)^{-1} and (2.28 GeV)^{-1}, respectively."
    },
    {
        "anchor": "SU(N_c) gauge theories at deconfinement: The deconfinement transition in SU($N_c$) Yang--Mills is investigated by\nMonte Carlo simulations of the gauge theory discretized on a spacetime lattice.\nWe present new results for $ 4 \\le N_c \\le 8$ (in particular, for $N_c = 5$ and\n$N_c = 7$), which are analysed together with previously published results. The\nincreased amount of data, the improved statistics and simulations closer to the\ncontinuum limit provide us with better control over systematic errors. After\nperforming the thermodynamic limit, numerical results for the ratio of the\ncritical temperature $T_c$ over the square root of the string tension\n$\\sqrt{\\sigma}$ obtained on lattices with temporal extensions $N_t = 5,6,7,8$\nare extrapolated to the continuum limit. The continuum results at fixed $N_c$\nare then extrapolated to $N_c = \\infty$. We find that our data are accurately\ndescribed by the formula $T_c/\\sqrt{\\sigma} = 0.5949(17) + 0.458(18)/N_c^2$.\nPossible systematic errors affecting our calculations are also discussed.",
        "positive": "Three-Nucleon Forces explored by Lattice QCD Simulations: We explore three-nucleon forces (3NF) from lattice QCD simulations. Utilizing\nthe Nambu-Bethe-Salpeter (NBS) wave function, two-nucleon forces (2NF) and 3NF\nare determined on the same footing. Quantum numbers of the three-nucleon (3N)\nsystem are chosen to be (I, J^P)=(1/2,1/2^+) (the triton channel). The enormous\ncomputational cost is reduced by employing the simplest geometrical\nconfiguration, where 3N are aligned linearly with an equal spacing. We perform\nlattice QCD simulations using Nf=2 dynamical clover fermion configurations\ngenerated by CP-PACS Collaboration, at the lattice spacing of a = 0.156 fm on a\n16^3 x 32 lattice with a large quark mass corresponding to m(\\pi) = 1.13 GeV.\nRepulsive 3NF is found at short distance."
    },
    {
        "anchor": "Comparing conserved charge fluctuations from lattice QCD to HRG model\n  calculations: We present results from lattice QCD calculations for $2^{nd}$ and $4^{th}$\norder cumulants of conserved charge fluctuations and correlations, and compare\nthese with various HRG model calculations. We show that differences between HRG\nand QCD calculations already show up in the second order cumulants close to the\npseudo-critical temperature for the chiral transition in (2+1)-flavor QCD and\nquickly grow large at higher temperatures. We also show that QCD results for\nstrangeness fluctuations are enhanced over HRG model calculations which are\nbased only on particles listed in the Particle Data Group tables as 3-star\nresonances. This suggests the importance of contributions from additional\nstrange hadron resonances. We furthermore argue that additional (repulsive)\ninteractions, introduced either through excluded volume (mean field) HRG models\nor the S-matrix approach, do not improve the quantitative agreement with\n$2^{nd}$ and $4^{th}$ order cumulants calculated in lattice QCD. HRG based\napproaches fail to describe the thermodynamics of strongly interacting matter\nat or shortly above the pseudo-critical temperature of QCD.",
        "positive": "On a mean field approximation for Higgs-Yukawa systems: We discuss the phase structure of a lattice Higgs-Yukawa system in the\nvariational mean field approximation with contributions of fermionic\ndeterminant being calculated in a ladder approximation. In particular, we\ndemonstrate that in this approximation the ferrimagnetic phase in the $Z_2$\nmodel with naive fermions can appear as an artifact of a finite lattice and\nthat the phase diagram for this model on infinite lattice changes qualitatively\nat space-time dimension $D = 4$ compared with those at $D > 4$."
    },
    {
        "anchor": "A strange property of lattices with an even number of sites: By examining the behaviour of the \"SLAC\" lattice derivative operators, it is\nfound that lattices with an even number of sites have a somewhat strange\nself-consistency requirement for extra structure in the spatial derivative\noperator, which is not needed by lattices having an odd number of sites, and\nwhich is not at all obvious from a first-principles derivation. The general\nimplications of this extra required structure are not, as yet, completely\nclear.",
        "positive": "Composite (Goldstone) Higgs Dynamics on the Lattice: Spectrum of SU(2)\n  Gauge Theory with two Fundamental Fermions: We study the meson spectrum of the SU(2) gauge theory with two Wilson\nfermions in the fundamental representation. The theory unifies both Technicolor\nand composite Goldstone Boson Higgs models of electroweak symmetry breaking. We\nhave calculated the masses of the lightest spin one vector and axial vector\nmesons. In addition, we have also obtained preliminary results for the mass of\nthe lightest scalar (singlet) meson state. The simulations have been done with\nmultiple masses and two different lattice spacings for chiral and continuum\nextrapolations. The spin one meson masses set lower limits for accelerator\nexperiments, whereas the scalar meson will mix with a pGB of the theory and\nproduce two scalar states. The lighter of the states is the 125 GeV Higgs\nboson, and the heavier would be a new yet unobserved scalar state."
    },
    {
        "anchor": "Dense 2-color QCD towards continuum and chiral limits: We study two-color QCD with two flavors of Wilson fermion as a function of\nquark chemical potential mu and temperature T, for two different lattice\nspacings and two different quark masses. We find that the quarkyonic region,\nwhere the behaviour of the quark number density and the diquark condensate are\ndescribed by a Fermi sphere of almost free quarks distorted by a BCS gap,\nextends to larger chemical potentials with decreasing lattice spacing or quark\nmass. In both cases, the quark number density also approaches its\nnon-interacting value. The pressure at low temperature is found to approach the\nStefan-Boltzmann limit from below.",
        "positive": "Towards learning optimized kernels for complex Langevin: We present a novel strategy aimed at restoring correct convergence in complex\nLangevin simulations. The central idea is to incorporate system-specific prior\nknowledge into the simulations, in order to circumvent the NP-hard sign\nproblem. In order to do so, we modify complex Langevin using kernels and\npropose the use of modern auto-differentiation methods to learn optimal kernel\nvalues. The optimization process is guided by functionals encoding relevant\nprior information, such as symmetries or Euclidean correlator data. Our\napproach recovers correct convergence in the non-interacting theory on the\nSchwinger-Keldysh contour for any real-time extent. For the strongly coupled\nquantum anharmonic oscillator we achieve correct convergence up to three-times\nthe real-time extent of the previous benchmark study. An appendix sheds light\non the fact that for correct convergence not only the absence of boundary\nterms, but in addition the correct Fokker-Plank spectrum is crucial."
    },
    {
        "anchor": "pyerrors: a python framework for error analysis of Monte Carlo data: We present the pyerrors python package for statistical error analysis of\nMonte Carlo data. Linear error propagation using automatic differentiation in\nan object oriented framework is combined with the $\\Gamma$-method for a\nreliable estimation of autocorrelation times. Data from different sources can\neasily be combined, keeping the information on the origin of error components\nintact throughout the analysis. pyerrors can be smoothly integrated into the\nexisting scientific python ecosystem which allows for efficient and compact\nanalyses.",
        "positive": "Fermion loop simulation of the lattice Gross-Neveu model: We present a numerical simulation of the Gross-Neveu model on the lattice\nusing a new representation in terms of fermion loops. In the loop\nrepresentation all signs due to Pauli statistics are eliminated completely and\nthe partition function is a sum over closed loops with only positive weights.\nWe demonstrate that the new formulation allows to simulate volumes which are\ntwo orders of magnitude larger than those accessible with standard methods."
    },
    {
        "anchor": "Disconnected Quark Loop Contributions to Nucleon Structure: We calculate the disconnected contribution to isoscalar nucleon charges for\nscalar, axial and tensor channels of light and strange quarks. The calculation\nhas been done with the Clover valence quarks on the MILC $N_f=2+1+1$ HISQ\nlattices whose light quark masses corresponding to the pion masses of 305 MeV\nand 217 MeV at $a \\approx 0.12$ fm and 312 MeV at $a \\approx 0.09$ fm.\nAll-mode-averaging technique is used for the evaluation two-point functions.\nDisconnected quark loops are estimated by using the truncated solver method\nwith Gaussian random noise sources. Contamination from the excited states is\nremoved by fitting the results of various source-sink separations and operator\ninsertions to the formula including up to the first excited state,\nsimultaneously.",
        "positive": "A note on improved stochastic trace estimation for fermionic string\n  fluctuations: We report on the use of a stochastic trace estimator algorithm, based on\nmutually unbiased bases, for evaluating the trace of a matrix differential\noperator appearing in the context of lattice simulations for the discretized\nsuperstring worldsheet. A study of the variance, in a setup which is slightly\nmodified with respect to the original one, confirms advantages with respect to\nmore traditional methods like the Gaussian estimator."
    },
    {
        "anchor": "Lattice study on the twisted ${\\mathbb C}P^{N-1}$ models on ${\\mathbb\n  R}\\times S^{1}$: We report the results of the lattice simulation of the ${\\mathbb C} P^{N-1}$\nsigma model on $S_{s}^{1}$(large) $\\times$ $S_{\\tau}^{1}$(small). We take a\nsufficiently large ratio of the circumferences to approximate the model on\n${\\mathbb R} \\times S^1$. For periodic boundary condition imposed in the\n$S_{\\tau}^{1}$ direction, we show that the expectation value of the Polyakov\nloop undergoes a deconfinement crossover as the compactified circumference is\ndecreased, where the peak of the associated susceptibility gets sharper for\nlarger $N$. For ${\\mathbb Z}_{N}$ twisted boundary condition, we find that,\neven at relatively high $\\beta$ (small circumference), the regular $N$-sided\npolygon-shaped distributions of Polyakov loop leads to small expectation values\nof Polyakov loop, which implies unbroken ${\\mathbb Z}_{N}$ symmetry if\nsufficient statistics and large volumes are adopted. We also argue the\nexistence of fractional instantons and bions by investigating the dependence of\nthe Polyakov loop on $S_{s}^{1}$ direction, which causes transition between\n${\\mathbb Z}_{N}$ vacua.",
        "positive": "Continuum Limit of Overlap Valence Quarks on a Twisted Mass Sea: We study a lattice QCD mixed action with overlap valence quarks on two\nflavours of Wilson maximally twisted mass sea quarks. Employing three different\nmatching conditions to relate both actions to each other, we investigate the\ncontinuum limit by using three values of the lattice spacing ranging from 0.05\nfm to 0.08 fm. A particular emphasis is put on the effect on physical\nobservables of the topological zero modes appearing in the valence overlap\noperator. We estimate the region of parameter space where the contribution from\nthese zero modes is sufficiently small such that their effects can be safely\ncontrolled and a restoration of unitarity of the mixed action in the continuum\nlimit is reached."
    },
    {
        "anchor": "Excited State Nucleon Spectrum with Two Flavors of Dynamical Fermions: Highly excited states for isospin 1/2 baryons are calculated for the first\ntime using lattice QCD with two flavors of dynamical quarks. Anisotropic\nlattices are used with two pion masses: 416(36) MeV and 578(29) MeV. The lowest\nfour energies are reported in each of the six irreducible representations of\nthe octahedral group at each pion mass. The lattices used have dimensions\n24^3x64, spatial lattice spacing a_s = 0.11 fm and temporal lattice spacing a_t\n= 1/3 a_s. Clear evidence is found for a 5/2^-state in the pattern of\nnegative-parity excited states. This agrees with the pattern of physical states\nand spin 5/2 has been realized for the first time on the lattice.",
        "positive": "The role of multigrid algorithms for LQCD: We report on the first successful QCD multigrid algorithm which demonstrates\nconstant convergence rates independent of quark mass and lattice volume for the\nWilson Dirac operator. The new ingredient is the adaptive method for\nconstructing the near null space on which the coarse grid multigrid Dirac\noperator acts. In addition we speculate on future prospects for extending this\nalgorithm to the Domain Wall and Staggered discretizations, its exceptional\nsuitability for high performance GPU code and its potential impact on\nsimulations at the physical pion mass."
    },
    {
        "anchor": "First results from the asymmetric O(a) improved Fermilab action: We present first results from calculations using O(a) improved (FNAL)\nspace-time asymmetric action on a 12^3 x 24 quenched lattice at \\beta = 5.7 and\nc_SW = 1.57. The asymmetry parameter is determined non-perturbatively from the\nenergy-momentum dispersion relation. This improvement scheme is mass dependent,\nand the calculations have been done in the charm and bottom quark mass sectors\nsince it is at these heavier masses that the asymmetry is expected to be\nrelevant.",
        "positive": "Approaching the Continuum Limit of the Deconfinement Critical Point for\n  $N_\\text{f}=2$ Staggered Fermions: Quenched QCD at zero baryonic chemical potential undergoes a first-order\ndeconfinement phase transition at a critical temperature $T_c$, which is\nrelated to the spontaneous breaking of the global center symmetry. The center\nsymmetry is broken explicitly by including dynamical quarks, which weaken the\nfirst-order phase transition for decreasing quark masses. At a certain critical\nquark mass, which corresponds to the $Z(2)$-critical point, the first-order\nphase transition turns into a smooth crossover. We investigate the\n$Z(2)$-critical quark mass for $N_\\text{f}=2$ staggered fermions on $N_\\tau=8,\n10$ lattices, where larger $N_\\tau$ correspond to finer lattices. Monte-Carlo\nsimulations are performed for several quark mass values and aspect ratios in\norder to extrapolate to the thermodynamic limit. We present final results for\n$N_\\tau=8$ and preliminary results for $N_\\tau=10$ for the critical mass, which\nare obtained from fitting to a kurtosis finite size scaling formula of the\nabsolute value of the Polyakov loop."
    },
    {
        "anchor": "Charged multi-hadron systems in lattice QCD+QED: Systems with the quantum numbers of up to twelve charged and neutral\npseudoscalar mesons, as well as one-, two-, and three-nucleon systems, are\nstudied using dynamical lattice quantum chromodynamics and quantum\nelectrodynamics (QCD+QED) calculations and effective field theory. QED effects\non hadronic interactions are determined by comparing systems of charged and\nneutral hadrons after tuning the quark masses to remove strong isospin breaking\neffects. A non-relativistic effective field theory, which perturbatively\nincludes finite-volume Coulomb effects, is analyzed for systems of multiple\ncharged hadrons and found to accurately reproduce the lattice QCD+QED results.\nQED effects on charged multi-hadron systems beyond Coulomb photon exchange are\ndetermined by comparing the two- and three-body interaction parameters\nextracted from the lattice QCD+QED results for charged and neutral multi-hadron\nsystems.",
        "positive": "Distillation at High-Momentum: Extraction of hadronic observables at finite-momenta from Lattice QCD (LQCD)\nis constrained by the well-known signal-to-noise problems afflicting all such\nLQCD calculations. Traditional quark smearing algorithms are commonly used\ntools to improve the statistical quality of hadronic $n$-point functions,\nprovided operator momenta are small. The momentum smearing algorithm of Bali et\nal. extends the range of momenta that are cleanly accessible, and has\nfacilitated countless novel lattice calculations. Momentum smearing has,\nhowever, not been explicitly demonstrated within the framework of distillation.\nIn this work we extend the momentum-smearing idea, by exploring a few\nmodifications to the distillation framework. Together with enhanced time slice\nsampling and expanded operator bases engendered by distillation, we find\nground-state nucleon energies can be extracted reliably for\n$\\left|\\vec{p}\\right|\\lesssim3\\text{ GeV}$ and matrix elements featuring a\nlarge momentum dependence can be resolved."
    },
    {
        "anchor": "Spin-spin correlation functions of spin systems coupled to 2-d quantum\n  gravity for $0 < c < 1$: We perform Monte Carlo simulations of 2-d dynamically triangulated surfaces\ncoupled to Ising and three--states Potts model matter. By measuring spin-spin\ncorrelation functions as a function of the geodesic distance we provide\nsubstantial evidence for a diverging correlation length at $\\beta_c$. The\ncorresponding scaling exponents are directly related to the KPZ exponents of\nthe matter fields as conjectured in [4] (NPB454(1995)313).",
        "positive": "Compact U(1)xU(1) Model with Minimal Interspecies Interaction: We introduce a minimally interacting pure gauge compact U(1)xU(1) model\nconsistent with abelian projection symmetries. This paradigm, whose\ninteractions are entirely due to compactness, illustrates how compactness can\ncontribute to interspecies interactions. Furthermore, it has a much richer\nphase structure(including a magnetically confining phase) than obtained by\nnaively tensoring together two compact U(1) copies."
    },
    {
        "anchor": "String Tension Scaling in High-Temperature Confined SU(N) Gauge Theories: SU(N) gauge theories, extended with adjoint fermions having periodic boundary\nconditions, are confining at high temperature for sufficiently light fermion\nmass $m$. In the high temperature confining region, the one-loop effective\npotential for Polyakov loops has a Z(N)-symmetric confining minimum. String\ntensions associated with Polyakov loops are calculable in perturbation theory,\nand display a novel scaling behavior in which higher representations have\nsmaller string tensions than the fundamental representation. In the magnetic\nsector, the Polyakov loop plays a role similar to a Higgs field, leading to an\napparent breaking of SU(N) to $U(1)^{N-1}$. This is turn yields a dual\neffective theory where magnetic monopoles give rise to string tensions for\nspatial Wilson loops. The spatial string tensions are calculable\nsemiclassically from kink solutions of the dual system. We show that the\nspatial string tensions $\\sigma^{(s)}_k$ associated with each $N$-ality $k$\nobey a variant of Casimir scaling $\\sigma^{(s)}_k /\\sigma^{(s)}_1 \\leq\n\\sqrt{k(N-k)/(N-1)} $. Although lattice simulations indicate that the high\ntemperature confining region is smoothly connected to the confining region of\nlow-temperature pure SU(N) gauge theory, the electric and magnetic string\ntension scaling laws are different and readily distinguishable.",
        "positive": "Direct CP violation and the $\u0394I=1/2$ rule in $K\\to\u03c0\u03c0$ decay\n  from the Standard Model: We present a lattice QCD calculation of the $\\Delta I=1/2$, $K\\to\\pi\\pi$\ndecay amplitude $A_0$ and $\\varepsilon'$, the measure of direct CP-violation in\n$K\\to\\pi\\pi$ decay, improving our 2015 calculation of these quantities. Both\ncalculations were performed with physical kinematics on a $32^3\\times 64$\nlattice with an inverse lattice spacing of $a^{-1}=1.3784(68)$ GeV. However,\nthe current calculation includes nearly four times the statistics and numerous\ntechnical improvements allowing us to more reliably isolate the $\\pi\\pi$\nground-state and more accurately relate the lattice operators to those defined\nin the Standard Model. We find ${\\rm Re}(A_0)=2.99(0.32)(0.59)\\times 10^{-7}$\nGeV and ${\\rm Im}(A_0)=-6.98(0.62)(1.44)\\times 10^{-11}$ GeV, where the errors\nare statistical and systematic, respectively. The former agrees well with the\nexperimental result ${\\rm Re}(A_0)=3.3201(18)\\times 10^{-7}$ GeV. These results\nfor $A_0$ can be combined with our earlier lattice calculation of $A_2$ to\nobtain ${\\rm Re}(\\varepsilon'/\\varepsilon)=21.7(2.6)(6.2)(5.0) \\times 10^{-4}$,\nwhere the third error represents omitted isospin breaking effects, and\nRe$(A_0)$/Re$(A_2) = 19.9(2.3)(4.4)$. The first agrees well with the\nexperimental result of ${\\rm Re}(\\varepsilon'/\\varepsilon)=16.6(2.3)\\times\n10^{-4}$. A comparison of the second with the observed ratio Re$(A_0)/$Re$(A_2)\n= 22.45(6)$, demonstrates the Standard Model origin of this \"$\\Delta I = 1/2$\nrule\" enhancement."
    },
    {
        "anchor": "On the phase diagram of QCD at finite isospin density: Using a canonical formalism, we determine the equation of state and the phase\ndiagram of eight-flavour QCD, as a function of temperature and isospin density.\nTwo mechanisms are at work: Bose condensation of pions at high density, and\ndeconfinement at high temperature. We study their interplay and find that on\nour small and coarse lattice the first order deconfinement transition appears\nto end at a critical point at finite density. We investigate the strength of\nthe overlap and of the sign problems and discuss implications for the baryonic\ndensity case.",
        "positive": "Precision lattice QCD computation of the $B^*B\u03c0$ coupling: The static $B^{*}B\\pi$ coupling, $\\hat{g}_\\chi$, a low energy constant in the\nleading order heavy meson chiral Lagrangian, is determined using $N_\\mathrm{f}\n= 2$ lattice QCD. We use CLS ensembles with lattice spacings and pion masses\ndown to $a = 0.05\\mathrm{fm}$ and $m_{\\pi}=270\\mathrm{MeV}$, and perform\ncombined continuum and chiral extrapolations of our results which have a much\nbetter accuracy than previous numbers in the literature. As a by-product, we\ndetermine the coupling between the first radial excitations in the $B$ and\n$B^{*}$ channels ($\\hat{g}_{22}$). Accounting for all uncertainties, which are\ndominated by the chiral extrapolation, we obtain $\\hat{g}_\\chi = 0.492(29)$,\nwhile $\\hat{g}_{22}$ is somewhat smaller. The comparison to a precise quenched\ncomputation suggests that there is little influence by the sea quarks and\n$\\hat{g}_\\chi$ will not change much when a dynamical strange quark is included."
    },
    {
        "anchor": "The Ising transition in 2D simplicial quantum gravity - can Regge\n  calculus be right?: We report a high statistics simulation of Ising spins coupled to 2D quantum\ngravity in the Regge calculus approach using triangulated tori with up to\n$512^2$ vertices. For the constant area ensemble and the $dl/l$ functional\nmeasure we definitively can exclude the critical exponents of the Ising phase\ntransition as predicted for dynamically triangulated surfaces. We rather find\nclear evidence that the critical exponents agree with the Onsager values for\nstatic regular lattices, independent of the coupling strength of an $R^2$\ninteraction term. For exploratory simulations using the lattice version of the\nMisner measure the situation is less clear.",
        "positive": "k-String Tensions and Center Vortices at Large N: We point out that there is a natural explanation, in terms of the center\nvortex confinement mechanism, for the expected Casimir/Sine Law scaling of\nk-string tensions in the large N limit. The crucial ingredient is the existence\nof Z(N) center monopoles, which go over to U(1) monopoles in this limit. Vortex\ndensities leading to Casimir/Sine Law scaling at large-N are constructed; these\ndensities have no obvious pathologies and in particular do not grow with N. We\nalso note that center vortices are stable classical solutions of the Wilson\naction, for all SU(N) gauge theories with N>4, and extend this old result to a\nbroad class of lattice actions motivated by the improved action program and the\nrenormalization group."
    },
    {
        "anchor": "Form factors for the processes $B_c^+ \\to D^0 \\ell^+ \u03bd_{\\ell}$ and\n  $B_c^+ \\to D_s^+ \\ell^+ \\ell^- (\u03bd\\overline\u03bd)$ from lattice QCD: We present results of the first lattice QCD calculations of the weak matrix\nelements for the decays $B_c^+ \\to D^0 \\ell^+ \\nu_{\\ell}$, $B_c^+ \\to D_s^+\n\\ell^+ \\ell^-$ and $B_c^+ \\to D_s^+ \\nu \\overline{\\nu}$. Form factors across\nthe entire physical $q^2$ range are then extracted and extrapolated to the\ncontinuum limit with physical quark masses. Results are derived from\ncorrelation functions computed on MILC Collaboration gauge configurations with\nthree different lattice spacings and including 2+1+1 flavours of sea quarks in\nthe Highly Improved Staggered Quark (HISQ) formalism. HISQ is also used for all\nof the valence quarks. The uncertainty on the decay widths from our form\nfactors is similar in size to that from the present value for $V_{ub}$. We\nobtain the ratio $\\Gamma (B_{c}^{+} \\rightarrow D^0 \\mu^{+} \\nu_{\\mu})\n/\\left|\\eta_{\\mathrm{EW}} V_{u b}\\right|^{2}=4.43(63) \\times 10^{12}\n\\mathrm{~s}^{-1}$. Combining our form factors with those found previously by\nHPQCD for $B_{c}^{+} \\rightarrow J / \\psi \\mu^{+} \\nu_{\\mu}$, we find\n$\\left|V_{cb}/V_{ub} \\right|^2 \\Gamma( B_c^+ \\to D^0 \\mu^+ \\nu_\\mu\n)/\\Gamma(B_{c}^{+} \\rightarrow J / \\psi \\mu^{+} \\nu_{\\mu}) = 0.257(36)_{B_c \\to\nD}(18)_{B_c \\to J/\\psi}$. We calculate the differential decay widths of $B_c^+\n\\to D_s^+ \\ell^+ \\ell^-$ across the full $q^2$ range, and give integrated\nresults in $q^2$ bins that avoid possible effects from charmonium and $u\n\\overline{u}$ resonances. For example, we find that the ratio of differential\nbranching fractions integrated over the range $q^2 = 1 \\; \\mathrm{GeV}^2 - 6 \\;\n\\mathrm{GeV}^2$ for $B_c^+ \\to D_s^+ \\mu^+ \\mu^-$ and $B_{c}^{+} \\rightarrow J\n/ \\psi \\mu^{+} \\nu_{\\mu}$ is $5.23{\\tiny }(73)_{B_c \\to D_s}(54)_{B_c \\to\nJ/\\psi} \\times 10^{-6}$. We also give results for the branching fraction of\n$B_c^+ \\to D_s^+ \\nu \\overline{\\nu}$. Prospects for reducing our errors in the\nfuture are discussed.",
        "positive": "The leading hadronic contribution to $(g-2)_\u03bc$ from lattice QCD with\n  $N_{\\rm f}=2+1$ flavours of O($a$) improved Wilson quarks: The comparison of the theoretical and experimental determinations of the\nanomalous magnetic moment of the muon $(g-2)_\\mu$ constitutes one of the\nstrongest tests of the Standard Model at low energies. In this article, we\ncompute the leading hadronic contribution to $(g-2)_\\mu$ using lattice QCD\nsimulations employing Wilson quarks. Gauge field ensembles at four different\nlattice spacings and several values of the pion mass down to its physical value\nare used. We apply the O($a$) improvement programme with two discretizations of\nthe vector current to better constrain the approach to the continuum limit. The\nelectromagnetic current correlators are computed in the time-momentum\nrepresentation. In addition, we perform auxiliary calculations of the pion form\nfactor at timelike momenta in order to better constrain the tail of the\nisovector correlator and to correct its dominant finite-size effect. For the\nnumerically dominant light-quark contribution, we have rescaled the lepton mass\nby the pion decay constant computed on each lattice ensemble. We perform a\ncombined chiral and continuum extrapolation to the physical point, and our\nfinal result is $ a_\\mu^{\\rm hvp}=(720.0\\pm12.4_{\\rm stat}\\,\\pm9.9_{\\rm\nsyst})\\cdot10^{-10}$. It contains the contributions of quark-disconnected\ndiagrams, and the systematic error has been enlarged to account for the missing\nisospin-breaking effects."
    },
    {
        "anchor": "A novel Bayesian approach to spectral function reconstruction: We present a novel approach to the inference of spectral functions from\nEuclidean time correlator data that makes close contact with modern Bayesian\nconcepts. Our method differs significantly from the maximum entropy method\n(MEM). A new set of axioms is postulated for the prior probability, leading to\nan improved expression, which is devoid of the asymptotically flat directions\npresent in the Shanon-Jaynes entropy. Hyperparameters are integrated out\nexplicitly, liberating us from the Gaussian approximations underlying the\nevidence approach of the MEM. We present a realistic test of our method in the\ncontext of the non-perturbative extraction of the heavy quark potential. Based\non hard-thermal-loop correlator mock data, we establish firm requirements in\nthe number of data points and their accuracy for a successful extraction of the\npotential from lattice QCD. An improved potential estimation from previously\ninvestigated quenched lattice QCD correlators is provided.",
        "positive": "Light pseudoscalar meson masses and decay constants from mixed action\n  lattice QCD: We calculate the light pseudoscalar decay constants, f_pi and f_K, and their\nratio using domain wall valence quarks and 2+1 flavors of dynamical staggered\nquarks. Use of the MILC gauge configurations allows us to simulate at several\nsea quark masses and spatial volumes, and with two lattice spacings. We study\nhow well our numerical lattice data for light decay constants and meson masses\nis described by next-to-leading order SU(3) mixed action chiral perturbation\ntheory and explain our strategy for the chiral and continuum extrapolation.\nCombining our result for f_K/f_pi with experimental measurements of pion and\nkaon leptonic decays allows a model-independent determination of |V_us|/|V_ud|;\nwe find a preliminary value of |V_us|/|V_ud| = 0.2315(45)(7)."
    },
    {
        "anchor": "A calculation of the Lepage-Mackenzie scale for the lattice axial and\n  vector currents: We calculate the perturbative scales (q*) for the axial and vector currents\nfor the Wilson action, with and without tadpole improvement, using Lepage and\nMackenzie's formalism. The scale for the pseudoscalar density (times the mass)\nis computed as well. Contrary to naive expectation, tadpole improvement reduces\nq* by only a small amount for the operators we consider. We also discuss the\nuse of a nonperturbative coupling to calculate the perturbative scale.",
        "positive": "Coupled-Channel $D\u03c0$, $D\u03b7$ and $D_{s}\\bar{K}$ Scattering from\n  Lattice QCD: We present the first lattice QCD study of coupled-channel $D\\pi$, $D\\eta$ and\n$D_{s}\\bar{K}$ scattering in isospin-1/2 in three partial waves. Using\ndistillation, we compute matrices of correlation functions with bases of\noperators capable of resolving both meson and meson-meson contributions to the\nspectrum. These correlation matrices are analysed using a variational approach\nto extract the finite-volume energy eigenstates. Utilising L\\\"uscher's method\nand its extensions, we constrain scattering amplitudes in $S$, $P$ and $D$-wave\nas a function of energy. By analytically continuing the scattering amplitudes\nto complex energies, we investigate the $S$-matrix singularities. Working at\n$m_\\pi \\approx 391$ MeV, we find a pole corresponding to a $J^{P} = 0^{+}$\nnear-threshold bound state with a large coupling to $D\\pi$. We also find a\ndeeply bound $J^{P} = 1^{-}$ state, and evidence for a $J^{P} = 2^{+}$ narrow\nresonance coupled predominantly to $D\\pi$. Elastic $D\\pi$ scattering in the\nisospin-$3/2$ channel is studied and we find a weakly repulsive interaction in\n$S$-wave."
    },
    {
        "anchor": "B meson decays at high velocity from mNRQCD: The moving NRQCD (mNRQCD) formalism facilitates the simulation of heavy meson\ndecays at large recoil. We present preliminary results for a number of\nquantities including the energy splittings and the $B$ meson decay constant\nthat demonstrate that the formalism is accurate over a range of momenta.",
        "positive": "First dynamical simulations with minimally doubled fermions: For thermodynamics studies it is desirable to simulate two degenerate flavors\nand retain at least a remnant of the chiral symmetry. Staggered fermions can\nachieve this at the cost of rooting the determinant. Rooting can be avoided\nusing minimally doubled fermions. This discretization describes two degenerate\nquark flavors while explicitly breaking hyper-cubic symmetry, thus, requiring\nadditional counter-terms. We use one particular formulation of minimally\ndoubled fermions called the Kirsten-Wilczek action and mitigate lattice\nartifacts by improving the spatial derivatives in the Dirac operator. In this\npilot study we determine the counter-terms non-perturbatively to facilitate\nproper dynamical simulations."
    },
    {
        "anchor": "SO(4), SO(3) and SU(2) gauge theories in 2+1 dimensions: comparing\n  glueball spectra and string tensions: We improve upon recent calculations of the low-lying `glueball' spectra of\nSO(3) and SO(4) lattice gauge theories in 2+1 dimensions, and compare the\nresulting continuum extrapolations with SU(2). We find that these are\nreasonably consistent, as are the SU(2) and SO(4) string tensions when these\nare corrected for the differing representations of the flux. All this indicates\nthat the different global properties of these groups do not play a significant\nrole in the low-lying physics.",
        "positive": "No evidence for bilinear condensate in parity-invariant\n  three-dimensional QED with massless fermions: We present our numerical study of three-dimensional QED with 2, 4, 6 and 8\nflavors of massless two-component fermions using a parity-preserving lattice\nregularization with Wilson fermions. We study the behavior of low-lying\neigenvalues of the massless improved Wilson-Dirac operator as a function of\nthree-dimensional physical volume, after taking the continuum limit at fixed\nphysical volumes. We find the following evidences against the presence of\nbilinear condensate: the eigenvalues do not scale as the inverse of the\nthree-dimensional physical volume, and the number variance associated with\nthese eigenvalues do not exhibit ergodic behavior. The inverse participation\nratio (IPR) of the associated eigenvectors exhibits a multi-fractal volume\nscaling. The relation satisfied by number variance and IPR suggests critical\nbehavior."
    },
    {
        "anchor": "Extension of the HAL QCD approach to inelastic and multi-particle\n  scatterings in lattice QCD: We extend the HAL QCD approach, with which potentials between two hadrons can\nbe obtained in QCD at energy below inelastic thresholds, to inelastic and\nmulti-particle scatterings. We first derive asymptotic behaviors of the\nNambu-Bethe-Salpeter (NBS) wave function at large space separations for systems\nwith more than 2 particles, in terms of the one-shell $T$-matrix consrainted by\nthe unitarity of quantum field theories. We show that its asymptotic behavior\ncontains phase shifts and mixing angles of $n$ particle scatterings. This\nproperty is one of the essential ingredients of the HAL QCD scheme to define\n\"potential\" from the NBS wave function in quantum field theories such as QCD.\nWe next construct energy independent but non-local potentials above inelastic\nthresholds, in terms of these NBS wave functions. We demonstrate an existence\nof energy-independent coupled channel potentials with a non-relativistic\napproximation, where momenta of all particles are small compared with their own\nmasses. Combining these two results, we can employ the HAL QCD approach also to\ninvestigate inelastic and multi-particle scatterings.",
        "positive": "Moments of Isovector Quark Distributions in Lattice QCD: We investigate the connection of lattice calculations of moments of isovector\nparton distributions to the physical regime through extrapolations in the quark\nmass. We consider the one pion loop renormalisation of the nucleon matrix\nelements of the corresponding operators and thereby develop formulae with which\nto extrapolate the moments of the unpolarised, helicity and transversity\ndistributions. These formulae are consistent with chiral perturbation theory in\nthe chiral limit and incorporate the correct heavy quark limits. In the\npolarised cases, the inclusion of intermediate states involving the $\\Delta$\nisobar is found to be very important. The results of our extrapolations are in\ngeneral agreement with the phenomenological values of these moments where they\nare known, and for the first time we perform an extrapolation of the low\nmoments of the isovector transversity distribution which is consistent with\nchiral symmetry."
    },
    {
        "anchor": "Overlap Dirac operator at nonzero chemical potential and random matrix\n  theory: We show how to introduce a quark chemical potential in the overlap Dirac\noperator. The resulting operator satisfies a Ginsparg-Wilson relation and has\nexact zero modes. It is no longer gamma_5-hermitian, but its nonreal\neigenvalues still occur in pairs. We compute the spectral density of the\noperator on the lattice and show that, for small eigenvalues, the data agree\nwith analytical predictions of nonhermitian chiral random matrix theory for\nboth trivial and nontrivial topology.",
        "positive": "Monte Carlo study of very weak first-order transitions in the\n  three-dimensional Ashkin-Teller model: We propose numerical simulations of the Ashkin-Teller model as a foil for\ntheoretical techniques for studying very weakly first-order phase transitions\nin three dimensions. The Ashkin-Teller model is a simple two-spin model whose\nparameters can be adjusted so that it has an arbitrarily weakly first-order\nphase transition. In this limit, there are quantities characterizing the\nfirst-order transition which are universal: we measure the relative\ndiscontinuity of the specific heat, the correlation length, and the\nsusceptibility across the transition by Monte Carlo simulation."
    },
    {
        "anchor": "Gauge fixing and gluon propagator in lambda-gauges: We discuss critical slowing-down of several gauge-fixing algorithms for the\nso-called lambda-gauges in the SU(2) case at zero temperature. For these gauges\nwe also evaluate the gluon propagator using different definitions of the\nlattice gluon field, corresponding to discretization errors of different\norders.",
        "positive": "Gluon screening mass at finite temperature from Landau gauge gluon\n  propagator in lattice QCD: We address the interpretation of the Landau gauge gluon propagator at finite\ntemperature as a massive type bosonic propagator. Using pure gauge SU(3)\nlattice simulations at a fixed lattice volume $\\sim(6.5fm)^3$, we compute the\nelectric and magnetic form factors, extract a gluon mass from Yukawa-like fits,\nand study its temperature dependence. This is relevant both for the Debye\nscreening at high temperature $T$ and for confinement at low $T$."
    },
    {
        "anchor": "Calculation of neutron electric dipole moment due to the QCD topological\n  term, Weinberg three-gluon operator and the quark chromoelectric moment: We present results for the neutron electric dipole moment due to the\ndimension 4 and dimension 6 gluonic CP violation, and the isovector quark\nchromoelectric dipole moment using clover valence quarks on HISQ dynamical\nensembles generated by the MILC Collaboration. For the gluonic operators, we\nuse the gradient flow scheme to obtain divergence-free continuum results. For\nthe chromoelectric dipole moment operator, we use the unflowed local operator\nbut discuss how the quadratically divergent mixing with the pseudoscalar\noperator can be controlled nonperturbatively.",
        "positive": "Calculating $\u0394m_K$ with lattice QCD: We have completed a lattice QCD calculation of $\\Delta m_K$, the mass\ndifference between the long- and short-lived K mesons. The calculation was\nperformed on a $64^3 \\times 128$ lattice using 152 configurations with physical\nquark masses and an inverse lattice spacing of $1/a=2.36$ GeV. While the\nstatistical error approaches a relatively small size of 9%, several sources of\nsystematic errors may have more significant effects. In this paper we will\naddress studies performed on smaller lattices to estimate the systematic errors\nin our result."
    },
    {
        "anchor": "Forces between composite particles in QCD: Starting from the meson-meson Green function in 3+1 dimensional quenched\nlattice QCD we calculate potentials between heavy-light mesons for various\nlight-quark mass parameters. For the valence quarks we employ the staggered\nscheme. The resulting potentials turn out to be short ranged and attractive. A\ncomparison with a tadpole improved action for the gauge fields is presented.",
        "positive": "The degeneration of critical point in Z(3)spin system. A proposal for\n  QCD confinement-deconfinement phase transition in the color space: The problem of the phase transition of a Z(3) spin system is a complex issue.\nA numerical simulation in the framework of the mean field theory using the\nMetropolis algorithm reveals: (a) the existence of second order phase\ntransition with a degenerated critical point which could be considered as a\nstate of resonance (b) hysteresis phenomena which are accompanied with\ntricritical crossover around the end point of first order transition. Based on\nthese results we propose a scenario about confinement-deconfinement phase\ntransition in SU(3) symmetry of color QCD which, as it is known, has the same\ncenter with Z(3) spin system symmetry."
    },
    {
        "anchor": "Restless pions: orbifold boundary conditions and noise suppression in\n  lattice QCD: The study of one or more baryons in lattice QCD is severely hindered by the\nexponential decay in time of the signal-to-noise ratio. The rate at which the\nsignal-to-noise decreases is a function of the the pion mass. More precisely,\nit depends on the minimum allowed pion energy in the box, which, for periodic\nboundary conditions, is equal to its mass. We propose a set of boundary\nconditions, given by a \"parity orbifold'' construction, which eliminates the\nzero momentum pion modes, raising the minimum pion energy without altering the\nQCD ground state, and thereby improving the signal-to-noise ratio of\n(multi)-baryon correlation functions at long Euclidean times. We discuss\nvariations of these \"restless pions\" boundary conditions and focus on their\nimpact on the study of nuclear forces.",
        "positive": "The finite volume spectrum of excited states from lattice QCD\n  simulations: We present results for the spectrum of excited mesons obtained from temporal\ncorrelations of spatially-extended single-hadron and multi-hadron operators\ncomputed in lattice QCD. The stochastic LapH algorithm is implemented on\nanisotropic, dynamical lattices for isovectors for pions of mass $390$ MeV. A\nlarge correlation matrix with single-particle and two-particle probe operators\nis diagonalized to identify resonances. The masses of excited states in the\n$I=1, S=0, T_{1u}^+$ channel as well as the mixing of single and multi-particle\nprobe operators are presented."
    },
    {
        "anchor": "Isospin breaking in 2+1 flavor QCD+QED: The mass splittings in the pseudoscalar mesons are studied by combining 2+1\nflavor domain wall fermion gauge configurations, generated by the RBC/UKQCD\ncollaborations, and quenched, non-compact, lattice QED configurations. We\nextract the QED low energy constants in SU(3) partially quenched chiral\nperturbation theory, up to next-to-leading order, and determine the\nnon-degenerate u, d and s quark masses. Systematic uncertainties due to chiral\nextrapolations are discussed. The chiral symmetry breaking of domain wall\nfermions on the lattice and its effect in partially quenched chiral\nperturbation theory, including QED effects, is also investigated.",
        "positive": "Identifying topological structures with adjoint filtering method: We present new investigations on the Adjoint Filtering Method (AFM), a\nproposal for filtering gauge configurations by using adjoint zero modes. This\nmethod relies on the existence of the Supersymmetric Zero Mode (SZM), whose\ndensity follows the gauge action density for classical configurations. We\nreview how a similar construction on the lattice is implemented based on the\noverlap operator and test the method against smooth configurations showing a\nremarkable agreement with the expected densities even when pairs of fractionals\ninstanton/anti-instantons are present and noise is added. Then we explore the\napplication of the method to Monte Carlo generated configurations based on\nSU(2) gauge group. The tuning of the parameters and quantitative results are\nexplicitly shown for a $T^3\\times R$ lattice. We show explicit examples\ncomparing the AFM to the density obtained from the Gradient Flow. The agreement\nis remarkable for some specific configurations containing fractional instantons\nwith the advantage that the AFM does not modify the underlying structures."
    },
    {
        "anchor": "Finite Temperature QCD on the Lattice: Recent progress in lattice QCD at finite temperature is reviewed.",
        "positive": "Large-q expansion for the second moment correlation length in the\n  two-dimensional q-state Potts model: We calculate the large-q expansion of the second moment correlation length at\nthe first order phase transition point of the q-state Potts model in two\ndimensions both in the ordered and disordered phases to order 21 in\n$1/\\sqrt{q}$. They coincide with each other to the third term of the series but\ndiffer a little in higher orders. Numerically the ratio of the second moment\ncorrelation length in the two phases is not far from unity in all region of\nq>4. The ratio of the second moment correlation length to the standard\ncorrelation length in the disordered phase is far from unity, which suggests\nthat the second largest and smaller eigenvalues of the transfer matrix form a\ncontinuum spectrum not only in the large-q region but also in all the region of\nq>4."
    },
    {
        "anchor": "Nucleon form factors with dynamical twisted mass fermions: The electromagnetic and axial form factors of the nucleon are evaluated in\ntwisted mass QCD with two degenerate flavors of light, dynamical quarks. The\naxial charge g_A, magnetic moment and the Dirac and Pauli radii are determined\nfor pion masses in the range 300 MeV to 500 MeV.",
        "positive": "Mirage in Temporal Correlation functions for Baryon-Baryon Interactions\n  in Lattice QCD: Single state saturation of the temporal correlation function is a key\ncondition to extract physical observables such as energies and matrix elements\nof hadrons from lattice QCD simulations. A method commonly employed to check\nthe saturation is to seek for a plateau of the observables for large Euclidean\ntime. Identifying the plateau in the cases having nearby states, however, is\nnon-trivial and one may even be misled by a fake plateau. Such a situation\ntakes place typically for the system with two or more baryons. In this study,\nwe demonstrate explicitly the danger from a possible fake plateau in the\ntemporal correlation functions mainly for two baryons ($\\Xi\\Xi$ and $NN$), and\nthree and four baryons ($^3{\\rm He}$ and $^4{\\rm He})$ as well, employing\n(2+1)-flavor lattice QCD at $m_{\\pi}=0.51$ GeV on four lattice volumes with\n$L=$ 2.9, 3.6, 4.3 and 5.8 fm. Caution is given for drawing conclusion on the\nbound $NN$, $3N$ and $4N$ systems only based on the temporal correlation\nfunctions."
    },
    {
        "anchor": "New lattice approaches to the $\u0394I=1/2$ rule: Lattice QCD should allow a derivation of the $\\Delta I=1/2$ rule from first\nprinciples, but numerical calculations to date have been plagued by a variety\nof problems. After a brief review of these problems, we present several new\nmethods for calculating $K\\to\\pi\\pi$ amplitudes. These are designed for Wilson\nfermions, though they can be used also with staggered fermions. They all\ninvolve a non-perturbative determination of matching coefficients. We show how\nproblems of operator mixing can be greatly reduced by using point-split\nhadronic currents, and how CP violating parts of the $K\\to\\pi\\pi$ amplitudes\ncan be calculated by introducing a fake top quark. Many of the methods can also\nbe applied to the calculation of two body non-leptonic B-meson decays.",
        "positive": "Photon emissivity of the quark-gluon plasma: a lattice QCD analysis of\n  the transverse channel: We present results for the thermal photon emissivity of the quark-gluon\nplasma derived from spatially transverse vector correlators computed in lattice\nQCD at a temperature of 250 MeV. The analysis of the spectral functions,\nperformed at fixed spatial momentum, is based on continuum-extrapolated\ncorrelators obtained with two flavours of dynamical Wilson fermions. We compare\nthe next-to-leading order perturbative QCD correlators, as well as the ${\\cal\nN}=4$ supersymmetric Yang-Mills correlators at infinite coupling, to the\ncorrelators from lattice QCD and find them to lie within $\\sim10\\%$ of each\nother. We then refine the comparison, performing it at the level of filtered\nspectral functions obtained model-independently via the Backus-Gilbert method.\nMotivated by these studies, for frequencies $\\omega\\lesssim2.5\\,$GeV we use fit\nans\\\"atze to the spectral functions that perform well when applied to mock data\ngenerated from the NLO QCD or from the strongly-coupled SYM spectral functions,\nwhile the high-frequency part, $\\omega\\gtrsim 2.5\\,$GeV, is matched to NLO QCD.\nWe compare our results for the photon emissivity to our previous analysis of a\ndifferent vector channel at the same temperature. We obtain the most stringent\nconstraint at photon momenta around $k\\simeq0.8\\,$GeV, for which we find a\ndifferential photon emission rate per unit volume of $d\\Gamma_\\gamma/d^3k =\n(\\alpha_{\\rm em}/(\\exp(k/T)-1))\\times (2.2 \\pm 0.8 ) \\times 10^{-3}\\,{\\rm\nGeV}$."
    },
    {
        "anchor": "Lefschetz thimbles in fermionic effective models with repulsive\n  vector-field: We discuss two problems in complexified auxiliary fields in fermionic\neffective models, the auxiliary sign problem associated with the repulsive\nvector-field and the choice of the cut for the scalar field appearing from the\nlogarithmic function. In the fermionic effective models with attractive scalar\nand repulsive vector-type interaction, the auxiliary scalar and vector fields\nappear in the path integral after the bosonization of fermion ilinears. When we\nmake the path integral well-defined by the Wick rotation of the vector field,\nthe oscillating Boltzmann weight appears in the partition function. This\n\"auxiliary\" sign problem can be solved by using the Lefschetz-thimble\npath-integral method, where the integration path is constructed in the complex\nplane. Another serious obstacle in the numerical construction of Lefschetz\nthimbles is caused by singular points and cuts induced by multivalued functions\nof the complexified scalar field in the momentum integration. We propose a new\nprescription which fixes gradient flow trajectories on the same Riemann sheet\nin the flow evolution by performing the momentum integration in the complex\ndomain.",
        "positive": "Fermion bag approach to Hamiltonian lattice field theories in continuous\n  time: We extend the idea of fermion bags to Hamiltonian lattice field theories in\nthe continuous time formulation. Using a class of models we argue that the\ntemperature is a parameter that splits the fermion dynamics into small spatial\nregions that can be used to identify fermion bags. Using this idea we construct\na continuous time quantum Monte Carlo algorithm and compute critical exponents\nin the 3d Ising Gross-Neveu universality class using a single flavor of\nmassless Hamiltonian staggered fermions. We find $\\eta$=0.54(6) and\n$\\nu$=0.88(2) using lattices up to N=2304 sites. We argue that even sizes up to\nN=10,000 sites should be accessible with supercomputers available today."
    },
    {
        "anchor": "Fits of $SU(3)$ $N_f=8$ data to dilaton-pion effective field theory: We report on fits of the $SU(3)$ $N_f=8$ LSD spectral data to chiral\nperturbation theory with a dilatonic meson. These fits confirm that current\nsimulations are in the \"large-mass\" regime, with approximate hyperscaling as\nthe leading mass dependence. We find that the leading-order effective field\ntheory describes the data well. In particular, the effective field theory\nallows us to understand the staggered taste splitting, explaining the pattern\nobserved in the LSD data, which looks different from QCD.",
        "positive": "Calculation of the running coupling in non-Abelian gauge theories from\n  Jarzynski's equality: We discuss the theoretical foundations of non-equilibrium Monte Carlo\nsimulations based on Jarzynski's equality and present, as an example of\napplication, the determination of the running coupling in the\nSchr\\\"odinger-functional scheme."
    },
    {
        "anchor": "Charm and strange hadron spectra from overlap fermions on HISQ gauge\n  configurations: We report here results on charm and strange hadron spectra.\n  Adopting a mixed action approach, we use overlap fermions for valence quarks,\non a background of 2+1+1 flavours HISQ gauge configurations of MILC\ncollaboration. Two lattice spacings (0.09 fm and 0.06 fm) are used. We find the\nhyperfine splitting of 1S charmonia to be 114(3)(-2) MeV and 109(4)(-3) MeV,\nand the splitting (m(Omega_ccc)-3/2 m(J\\Psi)) is found to be 110(20)(-10) MeV\nand 120(10) MeV, corresponding to lattices with spacings a = 0.09 and 0.06 fm\nrespectively. We also look at the ratio of the leptonic decay constant\nf_Ds*/f_Ds.",
        "positive": "Unveiling generalized parton distributions through the\n  pseudo-distribution approach: Understanding the intricate three-dimensional internal structure of the\nnucleon has been a long-standing challenge. The main quantitative tool to map\nout this structure are the generalized parton distributions (GPDs). In these\nproceedings, we present our exploratory results from applying the\npseudo-distribution approach on the lattice, showing the unpolarized isovector\n$E$ GPD as an example. We use one ensemble of $N_f=2+1+1$ twisted mass fermions\nwith a clover term, at a non-physical pion mass of $260 \\textrm{ MeV}$ and a\nlattice spacing of $0.093 \\textrm{ fm}$."
    },
    {
        "anchor": "Wilson loops with arbitrary charges: We discuss how to implement, in lattice gauge theories, external charges\nwhich are not commensurate with an elementary gauge coupling. It is shown that\nan arbitrary, real power of a standard Wilson loop (or Polyakov line) can be\ndefined and consistently computed in lattice formulation of non-abelian, two\ndimensional gauge theories. However, such an observable can excite quantum\nstates with integer fluxes only. Since the non-integer fluxes are not in the\nspectrum of the theory they cannot be created, no matter which observable is\nchosen. Also the continuum limit of above averages does not exist unless the\npowers in question are in fact integer. On the other hand, a new continuum\nlimit exists, which is rather intuitive, and where above observables make\nperfect sense and lead to the string tension proportional to the square of\narbitrary (non necessary commensurate with gauge coupling) charge.",
        "positive": "Non-abelian lattice gauge theory with a topological action: SU(2) gauge theory is investigated with a lattice action which is insensitive\nto small perturbations of the lattice gauge fields. Bare perturbation theory\ncan not be defined for such actions at all. We compare non-perturbative\ncontinuum results with that obtained by the usual Wilson plaquette action. The\ncompared observables span a wide range of interesting phenomena: zero\ntemperature large volume behavior (topological susceptibility), finite\ntemperature phase transition (critical exponents and critical temperature) and\nalso the small volume regime (discrete beta-function or step-scaling function).\nIn the continuum limit perfect agreement is found indicating that universality\nholds for these topological lattice actions as well."
    },
    {
        "anchor": "Abelian Links, Monopoles and Glueballs in SU(2) Lattice Gauge Theory: We investigate the masses of 0+ and 2+ glueballs in SU(2) lattice gauge\ntheory using abelian projection to the maximum abelian gauge. We calculate\nglueball masses using both abelian links and monopole operators. Both methods\nreproduce the known full SU(2) results quantitatively. Positivity problems\npresent in the abelian projection are discussed. We study the dependence of the\nglueball masses on magnetic current loop size, and find that the 0+ state\nrequires a much greater range of sizes than does the 2+ state.",
        "positive": "Density Induced Phase Transitions in the Schwinger Model: A Study with\n  Matrix Product States: We numerically study the zero temperature phase structure of the multiflavor\nSchwinger model at nonzero chemical potential. Using matrix product states, we\nreproduce analytical results for the phase structure for two flavors in the\nmassless case and extend the computation to the massive case, where no\nanalytical predictions are available. Our calculations allow us to locate phase\ntransitions in the mass-chemical potential plane with great precision and\nprovide a concrete example of tensor networks overcoming the sign problem in a\nlattice gauge theory calculation."
    },
    {
        "anchor": "Casimir effect with machine learning: Vacuum fluctuations of quantum fields between physical objects depend on the\nshapes, positions, and internal composition of the latter. For objects of\narbitrary shapes, even made from idealized materials, the calculation of the\nassociated zero-point (Casimir) energy is an analytically intractable\nchallenge. We propose a new numerical approach to this problem based on\nmachine-learning techniques and illustrate the effectiveness of the method in a\n(2+1) dimensional scalar field theory. The Casimir energy is first calculated\nnumerically using a Monte-Carlo algorithm for a set of the Dirichlet boundaries\nof various shapes. Then, a neural network is trained to compute this energy\ngiven the Dirichlet domain, treating the latter as black-and-white pixelated\nimages. We show that after the learning phase, the neural network is able to\nquickly predict the Casimir energy for new boundaries of general shapes with\nreasonable accuracy.",
        "positive": "Lattice supersymmetry with domain wall fermions: Supersymmetry, like Poincare symmetry, is softly broken at finite lattice\nspacing provided the gaugino mass term is strongly suppressed. Domain wall\nfermions provide the mechanism for suppressing this term by approximately\nimposing chiral symmetry. We present the first numerical simulations of N=1\nsupersymmetric SU(2) Yang-Mills on the lattice in four dimensions using domain\nwall fermions."
    },
    {
        "anchor": "Status of Lattice QCD Determination of Nucleon Form Factors and their\n  Relevance for the Few-GeV Neutrino Program: Calculations of neutrino-nucleus cross sections begin with the\nneutrino-nucleon interaction, making the latter critically important to\nflagship neutrino oscillation experiments, despite limited measurements with\npoor statistics. Alternatively, lattice QCD (LQCD) can be used to determine\nthese interactions from the Standard Model with quantifiable theoretical\nuncertainties. Recent LQCD results of $g_{\\mathrm{A}}$ are in excellent\nagreement with data, and results for the (quasi-)elastic nucleon form factors\nwith full uncertainty budgets are expected within a few years. We review the\nstatus of the field and LQCD results for the nucleon axial form factor,\n$F_{\\mathrm{A}}(Q^2)$, a major source of uncertainty in modeling sub-GeV\nneutrino-nucleon interactions. Results from different LQCD calculations are\nconsistent, but collectively disagree with existing models, with potential\nimplications for current and future neutrino oscillation experiments. We\ndescribe a road map to solidify confidence in the LQCD results and discuss\nfuture calculations of more complicated processes, important to few-GeV\nneutrino oscillation experiments.",
        "positive": "Studies on finite-volume effects in the inclusive semileptonic decays of\n  charmed mesons: We report on the calculation of the inclusive semileptonic decay of the $D_s$\nmeson on the lattice. We simulate the $D_s \\rightarrow X_s\\ell\\nu_\\ell$ process\nwith M\\\"obius domain-wall charm and strange quarks, whose masses were\napproximately tuned to the physical values. We cover the whole kinematical\nregion. The focus of this work is on the systematic error due to finite-volume\neffects. We construct a model of two-body final states to describe the data on\na finite volume lattice of $L \\simeq 0.055 \\, \\text{fm}$ to investigate the\nextrapolation to the infinite-volume limit."
    },
    {
        "anchor": "Evidence for the existence of $u d \\bar{b} \\bar{b}$ and the\n  non-existence of $s s \\bar{b} \\bar{b}$ and $c c \\bar{b} \\bar{b}$ tetraquarks\n  from lattice QCD: We combine lattice QCD results for the potential of two static antiquarks in\nthe presence of two quarks $q q$ of finite mass and quark model techniques to\nstudy possibly existing $q q \\bar{b} \\bar{b}$ tetraquarks. While there is\nstrong indication for a bound four-quark state for $q q = (ud-du) / \\sqrt{2}$,\ni.e. isospin $I=0$, we find clear evidence against the existence of\ncorresponding tetraquarks with $q q \\in \\{ uu , (ud+du) / \\sqrt{2} , dd \\}$,\ni.e. isospin $I=1$, $q q = s s$ and $q q = c c$.",
        "positive": "Non-perturbative states in the 3D phi^4 theory: We show that the spectrum of the three dimensional phi^4 theory in the broken\nsymmetry phase contains non-perturbative states. We determine the spectrum\nusing a new variational technique based on the introduction of operators\ncorresponding to different length scales. The presence of non-perturbative\nstates accounts for the discrepancy between Monte Carlo and perturbative\nresults for the universal ratio xi/xi_2nd. We introduce and study some\nuniversal amplitude ratios related to the overlap of the spin operator with the\nstates of the spectrum. The analysis is performed for the phi^4 theory\nregularized on a lattice and for the Ising model. This is a nice verification\nof the fact that universality reaches far beyond critical exponents. Finally,\nwe show that the spectrum of the model, including non-perturbative states,\naccurately matches the glueball spectrum in the Z(2) gauge model, which is\nrelated to the Ising model through a duality transformation."
    },
    {
        "anchor": "Two Geometric Approaches To Study The Deconfinement Phase Transition in\n  (3+1)-Dimensional $Z_2$ Gauge Theories: We have simulated $(3+1)-$dimensional finite temperature $Z_2$ gauge theory\nby using Metropolis algorithm. We aimed to observe the deconfinement phase\ntransitions by using geometric methods. In order to do so we have proposed two\ndifferent methods which can be applied to $3-$dimensional effective spin model\nconsisting of Polyakov loop variables. The first method is based on studies of\ncluster structures of each configuration. For each temperature, configurations\nare obtained from a set of bond probability ($P$) values. At a certain\nprobability, percolating clusters start to emerge. Unless the probability value\ncoincides with the Coniglio-Klein probability value, the fluctuations are less\nthan the actual fluctuations at the critical point. In this method the task is\nto identify the probability value which yields the highest peak in the\ndiverging quantities on finite lattices. The second method uses the scaling\nfunction based on the surface renormalization which is of geometric origin.\nSince this function is a scaling function, the measurements done on\ndifferent-size lattices yield the same value at the critical point, apart from\nthe correction to scaling terms. The linearization of the scaling function\naround the critical point yields the critical point and the critical exponents.",
        "positive": "QCD propagators and vertices from lattice QCD (in memory of Michael\n  M\u00fcller-Preu\u00dfker): We review lattice calculations of the elementary Greens functions of QCD with\na special emphasis on the Landau gauge. These lattice results have been of\ninterest to continuum approaches to QCD over the past 20 years. They are used\nas reference for Dyson-Schwinger- and functional renormalization group equation\ncalculations as well as for hadronic bound-state equations. The lattice\nprovides low-energy data for propagators and three-point vertices in Landau\ngauge at zero and finite temperature even including dynamical fermions. We\nsummarize Michael M\\\"uller-Preu{\\ss}ker's important contributions to this field\nand put them into the perspective of his other research interests."
    },
    {
        "anchor": "Complex Langevin boundary terms in lattice models: In complex Langevin simulations, the insufficient decay of the probability\ndensity near infinity leads to boundary terms that spoil the formal argument\nfor correctness. We present a formulation of this term that is cheaply\nmeasurable in lattice models, and in principle allows also the direct\nestimation of the systematic error of the CL method. Results for a toy model,\n3d XY model and HDQCD are presented.",
        "positive": "Lattice Landau gauge gluon propagator at finite temperature: non-zero\n  Matsubara frequencies and spectral densities: The lattice Landau gauge gluon propagator at finite temperature is computed\nincluding the non-zero Matsubara frequencies. Furthermore, the\nK\\\"all\\'en-Lehmann representation is inverted and the corresponding spectral\ndensity evaluated using a Tikhonov regularisation together with the Morozov\ndiscrepancy principle. Implications for gluon confinement are discussed."
    },
    {
        "anchor": "The PACS-CS Project: We describe our plan to develop a large-scale cluster system with a peak\nspeed of 14.3Tflops for lattice QCD at the Center for Computational Sciences,\nUniversity of Tsukuba, as a successor to the current 0.6Tflops CP-PACS\ncomputer. The system consist of 2560 nodes connected by a 16x16x10\nthree-dimensional hyper crossbar network. Each node has a single low-voltage\n2.8GHz Xeon processor and 2GBytes of memory with 6.4GBytes/sec bandwidth, and\n160 GBytes of disk in RAID1 mode. The network link in each of the three\ndirections is made of dual Gigabit Ethernet with the peak throughput of\n250MByte/sec. Hence each node has an aggregate network bandwidth of\n750MByte/sec. The system will run under Linux and SCore, and an extension of\nthe PM driver is developed for the network. The system will be developed\njointly with Hitachi Limited. The installation is scheduled in the first\nquarter of Japanese Fiscal 2006 (April-June 2006) and the start of operation is\nexpected in July 2006.",
        "positive": "Thermal QCD phase transition and its scaling window from Wilson twisted\n  mass fermions: We investigate the thermal QCD phase transition and its scaling properties on\nthe lattice. The simulations are performed with $N_f=2+1+1$ Wilson twisted mass\nfermions at pion masses from physical up to heavy quark regime. We introduce a\nnovel chiral order parameter, which is free from linear mass contributions and\nturns out to be very useful for the study of scaling behaviour. Our results are\ncompatible with $O(4)$ universal scaling for the physical pion mass and the\ntemperature range $[120:300]$ MeV. Violations to scaling at larger masses and\nother possible scenarios, including mean field behaviour and $Z(2)$ scaling\nscenario are also discussed. We provide an estimation for the critical\ntemperature in the chiral limit $T_0$."
    },
    {
        "anchor": "$f_B$ and $f_{B_s}$ using NRQCD: This talk summarizes the quenched calculation of $f_B$ and $f_{B_s}$\npresented in hep-lat/9801038. The heavy quark is simulated using an $O(1/M^2)$\nimproved NRQCD action, and the tadpole improved clover action is used for the\nlight quarks. The axial current includes the $O(1/M)$ corrections in one-loop\nperturbation theory and the $O(1/M^2)$ ones at tree-level. We discuss the\nvarious systematic effects and consistency checks made in the calculation.",
        "positive": "No strong coupling regime in the fermion-Higgs sector of the standard\n  model: We present results for the renormalized quartic self-coupling $\\lm_R$ and the\nrenormalized Yukawa coupling $y_R$ in a fermion-Higgs model with two SU(2)\ndoublets, indicating that these couplings are not very strong."
    },
    {
        "anchor": "Status of dynamical ensemble generation: I give an overview of current and future plans of dynamical QCD ensemble\ngeneration activities. A comparison of simulation cost between different\ndiscretizations is made. Recent developments in techniques and algorithms used\nin QCD dynamical simulations, especially mass reweighting, are also discussed.",
        "positive": "Study of 2+1 flavor finite-temperature QCD using improved Wilson quarks\n  at the physical point with the gradient flow: We study thermodynamic properties of 2+1 flavor QCD applying the Small\nFlow-time eXpansion (SFtX) method based on the gradient flow. The method\nprovides us with a general way to compute correctly renormalized observables\nirrespective of explicit violation of symmetries due to the regularization,\nsuch as the Poincare and chiral symmetries on the lattice. We report on the\nstatus of our on-going project to compute the energy-momentum tensor and the\nchiral condensate at the physical point with improved Wilson quarks, extending\nour previous study with slightly heavy u and d quarks. We also report on our\ntest of two-loop matching coefficients recently calculated by Harlander et al.,\nrevisiting the case of QCD with slightly heavy u and d quarks. Our results\nsuggest that the SFtX method is powerful in extracting physical observables on\nthe lattice."
    },
    {
        "anchor": "Lattice QCD Calculation of Hadron Scattering Lengths: Method of calculating hadron multi-point functions and disconnected quark\nloop contributions which are not readily accessible through conventional\ntechniques is proposed. Results are reported for pion-pion, pion-nucleon and\nnucleon-nucleon scattering lengths and the flavor singlet-non singlet meson\nmass splitting estimated in quenched QCD.",
        "positive": "Two Particle States in an Asymmetric Box and the Elastic Scattering\n  Phases: The exact two-particle energy eigenstates in a generic asymmetric rectangular\nbox with periodic boundary conditions in all three directions are studied.\nTheir relation with the elastic scattering phases of the two particles in the\ncontinuum are obtained for both $D_4$ and $D_2$ symmetry. These results can be\nviewed as a generalization of the corresponding formulae in a cubic box\nobtained by L\\\"uscher before. In particular, the s-wave scattering length is\nrelated to the energy shift in the finite box. Possible applications of these\nformulae are also discussed."
    },
    {
        "anchor": "Neutron electric dipole moment with external electric field method in\n  lattice QCD: We discuss a possibility that the Neutron Electric Dipole Moment (NEDM) can\nbe calculated in lattice QCD simulations in the presence of the CP violating\n$\\theta$ term. In this paper we measure the energy difference between spin-up\nand spin-down states of the neutron in the presence of an uniform and static\nexternal electric field. We first test this method in quenched QCD with the RG\nimproved gauge action on a $16^3\\times 32$ lattice at $a^{-1}\\simeq$ 2 GeV,\nemploying two different lattice fermion formulations, the domain-wall fermion\nand the clover fermion for quarks, at relatively heavy quark mass $(m_{PS}/m_V\n\\simeq 0.85)$. We obtain non-zero values of NEDM from calculations with both\nfermion formulations. We next consider some systematic uncertainties of our\nmethod for NEDM, using $24^3\\times 32$ lattice at the same lattice spacing only\nwith the clover fermion. We finally investigate the quark mass dependence of\nNEDM and observe a non-vanishing behavior of NEDM toward the chiral limit. We\ninterpret this behavior as a manifestation of the pathology in the quenched\napproximation.",
        "positive": "Form the density-of-states method to finite density quantum field theory: During the last 40 years, Monte Carlo calculations based upon Importance\nSampling have matured into the most widely employed method for determinig first\nprinciple results in QCD. Nevertheless, Importance Sampling leads to\nspectacular failures in situations in which certain rare configurations play a\nnon-secondary role as it is the case for Yang-Mills theories near a first order\nphase transition or quantum field theories at finite matter density when\nstudied with the re-weighting method. The density-of-states method in its LLR\nformulation has the potential to solve such overlap or sign problems by means\nof an exponential error suppression. We here introduce the LLR approach and its\ngeneralisation to complex action systems. Applications include U(1), SU(2) and\nSU(3) gauge theories as well as the Z3 spin model at finite densities and\nheavy-dense QCD."
    },
    {
        "anchor": "Universality of Pattern Formation: We study a $\\mathcal PT$-symmetric scalar Euclidean field theory with a\ncomplex action, using both theoretical analysis and lattice simulations. This\nmodel has a rich phase structure that exhibits pattern formation in the\ncritical region. Analytical results and simulations associate pattern formation\nwith tachyonic instabilities in the homogeneous phase. Monte Carlo simulation\nshows that pattern morphologies vary smoothly, without distinct microphases. We\nsuggest that pattern formation in this model may be regarded as a form of\narrested spinodal decomposition. We extend our theoretical analysis to\nmulticomponent $\\mathcal PT$-symmetric Euclidean scalar field theories and show\nthat they give rise to new universality classes of local field theories that\nexhibit patterned behavior in the critical region. QCD at finite temperature\nand density is a member of the $Z(2)$ universality class when the Polyakov loop\nis used to distinguish confined and deconfined phases. This suggests the\npossibility of the formation of patterns of confined and deconfined matter in\nQCD in the critical region in the $\\mu-T$ plane.",
        "positive": "A test of first order scaling in Nf=2 QCD: We complete our analysis of Nf=2 QCD based on the lattice staggered fermion\nformulation. Using a series of Monte Carlo simulations at fixed (amq*Ls^yh) one\nis able to test the universality class with given critical exponent yh. This\nstrategy has been used to test the O(4) universality class and it has been\npresented at the previous Lattice conferences. No agreement was found with\nsimulations in the mass range amq=[0.01335,0.15] using lattices with Ls=16 up\nto 32 and Lt=4. With the same strategy, we now investigate the possibility of a\nfirst order transition using a new set of Monte Carlo data corresponding to\nyh=3 in the same mass and volume range as the one used for O(4). A substantial\nagreement is observed both in the specific heat scaling and in the scaling of\nthe chiral condensate, while the chiral susceptibilities still presents visible\ndeviation from scaling in the mass range explored."
    },
    {
        "anchor": "Entanglement scaling for $\u03bb\u03c6_2^4$: We study the $\\lambda\\phi^4$ model in $0+2$ dimensions at criticality, and\neffectuate a simultaneous scaling of UV and IR physics. We demonstrate that the\norder parameter $\\phi$, the correlation length $\\xi$ and quantities like\n$\\phi^3$ and the entanglement entropy exhibit useful double scaling properties.\nThe calculations are performed with boundary matrix product state methods on\ntensor network representations of the partition function, though the technique\nis equally applicable outside the realm of tensor networks. We find the value\n$\\alpha_c=11.09698(31)$ for the critical point, improving on previous results.",
        "positive": "The Complex Langevin method: When can it be trusted?: We analyze to what extent the complex Langevin method, which is in principle\ncapable of solving the so-called sign problems, can be considered as reliable.\nWe give a formal derivation of the correctness and then point out various\nmathematical loopholes. The detailed study of some simple examples leads to\npractical suggestions about the application of the method."
    },
    {
        "anchor": "Comparing lattice Dirac operators with Random Matrix Theory: We study the eigenvalue spectrum of different lattice Dirac operators\n(staggered, fixed point, overlap) and discuss their dependence on the\ntopological sectors. Although the model is 2D (the Schwinger model with\nmassless fermions) our observations indicate possible problems in 4D\napplications. In particular misidentification of the smallest eigenvalues due\nto non-identification of the topological sector may hinder successful\ncomparison with Random Matrix Theory (RMT).",
        "positive": "Correlations in fluctuating geometries: We compare two definitions of connected correlation functions in fluctuating\ngeometries. We show results of the MC simulations for 4D dynamical\ntriangulation in the elongated phase and compare them with the exact\ncalculations of correlation functions in the branched polymer model."
    },
    {
        "anchor": "Two-flavor QCD simulation with exact chiral symmetry: We perform numerical simulations of lattice QCD with two flavors of dynamical\noverlap quarks, which have exact chiral symmetry on the lattice. While this\nfermion discretization is computationally demanding, we demonstrate the\nfeasibility to simulate reasonably large and fine lattices by a careful choice\nof the lattice action and algorithmic improvements. Our production runs are\ncarried out on a 16^3 \\times 32 lattice at a single lattice spacing around 0.12\nfm. We explore the sea quark mass region down to m_s/6, where m_s is the\nphysical strange quark mass, for a good control of the chiral extrapolation in\nfuture calculations of physical observables. We describe in detail our setup\nand algorithmic properties of the production simulations and present results\nfor the static quark potential to fix the lattice scale and the locality of the\noverlap operator.",
        "positive": "Confining strings in SU(N) gauge theories: We calculate the string tensions of $k$-strings in SU($N$) gauge theories in\nboth 3 and 4 dimensions. In D=3+1, we find that the ratio of the $k=2$ string\ntension to the $k = 1$ fundamental string tension is consistent, at the $2\n\\sigma$ level, with both the M(-theory)QCD-inspired conjecture and with\n`Casimir scaling'. In D=2+1 we see a definite deviation from the MQCD formula,\nas well as a much smaller but still significant deviation from Casimir scaling.\nWe find that in both D=2+1 and D=3+1 the high temperature spatial $k$-string\ntensions also satisfy approximate Casimir scaling. We point out that\napproximate Casimir scaling arises naturally if the cross-section of the flux\ntube is nearly independent of the flux carried, and that this will occur in an\neffective dual superconducting description, if we are in the deep-London limit.\nWe estimate, numerically, the intrinsic width of $k$-strings in D=2+1 and\nindeed find little variation with $k$. In addition to the stable $k$-strings we\ninvestigate some ofthe unstable strings, finding in D=2+1 that they satisfy\n(approximate) Casimir scaling. We also investigate the basic assumption that\nconfining flux tubes are described by an effective string theory at large\ndistances. We estimate the coefficient of the universal L\\\"uscher correction\nfrom periodic strings that are longer than 1 fermi, and find $c_L=0.98(4)$ in\nD=3+1 and $c_L=0.558(19)$ in D=2+1. These values are within $2 \\sigma$ of the\nsimple bosonic string values and are inconsistent with other simple effective\nstring theories."
    },
    {
        "anchor": "String Breaking in Quenched QCD: We present preliminary quenched results on a new operator for the\ninvestigation of string-breaking within SU(2)-colour QCD. The ground-state of a\nspatially-separated static-light meson-antimeson pair is a combination of a\nstate with two distinct mesons, expected to dominate for large separations, and\na state where the light-quarks have annihilated, which contributes for short\ndistances. The crossover between these two regimes provides a measure of the\nstring-breaking scale length.",
        "positive": "Status report on $\\varepsilon_K$ with lattice QCD inputs: We report the current status of $\\varepsilon_K$, the indirect CP violation\nparameter in the neutral kaon system, evaluated using the lattice QCD inputs.\nWe use lattice QCD to fix $\\hat{B}_K$, $\\xi_0$, $\\xi_2$, $|V_{us}|$,\n$m_c(m_c)$, and $|V_{cb}|$. Since Lattice 2015, FLAG updated $\\hat{B}_K$,\nexclusive $V_{cb}$ has been updated with new lattice data in the $\\bar{B}\\to\nD\\ell\\nu$ decay channel, and RBC-UKQCD has updated $\\xi_0$ and $\\xi_2$. Our\npreliminary results show that the standard model evaluation of $\\varepsilon_K$\nwith exclusive $|V_{cb}|$ (lattice QCD inputs) has $3.2\\sigma$ tension with the\nexperimental value, while that of $\\varepsilon_K$ with inclusive $|V_{cb}|$\n(heavy quark expansion) shows no tension."
    },
    {
        "anchor": "Topological susceptibility from twisted mass fermions using spectral\n  projectors and the gradient flow: We compare lattice QCD determinations of topological susceptibility using a\ngluonic definition from the gradient flow and a fermionic definition from the\nspectral projector method. We use ensembles with dynamical light, strange and\ncharm flavors of maximally twisted mass fermions. For both definitions of the\nsusceptibility we employ ensembles at three values of the lattice spacing and\nseveral quark masses at each spacing. The data are fitted to chiral\nperturbation theory predictions with a discretization term to determine the\ncontinuum chiral condensate in the massless limit and estimate the overall\ndiscretization errors. We find that both approaches lead to compatible results\nin the continuum limit, but the gluonic ones are much more affected by cut-off\neffects. This finally yields a much smaller total error in the spectral\nprojector results. We show that there exists, in principle, a value of the\nspectral cutoff which would completely eliminate discretization effects in the\ntopological susceptibility.",
        "positive": "An Introduction to Chiral Symmetry on the Lattice: The $SU(N_f)_L \\otimes SU(N_f)_R$ chiral symmetry of QCD is of central\nimportance for the nonperturbative low-energy dynamics of light quarks and\ngluons. Lattice field theory provides a theoretical framework in which these\ndynamics can be studied from first principles. The implementation of chiral\nsymmetry on the lattice is a nontrivial issue. In particular, local lattice\nfermion actions with the chiral symmetry of the continuum theory suffer from\nthe fermion doubling problem. The Ginsparg-Wilson relation implies L\\\"uscher's\nlattice variant of chiral symmetry which agrees with the usual one in the\ncontinuum limit. Local lattice fermion actions that obey the Ginsparg-Wilson\nrelation have an exact chiral symmetry, the correct axial anomaly, they obey a\nlattice version of the Atiyah-Singer index theorem, and still they do not\nsuffer from the notorious doubling problem. The Ginsparg-Wilson relation is\nsatisfied exactly by Neuberger's overlap fermions which are a limit of Kaplan's\ndomain wall fermions, as well as by Hasenfratz and Niedermayer's classically\nperfect lattice fermion actions. When chiral symmetry is nonlinearly realized\nin effective field theories on the lattice, the doubling problem again does not\narise. This review provides an introduction to chiral symmetry on the lattice\nwith an emphasis on the basic theoretical framework."
    },
    {
        "anchor": "High-precision computation of two-loop Feynman diagrams with Wilson\n  fermions: We apply the coordinate-space method by Luescher and Weisz to the computation\nof two-loop diagrams in full QCD with Wilson fermions on the lattice. The\nessential ingredient is the high-precision determination of mixed\nfermionic-bosonic propagators.",
        "positive": "Lattice regularization of chiral gauge theories to all orders of\n  perturbation theory: In the framework of perturbation theory, it is possible to put chiral gauge\ntheories on the lattice without violating the gauge symmetry or other\nfundamental principles, provided the fermion representation of the gauge group\nis anomaly-free. The basic elements of this construction (which starts from the\nGinsparg-Wilson relation) are briefly recalled and the exact cancellation of\nthe gauge anomaly, at any fixed value of the lattice spacing and for any\ncompact gauge group, is then proved rigorously through a recursive procedure."
    },
    {
        "anchor": "Localization in Lattice Gauge Theory and a New Multigrid Method: We show numerically that the lowest eigenmodes of the 2-dimensional\nLaplace-operator with SU(2) gauge couplings are strongly localized. A\nconnection is drawn to the Anderson-Localization problem. A new Multigrid\nalgorithm, capable to deal with these modes, shows no critical slowing down for\nthis problem.",
        "positive": "Quark and Gluon Propagators in Covariant Gauges: We present data for the gluon and quark propagators computed in the standard\nlattice Landau's gauge and for three values of the covariant gauge-fixing\nparameter lambda=0,8,16. Our results are obtained using the SU(3) Wilson action\nin the quenched approximation at beta=6.0 and volume=16^3x32."
    },
    {
        "anchor": "Centre Vortex Effects on the Overlap Quark Propagator: We investigate the role of centre vortices in dynamical mass generation using\noverlap fermions. The exact chiral symmetry that the overlap fermion action\npossesses yields a distinctive response to the underlying topology of the gauge\nfield, leading to novel results. We study the quark propagator and associated\nmass function on gauge field backgrounds featuring the removal of centre\nvortices as well as on vortex-only backgrounds. The effect of cooling\nvortex-only backgrounds on the overlap quark propagator is also presented.",
        "positive": "Unquenched Charmonium with NRQCD - Lattice 2000: We present results from a series of NRQCD simulations of the charmonium\nsystem, both in the quenched approximation and with n_f = 2 dynamical quarks.\nThe spectra show evidence for quenching effects of ~10% in the S- and\nP-hyperfine splittings. We compare this with other systematic effects.\nImproving the NRQCD evolution equation altered the S-hyperfine by as much as 20\nMeV, and we estimate radiative corrections may be as large as 40%."
    },
    {
        "anchor": "Qubit regularization of asymptotic freedom: We provide strong evidence that the asymptotically free (1+1)-dimensional\nnon-linear O(3) sigma model can be regularized using a quantum lattice\nHamiltonian, referred to as the \"Heisenberg-comb\", that acts on a Hilbert space\nwith only two qubits per spatial lattice site. The Heisenberg-comb consists of\na spin-half anti-ferromagnetic Heisenberg-chain coupled anti-ferromagnetically\nto a second local spin-half particle at every lattice site. Using a world-line\nMonte Carlo method we show that the model reproduces the universal step-scaling\nfunction of the traditional model up to correlation lengths of 200,000 in\nlattice units and argue how the continuum limit could emerge. We provide a\nquantum circuit description of time-evolution of the model and argue that\nnear-term quantum computers may suffice to demonstrate asymptotic freedom.",
        "positive": "Properties of the Z(3) Interface in (2+1)-D SU(3) Gauge Theory: A study is made of some properties of this interface in the SU(3) pure gauge\ntheory in 2+1 dimensions. At high temperatures, the interface tension is\nmeasured and shows agreement with the perturbative prediction. Near the\ncritical temperature, the behaviour of the interface is examined, and its\nfluctuations compared to a scalar field theory model."
    },
    {
        "anchor": "Chiral Behaviour of the Rho Meson in Lattice QCD: In order to guide the extrapolation of the mass of the rho meson calculated\nin lattice QCD with dynamical fermions, we study the contributions to its\nself-energy which vary most rapidly as the quark mass approaches zero; from the\nprocesses $\\rho \\to \\omega \\pi$ and $\\rho \\to \\pi \\pi$. It turns out that in\nanalysing the most recent data from CP-PACS it is crucial to estimate the\nself-energy from $\\rho \\to \\pi \\pi$ using the same grid of discrete momenta as\nincluded implicitly in the lattice simulation. The correction associated with\nthe continuum, infinite volume limit can then be found by calculating the\ncorresponding integrals exactly. Our error analysis suggests that a factor of\n10 improvement in statistics at the lowest quark mass for which data currently\nexists would allow one to determine the physical rho mass to within 5%.\nFinally, our analysis throws new light on a long-standing problem with the\nJ-parameter.",
        "positive": "Analytic continuation in two-color QCD: new results on the critical line: We test the method of analytic continuation from imaginary to real chemical\npotential in two-color QCD, which is free from the sign problem. In particular,\nwe consider the analytic continuation of the critical line to real values of\nthe chemical potential."
    },
    {
        "anchor": "Thermal dynamics on the lattice with exponentially improved accuracy: We present a novel simulation prescription for thermal quantum fields on a\nlattice that operates directly in imaginary frequency space. By distinguishing\ninitial conditions from quantum dynamics it provides access to correlation\nfunctions also outside of the conventional Matsubara frequencies $\\omega_n=2\\pi\nn T$. In particular it resolves their frequency dependence between $\\omega=0$\nand $\\omega_1=2\\pi T$, where the thermal physics $\\omega\\sim T$ of\ne.g.~transport phenomena is dominantly encoded. Real-time spectral functions\nare related to these correlators via an integral transform with rational\nkernel, so their unfolding is exponentially improved compared to Euclidean\nsimulations. We demonstrate this improvement within a $0+1$-dimensional scalar\nfield theory and show that spectral features inaccessible in standard Euclidean\nsimulations are quantitatively captured.",
        "positive": "Are Topological Charge Fluctuations in QCD Instanton Dominated?: We consider a recent proposal by Horv\\'ath {\\em et al.} to address the\nquestion whether topological charge fluctuations in QCD are instanton dominated\nvia the response of fermions using lattice fermions with exact chiral symmetry,\nthe overlap fermions. Considering several volumes and lattice spacings we find\nstrong evidence for chirality of a finite density of low-lying eigenvectors of\nthe overlap-Dirac operator in the regions where these modes are peaked. This\nresult suggests instanton dominance of topological charge fluctuations in\nquenched QCD."
    },
    {
        "anchor": "Full QCD with dynamical Wilson fermions on a 24^3 x 40-lattice -- a\n  feasibility study: The investigation of light sea-quark effects in lattice QCD with dynamical\nWilson fermions requires both larger physical volumes and finer lattice\nresolutions than achieved previously. As high-end supercomputers like the\n512-node APE Tower provide the compute power to perform a major step towards\nthe chiral limit (T-chi-L), we have launched a feasibility study on a 24^3 x 40\nlattice. We approach the chiral limit--while refining the resolution--, using\nthe standard Wilson fermion action. Following previous work, our Hybrid Monte\nCarlo simulation runs at beta=5.6 and two kappa-values, 0.1575 and 0.158. From\nour study, we are confident that, for the APE Tower, a realistic working point\nhas been found corresponding to a volume of 2 fm^3, with chirality\ncharacterized by 1/(a m_pi) = 5.6.",
        "positive": "On the Dynamics of Light Wilson Quarks: We describe recent results obtained as part of the High Energy Monte Carlo\nGrand Challenge (HEMCGC) project concerning the behaviour of lattice QCD with\nlight dynamical Wilson quarks. We show that it is possible to reach regions of\nparameter space with light pions $m_\\pi\\ll0.2/a$, but that the equilibration\ntime for such a system is at least of the order of 1,000 unit-length Hybrid\nMonte Carlo (HMC) trajectories (about a Gigaflop/sec-year). If the Hybrid\nMolecular Dynamics (HMD) algorithm is used with the same parameters it gives\nincorrect results."
    },
    {
        "anchor": "Scaling Study of the Leptonic Decay Constants of Heavy-Light Mesons: A\n  Consumers Report on Improvement Factors: A high statistics calculation, performed at $\\beta =5.74,\\;6.00$ and $6.26$,\nenables us to study the variation of the leptonic decay constants $f_P$ of\nheavy pseudoscalar mesons with the lattice spacing $a$. We observe only a weak\n$a$ dependence when the standard $\\sqrt{2\\kappa}$ normalization is used for the\nquark fields, whereas application of the Kronfeld-Mackenzie normalization\ninduces a stronger variation with $a$. Increasing the meson mass from $1.1GeV$\nto $2.3GeV$ this situation becomes even more pronounced.",
        "positive": "Luescher-Weisz algorithm for excited states of the QCD flux-tube: We present a version of the Luescher-Weisz multilevel algorithm ideally\nsuited for studying excited states of the QCD flux tube. While the original\nversion achieved error reduction only in the temporal direction, the new\nalgorithm reduces fluctuations in the sources as well. We report on the\nimplementation of this algorithm as well as improvement over the older method.\nWe also present first results, where we see a good agreement with theoretical\npredictions from bosonic string models."
    },
    {
        "anchor": "High temperature quark localization by Polyakov loops: We study the low eigenmodes of the overlap and staggered Dirac operator at\nhigh temperature. We show that the recently found localized quark modes obeying\nPoisson statistics are connected to physical gauge field objects with their\nsize and density scaling in the continuum limit. The localized modes are also\nstrongly correlated with large fluctuations of the Polyakov loop. Based on that\nwe construct a random matrix model of the low Dirac modes inspired by\ndimensional reduction. Our model reproduces the Poisson to random matrix\ntransition seen in the lattice Dirac spectrum.",
        "positive": "Non-perturbative renormalization for a renormalization group improved\n  gauge action: Renormalization constants of vector ($Z_V$) and axial-vector ($Z_A$) currents\nare determined non-perturbatively in quenched QCD for a renormalization group\nimproved gauge action and a tadpole improved clover quark action using the\nSchr\\\"odinger functional method. Non-perturbative values of $Z_V$ and $Z_A$\nturn out to be smaller than the one-loop perturbative values by $O(10%)$ at\n$a^{-1}\\approx 1$ GeV. A sizable scaling violation of meson decay constants\n$f_\\pi$ and $f_\\rho$ observed with the one-loop renormalization factors remains\neven with non-perturbative renormalization."
    },
    {
        "anchor": "The hadron spectrum from twisted mass QCD with a strange quark: Various suggestions exist for incorporating the strange quark into twisted\nmass QCD. One option for quenched simulations is to employ two twisted\ndoublets, (u,d) and (c,s), with separate twist angles. Working in the isospin\nlimit, preliminary results for the quenched spectrum of strange hadrons are\npresented, with both twist angles tuned to pi/2. Splittings within the mass\nmultiplets provide some insight into the symmetry breaking effects of twisted\nmass lattice QCD.",
        "positive": "Lattice QCD Calculation of Nuclear Parity Violation: We present the first lattice QCD calculation of the leading-order\nmomentum-independent parity violating coupling between pions and nucleons,\n$h_{\\pi{NN}}^1$. The calculation performs measurements on dynamical anisotropic\nclover gauge configurations, with a spatial extent of $L\\sim2.5$ fm, a spatial\nlattice spacing of $a_s\\sim0.123$ fm, and a pion mass of $m_{\\pi}\\sim389$ MeV.\nWhile this first calculation does not include non-perturbative renormalization\nof the bare parity-violating operators, a chiral extrapolation to the physical\npion mass, or contributions from disconnected (quark-loop) diagrams, these are\nexpected to result in systematic errors within the quoted statistical error. We\nfind a contribution from the `connected' diagrams of\n$h_{\\pi{NN}}^{1,con}=(1.099\\pm0.505^{+0.058}_{-0.064})\\times10^{-7}$,\nconsistent with current experimental bounds and previous model-dependent\ntheoretical predictions."
    },
    {
        "anchor": "Efficient computation of baryon interpolating fields in Lattice QCD: In this work we present an efficient construction of baryon interpolating\nfields for lattice QCD computations of two and three point functions. These are\nessential building blocks of computations of nucleon parton distribution\nfunctions (PDFs), generalized parton distribution functions (GPDs) and\ntransverse momentum dependent distributions functions (TMDs). Lattice QCD\ncomputations of these quantities can provide additional input to assist with\nthe global fits on experimental data for determining TMDs, GPDs and PDFs.",
        "positive": "Light hadron spectroscopy in two-flavor QCD with small sea quark masses: We extend the study of the light hadron spectrum and the quark mass in\ntwo-flavor QCD to smaller sea quark mass, corresponding to\n$m_{PS}/m_{V}=0.60$--0.35. Numerical simulations are carried out using the\nRG-improved gauge action and the meanfield-improved clover quark action at\n$\\beta=1.8$ ($a = 0.2$ fm from $\\rho$ meson mass). We observe that the light\nhadron spectrum for small sea quark mass does not follow the expectation from\nchiral extrapolations with quadratic functions made from the region of\n$m_{PS}/m_{V}=0.80$--0.55. Whereas fits with either polynomial or continuum\nchiral perturbation theory (ChPT) fails, the Wilson ChPT (WChPT) that includes\n$a^2$ effects associated with explicit chiral symmetry breaking successfully\nfits the whole data: In particular, WChPT correctly predicts the light quark\nmass spectrum from simulations for medium heavy quark mass, such as $m_{PS}/m_V\n\\simgt 0.5$. Reanalyzing the previous data %at $m_{PS}/m_{V}=0.80$--0.55 with\nthe use of WChPT, we find the mean up and down quark mass being smaller than\nthe previous result from quadratic chiral extrapolation by approximately 10%,\n$m_{ud}^{\\bar{\\rm MS}}(\\mu=2 {GeV}) = 3.11(17)$ [MeV] in the continuum limit."
    },
    {
        "anchor": "BK from the lattice with Wilson quarks: We report our results for the bag-parameter BK obtained from the quenched\nsimulations on the lattice with Wilson fermions at three values of the lattice\nspacing. We implemented the method by which no subtraction of the mixing with\nother four-fermion dS=2 operators is needed. Our final result, in terms of the\nrenormalisation group invariant bag-parameter, is BK = 0.96 +/- 0.10.",
        "positive": "On two- and three-point functions of Landau gauge Yang-Mills theory: We present results for the gluon and ghost propagators and the ghost-gluon\nvertex obtained from Dyson-Schwinger equations. In the zero temperature case we\nelaborate on the role of the three-gluon vertex and discuss a model that can\ncapture its qualitative features like its anomalous dimensions and a zero\ncrossing of the dressing function. Our results compare well with lattice data.\nAt non-zero temperature we calculated the ghost propagator which agrees rather\nwell with lattice results already within our simple truncation. These results\nare used to obtain the temperature dependence of the ghost-gluon vertex. We\nalso explain why the ghost propagator does not react to the phase transition\ndespite its direct coupling to the chromoelectric gluon."
    },
    {
        "anchor": "How to approach continuum physics in lattice Weinberg - Salam model: We investigate lattice Weinberg - Salam model without fermions numerically\nfor the realistic choice of coupling constants correspondent to the value of\nthe Weinberg angle $\\theta_W \\sim 30^o$, and bare fine structure constant\naround $\\alpha \\sim 1/150$. We consider the values of the scalar self coupling\ncorresponding to Higgs mass $M_H \\sim 100, 150, 270$ GeV. It has been found\nthat nonperturbative effects become important while approaching continuum\nphysics within the lattice model. When the ultraviolet cutoff $\\Lambda =\n\\frac{\\pi}{a}$ (where $a$ is the lattice spacing) is increased and achieves the\nvalue around 1 TeV one encounters the fluctuational region (on the phase\ndiagram of the lattice model), where the fluctuations of the scalar field\nbecome strong. The classical Nambu monopole can be considered as an embryo of\nthe unphysical symmetric phase within the physical phase. In the fluctuational\nregion quantum Nambu monopoles are dense and, therefore, the use of the\nperturbation expansion around trivial vacuum in this region is limited. Further\nincrease of the cutoff is accompanied by a transition to the region of the\nphase diagram, where the scalar field is not condensed (this happens at the\nvalue of $\\Lambda$ around 1.4 TeV for the considered lattice sizes). Within\nthis region further increase of the cutoff is possible although we do not\nobserve this in details due to the strong fluctuations of the gauge boson\ncorrelator. Both mentioned above regions look unphysical. Therefore we come to\nthe conclusion that the maximal value of the cutoff admitted within lattice\nElectroweak theory cannot exceed the value of the order of 1 TeV.",
        "positive": "The Sphaleron Rate from 4D Euclidean Lattices: We develop a new method to determine thermal activation rates, such as for\nbubble nucleation, topology change, \\textsl{etc.}, using 4-dimensional\nEuclidean methods. This allows nonperturbative study on the lattice. We then\ninvestigate the strong sphaleron rate in pure-glue QCD at temperatures between\n1.3 $\\Tc$ and 1000 $T_\\mathrm{c}$, making contact with previous results but\nextending them down close to the critical temperature. The extension to full\nQCD will be straightforward. Limitations of the proposal (the inability to\ncompute a certain dynamical prefactor, puzzling large-volume behavior, and the\ninability to treat temperatures $T < 1.3 \\, T_\\mathrm{c}$) are also discussed."
    },
    {
        "anchor": "Ground state charmed meson spectra for N_f=2+1+1: We present a preliminary study of the charmed meson spectra using the\nelectrically neutral subset of the new Budapest-Marseille-Wuppertal N_f=2+1+1\ngauge configurations that utilise the 3-HEX smeared clover action. The analysis\nis performed with a focus on the hyperfine splitting.",
        "positive": "Lattice QCD calculation of the two-photon exchange contribution to the\n  muonic-hydrogen Lamb shift: We develop a method for lattice QCD calculation of the two-photon exchange\ncontribution to the muonic-hydrogen Lamb shift. To demonstrate its feasibility,\nwe present the first lattice calculation with a gauge ensemble at $m_\\pi = 142$\nMeV. By adopting the infinite-volume reconstruction method along with an\noptimized subtraction scheme, we obtain $\\Delta E_{\\text{TPE}} =\n-28.9(4.9)~\\mu\\text{eV} + 93.72~\\mu\\text{eV}/\\text{fm}^2 \\cdot\\langle r_p^2\n\\rangle$, or $\\Delta E_{\\text{TPE}} = 37.4(4.9)~\\mu$eV, which is consistent\nwith the previous theoretical results in a range of 20-50 $\\mu$eV."
    },
    {
        "anchor": "Finite size scaling study of $N_{\\text{f}}=4$ finite density QCD on the\n  lattice: We explore the phase space spanned by the temperature and the chemical\npotential for 4-flavor lattice QCD using the Wilson-clover quark action. In\norder to determine the order of the phase transition, we apply finite size\nscaling analyses to gluonic and quark observables including plaquette, Polyakov\nloop and quark number density, and examine their susceptibility, skewness,\nkurtosis and Challa-Landau-Binder cumulant. Simulations were carried out on\nlattices of a temporal size fixed at $N_{\\text{t}}=4$ and spatial sizes chosen\nfrom $6^3$ up to $10^3$. Configurations were generated using the phase\nreweighting approach, while the value of the phase of the quark determinant\nwere carefully monitored. The $\\mu$-parameter reweighting technique is employed\nto precisely locate the point of the phase transition. Among various\napproximation schemes for calculating the ratio of quark determinants needed\nfor $\\mu$-reweighting, we found the Taylor expansion of the logarithm of the\nquark determinant to be the most reliable. Our finite-size analyses show that\nthe transition is first order at $(\\beta, \\kappa, \\mu/T)=(1.58, 0.1385,\n0.584\\pm 0.008)$ where $(m_\\pi/m_\\rho, T/m_\\rho)=(0.822, 0.154)$. It weakens\nconsiderably at $(\\beta, \\kappa, \\mu/T)=(1.60, 0.1371, 0.821\\pm 0.008)$ where\n$(m_\\pi/m_\\rho, T/m_\\rho)=(0.839, 0.150)$, and a crossover rather than a first\norder phase transition cannot be ruled out.",
        "positive": "Static quark anti-quark pair in SU(2) gauge theory: We study singlet and triplet correlation functions of static quark anti-quark\npair defined through gauge invariant time-like Wilson loops and Polyakov loop\ncorrelators in finite temperature SU(2) gauge theory. We use the Luescher-Weisz\nmultilevel algorithm, which allows to calculate these correlators at very low\ntemperatures. We observe that the naive separation of singlet and triplet\nstates in general does not hold non-perturbatively, however, is recovered in\nthe limit of small separation and the temperature dependence of the\ncorresponding correlators is indeed very different."
    },
    {
        "anchor": "Anomaly cancellation for anisotropic lattice fields with extra\n  dimensions: The current flow from the bulk is due to the anomaly on the brane-but the\nabsence of current flow is not, necessarily, due to anomaly cancellation, but\nto the absence of the chiral zero modes themselves, due to the existence of the\nlayered phase. This can be understood in terms of the difference between the\nChern-Simons terms in three and five dimensions. Thus the anomaly cancellation\nin four dimensions, which is essential for shielding the boundary from quantum\neffects within the bulk, makes sense only along the transition line between the\nlayered and the Coulomb phase, which, in turn, requires the presence of a\ncompact U(1) factor for the gauge group.",
        "positive": "Lattice QCD at the physical point: Simulation and analysis details: We give details of our precise determination of the light quark masses\nm_{ud}=(m_u+m_d)/2 and m_s in 2+1 flavor QCD, with simulated pion masses down\nto 120 MeV, at five lattice spacings, and in large volumes. The details concern\nthe action and algorithm employed, the HMC force with HEX smeared clover\nfermions, the choice of the scale setting procedure and of the input masses.\nAfter an overview of the simulation parameters, extensive checks of algorithmic\nstability, autocorrelation and (practical) ergodicity are reported. To\ncorroborate the good scaling properties of our action, explicit tests of the\nscaling of hadron masses in N_f=3 QCD are carried out. Details of how we\ncontrol finite volume effects through dedicated finite volume scaling runs are\nreported. To check consistency with SU(2) Chiral Perturbation Theory the\nbehavior of M_\\pi^2/m_{ud} and F_\\pi as a function of m_{ud} is investigated.\nDetails of how we use the RI/MOM procedure with a separate continuum limit of\nthe running of the scalar density R_S(\\mu,\\mu') are given. This procedure is\nshown to reproduce the known value of r_0m_s in quenched QCD. Input from\ndispersion theory is used to split our value of m_{ud} into separate values of\nm_u and m_d. Finally, our procedure to quantify both systematic and statistical\nuncertainties is discussed."
    },
    {
        "anchor": "Complete spectra of the Dirac operator and their relation to confinement: We compute complete spectra of the staggered lattice Dirac operator for\nquenched SU(3) gauge configurations below and above the critical temperature.\nThe confined and the deconfined phase are characterized by a different response\nof the Dirac eigenvalues to a change of the fermionic boundary conditions. We\nanalyze the role of the eigenvalues in recently developed spectral sums\nrepresenting the Polyakov loop. We show that the Polyakov loop gets its main\ncontributions from the UV end of the spectrum.",
        "positive": "Super-Instantons in Gauge Theories and Troubles with Perturbation Theory: In gauge theories with continuous groups there exist classical solutions\nwhose energy vanishes in the thermodynamic limit (in any dimension). The\nexistence of these super-instantons is intimately related to the fact that even\nat short distances perturbation theory can fail to produce unique results. This\nproblem arises only in non-Abelian models and only starting at O(1/beta^2)."
    },
    {
        "anchor": "Twisted mass gauge ensembles at physical values of the light, strange\n  and charm quark masses: Lattice QCD simulations directly at physical masses of dynamical light,\nstrange and charm quarks are highly desirable especially to remove systematic\nerrors due to chiral extrapolations. However such simulations are still\nchallenging. We discuss the adaption of efficient algorithms, like multi-grid\nmethods or higher order integrators, within the molecular dynamic steps of the\nHybrid Monte Carlo algorithm, that are enabling simulations of a new set of\ngauge ensembles by the Extended Twisted Mass collaboration (ETMC). We present\nthe status of the on-going ETMC simulation effort that aims to enabling studies\nof finite size and discretization effects. We work within the twisted mass\ndiscretization which is free of odd-discretization effects at maximal twist and\npresent our tuning procedure.",
        "positive": "Scaling functions of the three-dimensional $Z(2)$, $O(2)$ and $O(4)$\n  models and their finite size dependence in an external field: We analyze scaling functions in the $3$-$d$, $Z(2)$, $O(2)$ and $O(4)$\nuniversality classes and their finite size dependence using Monte Carlo\nsimulations of improved $\\phi^4$ models. Results for the scaling functions are\nfitted to the Widom-Griffiths form, using a parametrization also used in\nanalytic calculations. We find good agreement on the level of scaling functions\nand the location of maxima in the universal part of susceptibilities. We also\nfind that an earlier parametrization of the $O(4)$ scaling function, using 14\nparameters, is well reproduced when using the Widom-Griffiths form with only\nthree parameters. We furthermore show that finite size corrections to the\nscaling functions are distinctively different in the $Z(2)$ and $O(N)$\nuniversality classes and determine the volume dependence of the peak locations\nin order parameter and mixed susceptibilities."
    },
    {
        "anchor": "ISU - Multigrid for computing propagators: The Iteratively Smoothing Unigrid algorithm (ISU), a new multigrid method for\ncomputing propagators in Lattice Gauge Theory, is explained. The main idea is\nto compute good (i.e.\\ smooth) interpolation operators in an iterative way.\nThis method shows {\\em no critical slowing down} for the 2-dimensional Laplace\nequation in an SU(2) gauge field. First results for the Dirac-operator are also\nshown.",
        "positive": "Chiral Random Matrix Model at Finite Chemical Potential: Characteristic\n  Determinant and Edge Universality: We derive an exact formula for the stochastic evolution of the characteristic\ndeterminant of a class of deformed Wishart matrices following from a chiral\nrandom matrix model of QCD at finite chemical potential. In the WKB\napproximation, the characteristic determinant describes a sharp droplet of\neigenvalues that deforms and expands at large stochastic times. Beyond the WKB\nlimit, the edges of the droplet are fuzzy and described by universal edge\nfunctions. At the chiral point, the characteristic determinant in the\nmicroscopic limit is universal. Remarkably, the physical chiral condensate at\nfinite chemical potential may be extracted from current and quenched lattice\nDirac spectra using the universal edge scaling laws, without having to solve\nthe QCD sign problem."
    },
    {
        "anchor": "Wave functions of the nucleon and its parity partner from lattice QCD: We compute moments of distribution amplitudes using gauge configurations with\ntwo flavors of clover fermions from QCDSF/DIK and operators which are optimized\nwith respect to their behavior under the lattice symmetries. The knowledge of\nthese quantities helps in understanding the internal structure of hadrons and\nin the analysis of (semi-)exclusive processes. We present results for the\nnucleon distribution amplitude which suggest that the asymmetries (the\ndeviations from the asymptotic form) are smaller than indicated by sum rule\ncalculations. Using the same approach we were also able to calculate the same\nquantities for the $N^\\star(1535)$, the parity partner of the nucleon. These\nresults show a stronger deviation from the asymptotic form.",
        "positive": "Locally smeared operator product expansions in scalar field theory: We propose a new locally smeared operator product expansion to decompose\nnonlocal operators in terms of a basis of smeared operators. The smeared\noperator product expansion formally connects nonperturbative matrix elements\ndetermined numerically using lattice field theory to matrix elements of\nnonlocal operators in the continuum. These nonperturbative matrix elements do\nnot suffer from power-divergent mixing on the lattice, which significantly\ncomplicates calculations of quantities such as the moments of parton\ndistribution functions, provided the smearing scale is kept fixed in the\ncontinuum limit. The presence of this smearing scale complicates the connection\nto the Wilson coefficients of the standard operator product expansion and\nrequires the construction of a suitable formalism. We demonstrate the\nfeasibility of our approach with examples in real scalar field theory."
    },
    {
        "anchor": "Flavor extrapolations and staggered fermions: A popular approximation in lattice gauge theory is an extrapolation in the\nnumber of fermion species away from the four fold degeneracy natural with the\nstaggered fermions formulation. I show that at finite lattice spacing and for\nan odd number of flavors this extrapolation misses terms which, on general\nprinciples, must be present in the continuum theory. For a correct continuum\nlimit, this forces unphysical singularities in parameter regions where\ncontinuum physics is smooth and all physical particles are massive. These\nsingularities are not expected with other lattice regulators. Finally, I argue\nthat unnatural constraints on certain correlation functions appear even when\nall quarks are massive.",
        "positive": "Continuum extrapolation of the gradient-flowed color-magnetic correlator\n  at $1.5\\,T_c$: In a recently published work we employ gradient flow on the lattice to\nextract the leading contribution of the heavy quark momentum diffusion\ncoefficient in the heavy quark limit from calculations of a well-known\ntwo-point function of color-electric field operators. In this article we want\nto report the progress of calculating the recently derived color-magnetic\ncorrelator that encodes a finite mass correction to this transport coefficient.\nThe calculations we present here are based on the same ensemble of quenched\ngauge configurations at $1.5\\, T_c$ that we previously used for the\ncolor-electric correlator."
    },
    {
        "anchor": "Perturbative expansions from Monte Carlo simulations at weak coupling:\n  Wilson loops and the static-quark self-energy: Perturbative coefficients for Wilson loops and the static-quark self-energy\nare extracted from Monte Carlo simulations at weak coupling. The lattice\nvolumes and couplings are chosen to ensure that the lattice momenta are all\nperturbative. Twisted boundary conditions are used to eliminate the effects of\nlattice zero modes and to suppress nonperturbative finite-volume effects due to\nZ(3) phases. Simulations of the Wilson gluon action are done with both periodic\nand twisted boundary conditions, and over a wide range of lattice volumes (from\n$3^4$ to $16^4$) and couplings (from $\\beta \\approx 9$ to $\\beta \\approx 60$).\nA high precision comparison is made between the simulation data and results\nfrom finite-volume lattice perturbation theory. The Monte Carlo results are\nshown to be in excellent agreement with perturbation theory through second\norder. New results for third-order coefficients for a number of Wilson loops\nand the static-quark self-energy are reported.",
        "positive": "Supersymmetric quantum mechanics on the lattice: III. Simulations and\n  algorithms: In the fermion loop formulation the contributions to the partition function\nnaturally separate into topological equivalence classes with a definite sign.\nThis separation forms the basis for an efficient fermion simulation algorithm\nusing a fluctuating open fermion string. It guarantees sufficient tunnelling\nbetween the topological sectors, and hence provides a solution to the fermion\nsign problem affecting systems with broken supersymmetry. Moreover, the\nalgorithm shows no critical slowing down even in the massless limit and can\nhence handle the massless Goldstino mode emerging in the supersymmetry broken\nphase. In this paper -- the third in a series of three -- we present the\ndetails of the simulation algorithm and demonstrate its efficiency by means of\na few examples."
    },
    {
        "anchor": "Cutoff effects on lattice nuclear forces: We present a lattice QCD study for the cutoff effects on nuclear forces.\nTwo-nucleon forces are determined from Nambu-Bethe-Salpeter (NBS) wave\nfunctions using the HAL QCD method. Lattice QCD simulations are performed\nemploying N_f = 2 clover fermion configurations at three lattice spacings of a\n= 0.108, 0.156, 0.215 fm on a fixed physical volume of L^3 x T = (2.5 fm)^3 x 5\nfm with a large quark mass corresponding to m_\\pi = 1.1 GeV. We observe that\nwhile the discretization artifact appears at the short range part of\npotentials, it is suppressed at the long distance region. The cutoff dependence\nof the phase shifts and scattering length is also presented.",
        "positive": "The equation of state of quark-gluon matter from lattice QCD with two\n  flavors of twisted-mass Wilson fermions: We report on lattice QCD results for the thermodynamic equation of state of\nquark-gluon matter obtained with Nf=2 degenerate quark flavors. For the fermion\nfield discretization we are using the Wilson-twisted mass prescription.\nSimulations have been carried out at three values of the bare quark masses\ncorresponding to pion masses of 360, 430 and 640 MeV. We highlight the\nimportance of a good control of the lattice cutoff dependence of the trace\nanomaly which we have studied at several values of the inverse temperature 1/T\n= a Nt with a time-like lattice extent up to Nt=12. We contrast our results\nwith those of other groups obtained for Nf=0 and Nf=2+1. At low temperature we\nalso confront them with hadron resonance gas model predictions for the trace\nanomaly."
    },
    {
        "anchor": "Reweighted complex Langevin and its application to two-dimensional QCD: We present the reweighted complex Langevin method, which enlarges the\napplicability range of the complex Langevin method by reweighting the complex\ntrajectories. In this reweighting procedure both the auxiliary and target\nensembles have a complex action. We validate the method by applying it to\ntwo-dimensional strong-coupling QCD at nonzero chemical potential, and observe\nthat it gives access to parameter regions that could otherwise not be reached\nwith the complex Langevin method.",
        "positive": "Study of charmonium-nucleon interaction in lattice QCD: We report preliminary results for charmonium-nucleon potential $V_{c\\bar{c}\nN}(r)$ from quenched lattice QCD, which is calculated from the equal-time\nBethe-Salpeter amplitude through the effective Schr\\\"odinger equation. Our\nsimulations are performed at a lattice cutoff of $1/a$=2.0 GeV in a spatial\nvolume of $(3\\;\\text{fm})^3$ with the nonperturbatively $O(a)$ improved Wilson\naction for the light quarks and a relativistic heavy quark action for the charm\nquark. We have found that the potential $V_{c\\bar{c} N}(r)$ is weakly\nattractive at short distance and exponentially screened at long distance."
    },
    {
        "anchor": "One-loop renormalization of the QCD Schr\u00f6dinger functional: In a previous publication, we have constructed the Schr\\\"odinger functional\nin Wilson's lattice QCD. It was found that the naive continuum limit leads to a\nwell-defined classical continuum theory. Starting from the latter, a formal\ncontinuum definition of the Schr\\\"odinger functional is given and its saddle\npoint expansion is carried out to one-loop order of perturbation theory.\nDimensional regularization and heat kernel techniques are used to determine the\none-loop divergences. These are partly canceled by the usual renormalizations\nof the quark mass and the coupling constant in QCD. An additional divergence\ncan be absorbed in a multiplicative renormalization of the quark boundary\nfields. The corresponding boundary counterterm is a local polynomial in the\nfields, so that we confirm a general expectation of Symanzik.",
        "positive": "Spontaneous Breaking of Flavor Symmetry and Parity in the\n  Nambu-Jona-Lasinio Model with Wilson Fermions: We study the lattice \\njl~model with two flavors of Wilson fermions in the\nlarge $N$ limit, where $N$ is the number of `colors'. For large values of the\nfour-fermion coupling we find a phase in which both, flavor symmetry and\nparity, are spontaneously broken. In accordance with general expectations there\nare three massless pions on the phase boundary, but only two of them remain\nmassless inside the broken phase. This is analogous to earlier results obtained\nin lattice QCD, indicating that this behavior is a very general feature of the\nWilson term."
    },
    {
        "anchor": "Cumulants and ordering of their ratios in 2D Potts models: Lessons for\n  QCD?: Theoretical considerations suggest an ordering of the ratios of net-baryon\nnumber fluctuations in the vicinity of the transition from the low-temperature\nhadronic phase to the high temperature quark-gluon plasma phase at small values\nof the baryon chemical potential, $\\mu_B$, in the QCD phase diagram. The\nordering hierarchy is $\\frac{\\chi_6}{\\chi_2} < \\frac{\\chi_5}{\\chi_1} <\n\\frac{\\chi_4}{\\chi_2} < \\frac{\\chi_3}{\\chi_1}$, where $\\chi_n$ is the\n$n^\\mathrm{th}$ order cumulant of net-baryon number fluctuation. The STAR\nexperiment observed this hierarchy in the ordering of cumulant ratios of\nnet-proton number (a proxy of net-baryon number) for a range of colliding\nenergies. These inequalities can be tested in spin models by taking the\ncorresponding order parameters in the model as an analog of baryon density. We\nemployed two different models: the two-state and three-state Potts models in\ntwo dimensions, which undergo a transition from an ordered phase to a\ndisordered phase at their respective critical temperature. Simulations were\nperformed on square lattices of different sizes using the Wolff algorithm. The\ncumulants of total magnetization are obtained up to the sixth order in both of\nthese models in a temperature range near their corresponding critical\ntemperatures. With increasing lattice size, height (trough) of the peaks (dips)\nof the higher-order cumulants appears to increase with the increase in the\norder of the cumulants. Except in a narrow range above the critical temperature\nof the three-state Potts model, the complete inequality or its complete reverse\nis not satisfied in the temperature ranges simulated.",
        "positive": "Can a Logarithmically Running Coupling Mimic a String Tension?: It is shown that a Coulomb potential using a running coupling slightly\nmodified from the perturbative form can produce an interquark potential that\nappears nearly linear over a large distance range. Recent high-statistics SU(2)\nlattice gauge theory data fit well to this potential without the need for a\nlinear string-tension term. This calls into question the accuracy of string\ntension measurements which are based on the assumption of a constant\ncoefficient for the Coulomb term. It also opens up the possibility of obtaining\nan effectively confining potential from gluon exchange alone."
    },
    {
        "anchor": "RI/MOM renormalization of the quasi-PDF in lattice regularization: We analyze the lattice spacing dependence for the pion unpolarized matrix\nelement of a quark bilinear operator with Wilson link (quasi-PDF operator) in\nthe rest frame, using 13 lattice spacings ranging from 0.032 fm to 0.121 fm. We\ncompare results for three different fermion actions with or without good chiral\nsymmetry on dynamical gauge ensembles from three collaborations. This\ninvestigation is motivated by the fact that the gauge link generates an $1/a$\ndivergence, the cancelation of which in many ratios can be numerically tricky.\nIndeed, our results show that this cancelation deteriorates with decreasing\nlattice spacing, and that the RI/MOM method leaves a linearly divergent residue\nfor quasi-PDFs. We also show that in the Landau gauge the interaction between\nthe Wilson link and the external state results in a linear divergence which\ndepends on the discretized fermion action.",
        "positive": "Volume Dependence of N-Body Bound States: We derive the finite-volume correction to the binding energy of an N-particle\nquantum bound state in a cubic periodic volume. Our results are applicable to\nbound states with arbitrary composition and total angular momentum, and in any\nnumber of spatial dimensions. The only assumptions are that the interactions\nhave finite range. The finite-volume correction is a sum of contributions from\nall possible breakup channels. In the case where the separation is into two\nbound clusters, our result gives the leading volume dependence up to\nexponentially small corrections. If the separation is into three or more\nclusters, there is a power-law factor that is beyond the scope of this work,\nhowever our result again determines the leading exponential dependence. We also\npresent two independent methods that use finite-volume data to determine\nasymptotic normalization coefficients. The coefficients are useful to determine\nlow-energy capture reactions into weakly bound states relevant for nuclear\nastrophysics. Using the techniques introduced here, one can even extract the\ninfinite-volume energy limit using data from a single-volume calculation. The\nderived relations are tested using several exactly solvable systems and\nnumerical examples. We anticipate immediate applications to lattice\ncalculations of hadronic, nuclear, and cold atomic systems."
    },
    {
        "anchor": "Static-light meson-meson potentials: We investigate potentials between pairs of static-light mesons in Nf=2\nLattice QCD, in different spin channels. The question of attraction and\nrepulsion is particularly interesting with respect to the X(3872) charmonium\nstate and charged candidates such as the Z+(4430). We employ the\nnonperturbatively improved Sheikholeslami-Wohlert fermion and the Wilson gauge\nactions at a lattice spacing a approx. 0.084 fm and a pseudoscalar mass mPS\napprox. 760 MeV. We use stochastic all-to-all propagator techniques, improved\nby a hopping parameter expansion. The analysis is based on the variational\nmethod, utilizing various source and sink interpolators.",
        "positive": "Meson masses and decay constants from unquenched lattice QCD: We report results for the masses of the flavour non-singlet light 0++, 1--,\nand 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted\nmass formalism was used with two flavours of sea quarks. For the 0++ and 1+-\nmesons we look for the effect of decays on the mass dependence. For the light\nvector mesons we study the chiral extrapolations of the mass. We report results\nfor the leptonic and transverse decay constants of the rho meson. We test the\nmass dependence of the KRSF relations."
    },
    {
        "anchor": "Introduction to stochastic error correction methods: We propose a method for eliminating the truncation error associated with any\nsubspace diagonalization calculation. The new method, called stochastic error\ncorrection, uses Monte Carlo sampling to compute the contribution of the\nremaining basis vectors not included in the initial diagonalization. The method\nis part of a new approach to computational quantum physics which combines both\ndiagonalization and Monte Carlo techniques.",
        "positive": "Hadron masses and baryonic scales in $G_2$-QCD at finite density: The QCD phase diagram at densities relevant to neutron stars remains elusive,\nmainly due to the fermion-sign problem. At the same time, a plethora of\npossible phases has been predicted in models. Meanwhile $G_2$-QCD, for which\nthe $SU(3)$ gauge group of QCD is replaced by the exceptional Lie group $G_2$,\ndoes not have a sign problem and can be simulated at such densities using\nstandard lattice techniques. It thus provides benchmarks to models and\nfunctional continuum methods, and it serves to unravel the nature of possible\nphases of strongly interacting matter at high densities. Instrumental in\nunderstanding these phases is that $G_2$-QCD has fermionic baryons, and that it\ncan therefore sustain a baryonic Fermi surface. Because the baryon spectrum of\n$G_2$-QCD also contains bosonic diquark and probably other more exotic states,\nit is important to understand this spectrum before one can disentangle the\ncorresponding contributions to the baryon density. Here we present the first\nsystematic study of this spectrum from lattice simulations at different quark\nmasses. This allows us to relate the mass hierarchy, ranging from scalar\nwould-be-Goldstone bosons and intermediate vector bosons to the $G_2$-nucleons\nand deltas, to individual structures observed in the total baryon density at\nfinite chemical potential."
    },
    {
        "anchor": "Faddeev-Popov Matrix in Linear Covariant Gauge: First Results: We discuss a possible definition of the Faddeev-Popov matrix for the minimal\nlinear covariant gauge on the lattice and present first results for the ghost\npropagator. We consider Yang-Mills theory in four space-time dimensions, for\nSU(2) and SU(3) gauge groups.",
        "positive": "QCD with dynamical Wilson fermions - first results from SESAM: First results of a recently started simulation of full QCD with two flavours\nof sea-quarks at a coupling of $\\beta = 5.6$ on a $16^3 \\times 32$ lattice are\npresented. Emphasis is laid on the statistical significance that can be\nachieved by an ``integrated luminosity'' of 140 TFlop$\\times$hrs, for Hybrid\nMonte Carlo simulations at four intermediate values of\n$\\frac{m_{\\pi}}{m_{\\rho}}$. The simulation takes place on the Quadrics QH2 at\nDESY/Zeuthen and DFG/Bielefeld. The performance is optimized by means of\nBiCGStab and the chronological inversion method of Brower et al. We discuss the\nsystematic errors arising from lack of the molecular dynamic's reversibility on\nthe 32-bit QH2. For plaquette and meson correlators we find integrated\nautocorrelation times of $< 20$ units of molecular dynamics time and\nexponential autocorrelation times of about $50$ units. Using these results we\nperform preliminary measurements of the central potential and $\\pi$ and $\\rho$\ncorrelators on independent configurations and obtain first estimates of the\nlattice spacings at three values of the dynamical hopping parameter."
    },
    {
        "anchor": "QCD Thermodynamics with Almost Realistic Quark Masses: Ongoing calculations on the QCDOC supercomputer at Brookhaven National\nLaboratory and the APEnext installation at the University of Bielefeld aim to\ndetermine the critical temperature of the QCD phase transition as well as the\nequation of state with almost realistic quark masses. We will discuss\npreliminary results of the quark mass and cut-off dependence of order\nparameters, susceptibilities, static quark potentials and the critical\ntemperature in (2+1)-flavor QCD. All these quantities are of immediate interest\nfor heavy ion phenomenology.",
        "positive": "The QCD equation of state to $\\mathcal{O}(\u03bc_B^4)$: We present results from an ongoing calculation of the QCD equation of state\nat finite baryon chemical potential $\\mu_B$. We use the method of Taylor\nexpansions to circumvent the sign problem and calculate the expansion\ncoefficients to sixth order using HISQ fermions. We work at two lattice\nspacings, namely $N_\\tau=6$ and 8 and, though we do not take the continuum\nlimit, demonstrate that cutoff effects remain under control. We also use our\nresults to construct an equation of state along the freeze-out curve. Using our\nsixth-order results as a cross-check, we demonstrate that our fourth-order\nequation of state is suitable for the modeling of dense matter created in heavy\nion collisions with center-of-mass energies down to $s_{NN}^{1/2}\\sim20$ GeV."
    },
    {
        "anchor": "Renormalization of Supersymmetric QCD on the Lattice: We perform a pilot study of the perturbative renormalization of a\nSupersymmetric gauge theory with matter fields on the lattice. As a specific\nexample, we consider Supersymmetric ${\\cal N}{=}1$ QCD (SQCD). We study the\nself-energies of all particles which appear in this theory, as well as the\nrenormalization of the coupling constant. To this end we compute,\nperturbatively to one-loop, the relevant two-point and three-point Green's\nfunctions using both dimensional and lattice regularizations. Our lattice\nformulation involves the Wilson discretization for the gluino and quark fields;\nfor gluons we employ the Wilson gauge action; for scalar fields (squarks) we\nuse naive discretization. The gauge group that we consider is $SU(N_c)$, while\nthe number of colors, $N_c$, the number of flavors, $N_f$, and the gauge\nparameter, $\\alpha$, are left unspecified.\n  We obtain analytic expressions for the renormalization factors of the\ncoupling constant ($Z_g$) and of the quark ($Z_\\psi$), gluon ($Z_u$), gluino\n($Z_\\lambda$), squark ($Z_{A_\\pm}$), and ghost ($Z_c$) fields on the lattice.\nWe also compute the critical values of the gluino, quark and squark masses.\nFinally, we address the mixing which occurs among squark degrees of freedom\nbeyond tree level: we calculate the corresponding mixing matrix which is\nnecessary in order to disentangle the components of the squark field via an\nadditional finite renormalization.",
        "positive": "Lattice QCD study of mixed systems of pions and kaons: The different ground state energies of N-pion and M-kaon systems for N+M <=12\nare studied in lattice QCD. These energies are then used to extract the various\ntwo- and three- body interactions that occur in these systems. Particular\nattention is paid to additional thermal states present in the spectrum because\nof the finite temporal extent. These calculations are performed using one\nensemble of 2+1 flavor anisotropic lattices with a spatial lattice spacing a_s\n~ 0.125 fm, an anisotropy factor {\\xi}=a_s/a_t=3.5, and a spatial volume L^3 ~\n(2.5 fm)^3. The quark masses used correspond to pion and kaon masses of m_{\\pi}\n~ 383 MeV and m_K ~ 537 MeV, respectively. The isospin and strangeness chemical\npotentials of these systems are found to be in the region where chiral\nperturbation theory and hadronic models predict a phase transition between a\npion condensed phase and a kaon condensed phase."
    },
    {
        "anchor": "Generalised Spin Projection for Fermion Actions: The majority of compute time doing lattice QCD is spent inverting the fermion\nmatrix. The time that this takes increases with the condition number of the\nmatrix. The FLIC(Fat Link Irrelevant Clover) action displays, among other\nproperties, an improved condition number compared to standard actions and hence\nis of interest due to potential compute time savings. However, due to its two\ndifferent link sets there is a factor of two cost in floating point\nmultiplications compared to the Wilson action. An additional factor of two has\nbeen attributed due to the loss of the so-called spin projection trick. We show\nthat any split-link action may be written in terms of spin projectors, reducing\nthe additional cost to at most a factor of two. Also, we review an efficient\nmeans of evaluating the clover term, which is additional expense not present in\nthe Wilson action.",
        "positive": "Chiral phase transition in lattice QCD as a metal-insulator transition: We investigate the lattice QCD Dirac operator with staggered fermions at\ntemperatures around the chiral phase transition. We present evidence of a\nmetal-insulator transition in the low lying modes of the Dirac operator around\nthe same temperature as the chiral phase transition. This strongly suggests the\nphenomenon of Anderson localization drives the QCD vacuum to the chirally\nsymmetric phase in a way similar to a metal-insulator transition in a\ndisordered conductor. We also discuss how Anderson localization affects the\nusual phenomenological treatment of phase transitions a la Ginzburg-Landau."
    },
    {
        "anchor": "Dynamical fermions on anisotropic lattices: We report on our study of two-flavor full QCD on anisotropic lattices using\n$O(a)$-improved Wilson quarks coupled with an RG-improved glue. The bare gauge\nand quark anisotropies corresponding to the renormalized anisotropy\n$\\xi=a_s/a_t = 2$ are determined as functions of $\\beta$ and $\\kappa$, using\nthe Wilson loop and the meson dispersion relation at several lattice cutoffs\nand quark masses.",
        "positive": "Remnants of quark model in lattice QCD simulation in the Coulomb gauge: Aiming at the relation between QCD and the quark model, we consider\nprojections of gauge configurations generated in quenched lattice QCD\nsimulations in the Coulomb gauge on a $16^3 \\times 32, \\beta = 6.0$ lattice.\nFirst, we focus on a fact that the static quark-antiquark potential is\nindependent of spatial gauge fields. We explicitly confirm this by performing\n$\\vec{A} = 0$ projection, where spatial gauge fields are all set to zero. We\nalso apply the $\\vec{A} = 0$ projection to light hadron masses and find that\nnucleon and delta baryon masses are almost degenerate, suggesting vanishing of\nthe color-magnetic interactions. After considering the physical meaning of the\n$\\vec{A} = 0$ projection, we next propose a generalized projection, where\nspatial gauge fields are expanded in terms of Faddeev-Popov eigenmodes and only\nsome eigenmodes are left. We apply the proposed projection to light hadron and\nglueball masses and find that the $N-\\Delta$ and $0^{++}-2^{++}$ mass\nsplittings become evident when projected with more than 33 (0.10 \\%) low-lying\neigenmodes, suggesting emergence of the color-magnetic interactions. We also\nfind that the original hadron masses are approximately reproduced with just 328\n(1.00 \\%) low-lying eigenmodes. These findings indicate an important role of\nlow-lying eigenmodes on hadron masses and would be useful in clarifying the\nrelation between QCD and the quark model."
    },
    {
        "anchor": "Dependence of the propagators on the sampling of Gribov copies inside\n  the first Gribov region of Landau gauge: Beyond perturbation theory the number of gauge copies drastically increases\ndue to the Gribov-Singer ambiguity. Any way of treating them defines, in\nprinciple, a new, non-perturbative gauge, and the gauge-dependent correlation\nfunctions can vary between them. Herein various such gauges will be constructed\nas completions of the Landau gauge inside the first Gribov region. The\ndependence of the propagators and the running coupling on these gauges will be\nstudied for SU(2) Yang-Mills theory in two, three, and four dimensions using\nlattice gauge theory, and for a wide range of lattice parameters. While the\ngluon propagator is rather insensitive to the choice, the ghost propagator and\nthe running coupling show a stronger dependence. It is also found that the\ninfluence of lattice artifacts is larger than in minimal Landau gauge.",
        "positive": "Isospin-breaking Effects in Octet and Decuplet Baryon Masses: We present work designed to compute baryon masses on $N_f = 2 + 1$ CLS\nensembles including isospin-breaking effects due to non-degenerate light quark\nmasses and electromagnetic interactions. These effects are determined at\nleading order via a perturbative expansion around the iso-symmetric theory. We\nfurthermore apply a group-theoretical operator construction for the various\ninterpolators describing the different members of the baryon octet and decuplet\nbased on a classification by spin, parity, and flavor content."
    },
    {
        "anchor": "Excited state baryon spectroscopy from lattice QCD with spin\n  identification: Lattice QCD calculations are presented for the spectra of N* excited states\nwith spins up to J = 7/2. Ambiguities of the standard method of spin\nidentification are shown to be overcome by the use of lattice operators that\ntransform according to SU(2) symmetry restricted to the lattice. Such operators\nare labeled by their continuum spins. Overlaps of the operators with the states\nobtained by diagonalizing matrices of correlation functions provide a clear\nlink between continuum spins and lattice states, allowing spins to be\nidentified. Evidence for an approximate realization of rotational symmetry in\nthe N* spectrum is presented. In simulations with pion mass = 392 MeV, the\nlow-lying excited states of lattice QCD are found to have the same quantum\nnumbers as the states of SU(6)xO(3) symmetry. The lattice spectra are\ninconsistent with either a quark-diquark model or parity doubling of states and\nthey suggest that the J = 1/2 Roper resonance may have a complex structure\nconsisting of contributions from L=0, 1 and 2.",
        "positive": "Heavy-light current-current correlators: The current-current correlator method has been used successfully to obtain\nvery accurate results for quark masses and the coupling alpha_s. The\ncalculations were done using Highly Improved Staggered Quarks (HISQ) and\nheavy-heavy meson correlators. We now extend this work to the significantly\nmore challenging heavy-light case, reporting the first results here. The aim is\nto determine nonperturbative Z factors for NRQCD heavy-light currents, but\nfirst we test the method in the HISQ case where Z=1."
    },
    {
        "anchor": "Studying glueball masses in non-Abelian LGT with the LW algorithm: We address a study of glueball masses in the confining regime of SU(2) in D=3\nusing an algorithm inspired by the multi-level scheme. Our method, which\nexploits the locality of the action to achieve high precision results, is based\non a technique already used for compact QED, and generalises it to the\nnon-Abelian case. We discuss the main features of this method, in comparison\nwith other algorithms that have been used in similar studies.",
        "positive": "Symmetries of Ginsparg-Wilson Chiral Fermions: The group structure of the variant chiral symmetry discovered by Luscher in\nthe Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is\nshown that the group contains an infinite number of linearly independent\nsymmetry generators, and the Lie algebra is given explicitly. CP is an\nautomorphism of this extended chiral group, and the CP transformation\nproperties of the symmetry generators are found. The group has an\ninfinite-parameter invariant subgroup, and the factor group, whose elements are\nits cosets, is isomorphic to the continuum chiral symmetry group. Features of\nthe currents associated with these symmetries are discussed, including the fact\nthat some different, non-commuting symmetry generators lead to the same Noether\ncurrent. These are universal features of lattice chiral fermions based on the\nGinsparg-Wilson relation; they occur in the overlap, domain-wall, and\nperfect-action formulations. In a solvable example, free overlap fermions,\nthese non-canonical elements of lattice chiral symmetry are related to complex\nenergy singularities that violate reflection positivity and impede continuation\nto Minkowski space."
    },
    {
        "anchor": "Many flavor approach to study the critical point in finite density QCD: We discuss the QCD critical point at finite density through the study of many\nflavor QCD, in which two light flavors and Nf massive flavors exist. Performing\nsimulations of QCD with two flavors of improved Wilson fermions, we calculate\nprobability distribution functions of many flavor QCD at finite temperature and\ndensity. The dynamical effects of massive flavors and the chemical potential\nare added using the reweighting technique. From the shape of the distribution\nfunctions, we determine the critical surface separating the first order\ntransition and crossover regions in the parameter space of the light and\nmassive quark masses and the chemical potentials. It is found that the critical\nmassive quark mass becomes larger as the chemical potential increases in (2+Nf)\nflavor QCD. The indication to the (2+1) flavor QCD is then discussed.",
        "positive": "Meron- and Semi-Vortex-Clusters as Physical Carriers of Topological\n  Charge and Vorticity: In O($N$) non-linear $\\sigma$-models on the lattice, the Wolff cluster\nalgorithm is based on rewriting the functional integral in terms of mutually\nindependent clusters. Through improved estimators, the clusters are directly\nrelated to physical observables. In the $(N-1)$-d O($N$) model (with an\nappropriately constrained action) the clusters carry an integer or half-integer\ntopological charge. Clusters with topological charge $\\pm 1/2$ are denoted as\nmerons. Similarly, in the 2-d O(2) model the clusters carry pairs of\nsemi-vortices and semi-anti-vortices (with vorticity $\\pm 1/2$) at their\nboundary. Using improved estimators, meron- and semi-vortex-clusters provide\nanalytic insight into the topological features of the dynamics. We show that\nthe histograms of the cluster-size distributions scale in the continuum limit,\nwith a fractal dimension $D$, which suggests that the clusters are physical\nobjects. We demonstrate this property analytically for merons and non-merons in\nthe 1-d O(2) model (where $D=1$), and numerically for the 2-d O(2), 2-d O(3),\nand 3-d O(4) model, for which we observe fractal dimensions $D < d$. In the\nvicinity of a critical point, a scaling law relates $D$ to a combination of\ncritical exponents. In the 2-d O(3) model, meron- and multi-meron-clusters are\nresponsible for a logarithmic ultraviolet divergence of the topological\nsusceptibility."
    },
    {
        "anchor": "Multiple-channel generalization of Lellouch-L\u00fcscher formula: Lattice\n  2012 conference proceedings: We describe a generalization of the Lellouch-L\\\"uscher formula to the case of\nmultiple strongly-coupled decay channels. As in the original formula, our final\nresult is a relation between weak matrix elements in finite and infinite\nvolumes. Our extension is limited to final states with two scalar particles,\nwith center of mass energies below the lowest three- or four-particle\nthreshold. Otherwise the extension is general, accommodating any number of\nchannels, arbitrary strong coupling between channels, as well as any form of\nweak decay operators in the matrix elements. Among many possible applications,\nwe emphasize that this is a necessary first step on the way to a lattice-QCD\ncalculation of weak decay rates for D -> pi pi and D -> K K-bar. Our results\nallow for arbitrary total momentum and hold for degenerate or non-degenerate\nparticles.",
        "positive": "Gluon momentum fraction of the nucleon from lattice QCD: We perform a direct calculation of the gluon momentum fraction of the nucleon\nusing maximally twisted mass fermion ensembles with $N_f=2+1+1$ flavors at a\npion mass of about $370\\,\\mathrm{MeV}$ and a lattice spacing of $a\\approx\n0.082\\,\\mathrm{fm}$ and with $N_f=2$ flavors at the physical pion mass and a\nlattice spacing of $a\\approx 0.093\\,\\mathrm{fm}$. In the definition of the\ngluon operator we employ stout smearing to obtain a statistically significant\nresult for the bare matrix elements. In addition, we perform a lattice\nperturbative calculation including 2 levels of stout smearing to carry out the\nmixing and the renormalization of the quark and gluon operators. We find, after\nconversion to the $\\overline{\\mathrm{MS}}$ scheme at a scale of\n$2\\,\\mathrm{GeV}$: $\\langle x\\rangle^R_g {=} 0.284(23)(23)$ for pion mass of\nabout $370\\,\\mathrm{MeV}$ and $\\langle x\\rangle^R_g {=} 0.283(23)(15)$ for the\nphysical pion mass."
    },
    {
        "anchor": "Numerical Computations in the Worldsheet Formulation: The worldsheet formulation of lattice gauge theories has two appealing\nfeatures: the gauge non-redundancy and the geometrical transparency. Both\nproperties are profitable in order to perform numerical computations. In the\ncase of dynamical fermions this description offers additional advantages. For\ninstance, it does not suffer from the species doubling problem and it involves\nfewer degrees of freedom.",
        "positive": "Simulating the All-Order Strong Coupling Expansion V: Ising Gauge Theory: We exactly rewrite the Z(2) lattice gauge theory with standard plaquette\naction as a random surface model equivalent to the untruncated set of its\nstrong coupling graphs. By extending the worm approach applied to spin models\nwe simulate such surfaces including Polyakov line defects that randomly walk\nover the lattice. Our Monte Carlo algorithms for the graph ensemble are\nreasonably efficient but not free of critical slowing down. Polyakov line\ncorrelators can be measured in this approach with small relative errors that\nare independent of the separation. As a first application our results are\nconfronted with effective string theory predictions. In addition, the excess\nfree energy due to twisted boundary conditions becomes an easily accessible\nobservable. Our numerical experiments are in three dimensions, but the method\nis expected to work in any dimension."
    },
    {
        "anchor": "$\u039b_c \\to \u039b^*(1520)$ form factors from lattice QCD and\n  improved analysis of the $\u039b_b \\to \u039b^*(1520)$ and $\u039b_b \\to\n  \u039b_c^*(2595,2625)$ form factors: We present the first lattice-QCD calculation of the form factors governing\nthe charm-baryon semileptonic decays $\\Lambda_c \\to\n\\Lambda^*(1520)\\ell^+\\nu_\\ell$. As in our previous calculation of the\n$\\Lambda_b \\to \\Lambda^*(1520)$ form factors, we work in the $\\Lambda^*(1520)$\nrest frame, but here we use four different heavy-baryon momenta instead of just\ntwo. Because of the lower mass of the $\\Lambda_c$, the moderately-sized momenta\nused here are sufficient to determine the form factors in the full kinematic\nrange of the semileptonic decay. We also update the analysis of our lattice\nresults for the $\\Lambda_b \\to \\Lambda^*(1520)$ and $\\Lambda_b \\to\n\\Lambda_c^*(2595,2625)$ form factors by imposing exact relations among the\ndifferent form factors at zero recoil that follow from rotational symmetry.\nImposing these relations ensures the correct behavior of the angular\nobservables near the endpoint.",
        "positive": "Universality, Scaling and Topology with a Modified Lattice Action: We examined the effect of a complete suppression of a lattice artifact, the\nnegative plaquettes, on physical quantities, such as the critical temperature,\nthe string tension, the topological charge, glueball masses, and their ratios."
    },
    {
        "anchor": "Ground State Entropy in Potts Antiferromagnets and Chromatic Polynomials: We discuss recent results on ground state entropy in Potts antiferromagnets\nand connections with chromatic polynomials. These include rigorous lower and\nupper bounds, Monte Carlo measurements, large--$q$ series, exact solutions, and\nstudies of analytic properties. Some related results on Fisher zeros of Potts\nmodels are also mentioned.",
        "positive": "Finite Size Scaling for O(N) phi^4-Theory at the Upper Critical\n  Dimension: A finite size scaling theory for the partition function zeros and\nthermodynamic functions of O(N) phi^4-theory in four dimensions is derived from\nrenormalization group methods. The leading scaling behaviour is mean-field like\nwith multiplicative logarithmic corrections which are linked to the triviality\nof the theory. These logarithmic corrections are independent of N for odd\nthermodynamic quantities and associated zeros and are N dependent for the even\nones. Thus a numerical study of finite size scaling in the Ising model serves\nas a non-perturbative test of triviality of phi^4_4-theories for all N."
    },
    {
        "anchor": "Quark Confinement and Surface Critical Phenomena: Surface critical phenomena and the related onset of Goldstone modes probe the\nfundamental properties of the confining flux in Quantum Chromodynamics. New\nideas on surface roughening and their implications for lattice studies of quark\nconfinement are presented. Problems with the oversimplified string description\nof the Wilson flux sheet are discussed.",
        "positive": "The Mellin moments $\\langle x \\rangle$ and $\\langle x^2 \\rangle$ for the\n  pion and kaon from lattice QCD: We present a calculation of the pion quark momentum fraction, $\\langle x\n\\rangle$, and its third Mellin moment $\\langle x^2 \\rangle$. We also obtain\ndirectly, for the first time, $\\langle x \\rangle$ and $\\langle x^2 \\rangle$ for\nthe kaon using local operators. We use an ensemble of two degenerate light, a\nstrange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with\nclover improvement. The quark masses are chosen so that they reproduce a pion\nmass of about 260 MeV, and a kaon mass of 530 MeV. The lattice spacing of the\nensemble is 0.093 fm and the lattice has a spatial extent of 3 fm. We analyze\nseveral values of the source-sink time separation within the range of\n$1.12-2.23$ fm to study and eliminate excited-states contributions. The\nnecessary renormalization functions are calculated non-perturbatively in the\nRI$'$ scheme, and are converted to the $\\overline{\\rm MS}$ scheme at a scale of\n2 GeV. The final values for the momentum fraction are $\\langle x\n\\rangle^\\pi_{u^+}=0.261(3)_{\\rm stat}(6)_{\\rm syst}$, $\\langle x\n\\rangle^K_{u^+}=0.246(2)_{\\rm stat}(2)_{\\rm syst}$, and $\\langle x\n\\rangle^K_{s^+}=0.317(2)_{\\rm stat}(1)_{\\rm syst}$. For the third Mellin\nmoments we find $\\langle x^2 \\rangle^\\pi_{u^+}=0.082(21)_{\\rm stat}(17)_{\\rm\nsyst}$, $\\langle x^2 \\rangle^K_{u^+}=0.093(5)_{\\rm stat}(3)_{\\rm syst}$, and\n$\\langle x^2 \\rangle^K_{s^+}=0.134(5)_{\\rm stat}(2)_{\\rm syst}$. The reported\nsystematic uncertainties are due to excited-state contamination. We also give\nthe ratio $\\langle x^2 \\rangle/\\langle x \\rangle$ which is an indication of how\nquickly the PDFs lose support at large $x$."
    },
    {
        "anchor": "Multiple Potts Models Coupled to Two-Dimensional Quantum Gravity: We perform Monte Carlo simulations using the Wolff cluster algorithm of {\\it\nmultiple} $q=2,3,4$ state Potts models on dynamical phi-cubed graphs of\nspherical topology in order to investigate the $c>1$ region of two-dimensional\nquantum gravity. Contrary to naive expectation we find no obvious signs of\npathological behaviour for $c>1$. We discuss the results in the light of\nsuggestions that have been made for a modified DDK ansatz for $c>1$.",
        "positive": "Staggered Baryon Operators with Flavor SU(3) Quantum Numbers: The construction of the first baryon operators for staggered lattice QCD\nexploited the taste symmetry to emulate physical quark flavor; contemporary 2+1\nflavor simulations explicitly include three physical quark flavors and\nnecessitate interpreting a valence sector with twelve quarks. After discussing\nexpected features of the resulting baryon spectrum, I consider the spectra of\noperators transforming irreducibly under SU(3)xGTS, the direct product of\nflavor SU(3) and the geometrical time-slice group of the 1-flavor staggered\ntheory. I then describe the construction of a set of maximally local baryon\noperators transforming irreducibly under SU(3)xGTS and enumerate this set. In\nprinciple, the operators listed here could be used to extract the masses of all\nthe lightest spin-1/2 and spin-3/2 baryon resonances of staggered QCD. Using\nappropriate operators from this set in partially quenched simulations should\nallow for particularly clean 2+1 flavor calculations of the masses of the\nnucleon and the lightest decuplet."
    },
    {
        "anchor": "Scaling behavior of improvement and renormalization constants: This talk summarizes results for all the scale independent renormalization\nconstants for bilinear currents ($Z_A$, $Z_V$, and $Z_S/Z_P$), the improvement\nconstants ($c_A$, $c_V$, and $c_T$), the quark mass dependence of $Z_O$, and\nthe coefficients of the equation of motion operators for $O(a)$ improved\nlattice QCD. Using data at $\\beta=6.0$, 6.2 and 6.4 we study the scaling\nbehavior of these quantities and quantify residual discretization errors.",
        "positive": "Ultraviolet filtering of lattice configurations and applications to\n  Monte Carlo dynamics: We present a detailed study of a filtering method based upon Dirac\nquasi-zero-modes in the adjoint representation. The procedure induces no\ndistortions on configurations which are solutions of the euclidean classical\nequations of motion. On the other hand, it is very effective in reducing the\nshort-wavelength stochastic noise present in Monte Carlo generated\nconfigurations. After testing the performance of the method in various\nsituations, we apply it successfully to study the effect of Monte Carlo\ndynamics on topological structures like instantons."
    },
    {
        "anchor": "Nucleon Magnetic Moments and Electric Polarizabilities: Electromagnetic properties of the nucleon are explored with lattice QCD using\na novel technique. Focusing on background electric fields, we show how the\nelectric polarizability can be extracted from nucleon correlation functions. A\ncrucial step concerns addressing contributions from the magnetic moment, which\naffects the relativistic propagation of nucleons in electric fields. By\nproperly handing these contributions, we can determine both magnetic moments\nand electric polarizabilities. Lattice results from anisotropic clover lattices\nare presented. Our method is not limited to the neutron; we show results for\nthe proton as well.",
        "positive": "Electromagnetic Structure of Light Baryons in Lattice QCD: A method in which electromagnetic properties of hadrons are studied by direct\nsimulation of dynamical photon effects is applied to the extraction of the\nisomultiplet structure of the octet baryons. Using 187 configurations at\n$\\beta=5.7$ with Wilson action, and up and down quark masses determined from\nthe meson spectrum, the nucleon splitting is found to be $1.55(\\pm 0.56\\; \\rm\nstat)$ MeV; the hyperon splittings are found to be\n$\\Sigma^{0}-\\Sigma^{+}=2.47\\pm 0.39$, $\\Sigma^{-}-\\Sigma^{0}=4.63\\pm 0.36$,\n$\\Xi^{-}-\\Xi^{0}=5.68\\pm 0.24$ MeV. Estimated systematic corrections arising\nfrom finite volume and the quenched approximation are included in these\nresults."
    },
    {
        "anchor": "Hard and thermal probes of QGP from the perspective of Lattice QCD: In this talk I review the current status of lattice QCD results on the hard\nand thermal probes of QGP, including jet quenching parameters, the melting of\nquarkonia and open heavy flavours, thermal photon/dilepton rates, electrical\nconductivity as well as heavy quark diffusion coefficients.",
        "positive": "Criterium for the index theorem on the lattice: We study how far the Index Theorem can be extrapolated from the continuum to\nfinite lattices with finite topological charge densities. To examine how the\nWilson action approximates the Index theorem, we specialize in the lattice\nversion of the Schwinger model. We propose a new criterion for solutions of the\nGinsparg-Wilson Relation constructed with the Wilson action. We conclude that\nthe Neuberger action is the simplest one that maximally complies with the Index\nTheorem, and that its best parameter in d=2 is m0=1.1 +- 0.1 ."
    },
    {
        "anchor": "Quark mass RG-running for $N_f$ =3 QCD in a $\u03c7SF$ setup: We compute the nonperturbative quark mass RG-running in the range\n$\\Lambda_{QCD}\\lessapprox\\mu\\lessapprox M_W$ for $N_f=3$ massless QCD with a\nmixed action approach: sea quarks are regularised using nonperturbatively\n$O(a)$-improved Wilson fermions with Schr\\\"odinger functional (SF) boundary\nconditions, employing the configurations of 1802.05243, while valence quarks\nare regularised using nonperturbatively $O(a)$-improved Wilson fermions with\nchirally rotated Schr\\\"odinger functional boundary conditions ($\\chi$SF). Our\nresult is compatible with its SF counterpart of ref.1802.05243, confirming the\nuniversality of $\\chi$SF and SF in the continuum limit. We also establish the\noptimal tuning strategy for the critical hopping parameter $\\kappa_c$ and the\n$\\chi$SF boundary counterterm coefficient $z_{\\rm f}$. We work in two energy\nregimes with two different definitions of the coupling: SF-coupling for 2 GeV\n$\\lessapprox\\mu\\lessapprox M_W$ and GF-coupling for $\\Lambda_{QCD}\n\\lessapprox\\mu\\lessapprox 2 GeV$.",
        "positive": "Reliability of Taylor expansions in QCD: We investigate the reliability of the Taylor expansion method in QCD with\nisospin chemical potentials using lattice simulations. By comparing the\nexpansion of the number density to direct results, the range of validity of the\nleading- and next-to-leading order expansions is determined. We also elaborate\non the convergence properties of the Taylor series by comparing the leading\nestimate for the radius of convergence to the position of the nearest\nsingularity, i.e. the onset of pion condensation. Our results provide a handle\nfor quantifying the uncertainties of Taylor expansions in baryon chemical\npotentials."
    },
    {
        "anchor": "Strange quark contributions to nucleon mass and spin from lattice QCD: Contributions of strange quarks to the mass and spin of the nucleon,\ncharacterized by the observables f_Ts and Delta s, respectively, are\ninvestigated within lattice QCD. The calculation employs a 2+1-flavor\nmixed-action lattice scheme, thus treating the strange quark degrees of freedom\nin dynamical fashion. Numerical results are obtained at three pion masses, m_pi\n= 495 MeV, 356 MeV, and 293 MeV, renormalized, and chirally extrapolated to the\nphysical pion mass. The value extracted for Delta s at the physical pion mass\nin the MSbar scheme at a scale of 2 GeV is Delta s = -0.031(17), whereas the\nstrange quark contribution to the nucleon mass amounts to f_Ts =0.046(11). In\nthe employed mixed-action scheme, the nucleon valence quarks as well as the\nstrange quarks entering the nucleon matrix elements which determine f_Ts and\nDelta s are realized as domain wall fermions, propagators of which are\nevaluated in MILC 2+1-flavor dynamical asqtad quark ensembles. The use of\ndomain wall fermions leads to mild renormalization behavior which proves\nespecially advantageous in the extraction of f_Ts.",
        "positive": "Charmed bottom baryon spectroscopy from lattice QCD: We calculate the masses of baryons containing one, two, or three heavy quarks\nusing lattice QCD. We consider all possible combinations of charm and bottom\nquarks, and compute a total of 36 different states with $J^P = \\frac12^+$ and\n$J^P = \\frac32^+$. We use domain-wall fermions for the up, down, and strange\nquarks, a relativistic heavy-quark action for the charm quarks, and\nnonrelativistic QCD for the bottom quarks. Our analysis includes results from\ntwo different lattice spacings and seven different pion masses. We perform\nextrapolations of the baryon masses to the continuum limit and to the physical\npion mass using $SU(4|2)$ heavy-hadron chiral perturbation theory including\n$1/m_Q$ and finite-volume effects. For the 14 singly heavy baryons that have\nalready been observed, our results agree with the experimental values within\nthe uncertainties. We compare our predictions for the hitherto unobserved\nstates with other lattice calculations and quark-model studies."
    },
    {
        "anchor": "Towards the super Yang-Mills spectrum at large $N_c$: We examine one-flavour $SU(N_c)$ gauge theories, where $N_c$ denotes the\nnumber of colors, with one fermion in the antisymmetric representation as a\ncandidate to approximate $\\mathcal{N}=1$ super Yang Mills due to their\nequivalence in the large-$N_c$ limit. Summarising results on spectral\nevaluations of $N_c=3$, we will report on the progress of dynamical\ncalculations for $N_c>3$. We discuss cut-off effects and challenges in\nconfiguration generation.",
        "positive": "Phase structure of lattice QCD with two flavors of Wilson quarks at\n  finite temperature and chemical potential: We present results for phase structure of lattice QCD with two degenerate\nflavors ($N_f=2$) of Wilson quarks at finite temperature $T$ and small baryon\nchemical potential $\\mu_B$. Using the imaginary chemical potential for which\nthe fermion determinant is positive, we perform simulations at points where the\nratios of pseudo-scalar meson mass to the vector meson mass $m_\\pi/m_\\rho$ are\nbetween $0.943(3)$ and $0.899(4)$ as well as in the quenched limit. By analytic\ncontinuation to real quark chemical potential $\\mu$, we obtain the transition\ntemperature as a function of small $\\mu_B$. We attempt to determine the nature\nof transition at imaginary chemical potential by histogram, MC history, and\nfinite size scaling. In the infinite heavy quark limit, the transition is of\nfirst order. At intermediate values of quark mass $m_q$ corresponding to the\nratio of $m_\\pi/m_\\rho$ in the range from $0.943(3)$ to $0.899(4)$ at\n$a\\mu_I=0.24$, the MC simulations show absence of phase transition."
    },
    {
        "anchor": "Nuclear matrix elements from lattice QCD for electroweak and\n  beyond-Standard-Model processes: Over the last decade, numerical solutions of Quantum Chromodynamics (QCD)\nusing the technique of lattice QCD have developed to a point where they are\nbeginning to connect fundamental aspects of nuclear physics to the underlying\ndegrees of freedom of the Standard Model. In this review, the progress of\nlattice QCD studies of nuclear matrix elements of electroweak currents and\nbeyond-Standard-Model operators is summarized, and connections with effective\nfield theories and nuclear models are outlined.\n  Lattice QCD calculations of nuclear matrix elements can provide guidance for\nlow-energy nuclear reactions in astrophysics, dark matter direct detection\nexperiments, and experimental searches for violations of the symmetries of the\nStandard Model, including searches for additional CP violation in the hadronic\nand leptonic sectors, baryon-number violation, and lepton-number or flavor\nviolation. Similarly, important inputs to neutrino experiments seeking to\ndetermine the neutrino-mass hierarchy and oscillation parameters, as well as\nother electroweak and beyond-Standard-Model processes can be determined. The\nphenomenological implications of existing studies of electroweak and\nbeyond-Standard-Model matrix elements in light nuclear systems are discussed,\nand future prospects for the field toward precision studies of these matrix\nelements are outlined.",
        "positive": "Geometric effects in lattice QCD thermodynamics: I present a study of the equation of state in quenched QCD, discussing some\nsystematic effects related to the lattice geometry. In particular, I comment on\nthe modification of the Stefan-Boltzmann law for a gas of free gluons in a\nfinite system, and study the impact it might have on numerical results at high\ntemperatures, for the typical parameters of current lattice simulations.\nFinally, I apply the results of this study to the analysis of data obtained\nfrom simulations of SU(N) gauge theories with N>3 colors, in a temperature\nrange up to 3T_c, where infrared effects appear to be under control.\nPreliminary results for various thermodynamic observables for SU(4), SU(5) and\nSU(6) gauge theories are found to be close to each other and to those for\nSU(3), in agreement with other similar studies. This may be relevant for the\ntheoretical description of the QCD plasma."
    },
    {
        "anchor": "Accurate exponents from approximate tensor renormalizations: We explain the recent numerical successes obtained by Tao Xiang's group, who\ndeveloped and applied Tensor Renormalization Group methods for the Ising model\non square and cubic lattices, by the fact that their new truncation method\nsharply singles out a surprisingly small subspace of dimension two. We show\nthat in the two-state approximation, their transformation can be handled\nanalytically yielding a value 0.964 for the critical exponent nu much closer to\nthe exact value 1 than 1.338 obtained in the Migdal-Kadanoff approximation. We\npropose two alternative blocking procedures that preserve the isotropy and\nimprove the accuracy to nu=0.987 and 0.993 respectively. We discuss\napplications to other classical lattice models, including models with fermions,\nand suggest that it could become a competitor for Monte Carlo methods suitable\nto calculate accurately critical exponents, take continuum limits and study\nnear-conformal systems in arbitrarily large volumes.",
        "positive": "Improved Quark Actions for Lattice QCD: I present a brief summary of the status and prospects of improved Wilson-type\nquark actions for coarse lattice simulations. My conclusions are optimistic."
    },
    {
        "anchor": "Generative learning for the problem of critical slowing down in lattice\n  Gross Neveu model: In lattice field theory, Monte Carlo simulation algorithms get highly\naffected by critical slowing down in the critical region, where autocorrelation\ntime increases rapidly. Hence the cost of generation of lattice configurations\nnear the critical region increases sharply. In this paper, we use a Conditional\nGenerative Adversarial Network (C-GAN) for sampling lattice configurations. We\ntrain the C-GAN on the dataset consisting of Hybrid Monte Carlo (HMC) samples\nin regions away from the critical region, i.e., in the regions where the HMC\nsimulation cost is not so high. Then we use the trained C-GAN model to generate\nindependent samples in the critical region. Thus, the overall computational\ncost is reduced. We test our approach for Gross-Neveu model in 1+1 dimension.\nWe find that the observable distributions obtained from the proposed C-GAN\nmodel match with those obtained from HMC simulations, while circumventing the\nproblem of critical slowing down.",
        "positive": "\u03b7 and \u03b7' mesons from Nf=2+1+1 twisted mass lattice QCD: We determine mass and mixing angles of eta and eta' states using Nf=2+1+1\nWilson twisted mass lattice QCD. We describe how those flavour singlet states\nneed to be treated in this lattice formulation. Results are presented for three\nvalues of the lattice spacing, a=0.061 fm, a=0.078 fm and a=0.086 fm, with\nlight quark masses corresponding to values of the charged pion mass in a range\nof 230 to 500 MeV and fixed bare strange and charm quark mass values. We obtain\n557(15)(45) MeV for the eta mass (first error statistical, second systematic)\nand 44(5) degrees for the mixing angle in the quark flavour basis,\ncorresponding to -10(5) degrees in the octet-singlet basis."
    },
    {
        "anchor": "The hadronic vacuum polarization contribution to the muon $g-2$ from\n  lattice QCD: We present a calculation of the hadronic vacuum polarization contribution to\nthe muon anomalous magnetic moment, $a_\\mu^{\\mathrm hvp}$, in lattice QCD\nemploying dynamical up and down quarks. We focus on controlling the infrared\nregime of the vacuum polarization function. To this end we employ several\ncomplementary approaches, including Pad\\'e fits, time moments and the\ntime-momentum representation. We correct our results for finite-volume effects\nby combining the Gounaris-Sakurai parameterization of the timelike pion form\nfactor with the L\\\"uscher formalism. On a subset of our ensembles we have\nderived an upper bound on the magnitude of quark-disconnected diagrams and\nfound that they decrease the estimate for $a_\\mu^{\\mathrm hvp}$ by at most 2%.\nOur final result is $a_\\mu^{\\mathrm hvp}=(654\\pm32\\,{}^{+21}_{-23})\\cdot\n10^{-10}$, where the first error is statistical, and the second denotes the\ncombined systematic uncertainty. Based on our findings we discuss the prospects\nfor determining $a_\\mu^{\\mathrm hvp}$ with sub-percent precision.",
        "positive": "A Lattice Study of Renormalons in Asymptotically Free Sigma Models: In general, perturbative expansions of observables in powers of the coupling\nconstant in quantum field theories are asymptotic series. In many cases it is\npossible to apply resummation techniques to assign a unique finite value to an\nasymptotic series, but a particular pattern of divergence, the so-called\nrenormalon, gives rise to non-perturbative ambiguities. The framework of\nNumerical Stochastic Perturbation Theory (NSPT), based on stochastic\nquantisation and the perturbative expansion of lattice fields, makes it\npossible to compute coefficients of perturbative series on the lattice. In this\nwork we report on an NSPT study of asymptotically free sigma models, namely the\nPrincipal Chiral Model and the $\\text{CP}{(N-1)}$ model. We present results for\na lattice computation of the expansion coefficients of the energy density and\ndiscuss signatures of renormalons."
    },
    {
        "anchor": "Topologically Twisted $N=(2,2)$ Supersymmetric Yang-Mills Theory on\n  Arbitrary Discretized Riemann Surface: We define supersymmetric Yang-Mills theory on an arbitrary two-dimensional\nlattice (polygon decomposition) with preserving one supercharge. When a smooth\nRiemann surface $\\Sigma_g$ with genus $g$ emerges as an appropriate continuum\nlimit of the generic lattice, the discretized theory becomes topologically\ntwisted $\\mathcal{N}=(2,2)$ supersymmetric Yang-Mills theory on $\\Sigma_g$. If\nwe adopt the usual square lattice as a special case of the discretization, our\nformulation is identical with Sugino's lattice model. Although the tuning of\nparameters is generally required while taking the continuum limit, the number\nof the necessary parameters is at most two because of the gauge symmetry and\nthe supersymmetry. In particular, we do not need any fine-tuning if we arrange\nthe theory so as to possess an extra global U(1) symmetry ($U(1)_{R}$ symmetry)\nwhich rotates the scalar fields.",
        "positive": "Radius of convergence in lattice QCD at finite $\u03bc_B$ with rooted\n  staggered fermions: In typical statistical mechanical systems the grand canonical partition\nfunction at finite volume is proportional to a polynomial of the fugacity\n$e^{\\mu/T}$. The zero of this Lee-Yang polynomial closest to the origin\ndetermines the radius of convergence of the Taylor expansion of the pressure\naround $\\mu=0$. The computationally cheapest formulation of lattice QCD, rooted\nstaggered fermions, with the usual definition of the rooted determinant, does\nnot admit such a Lee-Yang polynomial. We argue that the radius of convergence\nis then bounded by the spectral gap of the reduced matrix of the unrooted\nstaggered operator. This is a cutoff effect that potentially affects all\nestimates of the radius of convergence with the standard staggered rooting. We\nsuggest a new definition of the rooted staggered determinant at finite chemical\npotential that allows for a definition of a Lee-Yang polynomial, and, therefore\nof the numerical study of Lee-Yang zeros. We also describe an algorithm to\ndetermine the Lee-Yang zeros and apply it to configurations generated with the\n2-stout improved staggered action at $N_t = 4$. We perform a finite-volume\nscaling study of the leading Lee-Yang zeros and estimate the radius of\nconvergence of the Taylor expansion extrapolated to an infinite volume. We show\nthat the limiting singularity is not on the real line, thus giving a lower\nbound on the location of any possible phase transitions at this lattice\nspacing. In the vicinity of the crossover temperature at zero chemical\npotential, the radius of convergence turns out to be $\\mu_B/T \\approx 2$ and\nroughly temperature independent. Our simulations are performed at strange quark\nchemical potential $\\mu_s=0$, but the method can be straightforwardly extended\nto strangeness chemical potential $\\mu_S=0$ or strangeness neutrality."
    },
    {
        "anchor": "Calculation of f_B and the ``Isgur-Wise Function'' using a\n  non-perturbatively improved fermion action: We present a calculation of f_B and of the form factors for the semi-leptonic\ndecay B -> D l nu in the quenched approximation to QCD. Results are generated\non lattices at beta = 6.2, using an O(a)-improved fermion action, with the\nclover coefficient determined non-perturbatively.",
        "positive": "Sum Rules and Cutoff Effects in Wilson Lattice QCD: We use the transfer matrix formalism to derive non-perturbative sum rules in\nWilson's lattice QCD with N_f flavours of quarks. The discretization errors on\nthese identities are treated in detail. As an application, it is shown how the\nsum rules can be exploited to give improved estimates of the continuum spectrum\nand static potential."
    },
    {
        "anchor": "Improved lattice actions: The main strategies to reduce lattice artifacts for spin models, gauge\nfields, free fermions and QCD are discussed.",
        "positive": "The Polyakov Loop and its Relation to Static Quark Potentials and Free\n  Energies: It appears well accepted in the literature that the correlator of Polyakov\nloops in a finite temperature system decays with the \"average\" free energy of\nthe static quark-antiquark system, and can be decomposed into singlet and\nadjoint (or octet for QCD) contributions. By fixing a gauge respecting the\ntransfer matrix, attempts have been made to extract those contributions\nseparately. In this paper we point out that the \"average\" and \"adjoint\"\nchannels of Polyakov loop correlators are misconceptions. We show analytically\nthat all channels receive contributions from singlet states only, and give a\ncorrected definition of the singlet free energy. We verify this finding by\nsimulations of the 3d SU(2) pure gauge theory in the zero temperature limit,\nwhich allows to cleanly extract the ground state exponents and the non-trivial\nmatrix elements. The latter account for the difference between the channels\nobserved in previous simulations."
    },
    {
        "anchor": "Complex-Temperature Singularities in the $d=2$ Ising Model. II.\n  Triangular Lattice: We investigate complex-temperature singularities in the Ising model on the\ntriangular lattice. Extending an earlier analysis of the low-temperature series\nexpansions for the (zero-field) susceptibility $\\bar\\chi$ by Guttmann\n\\cite{g75} to include the use of differential approximants, we obtain further\nevidence in support of his conclusion that the exponent describing the\ndivergence in $\\chi$ at $u=u_e=-1/3$ (where $u = e^{-4K}$) is $\\gamma_e'=5/4$\nand refine his estimate of the critical amplitude. We discuss the remarkable\nnature of this singularity, at which the spontaneous magnetisation diverges\n(with exponent $\\beta_e=-1/8$) and show that it lies at the endpoint of a\nsingular line segment constituting part of the natural boundaries of the free\nenergy in the complex $u$ plane. Using exact results, we find that the specific\nheat has a divergent singularity at $u=-1/3$ with exponent $\\alpha_e'=1$, so\nthat the relation $\\alpha_e'+2\\beta_e+\\gamma_e'=2$ is satisfied. We also study\nthe singularity at $u=u_s=-1$, where $M$ vanishes (with $\\beta_s=3/8$) and $C$\ndiverges logarithmically (with $\\alpha_s' = \\alpha_s = 0$).",
        "positive": "Parton distributions from lattice QCD: We extract the x dependence of the nonsinglet u-d distribution function in\nthe nucleon from the lowest few moments calculated on the lattice, using an\nextrapolation formula which ensures the correct behavior in the chiral and\nheavy quark limits. We discuss the implications for the quark mass dependence\nof meson masses lying on the J(PC)=1(--) Regge trajectory."
    },
    {
        "anchor": "Degenerate distributions in complex Langevin dynamics: one-dimensional\n  QCD at finite chemical potential: We demonstrate analytically that complex Langevin dynamics can solve the sign\nproblem in one-dimensional QCD in the thermodynamic limit. In particular, it is\nshown that the contributions from the complex and highly oscillating spectral\ndensity of the Dirac operator to the chiral condensate are taken into account\ncorrectly. We find an infinite number of classical fixed points of the Langevin\nflow in the thermodynamic limit. The correct solution originates from a\ncontinuum of degenerate distributions in the complexified space.",
        "positive": "Thin Absolute Villains: We perform simulations of an absolute value version of the Villain model on\nphi3 and phi4 Feynman diagrams, ``thin'' 3-regular and 4-regular random graphs.\nThe phi4 results are in excellent quantitative agreement with the exact\ncalculations by Dorey and Kurzepa for an annealed ensemble of thin graphs, in\nspite of simulating only a single graph of each size. We also derive exact\nresults for an annealed ensemble of phi3 graphs and again find excellent\nagreement with the numerical data for single phi3 graphs.\n  The simulations confirm the picture of a mean field vortex transition which\nis suggested by the analytical results. Further simulations on phi5 and phi6\ngraphs and of the standard XY model on phi3 graphs confirm the universality of\nthese results. The calculations of Dorey and Kurzepa were based on\nreinterpreting the large orders behaviour of the anharmonic oscillator in a\nstatistical mechanical context so we also discuss briefly the interpretation of\nsingularities in the large orders behaviour in other models as phase\ntransitions."
    },
    {
        "anchor": "A lattice study of interaction mechanisms in a heavy-light meson-meson\n  system: We study mass spectra of a meson-meson system involving two light and two\nheavy quarks on an anisotropic lattice. The heavy quarks are treated in the\nstatic approximation. The dependence of the spectrum on the relative distance\nof the heavy quarks is extracted from the lattice simulation using the maximum\nentropy method (MEM). A correlation matrix of meson-meson operators emphasizing\nquark and gluon exchange degrees of freedom is employed in an attempt to learn\nabout aspects of mechanisms of hadronic interaction.",
        "positive": "Form factors of two-hadron states from a covariant finite-volume\n  formalism: In this work we develop a Lorentz-covariant version of the previously derived\nformalism for relating finite-volume matrix elements to $\\textbf 2 + \\mathcal J\n\\to \\textbf 2$ transition amplitudes. We also give various details relevant for\nthe implementation of this formalism in a realistic numerical lattice QCD\ncalculation. Particular focus is given to the role of single-particle form\nfactors in disentangling finite-volume effects from the triangle diagram that\narise when $\\mathcal J$ couples to one of the two hadrons. This also leads to a\nnew finite-volume function, denoted $G$, the numerical evaluation of which is\ndescribed in detail. As an example we discuss the determination of the $\\pi \\pi\n+ \\mathcal J \\to \\pi \\pi$ amplitude in the $\\rho$ channel, for which the\nsingle-pion form factor, $F_\\pi(Q^2)$, as well as the scattering phase,\n$\\delta_{\\pi\\pi}$, are required to remove all power-law finite-volume effects.\nThe formalism presented here holds for local currents with arbitrary Lorentz\nstructure, and we give specific examples of insertions with up to two Lorentz\nindices."
    },
    {
        "anchor": "Finite temperature QCD at fixed Q with overlap fermions: We present some preliminary results of the project on finite temperature QCD\nwith overlap fermions at KEK. We performed a series of simulations to assess\nthe effects of fixing the topological sector at finite temperature and we will\nshow the first calculations of topological susceptibility and meson masses for\nquenched and full QCD.",
        "positive": "Quantum chaos and QCD at finite chemical potential: We investigate the distribution of the spacings of adjacent eigenvalues of\nthe lattice Dirac operator. At zero chemical potential $\\mu$, the\nnearest-neighbor spacing distribution $P(s)$ follows the Wigner surmise of\nrandom matrix theory both in the confinement and in the deconfinement phase.\nThis is indicative of quantum chaos. At nonzero chemical potential, the\neigenvalues of the Dirac operator become complex. We discuss how $P(s)$ can be\ndefined in the complex plane. Numerical results from an SU(3) simulation with\nstaggered fermions are compared with predictions from non-hermitian random\nmatrix theory, and agreement with the Ginibre ensemble is found for $\\mu\\approx\n0.7$."
    },
    {
        "anchor": "Hadron Spectroscopy with Dynamical Chirally Improved Fermions: We simulate two dynamical, mass degenerate light quarks on 16^3x32 lattices\nwith a spatial extent of 2.4 fm using the Chirally Improved Dirac operator. The\nsimulation method, the implementation of the action and signals of\nequilibration are discussed in detail. Based on the eigenvalues of the Dirac\noperator we discuss some qualitative features of our approach. Results for\nground state masses of pseudoscalar and vector mesons as well as for the\nnucleon and delta baryons are presented.",
        "positive": "Electromagnetic Form Factors of Excited Nucleons via Parity-Expanded\n  Variational Analysis: Variational analysis techniques in lattice QCD are powerful tools that give\naccess to the excited state spectrum of QCD. At zero momentum, these techniques\nare well established and can cleanly isolate energy eigenstates of either\npositive or negative parity. In order to compute the form factors of a single\nenergy eigenstate, we must perform a variational analysis at non-zero momentum.\nWhen we do this with baryons, we run into issues with parity mixing, as boosted\nbaryons are not eigenstates of parity. The parity-expanded variational analysis\n(PEVA) technique is a novel method for ensuring the successful and consistent\nisolation of boosted baryon eigenstates. This is achieved through a parity\nexpansion of the operator basis used to construct the correlation matrix.\nWorld-first calculations of excited state nucleon form factors using this new\ntechnique are presented, showing the improvement over conventional methods."
    },
    {
        "anchor": "Static $\\bar{Q}Q$ pair free energy and screening masses from correlators\n  of Polyakov loops: continuum extrapolated lattice results at the QCD physical\n  point: We study the correlators of Polyakov loops, and the corresponding gauge\ninvariant free energy of a static quark-antiquark pair in 2+1 flavor QCD at\nfinite temperature. Our simulations were carried out on $N_t$ = 6, 8, 10, 12,\n16 lattices using Symanzik improved gauge action and a stout improved staggered\naction with physical quark masses. The free energies calculated from the\nPolyakov loop correlators are extrapolated to the continuum limit. For the free\nenergies we use a two step renormalization procedure that only uses data at\nfinite temperature. We also measure correlators with definite Euclidean time\nreversal and charge conjugation symmetry to extract two different screening\nmasses, one in the magnetic, and one in the electric sector, to distinguish two\ndifferent correlation lengths in the full Polyakov loop correlator.",
        "positive": "Quenched Chiral Log and Light Quark Mass from Overlap Fermions: We study the quenched chiral behavior of the pion with mass as low as\n$\\approx 180$ MeV. The calculation is done on a quenched lattice of size\n$16^3\\times 28$ and $a = 0.2$ fm with 80 configurations using overlap fermions\nand an improved gauge action. Using an improved constrained curve fitting\ntechnique, we find that the ground state pseudoscalar mass versus bare quark\nmass behavior is well controlled with small statistical errors; this permits a\nreliable fit of the quenched chiral log effects, a determination of the chiral\nlog parameter ($\\delta = 0.26(3)$), and an estimate of the renormalized mass of\nthe light quark ($m^{\\bar{MS}}(\\mu=2 {\\rm GeV}) = 3.7(3) {\\rm MeV}$)."
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory and Gradient Flow in \u03c6^4\n  Theory: In this contribution we present an exploratory study of several novel methods\nfor numerical stochastic perturbation theory. For the investigation we consider\nobservables defined through the gradient flow in the simple {\\phi}^4 theory.",
        "positive": "A construction of chiral fermion action: According to the necessary requirements for a chirally symmetric Dirac\noperator, we present a systematic construction of such operators. We formulate\na criterion for the hermitian operator which enters the construction such that\nthe doubled modes are decoupled even at finite lattice spacing."
    },
    {
        "anchor": "Investigation of the 1+1 dimensional Thirring model using the method of\n  matrix product states: We present preliminary results of a study on the non-thermal phase structure\nof the (1+1) dimensional massive Thirring model, employing the method of matrix\nproduct states. Through investigating the entanglement entropy, the fermion\ncorrelators and the chiral condensate, it is found that this approach enables\nus to observe numerical evidence of a Kosterlitz-Thouless phase transition in\nthe model.",
        "positive": "String breaking in Lattice QCD: The separation of a heavy quark and antiquark pair leads to the formation of\na tube of flux, or string, which should break in the presence of light\nquark-antiquark pairs. This expected zero temperature phenomenon has proven\nelusive in simulations of lattice QCD. We present simulation results that show\nthat the string does break in the confining phase at nonzero temperature."
    },
    {
        "anchor": "Bounds on the Wilson Dirac Operator: New exact upper and lower bounds are derived on the spectrum of the square of\nthe hermitian Wilson Dirac operator. It is hoped that the derivations and the\nresults will be of help in the search for ways to reduce the cost of\nsimulations using the overlap Dirac operator. The bounds also apply to the\nWilson Dirac operator in odd dimensions and are therefore relevant to domain\nwall fermions as well.",
        "positive": "Discretization effects on nucleon root-mean-square radii from lattice\n  QCD at the physical point: We present results for the axial-vector coupling and root-mean-square (RMS)\nradii of the nucleon obtained from 2+1 flavor lattice QCD at the physical point\nwith a large spatial extent of about 10 fm. Our calculations are performed with\nthe PACS10 gauge configurations generated by the PACS Collaboration with the\nsix stout-smeared $O(a)$ improved Wilson-clover quark action and Iwasaki gauge\naction at $\\beta$ = 1.82 and 2.00 corresponding to lattice spacings of 0.085 fm\nand 0.063 fm, respectively. We first evaluate the value of the axial-vector\ncoupling of the nucleon ($g_A$). In addition, the isovector electric, magnetic\nand axial radii and magnetic moment from the corresponding form factors are\nalso determined. Combining the results at $\\beta=1.82$ and $2.00$, we finally\ndiscuss the finite lattice spacing effect. It was found that the effect on\n$g_A$ is kept smaller than the statistical error of 2% while the effect on the\nisovector radii was observed as a possible discretization error of about 10%,\nregardless of the channel."
    },
    {
        "anchor": "Progress towards quantum simulating the classical O(2) model: We connect explicitly the classical $O(2)$ model in 1+1 dimensions, a model\nsharing important features with $U(1)$ lattice gauge theory, to physical models\npotentially implementable on optical lattices and evolving at physical time.\nUsing the tensor renormalization group formulation, we take the time continuum\nlimit and check that finite dimensional projections used in recent proposals\nfor quantum simulators provide controllable approximations of the original\nmodel. We propose two-species Bose-Hubbard models corresponding to these finite\ndimensional projections at strong coupling and discuss their possible\nimplementations on optical lattices using a $^{87}$Rb and $^{41}$K Bose-Bose\nmixture.",
        "positive": "Finite temperature gluon spectral functions from $N_f=2+1+1$ lattice QCD: We investigate gluon spectral functions at finite temperature in Landau\ngauge, based on a subset of lattice QCD ensembles with $N_f=2+1+1$ dynamical\ntwisted mass quarks flavors, generated by the tmfT collaboration. Our study\nuses a novel Bayesian approach for the extraction of non-positive definite\nspectral functions, which for each binned spatial momentum takes into account\nthe gluon correlation functions at all available discrete imaginary\nfrequencies. The spectral functions are extracted at three different lattice\nspacing, where for each of them, a scan of temperatures around the crossover\ntransition is carried out at fixed scale. We find indications for the existence\nof a well defined quasi-particle peak. Due to a relatively small number of\nimaginary frequencies available, we focus on the momentum and temperature\ndependence of the position of this spectral feature. This dispersion relation\nreveals different in-medium masses for longitudinal and transversal gluons at\nhigh temperatures, qualitatively consistent with weak coupling expectations."
    },
    {
        "anchor": "Lattice calculation of $\u03c7_{c0} \\rightarrow 2\u03b3$ decay width: We perform a lattice QCD calculation of the $\\chi_{c0} \\rightarrow 2\\gamma$\ndecay width using a model-independent method which does not require a momentum\nextrapolation of the corresponding off-shell form factors. The simulation is\nperformed on ensembles of $N_f=2$ twisted mass lattice QCD gauge configurations\nwith three different lattice spacings. After a continuum extrapolation, the\ndecay width is obtained to be\n$\\Gamma_{\\gamma\\gamma}(\\chi_{c0})=3.65(83)_{\\mathrm{stat}}(21)_{\\mathrm{lat.syst}}(66)_{\\mathrm{syst}}\\,\n\\textrm{keV}$. Albeit this large statistical error, our result is compatible\nwith the experimental results within 1.3$\\sigma$. Potential improvements of the\nlattice calculation in the future are also discussed.",
        "positive": "The conformal window on the lattice: Lattice simulations can play an important role in the study of dynamical\nelectroweak symmetry breaking by providing quantitative results on the\nnonperturbative dynamics of candidate theories. For this programme to succeed,\nit is crucial to identify the questions that are relevant for phenomenology,\nand develop the tools that will provide robust answers to these questions. The\nexistence of a conformal window for nonsupersymmetric gauge theories, and its\ncharacterization, is one of the phenomenologically important problems that can\nbe studied on the lattice. We summarize the recent results from studies of IR\nfixed points by numerical simulations, discuss their current limitations, and\nanalyze the future perspectives."
    },
    {
        "anchor": "Imaginary chemical potential and finite fermion density on the lattice: Standard lattice fermion algorithms run into the well-known sign problem at\nreal chemical potential. In this paper we investigate the possibility of using\nimaginary chemical potential, and argue that it has advantages over other\nmethods, particularly for probing the physics at finite temperature as well as\ndensity. As a feasibility study, we present numerical results for the partition\nfunction of the two-dimensional Hubbard model with imaginary chemical\npotential.\n  We also note that systems with a net imbalance of isospin may be simulated\nusing a real chemical potential that couples to I_3 without suffering from the\nsign problem.",
        "positive": "Determination of Reference Scales for Wilson Gauge Action from\n  Yang--Mills Gradient Flow: A parametrization of the lattice spacing ($a$) in terms of the bare coupling\n($\\beta$) for the SU(3) Yang--Mills theory with the Wilson gauge action is\ngiven in a wide range of~$\\beta$. The Yang--Mills gradient flow with respect to\nthe flow time~$t$ for the dimensionless observable, $t\\frac{d}{dt}t^2\\langle\nE(t)\\rangle$, is utilized to determine the parametrization. With fine lattice\nspacings ($6.3\\le\\beta\\le7.5$) and large lattice volumes ($N_{\\rm\ns}=64$--$128$), the discretization and finite-volume errors are significantly\nreduced to the same level as the statistical error."
    },
    {
        "anchor": "B_s->D_s/B->D Semileptonic Form-Factor Ratios and Their Application to\n  BR(B^0_s->\u03bc^+\u03bc^-): We calculate form-factor ratios between the semileptonic decays\n\\bar{B}->D^+\\ell^-\\bar{\\nu} and \\bar{B}_s->D_s^+\\ell^-\\bar{\\nu} with lattice\nQCD. These ratios are a key theoretical input in a new strategy to determine\nthe fragmentation fractions of the neutral B decays, which are needed for\nmeasurements of BR(B^0_s-> \\mu^+\\mu^-). We use the MILC ensembles of gauge\nconfigurations with 2+1 flavors of sea quarks at two lattice spacings of\napproximately 0.12 fm and 0.09 fm. We use the model-independent\nz-parametrization to extrapolate our simulation results at small recoil toward\nmaximum recoil. Our results for the form-factor ratios are\n$f_0^{(s)}(M^2_\\pi)/f_0^{(d)}(M^2_K) =1.046(44)_{stat.}(15)_{syst.}$ and\n$f_0^{(s)}(M^2_\\pi)/f_0^{(d)}(M^2_\\pi)=1.054(47)_{stat.}(17)_{syst.}$. In\ncontrast to a QCD sum-rule calculation, no significant departure from U-spin\n(d<->s) symmetry is observed.",
        "positive": "Theta vacuum physics from QCD at fixed topology: We propose a method to obtain physical quantities in the theta vacuum from\nthose at fixed topology, which are different by finite size effects. Extending\nthe work by Brower et al., we derive the formula to estimate these finite size\ncorrections for arbitrary correlators in terms of the topological\nsusceptibility and the theta dependence. Applying this formula, we show that\ntopological susceptibility can be measured through two-point functions of\npseudoscalar operator."
    },
    {
        "anchor": "Decay width of light quark hybrid meson from the lattice: Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the\nspectrum and decay of a $J^{PC}=1^{-+}$ spin-exotic hybrid meson.\n  We test lattice determination of S-wave decay amplitudes at threshold using\n$b_1 \\to \\pi \\omega$ where agreement with data is found. We find a hybrid meson\nstate at 2.2(2) GeV with a partial width to $\\pi b_1$ of 400(120) MeV and to\n$\\pi f_1$ of 90(60) MeV.",
        "positive": "Quark anti-quark expectation value in finite volume: We have computed the quark anti-quark expectation value in finite volume at\ntwo loop in chiral perturbation theory and compare it with a formula obtained\nin analogy to the Luscher formula for pion mass in finite volume. We observe\nthat due to the small finite size correction at two loop it is not possible to\nobtain conclusions on the accuracy of the extended Luscher formula."
    },
    {
        "anchor": "Study of doubly heavy tetraquarks in Lattice QCD: We present results of a lattice calculation of tetraquark states with quark\ncontents $q_1q_2\\bar{Q}\\bar{Q}, \\, q_1,q_2 \\subset u,d,s,c$ and $Q \\equiv b,c$\nin both spin zero ($J=0$) and spin one ($J=1$) sectors. These calculations are\nperformed on three dynamical $N_f = 2 + 1 + 1$ highly improved staggered quark\nensembles at lattice spacings of about 0.12, 0.09 and 0.06 fm. We use the\noverlap action for light to charm quarks while a non-relativistic action with\nnon-perturbatively improved coefficients with terms up to $\\mathcal{O}(\\alpha_s\nv^4)$ is employed for the bottom quark. While considering two heavy quarks as\ncharm or bottom, we calculate the energy levels of various four-quark\nconfigurations with light quark masses ranging from the physical strange quark\nmass to that of the corresponding physical pion mass. Results for the spin one\nstates show the presence of ground state energy levels which are below their\nrespective thresholds for all the light flavor combinations with both doubly\nheavy quarks and particularly for the bottom quarks. Further, we identify a\ntrend that the energy splittings, defined as the energy difference between the\nground state energy levels and their respective thresholds, increase with\ndecreasing the light quark masses and are maximum at the physical point for all\nthe spin one states. The rate of increase is however dependent on the light\nquark configuration of the particular spin one state. We also present a study\nof hadron mass relations involving tetraquarks, baryons and mesons arising in\nthe limit of infinitely heavy quark and find that these relations are more\ncompatible with the heavy quark limit in the bottom sector but deviate\nsubstantially in the charm sector. The ground state spectra of the spin zero\ntetraquark states with various flavor combinations are seen to lie above their\nrespective thresholds.",
        "positive": "Estimating the thermal photon production rate using lattice QCD: We present results for the photon emission rate determined from the\ntransverse channel vector correlator at fixed spatial momentum using two\nflavors of dynamical Wilson fermions at $T\\sim$250 MeV. We estimate the\ntransverse channel spectral function using the continuum extrapolated\ncorrelator by applying various fit ans\\\"atze with a smooth matching to the NLO\nperturbative result. We confront our estimate based on this channel with the\nlatest results of our collaboration based on the difference of the transverse\nand longitudinal channels."
    },
    {
        "anchor": "Speeding up the Hybrid-Monte-Carlo algorithm for dynamical fermions: We propose a modification of the Hybrid-Monte-Carlo algorithm that allows for\na larger step-size of the integration scheme at constant acceptance rate. The\nkey ingredient is that the pseudo-fermion action is split into two parts. We\ntest our proposal at the example of the two-dimensional lattice Schwinger model\nwith two degenerate flavours of Wilson-fermions.",
        "positive": "Determination of SU(2) ChPT LECs from 2+1 flavor staggered lattice\n  simulations: By fitting pion masses and decay constants from 2+1 flavor staggered lattice\nsimulations to the predictions of NLO and NNLO SU(2) chiral perturbation theory\nwe determine the low-energy constants l_3 and l_4. The lattice ensembles were\ngenerated by the Wuppertal-Budapest collaboration and cover pion masses in the\nrange of 135 to 435 MeV and lattice scales between 0.7 and 2.0 GeV. By choosing\na suitable scaling trajectory, we were able to demonstrate that precise and\nstable results for the LECs can be obtained from continuum ChPT to NLO. The\npion masses available in this work also allow us to study the applicability of\nusing ChPT to extrapolate from higher masses to the physical pion mass."
    },
    {
        "anchor": "The unreasonable effectiveness of effective string theory: the case of\n  the 3d SU(2) Higgs model: We study string breaking in the three dimensional SU(2) Higgs model, using\nvalues of the gauge coupling for which the confinement-like and Higgs-like\nregions of the phase diagram are separated just by a smooth crossover. We show\nthat even in the presence of string breaking, the confining part of the\ninterquark potential is well described by the Effective String Theory and that\nalso the fine details of the effective string, like the higher order terms of\nthe Nambu-Goto action or the boundary correction, can be precisely extracted\nfrom the fits and agree with the effective string predictions. We comment on\nthe implications of these results for QCD simulations with dynamical quarks.",
        "positive": "QCD correlation functions and instantons: QCD point-to-point correlation functions at distances .2-1 fm are very\ndifferent for different channels, and they tell us a lot about inter-quark\ninteractions. Recent studies based on experimental data, 'instanton liquid'\napproach and lattice measurements are reviewed. Agreement between all of them\nshow that instanton-induced forces dominate the light quark physics, and new\nfindings by Negele et al, that {\\it hadrons survive 'cooling'}, make this\nstatement obvious. We also argue that {\\it chiral symmetery restoration} is due\nto breaking of the 'instanton liquid' into {\\it polarized} 'instanton\nmolecules'. % For Lattice-93 proceedings, figures and % hard copies available\nat request, sorry."
    },
    {
        "anchor": "Evolution of Parton Distribution Functions in the Short-Distance\n  Factorization Scheme: Lattice QCD offers the possibility of computing parton distributions from\nfirst principles, although not in the usual $\\overline{MS}$ factorization\nscheme. We study in this paper the evolution of non-singlet parton distribution\nfunctions (PDFs) in the short-distance factorization scheme which notably\narises in lattice calculations in the pseudo-distribution approach. We provide\nan assessment of non-perturbative evolution of PDFs from already published\nlattice matrix elements, and show how this evolution can be used to reduce the\nfluctuation of the lattice data. We compare our result with expectations\nobtained thanks to a perturbative matching to $\\overline{MS}$. By highlighting\nthe limitations of the current computations, we advocate for a new strategy\nusing lattice calculations in small volume.",
        "positive": "One-loop renormalisation of quark bilinears for overlap fermions with\n  improved gauge actions: We compute lattice renormalisation constants of local bilinear quark\noperators for overlap fermions and improved gauge actions. Among the actions we\nconsider are the Symanzik, L\\\"uscher-Weisz, Iwasaki and DBW2 gauge actions. The\nresults are given for a variety of $\\rho$ parameters. We show how to apply mean\nfield (tadpole) improvement to overlap fermions. The question, what is a good\ngauge action, is discussed from the perturbative point of view. Finally, we\nshow analytically that the gauge dependent part of the self-energy and the\namputated Green functions are independent of the lattice fermion\nrepresentation, using either Wilson or overlap fermions."
    },
    {
        "anchor": "Lattice Wess-Zumino model with Ginsparg-Wilson fermions: One-loop\n  results and GPU benchmarks: We numerically evaluate the one-loop counterterms for the four-dimensional\nWess-Zumino model formulated on the lattice using Ginsparg-Wilson fermions of\nthe overlap (Neuberger) variety, together with an auxiliary fermion (plus\nsuperpartners), such that a lattice version of $U(1)_R$ symmetry is exactly\npreserved in the limit of vanishing bare mass. We confirm previous findings by\nother authors that at one loop there is no renormalization of the\nsuperpotential in the lattice theory, but that there is a mismatch in the\nwavefunction renormalization of the auxiliary field. We study the range of the\nDirac operator that results when the auxiliary fermion is integrated out, and\nshow that localization does occur, but that it is less pronounced than the\nexponential localization of the overlap operator. We also present preliminary\nsimulation results for this model, and outline a strategy for nonperturbative\nimprovement of the lattice supercurrent through measurements of supersymmetry\nWard identities. Related to this, some benchmarks for our graphics processing\nunit code are provided. Our simulation results find a nearly vanishing vacuum\nexpectation value for the auxiliary field, consistent with approximate\nsupersymmetry at weak coupling.",
        "positive": "Hierarchically deflated conjugate gradient: We present a multi-level algorithm for the solution of five dimensional\nchiral fermion formulations, including domain wall and Mobius Fermions. The\nalgorithm operates on the red-black preconditioned Hermitian operator, and\ndirectly accelerates conjugate gradients on the normal equations. The coarse\ngrid representation of this matrix is next-to-next-to-next-to-nearest neighbour\nand multiple algorithmic advances are introduced, which help minimise the\noverhead of the coarse grid. The treatment of the coarse grids is purely four\ndimensional, and the bulk of the coarse grid operations are nearest neighbour.\nThe intrinsic cost of most of the coarse grid operations is therefore\ncomparable to those for the Wilson case. We also document the implementation of\nthis algorithm in the BAGEL/Bfm software package and report on the measured\nperformance gains the algorithm brings to simulations at the physical point on\nIBM BlueGene/Q hardware."
    },
    {
        "anchor": "Confinement from Center Vortices: A review of old and new results: I briefly review the numerical evidence, some old and some quite recent, in\nfavor of the center vortex theory of confinement.",
        "positive": "Eigenvalue density of Wilson loops in 2D SU(N) YM: In 1981 Durhuus and Olesen (DO) showed that at infinite N the eigenvalue\ndensity of a Wilson loop matrix W associated with a simple loop in\ntwo-dimensional Euclidean SU(N) Yang-Mills theory undergoes a phase transition\nat a critical size. The averages of det(z-W), 1/det(z-W), and det(1+uW)/(1-vW)\nat finite N lead to three different smoothed out expressions, all tending to\nthe DO singular result at infinite N. These smooth extensions are obtained and\ncompared to each other."
    },
    {
        "anchor": "Comparative Study of full QCD Hadron Spectrum and Static Quark Potential\n  with Improved Actions: We investigate effects of action improvement on the light hadron spectrum and\nthe static quark potential in two-flavor QCD for $a^{-1} \\approx 1$ GeV and\n$m_{PS}/m_V = 0.7-0.9$. We compare a renormalization group improved action with\nthe plaquette action for gluons, and the SW-clover action with the Wilson\naction for quarks. We find a significant improvement in the hadron spectrum by\nimproving the quark action, while the gluon improvement is crucial for a\nrotationally invariant static potential. We also explore the region of light\nquark masses corresponding to $m_{PS}/m_V \\geq 0.4$ on a 2.7 fm lattice using\nthe improved gauge and quark action. A flattening of the potential is not\nobserved up to 2 fm.",
        "positive": "Anomalous superfluidity in 2+1 dimensional two-color lattice QCD: We study thermodynamics of strongly coupled lattice QCD with $two$ colors of\nstaggered fermions in $(2+1)$ dimensions. The partition function of this model\ncan be written elegantly as a statistical mechanics of dimers and baryonloops.\nThe model is invariant under an $SO(3)\\times U(1)$ symmetry. At low\ntemperatures we find evidence for superfluidity in the U(1) symmetry sector\nwhile the SO(3) symmetry remains unbroken. The finite temperature phase\ntransition appears to belong to the Kosterlitz-Thouless universality class, but\nthe superfluid density jump $\\rho_s(T_c)$ at the critical temperature $T_c$ is\nanomalously higher than the normal value of $2 T_c/\\pi$. We show that by adding\na small SO(3) symmetry breaking term to the model, the superfluid density jump\nreturns to its normal value implying that the extra symmetry causes anomalous\nsuperfluid behavior. Our results may be of interest to researchers studying\nsuperfluidity in spin-1 systems."
    },
    {
        "anchor": "Simulation of an ensemble of $N_f=2+1+1$ twisted mass clover-improved\n  fermions at physical quark masses: We present a general strategy aimed at generating $N_f=2+1+1$ configurations\nwith quarks at their physical mass using maximally twisted mass fermions to\nensure automatic $O(a)$ improvement, in the presence of a clover term tuned to\nreduce the charged to neutral pion mass difference. The target system, for the\nmoment, is a lattice of size $64^3 \\times 128$ with a lattice spacing $a\\sim\n0.08$ fm. We show preliminary results on the pion and kaon mass and decay\nconstants.",
        "positive": "The 2n-point renormalized coupling constants in the 3d Ising model:\n  estimates by high temperature series to order beta^17: We compute the 2n-point renormalized coupling constants in the symmetric\nphase of the 3d Ising model on the sc lattice in terms of the high temperature\nexpansions O(beta^{17}) of the Fourier transformed 2n-point connected\ncorrelation functions at zero momentum. Our high temperature estimates of these\nquantities, which enter into the small field expansion of the effective\npotential for a 3d scalar field at the IR fixed point or, equivalently, in the\ncritical equation of state of the 3d Ising model universality class, are\ncompared with recent results obtained by renormalization group methods, strong\ncoupling, stochastic simulations as well as previous high temperature\nexpansions."
    },
    {
        "anchor": "Staggered chiral perturbation theory in the two-flavor case: I study two-flavor staggered chiral perturbation theory in the light\npseudoscalar sector. The pion mass and decay constant are calculated through\nNLO in the partially-quenched case. In the limit where the strange quark mass\nis large compared to the light quark masses and the taste splittings, I show\nthat the SU(2) staggered chiral theory emerges from the SU(3) staggered chiral\ntheory, as expected. Explicit relations between SU(2) and SU(3) low energy\nconstants and taste-violating parameters are given. The results are useful for\nSU(2) chiral fits to asqtad data and allow one to incorporate effects from\nvarying strange quark masses.",
        "positive": "Static hybrid quarkonium potential with improved staggered quarks: We are studying the effects of light dynamical quarks on the excitation\nenergies of a flux tube between a static quark and antiquark. We report\npreliminary results of an analysis of the ground state potential and the\n$\\Sigma^{\\prime+}_g$ and $\\Pi_u$ potentials. We have measured these potentials\non closely matched ensembles of gauge configurations, generated in the quenched\napproximation and with 2+1 flavors of Asqtad improved staggered quarks."
    },
    {
        "anchor": "Systematic errors due to linear congruential random-number generators\n  with the Swendsen-Wang algorithm: A warning: We show that linear congruential pseudo-random-number generators can cause\nsystematic errors in Monte Carlo simulations using the Swendsen-Wang algorithm,\nif the lattice size is a multiple of a very large power of 2 and one random\nnumber is used per bond. These systematic errors arise from correlations within\na single bond-update half-sweep. The errors can be eliminated (or at least\nradically reduced) by updating the bonds in a random order or in an aperiodic\nmanner. It also helps to use a generator of large modulus (e.g. 60 or more\nbits).",
        "positive": "Exploring non-Abelian gauge theory with energy-momentum tensor; stress,\n  thermodynamics and correlations: We perform various lattice numerical analyses with the energy-momentum tensor\n(EMT) defined through the gradient flow. We explore the spatial distribution of\nthe stress tensor in static quark-anti-quark systems and thermodynamic\nquantities at nonzero temperature, as well as the correlation functions of EMT.\nThe stress tensor distribution is also studied in the Abelian-Higgs model,\nwhich is compared with the lattice result."
    },
    {
        "anchor": "Multicanonical Multigrid Monte Carlo: To further improve the performance of Monte Carlo simulations of first-order\nphase transitions we propose to combine the multicanonical approach with\nmultigrid techniques. We report tests of this proposition for the\n$d$-dimensional $\\Phi^4$ field theory in two different situations. First, we\nstudy quantum tunneling for $d = 1$ in the continuum limit, and second, we\ninvestigate first-order phase transitions for $d = 2$ in the infinite volume\nlimit. Compared with standard multicanonical simulations we obtain improvement\nfactors of several resp. of about one order of magnitude.",
        "positive": "Advanced Linked Cluster Expansion. Scalar Fields at Finite Temperature: Linked cluster expansions provide a useful tool for both analytical and\nnumerical investigations of lattice field theories. The expansion parameter(s)\nbeing the interaction strength(s) fields at neighboured lattice sites are\ncoupled, they result into convergent hopping parameter like series for free\nenergies, correlation functions and in particular susceptibilities. We consider\nscalar fields with O(N) symmetric nearest neighbour interactions on hypercubic\nlattices with possibly finite extension in some directions, thus including\nfield theories at finite temperature T. We improve known and develop new\ntechniques and algorithms to increase the order n the expansions can be\ncomputed to in such a way that detailed information on critical behaviour can\nbe extracted from the susceptibility series. This concerns both simple moments\nas well as higher correlations such as 4- and 6-point functions used to define\nrenormalized coupling constants. Particular emphasis is done on finite\ntemperature field theory. In order to be able to measure finite T critical\nbehaviour, the order of explicit computation n has to be sufficiently large\ncompared to 1/T in lattice units. 2- and 4-point susc. series are computed up\nto and including the 18th order and beyond."
    },
    {
        "anchor": "Charge Symmetry Violation in the Electromagnetic Form Factors of the\n  Proton: Experimental tests of QCD through its predictions for the strange-quark\ncontent of the proton have been drastically restricted by our lack of knowledge\nof the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the\nproton's electromagnetic form factors by performing the first extraction of\nthese quantities based on an analysis of lattice QCD data. The resulting values\nare an order of magnitude smaller than current bounds on proton strangeness\nfrom parity violating electron-proton scattering experiments. This result paves\nthe way for a new generation of experimental measurements of the proton's\nstrange form factors to challenge the predictions of QCD.",
        "positive": "Physical and cut-off effects of heavy sea quarks: We simulate a theory with two dynamical O($a$) improved Wilson quarks whose\nmass $M$ ranges from a factor eight up to a factor two below the charm quark\nmass and at three values of the lattice spacing ranging from 0.066 to 0.034 fm.\nThis theory is a prototype to study the decoupling of heavy quarks. We measure\nthe mass and cut-off dependence of ratios of gluonic observables defined from\nthe Wilson flow or the static potential. The size of the 1/$M$ corrections can\nbe determined and disentangled from the lattice artifacts. The difference with\nthe pure gauge theory is at the percent level when two quarks with a mass of\nthe charm quark are present."
    },
    {
        "anchor": "Lattice determinations of the strong coupling: Lattice QCD has reached a mature status. State of the art lattice\ncomputations include $u,d,s$ (and even the $c$) sea quark effects, together\nwith an estimate of electromagnetic and isospin breaking corrections for\nhadronic observables. This precise and first principles description of the\nstandard model at low energies allows the determination of multiple quantities\nthat are essential inputs for phenomenology and not accessible to perturbation\ntheory.\n  One of the fundamental parameters that are determined from simulations of\nlattice QCD is the strong coupling constant, which plays a central role in the\nquest for precision at the LHC. Lattice calculations currently provide its best\ndeterminations, and will play a central role in future phenomenological\nstudies. For this reason we believe that it is timely to provide a pedagogical\nintroduction to the lattice determinations of the strong coupling. Rather than\nanalysing individual studies, the emphasis will be on the methodologies and the\nsystematic errors that arise in these determinations. We hope that these notes\nwill help lattice practitioners, and QCD phenomenologists at large, by\nproviding a self-contained introduction to the methodology and the possible\nsources of systematic error.\n  The limiting factors in the determination of the strong coupling turn out to\nbe different from the ones that limit other lattice precision observables. We\nhope to collect enough information here to allow the reader to appreciate the\nchallenges that arise in order to improve further our knowledge of a quantity\nthat is crucial for LHC phenomenology.",
        "positive": "Topology and Confinement in SU(N) Gauge Theories: The large N limit of SU(N) gauge theories in 3+1 dimensions is investigated\non the lattice by extrapolating results obtained for $2 \\le N \\le 5$. A\nnumerical determination of the masses of the lowest-lying glueball states and\nof the topological susceptibility in the limit $N\\to\\infty$ is provided. Ratios\nof the tensions of stable k-strings over the tension of the fundamental string\nare investigated in various regimes and the results are compared with\nexpectations based on several scenarios -- in particular MQCD and Casimir\nscaling. While not conclusive at zero temperature in D=3+1, in the other cases\ninvestigated our data seem to favour the latter."
    },
    {
        "anchor": "What are the Confining Field Configurations of Strong-Coupling Lattice\n  Gauge Theory?: Starting from the strong-coupling SU(2) Wilson action in D=3 dimensions, we\nderive an effective, semi-local action on a lattice of spacing L times the\nspacing of the original lattice. It is shown that beyond the adjoint\ncolor-screening distance, i.e. for $L \\ge 5$, thin center vortices are stable\nsaddlepoints of the corresponding effective action. Since the entropy of these\nstable objects exceeds their energy, center vortices percolate throughout the\nlattice, and confine color charge in half-integer representations of the SU(2)\ngauge group. This result contradicts the folklore that confinement in\nstrong-coupling lattice gauge theory, for D>2 dimensions, is simply due to\nplaquette disorder, as is the case in D=2 dimensions. It also demonstrates\nexplicitly how the emergence and stability of center vortices is related to the\nexistence of color screening by gluon fields.",
        "positive": "Solution to new sign problems with Hamiltonian Lattice Fermions: We present a solution to the sign problem in a class of particle-hole\nsymmetric Hamiltonian lattice fermion models on bipartite lattices using the\nidea of fermion bags. The solution remains valid when the particle-hole\nsymmetry is broken through a staggered chemical potential term. This solution\nallows, for the first time, simulations of some massless four-fermion models\nwith minimal fermion doubling and with an odd number of fermion flavors using\nultra-local actions. One can thus study a variety of quantum phase transitions\nthat have remained unexplored so far due to sign problems."
    },
    {
        "anchor": "The QCD axion beyond the classical level: A lattice study: The axion is a hypothetical elementary particle postulated by the\nPeccei-Quinn theory to resolve the strong CP problem in QCD. If axions exist\nand have low mass, they are a candidate for dark matter as well. So far our\nknowledge of the properties of the QCD axion rests on semi-classical arguments\nand effective theory. In this work we perform, for the first time, a fully\ndynamical investigation of the Peccei-Quinn theory, focussing on the axion\nmass, by simulating the theory on the lattice. The results of the simulation\nare found to be in conflict with present axion phenomenology.",
        "positive": "A partially quenched analysis of the eta-eta' system in N_f=2 QCD: We report on a first, comprehensive partially quenched study of the eta-eta'\nproblem, based on SESAM configurations on a 16^3x32 lattice at beta=5.6 QCD\nwith two (mass degenerate) active sea quark flavours. By means of the spectral\napproximation of the two-loop (hairpin) diagrams, we find clear plateau\nformation in the effective masses which enables us both to determine the\neta-eta' mass matrix and the alpha-parameter in the effective chiral Lagrangian\nfor the flavour singlet sector, alpha=0.028 +- 0.013."
    },
    {
        "anchor": "$|V_{cd}|$ and $|V_{cs}|$ from Semileptonic and Leptonic decays using\n  lattice QCD methods: In this paper, we review recent calculations of the CKM matrix elements\n$|V_{cd}|$ and $|V_{cs}|$ from semileptonic and leptonic decays of $D$ and\n$D_s$ mesons using lattice QCD methods.",
        "positive": "A theorem concerning twisted and untwisted partition functions in U(N)\n  and SU(N) lattice gauge theories: In order to get a clue to understanding the volume-dependence of vortex free\nenergy (which is defined as the ratio of the twisted against the untwisted\npartition function), we investigate the relation between vortex free energies\ndefined on lattices of different sizes. An equality is derived through a simple\ncalculation which equates a general linear combination of vortex free energies\ndefined on a lattice to that on a smaller lattice. The couplings in the\ndenominator and in the numerator however shows a discrepancy, and we argue that\nit vanishes in the thermodynamic limit. Comparison between our result and the\nwork of Tomboulis is also presented. In the appendix we carefully examine the\nproof of quark confinement by Tomboulis and summarize its loopholes."
    },
    {
        "anchor": "QCD at non-zero temperature and density from the lattice: The study of systems as diverse as the cores of neutron stars and heavy-ion\ncollision experiments requires the understanding of the phase structure of QCD\nat non-zero temperature, T, and chemical potential, mu_q. We review some of the\ndifficulties of performing lattice simulations of QCD with non-zero mu_q, and\noutline the re-weighting method used to overcome this problem. This method is\nused to determine the critical endpoint of QCD in the (mu_q,T) plane. We study\nthe pressure and quark number susceptibility at small mu_q.",
        "positive": "Nonstandard Cutoff Effects in the Nonlinear Sigma Model: High precision measurements of the renormalized zero-momentum 4-point\ncoupling g_R and of the Luscher-Weisz-Wolff running coupling gbar(L) = L*m(L)\nperformed with two different lattice actions in the non-perturbative region\nconfirm the earlier observations, that the cutoff effects look linear, in\ncontrast to perturbative considerations. The use of different actions allows\none to make a more reliable estimate on the continuum limit. The measurements\nwere done for infinite volume correlation length up to 350."
    },
    {
        "anchor": "In-medium hadron properties from lattice QCD: I review recent results from lattice QCD calculations on the in-medium hadron\nproperties. I discuss the thermal dilepton rates, heavy quarkonium properties\nas well as the chiral and $U(1)_A$ symmetries at finite temperature.",
        "positive": "On the price of light quarks: The computational cost of numerical simulations of QCD with light dynamical\nWilson-quarks is estimated. The qualitative behaviour of the pion mass and\ncoupling at small quark masses is discussed."
    },
    {
        "anchor": "Chiral Loops and Ghost States in the Quenched Scalar Propagator: The scalar, isovector meson propagator is analyzed in quenched QCD, using the\nMQA pole-shifting ansatz to study the chiral limit. In addition to the expected\nshort-range exponential falloff characteristic of a heavy scalar meson, the\npropagator also exhibits a longer-range, negative metric contribution which\nbecomes pronounced for smaller quark masses. We show that this is a quenched\nchiral loop effect associated with the anomalous structure of the $\\eta '$\npropagator in quenched QCD. Both the time dependence and the quark mass\ndependence of this effect are well-described by a chiral loop diagram\ncorresponding to an $\\eta '- \\pi$ intermediate state, which is light and\neffectively of negative norm in the quenched approximation. The relevant\nparameters of the effective Lagrangian describing the scalar sector of the\nquenched theory are determined.",
        "positive": "Quark and gluon momentum fractions in the pion from $N_f=2+1+1$ lattice\n  QCD: We perform the first full decomposition of the pion momentum into its gluon\nand quark contributions. We employ an ensemble generated by the Extended\nTwisted Mass Collaboration with $N_f=2 + 1 +1$ Wilson twisted mass clover\nfermions at maximal twist tuned to reproduce the physical pion mass. We present\nour results in the $\\overline{\\mathrm{MS}}$ scheme at $2\\gev$. We find\n$\\avgx_{u+d}=0.601(28)$, $\\avgx_s=0.059(13)$, $\\avgx_c=0.019(05)$, and\n$\\avgx_g=0.52(11)$ for the separate contributions, respectively, whose sum\nsaturates the momentum sum rule."
    },
    {
        "anchor": "Quenched Lattice QCD with Domain Wall Fermions and the Chiral Limit: Quenched QCD simulations on three volumes, $8^3 \\times$, $12^3 \\times$ and\n$16^3 \\times 32$ and three couplings, $\\beta=5.7$, 5.85 and 6.0 using domain\nwall fermions provide a consistent picture of quenched QCD. We demonstrate that\nthe small induced effects of chiral symmetry breaking inherent in this\nformulation can be described by a residual mass ($\\mres$) whose size decreases\nas the separation between the domain walls ($L_s$) is increased. However, at\nstronger couplings much larger values of $L_s$ are required to achieve a given\nphysical value of $\\mres$. For $\\beta=6.0$ and $L_s=16$, we find\n$\\mres/m_s=0.033(3)$, while for $\\beta=5.7$, and $L_s=48$,\n$\\mres/m_s=0.074(5)$, where $m_s$ is the strange quark mass. These values are\nsignificantly smaller than those obtained from a more naive determination in\nour earlier studies. Important effects of topological near zero modes which\nshould afflict an accurate quenched calculation are easily visible in both the\nchiral condensate and the pion propagator. These effects can be controlled by\nworking at an appropriately large volume. A non-linear behavior of $m_\\pi^2$ in\nthe limit of small quark mass suggests the presence of additional infrared\nsubtlety in the quenched approximation. Good scaling is seen both in masses and\nin $f_\\pi$ over our entire range, with inverse lattice spacing varying between\n1 and 2 GeV.",
        "positive": "Thermal Simulations, Open Boundary Conditions and Switches: $SU(N)$ gauge theories on compact spaces have a non-trivial vacuum structure\ncharacterized by a countable set of topological sectors and their topological\ncharge. In lattice simulations, every topological sector needs to be explored a\nnumber of times which reflects its weight in the path integral. Current lattice\nsimulations are impeded by the so-called freezing of the topological charge\nproblem. As the continuum is approached, energy barriers between topological\nsectors become well defined and the simulations get trapped in a given sector.\nA possible way out was introduced by L\\\"uscher and Schaefer using open boundary\ncondition in the time extent. However, this solution cannot be used for thermal\nsimulations, where the time direction is required to be periodic. In this\nproceedings, we present results obtained using open boundary conditions in\nspace, at non-zero temperature. With these conditions, the topological charge\nis not quantized and the topological barriers are lifted. A downside of this\nmethod are the strong finite-size effects introduced by the boundary\nconditions. We also present some exploratory results which show how these\nconditions could be used on an algorithmic level to reshuffle the system and\ngenerate periodic configurations with non-zero topological charge."
    },
    {
        "anchor": "Remark on the energy-momentum tensor in the lattice formulation of 4D\n  $\\mathcal{N}=1$ SYM: In a recent paper, arXiv:1209.2473 \\cite{Suzuki:2012gi}, we presented a\npossible definition of the energy-momentum tensor in the lattice formulation of\nthe four-dimensional $\\mathcal{N}=1$ supersymmetric Yang--Mills theory, that is\nconserved in the quantum continuum limit. In the present Letter, we propose a\nquite similar but somewhat different definition of the energy-momentum tensor\n(that is also conserved in the continuum limit) which is superior in several\naspects: In the continuum limit, the origin of the energy automatically becomes\nconsistent with the supersymmetry and the number of renormalization constants\nthat require a (non-perturbative) determination is reduced to two from four,\nthe number of renormalization constants appearing in the construction in Ref.\n\\cite{Suzuki:2012gi}.",
        "positive": "$O(a)$ Improvement for Quenched Wilson Fermions: We briefly describe some of our recent results for the mass spectrum and\nmatrix elements using $O(a)$ improved fermions for quenched QCD. Where possible\na comparison is made between improved and Wilson fermions."
    },
    {
        "anchor": "Dual Formulation and Phase Diagram of Lattice QCD in the Strong Coupling\n  Regime: We present the computation of invariants that arise in the strong coupling\nexpansion of lattice QCD. These invariants are needed for Monte Carlo\nsimulations of Lattice QCD with staggered fermions in a dual, color singlet\nrepresentation. This formulation is in particular useful to tame the finite\ndensity sign problem. The gauge integrals in this limiting case\n$\\beta\\rightarrow 0$ are well known, but the gauge integrals needed to study\nthe gauge corrections are more involved. We discuss a method to evaluate such\nintegrals.\n  The phase boundary of lattice QCD for staggered fermions in the $\\mu_B-T$\nplane has been established in the strong coupling limit. We present numerical\nsimulations away from the strong coupling limit, taking into account the higher\norder gauge corrections via plaquette occupation numbers. This allows to study\nthe nuclear and chiral transition as a function of $\\beta$.",
        "positive": "Excited states in the full QCD hadron spectrum on a $16^3 \\times 40$\n  lattice: We report the hadron mass spectrum obtained on a $16^3 \\times 40$ lattice at\n$\\beta = 5.7$ using two flavors of staggered fermions with $m a = 0.01$. We\ncalculate the masses of excited states that have the same quantum numbers as\nthe $\\pi$, $\\rho$ and $N$. They are obtained by a combined analysis of the\nhadron correlators from sources of size $16^3$ and $8^3$. We also report on the\nhadron spectrum for a wide range of valence quark masses."
    },
    {
        "anchor": "Progress in Kaon Physics on the Lattice: We review recent progress in calculating kaon spectrum, pseudoscalar meson\ndecay constants, $B_K$, $\\epsilon'/\\epsilon$, $K\\to \\pi\\pi$ matrix elements,\nkaon semileptonic form factors, and moments of kaon distribution amplitudes on\nthe lattice. We also address the issue of how best to improve the staggered\nfermion formulation for the action and operators.",
        "positive": "The Hierarchical $\u03c6^4$ - Trajectory by Perturbation Theory in a\n  Running Coupling and its Logarithm: We compute the hierarchical $\\phi^4$-trajectory in terms of perturbation\ntheory in a running coupling. In the three dimensional case we resolve a\nsingularity due to resonance of power counting factors in terms of logarithms\nof the running coupling. Numerical data is presented and the limits of validity\nexplored. We also compute moving eigenvalues and eigenvectors on the trajectory\nas well as their fusion rules."
    },
    {
        "anchor": "Low energy scattering parameters from the solutions of the\n  non-relativistic Yukawa model on a 3-dimensional lattice: The numerical solutions of the non-relativistic Yukawa model on a\n3-dimensional size lattice with periodic boundary conditions are obtained. The\npossibility to extract the corresponding -- infinite space -- low energy\nparameters and bound state binding energies from eigensates computed at finite\nlattice size is discussed.",
        "positive": "Nucleon form factors and structure functions: We give an update on our ongoing efforts to compute the nucleon's form\nfactors and moments of structure functions using Nf=2 flavours of\nnon-perturbatively improved Clover fermions. We focus on new results obtained\non gauge configurations where the pseudo-scalar meson mass is in the range of\n170-270 MeV. We will compare our results with various estimates obtained from\nchiral effective theories since we have some overlap with the quark mass region\nwhere results from such theories are believed to be applicable."
    },
    {
        "anchor": "Lattice QCD and the two-photon decay of the neutral pion: Two-photon decays probe the structure of mesons and represent an important\ncontribution to hadronic light-by-light scattering. For the neutral pion, the\ndecay amplitude tests the effects of the chiral anomaly; for a heavy quarkonium\nstate, it measures the magnitude of its wavefunction at the origin. We rederive\nthe expression of the decay amplitude in terms of a Euclidean correlation\nfunction starting from the theory defined on the torus. The derivation shows\nthat for timelike photons the approach to the infinite-volume decay amplitude\nis exponential in the periodic box size.",
        "positive": "Lattice Hamiltonian approach to the Schwinger model: further results\n  from the strong coupling expansion: We employ exact diagonalization with strong coupling expansion to the\nmassless and massive Schwinger model. New results are presented for the ground\nstate energy and scalar mass gap in the massless model, which improve the\nprecision to nearly $10^{-9} %$. We also investigate the chiral condensate and\ncompare our calculations to previous results available in the literature.\nOscillations of the chiral condensate which are present while increasing the\nexpansion order are also studied and are shown to be directly linked to the\npresence of flux loops in the system."
    },
    {
        "anchor": "Complex Langevin: Boundary terms at poles: We discuss the problem of possible boundary terms at poles of the drift in\nthe complex Langevin method, which spoil correctness of the method. For the\nsimplest, however paradigmatic cases we can find complete answers. Lessons for\nmore generic cases as well as open mathematical problems are discussed.",
        "positive": "Toward Exploring Phase Diagrams of Gauge Theories on Quantum Computers\n  with Thermal Pure Quantum States: Aiming at evading the notorious sign problem in classical Monte-Carlo\napproaches to lattice quantum chromodynamics, we present an approach for\nquantum computing finite-temperature lattice gauge theories at non-zero\ndensity. Based on the thermal pure-quantum-state formalism of statistical\nmechanics when extended to gauge-theory systems, our approach allows for\nsign-problem-free quantum computations of thermal expectation values and\nnon-equal time correlation functions. By taking a simple lattice gauge theory\nfor which classical benchmarks are possible, namely $\\mathbb{Z}_2$ lattice\ngauge theory in 1+1 dimensions at finite chemical potential, we discuss\nresource requirements and robustness to algorithmic and hardware imperfections\nfor near-term quantum-hardware realizations."
    },
    {
        "anchor": "Nonperturbative QCD corrections to electroweak observables: Nonperturbative QCD corrections are important to many low-energy electroweak\nobservables, for example the muon magnetic moment. However, hadronic\ncorrections also play a significant role at much higher energies due to their\nimpact on the running of standard model parameters, such as the electromagnetic\ncoupling. Currently, these hadronic contributions are accounted for by a\ncombination of experimental measurements, effective field theory techniques and\nphenomenological modeling but ideally should be calculated from first\nprinciples. Recent developments indicate that many of the most important\nhadronic corrections may be feasibly calculated using lattice QCD methods. To\nillustrate this, we will examine the lattice computation of the leading-order\nQCD corrections to the muon magnetic moment, paying particular attention to a\nrecently developed method but also reviewing the results from other\ncalculations. We will then continue with several examples that demonstrate the\npotential impact of the new approach: the leading-order corrections to the\nelectron and tau magnetic moments, the running of the electromagnetic coupling,\nand a class of the next-to-leading-order corrections for the muon magnetic\nmoment. Along the way, we will mention applications to the Adler function,\nwhich can be used to determine the strong coupling constant, and QCD\ncorrections to muonic-hydrogen.",
        "positive": "The finite temperature transition for 2-flavour lattice QCD at finite\n  isospin density: We simulate 2-flavour lattice QCD at finite isospin chemical potential mu_I,\nfor temperatures close to the finite temperature transition from hadronic\nmatter to a quark-gluon plasma. The mu_I dependence of the transition coupling\nis observed and used to estimate the decrease in the transition temperature\nwith increasing mu_I. These simulations are performed on an 8^3 times 4 lattice\nat 3 different quark masses. Our estimate of the magnitude of the fluctuations\nof the phase of the fermion determinant at small quark-number chemical\npotential mu, suggest that the position of the small mu and small mu_I\ntransitions should be the same for mu_I=2mu, and we argue that the nature of\nthese transitions should be the same. For all mu_I < m_pi the smoothness of\nthese transitions and the values of the Binder cumulant B_4, indicate that\nthese transitions are mere crossovers, and show no sign of the expected\ncritical endpoint. For mu_I > m_pi and a small isospin (I_3) breaking term\nlambda, we do find evidence of a critical endpoint which would indicate that,\nfor lambda=0, there is a tricritical point on the phase boundary where the pion\ncondensate evaporates, where this phase transition changes from second to first\norder."
    },
    {
        "anchor": "Quantum simulation of scattering in the quantum Ising model: We discuss real time evolution for the quantum Ising model in one spatial\ndimension with $N_s$ sites. In the limit where the nearest neighbor\ninteractions $J$ in the spatial directions are small, there is a simple\nphysical picture where qubit states can be interpreted as approximate particle\noccupations. Using exact diagonalization, for initial states with one or two\nparticles, we show that for small $J$, discrete Bessel functions provide very\naccurate expressions for the evolution of the occupancies corresponding to\ninitial states with one and two particles. Boundary conditions play an\nimportant role when the evolution time is long enough. We discuss a Trotter\nprocedure to implement the evolution on existing quantum computers and discuss\nthe error associated with the Trotter step size. We discuss the effects of gate\nand measurement errors on the evolution of one and two particle states using 4\nand 8 qubits circuits approximately corresponding to existing or near term\nquantum computers.",
        "positive": "Fluctuations and reweighting of the quark determinant on large lattices: We propose to stabilise HMC simulations of lattice QCD with very light Wilson\nquarks by splitting the quark determinant into two factors and by treating the\nfactor that includes the contribution of the low modes of the Dirac operator as\na reweighting factor. In general, determinant reweighting becomes inefficient\non large lattices, because the statistical fluctuations of quark determinants\nincrease exponentially with the lattice volume. Random matrix theory and some\nnumerical studies now suggest that the low-mode contribution to the determinant\nbehaves differently, which allows factorisations to be devised that preserve\nthe efficiency of the simulation on large lattices."
    },
    {
        "anchor": "Phase Diagram of a Lattice $SU(2) \\times SU(2)$ Scalar-Fermion Model\n  Using the Zaragoza Fermions: We present a calculation of the phase diagram of a $SU(2) \\times SU(2)$\nchiral Yukawa model with massless decoupled doublers, using a saddle point\napproach, both for small and large Yukawa coupling. Some preliminary MonteCarlo\nresults are also shown.",
        "positive": "Heavy quarks on the lattice: status and perspectives: The lattice method for the calculation of weak decay amplitudes of heavy\nquark systems is introduced. Results for leptonic and semi-leptonic decays of\nheavy mesons and $B-\\bar{B}$ mixing are reviewed."
    },
    {
        "anchor": "Exact Simulation of Loops in Lattice Gauge Theory: We exploit the local loop dynamics calculated in prepotential formulation to\ncompute the pertrubation expansion in the strong coupling limit of lattice\ngauge theory. A new exact simulation technique is developed to simulate all\npossible loop states on an infinite lattice using exact BFACF algorithm. This\nloop perturbation numerical calculations are free from any limitation on\nlattice size. Using this, we calculate the correction of string tension for\nSU(2) theory in 2+1 dimension upto order $g^{64}$.",
        "positive": "The phase structure of a chirally invariant lattice Higgs-Yukawa model: We consider a chirally invariant lattice Higgs-Yukawa model based on the\nNeuberger overlap operator. As a first step towards the eventual determination\nof Higgs mass bounds we present the phase structure of the model analytically\nin the large Nf-limit in the physically interesting region of the Yukawa\ncoupling constant. We confront the analytically obtained phase diagram with\ncorresponding HMC-simulations and find an excellent agreement at large values\nof Nf. In the opposite case the large Nf computation still gives a good\nqualitative description of the phase diagram. We also present first and very\npreliminary results on the Higgs upper bound at one selected cut-off of the\ntheory."
    },
    {
        "anchor": "Fast vectorized algorithm for the Monte Carlo Simulation of the Random\n  Field Ising Model: An algoritm for the simulation of the 3--dimensional random field Ising model\nwith a binary distribution of the random fields is presented. It uses\nmulti-spin coding and simulates 64 physically different systems simultaneously.\nOn one processor of a Cray YMP it reaches a speed of 184 Million spin updates\nper second. For smaller field strength we present a version of the algorithm\nthat can perform 242 Million spin updates per second on the same machine.",
        "positive": "Nucleon, Delta and Omega excited state spectra at three pion mass values: The energies of the excited states of the Nucleon, Delta and Omega are\ncomputed in lattice QCD, using two light quarks and one strange quark on\nanisotropic lattices. The calculations are performed at three values of the\npion mass: 392(4), 438(3) and 521(3) MeV. We employ the variational method with\na basis of about ten interpolating operators enabling six energies to be\ndistinguished clearly in each irreducible representation of the octahedral\ngroup. We compare our calculations of nucleon excited states with the low-lying\nexperimental spectrum. There is reasonable agreement for the pattern of states."
    },
    {
        "anchor": "Domain Wall Fermion QCD with the Exact One Flavor Algorithm: Lattice QCD calculations including the effects of one or more non-degenerate\nsea quark flavors are conventionally performed using the Rational Hybrid Monte\nCarlo (RHMC) algorithm, which computes the square root of the determinant of\n$\\mathscr{D}^{\\dagger} \\mathscr{D}$, where $\\mathscr{D}$ is the Dirac operator.\nThe special case of two degenerate quark flavors with the same mass is\ndescribed directly by the determinant of $\\mathscr{D}^{\\dagger} \\mathscr{D}$\n--- in particular, no square root is necessary --- enabling a variety of\nalgorithmic developments, which have driven down the cost of simulating the\nlight (up and down) quarks in the isospin-symmetric limit of equal masses. As a\nresult, the relative cost of single quark flavors --- such as the strange or\ncharm --- computed with RHMC has become more expensive. This problem is even\nmore severe in the context of our measurements of the $\\Delta I = 1/2$ $K\n\\rightarrow \\pi \\pi$ matrix elements on lattice ensembles with $G$-parity\nboundary conditions, since $G$-parity is associated with a doubling of the\nnumber of quark flavors described by $\\mathscr{D}$, and thus RHMC is needed for\nthe isospin-symmetric light quarks as well. In this paper we report on our\nimplementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD\ncollaboration for simulations including single flavors of domain wall quarks.\nWe have developed a new preconditioner for the EOFA Dirac equation, which both\nreduces the cost of solving the Dirac equation and allows us to re-use the bulk\nof our existing high-performance code. Coupling these improvements with careful\ntuning of our integrator, the time per accepted trajectory in the production of\nour 2+1 flavor $G$-parity ensembles with physical pion and kaon masses has been\ndecreased by a factor of 4.2.",
        "positive": "Improved chiral properties of FLIC fermions: The chiral properties of the fat-link irrelevant clover (FLIC) fermion action\nare examined. The improved chiral properties of fermion actions incorporating\nsmoothed links are realized in the FLIC action where only the irrelevant\noperators of the fermion action are constructed with smoothed links. In\nparticular, the histogram of the additive mass renormalization encountered in\nchiral-symmetry breaking Wilson-type fermion actions is seen to narrow upon\nintroducing fat-links in the irrelevant operators. The exceptional\nconfiguration problem of quenched QCD is reduced, enabling access to the light\nquark mass regime of $m_{\\pi} / m_{\\rho} \\sim 0.35$. In particular, quenched\nchiral non-analytic behavior is revealed in the light quark mass dependence of\nthe $\\Delta$-baryon mass. FLIC fermions offer a promising approach to revealing\nthe properties of full QCD at light quark masses."
    },
    {
        "anchor": "Updates on the Columbia plot and its extended/alternative versions: We report on the status of ongoing investigations aiming at locating the\ndeconfinement critical point with standard Wilson fermions and $N_f=2$ flavors\ntowards the continuum limit (standard Columbia plot); locating the tricritical\nmasses at imaginary chemical potential with unimproved staggered fermions at\n$N_f=2$ (extended Columbia plot); identifying the order of the chiral phase\ntransition at $\\mu=0$ for $N_f=2$ via extrapolation from non integer $N_f$\n(alternative Columbia plot).",
        "positive": "Meson-Meson and Meson-Baryon Interactions in Lattice QCD: We study the meson-meson and meson-baryon interactions in lattice QCD. The\nsimulation is performed on 20^3 * 24 lattice at \\beta=5.7 using Wilson gauge\naction and Wilson fermion at the quenched level. By adopting one static quark\nfor each hadron as \"heavy-light meson\" and \"heavy-light-light baryon\", we\ndefine the distance $r$ of two hadrons and extract the inter-hadron potential\nfrom the energy difference of the two-particle state and its asymptotic state.\nWe find that both of the meson-meson and meson-baryon potentials are\nnontrivially weak for the whole range of 0.2 fm <= r <= 0.8 fm. The effect of\nincluding/excluding the quark-exchange diagrams is found to be marginal."
    },
    {
        "anchor": "Comment on \"Fractional topological charges and the lowest Dirac modes\": We comment on a recent article published in Phys. Rev. D98 (2018) no.9,\n094513, arXiv:1811.09029, pointing out severe problems in the numerical\ninvestigation leading to questionable results and misleading conclusions during\ntheir interpretation.",
        "positive": "Gradient flow step-scaling function for SU(3) with $N_f$ = 6 or 4\n  fundamental flavors: Nonperturbative determinations of the renormalization group (RG) $\\beta$\nfunction are crucial to understand properties of gauge-fermion systems at\nstrong coupling and connect lattice simulations and the perturbative\nultraviolet regime. Choosing well-understood, QCD-like systems with SU(3) gauge\ngroup and either six or four fundamental flavors, we investigate their\nstep-scaling $\\beta$ function. In both cases we push the simulations to the\nboundary of chiral symmetry breaking and study the regime $g^2_{GF} \\lesssim\n8.2$ with six, and $g^2_{GF} \\lesssim 6.6$ with four flavors. We carefully\nconsider the lattice discretization errors by comparing three different\ngradient flows (GF), and for each flow three operators to estimate the\nrenormalized finite volume coupling. We also consider the tree level\nimprovement of the coupling. Noteworthy outcome is that nonperturbatively\ndetermined $\\beta$ functions run much slower than perturbatively predicted."
    },
    {
        "anchor": "Hyper-Systolic Processing on APE100/Quadrics: N^2-Loop Computations: We investigate the performance gains from hyper-systolic implementations of\nn^2-loop problems on the massively parallel computer Quadrics, exploiting its\n3-dimensional interprocessor connectivity. For illustration we study the\ncommunication aspects of an exact molecular dynamics simulation of n particles\nwith Coulomb (or gravitational) interactions. We compare the interprocessor\ncommunication costs of the standard-systolic and the hyper-systolic approaches\nfor various granularities. We predict gain factors as large as 3 on the Q4 and\n8 on the QH4 and measure actual performances on these machine configurations.\nWe conclude that it appears feasable to investigate the thermodynamics of a\nfull gravitating n-body problem with O(10000) particles using the new method on\na QH4 system.",
        "positive": "Better Actions: We explain why compact U(1) confines and how to fix it. We show that\nplaquettes of negative trace carry most of the confinement signal in compact\nSU(2). We show how to perform noncompact gauge-invariant simulations without\nauxiliary fields. We suggest a way to simulate fermions without doublers."
    },
    {
        "anchor": "How to extract information from Green's functions in Landau gauge: The infrared behavior of gluon and ghost propagators offers a crucial test of\nconfinement scenarios in Yang-Mills theories. A nonperturbative study of these\npropagators from first principles is possible in lattice simulations, but one\nmust consider significantly large lattice sizes in order to approach the\ninfrared limit. We propose constraints based on general properties of the\npropagators to gain control over the extrapolation of data to the\ninfinite-volume limit. These bounds also provide a way to relate the\npropagators to simpler, more intuitive quantities. We apply our analysis to the\ncase of pure SU(2) gauge theory in Landau gauge, using the largest lattice\nsizes to date. Our results seem to contradict commonly accepted confinement\nscenarios. We argue that it is not so.",
        "positive": "Two-loop computation of a finite volume running coupling on the lattice: In pure SU(2) gauge theory we compute the two-loop coefficient in the\nrelation between the lattice bare coupling and the running coupling defined\nthrough the Schroedinger functional. This result is required to relate the\nlatter to the MSbar-coupling in our programme to compute alpha_s. In addition\nit allows us to implement O(a) improvement of the Schroedinger functional to\ntwo-loop order. The two-loop beta-function is verified in a perturbative\ncomputation on the lattice, and the behavior of expansions in the standard and\nin the Parisi-improved bare couplings are investigated beyond one loop."
    },
    {
        "anchor": "On the Interplay of Monopoles and Chiral Symmetry Breaking in\n  Non-Compact Lattice QED: Non-compact lattice QED is simulated for various numbers of fermion species\n$N_f$ ranging from 8 through 40 by the exact Hybrid Monte Carlo algorithm. Over\nthis range of $N_f$, chiral symmetry breaking is found to be strongly\ncorrelated with the effective monopoles in the theory. For $N_f$ between 8 and\n16 the chiral symmetry breaking and monopole percolation transitions are second\norder and coincident. Assuming powerlaw critical behavior, the correlation\nlength exponent for the chiral transition is identical to that of monopole\npercolation. This result supports the conjecture that monopole percolation\n``drives\" the nontrivial chiral transition. For $N_f$ between 20 and 32, the\nmonopoles experience a first order condensation transition coincident with a\nfirst order chiral transition. For $N_f$ as large as 40 both transitions are\nstrongly suppressed. The data at large $N_f (N_f \\mathrel {\\mathpalette \\vereq\n>} 20)$ is interpreted in terms of a strongly interacting monopole gas-liquid\ntransition.",
        "positive": "The Low-Lying Dirac Spectrum of Staggered Quarks: We investigate and clarify the role of topology and the issues surrounding\nthe epsilon regime for staggered quarks. We study unimproved and improved\nstaggered quark Dirac operators on quenched lattice QCD gluon backgrounds\ngenerated using a Symanzik-improved gluon action. For the improved Dirac\noperators we find a clear separation of the spectrum into would-be zero modes\nand others. The number of would-be zero modes depends on the topological charge\nas predicted by the continuum Index Theorem, and the expectation values of\ntheir chirality are large for the most improved actions (approx 0.7). The\nremaining modes have low chirality and show clear signs of clustering into\nquartets that become degenerate in the continuum limit. We demonstrate that the\nlattice spacing and volume dependence of the eigenvalues follow expectations.\nFurthermore, the non-zero modes follow the random matrix theory predictions for\nall topological charge sectors. The values of the chiral condensate extracted\nfrom fits to the theoretical distributions are consistent with each other, and\nwith the results obtained from the total density of eigenvalues using the\nBanks-Casher relation. We conclude that staggered quarks respond correctly to\nQCD topology when both fermion and gauge actions are improved."
    },
    {
        "anchor": "Scaling behaviour at the $N_t=6$ chiral phase transition for 2-flavour\n  lattice QCD with massless staggered quarks, and an irrelevant 4-fermion\n  interaction: We have simulated lattice QCD with 2 flavours of massless staggered quarks.\nAn irrelevant chiral 4-fermion interaction was added to the standard quark\naction to allow us to simulate at zero quark mass. Thermodynamics was studied\non lattices of temporal extent 6. Clear evidence for a second order chiral\ntransition was observed and the critical exponents $\\beta_{mag}$, $\\delta$,\n$\\nu$ and $\\gamma_{mag}$ were measured. These exponents did not agree with\nthose expected by standard universality arguments. They were, however,\nconsistent with tricritical behaviour. The $\\pi$ and $\\sigma$ screening masses\nwere measured and showed clear evidence for chiral symmetry restoration at this\ntransition.",
        "positive": "Chiral limit of light hadron mass in quenched staggered QCD: We discuss chiral limit of light hadron mass from our quenched staggered\ncalculations with a high lattice cutoff of (a^{-1})(\\sim)3.7 GeV at (\\beta)=6.5\nand a large lattice volume of (48^3\\times 64). We added six heavier quark mass\nvalues of (m_qa)=0.0075, 0.015, 0.02, 0.03, 0.04 and 0.05 to the previously\nexisting 0.01, 0.005, 0.0025, and 0.00125. An interesting curvature is observed\nin the (m_\\pi^2/m_q) to (m_q) plot near (m_qa)=0.01."
    },
    {
        "anchor": "The neutral kaon mixing parameter B_K from unquenched mixed-action\n  lattice QCD: We calculate the neutral kaon mixing parameter B_K in unquenched lattice QCD\nusing asqtad-improved staggered sea quarks and domain-wall valence quarks. We\nuse the \"2+1\" flavor gauge configurations generated by the MILC Collaboration,\nand simulate with multiple valence and sea quark masses at two lattice spacings\nof a ~ 0.12 fm and a ~ 0.09 fm. We match the lattice determination of B_K to\nthe continuum value using the nonperturbative method of Rome-Southampton, and\nextrapolate B_K to the continuum and physical quark masses using mixed action\nchiral perturbation theory. The \"mixed-action\" method enables us to control all\nsources of systematic uncertainty and therefore to precisely determine B_K; we\nfind a value of B_K^{MSbar, NDR}(2 GeV) = 0.527(6)(20), where the first error\nis statistical and the second is systematic.",
        "positive": "Dirac operator normality and chiral fermions: Normality of the Dirac operator is shown to be necessary for chiral\nproperties.\n  From the global chiral Ward identity, which in the continuum limit gives the\nindex theorem, a sum rule results which constrains the spectrum. The\nGinsparg-Wilson relation is to be restricted to its simple form and is a member\nof a set of spectral constraints. A family of alternative chiral\ntransformations is introduced. The one of L\\\"uscher is a special case which\ntransports only the anomaly term to the measure. An alternative transformation\nwould also be needed to correct Fujikawa's path-integral approach. From a\ngeneral function of the hermitean Wilson-Dirac operator the one of Neuberger\nfollows."
    },
    {
        "anchor": "What's new with the electroweak phase transition?: We review the status of non-perturbative lattice studies of the electroweak\nphase transition. In the Standard Model, the complete phase diagram has been\nreliably determined, and the conclusion is that there is no phase transition at\nall for the experimentally allowed Higgs masses. In the Minimal Supersymmetric\nStandard Model (MSSM), in contrast, there can be a strong first order\ntransition allowing for baryogenesis. Finally, we point out possibilities for\nfuture simulations, such as the problem of CP-violation at the MSSM electroweak\nphase boundary.",
        "positive": "On the fourth root prescription for dynamical staggered fermions: With the aim of resolving theoretical issues associated with the fourth root\nprescription for dynamical staggered fermions in Lattice QCD simulations, we\nconsider the problem of finding a viable lattice Dirac operator D such that\n(det D_{staggered})^{1/4} = det D. Working in the flavour field representation\nwe show that in the free field case there is a simple and natural candidate D\nsatisfying this relation, and we show that it has acceptable locality behavior:\nexponentially local with localisation range vanishing ~ (a/m)^{1/2} for lattice\nspacing a -> 0. Prospects for the interacting case are also discussed, although\nwe do not solve this case here."
    },
    {
        "anchor": "Spectrum of the Dirac Operator and Multigrid Algorithm with Dynamical\n  Staggered Fermions: Complete spectra of the staggered Dirac operator $\\Dirac$ are determined in\nquenched four-dimensional $SU(2)$ gauge fields, and also in the presence of\ndynamical fermions.\n  Periodic as well as antiperiodic boundary conditions are used.\n  An attempt is made to relate the performance of multigrid (MG) and conjugate\ngradient (CG) algorithms for propagators with the distribution of the\neigenvalues of~$\\Dirac$.\n  The convergence of the CG algorithm is determined only by the condition\nnumber~$\\kappa$ and by the lattice size.\n  Since~$\\kappa$'s do not vary significantly when quarks become dynamic,\n  CG convergence in unquenched fields can be predicted from quenched\nsimulations.\n  On the other hand, MG convergence is not affected by~$\\kappa$ but depends on\nthe spectrum in a more subtle way.",
        "positive": "QCD equation of state at finite chemical potential from unbiased\n  exponential resummation of the lattice QCD Taylor series: Exponential resummation of the QCD finite-density Taylor series has been\nrecently introduced as an alternative way of resumming the finite-density\nlattice QCD Taylor series. Unfortunately the usual exponential resummation\nformula suffers from stochastic bias which must be subtracted before\nidentifying genuine higher-order contributions. In this paper, we present a new\nway of subtracting the stochastic bias at the level of each individual gauge\nconfiguration, up to a certain order of either the Taylor series or the\ncumulant expansion, by modifying the argument of the exponential. Retaining the\nexponential form of the resummation allows us to also calculate the phase\nfactor of the fermion determinant on each gauge configuration. We present our\nresults for the excess pressure, number density, and the average phase factor\nand show that the new results contain less stochastic bias and are in better\nagreement with the QCD Taylor series compared to the previous exponential\nresummation."
    },
    {
        "anchor": "Systematic study of autocorrelation time in pure SU(3) lattice gauge\n  theory: Results of our autocorrelation measurement performed on Fujitsu AP1000 are\nreported. We analyze (i) typical autocorrelation time, (ii) optimal mixing\nratio between overrelaxation and pseudo-heatbath and (iii) critical behavior of\nautocorrelation time around cross-over region with high statistic in wide range\nof $\\beta$ for pure SU(3) lattice gauge theory on $8^4$, $16^4$ and $32^4$\nlattices. For the mixing ratio K, small value (3-7) looks optimal in the\nconfined region, and reduces the integrated autocorrelation time by a factor\n2-4 compared to the pseudo-heatbath. On the other hand in the deconfined phase,\ncorrelation times are short, and overrelaxation does not seem to matter For a\nfixed value of K(=9 in this paper), the dynamical exponent of overrelaxation is\nconsistent with 2 Autocorrelation measurement of the topological charge on\n$32^3 \\times 64$ lattice at $\\beta$ = 6.0 is also briefly mentioned.",
        "positive": "Improved Landau gauge fixing and the suppression of finite-volume\n  effects of the lattice gluon propagator: For the gluon propagator of pure SU(2) lattice gauge theory in the Landau\ngauge we investigate the effect of Gribov copies and finite-volume effects.\nConcerning gauge fixing, we enlarge the accessible gauge orbits by adding\nnon-periodic Z(2) gauge transformations and systematically employ the simulated\nannealing algorithm. Strategies to keep all Z(2) sectors under control within\nreasonable CPU time are discussed. We demonstrate that the finite-volume\neffects in the infrared regime become ameliorated. Reaching a physical volume\nof about (6.5 fm)^4, we find that the propagator, calculated with the indicated\nimprovements, becomes flat in the region of smallest momenta. First signs in 4d\nof a final decrease towards vanishing momentum are discussed."
    },
    {
        "anchor": "General Methods for Digital Quantum Simulation of Gauge Theories: A general scheme is presented for simulating gauge theories, with matter\nfields, on a digital quantum computer. A Trotterized time-evolution operator\nthat respects gauge symmetry is constructed, and a procedure for obtaining\ntime-separated, gauge-invariant operators is detailed. We demonstrate the\nprocedure on small lattices, including the simulation of a 2+1D non-Abelian\ngauge theory.",
        "positive": "The chiral critical point of Nf=3 QCD at finite density to the order\n  (mu/T)^4: QCD with three degenerate quark flavours at zero baryon density exhibits a\nfirst order thermal phase transition for small quark masses, which changes to a\nsmooth crossover for some critical quark mass m^c_0, i.e. the chiral critical\npoint. It is generally believed that as an (even) function of quark chemical\npotential, m_c(mu), the critical point moves to larger quark masses,\nconstituting the critical endpoint of a first order phase transition in\ntheories with m\\geq m^c_0. To test this, we consider a Taylor expansion of\nm_c(mu) around mu=0 and determine the first two coefficients from lattice\nsimulations with staggered fermions on N_t=4 lattices. We employ two different\ntechniques: a) calculating the coefficients directly from a mu=0 ensemble using\na novel finite difference method, and b) fitting them to simulation data\nobtained for imaginary chemical potentials. The mu^2 and mu^4 coefficients are\nfound to be negative by both methods, with consistent absolute values.\nCombining both methods gives evidence that also the mu^6 coefficient is\nnegative. Hence, on coarse N_t=4 lattices a three-flavour theory with m > m^c_0\ndoes not possess a chiral critical endpoint for quark chemical potentials\nmu\\lsim T. Simulations on finer lattices are required for reliable continuum\nphysics. Possible implications for the QCD phase diagram are discussed."
    },
    {
        "anchor": "$\u03b7$-glueball mixing from $N_f=2$ lattice QCD: We perform the first lattice study on the mixing of the isoscalar\npseudoscalar meson $\\eta$ and the pseudoscalar glueball $G$ in the $N_f=2$ QCD\nat the pion mass $m_\\pi\\approx 350$ MeV. The $\\eta$ mass is determined to be\n$m_\\eta=714(6)(16)$ MeV. Through the Witten-Veneziano relation, this value can\nbe matched to a mass value of $\\sim 981$ MeV for the $\\mathrm{SU(3)}$\ncounterpart of $\\eta$. Based on a large gauge ensemble, the $\\eta-G$ mixing\nenergy and the mixing angle are determined to be $|x|=107(15)(2)$ MeV and\n$|\\theta|=3.46(46)^\\circ$ from the $\\eta-G$ correlators that are calculated\nusing the distillation method. We conclude that the $\\eta-G$ mixing is tiny and\nthe topology induced interaction contributes most of $\\eta$ mass owing to the\nQCD $\\mathrm{U_A(1)}$ anomaly.",
        "positive": "Exploring the transition into the Chiral Regime of QCD using the\n  Interacting Instanton Liquid Model: The non-perturbative quark-gluon interaction depends significantly on the\nvalue of the quark mass. In particular, in the light quark mass regime,\ncorrelations are strongly influenced by dynamics associated to chiral symmetry\nbreaking. We use the Interacting Instanton Liquid Model (IILM) as a tool to\ninvestigate the microscopic dynamical mechanisms which underly the dependence\non the quark mass and drive the transition into the chiral regime of QCD. To\nensure the validity of the model, we first verify that the dependence on the\nquark mass for several observables calculated in the IILM agrees well with the\npredictions of chiral perturbation theory and with lattice simulations. We then\nshow that a quark mass m*~80 MeV emerging naturally from the model specifies\nthe mass scale above which the dynamics associated with low-lying eigenmodes of\nthe Direac operator becomes sub-leading and the contribution of the fermion\ndeterminant is suppressed."
    },
    {
        "anchor": "Twisted reduction in large N QCD with two adjoint Wilson fermions: The twisted reduced model of large $N$ QCD with two adjoint Wilson fermions\nis studied numerically using the Hybrid Monte Carlo method. This is the\none-site model, whose large $N$ limit (large volume limit) is expected to be\nconformal or nearly conformal. The symmetric twist boundary condition with flux\n$k$ is used. $k$=0 corresponds to periodic boundary conditions. It is shown\nthat the quark mass and $N$ dependencies of the model with non-vanishing $k$\ndiffer significantly from those of the $k$=0 model. A preliminary result for\nthe string tension calculated at $N$=289 is presented. The string tension seems\nto vanish as the physical quark mass decreases to zero in a way consistent with\nthe theory being governed by an infrared fixed point with $\\gamma_* = 0.8 \\sim\n1.2$.",
        "positive": "Exploring the 3D Ising gauge-Higgs model in exact Coulomb gauge and with\n  a gauge-invariant substitute for Landau gauge: The Z2 gauge-Higgs model in three dimensions has two different types of phase\ntransition, confinement-deconfinement and Higgs magnetization. Here they are\nexplored through two order parameters, the Coulomb magnetization which is a\nlocal order parameter for confinement, and a replica-based gauge-invariant\norder parameter which tracks the Higgs transition in a way similar to\nLandau-gauge magnetization. Minimal Coulomb gauge is set exactly, using the\npolynomial-time minimum-weight matching algorithm of Edmonds. This is a\ntremendous speed improvement over relaxation/annealing methods and completely\neliminates the systematic error. The replica-overlap is also an improvement\nover relaxation methods for setting Landau gauge, in that it has an easily\ncontrollable and measurable systematic error. These simulations show the phase\ntransitions not ending at the first-order endpoint but bifurcating near there\nand continuing even through the expected analyticity region. The specific heat\ncritical exponents, $\\alpha$, are highly negative, explaining the lack of\nstrong signals in the energy. Nevertheless, energy moments are seen to follow\ncurves consistent with the predictions from the order parameters, showing these\nto be true thermal transitions, albeit weak ones. These results cast further\ndoubt on Fradkin-Shenker analyticity. They also suggest one or more new yet to\nbe explored phases in gauge-Higgs models in the bifurcated region."
    },
    {
        "anchor": "The standard model and parity conservation: On the basis of previous work on chiral gauged fermions on a lattice, we\ndiscuss the lattice-regularization of the standard model by introducing two\nWeyl fields interacting with quarks and leptons. These interactions form\nmassive bound states to gauge-invariantly decouple doublers at high energies\nand these bound states dissolve into their constituents at low energies. No any\nhard spontaneous symmetry breakings occur at the lattice scale \\pi/a. As a\nconsequence, the gauge symmetries of the standard model are realized by both\nmassive vectorlike spectra at high energies and massless chiral spectra at low\nenergies. Such a scenario is consistent with the gauge-anomaly cancelation,\nflavor-singlet anomaly and Witten's anomaly. These studies predict that the\nparity symmetry must be restored at high energies.",
        "positive": "Quark number fluctuations at high temperatures: We calculate the second, fourth and sixth order quark number fluctuations in\nthe deconfined phase of 2+1 flavor QCD using lattices with temporal extent\nNt=4, 6, 8 and 12. We consider light, strange and charm quarks. We use p4\naction for valence quarks and gauge configurations generated with p4 action\nwith physical value of the strange quark mass and light quark mass mq=0.1ms\ngenerated by the RBC-Bielefeld collaboration. We observe that for all quark\nmasses the quark number fluctuations rapidly get close to the corresponding\nideal gas limits. We compare our results to predictions of a quasi-particle\nmodel and resummed high temperature perturbative calculations. We also\ninvestigate correlations among different flavor channels."
    },
    {
        "anchor": "Finite-volume effects in the hadronic vacuum polarization: We investigate finite-volume effects in the hadronic vacuum polarization,\nwith an eye toward the corresponding systematic error in the muon anomalous\nmagnetic moment. While it is well known that leading-order chiral perturbation\ntheory does not provide a good description of the hadronic vacuum polarization,\nit turns out that it gives a much better representation of finite-volume\neffects. Indications are that finite-volume effects cannot be ignored when the\naim is a few percent level accuracy for the hadronic contribution to the muon\nanomalous magnetic moment, even when $m_\\pi L \\sim 4$ and $m_\\pi \\sim 200$ MeV.",
        "positive": "Topological Charge Fluctuations and Low-Lying Dirac Eigenmodes: We discuss the utility of low-lying Dirac eigenmodes for studying the nature\nof topological charge fluctuations in QCD. The implications of previous results\nusing the local chirality histogram method are discussed, and the new results\nusing the overlap Dirac operator in Wilson gauge backgrounds at lattice\nspacings ranging from a~0.04 fm to a~0.12 fm are reported. While the degree of\nlocal chirality does not change appreciably closer to the continuum limit, we\nfind that the size and density of local structures responsible for chiral\npeaking do change significantly. The resulting values are in disagreement with\nthe assumptions of the Instanton Liquid Model. We conclude that the\nfluctuations of topological charge in the QCD vacuum are not locally quantized."
    },
    {
        "anchor": "Proton decay matrix element on the lattice with physical pion mass: Proton decay is one of possible signatures of baryon number violation, which\nhas to exist to explain the baryon asymmetry and the existence of nuclear\nmatter. Proton decays must be mediated through effective low-energy baryon\nnumber violating operators made of three quarks and a lepton. We calculate\nmatrix elements of these operators between the proton and various meson final\nstates using the direct method. We report on preliminary results of matrix\nelement calculation done with the 2+1 dynamical flavor domain wall fermions at\nthe physical point for the first time.",
        "positive": "Comparison of Domain Wall Fermion Multigrid Methods: We present a detailed comparison of several recent and new approaches to\nmultigrid solver algorithms suitable for the solution of 5d chiral fermion\nactions such as Domain Wall fermions in the Shamir formulation, and also for\nthe Partial Fraction and Continued Fraction overlap. Our focus is on the\nacceleration of gauge configuration sampling, and a compact nearest neighbour\nstencil is required to limit the calculational cost of obtaining a coarse\noperator. This necessitates the coarsening of a nearest neighbour operator to\npreserve sparsity in coarsened grids, unlike HDCG. We compare the approaches of\nHDCR and the Multigrid algorithm and also several new hybrid schemes. In this\nwork we introduce a new recursive Chebyshev polynomial based setup scheme. We\nfind that the HDCR approach, can both setup, and solve standard Shamir Domain\nWall Fermions faster than a single solve with red-black preconditioned\nConjugate Gradients on large volumes and for modern GPU systems such as the\nSummit supercomputer. This is promising for the acceleration of HMC,\nparticularly if setup costs are shared across multiple Hasenbusch determinant\nfactors. The setup scheme is likely generally applicable to other Fermion\nactions."
    },
    {
        "anchor": "Exponential suppression of radiatively induced mass in the truncated\n  overlap: A certain truncation of the overlap (domain wall fermions) contains $k$\nflavors of Wilson-Dirac fermions. We show that for sufficiently weak lattice\ngauge fields the effective mass of the lightest Dirac particle is exponentially\nsuppressed in $k$. This suppression is seen to disappear when lattice topology\nis non-trivial. We check explicitly that the suppression holds to one loop in\nperturbation theory. We also provide a new expression for the free fermion\npropagator with an arbitrary additional mass term.",
        "positive": "A toy model of (grand) unified monopoles: We explore the old idea that, in a theory containing several gauge groups,\nthe topological defects of one gauge group coincide with those of another gauge\ngroup. This simple 'unification' constraint has deep consequences, the best\nknown of which is a natural explanation of the fractional electric charge of\nquarks. Here we explore the consequences of this idea for the phase diagram, in\na toy model U(1)x U(1)."
    },
    {
        "anchor": "Lattice QCD and nuclear physics for searches of physics beyond the\n  Standard Model: Low-energy tests of fundamental symmetries are extremely sensitive probes of\nphysics beyond the Standard Model, reaching scales that are comparable, if not\nhigher, than directly accessible at the energy frontier. The interpretation of\nlow-energy precision experiments and their connection with models of physics\nbeyond the Standard Model relies on controlling the theoretical uncertainties\ninduced by the nonperturbative nature of QCD at low energy and of the nuclear\ninteractions. In these proceedings, I will discuss how the interplay of Lattice\nQCD and nuclear Effective Field Theories can lead to improved predictions for\nlow-energy experiments, with controlled uncertainties. I will describe the\nframework of chiral Effective Field Theory, and then discuss a few examples,\nincluding non-standard $\\beta$ decays, neutrinoless double beta decay and\nsearches for electric dipole moments, to highlight the progress achieved in\nrecent years, and the role that Lattice QCD will play in addressing the\nremaining open problems.",
        "positive": "Monopole condensation in the ground state of gauge theories: a disorder\n  parameter: We construct a disorder parameter for dual superconductivity of the ground\nstate of $U(1)$ gauge theory."
    },
    {
        "anchor": "Status of the QCDOC project: A status report is given of the QCDOC project, a massively parallel computer\noptimized for lattice QCD using system-on-a-chip technology. We describe\nseveral of the hardware and software features unique to the QCDOC architecture\nand present performance figures obtained from simulating the current VHDL\ndesign of the QCDOC chip with single-cycle accuracy.",
        "positive": "UV-filtered fermionic Monte Carlo: The short-range modes of the fermionic determinant can be absorbed in the\ngauge action using the loop expansion. The coefficients of this expansion and\nthe zeroes of the polynomial approximating the remainder can be optimized by a\nsimple, practical method. When the multiboson approach is used, this\noptimization results in a faster simulation with fewer auxiliary fields."
    },
    {
        "anchor": "A Framework for Systematic Study of QCD Vacuum Structure II: Coherent\n  Lattice QCD: We propose the formulation of lattice QCD wherein all elements of the theory\n(gauge action, fermionic action, theta-term, and all operators) are constructed\nfrom a single object, namely the lattice Dirac operator D with exact chiral\nsymmetry. Several regularizations of this type are suggested via constructing\nscalar densities (gauge actions) that are explicit functions of D. The simplest\nof these is based on the proposition that classical limit of density associated\nwith Tr D is (up to an additive constant) proportional to FF, while the\ncorresponding operator is local. The possibilities of explicit interrelations\nbetween gauge and fermionic aspects of the theory are emphasized together with\nthe utility of such formulations for exploring the QCD vacuum structure.",
        "positive": "Extracting Low-Lying Lambda Resonances Using Correlation Matrix\n  Techniques: The lowest-lying negative-parity state of the Lambda is investigated in\n(2+1)-flavour full-QCD on the PACS-CS configurations made available through the\nILDG. We show that a variational analysis using multiple source and sink\nsmearings can extract a state lying lower than that obtained by using a\nstandard fixed smeared source and sink operator alone."
    },
    {
        "anchor": "Rotating lattice: We present the lattice QCD formulation in rotating frames. We start with the\ncontinuum QCD action in rotating frames, and then discretize it on the lattice.\nFor the first test of the formulation, we calculate angular momentum in the\nquenched Monte Carlo simulation, and confirm that the formulation works\nsuccessfully.",
        "positive": "PQChPT with Staggered Sea and Valence Ginsparg-Wilson Quarks: Vector\n  Meson Masses: We consider partially quenched, mixed chiral perturbation theory with\nstaggered sea and Ginsparg-Wilson valence quarks in order to extract a\nchiral-continuum extrapolation expression for the vector meson mass up to order\nO(a^2), at one-loop level. Based on general principles, we accomplish the task\nwithout explicitly constructing a sophisticated, heavy vector meson chiral\nLagrangian."
    },
    {
        "anchor": "Multicanonical Cluster Algorithm and the 2-D 7-State Potts Model: I present a hybrid-like two-step algorithm, which combines a microcanonical\nupdate of a spin system using demons, with a multicanonical demon refresh. The\nalgorithm is free from the supercritical slowing down that burdens the\ncanonical methods: the exponential increase of the tunnelling time between the\nmetastable states in the first-order phase transitions, when the volume of the\nsystem is increased. The demons act as a buffer between the multicanonical heat\nbath and the spin system, allowing the spin system to be updated with any\nmicrocanonical demon procedure, including cluster methods. The cluster\nalgorithm is demonstrated with the 2-dimensional 7-state Potts model, using\nvolumes up to $128^2$. The tunnelling time is found to increase as $L^{1.82}$,\nwhere $L$ is the linear dimension of the system.",
        "positive": "Multicanonical Recursions: The problem of calculating multicanonical parameters recursively is\ndiscussed. I describe in detail a computational implementation which has worked\nreasonably well in practice."
    },
    {
        "anchor": "Kaon semileptonic vector form factor with $N_f=2+1+1$ Twisted Mass\n  fermions: We investigate the vector form factor relevant for the $K_{\\ell 3}$\nsemileptonic decay using maximally twisted-mass fermions with 4 dynamical\nflavours ($N_f=2+1+1$). Our simulations feature pion masses ranging from $210$\nMeV to approximately $450$ MeV and lattice spacing values as small as $0.06$fm.\nOur main result for the vector form factor at zero 4-momentum transfer is\n$f_+(0)=0.9683(65)$ where the uncertainty is both statistical and systematic.\nBy combining our result with the experimental value of $f_+(0)|V_{us}|$ we\nobtain $|V_{us}|=0.2234(16)$, which satisfies the unitarity constraint of the\nStandard Model at the permille level.",
        "positive": "$K\\to \u03c0\u03c0$ Decay Amplitude on the Lattice: Recent theoretical and numerical progresses of the lattice calculations of\n$K\\to\\pi\\pi$ decay amplitude are reviewed."
    },
    {
        "anchor": "A density of states approach to the hexagonal Hubbard model at finite\n  density: We apply the Linear Logarithmic Relaxation (LLR) method, which generalizes\nthe Wang-Landau algorithm to quantum systems with continuous degrees of\nfreedom, to the fermionic Hubbard model with repulsive interactions on the\nhoneycomb lattice. We compute the generalized density of states of the average\nHubbard field and divise two reconstruction schemes to extract physical\nobservables from this result. By computing the particle density as a function\nof chemical potential we assess the utility of LLR in dealing with the sign\nproblem of this model, which arises away from half filling. We show that the\nrelative advantage over brute-force reweighting grows as the interaction\nstrength is increased and discuss possible future improvements.",
        "positive": "Non-perturbative improvement of bilinears in unquenched QCD: We describe how the improvement of quark bilinears generalizes from quenched\nto unquenched QCD, and discuss which of the additional improvement constants\ncan be determined using Ward Identities."
    },
    {
        "anchor": "Simulations with different lattice Dirac operators for valence and sea\n  quarks: We discuss simulations with different lattice Dirac operators for sea and\nvalence quarks. A goal of such a \"mixed\" action approach is to probe deeper the\nchiral regime of QCD by enabling simulations with light valence quarks. This is\nachieved by using chiral fermions as valence quarks while computationally\ninexpensive fermions are used in the sea sector. Specifically, we consider\nWilson sea quarks and Ginsparg-Wilson valence quarks. The local Symanzik action\nfor this mixed theory is derived to O(a), and the appropriate low energy chiral\neffective Lagrangian is constructed, including the leading O(a) contributions.\nUsing this Lagrangian one can calculate expressions for physical observables\nand determine the Gasser-Leutwyler coefficients by fitting them to the lattice\ndata.",
        "positive": "Static quark potential from centre vortices in the presence of dynamical\n  fermions: For the first time, centre vortices are identified on SU(3) lattice ensembles\nthat include dynamical fermions. Using a variational method, the static quark\npotential is calculated on untouched, vortex-removed, and vortex-only fields.\nTwo dynamical ensembles and one pure gauge ensemble are studied, allowing for\nan exploration of the impact of dynamical fermions on the centre-vortex vacuum.\nNovel modifications to the standard Coulomb term are introduced to describe the\nlong range behaviour of the vortex-removed potential. These modifications\nremove a source of systematic error in the fitted string tension on the\noriginal ensembles. Our pure Yang-Mills result is consistent with previous\nstudies, where projected centre-vortex fields only reproduce approximately two\nthirds of the string tension. Remarkably, we find that the vortex-only fields\non both dynamical lattices are able to fully reproduce the respective untouched\nstring tensions."
    },
    {
        "anchor": "Current Physics Results from Staggered Chiral Perturbation Theory: We review several results that have been obtained using lattice QCD with the\nstaggered quark formulation. Our focus is on the quantities that have been\ncalculated numerically with low statistical errors and have been extrapolated\nto the physical quark mass limit and continuum limit using staggered chiral\nperturbation theory. We limit our discussion to a brief introduction to\nstaggered quarks, and applications of staggered chiral perturbation theory to\nthe pion mass, decay constant, and heavy-light meson decay constants.",
        "positive": "Satisfying positivity requirement in the Beyond Complex Langevin\n  approach: The problem of finding a positive distribution, which corresponds to a given\ncomplex density, is studied. By the requirement that the moments of the\npositive distribution and of the complex density are equal, one can reduce the\nproblem to solving the matching conditions. These conditions are a set of\nquadratic equations, thus Groebner basis method was used to find its solutions\nwhen it is restricted to a few lowest-order moments. For a Gaussian complex\ndensity, these approximate solutions are compared with the exact solution, that\nis known in this special case."
    },
    {
        "anchor": "Matching of $N_f=2+1$ CLS ensembles to a tmQCD valence sector: A mixed action composed of valence quark flavours regularized with a\nfully-twisted tmQCD action and of $N_f=2+1$ flavours of non-perturbatively\n${\\rm O}(a)$-improved Wilson sea quarks is described. Two procedures for the\nmatching of sea and valence quark masses are discussed. We report about a\ncomparison of the continuum-limit scaling of pseudoscalar meson observables and\nof quark masses using the sea and valence actions.",
        "positive": "QCD equation of state in the presence of magnetic fields at low density: Peripheral heavy-ion collisions are expected to exhibit magnetic fields with\nmagnitudes comparable to the QCD scale, as well as non-zero baryon densities.\nWhereas QCD at finite magnetic fields can be simulated directly with standard\nlattice algorithms, the implementation of real chemical potentials is hindered\nby the infamous sign problem. Aiming to shed light on the QCD transition and on\nthe equation of state in that regime, we carry out lattice QCD simulations with\n2+1+1 flavors of staggered quarks with physical masses at finite magnetic\nfields and employ a Taylor expansion scheme to circumvent the sign problem. We\npresent the leading-order coefficient of the expansion calculated at non-zero\nmagnetic fields and discuss the impact of the field on the strangeness\nneutrality condition."
    },
    {
        "anchor": "Composite Vector Particles in External Electromagnetic Fields: Lattice quantum chromodynamics (QCD) studies of electromagnetic properties of\nhadrons and light nuclei, such as magnetic moments and polarizabilities, have\nproven successful with the use of background field methods. With an\nimplementation of nonuniform background electromagnetic fields, properties such\nas charge radii and higher electromagnetic multipole moments (for states of\nhigher spin) can be additionally obtained. This can be achieved by matching\nlattice QCD calculations to a corresponding low-energy effective theory that\ndescribes the static and quasi-static response of hadrons and nuclei to weak\nexternal fields. With particular interest in the case of vector mesons and\nspin-1 nuclei such as the deuteron, we present an effective field theory of\nspin-1 particles coupled to external electromagnetic fields. To constrain the\ncharge radius and the electric quadrupole moment of the composite spin-1 field,\nthe single-particle Green's functions in a linearly varying electric field in\nspace are obtained within the effective theory, providing explicit expressions\nthat can be used to match directly onto lattice QCD correlation functions. The\nviability of an extraction of the charge radius and the electric quadrupole\nmoment of the deuteron from the upcoming lattice QCD calculations of this\nnucleus is discussed.",
        "positive": "Improved Smoothing Algorithms for Lattice Gauge Theory: The relative smoothing rates of various gauge field smoothing algorithms are\ninvestigated on ${\\cal O}(a^2)$-improved $\\suthree$ Yang--Mills gauge field\nconfigurations. In particular, an ${\\cal O}(a^2)$-improved version of APE\nsmearing is motivated by considerations of smeared link projection and cooling.\nThe extent to which the established benefits of improved cooling carry over to\nimproved smearing is critically examined. We consider representative gauge\nfield configurations generated with an ${\\cal O}(a^2)$-improved gauge field\naction on $\\1$ lattices at $\\beta=4.38$ and $\\2$ lattices at $\\beta=5.00$\nhaving lattice spacings of 0.165(2) fm and 0.077(1) fm respectively. While the\nmerits of improved algorithms are clearly displayed for the coarse lattice\nspacing, the fine lattice results put the various algorithms on a more equal\nfooting and allow a quantitative calibration of the smoothing rates for the\nvarious algorithms. We find the relative rate of variation in the action may be\nsuccinctly described in terms of simple calibration formulae which accurately\ndescribe the relative smoothness of the gauge field configurations at a\nmicroscopic level."
    },
    {
        "anchor": "Comparison of gluon flux-tube distributions for quark-diquark and\n  quark-antiquark hadrons: The distribution of gluon fields in hadrons is of fundamental interest in\nQCD. Using lattice QCD we have observed the formation of gluon flux tubes\nwithin 3 quark (baryon) and quark plus antiquark (meson) systems for a wide\nvariety of spatial distributions of the color sources. In particular we have\ninvestigated three quark configurations where two of the quarks are close\ntogether and the third quark is some distance away, which approximates a quark\nplus diquark string. We find that the string tension of the quark-diquark\nstring is the same as that of the quark-antiquark string on the same lattice.\nWe also compare the longitudinal and transverse profiles of the gluon flux\ntubes for both sets of strings, and find them to be of similar radii and to\nhave similar vacuum suppression.",
        "positive": "The topological susceptibility in the large-N limit of SU(N) Yang-Mills\n  theory: We compute the topological susceptibility of the SU(N) Yang-Mills theory in\nthe large-N limit with a percent level accuracy. This is achieved by measuring\nthe gradient-flow definition of the susceptibility at three values of the\nlattice spacing for N=3,4,5,6. Thanks to this coverage of parameter space, we\ncan extrapolate the results to the large-N and continuum limits with\nconfidence. Open boundary conditions are instrumental to make simulations\nfeasible on the finer lattices at the larger N."
    },
    {
        "anchor": "Low-energy couplings of QCD from current correlators near the chiral\n  limit: We investigate a new numerical procedure to compute fermionic correlation\nfunctions at very small quark masses. Large statistical fluctuations, due to\nthe presence of local ``bumps'' in the wave functions associated with the\nlow-lying eigenmodes of the Dirac operator, are reduced by an exact low-mode\naveraging. To demonstrate the feasibility of the technique, we compute the\ntwo-point correlator of the left-handed vector current with Neuberger fermions\nin the quenched approximation, for lattices with a linear extent of L~1.5 fm, a\nlattice spacing a~0.09 fm, and quark masses down to the epsilon-regime. By\nmatching the results with the corresponding (quenched) chiral perturbation\ntheory expressions, an estimate of (quenched) low-energy constants can be\nobtained. We find agreement between the quenched values of F extrapolated from\nthe p-regime and extracted in the epsilon-regime.",
        "positive": "The B Meson Decay Constant from Unquenched Lattice QCD: We present determinations of the B meson decay constant f_B and of the ratio\nf_{B_s}/f_B using the MILC collaboration unquenched gauge configurations which\ninclude three flavors of light sea quarks. The mass of one of the sea quarks is\nkept around the strange quark mass, and we explore a range in masses for the\ntwo lighter sea quarks down to m_s/8.\n  The heavy b quark is simulated using Nonrelativistic QCD, and both the\nvalence and sea light quarks are represented by the highly improved (AsqTad)\nstaggered quark action.\n  The good chiral properties of the latter action allow for a much smoother\nchiral extrapolation to physical up and down quarks than has been possible in\nthe past. We find f_B = 216(9)(19)(4) (6) MeV and f_{B_s} /f_B = 1.20(3)(1)."
    },
    {
        "anchor": "Distribution law of the Dirac eigenmodes in QCD: The near-zero modes of the Dirac operator are connected to spontaneous\nbreaking of chiral symmetry in QCD (SBCS) via the Banks-Casher relation. At the\nsame time the distribution of the near-zero modes is well described by the\nRandom Matrix Theory (RMT) with the Gaussian Unitary Ensemble (GUE). Then it\nhas become a standard lore that a randomness, as observed through distributions\nof the near-zero modes of the Dirac operator, is a consequence of SBCS. The\nhigher-lying modes of the Dirac operator are not affected by SBCS and are\nsensitive to confinement physics and related $SU(2)_{CS}$ and $SU(2N_F)$\nsymmetries. We study the distribution of the near-zero and higher-lying\neigenmodes of the overlap Dirac operator within $N_F=2$ dynamical simulations.\nWe find that both the distributions of the near-zero and higher-lying modes are\nperfectly described by GUE of RMT. This means that randomness, while consistent\nwith SBCS, is not a consequence of SBCS and is related to some more general\nproperty of QCD in confinement regime.",
        "positive": "Relative weights approach to dynamical fermions at finite densities: The method of relative weights, coupled with mean field theory, is applied to\nthe problem of simulating gauge theories with dynamical staggered fermions at\nfinite densities. We present initial results and discuss issues so far\nencountered."
    },
    {
        "anchor": "A note on the vacuum structure to lattice Euclidean quantum gravity: It is shown that the ground state or vacuum to the lattice Euclidean quantum\ngravity is significantly different from the ground states to the well-known\nvacua in QED, QCD, et cetera. In the case of the lattice Euclidean quantum\ngravity, the long-wavelength scale vacuum structure is similar to that in QED,\nmoreover the quantum fluctuations to gravity are very reduced in comparison\nwith the situation in QED. But the small scale (of the order of the lattice\nscale) vacuum structure to gravity is significantly different from that to the\nlong-wavelength scales: the fluctuation values of geometrical degrees of\nfreedom (tetrads) are commensurable with theirs most probable values.",
        "positive": "Transport properties of the quark-gluon plasma from lattice QCD: I review the progress made in extracting transport properties of the\nquark-gluon plasma from lattice QCD simulations. The information on shear and\nbulk viscosity, the \"low-energy constants\" of hydrodynamics, is encoded in the\nretarded correlators of Tmunu, the energy-momentum tensor. Euclidean\ncorrelators, computable on the lattice, are related to the retarded correlators\nby an integral transform. The most promising strategy to extract shear and bulk\nviscosity is to study the shear and sound channel correlators where the\nhydrodynamic modes dominate. I present preliminary results from a comprehensive\nstudy of the gluonic plasma between 0.95Tc and 4.0Tc."
    },
    {
        "anchor": "Perturbative running of the twisted Yang-Mills coupling in the gradient\n  flow scheme: We report on our ongoing computation of the perturbative running of the\nYang-Mills coupling using gradient flow techniques. In particular, we use the\ngradient flow method with twisted boundary conditions to perform a perturbative\nexpansion of the expectation value of the Yang-Mills energy density up to\nfourth order in the coupling at finite flow time. We regularise the resulting\nintegrals using dimensional regularisation, and reproduce the universal\ncoefficient of the 1/{\\epsilon} term in the relation between bare and\nrenormalised couplings. The computation of the finite part leading to a\ndetermination of the {\\Lambda} parameter in this scheme is underway.",
        "positive": "Connected Parts of Decuplet Electromagnetic Properties: We determine the electromagnetic properties of decuplet resonances using\nchiral perturbation theory at next-to-leading order. Utilizing a partially\nquenched charge matrix, we isolate and remove the quark disconnected\ncontractions. This allows us to compare the physical meson loop contributions\nto the connected contributions, of which the latter are currently calculated\nusing lattice QCD. Finally we determine linear combinations of decuplet\nresonance and hyperon electromagnetic properties that are exactly independent\nof disconnected contractions in the isospin limit."
    },
    {
        "anchor": "Topology density correlator on dynamical domain-wall ensembles with\n  nearly frozen topological charge: Global topological charge decorrelates very slowly or even freezes in fine\nlattice simulations. On the other hand, its local fluctuations are expected to\nsurvive and lead to the correct physical results as long as the volume is large\nenough. We investigate this issue on recently generated configurations\nincluding dynamical domain-wall fermions at lattice spacings a = 0.08 fm and\nfiner. We utilize the Yang-Mills gradient flow to define the topological charge\ndensity operator and calculate its long-distance correlation, through which we\npropose a new method for extracting the topological susceptibility in a\nsub-volume. This method takes care of the finite volume correction, which\nreduces the bias caused by the global topological charge. Our lattice data\nclearly show a shorter auto-correlation time than that of the naive definition\nusing the whole lattice, and are less sensitive to the global topological\nhistory. Numerical results show a clear sea-quark mass dependence, which agrees\nwell with the prediction of chiral perturbation theory.",
        "positive": "Chiral Perturbation Theory and the Quenched Approximation of QCD: The quenched approximation for QCD is, at present and in the foreseeable\nfuture, unavoidable in lattice calculations with realistic choices of the\nlattice spacing, volume and quark masses. In these lectures, I review the\nanalytic study of the effects of quenching based on chiral perturbation theory.\nQuenched chiral perturbation theory leads to quantitative insight into the\ndifference between quenched and unquenched QCD, and reveals clearly diseases\nwhich plague quenched QCD. A short review of the ideas underlying chiral\nperturbation theory is included."
    },
    {
        "anchor": "Study of $I=0$ bottomonium bound states and resonances based on lattice\n  QCD static potentials: We investigate $I = 0$ bottomonium bound states and resonances in S, P, D and\nF waves using lattice QCD static-static-light-light potentials. We consider\nfive coupled channels, one confined quarkonium and four open\n$B^{(*)}\\bar{B}^{(*)}$ and $B^{(*)}_s\\bar{B}^{(*)}_s$ meson-meson channels and\nuse the Born-Oppenheimer approximation and the emergent wave method to compute\npoles of the T matrix. We discuss results for masses and decay widths and\ncompare them to existing experimental results. Moreover, we determine the\nquarkonium and meson-meson composition of these states to clarify, whether they\nare ordinary quarkonium or should rather be interpreted as tetraquarks.",
        "positive": "Transition of $\u03c1\\rightarrow \u03c0\u03b3$ in Lattice QCD: With the ongoing experimental interest in exploring the excited hadron\nspectrum, evaluations of the matrix elements describing the formation and decay\nof such states via radiative processes provide us with an important connection\nbetween theory and experiment. In particular, determinations obtained via the\nlattice allow for a direct comparison of QCD-expectation with experimental\nobservation. Here we present the first light quark determination of the $\\rho\n\\rightarrow \\pi \\gamma$ transition form factor from lattice QCD using dynamical\nquarks. Using the PACS-CS 2+1 flavour QCD ensembles we are able to obtain\nresults across a range of masses, to the near physical value of $m_\\pi = 157$\nMeV. An important aspect of our approach is the use of variational methods to\nisolate the desired QCD eigenstate. For low-lying states, such techniques\nfacilitate the removal of excited state contributions. In principle the method\nenables one to consider arbitrary eigenstates. We find our results are in\naccord with the non-relativistic quark model for heavy masses. In moving\ntowards the light-quark regime we observe an interesting quark mass dependence,\ncontrary to the quark model expectation. Comparison of our light-quark result\nwith experimental determinations highlights a significant discrepancy\nsuggesting that disconnected sea-quark loop contributions may play a\nsignificant role in fully describing this process."
    },
    {
        "anchor": "Minimal Walking on the Lattice: We provide the first evidence of a walking dynamics for two color lattice\nYang-Mills theory with two Dirac flavors in the symmetric representation of the\ngauge group.",
        "positive": "Extracting hadron masses from fixed topology simulations: Lattice QCD simulations tend to become stuck in a single topological sector\nat fine lattice spacing or when using chirally symmetric overlap quarks. In\nsuch cases physical observables differ from their full QCD counterparts by\nfinite volume corrections. These systematic errors need to be understood on a\nquantitative level and possibly be removed. In this paper we extend an existing\nrelation from the literature between two-point correlation functions at fixed\nand the corresponding hadron masses at unfixed topology by calculating all\nterms proportional to $1/V^2$ and $1/V^3$, where $V$ is the spacetime volume.\nSince parity is not a symmetry at fixed topology, parity mixing is\ncomprehensively discussed. In the second part of this work we apply our\nequations to a simple model, quantum mechanics on a circle both for a free\nparticle and for a square-well potential, where we demonstrate in detail, how\nto extract physically meaningful masses from computations or simulations at\nfixed topology."
    },
    {
        "anchor": "Lattice QCD in rotating frames: We formulate lattice QCD in rotating frames to study the physics of QCD\nmatter under rotation. We construct the lattice QCD action with the rotational\nmetric and apply it to the Monte Carlo simulation. As the first application, we\ncalculate the angular momenta of gluons and quarks in the rotating QCD vacuum.\nThis new framework is useful to analyze various rotation-related phenomena in\nQCD.",
        "positive": "P-wave nucleon-pion scattering amplitude in the $\u0394(1232)$ channel\n  from lattice QCD: We determine the $\\Delta(1232)$ resonance parameters using lattice QCD and\nthe L\\\"uscher method. The resonance occurs in elastic pion-nucleon scattering\nwith $J^P=3/2^+$ in the isospin $I = 3/2$, $P$-wave channel. Our calculation is\nperformed with $N_f=2+1$ flavors of clover fermions on a lattice with $L\\approx\n2.8$ fm. The pion and nucleon masses are $m_\\pi =255.4(1.6)$ MeV and\n$m_N=1073(5)$ MeV, and the strong decay channel $\\Delta \\rightarrow \\pi N$ is\nfound to be above the threshold. To thoroughly map out the energy-dependence of\nthe nucleon-pion scattering amplitude, we compute the spectra in all relevant\nirreducible representations of the lattice symmetry groups for total momenta up\nto $\\vec{P}=\\frac{2\\pi}{L}(1,1,1)$, including irreps that mix $S$ and $P$\nwaves. We perform global fits of the amplitude parameters to up to 21 energy\nlevels, using a Breit-Wigner model for the $P$-wave phase shift and the\neffective-range expansion for the $S$-wave phase shift. From the location of\nthe pole in the $P$-wave scattering amplitude, we obtain the resonance mass\n$m_\\Delta=1378(7)(9)$ MeV and the coupling $g_{\\Delta\\text{-}\\pi\nN}=23.8(2.7)(0.9)$."
    },
    {
        "anchor": "Lattice QCD with Optimal Domain-Wall Fermion: Light Meson Spectroscopy: We perform lattice simulations of two flavors QCD using the optimal\ndomain-wall fermion, in which the chiral symmetry is preserved to a good\nprecision ($ m_{res} \\sim 0.3 $ MeV) on the $ 16^3 \\times 32 $ lattice ($ L\n\\sim 2 $ fm) with inverse lattice spacing $ a^{-1} \\sim 1.8 $ GeV, and $ N_s =\n16 $ in the fifth dimension, for eight sea quark masses corresponding to the\npion masses in the range 210-500 MeV. We present our first results of the mass\nand the decay constant of the pseudoscalar meson, which are in good agreement\nwith the next-to-leading order chiral perturbation theory for $ M_\\pi < 450 $\nMeV, and from which we determine the low-energy constants $ f $, $ \\Sigma $, $\n\\bar{l}_3 $ and $ \\bar{l}_4 $. At the physical pion mass $ M_{\\pi} = 135$ MeV,\nwe obtain the pion decay constant $f_\\pi =133(1)(2)$ MeV, and the average up\nand down quark mass $m_{ud}^{\\bar{\\rm MS}}(\\mathrm{2 GeV})=4.09(7)(11)$ MeV,\nwhere the first error is statistical, and the second error is systematic due to\nthe truncation of the higher order corrections and the uncertainty in the\ndetermination of the lattice spacing. Furthermore, we also obtain the chiral\ncondensate $ \\Sigma^{\\bar{{\\mathrm{MS}}}}(2 GeV) = [250(4)(7) MeV]^3 $.",
        "positive": "Topological Updating Schemes: A Case Study In 3-d U(1): We study a topological updating scheme in three dimensional U(1) gauge\ntheory. Some expectations for four dimensional SU(N) gauge theories are\ndiscussed."
    },
    {
        "anchor": "3-d Lattice QCD Free Energy to Four Loops: We compute the expansion of the 3-d Lattice QCD free energy to four loop\norder by means of Numerical Stochastic Perturbation Theory. The first and\nsecond order are already known and are correctly reproduced. The third and\nfourth order coefficients are new results. The known logarithmic divergence in\nthe fourth order is correctly identified. We comment on the relevance of our\ncomputation in the context of dimensionally reduced finite temperature QCD.",
        "positive": "Non-perturbative renormalization of the energy-momentum tensor in SU(3)\n  Yang-Mills theory: We present a strategy for a non-perturbative determination of the finite\nrenormalization constants of the energy-momentum tensor in the SU(3) Yang-Mills\ntheory. The computation is performed by imposing on the lattice suitable Ward\nIdentites at finite temperature in presence of shifted boundary conditions. We\nshow accurate preliminary numerical data for values of the bare coupling g_0^2\nranging for 0 to 1."
    },
    {
        "anchor": "Gauge Dependence of Effective Quark Mass and Matrix Elements in\n  Gaugefixed Large $N$ Strong Coupling Lattice QCD: In conjunction with recent numerical \\hbox{$\\lambda~\\partial_0 A_0 +\n\\nabla\\cdot\\vec{A} =0$} ``$\\lambda$-gauge'' results reported in a companion\npaper, we construct an $N\\to\\infty$ Wilson loop picture of\n$\\lambda$-gaugefixing in which (I)the $\\lambda$-gauge expectation value of a\nlink chain $C$ is the weighted sum over Wilson loops made by joining to $C$ all\nselfavoiding chains $\\widetilde{C}$ closing $C$. (II)Weights\n$A_{\\widetilde{C}}$, containing all the $\\lambda$-dependence, are given by the\n$\\beta=0$ $\\lambda$-gauge expectation value of $\\widetilde{C}$.\n(III)$A_{\\widetilde{C}}$ equals path-products of coefficients from the trace\nexpansion of the gaugefixing Boltzmann weight. From (II) and (III) we deduce\nformulas for $\\beta =0$ quark matrix elements. We find that $M_q^{(\\lambda)}$\ndecreases with increasing $\\lambda$; the quark propagator dispersion relation\nis not covariant when $\\lambda\\ne 1$; and $\\Delta I=1/2$ matching coefficients\nare $\\lambda$-independent. These strong coupling features are qualitatively\nconsistent with numerical $\\beta=5.7$ and $6.0$ results briefly described here\nfor comparison purposes but mainly presented in a companion paper.",
        "positive": "Chiral phase transition of (2+1)-flavor QCD: We present here results on the determination of the critical temperature in\nthe chiral limit for (2+1)-flavor QCD. We propose two novel estimators of the\nchiral critical temperature where quark mass dependence is strongly suppressed\ncompared to the conventional estimator using pseudo-critical temperatures. We\nhave used the HISQ/tree action for the numerical simulation with lattices with\nthree different temporal extent $N_{\\tau}=$6, 8, 12 and varied the aspect ratio\nover the range $4 \\leq N_{\\sigma}/N_{\\tau} \\leq 8$. To approach the chiral\nlimit, the light quark mass has been decreased keeping the strange quark mass\nfixed at its physical value. Our simulations correspond to the range of pion\nmasses, 55 MeV $\\leq m_{\\pi} \\leq$ 160 MeV."
    },
    {
        "anchor": "Hadron Spectrum and Decay Constant from $N_F=2$ Domain Wall QCD: We report on the first large-scale study of two flavor QCD with domain wall\nfermions (DWF). Simulation has been carried out at three dynamical quark mass\nvalues about 1/2, 3/4, and 1 $m_{strange}$ on $16^3\\times 32$ volume with\n$L_s=12$ and $a^{-1}\\approx 1.7$ GeV. After discussing the details of the\nsimulation, we report on the light hadron spectrum and decay constants.",
        "positive": "Complex Langevin dynamics: criteria for correctness: The complex Langevin method is a leading candidate for solving the sign\nproblem occurring in various physical situations, notably QCD at finite\nchemical potential. Its most vexing problem is `convergence to the wrong\nlimit', where the simulation gives a well defined, but incorrect, result. Here,\nwe first outline a formal justification of the method and identify points at\nwhich it might fail. From these we derive a condition that must be satisfied in\norder for correct results to be obtained. We then apply these ideas to the\nthree-imensional SU(3) spin model at finite chemical potential and show strong\nindications that complex Langevin dynamics yields correct results in this\ntheory."
    },
    {
        "anchor": "The Strong-Coupling Expansion in Simplicial Quantum Gravity: We construct the strong-coupling series in 4d simplicial quantum gravity up\nto volume 38. It is used to calculate estimates for the string susceptibility\nexponent gamma for various modifications of the theory. It provides a very\nefficient way to get a first view of the phase structure of the models.",
        "positive": "A new approach for studying large numbers of fermions in the unitary\n  regime: A novel lattice approach is presented for studying systems comprising a large\nnumber of interacting nonrelativistic fermions. The construction is ideally\nsuited for numerical study of fermions near unitarity--a strongly coupled\nregime corresponding to the two-particle s-wave scattering phase shift delta_0\n= pi/2. Such systems may be achieved experimentally with trapped atoms, and\nprovide a starting point for an effective field theory description of nuclear\nphysics. We discuss the construction of our lattice theory, which allows us to\nstudy systems of up to (but by no means limited to) 38 fermions with high\naccuracy and modest computational resources, and offer an overview of several\napplications of the technique. A more detailed discussion of applications and\nsimulation results will be described in companion proceedings by A. N. N. and\nJ-W. L."
    },
    {
        "anchor": "Pion-pion scattering phase shifts with the stochastic LapH method: Progress in calculating scattering phase shifts on $N_f=2+1$ anisotropic\nclover Wilson lattices is described. The stochastic LapH method facilitates\ncomputations in large volumes and for light pion masses. Results for pion\nmasses down to 240 MeV, keeping $m_\\pi L > 4$, are presented.",
        "positive": "The chiral phase transition at non-zero imaginary baryon chemical\n  potential for different numbers of quark flavours: The so-called Columbia plot summarises the order of the QCD thermal\ntransition as a function of the number of quark flavours and their masses.\nRecently, it was demonstrated that the first-order chiral transition region, as\nseen for $N_f \\in [ 3,6 ]$ on coarse lattices, exhibits tricritical scaling\nwhile extrapolating to zero on sufficiently fine lattices. Here we extend these\nstudies to imaginary baryon chemical potential. A similar shrinking of the\nfirst-order region is observed with decreasing lattice spacing, which again\nappears compatible with a tricritical extrapolation to zero."
    },
    {
        "anchor": "Quenching 2D Quantum Gravity: We simulate the Ising model on a set of fixed random $\\phi^3$ graphs, which\ncorresponds to a {\\it quenched} coupling to 2D gravity rather than the annealed\ncoupling that is usually considered. We investigate the critical exponents in\nsuch a quenched ensemble and compare them with measurements on dynamical\n$\\phi^3$ graphs, flat lattices and a single fixed $\\phi^3$ graph.",
        "positive": "The topological susceptibility of two-dimensional $U(N)$ gauge theories: In this paper we study the topological susceptibility of two-dimensional\n$U(N)$ gauge theories. We provide explicit expressions for the partition\nfunction and the topological susceptibility at finite lattice spacing and\nfinite volume. We then examine the particularly simple case of the abelian\n$U(1)$ theory, the continuum limit, the infinite volume limit, and we finally\ndiscuss the large $N$ limit of our results."
    },
    {
        "anchor": "New results on the effective string corrections to the inter-quark\n  potential: We propose a new approach to the study of the inter-quark potential in\nLattice Gauge Theories. Instead of looking at the expectation value of Polyakov\nloop correlators we study the modifications induced in the chromoelectric flux\nby the presence of the Polyakov loops. In abelian LGTs, thanks to duality, this\nstudy can be performed in a very efficient way, allowing to reach high\nprecision with a reasonable CPU cost. The major advantage of this numerical\nstrategy is that it allows to eliminate the dominant effective string\ncorrection to the inter-quark potential (the Luscher term) thus giving an\nunique opportunity to test higher order corrections. Performing a set of\nsimulations in the 3d gauge Ising model we were thus able to precisely identify\nand measure both the quartic and the sextic effective string corrections to the\ninter-quark potential. While the quartic term perfectly agrees with the\nNambu-Goto one the sextic term is definitely different. Our result seems to\ndisagree with the recent proof by Aharony and Karzbrun of the universality of\nthe sextic correction. We discuss a few possible explanations of this\ndisagreement. The numerical approach described above can also be applied to the\nstudy of Wilson loops. In this case, the numerical results are precise enough\nto test the two-loop prediction of the Nambu-Goto action. The two-loop NG\nresult computed time ago by by Dietz and Filk is incompatible with the data;\nhowever, after correcting some mistakes in their expression, compatibility is\nrestored. The viability of a first-order, operatorial description of the Wilson\nloop is also pointed out.",
        "positive": "Comments on Lattice Calculations of Proton Spin Components: Comments on the recent lattice QCD calculations of the flavor-singlet axial\ncoupling constant $g_A^0$ and individual quark and gluon spin contributions to\nthe proton spin is given. I point out the physics learned from these\ncalculations as well as some of the lessons and pitfalls."
    },
    {
        "anchor": "A direct relation between confinement and chiral symmetry breaking in\n  temporally odd-number lattice QCD: In the lattice QCD formalism, we derive a gauge-invariant analytical relation\nconnecting the Polyakov loop and the Dirac modes on a temporally odd-number\nlattice, where the temporal lattice size is odd, with the normal (nontwisted)\nperiodic boundary condition. This analytical relation indicates that low-lying\nDirac modes have little contribution to the Polyakov loop. Using lattice QCD\nsimulations, we numerically confirm the analytical relation and the negligible\ncontribution of low-lying Dirac modes to the Polyakov loop at the quenched\nlevel, i.e., the Polyakov loop is almost unchanged by removing low-lying\nDirac-mode contribution from the QCD vacuum generated by lattice QCD in both\nconfinement and deconfinement phases. Thus, we conclude that there is no\none-to-one correspondence between confinement and chiral symmetry breaking in\nQCD. As a new method, modifying the Kogut-Susskind formalism, we develop a\nmethod for spin-diagonalizing the Dirac operator on the temporally odd-number\nlattice.",
        "positive": "Scattering lengths in SU(2) gauge theory with two fundamental fermions: We investigate non perturbatively scattering properties of Goldstone Bosons\nin an SU(2) gauge theory with two Wilson fermions in the fundamental\nrepresentation. Such a theory can be used to build extensions of the Standard\nModel that unifies Technicolor and pseudo Goldstone composite Higgs models. The\nleading order contribution to the scattering amplitude of Goldstone bosons at\nlow energy is given by the scattering lengths. In the context of technicolor\nextensions of the Standard Model the scattering lengths are constrained by WW\nscattering measurements. We first describe our setup and in particular the\nexpected chiral symmetry breaking pattern. We then discuss how to compute them\non the lattice and give preliminary results using finite size methods."
    },
    {
        "anchor": "Sign problem and Monte Carlo calculations beyond Lefschetz thimbles: We point out that Monte Carlo simulations of theories with severe sign\nproblems can be profitably performed over manifolds in complex space different\nfrom the one with fixed imaginary part of the action. We describe a family of\nsuch manifolds that interpolate between the tangent space at one critical\npoint, where the sign problem is milder compared to the real plane but in some\ncases still severe, and the union of relevant thimbles, where the sign problem\nis mild but a multimodal distribution function complicates the Monte Carlo\nsampling. We exemplify this approach using a simple 0 + 1 dimensional fermion\nmodel previously used on sign problem studies and show that it can solve the\nmodel for some parameter values where a solution using Lefshetz thimbles was\nelusive.",
        "positive": "Non-perturbative renormalization of kaon four-quark operators with\n  nf=2+1 Domain Wall fermions: We present our strategy and some preliminary results for the renormalization\nof four-quark operators relevant for kaon physics. We follow the\nnon-perturbative Rome-Southampton method, with both exceptional and\nnon-exceptional kinematics. We also implement momentum sources and twisted\nboundary conditions. We use an (almost) unitary setup: Domain-Wall valence on\nnf=2+1 Domain-Wall sea and Iwasaki gauge action, at two values of the lattice\nspacing corresponding to approximately 0.086 fm and 0.114 fm . The chiral\nproperties of these fermions play a crucial role in this compuation and are\nstudied in detail in this work."
    },
    {
        "anchor": "Variational approach to $N$-body interactions in finite volume: We explore variational approach to the finite-volume $N$-body problem. The\ngeneral formalism for N non-relativistic spinless particles interacting with\nperiodic pair-wise potentials yields N-body secular equations. The solutions\ndepend on the infinite-volume N-body wave functions. Given that the\ninfinite-volume N-body dynamics may be solved by the standard Faddeev approach,\nthe variational N-body formalism can provide a convenient numerical framework\nfor finding discrete energy spectra in periodic lattice structures.",
        "positive": "Hadron Spectroscopy and Resonances: Review: I review recent results on hadron spectroscopy using lattice QCD. In light of\nthe discoveries in heavy baryon sector at LHCb over the past few years, lattice\ncalculations in this regard are emphasized. Investigations on light baryon,\nheavy-heavy and heavy-light meson resonances are also discussed."
    },
    {
        "anchor": "Monte Carlo simulations of 4d simplicial quantum gravity: Dynamical triangulations of four-dimensional Euclidean quantum gravity give\nrise to an interesting, numerically accessible model of quantum gravity. We\ngive a simple introduction to the model and discuss two particularly important\nissues. One is that contrary to recent claims there is strong analytical and\nnumerical evidence for the existence of an exponential bound that makes the\npartition function well-defined. The other is that there may be an ambiguity in\nthe choice of the measure of the discrete model which could even lead to the\nexistence of different universality classes.",
        "positive": "Renormalization Group Flow of SU(3) Gauge Theory: We calculate numerically the renormalization group (RG) flow of lattice QCD\nin two-coupling space, $(\\beta_{1\\times 1},\\beta_{1\\times 2})$. This is the\nfirst explicit calculation of the RG flow of SU(3) gauge theory. From the RG\nflow,a renormalized trajectory (RT) is revealed. Its behavior is consistent\nwith the strong coupling expansion near the high-temperature fixed point.\nActions with $(\\beta_{1\\times 1},\\beta_{1\\times 2})$ are studied; the lattice\nspacing is evaluated by measuring the string tension from the heavy quark\npotential. Recovery of the rotational symmetry is studied as a function of the\nratio $\\beta_{1\\times 2} / \\beta_{1\\times 1}$."
    },
    {
        "anchor": "Non-perturbative renormalization of tensor currents: strategy and\n  results for $N_f = 0$ and $N_f = 2$ QCD: Tensor currents are the only quark bilinear operators lacking a\nnon-perturbative determination of their renormalisation group (RG) running\nbetween hadronic and electroweak scales. We develop the setup to carry out the\ncomputation in lattice QCD via standard recursive finite-size scaling\ntechniques, and provide results for the RG running of tensor currents in $N_f =\n0$ and $N_f = 2$ QCD in the continuum for various Schr\u007f\\\"odinger Functional\nschemes. The matching factors between bare and renormalisation group invariant\ncurrents are also determined for a range of values of the lattice spacing\nrelevant for large-volume simulations, thus enabling a fully non-perturbative\nrenormalization of physical amplitudes mediated by tensor currents.",
        "positive": "Lattice Regularization and Symmetries: Finding the relation between the symmetry transformations in the continuum\nand on the lattice might be a nontrivial task as illustrated by the history of\nchiral symmetry. Lattice actions induced by a renormalization group procedure\ninherit all symmetries of the continuum theory. We give a general procedure\nwhich gives the corresponding symmetry transformations on the lattice."
    },
    {
        "anchor": "Proton Spin Structure from Lattice QCD: A lattice QCD calculation of the proton matrix element of the flavor singlet\naxial-vector current is reported. Both the connected and disconnected\ncontributions are calculated, for the latter employing the variant method of\nwall source without gauge fixing. From simulations in quenched QCD with the\nWilson quark action on a $16^3\\times 20$ lattice at $\\beta=5.7$ (the lattice\nspacing $a\\approx 0.14$fm), we find $\\Delta\\Sigma=\\Delta u+\\Delta d+\\Delta\ns=+0.638(54)-0.347(46)-0.109(30) = +0.18(10)$ with the disconnected\ncontribution to $\\Delta u$ and $\\Delta d$ equal to $-0.119(44)$, which is\nreasonably consistent with the experiment.",
        "positive": "Color dependence of the topological susceptibility in Yang-Mills\n  theories: For Yang-Mills theories in four dimensions, we propose to rescale the ratio\nbetween topological susceptibility and string tension squared in a universal\nway, dependent only on group factors. We apply this suggestion to $SU(N_c)$ and\n$Sp(N_c)$ groups, and compare lattice measurements performed by several\nindependent collaborations. We show that the two sequences of (rescaled)\nnumerical results in these two families of groups are compatible with each\nother. We hence perform a combined fit, and extrapolate to the common\nlarge-$N_c$ limit."
    },
    {
        "anchor": "Spectrum of 4d N=1 SYM on the lattice with light dynamical Wilson\n  gluinos: We perform Monte Carlo investigations of the 4d ${\\cal N}=1$ supersymmetric\nYang-Mills (SYM) theory on the lattice with dynamical gluinos in the adjoint\nrepresentation of the SU(2) gauge group. Our aim is to determine the mass\nspectrum of the low-lying bound states which is expected to be organised in\nsupermultiplets in the infinite volume continuum limit. For this purpose we\nperform simulations on large lattices, up to an extension $L/r_0 \\simeq 6$\nwhere $r_0 \\simeq 0.5 \\rm fm$ is the Sommer scale parameter. We apply improved\nlattice actions: tree-level improved Symanzik (tlSym) gauge action and in the\nlater runs a Stout-smeared Wilson fermion action. The gauge configuration\nsamples are prepared by the Two-Step Polynomial Hybrid Monte Carlo (TS-PHMC)\nupdate algorithm.",
        "positive": "Parton distribution functions on the lattice and in the continuum: Ioffe-time distributions, which are functions of the Ioffe-time $\\nu$, are\nthe Fourier transforms of parton distribution functions with respect to the\nmomentum fraction variable $x$. These distributions can be obtained from\nsuitable equal time, quark bilinear hadronic matrix elements which can be\ncalculated from first principles in lattice QCD, as it has been recently\nargued. In this talk I present the first numerical calculation of the\nIoffe-time distributions of the nucleon in the quenched approximation."
    },
    {
        "anchor": "Improved bilinears in lattice QCD with non-degenerate quarks: We describe the extension of the improvement program for bilinear operators\ncomposed of Wilson fermions to non-degenerate dynamical quarks. We consider\ntwo, three and four flavors, and both flavor non-singlet and singlet operators.\nWe find that there are many more improvement coefficients than with degenerate\nquarks, but that, for three or four flavors, nearly all can be determined by\nenforcing vector and axial Ward identities. The situation is worse for two\nflavors, where many more coefficients remain undetermined.",
        "positive": "Axial U(1) symmetry at finite temperature with M\u00f6bius domain-wall\n  fermions: We investigate the axial $U(1)$ symmetry restoration at finite temperature in\ntwo flavor QCD. We employ the M\\\"obius domain-wall formalism that is designed\nto achieve good chiral symmetry. We show the measurements of a difference of\nmeson susceptibilities, sensitive to the $U(1)_A$ symmetry breaking. The signal\nis dominated by zero and near-zero modes. By reweighting the measure to that of\noverlap fermions we find a suppression of the $U(1)_A$ breaking effects above\nthe chiral transition temperature."
    },
    {
        "anchor": "Tests of hadronic vacuum polarization fits for the muon anomalous\n  magnetic moment: Using experimental spectral data for hadronic tau decays from the OPAL\nexperiment, supplemented by a phenomenologically successful parameterization\nfor the high-s region not covered by the data, we construct a physically\nconstrained model of the isospin-one vector-channel polarization function.\nHaving such a model as a function of Euclidean momentum Q^2 allows us to\nexplore the systematic error associated with fits to the Q^2 dependence of\nlattice data for the hadronic electromagnetic current polarization function\nwhich have been used in attempts to compute the leading order hadronic\ncontribution, a_\\mu^HLO, to the muon anomalous magnetic moment. In contrast to\nrecent claims made in the literature, we find that a final error in this\nquantity of the order of a few percent does not appear possible with current\nlattice data, given the present lack of precision in the determination of the\nvacuum polarization at low Q^2. We also find that fits to the vacuum\npolarization using fit functions based on Vector Meson Dominance are\nunreliable, in that the fit error on a_\\mu^HLO is typically much smaller than\nthe difference between the value obtained from the fit and the exact model\nvalue. The use of a sequence of Pade approximants known to converge to the true\nvacuum polarization appears to represent a more promising approach.",
        "positive": "A New Type of Lattice Gauge Theory through Self-adjoint Extensions: A generalization of Wilsonian lattice gauge theory may be obtained by\nconsidering the possible self-adjoint extensions of the electric field operator\nin the Hamiltonian formalism. In the special case of 3D $\\mathrm{U}(1)$ gauge\ntheory these are parametrised by a phase $\\theta$, and the ordinary Wilson\ntheory is recovered for $\\theta=0$. We consider the case $\\theta=\\pi$, which,\nupon dualization, turns into a theory of staggered integer and half-integer\nheight variables. We investigate order parameters for the breaking of the\nrelevant symmetries, and thus study the phase diagram of the theory, which\nshows evidence of a broken $\\mathbb{Z}_2$ symmetry in the continuum limit, in\ncontrast to the ordinary theory."
    },
    {
        "anchor": "Eigenstate Thermalization in 2+1 dimensional SU(2) Lattice Gauge Theory: We present preliminary numerical evidence for the hypothesis that the\nHamiltonian SU(2) gauge theory discretized on a lattice obeys the Eigenstate\nThermalization Hypothesis (ETH). To do so we study three approximations: (a) a\nlinear plaquette chain in a reduced Hilbert space limiting the electric field\nbasis to $j=0,\\frac{1}{2}$ , (b) a two-dimensional honeycomb lattice with\nperiodic or closed boundary condition and the same Hilbert space constraint,\nand (c) a chain of only three plaquettes but such a sufficiently large electric\nfield Hilbert space ($j \\leq \\frac{7}{2})$ that convergence of all energy\neigenvalues in the analyzed energy window is observed. While an unconstrained\nHilbert space is required to reach the continuum limit of SU(2) gauge theory,\nnumerical resource constraints do not permit us to realize this requirement for\nall values of the coupling constant and large lattices. In each of the three\nstudied cases we check first for random matrix theory (RMT) behavior in the\neigenenergy spectrum and then analyze the diagonal as well as the off-diagonal\nmatrix elements between energy eigenstates for a few operators. Within current\nuncertainties all results for (a), (b) and (c) agree with ETH predictions.\nFurthermore, we find the off-diagonal matrix elements of the electric energy\noperator exhibit RMT behavior in frequency windows that are small enough in (b)\nand (c). To unambiguously establish ETH behavior and determine for which class\nof operators it applies, an extension of our investigations is necessary.",
        "positive": "Interplay of Monopoles and P-Vortices: We show that P-Vortices in the confinement phase of SU(2) lattice gauge\ntheory form one large percolating (infrared) cluster and a number of small\n(ultraviolet) clusters. We discuss the interrelation of clusters of monopoles\nin the maximal Abelian projection with clusters of P-vortices. To extract\nP-vortices we use both direct and indirect central projections and find\nqualitatively similar results."
    },
    {
        "anchor": "On topological properties of vacuum defects in lattice Yang-Mills\n  theories: We study correlations between low-lying modes of the overlap Dirac operator\nand vacuum defects, center vortices and three-dimensional volumes, in lattice\nSU(2) gluodynamics. The low-lying modes are apparently sensitive to topological\nproperties of the underlying gluon field configurations while the vacuum\ndefects are crucial for the confinement. We find distinct positive correlation\nin both cases. In case of vortices the correlation is stronger.",
        "positive": "Thermal dilepton rates and electrical conductivity of the QGP from the\n  lattice: We investigate the temperature dependence of the thermal dilepton rate and\nthe electrical conductivity of the gluon plasma at temperatures of $1.1T_c$,\n$1.3T_c$ and $1.5T_c$ in quenched QCD. Making use of non-perturbatively\nclover-improved Wilson valence quarks allows for a clean extrapolation of the\nvector meson correlation function to the continuum limit. We found that the\nvector correlation function divided by $T^3$ is almost temperature independent\nin the current temperature window. The spectral functions are obtained by\n$\\chi^2$ fitting of phenomenologically inspired Ans\\\"atze for the spectral\nfunction to the continuum extrapolated correlator data, where the correlations\nbetween the data points have been included. Systematic uncertainties arising\nfrom varying the Ans\\\"atze motivated from strong coupling theory as well as\nperturbation theory are discussed and estimated. We found that the electrical\nconductivity of the hot medium, related to the slope of the vector spectral\nfunction at zero frequency and momentum, is $0.2C_{em}\\lesssim\n\\sigma/T\\lesssim0.7C_{em}$ for $T=1.1T_c$ and $0.2C_{em}\\lesssim\n\\sigma/T\\lesssim0.4C_{em}$ for the higher temperatures. The dilepton rates and\nsoft photon rates, resulting from the obtained spectral functions, show no\nsignificant temperature dependence, either."
    },
    {
        "anchor": "Towards a perfect fixed point action for SU(3) gauge theory: We present an overview of the construction and testing of actions for SU(3)\ngauge theory which are approximate fixed points of renormalization group\nequations (at $\\beta\\rightarrow \\infty$). Such actions are candidates for use\nin numerical simulations on coarse lattices.",
        "positive": "S-parameter and vector decay constant in QCD with eight fundamental\n  fermions: SU(3) gauge theory with eight massless fundamental fermions seems to be near\nthe conformal boundary, and is a candidate theory of walking technicolor. Along\nthe series of study by LatKMI collaboration using HISQ fermions, S-parameter\nand vector decay constant, which provide important constraints in the model of\nelectroweak symmetry breaking, are calculated for this theory. Use of various\nvolumes allows a systematic investigation of finite volume effects. A strong\nsensitivity of the S-parameter to the volume is found."
    },
    {
        "anchor": "On the phase of quark determinant in lattice QCD with finite chemical\n  potential: We investigate the phase of the quark determinant with finite chemical\npotential in lattice QCD using both analytic and numerical methods. Applying\nthe winding number expansion and the hopping parameter expansion to the\nlogarithm of the determinant, we show that the absolute value of the phase has\nan upper bound that grows with the spatial volume but decreases exponentially\nwith an increase in the temporal extent of the lattice. This analytic but\napproximate result is confirmed with a numerical study in four-flavor QCD in\nwhich the phase is calculated exactly. Since the phase is well controlled on\nlattices with larger time extents, we try the phase reweighting method in a\nregion beyond $\\mu/T=1$ where the Taylor expansion method cannot be applied.\nWorking in four-flavor QCD, we find a first-order like behavior on a $6^3\\times\n4$ lattice at $\\mu /T\\approx 0.8$ which was previously observed by Kentucky\ngroup with the canonical method. We also show that the winding number expansion\nhas a nice convergence property beyond $\\mu/T=1$. We expect that this expansion\nis useful to study the high density region of the QCD phase diagram at low\ntemperatures.",
        "positive": "Perturbative Renormalization Factors of Quark Bilinear Operators for\n  Domain-wall QCD: We calculate one-loop renormalization factors of bilinear operators made of\nphysical quark fields for domain-wall QCD. We find that finite parts of such\nrenormalization factors have reasonable values at 1-loop except an overlap\nfactor between the physical quark field and the zero mode in the theory. We\npoint out that the 1-loop estimate of overall renormalization factors becomes\nunreliable at the coupling where numerical simulations are currently performed,\ndue to the presence of this overlap factor. We show that this problem\ndisappears if the mean-field improved perturbation theory is employed for\nrenormalization factors."
    },
    {
        "anchor": "Excited-state contamination in nucleon correlators from chiral\n  perturbation theory: Techniques to compute hadron properties from lattice QCD rely upon the limit\nof long time separation. For baryons, the signal-to-noise problem often\nrestricts one to time separations that are not ideally long, and for which\ncouplings to excited states can obstruct the isolation of ground-state baryon\nproperties. We consider excited-state contamination in nucleon two- and\nthree-point functions. Using chiral perturbation theory, we determine couplings\nto pion-nucleon and pion-delta excited states. In two-point functions, these\ncontributions are small, in accordance with general properties of the spectral\nweights on a torus. For the axial-current correlation function in the nucleon,\nthe sign of excited-state contributions suggests overestimation of the nucleon\naxial charge. Thus contamination from pion-nucleon excited states will not\nlikely explain the trend in lattice QCD data.",
        "positive": "Near the sill of the conformal window: gauge theories with fermions in\n  two-index representations: We apply Schroedinger functional methods to two gauge theories with fermions\nin two-index representations: the SU(3) theory with Nf=2 adjoint fermions, and\nthe SU(4) theory with Nf=6 fermions in the two-index antisymmetric\nrepresentation. Each theory is believed to lie near the bottom of the conformal\nwindow for its respective representation. In the SU(3) theory we find a small\nbeta function in strong coupling but we cannot confirm or rule out an infrared\nfixed point. In the SU(4) theory we find a hint of walking - a beta function\nthat approaches the axis and then turns away from it. In both theories the mass\nanomalous dimension remains small even at the strongest couplings, much like\nthe theories with fermions in the two-index symmetric representation\ninvestigated earlier."
    },
    {
        "anchor": "Embedded Topological Defects in Hot Electroweak Theory: a Lattice Study: We study the properties of Nambu monopoles and Z-vortices in the 3D lattice\nSU(2) Higgs theory which represents the Standard Model at high temperature. We\nshow that the densities of the Nambu monopoles and the Z-vortices are O(1) in\nthe symmetric phase and generically small in the Higgs phase. Near to the\ncritical Higgs mass and in the vicinity of the phase transition the densities\nare no more negligible in the broken phase. The percolation probability of the\nZ-vortex lines is found as a new disorder parameter for this phase transition.\nWe conclude that the transition to the symmetric phase is accompanied by\nZ-vortex condensation. Simulations comparing elementary and extended vortices\nand monopoles at different \\beta_G values, aiming to show that the density of\nvortices and monopoles of fixed physical size might have a well-defined\ncontinuum limit, gives encouraging but so far inconclusive results.",
        "positive": "Real-time quantum calculations of phase shifts using wave packet time\n  delays: We present a method to extract the phase shift of a scattering process using\nthe real-time evolution in the early and intermediate stages of the collision\nin order to estimate the time delay of a wave packet. This procedure is\nconvenient when using noisy quantum computers for which the asymptotic\nout-state behavior is unreachable. We demonstrate that the challenging Fourier\ntransforms involved in the state preparation and measurements can be\nimplemented in $1+1$ dimensions with current trapped ion devices and IBM\nquantum computers. We compare quantum computation of the time delays obtained\nin the one-particle quantum mechanics limit and the scalable quantum field\ntheory formulation with accurate numerical results. We discuss the finite\nvolume effects in the Wigner formula connecting time delays to phase shifts.\nThe results reported involve two- and four-qubit calculations, and we discuss\nthe possibility of larger scale computations in the near future."
    },
    {
        "anchor": "Role of chiral symmetry in the nucleon excitation spectrum: The origin of the low-lying nature of the $N$*(1440), or Roper resonance, has\nbeen the subject of significant interest for many years, including several\ninvestigations using lattice QCD. The majority of lattice studies have not\nobserved a low-lying excited state energy level in the region of the Roper\nresonance. However, it has been claimed that chiral symmetry could play an\nimportant role in our understanding of this resonance. The purpose of this\nstudy is to systematically examine the role of chiral symmetry in the low-lying\nnucleon spectrum by directly comparing the clover and overlap fermion actions.\nTo ensure any differences in results are attributable to the choice of fermion\naction, simulations are performed on the same set of gauge field configurations\nat matched pion masses. Correlation matrix techniques are employed to determine\nthe excitation energy of the first positive-parity excited state for each\naction. The clover and overlap actions show a remarkable level of agreement. We\ndo not find any evidence that fermion action chiral symmetry plays a\nsignificant role in understanding the Roper resonance on the lattice.",
        "positive": "New results from APE with non-perturbatively improved Wilson fermions: We present the results for light hadron spectrum, decay constants and the\nquark masses obtained with non-perturbatively improved Wilson fermions. We also\ngive our preliminary results for the heavy-light decay constants."
    },
    {
        "anchor": "Lattice investigation of the tetraquark candidates a0(980) and kappa: It is a long discussed issue whether light scalar mesons have sizeable\nfour-quark components. We present an exploratory study of this question using\nN_f=2+1+1 twisted mass lattice QCD. A mixed action approach ignoring\ndisconnected contributions is used to calculate correlator matrices consisting\nof mesonic molecule, diquark-antidiquark and two-meson interpolating operators\nwith quantum numbers of the scalar mesons a0(980) (1(0^++)) and kappa\n(1/2(0+)). The correlation matrices are analyzed by solving the generalized\neigenvalue problem. The theoretically expected free two-particle scattering\nstates are identified, while no additional low lying states are observed. We do\nnot observe indications for bound four-quark states in the channels\ninvestigated.",
        "positive": "Approach to $K\\to \\ell\u03bd_\\ell \\ell'^+ \\ell'^-$ decay width on lattice: Lattice QCD plays an increasing role in reducing theoretical uncertainties in\nkaon decays. Here we focus on kaon decay channels $K\\to \\ell\\nu_\\ell \\ell'^+\n\\ell'^-$, which are closely related to radiative kaon decays since the lepton\npairs $\\ell'^+ \\ell'^-$ come from virtual photon emission: $K\\to \\ell\\nu_\\ell\n\\gamma^* \\to \\ell\\nu_\\ell \\ell'^+ \\ell'^-$. Compared with real photon emission,\nthese channels involve more complicated form factors due to the off-shell\nphoton with possible large momentum transfer, which causes a challenge to\nlattice-QCD studies. In this work, we introduce a lattice calculation procedure\nfor their decay width, which can avoid parameterization of form factors. The\nsystematic errors in our method are found to be controllable. Infinite volume\nreconstruction method is adopted to remove the temporal truncation effects and\nreduce finite volume effects from kaon intermediate state. This approach sets\nup a bridge between lattice QCD calculation and experimental measurement of\ndecay width."
    },
    {
        "anchor": "Quark Model from Lattice QCD: We study the valence approximation in lattice QCD of hadrons where the cloud\nquarks and antiquarks are deleted by truncating the backward time propagation\n(Z graphs) in the connected insertions. Whereas, the sea quarks are eliminated\nvia the quenched approximation and in the disconnected insertions. It is shown\nthat the ratios of isovector to isoscalar matrix elements in the nucleon\nreproduce the SU(6) quark model predictions in a lattice QCD calculation. We\nalso discuss how the hadron masses are affected.",
        "positive": "Numerical Study of Gluon Propagator and Confinement Scenario in Minimal\n  Coulomb Gauge: We present numerical results in SU(2) lattice gauge theory for the\nspace-space and time-time components of the gluon propagator at equal time in\nthe minimal Coulomb gauge. It is found that the equal-time would-be physical\n3-dimensionally transverse gluon propagator $D^{tr}(\\vec{k})$ vanishes at\n$\\vec{k} = 0$ when extrapolated to infinite lattice volume, whereas the\ninstantaneous color-Coulomb potential $D_{44}(\\vec{k})$ is strongly enhanced at\n$\\vec{k} = 0$. This has a natural interpretation in a confinement scenario in\nwhich the would-be physical gluons leave the physical spectrum while the\nlong-range Coulomb force confines color. Gribov's formula $D^{tr}(\\vec{k}) =\n(|\\vec{k}|/2)[(\\vec{k}^2)^2 + M^4]^{1/2}$ provides an excellent fit to our data\nfor the 3-dimensionally transverse equal-time gluon propagator\n$D^{tr}(\\vec{k})$ for relevant values of $\\vec{k}$."
    },
    {
        "anchor": "Pseudoscalar transition form factors and the hadronic light-by-light\n  contribution to the muon $g-2$: We report on our progress toward the computation of the $\\pi^0$, $\\eta$ and\n$\\eta^{\\prime}$ transition form factors using staggered quarks on $N_f=2+1+1$\ngauge ensembles generated by the Budapest-Marseille-Wuppertal collaboration.\nThese form factors are essential ingredients to evaluate the pseudoscalar-pole\ncontributions to the hadronic light-by-light scattering in the muon $g-2$.\nPreliminary results for the pseudoscalar-pole contributions are presented, at\nfinite lattice spacing, for all three light mesons.",
        "positive": "Non-perturbative volume-reduction of large-N QCD with adjoint fermions: We use nonperturbative lattice techniques to study the volume-reduced\n\"Eguchi-Kawai\" version of four-dimensional large-N QCD with a single adjoint\nDirac fermion. We explore the phase diagram of this single-site theory in the\nspace of quark mass and gauge coupling using Wilson fermions for a number of\ncolors in the range 8 <= N <= 15. Our evidence suggests that these values of N\nare large enough to determine the nature of the phase diagram for N-->oo. We\nidentify the region in the parameter space where the (Z_N)^4 center-symmetry is\nintact. According to previous theoretical work using the orbifolding paradigm,\nand assuming that translation invariance is not spontaneously broken in the\ninfinite-volume theory, in this region volume reduction holds: the single-site\nand infinite-volume theories become equivalent when N-->oo. We find strong\nevidence that this region includes both light and heavy quarks (with masses\nthat are at the cutoff scale), and our results are consistent with this region\nextending towards the continuum limit. We also compare the action density and\nthe eigenvalue density of the overlap Dirac operator in the fundamental\nrepresentation with those obtained in large-N pure-gauge theory."
    },
    {
        "anchor": "Planar Thirring Model in the U(2$N$)-symmetric limit: I review the Thirring model in 2+1$d$ dimensions, focussing in particular on\npossible strongly-interacting UV-stable fixed points of the renormalisation\ngroup, corresponding to a continuous phase transition where a U($2N$) global\nsymmetry spontaneously breaks to U($N)\\otimes$U($N$). Since there is no small\nparameter in play, a systematic non-perturbative approach such as numerical\nsimulation of lattice field theory is mandated. I compare and contrast various\nformulations, paying particular attention to models formulated with either\nstaggered or domain wall lattice fermions. Domain wall fermions, which\nfaithfully capture U($2N$) symmetry in the limit of wall separation\n$L_s\\to\\infty$, predict a critical flavor number $1<N_c<2$.",
        "positive": "The glueball spectrum of SU(3) gauge theory in 3+1 dimension: We calculate the low-lying glueball spectrum of the SU(3) lattice gauge\ntheory in 3+1 dimensions for the range of beta up to beta=6.50 using the\nstandard plaquette action. We do so for states in all the representations R of\nthe cubic rotation group, and for both values of parity P and charge\nconjugation C. We extrapolate these results to the continuum limit of the\ntheory using the confining string tension as our energy scale. We also present\nour results in units of the r0 scale and, from that, in terms of physical `GeV'\nunits. For a number of these states we are able to identify their continuum\nspins J with very little ambiguity. We also calculate the topological charge Q\nof the lattice gauge fields so as to show that we have sufficient ergodicity\nthroughout our range of beta, and we calculate the multiplicative\nrenormalisation of Q as a function of beta. We also obtain the continuum limit\nof the SU(3) topological susceptibility."
    },
    {
        "anchor": "The gluon propagator in Coulomb gauge from the lattice: We show that in the lattice Hamiltonian limit the static transverse\npropagator $D(|\\vec{p}|)\\propto\\int d p_0 D(|\\vec{p}|,p_0)$ satisfies\nmultiplicative renormalizability. We give a procedure to calculate\n$D(|\\vec{p}|)$ on available lattices at finite temporal spacing. The result\nagrees at all momenta with the Gribov formula $D(|\\vec{p}|)\\propto(|\\vec{p}|^2+\nM^4 |\\vec{p}|^{-2})^{-{1/2}}$, with $M=0.88(1) {\\rm GeV} \\simeq 2\n\\sqrt{\\sigma}$.",
        "positive": "Chiral properties of dynamical Wilson fermions: We consider two-flavor QCD in the lattice regularization with improved Wilson\nfermions. In this formulation chiral symmetry is explicitly broken at order a\nand hence the isovector axial currents require improvement as well as a finite\nrenormalization if they are to satisfy continuum Ward--Takahashi identities up\nto small lattice corrections of O(a^2). Algorithmic difficulties at coarse\nlattice spacings, where HMC suffers from a distorted Dirac spectrum, are\ndiscussed. This is shown to be a cutoff effect, which disappears rapidly as the\nlattice spacing is decreased. An alternative algorithm, the polynomial hybrid\nMonte Carlo algorithm, is found to perform significantly better in the presence\nof exceptionally small eigenvalues. Extending previously used methods both the\nimprovement and the renormalization of the axial current are implemented\nnon--perturbatively in terms of correlation functions formulated in the\nframework of the Schroedinger functional. In both cases this is achieved by\nenforcing continuum Ward identities at finite lattice spacing. Together, this\nrestores the isovector chiral symmetry to quadratic order in the lattice\nspacing. With little additional effort the normalization factor of the local\nvector current is also obtained."
    },
    {
        "anchor": "QCDGPU: open-source package for Monte Carlo lattice simulations on\n  OpenCL-compatible multi-GPU systems: The multi-GPU open-source package QCDGPU for lattice Monte Carlo simulations\nof pure SU(N) gluodynamics in external magnetic field at finite temperature and\nO(N) model is developed. The code is implemented in OpenCL, tested on AMD and\nNVIDIA GPUs, AMD and Intel CPUs and may run on other OpenCL-compatible devices.\nThe package contains minimal external library dependencies and is OS\nplatform-independent. It is optimized for heterogeneous computing due to the\npossibility of dividing the lattice into non-equivalent parts to hide the\ndifference in performances of the devices used. QCDGPU has client-server part\nfor distributed simulations. The package is designed to produce lattice gauge\nconfigurations as well as to analyze previously generated ones. QCDGPU may be\nexecuted in fault-tolerant mode. Monte Carlo procedure core is based on PRNGCL\nlibrary for pseudo-random numbers generation on OpenCL-compatible devices,\nwhich contains several most popular pseudo-random number generators.",
        "positive": "Glueballs on a transverse lattice: Accurate non-perturbative calculations of glueballs are performed using\nlight-front quantised SU(N) gauge theory, to leading order of the 1/N\nexpansion. Based on early work of Bardeen and Pearson, disordered\ngauge-covariant link variables M on a coarse transverse lattice are used to\napproximate the physical gauge degrees of freedom. Simple energetics imply\nthat, at lattice spacings of order the inverse QCD scale, the effective\nlight-front Hamiltonian can be expanded in gauge-invariant powers of M: a\ncolour-dielectric expansion. This leads to a self-consistent constituent\nstructure of boundstates. We fix the couplings of this expansion by optimising\nLorentz covariance of low-energy eigenfunctions. To lowest non-trivial order of\nthe expansion, we have found a one-parameter trajectory of couplings that\nenhances Lorentz covariance. On this trajectory the masses of nearly-covariant\nglueball states exhibit approximate scaling, having values consistent with\nlarge-N extrapolations of continuum results from other methods. There is very\nlittle variation with N in pure Yang-Mills theory: the lightest glueball mass\nchanges by only a few percent between SU(3) and SU(infinity). The corresponding\nlight-front wavefunctions show an unconventional structure. We also examine\nrestoration of rotational invariance in the heavy-source potential."
    },
    {
        "anchor": "Complex Langevin simulations of a finite density matrix model for QCD: We study a random matrix model for QCD at finite density via complex Langevin\ndynamics. This model has a phase transition to a phase with nonzero baryon\ndensity. We study the convergence of the algorithm as a function of the quark\nmass and the chemical potential and focus on two main observables: the baryon\ndensity and the chiral condensate. For simulations close to the chiral limit,\nthe algorithm has wrong convergence properties when the quark mass is in the\nspectral domain of the Dirac operator. A possible solution of this problem is\ndiscussed.",
        "positive": "Density of states method for the Z(3) spin model: We apply the density of states approach to the Z(3) spin model with a\nchemical potential mu. For determining the density of states we use restricted\nMonte Carlo simulations on small intervals of the variable for the density. In\neach interval we probe the response of the system to the variation of a free\nparameter in the Boltzmann factor. This response is a known function which we\nfit to the Monte Carlo data and the parameters of the density are obtained from\nthat fit (functional fit approch; FFA). We evaluate observables related to the\nparticle number and the particle number susceptibility, as well as the free\nenergy. We find that for a surprisingly large range of mu the results from the\nFFA agree very well with the results from a reference simulation in the dual\nformulation of the Z(3) spin model which is free of the complex action problem."
    },
    {
        "anchor": "Baryon currents in the C-broken phase of QCD: In a space with some sufficiently small compact dimension (with non-trivial\ncycles) and with periodic boundary conditions for the fermions, the charge\nconjugation (C), spatial parity (P), time reversal (T) and CPT symmetries are\nspontaneously broken in QCD. We have investigated what are the physical\nconsequences of the breaking of these discrete symmetries, that is what local\nobservables can be used to detect it. We show that the breaking induces the\ngeneration of baryon currents, propagating along the compact dimensions.",
        "positive": "Analytic Estimate of the Order Parameter for Magnetic Charge\n  Condensation in QCD: The order parameter for monopole condensation is computed in terms of gauge\ninvariant field strength correlators. Important properties emerge of the\ncorrelators in the confined phase, which could not be extracted by existing\nnumerical determinations on the lattice."
    },
    {
        "anchor": "Computing the Adler function from the vacuum polarization function: We use a lattice determination of the hadronic vacuum polarization tensor to\nstudy the associated Ward identities and compute the Adler function. The vacuum\npolarization tensor is computed from a combination of point-split and local\nvector currents, using two flavours of O($a$)-improved Wilson fermions.\nPartially twisted boundary conditions are employed to obtain a fine momentum\nresolution. The modifications of the Ward identities by lattice artifacts and\nby the use of twisted boundary conditions are monitored. We determine the Adler\nfunction from the derivative of the vacuum polarization function over a large\nregion of momentum transfer $q^2$. As a first account of systematic effects, a\ncontinuum limit scaling analysis is performed in the large $q^2$ regime.",
        "positive": "Finite size effects in the presence of a chemical potential: A study in\n  the classical non-linear O(2) sigma-model: In the presence of a chemical potential, the physics of level crossings leads\nto singularities at zero temperature, even when the spatial volume is finite.\nThese singularities are smoothed out at a finite temperature but leave behind\nnon-trivial finite size effects which must be understood in order to extract\nthermodynamic quantities using Monte Carlo methods, particularly close to\ncritical points. We illustrate some of these issues using the classical\nnon-linear O(2) sigma model with a coupling $\\beta$ and chemical potential\n$\\mu$ on a 2+1 dimensional Euclidean lattice. In the conventional formulation\nthis model suffers from a sign problem at non-zero chemical potential and hence\ncannot be studied with the Wolff cluster algorithm. However, when formulated in\nterms of world-line of particles, the sign problem is absent and the model can\nbe studied efficiently with the \"worm algorithm\". Using this method we study\nthe finite size effects that arise due to the chemical potential and develop an\neffective quantum mechanical approach to capture the effects. As a side result\nwe obtain energy levels of up to four particles as a function of the box size\nand uncover a part of the phase diagram in the $(\\beta,\\mu)$ plane."
    },
    {
        "anchor": "Effective Actions for the SU(2) Confinement-Deconfinement Phase\n  Transition: We compare different Polyakov loop actions yielding effective descriptions of\nfinite-temperature SU(2) Yang-Mills theory on the lattice. The actions are\nmotivated by a simultaneous strong-coupling and character expansion obeying\ncenter symmetry and include both Ising and Ginzburg-Landau type models. To keep\nthings simple we limit ourselves to nearest-neighbor interactions. Some\ntruncations involving the most relevant characters are studied within a novel\nmean-field approximation. Using inverse Monte-Carlo techniques based on exact\ngeometrical Schwinger-Dyson equations we determine the effective couplings of\nthe Polyakov loop actions. Monte-Carlo simulations of these actions reveal that\nthe mean-field analysis is a fairly good guide to the physics involved. Our\nPolyakov loop actions reproduce standard Yang-Mills observables well up to\nlimitations due to the nearest-neighbor approximation.",
        "positive": "Constructing static quark-anti-quark creation operators from Laplacian\n  eigenmodes: We investigate static quark anti-quark operators based on trial states formed\nfrom eigenvectors of the covariant three-dimensional lattice Laplace operator.\nWe test the method by computing the static quark-anti-quark potential and\ncomparing results to standard Wilson loop measurements. The new method is\nefficient not only for on-axis, but also for many off-axis quark-anti-quark\nseparations when a fine spatial resolution is required. We further improve the\nground-state overlap by using multiple eigenvector pairs, weighted with\nGaussian profile functions of the eigenvalues, providing a variational basis.\nThe method presented here can be applied to potential functions for all\npossible excitations of a gluonic string with fixed ends, hybrid or tetra-quark\npotentials, as well as static-light systems and allows visualization of the\nspatial distribution of the Laplace trial states."
    },
    {
        "anchor": "Hybrid mesons from anisotropic lattice QCD with the clover and improved\n  gauge actions: We study hybrid mesons from the clover and improved gauge actions at\n$\\beta=2.6$ on the anisotropic $12^3\\times36$ lattice using our PC cluster. We\nestimate the mass of $1^{-+}$ light quark hybrid as well as the mass of the\ncharmonium hybrid. The improvement of both quark and gluonic actions, first\napplied to the hybrid mesons, is shown to be more efficient in reducing the\nlattice spacing and finite volume errors.",
        "positive": "Finite Volume corrections to $< x>_{u\\pm d}$: In this paper we calculate the full one-loop finite volume corrections to the\nquantities $< x >_{u\\pm d}$ within the framework of two-flavor baryon chiral\nperturbation theory and show estimates of these effects for the leading\none-loop corrections based on fits carried out in previously published works."
    },
    {
        "anchor": "Adjoint modes as probes of gauge field structure: We show how zero-modes and quasi-zero-modes of the Dirac operator in the\nadjoint representation can be used to construct an estimate of the action\ndensity distribution of a pure gauge field theory, which is less sensitive to\nthe ultraviolet fluctuations of the field. This can be used to trace the\ntopological structures present in the vacuum. The construction relies on the\nspecial properties satisfied by the supersymmetric zero-modes.",
        "positive": "The finite temperature transition for 3-flavour lattice QCD at finite\n  isospin density: We simulate 3-flavour lattice QCD with a small chemical potential $\\mu_I$ for\nisospin, at temperatures close to the finite temperature transition. Using\nquark masses just above the critical mass for zero chemical potential, we\ndetermine the position of the transition from hadronic matter to a quark-gluon\nplasma as a function of $\\mu_I$. We see evidence for a critical endpoint where\nthe transition changes from a crossover to a first-order transition as $\\mu_I$\nis increased. We argue that QCD at finite $\\mu_I$ and QCD at finite\nquark-numberchemical potential $\\mu$ should behave similarly in this region."
    },
    {
        "anchor": "The electroweak Hamiltonian in the gradient flow formalism: Over the last decade the gradient flow formalism has become an important tool\nfor lattice simulations of Quantum Chromodynamics. It offers remarkable\nrenormalization properties which pave the way for cross-fertilization between\nperturbative and lattice calculations. In this contribution we report on the\nconstruction of the flowed operator product expansion for the current-current\noperators of the electroweak Hamiltonian at NNLO QCD. This allows for simpler\ntransformations between lattice and perturbative schemes and might reduce the\nuncertainties of theoretical predictions for low-energy flavor observables.",
        "positive": "Large Nc volume reduction and chiral random matrix theory: Motivated by recent progress on the understanding of the Eguchi-Kawai (EK)\nvolume equivalence and growing interest in conformal window, we simultaneously\nuse the large-Nc volume reduction and Chiral Random Matrix Theory (chRMT) to\nstudy the chiral symmetry breaking of four dimensional SU(Nc) gauge theory with\nadjoint fermions in the large Nc limit. Although some cares are required\nbecause the chRMT limit and 't Hooft limit are not compatible in general, we\nshow that the breakdown of the chiral symmetry can be detected in large-Nc\ngauge theories. As a first step, we mainly focus on the quenched approximation\nto establish the methodology. We first confirm that heavy adjoint fermions,\nintroduced as the center symmetry preserver, work as expected and thanks to\nthem the volume reduction holds. Using massless overlap fermion as a probe, we\nthen calculate the low-lying Dirac spectrum for fermion in the adjoint\nrepresentation to compare to that of chRMT, and find that chiral symmetry is\nindeed broken in the quenched theory."
    },
    {
        "anchor": "Free-form smearing for bottomonium and B meson spectroscopy: To obtain high-quality results from lattice QCD, it is important to use\noperators that produce good signals for the quantities of interest. Free-form\nsmearing is a powerful tool that helps to accomplish that goal. The present\nwork introduces a new implementation of free-form smearing that maintains its\nusefulness and reduces its computational time dramatically. Applications to the\nmass spectrum of $B$, $B_s$, $B_c$ and bottomonium mesons show the\neffectiveness of the method. Results are compared with other lattice QCD\nstudies and with experimental data where available. The present work includes\nthe first lattice QCD exploration for some of these mesons.",
        "positive": "Performance of SSE and AVX Instruction Sets: SSE (streaming SIMD extensions) and AVX (advanced vector extensions) are SIMD\n(single instruction multiple data streams) instruction sets supported by recent\nCPUs manufactured in Intel and AMD. This SIMD programming allows parallel\nprocessing by multiple cores in a single CPU. Basic arithmetic and data\ntransfer operations such as sum, multiplication and square root can be\nprocessed simultaneously. Although popular compilers such as GNU compilers and\nIntel compilers provide automatic SIMD optimization options, one can obtain\nbetter performance by a manual SIMD programming with proper optimization: data\npacking, data reuse and asynchronous data transfer. In particular, linear\nalgebraic operations of vectors and matrices can be easily optimized by the\nSIMD programming. Typical calculations in lattice gauge theory are composed of\nlinear algebraic operations of gauge link matrices and fermion vectors, and so\ncan adopt the manual SIMD programming to improve the performance."
    },
    {
        "anchor": "Non-perturbative Power Corrections to Ghost and Gluon Propagators: We study the dominant non-perturbative power corrections to the ghost and\ngluon propagators in Landau gauge pure Yang-Mills theory using OPE and lattice\nsimulations. The leading order Wilson coefficients are proven to be the same\nfor both propagators. The ratio of the ghost and gluon propagators is thus free\nfrom this dominant power correction. Indeed, a purely perturbative fit of this\nratio gives smaller value ($\\simeq 270$MeV) of $\\Lambda_{\\ms}$ than the one\nobtained from the propagators separately($\\simeq 320$MeV). This argues in\nfavour of significant non-perturbative $\\sim 1/q^2$ power corrections in the\nghost and gluon propagators. We check the self-consistency of the method.",
        "positive": "$\u03c6^4$ lattice model with cubic symmetry in three dimensions: RG-flow\n  and first order phase transitions: We study the $3$-component $\\phi^4$ model on the simple cubic lattice in\npresence of a cubic perturbation. To this end, we perform Monte Carlo\nsimulations in conjunction with a finite size scaling analysis of the data. The\nanalysis of the renormalization group (RG)-flow of a dimensionless quantity\nprovides us with the accurate estimate $Y_4 - \\omega_2 =0.00081(7)$ for the\ndifference of the RG-eigenvalue $Y_4$ at the $O(3)$-symmetric fixed point and\nthe correction exponent $\\omega_2$ at the cubic fixed point. We determine an\neffective exponent $\\nu_{eff}$ of the correlation length that depends on the\nstrength of the breaking of the $O(3)$ symmetry. Field theory predicts that\ndepending on the sign of the cubic perturbation, the RG-flow is attracted by\nthe cubic fixed point, or runs to an ever increasing amplitude, indicating a\nfluctuation induced first order phase transition. We demonstrate directly the\nfirst order nature of the phase transition for a sufficiently strong breaking\nof the $O(3)$ symmetry. We obtain accurate results for the latent heat, the\ncorrelation length in the disordered phase at the transition temperature and\nthe interface tension for interfaces between one of the ordered phases and the\ndisordered phase. We study how these quantities scale with the RG-flow,\nallowing quantitative predictions for weaker breaking of the $O(3)$ symmetry."
    },
    {
        "anchor": "Gauge theories induced by bosons in fundamental representation: A lattice theory of scalar bosons in the fundamental representation of the\ngauge group $SU(N_c)$ and of the global symmetry group $SU(N_f)$ is shown to\ninduce a standard gauge theory only at large $N_f$. The system is in a\ndeconfined phase at strong scalar self-coupling and any finite $N_f$. The\nrequirement of convergence of the effective gauge action imposes a lower limit\non the scalar mass.",
        "positive": "Hadro-quarkonium from Lattice QCD: The hadro-quarkonium picture [S. Dubinskiy and M.B. Voloshin, Phys. Lett. B\n666, 344 (2008)] provides one possible interpretation for the pentaquark\ncandidates with hidden charm, recently reported by the LHCb Collaboration, as\nwell as for some of the charmonium-like \"X,Y,Z\" states. In this picture, a\nheavy quarkonium core resides within a light hadron giving rise to four- or\nfive-quark/antiquark bound states. We test this scenario in the heavy quark\nlimit by investigating the modification of the potential between a static\nquark-antiquark pair induced by the presence of a hadron. Our lattice QCD\nsimulations are performed on a Coordinated Lattice Simulations (CLS) ensemble\nwith $N_f = 2+1$ flavours of non-perturbatively improved Wilson quarks at a\npion mass of about 223 MeV and a lattice spacing of about 0.0854 fm. We study\nthe static potential in the presence of a variety of light mesons as well as of\noctet and decuplet baryons. In all these cases, the resulting configurations\nare favoured energetically. The associated binding energies between the\nquarkonium in the heavy quark limit and the light hadron are found to be\nsmaller than a few MeV, similar in strength to deuterium binding. It needs to\nbe seen if the small attraction survives in the infinite volume limit and\nsupports bound states or resonances."
    },
    {
        "anchor": "Spontaneous Parity Violation: We disprove the Vafa-Witten theorem on the impossibility of spontaneously\nbreaking parity in vector-like gauge field theories, identifying a mechanism\ndriven by quantum fluctuations. With the introduction of a meromorphic Lattice\nformulation, defined over 5 dimensions, we demonstrate that the minima of the\nfree energy can be distinct from the maxima of the partition function :\nidentifying and evaluating a suitable contour for the partition function\ndefined such that asymptotic behaviour of the complex action is\nnon-oscillatory.",
        "positive": "Recent Developments in Fermion Simulation Algorithms: A summary of recent developments in the field of simulation algorithms for\ndynamical fermions is given."
    },
    {
        "anchor": "Large-N string tension from rectangular Wilson loops: In pure SU(N) gauge theory in four dimensions, we determine the string\ntension at large N from smeared rectangular Wilson loops on the lattice. We\nlearn how well loops of sizes barely on the strong-coupling side of the large-N\ntransition in their eigenvalue distribution can be described by effective\nstring theory.",
        "positive": "Semileptonic B to D decays at nonzero recoil with 2+1 flavors of\n  improved staggered quarks. An update: The Fermilab Lattice and MILC collaborations are completing a comprehensive\nprogram of heavy-light physics on MILC (2+1)-flavor asqtad ensembles with\nlattice spacings as small as 0.045 fm and light-to-strange-quark mass ratios as\nlow as 1/20. We use the Fermilab interpretation of the clover action for heavy\nvalence quarks and the asqtad action for the light valence quarks. The central\ngoal of the program is to provide ever more exacting tests of the unitarity of\nthe CKM matrix. We present preliminary results for one part of the program,\nnamely the analysis of the semileptonic decay B -> D l nu at nonzero recoil."
    },
    {
        "anchor": "Eigenmodes of the Dirac Operator and Chiral Properties of QCD with Sea\n  Quarks: I describe a mechanism to understand the relation between chiral-symmetry\nbreaking and eigenmodes of the Dirac operator in lattice QCD with\nKogut-Susskind sea quarks. It can be shown that if chiral symmetry is\nspontaneously broken, the eigenvalues $\\lambda_i$ should behave as $z(i)/V$ for\nlarge volume $V$, where $z(i)$ is the i-th zero of the Bessel function. With\nneither chiral nor $\\lambda$ extrapolation, one can precisely calculate the\nchiral condensate using only a small set of eigenvalues. Therefore, it is\neconomical and free of systematic uncertainties. I present the first QCD data\nto support this mechanism and encourage the lattice community to test and use\nit.",
        "positive": "A Lattice Calculation of the Heavy Quark Universal Form Factor: A preliminary computation of the Isgur-Wise universal form factor using a\nlattice formulation of the Heavy Quark Effective Theory (HQET) is described and\ncompared with the recent data from ARGUS and CLEO on B -> D*lv decay."
    },
    {
        "anchor": "Probing the Region of Massless Quarks in Quenched Lattice QCD using\n  Wilson Fermions: We study the spectrum of $H(m)=\\gamma_5 W(-m)$ with $W(m)$ being the\nWilson-Dirac operator on the lattice with bare mass equal to $m$. The\nbackground gauge fields are generated using the SU(3) Wilson action at\n$\\beta=5.7$ on an $8^3\\times 16$ lattice. We find evidence that the spectrum of\n$H(m)$ is gapless for $1.02 < m < 2.0$, implying that the physical quark is\nmassless in this whole region.",
        "positive": "Spectrum of the Wilson Dirac Operator at Finite Lattice Spacings: We consider the effect of discretization errors on the microscopic spectrum\nof the Wilson Dirac operator using both chiral Perturbation Theory and chiral\nRandom Matrix Theory. A graded chiral Lagrangian is used to evaluate the\nmicroscopic spectral density of the Hermitian Wilson Dirac operator as well as\nthe distribution of the chirality over the real eigenvalues of the Wilson Dirac\noperator. It is shown that a chiral Random Matrix Theory for the Wilson Dirac\noperator reproduces the leading zero-momentum terms of Wilson chiral\nPerturbation Theory. All results are obtained for fixed index of the Wilson\nDirac operator. The low-energy constants of Wilson chiral Perturbation theory\nare shown to be constrained by the Hermiticity properties of the Wilson Dirac\noperator."
    },
    {
        "anchor": "Lattice Scalar Field Theory At Complex Coupling: Lattice scalar field theories encounter a sign problem when the coupling\nconstant is complex. This is a close cousin of the real-time sign problems that\nafflict the lattice Schwinger-Keldysh formalism, and a more distant relative of\nthe fermion sign problem that plagues calculations of QCD at finite density. We\ndemonstrate the methods of complex normalizing flows and contour deformations\non scalar fields in $0+1$ and $1+1$ dimensions, respectively. In both cases,\nintractable sign problems are readily bypassed. These methods extend to\nnegative couplings, where the partition function can be defined only by\nanalytic continuation. Finally, we examine the location of partition function\nzeros, and discuss their relation to the performance of these algorithms.",
        "positive": "Multi-$\u03c0^+$ systems in finite volume: We present a formalism to describe two-$\\pi^+$ and three-$\\pi^+$ dynamics in\nfinite volume, the formalism is based on combination of a variational approach\nand the Faddeev method. Both pair-wise and three-body interactions are included\nin the presentation. Impacts of finite lattice spacing and the cubic lattice\nsymmetry are also discussed. To illustrate application of the formalism, the\npair-wise contact interaction that resembles the leading order interaction\nterms in chiral effective theory is used to analyze recent lattice results."
    },
    {
        "anchor": "Topological Features in a Two-Dimensional Higgs Model: Topological properties of the gauge field in a two-dimensional Higgs model\nare investigated. Results of exploratory numerical simulations are presented.",
        "positive": "Investigating the critical slowing down of QCD simulations: Simulations of QCD are known to suffer from serious critical slowing down\ntowards the continuum limit. This is particularly prominent in the topological\ncharge. We investigate the severeness of the problem in the range of lattice\nspacings used in contemporary simulations and propose a method to give more\nreliable error estimates."
    },
    {
        "anchor": "Disorder parameter for confinement and vacuum field strength correlators: The possibility is explored to relate confinement to properties of gauge\ninvariant field strength correlators.",
        "positive": "Twisted mass QCD at finite temperature: We discuss the use of Wilson fermions with twisted mass for simulations of\nQCD thermodynamics. As a prerequisite for a future analysis of the\nfinite-temperature transition making use of automatic O(a) improvement, we\ninvestigate the phase structure in the space spanned by the hopping parameter\nkappa, the coupling beta, and the twisted mass parameter mu. We present results\nfor N_f=2 degenerate quarks on a 16^3x8 lattice, for which we investigate the\npossibility of an Aoki phase existing at strong coupling and vanishing mu, as\nwell as of a thermal phase transition at moderate gauge couplings and\nnon-vanishing mu."
    },
    {
        "anchor": "About Orientifold Planar Equivalence on the Lattice: The orientifold planar equivalence is the equivalence in the large-N limit of\nthe bosonic sectors of the super Yang-Mills and the QCD with a quark in the\nantisymmetric representation. I give a sketch of the proof of the orientifold\nplanar equivalence in the strong-coupling and large-mass phase on the lattice.\nIt is still matter of discussion, if its validity extends also in the continuum\nlimit.",
        "positive": "Phase transitions and gluodynamics in 2-colour matter at high density: We investigate 2-colour QCD with 2 flavours of Wilson fermion at nonzero\ntemperature T and quark chemical potential mu, with a pion mass of 700 MeV\n(m_pi/m_rho=0.8). From temperature scans at fixed mu we find that the critical\ntemperature for the superfluid to normal transition depends only very weakly on\nmu above the onset chemical potential, while the deconfinement crossover\ntemperature is clearly decreasing with mu. We find indications of a region of\nsuperfluid but deconfined matter at high mu and intermediate T. The static\nquark potential determined from the Wilson loop is found to exhibit a 'string\ntension' that increases at large mu in the 'deconfined' region. The electric\n(longitudinal) gluon propagator in Landau gauge becomes strongly screened with\nincreasing temperature and chemical potential. The magnetic (transverse) gluon\nshows little sensitivity to temperature, and exhibits a mild enhancement at\nintermediate mu before becoming suppressed at large mu."
    },
    {
        "anchor": "G2 gauge theories: QCD can be formulated using any gauge group. One particular interesting\nchoice is to replace SU(3) by the exceptional group G2. Conceptually, this\ngroup is the simplest group with a trivial center. It thus permits to study the\nconjectured relevance of center degrees of freedom for QCD. Practically, since\nall its representation are real, it is possible to perform lattice simulations\nfor this theory also at finite baryon densities. It is thus an excellent\nenvironment to test methods and to investigate general properties of gauge\ntheories at finite densities. We review the status of our understanding of\ngauge theories with the gauge group G2, including Yang-Mills theory,\nYang-Mills-Higgs theory, and QCD both in the vacuum and in the phase diagram.",
        "positive": "Structure Functions on the lattice: We report on a lattice computation of the second moment of the pion matrix\nelement of the twist-2 non-singlet operator corresponding to the average\nmomentum of parton densities. We apply a fully non-perturbatively evaluated\nrunning renormalization constant as well as a careful extrapolation of our\nresults to the continuum limit. Thus the only limitation of our final result is\nthe quenched approximation."
    },
    {
        "anchor": "Double-$\u03b2$ Decay Matrix Elements from Lattice Quantum Chromodynamics: A lattice quantum chromodynamics (LQCD) calculation of the nuclear matrix\nelement relevant to the $nn\\to ppee\\overline{\\nu}_e\\overline{\\nu}_e$ transition\nis described in detail, expanding on the results presented in Ref. [1]. This\nmatrix element, which involves two insertions of the weak axial current, is an\nimportant input for phenomenological determinations of double-$\\beta$ decay\nrates of nuclei. From this exploratory study, performed using unphysical values\nof the quark masses, the long-distance deuteron-pole contribution to the matrix\nelement is separated from shorter-distance hadronic contributions. This\npolarizability, which is only accessible in double-weak processes, cannot be\nconstrained from single-$\\beta$ decay of nuclei, and is found to be smaller\nthan the long-distance contributions in this calculation, but non-negligible.\nIn this work, technical aspects of the LQCD calculations, and of the relevant\nformalism in the pionless effective field theory, are described. Further\ncalculations of the isotensor axial polarizability, in particular near and at\nthe physical values of the light-quark masses, are required for precise\ndeterminations of both two-neutrino and neutrinoless double-$\\beta$ decay rates\nin heavy nuclei.",
        "positive": "Exploiting finite-size-effects to simulate full QCD with light quarks -\n  a progress report: We present a report on the status of the GRAL project (Going Realistic And\nLight), which aims at simulating full QCD with two dynamical Wilson quarks\nbelow the vector meson decay threshold, m_ps/m_v < 0.5, making use of\nfinite-size-scaling techniques."
    },
    {
        "anchor": "Gravitational waves from cosmological first order phase transitions: First order phase transitions in the early Universe generate gravitational\nwaves, which may be observable in future space-based gravitational wave\nobservatiories, e.g. the European eLISA satellite constellation. The\ngravitational waves provide an unprecedented direct view of the Universe at the\ntime of their creation. We study the generation of the gravitational waves\nduring a first order phase transition using large-scale simulations of a model\nconsisting of relativistic fluid and an order parameter field. We observe that\nthe dominant source of gravitational waves is the sound generated by the\ntransition, resulting in considerably stronger radiation than earlier\ncalculations have indicated.",
        "positive": "Universality and Scaling at the chiral transition in two-flavor QCD at\n  finite temperature: The order of the phase transition in finite-temperature QCD with two\ndegenerate light quarks is still an open problem and corresponds to the last\nquestion mark in the zero-density phase diagram of QCD. We argue that\nestablishing the nature of the transition in this case is also a crucial test\nfor numerical simulations of lattice QCD, allowing precise estimates of\npossible systematic errors related e.g. to the choice of fermion-simulation\nalgorithm or of discretized formulation for fermions."
    },
    {
        "anchor": "Application of the path optimization method to the sign problem in an\n  effective model of QCD with a repulsive vector-type interaction: The path optimization method is applied to a QCD effective model with the\nPolyakov loop and the repulsive vector-type interaction at finite temperature\nand density to circumvent the model sign problem. We show how the path\noptimization method can increase the average phase factor and control the model\nsign problem. This is the first study which correctly treats the repulsive\nvector-type interaction in the QCD effective model with the Polyakov-loop via\nthe Markov-chain Monte-Carlo approach. It is shown that the complexification of\nthe temporal component of the gluon field and also the vector-type auxiliary\nfield are necessary to evade the model sign problem within the standard\npath-integral formulation.",
        "positive": "Sparse modeling approach to extract spectral functions with covariance\n  of Euclidean-time correlators of lattice QCD: We present our sparse modeling study to extract spectral functions from\nEuclidean-time correlation functions. In this study covariance between\ndifferent Euclidean times of the correlation function is taken into account,\nwhich was not done in previous studies. In order to check applicability of the\nmethod, we firstly test it with mock data which imitate possible charmonium\nspectral functions. Then, we extract spectral functions from correlation\nfunctions obtained from lattice QCD at finite temperature."
    },
    {
        "anchor": "Pseudoscalar Flavor-Singlet Physics with Staggered Fermions: Accurately calculating the mass of flavor-singlet meson states from numerical\nlattice simulations is an important milestone for lattice QCD. Careful\nmeasurement of the full pseudoscalar flavor-singlet propagator is also a\ncrucial step in understanding the dynamics of the fermion sea on the lattice,\nin particular for potentially non-trivial formulations such as with 2+1-flavor\nstaggered fermions. We briefly describe details of a dynamical QCD calculation\nusing improved staggered fermions, with 30,000 trajectories, that was run for\nour studies of flavour singlet mesons.",
        "positive": "Decays of $1^{-+}$ Charmoniumlike Hybrid: By extracting the transition amplitudes, we give the first lattice QCD\nprediction of the two-body decay partial widths of the $1^{-+}$ charmoniumlike\nhybrid $\\eta_{c1}$. Given the calculated mass value $m_{\\eta_{c1}}=4.329(36)$\nGeV, the $\\eta_{c1}$ decay is dominated by the open charm modes $D_1\\bar{D}$,\n$D^*\\bar{D}$ and $D^*\\bar{D}^*$ with partial widths of $258(133)$ MeV, $88(18)$\nMeV and $150(118)$ MeV, respectively. The coupling of $\\eta_{c1}$ to\n$\\chi_{c1}$ plus a flavor singlet pseudoscalar is not small, but\n$\\chi_{c1}\\eta$ decay is suppressed by the small $\\eta-\\eta'$ mixing angle. The\npartial width of $\\eta_{c1}\\to \\eta_c\\eta'$ is estimated to be around 1 MeV. We\nsuggest experiments to search for $\\eta_{c1}$ in the $P$-wave $D^*\\bar{D}$ and\n$D^*\\bar{D}^*$ systems. Especially, the polarization of $D^*\\bar{D}^*$ can be\nused to distinguish the $1^{-+}$ product (total spin $S=1$) from $1^{--}$\nproducts ($S=0$)."
    },
    {
        "anchor": "New critical phenomena in 2d quantum gravity: We study $q=10$ and $q=200$ state Potts models on dynamical triangulated\nlattices and demonstrate that these models exhibit continuous phase\ntransitions, contrary to the first order transition present on regular\nlattices. For $q=10$ the transition seems to be of 2nd order, while it seems to\nbe of 3rd order for $q=200$. For $q=200$ the phase transition also induces a\ntransition between typical fractal structures of the piecewise linear surfaces\ncorresponding to the triangulations. The typical surface changes from having a\ntree-like structure to a fractal structure characterizing pure gravity when the\ntemperature drops below the critical temperature. An investigation of the\nalignment of spin clusters shows that they are strongly correlated to the\nunderlying fractal structure of the triangulated surfaces.",
        "positive": "Vortes solutions in nonabelian Higgs theories: A new class of vortex solutions is found in SU(2) gauge theories with two\nadjoint representation Higgs bosons. Implications of these new solutions and\ntheir possible connection with Center Gauge fixed pure gauge theories are\ndiscussed."
    },
    {
        "anchor": "Nucleon mass and sigma term from lattice QCD with two light fermion\n  flavors: We analyze Nf=2 nucleon mass data with respect to their dependence on the\npion mass down to mpi = 157 MeV and compare it with predictions from covariant\nbaryon chiral perturbation theory (BChPT). A novel feature of our approach is\nthat we fit the nucleon mass data simultaneously with the directly obtained\npion-nucleon sigma-term. Our lattice data below mpi = 435 MeV is well described\nby O(p^4) BChPT and we find sigma=37(8)(6) MeV for the sigma-term at the\nphysical point. Using the nucleon mass to set the scale we obtain a Sommer\nparameter of r_0=0.501(10)(11) fm.",
        "positive": "Lattice Computation of a Magnetic Monopole Mass: A single magnetic monopole in pure SU(2) gauge theory is simulated on the\nlattice and its mass is computed in the full quantum theory. The results are\nrelevant for our proposed realization of the dual superconductor hypothesis of\nconfinement."
    },
    {
        "anchor": "Lattice Gauge Theory -- Present Status: Lattice gauge theory is our primary tool for the study of non-perturbative\nphenomena in hadronic physics. In addition to giving quantitative information\non confinement, the approach is yielding first principles calculations of\nhadronic spectra and matrix elements. After years of confusion, there has been\nsignificant recent progress in understanding issues of chiral symmetry on the\nlattice. (Talk presented at HADRON 93, Como, Italy, June 1993.)",
        "positive": "Fractal dimension of the topological charge density distribution in\n  SU(2) lattice gluodynamics: We study the effect of cooling on the spatial distribution of the topological\ncharge density in quenched SU(2) lattice gauge theory with overlap fermions. We\nshow that as the gauge field configurations are cooled, the Hausdorff dimension\nof regions where the topological charge is localized gradually changes from d =\n2..3 towards the total space dimension. Therefore, the cooling procedure\ndestroys some of the essential properties of the topological charge\ndistribution."
    },
    {
        "anchor": "Short distance current correlators: Comparing lattice simulations to the\n  instanton liquid: Point to point correlators of currents are computed in quenched QCD using a\nchiral lattice fermion action, the overlap action. I compare correlators made\nof exact quark propagators with correlators restricted to low (less than 500\nMeV) eigenvalue eigenmodes of the Dirac operator. In many cases they show\nqualitative resemblence (typically at small values of the quark mass and\ndistances larger than 0.4 fm) and they differ qualitatively at larger quark\nmasses or at very short distance. Lattice results are in qualitative agreement\n(and in the difference of vector and axial vector channels, quantitative\nagreement) with the expectations of instanton liquid models. The scalar channel\nshows the effects of a quenched finite volume zero mode artifact, a negative\ncorrelator.",
        "positive": "Machine learning Hadron Spectral Functions in Lattice QCD: Hadron spectral functions carry all the information of hadrons and are\nencoded in the Euclidean two-point correlation functions. The extraction of\nhadron spectral functions from the correlator is a typical ill-posed inverse\nproblem and infinite number of solutions to this problem exists. We propose a\nnovel neural network (sVAE) based on the Variation Auto-Encoder (VAE) and\nBayesian theorem. Inspired by the maximum entropy method (MEM) we construct the\nloss function of the neural work such that it includes a Shannon-Jaynes entropy\nterm and a likelihood term. The sVAE is then trained to provide the most\nprobable spectral functions. For the training samples of spectral function we\nused general spectral functions produced from the Gaussian Mixture Model. After\nthe training is done we performed the mock data tests with input spectral\nfunctions consisting 1) only a free continuum, 2) only a resonance peak, 3) a\nresonance peak plus a free continuum and 4) a NRQCD motivated spectral\nfunction. From the mock data test we find that the sVAE in most cases is\ncomparable to the maximum entropy method in the quality of reconstructing\nspectral functions and even outperforms the MEM in the case where the spectral\nfunction has sharp peaks with insufficient number of data points in the\ncorrelator. By applying to temporal correlation functions of charmonium in the\npseudoscalar channel obtained in the quenched lattice QCD at 0.75 $T_c$ on\n$128^3\\times96$ lattices and $1.5$ $T_c$ on $128^3\\times48$ lattices, we find\nthat the resonance peak of $\\eta_c$ extracted from both the sVAE and MEM has a\nsubstantial dependence on the number of points in the temporal direction\n($N_\\tau$) adopted in the lattice simulation and $N_\\tau$ larger than 48 is\nneeded to resolve the fate of $\\eta_c$ at 1.5 $T_c$."
    },
    {
        "anchor": "Determination of the CP restoration temperature at $\u03b8=\u03c0$ in 4D\n  SU(2) Yang-Mills theory through simulations at imaginary $\u03b8$: The 't Hooft anomaly matching condition provides constraints on the phase\nstructure at $\\theta=\\pi$ in 4D SU($N$) Yang-Mills theory. In particular,\nassuming that the theory is confined and the CP symmetry is spontaneously\nbroken at low temperature, it cannot be restored below the deconfining\ntemperature at $\\theta=\\pi$. Here we investigate the CP restoration at\n$\\theta=\\pi$ in the 4D SU(2) case and provide numerical evidence that the CP\nrestoration occurs at a temperature higher than the deconfining temperature\nunlike the known results in the large-$N$ limit, where the CP restoration\noccurs precisely at the deconfining temperature. The severe sign problem at\n$\\theta=\\pi$ is avoided by focusing on the tail of the topological charge\ndistribution at $\\theta=0$, which can be probed by performing simulations at\nimaginary $\\theta$. By analytic continuation with respect to $\\theta$, we\nobtain the topological charge at real $\\theta$.",
        "positive": "Accessing high-momentum nucleons with dilute stochastic sources: A novel stochastic technique combining a dilute source grid of $\\mathbb{Z}_3$\nnoise with iterative momentum-smearing is used to study the proton correlation\nfunction at rest and in boosted frames on two lattice volumes. The technique\nmakes use of the baryonic version of the so-called one-end trick, and the\ndecomposition into signal and noise terms of the resulting stochastic proton\ncorrelation function is made explicit. The number and location of the source\npoints in the dilute grid should be chosen so that the benefits of averaging\nover many locations overcomes the additional statistical error introduced by\nthe noise terms in the desired fitting region. At all nontrivial momentum\nvalues considered we find that the choice of $N=4$--$8$ maximally separated\nsource locations is shown to be optimal, providing a reduced statistical error\nwhen compared with a single point source. This enables us to successfully fit\nthe proton energy at momentum values as high as $|\\vec{p}| \\simeq 3.75$ GeV and\n$|\\vec{p}| \\simeq 2.82$ GeV on the small and large volume respectively."
    },
    {
        "anchor": "Non-perturbative Renormalization Constants using Ward Identities: We extend the application of vector and axial Ward identities to calculate\n$b_A$, $b_P$ and $b_T$, coefficients that give the mass dependence of the\nrenormalization constants of the corresponding bilinear operators in the\nquenched theory. The extension relies on using operators with non-degenerate\nquark masses. It allows a complete determination of the $O(a)$ improvement\ncoefficients for bilinears in the quenched approximation using Ward Identities\nalone. Only the scale dependent normalization constants $Z_P^0$ (or $Z_S^0$)\nand $Z_T$ are undetermined. We present results of a pilot numerical study using\nhadronic correlators.",
        "positive": "Lattice Holography on a Quantum Computer: We explore the potential application of quantum computers to the examination\nof lattice holography, which extends to the strongly-coupled bulk theory\nregime. With adiabatic evolution, we compute the ground state of a spin system\non a $(2+1)$-dimensional hyperbolic lattice, and measure the spin-spin\ncorrelation function on the boundary. Notably, we observe that with achievable\nresources for coming quantum devices, the correlation function demonstrates an\napproximate scale-invariant behavior, aligning with the pivotal theoretical\npredictions of the anti-de Sitter/conformal field theory correspondence."
    },
    {
        "anchor": "Operator Product Expansion on the Lattice: a Numerical Test in the\n  Two-Dimensional Non-Linear Sigma-Model: We consider the short-distance behaviour of the product of the Noether O(N)\ncurrents in the lattice nonlinear sigma-model. We compare the numerical results\nwith the predictions of the operator product expansion, using one-loop\nperturbative renormalization-group improved Wilson coefficients. We find that,\neven on quite small lattices (m a \\approx 1/6), the perturbative operator\nproduct expansion describes that data with an error of 5-10% in a large window\n2a \\ltapprox x \\ltapprox m^{-1}. We present a detailed discussion of the\npossible systematic errors.",
        "positive": "One-thimble regularisation of lattice field theories: is it only a\n  dream?: Lefschetz thimbles regularisation of (lattice) field theories was put forward\nas a possible solution to the sign problem. Despite elegant and conceptually\nsimple, it has many subtleties, a major one boiling down to a plain question:\nhow many thimbles should we take into account? In the original formulation, a\nsingle thimble dominance hypothesis was put forward: in the thermodynamic\nlimit, universality arguments could support a scenario in which the dominant\nthimble (associated to the global minimum of the action) captures the physical\ncontent of the field theory. We know by now many counterexamples and we have\nbeen pursuing multi-thimble simulations ourselves. Still, a single thimble\nregularisation would be the real breakthrough. We report on ongoing work aiming\nat a single thimble formulation of lattice field theories, in particular\nputting forward the proposal of performing Taylor expansions on the dominant\nthimble."
    },
    {
        "anchor": "Investigations of decuplet baryons from meson-baryon interactions in the\n  HAL QCD method: We study decuplet baryons from meson-baryon interactions, in particular,\n$\\Delta$ and $\\Omega$ baryons from P-wave $I=3/2$ $N\\pi$ and $I=0$ $\\Xi\\bar{K}$\ninteractions, respectively. The interaction potentials are calculated in the\nHAL QCD method using 3-quark-type source operators at $m_{\\pi} \\approx\n410~\\textrm{MeV}$. We use the conventional stochastic estimation of all-to-all\npropagators combined with the all-mode averaging to reduce statistical\nfluctuations. We have found that two potentials have quite similar behaviors,\nsuggesting that a mass difference between $\\Delta$ and $\\Omega$ comes mainly\nfrom a difference of kinematical structure between $N\\pi$ and $\\Xi \\bar K$,\nrather than their interactions. The scattering phase shifts calculated from the\npotentials indicate that $\\Delta$ and $\\Omega$ baryons exist as bound states in\nthis lattice setup, whose binding energies are consistent with those obtained\nfrom 2-point functions.",
        "positive": "Anisotropic Goldstone bosons of strong-coupling lattice QCD at high\n  density: We calculate the spectrum of excitations in strong-coupling lattice QCD in a\nbackground of fixed baryon density, at a substantial fraction of the saturation\ndensity. We employ a next-nearest-neighbor fermion formulation that possesses\nthe SU(N_f)xSU(N_f) chiral symmetry of the continuum theory. We find two types\nof massless excitations: type I Goldstone bosons with linear dispersion\nrelations and type II Goldstone bosons with quadratic dispersion relations.\nSome of the type I bosons originate as type II bosons of the nearest-neighbor\ntheory. Bosons of either type can develop anisotropic dispersion relations,\ndepending on the value of N_f and the baryon density."
    },
    {
        "anchor": "On-shell Delta I = 3/2 kaon weak matrix elements with non-zero total\n  momentum: We present our results for the on-shell Delta I = 3/2 kaon decay matrix\nelements using domain wall fermions and the DBW2 gauge action at one coarse\nlattice spacing corresponding to 1/a = 1.31 GeV in the quenched approximation.\nThe on-shell matrix elements are evaluated in two different frames: the\ncenter-of-mass frame and non-zero total-momentum frame. We employ the formula\nproposed by Lellouch and L\\\"uscher in the center-of-mass frame, and its\nextension for non-zero total momentum frame to extract the infinite volume,\non-shell, center-of-mass frame decay amplitudes. We determine the decay\namplitude at the physical pion mass and momentum from the chiral extrapolation\nand an interpolation of the relative momentum using the results calculated in\nthe two frames. We have obtained Re(A_2) = 1.66(23)(^{+48}_{-03})(^{+53}_{-0})\nx 10^{-8} GeV and Im(A_2) = -1.181(26)(^{+141}_{-014})(^{+44}_{-0}) x 10^{-12}\nGeV at the physical point, using the data at the relatively large pion mass,\nm_pi > 0.35 GeV. The first error is statistic, and the second and third are\nsystematic. The second error is estimated with several fits of the chiral\nextrapolation including (quenched) chiral perturbation formula at next to\nleading order using only lighter pion masses. The third one is estimated with\nan analysis using the lattice dispersion relation. The result of Re(A_2) is\nreasonably consistent with experiment.",
        "positive": "Domain Wall Charm Physics with Physical Pion Masses: Decay constants,\n  bag and $\u03be$ parameters: We provide an overview of RBC/UKQCD's charm project on 2+1 flavour physical\npion mass ensembles using M\\\"obius Domain Wall Fermions for the light as well\nas for the charm quark. We discuss the analysis strategy in detail and present\nresults at the different stages of the analysis for $D$ and $D_s$ decay\nconstants as well as the bag and $\\xi$ parameters. We also discuss future\napproaches to extend the reach in the heavy quark mass."
    },
    {
        "anchor": "On the Path Integral Loop Representation of (2+1) Lattice Non-Abelian\n  Theory: A gauge invariant Hamiltonian representation for SU(2) in terms of a spin\nnetwork basis is introduced. The vectors of the spin network basis are\nindependent and the electric part of the Hamiltonian is diagonal in this\nrepresentation. The corresponding path integral for SU(2) lattice gauge theory\nis expressed as a sum over colored surfaces, i.e. only involving the $j_p$\nattached to the lattice plaquettes. This surfaces may be interpreted as the\nworld sheets of the spin networks In 2+1 dimensions, this can be accomplished\nby working in a lattice dual to a tetrahedral lattice constructed on a face\ncentered cubic Bravais lattice. On such a lattice, the integral of gauge\nvariables over boundaries or singular lines -- which now always bound three\ncoloured surfaces -- only contributes when four singular lines intersect at one\nvertex and can be explicitly computed producing a 6-j or Racah symbol. We\nperformed a strong coupling expansion for the free energy. The convergence of\nthe series expansions is quite different from the series expansions which were\nperformed in ordinary cubic lattices. In the case of ordinary cubic lattices\nthe strong coupling expansions up to the considered truncation number of\nplaquettes have the great majority of their coefficients positive, while in our\ncase we have almost equal number of contributions with both signs. Finally, it\nis discused the connection in the naive coupling limit between this action and\nthat of the B-F topological field theory and also with the pure gravity action.",
        "positive": "Various Abelian Projections of $SU(2)$ Lattice Gluodynamics and\n  Aharonov-Bohm Effect in the Field Theory: We show that in general abelian projection of lattice gluodynamics it is not\nonly monopoles but also strings are present. Both these topological excitations\nmay be responsible for the confinement of color. We illustrate our ideas by\nsome explicit results in the Abelian Higgs model with the Villain action."
    },
    {
        "anchor": "Unquenching effects on the coefficients of the L\u00fcscher-Weisz action: The effects of unquenching on the perturbative improvement coefficients in\nthe Symanzik action are computed within the framework of L\\\"uscher-Weisz\non-shell improvement. We find that the effects of quark loops are surprisingly\nlarge, and their omission may well explain the scaling violations observed in\nsome unquenched studies.",
        "positive": "Nucleon structure functions from lattice operator product expansion: Deep-inelastic scattering, in the laboratory and on the lattice, is most\ninstructive for understanding how the nucleon is built from quarks and gluons.\nThe long-term goal is to compute the associated structure functions from first\nprinciples. So far this has been limited to model calculations. In this Letter\nwe propose a new method to compute the structure functions directly from the\nvirtual, all-encompassing Compton amplitude, utilizing the operator product\nexpansion. This overcomes issues of renormalization and operator mixing, which\nso far have hindered lattice calculations of power corrections and higher\nmoments."
    },
    {
        "anchor": "Noise Methods for Flavor Singlet Quantities: A discussion of methods for reducing the noise variance of flavor singlet\nquantities (\"disconnected diagrams\") in lattice QCD is given. After an\nintroduction, the possible advantage of partitioning the Wilson fermion matrix\ninto disjoint spaces is discussed and a numerical comparison of the variance\nfor three possible partitioning schemes is carried out. The measurement\nefficiency of lattice operators is examined and shown to be strongly influenced\nby the Dirac and color partitioning choices. Next, the numerical effects of an\nautomated subtraction algorithm on the noise variance of various disconnected\nloop matrix elements are examined. It is found that there is a dramatic\nreduction in the variance of the Wilson point-split electromagnetic currents\nand that this reduction persists at small quark mass.",
        "positive": "$K_{l3}$ form factors at the physical point on (10.9 fm)$^3$ volume: We present the calculation of the $K_{l3}$ form factors with $N_f = 2 + 1$\nnonperturbatively $O(a)$-improved Wilson quark action and Iwasaki gauge action\nat the physical point on a large volume of (10.9 fm)$^3$ at one lattice spacing\nof $a = 0.085$ fm. We extract the form factors from 3-point functions with\nthree different time separations between the source and sink operators to\nconfirm suppression of excited state contributions. The form factors are\ncalculated in very close to the zero momentum transfer, $q^2 = 0$, thanks to\nthe large volume, so that stable interpolations to $q^2 = 0$ are carried out.\nUsing our form factors, we obtain the form factor at $q^2 = 0$, $f_+(0) =\n0.9603(16)(^{+14}_{\\ -4})(44)(19)(1)$, where the first, second, and fifth\nerrors are statistical, systematic errors from fit functions and the isospin\nbreaking effect, respectively. The third and fourth errors denote the finite\nlattice spacing effects estimated from the renormalization factor and\ncontribution beyond the leading order SU(3) chiral perturbation theory (ChPT).\nThe result of $f_+(0)$ yields the Cabibbo-Kobayashi-Maskawa (CKM) matrix\nelement, $|V_{us}| = 0.2255(13)(4)$, where the first error comes from our\ncalculation and the second from the experiment. This value is consistent with\nthe ones determined from the unitarity of the CKM matrix and the $K_{l2}$ decay\nwithin one standard deviation, while it is slightly larger than recent lattice\ncalculations by at most 1.5 $\\sigma$. Furthermore, we evaluate the shape of the\nform factors and the phase space integral from our results. We confirm that\nthose results are consistent with the experiment, and also $|V_{us}|$\ndetermined with our phase space integral agrees with the one in the above."
    },
    {
        "anchor": "Electromagnetic finite-size effects to the hadronic vacuum polarisation: In order to reach (sub-)per cent level precision in lattice calculations of\nthe hadronic vacuum polarisation, isospin breaking corrections must be\nincluded. This requires introducing QED on the lattice, and the associated\nfinite-size effects are potentially large due to the absence of a mass gap.\nThis means that the finite-size effects scale as an inverse polynomial in $L$\nrather than being exponentially suppressed. Considering the\n$\\mathcal{O}(\\alpha)$ corrected hadronic vacuum polarisation in\nQED$_{\\mathrm{L}}$ with scalar QED as an effective theory, we show that the\nfirst possible term, which is of order $1/L^{2}$, vanishes identically so that\nthe finite-size effects start at order $1/L^{3}$. This cancellation is\nunderstood from the neutrality of the currents involved, and we show that this\ncancellation is universal by also including form factors for the pions. We find\ngood numerical agreement with lattice perturbation theory calculations, as well\nas, up to exponentially suppressed terms, scalar QED lattice simulations.",
        "positive": "Lattice QCD calculation of strong isospin breaking effects: We present a new method to evaluate with high precision the isospin breaking\neffects due to the mass difference between the up and down quarks using lattice\nQCD. Our proposal is applicable in principle to any hadronic observable which\ncan be computed on the lattice. It is based on the expansion of the\npath-integral in powers of the small parameter $m_d - m_u$. In this talk we\ndiscuss how to apply this method to compute the leading isospin breaking\neffects for several physical quantities of interest: the kaon masses, the kaon\ndecay constants and the neutron-proton mass splitting."
    },
    {
        "anchor": "Level Crossing for Hot Sphalerons: We study the spectrum of the Dirac Hamiltonian in the presence of high\ntemperature sphaleron-like fluctuations of the electroweak gauge and Higgs\nfields, relevant for the conditions prevailing in the early universe. The\nfluctuations are created by numerical lattice simulations. It is shown that a\nchange in Chern-Simons number by one unit is accompanied by eigenvalues\ncrossing zero and a change of sign of the generalized chirality $\\tGf=\n(-1)^{2T+1} \\gf$ which labels these modes. This provides further evidence that\nthe sphaleron-like configurations observed in lattice simulations may be viewed\nas representing continuum configurations.",
        "positive": "Chiral magnetic effect in 2+1 flavor QCD+QED: The exciting possibility of direct observation of QCD instantons in heavy-ion\ncollisions has recently been proposed by Kharzeev. The underlying phenomenon,\nknown as the chiral magnetic effect, may have been observed recently at RHIC,\nand a first principles calculation is needed to confirm and understand the\nresults. The chiral magnetic effect is thought to be visible in the symmetric\nphase, at temperatures above the QCD critical temperature, and in the presence\nof an external magnetic field. We report on first 2+1 flavor, domain wall\nfermion, QCD+QED dynamical simulations above the critical temperature, in a\nfixed topological sector(s), which are used to study the electric charge\nseparation produced by the effect."
    },
    {
        "anchor": "Review on novel methods for lattice gauge theories: Formulating gauge theories on a lattice offers a genuinely non-perturbative\nway of studying quantum field theories, and has led to impressive achievements.\nIn particular, it significantly deepened our understanding of quantum\nchromodynamics. Yet, some very relevant problems remain inherently challenging,\nsuch as real time evolution, or the presence of a chemical potential, cases in\nwhich Monte Carlo simulations are hindered by a sign problem.\n  In the last few years, a number of possible alternatives have been put\nforward, based on quantum information ideas, which could potentially open the\naccess to areas of research that have so far eluded more standard methods. They\ninclude tensor network calculations, quantum simulations with different\nphysical platforms and quantum computations, and constitute nowadays a vibrant\nresearch area. Experts from different fields, including experimental and\ntheoretical high energy physics, condensed matter, and quantum information, are\nturning their attention to these interdisciplinary possibilities, and driving\nthe progress of the field. The aim of this article is to review the status and\nperspectives of these new avenues for the exploration of lattice gauge\ntheories.",
        "positive": "The Gluon Moment and Parton Distribution Function of the Pion from $N_f\n  = 2 + 1 + 1$ Lattice QCD: We present the first calculation of the pion gluon moment from lattice QCD in\nthe continuum-physical limit. The calculation is done using clover fermions for\nthe valence action with three pion masses, 220, 310 and 690 MeV, and three\nlattice spacings, 0.09, 0.12, and 0.15 fm, using ensembles generated by MILC\nCollaboration with 2+1+1 flavors of highly improved staggered quarks (HISQ). On\nthe lattice, we nonperturbatively renormalize the gluon operator in RI/MOM\nscheme using the cluster-decomposition error reduction (CDER) technique to\nenhance the signal-to-noise ratio of the renormalization constant. We\nextrapolate the pion gluon moment to the continuum-physical limit and obtain\n$0.364(38)_{\\text{stat}+\\text{NPR}}(36)_\\text{mixing}$ in the\n$\\overline{\\text{MS}}$ scheme at 2 GeV, with first error being the statistical\nerror and uncertainties in nonperturbative renormalization, and the second\nbeing a systematic uncertainty estimating the effect of ignoring quark mixing.\nOur pion gluon momentum fraction has a central value lower than two recent\nsingle-ensemble lattice-QCD results near physical pion mass but is consistent\nwith the recent global fits by JAM and xFitter and with most QCD-model\nestimates."
    },
    {
        "anchor": "Beautiful Baryons from Lattice QCD: We perform a lattice study of heavy baryons, containing one ($\\Lambda_b$) or\ntwo $b$-quarks ($\\Xi_b$). Using the quenched approximation we obtain for the\nmass of $\\Lambda_b$ $$ M_{\\Lambda_b}= 5.728 \\pm 0.144 \\pm 0.018 {\\rm GeV}.$$\nThe mass splitting between the $\\Lambda_b$ and the B-meson is found to increase\nby about 20\\% if the light quark mass is varied from the chiral limit to the\nstrange quark mass.",
        "positive": "Lattice B-Physics: I review the status of lattice simulations relevant for phenomenological\nstudies of B-physics. Results for much-studied quantities such as f_B, B_B and\nform-factors for semileptonic decays are presented as well as those for\nquantities which have begun to be studied only recently (such as B-lifetimes).\nThe improvement in the precision of the determinations of the mass of the\nb-quark, which has been made possible by new results for perturbative\ncoefficients, is discussed. Finally I describe new ideas being developed with\nthe aim of making computations of two-body non-leptonic decays possible."
    },
    {
        "anchor": "A machine learning approach to the classification of phase transitions\n  in many flavor QCD: Normalizing flows are generative machine learning models which can\nefficiently approximate probability distributions, using only given samples of\na distribution. This architecture is used to interpolate the chiral condensate\nobtained from QCD simulations with five degenerate quark flavors in the HISQ\naction. From this a model for the probability distribution of the chiral\ncondensate as function of lattice volume, quark mass and gauge coupling is\nobtained. Using the model, first order and crossover regions can be classified\nand the boundary between these regions can be marked by a critical mass. An\nextension of this model to studies of phase transitions in QCD with variable\nnumber of flavors is expected to be possible.",
        "positive": "RG decimation study of SU(2) gauge theory: We report on numerical studies of RG decimations in SU(2) gauge theory. We\nstudy in particular a class of plaquette actions involving sums of group\nrepresentations. We measure a number of observables representative of different\nlength scales in order to investigate the transformation of the system under\ndifferent choices of spin blocking, and examine the flow of the effective\naction couplings. A need for a projection to some class of effective actions on\nthe configurations resulting from the adopted numerical decimation procedures\nis demonstrated. A numerical decimation procedure resulting in the effective\nsingle plaquette Lagrangian tailored to reproduce different medium/large scale\nphysics is devised."
    },
    {
        "anchor": "The Dirac spectrum in Complex Langevin Simulations of QCD: We show that the spectrum of the Dirac operator in complex Langevin\nsimulations of QCD at non-zero chemical potential must behave in a way which is\nradically different from the one in simulations with ordinary non-complexified\ngauge fields: At low temperatures the small eigenvalues of the Dirac operator\nmust be inside the quark mass for chemical potentials as large as a third of\nthe nucleon mass. In particular, in the chiral limit the Dirac eigenvalues of\ncomplex Langevin simulations must accumulate at the origin.",
        "positive": "Variational Study of the Phase Transition at Finite T in the $\u03bb\n  \u03c6^4 $-Theory: Assuming triviality of the 4-dimensional $\\lambda \\phi ^4$-theory we compute\nthe effective potential by means of a self consistent Feynman-Bogoliubov\nmethod. This potential $U_{eff}^{FB}$ depends on a UV-cutoff, which is fixed by\na stability condition for the gap-equation for the plasma mass. It shows a\nsecond order phase transition at zero temperature, in agreement with a large\namount of analytical and RG analysis as well as Monte Carlo numerical evidence.\nAs the cutoff $\\Lambda $ is removed the renormalized self coupling constant\n$\\lambda _R$ goes to zero consistent with the claim of triviality. At finite\ntemperature the phase transition becomes weakly first order."
    },
    {
        "anchor": "The Wiener-Hermite expansions of the Langevin transitions: New partial differential equations for the Wiener-Hermite expansions of the\nLangevin (stochastic) transitions are formulated. They are solved recursively\nin full order series solutions with respect to $\\sqrt{t}$. A sort of 'gauge'\ndegrees of freedom (arbitrariness) involved in the solutions are analyzed and\nclarified. The Wiener-Hermite expansions play important roles as basic elements\nof numerical simulations of the Langevin equations. Specific solutions within\nsome orders are presented as examples. These expansions giving integral\nrepresentations of the Fokker-Planck evolution kernels, similar formulations\nare possible for the imaginary time Hamiltonian evolution kernels as well.",
        "positive": "Quark mass dependence of the pseudoscalar hairpin vertex: In a recent investigation of chiral behavior in quenched lattice QCD, the\nflavor-singlet pseudoscalar ``hairpin'' vertex associated with the eta prime\nmass was studied for pion masses ranging from approximately 275 to 675 MeV.\nThroughout this mass range, the quark-disconnected pseudoscalar correlator is\nwell-described by a pure double-pion-pole diagram with a p^2 independent mass\ninsertion. The residue of the double pole was found to exhibit a significant\nquark mass dependence, evidenced by a negative slope of the effective mass\ninsertion (m_0^{eff})^2 as a function of m_{\\pi}^2. It has been observed by\nSharpe that, with a consistent NLO calculation in quenched chiral perturbation\ntheory, this mass dependence is uniquely predicted in terms of the single-pole\ncoefficient \\alpha_{\\Phi} and the Leutwyler parameter L_5. Since \\alpha_{\\Phi}\nis found to be approximately zero, the chiral slope of the double-pole residue\ndetermines a value for L_5. This provides a consistency check between the\nchiral slope of the hairpin mass insertion and that of the pion decay constant.\nWe investigate the consistency of these mass dependences in our Monte Carlo\nresults at two values of lattice spacing. Within statistics, the slopes are\nfound to be consistent with the Q\\chiPT prediction, confirming that the\nobserved negative slope of m_0^{eff} arises as an effect of the L_5 Leutwyler\nterm."
    },
    {
        "anchor": "The effective Coulomb potential in SU(3) lattice Yang-Mills theory: We study the infrared behavior of the effective Coulomb potential in lattice\nSU(3) Yang-Mills theory in the Coulomb gauge. We use lattices up to a size of\n48^4 and three values of the inverse coupling, beta=5.8, 6.0 and 6.2. While\nfinite-volume effects are hardly visible in the effective Coulomb potential,\nscaling violations and a strong dependence on the choice of Gribov copy are\nobserved. We obtain bounds for the Coulomb string tension that are in agreement\nwith Zwanziger's inequality relating the Coulomb string tension to the Wilson\nstring tension.",
        "positive": "Colour field densities of the quark-antiquark excited flux tubes in\n  SU(3) lattice QCD: We combine techniques previously utilised to study flux tube field density\nprofiles and to study the excited spectrum of the gluonic fields produced by a\nstatic quark-antiquark pair. Working with pure gauge SU(3) fields discretised\nin a lattice, we utilise Wilson loops with a large basis of gluonic spacelike\nWilson lines to include different excitations of the quark-antiquark flux tube.\nTo increase the signal over noise ratio, we use the multihit technique in the\ntemporal Wilson lines and the APE smearing in spatial Wilson lines. The number\nof gluonic operators combined with the space points where we compute the flux\ntube densities turns out to be very large, and we resort to GPUs and to CUDA\ncodes. Computing the effective mass plot from the diagonalized correlation\nmatrix, we separate the excitations with different two-dimensional angular\nmomentum, parity and radial quantum numbers. We then compute the colour field\ndensity profiles for all the components of the colour electric and colour\nmagnetic fields. We analyse our results for the first excitations of the flux\ntube and search for signals of novel phenomena beyond the Nambu-Goto string\nmodel, such as a longitudinal mode or an explicit gluon."
    },
    {
        "anchor": "Excited B mesons from the lattice: We determine the energies of the excited states of a heavy-light meson\n$Q\\bar{q}$, with a static heavy quark and light quark with mass approximately\nthat of the strange quark from both quenched lattices and with dynamical\nfermions. We are able to explore the energies of orbital excitations up to L=3,\nthe spin-orbit splitting up to L=2 and the first radial excitation. These $b\n\\bar{s}$ mesons will be very narrow if their mass is less than 5775 MeV -- the\n$BK$ threshold. We investigate this in detail and present evidence that the\nscalar meson (L=1) will be very narrow and that as many as 6 $b \\bar{s}$\nexcited states will have energies close to the $BK$ threshold and should also\nbe relatively narrow.",
        "positive": "Lattice approach to high-energy hadron-hadron scattering: We discuss the non perturbative approach to the problem of high-energy\nhadron-hadron (dipole-dipole) scattering at low momentum transfer by means of\nnumerical simulations in Lattice Gauge Theory."
    },
    {
        "anchor": "String Breaking as a Mixing Phenomenon in the SU(2) Higgs Model: We study the potential of a static quark anti-quark pair in the confinement\n``phase'' of the SU(2) Higgs model. Around separation r_b, the confining string\nof the gauge field breaks by formation of a dynamical pair of light quarks. The\nground state and first excited state static potentials are determined by a\nvariational technique from a matrix correlation in which suitably smeared gauge\nand Higgs fields enter. Our results at beta=2.4 clearly show string breaking\n(r_b ~ 1.9r_0). The investigation of properly defined overlaps confirms the\ninterpretation of string breaking as a level crossing phenomenon between\nstring-type and meson-type states. We study the scaling properties of the\nstatic potentials along a line of constant physics, varying the lattice spacing\nby a factor of 2. Our results show compatibility with scaling within tiny\nerrors.",
        "positive": "Lattice QCD with a chirally twisted mass term: Lattice QCD with Wilson quarks and a chirally twisted mass term represents a\npromising alternative regularization of QCD, which does not suffer from\nunphysical fermion zero modes. We show how the correlation functions of the\nrenormalized theory are related to the theory with a standard parameterization\nof the mass term. In particular we discuss the conditions under which these\nrelations take the same form as obtained from naive continuum considerations.\nWe discuss in detail some applications and comment on potential benefits and\nproblems of this framework."
    },
    {
        "anchor": "Charmed and $\u03c6$ meson decay constants from 2+1-flavor lattice QCD: On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical\npion mass, we calculate the decay constants of $D_{s}^{(*)}$, $D^{(*)}$ and\n$\\phi$. The lattice size is $48^3\\times96$, which corresponds to a spatial\nextension of $\\sim5.5$ fm with the lattice spacing $a\\approx 0.114$ fm. For the\nvalence light, strange and charm quarks, we use overlap fermions at several\nmass points close to their physical values. Our results at the physical point\nare $f_D=213(5)$ MeV, $f_{D_s}=249(7)$ MeV, $f_{D^*}=234(6)$ MeV,\n$f_{D_s^*}=274(7)$ MeV, and $f_\\phi=241(9)$ MeV. The couplings of $D^*$ and\n$D_s^*$ to the tensor current ($f_V^T$) can be derived, respectively, from the\nratios $f_{D^*}^T/f_{D^*}=0.91(4)$ and $f_{D_s^*}^T/f_{D_s^*}=0.92(4)$, which\nare the first lattice QCD results. We also obtain the ratios\n$f_{D^*}/f_D=1.10(3)$ and $f_{D_s^*}/f_{D_s}=1.10(4)$, which reflect the size\nof heavy quark symmetry breaking in charmed mesons. The ratios\n$f_{D_s}/f_{D}=1.16(3)$ and $f_{D_s^*}/f_{D^*}=1.17(3)$ can be taken as a\nmeasure of SU(3) flavor symmetry breaking.",
        "positive": "Finite-volume energy spectrum of the $K^-K^-K^-$ system: The dynamics of multi-kaon systems are of relevance for several areas of\nnuclear physics. However, even the simplest systems, two and three kaons, are\nhard to prepare and study experimentally. Here we show how to extract this\ninformation using first-principle lattice QCD results. We (1) extend the\nrelativistic three-body quantization condition to the strangeness sector,\npredicting for the first time the excited level finite-volume spectrum of three\nkaon systems at maximal isospin, and (2) present a first lattice QCD\ncalculation of the excited levels of this system in a finite box. We compare\nour predictions with the lattice results reported here and with previous ground\nstate calculations and find very good agreement."
    },
    {
        "anchor": "Masses of mesons with charm valence quarks from 2+1+1 flavor twisted\n  mass lattice QCD: We present preliminary results of an ongoing lattice QCD computation of the\nspectrum of $D$ mesons and $D_s$ mesons and of charmonium using 2+1+1 flavors\nof twisted mass sea and valence quarks.",
        "positive": "Hadron Spectroscopy with lattice QCD: challenges and opportunities: Ongoing challenges in computing the spectrum of hadronic resonances and\nshallow bound-states from lattice QCD are reviewed. Since such states are\nidentified as poles in the scattering matrix, nearby non-analyticities must be\ntreated to analytically continue to complex center-of-mass energies.\nSignificant lattice spacing effects have also been observed in some channels,\nnecessitating a continuum limit. Recent achievements are also highlighted,\nincluding lattice investigations of states in the charm region, baryon-baryon\nscattering, and the first coupled channel meson-baryon amplitude in the\n$\\Lambda(1405)$ channel."
    },
    {
        "anchor": "The Spatial String Tension in High Temperature Lattice Gauge Theories: We develop some techniques which allow an analytic evaluation of space-like\nobservables in high temperature lattice gauge theories. We show that such\nvariables are described extremely well by dimensional reduction. In particular,\nby using results obtained in the context of ``Induced QCD'', we evaluate the\ncontributions to space-like observables coming from the Higgs sector of the\ndimensionally reduced action, we find that they are of higher order in the\ncoupling constant compared to those coming from the space-like action and hence\nneglegible near the continuum limit. In the case of SU(2) gauge theory our\nresults agree with those obtained through Montecarlo simulations both in (2+1)\nand (3+1) dimensions and they also indicate a possible way of removing the gap\nbetween the two values of $g^2(T)$ recently appeared in the literature.",
        "positive": "Mesons at high temperature in Nf=2 QCD: We report first results for spectral functions of charmonium in 2-flavour\nQCD. The spectral functions are determined from vector and pseudoscalar\ncorrelators on a dynamical, anisotropic lattice. J/psi and eta_c are found to\nsurvive well into the deconfined phase before melting away at T<~2T_c. Current\nsystematic uncertainties prevent us from drawing any definite conclusions at\nthis stage."
    },
    {
        "anchor": "Scaling behavior and sea quark dependence of pion spectrum with\n  HYP-smeared staggered fermions: We study the pion spectrum (and in particular taste-symmetry breaking within\nit) using HYP-smeared valence staggered fermions on the coarse and fine MILC\nlattices (which have asqtad staggered sea quarks). We focus on the dependence\non lattice spacing and sea-quark mass. We also update our results on source\ndependence. Our main conclusion is that on the MILC fine lattices the\nappropriate power-counting for SU(3) staggered chiral perturbation theory may\nhave discretization errors entering at next-to-leading order rather than at\nleading-order.",
        "positive": "Fluctuations and correlations in high temperature QCD: We calculate second- and fourth-order cumulants of conserved charges in a\ntemperature range stretching from the QCD transition region towards the realm\nof (resummed) perturbation theory. We perform lattice simulations with\nstaggered quarks; the continuum extrapolation is based on $N_t=10\\dots24$ in\nthe crossover-region and $N_t=8\\dots16$ at higher temperatures. We find that\nthe Hadron Resonance Gas model predictions describe the lattice data rather\nwell in the confined phase. At high temperatures (above $\\sim$250 MeV) we find\nagreement with the three-loop Hard Thermal Loop results."
    },
    {
        "anchor": "A numerical attempt on the Chiral Schwinger Model: The chiral Schwinger model is formulated in the wilson-fermion formulation on\nthe lattice and then simulated by the complex langevin algorithm. The\nsimulation is done both without and with gauge fixing to the Lorentz gauge for\nthe compact gauge links. Some preliminary results are presented which indicate\nthat the complex langevin is well behaving with the complex chiral fermion\ndeterminant.",
        "positive": "Composite boson dominance in relativistic field theories: We apply a new bosonization technique to relativistic field theories of\nfermions whose partition function is dominated by bosonic composites, and\nderive the effective action for these bosons. The derivation respects all\nsymmetries, including gauge invariance, with the exception of Euclidean\ninvariance which must be checked a posteriori. We use a lattice regularization\nwhich should make applications to gauge theories easier. We test the method on\na fermion field theory with quartic interaction in the limit when the number of\nflavours N_f is large, and show that it reproduces the exact results in the\nbosonic sector, namely condensation of a compositeboson with the right mass\nwhich breaks the discrete chiral invariance of the model. Moreover we determine\nthe structure function of the condensed composite, whose spatial part turns out\nto be identical to that of the Cooper pairs of the BCS model of\nsuperconductivity."
    },
    {
        "anchor": "Evidence for the Role of Instantons in Hadron Structure from Lattice QCD: Cooling is used as a filter on a set of gluon fields sampling the Wilson\naction to selectively remove essentially all fluctuations of the gluon field\nexcept for the instantons. The close agreement between quenched lattice QCD\nresults with cooled and uncooled configurations for vacuum correlation\nfunctions of hadronic currents and for density-density correlation functions in\nhadronic bound states provides strong evidence for the dominant role of\ninstantons in determining light hadron structure and quark propagation in the\nQCD vacuum.",
        "positive": "Finite-Size Scaling in the $O(N)$ $\u03c6^4_4$ Model: Perturbation theory and renormalization group methods are used to derive a\nfinite-size scaling theory for the partition function zeroes and thermodynamic\nfunctions in the $O(n)$ $\\phi^4$ model in four dimensions. The leading\npower--law scaling behaviour is the same as that of the mean field theory.\nThere exist, however, multiplicative logarithmic corrections which are linked\nto the triviality of the theory."
    },
    {
        "anchor": "Clover Action for Blue Gene-Q and Iterative solvers for DWF: In Lattice QCD, a major challenge in simulating physical quarks is the\ncomputational complexity of these simulations. In this proceeding, we describe\nthe optimisation of Clover fermion action for Blue gene-Q architecture and how\ndifferent iterative solvers behave for Domain Wall Fermion action. We find that\nthe optimised Clover term achieved a maximum efficiency of 29.1% and 20.2% for\nsingle and double precision respectively for iterative Conjugate Gradient\nsolver. For Domain Wall Fermion action (DWF) we found that Modified Conjugate\nResidual(MCR) as the most efficient solver compared to CG and GCR. We have\ndeveloped a new multi-shift MCR algorithm that is 18.5% faster compared to\nmulti-shift CG for the evaluation of rational functions in RHMC.",
        "positive": "Color superconductivity in a small box: a complex Langevin study: It is expected that the color superconductivity (CSC) phase appears in QCD at\nlow temperature and high density. On the basis of the lattice perturbation\ntheory, a possible parameter region in which the CSC occurs has been predicted.\nIn this work, we perform complex Langevin simulation on an $8^3\\times 128$\nlattice using four-flavor staggered fermions. We find, in particular, that the\nquark number has plateaux with respect to the chemical potential similar to our\nprevious study, indicating the formation of the Fermi sphere. A\ndiquark-antidiquark operator, which is an order parameter of color\nsuperconductivity, is formulated on the lattice using the U(1) noise. Our\nresult for this operator is found to fluctuate violently when the Fermi surface\ncoincides with the energy levels of quarks. We also discuss partial restoration\nof the chiral symmetry at high density."
    },
    {
        "anchor": "Universal scaling properties of QCD close to the chiral limit: We present a lattice QCD based determination of the chiral phase transition\ntemperature in QCD with two massless (up and down) and one strange quark having\nits physical mass. We propose and calculate two novel estimators for the chiral\ntransition temperature for several values of the light quark masses,\ncorresponding to Goldstone pion masses in the range of $58~{\\rm MeV}\\lesssim\nm_\\pi\\lesssim 163~{\\rm MeV}$. The chiral phase transition temperature is\ndetermined by extrapolating to vanishing pion mass using universal scaling\nrelations. After thermodynamic, continuum and chiral extrapolations we find the\nchiral phase transition temperature $T_c^0=132^{+3}_{-6}$ MeV. We also show\nsome preliminary calculations that use the conventional estimator for the\npseudo-critical temperature and compare with the new estimators for $T_c^0$.\nFurthermore, we show results for the ratio of the chiral order parameter and\nits susceptibility and argue that this ratio can be used to differentiate\nbetween $O(N)$ and $Z_2$ universality classes in a non-parametric manner.",
        "positive": "A lattice formulation of Weyl fermions on a single curved surface: In the standard lattice domain-wall fermion formulation, one needs two flat\ndomain-walls where both of the left- and right-handed massless modes appear. In\nthis work we investigate a single domain-wall system with a nontrivial curved\nbackground. Specifically we consider a massive fermion on a three-dimensional\nsquare lattice, whose domain-wall is a two-dimensional sphere. In the free\ntheory, we find that a single Weyl fermion is localized at the wall and it\nfeels gravity through the induced spin connection. With a topologically\nnontrivial $U(1)$ link gauge field, however, we find a zero mode with the\nopposite chirality localized at the center where the gauge field is singular.\nIn the latter case, the low-energy effective theory is not chiral but\nvectorlike. We discuss how to circumvent this obstacle in formulating lattice\nchiral gauge theory in the single domain-wall fermion system."
    },
    {
        "anchor": "Perturbative versus non-perturbative decoupling of heavy quarks: We simulate a theory with $N_f=2$ heavy quarks of mass $M$. At energies much\nsmaller than $M$ the heavy quarks decouple and the theory can be described by\nan effective theory which is a pure gauge theory to leading order in $1/M$. We\npresent results for the mass dependence of ratios such as $t_0(M)/t_0(0)$. We\ncompute these ratios from simulations and compare them to the perturbative\nprediction. The latter relies on a factorisation formula for the ratios which\nis valid to leading order in $1/M$.",
        "positive": "Three dimensional lattice gravity as supersymmetric Yang-Mills theory: We argue that a certain twisted supersymmetric Yang-Mills theory in three\ndimensions with gauge group SU(2) possesses a set of topological observables\nwhose expectation values can be computed in a related Chern Simons theory. This\nChern Simons theory has been proposed as a definition of three dimensional\nEuclidean quantum gravity. Since the YM theory admits a discretization which\npreserves the values of topological observables we conjecture that it can be\nused as a non-perturbative definition of the quantum gravity theory."
    },
    {
        "anchor": "Extrapolations of Lattice Meson Form Factors: We use chiral perturbation theory to study the extrapolations necessary to\nmake physical predictions from lattice QCD data for the electromagnetic form\nfactors of pseudoscalar mesons. We focus on the quark mass, momentum, lattice\nspacing, and volume dependence and apply our results to simulations employing\nmixed actions of Ginsparg-Wilson valence quarks and staggered sea quarks. To\ndetermine charge radii at quark masses on the lattices currently used, we find\nthat all extrapolations except the one to infinite volume make significant\ncontributions to the systematic error.",
        "positive": "SU(N) chiral gauge theories on the lattice: We extend the construction of lattice chiral gauge theories based on\nnon-perturbative gauge fixing to the non-abelian case. A key ingredient is that\nfermion doublers can be avoided at a novel type of critical point which is only\naccessible through gauge fixing, as we have shown before in the abelian case.\nThe new ingredient allowing us to deal with the non-abelian case as well is the\nuse of equivariant gauge fixing, which handles Gribov copies correctly, and\navoids Neuberger's no-go theorem. We use this method in order to gauge fix the\nnon-abelian group (which we will take to be SU(N)) down to its maximal abelian\nsubgroup. Obtaining an undoubled, chiral fermion content requires us to\ngauge-fix also the remaining abelian gauge symmetry. This modifies the\nequivariant BRST identities, but their use in proving unitarity remains intact,\nas we show in perturbation theory. On the lattice, equivariant BRST symmetry as\nwell as the abelian gauge invariance are broken, and a judiciously chosen\nirrelevant term must be added to the lattice gauge-fixing action in order to\nhave access to the desired critical point in the phase diagram. We argue that\ngauge invariance is restored in the continuum limit by adjusting a finite\nnumber of counter terms. We emphasize that weak-coupling perturbation theory\napplies at the critical point which defines the continuum limit of our lattice\nchiral gauge theory."
    },
    {
        "anchor": "Two-Dimensional Lattice Gravity as a Spin System: Quantum gravity is studied in the path integral formulation applying the\nRegge calculus. Restricting the quadratic link lengths of the originally\ntriangular lattice the path integral can be transformed to the partition\nfunction of a spin system with higher couplings on a Kagome lattice. Various\nmeasures acting as external field are considered. Extensions to matter fields\nand higher dimensions are discussed.",
        "positive": "Light nuclei and nucleon form factors in $N_f=2+1$ lattice QCD: We present our result of binding energy of light nuclei with the nuclear mass\nnumber less than or equal to four at the pion mass $m_\\pi = 0.3$ GeV. The\nsimulations are performed in $N_f=2+1$ QCD with Iwasaki gauge and a\nnon-perturbative improved Wilson quark actions at the lattice spacing of $a =\n0.09$ fm. We discuss the $m_\\pi$ dependence of the binding energies by\ncomparing with previous results. Furthermore, we show preliminary results for\nthe axial charge and the Dirac radius obtained from the nucleon form factors at\nalmost physical $m_\\pi$."
    },
    {
        "anchor": "Phase structure of the CP(1) model in the presence of a topological\n  $\u03b8$-term: We numerically study the phase structure of the CP(1) model in the presence\nof a topological $\\theta$-term, a regime afflicted by the sign problem for\nconventional lattice Monte Carlo simulations. Using a bond-weighted tensor\nrenormalization group method, we compute the free energy for inverse couplings\nranging from $0\\leq \\beta \\leq 1.1$ and find a CP-violating, first-order phase\ntransition at $\\theta=\\pi$. In contrast to previous findings, our numerical\nresults provide no evidence for a critical coupling $\\beta_c<1.1$ above which a\nsecond-order phase transition emerges at $\\theta=\\pi$ and/or the first-order\ntransition line bifurcates at $\\theta\\neq\\pi$. If such a critical coupling\nexists, as suggested by Haldane's conjecture, our study indicates that is\nlarger than $\\beta_c>1.1$.",
        "positive": "Systematic approximation for QCD at non-zero density: We use the heavy dense formulation of QCD (HD-QCD) as the basis for an\nanalytic expansion as systematic approximation to QCD at non-zero density,\nkeeping the full Yang-Mills action. We analyse the structure of the baryonic\ndensity and other quantities and present data from the complex Langevin\nequation (CLE) and reweighting (RW) calculations for 2 flavours of Wilson\nfermions."
    },
    {
        "anchor": "Meson masses in external magnetic fields with HISQ fermions: We studied the temporal correlation function of mesons in the pseudo-scalar\nchannel in (2+1)-flavor QCD in the presence of external magnetic fields at zero\ntemperature. The simulations were performed on $32^3 \\times 96$ lattices using\nthe Highly Improved Staggered Quarks (HISQ) action with $m_{\\pi} \\approx $ 230\nMeV. The strength of magnetic fields $|eB|$ ranges from 0 to around 3.3 GeV$^2$\n($\\sim 60 m_\\pi^2$). We found that the masses of neutral pseudo-scalar\nparticles, e.g. neutral pion and kaon, monotonouslly decrease as the magnetic\nfield grows and then saturate at a nonzero value. It is observed that heavier\nneutral pseudo-scalars are less affected by magnetic fields. Moreover, we found\na non-monotonous behavior of charged pion and kaon mass in magnetic field for\nthe first time. In the case of small magnetic field (0 $\\leq~|eB| \\lesssim$ 0.3\nGeV$^2~\\sim 6m_\\pi^2$ ) the mass of charged pseudo-scalar grows with magnetic\nfield and can be well described by the Lowest Landau Level approximation, while\nfor $|eB|$ larger than 0.3 GeV$^2$ the mass starts to decrease. The possible\nconnection between $|eB|$ dependences of neutral pion mass and the decreasing\nbehavior of pseudo-critical temperature in magnetic field is discussed. Due to\nthe nonzero value of neutral pion mass our simulation indicates that the\nsuperconducting phase of QCD does not exist in the current window of magnetic\nfield.",
        "positive": "Bayesian study of relativistic open and hidden charm in anisotropic\n  lattice QCD: We present the first combined study of correlators and spectral properties of\ncharmonium and open-charm-mesons at finite temperature using a fully\nrelativistic lattice QCD approach. The QCD medium is captured by second\ngeneration anisotropic 24^3xN_t lattices from the FASTSUM collaboration,\nincluding 2+1 flavors of clover discretized quarks with m_pi~380 MeV. Two\nBayesian methods are deployed to reconstruct the spectral functions, the recent\nBR method as well as the Maximum Entropy Method with Fourier basis. We take\nparticular care to disentangle genuine in-medium effects from method artifacts\nwith the help of the reconstructed correlator. Consistent with the direct\ninspection of correlators, we observe no significant in-medium modification for\nJ/Psi and eta_c around the crossover, while the chi_c states on the other hand\nshow clear changes around the transition. At the highest temperature, T=352\nMeV, J/Psi and eta_c also exhibit discernible changes compared to the vacuum.\nFor D mesons around $T_c$, no significant modifications are observed, but we\nfind clear indications that no bound state survives at the highest temperature\nof T=352 MeV. Above T_c we discover a significant difference between D and D*\nmesons, the latter being much more strongly affected by the medium."
    },
    {
        "anchor": "On the question of universality in $\\RPn$ and $\\On$ Lattice Sigma Models: We argue that there is no essential violation of universality in the\ncontinuum limit of mixed $\\RPn$ and $\\On$ lattice sigma models in 2 dimensions,\ncontrary to opposite claims in the literature.",
        "positive": "Computing the lowest eigenvalues of the Fermion matrix by subspace\n  iterations: Subspace iterations are used to minimise a generalised Ritz functional of a\nlarge, sparse Hermitean matrix. In this way, the lowest $m$ eigenvalues are\ndetermined. Tests with $1 \\leq m \\leq 32$ demonstrate that the computational\ncost (no. of matrix multiplies) does not increase substantially with $m$. This\nimplies that, as compared to the case of a $m=1$, the additional eigenvalues\nare obtained for free."
    },
    {
        "anchor": "Non-perturbative renormalisation for overlap fermions: Using non-perturbative techniques we have found the renormalisation factor,\nZ, in the RI-MOM scheme for quark bilinear operators in quenched QCD. We worked\nwith overlap fermions using the Luescher-Weisz gauge action. Our calculation\nwas performed at beta=8.45 at a lattice spacing of 1/a=2.1 GeV using a value of\nrho=1.4. Our results show good agreement between the vector and the axial\nvector in the zero mass limit. This shows that overlap fermions have good\nchiral properties. To attempt to improve the discretisation errors in our\nresults we subtracted the O(a^2) terms in one-loop lattice perturbation theory\nfrom the Monte Carlo Green functions. In particular we paid attention to the\noperators for the observable <x>. We found a value for the renormalisation\nconstants Z^msbar_(v_2b) and Z^msbar_(v_2a) just less than 1.9 at mu=1/a=2.1\nGeV.",
        "positive": "Bs and Bc mesons in lattice QCD with exact chiral symmetry: We determine the masses and decay constants of the pseudoscalar mesons Bs and\nBc, and also the masses of the vector mesons Bs^* and Bc^*, in quenched lattice\nQCD with exact chiral symmetry. For 100 gauge configurations generated with\nsingle-plaquette action at beta = 7.2 on the 32^3 x 60 lattice, we compute\npoint-to-point quark propagators for 33 quark masses in the range [0.01, 0.85],\nand measure the time-correlation functions of pseudoscalar and vector mesons.\nThe inverse lattice spacing and the charm quark bare mass are determined using\nthe mass and decay constant of eta_c(2980). The bare masses of s and b quarks\nare chosen such that the masses of the corresponding vector mesons are in good\nagreement with phi(1020), and Upsilon(9460) respectively. Our results are:\nm_{Bs} = 5385(27)(17) MeV, f_{Bs} = 253(8)(7) MeV, m_{Bc} = 6278(6)(4) MeV,\nf_{Bc} = 489(4)(3) MeV, m_{Bs^*} = 5424(28)(19) MeV, and m_{Bc^*} = 6315(6)(5)\nMeV."
    },
    {
        "anchor": "Adaptive stepsize and instabilities in complex Langevin dynamics: Stochastic quantization offers the opportunity to simulate field theories\nwith a complex action. In some theories unstable trajectories are prevalent\nwhen a constant stepsize is employed. We construct algorithms for generating an\nadaptive stepsize in complex Langevin simulations and find that unstable\ntrajectories are completely eliminated. To illustrate the generality of the\napproach, we apply it to the three-dimensional XY model at nonzero chemical\npotential and the heavy dense limit of QCD.",
        "positive": "Hadronic form factors for rare semileptonic $B$ decays: We discuss first results for the computation of short distance contributions\nto semileptonic form factors for the rare $B$ decays $B \\to K^{*} \\ell^+\\ell^-$\nand $B_s \\to \\phi \\ell^+ \\ell^-$. Our simulations are based on RBC/UKQCD's\n$N_f=2+1$ ensembles with domain wall light quarks and the Iwasaki gauge action.\nFor the valence $b$-quark we chose the relativistic heavy quark action."
    },
    {
        "anchor": "The gradient flow coupling from numerical stochastic perturbation theory: Perturbative calculations of gradient flow observables are technically\nchallenging. Current results are limited to a few quantities and, in general,\nto low perturbative orders. Numerical stochastic perturbation theory is a\npotentially powerful tool that may be applied in this context. Precise results\nusing these techniques, however, require control over both statistical and\nsystematic uncertainties. In this contribution, we discuss some recent\nalgorithmic developments that lead to a substantial reduction of the cost of\nthe computations. The matching of the ${\\overline{\\rm MS}}$ coupling with the\ngradient flow coupling in a finite box with Schr\\\"odinger functional boundary\nconditions is considered for illustration.",
        "positive": "Neural network approach to reconstructing spectral functions and complex\n  poles of confined particles: Reconstructing spectral functions from propagator data is difficult as\nsolving the analytic continuation problem or applying an inverse integral\ntransformation are ill-conditioned problems. Recent work has proposed using\nneural networks to solve this problem and has shown promising results, either\nmatching or improving upon the performance of other methods. We generalize this\napproach by not only reconstructing spectral functions, but also (possible)\npairs of complex poles or an infrared (IR) cutoff. We train our network on\nphysically motivated toy functions, examine the reconstruction accuracy and\ncheck its robustness to noise. Encouraging results are found on both toy\nfunctions and genuine lattice QCD data for the gluon propagator, suggesting\nthat this approach may lead to significant improvements over current\nstate-of-the-art methods."
    },
    {
        "anchor": "Axial $U_A(1)$ Anomaly: a New Mechanism to Generate Massless Bosons: Prior to the establishment of $QCD$ as the correct theory describing hadronic\nphysics, it was realized that the essential ingredients of the hadronic world\nat low energies are chiral symmetry and its spontaneous breaking. Spontaneous\nsymmetry breaking is a non-perturbative phenomenon and thanks to massive $QCD$\nsimulations on the lattice we have at present a good understanding on the\nvacuum realization of the non-abelian chiral symmetry as a function of the\nphysical temperature. As far as the $U_A(1)$ anomaly is concerned, and\nespecially in the high temperature phase, the current situation is however far\nfrom satisfactory. The first part of this article is devoted to review the\npresent status of lattice calculations, in the high temperature phase of $QCD$,\nof quantities directly related to the $U_A(1)$ axial anomaly. In the second\npart I will analyze some interesting physical implications of the $U_A(1)$\nanomaly, recently suggested, in systems where the non-abelian axial symmetry is\nfulfilled in the vacuum. More precisely I will argue that, if the $U_A(1)$\nsymmetry remains effectively broken, the topological properties of the theory\ncan be the basis of a mechanism, other than Goldstone's theorem, to generate a\nrich spectrum of massless bosons at the chiral limit.",
        "positive": "Including heavy spin effects in the prediction of a $\\bar{b} \\bar{b} u\n  d$ tetraquark with lattice QCD potentials: We investigate spin effects in four-quark systems consisting of two heavy\nanti-bottom quarks and two light up/down quarks. To this end we use the\nBorn-Oppenheimer approximation. We utilize potentials of two static antiquarks\nin the presence of two quarks of finite mass computed via lattice QCD and solve\na coupled-channel Schr\\\"odinger equation for the anti-bottom-anti-bottom\nseparation. Without taking heavy quark spins into account this approach\npredicted a $u d \\bar b \\bar b$ tetraquark bound state with quantum numbers\n$I(J^P) = 0(1^+)$. We now extend this Born-Oppenheimer approach with coupled\nchannel Schr\\\"odinger equations allowing us to incorporate effects due to the\nheavy $\\bar b$ spins. We confirm the existence of the $u d \\bar b \\bar b$\ntetraquark."
    },
    {
        "anchor": "Correlations of Energy-Momentum Tensor via Gradient Flow in SU(3)\n  Yang-Mills Theory at Finite Temperature: Euclidean two-point correlators of the energy-momentum tensor (EMT) in SU(3)\ngauge theory on the lattice are studied on the basis of the Yang-Mills gradient\nflow. The entropy density and the specific heat obtained from the two-point\ncorrelators are shown to be in good agreement with those from the one-point\nfunctions of EMT. These results constitute a first step toward the first\nprinciple simulations of the transport coefficients with the gradient flow.",
        "positive": "Dynamical QCD+QED simulation with staggered quarks: Electromagnetic effects play an important role in many phenomena such as\nisospin-symmetry breaking in the hadron spectrum and the hadronic contributions\nto g-2. We have generalized the MILC QCD code to include the electromagnetic\nfield. In this work, we focus on simulations including charged sea quarks using\nthe RHMC algorithm. We show details of the dynamical QCD+QED simulation\nalgorithm with compact QED. We analyze the code performance and results for\nhadron-spectrum observables."
    },
    {
        "anchor": "The glueball spectrum from novel improved actions: Results for the inter-quark potential and low-lying SU(3) glueball spectrum\nfrom simulations using a new improved action are presented. The action,\nsuitable for highly anisotropic lattices, contains a two-plaquette term\ncoupling with a negative coefficient as well as incorporating Symanzik\nimprovement.",
        "positive": "N$_f$ = 1 QCD in External Magnetic Fields: Staggered Fermions: We investigate N$_f$ = 1 QCD in external magnetic fields on the lattice. The\nbackground field is introduced by means of the so-called Schrodinger\nfunctional. We adopt standard staggered fermions with constant bare mass $am =\n0.025$ and magnetic fields with constant magnetic flux up to $a^2 e H \\simeq\n2.3562$. We find that the the deconfinement and chiral symmetry restoration\ntemperatures do not depend on the strength of the applied magnetic field. Our\nmethod allow us to easily study the effects of the external magnetic fields on\nthe QCD thermodynamics. We determine the influences of applied magnetic fields\nto the free energy, pressure, and equation of state of strongly interacting\nmatter."
    },
    {
        "anchor": "A Lattice QCD study of the $\u03c1$ resonance: We present a lattice QCD study of the $\\rho$ resonance with $N_f=2+1$ clover\nfermions at a pion mass of approximately $320$ MeV and lattice size $3.6$ fm.\nWe consider two processes involving the $\\rho$. The first process is elastic\nscattering of two pions in P-wave with isospin $1$. Using the L\\\"uscher method\nwe determine the scattering phase shift, from which we obtain the $\\rho$\nresonance mass and decay width $\\Gamma(\\rho\\to\\pi\\pi)$. The second process is\nthe radiative transition $\\pi\\gamma\\to\\pi\\pi$, where we follow the\nBrice\\~no-Hansen-Walker-Loud approach to determine the transition amplitude in\nthe invariant mass region near the $\\rho$ resonance and for both space- and\ntime-like photon momentum. This allows us to determine the coupling between the\n$\\rho$, the pion and the photon, and the resulting $\\rho$ radiative decay\nwidth.",
        "positive": "O(N) Models with Topological Lattice Actions: A variety of lattice discretisations of continuum actions has been\nconsidered, usually requiring the correct classical continuum limit. Here we\ndiscuss \"weird\" lattice formulations without that property, namely lattice\nactions that are invariant under most continuous deformations of the field\nconfiguration, in one version even without any coupling constants. It turns out\nthat universality is powerful enough to still provide the correct quantum\ncontinuum limit, despite the absence of a classical limit, or a perturbative\nexpansion. We demonstrate this for a set of O(N) models (or non-linear\n$\\sigma$-models). Amazingly, such \"weird\" lattice actions are not only in the\nright universality class, but some of them even have practical benefits, in\nparticular an excellent scaling behaviour."
    },
    {
        "anchor": "Excited mesons from $N_f=2$ dynamical Clover Wilson lattices: We study mesons on the lattice with a special focus on excited states. For\nthat purpose we construct several quark sources with different spatial\nsmearings, including p-waves. These quark sources are then combined with the\nappropiate Dirac structures to form meson interpolators of definite spin. We\nuse these operators to construct a cross correlation matrix from which we\nextract ground and excited meson states using the variational method. For the\ncalculations we use gauge configurations with $N_f=2$ dynamical Clover Wilson\nfermions provided by the CP-PACS collaboration. We show preliminary results for\npseudoscalar, scalar, vector and pseudovector mesons.",
        "positive": "Complex Langevin Simulations of QCD at Finite Density -- Progress Report: We simulate lattice QCD at finite quark-number chemical potential to study\nnuclear matter, using the complex Langevin equation (CLE). The CLE is used\nbecause the fermion determinant is complex so that standard methods relying on\nimportance sampling fail. Adaptive methods and gauge-cooling are used to\nprevent runaway solutions. Even then, the CLE is not guaranteed to give correct\nresults. We are therefore performing extensive testing to determine under what,\nif any, conditions we can achieve reliable results. Our earlier simulations at\n$\\beta=6/g^2=5.6$, $m=0.025$ on a $12^4$ lattice reproduced the expected phase\nstructure but failed in the details. Our current simulations at $\\beta=5.7$ on\na $16^4$ lattice fail in similar ways while showing some improvement. We are\ntherefore moving to even weaker couplings to see if the CLE might produce the\ncorrect results in the continuum (weak-coupling) limit, or, if it still fails,\nwhether it might reproduce the results of the phase-quenched theory. We also\ndiscuss action (and other dynamics) modifications which might improve the\nperformance of the CLE."
    },
    {
        "anchor": "Finite Size Analysis of the One-dimensional $q = \\infty$ Clock Model: We analyze the finite size scaling of the $q$-state clock model in the $q\n\\rightarrow \\infty$ limit. The behaviors of the specific heat, Binder-Landau\nand U4 cumulants agree with the Borgs-Koteck\\'y ans\\\"atz for first order phase\ntransitions. However, we find that the leading correction to the position of\nthe extremal points of these quantities is not universal. On the other hand,\nthe finite size corrections to the mass gap behave like for second order phase\ntransitions. In particular, the curves corresponding to different size\napproximations do not cross in the vicinity of the transition points. The\nfeature is associated to the existence of a divergent correlation length and\nholds for a wider class of models.",
        "positive": "Kaon oscillations in the Standard Model and Beyond using Nf=2 dynamical\n  quarks: We compute non-perturbatively the B-parameters of the complete basis of\nfour-fermion operators needed to study the Kaon oscillations in the SM and in\nits supersymmetric extension. We perform numerical simulations with two\ndynamical maximally twisted sea quarks at three values of the lattice spacing\non configurations generated by the ETMC. Unwanted operator mixings and O(a)\ndiscretization effects are removed by discretizing the valence quarks with a\nsuitable Osterwalder-Seiler variant of the Twisted Mass action. Operators are\nrenormalized non-perturbatively in the RI/MOM scheme. Our preliminary result\nfor BK(RGI) is 0.73(3)(3)."
    },
    {
        "anchor": "Equation of state and more from lattice regularized QCD: We present results from a calculation of the QCD equation of state with two\nlight (up, down) and one heavier (strange) quark mass performed on lattices\nwith three different values of the lattice cut-off. We show that also on the\nfinest lattice analyzed by us observables sensitive to deconfinement and chiral\nsymmetry restoration, respectively, vary most rapidly in the same temperature\nregime.",
        "positive": "f_B and f_Bs with maximally twisted Wilson fermions: We present a lattice QCD calculation of the heavy-light decay constants f_B\nand f_Bs performed with Nf=2 maximally twisted Wilson fermions, at four values\nof the lattice spacing. The decay constants have been also computed in the\nstatic limit and the results are used to interpolate the observables between\nthe charm and the infinite-mass sectors, thus obtaining the value of the decay\nconstants at the physical b quark mass. Our preliminary results are f_B=191(14)\nMeV, f_Bs=243(14) MeV, f_Bs/f_B=1.27(5). They are in good agreement with those\nobtained with a novel approach, recently proposed by our Collaboration (ETMC),\nbased on the use of suitable ratios having an exactly known static limit."
    },
    {
        "anchor": "Lattice QCD noise reduction for bosonic correlators through blocking: We propose a method to substantially improve the signal-to-noise ratio of\nlattice correlation functions for bosonic operators or other operator\ncombinations with disconnected contributions. The technique is applicable for\ncorrelations between operators on two planes (zero momentum correlators) when\nthe dimension of the plane is larger than the separation between the two planes\nwhich are correlated. In this case, the correlation arises primarily from\npoints whose in-plane coordinates are close, but noise arises from all pairs of\npoints. By breaking each plane into bins and computing bin-bin correlations, it\nis possible to capture these short-distance correlators exactly while replacing\n(small) correlators at large spatial extent with a fit, with smaller\nuncertainty than the data. The cost is only marginally larger than averaging\neach plane before correlating, but the improvement in signal-to-noise can be\nsubstantial. We test the method on correlators of the gradient-flowed\ntopological charge density and squared field strength, finding noise reductions\nby a factor of $\\sim$ 3$-$7 compared to the conventional approach on the same\nensemble of configurations.",
        "positive": "Simulations of N=1 supersymmetric Yang-Mills theory with three colours: We report on our recent results regarding numerical simulations of the four\ndimensional, N=1 Supersymmetric Yang-Mills theory with SU(3) gauge symmetry and\nlight dynamical gluinos."
    },
    {
        "anchor": "Higher-Twist Contribution to Pion Structure Function: 4-Fermi Operators: We present quenched lattice QCD results for the contribution of higher-twist\noperators to the lowest non-trivial moment of the pion structure function. To\nbe specific, we consider the combination $F_2^{\\pi^+} + F_2^{\\pi^-} - 2\nF_2^{\\pi^0}$ which has $I = 2$ and receives contributions from 4-Fermi\noperators only. We introduce the basis of lattice operators. The\nrenormalization of the operators is done perturbatively in the $\\bar{\\rm{MS}}$\nscheme using the 't Hooft-Veltman prescription for $\\gamma_5$, taking\nparticular care of mixing effects. The contribution is found to be of\n$O(f_\\pi^2/Q^2)$, relative to the leading contribution to the moment of\n$F_2^{\\pi^+}$.",
        "positive": "Looking at the deconfinement transition using Wilson flow: Wilson flow is an effective tool for constructing renormalized composite\noperators. We explore use of the Wilson flow to construct renormalized order\nparameters for the deconfinement transition in SU(3) gauge theory. We discuss\nrenormalization of the Polyakov loop, and of gluon condensates."
    },
    {
        "anchor": "Cluster simulation of relativistic fermions in two space-time dimensions: For Majorana-Wilson lattice fermions in two dimensions we derive a dimer\nrepresentation. This is equivalent to Gattringer's loop representation, but is\nmade exact here on the torus. A subsequent dual mapping leads to yet another\nrepresentation in which a highly efficient Swendsen-Wang type cluster algorithm\nis constructed. It includes the possibility of fluctuating boundary conditions.\nIt also allows for improved estimators and makes interesting new observables\naccessible to Monte Carlo. The algorithm is compatible with the Gross-Neveu as\nwell as an additional Z(2) gauge interaction. In this article numerical\ndemonstrations are reported for critical free fermions.",
        "positive": "Topological susceptibility in 2+1-flavor QCD with chiral fermions: We compute the topological susceptibility $\\chi_t$ of 2+1-flavor lattice QCD\nwith dynamical M\\\"obius domain-wall fermions, whose residual mass is kept at 1\nMeV or smaller. In our analysis, we focus on the fluctuation of the topological\ncharge density in a \"slab\" sub-volume of the simulated lattice, as proposed by\nBietenholz et al. The quark mass dependence of our results agrees well with the\nprediction of the chiral perturbation theory, from which the chiral condensate\nis extracted. Combining the results for the pion mass $M_\\pi$ and decay\nconstant $F_\\pi$, we obtain $\\chi_t$ = 0.227(02)(11)$M_\\pi^2 F_\\pi^2$ at the\nphysical point, where the first error is statistical and the second is\nsystematic."
    },
    {
        "anchor": "Monopole Chains in the Compact Abelian Higgs Model with doubly-charged\n  Matter Field: We study the properties of topological defects in the lattice compact Abelian\nHiggs Model with charge Q=2 matter field. We find that monopoles and\nantimonopoles form chain-like structures which are dense in the\nconfinement/symmetric phase. In this phase the mentioned structures explain\nboth the confinement of single-charged and the breaking of strings spanned\nbetween doubly-charged test particles. This observation helps to understand how\nthe non-diagonal gluons, once taken into consideration in the Abelian\nprojection of gluodynamics, could reproduce in this framework the string\nbreaking for adjoint charges.",
        "positive": "On QCD strings beyond non-interacting model: We investigate the implications of Nambu-Goto (NG), L\\\"uscher-Weisz (LW) and\nPolyakov-Kleinert (PK) string actions for the Casimir energy of the QCD\nflux-tube at one and two loop order at finite temperature. We perform our\nnumerical study on the 4-dim pure SU(3) Yang-Mills lattice gauge theory at\nfinite temperature $\\beta=6.0$. The static quark-antiquark potential is\ncalculated using link-integrated Polyakov loop correlators. At a high\ntemperature-close to the critical point- We find that the rigidity and\nself-interactions effects of the QCD string to become detectable. The\nremarkable feature of this model is that it retrieves a correct dependency of\nthe renormalized string tension on the temperature. Good fit to static\npotential data at source separations $R \\ge 0.5$ fm is obtained when including\nadditional two-boundary terms of (LW) action. On the other-hand, at a lower\ntemperature-near the QCD plateau- We detect signatures of two boundary terms of\nthe L\\\"uscher-Weisz (LW) string action. The (LW) string with boundary action is\nyielding a static potential which is in a good agreement with the lattice data,\nhowever, for color source separation as short as $R=0.3$ fm."
    },
    {
        "anchor": "Introduction to Normalizing Flows for Lattice Field Theory: This notebook tutorial demonstrates a method for sampling Boltzmann\ndistributions of lattice field theories using a class of machine learning\nmodels known as normalizing flows. The ideas and approaches proposed in\narXiv:1904.12072, arXiv:2002.02428, and arXiv:2003.06413 are reviewed and a\nconcrete implementation of the framework is presented. We apply this framework\nto a lattice scalar field theory and to U(1) gauge theory, explicitly encoding\ngauge symmetries in the flow-based approach to the latter. This presentation is\nintended to be interactive and working with the attached Jupyter notebook is\nrecommended.",
        "positive": "Lattice QCD estimate of the $\u03b7_{c}(2S)\\to J/\u03c8\u03b3$ decay rate: We compute the hadronic matrix element relevant to the physical radiative\ndecay $\\eta_{c}(2S)\\to J/\\psi\\gamma$ by means of lattice QCD. We use the\n(maximally) twisted mass QCD action with Nf=2 light dynamical quarks and from\nthe computations made at four lattice spacings we were able to take the\ncontinuum limit. The value of the mass ratio $m_{\\eta_c(2S)}/m_{\\eta_c(1S)}$ we\nobtain is consistent with the experimental value, and our prediction for the\nform factor is $V^{\\eta_{c}(2S)\\to J/\\psi\\gamma}(0)\\equiv\nV_{12}(0)=0.32(6)(2)$, leading to $\\Gamma(\\eta_c (2S) \\to J/\\psi\\gamma) =\n(15.7\\pm 5.7)$ keV, which is much larger than $\\Gamma(\\psi (2S) \\to\n\\eta_c\\gamma)$ and within reach of modern experiments."
    },
    {
        "anchor": "Finite size scaling of meson propagators with isospin chemical potential: We determine the volume and mass dependence of scalar and pseudoscalar\ntwo-point functions in N_f-flavour QCD, in the presence of an isospin chemical\npotential and at fixed gauge-field topology. We obtain these results at second\norder in the \\epsilon-expansion of Chiral Perturbation Theory and evaluate all\nrelevant zero-mode group integrals analytically. The virtue of working with a\nnon-vanishing chemical potential is that it provides the correlation functions\nwith a dependence on both the chiral condensate, \\Sigma, and the pion decay\nconstant, F, already at leading order. Our results may therefore be useful for\nimproving the determination of these constants from lattice QCD calculations.\nAs a side product, we rectify an earlier calculation of the O(\\epsilon^2)\nfinite-volume correction to the decay constant appearing in the partition\nfunction. We also compute a generalised partition function which is useful for\nevaluating U(N_f) group integrals.",
        "positive": "Technical notes on a 2-d lattice O(N) model problem: This paper provides a technical companion to M. Aguado and E. Seiler,\nhep-lat/0406041, in which the fate of perturbation theory in the thermodynamic\nlimit is discussed for the O(N) model on a 2d lattice and different boundary\nconditions. The techniques used to compute perturbative coefficients are\nexplained, and results for all boundary conditions considered reviewed in\ndetail."
    },
    {
        "anchor": "Universal fluctuations in spectra of the lattice Dirac operator: Recently, Kalkreuter obtained the complete Dirac spectrum for an $SU(2)$\nlattice gauge theory with dynamical staggered fermions on a $12^4$ lattice for\n$\\beta =1.8$ and $\\beta=2.8$. We performed a statistical analysis of his data\nand found that the eigenvalue correlations can be described by the Gaussian\nSymplectic Ensemble. In particular, long range fluctuations are strongly\nsuppressed: the variance of a sequence of levels containing $n$ eigenvalues on\naverage is given by $\\Sigma_2(n) \\sim\\frac 1{2\\pi^2}(\\log n + {\\rm const.})$\ninstead of $\\Sigma_2(n) = n$ for a random sequence of levels. Our findings are\nin agreement with the anti-unitary symmetry of the lattice Dirac operator for\n$N_c=2$ with staggered fermions which differs from the continuuum theory. For\n$N_c = 3$ we predict that the eigenvalue correlations are given by the Gaussian\nUnitary Ensemble.",
        "positive": "2D Quantum Gravity -Three States of Surfaces-: Two-dimensional random surfaces are studied numerically by the dynamical\ntriangulation method. In order to generate various kinds of random surfaces,\ntwo higher derivative terms are added to the action. The phases of surfaces in\nthe two-dimensional parameter space are classified into three states: flat,\ncrumpled surface, and branched polymer. In addition, there exists a special\npoint (pure gravity) corresponding to the universal fractal surface. A new\nprobe to detect branched polymers is proposed, which makes use of the\nminbu(minimum neck baby universe) analysis. This method can clearly distinguish\nthe branched polymer phase from another according to the sizes and arrangements\nof baby universes. The size distribution of baby universes changes drastically\nat the transition point between the branched polymer and other kind of surface.\nThe phases of surfaces coupled with multi-Ising spins are studied in a similar\nmanner."
    },
    {
        "anchor": "Monopole condensation in two-flavour Adjoint QCD: Two distinct phase transitions occur at different temperatures in QCD with\nadjoint fermions (aQCD): deconfinement and chiral symmetry restoration. In this\nmodel, quarks do no explicitely break the center Z(3) symmetry and therefore\nthe Polyakov loop is a good order parameter for the deconfinement transition.\nWe study monopole condensation by inspecting the expectation value of an\noperator which creates a monopole. Such a quantity is expected to be an order\nparameter for the deconfinement transition as in the case of fundamental\nfermions.",
        "positive": "$B\\to D^{(\\ast)}\\ell\u03bd$ at non-zero recoil: $B$ anomalies play a prominent role in Beyond the Standard Model (BSM)\nphysics searches. In particular, the long standing tension between the\ninclusive and the exclusive determinations of the CKM matrix element $|V_{cb}|$\nand the current tensions in the $R(D)$--$R(D^\\ast)$ plane between theory and\nexperiment have brought the $B\\to D^{(\\ast)}\\ell\\nu$ semileptonic processes to\nthe spotlight. Existing lattice-QCD calculations of the $B\\to D\\ell\\nu$ form\nfactors at non-zero recoil are being complemented with very recent developments\nin the $B\\to D^\\ast\\ell\\nu$ channel. In this review I discuss recent progress\nin lattice calculations of $B\\to D^{(\\ast)}\\ell\\nu$, as well as the\nimplications of these results for high precision determinations of $|V_{cb}|$\nand the Lepton Flavor Universality (LFU) ratios $R(D^{(\\ast)})$."
    },
    {
        "anchor": "Phase Transitions in Induced QCD: The variety of the phase transitions in Induced QCD are studied. Depending\nupon the parameters in the scalar field potential, there could be infinite\nnumber of fixed points, with different critical behavior. The integral equation\nfor the density of the eigenvalues of the scalar field are generalized to the\nweak coupling phases, with the gap at the origin. We find a wide class of the\nmassive solutions of these integral equations in the strong coupling phases,\nand derive an explicit eigenvalue equation for the scalar branch of the mass\nspectrum.",
        "positive": "Chiral properties of domain-wall quarks in quenched QCD: We investigate the chiral properties of quenched domain-wall QCD (DWQCD) at\nthe lattice spacings $a^{-1} \\simeq 1$ and 2 GeV for both plaquette and\nrenormalization-group (RG) improved gauge actions. In the case of the plaquette\naction we find that the quark mass defined through the axial Ward-Takahashi\nidentity remains non-vanishing in the DWQCD chiral limit that the bare quark\nmass $m_f\\to 0$ and the length of the fifth dimension $N_s\\to\\infty$,\nindicating that chiral symmetry is not realized with quenched DWQCD up to\n$a^{-1} \\simeq 2$ GeV. The behavior is much improved for the RG-improved gauge\naction: while a non-vanishing quark mass remains in the chiral limit at\n$a^{-1}\\simeq 1$ GeV, the result at $a^{-1}\\simeq 2$ GeV is consistent with an\nexponentially vanishing quark mass in the DWQCD chiral limit, indicating the\nrealization of exact chiral symmetry. An interpretation and implications are\nbriefly discussed."
    },
    {
        "anchor": "Parallel tempering in full QCD with Wilson fermions: We study the performance of QCD simulations with dynamical Wilson fermions by\ncombining the Hybrid Monte Carlo algorithm with parallel tempering on $10^4$\nand $12^4$ lattices. In order to compare tempered with standard simulations,\ncovariance matrices between sub-ensembles have to be formulated and evaluated\nusing the general properties of autocorrelations of the parallel tempering\nalgorithm. We find that rendering the hopping parameter $\\kappa$ dynamical does\nnot lead to an essential improvement. We point out possible reasons for this\nobservation and discuss more suitable ways of applying parallel tempering to\nQCD.",
        "positive": "Connecting phase transitions between the 3-d O(4) Heisenberg model and\n  4-d SU(2) lattice gauge theory: SU(2) lattice gauge theory is extended to a larger coupling space where the\ncoupling parameter for horizontal (spacelike) plaquettes, $\\beta_H$, differs\nfrom that for vertical (Euclidean timelike) plaquettes, $\\beta_V$. When\n$\\beta_H \\rightarrow \\infty$ the system, when in Coulomb Gauge, splits into\nmultiple independent 3-d O(4) Heisenberg models on spacelike hyperlayers.\nThrough consideration of the robustness of the Heisenberg model phase\ntransition to small perturbations, and illustrated by Monte Carlo simulations,\nit is shown that the ferromagnetic phase transition in this model persists for\n$\\beta_H < \\infty$. Once it has entered the phase-plane it must continue to\nanother edge due to its symmetry-breaking nature, and therefore must\nnecessarily cross the $\\beta_V = \\beta_H$ line at a finite value. Indeed, a\nhigher-order SU(2) phase transition is found at $\\beta = 3.18 \\pm 0.08$, from a\nfinite-size scaling analysis of the Coulomb gauge magnetization from Monte\nCarlo simulations, which also yields critical exponents. An important technical\nbreakthrough is the use of open boundary conditions, which is shown to reduce\nsystematic and random errors of the overrelaxation gauge-fixing algorithm by a\nfactor of several hundred. The string tension and specific heat are also shown\nto be consistent with finite-order scaling about this critical point using the\nsame critical exponents."
    },
    {
        "anchor": "Quantitative comparison of filtering methods in lattice QCD: We systematically compare filtering methods used to extract topological\nexcitations (like instantons, calorons, monopoles and vortices) from lattice\ngauge configurations, namely APE-smearing and spectral decompositions based on\nlattice Dirac and Laplace operators. Each of these techniques introduces\nambiguities, which can invalidate the interpretation of the results. We show,\nhowever, that all these methods, when handled with care, reveal very similar\ntopological structures. Hence, these common structures are free of ambiguities\nand faithfully represent infrared degrees of freedom in the QCD vacuum. As an\napplication we discuss an interesting power-law for the clusters of filtered\ntopological charge.",
        "positive": "Translating topological benefits in very cold lattice simulations: Master-field simulations offer an approach to lattice QCD in which\ncalculations are performed on a small number of large-volume gauge-field\nconfigurations. The latter is advantageous for simulations in which the global\ntopological charge is frozen due to a very fine lattice spacing, as the effect\nof this on observables is suppressed by the spacetime volume. Here we make use\nof the recently developed Stabilised Wilson Fermions to investigate a variation\nof this approach in which only the temporal direction ($T$) is taken larger\nthan in traditional calculations. As compared to a hyper-cubic lattice\ngeometry, this has the advantage that finite-$L$ effects can be useful, e.g.\nfor multi-hadron observables, while compared to open boundary conditions,\ntime-translation invariance is not lost.\n  In this proof-of-concept contribution, we study the idea of using very cold\n(i.e. long-$T$) lattices to topologically \"defrost\" observables at fine lattice\nspacing. We identify the scalar-scalar meson two-point correlation function as\na useful probe and present first results from $N_f=3$ ensembles with time\nextents up to $T=2304$ and a lattice spacing of $a=0.055\\,\\rm{fm}$."
    },
    {
        "anchor": "Random Walks in Noninteger Dimension: One can define a random walk on a hypercubic lattice in a space of integer\ndimension $D$. For such a process formulas can be derived that express the\nprobability of certain events, such as the chance of returning to the origin\nafter a given number of time steps. These formulas are physically meaningful\nfor integer values of $D$. However, these formulas are unacceptable as\nprobabilities when continued to noninteger $D$ because they give values that\ncan be greater than $1$ or less than $0$. In this paper we propose a random\nwalk which gives acceptable probabilities for all real values of $D$. This\n$D$-dimensional random walk is defined on a rotationally-symmetric geometry\nconsisting of concentric spheres. We give the exact result for the probability\nof returning to the origin for all values of $D$ in terms of the Riemann zeta\nfunction. This result has a number-theoretic interpretation.",
        "positive": "Multi-block/multi-core SSOR preconditioner for the QCD quark solver for\n  K computer: We study the algorithmic optimization and performance tuning of the Lattice\nQCD clover-fermion solver for the K computer. We implement the L\\\"uscher's SAP\npreconditioner with sub-blocking in which the lattice block in a node is\nfurther divided to several sub-blocks to extract enough parallelism for the\n8-core CPU SPARC64$^{\\mathrm{TM}}$ VIIIfx of the K computer. To achieve a\nbetter convergence property we use the symmetric successive over-relaxation\n(SSOR) iteration with {\\it locally-lexicographical} ordering for the sub-blocks\nin obtaining the block inverse. The SAP preconditioner is included in the\nsingle precision BiCGStab solver of the nested BiCGStab solver. The single\nprecision part of the computational kernel are solely written with the SIMD\noriented intrinsics to achieve the best performance of the \\SPARC on the K\ncomputer. We benchmark the single precision BiCGStab solver on the three\nlattice sizes: $12^3\\times 24$, $24^3\\times 48$ and $48^3\\times 96$, with\nfixing the local lattice size in a node at $6^3\\times 12$. We observe an ideal\nweak-scaling performance from 16 nodes to 4096 nodes. The performance of a\ncomputational kernel exceeds 50% efficiency, and the single precision BiCGstab\nhas $\\sim26% susutained efficiency."
    },
    {
        "anchor": "Probing the non-perturbative dynamics of SU(2) vacuum: The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a\ngauge-invariant effective action defined using the lattice Schr\\\"odinger\nfunctional. Numerical simulations are performed both at zero and finite\ntemperature. The vacuum is probed using an external constant Abelian\nchromomagnetic field. The results suggest that at zero temperature the external\nfield is screened in the continuum limit. On the other hand at finite\ntemperature it seems that confinement is restored by increasing the strength of\nthe applied field.",
        "positive": "Lattice Investigation of the DMO Sum Rule: An evaluation of charged pion polarizability using correlation functions\nmeasured on a 16^{3}\\times 24 lattice in the context of the Das, Mathur, Okubo\n(DMO) sum rule is carried out. The calculation is limited to the so-called\nintrinsic part of the polarizability. This contribution, equivalent to a\nEuclidean time integral over vector and axial vector momentum-differentiated\npropagators, is evaluated in both a continuous and discrete sense. In the\ncontinuous case, the time behavior of the correlation functions is fit to the\ncontinuum quark model; the discrete case is handled by a straightforward\napplication of Simpson's rule for integration after subtracting the pion\ncontributions. A comparison of the implied vector meson and pion decay\nconstants with phenomenological values is carried out. Results for the\nintrinsic polarizability are extrapolated across four quark mass values to the\nchiral limit. An extensive discussion of the lattice systematics in this\ncalculation is given."
    },
    {
        "anchor": "Spectral sums of the Dirac-Wilson Operator and their relation to the\n  Polyakov loop: We investigate and compute spectral sums of the Wilson lattice Dirac operator\nfor quenched SU(3) gauge theory. It is demonstrated that there exist sums which\nserve as order parameters for the confinement-deconfinement phase transition\nand get their main contribution from the IR end of the spectrum. They are\napproximately proportional to the Polyakov loop. In contrast to earlier studied\nspectral sums some of them are expected to have a well-defined continuum limit.",
        "positive": "A pot-pourri of results in QCD from large lattice simulations on the CM5: We present a status report on simulations being done on $32^3 \\times 64$\nlattices at $\\beta = 6.0$ using quenched Wilson fermions. Results for the\nspectrum, decay constants, the kaon B-parameter $B_K$, and semi-leptonic form\nfactors are given based on the current statistical sample of 28 configurations.\nThese ``Grand Challenge'' calculations are being done on the CM5 at Los Alamos\nin collaboration with G. Kilcup, S. Sharpe and P. Tamayo. We end with a brief\nstatement of code performance."
    },
    {
        "anchor": "Thermodynamics of SU(N) gauge theories in 2+1 dimensions in the $T <\\\n  T_c$ regime: We present Monte Carlo results for the thermodynamics of pure SU(N) gauge\ntheories with $N=2,...,6$ in 2+1 dimensions. We focus on the confined phase\nregion $T<T_c$ and study thermodynamics variables such as the trace of the\nenergy-momentum tensor, pressure, energy and entropy density using the integral\nmethod. We also investigate scaling properties with $N$ of the different\nobservables. We compare our results with a gas of free glueballs and the\nbosonic string predictions for the Hagedorn spectrum.",
        "positive": "Toward numerical and analytical studies of first order phase transitions: Discrete lattice simulations of an one-dimensional phi^4 theory coupled to an\nexternal heat bath are being carried out. Great care is taken to remove the\neffects of lattice discreteness and finite size and to establish the correct\ncorrespondence between simulations and the desired, finite-temperature\ncontinuum limit."
    },
    {
        "anchor": "Simulation strategies for the massless lattice Schwinger model in the\n  dual formulation: The dual form of the massless Schwinger model on the lattice overcomes the\ncomplex action problems from two sources: a topological term, as well as\nnon-zero chemical potential, making these physically interesting cases\naccessible to Monte Carlo simulations. The partition function is represented as\na sum over fermion loops, dimers and plaquette-surfaces such that all\ncontributions are real and positive. However, these new variables constitute a\nhighly constrained system and suitable update strategies have to be developed.\nIn this exploratory study we present an approach based on locally growing\nplaquette-surfaces surrounded by fermion loop segments combined with a worm\nbased strategy for updating chains of dimers, as well as winding fermion loops.\nThe update strategy is checked with conventional simulations as well as\nreference data from exact summation on small volumes and we discuss some\nphysical implications of the results.",
        "positive": "Interactions of heavy-light mesons: The potential between static-light mesons forming a meson-meson or a\nmeson-antimeson system is calculated in quenched and unquenched SU(3) gauge\ntheory. We use the Sheikholeslami-Wohlert action and statistical estimators of\nlight quark propagators with maximal variance reduction. The dependence of the\npotentials on the light quark spin and isospin and the effect of meson exchange\nis investigated. Our main motivation is exploration of bound states of two\nmesons and string breaking. The latter also involves the two-quark potential\nand the correlation between two-quark and two-meson states."
    },
    {
        "anchor": "Universality of the Collins-Soper kernel in lattice calculations: The Collins-Soper (CS) kernel is a nonperturbative function that\ncharacterizes the rapidity evolution of transverse-momentum-dependent parton\ndistribution functions (TMDPDFs) and wave functions. In this Letter, we\ncalculate the CS kernel for pion and proton targets and for quasi-TMDPDFs of\nleading and next-to-leading power. The calculations are carried out on the CLS\nensemble H101 with dynamical $N_f=2+1$ clover-improved Wilson fermions. Our\nanalyses demonstrate the consistency of different lattice extractions of the CS\nkernel for mesons and baryons, as well as for twist-two and twist-three\noperators, even though lattice artifacts could be significant. This consistency\ncorroborates the universality of the lattice-determined CS kernel and suggests\nthat a high-precision determination of it is in reach.",
        "positive": "Method for simulating O(N) lattice models at finite density: We present a method for simulating relativistic and nonrelativistic scalar\nfield theories at finite density, with matter transforming in the fundamental\nrepresentation of the global symmetry group O(N). The method avoids the problem\nof complex probability weights which is present in conventional path integral\nMonte Carlo algorithms. To verify our approach, we simulate the free and\ninteracting relativistic U(1)=O(2) theory in 2+1 dimensions. We compute the\ntwo-point correlation function and charge density as a function of chemical\npotential in the free theory. At weak phi^4 coupling and zero temperature we\nmap the m^2-mu phase diagram and compare our numerical results with\nperturbative calculations. Finally, we compute properties of theT-mu phase\ndiagram in the vicinity of the phase transition and at bare self-couplings\nlarge compared to the temperature and chemical potential."
    },
    {
        "anchor": "The glueball spectrum at large N: The lowest-lying glueball masses are computed in SU($N$) gauge theory on a\nspacetime lattice for constant value of the lattice spacing $a$ and for $N$\nranging from 3 to 8. The lattice spacing is fixed using the deconfinement\ntemperature at temporal extension of the lattice $N_T = 6$. The calculation is\nconducted employing in each channel a variational ansatz performed on a large\nbasis of operators that includes also torelon and (for the lightest states)\nscattering trial functions. This basis is constructed using an automatic\nalgorithm that allows us to build operators of any size and shape in any\nirreducible representation of the cubic group. A good signal is extracted for\nthe ground state and the first excitation in several symmetry channels. It is\nshown that all the observed states are well described by their large $N$\nvalues, with modest ${\\cal O}(1/N^2)$ corrections. In addition spurious states\nare identified that couple to torelon and scattering operators.",
        "positive": "Lattice QED in an external magnetic field: Evidence for dynamical chiral\n  symmetry breaking: We simulate QED in a strong constant homogeneous external magnetic field on a\neuclidean space-time lattice using the Rational Hybrid Monte Carlo method,\ndeveloped for simulating lattice QCD. Our primary goal is to measure the chiral\ncondensate in the limit when the input electron mass $m$ is zero. We observe a\nnon-zero value, indicating that the external magnetic field catalyzes chiral\nsymmetry breaking as predicted by approximate truncated Schwinger-Dyson\nmethods. Such behaviour is associated with dominance by the lowest Landau level\nwhich causes the effective dimensional reduction from $3+1$~dimensions to $1+1$\ndimensions for charged particles (electrons and positrons) where the attractive\nforces of QED can produce chiral symmetry breaking with a dynamical electron\nmass and associated chiral condensate. Since our lattice simulations use bare\n(lattice) parameters, while the Schwinger-Dyson analyses work with renormalized\nquantities, direct numerical comparison will require renormalization of our\nlattice results."
    },
    {
        "anchor": "Computing the hadronic vacuum polarization function by analytic\n  continuation: We propose a method to compute the hadronic vacuum polarization function on\nthe lattice at continuous values of photon momenta bridging between the\nspacelike and timelike regions. We provide two independent demonstrations to\nshow that this method leads to the desired hadronic vacuum polarization\nfunction in Minkowski spacetime. We show with the example of the leading-order\nQCD correction to the muon anomalous magnetic moment that this approach can\nprovide a valuable alternative method for calculations of physical quantities\nwhere the hadronic vacuum polarization function enters.",
        "positive": "Probing the interior of the Colour Flux Tube: In the dual superconductivity description of quark confinement the core of\nthe flux tube connecting a quark pair belongs to a deconfined, hot phase. This\ncan be checked in numerical experiments on 3D $Z_2$ gauge model. It is also\npointed out that the Svetitsky-Yaffe conjecture provides analytic expressions\nfor the distribution of the flux density around quark sources at critical\ntemperature."
    },
    {
        "anchor": "Spatial correlators in strongly coupled plasmas: We numerically calculate the spatial correlators of the scalar and\npseudoscalar operators $F^2$ and $F\\tilde F$, in SU(3) Yang-Mills theory at\nzero and finite-temperature on the lattice. We compare the results over the\ndistances $\\frac{1}{2T}<r<\\frac{3}{2T}$ to the free-field prediction, to the\noperator-product expansion as well as to the strongly coupled large-$N_c$\n$\\sN=4$ super-Yang-Mills theory, where results are obtained by AdS/CFT methods.\nFor $T_c<T<1.15T_c$, both channels exhibit stronger spatial correlations than\nin the vacuum, and we give an explanation for this, using sum-rules and the\noperator-product expansion. The AdS/CFT calculation provides a\nsemi-quantitatively successful description of the vacuum-subtracted $F^2$\ncorrelator, renormalized in the 3-loop $\\overline{\\rm MS}$ scheme, in the\ninterval of temperatures $1.2<T/T_c<1.9$, while the free-field prediction has\nthe wrong sign. The $F\\tilde F$ and $F^2$ correlators are predicted to have the\nsame functional form both at weak coupling and in the strongly coupled SYM\ntheory. The Yang-Mills plasma does not meet that expectation below $2T_c$.\nInstead we find that strong fluctuations of $F\\tilde F$ are present at least up\nto that temperature. We discuss the impact of our results on our understanding\nof the quark-gluon plasma.",
        "positive": "Lattice QCD evaluation of the Compton amplitude employing the\n  Feynman-Hellmann theorem: The forward Compton amplitude describes the process of virtual photon\nscattering from a hadron and provides an essential ingredient for the\nunderstanding of hadron structure. As a physical amplitude, the Compton tensor\nnaturally includes all target mass corrections and higher twist effects at a\nfixed virtuality, $Q^2$. By making use of the second-order Feynman-Hellmann\ntheorem, the nucleon Compton tensor is calculated in lattice QCD at an\nunphysical quark mass across a range of photon momenta $3 \\lesssim Q^2 \\lesssim\n7$ GeV$^2$. This allows for the $Q^2$ dependence of the low moments of the\nnucleon structure functions to be studied in a lattice calculation for the\nfirst time. The results demonstrate that a systematic investigation of power\ncorrections and the approach to parton asymptotics is now within reach."
    },
    {
        "anchor": "Large scale numerical simulation of the three-state Potts model: The three-state Potts model is numerically investigated on three-dimensional\nsimple cubic lattices of up to \\(128^3\\) volume, concentrating on the\nneighborhood of the first-order phase transition separating the ordered and\ndisordered phases. The ordered phase is found to allow admixture of disordered\ndomains induced by a long-range attraction acting between the two different\nnon-favored spins. This phenomenon gives an explanation of why the first-order\nphase transitions associated with the global \\(Z_3\\) symmetry are so weak.\n(Talk given at the International Symposium \"Lattice 92\" in Amsterdam, September\n15-19, 1992)",
        "positive": "Gauge-independent derivation of \"Abelian\" dominance and magnetic\n  monopole dominance in the string tension: Recently, we have developed a reformulation of the lattice Yang-Mills theory\nbased on the change of variables a la Cho-Faddeev-Niemi combined with a\nnon-Abelian Stokes theorem. In this talk, we give a new procedure (called\nreduction) for obtaining the color field which plays the central role in this\nreformulation. In the 4D SU(2) lattice Yang-Mills theory, we confirm the\ngauge-independent \"abelian\" dominance and gauge-independent magnetic-monopole\ndominance in the string tension extracted from the Wilson loop in the\nfundamental representation."
    },
    {
        "anchor": "Scalar and axial vector matrix elements of proton in quenched QCD:\n  Calculation of both connected and disconnected contributions: $\\pi$-$N$ $\\sigma$ term and proton axial vector matrix elements are\ncalculated including disconnected contributions with a variant wall source\nmethod using the Wilson quark action at $\\beta=5.7$ in quenched QCD. For the\n$\\sigma$ term, we find $\\sigma_{disc}/\\sigma_{conn}=2.35(46)$ and\n$\\sigma=44(6)$MeV--60(9)MeV. The fraction of proton spin carried by quarks is\n$\\Delta\\Sigma=\\Delta{u}+\\Delta{d}+\\Delta{s}=+0.638(54)-0.347(46)-0.109(30)=\n+0.18(10)$.",
        "positive": "Patterns of Spontaneous Chiral Symmetry Breaking in Vectorlike Gauge\n  Theories: It has been conjectured that spontaneous chiral symmetry breaking in strongly\ncoupled vectorlike gauge theories falls into only three different classes,\ndepending on the gauge group and the representations carried by the fermions.\nWe test this proposal by studying SU(2), SU(3) and SU(4) lattice gauge theories\nwith staggered fermions in different irreducible representations. Staggered\nfermions away from the continuum limit should, for all complex representations,\nstill belong to the continuum class of spontaneous symmetry breaking. But for\nall real and pseudo-real representations we show that staggered fermions should\nbelong to incorrect symmetry breaking classes away from the continuum, thus\ngeneralizing previous results. As an unambiguous signal for whether chiral\nsymmetry breaks, and which breaking pattern it follows, we look at the smallest\nDirac eigenvalue distributions. We find that the patterns of symmetry breaking\nare precisely those conjectured."
    },
    {
        "anchor": "Influence of relativistic rotation on the confinement/deconfinement\n  transition in gluodynamics: In this paper we consider the influence of relativistic rotation on the\nconfinement/deconfinement transition in gluodynamics within lattice simulation.\nWe perform the simulation in the reference frame which rotates with the system\nunder investigation, where rotation is reduced to external gravitational field.\nTo study the confinement/deconfinement transition the Polyakov loop and its\nsusceptibility are calculated for various lattice parameters and the values of\nangular velocities which are characteristic for heavy-ion collision\nexperiments. Different types of boundary conditions (open, periodic, Dirichlet)\nare imposed in directions, orthogonal to rotation axis. Our data for the\ncritical temperature are well described by a simple quadratic function\n$T_c(\\Omega)/T_c(0) = 1 + C_2 \\Omega^2$ with $C_2>0$ for all boundary\nconditions and all lattice parameters used in the simulations. From this we\nconclude that the critical temperature of the confinement/deconfinement\ntransition in gluodynamics increases with increasing angular velocity. This\nconclusion does not depend on the boundary conditions used in our study and we\nbelieve that this is universal property of gluodynamics.",
        "positive": "The topological objects near the chiral crossover transition in QCD: We study the underlying topology of gauge fields in 2+1 flavor QCD with\ndomain wall fermions on lattices of size $32^3\\times 8$, at and immediately\nabove the chiral crossover transition. Using valence overlap fermions with\nexact index theorem, we focus on its zero modes for different choices of\nperiodicity phases along the temporal direction. Our studies show that the zero\nmodes are due to fractionally charged topological objects, the instanton-dyons.\nWe further provide qualitative study of the interactions between those and\ncompare with the available semi-classical results, finding remarkably accurate\nagreement in all cases."
    },
    {
        "anchor": "Abelian Projection without Ambiguities: Laplacian Abelian Projection is discussed. This term refers to the use of a\nnew (``Laplacian'') gauge fixing prescription for implementing the Abelian\nProjection of QCD. The gauge condition is based on the lowest-lying eigenvector\nof the covariant Laplacian operator in the adjoint representation.\n  This Laplacian gauge fixing procedure is free of the ambiguities which plague\nlattice simulations which work with the popular Maximally Abelian Gauge.\nFurthermore, Laplacian gauge fixed configurations enjoy a natural kind of\nsmoothness. These two properties are crucial for a reliable determination of\nphysical quantities using the Abelian Projection.\n  We also examine a new, Higgs-field-like observable which emerges as a\nby-product of the method. This quantity can be used to identify magnetic\nmonopoles in a way independent of the traditional prescription. It is argued\nthat physically relevant magnetic monopoles are accomodated well by the\nLaplacian method, while they are suppressed (too) strongly in Maximally Abelian\nGauge.\n  Finally, first evidence of abelian dominance in the Laplacian Abelian\nProjection is presented.",
        "positive": "Another determination of the quark condensate from an overlap action: I use the technique of Hernandez, et al (hep-lat/0106011) to convert a recent\ncalculation of the lattice-regulated quark condensate from an overlap action to\na continuum-regulated number. I find Sigma(MSbar)(mu = 2 GeV) = (282(6)\nMeV)-cubed times (a-inverse/1766 MeV)-cubed from a calculation with the Wilson\ngauge action at beta=5.9."
    },
    {
        "anchor": "Spin Polarizabilities on the Lattice: Spin polarizabilities provide information on the internal structure of\nhadrons in the presence of weak external electromagnetic fields, and are\nactively studied by Compton scattering experiments. They provide finer detail\nthan the regular polarizabilities since they require space and time-varying\nfields. Using an effective action in the weak field limit, we have identified\nmethods to isolate each of the physical quantities ($\\mu, \\alpha, \\beta,\n\\gamma_{E1}, \\gamma_{M1}, \\gamma_{E2}, \\gamma_{M2}$) for spin-1/2 hadrons, both\nneutral and charged. We also perform a lattice QCD simulation to investigate\nthe feasibility of the effective action approach.",
        "positive": "Continuous Time Simulations of Strong Coupling LQCD at Finite Baryon\n  Density: We study lattice QCD in the limit of infinite gauge coupling on a discrete\nspatial yet continuous Euclidean time lattice at finite baryon chemical\npotential $\\mu_B$. The continuous time framework is based on sending\n$N_\\tau\\rightarrow \\infty$ and the bare anisotropy to infinity while fixing the\ntemperature in a non-perturbative setup. This leads to a sign problem free\nalgorithm that allows us to study the whole $\\mu_B$-$T$ plane. We construct\nTaylor coefficients required for a Taylor expansion in the pressure at zero\nchemical potential and in the chiral limit. On that account, cumulants in the\nbaryon number density are measured in various fashions to improve on accuracy.\nThese calculations are based on our worm type Monte Carlo algorithm featuring a\npolymer resummation scheme and a histogram method."
    },
    {
        "anchor": "PC Clusters for Lattice QCD: In the last several years, tightly coupled PC clusters have become widely\napplied, cost effective resources for lattice gauge computations. This paper\ndiscusses the practice of building such clusters, in particular balanced design\nrequirements. I review and quantify the improvements over time of key\nperformance parameters and overall price to performance ratio. Applying these\ntrends and technology forecasts given by computer equipment manufacturers, I\npredict the range of price to performance for lattice codes expected in the\nnext several years.",
        "positive": "Is the 2D O(3) Nonlinear $\u03c3$ Model Asymptotically Free?: We report the results of a Monte Carlo study of the continuum limit of the\ntwo dimensional O(3) non-linear $\\sigma$ model. The notable finding is that it\nagrees very well with both the prediction inspired by Zamolodchikovs' S-matrix\nansatz and with the continuum limit of the dodecahedron spin model. The latter\nfinding renders the existence of asymptotic freedom in the O(3) model rather\nunlikely."
    },
    {
        "anchor": "Non-perturbative evaluation of cSW for smeared link clover fermion and\n  Iwasaki gauge action: We performed a rough estimate of the non-perturbative value of the clover\nterm coefficient cSW for the APE stout link Wilson fermion. We varied the\nnumber of smearings from Nsmear=1 to 6 and adopted beta values roughly\ncorresponding to the lattice spacing of 0.1 fm. We used the Schroedinger\nfunctional technique for an evaluation of cSW and found that cSW decreases\nmonotonically as we increase Nsmear but has a 10% order of deviation from the\ntree level value for Nsmear=6.",
        "positive": "Instantons and Monte Carlo Methods in Quantum Mechanics: In these lectures we describe the use of Monte Carlo simulations in\nunderstanding the role of tunneling events, instantons, in a quantum mechanical\ntoy model. We study, in particular, a variety of methods that have been used in\nthe QCD context, such as Monte Carlo simulations of the partition function,\ncooling and heating, the random and interacting instanton liquid model, and\nnumerical simulations of non-Gaussian corrections to the semi-classical\napproximation."
    },
    {
        "anchor": "Deconstruction, 2d lattice super-Yang-Mills, and the dynamical lattice\n  spacing: We study expectation values related to the dynamical lattice spacing that\noccurs in the recent 2d lattice super-Yang-Mills constructions of Cohen et al.\n[hep-lat/0307012]. The corresponding observable in the fully-quenched ensemble\nwould appear to indicate a difficulty with the proposed continuum limit.\nHowever, we find that the same observable in the phase-quenched ensemble takes\na very different, perhaps encouraging, average value. Unfortunately, we are not\nable to obtain results for the full theory, due to the nearly flat distribution\nof the complex phase of the fermion determinant in the phase-quenched ensemble.",
        "positive": "Geometric representation of the 2D Antiferromagnetic Ising Model with\n  topological term at \u03b8=\u03c0: We study the two-dimensional Antiferromagnetic Ising Model with an imaginary\nmagnetic field i\\theta at \\theta=\\pi. We use a new geometric algorithm which\ndoes not present a sign problem. This allows us to perform efficient numerical\nsimulations of this system."
    },
    {
        "anchor": "Summary of Super Doubler Approach on Exact Lattice Supersymmetry: We have proposed a lattice SUSY formulation which we may call super doubler\napproach, where chiral fermion species doublers and their bosonic counter parts\nare either identified as super partners or truncated by chiral conditions. We\nclaim that the super symmetry is exactly kept on the lattice. However the\nformulation is nonlocal and breaks lattice translational invariance. We argue\nthat these features cause no fundamental difficulties in the continuum limit.\nAlthough a naive version of this formulation breaks associativity of the\nproduct of fields we have found a modified super doubler approach that recovers\nthe associativity and is applicable to super Yang-Mills theory. It turns out\nthat this formulation is essentially equivalent to the continuum formulation\nand thus keeps all the symmetry exact even at a finite lattice constant.\nInspired by this formulation we propose a non-local lattice field theory\nformulation which is free of chiral fermion problem and has the same exact\nlattice symmetry as continuum theory.",
        "positive": "Static Friction Phenomena in Granular Materials: Coulomb Law vs.\n  Particle Geometry: The static as well as the dynamic behaviour of granular material are\ndetermined by dynamic {\\it and} static friction. There are well known methods\nto include static friction in molecular dynamics simulations using scarcely\nunderstood forces. We propose an Ansatz based on the geometrical shape of\nnonspherical particles which does not involve an explicit expression for static\nfriction. It is shown that the simulations based on this model are close to\nexperimental results."
    },
    {
        "anchor": "The large N limit of four dimensional Yang-Mills field coupled to\n  adjoint fermions on a single site lattice: We consider the large N limit of four dimensional SU(N) Yang-Mills field\ncoupled to adjoint fermions on a single site lattice. We use perturbative\ntechniques to show that the Z^4_N center-symmetries are broken with naive\nfermions but they are not broken with overlap fermions. We use numerical\ntechniques to support this result. Furthermore, we present evidence for a\nnon-zero chiral condensate for one and two Majorana flavors at one value of the\nlattice gauge coupling.",
        "positive": "The pion-nucleon sigma term from lattice QCD: We present an analysis of the pion-nucleon $\\sigma$-term, $\\sigma_{\\pi N}$,\nusing six ensembles with 2+1+1-flavor highly improved staggered quark action\ngenerated by the MILC collaboration. The most serious systematic effect in\nlattice calculations of nucleon correlation functions is the contribution of\nexcited states. We estimate these using chiral perturbation theory ($\\chi$PT),\nand show that the leading contribution to the isoscalar scalar charge comes\nfrom N$\\pi$ and N$\\pi\\pi$ states. Therefore, we carry out two analyses of\nlattice data to remove excited-state contamination, the standard one and a new\none including N$\\pi$ and N$\\pi\\pi$ states. We find that the standard analysis\ngives $\\sigma_{\\pi N} = 41.9(4.9)$ MeV, consistent with previous lattice\ncalculations, while our preferred $\\chi$PT-motivated analysis gives\n$\\sigma_{\\pi N} = 59.6(7.4)$ MeV, which is consistent with phenomenological\nvalues obtained using $\\pi$N scattering data. Our data on one physical pion\nmass ensemble was crucial for exposing this difference, therefore, calculations\non additional physical mass ensembles are needed to confirm our result and\nresolve the tension between lattice QCD and phenomenology."
    },
    {
        "anchor": "Recent results on the meson and baryon spectrum from lattice QCD: Recent lattice results on the meson and baryon spectrum with a focus on the\ndetermination of hadronic resonance masses and widths using a combined basis of\nsingle-hadron and hadron-hadron interpolating fields are reviewed. These mostly\nexploratory calculations differ from traditional lattice QCD spectrum\ncalculations for states stable under QCD, where calculations with a full\nuncertainty estimate are already routinely performed. Progress and challenges\nin these calculations are highlighted.",
        "positive": "Helicity modulus as renormalized coupling in the O(3) sigma-model: For the family of O(n) invariant nonlinear sigma-models we consider boundary\nconditions that are periodic up to an O(n) rotation. The helicity modulus is\nrelated to the change in free energy under variations of the corresponding\nangle. It defines a nonperturbative finite volume running coupling similar to\nthe Schr\"odinger functional for QCD. For the two-dimensional O(3)-model we\ninvestigate this quantity by analytical and numerical techniques. We establish\nits universal continuum relation to the finite volume massgap coupling at all\nscales and coupling strengths."
    },
    {
        "anchor": "Studies in Random Geometries: Hypercubic Random Surfaces and Simplicial\n  Quantum Gravity: We analyze two models of random geometries~: planar hyper-cubic random\nsurfaces and four dimensional simplicial quantum gravity.\n  We show for the hyper-cubic random surface model that a geometrical\nconstraint does not change the critical properties of the model compared to the\nmodel without this constraint. We analyze the phase diagram for the model with\nextrinsic curvature.\n  For four dimensional simplicial quantum gravity we find that in the large\nvolume limit the leading contribution to the entropy does not depend on the\nunderlying topology. We find for the first time a strong back-reaction of the\ngeometric sector for matter coupled to gravity.",
        "positive": "Towards Novel Insights in Lattice Field Theory with Explainable Machine\n  Learning: Machine learning has the potential to aid our understanding of phase\nstructures in lattice quantum field theories through the statistical analysis\nof Monte Carlo samples. Available algorithms, in particular those based on deep\nlearning, often demonstrate remarkable performance in the search for previously\nunidentified features, but tend to lack transparency if applied naively. To\naddress these shortcomings, we propose representation learning in combination\nwith interpretability methods as a framework for the identification of\nobservables. More specifically, we investigate action parameter regression as a\npretext task while using layer-wise relevance propagation (LRP) to identify the\nmost important observables depending on the location in the phase diagram. The\napproach is put to work in the context of a scalar Yukawa model in (2+1)d.\nFirst, we investigate a multilayer perceptron to determine an importance\nhierarchy of several predefined, standard observables. The method is then\napplied directly to the raw field configurations using a convolutional network,\ndemonstrating the ability to reconstruct all order parameters from the learned\nfilter weights. Based on our results, we argue that due to its broad\napplicability, attribution methods such as LRP could prove a useful and\nversatile tool in our search for new physical insights. In the case of the\nYukawa model, it facilitates the construction of an observable that\ncharacterises the symmetric phase."
    },
    {
        "anchor": "A method to study complex systems of mesons in Lattice QCD: Finite density systems can be explored with Lattice QCD through the\ncalculation of multi-hadron correlation functions. Recently, systems with up to\n12 $\\pi^+$'s or $K^+$'s have been studied to determine the 3-$\\pi^+$ and\n3-$K^+$ interactions, and the corresponding chemical potentials have been\ndetermined as a function of density. We derive recursion relations between\ncorrelation functions that allow this work to be extended to systems of\narbitrary numbers of mesons and to systems containing many different types of\nmesons, such as $\\pi^+$'s, $K^+$'s, $\\bar{D}^0$'s and $B^+$'s. These relations\nallow for the study of finite-density systems in arbitrary volumes, and for the\nstudy of high-density systems.",
        "positive": "Lattice Effective Actions and Light-Quark Confinement: The positive-plaquette Manton action at weak coupling is a reasonable action\nfor short-distance phenomena. We propose an iterative scheme for evolving this\naction into an effective action for longer distance scales. We report on the\nfirst step of this scheme in which we have measured ``blocked'' Creutz ratios\nwith lattice spacing 2a at beta = 16 on a 32^4 lattice and have searched for an\neffective action that yields the same ratios on a 16^4 lattice.\n  We also suggest a mechanism for quark confinement that relies upon the\nlightness of the u and d quarks and formulate a way of testing it in lattice\nsimulations of QCD."
    },
    {
        "anchor": "Isospin 0 and 2 two-pion scattering at physical pion mass using\n  distillation with periodic boundary conditions in lattice QCD: The two pion channel in Lattice QCD has long been a primary testing ground\nfor studying multiparticle scattering in finite volume QCD. With the\ndevelopment of sophisticated techniques such as distillation, it is possible to\ncarefully study two-pion scattering in order to constrain associated low-energy\nconstants. In this work, correlation functions with multiparticle interpolating\noperators are constructed to compute pion scattering phase shifts and\nscattering lengths in the isospin 0 and 2 channels with both sea and valence\nquarks at physical mass. Contamination from vacuum and thermal contributions\nare explicitly quantified with dedicated calculations and the results obtained\nafter subtracting these nuisance terms are compared with the traditional\ncorrelator time series subtraction method. Two physical point ensembles with\ndifferent lattice actions are used, and our finest ensemble gives results for\nscattering lengths and phase shifts consistent with phenomenology to within the\nreported statistical uncertainty.",
        "positive": "Mixed Model of Induced QCD: The problems with the $Z_N$ symmetry breaking in the induced QCD are\nanalyzed. We compute the Wilson loops in the strong coupling phase, but we do\nnot find the $Z_N$ symmetry breaking, for arbitrary potential. We suggest to\nbypass this problem by adding to the model a heavy fermion field in a\nfundamental representation of $ SU(N) $. Remarkably, the model still can be\nsolved exactly by the Rieman-Hilbert method, for arbitrary number $N_f$ of\nflavors. At $ N_f \\ll N \\rightarrow \\infty $ there is a new regime, with two\nvacuum densities. The $Z_N$ symmetry breaking density satisfies the linear\nintegral equation, with the kernel, depending upon the old density. The\nsymmetry breaking requires certain eigenvalue condition, which takes some extra\nparameter adjustment of the scalar potential."
    },
    {
        "anchor": "The topological susceptibility slope $\u03c7^\\prime$ of the pure-gauge\n  SU(3) Yang-Mills theory: We determine the pure-gauge $\\mathrm{SU}(3)$ topological susceptibility slope\n$\\chi^\\prime$, related to the next-to-leading-order term of the momentum\nexpansion of the topological charge density 2-point correlator, from numerical\nlattice Monte Carlo simulations. Our strategy consists in performing a\ndouble-limit extrapolation: first we take the continuum limit at fixed\nsmoothing radius, then we take the zero-smoothing-radius limit. Our final\nresult is $\\chi^\\prime = [17.1(2.1)~\\mathrm{MeV}]^2$. We also discuss a\ntheoretical argument to predict its value in the large-$N$ limit, which turns\nout to be remarkably close to the obtained $N=3$ lattice result.",
        "positive": "A lattice fermion without doubling: A free fermion without doubler is formulated on 1+D dimensional discrete\nMinkowski space-time. The action is not hermitian but causes no harm. In 1+3\ndimensional massless case the equation describes a single species of Dirac\nparticle in the continuous space-time limit. In 1+1 dimensional massless case\nthe equation is the same as the automaton equation by 't Hooft and describes a\nchiral fermion. The time evolution operator is unitary and the norm is\nconserved. For interacting fermions with gauge fields the evolution operator is\nnot unitary. If it is considered as an approximation for the theory on\ncontinuous space-time, the path integral formalism can be applied, where the\nfermion without doubling is used. Consequences of loosening the unitarity\ncondition on the time evolution operator is discussed."
    },
    {
        "anchor": "A Study of Charmonium Systems across the Deconfinement Transition: We present results from lattice studies of charmonium systems near the\ndeconfinement transition temperature. On quenched isotropic lattices with\nlattice spacings between 0.02 and 0.05 fm, bar{q} q systems with quark masses\nclose to the charm mass and with different spin-parity quantum numbers are\nstudied in the temperature range 0.9 Tc - 3 Tc. Results for temporal\ncorrelators of local operators, and the spectral functions constructed from\nthem, are discussed. For the pseudoscalar and vector channels, the correlators\nare observed to change very little across the deconfinement transition, unlike\nin the case of the light quarks.",
        "positive": "Numerical Analysis of Discretized ${\\cal N}=(2,2)$ SYM on Polyhedra: We perform a numerical simulation of the two-dimensional ${\\cal N}=(2,2)$\nsupersymmetric Yang-Mills (SYM) theory on the discretized curved space. The\n$U(1)_{A}$ anomaly of the continuum theory is maintained also in the\ndiscretized theory as an unbalance of the number of the fermions. In the\nprocess, we propose a new phase-quenched approximation, which we call the\n\"anomaly-phase-quenched (APQ) method\", to make the partition function and\nobservables well-defined by $U(1)_{A}$ phase cancellation. By adopting APQ\nmethod, we estimate the Ward-Takahashi identity for exact SUSY on lattice and\nclarify contribution of the pseudo zero-modes to the pfaffian phase."
    },
    {
        "anchor": "Two-Baryon Systems with Twisted Boundary Conditions: I derive the most general quantization condition for energy eigenvalues of\ntwo interacting baryons in a finite cubic volume when arbitrary twisted\nboundary conditions are imposed on their finite-volume wavefunctions. These\nquantization conditions are used, along with experimentally known scattering\nparameters of two-nucleon systems in the coupled 3S1-3D1 channels, to\ndemonstrate the expected effect of a selection of twisted boundary conditions\non the spectrum of the deuteron. It is shown that an order of magnitude\nreduction in the finite-volume corrections to the deuteron binding energy arise\nin moderate volumes with a proper choice of boundary conditions on the proton\nand the neutron, or by averaging the result of periodic and anti-periodic\nboundary conditions. These observations mean that a sub-percent accuracy can be\nachieved in the determination of the deuteron binding energy at (spatial)\nvolumes as small as ~(9[fm])^3 in upcoming lattice QCD calculations of this\nnucleus with physical light-quark masses. The results reviewed in this talk are\npresented in details in Ref. [1].",
        "positive": "The step scaling function of QCD at negative flavor number: As a computationally less costly test case for full QCD, we investigate an\nSU(3) Yang-Mills theory coupled to a bosonic spinor field. This theory\ncorresponds to QCD with minus two quark flavors and is known as the bermion\nmodel. Our central object of interest is the step scaling function which\ndescribes the scale evolution of the running coupling in the Schrodinger\nfunctional scheme. We develop a suitable algorithm for the simulation of O(a)\nimproved bermions and compare its performance with unimproved bermions and full\nQCD. We study in detail the lattice artefacts and the continuum extrapolation\nof the step scaling function from lattice simulations when improvement is used.\nOur results are compared to the unimproved bermion and dynamical fermion cases,\nand to renormalized perturbation theory in the continuum limit.\n  We also examine the step scaling function with massive quarks in the bermion\nmodel. According to the Appelquist-Carazzone theorem the contributions from\nmatter fields are expected to vanish for large masses, such that the step\nscaling function converges to the pure gauge theory case. If one wants to\nconnect non-perturbatively different effective theories with different numbers\nof active quarks over flavor thresholds, lattice artefacts should be reasonably\nsmall. In order to test the feasibility of such a method, we investigate the\nstep scaling function and its lattice artefacts for several values of the mass."
    },
    {
        "anchor": "The QCD chiral phase transition from non-integer numbers of flavors: Attempts to extract the order of the chiral transition of QCD at zero\nchemical potential, with two dynamical flavors of massless quarks, from\nsimulations with progressively decreasing pion mass have remained inconclusive\nbecause of their increasing numerical cost. In an alternative approach to this\nproblem, we consider the path integral as a function of continuous number\n$N_\\text{f}$ of degenerate quarks. If the transition in the chiral limit is\nfirst-order for $N_\\text{f} \\ge 3$, a second-order transition for\n$N_\\text{f}=2$ then requires a tricritical point in between. This in turn\nimplies tricritical scaling of the critical boundary line between the\nfirst-order and crossover regions as the chiral limit is approached.\nNon-integer numbers of fermion flavors are easily implemented within the\nstaggered fermion discretization. Exploratory simulations at $\\mu=0$ and\n$N_\\text{f} = 2.8, 2.6, 2.4, 2.2, 2.1$, on coarse $N_\\tau = 4$ lattices, indeed\nshow a smooth variation of the critical mass mapping out a critical line in the\n$(m,N_\\text{f})$-plane. For the smallest masses the line appears consistent\nwith tricritical scaling, allowing for an extrapolation to the chiral limit.",
        "positive": "Measuring the Topological Susceptibility in a Fixed Sector: For field theories with a topological charge Q, it is often of interest to\nmeasure the topological susceptibility chi_t = ( < Q^2 > - < Q >^2 ) / V. If we\nmanage to perform a Monte Carlo simulation where Q changes frequently, chi_t\ncan be evaluated directly. However, for local update algorithms and fine\nlattices, the auto-correlation time with respect to Q tends to be extremely\nlong, which invalidates the direct approach. Nevertheless, the measurement of\nchi_t is still feasible, even when the entire Markov chain is topologically\nfrozen. We test a method for this purpose, based on the correlation of the\ntopological charge density, as suggested by Aoki, Fukaya, Hashimoto and Onogi.\nOur studies in non-linear sigma-models and in 2d Abelian gauge theory yield\naccurate results for chi_t, which confirm that the method is applicable. We\nalso obtain promising results in 4d SU(2) Yang-Mills theory, which suggest the\napplicability of this method in QCD."
    },
    {
        "anchor": "Exploring the Unstable Modes Dynamics by the Lattice Schrodinger\n  Functional: We analyze the problem of the Nielsen-Olesen unstable modes in the $SU(2)$\nlattice gauge theory by means of a recently introduced gauge-invariant\neffective action. We perform numerical simulations in the case of a constant\nAbelian chromomagnetic field. We find that for lattice sizes above a certain\ncritical length the density of effective action shows a behaviour compatible\nwith the presence of the unstable modes.",
        "positive": "Dirac-mode analysis for quark number density and its application for\n  deconfinement transition: The quark number density at finite imaginary chemical potential is\ninvestigated in the lattice QCD using the Dirac-mode expansion. We find the\nanalytical formula of the quark number density in terms of the Polyakov loop in\nthe large quark mass regime. On the other hand, in the small quark mass region,\nthe quark number density is investigated by using the quenched lattice QCD\nsimulation. The quark number density is found to strongly depend on the\nlow-lying Dirac modes while its sign does not change. This result leads to that\nthe quark number holonomy is not sensitive to the low-lying Dirac modes. We\ndiscuss the confinement-deconfinement transition from the property of the quark\nnumber density and the quark number holonomy."
    },
    {
        "anchor": "Flavour blindness and patterns of flavour symmetry breaking in lattice\n  simulations of up, down and strange quarks: QCD lattice simulations with 2+1 flavours (when two quark flavours are mass\ndegenerate) typically start at rather large up-down and strange quark masses\nand extrapolate first the strange quark mass and then the up-down quark mass to\nits respective physical value. Here we discuss an alternative method of tuning\nthe quark masses, in which the singlet quark mass is kept fixed. Using group\ntheory the possible quark mass polynomials for a Taylor expansion about the\nflavour symmetric line are found, first for the general 1+1+1 flavour case and\nthen for the 2+1 flavour case. This ensures that the kaon always has mass less\nthan the physical kaon mass. This method of tuning quark masses then enables\nhighly constrained polynomial fits to be used in the extrapolation of hadron\nmasses to their physical values. Numerical results for the 2+1 flavour case\nconfirm the usefulness of this expansion and an extrapolation to the physical\npion mass gives hadron mass values to within a few percent of their\nexperimental values. Singlet quantities remain constant which allows the\nlattice spacing to be determined from hadron masses (without necessarily being\nat the physical point). Furthermore an extension of this programme to include\npartially quenched results is given.",
        "positive": "Axial charges of excited nucleons from CI-fermions: We report lattice QCD results on the axial charges of ground and excited\nnucleon states of both parities. This is the first study of these quantities\nwith approximately chiral (CI) fermions. Two energy levels in the range of the\nnegative parity resonances N*(1535) and N*(1650) are observed and we determine\nthe axial charge for both. We obtain a small axial charge for one of them,\nwhich is consistent with the chiral symmetry restoration in this state as well\nas with the small axial charge of the N*(1535) predicted within the quark\nmodel. This result agrees with the findings of Takahashi et al. obtained with\nWilson quarks which violate chiral symmetry for finite lattice spacing. At the\nsame time for the other observed negative parity state we obtain a large axial\ncharge, that is close to the axial charge of the nucleon. This is in\ndisagreement both with the quark model prediction as well as with the chiral\nrestoration but allows for an interpretation as an s-wave {\\pi} N state."
    },
    {
        "anchor": "Bethe-Salpeter wave functions of $\u03b7_c(2S)$ and $\u03c8(2S)$ states from\n  full lattice QCD: We discuss the internal structure of radially excited charmonium mesons based\non the equal-time and Coulomb gauge Bethe-Salpeter (BS) amplitudes, which are\nobtained in lattice QCD. Our simulations are performed with a relativistic\nheavy-quark action for the charm quark on the 2+1 flavor PACS-CS gauge\nconfigurations at the lightest pion mass, $M_{\\pi}=156(7)$ MeV. The variational\nmethod is applied to the study of optimal charmonium operator for ground and\nfirst excited states of $S$-wave charmonia. We successfully calculate the BS\nwave functions of $\\eta_c(2S)$ and $\\psi(2S)$ states, as well as $\\eta_c(1S)$\nand $J/\\psi$ states, and then estimate the root-mean-square radii of both the\n$1S$ and $2S$ charmonium states. We also examine whether a series of the BS\nwave functions from the ground state to excited states can be described by a\nsingle set of the spin-independent and spin-dependent interquark potentials\nwith a unique quark mass. It is found that the quark kinetic mass and, both the\ncentral and spin-spin charmonium potentials, determined from the $2S$ wave\nfunctions, fairly agree with the ones from the $1S$ wave functions. This\nstrongly supports the validity of the potential description for the charmonium\nsystem, at least, below open-charm threshold.",
        "positive": "Chirally improving Wilson fermions III. The Schr\u00f6dinger functional: We show that it is possible to construct a lattice Schroedinger functional\nfor standard Wilson fermions, where the expectation values of ${\\cal R}_5$-even\noperators are O($a$) improved, up to terms coming from the boundaries."
    },
    {
        "anchor": "Local spin description of fermions on a lattice: A local transformation from fermionic operators to spin matrices is proposed\nand studied in this work. For this purpose, a system of fermions on a lattice\nis considered and one applies the scheme to replace the fermionic variables\nwith spin matrices, while the transformation relates only those fermionic/spin\noperators which are assigned to nearby lattice sites. In one dimension, this\nproposal yields the same result as the well-known Jordan-Wigner transformation,\nwhile not being restricted to $d=1$ dimension. To obtain the equivalent\ndescription in the spin picture, one needs to impose constraints on the spin\nspace. Since finding the reduced spin Hilbert space constitutes a substantial\nstage of the whole procedure, the constraints are paid particular attention.\nThe full set of necessary constraints is determined in both representations. To\napproach the task to solve the constraints, a suitable basis is constructed.\nThe introduction of the basis in the spin representation along with the\nconstruction of the constraints and the Hamiltonian in this basis show how the\ntransformation proposed in this work can be applied to obtain observables in\nthe spin picture. Explicit construction of the constraints in the basis allows\none to solve them and, once the basis vectors of the reduced spin Hilbert space\nare found, the spin Hamiltonian is expressed in this basis and diagonalized.\nThe constraints are constructed in the basis as discussed above and analyzed\nwith the Wolfram Mathematica programs for lattice sizes $3\\times3$, $4\\times3$\nand $4\\times4$. Their mutual relations are determined and the reduced spin\nHilbert space is specified. The Hamiltonian is constructed in this\nrepresentation and diagonalized. It is verified that the eigenenergies obtained\nin the spin picture agree with the analytic formulas from the fermionic\nrepresentation.",
        "positive": "The high density region of QCD in a large mass and chemical potential\n  model: We study the high density region of QCD within an effective model obtained in\nthe frame of the hopping parameter expansion. The model still acknowledges the\nsign problem peculiar to non-zero chemical potential, but it permits the\ndevelopment of refined algorithms which ensure a good overlap of the Monte\nCarlo ensemble with the true one. We review the main features of the model,\nincluding the most explicit form of the resumed expansion, and present\ncalculations concerning the dependence of various observables on the chemical\npotential and on the temperature, in particular of the charge density and the\ndiquark susceptibility, which may be used to characterize the various phases\nexpected at high baryonic density."
    },
    {
        "anchor": "Magnetic susceptibility of QCD matter and its decomposition from the\n  lattice: We determine the magnetic susceptibility of thermal QCD matter by means of\nfirst principles lattice simulations using staggered quarks with physical\nmasses. A novel method is employed that only requires simulations at zero\nbackground field, thereby circumventing problems related to magnetic flux\nquantization. After a careful continuum limit extrapolation, diamagnetic\nbehavior (negative susceptibility) is found at low temperatures and strong\nparamagnetism (positive susceptibility) at high temperatures. We revisit the\ndecomposition of the magnetic susceptibility into spin- and orbital angular\nmomentum-related contributions. The spin term -- related to the normalization\nof the photon lightcone distribution amplitude at zero temperature -- is\ncalculated non-perturbatively and extrapolated to the continuum limit. Having\naccess to both the full magnetic susceptibility and the spin term, we calculate\nthe orbital angular momentum contribution for the first time. The results\nreveal the opposite of what might be expected based on a free fermion picture.\nWe provide a simple parametrization of the temperature- and magnetic\nfield-dependence of the QCD equation of state that can be used in\nphenomenological studies.",
        "positive": "PDFs and Neutrino-Nucleon Scattering from Hadronic Tensor: We review the Euclidean path-integral formulation of the nucleon hadronic\ntensor and classify the gauge invariant and topologically distinct insertions\nin terms of connected and disconnected insertions and also in terms of leading\nand higher-twist contributions in the DIS region. Converting the Euclidean\nhadronic tensor back to the Minkowski space requires solving an inverse problem\nof the Laplace transform. We have investigated several inverse algorithms and\nstudied the pros and cons of each. We show a result with a relatively large\nmomentum transfer ($Q^2 \\sim 4\\, {\\rm GeV^2}$) to suppress the elastic\nscattering and reveal the contributions from the resonance and inelastic region\nof the neutrino-nucleon scattering. For elastic scattering, the hadronic tensor\nis the the product of the elastic form factors for the two corresponding\ncurrents. We checked numerically for the case of two charge vector currents\n($V_4$) with the electric form factor calculated from the three-point function\nand found they agree within errors."
    },
    {
        "anchor": "Towards the infrared limit in SU(3) Landau gauge lattice gluodynamics: We study the behavior of the gluon and ghost dressing functions in SU(3)\nLandau gauge at low momenta available on lattice sizes 12^4-32^4 at\n$\\beta$=5.8, 6.0 and 6.2. We demonstrate the ghost dressing function to be\nsystematically dependent on the choice of Gribov copies, while the influence on\nthe gluon dressing function is not resolvable. The running coupling given in\nterms of these functions is found to be decreasing for momenta q<0.6 GeV. We\nstudy also effects of the finite volume and of the lattice discretization.",
        "positive": "Topology changing update algorithms for SU(3) gauge theory: At fine lattice spacings, lattice simulations are plagued by slow\n(topological) modes that give rise to large autocorrelation times. These, in\nturn, lead to statistical and systematic errors that are difficult to estimate.\nWe study the problem and possible algorithmic solutions in 4-dimensional SU(3)\ngauge theory, with special focus on instanton updates and Metadynamics."
    },
    {
        "anchor": "Estimates for the lightest baryon masses in $\\mathcal{N} = 1$\n  supersymmetric Yang-Mills theory: $\\mathcal{N} = 1$ supersymmetric Yang-Mills theory describes gluons\ninteracting with gluinos, which are spin-$\\frac{1}{2}$ Majorana particles in\nthe adjoint representation of the gauge group. In addition to glueballs and\nmesonic bound states, the theory contains color neutral bound states of three\ngluinos, which are analogous to baryons in QCD. We calculate their correlation\nfunctions, involving ``sunset diagrams'' and ``spectacle diagrams'',\nnumerically for gauge group SU(2) and present an update on the estimates for\nthe lowest masses.",
        "positive": "Shear viscosity to relaxation time ratio in SU(3) lattice gauge theory: We evaluate the ratio of the shear viscosity to the relaxation time of the\nshear flux above but near the critical temperature $T_c$ in SU(3) gauge theory\non the lattice. The ratio is related to Kubo's canonical correlation of the\nenergy-momentum tensor in Euclidean space with the relaxation time\napproximation and an appropriate regularization. Using this relation, the ratio\nis evaluated by direct measurements of the Euclidean observables on the\nlattice. We obtained the ratio with reasonable statistics for the range of\ntemperature $1.3T_c \\lesssim T \\lesssim 4T_c$. We also found that the\ncharacteristic speed of the transverse plane wave in gluon media is almost\nconstant, $v \\simeq 0.5$, for $T \\gtrsim 1.5T_c$, which is compatible with the\ncausality in the second order dissipative hydrodynamics."
    },
    {
        "anchor": "Lattice QCD Study for the Interquark Force in Three-Quark and\n  Multi-Quark Systems: We study the three-quark and multi-quark potentials in SU(3) lattice QCD.\n  From the accurate calculation for more than 300 different patterns of 3Q\nsystems, the static ground-state 3Q potential $V_{\\rm 3Q}^{\\rm g.s.}$ is found\nto be well described by the Coulomb plus Y-type linear potential (Y-Ansatz)\nwithin 1%-level deviation. As a clear evidence for Y-Ansatz, Y-type flux-tube\nformation is actually observed on the lattice in maximally-Abelian projected\nQCD. For about 100 patterns of 3Q systems, we perform the accurate calculation\nfor the 1st excited-state 3Q potential $V_{\\rm 3Q}^{\\rm e.s.}$ by diagonalizing\nthe QCD Hamiltonian in the presence of three quarks, and find a large\ngluonic-excitation energy $\\Delta E_{\\rm 3Q} \\equiv V_{\\rm 3Q}^{\\rm\ne.s.}-V_{\\rm 3Q}^{\\rm g.s.}$ of about 1 GeV, which gives a physical reason of\nthe success of the quark model. $\\Delta E_{\\rm 3Q}$ is found to be reproduced\nby the ``inverse Mercedes Ansatz'', which indicates a complicated bulk\nexcitation for the gluonic-excitation mode. We study also the tetra-quark and\nthe penta-quark potentials in lattice QCD, and find that they are well\ndescribed by the OGE Coulomb plus multi-Y type linear potential, which supports\nthe flux-tube picture even for the multi-quarks. Finally, the narrow decay\nwidth of penta-quark baryons is discussed in terms of the QCD string theory.",
        "positive": "Comparison of filtering methods in SU(3) lattice gauge theory: We systematically compare filtering methods used to extract topological\nexcitations from lattice gauge configurations. We show that there is a strong\ncorrelation of the topological charge densities obtained by APE and Stout\nsmearing. Furthermore, a first quantitative analysis of quenched and dynamical\nconfigurations reveals a crucial difference of their topological structure: the\ntopological charge density is more fragmented, when dynamical quarks are\npresent. This fact also implies that smearing has to be handled with great\ncare, not to destroy these characteristic structures."
    },
    {
        "anchor": "The ratio m_c/m_s with Wilson fermions: We determine the quark mass ratio m_c/m_s on the lattice, using Wilson-type\nfermions. Configurations with N_f=2 dynamical clover-improved fermions by the\nQCDSF collaboration are used, which were made available through the ILDG. In\nthe valence sector we use a sophisticated, mass-independently O(a)-improved\nWilson-type action with small cut-off effects even in the charm mass region.\nAfter an extrapolation to the physical pion mass, to zero lattice spacing and\nto infinite box volume, we find m_c/m_s=11.27(30)(26).",
        "positive": "Extracting the rho resonance from lattice QCD simulations at small quark\n  masses: Using established relations between the scattering matrix in infinite volume\nand the two-particle spectrum in a periodic box, we compute the mass and width\nof the rho meson from simulations of N_f=2 flavors of dynamical clover fermions\nat small pion masses 2 m_pi < m_rho."
    },
    {
        "anchor": "Interactions of Charmed Mesons with Light Pseudoscalar Mesons from\n  Lattice QCD and Implications on the Nature of the D_{s0}^*(2317): We study the scattering of light pseudoscalar mesons ($\\pi$, $K$) off charmed\nmesons ($D$, $D_s$) in full lattice QCD. The S-wave scattering lengths are\ncalculated using L\\\"uscher's finite volume technique. We use a relativistic\nformulation for the charm quark. For the light quark, we use domain-wall\nfermions in the valence sector and improved Kogut-Susskind sea quarks. We\ncalculate the scattering lengths of isospin-3/2 $D\\pi$, $D_s\\pi$, $D_sK$,\nisospin-0 $D\\bar{K}$ and isospin-1 $D\\bar{K}$ channels on the lattice. For the\nchiral extrapolation, we use a chiral unitary approach to next-to-leading\norder, which at the same time allows us to give predictions for other channels.\nIt turns out that our results support the interpretation of the\n$D_{s0}^*(2317)$ as a $DK$ molecule. At the same time, we also update a\nprediction for the isospin breaking hadronic decay width\n$\\Gamma(D_{s0}^*(2317)\\to D_s\\pi)$ to $(133\\pm22)$ keV.",
        "positive": "A New Way to Compute the Pseudoscalar Screening Mass at Finite Chemical\n  Potential: We present a method to calculate the pion screening mass in 2+1-flavor\nlattice QCD to $\\mathcal{O}(\\mu^2_\\ell)$, where $\\mu_\\ell$ is the isoscalar\nchemical potential. Our approach is based on the expression for the free theory\npion screening correlator for massless quarks. We use the Taylor expansion\nmethod to calculate the screening correlator to $\\mathcal{O}(\\mu^4_\\ell)$. We\nthen extract the $\\mathcal{O}(\\mu^2_\\ell)$ Taylor coefficient of the screening\nmass from the Taylor coefficients of the correlator, for two temperatures in\nthe range 2 - 3 GeV. Our calculations were done using the Highly Improved\nStaggered Quark action, and the strange and light quark masses were set\nrespectively to their physical and nearly physical values, corresponding to\nmeson masses $M_{\\bar{s}s}=686$ MeV and $M_\\pi=160$ MeV."
    },
    {
        "anchor": "Exotic mesons from quantum chromodynamics with improved gluon and quark\n  actions on the anisotropic lattice: Hybrid (exotic) mesons, which are important predictions of quantum\nchromodynamics (QCD), are states of quarks and anti-quarks bound by excited\ngluons. First principle lattice study of such states would help us understand\nthe role of ``dynamical'' color in low energy QCD and provide valuable\ninformation for experimental search for these new particles. In this paper, we\napply both improved gluon and quark actions to the hybrid mesons, which might\nbe much more efficient than the previous works in reducing lattice spacing\nerror and finite volume effect. Quenched simulations were done at $\\beta=2.6$\nand on a $\\xi=3$ anisotropic $12^3\\times36$ lattice using our PC cluster. We\nobtain $2013 \\pm 26 \\pm 71$ MeV for the mass of the $1^{-+}$ hybrid meson\n${\\bar q}qg$ in the light quark sector, and $4369 \\pm 37 \\pm 99$Mev in the\ncharm quark sector; the mass splitting between the $1^{-+}$ hybrid meson ${\\bar\nc}c g$ in the charm quark sector and the spin averaged S-wave charmonium mass\nis estimated to be $1302 \\pm 37 \\pm 99$ MeV. As a byproduct, we obtain $1438\n\\pm 32 \\pm 57$ MeV for the mass of a P-wave $1^{++}$ ${\\bar u}u$ or ${\\bar d}d$\nmeson and $1499 \\pm 28 \\pm 65$ MeV for the mass of a P-wave $1^{++}$ ${\\bar\ns}s$ meson, which are comparable to their experimental value 1426 MeV for the\n$f_1(1420)$ meson. The first error is statistical, and the second one is\nsystematical. The mixing of the hybrid meson with a four quark state is also\ndiscussed.",
        "positive": "Hadronic decays: Hadronic decays and transitions are a key ingredient of hadronic physics. I\ndiscuss how hadronic decays can be explored in lattice gauge theory and review\nstudies undertaken. I also discuss the impact of decays on masses and how\nlattice studies can explore the nature of a hadronic state: namely whether it\nis a molecular or quark-antiquark state. A brief discussion of lattice\nexploration of pentaquark states is presented."
    },
    {
        "anchor": "Test of factorization for the long-distance effects from charmonium on\n  $B\\to K\\ell^+\\ell^-$: We report on a calculation of the charmonium contribution to the decay $B\n\\rightarrow K\\ell^+\\ell^-$ using lattice simulations with 2+1 flavors of Mobius\ndomain wall fermions. We focus on the region of $q^2$ below the $J/\\psi$\nresonance and test the factorization approximation to estimate the amplitude.\nWe show a possible discrepancy between the lattice calculation and the\nfactorization method for the non-factorizable contribution.",
        "positive": "Nucleon Matrix Elements at Physical Pion Mass and Cost Comparison: We report a lattice calculation of nucleon forward matrix elements on a $48^3\n\\times 96$ lattice at the physical pion mass and a spatial size of 5.5 fm. The\n$2+1$ flavor dynamical fermion configurations are generated with domain-wall\nfermions (DWF) and the overlap fermions are adopted for the valence quarks. The\nisovector $g_A^3$ and $g_S^3$, and the connected insertion part of $g_S^0$ are\nreported for three source-sink separations. With local current, we obtain\n$g_A^3 = 1.18(4)$ from a two-state fit. For the quark momentum fraction\n$\\langle x \\rangle_{u-d}$, we have included smaller lattices (i.e. $24^3 \\times\n64$ and $32^3 \\times 64$ lattice with pion mass at 330 and 290 MeV\nrespectively) for a fit which includes partially quenched cases as well as\nfinite volume and continuum corrections. A global fit with perturbative\nrenormalization gives $\\langle x \\rangle_{u-d} (\\overline{MS},\\, \\mu = 2\\, {\\rm\nGeV}) = 0.170(14)$.\n  We made a cost comparison of calculating the nucleon matrix elements with\nthose from the twisted mass fermion on similar sized lattice at the physical\npion point and the domain-wall fermion calculation on the same DWF lattice. We\nalso compare cost with the clover fermion calculation on similar sized lattice\nat about the same quark mass. The comparison shows that with several\nimprovements, such as many-to-all correlator with grid source and low-mode\nsubstitution in the connected insertion and low-mode average in the quark loop\ncan make the overlap as efficient as the twisted-mass and clover fermions in\ncalculating the three-point functions. It is more efficient than the DWF. When\nthe multi-mass feature is invoked, the overlap can be more efficient in\nreaching the same precision than the single mass comparison made so far."
    },
    {
        "anchor": "Spin Chains and Chiral Lattice Fermions: The generalization of Lorentz invariance to solvable two-dimensional lattice\nfermion models has been formulated in terms of Baxter's corner transfer matrix.\nIn these models, the lattice Hamiltonian and boost operator are given by\nfermionized nearest-neighbor Heisenberg spin chain operators. The\ntransformation properties of the local lattice fermion operators under a boost\nprovide a natural and precise way of generalizing the chiral structure of a\ncontinuum Dirac field to the lattice. The resulting formulation differs from\nboth the Wilson and staggered (Kogut-Susskind) prescriptions. In particular, an\naxial $Q_5$ rotation is sitewise local, while the vector charge rotation mixes\nnearest neighbors on even and odd sublattices.",
        "positive": "Developing and testing the density of states FFA method in the SU(3)\n  spin model: The Density of States Functional Fit Approach (DoS FFA) is a recently\nproposed modern density of states technique suitable for calculations in\nlattice field theories with a complex action problem. In this article we\npresent an exploratory implementation of DoS FFA for the SU(3) spin system at\nfinite chemical potential $\\mu$ - an effective theory for the Polyakov loop.\nThis model has a complex action problem similar to the one of QCD but also\nallows for a dual simulation in terms of worldlines where the complex action\nproblem is solved. Thus we can compare the DoS FFA results to the reference\ndata from the dual simulation and assess the performance of the new approach.\nWe find that the method reproduces the observables from the dual simulation for\na large range of $\\mu$ values, including also phase transitions, illustrating\nthat DoS FFA is an interesting approach for exploring phase diagrams of lattice\nfield theories with a complex action problem."
    },
    {
        "anchor": "Scale invariant behavior in a large N matrix model: Eigenvalue distributions of properly regularized Wilson loop operators are\nused to study the transition from ultra-violet (UV) behavior to infra-red (IR)\nbehavior in gauge theories coupled to matter that potentially have an IR fixed\npoint (FP). We numerically demonstrate emergence of scale invariance in a\nmatrix model that describes $SU(N)$ gauge theory coupled to two flavors of\nmassless adjoint fermions in the large $N$ limit. The eigenvalue distribution\nof Wilson loops of varying sizes cannot be described by a universal lattice\nbeta-function connecting the UV to the IR.",
        "positive": "Properties of the SU(Nc) Gluon Plasma: We investigate the deconfinement transition in SU(Nc) gauge theories, and\nproperties of the deconfined phase. A detailed lattice study of SU(4) and SU(6)\ngauge theories are conducted, and finite volume and cutoff effects on\nthermodynamic observables are studied. The scaling of the deconfinement\ntransition point with lattice spacing is used to calculate the scale,\nLambda_MSbar. The continuum estimates of the thermodynamic quantities are used\nto study properties of the gluon plasma. In particular, the approach to\nconformal limit is studied. We do not find any evidence of a strongly coupled,\nconformal phase in these theories."
    },
    {
        "anchor": "Simulating the scalar field on the fuzzy sphere: The properties of the phi^4 scalar field theory on a fuzzy sphere are studied\nnumerically. The fuzzy sphere is a discretization of the sphere through\nmatrices in which the symmetries of the space are preserved. This model\npresents three different phases: uniform and disordered phases, as in the usual\ncommutative scalar field theory, and a non-uniform ordered phase related to\nUV-IR mixing like non-commutative effects. We have determined the coexistence\nlines between phases, their triple point and their scaling.",
        "positive": "Complex-Temperature Properties of the 2D Ising Model with $\u03b2H = \\pm\n  i \u03c0/2$: We study the complex-temperature properties of a rare example of a\nstatistical mechanical model which is exactly solvable in an external\nsymmetry-breaking field, namely, the Ising model on the square lattice with\n$\\beta H = \\pm i \\pi/2$. This model was solved by Lee and Yang \\cite{ly}. We\nfirst determine the complex-temperature phases and their boundaries. From a\nlow-temperature, high-field series expansion of the partition function, we\nextract the low-temperature series for the susceptibility $\\chi$ to\n$O(u^{23})$, where $u=e^{-4K}$. Analysing this series, we conclude that $\\chi$\nhas divergent singularities (i) at $u=u_e=-(3-2^{3/2})$ with exponent\n$\\gamma_e'=5/4$, (ii) at $u=1$, with exponent $\\gamma_1'=5/2$, and (iii) at\n$u=u_s=-1$, with exponent $\\gamma_s'=1$. We also extract a shorter series for\nthe staggered susceptibility and investigate its singularities. Using the exact\nresult of Lee and Yang for the free energy, we calculate the specific heat and\ndetermine its complex-temperature singularities. We also carry this out for the\nuniform and staggered magnetisation."
    },
    {
        "anchor": "Baryon masses at O(a^2) in chiral perturbation theory: The chiral Lagrangian for the Symanzik action through O(a^2) for baryons is\nobtained. We consider two flavor unquenched and partially quenched lattice\ntheories, allowing for mixed actions in the latter. As an application, we\ncalculate masses to O(a^2) for the nucleons and deltas, and investigate the\ncorrections due to the violation of O(4) rotational invariance. These results\nare contrasted with those in the meson sector for lattice simulations using\nmixed and unmixed actions of Wilson and Ginsparg-Wilson quarks.",
        "positive": "On Lattice QCD with Many Flavors: We discuss the confining and chiral-symmetry breaking properties of QCD with\na large number of flavors $N_f$. In a Monte Carlo simulation of QCD with $N_f\n=16$ staggered fermions, we find clear evidence of a first order bulk phase\ntransition which separates phases with broken and unbroken chiral symmetry.\nThis is consistent with extrapolations of earlier studies with smaller $N_f$,\nand is also as expected from general arguments. Thus, even when the\nperturbative renormalization group flow has a new infrared stable fixed point\nnear the origin, lattice artifacts induce chiral symmetry breaking, and\npresumably confinement, at sufficiently strong coupling."
    },
    {
        "anchor": "Lattice determination of the critical point of QCD at finite T and \u03bc: Based on universal arguments it is believed that there is a critical point\n(E) in QCD on the temperature (T) versus chemical potential (\\mu) plane, which\nis of extreme importance for heavy-ion experiments. Using finite size scaling\nand a recently proposed lattice method to study QCD at finite \\mu we determine\nthe location of E in QCD with n_f=2+1 dynamical staggered quarks with\nsemi-realistic masses on $L_t=4$ lattices. Our result is T_E=160 \\pm 3.5 MeV\nand \\mu_E= 725 \\pm 35 MeV. For the critical temperature at \\mu=0 we obtained\nT_c=172 \\pm 3 MeV.",
        "positive": "The Shape of the Renormalized Trajectory in the Two-dimensional O(N)\n  Non-linear Sigma Model: The renormalized trajectory in the multi-dimensional coupling parameter space\nof the two-dimensional O(3) non-linear sigma model is determined numerically\nunder \\linebreak $\\delta$-function block spin transformations using two\ndifferent Monte Carlo renormalization group techniques. The renormalized\ntrajectory is compared with the straight line of the fixed point trajectory\n(fixed point action) which leaves the asymptotically free ultraviolet fixed\npoint of the critical surface in the orthogonal direction. Our results show\nthat the renormalized trajectory breaks away from the fixed point trajectory in\na range of the correlation length around $\\xi \\approx 3$-$7$, flowing into the\nhigh temperature fixed point at $\\xi=0$. The analytic large $N$ calculation of\nthe renormalized trajectory is also presented in the coupling parameter space\nof the most general bilinear Hamiltonians. The renormalized trajectory in the\nlarge $N$ approximation exhibits a similar shape as in the $N=3$ case, with the\nsharp break occurring at a smaller correlation length of $\\xi \\approx 2$-$3$."
    },
    {
        "anchor": "QCD confinement and chiral crossovers, two critical points: We study the QCD phase diagram, in particular we study the critical points of\nthe two main QCD phase transitions, confinement and chiral symmetry breaking.\nConfinement drives chiral symmetry breaking, and, due to the finite quark mass,\nat small density both transitions are a crossover, while they are a first or\nsecond order phase transition in large density. We study the QCD phase diagram\nwith a quark potential model including both confinement and chiral symmetry. We\npresent the confinement of quark fields into a flux tube, obtained in SU(3)\nquenched lattice QCD, to illustrate the importance of the confining\nquark-antiquark potential. Our finite temperature con-fining potential is\nextracted from the Lattice QCD data of the Bielefeld group. Our formalism, the\nCoulomb gauge hamiltonian of QCD, is presently the only one able to\nmicroscopically include both a quark-antiquark confining potential and a vacuum\ncondensate of quark-antiquark pairs. This model is able to address all the\nexcited hadrons, and chiral symmetry breaking, at the same token. Our order\nparameters are the Polyakov loop and the quark mass gap. We address how the\nquark masses affect the critical point location in the phase diagram.",
        "positive": "Diffusion of topological charge in lattice QCD simulations: We study the autocorrelations of observables constructed from the topological\ncharge density, such as the topological charge on a time slice or in a\nsubvolume, using a series of hybrid Monte Carlo simulations of pure SU(3) gauge\ntheory with both periodic and open boundary conditions. We show that the\nautocorrelation functions of these observables obey a simple diffusion equation\nand we measure the diffusion coefficient, finding that it scales like the\nsquare of the lattice spacing. We use this result and measurements of the rate\nof tunneling between topological charge sectors to calculate the scaling\nbehavior of the autocorrelation times of these observables on periodic and open\nlattices. There is a characteristic lattice spacing at which open boundary\nconditions become worthwhile for reducing autocorrelations and we show how this\nlattice spacing is related to the diffusion coefficient, the tunneling rate,\nand the lattice Euclidean time extent."
    },
    {
        "anchor": "Lattice QCD at nonzero temperature and density: In this talk I review the current status of lattice QCD calculations at\nnonzero temperature and density. I focus on the QCD phase structure and bulk\nQCD thermodynamics at zero and nonzero chemical potentials.",
        "positive": "The large N limit of SU(N) integrals in lattice models: The standard U(N) and SU(N) integrals are calculated in the large N limit.\nOur main finding is that for an important class of integrals this limit is\ndifferent for two groups. We describe the critical behaviour of SU(N) models\nand discuss implications of our results for the large N behaviour of SU(N)\nlattice gauge theories at finite temperatures and non-zero baryon chemical\npotential. The key ingredients of our approach are 1) expansion of the\nintegrals into a sum over irreducible representations and 2) calculation of\nsums over partitions of r of products of dimensions of two different\nrepresentations of a symmetric group $S_r$."
    },
    {
        "anchor": "Baryons in the plasma: in-medium effects and parity doubling: We investigate the fate of baryons made out of u, d and s quarks in the\nhadronic gas and the quark-gluon plasma, using nonperturbative lattice\nsimulations, employing the FASTSUM anisotropic Nf=2+1 ensembles. In the\nconfined phase a strong temperature dependence is seen in the masses of the\nnegative-parity groundstates, while the positive-parity groundstate masses are\napproximately temperature independent, within the error. At high temperature\nparity doubling emerges. A noticeable effect of the heavier s quark is seen. We\ngive a simple description of the medium-dependent masses for the\nnegative-parity states and speculate on the relevance for heavy-ion\nphenomenology via the hadron resonance gas.",
        "positive": "Finite volume effects on the electric polarizability of neutral hadrons\n  in lattice QCD: We study the finite volume effects on the electric polarizability for the\nneutron, neutral pion, and neutral kaon using eight dynamically generated\ntwo-flavor nHYP-clover ensembles at two different pion masses: 306(1) and\n227(2) MeV. An infinite volume extrapolation is performed for each hadron at\nboth pion masses. For the neutral kaon, finite volume effects are relatively\nmild. The dependence on the quark mass is also mild and a reliable chiral\nextrapolation can be performed along with the infinite volume extrapolation.\nOur result is $\\alpha_{K^0}^\\mbox{phys}=0.356(74) \\times 10^{-4} \\mbox{fm}^3$.\nIn contrast, for neutron the electric polarizability depends strongly on the\nvolume. After removing the finite volume corrections, our neutron\npolarizability results are in good agreement with $\\chi$PT. For the connected\npart of the neutral pion polarizability, the negative trend persists, and it is\nnot due to finite volume effects, but likely sea quark charging effects."
    },
    {
        "anchor": "B meson decays from moving-NRQCD on fine MILC lattices: Lattice simulations of $B\\to\\pi l\\nu$ decays are problematic in the low\n$q^{2}$ region when the pion has to have large momentum in the lattice frame\nfor a $B$ meson at rest or moving slowly. The moving-NRQCD formalism provides a\nway around this by giving an accurate discretization of a $b$ quark moving at\narbitrary velocity $v$, and therefore a $B$ meson moving at high momentum in\nthe lattice frame. Here we show results from simulations of the moving-NRQCD\naction complete through $O(1/M)$ coupled to the asqtad action on a MILC fine\nensemble. We show $B$, $B^{*}$ masses as a function of $v$ and demonstrate how\nto determine the meson kinetic mass and the renormalization of $v$\nnon-perturbatively. We will also discuss the perturbative renormalization of\nthe moving-NRQCD action from high-$\\beta$ Monte Carlo simulations.",
        "positive": "Four-dimensional domain decomposition for the factorization of the\n  fermion determinant: The non-local dependence of the fermion determinant on the gauge field limits\nour ability of simulating Quantum Chromodynamics on the lattice. Here we\npresent a factorization of the gauge field dependence of the fermion\ndeterminant based on an overlapping four-dimensional domain decomposition of\nthe lattice. The resulting action is block-local in the gauge and in the\nauxiliary bosonic fields. Possible applications are multi-level integration,\nmaster field simulations, and more efficient parallelizations of Monte Carlo\nalgorithms and codes."
    },
    {
        "anchor": "Vector and scalar charmonium resonances with lattice QCD: We perform an exploratory lattice QCD simulation of $D \\bar D$ scattering,\naimed at determining the masses as well as the decay widths of charmonium\nresonances above open charm threshold. Neglecting coupling to other channels,\nthe resulting phase shift for $D \\bar D$ scattering in p-wave yields the\nwell-known vector resonance $\\psi(3770)$. For $m_\\pi = 156$ MeV, the extracted\nresonance mass and the decay width agree with experiment within large\nstatistical uncertainty. The scalar charmonium resonances present a puzzle,\nsince only the ground state $\\chi_{c0}(1P)$ is well understood, while there is\nno commonly accepted candidate for its first excitation. We simulate $D \\bar D$\nscattering in s-wave in order to shed light on this puzzle. The resulting phase\nshift supports the existence of a yet-unobserved narrow resonance with a mass\nslightly below 4 GeV. A scenario with this narrow resonance and a pole at\n$\\chi_{c0}(1P)$ agrees with the energy-dependence of our phase shift. Further\nlattice QCD simulations and experimental efforts are needed to resolve the\npuzzle of the excited scalar charmonia.",
        "positive": "Thermodynamics of lattice QCD with 3 flavours of colour-sextet quarks: We have been studying QCD with 2 flavours of colour-sextet quarks to\ndistinguish whether it is QCD-like or conformal. For comparison we are now\nstudying QCD with 3 flavours of colour-sextet quarks, which is believed to be\nconformal in the chiral limit. Here we present the results of simulations of\nlattice QCD with 3 colour-sextet quarks at finite temperatures on lattices of\ntemporal extent $N_t=4$ and 6, with masses small enough to yield access to the\nchiral limit. As for the 2-flavour case, we find well-separated deconfinement\nand chiral-symmetry restoration transitions, both of which move to appreciably\nweaker couplings as $N_t$ is increased from 4 to 6. If this theory is\nconformal, we would expect there to be a bulk chiral transition at a fixed\ncoupling. For this reason we conclude that for $N_t=4$ and 6, the chiral and\nhence the deconfinement transitions are in the strong-coupling domain where the\ntheory is essentially quenched. The similarity between the behaviours of the 2\nand 3 flavour theories suggested that the $N_t=4$ and 6 transitions for the\n2-flavour theory also lie in the strong-coupling domain. The phase structure of\nboth theories is very similar."
    },
    {
        "anchor": "Dynamical fermions in lattice quantum chromodynamics: The thesis will present results in Quantum Chromo Dynamics (QCD) with\ndynamical lattice fermions. The topological susceptibilty in QCD is determined,\nthe calculations are carried out with dynamical overlap fermions. The most\nimportant properties of the quark-gluon plasma phase of QCD are studied, for\nwhich dynamical staggered fermions are used.",
        "positive": "Status of the Lambda Lattice Scale for the SU(3) Wilson gauge action: With the emergence of the Yang-Mills gradient flow technique there is renewed\ninterest in the issue of scale setting in lattice gauge theory. Here I compare\nfor the SU(3) Wilson gauge action non-perturbative scale functions of Edwards,\nHeller and Klassen (EHK), Necco and Sommer (NS), both relying on Sommer's\nmethod using the quark potential, and the scale function derived by Bazavov,\nBerg and Velytsky (BBV) from a deconfining phase transition investigation by\nthe Bielefeld group. It turns out that the scale functions are based on\nmutually inconsistent data, though the BBV scale function is consistent with\nthe EHK data when their low $\\beta$ ($\\beta=5.6$) data point is removed.\nBesides, only the BBV scale function is consistent with three data points\ncalculated from the gradient flow by L\\\"uscher. In the range for which data\nexist the discrepancies between the scale functions are only up to $\\pm 2$\\% of\ntheir values, but clearly visible within the statistical accuracy."
    },
    {
        "anchor": "Overlap fermion with the topology conserving gauge action: We investigate the distribution of low-lying eigenmodes of hermitian\nWilson-Dirac operator, $H_W$, with the gauge action whose form is designed to\navoid topology change, as well as with the standard plaquette action. On the\nquenched lattices, the former gauge action exhibits less density of low-lying\neigenmodes of $H_W$ compared to the latter at the same lattice spacing. We also\nshow preliminary results for the dynamical simulation with two flavors of\noverlap fermions.",
        "positive": "Twisted supersymmetric sigma model on the lattice: In this paper we conduct a numerical study of the supersymmetric O(3)\nnon-linear sigma model. The lattice formulation we employ was derived in\n\\cite{sigma1} and corresponds to a discretization of a {\\it twisted} form of\nthe continuum action. The twisting process exposes a {\\it nilpotent}\nsupercharge $Q$ and allows the action to be rewritten in $Q$-exact form. These\nproperties may be maintained on the lattice. We show how to deform the theory\nby the addition of potential terms which preserve the supersymmetry. A Wilson\nmass operator may be introduced in this way with a minimal breaking of\nsupersymmetry. We additionally show how to rewrite the theory in the language\nof K\\\"{a}hler-Dirac fields and explain why this avenue does not provide a good\nroute to discretization. Our numerical results provide strong evidence for a\nrestoration of full supersymmetry in the continuum limit {\\it without} fine\ntuning. We also observe a non-vanishing chiral condensate as expected from\ncontinuum instanton calculations."
    },
    {
        "anchor": "The Static Potential to O(\u03b1^2) in Lattice Perturbation Theory: We present a calculation of Wilson loops, and the static inter-quark\npotential to $O(\\alpha^2)$ in lattice perturbation theory. This is carried out\nwith the Wilson, Symanzik-Weisz, and Iwasaki gauge actions and the Wilson,\nSheikholeslami-Wohlert, and Kogut-Susskind dynamical fermion action for small\nWilson loops, and with the Wilson gauge action and each of the dynamical quark\nactions in the case of the static potential.",
        "positive": "The Coulomb flux tube revisited: We perform $SU(2)$ Yang-Mills lattice simulation of the electric field\ndistribution in the Coulomb gauge for different values of $\\beta$ to further\ninvestigate the nature of the Coulomb flux tube."
    },
    {
        "anchor": "The hadronic running of the electromagnetic coupling and electroweak\n  mixing angle: We present results for the hadronic running of the electromagnetic coupling\nand the weak mixing angle from simulations of lattice QCD with $N_f=2+1$\nflavours of $O(a)$-improved Wilson fermions. Using two different\ndiscretisations of the vector current, we compute the quark-connected and\n-disconnected contributions to the hadronic vacuum polarisation (HVP) functions\n$\\bar{\\Pi}^{\\gamma\\gamma}$ and $\\bar{\\Pi}^{Z\\gamma}$ for spacelike squared\nmomenta $Q^2\\leq 7$ $\\mathrm{GeV}^2$. Our results are extrapolated to the\nphysical point using ensembles at four lattice spacings, with pion masses\nranging from 130 to 420 MeV. We observe a tension of up to 3.5 standard\ndeviations between our lattice results for $\\Delta\\alpha_{\\rm had}^{(5)}(-Q^2)$\nand estimates based on the $\\textit{R}$-ratio for space-like momenta in the\nrange $Q^2=3-7\\,\\rm GeV^2$. To obtain an estimate for\n$\\Delta\\alpha_\\mathrm{had}^{(5)}(M_Z^2)$, we employ the Euclidean split\ntechnique. The implications for comparison with global electroweak fits are\nassessed.",
        "positive": "Nucleon sigma term and strange quark content in 2+1-flavor QCD with\n  dynamical overlap fermions: We study the sigma term and the strange quark content of nucleon in\n2+1-flavor QCD with dynamical overlap fermions. We analyze the lattice data of\nnucleon mass taken at two different strange quark masses with five values of up\nand down quark masses each. Using the reweighting technique, we study the\nstrange quark mass dependence of the nucleon and extract the strange quark\ncontent."
    },
    {
        "anchor": "Relationship between various supersymmetric lattice models: We comment on the relationships between several supersymmetric lattice\nmodels; the ``orbifold lattice theory'' by Cohen-Kaplan-Katz-Unsal (CKKU),\nlattice regularization of the topological field theory by Sugino and the\n``geometrical approach'' by Catterall. We point out that these three models\nhave close relationships; the N =(2,2) model by Catterall [Catterall] and the\ntwo-dimensional N = (2,2) lattice theory being similar to Sugino's construction\n[Sugino] can be derived by appropriate truncation of fields in the\ntwo-dimensional N = (4,4) orbifold lattice theory by CKKU [Cohen et al].\nCatterall's N = (2,2) description possesses extra degrees of freedom compared\nto the target N = (2,2) theory. If we remove those extra degrees of freedom in\na way keeping supersymmetry on the lattice, Catterall's description reduces to\na model of the Sugino type.",
        "positive": "The (dual) Meissner effect in SU(2) and SU(3) QCD: After making an abelian projection in the maximally abelian gauge, we measure\nthe distribution of abelian electric flux and monopole currents around an\nabelian Wilson loop in $SU(2)$ and $SU(3)$ QCD. The (dual) Meissner effect is\nobserved clearly. The vacua in the confinement phases of $SU(2)$ and $SU(3)$\nare both at around the border between type-1 and type-2 (dual) superconductor."
    },
    {
        "anchor": "Quenched Lattice Results for $f_B$ and $f_D$: We have computed the decay constants for the $B$ and $D$ mesons, using\nquenched lattices at $\\beta=6.3$, by interpolating between the static\napproximation of Eichten and the conventional (``heavy'' Wilson fermion)\nmethod. A more careful treatment of the static result using better sources with\nlonger time-displacements and a modification to the Wilson quark normalization\nto correct approximately for lattice effects in the large-$am$ regime have led\nto the elimination of the large discrepancy between the two methods which had\nbeen previously observed. We report final results, with estimates of various\nsystematic errors.",
        "positive": "The equivalence of the SU(N) Yang Mills Theory with a Purely Fermionic\n  Model: We investigate the detailed conditions under which a purely fermionic model\nwith current-current interaction goes over to a renormalizable, asymptotically\nfree SU$(N)$ gauge theory."
    },
    {
        "anchor": "The nature of the Roberge-Weiss transition in $N_f=2$ QCD with Wilson\n  fermions: At imaginary values of the quark chemical potential $\\mu$, Quantum\nChromodynamics shows an interesting phase structure due to an exact center, or\nRoberge-Weiss (RW), symmetry. This can be used to constrain QCD at real $\\mu$,\nwhere the sign problem prevents Monte Carlo simulations of the lattice theory.\nIn previous studies of this region with staggered fermions it was found that\nthe RW endpoint, where the center transition changes from first-order to a\ncrossover, depends non-trivially on the quark mass: for high and low masses, it\nis a triple point connecting to the deconfinement and chiral transitions,\nrespectively, changing to a second-order endpoint for intermediate mass values.\nThese parameter regions are separated by tricritical points. Here we present a\nconfirmation of these findings using Wilson fermions on $N_\\tau=4$ lattices. In\naddition, our results provide a successful quantitative check for a heavy quark\neffective lattice theory at finite density.",
        "positive": "Parallel tempering algorithm applied to the deconfinement transition of\n  quenched QCD: QCD with infinite heavy quark masses exhibits a first-order thermal\ntransition which is driven by the spontaneous breaking of the global\n$\\mathcal{Z}_3$ center symmetry. We analyze the corresponding order parameter,\nnamely the Polyakov loop and its moments, and show, with a rigorous finite size\nscaling, that in the continuum limit the transition is of first order. We show\nthat the use of a parallel tempering algorithm can significantly reduce the\nlarge auto-correlation times which are mainly caused by the supercritical\nslowing down. As a result, we calculate the transition temperature $w_0 T_c$\nwith per-mill precision, and the latent heat, carrying out controlled continuum\nand infinite volume extrapolations."
    },
    {
        "anchor": "Finite Temperature QCD Interfaces Out of Equilibrium: The properties of interfaces in non-equilibrium situations are studied by\nconstructing a density matrix with a space-dependent temperature. The\ntemperature gradient gives rise to new terms in the equation for the order\nparameter. Surface terms induced in effective actions by abrupt temperature\nchanges provide a natural theoretical framework for understanding the occurence\nof both continuous and discontinuous behavior in the order parameter. Monte\nCarlo simulation of pure QCD shows both kinds of interfacial behavior.\nPerturbation theory predicts a universal profile in the high temperature phase,\nwhich can be tested by Monte Carlo simulation.",
        "positive": "Confinement in SU(3: Simple and Generalized Maximal Abelian Gauge: The general problem of obtaining reliable results from gauge-fixing and\nprojection is discussed. It is shown that the usual form of the maximal abelian\ngauge gives poor results for the string tension in SU(3) lattice gauge theory.\nA generalized form is suggested. Evidence is presented that monopoles in SU(3)\nare associated with SU(2) subgroups, and that P-vortices pass through\nmonopoles, similar to what happens in SU(2)."
    },
    {
        "anchor": "Lattice QCD computation of the SU(3) String Tension critical curve: We investigate the critical curve of the string tension sigma(T) as a\nfunction of temperature in quenched gauge invariant SU(3) lattice gauge theory.\nWe extract sigma(T) from the colour averaged free energy of a static\nquark-antiquark pair. To compute the free energy, we utilize a pair of gauge\ninvariant Polyakov loop and antiloop correlations, and apply the multihit\nprocedure to enhance the signal to noise ratio. We find that the string tension\ndeparts from the zero temperature sigma(0) at T close to 0.5 Tc. We cover the\nrelevant temperature range from 0.5 Tc up to the confinement temperature Tc\nusing 57 different sets of pure gauge lattice configurations with four temporal\nextensions (4,6,8,12), different beta and a spatial volume of 48^3 in lattice\nunits.",
        "positive": "Charmonium spectroscopy with optimal distillation profiles: We use the method of optimal distillation profiles to compute the low-lying\ncharmonium spectrum in an $N_f = 3+1$ ensemble at the $SU(3)$ light flavor\nsymmetric point ($m_{\\pi} \\approx 420$ MeV), physical charm quark mass and\nlattice spacing $a\\approx 0.0429$ fm. The spectrum and mass splittings display\ngood agreement with their values in nature and the statistical errors are\ncomparable, if not smaller, than those of state-of-the-art lattice\ncalculations. We also present first results on the mixing of charmonium with\nglueballs and light hadrons obtained in a similar $N_f = 3+1$ ensemble but at\nlarger pion mass."
    },
    {
        "anchor": "Phase Shift with LapH Propagators: The pion-pion scattering phase shift is computed using LapH propagators. The\nLapH method for computing quark propagators is used to form two-particle\ncorrelation functions with a number of different operators. Excited state\nenergies of two-particle states on 2+1 dynamical, anisotropic lattices (Mpi=390\nMeV) are computed to determine the phase shift in the isospin-2 channel. The\nsignal for t-to-t diagrams for the isospin-0 channel are also presented to\ndemonstrate the efficacy of the stochastic LapH method which combines LapH with\ndiluted Z4 noise sources.",
        "positive": "Super-heavy Quarkonia as a probe of the QCD Vacuum: We investigate the effect of a non-perturbative gluon condensate on the\nspectrum of bound states of extremely heavy quarks using Non-Relativistic-QCD\n(NRQCD). Simulations are done with an improved gluon action on small lattices.\nWe compare our numerical results with perturbative calculations to test the\nconsistency."
    },
    {
        "anchor": "Long distance part of $\u03b5_K$ from lattice QCD: We demonstrate the lattice QCD calculation of the long distance contribution\nto $\\epsilon_K$. Due to the singular, short-distance structure of $\\epsilon_K$,\nwe must perform a short-distance subtraction and introduce a corresponding\nlow-energy constant determined from perturbation theory, which we calculate at\nNext Leading Order (NLO). We perform the calculation on a $24^3 \\times 64$\nlattice with a pion mass of 329 MeV. This work is a complete calculation, which\nincludes all connected and disconnected diagrams.",
        "positive": "Nucleon Electromagnetic Form Factors from Lattice QCD using 2+1 Flavor\n  Domain Wall Fermions on Fine Lattices and Chiral Perturbation Theory: We present a high-statistics calculation of nucleon electromagnetic form\nfactors in $N_f=2+1$ lattice QCD using domain wall quarks on fine lattices, to\nattain a new level of precision in systematic and statistical errors. Our\ncalculations use $32^3 \\times 64$ lattices with lattice spacing a=0.084 fm for\npion masses of 297, 355, and 403 MeV, and we perform an overdetermined analysis\nusing on the order of 3600 to 7000 measurements to calculate nucleon electric\nand magnetic form factors up to $Q^2 \\approx$ 1.05 GeV$^2$. Results are shown\nto be consistent with those obtained using valence domain wall quarks with\nimproved staggered sea quarks, and using coarse domain wall lattices. We\ndetermine the isovector Dirac radius $r_1^v$, Pauli radius $r_2^v$ and\nanomalous magnetic moment $\\kappa_v$. We also determine connected contributions\nto the corresponding isoscalar observables. We extrapolate these observables to\nthe physical pion mass using two different formulations of two-flavor chiral\neffective field theory at one loop: the heavy baryon Small Scale Expansion\n(SSE) and covariant baryon chiral perturbation theory. The isovector results\nand the connected contributions to the isoscalar results are compared with\nexperiment, and the need for calculations at smaller pion masses is discussed."
    },
    {
        "anchor": "Understanding localisation in QCD through an Ising-Anderson model: Above the QCD chiral crossover temperature, the low-lying eigenmodes of the\nDirac operator are localised, while moving up in the spectrum states become\nextended. This localisation/delocalisation transition has been shown to be a\ngenuine second-order phase transition, in the same universality class as that\nof the 3D Anderson model. The existence of localised modes and the effective\ndimensional reduction can be tentatively explained as a consequence of local\nfluctuations of the Polyakov loop, that provide 3D on-site disorder, in analogy\nto the on-site disorder of the Anderson model. To test the viability of this\nexplanation we study a 3D effective, Anderson-like model, with on-site disorder\nprovided by the spins of a spin model, which mimics the Polyakov loop dynamics.\nOur preliminary results show that localised modes are present in the ordered\nphase, thus supporting the proposed mechanism for localisation in QCD.",
        "positive": "Two Nucleon Systems at $m_\u03c0\\sim 450~{\\rm MeV}$ from Lattice QCD: Nucleon-nucleon systems are studied with lattice quantum chromodynamics at a\npion mass of $m_\\pi\\sim 450~{\\rm MeV}$ in three spatial volumes using $n_f=2+1$\nflavors of light quarks. At the quark masses employed in this work, the\ndeuteron binding energy is calculated to be $B_d = 14.4^{+3.2}_{-2.6} ~{\\rm\nMeV}$, while the dineutron is bound by $B_{nn} = 12.5^{+3.0}_{-5.0}~{\\rm MeV}$.\nOver the range of energies that are studied, the S-wave scattering phase shifts\ncalculated in the 1S0 and 3S1-3D1 channels are found to be similar to those in\nnature, and indicate repulsive short-range components of the interactions,\nconsistent with phenomenological nucleon-nucleon interactions. In both\nchannels, the phase shifts are determined at three energies that lie within the\nradius of convergence of the effective range expansion, allowing for\nconstraints to be placed on the inverse scattering lengths and effective\nranges. The extracted phase shifts allow for matching to nuclear effective\nfield theories, from which low energy counterterms are extracted and issues of\nconvergence are investigated. As part of the analysis, a detailed investigation\nof the single hadron sector is performed, enabling a precise determination of\nthe violation of the Gell-Mann--Okubo mass relation. [An Erratum to the\npublished version is included as an appendix. It details the impact of an error\ndiscovered in 2020 and corrects typographical errors.]"
    },
    {
        "anchor": "$u d \\bar{b} \\bar{b}$ tetraquark resonances with lattice QCD potentials\n  and the Born-Oppenheimer approximation: We study tetraquark resonances with lattice QCD potentials computed for a\nstatic bbar bbar pair in the presence of two lighter quarks u d, the\nBorn-Oppenheimer approximation and the emergent wave method. As a proof of\nconcept we focus on the system with isospin I = 0, but consider different\nrelative angular momenta l of the heavy quarks bbar bbar. For l=0 a bound state\nhas already been predicted with quantum numbers I(JP) = 0(1+). Exploring\nvarious angular momenta we now compute the phase shifts and search for S and T\nmatrix poles in the second Riemann sheet. We predict a tetraquark resonance for\nl =1, decaying into two B mesons, with quantum numbers I(JP) = 0(1-), mass m =\n10 \\, 576^{+4}_{-4} MeV} and decay width Gamma = 112^{+90}_{-103} MeV.",
        "positive": "Cyclic Leibniz rule: a formulation of supersymmetry on lattice: For the purpose of constructing supersymmetric(SUSY) theories on lattice, we\npropose a new type relation on lattice -cyclic Leibniz rule(CLR)- which is\nslightly different from an ordinary Leibniz rule. Actually, we find that CLR\ncan enlarge the number of SUSYs and construct more Nicolai mappings in a\nquantum-mechanical model. In this model, the exact mass degeneracy between\nfermion and boson is shown."
    },
    {
        "anchor": "A New Formulation in Lattice Theory: In this paper we propose a new approach to formulate the field theory on a\nlattice. This approach can eliminate the Fermion doubling problem, preserve the\nchiral symmetry and get the same dispersion relation for both Fermion and Boson\nfields. This gives us the possibility to write down the chiral model (such as\nthe Weinberg-Salam model) on a lattice.",
        "positive": "Flux tubes at Finite Temperature: We show the flux tubes produced by static quark-antiquark, quark-quark and\nquark-gluon charges at finite temperature. The sources are placed in the\nlattice with fundamental and adjoint Polyakov loops. We compute the square\ndensities of the chromomagnetic and chromoelectric fields above and below the\nphase transition. Our results are gauge invariant and produced in pure gauge\nSU(3). The codes are written in CUDA and the computations are performed with\nGPUs."
    },
    {
        "anchor": "Towards the understanding of $Z_c(3900)$ from lattice QCD: Within the framework of three-channel Ross-Shaw effective range theory, we\nderive the constraints among different parameters of the theory in the case of\na narrow resonance close to the threshold of the third channel, which is\nrelevant for the resonance-like structure $Z_c(3900)$. The usage of these\nconstraint relations, together with the multi-channel L\\\"uscher formula in\nlattice QCD calculations are also discussed and the strategies are outlined.",
        "positive": "Simplicial Quantum Gravity on a Randomly Triangulated Sphere: We study 2D quantum gravity on spherical topologies employing the Regge\ncalculus approach with the dl/l measure. Instead of the normally used fixed\nnon-regular triangulation we study random triangulations which are generated by\nthe standard Voronoi-Delaunay procedure. For each system size we average the\nresults over four different realizations of the random lattices. We compare\nboth types of triangulations quantitatively and investigate how the difference\nin the expectation value of the squared curvature, $R^2$, for fixed and random\ntriangulations depends on the lattice size and the surface area A. We try to\nmeasure the string susceptibility exponents through finite-size scaling\nanalyses of the expectation value of an added $R^2$-interaction term, using two\nconceptually quite different procedures. The approach, where an ultraviolet\ncut-off is held fixed in the scaling limit, is found to be plagued with\ninconsistencies, as has already previously been pointed out by us. In a\nconceptually different approach, where the area A is held fixed, these problems\nare not present. We find the string susceptibility exponent $\\gamma_{str}'$ in\nrough agreement with theoretical predictions for the sphere, whereas the\nestimate for $\\gamma_{str}$ appears to be too negative. However, our results\nare hampered by the presence of severe finite-size corrections to scaling,\nwhich lead to systematic uncertainties well above our statistical errors. We\nfeel that the present methods of estimating the string susceptibilities by\nfinite-size scaling studies are not accurate enough to serve as testing grounds\nto decide about a success or failure of quantum Regge calculus."
    },
    {
        "anchor": "Asymptotics of the Infrared: We follow recent formulations of dimensionally reduced loop operators for\nquantum field theories and exact representations of probabilistic lattice\ndynamics to identify a new scheme for the evaluation of partition function\nzeroes, allowing for the explicit analysis of quantum critical phenomena. This\nnew approach gives partition function zeroes from a factored quantum loop\noperator basis and, as we show, constitutes an effective mapping of the\nrenormalization group $\\beta$-function onto the noncommuting local operator\nbasis of a countably finite Hilbert space. The Vafa-Witten theorem for\nCP-violation and related complex action problems of Euclidean Field theories\nare discussed, following recent treatments, and are shown to be natural\nconsequences of the analyticity of the limiting distribution of these zeroes,\nand properties of vacuum regimes governed by a dominant quantum fluctuation in\nthe vicinity of a renormalization group equation fixed point in the infrared.",
        "positive": "Calculation of Nucleon Electromagnetic Form Factors: The fomalism is developed to express nucleon matrix elements of the\nelectromagnetic current in terms of form factors consistent with the\ntranslational, rotational, and parity symmetries of a cubic lattice. We\ncalculate the number of these form factors and show how appropriate linear\ncombinations approach the continuum limit."
    },
    {
        "anchor": "Localization of Dirac modes in the $\\mathrm{SU}(2)$ Higgs model at\n  finite temperature: We investigate the connection between localization of low-lying Dirac modes\nand Polyakov-loop ordering in the lattice $\\mathrm{SU}(2)$ Higgs model at\nfinite temperature, probed with the staggered Dirac operator. After mapping out\nthe phase diagram of the model at a fixed temporal extension in lattice units,\nwe study the localization properties of the low-lying modes of the staggered\nDirac operator, how these properties change across the various transitions, and\nhow these modes correlate with the gauge and Higgs fields. We find localized\nlow modes in the deconfined and in the Higgs phase, where the Polyakov loop is\nstrongly ordered, but in both cases they disappear as one crosses over to the\nconfined phase. Our findings confirm the general expectations of the\n\"sea/islands\" picture, and the more detailed expectations of its refined\nversion concerning the favorable locations of localized modes, also in the\npresence of dynamical scalar matter.",
        "positive": "Semi-leptonic Decays of Heavy Flavours on a Fine Grained Lattice: We present the results of a numerical calculation of semi-leptonic form\nfactors relevant for heavy flavour meson decays into light mesons, at\n$\\beta=6.4$ on a $24^3 \\times 60$ lattice, using the Wilson action in the\nquenched approximation. We obtain $f^+_K(0)=0.65\\pm 0.18$, $V(0)=0.95\\pm 0.34$,\n$A_1(0)=0.63\\pm 0.14 $ and $A_2(0)=0.45\\pm 0.33 $. We also obtain\n$A_1(q^2_{max})=0.62\\pm 0.09$, $V(0)/A_1(0)=1.5\\pm 0.28 $ and\n$A_2(0)/A_1(0)=0.7\\pm 0.4$. The results for $f^+_K(0)$, $V(0)$ and $A_1(0)$ are\nconsistent with the experimental data and with previous lattice determinations\nwith larger lattice spacings. In the case of $A_2(0)$ the errors are too large\nto draw any firm conclusion. We have also extrapolated the form factors to the\nB meson, showing a behaviour compatible with the predictions by the heavy quark\neffective theory (HQET). Within large uncertainties, our results suggest that\n$A_2/A_1$ increases with the heavy quark mass. We also get very rough estimates\nfor the partial decay widths $B \\rightarrow \\pi l \\nu_l)=\\vert V_{ub} \\vert^2\n(12 \\pm 8) 10^{12} s^{-1}$ and $\\Gamma(B \\rightarrow \\rho l \\nu_l)=\\vert V_{ub}\n\\vert^2 (13 \\pm12) 10^{12} s^{-1}$, which can be used to give upper bounds on\nthe rates"
    },
    {
        "anchor": "Evaluation of disconnected contributions using GPUs: We calculate on GPUs the disconnected diagrams associated with the nucleon\nform factors and moments of generalized parton distributions using Nf=2+1+1\ntwisted mass fermions. We employ the truncated solver method (TSM) for\nestimating the all-to-all propagators. Due to the fact that the TSM involves\nmany low precision stochastic estimators, the usage of GPUs is essential to\nperform efficiently the contractions and the inversions.",
        "positive": "A finite temperature investigation of dual superconductivity in the\n  modified SO(3) lattice gauge theory: We study the SO(3) lattice gauge theory in 3+1 dimensions with the adjoint\nWilson action modified by a $\\mathbb{Z}_2$ monopole suppression term and by\nmeans of the Pisa disorder operator. We find evidence for a finite temperature\ndeconfinement transition driven by the condensation of U(1) magnetic charges. A\nfinite-size scaling test shows consistency with the critical exponents of the\n3D Ising model."
    },
    {
        "anchor": "A further extension to the group of Ginsparg-Wilson (overlap) chiral\n  symmetries: As shown by Mandula, the Ginsparg-Wilson lattice realisation of chiral\nsymmetry has a possible ambiguity: there is no unique lattice chiral symmetry,\nbut an infinite group of symmetries with non-commuting generators. The physical\nimplications of this abundance of symmetry remain unclear. In recent work, it\nhas been shown how these chiral symmetries for overlap fermions can be derived\nfrom a renormalisation group blocking in the continuum, transforming the action\nfrom the standard continuum action to an equivalent to the lattice overlap\naction. There is no unique blocking, and different blockings lead to different\nchiral symmetries. The group of symmetries found by Mandula immediately\nfollows. In this way, the excess chiral symmetry on the lattice can be\nexplained in terms of different renormalisation schemes.\n  The previous work suffered from one technical challenge: there is no\ncontinuum analogue of the lattice chiral eigenvectors at eigenvalue $2/a$. As\nthe construction of the overlap operator required a mapping between lattice and\ncontinuum eigenvalues, the lack of a continuum counterpart to the doublers of\nthe zero modes creates an ambiguity in the construction. Although the lattice\nchiral symmetry can still be defined, this leads to difficulties when\nconsidering $\\mathcal{CP}$ symmetry on the lattice. In this work, we\ninvestigate the possibility of resolving this ambiguity by adding a second\nfermion field to the original continuum action used as a basis of the\nrenormalisation group blockings. This second fermion field has a mass of the\norder of the momentum cut-off, to simulate the effects of the fermion doublers.\nWorking through the same renormalisation group procedure to map this action to\nthe lattice overlap action yields additional Ginsparg-Wilson relations\nsatisfied by the overlap operator, and more (non-commuting) lattice chiral\nsymmetries.",
        "positive": "Wilson fermions in the epsilon regime: We extend the epsilon-expansion of continuum chiral perturbation theory to\nnonzero lattice spacing in the framework of Wilson Chiral Perturbation Theory.\nWe distinguish various regimes by defining the relative power counting of the\nquark mass m and the lattice spacing a. We observe that for m ~ a Lambda^2_QCD,\nthe explicit breaking of chiral symmetry in Wilson fermions is still driven by\nthe quark mass and lattice corrections are highly suppressed. The lattice\nspacing effects become more pronounced for smaller quark masses and may lead to\nnon-trivial corrections of the continuum results at next-to-leading order. We\ncompute these corrections for standard current and density correlation\nfunctions. A fit to lattice data shows that these corrections are small, as\nexpected."
    },
    {
        "anchor": "Random center vortex lines in continuous 3D space-time: We present a model of center vortices, represented by closed random lines in\ncontinuous 2+1- dimensional space- time. These random lines are modeled as\nbeing piece-wise linear and an ensemble is generated by Monte Carlo methods.\nThe physical space in which the vortex lines are defined is a cuboid with\nperiodic boundary conditions. Besides moving, growing and shrinking of the\nvortex configuration, also reconnections are allowed. Our ensemble therefore\ncontains not a fixed, but a variable number of closed vortex lines. This is\nexpected to be important for realizing the deconfining phase transition. Using\nthe model, we study both vortex percolation and the potential V (R) between\nquark and anti-quark as a function of distance R at different vortex densities,\nvortex segment lengths, reconnection conditions and at different temperatures.\nWe have found three deconfinement phase transitions, as a function of density,\nas a function of vortex segment length, and as a function of temperature. The\nmodel reproduces the qualitative features of confinement physics seen in SU(2)\nYang-Mills theory.",
        "positive": "Adaptive Optimization of Wave Functions for Fermion Lattice Models: We present a simulation algorithm for Hamiltonian fermion lattice models. A\nguiding trial wave function is adaptively optimized during Monte Carlo\nevolution. We apply the method to the two dimensional Gross-Neveu model and\nanalyze systematc errors in the study of ground state properties. We show that\naccurate measurements can be achieved by a proper extrapolation in the\nalgorithm free parameters."
    },
    {
        "anchor": "Seed methods for linear equations in lattice qcd problems with multiple\n  right-hand sides: We consider three improvements to seed methods for Hermitian linear systems\nwith multiple right-hand sides: only the Krylov subspace for the first system\nis used for seeding subsequent right-hand sides, the first right-hand side is\nsolved past convergence, and periodic re-orthogonalization is used in order to\ncontrol roundoff errors associated with the Conjugate Gradient algorithm. The\nmethod is tested for the case of Wilson fermions near kappa critical and a\nconsiderable speed up in the convergence is observed.",
        "positive": "Towards the quark mass dependence of $T_{cc}^+$ from lattice QCD: The $DD^*$ scattering phase shifts in the $T_{cc}^+=cc\\bar{u}\\bar{d}$ channel\nare extracted from lattice QCD for five different charm quark masses and a\nfixed light-quark mass corresponding to $m_\\pi\\simeq 280$ MeV. The phase shifts\nare analysed employing two approaches: effective range expansion and\nLippmann-Schwinger equation derived in the effective field theory. In the\nlatter case, the results imply an attraction at short range parametrised by\ncontact terms and a slight repulsion at long range mediated by one-pion\nexchange with $m_\\pi >m_{D^*}-m_D$. The poles in the amplitude across the\ncomplex energy plane are extracted and their trajectories are discussed as the\ncharm quark mass is varied. Two complex conjugate poles corresponding to a\nresonance below threshold are found for $m_c$ close to the physical value. They\nturn into a pair of virtual states at the largest $m_c$ studied. With further\nincreasing $m_c$, one virtual pole representing $T_{cc}^+$ is expected to move\ntowards the two-body threshold and turn into a bound state. The light-quark\nmass dependence of the $T_{cc}^+$ pole is briefly discussed using the data on\n$DD^*$ scattering from other lattice collaborations."
    },
    {
        "anchor": "Electroweak box diagram contribution for pion and kaon decay from\n  lattice QCD: One of the sensitive probes of physics beyond the standard model is the test\nof the unitarity of the Cabbibo-Kobyashi-Maskawa (CKM) matrix. Current analysis\nof the first row is based on $|V_{ud}|$ from fourteen superallowed $0^+ \\to\n0^+$ nuclear $\\beta$ decays and $|V_{ud}|$ from the kaon semileptonic decay, $K\n\\to \\pi \\ell \\nu_\\ell$. Modeling the nuclear effects in the $0^+ \\to 0^+$\ndecays is a major source of uncertainty, which would be absent in neutron\ndecays. To make neutron decay competitive requires improving the measurement of\nneutron lifetime and the axial charge, as well as the calculation of the\nradiative corrections (RC) to the decay. The largest uncertainty in these RCs,\nwhich comes from the non-perturbative part of the $\\gamma W$-box diagram and\nits evaluation using lattice QCD, is still not under control. Here, we show\nthat the analogous calculations for the pion and kaon decays are robust and\ngive $\\square_{\\gamma W}^{VA}|_{\\pi} = 2.810 (26) \\times 10^{-3}$ and\n$\\square_{\\gamma W}^{VA}|_{K^{0, S U(3)}} = 2.389 (17) \\times 10^{-3}$ in\nagreement with the previous analysis carried out by Feng et al. using a\ndifferent discretization of the fermion action.",
        "positive": "Chiral perturbation theory, K to pi pi decays and 2+1 flavor domain wall\n  QCD: We present a calculation of the low energy constants describing the real and\nimaginary parts of the $K \\to \\pi \\pi$ decay amplitudes $A_0$ and $A_2$.\nLeading and next leading order chiral perturbation theory is used and its\napplicability assessed. A combination of statistical and systematic errors\nlimits the precision of the results. The apparent limitations of chiral\nperturbation theory raise doubts about the accuracy of a possible extrapolation\nto physical $K \\to \\pi \\pi$ kinematics."
    },
    {
        "anchor": "Effects of near-zero Dirac eigenmodes on axial U(1) symmetry at finite\n  temperature: We study the axial U(1)A symmetry of Nf = 2 QCD at finite temperature using\nthe Dirac eigenvalue spectrum. The gauge configurations are generated employing\nthe Mobius domain-wall fermion action on 16^3x8 and 32^3x8 lattices. The\nphysical spatial size of these lattices is around 2 fm and 4 fm, respectively,\nand the simulated temperature is around 200 MeV, which is slightly above the\ncritical temperature of the chiral phase transition. Although the Mobius\ndomain-wall Dirac operator is expected to have a good chiral symmetry and our\ndata actually show small values of the residual mass, we observe significant\nviolation of the Ginsparg-Wilson relation for the low- lying eigenmodes of the\nMobius domain-wall Dirac operator. Using the reweighting technique, we compute\nthe overlap-Dirac operator spectrum on the same set of configurations and find\na significant difference of the spectrum between the two Dirac operators for\nthe low-lying eigenvalues. The overlap-Dirac spectrum shows a gap from zero,\nwhich is insensitive to the spacial volume.",
        "positive": "Approaches to inclusive semileptonic $B_{(s)}$-meson decays from Lattice\n  QCD: We address the nonperturbative calculation of the inclusive decay rate of\nsemileptonic $B_{(s)}$-meson decays from lattice QCD. Precise Standard-Model\npredictions are key ingredients in searches for new physics, and this type of\ncomputation may eventually provide new insight into the long-standing tension\nbetween the inclusive and exclusive determinations of the\nCabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_{cb}|$ and $|V_{ub}|$. We\npresent results from a pilot lattice computation for $B_s \\rightarrow X_c\\, l\n\\nu_l$, where the initial $b$ quark described by the relativistic-heavy-quark\n(RHQ) formalism on the lattice and the other valence quarks discretised with\ndomain-wall fermions are simulated approximately at their physical quark\nmasses. We compare two different methods for computing the decay rate from\nlattice data of Euclidean $n$-point functions, namely Chebyshev and\nBackus-Gilbert approaches. We further study how much the ground-state meson\ndominates the inclusive decay rate and indicate our strategy towards a\ncomputation with a more comprehensive systematic error budget."
    },
    {
        "anchor": "Remark on the Theoretical Uncertainty in $B^0$-$\\bar{B}^0$ Mixing: We re-examine the theoretical uncertainty in the Standard Model expression\nfor $B^0$-$\\bar{B}^0$ mixing. We focus on lattice calculations of the ratio\n$\\xi$, needed to relate the oscillation frequency of $B^0_s$-$\\bar{B}^0_s$\nmixing to $V_{td}$. We replace the usual linear chiral extrapolation with one\nthat includes the logarithm that appears in chiral perturbation theory. We find\na significant shift in the ratio $\\xi$, from the conventional $1.15\\pm0.05$ to\n$\\xi=1.32\\pm0.10$.",
        "positive": "Confinement in non-Abelian lattice gauge theory via persistent homology: We investigate the structure of confining and deconfining phases in SU(2)\nlattice gauge theory via persistent homology, which gives us access to the\ntopology of a hierarchy of combinatorial objects constructed from given data.\nSpecifically, we use filtrations by traced Polyakov loops, topological\ndensities, holonomy Lie algebra fields, as well as electric and magnetic\nfields. This allows for a comprehensive picture of confinement. In particular,\ntopological densities form spatial lumps which show signatures of the classical\nprobability distribution of instanton-dyons. Signatures of well-separated dyons\nlocated at random positions are encoded in holonomy Lie algebra fields,\nfollowing the semi-classical temperature dependence of the instanton appearance\nprobability. Debye screening discriminating between electric and magnetic\nfields is visible in persistent homology and pronounced at large gauge\ncoupling. All employed constructions are gauge-invariant without a priori\nassumptions on the configurations under study. This work showcases the\nversatility of persistent homology for statistical and quantum physics studies,\nbarely explored to date."
    },
    {
        "anchor": "A variant approach to the overlap action: I describe an implementation of the overlap action, which is built from an\naction which is itself an approximate overlap action. It appears to be about a\nfactor of 15-20 less expensive to use, than the usual overlap action with the\nWilson fermion action as its kernel. Ingredients include a fat link to suppress\ncoupling to dislocations and a free field action with a spectrum which\nresembles an overlap; much of the gain comes from the use of eigenmodes of the\napproximate action to begin the overlap calculation. As a physics example, I\ncompute the quark condensate in finite volume in the quenched approximation.",
        "positive": "Medium Effects in Parton Distributions: Understanding the effects of a background hadronic medium on hadronic\nobservables is important in the context of hadron structure. Many experiments\nprobing nucleon structure make use of nuclear targets and unraveling the\nmodifications that ensue is a complex task. Using lattice QCD, we investigate\nthe ab initio computation of hadron structure in a medium, focusing on the\nstructure of the pion in a Bose-condensed gas of pions."
    },
    {
        "anchor": "The Calculation of Critical Amplitudes in SU(2) Lattice Gauge Theory: We calculate the critical amplitudes of the Polyakov loop and its\nsusceptibility at the deconfinement transition of (3+1) dimensional SU(2) gauge\ntheory. To this end we study the corrections due to irrelevant exponents in the\nscaling functions. As a guiding line for determining the critical amplitudes we\nuse envelope equations which we derive from the finite size scaling formulae of\nthe observables. We have produced new high precision data on N^3 x 4 lattices\nfor N=12,18,26 and 36. With these data we find different corrections to the\nasymptotic scaling behaviour above and below the transition. Our result for the\nuniversal ratio of the susceptibility amplitudes is C_+/C_-=4.72(11) and thus\nin excellent agreement with a recent measurement for the 3d Ising model.",
        "positive": "Quantum Monte Carlo for Gauge Fields and Matter without the Fermion\n  Determinant: Ab-initio Monte Carlo simulations of strongly-interacting fermionic systems\nare plagued by the fermion sign problem, making the non-perturbative study of\nmany interesting regimes of dense quantum matter, or of theories of odd numbers\nof fermion flavors, challenging. Moreover, typical fermion algorithms require\nthe computation (or sampling) of the fermion determinant. We focus instead on\nthe meron cluster algorithm, which can solve the fermion sign problem in a\nclass of models without involving the determinant. We develop and benchmark new\nmeron algorithms to simulate fermions coupled to $\\mathbb{Z}_2$ and $U(1)$\ngauge fields in the presence of appropriate four-fermi interactions. Such\nalgorithms can be used to uncover potential exotic properties of matter,\nparticularly relevant for quantum simulator experiments. We demonstrate the\nemergence of the Gauss' Law at low temperatures for a $U(1)$ model in\n$(1+1)-$d."
    },
    {
        "anchor": "Schwinger-Dyson Study for Walking/Conformal Dynamics with IR Cutoffs: Motivated by recent progress on many flavor QCD on a lattice, we investigate\nconformal/walking dynamics by using Schwinger-Dyson (SD) equation within an\nimproved ladder approximation for two-loop running coupling. By numerically\nsolving the SD equation, we obtain a pole mass $m_{p}$, pion decay constant\n$f_{\\pi}$, and investigate the chiral symmetry breaking and mass anomalous\ndimension $\\gamma_{m}$ in the presence of IR cutoffs $\\Lambda_{\\mathrm{IR}}$.\nWe find that the chiral symmetry breaking is suppressed \\ if IR cutoff\n$\\Lambda_{\\mathrm{IR}}$ becomes larger than the critical \\ value near the\ndynamical mass ($\\Lambda_{\\mathrm{IR}}$ $\\simeq m_{D}$) In the conformal phase\nthe $\\gamma_{m}$ is strongly suppressed by IR cutoffs for $\\Lambda\n_{\\mathrm{IR}}$ $\\simeq m_{p}$. We, then, obtain finite size hyperscaling (FSS)\nrelation by adapting a linearized approximation for the SD equation, and\nexamine the $\\gamma_{m}$ The results offer valuable insight and suggestion for\nanalyses in lattice gauge theories.",
        "positive": "Zb tetraquark channel and $B\\bar B^*$ interaction from lattice QCD: Two tetraquark candidates $Z_b(10610)$ and $Z_b(10650)$ with flavor structure\n$\\bar bb\\bar du$ were discovered by Belle experiment in 2011. We present a\npreliminary $N_f=2$ lattice study of the $\\bar bb\\bar du$ system in the\napproximation of static $b$ quarks, where the total spin of heavy quarks is\nfixed to one. The ground and the excited eigen-energies are determined as a\nfunction of separation $r$ between $b$ and $\\bar b$. The lower eigenstates are\nrelated to a bottomonium and a pion. One of the higher eigenstates is dominated\nby $B\\bar B^*$: its energy is significantly below $m_B+m_{B*}$ for r=[0.1,0.4]\nfm, which suggests sizable attraction. The attractive potential $V(r)$ between\n$B$ and $\\bar B^*$ is extracted assuming that this eigenstate is related\nexclusively to $B\\bar B^*$. Assuming a certain form of the potential and\nsolving non-relativistic Schrodinger equation, we find a bound state pole below\n$B\\bar B^*$ threshold. For certain parametrizations, the bound state is very\nclose to the $B\\bar B^*$ threshold - this feature could be related to\n$Z_b(10610)$ in the experiment."
    },
    {
        "anchor": "Pion electromagnetic form factor from full lattice QCD: We present the first calculation of the pion electromagnetic form factor at\nphysical light quark masses. This form factor parameterises the deviations from\nthe behaviour of a point-like particle when a photon hits the pion. These\ndeviations result from the internal structure of the pion and can thus be\ncalculated in QCD. We use three sets (different lattice spacings) of $n_f =\n2+1+1$ lattice configurations generated by the MILC collaboration. The Highly\nImproved Staggered Quark formalism (HISQ) is used for all of the sea and\nvalence quarks. Using lattice configurations with $u$/$d$ quark masses very\nclose to the physical value is a big advantage, as we avoid the chiral\nextrapolation. We study the shape of the vector ($f_+$) form factor in the\n$q^2$ range from $0$ to $-0.15$~GeV$^2$ and extract the mean square radius,\n$\\langle r^2_v\\rangle$. The shape of the vector form factor and the resulting\nradius is compared with experiment. We also discuss the scalar form factor and\nradius extracted from that, which is not directly accessible to experiment. We\nhave also calculated the contributions from the disconnected diagrams to the\nscalar form factor at small $q^2$ and discuss their impact on the scalar radius\n$\\langle r^2_s\\rangle$.",
        "positive": "Understanding chiral symmetry breaking with the overlap action: A chiral fermion action allows one to do very clean studies of chiral\nsymmetry breaking in QCD. I will briefly describe how to compute with the\noverlap action (relatively) cheaply, and then turn to physics: Low modes of the\nDirac operator show a ``lumped'' chiral density which peaks at the locations of\ninstantons and anti-instantons. These modes dominate correlation functions at\nsmall quark mass in many channels. The picture qualitatively (and in some cases\nquantitatively) resembles an instanton liquid model."
    },
    {
        "anchor": "Electromagnetic conductivity of quark-gluon plasma at non-zero baryon\n  density: In this preprint we present our results on the study of the electromagnetic\nconductivity in dense quark-gluon plasma obtained within lattice simulations\nwith $N_f = 2 + 1$ dynamical quarks. We employ stout improved rooted staggered\nquarks at the physical point and the tree-level Symanzik improved gauge action.\nThe simulations are performed at imaginary baryon chemical potential, and the\nTikhonov regularisation method is used to extract the conductivity from\ncurrent-current correlators. Our results indicate an increase of QGP\nelectromagnetic conductivity with real baryon density, and this dependence is\nquite strong.",
        "positive": "Beauty mesons in lattice QCD with exact chiral symmetry: We present the first study of treating b, c, and s quarks as Dirac fermions\nin lattice QCD with exact chiral symmetry. For 100 gauge configurations\ngenerated with single-plaquette action at beta = 7.2 on the 32^3 x 60 lattice,\nwe compute point-to-point quark propagators for 33 quark masses in the range\n0.01 < m_q a < 0.85, and measure the time-correlation function of\n(pseudo-)scalar, (pseudo-)vector, and tensor mesons, for symmetric and\nasymmetric quark masses respectively. The lowest-lying mass spectra of mesons\nwith quark contents b_bbar, c_bbar, s_bbar, and c_cbar are determined, together\nwith the pseudoscalar decay constants. Our results are sumarized in Tables 1-5.\nFurthermore, we also determine the b and c quark masses in the MS_bar scheme,\nm_b = 4.65(5) GeV, and m_c = 1.16(4) GeV."
    },
    {
        "anchor": "Studying the $\u03c1$ resonance parameters with staggered fermions: We deliver a lattice study of $\\rho$ resonance parameters with p-wave\n$\\pi\\pi$ scattering phases, which are extracted by finite-size methods at one\ncenter-of-mass frame and four moving frames for six MILC lattice ensembles with\npion masses ranging from $346$ to $ 176$ MeV. The effective range formula is\napplied to describe the scattering phases as a function of the energy covering\nthe resonance region, this allows us to extract $\\rho$ resonance parameters and\nto investigate the quark-mass dependence. Lattice studies with three flavors of\nthe Asqtad-improved staggered fermions enable us to use the moving-wall source\ntechnique on large lattice spatial dimensions ($L=64$) and small light $u/d$\nquarks. Numerical computations are carried out at two lattice spacings, $a\n\\approx 0.12$ and $0.09$ fm.",
        "positive": "Stochastic propagators for multi-pion correlation functions in lattice\n  QCD with GPUs: Motivated by the application of L\\\"uscher's finite volume method to the study\nof the lightest scalar resonance in the $\\pi\\pi \\to \\pi\\pi$ isoscalar channel,\nin this article we describe our studies of multi-pion correlation functions\ncomputed using stochastic propagators in quenched lattice QCD, harnessing GPUs\nfor acceleration. We consider two methods for constructing the correlation\nfunctions. One \"outer product\" approach becomes quite expensive at large\nlattice extent $L$, having an ${\\cal O}(L^7)$ scaling. The other \"stochastic\noperator\" approach scales as ${\\cal O}(N_r^2 L^4)$, where $N_r$ is the number\nof random sources. It would become more efficient if variance reduction\ntechniques are used and the volume is fairly large. It is also found that\ncorrelations between stochastic propagators appearing in the same diagram, when\na single set of random source vectors is used, lead to much larger errors than\nif separate random sources are used for each propagator. The calculations\ninvolve states with quantum numbers of the vacuum, so all-to-all propagators\nmust be computed. For this reason, GPUs are ideally suited to accelerating the\ncalculation. For this work we have integrated the Columbia Physics System (CPS)\nand QUDA GPU inversion library, in the case of clover fermions. Finally, we\nshow that the completely quark disconnected diagram is crucial to the results,\nand that neglecting it would lead to answers which are far from the true value\nfor the effective mass in this channel. This is unfortunate, because as we also\nshow, this diagram has very large errors, and in fact dominates the error\nbudget."
    },
    {
        "anchor": "Lattice QCD: bulk and transport properties of QCD matter: We present an overview of the most recent results on bulk and transport\nproperties of QCD matter inferred from lattice QCD simulations.",
        "positive": "Chiral Symmetry Restoration and $Z_N$ Symmetry: We demonstrate that chiral symmetry restoration in quenched finite\ntemperature QCD depends crucially on the $Z_3$ phase of the Polyakov loop\n${\\cal P}$. This dependence is a general consequence of the coupling of the\nchiral order parameter to the Polyakov loop. We construct a model for chiral\nsymmetry breaking and restoration which includes the effect of a nontrivial\nPolyakov loop by calculating the effective potential for the chiral condensate\nof a Nambu-Jona-Lasinio model in a uniform temperature dependent $A_0$ gauge\nfield background. Above the deconfinement temperature there are three possible\nphases corresponding to the $Z_3$ symmetric phases of the Polyakov loop in the\npure gauge theory. In the phase in which ${\\rm tr_c}({\\cal P})$ is real and\npositive the first order deconfining transition induces chiral symmetry\nrestoration in agreement with simulation results. In the two phases where\n$Re[{\\rm tr_c}({\\cal P})] < 0$ the sign of the leading finite temperature\ncorrection to the effective potential is reversed from the normal phase, and\nchiral symmetry is not restored at the deconfinement transition; this agrees\nwith the recent simulation studies of Chandrasekharan and Christ. In the case\nof $SU(N)$ a rich set of possibilites emerges. The generality of the mechanism\nmakes it likely to occur in full QCD as well; this will increase the lifetimes\nof metastable $Z_3$ phases."
    },
    {
        "anchor": "On the ratio of string tensions in the 3D Z_4 lattice gauge theory: It was recently pointed out that simple scaling properties of Polyakov\ncorrelation functions of gauge systems in the confining phase suggest that the\nratios of k-string tensions in the low temperature region is constant up to\nterms of order T^3. Here we argue that, at least in a three-dimensional Z_4\ngauge model, the above ratios are constant in the whole confining phase. This\nresult is obtained by combining numerical experiments with known exact results\non the mass spectrum of an integrable two-dimensional spin model describing the\ninfrared behaviour of the gauge system near the deconfining transition.",
        "positive": "Regularization dependence of the Higgs mass triviality bound: We calculate the triviality bound on the Higgs mass in scalar field theory\nmodels whose global symmetry group $SU(2)_L \\times SU(2)_{\\rm custodial}\n\\approx O(4)$ has been replaced by $O(N)$ and $N$ has been taken to infinity.\nLimits on observable cutoff effects at four percent in several regularized\nmodels with tunable couplings in the bare action yield triviality bounds\ndisplaying a large degree of universality. Extrapolating from $N=\\infty$ to\n$N=4$ we conservatively estimate that a Higgs particle with mass up to\n$0.750~TeV$ and width up to $0.290~TeV$ is realizable without large cutoff\neffects, indicating that strong scalar self interactions in the standard model\nare not ruled out. We also present preliminary numerical results of the\nphysical $N=4$ case for the $F_4$ lattice that are in agreement with the large\n$N$ expectations. Note: The full ps file is also available via anonymous ftp to\nftp.scri.fsu.edu. To get the ps file, ftp to this address and use for username\n\"anonymous\" and for password your name. The file is in the directory pub/vranas\n(to go to that directory type: cd pub/vranas) and is called lat92_proc.ps (to\nget it type: get lat92_proc.ps)"
    },
    {
        "anchor": "Three-body Unitarity in the Finite Volume: The physical interpretation of lattice QCD simulations, performed in a small\nvolume, requires an extrapolation to the infinite volume. A method is proposed\nto perform such an extrapolation for three interacting particles at energies\nabove threshold. For this, a recently formulated relativistic $3\\to 3$\namplitude based on the isobar formulation is adapted to the finite volume. The\nguiding principle is two- and three-body unitarity that imposes the imaginary\nparts of the amplitude in the infinite volume. In turn, these imaginary parts\ndictate the leading power-law finite-volume effects. It is demonstrated that\nfinite-volume poles arising from the singular interaction, from the external\ntwo-body sub-amplitudes, and from the disconnected topology cancel exactly\nleaving only the genuine three-body eigenvalues. The corresponding quantization\ncondition is derived for the case of three identical scalar-isoscalar particles\nand its numerical implementation is demonstrated.",
        "positive": "The analytic structure of the lattice Landau gauge gluon and ghost\n  propagators: Starting from the lattice Landau gauge gluon and ghost propagator data we use\na sequence of Pad\\'e approximants, identify the poles and zeros for each\napproximant and map them into the analytic structure of the propagators. For\nthe Landau gauge gluon propagator the Pad\\'e analysis identifies a pair of\ncomplex conjugate poles and a branch cut along the negative real axis of the\nEuclidean $p^2$ momenta. For the Landau gauge ghost propagator the Pad\\'e\nanalysis shows a single pole at $p^2 = 0$ and a branch cut also along the\nnegative real axis of the Euclidean $p^2$ momenta. The method gives precise\nestimates for the gluon complex poles, that agree well with other estimates\nfound in the literature. For the branch cut the Pad\\'e analysis gives, at\nleast, a rough estimate of the corresponding branch point."
    },
    {
        "anchor": "Establishment of the Coulomb law in the layer phase of a pure U(1)\n  lattice gauge theory: In this article we examine the Layer phase of the five dimensional,\nanisotropic, Abelian gauge model. Our results are to be compared with the ones\nof the 4D U(1) gauge model in an attempt to verify that four dimensional\nphysics governs the four dimensional layers. The main results are: i) From the\nanalysis of Wilson loops we verified the $\\frac{1}{R}$ behavior, in the layered\nphase, for the potential between heavy charges. The renormalized fine structure\nconstant in the layer phase is found to be equal to that of 4D Coulomb\nphase,$\\alpha_{layer}$=$\\alpha_{4D}$. ii) Based on the helicity modulus\nanalysis we show that the layers are in the Coulomb phase while the transverse\nbulk space is in the confining phase. We also calculated the renormalized\ncoupling $\\beta_{R}$ and found results compatible with those obtained from the\nCoulomb potential. Finally we calculated the potential in the 5D Coulomb phase\nand found $\\frac{1}{R^{2}}$ behavior for the static $q \\bar{q}$ potential. From\nthe study of the helicity modulus we have a possible estimate for the five\ndimensional renormalized fine structure constant in the region of the critical\nvalue of the bare gauge coupling.",
        "positive": "Zero temperature phase structure of multi-flavor QCD: To study continuum limit of lattice QCD with many light quark flavors, we\ninvestigate the zero temperature phase structures of multi-flavor QCD.\nCurrently a series of exploratory simulations are being performed with the\nnumber of quark flavors, $N_f $= 6, 8, and 10 on a set of lattice volumes for\nvarious quark masses. Here, we report on the current status of our simulation\non a $8^4$ lattice."
    },
    {
        "anchor": "On-shell improved lattice QCD with staggered fermions: By using Symanzik's improvement program, we study on-shell improved lattice\nQCD with staggered fermions. We find that there are as many as 15 independent\nlattice operators of dimension of six~(including both gauge and fermion\noperators) which must be added to the unimproved action to form an $O(a^2)$\nimproved action. Among them, the total number of dimension-6 gauge operators\nand fermion bilinears is 5. The other 10 terms are four-fermion operators. At\nthe tree-level and tadpole-improved tree-level, all the 10 four fermion\noperators are absent.",
        "positive": "Complex Langevin dynamics in the SU(3) spin model at nonzero chemical\n  potential revisited: The three-dimensional SU(3) spin model is an effective Polyakov loop model\nfor QCD at nonzero temperature and density. It suffers from a sign problem at\nnonzero chemical potential. We revisit this model using complex Langevin\ndynamics and assess in particular the justification of this approach, using\nanalyticity at small mu^2 and the criteria for correctness developed recently.\nFinite-stepsize effects are discussed in some detail and a higher-order\nalgorithm is employed to eliminate leading stepsize corrections. Our results\nstrongly indicate that complex Langevin dynamics is reliable in this theory in\nboth phases, including the critical region. This is in sharp contrast to the\ncase of the XY model, where correct results were obtained in only part of the\nphase diagram."
    },
    {
        "anchor": "O(a) improvement of the axial current in lattice QCD to one-loop order\n  of perturbation theory: The conservation of the isovector axial current in lattice QCD with massless\nWilson quarks is studied to one-loop order of perturbation theory. Following a\nstrategy described in a previous publication, the O($a$) counterterm required\nfor on-shell improvement of the current is computed. We also confirm an earlier\nresult of Wohlert for the coefficient in front of the SW term in the improved\naction.",
        "positive": "Monopoles in the Abelian Projection of Gluodynamics: We discuss some properties of the abelian monopoles in compact U(1) gauge\ntheory and in the SU(2) gluodynamics both on the lattice and in the continuum."
    },
    {
        "anchor": "Hadron-hadron interaction from SU(2) lattice QCD: We evaluate interhadron interactions in two-color lattice QCD from\nBethe-Salpeter amplitudes on the Euclidean lattice. The simulations are\nperformed in quenched SU(2) QCD with the plaquette gauge action at $\\beta =\n2.45$ and the Wilson quark action. We concentrate on S-wave scattering states\nof two scalar diquarks. Evaluating different flavor combinations with various\nquark masses, we try to find out the ingredients in hadronic interactions.\nBetween two scalar diquarks ($u C\\gamma_5 d$, the lightest baryon in SU(2)\nsystem), we observe repulsion in short-range region, even though present quark\nmasses are not very light. We define and evaluate the \"quark-exchange part\" in\nthe interaction, which is induced by adding quark-exchange diagrams, or\nequivalently, by introducing Pauli blocking among some of quarks. The repulsive\nforce in short-distance region arises only from the \"quark-exchange part\", and\ndisappears when quark-exchange diagrams are omitted. We find that the strength\nof repulsion grows in light quark-mass regime and its quark-mass dependence is\nsimilar to or slightly stronger than that of the color-magnetic interaction by\none-gluon-exchange (OGE) processes. It is qualitatively consistent with the\nconstituent-quark model picture that a color-magnetic interaction among quarks\nis the origin of repulsion. We also find a universal long-range attractive\nforce, which enters in any flavor channels of two scalar diquarks and whose\ninteraction range and strength are quark-mass independent. The weak quark-mass\ndependence of interaction ranges in each component implies that meson-exchange\ncontributions are small and subdominant, and the other contributions, {\\it ex.}\nflavor exchange processes, color-Coulomb or color-magnetic interactions, are\nconsidered to be predominant, in the quark-mass range we evaluated.",
        "positive": "Gluon mass generation and infrared Abelian dominance in Yang-Mills\n  theory: The dual superconductivity is believed to be a promising mechanism for quark\nconfinement. Indeed, what this picture is true has been confirmed in the\nmaximal Abelian (MA) gauge. However, it is not yet confirmed in any other gauge\nand the MA gauge explicitly breaks color symmetry. To remedy this defect, we\npropose to use our compact formulation of a non-linear change of variables on a\nlattice. This formulation has succeeded to extract the magnetic monopole with\ninteger-valued magnetic charge in the gauge-invariant way. In this talk, we\npresent measurements of various correlation functions for the operators\nconstructed from the CFN variables in SU(2) Yang-Mills theory. Some of our\nresults reproduce previous results obtained in MA gauge, e.g.,\nDeGrant-Toussaint monopole, infrared Abelian dominance and off-diagonal gluon\nmass generation. These studies preserve color symmetry, in sharp contrast to\nthe conventional MA gauge. We argue the gauge fixing independence of these\nresults and the implications to quark confinement"
    },
    {
        "anchor": "Asymptotic transition from Fourier series to integrals in LGT: It is shown that in asymptotic transition from Fourier series to integrals an\nerror and ambiguity may arise. Ambiguity reduces to a possibility of addition\nof some distribution to the result. Properties of such distributions are\nstudied and conditions are established under which ambiguity doesn't arise.\nMethod for correction computation is suggested and conditions for correction\nturning to zero are specified.",
        "positive": "Fluctuations and Correlations of net baryon number, electric charge, and\n  strangeness: A comparison of lattice QCD results with the hadron resonance\n  gas model: We calculate the quadratic fluctuations of net baryon number, electric charge\nand strangeness as well as correlations among these conserved charges in\n(2+1)-flavor lattice QCD at zero chemical potential. Results are obtained using\ncalculations with tree level improved gauge and the highly improved staggered\nquark (HISQ) actions with almost physical light and strange quark masses at\nthree different values of the lattice cut-off. Our choice of parameters\ncorresponds to a value of 160 MeV for the lightest pseudo scalar Goldstone mass\nand a physical value of the kaon mass. The three diagonal charge\nsusceptibilities and the correlations among conserved charges have been\nextrapolated to the continuum limit in the temperature interval 150 MeV <T <\n250 MeV. We compare our results with the hadron resonance gas (HRG) model\ncalculations and find agreement with HRG model results only for temperatures\nT<= 150 MeV. We observe significant deviations in the temperature range 160 MeV\n< T < 170 MeV and qualitative differences in the behavior of the three\nconserved charge sectors. At T < 160 MeV quadratic net baryon number\nfluctuations in QCD agree with HRG model calculations while, the net electric\ncharge fluctuations in QCD are about 10% smaller and net strangeness\nfluctuations are about 20% larger. These findings are relevant to the\ndiscussion of freeze-out conditions in relativistic heavy ion collisions."
    },
    {
        "anchor": "Leading isospin-breaking effects on the lattice: Isospin is an almost exact symmetry of strong interactions and the\ncorrections to the isosymmetric limit are, in general, at the percent level.\nFor several hadronic quantities, such as pseudoscalar meson masses or the kaon\nleptonic and semileptonic decay rates, these effects are of the same order of\nmagnitude of the errors quoted in nowadays lattice calculations and cannot be\nneglected any longer. In this talk I discuss some recent results for the\npseudoscalar meson spectrum obtained by the RM123 Collaboration including\nisospin breaking corrections in first principles lattice simulations.",
        "positive": "Temperature dependence of shear viscosity of $SU(3)$--gluodynamics\n  within lattice simulation: In this paper we study the shear viscosity temperature dependence of\n$SU(3)$--gluodynamics within lattice simulation. To do so, we measure the\ncorrelation functions of energy-momentum tensor in the range of temperatures\n$T/T_c\\in [0.9, 1.5]$. To extract the values of shear viscosity we used two\napproaches. The first one is to fit the lattice data with some physically\nmotivated ansatz for the spectral function with unknown parameters and then\ndetermine shear viscosity. The second approach is to apply the Backus-Gilbert\nmethod which allows to extract shear viscosity from the lattice data\nnonparametrically. The results obtained within both approaches agree with each\nother. Our results allow us to conclude that within the temperature range\n$T/T_c \\in [0.9, 1.5]$ SU(3)--gluodynamics reveals the properties of a strongly\ninteracting system, which cannot be described perturbatively, and has the ratio\n$\\eta/s$ close to the value ${1}/{4\\pi}$ in $N = 4$ Supersymmetric Yang-Mills\ntheory."
    },
    {
        "anchor": "Lattice NRQCD study of S- and P-wave bottomonium states in a thermal\n  medium with $N_f=2+1$ light flavors: We investigate the properties of S-and P-wave bottomonium states in the\nvicinity of the deconfinement transition temperature. The light degrees of\nfreedom are represented by dynamical lattice QCD configurations of the HotQCD\ncollaboration with $N_f = 2 + 1$ flavors. Bottomonium correlators are obtained\nfrom bottom quark propagators, computed in nonrelativistic quantum\nchromodynamics (NRQCD) under the background of these gauge field\nconfigurations. The spectral functions for the $^3S_1$ ($\\Upsilon$) and $^3P_1$\n($\\chi_{b1}$) channel are extracted from the Euclidean time correlators using a\nnovel Bayesian approach in the temperature region $140 {\\rm MeV} \\le T \\le 249\n{\\rm MeV}$ and the results are contrasted to those from the standard maximum\nentropy method. We find that the new Bayesian approach is far superior to the\nmaximum entropy method. It enables us to study reliably the presence or absence\nof the lowest state signal in the spectral function of a certain channel, even\nunder the limitations present in the finite temperature setup. We find that\n$\\chi_{b1}$ survives up to $T=249 {\\rm MeV}$, the highest temperature\nconsidered in our study and put stringent constraints on the size of the medium\nmodification of $\\Upsilon$ and $\\chi_{b1}$ states.",
        "positive": "Critical behavior of SU(3) lattice gauge theory with 12 light flavors: It is expected that when the number of light flavors of gauge theories is\nincreased near or beyond some critical value, new and interesting behavior\noccurs. We discuss the qualitative properties of the RG flows for a local\n$SU(3)$ theory with $N_f$ light fundamental flavors for $N_f$ near 12. We\ndiscuss the realization of the chiral symmetry and remind that the Wigner mode\nseems an unlikely alternative. We propose to use a linear sigma model to\ndescribe the light $\\sigma$ masses found in recent lattice calculations for\n$N_f$=8 and 12. Progress made after the conference are reported in\narXiv:1709.09264, where it is claimed that the breaking of the axial $U(1)_A$\nis a key ingredient to get a small $\\sigma$ mass. For SU(3) lattice gauge\ntheory with 12 flavors of unimproved staggered fermions, the scaling of the\nimaginary part of the zeros of the partition function in the complex coupling\nplane is consistent with a first order phase transition for small values of the\nmass. Zech Gelzer and Diego Floor are investigating the scaling near the\nendpoint of the line of first order phase transition in the mass-coupling plane\nwhere a light and weakly interacting scalar is expected. We briefly discuss\nrecent calculations of the second-order R\\'enyi entanglement entropy and\nestimations of the central charge using the Tensor Renormalization Group method\nfor the two-dimensional O(2) model and the possibility to extend these\ncalculations to higher dimensions."
    },
    {
        "anchor": "Chiral Extrapolations and the Covariant Small Scale Expansion: We calculate the nucleon and the delta mass to fourth order in a covariant\nformulation of the small scale expansion. We analyze lattice data from the MILC\ncollaboration and demonstrate that the available lattice data combined with our\nknowledge of the physical values for the nucleon and delta masses lead to\nconsistent chiral extrapolation functions for both observables up to fairly\nlarge pion masses. This holds in particular for very recent data on the delta\nmass from the QCDSF collaboration. The resulting pion-nucleon sigma term is\nsigma_{piN} = 48.9 MeV. This first quantitative analysis of the quark-mass\ndependence of the structure of the Delta(1232) in full QCD within chiral\neffective field theory suggests that (the real part of) the nucleon-delta\nmass-splitting in the chiral limit, Delta_0 = 0.33 GeV, is slightly larger than\nat the physical point. Further analysis of simultaneous fits to nucleon and\ndelta lattice data are needed for a precision determination of the properties\nof the first excited state of the nucleon.",
        "positive": "Fixed point actions from convolutional neural networks: Lattice gauge-equivariant convolutional neural networks (L-CNNs) can be used\nto form arbitrarily shaped Wilson loops and can approximate any gauge-covariant\nor gauge-invariant function on the lattice. Here we use L-CNNs to describe\nfixed point (FP) actions which are based on renormalization group\ntransformations. FP actions are classically perfect, i.e., they have no lattice\nartifacts on classical gauge-field configurations satisfying the equations of\nmotion, and therefore possess scale invariant instanton solutions. FP actions\nare tree-level Symanzik-improved to all orders in the lattice spacing and can\nproduce physical predictions with very small lattice artifacts even on coarse\nlattices. We find that L-CNNs are much more accurate at parametrizing the FP\naction compared to older approaches. They may therefore provide a way to\ncircumvent critical slowing down and topological freezing towards the continuum\nlimit."
    },
    {
        "anchor": "Computation of the Vortex Free Energy in SU(2) Gauge Theory: We present the first measurement of the vortex free-energy order parameter at\nweak coupling for SU(2) in simulations employing multihistogram methods. The\nresult shows that the excitation probability for a sufficiently thick vortex in\nthe vacuum tends to unity. This is rigorously known to provide a necessary and\nsufficient condition for maintaining confinement at weak coupling in SU(N)\ngauge theories.",
        "positive": "Determining low-energy constants in partially quenched Wilson chiral\n  perturbation theory: In the low energy effective theory describing the partially quenched\nextension of two light Wilson fermions, three low energy constants (LECs)\nappear in terms proportional to a^2 (a being the lattice spacing). We propose\nmethods to separately calculate these LECs, typically called W'_6, W'_7 and\nW'_8. While only one linear combination of these constants enters into physical\nquantities, different combinations enter into the description of the spectral\ndensity and eigenvalue distributions of the lattice Dirac operator and its\nHermitian counterpart. Thus it is useful to be able to determine the LECs\nseparately. Our methods require studying certain correlation functions for\neither two or three pion scattering, which are accessible only in the partially\nquenched extension of the theory."
    },
    {
        "anchor": "\u03b7 and \u03b7' mixing from Lattice QCD: We present a lattice QCD computation of $\\eta$ and $\\eta^\\prime$ masses and\nmixing angles, for the first time controlling continuum and quark mass\nextrapolations. The results for the eta mass 551(8)(6) MeV (first error\nstatistical, second systematic) and the eta' mass 1006(54)(38)(+61) MeV (third\nerror from our method) are in excellent agreement with experiment. Our data\nshow that the mixing in the quark flavour basis can be described by a single\nmixing angle of 46(1)(3) degree indicating that the eta' is mainly a flavour\nsinglet state.",
        "positive": "New algorithm of the high-temperature expansion for the Ising model in\n  three dimensions: New algorithm of the finite lattice method is presented to generate the\nhigh-temperature expansion series of the Ising model. It enables us to obtain\nmuch longer series in three dimensions when compared not only to the previous\nalgorithm of the finite lattice method but also to the standard graphical\nmethod. It is applied to extend the high-temperature series of the simple cubic\nIsing model from beta^{26} to beta^{46} for the free energy and from beta^{25}\nto beta^{32} for the magnetic susceptibility."
    },
    {
        "anchor": "Canonical partition function and finite density phase transition in\n  lattice QCD: We discuss the nature of the phase transition for lattice QCD at finite\ntemperature and density. We propose a method to calculate the canonical\npartition function by fixing the total quark number introducing approximations\nallowed in the low density region. An effective potential as a function of the\nquark number density is discussed from the canonical partition function. We\nanalyze data obtained in a simulation of two-flavor QCD using p4-improved\nstaggered quarks with bare quark mass $m/T = 0.4$ on a $16^3 \\times 4$ lattice.\nThe results suggest that the finite density phase transition at low temperature\nis of first order.",
        "positive": "Can we decide whether QCD is confining or not at high temperature?: At high temperature measurements of the Polyakov loop suggest a deconfinement\ntransition to the (strongly interacting) quark-gluon plasma. At the same time\nat the infinitely large temperature the four-dimensional QCD is reduced to the\nthree-dimensional QCD that is confining. The Polyakov loop and related Z_3\nsymmetry are strict order parameters only for infinitely heavy quarks. In such\na situation the SU(2)_CS and SU(4) symmetries of confinement in the light quark\nsector could be helpful to distinguish between the confining and deconfining\nphase in a regime where SU(2)_L \\times SU(2)_R and U(1)_A symmetries are\nmanifest. In order to reveal a presence or absence of these symmetries one\nneeds to measure and compare correlation functions related by these symmetry\ntransformations."
    },
    {
        "anchor": "Subtleties of Non-Abelian Gauge Theories in Cold-Atomic Lattices: I point out two of the subtleties referred to in the title. The first is that\ngauge-invariant magnetic systems may realized under general circumstances, as\nsuggested by a simple theorem. The second subtlety is that care is needed to\nidentify the field theory simulated by a cold-atomic lattice gauge system.\nThough the simplest such model confines in 2+1 dimensions, it has\nnon-relativistic ``gluon\" excitations. Time-reversal invariance is\nspontaneously broken in this system. The confinement mechanism is related to an\nextra U(1) gauge invariance.There is a model, suggested long ago by D. Rohlich\nand me, which is known to have relativistic spin waves. One of the outstanding\ntheoretical problems is a better determination of the energy-momentum relation\nof spin waves in different magnetic gauge systems.",
        "positive": "The microscopic Twisted Mass Dirac spectrum and the spectral\n  determination of the LECs of Wilson $\u03c7$-PT: We present the comparison of the analytical microscopic spectral density for\nlattice QCD with $N_{\\rm f}=2$ twisted mass fermions with the one obtained on\nthe lattice utilizing configurations produced by the ETM collaboration. We\nextract estimates for the chiral condensate as well as the low-energy constant\n$W_8$ of Wilson $\\chi$-PT by employing spectral information of the Wilson Dirac\noperator with fixed index at finite volume."
    },
    {
        "anchor": "Advances and applications of lattice supersymmetry: I review motivations for the study of supersymmetric field theories by\nlattice techniques. In particular, some of the more interesting potential\napplications are described. These are models of quantum gravity, that rely on\nthe AdS/CFT correspondence. The dual gauge theory is an ideal place for lattice\nstudies to make a contribution. I also survey some of the recent advances in\nlattice formulations of supersymmetric theories.",
        "positive": "Finite Size Effects in Fluid Interfaces: It is shown that finite size effects in the free energy of a rough interface\nof the 3D Ising and three--state Potts models are well described by the\ncapillary wave model at {\\em two--loop} order. The agreement between\ntheoretical predictions and Monte Carlo simulations strongly supports the idea\nof the universality of this description of order--order interfaces in 3D\nstatistical systems above the roughening temperature."
    },
    {
        "anchor": "Towards an algebraic approach to the discretisation of fermions: A discretisation scheme for differential geometry is applied to the problem\nof constructing lattice actions, the naive and staggered action are thus\nderived. It is found that after specifying an ansatz for the space of fields,\nthe corresponding lattice action is obtained. The gauging procedure, and the\napplicability of the method to twisted super-symmetry on a lattice is outlined.\nSome comments on the QED axial anomaly are made, for the theory in which the\nlattice projection operator is not inserted.",
        "positive": "Further Evidence of a Smooth Phase in 4D Simplicial Quantum Gravity: Four-dimensional (4D) simplicial quantum gravity coupled to U(1) gauge fields\nhas been studied using Monte-Carlo simulations. A negative string\nsusceptibility exponent is observed beyond the phase-transition point, even if\nthe number of vector fields (NV) is 1. We find a scaling relation of the\nboundary volume distributions in this new phase. This scaling relation suggests\na fractal structure similar to that of 2D quantum gravity. Furthermore,\nevidence of a branched polymer-like structure is suggested far into the\nweak-coupling region, even for NV > 1. As a result, we propose new phase\nstructures and discuss the possibility of taking the continuum limit in a\ncertain region between the crumpled and branched polymer phases."
    },
    {
        "anchor": "$\u039b_{QCD}$ from gluon and ghost propagators: Fundamental quantities of QCD, such as the strong coupling and\n$\\Lambda_{QCD}$, are studied in the framework of lattice QCD with $N_f=2$\ntwisted mass fermions. In particular, the contact between lattice and\ncontinuous calculations is made by comparing the renormalized ghost-gluon\nvertex in MOM scheme with 4-loop perturbative results. A power correction is\nneeded in order to have agreement between the two descriptions. This suggests\nthe presence of a dimension-two $\\VEV{A^2}$ gluon condensate whose value is\nfound to be higher than in the quanched case.",
        "positive": "Lattice Prediction for Deeply Bound Doubly Heavy Tetraquarks: We investigate the possibility of $qq^\\prime \\bar b \\bar b$ tetraquark bound\nstates using $n_f=2+1$ lattice QCD ensembles with pion masses $\\simeq 164$,\n$299$, and $415$ MeV. Motivated by observations from heavy baryon\nphenomenology, we consider two lattice interpolating operators both of which\nare expected to couple efficiently to tetraquark states: one with\ndiquark-antidiquark and one with a meson-meson structure. Using nonrelativistic\nQCD to simulate the bottom quarks, we study the $ud\\bar b \\bar b$, $\\ell s\\bar\nb \\bar b$ channels with $\\ell=u,d$, and find unambiguous signals for\nstrong-interaction-stable $J^P=1^+$ tetraquarks. These states are found to lie\n$189(10)$ and $98(7)$ MeV below the corresponding free two-meson thresholds."
    },
    {
        "anchor": "Reducing Baryon Noise in Lattice QCD Through Partial Quenching: The study of nuclear physics using lattice QCD is hindered by an\nexponentially large signal-to-noise problem which is conventionally alleviated\nby raising the quark masses to unphysically high values. We propose a novel\nform of partial quenching for calculations involving nucleons in which the sea\nquark masses are taken to be smaller than the valence quark masses. It is shown\nthat lowering the sea quark masses toward their physical values actually\nimproves signal-to-noise. An optimized approach to the physical point in the\n(m_s, m_v) plane is proposed, with a full analysis of the cost benefit.\nImprovements in computing time of ~ 10^(2(A-1)), where A is the number of\nnucleons in the system, are shown to be possible.",
        "positive": "The Lattice Free Energy with Overlap Fermions: A Two-Loop Result: We calculate the 2-loop partition function of QCD on the lattice, using the\nWilson formulation for gluons and the overlap-Dirac operator for fermions.\nDirect by-products of our result are the 2-loop free energy and average\nplaquette. Our calculation serves also as a prototype for further higher loop\ncalculations in the overlap formalism. We present our results as a function of\na free parameter $M_0$ entering the overlap action; the dependence on the\nnumber of colors $N$ and fermionic flavors $N_f$ is shown explicitly."
    },
    {
        "anchor": "Study of QCD critical point using canonical ensemble method: The existence of the QCD critical point at non-zero baryon density is not\nonly of great interest for experimental physics but also a challenge for the\ntheory. We use lattice simulations based on the canonical ensemble method to\nexplore the finite baryon density region and look for the critical point. We\nscan the phase diagram of QCD with three degenerate quark flavors using clover\nfermions with $m_\\pi \\approx 700{MeV}$ on $6^3\\times4$ lattices. We measure the\nbaryon chemical potential as we increase the density and we see the\ncharacteristic \"S-shape\" that signals the first order phase transition. We\ndetermine the phase boundary by Maxwell construction and report our preliminary\nresults for the location of critical point.",
        "positive": "Simulating gauge theories on Lefschetz thimbles: Lefschetz thimbles have been proposed recently as a possible solution to the\ncomplex action problem (sign problem) in Monte Carlo simulations. Here we\ndiscuss pure abelian gauge theory with a complex coupling $\\beta$ and apply the\nconcept of Generalized Lefschetz thimbles. We propose to simulate the theory on\nthe union of the tangential manifolds to the thimbles. We construct a local\nMetropolis-type algorithm, that is constrained to a specific tangential\nmanifold. We also discuss how, starting from this result, successive subleading\ntangential manifolds can be taken into account via a reweighting approach. We\ndemonstrate the algorithm on $U(1)$ gauge theory in 1+1 dimensions and\ninvestigate the residual sign problem."
    },
    {
        "anchor": "A Conclusive Test of Abelian Dominance Hypothesis for Topological Charge\n  in the QCD Vacuum: We study the topological feature in the QCD vacuum based on the hypothesis of\nabelian dominance. The topological charge $Q_{\\rm SU(2)}$ can be explicitly\nrepresented in terms of the monopole current in the abelian dominated system.\nTo appreciate its justification, we directly measure the corresponding\ntopological charge $Q_{\\rm Mono}$, which is reconstructed only from the\nmonopole current and the abelian component of gauge fields, by using the Monte\nCarlo simulation on SU(2) lattice. We find that there exists a one-to-one\ncorrespondence between $Q_{\\rm SU(2)}$ and $Q_{\\rm Mono}$ in the maximally\nabelian gauge. Furthermore, $Q_{\\rm Mono}$ is classified by approximately\ndiscrete values.",
        "positive": "Charmonium current-current correlators with Mobius domain-wall fermion: We calculate the charmonium correlators on the lattice with $n_f = 2+ 1$\nMoebius domain wall fermion, and extract the charm quark mass and the strong\ncoupling constant. Time moments are defined by current-current correlators,\nwhich have been calculated in the continuum theory by perturbation theory. We\nextract the charm quark mass by matching the lattice results with the\ncorresponding perturbative QCD calculations, using the recently generated\nensembles by the JLQCD collaboration at lattice spacings $a = 0.083, 0.055$,\nand $0.044$ fm."
    },
    {
        "anchor": "Understanding Parton Distributions from Lattice QCD: Present Limitations\n  and Future Promise: This talk will explain how ground state matrix elements specifying moments of\nquark density and spin distributions in the nucleon have been calculated in\nfull QCD, show how physical extrapolation to the chiral limit including the\nphysics of the pion cloud resolves previous apparent conflicts with experiment,\nand describe the computational resources required for a definitive comparison\nwith experiment.",
        "positive": "Low-energy constants in the chiral Lagrangian with baryon octet and\n  decuplet fields from Lattice QCD data on CLS ensembles: We perform an analysis of Lattice QCD data on baryon octet and decuplet\nmasses based on the chiral SU(3) Lagrangian. Low-energy constants (LEC) are\nadjusted to describe baryon masses from a large set of CLS ensembles, where\nfinite-box and discretization effects are considered. The set is successfully\ncompared against previous Lattice QCD data from ensembles generated with\ndistinct QCD actions by the ETMC, QCDSF-UKQCD and HSC groups. Discretization\neffects are modelled by the use of action and lattice-scale dependent leading\norders LEC, where uniform values are imposed in the limit of vanishing lattice\nscales. From the CLS data set we extract a pion-nucleon sigma term,\n$\\sigma_{\\pi N}= 58.7(1.2)$ MeV, compatible with its empirical value and a\nsizeable strangeness content of the nucleon with $\\sigma_{sN} = -316(76)$ MeV."
    },
    {
        "anchor": "MC simulations of $O(2)\u03c6^4$ theory in three dimensions with worm\n  algorithm: We study the critical region of the $O(2)\\,\\phi^4$ theory by means of Monte\nCarlo simulations on the lattice. In particular we determine the ratio\n$\\Delta\\langle\\phi^2\\rangle_c/g$ in order to estimate the first correction to\nthe critical temperature of a weak interacting Bose gas.",
        "positive": "The axial anomaly in lattice QED. A universal point of view: We give a perturbative proof that U(1) lattice gauge theories generate the\naxial anomaly in the continuum limit under very general conditions on the\nlattice Dirac operator. These conditions are locality, gauge covariance and the\nabsense of species doubling. They hold for Wilson fermions as well as for\nrealizations of the Dirac operator that satisfy the Ginsparg-Wilson relation.\nThe proof is based on the lattice power counting theorem."
    },
    {
        "anchor": "The Chiral Separation Effect from lattice QCD at the physical point: In this paper we study the Chiral Separation Effect by means of\nfirst-principles lattice QCD simulations. For the first time in the literature,\nwe determine the continuum limit of the associated conductivity using 2+1\nflavors of dynamical staggered quarks at physical masses. The results reveal a\nsuppression of the conductivity in the confined phase and a gradual enhancement\ntoward the perturbative value for high temperatures. In addition to our\ndynamical setup, we also investigate the impact of the quenched approximation\non the conductivity, using both staggered and Wilson quarks. Finally, we\nhighlight the relevance of employing conserved vector and anomalous axial\ncurrents in the lattice simulations.",
        "positive": "Overlap Quark Propagator in Coulomb Gauge QCD and the Interrelation of\n  Confinement and Chiral Symmetry Breaking: The chirally symmetric overlap quark propagator is explored in Coulomb gauge\nfor the first time. This gauge is especially well suited for studying the\ninterrelation between confinement and chiral symmetry breaking, since\nconfinement can be attributed to the infrared divergence of the vector dressing\nfunction of the inverse quark propagator. Using quenched gauge field\nconfigurations on a $20^4$ lattice, the dressing functions of the quark\npropagator as well as the dynamical quark mass function are evaluated, also in\nthe chiral limit. Chiral symmetry is artificially restored by removing the low\nmode contribution from the quark propagator. After removing enough low-lying\nmodes, the dynamical quark mass function approaches the current quark mass in\nthe whole momentum region and goes to zero in the chiral limit. However, the\nvector dressing function is unaffected by the low-mode removal. It follows that\nthe quark energy dispersion is still infrared divergent and quarks in such a\nchiral symmetry restored phase are still confined within a hadron."
    },
    {
        "anchor": "String effects and the distribution of the glue in mesons at finite\n  temperature: The distribution of the gluon action density in mesonic systems is\ninvestigated at finite temperature. The simulations are performed in quenched\nQCD for two temperatures below the deconfinment phase. Unlike the gluonic\nprofiles displayed at T=0, the action density iso-surfaces display a\nprolate-spheroid like shape. The curved width profile of the flux-tube is found\nto be consistent with the prediction of the free Bosonic string model at large\ndistances.",
        "positive": "New approach to lattice QCD at finite density: reweighting without an\n  overlap problem: Approaches to finite baryon density lattice QCD usually suffer from\nuncontrolled systematic uncertainties in addition to the well-known sign\nproblem. We test a method - sign reweighting - that works directly at finite\nchemical potential and is yet free from any such uncontrolled systematics: with\nthis approach the only problem is the sign problem itself. In practice the\napproach involves the generation of configurations with the positive fermionic\nweights given by the absolute value of the real part of the quark determinant,\nand a reweighting by a sign. There are only two sectors, +1 and -1 and as long\nas the average $\\left\\langle \\pm \\right\\rangle \\neq 0$ (with respect to the\npositive weight) this discrete reweighting has no overlap problem - unlike\nreweighting from $\\mu=0$ - and the results are reliable. We also present\nresults based on this algorithm on the phase diagram of lattice QCD with two\ndifferent actions: as a first test, we apply the method to calculate the\nposition of the critical endpoint with unimproved staggered fermions at\n$N_\\tau=4$; as a second application, we study the phase diagram with 2stout\nimproved staggered fermions at $N_\\tau=6$. This second one is already a\nreasonably fine lattice - relevant for phenomenology. We demonstrate that the\nmethod penetrates the region of the phase diagram where the Taylor and\nimaginary chemical potential methods lose predictive power."
    },
    {
        "anchor": "Baryonic or quarkyonic matter?: During the last years it has become possible to address the cold and dense\nregime of QCD directly for sufficiently heavy quarks, where combined strong\ncoupling and hopping expansions are convergent and a 3d effective theory can be\nderived, which allows to control the sign problem either in simulations or by\nfully analytic calculations. In this contribution we review the effective\ntheory and study the $N_c$-dependence of the nuclear liquid gas transition, as\nwell as the equation of state of baryonic matter in the strong coupling limit.\nWe find the transition to become more strongly first order with growing $N_c$,\nsuggesting that in the large $N_c$ limit its critical endpoint moves to high\ntemperatures to connect with the deconfinement transition. Furthermore, to\nleading and next-to-leading order in the strong coupling and hopping\nexpansions, respectively, the pressure is found to scale as $p\\sim N_c$. This\nsuggests that baryonic and quarkyonic matter might be the same at nuclear\ndensities. Further work is needed to see whether this result is stable under\ngauge corrections.",
        "positive": "On Some Features of Color Confinement: It is argued that a dual symmetry is needed to naturally explain experimental\nlimits on color confinement. Since color is an exact symmetry the only\npossibility is that this symmetry be a dual symmetry, related to non trivial\nspatial homotopy. The sphere at infinity of 3-dimensional space being\n2-dimensional, the relevant homotopy is $\\Pi_2$, the corresponding\nconfigurations monopoles, and the mechanism dual superconductivity. The\nconsistency of the order-disorder nature of the deconfining transition is\ncompared with lattice data . It is also shown that the only dual quantum number\nis magnetic charge and the key quantity is 't Hooft tensor, independent of the\ngauge group. The general form of the 't Hooft tensor is computed."
    },
    {
        "anchor": "Lattice QCD results at finite T and \u03bc: We propose a method to study lattice QCD at finite temperature (T) and\nchemical potential (\\mu). We test the method and compare it with the Glasgow\nmethod using n_f=4 staggered QCD with imaginary \\mu. The critical endpoint (E)\nof QCD on the Re(\\mu)-T plane is located. We use n_f=2+1 dynamical staggered\nquarks with semi-realistic masses on L_t=4 lattices. Our results are based on\n{\\cal{O}}(10^3-10^4) configurations.",
        "positive": "The hyperon spectrum from lattice QCD: Hyperon decays present a promising alternative for extracting $\\vert V_{us}\n\\vert$ from lattice QCD combined with experimental measurements. Currently\n$\\vert V_{us} \\vert$ is determined from the kaon decay widths and a lattice\ncalculation of the associated form factor. In this proceeding, I will present\npreliminary work on a lattice determination of the hyperon mass spectrum. I\nwill additionally summarize future goals in which we will calculate the hyperon\ntransition matrix elements, which will provide an alternative means for\naccessing $\\vert V_{us} \\vert$. This work is based on a particular formulation\nof SU(2) chiral perturbation theory for hyperons; determining the extent to\nwhich this effective field theory converges is instrumental in understanding\nthe limits of its predictive power, especially since some hyperonic observables\nare difficult to calculate near the physical pion mass (e.g.,\nhyperon-to-nucleon form factors), and thus the use of heavier than physical\npion masses is likely to yield more precise results when combined with\nextrapolations to the physical point.}"
    },
    {
        "anchor": "Staggered Chiral Perturbation Theory for All-Staggered Heavy-Light\n  Mesons: In HISQ simulations by the MILC and Fermilab Lattice collaborations, both the\nlight quarks and the charm quark are staggered. We extend staggered chiral\nperturbation theory (\\schpt) to include such all-staggered heavy-light mesons.\nWe assume that the heavy quark action is sufficiently improved that we may take\n$a m_Q <<1$ (where $m_Q$ is the heavy quark mass), but also that\n$m_Q>>\\Lambda_{QCD}$ so that a continuum heavy quark expansion is appropriate.\nUsing this \\schpt, the leptonic decay constant of the heavy-light meson is\ncalculated at next-to-leading-order. The pattern of taste splittings in the\nheavy-light meson masses is also investigated.",
        "positive": "Hamiltonian simulation of the Schwinger model at finite temperature: Using Matrix Product Operators (MPO) the Schwinger model is simulated in\nthermal equilibrium. The variational manifold of gauge invariant MPO is\nconstructed to represent Gibbs states. As a first application the chiral\ncondensate in thermal equilibrium is computed and agreement with earlier\nstudies is found. Furthermore, as a new application the Schwinger model is\nprobed with a fractional charged static quark-antiquark pair separated\ninfinitely far from each other. A critical temperature beyond which the string\ntension is exponentially suppressed is found, which is in qualitative agreement\nwith analytical studies in the strong coupling limit. Finally, the CT symmetry\nbreaking is investigated and our results strongly suggest that the symmetry is\nrestored at any nonzero temperature."
    },
    {
        "anchor": "Reweighting method in finite density lattice QCD: Finite density simulations require dynamical fermions which are\ncomputationally demanding. We employ Ferrenberg and Swendsen reweighting method\nto reduce the number of ensembles needed. We use their method to do a combined\nreweighting in both $\\beta$ and quark number $k$ on an ensemble generated by\nthe Kentucky group.",
        "positive": "Biased Metropolis-Heat-Bath Algorithm for Fundamental-Adjoint SU(2)\n  Lattice Gauge Theory: For SU(2) lattice gauge theory with the fundamental-adjoint action an\nefficient heat-bath algorithm is not known so that one had to rely on\nMetropolis simulations supplemented by overrelaxation. Implementing a novel\nbiased Metropolis-heat-bath algorithm for this model, we find improvement\nfactors in the range 1.45 to 2.06 over conventionally optimized Metropolis\nsimulations. If one optimizes further with respect to additional overrelaxation\nsweeps, the improvement factors are found in the range 1.3 to 1.8."
    },
    {
        "anchor": "Flavor decomposition for the proton helicity parton distribution\n  functions: We present, for the first time, an \\textit{ab initio} calculation of the\nindividual up, down and strange quark helicity parton distribution functions\nfor the proton. The calculation is performed within the twisted mass\nclover-improved fermion formulation of lattice QCD using one ensemble of\ndynamical up, down, strange and charm quarks with a pion mass of 260 MeV. The\nlattice matrix elements are non-perturbatively renormalized and the final\nresults are presented in the $\\overline{ \\rm MS}$ scheme at a scale of 2 GeV.\nWe give results on the $\\Delta u^+(x)$ and $\\Delta d^+(x)$, including\ndisconnected quark loop contributions, as well as on the $\\Delta s^+(x)$. For\nthe latter we achieve unprecedented precision compared to the phenomenological\nestimates.",
        "positive": "Scalar lattice gauge theory: Scalar lattice gauge theories are models for scalar fields with local gauge\nsymmetries. No fundamental gauge fields, or link variables in a lattice\nregularization, are introduced. The latter rather emerge as collective\nexcitations composed from scalars. For suitable parameters scalar lattice gauge\ntheories lead to confinement, with all continuum observables identical to usual\nlattice gauge theories. These models or their fermionic counterpart may be\nhelpful for a realization of gauge theories by ultracold atoms. We conclude\nthat the gauge bosons of the standard model of particle physics can arise as\ncollective fields within models formulated for other \"fundamental\" degrees of\nfreedom."
    },
    {
        "anchor": "Precision charm physics, m_c and alpha_s from lattice QCD: We present an update of results from the HPQCD collaboration on charm physics\nusing the Highly Improved Staggered Quark action. This includes a precise\ndetermination of m_c using moments of current-current correlators combined with\nhigh-order continuum QCD perturbation theory. We also include an update on the\ndetermination of alpha_s from lattice QCD, preliminary results on the\ndetermination of m_b and a summary plot of the status of the gold-plated meson\nspectrum. There is an appendix on tackling systematic errors in fitting using\nthe Bayesian approach.",
        "positive": "A subset solution to the sign problem in random matrix simulations: We present a solution to the sign problem in dynamical random matrix\nsimulations of a two-matrix model at nonzero chemical potential. The sign\nproblem, caused by the complex fermion determinants, is solved by gathering the\nmatrices into subsets, whose sums of determinants are real and positive even\nthough their cardinality only grows linearly with the matrix size. A detailed\nproof of this positivity theorem is given for an arbitrary number of fermion\nflavors. We performed importance sampling Monte Carlo simulations to compute\nthe chiral condensate and the quark number density for varying chemical\npotential and volume. The statistical errors on the results only show a mild\ndependence on the matrix size and chemical potential, which confirms the\nabsence of sign problem in the subset method. This strongly contrasts with the\nexponential growth of the statistical error in standard reweighting methods,\nwhich was also analyzed quantitatively using the subset method. Finally, we\nshow how the method elegantly resolves the Silver Blaze puzzle in the\nmicroscopic limit of the matrix model, where it is equivalent to QCD."
    },
    {
        "anchor": "Spectral sum of current correlators from lattice QCD: We propose a method to use lattice QCD to compute the Borel transform of the\nvacuum polarization function appearing in the Shifman-Vainshtein-Zakharov QCD\nsum rule. We construct the spectral sum corresponding to the Borel transform\nfrom two-point functions computed on the Euclidean lattice. As a proof of\nprinciple, we compute the $s \\bar{s}$ correlators at three lattice spacings and\ntake the continuum limit. We confirm that the method yields results that are\nconsistent with the operator product expansion in the large Borel mass region.\nThe method provides a ground on which the OPE analyses can be directly compared\nwith nonperturbative lattice computations.",
        "positive": "Mass anomalous dimension in sextet QCD: We extend our previous study of the SU(3) gauge theory with N_f=2 flavors of\nfermions in the sextet representation of color. Our tool is the Schroedinger\nfunctional method. By changing the lattice action, we push the bulk transition\nof the lattice theory to stronger couplings and thus reveal the beta function\nand the mass anomalous dimension gamma_m over a wider range of coupling, out to\ng^2 ~ 11. Our results are consistent with an infrared fixed point, but walking\nis not ruled out. Our main result is that gamma_m never exceeds 0.45, making\nthe model unsuitable for walking technicolor. We use a novel method of\nextrapolation to the large-volume/continuum limit, tailored to near-conformal\ntheories."
    },
    {
        "anchor": "Non-perturbative Test of the Witten-Veneziano Formula from Lattice QCD: We compute both sides of the Witten-Veneziano formula using lattice\ntechniques. For the one side we perform dedicated quenched simulations and use\nthe spectral projector method to determine the topological susceptibility in\nthe pure Yang-Mills theory. The other side we determine in lattice QCD with\n$N_f=2+1+1$ dynamical Wilson twisted mass fermions including for the first time\nalso the flavour singlet decay constant. The Witten-Veneziano formula\nrepresents a leading order expression in the framework of chiral perturbation\ntheory and we also employ leading order chiral perturbation theory to relate\nthe flavor singlet decay constant to the relevant decay constant parameters in\nthe quark flavor basis and flavor non-singlet decay constants. After taking the\ncontinuum and the SU$(2)$ chiral limits we compare both sides and find good\nagreement within uncertainties.",
        "positive": "Asymmetry Parameter Role in Description of Phase Structure of Lattice\n  Gluodynamics at Finite Temperature: The role of lattice asymmetry parameter in description of the SU(2)\ngluodynamics phase structure at finite temperature is studied analytically. The\nfact that renormalization group relations which permit to remove the lattice\nasymmetry parameter from the thermodynamical quantities in the \"naive\" limit\ndon't do the same in the approximation SU(N) = Z(N) keeping the \"naive\" limit\nresults at the same time was point out. An additional condition which would fix\nasymmetry parameter is needed for this dependence removal."
    },
    {
        "anchor": "String Breaking in Lattice Quantum Chromodynamics: The separation of a heavy quark and antiquark pair leads to the formation of\na tube of flux, or string, which should break in the presence of light\nquark-antiquark pairs. This expected zero temperature phenomenon has proven\nelusive in simulations of lattice QCD. We present simulation results that show\nthat the string does break in the confining phase at nonzero temperature.",
        "positive": "Hints and challenges in heavy flavor physics: Heavy flavor physics entered a new era when the Belle II experiment observed\nits first collision. There are several hints found so far by BaBar, Belle, and\nLHCb in particular, that suggest the physics beyond the Standard Model\nappearing in the loop processes at short distances. They will be further tested\nby higher precision experiments in the coming years, while the role of lattice\nQCD is to understand the long-distance physics quantitatively so that one can\nunambiguously isolate the short-distance physics from the experimental data. I\nsummarize the status towards this goal and then look at the challenges we are\nfacing."
    },
    {
        "anchor": "Parton Distributions from Lattice QCD with Momentum Smearing: In this work we continue our effort to explore a recent proposal, which\nallows light-cone distributions to be extracted from purely spatial\ncorrelations, being thus accessible to lattice methods. In order to test the\nfeasibility of this method, we present our latest results from a twisted mass\nlattice calculation of the flavor non-singlet momentum, helicity and\ntransversity distributions of the nucleon. Furthermore, we apply a newly\nproposed momentum improved smearing, which has the potential to reach higher\nnucleon momenta as required for a safe matching procedure to the physical\ndistribution functions.",
        "positive": "Finite volume effects in the gluon propagator: We report on a preliminary study of the volume dependence of the gluon\npropagator. The propagator is computed using different lattice volumes, its\nextrapolation to infinite volume is investigated with particular attention to\nthe its IR behaviour. Our data shows a mild but measurable dependence with the\nvolume. Unfortunately, we are not able yet to clarify its behaviour close to\nzero momentum."
    },
    {
        "anchor": "Recent results on large N gauge theories on a single site lattice with\n  adjoint fermions: Large N gauge theories with adjoint matter can be numerically studied using\nlattice techniques. Eguchi-Kawai reductions holds for this theory and one can\nreduce the lattice model to a single site. Hybrid Monte Carlo algorithm can be\nused to simulate this model. One can either perform an exact computation of the\n\"fermionic force\" or use pseudo fermions as part of the HMC algorithm. The\nformer algorithm is slower than the latter but has the advantage that one can\nwork with any real number for the fermion flavor. Some results using both\nalgorithms will be presented.",
        "positive": "High-Performance I/O: HDF5 for Lattice QCD: Practitioners of lattice QCD/QFT have been some of the primary pioneer users\nof the state-of-the-art high-performance-computing systems, and contribute\ntowards the stress tests of such new machines as soon as they become available.\nAs with all aspects of high-performance-computing, I/O is becoming an\nincreasingly specialized component of these systems. In order to take advantage\nof the latest available high-performance I/O infrastructure, to ensure\nreliability and backwards compatibility of data files, and to help unify the\ndata structures used in lattice codes, we have incorporated parallel HDF5 I/O\ninto the SciDAC supported USQCD software stack. Here we present the design and\nimplementation of this I/O framework. Our HDF5 implementation outperforms\noptimized QIO at the 10-20% level and leaves room for further improvement by\nutilizing appropriate dataset chunking."
    },
    {
        "anchor": "Nucleon mass and isovector couplings in 2+1-flavor dynamical domain-wall\n  lattice QCD near physical mass: We report nucleon mass, isovector vector and axial-vector charges, and tensor\nand scalar couplings, calculated using two recent 2+1-flavor dynamical\ndomain-wall fermions lattice-QCD ensembles generated jointly by the\nRIKEN-BNL-Columbia and UKQCD collaborations. These ensembles were generated\nwith Iwasaki $\\times$ dislocation-suppressing-determinant-ratio gauge action at\ninverse lattice spacing of 1.378(7) GeV and pion mass values of 249.4(3) and\n172.3(3) MeV. The nucleon mass extrapolates to a value $m_N = 0.950(5)$ GeV at\nphysical point. The isovector vector charge renormalizes to unity in the chiral\nlimit, narrowly constraining excited-state contamination in the calculation.\nThe ratio of the isovector axial-vector to vector charges shows a deficit of\nabout ten percent. The tensor coupling no longer depends on mass and\nextrapolates to 1.04(5) in $\\overline {\\rm MS}$ 2-GeV renormalization at\nphysical point, in a good agreement with the value obtained at the lightest\nmass in our previous calculations and other calculations that followed. The\nscalar charge, though noisier, does not show mass dependence and is in\nagreement with other calculations.",
        "positive": "Uses of Effective Field Theory in Lattice QCD: Several physical problems in particle physics, nuclear physics, and\nastrophysics require information from non-perturbative QCD to gain a full\nunderstanding. In some cases the most reliable technique for quantitative\nresults is to carry out large-scale numerical calculations in lattice gauge\ntheory. As in any numerical technique, there are several sources of\nuncertainty. This chapter explains how effective field theories are used to\nkeep them under control and, then, obtain a sensible error bar. After a short\nsurvey of the numerical technique, we explain why effective field theories are\nnecessary and useful. Then four important cases are reviewed: Symanzik's\neffective field theory of lattice spacing effects; heavy-quark effective theory\nas a tool for controlling discretization effects of heavy quarks; chiral\nperturbation theory as a tool for reaching the chiral limit; and a general\nfield theory of hadrons for deriving finite volume corrections."
    },
    {
        "anchor": "Confinement in the lattice Landau Gauge QCD simulation: The running coupling and the Kugo-Ojima parameter of the confinement\ncriterion are measured for the quenched SU(3) \\beta=6.4, 6.45, 56^4 lattice and\nthe unquenched \\beta=5.2, 20^3 x 48 lattice of JLQCD, \\beta=2.1, \\kappa=0.1357,\n0.1382, 24^3 x 48 lattice of CP-PACS and \\beta_{imp}=6.76,a m_{u,d}=0.007,\n6.83,a m_{u,d}=0.040, 20^3 x 64 lattice of MILC collaboration.\n  The quenched SU(3) 56^4 lattice data suggest presence of infrared fixed point\nof \\alpha_s=2.5(5) and the approach of the ensemble of the 1st copy to the\nGribov boundary. The running coupling of q>2GeV can be fitted by the\nperturbative QCD(pQCD) + c/q^2 correction. We find the Kugo-Ojima parameter\nu(0)=-0.83(3).\n  The rotational symmetry of the gluon propagator of the unquenched SU(3) is\npartially recovered, but its magnitude depends on whether the Wilson fermion or\nthe Kogut-Susskind(KS) fermion are coupled to the gauge field. The gluon\npropagator coupled to KS fermion is more suppressed than that coupled to Wilson\nfermion. The running coupling inherits the same trend. The unquenched running\ncoupling of the of q>3GeV can be fitted by the pQCD without c/q^2 term. The\nKugo-Ojima parameter of unquenched configurations with light fermion masses is\nconsistent with u(0)=-1.0.",
        "positive": "Three-particle quantization condition: an update: We give an update on our derivation of a quantization condition relating the\nfinite-volume spectrum of three particles in a cubic box to infinite-volume\nscattering quantities. We have discovered and fixed technical problems in the\nderivation sketched in the proceedings of last year's lattice conference\n[arXiv:1311.4848], and have presented a detailed description of the corrected\nderivation in Ref. [arXiv:1408.5933]. Here we give an overview of the problems\nand their solutions, and describe open questions."
    },
    {
        "anchor": "Correlation Length From Cluster-Diameter Distribution: We report numerical estimates of correlation lengths in 2D Potts models from\nthe asymptotic decay of the cluster-diameter distribution. Using this\nobservable we are able to verify theoretical predictions for the correlation\nlength in the disordered phase at the transition point for $q=10$, 15, and 20\nwith an accuracy of about $1%-2%$. This is a considerable improvement over\nprevious measurements using the standard (projected) two-point function.",
        "positive": "$\\mathcal{N}=1$ Supersymmetric $SU(3)$ Gauge Theory -- Pure Gauge sector\n  with a twist: Supersymmetric gauge theories are an essential part of most theories beyond\nthe standard model. In the present work we investigate the pure gauge sector of\nSuper-QCD focusing on the bound states, i.e. mesonic gluinoballs,\ngluino-glueballs and pure glueballs. To improve chiral properties and to\nminimize breaking of supersymmetry at finite lattice spacing, we introduce a\ndeformed Super-Yang-Mills lattice action. It contains a twist term, similar to\nthe twisted-mass formulation of lattice QCD. We furthermore explore if the\nmultigrid method (DD$\\alpha$AMG solver) applied to the gluinos (adjoint\nMajorana fermions) achieves similar improvements as in QCD."
    },
    {
        "anchor": "The lattice Schwinger model as a discrete sum of filled Wilson loops: Using techniques from hopping expansion we identically map the lattice\nSchwinger model with Wilson fermions to a model of oriented loops on the\nlattice. This is done by first computing the explicit form of the fermion\ndeterminant in the external field. Subsequent integration of the gauge fields\nrenders a sum over all loop configurations with simple Gaussian weights\ndepending on the number of plaquettes enclosed by the loops. In our new\nrepresentation vacuum expectation values of local fermionic operators (scalars,\nvectors) can be computed by simply counting the loop flow through the sites\n(links) supporting the scalars (vectors). The strong coupling limit, possible\napplications of our methods to 4-D models and the introduction of a chemical\npotential are discussed.",
        "positive": "On one-loop corrections to matching conditions of Lattice HQET including\n  1/m_b terms: HQET is an effective theory for QCD with N_f light quarks and a massive\nvalence quark if the mass of the latter is much bigger than Lambda_QCD. As any\neffective theory, HQET is predictive only when a set of parameters has been\ndetermined through a process called matching. The non-perturbative matching\nprocedure including 1/m_b terms, developped by the ALPHA collaboration,\nconsists of 19 carefully chosen observables which are precisely computable in\nlattice QCD as well as in lattice HQET. The matching conditions are then a set\nof 19 equations which relate the QCD and HQET values of these observables. We\npresent a study of one-loop corrections to two generic matching observables\ninvolving correlation function with an insertion of the A_0 operator. Our\nresults enable us to quantify the quality of the relevant observables in view\nof the envisaged non-perturbative implementation of this matching procedure."
    },
    {
        "anchor": "Topological susceptibility in QCD with two flavors and 3-5 colors -- a\n  pilot study: I present a calculation of the topological susceptibility $\\chi_T$ in\n$SU(N_c)$ gauge theory with $N_c=3-5$ colors and $N_f=2$ degenerate flavors of\nfermions. The results lie on a common curve when expressed in terms of the\ncombination $N_c m_{PS}^2 t_0$ where $m_{PS}$ is the pseudoscalar meson mass\nand $t_0$ is the flow parameter. $\\chi_T$ approaches its quenched value as the\npseudoscalar mass becomes large. The lattice simulations use clover fermions.\nThey are done at a single lattice spacing, roughly matched across $N_c$, and\nover a restricted range of fermion masses.",
        "positive": "New insights on proton structure from lattice QCD: the twist-3 parton\n  distribution function $g_T(x)$: In this work, we present the first-ever calculation of the isovector flavor\ncombination of the twist-3 parton distribution function $g_T(x)$ for the proton\nfrom lattice QCD. We use an ensemble of gauge configurations with two\ndegenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally\ntwisted mass fermions with a clover improvement. The lattice has a spatial\nextent of 3~fm, lattice spacing of 0.093~fm, and reproduces a pion mass of\n$260$ MeV. We use the quasi-distribution approach and employ three values of\nthe proton momentum boost, 0.83 GeV, 1.25 GeV, and 1.67 GeV. We use a\nsource-sink separation of 1.12~fm to suppress excited-states contamination. The\nlattice data are renormalized non-perturbatively. We calculate the matching\nequation within Large Momentum Effective Theory, which is applied to the\nlattice data in order to obtain $g_T$. The final distribution is presented in\nthe $\\overline{\\rm MS}$ scheme at a scale of 2 GeV. We also calculate the\nhelicity distribution $g_1$ to test the Wandzura-Wilczek approximation for\n$g_T$. We find that the approximation works well for a broad range of $x$. This\nwork demonstrates the feasibility of accessing twist-3 parton distribution\nfunctions from novel methods within lattice QCD and can provide essential\ninsights into the structure of hadrons."
    },
    {
        "anchor": "Deconfinement transition at weak coupling in Yang-Mills theory on a\n  torus: We describe a weak coupling realization of the deconfinement transition in\ngauge theory compactified on $R^3\\times S^1$. We consider Yang-Mills theory\nwith a single Weyl fermion of mass $m$ in the adjoint representation of the\ngauge group. The fermion is subject to periodic boundary conditions,\n$\\lambda(0)=\\lambda(L)$, where $L$ is the size of the circle $S_1$. This theory\nreduces to thermal Yang-Mills theory in the limit $m\\to\\infty$. In the limit\n$m\\to 0$ the deconfinement transition can be studied using weak coupling\nmethods. The analysis is based on semi-classical objects characterized by\ntopological and magnetic charges. At leading order the relevant configurations\nare monopole-instantons and monopole-anti-monopole pairs (\"bions\"). We argue\nthat in the $m-L$ plane the weak coupling transition is continuously connected\nto the deconfinement transition in pure gauge theory.",
        "positive": "$\u03c0NN$ and Pseudoscalar Form Factors from Lattice QCD: The $\\pi NN$ form factor $g_{\\pi NN}(q^2)$ is obtained from a quenched\nlattice QCD calculation of the pseudoscalar form factor $g_P(q^2)$ of the\nproton with pion pole dominance. We find that $g_{\\pi NN}(q^2)$ fitted with the\nmonopole form agrees well with the Goldberger-Treiman relation and is much\npreferred over the dipole form. The monopole mass is determined to be $0.75 \\pm\n0.14 {\\rm GeV}$ which shows that $g_{\\pi NN}(q^2)$ is rather soft. The\nextrapolated $\\pi N$ coupling constant $g_{\\pi NN} = 12.7 \\pm 2.4$ is quite\nconsistent with the phenomenological values. We also compare $g_{\\pi NN}(q^2)$\nwith the axial form factor $g_A(q^2)$ to check the pion dominance in the\ninduced pseudoscalar form factor $h_A(q^2)$ vis \\`{a} vis chiral Ward identity."
    },
    {
        "anchor": "Kernel controlled real-time Complex Langevin simulation: This study explores the utility of a kernel in complex Langevin simulations\nof quantum real-time dynamics on the Schwinger-Keldysh contour. We give several\nexamples where we use a systematic scheme to find kernels that restore correct\nconvergence of complex Langevin. The schemes combine prior information we know\nabout the system and the correctness of convergence of complex Langevin to\nconstruct a kernel. This allows us to simulate up to $1.5\\beta$ on the\nreal-time Schwinger-Keldysh contour with the 0+1 dimensional anharmonic\noscillator using $m=1$, $\\lambda=24$, which was previously unattainable using\nthe complex Langevin equation.",
        "positive": "Flavor Twisted Boundary Conditions and Isovector Form Factors: We use vector flavor symmetry to relate form factors of isospin changing\noperators to isovector form factors. Flavor twisted boundary conditions in\nlattice QCD thus allow isovector form factors of twist-two operators, e.g, to\nbe computed at continuous values of the momentum transfer. These twisted\nboundary conditions, moreover, are implemented only in the valence sector.\nEffects of the finite volume must be addressed to extract isovector moments and\nradii at zero lattice momentum. As an example, we use chiral perturbation\ntheory to assess the volume effects in extracting the isovector magnetic moment\nof the nucleon from simulations with twisted boundary conditions."
    },
    {
        "anchor": "Solving two-dimensional large-N QCD with a nonzero density of baryons\n  and arbitrary quark mass: We solve two-dimensional large-N QCD in the presence of a nonzero baryon\nnumber B, and for arbitrary quark mass m and volume L. We fully treat the\ndynamics of the gluonic zero modes and check how this affects results from\nprevious studies of the B=0 and B=1 systems. For a finite density of baryons,\nand for any m>0, we find that the ground state contains a baryon crystal with\nexpectation values for psi-bar gamma_mu psi that have a helix-like spatial\nstructure. We study how these evolve with B and see that the volume integral of\npsi-bar psi strongly changes with the baryon density. We compare this emerging\ncrystal structure with the sine-Gordon crystal, which is expected to be a good\napproximation for light quarks, and find that it is a very good approximation\nfor surprisingly heavy quarks. We also calculate the way the ground state\nenergy E changes as a function of the baryon number B, and find that for\nsufficiently large densities the function E(B) is well described by the\nequation of state for free massless quarks, thus suggesting a quark-Hadron\ncontinuity. From dE(B)/dB we calculate the quark chemical potential mu as a\nfunction of B and see that the baryons repel each other. The way mu depends on\nB also allows us to translate our findings to the grand-canonical ensemble. The\nresulting phase structure along the mu-axis contains a phase transition that\noccurs at a value of mu equal to the baryon mass divided in N, and that\nseparates a mu-independent phase with intact translation symmetry from a\nmu-dependent phase with spontaneously broken translation symmetry. Finally, our\ncalculations confirm the presence of a partial large-N Eguchi-Kawai volume\nindependence, as described in Phys.Rev.D79:105021, that arises only if one\ntreats the gluonic zero modes correctly.",
        "positive": "Nf=2+1 QCD thermodynamics with gradient flow using two-loop matching\n  coefficients: We study thermodynamic properties of Nf=2+1 QCD on the lattice adopting\nO(a)-improved Wilson quark action and Iwasaki gauge action. To cope with the\nproblems due to explicit violation of the Poincare and chiral symmetries, we\napply the Small Flow-time eXpansion (SFtX) method based on the gradient flow,\nwhich is a general method to correctly calculate any renormalized observables\non the lattice. In this method, the matching coefficients in front of operators\nin the small flow-time expansion are calculated by perturbation theory. In a\nprevious study using one-loop matching coefficients, we found that the SFtX\nmethod works well for the equation of state, chiral condensates and\nsusceptibilities. In this paper, we study the effect of two-loop matching\ncoefficients by Harlander et al. We also test the influence of the\nrenormalization scale in the SFtX method. We find that, by adopting the mu_0\nrenormalization scale of Harlander et al. instead of the conventional\nmu_d=1/sqrt{8t} scale, the linear behavior at large t is improved so that we\ncan perform the t -> 0 extrapolation of the SFtX method more confidently. In\nthe calculation of the two-loop matching coefficients by Harlander et al., the\nequation of motion for quark fields was used. For the entropy density in which\nthe equation of motion has no effects, we find that the results using the\ntwo-loop coefficients agree well with those using one-loop coefficients. On the\nother hand, for the trace anomaly which is affected by the equation of motion,\nwe find discrepancies between the one- and two-loop results at high\ntemperatures. By comparing the results of one-loop coefficients with and\nwithout using the equation of motion, the main origin of the discrepancies is\nsuggested to be attributed to O((aT)^2)=O(1/N_t^2) discretization errors in the\nequation of motion at N_t =< 10."
    },
    {
        "anchor": "Gauge potential singularities and the gluon condensate at finite\n  temperatures: The continuum limit of SU(2) lattice gauge theory is carefully investigated\nat zero and at finite temperatures. It is found that the continuum gauge field\nhas singularities originating from center degrees of freedom being discovered\nin Landau gauge. Our numerical results show that the density of these\nsingularities properly extrapolates to a non-vanishing continuum limit. The\naction density of the non-trivial Z_2 links is tentatively identified with the\ngluon condensate. We find for temperatures larger than the deconfinement\ntemperature that the thermal fluctuations of the embedded Z_2 gauge theory\nresult in an increase of the gluon condensate with increasing temperature.",
        "positive": "Investigation of the overlap of excited bottomonium states with hybrid\n  operators: We analyze the overlap of color-octet meson operators with the $\\Upsilon$ and\nthe $\\eta_b$ and their excited states, especially the first radial excitations.\nOur analysis is based on NRQCD and includes all terms up to order $v^4$. We use\na variety of source and sink operators as a basis for the variational method,\nwhich enables us to clearly separate the mass eigenstates and hence to extract\nthe desired amplitudes. The results show the usefulness of the variational\nmethod for determining couplings to excited hadronic states."
    },
    {
        "anchor": "Running mass, effective energy and confinement: the lattice quark\n  propagator in Coulomb gauge: We calculate the lattice quark propagator in Coulomb gauge both from\ndynamical and quenched configurations. We show that in the continuum limit both\nthe static and full quark propagator are multiplicatively renormalizable. From\nthe propagator we extract the quark renormalization function Z(|p|) and the\nrunning mass M(|p|) and extrapolate the latter to the chiral limit. We find\nthat M(|p|) practically coincides with the corresponding Landau gauge function\nfor small momenta. The computation of M(|p|) can be however made more efficient\nin Coulomb gauge; this can lead to a better determination of the chiral mass\nand the quark anomalous dimension. Moreover from the structure of the full\npropagator we can read off an expression for the dispersion relation of quarks,\ncompatible with an IR divergent effective energy. If confirmed on larger\nvolumes this finding would allow to extend the Gribov-Zwanziger confinement\nmechanism to the fermionic sector of QCD.",
        "positive": "Lattice studies of Sp(2N) gauge theories using GRID: Four-dimensional gauge theories based on symplectic Lie groups provide\nelegant realisations of the microscopic origin of several new physics models.\nNumerical studies pursued on the lattice provide quantitative information\nnecessary for phenomenological applications. To this purpose, we implemented\nSp(2N) gauge theories using Monte Carlo techniques within Grid, a performant\nframework designed for the numerical study of quantum field theories on the\nlattice. We show the first results obtained using this library, focusing on the\ncase-study provided by the Sp(4) theory coupled to Nas = 4 Wilson-Dirac\nfermions transforming in the 2-index antisymmetric representation. In\nparticular, we discuss preliminary tests of the algorithm and we test some of\nits main functionalities."
    },
    {
        "anchor": "The static quark potential in 2+1 flavour Domain Wall QCD from QCDOC: We report our present status of on-going project on the measurement of the\nstatic quark potential in 2+1 flavour domain wall QCD with various improved\ngauge actions and couplings. Lattice spacing determined from Sommer scale on\nthese ensembles are from 1.6 GeV to 2.0 GeV for $16^3 \\times 32$ lattice with\nfifth dimension size 8. We also examine size of discretization error from\nscaling of a pair of dimensionless quantities, $(r_0 m_\\pi)^2$ and $r_0\nm_\\rho$, and found small scaling violation.",
        "positive": "The Phase Diagram of Fluid Random Surfaces with Extrinsic Curvature: We present the results of a large-scale simulation of a Dynamically\nTriangulated Random Surface with extrinsic curvature embedded in\nthree-dimensional flat space. We measure a variety of local observables and use\na finite size scaling analysis to characterize as much as possible the regime\nof crossover from crumpled to smooth surfaces."
    },
    {
        "anchor": "A Wilson-Majorana Regularization for Lattice Chiral Gauge Theories: We discuss the regularization of chiral gauge theories on the lattice\nintroducing only physical degrees of freedom. This is obtained by writing the\nWilson term in a Majorana form, at the expense of the U(1) symmetry related to\nfermion number conservation. The idea of restoring chiral invariance in the\ncontinuum by introducing a properly chosen set of counterterms to be added to\nthe tree level action is checked against one-loop perturbative calculations.",
        "positive": "Quantum gauge fixing and vortex dominance: We introduce quantum gauge fixing (QGF) as a new class of gauge fixings.\nWhile the maximal center gauge might not show vortex dominance, the confining\nproperties of the vortices observed in past lattice calculations are argued to\nhave been obtained in a gauge more akin to QGF than to the strict maximal\ncenter gauge."
    },
    {
        "anchor": "Lattice Field Theory Methods in Modern Biophysics: An effective field theory exists describing a very large class of\nbiophysically interesting Coulomb gas systems: the lowest order (mean-field)\nversion of this theory takes the form of a generalized Poisson-Boltzmann\ntheory. Interaction terms depend on details (finite-size effects, multipole\nproperties, etc). Convergence of the loop expansion holds only if mutual\ninteractions of mobile charges are small compared to their interaction with the\nfixed-charge environment, which is frequently not the case. Problems with the\nstrongly- coupled effective theory can be circumvented with an alternative\nlocal lattice formulation, with real positive action. In realistic situations,\nwith variable dielectric, a determinant of the Poisson operator must be\ninserted to generate correct electrostatics. Methods adopted from unquenched\nlattice QCD do this very efficiently.",
        "positive": "Simulating 2+1d $\\mathbb{Z}_3$ lattice gauge theory with iPEPS: We simulate a zero-temperature pure $\\mathbb{Z}_3$ Lattice Gauge Theory in\n2+1 dimensions by using an iPEPS (Infinite Projected Entangled-Pair State)\nansatz for the ground state. Our results are therefore directly valid in the\nthermodynamic limit. They clearly show two distinct phases separated by a phase\ntransition. We introduce an update strategy that enables plaquette terms and\nGauss-law constraints to be applied as sequences of two-body operators. This\nallows the use of the most up-to-date iPEPS algorithms. From the calculation of\nspatial Wilson loops we are able to prove the existence of a confined phase. We\nshow that with relatively low computational cost it is possible to reproduce\ncrucial features of gauge theories. We expect that the strategy allows the\nextension of iPEPS studies to more general LGTs."
    },
    {
        "anchor": "Topological Susceptibility and Zero Mode Size in Lattice QCD: We use the overlap formalism to define a topological index on the lattice. We\nstudy the spectral flow of the hermitian Wilson-Dirac operator and identify\nzero crossings with topological objects. We determine the topological\nsusceptibility and zero mode size distribution, and we comment on the stability\nof our results.",
        "positive": "High-density QCD: the effects of strangeness: I discuss the zero temperature phase diagram of QCD, as a function of baryon\ndensity and strange quark mass. The noteworthy points are that at sufficiently\nhigh density chiral symmetry is always restored, and at low strange quark mass\nthere need be no phase transition between nuclear matter and quark matter. I\ncomment on the possibility that introducing a strange quark may make it easier\nto see finite-density physics on the lattice."
    },
    {
        "anchor": "Running coupling constant and propagators in SU(2) Landau gauge: We present a numerical study of the running coupling constant and of the\ngluon and ghost propagators in minimal Landau gauge. Simulations are done in\npure SU(2) lattice gauge theory for several values of beta and lattice sizes.\nWe use two different lattice setups.",
        "positive": "Finite Element Analysis of the Schroedinger Equation: The purpose of this work is to test the application of the finite element\nmethod to quantum mechanical problems, in particular for solving the\nSchroedinger equation.\n  We begin with an overview of quantum mechanics, and standard numerical\ntechniques. We then give an introduction to finite element analysis using the\ndiffusion equation as an example. Three numerical time evolution methods are\nconsidered: the (tried and tested) Crank-Nicolson method, the continuous\nspace-time method, and the discontinuous space-time method."
    },
    {
        "anchor": "Unpolarized Transverse-Momentum-Dependent Parton Distributions of the\n  Nucleon from Lattice QCD: We present a first calculation of the unpolarized proton's isovector\ntransverse-momentum-dependent parton distribution functions (TMDPDFs) from\nlattice QCD, which are essential to predict observables of multi-scale,\nsemi-inclusive processes in the standard model. We use a $N_f=2+1+1$ MILC\nensemble with valence clover fermions on a highly improved staggered quark sea\n(HISQ) to compute the quark momentum distributions in large-momentum protons on\nthe lattice. The state-of-the-art techniques in renormalization and\nextrapolation in correlation distance on the lattice are adopted. The one-loop\ncontributions in the perturbative matching kernel to the light-cone TMDPDFs are\ntaken into account, and the dependence on the pion mass and hadron momentum is\nexplored. Our results are qualitatively comparable with phenomenological\nTMDPDFs, which provide an opportunity to predict high energy scatterings from\nthe first principles.",
        "positive": "Light hadron spectrum using an O(a)-improved Wilson action with two\n  dynamical quark flavours: I present results of recent work for the UKQCD Collaboration on the light\nhadron spectrum using a non-perturbatively O(a)-improved Wilson action with two\ndegenerate flavours of dynamical quarks on a 16^3x32 lattice. Values of the\nbare gauge coupling and bare dynamical quark mass were chosen to keep the\nlattice spacing fixed at two distinct values in physical units as determined\nthrough the Sommer scale parameter, r0. I also include results for a quenched\nensemble with a lattice spacing matching one of these dynamical sets and\nresults from an exploratory run at lighter bare quark mass."
    },
    {
        "anchor": "Continuum extrapolation of $B_K$ with staggered fermions: We report on recent progress in the calculation of $B_K$ using HYP-smeared\nstaggered fermions on the MILC asqtad lattices.\n  Our main focus is on the continuum extrapolation, which is done using (up to)\nfour different lattice spacings---$a\\approx$ 0.12, 0.09, 0.06 and 0.045 fm.\nSince Lattice 2010, we have reduced the statistical errors on the $a\\approx\n0.09\\;$fm lattices by a factor of $\\sim 3$, and roughly doubled the size of the\n$a\\approx0.045\\;$fm ensemble.\n  We find that these improvements have a very significant impact on the\ncontinuum extrapolation, with the $a\\approx 0.12\\;$fm data lying outside the\nrange of applicability of simple functional forms. Hence we use only the three\nsmallest lattice spacings to perform the extrapolation, finding $\\hat{B}_K =\nB_K(\\text{RGI}) = 0.725 \\pm 0.004(\\text{stat}) \\pm 0.038(\\text{sys}) $. This\nvalue is consistent with our published value from 2010 (based the three\ncoarsest lattice spacings), but has smaller errors.",
        "positive": "Generalised parton distributions of the pion in partially-quenched\n  chiral perturbation theory: We consider the pion matrix elements of the isoscalar and isovector\ncombinations of the vector and tensor twist-two operators that determine the\nmoments of the various pion generalised parton distributions. Our analysis is\nperformed using partially-quenched chiral perturbation theory. We work in the\nSU(2) and SU(4|2) theories and present our results at infinite volume and also\nat finite volume where some subtleties arise. These results are useful for\nextrapolations of lattice calculations of these matrix elements at small\nmomentum transfer to the physical regime."
    },
    {
        "anchor": "Polynomial Filtered HMC -- an algorithm for lattice QCD with dynamical\n  quarks: Polynomial approximations to the inverse of the fermion matrix are used to\nfilter the dynamics of the upper energy scales in HMC simulations. The use of a\nmultiple time-scale integration scheme allows the filtered pseudofermions to be\nevolved using a coarse step size. We introduce a novel generalisation of the\nnested leapfrog which allows for far greater flexibility in the choice of time\nscales. We observe a reduction in the computational expense of the molecular\ndynamics integration of between 3--5 which improves as the quark mass\ndecreases.",
        "positive": "Polyakov loop fluctuations in Dirac eigenmode expansion: We investigate correlations of the Polyakov loop fluctuations with eigenmodes\nof the lattice Dirac operator. Their analytic relations are derived on the\ntemporally odd-number size lattice with the normal non-twisted periodic\nboundary condition for the link-variables. We find that the low-lying Dirac\nmodes yield negligible contributions to the Polyakov loop fluctuations. This\nproperty is confirmed to be valid in confined and deconfined phase by numerical\nsimulations in SU(3) quenched QCD. These results indicate that there is no\ndirect, one-to-one correspondence between confinement and chiral symmetry\nbreaking in QCD in the context of different properties of the Polyakov loop\nfluctuation ratios."
    },
    {
        "anchor": "Vortex configurations in SO(3) \\times Z(2): We study the configuration space of the Tomboulis $SO(3) \\times Z(2)$\nformulation with periodic boundary conditions. The dynamical variables are\nconstrained by the required coincidence of Z(2) and SO(3) monopoles.\nFurthermore, there is an additional constraint coming from the boundary\nconditions. We propose an update algorithm that satisfies the constraints and\nis straightforward to implement.",
        "positive": "QCD on the Cell Broadband Engine: We evaluate IBM's Enhanced Cell Broadband Engine (BE) as a possible building\nblock of a new generation of lattice QCD machines. The Enhanced Cell BE will\nprovide full support of double-precision floating-point arithmetics, including\nIEEE-compliant rounding. We have developed a performance model and applied it\nto relevant lattice QCD kernels. The performance estimates are supported by\nmicro- and application-benchmarks that have been obtained on currently\navailable Cell BE-based computers, such as IBM QS20 blades and PlayStation 3.\nThe results are encouraging and show that this processor is an interesting\noption for lattice QCD applications. For a massively parallel machine on the\nbasis of the Cell BE, an application-optimized network needs to be developed."
    },
    {
        "anchor": "Chiral Susceptibilities in noncompact QED: a new determination of the\n  $\u03b3$ exponent and the critical couplings: We report the results of a measurement of susceptibilities in noncompact\n$QED_4$ in $8^4, 10^4$ and $12^4$ lattices. Due to the potentialities of the\n$MFA$ approach, we have done simulations in the chiral limit which are\ntherefore free from arbitrary mass extrapolations. Our results in the Coulomb\nphase show unambiguously that the susceptibility critical exponent $\\gamma=1$\nindependently of the flavour symmetry group. The critical couplings extracted\nfrom these calculations are in perfect agreement with previous determinations\nbased on the fermion effective action and plaquette energy, and outside the\npredictions of a logarithmically improved scalar mean field theory by eight\nstandard deviations.",
        "positive": "Perturbative spectrum of a Yukawa-Higgs model with Ginsparg-Wilson\n  fermions: A Yukawa-Higgs model with Ginsparg-Wilson (GW) fermions, proposed recently by\nBhattacharya, Martin and Poppitz as a possible lattice formulation of chiral\ngauge theories, is studied. A simple argument shows that the gauge boson always\nacquires mass by the St\\\"uckelberg (or, in a broad sense, Higgs) mechanism,\nregardless of strength of interactions. The gauge symmetry is spontaneously\nbroken. When the gauge coupling constant is small, the physical spectrum of the\nmodel consists of massless fermions, massive fermions and \\emph{massive} vector\nbosons."
    },
    {
        "anchor": "Lanczos Approach to the Inverse Square Root of a Large and Sparse Matrix: I construct a Lanczos process on a large and sparse matrix and use the\nresults of this iteration to compute the inverse square root of the same\nmatrix. The algorithm is a stable version of an earlier proposal by the author.\nIt can be used for problems related to the matrix sign and polar decomposition.\nThe application here comes from the theory of chiral fermions on the lattice.",
        "positive": "Semileptonic form factors of heavy-light mesons from lattice QCD: The form factors for the semileptonic decays of heavy-light pseudoscalar\nmesons of the type $D \\to Ke\\nu$ are studied in quenched lattice QCD at\n$\\beta=6.0$ using Wilson fermions. We explore new numerical techniques for\nimproving the signal and study $O(a)$ corrections using three different lattice\ntranscriptions of the vector current. We present a detailed discussion of the\nrelation of these lattice currents to the continuum vector current and show\nthat the disagreement between the previous results is to a large extent due to\nthe value of $Z_V$ used in the calculations. We also present results for the\ndecay constants of light-light, heavy-light and heavy-heavy mesons."
    },
    {
        "anchor": "Observation of a dynamical QCD string: Mesons constructed from the quark propagators without the lowest-lying\neigenmodes of the Dirac operator reveal not only restored SU(2)_L * SU(2)_R\nchiral and U(1)_A symmetries, but actually a higher symmetry. All possible\nchiral and U(1)_A multiplets for the states of the same spin are degenerate,\ni.e., the energy of the observed quantum levels does not depend on the spin\norientation of quarks in the system and their parities. The quark-spin\nindependence of the energy levels implies absence of the magnetic interactions\nin the system. The ultrarelativistic quark-antiquark system with only the\ncolor-electric interactions can be interpreted (or defined) as a dynamical QCD\nstring.",
        "positive": "Radiative contribution to the effective potential in composite Higgs\n  models from lattice gauge theory: We develop methods to calculate the electroweak gauge boson contribution to\nthe effective Higgs potential in the context of composite Higgs models, using\nlattice gauge theory. The calculation is analogous to that of the\nelectromagnetic mass splitting of the pion multiplet in QCD. We discuss\ntechnical details of carrying out this calculation, including modeling of the\nmomentum and fermion-mass dependence of the underlying current-current\ncorrelation function; direct integration of the correlation function over\nmomentum; and fits based on the minimal-hadron approximation. We show results\nof a numerical study using valence overlap fermions, carried out in an SU(4)\ngauge theory with two flavors of Dirac fermions in the two-index antisymmetric\nrepresentation."
    },
    {
        "anchor": "Quantum Simulation of Lattice QCD with Improved Hamiltonians: Quantum simulations of lattice gauge theories are anticipated to directly\nprobe the real time dynamics of QCD, but scale unfavorably with the required\ntruncation of the gauge fields. Improved Hamiltonians are derived to correct\nfor the effects of gauge field truncations on the SU(3) Kogut-Susskind\nHamiltonian. It is shown in $1+1D$ that this enables low chromo-electric field\ntruncations to quantitatively reproduce features of the untruncated theory over\na range of couplings and quark masses. In $3+1D$, an improved Hamiltonian is\nderived for lattice QCD with staggered massless fermions. It is shown in the\nstrong coupling limit that the spectrum qualitatively reproduces aspects of two\nflavor QCD and simulations of a small system are performed on IBM's {\\tt Perth}\nquantum processor.",
        "positive": "Polyakov Loops and Magnetic Screening from Monopoles in SU(2) Lattice\n  Gauge Theory: We present results from magnetic monopoles in $SU(2)$ lattice gauge theory at\nfinite temperature. The lattices are $16^{3}\\times N_{t}$, for\n$N_{t}=4,6,8,12$, at $\\beta=2.5115$. Quantities discussed are: the spacial\nstring tension, Polyakov loops, and the screening of timelike and spacelike\nmagnetic currents."
    },
    {
        "anchor": "Global Demons in Field Theory : Critical Slowing Down in the Xy Model: We investigate the use of global demons, a `canonical dynamics', as an\napproach to simulating lattice regularized field theories. This\ndeterministically chaotic dynamics is non-local and non-Hamiltonian, and\npreserves the canonical measure rather than $\\delta(H-E)$. We apply this\ninexact dynamics to the 2D XY model, comparing to various implementations of\nhybrid Monte Carlo, focusing on critical exponents and critical slowing down.\nIn addition, we discuss a scheme for making energy non-conserving dynamical\nalgorithms exact without the use of a Metropolis hit.",
        "positive": "Free energy for parameterized Polyakov loops in SU(2) and SU(3) lattice\n  gauge theory: We present a study of the free energy of parameterized Polyakov loops P in\nSU(2) and SU(3) lattice gauge theory as a function of the parameters that\ncharacterize P. We explore temperatures below and above the deconfinement\ntransition, and for our highest temperatures T > 5 T_c we compare the free\nenergy to perturbative results."
    },
    {
        "anchor": "Lattice Artefacts In The Non-Abelian Debye Screening Mass In One Loop\n  Order: We compute the electric screening mass in lattice QCD with Wilson fermions at\nfinite temperature and chemical potential to one-loop order, and show that\nlattice artefacts arising from a finite lattice spacing result in an\nenhancement of the screening mass as compared to the continuum. We discuss the\nmagnitude of this enhancement as a function of the temperature and chemical\npotential for lattices with different number of lattice sites in the temporal\ndirection that can be implemented in lattice simulations. Most of the\nenhancement is found to be due to the fermion loop contribution.",
        "positive": "Pion generalized parton distribution from lattice QCD: We present the first lattice calculation of the valence-quark generalized\nparton distribution (GPD) of the pion using the large-momentum effective theory\n(LaMET) approach. We focus on the zero-skewness limit, where the GPD has a\nprobability-density interpretation in the longitudinal Bjorken $x$ and the\ntransverse impact-parameter distributions. Our calculation is done using clover\nvalence fermions on an ensemble of gauge configurations with $2+1+1$ flavors\n(degenerate up/down, strange and charm) of highly improved staggered quarks\n(HISQ) with lattice spacing $a \\approx 0.12$ fm, box size $L \\approx 3$ fm and\npion mass $m_\\pi \\approx 310$ MeV. The parton distribution function and the\nform factor are reproduced as special limits of the GPD as expected. Due to the\nlarge errors, this exploratory study does not show a clear preference among\ndifferent model assumptions about the kinematic dependence of the GPD. To\ndiscriminate between these assumptions, future studies using higher-statistics\ndata will be crucial."
    },
    {
        "anchor": "Calorons, instantons and constituent monopoles in SU(3) lattice gauge\n  theory: We analyze the zero-modes of the Dirac operator in quenched SU(3) gauge\nconfigurations at non-zero temperature and compare periodic and anti-periodic\ntemporal boundary conditions for the fermions. It is demonstrated that for the\ndifferent boundary conditions often the modes are localized at different\nspace-time points and have different sizes. Our observations are consistent\nwith patterns expected for Kraan - van Baal solutions of the classical\nYang-Mills equations. These solutions consist of constituent monopoles and the\nzero-modes are localized on different constituents for different boundary\nconditions. Our findings indicate that the excitations of the QCD vacuum are\nmore structured than simple instanton-like lumps.",
        "positive": "Effective potential for SU(2) Polyakov loops and Wilson loop eigenvalues: We simulate SU(2) gauge theory at temperatures ranging from slightly below\n$T_c$ to roughly $2T_c$ for two different values of the gauge coupling. Using a\nhistogram method, we extract the effective potential for the Polyakov loop and\nfor the phases of the eigenvalues of the thermal Wilson loop, in both the\nfundamental and adjoint representations. We show that the classical potential\nof the fundamental loop can be parametrized within a simple model which\nincludes a Vandermonde potential and terms linear and quadratic in the Polyakov\nloop. We discuss how parametrizations for the other cases can be obtained from\nthis model."
    },
    {
        "anchor": "The spectral reconstruction of inclusive rates: A recently re-discovered variant of the Backus-Gilbert algorithm for spectral\nreconstruction enables the controlled determination of smeared spectral\ndensities from lattice field theory correlation functions. A particular\nadvantage of this approach is the \\emph{a priori} specification of the kernel\nwith which the underlying spectral density is smeared, allowing for variation\nof its peak position, smearing width, and functional form. If the unsmeared\nspectral density is sufficiently smooth in the neighborhood of a particular\nenergy, it can be obtained from an extrapolation to zero smearing-kernel width\nat fixed peak position. A natural application for this approach is scattering\nprocesses summed over all hadronic final states. As a proof-of-principle test,\nan inclusive rate is computed in the two-dimensional O(3) sigma model from a\ntwo-point correlation function of conserved currents. The results at finite and\nzero smearing radius are in good agreement with the known analytic form up to\nenergies at which 40-particle states contribute, and are sensitive to the\n4-particle contribution to the inclusive rate. The straight-forward adaptation\nto compute the $R$-ratio in lattice QCD from two-point functions of the\nelectromagnetic current is briefly discussed.",
        "positive": "An Accelerated Conjugate Gradient Algorithm to Compute Low-Lying\n  Eigenvalues --- a Study for the Dirac Operator in SU(2) Lattice QCD: The low-lying eigenvalues of a (sparse) hermitian matrix can be computed with\ncontrolled numerical errors by a conjugate gradient (CG) method. This CG\nalgorithm is accelerated by alternating it with exact diagonalisations in the\nsubspace spanned by the numerically computed eigenvectors. We study this\ncombined algorithm in case of the Dirac operator with (dynamical) Wilson\nfermions in four-dimensional $\\SUtwo$ gauge fields. The algorithm is\nnumerically very stable and can be parallelized in an efficient way. On\nlattices of sizes $4^4-16^4$ an acceleration of the pure CG method by a factor\nof~$4-8$ is found."
    },
    {
        "anchor": "Deflated GMRES with Multigrid for Lattice QCD: Lattice QCD solvers encounter critical slowing down for fine lattice spacings\nand small quark mass. Traditional matrix eigenvalue deflation is one approach\nto mitigating this problem. However, to improve scaling we study the effects of\ndeflating on the coarse grid in a hierarchy of three grids for adaptive\nmutigrid applications of the two dimensional Schwinger model. We compare\ndeflation at the fine and coarse levels with other non deflated methods. We\nfind the inclusion of a partial solve on the intermediate grid allows for a low\ntolerance deflated solve on the coarse grid. We find very good scaling in\nlattice size near critical mass when we deflate at the coarse level using the\nGMRES-DR and GMRES-Proj algorithms.",
        "positive": "Higher-order hadronic-vacuum-polarization contribution to the muon g-2\n  from lattice QCD: We introduce a new method for calculating the ${\\rm O}(\\alpha^3)$\nhadronic-vacuum-polarization contribution to the muon anomalous magnetic moment\nfrom ${ab-initio}$ lattice QCD. We first derive expressions suitable for\ncomputing the higher-order contributions either from the renormalized vacuum\npolarization function $\\hat\\Pi(q^2)$, or directly from the lattice\nvector-current correlator in Euclidean space. We then demonstrate the approach\nusing previously-published results for the Taylor coefficients of\n$\\hat\\Pi(q^2)$ that were obtained on four-flavor QCD gauge-field configurations\nwith physical light-quark masses. We obtain $10^{10} a_\\mu^{\\rm HVP,HO} =\n-9.3(1.3)$, in agreement with, but with a larger uncertainty than,\ndeterminations from $e^+e^- \\to {\\rm hadrons}$ data plus dispersion relations."
    },
    {
        "anchor": "Coulomb-gauge ghost and gluon propagators in SU(3) lattice Yang-Mills\n  theory: We study the momentum dependence of the ghost propagator and of the space and\ntime components of the gluon propagator at equal time in pure SU(3) lattice\nCoulomb gauge theory carrying out a joint analysis of data collected\nindependently at RCNP Osaka and Humboldt University Berlin. We focus on the\nscaling behavior of these propagators at beta=5.8,...,6.2 and apply a matching\ntechnique to relate the data for the different lattice cutoffs. Thereby,\nlattice artifacts are found to be rather strong for both instantaneous gluon\npropagators at large momentum. As a byproduct we obtain the respective lattice\nscale dependences a(beta) for the transversal gluon and the ghost propagator\nwhich indeed run faster with beta than two-loop running, but slightly slower\nthan what is known from the Necco-Sommer analysis of the heavy quark potential.\nThe abnormal a(beta) dependence as determined from the instantaneous time-time\ngluon propagator, D_{44}, remains a problem, though. The role of residual\ngauge-fixing influencing D_{44} is discussed.",
        "positive": "Beauty mesons in $N_f=2+1+1+1 $ lattice QCD with exact chiral symmetry: We present the first study of $N_f=2+1+1+1$ lattice QCD with domain-wall\nquarks. The $(b, c, s)$ quarks are physical, while the $(u, d)$ quarks are\nheavier than their physical masses, with the pion mass $ \\sim 700 $ MeV. The\ngauge ensemble is generated by hybrid Monte Carlo simulation with the Wilson\ngauge action for the gluons, and the optimal domain-wall fermion action for the\nquarks. Using point-to-point quark propagators, we measure the time-correlation\nfunctions of quark-antiquark meson interpolators with quark contents $\\bar b\nb$, $\\bar b c$, $\\bar b s$, and $ \\bar c c$, and obtain the masses of the\nlow-lying mesons. They are in good agreement with the experimental values, plus\nsome predictions which have not been observed in experiments. Moreover, we also\ndetermine the masses of $(b, c, s)$ quarks."
    },
    {
        "anchor": "Lattice QCD with 2+1 Flavors and Open Boundaries: First Results of the\n  Baryon Spectrum: Based on CLS simulations with 2+1 flavors and open boundaries we present\nfirst results of the baryon spectrum. We report on the status of our effort\nrelated to these simulations and the chiral extrapolation to the physical\npoint.",
        "positive": "A doubler-free lattice theory for QCD based on geometric fermions: We present doubler-free gauge-invariant lattice vector gauge action for some\nreal representations of Wilson gauge fields on an octet of fermions. It is\nbased on a geometric representation of the Dirac equation as an evolution\nequation on the three-dimensional exterior bundle /(R^3) for a single bispinor\nand of the bundle (/\\x/)(R^3) for an octet. We find doubler-free lattice Dirac\noperators for above bundles. A gauge-invariant connection with Wilson lattice\ngauge fields is possible for some real representations of the gauge group. The\nQCD action of SU(3) is of this type.\n  Application in lattice QCD seems useful: We don't have to waste time and\nmemory for doublers as well as for correction terms to suppress them."
    },
    {
        "anchor": "Spectrum of Mesons and Baryons with $b$ Quarks: We present highlights of the spectrum of mesons and baryons calculated using\nNRQCD for heavy quarks and tadpole improved clover action for the light quarks.",
        "positive": "High temperature critical O(N) field models by LCE series: The critical properties of renormalizable O(N) field models are determined by\nmeans of the high order ($\\geq 18$) behaviour of convergent linked cluster\nseries on finite temperature lattices. It is shown that those models become\nweakly coupled at the phase transition. The critical exponents agree to those\nof the corresponding superrenormalizable 3-dimensional models. Concerning\ncritical amplitudes and subcritical behaviour, corrections induced by\nrenormalizable couplings are measurable."
    },
    {
        "anchor": "Abelian and Nonabelian Lattice Chiral Gauge Theories through Gauge\n  Fixing: After an introduction in which we review the fundamental difficulty in\nconstructing lattice chiral gauge theories, we summarize the analytic and\nnumerical evidence that abelian lattice chiral gauge theories can be\nnonperturbatively constructed through the gauge-fixing approach. In addition,\nwe indicate how we believe that the method may be extended to nonabelian chiral\ngauge theories.",
        "positive": "Bound states of multi-nucleon channels in N_f=2+1 lattice QCD: We calculate the energies for multi-nucleon ground states with the nuclear\nmass number less than or equal to 4 in 2+1 flavor QCD at the lattice spacing of\na = 0.09 fm employing a relatively heavy quark mass corresponding to m_pi =\n0.51 GeV. We investigate the volume dependence of the energy shift of the\nground state and the state of free nucleons to distinguish a bound state from\nattractive scattering states. From the investigation we conclude that ^4He,\n^3He, deuteron and dineutron are bound at m_pi = 0.51 GeV. We compare their\nbinding energies with those in our quenched studies and also with some recent\ninvestigations."
    },
    {
        "anchor": "Instanton-like Contributions to the Dynamics of Yang-Mills Fields on the\n  Twisted Torus: We study $SU(2)$ lattice gauge theory in small volumes and with twist\n$\\vec{m}=(1,1,1)$. We investigate the presence of the periodic instantons of\n$Q=\\frac{1}{2}$ and determine their free energy and their contribution to the\nsplitting of energy flux sectors \\mbox{$E(\\vec{e}=(1,1,1))-E(\\vec{e}=(0,0,0))\n$.}",
        "positive": "High-temperature expansions through order 24 for the two-dimensional\n  classical XY model on the square lattice: The high-temperature expansion of the spin-spin correlation function of the\ntwo-dimensional classical XY (planar rotator) model on the square lattice is\nextended by three terms, from order 21 through order 24, and analyzed to\nimprove the estimates of the critical parameters."
    },
    {
        "anchor": "Finite volume effects for the pion mass at two loops: We evaluate the pion mass in finite volume to two loops within Chiral\nPerturbation Theory. The results are compared with a recently proposed\nextension of the asymptotic formula of Luscher. We find that contributions,\nwhich were neglected in the latter, are numerically very small at the two-loop\nlevel and conclude that for Mpi*L>2, L>2fm the finite volume effects in the\nmeson sector are analytically well under control.",
        "positive": "Monopole-like Quantum Excitations in the Non-abelian Vacuum: It is offered to consider monopoles in Abelian Projection as quantum\nexcitations which are solutions of the quantized Yang-Mills equations.\nAccording to the Heisenberg quantization method these equations are equivalent\nan infinite set of equations for Green's functions. A procedure for cutting off\nthese infinite series of differential equations after some assumptions is\noffered. The received equations are identical to equations describing a dyon."
    },
    {
        "anchor": "Strategies for quantum-optimized construction of interpolating operators\n  in classical simulations of lattice quantum field theories: It has recently been argued that noisy intermediate-scale quantum computers\nmay be used to optimize interpolating operator constructions for lattice\nquantum field theory (LQFT) calculations on classical computers. Here, two\nconcrete realizations of the method are developed and implemented. The first\napproach is to maximize the overlap, or fidelity, of the state created by an\ninterpolating operator acting on the vacuum state to the target eigenstate. The\nsecond is to instead minimize the energy expectation value of the interpolated\nstate. These approaches are implemented in a proof-of-concept calculation in\n(1+1)-dimensions for a single-flavor massive Schwinger model to obtain\nquantum-optimized interpolating operator constructions for a vector meson state\nin the theory. Although fidelity maximization is preferable in the absence of\nnoise due to quantum gate errors, it is found that energy minimization is more\nrobust to these effects in the proof-of-concept calculation. This work serves\nas a concrete demonstration of how quantum computers in the intermediate term\nmight be used to accelerate classical LQFT calculations.",
        "positive": "Improving flavor symmetry in the Kogut-Susskind hadron spectrum: We study the effect of modifying the coupling of Kogut-Susskind quarks to the\ngauge field by replacing the link matrix in the quark action by a \"fat link\",\nor sum of link plus three-link paths. Flavor symmetry breaking, determined by\nthe mass difference between the Goldstone and non-Goldstone local pions, is\nreduced by approximately a factor of two by this modification."
    },
    {
        "anchor": "Gluon Dynamics, Center Symmetry and the deconfinement phase transition\n  in SU(3) pure Yang-Mills theory: The correlations between the modulus of the Polyakov loop, its phase $\\theta$\nand the Landau gauge gluon propagator at finite temperature are investigated in\nconnection with the center symmetry for pure Yang-Mills SU(3) theory. In the\ndeconfined phase, where the center symmetry is spontaneously broken, the phase\nof the Polyakov loop per configuration is close to $\\theta = 0$, $\\pm \\, 2 \\pi\n/3$. We find that the gluon propagator form factors associated with $\\theta\n\\approx 0$ differs quantitatively and qualitatively from those associated to\n$\\theta \\approx \\pm \\, 2 \\pi /3$. This difference between the form factors is a\nproperty of the deconfined phase and a sign of the spontaneous breaking of the\ncenter symmetry. Furthermore, given that this difference vanishes in the\nconfined phase, it can be used as an order parameter associated to the\ndeconfinement transition. For simulations near the critical temperature $T_c$,\nthe difference between the propagators associated to $\\theta \\approx 0$ and\n$\\theta \\approx \\pm \\, 2 \\pi /3$ allows to classify the configurations as\nbelonging to the confined or deconfined phase. This establishes a selection\nprocedure which has a measurable impact in the gluon form factors. Our results\nalso show that the absence of the selection procedure can be erroneously taken\nas lattice artifacts.",
        "positive": "Finite size effect on vector meson and baryon sectors in 2+1 flavor QCD\n  at the physical point: We investigate the finite size effect on the vector meson and the baryon\nsectors using a subset of the \"PACS10\" configurations which are generated,\nkeeping the space-time volumes over (10 fm$)^4$ in 2+1 flavor QCD at the\nphysical point. Comparing the results on (5.5 fm$)^4$ and (10.9 fm$)^4$\nlattices the ground states of octet baryons , which are stable on the lattice,\nshow no finite size effect within less than 0.5% level of statistical errors.\nFor those of vector mesons, which are unstable on the lattice, we observe that\nthe effective masses are well below the experimental resonance levels both on\n(5.5 fm$)^4$ and (10.9 fm$)^4$ lattices. For the decuplet baryon sector we have\nfound that the time dependence of the effective mass looks quite similar to\nthat for the vector meson sector including the $\\Omega$ baryon channel. We\ndiscuss its origin due to a possible mixing with the nearby multihadron states.\nSince the $\\Xi$ baryon mass can be determined with the smallest ambiguity among\nthe vector meson and the baryon masses, we use it together with the pion and\nkaon masses as the physical inputs to determine the physical point."
    },
    {
        "anchor": "Divergences in the quark number susceptibility : The origin and a cure: Quark number susceptibility on the lattice, obtained by merely adding a $\\mu\nN$ term with $\\mu$ as the chemical potential and $N$ as the conserved quark\nnumber, has a quadratic divergence in the cut-off $a$. We show that such a\ndivergence already exist for free fermions with a cut-off regulator. While one\ncan eliminate it in the free lattice theory by suitably modifying the action,\nas is popularly done, it can simply be subtracted off as well. Computations of\nhigher order susceptibilities, needed for estimating the location of the QCD\ncritical point, then need a lot fewer number of quark propagators at any order.\nWe show that this method of divergence removal works in the interacting theory.",
        "positive": "One-loop renormalization of fermionic currents with the overlap-Dirac\n  operator: We compute the one-loop lattice renormalization of the two-quark operators\n$\\bar{\\psi} \\Gamma \\psi$, where $\\Gamma$ denotes the generic Dirac matrix, for\nthe lattice formulation of QCD using the overlap-Dirac operator.\n  We also study the renormalization of quark bilinears which are more extended\nand have better chiral properties.\n  Finally, we present improved estimates of these renormalization constants,\ncoming from cactus resummation and from mean field perturbation theory."
    },
    {
        "anchor": "Density, short-range order and the quark-gluon plasma: We study the thermal part of the energy density spatial correlator in the\nquark-gluon plasma. We describe its qualitative form at high temperatures. We\nthen calculate it out to distances approx. 1.5/T in SU(3) gauge theory lattice\nsimulations for the range of temperatures 0.9<= T/T_c<= 2.2. The\nvacuum-subtracted correlator exhibits non-monotonic behavior, and is almost\nconformal by 2T_c. Its broad maximum at r approx. 0.6/T suggests a dense medium\nwith only weak short-range order, similar to a non-relativistic fluid near the\nliquid-gas phase transition, where eta/s is minimal.",
        "positive": "Resolving the scales of the Yang-Mills theory by means of an extra\n  dimension: The Yang-Mills theory is part of the Standard Model of particle physics. The\nlack of the mathematical understanding of the theory stands out in theoretical\nphysics. In order to address this problem we observe that a recently proposed\ngeneral model beyond the Standard Model resolves the energy scales of a lattice\nregularized Yang-Mills theory by means of an extra dimension. The extra\ndimension ensures that all intermediate length scales of the physical system\nare available by definition. In this paper we study the role of the extra\ndimension also in the case of the free boson field. We find that if the extra\ndimension size is large, the model describes the classical motion of the\nsystem. In the opposite limit we recover its standard quantum mechanical motion\nwithout loss of information. Therefore, the Hilbert space of states in the\npresence of the extra dimension describes physical phenomena at all energy\nscales. This observation allows us to raise the description of length scales by\nan extra dimension at the level of a principle for the theories beyond the\nStandard Model, the only modeling constraint being the correspondence\nprinciple. As it was shown recently, the fermion ground state energy of a gauge\ninvariant Hamilton operator of Dirac fermions gives a particular lattice\nregularization of the Yang-Mills theory. Integration of gauge fields gives a\npure fermion theory of color singlet fermion-antifermion pairs at each lattice\nsite evolving along the extra dimension. Color confinement follows directly\nfrom this property. It allows for a saddle point solution in the limit of a\nlarge number of colors. In this paper we find that the glueball spectrum of the\nYang-Mills regularized theory is of the Hagedron type and bounded below by a\npositive value. We show also that the color charge is screened and the\nquark-antiquark potential is constant."
    },
    {
        "anchor": "Dense $\\textrm{QCD}_2$ with matrix product states: We study one-flavor $\\mathrm{SU}(2)$ and $\\mathrm{SU}(3)$ lattice QCD in\n($1+1$) dimensions at zero temperature and finite density using matrix product\nstates and the density matrix renormalization group. We compute physical\nobservables such as the equation of state, chiral condensate, and quark\ndistribution function as functions of the baryon number density. As a physical\nimplication, we discuss the inhomogeneous phase at nonzero baryon density,\nwhere the chiral condensate is inhomogeneous, and baryons form a crystal. We\nalso discuss how the dynamical degrees of freedom change from hadrons to quarks\nthrough the formation of quark Fermi seas.",
        "positive": "Structure and properties of the vacuum of the Twisted Eguchi-Kawai model: We investigate numerically the phase structure of the Twisted Eguchi-Kawai\n(TEK) model in four dimensions. In the numerical simulations of the zero\ntemperature TEK model (using a symmetric twist) we observe the existence of new\nphases that break its centre symmetry at intermediate lattice couplings and for\nlarge SU(N) gauge groups. This effect can be explained by the contribution of\ndiagonal configurations with collapsed eigenvalues, which are particular cases\nof ``generalised fluxons''. We also investigate finite temperature versions of\nthe TEK model using anisotropic lattice couplings, where in particular we find\nvan Baal fluxons contributing at large anisotropies."
    },
    {
        "anchor": "Four quark operators for kaon bag parameter with gradient flow: To study the CP-violation using the $K_0-\\bar{K}_0$ oscillation, we need the\nkaon bag parameter which represents QCD corrections in the leading Feynman\ndiagrams. The lattice QCD provides us with the only way to evaluate the kaon\nbag parameter directly from the first principles of QCD. However, a calculation\nof relevant four quark operators with theoretically sound Wilson-type lattice\nquarks had to carry a numerically big burden of extra renormalizations and\nresolution of extra mixings due to the explicit chiral violation. Recently, the\nSmall Flow-time eXpansion (SFtX) method was proposed as a general method based\non the gradient flow to correctly calculate any renormalized observables on the\nlattice, irrespective of the explicit violations of related symmetries on the\nlattice. To apply the SFtX method, we need matching coefficients, which relate\nfinite operators at small flow-times in the gradient flow scheme to\nrenormalized observables in conventional renormalization schemes. In this\npaper, we calculate the matching coefficients for four quark operators and\nquark bi-linear operators, relevant to the kaon bag parameter.",
        "positive": "The end point of the first-order phase transition of the SU(2)\n  gauge-Higgs model on a four-dimensional isotropic lattice: We report results of a study of the end point of the electroweak phase\ntransition of the SU(2) gauge-Higgs model defined on a four-dimensional\nisotropic lattice with N_t=2. Finite-size scaling study of Lee-Yang zeros\nyields lambda_c=0.00116(16) for the end point. Combined with a zero-temperature\nmeasurement of Higgs and W boson masses, this leads to M_{H,c}=68.2+-6.6 GeV\nfor the critical Higgs boson mass. An independent analysis of Binder cumulant\ngives a consistent value lambda_c=0.00102(3) for the end point."
    },
    {
        "anchor": "Vector and scalar form factors for K- and D-meson semileptonic decays\n  from twisted mass fermions with Nf = 2: We present lattice results for the form factors relevant in the K -> pion and\nD -> pion semileptonic decays, obtained from simulations with two flavors of\ndynamical twisted-mass fermions and pion masses as light as 260 MeV. For K ->\npion decays we discuss the estimates of the main sources of systematic\nuncertainties, including the quenching of the strange quark, leading to our\nfinal result f+(0) = 0.9560 (57) (62). Combined with the latest experimental\ndata, our value of f+(0) implies for the CKM matrix element |Vus| the value\n0.2267 (5) (20) consistent with the first-row CKM unitarity. For D -> pion\ndecays the application of Heavy Meson Chiral Perturbation Theory allows to\nextrapolate our results for both the scalar and the vector form factors at the\nphysical point with quite good accuracy, obtaining a nice agreement with the\nexperimental data. In particular at zero-momentum transfer we obtain f+(0) =\n0.64 (5).",
        "positive": "The dimer partition function: We apply the Ginzburg criterion to the dimer problem and we solve the\napparent contradiction of a system with mean field $\\alpha={1\\over2}$, the\ntypical value of tricritical systems, and upper critical dimension $D_{cr}=6$.\nWe find that the system has upper critical dimension $D_{cr}=6$ , while for\n$D\\le4$ it should undergo a first order phase transition. We comment on the\nlatter wrong result examining the approximation we used."
    },
    {
        "anchor": "$K -> \u03c0\u03c0$ and $\u03b5^\\prime/\u03b5$ using domain wall fermions: This paper has been withdrawn.",
        "positive": "Mass splittings in a linear sigma model for multiflavor gauge theories: We calculate the tree-level mass spectrum for a linear sigma model describing\nthe scalar and pseudoscalar mesons of a $SU(3)$ local gauge theory with Dirac\nfermions in the fundamental representation. $N_1$ fermions have a mass $m_1$\nand $N_2$ a mass $m_2$. Using recent lattice data with $m_1=m_2$ and $N_1+N_2$=\n8 or 12, we predict the mass splittings for $m_2=m_1+\\delta m$. At first order\nin $\\delta m$, an interesting inverted pattern appears in the $0^{++}$ sector,\nwhere mesons with lighter fermions are heavier. This feature could be tested in\nongoing calculations provided that $m_1$ and $\\delta m$ are sufficiently small.\nWe discuss possible improvements of the approach."
    },
    {
        "anchor": "Energies and radial distributions of B_s mesons - the effect of\n  hypercubic blocking: This is a follow-up to our earlier work for the energies and the charge\n(vector) and matter (scalar) distributions for S-wave states in a heavy-light\nmeson, where the heavy quark is static and the light quark has a mass about\nthat of the strange quark. We study the radial distributions of higher angular\nmomentum states, namely P- and D-wave states, using a \"fuzzy\" static quark. A\nnew improvement is the use of hypercubic blocking in the time direction, which\neffectively constrains the heavy quark to move within a 2a hypercube (a is the\nlattice spacing).\n  The calculation is carried out with dynamical fermions on a 16^3 times 32\nlattice with a lattice spacing approximately 0.10 fm generated using the\nnon-perturbatively improved clover action. The configurations were generated by\nthe UKQCD Collaboration using lattice action parameters beta = 5.2, c_SW =\n2.0171 and kappa = 0.1350.\n  In nature the closest equivalent of this heavy-light system is the B_s meson.\nAttempts are now being made to understand these results in terms of the Dirac\nequation.",
        "positive": "Rare B decays with moving NRQCD and improved staggered quarks: We calculate form factors relevant for rare B decays using moving-NRQCD for\nthe b quark and the AsqTad action for the light quarks. Moving NRQCD allows us\nto work directly with the physical b quark mass and go to higher recoil\nmomentum compared to standard NRQCD. Here, we show first results for the matrix\nelements and the operator matching coefficients. Some difficulties and possible\nways of improvement are discussed."
    },
    {
        "anchor": "Casimir Scaling of domain wall tensions in the deconfined phase of D=3+1\n  SU(N) gauge theories: We perform lattice calculations of the spatial 't Hooft k-string tensions in\nthe deconfined phase of SU(N) gauge theories for N=2,3,4,6. These equal (up to\na factor of T) the surface tensions of the domain walls between the\ncorresponding (Euclidean) deconfined phases. For T much larger than T_c our\nresults match on to the known perturbative result, which exhibits Casimir\nScaling, being proportional to k(N-k). At lower T the coupling becomes stronger\nand, not surprisingly, our calculations show large deviations from the\nperturbative T-dependence. Despite this we find that the behaviour proportional\nto k(N-k) persists very accurately down to temperatures very close to T_c. Thus\nthe Casimir Scaling of the 't Hooft tension appears to be a `universal' feature\nthat is more general than its origin in the low order high-T perturbative\ncalculation. We observe the `wetting' of these k-walls at T around T_c and the\n(almost inevitable) `perfect wetting' of the k=N/2 domain wall. Our\ncalculations show that as T tends to T_c the magnitude of the spatial `t Hooft\nstring tension decreases rapidly.",
        "positive": "Hadronic light-by-light contribution to $(g-2)_\u03bc$ from lattice QCD: a\n  complete calculation: We compute the hadronic light-by-light scattering contribution to the muon\n$g-2$ from the up, down, and strange-quark sector directly using lattice QCD.\nOur calculation features evaluations of all possible Wick-contractions of the\nrelevant hadronic four-point function and incorporates several different pion\nmasses, volumes, and lattice-spacings. We obtain a value of\n$a_\\mu^{\\text{Hlbl}} = 106.8(14.7) \\times 10^{-11}$ (adding statistical and\nsystematic errors in quadrature), which is consistent with current\nphenomenological estimates and a previous lattice determination. It now appears\nconclusive that the hadronic light-by-light contribution cannot explain the\ncurrent tension between theory and experiment for the muon $g-2$."
    },
    {
        "anchor": "Triply charmed baryons mass decomposition from lattice QCD: We present the first lattice QCD calculation about the mass decomposition of\ntriply charmed baryons with $J^{P}$ as $\\frac{3}{2}^{+}$ and $\\frac{3}{2}^{-}$.\nThe quark mass term $\\langle H_{M} \\rangle$ contributes about 66\\% to the mass\nof $\\frac{3}{2}^+$ state, which is slightly lower than that of the meson system\nwith the same valence charm quark. Furthermore, based on our results, the total\ncontribution of sea quarks, the gluons and the QCD anomaly accounts for about a\nquarter of the mass of these two triply charmed baryons. The mass difference of\n$\\frac{3}{2}^+$ and $\\frac{3}{2}^-$ states is mainly from the quark energy\n$\\langle H_{E} \\rangle$ of the QCD energy-momentum tensor. For comparison, the\nmass splitting is also calculated under the framework of the constituent quark\nmodel.",
        "positive": "The Stochastic Feynman-Hellmann Method: The Feynman-Hellmann method, as implemented by Bouchard et al. [1612.06963],\nwas recently employed successfully to determine the nucleon axial charge. A\nlimitation of the method was the restriction to a single operator and a single\nmomentum during the computation of each \"Feynman- Hellmann\" propagator. By\nusing stochastic techniques to estimate the all-to-all propagator, we relax\nthis constraint and demonstrate the successful implementation of this new\nmethod. We show reproduction of the axial charge on a test ensemble and\nnon-zero momentum transfer points of the axial and vector form factors."
    },
    {
        "anchor": "The Poincare Group of Discrete Minkowskian Space-Time: The lattice of integral points of 4-dimensional Minkowski space, together\nwith the inherited indefinite distance function, is considered as a model for\ndiscrete space-time. The Lorentz and Poincare groups of this discrete\nspace-time are identified as subgroups of the corresponding Lie groups. The\nlattice Lorentz group has irreducible projective (including linear)\nrepresentations which are restrictions of (all) finite-dimensional irreducible\nprojective representations of the Lorentz Lie group and hence can be used to\ndescribe all integral and half-odd-integral helicity. The (4-torus) momentum\nspace has a well-defined ``light cone'' of null points and there are orbits of\nthe lattice Lorentz group lying entirely in the torus light cone and having the\nlattice euclidean group of the plane as little group. Wigner's method for the\nPoincare Lie group can then be adapted to show, in the first instance, that the\nlattice Poincare group has unitary representations describing lattice free\nfields of zero mass and an arbitrary Lorentz helicity, in particular chiral\nfermions. There are no representations with a nonzero invariant mass.",
        "positive": "Implementation of the Neuberger-Dirac operator on GPUs: Recent developments have shown that a lot can be gained for QCD simulations\nfrom GPU hardware. This can be exploited especially in the case of\nGinsparg-Wilson fermions when the com putational costs are particularly high.\nIn this work, we use the Neuberger-Dirac operator as our realisation of\nGinsparg-Wilson fermions, which greatly facilitate lattice investigations of\ndecays like $K \\to \\pi\\pi$. We report on the ongoing study of our GPU\nimplementation of the Neuberger-Dirac operator including the exact treatment of\nthe low lying eigenmodes of the Wilson-Dirac operator. Our benchmarks show that\nwe achieve speed-up factors of around 23 and 16 in single and double precision,\nrespectively."
    },
    {
        "anchor": "Detection of Center Vortices in the Lattice Yang-Mills Vacuum: We discuss the implementation of the ``direct'' maximal center gauge (a gauge\nwhich maximizes the lattice average of the squared-modulus of the trace of link\nvariables), and its use in identifying Z(2) center vortices in Yang-Mills\nvacuum configurations generated by lattice Monte Carlo. We find that center\nvortices identified in the vacuum state account for the full asymptotic string\ntension. Scaling of vortex densities with lattice coupling, change in vortex\nsize with cooling, and sensitivity to Gribov copies is discussed. Preliminary\nevidence is presented, on small lattices, for center dominance in SU(3) lattice\ngauge theory.",
        "positive": "Structure of the QCD Vacuum As Seen By Lattice Simulations: This talk is a review of our studies of instantons and their properties as\nseen in our lattice simulations of SU(2) gauge theory. We have measured the\ntopological susceptibility and the size distribution of instantons in the QCD\nvacuum.\n  We have also investigated the properties of quarks moving in instanton\nbackground field configurations, where the sizes and locations of the\ninstantons are taken from simulations of the full gauge theory. By themselves,\nthese multi-instanton configurations do not confine quarks, but they induce\nchiral symmetry breaking."
    },
    {
        "anchor": "Baryon correlators containing different diquarks from lattice\n  simulations: Point to point vacuum correlators containing diquarks in the color\nanti-triplet representation are computed both in the quenched approximation and\ndynamical overlap simulations with two flavors. The scalar, pseudoscalar and\naxial vector diquarks are combined with light quarks to form color singlets.\nThe scalar (\"good\") diquark channel shows a stronger attraction than the axial\nvector (\"bad\") channel in the quenched data set. The pseudoscalar diquark\nchannel shows a finite volume zero mode artifact: the correlator becomes\nnegative at large distance when the quark mass is small. By separating\nconfigurations without zero modes from those with zero modes, we found that the\nzero modes have an important contribution in both the attraction in the scalar\nchannel and the repulsion in the pseudoscalar channel. In the axial vector\ndiquark channel, we did not find apparent zero mode effects.",
        "positive": "String breaking: We numerically investigate the transition of the static quark-antiquark\nstring into a static-light meson-antimeson system. Improving noise reduction\ntechniques, we are able to resolve the signature of string breaking dynamics\nfor Nf=2 lattice QCD at zero temperature. We discuss the lattice techniques\nused and present results on energy levels and mixing angle of the static\ntwo-state system. We visualize the action density distribution in the region of\nstring breaking as a function of the static colour source-antisource\nseparation. The results can be related to properties of quarkonium systems."
    },
    {
        "anchor": "Taylor expansions and Pad\u00e9 approximants for cumulants of conserved\n  charge fluctuations at non-vanishing chemical potentials: Using high statistics datasets generated in (2+1)-flavor QCD calculations at\nfinite temperature we present results for low order cumulants of net\nbaryon-number fluctuations at non-zero values of the baryon chemical potential.\nWe calculate Taylor expansions for the pressure (zeroth order cumulant), net\nbaryon-number density (first order cumulant) and the variance of the\ndistribution on net-baryon number fluctuations (second order cumulant). We\nobtain series expansions from an eighth order expansion of the pressure and\ncompare these to diagonal Pad\\'e approximants. This allows us to estimate the\nrange of values for the baryon chemical potential in which these expansions are\nreliable. We find $\\mu_B/T\\le 2.5$, $2.0$ and $1.5$ for the zeroth, first and\nsecond order cumulants, respectively. We furthermore, construct estimators for\nthe radius of convergence of the Taylor series of the pressure. In the vicinity\nof the pseudo-critical temperature, $T_{pc}\\simeq 156.5$ MeV, we find $\\mu_B/T\n\\gtrsim\\ 2.9$ at vanishing strangeness chemical potential and somewhat larger\nvalues for strangeness neutral matter. These estimates are temperature\ndependent and range from $\\mu_B/T \\gtrsim\\ 2.2$ at $T=135$ MeV to $\\mu_B/T\\\n\\gtrsim\\ 3.2$ at $T=165$ MeV. The estimated radius of convergences is the same\nfor any higher order cumulant.",
        "positive": "A physicist-friendly reformulation of the Atiyah-Patodi-Singer index (on\n  a lattice): The Atiyah-Singer index theorem on a closed manifold is well understood and\nappreciated in physics. On the other hand, the Atiyah-Patodi-Singer index,\nwhich is an extension to a manifold with boundary, is physicist-unfriendly, in\nthat it is formulated with a nonlocal boundary condition. Recently we proved\nthat the same index as APS is obtained from the domain-wall fermion Dirac\noperator. Our theorem indicates that the index can be expressed without any\nnonlocal conditions, in such a physicist-friendly way that application to the\nlattice gauge theory is straightforward. The domain-wall fermion provides a\nnatural mathematical foundation for understanding the bulk-edge correspondence\nof the anomaly inflow."
    },
    {
        "anchor": "QCD Thermodynamics and Neutral Pion in a Uniform Magnetic Field: Finite\n  Volume Effects: We address finite volume effects of lattice QCD calculations in background\nmagnetic fields. Using chiral perturbation theory at next-to-leading order,\nvolume effects are calculated for thermodynamic quantities: the chiral\ncondensate, pressure anisotropy, and magnetization. The neutral pion effective\naction in a finite volume is additionally derived. For these charge neutral\nobservables, volume and source averaging are shown to capitalize on magnetic\nperiodicity, which is the remnant translational invariance of the finite-volume\ntheory. For a fixed magnetic field strength, certain volume and source averaged\nquantities are independent of the size of the lattice transverse to the\nmagnetic field. Despite this simplifying feature, finite volume corrections to\nthe magnetic field dependence of the chiral condensate and neutral pion\nmagnetic polarizability can be non-negligible. The pressure anisotropy at fixed\nmagnetic flux, moreover, appears acutely sensitive to the lattice volume.",
        "positive": "Gluon excitations of the static-quark potential: The spectrum of gluon excitations in the presence of a static quark-antiquark\npair is presented. Our results are obtained from computer simulations of gluons\non anisotropic space-time lattices using an improved gauge-field action.\nMeasurements for quark-antiquark separations r ranging from 0.1 fm to 4 fm and\nfor various orientations on the lattice are made. Discretization errors and\nfinite volume effects are taken into account. Surprisingly, the spectrum does\nnot exhibit the expected onset of the universal pi/r Goldstone excitations of\nthe effective QCD string, even for r as large as 4 fm."
    },
    {
        "anchor": "Simulating thimble regularization of lattice quantum field theories: Monte Carlo simulations of lattice quantum field theories on Lefschetz\nthimbles are non trivial. We discuss a new Monte Carlo algorithm based on the\nidea of computing contributions to the functional integral which come from\ncomplete flow lines. The latter are the steepest ascent paths attached to\ncritical points, i.e. the basic building blocks of thimbles. The measure to\nsample is thus dictated by the contribution of complete flow lines to the\npartition function. The algorithm is based on a heat bath sampling of the\ngaussian approximation of the thimble: this defines the proposals for a\nMetropolis-like accept/reject step. The effectiveness of the algorithm has been\ntested on a few models, e.g. the chiral random matrix model. We also discuss\nthimble regularization of gauge theories, and in particular the successfull\napplication to 0+1 dimensional QCD and the status and prospects for Yang-Mills\ntheories.",
        "positive": "Comparison of Improved and Unimproved Quenched Hadron Spectroscopy: We make a comparison between our quenched-hadron-spectroscopy results for the\nnon-perturbatively-improved Wilson action and the corresponding unimproved\ncase, at beta=6.2 on the same set of gauge configurations. Within our\nstatistics, we find a sizeable improvement for the baryon spectrum and for the\ndetermination of the strange-quark mass."
    },
    {
        "anchor": "Generalisations of the Ginsparg-Wilson relation and a remnant of\n  supersymmetry on the lattice: We introduce a lattice symmetry relation for field theories with general\nlinear symmetries. For chiral symmetry the well-known Ginsparg-Wilson relation\nis reproduced. The new relation encodes the remnant of the original symmetry on\nthe lattice and guides the construction of invariant lattice actions. We apply\nthis approach to lattice supersymmetry. There, an additional constraint has to\nbe satisfied which originates in the derivative operator in the symmetry\ntransformations. As a consequence the non-local SLAC derivative operator\nappears in the lattice transformation. Despite this non-local form we show how\nlocal solutions for quadratic actions can be found. For interacting theories\nthe relation in general leads to a non-polynomial action that can be reduced to\na finite polynomial order only under certain conditions.",
        "positive": "Charmonium-nucleon interaction from lattice QCD with a relativistic\n  heavy quark action: Detailed information of the low-energy interaction between the charmonia\n({\\eta}c and J/{\\psi}) and the nucleon is indispensable for exploring the\nformation of charmonium bound to nuclei. In order to investigate the\ncharmonium-nucleon interactions at low energies, we adopt two essentially\ndifferent approaches in lattice QCD simulations. The charmonium-nucleon\npotential can be calculated from the equal-time Bethe-Salpeter amplitude\nthrough the effective Schr\\\"odinger equation. This novel method is based on the\nsame idea originally applied for the nucleon force by Aoki- Hatsuda-Ishii.\nAnother approach is to utilize extended L\\\"uscher's formula with partially\ntwisted boundary conditions, which allows us to calculate the s-wave phase\nshift at any small value of the relative momentum even in a finite box. We then\nextract model independent information of the scattering length and the\neffective range from the phase shift through the effective-range expansion. Our\nsimulations are carried out at a lattice cutoff of $1/a \\approx$ 2 GeV in a\nspatial volume of (3 fm)^3 with the non-perturbatively O(a)-improved Wilson\nfermions for the light quarks and a relativistic heavy quark action for the\ncharm quark. Although our main results are calculated in quenched lattice\ncalculations, we also present a preliminary full QCD result by using the 2+1\nflavor gauge configurations generated by PACS-CS Collaboration. We have found\nthat the charmonium-nucleon potential is weakly attractive at short distances\nand exponentially screened at large distances. We have also successfully\nevaluated both the scattering length and effective range from the\ncharmonium-nucleon scattering phase shift."
    },
    {
        "anchor": "Two-dimensional Gross-Neveu Model with Wilson Fermion Action at Finite\n  Temperature and Density: We analytically investigate the 2-dimensional Gross-Neveu model at finite\ntemperature and density using Wilson fermion action. The relation between the\nphase structure on the lattice and that in the continuum is clarified.",
        "positive": "A New Exact Method for Dynamical Fermion Computations with Non-Local\n  Actions: We introduce a new algorithm which we call the {Rational Hybrid Monte Carlo}\nAlgorithm (RHMC). This method uses a rational approximation to the fermionic\nkernel together with a noisy Kennedy-Kuti acceptance step to give an efficient\nalgorithm with no molecular dynamics integration step-size errors."
    },
    {
        "anchor": "Lattice NRQCD study of in-medium bottomonium states using $N_f = 2+1,\n  48^3 \\times 12$ HotQCD configurations: The behavior of bottomonium state correlators at non-zero temperature, $140.4\n(\\beta = 6.664) \\le T \\le 221 (\\beta = 7.280)$ (MeV), where the transition\ntemperature is $154(9)$ (MeV), is studied, using lattice NRQCD on $48^3 \\times\n12$ HotQCD HiSQ action configurations with light dynamical $N_f = 2 + 1$\n($m_{u,s}/m_s = 0.05$) staggered quarks. In order to understand finite\ntemperature effects on quarkonium states, zero temperature behavior of\nbottomonium correlators is compared based on $32^4$ ($\\beta = 6.664, 6.800$ and\n$6.950$) and $48^3 \\times 64$ ($\\beta = 7.280)$ lattices. We find that\ntemperature effects on S-wave bottomonium states are small but P-wave\nbottomonium states show a noticeable temperature dependence above the\ntransition temperature.",
        "positive": "Lattice calculations on the spectrum of Dirac and Dirac-K\u00e4hler\n  operators: We present a matrix technique to obtain the spectrum and the analytical index\nof some elliptic operators defined on compact Riemannian manifolds. The method\nuses matrix representations of the derivative which yield exact values for the\nderivative of a trigonometric polynomial. These matrices can be used to find\nthe exact spectrum of an elliptic operator in particular cases and in general,\nto give insight into the properties of the solution of the spectral problem. As\nexamples, the analytical index and the eigenvalues of the Dirac operator on the\ntorus and on the sphere are obtained and as an application of this technique,\nthe spectrum of the Dirac-Kahler operator on the sphere is explored."
    },
    {
        "anchor": "Supersymmetric Yang-Mills Theories from Domain Wall Fermions: We present work in progress on employing domain wall fermions to simulate N=1\nsupersymmetric Yang-Mills theories on the lattice in d=4 and d=3 dimensions.\nThe geometrical nature of domain wall fermions gives simple insights into how\nto construct these theories. We also discuss the obstacles associated with\nsimulating the N=2 theory in d=4.",
        "positive": "Four-quark systems: In order to understand the binding of four static quarks, flux distributions\ncorresponding to these binding energies are studied in quenched SU(2) and also\nrelated to a model for the energies. The potential relevant to string breaking\nbetween two heavy-light mesons is measured in quenched SU(3) using stochastic\nestimates of light quark propagators with the Sheikholeslami-Wohlert action."
    },
    {
        "anchor": "Light quark vacuum polarization at the physical point and contribution\n  to the muon $g-2$: We report on the computation of the connected light quark vacuum polarization\nwith 2+1+1 flavors of HISQ fermions at the physical point and its contribution\nto the muon anomalous magnetic moment. Three ensembles, generated by the MILC\ncollaboration, are used to take the continuum limit. The finite volume\ncorrection to this result is computed in the (Euclidean) time-momentum\nrepresentation to NNLO in chiral perturbation theory. We find $a_\\mu^{ll}({\\rm\nHVP})=(659\\pm 20\\pm 5\\pm 5\\pm 4)\\times 10^{-10}$, where the errors are\nstatistical and estimates of residual uncertainties from taking the continuum\nlimit, scale setting, and truncation of chiral perturbation theory at NNLO. We\ncompare our results with recent ones in the literature.",
        "positive": "Abelian Dominance of Chiral Symmetry Breaking in Lattice QCD: Calculations of the chiral condensate on the lattice using staggered fermions\nand the Lanczos algorithm are presented. Four gauge fields are considered: the\nquenched non-Abelian field, an Abelian projected field, and monopole and photon\nfields further decomposed from the Abelian field. Abelian projection is\nperformed in maximal Abelian gauge and in Polyakov gauge. The results show that\nmonopoles in maximal Abelian gauge largely reproduce the chiral condensate\nvalues of the full non-Abelian theory, in both SU(2) and SU(3) color."
    },
    {
        "anchor": "Structure of the Nucleon and its Excitations: The structure of the ground state nucleon and its finite-volume excitations\nare examined from three different perspectives. Using new techniques to extract\nthe relativistic components of the nucleon wave function, the node structure of\nboth the upper and lower components of the nucleon wave function are\nillustrated. A non-trivial role for gluonic components is manifest. In the\nsecond approach, the parity-expanded variational analysis (PEVA) technique is\nutilised to isolate states at finite momenta, enabling a novel examination of\nthe electric and magnetic form factors of nucleon excitations. Here the\nmagnetic form factors of low-lying odd-parity nucleons are particularly\ninteresting. Finally, the structure of the nucleon spectrum is examined in a\nHamiltonian effective field theory analysis incorporating recent lattice-QCD\ndeterminations of low-lying two-particle scattering-state energies in the\nfinite volume. The Roper resonance of Nature is observed to originate from\nmulti-particle coupled-channel interactions while the first radial excitation\nof the nucleon sits much higher at approximately 1.9 GeV.",
        "positive": "Thermodynamics in 2+1 flavor QCD with improved Wilson quarks by the\n  fixed scale approach: We study thermodynamic properties of 2+1 flavor QCD with improved Wilson\nquarks coupled with the RG improved Iwasaki glue, using the fixed scale\napproach. We present the results for the equation of state, renormalized\nPolyakov loop, and chiral condensate."
    },
    {
        "anchor": "Applying the relativistic quantization condition to a three-particle\n  bound state in a periodic box: Using our recently developed relativistic three-particle quantization\ncondition, we study the finite-volume energy shift of a spin-zero\nthree-particle bound state. We reproduce the result obtained using\nnon-relativistic quantum mechanics by Meissner, Rios and Rusetsky, and\ngeneralize the result to a moving frame.",
        "positive": "Lattice Calculation of the Intrinsic Soft Function and the Collins-Soper\n  Kernel: We calculate the soft function using lattice QCD in the framework of large\nmomentum effective theory incorporating the one-loop perturbative\ncontributions. The soft function is a crucial ingredient in the lattice\ndetermination of light cone objects using transverse-momentum-dependent (TMD)\nfactorization. It consists of a rapidity-independent part called intrinsic soft\nfunction and a rapidity-dependent part called Collins-Soper kernel. We have\nadopted appropriate normalization when constructing the pseudo-scalar meson\nform factor that is needed in the determination of the intrinsic part and\napplied Fierz rearrangement to suppress the higher-twist effects. In the\ncalculation of CS kernel we consider a CLS ensemble other than the MILC\nensemble used in a previous study. We have also compared the applicability of\ndetermining the CS kernel using quasi TMDWFs and quasi TMDPDFs. As an example,\nthe determined soft function is used to obtain the physical TMD wave functions\n(WFs) of pion and unpolarized iso-vector TMD parton distribution functions\n(PDFs) of proton."
    },
    {
        "anchor": "Topological Density and Instantons on a Lattice: We present an update on the study of topological structure of QCD. Issues\naddressed include a comparison between the plaquette and the geometric methods\nof calculating the topological density. We show that the improved gauge action\nbased on sqrt(3) blocking transformation suppresses the formation of\ntopologically charged dislocations with low action. Using a cooling method we\nidentify the instantons' location, estimate their size and density, and\ncalculate the renormalization constant Z_Q for the plaquette method.",
        "positive": "Charmonium, $D_s$ and $D_s^*$ from overlap fermion on DWF configurations: We take a new approach to determine the scale parameter $r_0$, the physical\nmasses of strange and charm quarks through a global fit which incorporates\ncontinuum extrapolation, chiral extrapolation and quark mass interpolation to\nthe lattice data. The charmonium and charm-strange meson spectrum are\ncalculated with overlap valence quarks on $2+1$-flavor domain-wall fermion\ngauge configurations generated by the RBC and UKQCD Collaboration. We use the\nmasses of $D_s$, $D_s^*$ and $J/\\psi$ as inputs and obtain $m_c^{\\overline{\\rm\nMS}}(2\\,{\\rm GeV})=1.110(24)\\,{\\rm GeV}$, $m_s^{\\overline{\\rm MS}}(2\\,{\\rm\nGeV})=0.104(9)\\,{\\rm GeV}$ and $r_0=0.458(11)\\,{\\rm fm}$. Subsequently, the\nhyperfine-splitting of charmonium and $f_{D_s}$ are predicted to be\n$112(5)\\,{\\rm MeV}$ and $254(5)\\,{\\rm MeV}$, respectively."
    },
    {
        "anchor": "Quantum Geometry and Diffusion: We study the diffusion equation in two-dimensional quantum gravity, and show\nthat the spectral dimension is two despite the fact that the intrinsic\nHausdorff dimension of the ensemble of two-dimensional geometries is very\ndifferent from two. We determine the scaling properties of the quantum gravity\naveraged diffusion kernel.",
        "positive": "Lattice determination of the $K \\to (\u03c0\u03c0)_{I=2}$ Decay Amplitude\n  $A_2$: We describe the computation of the amplitude A_2 for a kaon to decay into two\npions with isospin I=2. The results presented in the letter Phys.Rev.Lett. 108\n(2012) 141601 from an analysis of 63 gluon configurations are updated to 146\nconfigurations giving Re$A_2=1.381(46)_{\\textrm{stat}}(258)_{\\textrm{syst}}\n10^{-8}$ GeV and Im$A_2=-6.54(46)_{\\textrm{stat}}(120)_{\\textrm{syst}}10^{-13}$\nGeV. Re$A_2$ is in good agreement with the experimental result, whereas the\nvalue of Im$A_2$ was hitherto unknown. We are also working towards a direct\ncomputation of the $K\\to(\\pi\\pi)_{I=0}$ amplitude $A_0$ but, within the\nstandard model, our result for Im$A_2$ can be combined with the experimental\nresults for Re$A_0$, Re$A_2$ and $\\epsilon^\\prime/\\epsilon$ to give\nIm$A_0/$Re$A_0= -1.61(28)\\times 10^{-4}$ . Our result for Im\\,$A_2$ implies\nthat the electroweak penguin (EWP) contribution to $\\epsilon^\\prime/\\epsilon$\nis Re$(\\epsilon^\\prime/\\epsilon)_{\\mathrm{EWP}} = -(6.25 \\pm\n0.44_{\\textrm{stat}} \\pm 1.19_{\\textrm{syst}}) \\times 10^{-4}$."
    },
    {
        "anchor": "Nf=1 QCD simulation with improved gauge action at finite temperature: We study the deconfinement transition of $N_f=1$ QCD by the hybrid Monte\nCarlo algorithm with Wilson fermions. We calculate the Polyakov loop, its\nsusceptibility and Binder cumulant and use the $\\chi^2$ method to locate the\nphase transition point. Our results are similar to the previous results\nobtained by the multiboson algorithm.",
        "positive": "Lattice Charge Overlap and the Elastic Limit: The results of a lattice simulation of time-separated charge overlap for the\ncharged pion are discussed. The expected result $\\sim {\\rm exp}[-(E_q -\nm_{\\pi})t\\,]$ for large charge density overlap time separations, $t$, is\nclearly visible in the Fourier transform, indicating that the elastic limit can\nbe achieved at low to medium momentum values on present-sized lattices. The\nimplications of this result for direct lattice simulations of hadron structure\nfunctions are discussed and a brief presentation of the lattice formalism is\ngiven."
    },
    {
        "anchor": "Topology and the Dirac Spectrum in Hot QCD: It is known that contrary to expectations, the order parameter of chiral\nsymmetry breaking, the Dirac spectral density at zero virtuality does not\nvanish above the critical temperature of QCD. Instead, the spectral density\ndevelops a pronounced peak at zero. We show that the spectral density in the\npeak has large violations of the expected volume scaling. This anomalous\nscaling and the statistics of these eigenmodes is consistent with them being\nproduced by mixing instanton and antiinstanton zero modes. Consequently, we\nshow that a nonvanishing topological usceptibility implies a finite density of\neigenvalues around zero, which can have implications on the restoration of\nchiral symmetry above the critical temperature.",
        "positive": "Conserving Lattice Gauge Theory for Finite Systems: In this study I develop a novel action for lattice gauge theory for finite\nsystems, which accommodates non-periodic boundary conditions, implements the\nproper integral form of Gauss' law and exhibits an inherently symmetric energy\nmomentum tensor, all while realizing automatic ${\\cal O}(a)$ improvement.\nTaking the modern summation-by-parts formulation for finite differences as\nstarting point and combining it with insight from the finite volume strategies\nof computational electrodynamics I show how the concept of a conserving\ndiscretization can be realized for non-Abelian lattice gauge theory. Major\nsteps in the derivation are illustrated using Abelian gauge theory as example."
    },
    {
        "anchor": "QED at a finite chemical potential: We consider multi-flavor QED on a finite lattice at a finite chemical\npotential and show that the partition function only depends on the variables,\n$(\\frac{\\mu_i}{q_i} -\\frac{\\mu_1}{q_1})$, for $i=2,...$, where $q_i$, $i=1...$\nare integer valued charges of the various flavors and $\\mu_i$, $i=1...$ are the\ndimensional chemical potentials of the various flavors.",
        "positive": "Towards a composite Higgs and a partially composite top quark: We have calculated quantities of interest to a theory of compositeness. The\nlattice model, approximating the candidate theory, is the SU(4) gauge theory\ncoupled to fermions in two color representations. For the composite Higgs, a\ncurrent correlator gives one of the ingredients of the effective Higgs\npotential. For the partially composite top quark, we have hyperbaryon matrix\nelements that govern mixing of the fundamental quark with its heavy composite\npartner. The matrix elements turn out to be so small that the theory is\ndisfavored as a source of a realistic top mass."
    },
    {
        "anchor": "A study of the sign problem for lattice QCD with chemical potential: We study the expectation value of the phase of the fermion determinant for\nWilson lattice fermions with chemical potential. We use quenched SU(3)\nensembles and implement a recently proposed exact dimensional reduction of the\nfermion determinant. Ensembles at several temperatures below and above the\nphase transition are studied and we analyze the role of the quark mass, the\ntemperature, the volume and the topological sectors. We compare our numerical\nresults to predictions from chiral perturbation theory.",
        "positive": "Quenched penguins, the Delta I=1/2 rule, and epsilon'/epsilon: The transformation properties of strong penguin operators under the action of\nthe flavor group change when they are considered as operators in (partially)\nquenched QCD instead of the unquenched theory. An ambiguity arises, which is\nparameterized by new low-energy constants in the effective theory describing\nnon-leptonic kaon decays in the (partially) quenched setting. Here we summarize\nresults of the analysis for the complete set of three-flavor strong penguin\noperators, consisting of products of two left-handed flavor currents, or a\nleft- and a right-handed current. Our results imply that (partially) quenched\nlattice computations of the Delta I=1/2 rule and epsilon'/epsilon are both\naffected by ambiguities intrinsic to the use of the quenched approximation at\nleading order in the chiral expansion. The only exception is the partially\nquenched case with three light sea quarks, consistent with general\nexpectations. We also address the issue of quenched ambiguities in the case of\nan active charm, correcting and extending that in Phys. Rev. D 74, 014509\n(2006)."
    },
    {
        "anchor": "Exceptional Configurations with the Clover Action: We study exceptional modes of both the Wilson and the clover action in order\nto understand why quenched clover spectroscopy suffers so severely from\nexceptional configurations. We show that a large clover coefficient can make\nthe exceptional modes extremely localized and thus very sensitive to short\ndistance fluctuations. We contrast this with the case of the Wilson action\nwhere exceptional modes correspond to large instantons. These modes are broadly\nextended and suffer much less from discretization errors.",
        "positive": "Decay constants and spectroscopy of mesons in lattice QCD using\n  domain-wall fermions: We report results of masses and decay constants of light and charmed\npseudo-scalar mesons using lattice QCD with M\\\"obius domain-wall fermions.\nUsing this formulation we are able to compute pseudo-scalar decay constants\nthrough the pseudo-scalar density operator as well as with the axial-vector\ncurrent. Results are shown from several lattice spacings and pion masses\nbetween 230 MeV and 500 MeV. We present an analysis of these results at\ndifferent quark masses to show the chiral properties of the light mesons masses\nand decay constants."
    },
    {
        "anchor": "Electromagnetic corrections to the leptonic decay rates of charged\n  pseudoscalar mesons: lattice results: Electromagnetic effects in the leptonic decay rates $\\pi^+ \\to \\mu^+ \\nu$ and\n$K^+ \\to \\mu^+ \\nu$ are evaluated for the first time on the lattice. Following\na method recently proposed in Ref. [1] the emission of virtual photons at\nleading order in the electromagnetic coupling is evaluated on the lattice and\nthe infrared divergence computed for a point-like meson at finite lattice\nvolume is subtracted. The physical decay rate is then obtained by adding the\nemission of real and virtual photons regularised with a photon mass. Using the\ngauge ensembles produced by the European Twisted Mass Collaboration with $N_f =\n2 + 1 + 1$ dynamical quarks the feasibility of our approach is demonstrated.\nPreliminary results for the electromagnetic corrections to charged (neutral)\npion and kaon masses as well as to the leptonic decay rates of charged pions\nand kaons are presented.",
        "positive": "Complex Langevin Dynamics and Supersymmetric Quantum Mechanics: Using complex Langevin method we probe the possibility of dynamical\nsupersymmetry breaking in supersymmetric quantum mechanics models with complex\nactions. The models we consider are invariant under the combined operation of\nparity and time reversal, in addition to supersymmetry. When actions are\ncomplex traditional Monte Carlo methods based on importance sampling fail.\nModels with dynamically broken supersymmetry can exhibit sign problem due to\nthe vanishing of the partition function. Complex Langevin method can\nsuccessfully evade the sign problem. Our simulations suggest that complex\nLangevin method can reliably predict the absence or presence of dynamical\nsupersymmetry breaking in these one-dimensional models with complex actions."
    },
    {
        "anchor": "Beyond Generalized Eigenvalues in Lattice Quantum Field Theory: Two analysis techniques, the generalized eigenvalue method (GEM) or Prony's\n(or related) method (PM), are commonly used to analyze statistical estimates of\ncorrelation functions produced in lattice quantum field theory calculations.\nGEM takes full advantage of the matrix structure of correlation functions but\nonly considers individual pairs of time separations when much more data exists.\nPM can be applied to many time separations and many individual matrix elements\nsimultaneously but does not fully exploit the matrix structure of the\ncorrelation function. We combine both these methods into a single framework\nbased on matrix polynomials. As these algebraic methods are well known for\nproducing extensive spectral information about statistically-noisy data, the\nmethod should be paired with some information criteria, like the recently\nproposed Bayesean model averaging.",
        "positive": "Towards a Lattice Calculation of the Nucleon Structure Functions: We have initiated a programme to compute the lower moments of the unpolarised\nand polarised deep inelastic structure functions of the nucleon in the quenched\napproximation. We review our progress to date."
    },
    {
        "anchor": "3D N = 1 SYM Chern-Simons theory on the Lattice: We present a method to implement 3-dimensional N = 1 SUSY Yang-Mills theory\n(a theory with two real supercharges containing gauge fields and an adjoint\nMajorana fermion) on the lattice, including a way to implement the Chern-Simons\nterm present in this theory. At nonzero Chern-Simons number our implementation\nsuffers from a sign problem which will make the numerical effort grow\nexponentially with volume. We also show that the theory with vanishing\nChern-Simons number is anomalous; its partition function identically vanishes.",
        "positive": "High precision single-cluster Monte Carlo measurement of the critical\n  exponents of the classical 3D Heisenberg model: We report measurements of the critical exponents of the classical\nthree-dimensional Heisenberg model on simple cubic lattices of size $L^3$ with\n$L$ = 12, 16, 20, 24, 32, 40, and 48. The data was obtained from a few long\nsingle-cluster Monte Carlo simulations near the phase transition. We compute\nhigh precision estimates of the critical coupling $K_c$, Binder's parameter\n$U^* and the critical exponents $\\nu,\\beta / \\nu, \\eta$, and $\\alpha / \\nu$,\nusing extensively histogram reweighting and optimization techniques that allow\nus to keep control over the statistical errors. Measurements of the\nautocorrelation time show the expected reduction of critical slowing down at\nthe phase transition as compared to local update algorithms. This allows\nsimulations on significantly larger lattices than in previous studies and\nconsequently a better control over systematic errors in finite-size scaling\nanalyses."
    },
    {
        "anchor": "Hyperons in thermal QCD: A lattice view: The hadron resonance gas (HRG) is a widely used description of matter under\nextreme conditions, e.g. in the context of heavy-ion phenomenology. Commonly\nused implementations of the HRG employ vacuum hadron masses throughout the\nhadronic phase and hence do not include possible in-medium effects. Here we\ninvestigate this issue, using nonperturbative lattice simulations employing the\nFASTSUM anisotropic Nf=2+1 ensembles. We study the fate of octet and decuplet\nbaryons as the temperature increases, focussing in particular on the positive-\nand negative-parity groundstates. While the positive-parity groundstate masses\nare indeed seen to be temperature independent, within the error, a strong\ntemperature dependence is observed in the negative-parity channels. We give a\nsimple parametrisation of this and formulate an in-medium HRG, which is\nparticularly effective for hyperons. Parity doubling is seen to emerge in the\ndeconfined phase at the level of correlators, with a noticeable effect of the\nheavier s quark. Channel dependence of this transition is analysed.",
        "positive": "Neutrinoless Double Beta Decay from Lattice QCD: The Short-Distance\n  $\u03c0^-\\rightarrow\u03c0^+ e^- e^-$ Amplitude: This work presents a determination of potential short-distance contributions\nto the unphysical $\\pi^-\\rightarrow\\pi^+ e^- e^-$ decay through lattice QCD\ncalculations. The hadronic contributions to the transition amplitude are\ndescribed by the pion matrix elements of five Standard Model Effective Field\nTheory operators, which are computed on five ensembles of domain-wall fermions\nwith $N_f = 2 + 1$ quark flavors with a range of heavier-than-physical values\nof the light quark masses. The matrix elements are extrapolated to the\ncontinuum, physical light-quark mass, and infinite volume limit using a\nfunctional form derived in chiral Effective Field Theory ($\\chi\\mathrm{EFT}$).\nThis extrapolation also yields the relevant low-energy constants of\n$\\chi\\mathrm{EFT}$, which are necessary input for $\\chi\\mathrm{EFT}$\ncalculations of neutrinoless double beta decay of nuclei."
    },
    {
        "anchor": "Highly anisotropic lattices for Yang-Mills theory: In this conference proceeding, we investigate the physical anisotropy in\nterms of the temporal and spatial lattice spacings in relation to the bare\nparameters of SU(2) pure gauge theory using Wilson gradient flow. Anisotropic\nlattices have a wide range of applications, from thermodynamic calculations in\nQCD to very recent real-time simulations using the complex Langevin method. We\nfind an almost linear relationship between the bare and renormalized\nanisotropy. Using a parametrization that includes nonlinear effects and was\nearlier proposed for SU(3) theory, we obtain a good description of the coupling\ndependence of the anisotropy with only two fitting parameters. Our observation\nof an approximately linear relationship and this parametrization should\nstrongly reduce the computational effort of anisotropic lattice calculations in\nthe future.",
        "positive": "The nucleon axial charge from lattice QCD with controlled errors: We report on our calculation of the nucleon axial charge gA in QCD with two\nflavours of dynamical quarks. A detailed investigation of systematic errors is\nperformed, with a particular focus on contributions from excited states to\nthree-point correlation functions. The use of summed operator insertions allows\nfor a much better control over such contamination. After performing a chiral\nextrapolation to the physical pion mass, we find gA=1.223 +/- 0.063 (stat)\n+0.035 -0.060 (syst), in good agreement with the experimental value."
    },
    {
        "anchor": "Investigating a (3+1)D Topological $\u03b8$-Term in the Hamiltonian\n  Formulation of Lattice Gauge Theories for Quantum and Classical Simulations: Quantum technologies offer the prospect to efficiently simulate sign-problem\nafflicted regimes in lattice field theory, such as the presence of topological\nterms, chemical potentials, and out-of-equilibrium dynamics. In this work, we\nderive the (3+1)D topological $\\theta$-term for Abelian and non-Abelian lattice\ngauge theories in the Hamiltonian formulation, paving the way towards\nHamiltonian-based simulations of such terms on quantum and classical computers.\nWe further study numerically the zero-temperature phase structure of a (3+1)D\nU(1) lattice gauge theory with the $\\theta$-term via exact diagonalization for\na single periodic cube. In the strong coupling regime, our results suggest the\noccurrence of a phase transition at constant values of $\\theta$, as indicated\nby an avoided level-crossing and abrupt changes in the plaquette expectation\nvalue, the electric energy density, and the topological charge density. These\nresults could in principle be cross-checked by the recently developed (3+1)D\ntensor network methods and quantum simulations, once sufficient resources\nbecome available.",
        "positive": "Bounds on free energy in QCD: We derive some exact bounds on the free energy $W(J)$ in QCD, where $J_\\mu^b$\nis a source for the gluon field $A_\\mu^b$ in the minimal Landau gauge, and\n$W(J)$ is the generating functional of connected gluon correlators. Among other\nresults, we show that for a static source $J(x) = h$ the free energy vanishes,\n$W(h) = 0$, together with its first derivative, ${\\partial W(h) \\over \\partial\nh} = 0,$ for all $h$, no matter how strong. Thus the system does not respond to\na static color probe. We also present numerical evaluations of the free energy\n$W(J)$ and find that the bounds are well satisfied and in fact undersaturated."
    },
    {
        "anchor": "Staggered Chiral Perturbation Theory for Neutral B Mixing: I describe a calculation of B meson mixing at one-loop in staggered chiral\nperturbation theory, for the complete set of Standard Model and\nbeyond-the-Standard Model operators. The particular lattice representation of\nthe continuum operators used by the Fermilab Lattice/MILC collaborations (and\nearlier by the HPQCD collaboration) turns out to be important, and results in\nthe presence of \"wrong-spin\" operators, whose contributions however vanish in\nthe continuum limit. The relation between staggered and naive fermions also\nplays a key role.",
        "positive": "Isospin symmetry breaking effects in the pion and nucleon masses: We investigate the electromagnetic mass splittings in the pseudoscalar meson\nand nucleon systems by combining 2+1 flavor domain wall fermion gauge\nconfigurations, generated by the RBC and UKQCD collaborations, and quenched,\nnon-compact, lattice QED configurations. We analyze finite volume effects by\nusing $16^3\\times 32$ and $24^3\\times 64$ lattices."
    },
    {
        "anchor": "Gluon contributions to the pion mass and light cone momentum fraction: We calculate the matrix elements of the gluonic contributions to the\nenergy-momentum tensor for a pion of mass 600 < Mpi < 1100 MeV in quenched\nlattice QCD. We find that gluons contribute (37 +/- 8 +/- 12)% of the pion's\nlight cone momentum. The bare matrix elements corresponding to the trace\nanomaly contribution to the pion mass are also obtained. The discretizations of\nthe energy-momentum tensor we use have other promising applications, ranging\nfrom calculating the origin of hadron spin to QCD thermodynamics.",
        "positive": "Lattice four-dimensional N=4 SYM is practical: We show that nonperturbative lattice studies of four-dimensional N=4\nSuper-Yang-Mills are within reach. We use Ginsparg-Wilson fermions to avoid\ngluino masses and an exact implementation of the (chiral) $R$-symmetry, which\ngreatly limits the number of counterterms that must be fine-tuned. Only bosonic\noperators require fine tuning, so all tunings can be done ``offline'' by a\nFerrenberg-Swendsen type reweighting. We show what measurables can be used to\nperform the tuning."
    },
    {
        "anchor": "Vector Meson Mass Corrections at O(a^2) in PQChPT with Wilson and\n  Ginsparg-Wilson quarks: We derive the mixed as well as unmixed lattice heavy meson chiral Lagrangian\nup to order O(a^2), with Wilson and Ginsparg-Wilson fermions. We consider two\nflavor partially quenched QCD and calculate vector meson mass corrections up to\norder O(a^2), including the corrections associated with the violation of\nrotational O(4) symmetry down to the hypercubic group. Our calculations also\ninclude the one-loop, phenomenological contribution from the \\rho -> \\pi\\pi\ndecay channel. The final result is a chiral-continuum extrapolation formula\nwith model dependent coefficients from which one can recover the physical \\rho\nmeson mass from the large amount of current lattice data. As a verification of\nour result, the chiral-continuum extrapolation formula is compared with that\nused in numerical simulations.",
        "positive": "Confinement made simple in the Coulomb gauge: In Gribov's scenario in Coulomb gauge, confinement of color charge is due to\na long-range instantaneous color-Coulomb potential V(R). This may be determined\nnumerically from the instantaneous part of the gluon propagator D_{44, inst} =\nV(R) \\delta(t). Confinement of gluons is reflected in the vanishing at k = 0 of\nthe equal-time three-dimensionally transverse would-be physical gluon\npropagator D^{tr}(k). We present exact analytic results on D_{44} and D^{tr}\n(which have also been investigated numerically, A. Cucchieri, T. Mendes, and D.\nZwanziger, this conference), in particular the vanishing of D^{tr}(k) at k = 0,\nand the determination of the running coupling constant from x_0 g^2(k) = k^2\nD_{44, inst}, where x_0 = 12N/(11N-2N_f)."
    },
    {
        "anchor": "On the definition and interpretation of a static quark anti-quark\n  potential in the colour-adjoint channel: We study possibilities to define a static quark anti-quark pair in a\ncolour-adjoint orientation based on Wilson loops with generator insertions,\nusing both lattice QCD and leading order perturbation theory in various gauges.\nNon-perturbatively, the only way to obtain non-zero results while maintaining\npositivity of the Hamiltonian is by some form of temporal gauge. In this case\nthe correlator is equivalent to a gauge invariant correlation function of a\nstatic quark anti-quark pair and a static adjoint quark, the resulting\nthree-point potential is attractive. Saturating open colour indices with colour\nmagnetic fields instead also leads to a gauge invariant correlator. However\nthis object is found to couple to the singlet sector only. There appears to be\nno lattice observable that reproduces the repulsive adjoint potential predicted\nby perturbation theory in Lorenz or Coulomb gauges.",
        "positive": "$\u03c1$ meson decay on asymmetrical lattices: We present a lattice QCD calculation of the characteristics of the $\\rho$\nmeson decay. The study is carried out on spatially asymmetric boxes using\nnHYP-smeared clover fermions in the quenched approximation. The resonance mass\nand coupling constant are calculate using the P-wave scattering phaseshifts, of\nthe isospin I=1 two-pion system. We use pion masses m_{\\pi}= 418 MeV and\nm_{\\pi}=312 MeV. In both cases, the $\\rho$ decay is kinematically feasible. We\nwork on lattice sizes N_z X 24^2 X 48 with lattice spacing a=0.1 fm and\nN_z=24,30,34,48."
    },
    {
        "anchor": "Phase structure of finite temperature QCD in the heavy quark region: We study the quark mass dependence of the finite temperature QCD phase\ntransition in the heavy quark region using an effective potential defined\nthrough the probability distribution function of the average plaquette.\nPerforming a simulation of SU(3) pure gauge theory, we first confirm that the\ndistribution function has two peaks indicating that the phase transition is of\nfirst order in the heavy quark limit, while the first order transition turns\ninto a crossover as the quark mass decreases from infinity, where the mass\ndependence of the distribution function is evaluated by the reweighting method\ncombined with the hopping parameter expansion. We determine the endpoint of the\nfirst order transition region for N_f=1, 2, 3 and 2+1 cases. The quark mass\ndependence of the latent heat is also evaluated in the first order transition\nregion.",
        "positive": "Light quark masses using domain wall fermions: We compute the one-loop self-energy correction to the massive domain wall\nquark propagator. Combining this calculation with simulations at several gauge\ncouplings, we estimate the strange quark mass in the continuum limit. The\nperturbative one-loop mass renormalization is comparable to that for Wilson\nquarks and considerably smaller than that for Kogut-Susskind quarks. Also,\nscaling violations appear mild in comparison to other errors at present. Given\ntheir good chiral behavior and these features, domain wall quarks are\nattractive for evaluating the light quark masses. Our preliminary quenched\nresult is m_s(2 GeV) = 82(15) MeV in the ${\\bar{MS}}$ scheme."
    },
    {
        "anchor": "Study of thermal SU(3) supersymmetric Yang-Mills theory and\n  near-conformal theories from the gradient flow: We compute the renormalization group flow of the mass anomalous dimension in\nadjoint QCD with $N_{f}=1$, $3/2$, and 2 Dirac fermions, using the gradient\nflow. Preliminary results are in agreement with at least a near-conformal\nscenario in all cases. At the largest flavor numbers we obtain the strongest\nindication for an IR conformal fixed point scenario. Moreover, we provide\nresults for the thermal phase transitions in SU(3) supersymmetric Yang-Mills\ntheory. We find hints for a connection between chiral and center symmetries in\nterms of a single first order phase transition where chiral symmetry is\nrestored and center symmetry gets broken.",
        "positive": "The SU(2) $\\times$ SU(2) chiral spin model in terms of SO(3) and Z$_2$\n  variables: vortices and disorder: We rewrite the two-dimensional SU(2)$\\times$ SU(2) chiral spin model in terms\nof SO(3) and {\\bf Z}$_2$ degrees of freedom. The transformation, which is\nmotivated by a similar representation of the corresponding lattice gauge theory\nin higher dimensions, exhibits the presence of dynamical SO(3) vortices and\nassociated strings. We present arguments that (pairs of) SO(3) vortices with\nlong strings play a crucial role in disordering the spin system at arbitrarily\nlow temperatures."
    },
    {
        "anchor": "Results From The UKQCD Parallel Tempering Project: We present results from our study of the Parallel Tempering algorithm. We\nexamine the swapping acceptance rate of a twin subensemble PT system. We use\naction matching technology in an attempt to maximise the swap acceptance rate.\nWe model the autocorrelation times within Parallel Tempering ensembles in terms\nof autocorrelation times from Hybrid Monte Carlo. We present estimates for the\nautocorrelation times of the plaquette operator.",
        "positive": "Effective Potential in the Strong-coupling Lattice QCD with\n  Next-to-Next-to-Leading Order Effects: We derive an analytic expression of the effective potential at finite\ntemperature (T) and chemical potential (mu) in the strong-coupling lattice QCD\nfor color SU(3) including next-to-next-to-leading order (NNLO) effects in the\nstrong coupling expansion. NNLO effective action terms are systematically\nevaluated in the leading order of the large dimensional (1/d) expansion, and\nare found to come from some types of connected two plaquette configurations. We\napply the extended Hubbard-Stratonovich transformation and a gluonic dressed\nfermion technique to the effective action, and obtain the effective potential\nas a function of T, mu, and two order parameters; chiral condensate and a\nvector potential field. The next-to-leading order (NLO) and NNLO effects result\nin modifications of the wave function renormalization factor, quark mass and\nchemical potential. We find that T_{c,mu=0} and mu_{c,T=0} are similar to the\nNLO results, whereas the position of the critical point is sensitive to NNLO\ncorrections."
    },
    {
        "anchor": "Lellouch-L\u00fcscher factor for the $K\\to 3\u03c0$ decays: We derive an explicit expression for the Lellouch-L\\\"uscher (LL) factor in\nthe $K\\to 3\\pi$ decays at leading order (without derivative couplings). Several\nimportant technical details are addressed, like a proper decomposition into the\nisospin amplitudes, the choice of a minimal set of effective couplings and the\nrenormalization, as well as the algorithm for the solution of the pertinent\nFaddeev equations in the infinite volume which is based on the contour\ndeformation method. Most importantly, our numerical results demonstrate that\nthe three-body force contributes very little to the LL factor. This result\npaves the way for the study of the $K\\to 3\\pi$ decays on the lattice.",
        "positive": "Effects of the quark field on the ghost propagator of Lattice Landau\n  Gauge QCD: Infrared features of the ghost propagator of color diagonal and color\nantisymmetric ghost propagator of quenched SU(2) and quenched SU(3) are\ncompared with those of unquenched Kogut-Susskind fermion SU(3) lattice Landau\ngauge.\n  We compare 1) the fluctuation of the ghost propagator, 2) the ghost\ncondensate parameter $v$ of the local composite operator (LCO) approach and 3)\nthe Binder cumulant of color anti-symmetric ghost propagator between quenched\nand unquenched configurations."
    },
    {
        "anchor": "Gauge Invariant SO(3) - Z2 Monopoles as Possible Source of Confinement\n  in SU(2) Lattice Gauge Theory: A gauge invariant procedure for extracting combined SO(3)-Z2 monopoles in\npositive-plaquette SU(2) lattice gauge theory is shown. When these monopoles\nare eliminated through a constraint, the theory deconfines for all $\\beta$ on\n$12^4$ and $20^4$ lattices even in the strong coupling limit, despite a rather\nstrong average plaquette of around 0.64. This corresponds to an effective\nWilson $\\beta$ of 2.45, at which Wilson-action lattices would be far into the\nconfining region. This suggests that Wilson-action confinement may be a\nstrong-coupling lattice artifact; the continuum limit may not confine.",
        "positive": "Chiral Magnetism of the Nucleon: We study the quark mass expansion of the magnetic moments of the nucleon in a\nchiral effective field theory including nucleons, pions and delta resonances as\nexplicit degrees of freedom. We point out that the usual powercounting applied\nso far to this problem misses important quark mass structures generated via an\nintermediate isovector M1 nucleon-delta transition. We propose a modified\npowercounting and compare the resulting chiral extrapolation function to\navailable (quenched) lattice data. The extrapolation is found to work\nsurprisingly well, given that the lattice data result from rather large quark\nmasses. Our calculation raises the hope that extrapolations of lattice data\nutilizing chiral effective field theory might be applicable over a wider range\nin quark masses than previously thought, and we discuss some open questions in\nthis context. Furthermore, we observe that within the current lattice data\nuncertainties the extrapolations presented here are consistent with the Pade\nfit ansatz introduced by the Adelaide group a few years ago."
    },
    {
        "anchor": "Hadronic interactions and nuclear physics: I give an overview of efforts in the last year to calculate interactions\namong hadrons using lattice QCD. Results discussed include the extraction of\nlow-energy phase shifts and three-body interactions, and the study of pion and\nkaon condensation. A critical appraisal is offered of recent attempts to\ncalculate nucleon-nucleon and nucleon-hyperon potentials on the lattice.",
        "positive": "Onset Transition to Cold Nuclear Matter from Lattice QCD with Heavy\n  Quarks to $\u03ba^4$: We present results of our ongoing studies of an effective three-dimensional\ntheory of thermal lattice QCD with heavy Wilson quarks. This is done by\ncombined strong coupling and hopping parameter expansions. The full quark\ndeterminant of four dimensional lattice QCD is expanded in orders of the\nhopping parameter $\\kappa$, the dimensional reduction is achieved by\nintegrating over the spatial links. We present the calculation of the effective\ntheory through order $\\kappa^nu^m$ with $n+m=4$. This theory is then used to\nsimulate heavy quarks near the cold and dense limit. For nonzero chemical\npotential the theory suffers from a sign problem, wich is avoided by employing\nstochastical quantisation. Continuum extrapolated results for the onset of\nnuclear matter are shown and the region of convergence of the effective theory\nis discussed."
    },
    {
        "anchor": "Light hadron spectroscopy in quenched lattice QCD with chiral\n  Fixed-Point fermions: The classically perfect Fixed-Point fermion action for lattice QCD, a highly\nimproved discretization of the continuum theory that preserves chiral symmetry,\nis constructed in this thesis and a parallel work by T. Jorg. In the framework\nof the BGR collaboration, we perform studies in quenched light hadron\nspectroscopy with this new action in order to examine its chiral and scaling\nproperties and investigate in detail the chiral limit of pseudoscalar mesons.\nTopological finite-volume artifacts are identified and removed, and the\ncoefficient of the quenched chiral logarithm is measured. The results show that\nthe Fixed-Point action allows to simulate at quark masses corresponding to\nPS/V<0.3, has small scaling violations in hadron masses and reproduces the\ncontinuum energy-momentum dispersion relation very well.",
        "positive": "Twisted mass ensemble generation on GPU machines: We present how we ported the Hybrid Monte Carlo implementation in the tmLQCD\nsoftware suite to GPUs through offloading its most expensive parts to the QUDA\nlibrary. We discuss our motivations and some of the technical challenges that\nwe encountered as we added the required functionality to both tmLQCD and QUDA.\nWe further present some performance details, focussing in particular on the\nusage of QUDA's multigrid solver for poorly conditioned light quark monomials\nas well as the multi-shift solver for the non-degenerate strange and charm\nsector in $N_f=2+1+1$ simulations using twisted mass clover fermions, comparing\nthe efficiency of state-of-the-art simulations on CPU and GPU machines. We also\ntake a look at the performance-portability question through preliminary tests\nof our HMC on a machine based on AMD's MI250 GPU, finding good performance\nafter a very minor additional porting effort. Finally, we conclude that we\nshould be able to achieve GPU utilisation factors acceptable for the current\ngeneration of (pre-)exascale supercomputers with subtantial efficiency\nimprovements and real time speedups compared to just running on CPUs. At the\nsame time, we find that future challenges will require different approaches\nand, most importantly, a very significant investment of personnel for software\ndevelopment."
    },
    {
        "anchor": "Hadron spectrum, quark masses and decay constants from light overlap\n  fermions on large lattices: We present results from a simulation of quenched overlap fermions with\nL\\\"uscher-Weisz gauge field action on lattices up to $24^3 48$ and for pion\nmasses down to $\\approx 250$ MeV. Among the quantities we study are the pion,\nrho and nucleon masses, the light and strange quark masses, and the pion decay\nconstant. The renormalization of the scalar and axial vector currents is done\nnonperturbatively in the $RI-MOM$ scheme. The simulations are performed at two\ndifferent lattice spacings, $a \\approx 0.1$ fm and $\\approx 0.15$ fm, and on\ntwo different physical volumes, to test the scaling properties of our action\nand to study finite volume effects. We compare our results with the predictions\nof chiral perturbation theory and compute several of its low-energy constants.\nThe pion mass is computed in sectors of fixed topology as well.",
        "positive": "Topological Charge Correlators, Spectral Bounds, and Contact Terms: The structure of topological charge fluctuations in the QCD vacuum is\nstrongly restricted by the spectral negativity of the Euclidean 2-point\ncorrelator for $x\\neq 0$ and the presence of a positive contact term. Some\nexamples are considered which illustrate the physical origin of these\nproperties."
    },
    {
        "anchor": "Non-perturbative construction of 2D and 4D supersymmetric Yang-Mills\n  theories with 8 supercharges: In this paper, we consider two-dimensional N=(4,4) supersymmetric Yang-Mills\n(SYM) theory and deform it by a mass parameter M with keeping all supercharges.\nWe further add another mass parameter m in a manner to respect two of the eight\nsupercharges and put the deformed theory on a two-dimensional square lattice,\non which the two supercharges are exactly preserved. The flat directions of\nscalar fields are stabilized due to the mass deformations, which gives discrete\nminima representing fuzzy spheres. We show in the perturbation theory that the\nlattice continuum limit can be taken without any fine tuning. Around the\ntrivial minimum, this lattice theory serves as a non-perturbative definition of\ntwo-dimensional N=(4,4) SYM theory. We also discuss that the same lattice\ntheory realizes four-dimensional N = 2 U(k) SYM on R^2 x (Fuzzy R^2) around the\nminimum of k-coincident fuzzy spheres.",
        "positive": "Lattice QCD matrix elements for the ${B_s^0-\\bar{B}_s^0}$ width\n  difference beyond leading order: Predicting the $B_s^0-\\bar{B}_s^0$ width difference $\\Delta\\Gamma_s$ relies\non the heavy quark expansion and on hadronic matrix elements of $\\Delta B=2$\noperators. We present the first lattice QCD results for matrix elements of the\ndimension-7 operators $R_{2,3}$ and linear combinations $\\tilde{R}_{2,3}$ using\nnonrelativistic QCD for the bottom quark and a highly improved staggered quark\n(HISQ) action for the strange quark. Computations use MILC ensembles of gauge\nfield configuations with $2+1+1$ flavors of sea quarks with the HISQ\ndiscretization, including lattices with physically light up/down quark masses.\nWe discuss features unique to calculating matrix elements of these operators\nand analyze uncertainties from series truncation, discretization, and quark\nmass dependence. Finally we report the first Standard Model determination of\n$\\Delta\\Gamma_s$ using lattice QCD results for all hadronic matrix elements\nthrough $\\mathcal{O}(1/m_b)$. The main result of our calculations yields the\n$1/m_b$ contribution $\\Delta \\Gamma_{1/m_b} = -0.022(10)~\\mathrm{ps}^{-1}$.\nAdding this to the leading order contribution, the Standard Model prediction is\n$\\Delta \\Gamma_s = 0.092(14)~\\mathrm{ps}^{-1}$."
    },
    {
        "anchor": "Dynamical simulation of N=1 supersymmetric Yang-Mills theory with domain\n  wall fermions: We present results from a numerical study of N=1 supersymmetric Yang-Mills\ntheory using domain wall fermions. In this particular lattice formulation of\nthe theory, supersymmetry is expected to emerge accidentally in the continuum\nand chiral limits without any fine-tuning of operators. Dynamical simulations\nwere performed for the gauge group SU(2) on 8^3x8 and 16^3x32 lattice\nspace-time volumes and at three different values of the coupling: beta = 2.3,\n2.353 and 2.4. Results from this study include measurements of the static\npotential, residual mass, and a chirally extrapolated value for the gluino\ncondensate at beta=2.3. In addition to these, we study the low lying\neigenvalues and eigenvectors of the five dimensional Hermitian domain-wall\nfermion Dirac operator and present evidence that, for the choice of parameters\nunder investigation, features of the spectrum appear qualitatively consistent\nwith strong coupling and the presence of a large residual mass. From the five\ndimensional eigenvalues we explore the possibility of using the Banks-Casher\nrelation to determine an independent value for the gluino condensate in the\nchiral limit.",
        "positive": "The generalized fermion-bag approach: We present a new approach to some four-fermion lattice field theories which\nwe call the generalized fermion bag approach. The basic idea is to identify\nunpaired fermionic degrees of freedom that cause sign problems and collect them\nin a bag. Paired fermions usually act like bosons and do not lead to sign\nproblems. A resummation of all unpaired fermion degrees of freedom inside the\nbag is sufficient to solve the fermion sign problem in a variety of interesting\ncases. Using a concept of duality we then argue that the size of the fermion\nbags is small both at strong and weak couplings. This allows us to construct\nefficient algorithms in both these limits. Using the fermion bag approach, we\nstudy the quantum phase transition of the 3D massless lattice Thirrring model\nwhich is of interest in the context of Graphene. Using our method we are able\nto solve the model on lattices as large as $40^3$ with moderate computational\nresources. We obtain the precise location of the quantum critical point and the\nvalues of the critical exponents through this study."
    },
    {
        "anchor": "QCD-like theories with many fermions: magnetic plasma and unusual\n  confinements: This comment-style letter represents a part of my talks on new developments\nin lattice QCD. While it does not contain any new results, it containes some\ntheoretical ideas and comparisons which, I think, are not yet widely discussed\nin the lattice community. We point out that for $N_f\\sim 10$ one can study a\nplasma phase which is much more \"magnetic dominated\" than for small $N_f$. We\nalso suggest certain tests/measurements to check if \"unusual confinement\"\nphases are or are not realized in this region.",
        "positive": "Cottingham formula for the electromagnetic self-energy contribution to\n  M_p - M_n: We provide an update of the determination of the electromagnetic self-energy\ncontribution to M_p - M_n based upon Cottingham's Formula. A technical\noversight in the literature is uncovered: the application of the Cottingham\nFormula requires the use of a subtracted dispersion integral; an argument to\nevade the subtraction function was presented; the argument was based on false\nassumptions about the scaling violations of the parton model, a point first\nmentioned by J. C. Collins. We elucidate this point and utilize low-energy\neffective theory to relate the unknown subtraction function to the nucleon\nisovector magnetic polarizability. This allows us to provide the first reliable\ndetermination of dM = 1.30(03)(47) MeV [1]."
    },
    {
        "anchor": "Application of the $O(N)$-Hyperspherical Harmonics to the Study of the\n  Continuum Limits of One-Dimensional $\u03c3$-Models and to the Generation of\n  High-Temperature Expansions in Higher Dimensions: In this talk we present the exact solution of the most general\none-dimensional $O(N)$-invariant spin model taking values in the sphere\n$S^{N-1}$, with nearest-neighbour interactions, and we discuss the possible\ncontinuum limits. All these results are obtained using a high-temperature\nexpansion in terms of hyperspherical harmonics. Applications in higher\ndimensions of the same technique are then discussed.",
        "positive": "Chiral gauge theories on the lattice without gauge fixing?: We discuss two proposals for a non-perturbative formulation of chiral gauge\ntheories on the lattice. In both cases gauge symmetry is broken by the\nregularization. We aim at a dynamical restoration of symmetry. If the gauge\nsymmetry breaking is not too severe this procedure could lead in the continuum\nlimit to the desired chiral gauge theory."
    },
    {
        "anchor": "Algorithm Shootout: R versus RHMC: We present initial results comparing the RHMC and R algorithms on large\nlattices with small quark masses using chiral fermions. We also present results\nconcerning staggered fermions near the deconfinement/chiral phase transition.\nWe find that the RHMC algorithm not only eliminates the step-size error of the\nR algorithm, but is also considerably more efficient. We discuss several\npossibilities for further improvement to the RHMC algorithm.",
        "positive": "A simple model for a scalar two-point correlator in the presence of a\n  resonance: We present a simple toy model for a scalar-isoscalar two-point correlator,\nwhich can serve as a testing ground for the extraction of resonance parameters\nfrom Lattice QCD calculations. We discuss in detail how the model correlator\nbehaves when it is restricted to a finite spatial volume, and how the\nfinite-volume data can be used to reconstruct the spectral function of the\ncorrelator in the infinite volume, which allows to extract properties of the\nresonance from such data."
    },
    {
        "anchor": "Mesonic correlators at non-zero baryon chemical potential: In order to study the fate of mesons in thermal QCD at finite baryon chemical\npotential, we consider light mesonic correlation functions using the Taylor\nexpansion to ${\\cal O}((\\mu/T)^2)$, in both the hadronic and quark-gluon plasma\nphases. We use the FASTSUM anisotropic fixed-scale lattices with $N_f = 2+1$\nflavours of Wilson fermion. We find that mesonic correlators are sensitive to\nfinite-density corrections and that the second-order terms indicate the chiral\ncrossover in the vector and axial-vector channels.",
        "positive": "Large Field Cutoffs in Lattice Gauge Theory: In pure gauge SU(3) near beta = 6, weak and strong coupling expansions break\ndown and the MC method seems to be the only practical alternative. We discuss\nthe possibility of using a modified version of perturbation theory which relies\non a large field cutoff and has been successfully applied to the double-well\npotential (Y. M., PRL 88 141601). Generically, in the case of scalar field\ntheory, the weak coupling expansion is unable to reproduce the exponential\nsuppression of the large field configurations. This problem can be solved by\nintroducing a large field cutoff. The value of this cutoff can be chosen to\nreduce the discrepancy with the original problem. This optimization can be\napproximately performed using the strong coupling expansion and bridges the gap\nbetween the two expansions. We report recent attempts to extend this procedure\nfor SU(3) gauge theory on the lattice. We compare gauge invariant and gauge\ndependent (in the Landau gauge) criteria to sort the configurations into\n``large-field'' and ``small-field'' configurations. %We discuss the effects of\ndiscarding the large field configurations. We discuss the convergence of\nlattice perturbation theory and the way it can be modified in order to obtain\nresults similar to the scalar case."
    },
    {
        "anchor": "Hadronic Molecules in Lattice QCD: An adiabatic approximation is used to derive the binding potential between\ntwo heavy-light mesons in quenched SU(2)-colour lattice QCD. Analysis of the\nmeson-meson system shows that the potential is attractive at short- and\nmedium-range. The numerical data is consistent with the Yukawa model of pion\nexchange",
        "positive": "Static quark anti-quark free and internal energy in 2-flavor QCD: We study the change in free and internal energy due to the presence of a\nheavy quark anti-quark pair in a thermal heat bath in QCD with 2-flavors of\nstaggered quarks at finite temperature. We discuss string breaking below as\nwell as screening above the transition. Similarities and differences to the\nquenched case are discussed."
    },
    {
        "anchor": "The Landau gauge gluon propagator: Gribov problem and finite-size\n  effects: The SU(2) gluon propagator in Landau gauge is studied on the lattice. Our\ngauge fixing procedure employs simulated annealing and Z(2)-flips. It finds\nhigher maxima of the gauge functional compared with those obtained with the\nstandard overrelaxation and leads to systematic deviations of the gluon\npropagator in the infrared region. In particular, finite-size effects for\nlattice sizes from (1.7 fm)^4 up to (6.5 fm)^4 become weak. The propagator\nshows a plateau at p \\approx 300 MeV.",
        "positive": "Contribution to understanding the phase structure of strong interaction\n  matter: Lee-Yang edge singularities from lattice QCD: We present a calculation of the net baryon number density as a function of\nimaginary baryon number chemical potential, obtained with highly improved\nstaggered quarks (HISQ) at temporal lattice extent of $N_\\tau=4,6$. We\nconstruct various rational function approximations of the lattice data and\ndiscuss how poles in the complex plane can be determined from them. We compare\nour results of the singularities in the chemical potential plane to the\ntheoretically expected positions of the Lee-Yang edge singularity in the\nvicinity of the Roberge-Weiss and chiral phase transitions. We find a\ntemperature scaling that is in accordance with the expected power law behavior."
    },
    {
        "anchor": "Extraction of the isovector magnetic form factor of the nucleon at zero\n  momentum: The extraction of the magnetic form factor of the nucleon at zero momentum\ntransfer is usually performed by adopting a parametrization for its momentum\ndependence and fitting the results obtained at finite momenta. We present\nposition space methods that rely on taking the derivative of relevant\ncorrelators to extract directly the magnetic form factor at zero momentum\nwithout the need to assume a functional form for its momentum dependence. These\nmethods are explored on one ensemble using $N_f=2+1+1$ Wilson twisted mass\nfermions.",
        "positive": "QCD finite T transition -- Comparison between Wilson and staggered\n  results: A quantitative comparison between the finite temperature behaviour of the\nstaggered and Wilson fermion formulations are performed. The comparison is\nbased on a physical quantity that is expected to be quite sensitive to the\nfermionic features of the action. For that purpose we use the height of the\npeak for $d\\chi_s/dT$, where $\\chi_s$ is the quark number susceptibility."
    },
    {
        "anchor": "Baryon masses from full QCD+QED${}_\\text{C}$ simulations: In these proceedings we present preliminary results for the masses of the\nproton, neutron and $\\Omega^-$ baryons obtained from QCD+QED lattice\nsimulations performed with four dynamical quarks using C$^*$ boundary\nconditions. These results are part of the ongoing effort of the RC${}^*$\ncollaboration discussed in the companion proceedings, and have been obtained on\na single ensemble in which the renormalised electromagnetic coupling is\n$\\alpha_{\\text{em}}\\sim 0.04$, the physical volume is $L\\sim 1.7$ fm and the\nmasses of the four dynamical quarks have been tuned at the $U$--spin symmetric\npoint $m_d=m_s$. We demonstrate on this unphysical ensemble that baryon masses\ncan be calculated with satisfactory precision when including QED without the\nneed for gauge--fixing and perturbation theory. This makes us confident in the\neffectiveness of the strategy presented here also in the case of simulations\ncloser to the physical point.",
        "positive": "Nucleon-$J/\u03c8$ and nucleon-$\u03b7_{c}$ scattering in $P_{c}$ pentaquark\n  channels from LQCD: The lattice QCD simulation of $NJ/\\psi$ and $N\\eta_c$ scattering is performed\nat $m_\\pi\\simeq 266~$MeV in channels with all possible $J^P$. This includes\n$J^P=3/2^\\pm$ and $5/2^\\pm$ where LHCb discovered $P_c(4380)$ and $P_c(4450)$\npentaquark states in proton$-J/\\psi$ decay. This is the first lattice\nsimulation that reaches the energies 4.3-4.5 GeV where pentaquarks reside.\nSeveral decay channels are open in this energy region and we explore the fate\nof $P_c$ in the one-channel approximation in this work. Energies of eigenstates\nare extracted for the nucleon-charmonium system at zero total momentum for all\nquantum numbers, i.e. six lattice irreducible representations. No significant\nenergy shifts are observed. The number of the observed lattice eigenstates\nagrees with the number expected for non-interacting charmonium and nucleon.\nThus, we do not find any strong indication for a resonance or a bound state in\nthese exotic channels within one-channel approximation. This possibly indicates\nthat the coupling of $NJ/\\psi $ channel with other two-hadron channels might be\nresponsible for $P_c$ resonances in experiment. One of the challenges of this\nstudy is that up to six degenerate $J/\\psi(p) N(-p)$ eigenstates are expected\nin the non-interacting limit due non-zero spins of $J/\\psi$ and N, and we\nestablish all of them in the spectra."
    },
    {
        "anchor": "Gauge transformations in lattice chiral theories: We show that gauge-transformation properties of correlation functions in\nchiral gauge theories on the finite lattice are determined in a general way.",
        "positive": "Towards a precise determination of the equation of state of QCD at\n  high-temperature: We present preliminary results towards a fully non-perturbative determination\nof the equation of state of QCD at very high-temperatures, $T\\approx 3-80\\,{\\rm\nGeV}$. The key ingredient is the lattice formulation of QCD in a moving\nreference frame, which allows us for a neat determination of the entropy\ndensity from simple expectation values of the momentum-components of the\nenergy-momentum tensor. For the computation we employ $N_{\\rm f}=3$ flavours of\nnon-perturbatively O($a$)-improved Wilson-fermions. We present an analysis of\nthe O($a$)-improvement of the expectation values entering the determination,\nand show how these can be accurately computed in simulations."
    },
    {
        "anchor": "Tensor RG calculations and quantum simulations near criticality: We discuss the reformulation of the O(2) model with a chemical potential and\nthe Abelian Higgs model on a 1+1 dimensional space-time lattice using the\nTensor Renormalization Group (TRG) method. The TRG allows exact blocking and\nconnects smoothly the classical Lagrangian approach to the quantum Hamiltonian\napproach. We calculate the entanglement entropy in the superfluid phase of the\nO(2) model and show that it approximately obeys the logarithmic Calabrese-Cardy\nscaling obtained from Conformal Field Theory (CFT). We calculate the Polyakov\nloop in the Abelian Higgs model and discuss the possibility of a deconfinement\ntransition at finite volume. We propose Bose-Hubbard Hamiltonians implementable\non optical lattices as quantum simulators for CFT models.",
        "positive": "Nucleon structure with domain wall fermions: We report the status of RBCK calculations on nucleon structure with quenched\nand dynamical domain wall fermions. The quenched results for the moments of\nstructure functions (< x >_q), (< x>_{\\Delta u - \\Delta d}), and (< 1 >_{\\delta\nq}) from 1.3 GeV cutoff lattices are complete with non perturbative\nrenormalization (NPR). The dynamical results with two degenerate dynamical\nquark flavors from 1.7 GeV cutoff lattices are without NPR while the axial\ncharge result is naturally renormalized."
    },
    {
        "anchor": "Lattice Simulations and Effective Theories: I present a brief introduction to the lattice formulation of quantum field\ntheory, and discuss the use of lattice simulations for studies in particle\nphysics phenomenology. The computation of $f_B$, the decay constant of the\n$B$-meson, is used as a case study. I also explain the appearance and\ncancellation of ``renormalons'' in the evaluation of power corrections\n(higher-twist corrections) in hard scattering and decay processes.",
        "positive": "An update on the BQCD Hybrid Monte Carlo program: We present an update of BQCD, our Hybrid Monte Carlo program for simulating\nlattice QCD. BQCD is one of the main production codes of the QCDSF\ncollaboration and is used by CSSM and in some Japanese finite temperature and\nfinite density projects. Since the first publication of the code at Lattice\n2010 the program has been extended in various ways. New features of the code\ninclude: dynamical QED, action modification in order to compute matrix elements\nby using Feynman-Hellman theory, more trace measurements, a more flexible\nintegration scheme, polynomial filtering, term-splitting for RHMC, and a\nportable implementation of performance critical parts employing SIMD."
    },
    {
        "anchor": "Non-perturbative Renormalization for Improved Staggered Bilinears: We apply non-perturbative renormalization to bilinears composed of improved\nstaggered fermions. We explain how to generalize the method to staggered\nfermions in a way which is consistent with the lattice symmetries, and\nintroduce a new type of lattice bilinear which transforms covariantly and\navoids mixing. We derive the consequences of lattice symmetries for the\npropagator and vertices. We implement the method numerically for\nhypercubic-smeared (HYP) and asqtad valence fermion actions, using lattices\nwith asqtad sea quarks generated by the MILC collaboration. We compare the\nnon-perturbative results so obtained to those from perturbation theory, using\nboth scale-independent ratios of bilinears (of which we calculate 26), and the\nscale-dependent bilinears themselves. Overall, we find that one-loop\nperturbation theory provides a successful description of the results for\nHYP-fermions if we allow for a truncation error of roughly the size of the\nsquare of the one-loop term (for ratios) or of size O(1) \\times \\alpha^2 (for\nthe bilinears themselves). Perturbation theory is, however, less successful at\ndescribing the non-perturbative asqtad results.",
        "positive": "Non-perturbative running of quark masses in three-flavour QCD: We present our preliminary results for the computation of the\nnon-perturbative running of renormalized quark masses in $N_f = 3$ QCD, between\nthe electroweak and hadronic scales, using standard finite-size scaling\ntechniques. The computation is carried out to very high precision, using\nmassless $\\mathcal{O}(a)$-improved Wilson quarks. Following the strategy\nadopted by the ALPHA Collaboration for the running coupling, different schemes\nare used above and below a scale $\\mu_0 \\sim m_b$, which differ by using either\nthe Schr\\\"odinger Functional or Gradient Flow renormalized coupling. We discuss\nour results for the running in both regions, and the procedure to match the two\nschemes."
    },
    {
        "anchor": "Steiner Variations on Random Surfaces: Ambartzumian et.al. suggested that the modified Steiner action functional had\ndesirable properties for a random surface action. However, Durhuus and Jonsson\npointed out that such an action led to an ill-defined grand-canonical partition\nfunction and suggested that the addition of an area term might improve matters.\nIn this paper we investigate this and other related actions numerically for\ndynamically triangulated random surfaces and compare the results with the\ngaussian plus extrinsic curvature actions that have been used previously.",
        "positive": "A Prediction of the B*_c mass in full lattice QCD: By using the Highly Improved Staggered Quark formalism to handle charm,\nstrange and light valence quarks in full lattice QCD, and NRQCD to handle\nbottom valence quarks we are able to determine accurately ratios of the B meson\nvector-pseudoscalar mass splittings, in particular,\n(m(B*_c)-m(B_c))/(m(B*_s)-m(B_s)). We find this ratio to be 1.15(15), showing\nthe `light' quark mass dependence of this splitting to be very small. Hence we\npredict m(B_c*) = 6.330(7)(2)(6) GeV where the first two errors are from the\nlattice calculation and the third from existing experiment. This is the most\naccurate prediction of a gold-plated hadron mass from lattice QCD to date."
    },
    {
        "anchor": "Perturbative renormalization factors and O(a^2) corrections for lattice\n  4-fermion operators with improved fermion/gluon actions: In this work we calculate the corrections to the amputated Green's functions\nof 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel\naspects of our calculations is that they are carried out to O(a^2) (a: lattice\nspacing). We employ the Wilson/clover action for massless fermions (also\napplicable for the twisted mass action in the chiral limit) and a family of\nSymanzik improved actions for gluons. Our calculations have been carried out in\na general covariant gauge. Results have been obtained for several popular\nchoices of values for the Symanzik coefficients. While our Green's function\ncalculations regard any pointlike 4-fermion operators which do not mix with\nlower dimension ones, we pay particular attention to DF=2 operators, both\nParity Conserving and Parity Violating (F: flavour). We compute the\nperturbative renormalization constants for a complete basis of 4-fermion\noperators and we study their mixing pattern. For some of the actions considered\nhere, even O(a^0) results did not exist in the literature to date. The\ncorrection terms which we calculate are essential ingredients for minimizing\nthe lattice artifacts which are present in non-perturbative evaluations of\nrenormalization constants with the RI'-MOM method. Our perturbative results,\nfor the matrix elements of DF=2 operators and for the corresponding\nrenormalization matrices, depend on a large number of parameters: coupling\nconstant, number of colors, lattice spacing, external momentum, clover\nparameter, Symanzik coefficients, gauge parameter. To make these results most\neasily accessible, we have included them in the distribution package of this\npaper, as an ASCII file named: 4-fermi.m; the file is best perused as\nMathematica input. The main results of this work have been applied to improve\nnon-perturbative estimates of the B_K-parameter in N_F=2 twisted mass lattice\nQCD.",
        "positive": "In-medium heavy-quarkonium from lattice QCD spectral functions: We discuss recent progress in the study of in-medium heavy quarkonium using\nfirst-principles lattice QCD calculations and effective field theory. In\nparticular our focus lies on real-time information carried by QCD spectral\nfunctions and we report on a novel strategy for their extraction from\nEuclidean-time simulations. Combining an effective description for heavy quarks\nwith finite temperature lattice QCD we compute in-medium spectra providing\ninsight in heavy quarkonium melting in a static thermal medium. On the other\nhand we use spectral information to extract the complex in-medium potential\nwhich provides the basis for a dynamical description of quarkonium real-time\nevolution via the Schr\\\"odinger equation."
    },
    {
        "anchor": "Lattice HQET with exponentially improved statistical precision: We introduce an alternative discretization for static quarks on the lattice\nretaining the O(a) improvement properties of the Eichten-Hill action. In this\nformulation, statistical fluctuations are reduced by a factor which grows\nexponentially with Euclidean time, x_0. For the first time, B-meson correlation\nfunctions are computed with good statistical precision in the static\napproximation for x_0>1 fm. At lattice spacings a \\approx 0.1 fm, a \\approx\n0.08 fm and a \\approx 0.07 fm the B_s-meson decay constant is determined in\nstatic and quenched approximations. A correction due to the finite mass of the\nb-quark is estimated by combining these static results with a recent\ndetermination of F_Ds.",
        "positive": "Moments of parton distribution functions of any order from lattice QCD: We describe a procedure to determine moments of parton distribution functions\nof any order in lattice QCD. The procedure is based on the gradient flow for\nfermion and gauge fields. The flowed matrix elements of twist-2 operators\nrenormalize multiplicatively, and the matching with the physical matrix\nelements can be obtained using continuum symmetries and the irreducible\nrepresentations of Euclidean 4-dimensional rotations. We calculate the matching\ncoefficients at one-loop in perturbation theory for moments of any order in the\nflavor non-singlet case. We also give specific examples of operators that could\nbe used in lattice QCD computations. It turns out that it is possible to choose\noperators with identical Lorentz indices and still have a multiplicative\nmatching. One can thus use twist-2 operators exclusively with temporal indices,\nthus substantially improving the signal-to-noise ratio in the computation of\nthe hadronic matrix elements."
    },
    {
        "anchor": "Charmonium systems after the deconfinement transition: The behavior of charmonia after the deconfinement transition is investigated\non quenched lattices. Analysis of temporal correlators on fine lattices at\ntemperatures upto 3 T_c show that the J/psi and eta_c survive the deconfinement\ntransition with little significant changes, and survive as bound states at\nleast upto 2.25 T_c. The spatially excited chi_c states suffer serious system\nmodifications, maybe dissolution, already a little above T_c.",
        "positive": "Simulating Dense Matter: I review the Sign Problem hindering lattice QCD simulations of dense baryonic\nmatter, focussing where possible on its physical relevance. The possibility of\navoiding the Sign Problem via a duality transformation is also briefly\nconsidered. Finally, I review evidence for deconfinement at non-zero quark\ndensity in recent simulations of Two Color QCD."
    },
    {
        "anchor": "Comments on the temperature dependence of the gauge topology: Recent efforts in lattice evaluation of the topological susceptibility had\nshown that at high temperatures it is given by well-separated instantons (even\nin QCD with light fermions, where those are highly suppressed). Recent\ndevelopment of the semiclassical theory suggest that below $T_{max}\\sim\n2.5T_c$, where Polyakov line has values between one and zero, the topology\nensemble can be represented by a plasma of instanton constituents (called\ninstanton-dyons or instanton-monopoles). It has been shown that such ensemble\nundergoes deconfinement and chiral transitions, semi-qualitatively reproducing\nthe lattice results. There are ongoing efforts to locate them on the lattice,\nor use (flavor-dependent) periodicity phases of the deformed versions of QCD on\nthe lattice and semiclassically, in order to test this theory. We here propose\nanother possibly useful tool: the topological susceptibility of a sub-lattice.",
        "positive": "Analytic approach to confinement and monopoles in lattice SU(2): We extend the approach of Banks, Myerson, and Kogut for the calculation of\nthe Wilson loop in lattice U(1) to the non-abelian SU(2) group. The original\ndegrees of freedom of the theory are integrated out, new degrees of freedom are\nintroduced in several steps. The centre group $Z_2$ enters automatically\nthrough the appearance of a field strength tensor $f_{\\mu \\nu}$, which takes on\nthe values 0 or 1 only. It obeys a linear field equation with the loop current\nas source. This equation implies that $f_{\\mu \\nu}$ is non vanishing on a\ntwo-dimensional surface bounded by the loop, and possibly on closed surfaces.\nThe two-dimensional surfaces have a natural interpretation as strings moving in\neuclidean time. In four dimensions we recover the dual Abrikosov string of a\ntype II superconductor, i.e. an electric string encircled by a magnetic\ncurrent. In contrast to other types of monopoles found in the literature, the\nmonopoles and the associated magnetic currents are present in every\nconfiguration. With some plausible, though not generally conclusive, arguments\nwe are directly led to the area law for large loops."
    },
    {
        "anchor": "Progress in Multibaryon Spectroscopy: Anchoring the nuclear interaction in QCD is a long-outstanding problem in\nnuclear physics. While the lattice community has made enormous progress in\nmesonic physics and single nucleon physics, continuum-limit physical-point\nmulti-nucleon physics has remained out of reach. I will review CalLat's\nstrategy for multi-nucleon spectroscopy and our latest results.",
        "positive": "Critical exponents from large mass expansion: We perform estimation of critical exponents via large mass expansion under\ncrucial help of delta-expansion. We address to the three dimensional Ising\nmodel at high temperature and estimate omega, the correction-to-scaling\nexponent, nu, eta and gamma in unbiased and self-contained manner. The results\nread at the highest 25th order expansion omega=0.8002, nu=0.6295, eta=0.0369\nand gamma=1.2357. Estimation biased by omega=0.84(4) is also performed and\nproved to be in agreement with the summary of recent literatures."
    },
    {
        "anchor": "Euclidean relativistic quantum mechanics - scattering asymptotic\n  conditions: We discuss the formulation of the scattering asymptotic condition in a\nrelativistic quantum theory formulated in terms of reflection positive\nEuclidean Green functions.",
        "positive": "Regge's space-time skeletons and the quantization of 2d gravity: Regge's method for regularizing euclidean quantum gravity is applied to two\ndimensional gravity. Using topologies with genus zero and two and a scale\ninvariant measure, we show that the Regge method fails to reproduce the values\nof the string susceptibilities of the continuum model."
    },
    {
        "anchor": "Super-heavy Quarkonia and the Gluon Condensate: The early idea that a non-perturbative gluon condensate affects the spectrum\nof heavy quarks is revisited in the light of modern simulation techniques. We\nevaluate the low lying spectrum of bound states of two heavy quarks for large\nhypothetical quark mass, m_Q > m_b, using non-relativistic QCD and compare with\nother models to test the consistency.",
        "positive": "Multi-level computation of the hadronic vacuum polarization contribution\n  to $(g_\u03bc-2)$: The first results from the Fermilab E989 experiment have confirmed the\nlong-standing tension between the experimental determination of the muon\nanomalous magnetic moment $a_\\mu=(g_\\mu-2)/2$ and its SM determination using\nthe dispersive approach. In order to match the expected final precision from\nE989, the current uncertainty on ab initio determinations using lattice QCD\nmust be decreased by a factor 5-15, a goal which is hampered by the\nsignal-to-noise ratio problem of the electromagnetic current correlator.\nMulti-level Monte Carlo integration with fermions is a method which reduces the\nvariance of correlators exponentially in the distance of the fields. Here we\ndemonstrate that the variance reduction in a realistic two-level simulation\nwith a pion mass of 270 MeV, linear size of 3 fm and lattice spacing around\n0.065 fm is sufficient to compute the tail of the current correlator with the\nstatistical accuracy required for the hadronic vacuum polarization contribution\nto $a_\\mu$. An efficient estimator is also employed for computing the\ndisconnected contribution."
    },
    {
        "anchor": "Stochastic Lattice Gas Model for a Predator-Prey System: We propose a stochastic lattice gas model to describe the dynamics of two\nanimal species population, one being a predator and the other a prey. This\nmodel comprehends the mechanisms of the Lotka-Volterra model. Our analysis was\nperformed by using a dynamical mean-field approximation and computer\nsimulations. Our results show that the system exhibits an oscillatory behavior\nof the population densities of prey and predators. For the sets of parameters\nused in our computer simulations, these oscillations occur at a local level.\nMean-field results predict synchronized collective oscillations.",
        "positive": "Order parameters and boundary effects in U(1) lattice gauge theory: We show that, independently of the boundary conditions, the two phases of the\n4-dimensional compact U(1) lattice gauge theory can be characterized by the\npresence or absence of an ``infinite'' current network, with an appropriate\ndefinition of ``infinite'' for the various types of boundary conditions imposed\non the finite lattice. The probability for the occurrence of an ``infinite''\nnetwork takes values 0 or 1 in the cold and hot phase, respectively. It thus\nconstitutes a very efficient order parameter, which allows one to determine the\ntransition region at low computational cost. In addition, for open and fixed\nboundary conditions we address the question of the impact of inhomogeneities\nand give examples of the reappearance of an energy gap already at moderate\nlattice sizes."
    },
    {
        "anchor": "Scaling topological charge in the CP^3 model using a fixed point action: We define a fixed point action in two-dimensional lattice CP^{N-1} models.\nThe fixed point action is a classical perfect lattice action, which is expected\nto show strongly reduced cut-off effects in numerical simulations. Furthermore,\nthe action has scale invariant instanton solutions, which enables us to define\na topological charge without topological defects. We present results for the\nscaling of the topological suceptibility from a Monte Carlo simulation in the\nCP^3 model.",
        "positive": "The curvature of the chiral phase transition line for small values of\n  $\u03bc_B$: We present preliminary results from an ongoing calculation to determine the\ncurvature of the chiral phase transition line in the chiral limit along the\nlight-light, light-strange and strange-strange chemical potential directions.\nWe do this by studying the appropriate $\\mu$-derivatives of the chiral\ncondensate as a function of the quark mass and comparing them to the scaling\npredictions of $3d$-$O(N)$ theory. We work at a fixed lattice spacing,\n$N_\\tau=6$ and at four different quark masses $m_\\pi\\approx$ 140, 110, 90 and\n80 MeV. For the light quark curvature, we obtain a value\n0.03$\\leqslant\\kappa_{ll}\\leqslant$0.11. We also find that both strange and\nlight-strange curvatures are around an order of magnitude smaller. Currently,\nthe light-strange curvature is the least constrained curvature and could have\neither sign, though our results seem to prefer a slightly negative value."
    },
    {
        "anchor": "Renormalized quark-anti-quark free energy: We present results on the renormalized quark-anti-quark free energy in SU(3)\ngauge theory at finite temperatures. We discuss results for the singlet, octet\nand colour averaged free energies and comment on thermal relations which allow\nto extract separately the potential energy and entropy from the free energy.",
        "positive": "Strong-isospin-breaking correction to the muon anomalous magnetic moment\n  from lattice QCD at the physical point: All lattice-QCD calculations of the hadronic-vacuum-polarization contribution\nto the muon's anomalous magnetic moment to-date have been performed with\ndegenerate up- and down-quark masses. Here we calculate directly the\nstrong-isospin-breaking correction to $a_\\mu^{\\rm HVP}$ for the first time with\nphysical values of $m_u$ and $m_d$ and dynamical $u$, $d$, $s$, and $c$ quarks,\nthereby removing this important source of systematic uncertainty. We obtain a\nrelative shift to be applied to lattice-QCD results obtained with degenerate\nlight-quark masses of $\\delta a_\\mu^{{\\rm HVP,} m_u \\neq m_d}$= +1.5(7)%, in\nagreement with estimates from phenomenology and a recent lattice-QCD\ncalculation with unphysically heavy pions."
    },
    {
        "anchor": "First experience with classical-statistical real-time simulations of\n  anomalous transport with overlap fermions: We present first results of classical-statistical real-time simulations of\nanomalous transport phenomena with overlap fermions. We find that even on small\nlattices overlap fermions reproduce the real-time anomaly equation with much\nbetter precision than Wilson-Dirac fermions on an order of magnitude larger\nlattices. The difference becomes much more pronounced for quickly changing\nelectromagnetic fields, especially if one takes into account the back-reaction\nof fermions on electromagnetism. As test cases, we consider chirality pumping\nin parallel electric and magnetic fields and mixing between the plasmon and the\nChiral Magnetic Wave.",
        "positive": "Logarithmic Corrections to the Equation of State in the SU(2)xSU(2)\n  Nambu - Jona-Lasinio Model: We present results from a Monte Carlo simulation of the Nambu - Jona-Lasinio\nmodel, with continuous SU(2)xSU(2) chiral symmetry, in four Euclidean\ndimensions. Different model equations of state, corresponding to different\ntheoretical scenarios, are tested against the order parameter data. The results\nare sensitive to necessary assumptions about the shape and extent of the\nscaling region. Our best fits favour a trivial scenario in which the\nlogarithmic corrections are qualitatively similar to those predicted by the\nlarge N_f approximation. This is supported by a separate analysis of finite\nvolume corrections for data taken directly in the chiral limit."
    },
    {
        "anchor": "Composite reweighting with Imaginary Chemical Potentials in SU(3): We review the overlap pathology of the Glasgow reweighting method for finite\ndensity QCD, and discuss the sampling bias that effects the determination of\nthe ensemble-averaged fugacity polynomial expansion coefficients that form the\nGrand Canonical Partition function. The expectation of the difference in free\nenergies between canonical partition functions generated with different\nmeasures is presented as an indicator of a systematic quark number dependent\nbiasing in the reweighting approach. The advantages of building up an unbiased\npolynomial expansion for the Grand Canonical Partition function through a\nseries of parallel ensembles generated by reweighting with imaginary chemical\npotentials are then contrasted with addressing the overlap pathology through a\nsecondary reweighting.",
        "positive": "Study of the pion-pion scatterings with a combination of all-to-all\n  propagators and the HAL QCD method: In this paper, we report recent developments of the HAL QCD method for two\nhadron systems which contain quark annihilation processes using all-to-all\nquark propagators. We employ the hybrid method for all-to-all propagators,\nwhich combines a low-mode spectral decomposition of the quark propagator and\nstochastic estimators for remaining high modes, to evaluate the HAL QCD\npotentials for the first time. Using this method, we investigate the $I= 1,2$\n$\\pi \\pi$ scatterings at $m_{\\pi} \\approx 870$ MeV. In the $I=2$ study, we\nstudy how statistical fluctuations of the HAL QCD potentials are increased due\nto stochastic estimators in the hybrid method, compared with the conventional\none without them. We find that we can reduce statistical fluctuations by\ndilutions of stochastic noises in order to obtain sufficiently precise results,\nwhich turn out to be consistent with conventional results without all-to-all\npropagators. In the $I=1$ $\\pi \\pi$ case, which contains quark annihilation\nprocesses, we find that statistical fluctuations are further enhanced due to\nnoise contaminations in annihilation processes. We, however, confirm that we\ncan also reduce such statistical fluctuations to obtain the potential with a\nreasonable precision as long as we further increase a degree of dilutions at a\nprice of large numerical costs and take an appropriate scheme for the\npotential."
    },
    {
        "anchor": "Vector-Vector Scattering on the Lattice: In this work we present an extension of the L\\\"uscher formalism to include\nthe interaction of particles with spin, focusing on the scattering of two\nvector particles. The derived formalism will be applied to Scalar QED in the\nHiggs Phase, where the U(1) gauge boson acquires mass.",
        "positive": "Mixed adjoint-fundamental matter and applications towards SQCD and\n  beyond: Gauge theories with fermions in adjoint and fundamental representations are\nrelevant for many different applications including composite Higgs models and\ngeneral aspects of the confinement problem. We present first results from\nsimulations of SU(2) gauge theory with two Dirac fermions in the fundamental\nrepresentation and one adjoint flavor. In this context, we also discuss\napplications towards simulations of supersymmetric QCD."
    },
    {
        "anchor": "Computation of the one-loop Symanzik coefficients for the square action: We compute the one-loop coefficients for an alternative Symanzik improved\npure gauge SU{N} lattice action (N=2 and N=3). For the standard Symanzik\nimproved action we confirm previous results by L\\\"{u}scher and Weisz.",
        "positive": "Isolating the confining color field in the SU(3) flux tube: Using lattice Monte Carlo simulations of SU(3) pure gauge theory, we\ndetermine the spatial distribution of all components of the color fields\ncreated by a static quark and antiquark. We identify the components of the\nmeasured chromoelectric field transverse to the line connecting the\nquark-antiquark pair with the transverse components of an effective\nCoulomb-like field $\\vec{E}^C $ associated with the quark sources. Subtracting\n$\\vec{E}^C$ from the total simulated chromoelectric field $\\vec{E}$ yields a\nnon-perturbative, primarily longitudinal chromoelectric field $\\vec{E}^{NP}$,\nwhich we identify as the confining field. This is the first time that the\nchromoelectric field has been separated into perturbative and nonperturbative\ncomponents, creating a new tool to study the color field distribution between a\nquark and an antiquark, and thus the long distance force between them."
    },
    {
        "anchor": "Multi-Layer Structure in the Strongly Five Dimensional Abelian Higgs\n  Model: We explore the phase diagram of the 5--D anisotropic Abelian Higgs model by\nMonte Carlo simulations. In particular, we study the transition between the\nconfining phase and the four dimensional layered Higgs phase. We find that, in\na certain region of the lattice parameter space, this transition can be first\norder and that each layer moves into the Higgs phase independently of the\nothers (decoupling of layers).",
        "positive": "Scattering phases on finite lattices in the broken phase of the\n  four-dimensional O(4)-\u03c6^4 theory: According to a proposal of Luescher it is possible to determine elastic\nscattering phases in infinite volume from the energy spectrum of two-particle\nstates in a periodic box. We demonstrate the applicability of this method in\nthe broken phase of the four-dimensional O(4) non-linear sigma-model in a Monte\nCarlo study on finite lattices. This non-perturbative approach also permits the\nstudy of unstable particles, the sigma-particle in our case. We observe the\nsigma-resonance and extract its mass and width. In all scattering channels\ninvestigated the results are completely consistent with perturbative\ncalculations."
    },
    {
        "anchor": "Quark Mass dependence at Two Loops for Meson Properties: This talks contains a short introduction to Chiral Perturbation Theory and\nthe existing calculations to two-loop order in the mesonic sector. I include a\ndiscussion on which quantities the expansion can be organized in. The present\nbest values of the Low-Energy-Constants as determined from continuum physics\nare given as well as the assumptions underlying the fits to experimental data.\nI present plots of masses, decay constants and $f_+(0)$ in $K_{\\ell3}$ as a\nfunction of quark or meson masses. The talk ends with a list of things for\nwhich it would be extremely useful to have good results from lattice QCD\ncalculations.",
        "positive": "Low-lying positive-parity excited states of the nucleon: We present an overview of the correlation-matrix methods developed recently\nby the CSSM Lattice Collaboration for the isolation of excited states of the\nnucleon. Of particular interest is the first positive-parity excited-state of\nthe nucleon known as the Roper resonance. Using eigenvectors of the correlation\nmatrix we construct parity and eigenstate projected correlation functions which\nare analysed using standardized methods. The robust nature of this approach for\nextracting the eigenstate energies is presented. We report the importance of\nusing a variety of source and sink smearings in achieving this. Ultimately the\nindependence of the eigenstate energies from the interpolator basis is\ndemonstrated. In particular we consider $4\\times 4$ correlation matrices built\nfrom a variety of interpolators and smearing levels. Using FLIC fermions to\naccess the light quark mass regime, we explore the curvature encountered in the\nenergy of the states as the chiral limit is approached. We report a low-lying\nRoper state contrasting earlier results using correlation matrices. To the best\nof our knowledge, this is the first time a low-lying Roper resonance has been\nfound using correlation matrix methods. Finally, we present our results in the\ncontext of the Roper results reported by other groups."
    },
    {
        "anchor": "Lattice calculation of hadronic tensor of the nucleon: We report an attempt to calculate the deep inelastic scattering structure\nfunctions from the hadronic tensor calculated on the lattice. We used the\nBackus-Gilbert reconstruction method to address the inverse Laplace\ntransformation for the analytic continuation from the Euclidean to the\nMinkowski space.",
        "positive": "Renormalization and O(a)-improvement of the static-light axial current: A systematic treatment of O(a)-improvement in lattice theories with static\nquarks is presented. The Schr\\\"odinger functional is discussed and a\nrenormalization condition for the static axial current in the SF-scheme is\nintroduced. Its relation to other schemes is computed to 1-loop order and the\n2-loop anomalous dimension is derived. In finite volume renormalization schemes\nsuch as the SF-scheme, the renormalization scale dependence of the renormalized\nquantities is described by the step scaling function which can be computed by\nMC- simulations. We evaluate its lattice spacing effects in perturbation\ntheory."
    },
    {
        "anchor": "Lattice Quantum Chromodynamics: This lecture provides an introduction to quantum chromodynamics (QCD) on the\nlattice. The continuum limit and Monte Carlo simulations are briefly discussed.\nDifferent facets of QCD are nicely exhibited by the potential of a static quark\nand anti-quark pair and results from lattice calculations of this quantity will\nbe presented.",
        "positive": "Determination of the endpoint of the first order deconfiniement phase\n  transition in the heavy quark region of QCD: We study the endpoint of the first order deconfinement phase transition of 2\nand 2+1 flavor QCD in the heavy quark region. We perform simulations of\nquenched QCD and apply the reweighting method to study the heavy quark region.\nThe quark determinant for the reweighting is evaluated by a hopping parameter\nexpansion. To reduce the overlap problem, we introduce an external source term\nof the Polyakov loop in the simulation. We study the location of critical point\nat which the first order phase transition changes to crossover by investigating\nthe histogram of the Polyakov loop and applying the finite-size scaling\nanalysis. We estimate the truncation error of the hopping parameter expansion,\nand discuss the lattice spacing dependence and the spatial volume dependence in\nthe result of the critical point."
    },
    {
        "anchor": "Exotic meson spectroscopy from the clover action at beta = 5.85 and 6.15: We repeat our original simulations of the hybrid meson spectrum using the\nclover action, as a check on lattice artifacts. Our results for the 1-+ masses\ndo not substantially change. We present preliminary results for the wave\nfunction of the 1-+ state in Coulomb gauge.",
        "positive": "The Glueball content of $\u03b7_c$: We carry out the first lattice QCD derivation of the mixing energy and the\nmixing angle of the pseudoscalar charmonium and glueball on two gauge ensembles\nwith $N_f=2$ degenerate dynamical charm quarks. The mixing energy is determined\nto be $49(6)$ MeV on the near physical charm ensemble, which seems insensitive\nto charm quark mass. By the assumption that $X(2370)$ is predominantly a\npseudoscalar glueball, the mixing angle is determined to be approximately\n$4.6(6)^\\circ$, which results in a $+3.9(9)$ MeV mass shift of the ground state\npseudoscalar charmonium. In the mean time, the mixing can raise the total width\nof the pseudoscalar charmonium by 7.2(8) MeV, which explains to some extent the\nrelative large total width of the $\\eta_c$ meson. As a result, the branching\nfraction of $\\eta_c\\to \\gamma\\gamma$ can be understood in this\n$c\\bar{c}$-glueball mixing framework. On the other hand, the possible\ndiscrepancy of the theoretical predictions and the experimental results of the\npartial width of $J/\\psi\\to\\gamma\\eta_c$ cannot be alleviated by the\n$c\\bar{c}$-glueball mixing picture yet, which demands future precise\nexperimental measurements of this partial width."
    },
    {
        "anchor": "Two Colours QCD at Nonzero Chemical Potential: We identify the Goldstone modes appropriate to the low and high density\nphases of SU(2) lattice gauge theory with staggered fermions. We present hybrid\nMonte Carlo simulation results for susceptibilities on a 6^4 lattice at\nbeta=1.5, m=0.05. We specify how to implement a diquark source term in a\nlattice simulation and present first measurements of the lattice diquark\ncondensate as a function of the diquark source.",
        "positive": "Numerical simulation with light Wilson-quarks: The computational cost of numerical simulations of QCD with light dynamical\nWilson-quarks is estimated by determining the autocorrelation of various\nquantities. In test runs the expected qualitative behaviour of the pion mass\nand coupling at small quark masses is observed."
    },
    {
        "anchor": "A lattice non-perturbative definition of an SO(10) chiral gauge theory\n  and its induced standard model: The standard model is a chiral gauge theory where the gauge fields couple to\nthe right-hand and the left-hand fermions differently. The standard model is\ndefined perturbatively and describes all elementary particles (except\ngravitons) very well. However, for a long time, we do not know if we can have a\nnon-perturbative definition of standard model as a Hamiltonian quantum\nmechanical theory. In this paper, we propose a way to give a modified standard\nmodel (with 48 two-component Weyl fermions) a non-perturbative definition by\nembedding the modified standard model into a SO(10) chiral gauge theory and\nthen putting the SO(10) chiral gauge theory on a 3D spatial lattice with a\ncontinuous time. Such a non-perturbatively defined standard model is a\nHamiltonian quantum theory with a finite-dimensional Hilbert space for a finite\nspace volume. Using the defining connection between gauge anomalies and the\nsymmetry-protected topological orders, we show that any chiral gauge theory can\nbe non-perturbatively defined by putting it on a lattice in the same dimension,\nas long as the chiral gauge theory is free of all anomalies.",
        "positive": "Phase diagram of non-degenerate twisted mass fermions: We determine the phase diagram and pion spectrum for Wilson and twisted-mass\nfermions in the presence of non-degeneracy between the up and down quark and\ndiscretization errors, using Wilson and twisted-mass chiral perturbation\ntheory. We find that the CP-violating phase of the continuum theory (which\noccurs for sufficiently large non-degeneracy) is continuously connected to the\nAoki-phase of the lattice theory with degenerate quarks. We show that\ndiscretization effects can, in some cases, push simulations with physical\nmasses closer to either the CP-violating phase or another phase not present in\nthe continuum, so that at sufficiently large lattice spacings physical-point\nsimulations could lie in one of these phases."
    },
    {
        "anchor": "Comparing phenomenological estimates of dilepton decays of pseudoscalar\n  mesons with lattice QCD: Dilepton decays of pseudoscalar mesons have been drawing particular interest,\nthanks to their sensitivity to both the QCD dynamics at low energy and also\nsignals beyond the Standard Model. In this context, we shortly review our\nrecent study on an improved Standard-Model prediction for the rare decay\n$\\pi^0\\to e^+e^-$, and compare it with the first determination on the lattice\nthat predicted also the $\\pi^0\\to \\gamma\\gamma $ decay width as a byproduct. In\naddition, we discuss our recent work on $K_L\\to\\ell^+\\ell^-$ decays and its\nconnection to lattice QCD. We comment on the current uncertainty estimates and\ndiscuss how they could be improved profiting from future experiments and\nprogress in lattice QCD.",
        "positive": "Lattice QCD static potentials of the meson-meson and tetraquark systems\n  computed with both quenched and full QCD: We revisit the static potential for the $Q Q \\bar Q \\bar Q$ system using\nSU(3) lattice simulations, studying both the colour singlets groundstate and\nfirst excited state. We consider geometries where the two static quarks and the\ntwo anti-quarks are at the corners of rectangles of different sizes. We analyse\nthe transition between a tetraquark system and a two meson system with a two by\ntwo correlator matrix. We compare the potentials computed with quenched QCD and\nwith dynamical quarks. We also compare our simulations with the results of\nprevious studies and analyze quantitatively fits of our results with anzatse\ninspired in the string flip-flop model and in its possible colour excitations."
    },
    {
        "anchor": "Spontaneous chiral symmetry breaking and mass gap of QCD in finite\n  volume: We present the lattice QCD simulation with the 2+1+1 flavor full QCD\nensembles using near-physical quark masses and different spatial sizes $L$, at\n$a\\sim$ 0.055 fm. The results suggest that spontaneous chiral symmetry breaking\nis effectively restored at $L\\le 1.0$ fm, while the gap between the nucleon and\npion masses remains.",
        "positive": "Transfer Matrix for Partially Quenched QCD: We construct the transfer matrix for the ghost sector of partially quenched\nQCD. This transfer matrix is not hermitian, but we show that it is still\nbounded. We thus expect that all euclidean correlation functions will decay\nexponentially with distance (up to possible powers), and demonstrate that this\nis indeed the case for free ghost quarks."
    },
    {
        "anchor": "Non-perturbative renormalization of left-left four-fermion operators in\n  quenched lattice QCD: We define a family of Schroedinger Functional renormalization schemes for the\nfour-quark multiplicatively renormalizable operators of the $\\Delta F = 1$ and\n$\\Delta F = 2$ effective weak Hamiltonians. Using the lattice regularization\nwith quenched Wilson quarks, we compute non-perturbatively the renormalization\ngroup running of these operators in the continuum limit in a large range of\nrenormalization scales. Continuum limit extrapolations are well controlled\nthanks to the implementation of two fermionic actions (Wilson and Clover). The\nratio of the renormalization group invariant operator to its renormalized\ncounterpart at a low energy scale, as well as the renormalization constant at\nthis scale, is obtained for all schemes.",
        "positive": "The \u03c6_3^4 lattice field theory viewed from the high-temperature side: We analyze high-temperature series expansions of the two-point and four-point\ncorrelation-functions in the three-dimensional euclidean lattice scalar field\ntheory with quartic self-coupling, which have been recently extended through\ntwenty-fifth order for the simple-cubic and body-centered-cubic lattices. We\nconclude that the length of the present series is sufficient for a fairly\naccurate description of the critical behavior of the model and confirm the\nvalidity of universality, scaling and hyperscaling. In the case of the\nbody-centered-cubic lattice, we determine the value of the quartic\nself-coupling for which the leading corrections to scaling approximately vanish\nand correspondingly the universal critical parameters can be determined with\nhigh accuracy. In particular, for the susceptibility and the correlation-length\nexponents we find \\gamma=1.2373(2) and \\nu=0.6301(2). For the four-point\nrenormalized coupling we find g=23.56(3). In the case of the simple-cubic\nlattice our results are consistent with earlier estimates."
    },
    {
        "anchor": "Importance of closed quark loops for lattice QCD studies of tetraquarks: To investigate the light scalar tetraquark candidate $a_0(980)$ (quantum\nnumbers $J^P =0^+$), a correlation matrix including a variety of two- and\nfour-quark interpolating operators has to be computed. We discuss efficient\ntechniques to compute the elements of this correlation matrix, in particular\ndiagrams with closed quark loops. Furthermore, we present evidence that such\ndiagrams are not negligible given our precision, and their contribution is\nessential to obtain physically meaningful results. In particular, we find\nindications of the existence of an \"additional\" state around the two-particle\nthresholds of $K+ \\bar K$ and $\\eta +\\pi$, which could correspond to the\n$a_0(980)$ meson.",
        "positive": "Effective Field Theories and Lattice QCD for the X Y Z frontier: Exotic states have been predicted before and after the advent of QCD. In the\nlast decades they have been observed at accelerator experiments in the sector\nwith two heavy quarks, at or above the quarkonium strong decay threshold and\ncalled X Y Z states. These states offer a unique possibility for investigating\nthe dynamical properties of strongly correlated systems in QCD. I will show how\nan alliance of nonrelativistic effective field theories and lattice can allow\nus to address these states in QCD. In particular I will explain what are the\nopportunities and challenges of lattice QCD in this respect and which new tools\nshould be developed."
    },
    {
        "anchor": "Z2 monopoles in D=2+1 SU(2) lattice gauge theory: We calculate the Euclidean action of a pair of Z2 monopoles (instantons), as\na function of their spatial separation, in D=2+1 SU(2) lattice gauge theory. We\ndo so both above and below the deconfining transition at T=Tc. At high T, and\nat large separation, we find that the monopole `interaction' grows linearly\nwith distance: the flux between the monopoles forms a flux tube (exactly like a\nfinite portion of a Z2 domain wall) so that the monopoles are linearly\nconfined. At short distances the interaction is well described by a Coulomb\ninteraction with, at most, a very small screening mass, possibly equal to the\nDebye electric screening mass. At low T the interaction can be described by a\nsimple screened Coulomb (i.e. Yukawa) interaction with a screening mass that\ncan be interpreted as the mass of a `constituent gluon'. None of this is\nunexpected, but it helps to resolve some apparent controversies in the recent\nliterature.",
        "positive": "Lattice QCD with 8 and 12 degenerate quark flavors: We compare extensive simulations of QCD with 8 and 12 flavors of degenerate\nquarks, using the DBW2 gauge action, naive staggered fermions, and the rational\nhybrid Monte Carlo algorithm. A variety of values of the coupling constant,\nquark mass, and lattice size have been used. Our data suggests that, as the\nbare coupling is decreased, a rapid cross-over, which dramatically changes the\nlattice scale, exists with both 8 and 12 flavors. The scale change across this\ncross-over is much larger with 12 flavors than it is with 8 flavors. All of the\nobservables we have measured, in both the zero and finite temperature systems,\nare consistent with a chiral symmetry breaking phase for the zero temperature\ntheory on the weak coupling side of the rapid cross-over."
    },
    {
        "anchor": "The QCD phase diagram for small densities from imaginary chemical\n  potential: We present results on the QCD phase diagram for mu_B <= pi T. Our simulations\nare performed with an imaginary chemical potential mu_I for which the fermion\ndeterminant is positive. On an 8^3 x 4 lattice with 2 flavors of staggered\nquarks, we map out the phase diagram and identify the pseudo-critical\ntemperature T_c(mu_I). For mu_I/T <= pi/3, this is an analytic function, whose\nTaylor expansion is found to converge rapidly, with truncation errors far\nsmaller than statistical ones. The truncated series may then be continued to\nreal mu, yielding the corresponding phase diagram for mu_B <~ 500 MeV. This\napproach provides control over systematics and avoids reweighting. We compare\nit with other recent work.",
        "positive": "Chiral Symmetry Versus the Lattice: After mentioning some of the difficulties arising in lattice gauge theory\nfrom chiral symmetry, I discuss one of the recent attempts to resolve these\nissues using fermionic surface states in an extra space-time dimension. This\npicture can be understood in terms of end states on a simple ladder molecule."
    },
    {
        "anchor": "Decays of an exotic $1^{-+}$ hybrid meson resonance in QCD: We present the first determination of the hadronic decays of the lightest\nexotic $J^{PC}=1^{-+}$ resonance in lattice QCD. Working with SU(3) flavor\nsymmetry, where the up, down and strange quark masses approximately match the\nphysical strange-quark mass giving $m_\\pi \\sim 700$ MeV, we compute\nfinite-volume spectra on six lattice volumes which constrain a scattering\nsystem featuring eight coupled channels. Analytically continuing the scattering\namplitudes into the complex energy plane, we find a pole singularity\ncorresponding to a narrow resonance which shows relatively weak coupling to the\nopen pseudoscalar--pseudoscalar, vector--pseudoscalar and vector--vector decay\nchannels, but large couplings to at least one kinematically-closed\naxial-vector--pseudoscalar channel. Attempting a simple extrapolation of the\ncouplings to physical light-quark mass suggests a broad $\\pi_1$ resonance\ndecaying dominantly through the $b_1 \\pi$ mode with much smaller decays into\n$f_1 \\pi$, $\\rho \\pi$, $\\eta' \\pi$ and $\\eta \\pi$. A large total width is\npotentially in agreement with the experimental $\\pi_1(1564)$ candidate state,\nobserved in $\\eta \\pi$, $\\eta' \\pi$, which we suggest may be heavily suppressed\ndecay channels.",
        "positive": "Infrared Gluon and Ghost Propagators from Lattice QCD. Results from\n  large asymmetric lattices: We report on the infrared limit of the quenched lattice Landau gauge gluon\nand ghost propagators as well as the strong coupling constant computed from\nlarge asymmetric lattices. The infrared lattice propagators are compared with\nthe pure power law solutions from Dyson-Schwinger equations (DSE). For the\ngluon propagator, the lattice data is compatible with the DSE solution. The\npreferred measured gluon exponent being $\\sim 0.52$, favouring a null zero\nmomentum propagator. The lattice ghost propagator shows finite volume effects\nand, for the volumes considered, the propagator does not follow a pure power\nlaw. Furthermore, the strong coupling constant is computed and its infrared\nbehaviour investigated."
    },
    {
        "anchor": "Gluon helicity distribution in the nucleon from lattice QCD and machine\n  learning: We present the first lattice QCD determination of the light cone gluon\nhelicity correlation parton distribution function (PDF) with numerical evidence\ntoward disfavoring negative gluon polarization in the nucleon. We present a\nsolution for eliminating an inevitable contamination term that dominates the\nEuclidean correlations and makes determining gluon helicity PDF unfeasible. The\nproposed synergy between lattice QCD and artificial intelligence offers a\nsuperior platform to alleviate the defining challenge of extracting quark and\ngluon PDFs from the lattice data that are available in a limited domain due to\na finite range of accessible hadron momenta. We suggest a systematically\nimprovable method to extract PDFs from the lattice data, independent of\ninadequate parametrizations. The result of the gluon helicity will improve our\nunderstanding of the role of spin in the strong interaction and the nucleon\nspin structure.",
        "positive": "Topology in QCD: Topology on the lattice is reviewed. In quenched QCD topological\nsusceptibility chi is fully understood. The Witten-Veneziano mechanism for the\neta' mass is confirmed. The topological susceptibility drops to zero at the\ndeconfining phase transition. Preliminary results are also presented for chi\nand chi' in full QCD, and for the spin content of the proton. The only problem\nthere is the difficulty of the usual Hybrid Monte Carlo algorithm to bring\ntopology to equilibrium."
    },
    {
        "anchor": "Field strength correlators in QCD at zero and non-zero temperature: We study, by numerical simulations on a lattice, the behaviour of the\ngauge--invariant field strength correlators in QCD both at zero temperature,\ndown to a distance of 0.1 fm, and at finite temperature, across the\ndeconfinement phase transition.",
        "positive": "Monte Carlo simulations of phonon propagation in the Fermi-sea of Weyl\n  spinors and detection of hysteresis effects using Groupoids: We considered symplectic quaternions sitting on a $(2+1)D$ lattice in\nmomentum space which interact with nearest neighbor interactions. The action is\nexpressed by fixed point actions given by the superposition of blocks whose\nlength of the contour is 4, 6 or 8 lattice spacings.\n  The spinors are on a finite $2D$ plane expressed as $u_1 a e_1+ u_2 a e_2$ (A\ntype) and/or on two $2D$ planes separated by $\\pm a e_1\\wedge e_2$ (B type). In\nthe A type, link actions on counter-clockwise rotating loop and on clockwise\nrotating loop cancel, however in the B type, the direction of links between the\nlower $2D$ plane and the upper $2D$ plane induces differences in the action.\nThe time-reversal conserving and spin rotational symmetry breaking actions can\nbe measured. Result of Monte-Carlo simulations of $64\\times 64$, $128\\times\n128$ and $256\\times 256$ spatial lattices are presented."
    },
    {
        "anchor": "Lattice studies of hadron physics with disconnected quark loops: Disconnected diagrams give crucial contributions to the physics of flavor\nsinglet hadrons and to scalar form factors of non-singlet hadrons. Naive\nlattice calculation of the disconnected diagrams, however, requires a huge\nnumber of fermion matrix inversions and hence a prohibitively large\ncomputational cost. In this article, we present recent studies of the\nflavor-singelt meson spectrum and nucleon strange quark content using the\nall-to-all propagator to calculate the relevant disconnected diagrams.",
        "positive": "Two flavor QCD and Confinement: We argue that the order of the chiral transition for N_f=2 is a sensitive\nprobe of the QCD vacuum, in particular of the mechanism of color confinement. A\nstrategy is developed to investigate the order of the transition by use of\nfinite size scaling analysis. An in-depth numerical investigation is performed\nwith staggered fermions on lattices with N_t=4 and N_s=12,16,20,24,32 and quark\nmasses am_q ranging from 0.01335 to 0.307036. The specific heat and a number of\nsusceptibilities are measured and compared with the expectations of an O(4)\nsecond order and of a first order phase transition. A second order transition\nin the O(4) and O(2) universality classes are excluded. Substantial evidence\nemerges for a first order transition. A detailed comparison with previous works\nis performed."
    },
    {
        "anchor": "Jet transport coefficient $\\hat{q}$ in lattice QCD: We present the first calculation of the jet transport coefficient $\\hat{q}$\nin quenched and (2+1)-flavor QCD on a 4-D Euclidean lattice. The light-like\npropagation of an energetic parton is factorized from the mean square gain in\nmomentum transverse to the direction of propagation, which is expressed in\nterms of the thermal field-strength field-strength correlator. The\nleading-twist term in its operator product expansion is calculated on the\nlattice. Continuum extrapolated quenched results, and full QCD estimates based\non un-renormalized lattice data, over multiple lattice sizes, are compared with\n(non) perturbative calculations and phenomenological extractions of $\\hat{q}$.\nThe lattice data for $\\hat{q}$ show a temperature dependence similar to the\nentropy density. Within uncertainties, these are consistent with\nphenomenological extractions, contrary to calculations using perturbation\ntheory.",
        "positive": "B-physics from Nf=2 tmQCD: the Standard Model and beyond: We present a lattice QCD computation of the b-quark mass, the B and B_s decay\nconstants, the B-mixing bag parameters for the full four-fermion operator basis\nas well as determinations for \\xi and f_{Bq}\\sqrt{B_i^{(q)}} extrapolated to\nthe continuum limit and to the physical pion mass. We used N_f = 2 twisted mass\nWilson fermions at four values of the lattice spacing with pion masses ranging\nfrom 280 to 500 MeV. Extrapolation in the heavy quark mass from the charm to\nthe bottom quark region has been carried out on ratios of physical quantities\ncomputed at nearby quark masses, exploiting the fact that they have an exactly\nknown infinite mass limit. Our results are m_b(m_b,\n\\overline{\\rm{MS}})=4.29(12) GeV, f_{Bs}=228(8) MeV, f_{B}=189(8) MeV and\nf_{Bs}/f_B=1.206(24). Moreover with our results for the bag-parameters we find\n\\xi=1.225(31), B_1^{(s)}/B_1^{(d)}=1.01(2), f_{Bd}\\sqrt{\\hat{B}_{1}^{(d)}} =\n216(10) MeV and f_{Bs}\\sqrt{\\hat{B}_{1}^{(s)}} = 262(10) MeV. We also computed\nthe bag parameters for the complete basis of the four-fermion operators which\nare required in beyond the SM theories. By using these results for the bag\nparameters we are able to provide a refined Unitarity Triangle analysis in the\npresence of New Physics, improving the bounds coming from B_{(s)}-\\bar B_{(s)}\nmixing."
    },
    {
        "anchor": "Sphaleron rate from lattice QCD: We compute the sphaleron rate on the lattice from the inversion of the\nEuclidean time correlators of the topological charge density, performing also\ncontrolled continuum and zero-smoothing extrapolations. The correlator\ninversion is performed by means of a recently-proposed modification of the\nBackus-Gilbert method.",
        "positive": "Coupling to Multihadron States with Chiral Fermions: Chiral symmerty is presumed to be a crucial component in the strong\ninteraction and QCD, but its role in spectroscopy, especially for baryons, has\nnot been fully explored. Compounding this, chiral fermions are uncommon in\nlattice calculations due to their expensive nature. We calculate $\\eta\\pi$,\n$K\\pi$ and $N\\pi$ states with $q\\bar{q}$ and $qqq$ interpolation fields at\n$a=0.114\\,\\mathrm{fm}$ on a $48^3\\times 96$ mixed-action lattice at the\nphysical pion mass, with domain-wall sea quarks and overlap valence quarks. We\nstudy the spectral weights of these states as a function of the valence pion\nmass, which ranges from $m_{\\pi}=115-665\\,\\mathrm{MeV}$, to be compared with\nthe results from non-chiral clover valence quarks on the same domain-wall\nlattice in order to examine their non-chiral effects, which are expected to\ndecrease with the lattice spacing."
    },
    {
        "anchor": "Rough Interfaces Beyond the Gaussian Approximation: We compare predictions of the Capillary Wave Model with Monte Carlo results\nfor the energy gap and the interface energy of the 3D Ising model in the\nscaling region. Our study reveals that the finite size effects of these\nquantities are well described by the Capillary Wave Model, expanded to two-loop\norder (one order beyond the Gaussian approximation).",
        "positive": "A lattice study of 3D compact QED at finite temperature: We study the deconfinement phase transition and monopole properties in the\nfinite temperature 3D compact Abelian gauge model on the lattice. We predict\nthe critical coupling as function of the lattice size in a simplified model to\ndescribe monopole binding. We demonstrate numerically that the monopoles are\nsensitive to the transition. In the deconfinement phase the monopoles appear in\nthe form of a dilute gas of magnetic dipoles. In the confinement phase both\nmonopole density and string tension differ from semiclassical estimates if\nmonopole binding is neglected. However, the analysis of the monopole clusters\nshows that the relation between the string tension and the density of monopoles\nin charged clusters is in reasonable agreement with those predictions. We study\nthe cluster structure of the vacuum in both phases of the model."
    },
    {
        "anchor": "Spectrum of the U(1) staggered Dirac operator in four dimensions: We compare the low-lying spectrum of the staggered Dirac operator in the\nconfining phase of compact U(1) gauge theory on the lattice to predictions of\nchiral random matrix theory. The small eigenvalues contribute to the chiral\ncondensate similar as for the SU(2) and SU(3) gauge groups. Agreement with the\nchiral unitary ensemble is observed below the Thouless energy, which is\nextracted from the data and found to scale with the lattice size according to\ntheoretical predictions.",
        "positive": "Search for the pentaquark resonance signature in lattice QCD: Claims concerning the possible discovery of the \\Theta^+ pentaquark, with\nminimal quark content uudd\\bar{s}, have motivated our comprehensive study into\npossible pentaquark states using lattice QCD. We review various pentaquark\ninterpolating fields in the literature and create a new candidate ideal for\nlattice QCD simulations. Using these interpolating fields we attempt to isolate\na signal for a five-quark resonance. Calculations are performed using improved\nactions on a large 20^3 x 40 lattice in the quenched approximation. The\nstandard lattice resonance signal of increasing attraction between baryon\nconstituents for increasing quark mass is not observed for spin-1/2 pentaquark\nstates. We conclude that evidence supporting the existence of a spin-1/2\npentaquark resonance does not exist in quenched QCD."
    },
    {
        "anchor": "Embedding the N=2 Supersymmetric Yang-Mills Theory in the Adjoint\n  Higgs-Yukawa Model on the Lattice: The N=2 supersymmetric Yang-Mills theory is formulated on the lattice. The\nfeasibility of numerical simulations is discussed.",
        "positive": "Observation of deconfinement in a cold dense quark medium: In this paper we study the confinement/deconfinement transition in lattice\n$SU(2)$ QCD at finite quark density and zero temperature. The simulations are\nperformed on an $32^4$ lattice with rooted staggered fermions at a lattice\nspacing $a = 0.044 \\mathrm{~fm}$. This small lattice spacing allowed us to\nreach very large baryon density (up to quark chemical potential $\\mu_q > 2000\n\\mathrm{~MeV}$) avoiding strong lattice artifacts. In the region $\\mu_q\\sim\n1000 \\mathrm{~MeV}$ we observe for the first time the confinement/deconfinement\ntransition which manifests itself in rising of the Polyakov loop and vanishing\nof the string tension $\\sigma$. After the deconfinement is achieved at $\\mu_q >\n1000 \\mathrm{~MeV}$, we observe a monotonous decrease of the spatial string\ntension $\\sigma_s$ which ends up with $\\sigma_s$ vanishing at $\\mu_q > 2000\n\\mathrm{~MeV}$. From this observation we draw the conclusion that the\nconfinement/deconfinement transition at finite density and zero temperature is\nquite different from that at finite temperature and zero density. Our results\nindicate that in very dense matter the quark-gluon plasma is in essence a\nweakly interacting gas of quarks and gluons without a magnetic screening mass\nin the system, sharply different from a quark-gluon plasma at large\ntemperature."
    },
    {
        "anchor": "Chiral condensate in the Schwinger model with Matrix Product Operators: Tensor network (TN) methods, in particular the Matrix Product States (MPS)\nansatz, have proven to be a useful tool in analyzing the properties of lattice\ngauge theories. They allow for a very good precision, much better than standard\nMonte Carlo (MC) techniques for the models that have been studied so far, due\nto the possibility of reaching much smaller lattice spacings. The real reason\nfor the interest in the TN approach, however, is its ability, shown so far in\nseveral condensed matter models, to deal with theories which exhibit the\nnotorious sign problem in MC simulations. This makes it prospective for dealing\nwith the non-zero chemical potential in QCD and other lattice gauge theories,\nas well as with real-time simulations. In this paper, using matrix product\noperators, we extend our analysis of the Schwinger model at zero temperature to\nshow the feasibility of this approach also at finite temperature. This is an\nimportant step on the way to deal with the sign problem of QCD. We analyze in\ndetail the chiral symmetry breaking in the massless and massive cases and show\nthat the method works very well and gives good control over a broad range of\ntemperatures, essentially from zero to infinite temperature.",
        "positive": "The Area Law in Matrix Models for Large N QCD Strings: We study the question whether matrix models obtained in the zero volume limit\nof 4d Yang-Mills theories can describe large N QCD strings. The matrix model we\nuse is a variant of the Eguchi-Kawai model in terms of Hermitian matrices, but\nwithout any twists or quenching. This model was originally proposed as a toy\nmodel of the IIB matrix model. In contrast to common expectations, we do\nobserve the area law for Wilson loops in a significant range of scale of the\nloop area. Numerical simulations show that this range is stable as N increases\nup to 768, which strongly suggests that it persists in the large N limit. Hence\nthe equivalence to QCD strings may hold for length scales inside a finite\nregime."
    },
    {
        "anchor": "Pion masses in 2-flavor QCD with $\u03b7$ condensation: We investigate the 2-flavor QCD with non-degenerate quark masses at\nlow-energy, using the chiral perturbation theory including the $\\eta$ meson and\nanomaly effects. For the fixed $m_d\\not=0$, the neutral pion becomes massless\nat two values of $m_u$, between which a spontaneously CP broken phase appears\nwith the neutral pion condensation. We then show that the topological\nsusceptibility diverges at these two critical points. We also consider the case\nof $m_u=m_d$ but $\\theta=\\pi$, equivalently $m_u= - m_d$ with $\\theta = 0$ by\nthe chiral rotation and show that the CP symmetry is spontaneously broken by\nthe $\\eta$ condensation at small $m$. Around $m=0$, three pions become\nNambu-Goldstone modes, showing non-standard behavior that $m_\\pi^2 = O(m^2)$,\nwhich, however, is consistent with the chiral Ward-Takahashi identities.}",
        "positive": "Critical region of the random bond Ising model: We describe results of the cluster algorithm Special Purpose Processor\nsimulations of the 2D Ising model with impurity bonds. Use of large lattices,\nwith the number of spins up to $10^6$, permitted to define critical region of\ntemperatures, where both finite size corrections and corrections to scaling are\nsmall. High accuracy data unambiguously show increase of magnetization and\nmagnetic susceptibility effective exponents $\\beta$ and $\\gamma$, caused by\nimpurities. The $M$ and $\\chi$ singularities became more sharp, while the\nspecific heat singularity is smoothed. The specific heat is found to be in a\ngood agreement with Dotsenko-Dotsenko theoretical predictions in the whole\ncritical range of temperatures."
    },
    {
        "anchor": "The S Parameter in QCD from Domain Wall Fermions: We have computed the SU(2) Low Energy Constant l5 and the mass splitting\nbetween charged and neutral pions from a lattice QCD simulation of nf = 2 + 1\nflavors of Domain Wall Fermions at a scale of a-1 = 2.33GeV. Relating l5 to the\nS parameter in QCD we obtain a value of S(mH=120GeV) = 0.42(7), in agreement\nwith previous determinations. Our result can be compared with the value of S\nfrom electroweak precision data which constrains strongly interacting models of\nnew physics like Technicolor. This work in QCD serves as a test for the methods\nto compute the S parameter with Domain Wall Fermions in theories beyond the\nStandard Model. We also infer a value for the pion mass splitting in agreement\nwith experiment.",
        "positive": "SU(2) Running Coupling Constant and Confinement in Minimal Coulomb and\n  Landau Gauges: We present a numerical study of the space-space and time-time components of\nthe gluon propagator at equal time in the minimal Coulomb gauge, and of the\ngluon and ghost propagators in the minimal Landau gauge. This work allows a\nnon-perturbative evaluation of the running coupling constant and a numerical\ncheck of Gribov's confinement scenarios for these two gauges. Our simulations\nare done in pure SU(2) lattice gauge theory at $\\beta = 2.2$. We consider\nseveral lattice volumes in order to control finite-volume effects and\nextrapolate our results to infinite lattice volume."
    },
    {
        "anchor": "A realistic interpretation of lattice gauge theories: Following recent assumptions to unify quantum mechanics and general\nrelativity, the structure of spacetime is suppose to be a consequence of the\nrelations among some fundamental objects, and its concept can be formulated\nwithout the reference to the intuition. As physical consequences the continuous\nlaws should be translated in to difference equations and the lattice field\ntheories should be interpreted as a realistic model.",
        "positive": "Bayesian Inference for Contemporary Lattice Quantum Field Theory: Bayesian inference provides a rigorous framework to encapsulate our knowledge\nand uncertainty regarding various physical quantities in a well-defined and\nself-contained manner. Utilising modern tools, such Bayesian models can be\nconstructed with a remarkable flexibility, leaving us totally free to carefully\nchoose which assumption should be strictly enforced and which should on the\ncontrary be relaxed. The practical evaluation of these assumptions, together\nwith the data-driven selection or averaging of models, also appears in a very\nnatural way. In this presentation, I discuss its application in the context of\nlattice QCD and its common statistical problems. As a concrete illustration, I\npresent a few parametric and non-parametric hierarchical models applied to\nactual correlator data, from single exponential fits to spectral functions."
    },
    {
        "anchor": "The Rho Resonance from $N_f=2+1+1$ Twisted Mass Lattice QCD: We present first results on the $\\rho$ resonance parameters obtained with\n$N_f=2+1+1$ Wilson twisted mass fermions at maximal twist. Using ensembles of\nthe ETM collaboration, we provide results for two values of the lattice spacing\nand a range of pion mass values.",
        "positive": "Light baryons below and above the deconfinement transition: medium\n  effects and parity doubling: We study what happens to the Nucleon, Delta and Omega baryons in the hadronic\ngas and the quark-gluon plasma, with particular interest in parity doubling and\nits emergence as the plasma is heated. This is done using simulations of\nlattice QCD, employing the FASTSUM anisotropic Nf=2+1 ensembles, with four\ntemperatures below and four above the deconfinement transition temperature.\nBelow Tc we find that the positive-parity groundstate masses are largely\ntemperature independent, whereas the negative-parity ones are reduced\nconsiderably as the temperature increases. This may be of interest for\nheavy-ion phenomenology. Close to the transition, the masses are nearly\ndegenerate, in line with the expectation from chiral symmetry restoration.\nAbove Tc we find a clear signal of parity doubling in all three channels, with\nthe effect of the heavier s quark visible."
    },
    {
        "anchor": "Complex heavy-quark potential and Debye mass in a gluonic medium from\n  lattice QCD: We improve and extend our study of the complex in-medium heavy quark\npotential and its Debye mass $m_D$ in a gluonic medium with a finer scan around\nthe deconfinement transition and newly generated ensembles closer to the\nthermodynamic limit. On the lattices with larger physical volume, Re[V] shows\nsigns of screening, i.e. a finite $m_D$, only in the deconfined phase,\nreminiscent of a genuine phase transition. Consistently Im[V] exhibits nonzero\nvalues also only above $T_C$. We compare the behavior of Re[V] with the color\nsinglet free-energies that have been used historically to extract the Debye\nmass. An effective coupling constant is computed to assess the residual\ninfluence of the confining part of the potential at $T>0$. Our previous finding\nof a gradual screening of Re[V] around $T_C$ on finer lattices is critically\nreassessed and interpreted to originate from finite volume artifacts that\naffect the deployed $\\beta=7$, $\\xi_b=3.5$ parameter set at $N_s=32$.",
        "positive": "Lattice Formulation of the Standard Model: Combining the Kaplan surface mode approach for chiral fermions with added\nterms motivated by Eichten and Preskill suggests the possibility for a lattice\nregularization of the standard model which is finite, exactly gauge invariant,\nand only has physically desired states in its low energy spectrum. The\nconjectured scheme manifestly requires anomaly cancelation and explicitly\ncontains baryon and lepton number violating terms."
    },
    {
        "anchor": "Three-Dimensional 3-State Potts Model Revisited With New Techniques: We report a fairly detailed finite-size scaling analysis of the first-order\nphase transition in the three-dimensional 3-state Potts model on cubic lattices\nwith emphasis on recently introduced quantities whose infinite-volume\nextrapolations are governed `only' by exponentially small terms. In these\nquantities no asymptotic power series in the inverse volume are involved which\ncomplicate the finite-size scaling behaviour of standard observables related to\nthe specific-heat maxima or Binder-parameter minima. Introduced initially for\nstrong first-order phase transitions in q-state Potts models with ``large\nenough'' q, the new techniques prove to be surprisingly accurate for a q value\nas small as 3. On the basis of the high-precision Monte Carlo data of Alves `et\nal.' [Phys. Rev. B43 (1991) 5846], this leads to a refined estimate of $\\beta_t\n= 0.550,565(10)$ for the infinite-volume transition point.",
        "positive": "Gauged Nambu-Jona Lasinio Studies of the Triviality of Quantum\n  Electrodynamics: By adding a small, irrelevant four fermi interaction to the action of\nnoncompact lattice Quantum Electrodynamics (QED), the theory can be simulated\nwith massless quarks in a vacuum free of lattice monopoles. The lattice theory\npossesses a second order chiral phase transition which we show is\nlogarithmically trivial, with the same systematics as the Nambu-Jona Lasinio\nmodel. The irrelevance of the four fermi coupling is established numerically.\nThe widths of the scaling windows are examined in both the coupling constant\nand bare fermion mass directions in parameter space. For vanishing fermion mass\nwe find a broad scaling window in coupling. By adding a small bare fermion mass\nto the action we find that the width of the scaling window in the fermion mass\ndirection is very narrow. Only when a subdominant scaling term is added to the\nleading term of the equation of state are adequate fits to the data possible.\nThe failure of past studies of lattice QED to produce equation of state fits\nwith adequate confidence levels to seriously address the question of triviality\nis explained. The vacuum state of the lattice model is probed for topological\nexcitations, such as lattice Monopoles and Dirac strings, and these objects are\nshown to be non-critical along the chiral transition line as long as the four\nfermi coupling is nonzero."
    },
    {
        "anchor": "The Roughening Transition of the 3D Ising Interface: A Monte Carlo Study: We study the roughening transition of an interface in an Ising system on a 3D\nsimple cubic lattice using a finite size scaling method. The particular method\nhas recently been proposed and successfully tested for various solid on solid\nmodels. The basic idea is the matching of the renormalization-group-flow of the\ninterface with that of the exactly solvable body centered cubic solid on solid\nmodel. We unambiguously confirm the Kosterlitz-Thouless nature of the\nroughening transition of the Ising interface. Our result for the inverse\ntransition temperature $K_R=0.40754(5)$ is almost by two orders of magnitude\nmore accurate than the estimate of Mon, Landau and Stauffer.",
        "positive": "The U(1)-Higgs Model: Critical Behaviour in the Confinig-Higgs region: We study numerically the critical properties of the U(1)-Higgs lattice model,\nwith fixed Higgs modulus, in the region of small gauge coupling where the Higgs\nand Confining phases merge. We find evidence of a first order transition line\nthat ends in a second order point. By means of a rotation in parameter space we\nintroduce thermodynamic magnitudes and critical exponents in close resemblance\nwith simple models that show analogous critical behaviour. The measured data\nallow us to fit the critical exponents finding values in agreement with the\nmean field prediction. The location of the critical point and the slope of the\nfirst order line are accurately given."
    },
    {
        "anchor": "Toward the Continuum Limit of $B_K$ with the Quenched Kogut-Susskind\n  Quark Action: We present new results of our ongoing project toward a precision\ndetermination of the kaon $B$ parameter with the Kogut-Susskind quark action in\nquenched QCD. New results taken at $\\beta$=6.4 and $\\beta=5.7$ suggest that an\napparently linear $a$ dependence of $B_K$ previously observed for\n$\\beta=5.85-6.2$ arises from a change of curvature from convex to concave as\nthe lattice spacing is reduced. Fitting data for $\\beta\\geq 5.93$ with an\n$O(a^2)$ form yields $B_K$(NDR,2 GeV)=0.587(7)(17) in the continuum limit. We\nalso describe a finite-size study of $B_K$ at $\\beta=$ 6.0 and 6.4, and a\nreanalysis of the theoretical argument for $O(a^2)$ behavior.",
        "positive": "The Index and Axial Anomaly of a lattice Dirac operator: A remarkable feature of a lattice Dirac operator is discussed. Unlike the\nDirac operator for massless fermions in the continuum, this Ginsparg-Wilson\nlattice Dirac operator does not possess topological zero modes for any\ntopologically-nontrivial background gauge fields, even though it is\nexponentially-local, doublers-free, and reproduces correct axial anomaly for\ntopologically-trivial gauge configurations."
    },
    {
        "anchor": "Dynamical Restoration of Z_N Symmetry in SU(N)+Higgs Theories: We study the Z_N symmetry in SU(N)+Higgs theories with the Higgs field in the\nfundamental representation. The distributions of the Polyakov loop show that\nthe Z_N symmetry is explicitly broken in the Higgs phase. On the other hand,\ninside the Higgs symmetric phase the Polyakov loop distributions and other\nphysical observables exhibit the Z_N symmetry. This effective restoration of\nthe Z_N symmetry changes the nature of the confinement-deconfinenement\ntransition. We argue that the Z_N symmetry will lead to time independent\ntopological defect solutions in the Higgs symmetric deconfined phase which will\nplay important role at high temperatures.",
        "positive": "Domain wall fermion and CP symmetry breaking: We examine the CP properties of chiral gauge theory defined by a formulation\nof the domain wall fermion, where the light field variables $q$ and $\\bar q$\ntogether with Pauli-Villars fields $Q$ and $\\bar Q$ are utilized. It is shown\nthat this domain wall representation in the infinite flavor limit $N=\\infty$ is\nvalid only in the topologically trivial sector, and that the conflict among\nlattice chiral symmetry, strict locality and CP symmetry still persists for\nfinite lattice spacing $a$. The CP transformation generally sends one\nrepresentation of lattice chiral gauge theory into another representation of\nlattice chiral gauge theory, resulting in the inevitable change of propagators.\nA modified form of lattice CP transformation motivated by the domain wall\nfermion, which keeps the chiral action in terms of the Ginsparg-Wilson fermion\ninvariant, is analyzed in detail; this provides an alternative way to\nunderstand the breaking of CP symmetry at least in the topologically trivial\nsector. We note that the conflict with CP symmetry could be regarded as a\ntopological obstruction. We also discuss the issues related to the definition\nof Majorana fermions in connection with the supersymmetric Wess-Zumino model on\nthe lattice."
    },
    {
        "anchor": "Simulation of a scalar field on a fuzzy sphere: The phi^4 real scalar field theory on a fuzzy sphere is studied numerically.\nWe refine the phase diagram for this model where three distinct phases are\nknown to exist: a uniformly ordered phase, a disordered phase, and a\nnon-uniform ordered phase where the spatial SO(3) symmetry of the round sphere\nis spontaneously broken and which has no classical equivalent. The three\ncoexistence lines between these phases, which meet at a triple point, are\ncarefully located with particular attention paid to the one between the two\nordered phases and the triple point itself. In the neighbourhood of the triple\npoint all phase boundaries are well approximated by straight lines which,\nsurprisingly, have the same scaling. We argue that unless an additional term is\nadded to enhance the effect of the kinetic term the infinite matrix limit of\nthis model will not correspond to a real scalar field on the commutative sphere\nor plane.",
        "positive": "QCD string from D0 branes: We report the results of a set of high precision simulations performed in the\n3d gauge Ising model. We evaluated the interquark potential and the first few\nenergy levels and compared them with the predictions obtained with the\neffective Nambu-Goto string and with the free bosonic string. The data are\nprecise enough to unambiguously distinguish between the free string predictions\nand those obtained using the N-G effective string. At large distances we find a\nremarkable agreement between Monte Carlo data and N-G predictions for the first\nexcited energy level, while the free string picture is definitely excluded. As\nthe interquark distance is decreased (and/or the finite temperature becomes\nhigher) the Monte Carlo results show larger and larger deviations both from the\nN-G and from the free string predictions. In order to better understand this\nbehaviour we re-derived the effective Nambu-Goto theory result for the Polyakov\nloop correlator using a covariant quantization. We chose as boundary conditions\nthose of an open string attached to two D0-branes at spatial distance $R$, in a\ntarget space with compact euclidean time. Obviously our treatment is fully\nconsistent only in $d=26$. The extension to generic $d$ requires taking into\naccount the Liouville mode of Polyakov's formulation. The analogy with the\nstandard light cone calculation suggests that the contribution due to the\nLiouville field can be neglected for large $R$. At shorter scales, the\nLiouville mode cannot be neglected and its contribution to the interquark\npotential might be the source of the discrepancies with respect to the\neffective N-G results that we observe in our Monte Carlo simulations."
    },
    {
        "anchor": "The running coupling from the QCD Schr\u00f6dinger functional -- a one-loop\n  analysis: Starting from the Schr\\\"odinger functional, we give a non-perturbative\ndefinition of the running coupling constant in QCD. The spatial boundary\nconditions for the quark fields are chosen such that the massless Dirac\noperator in the classical background field has a large smallest eigenvalue. At\none-loop order of perturbation theory, we determine the matching coefficient to\nthe $\\MSbar$-scheme and discuss the quark mass effects in the $\\beta$-function.\nTo this order, we also compute the Symanzik improvement coefficient necessary\nto remove the $\\Oa$ lattice artefacts originating from the boundaries. For\nreasonable lattice resolutions and the standard Wilson action, lattice\nartefacts are found to be only weakly dependent on the lattice spacing $a$,\nwhile they vanish quickly with the improved action of Sheikholeslami and\nWohlert.",
        "positive": "SYM Correlators and the Maldacena Conjecture: We report on progress in evaluating quantum filed theories with\nsupersymmetric discrete light-cone quantization (SDLCQ). We compare the method\nto lattice gauge theory and point out its relevance for lattice calculations.\nAs an exciting application we present a test of the Maldacena conjecture. We\ntest the conjecture by evaluating the correlator of the stress-energy tensor in\nthe strong coupling field theory and comparing to the string theory prediction\nof its behavior as a function of the distance. Our numerical results support\nthe Maldacena conjecture and are within 10-15% of the predicted results."
    },
    {
        "anchor": "Full QED+QCD Low-Energy Constants through Reweighting: The effect of sea quark electromagnetic charge on meson masses is\ninvestigated, and first results for full QED+QCD low-energy constants are\npresented. The electromagnetic charge for sea quarks is incorporated in\nquenched QED+full QCD lattice simulations by a reweighting method. The\nreweighting factor, which connects quenched and unquenched QED, is estimated\nusing a stochastic method on 2+1 flavor dynamical domain-wall quark ensembles.",
        "positive": "Anderson Metal-to-Critical Transition in QCD: A picture of thermal QCD phase change based on the analogy with\nmetal-to-insulator transition of Anderson type was proposed in the past. In\nthis picture, a low-$T$ thermal state is akin to a metal with deeply infrared\n(IR) Dirac modes abundant and extended, while a high-$T$ state is akin to an\ninsulator with IR modes depleted and localized below a mobility edge\n$\\lambda_{\\text A} > 0$. Here we argue that, while $\\lambda_{\\text A}$ exists\nin QCD, a high-$T$ state is not an insulator in such an analogy. Rather, it is\na critical state arising due to a new singular mobility edge at $\\lambda_{\\text\nIR}=0$. This new mobility edge appears upon the transition into the recently\nproposed IR phase. As a key part of such a metal-to-critical scenario, we\npresent evidence using pure-glue QCD that deeply infrared Dirac modes in the IR\nphase extend to arbitrarily long distances. This is consistent with our\nprevious suggestion that the IR phase supports scale invariance in the\ninfrared. We discuss the role of Anderson-like aspects in this thermal regime\nand emphasize that the combination of gauge field topology and disorder plays a\nkey role in shaping its IR physics. Our conclusions are conveyed by the\nstructure of Dirac spectral non-analyticities."
    },
    {
        "anchor": "K pi scattering in moving frames: We extend our study of the $K\\pi$ system to moving frames and present an\nexploratory extraction of the masses and widths for the $K^*$ resonances by\nsimulating $K\\pi$ scattering in p-wave with $I=1/2$ on the lattice. Using\n$K\\pi$ systems with non-vanishing total momenta allows the extraction of phase\nshifts at several values of $K\\pi$ relative momenta. A Breit-Wigner fit of the\nphase renders a $K^*(892)$ resonance mass and $K^*\\to K \\pi $ coupling\ncompatible with the experimental numbers. We also determine the $K^*(1410)$\nmass assuming the experimental $K^*(1410)$ width. We contrast the resonant\n$I=1/2$ channel with the repulsive non-resonant $I=3/2$ channel, where the\nphase is found to be negative and small, in agreement with experiment.",
        "positive": "Center vortices and the quark propagator in SU(2) gauge theory: We study the behavior of the AsqTad quark propagator in Landau gauge on\nquenched SU(2) gauge configurations under the removal of center vortices. In\ncontrast to recent results in SU(3), we clearly see the infrared enhancement of\nthe mass function disappear if center vortices are removed, a sign of the\nintimate relation between center vortices and chiral symmetry breaking in SU(2)\ngauge-field theory. These results provide a benchmark with which to interpret\nthe SU(3) results. In addition, we consider vortex-only configurations. On\nthose, the quark dressing function behaves roughly as on the full\nconfigurations, and the mass function picks up an almost linear momentum\ndependence."
    },
    {
        "anchor": "Phase structure and real-time dynamics of the massive Thirring model in\n  1+1 dimensions using the tensor-network method: We present concluding results from our study for zero-temperature phase\nstructure of the massive Thirring model in 1+1 dimensions with staggered\nregularisation. Employing the method of matrix product states, several\nquantities, including two types of correlators, are investigated, leading to\nnumerical evidence of a Berezinskii-Kosterlitz-Thouless phase transition.\nExploratory results for real-time dynamics pertaining to this transition,\nobtained using the approaches of variational uniform matrix product state and\ntime-dependent variational principle, are also discussed.",
        "positive": "On the spectrum of the Wilson-Dirac lattice operator in topologically\n  non-trivial background configurations: We study characteristic features of the eigenvalues of the Wilson-Dirac\noperator in topologically non-trivial gauge field configurations by examining\ncomplete spectra of the fermion matrix. In particular we discuss the role of\neigenvectors with real eigenvalues as the lattice equivalents of the continuum\nzero-modes. We demonstrate, that those properties of the spectrum which\ncorrespond to non-trivial topology are stable under adding fluctuations to the\ngauge fields. The behavior of the spectrum in a fully quantized theory is\ndiscussed using QED_2 as an example."
    },
    {
        "anchor": "1/M correction to quenched QCD with non-zero baryon density: We study the \\kappa^2 corrections to the quenched limit of \\mu>0 QCD. We use\nan improved reweighting procedure.",
        "positive": "Lattice QCD at non-vanishing density: phase diagram, equation of state: We propose a method to study lattice QCD at non-vanishing temperature (T) and\nchemical potential (\\mu). We use n_f=2+1 dynamical staggered quarks with\nsemi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on\nthe Re(\\mu)-T plane is located. We calculate the pressure (p), the energy\ndensity (\\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and\n\\mu."
    },
    {
        "anchor": "Tests of Improved Kogut-Susskind Fermion Actions: Improved Kogut-Susskind quark actions containing repeatedly smeared links are\nstudied to address the issue of flavor symmetry restoration. As a measure of\nthe flavor symmetry restoration the mass spectrum of all the pions is computed.\nWe present results for several variants of the \"fat\" actions that are suitable\nfor full QCD simulations.",
        "positive": "More On The SU(2) Deconfinement Transition In The Mixed Action: We examine certain issues related to the universality of the SU(2) lattice\ngauge theory at non-zero temperatures. Using Monte Carlo simulations and strong\ncoupling expansions, we study the behavior of the deconfinement transition in\nan extended coupling plane (beta, beta_A) around the tricritical point where\nthe deconfinement transition changes from second to first order. Our numerical\nresults on N_tau =2,4,6,8 lattices show that the tricritical point first moves\ndown towards the Wilson axis and and then moves slowly upwards, if at all, as\nthe lattice spacing is reduced. Lattices with very large N_tau seem to be\ntherefore necessary for the mixed action to exhibit the critical exponents of\nthe three dimensional Ising model for positive values of the adjoint coupling."
    },
    {
        "anchor": "Center vortices and colour confinement in lattice QCD: We review lattice evidence showing that center-vortex condensation is a\nserious candidate for the mechanism of colour confinement in quantum\nchromodynamics.",
        "positive": "The chiral transition in two-flavor QCD: QCD with N_f=2 is a specially interesting system to investigate the chiral\ntransition. The order of the transition has still not been established. We\nreport the results of an in-depth numerical investigation performed with\nstaggered fermions on lattices with L_t=4 and L_s=12,16,20,24,32 and quark\nmasses am_q ranging from 0.01335 to 0.307036. Using finite-size techniques we\ncompare the scaling behavior of a number of thermodynamical susceptibilities\nwith the expectations of O(4) and O(2) universality classes. Clear disagreement\nis observed. Indications of a first order transition are found."
    },
    {
        "anchor": "Manifestly Gauge Invariant Models of Chiral Lattice Fermions: A manifestly gauge invariant lattice action for nonanomalous chiral models is\nproposed which leads in the continuum limit to the theory free of doublers.",
        "positive": "Grand canonical ensemble, multi-particle wave functions, scattering\n  data, and lattice field theories: We show that information about scattering data of a quantum field theory can\nbe obtained from studying the system at finite density and low temperatures. In\nparticular we consider models formulated on the lattice which can be exactly\ndualized to theories of conserved charge fluxes on lattice links. Apart from\neliminating the complex action problem at nonzero chemical potential mu, these\ndualizations allow for a particle world line interpretation of the dual fluxes\nfrom which one can extract data about the 2-particle wave function. As an\nexample we perform dual Monte Carlo simulations of the 2-dimensional O(3) model\nat nonzero mu and finite volume, whose non-perturbative spectrum consists of a\nmassive triplet of particles. At nonzero mu particles are induced in the\nsystem, which at sufficiently low temperature give rise to sectors of fixed\nparticle number. We show that the scattering phase shifts can be obtained\neither from the critical chemical potential values separating the sectors or\ndirectly from the wave function in the 2-particle sector. We find that both\nmethods give excellent agreement with the exact result. We discuss the\napplicability and generality of the new approaches."
    },
    {
        "anchor": "Non-perturbative BRST invariance and what it might be good for: We construct a local, gauge-fixed, lattice Yang-Mills theory with an exact\nBRST invariance, and with the same perturbative expansion as the standard\nYang-Mills theory. The ghost sector, and some of its BRST transformation rules,\nare modified to get around Neuberger's theorem. A special term is introduced in\nthe action to regularize the Gribov horizons, and the limit where the regulator\nis removed is discussed. We conclude with a few comments on what might be the\nphysical significance of this theory. We speculate that there may exist new\nstrong-interaction phases apart from the anticipated confinement phase.",
        "positive": "The QCD phase diagram at finite density: We study the density of states method to explore the phase diagram of the\nchiral transition on the tempeature and quark chemical potential plane. Four\nquark flavours are used in the analysis. Though the method is quite expensive\nsmall lattices show an indication for a triple-point connecting three different\nphases on the phase diagram."
    },
    {
        "anchor": "Nucleon form factors and the pion-nucleon sigma term: This talk summarizes the progress made since Lattice 2021 in understanding\nand controlling the contributions of towers of multihadron excited states with\nmass gaps starting lower than of radial excitations, and in increasing our\nconfidence in the extraction of ground state nucleon matrix elements. The most\nclear evidence for multihadron excited state contributions (ESC) is in\naxial/pseudoscalar form factors that are required to satisfy the PCAC relation\nbetween them. The talk examines the broader question--which and how many of the\ntheoretically allowed positive parity states $N(\\textbf p)\\pi(-\\textbf p)$,\n$N(\\textbf 0)\\pi(\\textbf 0)\\pi(\\textbf 0)$, $N(\\textbf p)\\pi(\\textbf 0)$,\n$N(\\textbf 0)\\pi(\\textbf p),\\ \\ldots$ make significant contributions to a given\nnucleon matrix element? New data for the axial, electric and magnetic form\nfactors are presented. They continue to show trends observed in Ref[1]. The\nN${}^2$LO $\\chi$PT analysis of the ESC to the pion-nucleon sigma term,\n$\\sigma_{\\pi N}$, has been extended to include the $\\Delta$ as an explicit\ndegree of freedom [2]. The conclusion reached in Ref [3] that $N \\pi$ and $N\n\\pi \\pi$ states each contribute about 10 MeV to $\\sigma_{\\pi N}$, and the\nconsistency between the lattice result with $N \\pi$ state included and the\nphenomenological estimate is not changed by this improvement.",
        "positive": "Type of dual superconductivity for the $SU(2)$ Yang--Mills theory: We investigate the type of dual superconductivity responsible for quark\nconfinement. For this purpose, we solve the field equations of the $U(1)$\ngauge-scalar model to obtain the static vortex solution in the whole range\nwithout restricting to the long-distance region. Then we use the resulting\nmagnetic field of the vortex to fit the gauge-invariant chromoelectric field\nconnecting a pair of quark and antiquark which was measured by numerical\nsimulations for $SU(2)$ Yang--Mills theory on a lattice. This result improves\nthe accuracy of the fitted value for the Ginzburg--Landau parameter to\nreconfirm the type I dual superconductivity for quark confinement which was\nclaimed by preceding works based on a fitting using the Clem ansatz. Moreover,\nwe calculate the Maxwell stress tensor to obtain the distribution of the force\naround the flux tube. This result suggests that the attractive force acts among\nchromoelectric flux tubes, in agreement with the type I dual superconductivity."
    },
    {
        "anchor": "$Z_S/Z_P$ from three-flavour lattice QCD: We report on advances in the non-perturbative determination of the ratio\n$Z_S/Z_P$ of the pseudoscalar to the scalar renormalization constants in\nthree-flavour lattice QCD with Wilson-clover quarks and tree-level Symanzik\nimproved gluons. The computations are based on the Ward identity approach,\nusing Schr\\\"odinger functional boundary conditions. Our results for $Z_S/Z_P$\ncover a range of couplings along a line of constant physics with lattice\nspacings of about 0.09 fm and below, relevant for phenomenological applications\nsuch as the calculation of renormalized quark masses.",
        "positive": "Topological properties of full QCD at the phase transition: We investigate the topological properties of the QCD vacuum with 4 flavours\nof dynamical staggered fermions at finite temperature. To calculate the\ntopological susceptibility we use the field-theoretical method. As in the\nquenched case, a sharp drop is observed for the topological susceptibility\nacross the phase transition."
    },
    {
        "anchor": "Critical Behaviour in the Dense Planar NJL Model: We present results of a Monte Carlo simulation of a 2+1 dimensional Nambu -\nJona-Lasinio model including diquark source terms. A diquark condensate <qq> is\nmeasured as a function of source strength j. In the vacuum phase <qq> vanishes\nlinearly with j as expected, but simulations in a region with non-zero baryon\ndensity suggest a power-law scaling and hence a critical system for all mu >\nmu_c. There is no diquark condensation signalling superfluidity. Comparisons\nare drawn with known results in two dimensional theories, and with the\npseudogap phase in cuprate superconductors. We also measure the dispersion\nrelation E(k) for fermionic excitations, and find results consistent with a\nsharp Fermi surface. Any superfluid gap Delta is constrained to be much less\nthan the constituent quark mass scale Sigma_0.",
        "positive": "Nucleon structure from lattice QCD - recent achievements and\n  perspectives: We present recent developments in lattice QCD simulations as applied in the\nstudy of hadron structure. We discuss the challenges and perspectives in the\nevaluation of benchmark quantities such as the nucleon axial charge and the\nisovector parton momentum fraction, as well as, in the computation of the\nnucleon $\\sigma$-terms, which involve the calculation of disconnected quark\nloop contributions."
    },
    {
        "anchor": "Compact QED: the photon propagator, confinement and positivity violation\n  for the pure gauge theory: The lattice Landau gauge photon propagator for the pure gauge theory is\nrevisited using large lattices. For the confined case we show that it has an\nassociated linearly growing potential, it has a mass gap, that is related to\nthe presence of monopoles, and its spectral function violates positivity. In\nthe deconfined phase, our simulations suggest that a free field theory is\nrecovered in the thermodynamic limit.",
        "positive": "Supersymmetry on the lattice: Lattice results in supersymmetry are summarized. Past, present and future\nperspectives are discussed."
    },
    {
        "anchor": "Colored-hadron distribution in hadron scattering in SU(2) lattice QCD: In color SU(2) lattice QCD, we investigate colored-diquark distributions in\ntwo-hadron scatterings by means of Bethe-Salpeter amplitudes on the lattice.\nWith colored-diquark operators in the Coulomb gauge, we measure components of\ntwo colored diquarks realized as intermediate states via one gluon exchange\n(OGE) processes in hadron scattering. From the colored-diquark distributions,\nwe estimate the dominant range of gluon (color) exchanges between closely\nlocated two hadrons. We find that the colored-diquark components are enhanced\nat the short range ($\\leq$0.2 fm) and their tails show the single-exponential\ndamping. In order to distinguish the genuine colored-diquark components\noriginating in the color exchange processes from trivial colored two-quark\ncomponents contained in two color-singlet hadrons as a result of simple\ntransformation of hadronic basis, we repeat the analyses on the artificially\nconstructed gauge fields, where low- and high-momentum gluon components are\ndecoupled and only restricted pair of quarks can share and exchange\nlow-momentum gluons. We observe qualitatively the same behaviors and confirm\nthat the short-range enhancement of the colored-diquark distributions is the\ngenuine OGE-origin color excitation in hadron scattering.",
        "positive": "Mobility edge and locality of the overlap-Dirac operator with and\n  without dynamical overlap fermions: We perform a systematic study of low-lying eigenmodes of $H_w$ with various\ngauge actions to find the optimal choice for dynamical overlap fermion\nsimulations, with which one may achieve lower numerical cost for HMC and better\nlocality property of the overlap kernel. For this purpose, our study is made\nwith emphasis on the distribution of low-lying eigenvalues and the mobility\nedge with and without dynamical overlap fermions."
    },
    {
        "anchor": "Towards N=1 Super-Yang-Mills on the Lattice: We consider the lattice regularization of N=1 supersymmetric Yang--Mills\ntheory with Wilson fermions. This formulation breaks supersymmetry at any\nfinite lattice spacing; we discuss how Ward identities can be used to define a\nsupersymmetric continuum limit, which coincides with the point where the gluino\nbecomes massless. As a first step towards the understanding of the zero\ngluino-mass limit, we present results on the quenched low-lying spectrum of\nSU(2) N=1 Super-Yang--Mills, at $\\beta=2.6$ on a $V=16^3 \\times 32$ lattice, in\nthe OZI approximation. Our results, in spite of the quenched and OZI\napproximations, are in remarkable agreement with theoretical predictions in the\nsupersymmetric theory, for the states with masses which are not expected to get\na large contribution from fermion loops.",
        "positive": "Perfect and Quasi-Perfect Lattice Actions: Perfect lattice actions are exiting with several respects: they provide new\ninsight into conceptual questions of the lattice regularization, and\nquasi-perfect actions could enable a great leap forward in the non-perturbative\nsolution of QCD. We try to transmit a flavor of them, also beyond the lattice\ncommunity."
    },
    {
        "anchor": "Ward identity determination of $Z_\\mathrm{S}/Z_\\mathrm{P}$ for\n  $N_\\mathrm{f}=3$ lattice QCD in a Schr\u00f6dinger functional setup: We derive chiral Ward identities for lattice QCD with Wilson quarks and\n$N_\\mathrm{f} \\geq 3$ flavours, on small lattices with Schr\\\"odinger functional\nboundary conditions and vanishingly small quark masses. These identities relate\nthe axial variation of the non-singlet pseudoscalar density to the scalar one,\nthus enabling the non-perturbative determination of the scale-independent ratio\n$Z_\\mathrm{S}/Z_\\mathrm{P}$ of the renormalisation parameters of these\noperators. We obtain results for $N_\\mathrm{f}=3$ QCD with tree-level\nSymanzik-improved gluons and Wilson-Clover quarks, for bare gauge couplings\nwhich cover the typical range of large-volume $N_\\mathrm{f} = 2+1$ simulations\nwith Wilson fermions at lattice spacings below $0.1\\,$fm. The precision of our\nresults varies from 0.3\\% to 1\\%, except for the coarsest lattice, where it is\n2\\%. We discuss how the $Z_\\mathrm{S}/Z_\\mathrm{P}$ ratio can be used in the\nnon-perturbative calculations of $\\mathrm{O}(a)$ improved renormalised quark\nmasses.",
        "positive": "On the perturbative renormalisation of four-quark operators for new\n  physics: We discuss the renormalisation properties of the full set of $\\Delta F=2$\noperators involved in BSM processes, including the definition of RGI versions\nof operators that exhibit mixing under RG transformations. As a first step for\na fully non-perturbative determination of the scale-dependent renormalization\nfactors and their runnings, we introduce a family of appropriate Schr\\\"odinger\nFunctional schemes, and study them in perturbation theory. This allows, in\nparticular, to determine the NLO anomalous dimensions of all $\\Delta F=1,2$\noperators in these schemes. Finally, we discuss the systematic uncertainties\nrelated to the use of NLO perturbation theory for the RG running of four-quark\noperators to scales in the GeV range, in both our SF schemes and standard\n$\\overline{MS}$ and RI-MOM schemes. Large truncation effects are found for some\nof the operators considered."
    },
    {
        "anchor": "General heatbath algorithm for pure lattice gauge theory: A heatbath algorithm is proposed for pure SU(N) lattice gauge theory based on\nthe Manton action of the plaquette element for general gauge group N.\nComparison is made to the Metropolis thermalization algorithm using both the\nWilson and Manton actions. The heatbath algorithm is found to outperform the\nMetropolis algorithm in both execution speed and decorrelation rate. Results,\nmostly in D=3, for N=2 through 5 at several values for the inverse coupling are\npresented.",
        "positive": "Thermodynamics of the two--dimensional O(3) non linear sigma model with\n  Fixed-Point lattice action: We calculate the free energy density of the two dimensional O(3) non linear\nsigma model over a large temperature region. At high temperatures the\ncalculations could be done by perturbation theory whereas in the low\ntemperature regime we used Monte-Carlo simulations. Using the Fixed--Point\naction the results do not show any remarkable cut-off effects and furthermore\nthe behaviour of these effects is nearly the same over the whole temperature\nregion. The results of the Fixed-Point action are then compared to those of the\nstandard Wilson action."
    },
    {
        "anchor": "$DK$ and $D^* K$ scattering near threshold: We study the three $D_s$ quantum channels $J^P = 0^+$, $1^+$ and $2^+$ where\nexperiments have identified the charm-strange states $D^*_{s0} (2317)$,\n$D_{s1}(2460)$, $D_{s1}(2536)$ near the $DK$ and $D^*K$ thresholds, and\n$D^*_{s2}(2573)$. We consider correlation functions for sets of $\\overline q q$\noperators and, for $J^P = 0^+$, $1^+$, also the $DK$ and $D^*K$ meson-meson\ninterpolators and determine for these cases values of the elastic scattering\namplitude. Constructing the full set of correlators requires propagators which\nconnect any pair of lattice sites. For one ensemble of gauge configurations\n($32^3\\times 64$, $m_\\pi\\approx 156$ MeV) a stochastic distillation variant is\nemployed and for another ensemble ($16^3\\times 32$, $m_\\pi\\approx 266$ MeV) we\nuse the full distillation method. Both, $D^*_{s0} (2317)$ and $D_{s1}(2460)$,\nare found as bound states below threshold, whereas $D_{s1}(2536)$, and\n$D^*_{s2}(2573)$ are identified as narrow resonances close to the experimental\nmasses.",
        "positive": "Application of the Maximum Entropy Method to the (2+1)d Four-Fermion\n  Model: We investigate spectral functions extracted using the Maximum Entropy Method\nfrom correlators measured in lattice simulations of the (2+1)-dimensional\nfour-fermion model. This model is particularly interesting because it has both\na chirally broken phase with a rich spectrum of mesonic bound states and a\nsymmetric phase where there are only resonances. In the broken phase we study\nthe elementary fermion, pion, sigma and massive pseudoscalar meson; our results\nconfirm the Goldstone nature of the pi and permit an estimate of the meson\nbinding energy. We have, however, seen no signal of sigma -> pi pi decay as the\nchiral limit is approached. In the symmetric phase we observe a resonance of\nnon-zero width in qualitative agreement with analytic expectations; in addition\nthe ultra-violet behaviour of the spectral functions is consistent with the\nlarge non-perturbative anomalous dimension for fermion composite operators\nexpected in this model."
    },
    {
        "anchor": "Longitudinal and transverse spectral functions in the three-dimensional\n  O(4) model: We have performed a high statistics simulation of the O(4) model on a\nthree-dimensional lattice of linear extension L=120 for small external fields\nH. Using the maximum entropy method we analyze the longitudinal and transverse\nplane spin correlation functions for T<T_c and T>=T_c. In the transverse case\nwe find for all T and H a single sharp peak in the spectral function, whose\nposition defines the transverse mass m_T, the correlator is that of a free\nparticle with mass m_T. In the longitudinal case we find in the very high\ntemperature region also a single sharp peak in the spectrum. On approaching the\ncritical point from above the peak broadens somewhat and at T_c its position\nm_L is at 2m_T for all our H-values. Below T_c we find still a significant peak\nat omega=2m_T and at higher omega-values a continuum of states with several\nsmaller peaks with decreasing heights. This finding is in accord with a\nrelation of Patashinskii and Pokrovskii between the longitudinal and the\ntransverse correlation functions. We test this relation in the following. As a\nby-product we calculate critical exponents and amplitudes and confirm our\nformer results.",
        "positive": "Critical analysis of two-dimensional classical XY model: We consider the two-dimensional classical XY model on a square lattice in the\nthermodynamic limit using tensor renormalization group and precisely determine\nthe critical temperature corresponding to the Berezinskii-Kosterlitz-Thouless\n(BKT) phase transition to be 0.89290(5) which is an improvement compared to\nearlier studies using tensor network methods."
    },
    {
        "anchor": "SU(N) gauge theories for all N in 3 and 4 dimensions: We compare the mass spectra and string tensions of SU(2), SU(3) and SU(4)\ngauge theories in 2+1 dimensions. We find that the ratios of masses are, to a\nfirst approximation, independent of N and that the remaining dependence can be\naccurately reproduced by a simple O(1/N^2) correction. This provides us with a\nprediction of these mass ratios for all SU(N) theories in 2+1 dimensions and\ndemonstrates that these theories are `close' to N=\\infty for N\\geq 2. We also\nfind that, when expressed in units of the dynamical length scale of the theory,\nthe dimensionful coupling g^2 is proportional to 1/N at large N. We confirm\nthat these theories are indeed confining in the limit N \\to \\infty. We describe\npreliminary calculations in 3+1 dimensions which indicate that the same will be\ntrue there.",
        "positive": "On the axial-vector form factor of the nucleon and chiral symmetry: We consider the chiral Lagrangian with nucleon, isobar, and pion degrees of\nfreedom. The baryon masses and the axial-vector form factor of the nucleon are\nderived at the one-loop level. We explore the impact of using on-shell baryon\nmasses in the loop expressions. As compared to results from conventional chiral\nperturbation theory we find significant differences. An application to QCD\nlattice data is presented. We perform a global fit to the available lattice\ndata sets for the baryon masses and the nucleon axial-vector form factor, and\ndetermine the low-energy constants relevant at N$^3$LO for the baryon masses\nand at N$^2$LO for the form factor. Partial finite-volume effects are\nconsidered. We point out that the use of on-shell masses in the loops results\nin non-analytic behavior of the baryon masses and the form factor as function\nof the pion mass, which becomes prominent for larger lattice volumes than\npresently used."
    },
    {
        "anchor": "Symmetry Breaking in an Extended-O(2) Model: Motivated by attempts to quantum simulate lattice models with continuous\nAbelian symmetries using discrete approximations, we consider an extended-O(2)\nmodel that differs from the ordinary O(2) model by an explicit symmetry\nbreaking term. Its coupling allows to smoothly interpolate between the O(2)\nmodel (zero coupling) and a $q$-state clock model (infinite coupling). In the\nlatter case, a $q$-state clock model can also be defined for non-integer values\nof $q$. Thus, such a limit can also be considered as an analytic continuation\nof an ordinary $q$-state clock model to non-integer $q$. The phase diagram of\nthe extended-O(2) model in the infinite coupling limit was established in our\nprevious work, where it was shown that for non-integer $q$, there is a\nsecond-order phase transition at low temperature and a crossover at high\ntemperature. In this work, we investigate the model at finite values of the\ncoupling using Monte Carlo and tensor methods. The results may be relevant for\nconfigurable Rydberg-atom arrays.",
        "positive": "Topology and higher dimensional representations: SU(3) gauge theory in the 2-index symmetric (sextet) and fundamental\nrepresentations is considered in symmetric and periodic boxes. Using the\noverlap formulation in the quenched approximation it is shown that the\ntopological charge obtained from the sextet index theorem always leads to an\ninteger value and agrees with the charge obtained from the fundamental index\ntheorem in the continuum. At larger lattice spacing configurations exist with\nfractional topological charge if the sextet index is used but these are lattice\nartifacts and the probability of finding such a configuration rapidly\napproaches zero. By considering the decomposition of the sextet representation\nwith respect to an SU(2) subgroup it is shown that the SU(2) adjoint index\ntheorem leads to integer charge as well. We conclude that the non-zero value of\nthe bilinear gaugino condensate in N=1 super-Yang-Mills theory cannot be\nattributed to configurations with fractional topological charge once periodic\nboundary conditions are imposed."
    },
    {
        "anchor": "Casimir energy calculations within the formalism of the noncompact\n  lattice QED: A new method based on the Monte-Carlo calculation on the lattice is proposed\nto study the Casimir effect in the noncompact lattice QED. We have studied the\nstandard Casimir problem with two parallel plane surfaces (mirrors) and oblique\nboundary conditions on those as a test of our method. Physically, this boundary\nconditions may appear in the problem of modelling of the thin material films\ninteraction and are generated by additional Chern-Simons boundary term. This\napproach for the boundary condition generation is very suitable for the lattice\nformulation of the Casimir problem due to gauge invariance.",
        "positive": "Screening and Deconfinement of Sources in Finite Temperature SU(2)\n  Lattice Gauge Theory: Deconfinement and screening of higher-representation sources in\nfinite-temperature $SU(2)$ lattice gauge theory is investigated by both\nanalytical and numerical means. The effective Polyakov-line action at strong\ncoupling is simulated by an efficient cluster-updating Monte Carlo algorithm\nfor the case of $d\\!=\\!4$ dimensions. The results compare very favourably with\nan improved mean-field solution. The limit $d\\!\\to\\!\\infty$ of the $SU(2)$\ntheory is shown to be highly singular as far as critical behaviour is\nconcerned. In that limit the leading amplitudes of higher representation\nPolyakov lines vanish at strong coupling, and subleading exponents become\ndominant. Each of the higher-representation sources then effectively carry with\nthem their own critical exponents."
    },
    {
        "anchor": "The volume dependence of the long-range two-body potentials in various\n  color channels by lattice QCD: We study the color-dependent confining forces between two quarks by the\nquenched lattice simulations of Coulomb gauge QCD. The color-singlet and\ncolor-antitriplet instantaneous potentials yield attractive forces. The ratio\nof the string tensions obtained from them is approximately 2 and have little\nvolume dependence. Meanwhile, the color-octet and color-sextet channels give a\nminor contribution for two-quark system. We finally find that the infrared\nself-energy of the color-nonsinglet channels diverges in the infinite volume\nlimit; however, the degree of the divergence on the finite lattice can be\nunderstood in terms of color factors.",
        "positive": "Dyons near the transition temperature in $SU(3)$ lattice gluodynamics: We study the topological structure of $SU(3)$ lattice gluodynamics by cluster\nanalysis. This methodological study is meant as preparation for full QCD. The\ntopological charge density is becoming visible in the process of overimproved\ngradient flow, which is monitored by means of the the Inverse Participation\nRatio (IPR). The flow is stopped at the moment when calorons dissociate into\ndyons due to the overimproved character of the underlying action. This gives\nthe possibility to simultaneously detect all three dyonic constituents of KvBLL\ncalorons in the gluonic field. The behaviour of the average Polyakov loop under\n(overimproved) gradient flow could be also (as its value) a diagnostics for the\nactual phase the configuration is belonging to. Timelike Abelian monopole\ncurrents and specific patterns of the local Polyakov loop are correlated with\nthe topological clusters.The spectrum of reconstructed cluster charges $Q_{cl}$\ncorresponds to the phases. It is scattered around $Q_{cl} \\approx \\pm 1/3$ in\nthe confined phase, whereas it is $Q_{cl} \\approx \\pm 0.5 \\div 0.7$ for heavy\ndyons and $|Q_{cl}| < 0.3$ for light dyons in the deconfined phase. Heavy dyons\nare increasingly suppressed with increasing temperature. The paper is dedicated\nto the memory of Michael Mueller-Preussker who was a member of our research\ngroup for more than twenty years."
    },
    {
        "anchor": "Massless sunset diagrams in finite asymmetric volumes: This paper discusses the methods and the results used in an accompanying\npaper describing the matching of effective chiral Lagrangians in dimensional\nand lattice regularizations. We present methods to compute 2-loop massless\nsunset diagrams in finite asymmetric volumes in the framework of these\nregularizations. We also consider 1-loop sums in both regularizations,\nextending the results of Hasenfratz and Leutwyler for the case of dimensional\nregularization and we introduce a new method to calculate precisely the\nexpansion coefficients of the 1-loop lattice sums.",
        "positive": "Prediction of the $D_s^*$ width from a calculation of its radiative\n  decay in full lattice QCD: We determine the rate for $D_s^* \\rightarrow D_s \\gamma$ for the first time\nfrom lattice QCD and include the full effect of $u$, $d$ and $s$ sea quarks.\nThe valence quarks are implemented using the Highly Improved Staggered Quark\n(HISQ) formalism and we normalise the vector current nonperturbatively. We\nobtain $M(D_s^*)-M(D_s)$ of 148(4) MeV, in good agreement with experiment. The\nvalue of the decay constant of the $D_s^*$ we find to be 274(6) MeV, so that\n$f_{D_s^*}/f_{D_s} = 1.10(2)$. For the radiative decay we find $\\Gamma(D_s^*\n\\rightarrow D_s \\gamma)$ = 0.066(26) keV. Given the experimental branching\nfraction for this decay we predict a total width for the $D_s^*$ of 0.070(28)\nkeV, making this the longest lived charged vector meson."
    },
    {
        "anchor": "Two Higgs doublet dynamics at the electroweak phase transition: a\n  non-perturbative study: Using a three-dimensional (3d) effective field theory and non-perturbative\nlattice simulations, we study the MSSM electroweak phase transition with two\ndynamical Higgs doublets. We first carry out a general analysis of spontaneous\nCP violation in 3d two Higgs doublet models, finding that this part of the\nparameter space is well separated from that corresponding to the physical MSSM.\nWe then choose physical parameter values with explicit CP violation and a light\nright-handed stop, and determine the strength of the phase transition. We find\na transition somewhat stronger than in 2-loop perturbation theory, leading to\nthe conclusion that from the point of view of the non-equilibrium constraint,\nMSSM electroweak baryogenesis can be allowed even for a Higgs mass mH \\approx\n115 GeV. We also find that small values of the mass parameter mA (\\lsim 120\nGeV), which would relax the experimental constraint on mH, do not weaken the\ntransition noticeably for a light enough stop. Finally we determine the\nproperties of the phase boundary.",
        "positive": "Non-perturbative improvement of the axial current for dynamical Wilson\n  fermions: A non-perturbative determination of the axial current improvement coefficient\ncA is performed with two flavors of dynamical improved Wilson fermions and\nplaquette gauge action. The improvement condition is formulated with\nSchroedinger functional boundary conditions and enforced at constant physical\nvolume. Large sensitivity is obtained by using two different pseudo-scalar\nstates in the PCAC relation. We estimate the resulting correction to F_PS at\nbeta=5.2 to be around 10%."
    },
    {
        "anchor": "Structure of flux tube in SU(2) lattice gauge theory: The structure of the flux tube is studied in $SU(2)$ QCD from the standpoint\nof the abelian projection theory. It is shown that the flux distributions of\nthe orthogonal electric field and the magnetic field are produced by the effect\nthat the abelian monopoles in the maximally abelian (MA) gauge are expelled\nfrom the string region.",
        "positive": "Parallel Cluster Labeling for Large-Scale Monte Carlo Simulations: We present an optimized version of a cluster labeling algorithm previously\nintroduced by the authors. This algorithm is well suited for large-scale Monte\nCarlo simulations of spin models using cluster dynamics on parallel computers\nwith large numbers of processors. The algorithm divides physical space into\nrectangular cells which are assigned to processors and combines a serial local\nlabeling procedure with a relaxation process across nearest-neighbor\nprocessors. By controlling overhead and reducing inter-processor communication\nthis method attains good computational speed-up and efficiency. Large systems\nof up to 65536 X 65536 spins have been simulated at updating speeds of 11\nnanosecs/site (90.7 million spin updates/sec) using state-of-the-art\nsupercomputers. In the second part of the article we use the cluster algorithm\nto study the relaxation of magnetization and energy on large Ising models using\nSwendsen-Wang dynamics. We found evidence that exponential and power law\nfactors are present in the relaxation process as has been proposed by Hackl et\nal."
    },
    {
        "anchor": "Lattice simulations of a gauge theory with mixed adjoint-fundamental\n  matter: In this article we summarize our efforts in simulating Yang-Mills theories\ncoupled to matter fields transforming under the fundamental and adjoint\nrepresentations of the gauge group. In the context of composite Higgs\nscenarios, gauge theories with mixed representation fields have been suggested\nto describe the fundamental interactions well beyond the electroweak\nunification scale, and they are also closely related to supersymmetric QCD. In\naddition, they are studied as deformations of theories with pure adjoint matter\nin the context of adiabatic continuity. We provide some first results for bare\nparameter tuning and interdependence of the two representations. We also\ninvestigate how the chiral symmetry breaking or a conformal scenario can be\nrealized and checked in such theories.",
        "positive": "Improved currents for $\\bar{B}\\to D^{(*)}\\ell\\bar\u03bd$ form factors\n  from Oktay-Kronfeld heavy quarks: The CKM matrix element $|V_{cb}|$ can be extracted by combining\nexperimentally determined branching fractions for $\\bar{B}\\to\nD^{(*)}\\ell\\bar{\\nu}$ decays with form factors from the lattice. While\nsuccessful, the precision of this approach has been limited by heavy-quark\ndiscretization effects. An improved version of the Fermilab action, the\nOktay-Kronfeld action, can be used to reduce heavy-quark discretization effects\nin calculations performed at the physical bottom and charm quark masses.\nTreating charm and bottom quarks as massive, we are carrying out improvement of\nthe flavor-changing currents through third order in the momentum (HQET)\nexpansion."
    },
    {
        "anchor": "Magnetic-Field-Induced insulator-conductor transition in SU(2) quenched\n  lattice gauge theory: We study the correlator of two vector currents in quenched $SU\\lr{2}$ lattice\ngauge theory with a chirally invariant lattice Dirac operator with a constant\nexternal magnetic field. It is found that in the confinement phase the\ncorrelator of the components of the current parallel to the magnetic field\ndecays much slower than in the absence of a magnetic field, while for other\ncomponents the correlation length slightly decreases. We apply the maximal\nentropy method to extract the corresponding spectral function. In the limit of\nzero frequency this spectral function yields the electric conductivity of the\nquenched theory. We find that in the confinement phase the external magnetic\nfield induces nonzero electric conductivity along the direction of the field,\ntransforming the system from an insulator into an anisotropic conductor. In the\ndeconfinement phase the conductivity does not exhibit any sizable dependence on\nthe magnetic field.",
        "positive": "Chiral symmetry breaking, instantons, and monopoles: The purpose of this study is to show that monopoles induce the chiral\nsymmetry breaking. In order to indicate the evidence, we add one pair of\nmonopoles with magnetic charges to the quenched SU(3) configurations by a\nmonopole creation operator, and investigate the propaties of the chiral\nsymmetry breaking using the Overlap fermion. We show that instantons are\ncreated by the monopoles. The pseudoscalar meson mass and decay constant are\ncomputed from the correlation functions, and the renormalization constant\n$Z_{S}$ is determined by the non perturbative method. The renormalization group\ninvariant chiral condensate in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV] is\nevaluated by the Gell-Mann-Oakes-Renner formula, and the random matrix theory.\nFinally, we estimate the renormalization group invariant quark masses $\\bar{m}\n= (m_{u} + m_{d})/2$, and $m_{s}$ in $\\overline{\\mbox{MS}}$-scheme at 2 [GeV].\nThe preliminary results indicate that the chiral condensate decreases and the\nquark masses become slightly heavy by increasing the number of monopole\ncharges."
    },
    {
        "anchor": "The connected and leading disconnected diagrams of the hadronic\n  light-by-light contribution to muon $g - 2$: We report our recent lattice calculation of hadronic light-by-light\ncontribution to muon $g-2$ using our recently developed moment method. The\nconnected diagrams and the leading disconnected diagrams are included. The\ncalculation is performed on a $48^3 \\times 96$ lattice with physical pion mass\nand 5.5 fm box size. We expect sizable finite volume and finite lattice spacing\ncorrections to the results of these calculations which will be estimated in\ncalculations to be carried out over the next 1-2 years.",
        "positive": "Singular Behaviour of the Potts Model in the Thermodynamic Limit: The self-duality transformation is applied to the Fisher zeroes near the\ncritical point in the thermodynamic limit in the q>4 state Potts model in two\ndimensions. A requirement that the locus of the duals of the zeroes be\nidentical to the dual of the locus of zeroes (i) recovers the ratio of specific\nheat to internal energy discontinuity at criticality and the relationships\nbetween the discontinuities of higher cumulants and (ii) identifies duality\nwith complex conjugation. Conjecturing that all zeroes governing ferromagnetic\ncritical behaviour satisfy the latter requirement, the full locus of Fisher\nzeroes is shown to be a circle. This locus, together with the density of zeroes\nis shown to be sufficient to recover the singular form of all thermodynamic\nfunctions in the thermodynamic limit."
    },
    {
        "anchor": "Mass gap in the weak coupling limit of $(2+1)$ SU(2) lattice gauge\n  theory: We develop the dual description of $2+1$ SU(2) lattice gauge theory as\ninteracting `abelian like' electric loops by using Schwinger bosons. \"Point\nsplitting\" of the lattice enables us to construct explicit Hilbert space for\nthe gauge invariant theory which in turn makes dynamics more transparent. Using\npath integral representation in phase space, the interacting closed loop\ndynamics is analyzed in the weak coupling limit to get the mass gap.",
        "positive": "On the ground state of Yang-Mills theory: We investigate the overlap of the ground state meson potential with sets of\nmesonic-trial wave functions corresponding to different gluonic distributions.\nWe probe the transverse structure of the flux tube through the creation of\nnon-uniform smearing profiles for the string of glue connecting two color\nsources in Wilson loop operator. The non-uniformly UV-regulated flux-tube\noperators are found to optimize the overlap with the ground state and display\ninteresting features in the ground state overlap."
    },
    {
        "anchor": "The bermions: an approach to lattice QCD dynamical fermions from\n  negative flavour numbers: We estimate the effects of dynamical fermions by extrapolating to positive\nflavour numbers the results from negative values obtained by adding to the pure\ngauge sector a fermion action where the fields obey a Bose statistics: the\nbermions.",
        "positive": "Confining string and its widening in HP1 embedding approach: Structure of confining string in terms of the topological charge density and\nthe action density is studied in SU(2) Yang-Mills theory on the lattice using\nHP1 sigma-model embedding approach. We find that the confining flux tube\nnoticeably suppresses both the topological charge and the action densities.\nBeyond the string formation length the string cross section in terms of these\nquantities is well described by a Gaussian profile. In both cases the squared\nstring width is found to be a logarithmic function of the string length\nconfirming the Luscher widening of the chromoelectric string. Characteristic\nstring scales in terms of the topological and action densities are estimated as\nwell."
    },
    {
        "anchor": "Renormalization Group And Scaling Within The Microcanonical Fermionic\n  Average Approach: The MFA approach for simulations with dynamical fermions in lattice gauge\ntheories allows in principle to explore the parameters space of the theory\n(e.g. the $\\beta, m$ plane for the study of chiral condensate in QED) without\nthe need of computing the fermionic determinant at each point. We exploit this\npossibility for extracting both the renormalization group trajectories\n(\"constant physics lines\") and the scaling function, and we test it in the\nSchwinger Model. We discuss the applicability of this method to realistic\ntheories.",
        "positive": "$q\\bar{q}$-potential: a numerical study: We report the results of recent lattice simulations aimed at computing the\n$q$ and $\\bar q$ potential energies in the singlet and the octet (adjoint)\nrepresentation."
    },
    {
        "anchor": "Charmonium excited state spectrum in lattice QCD: Working with a large basis of covariant derivative-based meson interpolating\nfields we demonstrate the feasibility of reliably extracting multiple excited\nstates using a variational method. The study is performed on quenched\nanisotropic lattices with clover quarks at the charm mass. We demonstrate how a\nknowledge of the continuum limit of a lattice interpolating field can give\nadditional spin-assignment information, even at a single lattice spacing, via\nthe overlap factors of interpolating field and state. Excited state masses are\nsystematically high with respect to quark potential model predictions and,\nwhere they exist, experimental states. We conclude that this is most likely a\nresult of the quenched approximation.",
        "positive": "Update on Quarkonium Spectroscopy and $\u03b1_{strong}$ from NRQCD: NRQCD results for Upsilon and Charmonium using both dynamical and quenched\nconfigurations are presented. We investigate dependence on the light dynamical\nquark mass. Preliminary dynamical ($n_f = 2$) Charmonium data are combined with\nquenched results to extract the strong coupling constant $\\alpha_P^{(n_f)}$ for\nthe physical number of light dynamical quarks, $n_f = 3$. Good agreement is\nfound with calculations based on the Upsilon system. We show that a discrepancy\nin $\\alpha_P^{(n_f=0)}$, found between the Upsilon and Charmonium systems in\nthe quenched theory, disappears upon extrapolating to the physical number of\nflavors. Results for the strong coupling constant $\\alpha_{\\overline{MS}}$ are\npresented and sources of systematic error investigated."
    },
    {
        "anchor": "Renormalization of the momentum density on the lattice using shifted\n  boundary conditions: In order to extract transport quantities from energy-momentum-tensor (EMT)\ncorrelators in Lattice QCD there is a strong need for a non-perturbative\nrenormalization of these operators. This is due to the fact that the lattice\nregularization explicitly breaks translational invariance, invalidating the\nnon-renormalization-theorem. Here we present a non-perturbative calculation of\nthe renormalization constant of the off-diagonal components of the EMT in SU(3)\npure gauge theory using lattices with shifted boundary conditions. This allows\nus to induce a non-zero momentum in the system controlled by the shift\nparameter and to determine the normalization of the momentum density operator.",
        "positive": "S-duality in lattice super Yang-Mills: We present a progress report on studying S-duality in lattice N=4 super\nYang-Mills. This is being done through a computation of 1/2-BPS states on the\nCoulomb branch, especially the 't Hooft--Polyakov monopole and the W boson. Key\nto these calculations is the use of twisted and C-periodic boundary conditions.\nIn addition we describe a variational method to disentangle operators with\ndefinite scaling dimension, particularly the Konishi and supergravity\noperators."
    },
    {
        "anchor": "Finite density QCD with heavy quarks: In the large fermion mass limit of QCD at finite density the structure of the\npartition function greatly simplifies and can be studied analytically. We show\nthat, contrary to general wisdom, the phase of the Dirac determinant is\nrelevant only at finite temperature and can be neglected for zero temperature\nfields.",
        "positive": "Branes in the 5D Abelian Higgs Model: We find 3-brane Higgs and Coulomb phases in the 5D Abelian Higgs Model and\ndetermine the transition surfaces that separate them from the usual bulk\nphases."
    },
    {
        "anchor": "Smeared propagators for lattice hadron spectroscopy: We propose to replace ordinary propagators in lattice operator correlations\nentering the determination of hadron masses with space-time smeared\npropagators. These are defined as the inverse of the quadratic operator in the\nfermion action times its hermitian conjugate. We obtain a cleaner determination\nof hadron masses, comparable to the effect of using smeared operators.",
        "positive": "Precision Nucleon Charges and Form Factors Using 2+1-flavor Lattice QCD: We present high statistics results for the isovector nucleon charges and form\nfactors using seven ensembles of 2+1-flavor Wilson-clover fermions. The axial\nand pseudoscalar form factors obtained on each ensemble satisfy the PCAC\nrelation once the lowest energy $N\\pi$ excited state is included in the\nspectral decomposition of the correlation functions used for extracting the\nground state matrix elements. Similarly, we find evidence that the $N\\pi\\pi $\nexcited state contributes to the correlation functions with the vector current,\nconsistent with the vector meson dominance model. The resulting form factors\nare consistent with the Kelly parameterization of the experimental electric and\nmagnetic data. Our final estimates for the isovector charges are $g_{A}^{u-d} =\n1.31(06)(05)_{sys}$, $g_{S}^{u-d} = 1.06(10)(06)_{sys}$, and $g_{T}^{u-d} =\n0.95(05)(02)_{sys}$, where the first error is the overall analysis uncertainty\nand the second is an additional combined systematic uncertainty. The form\nfactors yield: (i) the axial charge radius squared, ${\\langle r_A^2\n\\rangle}^{u-d}=0.428(53)(30)_{sys}\\ {\\rm fm}^2$, (ii) the induced pseudoscalar\ncharge, $g_P^\\ast=7.9(7)(9)_{sys}$, (iii) the pion-nucleon coupling $g_{\\pi\n{\\rm NN}} = 12.4(1.2)$, (iv) the electric charge radius squared, ${\\langle\nr_E^2 \\rangle}^{u-d} = 0.85(12)(19)_{sys} \\ {\\rm fm}^2$, (v) the magnetic\ncharge radius squared, ${\\langle r_M^2 \\rangle}^{u-d} = 0.71(19)(23)_{\\rm sys}\n\\ {\\rm fm}^2$, and (vi) the magnetic moment $\\mu^{u-d} = 4.15(22)(10)_{\\rm\nsys}$. All our results are consistent with phenomenological/experimental values\nbut with larger errors. Lastly, we present a Pad\\'e parameterization of the\naxial, electric and magnetic form factors over the range $0.04< Q^2 <1$\nGeV${}^2$ for phenomenological studies."
    },
    {
        "anchor": "On the Neuberger overlap operator: We compute Neuberger's overlap operator by the Lanczos algorithm applied to\nthe Wilson-Dirac operator. Locality of the operator for quenched QCD data and\nits eigenvalue spectrum in an instanton background are studied.",
        "positive": "Layered Phase Investigations: The extra dimensional defects that are introduced to generate the lattice\nchiral zero modes are not simply a computational trick, but have interesting\nphysical consequences. After reviewing what is known about the layered phase\nthey can generate, I argue how it is possible to simulate Yang-Mills theories\nwith reduced systematic errors and speculate on how it might be possible to\nstudy the fluctuations of the layers' topological charge."
    },
    {
        "anchor": "Dynamics of Phase Transitions: The 3D 3-state Potts model: In studies of the QCD deconfining phase transition or cross-over by means of\nheavy ion experiments, one ought to be concerned about non-equilibrium effects\ndue to heating and cooling of the system. In this paper we extend our previous\nstudy of Glauber dynamics of 2D Potts models to the 3D 3-state Potts model,\nwhich serves as an effective model for some QCD properties. We investigate the\nlinear theory of spinodal decomposition in some detail. It describes the early\ntime evolution of the 3D model under a quench from the disordered into the\nordered phase well, but fails in 2D. Further, the quench leads to competing\nvacuum domains, which are difficult to equilibrate, even in the presence of a\nsmall external magnetic field. From our hysteresis study we find, as before, a\ndynamics dominated by spinodal decomposition. There is evidence that some\neffects survive in the case of a cross-over. But the infinite volume\nextrapolation is difficult to control, even with lattices as large as $120^3$.",
        "positive": "Excited-state hadron masses using the stochastic LapH method: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Large sets of spatially-extended hadron operators are used.\nThe need for multi-hadron operators in addition to single-hadron operators is\nemphasized, necessitating the use of a new stochastic method of treating the\nlow-lying modes of quark propagation which exploits Laplacian Heaviside\nquark-field smearing. A new glueball operator is tested and computing the\nmixing of this glueball operator with a quark-antiquark operator and multiple\ntwo-pion operators is shown to be feasible. Some of our initial results show\nwarning signs about extracting high-lying resonance energies using only\nsingle-hadron operators."
    },
    {
        "anchor": "Casimir effect for lattice fermions: We propose a definition of the Casimir energy for free lattice fermions. From\nthis definition, we study the Casimir effects for the massless or massive naive\nfermion, Wilson fermion, and (M\\\"obius) domain-wall fermion in $1+1$\ndimensional spacetime with the spatial periodic or antiperiodic boundary\ncondition. For the naive fermion, we find an oscillatory behavior of the\nCasimir energy, which is caused by the difference between odd and even lattice\nsizes. For the Wilson fermion, in the small lattice size of $N \\geq 3$, the\nCasimir energy agrees very well with that of the continuum theory, which\nsuggests that we can control the discretization artifacts for the Casimir\neffect measured in lattice simulations. We also investigate the dependence on\nthe parameters tunable in M\\\"obius domain-wall fermions. Our findings will be\nobserved both in condensed matter systems and in lattice simulations with a\nsmall size.",
        "positive": "The B -> D* l nu Form Factor at Zero Recoil: We describe a model independent lattice QCD method for determining the\ndeviation from unity for h_{A1}(1), the B -> D* l nu form factor at zero\nrecoil. We extend the double ratio method previously used to determine the B ->\nD l nu form factor. The bulk of statistical and systematic errors cancel in the\ndouble ratios we consider, yielding form factors which promise to reduce\npresent theoretical uncertainties in the determination of V_{cb}. We present\nresults from a prototype calculation at a single lattice spacing corresponding\nto beta=5.7."
    },
    {
        "anchor": "The Heavy-Light Spectrum from Lattice NRQCD: We present a lattice investigation of heavy-light mesons in the quenched\napproximation, using non-relativistic QCD for the heavy quark and a clover\nimproved Wilson formulation for the light quark. A comprehensive calculation of\nthe heavy-light spectrum has been performed for various heavy quark masses\naround the $b$. Our results for the $B_s-B_d$ splitting agree well with the\nexperimental value. We find the $\\Lambda_b-B$ splitting to be compatible with\nexperiment, albeit with large error bars. Our $B^*-B$ splitting is slightly\nlow, which could be explained as an effect of quenching. For the first time, we\nare able to estimate the mass of $P$ states at the $B$ and compare them with\nexperiment.",
        "positive": "The physics of eight flavours: When the flavour content of QCD is increased sufficiently, the theory\ndevelops a non-trivial infra red fixed point. Thus, for a number of flavours\nabove a certain critical value, but not yet so high that asymptotic freedom is\nlost, QCD becomes a conformal field theory. The location of the lower limit of\nthis conformal window has not yet been unequivocally determined. Using an\nimproved lattice action, and exploiting modern algorithms allowing for larger\nlattices and lower quark masses, we have shown that the theory of QCD with\neight flavours breaks chiral symmetry in the continuum. We present proof that\nthe accompanying transition is thermal in nature and as a consequence, the\nconformal window of QCD can only start afterwards, corroborating recent\nanalytical studies at the expense of older results."
    },
    {
        "anchor": "Unquenched simulations of four-nucleon interactions: Exploratory simulations of four-nucleon interactions are performed taking\ninto account the dynamical effects of internal nucleon loops. The four-nucleon\ninteractions in the isoscalar and isovector channels are described by Yukawa\ninteractions with auxiliary scalar fields. The nucleon mass and the average\nfield lengths of the scalar fields are determined as a function of nucleon\nhopping parameter and Yukawa coupling strengths. There are no problems with\n\"exceptional configurations\" at strong couplings which make quenched\nsimulations unreliable.",
        "positive": "Universal scaling and the asymptotic behaviour of Fourier coefficients\n  of the baryon-number density in QCD: We discuss the scaling of the Yang-Lee singularity (YLs) and show how the\nuniversal scaling can be used to locate phase transitions in QCD. We describe\ntwo complementary methods to extract the location of the Yang-Lee singularity\nfrom lattice QCD data of the baryon-number density and higher order cumulants\nof the baryon number, obtained at imaginary chemical potential. The first\nmethod (multi-point Pad\\'e resummation) is used to determine the Roberge-Weiss\nphase transition temperature. Our continuum extrapolated result is\n$T_{RW}=211.1\\pm3.1$ MeV. The second method is based on the asymptotic\nbehaviour of the Fourier coefficients of the baryon-number density. We discuss\nthe derivation of a fitting function and demonstrate that the procedure can\nsuccessfully locate the YLs in the Quark Meson model."
    },
    {
        "anchor": "Light quark physics from lattice QCD: I review lattice calculations of quantities that involve light quarks,\nincluding light quark masses, the vector form factor f_+(0) needed for\nsemileptonic kaon decays, and kaon mixing. Results for most of these quantities\nare now available from multiple groups. Averages of these results are\npresented, along with a discussion of the methodology behind the averaging\nprocedure. Recent progress in calculations of K->pi pi matrix elements is also\nreviewed.",
        "positive": "Berry phase in lattice QCD: We propose the lattice QCD calculation of the Berry phase which is defined by\nthe ground state of a single fermion. We perform the ground-state projection of\na single-fermion propagator, construct the Berry link variable on a\nmomentum-space lattice, and calculate the Berry phase. As the first\napplication, the first Chern number of the (2+1)-dimensional Wilson fermion is\ncalculated by the Monte Carlo simulation."
    },
    {
        "anchor": "Study of Liapunov Exponents and the Reversibility of Molecular Dynamics\n  Algorithms: We study the question of lack of reversibility and the chaotic nature of the\nequations of motion in numerical simulations of lattice QCD.",
        "positive": "Moments of Isovector Quark Distributions from Lattice QCD: We present a complete analysis of the chiral extrapolation of lattice moments\nof all twist-2 isovector quark distributions, including corrections from N pi\nand Delta pi loops. Even though the Delta resonance formally gives rise to\nhigher order non-analytic structure, the coefficients of the higher order terms\nfor the helicity and transversity moments are large and cancel much of the\ncurvature generated by the wave function renormalization. The net effect is\nthat, whereas the unpolarized moments exhibit considerable curvature, the\npolarized moments show little deviation from linearity as the chiral limit is\napproached."
    },
    {
        "anchor": "Comment on ``Lattice QCD analysis of the strangeness magnetic moment of\n  the nucleon'': The recent chirally extrapolated result of Leinweber and Thomas [Phys. Rev. D\n{\\bf 62}, 074505 (2000), or LT] for the nucleon strangeness form factor\nG_M^s(0)= -0.16 \\pm 0.18 \\mu_N differs markedly from the earlier result -0.75\n\\pm 0.30 \\mu_N obtained by Leinweber [Phys. Rev. D {\\bf 53}, 5115 (1996)] from\nthe same lattice data. An unresolved problem in the LT analysis of lattice data\nis identified and addressed. A value of G_M^s(0) = -0.55 \\pm 0.37 \\mu_N is\nobtained at R^s_d = 0.55 by extrapolating only the nucleon isoscalar lattice\ndata.",
        "positive": "Nuclear Matrix Elements for Neutrinoless Double Beta Decay from Lattice\n  QCD: While neutrino oscillation experiments have demonstrated that neutrinos have\nsmall, nonzero masses, much remains unknown about their properties and decay\nmodes. One potential decay mode --- neutrinoless double beta decay ($0 \\nu\n\\beta \\beta$) --- is a particularly interesting target of experimental\nsearches, since its observation would imply that the neutrino is a Majorana\nparticle, demonstrate that lepton number conservation is violated in nature,\nand give further constraints on the neutrino masses and mixing angles. Relating\nexperimental constraints on $0 \\nu \\beta \\beta$ decay rates to the neutrino\nmasses, however, requires theoretical input in the form of non-perturbative\nnuclear matrix elements which remain difficult to calculate reliably. In this\ntalk we will discuss progress towards first-principles calculations of relevant\nnuclear matrix elements using lattice QCD and effective field theory\ntechniques, assuming neutrinoless double beta decay mediated by a light\nMajorana neutrino. We will show preliminary results for the $\\pi^{-}\n\\rightarrow \\pi^{+} e^{-} e^{-}$ transition amplitude computed on a $16^{3}\n\\times 32$ domain wall fermion lattice with a pion mass of 420 MeV, and discuss\nimproved methods applicable to general lattice calculations of $0 \\nu \\beta\n\\beta$ decay amplitudes."
    },
    {
        "anchor": "Pseudoscalar Mass and Decay Constant in Lattice QCD with Exact Chiral\n  Symmetry: The masses and decay constants of pseudoscalar mesons $ D $, $ D_s $, and $ K\n$ are determined in quenched lattice QCD with exact chiral symmetry. For 100\ngauge configurations generated with single-plaquette action at $ \\beta = 6.1 $\non the $ 20^3 \\times 40 $ lattice, we compute point-to-point quark propagators\nfor 30 quark masses in the range $ 0.03 \\le m_q a \\le 0.80 $, and measure the\ntime-correlation functions of pseudoscalar and vector mesons. The inverse\nlattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\\pi\n$, while the strange quark bare mass ($ m_s a = 0.08 $), and the charm quark\nbare mass ($ m_c a = 0.80 $) are fixed such that the masses of the\ncorresponding vector mesons are in good agreement with $ \\phi(1020) $ and $\nJ/\\psi(3097) $ respectively. Our results of pseudoscalar-meson decay constant\nare: $ f_K = 152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} =\n266(10)(18) $ MeV [hep-ph/0506266]. The latest experimental result of $ f_{D^+}\n$ from CLEO [hep-ex/0508057] is in good agreement with our prediction.",
        "positive": "Mesonic decay constants in lattice NRQCD: Lattice NRQCD with leading finite lattice spacing errors removed is used to\ncalculate decay constants of mesons made up of heavy quarks. Quenched\nsimulations are done with a tadpole improved gauge action containing plaquette\nand six-link rectangular terms. The tadpole factor is estimated using the\nLandau link. For each of the three values of the coupling constant considered,\nquarkonia are calculated for five masses spanning the range from charmonium\nthrough bottomonium, and one set of quark masses is tuned to the B(c).\n\"Perturbative\" and nonperturbative meson masses are compared. One-loop\nperturbative matching of lattice NRQCD with continuum QCD for the heavy-heavy\nvector and axial vector currents is performed. The data are consistent with the\nvector meson decay constants of quarkonia being proportional to the square root\nof their mass and the B(c) decay constant being equal to 420(13) MeV."
    },
    {
        "anchor": "Chiral Transition via Strong Coupling Expansion: We investigate the chiral transition of $U(3)$ lattice gauge theory based on\nthe strong coupling expansion. A generalized vertex model with vertices and\nweights derived from the tensor network approach of the dual representation of\nlattice QCD with staggered fermions is used and the configurations are sampled\nby the Metropolis algorithm. We study the chiral transition in the chiral limit\nand focus on the dependence of the second-order chiral transition temperature\n$aT_c$ for different values of the lattice gauge coupling $\\beta$. We compare\ndifferent orders of truncations of the strong coupling expansion:\n$Ord(\\beta^0)$, $Ord(\\beta^1)$, and $Ord(\\beta^2)$. We comment on the prospects\nof extending to $SU(3)$ at finite density.",
        "positive": "The random lattice as a regularization scheme: A semi-analytic method to compute the first coefficients of the\nrenormalization group functions on a random lattice is introduced. It is used\nto show that the two-dimensional $O(N)$ non-linear $\\sigma$-model regularized\non a random lattice has the correct continuum limit. A degree $\\kappa$ of\n``randomness'' in the lattice is introduced and an estimate of the ratio\n$\\Lambda_{random}/\\Lambda_{regular}$ for two rather opposite values of $\\kappa$\nin the $\\sigma$-model is also given. This ratio turns out to depend on\n$\\kappa$."
    },
    {
        "anchor": "Chiral perturbation theory for three-flavour lattice QCD with isospin\n  splitting: An important tool for the analysis of results of numerical simulations of\nlattice QCD is chiral perturbation theory. In Wilson chiral perturbation theory\nthe effects of the finite lattice spacing $a$ are taken into account. In recent\nyears the effects of isospin splitting on the masses of hadrons have been\ninvestigated in Monte Carlo simulations. Correspondingly, in this article we\nderive the expansions of the masses of the pseudoscalar mesons in chiral\nperturbation theory at next-to-leading order for twisted mass lattice QCD with\nthree light quark flavours, taking the mass difference between the up and down\nquarks into account. The results include terms up to orders $m_q^2$ in the\nquark masses, $\\Delta m^2$ in the mass splitting between up- and down quarks,\nand $a^2$ in the lattice spacing, respectively.",
        "positive": "Hadron correlators with improved fermions: We investigate point-to-point correlation functions for various mesonic and\nbaryonic channels using the ${\\cal O}(a)$-improved Wilson action due to\nSheikholeslami and Wohlert. We consider propagators to both time slices 0 and\n1. We find that discretisation effects are more pronounced than those reported\nwith unimproved Wilson fermions, but that the same procedure for removing\nfinite size effects is successful. Extrapolating to the chiral limit, we see\nthe notable features predicted phenomenologically: the ratio of interacting to\nfree correlators in the vector channel is roughly constant to about 1 fm, while\nin the pseudoscalar channel the ratio increases markedly due to the strong\nbinding."
    },
    {
        "anchor": "Finite-size scaling of the quark condensate in quenched lattice QCD: We confront the finite volume and small quark mass behaviour of the scalar\ncondensate, determined numerically in quenched lattice QCD using Neuberger\nfermions, with predictions of quenched chiral perturbation theory. We find that\nquenched chiral perturbation theory describes the numerical data well, allowing\nus to extract the infinite volume, chiral limit scalar condensate, up to a\nmultiplicative renormalization constant.",
        "positive": "Spectrum and Bethe-Salpeter amplitudes of $\u03a9$ baryons from lattice\n  QCD: The $\\Omega$ baryons with $J^P=3/2^\\pm, 1/2^\\pm$ are studied on the lattice\nin the quenched approximation. Their mass levels are ordered as\n$M_{3/2^+}<M_{3/2^-}\\approx M_{1/2^-}<M_{1/2^+}$, as is expected from the\nconstituent quark model. The mass values are also close to those of the four\n$\\Omega$ states observed in experiments, respectively. We calculate the\nBethe-Salpeter amplitudes of $\\Omega(3/2^+)$ and $\\Omega(1/2^+)$ and find there\nis a radial node for the $\\Omega(1/2^+)$ Bethe-Salpeter amplitude, which may\nimply that $\\Omega(1/2^+)$ is an orbital excitation of $\\Omega$ baryons as a\nmember of the $(D,L_N^P)=(70,0_2^+)$ supermultiplet in the $SU(6)\\bigotimes\nO(3)$ quark model description. Our results are helpful for identifying the\nquantum number of experimentally observed $\\Omega$ states."
    },
    {
        "anchor": "Topological Charge and The Spectrum of Exactly Massless Fermions on the\n  Lattice: The square root of the positive definite hermitian operator $D_w^{\\dagger}\nD_w$ in Neuberger's proposal of exactly massless quarks on the lattice is\nimplemented by the recursion formula $Y_{k+1} = {1/2} (Y_k + D_w^{\\dagger} D_w\nY_k^{-1})$ with $Y_0 = \\Id$, where $Y_k^2$ converges to $D_w^{\\dagger} D_w$\nquadratically. The spectrum of the lattice Dirac operator for single massless\nfermion in two dimensional background U(1) gauge fields is investigated. For\nsmooth background gauge fields with non-zero topological charge, the exact zero\nmodes with definite chirality are reproduced to a very high precision on a\nfinite lattice and the Index Theorem is satisfied exactly. The fermionic\ndeterminants are also computed and they are in good agreement with the\ncontinuum exact solution.",
        "positive": "The U_A(1) Problem on the Lattice with Ginsparg-Wilson Fermions: We show how it is possible to give a precise and unambiguous implementation\nof the Witten--Veneziano formula for the eta' mass on the lattice, which looks\nlike the formal continuum one, if the expression of the topological charge\ndensity operator, suggested by fermions obeying the Ginsparg--Wilson relation,\nis employed. By using recent numerical results from simulations with overlap\nfermions in 2 (abelian Schwinger model) and 4 (QCD) dimensions, one obtains\nvalues for the mass of the lightest pseudo-scalar flavour-singlet state that\nagree within errors with theoretical expectations and experimental data,\nrespectively."
    },
    {
        "anchor": "Learning trivializing flows: The recent introduction of machine learning techniques, especially\nnormalizing flows, for the sampling of lattice gauge theories has shed some\nhope on improving the sampling efficiency of the traditional HMC algorithm.\nNaive use of normalizing flows has been shown to lead to bad scaling with the\nvolume. In this talk we propose using local normalizing flows at a scale given\nby the correlation length. Even if naively these transformations have a small\nacceptance, when combined with the HMC algorithm lead to algorithms with high\nacceptance, and also with reduced autocorrelation times compared with HMC.\nSeveral scaling tests are performed in the $\\phi^{4}$ theory in 2D.",
        "positive": "On lattice actions for static quarks: We introduce new discretizations of the action for static quarks. They\nachieve an exponential improvement (compared to the Eichten-Hill\nregularization) on the signal to noise ratio in static-light correlation\nfunctions. This is explicitly checked in a quenched simulation and it is\nunderstood quantitatively in terms of the self energy of a static quark and the\nlattice heavy quark potential at zero distance. We perform a set of scaling\ntests in the Schroedinger functional and find scaling violations in the O(a)\nimproved theory to be rather small -- for one observable significantly smaller\nthan with the Eichten-Hill regularization. In addition we compute the\nimprovement coefficients of the static light axial current up to O(g_0^4)\ncorrections and the corresponding renormalization constants non-perturbatively.\nThe regularization dependent part of the renormalization of the b-quark mass in\nstatic approximation is also determined."
    },
    {
        "anchor": "Finite-Size Effect of Hadron Masses with Kogut-Susskind Quarks: We present numerical results and their analyses of finite-size effects of\nhadron masses for both quenched and full QCD calculations. We show that they\nare much larger for full QCD due to dynamical sea quarks and the associated\nbreaking of $Z(3)$ symmetry. We also argue that finite-size effects are\nnon-negligible even for the largest lattice size simulation currently being\nmade for a very small quark mass. (talk at lattice93)",
        "positive": "Adaptive multigrid algorithm for the lattice Wilson-Dirac operator: We present an adaptive multigrid solver for application to the non-Hermitian\nWilson-Dirac system of QCD. The key components leading to the success of our\nproposed algorithm are the use of an adaptive projection onto coarse grids that\npreserves the near null space of the system matrix together with a simplified\nform of the correction based on the so-called gamma_5-Hermitian symmetry of the\nDirac operator. We demonstrate that the algorithm nearly eliminates critical\nslowing down in the chiral limit and that it has weak dependence on the lattice\nvolume."
    },
    {
        "anchor": "Local bilinear operators on the lattice and their perturbative\n  renormalisation including O(a) effects: Some basic concepts are discussed to derive renormalisation factors of local\nlattice operators relevant to deep inelastic structure functions and to other\nmeasurable quantities. These $Z$ factors can be used to relate matrix elements\nmeasured by lattice techniques to their continuum counterparts. We discuss the\n$O(a)$ improvement of point and one-link lattice quark operators. Suitable\nbases of improved operators are derived. Tadpole improvement is applied to get\nmore reliable perturbative results.",
        "positive": "Monte Carlo Study of Pure-Phase Cumulants of 2D q-State Potts Models: We performed Monte Carlo simulations of the two-dimensional q-state Potts\nmodel with q=10, 15, and 20 to study the energy and magnetization cumulants in\nthe ordered and disordered phase at the first-order transition point $\\beta_t$.\nBy using very large systems of size 300 x 300, 120 x 120, and 80 x 80 for q=10,\n15, and 20, respectively, our numerical estimates provide practically (up to\nunavoidable, but very small statistical errors) exact results which can serve\nas a useful test of recent resummed large-q expansions for the energy cumulants\nby Bhattacharya `et al.' [J. Phys. I (France) 7 (1997) 81]. Up to the third\norder cumulant and down to q=10 we obtain very good agreement, and also the\nhigher-order estimates are found to be compatible."
    },
    {
        "anchor": "Automatically generating Feynman rules for improved lattice field\n  theories: Deriving the Feynman rules for lattice perturbation theory from actions and\noperators is complicated, especially when improvement terms are present. This\nphysically important task is, however, suitable for automation. We describe a\nflexible algorithm for generating Feynman rules for a wide range of lattice\nfield theories including gluons, relativistic fermions and heavy quarks. We\nalso present an efficient implementation of this in a freely available,\nmulti-platform programming language (\\python), optimised to deal with a wide\nclass of lattice field theories.",
        "positive": "Two-loop Wess-Zumino model with exact supersymmetry on the lattice: We consider a lattice formulation of the four dimensional N=1 Wess-Zumino\nmodel in terms of the Ginsparg-Wilson relation. This formulation has an exact\nsupersymmetry on the lattice. The lattice action is invariant under a deformed\nsupersymmetric transformation which is non-linear in the scalar fields and it\nis determined by an iterative procedure in the coupling constant to all orders\nin perturbation theory. We also show that the corresponding Ward-Takahashi\nidentity is satisfied at fixed lattice spacing. The calculation is performed in\nlattice perturbation theory up to order $g^3$ (two-loop) and the Ward-Takahashi\nidentity (containing 110 connected non-tadpole Feynman diagrams) is satisfied\nat fixed lattice spacing thanks to this exact lattice supersymmetry."
    },
    {
        "anchor": "Dimensional reduction in QCD: Lessons from lower dimensions: In this contribution we present the results of a series of investigations of\ndimensional reduction, applied to SU(3) gauge theory in 2 + 1 dimensions. We\nreview earlier results, present a new reduced model with Z(3) symmetry, and\ndiscuss the results of numerical simulations of this model.",
        "positive": "Computation of hybrid static potentials from optimized trial states in\n  SU(3) lattice gauge theory: We compute hybrid static potentials in SU(3) lattice gauge theory using a\nmethod to automatically generate a large set of suitable creation operators\nfrom elementary building blocks. This method allows to find sets of creation\noperators, which generate trial states with large ground state overlaps for all\ninvestigated angular momentum and parity sectors. We present numerical results\nfor hybrid static potentials with quantum numbers $\\Sigma^-_g, \\Sigma^+_u,\n\\Sigma^-_u, \\Pi_g, \\Pi_u, \\Delta_g, \\Delta_u$."
    },
    {
        "anchor": "N_f=2 chiral dynamics in the mixed chiral regime: We present a study of the pseudoscalar propagator in the mixed chiral regime\nwith valence quark masses in the \\epsilon-regime and sea quark masses in the\np-regime. We first show the NNLO prediction of this observable in the chiral\nexpansion. In sectors of fixed topology, the correlator has a pole in 1/m_v^2\nthat can be matched to the topological zero-mode contributions to the\ncorrelator. We compute the residue of this pole in a N_f=2 mixed-action\nsimulation and compare the results with the prediction in Chiral Perturbation\nTheory.",
        "positive": "On two dimensional non-abelian chiral lattice gauge theories in\n  Ginsparg-Wilson formalism: Defining chiral lattice gauge theories in the Ginsparg-Wilson formalism is\ncomplicated by the so-called fermion measure problem. It has been proven for\nthe abelian theories that smooth well-behaved fermion measure exists if and\nonly if the anomaly-free condition is granted, and the same was shown to hold\nin perturbative theories for non-abelian gauge groups, but the non-perturbative\nproof is absent. In this paper, we consider a simpler problem in 2-d and\npresent a proof for the existence of smooth and gauge invariant fermion measure\non the gauge field configuration space with zero field strengths for arbitrary\ncompact Lie groups, provided the anomaly-free conditions are satisfied. It is\nconjectured that such consideration is sufficient for the unknown full proof."
    },
    {
        "anchor": "Worldline approach to few-body physics on the lattice: We study the physics of two species of non-relativistic hard-core bosons with\nattractive or repulsive delta function interactions on a spacetime lattice\nusing the worldline formulation. By tuning the chemical potential carefully we\nshow that worm algorithms can efficiently sample the worldline configurations\nin any fixed particle-number sector. Since fermions can be treated as hard-core\nbosons up to a permutation sign, we also apply this approach to\nnon-relativistic fermions. The fermion permutation sign is treated as an\nobservable in this approach and can be used to extract energies for each\nparticle-number sector. Since in one dimension non-relativistic fermions can\nonly permute due to boundary effects, unlike the auxiliary field method, in\nmany cases our approach does not suffer from sign problems. Using our method we\ndiscover limitations of the recently proposed complex Langevin calculations in\none dimension.",
        "positive": "International Lattice Data Grid: We propose the co-ordination of lattice QCD grid developments in different\ncountries to allow transparent exchange of gauge configurations in future,\nshould participants wish to do so. We describe briefly UKQCD's XML schema for\nlabelling and cataloguing the data. A meeting to further develop these ideas\nwill be held in Edinburgh on 19/20 December 2002, and will be available over\nAccessGrid."
    },
    {
        "anchor": "Ghost Sector in Minimal Linear Covariant Gauge: We discuss possible definitions of the Faddeev-Popov matrix for the minimal\nlinear covariant gauge on the lattice and present preliminary results for the\nghost propagator.",
        "positive": "Temporal correlator in YM^2_3 and reflection-positivity violation: We consider numerical data for the lattice Landau gluon propagator obtained\nat very large lattice volumes in three-dimensional pure SU(2) Yang-Mills gauge\ntheory (YM^2_3). We find that the temporal correlator C(t) shows an oscillatory\npattern and is negative for several values of t. This is an explicit violation\nof reflection positivity and can be related to gluon confinement. We also\nobtain a good fit for this quantity in the whole time interval using a sum of\nStingl-like propagators."
    },
    {
        "anchor": "Axion cosmology, lattice QCD and the dilute instanton gas: Axions are one of the most attractive dark matter candidates. The evolution\nof their number density in the early universe can be determined by calculating\nthe topological susceptibility $\\chi(T)$ of QCD as a function of the\ntemperature. Lattice QCD provides an ab initio technique to carry out such a\ncalculation. A full result needs two ingredients: physical quark masses and a\ncontrolled continuum extrapolation from non-vanishing to zero lattice spacings.\nWe determine $\\chi(T)$ in the quenched framework (infinitely large quark\nmasses) and extrapolate its values to the continuum limit. The results are\ncompared with the prediction of the dilute instanton gas approximation (DIGA).\nA nice agreement is found for the temperature dependence, whereas the overall\nnormalization of the DIGA result still differs from the non-perturbative\ncontinuum extrapolated lattice results by a factor of order ten. We discuss the\nconsequences of our findings for the prediction of the amount of axion dark\nmatter.",
        "positive": "Universal continuum limit of non-perturbative lattice non-singlet moment\n  evolution: We present evidence for the universality of the continuum limit of the scale\ndependence of the renormalization constant associated with the operator\ncorresponding to the average momentum of non-singlet parton densities. The\nevidence is provided by a non-perturbative computation in quenched lattice QCD\nusing the Schr\\\"odinger Functional scheme. In particular, we show that the\ncontinuum limit is independent of the form of the fermion action used, i.e. the\nWilson action and the non-perturbatively improved clover action."
    },
    {
        "anchor": "openQ*D simulation code for QCD+QED: The openQ*D code for the simulation of QCD+QED with C$^\\star$ boundary\nconditions is presented. This code is based on openQCD-1.6, from which it\ninherits the core features that ensure its efficiency: the locally-deflated\nSAP-preconditioned GCR solver, the twisted-mass frequency splitting of the\nfermion action, the multilevel integrator, the 4th order OMF integrator, the\nSSE/AVX intrinsics, etc. The photon field is treated as fully dynamical and\nC$^\\star$ boundary conditions can be chosen in the spatial directions. We\ndiscuss the main features of openQ*D, and we show basic test results and\nperformance analysis. An alpha version of this code is publicly available and\ncan be downloaded from http://rcstar.web.cern.ch/ .",
        "positive": "Nonperturbative HQET at Order $1/m$: We summarize first results for masses and decay constants of bottom-strange\n(pseudo-scalar and vector) mesons from nonperturbatively renormalized\nheavy-quark effective theory (HQET), using lattice-QCD simulations in the\nquenched approximation."
    },
    {
        "anchor": "Marginally stable solutions: In previous work constant magnetic field strength solutions for SU(2) gauge\ntheory on a torus were found, which somewhat surprisingly turned out to be\nclassically stable. This was called marginal stability, as moving along one of\nits zero-modes, two of the stable modes turn unstable. Here we investigate the\nstability under quantum fluctuations in the domain where the solutions possess\nthe marginal stability at the classical level.",
        "positive": "de Sitter gravity from lattice gauge theory: We investigate a lattice model for Euclidean quantum gravity based on\ndiscretization of the Palatini formulation of General Relativity. Using Monte\nCarlo simulation we show that while a naive approach fails to lead to a vacuum\nstate consistent with the emergence of classical spacetime, this problem may be\nevaded if the lattice action is supplemented by an appropriate counter term. In\nthis new model we find regions of the parameter space which admit a ground\nstate which can be interpreted as (Euclidean) de Sitter space."
    },
    {
        "anchor": "The Microscopic Dirac Operator Spectrum: We review the exact results for microscopic Dirac operator spectra based on\neither Random Matrix Theory, or, equivalently, chiral Lagrangians. Implications\nfor lattice calculations are discussed.",
        "positive": "Generalized quark number susceptibilities from fugacity expansion at\n  finite chemical potential for $N_f$ = 2 Wilson fermions: Generalized susceptibilities of the net quark number have been proposed to be\ngood probes for the transitions in the QCD phase diagram and for the search of\na possible critical end point. In this article we explore a new strategy for\ncomputing quark number susceptibilities from lattice QCD via an expansion in\nthe fugacity parameter $e^{\\mu\\beta}$. All quark number related bulk\nobservables are particularly easy to access in this approach and we present\nresults for generalized quark number susceptibilities up to 4-th order. Ratios\nof these quantities are studied and compared with model calculations for the\nhigh- and low temperature regions up to a chemical potential of\n$\\mu\\beta\\approx1.0$."
    },
    {
        "anchor": "Lattice QCD, gauge fixing, and the transition to the perturbative regime: Perturbative QCD uses the Faddeev-Popov gauge-fixing procedure, which leads\nto ghosts and the local BRST invariance of the gauge-fixed perturbative QCD\naction. In the asymptotic regime, where perturbative QCD is relevant, Gribov\ncopies can be neglected. In the nonperturbative regime, one must adopt either a\nnonlocal Gribov-copy free gauge (e.g., Laplacian gauge) or attempt to maintain\nlocal BRST invariance at the expense of admitting Gribov copies. These issues\nare explored and discussed. In addition, the relationship between recent\nDyson-Schwinger based calculations of the infrared behavior of QCD Green's\nfunctions and the lattice calculation of these quantities is examined.",
        "positive": "Twist two operators at finite volume: We calculate the volume corrections to the two-pion matrix element of twist\ntwo operators."
    },
    {
        "anchor": "Finite Volume Dependence of Hadron Properties and Lattice QCD: Because the time needed for a simulation in lattice QCD varies at a rate\nexceeding the fourth power of the lattice size, it is important to understand\nhow small one can make a lattice without altering the physics beyond\nrecognition. It is common to use a rule of thumb that the pion mass times the\nlattice size should be greater than (ideally much greater than) four (i.e.,\n$m_\\pi L \\gg 4$). By considering a relatively simple chiral quark model we are\nled to suggest that a more realistic constraint would be $m_\\pi (L - 2R) \\gg\n4$, where $R$ is the radius of the confinement region, which for these purposes\ncould be taken to be around 0.8-1.0 fm. Within the model we demonstrate that\nviolating the second condition can lead to unphysical behaviour of hadronic\nproperties as a function of pion mass. In particular, the axial charge of the\nnucleon is found to decrease quite rapidly as the chiral limit is approached.",
        "positive": "Multigrid for Staggered Lattice Fermions: Critical slowing down in Krylov methods for the Dirac operator presents a\nmajor obstacle to further advances in lattice field theory as it approaches the\ncontinuum solution. Here we formulate a multi-grid algorithm for the\nKogut-Susskind (or staggered) fermion discretization which has proven difficult\nrelative to Wilson multigrid due to its first-order anti-Hermitian structure.\nThe solution is to introduce a novel spectral transformation by the\nK\\\"ahler-Dirac spin structure prior to the Galerkin projection. We present\nnumerical results for the two-dimensional, two-flavor Schwinger model, however,\nthe general formalism is agnostic to dimension and is directly applicable to\nfour-dimensional lattice QCD."
    },
    {
        "anchor": "Baryon bags in strong coupling QCD: We discuss lattice QCD with one flavor of staggered fermions and show that in\nthe path integral the baryon contributions can be fully separated from quark\nand diquark contributions. The baryonic degrees of freedom are independent of\nthe gauge field and the corresponding free fermion action describes the baryons\nthrough the joint propagation of three quarks. The non-baryonic dynamics is\ndescribed by quark and diquark terms that couple to the gauge field. When\nevaluating the quark and diquark contributions in the strong coupling limit the\npartition function completely factorizes into baryon bags and a complementary\ndomain. Baryon bags are regions in space-time where the dynamics is described\nby a single free fermion made out of three quarks propagating coherently as a\nbaryon. Outside the baryon bags the relevant degrees of freedom are monomers\nand dimers for quarks and diquarks. The partition sum is a sum over all baryon\nbag configurations and for each bag a free fermion determinant appears as a\nweight factor.",
        "positive": "Chiral restoration and deconfinement in two-color QCD with two flavors\n  of staggered quarks: In preparation of lattice studies of the two-color QCD phase diagram we study\nchiral restoration and deconfinement at finite temperature with two flavors of\nstaggered quarks using an RHMC algorithm on GPUs. We first study unquenching\neffects in local Polyakov loop distributions, and the Polyakov loop potential\nobtained via Legendre transformation, in a fixed-scale approach for heavier\nquarks. We also present the chiral condensate and the corresponding\nsusceptibility over the lattice coupling across the chiral transition for\nlighter quarks. Using Ferrenberg-Swendsen reweighting we extract the maxima of\nthe chiral susceptibility in order to determine pseudo-critical couplings on\nvarious lattices suitable for chiral extrapolations. These are then used to fix\nthe relation between coupling and temperature in the chiral limit."
    },
    {
        "anchor": "Excited baryons from Bayesian priors and overlap fermions: Using the constrained-fitting method based on Bayesian priors, we extract the\nmasses of the two lowest states of octet and decuplet baryons with both\nparities. The calculation is done on quenched 16^3x28 lattices of a=0.2 fm\nusing an improved gauge action and overlap fermions, with the pion mass as low\nas 180 MeV. The Roper state N(1440)1/2+ is clearly observed for the first time\nas the 1st-excited state of the nucleon from the standard interpolating field.\nTogether with other baryons, our preliminary results indicate that the\nlevel-ordering of the low-lying baryon states on the lattice is largely\nconsistent with experiment. The realization is helped by cross-overs between\nthe excited 1/2+ and 1/2- states in the region of pion mass from 300 to 400\nMeV.",
        "positive": "Effective Lattice Actions for Finite-Temperature Yang-Mills Theory: We determine effective lattice actions for the Polyakov loop using inverse\nMonte Carlo techniques."
    },
    {
        "anchor": "Determination of the quark condensate from heavy-light current-current\n  correlators in full lattice QCD: We derive the Operator Product Expansion whose vacuum expectation value gives\nthe time-moments of the pseudoscalar heavy-light current-current correlator up\nto and including terms in $\\alpha_s^2$ multiplying\n$\\langle\\overline{\\psi}\\psi\\rangle/M^3$ and terms in $\\alpha_s$ multiplying\n$\\langle \\alpha_s G^2 \\rangle/M^4$, where $M$ is the heavy-quark mass. Using\nlattice QCD results for heavy-strange correlators obtained for a variety of\nheavy quark masses on gluon field configurations including $u$, $d$ and $s$\nquarks in the sea at three values of the lattice spacing, we are able to show\nthat the contribution of the strange-quark condensate to the time-moments is\nvery substantial. We use our lattice QCD time-moments and the OPE to determine\na value for the condensate, fitting the 4th, 6th, 8th and 10th time-moments\nsimultaneously. Our result, $\\langle \\overline{s}s\n\\rangle^{\\overline{\\text{MS}}}(2 \\text{GeV}) = -(296(11) \\,\\mathrm{MeV})^3$,\nagrees well with HPQCD's earlier, more direct, lattice QCD\ndetermination~\\cite{McNeile:2012xh}. As well as confirming that the $s$ quark\ncondensate is close in value to the light quark condensate, this demonstrates\nclearly the consistency of the Operator Product Expansion for fully\nnonperturbative calculations of matrix elements of short-distance operators in\nlattice QCD.",
        "positive": "Monte Carlo calculations of the finite density Thirring model: We present results of the numerical simulation of the two-dimensional\nThirring model at finite density and temperature. The severe sign problem is\ndealt with by deforming the domain of integration into complex field space.\nThis is the first example where a fermionic sign problem is solved in a quantum\nfield theory by using the holomorphic gradient flow approach, a generalization\nof the Lefschetz thimble method."
    },
    {
        "anchor": "Digitising SU(2) Gauge Fields and the Freezing Transition: Efficient discretisations of gauge groups are crucial with the long term\nperspective of using tensor networks or quantum computers for lattice gauge\ntheory simulations. For any Lie group other than U$(1)$, however, there is no\nclass of asymptotically dense discrete subgroups. Therefore, discretisations\nlimited to subgroups are bound to lead to a freezing of Monte Carlo simulations\nat weak couplings, necessitating alternative partitionings without a group\nstructure. In this work we provide a comprehensive analysis of this freezing\nfor all discrete subgroups of SU$(2)$ and different classes of asymptotically\ndense subsets. We find that an appropriate choice of the subset allows unfrozen\nsimulations for arbitrary couplings, though one has to be careful with varying\nweights of unevenly distributed points. A generalised version of the Fibonacci\nspiral appears to be particularly efficient and close to optimal.",
        "positive": "Reflection positive formulation of chiral gauge theories on a lattice: Gauge invariant chiral theories satisfying the reflection positivity is\nconstructed on a lattice. This requires the introduction of \"half gauge fields\"\ndefined some time ago by Brydges, Fr\\\"{o}hlich, and Seiler \\cite{BFS}. A\ntwo-dimensional model is considered in some detail."
    },
    {
        "anchor": "Numerical Simulations and the Strength of the Electroweak Phase\n  Transition: Numerical simulations are performed to study the finite temperature phase\ntransition in the SU(2) Higgs model on the lattice. The strength of the first\norder phase transition is investigated by determining the latent heat and the\ninterface tension on $L_t=2$ lattices. The values of the Higgs boson mass\npresently chosen are below 50 GeV. Our results are in qualitative agreement\nwith two-loop resummed perturbation theory.",
        "positive": "Radiative Corrections to the Kinetic Couplings in Nonrelativistic\n  Lattice QCD: The heavy-quark mass and wave function renormalizations, energy shift, and\nradiative corrections to two important couplings, the so-called kinetic\ncouplings, in nonrelativistic lattice QCD are determined to leading order in\ntadpole-improved perturbation theory. The scales at which to evaluate the\nrunning QCD coupling for these quantities, except the wave function\nrenormalization, are obtained using the Lepage-Mackenzie prescription. When the\nbare quark mass is greater than the inverse lattice spacing, the kinetic\ncoupling corrections are roughly 10\\% of the tree-level coupling strengths;\nthese corrections grow quickly as the bare quark mass becomes small. A need for\ncomputing the two-loop corrections to the energy shift and mass renormalization\nis demonstrated."
    },
    {
        "anchor": "Chern-Simons term in the 4-dimensional SU(2) Higgs Model: Using Seiberg's definition for the geometric charge in SU(2) lattice gauge\ntheory, we have managed to apply it also to the Chern-Simons term. We checked\nthe periodic structure and determined the Chern-Simons density on small\nlattices $L^4$ and $L^3 \\times 2,\\, 4$ with $L=4,\\, 6,\\mbox{ and }8$ near the\ncritical region in the SU(2) Higgs model. The data indicate that tunneling is\nincreased at high temperature.",
        "positive": "Connecting Lattice QCD with Chiral Perturbation Theory at Strong\n  Coupling: We study the difficulties associated with detecting chiral singularities\npredicted by chiral perturbation theory (ChPT) in lattice QCD. We focus on the\nphysics of the remnant O(2) chiral symmetry of staggered fermions in the strong\ncoupling limit using the recently discovered directed path algorithm. Since it\nis easier to look for power-like singularities as compared to logarithmic ones,\nour calculations are performed at a fixed finite temperature in the chirally\nbroken phase. We show that the behavior of the chiral condensate, the pion mass\nand the pion decay constant, for small masses, are all consistent with the\npredictions of ChPT.\n  However, the values of the quark masses that we need to demonstrate this are\nmuch smaller than those being used in dynamical QCD simulations. We also need\nto use higher order terms in the chiral expansion to fit our data."
    },
    {
        "anchor": "Higgs mechanism near the 5d bulk phase transition: We present a non-perturbative model of Gauge-Higgs Unification. We consider a\nfive-dimensional pure SU(2) gauge theory with orbifold boundary conditions\nalong the fifth dimension, such that the symmetry is reduced to U(1) at the\nfixed points of the orbifold action. The spectrum on the four-dimensional\nboundary hyperplanes includes, apart from the U(1) gauge boson, also a complex\nscalar, interpreted as a simplified version of the Standard Model Higgs field.\nThe gauge theory is defined on a Euclidean lattice which is anisotropic in the\nextra dimension. Using the boundary Wilson Loop and the observable that\nrepresents the scalar and in the context of an expansion in fluctuations around\na Mean-Field background, we show that a) near the bulk phase transition the\nmodel tends to reduce dimensionally to a four-dimensional gauge-scalar theory,\nb) the boundary U(1) gauge symmetry breaks spontaneously due to the broken\ntranslational invariance along the fifth dimension, c) it is possible to\nconstruct renormalized trajectories on the phase diagram along which the Higgs\nmass is constant as the lattice spacing is varied, d) by taking a continuum\nlimit in the regime where the anisotropy parameter is small, it is possible to\npredict the existence of a Z' state with a mass around 1 TeV.",
        "positive": "Clustering of Monopoles in the Instanton Vacuum: We generate a random instanton vacuum with various densities and size\ndistributions. We perform numerically the maximally abelian gauge fixing of\nthese configurations in order to find monopole trajectories induced by\ninstantons. We find that instanton-induced monopole loops form enormous\nclusters occupying the whole physical volume, provided instantons are\nsufficiently dense. It indicates that confinement might be caused by\ninstantons."
    },
    {
        "anchor": "The Light Quark Masses with the Wilson Quark Action using Chiral Ward\n  Identities: We present results for the light quark masses for the Wilson quark action\nobtained with the PCAC relation for the one-link extended axial vector current\nin quenched QCD at $\\beta=5.9-6.5$. This method leads to a remarkable\nimprovement of scaling behavior of the light quark masses compared to the\nconventional method. We obtain ${\\bar m}_l=3.87(37)$MeV for the averaged up and\ndown quark mass and ${\\bar m}_s=97(9)$MeV for the strange quark mass in the\n${\\barMS}$ scheme at $\\mu=2$GeV.",
        "positive": "The flavour projection of staggered fermions and the quarter-root trick: It is shown that the flavour projection of staggered fermions can be written\nas a projection between the fields on four separate, but parallel, lattices,\nwhere the fields on each are modified forms of the standard staggered fermion\nfield. Because the staggered Dirac operator acts equally on each lattice, it\nrespects this flavour projection. We show that the system can be gauged in the\nusual fashion and that this does not interfere with flavour projection. We also\nconsider the path integral, showing that, prior to flavour projection, it\nevaluates to the same form on each lattice and that this form is equal to that\nused in the quarter-root trick. The flavour projection leaves a path integral\nfor a single flavour of field on each lattice."
    },
    {
        "anchor": "Numerical Methods for the QCD Overlap Operator IV: Hybrid Monte Carlo: The extreme computational costs of calculating the sign of the Wilson matrix\nwithin the overlap operator have so far prevented four dimensional dynamical\noverlap simulations on realistic lattice sizes, because the computational power\nrequired to invert the overlap operator, the time consuming part of the Hybrid\nMonte Carlo algorithm, is too high. In this series of papers we introduced the\noptimal approximation of the sign function and have been developing\npreconditioning and relaxation techniques which reduce the time needed for the\ninversion of the overlap operator by over a factor of four, bringing the\nsimulation of dynamical overlap fermions on medium-size lattices within the\nrange of Teraflop-computers.\n  In this paper we adapt the HMC algorithm to overlap fermions. We approximate\nthe matrix sign function using the Zolotarev rational approximation, treating\nthe smallest eigenvalues of the Wilson operator exactly within the fermionic\nforce. We then derive the fermionic force for the overlap operator, elaborating\non the problem of Dirac delta-function terms from zero crossings of eigenvalues\nof the Wilson operator. The crossing scheme proposed shows energy violations\nwhich are better than O($\\Delta\\tau^2$) and thus are comparable with the\nviolations of the standard leapfrog algorithm over the course of a trajectory.\nWe explicitly prove that our algorithm satisfies reversibility and area\nconservation. Finally, we test our algorithm on small $4^4$, $6^4$, and $8^4$\nlattices at large masses.",
        "positive": "Two-Dimensional $O(3)$ $\u03c3$-Model up to Correlation Length $10^5$: We carry out a high-precision Monte Carlo simulation of the two-dimensional\n$O(3)$-invariant $\\sigma$-model at correlation lengths $\\xi$ up to $\\sim 10^5$.\nOur work employs a new and powerful method for extrapolating finite-volume\nMonte Carlo data to infinite volume, based on finite-size-scaling theory. We\ncompare the extrapolated data to the renormalization-group predictions. The\ndeviation from asymptotic scaling, which is $\\approx 25\\%$ at $\\xi \\sim 10^2$,\ndecreases to $\\approx 4\\%$ at $\\xi \\sim 10^5$."
    },
    {
        "anchor": "Large-q expansion of the energy and magnetization cumulants for the\n  two-dimensional q-state Potts model: We have calculated the large-q expansion for the energy cumulants and the\nmagnetization cumulants at the phase transition point in the two-dimensional\nq-state Potts model to the 21st or 23rd order in $1/\\sqrt{q}$ using the finite\nlattice method. The obtained series allow us to give very precise estimates of\nthe cumulants for $q>4$ on the first order transition point. The result\nconfirms us the correctness of the conjecture by Bhattacharya et al. on the\nasymptotic behavior not only of the energy cumulants but also of the\nmagnetization cumulants for $q \\to 4_+$.",
        "positive": "The Light-Quark Magnetic Moment of the Lambda(1405) Antikaon-Nucleon\n  Molecule: The light-quark sector of the Lambda(1405) baryon is examined in the context\nof the recent discovery of a dominant antikaon-nucleon composition at low quark\nmasses. Further evidence for this interpretation of the Lambda(1405) is\npresented, by calculating the u and d quark contributions to the Lambda(1405)\nmagnetic form factors in lattice QCD. The extent to which these quantities are\nconsistent with the exotic molecular description can then be quantified by\ncomparing the results with the equivalent nucleon form factors. Drawing on a\nrecent extension of the graded-symmetry approach for the flavor-singlet\ncomponents of the Lambda(1405), the separation of the connected and\ndisconnected contributions is performed in both the flavor-octet and singlet\nrepresentations. In both cases, the disconnected loop contributions are found\nto be unexpectedly large. The relationship between the light-quark\ncontributions to the Lambda(1405) magnetic form factor and the connected\ncontributions of the nucleon magnetic form factors is thus confirmed in the\ncase of lattice QCD, establishing compelling evidence for a KN molecular\nstructure of the Lambda(1405) near the physical point."
    },
    {
        "anchor": "Spin Models on Thin Graphs: We discuss the utility of analytical and numerical investigation of spin\nmodels, in particular spin glasses, on ordinary ``thin'' random graphs (in\neffect Feynman diagrams) using methods borrowed from the ``fat'' graphs of two\ndimensional gravity. We highlight the similarity with Bethe lattice\ncalculations and the advantages of the thin graph approach both analytically\nand numerically for investigating mean field results.",
        "positive": "Running coupling from gluon exchange in the Schrodinger functional: I propose a new method to determine the running coupling in a\nSchrodinger-functional setup. The method utilizes the scattering amplitude of\nmassless fermions propagating between the time boundaries. Preliminary tests\nshow the statistical fluctuations of the new observable to be about half those\nof the standard Schrodinger-functional running coupling."
    },
    {
        "anchor": "Novel $|V_{us}|$ Determination Using Inclusive Strange $\u03c4$ Decay and\n  Lattice HVPs: We propose and apply a new approach to determining $|V_{us}|$ using\ndispersion relations with weight functions having poles at Euclidean\n(space-like) momentum which relate strange hadronic $\\tau$ decay distributions\nto hadronic vacuum polarization functions (HVPs) obtained from lattice QCD. We\nshow examples where spectral integral contributions from the region where\nexperimental data have large errors or do not exist are strongly suppressed but\naccurate determinations of the relevant lattice HVP combinations remain\npossible. The resulting $|V_{us}|$ agrees well with determinations from $K$\nphysics and 3-family CKM unitarity. Advantages of this new approach over the\nconventional hadronic $\\tau$ decay determination employing flavor-breaking sum\nrules are also discussed.",
        "positive": "Frontiers of finite temperature lattice QCD: I review a selection of recent finite temperature lattice results of the past\nyears. First I discuss the extension of the equation of state towards high\ntemperatures and fi- nite densities, then I show recent results on the QCD\ntopological susceptibility at high temperatures and highlight its relevance for\ndark matter search."
    },
    {
        "anchor": "Split Grid and Block Lanczos Algorithm for Efficient Eigenpair\n  Generation: The increasing imbalance between the computing capabilities of individual\nnodes and the internode bandwidth makes it highly desirable for any Lattice QCD\nalgorithm to minimize the amount of internode communication. One of the\nrelatively new methods for this is the `Split Grid' or `Split Domain' method,\nwhere data is rearranged within the running of a single binary, so that the\nroutines which requires significant off-node communications such as Dirac\noperators are run on multiple smaller partitions in parallel with a better\nsurface to volume ratio, while other routines are run in one partition.\n  While it is relatively straightforward to utilize Split Grid method for\ninverters, the typical Lanczos algorithm which has one starting vector does not\nrender itself naturally to Split Grid method. In this report we investigate the\nBlock Lanczos algorithm(BL), which allows multiple starting vectors to be\nprocessed in parallel. It is shown that for a moderate number of starting\nvectors, BL achieves convergence comparable to similarly tuned Implicitly\nRestarted Lanczos algorithm (IRL) on 2+1-flavor physical DWF/M\\\"obius ensemble.",
        "positive": "Plasmon mass scale in two dimensional classical nonequilibrium gauge\n  theory: We study the plasmon mass scale in weakly coupled strongly interacting\nnonabelian gauge theory in a two dimensional configuration that mimics the\nboost invariant initial color fields in a heavy ion collision. We numerically\nmeasure the plasmon mass scale using three different methods: a Hard Thermal\nLoop (HTL) expression involving the quasiparticle spectrum constructed from\nCoulomb gauge field correlators, an effective dispersion relation and the\nmeasurement of oscillations between electric and magnetic energies after\nintroducing a spatially uniform perturbation to the electric field. We find\nthat the hard thermal loop expression and the uniform electric field\nmeasurement are in rough agreement. The effective dispersion relation agrees\nwith other methods within a factor of two. We also study the dependence on time\nand occupation number, observing similar trends as in three spatial dimensions,\nwhere a power law dependence sets in after an occupation number dependent\ntransient time. We observe a decrease of the plasmon mass squared as\n$t^{\\frac{-1}{3}}$ at late times."
    },
    {
        "anchor": "Correction to four-loop RG functions in the two-dimensional lattice O(n)\n  $\u03c3$-model: We report the result of our evaluation of the Feynman diagrams appearing in\nthe determination of the four-loop renormalization group functions in the\ntwo-dimensional lattice O($n$) $\\sigma$-model by Caracciolo and Pelissetto. In\nthe list of the integrals used for the determination of those functions, we\nfind that three entries were not correctly evaluated. We give the values for\nthem corrected by us including those for all other integrals which we computed\nwith higher precision. These results are then applied to revise the\ndetermination of the second analytic correction to correlation length $\\xi$ and\nspin susceptibility $\\chi$ by Caracciolo et al. as well as our determination of\nthe mass gap by means of a finite volume technique where we explicitly made use\nof the four-loop $\\beta$-function. In both cases we find sizeable changes in\npredictions. In the meantime there appeared a paper by Alles et al. where they\nrevised one finite integral in the list of our corrected integrals. After\nhaving taken the new revised value into consideration, we found that there are\nno noticeable changes in the perturbative predictions of the present paper\nincluding the final conclusions.",
        "positive": "Investigating the Compton amplitude subtraction function in lattice QCD: Theoretical predictions of the proton--neutron mass difference and\nmeasurements of the proton's charge radius require inputs from the Compton\namplitude subtraction function. Model-dependent and non-relativistic\ncalculations of this subtraction function vary significantly, and hence it\ncontributes sizeable uncertainties to the aforementioned physical quantities.\nWe report on the use of Feynman-Hellmann methods in lattice QCD to calculate\nthe subtraction function from first principles. In particular, our initial\nresults show anomalous high-energy behaviour that is at odds with the\nprediction from the operator product expansion (OPE). Therefore, we investigate\nthe possibility that this unexpected behaviour is due to lattice artifacts, by\nvarying the lattice spacing and volume, and comparing different discretisations\nof the vector current. Finally, we explore a Feynman-Hellmann implementation\nthat is less sensitive to short-distance contributions and show that the\nsubtraction function's anomalous behaviour can be attributed to these\nshort-distance contributions. As such, this work represents the first steps in\nachieving a complete understanding of the Compton amplitude subtraction\nfunction."
    },
    {
        "anchor": "Nonperturbative study of the 't Hooft-Polyakov monopole form factors: The mass and interactions of a quantum 't Hooft-Polyakov monopole are\nmeasured nonperturbatively using correlation functions in lattice Monte Carlo\nsimulations. A method of measuring the form factors for interactions between\nthe monopole and fundamental particles, such as the photon, is demonstrated.\nThese quantities are potentially of experimental relevance in searches for\nmagnetic monopoles.",
        "positive": "The Continuum Limit of Non Compact QED: Since four-fermion operators in strongly coupled $QED$ are nonperturbatively\nrenormalizable, we analyze here the phase diagram and critical behaviour of the\nGauged Nambu-Jona Lasinio model. Our mean field approximation relates the\ncritical exponents along the continuous phase transition line with the mass\ndependence of the chiral condensate in the Coulomb phase of standard noncompact\n$QED$. The numerical results for noncompact $QED$ strongly suggest non mean\nfield exponents along the critical line."
    },
    {
        "anchor": "Discretizing parametrized systems: the magic of Ditt-invariance: Peculiar phenomena appear in the discretization of a system invariant under\nreparametrization. The structure of the continuum limit is markedly different\nfrom the usual one, as in lattice QCD. First, the continuum limit does not\nrequire tuning a parameter in the action to a critical value. Rather, there is\na regime where the system approaches a sort of asymptotic topological\ninvariance (\"Ditt-invariance\"). Second, in this regime the expansion in the\nnumber of discretization points provides a good approximation to the transition\namplitudes. These phenomena are relevant for understanding the continuum limit\nof quantum gravity. I illustrate them here in the context of a simple system.",
        "positive": "$B\\!\\to\\!D^{(*)}\\ell\u03bd$ semileptonic decays in lattice QCD with\n  domain-wall heavy quarks: We calculate the $B \\to D^{(*)} \\ell \\nu$ form factors in 2+1 flavor\nrelativistic lattice QCD by employing the M\\\"obius domain-wall action for all\nquark flavors. Our simulations are carried out at lattice cut-offs $a^{-1} \\sim\n2.5$, 3.6 and 4.5 GeV with the bottom quark masses up to 0.7 $a^{-1}$ to\ncontrol discretization effects. We extrapolate the form factors to the\ncontinuum limit and physical quark masses, and discuss systematic uncertainties\nof the form factors."
    },
    {
        "anchor": "Excited $D$ and $D_{s}$ meson spectroscopy from lattice QCD: We present highly excited spectra of charm-light and charm-strange mesons\nfrom dynamical lattice QCD. Our calculations are performed on anisotropic\n$N_{f} = 2+1$ dynamical ensembles generated by the Hadron Spectrum\nCollaboration. The use of novel techniques and a large basis of interpolating\noperators have allowed us to extract these spectra to a high degree of\nstatistical precision, extract states of high spin and observe candidate hybrid\nmesons. We interpret and discuss our results in light of the current\nexperimental situation.",
        "positive": "Hadronic decay width from finite-volume energy spectrum in lattice QCD: The standard approach to determine the parameters of a resonance is based on\nthe study of the volume dependence of the energy spectrum. In this work we\nstudy a non-linear sigma model coupled to a scalar field in which a resonance\nemerges. Using an analysis method introduced recently, based on the concept of\nprobability distribution, it is possible to determine the mass and the width of\nthe resonance."
    },
    {
        "anchor": "The Landau gauge lattice ghost propagator in stochastic perturbation\n  theory: We present one- and two-loop results for the ghost propagator in Landau gauge\ncalculated in Numerical Stochastic Perturbation Theory (NSPT). The one-loop\nresults are compared with available standard Lattice Perturbation Theory in the\ninfinite-volume limit. We discuss in detail how to perform the different\nnecessary limits in the NSPT approach and discuss a recipe to treat logarithmic\nterms by introducing ``finite-lattice logs''. We find agreement with the\none-loop result from standard Lattice Perturbation Theory and estimate, from\nthe non-logarithmic part of the ghost propagator in two-loop order, the unknown\nconstant contribution to the ghost self-energy in the RI'-MOM scheme in Landau\ngauge. That constant vanishes within our numerical accuracy.",
        "positive": "$K^{+}\\to\u03c0^{+}\u03c0^{0}$ decays at next-to-leading order in the chiral\n  expansion on finite volumes: We present the ingredients for determining $K^{+}\\to\\pi^{+}\\pi^{0}$ matrix\nelements via the combination of lattice QCD and chiral perturbation theory\n($\\chi$PT). By simulating these matrix elements at unphysical kinematics, it is\npossible to determine all the low-energy constants (LECs) for constructing the\nphysical $K^{+}\\to\\pi^{+}\\pi^{0}$ amplitudes at next-to-leading order (NLO) in\nthe chiral expansion. In this work, the one-loop chiral corrections are\ncalculated for arbitrary meson four-momenta, in both $\\chi$PT and quenched\n$\\chi$PT (q$\\chi$PT), and the finite-volume effects are studied."
    },
    {
        "anchor": "$B\\to Kl^+l^-$ decay form factors from three-flavor lattice QCD: We compute the form factors for the $B \\to Kl^+l^-$ semileptonic decay\nprocess in lattice QCD using gauge-field ensembles with 2+1 flavors of sea\nquark, generated by the MILC Collaboration. The ensembles span lattice spacings\nfrom 0.12 to 0.045 fm and have multiple sea-quark masses to help control the\nchiral extrapolation. The asqtad improved staggered action is used for the\nlight valence and sea quarks, and the clover action with the Fermilab\ninterpretation is used for the heavy $b$ quark. We present results for the form\nfactors $f_+(q^2)$, $f_0(q^2)$, and $f_T(q^2)$, where $q^2$ is the momentum\ntransfer, together with a comprehensive examination of systematic errors.\nLattice QCD determines the form factors for a limited range of $q^2$, and we\nuse the model-independent $z$ expansion to cover the whole kinematically\nallowed range. We present our final form-factor results as coefficients of the\n$z$ expansion and the correlations between them, where the errors on the\ncoefficients include statistical and all systematic uncertainties. We use this\ncomplete description of the form factors to test QCD predictions of the form\nfactors at high and low $q^2$. We also compare a Standard-Model calculation of\nthe branching ratio for $B \\to Kl^+l^-$ with experimental data.",
        "positive": "Lattice Studies for hadron spectroscopy and interactions: Recent progresses of lattice QCD studies for hadron spectroscopy and\ninteractions are briefly reviewed. Some emphasis are given on a new proposal\nfor a method, which enable us to calculate potentials between hadrons. As an\nexample of the method, the extraction of nuclear potential in lattice QCD is\ndiscussed in detail."
    },
    {
        "anchor": "Baryon interactions from lattice QCD with physical quark masses --\n  Nuclear forces and $\u039e\u039e$ forces --: We present the latest lattice QCD results for baryon interactions obtained at\nnearly physical quark masses. $N_f = 2+1$ nonperturbatively ${\\cal\nO}(a)$-improved Wilson quark action with stout smearing and Iwasaki gauge\naction are employed on the lattice of $(96a)^4 \\simeq (8.1\\mbox{fm})^4$ with\n$a^{-1} \\simeq 2.3$ GeV, where $m_\\pi \\simeq 146$ MeV and $m_K \\simeq 525$ MeV.\nIn this report, we study the two-nucleon systems and two-$\\Xi$ systems in\n$^1S_0$ channel and $^3S_1$-$^3D_1$ coupled channel, and extract central and\ntensor interactions by the HAL QCD method. We also present the results for the\n$N\\Omega$ interaction in $^5S_2$ channel which is relevant to the $N\\Omega$\npair-momentum correlation in heavy-ion collision experiments.",
        "positive": "Quarks with Twisted Boundary Conditions in the Epsilon Regime: We study the effects of twisted boundary conditions on the quark fields in\nthe epsilon regime of chiral perturbation theory. We consider the\n$SU(2)_L\\times SU(2)_R$ chiral theory with non-degenerate quarks and the\n$SU(3)_L\\times SU(3)_R$ chiral theory with massless up and down quarks and\nmassive strange quarks. The partition function and condensate are derived for\neach theory. Because flavor-neutral Goldstone bosons are unaffected by twisted\nboundary conditions chiral symmetry is still restored in finite volumes. The\ndependence of the condensate on the twisting parameters can be used to extract\nthe pion decay constant from simulations in the epsilon regime. The relative\ncontribution to the partition function from sectors of different topological\ncharge is numerically insensitive to twisted boundary conditions."
    },
    {
        "anchor": "The Abelianicity of Cooled SU(2) Lattice Configurations: We introduce a gauge-invariant measure of the local \"abelianicity\" of any\ngiven lattice configuration in non-abelian lattice gauge theory; it is\nessentially a comparison of the magnitude of field strength commutators to the\nmagnitude of the field strength itself. This measure, in conjunction with the\ncooling technique, is used to probe the SU(2) lattice vacuum for a possible\nlarge-scale abelian background, underlying the local short-range field\nfluctuations. We do, in fact, find a substantial rise in abelianicity over 10\ncooling steps or so, after which the abelianicity tends to drop again.",
        "positive": "A Parallel Computing Method for the Higher Order Tensor Renormalization\n  Group: In this paper, we propose a parallel computing method for the Higher Order\nTensor Renormalization Group (HOTRG) applied to a $d$-dimensional $( d \\geq 2\n)$ simple lattice model. Sequential computation of the HOTRG requires $O (\n\\chi^{4 d - 1} )$ computational cost, where $\\chi$ is bond dimension, in a step\nto contract indices of tensors. When we simply distribute elements of a local\ntensor to each process in parallel computing of the HOTRG, frequent\ncommunication between processes occurs. The simplest way to avoid such\ncommunication is to hold all the tensor elements in each process, however, it\nrequires $O ( \\chi^{2d} )$ memory space. In the presented method, placement of\na local tensor element to more than one process is accepted and sufficient\nlocal tensor elements are distributed to each process to avoid communication\nbetween processes during considering computation step. For the bottleneck part\nof computational cost, such distribution is achieved by distributing elements\nof two local tensors to $\\chi^2$ processes according to one of the indices of\neach local tensor which are not contracted during considering computation. In\nthe case of $d \\geq 3$, computational cost in each process is reduced to $O (\n\\chi^{4 d - 3} )$ and memory space requirement in each process is kept to be $O\n( \\chi^{2d - 1} )$."
    },
    {
        "anchor": "Meson decay constants from Nf=2 clover fermions: We present recent results for meson decay constants calculated on\nconfigurations with two flavours of O(a)-improved Wilson fermions.\nNon-perturbative renormalisation is applied and quark mass dependencies as well\nas finite volume and discretisation effects are investigated. In this work we\nalso present a computation of the coupling of the light vector mesons to the\ntensor current using dynamical fermions.",
        "positive": "Dual simulation of finite density lattice QED at large mass: We discuss a mapping of lattice QED with two flavors and a chemical potential\nto dual variables, which are surfaces for the gauge fields and loops for the\nfermions. The gauge fields are completely dualized and the corresponding dual\nvariables are integer valued plaquette occupation numbers with constraints that\nlead to a structure of surfaces that are either closed or bounded by fermion\nloops. The fermion loops are obtained from a resummed hopping expansion (large\nmass expansion) of the determinant of the Wilson-Dirac operator. The loops can\ncome with both positive and negative signs. We identify a sub-class of loops,\nwhich we refer to as quasi-planar loops, where the total sign is positive. For\nthis sub-class a dual Monte Carlo simulation is possible and we discuss its\nimplementation and some results. In particular we address condensation\nphenomena at finite chemical potential."
    },
    {
        "anchor": "New Ways to Determine Low-Energy Constants with Wilson Fermions: We show how the leading physical and Wilson low-energy constants associated\nwith Wilson fermions in lattice gauge theory can be determined individually by\nusing spectral information of the Wilson Dirac operator with fixed index at\nfinite volume. The methods are demonstrated in simulations with leading-order\nimproved Wilson fermions. In addition to the expected suppression of the\nleading term in Wilson chiral perturbation theory we observe a substantial\nreduction also of the higher-order Wilson low-energy constants.",
        "positive": "Dynamically generated electric charge distributions in Abelian projected\n  SU(2) lattice gauge theories: We show in the maximal Abelian gauge the dynamical electric charge density\ngenerated by the coset fields, gauge fixing and ghosts shows antiscreening as\nin the case of the non-Abelian charge. We verify that with the completion of\nthe ghost term all contributions to flux are accounted for in an exact lattice\nEhrenfest relation."
    },
    {
        "anchor": "Charmonia from Lattice QCD: Recent lattice QCD results on charmonium properties are reviewed. I comment\non molecules and hybrid states as well as on future studies of states near\nstrong decay thresholds.",
        "positive": "End-to-end distribution function for dilute polymers: We study the end-to-end distribution function for dilute polymers. We present\na computation to order $O(\\epsilon^2)$, $\\epsilon = 4 - d$, and discuss in\ndetail its asymptotic behaviour for small and large distances. The theoretical\npredictions are compared with Monte Carlo results, finding good agreement."
    },
    {
        "anchor": "Dynamical simulations with HYP-link Wilson fermions: We present results from simulations of two dynamical flavors of improved\nWilson fermions with nHYP smeared gauge links. We demonstrate that the\nsimulation is stable at a pseudo-scalar mass of 360MeV, a 2.1fm box and a\nlattice spacing of 0.13fm.",
        "positive": "Long-distance behavior of $q\\bar{q}$ color dependent potentials at\n  finite temperature: SU(3) heavy quark potentials at finite temperature are studied with quenched\nlattice QCD using the stochastic gauge-fixing method. In addition to the\nstandard color average channel, we investigate $q\\bar{q}$ potentials in singlet\nand octet channels. % We obtain clear signals in all cases. The singlet\n$q\\bar{q}$ channel yields an attractive force, while the octet $q\\bar{q}$\npotential is repulsive; the corresponding color average channel also results in\nan attractive force. %As the temperature increases, these forces are weakened\nand As the temperature increases, these forces become weak and their variations\nare very small; at $T/T_c=1.8-5.6$, % the singlet attractive force is not so\nweakened even for long distances. the singlet attractive force survives over $R\n\\sim 1/T$. The singlet and octet potentials calculated with this algorithm have\na small gauge dependence when the gauge parameter $\\alpha$ is changed from 0.6\nto 1.3."
    },
    {
        "anchor": "Geometrical Volume Effects in the Computation of the Slope of the\n  Isgur-Wise Function: We use a method recently suggested for evaluating the slope of the Isgur-Wise\nfunction, at the zero-recoil point, on the lattice. The computations are\nperformed in the quenched approximation to lattice QCD, on a $24^3 \\times 48$\nlattice at $\\beta=6.2$, using an $O(a)$-improved action for the fermions. We\nhave found unexpectedly large finite-volume effects in such a calculation.\nThese volume corrections turned out to be purely geometrical and independent of\nthe dynamics of the system. After the study of these effects on a smaller\nvolume and for different quark masses, we give approximate expressions that\naccount for them. Using these approximations we find $\\xi^\\prime(1)=-1.7 \\pm\n0.2$ and $\\xi^\\prime(1)=-1.4 +0.2-0.1$ for the slope of the Isgur-Wise\nfunction, for two mesons composed of a heavy quark slightly heavier and\nlighter, respectively, than the charm quark, and in both cases, a light\nantiquark whose mass is about that of the strange quark.",
        "positive": "Diquark condensation in dense SU(2) matter: We report on a lattice study of two-color QCD with adjoint staggered fermions\nat high density. We find that the model has no early onset and we report on\nresults for diquark condensation, from simulations with and without a diquark\nsource term."
    },
    {
        "anchor": "Perturbative renormalisation of quark bilinear operators for overlap\n  fermions with and without stout links and improved gauge action: We calculate lattice renormalisation constants of local and one-link quark\noperators for overlap fermions and improved gauge actions in one-loop\nperturbation theory. For the local operators we stout smear the SU(3) links in\nthe fermionic action. Using the popular tadpole improved L\\\"uscher-Weisz\nactions at $\\beta=8.45$ and $\\beta=8.0$ we present numerical values for the Z\nfactors in the $\\bar{MS}$ scheme (partly as function of the stout smearing\nstrength). We compare various levels of mean field (tadpole) improvement which\nhave been applied to our results.",
        "positive": "Understanding the Aoki phase: The vacuum structure of QCD with two degenerated flavours of Wilson fermions\nis discussed by means of the p.d.f. (probability distribution function)\nformalism. Under certain assumptions, either new phases related to Aoki's\nappear, characterized by a non-vanishing expectation value of the condensate\n$i\\bar\\psi_u\\gamma_5\\psi_u + i\\bar\\psi_d\\gamma_5\\psi_d$, enriching the standard\npicture of the QCD vacuum structure with Wilson fermions; or the eigenvalues of\nthe Dirac-Wilson operator must comply with a non-trivial, infinite set of sum\nrules, enforcing the currently accepted structure of the Aoki vacuum.\n  The same scenario is analyzed using the Ginsparg-Wilson regularization. In\nthis case, the absence of any parity and/or flavour breaking phase is proved\nfor a non-zero value of the fermion mass."
    },
    {
        "anchor": "Complex Langevin simulation for QCD-like models: We first test the Complex Langevin method (CLE) on various simple models. We\nthen introduce the method of Gauge Cooling to control the dynamics of the\nprocess and ensure thin distributions in the imaginary direction. We finally\napply CLE with gauge cooling to a QCD-related lattice model (HQCD) and compare\nthe results by CLE and by a refined Reweighting method (rRW). Very good\nagreement is found in all regions of physical interest.",
        "positive": "On the structure of QCD confining string: This paper had been withdrawn because the prime reported effect had not been\nconfirmed in further investigations (see arXiv:0812.4488 [hep-lat])."
    },
    {
        "anchor": "Spatial and Temporal Hadron Correlators below and above the Chiral Phase\n  Transition: Hadronic correlation functions at finite temperature in QCD, with four\nflavours of dynamical quarks, have been analyzed both above and below the\nchiral symmetry restoration temperature. We have used both point and extended\nsources for spatial as well as temporal correlators. The effect of periodic\ntemporal boundary conditions for the valence quarks on the spatial meson\ncorrelators has also been investigated. All our results are consistent with the\nexistence of individual quarks at high temperatures. A measurement of the\nresidual interaction between the quarks is presented.",
        "positive": "The equation of state with non-equilibrium methods: Jarzynski's equality provides an elegant and powerful tool to directly\ncompute differences in free energy in Monte Carlo simulations and it can be\nreadily extended to lattice gauge theories to compute a large set of physically\ninteresting observables. In this talk we present a novel technique to determine\nthe thermodynamics of strongly-interacting matter based on this relation, which\nallows for a direct and efficient determination of the pressure using\nout-of-equilibrium Monte Carlo simulations on the lattice. We present results\nfor the equation of state of the $\\mathrm{SU}(3)$ Yang-Mills theory in the\nconfined and deconfined phases. Finally, we briefly discuss the generalization\nof this method for theories with fermions, with particular focus on the\nequation of state of QCD."
    },
    {
        "anchor": "Twisted Superspace on a Lattice: We propose a new formulation which realizes exact twisted supersymmetry for\nall the supercharges on a lattice by twisted superspace formalism. We show\nexplicit examples of N=2 twisted supersymmetry invariant BF and Wess-Zumino\nmodels in two dimensions. We introduce mild lattice noncommutativity to\npreserve Leibniz rule on the lattice. The formulation is based on the twisted\nsuperspace formalism for N=D=2 supersymmetry which was proposed recently. From\nthe consistency condition of the noncommutativity of superspace, we find an\nunexpected three-dimensional lattice structure which may reduce into two\ndimensional lattice where the superspace describes semilocally scattered\nfermions and bosons within a double size square lattice.",
        "positive": "LQCD: Flavor Physics and Spectroscopy: I review highlights of recent results in quark-flavor physics and heavy-quark\nspectroscopy from lattice QCD, with emphasis on $B$-meson decays and excited\nand exotic charmonium states."
    },
    {
        "anchor": "A solution of the Gross-Witten matrix model by nonlinear random\n  processes: We illustrate the stochastic method for solving the Schwinger-Dyson equations\nin large-N quantum field theories described in ArXiv:1009.4033 on the example\nof the Gross-Witten unitary matrix model. In the strong-coupling limit, this\nmethod can be applied directly, while in the weak-coupling limit we change the\nvariables from compact to noncompact ones in order to cast the Schwinger-Dyson\nequations in the stochastic form. This leads to a new action with an infinite\nnumber of higher-order interaction terms. Nevertheless, such an action can be\nefficiently handled. This suggests the way to apply the method of\nArXiv:1009.4033 to field theories with U(N) field variables as well as to\neffective field theories in the large-N limit.",
        "positive": "Thermal QCD with external imaginary electric fields on the lattice: We study QCD at finite temperature in the presence of imaginary electric\nfields. In particular, we determine the electric susceptibility, the leading\ncoefficient in the expansion of the QCD pressure in the imaginary field. Unlike\nfor magnetic fields, at nonzero temperature this coefficient requires a\nnon-trivial separation of genuine electric field-related effects and spurious\neffects related to the chemical potential, which becomes an unphysical gauge\nparameter in this setting. Our results are based on lattice simulations with\nstout improved dynamical staggered quarks at physical quark masses."
    },
    {
        "anchor": "The large-N expansion of unitary-matrix models: The general features of the 1/N expansion in statistical mechanics and\nquantum field theory are briefly reviewed both from the theoretical and from\nthe phenomenological point of view as an introduction to a more detailed\nanalysis of the large-N properties of spin and gauge models possessing the\nsymmetry group $SU(N) \\times SU(N)$.\n  An extensive discussion of the known properties of the single-link integral\n(equivalent to YM_2 and one-dimensional chiral models) includes finite-$N$\nresults, the external field solution, properties of the determinant, and the\ndouble scaling limit.\n  Two major classes of solvable generalizations are introduced: one-dimensional\nclosed chiral chains and models defined on a $d-1$ dimensional simplex. In both\ncases large-N solutions are presented with emphasis on their double scaling\nproperties.\n  The available techniques and results concerning unitary-matrix models that\ncorrespond to asymptotically free quantum field theories (two-dimensional\nchiral models and four-dimensional QCD) are discussed, including\nstrong-coupling methods, reduced formulations, and the Monte Carlo approach.",
        "positive": "One flavour adjoint QCD with overlap fermions: The infrared effective theory of adjoint QCD with one Dirac flavour is still\nunder debate. The theory could be confining, conformal, or with a massless\nfermion in the infrared. The study of chiral symmetry seems to be important to\nanswer this question. While previous investigations have considered Wilson\nfermions, we present here the first results for this theory based on overlap\nfermions to avoid explicit chiral symmetry breaking. These indicate spontaneous\nchiral symmetry breaking by the formation of a fermion condensate. We have also\ninvestigated the running coupling of the theory, which indicates no infrared\nconformality in the energy region we have explored."
    },
    {
        "anchor": "Lattice Fermions without Doublers: By placing fermions only on the even sites of a lattice, one may halve the\nmomentum spectrum and construct a theory without doublers. The interaction is\nnonlocal. The fermion propagator is not a sparse matrix, but because the\nunwanted fermionic states are absent from the formalism, it is 256 times\nsmaller than the usual propagator.",
        "positive": "Construction of lattice M\u00f6bius domain wall fermions in the\n  Schr\u00f6dinger functional scheme: In this paper we construct the M\\\"obius domain wall fermions (MDWF) in the\nSchr\\\"odinger functional (SF) scheme for the SU(3) gauge theory by adding a\nboundary operator at the temporal boundary of the SF scheme setup and\ninvestigate the property using the perturbation theory. The MDWFs we\ninvestigated include the optimal type domain wall, the overlap, the truncated\ndomain wall, and the truncated overlap fermions. We observe the universality of\nthe spectrum of the effective four-dimensional operator at the tree-level. The\nfermionic contribution to the universal one-loop beta function is reproduced\nfor the MDWFs with a sufficiently large fifth dimensional extent."
    },
    {
        "anchor": "Exploring autocorrelations in two-flavour Wilson Lattice QCD using\n  DD-HMC algorithm: We perform an extensive study of autocorrelation of several observables in\nlattice QCD with two degenerate flavours of naive Wilson fermions and\nunimproved Wilson gauge action using DD-HMC algorithm. We show that (1) at a\ngiven lattice spacing, autocorrelation of topological susceptibility decreases\nwith decreasing quark mass and autocorrelations of plaquette and Wilson loop do\nnot increase with decreasing quark mass, (2) autocorrelation of topological\nsusceptibility substantially increases with decreasing lattice spacing but\nautocorrelation of topological charge density correlator shows only mild\nincrease and (3) increasing the size and the smearing level increase the\nautocorrelation of Wilson loop.",
        "positive": "Universality and massive excitations in 3d 3-state Potts model: The mass spectrum of the 3d 3-state Potts model is considered in the broken\nphase (a) near the second order Ising critical point in the\ntemperature-magnetic field plane and (b) near the weakly first order transition\npoint at zero magnetic field. In the case (a), the mass spectrum is compared\nwith the prediction from universality of mass ratios in the 3d Ising class; in\nthe case (b) a mass ratio is determined to be compared with the corresponding\none in the spectrum of screening masses of the (3+1)d SU(3) pure gauge theory\nat finite temperature in the deconfined phase near the transition."
    },
    {
        "anchor": "Dual simulation of a Polyakov loop model at finite baryon density: phase\n  diagram and local observables: Many Polyakov loop models can be written in a dual formulation which is free\nof sign problem even when a non-vanishing baryon chemical potential is\nintroduced in the action. Here, results of numerical simulations of a dual\nrepresentation of one such effective Polyakov loop model at finite baryon\ndensity are presented. We compute various local observables such as energy\ndensity, baryon density, quark condensate and describe in details the phase\ndiagram of the model. The regions of the first order phase transition and the\ncrossover, as well as the line of the second order phase transition, are\nestablished. We also compute several correlation functions of the Polyakov\nloops.",
        "positive": "Symanzik Improvement with Dynamical Charm: A 3+1 Scheme for Wilson\n  Quarks: We discuss the problem of lattice artefacts in QCD simulations enhanced by\nthe introduction of dynamical charmed quarks. In particular, we advocate the\nuse of a massive renormalization scheme with a close to realistic charm mass.\nTo maintain O(a) improvement for Wilson type fermions in this case we define a\nfinite size scheme and carry out a nonperturbative estimation of the clover\ncoefficient $c_\\mathrm{sw}$. It is summarized in a fit formula\n$c_\\mathrm{sw}(g_0^2)$ that defines an improved action suitable for future\ndynamical charm simulations."
    },
    {
        "anchor": "Finite-Volume Electromagnetic Corrections to the Masses of Mesons,\n  Baryons and Nuclei: Now that Lattice QCD calculations are beginning to include QED, it is\nimportant to better understand how hadronic properties are modified by\nfinite-volume QED effects. They are known to exhibit power-law scaling with\nvolume, in contrast to the exponential behavior of finite-volume strong\ninteraction effects. We use non-relativistic effective field theories\ndescribing the low-momentum behavior of hadrons to determine the finite-volume\nQED corrections to the masses of mesons, baryons and nuclei out to O(1/L^4) in\na volume expansion, where L is the spatial extent of the cubic volume. This\ngeneralizes the previously determined expansion for mesons, and extends it by\ntwo orders in 1/L to include contributions from the charge radius, magnetic\nmoment and polarizabilities of the hadron. We make an observation about direct\ncalculations of the muon g-2 in a finite volume.",
        "positive": "Second Moments of Nucleon Unpolarized, Polarized, and Transversity\n  Parton Distribution Functions from Lattice QCD at the Physical Point: The second Mellin moments of the nucleon's unpolarized, polarized, and\ntransversity parton distribution functions (PDFs) are computed. Two lattice QCD\nensembles at the physical pion mass are used: these were generated using a\ntree-level Symanzik-improved gauge action and 2+1 flavour tree-level improved\nWilson Clover fermions coupling via 2-level HEX-smearing. The moments are\nextracted from forward matrix elements of local leading twist operators. We\ndetermine renomalization factors in RI-(S)MOM and match to $\\bar{\\mathrm{MS}}$\nat scale $2\\,\\mathrm{GeV}$. Our findings show that operators that exhibit\nvanishing kinematics at zero momentum can have significantly reduced\nexcited-state contamination. The resulting polarized moment is used to quantify\nthe longitudinal contribution to the quark spin-orbit correlation. All our\nresults agree within two sigma with previous lattice results."
    },
    {
        "anchor": "Domain Wall Fermions with Exact Chiral Symmetry: We show how the standard domain wall action can be simply modified to allow\narbitrarily exact chiral symmetry at finite fifth dimensional extent. We note\nthat the method can be used for both quenched and dynamical calculations. We\ntest the method using smooth and thermalized gauge field configurations. We\nalso make comparisons of the performance (cost) of the domain wall operator for\nspectroscopy compared to other methods such as the overlap-Dirac operator and\nfind both methods are comparable in cost.",
        "positive": "ChPT meets lattice: finite volume and partial quenching for masses,\n  decay constants and VEVs at NNLO: We discuss finite volume effects and partial quenching for Chiral\nPerturbation Theory in the mesonic sector. The effects are computed in terms of\nanalytical expressions for masses, decay constants and vacuum expectation\nvalues (VEVs) to two-loop order. Numerical examples are presented for a number\nof interesting and relevant cases. All numerical programs are publically\navailable, the prospects of a combination of these studies with lattice gauge\ntheory computations are discussed briefly."
    },
    {
        "anchor": "High-Precision Charm-Quark Mass and QCD Coupling from Current-Current\n  Correlators in Lattice and Continuum QCD: We use lattice QCD simulations, with MILC gluon configurations and HISQ\nc-quark propagators, to make very precise determinations of moments of\ncharm-quark pseudoscalar, vector and axial-vector correlators. These moments\nare combined with new four-loop results from continuum perturbation theory to\nobtain several new determinations of the MSbar mass of the charm quark and of\nthe MSbar coupling. We find m_c(3GeV)=0.986(10)GeV, or, equivalently,\nm_c(m_c)=1.268(9)GeV, both for n_f=4 flavors; and\nalpha_msb(3GeV,n_f=4)=0.251(6), or, equivalently,\nalpha_\\msb(M_Z,n_f=5)=0.1174(12). The new mass agrees well with results from\ncontinuum analyses of the vector correlator using experimental data for e+e-\nannihilation (instead of using lattice QCD simulations). These lattice and\ncontinuum results are the most accurate determinations to date of this mass.\nOurs is also one of the most accurate determinations of the QCD coupling by any\nmethod.",
        "positive": "Proton generalized parton distributions from lattice QCD: Momentum and spatial distributions of quarks and gluons inside hadrons are\ntypically encoded in the so-called generalized parton distributions (GPDs).\nGPDs are multi-dimensional quantities that are very challenging to extract,\nboth experimentally and within lattice QCD. We present the first lattice\nresults on the $x$-dependence of isovector unpolarized, helicity and\ntransversity GPDs of the proton, obtained from lattice QCD using an ensemble of\n$N_f=2+1+1$ maximally twisted mass fermions, with pion mass $M_\\pi=260$ MeV and\nlattice spacing $a\\simeq 0.093$ fm. Our calculations use the quasi-distribution\nformalism and the final distributions are presented in the MS-bar scheme at a\nrenormalization scale of 2 GeV."
    },
    {
        "anchor": "The Absence of Ultralocal Ginsparg-Wilson Fermions: It was shown recently by I. Horvath that lattice fermions obeying the\nstandard form of the Ginsparg-Wilson relation cannot be ultralocal. However,\nthere are more general forms of the Ginsparg-Wilson relation, which also\nguarantee the physical properties related to chirality, but which are not\ncovered by Horvath's consideration. Here we present a proof which applies to\nall Ginsparg-Wilson fermions, demonstrating that they can only be local in the\nsense of an exponential decay of their couplings, but not ultralocal.",
        "positive": "A lattice Dirac operator for QCD with light dynamical quarks: In QCD chiral symmetry is explicitly broken by quark masses, the effect of\nwhich can be described reliably by chiral perturbation theory. Effects of\nexplicit chiral symmetry breaking by the lattice regularisation of the Dirac\noperator, typically parametrised by the residual mass, should be negligible for\nalmost all observables if the residual mass of the Dirac operator is much\nsmaller than the quark mass. However, maintaining a small residual mass becomes\nincreasingly expensive as the quark mass decreases towards the physical value\nand the continuum limit is approached. We investigate the feasibility of using\na new approximately chiral Dirac operator with a small residual mass as an\nalternative to overlap and domain wall fermions for lattice simulations. Our\nDirac operator is constructed from a Zolotarev rational approximation for the\nmatrix sign function that is optimal for bulk modes of the Hermitian kernel\nDirac operator but not for the low-lying parts of its spectrum. We test our\noperator on various 32^3\\times64 lattices, comparing the residual mass and the\nperformance of the Hybrid Monte Carlo algorithm at a similar lattice spacing\nand pion mass with a hyperbolic tangent operator as used by domain wall\nfermions. We find that our approximations have a significantly smaller residual\nmass than domain wall fermions at a similar computational cost, and still admit\ntopological charge change."
    },
    {
        "anchor": "Nucleon distribution amplitudes and proton decay matrix elements on the\n  lattice: Baryon distribution amplitudes (DAs) are crucial for the theory of hard\nexclusive reactions. We present a calculation of the first few moments of the\nleading-twist nucleon DA within lattice QCD. In addition we deal with the\nnormalization of the next-to-leading (twist-four) DAs. The matrix elements\ndetermining the latter quantities are also responsible for proton decay in\nGrand Unified Theories. Our lattice evaluation makes use of gauge field\nconfigurations generated with two flavors of clover fermions. The relevant\noperators are renormalized nonperturbatively with the final results given in\nthe MSbar scheme. We find that the deviation of the leading-twist nucleon DA\nfrom its asymptotic form is less pronounced than sometimes claimed in the\nliterature.",
        "positive": "SU(2) Gluodynamics and HP1 sigma-model embedding: Scaling, Topology and\n  Confinement: We investigate recently proposed HP1 sigma-model embedding method aimed to\nstudy the topology of SU(2) gauge fields. The HP1 based topological charge is\nshown to be fairly compatible with various known definitions. We study the\ncorresponding topological susceptibility and estimate its value in the\ncontinuum limit. The geometrical clarity of HP1 approach allows to investigate\nnon-perturbative aspects of SU(2) gauge theory on qualitatively new level. In\nparticular, we obtain numerically precise estimation of gluon condensate and\nits leading quadratic correction. Furthermore, we present clear evidences that\nthe string tension is to be associated with global (percolating) regions of\nsign-coherent topological charge. As a byproduct of our analysis we estimate\nthe continuum value of quenched chiral condensate and the dimensionality of\nregions, which localize the lowest eigenmodes of overlap Dirac operator."
    },
    {
        "anchor": "Form factors for semi-leptonic $B$ decays: Semi-leptonic $B$ decays provide promising channels to test the Standard\nModel, search for signs of new physics, or determine fundamental parameters\nlike CKM matrix elements. We present an update on our calculation of short\ndistance contributions to GIM suppressed rare $B$ decays focusing in particular\non $B_s\\to \\phi \\ell^+ \\ell^-$ decays. Furthermore we show first results for\nour calculation of $B_{(s)}\\to D_{(s)}^{(*)}\\ell\\nu$ semi-leptonic decays\ninvolving $b\\to c$ transitions. Our calculations are based on RBC-UKQCD's 2+1\nflavor domain-wall fermion and Iwasaki gauge field configurations featuring\nthree lattice spacings in the range $1.73$ GeV $\\le a^{-1} \\le 2.77$ GeV and\npion masses down to the physical value. We calculate the form factors by\nsimulating $b$-quarks using the relativistic heavy quark action, create light\n$u/d$ and $s$ quarks with standard domain-wall kernel, and use optimised\nM\\\"obius domain-wall fermions for charm quarks.",
        "positive": "Progress toward the chiral regime in lattice QCD calculations of the\n  neutron electric polarizability: The static electric polarizability of the neutron is evaluated using\ndomain-wall valence quarks on a MILC asqtad sea quark ensemble corresponding to\na pion mass of m_pi = 357 MeV. Both connected as well as disconnected\ncontributions are included. The result is quantitatively compatible with the\nexpectation from chiral effective theory."
    },
    {
        "anchor": "Field theoretic study of a cold Fermi gas in the unitary limit: Trapped and cooled gases of alkali atoms can be manipulated to exhibit a\nvariety of interesting phenomena. For example, dilute gases of fermionic atoms,\nin 2 hyperfine states, can be cooled to temperatures where they become\nsuperfluid. An external field can be applied to tune the scattering length a.\nWhen |a| exceeds the interparticle spacing, nonperturbative tools are needed to\nstudy the system theoretically. The unitary limit, |a|\\to\\infty, is\nparticularly interesting due to its universality and symmetry. Lattice field\ntheory and effective field theory can be used to systematically calculate\nproperties of this system. Results are presented for the finite temperature\nphase transition and for behavior near zero temperature.",
        "positive": "Gluon Parton Distribution of the Nucleon from 2+1+1-Flavor Lattice QCD\n  in the Physical-Continuum Limit: We present the first physical-continuum limit $x$-dependent nucleon gluon\ndistribution from lattice QCD using the pseudo-PDF approach, on lattice\nensembles with $2+1+1$ flavors of highly improved staggered quarks (HISQ),\ngenerated by MILC Collaboration. We use clover fermions for the valence action\non three lattice spacings $a \\approx 0.9$, 0.12 and 0.15~fm and three pion\nmasses $M_\\pi \\approx 220$, 310 and 690~MeV, with nucleon two-point\nmeasurements numbering up to $O(10^6)$ and nucleon boost momenta up to 3~GeV.\nWe study the lattice-spacing and pion-mass dependence of the reduced pseudo-ITD\nmatrix elements obtained from the lattice calculation, then extrapolate them to\nthe continuum-physical limit before extracting $xg(x)/\\langle x \\rangle_g$. We\nuse the gluon momentum fraction $\\langle x \\rangle_g$ calculated from the same\nensembles to determine the nucleon gluon unpolarized PDF $xg(x)$ for the first\ntime entirely through lattice-QCD simulation. We compare our results with\nprevious single-ensemble lattice calculations, as well as selected global fits."
    },
    {
        "anchor": "Fixed point action and topological charge for SU(2) gauge theory: We present a theoretically consistent definition of the topological charge\noperator based on renormalization group arguments. Results of the\n  measurement of the topological susceptibility at zero and finite temperature\nfor SU(2) gauge theory are presented.",
        "positive": "Inherently Global Nature of Topological Charge Fluctuations in QCD: We have recently presented evidence that in configurations dominating the\nregularized pure-glue QCD path integral, the topological charge density\nconstructed from overlap Dirac operator organizes into an ordered space-time\nstructure. It was pointed out that, among other properties, this structure\nexhibits two important features: it is low-dimensional and geometrically\nglobal, i.e. consisting of connected sign-coherent regions with local\ndimensions 1<= d < 4, and spreading over arbitrarily large space--time\ndistances. Here we show that the space-time structure that is responsible for\nthe origin of topological susceptibility indeed exhibits global behavior. In\nparticular, we show numerically that topological fluctuations are not saturated\nby localized concentrations of most intense topological charge density. To the\ncontrary, the susceptibility saturates only after the space-time regions with\nmost intense fields are included, such that geometrically global structure is\nalready formed. We demonstrate this result both at the fundamental level (full\ntopological density) and at low energy (effective density). The drastic\nmismatch between the point of fluctuation saturation (~ 50% of space-time at\nlow energy) and that of global structure formation (<4% of space-time at low\nenergy) indicates that the ordered space-time structure in topological charge\nis inherently global and that topological charge fluctuations in QCD cannot be\nunderstood in terms of individual localized pieces. Description in terms of\nglobal brane-like objects should be sought instead."
    },
    {
        "anchor": "The fermion determinant and the chiral gauge theory on a lattice: Considering as an example a simple lattice ansatz for the chiral fermion\ndeterminant, we demonstrate that even very mild violation of gauge invariance\nby the determinant at finite lattice spacing leads to the need for another\nscale in the full gauge theory. This new scale is much grater than the lattice\nspacing and is associated with the gauge variables.",
        "positive": "Lattice QCD Study for Confinement in Hadrons: We study three subjects on quark confinement in hadrons in SU(3)$_{\\rm c}$\nlattice QCD. From the accurate lattice calculation for more than 300 different\npatterns of three-quark (3Q) systems, we find that the static 3Q potential is\nwell described by Y-Ansatz, i.e., the Coulomb plus Y-type linear potential. We\nalso study the multi-quark (4Q, 5Q) potentials in lattice QCD, and find that\nthey are well described by the one-gluon-exchange (OGE) Coulomb plus\nstring-theoretical linear potential, which supports the {\\it infrared string\npicture} even for the multi-quarks. The second subject is a lattice-QCD\ndetermination of the relevant gluonic momentum component for confinement. The\nstring tension (confining force) is found to be almost unchanged even after\ncutting off the high-momentum gluon component above 1.5GeV in the Landau gauge.\nIn fact, {\\it quark confinement originates from the low-momentum gluon below\nabout 1.5GeV.} Finally, we consider a possible gauge of QCD for the quark\npotential model, by investigating \"instantaneous inter-quark potential\" in\ngeneralized Landau gauge, which describes a continuous change from the Landau\ngauge to the Coulomb gauge."
    },
    {
        "anchor": "Hadron Scattering Lengths in Lattice QCD: Lattice QCD calculation of s-wave hadron scattering lengths in the channels\n\\pi-\\pi, \\pi-N, K-N, {\\bar K}-N and N-N is carried out in the quenched QCD at\n$\\beta=6/g^2=5.7$. A variant of the method of wall sourceis developed for this\npurpose, which reduces the computer time by a factor L^3 on an L^3xT lattice\ncompared to the conventional point source method and avoids the Fierz mixing\nproblem. A version of the method in which gauge configurations are not fixed to\nany gauge can be extended to calculate disconnected quark loop con- tributions\nin hadron two- and three-point functions. An analytical estimate of statistical\nerrors for this method is worked out, and the magnitude of errors without and\nwith gauge fixing is compared for the case of \\pi-\\pi four-point functions\ncalculated with the KS quark action. For \\pi-\\pi scattering both I=0 and 2\nscattering lengths are evaluated using the KS and Wilson quark actions on a\n12^3x20 lattice. For the same size of lattice, \\pi-N, K-N and {\\bar K}-N\nscattering lenghts are calculated with the Wilson quark action. For the \\pi-\\pi\nand \\pi-N cases simulation results are consistent with the predictions of\ncurrent algebra and PCAC within one to two standard deviations up to quite\nheavy quark masses corresponding to $m_\\pi/m_\\rho\\approx 0.74$, while for the\nK-N and {\\bar K}-N cases the agreement is within a factor of two. For N-N scat-\ntering simulations with the Wilson action on a 20^4 lattice with heavy quarks\nwith $m_\\pi/m_\\rho\\approx 0.74-0.95$, where the deuteron is expected to become\nunbound from a phenomenological study with one-boson exchange potentials, show\nthat the nucleon-nucleon force is attractive for both spin triplet and singlet\nchannels, and that the scattering lengths are substantially larger compared to\nthose for the \\pi-\\pi and \\pi-N cases even for such heavy quarks.",
        "positive": "Strings with Extrinsic Curvature: An Analysis of the Crossover Regime: We present the results of a set of Monte Carlo simulations of Dynamically\nTriangulated Random Surfaces embedded in three dimensions with an extrinsic\ncurvature dependent action. We analyze several observables in the crossover\nregime and discuss whether or not our observations are indicative of the\npresence of a phase transition."
    },
    {
        "anchor": "Center vortices of Yang-Mills theory at finite temperatures: Recent lattice calculations performed at zero temperature and in the maximal\ncenter gauge indicate that quark confinement can be understood in this gauge as\ndue to fluctuations in the number of magnetic vortices piercing a given Wilson\nloop. This development has led to a revival of the vortex condensation theory\nof confinement. For a SU(2) gauge group, we show that also at finite\ntemperatures, center vortices are the relevant collective infrared degrees of\nfreedom determining the long-range static quark potential; in particular, their\ndynamics reflect the transition to the deconfining phase.",
        "positive": "Lattice Monte Carlo Data versus Perturbation Theory: Differences between lattice Monte Carlo data and perturbation theory (for\nexample the lack of asymptotic scaling) are usually associated with the `bad'\nbehaviour of the bare lattice coupling g_0 due to the effects of large (and\nunknown) higher order terms in g_0. In this philosophy a new, renormalised\ncoupling g' is defined with the aim of making the higher order coefficients of\nthe perturbative series in g' as small as possible.\n  In this paper an alternative scenario is discussed where lattice artifacts\nare proposed as the cause of the disagreement between Monte Carlo data and the\ng_0-perturbative series. We find that with the addition of a lattice artifact\nterm, the usual asymptotic scaling expression in g_0 is in excellent agreement\nwith Monte Carlo data. Lattice data studied includes the string tension, the\nhadronic scale r_0, the discrete beta function, M_rho, f_pi and the 1P-1S\nsplitting in charmonium."
    },
    {
        "anchor": "Toward gauge independent study of confinement in SU(3) Yang-Mills theory: Dual superconductivity is believed to be a promising mechanism for quark\nconfinement and has been investigated on a lattice effectively by a particular\ngauge called the maximal Abelian (MA) gauge. We propose a new formulation of\nSU(3) Yang-Mills theory on a lattice based on a non-linear change of variables\nwhere the new field variables are expected to reduce to those of the\nCho-Faddeev-Niemi- Shabanov decomposition in the continuum limit. By\nintroducing a new variable, say color field, carrying the color direction with\nit, this formulation enables us to restore and maintain color symmetry that was\nlost in the conventional MA gauge due to the naive separation of the gauge\npotential into diagonal and off-diagonal components. An advantage of this\nformulation is that we can define gaugeinvariant magnetic monopoles without\nrelying on specific gauges to investigate quark confinement from the viewpoint\nof dual superconductivity. In this talk, we will present the relevant lattice\nformulation to realize the above advantages and preliminary results of\nnumerical simulations to demonstrate the validity of this formulation. This\nSU(3) formulation is an extension of the SU(2) version already proposed by us\nin the previous conference.",
        "positive": "Bosonization of Majorana modes and edge states: We present a bosonization procedure which replaces fermions with generalized\nspin variables subject to local constraints. It requires that the number of\nMajorana modes per lattice site matches the coordination number modulo two. If\nthis condition is not obeyed, then bosonization introduces additional fermionic\nexcitations not present in the original model. In the case of one Majorana mode\nper site on a honeycomb lattice, we recover a sector of Kitaev's model. We\ndiscuss also decagonal and rectangular geometries and present bosonization of\nthe Hubbard model. For geometries with a boundary we find that certain\nfermionic edge modes naturally emerge. They are of different nature than edge\nmodes encountered in topological phases of matter. Euclidean representation for\nthe unconstrained version of a spin system of the type arising in our\nconstruction is derived and briefly studied by computing some exact averages\nfor small volumes."
    },
    {
        "anchor": "The n_f=2 residual mass in lattice HQET to alpha^3 order: We compute the so called residual mass in Lattice Heavy Quark Effective\nTheory to alpha^3 order in the n_f=2 (unquenched) case. The control of this\nadditive mass renormalization is crucial for the determination of the heavy\nquark mass from lattice simulations. We discuss the impact on an unquenched\ndetermination of the b-quark mass.",
        "positive": "Spontaneous CP violation on the lattice: At finite temperatures around the electroweak phase transition, the\nthermodynamics of the MSSM can be described by a three-dimensional two Higgs\ndoublet effective theory. This effective theory has a phase where CP is\nspontaneously violated. We study spontaneous CP violation with non-perturbative\nlattice simulations, and analyse whether one could end up in this phase for any\nphysical MSSM parameter values."
    },
    {
        "anchor": "Kaon B-parameter with NF=2 dynamical Wilson fermions: We present a preliminary study of the neutral kaon mixing bag parameter BK\nusing two flavors of dynamical Wilson fermions. We determine the matrix element\nof the relevant DeltaS=2 operator by using both the conventional approach and\nthe so called ``non-subtraction method'', and find that the latter leads to\nresults with smaller uncertainties. After having implemented non-perturbative\nrenormalization, we study the dependence of BK on the see quark mass. At our\nrelatively heavy values of quark masses (0.60<M_P/M_V<0.75) such a dependence\nis found to be negligible and the results, within the statistical accuracy, are\nconsistent with a quenched determination. As a preliminary result for the\nrenormalization group invariant parameter we quote BKRGI=1.02(25).",
        "positive": "Can axial U(1) anomaly disappear at high temperature?: In our recent study of two-flavor lattice QCD using chiral fermions, we find\nstrong suppression of axial U(1) anomaly above the critical temperature of\nchiral phase transition. Our simulation data also indicate suppression of\ntopological susceptibility. In this talk, we present both of our theoretical\nand numerical evidence for disappearance of axial U(1) anomaly, emphasizing the\nimportance of controlling lattice chiral symmetry violation, which is enhanced\nat high temperature."
    },
    {
        "anchor": "The Coulomb-Higgs transition of the three-parameter U(1)-Higgs model: We find a first order Coulomb--Higgs phase transition at moderately large\nvalues of the coupling $\\lambda$, and no evidence for a change of order at any\nfinite value of it.",
        "positive": "Numerical Study of Lattice Landau Gauge QCD and the Gribov Copy Problem: The infrared properties of lattice Landau gauge QCD of SU(3) are studied by\nmeasuring gluon propagator, ghost propagator, QCD running coupling and\nKugo-Ojima parameter of $\\beta=6.0, 16^4,24^4,32^4$ and $\\beta=6.4, 32^4, 48^4,\n56^4$ lattices. By the larger lattice measurements, we observe that the\nrunnning coupling measured by the product of the gluon dressing function and\nthe ghost dressing function squared rescaled to the perturbative QCD results\nnear the highest lattice momentum has the maximum of about 2.2 at around\n$q=0.5$ GeV/c, and behaves either approaching constant or even decreasing as\n$q$ approaches zero. The magnitude of the Kugo-Ojima parameter is getting\nlarger but staying around -0.83 in contrast to the expected value -1 in the\ncontinuum theory. We observe, however, there is an exceptional sample which has\nlarger magnitude of the Kugo-Ojima parameter and stronger infrared singularity\nof the ghost propagator. The reflection positivity of the 1-d Fourier transform\nof the gluon propagator of the exceptional sample is manifestly violated.\n  Gribov noise problem was studied by performing the fundamental modular gauge\n(FMG) fixing with use of the parallel tempering method of $\\beta=2.2, 16^4$\nSU(2) configurations. Findings are that the gluon propagator almost does not\nsuffer noises, but the Kugo-Ojima parameter and the ghost propagator in the FMG\nbecomes $\\sim 5$% less in the infrared region than those suffering noises. It\nis expected that these qualitative aspects seen in SU(2) will reflect in the\ninfrared properties of SU(3) QCD as well."
    },
    {
        "anchor": "Lattice formulation of 2D $\\mathcal{N}=(2,2)$ SQCD based on the B model\n  twist: We present a simple lattice formulation of two-dimensional\n$\\mathcal{N}=(2,2)$ $U(k)$ supersymmetric QCD (SQCD) with $N$ matter multiplets\nin the fundamental representation. The construction uses compact gauge link\nvariables and exactly preserves one linear combination of supercharges on the\ntwo-dimensional regular lattice. Artificial saddle points in the weak coupling\nlimit and the species doubling are evaded without imposing the admissibility. A\nperturbative power-counting argument indicates that the target supersymmetric\ntheory is realized in the continuum limit without any fine tuning.",
        "positive": "Roberge-Weiss endpoint at the physical point of $N_f = 2+1$ QCD: We study the phase diagram of $N_f = 2+1$ QCD in the $T - \\mu_B$ plane and\ninvestigate the critical point corresponding to the onset of the Roberge-Weiss\ntransition, which is found for imaginary values of $\\mu_B$. We make use of\nstout improved staggered fermions and of the tree level Symanzik gauge action,\nand explore four different sets of lattice spacings, corresponding to $N_t =\n4,6,8,10$, and different spatial sizes, in order to assess the universality\nclass of the critical point. The continuum extrapolated value of the endpoint\ntemperature is found to be $T_{\\rm RW} = 208(5)$ MeV, i.e. $T_{\\rm\n  RW}/T_c \\sim 1.34(7)$, where $T_c$ is the chiral pseudocritical temperature\nat zero chemical potential, while our finite size scaling analysis, performed\non $N_t = 4$ and $N_t = 6$ lattices, provides evidence for a critical point in\nthe $3d$ Ising universality class."
    },
    {
        "anchor": "Phase diagram and critical point evolution in NLO and NNLO strong\n  coupling lattice QCD: We investigate the chiral phase transition in the strong coupling lattice QCD\n(SC-LQCD) at finite temperature and density with finite coupling effects. We\nadopt one species of staggered fermion, and develop an analytic formulation\nbased on strong coupling and cluster expansions. We derive the effective\npotential as a function of two order parameters, the chiral condensate sigma\nand the vector potential \\omega_\\tau, in a self-consistent treatment of the\nnext-to-leading order (NLO) and the next-to-next-to-leading order (NNLO)\neffective action terms. Finite coupling effects lead to modifications of quark\nmass, chemical potential and the quark wave function renormalization factor.\nFinite coupling effects suppress the critical temperature at mu=0 (T_{c,mu=0}),\nwhile critical temperature at T=0 (mu_{c,T=0}) is not affected much. NNLO\ncorrections does not significantly affect T_{c,mu=0} and mu_{c,T=0}, but the\nphase diagram shape including the position of the critical point is sensitive\nto the NNLO effects. Partially chiral restored matter is found to exist in NLO\nand NNLO SC-LQCD.",
        "positive": "Staggered Fermion Thermodynamics using Anisotropic Lattices: Numerical simulations of full QCD on anisotropic lattices provide a\nconvenient way to study QCD thermodynamics with fixed physics scales and\nreduced lattice spacing errors. We report results from calculations with\n2-flavors of dynamical fermions where all bare parameters and hence the physics\nscales are kept constant while the temperature is changed in small steps by\nvarying only the number of the time slices. The results from a series of\nzero-temperature scale setting simulations are used to determine the Karsch\ncoefficients and the equation of state at finite temperatures."
    },
    {
        "anchor": "QED$_3$-inspired three-dimensional conformal lattice gauge theory\n  without fine-tuning: We construct a conformal lattice theory with only gauge degrees of freedom\nbased on the induced non-local gauge action in QED$_3$ coupled to large number\nof flavors $N$ of massless two-component Dirac fermions. This lattice system\ndisplays signatures of criticality in gauge observables, without any\nfine-tuning of couplings and can be studied without Monte Carlo critical\nslow-down. By coupling exactly massless fermion sources to the lattice gauge\nmodel, we demonstrate that non-trivial anomalous dimensions are induced in\nfermion bilinears depending on the dimensionless electric charge of the\nfermion. We present a proof-of-principle lattice computation of the\nWilson-coefficients of various fermion bilinear three-point functions. Finally,\nby mapping the charge $q$ of fermion in the model to a flavor $N$ in massless\nQED$_3$, we point to an universality in low-lying Dirac spectrum and an\nevidence of self-duality of $N=2$ QED$_3$.",
        "positive": "Update on a short-distance D^0-meson mixing calculation with $N_f=2+1$\n  flavors: We present an update on our calculation of the short-distance $D^0$-meson\nmixing hadronic matrix elements. The analysis is performed on the MILC\ncollaboration's $N_f=2+1$ asqtad configurations. We use asqtad light valence\nquarks and the Sheikoleslami-Wohlert action with the Fermilab interpretation\nfor the valence charm quark. SU(3), partially quenched, rooted, staggered\nheavy-meson chiral perturbation theory is used to extrapolate to the\nchiral-continuum limit. Systematic errors arising from the chiral-continuum\nextrapolation, heavy-quark discretization, and quark-mass uncertainties are\nfolded into the statistical errors from the chiral-continuum fits with methods\nof Bayesian inference. A preliminary error budget for all five operators is\npresented."
    },
    {
        "anchor": "Short-recurrence Krylov subspace methods for the overlap Dirac operator\n  at nonzero chemical potential: The overlap operator in lattice QCD requires the computation of the sign\nfunction of a matrix, which is non-Hermitian in the presence of a quark\nchemical potential. In previous work we introduced an Arnoldi-based Krylov\nsubspace approximation, which uses long recurrences. Even after the deflation\nof critical eigenvalues, the low efficiency of the method restricts its\napplication to small lattices. Here we propose new short-recurrence methods\nwhich strongly enhance the efficiency of the computational method. Using\nrational approximations to the sign function we introduce two variants, based\non the restarted Arnoldi process and on the two-sided Lanczos method,\nrespectively, which become very efficient when combined with multishift\nsolvers. Alternatively, in the variant based on the two-sided Lanczos method\nthe sign function can be evaluated directly. We present numerical results which\ncompare the efficiencies of a restarted Arnoldi-based method and the direct\ntwo-sided Lanczos approximation for various lattice sizes. We also show that\nour new methods gain substantially when combined with deflation.",
        "positive": "First results on QCD+QED with C* boundary conditions: Accounting for isospin-breaking corrections is critical for achieving\nsubpercent precision in lattice computations of hadronic observables. A way to\ninclude QED and strong-isospin-breaking corrections in lattice QCD calculations\nis to impose C$^\\star$ boundary conditions in space. Here, we demonstrate the\ncomputation of a selection of meson and baryon masses on two QCD and five\nQCD+QED gauge ensembles in this setup, which preserves locality, gauge and\ntranslational invariance all through the calculation. The generation of the\ngauge ensembles is performed for two volumes, and three different values of the\nrenormalized fine-structure constant at the U-symmetric point, corresponding to\nthe SU(3)-symmetric QCD in the two ensembles where the electromagnetic coupling\nis turned off. We also present our tuning strategy and, to the extent possible,\na cost analysis of the simulations with C$^\\star$ boundary conditions."
    },
    {
        "anchor": "HAL QCD potentials with non-zero total momentum and an application to\n  the $I=2$ $\u03c0\u03c0$ scattering: We consider the HAL QCD method in the system with non-zero total momentum\n(laboratory frame). We derive a relation between the NBS wave function in the\nlaboratory frame and the energy-independent non-local potential (HAL QCD\npotential), and propose the time-dependent method to extract the potential from\ncorrelation functions in the laboratory frame. We then apply this formulation\nto the $I=2$ $\\pi\\pi$ system to calculate the corresponding potential in the\nlaboratory frame, employing the 2+1 flavor gauge configuration on a $32^3\\times\n64$ lattice at the lattice spacing $a\\simeq 0.091$ fm and $m_\\pi \\simeq 700$\nMeV. While statistical errors are larger, the effective leading order (LO)\npotentials and corresponding phase shift agree with those from the HAL QCD\npotential in the center of mass (CM) frame. We also demonstrate the consistency\nin scattering phase shifts between the HAL QCD method in several frames and the\nfinite volume method. The HAL QCD method in the laboratory frame enlarges\napplicabilities of the method to investigate hadron interaction including\nmesonic resonances such as $\\rho$ and $\\sigma$.",
        "positive": "Spectroscopy of SU(4) gauge theory with two flavors of sextet fermions: We present a first look at the spectroscopy of SU(4) gauge theory coupled to\ntwo flavors of Dirac fermions in the two-index antisymmetric representation,\nwhich is a real representation. We compute meson and diquark masses, the\npseudoscalar and vector meson decay constants, and the masses of six-quark\nbaryons. We make comparisons with large-Nc expectations."
    },
    {
        "anchor": "Gauge Field Strength Tensor from the Overlap Dirac Operator: We derive the classical continuum limit of the operator tr$_s \\sigma_{\\mu\\nu}\nD^{ov}(x,x)$ with $D^{ov}$ being the overlap Dirac operator and show that it\ncorresponds to the gauge field strength tensor $F_{\\mu\\nu}(x)$.",
        "positive": "Symmetry and scaling in the Q-exact lattice (2,2) 2d Wess-Zumino model: As a nonperturbative check on the Q-exact lattice formulation, we demonstrate\nthat the continuum R-symmetries are recovered. We locate the critical domain of\nthe lattice theory. Aspects of the continuum nonrenormalization theorems are\nfound to be respected at finite lattice spacing. Preliminary attempts to\nextract critical exponents--another nonperturbative check--are discussed. All\nof our results are obtained from Monte Carlo simulations with dynamical\nfermions."
    },
    {
        "anchor": "Hadron structure from lattice QCD - outlook and future perspectives: We review results on hadron structure using lattice QCD simulations with pion\nmasses close or at to the physical value. We pay particular attention to recent\nsuccesses on the computation of the mass of the low-lying baryons and on the\nchallenges involved in evaluating energies of excited states and resonance\nparameters, as well as, in studies of nucleon structure.",
        "positive": "Lattice QCD thermodynamics with Wilson quarks: We review studies of QCD thermodynamics by lattice QCD simulations with\ndynamical Wilson quarks. After explaining the basic properties of QCD with\nWilson quarks at finite temperature including the phase structure and the\nscaling properties around the chiral phase transition, we discuss the critical\ntemperature, the equation of state and heavy-quark free energies."
    },
    {
        "anchor": "On the scaling of the electroweak interface tension at finite\n  temperature: We determine the interface tension of the finite-temperature electroweak\nphase transition in a numerical investigation of the SU(2)--Higgs model on a\nfour-dimensional lattice with temporal extension $L_t=3$. In this simulation\nthe chosen parameters correspond to a Higgs boson mass of about 16 GeV. As a\nresult the interface tension shows only small scaling violations in comparison\nwith previous studies for $L_t=2$ lattices. We also report on some experiences\nwith autocorrelations in the applied Monte Carlo simulations of two-phase\nsystems.",
        "positive": "Lattice QCD with Classical and Quantum Electrodynamics: We are doubtlessly familiar with some edition of Jackson's tome on\nelectrodynamics, and Schwinger's calculation of the anomalous magnetic moment\nof the electron in QED. From the perspective of strong interactions, however,\nelectromagnetic effects usually amount to negligible contributions. Despite\nthis fact, electromagnetic probes have always been a fundamental source for our\nknowledge of QCD experimentally. Elastic scattering of electrons off nucleons\nprovides us a window to their distributions of charge and magnetism. To account\nfor the spectrum of QCD at the percent level, moreover, we need isospin\nbreaking introduced from both quark masses and electric charges. This overview\nconcerns some of the prospects and progress of studying electromagnetic effects\nin QCD. Our focus is divided between classical and quantum effects. In\nclassical electromagnetic fields, the dynamical response of QCD to external\nconditions can be investigated. The vacuum and hadrons alike should be viewed\nas media which respond to external fields: both magnetize and polarize in\nmagnetic fields, for example. At the quantum level, electromagnetism and QCD\nrenormalize each other. In the era of high precision lattice computations, both\nstrong and electromagnetic contributions must be accounted for to make\npredictions at the percent level."
    },
    {
        "anchor": "Numerical results for the lightest bound states in $\\mathcal{N}=1$\n  supersymmetric SU(3) Yang-Mills theory: The physical particles in supersymmetric Yang-Mills theory (SYM) are bound\nstates of gluons and gluinos. We have determined the masses of the lightest\nbound states in SU(3) $\\mathcal{N}=1$ SYM. Our simulations cover a range of\ndifferent lattice spacings, which for the first time allows an extrapolation to\nthe continuum limit. Our results show the formation of a supermultiplet of\nbound states, which provides a clear evidence for unbroken supersymmetry.",
        "positive": "Symmetries of hadrons after unbreaking the chiral symmetry: We study hadron correlators upon artificial restoration of the spontaneously\nbroken chiral symmetry. In a dynamical lattice simulation we remove the lowest\nlying eigenmodes of the Dirac operator from the valence quark propagators and\nstudy evolution of the hadron masses obtained. All mesons and baryons in our\nstudy, except for a pion, survive unbreaking the chiral symmetry and their\nexponential decay signals become essentially better. From the analysis of the\nobserved spectroscopic patterns we conclude that confinement still persists\nwhile the chiral symmetry is restored. All hadrons fall into different chiral\nmultiplets. The broken U(1)_A symmetry does not get restored upon unbreaking\nthe chiral symmetry. We also observe signals of some higher symmetry that\nincludes chiral symmetry as a subgroup. Finally, from comparison of the \\Delta\n- N splitting before and after unbreaking of the chiral symmetry we conclude\nthat both the color-magnetic and the flavor-spin quark-quark interactions are\nof equal importance."
    },
    {
        "anchor": "Monopoles in Compact U(1) -- Anatomy of the Phase Transition: We present evidence that the existence of a first order phase transition in\ncompact U(1) with Wilson action is not related to monopole loops wrapping\naround the toroidal lattice, as has been previously suggested. Our analysis is\nbased on the suppression of such loops by `soft boundary conditions' that\ncorrespond to an infinitely large chemical potential for the monopoles on the\nboundary, during the updating process. It is observed that the double peak\nstructure characteristic for the first order phase transition reappears at\nsufficiently large lattice sizes and separations from the lattice boundary.",
        "positive": "Isospin breaking in octet baryon mass splittings: Using an SU(3) flavour symmetry breaking expansion in the quark mass, we\ndetermine the QCD component of the nucleon, Sigma and Xi mass splittings of the\nbaryon octet due to up-down (and strange) quark mass differences in terms of\nthe kaon mass splitting. Provided the average quark mass is kept constant, the\nexpansion coefficients in our procedure can be determined from computationally\ncheaper simulations with mass degenerate sea quarks and partially quenched\nvalence quarks. Both the linear and quadratic terms in the SU(3) flavour\nsymmetry breaking expansion are considered; it is found that the quadratic\nterms only change the result by a few percent, indicating that the expansion is\nhighly convergent."
    },
    {
        "anchor": "Extension of the Nielsen-Ninomiya theorem: The index theorem is employed to extend the no-go theorem for lattice chiral\nDirac fermions to translation non-invariant and non-local formulations.",
        "positive": "Instructive discussion of an effective block algorithm for baryon-baryon\n  correlators: We describe an approach for the efficient calculation of a large number of\nfour-point correlation functions for various baryon-baryon (BB) channels, which\nare the primary quantities for studying the nuclear and hyperonic nuclear\nforces from lattice quantum chromodynamics. Using the four-point correlation\nfunction of a proton-$\\Lambda$ system as a specific example, we discuss how an\neffective block algorithm significantly reduces the number of iterations. The\neffective block algorithm is applied to calculate 52 channels of the four-point\ncorrelation functions from nucleon$-$nucleon to $\\Xi-\\Xi$, in order to study\nthe complete set of isospin symmetric BB interactions. The elapsed times\nmeasured for hybrid parallel computation on BlueGene/Q demonstrate that the\nperformance of the present algorithm is reasonable for various combinations of\nthe number of OpenMP threads and the number of MPI nodes. The numerical results\nare compared with the results obtained using the unified contraction algorithm\nfor all computed sites of the 52 four-point correlators."
    },
    {
        "anchor": "Variance Reduction and Cluster Decomposition: It is a common problem in lattice QCD calculation of the mass of the hadron\nwith an annihilation channel that the signal falls off in time while the noise\nremains constant. In addition, the disconnected insertion calculation of the\nthree-point function and the calculation of the neutron electric dipole moment\nwith the $\\theta$ term suffer from a noise problem due to the $\\sqrt{V}$\nfluctuation. We identify these problems to have the same origin and the\n$\\sqrt{V}$ problem can be overcome by utilizing the cluster decomposition\nprinciple. We demonstrate this by considering the calculations of the glueball\nmass, the strangeness content in the nucleon, and the CP violation angle in the\nnucleon due to the $\\theta$ term. It is found that for lattices with physical\nsizes of 4.5 - 5.5 fm, the statistical errors of these quantities can be\nreduced by a factor of 3 to 4. The systematic errors can be estimated from the\nAkaike information criterion. For the strangeness content, we find that the\nsystematic error is of the same size as that of the statistical one when the\ncluster decomposition principle is utilized. This results in a 2 to 3 times\nreduction in the overall error.",
        "positive": "Controlling Residual Chiral Symmetry Breaking in Domain Wall Fermion\n  Simulations: At stronger gauge-field couplings, the domain wall fermion (DWF) residual\nmass, a measure of chiral symmetry breaking, grows rapidly. This measure is\nlargely due to near zero fermion eigenmodes of logarithm of the 4D transfer\nmatrix along the fifth dimension, and these eigenmodes increase rapidly at\nstrong coupling. To suppress these eigenmodes, we have added to the DWF path\nintegral a multiplicative weighting factor consisting of a ratio of\ndeterminants of Wilson-Dirac fermions having a chirally twisted mass with a\nlarge negative real component and a small imaginary chiral component. Numerical\nresults show that this weighting factor with an appropriate choice of twisted\nmasses significantly suppresses the residual mass while allowing adequate\ntopological tunneling."
    },
    {
        "anchor": "Generalized unparticles, zeros of the Green function, and momentum space\n  topology of the lattice model with overlap fermions: The definition of topological invariants $\\tilde{\\cal N}_4, \\tilde{\\cal N}_5$\nsuggested in \\cite{VZ2012} is extended to the case, when there are zeros and\npoles of the Green function in momentum space. It is shown how to extend the\nindex theorem suggested in \\cite{VZ2012} to this case. The non - analytical\nexceptional points of the Green function appear in the intermediate vacuum,\nwhich exists at the transition line between the massive vacua with different\nvalues of topological invariants. Their number is related to the jump\n$\\Delta\\tilde{\\cal N}_4$ across the transition. The given construction is\nillustrated by momentum space topology of the lattice model with overlap\nfermions. In the vicinities of the given points the fermion excitations appear\nthat cannot be considered as usual fermion particles. We, therefore, feel this\nappropriate to call them generalized unparticles. This notion is, in general\ncase different from the Georgi's unparticle. However, in the case of lattice\noverlap fermions the propagator of such excitations is indeed that of the\nfermionic unparticle suggested in \\cite{fermion_unparticle}.",
        "positive": "How to extract the \"Abelian\" part of double-winding Wilson loop: It is known that the naive Abelian Wilson loop defined by the Abelian\nprojection cannot reproduce the correct behavior of the double-winding Wilson\nloop. It is also known that the naive Abelian Wilson loop cannot reproduce the\ncorrect behavior of the Wilson loops in higher representations, but this\nproblem was recently solved by using the redefined \"Abelian\" Wilson loop. In\nthis talk, we will give another reason why this redefined \"Abelian\" Wilson loop\nbehaves correctly, and by following the same line of the argument, we will\npropose redefined \"Abelian\" double-winding Wilson loop which is considered to\nbehave correctly."
    },
    {
        "anchor": "Finite-size and quark mass effects on the QCD spectrum with two flavors: We have carried out spectrum calculations with two flavors of dynamical\nKogut-Susskind quarks on four lattice sizes from $8^3\\times 24$ to\n$16^3\\times24$ at couplings that correspond to chiral symmetry restoration for\na lattice with 6 time slices. We estimate that the linear spatial sizes of the\nlattices range from 1.8 to 3.6 fm. We find significant finite size effects for\nall particles between the smallest and largest volume with the larger quark\nmass that we study, $am_q=0.025$, where $a$ is the lattice spacing. The nucleon\nexperiences the largest effect of about 6 percent. We also study a lighter\nquark mass, $am_q=0.0125$, on the two largest lattices. Effects of the\ndynamical and valence quark masses on the hadron spectrum are studied both\ndirectly, by comparing the two simulations, and by extracting mass derivatives\nfrom the correlation functions. We do not find much improvement in the nucleon\nto rho mass ratio as we decrease the quark mass at this lattice spacing.\nFinally, we report on an unsuccessful attempt to see effects of the $\\rho\n\\rightarrow 2\\pi$ decay on the $\\rho$ mass, and on studies of Wilson and\nKogut-Susskind hadron masses with large valence quark masses. (The paper is\nalso available via anonymous ftp in a compressed PostScript file:\nfuji.physics.indiana.edu:/pub/milc/paper.ps.Z .)",
        "positive": "Tensor Networks and their use for Lattice Gauge Theories: Tensor Network States are ans\\\"atze for the efficient description of quantum\nmany-body systems. Their success for one dimensional problems, together with\nthe fact that they do not suffer from the sign problem and can address the\nsimulation of real time evolution, have turned them into one of the most\npromising techniques to study strongly correlated systems. In the realm of\nLattice Gauge Theories they can offer an alternative to standard lattice Monte\nCarlo calculations, which are suited for static properties and regimes where no\nsign problem appears. The application of Tensor Networks to this kind of\nproblems is a young but rapidly evolving research field. This paper reviews\nsome of the recent progress in this area, and how, using one dimensional models\nas testbench, some fundamental milestones have been reached that may pave the\nway to more ambitious goals."
    },
    {
        "anchor": "Meta-stable States in Quark-Gluon Plasma: We study the meta-stable states in high temperature phase of QCD\ncharacterised by nonzero expectation values for the imaginary part of the\nPolyakov loop. We consider $N_f= 2, 3$ dynamical staggered quarks, and carry\nout simulations at various values of the coupling $\\beta$ to observe these\nstates. In particular, we find the value of the coupling ($\\beta_m$) above\nwhich the meta-stable states appear. The resulting value of $\\beta_m$\ncorresponds to temperature $T_m \\gtrsim 750$MeV for $N_f=2$.",
        "positive": "Linear confinement and stress-energy tensor around static quark and\n  anti-quark pair -- Lattice simulation with Yang-Mills gradient flow --: We study the spatial distribution of the stress tensor around static\nquark-anti-quark pair in SU(3) lattice gauge theory. In particular, we reveal\nthe transverse structure of the stress tensor distribution in detail by taking\nthe continuum limit. The Yang-Mills gradient flow plays a crucial role to make\nthe stress tensor well-defined and derivable from the numerical simulations on\nthe lattice."
    },
    {
        "anchor": "Is there a flavor hierarchy in the deconfinement transition of QCD?: We present possible indications for flavor separation during the QCD\ncrossover transition based on continuum extrapolated lattice QCD calculations\nof higher order susceptibilities. We base our findings on flavor specific\nquantities in the light and strange quark sector. We propose a possible\nexperimental verification of our prediction, based on the measurement of higher\norder moments of identified particle multiplicities. Since all our calculations\nare performed at zero baryochemical potential, these results are of particular\nrelevance for the heavy ion program at the LHC.",
        "positive": "Thermodynamics with M\u00f6bius domain wall fermions near physical point II: We report on our finite temperature 2+1 flavor lattice QCD simulation to\nstudy the thermodynamic properties of QCD near the (pseudo) critical point\nemploying $N_T=12$ and $16$. The simulation points are chosen along the lines\nof constant physics. The quark mass for M\\\"obius domain-wall fermion are tuned\nby taking into account the residual mass either by fine-tuning the input quark\nmasses or by post-process using reweighting. In this talk, we focus on\nsimulation details and present some preliminary results."
    },
    {
        "anchor": "Continuum limit in numerical simulations of the $\\mathcal{N}=2$\n  Landau--Ginzburg model: The $\\mathcal{N}=2$ Landau--Ginzburg description provides a strongly\ninteracting Lagrangian realization of an $\\mathcal{N}=2$ superconformal field\ntheory. It is conjectured that one such example is given by the two-dimensional\n$\\mathcal{N}=2$ Wess--Zumino model. Recently, the conjectured correspondence\nhas been studied by using numerical techniques based on lattice field theory;\nthe scaling dimension and the central charge have been directly measured. We\nstudy a single superfield with a cubic superpotential, and give an\nextrapolation method to the continuum limit. Then, on the basis of a\nsupersymmetric-invariant numerical algorithm, we perform a precision\nmeasurement of the scaling dimension through a finite-size scaling analysis.",
        "positive": "Comparison of topology changing update algorithms: In modern lattice simulations, conventional update algorithms do not allow\nfor tunneling between topological sectors at fine lattice spacings. We compare\nthe viability of multiple less commonly used algorithms (metadynamics,\ninstanton updates, and multiscale thermalization) with respect to proper\nsampling of all topological sectors in the Schwinger model. We briefly comment\non the prospects of applying these methods to 4-dimensional SU(3) simulations."
    },
    {
        "anchor": "Mollifying Quantum Field Theory or Lattice QFT in Minkowski Spacetime\n  and Symmetry Breaking: This work develops and applies the concept of mollification in order to\nsmooth out highly oscillatory exponentials. This idea, known for quite a while\nin the mathematical community (mollifiers are a means to smooth distributions),\nis new to numerical Quantum Field Theory. It is potentially very useful for\ncalculating phase transitions [highly oscillatory integrands in general], for\ncomputations with imaginary chemical potentials and Lattice QFT in Minkowski\nspacetime.",
        "positive": "Axial U(1) current in Grabowska and Kaplan's formulation: Recently, Grabowska and Kaplan suggested a non-perturbative formulation of a\nchiral gauge theory, which consists of the conventional domain-wall fermion and\na gauge field that evolves by the gradient flow from one domain wall to the\nother. In this paper, we discuss the U(1) axial-vector current in 4 dimensions\nusing this formulation. We introduce two sets of domain-wall fermions belonging\nto complex conjugate representations so that the effective theory is a\n4-dimensional vector-like gauge theory. Then, as a natural definition of the\naxial-vector current, we consider a current that generates the simultaneous\nphase transformations for the massless modes in 4 dimensions. However, this\ncurrent is exactly conserved and does not reproduce the correct anomaly. In\norder to investigate this point precisely, we consider the mechanism of the\nconservation. We find that this current includes not only the axial current on\nthe domain wall but also a contribution from the bulk, which is non-local in\nthe sense of 4-dimensional fields. Therefore, the local current is obtained by\nsubtracting the bulk contribution from it."
    },
    {
        "anchor": "Quenched scalar meson correlator with Domain Wall Fermions: We study the singlet and non-singlet scalar-meson masses using domain wall\nfermions and the quenched approximation. The singlet mass is found to be\nsmaller than the non-singlet mass and indicates that the lowest singlet meson\nstate could be lighter than 1 GeV. The two-point functions for very small quark\nmasses are compared with expectations from the small-volume chiral perturbation\ntheory and the presence of fermionic zero modes.",
        "positive": "The b quark mass from lattice nonrelativistic QCD: We present the first two-loop calculation of the heavy quark energy shift in\nlattice nonrelativistic QCD (NRQCD). This calculation allow us to extract a\npreliminary prediction of $m_b(m_b, n_f = 5) = 4.25(12)$ GeV for the mass of\nthe b quark from lattice NRQCD simulations performed with a lattice of spacing\n$a=0.12$fm. Our result is an improvement on a previous determination of the b\nquark mass from unquenched lattice NRQCD simulations, which was limited by the\nuse of one-loop expressions for the energy shift. Our value is in good\nagreement with recent results of $m_b(m_b) = 4.163(16)$ GeV from QCD sum rules\nand $m_b(m_b, n_f = 5) = 4.170(25)$ GeV from realistic lattice simulations\nusing highly-improved staggered quarks. We employ a mixed strategy to simplify\nour calculation. Ghost, gluon and counterterm contributions to the energy shift\nand mass renormalisation are extracted from quenched high-beta simulations\nwhilst fermionic contributions are calculated using automated lattice\nperturbation theory. Our results demonstrate the effectiveness of such a\nstrategy."
    },
    {
        "anchor": "Spontaneous Flavor and Parity Breaking with Wilson Fermions: We discuss the phase diagram of Wilson fermions in the $m_0$--$g^2$ plane for\ntwo-flavor QCD. We argue that, as originally suggested by Aoki, there is a\nphase in which flavor and parity are spontaneously broken. Recent numerical\nresults on the spectrum of the overlap Hamiltonian have been interpreted as\nevidence against Aoki's conjecture. We show that they are in fact consistent\nwith the presence of a flavor-parity broken ``Aoki phase''. We also show how,\nas the continuum limit is approached, one can study the lattice theory using\nthe continuum chiral Lagrangian supplemented by additional terms proportional\nto powers of the lattice spacing. We find that there are two possible phase\nstructures at non-zero lattice spacing: (1) there is an Aoki phase of width\n$\\Delta m_0 \\sim a^3$ with two massless Goldstone pions; (2) there is no\nsymmetry breaking, and all three pions have an equal non-vanishing mass of\norder $a$. Present numerical evidence suggests that the former option is\nrealized for Wilson fermions. Our analysis then predicts the form of the pion\nmasses and the flavor-parity breaking condensate within the Aoki phase. Our\nanalysis also applies for non-perturbatively improved Wilson fermions.",
        "positive": "Excited hadrons on the lattice: Baryons: We present results for masses of excited baryons from a quenched calculation\nwith Chirally Improved quarks at pion masses down to 350 MeV. Our analysis of\nthe correlators is based on the variational method. In order to provide a large\nbasis set for spanning the physical states, we use interpolators with different\nDirac structures and Jacobi smeared quark sources of different width. Our\nspectroscopy results for a wide range of ground state and excited baryons are\ndiscussed."
    },
    {
        "anchor": "Extending complex Langevin simulations to full QCD at nonzero density: Simulations of full QCD at nonzero baryon density using light quark masses\nare presented. The sign problem is evaded by the usage of the complex Langevin\nequation. The simulations are stabilized by the gauge cooling procedure for\nsmall lattice spacings. The method allows simulations at high densities, up to\nthe saturation. The sign average is measured in the full as well as the\nphasequenched theory. Results are compared to the HQCD approach, in which the\nspatial hopping terms of fermionic variables are dropped, and good agreement is\nfound at large masses.",
        "positive": "Higher representations on the lattice: perturbative studies: We present analytical results to guide numerical simulations with Wilson\nfermions in higher representations of the colour group. The ratio of $\\Lambda$\nparameters, the additive renormalization of the fermion mass, and the\nrenormalization of fermion bilinears are computed in perturbation theory,\nincluding cactus resummation. We recall the chiral Lagrangian for the different\npatterns of symmetry breaking that can take place with fermions in higher\nrepresentations, and discuss the possibility of an Aoki phase as the fermion\nmass is reduced at finite lattice spacing."
    },
    {
        "anchor": "Gauge fixing using overrelaxation and simulated annealing on GPUs: We adopt CUDA-capable Graphic Processing Units (GPUs) for Coulomb, Landau and\nmaximally Abelian gauge fixing in 3+1 dimensional SU(3) lattice gauge field\ntheories. The local overrelaxation algorithm is perfectly suited for highly\nparallel architectures. Simulated annealing preconditioning strongly increases\nthe probability to reach the global maximum of the gauge functional. We give\nperformance results for single and double precision. To obtain our maximum\nperformance of ~300 GFlops on NVIDIA's GTX 580 a very fine grained degree of\nparallelism is required due to the register limits of NVIDIA's Fermi GPUs: we\nuse eight threads per lattice site, i.e., one thread per SU(3) matrix that is\ninvolved in the computation of a site update.",
        "positive": "Ward identities in $\\mathcal{N}=1$ supersymmetric SU(3) Yang-Mills\n  theory on the lattice: The introduction of a space-time lattice as a regulator of field theories\nbreaks symmetries associated with continuous space-time, i.e.\\ Poincar{\\'e}\ninvariance and supersymmetry. A non-zero gluino mass in the supersymmetric\nYang-Mills theory causes an additional soft breaking of supersymmetry. We\nemploy the lattice form of SUSY Ward identities, imposing that their continuum\nform would be recovered when removing the lattice regulator, to obtain the\ncritical hopping parameter where broken symmetries can be recovered."
    },
    {
        "anchor": "Finite Volume Errors in $B_K$: We discuss finite volume errors in our calculations of $B_K$ using improved\nstaggered fermions on the MILC asqtad lattices. Using GPUs, we are now able to\nextrapolate using next-to-leading order (NLO) staggered SU(2) chiral\nperturbation theory including the finite volume corrections arising from pion\nloops. We find that the impact of FV fitting is very small, giving a 0.5% shift\nin the continuum limit.",
        "positive": "NSPT for $O(N)$ non-linear sigma model: the larger $N$ the better: The $O(N)$ non-linear sigma model (NLSM) is an example of field theory on a\ntarget space with nontrivial geometry. One interesting feature of NLSM is\nasymptotic freedom, which makes perturbative calculations interesting. Given\nthe successes in Lattice Gauge Theories, Numerical Stochastic Perturbation\nTheory (NSPT) is a natural candidate for performing high-order computations\nalso in the case of NLSM. However, in low-dimensional systems NSPT is known to\ndisplay statistical fluctuations substantially increasing for increasing\norders. In this work, we explore how for $O(N)$ NLSM this behaviour is strongly\ndependent on $N$. As largely expected on general grounds, the larger is $N$,\nthe larger is the order at which a NSPT computation can be effectively\nperformed."
    },
    {
        "anchor": "First Calculation of Hyperon Axial Couplings from Lattice QCD: In this work, we report the first lattice calculation of hyperon axial\ncouplings, using the 2+1-flavor MILC configurations and domain-wall fermion\nvalence quarks. Both the $\\Sigma$ and $\\Xi$ axial couplings are computed for\nthe first time in lattice QCD. In particular we find that $g_{\\Sigma\\Sigma} =\n0.450(21)_{\\rm stat}(27)_{\\rm syst}$ and $g_{\\Xi\\Xi} = -0.277(15)_{\\rm\nstat}(19)_{\\rm syst}$.",
        "positive": "QCD at Non-Zero Density : Lattice Results: A concise review of the progress of lattice calculations at non-zero density\nsince QM2006 is given, with emphasis on the high baryon density, low\ntemperature domain. Possibilities for exploring densities higher than those\nstudied by standard techniques are analysed. The phase transitions of cold,\ndense matter, where the sign problem remains severe, are discussed in the\ncontext of QCD-like models and approximations to QCD."
    },
    {
        "anchor": "Spectrum of Large N Glueballs: Holography vs Lattice: Recently there has been a notable progress in the study of glueball states in\nlattice gauge theories, in particular extrapolating their spectrum to the limit\nof large number of colors $N$. In this note we compare the large $N$ lattice\nresults with the holographic predictions, focusing on the Klebanov-Strassler\nmodel. We note that glueball spectrum demonstrates approximate universality\nacross a range of gauge theory models. Because of this universality the\nholographic models can give reliable predictions for the spectrum of pure\n$SU(N)$ Yang-Mills theories with and without supersymmetry. This is especially\nimportant for the supersymmetric theories, for which no firm lattice\npredictions exist yet, and the holographic models remain the most tractable\napproach. For non-supersymmetric pure $SU(N)$ theories with large $N$ we find\nan agreement within 5-8% between the lattice and holographic predictions for\nthe mass ratios of the lightest states in various sectors. In particular both\nlattice and holography give predictions for the $2^{++}$ and $1^{--}$ mass\nratio, consistent with the known constraints on the pomeron and odderon Regge\ntrajectories.",
        "positive": "Simulating the Femtouniverse on a Quantum Computer: We compute the low-lying spectrum of 4D SU(2) Yang-Mills in a finite volume\nusing quantum simulations. In contrast to small-volume lattice truncations of\nthe Hilbert space, we employ toroidal dimensional reduction to the\n``femtouniverse\" matrix quantum mechanics model. In this limit the theory is\nequivalent to the quantum mechanics of three interacting particles moving\ninside a 3-ball with certain boundary conditions. We use the variational\nquantum eigensolver and quantum subspace expansion techniques to compute the\nstring tension to glueball mass ratio near the small/large-volume transition\npoint, finding qualitatively good agreement with large volume Euclidean lattice\nsimulations."
    },
    {
        "anchor": "Investigating BSM Models with Large Scale Separation: Mass-split systems based on a conformal infrared fixed point provide a\nlow-energy effective description of beyond the standard model systems with\nlarge scale separation. We report results of exploratory investigations with\nfour light and eight heavy flavors using staggered fermions, and up to five\ndifferent values for the light flavor mass, five different heavy flavor masses,\nand two values of the bare gauge coupling.",
        "positive": "Exact duality transformations for sigma models and gauge theories: We present an exact duality transformation in the framework of Statistical\nMechanics for various lattice models with non-Abelian global or local\nsymmetries. The transformation applies to sigma models with variables in a\ncompact Lie group G with global GxG-symmetry (the chiral model) and with\nvariables in coset spaces G/H and a global G-symmetry (for example, the\nnon-linear O(N) or RP^N models) in any dimension d>=1. It is also available for\nlattice gauge theories with local gauge symmetry in dimensions d>=2 and for the\nmodels obtained from minimally coupling a sigma model of the type mentioned\nabove to a gauge theory. The duality transformation maps the strong coupling\nregime of the original model to the weak coupling regime of the dual model.\nTransformations are available for the partition function, for expectation\nvalues of fundamental variables (correlators and generalized Wilson loops) and\nfor expectation values in the dual model which correspond in the original\nformulation to certain ratios of partition functions (free energies of\ndislocations, vortices or monopoles). Whereas the original models are\nformulated in terms of compact Lie groups G and H, coset spaces G/H and\nintegrals over them, the configurations of the dual model are given in terms of\nrepresentations and intertwiners of G. They are spin networks and spin foams.\nThe partition function of the dual model describes the group theoretic aspects\nof the strong coupling expansion in a closed form."
    },
    {
        "anchor": "Comment on hep-lat/9901005 v1-v3 by W. Bietenholz: I comment on the above paper(s) discussing the issue of non-ultralocality for\nGinsparg-Wilson fermionic actions. The purpose of this note is to point out\nthat the new claim in \"v3\" (Feb 24, 2000), alleging the proof for \"all\nGinsparg-Wilson fermions\", might not be substantiated. The remarkable evolution\nof versions of this paper is put in context with the literature existing at the\ntime of their appearance.",
        "positive": "Thermal QCD in a non-uniform magnetic background: Off-central heavy-ion collisions are known to feature magnetic fields with\nmagnitudes and characteristic gradients corresponding to the scale of the\nstrong interactions. In this work, we employ equilibrium lattice simulations of\nthe underlying theory, QCD, involving similar inhomogeneous magnetic field\nprofiles to achieve a better understanding of this system. We simulate three\nflavors of dynamical staggered quarks with physical masses at a range of\nmagnetic fields and temperatures, and extrapolate the results to the continuum\nlimit. Analyzing the impact of the field on the quark condensate and the\nPolyakov loop, we find non-trivial spatial features that render the QCD medium\nqualitatively different as in the homogeneous setup, especially at temperatures\naround the transition. In addition, we construct leading-order chiral\nperturbation theory for the inhomogeneous background and compare its prediction\nto our lattice results at low temperature. Our findings will be useful to\nbenchmark effective theories and low-energy models of QCD for a better\ndescription of peripheral heavy-ion collisions."
    },
    {
        "anchor": "First study of $B \\to \u03c0$ semileptonic decay form factors using NRQCD: We present a quenched calculation of the form factors of the semileptonic\nweak decay $B \\to \\pi l \\bar{\\nu}$ with $O(1/m_Q)$ NRQCD heavy quark and Wilson\nlight quark on a $16^3 \\times 32$ lattice at $\\beta=5.8$. The form factors are\nevaluated at six heavy quark masses, in the range of $m_Q \\sim 1.5-8$ GeV.\n$1/m_Q$ dependence of matrix elements are investigated and compared with HQET\npredictions. We observe clear signal for the form factors near $q^2_{max}$,\neven at the $b$-quark mass range. $f^0(q^2_{max})$ is compared with\n$f_B/f_{\\pi}$ based on the soft pion theorem and significant difference is\nobserved.",
        "positive": "Staggered fermions for chiral gauge theories: Test on a two-dimensional\n  axial-vector model: As a first step towards constructing chiral models on the lattice with\nstaggered fermions, we study a U(1) model with axial-vector coupling to an\nexternal gauge field in two dimensions. In our approach gauge invariance is\nbroken, but it is restored in the classical continuum limit. We find that the\ncontinuum divergence relations for the vector and axial-vector currents are\nreproduced, up to contact terms, which we determine analytically. The current\ndivergence relations are also studied numerically for smooth external gauge\nfields with topological charge zero. We furthermore investigate the effect of\nfluctuating gauge transformations and of gauge configurations with non-trivial\ntopological charge."
    },
    {
        "anchor": "Lattice QED and Universality of the Axial Anomaly: We give a perturbative proof that U(1) lattice gauge theories generate the\naxial anomaly in the continuum limit under very general conditions on the\nlattice Dirac operator. These conditions are locality, gauge covariance and the\nabsense of species doubling. They hold for Wilson fermions as well as for\nrealizations of the Dirac operator that satisfy the Ginsparg-Wilson relation.\nThe proof is based on the lattice power counting theorem. The results\ngeneralize to non-abelian gauge theories.",
        "positive": "Jarzynski's theorem for lattice gauge theory: Jarzynski's theorem is a well-known equality in statistical mechanics, which\nrelates fluctuations in the work performed during a non-equilibrium\ntransformation of a system, to the free-energy difference between two\nequilibrium ensembles. In this article, we apply Jarzynski's theorem in lattice\ngauge theory, for two examples of challenging computational problems, namely\nthe calculation of interface free energies and the determination of the\nequation of state. We conclude with a discussion of further applications of\ninterest in QCD and in other strongly coupled gauge theories, in particular for\nthe Schroedinger functional and for simulations at finite density using\nreweighting techniques."
    },
    {
        "anchor": "Finite Temperature LGT in a Finite Box with BPS Monopole Boundary\n  Conditions: Finite temperature SU(2) lattice gauge theory is investigated in a 3D cubic\nbox with fixed boundary conditions (b.c.) provided by a discretized, static BPS\nmonopole solution with varying core scale ${\\mu}$. For discrete ${\\mu}$-values\nwe find stable classical solutions either of electro-magnetic ('dyon') or of\npurely magnetic type inside the box. Near the deconfinement transition we study\nthe influence of the b.c. on the quantized fields inside the box. In contrast\nto the purely magnetic background field case, for the dyon case we observe\nconfinement for temperatures above the usual critical one.",
        "positive": "Entanglement Entropy of ($2+1$)-Dimensional SU(2) Lattice Gauge Theory: We study the entanglement entropy of Hamiltonian SU(2) lattice gauge theory\nin $2+1$ dimensions on linear plaquette chains and show that the entanglement\nentropies of both ground and excited states follow Page curves. The transition\nof the subsystem size dependence of the entanglement entropy from the area law\nfor the ground state to the volume law for highly excited states is found to be\ndescribed by a universal crossover function. Quantum many-body scars in the\nmiddle of the spectrum, which are present in the electric flux truncated\nHilbert space, where the gauge theory can be mapped onto an Ising model,\ndisappear when higher electric field representations are included in the\nHilbert space basis. This suggests the continuum $(2+1)$-dimensional SU(2)\ngauge theory is a ``fast'' scrambler."
    },
    {
        "anchor": "Scaling and Topological Charge of a Fixed Point Action for $SU(2)$ Gauge\n  Theory: We construct a few parameter approximate fixed point action for SU(2) pure\ngauge theory and subject it to scaling tests, via Monte Carlo simulation. We\nmeasure the critical coupling for deconfinement for lattices of temporal extent\n$N_t=2$, 3, 4, the torelon mass at fixed physical volume, and the string\ntension (and heavy quark potential) from Wilson loops. We calculate the\ntopological susceptibility using inverse blocking and show that it scales over\nthe observed range of lattice spacings.",
        "positive": "Locality of optimal lattice domain-wall fermions: It is shown that the effective 4D lattice Dirac operator of optimal lattice\ndomain-wall fermions with finite N_s (in the fifth dimension) is exponentially\nlocal for sufficiently smooth gauge background."
    },
    {
        "anchor": "Infrared properties of propagators in Landau-gauge pure Yang-Mills\n  theory at finite temperature: The finite-temperature behavior of gluon and of Faddeev-Popov-ghost\npropagators is investigated for pure SU(2) Yang-Mills theory in Landau gauge.\nWe present nonperturbative results, obtained using lattice simulations and\nDyson-Schwinger equations. Possible limitations of these two approaches, such\nas finite-volume effects and truncation artifacts, are extensively discussed.\nBoth methods suggest a very different temperature dependence for the magnetic\nsector when compared to the electric one. In particular, a clear thermodynamic\ntransition seems to affect only the electric sector. These results imply in\nparticular the confinement of transverse gluons at all temperatures and they\ncan be understood inside the framework of the so-called Gribov-Zwanziger\nscenario of confinement.",
        "positive": "Dual condensate, dressed Polyakov loops and center symmetry from Dirac\n  spectra: We construct a novel observable for finite temperature QCD that relates\nconfinement and chiral symmetry. It uses phases as boundary conditions for the\nfermions. We discuss numerical and analytical aspects of this observable, like\nits spectral behavior below and above the critical temperature, as well as the\nconnection to chiral condensate, center symmetry and the canonical ensemble."
    },
    {
        "anchor": "Thimble regularization at work for Gauge Theories: from toy models\n  onwards: A final goal for thimble regularization of lattice field theories is the\napplication to lattice QCD and the study of its phase diagram. Gauge theories\npose a number of conceptual and algorithmic problems, some of which can be\naddressed even in the framework of toy models. We report on our progresses in\nthis field, starting in particular from first successes in the study of one\nlink models.",
        "positive": "Chirally improving Wilson fermions II. Four-quark operators: In this paper we discuss how the peculiar properties of twisted lattice QCD\nat maximal twist can be employed to set up a consistent computational scheme in\nwhich, despite the explicit breaking of chiral symmetry induced by the presence\nof the Wilson and mass terms in the action, it is possible to completely bypass\nthe problem of wrong chirality and parity mixings in the computation of the\nCP-conserving matrix elements of the $\\Delta S=1,2$ effective weak Hamiltonian\nand at the same time have a positive determinant for non-degenerate quarks as\nwell as full O($a$) improvement in on-shell quantities with no need of\nimproving the lattice action and the operators."
    },
    {
        "anchor": "Towards QCD thermodynamics using exact chiral symmetry on lattice: The thermodynamics of massless ideal gas of overlap quarks has been\ninvestigated numerically for both zero and nonzero baryon chemical potential\n$\\mu$. While the parameter M has been shown to be irrelevant in the continuum\nlimit, it is shown numerically that the continuum limit can be reached with\nrelatively coarser lattices for certain range of M. Numerical limitation of the\nexisting method of introduction of chemical potential in the overlap formalism\nis discussed. We have also studied the energy density of free domain wall\nfermions in the absence of $\\mu$ and estimated the extent of lattice in the\nfifth dimension $L_5$ for which the overlap results are recovered.\nInterestingly, this value of $L_5$ is also minimum for the same range of M\nfound in the overlap case.",
        "positive": "Up, down, and strange nucleon axial form factors from lattice QCD: We report a calculation of the nucleon axial form factors $G_A^q(Q^2)$ and\n$G_P^q(Q^2)$ for all three light quark flavors $q\\in\\{u,d,s\\}$ in the range\n$0\\leq Q^2\\lesssim 1.2\\text{ GeV}^2$ using lattice QCD. This work was done\nusing a single ensemble with pion mass 317 MeV and made use of the hierarchical\nprobing technique to efficiently evaluate the required disconnected loops. We\nperform nonperturbative renormalization of the axial current, including a\nnonperturbative treatment of the mixing between light and strange currents due\nto the singlet-nonsinglet difference caused by the axial anomaly. The form\nfactor shapes are fit using the model-independent $z$ expansion. From\n$G_A^q(Q^2)$, we determine the quark contributions to the nucleon spin and\naxial radii. By extrapolating the isovector $G_P^{u-d}(Q^2)$, we obtain the\ninduced pseudoscalar coupling relevant for ordinary muon capture and the\npion-nucleon coupling constant. We find that the disconnected contributions to\n$G_P$ form factors are large, and give an interpretation based on the dominant\ninfluence of the pseudoscalar poles in these form factors."
    },
    {
        "anchor": "Measuring infrared contributions to the QCD pressure: For the pressure (or free energy) of QCD, four-dimensional (4d) lattice data\nis available at zero baryon density up to a few times the critical temperature\n$T_c$. Perturbation theory, on the other hand, has serious convergence problems\neven at very high temperatures. In a combined analytical and three-dimensional\n(3d) lattice method, we show that it is possible to compute the QCD pressure\nfrom about $2 T_c$ to infinity. The numerical accuracy is good enough to\nresolve in principle, e.g., logarithmic contributions related to 4-loop\nperturbation theory.",
        "positive": "Finite-Size Scaling at $\u03be/L \\gg 1$: We present a simple and powerful method for extrapolating finite-volume Monte\nCarlo data to infinite volume, based on finite-size-scaling theory. We discuss\ncarefully its systematic and statistical errors, and we illustrate it using\nthree examples: the two-dimensional three-state Potts antiferromagnet on the\nsquare lattice, and the two-dimensional $O(3)$ and $O(\\infty)$ $\\sigma$-models.\nIn favorable cases it is possible to obtain reliable extrapolations (errors of\na few percent) even when the correlation length is 1000 times larger than the\nlattice."
    },
    {
        "anchor": "Improved Transfer-Matrix Schemes of Phenomenological Renormalization: Different phenomenological RG transformations based on scaling relations for\nthe derivatives of the inverse correlation length and singular part of the\nfree-energy density are considered. These transformations are tested on the 2D\nsquare Ising and Potts models as well as on the 3D simple-cubic Ising model.\nVariants of RG equations yielding more accurate results than Nightingale's RG\nscheme are obtained. In the 2D case the finite-size equations which give the\n{\\it exact} values of the critical point or the critical exponent are found.",
        "positive": "Effects of partial quenching and staggered fermions on the scalar\n  correlator: We determine the mass of the lightest quark-antiquark scalar meson with I=1\nusing the simulation with two dynamical Domain Wall Fermions. The conventional\nexponential fit of the scalar correlator is justified in this case giving the\nmass 1.58 +/- 0.34 GeV. In general the scalar correlator receives also the\nbubble contribution, which is the intermediate state with two pseudoscalar\nmesons. This contribution is sizable at light quark masses and has to be\nincorporated in the fit of the scalar correlator in order to extract the scalar\nmeson mass. We provide predictions for the bubble contribution in Partially\nQuenched ChPT, Staggered ChPT and ChPT for Mixed quark actions. We find that\nthe bubble contribution is significantly affected by the unphysical\napproximations that are employed in simulations. It can render the negative\nsign and unphysical effective mass 2*Mpi in the scalar correlator with I=1."
    },
    {
        "anchor": "Fixed Point Gauge Actions with Fat Links: Scaling and Glueballs: A new parametrization is introduced for the fixed point (FP) action in SU(3)\ngauge theory using fat links. We investigate its scaling properties by means of\nthe static quark-antiquark potential and the dimensionless quantities $r_0 T_c,\nT_c/\\sqrt{\\sigma}$ and $r_0 \\sqrt{\\sigma}$, where $T_c$ is the critical\ntemperature of the deconfining phase transition, $r_0$ is the hadronic scale\nand $\\sigma$ is the effective string tension. These quantities scale even on\nlattices as coarse as $a \\approx 0.3$ fm. We also measure the glueball spectrum\nand obtain $m_{0^{++}}=1627(83)$ MeV and $m_{2^{++}}=2354(95)$ MeV for the\nmasses of the scalar and tensor glueballs, respectively.",
        "positive": "Quark-Gluon Plasma: from lattice simulations to experimental results: Theoretical studies of quarkonia can elucidate some of the important\nproperties of the quark--gluon plasma, the state of matter realised when the\ntemperature exceeds 150 MeV, currently probed by heavy-ion collisions\nexperiments at BNL and the LHC. We report on our results of lattice studies of\nbottomonia for temperatures in the range 100 MeV < T < 450 MeV, introducing and\ndiscussing the methodologies we have applied. Of particular interest is the\nanalysis of the spectral functions, where Bayesian methods borrowed and adapted\nfrom nuclear and condensed matter physics have proven very successful."
    },
    {
        "anchor": "Abelian dominance and adjoint color sources: Abelian dominance in the case of color sources in the fundamental\nrepresentation is shown to follow from certain properties of maximal abelian\nprojected SU(2) gauge theory. The possibility of having an analog of abelian\ndominance in the case of adjoint representation sources is addressed in the\nsame framework.",
        "positive": "Electromagnetic Splittings and Light Quark Masses: A method for computing electromagnetic properties of hadrons in lattice QCD\nis described. The electromagnetic field is introduced dynamically, using a\nnoncompact formulation. Employing enhanced electric charges, the dependence of\nthe pseudoscalar meson mass on the (anti)quark charges and masses can be\naccurately calculated. At $\\beta=5.7$ with Wilson action, the $\\pi^+-\\pi^0$\nsplitting is found to be $4.9(3)$ MeV. Using the measured $K^0-K^+$ splitting,\nwe also find $m_u/m_d = .512(6)$. Systematic errors are discussed. Preliminary\nresults for vector meson splittings are also presented.}"
    },
    {
        "anchor": "The order of the quantum chromodynamics transition predicted by the\n  standard model of particle physics: We determine the nature of the QCD transition using lattice calculations for\nphysical quark masses. Susceptibilities are extrapolated to vanishing lattice\nspacing for three physical volumes, the smallest and largest of which differ by\na factor of five. This ensures that a true transition should result in a\ndramatic increase of the susceptibilities.No such behaviour is observed: our\nfinite-size scaling analysis shows that the finite-temperature QCD transition\nin the hot early Universe was not a real phase transition, but an analytic\ncrossover (involving a rapid change, as opposed to a jump, as the temperature\nvaried). As such, it will be difficult to find experimental evidence of this\ntransition from astronomical observations.",
        "positive": "Exploring finite density QCD phase transition with canonical approach\n  -Power of multiple precision computation-: The canonical approach for finite density lattice QCD has a numerical\ninstability. This instability makes it difficult to use the method reliably at\nthe finite real chemical potential region. We studied this instability in\ndetail and found that it is caused by the cancellation of significant digits.\nIn order to reduce the effect of this cancellation, we adopt the multiple\nprecision calculation for our discrete Fourier transformation (DFT) program,\nand we get the canonical partition function Zc(n,T) with required accuracy.\nFrom the obtained Zc(n,T), we calculate Lee--Yang zero distribution varying the\nnumber of significant digits. As a result, some curves surround the origin in\nthe fugacity plane, but they are moved by varying the number of significant\ndigits. Hence, we conclude that these curves are pseudo phase transition lines,\nand not real ones."
    },
    {
        "anchor": "Axial couplings and strong decay widths of heavy hadrons: We calculate the axial couplings of mesons and baryons containing a heavy\nquark in the static limit using lattice QCD. These couplings determine the\nleading interactions in heavy hadron chiral perturbation theory and are central\nquantities in heavy quark physics, as they control strong decay widths and the\nlight-quark mass dependence of heavy hadron observables. Our analysis makes use\nof lattice data at six different pion masses, 227 MeV < m_\\pi < 352 MeV, two\nlattice spacings, a=0.085, 0.112 fm, and a volume of (2.7 fm)^3. Our results\nfor the axial couplings are g_1=0.449(51), g_2=0.84(20), and g_3=0.71(13),\nwhere g_1 governs the interaction between heavy-light mesons and pions and\ng_{2,3} are similar couplings between heavy-light baryons and pions. Using our\nlattice result for g_3, and constraining 1/m_Q corrections in the strong decay\nwidths with experimental data for \\Sigma_c^{(*)} decays, we obtain\n\\Gamma[\\Sigma_b^{(*)} \\to \\Lambda_b \\pi^\\pm] = 4.2(1.0), 4.8(1.1), 7.3(1.6),\n7.8(1.8) MeV for the \\Sigma_b^+, \\Sigma_b^-, \\Sigma_b^{*+}, \\Sigma_b^{*-}\ninitial states, respectively. We also derive upper bounds on the widths of the\n\\Xi_b^{\\prime(*)} baryons.",
        "positive": "The Wrong Kind of Gravity: The KPZ formula shows that coupling central charge less than one spin models\nto 2D quantum gravity dresses the conformal weights to get new critical\nexponents, where the relation between the original and dressed weights depends\nonly on the central charge. At the discrete level the coupling to 2D gravity is\neffected by putting the spin models on annealed ensembles of planar random\ngraphs or their dual triangulations, where the connectivity fluctuates on the\nsame time-scale as the spins.\n  Since the sole determining factor in the dressing is the central charge, one\ncould contemplate putting a spin model on a quenched ensemble of 2D gravity\ngraphs with the ``wrong'' central charge. We might then expect to see the\ncritical exponents appropriate to the central charge used in generating the\ngraphs. In such cases the KPZ formula could be interpreted as giving a\ncontinuous line of critical exponents which depend on this central charge. We\nnote that rational exponents other than the KPZ values can be generated using\nthis procedure for the Ising, tricritical Ising and 3-state Potts models."
    },
    {
        "anchor": "The N to $\u0394$ axial transition form factors in quenched and\n  unquenched QCD: The four N to $\\Delta$ axial transition form factors are evaluated using\nquenched QCD, using two flavors of dynamical Wilson fermions and using domain\nwall valence fermions on three-flavor MILC configurations for pion masses down\nto 360 MeV. We provide a prediction for the parity violating asymmetry as a\nfunction of $Q^2$ and examine the validity of the non-diagonal\nGoldberger-Treiman relation.",
        "positive": "Extraction of the bare form factors for the semi-leptonic $B_s$ decays: The computation of the form factors for the $B_s \\to K \\ell \\nu$ decay is\npresented. The b quark is treated by means of Heavy Quark Effective Theory,\ncurrently in the static approximation. In these proceedings we discuss the\nextraction of the bare matrix elements from lattice data through a combined fit\nto two- and three-point correlation functions, as well as by considering\nsuitable ratios. The different methods agree concerning the extracted form\nfactors and approximately 2% accuracy is reached. The non-perturbative\nrenormalization and matching to QCD is described in accompanying proceedings\nPoS(LATTICE2016)292."
    },
    {
        "anchor": "Solving DWF Dirac Equation Using Multi-splitting Preconditioned\n  Conjugate Gradient with Tensor Cores on NVIDIA GPUs: We show that using the multi-splitting algorithm as a preconditioner for the\ndomain wall Dirac linear operator, arising in lattice QCD, effectively reduces\nthe inter-node communication cost, at the expense of performing more on-node\nfloating point and memory operations. Correctly including the boundary\n\\textit{snake} terms, the preconditioner is implemented in the QUDA framework,\nwhere it is found that utilizing kernel fusion and the tensor cores on NVIDIA\nGPUs is necessary to achieve a sufficiently performant preconditioner. A\nreduced-dimension (reduced-$L_s$) strategy is also proposed and tested for the\npreconditioner. We find the method achieves lower time to solution than regular\nCG at high node count despite the additional local computational requirements\nfrom the preconditioner. This method could be useful for supercomputers with\nmore on-node flops and memory bandwidth than inter-node communication\nbandwidth.",
        "positive": "Computation of the electromagnetic pion form factor from lattice QCD in\n  the epsilon regime: We calculate the electromagnetic pion form factor in lattice QCD with 2+1\nflavors of the dynamical overlap quarks. Up and down quark masses are set below\ntheir physical values so that the system is in the so-called epsilon regime\nwith the small size of our lattice ~ 1.8 fm. The finite volume corrections are\ngenerally expected to be ~ 100% in the epsilon regime. We, however, find a way\nto automatically cancel the dominant part of them. Inserting non-zero momenta\nand taking appropriate ratios of the two and three point functions, we can\neliminate the contribution from the zero-momentum pion mode. Then the remaining\nfinite volume effect is a small perturbation from the non-zero modes. Our\nlattice data agree with this theoretical prediction and the extracted pion\ncharge radius is consistent with the experiment."
    },
    {
        "anchor": "Lattice field theory applications in high energy physics: Lattice gauge theory was formulated by Kenneth Wilson in 1974. In the ensuing\ndecades, improvements in actions, algorithms, and computers have enabled\ntremendous progress in QCD, to the point where lattice calculations can yield\nsub-percent level precision for some quantities. Beyond QCD, lattice methods\nare being used to explore possible beyond the standard model (BSM) theories of\ndynamical symmetry breaking and supersymmetry. We survey progress in extracting\ninformation about the parameters of the standard model by confronting lattice\ncalculations with experimental results and searching for evidence of BSM\neffects.",
        "positive": "Is $N=2$ Large?: We study $\\theta$ dependence of the vacuum energy for the 4d SU(2) pure\nYang-Mills theory by lattice numerical simulations. The response of topological\nexcitations to the smearing procedure is investigated in detail, in order to\nextract topological information from smeared gauge configurations. We determine\nthe first two coefficients in the $\\theta$ expansion of the vacuum energy, the\ntopological susceptibility $\\chi$ and the first dimensionless coefficient\n$b_2$, in the continuum limit. We find consistency of the SU(2) results with\nthe large $N$ scaling. By analytic continuing the number of colors, $N$, to\nnon-integer values, we infer the phase diagram of the vacuum structure of SU(N)\ngauge theory as a function of $N$ and $\\theta$. Based on the numerical results,\nwe provide quantitative evidence that 4d SU(2) Yang-Mills theory at $\\theta =\n\\pi$ is gapped with spontaneous breaking of the CP symmetry."
    },
    {
        "anchor": "Lattice Renormalization of Quantum Simulations: With advances in quantum computing, new opportunities arise to tackle\nchallenging calculations in quantum field theory. We show that trotterized\ntime-evolution operators can be related by analytic continuation to the\nEuclidean transfer matrix on an anisotropic lattice. In turn, trotterization\nentails renormalization of the temporal and spatial lattice spacings. Based on\nthe tools of Euclidean lattice field theory, we propose two schemes to\ndetermine Minkowski lattice spacings, using Euclidean data and thereby\novercoming the demands on quantum resources for scale setting. In addition, we\nadvocate using a fixed-anisotropy approach to the continuum to reduce both\ncircuit depth and number of independent simulations. We demonstrate these\nmethods with Qiskit noiseless simulators for a $2+1$D discrete non-Abelian\n$D_4$ gauge theory with two spatial plaquettes.",
        "positive": "Deconfining temperatures in SO(N) and SU(N) gauge theories: We present our current results for the deconfining temperatures in SO(N)\ngauge theories in 2+1 dimensions. SO(2N) theories may help us to understand QCD\nat finite chemical potential since there is a large-N orbifold equivalence\nbetween SO(2N) QCD-like theories and SU(N) QCD, and SO(2N) theories do not have\nthe sign problem present in QCD. We show that the deconfining temperatures in\nthese two theories match at the large-N limit. We also present results for\nSO(2N+1) gauge theories and compare results for SO(6) with SU(4) gauge\ntheories, which have the same Lie algebras but different centres."
    },
    {
        "anchor": "Hadronic Parity Violation from Twisted Mass Lattice QCD: We present results for an exploratory lattice calculation of the leading\nparity-violating pion-nucleon coupling $h_\\pi^1$. Based on the PCAC relation we\nuse a parity-conserving Lagrangian and focus on the techniques to determine the\nnucleon matrix elements of the effective 4-quark operators. For our study we\nemploy an ensemble of twisted mass fermions with $260$ MeV pion mass. Barring\nmixing with lower-dimensional operators and renormalization at this stage, we\ndiscuss our estimate for $h_\\pi^1$.",
        "positive": "Real-time simulation of (2+1)-dimensional lattice gauge theory on qubits: We study the quantum simulation of Z2 lattice gauge theory in 2+1 dimensions.\nThe dual variable formulation, the so-called Wegner duality, is utilized for\nreducing redundant gauge degrees of freedom. The problem of artificial charge\nunconservation is resolved for any charge distribution. As a demonstration, we\nsimulate the real-time evolution of the system with two static electric\ncharges, i.e., with two temporal Wilson lines. Some results obtained by the\nsimulator (with no hardware noise) and the real device (with sizable hardware\nnoise) of a quantum computer are shown."
    },
    {
        "anchor": "Vector spectrum and color screening in two color QCD at nonzero T and\n  \u03bc: We discuss a few aspects of the phase diagram of two color lattice QCD: we\ninvestigate the long distance screening analyzing the behavior of the\ninterquark potential at large distances; we present a first set of results for\nvector mesons and diquarks; we note similarities and differences between\nfeatures at high temperature and high baryon density.",
        "positive": "A model independent determination of $|V_{ub}|$ using the global $q^2$\n  dependence of the dispersive bounds on the $B\\to\u03c0l\u03bd$ form factors: We propose a method to determine the CKM matrix element $|V_{ub}|$ using the\nglobal $q^2$ dependence of the dispersive bound on the form factors for $B\\to\n\\pi l\\nu$ decay. Since the lattice calculation of the $B\\to \\pi l\\nu$ form\nfactor is limited to the large $q^2$ regime, only the experimental data in a\nlimited kinematic range can be used in a conventional method. In our new method\nwhich exploits the statistical distributions of the dispersive bound proposed\nby Lellouch, we can utilize the information of the global $q^2$ dependence for\nall kinematic range. As a feasibility study we determine $|V_{ub}|$ by\ncombining the form factors from quenched lattice QCD, the dispersive bounds,\nand the experimental data by CLEO. We show that the accuracy of $|V_{ub}|$ can\nbe improved by our method."
    },
    {
        "anchor": "A Linux PC cluster for lattice QCD with exact chiral symmetry: A computational system for lattice QCD with exact chiral symmetry is\ndescribed. The platform is a home-made Linux PC cluster, built with\noff-the-shelf components. At present this system constitutes of 64 nodes, with\neach node consisting of one Pentium 4 processor (1.6/2.0/2.5 GHz), one Gbyte of\nPC800/PC1066 RDRAM, one 40/80/120 Gbyte hard disk, and a network card. The\ncomputationally intensive parts of our program are written in SSE2 codes. The\nspeed of this system is estimated to be 70 Gflops, and its price/performance is\nbetter than $1.0/Mflops for 64-bit (double precision) computations in quenched\nQCD. We discuss how to optimize its hardware and software for computing quark\npropagators via the overlap Dirac operator.",
        "positive": "A Parallel Cluster Labeling Method for Monte Carlo Dynamics: We present an algorithm for cluster dynamics to efficiently simulate large\nsystems on MIMD parallel computers with large numbers of processors. The method\ndivides physical space into rectangular cells which are assigned to processors\nand combines a serial local procedure with a nearest neighbor relaxation\nprocess. By controlling overhead and reducing inter-processor communication\nthis method attains good performance and speed-up. The complexity and scaling\nproperties of the algorithm are analyzed.\n  The algorithm has been used to simulate large 2d Ising systems (up to 27808 X\n27808 sites) with Swendsen-Wang dynamics. Typical updating times on the order\nof 82 nanosecs/site and efficiencies larger than 90% have been obtained using\n256 processors on the CM-5 supercomputer."
    },
    {
        "anchor": "An Improved Estimator for the Correlation Function of 2D Nonlinear Sigma\n  Models: I present a new improved estimator for the correlation function of 2D\nnonlinear sigma models. Numerical tests for the 2D XY model and the 2D\nO(3)-invariant vector model were performed. For small physical volume, i.e. a\nlattice size small compared to the to the bulk correlation length, a reduction\nof the statistical error of the finite system correlation length by a factor of\nup to 30 compared to the cluster-improved estimator was observed. This\nimprovement allows for a very accurate determination of the running coupling\nproposed by M. L\"uscher et al. for 2D O(N)-invariant vector models.",
        "positive": "Fluctuations, strangeness and quasi-quarks in heavy-ion collisions from\n  lattice QCD: We report measurements of diagonal susceptibilities for the baryon number,\nchi_B, electrical charge, chi_Q, third component of isospin, chi_I,\nstrangeness, chi_S, and hypercharge, chi_Y, as well as the off-diagonal chi_BQ,\nchi_BY, chi_BS, etc. We show that the ratios of susceptibilities in the high\ntemperature phase are robust variables, independent of lattice spacing, and\ntherefore give predictions for experiments. We also investigate strangeness\nproduction and flavour symmetry breaking matrix elements at finite temperature.\nFinally, we present evidence that in the high temperature phase of QCD the\ndifferent flavour quantum numbers are excited in linkages which are exactly the\nsame as one expects from quarks. We present some investigations of these\nquark-like quasi particles."
    },
    {
        "anchor": "Some properties of B_c from Lattice QCD: We discuss \\(B_c\\) mass (1S state) and decay constant \\(f_{B_c}\\) calculated\nby lattice non-relativistic quantum chromodynamcs(NRQCD) method. In leading\norder of \\(v^2\\), we found that \\(M_{B_c} = 6.33(2)\\) GeV and \\(f_{B_c} =\n395(2)\\) MeV where the error bar is the statistical error only. Using these\nvalues, we estimate QCD effects to leptonic decay width of \\(B_c\\). The decay\nwidth is given by \\(\\Gamma(B_c \\rightarrow l^+\\nu_l) = 0.86(15)m^2_l (1 -\n0.0250(2)m^2_l)^2\\times 10^{-14} ({\\rm GeV})\\), where \\(m_l\\) is in GeV.\nRelativistic correction and \\(\\alpha_s\\) correction to \\(f_{B_c}\\) have also\nbeen considered.",
        "positive": "Effective Polyakov line action from the relative weights method: We apply the relative weights method (arXiv:1209.5697) to determine the\neffective Polyakov line action for SU(2) lattice gauge theory in the confined\nphase, at lattice coupling beta=2.2 and N_t=4 lattice spacings in the time\ndirection. The effective action turns out to be bilinear in the fundamental\nrepresentation Polyakov line variables, with a rather simple expression for the\nfinite range kernel. The validity of this action is tested by computing\nPolyakov line correlators, via Monte Carlo simulation, in both the effective\naction and the underlying lattice theory. It is found that the correlators in\neach theory are in very close agreement."
    },
    {
        "anchor": "Spontaneous breaking of remnant gauge symmetries in zero-temperature\n  SU(2) lattice gauge theory: The 4-d SU(2) lattice gauge theory is simulated in the minimal Coulomb gauge\nwhich aims to maximize the traces of all links in three directions.\nFourth-direction links are interpreted as spins in a Heisenberg-like model with\nvarying interactions. These spins magnetize in 3-d hyperlayers at weak\ncoupling, breaking a remnant gauge symmetry, as well as the Polyakov-loop\nsymmetry. They demagnetize at a phase transition around $\\beta = 2.5$ on the\ninfinite lattice, as determined by Binder cumulant crossings. Because $N$\nsymmetries are breaking on an $N^4$ lattice, the transition is unusually broad,\nencompassing most of the crossover region on typical lattices.",
        "positive": "Filtered overlap: speedup, locality, kernel non-normality and Z_A~1: We investigate the overlap operator with a UV filtered Wilson kernel. The\nfiltering leads to a better localization of the operator even on coarse\nlattices and with the untuned choice $\\rho=1$. Furthermore, the axial-vector\nrenormalization constant $Z_A$ is much closer to 1, reducing the mismatch with\nperturbation theory. We show that all these features persist over a wide range\nof couplings and that the details of filtering prove immaterial. We investigate\nthe properties of the kernel spectrum and find that the kernel non-normality is\nreduced. As a side effect we observe that for certain applications of the\nfiltered overlap a speed-up factor of 2-4 can be achieved."
    },
    {
        "anchor": "Chiral Lattice Gauge Theories from Warped Domain Walls and\n  Ginsparg-Wilson Fermions: We propose a construction of a 2-dimensional lattice chiral gauge theory. The\nconstruction may be viewed as a particular limit of an infinite warped\n3-dimensional theory. We also present a \"single-site'' construction using\nGinsparg-Wilson fermions which may avoid, in both 2 and 4 dimensions, the\nproblems of waveguide-Yukawa models.",
        "positive": "Running coupling of 2-flavor QCD at zero and finite temperature: We present lattice studies of the running coupling in 2-flavor QCD. The\ncoupling at zero temperature (T=0) is extracted from Wilson loops while the\ncoupling at finite temperature ($T\\neq0$) is determined from Polyakov loop\ncorrelation functions."
    },
    {
        "anchor": "Transition in the spectral gap of the massless overlap Dirac operator\n  coupled to abelian fields in three dimensions: The low lying spectrum of the massless overlap Dirac operator coupled to\nabelian fields in three dimensions with three different measures are shown to\nexhibit two phases: a strong coupling gapped phase and a weak coupling gapless\nphase. The vanishing of the gap from the strong coupling side with a Maxwell\nand a conformal measure is governed by a Gaussian exponent. Contrary to this\nresult, the vanishing of the gap from the strong coupling side with a compact\nThirring measure is not consistent with a Gaussian exponent. The low lying\nspectrum with a non-compact Thirring measure does not exhibit a simple\nnon-monotonic behavior as a function of the lattice size on the weak coupling\nside. Our combined analysis suggests exploring the possibility of a strongly\ncoupled continuum theory starting from a compact lattice Thirring model where a\ncompact U(1) gauge field with a single link action is coupled to even number of\nflavors of massless overlap Dirac fermions.",
        "positive": "A New Approach to eta' on the Lattice: We perform an eta' mass analysis based on a total of 1130 dynamical gauge\nfield configurations, with 5 different quark mass values on lattices of size\n16^3*32 (SESAM) and 24^3*40 (TkL) at beta = 5.6. We employ the stochastic\nestimator technique and spectral methods to deal with the disconnected piece of\nthe flavour singlet correlation function. We demonstrate that very early\nplateau formation in the local eta' mass can be achieved by first ground state\nprojecting the connected piece of its correlator."
    },
    {
        "anchor": "Lattice studies of QCD-like theories with many fermionic degrees of\n  freedom: I give an elementary introduction to the study of gauge theories coupled to\nfermions with many degrees of freedom. Besides their intrinsic interest, these\ntheories are candidates for nonperturbative extensions of the Higgs sector of\nthe Standard Model. While related to QCD, these systems can exhibit very\ndifferent behavior from it: they can possess a running gauge coupling with an\ninfrared attractive fixed point (IRFP). I briefly survey recent lattice work in\nthis area.",
        "positive": "From confinement to new states of dense QCD matter: Transitions between centre sectors are related to confinement in pure\nYang-Mills theories. We study the impact of these transitions in QCD-like\ntheories for which centre symmetry is explicitly broken by the presence of\nmatter. For low temperatures, we provide numerical evidence that centre\ntransitions do occur with matter merely providing a bias towards the trivial\ncentre sector until centre symmetry is spontaneously broken at high\ntemperatures. The phenomenological consequences of these transitions for dense\nhadron matter are illustrated in an SU(3) effective quark theory: centre\ndressed quarks undergo condensation due to Bose-type statistics forming a\nhitherto unknown state of dense but cold quark matter."
    },
    {
        "anchor": "On the infrared behavior of Green's functions in Yang-Mills theory: Non-perturbative properties of QCD, such as color confinement, are encoded in\nthe infrared behavior of correlation functions, e.g. propagators and vertices.\nVarious analytic predictions have been suggested for these quantities in\nvarious gauges. Here we numerically test these predictions using lattice gauge\ntheory. In particular, we present results for the 2- and 3-point functions for\nSU(2) Landau-gauge Yang-Mills theory in three and in four dimensions. Special\nattention is paid to systematic finite-volume effects. The gluon and ghost\npropagators are also evaluated in the so-called interpolating gauge (between\nthe Landau and the Coulomb gauge), in order to study their gauge-dependence.\nFinally, we consider these propagators in Landau gauge at finite temperature,\nwith the aim of understanding the effect of the deconfinement phase transition\non their infrared behavior. All our results are compatible with the so-called\nGribov-Zwanziger confinement scenario.",
        "positive": "Determination of the continuous $\u03b2$ function of SU(3) Yang-Mills\n  theory: In infinite volume the gradient flow transformation can be interpreted as a\ncontinuous real-space Wilsonian renormalization group (RG) transformation. This\napproach allows one to determine the continuous RG $\\beta$ function, an\nalternative to the finite-volume step-scaling function. Unlike step-scaling,\nwhere the lattice must provide the only scale, the continuous $\\beta$ function\ncan be used even in the confining regime where dimensional transmutation\ngenerates a physical scale $\\Lambda_{\\mathrm{QCD}}$. We investigate a pure\ngauge SU(3) Yang-Mills theory both in the deconfined and the confined phases\nand determine the continuous $\\beta$ function in both. Our investigation is\nbased on simulations done with the tree-level Symanzik gauge action on lattice\nvolumes up to $32^4$ using both Wilson and Zeuthen gradient flow (GF)\nmeasurements. Our continuum GF $\\beta$ function exhibits considerably slower\nrunning than the universal 2-loop perturbative prediction, and at strong\ncouplings it runs even slower than the 1-loop prediction."
    },
    {
        "anchor": "Symmetries of spatial meson correlators in high temperature QCD: Based on a complete set of $J = 0$ and $J=1$ spatial isovector correlation\nfunctions calculated with $N_F = 2$ domain wall fermions we identify an\nintermediate temperature regime of $T \\sim 220 - 500$ MeV ($1.2T_c$--$2.8T_c$),\nwhere chiral symmetry is restored but the correlators are not yet compatible\nwith a simple free quark behavior. More specifically, in the temperature range\n$T \\sim 220 - 500$ MeV we identify a multiplet structure of spatial correlators\nthat suggests emergent $SU(2)_{CS}$ and $SU(4)$ symmetries, which are not\nsymmetries of the free Dirac action. The symmetry breaking effects in this\ntemperature range are less than 5%. Our results indicate that at these\ntemperatures the chromo-magnetic interaction is suppressed and the elementary\ndegrees of freedom are chirally symmetric quarks bound into color-singlet\nobjects by the chromo-electric component of the gluon field. At temperatures\nbetween 500 and 660 MeV the emergent $SU(2)_{CS}$ and $SU(4)$ symmetries\ndisappear and one observes a smooth transition to the regime above $T \\sim 1$\nGeV where only chiral symmetries survive, which are finally compatible with\nquasi-free quarks.",
        "positive": "Laplacian Center Vortices: I present a unified picture of center vortices and Abelian monopoles. Both\nappear as local gauge ambiguities in the Laplacian Center Gauge. This gauge is\nconstructed for a general SU(N) theory. Numerical evidence is presented, for\nSU(2) and SU(3), that the projected $Z_N$ theory confines with a string tension\nsimilar to the non-Abelian one."
    },
    {
        "anchor": "Local Chirality of Low-Lying Dirac Eigenmodes and the Instanton Liquid\n  Model: The reasons for using low-lying Dirac eigenmodes to probe the local structure\nof topological charge fluctuations in QCD are discussed, and it is pointed out\nthat the qualitative double-peaked behavior of the local chiral orientation\nprobability distribution in these modes is necessary, but not sufficient for\ndominance of instanton-like fluctuations. The results with overlap Dirac\noperator in Wilson gauge backgrounds at lattice spacings ranging from a~0.04 fm\nto a~0.12 fm are reported, and it is found that the size and density of local\nstructures responsible for double-peaking of the distribution are in\ndisagreement with the assumptions of the Instanton Liquid Model. More\ngenerally, our results suggest that vacuum fluctuations of topological charge\nare not effectively dominated by locally quantized (integer-valued) lumps in\nQCD.",
        "positive": "Improvements of the local bosonic algorithm: We report on several improvements of the local bosonic algorithm proposed by\nM. Luescher. We find that preconditioning and over-relaxation works very well.\nA detailed comparison between the bosonic and the Kramers-algorithms shows\ncomparable performance for the physical situation examined."
    },
    {
        "anchor": "Spins coupled to a $Z_2$-Regge lattice in 4d: We study an Ising spin system coupled to a fluctuating four-dimensional\n$Z_2$-Regge lattice and compare with the results of the four-dimensional Ising\nmodel on a regular lattice. Particular emphasis is placed on the phase\ntransition of the spin system and the associated critical exponents. We present\nresults from finite-size scaling analyses of extensive Monte Carlo simulations\nwhich are consistent with mean-field predictions.",
        "positive": "Canonical partition function and center symmetry breaking in finite\n  density lattice gauge theories: We study the nature of the phase transition of lattice gauge theories at high\ntemperature and high density by focusing on the probability distribution\nfunction, which represents the probability that a certain density will be\nrealized in a heat bath. The probability distribution function is obtained by\ncreating a canonical partition function fixing the number of particles from the\ngrand partition function. However, if the Z_3 center symmetry, which is\nimportant for understanding the finite temperature phase transition of SU(3)\nlattice gauge theory, is maintained on a finite lattice, the probability\ndistribution function is always zero, except when the number of particles is a\nmultiple of 3. For U(1) lattice gauge theory, this problem is more serious. The\nprobability distribution becomes zero when the particle number is nonzero. This\nproblem is essentially the same as the problem that the expectation value of\nthe Polyakov loop is always zero when calculating with finite volume. In this\nstudy, we propose a solution to this problem. We also propose a method to avoid\nthe sign problem, which is an important problem at finite density, using the\ncenter symmetry. In the case of U(1) lattice gauge theory with heavy fermions,\nnumerical simulations are actually performed, and we demonstrate that the\nprobability distribution function at a finite density can be calculated by the\nmethod proposed in this study. Furthermore, the application of this method to\nQCD is discussed."
    },
    {
        "anchor": "Cluster Percolation in O(n) Spin Models: The spontaneous symmetry breaking in the Ising model can be equivalently\ndescribed in terms of percolation of Wolff clusters. In O(n) spin models\nsimilar clusters can be built in a general way, and they are currently used to\nupdate these systems in Monte Carlo simulations. We show that for 3-dimensional\nO(2), O(3) and O(4) such clusters are indeed the physical `islands' of the\nsystems, i.e., they percolate at the physical threshold and the percolation\nexponents are in the universality class of the corresponding model. For O(2)\nand O(3) the result is proven analytically, for O(4) we derived it by numerical\nsimulations.",
        "positive": "Numerical study of unitary fermions in one spatial dimension: I perform lattice Monte Carlo studies of universal four-component fermion\nsystems in one spatial dimension. Continuum few-body observables (i.e.,\nground-state energies and integrated contact densities) are determined for both\nunpolarized and polarized systems of up to eight fermions confined to a\nharmonic trap. Estimates of the continuum energies for four and five trapped\nfermions show agreement with exact analytic calculations to within\napproximately one percent statistical uncertainties. Continuum many-body\nobservables are determined for unpolarized systems of up to 88 fermions\nconfined to a finite box, and 56 fermions confined to a harmonic trap. Results\nare reported for universal quantities such as the Bertsch parameter, defined as\nthe energy of the untrapped many-body system in units of the corresponding\nfree-gas energy, and its subleading correction at large but finite scattering\nlength. Two independent estimates of these quantities are obtained from\nthermodynamic limit extrapolations of continuum extrapolated observables. A\nthird estimate of the Bertsch parameter is obtained by combining estimates of\nthe untrapped and trapped integrated contact densities with additional\ntheoretical input from a calculation based on Thomas-Fermi theory. All\nestimates of the Bertsch parameter and its subleading correction are found to\nbe consistent to within approximately one percent statistical uncertainties.\nFinally, the continuum restoration of virial theorems is verified for both few-\nand many-body systems confined to a trap."
    },
    {
        "anchor": "Non-perturbative renormalization of the quark condensate in\n  Ginsparg-Wilson regularizations: We present a method to compute non-perturbatively the renormalization\nconstant of the scalar density for Ginsparg-Wilson fermions. It relies on\nchiral symmetry and is based on a matching of renormalization group invariant\nmasses at fixed pseudoscalar meson mass, making use of results previously\nobtained by the ALPHA Collaboration for O(a)-improved Wilson fermions. Our\napproach is quite general and enables the renormalization of scalar and\npseudoscalar densities in lattice regularizations that preserve chiral symmetry\nand of fermion masses in any regularization. As an application we compute the\nnon-perturbative factor which relates the renormalization group invariant quark\ncondensate to its bare counterpart, obtained with overlap fermions at beta=5.85\nin the quenched approximation.",
        "positive": "Hagedorn spectrum and equation of state of Yang-Mills theories: We present a novel lattice calculation of the equation of state of SU(2)\nYang-Mills theory in the confining phase. We show that a gas of massive,\nnon-interacting glueballs describes remarkably well the results, provided that\na bosonic closed-string model is used to derive an exponentially growing\nHagedorn spectrum for the heavy glueball states with no free parameters. This\neffective model can be applied to SU(3) Yang-Mills theory and the theoretical\nprediction agrees nicely with the lattice results reported by Bors\\'anyi et al.\nin JHEP 07 (2012) 056."
    },
    {
        "anchor": "Colour confinement as dual Meissner effect: $SU(2)$ gauge theory: We demonstrate that confinement in $SU(2)$ gauge theory is produced by dual\nsuperconductivity of the vacuum. We show that for $T < T_c$ (temperature of\ndeconfining phase transition) the $U(1)$ symmetry related to monopole charge\nconservation is spontaneously broken; for $T > T_c$ the symmetry is restored.",
        "positive": "Scaling properties of the chiral phase transition in the low density\n  region of two-flavor QCD with improved Wilson fermions: We study scaling behavior of a chiral order parameter in the low density\nregion, performing a simulation of two-flavor QCD with improved Wilson quarks.\nThe scaling behavior of the chiral order parameter defined by a Ward-Takahashi\nidentity agrees with the scaling function of the three-dimensional O(4) spin\nmodel at zero chemical potential. We extend the scaling study to finite density\nQCD. Applying the reweighting method and calculating derivatives of the chiral\norder parameter with respect to the chemical potential, the scaling properties\nof the chiral phase transition are discussed in the low density region. We\nmoreover calculate the curvature of the phase boundary of the chiral phase\ntransition in the temperature and chemical potential plane assuming the O(4)\nscaling relation."
    },
    {
        "anchor": "Comments on staggered fermions / Panel discussion: The rooting procedure commonly used with staggered fermions does not\ncorrectly treat non-perturbative effects associated with gauge field topology.\nIn practice these effects are small for the physics of flavor non-singlet\nparticles. However large uncontrolled systematic errors are expected for flavor\nsinglet issues, such as the mass of the eta prime meson. While the relative\nspeed of the algorithm in large scale simulations may justify its use, the\nmethod is an approximation and should not be promoted as a first principles\napproach to the strong interactions.",
        "positive": "Messages for QCD from the Superworld: Recent discoveries in supersymmetric gauge theories have significant\nimplications for our understanding for QCD and of field theory in general. The\nphases of N=1 supersymmetric QCD (SQCD) are discussed, and the possibility of\nsimilar phases in non-supersymmetric QCD is emphasized. It is described how\nduality in SQCD links many previously known duality transformations that were\nthought to be distinct, including Olive-Montonen duality of N=4 supersymmetric\ngauge theory and quark-hadron duality in (S)QCD. A link between Olive-Montonen\nduality and the confining strings of (S)QCD is explained, in which a picture of\nconfinement via non-abelian monopole condensation --- a generalized dual\nMeissner effect --- emerges explicitly. In this picture, unlike previous ones,\nthe confining flux tubes carry the correct Z_N discrete charges. A number of\nstudies of these subjects, which could be carried out using lattice gauge\ntheory, are proposed."
    },
    {
        "anchor": "Topological susceptibility and $\u03b7'$ meson mass from $N_f=2$ lattice\n  QCD at the physical point: In this paper we explore the computation of topological susceptibility and\n$\\eta'$ meson mass in $N_f=2$ flavor QCD using lattice techniques with physical\nvalue of the pion mass as well as larger pion mass values. We observe that the\nphysical point can be reached without a significant increase in the statistical\nnoise. The mass of the $\\eta'$ meson can be obtained from both fermionic two\npoint functions and topological charge density correlation functions, giving\ncompatible results. With the pion mass dependence of the $\\eta'$ mass being\nflat we arrive at $M_{\\eta'}= 772(18)\\ \\mathrm{MeV}$ without an explicit\ncontinuum limit. For the topological susceptibility we observe a linear\ndependence on $M_\\pi^2$, however, with an additional constant stemming from\nlattice artifacts.",
        "positive": "Pion magnetic polarisability using the background field method: The magnetic polarisability is a fundamental property of hadrons, which\nprovides insight into their structure in the low-energy regime. The pion\nmagnetic polarisability is calculated using lattice QCD in the presence of\nbackground magnetic fields. The results presented are facilitated by the\nintroduction of a new magnetic-field dependent quark-propagator eigenmode\nprojector and the use of the background-field corrected clover fermion action.\nThe magnetic polarisabilities are calculated in a relativistic formalism, and\nthe excellent signal-to-noise property of pion correlation functions\nfacilitates precise values."
    },
    {
        "anchor": "Quasiparticle properties of nonequilibrium gluon plasma: We apply classical gluodynamics to early stages of ultrarelativistic\nheavy-ion collisions. We start by going through the space-time evolution of\nultrarelativistic heavy-ion collisions in the color glass condensate framework\nand the basics of real-time gluodynamics on the lattice in the temporal gauge.\n  We study the plasmon mass scale in three- and two-dimensional systems by\ncomparing three different methods to measure the mass scale. The methods are a\nformula which can be derived from Hard Thermal Loop effective theory at leading\norder (HTL), the effective dispersion relation (DR) and measurement of the\nplasma oscillation frequency triggered by the introduction of a uniform\nelectric field (UE) into the system. We observe that in both systems the\nplasmon mass scale decreases like a power law after an occupation number\ndependent initial transient time. In both cases the UE and HTL methods are in\nrough agreement, and in the three-dimensional case the two agree in the\ncontinuum limit.\n  As a second way to study the quasiparticle properties, we derive, implement\nand test an algorithm which can be used to simulate linearized fluctuations on\ntop of the classical background. The algorithm is derived by requiring\nconservation of Gauss' law and gauge invariance. We then apply the algorithm to\nspectral properties of overoccupied gluodynamics using linear response theory.\nWe establish the existence of transverse and longitudinal quasiparticles by\nextracting their spectral functions. We also extract the dispersion relation,\neffective mass, plasmon mass and damping rate of the quasiparticles. Our\nresults are consistent with the HTL effective theory, but we also observe\neffects beyond leading order HTL.",
        "positive": "Nucleon Transversity Distribution at the Physical Pion Mass from Lattice\n  QCD: We report a state-of-the-art lattice calculation of the isovector quark\ntransversity distribution of the proton at the physical pion mass. Within the\nframework of large-momentum effective theory (LaMET), we compute the\ntransversity quasi-distributions using clover valence fermions on 2+1+1-flavor\n(up/down, strange, charm) HISQ-lattice configurations with boosted proton\nmomenta as large as 3.0~GeV. The relevant lattice matrix elements are\nnonperturbatively renormalized in regularization-independent\nmomentum-subtraction (RI/MOM) scheme and systematically matched to the physical\ntransversity distribution. With high statistics, large proton momenta and\nmeticulous control of excited-state contamination, we provide the best\ntheoretical prediction for the large-$x$ isovector quark transversity\ndistribution, with better precision than the most recent global analyses of\nexperimental data. Our result also shows that the sea quark asymmetry in the\nproton transversity distribution is consistent with zero, which has been\nassumed in all current global analyses."
    },
    {
        "anchor": "Effective Polyakov line action from strong lattice couplings to the\n  deconfinement transition: We calculate the effective Polyakov line action corresponding to SU(2)\nlattice gauge theory on a 16^3 X 4 lattice via the \"relative weights\" method.\nWe consider a variety of lattice couplings, ranging from beta=1.2 in the\nstrong-coupling domain, to beta=2.3 at the deconfinement transition, in order\nto study how the effective action evolves with beta. Comparison of Polyakov\nline correlators computed in the effective theory and the underlying gauge\ntheory is used to test the validity of the effective action for beta > 1.4,\nwhile for beta=1.2, 1.4 we can compare our effective action to the one obtained\nfrom a low-order strong-coupling expansion. Very good agreement is found at all\ncouplings. We find that the effective action is given by a simple expression\nbilinear in the Polyakov lines. The range of the bilinear term, away from\nstrong coupling, grows rapidly in lattice units as beta increases.",
        "positive": "A toy model test of a new algorithm for bozonization of fermion\n  determinants: Different aspects of bozonization algorithm proposed by Slavnov are tested by\nnumerical simulations of a one dimensional toy model."
    },
    {
        "anchor": "Strong isospin breaking with twisted mass lattice QCD: In this work we propose a method for including strong isospin breaking in\ntwisted mass lattice calculations, while preserving flavor identification. We\nutilize a partially quenched construction in which the sea quarks are given by\nthe standard twisted mass lattice action while the valence quarks have an\nadditional strong isospin breaking mass term. This construction allows for a\npractical use with existing twisted-mass gauge ensembles. Additionally, we\nconstruct the relevant partially quenched twisted mass chiral perturbation\ntheory for both mesons and baryons to O(m_q^2, m_q a, a^2). We provide explicit\nexpressions for the pion, nucleon and delta masses, as well as the\ncorresponding mass splittings, and discuss the resulting errors from including\nthe strong isospin breaking in the valence sector only. Finally, we demonstrate\nhow the application of this idea can be used, with mild approximations, to\ndetermine the values of both the up and down quark masses.",
        "positive": "Precision Study of Excited State Effects in Nucleon Matrix Elements: We present a dedicated analysis of the influence of excited states on the\ncalculation of nucleon matrix elements. This calculation is performed at a\nfixed value of the lattice spacing, volume and pion mass that are typical of\ncontemporary lattice computations. We focus on the nucleon axial charge, g_A,\nfor which we use about 7,500 measurements, and on the average momentum of the\nunpolarized isovector parton distribution, <x>_{u-d}, for which we use about\n23,000 measurements. All computations are done employing N_f=2+1+1\nmaximally-twisted-mass Wilson fermions and using non-perturbatively calculated\nrenormalization factors. Excited state effects are shown to be negligible for\ng_A whereas they lead to an O(10%) downward shift for <x>_{u-d}."
    },
    {
        "anchor": "Monte Carlo Study of Cluster-Diameter Distribution: A New Observable to\n  Estimate Correlation Lengths: We report numerical simulations of two-dimensional $q$-state Potts models\nwith emphasis on a new quantity for the computation of spatial correlation\nlengths. This quantity is the cluster-diameter distribution function\n$G_{diam}(x)$, which measures the distribution of the diameter of\nstochastically defined cluster. Theoretically it is predicted to fall off\nexponentially for large diameter $x$, $G_{diam} \\propto \\exp(-x/\\xi)$, where\n$\\xi$ is the correlation length as usually defined through the large-distance\nbehavior of two-point correlation functions. The results of our extensive Monte\nCarlo study in the disordered phase of the models with $q=10$, 15, and $20$ on\nlarge square lattices of size $300 \\times 300$, $120 \\times 120$, and $80\n\\times 80$, respectively, clearly confirm the theoretically predicted behavior.\nMoreover, using this observable we are able to verify an exact formula for the\ncorrelation length $\\xi_d(\\beta_t)$ in the disordered phase at the first-order\ntransition point $\\beta_t$ with an accuracy of about $1%-2%$ for all considered\nvalues of $q$. This is a considerable improvement over estimates derived from\nthe large-distance behavior of standard (projected) two-point correlation\nfunctions, which are also discussed for comparison.",
        "positive": "The nucleon to Delta electromagnetic transition form factors in lattice\n  QCD: The electromagnetic nucleon to Delta transition form factors are evaluated\nusing two degenerate flavors of dynamical Wilson fermions and using dynamical\nsea staggered fermions with domain wall valence quarks. The two subdominant\nquadrupole form factors are evaluated for the first time in full QCD to\nsufficient accuracy to exclude a zero value, which is taken as a signal for\ndeformation in the nucleon-Delta system. For the Coulomb quadrupole form factor\nthe unquenched results show deviations from the quenched results at low q^2\nbringing dynamical lattice results closer to experiment, thereby confirming the\nimportance of pion cloud contributions on this quantity."
    },
    {
        "anchor": "The Low-lying Dirac Eigenmodes from Domain Wall Fermions: We calculate the low-lying eigenvalues and eigenvectors of the hermitian\ndomain wall Dirac operator on various gauge backgrounds by Ritz minimization.\nThe mass dependence of these eigenvalues is studied to extract the physical 4\ndimensional $\\lambda$, whose spectral density is related to $<\\bar{\\psi} \\psi>$\nthrough the Banks-Casher relation, and $\\delta m$, which represents the effects\nof the residual chiral symmetry breaking in domain wall formalism on a per\neigenmode basis. The topological structure of the underlying gauge field is\nexamined by measuring the $\\Gamma_5$ matrix elements between the low-lying\neigenmodes.",
        "positive": "Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: The\n  $\u03c1$-resonance: We present an investigation of the Rho-meson from Nf=2+1+1 flavour lattice\nQCD. The calculation is performed based on gauge configuration ensembles\nproduced by the ETM collaboration with three lattice spacing values and pion\nmasses ranging from 230 MeV to 500 MeV. Applying the L\\\"uscher method phase\nshift curves are determined for all ensembles separately. Assuming a\nBreit-Wigner form, the Rho-meson mass and width are determined by a fit to\nthese phase shift curves. Mass and width combined are then extrapolated to the\nchiral limit, while lattice artefacts are not detectable within our statistical\nuncertainties. For the Rho-meson mass extrapolated to the physical point we\nfind good agreement with experiment. The corresponding decay width differs by\nabout two standard deviations from the experimental value."
    },
    {
        "anchor": "Monte Carlo Algorithms For Reduced Lattices, Mixed Actions, And\n  Double-Trace Deformations: We construct efficient Monte Carlo updating algorithms for two classes of\npure SU(N) lattice gauge actions with non-linear dependence on the link\nvariables. Our construction generalises the method of auxiliary variables used\nby Fabricius and Haan in the framework of Eguchi-Kawai models. We first review\nthe original Fabricius-Haan method of constructing a pseudo-heatbath algorithm\nfor fully reduced models, and discuss its extension to lattices with any number\nof reduced directions. We then use a similar method to construct updating\nalgorithms for generic SU(N) mixed Wilson actions. We construct explicit\nexamples of algorithms for Wilson actions whose plaquettes are in an\nirreducible representation of SU(N) with N-ality up to 3. We also construct\nupdating algorithms for the lattice version of centre-stabilised SU(N)\nYang-Mills theories defined on R^{d-1} x S^1, including the case of a fully\nreduced compact direction. We simulate the new algorithms and show that they\nare, in general, significantly more efficient than their Metropolis\ncounterparts.",
        "positive": "Monte Carlo Simulations of Higgs-Fermion Systems: To gain understanding of the Higgs-fermion sector of the standard model, we\nstudy the one-component $Z_2$ symmetric and the four-component O(4) symmetric\nscalar models coupled to staggered fermions using the hybrid Monte Carlo\nalgorithm. We map out the phase diagrams, and show that the $Z_2$ model has a\ntree level perturbative behaviour at all points in the broken phase. The O(4)\nmodel on the other hand is shown to have two characteristically different\nbehaviours; one for large Yukawa couplings where the fermions get infinitely\nheavy and decouple in the continuum limit, and one for small Yukawa couplings\nwhere the fermions remain light. For very small Yukawa couplings the fermions\nshow the expected tree level perturbative behaviour and for larger values the\ninfluence of the fermions becomes substantial. After estimating the finite size\neffects at small Yukawa couplings we make relatively accurate measurements of\nthe scalar mass and wave function renormalization constants at the point\n$\\kappa=0.0$ and $y=0.85-0.95$. Even though this is not the largest value\npossible for the Yukawa coupling we are able to show that the bound of the\nHiggs mass will move up significantly, from around $600 GeV$ to around $900\nGeV$, by including fermions in the model. Likewise we show that a bound can be\nput on the fermion mass, around $200 GeV$. The largest value of the bare Yukawa\ncoupling is obtained at rather large negative $\\kappa$. Due to bad convergence\nrates in the inversion of the fermion matrix, which is needed in the updating\nprocedure, this region has not been possible to investigate."
    },
    {
        "anchor": "The Monotony Criterion for A Finite Size Scaling Analysis of Phase\n  Transitions: We propose a new criterion to analyse the order of phase transitions within a\nfinite size scaling analysis. It refers to response functions like order\nparameter susceptibilities and the specific heat and states different monotony\nbehaviour in volume for first and second order transitions close to the\ntransition point. The criterion applies to analytical and numerical studies of\nphase diagrams including tricritical behaviour.",
        "positive": "Quantum State Preparation for the Schwinger Model: It is not possible, using standard lattice techniques in Euclidean space, to\ncalculate the complete fermionic spectrum of a quantum field theory. Algorithms\nrunning on quantum computers have the potential to access the theory with\nreal-time evolution, enabling a direct computation. As a testing ground we\nconsider the 1 + 1-dimensional Schwinger model with the presence of a {\\theta}\nterm using a staggered fermions discretization. We study the convergence\nproperties of two different algorithms - adiabatic evolution and the Quantum\nApproximate Optimization Algorithm - with an emphasis on their cost in terms of\nCNOT gates. This is crucial to understand the feasibility of these algorithms,\nbecause calculations on near-term quantum devices depend on their rapid\nconvergence. We also propose a blocked algorithm that has the first indications\nof a better scaling behavior with the dimensionality of the problem."
    },
    {
        "anchor": "Chebyshev and Backus-Gilbert reconstruction for inclusive semileptonic\n  $B_{(s)}$-meson decays from Lattice QCD: We present a study on the nonperturbative calculation of observables for\ninclusive semileptonic decays of $B_{(s)}$ mesons using lattice QCD. We focus\non the comparison of two different methods to analyse the lattice data of\nEuclidean correlation functions, specifically Chebyshev and Backus-Gilbert\napproaches. This type of computation may eventually provide new insight into\nthe long-standing tension between the inclusive and exclusive determinations of\nthe Cabibbo-Kobayashi-Maskawa (CKM) matrix elements $|V_{cb}|$ and $|V_{ub}|$.\nWe report the results from a pilot lattice computation for the decay $B_s\n\\rightarrow X_c \\, l\\nu_l$, where the valence quark masses are approximately\ntuned to their physical values using the relativistic-heavy quark action for\nthe $b$ quark and the domain-wall formalism for the other valence quarks. We\naddress the computation of the total decay rate as well as leptonic and\nhadronic moments, discussing similarities and differences between the two\nanalysis techniques.",
        "positive": "An adaptive aggregation based domain decomposition multilevel method for\n  the lattice wilson dirac operator: multilevel results: In lattice QCD computations a substantial amount of work is spent in solving\nlinear systems arising in Wilson's discretization of the Dirac equations. We\nshow first numerical results of the extension of the two-level DD-\\alpha AMG\nmethod to a true multilevel method based on our parallel MPI-C implementation.\nUsing additional levels pays off, allowing to cut down the core minutes spent\non one system solve by a factor of approximately 700 compared to standard\nKrylov subspace methods and yielding another speed-up of a factor of 1.7 over\nthe two-level approach."
    },
    {
        "anchor": "Classifying topological sector via machine learning: We employ a machine learning technique for an estimate of the topological\ncharge $Q$ of gauge configurations in SU(3) Yang-Mills theory in vacuum. As a\nfirst trial, we feed the four-dimensional topological charge density with and\nwithout smoothing into the convolutional neural network and train it to\nestimate the value of $Q$. We find that the trained neural network can estimate\nthe value of $Q$ from the topological charge density at small flow time with\nhigh accuracy. Next, we perform the dimensional reduction of the input data as\na preprocessing and analyze lower dimensional data by the neural network. We\nfind that the accuracy of the neural network does not have\nstatistically-significant dependence on the dimension of the input data. From\nthis result we argue that the neural network does not find characteristic\nfeatures responsible for the determination of $Q$ in the higher dimensional\nspace.",
        "positive": "Real-time scattering in the lattice Schwinger model: Tensor network methods have demonstrated their suitability for the study of\nequilibrium properties of lattice gauge theories, even close to the continuum\nlimit. We use them in an out-of-equilibrium scenario, much less explored so\nfar, by simulating the real-time collisions of composite mesons in the lattice\nSchwinger model. Constructing wave-packets of vector mesons at different\nincoming momenta, we observe the opening of the inelastic channel in which two\nheavier mesons are produced and identify the momentum threshold. To detect the\nproducts of the collision in the strong coupling regime we propose local\nquantitites that could be measured in current quantum simulation platforms."
    },
    {
        "anchor": "Chiral Condensate in the Deconfined Phase of Quenched Gauge Theories: We compute the low lying spectrum of the overlap Dirac operator in the\ndeconfined phase of finite-temperature quenched gauge theory. It suggests the\nexistence of a chiral condensate which we confirm with a direct stochastic\nestimate. We show that the part of the spectrum responsible for the chiral\ncondensate can be understood as arising from a dilute gas of instantons and\nanti-instantons.",
        "positive": "Potts Models on Feynman Diagrams: We investigate numerically and analytically Potts models on ``thin'' random\ngraphs -- generic Feynman diagrams, using the idea that such models may be\nexpressed as the N --> 1 limit of a matrix model. The thin random graphs in\nthis limit are locally tree-like, in distinction to the ``fat'' random graphs\nthat appear in the planar Feynman diagram limit, more familiar from discretized\nmodels of two dimensional gravity.\n  The interest of the thin graphs is that they give mean field theory behaviour\nfor spin models living on them without infinite range interactions or the\nboundary problems of genuine tree-like structures such as the Bethe lattice.\nq-state Potts models display a first order transition in the mean field for\nq>2, so the thin graph Potts models provide a useful test case for exploring\ndiscontinuous transitions in mean field theories in which many quantities can\nbe calculated explicitly in the saddle point approximation."
    },
    {
        "anchor": "The b-quark mass from non-perturbative $N_f=2$ Heavy Quark Effective\n  Theory at $O(1/m_h)$: We report our final estimate of the b-quark mass from $N_f=2$ lattice QCD\nsimulations using Heavy Quark Effective Theory non-perturbatively matched to\nQCD at $O(1/m_h)$. Treating systematic and statistical errors in a conservative\nmanner, we obtain $\\overline{m}_{\\rm b}^{\\overline{\\rm MS}}(2 {\\rm\nGeV})=4.88(15)$ GeV after an extrapolation to the physical point.",
        "positive": "Remarks on the reweighting method in the chemical potential direction: We comment on the reweighting method in the chemical potential $(\\mu_{\\rm\nq})$ direction. We study the fluctuation of the reweighting factor during\nMonte-Carlo steps. We find that it is the absolute value of the reweighting\nfactor that mainly contributes to the shift of the phase transition line\n$(\\beta_c)$ by the presence of $\\mu_{\\rm q}$. The phase fluctuation is a cause\nof the sign problem, but the effect on $\\beta_c$ seems to be small. We also\ndiscuss $\\beta_c$ for Iso-vector chemical potential and $\\beta_c$ determined\nfrom simulations with imaginary chemical potential."
    },
    {
        "anchor": "Anomalous Chiral Symmetry Breaking above the QCD Phase Transition: We study the anomalous breaking of U_A(1) symmetry just above the QCD phase\ntransition for zero and two flavors of quarks, using a staggered fermion,\nlattice discretization. The properties of the QCD phase transition are expected\nto depend on the degree of U_A(1) symmetry breaking in the transition region.\nFor the physical case of two flavors, we carry out extensive simulations on a\n16^3 x 4 lattice, measuring a difference in susceptibilities which is sensitive\nto U_A(1) symmetry and which avoids many of the staggered fermion\ndiscretization difficulties. The results suggest that anomalous effects are at\nor below the 15% level.",
        "positive": "Using NSPT for the Removal of Hypercubic Lattice Artifacts: The treatment of hypercubic lattice artifacts is essential for the\ncalculation of non-perturbative renormalization constants of RI-MOM schemes. It\nhas been shown that for the RI'-MOM scheme a large part of these artifacts can\nbe calculated and subtracted with the help of diagrammatic Lattice Perturbation\nTheory (LPT). Such calculations are typically restricted to 1-loop order, but\none may overcome this limitation and calculate hypercubic corrections for any\noperator and action beyond the 1-loop order using Numerical Stochastic\nPerturbation Theory (NSPT). In this study, we explore the practicability of\nsuch an approach and consider, as a first test, the case of Wilson fermion\nbilinear operators in a quenched theory. Our results allow us to compare\nboosted and unboosted perturbative corrections up to the 3-loop order."
    },
    {
        "anchor": "On finite volume effects in the chiral extrapolation of baryon masses: We perform an analysis of the QCD lattice data on the baryon octet and\ndecuplet masses based on the relativistic chiral Lagrangian. The baryon self\nenergies are computed in a finite volume at next-to-next-to-next-to leading\norder (N$^3$LO), where the dependence on the physical meson and baryon masses\nis kept. The number of free parameters is reduced significantly down to 12 by\nrelying on large-$N_c$ sum rules. Altogether we describe accurately more than\n220 data points from six different lattice groups, BMW, PACS-CS, HSC, LHPC,\nQCDSF-UKQCD and NPLQCD. Values for all counter terms relevant at N$^3$LO are\npredicted. In particular we extract a pion-nucleon sigma term of 39$_{-1}^{+2}$\nMeV and a strangeness sigma term of the nucleon of $\\sigma_{sN} = 84^{+\n28}_{-\\;4}$ MeV. The flavour SU(3) chiral limit of the baryon octet and\ndecuplet masses is determined with $(802 \\pm 4)$ MeV and $(1103 \\pm 6)$ MeV.\nDetailed predictions for the baryon masses as currently evaluated by the ETM\nlattice QCD group are made.",
        "positive": "Quark Mass Dependence of the QCD Critical End Point in the Strong\n  Coupling Limit: Strong coupling lattice QCD in the dual representation allows to study the\nfull $\\mu$-$T$ phase diagram, due to the mildness of the finite density sign\nproblem. Such simulations have been performed in the chiral limit, both at\nfinite $N_t$ and in the continuous time limit. Here we extend the phase diagram\nto finite quark masses, with an emphasis on the low temperature first order\ntransition. We present our results on the quark mass dependence of the critical\nend point and the first order line obtained by Monte Carlo via the worm\nalgorithm."
    },
    {
        "anchor": "Extraction of hadron-hadron potentials on the lattice within 2+1\n  dimensional QED: A potential between mesons is extracted from 4-point functions within lattice\ngauge theory taking 2+1 dimensional QED as an example. This theory possesses\nconfinement and dynamical fermions. The resulting meson-meson potential has a\nshort-ranged hard repulsive core due to antisymmetrization. The expected\ndipole-dipole forces lead to attraction at intermediate distances. Sea quarks\nlead to a softer form of the total potential.",
        "positive": "Deconfinement transition in two-flavour lattice QCD with dynamical\n  overlap fermions in an external magnetic field: We study the influence of an external magnetic field on the deconfinement\ntransition in two-flavour lattice QCD with physical quark charges. We use\ndynamical overlap fermions without any approximation such as fixed topology and\nperform simulations on a $16^3 \\times 6$ lattice and at a pion mass around\n$500MeV$. The pion mass (as well as the lattice spacing) was determined in\nindependent runs on $12^3 \\times 24$ lattices. We consider two temperatures,\none of which is close to the deconfinement transition and one which is above.\nWithin our limited statistics the dependence of the Polyakov loop and chiral\ncondensate on the magnetic field supports the \"inverse magnetic catalysis\"\nscenario in which the transition temperature decreases as the field strength\ngrows for temperature not to far above the critical temperature."
    },
    {
        "anchor": "Nucleon observables and axial charges of other baryons using twisted\n  mass fermions: We present results on the nucleon scalar, axial and tensor charges, as well\nas, on the first moments of the unpolarized, polarized and transversity parton\ndistributions using $N_f=2$ and $N_f=2+1+1$ twisted mass fermions. These\ninclude an ensemble that yields the physical value of the ratio of the nucleon\nto the pion mass. Results on the axial charges of hyperons and charmed baryons\nare also presented for a range of pion masses including the physical one.",
        "positive": "3-flavour lattice QCD at finite density and temperature: QCD at finite\n  isospin density revisited: We simulate 3-flavour lattice QCD at finite temperature and isospin chemical\npotential $\\mu_I$. In particular we study the nature of the finite temperature\ntransition for quark masses close to the critical mass at which this transition\nfor zero chemical potentials changes from a first order transition to a\ncrossover. We find that the Binder cumulants, used to determine the position of\nthis transition, have very strong dt dependence. This leads us to an estimate\nof the critical mass which is about 20% below previous estimates. In addition,\nwhen this dt dependence is taken into account, we find that the Binder\ncumulants show very little dependence on mu_I. From this we conclude that we do\nnot as yet see any evidence for the expected critical endpoint. We have argued\npreviously that the position and nature of the finite temperature transition\nfor small mu_I should be the same as that for small quark-number chemical\npotential mu."
    },
    {
        "anchor": "P wave bottomonium spectral functions in the QGP from lattice NRQCD: We present an overview of bottomonium spectral functions in the quark-gluon\nplasma, obtained by the FASTSUM collaboration, using lattice QCD simulations\nwith two light quark flavours on anisotropic lattices. The bottom quark is\ntreated nonrelativistically. While we find that the S wave ground states\nsurvive up to the highest temperature we consider, we have strong indications\nthat P wave states melt immediately above Tc.",
        "positive": "B Meson Decay Constants Using Relativistic Heavy Quarks: We present an update on ongoing work to extract pseudoscalar and vector decay\nconstants for $B^{(*)}$, $B^{(*)}_s$ and $B^{(*)}_c$ mesons and determine\nphenomenologically-interesting ratios such as $f_{B_s}/f_B$ or $f_{B^*}/f_B$.\nOur calculation is based on ${\\rm N_f}=2+1$ dynamical flavour gauge field\nensembles generated by the RBC/UKQCD collaborations using domain-wall fermions\nand the Iwasaki gauge action. Using domain-wall light, strange, and charm\nquarks and relativistic $b$ quarks, we obtain results at multiple lattice\nspacings and valence quark masses."
    },
    {
        "anchor": "Almost gauge-invariant states and the ground state of Yang-Mills theory: We consider the problem of the explicit description of the gauge-invariant\nsubspace of pure lattice gauge theories in the Hamiltonian formulation, where\nthe gauge group is either a compact Lie group or a finite group. The latter\ncase is particularly interesting for quantum simulation. A basis of states\nwhere configurations are grouped according to their holonomies is shown to have\nseveral advantages over other descriptions. Using this basis, we compute some\nproperties of interest for some non- Abelian finite groups on small lattices,\nand in particular we examine the question of whether a certain ansatz\nintroduced long ago is a good approximation for the ground state.",
        "positive": "Thermal QCD for non-perturbative renormalization of composite operators: We present our progresses in the use of the non-perturbative renormalization\nframework based on considering QCD at finite temperature with shifted and\ntwisted (for quarks only) boundary conditions in the compact direction. We\nreport our final results in the application of this method for the\nnon-perturbative renormalization of the flavor-singlet local vector current. We\nthen discuss the more challenging case of the renormalization of the\nenergy-momentum tensor, and show preliminary results on the relevant one-point\nfunctions for the computation of the renormalization constants of its\nnon-singlet components."
    },
    {
        "anchor": "Lattice computation of the Kugo-Ojima correlation function: As of today, color confinement in Quantum Chromodynamics remains a mystery\nfrom the theoretical point of view. So far, no analytical proof of color\nconfinement has been found and the mechanism that confines colored states from\nthe space of physical states is still unknown. Taichiro Kugo and Izumi Ojima\nproposed such confinement mechanism, using as basis the BRST-symmetry and\nderived the requirements for the realization of this mechanism. One such\nrequirement, which happens to be the non-trivial one, is that a special\ncorrelation function, the Kugo-Ojima correlation function $u(p^2)$, approaches\n$-1$ at the origin ($p^2=0)$. This correlation function can be obtained on the\nlattice within the lattice formulation of gauge theories. The present work\nconsists on lattice results for this correlation function on the Landau gauge.\nWe present results obtained from 4 symmetric large volume lattices $(32^{4},\n48^{4}, 64^{4}, 80^{4})$ with $\\beta = 6.0$ on the Landau gauge. A test on the\ntransversality of the Kugo-Ojima correlation function is also performed, along\nwith some statistical considerations of the results. The results present\nfurther evidence that the Kugo-Ojima confinement scenario is not realized on\nthe lattice and that the Kugo-Ojima correlation function, in the Landau gauge,\nis transverse. Our findings align qualitatively with existing literature.",
        "positive": "Chiral Symmetry and hadron properties at finite temperature -A numerical\n  experiment: We study the hadron properties at finite temperature from measurement of the\nscreening masses, using two-flavor full QCD of the hybrid Monte Carlo (HMC)\nalgorithm with the renormalization group improved Iwasaki gauge action and the\nclover improved Wilson quark action on a $16^3 \\times 4$ lattice. We explore\nrather heavy quark mass regions. Disconnected quark diagram is dropped. We\nobserve the tendency that the screening masses in all the channels degenerate,\nwhich is in accord with the effective restoration of U$_{\\rm A}$(1) symmetry,\nand then eventually approach 2$\\pi T$, i.e. the free quark value. In the low\ntemperature region below pseudocritical temperature $T_c$, the screening masses\nin all the channels decrease. We discuss the different features between these\ncalculations and the previous ones."
    },
    {
        "anchor": "A Study of the Complex Action Problem in a Simple Model for Dynamical\n  Compactification in Superstring Theory Using the Factorization Method: The IIB matrix model proposes a mechanism for dynamically generating four\ndimensional space--time in string theory by spontaneous breaking of the ten\ndimensional rotational symmetry $\\textrm{SO}(10)$. Calculations using the\nGaussian expansion method (GEM) lend support to this conjecture. We study a\nsimple $\\textrm{SO}(4)$ invariant matrix model using Monte Carlo simulations\nand we confirm that its rotational symmetry breaks down, showing that lower\ndimensional configurations dominate the path integral. The model has a strong\ncomplex action problem and the calculations were made possible by the use of\nthe factorization method on the density of states $\\rho_n(x)$ of properly\nnormalized eigenvalues $\\tilde\\lambda_n$ of the space--time moment of inertia\ntensor. We study scaling properties of the factorized terms of $\\rho_n(x)$ and\nwe find them in agreement with simple scaling arguments. These can be used in\nthe finite size scaling extrapolation and in the study of the region of\nconfiguration space obscured by the large fluctuations of the phase. The\ncomputed values of $\\tilde\\lambda_n$ are in reasonable agreement with GEM\ncalculations and a numerical method for comparing the free energy of the\ncorresponding ansatze is proposed and tested.",
        "positive": "Non-perturbative determination of anisotropy coefficients in lattice\n  gauge theories: We propose a new non-perturbative method to compute derivatives of gauge\ncoupling constants with respect to anisotropic lattice spacings (anisotropy\ncoefficients), which are required in an evaluation of thermodynamic quantities\nfrom numerical simulations on the lattice. Our method is based on a precise\nmeasurement of the finite temperature deconfining transition curve in the\nlattice coupling parameter space extended to anisotropic lattices by applying\nthe spectral density method. We test the method for the cases of SU(2) and\nSU(3) gauge theories at the deconfining transition point on lattices with the\nlattice size in the time direction $N_t=4$ -- 6. In both cases, there is a\nclear discrepancy between our results and perturbative values. A longstanding\nproblem, when one uses the perturbative anisotropy coefficients, is a\nnon-vanishing pressure gap at the deconfining transition point in the SU(3)\ngauge theory. Using our non-perturbative anisotropy coefficients, we find that\nthis problem is completely resolved: we obtain $\\Delta p/T^4 = 0.001(15)$ and\n$-0.003(17)$ on $N_t=4$ and 6 lattices, respectively."
    },
    {
        "anchor": "Confinement of color: open problems and perspectives: Some basic features of confinement are reviewed, in particular the symmetry\npatterns of the dual dynamics. Open problems and possible directions of\nprogress are discussed.",
        "positive": "Automated label flows for excited states of correlation functions in\n  lattice gauge theory: Extracting excited states from lattice gauge theory correlation functions can\nbe achieved through chi-squared minimization fits or algebraic approaches such\nas the variational method and Prony's method. Performing any kind of error\nanalysis, such as bootstrap resampling, often leads to overlapping confidence\nregions of model parameters, even when the spectrum is not particularly dense.\nIn order to correctly estimate errors, one must beware of mislabeling the\nstates. In this work, we provide an algorithm that we call automated label\nflows which consistently and systematically identifies a deterministic labeling\nof states. In the context of Prony's method, we analyze lattice correlation\nfunctions by using automated label flows, and compare the results to fits\nobtained from chi-square minimization fits to exponentials."
    },
    {
        "anchor": "Finite temperature Lattice QCD with two flavors of improved Wilson\n  fermions: We present results of finite temperature QCD from N_f=2 flavors of\nnon-perturbatively improved Wilson fermions on lattices with N_t=8, 10 and 12.\nThe transition temperature T_c is determined for the first time at lattice\nspacings as low as a = 0.08 fm, albeit at pion masses 1.3 < r_0 m_\\pi. We\nfurthermore compute the screening masses in various color channels at T>T_c.",
        "positive": "Monopole Dominance of Confinement in SU(3) Lattice QCD: To check the dual superconductor picture for the quark-confinement mechanism,\nwe evaluate monopole dominance as well as Abelian dominance of quark\nconfinement for both quark-antiquark and three-quark systems in SU(3) quenched\nlattice QCD in the maximally Abelian (MA) gauge. First, we examine Abelian\ndominance for the static $Q\\bar Q$ system in lattice QCD with various spacing\n$a$ at $\\beta$=5.8-6.4 and various size $L^3$x$L_t$. For large physical-volume\nlattices with $La \\ge$ 2fm, we find perfect Abelian dominance of the string\ntension for the $Q\\bar Q$ systems: $\\sigma_{Abel} \\simeq \\sigma$. Second, we\naccurately measure the static 3Q potential for more than 300 different patterns\nof 3Q systems with 1000-2000 gauge configurations using two large\nphysical-volume lattices: ($\\beta$,$L^3$x$L_t$)=(5.8,$16^3$x32) and\n(6.0,$20^3$x32). For all the distances, the static 3Q potential is found to be\nwell described by the Y-Ansatz: two-body Coulomb term plus three-body Y-type\nlinear term $\\sigma L_{min}$, where $L_{min}$ is the minimum flux-tube length\nconnecting the three quarks. We find perfect Abelian dominance of the string\ntension also for the 3Q systems: $\\sigma^{Abel}_{3Q}\\simeq \\sigma_{3Q} \\simeq\n\\sigma$. Finally, we accurately investigate monopole dominance in SU(3) lattice\nQCD at $\\beta$=5.8 on $16^3$x32 with 2,000 gauge configurations.\nAbelian-projected QCD in the MA gauge has not only the color-electric current\n$j^\\mu$ but also the color-magnetic monopole current $k^\\mu$, which\ntopologically appears. By the Hodge decomposition, the Abelian-projected QCD\nsystem can be divided into the monopole part ($k_\\mu \\ne 0$, $j_\\mu=0$) and the\nphoton part ($j_\\mu \\ne 0$, $k_\\mu=0$). We find monopole dominance of the\nstring tension for $Q\\bar Q$ and 3Q systems: $\\sigma_{Mo}\\simeq 0.92\\sigma$.\nWhile the photon part has almost no confining force, the monopole part almost\nkeeps the confining force."
    },
    {
        "anchor": "Estimate of the charmed 0-- hybrid meson spectrum from quenched lattice\n  QCD: We compute from quenched lattice QCD the ground state masses of the charmed\nhybrid mesons cbar c g, with exotic quantum numbers JPC=1-+, 0+- and 0--. The\n0-- hybrid meson spectrum has never been provided by lattice simulations due to\nthe difficulties to extract high gluonic excitations from noise. We employ\nimproved gauge and fermion actions on the anisotropic lattice, which reduce\ngreatly the lattice artifacts, and lead to very good signals. The data are\nextrapolated to the continuum limit, with finite size effects under well\ncontrol. For 1-+ and 0+- hybrid mesons, the ground state masses are 4.405(38)\nGeV and 4.714(52) GeV. We predict for the first time from lattice QCD, the\nground state mass of 0-- to be 5.883(146) GeV.",
        "positive": "Topological susceptibilty in lattice QCD with exact chiral symmetry --\n  the index of overlap-Dirac operator versus the clover topological charge in\n  Wilson flow: Using an ensemble of 535 gauge configurations (on the $24^4 \\times 48 $\nlattice with $ a \\simeq 0.06 $~fm and $ M_{\\pi} \\simeq 260 $~MeV) which are\ngenerated by hybrid Monte Carlo (HMC) simulation of $N_f=2$ lattice QCD with\nthe optimal domain-wall quark, we compute the index of the overlap-Dirac\noperator, and also measure the clover topological charge in the Wilson flow,\n$Q_{\\text{clover}}(t) $, by integrating the flow equation from $ t = 0 $ to $ t\n= 128 $ with $\\delta t = 0.01 $. We observe that $Q_{\\text{clover}}(t) $ of\neach configuration converges to a value close to an integer, and its nearest\ninteger $Q_c(t) = \\text{round} [Q_{\\text{clover}}(t)] $ becomes invariant for $\nt \\ge t_c $, with the $ \\max\\{t_c \\} \\sim 77 $ for all 535 configurations. For\neach configuration, we compare the asymptotically-invariant $ Q_c $ with the\nindex of overlap-Dirac operator at $t=0$. It turns out that there are 167\nconfigurations with $Q_c \\ne \\text{index}(D_{o}) $, amounting to $31.2\\%$ of\nthe total 535 configurations. However, the histograms of $ Q_c $ and $\n\\text{index}(D_o) $ are almost identical. Consequently, the topological\nsusceptibility using the asymptotically-invariant $ Q_c $ agrees with that\nusing the index of overlap-Dirac operator at $ t=0 $. This implies that the\ntopological susceptibility in lattice QCD with exact chiral symmetry can be\nobtained from the asymptotically-invariant $ Q_c $ in the Wilson flow."
    },
    {
        "anchor": "Extra-dimensional models on the lattice: In this review we summarize the ongoing effort to study extra-dimensional\ngauge theories with lattice simulations. In these models the Higgs field is\nidentified with extra-dimensional components of the gauge field. The Higgs\npotential is generated by quantum corrections and is protected from\ndivergencies by the higher dimensional gauge symmetry. Dimensional reduction to\nfour dimensions can occur through compactification or localization. Gauge-Higgs\nunification models are often studied using perturbation theory. Numerical\nlattice simulations are used to go beyond these perturbative expectations and\nto include non-perturbative effects. We describe the known perturbative\npredictions and their fate in the strongly-coupled regime for various\nextra-dimensional models.",
        "positive": "The pion quasiparticle in the low-temperature phase of QCD: We extend our previous studies [PhysRevD.90.054509, PhysRevD.92.094510] of\nthe pion quasiparticle in the low-temperature phase of two-flavor QCD with\nsupport from chiral effective theory. This includes the analysis performed on a\nfinite temperature ensemble of size $20\\times 64^3$ at $T\\approx 151$MeV and a\nlighter zero-temperature pion mass $m_{\\pi} \\approx 185$ MeV. Furthermore, we\ninvestigate the Gell-Mann--Oakes-Renner relation at finite temperature and the\nDey-Eletsky-Ioffe mixing theorem at finite quark mass."
    },
    {
        "anchor": "Quark Contributions to Nucleon Momentum and Spin from Domain Wall\n  fermion calculations: We report contributions to the nucleon spin and momentum from light quarks\ncalculated using dynamical domain wall fermions with pion masses down to 300\nMeV and fine lattice spacing a=0.084 fm. Albeit without disconnected diagrams,\nwe observe that spin and orbital angular momenta of both u and d quarks are\nopposite, almost canceling in the case of the d quark, which agrees with\nprevious calculations using a mixed quark action. We also present the full\nmomentum dependence of n=2 generalized form factors showing little variation\nwith the pion mass.",
        "positive": "QCDVis: a tool for the visualisation of Quantum Chromodynamics (QCD)\n  Data: Quantum chromodynamics, most commonly referred to as QCD, is a relativistic\nquantum field theory for the strong interaction between subatomic particles\ncalled quarks and gluons. The most systematic way of calculating the strong\ninteractions of QCD is a computational approach known as lattice gauge theory\nor lattice QCD. Space-time is discretised so that field variables are\nformulated on the sites and links of a four dimensional hypercubic lattice.\nThis technique enables the gluon field to be represented using $3 \\times 3$\ncomplex matrices in four space-time dimensions. Importance sampling techniques\ncan then be exploited to calculate physics observables as functions of the\nfields, averaged over a statistically-generated and suitably weighted ensemble\nof field configurations. In this paper we present a framework developed to\nvisually assist scientists in the analysis of multidimensional properties and\nemerging phenomena within QCD ensemble simulations. Core to the framework is\nthe use of topology-driven visualisation techniques which enable the user to\nsegment the data into unique objects, calculate properties of individual\nobjects present on the lattice, and validate features detected using\nstatistical measures. The framework enables holistic analysis to validate\nexisting hypothesis against novel visual cues with the intent of supporting and\nsteering scientists in the analysis and decision making process. Use of the\nframework has lead to new studies into the effect that variation of\nthermodynamic control parameters has on the topological structure of lattice\nfields."
    },
    {
        "anchor": "Nonperturbative renormalization of nonlocal quark bilinears for\n  quasi-PDFs on the lattice using an auxiliary field: Quasi-PDFs provide a path toward an ab initio calculation of parton\ndistribution functions (PDFs) using lattice QCD. One of the problems faced in\ncalculations of quasi-PDFs is the renormalization of a nonlocal operator. By\nintroducing an auxiliary field, we can replace the nonlocal operator with a\npair of local operators in an extended theory. On the lattice, this is closely\nrelated to the static quark theory. In this approach, we show how to understand\nthe pattern of mixing that is allowed by chiral symmetry breaking, and obtain a\nmaster formula for renormalizing the nonlocal operator that depends on three\nparameters. We present an approach for nonperturbatively determining these\nparameters and use perturbation theory to convert to the MS-bar scheme.\nRenormalization parameters are obtained for two lattice spacings using Wilson\ntwisted mass fermions and for different discretizations of the Wilson line in\nthe nonlocal operator. Using these parameters we show the effect of\nrenormalization on nucleon matrix elements with pion mass approximately 370\nMeV, and compare renormalized results for the two lattice spacings. The\nrenormalized matrix elements are consistent among the different Wilson line\ndiscretizations and lattice spacings.",
        "positive": "Applications of Jarzynski's relation in lattice gauge theories: Jarzynski's equality is a well-known result in statistical mechanics,\nrelating free-energy differences between equilibrium ensembles with\nfluctuations in the work performed during non-equilibrium transformations from\none ensemble to the other. In this work, an extension of this relation to\nlattice gauge theory will be presented, along with numerical results for the\n$\\mathbb{Z}_2$ gauge model in three dimensions and for the equation of state in\n$\\mathrm{SU}(2)$ Yang-Mills theory in four dimensions. Then, further\napplications will be discussed, in particular for the Schr\\\"odinger functional\nand for the study of QCD in strong magnetic fields."
    },
    {
        "anchor": "Tetraquark and the flux tube recombination: Here we study the static potential for the two quarks and two antiquarks\nsystem. First this is done using the tetraquark operator, which has been\npreviously used to calculate the static potential. This is found to give good\nresults in the region where the tetraquark is expected to be the ground state,\nhowever failing outside it. To repair this, we resort to a variational method.\nThis let us study the first excited state besides the ground state of the\nsystem in two different particle dispositions, one where the quarks are on the\nsame side of a rectangle and the other where they are at opposite sides.\nResults for the field components and for the lagrangian density are presented.",
        "positive": "Intersection between Microscopic and Macroscopic Abelian Dominance in\n  the Confinement Physics of QCD: We study abelian dominance for confinement in terms of the local gluon\nproperties in the maximally abelian (MA) gauge, where the diagonal component of\nthe gluon is maximized by the gauge transformation. We find microscopic abelian\ndominance on the link-variable for the whole region of $\\beta$ in the lattice\nQCD in the MA gauge. The off-diagonal angle variable, which is not constrained\nby the MA-gauge fixing condition, tends to be random besides the residual gauge\ndegrees of freedom. Within the random-variable approximation for the\noff-diagonal angle variable, we analytically prove that off-diagonal gluon\ncontribution $W^{\\rm off}$ to the Wilson loop obeys the perimeter law in the MA\ngauge. The perimeter-law behavior of $W^{\\rm off}$ is also confirmed using the\nlattice QCD simulation. This indicates macroscopic abelian dominance for the\nstring tension."
    },
    {
        "anchor": "Thermal phase structure of a supersymmetric matrix model: We present initial results from ongoing lattice investigations into the\nthermal phase structure of the Berenstein--Maldacena--Nastase deformation of\nmaximally supersymmetric Yang--Mills quantum mechanics. The phase diagram of\nthe theory depends on both the temperature $T$ and the deformation parameter\n$\\mu$, through the dimensionless ratios $T / \\mu$ and $g \\equiv \\lambda /\n\\mu^3$ with $\\lambda$ the 't Hooft coupling. Considering couplings $g$ that\nspan three orders of magnitude, we reproduce the weak-coupling perturbative\nprediction for the deconfinement $T / \\mu$ and approach recent large-$N$ dual\nsupergravity analyses in the strong-coupling limit. We are carrying out\ncalculations with lattice sizes up to $N_{\\tau} = 24$ and numbers of colors up\nto $N = 16$, to allow initial checks of the large-$N$ continuum limit.",
        "positive": "Fluctuations of Goldstone modes and the chiral transition in QCD: We provide evidence for the influence of thermal fluctuations of Goldstone\nmodes on the chiral condensate at finite temperature. We show that at fixed\ntemperature, T<Tc, in the vicinity of the chiral transition temperature this\nleads to a characteristic dependence of the chiral condensate on the square\nroot of the light quark mass (m_l), which is expected for 3-dimensional models\nwith broken O(N) symmetry. As a consequence the chiral susceptibility shows a\nstrong quark mass dependence for all temperatures below Tc and diverges like\n1/sqrt(m_l) in the chiral limit."
    },
    {
        "anchor": "Character Expansion, Zeros of Partition Function and $\u03b8$-term in\n  U(1) Gauge Theory: Character expansion developed in real space renormalization group (RSRG)\napproach is applied to U(1) lattice gauge theory with $\\th$-term in 2\ndimensions. Topological charge distribution $P(Q)$ is shown to be of Gaussian\nform at any $\\b$(inverse coupling constant). The partition function $Z(\\th)$ at\nlarge volume is shown to be given by the elliptic theta function. It provides\nthe information of the zeros of partition function as an analytic function of\n$\\ze= e^{i \\th}$ ($\\th$ = theta parameter). These partition function zeros lead\nto the phase transition at $\\th=\\pi$. Analytical results will be compared with\nthe MC simulation results. In MC simulation, we adopt (i)``set method\" and\n(ii)``trial function method\".",
        "positive": "Excited mesons on dynamical clover-Wilson lattices: We present results for masses of excited mesons from dynamical clover-Wilson\nlattices provided by the CP-PACS collaboration at pion masses down to 500 MeV.\nOur analysis of the data is based on using a matrix of correlators from various\nsource and sink operators. The spectroscopy results are discussed and compared\nto experimental values."
    },
    {
        "anchor": "Phenomenological applications of non-perturbative heavy quark effective\n  theory: We briefly review the strategy to perform non-perturbative heavy quark\neffective theory computations and we specialize to the case of the b quark mass\nwhich has recently been computed including the 1/m term.",
        "positive": "Dual simulation of a Polyakov loop model at finite baryon density:\n  correlations and screening masses: Computations of screening masses in finite-temperature QCD at finite density\nare plagued by the sign problem and have been performed so far with an\nimaginary chemical potential. Here, we use a dual formulation of a\nPolyakov-loop model which allows the determination of screening masses at real\nbaryon chemical potential. This is a second paper in a series devoted to a\ndetailed study of dual Polyakov-loop models at finite density. While the first\npaper was mainly devoted to establishing the phase diagram of the model, here\nwe compute correlation functions of the Polyakov loops and the second-moment\ncorrelation length at non-zero chemical potential. This enables us to evaluate\nnumerically the screening masses from correlations of the real and imaginary\nparts of the Polyakov loops. We also compute these masses in the mean-field\napproximation and compare with numerical results. In addition, we provide a\nquantitative improvement of the general phase diagram presented in the first\npaper."
    },
    {
        "anchor": "Fluctuations and correlations of net baryon number, electric charge and\n  strangeness in a background magnetic field: We present results on the second-order fluctuations of and correlations among\nnet baryon number, electric charge and strangeness in (2+1)-flavor lattice QCD\nin the presence of a background magnetic field. Simulations are performed using\nthe tree-level improved gauge action and the highly improved staggered quark\n(HISQ) action with a fixed scale approach ($a\\simeq$ 0.117 fm). The light quark\nmass is set to be 1/10 of the physical strange quark mass and the corresponding\npion mass is about 220 MeV at vanishing magnetic field. Simulations are\nperformed on $32^3\\times N_\\tau$ lattices with 9 values of $N_\\tau$ varying\nfrom 96 to 6 corresponding to temperatures ranging from zero up to 281 MeV. The\nmagnetic field strength $eB$ is simulated with 15 different values up to\n$\\sim$2.5 GeV$^2$ at each nonzero temperature. We find that quadratic\nfluctuations and correlations do not show any singular behavior at zero\ntemperature in the current window of $eB$ while they develop peaked structures\nat nonzero temperatures as $eB$ grows. By comparing the electric charge-related\nfluctuations and correlations with hadron resonance gas model calculations and\nideal gas limits we find that the changes in degrees of freedom start at lower\ntemperatures in stronger magnetic fields. Significant effects induced by\nmagnetic fields on the isospin symmetry and ratios of net baryon number and\nbaryon-strangeness correlation to strangeness fluctuation are observed, which\ncould be useful for probing the existence of a magnetic field in heavy-ion\ncollision experiments.",
        "positive": "Towards Quantum Monte Carlo Simulations at non-zero Baryon and Isospin\n  Density in the Strong Coupling Regime: The Hamiltonian formulation of Lattice QCD with staggered fermions in the\nstrong coupling limit has no sign problem at non-zero baryon density and allows\nfor Quantum Monte Carlo simulations. We have extended this formalism to two\nflavors, and after a resummation, there is no sign problem both for non-zero\nbaryon and isospin chemical potential. We report on recent progress on the\nimplementation of the Quantum Monte Carlo simulations."
    },
    {
        "anchor": "Unveiling confinement in pure gauge SU(3): flux tubes, fields, and\n  magnetic currents: A characteristic signature of quark confinement is the concentration of the\nchromoelectric field between a static quark-antiquark pair in a flux tube.\nHowever, the structure of this flux tube, and hence of the confining force, has\nnot been completely understood. Here we perform new lattice measurements of\nfield distributions on smeared Monte Carlo ensembles in SU(3) gauge theory. On\nthe basis of these simulations we demonstrate that the confining force can be\nunderstood using the analogy with the basic principles of electromagnetism as\nelucidated by Maxwell. We derive a chromomagnetic Lorentz force density\ncoupling the chromoelectric field to chromomagnetic currents and integrate this\nforce density over the flux tube interior to obtain a Maxwell-like force that\nsqueezes the flux tube in the transverse direction. We show that the strength\nof this transverse confining force is equal to the value of the string tension\ncalculated numerically from the chromoelectric field on the midplane between\nthe quarks, verifying the consistency of these two complementary pictures of\nconfinement.",
        "positive": "New overlap construction of Weyl fermions: In a recent article Hasenfratz and von Allmen have suggested a fixed point\naction for two flavors of Weyl fermions on the lattice with gauge group SU(2).\nThe block-spin transformation they use maps the chiral and vector symmetries of\nthe underlying vector theory onto two equations of the Ginsparg-Wilson (GW)\ntype. We show that an overlap Dirac operator can be constructed which solves\nboth GW equations simultaneously. We discuss the properties of this overlap\noperator and its projection onto lattice Weyl fermions which seems to be free\nof artefacts, in particular the projection operators are independent of the\ngauge field."
    },
    {
        "anchor": "Testing Improved Actions: We discuss testing improved actions in the context of finite volume gauge\ntheories, where both results for the continuum and the Wilson lattice action\nare known analytically for volumes up to 0.7 fermi across. A new improved\naction is introduced, obtained by adding a 2 x 2 plaquette to the\nL\\\"uscher-Weisz Symanzik action, for which the gauge field propagator greatly\nsimplifies. We call this the square Symanzik action. We present the tree-level\nparameters of this improved action and the value of its Lambda parameter. We\nalso give some Monte Carlo results and discuss some of the issues related to\nviolations of unitarity at the scale of the lattice cutoff due to\nnext-to-nearest coupling in the time direction.",
        "positive": "2+1 flavour Domain Wall Fermion simulations by the RBC and UKQCD\n  collaborations: We review simulations of dynamical domain wall fermions at a fixed inverse\nlattice spacing of 1.73GeV and with pion masses as light as 330MeV and spatial\ndimensions as large as 2.7fm performed by the RBC and UKQCD collaborations.\nThese results include pseudoscalar masses and decay constants and low energy\nconstants of the chiral effective lagrangian. We also review results for the\nneutral kaon mixing amplitude $B_K$, the Kl3 form factor, pseudoscalar meson\nstructure, and vector meson decay constants. In the baryon sector we review\nresults for the spectrum, and nucleon form factors and structure functions.\nHighlights of our programme include preliminary quark masses, and\ndeterminations of $V_{us}$ from both $f_K/f_\\pi$ and from Kl3, and an updated\nresult for $B_K$. We find significant finite volume effects in the nucleon\naxial charge $g_A$ for our $m_\\pi=330$ MeV ensemble on a $(2.7 {\\rm fm})^3$\nlattice, and highlight the importance of large physical volumes for non-trivial\nnucleon physics."
    },
    {
        "anchor": "The Three Dimensional Thirring Model for N_f=4 and N_f=6: We present Monte Carlo simulation results for the three dimensional Thirring\nmodel for numbers of fermion flavors N_f=4 and 6. For N_f=4 we find a second\norder chiral symmetry breaking transition at strong coupling, corresponding to\nan ultra-violet fixed point of the renormalisation group defining a non-trivial\ncontinuum limit. The critical exponents extracted from a fit to a model\nequation of state are distinct from those found for N_f=2. For N_f=6, in\ncontrast, we present evidence for tunnelling between chirally symmetric and\nbroken vacua at strong coupling, implying that the phase transition is first\norder and no continuum limit exists. The implications for the phase diagram of\nthe model in the plane of coupling strength and N_f are briefly discussed.",
        "positive": "Lattice simulations of the QCD chiral transition at real baryon density: State-of-the-art lattice QCD studies of hot and dense strongly interacting\nmatter currently rely on extrapolation from zero or imaginary chemical\npotentials. The ill-posedness of numerical analytic continuation puts severe\nlimitations on the reliability of such methods. Here we use the more direct\nsign reweighting method to perform lattice QCD simulation of the QCD chiral\ntransition at finite real baryon density on phenomenologically relevant\nlattices. This method does not require analytic continuation and avoids the\noverlap problem associated with generic reweighting schemes, so has only\nstatistical but no uncontrolled systematic uncertainties for a fixed lattice\nsetup. This opens up a new window to study hot and dense strongly interacting\nmatter from first principles. We perform simulations up to a baryochemical\npotential-temperature ratio of $\\mu_B/T=2.5$ covering most of the RHIC Beam\nEnergy Scan range in the chemical potential. We also clarify the connection of\nthe approach to the more traditional phase reweighting method."
    },
    {
        "anchor": "Perfect Lattice Actions for the Gross-Neveu Model at large N: Fixed point actions for free and interacting staggered lattice fermions are\nconstructed by iterating renormalization group transformations. At large N the\nfixed point action for the Gross-Neveu model is a perfect action in the sense\nof Hasenfratz and Niedermayer, i.e. cut-off effects are completely eliminated.\nIn particular, the fermionic 1-particle energy spectrum of the lattice theory\nis identical with the one of the continuum even for arbitrarily small\ncorrelation lengths. The cut-off effects of the chiral condensate are\neliminated using a perfect operator. (The paper is stored as a ps-file\ncontaining both the text and 5 figures.)",
        "positive": "The transition to a layered phase in the anisotropic five-dimensional\n  SU(2) Yang-Mills theory: We extend to large lattices the work of a previous investigation of the phase\ndiagram of the anisotropic five-dimensional SU(2) Yang-Mills model using Monte\nCarlo simulations in the regime where the lattice spacing in the fifth\ndimension is larger than in the other four dimensions. We find a first order\nphase transition between the confining and deconfining phase at the anisotropic\nparameter point $\\beta_4=2.60$ which was previously claimed to be the critical\npoint at which the order of the transition changes from first to second. We\nconclude that large lattices are required to establish the first order nature\nof this line of transitions and consequently that the scenario of dimensional\nreduction of the five-dimensional theory to a continuum four-dimensional theory\nvia the existence of the so-called \"layer phase\" is unpromising."
    },
    {
        "anchor": "Anisotropic Lattices and Dynamical Fermions: We report results from full QCD calculations with two flavors of dynamical\nstaggered fermions on anisotropic lattices. The physical anisotropy as\ndetermined from spatial and temporal masses, their corresponding dispersion\nrelations, and spatial and temporal Wilson loops is studied as a function of\nthe bare gauge anisotropy and the bare velocity of light appearing in the Dirac\noperator. The anisotropy dependence of staggered fermion flavor symmetry\nbreaking is also examined. These results will then be applied to the study of\n2-flavor QCD thermodynamics.",
        "positive": "Running Coupling in the SU(2) Lattice Gauge Theory: Scenario according to which the SU(2)-gluodynamics is a theory with a\nnontrivial fixed point is analyzed from the point of view of the modern\nMonte-Carlo (MC) lattice data. It is found that an assumption of the first\norder fixed point g=g_f of the beta function has no contradictions with\nexisting MC lattice data. The beta function parameters are found from the\nrequirement of constant values for critical temperature and string tension in\nMC lattice calculations at 4/g^2 >= 2.30."
    },
    {
        "anchor": "Non-abelian gauged NJL models on the lattice: We use Monte Carlo simulation to probe the phase structure of a SU(2) gauge\ntheory containing $N_f$ Dirac fermion flavors transforming in the fundamental\nrepresentation of the group and interacting through an additional four fermion\nterm. Pairs of physical flavors are implemented using the two tastes present in\na reduced staggered fermion formulation of the theory. The resultant lattice\ntheory is invariant under a set of shift symmetries which correspond to a\ndiscrete subgroup of the continuum chiral-flavor symmetry. The pseudoreal\ncharacter of the representation guarantees that the theory has no sign problem.\nFor the case of $N_f=4$ we observe a crossover in the behavior of the chiral\ncondensate for strong four fermi coupling associated with the generation of a\ndynamical mass for the fermions. At weak gauge coupling this crossover is\nconsistent with the usual continuous phase transition seen in the pure\n(ungauged) NJL model. However, if the gauge coupling is strong enough to cause\nconfinement we observe a much more rapid crossover in the chiral condensate\nconsistent with a first order phase transition",
        "positive": "High-Temperature Properties of the Z(3) Interface in (2+1)-D SU(3) Gauge\n  Theory: We study the high-temperature properties of the Z(3) interface which forms\nbetween the various ordered phases of pure SU(3) gauge theory above a critical\ntemperature. On a (2+1)-D Euclidean lattice, we perform an accurate measurement\nof the interface tension, which shows good agreement with the prediction of\nperturbation theory. We also examine the behaviour of the Debye electric\nscreening mass, and compare this with theoretical predictions."
    },
    {
        "anchor": "Weakly coupled conformal gauge theories on the lattice: Results are reported for the beta-function of weakly coupled conformal gauge\ntheories on the lattice, SU(3) with Nf=14 fundamental and Nf=3 sextet fermions.\nThe models are chosen to be close to the upper end of the conformal window\nwhere perturbation theory is reliable hence a fixed point is expected. The\nstudy serves as a test of how well lattice methods perform in the weakly\ncoupled conformal cases. We also comment on the 5-loop beta-function of two\nmodels close to the lower end of the conformal window, SU(3) with Nf=12\nfundamental and Nf=2 sextet fermions.",
        "positive": "Interquark potential for the charmonium system with almost physical\n  quark masses: We study an interquark QQ^bar potential for the charmonium system, that is\ndetermined from the the equal-time and Coulomb gauge QQ^bar Bethe-Salpeter (BS)\nwavefunction through the effective Schr\\\"odinger equation. This novel approach\nenables us to evaluate a kinetic heavy quark mass m_Q and a proper interquark\npotential at finite quark mass m_Q, which receives all orders of 1/m_Q\ncorrections on the static QQ^bar potential from Wilson loops, simultaneously.\nPrecise information of the interquark potential for both charmonium and\nbottomonium states directly from lattice QCD provides us a chance to improve\nquark potential models, where the spin-independent interquark potential is\nphenomenologically described by the Cornell potential and the spin-dependent\nparts are deduced within the framework of perturbative QCD, from\nfirst-principles calculations. In this study, calculations are carried out in\nboth quenched and dynamical fermion simulations. We first demonstrate that the\ninterquark potential at finite quark mass calculated by the BS amplitude method\nsmoothly approaches the conventional static heavy quark potential from Wilson\nloops in the infinitely heavy quark limit within quenched lattice QCD\nsimulations. Secondly, we determine both spin-independent and -dependent parts\nof the interquark potential for the charmonium system in 2+1 flavor dynamical\nlattice QCD using the PACS-CS gauge configurations at the lightest pion mass,\nM_\\pi=156 MeV."
    },
    {
        "anchor": "On observable particles in theories with a Brout-Englert-Higgs effect: Even at weak coupling the physical, observable spectrum of gauge theories\nwith a Brout-Englert-Higgs effect can deviate from the elementary one of\nperturbation theory. This can be analytically described and treated using the\nFr\\\"ohlich-Morchio-Strocchi mechanism. We confirm this by lattice simulation\nfor an SU(3) gauge theory with a fundamental scalar, a toy model for grand\nunification. We also show that this has experimentally observable consequence,\ne.g., in scattering cross-sections of lepton collisions in this toy model.",
        "positive": "Fate of the $\u03b7'$ in the Quark Gluon Plasma: In this paper we study the $\\eta'$ in $N_f=2+1+1$ lattice QCD simulations at\nfinite temperature. Results are obtained from the analysis of the gluonic\ndefined topological charge density correlator after gradient flow. Our results\nindicate the growth of the $\\eta'$ mass above the pseudocritical temperature,\nassociated with the chiral symmetry restoration. In the vicinity of the\npseudocritical temperature the results are consistent with a small dip in the\n$\\eta'$ mass. The magnitude of the dip is compatible with the reduction of the\n$\\eta'$ mass obtained by experimental analysis and suggests that $\\eta'$ mass\ncomes close to zero temperature non-anomalous contribution."
    },
    {
        "anchor": "Pion-pole contribution to HLbL from twisted mass lattice QCD at the\n  physical point: We report on our computation of the pion transition form factor ${\\cal\nF}_{P\\rightarrow \\gamma^*\\gamma^*}$ from twisted mass lattice QCD in order to\ndetermine the numerically dominant light pseudoscalar pole contribution in the\nhadronic light-by-light scattering contribution to the anomalous magnetic\nmoment of the muon $a_\\mu =(g-2)_\\mu$. The pion transition form factor is\ncomputed directly at the physical point. We present first results for our\nestimate of the pion-pole contribution with kinematic setup for the pion at\nrest.",
        "positive": "A possible new phase in non-perturbatively gauge-fixed Yang-Mills theory: The standard expectation is that gauge fixing cannot alter the physics in the\nphysical sector of a Yang-Mills theory. Here we argue that this may not always\nbe true: in an SU(2) Yang-Mills theory in which the $SU(2)/U(1)$ coset is\nnon-perturbatively gauge fixed, we find that a new phase, with spontaneous\nsymmetry breaking and a Higgs-like mechanism, appears to be a possibility."
    },
    {
        "anchor": "Why the overlap formula does not lead to chiral fermions: We describe a conceptually simple, but important test for the overlap\napproach to the construction of lattice chiral gauge theories. We explain the\nequivalence of the overlap formula with a certain waveguide model for a simple\nset of gauge configurations (the trivial orbit). This equivalence is helpful in\ncarrying out the test, and casts serious doubts on the viability of the overlap\napproach. A recent note by Narayanan and Neuberger which points out a mistake\nin our previous work is irrelevant in this context.",
        "positive": "Gauge anomaly cancellations in SU(2)_L \\times U(1)_Y Electroweak theory\n  on the lattice: We consider the cohomological classification of the 4+2-dimensional\ntopological field, which is proposed by L\\\"uscher, for SU(2)_L \\times U(1)_Y\nelectroweak theory. The dependence on the admissible abelian gauge field of\nU(1)_Y is determined through topological argument, with SU(2)_L gauge field\nfixed as background. We then show the exact cancellation of the local gauge\nanomaly of the mixed type {SU(2)_L}^2 \\times U(1)_Y at finite lattice spacing,\nas well as {U(1)_Y}^3, using the pseudo reality of SU(2)_L and the anomaly\ncancellation conditions in the electroweak theory given in terms of the\nhyper-charges of U(1)_Y."
    },
    {
        "anchor": "Critical Behavior of the chiral condensate at the QCD phase transition: We study the critical behavior of the chiral condensate near the QCD phase\ntransition in the background of two fixed light dynamical (sea) quarks. We\nstudy the condensate for $5.245 \\leq \\beta \\leq 5.3$ and $10^{-10} \\leq m_{val}\n\\leq 10$",
        "positive": "Static quark free energies at finite temperature: We determine the static quark free energies around the transition temperature\nusing 2+1 flavors of staggered fermions. Simulations are carried out on\nN_t=4,6,8 and 10 lattices using physical quark masses. The free energies\nextracted from Polyakov-loop correlators are extrapolated to the continuum\nlimit."
    },
    {
        "anchor": "A new proposal for the fermion doubling problem. II. Improving the\n  operators for finite lattices: In a previous paper I showed how the ideal SLAC derivative and\nsecond-derivative operators for an infinite lattice can be obtained in simple\nclosed form in position space, and implemented very efficiently in a stochastic\nfashion for practical calculations on finite lattices. In this second paper I\nshow how the small (order 1/N) errors introduced by truncating the operators to\na finite lattice may be removed by a small adjustment of coefficients, without\nincurring any additional computational cost. The derivation of these results is\nagain presented in a simple, pedagogical fashion.",
        "positive": "The strong-coupling limit of minimal lattice Landau gauge: We study the gluon and ghost propagators of lattice Landau gauge in the\nstrong coupling limit $\\beta = 0$ in pure SU(2) lattice gauge theory to find\nevidence of the conformal infrared behaviour of these propagators as predicted\nby a variety of functional continuum methods for asymptotically small momenta\n$q^2 \\ll \\Lambda_\\mathrm{QCD}^2$. In the strong-coupling limit, this same\nbehaviour is obtained for the larger values of $a^2q^2$ (in units of the\nlattice spacing $a$), where it is otherwise swamped by the gauge field\ndynamics. Deviations for $a^2 q^2 < 1 $ are well parametrized by a transverse\ngluon mass $\\propto 1/a$. Perhaps unexpectedly, these deviations are thus no\nfinite-volume effect but persist in the infinite-volume limit. They furthermore\ndepend on the definition of gauge fields on the lattice, while the asymptotic\nconformal behaviour does not."
    },
    {
        "anchor": "The Hybrid Monte Carlo Algorithm for Quantum Chromodynamics: The Hybrid Monte Carlo (HMC) algorithm currently is the favorite scheme to\nsimulate quantum chromodynamics including dynamical fermions. In this\ntalk-which is intended for a non-expert audience--I want to bring together\nmethodical and practical aspects of the HMC for full QCD simulations. I will\ncomment on its merits and shortcomings, touch recent improvements and try to\nforecast its efficiency and r\\^ole in future full QCD simulations.",
        "positive": "Instantons and Monopoles in the Nonperturbative QCD: We study the confinement physics in QCD in the maximally abelian (MA) gauge\nusing the SU(2) lattice QCD. To clarify the origin of abelian dominance for the\nlong-range physics, we study the charged-gluon propagator in the lattice QCD,\nand find that the effective mass $m_{ch} \\simeq 0.9 {\\rm GeV}$ of the charged\ngluon is induced by the MA gauge fixing. In the MA gauge, there appears the\nglobal network of the monopole world-line covering the whole system, which\nwould be identified as monopole condensation at a large scale. To prove\nmonopole condensation, we apply the dual gauge formalism to the monopole part,\nand derive the inter-monopole potential from the dual Wilson loop in the MA\ngauge. In the monopole part, which carries the nonperturbative aspects of QCD,\nthe dual gluon mass is evaluated as $m_B \\simeq $0.5GeV, which is the evidence\nof the dual Higgs mechanism by monopole condensation. As for the monopole\nstructure, the large fluctuation of off-diagonal gluons remains around the\nmonopole in the MA gauge, and large cancellation occurs between the diagonal\nand off-diagonal action densities to keep the total QCD action finite. The\ncharged-gluon rich region around the QCD-monopole would provide the effective\nmonopole size as the critical scale of the abelian projected QCD. Instantons\nare expected to appear in the charged-gluon rich region around the monopole\nworld-line in the MA gauge, which leads to the local correlation between\nmonopoles and instantons."
    },
    {
        "anchor": "One Spin Trace Formalism for $ B_K $: It has been known for some time that there are two methods to calculate $ B_K\n$ with staggered fermions: one is the two spin trace formalism and the other is\nthe one spin trace formalism. Until now, the two spin trace formalism has been\nexclusively used for weak matrix element calculations with staggered fermions.\nHere, the one spin trace formalism to calculate $ B_K $ with staggered fermions\nis explained. It is shown that the one spin trace operators require additional\nchiral partner operators in order to keep the continuum chiral behavior. The\nrenormalization of the one spin trace operators is described and compared with\nthe two spin trace formalism.",
        "positive": "Pseudoscalar Meson in Two Flavors QCD with the Optimal Domain-Wall\n  Fermion: We perform hybrid Monte Carlo (HMC) simulatons of two flavors QCD with the\noptimal domain-wall fermion (ODWF) on the 16^3 x 32 lattice (with lattice\nspacing a ~ 0.1 fm), for eight sea-quark masses corresponding to pion masses in\nthe range 228-565 MeV. We calculate the mass and the decay constant of the\npseudoscalar meson, and compare our data with the chiral perturbation theory\n(ChPT). We find that our data is in good agreement with the sea-quark mass\ndependence predicted by the next-to-leading order (NLO) ChPT, and provides a\ndetermination of the low-energy constants \\bar{l}_3 and \\bar{l}_4, the pion\ndecay constant, the chiral condensate, and the average up and down quark mass."
    },
    {
        "anchor": "Lattice study of flavor SU(3) breaking in hyperon beta decay: We present a quenched lattice calculation of all six form factors: vector\n[f_1(q^2)], weak magnetism [f_2(q^2)], induced scalar [f_3(q^2)], axial-vector\n[g_1(q^2)], weak electricity [g_2(q^2)] and induce pseudoscalar [g_3(q^2)] form\nfactors in hyperon semileptonic decay Xi^0 -> Sigma^{+} l nu using domain wall\nfermions. The q^2 dependences of all form factors in the relatively low q^2\nregion are examined in order to evaluate their values at zero momentum\ntransfer. The Xi^0 -> Sigma^+ transition is highly sensitive to flavor SU(3)\nbreaking since this decay corresponds to the direct analogue of neutron beta\ndecay under the exchange of the down quark with the strange quark. The pattern\nof flavor SU(3) breaking effects in the hyperon beta decay is easily exposed in\na comparison to results for neutron beta decay. We measure SU(3)-breaking\ncorrections to f_1(0), f_2(0)/f_1(0) and g_1(0)/f_1(0). A sign of the leading\norder corrections, of which the size is less than a few %, on f_1(0) is likely\nnegative, while f_2(0)/f_1(0) and g_1(0)/f_1(0) receive positive corrections of\norder 16% and 5% respectively. The observed patterns of the deviation from the\nvalues in the exact SU(3) limit does not support some of model estimates. We\nshow that there are nonzero second-class form factors in the Xi^0 -> Sigma^+\ndecay, measuring f_3(0)/f_1(0)=0.14(10) and g_2(0)/g_1(0)=0.68(18), which are\ncomparable to the size of first-order SU(3) breaking. It is also found that the\nSU(3) breaking effect on g_3(0)/g_1(0) agree with the prediction of the\ngeneralized pion-pole dominance.",
        "positive": "SPHERICALLY SYMMETRIC RANDOM WALKS III. POLYMER ADSORPTION AT A\n  HYPERSPHERICAL BOUNDARY: A recently developed model of random walks on a $D$-dimensional\nhyperspherical lattice, where $D$ is {\\sl not} restricted to integer values, is\nused to study polymer growth near a $D$-dimensional attractive hyperspherical\nboundary. The model determines the fraction $P(\\kappa)$ of the polymer adsorbed\non this boundary as a function of the attractive potential $\\kappa$ for all\nvalues of $D$. The adsorption fraction $P(\\kappa)$ exhibits a second-order\nphase transition with a nontrivial scaling coefficient for $0<D<4$, $D\\neq 2$,\nand exhibits a first-order phase transition for $D>4$. At $D=4$ there is a\ntricritical point with logarithmic scaling. This model reproduces earlier\nresults for $D=1$ and $D=2$, where $P(\\kappa)$ scales linearly and\nexponentially, respectively. A crossover transition that depends on the radius\nof the adsorbing boundary is found."
    },
    {
        "anchor": "Cluster expansions and chiral symmetry at large density in 2-color QCD: $SU(N_c)$ lattice gauge theories with $N_f$ flavors of massless staggered\nfermions are considered at high quark chemical potential $\\mu$ and any\ntemperature $T$. In the strong coupling regime (sufficiently small $\\beta$)\nthey have been shown to possess a chiral phase of intact global $U(N_f)\\times\nU(N_f)$ symmetry. The proof is by cluster expansions which converge in the\ninfinite volume limit. Extension to weaker coupling does not appear feasible in\nthe presence of complex fermion determinant. For theories with real\ndeterminant, however, such as 2-color QCD with fundamental fermions, or any\n$N_c$ with even $N_f$ and adjoint fermions, such large $\\mu$ cluster expansions\ncan be used to show chiral behavior of fermionic lattice observables at any\ngauge coupling. Unfortunately, this absence of color\nsuperfluidity/superconductivity at high $\\mu$ appears to be a lattice artifact\ndue to lattice saturation, a serious problem plaguing the standard finite\ndensity formalism on the lattice. Some possible ways of circumventing\nsaturation are discussed.",
        "positive": "Confinement and dual superconductivity of QCD vacuum: The mechanism of dual superconductivity for confinement is reviewed."
    },
    {
        "anchor": "Experiences with the multi-level algorithm: Small expectation values are difficult to measure in Monte Carlo calculations\nas they tend to get swamped by noise. Recently an algorithm has been proposed\nby Luscher and Weisz which allows one to measure expectation values which\npreviously could not be measured reliably in Monte Carlo simulations. We will\ntest our implementation of this algorithm by looking at Polyakov loop\ncorrelators and then explore ways of applying it for measuring large Wilson\nloops.",
        "positive": "Paramagnetic squeezing of QCD matter: We determine the magnetization of Quantum Chromodynamics (QCD) for several\ntemperatures around and above the transition between the hadronic and the\nquark-gluon phases of strongly interacting matter. We obtain a paramagnetic\nresponse that increases in strength with the temperature. We argue that due to\nthis paramagnetism, chunks of quark-gluon plasma produced in non-central heavy\nion collisions should become elongated along the direction of the magnetic\nfield. This anisotropy will then contribute to the elliptic flow v_2 observed\nin such collisions, in addition to the pressure gradient that is usually taken\ninto account. We present a simple estimate for the magnitude of this new effect\nand a rough comparison to the effect due to the initial collision geometry. We\nconclude that the paramagnetic effect might have a significant impact on the\nvalue of v_2."
    },
    {
        "anchor": "On trace anomaly in 2+1 flavor QCD: We report on recent progress by the HotQCD collaboration in studying the\ntrace anomaly at non-zero temperature in 2+1 flavor QCD on lattices with the\ntemporal extent N_tau=4, 6, 8, 10 and 12 using the highly improved staggered\nquark (HISQ) action as well as the asqtad action. We discuss the dependence of\nour lattice results on the scale setting procedure and compare them with hadron\nresonance gas (HRG) calculations as well as to resummed perturbative results.",
        "positive": "Computing the Slope of the Isgur-Wise Function: We propose a method for evaluating the slope (and higher derivatives) of the\nIsgur-Wise function at the zero recoil point using lattice simulations. These\nderivatives are required for the extrapolation of the experimental data for\n$B\\rightarrow D^*l\\bar\\nu$ decays to the zero recoil point, from which the\n$V_{cb}$ element of the CKM-matrix can be determined."
    },
    {
        "anchor": "Non-perturbative determination of improvement coefficients b_m and\n  b_A-b_P and normalisation factor Z_m*Z_P/Z_A with N_f=3 Wilson fermions: We determine non-perturbatively the normalisation constant Z_m*Z_P/Z_A as\nwell as the Symanzik coefficients b_m and b_A-b_P, required in O(a) improved\nquark mass renormalisation with Wilson fermions. The strategy underlying their\ncomputation involves simulations in N_f=3 QCD with O(a) improved massless sea\nand non-degenerate valence quarks in the finite-volume Schroedinger functional\nscheme. Our results, which cover the typical gauge coupling range of\nlarge-volume N_f=2+1 QCD simulations with Wilson fermions at lattice spacings\nbelow 0.1 fm, are of particular use for the non-perturbative calculation of\nO(a) improved renormalised quark masses.",
        "positive": "Screening of hot gluon: We calculate electric and magnetic masses of gluons between T = T_c and 6T_c\nusing lattice QCD (quantum chromodynamics) in the quench approximation. We find\nthat magnetic mass has finite values in this region, and the temperature\ndependence of the electric mass is consistent with that determined using the\nhard-thermal-loop perturbation. The hard-thermal-loop resummation improves\nsignificantly the magnitude of the electric mass comparing to the leading order\nperturbation. Both screening masses have little gauge dependence."
    },
    {
        "anchor": "More on Gribov copies and propagators in Landau-gauge Yang-Mills theory: Fixing a gauge in the non-perturbative domain of Yang-Mills theory is a\nnon-trivial problem due to the presence of Gribov copies. In particular, there\nare different gauges in the non-perturbative regime which all correspond to the\nsame definition of a gauge in the perturbative domain. Gauge-dependent\ncorrelation functions may differ in these gauges. Two such gauges are the\nminimal and absolute Landau gauge, both corresponding to the perturbative\nLandau gauge. These, and their numerical implementation, are described and\npresented in detail. Other choices will also be discussed.\n  This investigation is performed, using numerical lattice gauge theory\ncalculations, by comparing the propagators of gluons and ghosts for the minimal\nLandau gauge and the absolute Landau gauge in SU(2) Yang-Mills theory. It is\nfound that the propagators are different in the far infrared and even at energy\nscales of the order of half a GeV. In particular, also the finite-volume\neffects are modified. This is observed in two and three dimensions. Some\nremarks on the four-dimensional case are provided as well.",
        "positive": "2023 Update of $\\varepsilon_K$ with lattice QCD inputs: We report recent progress on $\\varepsilon_K$ evaluated directly from the\nstandard model (SM) with lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $|V_{ud}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $f_K$, and $m_c$. We\nfind that the standard model with exclusive $|V_{cb}|$ and lattice QCD inputs\ndescribes only 66\\% of the experimental value of $|\\varepsilon_K|$ and does not\nexplain its remaining 34\\%, which corresponds to a strong tension in\n$|\\varepsilon_K|$ at the $4.9\\sigma \\sim 3.9\\sigma$ level between the SM theory\nand experiment. We also find that this tension disappears when we use the\ninclusive value of $|V_{cb}|$ obtained using the heavy quark expansion based on\nthe QCD sum rule approach."
    },
    {
        "anchor": "Gauge-independent transition dividing the confinement phase in the\n  lattice SU(2) gauge-adjoint scalar model: The lattice SU(2) gauge-scalar model with the scalar field in the adjoint\nrepresentation of the gauge group has two completely separated confinement and\nHiggs phases according to the preceding studies based on numerical simulations\nwhich have been performed in the specific gauge fixing based on the\nconventional understanding of the Brout-Englert-Higgs mechanism.\n  In this paper, we re-examine this phase structure in the gauge-independent\nway based on the numerical simulations performed without any gauge fixing. This\nis motivated to confirm the recently proposed gauge-independent\nBrout-Englert-Higgs mechanism for generating the mass of the gauge field\nwithout relying on any spontaneous symmetry breaking. For this purpose we\ninvestigate correlation functions between gauge-invariant operators obtained by\ncombining the original adjoint scalar field and the new field called the\ncolor-direction field which is constructed from the gauge field based on the\ngauge-covariant decomposition of the gauge field due to Cho-Duan-Ge-Shabanov\nand Faddeev-Niemi.\n  Consequently, we reproduce gauge-independently the transition line separating\nconfinement phase and Higgs phase, and show surprisingly the existence of a new\ntransition line that divides completely the confinement phase into two parts.\nFinally, we discuss the physical meaning of the new transition and implications\nto confinement mechanism.",
        "positive": "Multicanonical Hybrid Monte Carlo: Boosting Simulations of Compact QED: We demonstrate that substantial progress can be achieved in the study of the\nphase structure of 4-dimensional compact QED by a joint use of hybrid Monte\nCarlo and multicanonical algorithms, through an efficient parallel\nimplementation. This is borne out by the observation of considerable speedup of\ntunnelling between the metastable states, close to the phase transition, on the\nWilson line. We estimate that the creation of adequate samples (with order 100\nflip-flops) becomes a matter of half a year's runtime at 2 Gflops sustained\nperformance for lattices of size up to 24^4."
    },
    {
        "anchor": "Interface Tension in Quenched QCD: We calculate the tension $\\sigma$ of the interface between the confined and\ndeconfined phases by the histogram method in SU(3) lattice gauge theory for\ntemporal extents of 4 and 6 using the recent high-statistics data by QCDPAX\ncollaboration. The results are $\\sigma/T_c^3 = 0.0292(22)$ and 0.0218(33) for\n$N_t=4$ and 6, respectively. The ratio $\\sigma/T_c^3$ shows a scaling violation\nsimilar to that already observed for the latent heat $\\latent$. However, we\nfind that the physically interesting dimensionless combinations\n$(\\sigma^{3}/\\latent^2 T)^{1/2}$ and $\\sigma T/ \\latent$ scale within the\nstatistical errors.",
        "positive": "Masslessness of ghosts in equivariantly gauge-fixed Yang--Mills theories: We show that the one-loop ghost self-energy in an equivariantly gauge-fixed\nYang--Mills theory vanishes at zero momentum. A ghost mass is forbidden by\nequivariant BRST symmetry, and our calculation confirms this explicitly. The\nfour-ghost self interaction which appears in the equivariantly gauge-fixed\nYang--Mills theory is needed in order to obtain this result."
    },
    {
        "anchor": "Scaling Structures in Four-dimensional Simplicial Gravity: Four-dimensional(4D) spacetime structures are investigated using the concept\nof the geodesic distance in the simplicial quantum gravity. On the analogy of\nthe loop length distribution in 2D case, the scaling relations of the boundary\nvolume distribution in 4D are discussed in various coupling regions i.e.\nstrong-coupling phase, critical point and weak-coupling phase. In each phase\nthe different scaling relations are found.",
        "positive": "QCD with zero, two and four flavors of light quarks - results from QCDSP: We present the results from full QCD simulations with four flavors of light\nstag gered dynamical quarks on {\\it {\\it QCDSP}} supercomputer. Previous\nresults are reproduced and the simulation reported here yields new results\nconsistent with o ur previous runs. The hadron spectrum obtained with Wilson\nvalence fermions reported here will allow us to determine if our earlier\nconclusions are independent of lattice form alism."
    },
    {
        "anchor": "Correlations equalities and some upper bounds for the coupling constant\n  implying area decay of Wilson loop for $Z_3$ lattice gauge theories: Correlation identities are obtained for $Z_3$ lattice gauge theory where the\nbonds of the plaquettes are decorated by generalized three-state Ising\nvariables. Making use of correlation inequalities we obtain the area decay of\nthe Wilson loop observable in a range of the coupling parameter larger than\nthose obtained from mean field theory considerations.",
        "positive": "Monopoles in High Temperature Phase of SU(2) QCD: We investigated a behavior of monopole currents in the high temperature phase\nof abelian projected finite temperature SU(2) QCD in maximally abelian gauge.\nWrapped monopole currents which are closed by periodic boundary play an\nimportant role for the spatial string tension. And the wrapped monopole current\ndensity seems to be non-vanishing in the continuum limit. These results may be\nrelated to Polyakov's analysis of the confinement mechanism using monopole gas\nin 3-dimensional SU(2) gauge theory with Higgs fields."
    },
    {
        "anchor": "Gauge fixing and Gribov copies in pure Yang-Mills on a circle: %In order to understand how gauge fixing can be affected on the %lattice, we\nfirst study a simple model of pure Yang-mills theory on a %cylindrical\nspacetime [$SU(N)$ on $S^1 \\times$ {\\bf R}] where the %gauge fixed subspace is\nexplicitly displayed. On the way, we find that %different gauge fixing\nprocedures lead to different Hamiltonians and %spectra, which however coincide\nunder a shift of states. The lattice %version of the model is compared and\nlattice gauge fixing issues are %discussed. (---TALK GIVEN AT LATTICE\n92---AMSTERDAM, 15 SEPT. 92)",
        "positive": "Hadronic vacuum polarization in the muon $g-2$: The short-distance\n  contribution from lattice QCD: We present results for the short-distance window observable of the hadronic\nvacuum polarization contribution to the muon $g-2$, computed via the\ntime-momentum representation (TMR) in lattice QCD. A key novelty of our\ncalculation is the reduction of discretization effects by a suitable\nsubtraction applied to the TMR kernel function, which cancels the leading\n$x_0^4$-behaviour at short distances. To compensate for the subtraction, one\nmust substitute a term that can be reliably computed in perturbative QCD. We\napply this strategy to our data for the vector current collected on ensembles\ngenerated with $2+1$ flavours of O($a$)-improved Wilson quarks at six values of\nthe lattice spacing and pion masses in the range $130-420\\,$MeV. Our estimate\nat the physical point contains a full error budget and reads $(a_\\mu^{\\rm\nhvp})^{\\rm SD}=68.85(14)_{\\rm stat}\\,(42)_{\\rm syst}\\cdot10^{-10}$, which\ncorresponds to a relative precision of 0.7\\%. We discuss the implications of\nour result for the observed tensions between lattice and data-driven\nevaluations of the hadronic vacuum polarization."
    },
    {
        "anchor": "The static force from generalized Wilson loops using gradient flow: We explore a novel approach to compute the force between a static\nquark-antiquark pair with the gradient flow algorithm on the lattice. The\napproach is based on inserting a chromoelectric field in a Wilson loop. The\nrenormalization issues, associated with the finite size of the chromoelectric\nfield on the lattice, can be solved with the use of gradient flow. We compare\nnumerical results for the flowed static potential to our previous measurement\nof the same observable without a gradient flow.",
        "positive": "Light Quark Masses with Overlap Fermions in Quenched QCD: We present the results of a computation of the sum of the strange and average\nup-down quark masses with overlap fermions in the quenched approximation. Since\nthe overlap regularization preserves chiral symmetry at finite cutoff and\nvolume, no additive quark mass renormalization is required and the results are\nO(a) improved. Our simulations are performed at beta=6.0 and volume V=16^3X32,\nwhich correspond to a lattice cutoff of ~2 GeV and to an extension of ~1.4 fm.\nThe logarithmically divergent renormalization constant has been computed\nnon-perturbatively in the RI/MOM scheme. By using the K-meson mass as\nexperimental input, we obtain (m_s + m_l)^RI(2 GeV) = 120(7)(21) MeV, which\ncorresponds m_s^MS (2 GeV) = 102(6)(18) MeV if continuum perturbation theory\nand ChiPT are used. By using the GMOR relation we also obtain <psi psi>^MS(2\nGeV)/N_f = - 0.0190(11)(33) GeV^3 = - [267(5)(15) MeV]^3."
    },
    {
        "anchor": "Lattice Monte Carlo calculations for unitary fermions in a harmonic trap: We present a new lattice Monte Carlo approach developed for studying large\nnumbers of strongly interacting nonrelativistic fermions, and apply it to a\ndilute gas of unitary fermions confined to a harmonic trap. Our lattice action\nis highly improved, with sources of discretization and finite volume errors\nsystematically removed; we are able to demonstrate the expected volume scaling\nof energy levels of two and three untrapped fermions, and to reproduce the high\nprecision calculations published previously for the ground state energies for N\n= 3 unitary fermions in a box (to within our 0.3% uncertainty), and for N = 3,\n. . ., 6 unitary fermions in a harmonic trap (to within our ~ 1% uncertainty).\nWe use this action to determine the ground state energies of up to 70\nunpolarized fermions trapped in a harmonic potential on a lattice as large as\n64^3 x 72; our approach avoids the use of importance sampling or calculation of\na fermion determinant and employs a novel statistical method for estimating\nobservables, allowing us to generate ensembles as large as 10^8 while requiring\nonly relatively modest computational resources.",
        "positive": "Dark Nuclei II: Nuclear Spectroscopy in Two-Colour QCD: We consider two-colour QCD with two flavours of quarks as a possible theory\nof composite dark matter and use lattice field theory methods to investigate\nnuclear spectroscopy in the spin $J=0$ and $J=1$ multi-baryon sectors. We find\ncompelling evidence that $J=1$ systems with baryon number $B=2,3$ (and their\nmixed meson-baryon counterparts) are bound states - the analogues of nuclei in\nthis theory. In addition, we estimate the $\\sigma$-terms of the $J=0$ and $J=1$\nsingle baryon states which are important for the coupling of the theory to\nscalar currents that may mediate interactions with the visible sector."
    },
    {
        "anchor": "Physical Results from Unphysical Simulations: We calculate various properties of pseudoscalar mesons in partially quenched\nQCD using chiral perturbation theory through next-to-leading order. Our results\ncan be used to extrapolate to QCD from partially quenched simulations, as long\nas the latter use three light dynamical quarks. In other words, one can use\nunphysical simulations to extract physical quantities - in this case the quark\nmasses, meson decay constants, and the Gasser-Leutwyler parameters L_4-L_8. Our\nproposal for determining L_7 makes explicit use of an unphysical (yet\nmeasurable) effect of partially quenched theories, namely the double-pole that\nappears in certain two-point correlation functions. Most of our calculations\nare done for sea quarks having up to three different masses, except for our\nresult for L_7, which is derived for degenerate sea quarks.",
        "positive": "The Calculation of the Perturbative Expansion of Wilson Loops on Lattice: We introduce an approach to expand gauge-invariant Wilson operators on\nlattice. This approach is based on non-abelian Stokes theorem and overcomes\nsome shortage of some former methods. It is also suitable for expanding any\nWilson operators on lattice."
    },
    {
        "anchor": "Simulating 4D Simplicial Gravity including Degenerate Triangulations: We extend simulations of simplicial gravity in four dimensions to include\n{\\it degenerate} triangulations and demonstrate that using this ensemble the\ngeometric finite-size effects are much reduced. We provide strong numerical\nevidence for the existence of an exponential bound on the entropy of the model\nand establish that the phase structure is identical to that of a corresponding\nmodel restricted to an ensemble of combinatorial triangulations.",
        "positive": "Strings in Computer: Complex structures are determined for surfaces with $S^2$ and $T^2$\ntopologies generated by the dynamical triangulation method. For a surface with\n$S^2$ topology the spacial distribution of the conformal mode is obtained,\nwhile for the case of $T^2$ topology the distribution of the moduli parameter\nis calculated. It is also shown that the network of Feynman diagrams of massive\n$\\phi^3$ scalar theory has a unique complex structure. This gives a numerical\njustification of the hadronic string model for explaining the n-particle dual\namplitude."
    },
    {
        "anchor": "Algorithms for Disconnected Diagrams in Lattice QCD: Computing disconnected diagrams in Lattice QCD (operator insertion in a quark\nloop) entails the computationally demanding problem of taking the trace of the\nall to all quark propagator. We first outline the basic algorithm used to\ncompute a quark loop as well as improvements to this method. Then, we motivate\nand introduce an algorithm based on the synergy between hierarchical probing\nand singular value deflation. We present results for the chiral condensate\nusing a 2+1-flavor clover ensemble and compare estimates of the nucleon charges\nwith the basic algorithm.",
        "positive": "Cost of the Generalised Hybrid Monte Carlo Algorithm for Free Field\n  Theory: We study analytically the computational cost of the Generalised Hybrid Monte\nCarlo (GHMC) algorithm for free field theory. We calculate the Metropolis\nacceptance probability for leapfrog and higher-order discretisations of the\nMolecular Dynamics (MD) equations of motion. We show how to calculate\nautocorrelation functions of arbitrary polynomial operators, and use these to\noptimise the GHMC momentum mixing angle, the trajectory length, and the\nintegration stepsize for the special cases of linear and quadratic operators.\nWe show that long trajectories are optimal for GHMC, and that standard HMC is\nmore efficient than algorithms based on Second Order Langevin Monte Carlo\n(L2MC), sometimes known as Kramers Equation. We show that contrary to naive\nexpectations HMC and L2MC have the same volume dependence, but their dynamical\ncritical exponents are z = 1 and z = 3/2 respectively."
    },
    {
        "anchor": "Improving meson two-point functions in lattice QCD: We describe and test a method to compute Euclidean meson two-point functions\nin lattice QCD. The contribution from the low-lying eigenmodes of the Dirac\noperator is averaged over all positions of the quark sources. The contribution\nfrom the higher modes is estimated in the traditional way with one or a few\nsource points per lattice. In some channels, we observe a significant\nimprovement in the two-point functions for small quark masses.",
        "positive": "The vicinity of the phase transition in the lattice Weinberg - Salam\n  Model: We investigated the lattice Weinberg - Salam model without fermions for the\nHiggs mass around $300$ GeV. On the phase diagram there exists the vicinity of\nthe phase transition between the physical Higgs phase and the unphysical\nsymmetric phase, where the fluctuations of the scalar field become strong while\nNambu monopoles are dense. According to our numerical results (obtained on the\nlattices of sizes up to $20^3\\times 24$) the maximal value of the ultraviolet\ncutoff in the model cannot exceed the value around $1.4$ TeV."
    },
    {
        "anchor": "Multi-grid HMC for Ginsparg-Wilson fermions: I describe a method that places the fermion fields and the gauge fields on\ndifferent lattice spacings during the Hybrid Monte Carlo generation of\nGinsparg-Wilson dynamical ensembles. The idea is motivated by Wilson's\nformulation of the renormalisation group. After outlining the underlying\ntheory, I describe a method to perform most of the work of the HMC on a coarse\nlattice, only requiring to convert to and from the fine lattice once for each\nindependent configuration. Because the bulk of the work takes place on the\ncoarse lattice, including the calculation of most observables, this method\nsaves over an order of magnitude in computer time over previous methods.",
        "positive": "Freeze-out parameters from electric charge and baryon number\n  fluctuations: is there consistency?: Recent results for moments of multiplicity distributions of net-protons and\nnet-electric charge from the STAR collaboration are compared to lattice QCD\nresults for higher order fluctuations of baryon number and electric charge by\nthe Wuppertal-Budapest collaboration, with the purpose of extracting the\nfreeze-out temperature and chemical potential. All lattice simulations are\nperformed for a system of 2+1 dynamical quark flavors, at the physical mass for\nlight and strange quarks; all results are continuum extrapolated. We show that\nit is possible to extract an upper value for the freeze-out temperature, as\nwell as precise baryo-chemical potential values corresponding to the four\nhighest collision energies of the experimental beam energy scan. Consistency\nbetween the freeze-out parameters obtained from baryon number and electric\ncharge fluctuations is found. The freeze-out chemical potentials are now in\nagreement with the statistical hadronization model."
    },
    {
        "anchor": "Mass Generation without Phase Coherence at Nonzero Temperature: We present results from numerical simulations of the 2+1d SU(2)xSU(2) Nambu -\nJona-Lasinio model with N_f=4 fermion flavours at zero and nonzero temperature\nT. At zero temperature, critical exponents are extracted from the scaling of\nthe order parameter and fermion mass and are found to be consistent with\nnext-to-leading order predictions of the 1/N_f expansion. At nonzero\ntemperature we observe fermion mass generation despite the lack of chiral\nsymmetry breaking, which is forbidden by the Colemann-Mermin-Wagner theorem for\nall T>0. We study the effects of lattice discretisation and finite volume on\nthe dynamically generated fermion mass. By study of the lattice dispersion\nrelation we also show that in the hot phase there is no significant temperature\ninduced modification to the speed of light. Studies of the equation of state\nare made by measuring the pressure as a function of temperature and comparison\nis made with large-N_f predictions.",
        "positive": "String tension and monopoles in $T \\neq 0$ SU(2) QCD: Monopole and photon contributions to abelian Wilson loops are calculated\nusing Monte-Carlo simulations of finite-temperature $SU(2)$ QCD in the\nmaximally abelian gauge. The string tension is reproduced by monopole\ncontribution alone also in finite temperature SU(2) QCD. The spatial string\ntension scales as $\\sqrt{\\sigma} \\propto g^{2}(T)T$ and is reproduced almost by\nmonopole contribution alone. Each configuration has one long monopole loop, and\nthe long monopole loops alone are responsible for the string tension in the\nconfinement phase. On the other hand, the spatial string tension in the\ndeconfinement phase is reproduced by wrapped monopole loops alone."
    },
    {
        "anchor": "How Do Fermions Behave on a Random Lattice?: Comparing random lattice, naive and Wilson fermions in two dimensional\nabelian background gauge field, we show that the doublers suppressed in the\nfree field case are revived for random lattices in the continuum limit unless\ngauge interactions are implemented in a non--invariant way.",
        "positive": "Complete O(v^2) corrections to the static interquark potential from\n  SU(3) gauge theory: For the first time, we determine the complete spin- and momentum-dependent\norder v^2 corrections to the static interquark potential from simulations of\nQCD in the valence quark approximation at inverse lattice spacings of 2-3 GeV.\nA new flavor dependent correction to the central potential is found. We report\na 1/r^2 contribution to the long range spin-orbit potential V_1'. The other\nspin-dependent potentials turn out to be short ranged and can be well\nunderstood by means of perturbation theory. The momentum-dependent potentials\nqualitatively agree with minimal area law expectations. In view of spectrum\ncalculations, we discuss the matching of the effective nonrelativistic theory\nto QCD as well as renormalization of lattice results. In a first survey of the\nresulting bottomonia and charmonia spectra we reproduce the experimental levels\nwithin average errors of 12.5 MeV and 22 MeV, respectively."
    },
    {
        "anchor": "Landau Levels in Lattice QCD: The spectrum of the two-dimensional continuum Dirac operator in the presence\nof a uniform background magnetic field consists of Landau levels, which are\ndegenerate and separated by gaps. On the lattice the Landau levels are spread\nout by discretization artefacts, but a remnant of their structure is clearly\nvisible (Hofstadter butterfly). If one switches on a non-Abelian interaction,\nthe butterfly structure will be smeared out, but the lowest Landau level (LLL)\nwill still be separated by a gap from the rest of the spectrum. In this talk we\ndiscuss how one can define the LLL in QCD and check how well certain physical\nquantities are approximated by taking into account only the LLL.",
        "positive": "More evidence of localization in the low-lying Dirac spectrum: We have extended our computation of the inverse participation ratio of\nlow-lying (asqtad) Dirac eigenvectors in quenched SU(3). The scaling dimension\nof the confining manifold is clearer and very near 3. We have also computed the\n2-point correlator which further characterizes the localization."
    },
    {
        "anchor": "Flavor Singlet Meson Mass in the Continuum Limit in Two-Flavor Lattice\n  QCD: We present results for the mass of the eta-prime meson in the continuum limit\nfor two-flavor lattice QCD, calculated on the CP-PACS computer, using a\nrenormalization-group improved gauge action, and Sheikholeslami and Wohlert's\nfermion action with tadpole-improved csw. Correlation functions are measured at\nthree values of the coupling constant beta corresponding to the lattice spacing\na approx. 0.22, 0.16, 0.11 fm and for four values of the quark mass parameter\nkappa corresponding to mpi over mrho approx. 0.8, 0.75, 0.7 and 0.6. For each\nbeta, kappa pair, 400-800 gauge configurations are used. The two-loop diagrams\nare evaluated using a noisy source method. We calculate eta-prime propagators\nusing local sources, and find that excited state contributions are much reduced\nby smearing. A full analysis for the smeared propagators gives\nmetaprime=0.960(87)+0.036-0.248 GeV, in the continuum limit, where the second\nerror represents the systematic uncertainty coming from varying the functional\nform for chiral and continuum extrapolations.",
        "positive": "Lattice QCD at Imaginary Chemical Potential in the Chiral Limit: We report on an ongoing study on the interplay between Roberge-Weiss (RW) and\nchiral transitions in simulations of (2+1)-flavor QCD with an imaginary\nchemical potential. We established that the RW endpoint belongs to the 3-$d$,\n$Z_2$ universality class when calculations are done with the Highly Improved\nStaggered Quark (HISQ) action in the RW plane with physical quark masses. We\nalso have explored a range of quark masses corresponding to pion mass values,\n$m_\\pi\\geq40$~MeV and found that the transition is consistent with $Z_2$\nuniversality class. We argue that observables that were usually used to\ndetermine the chiral phase transition temperature, e.g. the chiral condensate\nand chiral susceptibility, are sensitive to the RW transition and are\nenergy-like observables for the $Z_2$ transition, contrary to the magnetic-like\n(order parameter) behavior at vanishing chemical potential. Moreover the\ncalculations performed at $m_\\pi\\sim40$~MeV also put a stringent constraint for\na critical pion mass at zero chemical potential for a possible first-order\nchiral phase transition."
    },
    {
        "anchor": "Nucleon electromagnetic form factors using lattice simulations at the\n  physical point: We present results for the nucleon electromagnetic form factors using an\nensemble of maximally twisted mass clover-improved fermions with pion mass of\nabout 130 MeV. We use multiple sink-source separations and three analysis\nmethods to probe ground-state dominance. We evaluate both the connected and\ndisconnected contributions to the nucleon matrix elements. We find that the\ndisconnected quark loop contributions to the isoscalar matrix elements are\nsmall, giving an upper bound of up to 2$\\%$ of the connected contribution and\nsmaller than its statistical error. We present results for the isovector and\nisoscalar electric and magnetic Sachs form factors and the corresponding proton\nand neutron form factors. By fitting the momentum dependence of the form\nfactors to a dipole form or to the z-expansion we extract the nucleon electric\nand magnetic radii, as well as, the magnetic moment. We compare our results to\nexperiment as well as to other recent lattice QCD calculations.",
        "positive": "Charmonium resonances on the lattice: The nature of resonances and excited states near decay thresholds is encoded\nin scattering amplitudes, which can be extracted from single-particle and\nmultiparticle correlators in finite volumes. Lattice calculations have only\nrecently reached the precision required for a reliable study of such\ncorrelators. The distillation method represents a significant improvement\ninsofar as it simplifies quark contractions and allows one to easily extend the\noperator basis used to construct interpolators. We present preliminary results\non charmonium bound states and resonances on the Nf=2+1 CLS ensembles. The long\nterm goal of our investigation is to understand the properties of the X\nresonances that do not fit into conventional models of quark-antiquark mesons.\nWe tune various parameters of the distillation method and the charm quark mass.\nAs a first result, we present the masses of the ground and excited states in\nthe 0++ and 1-- channels."
    },
    {
        "anchor": "The chiral transition on a 24^3x10 lattice with N_f=2 clover sea quarks\n  studied by overlap valence quarks: Overlap fermions are particularly well suited to study the finite temperature\ndynamics of the chiral symmetry restoration transition of QCD, which might be\njust an analytic crossover. Using gauge field configurations on a 24^3x10\nlattice with N_f=2 flavours of dynamical Wilson-clover quarks generated by the\nDIK collaboration, we compute the lowest 50 eigenmodes of the overlap Dirac\noperator and try to locate the transition by fermionic means. We analyse the\nspectral density, local chirality and localisation properties of the low-lying\nmodes and illustrate the changing topological and (anti-) selfdual structure of\nthe underlying gauge fields across the transition.",
        "positive": "More about QCD on compact spaces: We present some results about spontaneous breaking of global symmetries for\nfour-flavor, three color QCD on compact spaces with two short directions. When\nthe two short directions have equal length and identical boundary conditions,\nthere is a single transition. When the two short directions have boundary\nconditions of opposite parity and are of roughly equal extent, the C-breaking\nand deconfinement transitions separate. When the two short dimensions are of\ndifferent length, the transitions are modified in qualitative agreement with\nexpectations from dimensional reduction. These features resemble the situation\nin pure gauge simulations at small and large number of colors."
    },
    {
        "anchor": "Universality of the Ising Model on Sphere-like Lattices: We study the 2D Ising model on three different types of lattices that are\ntopologically equivalent to spheres. The geometrical shapes are reminiscent of\nthe surface of a pillow, a 3D cube and a sphere, respectively. Systems of\nvolumes ranging up to O($10^5$) sites are simulated and finite size scaling is\nanalyzed. The partition function zeros and the values of various cumulants at\ntheir respective peak positions are determined and they agree with the scaling\nbehavior expected from universality with the Onsager solution on the torus\n($\\nu=1$). For the pseudocritical values of the coupling we find significant\nanomalies indicating a shift exponent $\\neq 1$ for sphere-like lattice\ntopology.",
        "positive": "Flow-based sampling for fermionic lattice field theories: Algorithms based on normalizing flows are emerging as promising machine\nlearning approaches to sampling complicated probability distributions in a way\nthat can be made asymptotically exact. In the context of lattice field theory,\nproof-of-principle studies have demonstrated the effectiveness of this approach\nfor scalar theories, gauge theories, and statistical systems. This work\ndevelops approaches that enable flow-based sampling of theories with dynamical\nfermions, which is necessary for the technique to be applied to lattice field\ntheory studies of the Standard Model of particle physics and many condensed\nmatter systems. As a practical demonstration, these methods are applied to the\nsampling of field configurations for a two-dimensional theory of massless\nstaggered fermions coupled to a scalar field via a Yukawa interaction."
    },
    {
        "anchor": "Field transformation and Monte Carlo simulations: A new method to compute observables at many values of the parameters \\lambda\nfor a model with lattice action {\\cal{S}}(\\phi, \\lambda) is described. After\nfixing a reference set \\lambda^r of parameters, a single simulation is carried\nout by using a ``reference action'' {\\cal{S}} (\\phi^r, \\lambda^r) to generate\nconfigurations of the field \\phi^r. Then a suitable analytic transformation is\nperformed from the configurations of \\phi^r to the ones corresponding to the\naction {\\cal{S}} (\\phi, \\lambda). Such a transformation allows to obtain the\nobservables for values of the parameters \\lambda close to \\lambda^r. I present\nstudies on the reliability of the algorithm in the case of the \\phi^4 model in\n2 dimensions.",
        "positive": "Tricritical Phenomena in a Z(3) Lattice Gauge Theory: The Z(3) gauge model with double plaquette representation of the action on a\ngeneralized Bethe lattice of plaquettes is constructed. It is reduced to the\nspin-1 Blume-Emery-Griffiths (BEG) model. An Ising-type critical line of a\nsecond-order phase transition ending in the tricritical point is found."
    },
    {
        "anchor": "New fermion discretizations and their applications: We review the recent progress in new lattice fermion formulations. We focus\non the following three types which have possibility of improving lattice\nsimulations. (1) Flavored-mass fermions are a generalization of Wilson fermions\nwith species-splitting mass terms. In particular, staggered-Wilson fermions\ninitiated by Adams have possibilities of reducing numerical costs in overlap\nfermions and the influence of taste-breaking in staggered fermions. (2)\nCentral-branch Wilson fermions, in which additive mass renormalization is\nforbidden by extra axial symmetry, could enable us to perform Wilson-fermion\nlattice QCD without fine-tuning. (3) Minimally doubled fermions, which reduce\nthe number of species by species-dependent chemical potential terms, realizes a\nultra-local chiral fermion at the price of hypercubic symmetry. These setups\nreveal unknown aspects of lattice fermions, and we obtain a deeper\nunderstanding of lattice field theory.",
        "positive": "Conformal or Walking? Monte Carlo renormalization group studies of SU(3)\n  gauge models with fundamental fermions: Strongly coupled gauge systems with many fermions are important in many\nphenomenological models. I use the 2-lattice matching Monte Carlo\nrenormalization group method to study the fixed point structure and critical\nindexes of SU(3) gauge models with 8 and 12 flavors of fundamental fermions.\nWith an improved renormalization group block transformation I am able to\nconnect the perturbative and confining regimes of the N_f=8 flavor system, thus\nverifying its QCD-like nature. With N_f=12 flavors the data favor the existence\nof an infrared fixed point and conformal phase, though the results are also\nconsistent with very slow walking. I measure the anomalous mass dimension in\nboth systems at several gauge couplings and find that they are barely different\nfrom the free field value."
    },
    {
        "anchor": "Sanity check for $NN$ bound states in lattice QCD with L\u00fcscher's\n  finite volume formula -- Exposing Symptoms of Fake Plateaux --: A sanity check rules out certain types of obviously false results, but does\nnot catch every possible error. After reviewing such a sanity check for $NN$\nbound states with the L\\\"uscher's finite volume formula[1-3], we give further\nevidences for the operator dependence of plateaux, a symptom of the fake\nplateau problem, against the claim in [4]. We then present our critical\ncomments on [5] by NPLQCD: (i) Operator dependences of plateaux in NPL2013[6,7]\nexist with the $P$-values of 4--5%. (ii) The volume independence of plateaux in\nNPL2013 does not prove their correctness. (iii) Effective range expansion (ERE)\nfits in NPL2013 violate the physical pole condition. (iv) Ref.[5] is partly\nbased on new data and analysis different from the original ones[6,7]. (v) A new\nERE in Refs.[5,8] does not satisfy the L\\\"uscher's finite volume formula.\n  [1] T. Iritani et al., JHEP 10 (2016) 101. [2] S. Aoki et al., PoS\n(LATTICE2016) 109. [3] T. Iritani et al., 1703.0720. [4] T. Yamazaki et al.,\nPoS (LATTICE2017) 108. [5] S.R. Beane et al., 1705.09239. [6] S.R. Beane et\nal., PRD87 (2013) 034506. [7] S.R. Beane et al., PRC88 (2013) 024003. [8] M.L.\nWagman et al., 1706.06550.",
        "positive": "Testing Fermion Universality at a Conformal Fixed Point: Universality of various fermion formulations is well established in QCD-like\ntheories defined around the perturbative $g^2=0$ fixed point. These arguments\ndo not apply for conformal systems that exhibit an infrared fixed point at\nnon-vanishing $g^2$ coupling. We investigate the step scaling function for\nsystems with 10 or 12 fundamental flavors using domain wall fermions and\ncompare it to perturbative predictions. We test universality by contrasting our\nfindings to results published in the literature based on staggered fermions."
    },
    {
        "anchor": "Three-pion effects in $K^0-\\bar{K}^0$ mixing: The rate of mixing between a neutral kaon and an anti-kaon ($K^0-\\bar{K}^0$)\nis given, in part, by a long-range matrix element, defined with two insertions\nof the weak Hamiltonian separated by physical, Minkowski time evolution. For\nphysical quark masses, the kaon mass lies above the two- and three-pion\nthresholds and, as a result, this long-range matrix element receives\ncontributions from intermediate on-shell $2\\pi$ and $3\\pi$ states. These\ncontributions cannot easily be captured in a finite Euclidean spacetime,\nmeaning that such matrix elements are not directly accessible via lattice QCD.\nIn this talk, we present a strategy for combining quantities that can be\nextracted in numerical lattice QCD calculations in order to reproduce the\nphysical, infinite-volume long-range amplitude for $K^0-\\bar{K}^0$. The key\nnovelty relative to published work is that we fully include the effects of\nthree-particle states that were previously neglected. The strategy is built on\nexisting formalism for long-range matrix elements with two-particle\nintermediate states, together with the relativistic-field-theory finite-volume\nformalism for extracting three-hadron weak decays.",
        "positive": "Spectroscopy of doubly-charmed baryons from lattice QCD: We present the ground and excited state spectra of doubly charmed baryons\nfrom lattice QCD with dynamical quark fields. Calculations are performed on\nanisotropic lattices of size 16^3 X 128, with inverse spacing in temporal\ndirection 1/a_t = 5.67(4) GeV and with a pion mass of about 390 MeV. A large\nset of baryonic operators that respect the symmetries of the lattice yet which\nretain a memory of their continuum analogues are used. These operators\ntransform as irreducible representations of SU(3) symmetry for flavor, SU(4)\nsymmetry for Dirac spins of quarks and O(3) for spatial symmetry. The\ndistillation method is utilized to generate baryon correlation functions which\nare analysed using the variational fitting method to extract excited states.\nThe lattice spectra obtained have baryonic states with well-defined total spins\nup to 7/2 and the pattern of low lying states does not support the diquark\npicture for doubly charmed baryons. On the contrary the calculated spectra are\nremarkably similar to the expectations from models with an SU(6)X O(3)\nsymmetry. Various spin dependent energy splittings between the extracted states\nare also evaluated."
    },
    {
        "anchor": "Refining the detection of the zero crossing for the symmetric and\n  asymmetric three-gluon vertices: This article reports on the detailed study of the three-gluon vertex in\nfour-dimensional $SU(3)$ Yang-Mills theory employing lattice simulations with\nlarge physical volumes and high statistics. A meticulous scrutiny of the\nso-called symmetric and asymmetric kinematical configurations is performed and\nit is shown that the associated form-factor changes sign at a given range of\nmomenta. The lattice results are compared to the model independent predictions\nof Schwinger-Dyson equations and a very good agreement among the two is found.",
        "positive": "Lattice results for the decay constant of heavy-light vector mesons: We compute the leptonic decay constants of heavy-light vector mesons in the\nquenched approximation. The reliability of lattice computations for heavy\nquarks is checked by comparing the ratio of vector to pseudoscalar decay\nconstant with the prediction of Heavy Quark Effective Theory in the limit of\ninfinitely heavy quark mass. Good agreement is found. We then calculate the\ndecay constant ratio for B mesons: $f_{B^*}/f_B= 1.01(0.01)(^{+0.04}_{-0.01})$.\nWe also quote quenched $f_{B^*}=177(6)(17)$ MeV."
    },
    {
        "anchor": "Zeta-regularized vacuum expectation values from quantum computing\n  simulations: The zeta-regularization allows to establish a connection between Feynman's\npath integral and Fourier integral operator zeta-functions. This fact can be\nutilized to perform the regularization of the vacuum expectation values in\nquantum field theories. In this proceeding, we will describe the concept of the\nzeta-regularization, give a simple example and demonstrate that quantum\ncomputing can be employed to numerically evaluate zeta-regulated vacuum\nexpectation values on a quantum computer.",
        "positive": "Gauge-variant propagators and the running coupling from lattice QCD: On the occasion of the 70th birthday of Prof. Adriano Di Giacomo we report on\nrecent numerical computations of the Landau gauge gluon and ghost propagators\nas well as of a non-symmetric MOM-scheme ghost-gluon vertex in quenched and\nfull lattice QCD. Special emphasis is paid to the Gribov copy problem and to\nthe unquenching effect. The corresponding running coupling \\alpha_s(q^2) is\nfound and shown to decrease for q^2 \\le 0.3 GeV^2 in the infrared limit. No\nindication for a non-trivial infrared fixed point is seen in agreement with\nfindings from truncated systems of Dyson-Schwinger equations treated on a\nfour-dimensional torus."
    },
    {
        "anchor": "A quenched study of m_b in HQET beyond the leading order: A non perturbative method to compute the mass of the b quark including the\n1/m term in HQET has been presented in a companion talk. Following this\nstrategy, we find in the MS bar scheme m_b^{stat}(m_b) = 4.350(64) GeV for the\nleading term, and m_b^{(1)}(m_b) = -0.049(29) GeV for the next to leading order\ncorrection. This method involves several steps, including the simulation of the\nrelativistic theory in a small volume, and of the effective theory in a big\nvolume. Here we present some numerical details of our calculations.",
        "positive": "The puzzle of apparent linear lattice artifacts in the 2d non-linear\n  sigma-model and Symanzik's solution: Lattice artifacts in the 2d O(n) non-linear sigma-model are expected to be of\nthe form O(a^2), and hence it was (when first observed) disturbing that some\nquantities in the O(3) model with various actions show parametrically stronger\ncutoff dependence, apparently O(a), up to very large correlation lengths. In a\nprevious letter we described the solution to this puzzle. Based on the\nconventional framework of Symanzik's effective action, we showed that there are\nlogarithmic corrections to the O(a^2) artifacts which are especially large,\n(ln(a))^3, for n=3 and that such artifacts are consistent with the data. In\nthis paper we supply the technical details of this computation. Results of\nMonte Carlo simulations using various lattice actions for O(3) and O(4) are\nalso presented."
    },
    {
        "anchor": "Partial deconfinement in gauge theories: We provide the evidence for the existence of partially deconfined phase in\nlarge-$N$ gauge theory. In this phase, the SU($M$) subgroup of SU($N$) gauge\ngroup deconfines, where $\\frac{M}{N}$ changes continuously from zero (confined\nphase) to one (deconfined phase). The partially deconfined phase may exist in\nreal QCD with $N=3$.",
        "positive": "HMC algorithm with multiple time scale integration and mass\n  preconditioning: We describe a new HMC algorithm variant we have recently introduced and\nextend the published results by preliminary results of a simulation with a\npseudo scalar mass value of about 300 MeV. This new run confirms our\nexpectation that simulations with such pseudo scalar mass values become\nfeasible and affordable with our HMC variant. In addition we discuss\nsimulations from hot and cold starts at a pseudo scalar mass value of about 300\nMeV, which we performed in order to test for possible meta-stabilities."
    },
    {
        "anchor": "Visualisations of coherent centre domains in local Polyakov loops: Quantum Chromodynamics exhibits a hadronic confined phase at low to moderate\ntemperatures and, at a critical temperature $T_C$, undergoes a transition to a\ndeconfined phase known as the quark-gluon plasma. The nature of this\ndeconfinement phase transition is probed through visualizations of the Polyakov\nloop, a gauge independent order parameter. We produce visualizations that\nprovide novel insights into the structure and evolution of center clusters.\nUsing the HMC algorithm the percolation during the deconfinement transition is\nobserved. Using 3D rendering of the phase and magnitude of the Polyakov loop,\nthe fractal structure and correlations are examined. The evolution of the\ncenter clusters as the gauge fields thermalize from below the critical\ntemperature to above it are also exposed. We observe deconfinement proceeding\nthrough a competition for the dominance of a particular center phase. We use\nstout-link smearing to remove small-scale noise in order to observe the\nlarge-scale evolution of the center clusters. A correlation between the\nmagnitude of the Polyakov loop and the proximity of its phase to one of the\ncenter phases of SU(3) is evident in the visualizations.",
        "positive": "Polyakov line actions from SU(3) lattice gauge theory with dynamical\n  fermions via relative weights: We extract an effective Polyakov line action from an underlying SU(3) lattice\ngauge theory with dynamical fermions via the relative weights method. The\ncenter-symmetry breaking terms in the effective theory are fit to a form\nsuggested by effective action of heavy-dense quarks, and the effective action\nis solved at finite chemical potential by a mean field approach. We show\nresults for a small sample of lattice couplings, lattice actions, and lattice\nextensions in the time direction. We find in some instances that the long-range\ncouplings in the effective action are very important to the phase structure,\nand that these couplings are responsible for long-lived metastable states in\nthe effective theory. Only one of these states corresponds to the underlying\nlattice gauge theory."
    },
    {
        "anchor": "May vortices produce a mass gap in 2D spin models at weak coupling: We consider the 2D SU(N) principal chiral model and discuss a vortex\ncondensation mechanism which could explain the existence of a non-zero mass gap\nat arbitrarily small values of the coupling constant. The mechanism is an\nanalogue of the vortex condensation mechanism of confinement in 4D non-Abelian\ngauge theories. We formulate a sufficient condition for the mass gap to be\nnon-vanishing in terms of the behaviour of the vortex free energy. The SU(2)\nmodel is studied in detail. In one dimension we calculate the vortex free\nenergy exactly. An effective model for the center variables of the spin\nconfigurations of the 2D SU(2) model is proposed and the Z(2) correlation\nfunction is derived in this model. We define a Z(2) mass gap in both the full\nand effective model and argue that they should coincide whenever the genuine\nmass gap is non-zero. We show via Monte-Carlo simulations of the SU(2) model\nthat the Z(2) mass gap reproduces the full mass gap with perfect accuracy. We\nalso test this mechanism in the positive link model which is an analogue of the\npositive plaquette model in gauge theories and find excellent agreement between\nthe full and the Z(2) mass gap.",
        "positive": "Study of stochastic estimates of quark loops with unbiased subtraction: Stochastic noise estimator method is a powerful tool to calculate the\ndisconnected insertion involving quark loops. We study the variance reduction\ntechnique with unbiased subtraction. We use the complex $Z_2$ noise to\ncalculate the quark loops on a $16^3 \\times 24$ lattice with $\\beta = 6.0$ and\n$\\kappa$ = 0.154. Unbiased subtraction method is performed by using hoping\nparameter expansion. We report on the variance reduction for the point-split\nvector current as a function of the number of subtraction terms and the number\nof noise used."
    },
    {
        "anchor": "Minimally doubled fermions and their renormalization: Minimally doubled fermions have been proposed as a strictly local\ndiscretization of the QCD quark action, which also preserves chiral symmetry at\nfinite cut-off. We study the renormalization and mixing properties of two\nparticular realizations of minimally doubled fermions in lattice perturbation\ntheory at one loop, and we construct conserved axial currents which have a\nsimple form involving only nearest-neighbours sites. We also introduce a\nnotation which allows a unified description of the renormalization properties\nof both actions.",
        "positive": "Finite-Size Scaling at Phase Coexistence: {}From a finite-size scaling (FSS) theory of cumulants of the order parameter\nat phase coexistence points, we reconstruct the scaling of the moments.\nAssuming that the cumulants allow a reconstruction of the free energy density\nno better than as an asymptotic expansion, we find that FSS for moments of low\norder is still complete. We suggest ways of using this theory for the analysis\nof numerical simulations. We test these methods numerically through the scaling\nof cumulants and moments of the magnetization in the low-temperature phase of\nthe two-dimensional Ising model. (LaTeX file; ps figures included as shar file)"
    },
    {
        "anchor": "Center Vortices and the Dirac Spectrum: We study correlations between center vortices and the low-lying eigenmodes of\nthe Dirac operator, in both the overlap and asqtad formulations. In particular\nwe address a puzzle raised some years ago by Gattnar et al. [Nucl. Phys. B 716,\n105 (2005)], who noted that the low-lying Dirac eigenmodes required for chiral\nsymmetry breaking do not appear to be present in center-projected\nconfigurations. We show that the low-lying modes are in fact present in the\nstaggered (asqtad) formulation, but not in the overlap and ``chirally\nimproved'' formulations, and suggest a reason for this difference. We also\nconfirm and extend the results of Kovalenko et al. [Phys. Lett. B 648, 383\n(2007)], showing that there is a correlation between center vortex locations,\nand the scalar density of low-lying Dirac eigenmodes derived from unprojected\nconfigurations. This correlation is strongest at points which are associated,\nin the vortex picture, with non-vanishing topological charge density, such as\nvortex intersection and ``writhing'' points. We present supporting evidence\nthat the lowest Dirac eigenmodes, in both asqtad and overlap formulations, have\ntheir largest concentrations in point-like regions, rather than on submanifolds\nof higher dimensionality.",
        "positive": "Fate of a recent conformal fixed point and $\u03b2$-function in the SU(3)\n  BSM gauge theory with ten massless flavors: SU(3) gauge theory with $N_f$ fermions in the fundamental representation\nserves as a theoretical testing ground for possible infrared conformal\nbehavior, which could play a role in BSM composite Higgs models. We use lattice\nsimulations to study the 10-flavor model, for which it has been claimed there\nis an infrared fixed point in the gauge coupling $\\beta$-function. Our results\nsuggest the opposite conclusion, namely we find no $\\beta$-function fixed point\nin the explored range, with qualitative agreement with the 5-loop\n$\\overline{MS}$ prediction. We comment on the inconsistency between our\nfindings and other studies."
    },
    {
        "anchor": "The epsilon regime of chiral perturbation theory with Wilson-type\n  fermions: In this proceeding contribution we report on the ongoing effort to simulate\nWilson-type fermions in the so called epsilon regime of chiral perturbation\ntheory. We present results for the chiral condensate and the pseudoscalar decay\nconstant obtained with Wilson twisted mass fermions employing two lattice\nspacings, two different physical volumes and several quark masses. With this\nset of simulations we make a first attempt to estimate the systematic\nuncertainties.",
        "positive": "Dual Superconductivity in G2 group: We investigate the dual superconductivity mechanism in the exceptional group\n$G_2$. This is a centerless group (no 't Hooft flux vortices are allowed) and\nwe check for the presence of a magnetic monopole condensate in the confined\nphase by measuring on the lattice a disorder parameter related to the vacuum\nexpectation value of an operator carrying magnetic charge. The behaviour of the\ndisorder parameter is consistent with the dual superconductor picture. A first\nstep of an analysis on the thermodynamical properties of the theory is\nconducted by mean of this operator."
    },
    {
        "anchor": "Numerical tests of the Kugo-Ojima color confinement criterion: The Kugo-Ojima color confinement criterion, which is based on the BRST\nsymmetry of QCD is numerically tested by the lattice Landau gauge simulation.\nWe first discuss the BRST symmetry on the lattice and the Gribov copy problem.\nThe horizon function defined by Zwanziger based on the U-linear definition of\nthe gauge field and that based on log U are compared. The parameter u which is\nexpected to be $-1\\delta^a_b$ in the continuum theory was found to be\n$-0.7\\delta^a_b$ in the strong coupling region. There are about 20% difference\nbetween the two horizon functions, but in the weak coupling region, the\nexpectation value of the horizon function is suggested to be zero or negative.",
        "positive": "Nonperturbative potential for study of quarkonia in QGP: A thermal potential can be defined to facilitate understanding the behavior\nof quarkonia in quark-gluon plasma. A nonperturbative evaluation of this\npotential from lattice QCD is difficult, as it involves real-time corelation\nfunction, and has often involved the use of Bayesian analysis, with its\nassociated systematics. In this work we show that using the properties of the\nstatic quarkonia thermal correlation functions, one can directly extract a\nthermal potential for quarkonia from Euclidean Wilson loop data. This leads to\na controlled extraction, and allows us to judge the suitability of various\nmodel potentials. We also discuss the phenomenology of quarkonia in the gluonic\nplasma."
    },
    {
        "anchor": "Asymptotic behavior of cutoff effects in Yang-Mills theory and in\n  Wilson's lattice QCD: Discretization effects of lattice QCD are described by Symanzik's effective\ntheory when the lattice spacing, $a$, is small. Asymptotic freedom predicts\nthat the leading asymptotic behavior is $\\sim a^n [\\bar\ng^2(a^{-1})]^{\\hat\\gamma_1} \\sim\n  a^n \\left[\\frac{1}{-\\log(a\\Lambda)}\\right]^{\\hat\\gamma_1}$. For spectral\nquantities, $n=d$ is given in terms of the (lowest) canonical dimension, $d+4$,\nof the operators in the local effective Lagrangian and $\\hat\\gamma_1$ is\nproportional to the leading eigenvalue of their one-loop anomalous dimension\nmatrix $\\gamma^{(0)}$. We determine $\\gamma^{(0)}$ for Yang-Mills theory\n($n=2$) and discuss consequences in general and for perturbatively improved\nshort distance observables. With the help of results from the literature, we\nalso discuss the $n=1$ case of Wilson fermions with perturbative O$(a)$\nimprovement and the discretization effects specific to the flavor currents. In\nall cases known so far, the discretization effects are found to disappear\nfaster than the naive $\\sim a^n$ and the log-corrections are a rather weak\nmodification -- in contrast to the two-dimensional O(3) sigma model.",
        "positive": "Nucleon Charges and Sigma Terms from $N_{f}=2+1$ QCD: We report on recent progress of our analysis of the nucleon sigma terms, as\nwell as the singlet scalar, axial and tensor nucleon charges. These are\ndetermined employing the CLS gauge ensembles, which are generated using the\nL\\\"uscher-Weisz gluon action and the non-perturbatively improved\nSheikholeslami-Wohlert fermion action with $N_{f}=2+1$ dynamical fermions. For\nthe ensembles analysed thus far, the pion masses range from 200 MeV up to 410\nMeV, and the lattice spacings take five values between 0.09~fm and 0.04~fm. We\nhave employed a variety of methods to determine the relevant correlation\nfunctions, including the sequential source method for connected contributions\nand the truncated solver method for disconnected contributions."
    },
    {
        "anchor": "$\u039b_c \\to \u039b$ Form Factors in Lattice QCD: Studying the semileptonic decays of charmed particles is prominent in testing\nthe standard model of particle physics. Motivated by recent experimental\nprogress in weak decays of the charm baryon sector, we study the form factors\nof $\\Lambda_c \\to \\Lambda \\ell^+ \\nu$ transition on two flavor lattices. We\ncompute two- and three-point functions, extract the dimensionless projected\ncorrelators, and combine them to form the Weinberg form factors. In the zero\ntransferred momentum limit $f_1$, $f_2$ and $g_1$ form factors are found to be\nin agreement with other models, furthermore $f_3$ and $g_3$ form factors are\ncomparable to model determinations. The $g_2$ form factor, on the other hand,\nis found to be mildly larger. We also evaluate the helicity form factors, which\nis consistent with the previous lattice studies.",
        "positive": "First study of the three-gluon static potential in Lattice QCD: We estimate the potential energy for a system of three static gluons in\nLattice QCD. This is relevant for the different models of three-body glueballs\nhave been proposed in the literature, either for gluons with a constituent\nmass, or for massless ones. A Wilson loop adequate to the static hybrid\nthree-body system is developed. We study different spacial geometries, to\ncompare the starfish model with the triangle model, for the three-gluon\npotential. We also study two different colour structures, symmetric and\nantisymmetric, and compare the respective static potentials. A first simulation\nis performed in a $24^3 \\times 48$ periodic Lattice, with $\\beta=6.2$ and $a\n\\sim 0.072$ fm."
    },
    {
        "anchor": "Spectral-function determination of complex electroweak amplitudes with\n  lattice QCD: We present a novel method to determine on the lattice both the real and\nimaginary parts of complex electroweak amplitudes involving two external\ncurrents and a single hadron or the QCD vacuum in the external states. The\nmethod is based on the spectral representation of the relevant time-dependent\ncorrelation functions and, by extending the range of applicability of other\nrecent proposals built on the same techniques, overcomes the difficulties\nrelated to the analytic continuation from Minkowskian to Euclidean time,\narising when intermediate states with energies smaller than the external states\ncontribute to the amplitude. In its simplest form, the method relies on the\nstandard $i \\varepsilon$ prescription to regularize the Feynman integrals and\nat finite $\\varepsilon$ it requires to verify the condition $1/L \\ll\n\\varepsilon \\ll \\Delta(E)$, where $L$ is the spatial extent of the lattice and,\nfor any given energy $E$, $\\Delta(E)$ represents the typical size of the\ninterval around $E$ in which the hadronic amplitude is significantly varying.\nIn order to illustrate the effectiveness of this approach in a realistic case,\nwe apply the method to evaluate non-perturbatively the hadronic amplitude\ncontributing to the radiative leptonic decay $D_s \\to\\ell\\nu_\\ell\\,\\gamma^*$,\nworking for simplicity with a single lattice ensemble at fixed volume and\nlattice spacing.",
        "positive": "Lattice Gauge Theory Approach to Spontaneous Symmetry Breaking from an\n  Extra Dimension: We present lattice simulation results corresponding to an SU(2) pure gauge\ntheory defined on the orbifold space E_4 x I_1, where E_4 is the\nfour-dimensional Euclidean space and I_1 is an interval, with the gauge\nsymmetry broken to a U(1) subgroup at the two ends of the interval by\nappropriate boundary conditions. We demonstrate that the U(1) gauge boson\nacquires a mass from a Higgs mechanism. The mechanism is driven by two of the\nextra-dimensional components of the five-dimensional gauge field which play\nrespectively the role of the longitudinal component of the gauge boson and a\nmassive real physical scalar, the Higgs particle. Despite the\nnon-renormalizable nature of the theory, we observe only a mild cut-off\ndependence of the physical observables. We also show evidence that there is a\nregion in the parameter space where the system behaves in a way consistent with\ndimensional reduction."
    },
    {
        "anchor": "Tetra-Quark Resonances in Lattice QCD: We study $qq \\bar q \\bar q$-type four-quark (4Q) systems in SU(3)$_c$\nanisotropic quenched lattice QCD, using the $O(a)$-improved Wilson (clover)\nfermion at $\\beta=5.75$ on $12^3 \\times 96$ with renormalized anisotropy\n$a_s/a_t=4$.For comparison, we first investigate the lowest $q\\bar q$ scalar\nmeson from the connected diagram and find its large mass of about 1.32GeV after\nchiral extrapolation, and thus the lowest $q\\bar q$ scalar meson corresponds to\n$f_0(1370)$.We investigate the lowest 4Q state in the spatially periodic\nboundary condition, and find that it is just a two-pion scattering state, as is\nexpected. To examine spatially-localized 4Q resonances, we use the Hybrid\nBoundary Condition (HBC) method, where anti-periodic and periodic boundary\nconditions are imposed on quarks and antiquarks, respectively. By applying HBC\non a finite-volume lattice, the threshold of the two-meson scattering state is\nraised up, while the mass of a compact 4Q resonance is almost unchanged.In HBC,\nthe lowest 4Q state appears slightly below the two-meson threshold. To clarify\nthe nature of the 4Q system, we apply the Maximum Entropy Method (MEM) for the\n4Q correlator and obtain the spectral function of the 4Q system.From the\ncombination analysis of MEM with HBC, we finally conclude that the 4Q system\nappears as a two-pion scattering state and there is no spatially-localized 4Q\nresonance in the quark-mass region of $m_s< m_q <2m_s$.",
        "positive": "DD-$\u03b1$AMG on QPACE 3: We describe our experience porting the Regensburg implementation of the\nDD-$\\alpha$AMG solver from QPACE 2 to QPACE 3. We first review how the code was\nported from the first generation Intel Xeon Phi processor (Knights Corner) to\nits successor (Knights Landing). We then describe the modifications in the\ncommunication library necessitated by the switch from InfiniBand to Omni-Path.\nFinally, we present the performance of the code on a single processor as well\nas the scaling on many nodes, where in both cases the speedup factor is close\nto the theoretical expectations."
    },
    {
        "anchor": "Static meson correlators in 2+1 flavor QCD at non-zero temperature: We study correlation functions of various static meson operators of size r at\nnon-zero temperature in 2+1 flavor QCD, including Coulomb gauge fixed operators\nand Wilson loops with smeared spatial parts. The numerical calculations are\nperformed on 24^3x6 lattices using highly improved staggered quark action. We\ndiscuss possible implications of our findings on the temperature dependence of\nthe static energy of QQbar pair.",
        "positive": "The light bound states of supersymmetric SU(2) Yang-Mills theory: Supersymmetry provides a well-established theoretical framework for\nextensions of the standard model of particle physics and the general\nunderstanding of quantum field theories. We summarise here our investigations\nof N=1 supersymmetric Yang-Mills theory with SU(2) gauge symmetry using the\nnon-perturbative first-principles method of numerical lattice simulations. The\nstrong interactions of gluons and their superpartners, the gluinos, lead to\nconfinement, and a spectrum of bound states including glueballs, mesons, and\ngluino-glueballs emerges at low energies. For unbroken supersymmetry these\nparticles have to be arranged in supermultiplets of equal masses. In lattice\nsimulations supersymmetry can only be recovered in the continuum limit since it\nis explicitly broken by the discretisation. We present the first continuum\nextrapolation of the mass spectrum of supersymmetric Yang-Mills theory. The\nresults are consistent with the formation of supermultiplets and the absence of\nnon-perturbative sources of supersymmetry breaking. Our investigations also\nindicate that numerical lattice simulations can be applied to non-trivial\nsupersymmetric theories."
    },
    {
        "anchor": "New Way to Compute Excited States and Thermodynamics: Monte Carlo\n  Hamiltonian: We present a new way to compute thermodynamical observables on the lattice.\nWe compute excited states and thermodynamical functions in the scalar model via\nthe Monte Carlo Hamiltonian technique. We find agreement with standard\nLagrangian lattice calculations, but observe lesser fluctuations in the results\nfrom the MC Hamiltonian.",
        "positive": "Thermodynamics of SU(3) gauge theory at fixed lattice spacing: We study thermodynamics of SU(3) gauge theory at fixed scales on the lattice,\nwhere we vary temperature by changing the temporal lattice size\nN_t=(Ta_t)^{-1}. In the fixed scale approach, finite temperature simulations\nare performed on common lattice spacings and spatial volumes. Consequently, we\ncan isolate thermal effects in observables from other uncertainties, such as\nlattice artifact, renormalization factor, and spatial volume effect.\nFurthermore, in the EOS calculations, the fixed scale approach is able to\nreduce computational costs for zero temperature subtraction and parameter\nsearch to find lines of constant physics, which are demanding in full QCD\nsimulations. As a test of the approach, we study the thermodynamics of the\nSU(3) gauge theory on isotropic and anisotropic lattices. In addition to the\nequation of state, we calculate the critical temperature and the static quark\nfree energy at a fixed scale."
    },
    {
        "anchor": "Chiral symmetry restoration at finite temperature within the Hamiltonian\n  approach to QCD in Coulomb gauge: The chiral phase transition of the quark sector of QCD is investigated within\nthe Hamiltonian approach in Coulomb gauge. Finite temperature T is introduced\nby compactifying one spatial dimension, which makes all thermodynamical\nquantities accessible from the ground state on the spatial manifold\n$\\small\\mathbb{R}^2 \\times S^1(1/T)$. Neglecting the coupling between quarks\nand transversal gluons, the equations of motion of the quark sector are solved\nnumerically and the chiral quark condensate is evaluated and compared to the\nresults of the usual canonical approach to finite-temperature Hamiltonian QCD\nbased on the density operator of the grand canonical ensemble. For zero bare\nquark masses, we find a second-order chiral phase transition with a critical\ntemperature of about 92 MeV. If the Coulomb string tension is adjusted to\nreproduce the phenomenological value of the quark condensate, the critical\ntemperature increases to 118 MeV.",
        "positive": "Deep Inelastic Scattering in Improved Lattice QCD. II. The second moment\n  of structure functions: In this paper we present the 1-loop perturbative computation of the\nrenormalization constants and mixing coefficients of the lattice quark\noperators of rank three whose hadronic elements enter in the determination of\nthe second moment of Deep Inelastic Scattering (DIS) structure functions.\n  We have employed in our calculations the nearest-neighbor improved\n``clover-leaf'' lattice QCD action. The interest of using this action in Monte\nCarlo simulations lies in the fact that all terms which in the continuum limit\nare effectively of order $a$ ($a$ being the lattice spacing) have been\ndemonstrated to be absent from on-shell hadronic lattice matrix elements. We\nhave limited our computations to the quenched case, in which quark operators do\nnot mix with gluon operators.\n  We have studied the transformation properties under the hypercubic group of\nthe operators up to the rank five (which are related to moments up to the\nfourth of DIS structure functions), and we discuss the choice of the operators\nconsidered in this paper together with the feasibility of lattice computations\nfor operators of higher ranks.\n  To perform the huge amount of calculations required for the evaluation of all\nthe relevant Feynman diagrams, we have extensively used the symbolic\nmanipulation languages Schoonschip and Form."
    },
    {
        "anchor": "Multicanonical study of $D=2$ $O(3)$ nonlinear $\u03c3$-model: We present a new and exploratory approach to determine the\n$\\Delta\\beta(\\beta)$-shift in the $O(3)$ nonlinear $\\sigma$-model. The method\nis based on a scaling hypothesis for a free energy difference, which is assumed\nto be valid in a situation where the mass gap correlation length $\\xi$ is of\nthe order or larger than the linear extent $L$ of the considered square lattice\nsizes. The free energy difference arises from the finite volume constraint\neffective potential of the theory. While the constraint effective potential is\ncalculated in numerical simulations employing a variant of the multicanonical\nensemble on medium sized lattices, it is possible to estimate\n$\\Delta\\beta(\\beta)$ up to a value of $\\beta=2.8$ in the standard\nparameterization of the model.",
        "positive": "Triviality of $\u03c6^4_4$ in the broken phase revisited: We define a finite size renormalization scheme for $\\phi^4$ theory which in\nthe thermodynamic limit reduces to the standard scheme used in the broken\nphase. We use it to re-investigate the question of triviality for the four\ndimensional infinite bare coupling (Ising) limit. The relevant observables all\nrely on two-point functions and are very suitable for a precise estimation with\nthe worm algorithm. This contribution updates an earlier publication by\nanalysing a much larger dataset."
    },
    {
        "anchor": "Charmonium spectroscopy with heavy Kogut-Susskind quarks: Charmonium spectroscopy with Kogut-Susskind valence quarks are carried out\nfor quenched QCD at $\\beta=6.0$ and for two-flavor full QCD at $\\beta=5.7$.\nResults for 1P--1S mass splitting and estimates of\n$\\alpha^{(5)}_{\\overline{MS}}(m_Z)$ are reported. Problems associated with\nflavor breaking effects and finite size effects of $1P$ states are discussed.",
        "positive": "Stabilizing complex Langevin for real-time gauge theories with an\n  anisotropic kernel: The complex Langevin (CL) method is a promising approach to overcome the sign\nproblem that occurs in real-time formulations of quantum field theories. Using\nthe Schwinger-Keldysh formalism, we study SU($N_c$) gauge theories with CL. We\nobserve that current stabilization techniques are insufficient to obtain\ncorrect results. Therefore, we revise the discretization of the CL equations on\ncomplex time contours, find a time reflection symmetric formulation and\nintroduce a novel anisotropic kernel that enables CL simulations on discretized\ncomplex time paths. Applying it to SU(2) Yang-Mills theory in 3+1 dimensions,\nwe obtain unprecedentedly stable results that we validate using additional\nobservables and that can be systematically improved. For the first time, we are\nable to simulate non-Abelian gauge theory on time contours whose real-time\nextent exceeds its inverse temperature. Thus, our approach may pave the way\ntowards an ab-initio real-time framework of QCD in and out of equilibrium with\na potentially large impact on the phenomenology of heavy-ion collisions."
    },
    {
        "anchor": "Spectrum of QCD with one flavor: A window for supersymmetric dynamics: We compute the spectrum of the low-lying mesonic states with vector, scalar\nand pseudoscalar quantum numbers in QCD with one flavour. With three colours\nthe fundamental and the two-index anti-symmetric representations of the gauge\ngroup coincide. The latter is an orientifold theory that maps into the bosonic\nsector of $\\mathcal{N} = 1$ super Yang-Mills theory in the large number of\ncolours limit. We employ Wilson fermions along with tree-level improvement in\nthe gluonic and fermionic parts of the action. In this setup the Dirac operator\ncan develop real negative eigenvalues. We therefore perform a detailed study in\norder to identify configurations where the fermion determinant is negative and\neventually reweight them. We finally compare results with effective field\ntheory predictions valid in the large $N_C$ limit and find reasonably\nconsistent values despite $N_C$ being only three. Additionally,the spin-one\nsector provides a novel window for supersymmetric dynamics.",
        "positive": "Detailed analysis of excited state systematics in a lattice QCD\n  calculation of $g_A$: Excited state contamination remains one of the most challenging sources of\nsystematic uncertainty to control in lattice QCD calculations of nucleon matrix\nelements and form factors: early time separations are contaminated by excited\nstates and late times suffer from an exponentially bad signal-to-noise problem.\nHigh-statistics calculations at large time separations $\\gtrsim1$ fm are\ncommonly used to combat these issues. In this work, focusing on $g_A$, we\nexplore the alternative strategy of utilizing a large number of relatively\nlow-statistics calculations at short to medium time separations (0.2--1 fm),\ncombined with a multi-state analysis. On an ensemble with a pion mass of\napproximately 310 MeV and a lattice spacing of approximately 0.09 fm, we find\nthis provides a more robust and economical method of quantifying and\ncontrolling the excited state systematic uncertainty. A quantitative separation\nof various types of excited states enables the identification of the transition\nmatrix elements as the dominant contamination. The excited state contamination\nof the Feynman-Hellmann correlation function is found to reduce to the 1% level\nat approximately 1 fm while for the more standard three-point functions, this\ndoes not occur until after 2 fm. Critical to our findings is the use of a\nglobal minimization, rather than fixing the spectrum from the two-point\nfunctions and using them as input to the three-point analysis. We find that the\nground state parameters determined in such a global analysis are stable against\nvariations in the excited state model, the number of excited states, and the\ntruncation of early-time or late-time numerical data."
    },
    {
        "anchor": "Towards precise relativistic b quarks on the lattice: We discuss the status of our ongoing efforts to improve on our calculation of\nthe $D_s$ decay constant. We show preliminary results on the ratio of the charm\nto the strange quark mass. We also present preliminary results for\nspectroscopy, decay constants and bottom quark mass obtained by performing\ncalculations with highly improved staggered quarks at masses above the c mass\nand close to the b mass.",
        "positive": "Anatomy of the sign-problem in heavy-dense QCD: QCD at finite densities of heavy quarks is investigated using the\ndensity-of-states method. The phase factor expectation value of the quark\ndeterminant is calculated to unprecedented precision as a function of the\nchemical potential. Results are validated using those from a reweighting\napproach where the latter can produce a significant signal-to-noise ratio. We\nconfirm the particle-hole symmetry at low temperatures, find a strong sign\nproblem at intermediate values of the chemical potential, and an inverse Silver\nBlaze feature for chemical potentials close to the onset value: here, the phase\nquenched theory underestimates the density of the full theory."
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory. Convergence and features of\n  the stochastic process. Computations at fixed (Landau) Gauge: Concerning Numerical Stochastic Perturbation Theory, we discuss the\nconvergence of the stochastic process (idea of the proof, features of the limit\ndistribution, rate of convergence to equilibrium). Then we also discuss the\nexpected fluctuations in the observables and give some idea to reduce them. In\nthe end we show that also computation of quantities at fixed (Landau) Gauge is\nnow possible.",
        "positive": "Bound isoscalar axial-vector $bc\\bar u\\bar d$ tetraquark $T_{bc}$ in QCD: We report a lattice QCD study of the heavy-light meson-meson interactions\nwith an explicitly exotic flavor content $bc\\bar u\\bar d$, isospin $I\\!=\\!0$,\nand axialvector $J^P=1^+$ quantum numbers in search of possible tetraquark\nbound states. We employ four lattice QCD ensembles with dynamical $u/d$, $s$,\nand $c$ quark fields, generated by the MILC Collaboration with a highly\nimproved staggered quark fermion action. The valence quarks, with quark masses\nranging from light to the charm sector, are implemented using an overlap\naction. For bottom quark we use a nonrelativistic QCD Hamiltonian, including\nimprovement coefficients up to $\\mathcal{O}(\\alpha_sv^4)$. The calculation is\nperformed at four values of lattice spacing, ranging in between of about 0.058\nto 0.12 fm, and at five different values of valence light-quark mass $m_{u/d}$,\ncorresponding to pseudoscalar meson mass $M_{ps}$ of about 0.5, 0.6, 0.7, 1.0,\nand 3.0 GeV. The finite-volume energy spectra are determined through a\nvariational procedure applied to correlation matrices built out of two-meson\ninterpolating operators as well as local diquark-antidiquark operators. We\nperform global fits to the lattice extracted $DB^*$ scattering amplitude,\nsupplemented by terms describing discretization effects and $m_{u/d}$\ndependence, then extrapolate the lattice spacing to zero and $m_{u/d}$ to its\nphysical value. The $DB^*$ scattering length at the physical $M_{ps}$ is found\nto be $a_0^{phys} = +0.57(^{+4}_{-5})(17)$ fm, which clearly points to an\nattractive interaction between the $D$ and $B^*$ mesons that is strong enough\nto host a real bound state $T_{bc}$, $43(^{+7}_{-6})(^{+24}_{-14})$ MeV below\nthe $DB^*$ threshold. We also find that the strength of the binding decreases\nwith increasing $m_{u/d}$ and the system becomes unbound at a critical light\nquark mass $m^{*}_{u/d}$ corresponding to $M^{*}_{ps} = 2.73(21)(14)$ GeV."
    },
    {
        "anchor": "The lattice extraction of the TMD soft function using the auxiliary\n  field representation of the Wilson line: The TMD soft function can be obtained by formulating the Wilson line in terms\nof auxiliary 1-dimensional fermion fields on the lattice. In this formulation,\nthe directional vector of the auxiliary field in Euclidean space has the form\n$\\tilde n = (in^0, \\vec 0_\\perp, n^3)$, where the time component is purely\nimaginary. The components of these complex directional vectors in the Euclidean\nspace can be mapped directly to the rapidities of the Minkowski space soft\nfunction. We present the results of the one-loop calculation of the Euclidean\nspace analog to the soft function using these complex directional vectors. As a\nresult, we show that the calculation is valid only when the directional vectors\nobey the relation: $|r| = |n^3/n^0| > 1$, and that this result corresponds to a\ncomputation in Minkowski space with space-like directed Wilson lines. Finally,\nwe show that a lattice calculable object can be constructed that has the\ndesired properties of the soft function.",
        "positive": "One dimensional supersymmetric Yang-Mills theory with 16 supercharges: We report on numerical simulations of one dimensional maximally\nsupersymmetric SU(N) Yang-Mills theory, by using the lattice action with two\nexact supercharges. Based on the gauge/gravity duality, the gauge theory\ncorresponds to N D0-branes system in type IIA superstring theory at finite\ntemperature. We aim to verify the gauge/gravity duality numerically by\ncomparing our results of the gauge side with analytic solutions of the gravity\nside. First of all, by examining the supersymmetric Ward-Takahashi relation, we\nshow that supersymmetry breaking effects from the cut-off vanish in the\ncontinuum limit and our lattice theory has the desired continuum limit. Then,\nwe find that, at low temperature, the black hole internal energy obtained from\nour data is close to the analytic solution of the gravity side. It suggests the\nvalidity of the duality."
    },
    {
        "anchor": "Study of intermediate states in the inclusive semileptonic $B\n  \\rightarrow X_c l \u03bd$ decay structure function: We analyze the inclusive semileptonic $B \\to X_c \\ell\\nu$ structure functions\nin 2+1-flavor lattice QCD. The M\\\"obius domain-wall fermion action is used for\nlight, strange, charm and bottom quarks. The structure function receives\ncontributions from various exclusive modes, including the dominant S-wave\nstates $D^{(*)}_s$ as well as the P-wave states $D_s^{**}$. We can identify\nthem in the lattice data, from which we put some constraints on the $B_s \\to\nD_s^{**}\\ell\\nu$ form factors.",
        "positive": "Monte Carlo Hamiltonian of lattice gauge theory: We discuss how the concept of the Monte Carlo Hamiltonian can be applied to\nlattice gauge theories."
    },
    {
        "anchor": "Properties and uses of the Wilson flow in lattice QCD: Theoretical and numerical studies of the Wilson flow in lattice QCD suggest\nthat the gauge field obtained at flow time t>0 is a smooth renormalized field.\nThe expectation values of local gauge-invariant expressions in this field are\nthus well-defined physical quantities that probe the theory at length scales on\nthe order of sqrt(t). Moreover, by transforming the QCD functional integral to\nan integral over the gauge field at a specified flow time, the emergence of the\ntopological (instanton) sectors in the continuum limit becomes transparent and\nis seen to be caused by a dynamical effect that rapidly separates the sectors\nwhen the lattice spacing is reduced from 0.1 fm to smaller values.",
        "positive": "A Lattice Study of Spectator Effects in Inclusive Decays of B-Mesons: We compute the matrix elements of the operators which contribute to spectator\neffects in inclusive decays of $B$-mesons. The results agree well with\nestimates based on the vacuum saturation (factorization) hypothesis. For the\nratio of lifetimes of charged and neutral mesons we find\n$\\tau(B^-)/\\tau(B_d)=1.03\\pm 0.02\\pm 0.03$, where the first error represents\nthe uncertainty in our evaluation of the matrix elements, and the second is an\nestimate of the uncertainty due to the fact that the Wilson coefficient\nfunctions have only been evaluated at tree-level in perturbation theory. This\nresult is in agreement with the experimental measurement. We also discuss the\nimplications of our results for the semileptonic branching ratio and the charm\nyield."
    },
    {
        "anchor": "Phase diagram of the lattice G(2) Higgs Model: We study the phases and phase transition lines of the finite temperature G(2)\nHiggs model. Our work is based on an efficient local hybrid Monte-Carlo\nalgorithm which allows for accurate measurements of expectation values,\nhistograms and susceptibilities. On smaller lattices we calculate the phase\ndiagram in terms of the inverse gauge coupling $\\beta$ and the hopping\nparameter $\\kappa$. For $\\kappa\\to 0$ the model reduces to G(2) gluodynamics\nand for $\\kappa\\to\\infty$ to SU(3) gluodynamics. In both limits the system\nshows a first order confinement-deconfinement transition. We show that the\nfirst order transitions at asymptotic values of the hopping parameter are\nalmost joined by a line of first order transitions. A careful analysis reveals\nthat there exists a small gap in the line where the first order transitions\nturn into continuous transitions or a cross-over region. For $\\beta\\to\\infty$\nthe gauge degrees of freedom are frozen and one finds a nonlinear O(7) sigma\nmodel which exhibits a second order transition from a massive O(7)-symmetric to\na massless O(6)-symmetric phase. The corresponding second order line for large\n$\\beta$ remains second order for intermediate $\\beta$ until it comes close to\nthe gap between the two first order lines. Besides this second order line and\nthe first order confinement-deconfinement transitions we find a line of\nmonopole-driven bulk transitions which do not interfer with the\nconfinement-deconfinment transitions.",
        "positive": "BKT phase transitions in two-dimensional non-Abelian spin models: It is argued that two-dimensional U(N) spin models for any N undergo a\nBKT-like phase transition, similarly to the famous XY model. This conclusion\nfollows from the Berezinskii-like calculation of the two-point correlation\nfunction in U(N) models, approximate renormalization group analysis and\nnumerical investigations of the U(2) model. It is shown, via Monte Carlo\nsimulations, that the universality class of the U(2) model coincides with that\nof the XY model. Moreover, preliminary numerical results point out that\ntwo-dimensional SU(N) spin models with the fundamental and adjoint terms and\nN>4 exhibit two phase transitions of BKT type, similarly to Z(N) vector models."
    },
    {
        "anchor": "The Physical Hilbert Space of SU(2) Lattice Gauge Theory: We solve the Gauss law of SU(2) lattice gauge theory using the harmonic\noscillator prepotential formulation. We construct a generating function of a\nmanifestly gauge invariant and orthonormal basis in the physical Hilbert space\nof (d+1) dimensional SU(2) lattice gauge theory. The resulting orthonormal\nphysical states are given in closed form. The generalization to SU(N) gauge\ngroup is discussed.",
        "positive": "Nonperturbatively-renormalized glue momentum fraction at physical pion\n  mass from Lattice QCD: We present the first nonperturbatively-renormalized determination of the glue\nmomentum fraction $\\langle x \\rangle_g$ in the nucleon, based on lattice-QCD\nsimulations at physical pion mass using the cluster-decomposition error\nreduction (CDER) technique. We provide the first practical strategy to\nrenormalize the glue energy-momentum tensor (EMT) nonperturbatively in the\nRI/MOM scheme, and convert the results to the $\\overline{\\textrm{MS}}$ scheme\nwith 1-loop matching. The simulation results show that the CDER technique can\nreduce the statistical uncertainty of its renormalization constant by a factor\nof ${\\cal O}$(300) in calculations using typical state-of-the-art lattice\nvolume, and the nonperturbatively-renormalized $\\langle x \\rangle_g$ is shown\nto be independent of the lattice definitions of the glue EMT up to\ndiscretization errors. We determine the renormalized $\\langle x\n\\rangle_g^{\\overline{\\textrm{MS}}}(2\\textrm{ GeV})$ to be 0.47(4)(11) at\nphysical pion mass, which is consistent with the experimentally-determined\nvalue."
    },
    {
        "anchor": "Breaking of the gauge symmetry in lattice gauge theories: We study perturbations that break gauge symmetries in lattice gauge theories.\nAs a paradigmatic model, we consider the three-dimensional Abelian-Higgs (AH)\nmodel with an N-component scalar field and a noncompact gauge field, which is\ninvariant under U(1) gauge and SU(N) transformations. We consider\ngauge-symmetry breaking perturbations that are quadratic in the gauge field,\nsuch as a photon mass term, and determine their effect on the critical behavior\nof the gauge-invariant model, focusing mainly on the continuous transitions\nassociated with the charged fixed point of the AH field theory. We discuss\ntheir relevance and compute the (gauge-dependent) exponents that parametrize\nthe departure from the critical behavior (continuum limit) of the\ngauge-invariant model. We also address the critical behavior of lattice AH\nmodels with broken gauge symmetry, showing an effective enlargement of the\nglobal symmetry, from U(N) to O(2N), which reflects a peculiar cyclic\nrenormalization-group flow in the space of the lattice AH parameters and of the\nphoton mass.",
        "positive": "Pure-gauge SU(2) on large lattices: We have calculated the $q\\bar q$ potential over a wide range of lattice\nseparations on a $48^3\\cdot56$ lattice at $\\beta = 2.85$. We are able to\ninvestigate both long-range and (by correcting for the effects of lack of\nrotational invariance) short-range potentials. From the former we estimate the\nstring tension and from the latter we are able to investigate asymptotic\nscaling. Fitting to this enables us to give an estimate for the\n$\\Lambda$-parameter of pure-gauge SU(2)."
    },
    {
        "anchor": "Strong coupling analysis of diquark condensation: The phenomenon of diquark condensation at non-zero baryon density and zero\ntemperature is analyzed in the strong coupling limit of lattice QCD. The\nresults indicate that there is attraction in the quark-quark channel also at\nstrong coupling, and that the attraction is more effective at high baryon\ndensity, but for infinite coupling it is not enough to produce diquark\ncondensation. It is argued that the absence of diquark condensation is not a\npeculiarity of the strong coupling limit, but persists at sufficiently large\nfinite couplings.",
        "positive": "Continuous renormalization group $\u03b2$ function from lattice\n  simulations: We present a real-space renormalization group transformation with continuous\nscale change to calculate the continuous renormalization group $\\beta$ function\nin non-perturbative lattice simulations. Our method is motivated by the\nconnection between Wilsonian renormalization group and the gradient flow\ntransformation. It does not rely on the perturbative definition of the\nrenormalized coupling and is also valid at non-perturbative fixed points.\nAlthough our method requires an additional extrapolation compared to\ntraditional step scaling calculations, it has several advantages which\ncompensates for this extra step even when applied in the vicinity of the\nperturbative fixed point. We illustrate our approach by calculating the $\\beta$\nfunction of 2-flavor QCD and show that lattice predictions from individual\nlattice ensembles, even without the required continuum and finite volume\nextrapolations, can be very close to the result of the full analysis. Thus our\nmethod provides a non-perturbative framework and intuitive understanding into\nthe structure of strongly coupled systems, in addition to being complementary\nto existing lattice determinations."
    },
    {
        "anchor": "SU(2) chiral fits to light pseudoscalar masses and decay constants: We present the results of fits to recent asqtad data in the light\npseudoscalar sector using SU(2) partially-quenched staggered chiral\nperturbation theory. Superfine (a~0.06 fm) and ultrafine (a~0.045 fm) ensembles\nare used, where light sea quark masses and taste splittings are small compared\nto the strange quark mass. Our fits include continuum NNLO chiral logarithms\nand analytic terms. We give preliminary results for the pion decay constant,\nSU(2) low-energy constants and the chiral condensate in the two-flavor chiral\nlimit.",
        "positive": "Improved actions and lattice coarsening effects in MCRG studies in SU(2)\n  LGT: We study decimation procedures and effective (improved) actions in the\nframework of Monte Carlo Renormalization Group (MCRG). Particular attention is\npaid to matching the form of the effective action to the decimation procedure\nparameters. Using the static quark-antiquark potential in SU(2) LGT we probe\ndifferent distance scales and find that an effective action containing multiple\ngroup representations is capable of reproducing long distance physics well. In\nparticular, appropriate matching results in the practical elimination of the\ncoarsening/fining effect of the lattice spacing under decimation. The short\ndistance regime of the effective theory is also studied. We next carry out\nstudies of effective actions involving both multiple representations and loops\nbeyond the single plaquette towards determining an improved action good over a\nwide length scale regime."
    },
    {
        "anchor": "Quark number density at imaginary chemical potential and its\n  extrapolation to large real chemical potential by the effective model: We evaluate quark number densities at imaginary chemical potential by lattice\nQCD with clover-improved two-flavor Wilson fermion. The quark number densities\nare extrapolated to the small real chemical potential region by assuming some\nfunction forms. The extrapolated quark number densities are consistent with\nthose calculated at real chemical potential with the Taylor expansion method\nfor the reweighting factors. In order to study the large real chemical\npotential region, we use the two-phase model consisting of the quantum\nhadrodynamics model for the hadron phase and the entanglement-PNJL model for\nthe quark phase. The quantum hadrodynamics model is constructed to reproduce\nnuclear saturation properties, while the entanglement-PNJL model reproduces\nwell lattice QCD data for the order parameters such as the Polyakov loop, the\nthermodynamic quantities and the screening masses. Then, we calculate the\nmass-radius relation of neutron stars and explore the hadron-quark phase\ntransition with the two-phase model.",
        "positive": "Lattice QCD Method To Study Hadron Mass Is Not Correct: Since the numerical path integration in the lattice QCD involves quark and\ngluon fields (not hadron fields) the lattice QCD cannot calculate any hadronic\nobservable. Because of this reason the hadronic properties are extracted in the\nlattice QCD method by inserting complete set of hadron states $\\sum_n |n><n|=1$\nin between the partonic operators by assuming $H_{\\rm QCD}|n>=E_n|n>$ where\n$E_n$ is the energy of the hadron. However, in this paper we find $H_{\\rm\nQCD}|n>\\neq E_n|n>$ because the QCD hamiltonian $H_{QCD}$ is unphysical but the\n$E_n$ and $|n>$ of the hadron are physical. We show that this is consistent\nwith $E_{\\rm QCD}(t)=<n|H_{QCD}|n>\\neq E_n$ due to non-zero energy flux $E_{\\rm\nflux}(t)$ in QCD because of confinement involving non-perturbative QCD. Hence\nwe find that the lattice QCD method to study hadron mass is not correct."
    },
    {
        "anchor": "Data storage issues in lattice QCD calculations: I describe some of the data management issues in lattice Quantum\nChromodynamics calculations. I focus on the experience of the UKQCD\ncollaboration. I describe an attempt to use a relational database to store part\nof the data produced by a lattice QCD calculation.",
        "positive": "Connecting the Quenched and Unquenched Worlds via the Large N_c World: In the large N_c(number of colors) limit, quenched QCD and QCD are identical.\nThis implies that, in the effective field theory framework, some of the low\nenergy constants in (N_c=3) quenched QCD and QCD are the same up to\nhigher-order corrections in the 1/N_c expansion. Thus the calculation of the\nnonleptonic kaon decays relevant for the Delta I=1/2 rule in the quenched\napproximation is expected to differ from the unquenched one by an O(1/N_c)\ncorrection. However, the calculation relevant to the CP-violation parameter\nepsilon'/epsilon would have a relatively big higher-order correction due to the\nlarge cancellation in the leading order. Some important weak matrix elements\nare poorly known that even constraints with 100% errors are interesting. In\nthose cases, quenched calculations will be very useful."
    },
    {
        "anchor": "Relevant energy scale of color confinement from lattice QCD: We propose a new lattice framework to extract the relevant gluonic energy\nscale of QCD phenomena which is based on a \"cut\" on link variables in momentum\nspace. This framework is expected to be broadly applicable to all lattice QCD\ncalculations. Using this framework, we quantitatively determine the relevant\nenergy scale of color confinement, through the analyses of the quark-antiquark\npotential and meson masses. The relevant energy scale of color confinement is\nfound to be below 1.5 GeV in the Landau gauge. In fact, the string tension is\nalmost unchanged even after cutting off the high-momentum gluon component above\n1.5 GeV. When the relevant low-energy region is cut, the quark-antiquark\npotential is approximately reduced to a Coulomb-like potential, and each meson\nbecomes a quasi-free quark pair. As an analytical model calculation, we also\ninvestigate the dependence of the Richardson potential on the cut, and find the\nconsistent behavior with the lattice result.",
        "positive": "Renormalization constants of overlap quark bilinear operators from\n  RI/MOM and RI/SMOM scheme: We calculate the renormalization constants (RCs) of vector, axial, vector\nscalar, pseudoscalar and tensor quark operators of the overlap valence fermion,\non the 11 gauge ensembles with dynamical fermion using either Domain wall\nfermion~(DWF) action orHighly improved stagger quark~(HISQ) action at lattice\nspacings from 0.04 fm to 0.20 fm. We find the results under the\n$\\overline{\\text{MS}}$ scheme using either the RI/MOM or RI/SMOM scheme are\nconsistent with each other, once the proper $a^2p^2$ extrapolation is applied\nand the systematic uncertainties are estimated cautiously. Our results with\ndifferent gauge and fermion actions also indicate that the RCs are majorly\ndependent on the lattice spacing (as the inverse of UV cut-off) rather than the\nbare gauge coupling used by the gauge action."
    },
    {
        "anchor": "Tuning the generalized Hybrid Monte Carlo algorithm: We discuss the analytic computation of autocorrelation functions for the\ngeneralized Hybrid Monte Carlo algorithm applied to free field theory and\ncompare the results with numerical results for the $O(4)$ spin model in two\ndimensions. We explain how the dynamical critical exponent $z$ for some\noperators may be reduced from two to one by tuning the amount of randomness\nintroduced by the updating procedure, and why critical slowing down is not a\nproblem for other operators.",
        "positive": "Sign problem in $Z_3$-symmetric effective Polyakov-line model: As an effective model corresponding to $Z_3$-symmetric QCD ($Z_3$-QCD), we\nconstruct a $Z_3$-symmetric effective Polyakov-line model ($Z_3$-EPLM) by using\nthe logarithmic fermion effective action. Since $Z_3$-QCD tends to QCD in the\nzero temperature limit, $Z_3$-EPLM also agrees with the ordinary effective\nPolyakov-line model (EPLM) there; note that ordinary EPLM does not possess\n$Z_3$ symmetry. Our main purpose is to discuss a sign problem appearing in\n$Z_3$-EPLM. The action of $Z_3$-EPLM is real, when the Polyakov line is not\nonly real but also its $Z_3$ images. This suggests that the sign problem\nbecomes milder in $Z_3$-EPLM than in EPLM. In order to confirm this suggestion,\nwe do lattice simulations for both EPLM and $Z_3$-EPLM by using the reweighting\nmethod with the phase quenched approximation. In the low-temperature region,\nthe sign problem is milder in $Z_3$-EPLM than in EPLM. We also propose a new\nreweighting method. This makes the sign problem very weak in $Z_3$-EPLM."
    },
    {
        "anchor": "Manifestations of the axial anomaly in finite temperature QCD: We compute the flavor singlet meson correlators and screening masses in\nquenched and $N_f=2$ QCD at $N_t=8$. The consequences of our results for the\nrealization of the $U_A(1)$ symmetry at finite T are discussed and an\ninterpretation of our measurements in terms of the behaviour of the low lying\nfermionic modes is proposed.",
        "positive": "Many flavor QCD with N_f=12 and 16: Information of the phase structure of many flavor SU(3) gauge theory is of\ngreat interest for finding a theory which dynamically breaks the electro-weak\nsymmetry. We study the SU(3) gauge theory with fermions for $N_f=12$ and 16 in\nfundamental representation. Both of them, through perturbation theory, reside\nin the conformal phase. We try to determine the phase of each theory\nnon-perturbatively with lattice simulation and to find the characteristic\nbehavior of the physical quantities in the phase. HISQ type staggered fermions\nare used to reduce the discretization error which could compromise the behavior\nof the physical quantity to determine the phase structure at non-zero lattice\nspacings. Spectral quantities such as bound state masses of meson channel and\nmeson decay constants are investigated with careful finite volume analysis. Our\ndata favor the conformal over chiral symmetry breaking scenario for both\n$N_f=12$ and 16."
    },
    {
        "anchor": "Plaquette expectation value and lattice free energy of three-dimensional\n  SU(N) gauge theory: We use high precision lattice simulations to calculate the plaquette\nexpectation value in three-dimensional SU(N) gauge theory for N=2,3,4,5,8.\nUsing these results, we study the N-dependence of the first non-perturbative\ncoefficient in the weak-coupling expansion of hot QCD. We demonstrate that, in\nthe limit of large N, the functional form of the plaquette expectation value\nwith ultraviolet divergences subtracted is 15.9(2)-44(2)/N^2.",
        "positive": "QCD $\u03b2$ Function with Two Flavors of Dynamical Wilson Fermions: We test the asymptotic scaling behavior of state-of-the-art simulations of\nQCD with two flavors of light Wilson fermions. This is done by matching $\\pi$\nand $\\rho$ masses on lattices of size $16^3\\times32$ and $8^3\\times16$. We find\nthat at $\\beta=6/g^2=5.3$ matching is not possible over a range extending down\nto $\\beta=3.5$. The large lattice data at $\\beta=5.5$ matches the small lattice\nvalues at $\\beta=4.9(1)$ leading to a shift $\\Delta\\beta=0.6(1)$, considerably\nlarger than the perturbative prediction of $0.45$. In both cases we conclude\nthat the simulations are very far from the asymptotic scaling region."
    },
    {
        "anchor": "Domain Wall Fermion Simulations with the Exact One-Flavor Algorithm: As algorithmic developments have driven down the cost of simulating\ndegenerate light quark flavors the relative cost of simulating single quark\nflavors with the Rational Hybrid Monte Carlo (RHMC) algorithm has become more\nexpensive. TWQCD has proposed an exact one-flavor algorithm (EOFA) that allows\nfor HMC simulations of a single quark flavor without taking a square root of\nthe fermion determinant. We have independently implemented EOFA in the Columbia\nPhysics System (CPS) and BAGEL Fermion Sparse-Matrix Library (BFM) for Shamir\nand M\\\"{o}bius domain wall fermions, and begun to optimize and test our\nimplementation against RHMC. In this talk we discuss the derivation of the EOFA\naction, our tests of its equivalence to RHMC, and the current state of our\nimplementation and optimization. We find, after introducing a novel\npreconditioning technique for the EOFA Dirac operator, that EOFA is a factor of\n2.4 times faster than RHMC per molecular dynamics trajectory for the strange\nquark determinant on an $N_{f} = 2+1$ M\\\"{o}bius DWF ensemble with physical\nquark masses and a $24^{3} \\times 64 \\times 24$ volume. We expect that further\nimprovement is possible by retuning the integrator parameters for EOFA and by\ncontinuing to optimize our code.",
        "positive": "The Structure of Projected Center Vortices in Lattice Gauge Theory: We investigate the structure of center vortices in maximal center gauge of\nSU(2) lattice gauge theory at zero and finite temperature. In center projection\nthe vortices (called P-vortices) form connected two dimensional surfaces on the\ndual four-dimensional lattice. At zero temperature we find, in agreement with\nthe area law behaviour of Wilson loops, that most of the P-vortex plaquettes\nare parts of a single huge vortex. Small P-vortices, and short-range\nfluctuations of the large vortex surface, do not contribute to the string\ntension. All of the huge vortices detected in several thousand field\nconfigurations turn out to be unorientable. We determine the Euler\ncharacteristic of these surfaces and find that they have a very irregular\nstructure with many handles. At finite temperature P-vortices exist also in the\ndeconfined phase. They form cylindric objects which extend in time direction.\nAfter removal of unimportant short range fluctuations they consist only of\nspace-space plaquettes, which is in accordance with the perimeter law behaviour\nof timelike Wilson loops, and the area law behaviour of spatial Wilson loops in\nthis phase."
    },
    {
        "anchor": "A surprise with many-flavor staggered fermions in the strong coupling\n  limit: It is widely believed that chiral symmetry is spontaneously broken at zero\ntemperature in the strong coupling limit of staggered fermions, for any number\nof colors and flavors. Using Monte Carlo simulations, we show that this\nconventional wisdom, based on a mean-field analysis, is wrong. For sufficiently\nmany fundamental flavors, chiral symmetry is restored via a bulk, first-order\ntransition. This chirally symmetric phase appears to be analytically connected\nwith the expected conformal window of many-flavor continuum QCD. We perform\nsimulations in the chirally symmetric phase at zero quark mass for various\nsystem sizes L, and measure the torelon mass and the Dirac spectrum. We find\nthat all observables scale with L, which is hence the only infrared length\nscale. Thus, the strong-coupling chirally restored phase appears as a\nconvenient laboratory to study IR-conformality. Finally, we present a\nconjecture for the phase diagram of lattice QCD as a function of the bare\ncoupling and the number of quark flavors.",
        "positive": "Computing hybrid static potentials at short quark-antiquark separations\n  from fine lattices in $SU(3)$ Yang-Mills theory: We compute hybrid static potentials in $SU(3)$ lattice Yang-Mills theory at\nshort quark-antiquark separations using four different small lattice spacings\nas small as $0.04\\,\\text{fm}$. The resulting static potentials are important,\ne.g. when studying heavy hybrid mesons in the Born-Oppenheimer approximation.\nWe also discuss and exclude possible systematic errors from topological\nfreezing, the finite lattice volume and glueball decays."
    },
    {
        "anchor": "Heavy-Light Mesons with Quenched Lattice NRQCD: Results on Decay\n  Constants: We present a quenched lattice calculation of heavy-light meson decay\nconstants, using non-relativistic (NRQCD) heavy quarks in the mass region of\nthe $b$ quark and heavier, and clover-improved light quarks. The NRQCD\nHamiltonian and the heavy-light current include the corrections at first order\nin the expansion in the inverse heavy quark mass. We study the dependence of\nthe decay constants on the heavy meson mass $M$, for light quarks with the tree\nlevel ($c_{SW}$ = 1), as well as the tadpole improved clover coefficient. We\ncompare decay constants from NRQCD with results from clover ($c_{SW}=1$) heavy\nquarks.\n  Having calculated the current renormalisation constant $Z_A$ in one-loop\nperturbation theory, we demonstrate how the heavy mass dependence of the\npseudoscalar decay constants changes after renormalisation. For the first time,\nwe quote a result for $f_B$ from NRQCD including the full one-loop matching\nfactors at $O(\\alpha/M)$.",
        "positive": "Complete supersymmetry on the lattice and a No-Go theorem: A simulation\n  with intact supersymmetries on the lattice: In this work a lattice formulation of a supersymmetric theory is proposed and\ntested that preserves the complete supersymmetry on the lattice. The results of\na one-dimensional nonperturbative simulation show the realization of the full\nsupersymmetry and the correct continuum limit of the theory. It is proven that\nthe violation of supersymmetry due to the absence of the Leibniz rule on the\nlattice can be amended only with a nonlocal derivative and nonlocal interaction\nterm. The fermion doubling problem is also discussed, which leads to another\nimportant source of supersymmetry breaking on the lattice. This problem is also\nsolved with a nonlocal realization."
    },
    {
        "anchor": "The large-N phase transition of lattice SU(N) gauge theories: We investigate the large-N phase transition of lattice SU(N) gauge theories\nin the Wilson formulation, by performing a Monte Carlo simulation of the\ntwisted Eguchi-Kawai model. A variant of the multicanonical algorithm allows a\ndetailed exploration of the phase transition and a precise determination of the\ntransition temperature.",
        "positive": "Tensor renormalization group study of (3+1)-dimensional $Z_2$\n  gauge-Higgs model at finite density: We investigate the critical endpoints of the (3+1)-dimensional $Z_2$\ngauge-Higgs model at finite density together with the (2+1)-dimensional one at\nzero density as a benchmark using the tensor renormalization group method. We\nfocus on the phase transition between the Higgs phase and the confinement phase\nat finite chemical potential along the critical end line. In the\n(2+1)-dimensional model, the resulting endpoint is consistent with a recent\nnumerical estimate by the Monte Carlo simulation. In the (3+1)-dimensional\ncase, however, the location of the critical endpoint shows disagreement with\nthe known estimates by the mean-field approximation and the Monte Carlo\nstudies. This is the first application of the tensor renormalization group\nmethod to a four-dimensional lattice gauge theory and a key stepping stone\ntoward the future investigation of the phase structure of the finite density\nQCD."
    },
    {
        "anchor": "Two and three loops computations of renormalization constants for\n  lattice QCD: Renormalization constants can be computed by means of Numerical Stochastic\nPerturbation Theory to two/three loops in lattice perturbation theory, both in\nthe quenched approximation and in the full (unquenched) theory. As a case of\nstudy we report on the computation of renormalization constants of the\npropagator for Wilson fermions. We present our unquenched (N_f=2) computations\nand compare the results with non perturbative determinations.",
        "positive": "QCD transition temperature: full staggered result: We conclude our investigations on the QCD cross-over transition temperatures\nwith 2+1 staggered flavours and one-link stout improvement. We extend our\nprevious two studies [Phys. Lett. B643 (2006) 46, JHEP 0906:088 (2009)] by\nchoosing even finer lattices (N_t=16) and we work again with physical quark\nmasses. These new results [for details see JHEP 1009:073,2010] support our\nearlier findings. We compare them with the published results of the hotQCD\ncollaboration. All these results are confronted with the predictions of the\nHadron Resonance Gas model and Chiral Perturbation Theory for temperatures\nbelow the transition region. Our results can be reproduced by using the\nphysical spectrum. The findings of the hotQCD collaboration can be recovered\nonly by using a distorted spectrum. This analysis provides a simple explanation\nfor the observed discrepancy in the transition T between our and the hotQCD\ncollaborations."
    },
    {
        "anchor": "Phase diagram of two-dimensional SU($N$) super-Yang--Mills theory with\n  four supercharges: We non-perturbatively study two-dimensional SU($N$) supersymmetric\nYang--Mills theory with four supercharges and large $12 \\leq N \\leq 20$.\nAlthough this theory has no known holographic dual, we conduct numerical\ninvestigations to check for features similar to the sixteen-supercharge theory,\nwhich has a well-defined gravity dual. We carry out lattice field theory\ncalculations to determine the phase diagram, observing a spatial deconfinement\ntransition, similar to the maximally supersymmetric case. However, the\ntransition does not continue to strong couplings, implying the absence of a\nholographic interpretation for this four-supercharge theory.",
        "positive": "Dirac Eigenvalue Spectrum at Finite Temperature Using Domain Wall\n  Fermions: We present a study of the Dirac eigenvalue spectrum near the region of the\nQCD phase transition. This study makes use of a sequence of ensembles with\ntemperatures from 150 MeV to 200 MeV generated with $2 + 1$ flavors of\ndynamical domain wall fermions (DWF) and the dislocation sup- pressing\ndeterminant ratio (DSDR) action on a $16^3\\times 8$ lattice with an extent of\n32 or 48 in the fifth dimension. All the simulations lie on a line of constant\nphysics with 200 MeV pions. The DWF Dirac operator is normalized using the\nmethods of Giusti and Luscher combined with those of Rome-Southampton\ncollaboration, allowing a direct evaluation of the Banks-Casher relation. The\nrelation between the resulting temperature-dependent Dirac eigenvalue spectrum\nand the possible restoration of $U(1)_A$ symmetry with increasing temperature\nis discussed."
    },
    {
        "anchor": "Chiral extrapolations for nucleon magnetic moments: Lattice QCD simulations have made significant progress in the calculation of\nnucleon electromagnetic form factors in the chiral regime in recent years. With\nsimulation results achieving pion masses of order ~180 MeV, there is an\napparent challenge as to how the physical regime is approached. By using\ncontemporary methods in chiral effective field theory, both the quark-mass and\nfinite-volume dependence of the isovector nucleon magnetic moment are carefully\nexamined. The extrapolation to the physical point yields a result that is\ncompatible with experiment, albeit with a combined statistical and systematic\nuncertainty of 10%. The extrapolation shows a strong finite-volume dependence;\nlattice sizes of L > 5 fm must be used to simulate results within 2% of the\ninfinite-volume result for the magnetic moment at the physical pion mass.",
        "positive": "2-dimensional Regge gravity in the conformal gauge: By restricting the functional integration to the Regge geometries, we give\nthe discretized version of the well known path integral formulation of\n2--dimensional quantum gravity in the conformal gauge. We analyze the role\nplayed by diffeomorphisms in the Regge framework and we give an exact\nexpression for the Faddeev--Popov determinant related to a Regge surface; such\nan expression in the smooth limit goes over to the correct continuum result."
    },
    {
        "anchor": "Heavy quark potential at finite imaginary chemical potential: We investigate chemical-potential ($\\mu$) dependence of the static-quark free\nenergies in both the real and imaginary $\\mu$ regions, using the\nclover-improved two-flavor Wilson fermion action and the renormalization-group\nimproved Iwasaki gauge action. Static-quark potentials are evaluated from\nPolyakov-loop correlators in the deconfinement phase and the imaginary\n$\\mu=i\\mu_{\\rm I}$ region and extrapolated to the real $\\mu$ region with\nanalytic continuation. As the analytic continuation, the potential calculated\nat imaginary $\\mu=i\\mu_{\\rm I}$ is expanded into a Taylor-expansion series of\n$i\\mu_{\\rm I}/T$ up to 4th order and the pure imaginary variable $i\\mu_{\\rm\nI}/T$ is replaced by the real one $\\mu_{\\rm R}/T$. At real $\\mu$, the 4th-order\nterm weakens $\\mu$ dependence of the potential sizably. Also, the color-Debye\nscreening mass is extracted from the color-singlet potential at imaginary\n$\\mu$, and the mass is extrapolated to real $\\mu$ by analytic continuation. The\nscreening mass thus obtained has stronger $\\mu$ dependence than the prediction\nof the leading-order thermal perturbation theory at both real and imaginary\n$\\mu$.",
        "positive": "A novel density of state method for complex action systems: Recently, a new and efficient algorithm (the LLR method) has been proposed\nfor computing densities of states in statistical systems and gauge theories. In\nthis talk, we explore whether this novel density of states method can be\napplied to numerical computations of observables in systems for which the\naction is complex. To this purpose, we introduce a generalised density of\nstates, in terms of which integrals of oscillating observables can be\ndetermined semi-analytically, and we define a strategy to compute it with the\nLLR method. As a case study, we apply these ideas to the Z(3) spin model at\nfinite density, finding a remarkable agreement of our results for the phase\ntwist with those obtained with the worm algorithm for all explored chemical\npotentials, including values for which there are cancellations over sixteen\norders of magnitude. These findings open new perspectives for dealing with the\nsign problem on physically more relevant systems."
    },
    {
        "anchor": "K\u00e4ll\u00e9n-Lehmann spectroscopy for (un)physical degrees of freedom: We consider the problem of \"measuring\" the K\\\"all\\'en-Lehmann spectral\ndensity of a particle (be it elementary or bound state) propagator by means of\n4d lattice data. As the latter are obtained from operations at (Euclidean\nmomentum squared) p^2>=0, we are facing the generically ill-posed problem of\nconverting a limited data set over the positive real axis to an integral\nrepresentation, extending over the whole complex p^2-plane. We employ a linear\nregularization strategy, commonly known as the Tikhonov method with Morozov\ndiscrepancy principle, with suitable adaptations to realistic data, e.g. with\nunknown threshold. An important virtue over the (standard) maximum entropy\nmethod is the possibility to also probe unphysical spectral densities, as, for\nexample, of a confined gluon. We apply our proposal here to \"physical\" mock\nspectral data as a litmus test and then to the lattice SU(3) Landau gauge gluon\nat zero temperature.",
        "positive": "Lattice Gauge Theories and Spin Models: The Wegner $Z_2$ gauge theory-$Z_2$ Ising spin model duality in $(2+1)$\ndimensions is revisited and derived through a series of canonical\ntransformations. The Kramers-Wannier duality is similarly obtained. The Wegner\n$Z_2$ gauge-spin duality is directly generalized to SU(N) lattice gauge theory\nin $(2+1)$ dimensions to obtain the SU(N) spin model in terms of the SU(N)\nmagnetic fields and their conjugate SU(N) electric scalar potentials. The exact\nand complete solutions of the $Z_2, U(1), SU(N)$ Gauss law constraints in terms\nof the corresponding spin or dual potential operators are given. The gauge-spin\nduality naturally leads to a new gauge invariant magnetic disorder operator for\nSU(N) lattice gauge theory which produces a magnetic vortex on the plaquette. A\nvariational ground state of the SU(2) spin model with nearest neighbor\ninteractions is constructed to analyze SU(2) gauge theory."
    },
    {
        "anchor": "The B -> D* l nu form factor at zero recoil from three-flavor lattice\n  QCD: A model independent determination of |V_cb|: We present the first lattice QCD calculation of the form factor for B-> D* l\nnu with three flavors of sea quarks. We use an improved staggered action for\nthe light valence and sea quarks (the MILC configurations), and the Fermilab\naction for the heavy quarks. The form factor is computed at zero recoil using a\nnew double ratio method that yields the form factor more directly than the\nprevious Fermilab method. Other improvements over the previous calculation\ninclude the use of much lighter light quark masses, and the use of lattice\n(staggered) chiral perturbation theory in order to control the light quark\ndiscretization errors and chiral extrapolation. We obtain for the form factor,\nF_{B-> D*}(1)=0.921(13)(20), where the first error is statistical and the\nsecond is the sum of all systematic errors in quadrature. Applying a 0.7%\nelectromagnetic correction and taking the latest PDG average for F_{B->\nD*}(1)|V_cb| leads to |V_cb|=(38.7 +/- 0.9_exp +/- 1.0_theo) x 10^-3.",
        "positive": "On the effects of heavy sea quarks at low energies: We present a factorisation formula for the dependence of light hadron masses\nand low energy hadronic scales on the mass $M$ of a heavy quark: apart from an\noverall factor $Q$, ratios such as $r_0(M)/r_0(0)$ are computable in\nperturbation theory at large $M$. The mass-independent factor $Q$ is obtained\nfrom the theory in the limit $M\\to0$ and the decoupled theory with the heavy\nquark removed. The perturbation theory part is stable concerning different loop\norders and our non-perturbative results match on quantitatively to the\nperturbative prediction.\n  Upon taking ratios of different hadronic scales at the same mass, the\nperturbative function drops out and the ratios are given by the decoupled\ntheory up to $M^{-2}$ corrections. Our present numerical results are obtained\nin a model calculation where there are no light quarks and a heavy doublet of\nquarks is decoupled. They are limited to masses a factor two below the charm.\nThis is not large enough to see the $M^{-2}$ scaling predicted by the theory,\nbut it is sufficient to verify - in the continuum limit - that the sea quark\neffects of quarks with masses around the charm mass are very small."
    },
    {
        "anchor": "Lattice Chiral Gauge Theories in a Renormalizable Gauge: The lattice formulation of gauge theories in a renormalizable gauge is\ndiscussed. The formulation invokes a new phase diagram, and it may allow for a\nlattice definition of Chiral Gauge Theories.",
        "positive": "Critical properties of the Z(3) interface in (2+1)-D SU(3) gauge theory: We study the interface between two different Z(3) vacua in the deconfined\nphase of SU(3) pure gauge theory in 2+1 dimensions just above the critical\ntemperature. In simulations of the Euclidean lattice gauge theory formulation\nof the system we measure the fluctuations of the interface as the critical\ntemperature is approached and as a function of system size. We show that the\nintrinsic width of the interface remains small even very close to the critical\ntemperature. Some dynamical exponents which govern the interaction of the\ninterface with our Monte Carlo algorithm are also estimated. We conclude that\nthe Z(3) interface has properties broadly similar to those in many other\ncomparable statistical mechanical systems."
    },
    {
        "anchor": "Flux tubes in the SU(3) vacuum: London penetration depth and coherence\n  length: Within the dual superconductor scenario for the QCD confining vacuum, the\nchromoelectric field generated by a static $q\\overline{q}$ pair can be fitted\nby a function derived, by dual analogy, from a simple variational model for the\nmagnitude of the normalized order parameter of an isolated Abrikosov vortex.\nPrevious results for the SU(3) vacuum are revisited, but here the transverse\nchromoelectric field is measured by means of the connected correlator of two\nPolyakov loops and, in order to reduce noise, the smearing procedure is used\ninstead of cooling. The penetration and coherence lengths of the flux tube are\nthen extracted from the fit and compared with previous results.",
        "positive": "Physics prospects of UV-filtered overlap quarks: Some key features of the overlap operator with a UV-filtered Wilson kernel\nare discussed. The first part concerns spectral properties of the underlying\nshifted hermitean Wilson operator and the relation to the observed speedup of\nthe overlap construction. Next, the localization of the filtered overlap and\nits axial-vector renormalization constant are discussed. Finally, results of an\nexploratory scaling study for $m_{ud}, m_s$ and $f_\\pi, f_K$ are presented."
    },
    {
        "anchor": "Implementation of the HMC algorithm on the tempered Lefschetz thimble\n  method: The tempered Lefschetz thimble method (TLTM) is a parallel-tempering\nalgorithm towards solving the numerical sign problem, where the system is\ntempered by the antiholomorphic gradient flow to tame both the sign and\nergodicity problems simultaneously. In this paper, we implement the hybrid\nMonte Carlo (HMC) algorithm for transitions on each flowed surface, expecting\nthat this implementation on TLTM will give a useful framework for future\ncomputations of large-scale systems including fermions. Although the use of HMC\nin Lefschetz thimble methods has been proposed so far, our crucial achievement\nhere is that HMC is implemented on TLTM so as to work within the\nparallel-tempering algorithm in TLTM, especially by developing an algorithm to\nhandle zeros of fermion determinants in the course of the molecular-dynamics\nprocess. We confirm that the algorithm works correctly by applying it to the\nsign problem of the Hubbard model on a small lattice, for which the TLTM is\nknown to work with the Metropolis algorithm. We show that the use of HMC\nsignificantly reduces the autocorrelation times with less computational times\ncompared to the Metropolis algorithm.",
        "positive": "Evidence for O(2) universality at the finite temperature transition for\n  lattice QCD with 2 flavours of massless staggered quarks: We simulate lattice QCD with 2 flavours of massless quarks on lattices of\ntemporal extent N_t=8, to study the finite temperature transition from hadronic\nmatter to a quark-gluon plasma. A modified action which incorporates an\nirrelevant chiral 4-fermion interaction is used, which allows simulations at\nzero quark mass. We obtain excellent fits of the chiral condensates to the\nmagnetizations of a 3-dimensional O(2) spin model on lattices small enough to\nmodel the finite size effects. This gives predictions for correlation lengths\nand chiral susceptibilities from the corresponding spin-model quantities. These\nare in good agreement with our measurements over the relevant range of\nparameters. Binder cumulants are measured, but the errors are too large to draw\ndefinite conclusions. From the properties of the O(2) spin model on the\nrelatively small lattices with which we fit our `data', we can see why earlier\nattempts to fit staggered lattice data to leading-order infinite-volume scaling\nfunctions, as well as finite size scaling studies, failed and led to erroneous\nconclusions."
    },
    {
        "anchor": "String-like behaviour of 4d SU(3) Yang-Mills flux tubes: We present here results on the fine structure of the static q\\bar q potential\nin d=4 SU(3) Yang-Mills theory. The potential is obtained from Polyakov loop\ncorrelators having separations between 0.3 and 1.2 fermi. Measurements were\ncarried out on lattices of spatial extents of about 4 and 5.4 fermi. The\ntemporal extent was 5.4 fermi in both cases. The results are analyzed in terms\nof the force between a q\\bar q pair as well as in terms of a scaled second\nderivative of the potential. The data is accurate enough to distinguish between\ndifferent effective string models and it seems to favour the expression for\nground state energy of a Nambu-Goto string.",
        "positive": "New Lower Bounds on the Self-Avoiding-Walk Connective Constant: We give an elementary new method for obtaining rigorous lower bounds on the\nconnective constant for self-avoiding walks on the hypercubic lattice $Z^d$.\nThe method is based on loop erasure and restoration, and does not require exact\nenumeration data. Our bounds are best for high $d$, and in fact agree with the\nfirst four terms of the $1/d$ expansion for the connective constant. The bounds\nare the best to date for dimensions $d \\geq 3$, but do not produce good results\nin two dimensions. For $d=3,4,5,6$, respectively, our lower bound is within\n2.4\\%, 0.43\\%, 0.12\\%, 0.044\\% of the value estimated by series extrapolation."
    },
    {
        "anchor": "Single-Cluster Monte Carlo Study of the Ising Model on Two-Dimensional\n  Random Lattices: We use the single-cluster Monte Carlo update algorithm to simulate the Ising\nmodel on two-dimensional Poissonian random lattices with up to 80,000 sites\nwhich are linked together according to the Voronoi/Delaunay prescription. In\none set of simulations we use reweighting techniques and finite-size scaling\nanalysis to investigate the critical properties of the model in the very\nvicinity of the phase transition. In the other set of simulations we study the\napproach to criticality in the disordered phase, making use of improved\nestimators for measurements. From both sets of simulations we obtain clear\nevidence that the critical exponents agree with the exactly known exponents for\nregular lattices, i.e., that (lattice) universality holds for the\ntwo-dimensional Ising model.",
        "positive": "Nonperturbative tuning of an improved relativistic heavy-quark action\n  with application to bottom spectroscopy: We calculate the masses of bottom mesons using an improved relativistic\naction for the b-quarks and the RBC/UKQCD Iwasaki gauge configurations with 2+1\nflavors of dynamical domain-wall light quarks. We analyze configurations with\ntwo lattice spacings: a^{-1} = 1.729 GeV (a ~ 0.11 fm) and a^{-1} = 2.281 GeV\n(a ~ 0.086 fm). We use an anisotropic, clover-improved Wilson action for the\nb-quark, and tune the three parameters of the action nonperturbatively such\nthat they reproduce the experimental values of the B_s and B_s* heavy-light\nmeson states. The masses and mass-splittings of the low-lying bottomonium\nstates (such as the eta_b and Upsilon) can then be computed with no additional\ninputs, and comparison between these predictions and experiment provides a test\nof the validity of our method. We obtain bottomonium masses with total\nuncertainties of ~0.5-0.6% and fine-structure splittings with uncertainties of\n~35-45%; for all cases we find good agreement with experiment. The parameters\nof the relativistic heavy-quark action tuned for b-quarks presented in this\nwork can be used for precise calculations of weak matrix elements such as\nB-meson decay constants and mixing parameters with lattice discretization\nerrors that are of the same size as in light pseudoscalar meson quantities.\nThis general method can also be used for charmed meson masses and matrix\nelements if the parameters of the heavy-quark action are appropriately tuned."
    },
    {
        "anchor": "The (2+1)-dimensional Gross-Neveu model with a U(1) chiral symmetry at\n  non-zero temperature: We present results from numerical simulations of the (2+1)-dimensional\nGross-Neveu model with a U(1) chiral symmetry and N_f=4 fermion species at\nnon-zero temperature. We provide evidence that there are two different chirally\nsymmetric phases, one critical and one with finite correlation length,\nseparated by a Berezinskii-Kosterlitz-Thouless transition. We have also\nidentified a regime above the critical temperature in which the fermions\nacquire a screening mass even in the absence of chiral symmetry breaking,\nanalogous to the pseudogap behaviour observed in cuprate superconductors.",
        "positive": "On the chiral anomaly and the Yang-Mills gradient flow: There are currently two singularity-free universal expressions for the\ntopological susceptibility in QCD, one based on the Yang-Mills gradient flow\nand the other on density-chain correlation functions. While the latter link the\nsusceptibility to the anomalous chiral Ward identities, the gradient flow\npermits the emergence of the topological sectors in lattice QCD to be\nunderstood. Here the two expressions are shown to coincide in the continuum\ntheory, for any number of quark flavours in the range where the theory is\nasymptotically free."
    },
    {
        "anchor": "Thermodynamics with 2+1 and 3 Flavors of Improved Staggered Quarks: We present preliminary results from exploring the phase diagram of finite\ntemperature QCD with three degenerate flavors and with two light flavors and\nthe mass of the third held approximately at the strange quark mass. We use an\norder $\\alpha_s^2 a^2, a^4$ Symanzik improved gauge action and an order\n$\\alpha_s a^2, a^4$ improved staggered quark action. The improved staggered\naction leads to a dispersion relation with diminished lattice artifacts, and\nhence better thermodynamic properties. It decreases the flavor symmetry\nbreaking of staggered quarks substantially, and we estimate that at the\ntransition temperature for an $N_t=8$ to $N_t=10$ lattice {\\em all} pions will\nbe lighter than the lightest kaon. Preliminary results on lattices with\n$N_t=4$, 6 and 8 are presented.",
        "positive": "On ambiguities of sign determination of the S-matrix from energy levels\n  in a finite box: In a recent paper the authors make a study on the determination of the\nS-matrix elements for scattering of particles in the infinite volume from the\nenergy levels in the finite box for the case of multiple channels. The study is\ndone with a toy model in 1+1 dimension and the authors find that there is some\nambiguity in the sign of nondiagonal matrix elements, casting doubts on whether\nthe needed observables in the infinite volume can be obtained from the energy\nlevels of the box. In this paper I present an easy derivation, confirming the\nambiguity of the sign and argue that this, however, does not put restrictions\nin the determination of observables."
    },
    {
        "anchor": "Tensor-network simulation of the strong-coupling $U(N)$ model: We apply tensor network methods to study the strong-coupling $U(N)$ model in\nits dimer formulation. In three and four dimensions, we investigate the chiral\ncondensate as a function of the quark mass and the degree of the symmetry\ngroup, and find good agreement with Monte Carlo simulations. Particularly\ninteresting is the study of chiral symmetry breaking as a function of the mass\nand the volume, which clearly shows that this symmetry is spontaneously broken\nin the limit of infinite volume and zero mass.",
        "positive": "Perturbative computation in a QED$_3$-inspired conformal abelian gauge\n  model on the lattice: We perform perturbative computations in a lattice gauge theory with a\nconformal measure that is quadratic in a non-compact abelian gauge field and is\nnonlocal, as inspired by the induced gauge action in massless QED$_3$. In a\nprevious work, we showed that coupling fermion sources to the gauge model led\nto nontrivial conformal data in the correlation functions of fermion bilinears\nthat are functions of charge $q$ of the fermion. In this paper, we compute such\ngauge invariant fermionic observables to order $q^2$ in lattice perturbation\ntheory with the same conformal measure. We reproduce the expectations for\nscalar anomalous dimension from previous estimates in dimensional\nregularization. We address the issue of the lattice regulator dependence of the\namplitudes of correlation functions."
    },
    {
        "anchor": "Monopole-antimonopole condensation in the interpolating Georgi-Glashow\n  model: We study the three dimensional Georgi-Glashow model (which interpolates\nsmoothly between pure U(1) and SU(2) limits) using a constrained cooling which\npreserves 't Hooft-Polyakov monopoles. We find that the monopole-antimonopole\ncondensation gives an area law for the Wilson loops. The monopole contribution\nto the string tension is close to the Monte Carlo value in the intermediate\nregion.",
        "positive": "Backward running or absence of running from Creutz ratios: We extract the running coupling based on Creutz ratios in SU(2) lattice gauge\ntheory with two Dirac fermions in the adjoint representation. Depending on how\nthe extrapolation to zero fermion mass is performed, either backward running or\nan absence of running is observed at strong bare coupling. This behavior is\nconsistent with other findings which indicate that this theory has an infrared\nfixed point."
    },
    {
        "anchor": "Once more on the interrelation between Abelian monopoles and P-vortices\n  in SU(2) LGT: We study the properties of configurations from which P-vortices on one hand\nor Abelian monopoles on the other hand have been removed. We confirm the loss\nof confinement in both cases and investigate in what respect the modified\nensembles differ from the confining ones from the point of view of the\ncomplementary confinement scenario.",
        "positive": "Symmetries and exponential error reduction in YM theories on the\n  lattice: theoretical aspects and simulation results: The path integral of a quantum system with an exact symmetry can be written\nas a sum of functional integrals each giving the contribution from quantum\nstates with definite symmetry properties. We propose a strategy to compute each\nof them, normalized to the one with vacuum quantum numbers, by a Monte Carlo\nprocedure whose cost increases power-like with the time extent of the lattice.\nThis is achieved thanks to a multi-level integration scheme, inspired by the\ntransfer matrix formalism, which exploits the symmetry and the locality in time\nof the underlying statistical system. As a result the cost of computing the\nlowest energy level in a given channel, its multiplicity and its matrix\nelements is exponentially reduced with respect to the standard path-integral\nMonte Carlo. We briefly illustrate the approach in the simple case of the\none-dimensional harmonic oscillator and discuss in some detail its extension to\nthe four-dimensional Yang Mills theories. We report on our recent new results\nin the SU(3) Yang--Mills theory on the relative contribution to the partition\nfunction of the parity-odd states."
    },
    {
        "anchor": "The Coulomb-Higgs phase transition in Z(8) and q=8 U(1)-Higgs models: The Coulomb-Higgs phase transition of the four dimensional Z$_8$ gauge model\nis studied. We find clear first order properties in contradiction with the\npreviously stressed second order behavior. That transition point may be\nregarded as the end of a transition line of the U(1)-Higgs model with charge\n$q=8$, that has been also assumed of second order. We show that this line is\nfirst order in a wide region, with a decreasing latent heat that goes to zero\nwhen closing to the 4--$d$ XY model limit.",
        "positive": "Results for the mass difference between the long- and short- lived K\n  mesons for physical quark masses: The two neutral kaon states in nature, the $K_L$ (long-lived) and $K_S$\n(short-lived) mesons, are the two time-evolution eigenstates of the $K^0 -\n\\overline{K^0}$ mixing system. The prediction of their mass difference $\\Delta\nm_K$ based on the Standard Model is an important goal of lattice QCD. In this\narticle, I will present preliminary results from a calculation of $\\Delta m_K$\nperformed on an ensemble of $64^3 \\times 128$ gauge configurations with inverse\nlattice spacing of 2.36 GeV and physical quark masses. These new results come\nfrom 2.5 times the Monte Carlo statistics used for the result presented in last\nyear's conference. Further discussion of the methods employed and the resulting\nsystematic errors will be given."
    },
    {
        "anchor": "Universal low-temperature behavior of two-dimensional lattice scalar\n  chromodynamics: We study the role that global and local nonabelian symmetries play in\ntwo-dimensional lattice gauge theories with multicomponent scalar fields. We\nstart from a maximally O($M$)-symmetric multicomponent scalar model, Its\nsymmetry is partially gauged to obtain an SU($N_c$) gauge theory (scalar\nchromodynamics) with global U$(N_f)$ (for $N_c\\ge 3$) or Sp($N_f$) symmetry\n(for $N_c=2$), where $N_f>1$ is the number of flavors. Correspondingly, the\nfields belong to the coset $S^M$/SU($N_c$) where $S^M$ is the $M$-dimensional\nsphere and $M=2 N_f N_c$. In agreement with the Mermin-Wagner theorem, the\nsystem is always disordered at finite temperature and a critical behavior only\ndevelops in the zero-temperature limit. Its universal features are investigated\nby numerical finite-size scaling methods. The results show that the asymptotic\nlow-temperature behavior belongs to the universality class of the 2D\nCP$^{N_f-1}$ field theory for $N_c>2$, and to that of the 2D Sp($N_f$) field\ntheory for $N_c=2$. These universality classes correspond to 2D statistical\nfield theories associated with symmetric spaces that are invariant under\nSp($N_f$) transformations for $N_c=2$ and under SU($N_f$) for $N_c > 2$. These\nsymmetry groups are the same invariance groups of scalar chromodynamics, apart\nfrom a U(1) flavor symmetry that is present for $N_f \\ge N_c > 2$, which does\nnot play any role in determining the asymptotic behavior of the model.",
        "positive": "Three particle quantization condition in a finite volume: 2. general\n  formalism and the analysis of data: We derive the three-body quantization condition in a finite volume using an\neffective field theory in the particle-dimer picture. Moreover, we consider the\nextraction of physical observables from the lattice spectrum using the\nquantization condition. To illustrate the general framework, we calculate the\nvolume-dependent three-particle spectrum in a simple model both below and above\nthe three-particle threshold. The relation to existing approaches is discussed\nin detail."
    },
    {
        "anchor": "Beyond the Standard Model Kaon Mixing with Physical Masses: We present results from a calculation of beyond the standard model (BSM) kaon\nmixing including data physical with light quark masses. We simulate $N_f=2+1$\nQCD with Iwasaki gauge and domain wall fermion action on 8 ensembles, spanning\n3 lattice spacings and pion masses from the physical value up to 430MeV. The\nratio of the BSM to standard model (SM) matrix elements are extracted from the\ncorrelation functions and renormalised using the RI-SMOM Rome-Southampton\nmethod with non-exceptional kinematics. The results at the physical point\ncontinuum limit are found by performing a simultaneous continuum chiral\nextrapolation. In this work we gain consistency with our previous results and\nachieve a reduction in both the statistical and systematic error.",
        "positive": "Critical behavior of the compact 3d U(1) gauge theory on isotropic\n  lattices: We report on the computation of the critical point of the deconfinement phase\ntransition, critical indices and the string tension in the compact three\ndimensional U(1) lattice gauge theory at finite temperatures. The critical\nindices govern the behavior across the deconfinement phase transition in the\npure gauge U(1) model and are generally expected to coincide with the critical\nindices of the two-dimensional XY model. We studied numerically the U(1) model\nfor N_t=8 on lattices with spatial extension ranging from L=32 to L=256. Our\ndetermination of the infinite volume critical point on the lattice with N_t=8\ndiffers substantially from the pseudo-critical coupling at L=32, found earlier\nin the literature and implicitly assumed as the onset value of the deconfined\nphase. The critical index $\\nu$ computed from the scaling of the\npseudo-critical couplings with the extension of the spatial lattice agrees well\nwith the XY value $\\nu$=1/2. On the other hand, the index $\\eta$ shows large\ndeviation from the expected universal value. The possible reasons of such\nbehavior are discussed in details."
    },
    {
        "anchor": "SU(3) Landau gauge gluon and ghost propagators using the logarithmic\n  lattice gluon field definition: We study the Landau gauge gluon and ghost propagators of SU(3) gauge theory,\nemploying the logarithmic definition for the lattice gluon fields and\nimplementing the corresponding form of the Faddeev-Popov matrix. This is\nnecessary in order to consistently compare lattice data for the bare\npropagators with that of higher-loop numerical stochastic perturbation theory\n(NSPT). In this paper we provide such a comparison, and introduce what is\nneeded for an efficient lattice study. When comparing our data for the\nlogarithmic definition to that of the standard lattice Landau gauge we clearly\nsee the propagators to be multiplicatively related. The data of the associated\nghost-gluon coupling matches up almost completely. For the explored lattice\nspacings and sizes discretization artifacts, finite-size and Gribov-copy\neffects are small. At weak coupling and large momentum, the bare propagators\nand the ghost-gluon coupling are seen to be approached by those of higher-order\nNSPT.",
        "positive": "Some Analytical Results in (2+1) dimensional L.G.T.: We show that, within the framework of suitably chosen approximate effective\nactions it is possible to evaluate analytically the string tension, the\nspacelike string tension and the deconfinement temperature of (2+1) dimensional\nlattice gauge theories. In the case of SU(2) gauge theory our results agree\nwith those obtained through Montecarlo simulations."
    },
    {
        "anchor": "Finite volume study of electric polarizabilities from lattice QCD: Knowledge of the electric polarizability is crucial to understanding the\ninteractions of hadrons with electromagnetic fields. The neutron polarizability\nis very sensitive to the quark mass and is expected to diverge in the chiral\nlimit. Here we present results for the electric polarizability of the neutron,\nneutral pion, and neutral kaon on eight ensembles with nHYP-smeared clover\ndynamical fermions with two different pion masses (227 and 306 MeV). These are\ncurrently the lightest pion masses used in polarizability studies. For each\npion mass we compute the polarizability at four different volumes and perform\nan infinite volume extrapolation for the three hadrons. Along with the infinite\nvolume extrapolation we conduct a chiral extrapolation for the kaon\npolarizability to the physical point. We compare our results for the neutron\npolarizability to predictions from chiral perturbation theory.",
        "positive": "Mass Preconditioning for the Exact One-Flavor Action in Lattice QCD with\n  Domain-Wall Fermion: The mass-preconditioning (MP) technique has become a standard tool to enhance\nthe efficiency of the hybrid Monte-Carlo simulation (HMC) of lattice QCD with\ndynamical quarks, for 2-flavors QCD with degenerate quark masses, as well as\nits extension to the case of one-flavor by taking the square-root of the\nfermion determinant of 2-flavors with degenerate masses. However, for lattice\nQCD with domain-wall fermion, the fermion determinant of any single fermion\nflavor can be expressed as a functional integral with an exact pseudofermion\naction $ \\phi^\\dagger H^{-1} \\phi $, where $ H^{-1} $ is a positive-definite\nHermitian operator without taking square-root, and with the chiral structure\n\\cite{Chen:2014hyy}. Consequently, the mass-preconditioning for the exact\none-flavor action (EOFA) does not necessarily follow the conventional (old) MP\npattern. In this paper, we present a new mass-preconditioning for the EOFA,\nwhich is more efficient than the old MP which we have used in Refs.\n\\cite{Chen:2014hyy,Chen:2014bbc}. We perform numerical tests in lattice QCD\nwith $ N_f = 1 $ and $ N_f = 1+1+1+1 $ optimal domain-wall quarks, with one\nmass-preconditioner applied to one of the exact one-flavor actions, and we find\nthat the efficiency of the new MP is more than 20\\% higher than that of the old\nMP."
    },
    {
        "anchor": "Deformations of Boltzmann Distributions: Consider a one-parameter family of Boltzmann distributions $p_t(x) =\n\\tfrac{1}{Z_t}e^{-S_t(x)}$. This work studies the problem of sampling from\n$p_{t_0}$ by first sampling from $p_{t_1}$ and then applying a transformation\n$\\Psi_{t_1}^{t_0}$ so that the transformed samples follow $p_{t_0}$. We derive\nan equation relating $\\Psi$ and the corresponding family of unnormalized\nlog-likelihoods $S_t$. The utility of this idea is demonstrated on the $\\phi^4$\nlattice field theory by extending its defining action $S_0$ to a family of\nactions $S_t$ and finding a $\\tau$ such that normalizing flows perform better\nat learning the Boltzmann distribution $p_\\tau$ than at learning $p_0$.",
        "positive": "Minimally doubled fermions at one loop: Minimally doubled fermions have been proposed as a cost-effective realization\nof chiral symmetry at non-zero lattice spacing. Using lattice perturbation\ntheory at one loop, we study their renormalization properties. Specifically, we\ninvestigate the consequences of the breaking of hyper-cubic symmetry, which is\na typical feature of this class of fermionic discretizations. Our results for\nthe quark self-energy indicate that the four-momentum undergoes a\nrenormalization which contains a linearly divergent piece. We also compute\nrenormalization factors for quark bilinears, construct the conserved vector and\naxial-vector currents and verify that at one loop the renormalization factors\nof the latter are equal to one."
    },
    {
        "anchor": "Central and tensor Lambda-nucleon potentials from lattice QCD: We present our latest study of Lambda-Nucleon (LN) interaction by using\nlattice QCD, following up on our report at LATTICE 2008. We have calculated not\nonly the scattering lengths but also the central and tensor potentials, which\nare obtained from the Bethe-Salpeter (BS) amplitude measured in lattice QCD.\nFor these calculations, we employ two different types of gauge configurations:\n(i) 2+1 flavor full QCD configurations generated by the PACS-CS collaboration\nat $\\beta=1.9$ ($a=0.0907(13)$ fm) on a $32^3\\times 64$ lattice, whose spatial\nvolume is (2.90 fm)$^3$, with the quark masses corresponding to\n$(m_\\pi,m_K)\\approx (301,592)$, $(414,637)$, $(570,724)$ and $(699,787)$ (in\nunits of MeV). (ii) Quenched QCD configurations at $\\beta=5.7$ ($a=0.1416(9)$\nfm) on a $32^3\\times48$ lattice, whose spatial volume is (4.5 fm)$^3$, with the\nquark masses corresponding to $(m_\\pi,m_K)\\approx (512,606)$, $(464, 586)$ and\n$(407,565)$. The following qualitative features are found: The LN potential has\na relatively strong (weak) repulsive core in the $^1S_0$ ($^3S_1$) channel at\nshort distance, while the potential has slight attractive region at medium\ndistance. The tensor potential is found to be weaker than the $NN$ case. These\nresults hold in both full and quenched QCD. The energy of the ground state on\nthe finite lattice volume is calculated: In both spin channels, energy shift\ndue to the finite volume, from which we extract the scattering length via the\nL\\\"{u}scher's formula, is found to be negative at all values of quark masses,\nsuggesting that the LN interaction is attractive. We have also discussed the\nquark mass dependences of the potentials and the scattering lengths.",
        "positive": "Lattice QCD with light dynamical quarks: We report on the simulation of QCD with light dynamical quarks using the\ntwo-step multi-boson (TSMB) algorithm.\n  In an exploratory study with two flavours of quarks at lattice spacing about\n0.27 fm and with quark mass down to one sixth of the strange quark mass\neigenvalue spectra and autocorrelations have been studied.\n  Here we present results on the volume dependence as well as tests of possible\nalgorithmic improvements."
    },
    {
        "anchor": "Fermion Condensates in Two Colours Finite Density QCD at Strong Coupling: We study unquenched lattice SU(2) at nonzero chemical potential at strong\ncoupling and with eight flavours of Kogut-Susskind fermions. Introducing a\ndiquark source term we analyze the behaviour of different types of fermion\ncondensates. Using a non standard approach we can obtain results at zero\nexternal source without extrapolations. We find strong evidences for a (high\ndensity) second order phase transition where a diquark condensate appears. The\ncorresponding critical chemical potential is in good agreement with half the\npion mass.",
        "positive": "External magnetic fields in gauge theories: A general discussion is presented of the response of a gauge-field system to\nexternal magnetic fields, in the light of a theorem due to S. Elitzur. As a\nresult a natural understanding emerges of some recent puzzling results from\nlattice MC simulations, as well as of the phenomenon of ``perfect\ndiamagnetism'' of non-abelian gauge theories, discovered almost ten years ago."
    },
    {
        "anchor": "The Chroma Software System for Lattice QCD: We describe aspects of the Chroma software system for lattice QCD\ncalculations. Chroma is an open source C++ based software system developed\nusing the software infrastructure of the US SciDAC initiative. Chroma\ninterfaces with output from the BAGEL assembly generator for optimised lattice\nfermion kernels on some architectures. It can be run on workstations, clusters\nand the QCDOC supercomputer.",
        "positive": "Fermion Bags and A New Origin for a Fermion Mass: The fermion bag is a powerful idea that helps to solve fermion lattice field\ntheories using Monte Carlo methods. Some sign problems that had remained\nunsolved earlier can be solved within this framework. In this work we argue\nthat the fermion bag also gives insight into a new mechanism of fermion mass\ngeneration, especially at strong couplings where fermion masses are related to\nthe fermion bag size. On the other hand, chiral condensates arise due to zero\nmodes in the Dirac operator within a fermion bag. Although in traditional\nfour-fermion models the two quantities seem to be related, we show that they\ncan be decoupled. While fermion bags become small at strong couplings, the\nability of zero modes of the Dirac operator within fermion bags to produce a\nchiral condensate, can be suppressed by the presence of additional zero modes\nfrom other fermions. Thus, fermions can become massive even without a chiral\ncondensate. This new mechanism of mass generation was discovered long ago in\nlattice field theory, but has remained unappreciated. Recent work suggests that\nit may be of interest even in continuum quantum field theory."
    },
    {
        "anchor": "Dark matter Search and the Scalar Quark Contents of the Nucleon: We present lattice QCD simulation results from the European Twisted Mass\nCollaboration (ETMC) for the light, strange and charm quark contents of the\nnucleon. These quantities are important ingredients to estimate the\ncross-section for the detection of WIMPs as Dark Matter candidates. By\nemploying a particular lattice QCD formulation, i.e. twisted mass fermions,\naccurate results of the light and strange scalar contents of the nucleon can be\nobtained. In addition, we provide a bound for the charm quark content of the\nnucleon.",
        "positive": "Signatures of S-wave bound-state formation in finite volume: We discuss formation of an S-wave bound-state in finite volume on the basis\nof L\\\"uscher's phase-shift formula.It is found that although a bound-state pole\ncondition is fulfilled only in the infinite volume limit, its modification by\nthe finite size corrections is exponentially suppressed by the spatial extent\n$L$ in a finite box $L^3$. We also confirm that the appearance of the S-wave\nbound state is accompanied by an abrupt sign change of the S-wave scattering\nlength even in finite volume through numerical simulations. This distinctive\nbehavior may help us to discriminate the loosely bound state from the lowest\nenergy level of the scattering state in finite volume simulations."
    },
    {
        "anchor": "Status of the Higgs Mass Bound: The status of the triviality bound of the Higgs mass in the Minimal Standard\nModel is reviewed. It is emphasized that the bound is obtained, in the scalar\nsector, by limiting cutoff effects on physical processes. Results from several\nregularization schemes, including actions that allow a parameterization and\ntuning of the leading cutoff effects, are presented. They lead to the\nconclusion that the Minimal Standard Model will describe physics to an accuracy\nof a few percent up to energies of the order 2 to 4 times the Higgs mass,\n$M_H$, only if $M_H \\le 710 \\pm 60 ~ GeV$. The status of Higgs and fermion mass\nbounds in Higgs-fermion models is also briefly reviewed.",
        "positive": "Computing Electromagnetic Effects in Fully Unquenched QCD: The inclusion of electromagnetic effects in unquenched QCD can be\naccomplished using ensembles generated in dynamical simulations with pure QCD\nprovided the change in the quark determinant induced by a weak electromagnetic\nfield can be efficiently computed. A stochastic technique for achieving this in\nthe case of dynamical domain wall calculations is described."
    },
    {
        "anchor": "Three-Flavor Partially Quenched Chiral Perturbation Theory at NNLO for\n  Meson Masses and Decay Constants: We discuss Partially Quenched Chiral Perturbation Theory (PQ$\\chi$PT) and\npossible fitting strategies to Lattice QCD data at next-to-next-to-leading\norder (NNLO) in the mesonic sector. We also present a complete calculation of\nthe masses of the charged pseudoscalar mesons, in the supersymmetric\nformulation of PQ$\\chi$PT. Explicit analytical results are given for up to\nthree nondegenerate sea quark flavors, along with the previously unpublished\nexpression for the pseudoscalar meson decay constant for three nondegenerate\nsea quark flavors. The numerical analysis in this paper demonstrates that the\ncorrections at NNLO are sizable, as expected from earlier work.",
        "positive": "On-shell improvement of the massive Wilson quark action: We review a relativistic approach to the heavy quark physics in lattice QCD\nby applying a relativistic $O(a)$ improvement to the massive Wilson quark\naction on the lattice. After explaining how power corrections of $m_Q a$ can be\navoided and remaining uncertainties are reduced to be of order $(a\\Lambda_{\\rm\nQCD})^2$, we demonstrate a determination of four improvement coefficients in\nthe action up to one-loop level in a mass dependent way. We also show a\nperturbative determination of mass dependent renormalization factors and $O(a)$\nimprovement coefficients for the vector and axial vector currents. Some\npreliminary results of numerical simulations are also presented."
    },
    {
        "anchor": "Extraction of the resonance parameters at finite times: In this paper we propose a model-independent method to extract the resonance\nparameters on the lattice directly from the Euclidean 2-point correlation\nfunctions of the field operators at finite times. The method is tested in case\nof the two-point function of the Delta-resonance, calculated at one loop in\nSmall Scale Expansion. Further, the method is applied to a 1+1-dimensional\nmodel with two coupled Ising spins and the results are compared with earlier\nones obtained by using Luescher's approach.",
        "positive": "Stiff self-interacting string near QCD deconfinement point: We compare the predictions of Nambu-Goto effective string model at two\nloop-order for the Casimir energy and the width of the quantum delocalization\nof the string to the corresponding quark-antiquark potential and width profile\nof the color tube in pure SU (3) Yang-Mills LGT at 4-dimensions near the\ndeconfinement point. Minor effects are returned, when considering NLO terms for\nboth the $Q\\bar{Q}$ potential and broadening of the color tube, at the\ntemperature $T/T_c= 0.8$. At a closer temperature to the critical point\n$T/T_c$= 0.9, we found that the NLO contributions, from the expansion of the\nNambu-Goto string, to have a significant effect in improving the match to\nlattice data in the intermediate distances scales. The string's\nself-interactions contribute towards the suppressed broadening of the string's\nwidth and the squeezed profile along the string at the intermediate color\nsource separation distance."
    },
    {
        "anchor": "Towards leading isospin breaking effects in mesonic masses with open\n  boundaries: We present an exploratory study of leading isospin breaking effects in\nmesonic masses using $O(a)$ improved Wilson fermions with open boundaries.\nIsospin symmetry is explicitly broken by distinct masses and electric charges\nof the up and down quarks. In order to be able to make use of existing\nisosymmetric QCD gauge ensembles we apply reweighting techniques. The path\nintegral describing QCD+QED is expanded perturbatively in powers of deviations\nin the quark masses and the inverse strong coupling as well as the\nelectromagnetic coupling. We have constructed QED$_{\\mathrm{L}}$, which we use\nas a finite volume formulation of QED, for open boundaries. We will also give a\nfirst insight into contributions from quark disconnected diagrams.",
        "positive": "Low-lying $\u039b$ Baryons with spin 1/2 in Two-flavor Lattice QCD: Low-lying $\\Lambda$ baryons with spin 1/2 are analyzed in full (unquenched)\nlattice QCD. We construct $2 \\times 2$ cross correlators from flavor SU(3)\n\"octet\" and \"singlet\" baryon operators, and diagonalize them so as to extract\ninformation of two low-lying states for each parity. The two-flavor CP-PACS\ngauge configurations are used, which are generated in the renormalization-group\nimproved gauge action and the ${\\mathcal O}(a)$-improved quark action. Three\ndifferent $\\beta$'s, $\\beta = 1.80$, 1.95 and 2.10, are employed, whose\ncorresponding lattice spacings are $a = 0.2150$, 0.1555 and 0.1076 fm. For each\ncutoff, we use four hopping parameters, ($\\kappa_{\\rm val}, \\kappa_{\\rm sea}$),\nwhich correspond to the pion masses ranging about from 500 MeV to 1.1 GeV.\nResults indicate that there are two negative-parity $\\Lambda$ states nearly\ndegenerate at around 1.6 GeV, while no state as low as $\\Lambda (1405)$ is\nobserved. By decomposing the flavor components of each state, we find that the\nlowest (1st-excited) negative-parity state is dominated by flavor-singlet\n(flavor-octet) component. We also discuss meson-baryon components of each\nstate, which has drawn considerable attention in the context of multi-quark\npictures of $\\Lambda (1405)$."
    },
    {
        "anchor": "Charmonium-like resonances with $J^{PC}=0^{++},2^{++}$ in coupled $D\\bar\n  D$, $D_s\\bar D_s$ scattering on the lattice: We present the first lattice investigation of coupled-channel $D\\bar D$ and\n$D_s\\bar D_s$ scattering in the $J^{PC}=0^{++}$ and $2^{++}$ channels. The\nscattering matrix for partial waves $l=0,2$ and isospin zero is determined\nusing multiple volumes and inertial frames via L\\\"uscher's formalism. Lattice\nQCD ensembles from the CLS consortium with $m_{\\pi}\\simeq280$ MeV, $a \\simeq\n0.09 $ fm and $L/a=24,~32$ are utilized. The resulting scattering matrix\nsuggests the existence of three charmonium-like states with $J^{PC}=0^{++}$ in\nthe energy region ranging from slightly below $2m_D$ up to 4.13 GeV. We find a\nso far unobserved $D\\bar D$ bound state just below threshold and a $D\\bar D$\nresonance likely related to $\\chi_{c0}(3860)$, which is believed to be\n$\\chi_{c0}(2P)$. In addition, there is an indication for a narrow $0^{++}$\nresonance just below the $D_s\\bar D_s$ threshold with a large coupling to\n$D_s\\bar D_s$ and a very small coupling to $D\\bar D$. This resonance is\npossibly related to the narrow $X(3915)$/$\\chi_{c0}(3930)$ observed in\nexperiment also just below $D_s\\bar D_s$. The partial wave $l=2$ features a\nresonance likely related to $\\chi_{c2}(3930)$. We work with several\nassumptions, such as the omission of $J/\\psi\\omega$, $\\eta_c\\eta$ and\nthree-particle channels. Only statistical uncertainties are quantified, while\nthe extrapolations to the physical quark-masses and the continuum limit are\nchallenges for the future.",
        "positive": "Mass spectrum and elastic scattering in the massive SU(2)_f Schwinger\n  model on the lattice: We calculate numerically scattering phases for elastic meson-meson scattering\nprocesses in the strongly coupled massive Schwinger-model with an SU(2) flavour\nsymmetry. These calculations are based on Luescher's method in which finite\nsize effects in two-particle energies are exploited. The results from\nMonte-Carlo simulations with staggered fermions for the lightest meson (\"pion\")\nare in good agreement with the analytical strong-coupling prediction.\nFurthermore, the mass spectrum of low-lying mesonic states is investigated\nnumerically. We find a surprisingly rich spectrum in the mass region [m_\\pi,4\nm_\\pi]."
    },
    {
        "anchor": "Heavy-light physics using NRQCD-staggered actions: One leading source of uncertainty in the lattice computation of semi-leptonic\nform factors in B decay, and to a lesser extent B meson decay constants, comes\nfrom the extrapolation of the light quark mass to the physical up/down mass.\nThis talk presents first explorations of simulating the light quark with\nstaggered fermion actions, which are free of the spurious zero modes that\neffect Wilson-like Dirac operators and are less costly. Methods for fitting to\nEuclidean-time NRQCD-staggered meson propagators are discussed, and some\npreliminary spectrum results are presented.",
        "positive": "Study of the scaling properties in SU(2) gauge theory with eight flavors: We present our preliminary study of the SU(2) gauge theory with 8 flavors of\nfermions in fundamental representation. This theory could be a candidate of the\ngauge theory with conformal fixed point. By using Wilson/Polyakov loop in a\nfinite volume with twisted boundary conditions, we study the renormalization\ngroup flow of the gauge coupling constant. Our calculation gives consistent\nresult with the perturbative prediction of the running coupling in the weak\ncoupling region. We investigate a possible signal for conformal behavior in the\nstrong coupling region."
    },
    {
        "anchor": "Solving relativistic three-body integral equations in the presence of\n  bound states: We present a systematically improvable method for numerically solving\nrelativistic three-body integral equations for the partial-wave projected\namplitudes. The method consists of a discretization procedure in momentum\nspace, which approximates the continuum problem with a matrix equation. It is\nsolved for different matrix sizes, and in the end, an extrapolation is employed\nto restore the continuum limit. Our technique is tested by solving a three-body\nproblem of scalar particles with an $S$ wave two-body bound state. We discuss\ntwo methods of incorporating the pole contribution in the integral equations,\nboth of them leading to agreement with previous results obtained using\nfinite-volume spectra of the same theory. We provide an analytic and numerical\nestimate of the systematic errors. Although we focus on kinematics below the\nthree-particle threshold, we provide numerical evidence that the methods\npresented allow for determination of amplitude above this threshold as well.",
        "positive": "Electromagnetic form factors of the proton and neutron from $N_f = 2 +\n  1$ lattice QCD: We present results for the electromagnetic form factors of the proton and\nneutron computed on the Coordinated Lattice Simulations (CLS) ensembles with\n$N_f = 2 + 1$ flavors of $\\mathcal{O}(a)$-improved Wilson fermions and an\n$\\mathcal{O}(a)$-improved conserved vector current. In order to estimate the\nexcited-state contamination, we employ several source-sink separations and\napply the summation method. The quark-disconnected diagrams entering the\nisoscalar quantities are computed explicitly. For this purpose, a stochastic\nestimation based on the one-end trick is performed, in combination with a\nfrequency-splitting technique and the hopping-parameter expansion. By these\nmeans, we obtain a clear signal for the form factors including the\nquark-disconnected contributions, which have a statistically significant effect\non our results. From the $Q^2$-dependence of the form factors, we determine the\nelectric and magnetic charge radii and the magnetic moments of the proton and\nneutron. The chiral interpolation is carried out by simultaneously fitting the\npion mass and $Q^2$-dependence of our form factor data directly to the\nexpressions resulting from covariant chiral perturbation theory including\nvector mesons. To assess the influence of systematic effects, we average over\nvarious cuts in the pion mass and the momentum transfer, as well as over\ndifferent models for the lattice spacing and finite volume dependence."
    },
    {
        "anchor": "JLQCD's dynamical overlap project: We present an overview of our project of large-scale simulations with\ndynamical overlap fermions. The first production run in two-flavor QCD is\non-going using the Iwasaki gauge action on a 16^3 \\times 32 lattice at the\nlattice spacing of 0.12fm with six sea quark masses down to m_{s,phys}/6, where\nm_{s,phys} is the physical strange quark mass. We briefly introduce our choice\nof the lattice action and simulation algorithm, and describe the present status\nof the production run. Preliminary results on the light meson masses and the\nstatic quark potential are also reported.",
        "positive": "Proton-proton fusion and tritium $\u03b2$-decay from lattice quantum\n  chromodynamics: The nuclear matrix element determining the $pp\\to d e^+ \\nu$ fusion cross\nsection and the Gamow-Teller matrix element contributing to tritium\n$\\beta$-decay are calculated with lattice Quantum Chromodynamics (QCD) for the\nfirst time. Using a new implementation of the background field method, these\nquantities are calculated at the SU(3)-flavor-symmetric value of the quark\nmasses, corresponding to a pion mass of $m_\\pi$ ~ 806 MeV. The Gamow-Teller\nmatrix element in tritium is found to be 0.979(03)(10) at these quark masses,\nwhich is within $2\\sigma$ of the experimental value. Assuming that the\nshort-distance correlated two-nucleon contributions to the matrix element\n(meson-exchange currents) depend only mildly on the quark masses, as seen for\nthe analogous magnetic interactions, the calculated $pp\\to d e^+ \\nu$\ntransition matrix element leads to a fusion cross section at the physical quark\nmasses that is consistent with its currently accepted value. Moreover, the\nleading two-nucleon axial counterterm of pionless effective field theory is\ndetermined to be $L_{1,A}=3.9(0.1)(1.0)(0.3)(0.9)\\ {\\rm fm}^3$ at a\nrenormalization scale set by the physical pion mass, also in agreement with the\naccepted phenomenological range. This work concretely demonstrates that weak\ntransition amplitudes in few-nucleon systems can be studied directly from the\nfundamental quark and gluon degrees of freedom and opens the way for subsequent\ninvestigations of many important quantities in nuclear physics."
    },
    {
        "anchor": "Strong coupling constant from vacuum polarization functions in\n  three-flavor lattice QCD with dynamical overlap fermions: We determine the strong coupling constant $\\alpha_s$ from a lattice\ncalculation of vacuum polarization functions (VPF) in three-flavor QCD with\ndynamical overlap fermions. Fitting lattice data of VPF to the continuum\nperturbative formula including the operator product expansion, we extract the\nQCD scale parameter $\\Lambda_{\\overline{MS}}^{(3)}$. At the $Z$ boson mass\nscale, we obtain $\\alpha_s^{(5)}(M_Z)=0.1181(3)(^{+14}_{-12})$, where the first\nerror is statistical and the second is our estimate of various systematic\nuncertainties.",
        "positive": "Infrared Divergent Coulomb Self-Energy in Yang-Mills Theory: It is shown numerically that the Coulomb self-energy of an isolated, color\nnon-singlet source diverges in an infinite volume. This is in accord with the\nGribov Horizon scenario of confinement advocated by Gribov and Zwanziger. It is\nalso shown that this divergence can be attributed to the presence of center\nvortices in thermalized lattice configurations."
    },
    {
        "anchor": "Numerical simulation of heavy fermions in an SU(2)_L x SU(2)_R symmetric\n  Yukawa model: An exploratory numerical study of the influence of heavy fermion doublets on\nthe mass of the Higgs boson is performed in the decoupling limit of a chiral\n$\\rm SU(2)_L \\otimes SU(2)_R$ symmetric Yukawa model with mirror fermions. The\nbehaviour of fermion and boson masses is investigated at infinite bare quartic\ncoupling on $4^3 \\cdot 8$, $6^3 \\cdot 12$ and $8^3 \\cdot 16$ lattices. A first\nestimate of the upper bound on the renormalized quartic coupling as a function\nof the renormalized Yukawa-coupling is given.",
        "positive": "Discretisation Errors in Landau Gauge on the Lattice: Lattice discretisation errors in the Landau gauge condition are examined. An\nimproved gauge fixing algorithm in which ${\\cal O}(a^2)$ errors are removed is\npresented. ${\\cal O}(a^2)$ improvement of the gauge fixing condition improves\ncomparison with continuum Landau gauge in two ways: 1) through the elimination\nof ${\\cal O}(a^2)$ errors and 2) through a secondary effect of reducing the\nsize of higher-order errors. These results emphasise the importance of\nimplementing an improved gauge fixing condition."
    },
    {
        "anchor": "P-Wave Two-Particle Bound and Scattering States in a Finite Volume\n  including QED: The mass shifts for two-fermion bound and scattering P-wave states subject to\nthe long-range interactions due to QED in the non-relativistic regime are\nderived. Introducing a short range force coupling the spinless fermions to one\nunit of angular momentum in the framework of pionless EFT, we first calculate\nboth perturbatively and non-perturbatively the Coulomb corrections to\nfermion-fermion scattering in the continuum and infinite volume context.\nMotivated by the research on particle-antiparticle bound states, we extend the\nresults to fermions of identical mass and opposite charge. Second, we transpose\nthe system onto a cubic lattice with periodic boundary conditions and we\ncalculate the finite volume corrections to the energy of the lowest bound and\nunbound $T_1^{\\pm}$ eigenstates. In particular, power law corrections\nproportional to the fine structure constant and resembling the recent results\nfor S-wave states are found. Higher order contributions in $\\alpha$ are\nneglected, since the gapped nature of the momentum operator in the lattice\nenvironnement allows for a perturbative treatment of the QED interactions.",
        "positive": "Cooling and the SU(2) Instanton Vaccuum: We present results of an investigation into the nature of instantons in\n4-dimensional pure gauge lattice $SU(2)$\\ obtained from configurations which\nhave been cooled using an under-relaxed cooling algorithm. We discuss ways of\ncalibrating the cooling and the effects of different degrees of cooling, and\ncompare our data for the shapes, sizes and locations of instantons with\ncontinuum results. In this paper we extend the ideas and techniques developed\nby us for use in $O(3)$, and compare the results with those obtained by other\ngroups."
    },
    {
        "anchor": "Undesirable effects of covariance matrix techniques for error analysis: Regression with $\\chi^2$ constructed from the covariance matrix should not be\nused for some combinations of covariance matrices and fitting functions. Using\nthe technique for unsuitable combinations can amplify systematic errors. This\namplification is uncontrolled, and can produce arbitrarily inaccurate results\nthat might not be ruled out by a $\\chi^2$ test. In addition, this technique can\ngive incorrect (artificially small) errors for fit parameters. I give a test\nfor this instability and a more robust (but computationally more intensive)\nmethod for fitting correlated data.",
        "positive": "Confining string and P-vortices in the indirect Z(2) projection of SU(2)\n  lattice gauge theory: We study the distribution of P-vortices near the confining string in the\nindirect Z(2) projection of SU(2) lattice gauge theory. It occurs that the\ndensity of vortices is constant at large distances and strongly suppressed near\nthe line connecting the test quark-antiquark pair. This means that the\ncondensate of P-vortices is broken inside the confining string. We also find\nthat the width of the P-vortex density distribution is proportional to the\nlogarithm of the distance between the quark and antiquark."
    },
    {
        "anchor": "Eigenvalue Distributions of the QCD Dirac Operator: We compute by Monte Carlo methods the individual distributions of the $k$th\nsmallest Dirac operator eigenvalues in QCD, and compare them with recent\nanalytical predictions. We do this for both massless and massive quarks in an\nSU(3) gauge theory with staggered fermions. Very precise agreement is found in\nall cases. As a simple by-product we also extract the microscopic spectral\ndensity of the Dirac operator in SU(3) gauge theory with dynamical massive\nfermions for $N_f=1$ and 2, and obtain high-accuracy agreement with analytical\nexpressions.",
        "positive": "Portable multi-node LQCD Monte Carlo simulations using OpenACC: This paper describes a state-of-the-art parallel Lattice QCD Monte Carlo code\nfor staggered fermions, purposely designed to be portable across different\ncomputer architectures, including GPUs and commodity CPUs. Portability is\nachieved using the OpenACC parallel programming model, used to develop a code\nthat can be compiled for several processor architectures. The paper focuses on\nparallelization on multiple computing nodes using OpenACC to manage parallelism\nwithin the node, and OpenMPI to manage parallelism among the nodes. We first\ndiscuss the available strategies to be adopted to maximize performances, we\nthen describe selected relevant details of the code, and finally measure the\nlevel of performance and scaling-performance that we are able to achieve. The\nwork focuses mainly on GPUs, which offer a significantly high level of\nperformances for this application, but also compares with results measured on\nother processors."
    },
    {
        "anchor": "Current status of $\\varepsilon_K$ in lattice QCD: We present the current status of $\\varepsilon_K$ evaluated directly from the\nstandard model using lattice QCD inputs. The lattice QCD inputs include\n$\\hat{B}_K$, $\\xi_0$, $\\xi_2$, $|V_{us}|$, $m_c(m_c)$, and $|V_{cb}|$.\nRecently, FLAG has updated $\\hat{B}_K$, exclusive $|V_{cb}|$ has been updated\nwith new lattice data in the $\\bar{B}\\to D\\ell\\bar{\\nu}$ decay mode, and\nRBC-UKQCD has updated $\\xi_0$ and $\\xi_2$. We find that the standard model\nevaluation of $\\varepsilon_K$ with exclusive $|V_{cb}|$ (lattice QCD inputs) is\n$3.2\\sigma$ lower than the experimental value, while that with inclusive\n$|V_{cb}|$ (heavy quark expansion) shows no tension.",
        "positive": "The localization transition in SU(3) gauge theory: We study the Anderson-like localization transition in the spectrum of the\nDirac operator of quenched QCD. Above the deconfining transition we determine\nthe temperature dependence of the mobility edge separating localized and\ndelocalized eigenmodes in the spectrum. We show that the temperature where the\nmobility edge vanishes and localized modes disappear from the spectrum,\ncoincides with the critical temperature of the deconfining transition. We also\nidentify topological charge related close to zero modes in the Dirac spectrum\nand show that they account for only a small fraction of localized modes, a\nfraction that is rapidly falling as the temperature increases."
    },
    {
        "anchor": "Symanzik flow on HISQ ensembles: We report on a scale determination with gradient-flow techniques on the $N_f\n= 2 + 1 + 1$ HISQ ensembles generated by the MILC collaboration. The lattice\nscale $w_0/a$, originally proposed by the BMW collaboration, is computed using\nSymanzik flow at four lattice spacings ranging from 0.15 to 0.06 fm. With a\nTaylor series ansatz, the results are simultaneously extrapolated to the\ncontinuum and interpolated to physical quark masses. We give a preliminary\ndetermination of the scale $w_0$ in physical units, along with associated\nsystematic errors, and compare with results from other groups. We also present\na first estimate of autocorrelation lengths as a function of flowtime for these\nensembles.",
        "positive": "Lattice QCD calculations of the quark and gluon contributions to the\n  proton spin: A review of the calculations of the proton's spin using lattice QCD is\npresented. Results for the three contributions, the quark contribution\n$\\sum_{q=u,d,s,c} (\\frac{1}{2} {\\Delta q})$, the total angular momentum of the\nquarks $J_q$ and of the gluons $J_g$, and the orbital angular momentum of the\nquarks are discussed. The best measured is the the quark contribution\n$\\sum_{q=u,d,s,c} (\\frac{1}{2} {\\Delta q})$, and its analysis is used to\ndiscuss the relative merits of calculations by the PNDME, ETMC and $\\chi$QCD\ncollaborations and the level of control over systematic errors achieved in\neach. The result by the PNMDE collaboration, $\\sum_{q=u,d,s} \\left[ \\frac{1}{2}\n{\\Delta q} \\right] = 0.143(31)(36) $, is consistent with the COMPASS analysis\n$0.13 < \\frac{1}{2} \\Delta \\Sigma < 0.18$. Results for $J_q$ and $J_g$ by the\nETMC collaborations are also consistent with phenomenology. Lastly, I review\nfirst results from the LHPC collaboration for the calculation of the orbital\nangular momentum of the quarks. With much larger computing resources\nanticipated over the next five years, high precision results for all three will\nbecome available and provide a detailed description of their relative\ncontributions to the nucleon spin."
    },
    {
        "anchor": "First Evidence for Center Dominance in SU(3) Lattice Gauge Theory: The dominance of center degrees of freedom is observed in SU(3) lattice gauge\ntheory in maximal center gauge. The full asymptotic string tension is\nreproduced, after center projection, by the center elements alone. When center\nvortices are removed from lattice configurations, the string tension tends to\nzero. This provides further evidence for the role played by center vortices in\nthe mechanism of color confinement in quantum chromodynamics, but more\nextensive simulations with a better gauge-fixing procedure are still needed.",
        "positive": "Lattice study for conformal windows of SU(2) and SU(3) gauge theories\n  with fundamental fermions: We present our investigation of SU(2) gauge theory with 8 flavours, and SU(3)\ngauge theory with 12 flavours. For the SU(2) case, at strong bare coupling,\n$\\beta \\lesssim 1.45$, the distribution of the lowest eigenvalue of the Dirac\noperator can be described by chiral random matrix theory for the Gaussian\nsymplectic ensemble. Our preliminary result indicates that the chiral phase\ntransition in this theory is of bulk nature. For the SU(3) theory, we use\nhigh-precision lattice data to perform the step-scaling study of the coupling,\n$g_{{\\rm GF}}$, in the Gradient Flow scheme. We carefully examine the\nreliability of the continuum extrapolation in the analysis, and conclude that\nthe scaling behaviour of this SU(3) theory is not governed by possible infrared\nconformality at $g_{{\\rm GF}}^{2} \\lesssim 6$."
    },
    {
        "anchor": "Topological susceptibility through the deconfining phase transition: We present a measurement of the topological susceptibility in SU(3)\nYang-Mills theory through the deconfinement phase transition. An improved\noperator is used for the topological charge density. A drop by an order of\nmagnitude is observed from the confined to the deconfined phase.",
        "positive": "A disorder analysis of the Ising model: Lattice studies of monopole condensation in QCD are based on the construction\nof a disorder parameter, a creation operator of monopoles which is written in\nterms of the gauge fields. This procedure is expected to work for any system\nwhich presents duality. We check it on the Ising model in 2d, which is exactly\nsolvable. The output is an amusing exercise in statistical mechanics."
    },
    {
        "anchor": "Gauge-invariant field-strength correlators for QCD in a magnetic\n  background: We consider the properties of the gauge-invariant two-point correlation\nfunctions of the gauge-field strengths for QCD in the presence of a magnetic\nbackground field. We discuss the general structure of the correlators in this\ncase and provide the results of an exploratory lattice study for $N_f = 2$ QCD\ndiscretized with unimproved staggered fermions. Our analysis provides evidence\nfor the emergence of anisotropies in the non-perturbative part of the\ncorrelators and for an increase of the gluon condensate as a function of the\nexternal magnetic field.",
        "positive": "Cosmic Strings on the Lattice: We develop a formalism for the quantization of topologically stable\nexcitations in the 4-dimensional abelian lattice gauge theory. The excitations\nare global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The\noperators of creation and annihilation of string states are constructed; the\nstring Green functions are represented as a path integral over random surfaces.\nTopological excitations play an important role in the early universe. In the\nbroken symmetry phase of the $U(1)$ spin model, closed global cosmic strings\narise, while in the Higgs phase of the noncompact gauge-Higgs model, local\ncosmic strings are present. The compact gauge-Higgs model also involves\nmonopoles. Then the strings can break if their ends are capped by monopoles.\nThe topology of the Euclidean string world sheets are studied by numerical\nsimulations."
    },
    {
        "anchor": "The nonperturbative quark-gluon vertex: We show results for the quark-gluon vertex in the Landau gauge, using a\nmean-field improved Sheikholeslami-Wohlert fermion action. We compute all the\nthree non-zero form factors of the vertex at zero gluon momentum, and compare\nthem to the abelian vertex. The quark mass dependence of the vertex is also\ninvestigated and found to be negligible for the range of masses considered.",
        "positive": "Second Moment of the Pion Light-cone Distribution Amplitude from Lattice\n  QCD: We present the results of a lattice study of the second moment of the\nlight-cone pion distribution amplitude using two flavors of dynamical (clover)\nfermions on lattices of different volumes and pion masses down to $m_\\pi\\sim\n150 \\, \\mathrm {MeV}$. At lattice spacings between $0.06 \\, \\mathrm {fm}$ and\n$0.08 \\, \\mathrm {fm}$ we find for the second Gegenbauer moment the value $a_2\n= 0.1364(154)(145)$ at the scale $\\mu=2 \\, \\mathrm {GeV}$ in the\n$\\overline{\\mathrm{MS}}$ scheme, where the first error is statistical including\nthe uncertainty of the chiral extrapolation, and the second error is the\nestimated uncertainty coming from the nonperturbatively determined\nrenormalization factors."
    },
    {
        "anchor": "Gauge invariant Field Strength Correlators in QCD: Gauge invariant correlators in QCD are studied on the lattice.A Systematic\ndetermination of the correlation lengths for gluon field strength correlators\nand quark correlators is made.The measurement of the gluon and quark\ncondensates is discussed.",
        "positive": "Confining string beyond the free approximation: the case of random\n  percolation: The random percolation model can be viewed as the dual of a well defined\nconfining gauge theory; since this theory, having no Monte Carlo dynamics at\nall, is simple to simulate, it is possible to study the properties of the flux\ntube with very high precision; we show it can be described by the effective\nstring picture. Our results are lattice regularisation independent, therefore\nthey are well defined also in the continuum limit, and, for the first time in a\ngauge theory, it has been possible to determine the next-to-leading quantum\ncorrections throughout the computation of the T^6 coefficient of the Taylor\nexpansion of sigma(T). Furthermore, this coefficient results to be related to\nthe universal ratio T_c/\\sqrt{sigma_0}."
    },
    {
        "anchor": "Critical Slowing-Down in SU(2) Landau-Gauge-Fixing Algorithms at beta =\n  infinity: We evaluate numerically and analytically the dynamic critical exponent $z$\nfor five gauge-fixing algorithms in SU(2) lattice Landau-gauge theory by\nconsidering the case $\\beta = \\infty$. Numerical data are obtained in two,\nthree and four dimensions. Results are in agreement with those obtained\npreviously at finite $\\beta$ in two dimensions. The theoretical analysis, valid\nfor any dimension $d$, helps us clarify the tuning of these algorithms. We also\nstudy generalizations of the overrelaxation algorithm and of the stochastic\noverrelaxation algorithm and verify that we cannot have a dynamic critical\nexponent $z$ smaller than 1 with these local algorithms. Finally, the analytic\napproach is applied to the so-called $\\lambda$-gauges, again at $\\beta =\n\\infty$, and verified numerically for the two-dimensional case.",
        "positive": "Infrared exponents and the strong-coupling limit in lattice Landau gauge: We study the gluon and ghost propagators of lattice Landau gauge in the\nstrong-coupling limit beta=0 in pure SU(2) lattice gauge theory to find\nevidence of the conformal infrared behavior of these propagators as predicted\nby a variety of functional continuum methods for asymptotically small momenta\n$q^2 \\ll \\Lambda_\\mathrm{QCD}^2$. In the strong-coupling limit, this same\nbehavior is obtained for the larger values of a^2q^2 (in units of the lattice\nspacing a), where it is otherwise swamped by the gauge field dynamics.\nDeviations for a^2q^2 < 1 are well parameterized by a transverse gluon mass\n$\\propto 1/a$. Perhaps unexpectedly, these deviations are thus no finite-volume\neffect but persist in the infinite-volume limit. They furthermore depend on the\ndefinition of gauge fields on the lattice, while the asymptotic conformal\nbehavior does not. We also comment on a misinterpretation of our results by\nCucchieri and Mendes in Phys. Rev. D81 (2010) 016005."
    },
    {
        "anchor": "Complex Langevin: Boundary terms at poles of the drift: The complex Langevin method is a general method to treat systems with complex\naction, such as QCD at nonzero density. The formal justification relies on the\nabsence of certain boundary terms, both at infinity and at the unavoidable\npoles of the drift force. Here I focus on the boundary terms at these poles for\nsimple models, which so far have not been discussed in detail. The main result\nis that those boundary terms (for the \"un-evolved\" observables) arise after\nrunning the Langevin process for a finite time and vanish again as the Langevin\ntime goes to infinity. This is in contrast to the boundary terms at infinity,\nwhich can be found to occur in the long time limit (cf. the contribution by\nD\\'enes Sexty).",
        "positive": "Comment on ``Evidence Against Instanton Dominance of Topological Charge\n  Fluctuations in QCD'': We comment on the recent paper (hep-lat/0102003) by Horvath, Isgur, McCune,\nand Thacker, which concludes that the local chiral structure of fermionic\neigenmodes is not consistent with instanton dominance. Our calculations, done\nwith an overlap action, suggest the opposite conclusion."
    },
    {
        "anchor": "Meson Decay Constants from the Valence Approximation to Lattice QCD: We evaluate $f_{\\pi}/ m_{\\rho}$, $f_K/ m_{\\rho}$, $1/f_{\\rho}$, and $\nm_{\\phi}/(f_{\\phi} m_{\\rho})$, extrapolated to physical quark mass, zero\nlattice spacing and infinite volume, for lattice QCD with Wilson quarks in the\nvalence (quenched) approximation. The predicted ratios differ from experiment\nby amounts ranging from 12\\% to 17\\% equivalent to between 0.9 and 2.8 times\nthe corresponding statistical uncertainties.",
        "positive": "Scalar mass corrections from compact extra dimensions on the lattice: We explore the phase diagram of the SU(2) Yang-Mills theory in 5 dimensions\nby numerical simulations. The lattice system shows a dimensionally-reduced\nphase where the extra dimension is small compared to the four dimensional\ncorrelation length. In the low-energy regime of this phase, the system behaves\nlike a four-dimensional gauge theory coupled to an adjoint scalar field. By\ntuning the bare parameters of the lattice model, we identify lines of constant\nphysics, and analyse the behaviour of the non-perturbative scalar mass as a\nfunction of the compactification and the cut-off scales. The perturbative\nprediction that the effective theory contains a light particle with a mass that\nis independent of the cut-off is tested against non-pertubative results."
    },
    {
        "anchor": "The PZ method for estimating determinant ratios, with applications: We introduce a new method for estimating determinants or determinant ratios\nof large matrices, which combines the techniques of Pad\\`{e} approximation with\nrational functions and $Z_{2}$ noise estimation of traces of large matrices.\nThe method requires simultaneously solving several matrix equations, which can\nbe conveniently accomplished using the MR method. We include some preliinary\nresults, and indicate potential applications to non-Hermitian matrices, and\nHybrid Monte Carlo without pseudofermions.",
        "positive": "Exploring a hidden symmetry with electrically charged quarks: It is usual to study confinement via quantum chromodynamics (QCD) alone. The\ndeconfinement transition of the pure gauge theory (i.e. with static quarks) is\nthen characterized by the breaking of center symmetry. Center vortices offer an\nintuitive and quantitative description of the transition. Dynamical quarks\nexplicitly break center symmetry, and the phase transition becomes a crossover.\nHowever, it may be misleading to study QCD in isolation. Quarks also carry\nfractional electric charge. This bestows the Standard Model with a global\ncenter symmetry that combines color center phases with an appropriate\nelectromagnetic phase. Is this symmetry relevant to confinement? We begin our\ninvestigation by studying a 2-color model of QCD with half-integer electrically\ncharged quarks."
    },
    {
        "anchor": "Intermittency Studies in Directed Bond Percolation: The self-similar cluster fluctuations of directed bond percolation at the\npercolation threshold are studied using techniques borrowed from\ninter\\-mit\\-ten\\-cy-related analysis in multi-particle production. Numerical\nsimulations based on the factorial moments for large $1+1$-dimensional lattices\nallow to handle statistical and boundary effects and show the existence of weak\nbut definite intermittency patterns. The extracted fractal dimensions are in\nagreement with scaling arguments leading to a new relation linking the\nintermittency indices to the critical exponents and the fractal dimension of\ndirected percolation clusters.",
        "positive": "Phases of SU(3) Gauge Theories with Fundamental Quarks via Dirac\n  Spectral Density: We propose that, in SU(3) gauge theories with fundamental quarks, confinement\ncan be inferred from spectral density of the Dirac operator. This stems from\nthe proposition that its possible behaviors are exhausted by three distinct\ntypes (Fig.1). The monotonic cases are standard and entail confinement with\nvalence chiral symmetry breaking (A) or the lack of both (C,C'). The bimodal\n(anomalous) option (B) was frequently regarded as an artifact (lattice or\nother) in previous studies, but we show for the first time that it persists in\nthe continuum limit, and conclude that it informs of a non-confining phase with\nbroken valence chiral symmetry. This generalization rests on the following.\n$(\\alpha)$ We show that bimodality in $N_f$=0 theory past deconfinement\ntemperature $T_c$ is stable with respect to removal of both infrared and\nultraviolet cutoffs, indicating that anomalous phase is not an artifact.\n$(\\beta)$ We demonstrate that transition to bimodality in $N_f$=0 is\nsimultaneous with the loss of confinement: anomalous phase occurs for $T_c < T\n< T_{ch}$, where $T_{ch}$ is the valence chiral restoration temperature.\n$(\\gamma)$ Evidence is presented for thermal anomalous phase in $N_f$=2+1 QCD\nat physical quark masses, whose onset too coincides with the conventional\n\"crossover $T_c$''. We conclude that the anomalous regime $T_c < T < T_{ch}$ is\nvery likely a feature of nature's strong interactions. $(\\delta)$ Our past\nstudies of zero-temperature $N_f$=12 theories revealed that bimodality also\narises via purely light-quark effects. As a result, we expect to encounter\nanomalous phase on generic paths to valence chiral restoration. We predict its\nexistence also for $N_f$ massless flavors ($T=0$) in the range $N_f^c < N_f <\nN_f^{ch}$, where $N_f^c$ could be quite low. Conventional arguments would\nassociate $N_f^{ch}$ with the onset of conformal window."
    },
    {
        "anchor": "A novel method for evaluating correlation functions in lattice hadron\n  spectroscopy: We describe a new approach for evaluating hadronic correlation functions\nwhich combines Laplacian-Heaviside quark smearing with a stochastic estimator\nof quark propagators. This method utilizes noise dilution in a new way to\nreduce the variance in correlators. The efficacy of the new algorithm is\ndemonstrated on a number of systems, including disconnected diagrams and\nmulti-hadron correlators, on a small lattice where comparisons with the results\nobtained with exactly determined quark propagators are possible. On larger\nlattice volumes, the use of exact propagators becomes prohibitively expensive,\nwhile the stochastic method is still computationally feasible.",
        "positive": "A first look at quasi-Monte Carlo for lattice field theory problems: In this project we initiate an investigation of the applicability of\nQuasi-Monte Carlo methods to lattice field theories in order to improve the\nasymptotic error behavior of observables for such theories. In most cases the\nerror of an observable calculated by averaging over random observations\ngenerated from an ordinary Monte Carlo simulation behaves like 1/sqrt(N), where\nN is the number of observations. By means of Quasi-Monte Carlo methods it is\npossible to improve this behavior for certain problems to up to 1/N. We adapted\nand applied this approach to simple systems like the quantum harmonic and\nanharmonic oscillator and verified an improved error scaling."
    },
    {
        "anchor": "Coulomb Energy, Remnant Symmetry, and the Phases of Non-Abelian Gauge\n  Theories: We show that the confining property of the one-gluon propagator, in Coulomb\ngauge, is linked to the unbroken realization of a remnant gauge symmetry which\nexists in this gauge. An order parameter for the remnant gauge symmetry is\nintroduced, and its behavior is investigated in a variety of models via\nnumerical simulations. We find that the color-Coulomb potential, associated\nwith the gluon propagator, grows linearly with distance both in the confined\nand - surprisingly - in the high-temperature deconfined phase of pure\nYang-Mills theory. We also find a remnant symmetry-breaking transition in SU(2)\ngauge-Higgs theory which completely isolates the Higgs from the\n(pseudo)confinement region of the phase diagram. This transition exists despite\nthe absence, pointed out long ago by Fradkin and Shenker, of a genuine\nthermodynamic phase transition separating the two regions.",
        "positive": "Reconciling the lattice background field method with nonrelativistic\n  QED: Spinor case: We show that inconsistency between background field methods, which are\nrelevant for lattice QCD spectroscopy, and effective field theory matching\nconditions, which are obtained from scattering amplitudes, can be resolved by\naugmenting nonrelativistic QED with operators related by the equations of\nmotion. To determine the coefficients of such operators, we perform the\nnonrelativistic expansion of QED for a spin-half hadron including non-minimal\nelectromagnetic couplings. As an effective field theory framework could provide\na valuable tool to analyze lattice QCD correlation functions in external\nfields, we investigate whether nonrelativistic QED can be used to this end. We\nargue, however, that the most desirable approach is a hybrid one, which\ncombines a relativistic hadron theory with operator selection based on\nnonrelativistic QED power counting. In this hybrid framework, new results are\nobtained for charged spin-half hadrons in uniform magnetic fields, including a\nproper treatment of Landau levels both in infinite volume and on a torus."
    },
    {
        "anchor": "O(N) universality and the chiral phase transition in QCD: We discuss universal scaling properties of (2+1)-flavor QCD in the vicinity\nof the chiral phase transition at vanishing as well as non-vanishing light\nquark chemical potential (mu_l). We provide evidence for O(N) scaling of the\nchiral order parameter in (2+1)-flavor QCD and show that the scaling analysis\nof its derivative with respect to the light quark chemical potential provides a\nunique approach to the determination of the curvature of the chiral phase\ntransition line in the vicinity of mu_l/T=0.",
        "positive": "Optimized meson operators for charmonium spectroscopy and mixing with\n  glueballs: Optimized meson operators in the distillation framework are used to study the\ncharmonium spectrum in two ensembles with two heavy dynamical quarks at half\nthe physical charm quark mass but different lattice spacings. The use of\noptimal meson distillation profiles is shown to increase the overlap with the\nground state significantly, as well as grant access to excited states, for\nmultiple quantum numbers including hybrid states with very little additional\ncost. These same operators are also employed for the calculation of\nmeson-glueball mixing."
    },
    {
        "anchor": "Pion and kaon form factors using twisted-mass fermions: We present a calculation of the scalar, vector and tensor pion and kaon form\nfactors using one ensemble of two degenerate light, a strange and a charm quark\n($N_f=2+1+1$) of maximally twisted mass fermions with clover improvement. The\nquark masses are chosen so that they produce a pion mass of about 265 MeV, and\na kaon mass of 530 MeV. The lattice spacing of the ensemble is 0.093 fm and the\nlattice has a spatial extent of 3 fm. We use a rest frame, as well as a boosted\nframe to obtain the form factors for a wider and denser set of four-vector\nmomentum transfer squared, $Q^2$. To assess and eliminate excited-states\ncontamination, we analyze several values of the source-sink time separation\nwithin the range of 1.12 - 2.23 fm (1.12 - 1.67 fm) for the rest (boosted)\nframe. The $Q^2$ dependence of the form factors is parametrized using a\nmonopole fit, which leads to the extraction of the corresponding radius, and\nthe tensor anomalous magnetic moment for the tensor form factor. The results\nfor these parametrizations are compared for the pion and kaon to assess the\nlevel of the SU(3) flavor symmetry breaking.",
        "positive": "Mixed action computations on fine dynamical lattices: We report on our first experiences in simulating Neuberger valence fermions\non CLS $N_f=2$ configurations with light sea quark masses and small lattice\nspacings. Valence quark masses are considered that allow to explore the\nmatching to (partially quenched) chiral perturbation theory both in the\n$\\epsilon$- and $p$-regimes. The setup is discussed, and first results are\npresented for spectral observables."
    },
    {
        "anchor": "Statistical analysis method for the worldvolume hybrid Monte Carlo\n  algorithm: We discuss the statistical analysis method for the worldvolume hybrid Monte\nCarlo (WV-HMC) algorithm [arXiv:2012.08468], which was recently introduced to\nsubstantially reduce the computational cost of the tempered Lefschetz thimble\nmethod. In the WV-HMC algorithm, the configuration space is a continuous\naccumulation (worldvolume) of deformed integration surfaces, and sample\naverages are considered for various subregions in the worldvolume. We prove\nthat, if a sample in the worldvolume is generated as a Markov chain, then the\nsubsample in the subregion can also be regarded as a Markov chain. This ensures\nthe application of the standard statistical techniques to the WV-HMC algorithm.\nWe particularly investigate the autocorrelation times for the Markov chains in\nvarious subregions, and find that there is a linear relation between the\nprobability to be in a subregion and the autocorrelation time for the\ncorresponding subsample. We numerically confirm this scaling law for a chiral\nrandom matrix model.",
        "positive": "One loop calculation of the renormalised anisotropy for improved\n  anisotropic gluon actions on a lattice: Using the infrared dispersion relation of the on shell gluon, we calculate\nthe renormalisation of the the anisotropy to one loop in perturbation theory\nfor lattice Yang-Mills theories, including the Wilson action and actions with\nSymanzik and/or tadpole improvement. Using twisted boundary conditions as a\ngauge invariant infrared regulator, we show for an SU(3) gauge group in D=3+1\ndimensions that the one loop anisotropy is accurate to O(3%) for a range of g^2\nand chi covering current simulations. In doing so we also present Feynman rules\nfor SU(N) gauge groups with generic anisotropy structure (including `3+1' and\n`2+2' cases)."
    },
    {
        "anchor": "Meson screening masses at finite temperature with Highly Improved\n  Staggered Quarks: We report on the first study of the screening properties of the mesonic\nexcitations with strange ($s$) and charm ($c$) quarks, specifically the ground\nstates of the pseudo-scalar and vector meson excitations for the $\\bar{s}s$,\n$\\bar{s}c$ and $\\bar{c}c$ flavor combinations, using the Highly Improved\nStaggered Quark action with dynamical physical strange quark and\nnearly-physical up and down quarks. By comparing with their respective vacuum\nmeson masses and by investigating the influence of the changing temporal\nboundary conditions of the valence quarks we study the thermal modifications of\nthese mesonic excitations. While the $\\bar{s}s$ states show significant\nmodifications even below the chiral crossover temperature $T_c$, the\nmodifications of the open-charm and charmonium like states become visible only\nfor temperatures $T\\gtrsim T_c$ and $T\\gtrsim1.2T_c$, respectively.",
        "positive": "Isospin-1/2 $D\u03c0$ scattering and the lightest $D_0^\\ast$ resonance from\n  lattice QCD: Isospin-1/2 $D\\pi$ scattering amplitudes are computed using lattice QCD,\nworking in a single volume of approximately $(3.6\\; \\mathrm{fm})^3$ and with a\nlight quark mass corresponding to $m_\\pi\\approx239$ MeV. The spectrum of the\nelastic $D\\pi$ energy region is computed yielding 20 energy levels. Using the\nL\\\"uscher finite-volume quantisation condition, these energies are translated\ninto constraints on the infinite-volume scattering amplitudes and hence enable\nus to map out the energy dependence of elastic $D\\pi$ scattering. By\nanalytically continuing a range of scattering amplitudes, a $D_0^\\ast$\nresonance pole is consistently found strongly coupled to the $S$-wave $D\\pi$\nchannel, with a mass $m\\approx 2200$ MeV and a width $\\Gamma\\approx400$ MeV.\nCombined with earlier work investigating the $D_{s0}^\\ast$, and $D_0^\\ast$ with\nheavier light quarks, similar couplings between each of these scalar states and\ntheir relevant meson-meson scattering channels are determined. The mass of the\n$D_0^\\ast$ is consistently found well below that of the $D_{s0}^\\ast$, in\ncontrast to the currently reported experimental result."
    },
    {
        "anchor": "Chiral Fermions from Lattice Boundaries: We construct a model in which four dimensional chiral fermions arise on the\nboundaries of a five dimensional lattice with free boundary conditions in the\nfifth direction. The physical content is similar to Kaplan's model of domain\nwall fermions, yet the present construction has several technical advantages.\nWe discuss some aspects of perturbation theory, as well as possible\napplications of the model both for lattice QCD and for the on-going attempts to\nconstruct a lattice chiral gauge theory.",
        "positive": "Hamiltonian lattice quantum chromodynamics at finite density with Wilson\n  fermions: Quantum chromodynamics (QCD) at sufficiently high density is expected to\nundergo a chiral phase transition. Understanding such a transition is of\nparticular importance for neutron star or quark star physics. In Lagrangian\nSU(3) lattice gauge theory, the standard approach breaks down at large chemical\npotential $\\mu$, due to the complex action problem. The Hamiltonian formulation\nof lattice QCD doesn't encounter such a problem. In a previous work, we\ndeveloped a Hamiltonian approach at finite chemical potential $\\mu$ and\nobtained reasonable results in the strong coupling regime. In this paper, we\nextend the previous work to Wilson fermions. We study the chiral behavior and\ncalculate the vacuum energy, chiral condensate and quark number density, as\nwell as the masses of light hadrons. There is a first order chiral phase\ntransition at zero temperature."
    },
    {
        "anchor": "Determination of quark masses from $\\mathbf{n_f=4}$ lattice QCD and the\n  RI-SMOM intermediate scheme: We determine the charm and strange quark masses in the $\\overline{\\text{MS}}$\nscheme, using $n_f=2+1+1$ lattice QCD calculations with highly improved\nstaggered quarks (HISQ) and the RI-SMOM intermediate scheme to connect the bare\nlattice quark masses to continuum renormalisation schemes. Our study covers\nanalysis of systematic uncertainties from this method, including\nnonperturbative artefacts and the impact of the non-zero physical sea quark\nmasses. We find $m_c^{\\overline{\\text{MS}}}(3 \\text{GeV}) = 0.9896(61)$ GeV and\n$m_s^{\\overline{\\text{MS}}}(3 \\text{GeV}) = 0.08536(85)$ GeV, where the\nuncertainties are dominated by the tuning of the bare lattice quark masses.\nThese results are consistent with, and of similar accuracy to, those using the\ncurrent-current correlator approach coupled to high-order continuum QCD\nperturbation theory, implemented in the same quark formalism and on the same\ngauge field configurations. This provides a strong test of the consistency of\nmethods for determining the quark masses to high precision from lattice QCD. We\nalso give updated lattice QCD world averages for $c$ and $s$ quark masses.",
        "positive": "Fermion mass generation without a condensate: We study a lattice field theory model containing two flavors of massless\nstaggered fermions with an onsite four-fermion interaction. The symmetry of the\nmodel forbids non-zero fermion bilinear order parameters that can generate a\nfermion mass. At weak couplings, we expect a massless fermion phase. At strong\ncouplings, we can argue for the existence of massive fermions without the\nformation of any fermion bilinear condensate. Using Monte Carlo calculations in\nthree space-time dimensions, we find evidence for a direct second order phase\ntransition between the two phases."
    },
    {
        "anchor": "$\u03a9\u03a9$ interaction from 2+1 flavor lattice QCD: We investigate the interaction between $\\Omega$ baryons in the $^1S_0$\nchannel from 2+1 flavor lattice QCD simulations. On the basis of the HAL QCD\nmethod, the $\\Omega\\Omega$ potential is extracted from the Nambu-Bethe-Salpeter\nwave function calculated on the lattice by using the PACS-CS gauge\nconfigurations with the lattice spacing $a\\simeq 0.09$ fm, the lattice volume\n$L\\simeq 2.9$ fm and the quark masses corresponding to $m_\\pi \\simeq 700$ MeV\nand $m_\\Omega \\simeq 1970$ MeV. The $\\Omega\\Omega$ potential has a repulsive\ncore at short distance and an attractive well at intermediate distance.\nAccordingly, the phase shift obtained from the potential shows moderate\nattraction at low energies. Our data indicate that the $\\Omega\\Omega$ system\nwith the present quark masses may appear close to the unitary limit where the\nscattering length diverges.",
        "positive": "Efficient computation of low-lying eigenmodes of non-Hermitian\n  Wilson-Dirac type matrices: A polynomial transformation for non-Hermitian matrices is presented, which\nprovides access to wedge-shaped spectral windows. For Wilson-Dirac type\nmatrices this procedure not only allows the determination of the physically\ninteresting low-lying eigenmodes but also provides a substantial acceleration\nof the eigenmode algorithm employed."
    },
    {
        "anchor": "Analysis of Hadron Propagators with One Thousand Configurations on a\n  $24^3\\times 64$ Lattice at $\u03b2=6.0$: Statistical properties of effective mass are analyzed. We show from a general\nground that effective mass as a function of time should not exhibit long\nplateaux whatever high statistics simulations are made: the mass should\nfluctuate beyond the one standard deviation of error bars after a few time\nslices for large times where the ground state dominates. This explains the\ndifficulty of obtaining long plateaux experienced in previous simulations.\nImplications of the observation for global $\\chi^2$ fits are discussed, and\nresults for hadron masses are presented.",
        "positive": "Charm quark system on the physical point in 2+1 flavor lattice QCD: We investigate the charm quark system on 2+1 flavor PACS-CS configurations.\nCalculations are performed at the lattice spacing $a^{-1}=2.194(10)$ GeV and\nthe spatial extent $L=2.9$ fm with O(a)-improved Wilson fermions for the light\nquarks and the relativistic heavy fermion for the charm quark. Our dynamical\n$ud$ and strange quark masses and valence charm quark mass are set to their\nphysical values. A comparison of the mass spectrum and decay constants with\nexperiments is presented. Our results for the charm quark mass and CKM matrix\nelements are also reported."
    },
    {
        "anchor": "$U(N)$ gauge theory in the strong coupling limit on a quantum annealer: Lattice QCD in the strong coupling regime can be formulated in dual variables\nwhich are integer-valued. It can be efficiently simulated for modest finite\ntemperatures and finite densities via the worm algorithm, circumventing the\nfinite density sign problem in this regime. However, the low temperature regime\nis more expensive to address. As the partition function is solely expressed in\nterms of integers, it can be cast as a combinatorial optimization problem that\ncan be solved on a quantum annealer. We will first explain the setup of the\nsystem we want to study, and then present its reformulation suitable for a\nquantum annealer, and in particular the D-Wave. As a proof of concept, we\npresent first results obtained on D-Wave for gauge group $U(1)$ and $U(3)$, and\noutline the next steps towards gauge groups $SU(3)$. We find that in addition,\nhistogram reweighting greatly improves the accuracy of our observables when\ncompared to analytic results.",
        "positive": "Lattice Calculation of Hadronic Light-by-Light Contribution to the Muon\n  Anomalous Magnetic Moment: The quark-connected part of the hadronic light-by-light scattering\ncontribution to the muon's anomalous magnetic moment is computed using lattice\nQCD with chiral fermions. We report several significant algorithmic\nimprovements and demonstrate their effectiveness through specific calculations\nwhich show a reduction in statistical errors by more than an order of\nmagnitude. The most realistic of these calculations is performed with a\nnear-physical, $171$ MeV pion mass on a $(4.6\\;\\mathrm{fm})^3$ spatial volume\nusing the $32^3\\times 64$ Iwasaki+DSDR gauge ensemble of the RBC/UKQCD\nCollaboration."
    },
    {
        "anchor": "Ising low-temperature polynomials and hard-sphere gases on cubic\n  lattices of general dimension: We derive and analyze the low-activity and low-density expansions of the\npressure for the model of a hard-sphere gas on cubic lattices of general\ndimension $d$, through the 13th order. These calculations are based on our\nrecent extension to dimension d of the low-temperature expansions for the\nspecific free-energy of the spin-1/2 Ising models subject to a uniform magnetic\nfield on the (hyper-)simple-cubic lattices. Estimates of the model parameters\nare given also for some other lattices",
        "positive": "Dgsos on DTRS: We perform simulations of a discrete gaussian solid on solid (DGSOS) model on\ndynamical $\\phi^3$ graphs, which is equivalent to coupling the model to 2d\nquantum gravity, using the cluster algorithms recently developed by Evertz\net.al.for use on fixed lattices. We find evidence from the growth of the\nwidth-squared in the rough phase of KT-like behaviour, which is consistent with\ntheoretical expectations. We also investigate the cluster statistics, dynamical\ncritical exponent and lattice properties, and compare these with the dual XY\nmodel."
    },
    {
        "anchor": "Auxiliary field Monte-Carlo study of the QCD phase diagram at strong\n  coupling: We investigate the QCD phase diagram in the strong coupling limit by using a\nnewly developed auxiliary field Monte-Carlo (AFMC) method. Starting from an\neffective action in the leading order of the 1/g^2 and 1/d expansion with one\nspecies of unrooted staggered fermion, we solve the many-body problem exactly\nby introducing the auxiliary fields and integrating out the temporal links and\nquark fields. We have a sign problem in AFMC, which is different from the\noriginal one in finite density lattice QCD. For low momentum auxiliary field\nmodes, a complex phase cancellation mechanism exists, and the sign problem is\nnot serious on a small lattice. Compared with the mean field results, the\ntransition temperature is found to be reduced by around 10 % and the hadron\nphase is found to be extended in the larger chemical potential direction by\naround 20 %, as observed in the monomer-dimer-polymer (MDP) simulations.",
        "positive": "Preweighting method in Monte-Carlo sampling with complex action ---\n  Strong-Coupling Lattice QCD with $1/g^2$ corrections, as an example ---: We investigate the QCD phase diagram in the strong-coupling lattice QCD with\nfluctuation and $1/g^2$ effects by using the auxiliary field Monte-Carlo\nsimulations. The complex phase of the Fermion determinant at finite chemical\npotential is found to be suppressed by introducing a complex shift of integral\npath for one of the auxiliary fields, which corresponds to introducing a\nrepulsive vector mean field for quarks. The obtained phase diagram in the\nchiral limit shows suppressed $T_c$ in the second order phase transition region\ncompared with the strong-coupling limit results. We also argue that we can\napproximately guess the statistical weight cancellation from the complex phase\nin advance in the case where the complex phase distribution is Gaussian. We\ndemonstrate that correct expectation values are obtained by using this guess in\nthe importance sampling (preweighting)."
    },
    {
        "anchor": "Large statistics study of the topological charge distribution in the\n  SU(3) gauge theory: We present preliminary results for a high statistics study of the topological\ncharge distribution in the SU(3) Yang-Mills theory obtained by using the\ndefinition of the charge suggested by Neuberger fermions. We find statistical\nevidence for deviations from a gaussian distribution. The large statistics\nrequired has been obtained by using PCs of the INFN-GRID.",
        "positive": "Stout Smearing on a Quantum Computer: Smearing of gauge-field configurations in lattice field theory improves the\nresults of lattice simulations by suppressing high energy modes from\ncorrelation functions. In quantum simulations, high kinetic energy eigenstates\nare introduced when the time evolution operator is approximated such as\nTrotterization. While improved Trotter product formulae exist to reduce the\nerrors, they have diminishing accuracy returns with respect to resource costs.\nTherefore having an algorithm that has fewer resources than an improved Trotter\nformula is desirable. In this work I develop a representation agnostic method\nfor quantum smearing and show that it reduces the coupling to high energy modes\nin the discrete nonabelian gauge theory $D_4$"
    },
    {
        "anchor": "Accessing proton GPDs in asymmetric frames: Numerical implementation: In this work, we present a numerical investigation of a novel\nLorentz-covariant parametrization to extract $x$-dependent GPDs using\noff-forward matrix elements of momentum-boosted hadrons coupled to non-local\noperators. The novelty of the method is the implementation of an asymmetric\nframe for the momentum transfer between the initial and final hadron state and\nthe parametrization of the matrix elements into Lorentz-invariant amplitudes.\nThe amplitudes can then be related to the standard light-cone GPDs.\n  GPDs are defined in the symmetric frame, which requires a separate\ncalculation for each value of the momentum transfer, increasing the\ncomputational cost significantly. The proposed method is powerful, as one can\nextract the GPDs at multiple values of the momentum transfer at the\ncomputational cost of a single value. For this proof-of-concept calculation, we\nuse one ensemble of $N_f=2+1+1$ twisted mass fermions and a clover improvement\nwith a pion mass of 260 MeV to calculate the proton unpolarized GPDs.",
        "positive": "Vacuum energy of two-dimensional N=(2,2) super Yang-Mills theory: We measure the vacuum energy of two-dimensional N=(2,2) super Yang-Mills\ntheory using lattice simulation. The obtained vacuum energy density is\nE_0=0.09(9)(+10-8) g^2, where the first error is the systematic and the second\nis the statistical one, measured in the dimensionful gauge coupling g which\ngoverns the scale of the system. The result is consistent with unbroken\nsupersymmetry, although we cannot exclude a possible very small non-zero vacuum\nenergy."
    },
    {
        "anchor": "Strangeness and charm content of the nucleon: We present results on the scalar strangeness and charm contents of the\nnucleon and of the disconnected contributions to the nucleon spin. These are\nobtained on two flavour non-perturbatively improved Sheikholeslami-Wilson\nconfigurations at a pseudoscalar mass of 290 MeV. We quote f_{T_s} =\nm_s<N|ss|N>/m_N< = 0.070(22) as our preliminary value for the strange quark\nfraction of the nucleon mass and a modified minimal subtraction scheme value\nDelta s = -0.015(10), with as yet unknown systematics, for the strangeness\ncontribution to the spin.",
        "positive": "End states, ladder compounds, and domain wall fermions: A magnetic field applied to a cross linked ladder compound can generate\nisolated electronic states bound to the ends of the chain. After exploring the\ninterference phenomena responsible, I discuss a connection to the domain wall\napproach to chiral fermions in lattice gauge theory. The robust nature of the\nstates under small variations of the bond strengths is tied to chiral symmetry\nand the multiplicative renormalization of fermion masses."
    },
    {
        "anchor": "Neutral B-meson mixing from unquenched lattice QCD with domain-wall\n  light quarks and static b-quarks: We demonstrate a method for calculating the neutral B-meson decay constants\nand mixing matrix elements in unquenched lattice QCD with domain-wall light\nquarks and static b-quarks. Our computation is performed on the \"2+1\" flavor\ngauge configurations generated by the RBC and UKQCD Collaborations with a\nlattice spacing of a approx 0.11 fm (a^-1 = 1.729 GeV) and a lattice spatial\nvolume of approximately (1.8 fm)^3. We simulate at three different light sea\nquark masses with pion masses down to approximately 430 MeV, and extrapolate to\nthe physical quark masses using a phenomenologically-motivated fit function\nbased on next-to-leading order heavy-light meson SU(2) chiral perturbation\ntheory. For the b-quarks, we use an improved formulation of the Eichten-Hill\naction with static link-smearing to increase the signal-to-noise ratio. We also\nimprove the heavy-light axial current used to compute the B-meson decay\nconstant to O(alpha_s p a) using one-loop lattice perturbation theory. We\npresent initial results for the SU(3)-breaking ratios f_{B_s}/f_{B_d} and xi =\nf_{B_s} sqrt{B_{B_s}}/f_{B_d} sqrt{B_{B_d}}, thereby demonstrating the\nviability of the method. For the ratio of decay constants, we find\nf_{B_s}/f_{B_d} = 1.15(12) and for the ratio of mixing matrix elements, we find\nxi = 1.13(12), where in both cases the errors reflect the combined statistical\nand systematic uncertainties, including an estimate of the size of neglected\nO(1/m_b) effects.",
        "positive": "Towards precision charm physics with a mixed action: We report on our first set of results for charm physics, using a mixed-action\nsetup with maximally twisted valence fermions on CLS $N_f=2+1$ ensembles. This\nsetup avoids the need of improvement coefficients to subtract $O(am_c)$\neffects. The charm quark mass, $D$ and $D_s$ decay constants are computed on a\nsubset of CLS ensembles, which allows to take the continuum limit and\nextrapolate to the physical pion mass, and assess the scaling properties.\nSpecial attention is paid to the implementation of techniques to deal with\nsystematic uncertainties. Our results show excellent prospects for\nhigh-precision computations on the full set of ensembles."
    },
    {
        "anchor": "The SU(3) running coupling from lattice gluons: We provide numerical results for the running coupling in $SU(3)$ Yang-Mills\ntheory as determined from an analysis of lattice two and three-point gluon\ncorrelation functions. The coupling is evaluated directly, from first\nprinciples, by defining suitable renormalisation constants from the lattice\ntriple gluon vertex and gluon propagator. For momenta larger than 2 GeV, the\ncoupling is found to run according to the 2-loop asymptotic formula. The\ninfluence of lattice artifacts on the results appears negligible within the\nprecision of our measurements, although further work on this point is in\nprogress.",
        "positive": "Scale setting and the light baryon spectrum in $N_f=2+1$ QCD with Wilson\n  fermions: We determine the light baryon spectrum on ensembles generated by the\nCoordinated Lattice Simulations (CLS) effort, employing $N_f=2+1$ flavours of\nnon-perturbatively improved Wilson fermions. The hadron masses are interpolated\nand extrapolated within the quark mass plane, utilizing three distinct\ntrajectories, two of which intersect close to the physical quark mass point and\nthe third one approaching the SU(3) chiral limit. The results are extrapolated\nto the continuum limit, utilizing six different lattice spacings ranging from\n$a\\approx 0.10\\,$fm down to below $0.04\\,$fm. The light pion mass varies from\n$M_{\\pi}\\approx 429\\,$MeV down to $127\\,$MeV. In general, the spatial extent is\nkept larger than four times the inverse pion mass and larger than $2.3\\,$fm,\nwith additional small and large volume ensembles to investigate finite size\neffects. We determine the Wilson flow scales $\\sqrt{t_{0,{\\rm\nph}}}=0.1449^{(7)}_{(9)}\\,$fm and $t_0^*\\approx t_{0,{\\rm ph}}$ from the octet\ncascade ($\\Xi$ baryon). Determining the light baryon spectrum in the continuum\nlimit, we find the nucleon mass $m_N=941.7^{(6.5)}_{(7.6)}\\,$MeV and the other\nstable baryon masses to agree with their experimental values within sub-percent\nlevel uncertainties. Moreover, we determine SU(3) and SU(2) chiral perturbation\ntheory low energy constants, including the octet and the $\\Omega$ baryon\nsigma~terms $\\sigma_{\\pi N}=43.9(4.7)\\,$MeV,\n$\\sigma_{\\pi\\Lambda}=28.2^{(4.3)}_{(5.4)}\\,$MeV,\n$\\sigma_{\\pi\\Sigma}=25.9^{(3.8)}_{(6.1)}\\,$MeV,\n$\\sigma_{\\pi\\Xi}=11.2^{(4.5)}_{(6.4)}\\,$MeV and\n$\\sigma_{\\pi\\Omega}=6.9^{(5.3)}_{(4.3)}\\,$MeV, as well as various parameters,\nrenormalization factors and improvement coefficients that are relevant for\nsimulations with our lattice action."
    },
    {
        "anchor": "Phase diagram of adjoint QCD at weak coupling and finite volume: The phase diagram of SU(N) gauge theories with fermions in an arbitrary\nrepresentation R can be calculated on finite volume manifolds such as S^1 x\nS^3. When S^3 is small a perturbative analysis is possible and the\nweak-coupling analogue of the pure Yang-Mills theory confinement-deconfinement\ntransition is accessible in the large N limit. We calculate the large N phase\ndiagram of adjoint QCD [SU(N) gauge theory with adjoint fermions] where\nperiodic boundary conditions are applied to fermions on S^1 such that the\nconfined phase is favored for light enough adjoint fermion mass. We calculate\nthe value of the mass times the radius of S^3 below which the confined phase is\nfavored for all volumes of S^1 / S^3 and discuss the implications for large N\nvolume reduction. We calculate also the phase diagram for N = 3 and compare\nwith recent lattice results.",
        "positive": "Non-perturbative determination of quark masses in quenched lattice QCD\n  with the Kogut-Susskind fermion action: We report results of quark masses in quenched lattice QCD with the\nKogut-Susskind fermion action, employing the Reguralization Independent scheme\n(RI) of Martinelli et al. to non-perturbatively evaluate the renormalization\nfactor relating the bare quark mass on the lattice to that in the continuum.\nCalculations are carried out at \\beta=6.0, 6.2, and 6.4, from which we find\n$m^{\\bar{MS}}_{ud} (2 GeV)= 4.23(29) MeV$ for the average up and down quark\nmass and, with the $\\phi$ meson mass as input, $m^{\\bar{MS}}_{s} (2 GeV)=\n129(12) MeV$ for the strange mass in the continuum limit. These values are\nabout 20% larger than those obtained with the one-loop perturbative\nrenormalization factor."
    },
    {
        "anchor": "Square Symanzik action to one-loop order: We present the one-loop coefficients for an alternative Symanzik improved\nlattice action with gauge groups SU(2) or SU(3).",
        "positive": "Finite-volume Hamiltonian method for $\u03c0\u03c0$ scattering in lattice QCD: Within a formulation of $\\pi\\pi$ scattering, we investigate the use of the\nfinite-volume Hamiltonian approach to resolving scattering observables from\nlattice QCD spectra. We consider spectra in the centre-of-mass and moving\nframes for both S- and P-wave cases. Furthermore, we investigate the\nmulti-channel case. Here we study the use of the Hamiltonian framework as a\nparametrization that can be fit directly to lattice spectra. Through this\nmethod, the hadron properties, such as mass, width and coupling, can be\ndirectly extracted from the lattice spectra."
    },
    {
        "anchor": "Classifying Topological Charge in SU(3) Yang-Mills Theory with Machine\n  Learning: We apply a machine learning technique for identifying the topological charge\nof quantum gauge configurations in four-dimensional SU(3) Yang-Mills theory.\nThe topological charge density measured on the original and smoothed gauge\nconfigurations with and without dimensional reduction is used as inputs for the\nneural networks (NN) with and without convolutional layers. The gradient flow\nis used for the smoothing of the gauge field. We find that the topological\ncharge determined at a large flow time can be predicted with high accuracy from\nthe data at small flow times by the trained NN; for example, the accuracy\nexceeds $99\\%$ with the data at $t/a^2\\le0.3$. High robustness against the\nchange of simulation parameters is also confirmed with a fixed physical volume.\nWe find that the best performance is obtained when the spatial coordinates of\nthe topological charge density are fully integrated out in preprocessing, which\nimplies that our convolutional NN does not find characteristic structures in\nmulti-dimensional space relevant for the determination of the topological\ncharge.",
        "positive": "Dynamical twisted mass fermions: We summarize four contributions about dynamical twisted mass fermions. The\nresulting report covers results for N_f=2 obtained from three different gauge\nactions, namely the standard Wilson plaquette gauge action, the DBW2 and the\ntree-level Symanzik improved gauge action. In addition, first results for\nN_f=2+1+1 flavours of twisted mass fermions are discussed."
    },
    {
        "anchor": "Coulomb Artifacts and Bottomonium Hyperfine Splitting in Lattice NRQCD: We study the role of the lattice artifacts associated with the Coulomb\nbinding effects in the analysis of the heavy quarkonium within lattice NRQCD.\nWe find that a \"naive\" perturbative matching generates spurious linear Coulomb\nartifacts, which result in a large systematic error in the lattice predictions\nfor the heavy quarkonium spectrum. This effect is responsible, in particular,\nfor the discrepancy between the recent determinations of the bottomonium\nhyperfine splitting in the radiatively improved lattice NRQCD [1, 2]. We show\nthat the correct matching procedure which provides full control over\ndiscretization errors is based on the asymptotic expansion of the lattice\ntheory about the continuum limit, which gives\n$M_{\\Upsilon(1S)}-M_{\\eta_b(1S)}=52.9\\pm 5.5~{\\rm MeV}$ [1].",
        "positive": "On the extraction of spectral densities from lattice correlators: Hadronic spectral densities are important quantities whose non-perturbative\nknowledge allows for calculating phenomenologically relevant observables, such\nas inclusive hadronic cross-sections and non-leptonic decay-rates. The\nextraction of spectral densities from lattice correlators is a notoriously\ndifficult problem because lattice simulations are performed in Euclidean time\nand lattice data are unavoidably affected by statistical and systematic\nuncertainties. In this paper we present a new method for extracting hadronic\nspectral densities from lattice correlators. The method allows for choosing a\nsmearing function at the beginning of the procedure and it provides results for\nthe spectral densities smeared with this function together with reliable\nestimates of the associated uncertainties. The same smearing function can be\nused in the analysis of correlators obtained on different volumes, such that\nthe infinite volume limit can be studied in a consistent way. While the method\nis described by using the language of lattice simulations, in reality it is\ncompletely general and can profitably be used to cope with inverse problems\narising in different fields of research."
    },
    {
        "anchor": "First results of baryon interactions from lattice QCD with physical\n  masses (1) -- General overview and two-nucleon forces --: We present the lattice QCD studies for baryon-baryon interactions for the\nfirst time with (almost) physical quark masses. $N_f = 2+1$ gauge\nconfigurations are generated with the Iwasaki gauge action and\nnonperturbatively $O(a)$-improved Wilson quark action with stout smearing on\nthe lattice of $(96 a)^4 \\simeq (8.2 {\\rm fm})^4$ with $a \\simeq 0.085$ fm,\nwhere $m_\\pi \\simeq 146$ MeV and $m_K \\simeq 525$ MeV. Baryon forces are\ncalculated from Nambu-Bethe-Salpeter (NBS) correlation functions using the\ntime-dependent HAL QCD method. In this report, we first give the general\noverview of the theoretical frameworks essential to the physical point\ncalculation of baryon forces. We then present the numerical results for the\ntwo-nucleon central and tensor forces in $^3S_1$-$^3D_1$ coupled channel and\nthe central force in $^1S_0$ channel. In particular, a clear signal is obtained\nfor the tensor force.",
        "positive": "Toward nuclear physics from lattice QCD on quantum computers: One of the ultimate missions of lattice QCD is to simulate atomic nuclei from\nthe first principle of the strong interaction. This is an extremely hard task\nfor the current computational technology, but might be reachable in coming\nquantum computing era. In this paper, we discuss the computational complexities\nof classical and quantum simulations of lattice QCD. It is shown that the\nquantum simulation scales better as a function of a nucleon number and thus\nwill outperform for large nuclei."
    },
    {
        "anchor": "Selected results on hadron structure using state-of-the-art lattice QCD\n  simulations: We review progress on hadron structure using lattice QCD simulations at or\nnear to physical values of the QCD parameters. In particular, we discuss recent\nresults on hadron masses, the nucleon charges, spin, gluon and quark\nunpolarized moments, the axial charge of hyperons, and the pion unpolarized\nmoment.",
        "positive": "Testing the self-duality of topological lumps in SU(3) lattice gauge\n  theory: We discuss a simple formula which connects the field-strength tensor to a\nspectral sum over certain quadratic forms of the eigenvectors of the lattice\nDirac operator. We analyze these terms for the near zero-modes and find that\nthey give rise to contributions which are essentially either self-dual or anti\nself-dual. Modes with larger eigenvalues in the bulk of the spectrum are more\ndominated by quantum fluctuations and are less (anti) self-dual. In the high\ntemperature phase of QCD we find considerably reduced (anti) self-duality for\nthe modes near the edge of the spectral gap."
    },
    {
        "anchor": "Determination of the $N_f=12$ step scaling function using M\u00f6bius\n  domain wall fermions: We calculate the renormalized step scaling function for twelve fundamental\nflavors nonperturbatively by determining the gradient flow coupling on gauge\nfield configurations generated with dynamical stout-smeared M\\\"obius domain\nwall fermions and Symanzik gauge action. Using Zeuthen, Symanzik, and Wilson\nflow we measure the energy density with three different operators. Our updated\nanalysis is based on up to five volume pairs ranging from L^4=8^4 up to 32^4.\nPredictions for the infinite volume extrapolated step scaling function based on\ndifferent flows and operators are mutually consistent. Our new results confirm\nthe previously observed significant discrepancy with staggered fermion\nsimulations in a wide range of the renormalized coupling.",
        "positive": "The $\u03b7$ and $\u03b7^\\prime$ mesons from Lattice QCD: The large mass of the ninth pseudoscalar meson, the $\\eta^\\prime$, is\nbelieved to arise from the combined effects of the axial anomaly and the gauge\nfield topology present in QCD. We report a realistic, 2+1 flavor, lattice QCD\ncalculation of the $\\eta$ and $\\eta^\\prime$ masses and mixing which confirms\nthis picture. The physical eigenstates show small octet-singlet mixing with a\nmixing angle of $\\theta = -14.1(2.8)^\\circ$. Extrapolation to physical light\nquark mass gives, with statistical errors only, $m_\\eta=573(6)$ MeV and\n$m_{\\eta^\\prime}=947(142)$ MeV, consistent with the experimental values of 548\nMeV and 958 MeV."
    },
    {
        "anchor": "QCD at Fixed Topology: Since present Monte Carlo algorithms for lattice QCD may become trapped in a\nfixed topological charge sector, it is important to understand the effect of\ncalculating at fixed topology. In this work, we show that although the\nrestriction to a fixed topological sector becomes irrelevant in the infinite\nvolume limit, it gives rise to characteristic finite size effects due to\ncontributions from all $\\theta$-vacua. We calculate these effects and show how\nto extract physical results from numerical data obtained at fixed topology.",
        "positive": "Nonperturbative improvement and tree-level correction of the quark\n  propagator: We extend an earlier study of the Landau gauge quark propagator in quenched\nQCD where we used two forms of the O(a)-improved propagator with the\nSheikholeslami-Wohlert quark action. In the present study we use the\nnonperturbative value for the clover coefficient c_sw and mean-field\nimprovement coefficients in our improved quark propagators. We compare this to\nour earlier results which used the mean-field c_sw and tree-level improvement\ncoefficients for the propagator. We also compare three different\nimplementations of tree-level correction: additive, multiplicative, and hybrid.\nWe show that the hybrid approach is the most robust and reliable and can\nsuccessfully deal even with strong ultraviolet behavior and zero-crossing of\nthe lattice tree-level expression. We find good agreement between our improved\nquark propagators when using the appropriate nonperturbative improvement\ncoefficients and hybrid tree-level correction. We also present a simple\nextrapolation of the quark mass function to the chiral limit."
    },
    {
        "anchor": "Topological Susceptibility of Yang-Mills Center Projection Vortices: The topological susceptibility induced by center projection vortices\nextracted from SU(2) lattice Yang-Mills configurations via the maximal center\ngauge is measured. Two different smoothing procedures, designed to eliminate\nspurious ultraviolet fluctuations of these vortices before evaluating the\ntopological charge, are explored. They result in consistent estimates of the\ntopological susceptibility carried by the physical thick vortices\ncharacterizing the Yang-Mills vacuum in the vortex picture. This susceptibility\nis comparable to the one obtained from the full lattice Yang-Mills\nconfigurations. The topological properties of the SU(2) Yang-Mills vacuum can\nthus be accounted for in terms of its vortex content.",
        "positive": "Behavior and finite-size effects of the sixth order cumulant in the\n  three-dimensional Ising universality class: The high-order cumulants of conserved charges are suggested to be sensitive\nobservables to search for the critical point of Quantum Chromodynamics (QCD).\nThis has been calculated to the sixth order in experiments. Corresponding\ntheoretical studies on the sixth order cumulant are necessary. Based on the\nuniversality of the critical behavior, we study the temperature dependence of\nthe sixth order cumulant of the order parameter using the parametric\nrepresentation of the three-dimensional Ising model, which is expected to be in\nthe same universality class as QCD. The density plot of the sign of the sixth\norder cumulant is shown on the temperature and external magnetic field plane.\nWe found that at non-zero external magnetic field, when the critical point is\napproached from the crossover side, the sixth order cumulant has a negative\nvalley. The width of the negative valley narrows with decreasing external\nfield. Qualitatively, the trend is similar to the result of Monte Carlo\nsimulation on a finite-size system. Quantitatively, the temperature of the sign\nchange is different. Through Monte Carlo simulation of the Ising model, we\ncalculated the sixth order cumulant of different sizes of systems. We discuss\nthe finite-size effects on the temperature at which the cumulant changes sign."
    },
    {
        "anchor": "QED with massive photons for precision physics: zero modes and first\n  result for the hadron spectrum: The current precision reached by lattice QCD calculations of low-energy\nhadronic observables, requires not only the introduction of electromagnetic\ncorrections, but also control over all the potential systematic uncertainties\nintroduced by the lattice version of QED. Introducing a massive photon as an\ninfrared regulator in lattice QED, provides a well defined theory, dubbed QEDM,\namenable to numerical evaluation [arXiv:1507.08916]. The photon mass is removed\nthrough extrapolation. In this contribution we scrutinise aspects of QEDM such\nas the presence and fate of the zero modes contributions and we describe the\ndetermination of the photon mass corrections in finite and infinite volume. We\ndemonstrate that the required extrapolations are well controlled using\nnumerical data obtained on two ensembles which only differ in volume.",
        "positive": "Nucleon strangeness form factors and moments of PDF: The calculation of the nucleon strangeness form factors from N_f=2+1 clover\nfermion lattice QCD is presented. Disconnected insertions are evaluated using\nthe Z(4) stochastic method, along with unbiased subtractions from the hopping\nparameter expansion. We find that increasing the number of nucleon sources for\neach configuration improves the signal significantly. We obtain G_M^s(0) =\n-0.017(25)(07), which is consistent with experimental values, and has an order\nof magnitude smaller error. Preliminary results for the strangeness\ncontribution to the second moment of the parton distribution function are also\npresented."
    },
    {
        "anchor": "A lattice study of light scalar tetraquarks: The observed mass pattern of scalar resonances below 1 GeV gives preference\nto the tetraquark assignment over the conventional $\\bar qq$ assignment for\nthese states. We present a search for tetraquarks with isospins 0, 1/2, 1 in\nlattice QCD, where the isospin channels 1/2 and 1 have not been studied before.\nWe determine three energy levels in each isospin channel using the variational\nmethod. The scattering states and possible tetraquark states are distinguished\nby considering the volume-dependence of spectral weights and by considering the\ntime-dependence of correlators near t~T/2. We find no indication for light\ntetraquarks at our range of pion masses 344-576 MeV.",
        "positive": "Controlling Excited-State Contamination in Nucleon Matrix Elements: We present a detailed analysis of methods to reduce statistical errors and\nexcited-state contamination in the calculation of matrix elements of quark\nbilinear operators in nucleon states. All the calculations were done on a 2+1\nflavor ensemble with lattices of size $32^3 \\times 64$ generated using the\nrational hybrid Monte Carlo algorithm at $a=0.081$~fm and with $M_\\pi=312$ MeV.\nThe statistical precision of the data is improved using the all-mode-averaging\nmethod. We compare two methods for reducing excited-state contamination: a\nvariational analysis and a two-state fit to data at multiple values of the\nsource-sink separation $t_{\\rm sep}$. We show that both methods can be tuned to\nsignificantly reduce excited-state contamination and discuss their relative\nadvantages and cost-effectiveness. A detailed analysis of the size of source\nsmearing used in the calculation of quark propagators and the range of values\nof $t_{\\rm sep}$ needed to demonstrate convergence of the isovector charges of\nthe nucleon to the $t_{\\rm sep} \\to \\infty $ estimates is presented."
    },
    {
        "anchor": "The Critical Hopping Parameter in O(a) improved Lattice QCD: We calculate the critical value of the hopping parameter, $\\kappa_c$, in O(a)\nimproved Lattice QCD, to two loops in perturbation theory. We employ the\nSheikholeslami-Wohlert (clover) improved action for Wilson fermions.\n  The quantity which we study is a typical case of a vacuum expectation value\nresulting in an additive renormalization; as such, it is characterized by a\npower (linear) divergence in the lattice spacing, and its calculation lies at\nthe limits of applicability of perturbation theory.\n  The dependence of our results on the number of colors $N$, the number of\nfermionic flavors $N_f$, and the clover parameter $c_{SW}$, is shown\nexplicitly. We compare our results to non perturbative evaluations of\n$\\kappa_c$ coming from Monte Carlo simulations.",
        "positive": "On the nature and order of the deconfining transition in QCD: The determination of the parameters of the deconfining transition in N_f=2\nQCD is discussed, and its relevance to the understanding of the mechanism of\ncolor confinement."
    },
    {
        "anchor": "A Chiral Solution to the Ginsparg-Wilson Equation: We present a chiral solution of the Ginsparg-Wilson equation. This work is\nmotivated by our recent proposal for nonperturbatively regulating chiral gauge\ntheories, where five-dimensional domain wall fermions couple to a\nfour-dimensional gauge field that is extended into the extra dimension as the\nsolution to a gradient flow equation. Mirror fermions at the far surface\ndecouple from the gauge field as if they have form factors that become\ninfinitely soft as the distance between the two surfaces is increased. In the\nlimit of an infinite extra dimension we derive an effective four-dimensional\nchiral overlap operator which is shown to obey the Ginsparg-Wilson equation,\nand which correctly reproduces a number of properties expected of chiral gauge\ntheories in the continuum.",
        "positive": "The model dependence of $m_\\varrho / f_\u03c0$: Should a strongly coupled composite Higgs boson scenario be realized in\nNature the most easily accessible experimental signal would be new particles\nmade up of the same ingredients as the Higgs but with different quantum\nnumbers. The lightest of these hypothetical new particles would probably be the\nvector mesons. In this contribution we report results on $m_\\varrho / f_\\pi$ in\nthe chiral-continuum limit with $SU(3)$ gauge group and $N_f = 2,3,4,5,6$\nflavors of fundamental fermions. In addition we compare $m_\\varrho / f_\\pi$\nresults from various models with different gauge groups and fermion content.\nThe main conclusion seems to be that the experimental measurement of this\nvector meson mass will be able to distinguish between gauge groups but less so\nbetween the fermion content."
    },
    {
        "anchor": "The $A^2$ asymmetry and propagators in lattice $SU(2)$ gluodynamics at\n  $T>T_c$: We study numerically the chromoelectric-chromomagnetic asymmetry of the\ndimension two $A^2$ gluon condensate as well as the transverse and longitudinal\ngluon propagators at $T>T_c$ in the Landau-gauge $SU(2)$ lattice gauge theory\nwith a particular emphasis on finite-volume effects. We show that previously\nfound so called symmetric point at which asymmetry changes sign is an artifact\nof the finite volume effects. We find that with increasing temperature the\nasymmetry decreases approaching zero value from above in agreement with\nperturbative result. Instead of the asymmetry we suggest the ratio of the\ntransverse to longitudinal propagator taken at zero momentum as an indicator of\nthe boundary of the postconfinement domain and find it at $T \\simeq 1.7 T_c$.",
        "positive": "Can Baryon Chiral Perturbation Theory be used to extrapolate lattice\n  data for the moment $\\langle x\\rangle_{u-d}$ of the nucleon?: We discuss the question in the title employing manifestly covariant Baryon\nChiral Perturbation Theory and recent high-statistics lattice results published\nin [1]."
    },
    {
        "anchor": "The string tension in the maximally Abelian gauge after smoothing: We apply smoothing to SU(2) lattice field configurations in 3+1 dimensions\nbefore fixing to the maximally Abelian gauge. The Abelian projected string\ntension is shown to be stable under this, whilst the monopole string tension\ndeclines by O(30%). Blocking of the SU(2) fields reduces this effect, but the\nuse of extended monopole definitions does not. We discuss these results in the\ncontext of additional confining excitations in the U(1) vacuum.",
        "positive": "Lattice QCD with 12 Degenerate Quark Flavors: We report on new data from additional zero temperature simulations of QCD\nwith 12 flavors. This is a continuation of previous studies using the DBW2\ngauge action and naive staggered fermions. With the use of the force gradient\nintegrator and a multiple-quark-mass preconditioned HMC, we have done\nsimulations with input quark masses from $m_q=0.003$ to $m_q=0.008$. We have\nobserved a metastable, first order, bulk transition that occurs at small input\nquark masses. As the quark mass increases, this first order bulk transition\nends at a second order critical point, and, for still heavier quark masses,\nbecomes the cross-over we have previously reported. We present measurements of\nhadron masses, decay constants and other low energy observables in the small\nquark mass region on the weak coupling side of the bulk transition. Our results\nshow that the behavior of the system is still consistent with spontaneously\nbroken chiral symmetry. We also discuss a preliminary investigation into the\nbehavior of the bulk transition itself. We have found that, as the system\napproaches the second order critical end point, the scalar singlet meson\nbecomes lighter. Thus it appears that the critical endpoint corresponds to a\ncontinuum limit theory only involving scalars and, following known triviality\narguments, this is likely a free field theory. The presence of this critical\nendpoint could influence scaling of lattice observables in the conventional\ncontinuum limit."
    },
    {
        "anchor": "A study of the phase transition in 4D pure compact U(1) LGT on toroidal\n  and spherical lattices: We have performed a systematic study of the phase transition in the pure\ncompact U(1) lattice gauge theory in the extended coupling parameter space\n(\\beta, \\gamma) on toroidal and spherical lattices. The observation of a\nnon-zero latent heat in both topologies for all investigated \\gamma in the\ninterval [+0.2,-0.4], together with an effective exponent \\nu = 1/d when large\nenough lattices are considered, lead us to conclude that the phase transition\nis first order. For negative \\gamma, our results point to an increasingly weak\nfirst order transition as \\gamma is made more negative.",
        "positive": "Quantum Finite Elements for Lattice Field Theory: Viable non-perturbative methods for lattice quantum field theories on curved\nmanifolds are difficult. By adapting features from the traditional finite\nelement methods (FEM) and Regge Calculus, a new simplicial lattice Quantum\nFinite Element (QFE) Lagrangian is constructed for fields on a smooth Riemann\nmanifold. To reach the continuum limit additional counter terms must be\nconstructed to cancel the ultraviolet distortions. This is tested by the\ncomparison of phi 4-th theory at the Wilson-Fisher fixed point with the exact\nIsing (c =1/2) CFT on a 2D Riemann sphere. The Dirac equation is also\nconstructed on a simplicial lattice approximation to a Riemann manifold by\nintroducing a lattice vierbein and spin connection on each link. Convergence of\nthe QFE Dirac equation is tested against the exact solution for the 2D Riemann\nsphere. Future directions and applications to Conformal Field Theories are\nsuggested."
    },
    {
        "anchor": "Critical behavior in a quasi D dimensional spin model: We study a classical spin model (more precisely a class of models) with O(N)\nsymmetry that can be viewed as a simplified $D$ dimensional lattice model. It\nis equivalent to a non-translationinvariant one dimensional model and contains\nthe dimensionality $D$ as a parameter that need not be an integer. The critical\ndimension turns out to be 2, just as in the usual translation invariant models.\nWe study the phase structure, critical phenomena and spontaneous symmetry\nbreaking. Furthermore we compute the perturbation expansion to low order with\nvarious boundary conditions. In our simplified models a number of questions can\nbe answered that remain controversial in the translation invariant models, such\nas the asymptoticity of the perturbation expansion and the role of\nsuper-instantons. We find that perturbation theory produces the right\nasymptotic expansion in dimension $D\\leq 2$ only with special boundary\nconditions. Finally the model allows a test of the percolation ideas of\nPatrascioiu and Seiler.",
        "positive": "Phase diagram of QCD at finite temperature and chemical potential from\n  lattice simulations with dynamical Wilson quarks: We present the first results for lattice QCD at finite temperature $T$ and\nchemical potential $\\mu$ with four flavors of Wilson quarks. The calculations\nare performed using the imaginary chemical potential method at $\\kappa=0$,\n0.001, 0.15, 0.165, 0.17 and 0.25, where $\\kappa$ is the hopping parameter,\nrelated to the bare quark mass $m$ and lattice spacing $a$ by\n$\\kappa=1/(2ma+8)$. Such a method allows us to do large scale Monte Carlo\nsimulations at imaginary chemical potential $\\mu=i \\mu_I$. By analytic\ncontinuation of the data with $\\mu_I < \\pi T/3$ to real values of the chemical\npotential, we expect at each $\\kappa\\in [0,\\kappa_{chiral}]$, a transition line\non the $(\\mu, T)$ plane, in a region relevant to the search for quark gluon\nplasma in heavy-ion collision experiments. The transition is first order at\nsmall or large quark mass, and becomes a crossover at intermediate quark mass."
    },
    {
        "anchor": "The Phase Transition to the Quark Gluon Plasma: Recent Results from\n  Lattice Calculations: We will discuss here some of the recent results obtained from lattice\nsimulations of QCD at non-zero temperature. Such calculations aim at a\nquantitative understanding of the thermodynamics of strongly interacting matter\nin equilibrium. We concentrate on a discussion of the equation of state, the\nchiral transition in two-flavour QCD and hadronic properties related to chiral\nsymmetry restoration in the vicinity of $T_c$.",
        "positive": "Deconfinement and Chiral Symmetry Restoration: We discuss the critical behaviour of strongly interacting matter close to the\nQCD phase transition. Emphasis is put on a presentation of results from lattice\ncalculations that illustrate deconfining as well as chiral symmetry restoring\nfeatures of the phase transition. We show that both transitions coincide in QCD\nwhile they fall apart in an SU(3) gauge theory coupled to adjoint fermions. We\nalso discuss some results on deconfinement in quenched QCD at non-zero baryon\nnumber."
    },
    {
        "anchor": "Heavy to light vector meson semileptonic decays: New (preliminary) results for the form factors relevant for the semileptonic\ndecays of heavy pseudoscalar to a light vector meson are presented. In\nparticular, we discuss the form factors for D --> K* and B --> rho modes.",
        "positive": "Investigating the critical properties of beyond-QCD theories using Monte\n  Carlo Renormalization Group matching: Monte Carlo Renormalization Group (MCRG) methods were designed to study the\nnon-perturbative phase structure and critical behavior of statistical systems\nand quantum field theories. I adopt the 2-lattice matching method used\nextensively in the 1980's and show how it can be used to predict the existence\nof non-perturbative fixed points and their related critical exponents in many\nflavor SU(3) gauge theories. This work serves to test the method and I study\nrelatively well understood systems: the $N_f=0$, 4 and 16 flavor models. The\npure gauge and $N_f=4$ systems are confining and chirally broken and the MCRG\nmethod can predict their bare step scaling functions. Results for the $N_f=16$\nmodel indicate the existence of an infrared fixed point with nearly marginal\ngauge coupling. I present preliminary results for the scaling dimension of the\nmass at this new fixed point."
    },
    {
        "anchor": "True or Fictitious Flattening? -MEM and the $\u03b8$ Term-: We study the sign problem in lattice field theory with a $\\theta$ term. We\napply the maximum entropy method (MEM) to flattening phenomenon of the free\nenergy density $f(\\theta)$, which originates from the sign problem. In our\nprevious paper, we applied the MEM by employing the Gaussian topological charge\ndistribution $P(Q)$ as mock data. In the present paper, we consider models in\nwhich `true' flattening of $f(\\theta)$ occurs. These may be regarded as good\nexamples for studying whether the MEM could correctly detect non trivial phase\nstructure.",
        "positive": "Non-equilibration of topological charge and its effects: In QCD simulations at small lattice spacings, the topological charge Q\nevolves very slowly and, if this quantity is not properly equilibrated, we\ncould get incorrect results for physical quantities, or incorrect estimates of\ntheir errors. We use the known relation between the dependence of masses and\ndecay constants on the QCD vacuum angle theta and the squared topological\ncharge Q^2 together with chiral perturbation theory results for the dependence\nof masses and decay constants on theta to estimate the size of these effects\nand suggest strategies for dealing with them. For the partially quenched case,\nwe sketch an alternative derivation of the known $\\chi$PT results of Aoki and\nFukaya, using the nonperturbatively correct chiral theory worked out by\nGolterman, Sharpe and Singleton, and by Sharpe and Shoresh. With the MILC\ncollaboration's ensembles of lattices with four flavors of HISQ dynamical\nquarks, we measure the $Q^2$ dependence of masses and decay constants and\ncompare to the $\\chi$PT forms. The observed agreement gives us confidence that\nwe can reliably estimate the errors from slow topology change, and even correct\nfor its leading effects."
    },
    {
        "anchor": "Relation between scattering amplitude and Bethe-Salpeter wave function\n  in quantum field theory: We reexamine the relations between the Bethe-Salpeter (BS) wave function of\ntwo particles, the on-shell scattering amplitude, and the effective potential\nin quantum filed theory. It is emphasized that there is an exact relation\nbetween the BS wave function inside the interaction range and the scattering\namplitude, and the reduced BS wave function, which is defined in this article,\nplays an essential role in this relation. Based on the exact relation, we show\nthat the solution of Schr\\\"odinger equation with the effective potential gives\nus a correct on-shell scattering amplitude only at the momentum where the\neffective potential is calculated, while wrong results are obtained from the\nSchr\\\"odinger equation at general momenta. We also discuss about a momentum\nexpansion of the reduced BS wave function and an uncertainty of the scattering\namplitude stemming from the choice of the interpolating operator in the BS wave\nfunction. The theoretical conclusion obtained in this article could give hints\nto understand the inconsistency observed in lattice QCD calculation of the\ntwo-nucleon channels with different approaches.",
        "positive": "Towards the Continuum Limit of the Overlap Quark Propagator in Landau\n  Gauge: The properties of the momentum space quark propagator in Landau gauge are\nexamined for the overlap quark action in quenched lattice QCD. Numerical\ncalculations were done on two lattices with different lattice spacing $a$ and\nsimilar physical volumes to explore the quark propagator in the continuum\nlimit. We have calculated the nonperturbative wavefunction renormalization\nfunction $Z(p)$ and the nonperturbative mass function $M(p)$ for a variety of\nbare quark masses and perform a simple linear extrapolation to the chiral\nlimit. We find the behaviour of $Z(p)$ and $M(p)$ in the chiral limit are in\ngood agreement between the two lattices."
    },
    {
        "anchor": "Theta dependence of the deconfinement temperature in Yang-Mills theories: We determine the theta dependence of the deconfinement temperature of SU(3)\npure gauge theory, finding that it decreases in presence of a topological theta\nterm. We do that by performing lattice simulations at imaginary theta, then\nexploiting analytic continuation. We also give an estimate of such dependence\nin the limit of a large number of colors N, and compare it with our numerical\nresults.",
        "positive": "Improving the Quark Number Susceptibilities for Staggered Fermions: Quark number susceptibilities approach their ideal gas limit at sufficiently\nhigh temperatures. As in the case of other thermodynamic quantities, this limit\nitself is altered substantially on lattices with small temporal extent, N_t =\n4-8, making it thus difficult to check the validity of perturbation theory.\nUnlike other observables, improving susceptibilities or number densities is\nsubject to constraints of current conservation and absence of chemical\npotential dependent divergences. We construct such an improved number density\nand susceptibility for staggered fermions and show that they approximate the\ncontinuum ideal gas limit better on small temporal lattices."
    },
    {
        "anchor": "Comment on ``Antiferromagnetic Potts Models'': We show that the Wang-Swendsen-Koteck\\'y algorithm for antiferromagnetic\n$q$-state Potts models is nonergodic at zero temperature for $q=3$ on periodic\n$3m \\times 3n$ lattices where $m,n$ are relatively prime. For $q \\ge 4$ and/or\nother lattice sizes or boundary conditions, the ergodicity at zero temperature\nis an open question.",
        "positive": "QCD at non-zero density and canonical partition functions with Wilson\n  fermions: We present a reduction method for Wilson Dirac fermions with non-zero\nchemical potential which generates a dimensionally reduced fermion matrix. The\nsize of the reduced fermion matrix is independent of the temporal lattice\nextent and the dependence on the chemical potential is factored out. As a\nconsequence the reduced matrix allows a simple evaluation of the Wilson fermion\ndeterminant for any value of the chemical potential and hence the exact\nprojection to the canonical partition functions."
    },
    {
        "anchor": "Static force from the lattice: We present a novel approach to compute the force between a static quark and a\nstatic antiquark from lattice gauge theory directly, rather than extracting it\nfrom the static energy. We explore this approach for SU(3) pure gauge theory\nusing the multilevel algorithm and smeared operators.",
        "positive": "Skewness, kurtosis and the 5th and 6th order cumulants of net\n  baryon-number distributions from lattice QCD confront high-statistics STAR\n  data: We present new results on up to $6^{th}$ order cumulants of net baryon-number\nfluctuations at small values of the baryon chemical potential, $\\mu_B$,\nobtained in lattice QCD calculations with physical values of light and strange\nquark masses. Representation of the Taylor expansions of higher order cumulants\nin terms of the ratio of the two lowest order cumulants,\n$M_B/\\sigma_B^2=\\chi_1^B(T,\\mu_B)/\\chi_2^B(T,\\mu_B)$, allows for a parameter\nfree comparison with data on net proton-number cumulants obtained by the STAR\nCollaboration in the Beam Energy Scan at RHIC. We show that recent high\nstatistics data on skewness and kurtosis ratios of net proton-number\ndistributions, obtained at beam energy $\\sqrt{s_{_{NN}}}=54.4$ GeV, agree well\nwith lattice QCD results on cumulants of net baryon-number fluctuations close\nto the pseudo-critical temperature, $T_{pc}(\\mu_B)$, for the chiral transition\nin QCD. We also present first results from a next-to-leading order expansion of\n$5^{th}$ and $6^{th}$ order cumulants on the line of pseudo-critical\ntemperatures."
    },
    {
        "anchor": "Effective sigma models and lattice Ward identities: We perform a lattice analysis of the Faddeev-Niemi effective action\nconjectured to describe the low-energy sector of SU(2) Yang-Mills theory. To\nthis end we generate an ensemble of unit vector fields (\"color spins\") n from\nthe Wilson action. The ensemble does not show long-range order but exhibits a\nmass gap of the order of 1 GeV. From the distribution of color spins we\nreconstruct approximate effective actions by means of exact lattice\nSchwinger-Dyson and Ward identities (\"inverse Monte Carlo\"). We show that the\ngenerated ensemble cannot be recovered from a Faddeev-Niemi action, modified in\na minimal way by adding an explicit symmetry-breaking term to avoid the\nappearance of Goldstone modes.",
        "positive": "Chiral phase transition of (2 + 1)-flavor QCD on $N_\u03c4 = 6$ lattices: We present updated studies on the chiral phase transition in $N_{f}=2+1$ QCD.\nSimulations have been carried out using Highly Improved Staggered Quarks (HISQ)\non lattices with temporal extent $N_{\\tau} = 6$ at vanishing baryon chemical\npotential. We updated our previous study \\cite{Ding:2015pmg} by extending the\ntemperature window from (140 MeV, 150 MeV) to (140 MeV, 170 MeV). The strange\nquark mass was chosen to its physical value $m_{s}^{\\mathrm{phy}}$, and five\nvalues of two degenerate light quark masses are varied from\n$m_{s}^{\\mathrm{phy}}/80$ to $m_{s}^{\\mathrm{phy}}/20$ which correspond to a\nGoldstone pion mass ranging from 80 MeV to 160 MeV in the continuum limit. The\nuniversal scaling behaviour of the QCD chiral phase transition is investigated\nby studying the temperature and quark mass dependences of chiral condensates\nand chiral susceptibilities. The window of criticality compared to previous\nstudies is also discussed."
    },
    {
        "anchor": "Singlet Mesons in Dark $Sp(4)$ Theories: We explore some aspects of $Sp(4)$ gauge theory with two fundamental fermions\nin the context of composite Goldstone Dark Matter. We present preliminary\nlattice results for the mass of the pseudoscalar iso-singlet meson $\\eta'$\nusing unimproved Wilson fermions and the standard plaquette action. We find\nthat the $\\eta'$ is slightly heavier than the pseudoscalar non-singlets $\\pi$\nand lighter than the vector mesons $\\rho$ for multiple ensembles with\n$m_\\pi/m_\\rho \\geq 0.77$. This pattern is potentially relevant for Beyond the\nStandard Model physics model building. Furthermore, we show that for $N_f=1+1$\nflavours the disconnected contributions to the unflavoured pseudoscalar $\\pi^0$\nare small. We supplement this measurement by a calculation of the $\\pi\\pi$\nscattering length $a_0$ which shows that the ensemble studied might be\nphenomenologically relevant for Dark Matter models such as the Strongly\nInteracting Massive Particles paradigm.",
        "positive": "Computation of the Heavy-Light Decay Constant with NRQCD: Non-relativistic QCD is applied for a lattice computation of the heavy-light\nmeson decay constant in quenched approximation at $\\beta=6.0$. Clear signals\nare obtained for the ground state at large times in the correlators, allowing a\nreliable extraction of the decay constant. Estimating the current\nrenormalization factor by the tadpole improvement procedure, we find $f_{B}=$\n164(17) MeV for the $B$ meson with $a^{-1}=$ 2.3 GeV, while an extrapolation to\nthe static limit yields $f_{B}^{\\mbox{static}}=$ 247(26) MeV."
    },
    {
        "anchor": "Magnetic field production after inflation: We study the electromagnetic field production during preheating after hybrid\ninflation in a model with the field content of the Standard Model, coupled to a\nsinglet inflaton. We find that very soon after symmetry breaking our system\nenters a regime of kinetic turbulence, characterized by a self-similar\nbehaviour of the energy spectra and a power-like dependence on time of the\ninflaton and Higgs field variances.",
        "positive": "Distribution Amplitudes of $K^*$ and $\u03c6$ at Physical Pion Mass from\n  Lattice QCD: We present the first lattice QCD calculation of the distribution amplitudes\nof longitudinally and transversely polarized vector mesons $K^*$ and $\\phi$\nusing large momentum effective theory. We use the clover fermion action on\nthree ensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ)\naction, generated by MILC collaboration, at physical pion mass and \\{0.06,\n0.09, 0.12\\} fm lattice spacings, and choose three different hadron momenta\n$P_z=\\{1.29, 1.72, 2.15\\}$ GeV. The resulting lattice matrix elements are\nnonperturbatively renormalized in a hybrid scheme proposed recently. An\nextrapolation to the continuum and infinite momentum limit is carried out. We\nfind that while the longitudinal distribution amplitudes tend to be close to\nthe asymptotic form, the transverse ones deviate rather significantly from the\nasymptotic form. Our final results provide crucial {\\it ab initio} theory\ninputs for analyzing pertinent exclusive processes."
    },
    {
        "anchor": "Toolkit for staggered $\u0394S=2$ matrix elements: A recent numerical lattice calculation of the kaon mixing matrix elements of\ngeneral $\\Delta S=2$ four-fermion operators using staggered fermions relied on\ntwo auxiliary theoretical calculations. Here we describe the methodology and\npresent the results of these two calculations. The first concerns one-loop\nmatching coefficients between staggered lattice operators and the corresponding\ncontinuum operators. Previous calculations with staggered fermions have used a\nnon-standard regularization scheme for the continuum operators, and here we\nprovide the additional matching factors needed to connect to the standard\nregularization scheme. This is the scheme in which two-loop anomalous\ndimensions are known. We also observe that all previous calculations of this\noperator matching using staggered fermions have overlooked one matching step in\nthe continuum. This extra step turns out to have no impact on three of the five\noperators (including that relevant for $B_K$), but does affect the other two\noperators. The second auxiliary calculation concerns the two-loop\nrenormalization group (RG) evolution equations for the $B$-parameters of the\n$\\Delta S=2$ operators. For one pair of operators, the standard analytic\nsolution to the two-loop RG equations fails due to a spurious singularity\nintroduced by the approximations made in the calculation. We give a\nnon-singular expression derived using analytic continuation, and check the\nresult using a numerical solution to the RG equations. We also describe the RG\nevolution for \"golden\" combinations of $B$-parameters, and give numerical\nresults for RG evolution matrices needed in the companion lattice calculation.",
        "positive": "Ordering monomial factors of polynomials in the product representation: The numerical construction of polynomials in the product representation (as\nused for instance in variants of the multiboson technique) can become\nproblematic if rounding errors induce an imprecise or even unstable evaluation\nof the polynomial. We give criteria to quantify the effects of these rounding\nerrors on the computation of polynomials approximating the function $1/s$. We\nconsider polynomials both in a real variable $s$ and in a Hermitian matrix. By\ninvestigating several ordering schemes for the monomials of these polynomials,\nwe finally demonstrate that there exist orderings of the monomials that keep\nrounding errors at a tolerable level."
    },
    {
        "anchor": "Lattice studies of supersymmetric gauge theories: Supersymmetry plays prominent roles in the study of quantum field theory and\nin many proposals for potential new physics beyond the standard model. Lattice\nfield theory provides a non-perturbative regularization suitable for strongly\ninteracting systems. This invited review briefly summarizes significant recent\nprogress in lattice investigations of supersymmetric field theories, as well as\nsome of the challenges that remain to be overcome. I focus on progress in three\nareas: supersymmetric Yang--Mills (SYM) theories in fewer than four space-time\ndimensions, as well as both minimal N=1 SYM and maximal N=4 SYM in four\ndimensions. I also highlight superQCD and sign problems as prominent challenges\nthat will be important to address in future work.",
        "positive": "Nonperturbative study of dynamical SUSY breaking in $\\mathcal{N} = (2,\n  2)$ Yang-Mills: We examine the possibility of dynamical supersymmetry breaking in\ntwo-dimensional $\\mathcal{N} = (2, 2)$ supersymmetric Yang-Mills theory. The\ntheory is discretized on a Euclidean spacetime lattice using a supersymmetric\nlattice action. We compute the vacuum energy of the theory at finite\ntemperature and take the zero temperature limit. Supersymmetry will be\nspontaneously broken in this theory if the measured ground state energy is\nnon-zero. By performing simulations on a range of lattices up to $96 \\times 96$\nwe are able to perform a careful extrapolation to the continuum limit for a\nwide range of temperatures. Subsequent extrapolations to the zero temperature\nlimit yield an upper bound on the ground state energy density. We find the\nenergy density to be statistically consistent with zero in agreement with the\nabsence of dynamical supersymmetry breaking in this theory."
    },
    {
        "anchor": "Phase diagram of SU(2) with 2 flavors of dynamical adjoint quarks: We report on numerical simulations of SU(2) lattice gauge theory with two\nflavors of light dynamical quarks in the adjoint of the gauge group. The\ndynamics of this theory is thought to be very different from QCD -- the theory\nexhibiting conformal or near conformal behavior in the infrared. We make a high\nresolution survey of the phase diagram of this model in the plane of the bare\ncoupling and quark mass on lattices of size 8^3 \\times 16. Our simulations\nreveal a line of first order phase transitions extending from beta=0 to\nbeta=beta_c \\sim 2.0. For beta > beta_c the phase boundary is no longer first\norder but continues as the locus of minimum meson mass. For beta > 2.0 we\nobserve the pion and rho masses along the phase boundary to be light,\nindependent of bare coupling and approximately degenerate. We discuss possible\ninterpretations of these observations and corresponding continuum limits.",
        "positive": "Fermions obstruct dimensional reduction in hot QCD: We have studied, for the first time, screening masses obtained from\nglueball-like correlators in Quantum Chromodynamics with four light dynamical\nflavours of quarks in the temperature range 1.5T_c < T < 3T_c, where T_c is the\ntemperature at which the chiral transition occurs. We have also studied\npion-like and sigma-like screening masses, and found that they are degenerate\nin the entire range of T. These obstruct perturbative dimensional reduction\nsince the lowest glueball screening mass is heavier than them. Extrapolation of\nour results suggests that this obstruction may affect the entire range of\ntemperature expected to be reached even at the Large Hadron Collider."
    },
    {
        "anchor": "What Lattice QCD tell us about the Landau Gauge Infrared Propagators: The calculation of the Landau gauge gluon propagator performed in Coimbra\nusing lattice QCD simulations is reviewed. Particular attention is given to the\nbehavior of the gluon propagator in the infrared region and the value of\n$D(0)$. In the second part of the article, the modeling of the lattice data\nusing massive type propagators and Gribov type propagators is discussed. Four\ndifferent mass scales are required to describe the propagator over the full\nrange of momenta accessed by the simulations discussed here. Furthermore,\nassuming a momentum dependent gluon mass, we sketch on its functional\ndependence.",
        "positive": "Topological susceptibility in 2-flavor lattice QCD with fixed topology: We determine the topological susceptibility $ \\chi_t $ in the trivial\ntopological sector generated by lattice simulations of two-flavor QCD with\noverlap Dirac fermion, on a $16^3 \\times 32$ lattice with lattice spacing\n$\\sim$ 0.12 fm, at six sea quark masses $m_q$ ranging from $m_s/6$ to $m_s$\n(where $m_s$ is the physical strange quark mass). The $ \\chi_t $ is extracted\nfrom the plateau (at large time separation) of the time-correlation function of\nthe flavor-singlet pseudoscalar meson ($\\eta'$), which arises from the finite\nsize effect due to fixed topology. In the small $m_q$ regime, our result of\n$\\chi_t$ is proportional to $m_q$ as expected from chiral effective theory.\nUsing the formula $\\chi_t=m_q\\Sigma/N_f$ by Leutwyler-Smilga, we obtain the\nchiral condensate in $N_f=2$ QCD as $\\Sigma^{\\bar{\\mathrm{MS}}}(\\mathrm{2\nGeV})=[252(5)(10) \\mathrm{MeV}]^3 $, in good agreement with our previous result\nobtained in the $\\epsilon$-regime."
    },
    {
        "anchor": "$I=2$ $\u03c0\u03c0$ scattering phase shift from the HAL QCD method with the\n  LapH smearing: Physical observables, such as the scattering phase shifts and the binding\nenergies, calculated from the non-local HAL QCD potential do not depend on the\nsink operators used to define the potential. This is called the scheme\nindependence of the HAL QCD method. In practical applications, the derivative\nexpansion of the non-local potential is employed, so that physical observables\nmay receive some scheme dependence at given order of the expansion. In this\npaper, we compare the $I=2$ $\\pi\\pi$ scattering phase shifts obtained in the\npoint-sink scheme (the standard scheme in the HAL QCD method) and the\nsmeared-sink scheme (the LapH smearing newly introduced in the HAL QCD method).\nAlthough potentials in different schemes have different forms as expected, we\nfind that, for reasonably small smearing size, the resultant scattering phase\nshifts agree with each other if the next-to-leading order (NLO) term is taken\ninto account. We also find that the HAL QCD potential in the point-sink scheme\nhas negligible NLO term for wide range of energies, which implies a good\nconvergence of the derivative expansion in this case, while the potential in\nthe smeared-sink scheme has non-negligible NLO contribution. Implication of\nthis observation to the future studies of resonance channels (such as the $I=0$\nand $1$ $\\pi\\pi$ scatterings) with smeared all-to-all propagators is briefly\ndiscussed. All computations in this paper have been performed at the lattice\nspacing $a\\simeq 0.12$ fm ($1/a \\simeq 1.6$ GeV) on a $16^3\\times 32$ lattice\nwith the pion mass $m_\\pi\\simeq 870$ MeV.",
        "positive": "Non-perturbative Heavy Quark Effective Theory: An application to\n  semi-leptonic B-decays: We review a lattice strategy how to non-perturbatively determine the\ncoefficients in the HQET expansion of all components of the heavy-light axial\nand vector currents, including 1/m_h-corrections. We also discuss recent\npreliminary results on the form factors parameterizing semi-leptonic B-decays\nat the leading order in 1/m_h."
    },
    {
        "anchor": "The Stefan-Boltzmann law in a small box and the pressure deficit in hot\n  SU(N) lattice gauge theory: The blackbody radiation in a box L^3 with periodic boundary conditions in\nthermal equilibrium at a temperature T is affected by finite-size effects.\nThese bring about modifications of the thermodynamic functions which can be\nexpressed in a closed form in terms of the dimensionless parameter LT. For\ninstance, when LT~4 - corresponding to the value where the most reliable SU(N)\ngauge lattice simulations have been performed above the deconfining temperature\nT_c - the deviation of the free energy density from its thermodynamic limit is\nabout 5%. This may account for almost half of the pressure deficit observed in\nlattice simulations at T~ 4 T_c.",
        "positive": "A new fermion Hamiltonian for lattice gauge theory: We formulate Hamiltonian vector-like lattice gauge theory using the overlap\nformula for the spatial fermionic part, $H_f$. We define a chiral charge, $Q_5$\nwhich commutes with $H_f$, but not with the electric field term. There is an\ninteresting relation between the chiral charge and the fermion energy with\nconsequences for chiral anomalies."
    },
    {
        "anchor": "SU(2) vacuum dynamics in applied external magnetic field: The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a\ngauge-invariant effective action, both at zero and finite temperature. Working\nwith lattices up to 32^4 we check the scaling of the energy density with the\nmagnetic length. We find that the screening at zero temperature of the applied\nexternal magnetic field weakens by increasing the temperature.",
        "positive": "Quenched Hadrons using Wilson and O(a)-Improved Fermion Actions at\n  beta=6.2: We present the first study of the light hadron spectrum and decay constants\nfor quenched QCD using an O(a)-improved nearest-neighbour Wilson fermion action\nat \\beta=6.2. We compare the results with those obtained using the standard\nWilson fermion action, on the same set of 18 gauge field configurations of a\n24^3 times 48 lattice. For pseudoscalar meson masses in the range 330-800 MeV,\nwe find no significant difference between the results for the two actions. The\nscales obtained from the string tension and mesonic sector are consistent, but\ndiffer from that derived from baryon masses. The ratio of the pseudoscalar\ndecay constant to the vector meson mass is roughly independent of quark mass as\nobserved experimentally, and in approximate agreement with the measured value."
    },
    {
        "anchor": "Higgs-Yukawa model in chirally-invariant lattice field theory: Non-perturbative numerical lattice studies of the Higgs-Yukawa sector of the\nstandard model with exact chiral symmetry are reviewed. In particular, we\ndiscuss bounds on the Higgs boson mass at the standard model top quark mass,\nand in the presence of heavy fermions. We present a comprehensive study of the\nphase structure of the theory at weak and very strong values of the Yukawa\ncoupling as well as at non-zero temperature.",
        "positive": "$|V_{cb}|$ using lattice QCD: Lattice QCD calculations of hadronic matrix elements allow one to draw\ninferences about quark flavor interactions from measurements of hadron decays.\nWithin the context of the Standard Model, the magnitude of the charm-bottom\nquark coupling $V_{cb}$ can be determined from semileptonic decays such as\n$B\\to D^{(*)}\\ell\\nu$. This brief review summarizes the present status and\nshort-term outlook for determining $|V_{cb}|$ using lattice QCD."
    },
    {
        "anchor": "Chiral symmetry restoration and axial vector renormalization for Wilson\n  fermions: Lattice gauge theories with Wilson fermions break chiral symmetry. In the\nU(1) axial vector current this manifests itself in the anomaly. On the other\nhand it is generally expected that the axial vector flavour mixing current is\nnon-anomalous. We give a short, but strict proof of this to all orders of\nperturbation theory, and show that chiral symmetry restauration implies a\nunique multiplicative renormalization constant for the current. This constant\nis determined entirely from an irrelevant operator in the Ward identity. The\nbasic ingredients going into the proof are the lattice Ward identity, charge\nconjugation symmetry and the power counting theorem. We compute the\nrenormalization constant to one loop order. It is largely independent of the\nparticular lattice realization of the current.",
        "positive": "Small eigenvalues of the SU(3) Dirac operator on the lattice and in\n  Random Matrix Theory: We have calculated complete spectra of the staggered Dirac operator on the\nlattice in quenched SU(3) gauge theory for \\beta = 5.4 and various lattice\nsizes. The microscopic spectral density, the distribution of the smallest\neigenvalue, and the two-point spectral correlation function are analyzed. We\nfind the expected agreement of the lattice data with universal predictions of\nthe chiral unitary ensemble of random matrix theory up to a certain energy\nscale, the Thouless energy. The deviations from the universal predictions are\ndetermined using the disconnected scalar susceptibility. We find that the\nThouless energy scales with the lattice size as expected from theoretical\narguments making use of the Gell-Mann--Oakes--Renner relation."
    },
    {
        "anchor": "Gluon Propagators in Linear Covariant Gauge: The implementation of the linear covariant gauge on the lattice faces a\nconceptual problem: using the standard compact discretization, the gluon field\nis bounded, while the four-divergence of the gluon field satisfies a Gaussian\ndistribution, i.e. it is unbounded. This can give rise to convergence problems\nwhen a numerical implementation is attempted. In order to overcome this\nproblem, one can use different discretizations for the gluon field or consider\nan SU(N_c) group with sufficiently large N_c. One can also consider small\nvalues of the gauge parameter xi and study numerically the limiting case of xi\n\\to 0, i.e. the Landau gauge. These different approaches will be discussed\nhere.",
        "positive": "Future of Chiral Extrapolations with Domain Wall Fermions: I discuss the constraints on the lattice spacing, a, the quark masses, m, the\nbox size, L, and particularly the residual mass, m_res, such that one can\nsuccessfully calculate phenomenologically interesting quantities using Domain\nWall fermions (DWF). The constraints on a, m, and L are largely common with\nother improved fermion discretizations, and I emphasize that the improved\nchiral symmetry of DWF does not remove the need for simulations with a\nsignificant range of lattice parameters. Concerning m_res, I compare the\nanalysis of chiral symmetry breaking to that with Wilson fermions, emphasizing\nthat DWF are better than simply Wilson fermions with each chiral symmetry\nbreaking effect reduced by a common factor. I then discuss the impact of\nnon-zero m_res both on generic hadronic quantities, and on matrix elements\nwhich involve mixing with lower dimension operators."
    },
    {
        "anchor": "Pseudo-random number generators for Monte Carlo simulations on Graphics\n  Processing Units: Basic uniform pseudo-random number generators are implemented on ATI Graphics\nProcessing Units (GPU). The performance results of the realized generators\n(multiplicative linear congruential (GGL), XOR-shift (XOR128), RANECU, RANMAR,\nRANLUX and Mersenne Twister (MT19937)) on CPU and GPU are discussed. The\nobtained speed-up factor is hundreds of times in comparison with CPU. RANLUX\ngenerator is found to be the most appropriate for using on GPU in Monte Carlo\nsimulations. The brief review of the pseudo-random number generators used in\nmodern software packages for Monte Carlo simulations in high-energy physics is\npresent.",
        "positive": "Light Hadron Masses from Lattice QCD: This article reviews lattice QCD results for the light hadron spectrum. We\ngive an overview of different formulations of lattice QCD, with discussions on\nthe fermion doubling problem and improvement programs. We summarize recent\ndevelopments in algorithms and analysis techniques, that render calculations\nwith light, dynamical quarks feasible on present day computer resources.\nFinally, we summarize spectrum results for ground state hadrons and resonances\nusing various actions."
    },
    {
        "anchor": "Vacuum Insertion Approximation and the $\u0394I=1/2$ rule:a lattice QCD\n  test of the na\u00efve factorization hypothesis for $K$, $D$, $B$ and static\n  mesons: Motivated by a recent paper by the RBC-UKQCD Collaboration, which observes\nlarge violations of the na\\\"ive factorization hypothesis in $K \\to \\pi \\pi$\ndecays, we study in this paper the accuracy of the Vacuum Insertion\nApproximation (VIA) for the matrix elements of the complete basis of four\nfermion $\\Delta F=2$ operators. We perform a comparison between the matrix\nelements in QCD, evaluated on the lattice, and the VIA predictions. We also\ninvestigate the dependence on the external meson masses by computing matrix\nelements for $K$, $D_s$, $B_s$ and static mesons. In commonly used\nrenormalization schemes, we find large violations of the VIA in particular for\none of the two relevant Wick contractions in the kaon sector. These deviations,\nhowever, decrease significantly as the meson mass increases and the VIA\npredictions turn out to be rather well verified for B-meson matrix elements\nand, even better, in the infinite mass limit.",
        "positive": "Error reduction technique using covariant approximation and application\n  to nucleon form factor: We demonstrate the new class of variance reduction techniques for hadron\npropagator and nucleon isovector form factor in the realistic lattice of\n$N_f=2+1$ domain-wall fermion. All-mode averaging (AMA) is one of the powerful\ntools to reduce the statistical noise effectively for wider varieties of\nobservables compared to existing techniques such as low-mode averaging (LMA).\nWe adopt this technique to hadron two-point functions and three-point\nfunctions, and compare with LMA and traditional source-shift method in the same\nensembles. We observe AMA is much more cost effective in reducing statistical\nerror for these observables."
    },
    {
        "anchor": "Low-lying Dirac eigenmodes and monopoles in 3+1D compact QED: We study the properties of low-lying Dirac modes in quenched compact QED at\n$\\beta =1.01$, employing $12^3\\times N_t$ ($N_t =4,6,8,10,12$) lattices and the\noverlap formalism for the fermion action. We pay attention to the spatial\ndistributions of low-lying Dirac modes below and above the ``phase transition\ntemperature'' $T_c$. Near-zero modes are found to have universal\nanti-correlations with monopole currents, and are found to lose their temporal\nstructures above $T_c$ exhibiting stronger spatial localization properties. We\nalso study the nearest-neighbor level spacing distribution of Dirac eigenvalues\nand find a Wigner-Poisson transition.",
        "positive": "Calculation of the nucleon sigma term and strange quark content with two\n  flavors of dynamical overlap fermions: We present a calculation of the nucleon sigma term on two-flavor QCD\nconfigurations with dynamical overlap fermions. We analyse the lattice data for\nthe nucleon mass using the baryon chiral perturbation theory. Using partially\nquenched data sets, we extract the connected and disconnected contributions to\nthe nucleon sigma term separately. Chiral symmetry on the lattice simplifies\nthe determination of the disconnected contribution. We find that the strange\nquark content, which determines the neutralino dark matter reaction rate with\nnucleon through the Higgs boson exchange, is much smaller than the previous\nlattice results."
    },
    {
        "anchor": "The behavior of the sextic coupling for the scalar field at the\n  intermediate and strong coupling regime: We study the behavior of the renormalized sextic coupling at the intermediate\nand strong coupling regime for the $\\phi^4 $ theory defined in $d=2$-dimension.\nWe found a good agreement with the results obtained by the field-theoretical\nrenormalization-group in the Ising limit. In this work we use the lattice\nregularization method.",
        "positive": "Perturbative renormalization of the supercurrent operator in lattice\n  ${\\cal N}{=}1$ supersymmetric Yang-Mills theory: In this work we perform a perturbative study of the Noether supercurrent\noperator in the context of Supersymmetric ${\\cal N}{=}1$ Yang-Mills (SYM)\ntheory on the lattice. The supercurrent mixes with several other operators,\nsome of which are not gauge invariant, having the same quantum numbers. We\ndetermine, to one loop order, the renormalization and all corresponding mixing\ncoefficients by computing relevant Green's functions of each one of the mixing\noperators with external elementary fields. Our calculations are performed both\nin dimensional and lattice regularization. From the first regularization we\nobtain the $\\bar{MS}$-renormalized Green's functions; comparison of the latter\nwith the corresponding Green's functions in the lattice regularization leads to\nthe extraction of the lattice renormalization factors and mixing coefficients\nin the $\\bar{MS}$ scheme. The lattice calculations are performed to lowest\norder in the lattice spacing, using Wilson gluons and clover improved gluinos.\nThe lattice results can be used in nonperturbative studies of supersymmetric\nWard identities."
    },
    {
        "anchor": "Computational Physics: An Introduction to Monte Carlo Simulations of\n  Matrix Field Theory: This book is divided into two parts. In the first part we give an elementary\nintroduction to computational physics consisting of 21 simulations which\noriginated from a formal course of lectures and laboratory simulations\ndelivered since 2010 to physics students at Annaba University. The second part\nis much more advanced and deals with the problem of how to set up working Monte\nCarlo simulations of matrix field theories which involve finite dimensional\nmatrix regularizations of noncommutative and fuzzy field theories, fuzzy spaces\nand matrix geometry. The study of matrix field theory in its own right has also\nbecome very important to the proper understanding of all noncommutative, fuzzy\nand matrix phenomena. The second part, which consists of 9 simulations, was\ndelivered informally to doctoral students who are working on various problems\nin matrix field theory. Sample codes as well as sample key solutions are also\nprovided for convenience and completness. An appendix containing an executive\narabic summary of the first part is added at the end of the book.",
        "positive": "Exact local fermionic zero modes: We introduce a simple method to find localized exact fermionic zero modes for\nany local fermionic action. The zero modes are attached to specific local gauge\nconfigurations. Examples are provided for staggered and Wilson fermion actions\nin 2-6 dimensions, at finite and infinite lattice volumes, and for abelian and\nnon-abelian gauge groups. One of our concrete results is that a finite density\nof almost zero modes must occur in quenched four dimensional lattice gauge\ntheory simulations that use traditional methods. This density is exponentially\nsuppressed in the gauge coupling constant."
    },
    {
        "anchor": "Nucleon Transverse Momentum-dependent Parton Distributions in Lattice\n  QCD: Renormalization Patterns and Discretization Effects: Lattice QCD calculations of transverse momentum-dependent parton distribution\nfunctions (TMDs) in nucleons are presented, based on the evaluation of nucleon\nmatrix elements of quark bilocal operators with a staple-shaped gauge\nconnection. Both time-reversal odd effects, namely, the generalized Sivers and\nBoer-Mulders transverse momentum shifts, as well as time-reversal even effects,\nnamely, the generalized transversity and one of the generalized worm-gear\nshifts are studied. Results are obtained on two different $n_f = 2+1$ flavor\nensembles with approximately matching pion masses but very different\ndiscretization schemes: domain-wall fermions (DWF) with lattice spacing\n$a=0.084$ fm and pion mass 297 MeV, and Wilson-clover fermions with $a=0.114$\nfm and pion mass 317 MeV. Comparison of the results on the two ensembles yields\ninsight into the length scales at which lattice discretization errors are\nsmall, and into the extent to which the renormalization pattern obeyed by the\ncontinuum QCD TMD operator continues to apply in the lattice formulation. For\nthe studied TMD observables, the results are found to be consistent between the\ntwo ensembles at sufficiently large separation of the quark fields within the\noperator, whereas deviations are observed in the local limit and in the case of\na straight link gauge connection, which is relevant to the studies of parton\ndistribution functions. Furthermore, the lattice estimates of the generalized\nSivers shift obtained here are confronted with, and are seen to tend towards, a\nphenomenological estimate extracted from experimental data.",
        "positive": "Progress in computing parton distribution functions from the quasi-PDF\n  approach: We discuss the current developments by the European Twisted Mass\nCollaboration in extracting parton distribution functions from the quasi-PDF\napproach. We concentrate on the non-perturbative renormalization prescription\nrecently developed by us, using the RI$'$ scheme. We show results for the\nrenormalization functions of matrix elements needed for the computation of\nquasi-PDFs, including the conversion to the $\\overline{\\rm MS}$ scheme, and for\nrenormalized matrix elements. We discuss the systematic effects present in the\n$Z$-factors and the possible ways of addressing them in the future."
    },
    {
        "anchor": "New chiral lattice actions of the Borici-Creutz type: We generalize the Borici-Creutz action in such a way that the position of the\nsecond zero and the direction which breaks the hypercubic symmetry can be\narbitrarily chosen, and the action has still the correct continuum limit.\nMinimal doubling is guaranteed if the distance between the two zeros does not\nbecome too large. Special values of this distance could turn out to be\nparticularly convenient for efficient numerical simulations of minimally\ndoubled fermions.",
        "positive": "$B_c$ Spectroscopy from Lattice QCD: We present first results for $B_c$ spectroscopy using Lattice\nNon-Relativistic QCD (NRQCD). For the NRQCD action the leading order\nspin-dependent and next to leading order spin-independent interactions have\nbeen included with tadpole-improved coefficients. We use multi-exponential fits\nto multiple correlation functions to extract ground and excited $S$ states and\ngive accurate values for the $S$ state hyperfine splitting and the P state\n($B^{**}_c$) fine structure, including the effects of $^1P_1/^3P_1$ mixing."
    },
    {
        "anchor": "Finite-volume spectrum of $\u03c0^+\u03c0^+$ and $\u03c0^+\u03c0^+\u03c0^+$ systems: The ab-initio understanding of hadronic three-body systems above threshold,\nsuch as exotic resonances or the baryon spectrum, requires the mapping of the\nfinite-volume eigenvalue spectrum, produced in lattice QCD calculations, to the\ninfinite volume. We present the first application of such a formalism to a\nphysical system in form of three interacting positively charged pions. The\nresults for the ground state energies agree with the available lattice QCD\nresults by the NPLQCD collaboration at unphysical pion masses. Extrapolations\nto physical pion masses are performed using input from effective field theory.\nThe excited energy spectrum is predicted. This demonstrates the feasibility to\ndetermine three-body amplitudes above threshold from lattice QCD, including\nresonance properties of axial mesons, exotics, and excited baryons.",
        "positive": "Instanton, Monopole and Confinement: We study the correlation between instantons and QCD-monopoles both in the\nlattice gauge theory and in the multi-instanton system using the maximally\nabelian gauge. First, we find the existence of an almost linear correlation\nbetween the total length of monopole trajectories and the total number of\npseudoparticles (instantons and anti-instantons) in the $16^{3}\\times4$ SU(2)\nlattice. Second, we study the features of QCD-monopole in the SU(2)\nmulti-instanton vacuum on the $16^{4}$ lattice as a random ensemble of\npseudoparticles. A signal of monopole condensation is found as the clustering\nof monopole trajectories, when the topological pseudoparticles is sufficiently\ndense."
    },
    {
        "anchor": "Higher order cumulants of net baryon-number distributions at non-zero\n  $\u03bc_B$: Using recent results on higher order cumulants of conserved charge\nfluctuations from lattice QCD, we construct mean, variance, skewness, kurtosis,\nhyper-skewness and hyper-kurtosis of net-baryon number distributions for small\nbaryon chemical potentials $\\mu_B$. For the strangeness neutral case\n($\\mu_S=0$) at fixed ratio of electric charge to baryon number density\n($\\frac{n_Q}{n_B}=0.4$), which is appropriate for a comparison with heavy ion\ncollisions, we present results for $\\kappa_B \\sigma_B^2$, $S_B \\sigma_B^3/M_B$,\n$\\kappa^{H}_{B}\\sigma_{B}^4$ and $S^{H}_{B}\\sigma^5_{B}/M_{B}$ on the crossover\nline for the chiral transition, $T_{pc}(\\mu_B)$. Continuum extrapolations for\nthis pseudo-critical transition line have recently been reported by HotQCD up\nto baryon chemical potentials $\\mu_B\\simeq 300$ MeV [arXiv:1812.08235]. These\ncumulant ratios are of direct relevance for comparisons with corresponding\nratios measured by STAR in the BES-I and II runs at beam energies\n$\\sqrt{s_{NN}}\\ge 20$ GeV. In particular, we point out that recent high\nstatistics results on skewness and kurtosis of net-baryon number distributions\nobtained by STAR at $\\sqrt{s_{NN}} = 54.4$ GeV put strong constraints on\nfreeze-out parameters and are consistent with predictions from thermal QCD.",
        "positive": "Chiral extrapolation of the leading hadronic contribution to the muon\n  anomalous magnetic moment: A lattice computation of the leading-order hadronic contribution to the muon\nanomalous magnetic moment can potentially help reduce the error on the Standard\nModel prediction for this quantity, if sufficient control of all systematic\nerrors affecting such a computation can be achieved. One of these systematic\nerrors is that associated with the extrapolation to the physical pion mass from\nvalues on the lattice larger than the physical pion mass. We investigate this\nextrapolation assuming lattice pion masses in the range of 200 to 400MeV with\nthe help of two-loop chiral perturbation theory, and find that such an\nextrapolation is unlikely to lead to control of this systematic error at the 1%\nlevel. This remains true even if various tricks to improve the reliability of\nthe chiral extrapolation employed in the literature are taken into account. In\naddition, while chiral perturbation theory also predicts the dependence on the\npion mass of the leading-order hadronic contribution to the muon anomalous\nmagnetic moment as the chiral limit is approached, this prediction turns out to\nbe of no practical use, because the physical pion mass is larger than the muon\nmass that sets the scale for the onset of this behavior."
    },
    {
        "anchor": "Investigation of the $U_A(1)$ in high temperature QCD on the lattice: In this project we study the effect of the $U_A(1)$ anomaly for (2+1)-flavour\nQCD at high temperature. We apply the overlap operator as a tool to probe the\ntopological properties of gauge field configurations which have been generated\nwithin the Highly Improved Staggered Quark (HISQ) discretization scheme on\nlattices of size $32^3\\times 8$ with $m_l/m_s=1/20$, commonly used for the\nstudy of QCD thermodynamics. Although we have at present, only results for one\nvalue of the quark masses and thus cannot monitor the change of the eigenvalue\ndistributions with the light quark mass, the distribution of the low-lying\neigenvalues of the overlap operator suggests that the $U_A(1)$ is not restored\neffectively even at 1.5 times the pseudo critical temperature. The\ncorresponding low-lying eigenmodes show localization properties.",
        "positive": "Non-perturbative renormalization of the axial current with dynamical\n  Wilson fermions: We present a new normalization condition for the axial current, derived from\nthe PCAC relation with non-vanishing quark mass. This condition is expected to\nreduce mass effects in the chiral extrapolation of the results for the\nnormalization factor Z_A. The application to the two-flavor theory with\nimproved Wilson fermions shows that this expectation is indeed fulfilled. Using\nthe Schroedinger functional setup we calculate Z_A(g_0^2) as well as the vector\ncurrent normalization factor Z_V(g_0^2) for beta = 6/g_0^2 >= 5.2."
    },
    {
        "anchor": "The deconfinement phase transition in $Sp(2N)$ gauge theories and the\n  density of states method: First-order phase transitions in the early universe might produce a\ndetectable background of gravitational waves. As these phase transitions can be\ngenerated by new physics, it is important to quantify these effects. Many pure\nYang-Mills gauge theories are known to undergo first-order deconfinement phase\ntransitions, with properties that can be studied with lattice simulations.\nDespite the recent surge of interest in $Sp(2N)$ gauge theories as a candidate\nfor models of physics beyond the standard model, studies of these theories at\nfinite temperature are still very limited. In this contribution we will present\npreliminary results of an ongoing numerical investigation of the thermodynamic\nproperties of the deconfinement phase transition in $Sp(4)$ Yang-Mills theory,\nusing the linear logarithmic relaxation algorithm. This method enables us to\nobtain a highly accurate determination of the density of states, allowing for a\nprecise reconstruction of thermodynamic observables. In particular, it gives\naccess to otherwise difficult to determine quantities such as the free energy\nof the system, even along metastable and unstable branches, hence providing an\nadditional direct observable to study the dynamics of the phase transition.",
        "positive": "Absence of sign problem in two-dimensional N=(2,2) super Yang-Mills on\n  lattice: We show that N=(2,2) SU(N) super Yang-Mills theory on lattice does not have\nsign problem in the continuum limit, that is, under the phase-quenched\nsimulation phase of the determinant localizes to 1 and hence the phase-quench\napproximation becomes exact. Among several formulations, we study models by\nCohen-Kaplan-Katz-Unsal (CKKU) and by Sugino. We confirm that the sign problem\nis absent in both models and that they converge to the identical continuum\nlimit without fine tuning. We provide a simple explanation why previous works\nby other authors, which claim an existence of the sign problem, do not capture\nthe continuum physics."
    },
    {
        "anchor": "Neutron Electric Dipole Moment from Beyond the Standard Model: We discuss the phenomenology of neutron Electric Dipole Moment from the\nStandard Model and beyond, and identify the matrix elements most necessary to\nconnect the current and forthcoming experiments with phenomenology. We then\ndescribe lattice techniques for calculating these matrix elements",
        "positive": "Numerical study of chiral symmetry breaking in non-Abelian gauge theory\n  with background magnetic field: We investigate the effect of a uniform background magnetic field on the\nchiral symmetry breaking in SU(2) Yang-Mills theory on the lattice. We observe\nthat the chiral condensate grows linearly with the field strength B up to\n\\sqrt{e B} = 3 GeV as predicted by chiral perturbation theory for full QCD. As\nthe temperature increases the coefficient in front of the linear term gets\nsmaller. In the magnetic field near-zero eigenmodes of the Dirac operator tend\nto have more regular structure with larger (compared to zero-field case)\nHausdorff dimensionality. We suggest that the delocalization of near-zero\neigenmodes plays a crucial role in the enhancement of the chiral symmetry\nbreaking."
    },
    {
        "anchor": "The diagonal and off-diagonal quark number susceptibility of high\n  temperature and finite density QCD: We study the quark number susceptibility of the hot quark-gluon plasma at\nzero and non-zero quark number density, using lattice Monte Carlo simulations\nof an effective theory of QCD, electrostatic QCD (EQCD). Analytic continuation\nis used to obtain results at non-zero quark chemical potential. We measure both\nflavor singlet (diagonal) and non-singlet (off-diagonal) quark number\nsusceptibilities. The diagonal susceptibility approaches the perturbative\nresult above 20T_c, but below that temperature we observe significant\ndeviations. The results agree well with 4d lattice data down to temperatures\n2T_c. The off-diagonal susceptibility is more prone to statistical and\nsystematic errors, but the results are consistent with perturbation theory\nalready at 10T_c.",
        "positive": "A Lattice Computation of the First Moment of the Kaon's Distribution\n  Amplitude: We present a lattice computation of the first moment of the kaon's\nleading-twist distribution amplitude. The results were computed using ensembles\nwith 2+1 dynamical flavours with the domain wall fermion action and Iwasaki\ngauge action from the RBC and UKQCD joint dataset. The first moment is non-zero\nbecause of SU(3)-breaking effects, and we find that we are able to measure\nthese effects very clearly. We observe the expected chiral behaviour and\nfinally obtain <\\xi>(2GeV) = 3/5*a_K^1(2GeV) = 0.032(3), which agrees very well\nwith results obtained using sum-rules, but with a significantly smaller error."
    },
    {
        "anchor": "Low temperature condensation and scattering data: We study $\\phi^4$ lattice field theory at finite chemical potential $\\mu$ in\ntwo and four dimensions, using a worldline representation that overcomes the\ncomplex action problem. We compute the particle number at very low temperature\nas a function of $\\mu$ and determine the first three condensation thresholds,\nwhere the system condenses 1, 2 and 3 particles. The corresponding critical\nvalues of the chemical potential can be related to the 1-, 2- and 3-particle\nenergies of the system, and we check this relation with a direct spectroscopy\ndetermination of the $n$-particle energies from $2n$-point functions. We\nanalyze the thresholds as a function of the spatial size of the system and use\nthe known finite volume results for the $n$-particle energies to relate the\nthresholds to scattering data. For four dimensions we determine the scattering\nlength from the 2-particle threshold, while in two dimensions the full\nscattering phase shift can be determined. In both cases the scattering data\ncomputed from the 2-particle threshold already allow one to determine the\n3-particle energy. In both, two and four dimensions we find very good agreement\nof this ''prediction'' with direct determinations of the 3-particle energy from\neither the thresholds or the 6-point functions. The results show that low\ntemperature condensation is indeed governed by scattering data.",
        "positive": "Nucleon axial structure from lattice QCD: We present a new analysis method that allows one to understand and model\nexcited state contributions in observables that are dominated by a pion pole.\nWe apply this method to extract axial and (induced) pseudoscalar nucleon\nisovector form factors, which satisfy the constraints due to the partial\nconservation of the axial current up to expected discretization effects.\nEffective field theory predicts that the leading contribution to the (induced)\npseudoscalar form factor originates from an exchange of a virtual pion, and\nthus exhibits pion pole dominance. Using our new method, we can recover this\nbehavior directly from lattice data. The numerical analysis is based on a large\nset of ensembles generated by the CLS effort, including physical pion masses,\nlarge volumes (with up to $96^3 \\times 192$ sites and $L m_\\pi = 6.4$), and\nlattice spacings down to $0.039 \\, \\text{fm}$, which allows us to take all the\nrelevant limits. We find that some observables are much more sensitive to the\nchoice of parametrization of the form factors than others. On the one hand, the\n$z$-expansion leads to significantly smaller values for the axial dipole mass\nthan the dipole ansatz ($M_A^{\\text{$z$-exp}}=1.02(10) \\, \\text{GeV}$ versus\n$M_A^{\\text{dipole}} = 1.31(8) \\, \\text{GeV}$). On the other hand, we find that\nthe result for the induced pseudoscalar coupling at the muon capture point is\nalmost independent of the choice of parametrization ($g_P^{\\star \\\n\\text{$z$-exp}} = 8.68(45)$ and $g_P^{\\star \\ \\text{dipole}} = 8.30(24)$), and\nis in good agreement with both, chiral perturbation theory predictions and\nexperimental measurement via ordinary muon capture. We also determine the axial\ncoupling constant $g_A$."
    },
    {
        "anchor": "The dependence of overlap topological charge density on Wilson mass\n  parameter: In this paper, we analyze the dependence of the topological charge density\nfrom the overlap operator on the Wilson mass parameter in the overlap kernel by\nthe symmetric multi-probing source (SMP) method. We observe that the\nnon-trivial topological objects are removed as the Wilson mass is increased. A\ncomparison of topological charge density calculated by the SMP method using\nfermionic definition with that of gluonic definition by the Wilson flow method\nis shown. A matching procedure for these two methods is used. We find that\nthere is a best match for topological charge density between gluonic definition\nwith varied Wilson flow time and fermionic definition with different Wilson\nmass. By using the matching procedure, the proper flow time of Wilson flow in\nthe calculation of topological charge density can be estimated. As the lattice\nspacing $a$ decreases, the proper flow time also decreases, as expected.",
        "positive": "Abelian monopoles in finite temperature lattice gauge fields:\n  Classically perfect action, smoothing and various Abelian gauges: Using the renormalization group motivated smoothing technique, the large\nscale structure of lattice configurations at finite temperature is\ncharacterized in terms of Abelian monopoles identified in the maximally\nAbelian, the Laplacian Abelian, and the Polyakov gauge. Abundance and\nanisotropy of monopoles at deconfinement and gauge invariant properties like\nlocal non-Abelian action and topological density are studied. Monopoles are\npredominantly found in regions of large action and topological charge, rather\nindependent of the chosen gauge."
    },
    {
        "anchor": "Tensor network formulation for two-dimensional lattice $\\mathcal{N}=1$\n  Wess-Zumino model: Supersymmetric models with spontaneous supersymmetry breaking suffer from the\nnotorious sign problem in stochastic approaches. By contrast, the tensor\nnetwork approaches do not have such a problem since they are based on\ndeterministic procedures. In this work, we present a tensor network formulation\nof the two-dimensional lattice $\\mathcal{N}=1$ Wess-Zumino model while showing\nthat numerical results agree with the exact solutions for the free case.",
        "positive": "Mass anomalous dimension of SU(2) with Nf=8 using the spectral density\n  method: SU(2) with Nf=8 is believed to have an infrared conformal fixed point. We use\nthe spectral density method to evaluate the coupling constant dependence of the\nmass anomalous dimension for massless HEX smeared, clover improved Wilson\nfermions with Schr\\\"odinger functional boundary conditions."
    },
    {
        "anchor": "Center vortex model for the infrared sector of SU(3) Yang-Mills theory\n  -- baryonic potential: The baryonic potential in the framework of the SU(3) random vortex\nworld-surface model is evaluated for a variety of static color source\ngeometries. For comparison, carefully taking into consideration the string\ntension anisotropy engendered by the hypercubic lattice description, also the\nDelta and Y law predictions for the baryonic potential are given. Only the Y\nlaw predictions are consistent with the baryonic potentials measured.",
        "positive": "Non-perturbative renormalization of HQET and QCD: We discuss the necessity of non-perturbative renormalization in QCD and HQET\nand explain the general strategy for solving this problem. A few selected\ntopics are discussed in some detail, namely the importance of off-shell\nimprovement in the MOM-scheme on the lattice, recent progress in the\nimplementation of finite volume schemes and then particular emphasis is put on\nthe recent idea to carry out a non-perturbative renormalization of the Heavy\nQuark Effective Theory."
    },
    {
        "anchor": "Lattice Gauge Theory Sum Rule for the Shear Channel: An exact expression is derived for the $(\\omega,p)=0$ thermal correlator of\nshear stress in SU($N_c$) lattice gauge theory. I remove a logarithmic\ndivergence by taking a suitable linear combination of the shear correlator and\nthe correlator of the energy density. The operator product expansion shows that\nthe same linear combination has a finite limit when $\\omega\\to\\infty$. It\nfollows that the vacuum-subtracted shear spectral function vanishes at large\nfrequencies at least as fast as $\\alpha_s^2(\\omega)$ and obeys a sum rule. The\ntrace anomaly makes a potential contribution to the spectral sum rule which\nremains to be fully calculated, but which I estimate to be numerically small\nfor $T\\gtrsim 3T_c$. By contrast with the bulk channel, the shear channel\nspectral density is then overall enhanced as compared to the spectral density\nin vacuo.",
        "positive": "Non-perturbative renormalization of overlap quark bilinears on domain\n  wall fermion configurations: We present renormalization constants of overlap quark bilinear operators on\n2+1-flavor domain wall fermion configurations. Both overlap and domain wall\nfermions have chiral symmetry on the lattice. The scale independent\nrenormalization constant for the local axial vector current is computed using a\nWard Identity. The renormalization constants for the scalar, pseudoscalar and\nvector current are calculated in the RI-MOM scheme. Results in the MS-bar\nscheme are obtained by using perturbative conversion ratios. The analysis uses\nin total six ensembles with lattice sizes 24^3x64 and 32^3x64."
    },
    {
        "anchor": "Simulating nonequilibrium quantum fields with stochastic quantization\n  techniques: We present lattice simulations of nonequilibrium quantum fields in\nMinkowskian space-time. Starting from a non-thermal initial state, the\nreal-time quantum ensemble in 3+1 dimensions is constructed by a stochastic\nprocess in an additional (5th) ``Langevin-time''. For the example of a\nself-interacting scalar field we show how to resolve apparent unstable Langevin\ndynamics, and compare our quantum results with those obtained in classical\nfield theory. Such a direct simulation method is crucial for our understanding\nof collision experiments of heavy nuclei or other nonequilibrium phenomena in\nstrongly coupled quantum many-body systems.",
        "positive": "The Local Bosonic Algorithm applied to the massive Schwinger model: We investigate various variants of the Hermitean version of the Local Bosonic\nAlgorithm proposed by M. L\\\"uscher. The model used is two-dimensional Quantum\nElectrodynamics (QED) with two flavours of massive Wilson fermions. The\nsimplicity of the model allows high statistics simulations close to the chiral\nand continuum limit.\n  To find optimal CPU cost behaviour, we vary the approximation polynomial\nparameters $n$ and \\epsilon$ as well as the number of over-relaxation steps\nwithin each trajectory. We find flat behaviour around the optimum and a modest\ngain with respect to the Hybrid Monte Carlo algorithm for all variants.\n  On the technical side, we demonstrate that a noisy Metropolis acceptance step\nis possible also for the Hermitean variant. The numerical instabilities\nappearing in the evaluation Chebyshev polynomial are investigated. We propose a\nquantitative criterion for these instabilities and a reordering scheme of the\nroots reducing the problem.\n  The more physical problem of topological charge sectors and metastability is\naddressed. We find no plateau in the effective pion mass if metastabilities\nbecome too large."
    },
    {
        "anchor": "The Lattice Schwinger Model: Confinement, Anomalies, Chiral Fermions and\n  All That: In order to better understand what to expect from numerical CORE computations\nfor two-dimensional massless QED (the Schwinger model) we wish to obtain some\nanalytic control over the approach to the continuum limit for various choices\nof fermion derivative. To this end we study the Hamiltonian formulation of the\nlattice Schwinger model (i.e., the theory defined on the spatial lattice with\ncontinuous time) in $A_0=0$ gauge. We begin with a discussion of the solution\nof the Hamilton equations of motion in the continuum, we then parallel the\nderivation of the continuum solution within the lattice framework for a range\nof fermion derivatives. The equations of motion for the Fourier transform of\nthe lattice charge density operator show explicitly why it is a regulated\nversion of this operator which corresponds to the point-split operator of the\ncontinuum theory and the sense in which the regulated lattice operator can be\ntreated as a Bose field. The same formulas explicitly exhibit operators whose\nmatrix elements measure the lack of approach to the continuum physics. We show\nthat both chirality violating Wilson-type and chirality preserving SLAC-type\nderivatives correctly reproduce the continuum theory and show that there is a\nclear connection between the strong and weak coupling limits of a theory based\nupon a generalized SLAC-type derivative.",
        "positive": "Charm and strange quark masses and $f_{D_s}$ from overlap fermions: We use overlap fermions as valence quarks to calculate meson masses in a wide\nquark mass range on the $2+1$-flavor domain-wall fermion gauge configurations\ngenerated by the RBC and UKQCD Collaborations. The well-defined quark masses in\nthe overlap fermion formalism and the clear valence quark mass dependence of\nmeson masses observed from the calculation facilitate a direct derivation of\nphysical current quark masses through a global fit to the lattice data, which\nincorporates $O(a^2)$ and $O(m_c^4a^4)$ corrections, chiral extrapolation, and\nquark mass interpolation. Using the physical masses of $D_s$, $D_s^*$ and\n$J/\\psi$ as inputs, Sommer's scale parameter $r_0$ and the masses of charm\nquark and strange quark in the $\\overline{\\rm MS}$ scheme are determined to be\n$r_0=0.465(4)(9)$ fm, $m_c^{\\overline{\\rm MS}}(2\\,{\\rm GeV})=1.118(6)(24)$ GeV\n(or $m_c^{\\overline{\\rm MS}}(m_c)=1.304(5)(20)$ GeV), and $m_s^{\\overline{\\rm\nMS}}(2\\,{\\rm GeV})=0.101(3)(6)\\,{\\rm GeV}$, respectively. Furthermore, we\nobserve that the mass difference of the vector meson and the pseudoscalar meson\nwith the same valence quark content is proportional to the reciprocal of the\nsquare root of the valence quark masses. The hyperfine splitting of charmonium,\n$M_{J/\\psi}-M_{\\eta_c}$, is determined to be 119(2)(7) MeV, which is in good\nagreement with the experimental value. We also predict the decay constant of\n$D_s$ to be $f_{D_s}=254(2)(4)$ MeV. The masses of charmonium $P$-wave states\n$\\chi_{c0}, \\chi_{c1}$ and $h_c$ are also in good agreement with experiments."
    },
    {
        "anchor": "The hadronic running of the electroweak couplings from lattice QCD: The energy dependency (running) of the strength of electromagnetic\ninteractions $\\alpha$ plays an important role in precision tests of the\nStandard Model. The running of the former to the $Z$ pole is an input quantity\nfor global electroweak fits, while the running of the mixing angle is\nsusceptible to the effects of Beyond Standard Model physics, particularly at\nlow energies. We present a computation of the hadronic vacuum polarization\n(HVP) contribution to the running of these electroweak couplings at the\nnon-perturbative level in lattice QCD, in the space-like regime up to $Q^2$\nmomentum transfers of $7\\,\\mathrm{GeV}^2$. This quantity is also closely\nrelated to the HVP contribution to the muon $g-2$. We observe a tension of up\nto $3.5$ standard deviation between our lattice results for\n$\\Delta\\alpha^{(5)}_{\\mathrm{had}}(-Q^2)$ and estimates based on the $R$-ratio\nfor $Q^2$ in the $3$ to $7\\,\\mathrm{GeV}^2$ range. The tension is, however,\nstrongly diminished when translating our result to the $Z$ pole, by employing\nthe Euclidean split technique and perturbative QCD, which yields\n$\\Delta\\alpha^{(5)}_{\\mathrm{had}}(M_Z^2)=0.027\\,73(15)$. This value agrees\nwith results based on the $R$-ratio within the quoted uncertainties, and can be\nused as an alternative to the latter in global electroweak fits.",
        "positive": "Higher angular momentum states of bottomonium in lattice NRQCD: On a cubic lattice the zero-momentum meson states have one of 20 possible\nLambda^{PC} combinations where Lambda labels the irreducible representation of\nthe octahedral group. Each continuum bottomonium state with specific J^{PC}\nquantum numbers is contained within one or more of the lattice Lambda^{PC}\nstates. In this work, bottomonium quark-antiquark operators are constructed for\nall 20 lattice Lambda^{PC} combinations which allows many continuum high\nangular momentum states to be accessible as ground states of their associated\nlattice channels. From a dynamical simulation, realistic results are obtained\nfor S-, P-, D-, F- and G-wave bottomonium states."
    },
    {
        "anchor": "Recent progress in hadron structure from Lattice QCD: We review recent progress in hadron structure using lattice QCD simulations,\nwith main focus in the evaluation of nucleon quantities such as the axial and\ntensor charges, and the spin con- tent of the nucleon, using simulations at\npion masses close to the physical value. We highlight developments on the\nevaluation of the gluon moment, a new direct approach to compute quark parton\ndistributions functions on the lattice, as well as, the neutron electric dipole\nmoment. A discussion of the systematic uncertainties and the computation of the\ndisconnected contributions using dynamical simulations is also included.",
        "positive": "The locality of the fourth root of staggered fermion determinant in the\n  interacting case: The fourth root approximation in LQCD simulations with dynamical staggered\nfermions requires justification. We test its validity numerically in the\ninteracting theory in a renormalization group framework."
    },
    {
        "anchor": "Results on the disconnected contributions for hadron structure: We present results on the disconnected contributions to three point functions\nentering in studies of hadron structure. We use $N_F = 2+1+1$ twisted mass\nfermions and give a detailed description on the results of the nucleon\n{\\sigma}-terms, isoscalar axial charge and first moments of bare parton\ndistributions for a range of pions masses. In addition we give the\n{\\sigma}-terms and the computations are performed using QUDA code implemented\non GPUs.",
        "positive": "Finite-volume effects and the electromagnetic contributions to kaon and\n  pion masses: We report on the MILC Collaboration calculation of electromagnetic effects on\nlight pseudoscalar mesons. The simulations employ asqtad staggered dynamical\nquarks in QCD plus quenched photons, with lattice spacings varying from 0.12 to\n0.06 fm. Finite volume corrections for the MILC realization of lattice\nelectrodynamics have been calculated in chiral perturbation theory and applied\nto the lattice data. These corrections differ from those calculated by Hayakawa\nand Uno because our treatment of zero modes differs from theirs. Updated\nresults for the corrections to \"Dashen's theorem\" are presented."
    },
    {
        "anchor": "Pion form factor with chirally improved fermions: We present results for Monte Carlo calculations of the electromagnetic vector\nand scalar form factors of the pion in a quenched simulation. We work at a\nlattice spacing of 0.15 fm and use two lattice volumes up to a spatial size of\n2.4 fm. The pion form factors in the space-like region are determined for pion\nmasses down to 340 MeV.",
        "positive": "Yet another way to obtain low temperature expansions for discrete spin\n  systems: I present a modification of the shadow-lattice technique, which allows one to\nderive low temperature series for discrete spin models to high orders. Results\nare given for the 3-d Ising model up to 64 excited bonds, for the 4-d Ising\nmodel up to 96 excited bonds and the 3-d Potts model up to 56 excited bonds."
    },
    {
        "anchor": "Searching for chiral logs in the static-light decay constant: Using the clover fermion action in unquenched QCD with pion masses as low as\n420 MeV, we look for evidence for chiral logs in the static-light decay\nconstant. There is some evidence for a chiral log term, if the original static\ntheory of Eichten and Hill is used. However, the more precise data from the\nstatic action of the ALPHA collaboration do not show any evidence for\nnon-linear dependence of the static-light decay constant on the light quark\nmass. We make some comments on the connection between chiral perturbation\ntheory for decay constants of the pion and static-light meson.",
        "positive": "Nucleon Generalized Parton Distributions from Full Lattice QCD: We present a comprehensive study of the lowest moments of nucleon generalized\nparton distributions in N_f=2+1 lattice QCD using domain wall valence quarks\nand improved staggered sea quarks. Our investigation includes helicity\ndependent and independent generalized parton distributions for pion masses as\nlow as 350 MeV and volumes as large as (3.5 fm)^3, for a lattice spacing of\n0.124 fm. We use perturbative renormalization at one-loop level with an\nimprovement based on the non-perturbative renormalization factor for the axial\nvector current, and only connected diagrams are included in the isosinglet\nchannel."
    },
    {
        "anchor": "Singlet Free Energies of a Static Quark-Antiquark Pair: We study the singlet part of the free energy of a static quark anti-quark\npair at finite temperature in three flavor QCD with degenerate quark masses\nusing $N_{\\tau}=4$ and 6 lattices with Asqtad staggered fermion action. We look\nat thermodynamics of the system around phase transition and study its scaling\nwith lattice spacing and quark masses.",
        "positive": "Non-perturbative renormalization factors of bilinear quark operators for\n  Kogut-Susskind fermions and light quark masses in quenched QCD: Light quark masses are computed for Kogut-Susskind fermions by evaluating\nnon-perturbatively the renormalization factor for bilinear quark operators.\nCalculations are carried out in the quenched approximation at \\beta=6.0, 6.2,\nand 6.4. For the average up and down quark mass we find $m_{\\bar MS}(2 GeV)=\n4.15(27) MeV$ in the continuum limit, which is significantly larger than\n$3.51(20) MeV$ ($q^*=1/a$) or $3.40(21) MeV$ ($q^*=\\pi/a$) obtained with the\none-loop perturbative renormalization factor."
    },
    {
        "anchor": "An Effective Model for Crumpling in Two Dimensions?: We investigate the crumpling transition for a dynamically triangulated random\nsurface embedded in two dimensions using an effective model in which the\ndisordering effect of the $X$ variables on the correlations of the normals is\nreplaced by a long-range ``antiferromagnetic'' term. We compare the results\nfrom a Monte Carlo simulation with those obtained for the standard action which\nretains the $X$'s and discuss the nature of the phase transition.",
        "positive": "Gauge invariant discretization of Poincare quantum gravity: In this paper we suggest gauge invariant discretization of Poincare quantum\ngravity. We generalize Regge calculus to the case of Riemann-Cartan space. The\nbasic element of the constructed discretization is piecewize linear\nRiemann-Cartan space with flat pieces of hypercubic form. We consider the model\nwith squared curvature action and calculate the correspondent lattice action.\nWe construct local measure over the dynamical variables of the lattice model."
    },
    {
        "anchor": "Matrix elements of the complete set of \u0394B = 2 and \u0394C = 2\n  operators in heavy meson chiral perturbation theory: Using heavy meson chiral perturbation theory, we consider the light\nquark-mass and spatial volume dependence of the matrix elements of \\Delta B=2\nand \\Delta C=2 four-quark operators relevant for\nB^{0}_{(s)}{-}\\bar{B}^{0}_{(s)} and D^{0}{-}\\bar{D}^{0} mixing, and the B_{s}\nmeson width difference. Our results for these matrix elements are obtained in\nthe N_{f}=2+1 partially quenched theory, which becomes full QCD in the limit\nwhere sea and valence quark masses become equal. They can be used in\nextrapolation of lattice calculations of these matrix elements to the physical\nlight quark masses and to infinite volume. An important conclusion of this\npaper is that the chiral extrapolations for matrix elements of heavy-light\nmeson mixing beyond the Standard Model, and those relevant for the B_s width\ndifference are more complicated than that for the Standard Model mixing matrix\nelements.",
        "positive": "Large-charge conformal dimensions at the $O(N)$ Wilson-Fisher fixed\n  point: Recent work using a large-charge expansion for the $O(N)$ Wilson-Fisher\nconformal field theory has shown that the anomalous dimensions of large-charge\noperators can be expressed in terms of a few low-energy constants (LECs) of a\nlarge-charge effective field theory (EFT). By performing lattice Monte Carlo\ncomputations at the $O(N)$ Wilson-Fisher fixed point, we compute the anomalous\ndimensions of large-charge operators up to $N=8$ and charge $Q=10$, and extract\nthe leading and subleading LECs of the $O(N)$ large-charge EFT. To alleviate\nthe signal-to-noise ratio problem present in the large-charge sector of\nconventional lattice formulations of the $O(N)$ theory, we employ a recently\ndeveloped qubit formulation of the $O(N)$ nonlinear sigma models with a worm\nalgorithm. This enables us to test the validity of the large-charge expansion\nand the recent large-$N$ predictions for the coefficients of the large-charge\nEFT."
    },
    {
        "anchor": "Staggered Chiral Perturbation Theory for Heavy-Light Mesons: We incorporate heavy-light mesons into staggered chiral perturbation theory,\nworking to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first\nnon-trivial order in the chiral expansion, staggered taste violations affect\nthe chiral logarithms for heavy-light quantities only through the light meson\npropagators in loops. There are also new analytic contributions coming from\nadditional terms in the Lagrangian involving heavy-light and light mesons.\nUsing this heavy-light staggered chiral perturbation theory, we perform the\none-loop calculation of the B (or D) meson leptonic decay constant in the\npartially quenched and full QCD cases. In our treatment, we assume the validity\nboth of the \"fourth root trick\" to reduce four staggered tastes to one, and of\nthe prescription to represent this trick in the chiral theory by insertions of\nfactors of 1/4 for each sea quark loop.",
        "positive": "Conditional Normalizing flow for Monte Carlo sampling in lattice scalar\n  field theory: The cost of Monte Carlo sampling of lattice configurations is very high in\nthe critical region of lattice field theory due to the high correlation between\nthe samples. This paper suggests a Conditional Normalizing Flow (C-NF) model\nfor sampling lattice configurations in the critical region to solve the problem\nof critical slowing down. We train the C-NF model using samples generated by\nHybrid Monte Carlo (HMC) in non-critical regions with low simulation costs. The\ntrained C-NF model is employed in the critical region to build a Markov chain\nof lattice samples with negligible autocorrelation. The C-NF model is used for\nboth interpolation and extrapolation to the critical region of lattice theory.\nOur proposed method is assessed using the 1+1-dimensional scalar $\\phi^4$\ntheory. This approach enables the construction of lattice ensembles for many\nparameter values in the critical region, which reduces simulation costs by\navoiding the critical slowing down."
    },
    {
        "anchor": "Extracting the $\u03b7^\\prime$ meson mass from gluonic correlators in\n  lattice QCD: Calculation of the eta-prime meson mass is a notoriously difficult problem,\nas it requires evaluation of the disconnected diagram which is costly and\nnoisy. In this work, we use a gluonic operator to extract the eta-prime state\nafter smearing the link variables through the Wilson flow. With this choice,\none can avoid a large cancellation of pion contribution between the connected\nand disconnected diagrams. We obtain the eta-prime meson mass on lattices with\nthree different lattice spacings and two physical volumes, which allow us to\nestimate its continuum and large volume limits.",
        "positive": "Non-Gaussian fixed point in four-dimensional pure compact U(1) gauge\n  theory on the lattice: The line of phase transitions, separating the confinement and the Coulomb\nphases in the four-dimensional pure compact U(1) gauge theory with extended\nWilson action, is reconsidered. We present new numerical evidence that a part\nof this line, including the original Wilson action, is of second order. By\nmeans of a high precision simulation on homogeneous lattices on a sphere we\nfind that along this line the scaling behavior is determined by one fixed point\nwith distinctly non-Gaussian critical exponent nu = 0.365(8). This makes the\nexistence of a nontrivial and nonasymptotically free four-dimensional pure U(1)\ngauge theory in the continuum very probable. The universality and duality\narguments suggest that this conclusion holds also for the monopole loop gas,\nfor the noncompact abelian Higgs model at large negative squared bare mass, and\nfor the corresponding effective string theory."
    },
    {
        "anchor": "Exploratory Study of the 3-Gluon Vertex on the Lattice: We define and evaluate on the lattice the amputated 3-gluon vertex function\nin momentum space.\n  We give numerical results for $16^3 \\times 40$ and $24^3 \\times 40$ quenched\nlattices at $\\beta=6.0$.\n  A good numerical signal is obtained, at the price of enforcing the\ngauge-fixing condition with high accuracy.\n  By comparing results from two different lattice volumes, we try to\ninvestigate the crucial issue of finite volume effects.\n  We also outline a method for the lattice evaluation of the QCD running\ncoupling constant as defined from the 3-gluon vertex, while being aware that a\nrealistic calculation will require larger $\\beta$ values and very high\nstatistics.",
        "positive": "HMC algorithm for two-flavour lattice QCD: Schwarz-preconditioning with\n  a one-dimensional domain decomposition: We study a variant of the Schwarz-preconditioned HMC algorithm. In contrast\nto the original proposal of L\\\"uscher, we apply the domain decomposition in one\nlattice direction only. This is sufficient to reduce the condition number of\nthe fermion matrix restricted to the domains compared with the full fermion\nmatrix. For the same linear extension of the domain, less links reside on the\nboundaries of the domains. Therefore it becomes e.g. practical to iterate the\ndecomposition. We perform numerical tests for two degenerate flavours of Wilson\nfermions. The standard Wilson gauge action at $\\beta=5.6$ is used. The\nperformance of our implementation is compared with other recent studies using\nvarious types of preconditioning."
    },
    {
        "anchor": "Ginsparg-Wilson Fermions in Odd Dimensions: The Ginsparg-Wilson relation, if written in a suitable form, can be used as a\ncondition for lattice Dirac operators of massless fermions also in odd\ndimensions. The fermion action with such a Dirac operator is invariant under a\ngeneralized parity transformation, which reduces to the ordinary parity\ntransformation in the (naive) continuum limit. The fermion measure, however,\ntransforms non-trivially under the generalized parity transformation, and hence\nthe parity anomaly arises solely from the fermion measure. The analogy to the\nlattice construction of chiral gauge theories in even dimensions is clarified\nby considering a dimensional reduction. We also propose a natural definition of\na lattice Chern-Simons term, which is consistent with odd dimensional\nGinsparg-Wilson fermions.",
        "positive": "Quenched Heavy-Light Decay Constants: We present results for heavy-light decay constants, using both propagating\nquarks and the static approximation, in O(a)-improved, quenched lattice QCD. At\nbeta=6.2 on a 24^3x48 lattice we find f_D=185 +4-3(stat)+42-7(syst) MeV,\nf_B=160 +6-6 +53-19 MeV, f_{D_s}/f_D=1.18 +2-2 and f_{B_s}/f_B=1.22 +4-3, in\ngood agreement with earlier studies. From the static theory we obtain\nf_B^stat=253 +16-15 +105-14 MeV. We also present results from a simulation at\nbeta=6.0 on a 16^3x48 lattice, which are consistent with those at beta=6.2. In\norder to study the effects of improvement, we present a direct comparison of\nthe results using both the Wilson and the improved action at beta=6.0."
    },
    {
        "anchor": "NNLO Unquenched Calculation of the b Quark Mass: By combining the first unquenched lattice computation of the B-meson binding\nenergy and the two-loop contribution to the lattice HQET residual mass, we\ndetermine the (\\bar{{MS}}) (b)-quark mass, (\\bar{m}_{b}(\\bar{m}_{b})). The\ninclusion of the two-loop corrections is essential to extract\n(\\bar{m}_{b}(\\bar{m}_{b})) with a precision of ({\\cal\nO}(\\Lambda^{2}_{QCD}/m_{b})), which is the uncertainty due to the renormalon\nsingularities in the perturbative series of the residual mass. Our best\nestimate is (\\bar{m}_{b}(\\bar{m}_{b}) = (4.26 \\pm 0.09) {\\rm GeV}), where we\nhave combined the different errors in quadrature. A detailed discussion of the\nsystematic errors contributing to the final number is presented. Our results\nhave been obtained on a sample of (60) lattices of size (24^{3}\\times 40) at\n(\\beta =5.6), using the Wilson action for light quarks and the lattice HQET for\nthe (b) quark, at two values of the sea quark masses. The quark propagators\nhave been computed using the unquenched links generated by the T(\\chi)L\nCollaboration.",
        "positive": "Isospin-breaking corrections to light leptonic decays in lattice QCD+QED\n  at the physical point: We report on the physical-point RBC/UKQCD calculation of the leading\nisospin-breaking corrections to light-meson leptonic decays. This is highly\nrelevant for future precision tests in the flavour physics sector, in\nparticular the first-row unitarity of the Cabibbo-Kobayashi-Maskawa matrix\ncontaining the elements $V_{us}$ and $V_{ud}$. The simulations were performed\nusing Domain-Wall fermions for $2+1$ flavours, and with isospin-breaking\neffects included perturbatively in the path integral through order $\\alpha$ and\n$(m_u - m_d)/\\Lambda _{\\mathrm{QCD}}$. We use QED$_{\\mathrm{L}}$ for the\ninclusion of electromagnetism, and discuss here the non-locality of this\nprescription which has significant impact on the infinite-volume extrapolation."
    },
    {
        "anchor": "Static quark correlators and quarkonium properties at non-zero\n  temperature: We discuss different static quark correlators, including Wilson loops in 2+1\nflavor QCD at non-zero temperature and their relation to in-medium quarkonium\nproperties. We present lattice results on static correlation functions obtained\nwith highly improved staggered fermion action and their implications for\npotential models.",
        "positive": "How to control nonlinear effects in Binder cumulants: We point out that ignoring nonlinear effects in finite size scaling may lead\nto errors in estimates of the critical temperature and Binder cumulants. We\nshow that the order of magnitude of these effects can be estimated from data at\nrelatively small volume. Using this estimate, we propose to use linear fits in\nincreasingly small temperature regions as the volume is increased (rather than\nusing a fixed temperature interval). The choice of the exact coefficient of\nproportionality can be optimized and reveals interesting crossing patterns\namong estimates. We show that the new procedure works very well for Dyson's\nhierarchical model. We discuss applications of the method for 3 dimensional\nspin models and finite temperature lattice gauge theories and comment on the\nnonlinear effects for existing calculations."
    },
    {
        "anchor": "Density-density correlators using all-to-all propagators: We present a study of gauge invariant density-density correlators.\nDensity-density correlators probe hadron wave functions and thus can be used to\nstudy hadron deformation. Their zero momentum projection requires the\ncomputation of all-to-all propagators, which are evaluated with the standard\nstochastic technique, the dilution method and the stochastic sequential\ntechnique. We compare the results to a previous analysis that did not employ\nthe zero momentum projection.",
        "positive": "Two-loop additive mass renormalization with clover fermions and Symanzik\n  improved gluons: We calculate the critical value of the hopping parameter, $\\kappa_c$, in\nLattice QCD, up to two loops in perturbation theory. We employ the\nSheikholeslami-Wohlert (clover) improved action for fermions and the Symanzik\nimproved gluon action with 4- and 6-link loops.\n  The quantity which we study is a typical case of a vacuum expectation value\nresulting in an additive renormalization; as such, it is characterized by a\npower (linear) divergence in the lattice spacing, and its calculation lies at\nthe limits of applicability of perturbation theory.\n  Our results are polynomial in $c_{SW}$ (clover parameter) and cover a wide\nrange of values for the Symanzik coefficients $c_i$. The dependence on the\nnumber of colors N and the number of fermion flavors $N_f$ is shown explicitly.\nIn order to compare our results to non perturbative evaluations of $\\kappa_c$\ncoming from Monte Carlo simulations, we employ an improved perturbation theory\nmethod for improved actions."
    },
    {
        "anchor": "Continuum limit of string formation in 3-d SU(2) LGT: We study the continuum limit of the string-like behaviour of flux tubes\nformed between static quarks and anti-quarks in three dimensional SU(2) lattice\ngauge theory. We compare our simulation data with the predictions of both\neffective string models as well as perturbation theory. On the string side we\nobtain clear evidence for convergence of data to predictions of Nambu-Goto\ntheory. We comment on the scales at which the static potential starts departing\nfrom one loop perturbation theory and then again being well described by\neffective string theories. We also estimate the leading corrections to the\none-loop perturbative potential as well as the Nambu-Goto effective string. In\nthe intermediate regions we find that a modified Lennard-Jones type potential\ngives surprisingly good fits.",
        "positive": "Quenched lattice calculation of semileptonic heavy-light meson form\n  factors: We calculate, in the continuum limit of quenched lattice QCD, the matrix\nelements of the heavy-heavy vector current between heavy-light pseudoscalar\nmeson states. We present the form factors for different values of the initial\nand final meson masses at finite momentum transfer. In particular, we calculate\nthe non-perturbative correction to the differential decay rate of the process B\n--> D l nu including the case of a non-vanishing lepton mass."
    },
    {
        "anchor": "Heavy-dense QCD at fixed baryon number without a sign problem: QCD at fixed baryon number can be formulated in terms of transfer matrices\nexplicitly defined in the canonical sectors. In the heavy-dense limit, the\nfermionic contributions to the canonical partition functions in terms of\nPolyakov loops and quark occupation numbers turn out to be completely\nfactorized in space. At low temperatures and infinitely strong coupling the\nsign problem is reduced by orders of magnitude for any baryon number as\ncompared to the corresponding grand-canonical ensemble. In the canonical\nformulation it is straighforward to integrate out the Polyakov loops in the\nfermionic weights yielding the partition function as a sum of only baryon\noccupation numbers in which the sign problem is absent. Using an effective form\nof the gauge action valid for small values of the gauge coupling, the same can\nbe achieved away from the strong coupling limit in terms of quark occupation\nnumbers and fluxes which couple the quarks with each other. The emerging\nclusters suggest the construction of algorithms which circumvent the sign\nproblem in the heavy-dense limit including the full gauge action for any value\nof the gauge coupling.",
        "positive": "Bosonic Partition Functions: The behavior of quenched Dirac spectra of two-dimensional lattice QCD is\nconsistent with spontaneous chiral symmetry breaking which is forbidden\naccording to the Coleman-Mermin-Wagner theorem. One possible resolution of this\nparadox is that, because of the bosonic determinant in the partially quenched\npartition function, the conditions of this theorem are violated allowing for\nspontaneous symmetry breaking in two dimensions or less. This goes back to work\nby Niedermaier and Seiler on nonamenable symmetries of the hyperbolic spin\nchain and earlier work by two of the auhtors on bosonic partition functions at\nnonzero chemical potential. In this talk we discuss chiral symmetry breaking\nfor the bosonic partition function of QCD at nonzero isospin chemical potential\nand a bosonic random matrix theory at imaginary chemical potential and compare\nthe results with the fermionic counterpart. In both cases the chiral symmetry\ngroup of the bosonic partition function is noncompact."
    },
    {
        "anchor": "A study of the quark-gluon vertex: We present the first results from a study of the quark--gluon vertex function\nin the Landau gauge. The results are obtained for quenched QCD with an\nO(a)-improved Wilson fermion action, at beta=6.0. We discuss plans for further\nstudy, including extraction of a renormalised QCD coupling from the momentum\ndependence of the vertex.",
        "positive": "Short Strings and Gluon Propagator in the Infrared Region: We discuss how infrared region influence on short distance physics via new\nobject, called ``short string''. This object exists in confining theories and\nviolates the operator product expansion. Most analytical results are obtained\nfor the dual Abelian Higgs theory, while phenomenological arguments are given\nfor QCD."
    },
    {
        "anchor": "Short-distance charmonium correlator on the lattice with M\u00f6bius\n  domain-wall fermion and a determination of charm quark mass: We calculate charmonium correlators on the lattice with 2+1-flavors of sea\nquarks and charm valence quark both described by the M\\\"obius domain-wall\nfermion. Temporal moments of the correlators are calculated and matched to\nperturbative QCD formulae to extract the charm quark mass $m_c(\\mu)$ and strong\ncoupling constant $\\alpha_s(\\mu)$. Lattice data at three lattice spacings,\n0.044, 0.055, and 0.080~fm, are extrapolated to the continuum limit. The\ncorrelators in the vector channel are confirmed to be consistent with the\nexperimental data for $e^+e^-\\to c\\bar{c}$, while the pseudo-scalar channel is\nused to extract $m_c(\\mu)$ and $\\alpha_s(\\mu)$. We obtain $m_\\mathrm{c}(3\n\\mathrm{\\ GeV})$ = 1.003(10)~GeV and\n$\\alpha_s^{\\bar{\\mathrm{MS}}(4)}(3\\mathrm{\\ GeV})$ = 0.253(13). Dominant source\nof the error is the truncation of perturbative expansion at $\\alpha_s^3$.",
        "positive": "An Anderson-like model of the QCD chiral transition: We study the problems of chiral symmetry breaking and eigenmode localisation\nin finite-temperature QCD by looking at the lattice Dirac operator as a random\nHamiltonian. We recast the staggered Dirac operator into an unconventional\nthree-dimensional Anderson Hamiltonian (\"Dirac-Anderson Hamiltonian\") carrying\ninternal degrees of freedom, with disorder provided by the fluctuations of the\ngauge links. In this framework, we identify the features relevant to chiral\nsymmetry restoration and localisation of the low-lying Dirac eigenmodes in the\nordering of the local Polyakov lines, and in the related correlation between\nspatial links across time slices, thus tying the two phenomena to the\ndeconfinement transition. We then build a toy model based on QCD and on the\nDirac-Anderson approach, replacing the Polyakov lines with spin variables and\nsimplifying the dynamics of the spatial gauge links, but preserving the\nabove-mentioned relevant dynamical features. Our toy model successfully\nreproduces the main features of the QCD spectrum and of the Dirac eigenmodes\nconcerning chiral symmetry breaking and localisation, both in the ordered\n(deconfined) and disordered (confined) phases. Moreover, it allows us to study\nseparately the roles played in the two phenomena by the diagonal and the\noff-diagonal terms of the Dirac-Anderson Hamiltonian. Our results support our\nexpectation that chiral symmetry restoration and localisation of the low modes\nare closely related, and that both are triggered by the deconfinement\ntransition."
    },
    {
        "anchor": "Delta expansion and Wilson fermion in the Gross-Neveu model:\n  Compatibility with linear divergence and continuum limit from inverse-mass\n  expansion: We apply the $\\delta$-expansion to the Gross-Neveu model in the large $N$\nlimit with Wilson fermion and investigate dynamical mass generation from\ninverse-mass expansion. The dimensionless mass $M$ defined via the effective\npotential is employed as the expansion parameter of the bare coupling constant\n$\\beta$ which is partially renormalized by the subtraction of linear\ndivergence. We show that $\\delta$-expansion of the $1/M$ series of $\\beta$ is\ncompatible with the mass renormalization. After the confirmation of the\ncontinuum scaling of the bare coupling without fermion doubling, we attempt to\nestimate dynamical mass in the continuum limit and obtain the results\nconverging to the exact value for values of Wilson parameter $r\\in (0.8,1.0)$.",
        "positive": "QCD in Extreme Environments: I review present challenges that QCD in extreme environments presents to\nlattice gauge theory. Recent data and impressions from RHIC are emphasized.\nPhysical pictures of heavy ion wavefunctions, collisions and the generation of\nthe Quark Gluon Plasma are discussed, with an eye toward engaging the lattice\nand its numerical methods in more interaction with the experimental and\nphenomenological developments. Controversial, but stimulating scenarios which\ncan be confirmed or dismissed by lattice methods are covered. In the second\nhalf of the talk, several promising developments presented at the conference\nLattice 2002 are reviewed."
    },
    {
        "anchor": "Chiral symmetry breaking in nearly conformal gauge theories: We present new results on chiral symmetry breaking in nearly conformal gauge\ntheories with fermions in the fundamental representation of the SU(3) color\ngauge group. The number of fermion flavors is varied in an extended range below\nthe conformal window with chiral symmetry breaking ($\\chi{\\rm SB}$) for all\nflavors between $N_f=4$ and $N_f=12$. To identify $\\chi{\\rm SB}$ we apply\nseveral methods which include, within the framework of chiral perturbation\ntheory, the analysis of the Goldstone spectrum in the p-regime and the spectrum\nof the fermion Dirac operator with eigenvalue distributions of random matrix\ntheory in the $\\eps$-regime. Chiral condensate enhancement is observed with\nincreasing $N_f$ when the electroweak symmetry breaking scale $F$ is held fixed\nin technicolor language. Important finite-volume consistency checks from the\ntheoretical understanding of the $SU(N_f)$ rotator spectrum of the\n$\\delta$-regime are discussed. We also consider these gauge theories at\n$N_f=16$ inside the conformal window. The importance of understanding finite\nvolume, zero momentum gauge field dynamics inside the conformal window is\npointed out. Staggered lattice fermions with supressed taste breaking are used\nthroughout the simulations.",
        "positive": "Decorrelation of the topological charge in tempered simulations of full\n  QCD: The improvement of simulations of QCD with dynamical Wilson fermions by\ncombining the Hybrid Monte Carlo algorithm with parallel tempering is studied.\nAs an indicator for decorrelation the topological charge is used."
    },
    {
        "anchor": "High performance Beowulf computer for lattice QCD: We describe the construction of a high performance parallel computer composed\nof PC components, as well as the performance test in lattice QCD.",
        "positive": "Study of Lattice Correlation Functions at Small Times using the QCD Sum\n  Rules Continuum Model: In this paper we study the work of Leinweber by applying the Continuum Model\nof QCD Sum Rules (QCDSR) to the analysis of (quenched) lattice correlation\nfunctions. We expand upon his work in several areas: we study meson states as\nwell as baryons; we analyse data from several lattice spacings; and we include\ndata from the Sheikholeslami-Wohlert (clover) improved action. We find that the\nQCDSR Continuum Model Ansatz can reproduce the data, but only for non-physical\nvalues of its parameters. This leads us to reject it as a model for hadronic\ncorrelation functions.\n  We study the non-relativistic quark model and conclude that it predicts\nessentially the same form for the correlation function as the QCDSR Continuum\nModel approach. Furthermore, because it doesn't have the Continuum Model's\nrestrictions on the parameters, the non-relativistic quark model can be viewed\nas a successful Ansatz.\n  As well as studying the validity or otherwise of the QCDSR Continuum Model\napproach, this paper defines 4-parameter fitting functions that can be used to\nfit lattice data even for a time window close to the source. These functions\nare shown to be an improvement over 2-exponential fits especially in the case\nof mesons. We encourage the application of this approach to situations where\nthe conventional fitting procedures are problematic due to poor ground state\ndominance."
    },
    {
        "anchor": "Towards the determination of the 3-dimensional structure of the proton\n  using lattice QCD simulations: State-of-the-art lattice QCD simulations enable the evaluation of nucleon\nform factors and Mellin moments with controlled systematics, yielding results\nwith unprecedented accuracy. At the same time, new theoretical approaches are\nallowing the direct computation of nucleon generalized parton distributions. We\nreview recent lattice QCD results on these quantities that are paving the way\nfor extracting a wealth of information on the 3-dimensional structure of the\nnucleon.",
        "positive": "Infrared Features of the Landau Gauge QCD: The infrared features of Landau gauge QCD are studied by the lattice\nsimulation of $\\beta=6.0, 16^4, 24^4, 32^4$ and $\\beta=6.4, 32^4, 48^4$. We\nadopt two definitions of the gauge field; 1) $U-$linear 2) $\\log U$ and\nmeasured the gluon propagator and ghost propagator. Infrared singularity of the\ngluon propagator is less than that of tree level result but the gluon\npropagator at 0 momentum remains finite. The infrared singularity of ghost\npropagator is stronger than the tree level. The QCD running coupling measured\nby using the gluon propagator and the ghost propagator has a maximum\n$\\alpha_s(p)\\simeq 1$ at around $p=0.5GeV$ and decreases as $p$ approaches 0.\nThe data are analyzed in use of formula of the principle of minimal\nsensitivity(PMS), the effective charge method and the contour-improved\nperturbation method, which suggest necessity of the resummation of perturbation\nseries in the infrared region together with existence of the infrared fixed\npoint. Kugo-Ojima parameter saturates at about -0.8 in contrast to the\ntheoretically expected value -1."
    },
    {
        "anchor": "Low-lying Dirac operator eigenvalues, lattice effects and random matrix\n  theory: Recently, random matrix theory predictions for the distribution of low-lying\nDirac operator eigenvalues have been extended to include lattice effects for\nboth staggered and Wilson fermions. We computed low-lying eigenvalues for the\nHermitian Wilson-Dirac operator and for improved staggered fermions on several\nquenched ensembles with size $\\approx 1.5$ fm. Comparisons to the expectations\nfrom RMT with lattice effects included are made. Wilson RMT describes our\nWilson data nicely. For improved staggered fermions we find strong indications\nthat taste breaking effects on the low-lying spectrum disappear in the\ncontinuum limit, as expected from staggered RMT.",
        "positive": "Eight spectra of very excited flux tubes in $SU(3)$ gauge theory: We compute the spectra of flux tubes formed between a static quark antiquark\npair up to a significant number of excitations and for eight symmetries of the\nflux tubes, up to $\\Delta_u$, using pure $SU(3)$ gauge lattice QCD in $3+1$\ndimensions. To accomplish this goal, we use a large set of appropriate\noperators, an anisotropic tadpole improved action, smearing techniques, and\nsolve a generalized eigenvalue problem. Moreover, we compare our results with\nthe Nambu-Goto string model to evaluate possible tensions which could be a\nsignal for novel phenomena."
    },
    {
        "anchor": "$|V_{ub}|$ from $B\\to\u03c0\\ell\u03bd$ decays and (2+1)-flavor lattice QCD: We present a lattice-QCD calculation of the $B\\to\\pi\\ell\\nu$ semileptonic\nform factors and a new determination of the CKM matrix element $|V_{ub}|$. We\nuse the MILC asqtad 2+1-flavor lattice configurations at four lattice spacings\nand light-quark masses down to 1/20 of the physical strange-quark mass. We\nextrapolate the lattice form factors to the continuum using staggered chiral\nperturbation theory in the hard-pion and SU(2) limits. We employ a\nmodel-independent $z$ parameterization to extrapolate our lattice form factors\nfrom large-recoil momentum to the full kinematic range. We introduce a new\nfunctional method to propagate information from the chiral-continuum\nextrapolation to the $z$ expansion. We present our results together with a\ncomplete systematic error budget, including a covariance matrix to enable the\ncombination of our form factors with other lattice-QCD and experimental\nresults. To obtain $|V_{ub}|$, we simultaneously fit the experimental data for\nthe $B\\to\\pi\\ell\\nu$ differential decay rate obtained by the BaBar and Belle\ncollaborations together with our lattice form-factor results. We find\n$|V_{ub}|=(3.72\\pm 0.16)\\times 10^{-3}$ where the error is from the combined\nfit to lattice plus experiments and includes all sources of uncertainty. Our\nform-factor results bring the QCD error on $|V_{ub}|$ to the same level as the\nexperimental error. We also provide results for the $B\\to\\pi\\ell\\nu$ vector and\nscalar form factors obtained from the combined lattice and experiment fit,\nwhich are more precisely-determined than from our lattice-QCD calculation\nalone. These results can be used in other phenomenological applications and to\ntest other approaches to QCD.",
        "positive": "Spectral Density on the Lattice: Spectral density in the pseudoscalar and vector channels is extracted from\nthe SU(2) lattice quenched data. It is shown to consist of three sharp poles\nwithin the energy range accessible on the lattice."
    },
    {
        "anchor": "An anisotropic hybrid non-perturbative formulation for 4D N = 2\n  supersymmetric Yang-Mills theories: We provide a simple non-perturbative formulation for non-commutative\nfour-dimensional N = 2 supersymmetric Yang-Mills theories. The formulation is\nconstructed by a combination of deconstruction (orbifold projection), momentum\ncut-off and matrix model techniques. We also propose a moduli fixing term that\npreserves lattice supersymmetry on the deconstruction formulation. Although the\nanalogous formulation for four-dimensional N = 2 supersymmetric Yang-Mills\ntheories is proposed also in Nucl.Phys.B857(2012), our action is simpler and\nbetter suited for computer simulations. Moreover, not only for the\nnon-commutative theories, our formulation has a potential to be a\nnon-perturbative tool also for the commutative four-dimensional N = 2\nsupersymmetric Yang-Mills theories.",
        "positive": "Searching for a continuum 4D field theory arising from a 5D non-abelian\n  gauge theory: The anisotropic 5D SU(2) Yang-Mills model has been widely investigated on the\nlattice during the last decade. In the case where all dimensions are large in\nsize, it was previously claimed that there is a new phase in the phase diagram,\ncalled the Layer phase. In this phase, the gauge fields would be localized on\n4D layers. Previous works claim that the phase transition to the Layer phase is\nof second order, which would allow a continuum limit to be taken. We present\nthe extension of the previous work to large lattices, for which we found a\nfirst order phase transition. This leaves the scenario that this 5D theory can\nbe dimensionally reduced to a continuum 4D field theory, doubtful."
    },
    {
        "anchor": "The spin structure of the Lambda hyperon in quenched lattice QCD: It has been suggested to use the production of Lambda hyperons for\ninvestigating the nucleon spin structure. The viability of this idea depends\ncrucially on the spin structure of the Lambda. Using nonperturbatively O(a)\nimproved Wilson fermions in the quenched approximation we have studied matrix\nelements of two-quark operators in the Lambda. We present results for the axial\nvector current, which give us the contributions of the u, d, and s quarks to\nthe Lambda spin.",
        "positive": "Strong isospin violation and chiral logarithms in the baryon spectrum: We present a precise lattice QCD calculation of the contribution to the\nneutron-proton mass splitting arising from strong isospin breaking,\n$m_n-m_p|_{QCD}=2.32\\pm0.17$ MeV. We also determine $m_{\\Xi^-} -\nm_{\\Xi^0}|_{QCD} = 5.44\\pm0.31$ MeV. The calculation is performed at three\nvalues of the pion mass, with several values of the quark mass splitting and\nmultiple lattice volumes, but only a single lattice spacing and an estimate of\ndiscretization errors. The calculations are performed on the anisotropic\nclover-Wilson ensembles generated by the Hadron Spectrum Collaboration. The\nomega-baryon mass is used to set the scale $a_t^{-1}=6111\\pm127$ MeV, while the\nkaon masses are used to determine the value of the light-quark mass spitting.\nThe nucleon mass splitting is then determined as a function of the pion mass.\nWe observe, for the first time, conclusive evidence for non-analytic light\nquark mass dependence in lattice QCD calculations of the baryon spectrum. When\nleft as a free parameter, the fits prefer a nucleon axial coupling of\n$g_A=1.24(56)$. To highlight the presence of this chiral logarithm in the\nnucleon mass splitting, we also compute the isospin splitting in the\ncascade-baryon system which is less sensitive to chiral dynamics. Finally, we\nupdate the best lattice QCD determination of the CP-odd pion-nucleon coupling\nthat would arise from a non-zero QCD theta-term, $\\bar{g}_0 / (\\sqrt{2}f_\\pi) =\n(14.7\\pm1.8\\pm1.4) \\cdot 10^{-3} \\bar{\\theta}$.\n  The original lattice QCD correlation functions, analysis results and\nextrapolated quantities are packaged in HDF5 files made publicly available\nincluding a simple Python script to access the numerical results, construct\neffective mass plots along with our analysis results, and perform the\nextrapolations of various quantities determined in this work."
    },
    {
        "anchor": "Resurgence and fractional instanton of the SU($3$) gauge theory in weak\n  coupling regime: According to recent studies on resurgence scenario of quantum systems, some\ntopological objects with fractional charges play an important role to see the\nresurgence structure. In this talk, we report a numerical evidence of the\nfractional-instantons of the SU($3$) gauge theory. The fractional-instanton\nappears in a weak coupling regime, if the theory is regularized by an infrared\n(IR) cutoff via the $1$-form twisted boundary conditions. The Polyakov loop is\nalso measured to investigate the center symmetry and confinement. The\nfractional-instanton corresponds to a solution linking two of degenerate\n$\\mathbb{Z}_3$-broken vacua in the deconfinement phase. This talk is based on\nthe paper[1].",
        "positive": "Gauge-fixed Lattice QCD and the dispersion relation of Wilson fermions: We show that, when investigating Wilson-fermions correlation functions on the\nlattice, one is bound to encounter major difficulties in defining their\ndispersion relation, even at tree level. The problem is indeed quite general\nand, although we stumbled upon it while studying Coulomb-gauge applications, it\nalso affects gauge fixed studies in covariant gauges, including their most\npopular version, Landau gauge. In this paper we will discuss a solution to this\nproblems based on a redefinition of the kinematic momentum of the fermion."
    },
    {
        "anchor": "Non-Perturbative Determination of $c_{\\rm SW}$ in Three-flavor Dynamical\n  QCD: We present a fully non-perturbative determination of the $O(a)$ improvement\ncoefficient $c_{\\rm SW}$ in three-flavor dynamical QCD for the RG improved as\nwell as the plaquette gauge actions, using the Schr\\\"odinger functional scheme.\nResults are compared with one-loop estimates at weak gauge coupling.",
        "positive": "Fixed-point pure gauge action using $ b= \\sqrt{3} $ RGT: We present a status report on the construction of the classical perfect\naction using the $ b=\\sqrt{3} $ renormalization group transformation (RGT). We\ninvestigate finite volume corrections and map the locality of the fixed-point\naction by tuning the RGT parameter, $\\kappa$. We compare results with the\nprevious calculation for b=2 RGT."
    },
    {
        "anchor": "An update of Euclidean windows of the hadronic vacuum polarization: We compute the standard Euclidean window of the hadronic vacuum polarization\nusing multiple independent blinded analyses. We improve the continuum and\ninfinite-volume extrapolations of the dominant quark-connected light-quark\nisospin-symmetric contribution and address additional sub-leading systematic\neffects from sea-charm quarks and residual chiral-symmetry breaking from first\nprinciples. We find $a_\\mu^{\\rm W} = 235.56(65)(50) \\times 10^{-10}$, which is\nin $3.8\\sigma$ tension with the recently published dispersive result of\nColangelo et al., $a_\\mu^{\\rm W} = 229.4(1.4) \\times 10^{-10}$, and in\nagreement with other recent lattice determinations. We also provide a result\nfor the standard short-distance window. The results reported here are unchanged\ncompared to our presentation at the Edinburgh workshop of the g-2 Theory\nInitiative in 2022.",
        "positive": "Can the nearly conformal sextet gauge model hide the Higgs impostor?: New results are reported from large scale lattice simulations of a frequently\ndiscussed strongly interacting gauge theory with a fermion flavor doublet in\nthe two-index symmetric (sextet) representation of the SU(3) color gauge group.\nWe find that the chiral condensate and the mass spectrum of the sextet model\nare consistent with chiral symmetry breaking in the limit of vanishing fermion\nmass. In contrast, sextet fermion mass deformations of spectral properties are\nnot consistent with leading conformal scaling behavior near the critical\nsurface of a conformal theory. A recent paper could not resolve the conformal\nfixed point of the gauge coupling from the slowly walking scenario of a very\nsmall nearly vanishing \\beta-function (DeGrand:2012yq). It is argued that\noverall consistency with our new results is resolved if the sextet model is\nclose to the conformal window, staying outside with a very small non-vanishing\n\\beta-function. The model would exhibit then the simplest composite Higgs\nmechanism leaving open the possibility of a light scalar state with quantum\nnumbers of the Higgs impostor. It would emerge as the pseudo-Goldstone dilaton\nstate from spontaneous symmetry breaking of scale invariance. We will argue\nthat even without association with the dilaton, the scalar Higgs-like state can\nbe light very close to the conformal window. A new Higgs project of sextet\nlattice simulations is outlined to resolve these important questions."
    },
    {
        "anchor": "Study of SU(2) gauge theories with multiple Higgs fields in different\n  representations: We study two different SU(2) gauge-scalar theories in 3 and 4 spacetime\ndimensions. Firstly, we focus on the 3 dimensional SU(2) theory with multiple\nHiggs fields in the adjoint representation, that can be mapped to cuprate\nsystems in condensed matter physics which host a rich phase diagram including\nhigh-Tc superconductivity. It has been proposed that the theory with 4 adjoint\nHiggs fields can be used to explain the physics of hole-doped cuprates for a\nwide range of parameters. We show exploratory results on the phase diagram of\nthe theory.\n  On the other hand, we are interested in the 4 dimensional theory with 2 sets\nof fundamental scalar (Higgs) fields, which is relevant to the 2 Higgs Doublet\nModel (2HDM), a proposed extension to the Standard Model of particle physics.\nThe goal is to understand the particle spectrum of the theory at zero\ntemperature and the electroweak phase transition at finite temperature. We\npresent exploratory results on scale setting and the multi-parameter phase\ndiagram of this theory.",
        "positive": "The RANLUX generator: resonances in a random walk test: Using a recently proposed directed random walk test, we systematically\ninvestigate the popular random number generator RANLUX developed by Luescher\nand implemented by James. We confirm the good quality of this generator with\nthe recommended luxury level. At a smaller luxury level (for instance equal to\n1) resonances are observed in the random walk test. We also find that the\nlagged Fibonacci and Subtract-with-Carry recipes exhibit similar failures in\nthe random walk test. A revised analysis of the corresponding dynamical systems\nleads to the observation of resonances in the eigenvalues of Jacobi matrix."
    },
    {
        "anchor": "Hamiltonian Lattice QCD near the Light Cone: We give a status report of our work on light cone Hamiltonian lattice QCD. We\nhave derived an effective Hamiltonian $H_{eff}$ which is only quadratic in the\nmomenta and therefore can be simulated by standard methods. For this\nHamiltonian we determine variationally an approximate ground state wave\nfunctional in the light cone limit.",
        "positive": "Lattice quantum gravity - an update: We advocate lattice methods as the tool of choice to constructively define a\nbackground-independent theory of Lorentzian quantum gravity and explore its\nphysical properties in the Planckian regime. The formulation that arguably has\nmost furthered our understanding of quantum gravity (and of various pitfalls\npresent in the nonperturbative sector) uses dynamical triangulations to\nregularize the nonperturbative path integral over geometries. Its Lorentzian\nversion in terms of Causal Dynamical Triangulations (CDT) - in addition to\nhaving a definite quantum signature on short scales - has been shown to\nreproduce important features of the classical theory on large scales. This\narticle recaps the most important developments in CDT of the last few years for\nthe physically relevant case of four spacetime dimensions, and describes its\nstatus quo at present."
    },
    {
        "anchor": "Neutron-antineutron oscillations from lattice QCD: Fundamental symmetry tests of baryon number violation in low-energy\nexperiments can probe beyond the Standard Model (BSM) explanations of the\nmatter-antimatter asymmetry of the universe. Neutron-antineutron oscillations\nare predicted to be a signature of many baryogenesis mechanisms involving\nlow-scale baryon number violation. This work presents first-principles\ncalculations of neutron-antineutron matrix elements needed to accurately\nconnect measurements of the neutron-antineutron oscillation rate to constraints\non $|\\Delta B|=2$ baryon number violation in BSM theories. Several important\nsystematic uncertainties are controlled by using a state-of-the-art lattice\ngauge field ensemble with physical quark masses and approximate chiral\nsymmetry, performing nonperturbative renormalization with perturbative matching\nto the $\\overline{\\text{MS}}$ scheme, and studying excited state effects in\ntwo-state fits. Phenomenological implications are highlighted by comparing\nexpected bounds from proposed neutron-antineutron oscillation experiments to\npredictions of a specific model of post-sphaleron baryogenesis. Quantum\nchromodynamics is found to predict at least an order of magnitude more events\nin neutron-antineutron oscillation experiments than previous estimates based on\nthe \"MIT bag model\" for fixed BSM parameters. Lattice artifacts and other\nsystematic uncertainties that are not controlled in this pioneering calculation\nare not expected to significantly change this conclusion.",
        "positive": "The Nielsen-Ninomiya ``No-Go'' Theorem is False: The Nielsen-Ninomiya no-go theorem asserts that chiral Weyl~(``neutrino'')\nfields cannot exist on lattices. However, the actual mathematical arguments\nadvanced in the theorem fail to make that case. The theorem leaves the problem\nof lattice neutrinos completely open; it identifies no obstacle which would\nprevent us from discretizing chiral theories.\n  (INFORMAL ABSTRACT: Have you too, like every second person in the field, been\nciting the Nielsen-Ninomiya theorem but have not read or analyzed it? Then,\nthis paper will wake you up. Reading it is a prerequisite to doing any good\nwork in chiral lattice physics.)"
    },
    {
        "anchor": "A numerical investigation of orientifold planar equivalence for quenched\n  mesons: We measure on the lattice the quenched pseudoscalar and vector meson masses\nat a fixed value of the lattice spacing for SU(N) gauge theory with fermions in\nthe adjoint, in the symmetric and in the antisymmetric representations of the\ngauge group. Simulations are performed for N=3,4,6 in all those\nrepresentations, with the addition of N=2 for the adjoint representation. We\nillustrate a strategy for separating the even from the odd-power contributions\nin 1/N in the masses. Using this technique, we extrapolate the vector mass to\nthe large-N limit in the chiral region and show that at N = infty this mass is\nthe same within errors in all the three representations, as predicted by\norientifold planar equivalence. Possible implications of our investigation for\nstudying orientifold planar equivalence in the dynamical case are discussed.",
        "positive": "Nature of Roberge-Weiss transition end points for heavy quarks in\n  $N_f=2$ lattice QCD with Wilson fermions: The phase structure of QCD with imaginary chemical potential provides\ninformation on the phase diagram of QCD with real chemical potential. With\nimaginary chemical potential $i\\mu_I=i\\pi T$, previous studies show that the\nRoberge-Weiss (RW) transition end points are triple points at both large and\nsmall quark masses, and second order transition points at intermediate quark\nmasses. The triple and second order end points are separated by two tricritical\nones. We present simulations with $ N_f=2 $ Wilson fermions to investigate the\nnature of RW transition end points. The simulations are carried out at 8 values\nof the hopping parameter $\\kappa$ ranging from 0.020 to 0.140 on different\nlattice volumes. The Binder cumulant, susceptibility and reweighted\ndistribution of the imaginary part of Polyakov loop are employed to determine\nthe nature of RW transition end points. The simulations show that the two\ntricritical points are within the range $0.070-0.080$ and $0.120-0.140$,\nrespectively."
    },
    {
        "anchor": "Chirality Correlation within Dirac Eigenvectors from Domain Wall\n  Fermions: In the dilute instanton gas model of the QCD vacuum, one expects a strong\nspatial correlation between chirality and the maxima of the Dirac eigenvectors\nwith small eigenvalues. Following Horvath, {\\it et al.} we examine this\nquestion using lattice gauge theory within the quenched approximation. We\nextend the work of those authors by using weaker coupling, $\\beta=6.0$, larger\nlattices, $16^4$, and an improved fermion formulation, domain wall fermions. In\ncontrast with this earlier work, we find a striking correlation between the\nmagnitude of the chirality density, $|\\psi^\\dagger(x)\\gamma^5\\psi(x)|$, and the\nnormal density, $\\psi^\\dagger(x)\\psi(x)$, for the low-lying Dirac eigenvectors.",
        "positive": "Quenched Hadron Spectroscopy with Improved Actions: A variety of different combinations of improved gluon and fermion actions is\ntested for quenched hadron spectroscopy"
    },
    {
        "anchor": "The spectrum of qubitized QCD: glueballs in a $S(1080)$ gauge theory: Quantum simulations of QCD require digitization of the infinite-dimensional\ngluon field. Schemes for doing this with the minimum amount of qubits are\ndesirable. We present a practical digitization for $SU(3)$ gauge theories via\nits discrete subgroup $S(1080)$. Using a modified action that allows classical\nsimulations down to $a\\approx 0.08$ fm, the low-lying glueball spectrum is\ncomputed with percent-level precision at multiple lattice spacings and shown to\nextrapolate to the continuum limit $SU(3)$ results. This suggests that this\ndigitization scheme is sufficient for precision quantum simulations of QCD.",
        "positive": "The Strong Coupling Constant from the Lattice 3-Gluon Vertex: We compute the QCD running coupling on the lattice as defined from the\n3-gluon vertex. We present the results of an exploratory study at $\\beta=6.0$\non a $16^4$ lattice, which show that for momenta larger than 2 \\Gev, the\ncoupling runs according to the 2-loop asymptotic formula, allowing a precise\ndetermination of the $\\Lambda$ parameter. Our renormalization procedure\ncorresponds to a momentum subtraction scheme in the continuum and, most\nremarkably, one does not need lattice perturbation theory to match the results\nto MSbar scheme. We obtain $\\alpha^{\\MSB}(M_Z) = 0.115 \\pm 0.003 \\pm 0.008$."
    },
    {
        "anchor": "Twisted mass lattice computation of charmed mesons with focus on\n  $D^{\\ast \\ast}$: We present results of a 2+1+1 flavor twisted mass lattice QCD computation of\nthe spectrum of $D$ mesons and $D_s$ mesons and of charmonium. Particular focus\nis put on the positive parity $D$ states (so-called $D^{\\ast \\ast}$ mesons)\nwith quantum numbers $J^P = 0^+$, $1^+$ and $2^+$. Besides computing their\nmasses we are also separating and classifying the two $J^P = 1^+$ states\naccording to the angular momentum/spin of their light degrees of freedom (light\nquarks and gluons) $j =1/2, 3/2$.",
        "positive": "Chiral corrections to the axial charges of the octet baryons from\n  quenched QCD: We calculate one-loop correction to the axial charges of the octet baryons\nusing quenched chiral perturbation theory, in order to understand chiral\nbehavior of the axial charges in quenched approximation to quantum\nchromodynamics (QCD). In contrast to regular behavior of the full QCD chiral\nperturbation theory result, $c_0+c_{l2}m_\\pi^2\\,\\ln{m_\\pi^2}+\\cdots$, we find\nthat the quenched chiral perturbation theory result,\n$c_0^Q+(c_{l0}^Q+c_{l2}^Qm_\\pi^2)\\ln{m_\\pi^2}+c_2^Q m_\\pi^2+\\cdots$, is\nsingular in the chiral limit."
    },
    {
        "anchor": "Phase Quenched Lattice QCD at Finite Density and Temperature: We simulate 3-flavour lattice QCD at finite quark-number chemical potential\nmu in the phase-quenched approximation, close to the finite temperature\ntransition. Working close to the critical quark mass, we find no evidence for\nthe expected critical endpoint at small mu. We are performing further\nsimulations aimed at calculating the equation-of-state of this theory outside\nof the superfluid domain, where its phase structure is expected to mimic the\nfull theory.",
        "positive": "A strategy to compute the b-quark mass with non-perturbative accuracy: We describe a strategy for a non-perturbative computation of the b-quark mass\nto leading order in 1/m in the Heavy Quark Effective Theory (HQET). The\napproach avoids the perturbative subtraction of power law divergencies, and the\ncontinuum limit may be taken. First numerical results in the quenched\napproximation demonstrate the potential of the method with a preliminary result\nm_b(4GeV)=4.56(2)(7) GeV. In principle, the idea may also be applied to the\nmatching of composite operators or the computation of 1/m corrections in HQET."
    },
    {
        "anchor": "Strong Interactions for the LHC: Dynamical electroweak symmetry breaking (DEWSB) has been a viable option for\nthe completion of the standard model for over thirty years. Precision\nelectroweak studies indicate that the new strong interactions that break EW\nsymmetry cannot be a scaled-up copy of QCD. Building viable models of DEWSB is\ndifficult without a detailed understanding of such non-QCD gauge theories which\nstill confine and break chiral symmetry. We review past difficulties of\nstudying these theories using lattice methods and describe recent progress,\nfocusing on the role of approximate infrared conformal symmetry.",
        "positive": "How Self-Dual is QCD?: Vacuum characteristics quantifying dynamical tendency toward self-duality in\ngauge theories could be used to judge the relevance of classical solutions or\nthe viability of classically motivated vacuum models. Here we decompose the\nfield strength of equilibrium gauge configurations into self-dual and\nanti-self-dual parts, and apply absolute X-distribution method to the resulting\npolarization dynamics in order to construct such characteristics. Using lattice\nregularization and focusing on pure-glue SU(3) gauge theory at zero\ntemperature, we find evidence for positive but very small dynamical tendency\nfor self-duality of vacuum in the continuum limit."
    },
    {
        "anchor": "Phase Transition in Lattice Surface Systems with Gonihedric Action: We prove the existence of an ordered low temperature phase in a model of\nsoft-self-avoiding closed random surfaces on a cubic lattice by a suitable\nextension of Peierls contour method. The statistical weight of each surface\nconfiguration depends only on the mean extrinsic curvature and on an\ninteraction term arising when two surfaces touch each other along some contour.\nThe model was introduced by F.J. Wegner and G.K. Savvidy as a lattice version\nof the gonihedric string, which is an action for triangulated random surfaces.",
        "positive": "Schwinger model simulations with dynamical overlap fermions: We present simulation results for the 2-flavour Schwinger model with\ndynamical overlap fermions. In particular we apply the overlap hypercube\noperator at seven light fermion masses. In each case we collect sizable\nstatistics in the topological sectors 0 and 1. Since the chiral condensate\nSigma vanishes in the chiral limit, we observe densities for the microscopic\nDirac spectrum, which have not been addressed yet by Random Matrix Theory\n(RMT). Nevertheless, by confronting the averages of the lowest eigenvalues in\ndifferent topological sectors with chiral RMT in unitary ensemble we obtain --\nfor the very light fermion masses -- values for Sigma that follow closely the\nanalytical predictions in the continuum."
    },
    {
        "anchor": "D-branes and Topological Charge in QCD: The recently observed long-range coherent structure of topological charge\nfluctuations in QCD is compared with theoretical expectations based on the\nAdS/CFT brane construction of nonsupersymmetric gauge theory by Witten. Similar\nobservations of coherent topologicalcharge structure in 2D $CP^{N-1}$ sigma\nmodels are interpreted in terms of Wilson lines representing world lines of\nscreened electric charges. The analogy between 2D U(1) and 4D Yang-Mills theory\nleads to the interpretation of the observed coherent sheets of topological\ncharge in QCD as screened ``Wilson bags'' first suggested by Luscher. The\nduality between the Wilson bag surface and a wrapped 6-brane in IIA string\ntheory is discussed. The complete screening of the force between bag surfaces\nfor integer values of the bag charge $\\theta/2\\pi$ corresponds to the\nobservation by Polchinski that the net force between d-branes from closed\nstring exchange vanishes for quantized values of Ramond-Ramond charge.",
        "positive": "QCD String formation and the Casimir Energy: Three distinct scales are identified in the excitation spectrum of the gluon\nfield around a static quark-antiquark pair as the color source separation R is\nvaried. The spectrum, with string-like excitations on the largest length scales\nof 2-3 fm, provides clues in its rich fine structure for developing an\neffective bosonic string description. New results are reported from the\nthree-dimensional Z(2) and SU(2) gauge models, providing further insight into\nthe mechanism of bosonic string formation. The precocious onset of string-like\nbehavior in the Casimir energy of the static quark-antiquark ground state is\nobserved below R=1 fm where most of the string eigenmodes do not exist and the\nfew stable excitations above the ground state are displaced. We find no firm\ntheoretical foundation for the widely held view of discovering string formation\nfrom high precision ground state properties below the 1 fm scale."
    },
    {
        "anchor": "Evaluation of Israel-Stewart parameters in lattice gauge theory: Navier-Stokes equations are known as hydrodynamic equations which take\naccount of effects of dissipations. There are, however, problems in the\nrelativistic Navier-Stokes equations, i.e. the equations violate causality.\nIsrael-Stewart equations, which evade the problems of Navier-Stokes equations\nby introducing new parameters, such as the relaxation times, have recently been\nused in describing the space-time evolution of the quark-gluon plasma produced\nin high energy heavy ion collisions. The viscosities and the relaxation times\nare related to each other by imposing entropy constraints on the system.\nAccording to Boltzmann-Einstein principle, the probability distribution of the\nfluctuation in the energy-momentum tensor is related to the entropy of the\nsystem. Applying this principle to the entropy in Israel-Stewart theory, one\ncan obtain the ratios of the viscosities to the relaxation times. We evaluate\nthe ratios of the viscosities to the relaxation times in SU(3) lattice gauge\ntheory.",
        "positive": "Evidence for a First Order, Finite Temperature Phase Transition in 8\n  Flavor QCD: As part of our ongoing investigations of QCD with many flavors of quarks,\nhere we report on studies of the finite temperature phase transition for\neight-flavor QCD with the DBW2 gauge action and na\\\"ive staggered fermions. We\nfind a clear first order phase transition between the chirally asymmetric phase\nat zero temperature and the chirally symmetric phase at finite temperature,\nsignaled by a two-state signal for $\\langle\\bar{\\psi}\\psi\\rangle$ at a non-zero\ntemperature. We see this signal at a gauge coupling of $\\beta=0.54$, where, to\nset the scale, the zero temperature value for $f_\\pi$, in the chiral limit, is\n0.06661(92). This strong, first-order signal is seen for two different values\nof the quark mass, $m_q=0.007$ and 0.0195, at $N_\\tau=8$ and 6 respectively.\nUsing $f_\\pi(m_q)$ as the scale, the critical temperature is measured to be\n$T_c/f_\\pi=1.638(93)$ at $m_\\pi/f_\\pi=3.329(30)$ for $m_q=0.007$, and\n$T_c/f_\\pi=1.779(27)$ at $m_\\pi/f_\\pi=4.093(15)$ for $m_q=0.0195$. At a weaker\ncoupling $\\beta=0.56$, where at zero temperature and in the chiral limit we\nfind $f_\\pi=0.0312(10)$, the first order signal becomes numerically invisible\nto us for the $N_\\tau \\leq 14$ lattices we have investigated so far."
    },
    {
        "anchor": "Quenched $B_K$-parameter from Osterwalder-Seiler tmQCD quarks and\n  mass-splitting discretization effects: We apply an Osterwalder-Seiler version of twisted mass QCD to a study of the\n$B_K$ parameter, in which three of the four quark fields making up the relevant\n$\\Delta S =2$ operator are maximally twisted with the same twist angle, while\nthe fourth one has a twist angle of opposite sign. It is known that this setup\nensures automatic improvement of the bare $K^0$-$\\overline K^0$ operator matrix\nelement and multiplicative renormalization of the $\\Delta S =2$ operator, at\nthe price of breaking the $K^0$-$\\overline K^0$ mass degeneracy by\ndiscretization effects. As a result, two dominant systematic errors of the $B_\nK$ determination with Wilson fermions are kept under control. With the Clover\nterm included in the fermion action, we perform a feasibility study and find,\nin the quenched approximation, a significant improvement of the scaling\nbehaviour of $B_K$, compared to earlier standard tmQCD determinations.\nMoreover, we study in detail the $K^0$-$\\overline K^0$ mass splitting that\ncharacterizes this approach and confirm that, in the presence of the Clover\nterm, it is greatly reduced in a maximally twisted theory.",
        "positive": "A determination of the mass gap in the O(n) sigma model: We calculate the finite volume mass gap $M(L)$ at 3-loop level in the\nnon-linear O($n$) $\\sigma$-model in two dimensions in small volumes. By\napplying the Monte Carlo measurements of the running coupling $\\bar\ng^2(L)=2nM(L)L/(n-1)$ by L\\\"uscher, Weisz and Wolff measured in units of the\nphysical mass gap $m$, the result is used to determine $m$ in units of the\n$\\Lambda$-parameter in the O(3) and O(4) models. Our determinations show good\nagreement with those by Hasenfratz, Maggiore and Niedermayer in both models. We\nnote that this manuscript has been revised in our paper hep-lat/9810025 by\nusing the corrected four-loop $\\beta$-function on the lattice."
    },
    {
        "anchor": "Precise determination of the strong coupling constant in Nf=2+1 lattice\n  QCD with the Schr\u00f6dinger functional scheme: We present an evaluation of the running coupling constant for Nf=2+1 QCD. The\nSchroedinger functional scheme is used as the intermediate scheme to carry out\nnon-perturbative running from the low energy region, where physical scale is\nintroduced, to deep in the high energy perturbative region, where conversion to\nthe MS-bar scheme is safely performed. Possible systematic errors due to the\nuse of perturbation theory occur only in the conversion from three-flavor to\nfour-flavor running coupling constant near the charm mass threshold, where\nhigher order terms beyond 5th order in the $\\beta$ function may not be\nnegligible.\n  For numerical simulations we adopted Iwasaki gauge action and\nnon-perturbatively improved Wilson fermion action with the clover term. Seven\nrenormalization scales are used to cover from low to high energy region and\nthree lattice spacings to take the continuum limit at each scale.\n  A physical scale is introduced from the previous Nf=2+1 simulation of the\nCP-PACS/JL-QCD collaboration, which covered the up-down quark mass range\nheavier than $m_\\pi\\sim 500$ MeV.",
        "positive": "Toward a resolution of the NN controversy: Lattice QCD calculations of two-nucleon interactions have been underway for\nabout a decade, but still haven't reached the pion mass regime necessary for\nmatching onto effective field theories and extrapolating to the physical point.\nFurthermore, results from different methods, including the use of the Luscher\nformalism with different types of operators, as well as the HALQCD potential\nmethod, do not agree even qualitatively at very heavy pion mass. We investigate\nthe role that different operators employed in the literature may play on the\nextraction of spectra for use within the Luscher method. We first explore\nexpectations from Effective Field Theory solved within a finite volume, for\nwhich the exact spectrum may be computed given different physical scenarios. We\nthen present preliminary lattice QCD results for two-nucleon spectra calculated\nusing different operators on a common lattice ensemble."
    },
    {
        "anchor": "A Quenched Study of SU(3) Glueballs at Finite Temperature: Thermal properties of glueballs in SU(3) Yang-Mills theory are investigated\nin a large temperature range from $0.3T_c$ to $1.9T_c$ on anisotropic lattices.\nThe glueball operators are optimized for the projection of the ground states by\nthe variational method with a smearing scheme. Their thermal correlators are\ncalculated in all 20 symmetry channels. It is found in all channels that the\npole masses $M_G$ of glueballs remain almost constant when the temperature is\napproaching the critical temperature $T_c$ from below, and start to reduce\ngradually with the temperature going above $T_c$. The correlators in the\n$0^{++}$, $0^{-+}$, and $2^{++}$ channels are also analyzed based on the\nBreit-Wigner $\\emph{Ansatz}$ by assuming a thermal width $\\Gamma$ to the pole\nmass $\\omega_0$ of each thermal glueball ground state. While the values of\n$\\omega_0$ are insensitive to $T$ in the whole temperature range, the thermal\nwidths $\\Gamma$ exhibit distinct behaviors at temperatures below and above\n$T_c$. The widths are very small (approximately few percent of $\\omega_0$ or\neven smaller) when $T<T_c$, but grow abruptly when $T>T_c$ and reach values of\nroughly $\\Gamma\\sim \\omega_0/2$ at $T\\approx 1.9T_c$.",
        "positive": "The Spectrum of tmLQCD with Quark and Link Smearing: The effect of using smeared sink operators on the hadron spectrum is studied\nfor quenched twisted mass lattice QCD with up, down, and strange quarks.\nGaussian smearing is used for quark fields, and stout link smearing for gauge\nfields. Smeared correlators are found to be dominated by the ground state with\na small contribution from excited states, leading to an improved determination\nof some ground state masses."
    },
    {
        "anchor": "Reanalysis of lattice QCD spectra leading to the $D_{s0}^*(2317)$ and\n  $D_{s1}^*(2460)$: We perform a reanalysis of the energy levels obtained in a recent lattice QCD\nsimulation, from where the existence of bound states of $KD$ and $KD^*$ are\ninduced and identified with the narrow $D_{s0}^*(2317)$ and $D_{s1}^*(2460)$\nresonances. The reanalysis is done in terms of an auxiliary potential,\nemploying a single-channel basis $KD^{(*)}$, and a two-channel basis $KD^{(*)},\n\\eta D_s^{(*)}$. By means of an extended L\\\"uscher method we determine poles of\nthe continuum $t$-matrix, bound by about 40 MeV with respect to the $KD$ and\n$KD^*$ thresholds, which we identify with the $D_{s0}^*(2317)$ and\n$D_{s1}^*(2460)$ resonances. Using a sum rule that reformulates Weinberg\ncompositeness condition we can determine that the state $D_{s0}^*(2317)$\ncontains a $KD$ component in an amount of about 70%, while the state\n$D_{s1}^*(2460)$ contains a similar amount of $KD^*$. We argue that the present\nlattice simulation results do not still allow us to determine which are the\nmissing channels in the bound state wave functions and we discuss the necessary\ninformation that can lead to answer this question.",
        "positive": "Topological Susceptibility in $N_f=2$ QCD at Finite Temperature: We study the topological charge in $N_f=2$ QCD at finite temperature using\nM\\\"obius domain-wall fermions. The susceptibility $\\chi_t$ of the topological\ncharge defined either by the index of overlap Dirac operator or a gluonic\noperator is investigated at several values of temperature $T\\ (>T_c)$ varying\nthe quark mass. A strong suppression of the susceptibility is observed below a\ncertain value of the quark mass. The relation with the restoration of $U_A(1)$\nis discussed."
    },
    {
        "anchor": "Hyperon couplings from $N_f = 2 + 1$ lattice QCD: We compute various (generalized) isovector charges of the octet baryons.\nThese include $g_A$, $g_T$ and $g_S$ as well as the unpolarized, polarized and\ntransversity parton distribution function (PDF) momentum fractions $\\langle\nx\\rangle_{u^+-d^+}$, $\\langle x\\rangle_{\\Delta u^--\\Delta d^-}$ and $\\langle\nx\\rangle_{\\delta u^+-\\delta ^+}$. The simulations are carried out on a subset\nof the (isospin symmetric) $N_f=2+1$ flavour Coordinated Lattice Simulations\n(CLS) gauge ensembles with lattice spacings ranging from $a\\approx 0.086\\,$fm\ndown to $a\\approx 0.050\\,$fm. First results on the breaking of flavour symmetry\nand the low energy constants $F$ and $D$ are presented. While SU(3) flavour\nsymmetry violations are found to be sizeable for $g_A=\\langle 1\\rangle_{\\Delta\nu^+-\\Delta d^+}$, these are quite small for $g_T=\\langle 1\\rangle_{\\delta\nu^--\\delta d^-}$ and $\\langle x\\rangle_{u^+-d^+}$.",
        "positive": "Direct Evaluation of the Quark Content of Nucleons from Lattice QCD at\n  the Physical Point: We evaluate the light, strange and charm scalar content of the nucleon using\none lattice QCD ensemble generated with two degenerate light quarks with mass\nfixed to their physical value. We use improved techniques to evaluate the\ndisconnected quark loops to sufficient accuracy to determine the strange and\ncharm nucleon $\\sigma$-terms. in addition to the light quark content\n$\\sigma_{\\pi N}$. We find $\\sigma_{\\pi N}$=$37.2(2.6)(^{4.7}_{2.9})$ MeV\n$\\sigma_{s}$=$41.1(8.2)(^{7.8}_{5.8})$ MeV and\n$\\sigma_c$=$79(21)(^{12}_{\\phantom{1}8})$ MeV, where the first error is\nstatistical and the second is the systematic error due to the determination of\nthe lattice spacing, the assessment of finite volume and residual excited state\neffects."
    },
    {
        "anchor": "Can One Study Heavy Meson Semileptonic Decays on Coarse Anisotropic\n  Lattices ?: Exploratory studies of heavy meson semileptonic decays on coarse lattices\nusing Symanzik improved glue, NRQCD heavy and D234 light quarks are discussed.\nComparisons are made between calculations on anisotropic and isotropic\nlattices. We find evidence that having an anisotropy helps in extracting better\nsignals at higher momenta.",
        "positive": "Gauge Corrections to Strong Coupling Lattice QCD on Anisotropic Lattices: Lattice QCD with staggered fermions can be formulated in dual variables to\naddress the finite baryon density sign problem. In the past we have performed\nsimulations in the strong coupling regime, including leading order gauge\ncorrections. In order to vary the temperature for fixed $\\beta$ it was\nnecessary to introduce a bare anisotropy. In this talk we will extend our work\nto include results from a non-perturbative determination of the physical\nanisotropy $a_\\sigma$/$a_\\tau = \\xi(\\gamma, \\beta)$, which is necessary to\nunambiguously locate the critical end point and the first order line of the\nchiral transition."
    },
    {
        "anchor": "Evolution of the Structure Factors in Pure SU(N) Lattice Gauge Theory\n  and Effective Spin Models: We consider model A dynamics for a quench from the disordered into the\nordered phase of SU(3) lattice gauge theory and the analogue 3d 3-state Potts\nmodel. For the gauge model this corresponds to a rapid heating from the\nconfined to the deconfined phase. The exponential growth factors of low-lying\nstructure function modes are numerically calculated. The linear theory of\nspinodal decomposition is used to determine the critical modes. This allows for\nthe Debye screening mass estimation in an effective phenomenological model. The\nquench leads to competing vacuum domains, which make the equilibration of the\nQCD vacuum after the heating non-trivial. The influence of such domains on the\ngluonic energy density is studied.",
        "positive": "The three-loop beta-function of SU(N) lattice gauge theories with\n  overlap fermions: We briefly report our calculation of the 2-loop coefficient of the coupling\nconstant renormalization function Z_g in lattice perturbation theory. The\nquantity under study is defined through g_0 = Z_g g, where g_0 (g) is the bare\n(renormalized) coupling constant. The 2-loop expression for Z_g can be directly\nrelated to the 3-loop bare beta-function beta_L(g_0).\n  Our calculation is performed using overlap fermions and Wilson gluons, and\nthe background field technique has been chosen for convenience. Our results\ndepend explicitly on the number of fermion flavors (N_f) and colors (N). Since\nthe dependence of Z_g on the overlap parameter rho cannot be extracted\nanalytically, we tabulate our results for different values of rho in the\nallowed range (0<rho<2), focusing on values which are being used most\nfrequently in simulations. Plots of the 1- and 2-loop results for Z_g versus\nrho exhibit a nontrivial dependence on the overlap parameter.\n  A longer write-up of this work may be found in 0709.4368."
    },
    {
        "anchor": "Nucleon isovector tensor charge from lattice QCD with physical light\n  quarks: We present preliminary results for the axial, scalar and tensor charges of\nthe nucleon measured in 2+1 flavor QCD with the physical light quarks\n($m_\\pi=135$ MeV). Our simulations are carried out with gauge configurations\ngenerated by the PACS Collaboration with the stout-smeared $O(a)$ improved\nWilson fermions and Iwasaki gauge action at a single lattice spacing of $0.085\\\n(\\mathrm{fm})$. There are two lattice ensembles of the PACS gauge\nconfigurations, which have physical lattice sizes over $(10\\ \\mathrm{fm})^4$\nand $(5\\ \\mathrm{fm})^4$, respectively. We compute the nucleon three-point\ncorrelation functions in the axial, scalar, and tensor channels. For the\nrenormalization, we use the Rome-Southampton method as the intermediate scheme\nin order to evaluate the renormalization constants for the scalar and tensor\ncurrents in fully nonperturbative manner. We then evaluate the renormalized\nvalues of the scalar and tensor charges ($g_S$ and $g_T$) in the $\\overline{\\rm\nMS}$ scheme at the renormalization scale of 2 GeV with a help of the continuum\nperturbation theory for the matching between two schemes. We compare our\npreliminary results of $g_S$ and $g_T$ with those of other collaboration\nresults.",
        "positive": "The Phase Diagram of Four Flavor SU(2) Lattice Gauge Theory at Nonzero\n  Chemical Potential and Temperature: SU(2) lattice gauge theory with four flavors of quarks is simulated at\nnonzero chemical potential $\\mu$ and temperature $T$ and the results are\ncompared to the predictions of Effective Lagrangians. Simulations on $16^4$\nlattices indicate that at zero $T$ the theory experiences a second order phase\ntransition to a diquark condensate state. Several methods of analysis,\nincluding equation of state fits suggested by Chiral Perturbation Theory,\nsuggest that mean-field scaling describes this critical point. Nonzero $T$ and\n$\\mu$ are studied on $12^3 \\times 6$ lattices. For low $T$, increasing $\\mu$\ntakes the system through a line of second order phase transitions to a diquark\ncondensed phase. Increasing $T$ at high $\\mu$, the system passes through a line\nof first order transitions from the diquark phase to the quark-gluon plasma\nphase. Metastability is found in the vicinity of the first order line. There is\na tricritical point along this line of transitions whose position is consistent\nwith theoretical predictions."
    },
    {
        "anchor": "Structure of hybrid static potential flux tubes in SU(2) lattice\n  Yang-Mills theory: We study the structure of the hybrid static potential flux tube in the\n$\\Pi_u$ sector in SU(2) lattice Yang-Mills theory. To this end, we compute the\nsquares of the chromoelectric and chromomagnetic field strengths in the\npresence of a static quark-antiquark pair. We show clear evidence that the\ngluon distribution is significantly different compared to that of the ordinary\nstatic potential with quantum numbers $\\Sigma_g^+$.",
        "positive": "$|V_{ub}|$ determination in lattice QCD: The 2012 PDG reports a tension at the level of $3 \\sigma$ between two\nexclusive determinations of $|V_{ub}|$. They are obtained by combining the\nexperimental branching ratios of $B \\to \\tau \\nu$ and $B \\to \\pi l \\nu$\n(respectively) with a theoretical computation of the hadronic matrix elements\n$\\fB$ and the $B \\to \\pi$ form factor $f_+(q^2)$. To understand the tension,\nimproved precision and a careful analysis of the systematics involved are\nnecessary. We report the results of the ALPHA collaboration for $\\fB$ from the\nlattice with 2 flavors of $O(a)$ improved Wilson fermions. We employ HQET,\nincluding $1/m_b$ corrections, with pion masses ranging down to $\\approx$ 190\nMeV. Renormalization and matching were performed non-perturbatively, and three\nlattice spacings reaching $a^{-1}\\approx 4.1$ GeV are used in the continuum\nextrapolation. We also present progress towards a computation of $f_+(q^2)$, to\ndirectly compare two independent exclusive determinations of $|V_{ub}|$ with\neach other and with inclusive determinations. Additionally, we report on\npreliminary results for $\\fBq{s}$, needed for the analysis of $B_s \\to\n\\mu^+\\mu^-$.}"
    },
    {
        "anchor": "Lattice formulations of supersymmetric gauge theories with matter fields: Certain classes of supersymmetric gauge theories, including the well known\nN=4 supersymmetric Yang-Mills theory, that takes part in the AdS/CFT\ncorrespondence, can be formulated on a Euclidean spacetime lattice using the\ntechniques of exact lattice supersymmetry. Great ideas such as topological\nfield theories, Dirac-Kaehler fermions, geometric discretization all come\ntogether to create supersymmetric lattice theories that are gauge-invariant,\ndoubler free, local and exact supersymmetric. We discuss the recent lattice\nconstructions of supersymmetric Yang-Mills theories in two and three dimensions\ncoupled to matter fields in various representations of the color group.",
        "positive": "Sphalerons and Other Saddles from Cooling: We describe a new cooling algorithm for SU(2) lattice gauge theory. It has\nany critical point of the energy or action functional as a fixed point. In\nparticular, any number of unstable modes may occur. We also provide insight in\nthe convergence of the cooling algorithms. A number of solutions will be\ndiscussed, in particular the sphalerons for twisted and periodic boundary\nconditions which are important for the low-energy dynamics of gauge theories.\nFor a unit cubic volume we find a sphaleron energy of resp. $\\cE_s=34.148(2)$\nand $\\cE_s=72.605(2)$ for the twisted and periodic case. Remarkably, the\nmagnetic field for the periodic sphaleron satisfies at all points $\\Tr\nB_x^2=\\Tr B_y^2=\\Tr B_z^2$."
    },
    {
        "anchor": "Bosonic color-flavor transformation for the special unitary group: We extend Zirnbauer's color-flavor transformation in the bosonic sector to\nthe color group SU(N_c). Because the flavor group U(N_b, N_b) is non-compact,\nthe algebraic method by which the original color-flavor transformation was\nderived leads to a useful result only for 2N_b \\le N_c. Using the character\nexpansion method, we obtain a different form of the transformation in the\nextended range N_b \\le N_c. This result can also be used for the color group\nU(N_c). The integrals to which the transformation can be applied are of\nrelevance for the recently proposed boson-induced lattice gauge theory.",
        "positive": "Improved Staggered Fermion Actions for QCD Thermodynamics: We analyze the cut-off dependence of the fermion contribution to the finite\ntemperature free energy density in ${\\cal O}(g^2)$ lattice perturbation theory\nfor several improved staggered fermion actions. Cut-off effects are drastically\nreduced for the Naik action and an action with improved rotational symmetry of\nthe quark propagator. We show that improvement of rotational symmetry at ${\\cal\nO}(g^2)$ further reduces cut-off effects in thermodynamic observables. We also\nshow that the introduction of fat-links does not have a significant influence\non cut-off distortions at ${\\cal O}(g^2)$."
    },
    {
        "anchor": "Hyperon-Nucleon Interaction from Lattice QCD at\n  ${(m_\u03c0,m_K)\\approx(146,525)}$ MeV: Comprehensive study of generalized baryon-baryon ($BB$) interaction including\nstrangeness is one of the important subject of nuclear physics. In order to\nobtain a complete set of isospin-base baryon interactions, we perform a large\nscale lattice QCD calculation with almost physical quark masses corresponding\nto $(m_\\pi,m_K)\\approx(146,525)$ MeV and large volume $(La)^4=(96a)^4\\approx$\n(8.1 fm)$^4$. A large number of Nambu-Bethe-Salpeter (NBS) correlation\nfunctions from nucleon-nucleon ($NN$) to $\\Xi\\Xi$ are calculated\nsimultaneously. In this contribution, we focus on the strangeness $S=-1$\nchannels of the hyperon interactions by means of HAL QCD method. Three\npotentials ((i) the $^1S_0$ central, (ii) the $^3S_1-^3D_1$ central, and (iii)\n$^3S_1-^3D_1$ tensor potentials) are presented for four isospin components; (1)\nthe $\\Sigma N - \\Sigma N$ (the isospin $I=3/2$) diagonal, (2) the $\\Lambda N -\n\\Lambda N$ diagonal, (3) the $\\Lambda N \\rightarrow \\Sigma N$ transition, and\n(4) the $\\Sigma N - \\Sigma N$ ($I=1/2$) diagonal. Scattering phase shifts for\n$\\Sigma N$ $(I=3/2)$ system are presented.",
        "positive": "Monte Carlo Simulation Calculation of Critical Coupling Constant for\n  Continuum \u03c6^4_2: We perform a Monte Carlo simulation calculation of the critical coupling\nconstant for the continuum {\\lambda \\over 4} \\phi^4_2 theory. The critical\ncoupling constant we obtain is [{\\lambda \\over \\mu^2}]_crit=10.24(3)."
    },
    {
        "anchor": "Extracting Physics from Topologically Frozen Markov Chains: In Monte Carlo simulations with a local update algorithm, the\nauto-correlation with respect to the topological charge tends to become very\nlong. In the extreme case one can only perform reliable measurements within\nfixed sectors. We investigate approaches to extract physical information from\nsuch topologically frozen simulations. Recent results in a set of sigma-models\nand gauge theories are encouraging. In a suitable regime, the correct value of\nsome observable can be evaluated to a good accuracy. In addition there are ways\nto estimate the value of the topological susceptibility.",
        "positive": "Nature of the $a_1$ meson in lattice quantum chromodynamics studied with\n  chiral fermions: We study the $a_1$ meson using a quenched lattice quantum chromodynamics\nsimulation with the truncated overlap fermions formalism based on the domain\nwall fermions. The obtained lightest mass of the $a_1$ meson, 1272(45) MeV, is\nconsistent with the experimental value for $a_1$(1260). Thus, $a_1$(1260) can\nbe identified to have a simple two-body constituent-quark structure. Our\nquenched simulation result of $a_1$(1420) can not explain the experimental mass\nvalue, which suggests $a_1$(1420) is not a simple $q\\bar{q}$ two quark state."
    },
    {
        "anchor": "Scaling with a modified Wilson action which suppresses Z_2 artifacts in\n  SU(2) lattice gauge theories: A modified Wilson action which suppresses plaquettes which take negative\nvalues is used to study the scaling behavior of the string tension. The use of\nthe $\\b_E$ scheme gives good agreement with asymptotic two loop results.",
        "positive": "New lattice results for SU(2) gauge theory with one adjoint Dirac flavor: Motivated by recent scenarios of exotic infrared behaviour and by earlier\nlattice findings, we present results for the SU(2) gauge theory with one Dirac\nflavor in the adjoint representation. This provides a major update on our\nprevious investigation of this theory, including data for four values of the\ngauge coupling $\\beta$, and for smaller masses and larger volumes than\npreviously considered. Results for the particle spectrum, topological\nobservables, and the anomalous dimension from both hyperscaling and the Dirac\nmode number are presented. At the finest coupling, we observe a mass anomalous\ndimension of $\\gamma_* \\gtrsim 0.6$. Our findings are analysed in relation to\npossible infrared behaviours of the model. In particular, we show that our\nresults are not compatible with a confining scenario in which chiral symmetry\nis broken."
    },
    {
        "anchor": "Energy-momentum tensor correlators and spectral functions: We calculate the thermal Euclidean correlators and the spectral functions of\nthe energy-momentum tensor for pure gauge theories, including at non-zero\nspatial momentum, at leading order in perturbation theory. Our goal is to\nimprove the extraction of transport properties from Euclidean correlators that\nare computable in lattice QCD. Based on our results and the predictions of\nhydrodynamics for the structure of the spectral functions at low frequencies,\nwe show that the shear and bulk viscosities can advantageously be extracted\nfrom the Euclidean correlators of the conserved charges, energy and momentum,\nat small but non-vanishing spatial momentum. The spectral functions in these\nchannels are free of the ultraviolet $\\omega^4$ term which represents a large\nbackground to the thermal physics encoded in the correlators of the fluxes.",
        "positive": "A lattice study of the quark propagator and vertex function: We report on the status of a study of the quark propagator and quark-gluon\nvertex in momentum space. Quark propagators have been generated at beta=6.0\nusing the O(a)-improved Sheikholeslami-Wohlert action and fixed to the Landau\ngauge. The first results for the quark pole mass and field renormalisation\nconstant are reported, and plans for future work are presented."
    },
    {
        "anchor": "Exploring confinement in SU(N) gauge theories with double-trace Polyakov\n  loop deformations: Recent results applying resurgence theory to finite-temperature field\ntheories yield a detailed analytic structure determined by topological\nexcitations. We examine finite-temperature SU(N) lattice gauge theories in\nlight of these results. Double-trace Polyakov loop deformations move through\ndifferent regions of the confined phase characterized by continuous change in\nthe adjoint Polyakov loop. Lattice models show how the behavior of monopole\nconstituents of calorons can change in the different confining regions. We\nconjecture that the pure SU(N) gauge theory is close to a special symmetric\npoint where monopole effects give rise to Casimir string-tension scaling.",
        "positive": "Zero modes, Instantons, and Monopoles: The purpose of this study is to show the relations between monopoles\ninstantons and Chiral symmetry breaking. First, in order to show the relation\nbetween instantons and monopoles, we generate configurations, adding monopoles\nby a monopole creation operator. Then, we count the number of fermion zero\nmodes in the configurations using Overlap fermions as a tool. As a result we\nfind that one monopole with plus one charge and one anti-monopole with minus\none charge make one instanton of charge plus or minus one. We have already\nreported these results elsewhere. In addition, in this report, the relation\nbetween the additional monopoles and Chiral symmetry breaking is discussed. We\ncompute the Chiral condensate, the pseudo-scalar mass, and the pion decay\nconstant. Preliminary results show that the additional monopoles do affect\nChiral symmetry breaking."
    },
    {
        "anchor": "Topological and magnetic properties of the QCD vacuum probed by overlap\n  fermions: We study some of the local CP-odd and magnetic properties of the non-Abelian\nvacuum with use of overlap fermions within the quenched lattice gauge theory.\nAmong these properties are the following: inhomogeneous spatial distribution of\nthe topological charge density (chirality for massless fermions) in SU(2)\ngluodynamics (for uncooled gauge configurations the chirality is localized on\nlow-dimensional defects with d=2..3, while a sequence of cooling steps gives\nrise to four-dimensional instantons and hence a four-dimensional structure of\nthe chirality distribution); finite local fluctuations of the chirality growing\nwith the strength of an external magnetic field; magnetization and\nsusceptibility of the QCD vacuum in SU(3) theory; magnetic catalysis of the\nchiral symmetry breaking, and the electric conductivity of the QCD vacuum in\nstrong magnetic fields.",
        "positive": "SU(2) and SU(3) chiral perturbation theory analyses on baryon masses in\n  2+1 flavor lattice QCD: We investigate the quark mass dependence of baryon masses in 2+1 flavor\nlattice QCD using SU(3) heavy baryon chiral perturbation theory up to one-loop\norder. The baryon mass data used for the analyses are obtained for the\ndegenerate up-down quark mass of 3 MeV to 24 MeV and two choices of the strange\nquark mass around the physical value. We find that the SU(3) chiral expansion\nfails to describe both the octet and the decuplet baryon data if\nphenomenological values are employed for the meson-baryon couplings. The SU(2)\ncase is also examined for the nucleon. We observe that higher order terms are\ncontrolled only around the physical point. We also evaluate finite size effects\nusing SU(3) heavy baryon chiralperturbation theory, finding small values of\norder 1% even at the physical point."
    },
    {
        "anchor": "Reducing Discretization Errors in Lattice QCD Spectroscopy: The improved Wilson quark action - the clover action - is constructed to have\nsmaller discretization errors than the normal Wilson quark action. We test this\nin a quenched spectroscopy computation on 6 lattice ensembles with spacings\nfrom 0.15 to 0.43 fm. To ensure that the dominant scaling violations come from\nthe fermions we use an $O(a^2)$ improved 6-link $SU(3)$ pure gauge action. We\nfind evidence that fermionic scaling violations are consistent with $O(a^2)$\nfor clover fermions and $O(a)$ with a nonnegligible $O(a^2)$ term for standard\nWilson fermions. This latter mixed ansatz makes a reliable continuum\nextrapolation problematic for Wilson fermions. For clover fermions, on the\nother hand, we obtain accurate predictions for hadron masses in quenched\ncontinuum QCD. We find that the slopes of the scaling violations are roughly\n200 MeV for both Wilson and clover fermions.",
        "positive": "QED$_3$ with Dynamical Fermions in an External Magnetic Field: In this paper, we present results of numerical lattice simulations of\ntwo-flavor QED in three space-time dimensions. First, we provide evidence that\nchiral symmetry is spontaneously broken in the chiral and continuum limit. Next\nwe discuss the role of an external magnetic field $B$ on the dynamically\ngenerated fermion mass. We investigate the $B$-dependence of the condensate\nthrough calculations with dynamical fermions using the non-compact formulation\nof the gauge field, and compare the results with those of a comparable study\nusing the quenched approximation."
    },
    {
        "anchor": "Stout-link smearing in lattice fermion actions: The properties of the momentum space quark propagator in Landau gauge are\nstudied for the overlap quark action in quenched lattice QCD. Numerical\ncalculations are performed over four ensembles of gauge configurations, where\nthree are smeared using either 1, 3, or 6 sweeps of stout-link smearing. We\ncalculate the non-perturbative wave function renormalization function $Z(p)$\nand the non-perturbative mass function $M(p)$ for a variety of bare quark\nmasses. We find that the wave-function renormalization function is slightly\nsensitive to the number of stout-link smearing sweeps. For the mass function we\nfind the effect of the stout-link smearing algorithm to be small for moderate\nto light bare quark masses. For a heavy bare quark mass we find a strong\ndependence on the number of smearing sweeps.",
        "positive": "Phase structure of finite density QCD with a histogram method: We study the phase structure of QCD in the $T-\\mu$ plane using a histogram\nmethod and the reweighting technique by performing phase quenched simulations\nof two-flavor QCD with RG-improved gauge action and O($a$) improved Wilson\nquark action. Taking the effects of the complex phase of the quark determinant\nusing the cumulant expansion method, we calculate the probability distribution\nfunction of plaquette and phase-quenched determinant as a function of $T$ and\n$\\mu$. We discuss the order of the QCD phase transition consulting the shape of\nthe probability distribution function."
    },
    {
        "anchor": "Exotics in the $\u03c0D$ system: In this proceedings we consider several states, namely the $D^*_{s0}(2317)$,\n$D_{s1}(2460)$, $D^*_{0}(2300)$ and $D_{1}(2430)$, which appear to defy\ndescription as simple quark-antiquark pairs. Theoretical input from unitarized\nchiral perturbation theory suggests they can be understood as emerging from\nGoldstone-Boson--$D$-meson scattering.\n  We present results from an $SU(3)$ flavor-symmetric lattice QCD simulation at\nlarge pion masses suggesting that there exists a $\\pi D$ bound state in the\nflavor-sextet representation that cannot emerge for quark-antiquark states, but\nthat appears naturally from the multiquark states. Moreover, we find repulsion\nin the [15] representation, which establishes the pattern predicted for the\ninteractions of Goldstone bosons with $D$ mesons. This suggests these states\nmay have the structure of hadronic molecules.",
        "positive": "Renormalization of the Lattice HQET Isgur-Wise Function: We compute the perturbative renormalization factors required to match to the\ncontinuum Isgur-Wise function, calculated using lattice Heavy Quark Effective\nTheory. The velocity, mass, wavefunction and current renormalizations are\ncalculated for both the forward difference and backward difference actions for\na variety of velocities. Subtleties are clarified regarding tadpole\nimprovement, regulating divergences, and variations of techniques used in these\nrenormalizations."
    },
    {
        "anchor": "Lattice QCD and dense quark matter: This talk summarizes recent progress in lattice QCD for dense quark matter.\nThe emphasis is on the insights obtained from analytical results derived within\nchiral perturbation theory.",
        "positive": "Two-dimensional $\\mathcal{N}=2$ Super-Yang-Mills Theory: Supersymmetry is one of the possible scenarios for physics beyond the\nstandard model. The building blocks of this scenario are supersymmetric gauge\ntheories. In our work we study the $\\mathcal{N}=1$ Super-Yang-Mills (SYM)\ntheory with gauge group SU(2) dimensionally reduced to two-dimensional\n$\\mathcal{N}=2$ SYM theory. In our lattice formulation we break supersymmetry\nand chiral symmetry explicitly while preserving R symmetry. By fine tuning the\nbar-mass of the fermions in the Lagrangian we construct a supersymmetric\ncontinuum theory. To this aim we carefully investigate mass spectra and Ward\nidentities, which both show a clear signal of supersymmetry restoration in the\ncontinuum limit."
    },
    {
        "anchor": "QCD Thermodynamics at $N_t=8$ and 12: We present results from studies of high temperature QCD with two flavors of\nKogut-Susskind quarks on $16^3\\times 8$ lattices at a quark mass of\n$am_q=0.00625$ and on $24^3\\times 12$ lattices at quark masses $am_q=0.008$ and\n0.016. The value of the crossover temperature is consistent with that obtained\non coarser lattices and/or at larger quark masses. Results are presented for\nthe chiral order parameter and for the baryon number susceptibility.",
        "positive": "QCD Thermodynamics: Recent results on QCD thermodynamics are presented. The nature of the T>0\ntransition is determined, which turns out to be an analytic cross-over. The\nabsolute scale for this transition is calculated. The temperature dependent\nstatic potential is given. The results were obtained by using a Symanzik\nimproved gauge and stout-link improved fermionic action. In order to approach\nthe continuum limit four different sets of lattice spacings were used with\ntemporal extensions N_t=4, 6, 8 and 10 (they correspond to lattice spacings a\n\\sim 0.3, 0.2, 0.15 and 0.12 fm). A new technique is presented, which --in\ncontrast to earlier methods-- enables one to determine the equation of state at\nvery large temperatures."
    },
    {
        "anchor": "Lattice QCD study of doubly-charmed strange baryons: We present the energy spectra of the low lying doubly-charmed baryons using\nlattice quantum chromodynamics. We precisely predict the ground state mass of\nthe charmed-strange Omega(cc) (1/2+) baryon to be 3712(11)(12) MeV which could\nwell be the next doubly-charmed baryon to be discovered at the LHCb experiment\nat CERN. We also predict masses of other doubly-charmed strange baryons with\nquantum numbers 3/2+, 1/2-, and 3/2-.",
        "positive": "$\u03c0-\u03c0$ scattering, QED and finite-volume quantization: Using the Coulomb gauge formulation of QED we present a lattice QCD procedure\nto calculate the $\\pi^+\\pi^+$ scattering phase shift including the effects of\nthe Coulomb potential which appears in this formulation. The approach described\nhere incorporates the effects of relativity and avoids finite-volume\ncorrections that vanish as a power of the volume in which the lattice\ncalculation is performed. This is the first step in developing a complete\nlattice QCD calculation of the electromagnetic and isospin-breaking light-quark\nmass contributions to $\\varepsilon'$, the parameter describing direct CP\nviolating effects in $K_L\\to\\pi\\pi$ decay."
    },
    {
        "anchor": "Glue Ball Masses and the Chameleon Gauge: We introduce a new numerical technique to compute mass spectra, based on\ndifference method and on a new gauge fixing procedure. We show that the method\nis very effective by test runs on a $SU(2)$ lattice gauge theory.",
        "positive": "Families index theory for Overlap lattice Dirac operator. I: The index bundle of the Overlap lattice Dirac operator over the orbit space\nof lattice gauge fields is introduced and studied. Obstructions to the\nvanishing of gauge anomalies in the Overlap formulation of lattice chiral gauge\ntheory have a natural description in this context. Our main result is a formula\nfor the topological charge (integrated Chern character) of the index bundle\nover even-dimensional spheres in the orbit space. It reduces under suitable\nconditions to the topological charge of the usual (continuum) index bundle in\nthe classical continuum limit (this is announced and sketched here; the details\nwill be given in a forthcoming paper). Thus we see that topology of the index\nbundle of the Dirac operator over the gauge field orbit space can be captured\nin a finite-dimensional lattice setting."
    },
    {
        "anchor": "Holography for Ising spins on the hyperbolic plane: Motivated by the AdS/CFT correspondence, we use Monte Carlo simulation to\ninvestigate the Ising model formulated on tessellations of the two-dimensional\nhyperbolic disk. We focus in particular on the behavior of boundary-boundary\ncorrelators, which exhibit power-law scaling both below and above the bulk\ncritical temperature indicating scale invariance of the boundary theory at any\ntemperature. This conclusion is strengthened by a finite-size scaling analysis\nof the boundary susceptibility which yields a scaling exponent consistent with\nthe scaling dimension extracted from the boundary correlation function. This\nobservation provides evidence that the connection between continuum boundary\nconformal symmetry and isometries of the bulk hyperbolic space survives for\nsimple interacting field theories even when the bulk is approximated by a\ndiscrete tessellation.",
        "positive": "Three-particle finite-volume formalism for $\u03c0^+\u03c0^+ K^+$ and related\n  systems: We consider three-particle systems consisting of two identical particles and\na third that is different, with all being spinless. Examples include\n$\\pi^+\\pi^+ K^+$ and $K^+K^+\\pi^+$. We derive the formalism necessary to\nextract two- and three-particle infinite-volume scattering amplitudes from the\nspectrum of such systems in finite volume. We use a relativistic formalism\nbased on an all-orders diagrammatic analysis in generic effective field theory,\nadopting the methodology used recently to study the case of three nondegenerate\nparticles. We present both a direct derivation, and also a cross-check based on\nan appropriate limit and projection of the fully nondegenerate formalism. We\nalso work out the threshold expansions for the three-particle K matrix that\nwill be needed in practical applications, both for systems with two identical\nparticles plus a third, and also for the fully nondegenerate theory."
    },
    {
        "anchor": "Monte Carlo study of real time dynamics: Monte Carlo studies involving real time dynamics are severely restricted by\nthe sign problem that emerges from highly oscillatory phase of the path\nintegral. In this letter, we present a new method to compute real time\nquantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo\nsimulations. The key idea is to deform the path integration domain to a complex\nmanifold where the phase oscillations are mild and the sign problem is\nmanageable. We use the previously introduced \"contraction algorithm\" to create\na Markov chain on this alternative manifold. We substantiate our approach by\nanalyzing the quantum mechanical anharmonic oscillator. Our results are in\nagreement with the exact ones obtained by diagonalization of the Hamiltonian.\nThe method we introduce is generic and in principle applicable to quantum field\ntheory albeit very slow. We discuss some possible improvements that should\nspeed up the algorithm.",
        "positive": "Resummation of Cactus Diagrams in Lattice QCD: We show how to perform a resummation, to all orders in perturbation theory,\nof a certain class of gauge invariant diagrams in Lattice QCD. These diagrams\nare often largely responsible for lattice artifacts. Our resummation leads to\nan improved perturbative expansion. Applied to a number of cases of interest,\nthis expansion yields results remarkably close to corresponding nonperturbative\nestimates."
    },
    {
        "anchor": "The Landau gauge gluon propagator in 4D SU(2) lattice gauge theory\n  revisited: Gribov copies and scaling properties: Lattice results for the gluon propagator in SU(2) pure gauge theory obtained\non large lattices are presented. Simulated annealing is used throughout to fix\nthe Landau gauge. We concentrate on checks for Gribov copy effects and for\nscaling properties. Our findings are similar to the ones in the SU(3) case,\nsupporting the decoupling-type infrared behaviour of the gluon propagator.",
        "positive": "Confinement, Casimir scaling and phase transitions in G(2) gauge\n  theories: We present an efficient local hybrid Monte-Carlo algorithm to investigate\nG(2) gluodynamics with and without Higgs field in 3 and 4 dimensions.\nAdditionaly we implemented a modified version of the multi-level\nL\\\"uscher-Weisz algorithm with exponential error reduction to measure\nexpectation values of Wilson and Polyakov loops. In three dimensions we show\nthat at intermediate scales the potential between static charges in the eight\nlowest-dimensional representations of G(2) scale with the eigenvalues of the\nquadratic Casimir operator. For the fundamental representations we detect\nstring breaking for larger separations of the charges at precisely the scale\npredicted by the mass of the created pair of glue-lumps. In four dimensions we\nexplored the phase diagram of the G(2) Gauge Higgs model showing that a line of\nfirst order confinement-deconfinement phase transitions connects G(2) and SU(3)\ngluodynamics and a line of second order phase transitions separates the two\ndeconfinement phases."
    },
    {
        "anchor": "Detecting flavor content of the vacuum using the Dirac operator spectrum: We compute the overlap Dirac spectrum on three ensembles generated using 2+1\nflavor domain wall fermions. The spectral density is determined up to\n$\\lambda\\sim$100 MeV with sub-percentage statistical uncertainty. The three\nensembles have different lattice spacings and two of them have quark masses\ntuned to the physical point. We show that we can resolve the flavor content of\nthe sea quarks and constrain their masses using the Dirac spectral density. We\nfind that the density is close to a constant below $\\lambda\\le$ 20 MeV (but\n10\\% higher than that in the 2-flavor chiral limit) as predicted by chiral\nperturbative theory ($\\chi$PT), and then increases linearly due to the strange\nquark mass. Using the next to leading order $\\chi$PT, one can extract the light\nand strange quark masses with $\\sim$20\\% uncertainties. Using the\nnon-perturbative RI/MOM renormalization, we obtain the chiral condensates at\n$\\overline{\\textrm{MS}}$ 2 GeV as $\\Sigma=(260.3(0.7)(1.3)(0.7)(0.8)\\\n\\textrm{MeV})^3$ in the $N_f=2$ (keeping the strange quark mass at the physical\npoint) chiral limit and $\\Sigma_0=(232.6(0.9)(1.2)(0.7)(0.8)\\ \\textrm{MeV})^3$\nin the $N_f=3$ chiral limit, where the four uncertainties come from the\nstatistical fluctuation, renormalization constant, continuum extrapolation and\nlattice spacing determination. Note that {$\\Sigma/\\Sigma_0=1.40(2)(2)$ is much\nlarger than 1} due to the strange quark mass effect.",
        "positive": "Low-Energy Effective Theories of Quantum Link and Quantum Spin Models: Quantum spin and quantum link models provide an unconventional regularization\nof field theory in which classical fields arise via dimensional reduction of\ndiscrete variables. This D-theory regularization leads to the same continuum\ntheories as the conventional approach. We show this by deriving the low-energy\neffective Lagrangians of D-theory models using coherent state path integral\ntechniques. We illustrate our method for the $(2+1)$-d Heisenberg quantum spin\nmodel which is the D-theory regularization of the 2-d O(3) model. Similarly, we\nprove that in the continuum limit a $(2+1)$-d quantum spin model with\n$SU(N)_L\\times SU(N)_R\\times U(1)_{L=R}$ symmetry is equivalent to the 2-d\nprincipal chiral model. Finally, we show that $(4+1)$-d SU(N) quantum link\nmodels reduce to ordinary 4-d Yang-Mills theory."
    },
    {
        "anchor": "Contribution of disconnected diagrams to the hyperfine splitting of\n  charmonium: We discuss the contribution of OZI-suppressed diagrams to the hyperfine\nsplitting of charmonium in lattice QCD. We study valence quark mass regions\nfrom strange to charm quark masses. No contribution of the disconnected diagram\nis seen in the vector meson channel. In the pseudo-scalar channel and for\nvalence quark masses around the strange quark, the disconnected contribution\ninduces a considerable increase of the meson mass. This contribution quickly\ndecreases as the quark mass increases. For charmonium the effect is very small\nalthough a decrease of the pseudoscalar mass induced by the disconnected\ncontribution cannot be ruled out.",
        "positive": "Scaling laws for the 2d 8-state Potts model with Fixed Boundary\n  Conditions: We study the effects of frozen boundaries in a Monte Carlo simulation near a\nfirst order phase transition. Recent theoretical analysis of the dynamics of\nfirst order phase transitions has enabled to state the scaling laws governing\nthe critical regime of the transition. We check these new scaling laws\nperforming a Monte Carlo simulation of the 2d, 8-state spin Potts model. In\nparticular, our results support a pseudo-critical beta finite-size scaling of\nthe form beta(infinity) + a/L + b/L^2, instead of beta(infinity) + c/L^d +\nd/L^{2d}. Moreover, our value for the latent heat is 0.294(11), which does not\ncoincide with the latent heat analytically derived for the same model if\nperiodic boundary conditions are assumed, which is 0.486358..."
    },
    {
        "anchor": "Wilson loops to 20th order numerical stochastic perturbation theory: We calculate Wilson loops of various sizes up to 20 loops in SU(3) pure\nlattice gauge theory at different lattice sizes for Wilson gauge action using\nthe technique of numerical stochastic perturbation theory. This allows us to\ninvestigate the perturbative series for various Wilson loops at high loop\norders. We observe differences in the behavior of those series as function of\nthe loop order. Up to $n=20$ we do not find evidence for the factorial growth\nof the expansion coefficients often assumed to characterize an asymptotic\nseries. Based on the actually observed behavior we sum the series in a model\nparametrized by hypergeometric functions. Alternatively we estimate the total\nseries in boosted perturbation theory using information from the first 14\nloops. We introduce generalized ratios of Wilson loops of different sizes.\nTogether with the corresponding Wilson loops from standard Monte Carlo\nmeasurements they enable us to assess their non-perturbative parts.",
        "positive": "Higher Order Hybrid Monte Carlo at Finite Temperature: The standard hybrid Monte Carlo algorithm uses the second order integrator at\nthe molecular dynamics step. This choice of the integrator is not always the\nbest. Using the Wilson fermion action, we study the performance of the hybrid\nMonte Carlo algorithm for lattice QCD with higher order integrators in both\nzero and finite temperature phases and find that in the finite temperature\nphase the performance of the algorithm can be raised by use of the 4th order\nintegrator."
    },
    {
        "anchor": "Confinement, chiral symmetry, and the lattice: Two crucial properties of QCD, confinement and chiral symmetry breaking,\ncannot be understood within the context of conventional Feynman perturbation\ntheory. Non-perturbative phenomena enter the theory in a fundamental way at\nboth the classical and quantum level. Over the years a coherent qualitative\npicture of the interplay between chiral symmetry, quantum mechanical anomalies,\nand the lattice has emerged and is reviewed here.",
        "positive": "Large $N_c$ behaviour of lattice QCD in the heavy dense regime: Combining strong coupling and hopping expansion one can derive a\ndimensionally reduced effective theory of lattice QCD. This theory has a\nreduced sign problem, is amenable to analytic evaluation and was successfully\nused to study the cold and dense regime of QCD for sufficiently heavy quarks.\nWe show results from the evaluation of the effective theory for arbitrary $N_c$\nup to $\\kappa^4$. The inclusion of gauge corrections is also investigated. We\nfind that the onset transition to finite baryon number density steepens with\ngrowing $N_c$ even for $T \\neq 0$. This suggests that in the large $N_c$ limit\nthe onset transition is first order up to the deconfinement transition. Beyond\nthe onset, the pressure is shown to scale as $p \\sim N_c$ through three orders\nin the hopping expansion, which is characteristic for a phase termed quarkyonic\nmatter in the literature."
    },
    {
        "anchor": "SU(2) chiral perturbation theory low-energy constants from 2+1 flavor\n  staggered lattice simulations: We extract the next-to-leading-order low-energy constants \\bar\\ell_3 and\n\\bar\\ell_4 of SU(2) chiral perturbation theory, based on precise lattice data\nfor the pion mass and decay constant on ensembles generated by the\nWuppertal-Budapest Collaboration for QCD thermodynamics. These ensembles\nfeature 2+1 flavors of two-fold stout-smeared dynamical staggered fermions\ncombined with Symanzik glue, with pion masses varying from 135 to 435 MeV,\nlattice scales between 0.7 and 2.0 GeV, while m_s is kept fixed at its physical\nvalue. Moderate taste splittings and the scale being set through the pion decay\nconstant allow us to restrict ourselves to the taste pseudoscalar state and to\nuse formulas from continuum chiral perturbation theory. Finally, by dropping\nthe data points near 135 MeV from the fits, we can explore the range of pion\nmasses that is needed in SU(2) chiral perturbation theory to reliably\nextrapolate to the physical point.",
        "positive": "New results using the canonical approach to finite density QCD: We present some new results regarding simulations of finite density QCD based\non a canonical approach. A previous study has shown that such simulations are\nfeasible, at least on small lattices. In the current study, we investigate some\nof the issues left open: we study the errors introduced by our approximation of\nthe action and we show how to tune it to reduce the cost of the simulations\nwhile keeping the errors under control. To further reduce the cost of the\nsimulations, we check the reliability of reweighting method with respect to the\nbaryon number. Finally, using these optimizations, we carry out the simulations\nat larger densities than in our previous study to look for signals of a phase\ntransition."
    },
    {
        "anchor": "New algorithms for finite density QCD: Recent progress of the complex Langevin method and the Lefschetz thimble in\nconnection with the sign problem is reviewed. These methods rely on the\ncomplexification of the original field manifold and they allow direct\nsimulations of theories with non-real measures. Similarities and differences of\nthe two approaches are pointed out. Results using the complex Langevin method,\nwhich allows simulations to evade the sign problem in full QCD, are presented.\nPromising results of the thimble approach for non-gauge theories are also\ndiscussed.",
        "positive": "Doubled Lattice Chern-Simons-Yang-Mills Theories with Discrete Gauge\n  Group: We construct doubled lattice Chern-Simons-Yang-Mills theories with discrete\ngauge group $G$ in the Hamiltonian formulation. Here, these theories are\nconsidered on a square spatial lattice and the fundamental degrees of freedom\nare defined on pairs of links from the direct lattice and its dual,\nrespectively. This provides a natural lattice construction for\ntopologically-massive gauge theories, which are invariant under parity and\ntime-reversal symmetry. After defining the building blocks of the doubled\ntheories, paying special attention to the realization of gauge transformations\non quantum states, we examine the dynamics in the group space of a single\ncross, which is spanned by a single link and its dual. The dynamics is governed\nby the single-cross electric Hamiltonian and admits a simple quantum mechanical\nanalogy to the problem of a charged particle moving on a discrete space\naffected by an abstract electromagnetic potential. Such a particle might\naccumulate a phase shift equivalent to an Aharonov-Bohm phase, which is\nmanifested in the doubled theory in terms of a nontrivial ground-state\ndegeneracy on a single cross. We discuss several examples of these doubled\ntheories with different gauge groups including the cyclic group\n$\\mathbb{Z}(k)\\subset U(1)$, the symmetric group $S_3\\subset O(2)$, the binary\ndihedral (or quaternion) group $\\bar{D}_2\\subset SU(2)$, and the finite group\n$\\Delta(27)\\subset SU(3)$. In each case the spectrum of the single-cross\nelectric Hamiltonian is determined exactly. We examine the nature of the\nlow-lying excited states in the full Hilbert space, and emphasize the role of\nthe center symmetry for the confinement of charges. Whether the investigated\ndoubled models admit a non-Abelian topological state which allows for\nfault-tolerant quantum computation will be addressed in a future publication."
    },
    {
        "anchor": "Measuring charged particle polarizabilities on the lattice without\n  background fields: We show how to compute electromagnetic polarizabilities of charged hadrons\nwithout the use of background fields in lattice QCD. The low-energy behavior of\nthe Compton scattering amplitude is matched to matrix elements of\ncurrent-current correlation functions on the lattice. Working in momentum\nspace, formulas for electric polarizability ($\\alpha_E$) and magnetic\npolarizability ($\\beta_M$) are derived for both charged pion and proton.\nLattice four-point correlation functions are constructed from quark and gluon\nfields to be used in Monte-Carlo simulations. We also draw attention to the\npotential of four-point functions as a multi-purpose tool for hadron structure.",
        "positive": "Weakly bound $H$ dibaryon from SU(3)-flavor-symmetric QCD: We present the first study of baryon-baryon interactions in the continuum\nlimit of lattice QCD, finding unexpectedly large lattice artifacts.\nSpecifically, we determine the binding energy of the $H$ dibaryon at a single\nquark-mass point. The calculation is performed at six values of the lattice\nspacing $a$, using O($a$)-improved Wilson fermions at the SU(3)-symmetric point\nwith $m_\\pi=m_K\\approx 420$ MeV. Energy levels are extracted by applying a\nvariational method to correlation matrices of bilocal two-baryon interpolating\noperators computed using the distillation technique. Our analysis employs\nL\\\"uscher's finite-volume quantization condition to determine the scattering\nphase shifts from the spectrum and vice versa, both above and below the\ntwo-baryon threshold. We perform global fits to the lattice spectra using\nparametrizations of the phase shift, supplemented by terms describing\ndiscretization effects, then extrapolate the lattice spacing to zero. The phase\nshift and the binding energy determined from it are found to be strongly\naffected by lattice artifacts. Our estimate of the binding energy in the\ncontinuum limit of three-flavor QCD is $B_H^{\\text{SU(3)}_{\\rm\nf}}=4.56\\pm1.13_{\\rm stat}\\pm0.63_{\\rm syst}$ MeV."
    },
    {
        "anchor": "Third-order perturbative lattice and complex Langevin analyses of the\n  finite-temperature equation of state of non-relativistic fermions in one\n  dimension: We analyze the pressure and density equations of state of unpolarized\nnon-relativistic fermions at finite temperature in one spatial dimension. For\nattractively interacting regimes, we perform a third-order lattice perturbation\ntheory calculation, assess its convergence properties by comparing with hybrid\nMonte Carlo results (there is no sign problem in this regime), and demonstrate\nagreement with real Langevin calculations. For repulsive interactions, we\npresent lattice perturbation theory results as well as complex Langevin\ncalculations, with a modified action to prevent uncontrolled excursions in the\ncomplex plane. Although perturbation theory is a common tool, our\nimplementation of it is unconventional; we use a Hubbard-Stratonovich\ntransformation to decouple the system and automate the application of Wick's\ntheorem, thus generating the diagrammatic expansion, including symmetry\nfactors, at any desired order. We also present an efficient technique to tackle\nnested Matsubara frequency sums without relying on contour integration, which\nis independent of dimension and applies to both relativistic and\nnon-relativistic systems, as well as all energy-independent interactions. We\nfind exceptional agreement between perturbative and non-perturbative results at\nweak couplings, and furnish predictions based on complex Langevin at strong\ncouplings. We additionally present perturbative calculations of up to the\nfifth-order virial coefficient for repulsive and attractive couplings. Both the\nlattice perturbation theory and complex Langevin formalisms can easily be\nextended to a variety of situations including polarized systems, bosons, and\nhigher dimension.",
        "positive": "Exploring the chiral regime with dynamical overlap fermions: I report the status of the dynamical overlap fermion project by the JLQCD and\nTWQCD collaborations. So far, the simulations have been completed with two\nflavors of overlap sea quarks in a wide range of sea quark mass corresponding\nthe $p$-regime and the $\\epsilon$-regime on a $16^3\\times 32$ lattice at\n$a=$0.12 fm. More recently, runs with 2+1 flavors of sea quarks have also\nstarted. This talk mainly discusses the physics results on the $N_f=2$ lattice\nafter describing the lattice formulation and algorithms."
    },
    {
        "anchor": "Lattice QCD Determination of the Bjorken-$x$ Dependence of Parton\n  Distribution Functions at Next-to-next-to-leading Order: We report the first lattice QCD calculation of pion valence quark\ndistribution with next-to-next-to-leading order perturbative matching\ncorrection, which is done using two fine lattices with spacings $a=0.04$ fm and\n$0.06$ fm and valence pion mass $m_\\pi=300$ MeV, at boost momentum as large as\n$2.42$ GeV. As a crucial step to control the systematics, we renormalize the\npion valence quasi distribution in the recently proposed hybrid scheme, which\nfeatures a Wilson-line mass subtraction at large distances in coordinate space,\nand develop a procedure to match it to the $\\overline{\\rm MS}$ scheme. We\ndemonstrate that the renormalization and the perturbative matching in\nBjorken-$x$ space yield a reliable determination of the valence quark\ndistribution for $0.03\\lesssim x \\lesssim 0.80$ with 5-20\\% uncertainties.",
        "positive": "A non-perturbative determination of Z_V and b_V for O(a) improved\n  quenched and unquenched Wilson fermions: By considering the local vector current between nucleon states and imposing\ncharge conservation we determine, for $O(a)$ improved Wilson fermions, its\nrenormalisation constant and quark mass improvement coefficient. The\ncomputation is performed for both quenched and two flavour unquenched fermions."
    },
    {
        "anchor": "Multi-boson block factorization of fermions: The numerical computations of many quantities of theoretical and\nphenomenological interest are plagued by statistical errors which increase\nexponentially with the distance of the sources in the relevant correlators.\nNotable examples are baryon masses and matrix elements, the hadronic vacuum\npolarization and the light-by-light scattering contributions to the muon g-2,\nand the form factors of semileptonic B decays. Reliable and precise\ndeterminations of these quantities are very difficult if not impractical with\nstate-of-the-art standard Monte Carlo integration schemes. I will review a\nrecent proposal for factorizing the fermion determinant in lattice QCD that\nleads to a local action in the gauge field and in the auxiliary boson fields.\nOnce combined with the corresponding factorization of the quark propagator, it\npaves the way for multi-level Monte Carlo integration in the presence of\nfermions opening new perspectives in lattice QCD. Exploratory results on the\nimpact on the above mentioned observables will be presented.",
        "positive": "Lattice Study of Low-lying Nonet Scalar Mesons in Quenched Approximation: Using lattice QCD simulation in the quenched approximation, we study the\n$\\kappa$ meson, which is ^3P_0 in the quark model, and compare experimental and\nother lattice data. The $\\kappa$ is the lowest scalar meson with strangeness\nand constitutes the scalar nonet. The obtained mass is much higher than the\nrecent experimental value, and therefore the $\\kappa(800)$ is difficult to\nconsider as a simple two-body constituent-quark structure, and may have another\nunconventional structure."
    },
    {
        "anchor": "Lattice supersymmetry: A method is proposed for latticizing a class of supersymmetric gauge\ntheories, including N=4 super Yang-Mills. The technique is inspired by recent\nwork on ``deconstruction''. Part of the target theory's supersymmetry is\nrealized exactly on the lattice, reducing or eliminating the need for fine\ntuning. (Talk based on the paper \"Supersymmetry on a Spatial Lattice\",\nhep-lat/0206019, by D.B.K., Emmanuel Katz and Mithat Unsal).",
        "positive": "The High Density Region of QCD from an Effective Model: We study the high density region of QCD within an effective model obtained in\nthe frame of the hopping parameter expansion and choosing Polyakov-type loops\nas the main dynamical variables representing the fermionic matter. This model\nstill shows the so-called sign problem, a difficulty peculiar to non-zero\nchemical potential, but it permits the development of algorithms which ensure a\ngood overlap of the simulated Monte Carlo ensemble with the true one. We review\nthe main features of the model and present results concerning the dependence of\nvarious observables on the chemical potential and on the temperature, in\nparticular of the charge density and the Polykov loop susceptibility, which may\nbe used to characterize the various phases expected at high baryonic density.\nIn this way, we obtain information about the phase structure of the model and\nthe corresponding phase transitions and cross over regions, which can be\nconsidered as hints about the behaviour of non-zero density QCD."
    },
    {
        "anchor": "QCD thermodynamics from lattice calculations with non-equilibrium\n  methods: The SU(3) equation of state: A precise lattice determination of the equation of state in SU(3) Yang-Mills\ntheory is carried out by means of a simulation algorithm, based on Jarzynski's\ntheorem, that allows one to compute physical quantities in thermodynamic\nequilibrium, by driving the field configurations of the system out of\nequilibrium. The physical results and the computational efficiency of the\nalgorithm are compared with other state-of-the-art lattice calculations, and\nthe extension to full QCD with dynamical fermions and to other observables is\ndiscussed.",
        "positive": "Influence of Implementation on the Properties of Pseudorandom Number\n  Generators with a Carry Bit: We present results of extensive statistical and bit level tests on three\nimplementations of a pseudorandom number generator algorithm using the lagged\nFibonacci method with an occasional addition of an extra bit. First\nimplementation is the RCARRY generator of James, which uses subtraction. The\nsecond is a modified version of it, where a suggested error present in the\noriginal implementation has been corrected. The third is our modification of\nRCARRY such that it utilizes addition of the carry bit. Our results show that\nthere are no significant differences between the performance of these three\ngenerators."
    },
    {
        "anchor": "Chiral Gauge Models on a Lattice: Chiral gauge groups acting on a lattice fermion field are constructed such\nthat all fermion modes (doublers) have the same charge. Details are given for\nan abelian axial gauge group within a perturbative framework. An action based\non this group correctly reproduces the continuum gauge-current anomaly, while\npreserving global chiral symmetry, locality, rotational symmetry and\nhermiticity. A Wess-Zumino-like scalar field enters naturally to enforce exact\nchiral gauge invariance. The degeneracy amongst the doublers can be lifted as\nin a vector model.",
        "positive": "Approaching Conformality: We investigate the preconformal region of the phase diagram of SU(3) theories\nwith fundamental flavors. We have simulated SU(3) theories with six and eight\nfundamental flavors at volumes 32^3 x 64. We use the generated configurations\nto measure the string tension \\sigma and the w0 scale setting quantity\nextracted from the gradient flow. We show preliminary results on the ratios\nTc/\\sqrt{\\sigma} and Tc w0. We compare them to the behavior obtained at smaller\nNf and discuss the implications of our results."
    },
    {
        "anchor": "Probing the nature of phases across the phase transition at finite\n  isospin chemical potential: We compare the low eigenvalue spectra of the Overlap Dirac operator on two\nsets of configurations at $\\mu_I/\\mu_I^c$ = 0.5 and 1.5 generated with\ndynamical staggered fermions at these isospin chemical potential on $24^3\n\\times 6$ lattices. We find very small changes in the number of zero modes and\nlow lying modes which is in stark contrast with those across the corresponding\nfinite temperature phases where one sees a drop across the phase transition.\nPossible consequences are discussed.",
        "positive": "Finite Temperature QCD with Wilson Quarks: A Study with a\n  Renormalization Group Improved Gauge Action: Finite temperature transition in lattice QCD with degenerate Wilson quarks is\ninvestigated on an $N_t=4$ lattice, using a renormalization group improved\ngauge action. We find the following for the $N_F=2$ case:\n  1) The transition is smooth for a wide range of the quark mass.\n  2) The chiral transition is continuous.\n  3) The chiral condensation well satisfies a scaling relation with the\ncritical exponents of the 3 dimensional $O(4)$ spin model. For $N_F=3$, we find\nthat the chiral transition is of first order."
    },
    {
        "anchor": "The gluon propagator from large asymmetric lattices: The Landau-gauge gluon propagator is computed for the SU(3) gauge theory on\nlattices up to a size of $32^3 \\times 200$. We use the standard Wilson action\nat $\\beta = 6.0$ and compare our results with previous computations using large\nasymmetric and symmetric lattices. In particular, we focus on the impact of the\nlattice geometry and momentum cuts to achieve compatibility between data from\nsymmetric and asymmetric lattices for a large range of momenta.",
        "positive": "The Y-stringlike behavior of a static hadron at finite T: We look into the signatures of the effective Y-bosonic strings in the gluonic\nprofile due to a system of three static quarks on the lattice. The gluonic\ndistribution is calculated in pure Yang-Mills lattice gauge theory at finite\ntemperature with Polyakov loops operators. The analysis of the action density\nunveils a filled-$\\Delta$ distribution. However, we found that these\n$\\Delta$-shaped action density profiles are structured from three Y-shaped\nGaussian-like flux-tubes. The length of the revealed Y-flux system increases\nwith the increasing of the color source separation and reaches maximum near the\ndeconfinement point. The lattice data for the mean-square width of the gluonic\naction density have been compared to the corresponding width calculated based\non the string model at finite temperature. We assume Y-string configuration\nwith minimal length. The growth pattern of the action density of the gluonic\nfield fits well to junction fluctuations of the Y-baryonic string model for\nlarge quark separation at the considered temperatures."
    },
    {
        "anchor": "Quarkonium at finite temperature: Lattice QCD studies on charmonium at finite temperature are presented After a\ndiscussion about problems for the Maximum Entropy Method applied to finite\ntemperature lattice QCD, I show several results on charmonium spectral\nfunctions. The ``wave function'' of charmonium is also discussed to study the\nspatial correlation between quark and anti-quark in deconfinement phase.",
        "positive": "Detecting Lee-Yang/Fisher singularities by multi-point Pad\u00e8: The Bielefeld Parma Collaboration has in recent years put forward a method to\nprobe finite density QCD by the detection of Lee-Yang singularities. The\nlocation of the latter is obtained by multi-point Pad\\`e approximants, which\nare in turn calculated matching Taylor series results obtained from Monte Carlo\ncomputations at (a variety of values of) imaginary baryonic chemical potential.\nThe method has been successfully applied to probe the Roberge Weiss phase\ntransition and preliminary, interesting results are showing up in the vicinity\nof a possible QCD critical endpoint candidate. In this talk we will be\nconcerned with a couple of significant aspects in view of a more powerful\napplication of the method. First, we will discuss the possibility of detecting\nfinite size scaling of Lee-Yang/Fisher singularities in finite density\n(lattice) QCD. Second, we will briefly mention our attempts at detecting both\nsingularities in the complex chemical potential plane and singularities in the\ncomplex temperature plane. The former are obtained from rational approximations\nwhich are functions of the chemical potential at given values of the\ntemperature; the latter are obtained from rational approximations which are\nfunctions of the temperature at given values of the chemical potential."
    },
    {
        "anchor": "Transversity PDFs of the proton from lattice QCD with physical quark\n  masses: We present a lattice QCD calculation of the transversity isovector- and\nisoscalar-quark parton distribution functions (PDFs) of the proton utilizing a\nperturbative matching at next-to-leading-order (NLO) accuracy. Additionally, we\ndetermine the isovector and isoscalar tensor charges for the proton. In both\ncalculations, the disconnected contributions to the isoscalar matrix elements\nhave been ignored. The calculations are performed using a single ensemble of\n$N_f = 2 +1$ highly-improved staggered quarks simulated with physical-mass\nquarks and a lattice spacing of $a = 0.076$ fm. The Wilson-clover action, with\nphysical quark masses and smeared gauge links obtained from one iteration of\nhypercubic (HYP) smearing, is used in the valence sector. Using the NLO\noperator product expansion, we extract the lowest four to six Mellin moments\nand the PDFs from the matrix elements via a neural network. In addition, we\ncalculate the $x$-dependence of the PDFs with hybrid-scheme renormalization and\nthe recently developed leading-renormalon resummation technique, at NLO with\nthe resummation of leading small-$x$ logarithms.",
        "positive": "Gauge-invariant field-strength correlators in pure Yang-Mills and full\n  QCD at finite temperature: We study by numerical simulations on a lattice the behaviour of the\ngauge-invariant two-point correlation functions of the gauge-field strengths\nacross the deconfinement phase transition, both for the pure-gauge SU(3) theory\nand for full QCD with two flavours. Quenched data agree within errors with\nprevious determinations, but have much higher statistics. A best-fit analysis\nof the data has been performed, both for the quenched and the full-QCD case,\nshowing that the electric gluon condensate drops to zero at the deconfining\nphase transition."
    },
    {
        "anchor": "Bayesian Analysis of Many-Pole Fits of Hadron Propagators in Lattice QCD: We use Bayes' probability theorem to analyze many-pole fits of hadron\npropagators. An alternative method of estimating values and uncertainties of\nthe fit parameters is offered, which has certain advantages over the\nconventional methods. The probability distribution of the parameters of a fit\nis calculated. The relative probability of various models is calculated.",
        "positive": "Improved Hamiltonian Lattice Gauge Theory: We derive an improved lattice Hamiltonian for pure gauge theory, coupling\narbitrarily distant links in the kinetic term. The level of improvement\nachieved is examined in variational calculations of the SU(2) specific heat in\n2+1 dimensions."
    },
    {
        "anchor": "Variations on the Maiani-Testa approach and the inverse problem: We discuss a method to construct hadronic scattering and decay amplitudes\nfrom Euclidean correlators, by combining the approach of a regulated inverse\nLaplace transform with the work of Maiani and Testa. Revisiting the original\nresult, we observe that the key observation, i.e. that only threshold\nscattering information can be extracted at large separations, can be understood\nby interpreting the correlator as a spectral function, $\\rho(\\omega)$,\nconvoluted with the Euclidean kernel, $e^{- \\omega t}$, which is sharply peaked\nat threshold. We therefore consider a modification in which a smooth step\nfunction, equal to one above a target energy, is inserted in the spectral\ndecomposition. This can be achieved either through Backus-Gilbert-like methods\nor more directly using the variational approach. The result is a shifted\nresolution function, such that the large $t$ limit projects onto scattering or\ndecay amplitudes above threshold. The utility of this method is highlighted\nthrough large $t$ expansions of both three- and four-point functions that\ninclude leading terms proportional to the real and imaginary parts (separately)\nof the target observable. This work also presents new results relevant for the\nun-modified correlator at threshold, including expressions for extracting the\n$N \\pi$ scattering length from four-point functions and a new strategy to\norganize the large $t$ expansion that exhibits better convergence than the\nexpansion in powers of $1/t$.",
        "positive": "Hadronic Interactions from Lattice QCD: We present an overview of recent efforts to calculate the interactions among\nhadrons using lattice QCD. After outlining the techniques that are used to\nextract scattering parameters, we detail the latest calculations of meson-meson\nscattering, baryon-baryon scattering and multi-meson systems obtained with\ndomain-wall valence quarks on the staggered MILC lattices by the NPLQCD\ncollaboration. Estimates of the computational resources required to achieve\nprecision results in the baryon sector are presented."
    },
    {
        "anchor": "Critical behaviour of SU(2) lattice gauge theory. A complete analysis\n  with the $\u03c7^2$-method: We determine the critical point and the ratios $\\beta/\\nu$ and $\\gamma/\\nu$\nof critical exponents of the deconfinement transition in $SU(2)$ gauge theory\nby applying the $\\chi^2$-method to Monte Carlo data of the modulus and the\nsquare of the Polyakov loop. With the same technique we find from the Binder\ncumulant $g_r$ its universal value at the critical point in the thermodynamical\nlimit to $-1.403(16)$ and for the next-to-leading exponent $\\omega=1\\pm0.1$.\nFrom the derivatives of the Polyakov loop dependent quantities we estimate then\n$1/\\nu$. The result from the derivative of $g_r$ is $1/\\nu=0.63\\pm0.01$, in\ncomplete agreement with that of the $3d$ Ising model.",
        "positive": "Towards a chiral gauge theory by deconstruction in AdS5: We describe an implementation of a deconstructed gauge theory with charged\nfermions defined on an interval in five dimensional AdS space. The four\ndimensional slices are Minkowski, and the end slices support four dimensional\nchiral zero modes. In such a theory, the energy scales warp down as we move\nalong the fifth dimension. If we augment this theory with localized neutral\n4-dimensional Majorana fermions on the low energy end, and implement a Higgs\nmechanism there, we can arrange the theory such that the lightest gauge boson\nmode and the chiral mode on the wall at the high energy end are parametrically\nlighter than all the other states in the theory. If this semiclassical\nconstruction does not run into problems at the quantum level, this may provide\nan explicit construction of a chiral gauge theory. Instanton effects are\nexpected to make the gauge boson heavy only if the resulting effective theory\nis anomalous."
    },
    {
        "anchor": "Spectrum of the QCD flux tube in 3d SU(2) lattice gauge theory: Evidence from the lattice suggests that formation of a flux tube between a\n$q\\bar{q}$ pair in the QCD vacuum leads to quark confinement. For large\nseparations between the quarks, it is conjectured that the flux tube has a\nbehaviour similar to an oscillating bosonic string, supported by lattice data\nfor the groundstate $q\\bar{q}$ potential. We measure the excited states of the\nflux tube in 3d SU(2) gauge theory with three different couplings inside the\nscaling region. We compare our results to predictions of effective string\ntheories.",
        "positive": "Status of Average-x from Lattice QCD: As algorithms and computing power have advanced, lattice QCD has become a\nprecision technique for many QCD observables. However, the calculation of\nnucleon matrix elements remains an open challenge. I summarize the status of\nthe lattice effort by examining one observable that has come to represent this\nchallenge, average-x: the fraction of the nucleon's momentum carried by its\nquark constituents. Recent results confirm a long standing tendency to\novershoot the experimentally measured value. Understanding this puzzle is\nessential to not only the lattice calculation of nucleon properties but also\nthe broader effort to determine hadron structure from QCD."
    },
    {
        "anchor": "Lattice Gluon Propagator and One-Gluon-Exchange Potential: We consider the interquark potential in the one-gluon-exchange (OGE)\napproximation, using a fully nonperturbative gluon propagator from large-volume\nlattice simulations. The resulting VLGP potential is non-confining, showing\nthat the OGE approximation is not sufficient to describe the infrared sector of\nQCD. Nevertheless, it represents an improvement over the perturbative\n(Coulomb-like) potential, since it allows the description of a few low-lying\nbound states of charmonium and bottomonium. In order to achieve a better\ndescription of these spectra, we add to VLGP a linearly growing term. The\nobtained results are comparable to the corresponding ones in the\nCornell-potential case. As a byproduct of our study, we estimate the interquark\ndistance for the considered charmonium and bottomonium states.",
        "positive": "Eight very excited spectra and one possible axion in SU(3) lattice gauge\n  theory: We compute the spectra of flux tubes formed between a static quark antiquark\npair up to a significant number of excitations and for eight symmetries of the\nflux tubes, up to $\\Delta_u$, using pure $SU(3)$ gauge lattice QCD in 3+1\ndimensions. To accomplish this goal, we use a large set of appropriate\noperators, an anisotropic tadpole improved action, smearing techniques, and\nsolve a generalized eigenvalue problem. Moreover, we compare our results with\nthe Nambu-Goto string model to evaluate possible tensions which could be a\nsignal for novel phenomena. Especially, we provide evidence for the coupling of\na massive particle, say an axion, to the $\\Sigma_g^-$, $\\Sigma_u^-$, and\n$\\Sigma_u^{-*}$ flux tube with approximate masses $ 2.25\\sqrt{\\sigma}$,\n$1.85\\sqrt{\\sigma}$, $3.30\\sqrt{\\sigma}$, respectively."
    },
    {
        "anchor": "B meson decay constant with the Wilson and Clover heavy quark actions: We present results of our quenched study of the B meson decay constant\nobtained with a parallel set of simulations with the Wilson and Clover actions\nat \\beta=5.9, 6.1 and 6.3. Systematic errors associated with the large b-quark\nmass are analyzed within the Fermilab non-relativistic formalism. As our best\nestimate in the continuum limit we obtain $f_B=163 \\pm 16 MeV$ and $f_{B_s}=175\n\\pm 18 MeV$ with the Clover action.",
        "positive": "Wavelets as a variational basis of the XY model: We use Daubechies' orthonormal compact wavelets as a variational basis for\nthe $XY$ model in two and three dimensions. Assuming that the fluctuations of\nthe wavelet coefficients are Gaussian and uncorrelated, minimization of the\nfree energy yields the fluctuation strength of wavelet coefficients at\ndifferent scales, from which observables can be computed. This model is able to\ndescribe the low-temperature phase and makes a prediction about the phase\ntransition temperature."
    },
    {
        "anchor": "Monte Carlo calculation for systems consisting of several coordinate\n  patches: I investigate the time step dependence of Monte Carlo simulations for\ncoordinate-spaces consisting of several patches. It is shown that a naive\nkinetic term does not necessarily converge to the same spectrum as a\nHamiltonian calculation. Then an improved kinetic term is presented which\nallows one to connect the Monte Carlo and Rayleigh-Ritz results of intermediate\nvolume SU(2) gauge theory.",
        "positive": "$B \\rightarrow D^*$ vector, axial-vector and tensor form factors for the\n  full $q^2$ range from lattice QCD: We compute the complete set of SM and tensor $B_{(s)}\\to\nD_{(s)}^*\\ell\\bar{\\nu}$ semileptonic form factors across the full kinematic\nrange of the decay using second generation MILC $n_f=2+1+1$ HISQ gluon field\nconfigurations and HISQ valence quarks, with the heavy-HISQ method. Lattice\nspacings range from $0.09\\mathrm{fm}$ to $0.044\\mathrm{fm}$ with pion masses\nfrom $\\approx 300\\mathrm{MeV}$ down to the physical value and heavy quark\nmasses ranging between $\\approx 1.5 m_c$ and $4.1 m_c \\approx 0.9 m_b$;\ncurrents are normalised nonperturbatively. Using the recent $B_{(s)}\\to\nD^*_{(s)}\\ell\\bar{\\nu}_\\ell$ data from Belle and LHCb together with our form\nfactors we determine a model independent value of\n$V_{cb}=39.03(56)_\\mathrm{exp}(67)_\\mathrm{latt}\\times 10^{-3}$, in agreement\nwith previous exclusive determinations and in tension with the inclusive result\nat the level of $3.6\\sigma$. We observe a $\\approx 1\\sigma$ tension between the\nshape of the differential decay rates computed using our form factors and those\nmeasured by Belle. We compute a lattice-only SM value for the ratio of\nsemitauonic and semimuonic decay rates, $R(D^*)=0.273(15)$, which we find to be\ncloser to the recent Belle measurement and HFLAV average than theory\npredictions using fits to experimental differential rate data for $B\\to\nD^*\\ell\\bar{\\nu}_\\ell$. Determining $V_{cb}$ using the total rate for $B\\to\nD^*\\ell\\nu$ gives a value in agreement with inclusive results. We compute the\nlongitudinal polarisation fraction for the semitauonic mode,\n$F_L^{D^*}=0.395(24)$, which is in tension at the level of $2.2\\sigma$ with the\nrecent Belle measurement. Our calculation combines $B\\to D^*$ and $B_s\\to\nD_s^*$ lattice results, and we provide an update which supersedes our previous\nlattice computation of the $B_s\\to D_s^*$ form factors. We also give the chiral\nperturbation theory needed to analyse the tensor form factors."
    },
    {
        "anchor": "Tensor Charges and their Impact on Physics Beyond the Standard Model: The nucleon tensor charge, $g_T$, is an important quantity in the search for\nbeyond the Standard Model tensor interactions in neutron and nuclear\n$\\beta$-decays as well as the contribution of the quark electric dipole moment\n(EDM) to the neutron EDM. We present results from the QCDSF/UKQCD/CSSM\ncollaboration for the tensor charge, $g_T$, using lattice QCD methods and the\nFeynman-Hellmann theorem. We use a flavour symmetry breaking method to\nsystematically approach the physical quark mass using ensembles that span three\nlattice spacings.",
        "positive": "Lattice QCD without topology barriers: As the continuum limit is approached, lattice QCD simulations tend to get\ntrapped in the topological charge sectors of field space and may consequently\ngive biased results in practice. We propose to bypass this problem by imposing\nopen (Neumann) boundary conditions on the gauge field in the time direction.\nThe topological charge can then flow in and out of the lattice, while many\nproperties of the theory (the hadron spectrum, for example) are not affected.\nExtensive simulations of the SU(3) gauge theory, using the HMC and the closely\nrelated SMD algorithm, confirm the absence of topology barriers if these\nboundary conditions are chosen. Moreover, the calculated autocorrelation times\nare found to scale approximately like the square of the inverse lattice\nspacing, thus supporting the conjecture that the HMC algorithm is in the\nuniversality class of the Langevin equation."
    },
    {
        "anchor": "Nuclear Forces from Lattice QCD: A method to extract nucleon-nucleon (NN) potentials from the Bethe-Salpeter\namplitude in lattice QCD is presented. It is applied to the two nucleons on the\nlattice with quenched QCD simulations. By disentangling the mixing between the\nS-state and the D-state, we obtain central and tensor potentials in the leading\norder of the velocity expansion of the non-local NN potential. The spatial\nstructure, the quark mass dependence and the velocity dependence of the NN\npotential are analyzed. Preliminary result in (2+1)-flavor QCD simulations is\nalso shown.",
        "positive": "Chiral magnetization of non-Abelian vacuum: a lattice study: The chiral magnetization properties of cold and hot vacua are studied using\nquenched simulations in lattice Yang-Mills theory. In weak external magnetic\nfields the magnetization is proportional to the first power of the magnetic\nfield. We evaluate numerically the coefficient of the proportionality (the\nchiral susceptibility) using near-zero eigenmodes of overlap fermions. We found\nthat the product of the chiral susceptibility and the chiral condensate equals\nto 46(3) MeV. This value is very close to the phenomenological value of 50 MeV.\nIn strong fields the magnetization is a nonlinear function of the applied\nmagnetic field. We find that the nonlinear features of the magnetization are\nwell described by an inverse tangent function. The magnetization is weakly\nsensitive to temperature in the confinement phase."
    },
    {
        "anchor": "Neutral B-meson mixing from dynamical lattice QCD with chiral light\n  quarks and static b-quarks: In the limit of infinitely heavy b-quarks we compute the SU(3)-breaking ratio\nxi of neutral B-meson mixing matrix elements. We also present results for the\nratio of decay constants f_{B_s}/f_{B_d}. Our calculation employs\nchirality-preserving domain-wall fermions for the light quarks, a static action\nwith link-smearing for the b-quarks, and the Iwasaki gauge action. Here we\nreport on our results from the 16^3 x 32 x 16 ensemble (a^-1 = 1.729(28) GeV)\nwhich we use to verify our method. We improve upon our earlier work by\nincluding O(alpha_s pa) matching for the computation of the decay constants and\nextrapolating to the physical point using chiral perturbation theory.",
        "positive": "The order of the chiral transition in N_f=2 QCD: A strategy is developed to investigate the order of the transition using\nfinite size scaling and its relation to color confinement. An in-depth\nnumerical investigation has been performed with KS fermions on lattices with\nN_t=4 and N_s=12,16,20,24,32 and quark masses am_q ranging from 0.01335 to\n0.35. The specific heat and a number of susceptibilities have been measured and\ncompared with the expectation of an O(4) second order and a first order phase\ntransition. A second order O(4) is excluded, whilst data are consistent with a\nfirst order."
    },
    {
        "anchor": "Energy-momentum tensor on the lattice: non-perturbative renormalization\n  in Yang--Mills theory: We construct an energy-momentum tensor on the lattice which satisfies the\nappropriate Ward Identities (WIs) and has the right trace anomaly in the\ncontinuum limit. It is defined by imposing suitable WIs associated to the\nPoincare` invariance of the continuum theory. These relations come forth when\nthe length of the box in the temporal direction is finite, and they take a\nparticularly simple form if the coordinate and the periodicity axes are not\naligned. We implement the method for the SU(3) Yang--Mills theory discretized\nwith the standard Wilson action in presence of shifted boundary conditions in\nthe (short) temporal direction. By carrying out extensive numerical\nsimulations, the renormalization constants of the traceless components of the\ntensor are determined with a precision of roughly half a percent for values of\nthe bare coupling constant in the range 0<= g^2_0<=1.",
        "positive": "Finite Volume Corrections to the Two-Particle Decay of States with\n  Non-Zero Momentum: We study the effects of finite volume on the two-particle decay rate of an\nunstable state with non-zero momentum. First Luscher's field-theoretic relation\nbetween the infinite volume scattering phase shifts and the quantized energy\nlevels of a finite volume, two-particle system is generalized to the case of\nnon-zero total momentum and compared with the earlier results of Rummukainen\nand Gottlieb. We then use this result and the method of Lellouch and Luscher to\ndetermine the corrections needed for a finite-volume calculation of a\ntwo-particle decay amplitude when the decaying particle has non-vanishing\ncenter-of-mass momentum."
    },
    {
        "anchor": "Complex spectrum of finite-density lattice QCD with static quarks at\n  strong coupling: We calculate the spectrum of transfer matrix eigenvalues associated with\nPolyakov loops in finite-density lattice QCD with static quarks. These\neigenvalues determine the spatial behavior of Polyakov loop correlations\nfunctions. Our results are valid for all values of the gauge coupling in $1+1$\ndimensions, and valid in the strong-coupling region for any number of\ndimensions. When the quark chemical potential $\\mu$ is nonzero, the spatial\ntransfer matrix $T_s$ is non-Hermitian. The appearance of complex eigenvalues\nin $T_s$ is a manifestation of the sign problem in finite-density QCD. The\ninvariance of finite-density QCD under the combined action of charge\nconjugation $\\mathcal{C}$ and complex conjugation $\\mathcal{K}$ implies that\nthe eigenvalues of $T_s$ are either real or part of a complex pair. Calculation\nof the spectrum confirms the existence of complex pairs in much of the\ntemperature-chemical potential plane. Many features of the spectrum for static\nquarks are determined by a particle-hole symmetry. For $\\mu$ small compared to\nthe quark mass $M$, we typically find real eigenvalues for the lowest lying\nstates. At somewhat larger values of $\\mu,$ pairs of eigenvalues may form\ncomplex-conjugate pairs, leading to damped oscillatory behavior in Polyakov\nloop correlation functions. However, near $\\mu=M$, the low-lying spectrum\nbecomes real again. This is a direct consequence of the approximate\nparticle-hole symmetry at $\\mu=M$ for heavy quarks. This behavior of the\neigenvalues should be observable in lattice simulations and can be used as a\ntest of lattice algorithms. Our results provide independent confirmation of\nresults we have previously obtained in PNJL models using complex saddle points.",
        "positive": "Matching lattice and continuum four-fermion operators with\n  nonrelativistic QCD and highly improved staggered quarks: We match continuum and lattice heavy-light four-fermion operators at one loop\nin perturbation theory. For the heavy quarks we use nonrelativistic QCD and for\nthe massless light quarks the highly improved staggered quark action. We\ninclude the full set of $\\Delta B=2$ operators relevant to neutral $B$ mixing\nboth within and beyond the Standard Model and match through order $\\alpha_s$,\n$\\Lambda_{\\mathrm{QCD}}/M_b$, and $\\alpha_s/(aM_b)$."
    },
    {
        "anchor": "Further evidence that the transition of 4D dynamical triangulation is\n  1st order: We confirm recent claims that, contrary to what was generally believed, the\nphase transition of the dynamical triangulation model of four-dimensional\nquantum gravity is of first order. We have looked at this at a volume of 64,000\nfour-simplices, where the evidence in the form of a double peak histogram of\nthe action is quite clear.",
        "positive": "Extrapolation of lattice QCD results beyond the power-counting regime: Resummation of the chiral expansion is necessary to make accurate contact\nwith current lattice simulation results of full QCD. Resummation techniques\nincluding relativistic formulations of chiral effective field theory and\nfinite-range regularization (FRR) techniques are reviewed, with an emphasis on\nusing lattice simulation results to constrain the parameters of the chiral\nexpansion. We illustrate how the chiral extrapolation problem has been solved\nand use FRR techniques to identify the power-counting regime (PCR) of chiral\nperturbation theory. To fourth-order in the expansion at the 1% tolerance\nlevel, we find 0 \\le m_pi \\le 0.18 GeV for the PCR, extending only a small\ndistance beyond the physical pion mass."
    },
    {
        "anchor": "Z2 Monopoles, Vortices, and the Deconfinement Transition in Mixed Action\n  SU(2) Gauge Theory: Adding separate chemical potentials lambda and gamma for Z2 monopoles and\nvortices respectively in the Villain form of the mixed fundamental-adjoint\naction for the SU(2) lattice gauge theory, we investigate their role in the\ninterplay between the deconfinement and bulk phase transitions using Monte\nCarlo techniques. Setting lambda to be nonzero, we find that the line of\ndeconfinement transitions is shifted in the coupling plane but it behaves\ncuriously also like the bulk transition line for large enough adjoint coupling,\nas for lambda=0. In a narrow range of couplings, however, we find separate\ndeconfinement and bulk phase transitions on the same lattice for nonzero and\nlarge lambda, suggesting the two to be indeed coincident in the region where a\nfirst order deconfinement phase transition is seen. In the limit of large\nlambda and gamma, we obtain only lines of second order deconfinement phase\ntransitions, as expected from universality.",
        "positive": "Testing OPE for ghosts, gluons and $\u03b1_s$: We present here our results on extracting Wilson coefficients from different\nquantities such as ghost and gluon propagators which are calculated by means of\nLattice QCD. The results confirm the validity of our method for the calculation\nof the strong coupling constant as well as allow to estimate the range of\nmomenta where OPE is applicable."
    },
    {
        "anchor": "New Numerical Methods for Quantum Field Theories on the Continuum: The Source Galerkin Method is a new numerical technique that is being\ndeveloped to solve Quantum Field Theories on the continuum. It is not based on\nMonte Carlo techniques and has a measure to evaluate relative errors. It\npromises to increase the accuracy and speed of calculations, and takes full\nadvantage of symmetries of the theory. The application of this method to the\nnon-linear sigma model is outlined.",
        "positive": "Universal Renormalons in Principal Chiral Models: Perturbative expansions in many physical systems yield 'only' asymptotic\nseries which are not even Borel resummable. Interestingly, the corresponding\nambiguities point to nonperturbative physics. We numerically verify this\nrenormalon mechanism for the first time in two-dimensional sigma models, that,\nlike four-dimensional gauge theories, are asymptotically free and generate a\nstrong scale through dimensional transmutation. We perturbatively expand the\nenergy through a numerical version of stochastic quantization. In contrast to\nthe first energy coefficients, the high order coefficients are independent on\nthe rank of the model. Technically, they require a sophisticated analysis of\nfinite volume effects and the continuum limit of the discretized model.\nAlthough the individual coefficients do not grow factorially (yet), but rather\ndecrease strongly, the ratio of consecutive coefficients clearly obey the\nrenormalon asymptotics."
    },
    {
        "anchor": "Examining the Low Energy Dynamics of Walking Gauge Theory: We report on an investigation into the low energy dynamics of walking gauge\ntheory. Taking $SU(3)$ Yang Mills with eight flavors of fundamental fermions as\nan example, we discuss the light flavor singlet scalar appearing in the\nspectrum and its implications for low energy physics. We compute the maximal\nisospin $\\pi\\pi$ scattering length at the lightest quark masses yet\ninvestigated for the eight flavor theory. The validity of chiral perturbation\ntheory is assessed, and we discuss motivations for a more extensive effective\nfield theory analysis to be carried out in future work.",
        "positive": "Finite volume analysis on systematics of the derivative expansion in HAL\n  QCD method: We study the convergence of the derivative expansion in HAL QCD method from\nthe finite volume analysis. Employing the (2+1)-flavor lattice QCD data\nobtained at nearly physical light quark masses $(m_\\pi, m_K) \\simeq (146, 525)$\nMeV and the physical charm quark mass, we study two representative systems,\n$\\Omega\\Omega$ and $\\Omega_{ccc}\\Omega_{ccc}$ in the $^1S_0$ channel, where\nboth systems were found to have a shallow bound state in our previous studies.\nThe HAL QCD potentials are determined at the leading-order in the derivative\nexpansion, from which finite-volume eigenmodes are obtained. Utilizing the\neigenmode projection, we find that the correlation functions are dominated by\nthe ground state (first excited state) in the case of $\\Omega\\Omega$\n($\\Omega_{ccc}\\Omega_{ccc}$). In both $\\Omega\\Omega$ and\n$\\Omega_{ccc}\\Omega_{ccc}$, the spectra obtained from eigenmode-projected\ntemporal correlators are found to be consistent with those from the HAL QCD\npotential for both the ground and first excited state. These results show that\nthe derivative expansion is well converged in these systems, and also provide a\nfirst explicit evidence that the HAL QCD method enables us to reliably extract\nthe binding energy of the ground state even from the correlator dominated by\nexcited scattering states."
    },
    {
        "anchor": "Light Meson Distribution Amplitudes: We calculated the first two moments of the light-cone distribution amplitudes\nfor the pseudoscalar mesons ($\\pi$ and $K$) and the longitudinally polarised\nvector mesons ($\\rho$, $K^*$ and $\\phi$) as part of the UKQCD and RBC\ncollaborations' $N_f=2+1$ domain-wall fermion phenomenology programme. These\nquantities were obtained with a good precision and, in particular, the expected\neffects of $SU(3)$-flavour symmetry breaking were observed. Operators were\nrenormalised non-perturbatively and extrapolations to the physical point were\nmade, guided by leading order chiral perturbation theory. The main results\npresented are for two volumes, $16^3\\times 32$ and $24^3\\times 64$, with a\ncommon lattice spacing. Preliminary results for a lattice with a finer lattice\nspacing, $32^3\\times64$, are discussed and a first look is taken at the use of\ntwisted boundary conditions to extract distribution amplitudes.",
        "positive": "Pure Lattice Gauge Theory in the Expanding Universe: Using Monte Carlo methods, I study the thermodynamic properties of Z_2\nAbelian lattice gauge theory in flat, homogeneous, isotropic, expanding\nspacetimes characterized by the scale factor a(t). The presence of the scale\nfactor introduces a spacelike domain wall inside the four dimensional spacetime\nlattice where the phase transition associated with deconfinement occurs. The\nresulting theory appears identical to introducing a time-dependent effective\ncoupling beta_eff, and could serve as a simple model for the electroweak phase\ntransition of the early Universe."
    },
    {
        "anchor": "Coulomb gauge Green functions and Gribov copies in SU(2) lattice gauge\n  theory: We reconsider the lattice measurement of Green functions in Coulomb gauge,\nboth in 2+1 and 3+1 dimensions, using an improved gauge fixing scheme. The\ninfluence of Gribov copies is examined and we find clear indications that Green\nfunctions are more strongly affected than previously assumed, in particular for\nlow momenta. Qualitatively, our improved lattice results in the infra-red\ncompare more favourably with recent continuum calculations in the Hamiltonian\napproach.",
        "positive": "Impact of Dynamical Fermions on QCD Vacuum Structure: We examine how dynamical fermions affect both the UV and infrared structure\nof the QCD vacuum. We consider large $28^3 \\times 96$ lattices from the MILC\ncollaboration, using a gluonic definition of the topological charge density,\nfounded on a new over-improved stout-link smearing algorithm. The algorithm\nreproduces established results from the overlap formalism and is designed to\npreserve nontrivial topological objects including instantons. At short\ndistances we focus on the topological charge correlator, $<q(x) q(0) >$, where\nnegative values at small $x$ reveal a sign-alternating layered structure to the\ntopological-charge density of the QCD vacuum. We find that the magnitudes of\nthe negative dip in the $<q(x)q(0)>$ correlator and the positive $<q(0)^2>$\ncontact term are both increased with the introduction of dynamical fermion\ndegrees of freedom. This is in accord with expectations based on charge\nrenormalization and the vanishing of the topological susceptibility in the\nchiral limit. At large distances we examine the extent to which instanton-like\nobjects are found on the lattice, and how their distributions vary between\nquenched and dynamical gauge fields. We show that dynamical gauge fields\ncontain more instanton-like objects with an average size greater than in the\nquenched vacuum. Finally, we directly visualize the topological charge density\nin order to investigate the effects of dynamical sea-quark degrees of freedom\non topology."
    },
    {
        "anchor": "Finite size and cut-off effects on the Roberge-Weiss transition in\n  $N_\\text{f}=2$ QCD with Staggered fermions: In the absence of a genuine solution to the sign problem, lattice studies at\nimaginary quark chemical potential are an important tool to constrain the QCD\nphase diagram. We calculate the values of the tricritical quark masses in the\nRoberge-Weiss plane, $\\mu=\\imath\\pi T/3$, which separate mass regions with\nchiral and deconfinement phase transitions from the intermediate region, for\nQCD with $N_\\text{f}=2$ unimproved staggered quarks on $N_\\tau=6$ lattices. A\nquantitative measure for the quality of finite size scaling plots is developed,\nwhich significantly reduces the subjective judgement required for fitting. We\nobserve that larger aspect ratios are necessary to unambiguously determine the\norder of the transition than at $\\mu=0$. Comparing with previous results from\n$N_\\tau=4$ we find a $\\sim50$% reduction in the light tricritical pion mass.\nThe heavy tricritical pion mass stays roughly the same, but is too heavy to be\nresolved on $N_\\tau=6$ lattices and thus equally afflicted with cut-off\neffects. Further comparison with other discretizations suggests that current\ncut-off effects on the light critical masses are likely to be larger than\n$\\sim100$%, implying a drastic shrinking of the chiral first-order region to\npossibly zero.",
        "positive": "Status of Complex Langevin: I review the status of the Complex Langevin method, which was invented to\nmake simulations of models with complex action feasible. I discuss the\nmathematical justification of the procedure, as well as its limitations and\nopen questions. Various pragmatic measures for dealing with the existing\nproblems are described. Finally I report on the progress in the application of\nthe method to QCD, with the goal of determining the phase diagram of QCD as a\nfunction of temperature and baryonic chemical potential."
    },
    {
        "anchor": "Lattice QCD Calculations of Parton Physics: In this document, we summarize the status and challenges of calculating\nparton physics in lattice QCD for the US Particle Physics Community Planning\nExercise (a.k.a. \"Snowmass\"). While PDF-moments calculations have been very\nsuccessful and been continuously improved, new methods have been developed to\ncalculate distributions directly in $x$-space. Many recent lattice studies have\nbeen focused on calculating isovector PDFs of the pion and nucleon, learning to\ncontrol systematics associated with excited-state contamination,\nrenormalization and continuum extrapolations, pion-mass and finite-volume\neffects, etc. Although in some cases, the lattice results are already\ncompetitive with experimental data, to reach the level of precision in a wide\nrange of $x$ for unpolarized nucleon PDFs impactful for future collider physics\nremains a challenge, and may require exascale supercomputing power. The new\ntheoretical methods open the door for calculating other partonic observables\nwhich will be the focus of the experimental program in nuclear physics,\nincluding generalized parton distributions and transverse-momentum dependent\nPDFs. A fruitful interplay between experimental data and lattice-QCD\ncalculations will usher in a new era for parton physics and hadron structure.",
        "positive": "Wilson Loop in Classical Lattice Gauge Theory and the Thermal Width of\n  Heavy Quarkonium: We present an estimate for the imaginary part of the recently introduced\nfinite temperature real-time static potential. It can be extracted from the\ntime evolution of the Wilson loop in classical lattice gauge theory. The\nreal-time static potential determines, through a Schroedinger-type equation and\na subsequent Fourier-transform of its solution, the spectral function of heavy\nquarkonium in finite-temperature QCD. We also compare the results of the\nclassical simulations with those of Hard Thermal Loop improved simulations, as\nwell as with analytic expectations based on resummed perturbation theory."
    },
    {
        "anchor": "Chiral Symmetry Restoration and Realisation of the Goldstone Mechanism\n  in the U(1) Gross-Neveu Model at Non-Zero Chemical Potential: We simulate the Gross-Neveu model in 2+1 dimensions at nonzero baryon density\n(chemical potential mu =/= 0). It is possible to formulate this model with a\nreal action and therefore to perform standard hybrid Monte Carlo simulations\nwith mu =/= 0 in the functional measure. We compare the physical observables\nfrom these simulations with simulations using the Glasgow method where the\nvalue of mu in the functional measure is fixed at a value mu_upd. We find that\nthe observables are sensitive to the choice of mu_upd. We consider the\nimplications of our findings for Glasgow method QCD simulations at mu =/= 0. We\ndemonstrate that the realisation of the Goldstone mechanism in the Gross-Neveu\nmodel is fundamentally different from that in QCD. We find that this difference\nexplains why there is an unphysical transition in QCD simulations at mu =/= 0\nassociated with the pion mass scale whereas the transition in the Gross-Neveu\nmodel occurs at a larger mass scale and is therefore consistent with\ntheoretical predictions. We note classes of theories which are exceptions to\nthe Vafa-Witten theorem which permit the possibility of formation of baryon\nnumber violating diquark condensates.",
        "positive": "Can nonlocal Dirac operators be topologically proper ?: By examining the analyticity of a sequence of topologically-proper lattice\nDirac operators, we show that they tend to a nonlocal Dirac operator. This\nimplies that a nonlocal lattice Dirac operator can have exact zero modes\nsatisfying the Atiyah-Singer index theorem, in gauge backgrounds with nonzero\ntopological charge."
    },
    {
        "anchor": "Glueballs in charmonia radiative decays: Scalar \\cite{scalar_paper} and tensor \\cite{tensor_paper} glueballs created\nin $J/\\psi$ radiative decays are studied in quenched lattice QCD. Using two\nanisotropic lattices to approach the continuum limit, we compute the relevant\nform factors responsible for the decay rates for $J/\\psi\\rightarrow\\gamma\nG_{0^{++}}$ and $J/\\psi\\rightarrow\\gamma G_{2^{++}}$.\n  Comparing with the existing experimental data, it is argued that $f_0(1710)$\nis a favorable candidate for scalar glueball. The decay rate for\n$J/\\psi\\rightarrow\\gamma G_{2^{++}}$ is found to be quite substantial. A\ncomprehensive search in the tensor channel on BESIII is therefore suggested.",
        "positive": "A novel scheme for the wave function renormalization of the composite\n  operators: We propose a novel renormalization scheme for the hadronic operators. The\nrenormalization factor of the operator in this scheme is normalized by the\ncorrelation function at tree level in coordinate space. If we focus on the\npseudo scalar operator, then its renormalization factor is related to the mass\nrenormalization factor of the fermion through the partially conserved\naxial-vector current (PCAC) relation. Using the renormalization factor for the\npseudo scalar operator in our scheme, we obtain the mass anomalous dimension of\nthe SU(3) gauge theory coupled to N_f=12 massless fundamental fermions, which\nhas an infrared fixed point (IRFP). The mass anomalous dimension at the IRFP is\nestimated as gamma_m^*= 0.044_{-0.024}^{+0.025} (stat.)_{-0.032}^{+0.057}\n(syst.)."
    },
    {
        "anchor": "Testing the Quasi-temporal Gauge on the Lattice: We investigate the viability of the quasi-temporal gauge on the lattice. This\nis a complete gauge fixing condition that can be implemented on the lattice at\na very low computational cost. As a test case, using the Clover action, we have\nevaluated the (gauge invariant) renormalisation constant of the non-singlet\naxial current, using Ward identities extracted from quark states. Our result is\nin reasonable but not complete agreement with previous values obtained from\nWard identities both on hadronic states and on quark states in the Landau\ngauge. We observe large fluctuations due to lattice Gribov copies. The\ninfluence of finite volume effects is expected to be non-negligible in the case\nwe are considering.",
        "positive": "Conserved currents for Mobius Domain Wall Fermions: We derive the exactly conserved vector, and almost conserved axial currents\nfor rational approximations to the overlap operator with a general Mobius\nkernel. The approach maintains manifest Hermiticity, and allows matrix elements\nof the currents to be constructed at no extra cost after solution of the usual\n5d system of equations, similar to the original approach of Furman and Shamir\nfor domain wall Fermions."
    },
    {
        "anchor": "Extrapolation Methods for the Dirac Inverter in Hybrid Monte Carlo: In Hybrid Monte Carlo(HMC) simulations for full QCD, the gauge fields evolve\nsmoothly as a function of Molecular Dynamics (MD) time. Thus we investigate\nimproved methods of estimating the trial solutions to the Dirac propagator as\nsuperpositions of the solutions in the recent past. So far our best\nextrapolation method reduces the number of Conjugate Gradient iterations per\nunit MD time by about a factor of 4. Further improvements should be forthcoming\nas we further exploit the information of past trajectories.",
        "positive": "Renormalization of Null Wilson Lines in EQCD: Radiation and energy loss of a light, high-energy parton in a perturbative\nQuark-Gluon Plasma is controlled by transverse momentum exchange. The\ntroublesome infrared contributions to transverse momentum exchange can be\ncomputed on the lattice using dimensional reduction to EQCD. However a novel\nextended operator, the Null Wilson Line of EQCD, is involved. We compute the\nrenormalization properties of this object's lattice implementation to\nnext-to-leading order, which should facilitate its efficient calculation on the\nlattice."
    },
    {
        "anchor": "Octet baryon masses and sigma terms from an SU(3) chiral extrapolation: We report an analysis of the impressive new lattice simulation results for\noctet baryon masses in 2+1-flavor QCD. The analysis is based on a low order\nexpansion about the chiral SU(3) limit in which the symmetry breaking arises\nfrom terms linear in the quark masses plus the variation of the Goldstone boson\nmasses in the leading chiral loops. The baryon masses evaluated at the physical\nlight quark masses are in remarkable agreement with the experimental values,\nwith a model dependence considerably smaller than the rather small statistical\nuncertainty. From the mass formulae one can evaluate the sigma commutators for\nall octet baryons. This yields an accurate value for the pion-nucleon sigma\ncommutator. It also yields the first determination of the strangeness sigma\nterm based on 2+1-flavor lattice QCD and, in general, the sigma commutators\nprovide a resolution to the difficult issue of fine-tuning the strange quark\nmass.",
        "positive": "Symmetry restoration at high-temperature in two-color and two-flavor\n  lattice gauge theories: We consider the $SU(2)$ gauge theory with $N_f=2$ flavors of Dirac\nfundamental fermions. We study the high-temperature behavior of the spectra of\nmesons, discretizing the theory on anisotropic lattices, and measuring the\ntwo-point correlation functions in the temporal direction as well as screening\nmasses in various channels. We identify the (pseudo-)critical temperature as\nthe temperature at which the susceptibility associated with the Polyakov loop\nhas a maximum. At high temperature both the spin-1 and spin-0 sectors of the\nlight meson spectra exhibit enhanced symmetry properties, indicating the\nrestoration of both the global $SU(4)$ and the axial $U(1)_A$ symmetries of the\nmodel."
    },
    {
        "anchor": "Searching for a CEP signal with lattice QCD simulations: We discuss the reliability of available methods to constrain the location of\nthe QCD critical endpoint with lattice simulations. In particular we calculate\nthe baryon fluctuations up to $\\chi^B_8$ using simulations at imaginary\nchemical potentials. We argue that they contain no hint of criticality.",
        "positive": "Nucleon form factors with 2+1 flavor dynamical domain-wall fermions: We report our numerical lattice QCD calculations of the isovector nucleon\nform factors for the vector and axialvector currents: the vector, induced\ntensor, axialvector, and induced pseudoscalar form factors. The calculation is\ncarried out with the gauge configurations generated with N_f=2+1 dynamical\ndomain wall fermions and Iwasaki gauge actions at beta = 2.13, corresponding to\na cutoff 1/a = 1.73 GeV, and a spatial volume of (2.7 fm)^3. The up and down\nquark masses are varied so the pion mass lies between 0.33 and 0.67 GeV while\nthe strange quark mass is about 12% heavier than the physical one. We calculate\nthe form factors in the range of momentum transfers, 0.2 < q^2 < 0.75 GeV^2.\nThe vector and induced tensor form factors are well described by the\nconventional dipole forms and result in significant underestimation of the\nDirac and Pauli mean-squared radii and the anomalous magnetic moment compared\nto the respective experimental values. We show that the axialvector form factor\nis significantly affected by the finite spatial volume of the lattice. In\nparticular in the axial charge, g_A/g_V, the finite volume effect scales with a\nsingle dimensionless quantity, m_pi L, the product of the calculated pion mass\nand the spatial lattice extent. Our results indicate that for this quantity,\nm_pi L > 6 is required to ensure that finite volume effects are below 1%."
    },
    {
        "anchor": "Light flavor-singlet scalars and walking signals in $N_f=8$ QCD on the\n  lattice: Based on the highly improved staggered quark action, we perform lattice\nsimulations of $N_f=8$ QCD and confirm our previous observation of a\nflavor-singlet scalar meson (denoted as $\\sigma$) as light as the pion and\nvarious \"walking signals\" through low-lying spectra, with higher statistics,\nsmaller fermion masses $m_f$, and larger volumes. We measure $M_\\pi$, $F_\\pi$,\n$M_\\rho$, $M_{a_0}$, $M_{a_1}$, $M_{b_1}$, $M_N$, $M_\\sigma$, $F_\\sigma$,\n$\\langle \\bar{\\psi} \\psi\\rangle$ (both directly and through the GMOR relation),\nand the string tension. The data are consistent with the spontaneously broken\nphase of the chiral symmetry, in agreement with the previous results: ratios of\nthe quantities to $M_\\pi$ monotonically increase in the smaller $m_f$ region\ntowards the chiral limit similarly to $N_f=4$ QCD, in sharp contrast to\n$N_f=12$ QCD where the ratios become flattened. The hyperscaling relation holds\nwith roughly a universal value of the anomalous dimension, $\\gamma_m \\simeq 1$,\nwith a notable exception of $M_\\pi$ with $\\gamma_m \\simeq 0.6$ as in the\nprevious results. This is a salient feature (\"walking signal\") of $N_f=8$,\nunlike either $N_f=4$ which has no hyperscaling relation at all, or $N_f=12$\nQCD which exhibits universal hyperscaling. We further confirm the previous\nobservation of the light $\\sigma$ with mass comparable to the pion in the\nstudied $m_f$ region. In a chiral limit extrapolation of the $\\sigma$ mass\nusing the dilaton chiral perturbation theory and also using the simple linear\nfit, we find the value consistent with the 125 GeV Higgs boson within errors.\nOur results suggest that the theory could be a good candidate for walking\ntechnicolor model, having anomalous dimension $\\gamma_m \\simeq 1$ and a light\nflavor-singlet scalar meson as a technidilaton, which can be identified with\nthe 125 GeV composite Higgs in $N_f=8$ one-family model.",
        "positive": "Restoration of Chiral Symmetry from a Boundary: The imposition of Dirichlet boundary conditions in lattice computations\nobstructs the formation of a chiral condensate. We use chiral perturbation\ntheory and meson models to address the effect of a Dirichlet boundary on chiral\nsymmetry breaking. While pions are the longest-range modes in QCD, the\nrestoration of chiral symmetry due to a boundary is shown not to depend upon\nthe pion Compton wavelength but rather on that of the sigma meson. Power-law\nfinite size corrections are exposed, and require prohibitively large lattices\nto overcome. We further speculate on the frustration of the chiral condensate\nfor the case of confinement to the surface of a sphere."
    },
    {
        "anchor": "Taylor- and fugacity expansion for the effective center model of QCD at\n  finite density: Using the effective center model of QCD we test series expansions for finite\nchemical potential $\\mu$. In particular we study two variants of Taylor\nexpansion as well as the fugacity series. The effective center model has a dual\nrepresentation where the sign problem is absent and reliable Monte Carlo\nsimulations are possible at arbitrary $\\mu$. We use the results from the dual\nsimulation as reference data to assess the Taylor- and fugacity series\napproaches. We find that for most of parameter space fugacity expansion is the\nbest (but also numerically most expensive) choice for reproducing the dual\nsimulation results, while conventional Taylor expansion is reliable only for\nvery small $\\mu$. We also discuss the results of a modified Taylor expansion in\n$e^{\\pm \\mu} - 1 $ which at the same numerical effort clearly outperforms the\nconventional Taylor series.",
        "positive": "Tuning HMC parameters with gradients: We investigate the effectiveness of tuning HMC parameters using information\nfrom the gradients of the HMC acceptance probability with respect to the\nparameters. In particular, the optimization of the trajectory length and\nparameters for higher order integrators will be studied in the context of pure\ngauge and dynamical fermion actions."
    },
    {
        "anchor": "Chiral random matrix theory for staggered fermions: We present a completed random matrix theory for staggered fermions which\nincorporates all taste symmetry breaking terms at their leading order from the\nstaggered chiral Lagrangian. This is an extension of previous work which only\nincluded some of the taste breaking terms. We will also discuss the effects of\ntaste symmetry breaking on the eigenvalues in the weak and strong taste\nbreaking limits, and compare with some results from lattice simulations.",
        "positive": "Construction of staples in lattice gauge theory on a parallel computer: We propose a simple method to construct staples in lattice gauge theory with\nWilson action on a parallel computer. This method can be applicable to any\ndimensional system and to any dimensional division without difficulty.\nFurthermore this requires rather small working area to realize gauge simulation\non a parallel computer."
    },
    {
        "anchor": "Universality crossover between chiral random matrix ensembles and\n  twisted SU(2) lattice Dirac spectra: Motivated by the statistical fluctuation of Dirac spectrum of QCD-like\ntheories subjected to (pseudo)reality-violating perturbations and in the\nepsilon-regime, we compute the smallest eigenvalue distribution and the level\nspacing distribution of chiral and non-chiral parametric random matrix\nensembles of Dyson-Mehta-Pandey type. To this end we employ the Nystrom method\nto numerically evaluate the Fredholm Pfaffian of the integral kernel for the\nchG(O,S)E-chGUE and G(O,S)E-GUE crossover. We confirm the validity and\nuniversality of our results by comparing them with several lattice models,\nnamely fundamental and adjoint staggered Dirac spectra of SU(2) quenched\nlattice gauge theory under the twisted boundary condition (imaginary chemical\npotential) or perturbed by phase noise. Both in the zero-virtuality region and\nin the spectral bulk, excellent one-parameter fitting is achieved already on a\nsmall 4^4 lattice. Anticipated scaling of the fitting parameter with the\ntwisting phase, mean level spacing, and the system size allows for precise\ndetermination of the pion decay (diffusion) constant F in the low-energy\neffective Lagrangian.",
        "positive": "Comparison of complex Langevin and mean field methods applied to\n  effective Polyakov line models: Effective Polyakov line models, derived from SU(3) gauge-matter systems at\nfinite chemical potential, have a sign problem. In this article I solve two\nsuch models, derived from SU(3) gauge-Higgs and heavy quark theories by the\nrelative weights method, over a range of chemical potentials where the sign\nproblem is severe. Two values of the gauge-Higgs coupling are considered,\ncorresponding to a heavier and a lighter scalar particle. Each model is solved\nvia the complex Langevin method, following the approach of Aarts and James, and\nalso by a mean field technique. It is shown that where the results of mean\nfield and complex Langevin agree, they agree almost perfectly. Where the\nresults of the two methods diverge, it is found that the complex Langevin\nevolution has a branch cut crossing problem, associated with a logarithm in the\naction, that was pointed out by Mollgaard and Splittorff."
    },
    {
        "anchor": "Multi GPU Performance of Conjugate Gradient Algorithm with Staggered\n  Fermions: We report results of the performance test of GPUs obtained using the\nconjugate gradient (CG) algorithm for staggered fermions on the MILC fine\nlattice ($28^3 \\times 96$). We use GPUs of nVIDIA GTX 295 model for the test.\nWhen we turn off the MPI communication and use only a single GPU, the\nperformance is 35 giga flops in double precision, which corresponds to 47% of\nthe peak. When we turn on the MPI communication and use multi-GPUs, the\nperformance is reduced down to 12.3 giga flops. The data transfer through the\ninfiniband network and PCI-E bus I/O is a main bottle neck. We suggest two\npotential solutions of how to optimize the data transfer.",
        "positive": "Rediscovery of Numerical L\u00fcscher's Formula from the Neural Network: We present that by predicting the spectrum in discrete space from the phase\nshift in continuous space, the neural network can remarkably reproduce the\nnumerical L\\\"uscher's formula to a high precision. The model-independent\nproperty of the L\\\"uscher's formula is naturally realized by the\ngeneralizability of the neural network. This exhibits the great potential of\nthe neural network to extract model-independent relation between\nmodel-dependent quantities, and this data-driven approach could greatly\nfacilitate the discovery of the physical principles underneath the intricate\ndata."
    },
    {
        "anchor": "Lattice QCD Determination of $g_A$: The nucleon axial coupling, $g_A$, is a fundamental property of protons and\nneutrons, dictating the strength with which the weak axial current of the\nStandard Model couples to nucleons, and hence, the lifetime of a free neutron.\nThe prominence of $g_A$ in nuclear physics has made it a benchmark quantity\nwith which to calibrate lattice QCD calculations of nucleon structure and more\ncomplex calculations of electroweak matrix elements in one and few nucleon\nsystems. There were a number of significant challenges in determining $g_A$,\nnotably the notorious exponentially-bad signal-to-noise problem and the\nrequirement for hundreds of thousands of stochastic samples, that rendered this\ngoal more difficult to obtain than originally thought.\n  I will describe the use of an unconventional computation method, coupled with\n\"ludicrously'\" fast GPU code, access to publicly available lattice QCD\nconfigurations from MILC and access to leadership computing that have allowed\nthese challenges to be overcome resulting in a determination of $g_A$ with 1%\nprecision and all sources of systematic uncertainty controlled. I will discuss\nthe implications of these results for the convergence of $SU(2)$ Chiral\nPerturbation theory for nucleons, as well as prospects for further improvements\nto $g_A$ (sub-percent precision, for which we have preliminary results) which\nis part of a more comprehensive application of lattice QCD to nuclear physics.\nThis is particularly exciting in light of the new CORAL supercomputers coming\nonline, Sierra and Summit, for which our lattice QCD codes achieve a\nmachine-to-machine speed up over Titan of an order of magnitude.",
        "positive": "Dynamic critical behavior of the Swendsen--Wang Algorithm for the\n  three-dimensional Ising model: We have performed a high-precision Monte Carlo study of the dynamic critical\nbehavior of the Swendsen-Wang algorithm for the three-dimensional Ising model\nat the critical point. For the dynamic critical exponents associated to the\nintegrated autocorrelation times of the \"energy-like\" observables, we find\nz_{int,N} = z_{int,E} = z_{int,E'} = 0.459 +- 0.005 +- 0.025, where the first\nerror bar represents statistical error (68% confidence interval) and the second\nerror bar represents possible systematic error due to corrections to scaling\n(68% subjective confidence interval). For the \"susceptibility-like\"\nobservables, we find z_{int,M^2} = z_{int,S_2} = 0.443 +- 0.005 +- 0.030. For\nthe dynamic critical exponent associated to the exponential autocorrelation\ntime, we find z_{exp} \\approx 0.481. Our data are consistent with the\nCoddington-Baillie conjecture z_{SW} = \\beta/\\nu \\approx 0.5183, especially if\nit is interpreted as referring to z_{exp}."
    },
    {
        "anchor": "Correlation functions of the energy-momentum tensor in SU(2) gauge\n  theory at finite temperature: We calculate correlation functions of the energy-momentum tensor in the\nvicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge\ntheory and discuss their critical behavior in the vicinity of the second order\ndeconfinement transition. We show that correlation functions of the trace of\nthe energy momentum tensor diverge uniformly at the critical point in\nproportion to the specific heat singularity. Correlation functions of the\npressure, on the other hand, stay finite at the critical point. We discuss the\nconsequences of these findings for the analysis of transport coefficients, in\nparticular the bulk viscosity, in the vicinity of a second order phase\ntransition point.",
        "positive": "Hyperon vector coupling f_1(0) from 2+1 flavor lattice QCD: We present results for the hyperon vector form factor f_1 for $\\Xi^0\n\\rightarrow \\Sigma^+ l\\bar{\\nu}$ and $\\Sigma^- \\rightarrow n l\\bar{\\nu}$\nsemileptonic decays from dynamical lattice QCD with domain-wall quarks.\nSimulations are performed on the 2+1 flavor gauge configurations generated by\nthe RBC and UKQCD Collaborations with a lattice cutoff of 1/a = 1.7 GeV. Our\npreliminary results, which are calculated at the lightest sea quark mass (pion\nmass down to approximately 330 MeV), show that a sign of the second-order\ncorrection of SU(3) breaking on hyperon vector coupling f_1(0) is likely\nnegative."
    },
    {
        "anchor": "On the effect of excited states in lattice calculations of the nucleon\n  axial charge: Excited-state contamination is one of the dominant uncertainties in lattice\ncalculations of the nucleon axial-charge, $g_A$. Recently published results in\nleading-order chiral perturbation theory (ChPT) predict the excited-state\ncontamination to be independent of the nucleon interpolator and positive.\nHowever, empirical results from numerical lattice calculations show negative\ncontamination (downward curvature), indicating that present-day calculations\nare not in the regime where the leading-order ChPT predictions apply. In this\npaper we show that, under plausible assumptions, one can reproduce the behavior\nof lattice correlators by taking into account final-state $N \\pi$ interactions,\nin particular the effect of the Roper resonance, and by postulating a sign\nchange in the infinite-volume $N \\to N \\pi$ axial-vector transition amplitude.",
        "positive": "Dual $Z_2$ Lattice Gauge Theory of the 3D Ising Model with both Nearest-\n  and Next-Nearest-Neighbor Couplings: It is known that the normal three-dimensional (3D) Ising model on a cubic\nlattice is dual to the Wegner's 3D $Z_2$ lattice gauge theory. Here we find an\nunusual $Z_2$ lattice gauge theory which is dual to the 3D Ising model with not\nonly nearest-neighbor (nn) coupling, but also next-nearest-neighbor (nnn)\ncoupling. Our gauge theory has on each edge four $Z_2$ variables that have\nproduct $+1$, each located on a vector perpendicular to the edge. The nn\ncoupling in the Ising model maps to the plaquette term in the gauge theory\nwhere the four variables multiplied have their vectors pointing inward, while\nthe nnn coupling maps to the coupling between the $Z_2$ variables on nearby\nvectors on each edge in the gauge theory. A Wilson loop observable in the gauge\ntheory depends on a framing of a loop, and maps to a surface of flipped-sign nn\nand nnn couplings in the Ising model. Further numerical simulations could be\nmade to explore the universality at the phase transition."
    },
    {
        "anchor": "Perturbative $O(\u03b1_s a)$ matching in static heavy and domain-wall\n  light quark system: We discuss the perturbative $O(\\alpha_s a)$ matching in the static heavy and\ndomain-wall light quark system. The gluon action is the Iwasaki action and the\nlink smearing is performed in the static heavy action. The chiral symmetry of\nthe light quark realized by using the domain-wall fermion formulation does not\nprohibit the mixing of the operators at $O(a)$. The application of $O(a)$\nimprovement to the actual data shows that the B meson decay constant $f_B$, the\nmatrix elements ${\\cal M}_B$ and the B parameter $B_B$ have non-negligible\neffects, while the effect on the SU(3) breaking ratio $\\xi$ is small.",
        "positive": "Spectroscopy, Equation Of State And Monopole Percolation In Lattice QED\n  With Two Flavors: Non-compact lattice QED with two flavors of light dynamical quarks is\nsimulated on $16^4$ lattices, and the chiral condensate, monopole density and\nsusceptibility and the meson masses are measured. Data from relatively high\nstatistics runs at relatively small bare fermion masses of 0.005, 0.01, 0.02\nand 0.03 (lattice units) are presented. Three independent methods of data\nanalysis indicate that the critical point occurs at $\\beta =0.225(5)$ and that\nthe monopole condensation and chiral symmetry breaking transitions are\ncoincident. The monopole condensation data satisfies finite size scaling\nhypotheses with critical indices compatible with four dimensional percolation.\nThe best chiral equation of state fit produces critical exponents\n($\\delta=2.31$, $\\beta_{mag}=0.763$) which deviate significantly from mean\nfield expectations. Data for the ratio of the sigma to pion masses produces an\nestimate of the critical index $\\delta$ in good agreement with chiral\ncondensate measurements. In the strong coupling phase the ratio of the meson\nmasses are $M_\\sigma^2/M_\\rho^2\\approx 0.35$, $M_{A_1}^2/M_\\rho^2\\approx 1.4$\nand $M_\\pi^2/M_\\rho^2\\approx 0.0$, while on the weak coupling side of the\ntransition $M_\\pi^2/M_\\rho^2\\approx 1.0$, $M_{A_1}^2/M_\\rho^2\\approx 1.0$,\nindicating the restoration of chiral symmetry.\\footnote{$\\,^{}$}{August 1992}"
    },
    {
        "anchor": "Toward Precision Measurement of $B_K$ with Quenched Kogut-Susskind\n  Quarks: We present a status report of our ongoing effort toward a precision\ndetermination of the kaon $B$ parameter with the Kogut-Susskind quark action in\nquenched QCD. Results for $B_K$ so far accumulated at $\\beta =5.85$, 5.93, 6.0\nand 6.2 corresponding to $a^{-1}=1.3-2.6$ GeV do not exhibit the theoretically\nexpected $O(a^2)$ behavior, but are apparently more consistent with an $O(a)$\nbehavior.",
        "positive": "Parallel Tempered Metadynamics: Overcoming potential barriers without\n  surfing or tunneling: At fine lattice spacings, Markov chain Monte Carlo simulations of QCD and\nother gauge theories are plagued by slow (topological) modes that give rise to\nlarge autocorrelation times. These, in turn, lead to statistical and systematic\nerrors that are difficult to estimate. Here, we demonstrate that for a relevant\nset of parameters considered, Metadynamics can be used to reduce the\nautocorrelation times of topological quantities in 4-dimensional SU(3) gauge\ntheory by at least two orders of magnitude compared to conventional update\nalgorithms. However, compared to local update algorithms and the Hybrid Monte\nCarlo algorithm, the computational overhead is significant, and the required\nreweighting procedure may considerably reduce the effective sample size. To\ndeal with the latter problem, we propose modifications to the Metadynamics bias\npotential and the combination of Metadynamics with parallel tempering. We test\nthe new algorithm in 4-dimensional SU(3) gauge theory and find, that it can\nachieve topological unfreezing without compromising the effective sample size.\nPreliminary scaling tests in 2-dimensional U(1) gauge theory show these\nmodifications lead to improvements of more than an order of magnitude compared\nto standard Metadynamics, and an improved scaling of autocorrelation times with\nthe lattice spacing compared to standard update algorithms."
    },
    {
        "anchor": "$V_{cs}$ determination from $D \\to{}K \\ell \u03bd$: Semileptonic $D \\to{}K \\ell \\nu$ decays provide one angle of attack to get at\nthe CKM matrix element $V_{cs}$, complementary to the study of leptonic $D_s$\ndecays. Here, HPQCD present the results of a recently published, improved\ndetermination of $V_{cs}$. We discuss a new, precise determination of $D\\to K$\nscalar and vector form factors from a lattice calculation on eight different\n$N_f=2+1+1$ MILC gluon field ensembles using the HISQ action, including three\nwith physical light quark masses. When combined with experimental results, we\nare able to extract $|V_{cs}|=0.9663(80)$ to a sub percent level of precision\nfor the first time. This is achieved using three different methods, which each\ncombine our form factors with different sets of experimental results in\ndifferent ways, with the results in very good agreement. Our primary method is\nto use $q^2$-binned data for the differential decay rate, but we also calculate\n$V_{cs}$ from the total branching fraction and from the value $|V_{cs}|f_+(0)$,\nwhich is also quoted by some experiments.",
        "positive": "Elastic and resonance structures of the nucleon from hadronic tensor in\n  lattice QCD: implications for neutrino-nucleon scattering and hadron physics: Understanding the transitions of nucleons into various resonance structures\nthrough electromagnetic interactions plays a pivotal role in advancing our\ncomprehension of the strong interactions within the domain of quark\nconfinement. Furthermore, gaining precise insights into the elastic and\nresonance structures of nucleons is indispensable for deciphering the physics\nfrom neutrino-nucleus scattering cross sections experimental data, which remain\ntheoretically challenging, even in the context of neutrino-nucleon interactions\nwhose profound understanding is imperative for the neutrino oscillation\nexperiments. One promising avenue involves the direct evaluation of the\nlepton-nucleon scattering cross sections across quasi-elastic, resonance,\nshallow-inelastic, and deep inelastic regions, which can be achieved through\nthe hadronic tensor formalism in lattice QCD. In this work, we present the\ndetermination of the nucleon's Sachs electric form factor using the hadronic\ntensor formalism and verify that it is consistent with that from the\nconventional three-point function calculation. We additionally obtain the\ntransition form factor from the nucleon to its first radial excited state\nwithin a finite volume. Consequently, we identify the latter with the\nnucleon-to-Roper transition form factor $G_E^*(Q^2)$, determine the\ncorresponding longitudinal helicity amplitude $S_{1/2}(Q^2)$ and compare our\nfindings with experimental measurements, for the first time using the hadronic\ntensor formalism. The limitations and systematic improvements of the approach\nare also discussed."
    },
    {
        "anchor": "Towards a controlled study of the QCD critical point: The phase diagram of QCD, as a function of temperature T and quark chemical\npotential mu, may contain a critical point (mu_E,T_E) whose non-perturbative\nnature makes it a natural object of lattice studies. However, the sign problem\nprevents the application of standard Monte Carlo techniques at non-zero baryon\ndensity. We have been pursuing an approach free of the sign problem, where the\nchemical potential is taken as imaginary and the results are Taylor-expanded in\nmu/T about mu=0, then analytically continued to real mu.\n  Within this approach we have determined the sensitivity of the critical\nchemical potential mu_E to the quark mass, d(\\mu_E)^2/dm_q|_{\\mu_E=0}. Our\nstudy indicates that the critical point moves to {\\em smaller} chemical\npotential as the quark mass {\\em increases}. This finding, contrary to common\nwisdom, implies that the deconfinement crossover, which takes place in QCD at\nmu=0 when the temperature is raised, will remain a crossover in the mu-region\nwhere our Taylor expansion can be trusted. If this result, obtained on a coarse\nlattice, is confirmed by simulations on finer lattices now in progress, then we\npredict that no {\\em chiral} critical point will be found for mu_B \\lesssim 500\nMeV, unless the phase diagram contains additional transitions.",
        "positive": "Chiral Corrections to Nucleon Two- and Three-Point Correlation Functions: We consider multi-particle contributions to nucleon two- and three-point\nfunctions from the perspective of chiral dynamics. Lattice nucleon\ninterpolating operators, which have definite chiral transformation properties,\ncan be mapped into chiral perturbation theory. Using the most common of such\noperators, we determine pion-nucleon and pion-delta couplings to nucleon two-\nand three-point correlation functions at leading order in the low-energy\nexpansion. The couplings of pions to nucleons and deltas in two-point functions\nare consistent with simple phase-space considerations, in accordance with the\nLehmann spectral representation. An argument based on available phase space on\na torus is utilized to derive the scaling of multiple-pion couplings. While\nmulti-pion states are indeed suppressed, this suppression scales differently\nwith particle number compared to that in infinite volume. For nucleon\nthree-point correlation functions, we investigate the axial-vector current at\nvanishing momentum transfer. The effect of pion-nucleon and pion-delta states\non the extraction of the nucleon axial charge is assessed. We show that\ncouplings to finite volume multi-particle states could potentially lead to\noverestimation of the axial charge. Hence pion-nucleon excited states cannot\nexplain the trend seen in lattice QCD calculations of the nucleon axial charge."
    },
    {
        "anchor": "Lattice simulation of ultracold atomic Bose-Fermi mixtures: Bose-Fermi mixtures have been recently realized and invesitigated in\nultracold atomic experiments. We formulate quantum Monte Carlo simulation of\nBose-Fermi mixtures on the (3+1)-dimensional lattice. As its first application,\nwe analyze the boson-fermion pair correlation and the phase diagram of the\nBose-Einstein condensation.",
        "positive": "The Evolution of Lattice Field Theory: a Statistical Study: Researchers working in lattice field theory constitute an established\ncommunity since the early 1990s, and around the same time the online\nopen-access e-print repository arXiv was created. The fact that this field has\na specific arXiv section, hep-lat, provides a unique opportunity for a\nstatistical study of its evolution over the last three decades. We present data\nfor the number of entries, $E$, published papers, $P$, and citations, $C$, in\ntotal and separated by nations. We compare them to 6 other arXiv sections, and\nto socio-economic indices of the nations involved, namely the Gross Domestic\nProduct (GDP) and the Education Index (EI). We present rankings, which are\nbased either on the Hirsch Index $H$, or on the linear combination $\\Sigma = E\n+ P + 0.05 C$. We consider both extensive and intensive national statistics,\ni.e. absolute and relative to the population or to the GDP."
    },
    {
        "anchor": "Lattice calculations of the spectroscopy of baryons with broken flavor\n  SU(3) symmetry and 3, 5, or 7 colors: Lattice Monte Carlo calculations of baryon spectroscopy in gauge groups\nSU(N), N=3, 5, 7, are presented. The quenched valence fermions come in three\nflavors, two degenerate mass ones and a third heavier flavor. The data shows\nstriking regularities reminiscent of the real-world case of N=3: higher angular\nmomentum states lie higher in mass, and Sigma-like states lie higher than\nLambda-like ones. These simple regularities are reasonably well described by\n1/N expansions.",
        "positive": "$T_{cc}^{+}(3875)$ relevant $DD^*$ scattering from $N_f=2$ lattice QCD: The $S$-wave $DD^*$ scattering in the isospin $I=0,1$ channels is studied in\n$N_f=2$ lattice QCD at $m_\\pi\\approx 350$ MeV. It is observed that the $DD^*$\ninteraction is repulsive in the $I=1$ channel when the $DD^*$ energy is near\nthe $DD^*$ threshold. In contrast, the $DD^*$ interaction in the $I=0$ channel\nis definitely attractive in a wide range of the $DD^*$ energy. This is\nconsistent with the isospin assignment $I=0$ for $T_{cc}^+(3875)$. By analyzing\nthe components of the $DD^*$ correlation functions, it turns out that the quark\ndiagram responsible for the different properties of $I=0,1$ $DD^*$ interactions\ncan be understood as the charged $\\rho$ meson exchange effect. This observation\nprovides direct information on the internal dynamics of $T_{cc}^+(3875)$."
    },
    {
        "anchor": "Separating the scales of confinement and chiral-symmetry breaking in\n  lattice QCD with fundamental quarks: Suggested holographic duals of QCD, based on AdS/CFT duality, predict that\none should be able to vary the scales of colour confinement and chiral-symmetry\nbreaking independently. Furthermore they suggest that such independent\nvariation of scales can be achieved by the inclusion of extra 4-fermion\ninteractions in QCD. We simulate lattice QCD with such extra 4-fermion terms at\nfinite temperatures and show that for strong enough 4-fermion couplings the\ndeconfinement transition occurs at a lower temperature than the chiral-symmetry\nrestoration transition. Moreover the separation of these transitions depends on\nthe size of the 4-fermion coupling, confirming the predictions from the\nproposed holographic dual of QCD.",
        "positive": "A Lattice Calculation of Parton Distributions: We present results for the $x$ dependence of the unpolarized, helicity, and\ntransversity isovector quark distributions in the proton using lattice QCD,\nemploying the method of quasi-distributions proposed by Ji in 2013. Compared to\na previous calculation by us, the errors are reduced by a factor of about 2.5.\nMoreover, we present our first results for the polarized sector of the proton,\nwhich indicate an asymmetry in the proton sea in favor of the $u$ antiquarks\nfor the case of helicity distributions, and an asymmetry in favor of the $d$\nantiquarks for the case of transversity distributions."
    },
    {
        "anchor": "Modeling the Gluon Propagator in Landau Gauge: Lattice Estimates of Pole\n  Masses and Dimension-Two Condensates: We present an analytic description of numerical results for the Landau-gauge\nSU(2) gluon propagator D(p^2), obtained from lattice simulations (in the\nscaling region) for the largest lattice sizes to date, in d = 2, 3 and 4\nspace-time dimensions. Fits to the gluon data in 3d and in 4d show very good\nagreement with the tree-level prediction of the Refined Gribov-Zwanziger (RGZ)\nframework, supporting a massive behavior for D(p^2) in the infrared limit. In\nparticular, we investigate the propagator's pole structure and provide\nestimates of the dynamical mass scales that can be associated with\ndimension-two condensates in the theory. In the 2d case, fitting the data\nrequires a non-integer power of the momentum p in the numerator of the\nexpression for D(p^2). In this case, an infinite-volume-limit extrapolation\ngives D(0) = 0. Our analysis suggests that this result is related to a\nparticular symmetry in the complex-pole structure of the propagator and not to\npurely imaginary poles, as would be expected in the original Gribov-Zwanziger\nscenario.",
        "positive": "Gauge covariant neural network for 4 dimensional non-abelian gauge\n  theory: Quantum-Chromo dynamics (QCD) is a fundamental theory for quarks and gluons,\nwhich describes both the sub-atomic world and the history of our universe. The\nsimulation for QCD on a lattice (lattice QCD) is one of the most challenging\ncomputational tasks. Recently, machine-learning techniques have been applied to\nsolve various problems in lattice QCD. We propose gauge covariant neural\nnetworks and their training rule for lattice QCD, which can treat realistic\nquarks and gluons in four dimensions. We find that the smearing procedure can\nbe regarded as extended versions of residual neural networks with fixed\nparameters. To show the applicability of our neural networks, we develop the\nself-learning hybrid Monte-Carlo for two-color QCD, where results are\nconsistent with the results of the Hybrid Monte Carlo."
    },
    {
        "anchor": "Sea Quarks Contribution to the Nucleon Magnetic Moment and Charge Radius\n  at the Physical Point: We report a comprehensive analysis of the light and strange disconnected-sea\nquarks contribution to the nucleon magnetic moment, charge radius, and the\nelectric and magnetic form factors. The lattice QCD calculation includes\nensembles across several lattice volumes and lattice spacings with one of the\nensembles at the physical pion mass. We adopt a model-independent extrapolation\nof the nucleon magnetic moment and the charge radius. We have performed a\nsimultaneous chiral, infinite volume, and continuum extrapolation in a global\nfit to calculate results in the continuum limit. We find that the combined\nlight and strange disconnected-sea quarks contribution to the nucleon magnetic\nmoment is $\\mu_M\\,(\\text{DI})=-0.022(11)(09)\\,\\mu_N$ and to the nucleon mean\nsquare charge radius is $\\langle r^2\\rangle_E\\,\\text{(DI)}=-0.019(05)(05)$\nfm$^2$ which is about $1/3$ of the difference between the $\\langle\nr_p^2\\rangle_E$ of electron-proton scattering and that of muonic atom and so\ncannot be ignored in obtaining the proton charge radius in the lattice QCD\ncalculation. The most important outcome of this lattice QCD calculation is that\nwhile the combined light-sea and strange quarks contribution to the nucleon\nmagnetic moment is small at about $1\\%$, a negative $2.5(9)\\%$ contribution to\nthe proton mean square charge radius and a relatively larger positive\n$16.3(6.1)\\%$ contribution to the neutron mean square charge radius come from\nthe sea quarks in the nucleon. For the first time, by performing global fits,\nwe also give predictions of the light and strange disconnected-sea quarks\ncontributions to the nucleon electric and magnetic form factors at the physical\npoint and in the continuum and infinite volume limits in the momentum transfer\nrange of $0\\leq Q^2\\leq 0.5$ GeV$^2$.",
        "positive": "Nucleon axial charge in domain-wall QCD with physical mass: Nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated\non a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass\njointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with\nlattice cut off of 1.730(4) GeV, are reported with about a percent statistical\nerrors, along with isovector ``scalar,'' $g_S$, and ``tensor charges,'' $g_T$,\nwith larger statistical errors. Nucleon mass is estimated as 947(6) MeV. A few\nstandard-deviation systematics is seen in the vector charge, likely from\n$O(a^2)$ discretization error through small excited-state contamination. The\naxialvector charge is found with a few to several standard-deviation systematic\ndeficit, depending on calculation methods, in comparison with the experiment.\nNucleon signal is likely lost as early as 10 lattice units or about 1.1 fm in\ntime from the source."
    },
    {
        "anchor": "Renormalization on the fuzzy sphere: We study renormalization on the fuzzy sphere, which is a typical example of\nnon-commutative spaces. We numerically simulate a scalar field theory on the\nfuzzy sphere, which is described by a Hermitian matrix model. We define\ncorrelation functions by using the Berezin symbol and show that they are made\nindependent of the matrix size, which plays a role of a UV cutoff, by tuning\none parameter of the theory. We also find that the theories on the phase\nboundary are universal. They behave as a conformal field theory at short\ndistances, while they universally differ from it at long distances due to the\nUV/IR mixing.",
        "positive": "Machine Learning Trivializing Maps: A First Step Towards Understanding\n  How Flow-Based Samplers Scale Up: A trivializing map is a field transformation whose Jacobian determinant\nexactly cancels the interaction terms in the action, providing a representation\nof the theory in terms of a deterministic transformation of a distribution from\nwhich sampling is trivial. Recently, a proof-of-principle study by Albergo,\nKanwar and Shanahan [arXiv:1904.12072] demonstrated that approximations of\ntrivializing maps can be `machine-learned' by a class of invertible,\ndifferentiable neural models called \\textit{normalizing flows}. By ensuring\nthat the Jacobian determinant can be computed efficiently, asymptotically exact\nsampling from the theory of interest can be performed by drawing samples from a\nsimple distribution and passing them through the network. From a theoretical\nperspective, this approach has the potential to become more efficient than\ntraditional Markov Chain Monte Carlo sampling techniques, where\nautocorrelations severely diminish the sampling efficiency as one approaches\nthe continuum limit. A major caveat is that it is not yet understood how the\nsize of models and the cost of training them is expected to scale. As a first\nstep, we have conducted an exploratory scaling study using two-dimensional\n$\\phi^4$ with up to $20^2$ lattice sites. Although the scope of our study is\nlimited to a particular model architecture and training algorithm, initial\nresults paint an interesting picture in which training costs grow very quickly\nindeed. We describe a candidate explanation for the poor scaling, and outline\nour intentions to clarify the situation in future work."
    },
    {
        "anchor": "Exploring the phase structure of 12-flavor $SU(3)$: We are studying the $SU(3)$ gauge theory with 12 staggered fermions,\nsearching for the endpoint of the line of first-order phase transitions in the\nmass--beta plane. This endpoint plays an important role in our understanding of\nthe phase diagram of this model. Having found this endpoint with high\nstatistics on a small lattice using unimproved staggered fermions, we are\nworking to find it on larger lattices and with improved actions. For an action\nimproved with nHYP-smeared staggered fermions, we discuss the effect of slowly\nturning off the improvement on the broken shift symmetry phase.",
        "positive": "Lattice Determination of the Anomalous Magnetic Moment of the Muon: We compute the leading hadronic contribution to the anomalous magnetic moment\nof the muon a_mu^HLO using two dynamical flavours of non-perturbatively O(a)\nimproved Wilson fermions. By applying partially twisted boundary conditions we\nare able to improve the momentum resolution of the vacuum polarisation, an\nimportant ingredient for the determination of the leading hadronic\ncontribution. We check systematic uncertainties by studying several ensembles,\nwhich allows us to discuss finite size effects and lattice artefacts. The\nchiral behavior of a_mu^HLO turns out to be non-trivial, especially for small\npion masses."
    },
    {
        "anchor": "A new strategy for evaluating the LO HVP contribution to $(g-2)_\u03bc$ on\n  the lattice: A highly physical model of the subtracted $I=1$ vector polarization, obtained\nusing a dispersive representation with precise hadronic $\\tau$ decay data as\ninput, is used to investigate systematic issues in the lattice evaluation of\nthe leading order hadronic vacuum polarization contribution to the anomalous\nmagnetic moment of the muon. The model is also employed to study possible\nresolutions of these problems. A hybrid approach to analyzing lattice data,\ninvolving low-order Pad\\'e, low-degree conformal-variable polynomial, or\nsupplemented NNLO ChPT fits for $Q^2$ below $\\sim 0.1-0.2$ GeV$^2$ and direct\nnumerical integration of lattice data above this point, is shown to bring the\nsystematic issues identified under control at the sub-$1\\%$ level.",
        "positive": "Towards a new determination of the QCD Lambda parameter from running\n  couplings in the three-flavour theory: We review our new strategy and current status towards a high precision\ncomputation of the Lambda parameter from three-flavour simulations in QCD. To\nreach this goal we combine specific advantages of the Schr\\\"odinger functional\nand gradient flow couplings."
    },
    {
        "anchor": "Towards the glueball spectrum from unquenched lattice QCD: We use a variational technique to study heavy glueballs on gauge\nconfigurations generated with 2+1 flavours of ASQTAD improved staggered\nfermions. The variational technique includes glueball scattering states. The\nmeasurements were made using 2150 configurations at 0.092 fm with a pion mass\nof 360 MeV. We report masses for 10 glueball states. We discuss the prospects\nfor unquenched lattice QCD calculations of the oddballs.",
        "positive": "Chiral Symmetry Outside Perturbation Theory: Within the overlap framework, I derive the main formulae one finds today in\npapers touting a ``new approach'' to the regularization of chiral gauge\ntheories. My main objective is to clear up an unhealthy confusion about how\nmany successful approaches to regulate chiral fermions on the lattice there\nreally are: At the moment, there is only one, the overlap, and finding a\ngenuinely different approach is an important and completely open problem."
    },
    {
        "anchor": "Perfect Lattice Actions for Staggered Fermions: We construct a perfect lattice action for staggered fermions by blocking from\nthe continuum. The locality, spectrum and pressure of such perfect staggered\nfermions are discussed. We also derive a consistent fixed point action for free\ngauge fields and discuss its locality as well as the resulting static\nquark-antiquark potential. This provides a basis for the construction of\n(classically) perfect lattice actions for QCD using staggered fermions.",
        "positive": "Classical solutions with nontrivial holonomy in SU(2) LGT at T \\ne 0: We generate SU(2) lattice gauge fields at finite temperature and cool them in\norder to characterize the two phases by the occurrence of specific classical\nsolutions.We apply two kinds of spatial boundary conditions: fixed holonomy and\nstandard periodic b.c. For T < T_c our findings concerning classical\nconfigurations semi-quantitatively agree for both types of boundary conditions.\nWe find in the confinement phase a mixture of undissociated calorons with lumps\nof positive or negative half-integer topological charges."
    },
    {
        "anchor": "Challenges Implementing non-Abelian SU(2) Quantum Chromodynamics Gauge\n  Links On a Universal Quantum Computer: The traditional approach for studying the physics of the strong interactions\nemploys a basic computational construct originally proposed by Wilson in the\n1970s. Over the years additional enhancements have been added to this\nformulation to improve computational performance and accuracy. This formulation\nhas been successfully implemented on high performance computing systems and has\nyielded accurate calculations for many static properties of the strong\ninteractions (such as the hadron mass spectrum). With the recent advances in\nquantum computing, the question that is now being asked is whether an\nequivalent type of gauge invariant formulation of a field theory can be\nconstructed on a quantum computer to calculate dynamical processes that cannot\nbe simulated on a traditional supercomputer. Using the Quantum Link Model (QLM)\nplus the concept of rishons, this paper will specifically focus on the\nchallenges implementing a basic gauge link lattice construct using SU(2)\nnon-Abelian links for illustration. The paper will also discuss the physics\nthat may potentially be simulated on a quantum computer with this construct and\nspeculate on the prospects for having quantum computers become a part of the\nset of hardware platforms for lattice gauge theory simulations in the future.",
        "positive": "Determining the chiral condensate from the distribution of the winding\n  number beyond topological susceptibility: The first two non-trivial moments of the distribution of the topological\ncharge (or gluonic winding number), i.e., the topological susceptibility and\nthe fourth cumulant, can be computed in lattice QCD simulations and exploited\nto constrain the pattern of chiral symmetry breaking. We compute these two\ntopological observables at next-to-leading order in three-flavour Chiral\nPerturbation Theory, and we discuss the role played by the eta propagation in\nthese expressions. For hierarchies of light-quark masses close to the physical\nsituation, we show that the fourth cumulant has a much better sensitivity than\nthe topological susceptibility to the three-flavour quark condensate, and thus\nconstitutes a relevant tool to determine the pattern of chiral symmetry\nbreaking in the limit of three massless flavours. We provide the complete\nformulae for the two topological observables in the isospin limit, and predict\ntheir values in the particular setting of the recent analysis of the RBC/UKQCD\ncollaboration. We show that a combination of the topological susceptibility and\nthe fourth cumulant is able to pin down the three-flavour condensate in a\nparticularly clean way in the case of three degenerate quarks."
    },
    {
        "anchor": "The Spectrum of the Kazakov Migdal-Model: Gross has found an exact expression for the density of eigenvalues in the\nsimplest version of the Kazakov-Migdal model of induced QCD. In this paper we\ncompute the spectrum of small fluctuations around Gross's semi-circular\nsolution. By solving Migdal's wave equation we find a string-like spectrum\nwhich, in four dimensions, corresponds to the infinite tower of mesons in\nstrong coupling lattice QCD with adjoint matter. In one dimension our formula\nreproduces correctly the well known spectrum of the hermitean matrix model with\na harmonic oscillator potential. We comment on the relevance of our results to\nthe possibility of the model describing extended objects in more than one\ndimension.",
        "positive": "Chiral Transition of SU(4) Gauge Theory with Fermions in Multiple\n  Representations: We report preliminary results on the finite temperature behavior of SU(4)\ngauge theory with dynamical quarks in both the fundamental and two-index\nantisymmetric representations. This system is a candidate to present scale\nseparation behavior, where fermions in different representations condense at\ndifferent temperature or coupling scales. Our simulations, however, reveal a\nsingle finite-temperature phase transition at which both representations\ndeconfine and exhibit chiral restoration. It appears to be strongly first\norder. We compare our results to previous single-representation simulations. We\nalso describe a Pisarski-Wilczek stability analysis, which suggests that the\ntransition should be first order."
    },
    {
        "anchor": "The locality of the square-root method for improved staggered quarks: We study the effects of improvement on the locality of square-rooted\nstaggered Dirac operators in lattice QCD simulations. We find the localisation\nlengths of the improved operators (FAT7TAD and ASQTAD) to be very similar to\nthat of the one-link operator studied by Bunk et al., being at least the\nCompton wavelength of the lightest particle in the theory, even in the\ncontinuum limit. We conclude that improvement has no effect. We discuss the\nimplications of this result for the locality of the nth-rooted fermion\ndeterminant used to reduce the number of sea quark flavours, and for possible\nstaggered valence quark formulations.",
        "positive": "$K \\rightarrow \u03c0\u03c0$ $\u0394I=3/2$ decay amplitude in the continuum\n  limit: We present new results for the amplitude $A_2$ for a kaon to decay into two\npions with isospin $I=2$: Re$A_2 =\n1.50(4)_\\mathrm{stat}(14)_\\mathrm{syst}\\times 10^{-8}$ GeV; Im$A_2 =\n-6.99(20)_\\mathrm{stat}(84)_\\mathrm{syst}\\times 10^{-13}$ GeV. These results\nwere obtained from two ensembles generated at physical quark masses (in the\nisospin limit) with inverse lattice spacings $a^{-1}=1.728(4)$ GeV and\n$2.358(7)$ GeV. We are therefore able to perform a continuum extrapolation and\nhence largely to remove the dominant systematic uncertainty from our earlier\nresults, that due to lattice artefacts. The only previous lattice computation\nof $K\\to\\pi\\pi$ decays at physical kinematics was performed using an ensemble\nat a single, rather coarse, value of the lattice spacing ($a^{-1}\\simeq\n1.37(1)$ GeV). We confirm the observation that there is a significant\ncancellation between the two dominant contributions to Re$A_2$ which we suggest\nis an important ingredient in understanding the $\\Delta I=1/2$ rule,\nRe$A_0$/Re$A_2\\simeq 22.5$, where the subscript denotes the total isospin of\nthe two-pion final state. Our result for $A_2$ implies that the electroweak\npenguin contribution to $\\epsilon^\\prime/\\epsilon$ is\nRe($\\epsilon^\\prime/\\epsilon)_\\textrm{EWP}=-(6.6\\pm 1.0)\\times 10^{-4}$."
    },
    {
        "anchor": "X(3872) and Y(4140) using diquark-antidiquark operators with lattice QCD: We perform a lattice study of charmonium-like mesons with $J^{PC}=1^{++}$ and\nthree quark contents $\\bar cc \\bar du$, $\\bar cc(\\bar uu+\\bar dd)$ and $\\bar cc\n\\bar ss$, where the later two can mix with $\\bar cc$. This simulation with\n$N_f=2$ and $m_\\pi=266$ MeV aims at the possible signatures of four-quark\nexotic states. We utilize a large basis of $\\bar cc$, two-meson and\ndiquark-antidiquark interpolating fields, with diquarks in both anti-triplet\nand sextet color representations. A lattice candidate for X(3872) with I=0 is\nobserved very close to the experimental state only if both $\\bar cc$ and $D\\bar\nD^*$ interpolators are included; the candidate is not found if\ndiquark-antidiquark and $D\\bar D^*$ are used in the absence of $\\bar cc$. No\ncandidate for neutral or charged X(3872), or any other exotic candidates are\nfound in the I=1 channel. We also do not find signatures of exotic $\\bar cc\\bar\nss$ candidates below 4.3 GeV, such as Y(4140). Possible physics and methodology\nrelated reasons for that are discussed. Along the way, we present the\ndiquark-antidiquark operators as linear combinations of the two-meson operators\nvia the Fierz transformations.",
        "positive": "Precision $B_c$ and $B_s$ mass calculations: We give improved results for B meson masses using NRQCD $b$ quarks and HISQ\nlight valence quarks for a range of lattice spacings and sea quark masses\nenabling controlled extrapolation to the physical point."
    },
    {
        "anchor": "Form factors of $B\\to\u03c0\\ell\u03bd$ and a determination of $|V_{ub}|$ with\n  M\u00f6bius domain-wall-fermions: Using a fully relativistic lattice fermion action, we compute the form\nfactors of the semileptonic decay $B\\to\\pi\\ell\\nu$, which is required for the\ndetermination of the Cabibbo-Kobayashi-Maskawa matrix element $|V_{ub}|$. We\nemploy the M\\\"{o}bius domain-wall fermion formalism for the generation of\nlattice ensembles with 2+1 sea quark flavours as well as for the valence heavy\nand light quarks. We compute the form factors at various values of the lattice\nspacing and multiple light and heavy quark masses, and extrapolate the results\nto the physical point. We combine our lattice results with the available\nexperimental data to obtain $|V_{ub}| = (3.93\\pm 0.41)\\times 10^{-3}$.",
        "positive": "(2+1)-flavor QCD Thermodynamics from the Gradient Flow: Recently, we proposed a novel method to define and calculate the\nenergy-momentum tensor (EMT) in lattice gauge theory on the basis of the\nYang-Mills gradient flow [1]. In this proceedings, we summarize the basic idea\nand technical steps to obtain the bulk thermodynamic quantities in lattice\ngauge theory using this method for the quenched and $(2+1)$-flavor QCD. The\nrevised results of integration measure (trace anomaly) and entropy density of\nthe quenched QCD with corrected coefficients are shown. Furthermore, we also\nshow the flow time dependence of the parts of EMT including the dynamical\nfermions. This work is based on a joint-collaboration between FlowQCD and WHOT\nQCD."
    },
    {
        "anchor": "P-wave heavy-light mesons using NRQCD and D234: The masses of S- and P-wave heavy-light mesons are computed in quenched QCD\nusing a classically and tadpole-improved action on anisotropic lattices. Of\nparticular interest are the splittings among P-wave states, which have not yet\nbeen resolved experimentally; even the ordering of these states continues to be\ndiscussed in the literature. The present work leads to upper bounds for these\nsplittings, and is suggestive, but not conclusive, about the ordering.",
        "positive": "Meson deformation by magnetic fields in lattice QCD: We study light meson properties in a magnetic field, focusing on a charged\npion and a charged and polarized rho meson, in quenched lattice QCD. The\ngauge-invariant density-density correlators are calculated to investigate the\ndeformation caused by the magnetic field. We find that these mesons acquire\nelongated shapes along the magnetic field. The magnitude of the deformation is\nabout 10-20 % when the strength of the magnetic field is of the order of the\nsquared unphysical pion mass."
    },
    {
        "anchor": "Tests of the lattice index theorem: We investigate the lattice index theorem and the localization of the\nzero-modes for thick classical center vortices. For non-orientable spherical\nvortices, the index of the overlap Dirac operator differs from the topological\ncharge although the traces of the plaquettes deviate only by a maximum of 1.5%\nfrom trivial plaquettes. This may be related to the fact that even in Landau\ngauge some links of these configuration are close to the non-trivial center\nelements.",
        "positive": "Change of theta dependence in 4D SU(N) gauge theories across the\n  deconfinement transition: We investigate the dependence of four-dimensional SU(N) gauge theories on the\ntopological theta term at finite temperature and, in particular, across the\ndeconfinement transition. For this purpose, we exploit the lattice formulation\nof the theory and present numerical results for the expansion of the free\nenergy up to O(theta^6), for N=3 and N=6.\n  Our numerical analysis shows that the theta dependence of 4D SU(N) gauge\ntheory experiences a drastic change across the deconfinement transition: the\nlow-temperature phase is characterized by a large-N scaling with theta/N as\nrelevant variable, while in the high-temperature phase the scaling variable is\njust theta and the free energy is essentially determined by the instanton-gas\napproximation. The crossover between the two different behaviours gets sharper\nwith increasing N, suggesting that the instanton-gas regime sets in just above\nTc at large N."
    },
    {
        "anchor": "Nonequilibrium Dynamics and Aging in the Three--Dimensional Ising Spin\n  Glass Model: The low temperature dynamics of the three dimensional Ising spin glass in\nzero field with a discrete bond distribution is investigated via MC\nsimulations. The thermoremanent magnetization is found to decay algebraically\nand the temperature dependent exponents agree very well with the experimentally\ndetermined values. The nonequilibrium autocorrelation function $C(t,t_w)$ shows\na crossover at the waiting (or {\\em aging}) time $t_w$ from algebraic {\\em\nquasi-equilibrium} decay for times $t$$\\ll$$t_w$ to another, faster algebraic\ndecay for $t$$\\gg$$t_w$ with an exponent similar to one for the remanent\nmagnetization.",
        "positive": "Equivariant Gauge Fixing of SU(2) Lattice Gauge Theory: I construct a Lattice Gauge Theory (LGT) with discrete Z_2 structure group\nand an equivariant BRST symmetry that is physically equivalent to the standard\nSU(2)-LGT. The measure of this Z_2-LGT is invariant under all the discrete\nsymmetries of the lattice and its partition function does not vanish. The\nTopological Lattice Theories (TLT) that localize on the moduli spaces are\nexplicitly constructed and their BRST symmetry is exhibited. The ghosts of the\nZ_2-invariant local LGT are integrated in favor of a nonlocal bosonic measure.\nIn addition to the SU(2) link variables and the coupling g^2, this effective\nbosonic measure also depends on an auxiliary gauge invariant site variable of\ncanonical dimension two and on a gauge parameter \\alpha. The relation between\nthe expectation value of the auxiliary field, the gauge parameter \\alpha and\nthe lattice spacing $a$ is obtained to lowest order in the loop expansion. In\nfour dimensions and the critical limit this expectation value is a physical\nscale proportional to \\Lambda_L in the gauge \\alpha=g^2 (11-n_f)/24+ O(g^4).\nImplications for the loop expansion of observables in such a critical gauge are\ndiscussed."
    },
    {
        "anchor": "QCD thermodynamics on the lattice: A remarkable progress has been made in the understanding of the hot and dense\nQCD matter using lattice gauge theory. The issues which are very well\nunderstood as well those which require both conceptual as well as algorithmic\nadvances are highlighted. The recent lattice results on QCD thermodynamics\nwhich are important in the context of the heavy ion experiments are reviewed.\nInstances of greater synergy between the lattice theory and the experiments in\nthe recent years are discussed where lattice results could be directly used as\nbenchmarks for experiments and results from the experiments would be a crucial\ninput for lattice computations.",
        "positive": "Glueball Wave Functions in U(1) Lattice Gauge Theory: Standard Monte Carlo simulations have been performed for 3-dimensional U(1)\nlattice gauge model on improved lattices to measure the wavefunction and size\nof the scalar and the tensor glueballs. Our results show the radii of ~ 0.60\nand ~ 1.12 in the units of string tension, or ~0.28 and ~0.52 fm, for the\nscalar and tensor glueballs, respectively. At finite temperature we see clear\nevidence of the deconfined phase, and the transition appears to be similar to\nthat of the two-dimensional XY model as expected from universality arguments.\nPreliminary results show no significant changes in the glueball wave functions\nand the masses in the deconfined phase."
    },
    {
        "anchor": "New Ideas in Finite Density QCD: We introduce a new approach to analyze the phase diagram of QCD at finite\nchemical potential and temperature, based on the definition of a generalized\nQCD action. Several details of the method will be discussed, with particular\nemphasis on the advantages respect to the imaginary chemical potential\napproach.",
        "positive": "Instanton Effects in Hadron Spectroscopy Revisited: We use an optimised clover action to study spectroscopy on an instanton\nensemble reconstructed from smoothed Monte Carlo configurations. Due to the\nbetter chirality of the clover action, the artificial configurations show a\nmarked difference from the free field behaviour obtained with the Wilson\naction. They however still fail to reproduce the physics observed on the\nsmoothed configurations. The presence of freely propagating quark modes is\nfound to be responsible for this."
    },
    {
        "anchor": "Topological susceptibility and string tension in CP(N-1) models: We investigate the features of ${\\rm CP}^{N-1}$ models concerning confinement\nand topology. In order to study the approach to the large-$N$ asymptotic\nregime, we determine the topological susceptibility and the string tension for\na wide range of values of $N$, in particular $N=4,10,21,41$. Quantitative\nagreement with the large-$N$ predictions is found for the ${\\rm CP}^{20}$ and\nthe ${\\rm CP}^{40}$ models. Problems related to the measure of the topological\nsusceptibility and the string tension on the lattice are discussed.",
        "positive": "Critical behavior and net-charge fluctuations from lattice QCD: We present recent results on the critical and pseudo-critical temperatures in\n(2+1)-flavor QCD with a physical strange quark mass and two degenerate light\nquark masses extrapolated to the chiral limit and tuned to the physical value,\nrespectively. We furthermore discuss implication of the observed low chiral\nphase transition temperature, Tc0=132_{-6}^{+3} MeV, for the structure of\ncumulants of conserved charge fluctuations at vanishing baryon chemical\npotential and consequences for the possible location of the QCD critical\nendpoint in the QCD phase diagram at non-zero baryon chemical potential."
    },
    {
        "anchor": "Deep-inelastic scattering and the operator product expansion in lattice\n  QCD: We discuss the determination of deep-inelastic hadron structure in lattice\nQCD. By using a fictitious heavy quark, direct calculations of the Compton\nscattering tensor can be performed in Euclidean space that allow the extraction\nof the moments of structure functions. This overcomes issues of operator mixing\nand renormalisation that have so far prohibited lattice computations of higher\nmoments. This approach is especially suitable for the study of the twist-two\ncontributions to isovector quark distributions, which is practical with current\ncomputing resources. While we focus on the isovector unpolarised distribution,\nour method is equally applicable to other quark distributions and to\ngeneralised parton distributions. By looking at matrix elements such as\n$<\\pi^\\pm| T [V^\\mu(x) A^{\\nu}(0)]|0>$ (where $V^\\mu$ and $A^\\nu$ are vector\nand axial-vector heavy-light currents) within the same formalism, moments of\nmeson distribution amplitudes can also be extracted.",
        "positive": "Fixed scale approach to the equation of state on the lattice: We propose a fixed scale approach to calculate the equation of state (EOS) in\nlattice QCD. In this approach, the temperature T is varied by Nt at fixed\nlattice spacings. This enables us to reduce T=0 simulations which are required\nto provide basic data in finite temperature studies but are quite expensive in\nthe conventional fixed-Nt approach. Since the conventional integral method to\nobtain the pressure is inapplicable at fixed scale, we introduce a new method,\n\"T-integration method\", to calculate pressure non-perturbatively. We test the\nfixed scale approach armed with the T-integral method in quenched QCD on\nisotropic and anisotropic lattices. Our method is found to be powerful to\nobtain reliable results for the equation of state, especially at intermediate\nand low temperatures. Reduction of the computational cost of T=0 simulations is\nindispensable to study EOS in QCD with dynamical quarks. The status of our\nstudy in Nf=2+1 QCD with improved Wilson quarks is also reported."
    },
    {
        "anchor": "A general study on the volume dependence of spectral weights in lattice\n  field theory: It has been suggested that the volume dependence of the spectral weight could\nbe utilized to distinguish single and multi-particle states in Monte Carlo\nsimulations. In a recent study using a solvable model, the Lee model, we found\nthat this criteria is applicable only for stable particles and narrow\nresonances, not for the broad resonances. In this paper, the same question is\naddressed within the finite size formalism outlined by L\\\"uscher. Using a\nquantum mechanical scattering model, the conclusion that was found in previous\nLee model study is recovered. Then, following similar arguments as in\nL\\\"uscher's, it is argued that the result is valid for a general massive\nquantum field theory under the same conditions as the L\\\"uscher's formulae.\nUsing the spectral weight function, a possibility of extracting resonance\nparameters is also pointed out.",
        "positive": "Recent Results on the Nucleon Structure Functions from Lattice QCD: We report on recent results of a high statistics lattice calculation of the\nunpolarized and polarized structure functions of the nucleon."
    },
    {
        "anchor": "Light hadron spectrum with two flavors of $O(a)$ improved dynamical\n  quarks : final results from JLQCD: We present the final results of the JLQCD calculation of the light hadron\nspectrum and quark masses with two flavors of dynamical quarks using the\nplaquette gauge action and fully $O(a)$-improved Wilson quark action at\n$\\beta=5.2$. We observe that sea quark effects lead to a closer agreement of\nthe strange meson and baryon masses with experiment and a reduction of quark\nmasses by about 25.",
        "positive": "FLIC Overlap Fermions: The action of the overlap-Dirac operator on a vector is typically implemented\nindirectly through a multi-shift conjugate gradient solver. The compute-time\nrequired depends upon the condition number, $\\kappa$, of the matrix that is\nused as the overlap kernel. While the Wilson action is typically used as the\noverlap kernel, the FLIC (Fat Link Irrelevant Clover) action has an improved\ncondition number and provides up to a factor of two speedup in evaluating the\noverlap action. We summarize recent progress on the use of FLIC overlap\nfermions."
    },
    {
        "anchor": "Topological susceptibility of $N_f=2+1$ QCD from staggered fermions\n  spectral projectors at high temperatures: We compute the topological susceptibility of $N_f=2+1$ QCD with physical\nquark masses in the high-temperature phase, using numerical simulations of the\ntheory discretized on a space-time lattice. More precisely we estimate the\ntopological susceptibility for five temperatures in the range from $\\sim200$\nMeV up to $\\sim600$ MeV, adopting the spectral projectors definition of the\ntopological charge based on the staggered Dirac operator. This strategy turns\nout to be effective in reducing the large lattice artifacts which affect the\nstandard gluonic definition, making it possible to perform a reliable continuum\nextrapolation. Our results for the susceptibility in the explored temperature\nrange are found to be partially in tension with previous determinations in the\nliterature.",
        "positive": "General purpose lattice QCD code set Bridge++ 2.0 for high performance\n  computing: Bridge++ is a general-purpose code set for a numerical simulation of lattice\nQCD aiming at a readable, extensible, and portable code while keeping\npractically high performance. The previous version of Bridge++ is implemented\nin double precision with a fixed data layout. To exploit the high arithmetic\ncapability of new processor architecture, we extend the Bridge++ code so that\noptimized code is available as a new branch, i.e., an alternative to the\noriginal code. This paper explains our strategy of implementation and displays\napplication examples to the following architectures and systems: Intel AVX-512\non Xeon Phi Knights Landing, Arm A64FX-SVE on Fujitsu A64FX (Fugaku), NEC\nSX-Aurora TSUBASA, and GPU cluster with NVIDIA V100."
    },
    {
        "anchor": "All-mode Renormalization for Tensor Network with Stochastic Noise: In usual (non-stochastic) tensor network calculations, the truncated singular\nvalue decomposition (SVD) is often used for approximating a tensor, and it\ncauses systematic errors. By introducing stochastic noise in the approximation,\nhowever, one can avoid such systematic errors at the expense of statistical\nerrors which can be straightforwardly controlled. Therefore in principle, exact\nresults can be obtained even at finite bond dimension up to the statistical\nerrors. A previous study of the unbiased method implemented in tensor\nrenormalization group (TRG) algorithm, however, showed that the statistical\nerrors for physical quantity are not negligible, and furthermore the\ncomputational cost is linearly proportional to a system volume. In this paper,\nwe introduce a new way of stochastic noise such that the statistical error is\nsuppressed, and moreover, in order to reduce the computational cost we propose\ncommon noise method whose cost is proportional to the logarithm of volume. We\nfind that the method provides better accuracy for the free energy compared with\nthe truncated SVD when applying to TRG for Ising model on square lattice.\nAlthough the common noise method introduces systematic error originated from a\ncorrelation of noises, we show that the error can be described by a simple\nfunctional form in terms of the number of noises, thus the error can be\nstraightforwardly controlled in an actual analysis. We also apply the method to\nthe graph independent local truncation algorithm and show that the accuracy is\nfurther improved.",
        "positive": "Application of Noncommutative Differential Geometry on Lattice to\n  Anomaly: The chiral anomaly in lattice abelian gauge theory is investigated by\napplying the geometric and topological method in noncommutative differential\ngeometry(NCDG). A new kind of double complex and descent equation are proposed\non infinite hypercubic lattice in arbitrary even dimensional Euclidean space,\nin the framework of NCDG. Using the general solutions to proposed descent\nequation, we derive the chiral anomaly in Abelian lattice gauge theory. The\ntopological origin of anomaly is nothing but the Chern classes in NCDG."
    },
    {
        "anchor": "Finite Temperature QCD on Anisotropic Lattices: We present results for mesonic propagators in temporal and spatial direction\nand for topological properties at T below and above the deconfining transition\nin quenched QCD. We use anisotropic lattices and Wilson fermions.",
        "positive": "Running HMC Simulation with Python via QUDA: Lyncs-API is a Python API for Lattice QCD applications. It is designed as a\nPython toolkit that allows the user to use and run various lattice QCD\nlibraries while programming in Python. The goal is to provide the user an easy\nprogramming experience without scarifying performance across multiple\nplatforms, by preparing a common framework for various softwares for lattice\nQCD calculations. As such, it contains interfaces to, e.g., c-lime, DDalphaAMG,\ntmLQCD, and QUDA. In this proceeding, we focus on a Lyncs interface to QUDA,\nnamed Lyncs-QUDA, and present a small tutorial on how to use this Python\ninterface to perform a HMC simulation using QUDA."
    },
    {
        "anchor": "RI/MOM renormalization constants (N_f=4) and the strong coupling\n  constant (N_f=2+1+1) from twisted-mass QCD: We study RI/MOM renormalization constants of bilinear quark operators for\n$N_f=4$ and the strong coupling constant for $N_f=2+1+1$ using Wilson\ntwisted-mass fermions. We use the \"egalitarian\" method to remove H(4)\nhypercubic artifacts non-perturbatively, which enables us to study physical\nquantities in a wide range of momenta. We then apply OPE in studying the\nrunning behavior of $Z_q$ and $\\alpha_s$, from which we are able to extract the\nLandau gauge dimension-two gluon condensate $<A^2>$ which is of\nphenomenological interest.",
        "positive": "The density of states approach at finite chemical potential: a numerical\n  study of the Bose gas: Recently, a novel algorithm for computing the density of states in\nstatistical systems and quantum field theories has been proposed. The same\nmethod can be applied to theories at finite density affected by the notorious\nsign problem, reducing a high-dimensional oscillating integral to a more\ntractable one-dimensional one. As an example we applied the method to the\nrelativistic Bose gas."
    },
    {
        "anchor": "Nucleon axial charge in 2+1 flavor dynamical lattice QCD with domain\n  wall fermions: We present results for the nucleon axial charge g_A at a fixed lattice\nspacing of 1/a=1.73(3) GeV using 2+1 flavors of domain wall fermions on size\n16^3x32 and 24^3x64lattices (L=1.8 and 2.7 fm) with length 16 in the fifth\ndimension. The length of the Monte Carlo trajectory at the lightest m_\\pi is\n7360 units, including 900 for thermalization. We find finite volume effects are\nlarger than the pion mass dependence at m_\\pi= 330 MeV. We also find that g_A\nexhibits a scaling with the single variable m_\\pi L which can also be seen in\nprevious two-flavor domain wall and Wilson fermion calculati ons. Using this\nscaling to eliminate the finite-volume effect, we obtain g_A = 1.20(6)(4) at\nthe physical pion mass, m_\\pi = 135 MeV, where the first and second errors are\nstatistical and systematic. The observed finite-volume scaling also appears in\nsimilar quenched simulations, but disappear when V\\ge (2.4 fm)^3. We argue this\nis a dynamical quark effect.",
        "positive": "Lattice QCD at the physical point meets SU(2) chiral perturbation theory: We perform a detailed, fully-correlated study of the chiral behavior of the\npion mass and decay constant, based on 2+1 flavor lattice QCD simulations.\nThese calculations are implemented using tree-level, O(a)-improved Wilson\nfermions, at four values of the lattice spacing down to 0.054 fm and all the\nway down to below the physical value of the pion mass. They allow a sharp\ncomparison with the predictions of SU(2) chiral perturbation theory (\\chi PT)\nand a determination of some of its low energy constants. In particular, we\nsystematically explore the range of applicability of NLO SU(2) \\chi PT in two\ndifferent expansions: the first in quark mass (x-expansion), and the second in\npion mass (\\xi-expansion). We find that these expansions begin showing signs of\nfailure around M_\\pi=300 MeV for the typical percent-level precision of our\nN_f=2+1 lattice results. We further determine the LO low energy constants\n(LECs), F=88.0 \\pm 1.3\\pm 0.3 and B^\\msbar(2 GeV)=2.58 \\pm 0.07 \\pm 0.02 GeV,\nand the related quark condensate, \\Sigma^\\msbar(2 GeV)=(271\\pm 4\\pm 1 MeV)^3,\nas well as the NLO ones, l_3=2.5 \\pm 0.5 \\pm 0.4 and l_4=3.8 \\pm 0.4 \\pm 0.2,\nwith fully controlled uncertainties. We also explore the NNLO expansions and\nthe values of NNLO LECs. In addition, we show that the lattice results favor\nthe presence of chiral logarithms. We further demonstrate how the absence of\nlattice results with pion masses below 200 MeV can lead to misleading results\nand conclusions. Our calculations allow a fully controlled, ab initio\ndetermination of the pion decay constant with a total 1% error, which is in\nexcellent agreement with experiment."
    },
    {
        "anchor": "Magnetic Monopole Content of Hot Instantons: We study the Abelian projection of an instanton in $R^3 \\times S^1$ as a\nfunction of temperature (T) and non-trivial holonomic twist ($\\omega$) of the\nPolyakov loop at infinity. These parameters interpolate between the circular\nmonopole loop solution at T=0 and the static 't Hooft-Polyakov\nmonopole/anti-monopole pair at high temperature.",
        "positive": "Lattice Gravity and Random Surfaces: I review recent progress in simplicial quantum gravity in three and four\ndimensions, in particular new results on the phase structure of modified models\nof dynamical triangulations, the application of a strong-coupling expansion,\nand the benefits provided by including degenerate triangulations. In addition,\nI describe some recent numerical and analytical results on anisotropic\ncrystalline membranes."
    },
    {
        "anchor": "Fermion bag solutions to some sign problems in four-fermion field\n  theories: Lattice four-fermion models containing $N$ flavors of staggered fermions,\nthat are invariant under $Z_2$ and U(1) chiral symmetries, are known to suffer\nfrom sign problems when formulated using the auxiliary field approach. Although\nthese problems have been ignored in previous studies, they can be severe. Here\nwe show that the sign problems disappear when the models are formulated in the\nfermion bag approach, allowing us to solve them rigorously for the first time.",
        "positive": "Controlling the Sign Problem in Finite Density Quantum Field Theory: Quantum field theories at finite matter densities generically possess a\npartition function that is exponentially suppressed with the volume compared to\nthat of the phase quenched analogue. The smallness arises from an almost\nuniform distribution for the phase of the fermion determinant. Large\ncancellations upon integration is the origin of a poor signal to noise ratio.\nWe study three alternatives for this integration: the Gaussian approximation,\nthe \"telegraphic\" approximation, and a novel expansion in terms of\ntheory-dependent moments and universal coefficients. We have tested the methods\nfor QCD at finite densities of heavy quarks. We find that for two of the\napproximations the results are extremely close - if not identical - to the full\nanswer in the strong sign problem regime."
    },
    {
        "anchor": "Hadrons at high temperature: an update from the FASTSUM collaboration: We present the most recent results from the FASTSUM collaboration for hadron\nproperties at high temperature. This includes the temperature dependence of the\nlight and charmed meson and baryon spectrum, as well as properties of heavy\nquarkonia. The results are obtained using anisotropic lattices with a fixed\nscale approach. We also present the status of our next generation gauge\nensembles.",
        "positive": "Efficient use of the Generalized Eigenvalue Problem: We analyze the systematic errors made when using the generalized eigenvalue\nproblem to extract energies and matrix elements in lattice gauge theory.\nEffective theories such as HQET are also discussed. Numerical results are shown\nfor the extraction of ground-state and excited B-meson masses and the\nground-state decay constant in the static approximation."
    },
    {
        "anchor": "Sivers and Boer-Mulders observables from lattice QCD: We present a first calculation of transverse momentum dependent nucleon\nobservables in dynamical lattice QCD employing non-local operators with\nstaple-shaped, \"process-dependent\" Wilson lines. The use of staple-shaped\nWilson lines allows us to link lattice simulations to TMD effects determined\nfrom experiment, and in particular to access non-universal, naively\ntime-reversal odd TMD observables. We present and discuss results for the\ngeneralized Sivers and Boer-Mulders transverse momentum shifts for the SIDIS\nand DY cases. The effect of staple-shaped Wilson lines on T-even observables is\nstudied for the generalized tensor charge and a generalized transverse shift\nrelated to the worm gear function g_1T. We emphasize the dependence of these\nobservables on the staple extent and the Collins-Soper evolution parameter. Our\nnumerical calculations use an n_f = 2+1 mixed action scheme with domain wall\nvalence fermions on an Asqtad sea and pion masses 369 MeV as well as 518 MeV.",
        "positive": "Non-perturbative renormalization in domain-wall QCD by Schr\u00f6dinger\n  functional scheme: We formulate and numerically test the Schr\\\"odinger functional scheme for\ndomain-wall QCD. We then apply it to a non-perturbative calculation of the\nrenormalization factors for vector and axial-vector currents in quenched\ndomain-wall QCD with plaquette and renormalization group improved gauge actions\nat $a^{-1}\\simeq 2$ GeV."
    },
    {
        "anchor": "Computing general observables in lattice models with complex actions: The study of QFTs at finite density is hindered by the presence of the\nso-called sign problem. The action definition of such systems is, in fact,\ncomplex-valued making standard importance sampling Monte Carlo methods\nineffective. In this work, we shall review the generalized density of states\nmethod for complex action systems and the Linear Logarithmic Relaxation\nalgorithm (LLR). We will focus on the recent developments regarding the bias\ncontrol of the LLR method and the evaluation of general observables in the\nDoS+LLR framework. Recent results on the well-known relativistic Bose gas will\nbe presented, proving that in our approach the phase factor can be consistently\nevaluated over hundreds of orders of magnitude. A first exploratory study on\nthe Thirring model in the DoS formalism will be presented as well.",
        "positive": "Calorons, monopoles and stable, charged solitons: We discuss the similarity of the constituent monopoles of calorons and stable\ntopological solitons with long range Coulombic interaction, classical solutions\nof the model of topological particles. In the interpretation as electric\ncharges they can be compared to electrons and positrons with spin up and down,\nwith quantised charge and finite mass."
    },
    {
        "anchor": "Perturbative matching of continuum and lattice quasi-distributions: Matching of the quasi parton distribution functions between continuum and\nlattice is addressed using lattice perturbation theory specifically with\nWilson-type fermions. The matching is done for nonlocal quark bilinear\noperators with a straight Wilson line in a spatial direction. We also\ninvestigate operator mixing in the renormalization and possible O(a) operators\nfor the nonlocal operators based on a symmetry argument on lattice.",
        "positive": "The continuum limit of the static-light meson spectrum: We investigate the continuum limit of the low lying static-light meson\nspectrum using Wilson twisted mass lattice QCD with N_f = 2 dynamical quark\nflavours. We consider three values of the lattice spacing a ~ 0.051 fm, 0.064\nfm, 0.080 fm and various values of the pion mass in the range 280 MeV < m_PS <\n640 MeV. We present results in the continuum limit for light cloud angular\nmomentum j = 1/2, 3/2, 5/2 and for parity P = +, -. We extrapolate our results\nto physical quark masses, make predictions regarding the spectrum of B and B_s\nmesons and compare with available experimental results."
    },
    {
        "anchor": "Spectroscopy of chimera baryons in a $Sp(4)$ lattice gauge theory: Chimera baryons are an important element of strongly coupled theories that\nprovide a microscopic origin for UV complete composite Higgs models (CHMs),\nsince they play the role of top partners in top partial compositeness. In a\nparticular interesting realisation of CHMs based upon an underlying $Sp(4)$\ngauge theory, such exotic objects are composed of two fermion constituents\ntransforming on the fundamental, and one on the 2-index antisymmetric\nrepresentations. We perform lattice computations of the chimera baryon spectrum\nin the quenched approximation. We present preliminary results for the masses of\nvarious chimera baryons with different quantum numbers, including the one\ninterpreted as the top partner. We test the technology needed for future\ncalculations with dynamical fermions.",
        "positive": "Measuring the Hausdorff Dimension of Quantum Mechanical Paths: We measure the propagator length in imaginary time quantum mechanics by Monte\nCarlo simulation on a lattice and extract the Hausdorff dimension $d_{H}$. We\nfind that all local potentials fall into the same universality class giving\n$d_{H}=2$ like the free motion. A velocity dependent action ($S \\propto \\int dt\n\\mid \\vec{v} \\mid^{\\alpha}$) in the path integral (e.g. electrons moving in\nsolids, or Brueckner's theory of nuclear matter) yields $d_{H}=\\frac{\\alpha\n}{\\alpha - 1}$ if $\\alpha > 2$ and $d_{H}=2$ if $\\alpha \\leq 2$. We discuss the\nrelevance of fractal pathes in solid state physics and in $QFT$, in particular\nfor the Wilson loop in $QCD$."
    },
    {
        "anchor": "QCD with chiral 4-fermion interactions ($\u03c7$QCD): Lattice QCD with staggered quarks is augmented by the addition of a chiral\n4-fermion interaction. The Dirac operator is now non-singular at $m_q=0$,\ndecreasing the computing requirements for light quark simulations by at least\nan order of magnitude. We present preliminary results from simulations at\nfinite and zero temperatures for $m_q=0$, with and without gauge fields.",
        "positive": "Light meson spectrum with $N_f=2+1$ dynamical overlap fermions: We report on a numerical simulation with 2+1 dynamical flavors of overlap\nfermions. We calculate pseudo-scalar masses and decay constants on a\n$16^3\\times 48 \\times (0.11 {\\rm fm})^4$ lattice at five different up and down\nquark masses and two strange quark masses. The lightest pion mass corresponds\nto $\\approx 310$ MeV. We also study the validity of the chiral perturbation\ntheory using the results of the numerical simulation with two dynamical flavors\nand conclude that the one-loop formulae cannot be directly applied in the\nstrange quark mass region. We therefore extrapolate our 2+1-flavor results to\nthe chiral limit by fitting the data to the two-loop formulae of the chiral\nperturbation theory."
    },
    {
        "anchor": "Charm degrees of freedom in hot matter from lattice QCD: We study the nature of charm degrees of freedom in hot strong interaction\nmatter by performing lattice QCD calculations of the second and fourth-order\ncumulants of charm fluctuations, and their correlations with net baryon number,\nelectric charge and strangeness fluctuations. We show that below the chiral\ncrossover temperature thermodynamics of charm can be very well understood in\nterms of charmed hadrons. Above the chiral transition charm quarks show up as\nnew degrees of freedom contributing to the partial charm pressure. However, up\nto temperatures as high as 175 MeV charmed hadron-like excitations provide a\nsignificant contribution to the partial charm pressure.",
        "positive": "Effective Potential for Complex Langevin Equations: We construct an effective potential for the complex Langevin equation on a\nlattice. We show that the minimum of this effective potential gives the\nspace-time and Langevin time average of the complex Langevin field. The loop\nexpansion of the effective potential is matched with the derivative expansion\nof the associated Schwinger-Dyson equation to predict the stationary\ndistribution to which the complex Langevin equation converges."
    },
    {
        "anchor": "Large pion pole in Z_{S}^{MOM}/Z_{P}^{MOM} from Wilson action data: We show that, contrarily to recent claims, data from the Wilson (unimproved)\nfermionic action at three different beta values demonstrate the presence of a\nlarge Goldstone boson contribution in the quark pseudoscalar vertex,\nquantitatively close to our previous estimate based on the SW action with\nc_{SW}=1.769. We show that discretisation errors on Z_{S}^{MOM}/Z_{P}^{MOM}\nseem to be much smaller than the Goldstone pole contribution over a very large\nrange of momenta. The subtraction of this non perturbative contribution leads\nto numbers close to one-loop BPT.",
        "positive": "Correlation functions between monopoles and instantons: We analyze the relation between instantons and abelian projected monopoles in\nboth phases of pure QCD by calculating local correlation functions between\ntopological charge densities and monopole densities. On an $8^{3} \\times 4$\nlattice, it turns out that topological quantities are correlated approximately\ntwo lattice spacings. The monopole-instanton correlations are rather\ninsensitive under cooling of gauge fields."
    },
    {
        "anchor": "SU(3) flavour symmetry breaking and charmed states: By extending the SU(3) flavour symmetry breaking expansion from up, down and\nstrange sea quark masses to partially quenched valence quark masses we propose\na method to determine charmed quark hadron masses including possible QCD\nisospin breaking effects. Initial results for some open charmed pseudoscalar\nmeson states and singly and doubly charmed baryon states are encouraging and\ndemonstrate the potential of the procedure. Essential for the method is the\ndetermination of the scale using singlet quantities, and to this end we also\ngive here a preliminary estimation of the recently introduced Wilson flow\nscales.",
        "positive": "Gluon propagators in maximal abelian gauge of SU(2) lattice gauge theory: We study propagators of diagonal and off-diagonal gluons in the momentum\nspace in maximal abelian gauge of SU(2) lattice gauge theory. Remaining U(1)\ndegrees of freedom are fixed using Landau gauge. We find substantial difference\nbetween the propagator of the diagonal and the off-diagonal gluon in the\ninfrared region. The propagator of the off-diagonal gluon is suppressed in\ncomparison with that of the diagonal gluon at small momenta. In the ultraviolet\nregion both propagators behave as in nonabelian Landau gauge."
    },
    {
        "anchor": "The spectrum of massive excitations of 3d 3-state Potts model and\n  universality: We consider the mass spectrum of the 3$d$ 3-state Potts model in the broken\nphase (a) near the second order Ising critical point in the temperature -\nmagnetic field plane and (b) near the weakly first order transition point at\nzero magnetic field. In the case (a), we compare the mass spectrum with the\nprediction from universality of mass ratios in the 3$d$ Ising class; in the\ncase (b), we determine a mass ratio to be compared with the corresponding one\nin the spectrum of screening masses of the (3+1)$d$ SU(3) pure gauge theory at\nfinite temperature in the deconfined phase near the transition. The agreement\nin the comparison in the case (a) would represent a non-trivial test of\nvalidity of the conjecture of spectrum universality. A positive answer to the\ncomparison in the case (b) would suggest the possibility to extend this\nconjecture to weakly first order phase transitions.",
        "positive": "Non-perturbative renormalisation of four-fermion operators in N_f=2 QCD: We present results for the non-perturbative renormalisation of four-fermion\noperators with two flavours of dynamical quarks. We consider both fully\nrelativistic left current-left current operators, and a full basis for $\\Delta\nB=2$ operators with static heavy quarks. The renormalisation group running of\nthe operators to high energy scales is computed in the continuum limit for a\nfamily of Schroedinger Functional renormalisation schemes, via standard finite\nsize scaling techniques. The total renormalisation factors relating\nrenormalisation group invariant to bare operators are computed for a choice of\nlattice regularisations."
    },
    {
        "anchor": "Disconnected contributions to the magnetic polarisability of the neutral\n  pion: The magnetic polarisability of the neutral pion has been calculated using the\nbackground field method in lattice QCD. These early results do not consider the\neffect of the disconnected loop contractions arising from the breaking of\ncharge symmetry in a background magnetic field. Recent work in chiral\nperturbation theory has shown that these quark-self-annihilation contractions\nprovide the leading loop-order contributions to the magnetic polarisability. A\nfirst investigation of these contractions in a background magnetic field is\npresented.",
        "positive": "Onset Transition to Cold Nuclear Matter from Lattice QCD with Heavy\n  Quarks: Lattice QCD at finite density suffers from a severe sign problem, which has\nso far prohibited simulations of the cold and dense regime. Here we study the\nonset of nuclear matter employing a three-dimensional effective theory derived\nby combined strong coupling and hopping expansions, which is valid for heavy\nbut dynamical quarks and has a mild sign problem only. Its numerical\nevaluations agree between a standard Metropolis and complex Langevin algorithm,\nwhere the latter is free of the sign problem. Our continuum extrapolated data\nclearly show a first order phase transition building up at $\\mu_B \\approx m_B$\nas the temperature approaches zero. An excellent description of the data is\nachieved by an analytic solution in the strong coupling limit."
    },
    {
        "anchor": "On the convergence of complex Langevin dynamics: the three-dimensional\n  XY model at finite chemical potential: The three-dimensional XY model is studied at finite chemical potential using\ncomplex Langevin dynamics. The validity of the approach is probed at small\nchemical potential using imaginary chemical potential and continuity arguments,\nand at larger chemical potential by comparison with the world line method.\nWhile complex Langevin works for larger beta, we find that it fails for smaller\nbeta, in the region of the phase diagram corresponding to the disordered phase.\nDiagnostic tests are developed to identify symptoms correlated with incorrect\nconvergence. We argue that the erroneous behaviour at smaller beta is not due\nto the sign problem, but rather resembles dynamics observed in complex Langevin\nsimulations of simple models with complex noise.",
        "positive": "Flow-based sampling for multimodal distributions in lattice field theory: Recent results have demonstrated that samplers constructed with flow-based\ngenerative models are a promising new approach for configuration generation in\nlattice field theory. In this paper, we present a set of methods to construct\nflow models for targets with multiple separated modes (i.e. theories with\nmultiple vacua). We demonstrate the application of these methods to modeling\ntwo-dimensional real scalar field theory in its symmetry-broken phase. In this\ncontext we investigate the performance of different flow-based sampling\nalgorithms, including a composite sampling algorithm where flow-based proposals\nare occasionally augmented by applying updates using traditional algorithms\nlike HMC."
    },
    {
        "anchor": "The Energy of n Identical Bosons in a Finite Volume at O(L^{-7}): The volume dependence of the ground-state energy of n identical bosons with\nshort-range interactions in a periodic spatial volume with sides of length L is\ncalculated at order L^{-7} in the large volume expansion. This result will\nenable a refined determination of the pi^+ pi^+ pi^+ interaction from lattice\nQCD calculations.",
        "positive": "$N\u03a9$ dibaryon from lattice QCD near the physical point: The nucleon($N$)-Omega($\\Omega$) system in the S-wave and spin-2 channel\n($^5$S$_2$) is studied from the (2+1)-flavor lattice QCD with nearly physical\nquark masses ($m_\\pi \\simeq 146$~MeV and $m_K \\simeq 525$~MeV). The\ntime-dependent HAL QCD method is employed to convert the lattice QCD data of\nthe two-baryon correlation function to the baryon-baryon potential and\neventually to the scattering observables. The $N\\Omega$($^5$S$_2$) potential,\nobtained under the assumption that its couplings to the D-wave octet-baryon\npairs are small, is found to be attractive in all distances and to produce a\nquasi-bound state near unitarity: In this channel, the scattering length, the\neffective range and the binding energy from QCD alone read $a_0=\n5.30(0.44)(^{+0.16}_{-0.01})$~fm, $r_{\\rm eff} =\n1.26(0.01)(^{+0.02}_{-0.01})$~fm, $B = 1.54(0.30)(^{+0.04}_{-0.10})$~MeV,\nrespectively. Including the extra Coulomb attraction, the binding energy of\n$p\\Omega^-$($^5$S$_2$) becomes $B_{p\\Omega^-} =\n2.46(0.34)(^{+0.04}_{-0.11})$~MeV. Such a spin-2 $p\\Omega^-$ state could be\nsearched through two-particle correlations in $p$-$p$, $p$-nucleus and\nnucleus-nucleus collisions."
    },
    {
        "anchor": "Monopole Percolation and The Universality Class of the Chiral Transition\n  in Four Flavor Noncompact Lattice QED: We simulate four flavor noncompact lattice QED using the Hybrid Monte Carlo\nalgorithm on $10^4$ and $16^4$ lattices. Measurements of the monopole\nsusceptibility and the percolation order parameter indicate a transition at\n$\\beta = {1/e^2} = .205(5)$ with critical behavior in the universality class of\nfour dimensional percolation. We present accurate chiral condensate\nmeasurements and monitor finite size effects carefully. The chiral condensate\ndata supports the existence of a power-law transition at $\\beta = .205$ in the\nsame universality class as the chiral transition in the two flavor model. The\nresulting equation of state predicts the mass ratio $m_\\pi^2/m_\\sigma^2$ in\ngood agreement with spectrum calculations while the hypothesis of a\nlogarithmically improved mean field theory fails qualitatively.",
        "positive": "Scalar Glueball Mass Reduction at Finite Temperature in SU(3)\n  Anisotropic Lattice QCD: We report the first study of the glueball properties at finite temperatures\nbelow T_c using SU(3) anisotropic lattice QCD with beta=6.25, the renormalized\nanisotropy xi \\equiv a_s/a_t = 4 and 20^3 \\times N_t\n(N_t=35,36,37,38,40,43,45,50,72) at the quenched level. From the temporal\ncorrelation analysis with the smearing method, about 20 % mass reduction is\nobserved for the lowest scalar glueball as m_G(T)=1250 \\pm 50MeV for 0.8 T_c <\nT < T_c in comparison with m_G \\simeq 1500 \\sim 1700MeV at T \\simeq 0."
    },
    {
        "anchor": "Light hadron masses with an $O(a^2)$ improved NNN action: Meson and baryon masses in the light (u,d and s) sector are calculated using\ntadpole-improved gauge field and fermion actions. These are corrected to order\n$O(a^2)$ on the classical level using next-nearest-neighbour terms. The\nresults, obtained at lattice spacings of 0.4 and 0.27fm, are compared to Wilson\naction calculations.",
        "positive": "The interface free energy: Comparison of accurate Monte Carlo results\n  for the 3D Ising model with effective interface models: We provide accurate Monte Carlo results for the free energy of interfaces\nwith periodic boundary conditions in the 3D Ising model. We study a large range\nof inverse temperatures, allowing to control corrections to scaling. In\naddition to square interfaces, we study rectangular interfaces for a large\nrange of aspect ratios u=L_1/L_2. Our numerical results are compared with\npredictions of effective interface models. This comparison verifies clearly the\neffective Nambu-Goto model up to two-loop order. Our data also allow us to\nobtain the estimates T_c sigma^-1/2=1.235(2), m_0++ sigma^-1/2=3.037(16) and\nR_+=f_+^2 sigma_0 =0.387(2), which are more precise than previous ones."
    },
    {
        "anchor": "Numerical investigation of lattice Weinberg - Salam model: Lattice Weinberg - Salam model without fermions for the value of the Weinberg\nangle $\\theta_W \\sim 30^o$, and bare fine structure constant around $\\alpha\n\\sim 1/150$ is investigated numerically. We consider the value of the scalar\nself coupling corresponding to bare Higgs mass around 150 GeV. We investigate\nphenomena existing in the vicinity of the phase transition between the physical\nHiggs phase and the unphysical symmetric phase of the lattice model. This is\nthe region of the phase diagram, where the continuum physics is to be\napproached. We find the indications that at the energies above 1 TeV\nnonperturbative phenomena become important in the Weinberg - Salam model.",
        "positive": "Neutron electric polarizability from unquenched lattice QCD using the\n  background field approach: A calculational scheme for obtaining the electric polarizability of the\nneutron in lattice QCD with dynamical quarks is developed, using the background\nfield approach. The scheme differs substantially from methods previously used\nin the quenched approximation, the physical reason being that the QCD ensemble\nis no longer independent of the external electromagnetic field in the dynamical\nquark case. One is led to compute (certain integrals over) four-point\nfunctions. Particular emphasis is also placed on the physical role of constant\nexternal gauge fields on a finite lattice; the presence of these fields\ncomplicates the extraction of polarizabilities, since it gives rise to an\nadditional shift of the neutron mass unrelated to polarizability effects. The\nmethod is tested on a SU(3) flavor-symmetric ensemble furnished by the MILC\nCollaboration, corresponding to a pion mass of m_pi = 759 MeV. Disconnected\ndiagrams are evaluated using stochastic estimation. A small negative electric\npolarizability of alpha =(-2.0 +/- 0.9) 10^(-4) fm^3 is found for the neutron\nat this rather large pion mass; this result does not seem implausible in view\nof the qualitative behavior of alpha as a function of m_pi suggested by Chiral\nEffective Theory."
    },
    {
        "anchor": "Revisiting strong coupling QCD at finite temperature and baryon density: The strong coupling limit ($\\beta_{gauge}=0$) of lattice QCD with staggered\nfermions enjoys the same non-perturbative properties as continuum QCD, namely\nconfinement and chiral symmetry breaking. In contrast to the situation at weak\ncoupling, the sign problem which appears at finite density can be brought under\ncontrol for a determination of the full (mu,T) phase diagram by Monte Carlo\nsimulations. Further difficulties with efficiency and ergodicity of the\nsimulations, especially at the strongly first-order, low-T, finite-mu\ntransition, are addressed respectively with a worm algorithm and multicanonical\nsampling. Our simulations reveal sizeable corrections to the old results of\nKarsch and Muetter. Comparison with analytic mean-field determinations of the\nphase diagram shows discrepancies of O(10) in the location of the QCD critical\npoint.",
        "positive": "Renormalisation group evolution for the $\u0394S = 1$ effective\n  Hamiltonian with $N_f=2+1$: We discuss the renormalisation group (RG) evolution for the $\\Delta S = 1$\noperators in unquenched QCD with $N_f = 3$ ($m_u=m_d=m_s$) or, more generally,\n$N_f = 2+1$ ($m_u=m_d \\ne m_s$) flavors. In particular, we focus on the\nspecific problem of how to treat the singularities which show up only for\n$N_f=3$ or $N_f = 2+1$ in the original solution of Buras {\\it et al.} for the\nRG evolution matrix at next-to-leading order. On top of Buras {\\it et al.}'s\noriginal treatment, we use a new method of analytic continuation to obtain the\ncorrect solution in this case. It is free of singularities and can therefore be\nused in numerical analysis of data sets calculated in lattice QCD."
    },
    {
        "anchor": "Universality of the gauge-ball spectrum of the four-dimensional pure\n  U(1) gauge theory: We continue numerical studies of the spectrum of the pure U(1) lattice gauge\ntheory in the confinement phase, initiated in our previous work. Using the\nextended Wilson action $ S = -\\sum_P [\\beta \\cos(\\Theta_P) + \\gamma\n\\cos(2\\Theta_P)] $ we address the question of universality of the phase\ntransition line in the ($\\beta,\\gamma$) plane between the confinement and the\nCoulomb phases. Our present results at $\\gamma= -0.5$ for the gauge-ball\nspectrum are fully consistent with the previous results obtained at $\\gamma=\n-0.2$. Again, two different correlation length exponents, $\\nu_{ng} = 0.35(3)$\nand $\\nu_{g} = 0.49(7)$, are obtained in different channels. We also confirm\nthe stability of the values of these exponents with respect to the variation of\nthe distance from the critical point at which they are determined. These\nresults further demonstrate universal critical behaviour of the model at least\nup to correlation lengths of 4 lattice spacings when the phase transition is\napproached in some interval at $\\gamma\\leq -0.2$.",
        "positive": "New approach to canonical partition functions computation in $N_f=2$\n  lattice QCD at finite baryon density: We propose and test a new approach to computation of canonical partition\nfunctions in lattice QCD at finite density. We suggest a few steps procedure.\nWe first compute numerically the quark number density for imaginary chemical\npotential $i\\mu_{qI}$. Then we restore the grand canonical partition function\nfor imaginary chemical potential using fitting procedure for the quark number\ndensity. Finally we compute the canonical partition functions using high\nprecision numerical Fourier transformation. Additionally we compute the\ncanonical partition functions using known method of the hopping parameter\nexpansion and compare results obtained by two methods in the deconfining as\nwell as in the confining phases. The agreement between two methods indicates\nthe validity of the new method. Our numerical results are obtained in two\nflavor lattice QCD with clover improved Wilson fermions."
    },
    {
        "anchor": "Path integral contour deformations for noisy observables: Monte Carlo studies of many quantum systems face exponentially severe\nsignal-to-noise problems. We show that noise arising from complex phase\nfluctuations of observables can be reduced without introducing bias using path\nintegral contour deformation techniques. A numerical study of contour\ndeformations for correlation functions in Abelian gauge theory and complex\nscalar field theory demonstrates that variance can be reduced by orders of\nmagnitude without modifying Monte Carlo sampling.",
        "positive": "Muon $g-2$: Lattice calculations of the hadronic vacuum polarization: The experimental uncertainty on the anomalous magnetic moment of the muon has\nbeen significantly reduced with the recent results of the Fermilab $g-2$\nexperiment, and a further reduction is expected in the near future. The\nprecision of the Standard Model prediction needs to improve correspondingly to\nincrease the sensitivity of tests for physics beyond the Standard Model. The\nlargest uncertainty is due to contributions from the strong interaction, in\nparticular the hadronic vacuum polarization (HVP) contribution. Lattice QCD\ncalculations have the potential to provide precise ab initio predictions of the\nHVP contribution. We review the state of lattice QCD calculations, focusing on\nthe dominant sources of uncertainty that need to be controlled to provide\nresults with sub-percent precision."
    },
    {
        "anchor": "Chiral perturbation theory for twisted mass QCD at small quark mass: We study the lattice cutoff ($a$) and quark mass dependences of pion masses\nand decay constants in the $N_f = 2$ twisted mass QCD, using the Wilson chiral\nperturbation theory to the next leading order (NLO). In order to investigate\nthe region near zero quark mass, we introduce the power counting scheme where\n$O(a^2, am)$ terms are included in the tree level effective Lagrangian. At the\nNLO of this power counting scheme, we calculate the charged pion mass and decay\nconstant as a function of the lattice cutoff as well as the twisted quark mass\nat the maximal twist. In this paper, we adopt two different definitions for the\nmaximal twist. We confirm that the difference between the two appears as the\n$O(a^2)$ effects so that the automatic $O(a)$ improvement is realized for both\ndefinitions.",
        "positive": "Search for low-lying lattice QCD eigenstates in the Roper regime: The positive-parity nucleon spectrum is explored in $2 + 1$-flavour lattice\nQCD in a search for new low-lying energy eigenstates near the energy regime of\nthe Roper resonance. In addition to conventional three-quark operators, we\nconsider novel, local five-quark meson-baryon type interpolating fields that\nhold the promise to reveal new eigenstates that may have been missed in\nprevious analyses. Drawing on phenomenological insight, five-quark operators\nbased on $\\sigma{N}$, $\\pi{N}$ and $a_0{N}$ channels are constructed. Spectra\nare produced in a high-statistics analysis on the PACS-CS dynamical gauge-field\nconfigurations with $m_{\\pi} = 411\\textrm{ MeV}$ via variational analyses of\nseveral operator combinations. Despite the introduction of qualitatively\ndifferent interpolating fields, no new states are observed in the energy regime\nof the Roper resonance. This result provides further evidence that the\nlow-lying finite-volume scattering states are not localised, and strengthens\nthe interpretation of the Roper as a coupled-channel, dynamically-generated\nmeson-baryon resonance."
    },
    {
        "anchor": "Hierarchically deflated conjugate residual: We present a progress report on a new class of multigrid solver algorithm\nsuitable for the solution of 5d chiral fermions such as Domain Wall fermions\nand the Continued Fraction overlap. Unlike HDCG \\cite{Boyle:2014rwa}, the\nalgorithm works directly on a nearest neighbour fine operator. The fine\noperator used is Hermitian indefinite, for example $\\Gamma_5 D_{dwf}$, and\nconvergence is achieved with an indefinite matrix solver such as outer\niteration based on conjugate residual. As a result coarse space representations\nof the operator remain nearest neighbour, giving an 8 point stencil rather than\nthe 81 point stencil used in HDCG. It is hoped this may make it viable to\nrecalculate the matrix elements of the little Dirac operator in an HMC\nevolution.",
        "positive": "Strong coupling from non-equilibrium Monte Carlo simulations: We compute the running coupling of non-Abelian gauge theories in the\nSchr\\\"odinger-functional scheme, by means of non-equilibrium Monte Carlo\nsimulations on the lattice."
    },
    {
        "anchor": "Dislocations under gradient flow and their effect on the renormalized\n  coupling: Non-zero topological charge is prohibited in the chiral limit of\ngauge-fermion systems because any instanton would create a zero mode of the\nDirac operator. On the lattice, however, the geometric $Q_\\text{geom}=\\langle\nF{\\tilde F}\\rangle /32\\pi^2$ definition of the topological charge does not\nnecessarily vanish even when the gauge fields are smoothed for example with\ngradient flow. Small vacuum fluctuations (dislocations) not seen by the\nfermions may be promoted to instanton-like objects by the gradient flow. We\ndemonstrate that these artifacts of the flow cause the gradient flow\nrenormalized gauge coupling to increase and run faster. In step-scaling studies\nsuch artifacts contribute a term which increases with volume. The usual $a/L\\to\n0$ continuum limit extrapolations can hence lead to incorrect results. In this\npaper we investigate these topological lattice artifacts in the SU(3) 10-flavor\nsystem with domain wall fermions and the 8-flavor system with staggered\nfermions. Both systems exhibit nonzero topological charge at the strong\ncoupling, especially when using Symanzik gradient flow. We demonstrate how this\nartifact impacts the determination of the renormalized gauge coupling and the\nstep-scaling $\\beta$ function.",
        "positive": "'Bs --> Ds l nu' near zero recoil in and beyond the Standard Model: We compute the normalization of the form factor entering the Bs --> Ds l nu\ndecay amplitude by using numerical simulations of QCD on the lattice. From our\nstudy with Nf=2 dynamical light quarks, and by employing the maximally twisted\nWilson quark action, we obtain in the continuum limit G(1) = 1.052(46). We also\ncompute the scalar and tensor form factors in the region near zero recoil and\nfind f0(t0)/f+(t0)=0.77(2), fT(t0,mb)/f+(t0)=1.08(7), for t0=11.5 GeV^2. These\nlatter results are useful for searching the effects of physics beyond the\nStandard Model in Bs --> Ds l nu decays. Our results for the similar form\nfactors relevant to the non-strange case indicate that the method employed here\ncan be used to achieve the precision determination of the B --> D l nu decay\namplitude as well."
    },
    {
        "anchor": "Quasi-degenerate baryon energy states, the Feynman--Hellmann theorem and\n  transition matrix elements: The standard method for determining matrix elements in lattice QCD requires\nthe computation of three-point correlation functions. This has the disadvantage\nof requiring two large time separations: one between the hadron source and\noperator and the other from the operator to the hadron sink. Here we consider\nan alternative formalism, based on the Dyson expansion leading to the\nFeynman-Hellmann theorem, which only requires the computation of two-point\ncorrelation functions. Both the cases of degenerate energy levels and\nquasi-degenerate energy levels which correspond to diagonal and transition\nmatrix elements respectively can be considered in this formalism. As an example\nnumerical results for the Sigma to Nucleon vector transition matrix element are\npresented.",
        "positive": "The International Lattice Data Grid (ILDG 2.0): We report on status and perspectives of the International Lattice Data Grid.\nILDG was established some twenty years ago as a community-wide initiative to\nenable the sharing of gauge configurations generated by many major lattice\ncollaborations. After a phase in which availability and usage of services had\ndegraded, an effort to modernize and reactivate ILDG 2.0 has been started. The\ninitiative has made important progress and we can look forward to larger and\nfully FAIR data sets becoming available to a wider audience."
    },
    {
        "anchor": "Computing Jet Transport Coefficients On The Lattice: The leading jet transport coefficients $\\hat{q}$ or $\\hat{e}_{2}$ encode\ntransverse or longitudinal momentum broadening of a hard parton traversing a\nhot medium. Understanding their temperature dependence is key to appreciating\nthe observed suppression of high-transverse momentum probes at RHIC or LHC\ncollision energies. We present a first continuum extrapolated result of\n$\\hat{q}$ computed on pure SU(3) lattices with non-trivial temperature\ndependence different from the weak-coupling expectation.\n  We discuss our formalism and its challenges and status in view of obtaining\n$\\hat{e}_{2}$ or of unquenching the calculation. We consider a hard quark\nsubject to a single scattering on the plasma. The transport coefficients are\nfactorized in terms of matrix elements given as integrals of non-local\ngauge-covariant gluon field-strength field-strength correlators. After the\nanalytic continuation to the deep-Euclidean region, the hard scale permits to\nrecast these as a series of local, gauge-invariant operators. The renormalized\nleading-twist term in this expansion is closely related to static quantities,\nand is computed on pure SU(3) lattices ($N_{\\tau}=4,~6,~8,$ and $10$) for a\nwide range of temperatures, ranging from 200MeV < T < 1GeV. Our estimate for\nthe unquenched result in $2+1$-flavor QCD has very similar features.",
        "positive": "Definition and parametrization of non-perturbative effects in quenched\n  QCD: The notion of a non-perturbative effect is ambiguous if it requires the\nsubtraction of a perturbative part defined by a diverging series. A common\nprocedure consists in dropping the order of minimal contribution and the higher\norders. This allows us to isolate very accurately the one-instanton effect for\nthe double-well potential. For the one plaquette gauge theory, an exact\nanalytical expression can be written for the non-perturbative part. We report\nrecent attempts to extend this approach to the average plaquette of quenched\nQCD. Our goal is to express the non-perturbative effects in terms of\nexpressions of the form beta^B exp(-A beta) calculable semi-classically. The\nsituation is complicated by zeroes of the partition function in the complex\n$\\beta$ plane (presumably near 5.75 pm i 0.2). We discuss two methods to\ndescribe the intermediate and large order behavior of the perturbative series.\nOne is inspired by mean field theory (logarithmic specific heat) and reproduces\naccurately the known perturbative series with only two free parameters. A\ndiagrammatic interpretation of this fact is still lacking. The other is based\non infra-red renormalons with a factorial growth showing up at order larger\nthan 20 and a possible effective theory interpretation. These extrapolations\nare compatible with the non-perturbative part of the plaquette being\nproportional to a^4. We propose an exponential parametrization to the\ncorrections to the universal part of the beta function and find results\ncompatible with the suggestion of a^2 corrections made by C. Allton."
    },
    {
        "anchor": "Methods for high-precision determinations of radiative-leptonic decay\n  form factors using lattice QCD: We present a study of lattice-QCD methods to determine the relevant hadronic\nform factors for radiative leptonic decays of pseudoscalar mesons. We provide\nnumerical results for $D_s^+ \\to \\ell^+ \\nu \\gamma$. Our calculation is\nperformed using a domain-wall action for all quark flavors and on a single\nRBC/UKQCD lattice gauge-field ensemble. The first part of the study is how to\nbest control two sources of systematic error inherent in the calculation,\nspecifically the unwanted excited states created by the meson interpolating\nfield, and unwanted exponentials in the sum over intermediate states. Using a\n3d sequential propagator allows for better control over unwanted exponentials\nfrom intermediate states, while using a 4d sequential propagator allows for\nbetter control over excited states. We perform individual analyses of the 3d\nand 4d methods as well as a combined analysis using both methods, and find that\nthe 3d sequential propagator offers good control over both sources of\nsystematic uncertainties for the smallest number of propagator solves. From\nthere, we further improve the use of a 3d sequential propagator by employing an\ninfinite-volume approximation method, which allows us to calculate the relevant\nform factors over the entire allowed range of photon energies. We then study\nimprovements gained by performing the calculation using a different three-point\nfunction, using ratios of three-point functions, averaging over positive and\nnegative photon momentum, and using an improved method for extracting the\nstructure-dependent part of the axial form factor. The optimal combination of\nmethods yields results for the $D_s^+ \\to \\ell^+ \\nu \\gamma$\nstructure-dependent vector and axial form factors in the entire kinematic range\nwith statistical plus fitting uncertainties of order 5%, using 25 gauge\nconfigurations with 64 samples per configuration.",
        "positive": "Setting the Scale Using Baryon Masses with Isospin-Breaking Corrections: We present the status of an ongoing project aimed at the inclusion of\nisospin-breaking corrections arising from the non-degeneracy of the light quark\nmasses and electromagnetic interactions in calculations of the low-lying octet\nand decuplet baryon masses. Our ultimate goal is to perform a precision\ndetermination of the lattice scale including isospin-breaking effects. We apply\nthe perturbative formalism to isospin-symmetric $N_f=2+1$ CLS ensembles. We\nshow results on baryon masses up to leading order in isospin-breaking\ncorrections on two ensembles with $m_\\pi\\approx290\\,\\text{MeV}$ and\n$m_\\pi\\approx215\\,\\text{MeV}$ at a lattice spacing of\n$a\\approx0.076\\,\\text{fm}$."
    },
    {
        "anchor": "Two-flavor QCD Thermodynamics using Anisotropic Lattices: Numerical simulations of full QCD on anisotropic lattices provide a\nconvenient way to study QCD thermodynamics with fixed physics scales and\nreduced lattice spacing errors. We report results from calculations with two\nflavors of dynamical staggered fermions, where all bare parameters and the\nrenormalized anisotropy are kept constant and the temperature is changed in\nsmall steps by varying only the number of time slices. Including results from\nzero-temperature scale setting simulations, which determine the Karsch\ncoefficients, allows for the calculation of the equation of state at finite\ntemperatures.",
        "positive": "String tension and glueball masses of SU(2) QCD from perfect action for\n  monopoles and strings: We study the perfect monopole action as an infrared effective theory of SU(2)\nQCD. It is transformed exactly into a lattice string model. Since the monopole\ninteractions are weak in the infrared SU(2) QCD, the string interactions become\nstrong. The strong coupling expansion of string model shows the quantum\nfluctuation is small. The classical string tension is estimated analytically,\nand we see it is very close to the quantum one in the SU(2) QCD. We also\ndiscuss how to calculate the glueball mass in our model."
    },
    {
        "anchor": "Precision computation of the kaon bag parameter: Indirect CP violation in K \\rightarrow {\\pi}{\\pi} decays plays a central role\nin constraining the flavor structure of the Standard Model (SM) and in the\nsearch for new physics. For many years the leading uncertainty in the SM\nprediction of this phenomenon was the one associated with the nonperturbative\nstrong interaction dynamics in this process. Here we present a fully controlled\nlattice QCD calculation of these effects, which are described by the neutral\nkaon mixing parameter B_K . We use a two step HEX smeared clover-improved\nWilson action, with four lattice spacings from a\\approx0.054 fm to\na\\approx0.093 fm and pion masses at and even below the physical value.\nNonperturbative renormalization is performed in the RI-MOM scheme, where we\nfind that operator mixing induced by chiral symmetry breaking is very small.\nUsing fully nonperturbative continuum running, we obtain our main result\nB_K^{RI}(3.5GeV)=0.531(6)_{stat}(2)_{sys}. A perturbative 2-loop conversion\nyields B_K^{MSbar-NDR}(2GeV)=0.564(6)_{stat}(3)_{sys}(6)_{PT}, which is in good\nagreement with current results from fits to experimental data.",
        "positive": "Abelian monopole or non-Abelian monopole responsible for quark\n  confinement: We have pointed out that the $SU(3)$ Yang-Mills theory has a new way of\nreformulation using new field variables (minimal option), in addition to the\nconventional option adopted by Cho, Faddeev and Niemi (maximal option). The\nreformulation enables us to change the original non-Abelian gauge field into\nthe new field variables such that one of them called the restricted field gives\nthe dominant contribution to quark confinement in the gauge-independent way. In\nthe minimal option, especially, the restricted field is non-Abelian $U(2)$ and\ninvolves the non-Abelian magnetic monopole. In the preceding lattice\nconferences, we have accumulated the numerical evidences for the non-Abelian\nmagnetic-monopole dominance in addition to the restricted non-Abelian field\ndominance for quark confinement supporting the non-Abelian dual\nsuperconductivity using the minimal option for the SU(3) Yang-Mills theory.\nThis should be compared with the maximal option which is a gauge invarient\nversion of the Abelian projection in the maximal Abelian gauge: the restricted\nfield is Abelian $U(1) \\times U(1)$ and involves only the Abelian magnetic\nmonopole, just like the Abelian projection.\n  In this talk, we focus on discriminating between two reformulations, i.e.,\nmaximal and minimal options of $SU(3)$ Yang-Mills theory for quark confinement\nfrom the viewpoint of dual superconductivity. For this purpose, we measure the\ndistribution of the chromoelectric flux connecting a quark and an antiquark and\nthe induced magnetic-monopole current around the flux tube."
    },
    {
        "anchor": "Systematics of Staggered Fermion Spectral Properties and Topology: The spectral properties of a variety of improved staggered operators are\nstudied in quenched QCD. The systematic dependence of the infrared eigenvalue\nspectrum on i) improvement in the staggered operator, ii) improvement in the\ngauge field action, iii) lattice spacing and iv) lattice volume, is analyzed.\nIt is observed that eigenmodes with small eigenvalues and large chirality\nappear as the level of improvement increases or as one approaches the continuum\nlimit. These eigenmodes can be identified as the ``zero modes'' which\ncontribute to the chirality associated, via the index theorem, with the\ntopology of the background gauge field. This gives evidence that staggered\nfermions are sensitive to gauge field topology. After successfully identifying\nthese would-be chiral zero modes, the distribution of the remaining non-chiral\nmodes is compared with the predictions of Random Matrix Theory in different\ntopological sectors. Satisfactory agreement is obtained.",
        "positive": "Lattice artefacts on the Landau gauge gluon propagator from hypercubic\n  tensor representations: Lattice tensor representations are used to investigate the lattice Landau\ngauge gluon propagator for the 4-dimensional pure SU(3) Yang-Mills gauge\ntheory. Due to the different symmetry structure of hypercubic lattices compared\nto the continuum space-time, lattice correlation functions are described by\ndifferent tensor structures. Therefore, form factors describing lattice\ncorrelation functions have, in principle, non-trivial relations with the\ncontinuum counterparts. The use of several tensor bases respecting lattice\nsymmetries, and the analysis of its completeness allows to quantify the\ndeviations of the lattice results from the continuum theory, and also estimate\nthe theoretical uncertainty in the propagator. Furthermore, our analysis tests\ncontinuum based relations with the lattice data and shows that the lattice\nLandau gauge gluon propagator is suitably described by a unique form factor, as\nin the continuum formulation. Additionally, we identified classes of kinematic\nconfigurations where these deviations are minimal and the continuum description\nof lattice tensors is improved."
    },
    {
        "anchor": "Progress in meson-meson scattering at large $N_\\text{c}$: We study the large $N_\\text{c}$ scaling of meson-meson scattering amplitudes\nin a theory with $N_\\text{f}=4$ degenerate quark flavors. We focus on two\ndifferent scattering channels, one having the same quantum numbers as some\nrecently found tetraquark states at LHCb. Using L\\\"uscher's formalism, we study\nthe $N_\\text{c}$ dependence of the scattering phase shift and investigate the\npresence of exotic resonances in the scattering amplitude. We analyze the\nimpact of including two-vector-meson and tetraquark-like operators to extract\nthe finite-volume energies.",
        "positive": "Bold Diagrammatic Monte Carlo Study of $\u03c6^4$ Theory: By incorporating renormalization procedure into Bold Diagrammatic Monte Carlo\n(BDMC), we propose a method for studying quantum field theories in the strong\ncoupling regime. BDMC essentially samples Feynman diagrams using local\nMetropolis-type updates and does not suffer from the sign problem. Applying the\nmethod to three dimensional $\\phi^4$ theory, we analyze the strong coupling\nlimit of the theory and confirm the existence of a nontrivial IR fixed point in\nagreement with prior studies. Interestingly, we find that working with bold\ncorrelation functions as building blocks of the Monte Carlo procedure, renders\nthe scheme convergent and no further resummation method is needed."
    },
    {
        "anchor": "Interpreting Numerical Measurements in Fixed Topological Sectors: For quantum field theories with topological sectors, Monte Carlo simulations\non fine lattices tend to be obstructed by an extremely long auto-correlation\ntime with respect to the topological charge. Then reliable numerical\nmeasurements are feasible only within individual sectors. The challenge is to\nassemble such restricted measurements in a way that leads to a substantiated\napproximation to the fully fledged result, which would correspond to the\ncorrect sampling over the entire set of configurations. We test an approach for\nsuch a topological summation, which was suggested by Brower, Chandrasekharan,\nNegele and Wiese. Under suitable conditions, energy levels and susceptibilities\ncan be obtained to a good accuracy, as we demonstrate for O(N) models, SU(2)\nYang-Mills theory, and for the Schwinger model.",
        "positive": "The Laplacian Gauge Gluon Propagator in SU(N_c): We examine the gluon propagator in the Laplacian gauge in quenched lattice\nQCD as a function of the number of colours. We observe a weak dependence on\n$N_c$ over the whole momentum range. This implies an almost $N_c$-independent\ngluon pole mass in units of the string tension."
    },
    {
        "anchor": "Analytical relation between the Polyakov loop and Dirac eigenvalues in\n  temporally odd-number lattice QCD: We derive an analytical gauge-invariant relation between the Polyakov loop\n$\\langle L_P \\rangle$ and the Dirac eigenvalues $\\lambda_n$ in QCD, i.e.,\n$\\langle L_P \\rangle \\propto \\sum_n \\lambda_n^{N_t -1} \\langle n|\\hat U_4|n\n\\rangle$, on a temporally odd-number lattice, where the temporal lattice size\n$N_t$ is odd. Here, we use an ordinary square lattice with the normal\n(nontwisted) periodic boundary condition for link-variables in the temporal\ndirection. This relation is a Dirac spectral representation of the Polyakov\nloop in terms of Dirac eigenmodes $|n\\rangle$. Because of the factor\n$\\lambda_n^{N_t -1}$ in the Dirac spectral sum, this analytical relation\nindicates negligibly small contribution of low-lying Dirac modes to the\nPolyakov loop in both confined and deconfined phases, while the low-lying Dirac\nmodes are essential for chiral symmetry breaking. Also, we numerically confirm\nthe analytical relation, non-zero finiteness of $\\langle n|\\hat U_4|n \\rangle$,\nand tiny contribution of low-lying Dirac modes to the Polyakov loop in lattice\nQCD simulations. Thus, we conclude that low-lying Dirac modes are not essential\nmodes for confinement, and there is no direct one-to-one correspondence between\nconfinement and chiral symmetry breaking in QCD.",
        "positive": "Persistent homology analysis of deconfinement transition in effective\n  Polyakov-line model: The persistent homology analysis is applied to the effective Polyakov-line\nmodel on a rectangular lattice to investigate the confinement-deconfinement\nnature. The lattice data are mapped onto the complex Polyakov-line plane\nwithout taking the spatial average and then the plane is divided into three\ndomains. This study is based on previous studies for the clusters and the\npercolation properties in lattice QCD, but the mathematical method of the\nanalyses are different. The spatial distribution of the data in the individual\ndomain is analyzed by using the persistent homology to obtain information of\nthe multiscale structure of center clusters. In the confined phase, the data in\nthe three domains show the same topological tendency characterized by the birth\nand death times of the holes which are estimated via the filtration of the\nalpha complexes in the data space, but do not in the deconfined phase. By\nconsidering the configuration averaged ratio of the birth and death times of\nholes, we can construct the nonlocal order-parameter of the\nconfinement-deconfinement transition from the multiscale topological properties\nof center clusters."
    },
    {
        "anchor": "Applying chiral perturbation to twisted mass Lattice QCD: We have explored twisted mass LQCD (tmLQCD) analytically using chiral\nperturbation theory, including discretization effects up to O(a^2), and working\nat next-to-leading (NLO) order in the chiral expansion. In particular we have\nstudied the vacuum structure, and calculated the dependence of pion masses and\ndecay constants on the quark mass, twisting angle and lattice spacing. We give\nexplicit examples for quantities that both are and are not automatically\nimproved at maximal twisting.",
        "positive": "Anisotropic lattice with nonperturbative accuracy: We determine the nonperturbative anisotropic parameter of the gauge action in\nthe quenched approximation with less than 1% accuracy using the Sommer scale\nmeasured by the L\\\"uscher-Weisz algorithm or smearing technique. We also study\nthe nonperturbative O(a)-improvement of the quark action. The bare quark\nanisotropy is determined using the masses from the temporal and spatial\ndirections. For the determination of the $O(a)$ improvement coefficients, we\napply the Schr\\\"odinger functional method."
    },
    {
        "anchor": "Chiral Quark Dynamics and the Ramond-Ramond U(1) Gauge Field: Topological excitations in the QCD vacuum take the form of coherent\ncodimension one sheets with positive and negative sheets juxtaposed in a dipole\nlayer. These sheets may be interpreted as Luscher's \"Wilson bags,\" which are\ndomain walls between discrete quasivacua labelled by a local value of the\n$\\theta$ parameter equal to $2\\pi k$, with $k$ given by the number of units of\nbackground Ramond-Ramond flux. This picture of the vacuum is closely analogous\nto Coleman's description of the 2D massive Schwinger model, where $\\theta$ is\ninterpreted as a background electric field, and a pointlike charged particle is\na domain wall between vacua which differ by one unit of background electric\nflux. The main effect of the Ramond-Ramond U(1) field in low energy QCD\ndynamics is the generation of phenomenologically important contact terms: (1)\nThe dominant contact term in the topological charge correlator which leads to\npositive topological susceptibility, (2) The $\\eta'$ mass insertion, and (3) An\n$SU(N_f)\\times SU(N_f)$ invariant Nambu-Jona Lasinio 4-quark interaction.",
        "positive": "Anderson localization in sigma models: In QCD above the chiral restoration temperature there exists an Anderson\ntransition in the fermion spectrum from localized to delocalized modes. We\ninvestigate whether the same holds for nonlinear sigma models which share\nproperties like dynamical mass generation and asymptotic freedom with QCD. In\nparticular we study the spectra of fermions coupled to (quenched) CP(N-1)\nconfigurations at high temperatures. We compare results in two and three\nspace-time dimensions: in two dimensions the Anderson transition is absent,\nsince all fermion modes are localized, while in three dimensions it is present.\nOur measurements include a more recent observable characterizing level\nspacings: the distribution of ratios of consecutive level spacings."
    },
    {
        "anchor": "Lattice QCD calculation of $K\\to \\ell\u03bd_\\ell \\ell'^+ \\ell'^-$ decay\n  width: We develop a methodology for the computation of the $K\\to \\ell\\nu_\\ell\n\\ell'^+ \\ell'^-$ decay width using lattice QCD and present an exploratory study\nhere. We use a scalar function method to account for the momentum dependence of\nthe decay amplitude and adopt the infinite volume reconstruction method to\nreduce the systematic errors such as the temporal truncation effects and the\nfinite-volume effects. We then perform a four-body phase-space integral to\nobtain the decay width. The only remaining technical problem is the possible\npower-law finite-volume effects associated with the process of $K\\to\\pi\\pi\n\\ell\\nu_\\ell\\to \\ell\\nu_\\ell \\ell'^+ \\ell'^-$, where the intermediate state\ninvolves multiple hadrons. In this work, we use a gauge ensemble of twisted\nmass fermion with a pion mass $m_\\pi=352$ MeV and a nearly-physical kaon mass.\nAt this kinematics, the $\\pi\\pi$ in the intermediate state cannot be on shell\nsimultaneously as $2m_\\pi>m_K$ and the finite-volume effects associated with\n$\\pi\\pi$ state are exponentially suppressed. Using the developed methods\nmentioned above, we calculate the branching ratios for four channels of $K\\to\n\\ell\\nu_\\ell\\ell'^+ \\ell'^-$, and obtain the results comparable to the\nexperimental measurements and ChPT predictions. Our work demonstrates the\ncapability of lattice QCD to improve Standard Model prediction in $K\\to\n\\ell\\nu_\\ell \\ell'^+ \\ell'^-$ decay width.",
        "positive": "Calorons in SU(3) lattice gauge theory: We examine the semiclassical content of SU(3) Yang Mills theory on the\nlattice at finite temperature. Employing the cooling method, a set of classical\nfields is generated from a Monte Carlo ensemble. Various operators are used to\ninspect this set with respect to topological properties. We find pseudoparticle\nfields, so-called caloron solutions, possessing the remarkable features of\n(superpositions of) Kraan-van Baal solutions, i.e. extensions of\nHarrington-Shepard calorons to generic values of the holonomy."
    },
    {
        "anchor": "The 3-loop Beta Function of QCD: Using the background field technique, we calculate the 3-loop beta function\nof lattice $SU(N)$ gauge theories. In the pure gluonic case, we present our\nresults, comparing to those recently obtained by Luescher and Weisz. We also\nprovide a progress report in the case of QCD with Wilson fermions.",
        "positive": "Exploring the phase diagram of finite density QCD at low temperature by\n  the complex Langevin method: Monte Carlo studies of QCD at finite density suffer from the sign problem,\nwhich becomes easily uncontrollable as the chemical potential $\\mu$ is\nincreased even for a moderate lattice size. In this work we make an attempt to\napproach the high density low temperature region by the complex Langevin method\n(CLM) using four-flavor staggered fermions with reasonably small quark mass on\na $8^3 \\times 16$ lattice. Unlike the previous work on a $4^3 \\times 8$\nlattice, the criterion for correct convergence is satisfied within a wide range\nof $\\mu$ without using the deformation technique. In particular, the baryon\nnumber density exhibits a plateau behavior consistent with the formation of\neight baryons, and it starts to grow gradually at some $\\mu$."
    },
    {
        "anchor": "Local correlation among the chiral condensate, monopoles, and color\n  magnetic fields in Abelian projected QCD: Using the lattice gauge field theory, we study the relation among the local\nchiral condensate, monopoles, and color magnetic fields in quantum\nchromodynamics (QCD). First, we investigate idealized Abelian gauge systems of\n1) a static monopole-antimonopole pair and 2) a magnetic flux without\nmonopoles, on a four-dimensional Euclidean lattice. In these systems, we\ncalculate the local chiral condensate on quasi-massless fermions coupled to the\nAbelian gauge field, and find that the chiral condensate is localized in the\nvicinity of the magnetic field. Second, using SU(3) lattice QCD Monte Carlo\ncalculations, we investigate Abelian projected QCD in the maximally Abelian\ngauge, and find clear correlation of distribution similarity among the local\nchiral condensate, monopoles, and color magnetic fields in the Abelianized\ngauge configuration. As a statistical indicator, we measure the correlation\ncoefficient $r$, and find a strong positive correlation of $r \\simeq 0.8$\nbetween the local chiral condensate and an Euclidean color-magnetic quantity\n${\\cal F}$ in Abelian projected QCD. The correlation is also investigated for\nthe deconfined phase in thermal QCD. As an interesting conjecture, like\nmagnetic catalysis, the chiral condensate is locally enhanced by the strong\ncolor-magnetic field around the monopoles in QCD.",
        "positive": "Kaon semileptonic decays near the physical point: The CKM matrix element $|V_{us}|$ can be extracted from the experimental\nmeasurement of semileptonic $K\\to\\pi$ decays. The determination depends on\ntheory input for the corresponding vector form factor in QCD. We present a\npreliminary update on our efforts to compute it in $N_f=2+1$ lattice QCD using\ndomain wall fermions for several lattice spacings and with a lightest pion mass\nof about $170\\,\\mathrm{MeV}$. By using partially twisted boundary conditions we\navoid systematic errors associated with an interpolation of the form factor in\nmomentum-transfer, while simulated pion masses near the physical point reduce\nthe systematic error due to the chiral extrapolation."
    },
    {
        "anchor": "The Maximal Abelian Gauge, Monopoles, and Vortices in SU(3) Lattice\n  Gauge Theory: We report on calculations of the heavy quark potential in SU(3) lattice gauge\ntheory. Full SU(3) results are compared to three cases which involve\ngauge-fixing and projection. All of these start from the maximal abelian gauge\n(MAG), in its simplest form. The first case is abelian projection to U(1)xU(1).\nThe second keeps only the abelian fields of monopoles in the MAG. The third\ninvolves an additional gauge-fixing to the indirect maximal center gauge\n(IMCG), followed by center projection to Z(3). At one gauge\nfixing/configuration, the string tensions calculated from MAG U(1)xU(1), MAG\nmonopoles, and IMCG Z(3) are all less than the full SU(3) string tension. The\nprojected string tensions further decrease, by approximately 10%, when account\nis taken of gauge ambiguities. Comparison is made with corresponding results\nfor SU(2). It is emphasized that the formulation of the MAG is more subtle for\nSU(3) than for SU(2), and that the low string tensions may be caused by the\nsimple MAG form used. A generalized MAG for SU(3) is formulated.",
        "positive": "Magnetic Screening in Hot Non-Abelian Gauge Theory: We analyze the large distance and low-momentum behavior of the magnetic gluon\npropagator of the SU(2) gauge theory at finite temperature. Lattice\ncalculations within the 4-dimensional as well as the effective, dimensionally\nreduced 3-dimensional gauge theories in generalized Landau gauges and MAG show\nthat the magnetic propagator is strongly infrared suppressed in Landau gauges\nbut stays large and finite in MAG. Despite these differences in the\nlow-momentum behavior of the propagator calculated in different gauges the\nmagnetic fields are exponentially screened in all gauges considered. From the\npropagator calculated in maximally Abelian gauge we find for the screening\nmass, m_M = (1.48 +/- 0.17) T at T=2 T_c."
    },
    {
        "anchor": "Lattice Formulation of Two Dimensional Topological Field Theory: We investigate an integrable property and observables of 2 dimensional\nN=(4,4) topological field theory defined on a discrete lattice by using the\n\"orbifolding\" and \"deconstruction\" methods. We show that our lattice model\npossesses the integrability and the partition function reduces to matrix\nintegrals of scalar fields on sites in consequence. We make clear meaningful\ndifferences between the discrete lattice and differentiable manifold, which\nwould be important to a study of topological quantities on the lattice. We also\npropose a new construction of N=(2,2) supersymmetric lattice theory, which is\nrealized by a suitable truncation of scalar fields from the N=(4,4) theory.",
        "positive": "Some Considerations on Chiral Gauge Theories: Some general considerations on the problem of non-perturbative definition of\nChiral Gauge Theories are presented."
    },
    {
        "anchor": "Determination of c and b quark masses: The determination of quark masses has been transformed in the past few years\nby accurate results from realistic lattice QCD. This has meant a range of new\nmethods for both b and c quarks which I will describe along with results from\ncontinuum techniques. The recent improvement in Lattice QCD actions along with\nthe generation of gluon configurations including sea quarks on fine lattices\nhas given us viable methods for handling heavy quarks with relativistic\nactions. This has allowed us for the first time to connect the heavy and light\nsectors through accurate determination of ratios of quark masses, such as\nm_c/m_s. Such ratios enable us to leverage the accuracy of c and b mass\ndeterminations into accurate s and light quark masses. The comparison of quark\nmasses from different methods and formalisms provides a strong test of QCD and\nthe masses themselves are needed in calculations for the cross-sections of\nvarious processes at LHC, for example H to bb.",
        "positive": "FINITE TEMPERATURE PHASE TRANSITION IN QCD WITH STRANGE QUARK: STUDY\n  WITH WILSON FERMIONS ON THE LATTICE: The effect of the strange quark in the finite temperature phase transition of\nQCD is studied on the lattice. Using the one-plaquette gauge action and the\nWilson quark action, the transition in the chiral limit is shown to be\ncontinuous for the case of degenerate two flavors, $N_F=2$, while it is of\nfirst order for $N_F \\geq 3$. For a more realistic case of massless up and down\nquarks and a light strange quark, $N_F=2+1$, clear two state signals are\nobserved both for $m_s \\simeq 150$ and 400 MeV. In contrast to a previous\nresult with staggered quarks, this suggests a first order transition in the\nreal world. In order to see the implication of these results to the continuum\nlimit, we started to study these issues using improved actions. First results\nusing a RG improved gauge action combined with the standard Wilson quark is\npresented for the case of $N_F=2$: With this action the finite temperature\ntransition is shown to be continuous in the chiral limit confirming the result\nof the standard action. Furthermore, not like the case of the standard action\nwhere lattice artifacts make the transition once very strong at intermediate\nvalues of the hopping parameter $K$ on $N_t=4$ and 6 lattices, a smooth\ncrossover is found for the improved action when we increase $1/K-1/K_c$, in\naccord with a naive expectation about the fate of second order chiral\ntransition at finite $m_q$."
    },
    {
        "anchor": "Can stochastic quantization evade the sign problem? -- the relativistic\n  Bose gas at finite chemical potential: A nonperturbative study of field theories with a complex action, such as QCD\nat finite baryon density, is difficult due to the sign problem. We show that\nthe relativistic Bose gas at finite chemical potential has a sign and `Silver\nBlaze' problem, similar to QCD. We then apply stochastic quantization and\ncomplex Langevin dynamics to study this theory with nonperturbative lattice\nsimulations. Independence of chemical potential at small and a transition to a\ncondensed phase at large chemical potential are found. Lattices of size N^4,\nwith N=4,6,8,10, are used. We show that the sign problem is severe, however, we\nfind that it has no negative effect using this approach. This improves the\nprospects of applying stochastic quantization to QCD at nonzero density.",
        "positive": "Search of QCD phase transition points in the canonical approach of the\n  NJL model: We study the Lee-Yang zeros in the canonical approach to search phase\ntransition points at finite temperature and density in the Nambu-Jona-Lasinio\n(NJL) model as an effective model of QCD. The canonical approach is a promising\nmethod to avoid the sign problem in lattice QCD at finite density. We find that\na set of Lee-Yang zeros computed with finite degrees of freedom can be\nextrapolated to those with infinite degrees of freedom, providing the correct\nphase transition point. We propose the present method as a useful method for\nactual lattice simulations for QCD."
    },
    {
        "anchor": "Three-particle quantization condition in a finite volume: 1. The role of\n  the three-particle force: Using non-relativistic effective Lagrangians in the particle-dimer picture,\nwe rederive the expression for the energy shift of a loosely bound\nthree-particle bound state of identical bosons in the unitary limit. The\neffective field theory formalism allows us to investigate the role of the\nthree-particle force, which has not been taken into account in the earlier\ntreatment of the problem. Moreover, we are able to relax the requirement of the\nunitary limit of infinite scattering length and demonstrate a smooth transition\nfrom the weakly bound three-particle state to a two-particle bound state of a\nparticle and a deeply bound dimer.",
        "positive": "$\u039b_b \\to \u039b_c^*(2595,2625)\\ell^-\\bar\u03bd$ form factors from\n  lattice QCD: We present the first lattice-QCD determination of the form factors describing\nthe semileptonic decays $\\Lambda_b \\to \\Lambda_c^*(2595)\\ell^-\\bar{\\nu}$ and\n$\\Lambda_b \\to \\Lambda_c^*(2625)\\ell^-\\bar{\\nu}$, where the $\\Lambda_c^*(2595)$\nand $\\Lambda_c^*(2625)$ are the lightest charm baryons with $J^P=\\frac12^-$ and\n$J^P=\\frac32^-$, respectively. These decay modes provide new opportunities to\ntest lepton flavor universality and also play an important role in global\nanalyses of the strong interactions in $b\\to c$ semileptonic decays. We\ndetermine the full set of vector, axial vector, and tensor form factors for\nboth decays, but only in a small kinematic region near the zero-recoil point.\nThe lattice calculation uses three different ensembles of gauge-field\nconfigurations with $2+1$ flavors of domain-wall fermions, and we perform\nextrapolations of the form factors to the continuum limit and physical pion\nmass. We present Standard-Model predictions for the differential decay rates\nand angular observables. In the kinematic region considered, the differential\ndecay rate for the $\\frac12^-$ final state is found to be approximately 2.5\ntimes larger than the rate for the $\\frac32^-$ final state. We also test the\ncompatibility of our form-factor results with zero-recoil sum rules."
    },
    {
        "anchor": "The Ademollo-Gatto theorem for lattice semileptonic decays: We present the results of the calculation of the Kl3 semileptonic form factor\nat zero momentum transfer, f(0), obtained at one-loop in partially quenched\nChiral Perturbation Theory (with either Nf=2, or Nf=3, and with generic valence\nand sea quark masses). We show that for Nf=2, when the masses of the valence\nand sea light quarks are equal, the correction is of the order (MK^2-Mpi^2)^3.\nThe formulae presented here can be useful for the mass extrapolation of the\nresults obtained in lattice simulations to the physical point.",
        "positive": "Some comments on Laplacian gauge fixing: Laplacian gauge fixing was introduced to find a unique representative of the\ngauge orbit, which on the lattice could be implemented by a ``finite''\nalgorithm. What was still lacking was a perturbative formulation of this gauge,\nwhich will be presented here. However, renormalizability is still to be\ndemonstrated. For torodial and spherical geometries a detailed comparison with\nthe Landau (or Coulomb) gauge will be made."
    },
    {
        "anchor": "Ising model as Wilson-Majorana Fermions: We show the equivalence of the 2D Ising model to standard free Euclidean\nlattice fermions of the Wilson Majorana type. The equality of the loop\nrepresentations for the partition functions of both systems is established\nexactly for finite lattices with well-defined boundary conditions. The\nhoneycomb lattice is particularly simple in this context and therefore\ndiscussed first and only then followed by the more familiar square lattice\ncase.",
        "positive": "Numerical properties of staggered quarks with a taste-dependent mass\n  term: The numerical properties of staggered Dirac operators with a taste-dependent\nmass term proposed by Adams [1,2] and by Hoelbling [3] are compared with those\nof ordinary staggered and Wilson Dirac operators. In the free limit and on\n(quenched) interacting configurations, we consider their topological\nproperties, their spectrum, and the resulting pion mass. Although we also\nconsider the spectral structure, topological properties, locality, and\ncomputational cost of an overlap operator with a staggered kernel, we call\nattention to the possibility of using the Adams and Hoelbling operators without\nthe overlap construction. In particular, the Hoelbling operator could be used\nto simulate two degenerate flavors without additive mass renormalization, and\nthus without fine-tuning in the chiral limit."
    },
    {
        "anchor": "B meson leptonic decay constant with quenched lattice NRQCD: We present a lattice NRQCD study of the B meson decay constant in the\nquenched approximation with emphasis given to the scaling behavior. The NRQCD\naction and the heavy-light axial current we use include all terms of order 1/M\nand the perturbative $O(\\alpha_s a)$ and $O(\\alpha_s/M)$ corrections. Using\nsimulations at three value of couplings $\\beta$=5.7, 5.9 and 6.1 on lattices of\nsize $12^3\\times 32, 16^3\\times 48$ and $24^3\\times 64$, we find no significant\n$a$ dependence in $f_B$ if the $O(\\alpha_s a)$ correction is included in the\naxial current. We obtain $f_B = 167(7)(15)$ MeV, $f_{B_s}=\n191(4)(17)(^{+4}_{-0})$ MeV and $f_{B_s}/f_B =1.15(3)(1)(^{+3}_{-0})$, with the\nfirst error being statistical, the second systematic, and the third due to\nuncertainty of strange quark mass, while quenching errors being not included.",
        "positive": "Deconfinement, Screening and Abelian Projection at Finite Temperature: The behavior of static sources transforming according to different\nirreducible representations of the gauge group is studied in the context of\nfinite temperature lattice gauge theory. We combine analytical and numerical\napproaches to extract information about confinement and screening both at low\ntemperatures, and around the deconfinement phase transition. The idea that\nabelian projection in the Maximally Abelian Gauge reproduces the most important\nfeatures of confinement and screening is tested at a quantitative level in\nthese finite-T theories. Our results show that while this abelian projection\nprovides correct qualitative features, it fails at a detailed quantitative\nlevel."
    },
    {
        "anchor": "QCD AT FINITE BARYON DENSITY WITH t-ASYMMETRIC FERMIONS: Susskind's continuous-time fermions, with two flavours, can be latticized\nusing a one-sided time derivative. We are presently investigating the\ninteracting case, where we hope to find the onset at finite $\\mu$ at the right\nplace due to the reduced number of flavours. As for these fermions there is\nonly a discrete chiral symmetry left over, the lightness of pions in the broken\nphase has to be investigated.",
        "positive": "The Static Penta-quark Potential in Lattice QCD: We perform the first study for the static penta-quark (5Q) potential in\nlattice QCD with $\\beta$=6.0 and $16^3 \\times 32$ at the quenched level.\nAccurate results of the 5Q potential are extracted from the 5Q Wilson loop\nusing the smearing method, which enhances the ground-state component. The\ntetra-quark potential for the $\\rm QQ$-$\\rm {\\bar Q}{\\bar Q}$ system is also\nstudied in lattice QCD. The multi-quark potentials are found to be well\ndescribed as a sum of the one-gluon-exchange Coulomb term and the multi-Y\nlinear confinement term based on the flux-tube picture."
    },
    {
        "anchor": "The chromomagnetic operator on the lattice: We study matrix elements of the \"chromomagnetic\" operator on the lattice.\nThis operator is contained in the strangeness-changing effective Hamiltonian\nwhich describes electroweak effects in the Standard Model and beyond.\n  Having dimension 5, the chromomagnetic operator is characterized by a rich\npattern of mixing with other operators of equal and lower dimensionality,\nincluding also non gauge invariant quantities; it is thus quite a challenge to\nextract from lattice simulations a clear signal for the hadronic matrix\nelements of this operator.\n  We compute all relevant mixing coefficients to one loop in lattice\nperturbation theory; this necessitates calculating both 2-point\n(quark-antiquark) and 3-point (gluon-quark-antiquark) Green's functions at\nnonzero quark masses. We use the twisted mass lattice formulation, with\nSymanzik improved gluon action.\n  For a comprehensive presentation of our results, along with detailed\nexplanations and a more complete list of references, we refer to our\nforthcoming publication [1].",
        "positive": "Tricritical scaling at the N_t=6 chiral phase transition for 2 flavour\n  lattice QCD with staggered quarks: We have simulated lattice QCD directly in the chiral limit of zero quark mass\nby adding an additional, irrelevant 4-fermion interaction to the standard\naction. Using lattices having temporal extent of six and spatial extents of\ntwelve and eighteen, we find that the theory with 2 massless staggered quark\nflavors has a second order finite temperature phase transition. The critical\nexponents $\\beta_{mag}$, $\\delta$ and $\\nu$ are measured and favour tricritical\nbehaviour over that expected by universality arguments. The pion screening mass\nis consistent with zero below the transition, but is degenerate with the\nnonzero $\\sigma(f_0)$ mass above the transition, indicating the restoration of\nchiral symmetry."
    },
    {
        "anchor": "Status of the Finite Temperature Electroweak Phase Transition on the\n  Lattice: I review the status of non-perturbative investigations of the finite\ntemperature electroweak phase transition by means of lattice simulations.",
        "positive": "Towards the finite-volume spectrum of the Roper resonance: The finite-volume energy levels corresponding to the Roper resonance based on\na two-flavor chiral effective Lagrangian at leading one-loop order are\ninvestigated. It is shown that the Roper mass can be extracted from these\nlevels for not too large lattice volumes. Further, to include three-body $N \\pi\n\\pi$ dynamics, a non-relativistic effective field theory for the Roper\nresonance within a covariant particle-dimer picture is introduced. This\nparticle-dimer approach is a suitable framework to investigate three-particle\nscattering relevant for the Roper channel. The appearing dimer fields are\nanalyzed, the energy levels of the Roper resonance in a finite volume are\ncalculated and compared to the results from the chiral effective Lagrangian."
    },
    {
        "anchor": "Properties of a New Class of Lattice Dirac Operators: A new class of lattice Dirac operators $D$ have been recently proposed on the\nbasis of the generalized Ginsparg-Wilson relation, $\\gamma_5(\\gamma_5 D) +\n(\\gamma_5 D)\\gamma_5 =2a^{2k+1}(\\gamma_5 D)^{2k+2}$, where $k$ is a\nnon-negative integer. We discuss the index theorem and locality properties for\nthis general class of lattice Dirac operators.",
        "positive": "The strong-coupling limit of lattice Landau gauge: We report on our recent study of the gluon and ghost propagators of pure\nSU(2) minimal lattice Landau gauge in the strong-coupling limit. In this limit,\nwe find evidence of the conformal infrared behaviour of these propagators as\npredicted by functional continuum methods. However, in the strong-coupling\nlimit this happens for lattice momenta with a^2q^2>1, in units of the lattice\nspacing a. Deviations from conformal scaling for a^2q^2<1 are well\nparameterised by a transverse gluon mass. A comparison of various lattice\ndefinitions of gauge potentials, all equivalent in the continuum limit, shows\nthat (a) both the critical exponent and coupling can be extracted unambiguously\nfrom the high-momentum data in the strong-coupling limit, in good agreement\nwith the continuum predictions; but that on the other hand (b) the massive\nbranch depends on the definition of lattice gluon fields and is thus not\nunambiguously defined. We demonstrate that this ambiguity is also present in\nthe low-momentum region for commonly used values of the lattice coupling in\nSU(2)."
    },
    {
        "anchor": "Phase transitions in a gas of anyons: We continue our numerical Monte Carlo simulation of a gas of closed loops on\na 3 dimensional lattice, however now in the presence of a topological term\nadded to the action corresponding to the total linking number between the\nloops. We compute the linking number using certain notions from knot theory.\nAdding the topological term converts the particles into anyons. Using the\ncorrespondence that the model is an effective theory that describes the\n2+1-dimensional Abelian Higgs model in the asymptotic strong coupling regime,\nthe topological linking number simply corresponds to the addition to the action\nof the Chern-Simons term. We find the following new results. The system\ncontinues to exhibit a phase transition as a function of the anyon mass as it\nbecomes small \\cite{mnp}, although the phases do not change the manifestation\nof the symmetry. The Chern-Simons term has no effect on the Wilson loop, but it\ndoes affect the {\\rm '}t Hooft loop. For a given configuration it adds the\nlinking number of the 't Hooft loop with all of the dynamical vortex loops to\nthe action. We find that both the Wilson loop and the 't Hooft loop exhibit a\nperimeter law even though there are no massless particles in the theory, which\nis unexpected.",
        "positive": "The Rome Approach to Chirality: Some general considerations on the problem of non perturbative definition of\nChiral Gauge Theories are presented and exemplified within the particular\nproposal known as the Rome Approach."
    },
    {
        "anchor": "Analysis of topological structure of the QCD vacuum with overlap-Dirac\n  operator eigenmode: Using the eigenmodes of the overlap-Dirac operator, we study the topological\nstructure of the QCD vacuum. We investigate the space-time profile of the\nlow-lying eigenmodes and their contribution to the vacuum action density and\nchiral condensate under the existence of static color sources. We demonstrate\nthat the low-lying Dirac eigenmode shows the flux-tube structure, which\nsuggests the relevance to confinement. We also analyze the chiral condensate in\nthe flux-tube. Chiral symmetry is partially restored inside the flux, and the\nreduction of the condensate is about 20% at the center of the tube.",
        "positive": "Two-dimensional N=(2,2) super Yang-Mills theory on computer: We carry out preliminary numerical study of Sugino's lattice formulation\n\\cite{Sugino:2004qd,Sugino:2004qdf} of the two-dimensional $\\mathcal{N}=(2,2)$\nsuper Yang-Mills theory (2d $\\mathcal{N}=(2,2)$ SYM) with the gauge group\n$\\SU(2)$. The effect of dynamical fermions is included by re-weighting a\nquenched ensemble by the pfaffian factor. It appears that the complex phase of\nthe pfaffian due to lattice artifacts and flat directions of the classical\npotential are not problematic in Monte Carlo simulation. Various one-point\nsupersymmetric Ward-Takahashi (WT) identities are examined for lattice spacings\nup to $a=0.5/g$ with the fixed physical lattice size $L=4.0/g$, where $g$\ndenotes the gauge coupling constant in two dimensions. WT identities implied by\nan exact fermionic symmetry of the formulation are confirmed in fair accuracy\nand, for most of these identities, the quantum effect of dynamical fermions is\nclearly observed. For WT identities expected only in the continuum limit, the\nresults seem to be consistent with the behavior expected from supersymmetry,\nalthough we do not see clear distintion from the quenched simulation. We\nmeasure also the expectation values of renormalized gauge-invariant bi-linear\noperators of scalar fields."
    },
    {
        "anchor": "Ideal Walking Dynamics via a Gauged NJL Model: According to the Ideal Walking Technicolor paradigm large mass anomalous\ndimensions arise in gauged Nambu--Jona-Lasinio (NJL) models when the\nfour-fermion coupling is sufficiently strong to induce spontaneous symmetry\nbreaking in an otherwise conformal gauge theory. We therefore study the $SU(2)$\ngauged NJL model with two adjoint fermions using lattice simulations. The model\nis in an infrared conformal phase at small NJL coupling while it displays a\nchirally broken phase at large NJL couplings. In the infrared conformal phase\nwe find that the mass anomalous dimension varies with the NJL coupling reaching\n$\\gamma_m \\sim 1$ close to the chiral symmetry breaking transition, de facto\nmaking the present model the first explicit realization of the Ideal Walking\nscenario.",
        "positive": "From C to Parton Sea: Bjorken-x Dependence of the PDFs: Studying the structure of nucleons is not only important to understanding the\nstrong interactions of quarks and gluons, but also to improving the precision\nof new-physics searches. Since a broad class of experiments, including the LHC\nand dark-matter detection, require Standard-Model backgrounds with parton\ndistribution functions (PDFs) as inputs for disentangling SM contributions from\npotential new physics. For a long time, lattice calculations of the PDFs (as\nwell as many hadron structures) has been limited to the first few moments. In\nthis talk, we present a first direct calculation of the Bjorken-x dependence of\nthe PDFs using Large-Momentum Effective Theory (LaMET). An exploratory study of\nthe antiquark/sea flavor asymmetry of these distributions will be discussed.\nThis breakthrough opens an exciting new frontier calculating more complicated\nquantities, such as gluon structure and transverse-momentum dependence, which\nwill complement existing theoretical programs for the upcoming Electron-Ion\nCollider (EIC) or Large Hadron-Electron Collider (LHeC)."
    },
    {
        "anchor": "Lattice NRQCD study on in-medium bottomonium spectra using a novel\n  Bayesian reconstruction approach: We present recent results on the in-medium modification of S- and P-wave\nbottomonium states around the deconfinement transition. Our study uses lattice\nQCD with $N_f=2+1$ light quark flavors to describe the non-perturbative thermal\nQCD medium between $140$MeV$<T<249$MeV and deploys lattice regularized\nnon-relativistic QCD (NRQCD) effective field theory to capture the physics of\nheavy quark bound states immersed therein. The spectral functions of the\n$^3S_1$ $(\\Upsilon)$ and $^3P_1$ $(\\chi_{b1})$ bottomonium states are extracted\nfrom Euclidean time Monte Carlo simulations using a novel Bayesian\nprescription, which provides higher accuracy than the Maximum Entropy Method.\nBased on a systematic comparison of interacting and free spectral functions we\nconclude that the ground states of both the S-wave $(\\Upsilon)$ and P-wave\n$(\\chi_{b1})$ channel survive up to $T=249$MeV. Stringent upper limits on the\nsize of the in-medium modification of bottomonium masses and widths are\nprovided.",
        "positive": "Density Matrix Renormalization Group Approach to the Massive Schwinger\n  Model: The massive Schwinger model is studied, using a density matrix\nrenormalization group approach to the staggered lattice Hamiltonian version of\nthe model. Lattice sizes up to 256 sites are calculated, and the estimates in\nthe continuum limit are almost two orders of magnitude more accurate than\nprevious calculations. Coleman's picture of `half-asymptotic' particles at\nbackground field (theta = pi) is confirmed. The predicted phase transition at\nfinite fermion mass (m/g) is accurately located, and demonstrated to belong in\nthe 2D Ising universality class."
    },
    {
        "anchor": "Toward $N$ to $N\u03c0$ matrix elements from lattice QCD: QCD matrix elements of axial and vector currents between nucleons are\nrequired for the Monte Carlo reconstruction of the energy of neutrinos that are\ndetected in long baseline oscillation experiments in the quasi-elastic regime.\nThe cleanest approach for determining the axial matrix elements is lattice QCD.\nHowever, the extraction of these from the corresponding correlation functions\nis complicated by very large excited state contributions, that are related to\ntransitions from the nucleon to a nucleon-pion pair. In this pilot study with a\npion mass $m_\\pi = 429~ \\mathrm{MeV}$, we demonstrate for the first time that\nthese contributions can be removed by including five-(anti)quark operators into\nthe basis of interpolators used to create the nucleon. The same techniques will\nbe needed to compute transition matrix elements between the nucleon and\nnucleon-pion scattering states that are relevant in the resonance production\nregime.",
        "positive": "Deformed matrix models, supersymmetric lattice twists and N=1/4\n  supersymmetry: A manifestly supersymmetric nonperturbative matrix regularization for a\ntwisted version of N=(8,8) theory on a curved background (a two-sphere) is\nconstructed. Both continuum and the matrix regularization respect four exact\nscalar supersymmetries under a twisted version of the supersymmetry algebra. We\nthen discuss a succinct Q=1 deformed matrix model regularization of N=4 SYM in\nd=4, which is equivalent to a non-commutative $A_4^*$ orbifold lattice\nformulation. Motivated by recent progress in supersymmetric lattices, we also\npropose a N=1/4 supersymmetry preserving deformation of N=4 SYM theory on\n$\\R^4$. In this class of N=1/4 theories, both the regularized and continuum\ntheory respect the same set of (scalar) supersymmetry. By using the equivalence\nof the deformed matrix models with the lattice formulations, we give a very\nsimple physical argument on why the exact lattice supersymmetry must be a\nsubset of scalar subalgebra. This argument disagrees with the recent claims of\nthe link approach, for which we give a new interpretation."
    },
    {
        "anchor": "The lattice gradient flow at tree level: The cut-off effects of the lattice gradient flow -- often called Wilson flow\n-- are calculated on a periodic 4-torus at leading order in the gauge coupling.\nA large class of discretizations is considered which includes all frequently\nused cases in practice. It is shown how the results lead to a smoother\ncontinuum extrapolation for the beta-function of SU(3) gauge theory with N_f =\n4 flavors of fermions.",
        "positive": "SU(2) QCD in the Path Representation: General Formalism and Mandelstam\n  Indentities: We introduce a path-dependent hamiltonian representation (the path\nrepresentation) for SU(2) with fermions in 3 + 1 dimensions. The\ngauge-invariant operators and hamiltonian are realized in a Hilbert space of\nopen path and loop functionals. We obtain two new types of Mandelstam\nidentities one that connects open path operators with loop operators and other\ninvolving the end points of the paths."
    },
    {
        "anchor": "Highly Improved Staggered Quarks on the Lattice, with Applications to\n  Charm Physics: We use perturbative Symanzik improvement to create a new staggered-quark\naction (HISQ) that has greatly reduced one-loop taste-exchange errors, no\ntree-level order a^2 errors, and no tree-level order (am)^4 errors to leading\norder in the quark's velocity v/c. We demonstrate with simulations that the\nresulting action has taste-exchange interactions that are at least 3--4 times\nsmaller than the widely used ASQTAD action. We show how to estimate errors due\nto taste exchange by comparing ASQTAD and HISQ simulations, and demonstrate\nwith simulations that such errors are no more than 1% when HISQ is used for\nlight quarks at lattice spacings of 1/10 fm or less. The suppression of (am)^4\nerrors also makes HISQ the most accurate discretization currently available for\nsimulating c quarks. We demonstrate this in a new analysis of the psi-eta_c\nmass splitting using the HISQ action on lattices where a m_c=0.43 and 0.66,\nwith full-QCD gluon configurations (from MILC). We obtain a result of~111(5)\nMeV which compares well with experiment. We discuss applications of this\nformalism to D physics and present our first high-precision results for D_s\nmesons.",
        "positive": "Quark mass dependence of nucleon mass and axial-vector coupling constant: We present an updated analysis of the quark mass dependence of the nucleon\nmass and nucleon axial-vector coupling g_A, comparing different formulations of\nSU(2) Baryon Chiral Effective Field Theory, with and without explicit delta\n(1232) degrees of freedom. We discuss the outcome of the corresponding\ninterpolations between lattice QCD data and the physical values for these two\nnucleon observables. It turns out that in order to obtain successful\ninterpolating functions at one-loop order, the inclusion of explicit delta\n(1232) degrees of freedom is not decisive for the nucleon mass but crucial for\ng_A. A chiral extrapolation of recent lattice results by the LHP collaborations\nis also shown."
    },
    {
        "anchor": "The three-dimensional, three-state Potts Model in an External Field: We analyze the critical behaviour of the three-dimensional, three-state Potts\nmodel in the presence of an external ordering field. From a finite size scaling\nanalysis on lattices of size up to 70**3 we determine the critical endpoint of\nthe line of first order phase transitions as (b_c, h_c) =(0.54938(2),\n0.000775(10)). We determine the relevant temperature like and symmetry breaking\ndirections at this second order critical point and explicitly verify that it is\nin the universality class of the three-dimensional Ising model.",
        "positive": "A lattice determination of Sigma - Lambda mixing: Isospin breaking effects in baryon octet (and decuplet) masses are due to a\ncombination of up and down quark mass differences and electromagnetic effects\nand lead to small mass splittings. Between the Sigma and Lambda this mass\nsplitting is much larger, this being mostly due to their different\nwavefunctions. However when isospin is broken, there is a mixing between\nbetween these states. We describe the formalism necessary to determine the QCD\nmixing matrix and hence find the mixing angle and mass splitting between the\nSigma and Lambda particles due to QCD effects."
    },
    {
        "anchor": "Lattice QCD at maximal twist: In this review we discuss the general features of maximally twisted lattice\nQCD. In particular, we illustrate how automatic O(a) improvement can be\nachieved and how it is possible to set up a lattice regularization scheme where\nthe problem of wrong chirality mixing (be it finite or infinite) affecting the\ncomputation of the matrix elements of the CP-conserving effective weak\nHamiltonian is neatly avoided, while having at the same time a positive\ndeterminant even for non-degenerate quark pairs. The question of reducing the\nlarge cutoff effects that appear when the quark mass tends to zero as a\nconsequence of parity and iso-spin breaking in the action is also addressed. It\nis shown that such dangerous lattice artifacts are strongly suppressed if the\nclover term is added to the action or, alternatively, the critical mass is\nchosen so as to enforce the restoration of parity.",
        "positive": "Lattice results for the longitudinal spin structure and color forces on\n  quarks in a nucleon: Using lattice QCD, we calculate the twist-2 contribution $a_2$ to the third\nMellin moment of the spin structure functions $g_1$ and $g_2$ in the nucleon.\nIn addition we evaluate the twist-3 contribution $d_2$. Our computations make\nuse of $N_f=2+1$ gauge field ensembles generated by the Coordinated Lattice\nSimulations (CLS) effort. Neglecting quark-line disconnected contributions we\nobtain as our best estimates $a_2^{(p)}= 0.069(17)$, $d_2^{(p)}= 0.0105(68)$\nand $a_2^{(n)}= 0.0068(88)$, $d_2^{(n)}= -0.0009(70)$ for the proton and the\nneutron, respectively, where we use the normalizations given in Eqs. (58) and\n(59). While the $a_2$ results have been converted to the\n$\\overline{\\mathrm{MS}}$ scheme using three-loop perturbation theory, the\nnumbers for $d_2$ are given in the regularization independent momentum\nsubtraction (RI$^\\prime$-MOM) scheme, i.e., the conversion has been performed\nonly in tree-level perturbation theory. The $d_2$ results can be interpreted as\ncorresponding to a transverse color Lorentz force on a quark in a transversely\npolarized proton of size $F^{(u)} = 116(61)$ MeV/fm and $F^{(d)} = -38(66)$\nMeV/fm for $u$ and $d$ quarks, respectively. The error estimates quoted include\nstatistical and systematic uncertainties added in quadrature."
    },
    {
        "anchor": "A Regularization of Quantum Gravity: We re-examine results of the Liouville theory and provide arguments that a\n{\\it negative} bare cosmological constant is essential to define\ntwo-dimensional quantum gravity. From this we are naturally led to a\nregularization of quantum gravity within the Regge approach such that it is\ndescribed by small fluctuations around equilateral triangles, whose average\nlink length approaches zero in the continuum limit. We investigate a model\nbased on this idea numerically and present evidence for the desired long-range\ncorrelations. Interestingly, the approach might generalize to higher\ndimensions. The picture of an inflated balloon, which is often used to\ndemonstrate the properties of an expanding classical universe, seems to be\nvaluable to understand quantum gravity as well.",
        "positive": "Tensor network simulation of the (1+1)-dimensional $O(3)$ nonlinear\n  $\u03c3$-model with $\u03b8=\u03c0$ term: We perform a tensor network simulation of the (1+1)-dimensional $O(3)$\nnonlinear $\\sigma$-model with $\\theta=\\pi$ term. Within the Hamiltonian\nformulation, this field theory emerges as the finite-temperature partition\nfunction of a modified quantum rotor model decorated with magnetic monopoles.\nUsing the monopole harmonics basis, we derive the matrix representation for\nthis modified quantum rotor model, which enables tensor network simulations. We\nemploy our recently developed continuous matrix product operator method [Tang\net al., Phys. Rev. Lett. 125, 170604 (2020)] to study the finite-temperature\nproperties of this model and reveal its massless nature. The central charge as\na function of the coupling constant is directly extracted in our calculations\nand compared with field theory predictions."
    },
    {
        "anchor": "Free energies of heavy quarks in full-QCD lattice simulations with\n  Wilson-type quark action: The free energy between a static quark and an antiquark is studied by using\nthe color-singlet Polyakov-line correlation at finite temperature in lattice\nQCD with 2+1 flavors of improved Wilson quarks. From the simulations on $32^3\n\\times 12$, 10, 8, 6, 4 lattices in the high temperature phase, based on the\nfixed scale approach, we find that, the heavy-quark free energies at short\ndistance converge to the heavy-quark potential evaluated from the Wilson loop\nat zero temperature, in accordance with the expected insensitivity of short\ndistance physics to the temperature. At long distance, the heavy-quark free\nenergies approach to twice the single-quark free energies, implying that the\ninteraction between heavy quarks is screened.\n  The Debye screening mass obtained from the long range behavior of the free\nenergy is compared with the results of thermal perturbation theory.",
        "positive": "The chiral critical line of N_f=2+1 QCD at zero and non-zero baryon\n  density: We present numerical results for the location of the chiral critical line at\nfinite temperature and zero and non-zero baryon density for QCD with N_f=2+1\nflavours of staggered fermions on lattices with temporal extent N_t=4. For\ndegenerate quark masses, we compare our results obtained with the exact RHMC\nalgorithm with earlier, inexact R-algorithm results and find a reduction of 25%\nin the critical quark mass, for which the first order phase transition changes\nto a smooth crossover. Extending our analysis to non-degenerate quark masses,\nwe map out the chiral critical line up to the neighbourhood of the physical\npoint, which we confirm to be in the crossover region. Our data are consistent\nwith a tricritical point at a strange quark mass of ~500 MeV. Finally, we\ninvestigate the shift of the critical line with finite baryon density, by\nsimulating with an imaginary chemical potential for which there is no sign\nproblem. We observe this shift to be very small or, conversely, the critical\nendpoint \\mu^c(m_{u,d},m_s) to be extremely quark mass sensitive. Moreover, the\nsign of this shift is opposite to standard expectations. If confirmed on a\nfiner lattice, it implies the absence of a critical endpoint or phase\ntransition for chemical potentials \\mu_B < 500 MeV. We thus argue that finer\nlattices are required to settle even the qualitative features of the QCD phase\ndiagram."
    },
    {
        "anchor": "A non-perturbative exploration of the high energy regime in\n  $N_\\text{f}=3$ QCD: Using continuum extrapolated lattice data we trace a family of running\ncouplings in three-flavour QCD over a large range of scales from about 4 to 128\nGeV. The scale is set by the finite space time volume so that recursive finite\nsize techniques can be applied, and Schr\\\"odinger functional (SF) boundary\nconditions enable direct simulations in the chiral limit. Compared to earlier\nstudies we have improved on both statistical and systematic errors. Using the\nSF coupling to implicitly define a reference scale $1/L_0\\approx 4$ GeV through\n$\\bar{g}^2(L_0) =2.012$, we quote $L_0 \\Lambda^{N_{\\rm f}=3}_{\\overline{\\rm\nMS}} =0.0791(21)$. This error is dominated by statistics; in particular, the\nremnant perturbative uncertainty is negligible and very well controlled, by\nconnecting to infinite renormalization scale from different scales $2^n/L_0$\nfor $n=0,1,\\ldots,5$. An intermediate step in this connection may involve any\nmember of a one-parameter family of SF couplings. This provides an excellent\nopportunity for tests of perturbation theory some of which have been published\nin a letter [1]. The results indicate that for our target precision of 3 per\ncent in $L_0 \\Lambda^{N_{\\rm f}=3}_{\\overline{\\rm MS}}$, a reliable estimate of\nthe truncation error requires non-perturbative data for a sufficiently large\nrange of values of $\\alpha_s=\\bar{g}^2/(4\\pi)$. In the present work we reach\nthis precision by studying scales that vary by a factor $2^5= 32$, reaching\ndown to $\\alpha_s\\approx 0.1$. We here provide the details of our analysis and\nan extended discussion.",
        "positive": "Reply to A. Patrascioiu's and E. Seiler's Comment on our paper\n  \"Percolation properties of the 2D Heisenberg model\": Reply to comment appeared on hep-lat/9912014."
    },
    {
        "anchor": "A cross-channel study of pion scattering from lattice QCD: We use a chiral model for pion interactions, in the inverse amplitude\nformalism, to perform a simultaneous analysis of lattice QCD results for\npion-pion scattering in all three isospin channels. The input is the\nfinite-volume two-pion spectrum computed using lattice QCD from six ensembles\non lattices elongated in one of the spatial dimensions. A two-flavor dynamical\nlattice QCD action is used with two quark masses corresponding to a pion mass\nof 315 MeV and 224 MeV. The spectrum in the elastic region is subjected to a\nglobal fit which takes into account full correlations across isospin, pion mass\nand decay constant. The parameters from the fit are used to perform a chiral\nextrapolation to the physical point. The cross-channel fit results in a more\nprecise determination of the parameters of the model when compared with single\nchannel fits. We obtain $m_\\pi a_0^{I=0}=0.2132(9)$, and $m_\\pi\na_0^{I=2}=0.0433(2)$ as well as $m_\\sigma=443(3)-i221(6)$ MeV and\n$m_\\rho=724(4)-i67(1)$ MeV. Several aspects of scale setting and consistency\nwith previous analyses of lattice QCD results are discussed as well.",
        "positive": "Abelian chiral gauge theories on the lattice with exact gauge invariance: It is shown that U(1) chiral gauge theories with anomaly-free multiplets of\nWeyl fermions can be put on the lattice without breaking the gauge invariance\nor violating any other fundamental principle. The Ginsparg-Wilson relation\nplays a key role in this construction, which is non-perturbative and includes\nall topological sectors of the theory in finite volume. In particular, the\ncancellation of the gauge anomaly and the absence of global topological\nobstructions can be established on the basis of this relation and the lattice\nsymmetries alone."
    },
    {
        "anchor": "Rough Interfaces Beyond the Gaussian Approximation: We compare predictions of the Capillary Wave Model beyond its Gaussian\napproximation with Monte Carlo results for the energy gap and the surface\nenergy of the 3D Ising model in the scaling region. Our study reveals that the\nfinite size effects of these quantities are well described by the Capillary\nWave Model, expanded to two--loop order ( one order beyond the Gaussian\napproximation).",
        "positive": "Stable solvers for real-time Complex Langevin: This study explores the potential of modern implicit solvers for stochastic\npartial differential equations in the simulation of real-time complex Langevin\ndynamics. Not only do these methods offer asymptotic stability, rendering the\nissue of runaway solution moot, but they also allow us to simulate at\ncomparatively largeLangevin time steps, leading to lower computational cost. We\ncompare different ways of regularizing the underlying path integral and\nestimate the errors introduced due to the finite Langevin time. Based on that\ninsight, we implement benchmark (non-)thermal simulations of the quantum\nanharmonic oscillator on the canonical Schwinger-Keldysh contour of short\nreal-time extent."
    },
    {
        "anchor": "Irreducible Multiplets of Three-Quark Operators on the Lattice:\n  Controlling Mixing under Renormalization: High luminosity accelerators have greatly increased the interest in\nsemi-exclusive and exclusive reactions involving nucleons. The relevant\ntheoretical information is contained in the nucleon wavefunction and can be\nparametrized by moments of the nucleon distribution amplitudes, which in turn\nare linked to matrix elements of three-quark operators. These can be calculated\nfrom first principles in lattice QCD. However, on the lattice the problems of\noperator mixing under renormalization are rather involved. In a systematic\napproach we investigate this issue in depth. Using the spinorial symmetry group\nof the hypercubic lattice we derive irreducibly transforming three-quark\noperators, which allow us to control the mixing pattern.",
        "positive": "The rooting issue for a lattice fermion formulation similar to staggered\n  fermions but without taste mixing: To investigate the viability of the 4th root trick for the staggered fermion\ndeterminant in a simpler setting, we consider a two taste (flavor) lattice\nfermion formulation with no taste mixing but with exact taste-nonsinglet chiral\nsymmetries analogous to the taste-nonsinglet $U(1)_A$ symmetry of staggered\nfermions. M. Creutz's objections to the rooting trick apply just as much in\nthis setting. To counter them we show that the formulation has robust would-be\nzero-modes in topologically nontrivial gauge backgrounds, and that these\nmanifest themselves in a viable way in the rooted fermion determinant and also\nin the disconnected piece of the pseudoscalar meson propagator as required to\nsolve the U(1) problem. Also, our rooted theory is heuristically seen to be in\nthe right universality class for QCD if the same is true for an unrooted mixed\nfermion action theory."
    },
    {
        "anchor": "Testing a non-perturbative mechanism for elementary fermion mass\n  generation: numerical results: Based on a recent proposal according to which elementary particle masses\ncould be generated by a non-perturbative dynamical phenomenon, alternative to\nthe Higgs mechanism, we carry out lattice simulations of a model where a\nnon-abelian strongly interacting fermion doublet is also coupled to a doublet\nof complex scalar fields via a Yukawa and an \"irrelevant\" Wilson-like term. In\nthis pioneering study we use naive fermions and work in the quenched\napproximation. We present preliminary numerical results both in the Wigner and\nin the Nambu-Goldstone phase, focusing on the observables relevant to check the\noccurrence of the conjectured dynamical fermion mass generation effect in the\ncontinuum limit of the critical theory in its spontaneously broken phase.",
        "positive": "High Temperature 3D QCD: Dimensional Reduction at Work: We investigate the three-dimensional SU(3) gauge theory at finite temperature\nin the framework of dimensional reduction. The large scale properties of this\ntheory are expected to be conceptually more complicated than in four\ndimensions. The dimensionally reduced action is computed in closed analytical\nform. The resulting effective two-dimensional theory is studied numerically\nboth in the electric and magnetic sector. We find that dimensional reduction\nworks excellently down to temperatures of 1.5 times the deconfinement phase\ntransition temperature and even on rather short length scales. We obtain strong\nevidence that for ${\\rm QCD}_3$, even at high temperature the colour averaged\npotential is represented by the exchange of a single state, at variance with\nthe usual Debye screening picture involving a pair of electric gluons."
    },
    {
        "anchor": "Systematic Expansion for Full QCD Based on the Valence Approximation: We construct a systematic expansion for full QCD. The leading term gives the\nvalence (quenched) approximation.",
        "positive": "Topology by improved cooling: susceptibility and size distributions: We use a cooling algorithm based on an improved action with scale invariant\ninstanton solutions, which needs no monitoring or calibration and has a\ninherent cut off for dislocations. We present results for SU(2) Yang-Mills\ntheory where the method provides good susceptibility data and physical size\ndistributions of instantons."
    },
    {
        "anchor": "Spatially improved operators for excited hadrons on the lattice: We present a new approach for determining spatially optimized operators that\ncan be used for lattice spectroscopy of excited hadrons. Jacobi smeared quark\nsources with different widths are combined to construct hadron operators with\ndifferent spatial wave functions. We use the variational method to determine\nthose linear combinations of operators that have optimal overlap with ground\nand excited states. The details of the new approach are discussed and we\ndemonstrate the power of the method using examples from quenched baryon and\nmeson spectroscopy. In particular we study the Roper state and rho(1450) and\ndiscuss some physical implications of our tests.",
        "positive": "Some Applications of the Overlap Formalism: The massless vector Schwinger model with $N_f=1,2,3,4$ number of flavors is\nstudied on the lattice using the overlap formalism. A full Monte Carlo\nsimulation yields values for the bilinear fermion condensate that are in\nagreement with the exact solution of the continuum Schwinger model with an\nadded Thirring interaction."
    },
    {
        "anchor": "Interactive Visualization Package for 4D Lattice Field Theories: Recent interest in exploring local vacuum structure of QCD through the\nproperties of the eigenmodes of the lattice Dirac operators rises again the\nchallenge to visualize four-dimensional objects and structures which appear in\nlattice field theories. In spite of complex and powerful commercial\nvisualization software packages on the market, there are reasons to develop\nInteractive Visualization Package (IVP). We believe that an apprehension of the\ncomplex structures is possible only through the interactive approach, with the\nuser being able to manipulate data representations and slices through the\nlattice in real-time. Further insight should also be gained by an interactive\nparallel examination of different physical quantities, e.g. eigenmode density\nwith topological charge or action densities. Finally, thanks to constantly\nfalling hardware prices, IVP makes it possible to use almost any Linux PC as a\nvisualization tool for research in lattice field theory.",
        "positive": "Topology and Staggered Fermion Action Improvement: It is conventional wisdom that staggered fermions do not feel gauge field\ntopology. However, the response of staggered fermion eigenmodes to the topology\nof the gauge field can depend quite sensitively on the way in which the\nstaggered fermion action is improved. We study this issue using a variety of\nimproved staggered quark actions. We observe that the separation between the\n``would be'' zero modes and the non-chiral modes increases with the level of\nimprovement. This enables the ``zero modes'' to be identified unambiguously.\nThe distribution of the remaining non-chiral modes is compared with the\npredictions of Random Matrix Theory. Satisfactory agreement is obtained."
    },
    {
        "anchor": "Chiral symmetry and taste symmetry from the eigenvalue spectrum of\n  staggered Dirac operators: We investigate general properties of the eigenvalue spectrum for improved\nstaggered quarks. We introduce a new chirality operator $[\\gamma_5 \\otimes 1]$\nand a new shift operator $[1 \\otimes \\xi_5]$, which respect the same recursion\nrelation as the $\\gamma_5$ operator in the continuum. Then we show that matrix\nelements of the chirality operator sandwiched between two eigenstates of the\nstaggered Dirac operator are related to those of the shift operator by the Ward\nidentity of the conserved $U(1)_A$ symmetry of staggered fermion actions. We\nperform a numerical study in quenched QCD using HYP staggered quarks to\ndemonstrate the Ward identity. We introduce a new concept of leakage patterns\nwhich collectively represent the matrix elements of the chirality operator and\nthe shift operator sandwiched between two eigenstates of the staggered Dirac\noperator. The leakage pattern provides a new method to identify zero modes and\nnon-zero modes in the Dirac eigenvalue spectrum. This method is as robust as\nthe spectral flow method but requires much less computing power. Analysis using\na machine learning technique confirms that the leakage pattern is universal,\nsince the staggered Dirac eigenmodes on normal gauge configurations respect it.\nIn addition, the leakage pattern can be used to determine a ratio of\nrenormalization factors as a by-product. We conclude that it might be possible\nand realistic to measure the topological charge $Q$ using the Atiya-Singer\nindex theorem and the leakage pattern of the chirality operator in the\nstaggered fermion formalism.",
        "positive": "Transport and spectral functions in high-temperature QCD: The current status of transport coefficients in relativistic field theories\nat high temperature is reviewed. I contrast weak coupling results obtained\nusing kinetic theory/diagrammatic techniques with strong coupling results\nobtained using gauge/gravity duality, and describe the recent developments in\nextracting transport coefficients and spectral functions from lattice QCD\nsimulations. The fate of quarkonium at high temperature as seen from the\nlattice is briefly mentioned as well."
    },
    {
        "anchor": "Lattice gauge symmetry in neural networks: We review a novel neural network architecture called lattice gauge\nequivariant convolutional neural networks (L-CNNs), which can be applied to\ngeneric machine learning problems in lattice gauge theory while exactly\npreserving gauge symmetry. We discuss the concept of gauge equivariance which\nwe use to explicitly construct a gauge equivariant convolutional layer and a\nbilinear layer. The performance of L-CNNs and non-equivariant CNNs is compared\nusing seemingly simple non-linear regression tasks, where L-CNNs demonstrate\ngeneralizability and achieve a high degree of accuracy in their predictions\ncompared to their non-equivariant counterparts.",
        "positive": "Interface tension in SU(3) lattice gauge theory at finite temperatures\n  on an $N_t=2$ lattice: The surface tension $\\sigma$ of the confined-deconfined interface is\ncalculated in pure $SU(3)$ lattice gauge theory at finite temperatures\nemploying the operator and integral methods on a lattice of a size $8^2\\times\nN_z\\times 2$ with $N_z=16$ and 40. Analyses of non-perturbative corrections in\nasymmetry response functions strongly indicate that the use of one-loop values\nfor the response functions lead to an overestimate of $\\sigma$ in the operator\nmethod. The operator method also suffers more from finite-size effects due to a\nfinite thickness of the interface, leading us to conclude that the integral\nmethod yields more reliable values for $\\sigma$. Our result with the integral\nmethod $\\sigma/T_c^3=0.134(16)$ is consistent with earlier results and also\nwith that obtained with a transfer matrix method. Result is also reported on\n$\\sigma$ obtained on a lattice $18^2\\times 48\\times 4$ with the integral\nmethod."
    },
    {
        "anchor": "Semi-Analytical Solution of the $\u03c6^4$ Theory on an $F_4$ Lattice: Investigating the cutoff dependence of the Higgs mass triviality bound, the\n$\\phi^4$ theory is formulated on an $F_4$ lattice which preserves Lorentz\ninvariance to a higher degree than the commonly used hypercubic lattice. I\nsolve this model non-perturbatively by evaluating the high temperature\nexpansion through 13th order following the approach of L\\\"uscher and Weisz. The\nresults are continued across the transition line into the broken phase by\nintegrating the perturbative RG equations. In the broken phase, the\nrenormalized coupling never exceeds 2/3 of the tree level unitarity bound when\n$\\Lambda/m_R \\geq 2$. The results confirm recent Monte Carlo data and I obtain\nas an upper bound for the Higgs mass $m_R/f_\\pi \\leq 2.46 \\pm 0.02_{\\rm HTE}\n\\pm 0.08_{\\rm PT}$ at $\\Lambda/m_R=2$.",
        "positive": "Results for $\u03b1_s$ from the decoupling strategy: We present analysis details and new results for the strong coupling\n$\\alpha_s(m_Z)$, determined by the decoupling strategy. We measure a massive\ngradient flow (GF) coupling defined in finite volume with Schr\\\"odinger\nfunctional (SF) boundary conditions in a theory with $N_\\text{f}=3$ degenerate\nheavy quarks of mass $M$. The massive couplings are matched to effective\ncouplings in pure gauge. Using the running in the pure gauge theory and the\nperturbative relation of the Lambda parameters, the Lambda parameter of the\nthree flavor theory is obtained by an extrapolation to infinite M. Our final\nresult is compatible both with the FLAG average and with the previous ALPHA\nresult, albeit with a slightly smaller, yet still statistics dominated, error.\nThis constitutes a non-trivial check, as the decoupling strategy is\nconceptually very different from the 3-flavor QCD step-scaling method, and so\nare most of its systematic errors. These include the uncertainties of the\ndecoupling and continuum limits, which we discuss in some detail. Furthermore,\nby relying on decoupling once again, we could estimate the small $O(a)$ and\n$O(1/M)$ contaminations to the massive GF coupling stemming from the SF\nboundaries by means of pure gauge simulations."
    },
    {
        "anchor": "Master-field simulations of QCD: We report on the first master-field simulations of QCD with 2+1 dynamical\nquark flavours using non-perturbatively improved stabilised Wilson fermions.\nOur simulations are performed at a lattice spacing of 0.094 fm with 96 and 192\npoints in each direction. On both lattices, the pion and kaon masses are equal\nto 270 and 450 MeV, respectively, and $m_\\pi L$ thus reaches an unprecedented\nvalue of 25 on the larger lattice. This setup matches a single point on a\nchiral trajectory with fixed trace of the quark mass matrix and allows for\ncomparisons to standard large-scale simulations. We present our algorithmic\nsetup and performance measures, and report about our experience in thermalising\nlarge master-field lattices with fermions.",
        "positive": "Calculation of $K\\to\u03c0\u03c0$ decay amplitudes from $K\\to\u03c0$ matrix\n  elements in quenched domain-wall QCD: We present a calculation of the $K\\to\\pi\\pi$ decay amplitudes from the\n$K\\to\\pi$ matrix elements using leading order relations derived in chiral\nperturbation theory. Numerical simulations are carried out in quenched QCD with\nthe domain-wall fermion action and the renormalization group improved gluon\naction. Our results show that the I=2 amplitude is reasonably consistent with\nexperiment whereas the I=0 amplitude is sizably smaller. Consequently the\n$\\Delta I=1/2$ enhancement is only half of the experimental value, and\n$\\epsilon'/\\epsilon$ is negative."
    },
    {
        "anchor": "Center group dominance in quark confinement: We show that the color $N$ dependent area law falloffs of the double-winding\nWilson loop averages for the $SU(N)$ lattice gauge theory obtained in the\npreceding works are reproduced from the corresponding lattice Abelian gauge\ntheory with the center gauge group $Z_N$. This result indicates the center\ngroup dominance in quark confinement.",
        "positive": "Numerical evidence of chiral magnetic effect in lattice gauge theory: The chiral magnetic effect is the generation of electric current of quarks\nalong external magnetic field in the background of topologically nontrivial\ngluon fields. There is a recent evidence that this effect is observed by the\nSTAR Collaboration in heavy ion collisions at RHIC. In our paper we study\nqualitative signatures of the chiral magnetic effect using quenched lattice\nsimulations. We find indications that the electric current is indeed enhanced\nin the direction of the magnetic field both in equilibrium configurations of\nthe quantum gluon fields and in a smooth gluon background with nonzero\ntopological charge. In the confinement phase the magnetic field enhances the\nlocal fluctuations of both the electric charge and chiral charge densities. In\nthe deconfinement phase the effects of the magnetic field become smaller,\npossibly due to thermal screening. Using a simple model of a fireball we obtain\na good agreement between our data and experimental results of the STAR\nCollaboration."
    },
    {
        "anchor": "Fast Fermion Smearing Scheme with Gaussian-like Profile: We propose a novel smearing scheme which gives a Gaussian-like profile and is\nmore efficient than the traditional Gaussian smearing in terms of computer time\nconsumption. We also carry out a detailed analysis of the profiles, smearing\nsizes, and the behaviors of hadron effective masses of different smearing\nschemes, and point out that having a sufficient number of gauge paths in a\nsmearing scheme is essential to produce strong smearing effects. For a moderate\nsmearing size $\\bar{r}\\sim 10a$, the time cost for the novel smearing is less\nthan $1/8$ of that for the traditional Gaussian smearing. In practical lattice\ncalculations with larger smearing sizes or finer lattice spacings the\nimprovement will be more substantial.",
        "positive": "Baryon masses, chiral extrapolations, and all that: We calculate the baryon octet masses to fourth order in chiral perturbation\ntheory employing dimensional and cut-off regularization. We analyze the pion\nand kaon mass dependences of the baryon masses based on the MILC data. We show\nthat chiral perturbation theory gives stable chiral extrapolation functions for\npion (kaon) masses below 550 (600) MeV. The pion-nucleon sigma term in SU(3) is\nalso investigated, we find \\sigma_{\\pi N} (0) = 50.7 - 53.7 MeV."
    },
    {
        "anchor": "Review on Quantum Computing for Lattice Field Theory: In these proceedings, we review recent advances in applying quantum computing\nto lattice field theory. Quantum computing offers the prospect to simulate\nlattice field theories in parameter regimes that are largely inaccessible with\nthe conventional Monte Carlo approach, such as the sign-problem afflicted\nregimes of finite baryon density, topological terms, and out-of-equilibrium\ndynamics. First proof-of-concept quantum computations of lattice gauge theories\nin (1+1) dimensions have been accomplished, and first resource-efficient\nquantum algorithms for lattice gauge theories in (1+1) and (2+1) dimensions\nhave been developed. The path towards quantum computations of (3+1)-dimensional\nlattice gauge theories, including Lattice QCD, requires many incremental steps\nof improving both quantum hardware and quantum algorithms. After reviewing\nthese requirements and recent advances, we discuss the main challenges and\nfuture directions.",
        "positive": "Application of the path optimization method to a discrete spin system: The path optimization method, which is proposed to control the sign problem\nin quantum field theories with continuous degrees of freedom by machine\nlearning, is applied to a spin model with discrete degrees of freedom. The path\noptimization method is applied by replacing the spins with dynamical variables\nvia the Hubbard-Stratonovich transformation, and the sum with the integral. The\none-dimensional (Lenz-)Ising model with a complex coupling constant is used as\na laboratory for the sign problem in the spin model. The average phase factor\nis enhanced by the path optimization method, indicating that the method can\nweaken the sign problem. Our result reproduces the analytic values with\ncontrolled statistical errors."
    },
    {
        "anchor": "The QCD equation of state from the lattice: The equation of state of QCD at finite temperatures and baryon densities has\na wide range of applications in many fields of modern particle and nuclear\nphysics. It is the main ingredient to describe the dynamics of experimental\nheavy ion collisions, the expansion of the early universe in the standard model\nera and the interior of compact stars. On most scales of interest, QCD is\nstrongly coupled and not amenable to perturbative investigations. Over the last\ndecade, first principles calculations using lattice QCD have reached maturity,\nin the sense that for particular discretisation schemes simulations at the\nphysical point have become possible, finite temperature results near the\ncontinuum limit are available and systematic errors begin to be controlled.\nThis review summarises the current theoretical and numerical state of the art\nbased on staggered and Wilson fermions.",
        "positive": "The disorder parameter of dual superconductivity in QCD revisited: We discover the origin of the pathologies of the disorder parameter used in\nprevious papers to detect dual superconductivity of QCD vacuum, and we remove\nthem by defining an improved disorder parameter. A check of the approach is\nmade by numerical simulations of SU(2) gauge theory, which demonstrate that the\napproach is consistent and with it that deconfinement is a transition from dual\nsuperconductor to normal."
    },
    {
        "anchor": "The deconfining phase transition of SO(N) gauge theories in 2+1\n  dimensions: We calculate the deconfining temperature of SO(N) gauge theories in 2+1\ndimensions, and determine the order of the phase transition as a function of N,\nfor various values of N in the range [4,16]. We do so by extrapolating our\nlattice results to the infinite volume limit, and then to the continuum limit,\nfor each value of N. We then extrapolate to the N=infinity limit and observe\nthat the SO(N) and SU(N) deconfining temperatures agree in that limit. We find\nthat the the deconfining temperatures of all the SO(N) gauge theories appear to\nfollow a single smooth function of N, despite the lack of a non-trivial centre\nfor odd N. We also compare the deconfining temperatures of SO(6) with SU(4),\nand of SO(4) with SU(2)xSU(2), motivated by the fact that these pairs of gauge\ntheories share the same Lie algebras.",
        "positive": "Report of the Snowmass 2021 Topical Group on Lattice Gauge Theory: Lattice gauge theory continues to be a powerful theoretical and computational\napproach to simulating strongly interacting quantum field theories, whose\napplications permeate almost all disciplines of modern-day research in\nHigh-Energy Physics. Whether it is to enable precision quark- and lepton-flavor\nphysics, to uncover signals of new physics in nucleons and nuclei, to elucidate\nhadron structure and spectrum, to serve as a numerical laboratory to reach\nbeyond the Standard Model, or to invent and improve state-of-the-art\ncomputational paradigms, the lattice-gauge-theory program is in a prime\nposition to impact the course of developments and enhance discovery potential\nof a vibrant experimental program in High-Energy Physics over the coming\ndecade. This projection is based on abundant successful results that have\nemerged using lattice gauge theory over the years: on continued improvement in\ntheoretical frameworks and algorithmic suits; on the forthcoming transition\ninto the exascale era of high-performance computing; and on a skillful,\ndedicated, and organized community of lattice gauge theorists in the U.S. and\nworldwide. The prospects of this effort in pushing the frontiers of research in\nHigh-Energy Physics have recently been studied within the U.S. decadal Particle\nPhysics Planning Exercise (Snowmass 2021), and the conclusions are summarized\nin this Topical Report."
    },
    {
        "anchor": "Potential description of charmonium and charmed-strange mesons from\n  lattice QCD: We present spin-independent and spin-spin interquark potentials for the\ncharmonium and charmed-strange mesons, which are calculated in 2+1 flavor\nlattice QCD simulations using the PACS-CS gauge configurations generated at the\nlightest pion mass ($M_\\pi \\approx 156(7)$~MeV) with a lattice cutoff of\n$a^{-1}\\approx 2.2$ GeV and a spatial volume of $(3~{\\rm fm})^3$. For the charm\nquark, we use a relativistic heavy quark (RHQ) action with fine tuned RHQ\nparameters, which closely reproduce both the experimental spin-averaged mass\nand hyper-fine splitting of the $1S$ charmonium. The interquark potential and\nthe quark kinetic mass, both of which are key ingredients within the potential\ndescription of heavy-heavy and heavy-light mesons, are determined from the\nequal-time Bethe-Salpeter (BS) amplitude. The charmonium potentials are\nobtained from the BS wave function of $1S$ charmonia ($\\eta_c$ and $J/\\psi$\nmesons), while the charmed-strange potential are calculated from the $D_s$ and\n$D_s^{\\ast}$ heavy-light mesons. We then use resulting potentials and quark\nmasses as purely theoretical inputs so as to solve the nonrelativistic\nSchr\\\"odinger equation for calculating accessible energy levels of charmonium\nand charmed-strange mesons without unknown parameters. The resultant spectra\nbelow the $D\\bar{D}$ and $DK$ thresholds excellently agree with\nwell-established experimental data.",
        "positive": "Gauge-Invariant Smearing and Matrix Correlators using Wilson Fermions at\n  beta=6.2: We present an investigation of gauge-invariant smearing for Wilson fermions\nin quenched lattice QCD on a $24^3 \\times 48$ lattice at $\\beta = 6.2$. We\ndemonstrate a smearing algorithm that allows a substantial improvement in the\ndetermination of the baryon spectrum obtained using propagators smeared at both\nsource and sink, at only a small computational cost. We investigate the matrix\nof correlators constructed from local and smeared operators, and are able to\nexpose excited states of both the mesons and baryons."
    },
    {
        "anchor": "QCD viscosity by combining the gradient flow and sparse modeling methods: We give a new description to obtain the shear viscosity in QCD at finite\ntemperature. Firstly, we obtain the correlation function of the renormalized\nenergy-momentum tensor using the gradient flow method. Secondly, we estimate\nthe spectral function from the smeared correlation functions using the sparse\nmodeling method. The combination of these two methods looks promising to\ndetermine the shear viscosity precisely.",
        "positive": "Lattice QCD on Small Computers: We demonstrate that lattice QCD calculations can be made $10^3$--$10^6$ times\nfaster by using very coarse lattices. To obtain accurate results, we replace\nthe standard lattice actions by perturbatively-improved actions with\ntadpole-improved correction terms that remove the leading errors due to the\nlattice. To illustrate the power of this approach, we calculate the\nstatic-quark potential, and the charmonium spectrum and wavefunctions using a\ndesktop computer. We obtain accurate results that are independent of the\nlattice spacing and agree well with experiment."
    },
    {
        "anchor": "SU(3) Lattice Gauge Theory With Adjoint Action At Nonzero Temperature: We study the thermal phase diagram of pure SU(3) gauge theory with\nfundamental and adjoint couplings. We improve previous estimates of the\nposition of the bulk transition line and determine the thermal deconfinement\ntransition lines for $N_t=2,4,6,$ and 8. For $N_t > 4$ the deconfinement\ntransition line splits cleanly away from the bulk transition line. With\nincreasing $N_t$ the thermal deconfinement transition lines shift to\nincreasingly weaker coupling, joining onto the bulk transition line at\nincreasingly larger $\\beta_a$ in a pattern consistent with the usual\nuniversality picture of lattice gauge theories.",
        "positive": "Ratio of kaon and pion leptonic decay constants with $N_f = 2 + 1 + 1$\n  Wilson-clover twisted-mass fermions: We present a determination of the ratio of kaon and pion leptonic decay\nconstants in isosymmetric QCD (isoQCD), $f_K / f_\\pi$, making use of the gauge\nensembles produced by the Extended Twisted Mass Collaboration (ETMC) with $N_f\n= 2 + 1 + 1$ flavors of Wilson-clover twisted-mass quarks, including\nconfigurations close to the physical point for all dynamical flavors. The\nsimulations are carried out at three values of the lattice spacing ranging from\n$\\sim 0.068$ to $\\sim 0.092$ fm with linear lattice size up to $L \\sim 5.5$~fm.\nThe scale is set by the PDG value of the pion decay constant, $f_\\pi^{isoQCD} =\n130.4~(2)$ MeV, at the isoQCD pion point, $M_\\pi^{isoQCD} = 135.0~(2)$ MeV,\nobtaining for the gradient-flow (GF) scales the values $w_0 = 0.17383~(63)$ fm,\n$\\sqrt{t_0} = 0.14436~(61)$ fm and $t_0 / w_0 = 0.11969~(62)$ fm. The data are\nanalyzed within the framework of SU(2) Chiral Perturbation Theory (ChPT)\nwithout resorting to the use of renormalized quark masses. At the isoQCD kaon\npoint $M_K^{isoQCD} = 494.2~(4)$ MeV we get $(f_K / f_\\pi)^{isoQCD} =\n1.1995~(44)$, where the error includes both statistical and systematic\nuncertainties. Implications for the Cabibbo-Kobayashi-Maskawa (CKM) matrix\nelement $|V_{us}|$ and for the first-row CKM unitarity are discussed."
    },
    {
        "anchor": "A nested Krylov subspace method for the overlap operator: We present a novel method to compute the overlap Dirac operator at zero and\nnonzero quark chemical potential. To approximate the sign function of large,\nsparse matrices, standard methods project the operator on a much smaller Krylov\nsubspace, on which the matrix function is computed exactly. However, for large\nlattices this subspace can still be too large for an efficient calculation of\nthe sign function. The idea of the new method is to nest Krylov subspace\napproximations by making a further projection on an even smaller subspace,\nwhich is then small enough to compute the sign function efficiently, and this\nwithout any noticeable loss of numerical accuracy. We demonstrate the\nefficiency of the method both on Hermitian and non-Hermitian matrices.",
        "positive": "Two-Flavor Lattice QCD with a Finite Density of Heavy Quarks:\n  Heavy-Dense Limit and \"Particle-Hole\" Symmetry: We investigate the properties of the half-filling point in lattice QCD\n(LQCD), in particular the disappearance of the sign problem and the emergence\nof an apparent particle-hole symmetry, and try to understand where these\nproperties come from by studying the heavy-dense fermion determinant and the\ncorresponding strong-coupling partition function (which can be integrated\nanalytically). We then add in a first step an effective Polyakov loop gauge\naction (which reproduces the leading terms in the character expansion of the\nWilson gauge action) to the heavy-dense partition function and try to analyze\nhow some of the properties of the half-filling point change when leaving the\nstrong coupling limit. In a second step, we take also the leading\nnearest-neighbor fermion hopping terms into account (including gauge\ninteractions in the fundamental representation) and mention how the method\ncould be improved further to incorporate the full set of nearest-neighbor\nfermion hoppings. Using our mean-field method, we also obtain an approximate\n($\\mu$,T) phase diagram for heavy-dense LQCD at finite inverse gauge coupling\n$\\beta$. Finally, we propose a simple criterion to identify the chemical\npotential beyond which lattice artifacts become dominant."
    },
    {
        "anchor": "Two-colour Lattice QCD with dynamical fermions at non-zero density\n  versus Matrix Models: We provide first evidence that Matrix Models describe the low lying complex\nDirac eigenvalues in a theory with dynamical fermions at non-zero density.\nLattice data for gauge group SU(2) with staggered fermions are compared to\ndetailed analytical results from Matrix Models in the corresponding symmetry\nclass, the complex chiral Symplectic Ensemble. They confirm the predicted\ndependence on chemical potential, quark mass and volume.",
        "positive": "Anderson Localization in Quark-Gluon Plasma: At low temperature the low end of the QCD Dirac spectrum is well described by\nchiral random matrix theory. In contrast, at high temperature there is no\nsimilar statistical description of the spectrum. We show that at high\ntemperature the lowest part of the spectrum consists of a band of statistically\nuncorrelated eigenvalues obeying essentially Poisson statistics and the\ncorresponding eigenvectors are extremely localized. Going up in the spectrum\nthe spectral density rapidly increases and the eigenvectors become more and\nmore delocalized. At the same time the spectral statistics gradually crosses\nover to the bulk statistics expected from the corresponding random matrix\nensemble. This phenomenon is reminiscent of Anderson localization in disordered\nconductors. Our findings are based on staggered Dirac spectra in quenched SU(2)\nlattice simulations."
    },
    {
        "anchor": "Future applications of the Yang-Mills gradient flow in lattice QCD: The Yang--Mills gradient flow has many interesting applications in lattice\nQCD. In this talk, some recent and possible future uses of the flow are\ndiscussed, emphasizing the underlying theoretical concepts rather than any\ncomputational aspects.",
        "positive": "Dual of 3-dimensional pure SU(2) Lattice Gauge Theory and the\n  Ponzano-Regge Model: By carrying out character expansion and integration over all link variables,\nthe partition function of 3-dimensional pure SU(2) lattice gauge theory is\nrewritten in terms of 6j symbols. The result is Ponzano-Regge model of\n3-dimensional gravity with a term that explicitly breaks general coordinate\ninvariance. Conversely, we show that dual of Ponzano-Regge model is an SU(2)\nlattice gauge theory where all plaquette variables are constrained to the\nidentity matrix and therefore the model needs no further regularization. Our\ntechniques are applicable to other models with non-abelian symmetries in any\ndimension and provide duality transform for the partition function."
    },
    {
        "anchor": "New extended high temperature series for the N-vector spin models on\n  three-dimensional bipartite lattices: High temperature expansions for the susceptibility and the second correlation\nmoment of the classical N-vector model (O(N) symmetric Heisenberg model) on the\nsc and the bcc lattices are extended to order $\\beta^{19}$ for arbitrary N. For\nN= 2,3,4.. we present revised estimates of the critical parameters from the\nnewly computed coefficients.",
        "positive": "Monopoles and vortices in pure gauge theories and in Higgs theories: Smeared Abelian and center gauges are introduced in pure non-Abelian lattice\ngauge theories. Popular Abelian and center gauges are limits of smeared gauges.\nSmeared gauges are also shown to be equivalent to Higgs theories. As a result,\ndistributions and interactions of monopoles and vortices, which are objects\nresponsible for confinement in pure gauge theories, can be studied by\ninvestigating classical solutions of Higgs theories."
    },
    {
        "anchor": "Self-Avoiding Gonihedric Srting and Spin Systems: We classify different theories of self-intersecting random surfaces assigning\nspecial weights to intersections. When self-intersection coupling constant\n$\\kappa$ tends to zero, then the surface can freely inetrsect and it is\ncompletely self-avoiding when $\\kappa$ tends to infinity. Equivalent spin\nsystems for this general case were constructed. In two-dimension the system\nwith $\\kappa = 0$ is in complete disorder as it is in the case of 2D gauge\nIsing system.",
        "positive": "Scaling Behavior in 4D Simplicial Quantum Gravity: Scaling relations in four-dimensional simplicial quantum gravity are proposed\nusing the concept of the geodesic distance. Based on the analogy of a loop\nlength distribution in the two-dimensional case, the scaling relations of the\nboundary volume distribution in four dimensions are discussed in three regions:\nthe strong-coupling phase, the critical point and the weak-coupling phase. In\neach phase a different scaling behavior is found."
    },
    {
        "anchor": "Excited nucleon spectrum using a non-perturbatively improved clover\n  fermion action: We discuss the extraction of negative-parity baryon masses from lattice QCD\ncalculations. The mass of the lowest-lying negative-parity $J = 1/2^{-}$ state\nis computed in quenched lattice QCD using an ${\\cal O}(a)$-improved clover\nfermion action, and a splitting found with the nucleon mass. The calculation is\nperformed on two lattice volumes, and three lattice spacings enabling a study\nof both finite-volume and finite-lattice-spacing uncertainties. A measurement\nof the first excited radial excitation of the nucleon finds a mass considerably\nlarger than that of the negative-parity ground state, in accord with other\nlattice determinations but in disagreement with experiment. Results are also\npresented for the lightest negative-parity $I=3/2$ state.",
        "positive": "Estimation of Thermodynamic Observables in Lattice Field Theories with\n  Deep Generative Models: In this work, we demonstrate that applying deep generative machine learning\nmodels for lattice field theory is a promising route for solving problems where\nMarkov Chain Monte Carlo (MCMC) methods are problematic. More specifically, we\nshow that generative models can be used to estimate the absolute value of the\nfree energy, which is in contrast to existing MCMC-based methods which are\nlimited to only estimate free energy differences. We demonstrate the\neffectiveness of the proposed method for two-dimensional $\\phi^4$ theory and\ncompare it to MCMC-based methods in detailed numerical experiments."
    },
    {
        "anchor": "Recursive sampling simulations of 3D gravity coupled to scalar fermions: We study numerically the phase structure of a model of 3D gravity interacting\nwith scalar fermions. We measure the 3D counterpart of the \"string\"\nsusceptibility exponent as a function of the inverse Newton coupling $\\alpha$.\nWe show that there are two phases separated by a critical point around\n$\\alpha_c \\simeq 2$. The numerical results support the hypothesis that the\nphase structures of 3D and 2D simplicial gravity are qualitatively similar, the\ninverse Newton coupling in 3D playing the role of the central charge of matter\nin 2D.",
        "positive": "Three and Two Colours Finite Density QCD at Strong Coupling: A New Look: Simulations in finite density, beta=0 lattice QCD by means of the\nMonomer-Dimer-Polymer algorithm show a signal of first order transition at\nfinite temporal size. This behaviour agrees with predictions of the mean field\napproximation, but is difficult to reconcile with infinite mass analytical\nsolution. The MDP simulations are considered in detail and severe convergence\nproblems are found for the SU(3) gauge group, in a wide region of chemical\npotential. Simulations of SU(2) model show discrepancies with MDP results as\nwell."
    },
    {
        "anchor": "Index of a family of lattice Dirac operators and its relation to the\n  non-abelian anomaly on the lattice: In the continuum, a topological obstruction to the vanishing of the\nnon-abelian anomaly in 2n dimensions is given by the index of a certain Dirac\noperator in 2n+2 dimensions, or equivalently, the index of a 2-parameter family\nof Dirac operators in 2n dimensions. In this paper an analogous result is\nderived for chiral fermions on the lattice in the Overlap formulation. This\ninvolves deriving an Index Theorem for a family of lattice Dirac operators\nsatisfying the Ginsparg--Wilson relation. The index density is proportional to\nLuescher's topological field in 2n+2 dimensions.",
        "positive": "Constraints on the IR behavior of the gluon propagator in Yang-Mills\n  theories: We present rigorous upper and lower bounds for the zero-momentum gluon\npropagator D(0) of Yang-Mills theories in terms of the average value of the\ngluon field. This allows us to perform a controlled extrapolation of lattice\ndata to infinite volume, showing that the infrared limit of the Landau-gauge\ngluon propagator in SU(2) gauge theory is finite and nonzero in three and in\nfour space-time dimensions. In the two-dimensional case we find D(0) = 0, in\nagreement with Ref. [1]. We suggest an explanation for these results. We note\nthat our discussion is general, although we only apply our analysis to pure\ngauge theory in Landau gauge. Simulations have been performed on the IBM\nsupercomputer at the University of Sao Paulo."
    },
    {
        "anchor": "The monopole mass in the three-dimensional Georgi-Glashow model: We study the three-dimensional Georgi-Glashow model to demonstrate how\nmagnetic monopoles can be studied fully non-perturbatively in lattice Monte\nCarlo simulations, without any assumptions about the smoothness of the field\nconfigurations. We examine the apparent contradiction between the conjectured\nanalytic connection of the `broken' and `symmetric' phases, and the\ninterpretation of the mass (i.e., the free energy) of the fully quantised 't\nHooft-Polyakov monopole as an order parameter to distinguish the phases. We use\nMonte Carlo simulations to measure the monopole free energy and its first\nderivative with respect to the scalar mass. On small volumes we compare this to\nsemi-classical predictions for the monopole. On large volumes we show that the\nfree energy is screened to zero, signalling the formation of a confining\nmonopole condensate. This screening does not allow the monopole mass to be\ninterpreted as an order parameter, resolving the paradox.",
        "positive": "A General Limitation on Monte Carlo Algorithms of Metropolis Type: We prove that for any Monte Carlo algorithm of Metropolis type, the\nautocorrelation time of a suitable ``energy''-like observable is bounded below\nby a multiple of the corresponding ``specific heat''. This bound does not\ndepend on whether the proposed moves are local or non-local; it depends only on\nthe distance between the desired probability distribution $\\pi$ and the\nprobability distribution $\\pi^{(0)}$ for which the proposal matrix satisfies\ndetailed balance. We show, with several examples, that this result is\nparticularly powerful when applied to non-local algorithms."
    },
    {
        "anchor": "Many-flavor Schwinger model at finite chemical potential: We study thermodynamic properties of the Schwinger model on a torus with f\nflavors of massless fermions and flavor-dependent chemical potentials.\nGeneralizing the two-flavor case, we present a representation of the partition\nfunction in the form of a multidimensional theta function and show that the\nmodel exhibits a rich phase structure at zero temperature. The different\nphases, characterized by certain values of the particle numbers, are separated\nby first-order phase transitions. We work out the phase structure in detail for\nthree and four fermion flavors and conjecture, based on an exploratory\ninvestigation of the five, six, and eight flavor case, that the maximal number\nof coexisting phases at zero temperature grows exponentially with increasing f.",
        "positive": "Center vortex model for Sp(2) Yang-Mills theory: The question whether the center vortex picture of the strongly interacting\nvacuum can encompass the infrared dynamics of both SU(2) as well as Sp(2)\nYang-Mills theory is addressed. These two theories contain the same center\nvortex degrees of freedom, and yet exhibit deconfinement phase transitions of\ndifferent order. This is argued to be caused by the effective action governing\nthe vortices being different in the two cases. To buttress this argument, a\nrandom vortex world-surface model is constructed which reproduces available\nlattice data characterizing Sp(2) Yang-Mills confinement properties. A new\neffective action term which can be interpreted in terms of a vortex stickiness\nserves to realize a first-order deconfinement phase transition, as found in\nSp(2) Yang-Mills theory. Predictions are given for the behavior of the spatial\nstring tension at finite temperatures."
    },
    {
        "anchor": "Nuclear Liquid-Gas Transition in the Strong Coupling Regime of Lattice\n  QCD: The nuclear liquid-gas transition from a gas of hadrons to a nuclear phase\ncannot be determined numerically from conventional lattice QCD due to the\nsevere sign problem at large values of the baryon chemical potential. In the\nstrong coupling regime of lattice QCD with staggered quarks, the dual\nformulation is suitable to address the nuclear liquid gas transition. We\ndetermine this first order transition at low temperatures and as a function of\nthe quark mass and the inverse gauge coupling $\\beta$. We also determine the\nbaryon mass and discuss the nuclear interactions as a function of the quark\nmass, and compare to mean field results.",
        "positive": "On the infinite gradient-flow for the domain-wall formulation of chiral\n  lattice gauge theories: We examine the proposal by Grabowska and Kaplan (GK) to use the infinite\ngradient flow in the domain-wall formulation of chiral lattice gauge theories.\nWe consider the case of Abelian theories in detail, for which L\\\"uscher's exact\ngauge-invariant formulation is known, and we relate GK's formulation to\nL\\\"uscher's one. The gradient flow can be formulated for the admissible U(1)\nlink fields so that it preserves their topological charges. GK's effective\naction turns out to be equal to the sum of L\\\"uscher's gauge-invariant\neffective actions for the target Weyl fermions and the mirror \"fluffy\"\nfermions, plus the so-called measureterm integrated along the infinite gradient\nflow. The measure-term current is originally a local(analytic) and\ngauge-invariant functional of the admissible link field, given as a solution to\nthe local cohomology problem. However, with the infinite gradient flow, it\ngives rise to non-local(non-analytic) vertex functions which are not suppressed\nexponentially at large distance. The \"fluffy\" fermions remain as a source of\nnon-local contribution, which couple yet to the Wilson-line and magnetic-flux\ndegrees of freedom of the dynamical link field."
    },
    {
        "anchor": "Confinement in Coulomb gauge: We review our lattice results concerning the Gribov-Zwanziger confinement\nmechanism in Coulomb gauge. In particular, we verify the validity of Gribov's\nIR divergence condition for the Coulomb ghost form factor. We also show how the\nquark self-energy is, like that of the transverse gluon, IR divergent, thus\neffectively extending the Gribov-Zwanziger scenario to full QCD.",
        "positive": "Monte Carlo approach to turbulence: The behavior of the one-dimensional random-force-driven Burgers equation is\ninvestigated in the path integral formalism on a discrete space-time lattice.\nWe show that by means of Monte Carlo methods one may evaluate observables, such\nas structure functions, as ensemble averages over different field realizations.\nThe regularization of shock solutions to the zero-viscosity limit\n(Hopf-equation) eventually leads to constraints on lattice parameters required\nfor the stability of the simulations. Insight into the formation of localized\nstructures (shocks) and their dynamics is obtained."
    },
    {
        "anchor": "Spectral flow, condensate and topology in lattice QCD: We study the spectral flow of the Wilson-Dirac operator H(m) with and without\nan additional Sheikholeslami-Wohlert (SW) term on a variety of SU(3) lattice\ngauge field ensembles in the range $0\\le m \\le 2$. We have used ensembles\ngenerated from the Wilson gauge action, an improved gauge action, and several\ntwo-flavor dynamical quark ensembles. Two regions in $m$ provide a generic\ncharacterization of the spectrum. In region I defined by $m\\le m_1$, the\nspectrum has a gap. In region II defined by $m_1\\le m \\le 2$, the gap is\nclosed. The level crossings in H(m) that occur in region II correspond to\nlocalized eigenmodes and the localization size decreases monotonically with the\ncrossing point down to a size of about one lattice spacing. These small modes\nare unphysical, and we find the topological susceptibility is relatively stable\nin the part of region II where the small modes cross. We argue that the lack of\na gap in region II is expected to persist in the infinite volume limit at any\ngauge coupling. The presence of a gap is important for the implementation of\ndomain wall fermions.",
        "positive": "From Black Holes to Glueballs: The QCD_3 Tensor Glueball at Strong\n  Coupling: A strong coupling calculation of glueball masses based on the duality between\nsupergravity and Yang-Mills theory is presented. Earlier work is extended to\nnon-zero spin. Fluctuations in the gravitational metric lead to the 2^{++}\nstate on the leading Pomeron trajectory with a mass relation: m(0^{++}) <\nm(2^{++}) < m(1^{-+}). Contrary to expectation, the mass of our new 0^{++}\nstate (m^2=5.4573) associated with the graviton is smaller than the mass of the\n${\\tilde 0}^{++}$ state (m^2=11.588) from the dilaton, which in fact is exactly\ndegenerate with the tensor 2^{++}."
    },
    {
        "anchor": "Errata and Addenda to ``Anomaly Cancellation Condition in Lattice Gauge\n  Theory'': We correct some intermediate expressions and arguments in hep-lat/0002009\n(Nucl. Phys. B 585 (2000) 471--513). The main results do not change. We also\nmention some additional observations, including a constraint on a coefficient\nof the possible nontrivial anomaly which was not given in the paper.",
        "positive": "Five-Dimensional Gauge-Higgs Unification: A Standard Model-Like Spectrum: We study the viability of five-dimensional gauge theories as candidates for\nthe origin of the Higgs field and its mechanism for spontaneous symmetry\nbreaking. Within the framework of lattice field theory, we consider the\nsimplest model of an $SU(2)$ gauge theory. We construct this theory on a\nfive-dimensional orbifold which explicitly breaks the gauge symmetry to $U(1)$\nat the fixed points of the orbifold. Using anisotropic gauge couplings, we find\nthat this theory exhibits three distinct phases which we label as confined,\nHiggs and hybrid. Within the Higgs phase, close to the Higgs-hybrid phase\ntransition, we find that the ratio of the Higgs to gauge boson masses takes\nStandard Model-like values. Precisely in this region of the phase diagram, we\nfind dimensional reduction via localisation."
    },
    {
        "anchor": "Finite density simulations using a determinant estimator: Previous investigations have shown that the canonical approach to simulating\nQCD at finite density is promising. The algorithm we used in our earlier work\nemploys an exact calculation of the fermionic determinant which limits the size\nof the lattices we can simulate. Interesting questions can only be answered if\nwe simulate at larger volume. In this paper we explore an algorithm, Hybrid\nNoisy Monte Carlo, that employs a determinant estimator rather than an exact\ncalculation. We first present the technical aspects of the estimator, check\nthat the algorithm is correct by comparing it with our previous study, and then\ndiscuss its merits. We will also discuss the challenges faced when simulating\nlarger lattice volumes.",
        "positive": "An Ising-Anderson model of localisation in high-temperature QCD: We discuss a possible mechanism leading to localisation of the low-lying\nDirac eigenmodes in high-temperature lattice QCD, based on the spatial\nfluctuations of the local Polyakov lines in the partially ordered\nconfigurations above $T_c$. This mechanism provides a qualitative explanation\nof the dependence of localisation on the temperature and on the lattice\nspacing, and also of the phase diagram of QCD with an imaginary chemical\npotential. To test the viability of this mechanism we propose a\nthree-dimensional effective, Anderson-like model, mimicking the effect of the\nPolyakov lines on the quarks. The diagonal, on-site disorder is governed by a\nthree-dimensional Ising-like spin model with continuous spins. Our numerical\nresults show that localised modes are indeed present in the ordered phase of\nthe Ising model, thus supporting the proposed mechanism for localisation in\nQCD."
    },
    {
        "anchor": "Can we study Quark Matter in the Quenched Approximation?: We study a quenched SU(2) lattice gauge theory in which, in an attempt to\ndistinguish between timelike and spacelike gauge fields, the gauge ensemble\n{U_mu} is generated from a 3 dimensional gauge-Higgs model, the timelike link\nvariables being \"reconstructed\" from the Higgs fields. The resulting ensemble\nis used to study quenched quark propagation with non-zero chemical potential\nmu; in particular, the quark density, chiral and superfluid condensates, meson,\nbaryon and gauge-fixed quark propagators are all studied as functions of mu.\nWhile it proves possible to alter the strength of the inter-quark interaction\nby changing the parameters of the dimensionally reduced model, there is no\nevidence for any region of parameter space where quarks exhibit deconfined\nbehaviour or thermodynamic observables scale as if there were a Fermi surface.",
        "positive": "Thermodynamics of lattice QCD with two light quark flavours on a 16^3 x\n  8 lattice II: We have extended our earlier simulations of the high temperature behaviour of\nlattice QCD with two light flavours of staggered quarks on a $16^3 \\times 8$\nlattice to lower quark mass (m_q=0.00625). The transition from hadronic matter\nto a quark-gluon plasma is observed at $6/g^2=5.49(2)$ corresponding to a\ntemperature of $T_c \\approx 140$MeV. We present measurements of observables\nwhich probe the nature of the quark-gluon plasma and serve to distinguish it\nfrom hadronic matter. Although the transition is quite abrupt, we have seen no\nindications that it is first order."
    },
    {
        "anchor": "Theta dependence of 4D SU(N) gauge theories at finite temperature: We report a study of the dependence of 4D SU(N) gauge theories on the\ntopological theta term at finite temperature, and in particular in the large-N\nlimit. We show that the theta dependence drastically changes across the\ndeconfinement transition. The low-temperature phase is characterized by a\nlarge-N scaling with theta/N as relevant variable, while in the\nhigh-temperature phase the free energy is essentially determined by the dilute\ninstanton-gas approximation, with a simple theta dependence of the free-energy\ndensity proportional to 1-Cos(theta).",
        "positive": "Simulating lattice QCD at finite temperature and zero quark mass: We simulate lattice QCD with an irrelevant chiral 4-fermion interaction which\nallows us to simulate at zero quark mass. This enables us to study the\nfinite-temperature chiral-symmetry-restoring phase transition for 2 massless\nquark flavours, which is believed to be second order. In particular, it enables\nus to estimate the critical exponents which characterize the universality class\nof this transition. Our earlier simulations on $N_t=4$ and $N_t=6$ lattices\nrevealed that finite lattice-spacing artifacts on such coarse lattices affect\nthe nature of the transition. We are now simulating on $N_t=8$ lattices ($12^3\n\\times 8$, $16^3 \\times 8$ and $24^3 \\times 8$ lattices) where we expect to\nexpose the continuum behaviour of this transition."
    },
    {
        "anchor": "Bosonization and Cluster Updating of Lattice Fermions: A lattice fermion model is formulated in Fock space using the Jordan-Wigner\nrepresentation for the fermion creation and annihilation operators. The\nresulting path integral is a sum over configurations of lattice site occupation\nnumbers $n(x,t) = 0,1$ which may be viewed as bosonic Ising-like variables.\nHowever, as a remnant of Fermi statistics a nonlocal sign factor arises for\neach configuration. When this factor is included in measured observables the\nbosonic occupation numbers interact locally, and one can use efficient cluster\nalgorithms to update the bosonized variables.",
        "positive": "GPU computing for 2-d spin systems: CUDA vs OpenGL: In recent years the more and more powerful GPU's available on the PC market\nhave attracted attention as a cost effective solution for parallel (SIMD)\ncomputing. CUDA is a solid evidence of the attention that the major companies\nare devoting to the field. CUDA is a hardware and software architecture\ndeveloped by Nvidia for computing on the GPU. It qualifies as a friendly\nalternative to the approach to GPU computing that has been pioneered in the\nOpenGL environment. We discuss the application of both the CUDA and the OpenGL\napproach to the simulation of 2-d spin systems (XY model)."
    },
    {
        "anchor": "Dynamics of the 2d Potts model phase transition: The dynamics of 2d Potts models, which are temperature driven through the\nphase transition using updating procedures in the Glauber universality class,\nis investigated. We present calculations of the hysteresis for the (internal)\nenergy and for Fortuin-Kasteleyn clusters. The shape of the hysteresis is used\nto define finite volume estimators of physical observables, which can be used\nto study the approach to the infinite volume limit. We compare with equilibrium\nconfigurations and the preliminary indications are that the dynamics leads to\nconsiderable alterations of the statistical properties of the configurations\nstudied.",
        "positive": "Chiral Dynamics With Wilson Fermions: Close to the continuum the lattice spacing affects the smallest eigenvalues\nof the Wilson Dirac operator in a very specific manner determined by the way in\nwhich the discretization breaks chiral symmetry. These effects can be computed\nanalytically by means of Wilson chiral perturbation theory and Wilson random\nmatrix theory. A number of insights on chiral Dynamics with Wilson fermions can\nbe obtained from the computation of the microscopic spectrum of the Wilson\nDirac operator. For example, the unusual volume scaling of the smallest\neigenvalues observed in lattice simulations has a natural explanation. The\ndynamics of the eigenvalues of the Wilson Dirac operator also allow us to\ndetermine the additional low energy constants of Wilson chiral perturbation\ntheory and to understand why the Sharpe-Singleton scenario is only realized in\nunquenched simulations."
    },
    {
        "anchor": "The distribution amplitude of the $\u03b7_c$ meson: We report on the first lattice determination of the pseudoscalar meson\n$\\eta_c$ light-cone distribution amplitude, using a set of three CLS $N_f=2$\nensembles at a pion mass $m_{\\pi} \\sim 270~\\text{MeV}$ and lattice spacings $a\n\\sim 0.076~\\text{fm}$, $0.066~\\text{fm}$ and $0.049~\\text{fm}$. Employing Short\nDistance Factorization, we extract the pseudo-DA on the lattice for Ioffe times\n$\\nu \\leq 4.5$, and the various lattice spacings allow us to take the continuum\nlimit. We employ a basis of Jacobi polynomials to parametrize the distribution\namplitude, which allows to express the matching to the pseudo distribution in\nclosed form, and we observe a strong effect which we attribute to the heavy\ncharm-quark mass.",
        "positive": "Ergodic SO(3), monopole condensation and vortex free energy: We study the continuum limit of adjoint SU(2) LGT by means of a suppression\nterm for Z2 monopoles. High barriers for tunnelling among different twist\nsectors are overcome through parallel tempering. Monopole condensation is used\nto study the deconfinement transition and the properties of the confined phase.\nErgodicity in summing over all twist sectors allows an unbiased measure of the\n't Hooft vortices free energy. Its behaviour in the SO(3) confined phase hints\nat differences from what conjectured for semi-integer discretizations."
    },
    {
        "anchor": "Two-colour QCD at non-zero quark-number density: We have simulated two-colour four-flavour QCD at non-zero chemical potential\n$\\mu$ for quark number. Simulations were performed on $8^4$ and $12^3 \\times\n24$ lattices. Clear evidence was seen for the formation of a colourless diquark\ncondensate which breaks quark number spontaneously, for $\\mu > \\mu_c \\sim\nm_\\pi/2$. The transition appears to be second order. We have measured the\nspectrum of scalar and pseudoscalar bosons which shows clear evidence for the\nexpected Goldstone boson. Our results are in qualitative agreement with those\nfrom effective Lagrangians for the potential Goldstone excitations of this\ntheory.",
        "positive": "Evaluating topological charge density with symmetric multi-probing\n  method: We evaluated the topological charge density of SU(3) gauge fields on lattice\nby calculating the trace of overlap Dirac matrix employing symmetric\nmulti-probing(SMP) method with 3 modes. Since the topological charge $Q$ for a\ngiven lattice configuration must be an integer number, it's easy to estimate\nthe systematic error (the deviation of $Q$ to nearest integer). The results\nshowed high efficiency and accuracy in calculating the trace of the inverse of\na large sparse matrix with locality by using SMP sources, compared with that\nusing point sources. We also showed the correlation between the errors and\nprobing scheme parameter $r_{\\mathrm{min}}$ as well as lattice volume $N_{L}$\nand lattice spacing $a$. It was found that the computing time of calculating\nthe trace by employing SMP sources is less dependent on $N_{L}$ than that by\nusing point sources. Therefore the SMP method is very suitable for calculations\non large lattices."
    },
    {
        "anchor": "QCD with Adjoint Scalars in 2D: Properties in the Colourless Scalar\n  Sector: We present a numerical study of an SU(3) gauged 2D model for adjoint scalar\nfields, defined by dimensional reduction of pure gauge QCD in (2+1)D at high\ntemperature. In the symmetric phase of its global Z_2 symmetry, two colourless\nboundstates, even and odd under Z_2, are identified. Their respective\ncontributions (poles) in correlation functions of local composite operators A_n\nof degree n=2p and 2p+1 in the scalar fields (p=1,2) fulfill factorization. The\ncontributions of two particle states (cuts) are detected. Their size agrees\nwith estimates based on a meanfield-like decomposition of the p=2 operators\ninto polynomials in p=1 operators. No sizable signal in any A_n correlation can\nbe attributed to 1/n times a Debye screening length associated with n\nelementary fields. These results are quantitatively consistent with the picture\nof scalar ``matter'' fields confined within colourless boundstates whose\nresidual ``strong'' interactions are very weak.",
        "positive": "Perturbative investigation of Wilson-line operators in Parton Physics: We investigate the renormalization of a class of gauge-invariant nonlocal\nquark bilinear operators, including a finite-length Wilson-line (called\nWilson-line operators). The matrix elements of these operators are involved in\nthe recent \"quasi-distribution\" approach for computing light-cone distributions\nof Hadronic Physics on the lattice. We consider two classes of Wilson-line\noperators: straight-line and staple-shaped operators, which are related to the\nparton distribution functions (PDFs) and transverse momentum-dependent\ndistributions (TMDs), respectively. We present our one-loop results for the\nconversion factors of straight-line operators between the RI' (appropriate for\nnonperturbative renormalization on the lattice) and MSbar (typically used in\nphenomenology) renormalization schemes in the presence of nonzero quark masses.\nIn addition, we present the first results of our preliminary work for the\nrenormalization of staple-shaped operators both in continuum (Dimensional\nRegularization) and lattice (Wilson/clover fermions and Symanzik improved\ngluons) regularizations. We identify the observed mixing pairs among these\noperators, which must be disentangled in the nonperturbative investigations of\nheavy-quark quasi-PDFs and of light-quark quasi-TMDs."
    },
    {
        "anchor": "Precision for B-meson matrix elements: We demonstrate how HQET and the Step Scaling Method for B-physics, pioneered\nby the Tor Vergata group, can be combined to reach a further improved\nprecision. The observables considered are the mass of the b-quark and the\nB_s-meson decay constant. The demonstration is carried out in quenched lattice\nQCD. We start from a small volume, where one can use a standard O(a)-improved\nrelativistic action for the b-quark, and compute two step scaling functions\nwhich relate the observables to the large volume ones. In all steps we\nextrapolate to the continuum limit, separately in HQET and in QCD for masses\nbelow m_b. The physical point m_b is then reached by an interpolation of the\ncontinuum results in 1/m. The essential, expected and verified, feature is that\nthe step scaling fuctions have a weak mass-dependence resulting in an easy\ninterpolation to the physical point. With r_0=0.5fm and the experimental B_s\nand K masses as input, we find F_Bs=191(6)MeV and the renormalization group\ninvariant mass M_b=6.88(10)GeV, translating into m_b(m_b)=4.42(6)GeV in the\nMSbar scheme. This approach seems very promising for full QCD.",
        "positive": "Overlap fermions on a twisted mass sea: We present first results of a mixed action project. We analyze gauge\nconfigurations generated with two flavors of dynamical twisted mass fermions.\nNeuberger's overlap Dirac operator is used for the valence sector. The various\nchoices in the setup of the simulation are discussed. We employ chiral\nperturbation theory to describe the effects of using different actions in the\nsea and valence sector at non-zero lattice spacing."
    },
    {
        "anchor": "Electromagnetic and spin polarisabilities in lattice QCD: We discuss the extraction of the electromagnetic and spin polarisabilities of\nnucleons from lattice QCD. We show that the external field method can be used\nto measure all the electromagnetic and spin polarisabilities including those of\ncharged particles. We then turn to the extrapolations required to connect such\ncalculations to experiment in the context of finite volume chiral perturbation\ntheory. We derive results relevant for lattice simulations of QCD,\npartially-quenched QCD and quenched QCD. Our results for the polarisabilities\nshow a strong dependence on the lattice volume and quark masses, typically\ndiffering from the infinite volume limit by ~10% for current lattice volumes\nand quark masses.",
        "positive": "Pion form factor with twisted mass QCD: The pion form factor is calculated using quenched twisted mass QCD with\nbeta=6.0 and maximal twisting angle omega=pi/2. Two pion masses and several\nvalues of momentum transfer are considered. The momentum averaging procedure of\nFrezzotti and Rossi is used to reduce lattice spacing errors, and numerical\nresults are consistent with the expected O(a) improvement."
    },
    {
        "anchor": "Correlation of the ghost and the quark in the lattice Landau gauge QCD: Effects of the quark field on the ghost propagator of the lattice Landau\ngauge are investigated by using the quenched gauge configuration of SU(2) first\ncopy and the parallel tempering (PT) gauge fixed samples, quenched SU(3) $56^4$\nconfiguration and unquenched SU(3) configurations produced by the MILC\ncollaboration.\n  We measure color symmetric and color antisymmetric ghost propagator and the\nBinder cumulant of $l^1$ norm and $l^2$ norm of color antisymmetric ghost\npropagator and investigate deviation from that of Gaussian distribution.\n  The dynamical quarks make color antisymmetric ghost propagator closer to\nGaussian distribution and Kugo-Ojima color confinement parameter $c$ closer to\n1.",
        "positive": "Volume dependence of two-dimensional large-N QCD with a nonzero density\n  of baryons: We take a first step towards the solution of QCD in 1+1 dimensions at nonzero\ndensity. We regularize the theory in the UV by using a lattice and in the IR by\nputting the theory in a box of spatial size L. After fixing to axial gauge we\nuse the coherent states approach to obtain the large-N classical Hamiltonian H\nthat describes color neutral quark-antiquark pairs interacting with spatial\nPolyakov loops in the background of baryons. Minimizing H we get a regularized\nform of the `t Hooft equation that depends on the expectation values of the\nPolyakov loops. Analyzing the L-dependence of this equation we show how volume\nindependence, a la Eguchi and Kawai, emerges in the large-N limit, and how it\ndepends on the expectation values of the Polyakov loops. We describe how this\nindependence relies on the realization of translation symmetry, in particular\nwhen the ground state contains a baryon crystal. Finally, we remark on the\nimplications of our results on studying baryon density in large-N QCD within\nsingle-site lattice theories, and on some general lessons concerning the way\nfour-dimensional large-N QCD behaves in the presence of baryons."
    },
    {
        "anchor": "THE ELECTROWEAK PHASE TRANSITION ON THE LATTICE: The finite temperature electroweak phase transition is studied on the\nlattice. The results of the simulations obtained by the 3-dimensional effective\ntheories and the 4-dimensional SU(2)-Higgs model are reviewed.",
        "positive": "Three-gluon vertex in Landau-gauge from quenched-lattice QCD in general\n  kinematics: We report on a novel and extensive lattice QCD analysis for the three-gluon\nvertex from quenched lattice-QCD simulations. Using standard Wilson action, we\nhave computed the three-gluon vertex beyond the usual kinematic restriction to\nthe symmetric $(q^2 = r^2 = p^2)$ and soft-gluon $(p = 0)$ cases where it\ndepends on a single momentum scale. The so-dubbed bisectoral case $(r^2 = q^2\n\\ne p^2)$, where the transversely projected vertex can be cast in terms of\nthree independent tensors, have been the object of a recent exhaustive\nscrutiny, also shown in this communication. Herein, beyond this special case,\nresults for kinematic configurations with three different squared momenta are\nalso presented. All data considered, the lattice estimate of the three-gluon\nvertex exhibits a clear dominance of the tree-level tensor form factor."
    },
    {
        "anchor": "Lattice Predictions for Hybrids and Glueballs: I review the results from lattice gauge theory for the properties of the\nlight 1-+ exotic state and 0++ glueball.",
        "positive": "Investigation of the hadronic light-by-light contribution to the muon\n  $g{-}2$ using staggered fermions: Hadronic contributions dominate the uncertainty of the standard model\nprediction for the anomalous magnetic moment of the muon. In this work, we\ndescribe an ongoing lattice calculation of the hadronic light-by-light\ncontribution, performed with staggered fermions. The presence of quarks with\ndifferent tastes complicates the analysis of the position-space correlation\nfunction. We present a suitable adaption of the \"Mainz method\". As a first\nnumerical test, we reproduce the well-known lepton-loop contribution. Results\nat a single lattice spacing for the light quark contribution, using two\nvolumes, are then discussed. Our study of the long distance behavior and\nfinite-volume effects is supplemented by considering the contribution of the\nlight pseudoscalar-pole. The corresponding transition form factors have been\nevaluated in previous simulations on the same ensembles."
    },
    {
        "anchor": "Non-perturbative tests of continuum HQET through small-volume\n  two-flavour QCD: We study the heavy quark mass dependence of selected observables constructed\nfrom heavy-light meson correlation functions in small-volume two-flavour\nlattice QCD after taking the continuum limit. The light quark mass is tuned to\nzero, whereas the range of available heavy quark masses $m_h$ covers a region\nextending from around the charm to beyond the bottom quark mass scale. This\nallows entering the asymptotic mass-scaling regime as $1/m_h \\to 0$ and\nperforming well-controlled extrapolations to the infinite-mass limit. Our\nresults are then compared to predictions obtained in the static limit of\ncontinuum Heavy Quark Effective Theory (HQET), in order to verify\nnon-perturbatively that HQET is an effective theory of QCD. While in general we\nobserve a nice agreement at the few-% level, we find it to be less convincing\nfor the small-volume pseudoscalar decay constant when perturbative matching is\ninvolved.",
        "positive": "Mixing Scenarios for Lattice String Breaking: We present some simple scenarios for string breaking on the lattice based on\na crude strong coupling model introduced previously. We review the dependence\nof the model on lattice spacing and extend it to include degenerate dynamical\nquarks and also meson exchange diagrams. A comparison is made between quenched\nand unquenched calculations. We examine string breaking in the presence of a\nstatic quark-diquark system, a situation that is specific to SU(3)."
    },
    {
        "anchor": "On the exponential bound in four dimensional simplicial gravity: Simplicial quantum gravity has been proposed as a regularization for four\ndimensional quantum gravity. The partition function is constructed by\nperforming a weighted sum over all triangulations of the 4-sphere. The model is\nwell-defined only if the number of such triangulations consisting of $N$\nsimplexes is exponentially bounded. Numerical simulations seem so far to favor\nsuch a bound.",
        "positive": "The bulk transition of many-flavour QCD and the search for a UVFP at\n  strong coupling: We explore the nature of the bulk transition observed at strong coupling in\nthe SU(3) gauge theory with Nf=12 fermions in the fundamental representation.\nThe transition separates a weak coupling chirally symmetric phase from a strong\ncoupling chirally broken phase and is compatible with the scenario where\nconformality is restored by increasing the flavour content of a non abelian\ngauge theory. We explore the intriguing possibility that the observed bulk\ntransition is associated with the occurrence of an ultraviolet fixed point\n(UVFP) at strong coupling, where a new theory emerges in the continuum."
    },
    {
        "anchor": "Variance reduction with practical all-to-all lattice propagators: We discuss all-to-all quark propagator techniques in two (related) contexts\nwithin Lattice QCD: the computation of closed quark propagators, and\napplications to the so-called \"eye diagrams\" appearing in the computation of\nnon-leptonic kaon decay amplitudes. Combinations of low-mode averaging and\ndiluted stochastic volume sources that yield optimal signal-to-noise ratios for\nthe latter problem are developed. We also apply a recently proposed probing\nalgorithm to compute directly the diagonal of the inverse Dirac operator, and\ncompare its performance with that of stochastic methods. At fixed computational\ncost the two procedures yield comparable signal-to-noise ratios, but probing\nhas practical advantages which make it a promising tool for a wide range of\napplications in Lattice QCD.",
        "positive": "Feynman--Hellmann approach to transition matrix elements and\n  quasi-degenerate energy states: The Feynman--Hellmann approach to computing matrix elements in lattice QCD by\nfirst adding a perturbing operator to the action is described using the\ntransition matrix and the Dyson expansion formalism. This perturbs the energies\nin the two-point baryon correlation function, from which the matrix element can\nbe obtained. In particular at leading order in the perturbation we need to\ndiagonalise a matrix of near-degenerate energies. While the method is general\nfor all hadrons, we apply it here to a study of a Sigma to Nucleon baryon\ntransition vector matrix element."
    },
    {
        "anchor": "Systematic uncertainties in the precise determination of the strangeness\n  magnetic moment of the nucleon: Systematic uncertainties in the recent precise determination of the\nstrangeness magnetic moment of the nucleon are identified and quantified. In\nsummary, G_M^s = -0.046 \\pm 0.019 \\mu_N.",
        "positive": "Determination of the chiral condensate from 2+1-flavor lattice QCD: We perform a precise calculation of the chiral condensate in QCD using\nlattice QCD with 2+1 flavors of dynamical overlap quarks. Up and down quark\nmasses cover a range between 3 and 100 MeV on a 16^3x48 lattice at a lattice\nspacing around 0.11 fm. At the lightest sea quark mass, the finite volume\nsystem on the lattice is in the epsilon-regime. By matching the low-lying\neigenvalue spectrum of the Dirac operator with the prediction of chiral\nperturbation theory at the next-to-leading order, we determine the chiral\ncondensate in 2+1-flavor QCD with strange quark mass fixed at its physical\nvalue as Sigma (MS-bar at 2 GeV) = [242(04)(^+19_-18}) MeV}]^3, where the\nerrors are statistical and systematic, respectively."
    },
    {
        "anchor": "Gauge invariant determination of charged hadron masses: In this paper we show, for the first time, that charged-hadron masses can be\ncalculated on the lattice without relying on gauge fixing at any stage of the\ncalculations. In our simulations we follow a recent proposal and formulate full\nQCD+QED on a finite volume, without spoiling locality, by imposing C-periodic\nboundary conditions in the spatial directions. Electrically charged states are\ninterpolated with a class of operators, originally suggested by Dirac and built\nas functionals of the photon field, that are invariant under local gauge\ntransformations. We show that the quality of the numerical signal of\ncharged-hadron masses is the same as in the neutral sector and that\ncharged-neutral mass splittings can be calculated with satisfactory accuracy in\nthis setup. We also discuss how to describe states of charged hadrons with real\nphotons in a fully gauge-invariant way by providing a first evidence that the\nproposed strategy can be numerically viable.",
        "positive": "Gluon Propagator on Coarse Lattices in Laplacian Gauges: The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau\ngauge in the asymptotic limit. Like Landau gauge, it respects Lorentz\ninvariance, but it is free of Gribov copies; the gauge fixing is unambiguous.\nIn this paper we study the infrared behavior of the lattice gluon propagator in\nLaplacian gauge by using a variety of lattices with spacings from $a = 0.125$\nto 0.35 fm, to explore finite volume and discretization effects. Three\ndifferent implementations of the Laplacian gauge are defined and compared. The\nLaplacian gauge propagator has already been claimed to be insensitive to finite\nvolume effects and this is tested on lattices with large volumes."
    },
    {
        "anchor": "The Kaon B-Parameter in Staggered Chiral Perturbation Theory: We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered\nchiral perturbation theory. We extend the usual power counting to include the\neffects of using perturbative (rather than non-perturbative) matching factors.\nTaste breaking enters through the O(a^2) terms in the effective action, through\nmixing with higher-dimension operators, and through the truncation of matching\nfactors. These effects cause mixing with several additional operators,\ncomplicating the chiral and continuum extrapolations. We summarize the results\nhere; all details can be found in hep-lat/0507012.",
        "positive": "Towards glueball masses of large-$N~\\mathrm{SU}(N)$ Yang-Mills theories\n  without topological freezing via parallel tempering on boundary conditions: Standard local updating algorithms experience a critical slowing down close\nto the continuum limit, which is particularly severe for topological\nobservables. In practice, the Markov chain tends to remain trapped in a fixed\ntopological sector. This problem further worsens at large $N$, and is known as\n$\\mathit{topological}~\\mathit{freezing}$. To mitigate it, we adopt the parallel\ntempering on boundary conditions proposed by M. Hasenbusch. This algorithm\nallows to obtain a reduction of the auto-correlation time of the topological\ncharge up to several orders of magnitude. With this strategy we are able to\nprovide the first computation of low-lying glueball masses at large $N$ free of\nany systematics related to topological freezing."
    },
    {
        "anchor": "Constituent Gluon Content of the Static Quark-Antiquark State in Coulomb\n  Gauge: Motivated by the gluon-chain model of flux tube formation, we compute and\ndiagonalize the transfer matrix in lattice SU(2) gauge theory for states\ncontaining heavy static quark-antiquark sources, with separations up to one\nfermi. The elements of the transfer matrix are calculated by variational Monte\nCarlo methods, in a basis of states obtained by acting on the vacuum state with\nzero, one, and two-gluon operators in Coulomb gauge. The color Coulomb\npotential is obtained from the zero gluon to zero gluon element of the transfer\nmatrix, and it is well-known that while this potential is asymptotically\nlinear, it has a slope which is two to three times larger than the standard\nasymptotic string tension. We show that the addition of one and two gluon\nstates results in a potential which is still linear, but the disagreement with\nthe standard asymptotic string tension is reduced to 38% at the largest lattice\ncoupling we have studied.",
        "positive": "Thermodynamics of lattice QCD with 3 flavours of colour-sextet quarks\n  II: N_t=6 and N_t=8: We have been studying QCD with 2 flavours of colour-sextet quarks as a\ncandidate walking-Technicolor theory using lattice-QCD simulations. The\nevolution of the coupling constant with lattice spacing is measured at the\nfinite-temperature chiral transition to determine if this theory is\nasymptotically free and hence QCD-like. The lattice spacing is varied by\nchanging the number of lattice sites, $N_t$, in the Euclidean time direction.\nQCD with 3 flavours is studied for comparison. Since this theory is expected to\nbe conformal, with an infrared fixed point, the coupling constant at the chiral\ntransition should approach a non-zero value as $N_t$ becomes large. Our earlier\nsimulations on lattices with $N_t=4$ and $N_t=6$ exhibited a significant\ndecrease in coupling at the chiral transition as $N_t$ was increased. We have\nnow extended these simulations to $N_t=8$, and performed additional simulations\nat $N_t=6$ to measure the coupling constant at the chiral transition more\nprecisely. These indicate that while there is an appreciable decrease in\ncoupling between $N_t=6$ and $N_t=8$, this is much smaller than that between\n$N_t=4$ and $N_t=6$. Thus we are hopeful that we are approaching the\nlarge-$N_t$ limit. However, further simulations at larger $N_t$(s) are needed."
    },
    {
        "anchor": "Matrix elements of bound states in a finite volume: Recently, a framework was developed for studying form factors of two-body\nstates probed with an external current. Finite volume matrix elements that may\nbe computed via lattice QCD are converted to infinite volume generalized form\nfactors. These generalized form factors allow us to study the structure of\ncomposite states. In this talk, we consider the application of this formalism\nto bound states, and compare the leading finite volume effects to the general\nresults of the framework. Specifically, we consider the implications for the\ndeuteron at the physical point, and conclude that it's necessary to use the\nfull formalism to not be saturated by systematics",
        "positive": "Charmed spectroscopy from a nonperturbatively determined relativistic\n  heavy quark action in full QCD: We present a preliminary calculation of the charmed meson spectrum using the\n2+1 flavor domain wall fermion lattice configurations currently being generated\nby the RBC and UKQCD collaborations. The calculation is performed using the\n3-parameter, relativistic heavy quark action with nonperturbatively determined\ncoefficients. We will also demonstrate a step-scaling procedure for determining\nthese coefficients nonperturbatively using a series of quenched, gauge field\nensembles generated for three different lattice spacings."
    },
    {
        "anchor": "Symmetries of Thirring models on 3d lattices: We review some recent developments about strongly interacting relativistic\nFermi theories in three spacetime dimensions. These models realize the\nasymptotic safety scenario and are used to describe the low-energy properties\nof Dirac materials in condensed matter physics. We begin with a general\ndiscussion of the symmetries of multi-flavor Fermi systems in arbitrary\ndimensions. Then we review known results about the critical flavor number\n$N_\\mathrm{crit}$ of Thirring models in three dimensions. Only models with\nflavor number below $N_\\mathrm{crit}$ show a phase transition from a\nsymmetry-broken strong-coupling phase to a symmetric weak-coupling phase.\nRecent simulations with chiral fermions show that $N_\\mathrm{crit}$ is smaller\nthan previously extracted with various non-perturbative methods. Our\nsimulations with chiral SLAC fermions reveal that for four-component flavors\n$N_\\mathrm{crit}=0.80(4)$. This means that all reducible Thirring models with\n$\\Nr=1,2,3,\\dots$ show no phase transition with order parameter. Instead we\ndiscover footprints of phase transitions without order parameter. These new\ntransitions are probably smooth and could be used to relate the lattice\nThirring models to Thirring models in the continuum. For a single irreducible\nflavor, we provide previously unpublished values for the critical couplings and\ncritical exponents.",
        "positive": "Effective Sampling of Random Surfaces by Baby Universe Surgery: We propose a new, very efficient algorithm for sampling of random surfaces in\nthe Monte Carlo simulations, based on so-called baby universe surgery, i.e.\ncutting and pasting of baby universes. It drastically reduces slowing down as\ncompared to the standard local flip algorithm, thereby allowing simulations of\nlarge random surfaces coupled to matter fields. As an example we investigate\nthe efficiency of the algorithm for 2d simplicial gravity interacting with a\none-component free scalar field. The radius of gyration is the slowest mode in\nthe standard local flip/shift algorithm. The use of baby universe surgery\ndecreases the autocorrelation time by three order of magnitude for a random\nsurface of $0.5 \\cdot 10^5$ triangles, where it is found to be $\\tau_{int} =\n150 \\pm 31$ sweeps."
    },
    {
        "anchor": "Beyond-the-Standard-Model matrix elements with the gradient flow: At the Forschungszentrum Juelich (FZJ) we have started a long-term program\nthat aims to determine beyond-the-Standard-Model (BSM) matrix elements using\nthe gradient flow, and to understand the impact of BSM physics in nucleon and\nnuclear observables. Using the gradient flow, we propose to calculate the QCD\ncomponent of key beyond the Standard Model (BSM) matrix elements related to\nquark and strong theta CP violation and the strange content within the nucleon.\nThe former set of matrix elements impacts our understanding of Electric Dipole\nMoments (EDMs) of nucleons and nuclei (a key signature of BSM physics), while\nthe latter contributes to elastic recoil of Dark Matter particles off nucleons\nand nuclei. If successful, these results will lay the foundation for extraction\nof BSM observables from future low-energy, high-intensity and high-accuracy\nexperimental measurements.",
        "positive": "The $\u03b8$-term, CP$^{N-1}$ Model and the Inversion Approach in the\n  Imaginary $\u03b8$ Method: The weak coupling region of CP$^{N-1}$ lattice field theory with the\n$\\theta$-term is investigated. Both the usual real theta method and the\nimaginary theta method are studied. The latter was first proposed by Bhanot and\nDavid. Azcoiti et al. proposed an inversion approach based on the imaginary\ntheta method. The role of the inversion approach is investigated in this paper.\nA wide range of values of $h=-{\\rm Im} \\theta$ is studied, where $\\theta $\ndenotes the magnitude of the topological term. Step-like behavior in the\n$x$-$h$ relation (where $x=Q/V$, $Q$ is the topological charge, and $V$ is the\ntwo dimensional volume) is found in the weak coupling region. The physical\nmeaning of the position of the step-like behavior is discussed. The inversion\napproach is applied to weak coupling regions."
    },
    {
        "anchor": "Anomalous Dimensions at an Infrared Fixed Point in an SU($N_c$) Gauge\n  Theory with Fermions in the Fundamental and Antisymmetric Tensor\n  Representations: We present scheme-independent calculations of the anomalous dimensions\n$\\gamma_{\\bar\\psi\\psi,IR}$ and $\\gamma_{\\bar\\chi\\chi,IR}$ of fermion bilinear\noperators $\\bar\\psi\\psi$ and $\\bar\\chi\\chi$ at an infrared fixed point in an\nasymptotically free SU($N_c$) gauge theory with massless Dirac fermion content\nconsisting of $N_F$ fermions $\\psi^a_i$ in the fundamental representation and\n$N_{A_2}$ fermions $\\chi^{ab}_j$ in the antisymmetric rank-2 tensor\nrepresentation, where $i,j$ are flavor indices. For the case $N_c=4$, $N_F=4$,\nand $N_{A_2}=4$, we compare our results with values of these anomalous\ndimensions measured in a recent lattice simulation and find agreement.",
        "positive": "Three-Loop Results on the Lattice: We present some new three-loop results in lattice gauge theories, for the\nFree Energy and for the Topological Susceptibility. These results are an\noutcome of a scheme which we are developing (using a symbolic manipulation\nlanguage), for the analytic computation of renormalization functions on the\nlattice."
    },
    {
        "anchor": "Multi-mass solvers for lattice QCD on GPUs: Graphical Processing Units (GPUs) are more and more frequently used for\nlattice QCD calculations. Lattice studies often require computing the quark\npropagators for several masses. These systems can be solved using multi-shift\ninverters but these algorithms are memory intensive which limits the size of\nthe problem that can be solved using GPUs. In this paper, we show how to\nefficiently use a memory-lean single-mass inverter to solve multi-mass\nproblems. We focus on the BiCGstab algorithm for Wilson fermions and show that\nthe single-mass inverter not only requires less memory but also outperforms the\nmulti-shift variant by a factor of two.",
        "positive": "SU(3) lattice QCD study of the gluon propagator in maximally Abelian\n  gauge: off-diagonal gluon mass generation and infrared Abelian dominance: We investigate gluon propagators and the effective mass of the gluon fields\nin the MA gauge with U(1)$_3 \\times$ U(1)$_8$ Landau gauge fixing in SU(3)\nlattice QCD. The Monte Carlo simulation is performed on $16^4$ at $\\beta$=5.7,\n5.8 and 6.0 and $32^4$ at $\\beta=$5.8 and 6.0 at the quenched level. To\ncalculate the propagators, we adopt a method to extract gauge fields from\nlink-variables analytically in the SU(3) case. The off-diagonal gluons behave\nas massive vector bosons with the approximate effective mass $M_{\\rm off}\n\\simeq 1.1 - 1.2 {\\rm GeV}$ in the region of $r = 0.3 - 0.8 {\\rm fm}$, and the\npropagation is limited within a short range. On the other hand, the diagonal\ngluons behave as light vector bosons with $M_{\\rm diag}\\simeq 0.3 {\\rm GeV} $\nand the propagation of diagonal gluons remains even in a large range. In this\nway, infrared Abelian dominance is shown in terms of short-range propagation of\noff-diagonal gluons. Furthermore, we investigate the functional form of the\noff-diagonal gluon propagator. The functional form is well described by the\nfour-dimensional Euclidean Yukawa-type function ${\\rm exp}(-m_{\\rm off} r)/r$\nwith $m_{\\rm off} = 1.3 -1.4 {\\rm GeV}$ for $r = 0.1- 0.8{\\rm fm}$. This also\nindicates that the spectral function of off-diagonal gluons has the\nnegative-value region."
    },
    {
        "anchor": "Finite-volume matrix elements of two-body states: In this talk, we present a framework for studying structural information of\nresonances and bound states coupling to two-hadron scattering states. This\nmakes use of a recently proposed finite-volume formalism to determine a class\nof observables that are experimentally inaccessible but can be accessed via\nlattice QCD. In particular, we shown that finite-volume two-body matrix\nelements with one current insertion can be directly related to scattering\namplitudes coupling to the external current. For two-hadron systems with\nresonances or bound states, one can extract the corresponding form factors of\nthese from the energy-dependence of the amplitudes.",
        "positive": "Dynamical simulations of QCD at finite temperature with a truncated\n  perfect action: The Hypercube operator determines a variant of the approximate, truncated\nperfect fermion action. In this pilot study we are going to report on first\nexperiences in dynamical QCD simulations with the Hypercube fermions. We apply\nthis formulation in an investigation of the finite temperature transition for\ntwo flavours. On lattices of size $8^3\\times 4$ we explore the phase diagram.\nPhysical scales are estimated from pseudoscalar and vector meson masses\nobtained on $8^3\\times 16$ lattices. We observe the presence of a metastability\nregion but do not find evidence for an Aoki phase. The Hypercube operator\nallows us to simulate at ratios of pseudoscalar to vector meson masses at least\nas small as 0.8 at the thermal crossover at $N_t=4$, which renders this\nformulation cheaper than the Wilson like fermions."
    },
    {
        "anchor": "New conjecture on exact Dirac zero-modes of lattice fermions: We propose a new conjecture on the relation between the species doubling of\nlattice fermions and the topology of manifold on which the fermion action is\ndefined. Our conjecture claims that the maximal number of fermion species on a\nfinite-volume and finite-spacing lattice defined by discretizing a\n$D$-dimensional manifold is equal to the summation of the Betti numbers of the\nmanifold. We start with reconsidering species doubling of naive fermions on the\nlattices whose topologies are torus ($T^{D}$), hyperball ($B^D$) and their\ndirect-product space ($T^{D} \\times B^{d}$). We find that the maximal number of\nspecies is in exact agreement with the sum of Betti numbers $\\sum^{D}_{r=0}\n\\beta_{r}$ for these manifolds. Indeed, the $4D$ lattice fermion on torus has\nup to $16$ species while the sum of Betti numbers of $T^4$ is $16$. This\ncoincidence holds also for the $D$-dimensional hyperball and their\ndirect-product space $T^{D} \\times B^{d}$. We study several examples of lattice\nfermions defined on discretized hypersphere ($S^{D}$), and find that it has up\nto $2$ species, which is the same number as the sum of Betti numbers of\n$S^{D}$. From these facts, we conjecture the equivalence of the maximal number\nof fermion species and the summation of Betti numbers. We discuss a program for\nproof of the conjecture in terms of Hodge theory and spectral graph theory.",
        "positive": "Glueball Spectra of SU(2) Gauge Theories in 3 and 4 Dimensions: A\n  Comparison with the Isgur-Paton Flux Tube Model: We use the results of recent lattice calculations to obtain (part of) the\nmass spectrum of continuum SU(2) gauge theory in both 2+1 and 3+1 dimensions.\nWe compare these spectra to the predictions of the Isgur-Paton flux tube model\nfor glueballs. We use this comparison to test the reliability of different\naspects of the model and also to learn which aspects of the lattice\ncalculations it is important to improve upon."
    },
    {
        "anchor": "Sphaleron rate from a modified Backus-Gilbert inversion method: We compute the sphaleron rate in quenched QCD for a temperature $T \\simeq\n1.24~T_c$ from the inversion of the Euclidean lattice time correlator of the\ntopological charge density. We explore and compare two different strategies:\none follows a new approach proposed in this study and consists in extracting\nthe rate from finite lattice spacing correlators, and then in taking the\ncontinuum limit at fixed smoothing radius followed by a zero-smoothing\nextrapolation; the other follows the traditional approach of extracting the\nrate after performing such double extrapolation directly on the correlator. In\nboth cases the rate is obtained from a recently-proposed modification of the\nstandard Backus-Gilbert procedure. The two strategies lead to compatible\nestimates within errors, which are then compared to previous results in the\nliterature at the same or similar temperatures; the new strategy permits to\nobtain improved results, in terms of statistical and systematic uncertainties.",
        "positive": "Canonical approach to the finite density QCD with winding number\n  expansion: The canonical partition function is related to the grand canonical one\nthrough the fugacity expansion and is known to have no sign problem. In this\npaper we perform the fugacity expansion by a method of the hopping parameter\nexpansion in temporal direction for the lattice QCD: winding number expansion.\nThe canonical partition function is constructed for Nf=2 QCD starting from\ngauge configurations at zero chemical potential. After derivation of the\ncanonical partition function we calculate hadronic observables like chiral\ncondensate and quark number density and the pressure at the real chemical\npotential."
    },
    {
        "anchor": "Exploration of sea quark effects in two-flavor QCD with the\n  O(a)-improved Wilson quark action: We explore sea quark effects in the light hadron mass spectrum in a\nsimulation of two-flavor QCD using the nonperturbatively O(a)-improved Wilson\nfermion action. In order to identify finite-size effects, light meson masses\nare measured on 12^3x48, 16^3x48 and 20^3x48 lattices with a~0.1 fm. On the\nlargest lattice, where the finite-size effect is negligible, we find a\nsignificant increase of the strange vector meson mass compared to the quenched\napproximation. We also investigate the quark mass dependence of pseudoscalar\nmeson masses and decay constants and test the consistency with (partially\nquenched) chiral perturbation theory.",
        "positive": "$\u03b8$ dependence in $SU(3)$ Yang-Mills theory from analytic\n  continuation: We investigate the topological properties of the $SU(3)$ pure gauge theory by\nperforming numerical simulations at imaginary values of the $\\theta$ parameter.\nBy monitoring the dependence of various cumulants of the topological charge\ndistribution on the imaginary part of $\\theta$ and exploiting analytic\ncontinuation, we determine the free energy density up to the sixth order order\nin $\\theta$, $f(\\theta,T) = f(0,T) + {1\\over 2} \\chi(T) \\theta^2 (1 + b_2(T)\n\\theta^2 + b_4(T) \\theta^4 + O(\\theta^6))$. That permits us to achieve\ndeterminations with improved accuracy, in particular for the higher order\nterms, with control over the continuum and the infinite volume extrapolations.\nWe obtain $b_2=-0.0216(15)$ and $|b_4|\\lesssim 4\\times 10^{-4}$."
    },
    {
        "anchor": "Resonance Scattering Phase Shifts on a Non-Rest Frame Lattice: Many low energy hadrons, such as the rho, can be observed as resonances in\nscattering experiments. A proposal by L\\\"uscher enables one to determine\ninfinite volume elastic scattering phases from the two-particle energy spectrum\nmeasured from finite periodic lattices. In this work, we generalize the\nformalism to the case where the total momentum of the particles is non-zero;\ni.e. the lattice frame is not the center-of-mass frame of the scattering\nparticles. There are several advantages to this procedure including making a\nwider variety of center of mass energies accessible with a fixed lattice\nvolume, and making the avoided level crossing in a P-wave decay occur with a\nsmaller volume. The formalism is tested with a simple lattice model of two\nfields with different masses and a 3-point coupling in 3+1 dimensions. We find\nremarkable agreement between the rest-frame and non-rest-frame scattering.",
        "positive": "Improvement of quark propagator estimation through domain decomposition: Applying domain decomposition to the lattice Dirac operator and the\nassociated quark propagator, we arrive at expressions which, with the proper\ninsertion of random sources therein, can provide improvement to the estimation\nof the propagator. Schemes are considered for both open and closed (or loop)\npropagators. In the end, our technique for improving open contributions is\nsimilar to the ``maximal variance reduction'' approach of Michael and Peisa,\nbut contains the advantage, especially for improved actions, of dealing\ndirectly with the Dirac operator. Using these improved open propagators for the\nChirally Improved operator, we present preliminary results for the static-light\nmeson spectrum."
    },
    {
        "anchor": "B^0_s and B^0 Mixing in the Standard Model and Beyond: A Progress Report: We give a progress report on the calculation of B meson mixing matrix\nelements, focusing on contributions that could arise beyond the Standard Model.\nThe calculation uses asqtad (light quark) and Fermilab (heavy quark) valence\nactions and MILC ensembles with 2+1 flavors of asqtad sea quarks. We report\npreliminary B^0_s fit results, at a lattice spacing of 0.12 fm, for the SUSY\nbasis of effective four-quark mixing operators and include an estimate for the\nfinal error budget.",
        "positive": "B -> pi l nu at three lattice spacings: The increasing accuracy of experimental results for the exclusive,\nsemileptonic decay B -> pi l nu requires a similarly accurate calculation of\nthe hadronic matrix elements, to determine |Vub|. We present preliminary\nresults for the form factors of the B to light meson decay mode. Using results\nfrom three lattices in the range 5.7 <= beta <= 6.1 we study the dependence on\nthe lattice spacing."
    },
    {
        "anchor": "Localised distributions in complex Langevin dynamics: Complex Langevin dynamics can be used to perform numerical simulations of\ntheories with a complex action. In order to justify the procedure, it is\nimportant to understand the properties of the real and positive distribution,\nwhich is effectively sampled during the stochastic process. In the context of a\nsimple model, we study this distribution and relate the results to the recently\nderived criteria for correctness. We demonstrate analytically that if the\ndistribution has support only on a strip in the complexified configuration\nspace, correct results are expected.",
        "positive": "Isolating the \u039b(1405) in Lattice QCD: The negative-parity ground state of the \\Lambda{} baryon lies surprisingly\nlow in mass. At 1405.1 MeV, it lies lower than the negative-parity ground state\nnucleon, even though it has a valence strange quark. Using the PACS-CS\n(2+1)-flavour full-QCD ensembles available through the ILDG, we employ a\nvariational analysis using source and sink smearing to isolate this elusive\nstate. We find three low-lying odd-parity states, and for the first time\nreproduce the correct level ordering with respect to the nearby scattering\nthresholds."
    },
    {
        "anchor": "Autocorrelation in Updating Pure SU(3) Lattice Gauge Theory by the use\n  of Overrelaxed Algorithms: We measure the sweep-to-sweep autocorrelations of blocked loops below and\nabove the deconfinement transition for SU(3) on a $16^4$ lattice using\n20000-140000 Monte-Carlo updating sweeps. A divergence of the autocorrelation\ntime toward the critical $\\beta$ is seen at high blocking levels. The peak is\nnear $\\beta$ = 6.33 where we observe 440 $\\pm$ 210 for the autocorrelation time\nof $1\\times 1$ Wilson loop on $2^4$ blocked lattice. The mixing of 7 Brown-Woch\noverrelaxation steps followed by one pseudo-heat-bath step appears optimal to\nreduce the autocorrelation time below the critical $\\beta$. Above the critical\n$\\beta$, however, no clear difference between these two algorithms can be seen\nand the system decorrelates rather fast.",
        "positive": "Entanglement entropy of SU(3) Yang-Mills theory: We calculate the entanglement entropy using a SU(3) quenched lattice gauge\nsimulation. We find that the entanglement entropy scales as $1/l^2$ at small\n$l$ as in the conformal field theory. Here $l$ is the size of the system, whose\ndegrees of freedom is left after the other part are traced out. The derivative\nof the entanglement entropy with respect to $l$ hits zero at about $l^{\\ast} =\n0.6 \\sim 0.7$ [fm] and vanishes above the length. It may imply that the\nYang-Mills theory has the mass gap of the order of $1/l^{\\ast}$. Within our\nstatistical errors, no discontinuous change can be seen in the entanglement\nentropy. We discuss also a subtle point appearing in gauge systems when we\ndivide a system with cuts."
    },
    {
        "anchor": "Non-perturbative Studies of Non-conformal Field Theories: Many of the exciting features of the Standard Model of the elementary\nparticles are inherently non-perturbative. A theoretical understanding of many\nphysics aspects beyond the Standard Model of elementary particles also requires\na non-perturbative framework. One such framework involves discretizing quantum\nfield theories on a spacetime lattice. We can use this lattice regularization\nmethod to study supersymmetric versions of physics beyond the Standard Model.\nIn this thesis, we discuss the spacetime lattice setup, and with the examples\nof different models, we will see the numerical capability of this tool in\nexploring field theory regimes that are not accessible through perturbation\ntheory. We use an efficient version of the Monte Carlo algorithm to update the\nfield configurations in the path integral and eventually reach the equilibrium\nconfigurations. A version of the gauge/gravity conjecture connects weakly\ncoupled gravitational theories to strongly coupled field theories. We will\nmainly focus on the non-conformal analogs of the conjecture in lower\ndimensions. This thesis mainly discusses the numerical simulation results of\ntwo lower-dimensional models. One is the bosonic version of the BMN matrix\nquantum mechanics and the other is a two-dimensional Yang-Mills theory\ncontaining four supersymmetries. Our numerical results suggest that the phase\ndiagram of bosonic BMN model smoothly interpolates between the bosonic BFSS and\nthe gauged Gaussian model, with first-order deconfinement phase transition at\nall couplings. Our simulation results for two-dimensional Yang-Mills theory\nthat contains four supersymmetries show that this model admits a deconfinement\nphase transition in the limit of a large number of colors. We also show that\nthe nature of the transition looks similar to its maximally supersymmetric\ncousin in the weak coupling regime.",
        "positive": "The path from lattice QCD to the short-distance contribution to\n  $0\u03bd\u03b2\u03b2$ decay with a light Majorana neutrino: Neutrinoless double-$\\beta$ ($0\\nu\\beta\\beta$) decay of certain atomic\nisotopes, if observed, will have significant implications for physics of\nneutrinos and models of physics beyond the Standard Model. In the simplest\nscenario, if the mass of the light neutrino of the Standard Model has a\nMajorana component, it can mediate the decay. Systematic theoretical studies of\nthe decay rate in this scenario, through effective field theories matched to\n\\emph{ab initio} nuclear many-body calculations, are needed to draw conclusions\nabout the hierarchy of neutrino masses, and to plan the design of future\nexperiments. However, a recently identified short-distance contribution at\nleading order in the effective field theory amplitude of the subprocess $nn \\to\npp\\,(ee)$ remains unknown, and only lattice quantum chromodynamics (QCD) can\ndirectly and reliably determine the associated low-energy constant. While the\nnumerical computations of the correlation function for this process are\nunderway with lattice QCD, the connection to the physical amplitude, and hence\nthis short-distance contribution, is missing. A complete framework that enables\nthis complex matching is developed in this paper. The complications arising\nfrom Euclidean and finite-volume nature of the corresponding correlation\nfunction are fully resolved, and the value of the formalism is demonstrated\nthrough a simple example. The result of this work, therefore, fills the gap\nbetween first-principle studies of the $nn \\to pp\\,(ee)$ amplitude from lattice\nQCD and those from effective field theory, and can be readily employed in the\nongoing lattice-QCD studies of this process."
    },
    {
        "anchor": "String Representation of the Abelian Higgs Theory and Aharonov-Bohm\n  Effect on the Lattice: The partition function of the $4D$ lattice Abelian Higgs theory is\nrepresented as the sum over world sheets of Nielsen--Olesen strings. The\ncreation and annihilation operators of the strings are constructed. The\ntopological long--range interaction of the strings and charged particles is\nshown to exist; it is proportional to the linking number of the string world\nsheet and particle world trajectory.",
        "positive": "Supersymmetric quantum mechanics on the lattice: I. Loop formulation: Simulations of supersymmetric field theories on the lattice with\n(spontaneously) broken supersymmetry suffer from a fermion sign problem related\nto the vanishing of the Witten index. We propose a novel approach which solves\nthis problem in low dimensions by formulating the path integral on the lattice\nin terms of fermion loops. For N = 2 supersymmetric quantum mechanics the loop\nformulation becomes particularly simple and in this paper - the first in a\nseries of three - we discuss in detail the reformulation of this model in terms\nof fermionic and bosonic bonds for various lattice discretisations including\none which is Q-exact."
    },
    {
        "anchor": "Tests of Hypercubic Fermion Actions: I have performed scaling tests using quenched spectroscopy of a family of\nfermion actions which have a hypercubic kinetic term, gauge connections built\nof smeared links, and an anomalous magnetic moment term. These actions show\nimproved rotational invariance compared to the standard Wilson action and to\nthe tadpole-improved clover action. Hyperfine splittings are improved compared\nto the standard Wilson action (at the level of a factor of three in the lattice\nspacing), and are about the same as for the tadpole-improved clover action.",
        "positive": "The Schwinger Model with Perfect Staggered Fermions: We construct and test a quasi-perfect lattice action for staggered fermions.\nThe construction starts from free fermions, where we suggest a new blocking\nscheme, which leads to excellent locality of the perfect action. An adequate\ntruncation preserves a high quality of the free action. An Abelian gauge field\nis inserted in d=2 by effectively tuning the couplings to a few short-ranged\nlattice paths, based on the behavior of topological zero modes. We simulate the\nSchwinger model with this action, applying a new variant of Hybrid Monte Carlo,\nwhich damps the computational overhead due to the non-standard couplings. We\nobtain a tiny ``pion'' mass down to very small \\beta, while the ``\\eta'' mass\nfollows very closely the prediction of asymptotic scaling. The observation that\neven short-ranged quasi-perfect actions can yield strong improvement is most\nrelevant in view of QCD."
    },
    {
        "anchor": "Light quark correlators in a mixed-action setup: We report our progress in simulating Neuberger valence fermions on N_f=2\nWilson O(a)-improved sea quarks. We compute correlators with valence quark\nmasses both in the p- and in the epsilon-regime, and we match the results with\nthe predictions of the Chiral Effective Theory in the mixed regime. This allows\nus to extract the Low Energy Couplings (LECs) of the N_f=2 theory and to test\nthe validity of the approach.",
        "positive": "Including heavy spin effects in a lattice QCD study of\n  static-static-light-light tetraquarks: In previous works we predicted the existence of a $\\bar b \\bar b u d$\ntetraquark with quantum numbers $I(J^P) = 0(1^+)$ using the static\napproximation for the $\\bar b$ quarks and neglecting heavy spin effects. Since\nthe binding energy is of the same order as expected for these heavy spin\neffects, it is essential to include them in the computation. Here we present a\ncorresponding method and show evidence that binding is only slightly weakened\nand that the $\\bar b \\bar b u d$ tetraquark persists."
    },
    {
        "anchor": "A class of chiral fermion models: We study the relation between the Roma and Zaragoza proposals for chiral\nfermions on the lattice. The fermion action in the Roma approach is shown to be\nequivalent to one of the Zaragoza type. This result is used to perform a\nmean-field study of the phase diagram for chiral Yukawa models based on the\nRoma action. The phase diagram is compared with the one based on the Zaragoza\nmodel with the most local choice for the fermion interactions.",
        "positive": "Heavy baryon mass spectrum from lattice QCD with 2+1 dynamical sea quark\n  flavors: We investigate the mass differences of charm and bottom heavy baryons, using\nMILC lattice gauge configurations with 2+1 dynamical sea quark flavors. We\nextend our previous work to three lattice spacings: fine (a~0.09), coarse\n(a~0.12), and medium-coarse (a~0.15) ensembles. For extrapolations and\ninterpolations, we apply simultaneous quadratic fits and simple linear fits\nwith the full QCD data points for the valence quark masses as well as the sea\nquark masses."
    },
    {
        "anchor": "Chiral symmetry breaking and the Banks--Casher relation in lattice QCD\n  with Wilson quarks: The Banks--Casher relation links the spontaneous breaking of chiral symmetry\nin QCD to the presence of a non-zero density of quark modes at the low end of\nthe spectrum of the Dirac operator. Spectral observables like the number of\nmodes in a given energy interval are renormalizable and can therefore be\ncomputed using the Wilson formulation of lattice QCD even though the latter\nviolates chiral symmetry at energies on the order of the inverse lattice\nspacing. Using numerical simulations, we find (in two-flavour QCD) that the low\nquark modes do condense in the expected way. In particular, the chiral\ncondensate can be accurately calculated simply by counting the low modes on\nlarge lattices. Other spectral observables can be considered as well and have a\npotentially wide range of uses.",
        "positive": "Semileptonic $B$-meson decays to light pseudoscalar mesons on the HISQ\n  ensembles: We report the status of an ongoing lattice-QCD calculation of form factors\nfor exclusive semileptonic decays of $B$ mesons with both charged currents\n($B\\to\\pi\\ell\\nu$, $B_s\\to K\\ell\\nu$) and neutral currents\n($B\\to\\pi\\ell^+\\ell^-$, $B\\to K\\ell^+\\ell^-$). The results are important for\nconstraining or revealing physics beyond the Standard Model. This work uses\nMILC's (2+1+1)-flavor ensembles with the HISQ action for the sea and light\nvalence quarks and the clover action in the Fermilab interpretation for the $b$\nquark. Simulations are carried out at three lattice spacings down to $0.088$\nfm, with both physical and unphysical sea-quark masses. We present preliminary\nresults for correlation-function fits."
    },
    {
        "anchor": "Trajectory Length and Autocorrelation Times -- Nf=2 simulations in the\n  Schroedinger functional: A status report is presented on the large-volume simulations in the\nSchroedinger functional with two flavours of O(a) improved Wilson quarks\nperformed by the ALPHA collaboration. The physics goal is to set the scale for\nthe computation of the fundamental parameters of QCD. In this talk the emphasis\nis on aspects of the Hybrid Monte-Carlo algorithm, which we use with\n(symmetric) even-odd and Hasenbusch preconditioning. We study the dependence of\naucorrelation times on the trajectory length. The latter is found to be\nsignificant for fermionic correlators, the trajectories longer than unity\nperforming better than the shorter ones.",
        "positive": "Order of the Chiral and Continuum Limits in Staggered Chiral\n  Perturbation Theory: Durr and Hoelbling recently observed that the continuum and chiral limits do\nnot commute in the two dimensional, one flavor, Schwinger model with staggered\nfermions. I point out that such lack of commutativity can also be seen in\nfour-dimensional staggered chiral perturbation theory (SChPT) in quenched or\npartially quenched quantities constructed to be particularly sensitive to the\nchiral limit. Although the physics involved in the SChPT examples is quite\ndifferent from that in the Schwinger model, neither singularity seems to be\nconnected to the trick of taking the nth root of the fermion determinant to\nremove unwanted degrees of freedom (\"tastes\"). Further, I argue that the\nsingularities in SChPT are absent in most commonly-computed quantities in the\nunquenched (full) QCD case and do not imply any unexpected systematic errors in\nrecent MILC calculations with staggered fermions."
    },
    {
        "anchor": "A Preconditioner for Improved Fermion Actions: SSOR preconditioning of fermion matrix inversions which is parallelized using\na locally-lexicographic lattice sub-division, has been shown to be very\nefficient for standard Wilson fermions. We demonstrate here the power of this\nmethod for the Sheikholeslami-Wohlert improved fermion action and for a\nrenormalization group improved action incorporating couplings of the lattice\nfermion fields up to the diagonal in the unit hypercube.",
        "positive": "Computing K and D meson masses with N_f = 2+1+1 twisted mass lattice QCD: We discuss the computation of the mass of the K and D mesons within the\nframework of N_f = 2+1+1 twisted mass lattice QCD from a technical point of\nview. These quantities are essential, already at the level of generating gauge\nconfigurations, being obvious candidates to tune the strange and charm quark\nmasses to their physical values. In particular, we address the problems related\nto the twisted mass flavor and parity symmetry breaking, which arise when\nconsidering a non-degenerate (c,s) doublet. We propose and verify the\nconsistency of three methods to extract the K and D meson masses in this\nframework."
    },
    {
        "anchor": "Measuring an entropy in heavy ion collisions: We propose to use the coincidence method of Ma to measure an entropy of the\nsystem created in heavy ion collisions. Moreover we estimate, in a simple\nmodel, the values of parameters for which the thermodynamical behaviour sets\nin.",
        "positive": "Towards the determination of the gluon helicity distribution in the\n  nucleon from lattice quantum chromodynamics: We present the first exploratory lattice quantum chromodynamics (QCD)\ncalculation of the polarized gluon Ioffe-time pseudo-distribution in the\nnucleon. The Ioffe-time pseudo-distribution provides a frame-independent and\ngauge-invariant framework to determine the gluon helicity in the nucleon from\nfirst principles. We employ a high-statistics computation using a $32^3\\times\n64$ lattice ensemble characterized by a $358$ MeV pion mass and a $0.094$ fm\nlattice spacing. We establish the pseudo-distribution approach as a feasible\nmethod to address the proton spin puzzle with successive improvements in\nstatistical and systematic uncertainties anticipated in the future. Within the\nstatistical precision of our data, we find a good comparison between the\nlattice determined polarized gluon Ioffe-time distribution and the\ncorresponding expectations from the state-of-the-art global analyses. We find a\nhint for a nonzero gluon spin contribution to the proton spin from the\nmodel-independent extraction of the gluon helicity pseudo-distribution over a\nrange of Ioffe-time, $\\nu\\lesssim 9$."
    },
    {
        "anchor": "Analyticity in theta on the lattice and the large volume limit of the\n  topological susceptibility: Non-analyticity of QCD with a \\theta term at \\theta=0 may signal a\nspontaneous breaking of both parity and time reversal invariance. We address\nthis issue by investigating the large volume limit of the topological\nsusceptibility $\\chi$ in pure SU(3) gauge theory. We obtain an upper bound for\nthe symmetry breaking order parameter <Q> and, as a byproduct, the value\n\\chi=(173.4(+/- 0.5)(+/- 1.2)(+1.1 / -0.2) MeV)^4 at \\beta=6 (a approx= 0.1\nfermi). The errors are the statistical error from our data, the one derived\nfrom the value used for \\Lambda_L and an estimate of the systematic error\nrespectively.",
        "positive": "$H(4)$ tensor representations for the lattice Landau gauge gluon\n  propagator and the estimation of lattice artefacts: The use of lattice tensor representations is explored to investigate the\nlattice Landau gauge gluon propagator for the pure SU(3) Yang-Mills gauge\ntheory in 4D. The analysis of several tensor bases allows to quantify the\ncompleteness of the various tensor bases considered, the deviations of the\nlattice results from the continuum theory due to the lattice artefacts and\nestimate the theoretical uncertainty in the propagator. Furthermore, our\nanalysis tests continuum based relations with the lattice data and show that\nthe lattice Landau gauge gluon propagator is described by a unique form factor,\nas in the continuum formulation."
    },
    {
        "anchor": "Gluons at finite temperature: The gluon propagator is investigated at finite temperature via lattice\nsimulations. In particular, we discuss its interpretation as a massive-type\nbosonic propagator. Moreover, we compute the corresponding spectral density and\nstudy the violation of spectral positivity. Finally, we explore the dependence\nof the gluon propagator on the phase of the Polyakov loop.",
        "positive": "A Random Matrix Study of the QCD Sign Problem: We investigate the severity of the sign problem in a random matrix model for\nQCD at finite temperature T and baryon chemical potential mu. We obtain\nanalytic expression for the average phase factor -- the measure of the severity\nof the sign problem at arbitrary T and mu. We observe that the sign problem\nbecomes less severe as the temperature is increased. We also find the domain\nwhere the sign problem is maximal -- the average phase factor is zero, which is\nrelated to the pion condensation phase in the QCD with finite isospin chemical\npotential. We find that, in the matrix model we studied, the critical point is\nlocated inside the domain of the maximal sign problem, making the point\ninaccessible to conventional reweighting techniques. We observe and describe\nthe scaling behavior of the size and shape of the pion condensation near the\nchiral limit."
    },
    {
        "anchor": "How far can you go ? Surprises and pitfalls in three-flavour chiral\n  extrapolations: The presence of strange sea quark pairs may have a significant impact of the\npattern of chiral symmetry breaking : in particular large differences can occur\nbetween the chiral limits of two and three massless flavours (i.e., whether\n$m_s$ is kept at its physical value or sent to zero). We recall some\nindications of such a scenario in QCD, in relation with the peculiar dynamics\nof the scalar sector. We explain how this could affect the convergence of\nthree-flavour chiral series, commonly used to extrapolate the results of\nlattice simulations. Finally, we indicate how lattice simulations with three\ndynamical flavours could unveil such an effect through the quark-mass\ndependence of light meson masses and decay constants.",
        "positive": "Analytic continuation from imaginary to real chemical potential in\n  two-color QCD: The method of analytic continuation from imaginary to real chemical potential\nis one of the most powerful tools to circumvent the sign problem in lattice\nQCD. Here we test this method in a theory, 2-color QCD, which is free from the\nsign problem. We find that the method gives reliable results, within\nappropriate ranges of the chemical potential, and that a considerable\nimprovement can be achieved if suitable functions are used to interpolate data\nwith imaginary chemical potential."
    },
    {
        "anchor": "Interplay of universality classes in a three-dimensional Yukawa model: We investigate numerically on the lattice the interplay of universality\nclasses of the three-dimensional Yukawa model with U(1) chiral symmetry, using\nthe Binder method of finite size scaling. At zero Yukawa coupling the scaling\nrelated to the magnetic Wilson--Fisher fixed point is confirmed. At\nsufficiently strong Yukawa coupling the dominance of the chiral fixed point\nassociated with the 3D Gross--Neveu model is observed for various values of the\ncoupling parameters, including infinite scalar selfcoupling. In both cases the\nBinder method works consistently in a broad range of lattice sizes. However,\nwhen the Yukawa coupling is decreased the finite size behavior gets complicated\nand the Binder method gives inconsistent results for different lattice sizes.\nThis signals a cross-over between the universality classes of the two fixed\npoints.",
        "positive": "A new scheme for color confinement due to violation of the non-Abelian\n  Bianchi identities: A new scheme for color confinement in QCD due to violation of the non-Abelian\nBianchi identities is discussed. The violation of the non-Abelian Bianchi\nidentities (VNABI) $J_{\\mu}$ is equal to Abelian-like monopole currents\n$k_{\\mu}$ defined by the violation of the Abelian-like Bianchi identities.\nAlthough VNABI is an adjoint operator satisfying the covariant conservation\nrule $D_{\\mu}J_{\\mu}=0$, it gives us, at the same time, the Abelian-like\nconservation rule $\\partial_{\\mu}J_{\\mu}=0$. The Abelian-like conservation rule\n$\\partial_{\\mu}J_{\\mu}=0$ is also gauge-covariant. There are $N^2-1$ conserved\nmagnetic charges in the case of color $SU(N)$. The charge of each component of\nVNABI is quantized \\`{a} la Dirac. VNABI satisfying the Dirac quantization\ncondition could be defined on lattice as lattice Abelian-like monopole currents\nwithout any gauge-fixing. Previous studies of the Abelian-like monopoles\n$k_{\\mu}$ on lattice show that non-Abelian color confinement could be\nunderstood by the Abelian-like dual Meissner effect due to condensation of\nVNABI."
    },
    {
        "anchor": "Isovector parton distribution functions of the proton on a superfine\n  lattice: We study isovector unpolarized and helicity parton distribution functions\n(PDF) of the proton within the framework of Large Momentum Effective Theory. We\nuse a gauge ensemble, generated by the MILC Collaboration, with a superfine\nlattice spacing of $0.042$ fm and a pion mass of $310$ MeV, enabling us to\nsimultaneously reach sub-fermi spatial separations and larger nucleon momenta.\nWe compare the spatial dependence of quasi-PDF matrix elements in different\nrenormalization schemes with the corresponding results of the global fits,\nobtained using 1-loop perturbative matching. We present determinations of the\nfirst four moments of the unpolarized and helicity PDFs of proton from the\nIoffe-time dependence of the isovector matrix elements, obtained by employing a\nratio-based renormalization scheme.",
        "positive": "Glueballs and topology with O(a)-improved lattice QCD: We present evidence for unquenching effects in N_f=2, 16^3 32 ensembles by\ncomparing with `equivalent' quenched data at r_0~5.0. A (small) VEV for\ntorelons signals (weak) string breaking. A 15-20 % reduction in the scalar\nglueball mass relative to quenched is argued to be (in part at least) a\ndiscretisation effect. We find a chiral suppression of the topological\nsusceptibility consistent with expectations, and agreement between fermionic\nand gluonic methods for measuring the topological charge."
    },
    {
        "anchor": "Intrinsic quark transverse momentum in the nucleon from lattice QCD: A better understanding of transverse momentum (k_T-) dependent quark\ndistributions in a hadron is needed to interpret several experimentally\nobserved large angular asymmetries and to clarify the fundamental role of gauge\nlinks in non-abelian gauge theories. Based on manifestly non-local gauge\ninvariant quark operators we introduce process-independent k_T-distributions\nand study their properties in lattice QCD. We find that the longitudinal and\ntransverse momentum dependence approximately factorizes, in contrast to the\nbehavior of generalized parton distributions. The resulting quark\nk_T-probability densities for the nucleon show characteristic dipole\ndeformations due to correlations between intrinsic k_T and the quark or nucleon\nspin. Our lattice calculations are based on N_f=2+1 mixed action propagators of\nthe LHP collaboration.",
        "positive": "Matching the High Momentum Modes in a Truncated Determinant Algorithm: Within a truncated determinant algorithm, two alternatives are discussed for\nincluding systematically the remaining ultraviolet modes. Evidence is presented\nthat these modes are accurately described by an effective action involving only\nsmall Wilson loops."
    },
    {
        "anchor": "Exploring the pi+ pi+ interaction in lattice QCD: An effective residual interaction for a meson-meson system is computed in\nlattice QCD. We describe the theoretical framework and present its application\nto the I=2 channel S-wave interaction of the pi pi system. Scattering phase\nshifts are also computed and compared to experimental results.",
        "positive": "Continuum-extrapolated NNLO Valence PDF of Pion at the Physical Point: We present lattice QCD calculations of valence parton distribution function\n(PDF) of pion employing next-to-next-leading-order (NNLO) perturbative QCD\nmatching. Our calculations are based on three gauge ensembles of 2+1 flavor\nhighly improved staggered quarks and Wilson--Clover valance quarks,\ncorresponding to pion mass $m_\\pi=140$~MeV at a lattice spacing $a=0.076$~fm\nand $m_\\pi=300$~MeV at $a=0.04, 0.06$~fm. This enables us to present, for the\nfirst time, continuum-extrapolated lattice QCD results for NNLO valence PDF of\nthe pion at the physical point. Applying leading-twist expansion for\nrenormalization group invariant (RGI) ratios of bi-local pion matrix elements\nwith NNLO Wilson coefficients we extract $2^{\\mathrm{nd}}$, $4^{\\mathrm{th}}$\nand $6^{\\mathrm{th}}$ Mellin moments of the PDF. We reconstruct the Bjorken-$x$\ndependence of the NNLO PDF from real-space RGI ratios using a deep neural\nnetwork (DNN) as well as from momentum-space matrix elements renormalized using\na hybrid-scheme. All our results are in broad agreement with the results of\nglobal fits to the experimental data carried out by the xFitter and JAM\ncollaborations."
    },
    {
        "anchor": "Glueball relevant study on isoscalars from $N_f=2$ lattice QCD: We perform a glueball-relevant study on isoscalars based on anisotropic\n$N_f=2$ lattice QCD gauge configurations. In the scalar channel, we identify\nthe ground state obtained through gluonic operators to be a single-particle\nstate through its dispersion relation. When $q\\bar{q}$ operator is included, we\nfind the mass of this state does not change, and the $q\\bar{q}$ operator\ncouples very weakly to this state. So this state is most likely a glueball\nstate. For pseudoscalars, along with the exiting lattice results, our study\nimplies that both the conventional $q\\bar{q}$ state $\\eta_2$ (or $\\eta'$ in\nflavor $SU(3)$) and a heavier glueball-like state with a mass of roughly 2.6\nGeV exist in the spectrum of lattice QCD with dynamical quarks.",
        "positive": "Heavy baryon mass spectrum from lattice QCD with 2+1 flavors: We study the heavy baryon mass spectrum on gauge configurations that include\n2+1 flavors of dynamical improved staggered quarks. A valence clover heavy\nquark is combined with two improved staggered light quark propagators to form\nbaryons with different flavors. We are using MILC coarse gauge configurations\nwith a lattice spacing of about 0.12 fm. In this preliminary investigation, we\nexplore the chiral limit by studying two light sea quark masses, three\ndifferent strange valence quark masses, and nine different light valence quark\nmasses ranging from 0.1 to 0.4 times the nominal strange quark mass."
    },
    {
        "anchor": "First moments of the nucleon transverse quark spin densities using\n  lattice QCD: We present a calculation of the Mellin moments of the transverse quark spin\ndensities in the nucleon using lattice QCD. The densities are extracted from\nthe unpolarized and transversity generalized form factors extrapolated to the\ncontinuum limit using three $N_f=2+1+1$ twisted mass fermion gauge ensembles\nsimulated with physical quark masses and spanning three lattice spacings. The\nfirst moment of transversely polarized quarks in an unpolarized nucleon shows\nan interesting distortion, which can be traced back to the sharp falloff of the\ntransversity generalized form factor $\\bar{B}_{Tn0}(t)$. The isovector tensor\nanomalous magnetic moment is determined to be $\\kappa_T=1.051(94)$, which\nconfirms a negative and large Boer-Mulders function, $h_1^{\\perp}$, in the\nnucleon.",
        "positive": "Non-Commutativity of the Zero Chemical Potential Limit and the\n  Thermodynamic Limit in Finite Density Systems: Monte Carlo simulations of finite density systems are often plagued by the\ncomplex action problem. We point out that there exists certain\nnon-commutativity in the zero chemical potential limit and the thermodynamic\nlimit when one tries to study such systems by reweighting techniques. This is\ndemonstrated by explicit calculations in a Random Matrix Theory, which is\nthought to be a simple qualitative model for finite density QCD. The\nfactorization method allows us to understand how the non-commutativity, which\nappears at the intermediate steps, cancels in the end results for physical\nobservables."
    },
    {
        "anchor": "Evidence of BRST-Symmetry Breaking in Lattice Minimal Landau Gauge: By evaluating the so-called Bose-ghost propagator, we present the first\nnumerical evidence of BRST-symmetry breaking for Yang-Mills theory in minimal\nLandau gauge, i.e. due to the restriction of the functional integration to the\nfirst Gribov region in the Gribov-Zwanziger approach. Our data are well\ndescribed by a simple fitting function, which can be related to a massive gluon\npropagator in combination with an infrared-free (Faddeev-Popov) ghost\npropagator. As a consequence, the Bose-ghost propagator, which has been\nproposed as a carrier of the confining force in minimal Landau gauge, displays\na 1/p^4 singularity in the infrared limit.",
        "positive": "Collins-Soper Kernel for TMD Evolution from Lattice QCD: The Collins-Soper kernel relates transverse momentum-dependent parton\ndistribution functions (TMDPDFs) at different energy scales. For small parton\ntransverse momentum $q_T\\sim \\Lambda_\\text{QCD}$, this kernel is\nnon-perturbative and can only be determined with controlled uncertainties\nthrough experiment or first-principles calculations. This work presents the\nfirst exploratory determination of the Collins-Soper kernel using the lattice\nformulation of Quantum Chromodynamics. In a quenched calculation, the $N_f=0$\nkernel is determined at scales in the range 250 MeV $< q_T < 2$ GeV, and an\nanalysis of the remaining systematic uncertainties is undertaken."
    },
    {
        "anchor": "Global symmetry breaking in gauge theories: the case of multiflavor\n  scalar chromodynamics: Universal features of continuous phase transitions can be investigated by\nstudying the $\\phi^4$ field theory with the corresponding global symmetry\nbreaking pattern. When gauge symmetries are present, the same technique is\nusually applied to a gauge-invariant order parameter field, as in the\nPisarski-Wilczek analysis of the QCD chiral phase transition. Gauge fields are\nthus assumed to be irrelevant in the effective critical model, a fact that is\nhowever far from trivial. We will investigate the validity of this approach\nusing three-dimensional scalar lattice models with non-abelian global and local\nsymmetries, for which critical exponents and scaling functions can be\nnumerically determined with high accuracy.",
        "positive": "Center vortex model for the infrared sector of Yang-Mills theory -\n  Quenched Dirac spectrum and chiral condensate: The Dirac operator describing the coupling of continuum quark fields to SU(2)\ncenter vortex world-surfaces composed of elementary squares on a hypercubic\nlattice is constructed. It is used to evaluate the quenched Dirac spectral\ndensity in the random vortex world-surface model, which previously has been\nshown to quantitatively reproduce both the confinement properties and the\ntopological susceptibility of SU(2) Yang-Mills theory. Under certain conditions\non the modeling of the vortex gauge field, a behavior of the quenched chiral\ncondensate as a function of temperature is obtained which is consistent with\nmeasurements in SU(2) lattice Yang-Mills theory."
    },
    {
        "anchor": "Topological susceptibility in two-flavor QCD: We compute the topological susceptibility in QCD with two flavors of\ndynamical fermions using numerical simulation with overlap fermions.",
        "positive": "Electromagnetic corrections to the hadronic vacuum polarization of the\n  photon within QED$_{\\rm L}$ and QED$_{\\rm M}$: We compute the leading QED corrections to the hadronic vacuum polarization\n(HVP) of the photon, relevant for the determination of leptonic anomalous\nmagnetic moments, $a_\\ell$. We work in the electroquenched approximation and\nuse dynamical QCD configurations generated by the CLS initiative with two\ndegenerate flavors of non-perturbatively O($a$)-improved Wilson fermions. We\nconsider QED$_{\\rm L}$ and QED$_{\\rm M}$ to deal with the finite-volume zero\nmodes. We compare results for the Wilson loops with exact analytical\ndeterminations. In addition we make sure that the volumes and photon masses\nused in QED$_{\\rm M}$ are such that the correct dispersion relation is\nreproduced by the energy levels extracted from the charged pions two-point\nfunctions. Finally we compare results for pion masses and the HVP between\nQED$_{\\rm L}$ and QED$_{\\rm M}$. For the vacuum polarization, corrections with\nrespect to the pure QCD case, at fixed pion masses, turn out to be at the\npercent level."
    },
    {
        "anchor": "Flavored tetraquark spectroscopy: The recent confirmation of the charged charmonium like resonance Z(4430) by\nthe LHCb experiment strongly suggests the existence of QCD multi quarks bound\nstates. Some preliminary results about hypothetical flavored tetraquark mesons\nare reported. Such states are particularly amenable to Lattice QCD studies as\ntheir interpolating operators do not overlap with those of ordinary\nhidden-charm mesons.",
        "positive": "Strange and charm meson masses from twisted mass lattice QCD: We present first results of a 2+1+1 flavor twisted mass lattice QCD\ncomputation of strange and charm meson masses. We focus on D and D_s mesons\nwith spin J = 0,1 and parity P = -,+."
    },
    {
        "anchor": "Physical-Continuum Limit of the Nucleon Gluon Parton Distribution from\n  Lattice QCD: We present the key results from the first study of the $x$-dependent nucleon\ngluon distribution from lattice QCD extrapolated to the physical-continuum\nlimit. We use ensembles with $2+1+1$ flavors of highly improved staggered\nquarks (HISQ) generated by the MILC Collaboration with clover fermions for the\nvalence action on three different lattice spacings and three different pion\nmasses. We took up to $O(10^6)$ measurements of two-point correlators,\nobtaining good signal at boost momenta up to 3~GeV. We extrapolated the reduced\npseudo-ITD matrix elements to the physical-continuum limit before extracting\n$xg(x)/\\langle x \\rangle_g$. Then using the gluon momentum fraction $\\langle x\n\\rangle_g$ calculated on the same configurations, we determine the unpolarized\nnucleon gluon PDF $xg(x)$ and compare results with other lattice and selected\nglobal fits.",
        "positive": "$DK/D\u03c0$ scattering and an exotic virtual bound state at the $SU(3)$\n  flavour symmetric point from lattice QCD: Elastic $S-$wave scattering of a charm meson with a light pseudoscalar meson\nin $J^P =0^+$ is investigated in the flavour $\\bar{\\mathbf{3}}$, $\\mathbf{6}$\nand $\\overline{\\mathbf{15}}$ sectors at the $SU(3)_f$ flavour point using\nlattice QCD, working on three volumes with $m_{\\pi} \\approx 700$ MeV. Large\nbases of interpolating operators are employed to extract finite-volume spectra,\nwhich are subsequently used with the L\\\"uscher method to provide constraints on\ninfinite-volume scattering amplitudes. Examining the singularities of the\namplitudes, the $S-$wave amplitude in the flavour $\\bar{\\mathbf{3}}$ sector is\nfound to contain a deeply bound state, strongly coupled to elastic threshold,\ncorresponding to the $J^P = 0^+$ $D_{s0}^*(2317)$. In the exotic flavour\n$\\mathbf{6}$ sector a virtual bound state is found at $\\sqrt{s_{\\rm{pole}}} =\n2510 - 2610$ MeV, roughly $40-140$ MeV below threshold, whereas the\n$\\overline{\\mathbf{15}}$ channel shows weak repulsion."
    },
    {
        "anchor": "Lattice-fermionic Casimir effect and topological insulators: The Casimir effect arises from the zero-point energy of particles in momentum\nspace deformed by the existence of two parallel plates. For degrees of freedom\non the lattice, its energy-momentum dispersion is determined so as to keep a\nperiodicity within the Brillouin zone, so that its Casimir effect is modified.\nWe study the properties of Casimir effect for lattice fermions, such as the\nnaive fermion, Wilson fermion, and overlap fermion based on the M\\\"obius\ndomain-wall fermion formulation, in the $1+1$-, $2+1$-, and $3+1$-dimensional\nspace-time with the periodic or antiperiodic boundary condition. An oscillatory\nbehavior of Casimir energy between odd and even lattice size is induced by the\ncontribution of ultraviolet-momentum (doubler) modes, which realizes in the\nnaive fermion, Wilson fermion in a negative mass, and overlap fermions with a\nlarge domain-wall height. Our findings can be experimentally observed in\ncondensed matter systems such as topological insulators and also numerically\nmeasured in lattice simulations.",
        "positive": "Beyond complex Langevin equations: A simple integral relation between a complex weight and the corresponding\npositive distribution is derived by introducing a second complex variable.\nTogether with the positivity and normalizability conditions, this sum rule\nallows to construct explicitly equivalent pairs of distributions in simple\ncases. In particular the well known solution for a complex gaussian\ndistribution is generalized to an arbitrary complex slope. This opens a\npossibility of positive representation of Feynman path integrals directly in\nthe Minkowski time. Such construction is then explicitly carried through in the\nsecond part of this presentation. The continuum limit of the new representation\nexists only if some of the additional couplings tend to infinity and are tuned\nin a specific way. The approach is then successfully applied to three quantum\nmechanical examples including a particle in a constant magnetic field -- a\nsimplest prototype of a Wilson line. Further generalizations are shortly\ndiscussed and an amusing interpretation of new variables is briefly mentioned."
    },
    {
        "anchor": "Anderson localization in QCD-like theories: We review the present status of the Anderson transition in the spectrum of\nthe Dirac operator of QCD-like theories on the lattice. Localized modes at the\nlow-end of the spectrum have been found in SU(2) Yang-Mills theory with overlap\nand staggered valence fermions as well as in Nf=2+1 QCD with staggered quarks.\nWe draw an analogy between the transition from localized to delocalized modes\nin the Dirac spectrum and the Anderson transition in electronic systems. The\nQCD transition turns out to be in the same universality class as the transition\nin the corresponding Anderson model. We also speculate on the possible physical\nrelevance of this transition to QCD at high temperature and the possible finite\ntemperature phase transition in QCD-like models with different fermion\ncontents.",
        "positive": "Current status of Dynamical Overlap project: We discuss the adaptation of the Hybrid Monte Carlo algorithm to overlap\nfermions. We derive a method which can be used to account for the delta\nfunction in the fermionic force caused by the differential of the sign\nfunction. We discuss the algoritmic difficulties that have been overcome, and\nmention those that still need to be solved."
    },
    {
        "anchor": "Effects of Quenching and Partial Quenching on Penguin Matrix Elements: In the calculation of non-leptonic weak decay rates, a \"mismatch\" arises when\nthe QCD evolution of the relevant weak hamiltonian down to hadronic scales is\nperformed in unquenched QCD, but the hadronic matrix elements are then computed\nin (partially) quenched lattice QCD. This mismatch arises because the\ntransformation properties of penguin operators under chiral symmetry change in\nthe transition from unquenched to (partially) quenched QCD. Here we discuss\nQCD-penguin contributions to $\\Delta S=1$ matrix elements, and show that new\nlow-energy constants contribute at leading order in chiral perturbation theory\nin this case. In the partially quenched case (in which sea quarks are present),\nthese low-energy constants are related to electro-magnetic penguins, while in\nthe quenched case (with no sea quarks) no such relation exists. As a simple\nexample, we give explicit results for $K^+\\to\\pi^+$ and $K^0\\to vacuum$ matrix\nelements, and discuss the implications for lattice determinations of\n$K\\to\\pi\\pi$ amplitudes from these matrix elements.",
        "positive": "Topology via Spectral Projectors with Staggered Fermions: The spectral projectors method is a way to obtain a theoretically well posed\ndefinition of the topological susceptibility on the lattice. Up to now this\nmethod has been defined and applied only to Wilson fermions. The goal of this\nwork is to extend the method to staggered fermions, giving a definition for the\nstaggered topological susceptibility and testing it in the pure $SU(3)$ gauge\ntheory. Besides, we also generalize the method to higher-order cumulants of the\ntopological charge distribution."
    },
    {
        "anchor": "An illustration of chiral fermions on a 1+1 dimensional lattice: The vectorlike doubling of low-energy excitations is in fact a natural\nconsequence of the pair-production around the zero-energy (E=0) due to the\nquantum field fluctuations of the lattice regularized vacuum. On the 1+1\ndimensional lattice, we study an anomaly-free chiral model (11112) of four\nleft-movers and one right-mover with strong interactions. Exact computations of\nrelevant S-matrices illustrate that for high-momentum states, a negative\nenergy-gap (E<0) develops; the bound state and its constituents, which have the\nsame quantum numbers but opposite chiralities, fill the same energy-state so\nthat chiral symmetries are preserved; for low-momentum states, the negative\nenergy-gap vanishes and the bound state dissolves into its constituents near\nzero energy. As a consequence of the gauge-anomaly cancellation and the index\ntheorem for flavor-singlet anomalies, the net number of zero-modes pushed down\ninto and pumped out from the zero-energy level by the gauge field is zero.",
        "positive": "Lattice study of area law for double-winding Wilson loops: We study the double-winding Wilson loops in the SU(N) Yang-Mills theory on\nthe lattice. We discuss how the area law falloff of the double-winding Wilson\nloop average is modified by changing the enclosing contours C1 and C2 for\nvarious values of the number of color N. By using the strong coupling\nexpansion, we evaluate the double-winding Wilson loop average in the lattice\nSU(N) Yang-Mills theory. Moreover, we compute the double-winding Wilson loop\naverage by lattice Monte Carlo simulations for SU(2) and SU(3). We further\ndiscuss the results from the viewpoint of the Non-Abelian Stokes theorem in the\nhigher representations."
    },
    {
        "anchor": "Towards Weyl fermions on the lattice without artefacts: In spite of the breakthrough in non-perturbative chiral gauge theories during\nthe last decade, the present formulation has stubborn artefacts. Independently\nof the fermion representation one is confronted with unwanted CP violation and\ninfinitely many undetermined weight factors. Renormalization group identifies\nthe culprit. We demonstrate the procedure on Weyl fermions in a real\nrepresentation.",
        "positive": "Gluons in the lattice SU(2) classical field: The SU(2) gluonic correlation functions, glueball effective masses in the\n$J^{P}=0^{+}$, $2^{+}$ and $0^{-}$ channels were calculated from the lattice\nclassical gauge configurations which were obtained by smoothing the thermal\ngauge configurations through the improved cooling method. The instanton-induced\nattractive force in the $0^{+}$ channel and the repulsive force in the $0^-$\nchannel are confirmed in the Monte Carlo simulation. There is evidence that the\ninstanton vacuum contribution to the $0^+$ glueball mass is significant."
    },
    {
        "anchor": "Stochastic calculation of the Dirac spectrum on the lattice and a\n  determination of chiral condensate in 2+1-flavor QCD: We compute the chiral condensate in 2+1-flavor QCD through the spectrum of\nlow-lying eigenmodes of Dirac operator. The number of eigenvalues of the Dirac\noperator is evaluated using a stochastic method with an eigenvalue filtering\ntechnique on the background gauge configurations generated by lattice QCD\nsimulations including the effects of dynamical up, down and strange quarks\ndescribed by the Mobius domain-wall fermion formulation. The low-lying spectrum\nis related to the chiral condensate, which is one of the leading order\nlow-energy constants in chiral effective theory, as dictated by the\nBanks-Casher relation. The spectrum shape and its dependence on the sea quark\nmasses calculated in numerical simulations are consistent with the expectation\nfrom one-loop chiral perturbation theory. After taking the chiral limit as well\nas the continuum limit using the data at three lattice spacings ranging\n0.080-0.045 fm, we obtain $\\Sigma^{1/3}$(2 GeV) = 270.0(4.9) MeV, with the\nerror combining those from statistical and from various sources of systematic\nerrors. Finite volume effect is confirmed to be under control by a direct\ncomparison of the results from two different volumes at the lightest available\nsea quarks corresponding to 230 MeV pions.",
        "positive": "Stability of the Bulk Phase Diagram of the SU(2) Lattice Gauge Theory\n  with Fundamental - Adjoint Action: Using improved mean field and strong coupling expansions we re-analyse the\nbulk phase diagram of the fundamental-adjoint action of the SU(2) Lattice Gauge\nTheory. We find that the qualitative features of the bulk phase diagram are\nrobust and unchanged by the inclusion of higher order terms. On the other hand,\nsome of the quantitative features, such as the location of the endpoint of the\nline of bulk phase transitions, seem to be strongly dependent on the higher\nterms of the strong coupling expansion."
    },
    {
        "anchor": "Landau gauge gluon and ghost propagators from lattice QCD with Nf=2\n  twisted mass fermions at finite temperature: We investigate the temperature dependence of the Landau gauge gluon and ghost\npropagators in lattice QCD with two flavors of maximally twisted mass fermions.\nFor these propagators we provide and analyze data which corresponds to pion\nmass values between 300 and 500 MeV. For the gluon propagator we find that both\nthe longitudinal and transversal component change smoothly in the crossover\nregion, while the ghost propagator exhibits only a very weak temperature\ndependence. For momenta between 0.4 and 3.0 GeV we give a parametrization for\nour lattice data. It may serve as input to studies which employ continuum\nfunctional methods.",
        "positive": "Renormalization Group Study of the soliton mass on the (lambda\n  Phi^4)_{1+1} lattice model: We compute, on the $(\\lambda \\Phi^4)_{1+1}$ model on the lattice, the soliton\nmass by means of two very different numerical methods. First, we make use of a\n``creation operator'' formalism, measuring the decay of a certain correlation\nfunction. On the other hand we measure the shift of the vacuum energy between\nthe symmetric and the antiperiodic systems. The obtained results are fully\ncompatible.\n  We compute the continuum limit of the mass from the perturbative\nRenormalization Group equations. Special attention is paid to ensure that we\nare working on the scaling region, where physical quantities remain unchanged\nalong any Renormalization Group Trajectory. We compare the continuum value of\nthe soliton mass with its perturbative value up to one loop calculation. Both\nquantities show a quite satisfactory agreement. The first is slightly bigger\nthan the perturbative one; this may be due to the contributions of higher order\ncorrections."
    },
    {
        "anchor": "Determinant Calculations with Random Walk Worldline Loops: We propose to calculate bosonic and fermionic determinants with some general\nfield background, and the corresponding 1-loop effective actions by evaluating\nrandom walk worldline loops generated statistically on the lattice. This is\nillustrated by some numerical calculations for constant gauge field backgrounds\nand then discussed for the general case.",
        "positive": "Mixing of B mesons and Decay Constants with the Non-Perturbatively\n  Improved Action: Several quantities relevant to phenomenological studies of the mixing of\nneutral B mesons are computed on the lattice. Our main results are: f_{Bd}\nsqrt(B_{Bd})=206(28)(7) MeV, f_{Bs} sqrt(B_{Bs})/f_{Bd}sqrt(B_{Bd})=1.16(7). We\nalso obtain the related quantities f_{Bs}sqrt(B{Bs})=237(18)(8) MeV, f_{Bd}=\n174(22)(+7-0)(-4-0) MeV, f_{Bs}= 204(15)(+7-0)(+3-0) MeV,\nf_{Bs}/f_{Bd}=1.17(4)(+0-1), f_{Bd}/f_{Ds}=0.74(5). After combining our results\nwith the experimental world average (Delta m_d), we predict (Delta\nm_s)=15.8(2.1)(3.3) ps^{-1}. We have also computed the relevant parameters for\nmixing of neutral D mesons which may be useful in some extensions of the\nStandard Model. All the quantities were obtained from a quenched simulation\nwith a non-perturbatively improved Clover action at beta=6.2, corresponding to\na lattice spacing 1/a=2.7(1) GeV, on a sample of 200 gauge-field\nconfigurations. A discussion of the main systematic errors is also presented."
    },
    {
        "anchor": "Series representation; Pade' approximants and critical behavior in QCD\n  at nonzero T and $mu_B$: We discuss the analytic continuation beyond $\\mu/T \\simeq 1$ in QCD at\nnonzero T and $\\mu$ by use of the Pade' approximants. The slope of the critical\nline obtained in this way increases at large $\\mu$ with respect to the second\norder Taylor result.In the hot phase Pade' and Taylor approximants coincide,\nsuggesting a very large, and possibly infinite, radius of convergence of the\nTaylor series in this thermodynamic region.",
        "positive": "Electroweak Transitions Involving Resonances: The increasing importance of hadronic resonances in our understanding of the\nStandard Model is underscored by recent advancements in lattice Quantum\nChromodynamics (QCD) calculations. We review recent developments, with a\nparticular emphasis on electroweak transitions that result in two-hadron final\nstates. Additionally, we present the finite-volume lattice QCD methodologies\nthat are pivotal in such studies in the context of preliminary results from the\n$B\\to \\pi\\pi\\ell\\bar{\\nu}$."
    },
    {
        "anchor": "A Universal Fractal Structure of 2D Quantum Gravity for c > 1: We investigate the fractal structure of $2d$ quantum gravity coupled to\nmatter by measuring the distributions of so-called baby universes. We\ndemonstrate that the method works well as long as $c \\leq 1$. For $c >1$ it is\nnot clear what distribution to expect. However, we observe strikingly similar\ndistributions for various kinds of matter fields with the same $c$. This\nindicate that there might be some range of $c >1$ where the central charge of\nthe matter fields alone determines the fractal structure of gravity coupled to\nmatter. The hypothesis that the string susceptibility $\\g = 1/3$ is found to be\ncompatible with the data for $1 < c \\leq 4$.",
        "positive": "The eigSUMR inverter for overlap fermion: We discuss the usage and applicability of deflation methods for the overlap\nlattice Dirac operator, focussing on calculating the eigenvalues using a method\nsimilar to the eigCG algorithm used for other Dirac operators. The overlap\noperator, which contains several theoretical advantages over other formulations\nof lattice Quantum Chromodynamics, is more computationally expensive because it\nrequires the computation of the matrix sign function. The principle change made\ncompared to deflation methods for other formulations of lattice QCD is that it\nis necessary for best performance to tune or relax the accuracy of the matrix\nsign function as the computation proceeds.\n  We adapt the eigCG algorithm for two inversion algorithms for overlap\nfermions, GMRESR(relCG) and GMRESR(relSUMR). Before deflation, the rate of\nconvergence of these routines in terms of iterations is similar, but, since the\nShifted Unitary Minimal Residual (SUMR) algorithm only requires one call to the\nmatrix sign function compared to the two calls required for Conjugate Gradient\n(CG), SUMR is usually preferred for single inversions of the Dirac operator. We\nconstruct bounds for the required accuracy of the matrix sign function during\nthe eigenvalue calculation. For the SUMR algorithm, we use a Galerkin\nprojection to perform the deflation; while for the CG algorithm, we are able to\nuse a considerably superior spectral pre-conditioner. The superior performance\nof the spectral preconditioner, and its need for less accurate eigenvalues,\nalmost erodes SUMR's advantage over CG as an inversion algorithm.\n  We see factor of three gains for the inversion algorithm from the deflation\non our small test lattices. There is, however, a significant cost in the\neigenvalue calculation because we cannot relax the accuracy of the matrix sign\nfunction as aggressively when calculating the eigenvalues as we do while\nperforming the inversions."
    },
    {
        "anchor": "On the critical line of 2+1 flavor QCD: We determine the curvature of the (pseudo)critical line of QCD with $n_f$=2+1\nstaggered fermions at nonzero temperature and quark density, by analytic\ncontinuation from imaginary chemical potentials. Monte Carlo simulations are\nperformed adopting the HISQ/tree action discretization, as implemented in the\ncode by the MILC collaboration, suitably modified to include a nonzero\nimaginary baryon chemical potential. We work on a line of constant physics, as\ndetermined in Ref.\\cite{Bazavov:2011nk}, adjusting the couplings so as to keep\nthe strange quark mass $m_s$ fixed at its physical value, with a light to\nstrange mass ratio $m_l/m_s=1/20$. In the present investigation we set the\nchemical potential at the same value for the three quark species,\n$\\mu_l=\\mu_s\\equiv \\mu$. We explore lattices of different spatial extensions,\n$16^3\\times 6$ and $24^3\\times 6$, to check for finite size effects, and\npresent results on a $32^3 \\times 8$ lattice, to check for finite cut-off\neffects. We discuss our results for the curvature $\\kappa$ of the critical line\nat $\\mu = 0$, which indicate $\\kappa=0.018(4)$, and compare them with previous\nlattice determinations by alternative methods and with experimental\ndeterminations of the freeze-out curve.",
        "positive": "Non-perturbative renormalization of the static vector current and its\n  O(a)-improvement in quenched QCD: We carry out the renormalization and the Symanzik O(a)-improvement programme\nfor the static vector current in quenched lattice QCD. The scale independent\nratio of the renormalization constants of the static vector and axial currents\nis obtained non-perturbatively from an axial Ward identity with Wilson-type\nlight quarks and various lattice discretizations of the static action. The\nimprovement coefficients cVstat and bVstat are obtained up to O(g_0^4)-terms by\nenforcing improvement conditions respectively on the axial Ward identity and a\nthree-point correlator of the static vector current. A comparison between the\nnon-perturbative estimates and the corresponding one-loop results shows a\nnon-negligible effect of the O(g_0^4)-terms on the improvement coefficients but\na good accuracy of the perturbative description of the ratio of the\nrenormalization constants."
    },
    {
        "anchor": "Stability of complex Langevin dynamics in effective models: The sign problem at nonzero chemical potential prohibits the use of\nimportance sampling in lattice simulations. Since complex Langevin dynamics\ndoes not rely on importance sampling, it provides a potential solution.\nRecently it was shown that complex Langevin dynamics fails in the disordered\nphase in the case of the three-dimensional XY model, while it appears to work\nin the entire phase diagram in the case of the three-dimensional SU(3) spin\nmodel. Here we analyse this difference and argue that it is due to the presence\nof the nontrivial Haar measure in the SU(3) case, which has a stabilizing\neffect on the complexified dynamics. The freedom to modify and stabilize the\ncomplex Langevin process is discussed in some detail.",
        "positive": "Results from 2+1 flavours of SLiNC fermions: QCD results are presented for a 2+1 flavour fermion clover action (which we\ncall the SLiNC action). A method of tuning the quark masses to their physical\nvalues is discussed. In this method the singlet quark mass is kept fixed, which\nsolves the problem of different renormalisations (for singlet and non-singlet\nquark masses) occuring for non-chirally invariant lattice fermions. This\nprocedure enables a wide range of quark masses to be probed, including the case\nwith a heavy up-down quark mass and light strange quark mass. Preliminary\nresults show the correct splittings for the baryon (octet and) decuplet\nspectrum."
    },
    {
        "anchor": "Centre symmetric 3d effective actions for thermal SU(N) Yang-Mills from\n  strong coupling series: We derive three-dimensional, Z(N)-symmetric effective actions in terms of\nPolyakov loops by means of strong coupling expansions, starting from thermal\nSU(N) Yang-Mills theory in four dimensions on the lattice. An earlier action in\nthe literature, corresponding to the (spatial) strong coupling limit, is thus\nextended by several higher orders, as well as by additional interaction terms.\nWe provide analytic mappings between the couplings of the effective theory and\nthe parameters $N_\\tau,\\beta$ of the original thermal lattice theory, which can\nbe systematically improved. We then investigate the deconfinement transition\nfor the cases SU(2) and SU(3) by means of Monte Carlo simulations of the\neffective theory. Our effective models correctly reproduce second order 3d\nIsing and first order phase transitions, respectively. Furthermore, we\ncalculate the critical couplings $\\beta_c(N_\\tau)$ and find agreement with\nresults from simulations of the 4d theory at the few percent level for\n$N_\\tau=4-16$.",
        "positive": "Anisotropic Lattice and Its Application to Quark Gluon Plasma: We have studied the link-integration method for the improved actions. With\nthis method the $\\eta$ parameter in the medium to strong coupling regions is\nobtained. Effects of the self-energy terms for the $\\eta$ parameters are small\nin the regions of $\\beta$ and $\\eta$ studied. After these investigations, the\nanisotropic lattice is used for the calculation of transport coefficients of\nthe quark gluon plasma."
    },
    {
        "anchor": "Exploring the conformal window: SU(2) gauge theory on the lattice: We study the SU(2) gauge theory on the lattice with different numbers of\nfermions in the fundamental representation of the gauge group to explore the\ngauge theory phase diagram. We find evidence for an infrared fixed point for\nten flavors. The theory with six flavors shows behaviors compatible with the\nexistence of a (quasi) stable fixed point, but the large errors in the present\ndata do not allow for decisive confirmation of this.",
        "positive": "$B_s \\to D_s \\ell \u03bd$ Form Factors and the Fragmentation Fraction Ratio\n  $f_s/f_d$: We present a lattice quantum chromodynamics determination of the scalar and\nvector form factors for the $B_s \\rightarrow D_s \\ell \\nu$ decay over the full\nphysical range of momentum transfer. In conjunction with future experimental\ndata, our results will provide a new method to extract $|V_{cb}|$, which may\nelucidate the current tension between exclusive and inclusive determinations of\nthis parameter. Combining the form factor results at non-zero recoil with\nrecent HPQCD results for the $B \\rightarrow D \\ell \\nu$ form factors, we\ndetermine the ratios $f^{B_s \\rightarrow D_s}_0(M_\\pi^2) / f^{B \\rightarrow\nD}_0(M_K^2) = 1.000(62)$ and $f^{B_s \\rightarrow D_s}_0(M_\\pi^2) / f^{B\n\\rightarrow D}_0(M_\\pi^2) = 1.006(62)$. These results give the fragmentation\nfraction ratios $f_s/f_d =\n0.310(30)_{\\mathrm{stat.}}(21)_{\\mathrm{syst.}}(6)_{\\mathrm{theor.}}(38)_{\\mathrm{latt.}}\n$ and $f_s/f_d =\n0.307(16)_{\\mathrm{stat.}}(21)_{\\mathrm{syst.}}(23)_{\\mathrm{theor.}}(44)_{\\mathrm{latt.}}$,\nrespectively. The fragmentation fraction ratio is an important ingredient in\nexperimental determinations of $B_s$ meson branching fractions at hadron\ncolliders, in particular for the rare decay ${\\cal B}(B_s \\rightarrow \\mu^+\n\\mu^-)$. In addition to the form factor results, we make the first prediction\nof the branching fraction ratio $R(D_s) = {\\cal B}(B_s\\to D_s\\tau\\nu)/{\\cal\nB}(B_s\\to D_s\\ell\\nu) = 0.301(6)$, where $\\ell$ is an electron or muon. Current\nexperimental measurements of the corresponding ratio for the semileptonic\ndecays of $B$ mesons disagree with Standard Model expectations at the level of\nnearly four standard deviations. Future experimental measurements of $R(D_s)$\nmay help understand this discrepancy."
    },
    {
        "anchor": "Confining properties of 2-color QCD at finite density: We study the confining properties of QCD with two colors across the finite\ndensity phase transition. A disorder parameter detecting dual superconductivity\nof the QCD vacuum is used as a probe for the confinement/deconfinement phase\ntransition.",
        "positive": "Dynamic Critical Behavior of Percolation Observables in the 2d Ising\n  Model: We present preliminary results of our numerical study of the critical\ndynamics of percolation observables for the two-dimensional Ising model. We\nconsider the (Monte-Carlo) short-time evolution of the system obtained with a\nlocal heat-bath method and with the global Swendsen-Wang algorithm. In both\ncases, we find qualitatively different dynamic behaviors for the magnetization\nand Omega, the order parameter of the percolation transition. This may have\nimplications for the recent attempts to describe the dynamics of the QCD phase\ntransition using cluster observables."
    },
    {
        "anchor": "Finite size mass shift formula for stable particles revisited: Luescher's finite size mass shift formula in a periodic finite volume,\ninvolving forward scattering amplitudes in the infinite volume, is revisited\nfor the two stable distinguishable particle system. The generalized mass shift\nformulae for the boson and fermion are derived in the boson-boson and\nfermion-boson systems, respectively. The nucleon mass shift is discussed in the\nnucleon-pion system.",
        "positive": "Overlap lattice fermion in a gravitational field: We construct a lattice Dirac operator of overlap type that describes the\npropagation of a Dirac fermion in an external gravitational field. The local\nLorentz symmetry is manifestly realized as a lattice gauge symmetry, while it\nis believed that the general coordinate invariance is restored only in the\ncontinuum limit. Our doubler-free Dirac operator satisfies the conventional\nGinsparg-Wilson relation and possesses gamma_5 hermiticity with respect to the\ninner product, which is suggested by the general coordinate invariance. The\nlattice index theorem in the presence of a gravitational field holds, and the\nclassical continuum limit of the index density reproduces the Dirac genus.\nReduction to a single Majorana fermion is possible for 8k+2 and 8k+4\ndimensions, but not for 8k dimensions, which is consistent with the existence\nof the global gravitational/gauge anomalies in 8k dimensions. Other Lorentz\nrepresentations, such as the spinor-vector and the bi-spinor representations,\ncan also be treated. Matter fields with a definite chirality (with respect to\nthe lattice-modified chiral matrix) are briefly considered."
    },
    {
        "anchor": "Lattice QCD calculations of nucleon transverse momentum-dependent parton\n  distributions using clover and domain wall fermions: We present a lattice QCD calculation of transverse momentum dependent parton\ndistribution functions (TMDs) of protons using staple-shaped Wilson lines. For\ntime-reversal odd observables, we calculate the generalized Sivers and\nBoer-Mulders transverse momentum shifts in SIDIS and DY cases, and for T-even\nobservables we calculate the transversity related to the tensor charge and the\ngeneralized worm-gear shift. The calculation is done on two different n_f=2+1\nensembles: domain-wall fermion (DWF) with lattice spacing 0.084 fm and pion\nmass of 297 MeV, and clover fermion with lattice spacing 0.114 fm and pion mass\nof 317 MeV. The results from those two different discretizations are consistent\nwith each other.",
        "positive": "Continuum Limit Physics from 2+1 Flavor Domain Wall QCD: We present physical results obtained from simulations using 2+1 flavors of\ndomain wall quarks and the Iwasaki gauge action at two values of the lattice\nspacing $a$, ($a^{-1}$=\\,1.73\\,(3)\\,GeV and $a^{-1}$=\\,2.28\\,(3)\\,GeV). On the\ncoarser lattice, with $24^3\\times 64\\times 16$ points, the analysis of ref.[1]\nis extended to approximately twice the number of configurations. The ensembles\non the finer $32^3\\times 64\\times 16$ lattice are new. We explain how we use\nlattice data obtained at several values of the lattice spacing and for a range\nof quark masses in combined continuum-chiral fits in order to obtain results in\nthe continuum limit and at physical quark masses. We implement this procedure\nat two lattice spacings, with unitary pion masses in the approximate range\n290--420\\,MeV (225--420\\,MeV for partially quenched pions). We use the masses\nof the $\\pi$ and $K$ mesons and the $\\Omega$ baryon to determine the physical\nquark masses and the values of the lattice spacing. While our data are\nconsistent with the predictions of NLO SU(2) chiral perturbation theory, they\nare also consistent with a simple analytic ansatz leading to an inherent\nuncertainty in how best to perform the chiral extrapolation that we are\nreluctant to reduce with model-dependent assumptions about higher order\ncorrections. Our main results include $f_\\pi=124(2)_{\\rm stat}(5)_{\\rm\nsyst}$\\,MeV, $f_K/f_\\pi=1.204(7)(25)$ where $f_K$ is the kaon decay constant,\n$m_s^{\\bar{\\textrm{MS}}}(2\\,\\textrm{GeV})=(96.2\\pm 2.7)$\\,MeV and\n$m_{ud}^{\\bar{\\textrm{MS}}}(2\\,\\textrm{GeV})=(3.59\\pm 0.21)$\\,MeV\\,\n($m_s/m_{ud}=26.8\\pm 1.4$) where $m_s$ and $m_{ud}$ are the mass of the\nstrange-quark and the average of the up and down quark masses respectively,\n$[\\Sigma^{\\msbar}(2 {\\rm GeV})]^{1/3} = 256(6)\\; {\\rm MeV}$, where $\\Sigma$ is\nthe chiral condensate, the Sommer scale $r_0=0.487(9)$\\,fm and\n$r_1=0.333(9)$\\,fm."
    },
    {
        "anchor": "Continuum scaling in expansions effective at a large lattice spacing: A new class of truncation schemes of delta expansion on the lattice is\nstudied. We show that the order of expansion in delta which is introduced as\nthe dilation parameter can be taken large enough and the result gives rise to\nthe Borel transformation with respect to the relevant variable in the lattice\nmodels. The explicit simulation of the continuum scaling from the expansion\neffective at large spacings is investigated in anharmonic oscillators, d=2\nnon-linear sigma model at large N and Gross-Neveu model with Wilson fermions.",
        "positive": "On the entropy bound of three dimensional simplicial gravity: It is proven that the partition function of 3-dimensional simplicial gravity\nhas an exponential upper bound with the following assumption: any three\ndimensional sphere $S^3$ is constructed by repeated identification of\nneighboring links and neighboring triangles in the boundary of a simplicial\n3-ball. This assumption is weaker than the one proposed by other authors."
    },
    {
        "anchor": "Non-perturbative mass spectrum of an extra-dimensional orbifold: We analyse non-perturbatively a five-dimensional SU(2) gauge theory\ncompactified on the S^1/Z_2 orbifold. In particular, we present simulation\nresults for the mass spectrum of the theory, which contains a Higgs and a\nphoton. The Higgs mass is found to be free of divergences without fine-tuning.\nThe photon mass is non-zero, thus providing us with the first lattice evidence\nfor a Higgs mechanism derived from an extra dimension. Data from the static\npotential are consistent with dimensional reduction at low energies.",
        "positive": "Temporal quark and gluon propagators: measuring the quasiparticle masses: We calculate the Coulomb gauge temporal quark and gluon propagators in\nquenched QCD. From the temporal quark and gluon propagators, dispersion\nrelations and quasiparticle masses are determined by means of the Maximum\nEntropy Method."
    },
    {
        "anchor": "Intermediate window observable for the hadronic vacuum polarization\n  contribution to the muon $g-2$ from O$(a)$ improved Wilson quarks: Following the publication of the new measurement of the anomalous magnetic\nmoment of the muon, the discrepancy between experiment and the theory\nprediction from the $g-2$ theory initiative has increased to $4.2\\,\\sigma$.\nRecent lattice QCD calculations predict values for the hadronic vacuum\npolarization contribution that are larger than the data-driven estimates,\nbringing the Standard Model prediction closer to the experimental measurement.\nEuclidean time windows in the time-momentum representation of the hadronic\nvacuum polarization contribution to the muon $g-2$ can help clarify the\ndiscrepancy between the phenomenological and lattice predictions. We present\nour calculation of the intermediate distance window contribution using\n$N_\\mathrm{f}=2+1$ flavors of O$(a)$ improved Wilson quarks. We employ\nensembles at six lattice spacings below $0.1\\,$fm and pion masses down to the\nphysical value. We present a detailed study of the continuum limit, using two\ndiscretizations of the vector current and two independent sets of improvement\ncoefficients. Our result at the physical point displays a tension of\n$3.9\\,\\sigma$ with a recent evaluation of the intermediate window based on the\ndata-driven method.",
        "positive": "Fermion-Higgs model with strong Wilson-Yukawa coupling in two dimensions: The fermion mass spectrum is studied in the quenched approximation in the\nstrong coupling vortex phase (VXS) of a globally U(1)$_L \\otimes$U(1)$_R$\nsymmetric scalar-fermion model in two dimensions. In this phase fermion\ndoublers can be completely removed from the physical spectrum by means of a\nstrong Wilson-Yukawa coupling. The lowest lying fermion spectrum in this phase\nconsists most probably only of a massive Dirac fermion which has charge zero\nwith respect to the $U(1)_L$ group. We give evidence that the fermion which is\ncharged with respect to that subgroup is absent in the VXS phase. When the\n$U(1)_L$ gauge fields are turned on, the neutral fermion may couple chirally to\nthe massive vector boson state in the confinement phase. The outcome is very\nsimilar to our findings in the strong coupling symmetric phase (PMS) of\nfermion-Higgs models with Wilson-Yukawa coupling in four dimensions, with the\nexception that in four dimensions the neutral fermion does most probably\ndecouple from the bosonic bound states."
    },
    {
        "anchor": "Quenched chiral logarithms in lattice QCD with exact chiral symmetry: We examine quenched chiral logarithms in lattice QCD with overlap Dirac\nquark. For 100 gauge configurations generated with the Wilson gauge action at $\n\\beta = 5.8 $ on the $ 8^3 \\times 24 $ lattice, we compute quenched quark\npropagators for 12 bare quark masses. The pion decay constant is extracted from\nthe pion propagator, and from which the lattice spacing is determined to be\n0.147 fm. The presence of quenched chiral logarithm in the pion mass is\nconfirmed, and its coefficient is determined to be $ \\delta = 0.203 \\pm 0.014\n$, in agreement with the theoretical estimate in quenched chiral perturbation\ntheory. Further, we obtain the topological susceptibility of these 100 gauge\nconfigurations by measuring the index of the overlap Dirac operator. Using a\nformula due to exact chiral symmetry, we obtain the $ \\eta' $ mass in quenched\nchiral perturbation theory, $ m_{\\eta'} = (901 \\pm 64) $ Mev, and an estimate\nof $ \\delta = 0.197 \\pm 0.027 $, which is in good agreement with that\ndetermined from the pion mass.",
        "positive": "Remarks on the Gribov Problem in Direct Maximal Center Gauge: We review the equivalence of maximal center gauge fixing to the problem of\nfinding the best fit, to a given lattice gauge field, by a thin vortex\nconfiguration. This fit is necessarily worst at the location of P-plaquettes.\nWe then compare the fits achieved in Gribov copies generated by (i)\nover-relaxation; (ii) over-relaxation after Landau gauge preconditioning; and\n(iii) simulated annealing. Simulated annealing yields the best fit if all links\non the lattice are included, but the situation changes if we consider only the\nlattice volume exterior to P-plaquettes. In this exterior region, the fit is\nbest for Gribov copies generated by over-relaxation, and worst for Gribov\ncopies generated after Landau gauge preconditioning. The two fitting criteria\n(including or not including the P-plaquettes) yield string tensions differing\nby -34% to +20% respectively, relative to the full string tension. Our usual\nprocedure (``quenched minimization'') seems to be a compromise between these\ncriteria, and yields string tensions at an intermediate value close to the full\nstring tension."
    },
    {
        "anchor": "Finite Density Fat QCD: Lattice formulation of Finite Baryon Density QCD is problematic from computer\nsimulation point of view; it is well known that for light quark masses the\nreconstructed partition function fails to be positive in a wide region of\nparameter space. For large bare quark masses, instead, it is possible to obtain\nmore sensible results; problems are still present but restricted to a small\nregion. We present evidence for a saturation transition independent from the\ngauge coupling $\\beta$ and for a transition line that, starting from the\ntemperature critical point at $\\mu=0$, moves towards smaller $\\beta$ with\nincreasing $\\mu$ as expected from simplified phenomenological arguments.",
        "positive": "Neutral Kaon Mixing Beyond the Standard Model with $n_f=2+1$ Chiral\n  Fermions Part 1: Bare Matrix Elements and Physical Results: We compute the hadronic matrix elements of the four-quark operators relevant\nfor $K^0-{\\bar K^0}$ mixing beyond the Standard Model. Our results are from\nlattice QCD simulations with $n_f=2+1$ flavours of domain-wall fermion, which\nexhibit continuum-like chiral-flavour symmetry. The simulations are performed\nat two different values of the lattice spacing ($a\\sim0.08$ and $a\\sim 0.11 \\,\n\\fm $) and with lightest unitary pion mass $\\sim 300\\, \\MeV$. For the first\ntime, the full set of relevant four-quark operators is renormalised\nnon-perturbatively through RI-SMOM schemes; a detailed description of the\nrenormalisation procedure is presented in a companion paper. We argue that the\nintermediate renormalisation scheme is responsible for the discrepancies found\nby different collaborations. We also study different normalisations and\ndetermine the matrix elements of the relevant four-quark operators with a\nprecision of $\\sim 5\\%$ or better."
    },
    {
        "anchor": "Dual variables for the SU(2) lattice gauge theory at finite temperature: We study the three-dimensional SU(2) lattice gauge theory at finite\ntemperature using an observable which is dual to the Wilson line. This\nobservable displays a behaviour which is the reverse of that seen for the\nWilson line. It is non-zero in the confined phase and becomes zero in the\ndeconfined phase. At large distances, it's correlation function falls off\nexponentially in the deconfined phase and remains non-zero in the confined\nphase. The dual variable is non-local and has a string attached to it which\ncreates a Z(2) interface in the system. It's correlation function measures the\nstring tension between oppositely oriented Z(2) domains. The construction of\nthis variable can also be made in the four-dimensional theory where it measures\nthe surface tension between oppositely oriented Z(2) domains.",
        "positive": "Density matrix renormalization group approach to a two-dimensional\n  bosonic model: Density matrix renormalization group (DMRG) is applied to a (1+1)-dimensional\n$\\lambda\\phi^4$ model to study spontaneous breakdown of discrete $Z_2$ symmetry\nnumerically. We obtain the critical coupling $(\\lambda/\\mu^2)_{\\rm c}=59.89\\pm\n0.01$ and the critical exponent $\\beta=0.1264\\pm 0.0073$, which are consistent\nwith the Monte Carlo and the exact results, respectively. The results are based\non extrapolation to the continuum limit with lattice sizes $L=250,500$, and\n1000. We show that the lattice size L=500 is sufficiently close to the the\nlimit $L\\to\\infty$ \\cite{Sugihara:2004qr}."
    },
    {
        "anchor": "Probing the tensor structure of lattice three-gluon vertex in Landau\n  gauge: In this paper we test an approximate method that is often used in lattice\nstudies of the Landau gauge three-gluon vertex. The approximation consists in\ndescribing the lattice correlator with tensor bases from the continuum theory.\nWith the help of vertex reconstruction, we show that this \"continuum\" approach\nmay lead, for general kinematics, to significant errors in vertex tensor\nrepresentations. Such errors are highly unwelcome, as they can lead to wrong\nquantitative estimates for vertex form factors and related quantities of\ninterest, like the three-gluon running coupling. As a possible solution, we\ndemonstrate numerically and analytically that there exist special kinematic\nconfigurations for which the vertex tensor structures can be described exactly\non the lattice. For these kinematics, the dimensionless tensor elements are\nequal to the continuum ones, regardless of the details of the lattice\nimplementation. We ran our simulations for an $SU(2)$ gauge theory in two and\nthree spacetime dimensions, with Wilson and $\\mathcal{O}(a^2)$ tree-level\nimproved gauge actions. Our results and conclusions can be straightforwardly\ngeneralised to higher dimensions and, with some precautions, to other lattice\ncorrelators, like the ghost-gluon, quark-gluon and four-gluon vertices.",
        "positive": "Blocking from continuum and monopoles in gluodynamics: We review the method of blocking of topological defects from continuum used\nas a non--perturbative tool to construct effective actions for these defects.\nThe actions are formulated in the continuum limit while the couplings of these\nactions can be derived from simple observables calculated numerically on\nlattices with a finite lattice spacing. We demonstrate the success of the\nmethod in deriving the effective actions for Abelian monopoles in the pure\nSU(2) gauge models in an Abelian gauge. In particular, we discuss the\ngluodynamics in three and four space--time dimensions at zero and non--zero\ntemperatures. Besides the action the quantities of our interest are the\nmonopole density, the magnetic Debye mass and the monopole condensate."
    },
    {
        "anchor": "Random Matrices and the Glasgow Method: A simple non-Hermitean random matrix (RM) model is used to study the Glasgow\nmethod of finite-density lattice QCD. The zeros of the RM partition function\nare evaluated through an averaging procedure, involving the zeros of the RM\n'propagator matrix' in the complex chemical-potential plane. The nature of the\nuncertainty affecting the results is similar to that produced by rounding\nerrors in computing the known analytic result. This similarity is exploited to\ngive quantitative estimates on the relationship between the size of the matrix\nand the number of configurations needed to achieve a given precision. For the\nquenched ensemble considered here, the relationship is exponential.",
        "positive": "On the semimetal-insulator transition and Lifshitz transition in\n  simulations of mono-layer graphene: We report on the status of ongoing Hybrid-Monte-Carlo simulations of the\ntight-binding model of mono-layer graphene. We present results concerning the\nsemimetal-insulator phase transition, whereby two-body interactions are modeled\nby a partially screened Coulomb potential which takes into account screening by\nelectrons in the lower $\\sigma$-orbitals. We obtain evidence that finite-size\neffects may still be present in the current estimate of the critical coupling\nstrength $\\alpha_C$, which was previously extracted from simulations on\nlattice-sizes up to $N_x=N_y=18$. We also present preliminary results\nconcerning the Neck-disrupting Lifshitz transition which occurs at finite\nFermion-density in the limit of vanishing two-body interactions. A sign-problem\nis circumvented by using a spin-dependent chemical potential in our\nsimulations."
    },
    {
        "anchor": "Phase structures of strong coupling lattice QCD with overlap fermions at\n  finite temperature and chemical potential: We perform the first study of lattice QCD with overlap fermions at finite\ntemperature $T$ and chemical potential $\\mu$. We start from the Taylor expanded\noverlap fermion action, and derive in the strong coupling limit the effective\nfree energy by mean field approximation. On the ($\\mu,T$) plane and in the\nchiral limit, there is a tricritical point, separating the second order chiral\nphase transition line at small $\\mu$ and large $T$, and first order chiral\nphase transition line at large $\\mu$ and small $T$.",
        "positive": "Core -- a New Computational Technique for Lattice Systems: The COntractor REnormalization group (CORE) method, a new approach to solving\nHamiltonian lattice systems, is introduced. The method combines contraction and\nvariational techniques with the real-space renormalization group approach. It\napplies to lattice systems of infinite extent and is ideal for studying phase\nstructure and critical phenomena. The CORE approximation is systematically\nimprovable and can treat systems with dynamical fermions. The method is tested\nusing the 1+1-dimensional Ising model."
    },
    {
        "anchor": "Supersymmetry restoration in lattice formulations of 2D\n  $\\mathcal{N}=(2,2)$ WZ model based on the Nicolai map: For lattice formulations of the two-dimensional $\\mathcal{N}=(2,2)$\nWess--Zumino (2D $\\mathcal{N}=(2,2)$ WZ) model on the basis of the Nicolai map,\nwe show that supersymmetry (SUSY) and other symmetries are restored in the\ncontinuum limit without fine tuning, to all orders in perturbation theory. This\nprovides a theoretical basis for use of these lattice formulations for\ncomputation of correlation functions.",
        "positive": "Chiral symmetry restoration and the Z3 sectors of QCD: Quenched SU(3) lattice gauge theory shows three phase transitions, namely the\nchiral, the deconfinement and the Z3 phase transition. Knowing whether or not\nthe chiral and the deconfinement phase transition occur at the same temperature\nfor all Z3 sectors could be crucial to understand the underlying microscopic\ndynamics. We use the existence of a gap in the Dirac spectrum as an order\nparameter for the restoration of chiral symmetry. We find that the spectral gap\nopens up at the same critical temperature in all Z3 sectors in contrast to\nearlier claims in the literature."
    },
    {
        "anchor": "An analysis of the Lattice QCD spectra for $D^*_{s0}(2317)$ and\n  $D^*_{s1}(2460)$: In this talk I present the results obtained using effective field theories in\na finite volume from a reanalysis of lattice data on the $KD^{(*)}$ systems,\nwhere bound states of $KD$ and $KD^*$ are found and associated with the states\n$D^*_{s0}(2317)$ and $D^*_{s1}(2460)$, respectively. We confirm the presence of\nsuch states on the lattice data and determine the weight of the $KD$ channel in\nthe wave function of $D^*_{s0}(2317)$ and that of $KD^*$ in the wave function\nof $D^*_{s1}(2460)$. Our results indicate a large meson-meson component in both\ncases.",
        "positive": "Lattice Background Effective Action: a Proposal: We propose a method based on the Schr\\\"odinger functional for computing on\nthe lattice the gauge invariant effective action for external background\nfields. We check this method by studying the U(1) lattice gauge theory in\npresence of a constant magnetic background field."
    },
    {
        "anchor": "Monopole clusters in Abelian projected gauge theories: We show that the monopole currents which one obtains in the maximally Abelian\ngauge of SU(2) fall into two quite distinct classes (when the volume is large\nenough). In each field configuration there is precisely one cluster that\npermeates the whole lattice volume. It has a current density and a magnetic\nscreening mass that scale and it produces the whole of the string tension. The\nremaining clusters have a number density that follows an approximate power law\nproportional to the inverse cube of l where l is the length of the monopole\nworld line in lattice units. These clusters are localised in space-time with\nradii which vary as the square root of l. In terms of the radius r these\n`lumps' have a scale-invariant distribution proportional to (dr/r . 1/{r^4}).\nMoreover they appear not to contribute at all to the string tension. The fact\nthat they are scale-invariant at small distances would seem to rule out an\ninstanton origin.",
        "positive": "Evidence for the reality of singular configurations in SU(2) gauge\n  theory: We consider the SU(2) lattice gauge model and investigate numerically the\ncontinuum limit of the simple center vortices which are singular configurations\nof the gauge fields. We found that the vortices remain alive in the continuum\ntheory. Also we investigate the Creutz ratio and found that for all $\\beta$ it\nvanishes for those field configurations which do not contain the simple center\nvortices inside the considered Wilson loop. It leads us to the conclusion that\nthese singular field configurations play a real role in the continuum theory."
    },
    {
        "anchor": "The string tensions of SU(3) representations: I report on the status of a computation of fundamental and some higher\nrepresentation string tensions in pure gauge SU(3). An order a^2 tadpole\nimproved action and an anisotropic lattice are used. At present, the static\nquark potentials and the string tensions are calculated by measuring Wilson\nloops on an 8^3 x 24 lattice. Wilson loops for higher representations are\nmeasured in terms of Wilson loops of the fundamental representation. At the\nsmall and intermediate distances available, rough agreement with Casimir\nscaling is observed, and no color screening for the 8 representation is seen.",
        "positive": "QCD equation of state at nonzero chemical potential: continuum results\n  with physical quark masses at order mu^2: We determine the equation of state of QCD for nonzero chemical potentials via\na Taylor expansion of the pressure. The results are obtained for N_f=2+1\nflavors of quarks with physical masses, on various lattice spacings. We present\nresults for the pressure, interaction measure, energy density, entropy density,\nand the speed of sound for small chemical potentials. At low temperatures we\ncompare our results with the Hadron Resonance Gas model. We also express our\nobservables along trajectories of constant entropy over particle number. A\nsimple parameterization is given (the Matlab/Octave script parameterization.m,\nsubmitted to the arXiv along with the paper), which can be used to reconstruct\nthe observables as functions of T and mu, or as functions of T and S/N."
    },
    {
        "anchor": "Lattice QCD estimate of the quark-gluon plasma photon emission rate: We present a computation of the photon emission rate of the quark-gluon\nplasma from two-flavor lattice QCD at a temperature of 254 MeV, which follows\nup on the work presented in [1]. We perform a continuum extrapolation of the\nvector-current correlator, and consider a linear combination of the Lorentz\nindices corresponding to a UV-finite spectral function. To extract the spectral\nfunction from the lattice correlators, an ill-posed inverse problem, we model\nthe spectral function with a Pad\\'e ansatz. We further constrain our analysis\nby simultaneously fitting data with different momenta. We present results for a\nmulti-momentum fit including the three smallest momenta available from our\nlattice analysis.",
        "positive": "Lattice energy-momentum tensor from the Yang-Mills gradient flow -- a\n  simpler prescription: In a recent paper [arXiv:1403.4772], we gave a prescription how to construct\na correctly-normalized conserved energy--momentum tensor in lattice gauge\ntheory containing fermions, on the basis of the Yang--Mills gradient flow. In\nthe present note, we give an almost identical but somewhat superior\nprescription with which one can simply set the fermion mass parameter in our\nformulation zero for the massless fermion. This feature will be useful in\napplying our formulation to theories in which the masslessness of the fermion\nis crucial, such as multi-flavor gauge theories with an infrared fixed point."
    },
    {
        "anchor": "Charge Symmetry Breaking in Spin Dependent Parton Distributions and the\n  Bjorken Sum Rule: We present the first determination of charge symmetry violation (CSV) in the\nspin-dependent parton distribution functions of the nucleon. This is done by\ndetermining the first two Mellin moments of the spin-dependent parton\ndistribution functions of the octet baryons from N_f = 2 + 1 lattice\nsimulations. The results are compared with predictions from quark models of\nnucleon structure. We discuss the contribution of partonic spin CSV to the\nBjorken sum rule, which is important because the CSV contributions represent\nthe only partonic corrections to the Bjorken sum rule.",
        "positive": "Screening masses in quenched (2+1)d Yang-Mills theory: universality from\n  dynamics?: We compute the spectrum of gluonic screening-masses in the $0^{++}$ channel\nof quenched 3d Yang-Mills theory near the phase-transition. Our\nfinite-temperature lattice simulations are performed at scaling region, using\nstate-of-art techniques for thermalization and spectroscopy, which allows for\nthorough data extrapolations to thermodynamic limit. Ratios among\nmass-excitations with the same quantum numbers on the gauge theory, 2d Ising\nand $\\lambda\\phi^{4}$ models are compared, resulting in a nice agreement with\npredictions from universality. In addition, a gauge-to-scalar mapping,\npreviously employed to fit QCD Green's functions at deep IR, is verified to\ndynamically describe these universal spectroscopic patterns"
    },
    {
        "anchor": "The leading hadronic contribution to (g-2) of the muon: The chiral\n  behavior using the mixed representation method: We extend our analysis of the leading hadronic contribution to the anomalous\nmagnetic moment of the muon using the mixed representation method to study its\nchiral behavior. We present results derived from local-conserved two-point\nlattice vector correlation functions, computed on a subset of light two-flavor\nensembles made available to us through the CLS effort with pion masses as low\nas 190 MeV. The data is analyzed also using the more standard four-momentum\nmethod. Both methods are systematically compared as the calculations approach\nthe physical point.",
        "positive": "Neutral B Meson Mixing in Unquenched Lattice QCD: We study $B_d$ and $B_s$ mixing in unquenched lattice QCD employing the MILC\ncollaboration gauge configurations that include u, d, and s sea quarks based on\nthe improved staggered quark (AsqTad) action and a highly improved gluon\naction. We implement the valence light quarks also with the AsqTad action and\nuse the nonrelativistic NRQCD action for the valence b quark. We calculate\nhadronic matrix elements necessary for extracting CKM matrix elements from\nexperimental measurements of mass differences $\\Delta M_d$ and $\\Delta M_s$. We\nfind $\\xi = f_{B_s} \\sqrt{\\hat{B}_{B_s}} / f_{B_d} \\sqrt{\\hat{B}_{B_d}} =\n1.258(33)$, $f_{B_d} \\sqrt{\\hat{B}_{B_d}} = 216(15)$ MeV and $f_{B_s}\n\\sqrt{\\hat{B}_{B_s}} = 266(18)$ MeV. We also update previous results for decay\nconstants and obtain $f_{B_d} = 190(13)$ MeV, $f_{B_s} = 231(15)$ MeV and\n$f_{B_s}/f_{B_d} = 1.226(26)$. The new lattice results lead to updated values\nfor the ratio of CKM matrix elements $|V_{td}|/|V_{ts}|$ and for the Standard\nModel prediction for $Br(B_s \\rightarrow \\mu^+ \\mu^-)$ with reduced errors. We\ndetermine $|V_{td}|/|V_{ts}| = 0.214(1)(5)$ and $Br(B_s \\rightarrow \\mu^+\n\\mu^-) = 3.19(19) \\times 10^{-9}$."
    },
    {
        "anchor": "Chiral extrapolation of light-light and heavy-light decay constants in\n  unquenched QCD: We test the one-loop chiral perturbation theory formula on unquenched lattice\ndata of pseudoscalar meson decay constants. The chiral extrapolation including\nthe effect of the chiral logarithm is attempted and its uncertainty is\ndiscussed.",
        "positive": "Anderson Localization in high temperature QCD: background configuration\n  properties and Dirac eigenmodes: We investigate the properties of the background gauge field configurations\nthat act as disorder for the Anderson localization mechanism in the Dirac\nspectrum of QCD at high temperatures. We compute the eigenmodes of the M\\\"obius\ndomain-wall fermion operator on configurations generated for the $SU(3)$ gauge\ntheory with two flavors of fermions, in the temperature range $[0.9,1.9]T_c$.\nWe identify the source of localization of the eigenmodes with gauge\nconfigurations that are self-dual and support negative fluctuations of the\nPolyakov loop $P_L$, in the high temperature sea of $P_L\\sim 1$. The dependence\nof these observations on the boundary conditions of the valence operator is\nstudied. We also investigate the spatial overlap of the left-handed and\nright-handed projected eigenmodes in correlation with the localization and the\ncorresponding eigenvalue. We discuss an interpretation of the results in terms\nof monopole-instanton structures."
    },
    {
        "anchor": "A variational study of two-nucleon systems with lattice QCD: The low-energy spectrum and scattering of two-nucleon systems are studied\nwith lattice quantum chromodynamics using a variational approach. A wide range\nof interpolating operators are used: dibaryon operators built from products of\nplane-wave nucleons, hexaquark operators built from six localized quarks, and\nquasi-local operators inspired by two-nucleon bound-state wavefunctions in\nlow-energy effective theories. Sparsening techniques are used to compute the\ntimeslice-to-all quark propagators required to form correlation-function\nmatrices using products of these operators. Projection of these matrices onto\nirreducible representations of the cubic group, including spin-orbit coupling,\nis detailed. Variational methods are applied to constrain the low-energy\nspectra of two-nucleon systems in a single finite volume with quark masses\ncorresponding to a pion mass of 806 MeV. Results for S- and D-wave phase shifts\nin the isospin singlet and triplet channels are obtained under the assumption\nthat partial-wave mixing is negligible. Tests of interpolating-operator\ndependence are used to investigate the reliability of the energy spectra\nobtained and highlight both the strengths and weaknesses of variational\nmethods. These studies and comparisons to previous studies using the same\ngauge-field ensemble demonstrate that interpolating-operator dependence can\nlead to significant effects on the two-nucleon energy spectra obtained using\nboth variational and non-variational methods, including missing energy levels\nand other discrepancies. While this study is inconclusive regarding the\npresence of two-nucleon bound states at this quark mass, it provides robust\nupper bounds on two-nucleon energy levels that can be improved in future\ncalculations using additional interpolating operators and is therefore a step\ntoward reliable nuclear spectroscopy from the underlying Standard Model of\nparticle physics.",
        "positive": "The light bound states of $\\mathcal{N}=1$ supersymmetric SU(3)\n  Yang-Mills theory on the lattice: In this article we summarise our results from numerical simulations of\n$\\mathcal{N}=1$ supersymmetric Yang-Mills theory with gauge group SU(3). We use\nthe formulation of Curci and Veneziano with clover-improved Wilson fermions.\nThe masses of various bound states have been obtained at different values of\nthe gluino mass and gauge coupling. Extrapolations to the limit of vanishing\ngluino mass indicate that the bound states form mass-degenerate\nsupermultiplets."
    },
    {
        "anchor": "Lattice QCD and the anomalous magnetic moment of the muon: The anomalous magnetic moment of the muon, a_mu, has been measured with an\noverall precision of 540 ppb by the E821 experiment at BNL. Since the\npublication of this result in 2004 there has been a persistent tension of 3.5\nstandard deviations with the theoretical prediction of a_mu based on the\nStandard Model. The uncertainty of the latter is dominated by the effects of\nthe strong interaction, notably the hadronic vacuum polarisation (HVP) and the\nhadronic light-by-light (HLbL) scattering contributions, which are commonly\nevaluated using a data-driven approach and hadronic models, respectively. Given\nthat the discrepancy between theory and experiment is currently one of the most\nintriguing hints for a possible failure of the Standard Model, it is of\nparamount importance to determine both the HVP and HLbL contributions from\nfirst principles. In this review we present the status of lattice QCD\ncalculations of the leading-order HVP and the HLbL scattering contributions,\na_mu^hvp and a_mu^hlbl. After describing the formalism to express a_mu^hvp and\na_mu^hlbl in terms of Euclidean correlation functions that can be computed on\nthe lattice, we focus on the systematic effects that must be controlled to\nachieve a first-principles determination of the dominant strong interaction\ncontributions to a_mu with the desired level of precision. We also present an\noverview of current lattice QCD results for a_mu^hvp and a_mu^hlbl, as well as\nrelated quantities such as the transition form factor for pi0 -> gamma*gamma*.\nWhile the total error of current lattice QCD estimates of a_mu^hvp has reached\nthe few-percent level, it must be further reduced by a factor 5 to be\ncompetitive with the data-driven dispersive approach. At the same time, there\nhas been good progress towards the determination of a_mu^hlbl with an\nuncertainty at the 10-15%-level.",
        "positive": "Renormalisation of the energy-momentum tensor in scalar field theory\n  using the Wilson flow: A non-perturbative renormalisation prescription for the energy-momentum\ntensor, based on space-time symmetries along the Wilson flow, has been proposed\nrecently in the context of 4-dimensional gauge theories. We extend this\nconstruction to the case of a scalar field theory, and investigate its\nnumerical feasibility by studying Ward identities in 3-dimensional scalar field\ntheory. After introducing the Wilson flow for the scalar field theory we\ndiscuss its renormalisation properties and the determination of the\nrenormalisation constants for the energy-momentum tensor."
    },
    {
        "anchor": "Two-Nucleon Systems in a Finite Volume: (I) Quantization Conditions: The quantization condition for interacting energy eigenvalues of the\ntwo-nucleon system in a finite cubic volume is derived in connection to the\nnucleon-nucleon scattering amplitudes. This condition is derived using an\nauxiliary (dimer) field formalism that is generalized to arbitrary partial\nwaves in the context of non-relativistic effective field theory. The\nquantization condition presented gives access to the scattering parameters of\nthe two-nucleon systems with arbitrary parity, spin, isospin, angular momentum\nand center of mass motion, from a lattice QCD calculation of the energy\neigenvalues. In particular, as it includes all non-central interactions, such\nas the two-nucleon tensor force, it makes explicit the dependence of the mixing\nparameters of nucleon-nucleon systems calculated from lattice QCD when there is\na physical mixing among different partial-waves, e. g. S-D mixing in the\ndeuteron channel. We provide explicit relations among scattering parameters and\ntheir corresponding point group symmetry class eigenenergies with orbital\nangular momentum l smaller than or equal to 3, and for center of mass boost\nvectors of the form 2\\pi (2n_1, 2n_2, 2n_3)/L, 2\\pi (2n_1, 2n_2, 2n_3+1)/L and\n2\\pi (2n_1+1, 2n_2+1, 2n_3)/L. L denotes the special extent of the cubic volume\nand n_1,n_2,n_3 are integers. Our results are valid below inelastic thresholds\nup to exponential volume corrections that are governed by the pion mass.",
        "positive": "Subtleties and Fancies in Gauge Theory Non Trivial Vacuum: The one loop effective potential for a non-Abelian gauge configuration is\nanalyzed using the background field method. The Savvidy result and the\nnon-Abelian ansatz, the other alternative possible background that generates a\nconstant color magnetic field configuration, are compared. This second\npossibility is very interesting because it avoids the possible coordinate\nsingularity, ${\\rm Det}B_i^a=0$, and it is easy to implement in lattice\nsimulations. We emphasize the interesting dependence of the potential by the\ngauge fixing parameter $\\alpha$, when the loop expansion is performed around a\nnon trivial background configuration. Finally, we point out some crucial\ndifferences in analyzing the vacuum structure between non-Abelian gauge\ntheories and the cases of scalar and Abelian gauge theories."
    },
    {
        "anchor": "Calculation of the Nucleon Axial Form Factor Using Staggered Lattice QCD: The nucleon axial form factor is a dominant contribution to errors in\nneutrino oscillation studies. Lattice QCD calculations can help control theory\nerrors by providing first-principles information on nucleon form factors. In\nthese proceedings, we present preliminary results on a blinded calculation of\n$g_A$ and the axial form factor using HISQ staggered baryons with 2+1+1 flavors\nof sea quarks. Calculations are done using physical light quark masses and are\nabsolutely normalized. We discuss fitting form factor data with the\nmodel-independent $z$ expansion parametrization.",
        "positive": "Determination of the Collins-Soper kernel from Lattice QCD: This work presents a determination of the quark Collins-Soper kernel, which\nrelates transverse-momentum-dependent parton distributions (TMDs) at different\nrapidity scales, using lattice quantum chromodynamics (QCD). This is the first\nsuch determination with systematic control of quark mass, operator mixing, and\ndiscretization effects. Next-to-next-to-leading logarithmic matching is used to\nmatch lattice-calculable distributions to the corresponding TMDs. The\ncontinuum-extrapolated lattice QCD results are consistent with several recent\nphenomenological parameterizations of the Collins-Soper kernel and are precise\nenough to disfavor other parameterizations."
    },
    {
        "anchor": "Recent results in large-N lattice gauge theories: Generalizations of QCD in which the number of colors N is taken to infinity\nare characterized by profound mathematical properties, with far-reaching\nimplications for fundamental problems and for phenomenological issues alike. In\nthis contribution, after a brief introduction to the theoretical motivation for\nstudying the large-N limit, the role of lattice computations in large-N gauge\ntheories is discussed, and a selection of interesting results obtained in\nrecent years is highlighted. Finally, some promising research directions for\nfuture studies are pointed out.",
        "positive": "Classification and Generalization of Minimal-doubling actions: We propose a method to control the number of species of lattice fermions,\nwhich yields new classes of minimally doubled lattice fermions with one exact\nchiral symmetry and exact locality. We classify all the known minimally doubled\nfermions into two types based on the locations of the propagator poles in the\nBrillouin zone. We also study higher-dimensional extension of them and show it\ntends to be more difficult to realize minimal-doubling in higher dimensions."
    },
    {
        "anchor": "Condensation of vortices in the X-Y model in 3d: a disorder parameter: A disorder parameter is constructed which signals the condensation of\nvortices. The construction is tested by numerical simulations on lattice.",
        "positive": "Another mean field treatment in the strong coupling limit of lattice QCD: We discuss the QCD phase diagram in the strong coupling limit of lattice QCD\nby using a new type of mean field coming from the next-to-leading order of the\nlarge dimensional expansion. The QCD phase diagram in the strong coupling limit\nrecently obtained by using the monomer-dimer-polymer (MDP) algorithm has some\ndifferences in the phase boundary shape from that in the mean field results. As\none of the origin to explain the difference, we consider another type of\nauxiliary field, which corresponds to the point-splitting mesonic composite.\nFermion determinant with this mean field under the anti-periodic boundary\ncondition gives rise to a term which interpolates the effective potentials in\nthe previously proposed zero and finite temperature mean field treatments.\nWhile the shift of the transition temperature at zero chemical potential is in\nthe desirable direction and the phase boundary shape is improved, we find that\nthe effects are too large to be compatible with the MDP simulation results."
    },
    {
        "anchor": "Electric and magnetic U(1) currents in lattice confinement studies: Making use of an Ehrenfest-Maxwell relation we show that in Abelian projected\nSU(2), in the maximal Abelian gauge, the dynamical electric charge density\ngenerated by the coset fields, gauge fixing and ghosts shows antiscreening as\nin the case of the non-Abelian charge.",
        "positive": "Complex Langevin analysis of the spontaneous symmetry breaking in\n  dimensionally reduced super Yang-Mills models: In recent years the complex Langevin method (CLM) has proven a powerful\nmethod in studying statistical systems which suffer from the sign problem. Here\nwe show that it can also be applied to an important problem concerning why we\nlive in four-dimensional spacetime. Our target system is the type IIB matrix\nmodel, which is conjectured to be a nonperturbative definition of type IIB\nsuperstring theory in ten dimensions. The fermion determinant of the model\nbecomes complex upon Euclideanization, which causes a severe sign problem in\nits Monte Carlo studies. It is speculated that the phase of the fermion\ndeterminant actually induces the spontaneous breaking of the SO(10) rotational\nsymmetry, which has direct consequences on the aforementioned question. In this\npaper, we apply the CLM to the 6D version of the type IIB matrix model and show\nclear evidence that the SO(6) symmetry is broken down to SO(3). Our results are\nconsistent with those obtained previously by the Gaussian expansion method."
    },
    {
        "anchor": "Chiral Effective Lagrangian and Quark Masses: The status of lattice determinations of quark masses is reviewed (with the\nexception of m_b). Attempts to extract the low-energy constants in the\neffective chiral Lagrangian are discussed, with special emphasis on those\ncouplings which are required to test the hypothesis of a massless up-quark.\nFurthermore, the issue of quenched chiral logarithms is addressed.",
        "positive": "Prospects for $\u03b3^\\star \u03b3^\\star \\to \u03c0\u03c0$ via lattice QCD: The $\\gamma^\\star \\gamma^\\star \\to \\pi \\pi$ scattering amplitude plays a key\nrole in a wide range of phenomena, including understanding the inner structure\nof scalar resonances as well as constraining the hadronic contributions to the\nanomalous magnetic moment of the muon. In this work, we explain how the\ninfinite-volume Minkowski amplitude can be constrained from finite-volume\nEuclidean correlation functions. The relationship between the finite-volume\nEuclidean correlation functions and the desired amplitude holds up to energies\nwhere $3\\pi$ states can go on shell, and is exact up to exponentially small\ncorrections that scale like $\\mathcal{O}(e^{-m_\\pi L})$, where $L$ is the\nspatial extent of the cubic volume and $m_\\pi$ is the pion mass. In order to\nimplement this formalism and remove all power-law finite volume errors, it is\nnecessary to first obtain $\\pi \\pi \\to \\pi\\pi$, $\\pi \\gamma^\\star \\to \\pi$,\n$\\gamma^\\star \\to\\pi\\pi$, and $\\pi\\pi\\gamma^\\star \\to\\pi\\pi$ amplitudes; all of\nwhich can be determined via lattice quantum chromodynamic calculations."
    },
    {
        "anchor": "Heavy flavour precision physics from Nf = 2 + 1 + 1 lattice simulations: We present precision lattice calculations of the pseudoscalar decay constants\nof the charmed sector as well as determinations of the bottom quark mass and\nits ratio to the charm quark mass. We employ Nf=2+1+1 dynamical quark gauge\nconfigurations generated by the European Twisted Mass Collaboration, using data\nat three values of the lattice spacing and pion masses as low as 210 MeV.\nStrange and charm sea quark masses are close to their physical values.",
        "positive": "Off-diagonal Gluon Mass Generation and Infrared Abelian Dominance in the\n  Maximally Abelian Gauge in Lattice QCD: We study effective mass generation of off-diagonal gluons and infrared\nabelian dominance in the maximally abelian (MA) gauge. Using the SU(2) lattice\nQCD, we investigate the propagator and the effective mass of the gluon field in\nthe MA gauge with the U(1)$_3$ Landau gauge fixing. The Monte Carlo simulation\nis performed on the $12^3 \\times 24$ lattice with $2.2 \\le \\beta \\le 2.4$, and\nalso on the $16^4$ and $20^4$ lattices with $2.3 \\le \\beta \\le 2.4$. In the MA\ngauge, the diagonal gluon component $A_\\mu^3$ shows long-range propagation, and\ninfrared abelian dominance is found for the gluon propagator. In the MA gauge,\nthe off-diagonal gluon component $A_\\mu^\\pm$ behaves as a massive vector boson\nwith the effective mass $M_{\\rm off} \\simeq 1.2$ GeV in the region of $r \\gsim\n0.2$ fm, and its propagation is limited within short range. We conjecture that\ninfrared abelian dominance can be interpreted as infrared inactivity of the\noff-diagonal gluon due to its large mass generation induced by the MA gauge\nfixing."
    },
    {
        "anchor": "QCD simulations with staggered fermions on GPUs: We report on our implementation of the RHMC algorithm for the simulation of\nlattice QCD with two staggered flavors on Graphics Processing Units, using the\nNVIDIA CUDA programming language. The main feature of our code is that the GPU\nis not used just as an accelerator, but instead the whole Molecular Dynamics\ntrajectory is performed on it. After pointing out the main bottlenecks and how\nto circumvent them, we discuss the obtained performances. We present some\npreliminary results regarding OpenCL and multiGPU extensions of our code and\ndiscuss future perspectives.",
        "positive": "Adjoint \"quarks\" on coarse anisotropic lattices: Implications for string\n  breaking in full QCD: A detailed study is made of four dimensional SU(2) gauge theory with static\nadjoint ``quarks'' in the context of string breaking. A tadpole-improved action\nis used to do simulations on lattices with coarse spatial spacings $a_s$,\nallowing the static potential to be probed at large separations at a\ndramatically reduced computational cost. Highly anisotropic lattices are used,\nwith fine temporal spacings $a_t$, in order to assess the behavior of the\ntime-dependent effective potentials. The lattice spacings are determined from\nthe potentials for quarks in the fundamental representation. Simulations of the\nWilson loop in the adjoint representation are done, and the energies of\nmagnetic and electric ``gluelumps'' (adjoint quark-gluon bound states) are\ncalculated, which set the energy scale for string breaking. Correlators of\ngauge-fixed static quark propagators, without a connecting string of spatial\nlinks, are analyzed. Correlation functions of gluelump pairs are also\nconsidered; similar correlators have recently been proposed for observing\nstring breaking in full QCD and other models. A thorough discussion of the\nrelevance of Wilson loops over other operators for studies of string breaking\nis presented, using the simulation results presented here to support a number\nof new arguments."
    },
    {
        "anchor": "Lattice Study of the $H$ Dibaryon: The mass of the lowest spin-zero, strangeness-$(-2)$ flavor singlet state in\nthe dibaryon sector has been calculated in quenched QCD on $16^3\\times32$ and\n$24^3\\times32$ lattices at $\\beta=5.85$ to study whether the energy of the\nproposed $H$ dibaryon is near or below the $\\Lambda\\Lambda$ threshold.\nPreliminary results indicate that finite lattice volume artifacts overestimate\nthe binding, and that on the largest lattice $m_H$ is of the order of $100\\MeV$\nabove the $\\Lambda\\Lambda$ threshold.",
        "positive": "WChPT analysis of twisted mass lattice data: We perform a Wilson Chiral Perturbation Theory (WChPT) analysis of quenched\ntwisted mass lattice data. The data were generated by two independent groups\nwith three different choices for the critical mass. For one choice, the\nso-called pion mass definition, one observes a strong curvature for small quark\nmasses in various mesonic observables (''bending phenomenon''). Performing a\ncombined fit to the next-to-leading (NLO) expressions, we find that WChPT\ndescribes the data very well and the fits provide very reasonable values for\nthe low-energy parameters."
    },
    {
        "anchor": "Determination of Low-Energy Constants of Wilson Chiral Perturbation\n  Theory: By matching Wilson twisted mass lattice QCD determinations of pseudoscalar\nmeson masses to Wilson Chiral Perturbation Theory we determine the low-energy\nconstants $W'_6$, $W'_8$ and their linear combination $c_2$. We explore the\ndependence of these low-energy constants on the choice of the lattice action\nand on the number of dynamical flavours.",
        "positive": "Theoretical Developments in Lattice Gauge Theory for Applications in\n  Double-beta Decay Processes and Quantum Simulation: Double beta decays are rare nuclear processes that can occur in two modes:\ntwo-neutrino double beta decay, observed in the Standard Model, and\nneutrinoless double beta decay, a hypothetical process with profound\nimplications for Particle Physics. To draw reliable conclusions from their\nexperimental constraints, it is necessary to have accurate predictions of the\nunderlying hadronic interactions described by quantum chromodynamics (QCD), a\nnon-Abelian gauge theory with the symmetry group SU(3). QCD predictions require\nnon-perturbative methods for calculating observables, and lattice QCD (LQCD), a\nnumerical method based on QCD formulated on a finite space-time grid, is the\nonly reliable first-principles technique for obtaining quantitative results.\nHowever, LQCD needs formal prescriptions to match numerical results with\nobservables. This thesis provides such prescriptions for double beta decays\nusing the finite volume effects in the LQCD framework. Matching relations that\nconnect two-nucleon double beta decay amplitudes to quantities accessible via\nLQCD calculations, namely the nuclear matrix elements and two-nucleon energy\nspectra in a finite volume are provided. The impact of uncertainties is\nexamined on the precision with which low-energy constants of the corresponding\neffective field theories can be determined from future LQCD calculations.\n  Hamiltonian simulation of QCD is another non-perturbative method of solving\nQCD which can be more suitable in some cases than the conventional LQCD. The\nrise of tensor network methods and quantum simulation has made Hamiltonian\nsimulation of lattice gauge theories (LGTs) a reality. Towards the goal of\nsimulating QCD, a loop-string-hadron (LSH) formulation of an SU(3) LGT with\nmatter in 1+1 dimensions is developed in this thesis, motivated by recent\nstudies that showed the LSH formulation of an SU(2) LGT to be advantageous over\nother formulations."
    },
    {
        "anchor": "Monopoles at Finite Volume and Temperature in SU(2) Lattice Gauge Theory: We resolve a discrepancy between the SU(2) spacial string tension at finite\ntemperature, and the value obtained by monopoles in the maximum Abelian gauge.\nPrevious work had incorrectly omitted a term due to Dirac sheets. When this\nterm is included, the monopole and full SU(2) determinations of the spacial\nstring tension agree to within the statistical errors of the monopole\ncalculation.",
        "positive": "HotQCD on Multi-GPU Systems: We present $\\texttt{SIMULATeQCD}$, HotQCD's software for performing lattice\nQCD calculations on GPUs. Started in late 2017 and intended as a full\nreplacement of the previous single GPU lattice QCD code used by the HotQCD\ncollaboration, our software has been developed into an extensive framework for\nlattice QCD calculations distributed on multiple GPUs over many compute nodes.\nThe code is built on C++, CUDA, and MPI and leverages modern C++ language\nfeatures to provide high-level data structures, objects, and algorithms that\nallow users to express lattice QCD calculations in an intuitive way without\nsacrificing performance. Implemented algorithms range from gradient flow,\ncorrelator measurements, and mixed precision conjugate gradient solvers all the\nway to full HISQ gauge field configuration generation using RHMC. After\nsuccessful deployment in large-scale computing projects, we want to share the\nresult of our efforts with the lattice QCD community by making it publicly\navailable. In these proceedings, we will present some of the key features of\nour code, demonstrate its ease of use, and show benchmarks of performance\ncritical kernels on state-of-the-art supercomputers."
    },
    {
        "anchor": "Towards measuring the eta' mass with N_f=2+1 staggered fermions: Because the propagators of flavor-singlet states incorporate disconnected\ndiagrams, they are uniquely sensitive to any differences in the actions\ngoverning sea and valence fermions on the lattice. As such, they present an\nimportant test of the validity of the ``fourth-root trick'' in the staggered\nfermion formulation. The pseudoscalar's relationship to topological charge also\nmakes it of theoretical interest. We present preliminary results from our\nmeasurements of flavor-singlet pseudoscalar mesons on 2+1 flavor Asqtad\nlattices, and discuss some strategies for improving the signal-to-error ratio\nof disconnected singlet correlators.",
        "positive": "Finite-size scaling in nucleon axial charge from 2+1-flavor DWF lattice\n  QCD: We report the current status of the on-going lattice-QCD calculations of\nnucleon isovector axial charge, g_A, using the RBC/UKQCD 2+1-flavor dynamical\ndomain-wall fermion ensembles at lattice cutoff of about a^{-1}=1.4 GeV in a\nspatial volume (L = 4.6 fm)^3. The result from the ensemble with m_\\pi = 250\nMeV pion mass, corresponding to the finite-size scaling parameter m_\\pi L \\sim\n5.8, agrees well with an earlier result at a^{-1}=1.7 GeV, L = 2.8 fm, and\nm_\\pi = 420 MeV, with similar m_\\pi L. This suggests the systematic error from\nexcited-state contamination is small in both ensembles and about 10-% deficit\nin g_A we are observing is likely a finite-size effect that scales with m_\\pi\nL. We also report the result from the lighter, m_\\pi = 170 MeV ensemble."
    },
    {
        "anchor": "CP violation in QCD: Among the parameters of QCD is one that results in CP violation when\nnon-vanishing. This is closely related to possible quark mass terms. It is\nconventionally interpreted in terms of gauge field topology or alternatively in\nterms of phases in the quark masses. There is no experimental evidence for this\nparameter having a non-zero value, a puzzle for theories involving unification.",
        "positive": "Template Composite Dark Matter : SU(2) gauge theory with 2 fundamental\n  flavours: We present a non perturbative study of SU(2) gauge theory with two\nfundamental Dirac flavours. We discuss how the model can be used as a template\nfor composite Dark Matter (DM). We estimate one particular interaction of the\nDM candidate with the Standard Model : the interaction through photon exchange\ncomputing the electric polarizability of the DM candidate. Finally, we briefly\ndiscuss the viability of the model given the present experimental constraints."
    },
    {
        "anchor": "One loop matching coefficients for a variant overlap action--and some of\n  its simpler relatives: I present one-loop perturbative calculations of matching coefficients between\nmatrix elements in continuum regulated QCD and lattice QCD with overlap\nfermions, with emphasis a recently-proposed variant discretization of the\noverlap. These fermions have extended (``fat link'') gauge connections. The\nscale for evaluation of the running coupling constant (in the context of the\nLepage-Mackenzie fixing scheme) is also given.\n  A variety of results (for additive mass renormalization, local currents, and\nsome non-penguin four-fermion operators) for naive, Wilson, clover, and overlap\nactions are shown.",
        "positive": "Flavour physics and Lattice QCD: averages of lattice inputs for the\n  Unitarity Triangle Analysis: We review recent results of Lattice QCD calculations relevant for flavour\nphysics. We discuss in particular the hadronic parameters entering the\namplitudes of K0-K0bar, D0-D0bar and B0-B0bar mixing, the B- and D-meson decay\nconstants and the form factors controlling B-meson semileptonic decays. On the\nbasis of these lattice results, which are extensively collected in the paper,\nwe also derive our averages of the relevant hadronic parameters."
    },
    {
        "anchor": "First results for charm physics with a tmQCD valence action: We present preliminary results in the charm sector from a mixed-action setup,\nin which CLS $N_f=2+1$ ensembles are combined with a Wilson twisted mass\nvalence action. We study the continuum and chiral limits of charm quark\nobservables such as the decay constants $f_{D_{(s)}}$ and the renormalized\ncharm-quark mass.",
        "positive": "Low-lying baryon resonances from lattice QCD: Recent results studying the masses and widths of low-lying baryon resonances\nin lattice QCD are presented. The $S$-wave $N\\pi$ scattering lengths for both\ntotal isospins $I = 1/2$ and $I = 3/2$ are inferred from the finite-volume\nspectrum below the inelastic threshold together with the $I = 3/2$ $P$-wave\ncontaining the $\\Delta(1232)$ resonance. A lattice QCD computation employing a\ncombined basis of three-quark and meson-baryon interpolating operators with\ndefinite momentum to determine the coupled channel $\\Sigma\\pi$-$N\\overline{K}$\nscattering amplitude in the $\\Lambda(1405)$ region is also presented. Our\nresults support the picture of a two-pole structure suggested by theoretical\napproaches based on $SU(3)$ chiral symmetry and unitarity."
    },
    {
        "anchor": "Dirac Spectrum of the Wilson Dirac Operator for QCD with Two Colors: We study the lattice artefacts of the Wilson Dirac operator for QCD with two\ncolors and fermions in the fundamental representation from the viewpoint of\nchiral perturbation theory. These effects are studied with the help of the\nfollowing spectral observables: the level density of the Hermitian Wilson Dirac\noperator, the distribution of chirality over the real eigenvalues, and the\nchiral condensate for the quenched as well as for the unquenched theory. We\nprovide analytical expressions for all these quantities. Moreover we derive\nconstraints for the level density of the real eigenvalues of the non-Hermitian\nWilson Dirac operator and the number of additional real modes. The latter is a\ngood measure for the strength of lattice artefacts. All computations are\nconfirmed by Monte Carlo simulations of the corresponding random matrix theory\nwhich agrees with chiral perturbation theory of two color QCD with Wilson\nfermions.",
        "positive": "Testing the AdS/CFT correspondence by Monte Carlo calculation of BPS and\n  non-BPS Wilson loops in 4d N=4 super-Yang-Mills theory: We test the AdS/CFT correspondence by calculating Wilson loops in N = 4 super\nYang-Mills theory on R*S^3 in the planar limit. Our method is based on a novel\nlarge-N reduction, which reduces the problem to Monte Carlo calculations in the\nplane-wave matrix model or the BMN matrix model, which is a 1d gauge theory\nwith 16 supercharges. By using the gauge-fixed momentumspace simulation, we\nobtain results respecting 16 supersymmetries. We report on the Monte Carlo\nresults for the BPS circular Wilson loop, which reproduce the exact result up\nto strong coupling. As a future prospect, we calculate a track-shapedWilson\nloop from the gravity side, which shows that a clear test of the AdS/CFT for\nthe non-BPS case is also feasible."
    },
    {
        "anchor": "Form factors for $B$ to $Kll$ semileptonic decay from three-flavor\n  lattice QCD: We study the $B \\to Kl^+l^-$ semileptonic decay process in three-flavor\nlattice QCD. We analyze several ensembles generated by the MILC collaboration\nat different lattice spacings and sea-quark masses. We use the asqtad improved\nstaggered action for the light quarks and the clover action with the Fermilab\ninterpretation for the heavy $b$ quark. We present preliminary results for the\nvector current induced form factors for a range of kaon energies. Our analysis\nincludes chiral and continuum extrapolations based on SU(2) staggered \\chi PT.",
        "positive": "Some remarks on Lefschetz thimbles and complex Langevin dynamics: Lefschetz thimbles and complex Langevin dynamics both provide a means to\ntackle the numerical sign problem prevalent in theories with a complex weight\nin the partition function, e.g. due to nonzero chemical potential. Here we\ncollect some findings for the quartic model, and for U(1) and SU(2) models in\nthe presence of a determinant, which have some features not discussed before,\ndue to a singular drift. We find evidence for a relation between classical\nrunaways and stable thimbles, and give an example of a degenerate fixed point.\nWe typically find that the distributions sampled in complex Langevin dynamics\nare related to the thimble(s), but with some important caveats, for instance\ndue to the presence of unstable fixed points in the Langevin dynamics."
    },
    {
        "anchor": "Baryon number, strangeness and electric charge fluctuations at zero and\n  non-zero chemical potential: We present results on baryon number, strangeness and electric charge\nfluctuations in QCD at non-zero density and temperature obtained from lattice\ncalculations with almost physical quark masses. At vanishing chemical\npotential, i.e. under conditions almost realized at RHIC and the LHC, quartic\nfluctuations of net baryon number and strangeness are large in a narrow\ntemperature interval characterizing the transition region from the low to the\nhigh temperature phase. Our results are based on Taylor expansions in light and\nstrange quark chemical potentials, i.e. we rigorously compute corrections to\nbulk thermodynamic quantities at non vanishing chemical potential, by\nperforming a Taylor expansion in $\\mu/T$. We find non-monotonic behavior for\nthe radius of convergence of this series, which could be a hint for a critical\nend-point in the ($T,\\mu$)-plane.",
        "positive": "A Lattice Study of the Glue in the Nucleon: By introducing an additional operator into the action and using the\nFeynman-Hellmann theorem we describe a method to determine both the quark line\nconnected and disconnected terms of matrix elements. As an illustration of the\nmethod we calculate the gluon contribution (chromo-electric and chromo-magnetic\ncomponents) to the nucleon mass."
    },
    {
        "anchor": "Calculation of Helium nuclei in quenched lattice QCD: We present results for the binding energies for ^4He and ^3He nuclei\ncalculated in quenched lattice QCD at the lattice spacing of a =0.128 fm with a\nheavy quark mass corresponding to m_pi = 0.8 GeV. Enormous computational cost\nfor the nucleus correlation functions is reduced by avoiding redundancy of\nequivalent contractions stemming from permutation symmetry of protons or\nneutrons in the nucleus and various other symmetries. To distinguish a bound\nstate from an attractive scattering state, we investigate the volume dependence\nof the energy difference between the ground state energy of the nucleus channel\nand the free multi-nucleon states by changing the spatial extent of the lattice\nfrom 3.1 fm to 12.3 fm. A finite energy difference left in the infinite spatial\nvolume limit leads to the conclusion that the measured ground states are\nbounded. It is also encouraging that the measured binding energies and the\nexperimental ones show the same order of magnitude.",
        "positive": "Cluster Percolation and Explicit Symmetry Breaking in Spin Models: Many features of spin models can be interpreted in geometrical terms by means\nof the properties of well defined clusters of spins. In case of spontaneous\nsymmetry breaking, the phase transition of models like the q-state Potts model,\nO(n), etc., can be equivalently described as a percolation transition of\nclusters. We study here the behaviour of such clusters when the presence of an\nexternal field H breaks explicitly the global symmetry of the Hamiltonian of\nthe theory. We find that these clusters have still some interesting\nrelationships with thermal features of the model."
    },
    {
        "anchor": "Resummation of Cactus Diagrams in the Clover Improved Lattice\n  Formulation of QCD: We extend to the clover improved lattice formulation of QCD the resummation\nof cactus diagrams, i.e. a certain class of tadpole-like gauge invariant\ndiagrams. Cactus resummation yields an improved perturbative expansion. We\napply it to the lattice renormalization of some two-fermion operators improving\ntheir one-loop perturbative estimates.",
        "positive": "Improved Superlinks for Higher Spin Operators: Traditional smearing or blocking techniques serve well to increase the\noverlap of operators onto physical states but allow for links orientated only\nalong lattice axes. Recent attempts to construct more general propagators have\nshown promise at resolving the higher spin states but still rely on iterative\nsmearing. We present a new method of superlink construction which creates\nmeared links from (sparse) matrix multiplications, allowing for gluonic\npropagation in arbitrary directions. As an application and example, we compute\nthe positive-parity, even-spin glueball spectrum up to spin 6 for pure gauge\nSU(2) at beta = 6, L = 16, in D = 2+1 dimensions."
    },
    {
        "anchor": "Two-Baryon Potentials and H-Dibaryon from 3-flavor Lattice QCD\n  Simulations: Baryon-baryon potentials are obtained from 3-flavor QCD simulations with the\nlattice volume L ~ 4 fm, the lattice spacing a ~ 0.12 fm, and the\npseudo-scalar-meson mass M_ps =469 - 1171 MeV. The NN scattering phase shift\nand the mass of H-dibaryon in the flavor SU(3) limit are extracted from the\nresultant potentials by solving the Schrodinger equation. The NN phase shift in\nthe SU(3) limit is shown to have qualitatively similar behavior as the\nexperimental data. A bound H-dibaryon in the SU(3) limit is found to exist in\nthe flavor-singlet J^P=0^+ channel with the binding energy of about 26 MeV for\nthe lightest quark mass M_ps = 469 MeV. Effect of flavor SU(3) symmetry\nbreaking on the H-dibaryon is estimated by solving the coupled-channel\nSchrodinger equation for Lambda Lambda - N Xi - Sigma Sigma with the physical\nbaryon masses and the potential matrix obtained in the SU(3) limit: a resonant\nH-dibaryon is found between Lambda Lambda and N Xi thresholds in this\ntreatment.",
        "positive": "Distribution of the Dirac modes in QCD: It was established that distribution of the near-zero modes of the Dirac\noperator is consistent with the Chiral Random Matrix Theory (CRMT) and can be\nconsidered as a consequence of spontaneous breaking of chiral symmetry (SBCS)\nin QCD. The higher-lying modes of the Dirac operator carry information about\nconfinement physics and are not affected by SBCS. We study distributions of the\nnear-zero and higher-lying modes of the overlap Dirac operator within $N_F = 2$\ndynamical simulations. We find that distributions of both near-zero and\nhigher-lying modes are the same and follow the Gaussian Unitary Ensemble of\nRandom Matrix Theory. This means that randomness, while consistent with SBCS,\nis not a consequence of SBCS and is related to some more general property of\nQCD in confinement regime."
    },
    {
        "anchor": "Nucleon structure from generalized parton distributions in lattice QCD: This talk presents results from the QCDSF-UKQCD collaboration for moments of\nleading twist generalized parton distributions in two-flavor lattice QCD based\non O(a) improved Wilson Fermions. We study helicity independent and helicity\nflip GPDs with a focus on densities of quarks in the transverse plane.",
        "positive": "Numerical simulations with two flavours of twisted-mass Wilson quarks\n  and DBW2 gauge action: Discretisation errors in two-flavour lattice QCD with Wilson-quarks and DBW2\ngauge action are investigated by comparing numerical simulation data at two\nvalues of the bare gauge coupling. Both non-zero and zero twisted mass values\nare considered. The results, including also data from simulations using the\nWilson plaquette gauge action, are compared to next-to-leading order chiral\nperturbation theory formulas."
    },
    {
        "anchor": "Oblique correction in a walking lattice theory: I compute the difference of vector and axial vector current correlators in\nthe weak coupling phase of (lattice-regulated) SU(3) gauge theory with two\nflavors of symmetric-representation dynamical fermions. This is a walking\ntheory at the bare parameter values chosen for the simulation. Otherwise, it is\nnot a conventional technicolor candidate. The correlator difference shows\nscaling behavior in the fermion mass, and vanishes in the fermion zero mass\nlimit. Consequences for the phenomenology of similar systems which might be\ncandidates for beyond Standard Model physics are discussed. I check my\nmethodology against ordinary QCD, by computing the Gasser-Leutwyler coefficient\nL_10 and the charged - neutral pion mass difference from an approximate\nparameterization of the correlator.",
        "positive": "Phase transitions in center-stabilized lattice gauge theories: We simulate four-dimensional center-stabilized lattice Yang-Mills theories on\nR^3 x S^1 with a newly developed pseudo-heatbath algorithm. We analyze the\nphase structure of such theories, namely the bulk transition and the\nspontaneous breaking of the center symmetry associated with the compact\ndirection."
    },
    {
        "anchor": "Isothermal and isentropic speed of sound in (2+1)-flavor QCD at non-zero\n  baryon chemical potential: Recently interest in calculations of the speed of sound in QCD under\nconditions like constant temperature $c^2_T$ or constant entropy per net baryon\nnumber $c^2_s$ arose in the discussion of experimental results coming from\nheavy ion experiments. It has been stressed that the former in particular is\nclosely related to higher order cumulants of conserved charge fluctuations that\nare calculated in lattice QCD. We present here results on $c^2_T$ and $c^2_s$\nand compare results at vanishing strangeness chemical potential and vanishing\nnet strangeness number with hadron resonance gas model calculations. We stress\nthe difference of both observables at low temperature arising from the light\nmeson sector, which does not contribute to $c^2_T$.",
        "positive": "Composite Weak Bosons: a Lattice Analysis: We present a lattice analysis of a confining Yang-Mills theory without\nGoldstone boson. We have analytically investigated the model by a strong\ncoupling expansion and by an intensive lattice Monte Carlo simulation using\nstandard lattice QCD methods. We show that this theory is an interesting\ncandidate for describing weak bosons as composite particles."
    },
    {
        "anchor": "Monopoles Vortices and Confinement: The status of our understanding of colour confinement is reviewed.",
        "positive": "Monopole currents and Dirac sheets in U(1) lattice gauge theory: We show that the phases of the 4-dimensional compact U(1) lattice gauge\ntheory are unambiguously characterized by the topological properties of minimal\nDirac sheets as well as of monopole currents lines. We obtain the minimal\nsheets by a simulated-annealing procedure. Our results indicate that the\nequivalence classes of sheet structures are the physical relevant quantities\nand that intersections are not important. In conclusion we get a\npercolation-type view of the phases which holds beyond the particular boundary\nconditions used."
    },
    {
        "anchor": "The electromagnetic form factor of the pion: Results from the lattice: This review contains an overview over recent results for the electromagnetic\niso-vector form factor of the pion obtained in lattice QCD with dynamical\nfermions. Particular attention is given to the extrapolation to the physical\npoint and an easy assessment of the control over the main systematic effects by\nimposing quality criteria and an associated sign code, similar to the ones used\nby the FLAG working group. Also included is a brief discussion of recent\ndevelopments and future challenges concerning the accurate extraction of the\nform factor in the lattice framework.",
        "positive": "The Static Potential in the SU(2) Higgs Model: The static potential in the confinement ``phase'' of the SU(2) Higgs model is\nstudied. In particular, the observation of the screening (called string\nbreaking) of the static quarks by the dynamical light quarks leading to the\nformation of two static-light mesons was not observed before my work in\nnon-Abelian gauge theories. The tool that I employ is lattice gauge simulation.\nThe observable from which the spectrum of the Hamiltonian in presence of two\nstatic quarks can be extracted, is a matrix correlation whose elements are\nconstructed not only from string-type states represented by Wilson loops (like\nin pure gauge theories). Additional matrix elements representing transitions\nfrom string-type to meson-type states and the propagation of meson-type states\nare taken into account. From this basis of states it is possible to extract the\nground state and first excited state static potentials employing a variational\nmethod. The crossing of these two energy levels in the string breaking region\nis clearly visible and the inadequacy of the Wilson loops alone can be\ndemonstrated. I also address the question of the lattice artifacts. For this\npurpose lines of constant physics in the confinement ``phase'' of the model\nhave to be constructed. This problem has only partially been solved.\nNevertheless it is possible to show that the static potentials have remarkable\nscaling properties under a variation of the lattice spacing by a factor two and\nare almost independent of the quartic Higgs coupling."
    },
    {
        "anchor": "A Study of Degenerate Four-quark states in SU(2) Lattice Monte Carlo: The energies of four-quark states are calculated for geometries in which the\nquarks are situated on the corners of a series of tetrahedra and also for\ngeometries that correspond to gradually distorting these tetrahedra into a\nplane. The interest in tetrahedra arises because they are composed of {\\bf\nthree } degenerate partitions of the four quarks into two two-quark colour\nsinglets. This is an extension of earlier work showing that geometries with\n{\\bf two} degenerate partitions (e.g.\\ squares) experience a large binding\nenergy. It is now found that even larger binding energies do not result, but\nthat for the tetrahedra the ground and first excited states become degenerate\nin energy. The calculation is carried out using SU(2) for static quarks in the\nquenched approximation with $\\beta=2.4$ on a $16^3\\times 32$ lattice. The\nresults are analysed using the correlation matrix between different euclidean\ntimes and the implications of these results are discussed for a model based on\ntwo-quark potentials.",
        "positive": "The Loop-Cluster Algorithm for the Case of the 6 Vertex Model: We present the loop algorithm, a new type of cluster algorithm that we\nrecently introduced for the F model. Using the framework of Kandel and Domany,\nwe show how to GENERALIZE the algorithm to the arrow flip symmetric 6 vertex\nmodel. We propose the principle of least possible freezing as the guide to\nchoosing the values of free parameters in the algorithm. Finally, we briefly\ndiscuss the application of our algorithm to simulations of quantum spin\nsystems. In particular, all necessary information is provided for the\nsimulation of spin $\\half$ Heisenberg and $xxz$ models."
    },
    {
        "anchor": "Progress report on the relativistic three-particle quantization\n  condition: We describe recent work on the relativistic three-particle quantization\ncondition, generalizing and applying the original formalism of Hansen and\nSharpe, and of Brice\\~no, Hansen and Sharpe. In particular, we sketch three\nrecent developments: the generalization of the formalism to include K-matrix\npoles; the numerical implementation of the quantization condition in the\nisotropic approximation; and ongoing work extending the description of the\nthree-particle divergence-free K matrix beyond the isotropic approximation.",
        "positive": "The John von Neumann Institute for Computing (NIC): A survey of its\n  supercomputer facilities and its Europe-wide computational science activities: The John von Neumann Institute for Computing (NIC) at the Research Centre\nJuelich, Germany, is one of the leading supercomputing centres in Europe.\nFounded as a national centre in the mid-eighties it now provides more and more\nresources to European scientists. This happens within EU-funded projects (I3HP,\nDEISA) or Europe-wide scientific collaborations. Beyond these activities NIC\nstarted an initiative towards the new EU member states in summer 2004.\nOutstanding research groups are offered to exploit the supercomputers at NIC to\naccelerate their investigations on leading-edge technology.\n  The article gives an overview of the organisational structure of NIC, its\ncurrent supercomputer systems, and its user support. Transnational Access (TA)\nwithin I3HP is described as well as access by the initiative for new EU member\nstates. The volume of these offers and the procedure of how to apply for\nsupercomputer resources is introduced in detail."
    },
    {
        "anchor": "An efficient method to compute the residual phase on a Lefschetz thimble: We propose an efficient method to compute the so-called residual phase that\nappears when performing Monte Carlo calculations on a Lefschetz thimble. The\nmethod is stochastic and its cost scales linearly with the physical volume,\nlinearly with the number of stochastic estimators and quadratically with the\nlength of the extra dimension along the gradient flow. This is a drastic\nimprovement over previous estimates of the cost of computing the residual\nphase. We also report on basic tests of correctness and scaling of the code.",
        "positive": "From spin models to lattice QCD -- the scientific legacy of Peter\n  Hasenfratz: This is a transcript of my conference talk in remembrance of Peter Hasenfratz\nwho deceased earlier in 2016. One of Peter's many important contributions to\nthe lattice community has been the initiation of the first lattice conference\nat CERN in 1982. From among his many important ideas, which Peter contributed\nto our field, I choose to discuss three in some detail and show how they are\ninfluencing the subject today."
    },
    {
        "anchor": "Gauge cooling in complex Langevin for QCD with heavy quarks: We employ a new method, \"gauge cooling\", to stabilize complex Langevin\nsimulations of QCD with heavy quarks. The results are checked against results\nobtained with reweigthing; we find agreement within the estimated errors. The\nmethod allows us to go to previously unaccessible high densities.",
        "positive": "HQET form factors for $B_s\\to K\\ell\u03bd$ decays beyond leading order: We compute semi-leptonic $B_s$ decay form factors using Heavy Quark Effective\nTheory on the lattice. To obtain good control of the $1/m_b$ expansion, one has\nto take into account not only the leading static order but also the terms\narising at $O(1/m_b)$: kinetic, spin and current insertions. We show results\nfor these terms calculated through the ratio method, using our prior results\nfor the static order. After combining them with non-perturbative HQET\nparameters they can be continuum-extrapolated to give the QCD form factor\ncorrect up to $O(1/m_b^2)$ corrections and without $O(\\alpha_s(m_b)^n)$\ncorrections."
    },
    {
        "anchor": "$\u03b7'$-$\u03b7_c$-mixing with improved stochastic estimators: Charmonia are flavour singlet mesons and thus in principle contributions from\ndisconnected quark line diagrams might affect their masses, either directly or\nvia mixing with other flavour singlet channels. We present a first study that\ntakes both effects into account. We employ improved stochastic all-to-all\npropagator techniques (including new methods) to calculate the diagrams that\nappear within the mixing matrix between the $\\eta'$ and the $\\eta_c$. The runs\nare initially performed on $N_f=2$ $16^3\\times 32$ configurations with the\nnon-perturbatively improved Sheikholeslami-Wilson action, both for valence and\nsea quarks.",
        "positive": "Non-$\u03b3_{5}$hermiticity fermions in two dimensions: We construct 2D non-$\\gamma_{5}$hermiticity fermions based on the minimal\ndoubling fermion. We investigate symmetries, reflection positivity, eigenvalue\ndistribution and the number of poles for our fermions. As simple tests for\napplication to the fermion, the Gross-Neveu model in two dimensions is studied\nusing the non-$\\gamma_{5}$hermiticity fermion. We draw the parity broken phase\ndiagram, called Aoki phase and the chiral broken phase diagram for the model\nwith an imaginary chemical potential."
    },
    {
        "anchor": "Kl3 and pion form factors using partially twisted boundary conditions: We compute the Kl3 and pion form factors using partially twisted boundary\nconditions. The twists are chosen so that the Kl3 form factors are calculated\ndirectly at zero momentum transfer (q^2=0), removing the need for a q^2\ninterpolation, while the pion form factor is determined at values of q^2 close\nto q^2=0. The simulations are performed on an ensemble of the RBC/UKQCD\ncollaboration's gauge configurations with Domain Wall Fermions and the Iwaski\ngauge action with an inverse lattice spacing of 1.73(3) GeV. Simulating at a\nsingle pion mass of 330 MeV, we find the pion charge radius to be < r^2>_{330\nMeV}=0.354(31) fm^2 which, using NLO SU(2) chiral perturbation theory,\ntranslates to a value of <r_\\pi^2>=0.418(31) fm^2 for a physical pion. For the\nvalue of the Kl3 form factor, f_{K\\pi}^+(q^2), determined directly at q^2=0, we\nfind a value of f_{K\\pi}^+(0)=0.9742(41) at this particular quark mass, which\nagrees well with our earlier result (0.9774(35)) obtained using the standard,\nindirect method.",
        "positive": "Renormalization of Flavor Singlet and Nonsinglet Fermion Bilinear\n  Operators: We compute the difference in the renormalization of flavor singlet and\nnonsinglet fermion bilinear operators, to two loops in perturbation theory. Our\nresults are applicable to a rather wide class of lattice actions with Symanzik\nimproved gluons, stout links and clover fermions, including the Twisted Mass\nand SLiNC actions.\n  A more detailed presentation of our results, along with relevant references,\nwill appear in a forthcoming publication."
    },
    {
        "anchor": "The three-quark potential and perfect Abelian dominance in SU(3) lattice\n  QCD: We study the static three-quark (3Q) potential for more than 300 different\npatterns of 3Q systems with high statistics, i.e., 1000-2000 gauge\nconfigurations, in SU(3) lattice QCD at the quenched level. For all the\ndistances, the 3Q potential is found to be well described by the Y-ansatz,\ni.e., one-gluon-exchange (OGE) Coulomb plus Y-type linear potential. Also, we\ninvestigate Abelian projection of quark confinement in the context of the dual\nsuperconductor picture proposed by Yoichiro~Nambu~{\\it et al.} in SU(3) lattice\nQCD. Remarkably, quark confinement forces in both Q$\\bar{\\rm Q}$ and 3Q systems\ncan be described only with Abelian variables in the maximally Abelian gauge,\ni.e., $\\sigma_{\\rm Q \\bar Q} \\simeq \\sigma_{\\rm Q \\bar Q}^{\\rm Abel} \\simeq\n\\sigma_{\\rm 3Q} \\simeq \\sigma_{\\rm 3Q}^{\\rm Abel}$, which we call ``perfect\nAbelian dominance'' of quark confinement.",
        "positive": "Strong coupling expansion for Yang-Mills theory at finite temperature: Euclidean strong coupling expansion of the partition function is applied to\nlattice Yang-Mills theory at finite temperature, i.e. for lattices with a\ncompactified temporal direction. The expansions have a finite radius of\nconvergence and thus are valid only for $\\beta<\\beta_c$, where $\\beta_c$\ndenotes the nearest singularity of the free energy on the real axis. The\naccessible temperature range is thus the confined regime up to the\ndeconfinement transition. We have calculated the first few orders of these\nexpansions of the free energy density as well as the screening masses for the\ngauge groups SU(2) and SU(3). The resulting free energy series can be summed up\nand corresponds to a glueball gas of the lowest mass glueballs up to the\ncalculated order. Our result can be used to fix the lower integration constant\nfor Monte Carlo calculations of the thermodynamic pressure via the integral\nmethod, and shows from first principles that in the confined phase this\nconstant is indeed exponentially small. Similarly, our results also explain the\nweak temperature dependence of glueball screening masses below $T_c$, as\nobserved in Monte Carlo simulations. Possibilities and difficulties in\nextracting $\\beta_c$ from the series are discussed."
    },
    {
        "anchor": "A NOVEL LOOK AT THE MICHAEL LATTICE SUM RULES: We reconsider the derivation of the Michael lattice sum rules, which relate\nthe energy and action stored in a flux tube of a quark-antiquark pair to the\nstatic interquark potential, and show that they require essential corrections.\nWe then find, using the coupling constant sum rule of Karsch, that the total\nMinkowski field energy does not match the interquark potential, if one follows\nconventional notions. The implications of this result are discussed.",
        "positive": "Renormalization Constants of Quark Operators for the Non-Perturbatively\n  Improved Wilson Action: We present the results of an extensive lattice calculation of the\nrenormalization constants of bilinear and four-quark operators for the\nnon-perturbatively O(a)-improved Wilson action. The results are obtained in the\nquenched approximation at four values of the lattice coupling by using the\nnon-perturbative RI/MOM renormalization method. Several sources of systematic\nuncertainties, including discretization errors and final volume effects, are\nexamined. The contribution of the Goldstone pole, which in some cases may\naffect the extrapolation of the renormalization constants to the chiral limit,\nis non-perturbatively subtracted. The scale independent renormalization\nconstants of bilinear quark operators have been also computed by using the\nlattice chiral Ward identities approach and compared with those obtained with\nthe RI-MOM method. For those renormalization constants the non-perturbative\nestimates of which have been already presented in the literature we find an\nagreement which is typically at the level of 1%."
    },
    {
        "anchor": "Complex Langevin: Etiology and Diagnostics of its Main Problem: The complex Langevin method is a leading candidate for solving the so-called\nsign problem occurring in various physical situations. Its most vexing problem\nis that in some cases it produces `convergence to the wrong limit'. In the\nfirst part of the paper we go through the formal justification of the method,\nidentify points at which it may fail and identify a necessary and sufficient\ncriterion for correctness. This criterion would, however, require checking\ninfinitely many identities, and therefore is somewhat academic. We propose\ninstead a truncation to the check of a few identities; this still gives a\nnecessary criterion, but a priori it is not clear whether it remains\nsufficient. In the second part we carry out a detailed study of two toy models:\nfirst we identify the reasons why in some cases the method fails, second we\ntest the efficiency of the truncated criterion and find that it works perfectly\nat least in the toy models studied.",
        "positive": "Quarkonium mass splittings in three-flavor lattice QCD: We report on calculations of the charmonium and bottomonium spectrum in\nlattice QCD. We use ensembles of gauge fields with three flavors of sea quarks,\nsimulated with the asqtad improved action for staggered fermions. For the heavy\nquarks we employ the Fermilab interpretation of the clover action for Wilson\nfermions. These calculations provide a test of lattice QCD, including the\ntheory of discretization errors for heavy quarks. We provide, therefore, a\ncareful discussion of the results in light of the heavy-quark effective\nLagrangian. By and large, we find that the computed results are in agreement\nwith experiment, once parametric and discretization errors are taken into\naccount."
    },
    {
        "anchor": "Quantum Spin Formulation of the Principal Chiral Model: We formulate the two-dimensional principal chiral model as a quantum spin\nmodel, replacing the classical fields by quantum operators acting in a Hilbert\nspace, and introducing an additional, Euclidean time dimension. Using coherent\nstate path integral techniques, we show that in the limit in which a large\nrepresentation is chosen for the operators, the low energy excitations of the\nmodel describe a principal chiral model in three dimensions. By dimensional\nreduction, the two-dimensional principal chiral model of classical fields is\nrecovered.",
        "positive": "Meson-meson scattering lengths at maximum isospin from lattice QCD: We summarize our lattice QCD determinations of the pion-pion, pion-kaon and\nkaon-kaon s-wave scattering lengths at maximal isospin with a particular focus\non the extrapolation to the physical point and the usage of next-to-leading\norder chiral perturbation theory to do so. We employ data at three values of\nthe lattice spacing and pion masses ranging from around 230 MeV to around 450\nMeV, applying Luescher's finite volume method to compute the scattering\nlengths. We find that leading order chiral perturbation theory is surprisingly\nclose to our data even in the kaon-kaon case for our entire range of pion\nmasses."
    },
    {
        "anchor": "Flavor symmetry breaking in mixed-action QCD: We study the phase structure of mixed-action QCD with two Wilson sea quarks\nand two chiral valence quarks, starting from the chiral lagrangian. A priori,\nthe effective theory allows for a rich phase structure, including a phase with\na condensate made of sea and valence quarks. Because this would lead to mass\neigenstates that are admixtures of sea and valence fields, pure-sea correlation\nfunctions would depend on valence quark masses, in contradiction with the\nactual setup of mixed-action simulations. Using properties of the chiral Dirac\noperator, we prove that such a phase does not occur, and that this leads to\nbounds on low-energy constants.",
        "positive": "Comparison between Fermion Bag Approach and Complex Langevin Dynamics\n  for Massive Thirring Model at Finite Density in 0 + 1 Dimensions: We consider the massive Thirring model at finite density in 0+1 dimension.\nThe fermion bag approach, Langevin dynamics and complex Langevin dynamics are\nadopted to attack the sign problem for this model. Compared with the complex\nLangevin dynamics, both fermion bag approach and Langvin dynamics avoid the\nsign problem. The fermion density and chiral condensate, which are obtained by\nthese numerical methods, are compared with the exact results. The advantages of\nthe fermion bag approach over the other numerical methods are also discussed."
    },
    {
        "anchor": "Gluon Field Digitization for Quantum Computers: Simulations of gauge theories on quantum computers require the digitization\nof continuous field variables. Digitization schemes that uses the minimum\namount of qubits are desirable. We present a practical scheme for digitizing\n$SU(3)$ gauge theories via its discrete subgroup $S(1080)$. The $S(1080)$\nstandard Wilson action cannot be used since a phase transition occurs as the\ncoupling is decreased, well before the scaling regime. We proposed a modified\naction that allows simulations in the scaling window and carry out classical\nMonte Carlo calculations down to lattice spacings of order $a\\approx 0.08$ fm.\nWe compute a set of observables with sub-percent precision at multiple lattice\nspacings and show that the continuum extrapolated value agrees with the full\n$SU(3)$ results. This suggests that this digitization scheme provides\nsufficient precision for NISQ-era QCD simulations.",
        "positive": "Freeze-out Conditions in Heavy Ion Collisions from QCD Thermodynamics: We present a determination of chemical freeze-out conditions in heavy ion\ncollisions based on ratios of cumulants of net electric charge fluctuations.\nThese ratios can reliably be calculated in lattice QCD for a wide range of\nchemical potential values by using a next-to-leading order Taylor series\nexpansion around the limit of vanishing baryon, electric charge and strangeness\nchemical potentials. From a computation of up to fourth order cumulants and\ncharge correlations we first determine the strangeness and electric charge\nchemical potentials that characterize freeze-out conditions in a heavy ion\ncollision and confirm that in the temperature range 150 MeV < T < 170 MeV the\nhadron resonance gas model provides good approximations for these parameters\nthat agree with QCD calculations on the (5-15)% level. We then show that a\ncomparison of lattice QCD results for ratios of up to third order cumulants of\nelectric charge fluctuations with experimental results allows to extract the\nfreeze-out baryon chemical potential and the freeze-out temperature."
    },
    {
        "anchor": "The Schr\u00f6dinger Functional - a Renormalizable Probe for Non-Abelian\n  Gauge Theories: Following Symanzik we argue that the Schr\\\"odinger functional in lattice\ngauge theories without matter fields has a well-defined continuum limit. Due to\ngauge invariance no extra counter terms are required. The Schr\\\"odinger\nfunctional is, moreover, accessible to numerical simulations. It may hence be\nused to study the scaling properties of the theory and in particular the\nevolution of the renormalized gauge coupling from low to high energies. A\nconcrete proposition along this line is made and the necessary perturbative\nanalysis of the Schr\\\"odinger functional is carried through to 1-loop order.",
        "positive": "Effective $\u03b8$ term by CP-odd electromagnetic background fields: We discuss our study of QCD in the presence of CP-odd electromagnetic (e.m.)\nbackground fields. We investigate the propagation of the CP-odd term from the\ne.m. sector to the strong sector, inducing an effective $\\theta$ term. We\ndiscuss the method we have used in our lattice QCD simulations, and the results\nof our analysis, which are relevant to the determination of the effective\npseudoscalar QED-QCD interactions. We also explore how these CP-odd e.m.\nbackground fields influence the number of the Dirac zero modes in our\nconfigurations."
    },
    {
        "anchor": "Study of the $Z_c^+$ channel using lattice QCD: Recently experimentalists have discovered several charged charmonium-like\nhadrons $Z_c^+$ with unconventional quark content $\\bar cc\\bar d u$. We perform\na search for $Z_c^+$ with mass below $4.2~$GeV in the channel\n$I^G(J^{PC})=1^+(1^{+-})$ using lattice QCD. The major challenge is presented\nby the two-meson states $J/\\psi\\, \\pi$, $\\psi_{2S}\\pi$, $\\psi_{1D}\\pi$, $D\\bar\nD^*$, $D^*\\bar D^*$, $\\eta_c\\rho$ that are inevitably present in this channel.\nThe spectrum of eigenstates is extracted using a number of meson-meson and\ndiquark-antidiquark interpolating fields. For our pion mass of 266~MeV we find\nall the expected two-meson states but no additional candidate for $Z_c^+$ below\n$4.2~$GeV. Possible reasons for not seeing an additional eigenstate related to\n$Z_c^+$ are discussed. We also illustrate how a simulation incorporating\ninterpolators with a structure resembling low-lying two-mesons states seems to\nrender a $Z_c^+$ candidate, which is however not robust after further two-meson\nstates around $4.2~$GeV are implemented.",
        "positive": "Nucleon Structure from Quenched Overlap Fermions: We compute the lowest moments of the nucleon's structure functions using\nquenched overlap fermions at two different lattice spacings. The\nrenormalisation is done nonperturbatively in the RI'-MOM-scheme."
    },
    {
        "anchor": "Numerical simulation of graphene in external magnetic field: In this paper the results of numerical simulation of monolayer graphene in\nexternal magnetic field are presented. The numerical simulation is performed in\nthe effective lattice field theory with noncompact $3 + 1$-dimensional Abelian\nlattice gauge fields and $2 + 1$-dimensional staggered lattice fermions. The\ndependences of fermion condensate and graphene conductivity on the dielectric\npermittivity of substrate for different values of external magnetic field are\ncalculated. It is found that magnetic field shifts insulator-semimetal phase\ntransition to larger values of the dielectric permittivity of substrate. The\nphase diagram of graphene in external magnetic field is drawn.",
        "positive": "Charmed Tetraquarks Tcc and Tcs from Dynamical Lattice QCD Simulations: Charmed tetraquarks $T_{cc}=(cc\\bar{u}\\bar{d})$ and\n$T_{cs}=(cs\\bar{u}\\bar{d})$ are studied through the S-wave meson-meson\ninteractions, $D$-$D$, $\\bar{K}$-$D$, $D$-$D^{*}$ and $\\bar{K}$-$D^{*}$, on the\nbasis of the (2+1)-flavor lattice QCD simulations with the pion mass $m_{\\pi}\n\\simeq $410, 570 and 700 MeV. For the charm quark, the relativistic heavy quark\naction is employed to treat its dynamics on the lattice. Using the HAL QCD\nmethod, we extract the S-wave potentials in lattice QCD simulations, from which\nthe meson-meson scattering phase shifts are calculated. The phase shifts in the\nisospin triplet ($I$=1) channels indicate repulsive interactions, while those\nin the $I=0$ channels suggest attraction, growing as $m_{\\pi}$ decreases. This\nis particularly prominent in the $T_{cc} (J^P=1^+,I=0)$ channel, though neither\nbound state nor resonance are found in the range $m_{\\pi} =410-700$ MeV. We\nmake a qualitative comparison of our results with the phenomenological diquark\npicture."
    },
    {
        "anchor": "Lattice hadron matrix elements with the Schroedinger functional: the\n  case of the first moment of non-singlet quark density: We present the results of a non-perturbative determination of the pion matrix\nelement of the twist-2 operator corresponding to the average momentum of\nnon-singlet quark densities. The calculation is made within the Schroedinger\nfunctional scheme. We report the results of simulations done with the standard\nWilson action and with the non-perturbatively improved clover action and we\nshow that their ratio correctly extrapolates, in the continuum limit, to a\nvalue compatible with the residual correction factor expected from perturbation\ntheory.",
        "positive": "The Logarithmic Triviality of Compact QED Coupled to a Four Fermi\n  Interaction: This is the completion of an exploratory study of Compact lattice Quantum\nElectrodynamics with a weak four-fermi interaction and four species of massless\nfermions. In this formulation of Quantum Electrodynamics massless fermions can\nbe simulated directly and Finite Size Scaling analyses can be performed at the\ntheory's chiral symmetry breaking critical point. High statistics simulations\non lattices ranging from $8^4$ to $24^4$ yield the equation of state, critical\nindices, scaling functions and cumulants. The measurements are well fit with\nthe orthodox hypothesis that the theory is logarithmically trivial and its\ncontinuum limit suffers from Landau's zero charge problem."
    },
    {
        "anchor": "Lattice Study of Radiative $J/\u03c8$ Decay to a Tensor Glueball: The radiative decay of $J/\\psi$ into a pure gauge tensor glueball is studied\nin the quenched lattice QCD formalism. With two anisotropic lattices, the\nmutlipole amplitudes E_1(0), M_2(0) and E_3(0) are obtained to be\n0.114(12)(6)GeV, -0.011(5)(1)GeV, and 0.023(8)(1)GeV, respectively. The first\nerror comes from the statistics, the Q^2 interpolation, and the continuum\nextrapolation, while the second is due to the uncertainty of the scale\nparameter r_0^{-1}=410(20) MeV. Thus the partial decay width\n$\\Gamma(J/\\psi\\rightarrow \\gamma G_{2^{++}})$ is estimated to be 1.01(22)(10)\nkeV which corresponds to a large branch ratio 1.1(2)(1)x10^{-2}. The\nphenomenological implication of this result is also discussed.",
        "positive": "Using the Mass Storage System at ZIB within I3HP: In the framework of I3HP there are two Transnational Access Activities\nrelated to Computational Hadron Physics. One of these activities is access to\nthe mass storage system at Konrad-Zuse-Zentrum fuer Informationstechnik Berlin\n(ZIB). European lattice physics collaborations can apply for mass storage\ncapacity in order to store and share their configurations or other data (see\nhttp://www.zib.de/i3hp/). In this paper formal and technical aspects of usage\nas well as the conformance to the International Lattice DataGrid (ILDG) are\nexplained."
    },
    {
        "anchor": "Study of compact abelian lattice gauge theories: This is a review, intended for lattice nonspecialists, of the studies of the\ncompact abelian gauge theories on the lattice performed by the Aachen lattice\nfield theory group. We discuss in particular the pure compact QED and a U(1)\nlattice gauge theory with charged scalar and fermion fields in four and three\ndimensions. Our data indicate that these lattice theories might define some\ncontinuum field theories, or at least effective field theories with remarkable\nnonperturbative properties like confinement and dynamical mass generation.",
        "positive": "Critical Exponents, Hyperscaling and Universal Amplitude Ratios for Two-\n  and Three-Dimensional Self-Avoiding Walks: We make a high-precision Monte Carlo study of two- and three-dimensional\nself-avoiding walks (SAWs) of length up to 80000 steps, using the pivot\nalgorithm and the Karp-Luby algorithm. We study the critical exponents $\\nu$\nand $2\\Delta_4 -\\gamma$ as well as several universal amplitude ratios; in\nparticular, we make an extremely sensitive test of the hyperscaling relation\n$d\\nu = 2\\Delta_4 -\\gamma$. In two dimensions, we confirm the predicted\nexponent $\\nu = 3/4$ and the hyperscaling relation; we estimate the universal\nratios $\\<R_g^2\\> / \\<R_e^2\\> = 0.14026 \\pm 0.00007$, $\\<R_m^2\\> / \\<R_e^2\\> =\n0.43961 \\pm 0.00034$ and $\\Psi^* = 0.66296 \\pm 0.00043$ (68\\% confidence\nlimits). In three dimensions, we estimate $\\nu = 0.5877 \\pm 0.0006$ with a\ncorrection-to-scaling exponent $\\Delta_1 = 0.56 \\pm 0.03$ (subjective 68\\%\nconfidence limits). This value for $\\nu$ agrees excellently with the\nfield-theoretic renormalization-group prediction, but there is some discrepancy\nfor $\\Delta_1$. Earlier Monte Carlo estimates of $\\nu$, which were $\\approx\\!\n0.592$, are now seen to be biased by corrections to scaling. We estimate the\nuniversal ratios $\\<R_g^2\\> / \\<R_e^2\\> = 0.1599 \\pm 0.0002$ and $\\Psi^* =\n0.2471 \\pm 0.0003$; since $\\Psi^* > 0$, hyperscaling holds. The approach to\n$\\Psi^*$ is from above, contrary to the prediction of the two-parameter\nrenormalization-group theory. We critically reexamine this theory, and explain\nwhere the error lies."
    },
    {
        "anchor": "Lattice Gauge Fixing as Quenching and the Violation of Spectral\n  Positivity: Lattice Landau gauge and other related lattice gauge fixing schemes are known\nto violate spectral positivity. The most direct sign of the violation is the\nrise of the effective mass as a function of distance. The origin of this\nphenomenon lies in the quenched character of the auxiliary field $g$ used to\nimplement lattice gauge fixing, and is similar to quenched QCD in this respect.\nThis is best studied using the PJLZ formalism, leading to a class of covariant\ngauges similar to the one-parameter class of covariant gauges commonly used in\ncontinuum gauge theories. Soluble models are used to illustrate the origin of\nthe violation of spectral positivity. The phase diagram of the lattice theory,\nas a function of the gauge coupling $\\beta$ and the gauge-fixing parameter\n$\\alpha$, is similar to that of the unquenched theory, a Higgs model of a type\nfirst studied by Fradkin and Shenker. The gluon propagator is interpreted as\nyielding bound states in the confined phase, and a mixture of fundamental\nparticles in the Higgs phase, but lattice simulation shows the two phases are\nconnected. Gauge field propagators from the simulation of an SU(2) lattice\ngauge theory on a $20^4$ lattice are well described by a quenched mass-mixing\nmodel. The mass of the lightest state, which we interpret as the gluon mass,\nappears to be independent of $\\alpha$ for sufficiently large $\\alpha$.",
        "positive": "Staggered fermions, zero modes, and flavor-singlet mesons: We examine the taste structure of eigenvectors of the staggered-fermion Dirac\noperator. We derive a set of conditions on the eigenvectors of modes with small\neigenvalues (near-zero modes), such that staggered fermions reproduce the 't\nHooft vertex in the continuum limit. We also show that, assuming these\nconditions, the correlators of flavor-singlet mesons are free of contributions\nsingular in $1/m$, where $m$ is the quark mass. This conclusion holds also when\na single flavor of sea quark is represented by the fourth root of the\nstaggered-fermion determinant. We then test numerically, using the HISQ action,\nwhether these conditions hold on realistic lattice gauge fields. We find that\nthe needed structure does indeed emerge."
    },
    {
        "anchor": "Improved real-time dynamics from imaginary frequency lattice simulations: The computation of real-time properties, such as transport coefficients or\nbound state spectra of strongly interacting quantum fields in thermal\nequilibrium is a pressing matter. Since the sign problem prevents a direct\nevaluation of these quantities, lattice data needs to be analytically continued\nfrom the Euclidean domain of the simulation to Minkowski time, in general an\nill-posed inverse problem. Here we report on a novel approach to improve the\ndetermination of real-time information in the form of spectral functions by\nsetting up a simulation prescription in imaginary frequencies. By carefully\ndistinguishing between initial conditions and quantum dynamics one obtains\naccess to correlation functions also outside the conventional Matsubara\nfrequencies. In particular the range between $\\omega_0$ and $\\omega_1=2\\pi T$,\nwhich is most relevant for the inverse problem may be more highly resolved. In\ncombination with the fact that in imaginary frequencies the kernel of the\ninverse problem is not an exponential but only a rational function we observe\nsignificant improvements in the reconstruction of spectral functions,\ndemonstrated in a simple 0+1 dimensional scalar field theory toy model.",
        "positive": "Neutron electric polarizability: We use the background field method to extract the \"connected\" piece of the\nneutron electric polarizability. We present results for quenched simulations\nusing both clover and Wilson fermions and discuss our experience in extracting\nthe mass shifts and the challenges we encountered when we lowered the quark\nmass. For the neutron we find that as the pion mass is lowered below $500\\MeV$,\nthe polarizability starts rising in agreement with predictions from chiral\nperturbation theory. For our lowest pion mass, $m_\\pi=320\\MeV$, we find that\n$\\alpha_n = 3.8(1.3)\\times 10^{-4}\\fm^3$, which is still only one third of the\nexperimental value. We also present results for the neutral pion; we find that\nits polarizability turns negative for pion masses smaller than $500\\MeV$ which\nis puzzling."
    },
    {
        "anchor": "Trouble shooting for covariance fitting in highly correlated data: We report a possible solution to the trouble that the covariance fitting\nfails when the data is highly correlated and the covariance matrix has small\neigenvalues. As an example, we choose the data analysis of highly correlated\n$B_K$ data on the basis of the SU(2) staggered chiral perturbation theory.\nBasically, the essence of the problem is that we do not have an accurate\nfitting function so that we cannot fit the highly correlated and precise data.\nWhen some eigenvalues of the covariance matrix are small, even a tiny error of\nfitting function can produce large chi-square and spoil the fitting procedure.\nWe have applied a number of prescriptions available in the market such as\ndiagonal approximation and cutoff method. In addition, we present a new method,\nthe eigenmode shift method which fine-tunes the fitting function while keeping\nthe covariance matrix untouched.",
        "positive": "Towards a determination of Csw using Numerical Stochastic Perturbation\n  Theory (NSPT): We outline a strategy to compute the second-loop contribution to the Csw\ncoefficient of the Sheikoleslami-Wohlert-Wilson fermion action by means of\nNSPT. We also present preliminary results for higher-order integrators for the\nLangevin evolution within NSPT. At fixed numerical accuracy, these integrators\nconsiderably reduce the required computer-time."
    },
    {
        "anchor": "Towards high partial waves in lattice QCD with a dumbbell-like operator: An extended two-hadron operator is developed to extract the spectra of\nirreducible representations (irreps) in the finite volume. The irreps of the\ngroup for the finite volume system are projected using a coordinate-space\noperator. The correlation function of this operator is computationally\nefficient to extract lattice spectra of the specific irrep. In particular, this\nnew formulation only requires propagators to be computed from two distinct\nsource locations, at fixed spatial separation. We perform a proof-of-principle\nstudy on a $24^3 \\times 48$ lattice volume with $m_\\pi\\approx 900$ MeV by\nisolating various spectra of the $\\pi\\pi$ system with isospin-2 including a\nrange of total momenta and irreps. By applying the L\\\"uscher formalism, the\nphase shifts of $S$-, $D$- and $G$-wave $\\pi\\pi$ scattering with isospin-2 are\nextracted from the spectra.",
        "positive": "An application of the variational analysis to calculate the meson\n  spectral functions: We present a new method to calculate meson spectral functions (SPFs) on the\nlattice based on a variational method. Because, on a finite volume lattice, the\nmeson SPFs have discrete spectra only, a suitable way to extract such discrete\nsignals is needed. Using a variational method, we can calculate several\ndiscrete quantities such as the position and the area of spectral peaks for\nlow-lying states. Moreover data accuracy can be improved by increasing the\nnumber of basis functions. In this report, we first confirm our method in the\nfree quark case and show that our method works well. Then, we apply the method\nto a quenched lattice QCD simulation and calculate the charmonium SPFs for S\nand P-waves at zero temperature. Our results for the ground state are well\nconsistent with the position and the area of the lowest peaks of charmonium\nSPFs calculated by the conventional maximum entropy method. For first excited\nstates, the signals may be reliablly extracted with our method because the\ncharmonium mass converges to a value close to the experimental one when the\nnumber of basis functions is increased. We also investigate the SPFs for S-wave\ncharmonia at below and above $T_c$. Our results suggest that $J/\\psi$ and\n$\\eta_c$ may survive up to 1.4$T_c$."
    },
    {
        "anchor": "Ehrenfest theorems and charge antiscreening in Abelian projected gauge\n  theories: We derive exact relations for SU(2) lattice gauge theory in 3+1 dimensions.\nIn terms of Abelian projection, these are the expectation values of Maxwell\nequations that define a new field strength operator and conserved, dynamic\nelectric currents formed from the charged matter and ghost fields. The effect\nof gauge fixing is calculated, and in the maximally Abelian gauge we find\nantiscreening of U(1) Wilson loop source charges. We discuss the importance of\nthese quantities in the dual superconducting vacuum mechanism of confinement.",
        "positive": "A spectroscopical analysis of the phase diagram of Yang-Mills-Higgs\n  theory: Yang-Mills-Higgs theory, being the standard-model Higgs sector for a suitable\nchoice of gauge and custodial group, offers a rich set of physics. In\nparticular, in some region of its parameter space it has QCD-like behavior,\nwhile in some other region it is Higgs-like. Therefore, it is possible to study\na plethora of phenomena within a single theory. Here, the physics of the\nstandard-model version is studied using lattice gauge theory. To this end, the\nlow-lying spectrum in several different channels is obtained for more than 140\ndifferent sets of bare parameters throughout the phase diagram. The theory\nshows quite different behaviors in the different regions, from almost\nYang-Mills-like to the one of an essentially free gas of massive photons.\nEspecially, not always is the behavior as naively expected."
    },
    {
        "anchor": "Baryon Operators and Baryon Spectroscopy: The issues involved in a determination of the baryon resonance spectrum in\nlattice QCD are discussed. The variational method is introduced and the need to\nconstruct a sufficient basis of interpolating operators is emphasised. The\nconstruction of baryon operators using group-theory techniques is outlined. We\nfind that the use both of quark-field smearing and link-field smearing in the\noperators is essential firstly to reduce the coupling of operators to\nhigh-frequency modes and secondly to reduce the gauge-field fluctuations in\ncorrelators. We conclude with a status report of our current investigation of\nbaryon spectroscopy.",
        "positive": "I=3/2 nucleon-pion scattering and the Delta(1232) resonance on 2+1\n  flavor CLS ensembles using the stochastic LapH method: Calculations of the elastic $I=\\frac{3}{2}$ nucleon-pion scattering phase\nshifts on two lattice QCD ensembles with $m_\\pi=200\\mathrm{MeV}$ and\n$280\\mathrm{MeV}$ are presented. The ensembles both employ $N_\\mathrm{f} = 2+1$\nWilson clover fermions. We determine the $\\Delta(1232)$ resonance parameters\nfrom a finite volume scattering analysis. In one study the single partial wave\nsimplification is employed to compute the $p$-wave amplitude while in the other\nwe treat the partial wave mixing between $s$- and $p$-wave contributions.\nFitting our data to a Breit-Wigner resonance model we find $m_\\Delta/m_\\pi =\n7.13(9)$ and $4.75(5)$ on the two ensembles respectively, showing that for a\nlighter quark mass the resonance mass moves from near the $N\\pi$ threshold to\nnear the $N\\pi\\pi$ threshold, in agreement with experiment."
    },
    {
        "anchor": "Chiral Nonanalytic Behaviour: The Edinburgh Plot: The Edinburgh Plot is a scale independent way of presenting lattice QCD\ncalculations over a wide range of quark masses. In this sense it is appealing\nas an indicator of how the approach to physical quark masses is progressing.\nThe difficulty remains that even the most state of the art calculations are\nstill at quark masses that are too heavy to apply dimensionally-regulated\nchiral perturbation theory. We present a method allowing predictions of the\nbehaviour of the Edinburgh plot, in both the continuum, and on the lattice.",
        "positive": "Percolating cluster of center vortices and confinement: We study the role of percolating clusters of center vortices in\nconfigurations of an Ising gauge theory in 3D. It is known that low energy\nfeatures of gauge theories can be described in terms of an ``effective string\npicture'', and that confinement properties are associated with topologically\nnon-trivial configurations. We focus our attention upon percolating clusters of\ncenter vortices, and present numerical evidence for the fact that these objects\nplay a preminent role in confinement phenomenon, since their removal sweeps off\nconfinement altogether. Moreover, numerical simulations show that the string\nfluctuations, and in particular the Luescher term, are completely encoded in\nthe percolating cluster."
    },
    {
        "anchor": "Dynamic relaxation of SU(2) lattice gauge theory in (3+1) dimensions: We investigate the dynamic relaxation for SU(2) gauge theory at finite\ntemperatures in (3+1) dimensions. Using the Hybrid Monte Carlo algorithm, we\nexamine the time dependence of the system in the short-time regime. Starting\nfrom the ordered state, the critical exponents beta, nu and z are calculated\nfrom the power law behaviour of the Polyakov loop and the cumulant at or near\nthe critical point. The results for the static exponents are in agreement with\nthose obtained from simulations in equilibrium and those of the\nthree-dimensional Ising model. The value for the dynamic critical exponent was\ndetermined with z=2.0(1).",
        "positive": "Interface tension of the 3d 4-state Potts model using the Wang-Landau\n  algorithm: We study the interface tension of the 4-state Potts model in three dimensions\nusing the Wang- Landau algorithm. The interface tension is given by the ratio\nof the partition function with a twisted boundary condition in one direction\nand periodic boundary conditions in all other directions over the partition\nfunction with periodic boundary conditions in all directions. With the\nWang-Landau algorithm we can explicitly calculate both partition functions and\nobtain the result for all temperatures. We find solid numerical evidence for\nperfect wetting. Our algorithm is tested by calculating thermodynamic\nquantities at the phase transition point."
    },
    {
        "anchor": "Gauge Equivariant Neural Networks for 2+1D U(1) Gauge Theory Simulations\n  in Hamiltonian Formulation: Gauge Theory plays a crucial role in many areas in science, including high\nenergy physics, condensed matter physics and quantum information science. In\nquantum simulations of lattice gauge theory, an important step is to construct\na wave function that obeys gauge symmetry. In this paper, we have developed\ngauge equivariant neural network wave function techniques for simulating\ncontinuous-variable quantum lattice gauge theories in the Hamiltonian\nformulation. We have applied the gauge equivariant neural network approach to\nfind the ground state of 2+1-dimensional lattice gauge theory with U(1) gauge\ngroup using variational Monte Carlo. We have benchmarked our approach against\nthe state-of-the-art complex Gaussian wave functions, demonstrating improved\nperformance in the strong coupling regime and comparable results in the weak\ncoupling regime.",
        "positive": "O(a^2) corrections to the one-loop propagator and bilinears of clover\n  fermions with Symanzik improved gluons: We calculate corrections to the fermion propagator and to the Green's\nfunctions of all fermion bilinear operators of the form $\\bar\\Psi \\Gamma \\Psi$,\nto one-loop in perturbation theory.\n  We employ the Wilson/clover action for fermions and a family of Symanzik\nimproved actions for gluons.\n  The novel aspect of our calculations is that they are carried out to second\norder in the lattice spacing, $O(a^2)$. Consequently, they have addressed a\nnumber of new issues, most notably the appearance of loop integrands with\nstrong IR divergences (convergent only beyond 6 dimensions). Such integrands\nare not present in $O(a^1)$ improvement calculations; there, IR divergent terms\nare seen to have the same structure as in the $O(a^0)$ case, by virtue of\nparity under integration, and they can thus be handled by well-known\ntechniques. We explain how to correctly extract the full $O(a^2)$ dependence;\nin fact, our method is generalizable to any order in $a$.\n  The $O(a^2)$ corrections to the quark propagator and Green's functions\ncomputed in this paper are useful to improve the nonperturbative RI-MOM\ndetermination of renormalization constants for quark bilinear operators.\n  Our results depend on a large number of parameters: coupling constant, number\nof colors, lattice spacing, external momentum, clover parameter, Symanzik\ncoefficients, gauge parameter. To make these results most easily accessible to\nthe reader, we have included them in the distribution package of this paper, as\nan ASCII file named: Oa2results.m ; the file is best perused as Mathematica\ninput."
    },
    {
        "anchor": "Low-lying Lambda Baryons from the Lattice: In a lattice QCD calculation with two light dynamical Chirally Improved (CI)\nquarks we determine ground state and some excited state masses in all four\nLambda baryon channels 1/2^\\pm and 3/2^\\pm. We perform an infinite volume\nextrapolation and confirm the widely discussed Lambda(1405). We also analyze\nthe amount of octet-singlet mixing, which is helpful in comparing states with\nthe quark model.",
        "positive": "Finite volume effects near the chiral crossover: The effect of a finite volume presents itself both in heavy ion experiments\nas well as in recent model calculations. The magnitude is sensitive to the\nproximity of a nearby critical point. We calculate the finite volume effects at\nfinite temperature in continuum QCD using lattice simulations and set the focus\non the vicinity of the chiral crossover. We investigate the impact of finite\nvolumes at zero and small chemical potentials on the QCD transition through the\nchiral observables."
    },
    {
        "anchor": "More about orbitally excited hadrons from lattice QCD: This is a second paper describing the calculation of spectroscopy for\norbitally excited states from lattice simulations of Quantum Chromodynamics.\nNew features include higher statistics for P-wave systems and first results for\nthe spectroscopy of D-wave mesons and baryons, for relatively heavy quark\nmasses. We parameterize the Coulomb gauge wave functions for P-wave and D-wave\nsystems and compare them to those of their corresponding S-wave states.",
        "positive": "Loop Approach to Lattice Gauge Theories: We solve the Gauss law and the corresponding Mandelstam constraints in the\nloop Hilbert space ${\\cal H}^{L}$ using the prepotential formulation of $(d+1)$\ndimensional SU(2) lattice gauge theory. The resulting orthonormal and complete\nloop basis, explicitly constructed in terms of the $d(2d-1)$ prepotential\nintertwining operators, is used to transcribe the gauge dynamics directly in\n${\\cal H}^{L}$ without any redundant gauge and loop degrees of freedom. Using\ngeneralized Wigner-Eckart theorem and Biedenharn -Elliot identity in ${\\cal\nH}^L$, we show that the loop dynamics for pure SU(2) lattice gauge theory in\narbitrary dimension, is given by the real symmetric $3nj$ symbols of first kind\n(e.g., n=6, 10 for d=2, 3 respectively). The corresponding \"ribbon diagrams\"\nrepresenting SU(2) loop dynamics are constructed. The prepotential techniques\nare trivially extended to include fundamental matter fields leading to a\ndescription in terms of loops and strings. The SU(N) gauge group is briefly\ndiscussed."
    },
    {
        "anchor": "Confinement-Higgs Phase Crossover as a Lattice Artifact in 1+1\n  Dimensions: We examine the phase structure of massive Yang-Mills theory in 1+1\ndimensions. This theory is equivalent to a gauged principal chiral sigma model.\nIt has been previously shown that the gauged theory has only a confined phase,\nand no Higgs phase in the continuum, and at infinite volume. There are no\nmassive gluons, but only hadron-like bound states of sigma-model particles. The\nreason is that the gluon mass diverges, being proportional to the two-point\ncorrelation function of the renormalized field of the sigma model at $x=0$. We\nuse exact large-$N$ results to show that after introducing a lattice\nregularization and typical values of the coupling constants used in Monte Carlo\nsimulations, the gluon mass becomes finite, and even sometimes small. A smooth\ncrossover into a Higgs phase can then appear. For small volumes and large $N$,\nwe find an analytic expression for the gluon mass, which depends on the\ncoupling constants and the volume. We argue that this Higgs phase is\nqualitatively similar to the one observed in lattice computations at $N=2$.",
        "positive": "Scalar Field Theory with a Non-Standard Potential: We study the phase structure of a 4D complex scalar field theory with a\npotential V(Phi) = | Lambda^3 / Phi - Lambda Phi |^2 at zero and at finite\ntemperature. The model is analyzed by mean field and Monte Carlo methods. At\nzero temperature the theory falls in the universality class of the 4D Ising\nmodel when varying Lambda. The situation is less clear-cut for variations\nw.r.t. Lambda at large temperatures and variations w.r.t. temperature at a\ngiven value of Lambda. We observe temperature independence of the mass of the\nfirst excitation."
    },
    {
        "anchor": "Generalised parton distributions from the off-forward Compton amplitude\n  in lattice QCD: We determine the properties of generalised parton distributions (GPDs) from a\nlattice QCD calculation of the off-forward Compton amplitude (OFCA). By\nextending the Feynman-Hellmann relation to second-order matrix elements at\noff-forward kinematics, this amplitude can be calculated from lattice\npropagators computed in the presence of a background field. Using an operator\nproduct expansion, we show that the deeply-virtual part of the OFCA can be\nparameterised in terms of the low-order Mellin moments of the GPDs. We apply\nthis formalism to a numerical investigation for zero-skewness kinematics at two\nvalues of the soft momentum transfer, $t = -1.1, -2.2 \\;\\text{GeV}^2$, and a\npion mass of $m_{\\pi}\\approx 470\\;\\text{MeV}$. The form factors of the lowest\ntwo moments of the nucleon GPDs are determined, including the first lattice QCD\ndetermination of the $n=4$ moments. Hence we demonstrate the viability of this\nmethod to calculate the OFCA from first principles, and thereby provide novel\nconstraint on the $x$- and $t$-dependence of GPDs.",
        "positive": "$X(3872)$ Relevant $D\\bar{D}^*$ Scattering in $N_f=2$ Lattice QCD: We study the $S$-wave $D\\bar{D}^*(I=0)$ scattering at four different pion\nmasses $m_\\pi$ ranging from 250 MeV to 417 MeV from $N_f=2$ lattice QCD. A\nbound state near the $D\\bar{D}^*$ threshold likely exists even after\nconsidering the possible left-hand cut effect due to the one pion exchange\ninteraction. At $m_\\pi\\approx 417$ MeV where the effective range expansion is\nvalid, the compositeness of the bound state is $X\\approx 1$ and indicates a\npredominant $D\\bar{D}^*$ component. This state may correspond to $X(3872)$. On\nthe other hand, our results of the finite volume energies also hint at the\nexistence of a $1^{++}$ resonance below 4.0 GeV with a width around 60 MeV."
    },
    {
        "anchor": "Improved Lattice Renormalization Group Techniques: We compute the bare step-scaling function $s_b$ for SU(3) lattice gauge\ntheory with $N_f = 12$ massless fundamental fermions, using the\nnon-perturbative Wilson-flow-optimized Monte Carlo Renormalization Group\ntwo-lattice matching technique. We use a short Wilson flow to approach the\nrenormalized trajectory before beginning RG blocking steps. By optimizing the\nlength of the Wilson flow, we are able to determine an $s_b$ corresponding to a\nunique discrete $\\beta$ function, after a few blocking steps. We carry out this\nstudy using new ensembles of 12-flavor gauge configurations generated with\nexactly massless fermions, using volumes up to $32^4$. The results are\nconsistent with the existence of an infrared fixed point (IRFP) for all\ninvestigated lattice volumes and number of blocking steps. We also compare\ndifferent renormalization schemes, each of which indicates an IRFP at a\nslightly different value of the bare coupling, as expected for an IR-conformal\ntheory.",
        "positive": "Vacuum alignment and lattice artifacts: staggered fermions: In confining lattice gauge theories in which part of the flavor group is\ncoupled weakly to additional gauge fields, both the dynamics of the weak gauge\nfields as well as lattice artifacts may have non-trivial effects on the\norientation of the vacuum in flavor space. Here we discuss this issue for\nlattice gauge theories employing staggered fermions. Staggered fermions break\nflavor symmetries to a much smaller group on the lattice, and orientations in\nflavor space that are equivalent in the continuum may be distinct on the\nlattice. Assuming universality, we show that in the continuum limit the weakly\ngauged flavor symmetries are always vector-like, disproving a recent claim in\nthe literature."
    },
    {
        "anchor": "The Kaon B-parameter from Two-Flavour Dynamical Domain Wall Fermions: We report on the calculation of the kaon B-parameter using two dynamical\nflavours of domain wall fermions. Our analysis is based on three ensembles of\nconfigurations, each consisting of about 5,000 HMC trajectories, with a lattice\nspacing of approximately 1.7 GeV for 16^3x32 lattices; dynamical quark masses\nrange from approximately the strange quark mass to half of that. Both\ndegenerate and non-degenerate quark masses are used for the kaons.",
        "positive": "The static force from generalized Wilson loops: Recently a method to compute the static force with lattice gauge theory using\nan insertion of a chromoelectric field into a Wilson loop was proposed. We\nexplore this method using the multilevel algorithm and discuss the\nrenormalization of the chromoelectric field on the lattice."
    },
    {
        "anchor": "Chiral gauge theory at the boundary between topological phases: I demonstrate how chiral fermions with an exact gauge symmetry can appear on\nthe d-dimensional boundary of a finite volume (d+1)-dimensional manifold,\nwithout any light mirror partners. The condition for the d-dimensional boundary\ntheory to be local is that gauge anomalies cancel and that the volume be large.\nThis can likely be achieved on a lattice and provides a new paradigm for the\nlattice regularization of chiral gauge theories.",
        "positive": "Lattice continuum-limit study of nucleon quasi-PDFs: The quasi-PDF approach provides a path to computing parton distribution\nfunctions (PDFs) using lattice QCD. This approach requires matrix elements of a\npower-divergent operator in a nucleon at high momentum and one generically\nexpects discretization effects starting at first order in the lattice spacing\n$a$. Therefore, it is important to demonstrate that the continuum limit can be\nreliably taken and to understand the size and shape of lattice artifacts. In\nthis work, we report a calculation of isovector unpolarized and helicity PDFs\nusing lattice ensembles with $N_f=2+1+1$ Wilson twisted mass fermions, a pion\nmass of approximately 370 MeV, and three different lattice spacings. Our\nresults show a significant dependence on $a$, and the continuum extrapolation\nproduces a better agreement with phenomenology. The latter is particularly true\nfor the antiquark distribution at small momentum fraction $x$, where the\nextrapolation changes its sign."
    },
    {
        "anchor": "The Pseudoscalar Decay Constant: We discuss insights that may be drawn from our recent 2 flavour\nO(a)--improved Wilson quark simulations. We discuss the evidence of the onset\nof chiral logarithms in the pion decay constant. An overview is given of\ncurrent extrapolation methods and a modification of chiral perturbation theory\nis presented as an approach for sensibly extrapolating to the physical quark\nmasses.",
        "positive": "Non perturbative determination of the running coupling constant in\n  quenched SU(2): Through a finite size renormalization group technique we calculate the\nrunning coupling constant for quenched SU(2) with a few percent error over a\nrange of energy varying by a factor thirty. The definition is based on ratio of\ncorrelations of Polyakov loops with twisted boundary conditions. The\nextrapolation to the continuum limit is governed by corrections due to lattice\nartifacts which are proportional to the square of the lattice spacing and\nappears rather smooth."
    },
    {
        "anchor": "A new description of lattice Yang-Mils theory and non-Abelian monopoles\n  as the quark confiner: We propose a new description of the SU(N) Yang-Mills theory on a lattice,\nwhich enables one to explain quark confinement based on the dual\nsuperconductivity picture in a gauge independent way. This is because we can\ndefine gauge-invariant magnetic monopoles which are inherent in the Wilson loop\noperator. For SU(3) there are two options: the minimal option with a single\ntype of non-Abelian magnetic monopole characterized by the maximal stability\nsubgroup $\\tilde{H}=U(2)=SU(2)\\times U(1)$, and the maximal one with two types\nof Abelian magnetic monopoles characterized by the maximal torus subgroup\n$\\tilde{H}=U(1)\\times U(1)$. The maximal option corresponds to a gauge\nindependent reformulation of the Abelian projection represented by the\nconventional MAG. In the minimal option, we have successfully performed the\nnumerical simulation of the SU(3) Yang-Mills theory on a lattice. We give\npreliminary numerical results showing the dominance of the non-Abelian magnetic\nmonopole in the string tension obtained from the Wilson loop in the fundamental\nrepresentation, and the infrared dominance of a decomposed field variable for\ncorrelation functions after demonstrating the preservation of color symmetry\nwhich was explicitly broken by the conventional MAG.",
        "positive": "Improved Lattice Radial Quantization: Lattice radial quantization was proposed in a recent paper by Brower, Fleming\nand Neuberger[1] as a nonperturbative method especially suited to numerically\nsolve Euclidean conformal field theories. The lessons learned from the lattice\nradial quantization of the 3D Ising model on a longitudinal cylinder with 2D\nIcosahedral cross-section suggested the need for an improved discretization. We\nconsider here the use of the Finite Element Methods(FEM) to descretize the\nuniversally-equivalent $\\phi^4$ Lagrangian on $\\mathbb R \\times \\mathbb S^2$.\nIt is argued that this lattice regularization will approach the exact conformal\ntheory at the Wilson-Fisher fixed point in the continuum. Numerical tests are\nunderway to support this conjecture."
    },
    {
        "anchor": "External Fields and Color Confinement: U(1), SU(2), and SU(3) lattice gauge theories in presence of external fields\nare investigated both in (3+1) and (2+1) dimensions. The free energy of gauge\nsystems has been measured. While the phase transition in compact U(1) is not\ninfluenced by the strength of an external constant magnetic field, the\ndeconfinement temperature for SU(2) and SU(3) gauge systems in a constant\nabelian chromomagnetic field decreases when the strength of the applied field\nincreases. The dependence of the deconfinement temperature on the strength of\nan external constant chromomagnetic field seems to be a peculiar feature of non\nabelian gauge theories.",
        "positive": "Simulations in Early Universe Theory: We give an impression of the type of results that have been obtained with\nnumerical lattice simulations of field theory in the early universe."
    },
    {
        "anchor": "A Ginzburg-Landau Analysis of the Colour Electric Flux Tube: In a simulation of SU(2) gauge theory we investigate, after maximal Abelian\nprojection, the dual Maxwell equations for colour field and monopole current\ndistributions around a static quark-antiquark pair Q_ Q in vacuo. Within the\ndual superconductor picture we carry out a Ginzburg-Landau type analysis of the\nflux tube profile. As a result we can determine the coherence length of the GL\nwave function related to the monopole condensate, xi = .25(3) fm, to be\ncompared to the penetration length, lambda = >.15(2) fm (scaled with the string\ntension).",
        "positive": "The gluino-glue particle and finite size effects in supersymmetric\n  Yang-Mills theory: The spectrum of particles in supersymmetric Yang-Mills theory is expected to\ncontain a spin 1/2 bound state of gluons and gluinos, the gluino-glue particle.\nWe study the mass of this particle in softly broken supersymmetric Yang-Mills\ntheory on a lattice by means of numerical simulations. The main focus is the\nestimation of finite size effects. We extrapolate the mass first to the\ninfinite volume and then to the limit of a vanishing gluino mass. The results\nindicate that finite size effects are tolerable on lattices of moderate size,\nand that remaining deviations from supersymmetry are probably due to finite\nlattice spacing effects."
    },
    {
        "anchor": "1-Loop improved lattice action for the nonlinear sigma-model: In this paper we show the Wilson effective action for the 2-dimensional\nO(N+1)-symmetric lattice nonlinear sigma-model computed in the 1-loop\napproximation for the nonlinear choice of blockspin $\\Phi(x)$, $\\Phi(x)=\n\\Cav\\phi(x)/{|\\Cav\\phi(x)|}$,where $\\Cav$ is averaging of the fundamental field\n$\\phi(z)$ over a square $x$ of side $\\tilde a$.\n  The result for $S_{eff}$ is composed of the classical perfect action with a\nrenormalized coupling constant $\\beta_{eff}$, an augmented contribution from a\nJacobian, and further genuine 1-loop correction terms. Our result extends\nPolyakov's calculation which had furnished those contributions to the effective\naction which are of order $\\ln \\tilde a /a$, where $a$ is the lattice spacing\nof the fundamental lattice. An analytic approximation for the background field\nwhich enters the classical perfect action will be presented elsewhere.",
        "positive": "Logarithmic Corrections to Scaling in the Two Dimensional $XY$--Model: By expressing thermodynamic functions in terms of the edge and density of\nLee--Yang zeroes, we relate the scaling behaviour of the specific heat to that\nof the zero field magnetic susceptibility in the thermodynamic limit of the\n$XY$--model in two dimensions. Assuming that finite--size scaling holds, we\nshow that the conventional Kosterlitz--Thouless scaling predictions for these\nthermodynamic functions are not mutually compatable unless they are modified by\nmultiplicative logarithmic corrections. We identify these logarithmic\ncorrections analytically in the case of the specific heat and numerically in\nthe case of the susceptibility. The techniques presented here are general and\ncan be used to check the compatibility of scaling behaviour of odd and even\nthermodynamic functions in other models too."
    },
    {
        "anchor": "The non-perturbative part of the plaquette in quenched QCD: We define the non-perturbative part of a quantity as the difference between\nits numerical value and the perturbative series truncated by dropping the order\nof minimal contribution and the higher orders. For the anharmonic oscillator,\nthe double-well potential and the single plaquette gauge theory, the\nnon-perturbative part can be parametrized as A (lambda)^B exp{-C/lambda} and\nthe coefficients can be calculated analytically. For lattice QCD in the\nquenched approximation, the perturbative series for the average plaquette is\ndominated at low order by a singularity in the complex coupling plane and the\nasymptotic behavior can only be reached by using extrapolations of the existing\nseries. We discuss two extrapolations that provide a consistent description of\nthe series up to order 20-25. These extrapolations favor the idea that the\nnon-perturbative part scales like (a/r_0)^4 with a/r_0 defined with the force\nmethod. We discuss the large uncertainties associated with this statement. We\npropose a parametrization of ln((a/r_0)) as the two-loop universal terms plus a\nconstant and exponential corrections. These corrections are consistent with\na_{1-loop}^2 and play an important role when beta<6. We briefly discuss the\npossibility of calculating them semi-classically at large beta.",
        "positive": "Learning Trivializing Gradient Flows for Lattice Gauge Theories: We propose a unifying approach that starts from the perturbative construction\nof trivializing maps by L\\\"uscher and then improves on it by learning. The\nresulting continuous normalizing flow model can be implemented using common\ntools of lattice field theory and requires several orders of magnitude fewer\nparameters than any existing machine learning approach. Specifically, our model\ncan achieve competitive performance with as few as 14 parameters while existing\ndeep-learning models have around 1 million parameters for $SU(3)$ Yang--Mills\ntheory on a $16^2$ lattice. This has obvious consequences for training speed\nand interpretability. It also provides a plausible path for scaling\nmachine-learning approaches toward realistic theories."
    },
    {
        "anchor": "Putting centre dominance under the microscope: We make various short points on the phenomenon of centre dominance in SU(2).\nThe Z(2) dominance seen in Wilson loops is related to the loop distribution and\nto half-odd-integer representations of the group. The distributions also make\nit clear that, in this picture, the requirement of vortices for confinement is\nessentially trivial. We confirm that the same effect appears in the positive\nplaquette model. The simple random vortex picture is shown to give a\nsubstantial fraction of the string tension.",
        "positive": "Fermions at Finite Density in (2+1)d with Sign-Optimized Manifolds: We present Monte Carlo calculations of the thermodynamics of the (2+1)\ndimensional Thirring model at finite density. We bypass the sign problem by\ndeforming the domain of integration of the path integral into complex space in\nsuch a way as to maximize the average sign within a parameterized family of\nmanifolds. We present results for lattice sizes up to $10^3$ and we find that\nat high densities and/or temperatures the chiral condensate is abruptly\nreduced."
    },
    {
        "anchor": "Decorrelating the topology in full QCD: We investigate the performance of the hybrid Monte Carlo algorithm in\nupdating non-trivial global topological structures. We find that the hybrid\nMonte Carlo algorithm has serious problems decorrelating the global topological\ncharge. This represents a warning which must be seriously considered when\nsimulating full QCD, regardless of the number and type of fermions, with this\nor any similar algorithm. Simulated tempering is examined as a means of\naccelerating the decorrelation.",
        "positive": "Chiral Fermions on the Lattice: In the last century the non-perturbative regularization of chiral fermions\nwas a long-standing problem. We review how this problem was finally overcome by\nthe formulation of a modified but exact form of chiral symmetry on the lattice.\nThis also provides a sound definition of the topological charge of lattice\ngauge configurations. We illustrate a variety of applications to QCD in the p-,\nthe epsilon- and the delta-regime, where simulation results can now be related\nto Random Matrix Theory and Chiral Perturbation Theory. The latter contains Low\nEnergy Constants as free parameters, and we comment on their evaluation from\nfirst principles of QCD."
    },
    {
        "anchor": "First Physics Results at the Physical Pion Mass from $N_f = 2$ Wilson\n  Twisted Mass Fermions at Maximal Twist: We present physics results from simulations of QCD using $N_f = 2$ dynamical\nWilson twisted mass fermions at the physical value of the pion mass. These\nsimulations were enabled by the addition of the clover term to the twisted mass\nquark action. We show evidence that compared to previous simulations without\nthis term, the pion mass splitting due to isospin breaking is almost completely\neliminated. Using this new action, we compute the masses and decay constants of\npseudoscalar mesons involving the dynamical up and down as well as valence\nstrange and charm quarks at one value of the lattice spacing, $a \\approx 0.09$\nfm. Further, we determine renormalized quark masses as well as their\nscale-independent ratios, in excellent agreement with other lattice\ndeterminations in the continuum limit. In the baryon sector, we show that the\nnucleon mass is compatible with its physical value and that the masses of the\n$\\Delta$ baryons do not show any sign of isospin breaking. Finally, we compute\nthe electron, muon and tau lepton anomalous magnetic moments and show the\nresults to be consistent with extrapolations of older ETMC data to the\ncontinuum and physical pion mass limits. We mostly find remarkably good\nagreement with phenomenology, even though we cannot take the continuum and\nthermodynamic limits.",
        "positive": "Numerical analyses of N=2 supersymmetric quantum mechanics with cyclic\n  Leibniz rule on lattice: We study a cyclic Leibniz rule, which provides a systematic approach to\nlattice supersymmetry, using a numerical method with a transfer matrix. The\ncomputation is carried out in N=2 supersymmetric quantum mechanics with the\nphi^6-interaction for weak and strong couplings. The computed energy spectra\nand supersymmetric Ward-Takahashi identities are compared with those obtained\nfrom another lattice action. We find that a model with the cyclic Leibniz rule\nbehaves similarly to the continuum theory compared with the other lattice\naction."
    },
    {
        "anchor": "Thermodynamic Study for Conformal Phase in Large Nf Gauge Theory: We investigate the chiral phase transition at finite temperature (T) in\ncolour SU(3) Quantum Chromodynamics (QCD) with six species of fermions (Nf = 6)\nin the fundamental representation. The simulations have been performed by using\nlattice QCD with improved staggered fermions. The critical couplings (bc) for\nthe chiral phase transition are observed for several temporal extensions Nt,\nand the two-loop asymptotic scaling of the dimensionless ratio Tc/Lambda_L\n(Lambda_L = Lattice Lambda-parameter) is found to be achieved for Nt >= 6.\nFurther, we collect bc at Nf = 0 (quenched), and Nf = 4 at a fixed Nt = 6 as\nwell as Nf = 8 at Nt = 6 and 12, the latter relying on our earlier study. The\nresults are consistent with enhanced fermionic screening at larger Nf. The\nratio Tc/Lambda_L depends very mildly on Nf in the Nf = 0-4 region, begins\nincreasing at Nf = 6, and significantly grows up at Nf = 8, as Nf reaches to\nthe edge of the conformal window. We discuss the interrelation of the results\nwith preconformal dynamics in the light of a functional renormalization group\nanalysis.",
        "positive": "A novel approach for computing glueball masses and matrix elements in\n  Yang-Mills theories on the lattice: We make use of the global symmetries of the Yang-Mills theory on the lattice\nto design a new computational strategy for extracting glueball masses and\nmatrix elements which achieves an exponential reduction of the statistical\nerror with respect to standard techniques. By generalizing our previous work on\nthe parity symmetry, the partition function of the theory is decomposed into a\nsum of path integrals each giving the contribution from multiplets of states\nwith fixed quantum numbers associated to parity, charge conjugation,\ntranslations, rotations and central conjugations Z_N^3. Ratios of path\nintegrals and correlation functions can then be computed with a multi-level\nMonte Carlo integration scheme whose numerical cost, at a fixed statistical\nprecision and at asymptotically large times, increases power-like with the time\nextent of the lattice. The strategy is implemented for the SU(3) Yang--Mills\ntheory, and a full-fledged computation of the mass and multiplicity of the\nlightest glueball with vacuum quantum numbers is carried out at a lattice\nspacing of 0.17 fm."
    },
    {
        "anchor": "Real-Time Dynamics at Large $N$: The large-$N$ limit of $O(N)$-symmetric bosonic field theories, or\n$U(N)$-symmetric fermionic field theories, is amenable to a saddle point\napproximation. As a result, there is a family of closely related algorithms for\nefficient lattice simulations in this limit, even in the presence of fermionic\nor real-time sign problems. These can be used to study quenches, or other\nobservables for which",
        "positive": "SU(3) Yang Mills theory at small distances and fine lattices: We investigate the SU(3) Yang Mills theory at small gradient flow time and at\nshort distances. Lattice spacings down to $a=0.015$ fm are simulated with open\nboundary conditions to allow topology to flow in and out. We study the\nbehaviour of the action density $E(t)$ close to the boundaries, the feasibility\nof the small flow-time expansion and the extraction of the $\\Lambda$-parameter\nfrom the static force at small distances. For the latter, significant\ndeviations from the 4-loop perturbative $\\beta$-function are visible at\n$\\alpha\\approx 0.2\\,$. We still can extrapolate to extract $r_0\\Lambda$."
    },
    {
        "anchor": "Quenched lattice calculation of the vector channel B --> D* l nu decay\n  rate: We calculate, in the continuum limit of quenched lattice QCD, the form factor\nthat enters the decay rate of the semileptonic decay B --> D* l nu. By using\nthe step scaling method (SSM), previously introduced to handle two scale\nproblems in lattice QCD, and by adopting flavor twisted boundary conditions we\nextract F(w) at finite momentum transfer and at the physical values of the\nheavy quark masses. Our results can be used in order to extract the CKM matrix\nelement Vcb by the experimental decay rate without model dependent\nextrapolations. The value of Vcb agrees with the one obtained from the B --> D\nl nu channel and makes us confident that the quenched approximation well\napplies to these transitions.",
        "positive": "Toward an understanding of short distance repulsions among baryons in\n  QCD -- NBS wave functions and operator product expansion --: We report on our recent attempts to determine the short distance behaviors of\ngeneral 2-baryon and 3-baryon forces, which are defined from the\nNambu-Bethe-Salpeter(NBS) wave function, by using the operator product\nexpansion and a renormalization group analysis in QCD. We have found that the\nrepulsion at short distance increases as the number of valence quarks increases\nor when the number of different flavors involved decreases. This global\ntendency suggests a Pauli suppression principle among quark fields at work."
    },
    {
        "anchor": "Spin-dependent potentials from lattice QCD: The spin-dependent corrections to the static inter-quark potential are\nphenomenologically relevant to describing the fine and hyperfine spin splitting\nof the heavy quarkonium spectra. We investigate these corrections, which are\nrepresented as the field strength correlators on the quark-antiquark source, in\nSU(3) lattice gauge theory. We use the Polyakov loop correlation function as\nthe quark-antiquark source, and by employing the multi-level algorithm, we\nobtain remarkably clean signals for these corrections up to intermediate\ndistances of around 0.6 fm. Our observation suggests several new features of\nthe corrections.",
        "positive": "Comparing lattice Dirac operators in smooth instanton backgrounds: We compare the behavior of different lattice Dirac operators in gauge\nbackgrounds which are lattice discretizations of a classical instanton. In\nparticular we analyze the standard Wilson operator, a chirally improved Dirac\noperator and the overlap operators constructed from these two operators. We\ndiscuss the flow of real eigenvalues as a function of the instanton size. An\nanalysis of the eigenvectors shows that overlap fermions with the Wilson\noperator as input operator have difficulties with reproducing the continuum\nzero mode already for moderately small instantons. This problem is greatly\nreduced when using the chirally improved operator for the overlap projection."
    },
    {
        "anchor": "On the relevance of center vortices to QCD: In a numerical experiment, we remove center vortices from an ensemble of\nlattice SU(2) gauge configurations. This removal adds short-range disorder.\nNevertheless, we observe long-range order in the modified ensemble: confinement\nis lost and chiral symmetry is restored (together with trivial topology),\nproving that center vortices are responsible for both phenomena. As for the\nAbelian monopoles, they survive but their percolation properties are lost.",
        "positive": "Excited nucleon spectrum with two flavors of dynamical fermions: We compute the spectrum of excited nucleons using the anisotropic Wilson\nlattice with two flavors of dynamical fermions. Using optimized sets of\noperators which transform irreducibly under the octahedral group, matrices of\ncorrelation functions are computed. We apply the variational method to these\nmatrices to extract excited energy eigenstates. We obtain several states for\neach irrep and identify the continuum spin for the lowest-lying states,\nincluding a $J^P={5/2}^-$ state."
    },
    {
        "anchor": "Field Strength Correlators and Gluon Condensates at Finite Temperature\n  from Renormalization Group Smoothing: We summarize recent attempts to extract characteristics of non-perturbative\nvacuum structure from lattice measurements of the gauge invariant field\nstrength correlator. As an alternative to cooling, we propose to apply the\nrenormalization group (RG) smoothing method in lattice studies. For pure SU(2)\ngauge theory we present magnetic and electric correlation lengths and\ncondensates related to various correlators over a temperature range of 0.7\nT_{dec} < T < 1.9 T_{dec}",
        "positive": "Approach to the Continuum Limit of the Quenched Hermitian Wilson-Dirac\n  Operator: We investigate the approach to the continuum limit of the spectrum of the\nHermitian Wilson-Dirac operator in the supercritical mass region for pure gauge\nSU(2) and SU(3) backgrounds. For this we study the spectral flow of the\nHermitian Wilson-Dirac operator in the range $0\\le m\\le 2$. We find that the\nspectrum has a gap for $0 < m \\le m_1$ and that the spectral density at zero,\n$\\rho(0;m)$, is non-zero for $m_1\\le m\\le 2$. We find that $m_1\\to 0$ and, for\n$m \\ne 0, \\rho(0;m)\\to 0$ (exponential in the lattice spacing) as one goes to\nthe continuum limit. We also compute the topological susceptibility and the\nsize distribution of the zero modes. The topological susceptibility scales well\nin the lattice spacing for both SU(2) and SU(3). The size distribution of the\nzero modes does not appear to show a peak at a physical scale."
    },
    {
        "anchor": "The compact Q=2 Abelian Higgs model in the London limit: vortex-monopole\n  chains and the photon propagator: The confining and topological properties of the compact Abelian Higgs model\nwith doubly-charged Higgs field in three space-time dimensions are studied. We\nconsider the London limit of the model. We show that the monopoles are forming\nchain-like structures (kept together by ANO vortices) the presence of which is\nessential for getting simultaneously permanent confinement of singly-charged\nparticles and breaking of the string spanned between doubly-charged particles.\nIn the confinement phase the chains are forming percolating clusters while in\nthe deconfinement (Higgs) phase the chains are of finite size. The described\npicture is in close analogy with the synthesis of the Abelian monopole and the\ncenter vortex pictures in confining non--Abelian gauge models. The screening\nproperties of the vacuum are studied by means of the photon propagator in the\nLandau gauge.",
        "positive": "Methods for Pseudoscalar Flavour-Singlet Mesons with Staggered Fermions: We present the first 2+1 flavour lattice QCD calculations of pseudoscalar\nflavour-singlet propagators using improved staggered fermions. We explore the\nrelevant techniques and discuss prospects for the larger scale studies now in\nprogress. The disconnected correlator is shown to have a highly non-Gaussian\ndistribution and reliable estimates of the errors require care."
    },
    {
        "anchor": "Universal and non-universal behavior in Dirac spectra: We have computed ensembles of complete spectra of the staggered Dirac\noperator using four-dimensional SU(2) gauge fields, both in the quenched\napproximation and with dynamical fermions. To identify universal features in\nthe Dirac spectrum, we compare the lattice data with predictions from chiral\nrandom matrix theory for the distribution of the low-lying eigenvalues. Good\nagreement is found up to some limiting energy, the so-called Thouless energy,\nabove which random matrix theory no longer applies. We determine the dependence\nof the Thouless energy on the simulation parameters using the scalar\nsusceptibility and the number variance.",
        "positive": "The critical endpoint in the 2d U(1) gauge-Higgs model at topological\n  angle $\u03b8=\u03c0$: We study 2d U(1) gauge Higgs systems with a $\\theta$-term. For properly\ndiscretizing the topological charge as an integer we introduce a mixed group-\nand algebra-valued discretization (MGA scheme) for the gauge fields, such that\nthe charge conjugation symmetry at $\\theta = \\pi$ is implemented exactly. The\ncomplex action problem from the $\\theta$-term is overcome by exactly mapping\nthe partition sum to a worldline/worldsheet representation. Using Monte Carlo\nsimulation of the worldline/worldsheet representation we study the system at\n$\\theta = \\pi$ and show that as a function of the mass parameter the system\nundergoes a phase transition. Determining the critical exponents from a finite\nsize scaling analysis we show that the transition is in the 2d Ising\nuniversality class. We furthermore study the U(1) gauge Higgs systems at\n$\\theta = \\pi$ also with charge 2 matter fields, where an additional $Z_2$\nsymmetry is expected to alter the phase structure. Our results indicate that\nfor charge 2 a true phase transition is absent and only a rapid crossover\nseparates the large and small mass regions."
    },
    {
        "anchor": "The Higgs Model with a Complex Ghost Pair: A higher derivative term is introduced in the kinetic energy of the Higgs\nLagrangian in the minimal Standard Model. A logically consistent and {\\it\nfinite} field theory is obtained when some excitations of the Higgs field are\nquantized with indefinite metric in the Hilbert space. The Landau ghost\nphenomenon of the conventional triviality problem is replaced by the state\nvectors of a complex ghost pair at a finite mass scale with observable physical\nconsequences. It is shown that the ghost states exhibit unusual resonance\nproperties and correspond to a complex conjugate pair of Pauli-Villars\nregulator masses in the euclidean path integral formulation of the theory. An\nargument is given that microscopic acausality effects associated with the ghost\npair remain undetectable in scattering processes with realistic wave packects,\nand the S-matrix should exhibit unitarity in the observable sector of the\nHilbert space. Part One of Extended UCSD-PTH 92-40",
        "positive": "Generalized parton distributions and structure functions from full\n  lattice QCD: We present here the latest results from the QCDSF collaboration for (moments\nof) structure functions and generalized form factors in full QCD with Nf=2\nO(a)-improved Wilson fermions based on simulations closer to the chiral and\ncontinuum limit."
    },
    {
        "anchor": "Funny business from the large $N_c$ finite temperature crossover: It is well known that the deconfinement transition temperature for $SU(N_c)$\ngauge theory is almost independent of $N_c$, and the transition is first order\nfor $N_c \\ge 3$. In the real world ($N_c=3$, light quarks) it is a crossover\nlocated far away from the pure gauge value. What happens to the transition\ntemperature at fixed fermion mass if the number of fermion flavors is held\nconstant ($N_f=2$) and $N_c$ is varied? There are multiple plausible stories,\nonly one of which appears to be true when the systems are simulated on the\nlattice. I describe the physics issues which surround the question and my\nlattice - based answer to it.",
        "positive": "Finite volume scaling of the electro-magnetic pion form factor in the\n  $\u03b5$ regime: We consider finite volume effects on the electro-magnetic pion form factor\nnear the chiral limit, in the so-called $\\epsilon$ regime. The\npseudoscalar-vector-pseudoscalar three-point function is calculated in the\n$\\epsilon$ expansion of chiral perturbation theory to the next-to-leading\norder. In the $\\epsilon$ regime, finite volume effects are non-perturbatively\nlarge in general. However, we find a way to remove its dominant part, by\ninserting momenta to the correlators, and taking an appropriate ratio of them.\nThe subleading contribution is, then, shown to be perturbatively small, and one\ncan extract the form factor as in a similar way to that in the $p$ regime."
    },
    {
        "anchor": "The QCD equation of state at finite T and \u03bc: We calculate the pressure (p), the energy density (\\epsilon) and the baryon\ndensity (n_B) of QCD at finite temperatures (T) and chemical potentials (\\mu).\nThe recently proposed overlap improving multi-parameter reweighting technique\nis used to determine observables at nonvanishing chemical potentials. Our\nresults are obtained by studying n_f=2+1 dynamical staggered quarks with\nsemi-realistic masses on N_t=4 lattices.",
        "positive": "SU(2) lattice gauge theory on a quantum annealer: Lattice gauge theory is an essential tool for strongly interacting\nnon-Abelian fields, such as those in quantum chromodynamics where lattice\nresults have been of central importance for several decades. Recent studies\nsuggest that quantum computers could extend the reach of lattice gauge theory\nin dramatic ways, but the usefulness of quantum annealing hardware for lattice\ngauge theory has not yet been explored. In this work, we implement SU(2) pure\ngauge theory on a quantum annealer for lattices comprising a few plaquettes in\na row with a periodic boundary condition. These plaquettes are in two spatial\ndimensions and calculations use the Hamiltonian formulation where time is not\ndiscretized. Numerical results are obtained from calculations on D-Wave\nAdvantage hardware for eigenvalues, eigenvectors, vacuum expectation values,\nand time evolution. The success of this initial exploration indicates that the\nquantum annealer might become a useful hardware platform for some aspects of\nlattice gauge theories."
    },
    {
        "anchor": "Large center vortices and confinement in 3D Z(2) gauge theory: We study the role of large clusters of center vortices in producing\nconfinement in 3D Z(2) gauge theory. First, we modify each configuration of a\nMonte Carlo-generated ensemble in the confined phase by removing the largest\ncluster of center vortices, and show that the ensemble thus obtained does not\nconfine. Conversely, we show that removing all of the small clusters of center\nvortices and leaving the largest one only, confinement is preserved, albeit\nwith a string tension significantly smaller than the original one. Remarkably,\nalso the string corrections due to the quantum fluctuations of the confining\nflux tube are preserved by this transformation.",
        "positive": "Towards an interoperable International Lattice Datagrid: The International Lattice Datagrid (ILDG) is a federation of several regional\ngrids. Since most of these grids have reached production level, an increasing\nnumber of lattice scientists start to benefit from this new research\ninfrastructure. The ILDG Middleware Working Group has the task of specifying\nthe ILDG middleware such that interoperability among the different grids is\nachieved. In this paper we will present the architecture of the ILDG middleware\nand describe what has actually been achieved in recent years. Particular focus\nis given to interoperability and security issues. We will conclude with a short\noverview on issues which we plan to address in the near future."
    },
    {
        "anchor": "Effective Field Theories and Quantum Chromodynamics on the Lattice: We give a selection of results on spectrum and decay constants of light and\nheavy-light hadrons. Effective field theories relevant for their lattice\ncalculation, namely non-relativistic QCD (NRQCD) for heavy quarks on the\nlattice and Chiral Perturbation Theory for light quarks, are briefly discussed.",
        "positive": "Forward light-by-light scattering and electromagnetic correction to\n  hadronic vacuum polarization: Lattice QCD calculations of the hadronic vacuum polarization (HVP) have\nreached a precision where the electromagnetic (e.m.) correction can no longer\nbe neglected. This correction is both computationally challenging and hard to\nvalidate, as it leads to ultraviolet (UV) divergences and to sizeable infrared\n(IR) effects associated with the massless photon. While we precisely determine\nthe UV divergence using the operator-product expansion, we propose to introduce\na separation scale $\\Lambda\\sim400\\;$MeV into the internal photon propagator,\nwhereby the calculation splits into a short-distance part, regulated in the UV\nby the lattice and in the IR by the scale $\\Lambda$, and a UV-finite\nlong-distance part to be treated with coordinate-space methods, thereby\navoiding power-law finite-size effects altogether. In order to predict the\nlong-distance part, we express the UV-regulated e.m. correction to the HVP via\nthe forward hadronic light-by-light (HLbL) scattering amplitude and relate the\nlatter via a dispersive sum rule to $\\gamma^*\\gamma^*$ fusion cross-sections.\nHaving tested the relation by reproducing the two-loop QED vacuum polarization\n(VP) from the tree-level $\\gamma^*\\gamma^*\\to e^+e^-$ cross-section, we predict\nthe expected lattice-QCD integrand resulting from the\n$\\gamma^*\\gamma^*\\to\\pi^0$ process."
    },
    {
        "anchor": "Test of the Polyakov Loop Model: We discuss the two point functions for the real and imaginary parts of the\nPolyakov loop in a pure SU(3) gauge theory. The behavior of these correlation\nfunctions in the Polyakov Loop Model is markedly different from that in\nperturbation theory.",
        "positive": "Chiral behaviour of Delta B = 2 and Delta C =2 matrix elements: We investigate the light-quark mass and spatial volume dependence of matrix\nelements of Delta B = 2 and Delta C = 2 four-fermion operators. These operators\nare relevant for Neutral B(s) and D mixing in and beyond the Standard Model. An\nimportant conclusion of this work is that the chiral extrapolations for matrix\nelements of heavy-light meson mixing beyond the Standard Model are more\ncomplicated than that for the Standard Model mixing matrix elements."
    },
    {
        "anchor": "A Transverse Lattice QCD Model for Mesons: This thesis describes work done by me during my tenure as a Ph.D. student at\nthe Centre for High Energy Physics, Indian Institute of Science, Bangalore.\nChapter 1 is a brief introduction to QCD. In Chapter 2, we formulate QCD in the\nlarge-$N_{c}$ and strong transverse coupling limits, and then exactly integrate\nout all the gauge degrees of freedom to obtain the generating functional for\nquark-antiquark bilinears. We study the chiral properties of our limiting\ntheory in Chapter 3, for naive as well as Wilson fermions, and obtain a\nrecursive relation for the chiral condensate. In Chapter 4, we obtain the\nhomogeneous integral equation satisfied by the meson states of our theory.\nComparison of this equation with the corresponding one for the 't~Hooft model\nallows us to infer many physical meson properties. Our results are consistent\nwith phenomenological expectations, and this is the first time that such\nresults have been obtained from $(3+1)$-dim QCD, with only quark and gluon\ndegrees of freedom and no ad hoc model assumptions. Extraction of precise\nvalues requires numerical solution of the integral equation; we have not yet\ncarried that out and we describe our outlook for further investigations at the\nend of Chapter 4. Three appendices supplement our analysis. Our notation and\nconventions are listed in Appendix A. The known results for mesons in the\n't~Hooft model and in strong coupling lattice QCD are rederived, in Appendix B\nand in Appendix C respectively, using the same methodology as followed in the\nthesis. That allows convenient comparison, as well as demonstrates the\nadvantage of our approach over these two well-studied approximations to QCD.",
        "positive": "Landau gauge ghost and gluon propagators in SU(2) lattice gauge theory:\n  Gribov ambiguity revisited: We reinvestigate the problem of Gribov ambiguities within the Landau (or\nLorentz) gauge for the ghost and gluon propagators in pure SU(2) lattice gauge\ntheory. We make use of the full symmetry group of the action taking into\naccount {\\it large}, i.e. non-periodic $\\mathbb{Z}(2)$ gauge transformations\nleaving lattice plaquettes invariant. Enlarging in this way the gauge orbits\nfor any given gauge field configuration the Landau gauge can be fixed at higher\nlocal extrema of the gauge functional in comparison with standard\n(overrelaxation) techniques. This has a clearly visible effect not only for the\nghost propagator at small momenta but also for the gluon propagator, in\ncontrast to the common belief."
    },
    {
        "anchor": "Staggered fermion matrix elements using smeared operators: We investigate the use of two kinds of staggered fermion operators, smeared\nand unsmeared. The smeared operators extend over a $4^4$ hypercube, and tend to\nhave smaller perturbative corrections than the corresponding unsmeared\noperators. We use these operators to calculate kaon weak matrix elements on\nquenched ensembles at $\\beta=6.0$, 6.2 and 6.4. Extrapolating to the continuum\nlimit, we find $B_K(NDR, 2 GeV)= 0.62\\pm 0.02(stat)\\pm 0.02(syst)$. The\nsystematic error is dominated by the uncertainty in the matching between\nlattice and continuum operators due to the truncation of perturbation theory at\none-loop. We do not include any estimate of the errors due to quenching or to\nthe use of degenerate $s$ and $d$ quarks. For the $\\Delta I = {3/2}$\nelectromagnetic penguin operators we find $B_7^{(3/2)} = 0.62\\pm 0.03\\pm 0.06$\nand $B_8^{(3/2)} = 0.77\\pm 0.04\\pm 0.04$. We also use the ratio of unsmeared to\nsmeared operators to make a partially non-perturbative estimate of the\nrenormalization of the quark mass for staggered fermions. We find that tadpole\nimproved perturbation theory works well if the coupling is chosen to be\n$\\alpha_\\MSbar(q^*=1/a)$.",
        "positive": "Hadronic structure from the lattice: In recent years the investigation of hadron structure using lattice\ntechniques has attracted growing attention. In this talk we give an overview on\nrecent work with a focus on results for nucleon spectrum and structure from the\nQCDSF collaboration."
    },
    {
        "anchor": "Charmed Meson Spectroscopy and Matrix Elements with an O(a)-Improved\n  Clover Fermion Action: We present preliminary results for the spectrum and decay matrix elements for\nheavy-light and heavy-heavy mesons, obtained on the 64-node Meiko Computing\nSurface at the University of Edinburgh. Quark propagators are computed with an\nO(a)-improved fermion action on 24^3x48 lattices at beta = 6.2, using three\nvalues of the quark mass up to around the strange quark mass, and four values\nof the quark mass in the region of the charm quark mass. We compare results for\nthe hyperfine splitting in charmonium with those obtained using the\nconventional Wilson fermion action and find that the splitting is 1.83(15)\ntimes larger with the improved action. Our measurements of f_B indicate\nnon-scaling corrections of the order of 20% to the Heavy Quark Effective Theory\nexpectation. A comparison is made with results obtained on 16^3x48 lattices at\nbeta = 6.0.",
        "positive": "Linear lattice gauge theory: Linear lattice gauge theory is based on link variables that are arbitrary\ncomplex or real $N\\times N$ matrices, in distinction to the usual (non-linear)\nformulation with unitary or orthogonal matrices. For a large region in\nparameter space both formulations belong to the same universality class, such\nthat the continuum limits of linear and non-linear lattice gauge theory are\nidentical. We explore if the linear formulation can help to find a\nnon-perturbative continuum limit formulated in terms of continuum fields.\nLinear lattice gauge theory exhibits excitations beyond the gauge fields. In\nthe linear formulation the running gauge coupling corresponds to the flow of\nthe minimum of a ``link potential''. This minimum occurs for a nonzero value of\nthe link variable $l_0$ in the perturbative regime, while $l_0$ vanishes in the\nconfinement regime. We discuss a flow equation for the scale dependent location\nof the minimum $l_0(k)$."
    },
    {
        "anchor": "A note on the practical feasibility of domain-wall fermions: Domain-wall fermions preserve chiral symmetry up to terms that decrease\nexponentially when the lattice size in the fifth dimension is taken to\ninfinity. The associated rates of convergence are given by the low-lying\neigenvalues of a simple local operator in four dimensions. These can be\ncomputed using the Ritz functional technique and it turns out that the\nconvergence tends to be extremely slow in the range of lattice spacings\nrelevant to large-volume numerical simulations of lattice QCD. Two methods to\nimprove on this situation are discussed.",
        "positive": "The QCD phase transition at high temperature and low density: We study the thermal properties of QCD in the presence of a small quark\nchemical potential $\\mu$. Derivatives of the phase transition point with\nrespect to $\\mu$ are computed at $\\mu=0$ for 2 and 3 flavors of p-4 improved\nstaggered fermions on a $16^3\\times4$ lattice. Moreover we contrast the case of\nisoscalar and isovector chemical potentials, quantify the effect of $\\mu\\not=0$\non the equation of state, and comment on the screening effect by dynamical\nquarks and the complex phase of the fermion determinant in QCD with\n$\\mu\\not=0$."
    },
    {
        "anchor": "Towards extracting the timelike pion form factor on CLS two-flavour\n  ensembles: Results are presented from an ongoing study of the $\\rho$ resonance. The\nfocus is on CLS 2-flavour ensembles generated using $\\mathcal{O}(a)$ improved\nWilson fermions with pion masses ranging from $265$ to $437$ $\\mathrm{MeV}$.\nThe energy levels are extracted by solving the GEVP of correlator matrices,\ncreated with the distillation approach involving $\\rho$ and $\\pi\\pi$\ninterpolators. The study is done in the centre-of-mass frame and several moving\nframes. One aim of this work is to extract the timelike pion form factor after\napplying the L\\\"uscher formalism. We therefore plan to integrate this study\nwith the existing Mainz programme for the calculation of the hadronic vacuum\npolarization contribution to the muon $g-2$.",
        "positive": "Orientifold Planar Equivalence: The Chiral Condensate: The recently introduced orientifold planar equivalence is a promising tool\nfor solving non-perturbative problems in QCD. One of the predictions of\norientifold planar equivalence is that the chiral condensates of a theory with\n$N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric)\nrepresentation and $N_f$ flavours of Majorana fermions in the adjoint\nrepresentation have the same large $N$ value for any value of the mass of the\n(degenerate) fermions. Assuming the invariance of the theory under charge\nconjugation, we prove this statement on the lattice for staggered quenched\ncondensates in SU($N$) Yang-Mills in the large $N$ limit. Then, we compute\nnumerically those quenched condensates for $N$ up to 8. After separating the\neven from the odd corrections in $1/N$, we are able to show that our data\nsupport the equivalence; however, unlike other quenched observables, subleading\nterms in $1/N$ are needed for describing the data for the symmetric and\nantisymmetric representation at $N$=3. Possible lessons for the unquenched case\nare discussed."
    },
    {
        "anchor": "Chiral spin symmetry and hot/dense QCD: Above the chiral symmetry restoration crossover around T_{ch} ~ 155 MeV a new\nregime arises in QCD, a stringy fluid, which is characterized by an approximate\nchiral spin symmetry of the thermal partition function. This symmetry is not a\nsymmetry of the Dirac Lagrangian and is a symmetry of the electric part of the\nQCD Lagrangian. In this regime the medium consists of the chirally symmetric\nand approximately chiral spin symmetric hadrons that are made of the chirally\nsymmetric quarks connected into the color singlet compounds by a confining\nchromoelectric field. This regime is evidenced by the approximate chiral spin\nsymmetry of the spatial and temporal correlators and by the breakdown of the\nthermal perturbation theory at the crossover between the partonic (the\nquark-gluon plasma) and stringy fluid regimes at ~ 3 T_{ch}. The chiral spin\nsymmetry smoothly disappears above ~ 3T_{ch} which means that the\nchromoelectric confining interaction gets screened. A direct evidence that the\nstringy fluid medium consists of densely packed hadrons is the pion spectral\nfunction that shows a distinct pion state and its first radial excitation above\nT_{ch}. Another direct evidence of the hadron degrees of freedom in the stringy\nfluid is the bottomonium spectrum with the 1S,2S,3S and 1P,2P radial and\norbital excitations that become broad with temperature. The hadrons between\nT_{ch} and ~ 3 T_{ch} in the stringy fluid interact strongly which makes the\nstringy fluid more a liquid rather than a gas. We discuss how this chiral spin\nsymmetric regime extends into the finite chemical potentials domain and present\na qualitative sketch of the QCD phase diagram.",
        "positive": "Charge Symmetry Breaking in Parton Distribution Functions from Lattice\n  QCD: By determining the quark momentum fractions of the octet baryons from N_f=2+1\nlattice simulations, we are able to predict the degree of charge symmetry\nviolation in the parton distribution functions of the nucleon. This is of\nimportance, not only as a probe of our understanding of the non-perturbative\nstructure of the proton but also because such a violation constrains the\naccuracy of global fits to parton distribution functions and hence the accuracy\nwith which, for example, cross sections at the LHC can be predicted. A\nviolation of charge symmetry may also be critical in cases where symmetries are\nused to guide the search for physics beyond the Standard Model."
    },
    {
        "anchor": "Lattice renormalisation of O(a) improved heavy-light operators: The analytical expressions and the numerical values of the renormalisation\nconstants of ${\\cal O}(a)$ improved static-light currents are given at one-loop\norder of perturbation theory in the framework of Heavy Quark Effective Theory:\nthe static quark is described by the HYP action and the light quark is\ndescribed either with the Clover or the Neuberger action. These factors are\nrelevant to extract from a lattice computation the decay constants $f_B$,\n$f_{B_S}$ and the set of bag parameters $B_i$ associated with $B-\\bar{B}$\nmixing phenomenology in the Standard Model and beyond.",
        "positive": "Taming the pion condensation in QCD at finite baryon density: In the Monte Carlo study of QCD at finite baryon density based upon the phase\nreweighting method, the pion condensation in the phase-quenched theory and\nassociated zero-mode prevent us to go to the low-temperature high-density\nregion. We propose a method to circumvent them by a simple modification of the\ndensity of state method. We first argue that the standard version of the\ndensity of state method, which is invented to solve the overlapping problem, is\neffective only for a certain `good' class of observables. We then modify it so\nas to solve the overlap problem for `bad' observables as well. While, in the\nstandard version of the density of state method, we usually constrain an\nobservable we are interested in, we fix a different observable in our new\nmethod which has a sharp peak at some particular value characterizing the\ncorrect vacuum of the target theory. In the finite-density QCD, such an\nobservable is the pion condensate. The average phase becomes vanishingly small\nas the value of the pion condensate becomes large, hence it is enough to\nconsider configurations with small values of pion condensate, where the zero\nmode does not appear. We demonstrate an effectiveness of our method by using a\ntoy model (the chiral random matrix theory) which captures the properties of\nfinite-density QCD qualitatively. We also argue how to apply our method to\nother theories including finite-density QCD. Although the example we study\nnumerically is based on the phase reweighting method, the same idea can be\napplied to more general reweighting methods and we show how this idea can be\napplied to find a possible QCD critical point."
    },
    {
        "anchor": "$SO(4)$ invariant Higgs-Yukawa model with reduced staggered fermions: We explore the phase structure of a four dimensional $SO(4)$ invariant\nlattice Higgs-Yukawa model comprising four reduced staggered fermions\ninteracting with a real scalar field. The fermions belong to the fundamental\nrepresentation of the symmetry group while the three scalar field components\ntransform in the self-dual representation of $SO(4)$. The model is a\ngeneralization of a four fermion system with the same symmetries that has\nreceived recent attention because of its unusual phase structure comprising\nmassless and massive symmetric phases separated by a very narrow phase in which\na small bilinear condensate breaking $SO(4)$ symmetry is present. The\ngeneralization described in this paper simply consists of the addition of a\nscalar kinetic term. We find a region of the enlarged phase diagram which shows\nno sign of a fermion condensate or symmetry breaking but in which there is\nnevertheless evidence of a diverging correlation length. Our results in this\nregion are consistent with the presence of a single continuous phase transition\nseparating the massless and massive symmetric phases observed in the earlier\nwork.",
        "positive": "A library of extended high-temperature expansions of basic observables\n  for the spin S Ising models on two- and three-dimensional lattices: We present an on-line library of unprecedented extension for high-temperature\nexpansions of basic observables in the Ising models of general spin S, with\nnearest-neighbor interactions.\n  We have tabulated through order beta^{25} the series for the nearest-neighbor\ncorrelation function, the susceptibility and the second correlation moment in\ntwo dimensions on the square lattice, and, in three dimensions, on the\nsimple-cubic and the body-centered cubic lattices. The expansion of the second\nfield derivative of the susceptibility is also tabulated through beta^{23} for\nthe same lattices. We have thus added several terms (from four up to thirteen)\nto the series already published for spin\n  S=1/2,1,3/2,2,5/2,3,7/2,4,5,infinity."
    },
    {
        "anchor": "A Lattice Study of Quark and Glue Momenta and Angular Momenta in the\n  Nucleon: We report a complete calculation of the quark and glue momenta and angular\nmomenta in the proton. These include the quark contributions from both the\nconnected and disconnected insertions. The quark disconnected insertion loops\nare computed with $Z_4$ noise, and the signal-to-noise is improved with\nunbiased subtractions. The glue operator is comprised of gauge-field tensors\nconstructed from the overlap operator. The calculation is carried out on a\n$16^3 \\times 24$ quenched lattice at $\\beta = 6.0$ for Wilson fermions with\n$\\kappa=0.154, 0.155$, and $0.1555$ which correspond to pion masses at $650,\n538$, and $478$~MeV, respectively. The chirally extrapolated $u$ and $d$ quark\nmomentum/angular momentum fraction is found to be $0.64(5)/0.70(5)$, the\nstrange momentum/angular momentum fraction is $0.024(6)/0.023(7)$, and that of\nthe glue is $0.33(6)/0.28(8)$. The previous study of quark spin on the same\nlattice revealed that it carries a fraction of $0.25(12)$ of proton spin. The\norbital angular momenta of the quarks are then obtained from subtracting the\nspin from their corresponding angular momentum components. We find that the\nquark orbital angular momentum constitutes $0.47(13)$ of the proton spin with\nalmost all of it coming from the disconnected insertions.",
        "positive": "Excited and exotic charmonium, $D_s$ and $D$ meson spectra for two light\n  quark masses from lattice QCD: We present highly-excited charmonium, $D_s$ and $D$ meson spectra from\ndynamical lattice QCD calculations with light quarks corresponding to $M_{\\pi}\n\\sim 240$ MeV and compare these to previous results with $M_{\\pi} \\sim 400$\nMeV. Utilising the distillation framework, large bases of carefully constructed\ninterpolating operators and a variational procedure, we extract and reliably\nidentify the continuum spin of an extensive set of excited mesons. These\ninclude states with exotic quantum numbers which, along with a number with\nnon-exotic quantum numbers, we identify as having excited gluonic degrees of\nfreedom and interpret as hybrid mesons. Comparing the spectra at the two\ndifferent $M_\\pi$, we find only a mild light-quark mass dependence and no\nchange in the overall pattern of states."
    },
    {
        "anchor": "The $\u03c1$-resonance with physical pion mass from $N_f=2$ lattice QCD: We present the first-ever lattice computation of pi pi-scattering in the I=1\nchannel with Nf=2 dynamical quark flavours obtained including an ensemble with\nphysical value of the pion mass. Employing a global fit to data at three values\nof the pion mass, we determine the universal parameters of the rho-resonance.\nWe carefully investigate systematic uncertainties by determining energy\neigenvalues using different methods and by comparing inverse amplitude method\nand Breit-Wigner type parametrizations. Overall, we find mass 786(20) MeV and\nwidth 180(6) MeV, including statistical and systematic uncertainties. In stark\ndisagreement with the previous Nf=2 extrapolations from higher than physical\npion mass results, our mass value is in good agreement with experiment, while\nthe width is slightly too high.",
        "positive": "Exploring Partially Confined Phases: Phases of SU(N) gauge theories in which the global Z(N) symmetry breaks\nspontaneously to a subgroup Z(L) can be realized by adding appropriate Wilson\nline terms to the gauge action. These phases are partially confining, in the\nsense that quarks are confined but bound states of L quarks are not. At\ntemperatures large compared to the normal deconfinement temperature, the phase\ndiagram, pressure, string tensions, and 't Hooft loop surface tensions can be\ncalculated analytically. Approximate scaling laws emerge naturally for both\nstring tensions and surface tensions."
    },
    {
        "anchor": "The Chirality of $b$ Quark Couplings: This review addresses the question of the chirality of $b$ quark weak\ncouplings from a theoretical and from a purely phenomenological point of view.\nDue to their small magnitude $b$ decay couplings are subject to possible large\ncorrections from right-handed terms, on the one hand, and do not affect the\nweak interactions of the first two quark families in any observable manner, on\nthe other hand. This motivated an $SU(2)_L\\times SU(2)_R\\times U(1)$ model with\npurely right-handed $b$-decay couplings. The model is consistent with\nexperiments, including recent measurements of a lepton forward-backward\nasymmetry in $B\\to D^*\\ell\\nu$ and of radiative $B$ decays. Parity violating\nasymmetries in semileptonic decays of polarized $\\Lambda_b$ baryons produced in\n$Z^0$ decays provide a promising way of measuring the chirality of the $b$ to\n$c$ current.",
        "positive": "Large-Nc equivalence and the sign problem at finite baryon density: QCD with a finite baryon chemical potential, despite its importance, is not\nwell understood because the standard lattice QCD simulation is not applicable\ndue to the sign problem. Although QCD-like theories which do not suffer from\nthe sign problem have been studied intensively, relation to QCD with a finite\nbaryon chemical potential was not clear. This paper introduces large-$N_c$\nequivalences between QCD and various QCD-like theories. These equivalences lead\nus to a unified viewpoint for QCD with baryon and isospin chemical potentials,\n$SO(2N_c)$ and $Sp(2N_c)$ gauge theories, QCD with adjoint matters and\ntwo-color QCD. In particular QCD with the baryon chemical potential is\nlarge-$N_c$ equivalent to its phase quenched version in a certain parameter\nregion, which is relevant for heavy ion collision experiments. All previous\nsimulation results which study the effect of the phase confirm the phase quench\napproximation is quantitatively good already at Nc=3; it is so good that often\ntwo theories give the same value within error. Therefore the phase quenched\nsimulation is the best strategy for the QCD critical point search. At small\nvolume one can study a tiny 1/Nc effect by the phase reweighting; the large-Nc\nequivalence guarantees that the phase reweighing method works without suffering\nfrom the overlapping problem."
    },
    {
        "anchor": "Numerical simulation of N=1 supersymmetric Yang-Mills theory: We present results from a lattice study of SU(2) color, N=1 supersymmetric\nYang-Mills theory using domain wall fermions. Supersymmetry in this particular\nlattice formulation is expected to emerge in the continuum and chiral limits\nwithout any fine-tuning of operators. Preliminary results for the static quark\npotential, residual mass, chiral condensate and spectrum--a potential indicator\nof supersymmetry restoration--are presented and discussed.",
        "positive": "Dynamical overlap fermions, results with hybrid Monte-Carlo algorithm: We present first, exploratory results of a hybrid Monte-Carlo algorithm for\ndynamical, n_f=2, four-dimensional QCD with overlap fermions. As expected, the\ncomputational requirements are typically two orders of magnitude larger for the\ndynamical overlap formalism than for the more conventional (Wilson or\nstaggered) formulations."
    },
    {
        "anchor": "Update on the physics of light pseudoscalar mesons: We present an update of the MILC investigation of the properties of light\npseudoscalar mesons using three flavors of improved staggered quarks. Results\nare presented for the $\\pi$ and $K$ leptonic decay constants, the CKM matrix\nelement $V_{us}$, the up, down and strange quark masses, and the coefficients\nof the $O(p^4)$ chiral lagrangian. We have new data for lattice spacing $a\n\\approx 0.15$ fm with several values of the light quark mass down to one-tenth\nthe strange quark mass, higher statistics for $a \\approx 0.09$ fm with the\nlight quark mass equal to one-tenth the strange quark mass, and initial results\nfor our smallest lattice spacing, $a \\approx 0.06$ fm with light quark mass\ntwo-fifths of the strange quark mass.",
        "positive": "Perturbative Wilson loops from unquenched Monte Carlo simulations at\n  weak couplings: Perturbative expansions of several small Wilson loops are computed through\nnext-to-next-to-leading order in unquenched lattice QCD, from Monte Carlo\nsimulations at weak couplings. This approach provides a much simpler\nalternative to conventional diagrammatic perturbation theory, and is applied\nhere for the first time to full QCD. Two different sets of lattice actions are\nconsidered: one set uses the unimproved plaquette gluon action together with\nthe unimproved staggered-quark action; the other set uses the one-loop-improved\nSymanzik gauge-field action together with the so-called ``asqtad''\nimproved-staggered quark action. Simulations are also done with different\nnumbers of dynamical fermions. An extensive study of the systematic\nuncertainties is presented, which demonstrates that the small third-order\nperturbative component of the observables can be reliably extracted from\nsimulation data. We also investigate the use of the rational hybrid Monte Carlo\nalgorithm for unquenched simulations with unimproved-staggered fermions. Our\nresults are in excellent agreement with diagrammatic perturbation theory, and\nprovide an important cross-check of the perturbation theory input to a recent\ndetermination of the strong coupling $\\alpha_{\\bar{\\rm MS}}(M_Z)$ by the HPQCD\ncollaboration."
    },
    {
        "anchor": "Correlation functions and critical behaviour on fluctuating geometries: We study the two-point correlation function in the model of branched polymers\nand its relation to the critical behaviour of the model. We show that the\ncorrelation function has a universal scaling form in the generic phase with the\nonly scale given by the size of the polymer. We show that the origin of the\nsingularity of the free energy at the critical point is different from that in\nthe standard statistical models. The transition is related to the change of the\ndimensionality of the system.",
        "positive": "On the lattice construction of electroweak gauge theory: Based on the Ginsparg-Wilson relation, a gauge invariant formulation of\nelectroweak SU(2)xU(1) gauge theory on the lattice is considered. If the\nhypercharge gauge coupling is turned off in the vacuum sector of the U(1) gauge\nfields, the theory consists of four left-handed SU(2) doublets and it is\npossible, as in vector-like theories, to make the fermion measure defined\nglobally in all topological sectors of SU(2). We then try to incorporate U(1)\ngauge field, following L\\\"uscher's reconstruction theorem. The global\nintegrability condition is proved for ``gauge loops'' in the space of the U(1)\ngauge fields with arbitrary SU(2) gauge field fixed in the background. For\n``non-gauge loops'', however, the proof is given so far only for the classical\nSU(2) instanton backgrounds."
    },
    {
        "anchor": "Meson-Baryon Scattering Lengths from Mixed-Action Lattice QCD: The $\\pi^+\\Sigma^+$, $\\pi^+\\Xi^0$, $K^+p$, $K^+n$, and $\\overline{K}{}^0\n\\Xi^0$ scattering lengths are calculated in mixed-action Lattice QCD with\ndomain-wall valence quarks on the asqtad-improved coarse MILC configurations at\nfour light-quark masses, and at two light-quark masses on the fine MILC\nconfigurations. Heavy Baryon Chiral Perturbation Theory with two and three\nflavors of light quarks is used to perform the chiral extrapolations. To the\norder we work in the three-flavor chiral expansion, the kaon-baryon processes\nthat we investigate show no signs of convergence. Using the two-flavor chiral\nexpansion for extrapolation, the pion-hyperon scattering lengths are found to\nbe $a_{\\pi^+\\Sigma^+}=-0.197\\pm0.017$ fm, and $a_{\\pi^+\\Xi^0}=-0.098\\pm0.017$\nfm, where the comprehensive error includes statistical and systematic\nuncertainties.",
        "positive": "Study of lattice QCD at finite baryon density using the canonical\n  approach: At finite baryon density lattice QCD first-principle calculations can not be\nperformed due to the sign problem. In order to circumvent this problem, we use\nthe canonical approach, which provides reliable analytical continuation from\nthe imaginary chemical potential region to the real chemical potential region.\nWe briefly present the canonical partition function method, describe our\nformulation, and show the results, obtained for two temperatures: $T/T_c =\n0.93$ and $T/T_c = 0.99$ in lattice QCD with two flavors of improved Wilson\nfermions."
    },
    {
        "anchor": "Isospin Breaking Effects on the Lattice: Isospin symmetry is not exact and the corrections to the isosymmetric limit\nare, in general, at the percent level. For gold plated quantities, such as\npseudoscalar meson masses or the kaon leptonic and semileptonic decay rates,\nthese effects are of the same order of magnitude of the errors quoted in\nnowadays lattice calculations and cannot be neglected any longer. In this talk\nI discuss the methods that have been developed in the last few years to\ncalculate isospin breaking corrections by starting from first principles\nlattice simulations. In particular, I discuss how to perform a combined QCD+QED\nlattice simulation and a renormalization prescription to be used in order to\nseparate QCD from QED isospin breaking effects. A brief review of recent\nlattice results of isospin breaking effects on the hadron spectrum is also\nincluded.",
        "positive": "Four-dimensional pure compact U(1) gauge theory on a spherical lattice: We investigate the confinement-Coulomb phase transition in the\nfour-dimensional (4D) pure compact U(1) gauge theory on spherical lattices. The\naction contains the Wilson coupling beta and the double charge coupling gamma.\nThe lattice is obtained from the 4D surface of the 5D cubic lattice by its\nradial projection onto a 4D sphere, and made homogeneous by means of\nappropriate weight factors for individual plaquette contributions to the\naction. On such lattices the two-state signal, impeding the studies of this\ntheory on toroidal lattices, is absent for gamma le 0. Furthermore, here a\nconsistent finite-size scaling behavior of several bulk observables is found,\nwith the correlation length exponent nu in the range nu = 0.35 - 40. These\nobservables include Fisher zeros, specific-heat and cumulant extrema as well as\npseudocritical values of beta at fixed gamma. The most reliable determination\nof nu by means of the Fisher zeros gives nu = 0.365(8). The phase transition at\ngamma le 0 is thus very probably of 2nd order and belongs to the universality\nclass of a non-Gaussian fixed point."
    },
    {
        "anchor": "Decay Constants of B and D Mesons from Non-perturbatively Improved\n  Lattice QCD: The decay constants of B, D and K mesons are computed in quenched lattice QCD\nat two different values of the coupling. The action and operators are O(a)\nimproved with non-perturbative coefficients. The results are\nf_B=195(6)(+24/-23) MeV, f_D=206(4)(+17/-10) MeV, f_B_s=220(6)(+23/-28) MeV,\nf_D_s=229(3)(+23/-12) MeV and f_K= 150(3)(+12/-8) MeV. Systematic errors are\ndiscussed in detail. Results for vector decay constants, flavour symmetry\nbreaking ratios of decay constants, the pseudoscalar-vector mass splitting and\nD meson masses are also presented.",
        "positive": "Electromagnetic and spin polarisabilities in lattice QCD: We discuss the extraction of the electromagnetic and spin polarisabilities of\nnucleons from lattice QCD. We show that the external field method can be used\nto measure all the electromagnetic and spin polarisabilities including those of\ncharged particles. We then turn to the extrapolations required to connect such\ncalculations to experiment in the context of chiral perturbation theory,\nfinding a strong dependence on the lattice volume and quark masses."
    },
    {
        "anchor": "Massless Schwinger model with a 4-fermi interaction at topological angle\n  $\u03b8= \u03c0$: We study the massless Schwinger model with an additional 4-fermi interaction\nand a topological term. For topological angle $\\theta = \\pi$ charge conjugation\nsymmetry is implemented in a non-trivial way and we study the possibility of\nits spontaneous breaking. For the lattice discretization we use staggered\nfermions and the Villain action for the gauge fields, where the topological\nterm is an integer and charge conjugation at $\\theta = \\pi$ is an exact\nsymmetry. The complex action problem is overcome by a suitable\nworldline/worldsheet representation. We find that as a function of the 4-fermi\ncoupling the system shows a critical point separating a weak coupling phase\nwhere charge conjugation symmetry is intact from a strong coupling phase with\nspontaneously broken charge conjugation symmetry.",
        "positive": "Bottomonium hyperfine splittings from lattice NRQCD including radiative\n  and relativistic corrections: We present a calculation of the hyperfine splittings in bottomonium using\nlattice Nonrelativistic QCD. The calculation includes spin-dependent\nrelativistic corrections through O(v^6), radiative corrections to the leading\nspin-magnetic coupling and, for the first time, non-perturbative 4-quark\ninteractions which enter at alpha_s^2 v^3. We also include the effect of u,d,s\nand c quark vacuum polarisation. Our result for the 1S hyperfine splitting is\nM(Upsilon,1S) - M(eta_b,1S)= 60.0(6.4) MeV. We find the ratio of 2S to 1S\nhyperfine splittings (M(Upsilon,2S) - M(eta_b,2S))/ (M(Upsilon,1S) -\nM(eta_b,1S)) = 0.445(28)."
    },
    {
        "anchor": "Critical line of 2+1 flavor QCD: Toward the continuum limit: We determine the continuum limit of the curvature of the pseudocritical line\nof QCD with $n_f$=2+1 staggered fermions at nonzero temperature and quark\ndensity. We perform Monte Carlo simulations at imaginary baryon chemical\npotentials, adopting the HISQ/tree action discretization, as implemented in the\ncode by the MILC collaboration. Couplings are adjusted so as to move on a line\nof constant physics, as determined in Ref.~\\cite{Bazavov:2011nk}, with the\nstrange quark mass $m_s$ fixed at its physical value and a light-to-strange\nmass ratio $m_l/m_s=1/20$. The chemical potential is set at the same value for\nthe three quark species, $\\mu_l=\\mu_s\\equiv \\mu$. We attempt an extrapolation\nto the continuum using the results on lattices with temporal size up to\n$L_t=12$. Our estimate for the continuum value of the curvature $\\kappa$ at\nzero baryon density, $\\kappa=0.020(4)$, is compared with recent lattice results\nand with experimental determinations of the freeze-out curve.",
        "positive": "Radiative corrections to the lattice gluon action for highly improved\n  staggered quarks (HISQ) and the effect of such corrections on the static\n  potential: We perform a perturbative calculation of the influence of dynamical HISQ\nfermions on the perturbative improvement of the gluonic action in the same way\nas we have previously done for asqtad fermions. We find the fermionic\ncontributions to the radiative corrections in the Luescher-Weisz gauge action\nto be somewhat larger for HISQ fermions than for asqtad. Using one-loop\nperturbation theory as a test, we estimate that omission of the fermion-induced\nradiative corrections in dynamical asqtad simulations will give a measurable\neffect. The one-loop result gives a systematic shift of about -0.6% in (r_1/a)\non the coarsest asqtad improved staggered ensembles. This is the correct sign\nand magnitude to explain the scaling violations seen in Phi_B on dynamical\nlattice ensembles."
    },
    {
        "anchor": "Matrix product representation of gauge invariant states in a Z_2 lattice\n  gauge theory: The Gauss law needs to be imposed on quantum states to guarantee gauge\ninvariance when one studies gauge theory in hamiltonian formalism. In this\nwork, we propose an efficient variational method based on the matrix product\nansatz for a Z_2 lattice gauge theory on a spatial ladder chain. Gauge\ninvariant low-lying states are identified by evaluating expectation values of\nthe Gauss law operator after numerical diagonalization of the gauge\nhamiltonian.",
        "positive": "The scaling region of the lattice O(N) sigma model at finite temperature: We present results from numerical studies of the finite temperature phase\ntransition of the $(3+1)d$ O(N)-symmetric non-linear sigma model for $N=1,2$\nand 3. We study the dependence of the width of the 3d critical region on $N$\nand we show that the broken phase scaling region is much wider for N=2 and 3\nthan for N=1. We also compare the widths of the critical region in the low $T$\nand high $T$ phases of the O(2) model and we show that the scaling region in\nthe broken phase is much wider than in the symmetric phase. We also report\nresults for the width of the scaling regions in the low $T$ phase$ (2+1)d$\nIsing model and we show that the spatial correlation length has to be\napproximately twice the lattice temporal extent before the 2d scaling region is\nreached."
    },
    {
        "anchor": "Compact Lattice QED with Staggered Fermions and Chiral Symmetry Breaking: Different formulations of the $4d$ compact lattice QED with staggered\nfermions (standard Wilson and modified by suppression of lattice artifacts) are\ninvestigated by Monte Carlo simulations within the quenched approximation. We\nshow that after suppressing lattice artifacts the system undergoes a phase\ntransition from the Coulomb phase into a presumably weakly chirally broken\nphase only at (unphysical) negative $\\beta$--values.",
        "positive": "Photon Structure Functions from Quenched Lattice QCD: We calculate the first moment of the photon structure function,\n$<x>^{\\gamma}=\\int^1_0 dx F^{\\gamma}_2(x,Q^2)$, on the quenched lattices with\n$\\beta=6.0$ using the formalism developed by the authors recently. In this\nexploratory study, we take into account only the connected contractions. The\nresult is compared with the experimental data as well as model predictions."
    },
    {
        "anchor": "Deconfinement, gradient and cooling scales for pure SU(2) lattice gauge\n  theory: We investigate the approach of pure SU(2) lattice gauge theory with the\nWilson action to its continuum limit using the deconfining phase transition,\nthe gradient flow and the cooling flow to set the scale. For the gradient and\ncooling scales we explore three different energy observables and two distinct\nreference values for the flow time. When the aim is to follow scaling towards\nthe continuum limit, one gains at least a factor of 100 in computational\nefficiency by relying on the gradient instead of the deconfinement scale. Using\ncooling instead of the gradient flow one gains another factor of at least 34 in\ncomputational efficiency on the gradient flow part without any significant loss\nin the accuracy of scale setting. Concerning our observables, the message is to\nkeep it simple. The Wilson action itself performs as well as or even better\nthan the other two observables explored. Two distinct fitting forms for scaling\nare compared of which one connects to asymptotic scaling. Differences of the\nobtained estimates show that systematic errors of length ratios, though only\nabout 1%, can be considerably larger than statistical errors of the same\nobservables.",
        "positive": "Three-point functions in noncompact lattice QED: We calculate fermion-antifermion-\"meson\" three-point functions in noncompact\nlattice QED with dynamical staggered fermions and use them to extract effective\nYukawa couplings. The results are consistent with the hypothesis that QED is\ntrivial."
    },
    {
        "anchor": "Machine Learning and Variational Algorithms for Lattice Field Theory: In lattice quantum field theory studies, parameters defining the lattice\ntheory must be tuned toward criticality to access continuum physics. Commonly\nused Markov chain Monte Carlo (MCMC) methods suffer from critical slowing down\nin this limit, restricting the precision of continuum extrapolations. Further\ndifficulties arise when measuring correlation functions of operators widely\nseparated in spacetime: for most correlation functions, an exponentially severe\nsignal-to-noise problem is encountered as the operators are taken to be widely\nseparated. This dissertation details two new techniques to address these\nissues. First, we define a novel MCMC algorithm based on generative flow-based\nmodels. Such models utilize machine learning methods to describe efficient\napproximate samplers for distributions of interest. Independently drawn\nflow-based samples are then used as proposals in an asymptotically exact\nMetropolis-Hastings Markov chain. We address incorporating symmetries of\ninterest, including translational and gauge symmetries. We secondly introduce\nan approach to \"deform\" Monte Carlo estimators based on contour deformations\napplied to the domain of the path integral. The deformed estimators associated\nwith an observable give equivalent unbiased measurements of that observable,\nbut generically have different variances. We define families of deformed\nmanifolds for lattice gauge theories and introduce methods to efficiently\noptimize the choice of manifold (the \"observifold\"), minimizing the deformed\nobservable variance. Finally, we demonstrate that flow-based MCMC can mitigate\ncritical slowing down and observifolds can exponentially reduce variance in\nproof-of-principle applications to scalar $\\phi^4$ theory and $\\mathrm{U}(1)$\nand $\\mathrm{SU}(N)$ lattice gauge theories.",
        "positive": "Observation of FSS for a First Order Phase Transition: We present the results of a multicanonical simulation of the q=20 2-d Potts\nmodel in the transition region. This is a very strong first order phase\ntransition. We observe, for the first time, the asymptotic finite size scaling\nbehavior predicted by Borgs and Koteck\\'y close to a first order phase\ntransition point."
    },
    {
        "anchor": "Finite density (might well be easier) at finite temperature: Experiments with imaginary chemical potential and Glasgow method carried out\nin two interrelated models - four dimensional QCD in the infinite coupling\nlimit, and one dimensional QCD - support the point of view expressed by the\ntitle.",
        "positive": "Genetic Algorithm for SU(2) Gauge Theory on a 2-dimensional Lattice: An algorithm is proposed for the simulation of pure SU(N) lattice gauge\ntheories based on Genetic Algorithms(GAs). We apply GAs to SU(2) pure gauge\ntheory on a 2 dimensional lattice and show the results, the action per\nplaquette and Wilson loops, are consistent with those by Metropolis method(MP)s\nand Heatbath method(HB)s. Thermalization speed of GAs is especially faster than\nthe simple MPs."
    },
    {
        "anchor": "A method for putting chiral fermions on the lattice: We describe a method to put chiral gauge theories on the lattice. Our method\nmakes heavy use of the effective action for chiral fermions in the continuum,\nwhich is in general complex. As an example we discuss the chiral Schwinger\nmodel.",
        "positive": "Four-loop lattice-regularized vacuum energy density of the\n  three-dimensional SU(3) + adjoint Higgs theory: The pressure of QCD admits at high temperatures a factorization into purely\nperturbative contributions from \"hard\" thermal momenta, and slowly convergent\nas well as non-perturbative contributions from \"soft\" thermal momenta. The\nlatter can be related to various effective gluon condensates in a dimensionally\nreduced effective field theory, and measured there through lattice simulations.\nPractical measurements of one of the relevant condensates have suffered,\nhowever, from difficulties in extrapolating convincingly to the continuum\nlimit. In order to gain insight on this problem, we employ Numerical Stochastic\nPerturbation Theory to estimate the problematic condensate up to 4-loop order\nin lattice perturbation theory. Our results seem to confirm the presence of\n\"large\" discretization effects, going like $a\\ln(1/a)$, where $a$ is the\nlattice spacing. For definite conclusions, however, it would be helpful to\nrepeat the corresponding part of our study with standard lattice perturbation\ntheory techniques."
    },
    {
        "anchor": "Preparing for N_f=2 simulations at small lattice spacings: We discuss some large effects of dynamical fermions. One is a cutoff effect,\nothers concern the contribution of multi-pion states to correlation functions\nand are expected to survive the continuum limit. We then turn to the\npreparation for simulations at small lattice spacings which we are planning\ndown to around a=0.04fm in order to understand the size of O(a^2)-effects of\nthe standard O(a)-improved theory. The dependence of the lattice spacing on the\nbare coupling is determined through the Schr\"odinger functional renormalized\ncoupling.",
        "positive": "Lattice gauge theory with baryons at strong coupling: We study the effective Hamiltonian for strong-coupling lattice QCD in the\ncase of non-zero baryon density. In leading order the effective Hamiltonian is\na generalized antiferromagnet. For naive fermions, the symmetry is U(4N_f) and\nthe spins belong to a representation that depends on the local baryon number.\nNext-nearest-neighbor (nnn) terms in the Hamiltonian break the symmetry to\nU(N_f) x U(N_f). We transform the quantum problem to a Euclidean sigma model\nwhich we analyze in a 1/N_c expansion. In the vacuum sector we recover\nspontaneous breaking of chiral symmetry for the nearest-neighbor and nnn\ntheories. For non-zero baryon density we study the nearest-neighbor theory\nonly, and show that the pattern of spontaneous symmetry breaking depends on the\nbaryon density."
    },
    {
        "anchor": "Efficiency of different matrix inversion methods applied to Wilson\n  fermions: We compare different conjugate gradient -- like matrix inversion methods (CG,\nBiCGstab1 and BiCGstab2) employing for this purpose the compact lattice quantum\nelectrodynamics (QED) with Wilson fermions. The main goals of this\ninvestigation are the CPU time efficiency of the methods as well as the\ninfluence of machine precision on the reliability of (physical) results\nespecially close to the 'critical' line $~\\kappa_c(\\bt)$.",
        "positive": "Chiral and deconfinement transitions in strong coupling lattice QCD: We investigate the QCD phase diagram based on the strong coupling expansion\nof the lattice QCD with one species of the staggered fermions at finite\ntemperature (T) and chemical potential (mu). We analytically derive an\neffective potential including both chiral and deconfinement (Z_3) dynamics with\nfinite coupling effects in mean-field approximations. We focus on Polyakov loop\nproperties in whole T-mu plane, and study relations between the chiral and\ndeconfinement crossovers. At a fixed large mu, sequencial rapid variations of\nthe Polyakov loop are observed with increasing T. It is natural to interprete\nthem as the \"chiral induced\" and \"Z_3 induced\" deconfinement crossovers."
    },
    {
        "anchor": "Alleviating the window problem in large volume renormalization schemes: We propose a strategy for large volume non-perturbative renormalization which\nalleviates the window problem by reducing cut-off effects. We perform a\nproof-of-concept study using position space renormalization scheme and the CLS\n$N_f=2+1$ ensembles generated at 5 different lattice spacings. We show that in\nthe advocated strategy results for the renormalization constants are to a large\nextend independent of the specific lattice direction used to define the\nrenormalization condition. Hence, very short lattice distances become\naccessible even on coarse lattices and the contact with perturbation theory can\nbe performed at much higher energy scales. Our results include\nnon-perturbatively estimated renormalization constants for quark bilinear\noperators in the scalar, pseudoscalar and axial-vector channels using position\nspace renormalization scheme which we subsequently translate to the\n$\\overline{\\mathrm{MS}}$ scheme perturbatively at $1.5$ GeV. Our proposal is\napplicable to other non-perturbative large volume renormalization schemes such\nas RI-MOM and its variants.",
        "positive": "The equation of state with nonzero chemical potential for 2+1 flavors: We present results for the QCD equation of state with nonzero chemical\npotential using the Taylor expansion method with terms up to sixth order in the\nexpansion. Our calculations are performed on asqtad 2+1 quark flavor lattices\nat $N_t=4$."
    },
    {
        "anchor": "Critical properties of the 2D Z(5) vector model: The two-dimensional Z(5) vector model is investigated through the\ndetermination of critical points and one critical index. To this purpose a new\ncluster algorithm has been developed valid for 2D Z(N) models with odd values\nof N. Results are compared with analytical predictions.",
        "positive": "Quark confinement to be caused by Abelian or non-Abelian dual\n  superconductivity in the SU(3) Yang-Mills theory: The dual superconductivity is a promising mechanism for quark confinement. We\nhave presented a new formulation of the Yang-Mills theory on the lattice that\nenables us to change the original non-Abelian gauge field into the new field\nvariables such that one of them called the restricted field gives the dominant\ncontribution to quark confinement in the gauge independent way. We have pointed\nout that the SU(3) Yang-Mills theory has another reformulation using new field\nvariables (minimal option), in addition to the way adopted by Cho, Faddeev and\nNiemi (maximal option). In the past lattice conferences, we have shown the\nnumerical evidences that support the non-Abelian dual superconductivity using\nthe minimal option for the SU(3) Yang-Mills theory. This result should be\ncompared with Abelian dual superconductivity obtained in the maximal option\nwhich is a gauge invariant extension of the conventional Abelian projection\nmethod in the maximal Abelian gauge.\n  In this talk, we focus on discriminating between two reformulations, i.e.,\nmaximal and minimal options of the $SU(3)$ Yang-Mills theory from the viewpoint\nof dual superconductivity for quark confinement. We investigate the\nconfinement/deconfinement phase transitions at finite temperature in both\noptions, which are compared with the original Yang-Mills theory. For this\npurpose, we measure the distribution of Polyakov-loops and the Polyakov-loop\naverage, the correlation function of the Polyakov loops and the distribution of\nthe chromoelectric flux connecting a quark and antiquark in both confinement\nand deconfinement phases."
    },
    {
        "anchor": "Reconstructing parton distribution functions from Ioffe time data: from\n  Bayesian methods to Neural Networks: The computation of the parton distribution functions (PDF) or distribution\namplitudes (DA) of hadrons from first principles lattice QCD constitutes a\ncentral open problem. In this study, we present and evaluate the efficiency of\na selection of methods for inverse problems to reconstruct the full\n$x$-dependence of PDFs. Our starting point are the so called Ioffe time PDFs,\nwhich are accessible from Euclidean time calculations in conjunction with a\nmatching procedure. Using realistic mock data tests, we find that the ill-posed\nincomplete Fourier transform underlying the reconstruction requires careful\nregularization, for which both the Bayesian approach as well as neural networks\nare efficient and flexible choices.",
        "positive": "String effects in Yang-Mills theory: We study some features of the confining string connecting a quark-anti-quark\npair in Yang-Mills theory. Monte Carlo investigations of the flux tube between\ntwo static quarks in the fundamental representation show that its thickness\nincreases with the separation of the sources. The collected numerical data in\n(2+1)-d SU(2) Yang-Mills theory are in very good quantitative agreement with\nthe next-to-leading order formula derived from the systematic low-energy\neffective theory of the confining string. At zero temperature, we observe the\npredicted logarithmic broadening. At finite and low temperature, the flux tube\nthickness is expected to broaden linearly. We also verify that prediction,\nfinding an excellent agreement with the analytic expression. No adjustable\nparameter has been used to fit the numerical data. Then we investigate the\nconfining strings connecting color sources in larger representations of the\ngauge group. Concerning stable strings -- the k-strings -- we study the Luscher\nterm of the fundamental string and of the 2-string in (2+1)-d SU(4) Yang-Mills\ntheory. We find that, at large separation between the two static sources, the\ncoefficient of the Luscher term of the 2-string appraoches the value -pi/24.\nHowever, at intermediate distances, there are relevant deviations. This result\nmay suggest that, for SU(N) at large N, a different intermediate string regime\ncould set in. For unstable strings, in (2+1)-d SU(2) Yang-Mills theory we\ninvestigate the decay between two different string states and the multiple\ndecays of the confining string connecting color sources in large\nrepresentations. The multiple decays result from the progressive partial\nscreening of the color sources."
    },
    {
        "anchor": "Renormalized couplings and scaling correction amplitudes in the N-vector\n  spin models on the sc and the bcc lattices: For the classical N-vector model, with arbitrary N, we have computed through\norder \\beta^{17} the high temperature expansions of the second field derivative\nof the susceptibility \\chi_4(N,\\beta) on the simple cubic and on the body\ncentered cubic lattices. (The N-vector model is also known as the O(N)\nsymmetric classical spin Heisenberg model or, in quantum field theory, as the\nlattice\n  O(N) nonlinear sigma model.) By analyzing the expansion of \\chi_4(N,\\beta) on\nthe two lattices, and by carefully allowing for the corrections to scaling, we\nobtain updated estimates of the critical parameters and more accurate tests of\nthe hyperscaling relation d\\nu(N) +\\gamma(N) -2\\Delta_4(N)=0 for a range of\nvalues of the spin dimensionality N, including\n  N=0 [the self-avoiding walk model], N=1 [the Ising spin 1/2 model],\n  N=2 [the XY model], N=3 [the classical Heisenberg model]. Using the recently\nextended series for the susceptibility and for the second correlation moment,\nwe also compute the dimensionless renormalized four point coupling constants\nand some universal ratios of scaling correction amplitudes in fair agreement\nwith recent renormalization group estimates.",
        "positive": "Investigation of spontaneous symmetry breaking from a non standard\n  approach: We propose a new method for the study of the chiral properties of the ground\nstate in Quantum Field Theories (QFT's) which is based on the computation of\nthe probability distribution function (p.d.f.) of the chiral condensate in the\nchiral limit. We show how despite of the fact that Grassmann variables cannot\nbe simulated on a computer, an analysis of spontaneous symmetry breaking\nwithout a symmetry breaking external field, which is standard in the case of\nspin systems, can also be done in QFT's with fermion degrees of freedom."
    },
    {
        "anchor": "The role of the double pole in lattice QCD with mixed actions: We investigate effects resulting from the use of different discretizations\nfor the valence and the sea quarks in lattice QCD, considering Wilson and/or\nGinsparg-Wilson fermions. We assume that such effects appear through scaling\nviolations that can be studied using effective lagrangian techniques. We show\nthat a double pole is present in flavor-neutral Goldstone meson\npropagators,even if the charged Goldstone mesons made out of valence quarks and\nthose made out of sea quarks have equal masses. We then consider some\nobservables known to be anomalously sensitive to the presence of a double pole.\nFor these observables, we find that the double-pole enhanced scaling violations\nmay turn out to be rather small in practice.",
        "positive": "Magnetic monopoles in high temperature QCD: We study the density and spatial distribution of thermal Abelian monopoles in\nthe deconfined phase of SU(2) pure gauge theory: they display non-trivial\ninteractions with a well defined continuum limit. The Maximal Abelian Gauge\n(MAG) has been chosen to perform the Abelian projection. Questions related to\nthe choice of the Abelian projection, as well as possible directions for future\nstudies, are discussed."
    },
    {
        "anchor": "New method for calculating electromagnetic effects in semileptonic\n  beta-decays of mesons: We construct several classes of hadronic matrix elements and relate them to\nthe low-energy constants in Chiral Perturbation Theory that describe the\nelectromagnetic effects in the semileptonic beta decay of the pion and the\nkaon. We propose to calculate them using lattice QCD, and argue that such a\ncalculation will make an immediate impact to a number of interesting topics at\nthe precision frontier, including the outstanding anomalies in $|V_{us}|$ and\nthe top-row Cabibbo-Kobayashi-Maskawa matrix unitarity.",
        "positive": "A lattice study of the exclusive $B \\to K^* \u03b3$ decay amplitude,\n  using the Clover action at $\u03b2=6.0$: We present the results of a numerical calculation of the $B\\to K^* \\gamma$\nform factors. The results have been obtained by studying the relevant\ncorrelation functions at $\\beta=6.0$, on an $18^3 \\times 64$ lattice, using the\n${\\rm O(a)}$-improved fermion action, in the quenched approximation. From the\nstudy of the matrix element $<K^*| \\bar s \\sigma_{\\mu\\nu} b | B>$ we have\nobtained the form factor $T_1(0)$ which controls the exclusive decay rate. The\nresults are compared with the recent results from CLEO. We also discuss the\ncompatibility between the scaling laws predicted by the Heavy Quark Effective\nTheory (HQET) and pole dominance, by studying the mass- and $q^2$-dependence of\nthe form factors. From our analysis, it appears that the form factors follow a\nmass behaviour compatible with the predictions of the HQET and that the\n$q^2$-dependence of $T_2$ is weaker than would be predicted by pole dominance."
    },
    {
        "anchor": "Loop-string-hadron formulation of an SU(3) gauge theory with dynamical\n  quarks: Towards the goal of quantum computing for lattice quantum chromodynamics, we\npresent a loop-string-hadron (LSH) framework in 1+1 dimensions for describing\nthe dynamics of SU(3) gauge fields coupled to staggered fermions. This novel\nframework was previously developed for an SU(2) lattice gauge theory in\n$d\\leq3$ spatial dimensions and its advantages for classical and quantum\nalgorithms have thus far been demonstrated in $d=1$. The LSH approach uses\ngauge invariant degrees of freedoms such as loop segments, string ends, and\non-site hadrons, it is free of all nonabelian gauge redundancy, and it is\ndescribed by a Hamiltonian containing only local interactions. In this work,\nthe SU(3) LSH framework is systematically derived from the reformulation of\nHamiltonian lattice gauge theory in terms of irreducible Schwinger bosons,\nincluding the addition of staggered quarks. Furthermore, the superselection\nrules governing the LSH dynamics are identified directly from the form of the\nHamiltonian. The SU(3) LSH Hamiltonian with open boundary conditions has been\nnumerically confirmed to agree with the completely gauge-fixed Hamiltonian,\nwhich contains long-range interactions and does not generalize to either\nperiodic boundary conditions or to $d>1$.",
        "positive": "Matrix elements of (delta S=2) operators with Wilson fermions: We test the recent proposal of using the Ward identities to compute the\nK0-K0bar mixing amplitude with Wilson fermions, without the problem of spurious\nlattice subtractions. From our simulations, we observe no difference between\nthe results obtained with and without subtractions. In addition, from the\nstandard study of the complete set of (delta S=2) operators, we quote the\nfollowing (preliminary) results (in the MS(NDR) scheme): Bk(2 GeV)=0.70(10), <\nO7^{3/2}>_{K->pi pi} = 0.10(2)(1) GeV^3, < O8^{3/2}>_{K->pi pi} = 0.49(6)(0)\nGeV^3."
    },
    {
        "anchor": "The Ginsparg-Wilson relation and local chiral random matrix theory: A chiral random matrix model with locality is constructed and examined. The\nNielsen-Ninomiya no-go theorem is circumvented by the use of a generally\napplicable modified Dirac operator which respects the Ginsparg-Wilson relation.\nWe observe the expected universal behaviour of the eigenvalue density in the\nmicroscopic limit.",
        "positive": "Supersymmetry on a Spatial Lattice: We construct a variety of supersymmetric gauge theories on a spatial lattice,\nincluding N=4 supersymmetric Yang-Mills theory in 3+1 dimensions. Exact lattice\nsupersymmetry greatly reduces or eliminates the need for fine tuning to arrive\nat the desired continuum limit in these examples."
    },
    {
        "anchor": "Semi-analytic calculation of the monopole order parameter in QCD: The monopole order parameter of QCD is computed in terms of gauge invariant\nfield strength correlators. Both quantities are partially known from numerical\nsimulations on the lattice. A new insight results on the structure of the\nconfining vacuum.",
        "positive": "Double parton distributions in the nucleon on the lattice: Flavor\n  interference effects: Information about double parton distributions (DPDs) can be obtained by\ncalculating four-point functions on the lattice. We continue our study on the\nfirst DPD Mellin moment of the unpolarized proton by considering interference\neffects w.r.t. the quark flavor. In our simulation we employ an $n_f = 2 + 1$\nensemble with inverse coupling $\\beta = 3.4$, and pseudoscalar masses of $m_\\pi\n= 355~\\mathrm{MeV}$ and $m_K = 441~\\mathrm{MeV}$. The results are converted to\nthe $\\overline{\\mathrm{MS}}$-scheme at the scale $\\mu = 2~\\mathrm{GeV}$. We\nanalyze the dependence of the considered Mellin moments on the quark\npolarization and compare our results with quark model predictions."
    },
    {
        "anchor": "Timelike pion form factor in lattice QCD: We perform a nonperturbative lattice calculation of the complex phase and\nmodulus of the pion form factor in the timelike momentum region using the\nfinite-volume technique. We use two ensembles of 2+1-flavor overlap fermion at\npion masses m_pi = 380 and 290 MeV. By calculating the I = 1 correlators in the\ncenter-of-mass and three moving frames, we obtain the form factor at ten\ndifferent values of the timelike momentum transfer around the vector resonance.\nWe compare the results with the phenomenological model of Gounaris-Sakurai and\nits variant.",
        "positive": "HQET at order $1/m$: II. Spectroscopy in the quenched approximation: Using Heavy Quark Effective Theory with non-perturbatively determined\nparameters in a quenched lattice calculation, we evaluate the splittings\nbetween the ground state and the first two radially excited states of the $B_s$\nsystem at static order. We also determine the splitting between first excited\nand ground state, and between the $B_s^*$ and $B_s$ ground states to order\n$1/m_b$. The Generalized Eigenvalue Problem and the use of all-to-all\npropagators are important ingredients of our approach."
    },
    {
        "anchor": "Non-perturbative renormalization of static-light four-fermion operators\n  in quenched lattice QCD: We perform a non-perturbative study of the scale-dependent renormalization\nfactors of a multiplicatively renormalizable basis of $\\Delta{B}=2$ parity-odd\nfour-fermion operators in quenched lattice QCD. Heavy quarks are treated in the\nstatic approximation with various lattice discretizations of the static action.\nLight quarks are described by non-perturbatively ${\\rm O}(a)$ improved\nWilson-type fermions. The renormalization group running is computed for a\nfamily of Schroedinger functional (SF) schemes through finite volume techniques\nin the continuum limit. We compute non-perturbatively the relation between the\nrenormalization group invariant operators and their counterparts renormalized\nin the SF at a low energy scale. Furthermore, we provide non-perturbative\nestimates for the matching between the lattice regularized theory and all the\nSF schemes considered.",
        "positive": "The pressure of the SU(N) lattice gauge theory at large-N: We calculate bulk thermodynamic properties, such as the pressure, energy\ndensity, and entropy, in SU(4) and SU(8) lattice gauge theories, for the range\nof temperatures T <= 2.0Tc and T <= 1.6Tc respectively. We find that the N=4,8\nresults are very close to each other, and to what one finds in SU(3), and are\nfar from the asymptotic free-gas value. We conclude that any explanation of the\nhigh-T pressure (or entropy) deficit must be such as to survive the N-->oo\nlimit. We give some examples of this constraint in action and comment on what\nthis implies for the relevance of gravity duals."
    },
    {
        "anchor": "The Massive Schwinger Model - a Hamiltonian Lattice Study in a Fast\n  Moving Frame: We present a non-perturbative study of the massive Schwinger model. We use a\nHamiltonian approach, based on a momentum lattice corresponding to a fast\nmoving reference frame, and equal time quantization. We present numerical\nresults for the mass spectrum of the vector and scalar particle. We find good\nagreement with chiral perturbation theory in the strong coupling regime and\nalso with other non-perturbative studies (Hamer et al., Mo and Perry) in the\nnon-relativistic regime. The most important new result is the study of the\n$\\theta$-action, and computation of vector and scalar masses as a function of\nthe $\\theta$-angle. We find excellent agreement with chiral perturbation\ntheory. Finally, we give results for the distribution functions. We compare our\nresults with Bergknoff's variational study from the infinite momentum frame in\nthe chiral region.",
        "positive": "Renormalization constants using quark states in Landau gauge: We show that given one O(a) improvement constant, b_m, all the remaining\nquantities needed to define the renormalized and O(a) improved dimension-3\nquark bilinears can be obtained by studying the matrix elements of these\noperators between external quark states in a fixed gauge."
    },
    {
        "anchor": "Three-body interactions from the finite-volume QCD spectrum: We perform a fit of the finite-volume QCD spectrum of three pions at maximal\nisospin to constrain the three-body force. We use the unitarity-based\nrelativistic three-particle quantization condition, with the GWUQCD spectrum\nobtained at 315 MeV and 220 MeV pion mass in two-flavor QCD. For the heavier\npion mass we find that the data is consistent with a constant contact term\nclose to zero, whereas for the lighter mass we see a statistically significant\nenergy dependence in tension with the prediction of leading order ChPT. Our\nresults also suggest that with enough three-body energy levels, the two-body\namplitude could be constrained.",
        "positive": "Lattice chiral symmetry, Yukawa couplings and the Majorana condition: It is shown that the conflict between lattice chiral symmetry and the\nMajorana condition in the presence of Yukawa couplings, which was noted in our\nprevious paper, is related in an essential way to the basic properties of\nGinsparg-Wilson operators, namely, locality and species doubling."
    },
    {
        "anchor": "Single massless Majorana fermion in the domain-wall formalism: We study the domain-wall formalism with additional Majorana mass term for the\nunwanted zero mode, which has recently been proposed for lattice construction\nof 4D N=1 super Yang-Mills theory without fine-tuning. Switching off the gauge\nfield, we study the dispersion relation of the energy eigenstates numerically,\nand find that the method works for reasonable values of Majorana mass. We point\nout, however, that a problem arises for too large Majorana mass, which can be\nunderstood in terms of the seesaw mechanism.",
        "positive": "Spectroscopy of charmed baryons from lattice QCD: We present the ground and excited state spectra of singly, doubly and triply\ncharmed baryons by using dynamical lattice QCD. A large set of baryonic\noperators that respect the symmetries of the lattice and are obtained after\nsubduction from their continuum analogues are utilized. Using novel\ncomputational techniques correlation functions of these operators are generated\nand the variational method is exploited to extract excited states. The lattice\nspectra that we obtain have baryonic states with well-defined total spins up to\n7/2 and the low lying states remarkably resemble the expectations of quantum\nnumbers from SU(6) $\\otimes$ O(3) symmetry. Various energy splittings between\nthe extracted states, including splittings due to hyperfine as well as\nspin-orbit coupling, are considered and those are also compared against similar\nenergy splittings at other quark masses."
    },
    {
        "anchor": "Meson correlation functions at high temperatures: We present preliminary results for the correlation- and spectral functions of\ndifferent meson channels on the lattice. The main focus lies on gaining control\nover cut-off as well as on the finite-volume effects. Extrapolations of\nscreening masses above the deconfining temperature are guided by the result of\nthe free ($T=\\infty$) case on the lattice and in the continuum. We study the\nquenched non-perturbatively improved Wilson-clover fermion as well as the\nhypercube fermion action which might show less cut-off effects.",
        "positive": "Monopole action from vacuum configurations in compact QED: It is possible to derive a monopole action from vacuum configurations\nobtained in Monte-Carlo simulations extending the method developed by Swendsen.\nWe apply the method to compact QED both in the Villain and in the Wilson forms.\nThe action of the natural monopoles in the Villain case is in fairly good\nagreement with that derived by the exact dual transformation. Comparing the\nmonopole actions, we find (1) the DeGrand-Toussaint monopole definition may be\nuseful for $\\beta_V $ larger than about 0.5, (2) the Villain model well\napproximates the Wilson one for $\\beta$ smaller than $\\beta_c$ and (3) in the\nWilson action the monopole condensation occurs in the confinement phase and\n$\\beta_c$ may be explained by the energy-entropy balance of monopole loops like\nin the Villain case."
    },
    {
        "anchor": "Strong randomness of off-diagonal gluon phases and off-diagonal gluon\n  mass in the maximally abelian gauge in QCD: We study abelianization of QCD in the maximally abelian (MA) gauge. In the MA\ngauge, the off-diagonal gluon amplitude is strongly suppressed, and then the\noff-diagonal gluon phase shows strong randomness, which leads to a large\noff-diagonal gluon mass. Using lattice QCD, we find a large effective\noff-diagonal gluon mass in the MA gauge: $M_{\\rm off} \\simeq 1.2 {\\rm GeV}$ in\nSU(2) QCD, $M_{\\rm off} \\simeq 1.1 {\\rm GeV}$ in SU(3) QCD. Due to the large\noff-diagonal gluon mass in the MA gauge, infrared QCD is well abelianized like\nnonabelian Higgs theories. We investigate the inter-monopole potential and the\ndual gluon field $B_\\mu$ in the MA gauge, and find longitudinal magnetic\nscreening with $m_B \\simeq$ 0.5 GeV in the infrared region, which indicates the\ndual Higgs mechanism by monopole condensation. We propose a gauge invariant\ndescription of the MA projection by introducing the ``gluonic Higgs scalar\nfield''.",
        "positive": "Pion-pion scattering and the timelike pion form factor from\n  $N_{\\mathrm{f}} = 2+1$ lattice QCD simulations using the stochastic LapH\n  method: We report on progress applying the stochastic LapH method to estimate\nall-to-all propagators required in correlation functions of multi-hadron\noperators relevant for pion-pion scattering. Large-volume results for $I=2$ and\n$I=1$ pion-pion scattering phase shifts with good statistical precision are\nobtained from an $N_{\\rm f} = 2+1$ anisotropic Wilson clover ensemble with\n$m_{\\pi} = 240\\mathrm{MeV}$. We also present a preliminary determination of the\n$I=1$ pion-pion scattering phase shift and timelike pion form factor on an\nisotropic $N_{\\rm f}=2+1$ flavour ensemble generated by the Coordinated Lattice\nSimulation (CLS) community effort."
    },
    {
        "anchor": "Goldstone-mode effects and scaling function for the three-dimensional\n  O(4) model: We investigate numerically the three-dimensional O(4) model on 24^3-120^3\nlattices as a function of the magnetic field H. We verify explicitly the\nsingularities induced by Goldstone modes in the low-temperature phase of the\nmodel, and show that they are also observed close to the critical temperature.\nOur results are well described by the perturbative form of the model's magnetic\nequation of state, with coefficients determined nonperturbatively from our\ndata. The resulting expression is used to generate the magnetization's scaling\nfunction parametrically.",
        "positive": "Search for Z_c^+(3900) in the 1^+- channel on the lattice: Recently three experiments reported a discovery of manifestly exotic\nZ_c^+(3900) in the decay to J/psi pi+, while J and P are experimentally\nunknown. We search for this state on the lattice by simulating the channel with\nJ^PC=1^+- and I=1, and we do not find a candidate for Z_c^+(3900). Instead, we\nonly find discrete scattering states D D* and J/psi pi, which inevitably have\nto be present in a dynamical QCD. The possible reasons for not finding $Z_c^+$\nmay be that its quantum numbers are not $1^{+-}$ or that the employed\ninterpolating fields are not diverse enough. Simulations with additional types\nof interpolators will be needed to reach a more definite conclusion."
    },
    {
        "anchor": "Fifty ways to build a deuteron: a variational calculation of two-nucleon\n  systems: A variational study of two-nucleon systems with lattice quantum\nchromodynamics is performed using a wide range of interpolating operators:\ndibaryon operators built from products of momentum-projected nucleons,\nhexaquark operators built from six spatially localized quarks, and quasi-local\noperators inspired by two-nucleon bound-state wavefunctions in nuclear\neffective field theories. Correlation-function matrices involving products of\nthese operators are constructed by computing timeslice-to-all quark propagators\nwith sparsening techniques. Comparisons between results obtained using the same\ngauge-field ensemble but different interpolating-operator sets demonstrate that\ninterpolating-operator dependence can lead to significant effects on the\ntwo-nucleon energy spectra obtained using both variational and non-variational\nmethods.",
        "positive": "Winding expansion techniques for lattice QCD with chemical potential: We analytically derive a decomposition of the lattice fermion determinant for\nWilson's Dirac operator with chemical potential into winding sectors, i.e.,\nfactors with a fixed number of quarks. Dividing the lattice into four domains,\nthe determinant is factorized into terms which can be classified with respect\nto the winding number of the closed loops they consist of. The individual\nfactors are expressed in terms of subdeterminants and propagators on the\ndomains of the lattice. We numerically analyze properties of the factorization\nformula and discuss two applications for the determination of canonical\npartition functions with a fixed quark number: A speedup for the Fourier\ntransformation technique through a dimensional reduction, and a power series\nexpansion."
    },
    {
        "anchor": "Advances in using density of states for large-N Yang--Mills: We present work in progress using the Logarithmic Linear Relaxation (LLR)\ndensity of states algorithm to analyse first-order phase transitions in\npure-gauge SU(N) Yang--Mills theories, focusing on N = 4 and 6. By using the\nLLR algorithm we aim to avoid super-critical slowing down at such transitions.\nMotivation for this study comes from composite dark matter models, which may\nfeature a first-order confinement transition in the early Universe that would\nproduce a background of gravitational waves. Improving our understanding of\nthese phase transitions will help probe these models using observations from\nfuture gravitational-wave observatories. In addition to the confinement\ntransition, we also analyze bulk phase transitions of the lattice theories,\nwhich feature much larger latent heat.",
        "positive": "Infrared Maximally Abelian Gauge: The confinement scenario in Maximally Abelian gauge (MAG) is based on the\nconcepts of Abelian dominance and of dual superconductivity. Recently, several\ngroups pointed out the possible existence in MAG of ghost and gluon condensates\nwith mass dimension 2, which in turn should influence the infrared behavior of\nghost and gluon propagators. We present preliminary results for the first\nlattice numerical study of the ghost propagator and of ghost condensation for\npure SU(2) theory in the MAG."
    },
    {
        "anchor": "Nonperturbative excitations in overoccupied gluon plasmas: Motivated by the early-time dynamics of the quark-gluon plasma in high-energy\nheavy-ion collisions, we extract gluonic spectral functions of overoccupied\ngauge theories far from equilibrium using classical-statistical lattice\nsimulations and linear response theory. In 3+1 dimensions we find that the\nspectral function exhibits quasiparticle excitations at all momenta that are\nmostly consistent with perturbative hard-thermal loop predictions, while\npartially showing nonperturbative deviations. In contrast, the structure of\nexcitations in 2+1 dimensions is nontrivial and nonperturbative. These\nnonperturbative interactions lead to broad excitation peaks in the spectral\nfunction, demonstrating the absence of soft quasiparticles in these theories.\nThis also suggests that there may be significant nonperturbative corrections\npresent in systems with large momentum anisotropy, which are relevant to\nphenomenological applications in heavy-ion collisions.",
        "positive": "First study of twist-3 PDFs for the proton from lattice QCD: In these proceedings, we summarize the main results from the first-ever\ncalculations of the chiral-even and chiral-odd twist-3 parton distributions,\n$g_T(x)$ and $h_L(x)$, of the proton from lattice QCD. We use an $N_f=2+1+1$\nensemble of maximally twisted mass fermions with a clover improvement. The\nlattice has a spatial extent of 3~fm, the lattice spacing is 0.093~fm, and the\npion mass is $260$~MeV. The matrix elements are obtained with a source-sink\ntime separation of 1.12~fm to control contamination from excited states. The\ncalculation is based on the quasi-PDF approach and employs three values for the\nproton momentum: 0.83~GeV, 1.25~GeV, and 1.67~GeV. The lattice data are\nrenormalized non-perturbatively using the RI$'$ scheme, and the final results\nare presented in the $\\overline{\\rm MS}$ scheme at the scale of 2~GeV.\nFurthermore, we compute in the same setup the helicity, $g_1(x)$, and\ntransversity, $h_1(x)$, distributions, which are used to compare $g_T(x)$ and\n$h_L(x)$ to their Wandzura-Wilczek approximations. For $h_L(x)$, we combine\nresults for the isovector and isoscalar flavor combinations to disentangle the\nindividual up- and down-quark contributions."
    },
    {
        "anchor": "Is the Graviton a Domain Wall Glueball?: Strong coupling calculations for the glueball spectrum in an $AdS^7$ black\nhole are modified by introducing an UV cut-off at a Planck brane. A new\nnormalizable state in the tensor spectrum is found which reproduces\nEinstein-Hilbert gravity up to exponentially small corrections due to off shell\nmixing with massive glueballs.",
        "positive": "Calculation of free baryon spectral densities at finite temperature: Following a recent lattice study of nucleon parity doubling at finite\ntemperature from the computation of the two-point nucleon correlators, we study\nthe spectral functions of free nucleons at finite temperature. Spectral\ndensities in the continuum are presented along with a comparison to (free)\nresults on the lattice. Particular attention is given to lattice artefacts at\nhigher energies."
    },
    {
        "anchor": "Leptonic decay constants for D-mesons from 3-flavour CLS ensembles: We report on the status of an ongoing effort by the RQCD and ALPHA\nCollaborations, aimed at determining leptonic decay constants of charmed\nmesons. Our analysis is based on large-volume ensembles generated within the\nCLS effort, employing N_f=2+1 non-perturbatively O(a) improved Wilson quarks,\ntree-level Symanzik-improved gauge action and open boundary conditions. The\nensembles cover lattice spacings from a ~ 0.09 fm to a ~ 0.05 fm, with pion\nmasses varied from 420 to 200 MeV. To extrapolate to the physical masses, we\nfollow both the 2m_l+m_s=const. and the m_s=const. lines in parameter space.",
        "positive": "Critical end point of Nf=3 QCD at finite temperature and density: We investigate the phase structure of 3-flavor QCD in the presence of finite\nquark chemical potential $a\\mu=0.1$ by using the Wilson-Clover fermion action.\nEspecially, we focus on locating the critical end point that characterizes the\nphase structure. We do this by the kurtosis intersection method for the quark\ncondensate. For Wilson-type fermions, the correspondence between bare\nparameters and physical parameters is indirect. Hence we present a strategy to\ntransfer the bare parameter phase structure to the physical one."
    },
    {
        "anchor": "Extraction of isoscalar $\u03c0\u03c0$ phase-shifts from lattice QCD: We conduct a two-flavor ($N_f=2$) lattice QCD calculation of the elastic\nphase-shifts for pion-pion scattering in the scalar, isoscalar channel (the\n$\\sigma$-meson). The calculation is performed for two quark masses\ncorresponding to a pion mass of $315\\text{ MeV}$ and $227\\text{ MeV}$. The\n$\\sigma$-meson parameters are extracted using various parametrizations of the\nscattering amplitude. The results obtained from a chiral unitary\nparametrization are extrapolated to the physical point and read $M_\\sigma =\n(440^{+10}_{-16}(50) - i\\,240(20)(25))\\text{ MeV}$, where the uncertainties in\nthe parentheses denote the stochastic and systematic ones. The behavior of the\n$\\sigma$-meson parameters with increasing pion mass is discussed as well.",
        "positive": "The impact of localized overlap eigenmodes on RMT measurements and\n  topology: The low energy eigenmodes of the continuum QCD Dirac operator are extended,\nbut on the lattice, due to discretization effects, the Dirac operator can have\nlocalized eigenmodes. These non-physical modes can introduce strong lattice\nartifacts for observables that are sensitive to chiral symmetry, especially in\nmixed action simulations. We study how these lattice artifacts depend on the\nparameters of the overlap operator and their affect on the distribution on the\nDirac eigenmodes and the topological susceptibility."
    },
    {
        "anchor": "Numerical study of the relativistic three-body quantization condition in\n  the isotropic approximation: We present numerical results showing how our recently proposed relativistic\nthree-particle quantization condition can be used in practice. Using the\nisotropic (generalized $s$-wave) approximation, and keeping only the leading\nterms in the effective range expansion, we show how the quantization condition\ncan be solved numerically in a straightforward manner. In addition, we show how\nthe integral equations that relate the intermediate three-particle\ninfinite-volume scattering quantity, $\\mathcal K_{\\text{df},3}$, to the\nphysical scattering amplitude can be solved at and below threshold. We test our\nmethods by reproducing known analytic results for the $1/L$ expansion of the\nthreshold state, the volume dependence of three-particle bound-state energies,\nand the Bethe-Salpeter wavefunctions for these bound states. We also find that\ncertain values of $\\mathcal K_{\\text{df},3}$ lead to unphysical finite-volume\nenergies, and give a preliminary analysis of these artifacts.",
        "positive": "Hidden Conformal Symmetry from Eight Flavors: This proceedings paper extends the scope of our conference talk, where we\npresented a comprehensive analysis of newly expanded and refined lattice data\nconcerning the SU(3) gauge theory with Nf = 8 light Dirac fermions - a theory\npositioned near the conformal window boundary. The analysis presented here\nmakes use of a dilaton effective field theory and we delve deeper into the\nintricacies of the dilaton potential. We aim to clarify the connection between\nparameters appearing the potential and properties of the underlying gauge\ntheory."
    },
    {
        "anchor": "A non-perturbative estimate of the heavy quark momentum diffusion\n  coefficient: We estimate the momentum diffusion coefficient of a heavy quark within a pure\nSU(3) plasma at a temperature of about 1.5Tc. Large-scale Monte Carlo\nsimulations on a series of lattices extending up to 192^3*48 permit us to carry\nout a continuum extrapolation of the so-called colour-electric imaginary-time\ncorrelator. The extrapolated correlator is analyzed with the help of\ntheoretically motivated models for the corresponding spectral function.\nEvidence for a non-zero transport coefficient is found and, incorporating\nsystematic uncertainties reflecting model assumptions, we obtain kappa = (1.8 -\n3.4)T^3. This implies that the \"drag coefficient\", characterizing the time\nscale at which heavy quarks adjust to hydrodynamic flow, is (1.8 - 3.4)\n(Tc/T)^2 (M/1.5GeV) fm/c, where M is the heavy quark kinetic mass. The results\napply to bottom and, with somewhat larger systematic uncertainties, to charm\nquarks.",
        "positive": "Two-dimensional lattice SU($N_c$) gauge theories with multiflavor\n  adjoint scalar fields: We consider two-dimensional lattice SU($N_c$) gauge theories with $N_f$ real\nscalar fields transforming in the adjoint representation of the gauge group and\nwith a global O($N_f$) invariance. Focusing on systems with $N_f\\ge 3$, we\nstudy their zero-temperature limit, to understand under which conditions a\ncontinuum limit exists, and to investigate the nature of the associated quantum\nfield theory. Extending previous analyses, we address the role that the\ngauge-group representation and the quartic scalar potential play in determining\nthe nature of the continuum limit (when it exists). Our results further\ncorroborate the conjecture that the continuum limit of two-dimensional lattice\ngauge models with multiflavor scalar fields, when it exists, is associated with\na $\\sigma$ model defined on a symmetric space that has the same global symmetry\nas the lattice model."
    },
    {
        "anchor": "Anisotropic lattice QCD study of pentaquark baryons in spin 3/2 channel: We perform the comprehensive analysis of the pentaquark (5Q) in J^P=3/2^{\\pm}\nchannel using anisotropic quenched lattice QCD. We employ the standard Wilson\ngauge action at \\beta=5.75 and the O(a) improved Wilson (clover) quark action\non a 12^3*96 lattice with the renormalized anisotropy as a_s/a_t = 4. A large\nnumber of gauge configurations as Nconf=1000 is analyzed, which is found to be\nessential to achieve a reliable measurement. We study three types of the\nRarita-Schwinger intepolationg fields with I=0: (a) the NK*-type, (b) the\n(color-)twisted NK*-type, (c) a diquark-type. As a result, we find only massive\nstates as m(5Q)= 2.1-2.2 GeV in J^P=3/2^- channel, and m(5Q) = 2.4-2.6 GeV in\nJ^P=3/2^+ channel in the chiral limit. The analysis with the hybrid boundary\ncondition (HBC) is performed to distinguish whether these resonances are\ncompact 5Q resonances or two-particle scattering states. No low-lying compact\n5Q resonance states are found below 2.1GeV.",
        "positive": "Axial and electromagnetic observables of hyperons in 2-flavor chiral\n  perturbation theory: Two-flavor chiral expansions provide a useful perturbative framework to study\nhadron properties. Such expansions should exhibit marked improvement over the\nconventional three-flavor chiral expansion. Although in principle one can\nformulate two-flavor theories for the various hyperon multiplets, the nearness\nof kaon thresholds can seriously undermine the effectiveness of such two-flavor\ntheories in practice. We investigate the importance of virtual kaon thresholds\non hyperon properties, specifically their isovector axial charges and\nelectromagnetic observables. In particular we uncover the underlying expansion\nparameter governing the description of virtual kaon thresholds. For spin-half\nhyperons, this expansion parameter is under theoretical control. As a result,\nthe virtual kaon contributions are well described in the two-flavor theory by\nterms analytic in the pion mass-squared. For spin three-half hyperons, however,\none is closer to the kaon production threshold, and the expansion parameter is\nnot as small. Breakdown of $SU(2)$ chiral perturbation theory is shown to arise\nfrom a pole in the expansion parameter associated with the kaon threshold. We\nfind that, despite the fact that higher-order corrections to the expansion\nparameter is necessary to ascertain whether the two-flavor theory of spin\nthree-half hyperons remains perturbative, there is a useful perturbative\nexpansion for isovector axial charges and magnetic moments of both spin-half\nand spin three-half hyperons."
    },
    {
        "anchor": "Hybrid Exotic Meson Decay Width: We present results of a decay width calculation for a hybrid exotic meson(h,\nJPC=1-+) in the decay channel h to pi+a1. This calculation uses quenched\nlattice QCD and Luescher's finite box method. Operators for the h and pi+a1\nstates are used in a correlation matrix which was expanded by varying the\nsmearing and fuzzing levels at source and sink points. Scattering phase shifts\nfor a discrete set of relative pi+a1 momenta are determined using eigenvalues\nof the correlation matrix and formulae derived by Luescher. The phase shift\ndata is very sparse, but fits to a Breit-Wigner model are made, resulting in a\ndecay width of about 80 MeV.",
        "positive": "Scattering of Glueballs and Mesons in Compact $QED$ in $2+1$ Dimensions: We study glueball and meson scattering in compact $QED_{2+1}$ gauge theory in\na Hamiltonian formulation and on a momentum lattice. We compute ground state\nenergy and mass, and introduce a compact lattice momentum operator for the\ncomputation of dispersion relations. Using a non-perturbative time-dependent\nmethod we compute scattering cross sections for glueballs and mesons. We\ncompare our results with strong coupling perturbation theory."
    },
    {
        "anchor": "Lattice QCD with the Overlap-Dirac Operator: Its $\u039b$ Parameter,\n  and One-Loop Renormalization of Fermionic Currents: We compute the ratio between the scale $\\Lambda_L$ associated with a lattice\nformulation of QCD using the overlap-Dirac operator, and $\\Lambda_{MS-bar}$. To\nthis end, the one-loop relation between the lattice coupling $g_0$ and the\ncoupling renormalized in the MS-bar scheme is calculated, using the lattice\nbackground field technique.\n  We also compute the one-loop renormalization $Z_\\Gamma$ of the two-quark\noperators $\\bar{\\psi} \\Gamma \\psi$, where $\\Gamma$ denotes a generic Dirac\nmatrix. Furthermore, we study the renormalization of quark bilinears which are\nmore extended and have better chiral properties.\n  Finally, we present improved estimates of $Z_\\Gamma$, coming from cactus\nresummation and from mean field perturbation theory.",
        "positive": "Dyons and Roberge - Weiss transition in lattice QCD: We study lattice QCD with $N_f=2$ Wilson fermions at nonzero imaginary\nchemical potential and nonzero temperature. We relate the Roberge - Weiss phase\ntransition to the properties of dyons which are constituents of the KvBLL\ncalorons. We present numerical evidence that the characteristic features of the\nspectral gap of the overlap Dirac operator as function of an angle modifying\nthe boundary condition are determined by the $Z_3$ sector of the respective\nimaginary chemical potential. We then demonstrate that dyon excitations in\nthermal configurations could be responsible (in line with perturbative\nexcitations) for these phenomena."
    },
    {
        "anchor": "Light Hadron Weak Matrix Elements: Recent developments in lattice QCD calculation of weak matrix elements\ninvolving light quarks are described. We focus on four topics: $B_K$ with the\nKogut-Susskind and Wilson quark actions, $\\Delta I=1/2$ rule, proton decay\nmatrix elements and the application of domain wall QCD to calculation of weak\nmatrix elements.",
        "positive": "Perturbative renormalization factors for bilinear and four-quark\n  operators for Kogut-Susskind fermions on the lattice: Renormalization factors for bilinear and four-quark operators with the\nKogut-Susskind fermion action are perturbatively calculated to one-loop order\nin the general covariant gauge. Results are presented both for gauge invariant\nand non-invariant operators. For four-quark operators the full renormalization\nmatrix for a complete set of operators with two types of color contraction\nstructures are worked out and detailed numerical tables are given."
    },
    {
        "anchor": "Monte Carlo Study of 8-State Potts Model on 2D Random Lattices: We study the effect of quenched coordination-number disorder of random\nlattices on the nature of the phase transition in the two-dimensional\neight-state Potts model, which is of first order on regular lattices. We\nconsider Poissonian random lattices of toroidal topology constructed according\nto the Voronoi/Delaunay prescription. Monte Carlo simulations yield strong\nevidence that the phase transition remains first order.",
        "positive": "Chiral zero modes on the domain-wall model in 4+1 dimensions: We investigate an original domain-wall model in 4+1 dimensions numerically in\nthe presence of U(1) dynamical gauge field only in an extra dimension,\ncorresponding to a weak coupling limit of 4-dimensional physical gauge\ncoupling. Using a quenched approximation we carry out numerical simulation for\nthis model at $\\beta_{s} (= 1 / g^{2}_{s}) =$ 0.29 (``symmetric'' phase) and\n0.5 (``broken'' phase), where $g_s$ is the gauge coupling constant of the extra\ndimension. In the broken phase, we found that there exists a critical value of\na domain-wall mass $m_{0}^{c}$ which separates a region with a fermionic zero\nmode on the domain wall from the one without it in the same case of\n(2+1)-dimensional model. On the other hand, in the symmetric phase, our\nnumerical data suggest that the chiral zero modes disappear in the infinite\nlimit of 4-dimensional volume. From these results it seems difficult to\nconstruct the U(1) lattice chiral gauge theory via an original domain-wall\nformulation."
    },
    {
        "anchor": "Large N QCD -- Continuum reduction and chiral condensate: Continuum reduction in large N QCD enables one to extract physical quantities\nin the $N\\to\\infty$ limit of QCD by working in small physics volumes. The\ncomputation of chiral condensate is an example of such a calculation.",
        "positive": "Moving from continuous to discrete symmetry in the 2D XY model: We study the effects of discretization on the U(1) symmetric XY model in two\ndimensions using the Higher Order Tensor Renormalization Group (HOTRG)\napproach. Regarding the $Z_N$ symmetric clock models as specific\ndiscretizations of the XY model, we compare those discretizations to ones from\ntruncations of the tensor network formulation of the XY model based on a\ncharacter expansion, and focus on the differences in their phase structure at\nlow temperatures. We also divide the tensor network formulations into core and\ninteraction tensors and show that the core tensor has the dominant influence on\nthe phase structure. Lastly, we examine a perturbed form of the XY model that\ncontinuously interpolates between the XY and clock models. We examine the\nbehavior of the additional phase transition caused by the perturbation as the\nmagnitude of perturbation is taken to zero. We find that this additional\ntransition has a non-zero critical temperature as the perturbation vanishes,\nsuggesting that even small perturbations can have a significant effect on the\nphase structure of the theory."
    },
    {
        "anchor": "Structure functions near the chiral limit: We compute hadron masses and the lowest moments of unpolarized and polarized\nnucleon structure functions down to pion masses of 300 MeV, in an effort to\nmake unambiguous predictions at the physical light quark mass.",
        "positive": "Toward an analytic determination of the deconfinement temperature in\n  SU(2) L.G.T.: We consider the SU(2) lattice gauge theory at finite temperature in (d+1)\ndimensions, with different couplings $\\beta_t$ and $\\beta_s$ for timelike and\nspacelike plaquettes. By using the character expansion of the Wilson action and\nperforming the integrals over space-like link variables, we find an effective\naction for the Polyakov loops which is exact to all orders in $\\beta_t$ and to\nthe first non-trivial order in $\\beta_s$. The critical coupling for the\ndeconfinement transition is determined in the (3+1) dimensional case, by the\nmean field method, for different values of the lattice size $N_t$ in the\ncompactified time direction and of the asymmetry parameter $\\rho =\n\\sqrt{\\beta_t/\\beta_s}$. We find good agreement with Montecarlo simulations in\nthe range $1\\leq N_t \\leq 5$, and good qualitative agreement in the same range\nwith the logarithmic scaling law of QCD. Moreover the dependence of the results\nfrom the parameter $\\rho$ is in excellent agreement with previous theoretical\npredictions."
    },
    {
        "anchor": "Electric Polarizability of Neutral Hadrons from Lattice QCD: By simulating a uniform electric field on a lattice and measuring the change\nin the rest mass, we calculate the electric polarizability of neutral mesons\nand baryons using the methods of quenched lattice QCD. Specifically, we measure\nthe electric polarizability coefficient from the quadratic response to the\nelectric field for 10 particles: the vector mesons $\\rho^0$ and $K^{*0}$; the\noctet baryons n, $\\Sigma^0$, $\\Lambda_{o}^{0}$, $\\Lambda_{s}^{0}$, and $\\Xi^0$;\nand the decouplet baryons $\\Delta^0$, $\\Sigma^{*0}$, and $\\Xi^{*0}$.\nIndependent calculations using two fermion actions were done for consistency\nand comparison purposes. One calculation uses Wilson fermions with a lattice\nspacing of $a=0.10 $fm. The other uses tadpole improved L\\\"usher-Weiss gauge\nfields and clover quark action with a lattice spacing $a=0.17 $fm. Our results\nfor neutron electric polarizability are compared to experiment.",
        "positive": "Isospin Breaking Corrections to the HVP with Domain Wall Fermions: We present results for the QED and strong isospin breaking corrections to the\nhadronic vacuum polarization using $N_f=2+1$ Domain Wall fermions. QED is\nincluded in an electro-quenched setup using two different methods, a stochastic\nand a perturbative approach. Results and statistical errors from both methods\nare directly compared with each other."
    },
    {
        "anchor": "Gribov Copies in the Minimal Landau Gauge: the Influence on Gluon and\n  Ghost Propagators: We study the influence of Gribov copies on gluon and ghost propagators,\nevaluated numerically in pure SU(2) lattice gauge theory in the minimal Landau\ngauge. Simulations are done at four different values of $\\beta$ (namely $\\beta$\n= 0, 0.8, 1.6 and 2.7) and for volumes up to $16^4$ (up to $24^4$ at $\\beta$ =\n1.6). For the gluon propagator, Gribov noise seems to be of the order of\nmagnitude of the numerical accuracy, even at very small values of the coupling\n$\\beta$. On the contrary, for the ghost propagator, Gribov noise is clearly\nobservable for the three values of $\\beta$ in the strong-coupling regime. In\nparticular, data corresponding to the minimal Landau gauge are always smaller\nthan those obtained in a generic Landau gauge. This result can be qualitatively\nexplained.",
        "positive": "Deep learning study on the Dirac eigenvalue spectrum of staggered quarks: We study the chirality of staggered quarks on the Dirac eigenvalue spectrum\nusing deep learning (DL) techniques. The Kluberg-Stern method to construct\nstaggered bilinear operators conserves continuum property such as recursion\nrelations, uniqueness of chirality, and Ward identities, which leads to a\nunique and characteristic pattern (we call it \"leakage pattern (LP)\") in the\nmatrix elements of the chirality operator sandwiched between two quark\neigenstates of staggered Dirac operator. DL analysis gives $99.4(2)\\%$ accuracy\non normal gauge configurations and $0.998$ AUC (Area Under ROC Curve) for\nclassifying non-zero mode octets in the Dirac eigenvalue spectrum. It confirms\nthat the leakage pattern is universal on normal gauge configurations. The\nmulti-layer perceptron (MLP) method turns out to be the best DL model for our\nstudy on the LP."
    },
    {
        "anchor": "QCD, monopoles on the Lattice and gauge invariance: The number and the location of the monopoles observed on the lattice in QCD\nconfigurations happens to depend strongly on the choice of the gauge used to\nexpose them, in contrast to the physical expectation that monopoles be gauge\ninvariant objects. It is proved by use of the non abelian Bianchi identities\n(NABI) that monopoles are indeed gauge invariant, but the method used to detect\nthem depends, in a controllable way, on the choice of the abelian projection.\nNumerical checks are presented.",
        "positive": "Complex Langevin simulation in condensed matter physics: The complex Langevin method is one hopeful candidate to tackle the sign\nproblem. This method is applicable not only to QCD but also to nonrelativistic\nfield theory, such as condensed matter physics. We present the simulation\nresults of a rotating Bose gas and an imbalanced Fermi-Hubbard model."
    },
    {
        "anchor": "Anomalies and chiral defect fermions: Chiral defect fermions in the background of an external, $2n$ dimensional\ngauge field are considered. Assuming first a finite extra dimension, we\ncalculate the axial anomaly in a vector-like, gauge invariant model for\narbitrary $n$, and the consistent anomaly in a gauge {\\it variant} model with a\nchiral spectrum. For technical reasons, the latter calculation is limited to\nthe $2+1$ dimensional case. We also show that the infinite lattice chiral\nmodel, when properly defined, is in fact a limiting case of the above\ngauge-variant model. The behaviour of this model with a dynamical gauge field\nis discussed.",
        "positive": "Searching for dynamical fermion effects in UKQCD simulations: We present recent results from the UKQCD collaboration's dynamical QCD\nsimulations. This data has fixed lattice spacing but varying dynamical quark\nmass. We concentrate on searching for an unquenching signal in the mesonic mass\nspectrum where we do not find a significant effect at the quark masses\nconsidered."
    },
    {
        "anchor": "Towards the determination of the charm quark mass on $N_\\mathrm{f}=2+1$\n  CLS ensembles: We present the current status of our lattice QCD determination of the charm\nquark mass using $N_\\mathrm{f}=2+1$ dynamical, non-perturbatively\n$\\mathrm{O}(a)$ improved Wilson fermions. A subset of CLS ensembles with five\ndifferent lattice spacings along the $\\mathrm{Tr}[M_\\mathrm{q}]=\\text{const.}$\ntrajectory is used. For the computation of the correlation functions involving\nvalence charm quark propagators, we employ distance preconditioning to gain the\nnecessary precision. To stabilize the extrapolations to the physical point, we\nconsider different definitions of the bare charm quark mass and corresponding\nrenormalization procedures.",
        "positive": "Flavor structure of $\u039b$ baryons from lattice QCD: From strange to\n  charm quarks: We study $\\Lambda$ baryons of spin-parity $\\frac{1}{2}^{\\pm}$ with either a\nstrange or charm valence quark in full 2+1 flavor lattice QCD. Multiple $SU(3)$\nsinglet and octet operators are employed to generate the desired single baryon\nstates on the lattice. Via the variational method, the couplings of these\nstates to the different operators provide information about the flavor\nstructure of the $\\Lambda$ baryons. We make use of the gauge configurations of\nthe PACS-CS Collaboration and chirally extrapolate the results for the masses\nand $SU(3)$ flavor components to the physical point. We furthermore gradually\nchange the hopping parameter of the heaviest quark from strange to charm to\nstudy how the properties of the $\\Lambda$ baryons evolve as a function of the\nheavy quark mass. It is found that the baryon energy levels increase almost\nlinearly with the quark mass. Meanwhile, the flavor structure of most of the\nstates remains stable, with the exception of the lowest $\\frac{1}{2}^{-}$\nstate, which changes from a flavor singlet $\\Lambda$ to a $\\Lambda_c$ state\nwith singlet and octet components of comparable size. Finally, we discuss\nwhether our findings can be interpreted with the help of a simple quark model\nand find that the negative-parity $\\Lambda_c$ states can be naturally explained\nas diquark excitations of the light $u$ and $d$ quarks. On the other hand, the\nquark-model picture does not appear to be adequate for the negative-parity\n$\\Lambda$ states, suggesting the importance of other degrees of freedom to\ndescribe them."
    },
    {
        "anchor": "Quantum variational approach to lattice gauge theory at nonzero density: The simulation of dense fermionic matters is a long-standing problem in\nlattice gauge theory. One hopeful solution would be the use of quantum\ncomputers. In this paper, digital quantum simulation is designed for lattice\ngauge theory at nonzero density. The quantum variational algorithm is adopted\nto obtain the ground state at nonzero density. A benchmark test is performed in\nthe lattice Schwinger model.",
        "positive": "Critical Behavior of Dynamically Triangulated Quantum Gravity in Four\n  Dimensions: We performed detailed study of the phase transition region in Four\n  Dimensional Simplicial Quantum Gravity, using the dynamical triangulation\napproach. The phase transition between the Gravity and\n  Antigravity phases turned out to be asymmetrical, so that we observed the\nscaling laws only when the Newton constant approached the critical value from\nperturbative side. The curvature susceptibility diverges with the scaling index\n$-.6$. The physical (i.e. measured with heavy particle propagation) Hausdorff\ndimension of the manifolds, which is\n  2.3 in the Gravity phase and 4.6 in the Antigravity phase, turned out to be 4\nat the critical point, within the measurement accuracy. These facts indicate\nthe existence of the continuum limit in Four\n  Dimensional Euclidean Quantum Gravity."
    },
    {
        "anchor": "Study of the Zc+ channel in lattice QCD: Several charged charmonium-like hadrons called $Z_c$ have been recently\ndiscovered by different experiments. In contrast to conventional hadrons these\ncontain at least two valence quarks and antiquarks ($\\bar{c}c\\bar{d}u$). We\nperform a lattice QCD simulation of the $I^G(J^{PC})=1^+(1^{+-})$ channel\nincluding all relevant two-meson operators under 4.3 GeV: $J/\\psi \\pi$,\n$\\psi_{2S}\\pi$, $\\psi_{1D}\\pi$, $D \\bar{D}^*$, $D^* \\bar{D}^*$, $\\eta_c \\rho$\nas well as additional diquark anti-diquark operators. In our $N_f = 2$\nsimulation with pion mass at 266 MeV we are able to identify all two-meson\nlevels within the energy region of interest. However we find no additional\nlevel identifiable as a candidate for $Z_c$.",
        "positive": "SU(3)-breaking effects in kaon and hyperon semileptonic decays from\n  lattice QCD: We discuss the result of a recent quenched lattice calculation of the K -> pi\nvector form factor at zero-momentum transfer, relevant for the determination of\n|V_us| from K-> pi l nu decays. Using suitable double ratios of three-point\ncorrelation functions, we show that it is possible to calculate this quantity\nat the percent-level precision. The leading quenched effects are corrected for\nby means of quenched chiral perturbation theory. The final result, f+(0) =\n0.960 +- 0.005_stat +- 0.007_syst, turns out to be in good agreement with the\nold quark model estimate made by Leutwyler and Roos. In this paper, we discuss\nthe phenomenological impact of the lattice result for the extraction of |V_us|,\nby updating the analysis of K -> pi l nu decays with the most recent\nexperimental data. We also present a preliminary lattice study of hyperon Sigma\n-> n l nu decays, based on a similar strategy."
    },
    {
        "anchor": "Dimensional reduction and the phase diagram of 5d Yang-Mills theory: We present a non-perturbative study of the phase diagram of 5d SU(2)\nYang-Mills theory with one compact extra dimension on the lattice. Assuming at\nleast a modest scale separation between the cutoff and the compactification\nscales leads to an exponential separation between the compactification scale\nand the four-dimensional correlation length. While we demonstrate that it is\nnot possible to take a full five-dimensional continuum limit, this dynamical\ngeneration of scale hierarchy opens up the possibility for us to make limited,\nbut non-perturbative, predictions about continuum theories whose low-energy\nsector is described by an effective 5d Yang-Mills theory.",
        "positive": "Hyperon sigma terms for 2+1 quark flavours: QCD lattice simulations determine hadron masses as functions of the quark\nmasses. From the gradients of these masses and using the Feynman-Hellmann\ntheorem the hadron sigma terms can then be determined. We use here a novel\napproach of keeping the singlet quark mass constant in our simulations which\nupon using an SU(3) flavour symmetry breaking expansion gives highly\nconstrained (i.e. few parameter) fits for hadron masses in a multiplet. This is\na highly advantageous procedure for determining the hadron mass gradient as it\navoids the use of delicate chiral perturbation theory. We illustrate the\nprocedure here by estimating the light and strange sigma terms for the baryon\noctet."
    },
    {
        "anchor": "Partially-Quenched Nucleon-Nucleon Scattering: Nucleon-nucleon scattering is studied to next-to-leading order in a\npartially-quenched extension of an effective field theory used to describe\nmulti-nucleon systems in QCD. The partially-quenched nucleon-nucleon amplitudes\nwill play an important role in relating lattice simulations of the two-nucleon\nsector to nature.",
        "positive": "Pion Distribution Amplitude from Lattice QCD: We have calculated the second moment of the pion light-cone distribution\namplitude using two flavors of dynamical (clover) fermions on lattices of\ndifferent volumes, lattice spacings between $0.06 \\, \\mathrm {fm}$ and $0.08 \\,\n\\mathrm {fm}$ and pion masses down to $m_\\pi\\sim 150 \\, \\mathrm {MeV}$. Our\nresult for the second Gegenbauer coefficient is $a_2 = 0.1364(154)(145)$ and\nfor the width parameter $\\langle \\xi^2 \\rangle = 0.2361(41)(39)$. Both numbers\nrefer to the scale $\\mu=2 \\, \\mathrm {GeV}$in the $\\overline{\\text{MS}}$\nscheme, the first error is statistical including the uncertainty of the chiral\nextrapolation, and the second error is the estimated uncertainty coming from\nthe nonperturbatively determined renormalization factors."
    },
    {
        "anchor": "Static potential for the quark-antiquark-gluon hybrid system in lattice\n  QCD: The static gluon-quark-antiquark interaction is investigated using lattice\nQCD techniques. A Wilson loop adequate to the static hybrid three-body system\nis developed and, using a $24^3 \\times 48$ periodic lattice with $\\beta = 6.2$,\nthe potential energy of the system is measured for different geometries. For\nthe medium range behaviour, when the quarks are far apart, we find a string\ntension which is compatible with two fundamental strings. On the other hand,\nwhen the quark and antiquark are nearby, the string tension is larger than two\nfundamental strings and is compatible with the Casimir scaling.",
        "positive": "Heavy quarks at finite temperature: New incarnations of heavy-ion collision experiments are turning our attention\nto hard processes and a more fine-grained resolution of the QGP. In this\nendeavor quarkonia or open heavy flavors turn out to be versatile probes, which\nare usually described through models based on perturbative QCD, AdS, and\neffective field theories. The lattice provides nonperturbative input and\nconstraints to such models.\\newline In-medium bottomonia, the complex static\nquark-antiquark potential, and the heavy-quark momentum diffusion coefficient\nare key quantities where lattice gauge theory has recently achieved significant\nprogress with impact for heavy-ion phenomenology. We review these lattice\nresults, relate them to phenomenological applications, and close with an\noutlook."
    },
    {
        "anchor": "The chiral condensate on 2-flavor staggered configurations from an\n  overlap operator: We measure the low lying eigenmodes of an overlap Dirac operator on 2--flavor\nstaggered configurations. By comparing the eigenmode distribution to the\npredictions of Random Matrix Theory we test to what accuracy staggered\nconfigurations describe continuum QCD. The agreement between the numerical data\nand RMT implies that at our quark mass values the lattice artifacts of the\nstaggered configurations are comparable to overlap configurations. We identify\nthe overlap valence mass that best matches the staggered sea quarks and predict\nthe value of the infinite volume 2-flavor chiral condensate.",
        "positive": "Exact chiral invariance at finite density on the lattice: We propose a lattice action for the overlap Dirac matrix with nonzero\nchemical potential which is shown to preserve the chiral invariance on the\nlattice exactly. We further demonstrate it to arise from the Domain wall by\nletting the chemical potential count only the physically relevant wall modes."
    },
    {
        "anchor": "The strange degrees of freedom in QCD at high temperature: We discuss recent results on fluctuations of conserved charges, and their\napproach to the hadron resonance gas at temperatures below the chiral crossover\n(Tc) as well as to a gas of free quarks at very high temperatures. We will\nfocus on the strange degrees of freedom and verify that they are consistent\nwith those of an uncorrelated gas of hadrons for temperatures of T<160 MeV and\nthat they can be described by a quasi particle model at best for T>2Tc. To\nextract this information we use all cumulants of net baryon number and net\nstrangeness fluctuations and their correlations up to the fourth order. In\nparticular we propose observables that serve as indicator for the validity of\nthe hadronic degrees of freedom and show that the partial pressures from\ndifferent strangeness sectors agree separately with HRG model predictions.",
        "positive": "Monte Carlo approach to the string/M-theory: It has long been conjectured that certain supersymmetric Yang-Mills (SYM)\ntheories provide us with nonperturbative formulations of the string/M-theory.\nAlthough the supersymmetry (SUSY) on lattice is notoriously difficult in\ngeneral, for a class of theories important for the string/M-theory various\nlattice and non-lattice methods, which enable us to study them on computers,\nhave been proposed by now. In this talk, firstly I explain how SYM and\nstring/M-theory are related. Then I explain why the lattice SUSY is difficult\nin general, and how the difficulties are solved in theories related to\nstring/M-theory. Then I review the status of the simulations. It is explained\nthat some stringy effects are correctly incorporated in SYM. Furthermore,\nconcrete values can be obtained from the SYM side, even when a direct\ncalculation on the string theory side is impossible by the state-of-the-art\ntechniques. We also comment on other recent developments, including the\nmembrane mini-revolution in 2008 and simulation of the matrix model formulation\nof the string theory."
    },
    {
        "anchor": "TOPOLOGICAL OBJECTS AND CONFINEMENT ON THE LATTICE: First we discuss various topological objects (monopoles, ``minopoles'' and\n``hybrids'') which may be important for the confinement mechanism in various\nabelian projections. The second topic is the string between quark and\nantiquark. The standard quantum string with the Nambu-Goto action exists only\nin D=26. If we start from the field theory, in which the string excitations\nexist, and change the variables in the path integral to the string variables,\nthen the Jacobian appears. This Jacobian generates the correction to the\nNambu-Goto action. For this effective action the conformal anomaly cancels in\nD=4. Thus we get the quantum string theory in D=4.",
        "positive": "Improving QCD with fermions: the 2 dimensional case of QCD with Sea\n  Quarks: We study QCD in 2 dimensions using the improved lattice fermionic Hamiltonian\nproposed by Luo, Chen, Xu and Jiang. The vector mass and the chiral condensate\nare computed for various $SU(N_C)$ gauge groups. We do observe considerable\nimprovement in comparison with the Wilson quark case."
    },
    {
        "anchor": "Ratio of flavour non-singlet and singlet scalar density renormalisation\n  parameters in $N_\\mathrm{f}=3$ QCD with Wilson quarks: We determine non-perturbatively the normalisation factor $r_\\mathrm{m}\\equiv\nZ_{\\rm S}/Z_{\\rm S}^{0}$, where $Z_{\\rm S}$ and $Z_{\\rm S}^{0}$ are the\nrenormalisation parameters of the flavour non-singlet and singlet scalar\ndensities, respectively. This quantity is required in the computation of quark\nmasses with Wilson fermions and for instance the renormalisation of nucleon\nmatrix elements of scalar densities. Our calculation involves simulations of\nfinite-volume lattice QCD with the tree-level Symanzik-improved gauge action,\n$N_\\mathrm{f} = 3$ mass-degenerate $\\mathrm{O}(a)$ improved Wilson fermions and\nSchr\\\"odinger functional boundary conditions. The slope of the current quark\nmass, as a function of the subtracted Wilson quark mass is extracted both in a\nunitary setup (where nearly chiral valence and sea quark masses are degenerate)\nand in a non-unitary setup (where all valence flavours are chiral and the sea\nquark masses are small). These slopes are then combined with $Z \\equiv Z_{\\rm\nP}/(Z_{\\rm S}Z_{\\rm A})$ in order to obtain $r_\\mathrm{m}$. A novel chiral Ward\nidentity is employed for the calculation of the normalisation factor $Z$. Our\nresults cover the range of gauge couplings corresponding to lattice spacings\nbelow $0.1\\,$fm, for which $N_\\mathrm{f} = 2+1$ QCD simulations in large\nvolumes with the same lattice action are typically performed.",
        "positive": "Large-N phase transition in lattice 2-d principal chiral models: We investigate the large-N critical behavior of 2-d lattice chiral models by\nMonte Carlo simulations of U(N) and SU(N) groups at large N. Numerical results\nconfirm strong coupling analyses, i.e. the existence of a large-N second order\nphase transition at a finite $\\beta_c$."
    },
    {
        "anchor": "Elastic Nucleon-Pion scattering amplitudes in the $\u0394$ channel at\n  physical pion mass from Lattice QCD: We present an investigation of pion-nucleon elastic scattering in the\n$I\\,(J^P) = \\frac{3}{2}\\,(\\frac{3}{2}^+)$ channel using lattice QCD with\ndegenerate up and down, strange and charm quarks with masses tuned to their\nphysical values. We use an ensemble of twisted mass fermions with box size $L =\n5.1\\,\\mathrm{fm}$ and lattice spacing $a = 0.08\\,\\mathrm{fm}$ and we consider\nthe $\\pi N$ system in rest and moving frames up to total momentum $\\vec{P}^2 =\n3\\,(2\\pi/L)^2$ = 0.17 GeV$^2$. We take into account the finite volume\nsymmetries and $S$- and $P$-wave mixing, and use the L\\\"uscher formalism to\nsimultaneously constrain the $J = 1/2,\\,\\ell = 0$ and $J = 3/2,\\,\\ell = 1$\nscattering amplitudes. We estimate the $\\Delta$ resonance pole in the $P$-wave\nchannel as well as the $S$-wave isospin-3/2 scattering length.",
        "positive": "Perturbative Renormalization and Mixing of Quark and Glue\n  Energy-Momentum Tensors on the Lattice: We report the renormalization and mixing constants to one-loop order for the\nquark and gluon energy-momentum (EM) tensor operators on the lattice. A unique\naspect of this mixing calculation is the definition of the glue EM tensor\noperator. The glue operator is comprised of gauge-field tensors constructed\nfrom the overlap Dirac operator. The resulting perturbative calculations are\nperformed using methods similar to the Kawai approach using the Wilson action\nfor all QCD vertices and the overlap Dirac operator to define the glue EM\ntensor. Our results are used to connect the lattice QCD results of quark and\nglue momenta and angular momenta to the $\\overline{\\text{MS}}$ scheme at input\nscale $\\mu$"
    },
    {
        "anchor": "L\u00fcscher's finite volume test for two-baryon systems with attractive\n  interactions: For the attractive interaction, the L\\\"uscher's finite volume formula gives\nthe phase shift at negative squared moment $k^2<0$ for the ground state in the\nfinite volume, which corresponds to the analytic continuation of the phase\nshift at $k^2<0$ in the infinite volume. Using this fact, we reexamine\nbehaviors of phase shifts at $k^2 <0$ obtained directly from plateaux of\neffective energy shifts in previous lattice studies for two nucleon systems on\nvarious volumes. We have found that data, based on which existences of the\nbound states are claimed, show singular behaviors of the phase shift at\n$k^2<0$, which seem incompatible with smooth behaviors predicted by the\neffective range expansion. This, together with the fake plateau problem for the\ndetermination of the energy shift, brings a serious doubt on existences of the\n$NN$ bound states claimed in previous lattice studies at pion masses heavier\nthan 300 MeV.",
        "positive": "Reply to \"Comment on `Relation between scattering amplitude and\n  Bethe-Salpeter wave function in quantum field theory\"': We reemphasize the momentum dependence of the coefficients of the derivative\nexpansion as already explained in our paper [1]. We also discuss how the\nmomentum dependence plagues the time-dependent HALQCD method and what is a\nnecessary condition for the method to yield valid results being independent of\nthe choice of the interpolating operators."
    },
    {
        "anchor": "Testing the Yang-Mills vacuum wave functional Ansatz in 3+1 dimensions: We proposed a simple Ansatz for the vacuum wave functional (VWF) of SU(2)\ngauge theory in temporal gauge. In 2+1 dimensions, the Ansatz was shown to be a\nfairly good approximation to the true VWF of the theory. Relative probabilities\nof various test configurations in the vacuum can be computed in numerical\nsimulations of lattice-regulated SU(2) gauge theory by the method proposed long\nago by Greensite and Iwasaki. We report promising (albeit still preliminary)\nresults of testing the proposed VWF in 3+1 dimensions on various sets of\nlattice gauge field configurations.",
        "positive": "Lattice Results for the QCD Phase Transition: We discuss recent results for the phase transition in finite-temperature QCD\nfrom numerical (Monte Carlo) simulations of the lattice-regularized theory.\nEmphasis is given to the case of two degenerate light-quark flavors. The order\nof the transition in this case, which could have cosmological implications, has\nnot yet been established."
    },
    {
        "anchor": "Compactified N=1 supersymmetric Yang-Mills theory on the lattice:\n  Continuity and the disappearance of the deconfinement transition: Fermion boundary conditions play a relevant role in revealing the confinement\nmechanism of N=1 supersymmetric Yang-Mills theory with one compactified\nspace-time dimension. A deconfinement phase transition occurs for a\nsufficiently small compactification radius, equivalent to a high temperature in\nthe thermal theory where antiperiodic fermion boundary conditions are applied.\nPeriodic fermion boundary conditions, on the other hand, are related to the\nWitten index and confinement is expected to persist independently of the length\nof the compactified dimension. We study this aspect with lattice Monte Carlo\nsimulations for different values of the fermion mass parameter that breaks\nsupersymmetry softly. We find a deconfined region that shrinks when the fermion\nmass is lowered. Deconfinement takes place between two confined regions at\nlarge and small compactification radii, that would correspond to low and high\ntemperatures in the thermal theory. At the smallest fermion masses we find no\nindication of a deconfinement transition. These results are a first signal for\nthe predicted continuity in the compactification of supersymmetric Yang-Mills\ntheory.",
        "positive": "Lattice QCD study of partial restoration of chiral symmetry in the\n  flux-tube: Using the overlap-Dirac eigenmodes, we study the spatial distribution of the\nchiral condensate around static color sources in lattice QCD. Between the color\nsources, there appears a color-flux tube, which leads a linear confining\npotential. By measuring a local value of the chiral condensate, we show that\nthe magnitude of the condensate is reduced inside the flux-tube for both\nquark-antiquark and three-quark systems. These results suggest that chiral\nsymmetry is partially restored in the flux-tube. The reduction of the\ncondensate is estimated to be about 20 $\\sim$ 30% at the center of the flux."
    },
    {
        "anchor": "Progress on Perfect Lattice Actions for QCD: We describe a number of aspects in our attempt to construct an approximately\nperfect lattice action for QCD. Free quarks are made optimally local on the\nwhole renormalized trajectory and their couplings are then truncated by\nimposing 3-periodicity. The spectra of these short ranged fermions are\nexcellent approximations to continuum spectra. The same is true for free\ngluons. We evaluate the corresponding perfect quark-gluon vertex function,\nidentifying in particular the ``perfect clover term''. First simulations for\nheavy quarks show that the mass is strongly renormalized, but again the\nrenormalized theory agrees very well with continuum physics. Furthermore we\ndescribe the multigrid formulation for the non-perturbative perfect action and\nwe present the concept of an exactly (quantum) perfect topological charge on\nthe lattice.",
        "positive": "Spontaneous symmetry breaking in a two-doublet lattice Higgs model: An SU(2) lattice gauge theory with two doublets of complex scalar fields is\nconsidered. All continuous symmetries are identified and, using the\nnonperturbative methods of lattice field theory, the phase diagram is mapped\nout by direct numerical simulation. Two-doublet models contain phase\ntransitions that separate qualitatively distinct regions of the parameter\nspace. In some regions global symmetries are spontaneously broken. For some\nspecial choices of the model parameters, the symmetry-breaking order parameter\nis calculated. The pattern of symmetry breaking is verified further through\nobservation of Goldstone bosons."
    },
    {
        "anchor": "Asymptotically free models and discrete non-Abelian groups: We study the two-dimensional renormalization-group flow induced by\nperturbations that reduce the global symmetry of the O(3) sigma-model to the\ndiscrete symmetries of Platonic solids. We estimate the value of the\ncorrelation length at which differences in the behaviour of the various models\nshould be expected. For the icosahedron model, we find xi > 200. We provide an\nexplanation for the recent numerical results of Patrascioiu and Seiler and of\nHasenfratz and Niedermayer.",
        "positive": "Progress report on testing robustness of the Newton method in data\n  analysis on 2-point correlation function using a MILC HISQ ensemble: We report recent progress in data analysis on the two point correlation\nfunctions which will be prerequisite to obtain semileptonic form factors for\nthe $B_{(s)} \\to D_{(s)}\\ell\\nu$ decays. We use a MILC HISQ ensemble for the\nmeasurement. We use the HISQ action for light quarks, and the Oktay-Kronfeld\n(OK) action for the heavy quarks ($b$ and $c$). We used a sequential Bayesian\nmethod for the data analysis. Here we test the new fitting methodology of\nBenjamin J.~Choi in a completely independent manner."
    },
    {
        "anchor": "Gauge/gravity duality and lattice simulations of one dimensional SYM\n  with sixteen supercharges: We study the gauge/gravity duality for supersymmetric SU(N) Yang-Mills theory\nin 1+0 dimension with sixteen supercharges using lattice simulations. The\nconjectured duality states that the gravity side is described by N D0-branes in\ntype IIA superstring at large N, and the thermal gauge theory reproduces the\nblack hole thermodynamics at low temperature. In this paper, we explain the\nSugino lattice action used in the simulations in detail, and examine the\nsupersymmetric Ward-Takahashi identity to confirm the restoration of\nsupersymmetry in the continuum limit. We also estimate the internal energy of\nthe black hole from the lattice results for N=14,32, and find that it smoothly\napproaches the prediction of the gravity side as the temperature decreases.",
        "positive": "Monopoles contra vortices in SU(2) lattice gauge theory?: We show that the scenario of vortex induced confinement of center--projected\nSU(2) lattice gauge theory is not necessarily in conflict with the findings in\nthe positive plaquette model."
    },
    {
        "anchor": "Riemannian manifold hybrid Monte Carlo in lattice QCD: Critical slowing down presents a critical obstacle to lattice QCD calculation\nat the smaller lattice spacings made possible by Exascale computers. Inspired\nby the concept of Fourier acceleration, we study a version of the Riemannian\nManifold HMC (RMHMC) algorithm in which the canonical mass term of the HMC\nalgorithm is replaced by a rational function of the SU(3) gauge covariant\nLaplacian. We have developed a suite of tools using Chebyshev filters based on\nthe SU(3) gauge covariant Laplacian that provides the power spectra of both the\ngauge and fermion forces and determines the spectral dependence of the\nresulting RMHMC evolution of long- and short-distance QCD observables. These\ntools can be used to optimize the RMHMC mass term and to monitor the resulting\nacceleration mode-wise.",
        "positive": "Hadron spectroscopy of twisted mass lattice QCD at beta = 6.0: Simulations that use the clover action in quenched QCD calculations have a\nlower limit to the quark mass that can be reached, because of the fluctuations\ncaused by exceptional configurations. From this low statistics study, we find\nthat the twisted clover action, recently introduced by the ALPHA collaboration,\ncan be used to simulate quenched QCD at quark masses below those attainable by\nsimulations that use the clover action."
    },
    {
        "anchor": "Recent theoretical developments on QCD matter at finite temperature and\n  density: QCD matter at finite temperature and density is a subject that has witnessed\nvery impressive theoretical developments in the recent years. In this review I\nwill discuss some new insights on the microscopic degrees of freedom of the QCD\nmedium near the chiral crossover transition from lattice QCD. Latest high\nprecision lattice data on the fluctuations and correlations between conserved\ncharges like the baryon number, strangeness can help us to understand and\ndistinguish between different models of interacting hadrons. Furthermore, the\nlatest constraints on the location of the critical end-point and the curvature\nof the critical line will be discussed. In the later part of this review I will\ndiscuss about the insights on the thermal nature of the medium created in heavy\nion collision experiments that have come from the theoretical analysis of the\nparticle yields, and to what extent the lattice data on correlations and\nfluctuations of conserved charges can give us any information about the\nfireball at freezeout.",
        "positive": "Asymptotic scaling from strong coupling in 2-d lattice chiral models: Two dimensional $N=\\infty$ lattice chiral models are investigate by a strong\ncoupling analysis. Strong coupling expansion turns out to be predictive for the\nevaluation of continuum physical quantities, to the point of showing asymptotic\nscaling (within 5\\%)."
    },
    {
        "anchor": "Recent algorithm and machine developments for lattice QCD: I review recent machine trends and algorithmic developments for dynamical\nlattice QCD simulations with the HMC algorithm for Wilson-type fermions. The\ntopics include the trend toward multi-core processors and general purpose GPU\n(GPGPU) computing, and improvements on the quark determinant preconditioning,\nmolecular dynamics integrator, and quark solvers. I also discuss the prospect\non the use of these techniques on the forthcoming petaflops machines.",
        "positive": "Quantum Link Models: A Discrete Approach to Gauge Theories: We construct lattice gauge theories in which the elements of the link\nmatrices are represented by non-commuting operators acting in a Hilbert space.\nThese quantum link models are related to ordinary lattice gauge theories in the\nsame way as quantum spin models are related to ordinary classical spin systems.\nHere U(1) and SU(2) quantum link models are constructed explicitly. As\nHamiltonian theories quantum link models are nonrelativistic gauge theories\nwith potential applications in condensed matter physics. When formulated with a\nfifth Euclidean dimension, universality arguments suggest that dimensional\nreduction to four dimensions occurs. Hence, quantum link models are also\nreformulations of ordinary quantum field theories and are applicable to\nparticle physics, for example to QCD. The configuration space of quantum link\nmodels is discrete and hence their numerical treatment should be simpler than\nthat of ordinary lattice gauge theories with a continuous configuration space."
    },
    {
        "anchor": "QCD for Coarse Lattices: This is the Lattice '95 review of recent progress towards accurate QCD\nsimulations using very coarse lattices. This development could have\nrevolutionary implications for low energy (nonperturbative) QCD.",
        "positive": "The nucleon spin and momentum decomposition using lattice QCD\n  simulations: We determine within lattice QCD, the nucleon spin carried by valence and sea\nquarks, and gluons. The calculation is performed using an ensemble of gauge\nconfigurations with two degenerate light quarks with mass fixed to\napproximately reproduce the physical pion mass. We find that the total angular\nmomentum carried by the quarks in the nucleon is $J_{u+d+s}{=}0.408(61)_{\\rm\nstat.}(48)_{\\rm syst.}$ and the gluon contribution is $J_g {=}0.133(11)_{\\rm\nstat.}(14)_{\\rm syst.}$ giving a total of $J_N{=}0.54(6)_{\\rm stat.}(5)_{\\rm\nsyst.}$ consistent with the spin sum. For the quark intrinsic spin contribution\nwe obtain $\\frac{1}{2}\\Delta \\Sigma_{u+d+s}{=}0.201(17)_{\\rm stat.}(5)_{\\rm\nsyst.}$. All quantities are given in the $\\overline{\\textrm{MS}}$ scheme at\n2~GeV. The quark and gluon momentum fractions are also computed and add up to\n$\\langle x\\rangle_{u+d+s}+\\langle x\\rangle_g{=}0.804(121)_{\\rm stat.}(95)_{\\rm\nsyst.}+0.267(12)_{\\rm stat.}(10)_{\\rm syst.}{=}1.07(12)_{\\rm stat.}(10)_{\\rm\nsyst.}$ satisfying the momentum sum."
    },
    {
        "anchor": "Scaling and Density of Lee-Yang Zeroes in the Four Dimensional Ising\n  Model: The scaling behaviour of the edge of the Lee--Yang zeroes in the four\ndimensional Ising model is analyzed. This model is believed to belong to the\nsame universality class as the $\\phi^4_4$ model which plays a central role in\nrelativistic quantum field theory. While in the thermodynamic limit the scaling\nof the Yang--Lee edge is not modified by multiplicative logarithmic\ncorrections, such corrections are manifest in the corresponding finite--size\nformulae. The asymptotic form for the density of zeroes which recovers the\nscaling behaviour of the susceptibility and the specific heat in the\nthermodynamic limit is found to exhibit logarithmic corrections too. The\ndensity of zeroes for a finite--size system is examined both analytically and\nnumerically.",
        "positive": "A scalable PC-based parallel computer for lattice QCD: A PC-based parallel computer for medium/large scale lattice QCD simulations\nis suggested. The Eotvos Univ., Inst. Theor. Phys. cluster consists of 137\nIntel P4-1.7GHz nodes. Gigabit Ethernet cards are used for nearest neighbor\ncommunication in a two-dimensional mesh. The sustained performance for\ndynamical staggered(wilson) quarks on large lattices is around 70(110) GFlops.\nThe exceptional price/performance ratio is below $1/Mflop."
    },
    {
        "anchor": "Amplitude ratios for the mass spectrum of the 2d Ising model in the\n  high-T, H \\neq 0 phase: We study the behaviour of the 2d Ising model in the symmetric high\ntemperature phase in presence of a small magnetic perturbation. We successfully\ncompare the quantum field theory predictions for the shift in the mass spectrum\nof the theory with a set of high precision transfer matrix results. Our results\nrule out a prediction for the same quantity obtained some years ago with strong\ncoupling methods.",
        "positive": "Form Factors for Semileptonic Decays of Heavy-Light Hadrons: The strong coupling lattice QCD solution \\cite{APtifr} for the Isgur-Wise\nfunctions, parametrising the semileptonic decay form factors of hadrons\ncontaining a single heavy quark, is reviewed. Several useful features connected\nwith the result are pointed out."
    },
    {
        "anchor": "Phase diagram of the two-dimensional O(3) model from dual lattice\n  simulations: We have simulated the asymptotically free two-dimensional O(3) model at\nnonzero chemical potential using the model's dual representation. We first\ndemonstrate how the latter solves the sign (complex action) problem. The system\ndisplays a crossover at nonzero temperature, while at zero temperature it\nundergoes a quantum phase transition when mu reaches the particle mass\n(generated dynamically similar to QCD). The density follows a square root\nbehavior universal for repulsive bosons in one spatial dimension. We have also\nmeasured the spin stiffness, known to be sensitive to the spatial correlation\nlength, using different scaling trajectories to zero temperature and infinite\nsize. It points to a dynamical critical exponent z=2. Comparisons to\nthermodynamic Bethe ansaetze are shown as well.",
        "positive": "Towards High-Precision Parton Distributions From Lattice QCD via\n  Distillation: We apply the Distillation spatial smearing program to the extraction of the\nunpolarized isovector valence PDF of the nucleon. The improved volume sampling\nand control of excited-states afforded by distillation leads to a dramatically\nimproved determination of the requisite Ioffe-time Pseudo-distribution (pITD).\nThe impact of higher-twist effects is subsequently explored by extending the\nWilson line length present in our non-local operators to one half the spatial\nextent of the lattice ensemble considered. The valence PDF is extracted by\nanalyzing both the matched Ioffe-time Distribution (ITD), as well as a direct\nmatching of the pITD to the PDF. Through development of a novel prescription to\nobtain the PDF from the pITD, we establish a concerning deviation of the pITD\nfrom the expected DGLAP evolution of the pseudo-PDF. The presence of DGLAP\nevolution is observed once more following introduction of a discretization term\ninto the PDF extractions. Observance and correction of this discrepancy further\nhighlights the utility of distillation in such structure studies."
    },
    {
        "anchor": "A new approach for Delta form factors: We discuss a new approach to reducing excited state contributions from two-\nand three-point correlation functions in lattice simulations. For the purposes\nof this talk, we focus on the Delta(1232) resonance and discuss how this new\nmethod reduces excited state contamination from two-point functions and mention\nhow this will be applied to three-point functions to extract hadronic form\nfactors.",
        "positive": "Testing the Witten-Veneziano mechanism with the Yang-Mills gradient flow\n  on the lattice: We present a precise computation of the topological charge distribution in\nthe $SU(3)$ Yang-Mills theory. It is carried out on the lattice with high\nstatistics Monte Carlo simulations by employing the clover discretization of\nthe field strength tensor combined with the Yang-Mills gradient flow. The flow\nequations are integrated numerically by a fourth-order structure-preserving\nRunge-Kutta method. We have performed simulations at four lattice spacings and\nseveral lattice sizes to remove with confidence the systematic errors in the\nsecond (topological susceptibility $\\chi_t^\\text{YM}$) and the fourth cumulant\nof the distribution. In the continuum we obtain the preliminary results\n$t_0^2\\chi_t^\\text{YM}=6.53(8)\\times 10^{-4}$ and the ratio between the fourth\nand the second cumulant $R=0.233(45)$. Our results disfavour the\n$\\theta$-behaviour of the vacuum energy predicted by dilute instanton models,\nwhile they are compatible with the expectation from the large-$N_c$ expansion."
    },
    {
        "anchor": "Exploring Composite Dark Matter with an SU(4) gauge theory with 1\n  fermion flavor: Several SU(N) gauge theories have been explored as candidates for producing\nstable dark matter particles that can explain their relative abundance, while\nalso evading current constraints from direct, indirect and collider searches.\nIn this talk, I will present the confinement and spectral properties of a new\nmodel we name \"Hyper Stealth Dark Matter\", which involves an SU(4) gauge theory\nwith 1 quark flavor. The lightest baryon in this theory can be a potential dark\nmatter candidate as it is protected from decay and hence can evade detection\nwith a mass of just a few GeV. Existence of a first order confinement\ntransition would open the possibility of potential detection of gravitational\nwaves from such a transition at future observatories.",
        "positive": "Is there a $\u03c1$ in the O(4) $\u03bb\u03c6^4_4$ theory?: A Monte Carlo simulation of the O(4) $\\lambda \\phi^4$ theory in the broken\nphase is performed on a hypercubic lattice in search of an I=1, J=1 resonance.\nThe region of the cutoff theory where the interaction is strong is investigated\nsince it is there that a resonance would be expected to have a better chance to\nform. In that region the presence of an I=1, J=1 resonance with mass below the\ncutoff is excluded."
    },
    {
        "anchor": "Lattice-QCD Calculations of TMD Soft Function Through Large-Momentum\n  Effective Theory: The transverse-momentum-dependent (TMD) soft function is a key ingredient in\nQCD factorization of Drell-Yan and other processes with relatively small\ntransverse momentum. We present a lattice QCD study of this function at\nmoderately large rapidity on a 2+1 flavor CLS dynamic ensemble with $a=0.098$\nfm. We extract the rapidity-independent (or intrinsic) part of the soft\nfunction through a large-momentum-transfer pseudo-scalar meson form factor and\nits quasi-TMD wave function using leading-order factorization in large-momentum\neffective theory. We also investigate the rapidity-dependent part of the soft\nfunction---the Collins-Soper evolution kernel---based on the large-momentum\nevolution of the quasi-TMD wave function.",
        "positive": "Chemical potential response of pseudoscalar meson masses in the\n  Nambu--Jona-Lasinio model: Using the Nambu--Jona-Lasinio (NJL) model we study chemical potential\nresponse of the pion and kaon masses as a function of temperature and chemical\npotential, i.e., dm/d\\mu (T, \\mu). First, we obtain the responses assuming the\nvector-axial vector coupling is zero (g_V=0). Then, we include a non-zero g_V\nand study the effects of g_V on the responses. We find that the behavior of\ndm/d\\mu for the pion is quite different from that for the kaon. It means that\ndm/d\\mu is much dependent on the mass difference between the two quarks, i.e.,\nthe u and s quarks (or even between the u and d quarks). Our results may give a\nclue to future studies of dm/d\\mu on the lattice."
    },
    {
        "anchor": "Dualization of non-abelian lattice gauge theory with Abelian Color\n  Cycles (ACC): We discuss a new approach to strong coupling expansion and dual\nrepresentations for non-abelian lattice gauge theories. The Wilson gauge action\nis decomposed into a sum over \"abelian color cycles\" (ACC), which are loops\naround plaquettes visiting different colors at the corners. ACCs are complex\nnumbers and thus commute such that a dual representation of a non-abelian\ntheory can be obtained as in the abelian case. We apply the ACC approach to\nSU(2) and SU(3) lattice gauge theory and exactly rewrite the two partition sums\nin a strong coupling series where all gauge integrals are known in closed form.",
        "positive": "Gauge fixing in lattice QCD with multi-GPUs: Here we present the cuLGT code for gauge fixing in lattice gauge field\ntheories with graphic processing units (GPUs). Implementations for SU(3)\nCoulomb, Landau and maximally Abelian gauge fixing are available and the\noverrelaxation, stochastic relaxation and simulated annealing algorithms are\nsupported. Performance results for single and multi-GPUs are given."
    },
    {
        "anchor": "How to Measure the Fractal Geometry of the Relativistic Fermion\n  Propagator: We study the geometry of propagation of relativistic fermions. We propose how\nto measure its quantum mechanical length. Numerical lattice results for the\nfree propagator of Dirac-Wilson fermions yield Hausdorff dimension d_H=2 for\nthe unit-matrix component and d_H=1 for any gamma-matrix component. A possible\ngeneralization when matter interacts with radiation is discussed.",
        "positive": "Chiral perturbation theory and nucleon-pion-state contaminations in\n  lattice QCD: Multi-particle states with additional pions are expected to be a\nnon-negligible source of excited-state contamination in lattice simulations at\nthe physical point. It is shown that baryon chiral perturbation theory can be\nemployed to calculate the contamination due to two-particle nucleon-pion states\nin various nucleon observables. Leading order results are presented for the\nnucleon axial, tensor and scalar charge and three Mellin moments of parton\ndistribution functions (quark momentum fraction, helicity and transversity\nmoment). Taking into account phenomenological results for the charges and\nmoments the impact of the nucleon-pion-states on lattice estimates for these\nobservables can be estimated. The nucleon-pion-state contribution results in an\noverestimation of all charges and moments obtained with the plateau method. The\noverestimation is at the 5-10% level for source-sink separations of about 2 fm.\nThe source-sink separations accessible in contemporary lattice simulations are\nfound to be too small for chiral perturbation theory to be directly applicable."
    },
    {
        "anchor": "Dual Polyakov loop model at finite density: phase diagram and screening\n  masses: We consider a dual representation of an effective three-dimensional Polyakov\nloop model for the SU(3) theory at nonzero real chemical potential. This\nrepresentation is free of the sign problem and can be used for numeric\nMonte-Carlo simulations. These simulations allow us to locate the line of\nsecond order phase transitions, that separates the region of first order phase\ntransition from the crossover one. The behavior of local observables in\ndifferent phases of the model is studied numerically and compared with\npredictions of the mean-field analysis. Our dual formulation allows us to study\nalso Polyakov loop correlation functions. From these results, we extract the\nscreening masses and compare them with large-N predictions.",
        "positive": "MG-MLMC++ as a Variance Reduction Method for Estimating the Trace of a\n  Matrix Inverse: Hutchinson's method estimates the trace of a matrix function $f(D)$\nstochastically using samples $\\tau^Hf(D)\\tau$, where the components of the\nrandom vectors $\\tau$ obey an isotropic probability distribution. Estimating\nthe trace of the inverse of a discretized Dirac operator or variants thereof\nhave become a major challenge in lattice QCD simulations, as they represent the\ndisconnected contribution to certain observables. The Hutchinson Monte Carlo\nsampling, however, suffers from the fact that its accuracy depends\nquadratically on the sample size, making higher precision estimation very\nexpensive. Meyer, Musco, Musco and Woodruff recently proposed an enhancement of\nHutchinson's method, termed \\texttt{Hutch++}, in which the sample space is\nenriched by several vectors of the form $f(D)\\zeta$, $\\zeta$ a random vector as\nin Hutchinson's method. Theoretical analyses show that under certain\ncircumstances the number of these added sample vectors can be chosen in a way\nto reduce the dependence of the variance of the resulting estimator from the\nnumber $N$ of samples from $\\mathcal{O}(1/N)$ to $\\mathcal{O}(1/N^2)$.\n  In this study we combine \\texttt{Hutch++} with our recently suggested\nmultigrid multilevel Monte Carlo approach. We present results for the Schwinger\ndiscretization of the $2$-di\\-men\\-si\\-onal Dirac operator, revealing that the\ntwo approaches contribute additively to variance reduction."
    },
    {
        "anchor": "Scaling behavior at the tricritical point in the fermion-gauge-scalar\n  model: We investigate a strongly coupled U(1) gauge theory with fermions and scalars\non the lattice and analyze whether the continuum limit might be a\nrenormalizable theory with dynamical mass generation. Most attention is paid to\nthe phase with broken chiral symmetry in the vicinity of the tricritical point\nfound in the model. There we investigate the scaling of the masses of the\ncomposite fermion and of some bosonic bound states. As a by-product we confirm\nthe mean-field exponents at the endpoint in the U(1)-Higgs model, by analyzing\nthe scaling of the Fisher zeros.",
        "positive": "Interquark potential, susceptibilities and particle density of two color\n  QCD at finite chemical potential and temperature: We explore the phase diagram of SU(2) Lattice Gauge Theory with dynamical\nfermions in the temperature, mass, chemical potential space. We observe\nqualitative changes of the dependence of the particle density on $\\mu$ and $T$,\nwhich is compatible with that expected of a gas of free massless quarks $n\n\\propto \\mu^3$ only for $T \\simeq T_c$. At the onset for thermodynamics the\ninterquark potential flattens at large separations, indicating enhanced fermion\nscreening and the transition to a deconfined phase. Temporal and spatial\nPolyakov loops behave in different ways, the latter being nearly insensitive to\nthe chemical potential. The rotation of the chiral condensate to a baryonic\ncondensate, as inferred from the susceptibilities, might occur together with a\nreduction of its magnitude in the chiral limit, possibly leading to a critical\ntemperature for diquark condensation smaller than the deconfinement\ntemperature. We further asses the r\\^ole of the chemical potential into the\ngauge dynamics by carrying out a partial quenched calculation. We speculate on\nthe relevance, or lack thereof, of our findings to real QCD."
    },
    {
        "anchor": "Dirac operator as a random matrix and the quenched limit of QCD with\n  chemical potential: The behavior of quenched QCD at nonzero chemical potential $\\mu$ has been a\nlong-standing puzzle. An explicit solution is found using the random matrix\napproach to chiral symmetry breaking. At nonzero $\\mu$ the quenched QCD is not\na simple $n\\to0$ limit of a theory with $n$ quarks: a naive `replica trick'\nfails. A limit that leads to the quenched QCD is that of a theory with $2n$\nquarks: $n$ quarks with original action and $n$ quarks with conjugate action.",
        "positive": "Lattice simulation with the Majorana positivity: While the sign problem of the Dirac fermion is conditioned by the\nsemi-positivity of a determinant, that of the Majorana fermion is conditioned\nby the semi-positivity of a Pfaffian. We introduce one sufficient condition for\nthe semi-positivity of a Pfaffian. Based on the semi-positivity condition, we\nstudy an effective model of the Majorana fermion. We also present the\napplication to the Dirac fermion"
    },
    {
        "anchor": "The strange contribution to $a_\u03bc$ with physical quark masses using\n  M\u00f6bius domain wall fermions: We present preliminary results for the strange leading-order hadronic\ncontribution to the anomalous magnetic moment of the muon using RBC/UKQCD\nphysical point domain wall fermions ensembles. We discuss various analysis\nstrategies in order to constrain the systematic uncertainty in the final\nresult.",
        "positive": "Discussion of the loop formula for the fermionic determinant: A formula expressing the fermionic determinant (a large order polynomial) as\nan infinite product of smaller determinants is derived and discussed. These\nsmaller determinants are of a fixed size, independent of the size of the\nlattice and are indexed by loops of increasing length."
    },
    {
        "anchor": "$I=1$ $\u03c0$-$\u03c0$ scattering at the physical point: We present a preliminary analysis of $I=1$ $\\pi\\,\\pi$ scattering at the\nphysical point. We make use of the stochastic variant of the distillation\nframework (also known as sLapH) to compute the relevant two-point correlation\nmatrices using a basis of single and multihadron interpolating operators to\nestimate the low energy spectra. We perform the L\\\"uscher analysis to determine\nthe scattering phase shift which is finding good agreement with the\nexperimentally obtained phase shifts.",
        "positive": "Failure of the Regge approach in two dimensional quantum gravity: Regge's method for regularizing euclidean quantum gravity is applied to two\ndimensional gravity. We use two different strategies to simulate the Regge path\nintegral at a fixed value of the total area: A standard Metropolis simulation\ncombined with a histogramming method and a direct simulation using a Hybrid\nMonte Carlo algorithm. Using topologies with genus zero and two and a scale\ninvariant integration measure, we show that the Regge method does not reproduce\nthe value of the string susceptibility of the continuum model. We show that the\nstring susceptibility depends strongly on the choice of the measure in the path\nintegral. We argue that the failure of the Regge approach is due to spurious\ncontributions of reparametrization degrees of freedom to the path integral."
    },
    {
        "anchor": "$B$-meson semileptonic form factors on (2+1+1)-flavor HISQ ensembles: We report updates to an ongoing lattice-QCD calculation of the form factors\nfor the semileptonic decays $B \\to \\pi \\ell \\nu$, $B_s \\to K \\ell \\nu$, $B \\to\n\\pi \\ell^+ \\ell^-$, and $B \\to K \\ell^+ \\ell^-$. The tree-level decays $B_{(s)}\n\\to \\pi (K) \\ell \\nu$ enable precise determinations of the CKM matrix element\n$|V_{ub}|$, while the flavor-changing neutral-current interactions $B \\to \\pi\n(K) \\ell^+ \\ell^-$ are sensitive to contributions from new physics. This work\nuses MILC's (2+1+1)-flavor HISQ ensembles at approximate lattice spacings\nbetween $0.057$ and $0.15$ fm, with physical sea-quark masses on four out of\nthe seven ensembles. The valence sector is comprised of a clover $b$ quark (in\nthe Fermilab interpretation) and HISQ light and $s$ quarks. We present\npreliminary results for the form factors $f_0$, $f_+$, and $f_T$, including\nstudies of systematic errors.",
        "positive": "Strong-Coupling Lattice QCD on Anisotropic Lattices: Anisotropic lattice spacings are mandatory to reach the high temperatures\nwhere chiral symmetry is restored in the strong coupling limit of lattice QCD.\nHere, we propose a simple criterion for the nonperturbative renormalisation of\nthe anisotropy coupling in strongly-coupled SU($N$) or U($N$) lattice QCD with\nmassless staggered fermions. We then compute the renormalised anisotropy, and\nthe strong-coupling analogue of Karsch's coefficients (the running anisotropy),\nfor $N=3$. We achieve high precision by combining diagrammatic Monte Carlo and\nmulti-histogram reweighting techniques. We observe that the mean field\nprediction in the continuous time limit captures the nonperturbative scaling,\nbut receives a large, previously neglected correction on the unit prefactor.\nUsing our nonperturbative prescription in place of the mean field result, we\nobserve large corrections of the same magnitude to the continuous time limit of\nthe static baryon mass, and of the location of the phase boundary associated\nwith chiral symmetry restoration. In particular, the phase boundary, evaluated\non different finite lattices, has a dramatically smaller dependence on the\nlattice time extent. We also estimate, as a byproduct, the pion decay constant\nand the chiral condensate of massless SU(3) QCD in the strong coupling limit at\nzero temperature."
    },
    {
        "anchor": "Gauge-invariant quark-antiquark nonlocal condensates in lattice QCD: We study, by numerical simulations on a lattice, the behaviour of the\ngauge-invariant quark-antiquark nonlocal condensates in the QCD vacuum with\ndynamical fermions. A determination is also done in the quenched approximation\nand the results are compared with the full-QCD case. The fermionic correlation\nlength is extracted and compared with the analogous gluonic quantity.",
        "positive": "A novel computational paradigm for a precise determination of the\n  hadronic contribution to $(g_\u03bc-2)$ from lattice QCD: The hadronic contribution to the muon anomalous magnetic moment\n$a_\\mu=(g_\\mu-2)/2$ has to be determined at the per-mille level for the\nStandard Model prediction to match the expected final uncertainty of the\nongoing E989 experiment. That is 3 times better than the current precision from\nthe dispersive approach, and 5-15 times smaller than the uncertainty based on\nthe purely theoretical determinations from lattice QCD. So far the\nstumbling-block is the large statistical error in the Monte Carlo evaluation of\nthe required correlation functions which can hardly be tamed by brute force. In\nthis talk we present our proposal to solve this problem by multi-level Monte\nCarlo integration, a technique which reduces the variance of correlators\nexponentially in the distance of the fields. We report the results of our\nfeasibility tests for the computation of the Hadronic Vacuum Polarization on a\nlattice with a linear extension of 3~fm, a spacing of 0.065 fm, and a pion mass\nof 270 MeV. Indeed the two-level integration makes the contribution to the\nstatistical error from long-distances de-facto negligible by accelerating its\ninverse scaling with the cost of the simulation. These findings establish\nmulti-level Monte Carlo as a solid and efficient method for a precise lattice\ndetermination of the hadronic contribution to $a_\\mu$."
    },
    {
        "anchor": "QED Corrections to Hadronic Observables: When aiming at the percent precision in hadronic quantities calculated by\nmeans of lattice simulations, isospin breaking effects become relevant. These\nare of two kinds: up/down mass splitting and electromagnetic corrections. In\norder to account properly for the latter, a consistent formulation of\nelectrically-charged states in finite volume is needed. In fact on a periodic\ntorus Gauss law and large gauge transformations forbid the propagation of\nelectrically-charged states. In this talk I will review methods that have been\nused or proposed so far in order to circumvent this problem, while highlighting\npractical as well as conceptual pros and cons. I will also review and discuss\nvarious methods to calculate electromagnetic corrections to hadron masses and\ndecay rates in numerical simulations.",
        "positive": "Quantum ideal hydrodynamics on the lattice: After discussing the problem of defining the hydrodynamic limit from\nmicroscopic scales, we give an introduction to ideal hydrodynamics in the\nLagrange picture, and show that it can be viewed as a field theory, which can\nbe quantized using the usual Feynman sum-over-paths prescription. We then argue\nthat this picture can be connected to the usually neglected thermal microscopic\nscale in the hydrodynamic expansion. After showing that this expansion is\ngenerally non-perturbative, we show how the lattice can be used to understand\nthe impact quantum and thermal fluctuations can have on the fluid behavior."
    },
    {
        "anchor": "Scaling dimension of $4\u03c0$-flux monopole operator in four-flavor\n  three-dimensional QED using lattice simulation: We numerically address the issue of which monopole operators are relevant\nunder renormalization group flow in three-dimensional parity-invariant\nnoncompact QED with $4$ flavors of massless two-component Dirac fermion. Using\nlattice simulation and finite-size scaling analysis of the free energy to\nintroduce monopole-antimonopole pairs in $N=4$ and $N=12$ flavor noncompact\nQED$_3$, we estimate the infrared scaling dimensions of monopole operators that\nintroduce $2\\pi$ and $4\\pi$ fluxes around them. We first show that the\nestimates for the monopole scaling dimensions are consistent with the large-$N$\nexpectations for $N=12$ QED$_3$. Applying the same procedure in $N=4$ QED$_3$,\nwe estimate the scaling dimension of $4\\pi$ flux monopole operator to be\n$3.7(3)$, which allows the possibility of the operator being irrelevant. This\nfinding offers support to the scenario in which higher-flux monopoles are\nirrelevant deformations to the Dirac spin liquid phase that could be realized\non certain non-bipartite lattices by forbidding $2\\pi$-flux monopoles.",
        "positive": "Axial, Scalar and Tensor Charges of the Nucleon from 2+1+1-flavor\n  Lattice QCD: We present results for the isovector axial, scalar and tensor charges\n$g^{u-d}_A$, $g^{u-d}_S$ and $g^{u-d}_T$ of the nucleon needed to probe the\nStandard Model and novel physics. The axial charge is a fundamental parameter\ndescribing the weak interactions of nucleons. The scalar and tensor charges\nprobe novel interactions at the TeV scale in neutron and nuclear\n$\\beta$-decays, and the flavor-diagonal tensor charges $g^{u}_T$, $g^{d}_T$ and\n$g^{s}_T$ are needed to quantify the contribution of the quark electric dipole\nmoment (EDM) to the neutron EDM. The 9 ensembles, generated by the MILC\nCollaboration using the HISQ action with 2+1+1 dynamical flavors, span three\nlattice spacings $a \\approx 0.06, 0.09$ and 0.12 fm and light-quark masses\ncorresponding to the pion masses $M_\\pi \\approx 135, 225$ and 315 MeV.\nHigh-statistics estimates on five ensembles using the all-mode-averaging method\nallow us to quantify all systematic uncertainties and perform a simultaneous\nextrapolation in the lattice spacing, lattice volume and light-quark masses for\nthe connected contributions. Our final estimates, in the $\\overline{\\text{MS}}$\nscheme at 2 GeV, of the isovector charges are $g_A^{u-d} = 1.195(33)(20)$,\n$g_S^{u-d} = 0.97(12)(6) $ and $g_T^{u-d} = 0.987(51)(20)$. The first error\nincludes statistical and all systematic uncertainties except that due to the\nextrapolation Ansatz, which is given by the second error estimate. Combining\nour estimate for $g_S^{u-d}$ with the difference of light quarks masses\n$(m_d-m_u)^{\\rm QCD}=2.67(35)$ MeV given by FLAG, we obtain $(M_N-M_P)^{\\rm\nQCD} = 2.59(49)$ MeV. Estimates of the connected part of the flavor-diagonal\ntensor charges of the proton are $g^{u}_T=0.792(42)$ and $g^{d}_T=-0.194(14)$.\nCombining our new estimates with precision low-energy experiments, we update\nconstraints on novel scalar and tensor interactions, $\\epsilon_{S,T}$, at the\nTeV scale."
    },
    {
        "anchor": "Nonperturbative renormalization of the Delta-S=1 weak Hamiltonian\n  including the G_1 operator: Under renormalization, physical operators can mix with operators which vanish\nby the equations of motion. Such operators cannot contribute to matrix elements\nbetween physical states, but they contribute to operator mixing in\nrenormalization schemes which are defined at an off-shell momentum point, such\nas the popular regularization-invariant schemes. For the first time, we\nrenormalize the lattice $\\Delta S=1$ effective weak Hamiltonian taking into\naccount the most important such operator, $G_1 \\propto \\overline s \\gamma_\\nu\n(1-\\gamma_5) D_\\mu G_{\\mu\\nu} d$. This removes an important systematic error in\ncalculations of weak matrix elements on the lattice.",
        "positive": "Sp(4) gauge theory on the lattice: towards SU(4)/Sp(4) composite Higgs\n  (and beyond): The Sp(4) gauge theory with two Dirac fundamental flavours provides a\ncandidate for the microscopic origin of composite-Higgs models based on the\nSU(4)/Sp(4) coset. We employ a combination of two different, complementary\nstrategies for the numerical lattice calculations, based on the Hybrid Monte\nCarlo and on the Heat Bath algorithms. We perform pure Yang-Mills, quenched\ncomputations and exploratory studies with dynamical Wilson fermions. We present\nthe first results in the literature for the spectrum of glueballs of the pure\nSp(4) Yang-Mills theory, an EFT framework for the interpretation of the masses\nand decay constants of the lightest pion, vector and axial-vector mesons, and a\npreliminary calculation of the latter in the quenched approximation. We show\nthe first numerical evidence of a bulk phase transition in the lattice theory\nwith dynamical Wilson fermions, and perform the technical steps necessary to\nset up future investigations of the mesonic spectrum of the full theory."
    },
    {
        "anchor": "Topological order and the vacuum of Yang-Mills theories: We study, for $SU(2)$ Yang-Mills theories discretized on a lattice, a\nnon-local topological order parameter, the center flux ${{z}}$. We show that:\ni) well defined topological sectors classified by $\\pi_1(SO(3))=\\mathbb{Z}_2$\ncan only exist in the ordered phase of ${{z}}$; ii) depending on the dimension\n$2 \\leq d\\leq 4$ and action chosen, the center flux exhibits a critical\nbehaviour sharing striking features with the Kosterlitz-Thouless type of\ntransitions, although belonging to a novel universality class; iii) such\ncritical behaviour does not depend on the temperature $T$. Yang-Mills theories\ncan thus exist in two different continuum phases, characterized by an either\ntopologically ordered or disordered vacuum; this reminds of a quantum phase\ntransition, albeit controlled by the choice of symmetries and not by a physical\nparameter.",
        "positive": "Revisiting the deconfinement phase transition in SU(4) Yang-Mills theory\n  in 2+1 dimensions: In order to deepen our understanding of the nature of the deconfinement phase\ntransition for various gauge groups, we investigate SU(4) Yang-Mills theory in\n2+1 dimensions. We find that the transition is weakly first order. We perform\nextensive Monte Carlo simulations on lattices with temporal extent N_t = 3, 4\nand 5, and spatial sizes up to N_s = 20 N_t. We observe coexistence of confined\nand deconfined phases at the critical temperature, and finite-size scaling\nshows consistency with first order exponents. The continuum extrapolation of\nthe latent heat yields L_h/T_c^3=0.188(17)."
    },
    {
        "anchor": "Instanton dominance of topological charge fluctuations in QCD?: We consider the local chirality of near-zero eigenvectors from Wilson-Dirac\nand clover improved Wilson-Dirac lattice operators as proposed recently by\nHorv\\'ath et al. We studied finer lattices and repaired for the loss of\northogonality due to the non-normality of the Wilson-Dirac matrix. As a result\nwe do see a clear double peak structure on lattices with resolutions higher\nthan 0.1 fm. We found that the lattice artifacts can be considerably reduced by\nexploiting the biorthogonal system of left and right eigenvectors. We conclude\nthat the dominance of instantons on topological charge fluctuations is not\nruled out by local chirality measurements.",
        "positive": "First-order bulk transitions in large-$N$ lattice Yang--Mills theories\n  using the density of states: We use the Logarithmic Linear Relaxation (LLR) density of states algorithm to\nstudy the bulk phase transitions of pure-gauge SU($N$) lattice Yang--Mills\ntheories with $4 \\leq N \\leq 8$. This approach avoids super-critical slowing\ndown at such transitions, which poses a problem for traditional importance\nsampling Monte-Carlo methods. We analyse the effect of different updating\nstrategies within the LLR algorithm, different reconstruction techniques of the\ndensity of states and different lattice volumes. By comparing our results for\nthe weakly first-order SU(5) bulk phase transition against those for the\nstronger transitions with $N \\geq 6$, we demonstrate the advantages of the LLR\nmethod for analyses of strong transitions with large latent heat."
    },
    {
        "anchor": "Thermodynamics of two-flavor lattice QCD with an improved Wilson quark\n  action at non-zero temperature and density: We report the current status of our systematic studies of the QCD\nthermodynamics by lattice QCD simulations with two flavors of improved Wilson\nquarks. We evaluate the critical temperature of two flavor QCD in the chiral\nlimit at zero chemical potential and show the preliminary result. Also we\ndiscuss fluctuations at none-zero temperature and density by calculating the\nquark number and isospin susceptibilities and their derivatives with respect to\nchemical potential.",
        "positive": "Higher order quantization conditions for two spinless particles: Lattice QCD calculations of scattering phaseshifts and resonance parameters\nin the two-body sector are becoming precision studies. Early calculations\nemployed L\\\"uscher's formula for extracting these quantities at lowest order.\nAs the calculations become more ambitious, higher-order relations are required.\nIn this study we derive higher-order quantization conditions and introduce a\nmethod to transparently cross-check our results. This is an important step\ngiven the involved derivations of these formulae. We derive quantization\nconditions up to $\\ell=5$ partial waves in both cubic and elongated geometries,\nand for states with zero and non-zero total momentum. All 45 quantization\nconditions we include here (22 in cubic box, 23 in elongated box) pass our\ncross-check test."
    },
    {
        "anchor": "Position-Space Renormalisation of the Energy-Momentum Tensor: There is increasing interest in the study of nonperturbative aspects of\nthree-dimensional quantum field theories (QFT). They appear as holographic dual\nto theories of (strongly coupled) gravity. For instance, in Holographic\nCosmology, the two-point function of the Energy-Momentum Tensor (EMT) of a\nparticular class of three-dimensional QFTs can be mapped into the power\nspectrum of the Cosmic Microwave Background in the gravitational theory.\nHowever, the presence of divergent contact terms poses challenges in extracting\na renormalised EMT two-point function on the lattice. Using a $\\phi^4$ theory\nof adjoint scalars valued in the $\\mathfrak{su}(N)$ Lie Algebra as a\nproof-of-concept motivated by Holographic Cosmology, we apply a novel method\nfor filtering out such contact terms by making use of infinitely differentiable\n\"bump\" functions which enforce a smooth window that excludes contributions at\nzero spatial separation. The process effectively removes the local contact\nterms and allows us to extract the continuum limit behaviour of the\nrenormalised EMT two-point function.",
        "positive": "Stochastic Perturbation Theory and the Gluon Condensate: On the lattice searching for the gluon condensate is difficult because a\nlarge perturbative contribution to the expectation value of the action has to\nbe subtracted before looking for a small contribution from a possible gluon\ncondensate. The perturbative calculation therefore has to be very precise. We\nuse a modified version of stochastic perturbation theory to calculate a\nperturbative series in a boosted coupling, which converges more rapidly than\nthe series with the usual lattice coupling, reducing the uncertainties in our\nresults. We do not see any condensate of dimension two, as suggested by some\nearlier lattice studies, but we do find a contribution from a dimension four\ncondensate. The value of this condensate is approximately 0.04(1) GeV^4, but\nwith large uncertainties."
    },
    {
        "anchor": "Three pion spectrum in the $I=3$ channel from lattice QCD: Three-body states are critical to the dynamics of many hadronic resonances.\nWe show that lattice QCD calculations have reached a stage where these states\ncan be accurately resolved. We perform a calculation over a wide range of\nparameters and find all states below inelastic threshold agree with predictions\nfrom a state-of-the-art phenomenological formalism. This also illustrates the\nreliability of the formalism used to connect lattice QCD results to infinite\nvolume physics. Our calculation is performed using three positively charged\npions, with different lattice geometries and quark masses.",
        "positive": "A Study of Finite Temperature Gauge Theory in (2+1) Dimensions: We determine the critical couplings and the critical exponents of the finite\ntemperature transition in SU(2) and SU(3) pure gauge theory in (2+1)\ndimensions. We also measure Wilson loops at $T=0$ on a wide range of $\\beta$\nvalues using APE smearing to improve the signal. We extract the string tension\n$\\sigma$ from a fit to large distances, including a string fluctuation term.\nWith these two entities we calculate $T_c/\\sqrt{\\sigma}$."
    },
    {
        "anchor": "Latest results from lattice QCD for exotic hybrid mesons: I review the results from lattice gauge theory for the masses of exotic\nhybrid mesons.",
        "positive": "Dynamic Critical Behaviour of Wolff's Algorithm for $RP^N$\n  $\u03c3$-Models: We study the performance of a Wolff-type embedding algorithm for $RP^N$\n$\\sigma$-models. We find that the algorithm in which we update the embedded\nIsing model \\`a la Swendsen-Wang has critical slowing-down as $z_\\chi \\approx\n1$. If instead we update the Ising spins with a perfect algorithm which at\nevery iteration produces a new independent configuration, we obtain $z_\\chi\n\\approx 0$. This shows that the Ising embedding encodes well the collective\nmodes of the system, and that the behaviour of the first algorithm is connected\nto the poor performance of the Swendsen-Wang algorithm in dealing with a\nfrustrated Ising model."
    },
    {
        "anchor": "Supersymmetry on the lattice and the status of the Super-Yang-Mills\n  simulations: Supersymmetry (SUSY) and supersymmetric field theories are an interesting\ntopic for numerical lattice simulations. Similar to the chiral symmetry there\nis also no local realization of (interacting) supersymmetry on the lattice. I\nbriefly review the basic reasons for the breaking of supersymmetry. One attempt\nto solve the problem uses a Ginsparg-Wilson relation for supersymmetry.\nHowever, apart from the free theory, a solution of this relation has so far not\nbeen found. For supersymmetric Yang-Mills (SYM) theory a fine-tuning of the\nbare gluino mass is enough to arrive at a supersymmetric continuum limit. The\nlast part of this work contains a short status report of recent SYM\nsimulations.",
        "positive": "Link smearing considered as MCRG transformation: Gauge link smearing is widely used in lattice QCD computations. The idea is\nto remove the local (UV) fluctuations of the gauge field configurations while\nkeeping the longer-range (IR) properties intact. Important applications are in\nthe definitions of interpolating hadron operators as well as in updating the\ngauge field configurations with dynamical quarks in the so-called Hybrid Monte\nCarlo (HMC) algorithm. Here we study the effectiveness of various smearing\nmethods and try to quantify these with tools known from Monte Carlo\nRenormalization Group (MCRG)."
    },
    {
        "anchor": "High Precision Statistical Landau Gauge Lattice Gluon Propagator\n  Computation vs. the Gribov-Zwanziger approach: The compatibility of the results from the Gribov-Zwanziger tree level\nprediction and lattice simulations, using large statistical ensembles, for the\nLandau gauge gluon propagator are investigated, thereby complementing earlier\nwork using small-scale statistics. Our results show that the data is well\ndescribed by the tree level estimate only up to momenta $p \\lesssim 1$ GeV\nwhile clearly favoring the so-called Refined Gribov-Zwanziger scenario,\nimplying particular relations between certain possible $d=2$ condensates. We\nalso provide a global fit of the lattice data which interpolates between the\nabove scenario at low momenta and the usual continuum one-loop renormalization\nimproved perturbation theory after introducing an infrared log-regularizing\nterm.",
        "positive": "Inverse Symmetry Breaking on the lattice: an accurate MC study: We present here a new MC study of ISB at finite temperature in a $Z_2\\times\nZ_2$ $\\lambda\\phi^4$ model in four dimensions. The results of our simulations,\neven if not conclusive, are favourable to ISB. Detection of the effect required\nmeasuring some critical couplings with six-digits precision, a level of\naccuracy that could be achieved only by a careful use of FSS techniques. The\ngap equations for the Debye masses, resulting from the resummation of the ring\ndiagrams, seem to provide a qualitatively correct description of the data,\nwhile the simple one-loop formulae appear to be inadequate."
    },
    {
        "anchor": "A generalized model for two dimensional quantum gravity and dynamics of\n  random surfaces for d>1: The possible interpretations of a new continuum model for the two-dimensional\nquantum gravity for $d>1$ ($d$=matter central charge), obtained by carefully\ntreating both diffeomorphism and Weyl symmetries, are discussed. In particular\nwe note that an effective field theory is achieved in low energy (large area)\nexpansion, that may represent smooth self-avoiding random surfaces embedded in\na $d$-dimensional flat space-time for arbitrary $d$. Moreover the values of\nsome critical exponents are computed, that are in agreement with some recent\nnumerical results.",
        "positive": "Coherent Topological Charge Structure in $CP^{N-1}$ Models and QCD: In an effort to clarify the significance of the recent observation of\nlong-range topological charge coherence in QCD gauge configurations, we study\nthe local topological charge distributions in two-dimensional $CP^{N-1}$ sigma\nmodels, using the overlap Dirac operator to construct the lattice topological\ncharge. We find long-range sign coherence of topological charge along extended\none-dimensional structures in two-dimensional spacetime. We discuss the\nconnection between the long range topological structure found in $CP^{N-1}$ and\nthe observed sign coherence along three-dimensional sheets in four-dimensional\nQCD gauge configurations. In both cases, coherent regions of topological charge\nform along membrane-like surfaces of codimension one. We show that the Monte\nCarlo results, for both two-dimensional and four-dimensional gauge theory,\nsupport a view of topological charge fluctuations suggested by Luscher and\nWitten. In this framework, the observed membranes are associated with\nboundaries between ``k-vacua,'' characterized by an effective local value of\n$\\theta$ which jumps by $\\pm 2\\pi$ across the boundary."
    },
    {
        "anchor": "The pion-nucleon sigma term from Lattice QCD: We summarize recent evidence, both from lattice QCD and chiral perturbation\ntheory, that suggests that larger-than-expected excited-state contamination\ncould be the reason for the tension between phenomenological determinations and\nprevious direct lattice-QCD calculations of the pion--nucleon sigma term\n$\\sigma_{\\pi N}$. In addition, we extend the $\\chi$PT analysis by calculating\nthe corrections due to including the $\\Delta(1232)$ resonance as an explicit\ndegree of freedom. This correction is found to be small, thereby corroborating\nthe excited-state effects found in the $\\Delta$-less calculation and the result\nfor $\\sigma_{\\pi N}$.",
        "positive": "Quantum chaos in QCD and hadrons: This article is the written version of a talk delivered at the Workshop on\nNonlinear Dynamics and Fundamental Interactions in Tashkent and starts with an\nintroduction into quantum chaos and its relationship to classical chaos. The\nBohigas-Giannoni-Schmit conjecture is formulated and evaluated within\nrandom-matrix theory. In accordance to the title, the presentation is twofold\nand begins with research results on quantum chromodynamics and the quark-gluon\nplasma. We conclude with recent research work on the spectroscopy of baryons.\nWithin the framework of a relativistic constituent quark model we investigate\nthe excitation spectra of the nucleon and the delta with regard to a possible\nchaotic behavior for the cases when a hyperfine interaction of either\nGoldstone-boson-exchange or one-gluon-exchange type is added to the confinement\ninteraction. Agreement with predictions from the experimental hadron spectrum\nis established."
    },
    {
        "anchor": "Transversity GPDs of the proton from lattice QCD: We present the first calculation of the $x$-dependence of the isovector\ntransversity generalized parton distributions (GPDs) for the proton within\nlattice QCD. We compute the matrix elements with non-local operators containing\na Wilson line. The calculation implements the Breit symmetric frame. The proton\nmomenta are chosen as $0.83,\\,1.25,\\,1.67$ GeV, and the values of the momentum\ntransfer squared are $0.69,\\,1.02$ GeV$^2$. These combinations include cases\nwith zero and nonzero skewness. The calculation is performed using one ensemble\nof two degenerate-mass light, a strange and a charm quark of maximally twisted\nmass fermions with a clover term. The lattice results are renormalized\nnon-perturbatively and finally matched to the light-cone GPDs using one-loop\nperturbation theory within the framework of large momentum effective theory.\nThe final GPDs are given in the $\\overline{\\rm MS}$ scheme at a scale of 2 GeV.\nIn addition to the individual GPDs, we form the combination of the transversity\nGPDs that is related to the transverse spin structure of the proton. Finally,\nwe extract the lowest two moments of GPDs and draw a number of important\nqualitative conclusions.",
        "positive": "Long-Distance Nuclear Matrix Elements for Neutrinoless Double-Beta Decay\n  from Lattice QCD: Neutrinoless double-beta ($0\\nu\\beta\\beta$) decay is a heretofore unobserved\nprocess which, if observed, would imply that neutrinos are Majorana particles.\nInterpretations of the stringent experimental constraints on\n$0\\nu\\beta\\beta$-decay half-lives require calculations of nuclear matrix\nelements. This work presents the first lattice quantum-chromodynamics (LQCD)\ncalculation of the matrix element for $0\\nu\\beta\\beta$ decay in a multi-nucleon\nsystem, specifically the $nn \\rightarrow pp ee$ transition, mediated by a light\nleft-handed Majorana neutrino propagating over nuclear-scale distances. This\ncalculation is performed with quark masses corresponding to a pion mass of\n$m_\\pi = 806$ MeV at a single lattice spacing and volume. The statistically\ncleaner $\\Sigma^- \\rightarrow \\Sigma^+ ee$ transition is also computed in order\nto investigate various systematic uncertainties. The prospects for matching the\nresults of LQCD calculations onto a nuclear effective field theory to determine\na leading-order low-energy constant relevant for $0\\nu\\beta\\beta$ decay with a\nlight Majorana neutrino are investigated. This work, therefore, sets the stage\nfor future calculations at physical values of the quark masses that, combined\nwith effective field theory and nuclear many-body studies, will provide\ncontrolled theoretical inputs to experimental searches of $0\\nu\\beta\\beta$\ndecay."
    },
    {
        "anchor": "Shift of Symmetries of Naive Fermions in QCD-like Lattice Theories: We study the global symmetries of naive lattices Dirac operators in QCD-like\ntheories in any dimension larger than two. In particular we investigate how the\nchosen number of lattice sites in each direction affects the global symmetries\nof the Dirac operator. These symmetries are important since they do not only\ndetermine the infra-red spectrum of the Dirac operator but also the symmetry\nbreaking pattern and, thus, the lightest pseudo-scalar mesons. We perform the\nsymmetry analysis and discuss the possible zero modes and the degree of\ndegeneracy of the lattice Dirac operators. Moreover we explicitly identify a\n\"reduced\" lattice Dirac operator which is the naive Dirac operator apart from\nthe degeneracy. We verify our predictions by comparing Monte Carlo simulations\nof QCD-like theories in the strong coupling limit with the corresponding random\nmatrix theories.",
        "positive": "Form factor ratios for $B_s \\rightarrow K \\, \\ell \\, \u03bd$ and $B_s\n  \\rightarrow D_s \\, \\ell \\, \u03bd$ semileptonic decays and $|V_{ub}/V_{cb}|$: We present a lattice quantum chromodynamics determination of the ratio of the\nscalar and vector form factors for two semileptonic decays of the $B_s$ meson:\n$B_s \\rightarrow K \\ell \\nu$ and $B_s \\rightarrow D_s \\ell \\nu$. In conjunction\nwith future experimental data, our results for these correlated form factors\nwill provide a new method to extract $|V_{ub}/V_{cb}|$, which may elucidate the\ncurrent tension between exclusive and inclusive determinations of these\nCabibbo-Kobayashi-Maskawa mixing matrix parameters. In addition to the form\nfactor results, we determine the ratio of the differential decay rates, and\nforward-backward and polarization asymmetries, for the two decays."
    },
    {
        "anchor": "Gauge theories on a five-dimensional orbifold: We present a construction of non-Abelian gauge theories on the R^4 x S^1/Z_2\norbifold. We show that no divergent boundary mass term for the Higgs field,\nidentified with some of the fifth dimensional components of the gauge field, is\ngenerated. The formulation of the theories on the lattice requires only\nDirichlet boundary conditions that specify the breaking of the gauge group. The\nfirst simulations in order to resolve the issue whether these theories can be\nused at low energy as weakly interacting effective theories have been\nperformed. In case of a positive answer, these theories could provide us with a\nnew framework for studying electroweak symmetry breaking.",
        "positive": "Contour deformations for non-holomorphic actions: We show how contour deformations may be used to control the sign problem of\nlattice Monte Carlo calculations with non-holomorphic actions. Such actions\narise naturally in quantum mechanical scattering problems. The approach is\ndemonstrated in conjunction with the holomorphic gradient flow. As our central\nexample we compute the real-time evolution of a particle in a one-dimensional\nanalog of the Yukawa potential."
    },
    {
        "anchor": "The endpoint of the electroweak phase transition: The 3d SU(2)-Higgs model is used to find the critical Higgs mass above which\nthe first order phase transition ends. One method is focused on the\ndisappearance of the two-state signal of the scalar condensate (vanishing of\nthe latent heat). Another method is based on the analysis of Lee-Yang zeroes of\nthe partition function which allows to characterise the change from first order\ntransition into an analytical crossover.",
        "positive": "Testing Dimensional Reduction in SU(2) Gauge Theory: At high temperature, every $(d+1)$-dimensional theory can be reformulated as\nan effective theory in $d$ dimensions. We test the numerical accuracy of this\nDimensional Reduction for (3+1)-dimensional SU(2) by comparing perturbatively\ndetermined effective couplings with lattice results as the temperature is\nprogressively lowered. We observe an increasing disagreement between numerical\nand perturbative values from $T=4 T_c$ downwards, which may however be due to\nsomewhat different implementations of dimensional reduction in the two cases."
    },
    {
        "anchor": "Distribution Functions From Breit-Frame Regularisation: We suggest a new Hamiltonian lattice approach, using a regularisation\nmotivated by deep inelastic scattering. We discuss the relation between\ndistribution functions and the $F_1$ structure function. We have tested this\nmethod by computing the critical behaviour of the scalar model and find\nagreement with scaling behaviour and with results by L\\\"uscher and Weisz.",
        "positive": "Real-time gauge theory simulations from stochastic quantization with\n  optimized updating: We investigate simulations for gauge theories on a Minkowskian space-time\nlattice. We employ stochastic quantization with optimized updating using\nstochastic reweighting or gauge fixing, respectively. These procedures do not\naffect the underlying theory but strongly improve the stability properties of\nthe stochastic dynamics, such that simulations on larger real-time lattices can\nbe performed."
    },
    {
        "anchor": "Lattice QCD study of heavy-heavy-light-light tetraquark candidates: We investigate heavy-light four-quark systems $ud\\bar b \\bar b$ with bottom\nquarks of finite mass which are treated in the framework of NRQCD. We focus on\n$I(J^P)=0(1^+)$, where we recently found evidence for the existence of a\ntetraquark state using static bottom quarks. Furthermore, we report on an\ninvestigation of the $u \\bar d b \\bar b$ four-quark system with quantum numbers\n$I(J^P)=1(1^+)$ again using static bottom quarks.",
        "positive": "Group-theoretical construction of extended baryon operators in lattice\n  QCD: The design and implementation of large sets of spatially-extended,\ngauge-invariant operators for use in determining the spectrum of baryons in\nlattice QCD computations are described. Group-theoretical projections onto the\nirreducible representations of the symmetry group of a cubic spatial lattice\nare used in all isospin channels. The operators are constructed to maximize\noverlaps with the low-lying states of interest, while minimizing the number of\nsources needed in computing the required quark propagators. Issues related to\nthe identification of the spin quantum numbers of the states in the continuum\nlimit are addressed."
    },
    {
        "anchor": "Chiral Lattice Gauge Theories and The Strong Coupling Dynamics of a\n  Yukawa-Higgs Model with Ginsparg-Wilson Fermions: The Yukawa-Higgs/Ginsparg-Wilson-fermion construction of chiral lattice gauge\ntheories described in hep-lat/0605003 uses exact lattice chirality to decouple\nthe massless chiral fermions from a mirror sector, whose strong dynamics is\nconjectured to give cutoff-scale mass to the mirror fermions without breaking\nthe chiral gauge symmetry. In this paper, we study the mirror sector dynamics\nof a two-dimensional chiral gauge theory in the limitof strong Yukawa and\nvanishing gauge couplings, in which case it reduces to an XY model coupled to\nGinsparg-Wilson fermions. For the mirror fermions to acquire cutoff-scale mass\nit is believed to be important that the XY model remain in its \"high\ntemperature\" phase, where there is no algebraic ordering--a conjecture\nsupported by the results of our work. We use analytic and Monte-Carlo methods\nwith dynamical fermions to study the scalar and fermion susceptibilities, and\nthe mirror fermion spectrum. Our results provide convincing evidence that the\nstrong dynamics does not \"break\" the chiral symmetry (more precisely, that the\nmirror fermions do not induce algebraic ordering in two-dimensions), and that\nthe mirror fermions decouple from the infrared physics.",
        "positive": "Quantum Chaos in Physical Systems: from Super Conductors to Quarks: This article is the written version of a talk delivered at the Bexbach\nColloquium of Science 2000 and starts with an introduction into quantum chaos\nand its relationship to classical chaos. The Bohigas-Giannoni-Schmit conjecture\nis formulated and evaluated within random-matrix theory. Several examples of\nphysical systems exhibiting quantum chaos ranging from nuclear to solid state\nphysics are presented. The presentation concludes with recent research work on\nquantum chromodynamics and the quark-gluon plasma. In the case of a chemical\npotential the eigenvalue spectrum becomes complex and one has to deal with\nnon-Hermitian random-matrix theory."
    },
    {
        "anchor": "Computing the Mass of a Magnetic Monopole in SU(2) Gauge Theory: A single magnetic monopole in pure SU(2) gauge theory is simulated on the\nlattice and its mass is computed in the full quantum theory. The results are\nrelevant for our proposed realization of the dual superconductor hypothesis of\nconfinement.",
        "positive": "Precise determination of decay rates for $\u03b7_c \\to \u03b3\u03b3$,\n  $J/\u03c8\\to \u03b3\u03b7_c$ and $J/\u03c8\\to \u03b7_c e^+e^-$ from lattice QCD: We calculate the decay rates for $\\eta_c \\to \\gamma \\gamma$, $J/\\psi \\to\n\\gamma \\eta_c$ and $J/\\psi \\to \\eta_c e^+e^-$ in lattice QCD with $u$, $d$, $s$\nand $c$ quarks in the sea for the first time. We improve significantly on\nprevious theory calculations to achieve accuracies of 1--2\\%, giving lattice\nQCD results that are now more accurate than the experimental values. In\nparticular our results transform the theoretical picture for\n$\\eta_c\\to\\gamma\\gamma$ decays. We use gluon field configurations generated by\nthe MILC collaboration that include $n_f=2+1+1$ flavours of Highly Improved\nStaggered (HISQ) sea quarks at four lattice spacing values from 0.15 fm to 0.06\nfm and with sea u/d masses down to their physical value. We also implement the\nvalence $c$ quarks using the HISQ action. We find ${\\Gamma (\\eta_c \\to \\gamma\n\\gamma) = 6.788(45)_{\\text{fit}}(41)_{\\text{syst}} \\: \\mathrm{keV}}$, in good\nagreement with experimental results using $\\gamma\\gamma \\to \\eta_c \\to\nK\\overline{K}\\pi$ but in 4$\\sigma$ tension with the Particle Data Group global\nfit result; we suggest this fit is revisited. We also calculate $\\Gamma (J/\\psi\n\\to \\gamma \\eta_c) =\n2.219(17)_{\\text{fit}}(18)_{\\text{syst}}(24)_{\\text{expt}}(4)_{\\text{QED}} \\;\n\\mathrm{keV}$, in good agreement with results from CLEO, and predict the Dalitz\ndecay rate $\\Gamma (J/\\psi \\to \\eta_c e^+ e^-) =\n0.01349(21)_{\\text{latt}}(13)_{\\text{QED}} \\; \\mathrm{keV}$. We use our results\nto calibrate other theoretical approaches and to test simple relationships\nbetween the form factors and $J/\\psi$ decay constant expected in the\nnonrelativistic limit."
    },
    {
        "anchor": "QCD thermodynamics with continuum extrapolated Wilson fermions I: QCD thermodynamics is considered using Wilson fermions in the fixed scale\napproach. The temperature dependence of the renormalized chiral condensate,\nquark number susceptibility and Polyakov loop is measured at four lattice\nspacings allowing for a controlled continuum limit. The light quark masses are\nfixed to heavier than physical values in this first study. Finite volume\neffects are ensured to be negligible by using approriately large box sizes. The\nfinal continuum results are compared with staggered fermion simulations\nperformed in the fixed N_t approach. The same continuum renormalization\nconditions are used in both approaches and the final results agree perfectly.",
        "positive": "The quenched glueball spectrum from smeared spectral densities: The standard approach to compute the glueball spectrum on the lattice relies\non the evaluation of effective masses from two-point correlation functions of\noperators with the quantum numbers of the desired state. In this work, we\npropose an alternative procedure, based on the numerical computation of smeared\nspectral densities. Even though the extraction of the latter from lattice\ncorrelators is a notoriously ill-posed inverse problem, we show that a recently\ndeveloped numerical method, based on the Backus-Gilbert regularization,\nprovides a robust way to evaluate a smeared version of the spectral densities.\nFitting the latter to a combination of Gaussians, we extract the masses of the\nlightest glueball and of its first excitation in the spectrum of the theory.\nWhile the preliminary results presented in this contribution are restricted to\nsimulations at finite lattice spacing and finite volume, and for the purely\ngluonic sector of QCD, they represent the first step in a systematic\ninvestigation of glueballs using spectral-reconstruction methods."
    },
    {
        "anchor": "Matching heavy-light currents with NRQCD and HISQ quarks: We calculate the one loop renormalisation parameters for the heavy-light\naxial-vector and vector currents using lattice perturbation theory. We use\nNonRelativistic QCD (NRQCD) heavy quarks and the Highly Improved Staggered\nQuark (HISQ) action for the light quarks. We present results for heavy-light\ncurrents with massless HISQ quarks and briefly discuss the extension to\nheavy-heavy currents with massive HISQ quarks.",
        "positive": "Recent Results in Scalar QED: In this talk we present some recent and new results on the phase structure\nand the continuum limit of lattice formulation of pure gauge QED coupled to\nHiggs fields. We show the presence of second order phase transition lines\nallowing for a continuum limit. Nevertheless, finite size analysis shows that\nthis theory is logarithmically trivial. The role of magnetic monopoles is also\nshown."
    },
    {
        "anchor": "Exotic Tetraquark states with two $\\bar{b}$-quarks and $J^P=0^+$ and\n  $1^+$ $B_s$ states in a nonperturbatively-tuned Lattice NRQCD setup: We use $n_f=2+1$ Wilson-clover gauge-field ensembles from the CLS consortium\nin a Lattice NRQCD setup to predict the binding energy of a $I(J^P)=0(1^+)$\n$ud\\bar{b}\\bar{b}$ tetraquark and a $\\frac{1}{2}(1^+)$ $\\ell s\\bar{b}\\bar{b}$\ntetraquark. We determine the binding energies with respect to the relevant\n$BB^*$ and $B_sB^*$ thresholds respectively to be $112.0(13.2)$ MeV for the\n$ud\\bar{b}\\bar{b}$, and $46.4(12.3)$ MeV for the $\\ell s\\bar{b}\\bar{b}$. We\nalso determine the ground-state $J^P=0^+$ $B_{s0}^*$ and $1^+$ $B_{s1}$ mesons\nto lie $75.4(14.0)$ and $78.7(13.9)$ MeV below the $BK$ and $B^*K$ thresholds\nrespectively. Our errors are entirely dominated by systematics due to\ndiscretisation effects. To achieve these measurements, we performed a neural\nnetwork based nonperturbative tuning of the Lattice NRQCD Hamiltonian's\nparameters against the basic bottomonium spectrum. For all lattice spacings\nconsidered we can reproduce the continuum splittings of low-lying bottomonia.\nIt is worth remarking that our nonperturbative tuning parameters deviate from 1\nby significant amounts, particularly the term $c_2$.",
        "positive": "New results on topological susceptibility in SU(3) gauge theory: We survey recent lattice results on QCD topological properties. The behaviour\nof the topological susceptibility at the deconfining phase transition has been\ndetermined. This advance has been made possible by an i) an improvement of the\ntopological charge operator and ii) a non-perturbative determination of\nrenormalizations."
    },
    {
        "anchor": "The Kentucky Noisy Monte Carlo Algorithm for Wilson Dynamical Fermions: We develop an implementation for a recently proposed Noisy Monte Carlo\napproach to the simulation of lattice QCD with dynamical fermions by\nincorporating the full fermion determinant directly. Our algorithm uses a\nquenched gauge field update with a shifted gauge coupling to minimize\nfluctuations in the trace log of the Wilson Dirac matrix. The details of tuning\nthe gauge coupling shift as well as results for the distribution of noisy\nestimators in our implementation are given. We present data for some basic\nobservables from the noisy method, as well as acceptance rate information and\ndiscuss potential autocorrelation and sign violation effects. Both the results\nand the efficiency of the algorithm are compared against those of Hybrid Monte\nCarlo.\n  PACS Numbers: 12.38.Gc, 11.15.Ha, 02.70.Uu Keywords: Noisy Monte Carlo,\nLattice QCD, Determinant, Finite Density, QCDSP",
        "positive": "The U(1) phase transition on toroidal and spherical lattices: We have studied the properties of the phase transition in the U(1) compact\npure gauge model paying special atention to the influence of the topology of\nthe boundary conditions. From the behavior of the energy cumulants and the\nobservation of an effective \\nu -> 1/d on toroidal and spherical lattices, we\nconclude that the transition is first order."
    },
    {
        "anchor": "An exploratory study of heavy-light semileptonic form factors using\n  distillation: We present our exploratory study with the aim of simulating heavy-light\nsemileptonic form factors as part of the RBC-UKQCD charm (to bottom) physics\nprogramme. We are using a distillation-based setup as a strategy to get\noptimised plateaus in semileptonic $D_{(s)}$ and $B_{(s)}$ decays, and compare\nour results to form factors obtained from sequential $Z_2$-Wall propagators.\nThe study is done in a centre-of-mass frame as well as in several moving\nframes. We use an $N_f=2+1$ domain wall fermion ensemble with a pion mass of\n$340$ MeV, with the aim of extending the study to a variety of other\ndomain-wall ensembles, including physical-pion mass ensembles.",
        "positive": "O(a)-improved quark action on anisotropic lattices and perturbative\n  renormalization of heavy-light currents: We investigate the Symanzik improvement of the Wilson quark action on\nanisotropic lattices. Taking first a general action with nearest-neighbor and\nclover interactions, we study the mass dependence of the ratio of the hopping\nparameters, the clover coefficients, and an improvement coefficient for\nheavy-light vector and axial vector currents. We show how tree-level\nimprovement can be achieved. For a particular choice of the spatial Wilson\ncoupling, the results simplify, and $O(m_0a_\\tau)$ improvement is possible.\n(Here $m_0$ is the bare quark mass and $a_\\tau$ the temporal lattice spacing.)\nWith this choice we calculate the renormalization factors of heavy-light\nbilinear operators at one-loop order of perturbation theory employing the\nstandard plaquette gauge action."
    },
    {
        "anchor": "Phase Structure of Dynamical Triangulation Models in Three Dimensions: The dynamical triangulation model of three-dimensional quantum gravity is\nshown to have a line of transitions in an expanded phase diagram which includes\na coupling mu to the order of the vertices. Monte Carlo renormalization group\nand finite size scaling techniques are used to locate and characterize this\nline. Our results indicate that for mu < mu1 ~ -1.0 the model is always in a\ncrumpled phase independent of the value of the curvature coupling. For mu < 0\nthe results are in agreement with an approximate mean field treatment. We find\nevidence that this line corresponds to first order transitions extending to\npositive mu. However, the behavior appears to change for mu > mu2 ~ 2-4. The\nsimplest scenario that is consistent with the data is the existence of a\ncritical end point.",
        "positive": "Phases at finite winding number of an Abelian lattice gauge theory: Pure gauge theories are rather different from theories with pure scalar and\nfermionic matter, especially in terms of the nature of excitations. For\nexample, in scalar and fermionic theories, one can create ultra-local\nexcitations. For a gauge theory, such excitations need to be closed loops that\ndo not violate gauge invariance. In this proceedings, we present a study on the\ncondensation phenomenon associated with the string-like excitations of an\nAbelian lattice gauge theory. These phenomena are studied through numerical\nsimulations of a $U(1)$ quantum link model in 2+1 dimensions in a ladder\ngeometry using matrix product states. In this proceedings, we show the\nexistence of ground states characterized by the presence of such string-like\nexcitations. These are caused due to the condensation of torelons. We also\nstudy the relationship between the properties of the plaquettes in the ground\nstate and the presence of such condensation phenomenon."
    },
    {
        "anchor": "Finite size effects on $M_\u03c0$ in QCD from Chiral Perturbation Theory: We present a determination of the shift $M_\\pi(L)-M_\\pi$ due to the finite\nspatial box size $L$ by means of $N_f=2$ Chiral Perturbation Theory and\nL\\\"uscher's formula. The range of applicability of the chiral prediction is\ndiscussed.",
        "positive": "Non-perturbative determination of the axial current normalization\n  constant in O(a) improved lattice QCD: A finite-size technique is employed to compute the normalization constant\n$Z_A$ of the isovector axial current in lattice QCD. The calculation is carried\nout in the quenched approximation for values of the bare gauge coupling $g_0$\nranging from 0 to 1. In the lattice action and the lattice expression for the\naxial current we include the counterterms required for O(a) improvement, with\nnon-perturbatively determined coefficients. With little additional work the\nnormalization constant $Z_V$ of the improved isospin current is also obtained."
    },
    {
        "anchor": "Type of dual superconductivity for $SU(2)$ and $SU(3)$ Yang--Mills\n  theories: We investigate the type of dual superconductivity responsible for quark\nconfinement. For this purpose, we solve the field equations of the $U(1)$\nAbelian--Higgs model to obtain the static vortex solution in the whole range\nwithout restricting to the long-distance region. Then we use the resulting\nmagnetic field of the vortex to fit the gauge-invariant chromoelectric field\nconnecting a pair of quark and antiquark which was measured by numerical\nsimulations for $SU(2)$ and $SU(3)$ Yang--Mills theories on a lattice. This\nresult improves the accuracy of the fitted value for the Ginzburg--Landau\nparameter to reconfirm the type I dual superconductivity for quark confinement,\nwhich was claimed by preceding works based on an approximate method based on\nthe Clem ansatz. Moreover, we calculate the Maxwell stress tensor for the\nfitted model to obtain the distribution of the force around the flux tube. This\nsuggests that the attractive force acts on the surface perpendicular to the\nchromoelectric flux tube, in agreement with the type I dual superconductivity.",
        "positive": "I=2 Pion Scattering Length and Phase Shift with Wilson Fermions: We present preliminary results of scattering length and phase shift for I=2\nS-wave $\\pi\\pi$ system with the Wilson fermions in the quenched approximation.\nThe finite size method presented by L\\\"uscher is employed, and calculations are\ncarried out at $\\beta=5.9$ on a $24^3\\times 60$ and $32^3\\times 60$ lattice."
    },
    {
        "anchor": "Topological Lattice Actions for the 2d XY Model: We consider the 2d XY Model with topological lattice actions, which are\ninvariant against small deformations of the field configuration. These actions\nconstrain the angle between neighbouring spins by an upper bound, or they\nexplicitly suppress vortices (and anti-vortices). Although topological actions\ndo not have a classical limit, they still lead to the universal behaviour of\nthe Berezinskii-Kosterlitz-Thouless (BKT) phase transition - at least up to\nmoderate vortex suppression. Thus our study underscores the robustness of\nuniversality, which persists even when basic principles of classical physics\nare violated. In the massive phase, the analytically known Step Scaling\nFunction (SSF) is reproduced in numerical simulations. In the massless phase,\nthe BKT value of the critical exponent eta_c is confirmed. Hence, even though\nfor some topological actions vortices cost zero energy, they still drive the\nstandard BKT transition. In addition we identify a vortex-free transition\npoint, which deviates from the BKT behaviour.",
        "positive": "QCD Lambda parameter from Landau-gauge gluon and ghost correlations: We utilise a recently developed minimal MOM scheme to determine the QCD\nLambda parameter from the gluon and ghost propagators in lattice Landau gauge.\nWe discuss uncertainties in the analysis and report our preliminary zero and\ntwo flavour results, which are r_0*LambdaMS^{(0)}=0.62(1) and\nr_0*LambdaMS^{(2)}=0.60(3)(2), with the second error due to an extrapolation\nuncertainty."
    },
    {
        "anchor": "The lattice infrared Landau gauge gluon propagator: the infinite volume\n  limit: We report on the infrared behaviour of the lattice gluon propagator. The\nbounds on D(0) and their behaviour with the lattice volume are investigated,\ntogether with the full propagator. Moreover, a study of the gluon propagator\nusing different lattice spacings is carried out.",
        "positive": "A composite massless vector boson: In a non-perturbative gauge-invariant formulation of grand-unified theories\nall low energy vector states need to be composite with respect to the\nhigh-scale gauge group, including the photon. We investigate this by using\nlattice methods to spectroscopically analyze the vector channel in a toy\ngrand-unified theory, an SU(2) adjoint Higgs model. Our results support indeed\nthe existence of a massless composite vector particle."
    },
    {
        "anchor": "Towards $K\u03c0$ scattering with domain-wall fermions at the physical\n  point using distillation: Resonances play an important role in Standard Model phenomenology. In\nparticular, hadronic resonances feature in $B$ and $D$ decays, which can be\ncentral for New Physics searches. Lattice QCD simulations combined with the\nfinite-volume method can nowadays be used to reliably study strongly coupled\nscattering processes such as $K\\pi$ and thus the hadronic resonance $K^*$. In\nthis work, we approach $K\\pi$ scattering on a domain-wall $N_f = 2+1$ RBC-UKQCD\nensemble at a physical pion mass. We use the distillation method within Grid\nand Hadrons software to compute sets of operator basis. That allows solving an\neigenvalue problem to extract the low-energy finite-volume spectra, which are\nthen translated into scattering information. We update the state of the\ncalculation by reviewing the smearing process, outlining the variational\nanalysis and concluding by showing preliminary data.",
        "positive": "Automatic O$(a)$ improvement for twisted-mass QCD: We present a condition for automatic O$(a)$ improvement in twisted mass\nlattice QCD, using symmetries of the Symanzik effective theory. If the\ncontinuum part of the Symanzik effective theory is invariant under a particular\ntransformation, named $T_1$ in this report, scaling violations of all\nquantities invariant under $T_1$ transformation are even in the lattice spacing\n$a$. On the other hand, quantities non-invariant under $T_1$ vanish in the\ncontinuum limit with odd powers in $a$. We prove this statement even for the\nmassive case without using the equation of motion. We also consider a few\ndifferent criteria for the $T_1$ invariant condition in lattice theories and\ndiscuss ambiguities of the lattice condition for O$(a)$ improvement."
    },
    {
        "anchor": "Perturbative Study of the Supersymmetric Lattice Model from Matrix Model: We study the lattice model for the supersymmetric Yang-Mills theory in two\ndimensions proposed by Cohen, Kaplan, Katz, and Unsal. We re-examine the formal\nproof for the absence of susy breaking counter terms as well as the stability\nof the vacuum by an explicit perturbative calculation for the case of U(2)\ngauge group. Introducing fermion masses and treating the bosonic zero momentum\nmode nonperturbatively, we avoid the infra-red divergences in the perturbative\ncalculation. As a result, we find that there appear mass counter terms for\nfinite volume which vanish in the infinite volume limit so that the theory\nneeds no fine-tuning.",
        "positive": "Dynamical Twisted Mass Fermions with Light Quarks: We present results of dynamical simulations with 2 flavours of degenerate\nWilson twisted mass quarks at maximal twist in the range of pseudo scalar\nmasses from 300 to 550 MeV. The simulations are performed at one value of the\nlattice spacing a \\lesssim 0.1 fm. In order to have O(a) improvement and aiming\nat small residual cutoff effects, the theory is tuned to maximal twist by\nrequiring the vanishing of the untwisted quark mass. Precise results for the\npseudo scalar decay constant and the pseudo scalar mass are confronted with\nchiral perturbation theory predictions and the low energy constants F,\n\\bar{l}_3 and \\bar{l}_4 are evaluated with small statistical errors."
    },
    {
        "anchor": "A new representation of the Adler function for lattice QCD: We address several aspects of lattice QCD calculations of the hadronic vacuum\npolarization and the associated Adler function. We implement a representation\nderived previously which allows one to access these phenomenologically\nimportant functions for a continuous set of virtualities, irrespective of the\nflavor structure of the current. Secondly we present a theoretical analysis of\nthe finite-size effects on our particular representation of the Adler function,\nbased on the operator product expansion at large momenta and on the spectral\nrepresentation of the Euclidean correlator at small momenta. Finally, an\nanalysis of the flavor structure of the electromagnetic current correlator is\nperformed, where a recent theoretical estimate of the Wick-disconnected diagram\ncontributions is rederived independently and confirmed.",
        "positive": "Neutral mesons and disconnected diagrams in Twisted Mass QCD: We evaluate properties of neutral mesons in Nf=2 dynamical simulations of\nTMQCD at maximal twist. The pion is explored - establishing the size of the\nisospin splitting (an order a^2 effect). We investigate the eta' (the Nf=2\nflavour singlet pseudoscalar meson) and neutral rho and scalar mesons. We show\nthat disconnected diagrams can be evaluated very efficiently in TMQCD using\nvariance reduction methods."
    },
    {
        "anchor": "Indirect lattice evidence for the Refined Gribov-Zwanziger formalism and\n  the gluon condensate $\\braket{A^2}$ in the Landau gauge: We consider the gluon propagator $D(p^2)$ at various lattice sizes and\nspacings in the case of pure SU(3) Yang-Mills gauge theories using the Landau\ngauge fixing. We discuss a class of fits in the infrared region in order to\n(in)validate the tree level analytical prediction in terms of the (Refined)\nGribov-Zwanziger framework. It turns out that an important role is played by\nthe presence of the widely studied dimension two gluon condensate\n$\\braket{A^2}$. Including this effect allows to obtain an acceptable fit up to\n1 \\'{a} 1.5 GeV, while corroborating the Refined Gribov-Zwanziger prediction\nfor the gluon propagator. We also discuss the infinite volume extrapolation,\nleading to the estimate $D(0)=8.3\\pm0.5\\text{GeV}^{-2}$. As a byproduct, we can\nalso provide the prediction $\\braket{g^2 A^2}\\approx 3\\text{GeV}^2$ obtained at\nthe renormalization scale $\\mu=10\\text{GeV}$.",
        "positive": "Non-perturbative O(a) improvement of lattice QCD: The coefficients multiplying the counterterms required for O($a$) improvement\nof the action and the isovector axial current in lattice QCD are computed\nnon-perturbatively, in the quenched approximation and for bare gauge couplings\n$g_0$ in the range $0 \\leq g_0 \\leq 1$. A finite-size method based on the\nSchr\\\"odinger functional is employed, which enables us to perform all\ncalculations at zero or nearly zero quark mass. As a by-product the critical\nhopping parameter $\\kappa_c$ is obtained at all couplings considered."
    },
    {
        "anchor": "Lattice QCD at finite isospin density: We have simulated QCD at a finite chemical potential $\\mu_I$ for isospin\n($I_3$) to probe part of the phase diagram for nuclear matter. Preliminary\nresults suggest that for $\\mu_I > \\mu_c$, this theory forms a charged pion\ncondensate which spontaneously breaks $I_3$, and the isospin density is non\nzero.",
        "positive": "Quantum phase transition of high dimensional Yang-Mills theories: We determine the critical value of the coupling where the first order quantum\nphase transition takes place for lattice SU(2) Yang-Mills theories in\ndimensions higher than four. Within a Mean-Field approach we derive an\napproximate law valid for any dimension d and in the context of a Monte Carlo\napproach, in addition to the already known d=5 case, we look at d=6,7,8."
    },
    {
        "anchor": "A New Method for Determining $F_\u03c0$ on the Lattice: We derive the two-point spectral correlation function of the Dirac operator\nwith a specific external source in the $\\epsilon$-regime of QCD. This\ncorrelation function has a unique and strong dependence on $F_\\pi$, and thus\nprovides an novel way to extract $F_\\pi$ from lattice simulations. We test the\nmethod in a quenched lattice simulation with staggered fermions.",
        "positive": "Isospin susceptibility in the O($n$) sigma-model in the delta-regime: We compute the isospin susceptibility in an effective O($n$) scalar field\ntheory (in $d=4$ dimensions), to third order in chiral perturbation theory\n($\\chi$PT) in the delta--regime using the quantum mechanical rotator picture.\nThis is done in the presence of an additional coupling, involving a parameter\n$\\eta$, describing the effect of a small explicit symmetry breaking term (quark\nmass). For the chiral limit $\\eta=0$ we demonstrate consistency with our\nprevious $\\chi$PT computations of the finite-volume mass gap and isospin\nsusceptibility. For the massive case by computing the leading mass effect in\nthe susceptibility using $\\chi$PT with dimensional regularization, we determine\nthe $\\chi$PT expansion for $\\eta$ to third order. The behavior of the shape\ncoefficients for long tube geometry obtained here might be of broader interest.\nThe susceptibility calculated from the rotator approximation differs from the\n$\\chi$PT result in terms vanishing like $1/\\ell$ for $\\ell=L_t/L_s\\to\\infty$.\nWe show that this deviation can be described by a correction to the rotator\nspectrum proportional to the square of the quadratic Casimir invariant."
    },
    {
        "anchor": "Phase diagram near the quantum critical point in Schwinger model at\n  $\u03b8= \u03c0$: analogy with quantum Ising chain: The Schwinger model, one-dimensional quantum electrodynamics, has CP symmetry\nat $\\theta = \\pi$ due to the topological nature of the $\\theta$ term. At zero\ntemperature, it is known that as increasing the fermion mass, the system\nundergoes a second-order phase transition to the CP broken phase, which belongs\nto the same universality class as the quantum Ising chain. In this paper, we\nobtain the phase diagram near the quantum critical point (QCP) in the\ntemperature and fermion mass plane using first-principle Monte Carlo\nsimulations, while avoiding the sign problem by using the lattice formulation\nof the bosonized Schwinger model. Specifically, we perform a detailed\ninvestigation of the correlation function of the electric field near the QCP\nand find that its asymptotic behavior can be described by the universal scaling\nfunction of the quantum Ising chain. This finding indicates the existence of\nthree regions near the QCP, each characterized by a specific asymptotic form of\nthe correlation length, and demonstrates that the CP symmetry is restored at\nany nonzero temperature, entirely analogous to the quantum Ising chain. The\nrange of the scaling behavior is also examined and found to be particularly\nwide.",
        "positive": "Effect of Improving the Lattice Gauge Action on QCD Topology: We use lattice topology as a laboratory to compare the Wilson action (WA)\nwith the Symanzik-Weisz (SW) action constructed from a combination of (1x1) and\n(1x2) Wilson loops, and the estimate of the renormalization trajectory (RT)\nfrom a renormalization group transformation (RGT) which also includes higher\nrepresentations of the (1x1) loop. Topological charges are computed using the\ngeometric (L\\\"uscher's) and plaquette methods on the uncooled lattice, and also\nby using cooling to remove ultraviolet artifacts. We show that as the action\nimproves by approaching the RT, the topological charges for individual\nconfigurations computed using these three methods become more highly\ncorrelated, suggesting that artificial lattice renormalizations to the\ntopological susceptibility can be suppressed by improving the action."
    },
    {
        "anchor": "Magnetic Susceptibility of Strongly Interacting Matter across the\n  Deconfinement Transition: We propose a method to determine the total magnetic susceptibility of\nstrongly interacting matter by lattice QCD simulations, and present first\nnumerical results for the theory with two light flavors, which suggest a weak\nmagnetic activity in the confined phase and the emergence of strong\nparamagnetism in the deconfined, Quark-Gluon Plasma phase.",
        "positive": "Critical behaviour of random walks: We have numerically studied the trapping problem in a two-dimensional lattice\nwhere particles are continuously generated. We have introduced interaction\nbetween particles and directionality of their movement. This model presents a\ncritical behaviour with a rich phase structure similar to spin systems. We\ninterpret a change in the asymptotic density of particles as a phase\ntransition. For high directionality the change is abrupt, possibly of first\norder. For small directionality the phase transition is of higher order. We\nhave computed the phase diagram, the volume dependence of the critical point,\nand the relaxation time of the system in the large volume limit."
    },
    {
        "anchor": "Colour fields of the quark-antiquark excited flux tube: We present colour field density profiles for some of the first SU(3) gluonic\nexcitations of the flux tube in the presence of a static quark-antiquark pair.\nThe results are obtained from a large set of gluonic operators.",
        "positive": "Large-Flavor QCD on the Lattice: We study the nature of the QCD vacuum at general number of flavors $N_F$ by\nnumerical simulations on the lattice. Combining the results with those of the\nperturbation theory, we propose the following picture: 1) For $N_F \\ge 17$,\nthere exists only one IR fixed point at vanishing gauge coupling, i.e., the\ntheory in the continuum limit is trivial. 2) For $16 \\ge N_F \\ge 7$, there is a\nnon-trivial fixed point. Therefore, the theory is non-trivial with anomalous\ndimensions, however, without quark confinement. 3) For $N_F \\le 6$, theories\nsatisfy both quark confinement and spontaneous chiral symmetry breaking in the\ncontinuum limit."
    },
    {
        "anchor": "Exploration of the phase diagram of 5D anisotropic SU(2) gauge theory: In this paper we attempt a non-perturbative study of the five dimensional,\nanisotropic SU(2) gauge theory on the lattice using Monte-Carlo techniques. Our\ngoal is the exploration of the phase diagram, define the various phases and the\ncritical boundary lines. Three phases appear, two of them are continuations of\nthe Strong and the Weak coupling phases of pure 4d SU(2) to non-zero coupling\n$\\beta^{'}$ in the fifth transverse direction and they are separated by a\ncrossover transition, while the third phase is a 5D Coulombic phase. We provide\nevidence that the phase transition between the 5D Coulomb phase and the Weak\ncoupling phase is a second order phase transition. Assuming that this result is\nnot altered when increasing the lattice volume we give a first estimate of the\nassociated critical exponents. This opens the possibility for a continuum\neffective five dimensional field theory.",
        "positive": "Reconstruction of light-cone parton distribution functions from lattice\n  QCD simulations at the physical point: We present the unpolarized and helicity parton distribution functions\ncalculated within lattice QCD simulations using physical values of the light\nquark mass. Non-perturbative renormalization is employed and the lattice data\nare converted to the MSbar-scheme at a scale of 2 GeV. A matching process is\napplied together with target mass corrections leading to the reconstruction of\nlight-cone parton distribution functions. For both cases we find a similar\nbehavior between the lattice and phenomenological data, and for the polarized\nPDF a nice overlap for a range of Bjorken-x values. This presents a major\nsuccess for the emerging field of direct calculations of quark distributions\nusing lattice QCD."
    },
    {
        "anchor": "Contents of Lattice 2001 Proceedings: We give here the contents pages for the Proceedings of the Lattice 2001\nconference (19th International Symposium on Lattice Field Theory) that took\nplace in August 2001 in Berlin, Germany. The contents are in HTML form with\nclickable links to the papers that exist on the arXiv, mostly in hep-lat.\n  Corrections and comments should be sent to bunk@physik.hu-berlin.de.",
        "positive": "The Sign Problem is the Solution: The unquenched spectral density of the Dirac operator at $\\mu\\neq0$ is\ncomplex and has oscillations with a period inversely proportional to the volume\nand an amplitude that grows exponentially with the volume. Here we show how the\noscillations lead to the discontinuity of the chiral condensate."
    },
    {
        "anchor": "Quark-gluon vertex with 2 flavours of O(a) improved Wilson fermions: We study the Landau-gauge quark-gluon vertex with 2 flavours of O(a)improved\nWilson fermions, for several lattice spacings and quark masses. In the limit of\nvanishing gluon momentum, we find that all nonzero form factors have a\nsignificant infrared strength, and that the leading form factor lambda_1,\nmultiplying the tree-level vertex structure, is significantly enhanced in the\ninfrared compared to the quenched case. We find that all form factors are\nfurther enhanced in the infrared as the chiral and continuum limits are\napproached.",
        "positive": "Results from the MILC collaboration's SU(3) chiral perturbation theory\n  analysis: We present the status of the MILC collaboration's analysis of the light\npseudoscalar meson sector with SU(3) chiral fits. The analysis includes data\nfrom new ensembles with smaller lattice spacing, smaller light quark masses and\nlighter than physical strange quark masses. Our fits include the NNLO chiral\nlogarithms. We present results for decay constants, quark masses,\nGasser-Leutwyler low energy constants, and condensates in the two- and\nthree-flavor chiral limits."
    },
    {
        "anchor": "Finite temperature QCD in the quark-composites approach: We investigate QCD at finite temperature in the quark composites approach,\nwhich is based on the use of quark composites with hadronic quantum numbers as\nfundamental variables. We find that chiral symmetry restoration and quark\ndeconfinement are one and the same first order phase transition, whose critical\ntemperature, in a one loop approximation, is $T= 2\\sqrt{\\Omega}\n\\rho^{-2}m_{\\pi}$, where $m_{\\pi}$ is the pion mass, $\\Omega=24$ the number of\nup and down quark components, and $\\rho$ a parameter of order 1 whose precise\nvalue can be determined by the study of the pion-pion interaction.",
        "positive": "$B\\to K$ and $D\\to K$ form factors from fully relativistic lattice QCD: We present the result of lattice QCD calculation of the scalar, vector and\ntensor form factors for the $B\\to K\\ell^+\\ell^-$ decay, across the full\nphysical range of momentum transfer. We use the highly improved staggered quark\n(HISQ) formalism for all valence quarks on eight ensembles of gluon field\nconfigurations generated by the MILC collaboration. These include four flavours\nof HISQ quarks in the sea, with three ensembles having the light $u/d$ quarks\nat physical masses. In the first fully relativistic calculation of these form\nfactors, we use the heavy-HISQ method. This allows us to determine the form\nfactors as a function of heavy quark mass from the $c$ to the $b$, and so we\nalso obtain new results for the $D\\to K$ tensor form factor. The advantage of\nthe relativistic formalism is that we can match the lattice weak currents to\ntheir continuum counterparts much more accurately than in previous\ncalculations; our scalar and vector currents are renormalised fully\nnonperturbatively and we use a well-matched intermediate momentum-subtraction\nscheme for our tensor current. Our scalar and vector $B\\to K$ form factors have\nuncertainties of less than 4% across the entire physical $q^2$ range and the\nuncertainty in our tensor form factor is less than 7%. Our heavy-HISQ method\nallows us to map out the dependence on heavy-quark mass of the form factors and\nwe can also see the impact of changing spectator quark mass by comparing to\nearlier HPQCD results for the same quark weak transition but for heavier\nmesons."
    },
    {
        "anchor": "Accurate hadron spectroscopy on blocked configurations by\n  tadpole-renormalized, clover-improved Wilson quark action: We compare the quenched hadron spectrum on blocked and unblocked lattices for\nthe Wilson quark action, the clover action and the tadpole-improved clover\naction. The latter gives a spectrum markedly closer to the original one, even\nthough the cutoff is 1/a ~ 500 Mev.",
        "positive": "The glueball spectrum from an anisotropic lattice study: The spectrum of glueballs below 4 GeV in the SU(3) pure-gauge theory is\ninvestigated using Monte Carlo simulations of gluons on several anisotropic\nlattices with spatial grid separations ranging from 0.1 to 0.4 fm. Systematic\nerrors from discretization and finite volume are studied, and the continuum\nspin quantum numbers are identified. Care is taken to distinguish single\nglueball states from two-glueball and torelon-pair states. Our determination of\nthe spectrum significantly improves upon previous Wilson action calculations."
    },
    {
        "anchor": "Up and down quark masses and corrections to Dashen's theorem from\n  lattice QCD and quenched QED: In a previous letter (arXiv:1306.2287) we determined the isospin mass\nsplittings of the baryon octet from a lattice calculation based on quenched QED\nand $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings down to\n$0.054~\\mathrm{fm}$, lattice sizes up to $6~\\mathrm{fm}$ and average up-down\nquark masses all the way down to their physical value. Using the same data we\ndetermine here the corrections to Dashen's theorem and the individual up and\ndown quark masses. For the parameter which quantifies violations to Dashens's\ntheorem, we obtain $\\epsilon=0.73(2)(5)(17)$, where the first error is\nstatistical, the second is systematic, and the third is an estimate of the QED\nquenching error. For the light quark masses we obtain,\n$m_u=2.27(6)(5)(4)~\\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\\mathrm{MeV}$ in the\n$\\bar{\\mathrm{MS}}$ scheme at $2~\\mathrm{GeV}$ and the isospin breaking ratios\n$m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and\n$Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong\nCP problem by more than $24$ standard deviations.",
        "positive": "More about chiral symmetry restoration at finite temperature in the\n  planar limit: In the planar limit, in the deconfined phase, the Euclidean Dirac operator\nhas a spectral gap around zero. We show that functions of eigenvalues close to\nthe spectral edge, which are independent of common rescalings and shifts gauge\nconfiguration by gauge configuration, have distributions described by a\nGaussian Hermitian matrix model. However, combinations of eigenvalues that are\nscale and shift invariant only on the average, do not match this matrix model."
    },
    {
        "anchor": "Light hadron masses with 4-GeV cutoff and L=2.4fm: We discuss preliminary results from our quenched light hadron mass\ncalculation on a $48^3 \\times 64$ lattice at the coupling of $\\beta = 6.5$.\nStaggered quarks with masses of $m_q = 0.01, 0.005, 0.0025$ and $0.00125$ are\nused.",
        "positive": "Charmed-Baryon Spectroscopy from Lattice QCD with N_f=2+1+1 Flavors: We present the results of a calculation of the positive-parity ground-state\ncharmed-baryon spectrum using 2+1+1 flavors of dynamical quarks. The\ncalculation uses a relativistic heavy-quark action for the valence charm quark,\nclover-Wilson fermions for the valence light and strange quarks, and HISQ sea\nquarks. The spectrum is calculated with a lightest pion mass around 220 MeV,\nand three lattice spacings (a \\approx 0.12 fm, 0.09 fm, and 0.06 fm) are used\nto extrapolate to the continuum. The light-quark mass extrapolation is\nperformed using heavy-hadron chiral perturbation theory up to O(m_pi^3) and at\nnext-to-leading order in the heavy-quark mass. For the well-measured charmed\nbaryons, our results show consistency with the experimental values. For the\ncontroversial J=1/2 Xi_{cc}, we obtain the isospin-averaged value\nM_{Xi_{cc}}=3595(39)(20)(6) MeV (the three uncertainties are statistics,\nfitting-window systematic, and systematics from other lattice artifacts, such\nas lattice scale setting and pion-mass determination), which shows a 1.7 sigma\ndeviation from the experimental value. We predict the yet-to-be-discovered\ndoubly and triply charmed baryons Xi_{cc}^*, Omega_{cc}, Omega_{cc}^* and\nOmega_{ccc} to have masses 3648(42)(18)(7) MeV, 3679(40)(17)(5) MeV,\n3765(43)(17)(5) MeV and 4761(52)(21)(6) MeV, respectively."
    },
    {
        "anchor": "Aspects of lattice N=4 supersymmetric Yang--Mills: Non-perturbative investigations of $\\mathcal N = 4$ supersymmetric\nYang--Mills theory formulated on a space-time lattice have advanced rapidly in\nrecent years. Large-scale numerical calculations are currently being carried\nout based on a construction that exactly preserves a single supersymmetry at\nnon-zero lattice spacing. A recent development is the creation of an improved\nlattice action through a new procedure to regulate flat directions in a manner\ncompatible with this supersymmetry, by modifying the moduli equations. In this\nproceedings I briefly summarize this new procedure and discuss the parameter\nspace of the resulting improved action that is now being employed in numerical\ncalculations.",
        "positive": "Topology of Minimal Walking Technicolor: We perform a lattice study of the topological susceptibility and instanton\nsize distribution of the $\\su{2}$ gauge theory with two adjoint Dirac fermions\n(also known as Minimal Walking Technicolor), which is known to be in the\nconformal window. In the theory deformed with a small mass term, by drawing a\ncomparison with the pure gauge theory, we find that topological observables are\ndecoupled from the fermion dynamics. This provides further evidence for the\ninfrared conformality of the theory. A study of the instanton size distribution\nshows that this quantity can be used to detect the onset of finite size\neffects."
    },
    {
        "anchor": "Twisted mass QCD and the $\u0394I=1/2$ rule: We show that the application of twisted mass QCD (tmQCD) with four (Wilson)\nquark flavours to the computation of lattice weak matrix elements relevant to\n$\\Delta I=1/2$ transitions has important advantages: the renormalisation of $K\n\\to \\pi$ matrix elements does not require the subtraction of other dimension\nsix operators, the divergence arising from the subtraction of lower dimensional\noperators is softened by one power of the lattice spacing and quenched\nsimulations do not suffer from exceptional configurations at small pion mass.\nThis last feature is also retained in the tmQCD computation of $K \\to \\pi\\pi$\nmatrix elements, which, as far as renormalisation and power subtractions are\nconcerned, has properties analogous to the standard Wilson case.",
        "positive": "Note on the Lattice Fermion Chiral Symmetry Group: The group structure of the variant chiral symmetry discovered by Luscher in\nthe Ginsparg-Wilson description of lattice chiral fermions is analyzed. It is\nshown that the group contains an infinite number of linearly independent\nsymmetry generators, and the Lie algebra is given explicitly. CP is an\nautomorphism of the chiral group, and the CP transformation properties of the\nsymmetry generators is found. Features of the currents associated with these\nsymmetries are discussed, including the fact that some different, non-commuting\nsymmetry generators lead to the same Noether current. These strange features\noccur in all implementations of lattice fermions based on the Ginsparg-Wilson\nrelation, including overlap, domain-wall, and perfect-action chiral fermions.\nThe conclusions are illustrated in a solvable example, free overlap fermions."
    },
    {
        "anchor": "Continuous Chiral Transition in Strongly Coupled Compact QED with the\n  Standard Torus Topology: We analyze the phase diagram of compact QED on the torus with a chirally\nsymmetric four fermion interaction added to the usual Wilson action. Inside a\nmean field approximation for the four fermion term, a line of first order phase\ntransitions and another one of second order are found in the $(\\beta, G)$\nplane. Approaching the second order line a continuum limit can be defined.\nCritical exponents vary along this line in a similar way as in the non-compact\nmodel, suggesting that a non trivial interacting continuum theory can be\nconstructed.",
        "positive": "INvestigation Of The Biconjugate Gradient Algorithm For The Inversion Of\n  Fermion Matrices: An algorithm for the numerical inversion of large matrices, the biconjugate\ngradient algorithm (BGA), is investigated in view of its use for Monte Carlo\nsimulations of fermionic field theories. It is compared with the usual\nconjugate gradient algorithm (CGA) and the minimal residue algorithm (MRA)\nwithin a Higgs-Yukawa model including mirror fermions. For this model it can be\nshown that BGA represents an improvement under certain circumstances where the\nother two slow down."
    },
    {
        "anchor": "Elastic s-wave scattering phase shifts and |Vub| from lattice\n  calculations of form factors for exclusive semileptonic decays: Omnes dispersion relations make a connection between form factors for\nexclusive semileptonic decays and phase shifts in the corresponding elastic\nscattering channels. We describe two applications. In the first, we use lattice\nform factor calculations to learn about phase shifts in elastic s-wave\nisospin-1/2 channels for K pi, B pi, D pi and D K scattering. The aim of the\nsecond application is to make the determination of the CKM matrix element\nmagnitude |Vub| from exclusive semileptonic B to pi decays competitive with\nthat from inclusive decays. Here we use many subtractions in an Omnes\ndispersion relation to motivate a simple fitting function, allowing data to\nconstrain the q^2 shape of the differential decay rate and theory, primarily\nlattice results, to provide normalisation via form factor values.",
        "positive": "Pseudovector meson with strangeness and closed-charm: We investigate the mass spectrum of 1^{+} exotic mesons with quark content\n(\\c\\s\\cbar\\qbar) or (\\c\\q\\cbar\\sbar), using molecular and diquark-antidiquark\noperators, in quenched lattice QCD with exact chiral symmetry. For the\nmolecular operator\n{(\\qbar\\gamma_i\\c)(\\cbar\\gamma_5\\s)-(\\cbar\\gamma_i\\s)(\\qbar\\gamma_5\\c)} and the\ndiquark-antidiquark operator {(\\q^T C \\gamma_i \\c)(\\sbar C \\gamma_5 \\cbar^T)-\n(\\q^T C \\gamma_5 \\c)(\\sbar C \\gamma_i^T \\cbar^T)}, both detect a 1^{+}\nresonance with mass around 4010 +- 50 MeV in the limit m_q -> m_{u,d}."
    },
    {
        "anchor": "One-loop matching coefficients for improved staggered bilinears: We calculate one-loop matching factors for bilinear operators composed of\nimproved staggered fermions. We compare the results for different improvement\nschemes used in the recent literature, all of which involve the use of smeared\nlinks. These schemes aim to reduce, though not completely eliminate, O(a^2)\ndiscretization errors. We find that all these improvement schemes substantially\nreduce the size of matching factors compared to unimproved staggered fermions.\nThe resulting corrections are comparable to, or smaller than, those found with\nWilson and domain-wall fermions. In the best case (``Fat-7'' and mean-field\nimproved HYP links) the corrections are 10 % or smaller at 1/a = 2 GeV.",
        "positive": "A Wilson-Yukawa model with a chiral spectrum in 2D: We summarize our recent study of the fermion spectrum in a fermion-scalar 2D\nmodel with a chiral $U(1)_L \\times U(1)_R$ global symmetry. This model is\nobtained from a two-cutoff lattice formulation of a 2D U(1) chiral gauge\ntheory, in the limit of zero gauge coupling. The massless fermion spectrum\nfound deep in the vortex phase is undoubled and chiral."
    },
    {
        "anchor": "Sigma-terms and axial charges for hyperons and charmed baryons: We present results for the $\\sigma$-terms and axial charges for various\nhyperons and charmed baryons using $N_f=2+1+1$ twisted mass fermions. For the\ncomputation of the three-point function we use the fixed current method. For\none of the $N_f=2+1+1$ ensembles with pion mass of 373 MeV we compare the\nresults of the fixed current method with those obtained with a stochastic\nmethod for computing the all-to-all propagator involved in the evaluation of\nthe three point functions.",
        "positive": "Correlated Dirac Eigenvalues and Axial Anomaly in Chiral Symmetric QCD: We investigate the Dirac eigenvalue spectrum ($\\rho(\\lambda,m_l)$) to study\nthe microscopic origin of axial anomaly in high temperature phase of QCD. We\npropose novel relations between the derivatives ($\\partial^n\n\\rho(\\lambda,m_l)/\\partial m_l^n$) of the Dirac eigenvalue spectrum with\nrespect to the quark mass ($m_l$) and the $(n+1)$-point correlations among the\neigenvalues ($\\lambda$) of the massless Dirac operator. Based on these\nrelations, we present lattice QCD results for $\\partial^n\n\\rho(\\lambda,m_l)/\\partial m_l^n$ ($n=1, 2, 3$) with $m_l$ corresponding to\npion masses $m_\\pi=160-55$ MeV, and at a temperature of about 1.6 times the\nchiral phase transition temperature. Calculations were carried out using\n(2+1)-flavors of highly improved staggered quarks and the tree-level Symanzik\ngauge action with the physical strange quark mass, three lattice spacings\n$a=0.12, 0.08, 0.06$ fm, and lattices having aspect ratios $4-9$. We find that\n$\\rho(\\lambda\\to0,m_l)$ develops a peaked structure. This peaked structure,\nwhich arises due to non-Poisson correlations within the infrared part of the\nDirac eigenvalue spectrum, becomes sharper as $a\\to0$, and its amplitude is\nproportional to $m_l^2$. After continuum and chiral extrapolations, we find\nthat the axial anomaly remains manifested in two-point correlation functions of\nscalar and pseudo-scalar mesons in the chiral limit. We demonstrate that the\nbehavior of $\\rho(\\lambda\\to0,m_l)$ is responsible for it."
    },
    {
        "anchor": "Step Scaling with Off Shell Renormalization: A method for computing renormalization constants in the Rome Southampton\nscheme with volume sources and arbitrary momenta is described. This new method\nis found to enable controlled and precise continuum extrapolations and opens\nthe way to compute the running of operators nonperturbatively in the Rome\nSouthampton scheme. We describe this in detail and exhibit several examples of\nlattice step scaling functions.",
        "positive": "Center clusters in full QCD at finite temperature and background\n  magnetic field: We study the center structure of full dynamical QCD at finite temperatures\nand nonzero values of the background magnetic field using continuum\nextrapolated lattice data. We concentrate on two particular observables\ncharacterizing center clusters: their fractality and the probability for\npercolation. For temperatures below and around the transition region, the\nfractal dimension is found to be significantly smaller than three, leading to a\nvanishing mean free path inside the cluster structure. This finding might be\nrelevant for center symmetry-based models of heavy-ion collisions. In addition,\nthe percolation probability is employed to define the transition temperature\nand to map out the QCD phase diagram in the magnetic field-temperature plane."
    },
    {
        "anchor": "Cost-Effective Clustering: Small Beowulf clusters can effectively serve as personal or group\nsupercomputers. In such an environment, a cluster can be optimally designed for\na specific problem (or a small set of codes). We discuss how theoretical\nanalysis of the code and benchmarking on similar hardware lead to optimal\nsystems.",
        "positive": "On temperature dependence of quarkonium correlators: I discuss the temperature dependence of quarkonium correlators calculated in\nlattice QCD. I show that the dominant source of the temperature dependence\ncomes from the zero mode contribution, while the the temperature dependence\nassociated with melting of bound states is quite small. I study the zero mode\ncontribution quantitatively for different quark masses and show that it is well\ndescribed by a quasi-particle model with temperature dependent heavy quark\nmass. As a byproduct an estimate of the medium dependence of the heavy quark\nmass is obtained."
    },
    {
        "anchor": "S-wave scattering of strangeness -3 baryons: We explore the interactions of two strangeness -3 baryons in multiple spin\nchannels with lattice QCD. This system provides an ideal laboratory for\nexploring the interactions of multi-baryon systems with minimal dependence on\nlight quark masses. Model calculations of the two-$\\Omega^-$ system in two\nprevious works have obtained conflicting results, which can be resolved by\nlattice QCD. The lattice calculations are performed using two different volumes\nwith $L\\sim2.5$ and 3.9 fm on anisotropic clover lattices at $m_\\pi \\sim 390$\nMeV with a lattice spacing of $a_s \\sim 0.123$ fm in the spatial direction and\n$a_t\\sim{a}_s/3.5$ in the temporal direction. Using multiple interpolating\noperators from a non-displaced source, we present scattering information for\ntwo ground state $\\Omega^-$ baryons in both the S=0 and S=2 channels. For S=0,\n$k\\cot\\delta$ is extracted at two volumes, which lead to an extrapolated\nscattering length of $a^{\\Omega\\Omega}_{S=0}=0.16 \\pm 0.22 \\ \\text{fm}$,\nindicating a weakly repulsive interaction. Additionally, for S=2, two separate\nhighly repulsive states are observed. We also present results on the\ninteractions of the excited strangeness -3, spin-1/2 states with the ground\nspin-3/2 states for the spin-1 and spin-2 channels. Results for these\ninteractions are consistent with attractive behavior.",
        "positive": "First results with two light flavours of quarks with maximally twisted\n  mass: We report on first results of an ongoing effort to simulate lattice QCD with\ntwo degenerate flavours of quarks by means of the twisted mass formulation\ntuned to maximal twist. By utilising recent improvements of the HMC algorithm,\npseudo-scalar masses well below 300 MeV are simulated on volumes with spatial\nsize larger than 2 fm at values of the lattice spacing similar or smaller than\n0.1 fm. We present first evidence that scaling violations in the pseudo-scalar\ndecay constant are small and well compatible with O(a) improvement.\nAdditionally, exploratory results for the case of N_f=2+1+1 flavours are\ndiscussed."
    },
    {
        "anchor": "The pressure of strong coupling lattice QCD with heavy quarks, the\n  hadron resonance gas model and the large N limit: In this paper we calculate the pressure of pure lattice Yang-Mills theories\nand lattice QCD with heavy quarks by means of strong coupling expansions.\nDynamical fermions are introduced with a hopping parameter expansion, which\nalso allows for the incorporation of finite quark chemical potential. We show\nthat in leading orders the results are in full agreement with expectations from\nthe hadron resonance gas model, thus validating it with a first principles\ncalculation. For pure Yang-Mills theories we obtain the corresponding ideal\nglueball gas, in QCD with heavy quarks our result equals that of an ideal gas\nof mesons and baryons. Another finding is that the Yang-Mills pressure in the\nlarge N limit is of order $\\sim N^0$ to the calculated orders, when the inverse\n't Hooft coupling is used as expansion parameter. This property is expected in\nthe confined phase, where our calculations take place.",
        "positive": "Axial vector form factors in Ds to phi semileptonic decays from lattice\n  QCD: We calculate axial vector and vector form factors for the semileptonic decay\nDs to phi using HISQ valence quarks on MILC ensembles with 2+1 flavours of\nasqtad sea quarks. Using twisted boundary conditions to tune the quarks'\nmomenta, we compute form factors at q^2 = 0 on coarse lattices. We find\nV(0)=0.903(67), A_1(0)= 0.603(20), A_2(0)=0.401(80) and A_0(0)=0.686(17), which\nwe compare to experimental data and previous quenched lattice QCD calculations."
    },
    {
        "anchor": "The hadronic running of the electromagnetic coupling and the electroweak\n  mixing angle from lattice QCD: We compute the hadronic running of the electromagnetic and weak couplings in\nlattice QCD with $N_{\\mathrm{f}}=2+1$ flavors of $\\mathcal{O}(a)$ improved\nWilson fermions. Using two different discretizations of the vector current, we\ncompute the quark-connected and -disconnected contributions to the hadronic\nvacuum polarization (HVP) functions $\\bar{\\Pi}^{\\gamma\\gamma}$ and\n$\\bar{\\Pi}^{\\gamma Z}$ for Euclidean squared momenta $Q^2\\leq\n7\\,\\mathrm{GeV}^2$. Gauge field ensembles at four values of the lattice spacing\nand several values of the pion mass, including its physical value, are used to\nextrapolate the results to the physical point. The ability to perform an exact\nflavor decomposition allows us to present the most precise determination to\ndate of the $\\mathrm{SU}(3)$-flavor-suppressed HVP function $\\bar{\\Pi}^{08}$\nthat enters the running of $\\sin^2\\theta_{\\mathrm{W}}$. Our results for\n$\\bar{\\Pi}^{\\gamma\\gamma}$, $\\bar{\\Pi}^{\\gamma Z}$ and $\\bar{\\Pi}^{08}$ are\npresented in terms of rational functions for continuous values of $Q^2$ below\n$7 \\,\\mathrm{GeV}^2$. We observe a tension of up to $3.5$ standard deviation\nbetween our lattice results for $\\Delta\\alpha^{(5)}_{\\mathrm{had}}(-Q^2)$ and\nestimates based on the $R$-ratio for space-like momenta in the range\n$3$--$7\\,\\mathrm{GeV}^2$. The tension is, however, strongly diminished when\ntranslating our result to the $Z$ pole, by employing the Euclidean split\ntechnique and perturbative QCD, which yields\n$\\Delta\\alpha^{(5)}_{\\mathrm{had}}(M_Z^2)=0.027\\,73(15)$ and agrees with\nresults based on the $R$-ratio within the quoted uncertainties.",
        "positive": "Lattice Analysis of $SU(2)$ with 1 Adjoint Dirac Flavor: Recently $SU(2)$ Yang-Mills theory with one massless adjoint Dirac quark\nflavor emerges as a novel critical theory that can describe the evolution\nbetween a trivial insulator and a topological insulator in AIII class in $3+1$\ndimensions. There are several classes of conjectured infrared dynamics for this\ntheory. One possibility is that the theory undergoes spontaneous chiral\nsymmetry breaking, with two massless Goldstone bosons (the scalar diquark and\nits antiparticle) in the infrared. Another scenario, which is suggested by\nprevious lattice studies by Athenodorou et al., is that the IR sector of the\ntheory is a strongly interacting conformal field theory as the quark mass\nvanishes. The most recent theoretical proposals argue for a case that in the\ninfrared a composite fermion composed of two quarks and an antiquark becomes\nmassless and non-interacting as the quark mass goes to zero, while other\nsectors are decoupled from this low-energy fermion. This work expands upon\nprevious studies by including the composite fermion to investigate which of\nthese three potential scenarios captures the infrared behavior of this theory."
    },
    {
        "anchor": "Application of neural network to sign problem via path optimization\n  method: We introduce the feedforward neural network to attack the sign problem via\nthe path optimization method. The variables of integration is complexified and\nthe integration path is optimized in the complexified space by minimizing the\ncost function which reflects the seriousness of the sign problem. For the\npreparation and optimization of the integral path in multi-dimensional systems,\nwe utilize the feedforward neural network. We examine the validity and\nusefulness of the method in the two-dimensional complex $\\lambda \\phi^4$ theory\nat finite chemical potential as an example of the quantum field theory having\nthe sign problem. We show that the average phase factor is significantly\nenhanced after the optimization and then we can safely perform the hybrid\nMonte-Carlo method.",
        "positive": "Continuum and lattice meson spectral functions at nonzero momentum and\n  high temperature: We analyse discretization effects in the calculation of high-temperature\nmeson spectral functions at nonzero momentum and fermion mass on the lattice.\nWe do so by comparing continuum and lattice spectral functions in the infinite\ntemperature limit. Complete analytical results for the spectral densities in\nthe continuum are presented, along with simple expressions for spectral\nfunctions obtained with Wilson and staggered fermions on anisotropic lattices.\nWe comment on the use of local and point split currents."
    },
    {
        "anchor": "Leading isospin-breaking corrections to meson masses on the lattice: We present a study of the isospin-breaking (IB) corrections to pseudoscalar\n(PS) meson masses using the gauge configurations produced by the ETM\nCollaboration with $N_f=2+1+1$ dynamical quarks at three lattice spacings\nvarying from 0.089 to 0.062 fm. Our method is based on a combined expansion of\nthe path integral in powers of the small parameters $(\\widehat{m}_d -\n\\widehat{m}_u)/\\Lambda_{QCD}$ and $\\alpha_{em}$, where $\\widehat{m}_f$ is the\nrenormalized quark mass and $\\alpha_{em}$ the renormalized fine structure\nconstant. We obtain results for the pion, kaon and $D$-meson mass splitting;\nfor the Dashen's theorem violation parameters\n$\\epsilon_\\gamma(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$, $\\epsilon_{\\pi^0}$,\n$\\epsilon_{K^0}(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$; for the light quark\nmasses $(\\widehat{m}_d - \\widehat{m}_u)(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$,\n$(\\widehat{m}_u / \\widehat{m}_d)(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$; for\nthe flavour symmetry breaking parameters $R(\\overline{\\mathrm{MS}},\n2~\\mbox{GeV})$ and $Q(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$ and for the strong\nIB effects on the kaon decay constants.",
        "positive": "The Structure of the Aoki Phase at Weak Coupling: A new method to determine the phase diagram of certain lattice fermionic\nfield theories in the weakly coupled regime is presented. This method involves\na new type of weak coupling expansion which is multiplicative rather than\nadditive in nature and allows perturbative calculation of partition function\nzeroes. Application of the method to the single flavour Gross-Neveu model gives\na phase diagram consistent with the parity symmetry breaking scenario of Aoki\nand provides new quantitative information on the width of the Aoki phase in the\nweakly coupled sector."
    },
    {
        "anchor": "Monte Carlo simulations and field transformation: the scalar case: We describe a new method in lattice field theory to compute observables at\nvarious values of the parameters lambda_i in the action S[phi,lambda_i].\nFirstly one performs a single simulation of a ``reference action'' S[phi^r,\nlambda_i^r] with fixed lambda_i^r. Then the phi^r-configurations are\ntransformed into those of a field phi distributed according to S[phi,lambda_i],\napart from a ``remainder action'' which enters as a \\break weight. In this way\nwe measure the observables at values of lambda_i different from lambda_i^r. We\nstudy the performance of the algorithm in the case of the simplest\nrenormalizable model, namely the phi^4 scalar theory on a four dimensional\nlattice and compare the method with the ``histogram'' technique of which it is\na generalization.",
        "positive": "Yang-Mills fields and the lattice: The Yang-Mills theory lies at the heart of our understanding of elementary\nparticle interactions. For the strong nuclear forces, we must understand this\ntheory in the strong coupling regime. The primary technique for this is the\nlattice. While basically an ultraviolet regulator, the lattice avoids the use\nof a perturbative expansion. I discuss some of the historical circumstances\nthat drove us to this approach, which has had immense success, convincingly\ndemonstrating quark confinement and obtaining crucial properties of the strong\ninteractions from first principles."
    },
    {
        "anchor": "Pion structure from lattice QCD: We report on the lowest moment of parton distribution functions and\ngeneralized form factors for the pion at several values of the momentum\ntransfer. Calculations are performed for N_f=2 flavors of O(a) improved Wilson\nfermions with pion masses down to 150 MeV.",
        "positive": "Introduction to Lattice QCD: These notes aim to provide a pedagogical introduction to Lattice QCD. The\ntopics covered include the scope of LQCD calculations, lattice discretization\nof gauge and fermion (naive, Wilson, and staggered) actions, doubling problem,\nimproved gauge and Dirac actions, confinement and strong coupling expansions,\nphase transitions in the lattice theory, lattice operators, a general\ndiscussion of statistical and systematic errors in simulations of LQCD, the\nanalyses of the hadron spectrum, glueball masses, the strong coupling constant,\nand the quark masses."
    },
    {
        "anchor": "Mixing of scalar glueballs and flavour-singlet scalar mesons: We discuss in detail the extraction of hadronic mixing strengths from lattice\nstudies. We apply this to the mixing of a scalar glueball and a scalar meson in\nthe quenched approximation. We also measure correlations appropriate for\nflavour-singlet scalar mesons using dynamical quark configurations from UKQCD.\nThis enables us to compare the results from the quenched study of the mixing\nwith the direct determination of the mixed spectrum. Improved methods of\nevaluating the disconnected quark diagrams are also presented.",
        "positive": "Lattice QCD study of the radiative decays $J/\u03c8\\to \u03b7_c\u03b3$ and\n  $h_c\\to \u03b7_c\u03b3$: We present the results of our lattice QCD study of the hadronic matrix\nelements relevant to the physical radiative $J/\\psi\\to \\eta_c\\gamma$ and\n$h_c\\to \\eta_c\\gamma$ decays. We used the twisted mass QCD action with $N_{\\rm\nf}=2$ light dynamical quarks and from the computations made at four lattice\nspacings we were able to take the continuum limit. Besides the form factors\nparameterizing the above decays we also computed: (i) the hyperfine splitting\nand obtained $\\Delta = 112\\pm 4$ MeV, (ii) the annihilation constant\n$f_{J/\\psi}$ which agrees with the one inferred from the measured\n$\\Gamma(J/\\psi \\to e^+e^-)$."
    },
    {
        "anchor": "The Schwinger Model on the lattice in the Microcanonical Fermionic\n  Average approach: The Microcanonical Fermionic Average method has been used so far in the\ncontext of lattice models with phase transitions at finite coupling. To test\nits applicability to Asymptotically Free theories, we have implemented it in\nQED$_2$, \\it i.e.\\rm the Schwinger Model. We exploit the possibility, intrinsic\nto this method, of studying the whole $\\beta, m$ plane at negligible computer\ncost, to follow constant physics trajectories and measure the $m \\to 0$ limit\nof the chiral condensate. We recover the continuum result within 3 decimal\nplaces.",
        "positive": "Anomalies at finite density and chiral fermions: Using perturbation theory in the Euclidean (imaginary time) formalism as well\nas the non-perturbative Fujikawa method, we verify that the chiral anomaly\nequation remains unaffected in the presence of nonzero chemical potential,\n$\\mu$. We extend our considerations to fermions with exact chiral symmetry on\nthe lattice and discuss the consequences for the recent Bloch-Wettig proposal\nfor the Dirac operator at finite chemical potential. We propose a new simpler\nmethod of incorporating $\\mu$ and compare it with the Bloch-Wettig idea."
    },
    {
        "anchor": "Aharonov--Bohm Effect in 3D Abelian Higgs Theory: We study a field--theoretical analogue of the Aharonov--Bohm effect in the 3D\nAbelian Higgs Model: the corresponding topological interaction is proportional\nto the linking number of the vortex and the particle world trajectories. We\nshow that the Aharonov--Bohm effect gives rise to a nontrivial interaction of\ntested charged particles.",
        "positive": "On the Absence of O(a) Errors in Staggered-Quark Discretizations: We demonstrate that the O(a) taste mixing exhibited in standard textbook\npresentations of staggered quarks is an artifact of the particular definition\nof the flavor fields in those presentations, and has nothing to do with the\nunderlying precision of staggered-quark actions, despite continuing comments to\nthe contrary in the current literature. To illustrate this point we introduce a\nnew coordinate-space definition of the flavor fields that suppresses the O(a)\nterm by two additional powers of a. In fact there are no errors at all from\nthis mechanism. The only source of taste mixing comes from the exchange of\nhighly-virtual gluons and enters in O(a^2). We review the idiosyncrasies of\nSymanzik improvement for naive/staggerd-quark actions, and show how these\nresults follow from that program."
    },
    {
        "anchor": "Euclidean Dynamical Triangulation revisited: is the phase transition\n  really first order?: The transition between the two phases of 4D Euclidean Dynamical Triangulation\n[1] was long believed to be of second order until in 1996 first order behavior\nwas found for sufficiently large systems [3,4]. However, one may wonder if this\nfinding was affected by the numerical methods used: to control volume\nfluctuations, in both studies [3,4] an artificial harmonic potential was added\nto the action; in [4] measurements were taken after a fixed number of accepted\ninstead of attempted moves which introduces an additional error. Finally the\nsimulations suffer from strong critical slowing down which may have been\nunderestimated.\n  In the present work, we address the above weaknesses: we allow the volume to\nfluctuate freely within a fixed interval; we take measurements after a fixed\nnumber of attempted moves; and we overcome critical slowing down by using an\noptimized parallel tempering algorithm [6]. With these improved methods, on\nsystems of size up to 64k 4-simplices, we confirm that the phase transition is\nfirst order.",
        "positive": "Is Confinement a Phase of Broken Dual Gauge Symmetry?: We study whether broken dual gauge symmetry, as detected by a monopole order\nparameter introduced by the Pisa group, is necessarily associated with the\nconfinement phase of a lattice gauge theory. We find a number of examples,\nincluding SU(2) gauge-Higgs theory, mixed fundamental-adjoint SU(2) gauge\ntheory, and pure SU(5) gauge theory, which appear to indicate a dual gauge\nsymmetry transition in the absence of a transition to or from a confined phase.\nWhile these results are not necessarily fatal to the dual superconductor\nhypothesis, they may pose some problems of interpretation for the present\nformulation of the Pisa monopole criterion."
    },
    {
        "anchor": "Continuum versus periodic lattice Monte Carlo approach to classical\n  field theory: We compare the momentum space with the standard periodic lattice approach to\nMonte Carlo calculations in classical $\\phi^4$ field theory. We show that the\nmismatch in the initial value of $\\phi^2_{\\text{cl}}(t)$, results in a shift in\nthe ``thermalized'' value, at large times. The two approaches converge to the\nsame result in the continuum limit.",
        "positive": "Discrete Differential Geometry and Lattice Field Theory: We develope a difference calculus analogous to the differential geometry by\ntranslating the forms and exterior derivatives to similar expressions with\ndifference operators, and apply the results to fields theory on the lattice\n[Ref. 1]. Our approach has the advantage with respect to other attempts [Ref.\n2-6] that the Lorentz invariance is automatically preserved as it can be seen\nexplicitely in the Maxwell, Klein-Gordon and Dirac equations on the lattice."
    },
    {
        "anchor": "Large $N$ analysis of the Higgs mass triviality bound: We calculate the triviality bound on the Higgs mass in scalar field theory\nmodels whose global symmetry group $SU(2)_L \\times SU(2)_{\\rm custodial}\n\\approx O(4)$ has been replaced by $O(N)$ and $N$ has been taken to infinity.\nLimits on observable cutoff effects at four percent in several regularized\nmodels with tunable couplings in the bare action yield triviality bounds\ndisplaying a large degree of universality. Extrapolating from $N=\\infty$ to\n$N=4$ we conservatively estimate that a Higgs particle with mass up to\n$0.750~TeV$ and width up to $0.290~TeV$ is realizable without large cutoff\neffects, indicating that strong scalar self interactions in the standard model\nare not ruled out.\n  Note: The full ps file of this preprint is also available via anonymous ftp\nto ftp.scri.fsu.edu. To get the ps file, ftp to this address and use for\nusername \"anonymous\" and for password your name. The file is in the directory\npub/vranas (to go to that directory type: cd pub/vranas) and is called\nlrg_n_hig.ps (to get it type: get lrg_n_hig.ps)",
        "positive": "Chern-Simons term in the 4-dimensional SU(2) Higgs model: Using a variation of Lueschers geometric charge definition for SU(2) lattice\ngauge theory, we have managed to give a geometric expression for it's\nChern-Simons ter. From this definition we have checked the periodic structure.\nwe determined the Chern-Simons density for symmetric and asymmetric lattices\nnear the critical region in the SU(2) Higgs model. The data indicate that\ntunneling is increased at high temperature."
    },
    {
        "anchor": "Parameter dependence of the topology change and the scaling properties\n  of the topology conserving gauge action: The topology conserving gauge action proposed by Luescher is expected to\nreduce the number of non-smooth gauge configurations as well as the topology\nchange compared to the conventional actions for the same lattice spacings. We\nreport our quenched QCD study of the topological stability and the scaling\nviolation of the static quark potential. We find that the the topology change\nis indeed suppressed when the parameter epsilon is of order one. We also find\nthat the scaling violation in the static quark potential remain reasonably\nsmall in the parameter range of our study. Our study is done at the inverse\nlattice spacing a^{-1}=1.4-2.5 GeV with the lattice size L=1.0-1.6fm.",
        "positive": "A lattice QCD calculation of the transverse decay constant of the\n  b1(1235) meson: We review various B meson decays that require knowledge of the transverse\ndecay constant of the b1(1235) meson. We report on an exploratory lattice QCD\ncalculation of the transverse decay constant of the b1 meson. The lattice QCD\ncalculations used unquenched gauge configurations, at two lattice spacings,\ngenerated with two flavours of sea quarks. The twisted mass formalism is used."
    },
    {
        "anchor": "QCD monopoles, abelian projections and gauge invariance: It is shown that the creation of a monopole is a gauge invariant statement,\nbased on topology. Creating a monopole is independent on the abelian projection\nin which it is created. This is fundamental in defining an order parameter for\ndetecting dual superconductivity of the QCD vacuum.",
        "positive": "Topology, the Wilson flow and the HMC algorithm: An old and apparently persistent problem in numerical lattice QCD is that the\nsimulations tend to get trapped in a sector of fixed topological charge when\nthe lattice spacing is taken to zero. The effect sets in very rapidly and may\ninvalidate the simulation results in certain cases. In this talk, the issue is\ndiscussed using the Wilson flow as a tool. The flow has a simple scaling\nbehaviour and allows one to understand how exactly the topological sectors\nemerge in the continuum limit. Further studies however suggest that the\nobserved slowdown of the simulations at small lattice spacings is only partly\ncaused by the emergence of the sectors."
    },
    {
        "anchor": "Quark Mass and Flavour Dependence of the QCD Phase Transition: We analyze the quark mass and flavour dependence of the QCD phase transition\ntemperature. When the lightest pseudo-scalar meson mass (m_PS) is larger than 2\nGeV the critical temperature is controlled by the gluonic sector of QCD alone.\nFor smaller values of the lightest meson mass the pseudo-critical temperature\ndecreases slowly with m_PS. For a large regime of meson masses the\npseudo-critical temperature of 2-flavour QCD is about 10% larger than in the\n3-flavour case. On lattices with temporal extent N_t=4 an extrapolation to the\nchiral limit yields T_c = 173(8) MeV and 154(8) MeV for 2 and 3-flavour QCD,\nrespectively. We also analyze dynamical quark mass effects on the screening of\nthe heavy quark potential. A detailed analysis of the heavy quark free energy\nin 3-flavour QCD shows that close to T_c screening effects are approximately\nquark mass independent already for pseudo-scalar meson masses m_PS = 800 MeV\nand screening sets in at distances r = 0.3 fm.",
        "positive": "Volume dependence of the phase boundary in 4D dynamical triangulation: The number of configurations of the dynamical triangulation model of 4D\neuclidean quantum gravity appears to grow faster than exponentially with the\nvolume, with the implication that the system would end up in the crumpled phase\nfor any fixed $\\kappa_2$ (inverse bare Newton constant). However, a scaling\nregion is not excluded if we allow $\\kappa_2$ to go to infinity together with\nthe volume."
    },
    {
        "anchor": "Improvement and Taste Symmetry Breaking for Staggered Quarks: We compare several improved actions for staggered quarks. We study the effect\nof improvement on the taste changing interactions by calculating the splitting\nin the pion spectrum. We investigate the effect of the improvement on some\ntopological properties.",
        "positive": "Magnetic polarizability of hadrons from lattice QCD in the background\n  field method: We present a calculation of hadron magnetic polarizability using the\ntechniques of lattice QCD. This is carried out by introducing a uniform\nexternal magnetic field on the lattice and measuring the quadratic part of a\nhadron's mass shift. The calculation is performed on a $24^4$ lattice with\nstandard Wilson actions at beta=6.0 (spacing $a=0.1$ fm) and pion mass down to\nabout 500 MeV. Results are obtained for 30 particles covering the entire baryon\noctet ($n$, $p$, $\\Sigma^0$, $\\Sigma^-$, $\\Sigma^+$, $\\Xi^-$, $\\Xi^0$,\n$\\Lambda$) and decuplet ($\\Delta^0$, $\\Delta^-$, $\\Delta^+$, $\\Delta^{++}$,\n$\\Sigma^{*0}$, $\\Sigma^{*-}$, $\\Sigma^{*+}$, $\\Xi^{*0}$, $\\Xi^{*-}$,\n$\\Omega^-$), plus selected mesons ($\\pi^0$, $\\pi^+$, $\\pi^-$, $K^0$, $K^+$,\n${K}^-$, $\\rho^0$, $\\rho^+$, $\\rho^-$, $K^{*0}$, $K^{*+}$, $K^{*-}$). The\nresults are compared with available values from experiments and other\ntheoretical calculations."
    },
    {
        "anchor": "Spin-2 $N\u03a9$ Dibaryon from Lattice QCD: We investigate properties of the $N$(nucleon)-$\\Omega$(Omega) interaction in\nlattice QCD to seek for possible dibaryon states in the strangeness $-3$\nchannel. We calculate the $N\\Omega$ potential through the equal-time\nNambu-Bethe-Salpeter wave function in 2+1 flavor lattice QCD with the\nrenormalization group improved Iwasaki gauge action and the nonperturbatively\n$\\mathcal{O}(a)$ improved Wilson quark action at the lattice spacing $a\\simeq\n0.12$ fm on a (1.9 fm)$^{3}\\times$ 3.8 fm lattice. The $ud$ and $s$ quark\nmasses in our study correspond to $m_{\\pi}= 875(1)$ MeV and $m_{K}= 916(1)$\nMeV. At these parameter values, the central potential in the S-wave with the\nspin 2 shows attractions at all distances.By solving the Schr\\\"{o}dinger\nequation with this potential, we find one bound state whose binding energy is\n$18.9(5.0)(^{+12.1}_{-1.8})$ MeV, where the first error is the statistical one,\nwhile the second represents the systematic error.",
        "positive": "Phase structure of four flavor QCD in the T \u03bcplane from a new method\n  for simulations of lattice gauge theories at non zero baryon density: We review a method for numerical simulations of lattice gauge theories at\nnon-zero baryonic chemical potential we recently proposed. We first report on a\ntest of the method using a solvable model and then present results for the\nphase structure of four flavour QCD. For the first time the region of chemical\npotential up to 1.4 T_C is explored, finding a first order transition line."
    },
    {
        "anchor": "An extension to the Luscher's finite volume method above inelastic\n  threashold (formalism): An extension of the Luscher's finite volume method above inelastic thresholds\nis proposed. It is fulfilled by extendind the procedure recently proposed by\nHAL-QCD Collaboration for a single channel system. Focusing on the asymptotic\nbehaviors of the Nambu-Bethe-Salpeter (NBS) wave functions (equal-time) near\nspatial infinity, a coupled channel extension of effective Schrodinger equation\nis constructed by introducing an energy-independent interaction kernel. Because\nthe NBS wave functions contain the information of T-matrix at long distance,\nS-matrix can be obtained by solving the coupled channel effective Schrodinger\nequation in the infinite volume.",
        "positive": "Electrical conductivity and charge diffusion in thermal QCD from the\n  lattice: We present a lattice QCD calculation of the charge diffusion coefficient, the\nelectrical conductivity and various susceptibilities of conserved charges, for\na range of temperatures below and above the deconfinement crossover. The\ncalculations include the contributions from up, down and strange quarks. We\nfind that the diffusion coefficient is of the order of 1/(2\\pi T) and has a dip\naround the crossover temperature. Our results are obtained with lattice\nsimulations containing 2+1 dynamical flavours on anisotropic lattices. The\nMaximum Entropy Method is used to construct spectral functions from correlators\nof the conserved vector current."
    },
    {
        "anchor": "Gluonic excitation of non-exotic hybrid charmonium from lattice QCD: The ground and first excited states of the hybrid charmonium ${\\bar c} c g$,\nwith non-exotic quantum numbers $J^{PC}=0^{-+}$, $1^{--}$ and $1^{++}$ are\ninvestigated using quenched lattice QCD. They are completely ignored in the\nliterature, only because their ground states are degenerate with $\\eta_c$,\n$J/\\psi$, and $\\chi_{c1}$, and are difficult to be distinguished from these\nconventional charmonium mesons in experiment. However, we observe strong\ngluonic radial excitations in the first excited states; We predict that their\nmasses are 4.352(225)GeV, 4.379(149)GeV and 7.315(257)GeV, completely different\nfrom the first excited states of the corresponding conventional charmonium.\nTheir relevance to the recent discovery of the Y(4260) state and future\nexperimental search for other states are also discussed.",
        "positive": "Exact Local Bosonic Algorithm for Full QCD: We present an exact local bosonic algorithm for the simulation of dynamical\nfermions in lattice QCD. It is based on a non-hermitian polynomial\napproximation of the inverse of the quark matrix and a global Metropolis\naccept/reject correction of the systematic errors. We show that this algorithm\nis a real alternative to the Hybrid Monte Carlo algorithm."
    },
    {
        "anchor": "Subset method for one-dimensional QCD: We present a subset method which solves the sign problem for QCD at nonzero\nquark chemical potential in 0+1 dimensions. The subsets gather gauge\nconfigurations based on the center symmetry of the SU(3) group. We show that\nthe sign problem is solved for one to five quark flavors and that it slowly\nreappears for a larger number of flavors. We formulate an extension of the\ncenter subsets that solves the sign problem for a larger number of flavors as\nwell. We also derive some new analytical results for this toy model.",
        "positive": "Multicanonical hybrid Monte Carlo for compact QED: We demonstrate that substantial progress can be achieved in the study of the\nphase structure of 4-dimensional compact QED by a joint use of hybrid Monte\nCarlo and multicanonical algorithms, through an efficient parallel\nimplementation. This is borne out by the observation of considerable speedup of\ntunnelling between the metastable states, close to the phase transition, on the\nWilson line. Our approach leads to a general parallelization scheme for the\nefficient stochastic sampling of systems where (a part of) the Hamiltonian\ninvolves the total action or energy in each update step."
    },
    {
        "anchor": "Critical Behavior in Nt = 4 Staggered Fermion Thermodynamics: Quantum chromodynamics with two zero-mass flavors is expected to exhibit a\nphase transition with O(4) critical behavior. Fixing the universality class is\nimportant for phenomenology and for facilitating the extrapolation of\nsimulation data to physical quark mass values. Other groups have reported\nresults from lattice QCD simulations with dynamical staggered quarks at Nt = 4,\nwhich suggest a departure from the expected critical behavior. We have pushed\nsimulations to the largest volumes and smallest quark mass to date. Strong\ndiscrepancies in critical exponents and the scaling equation of state persist.",
        "positive": "Status update: $\u03c0^0\\to \u03b3^\\ast \u03b3^\\ast$ transition form factor\n  on CLS ensembles: In this report we present the status of the Mainz group's lattice QCD\ncalculation of the pion transition form factor, which describes the interaction\nof an on-shell pion with two off-shell photons. This form factor is the main\ningredient in the calculation of the pion-pole contribution to hadronic\nlight-by-light scattering in the muon $g-2$. We use the $N_f = 2 + 1$ CLS gauge\nensembles, and we update our previous work by including a physical pion mass\nensemble (E250). We compute the transition form factor in a moving frame as\nwell as in the pion rest frame in order to have access to a wider range of\nphoton virtualities. In addition to the quark-line connected correlator we also\ncompute the quark-line disconnected diagrams that contribute to the form\nfactor. At the final stage of the analysis, the result on E250 will be combined\nwith the previous work published in 2019 to extrapolate the form factor to the\ncontinuum and to physical quark masses."
    },
    {
        "anchor": "LapH interpolating fields with open boundary conditions: The stochastic Laplacian Heaviside (LapH) method has proven to be successful\nin hadronic calculations. In this work, with charm-light spectroscopy in mind,\nwe set up and optimise the LapH procedure limiting ourselves to the evaluation\nof two-point mesonic correlation functions. The calculations are performed on\nCLS ensembles with $N_f=2+1$ Wilson-Clover fermions on a $32^3\\times64$ lattice\nwith open boundary conditions. We analyse the interplay between the LapH\nparameters and the boundary effects, and implement a fitting procedure to\nisolate excitations coming from the border.",
        "positive": "The strange and charm quark contributions to the anomalous magnetic\n  moment (g -2) of the muon from current-current correlators: We describe a new technique (presented in arXiv:1403.1778) to determine the\ncontribution to the anomalous magnetic moment (g-2) of the muon coming from the\nhadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'{e}\napproximants to reconstruct the Adler function from its derivatives at $q^2=0$.\nThese are obtained simply and accurately from time-moments of the vector\ncurrent-current correlator at zero spatial momentum. We test the method using\nstrange quark correlators calculated on MILC Collaboration's $n_f$ = 2+1+1 HISQ\nensembles at multiple values of the lattice spacing, multiple volumes and\nmultiple light sea quark masses (including physical pion mass configurations)."
    },
    {
        "anchor": "On ferrimagnetic phases in chiral Yukawa models: We discuss the phase structure of chiral Yukawa models in the mean-field\napproximation. In particular, we examine under which conditions a ferrimagnetic\nphase appears, by calculating the slopes of possible second order phase\ntransition lines near a critical point. Our results contrast with some\nstatements which appeared in the literature recently.",
        "positive": "Hybrid stochastic method for the tensor renormalization group: We propose a hybrid stochastic method for the tensor renormalization group\n(TRG) approach. TRG is known as a powerful tool to study the many-body systems\nand quantum field theory on the lattice. It is based on a low-rank\napproximation of the tensor using the truncated singular value decomposition\n(SVD), whose computational cost increases as the bond dimension increases, so\nthat efficient cost reduction techniques are highly demanded. We use noise\nvectors for the low-rank approximation with the truncated SVD, by which the\ntruncation error is replaced with a statistical error due to noise, and an\nerror estimation could be improved. We test this method in the classical Ising\nmodel and observe a better accuracy than TRG. We also discuss a cross\ncontamination issue in a multiple use of the same noise vectors, and to remove\nthis systematic error we consider position-dependent noise vectors."
    },
    {
        "anchor": "Small eigenvalues of the staggered Dirac operator in the adjoint\n  representation and Random Matrix Theory: The low-lying spectrum of the Dirac operator is predicted to be universal,\nwithin three classes, depending on symmetry properties specified according to\nrandom matrix theory. The three universal classes are the orthogonal, unitary\nand symplectic ensemble. Lattice gauge theory with staggered fermions has\nverified two of the cases so far, unitary and symplectic, with staggered\nfermions in the fundamental representation of SU(3) and SU(2). We verify the\nmissing case here, namely orthogonal, with staggered fermions in the adjoint\nrepresentation of SU(N_c), N_c=2, 3.",
        "positive": "Tricritical point of lattice QCD with Wilson quarks at finite\n  temperature and density: First principle study of QCD at finite temperature $T$ and chemical potential\n$\\mu$ is essential for understanding a wide range of phenomena from heavy-ion\ncollisions to cosmology and neutron stars. However, in the presence of finite\ndensity, the critical behavior lattice gauge theory without species doubling,\nis unknown. At strong coupling, we examine the phase structure on the $(\\mu,T)$\nplane, using Hamiltonian lattice QCD with Wilson fermions. A tricritical point\nis found, separating the first and second order chiral phase transitions. Such\na tricritical point at finite $T$ has not been found in previous work in the\nHamiltonian formalism with Kogut-Susskind fermions or naive fermions."
    },
    {
        "anchor": "Corrections to the Banks-Casher relation with Wilson quarks: The Banks-Casher relation links the spectral density of the Dirac operator\nwith the existence of a chiral condensate and spontaneous breaking of chiral\nsymmetry. This relation receives corrections from a finite value of the quark\nmass, a finite space-time volume and, if evaluated on a discrete lattice, from\nthe finite value of the lattice spacing a. We present a status report of a\ndetermination of these corrections for Wilson quarks.",
        "positive": "An introduction to lattice QCD at non--zero temperature and density: This is an informal overview of methods and results on the QCD phase diagram\nand lattice termodynamics aimed at specialists in nearby fields."
    },
    {
        "anchor": "Simulating $\\mathbb{Z}_2$ Lattice Gauge Theory with the Variational\n  Quantum Thermalizer: The properties of strongly-coupled lattice gauge theories at finite density\nas well as in real time have largely eluded first-principles studies on the\nlattice. This is due to the failure of importance sampling for systems with a\ncomplex action. An alternative to evade the sign problem is quantum simulation.\nAlthough still in its infancy, a lot of progress has been made in devising\nalgorithms to address these problems. In particular, recent efforts have\naddressed the question of how to produce thermal Gibbs states on a quantum\ncomputer. In this study, we apply a variational quantum algorithm to a\nlow-dimensional model which has a local abelian gauge symmetry. We demonstrate\nhow this approach can be applied to obtain information regarding the phase\ndiagram as well as unequal-time correlation functions at non-zero temperature.",
        "positive": "Phase structure and chiral limit of compact lattice QED with Wilson\n  fermions: We study the phase structure and chiral limit of $4d$ compact lattice QED\nwith Wilson fermions (both dynamical and quenched). We use the standard Wilson\naction (WA) and also the modified action (MA) with some lattice artifacts\nsuppressed. We show that lattice artifacts influence the distributions of\neigenvalues $~\\lambda_i~$ of the fermionic matrix especially for small values\nof $~\\lambda_i~$. Our main conclusion is that the chiral limit of compact QED\ncan be efficiently located using different techniques. Sorry, figures are not\nincluded and can be sent by ordinary mail or Fax."
    },
    {
        "anchor": "Fisher's Zeros and Perturbative Series in Gluodynamics: We study the zeros of the partition function in the complex beta plane\n(Fisher's zeros) in SU(2) and SU(3) gluodynamics. We discuss their effects on\nthe asymptotic behavior of the perturbative series for the average plaquette.\nWe present new methods to infer the existence of these zeros in region of the\ncomplex beta plane where MC reweighting is not reliable. These methods are\nbased on the assumption that the plaquette distribution can be approximated by\na phi^4 type distribution. We give new estimates of the locations for a 4^4\nlattice. For SU(2), we found zeros at beta =2.18(1) \\pm i0.18(2) (which differs\nfrom previous estimates), and at beta =2.18(1) \\pm i0.22(2). For SU(3), we\nconfirm beta =5.54(2)\\pm i0.10(2) and found additional zeros at beta\n=5.54(2)\\pm i0.16(2). Some of the technical material can be found in recent\npreprints, in the following we emphasize the motivations (why it is important\nto know the locations of the zeros) and the challenges (why it is difficult to\nlocate the zeros when the volume increases)",
        "positive": "Trivializing maps, the Wilson flow and the HMC algorithm: In lattice gauge theory, there exist field transformations that map the\ntheory to the trivial one, where the basic field variables are completely\ndecoupled from one another. Such maps can be constructed systematically by\nintegrating certain flow equations in field space. The construction is worked\nout in some detail and it is proposed to combine the Wilson flow (which\ngenerates approximately trivializing maps for the Wilson gauge action) with the\nHMC simulation algorithm in order to improve the efficiency of lattice QCD\nsimulations."
    },
    {
        "anchor": "One-loop effective action for SU(2) gauge theory on S^3: We consider the effective theory for the low-energy modes of SU(2) gauge\ntheory on the three-sphere. By explicitely integrating out the high-energy\nmodes, the one-loop correction to the hamiltonian for this problem is obtained.\nWe calculate the influence of this correction on the glueball spectrum.",
        "positive": "B_K with the Wilson Quark Action: A Non-Perturbative Resolution of\n  Operator Mixing using Chiral Ward Identities: We propose a non-perturbative method to determine the mixing coefficients of\n$\\Delta s=2$ four-quark operators for the Wilson quark action using chiral Ward\nidentities. The method is applied to calculate B_K in quenched QCD."
    },
    {
        "anchor": "Simulations in SO(3) \\times Z(2) lattice gauge theory: We explore simulations on periodic lattices in the Tomboulis $SO(3) \\times\nZ(2)$ formulation. We measure gauge invariant vortex counters for \"thin\",\n\"thick\" and \"hybrid\" vortex sheets in order to tag Wilson loops by the\noccurance of gauge invariant vortices linking them. We also measure projection\nvortex counters defined in the maximal center gauge for comparison.",
        "positive": "Corrections to Scaling and Critical Amplitudes in SU(2) Lattice Gauge\n  Theory: We calculate the critical amplitudes of the Polyakov loop and its\nsusceptibility at the deconfinement transition of SU(2) gauge theory. To this\nend we carefully study the corrections to the scaling functions of the\nobservables coming from irrelevant exponents. As a guiding line for determining\nthe critical amplitudes we use envelope equations derived from the finite size\nscaling formulae for the observables. The equations are then evaluated with new\nhigh precision data obtained on N^3 x 4 lattices for N=12,18,26 and 36. We find\ndifferent correction-to-scaling behaviours above and below the transition. Our\nresult for the universal ratio of the susceptibility amplitudes is\nC_+/C_-=4.72(11) and agrees perfectly with a recent measurement for the 3d\nIsing model."
    },
    {
        "anchor": "Lattice QCD and String Theory: Bosonic string formation in gauge theories is reviewed with particular\nattention to the confining flux in lattice QCD and its string theory\ndescription. Recent results on the Casimir energy of the ground state and the\nstring excitation spectrum are analyzed in the Dirichlet string limit of large\nseparation between static sources. The closed string-soliton (torelon) with\nelectric flux winding around a compact dimension and the three-string with a\nY-junction created by three static sources are also reviewed. It is shown that\nstring spectra from lattice simulations are consistent with universal\npredictions of the leading operators from the derivative expansion of a\nPoincare invariant effective string Lagrangian with reparameterization\nsymmetry. Important characterisitics of the confining flux, like stiffness and\nthe related massive breather modes, are coded in operators with higher\nderivatives and their determination remains a difficult challenge for lattice\ngauge theory.",
        "positive": "Universality and the QCD Anderson Transition: We study the Anderson-type transition previously found in the spectrum of the\nQCD quark Dirac operator in the high temperature, quark-gluon plasma phase.\nUsing finite size scaling for the unfolded level spacing distribution, we show\nthat in the thermodynamic limit there is a genuine mobility edge, where the\nspectral statistics changes from Poisson to Wigner-Dyson statistics in a\nnon-analytic way. We determine the correlation length critical exponent, $\\nu$,\nand find that it is compatible with that of the unitary Anderson model."
    },
    {
        "anchor": "Introductory lectures on lattice QCD at nonzero baryon number: These lecture notes contain an elementary introduction to lattice QCD at\nnonzero chemical potential. Topics discussed include chemical potential in the\ncontinuum and on the lattice; the sign, overlap and Silver Blaze problems; the\nphase boundary at small chemical potential; imaginary chemical potential; and\ncomplex Langevin dynamics. An incomplete overview of other approaches is\npresented as well. These lectures are meant for postgraduate students and\npostdocs with an interest in extreme QCD. A basic knowledge of lattice QCD is\nassumed but not essential. Some exercises are included at the end.",
        "positive": "Strong Coupling Model for String Breaking on the Lattice: A model for SU(n) string breaking on the lattice is formulated using strong\ncoupling ideas. Although necessarily rather crude, the model gives an explicit\npicture of string breaking in the presence of dynamical quarks as a mixing\nphenomenon that involves the string state and a two-meson state. A careful\nanalysis, within the model, of the Wilson loop shows that the evolution of the\nmixing angle as a function of separation may obscure the expected crossover\neffect. If a sufficiently extensive mixing region exists then an appropriate\ncombination of transition amplitudes can help in revealing the effect.\n  The sensitivity of the mixing region to the values of the meson energy and\nthe dynamical quark mass is explored and an assessment made of the\ndectectibility of string breaking in a practical lattice simulation."
    },
    {
        "anchor": "Numerical Evidence for the Observation of a Scalar Glueball: We compute from lattice QCD in the valence (quenched) approximation the\npartial decay widths of the lightest scalar glueball to pairs of pseudoscalar\nquark-antiquark states. These predictions and values obtained earlier for the\nscalar glueball's mass are in good agreement with the observed properties of\n$f_J(1710)$ and inconsistent with all other observed meson resonances.",
        "positive": "Strongly and slightly flavored gauge theories: We review some recent progress in our understanding of the phase diagram of\nnon abelian gauge theories, by varying their flavor content -- fermion\nrepresentations and the number of flavors. In particular, we explore the way\nconformal symmetry can be restored before the loss of asymptotic freedom, and\nthrough a subtle interplay of perturbation theory, chiral dynamics and\nconfining forces. It is with the combination of numerical lattice studies and\ntheoretical insights into gauge theories with and without supersymmetry that we\nmay successfully attempt to clarify the missing pieces of this puzzle."
    },
    {
        "anchor": "PACS-CS results for 2+1 flavor lattice QCD simulation on and off the\n  physical point: We report on the PACS-CS project focusing on a direct simulation of 2+1\nflavor QCD on the physical point and chiral analysis of meson and baryon masses\noff the physical point with both the SU(2) and SU(3) chiral perturbation\ntheories. Configurations are generated with the O(a)-improved Wilson quark\naction and the Iwasaki gauge action. The up-down quark is simulated by\nemploying the DDHMC algorithm with several improvements and the UV-filtered\nPHMC algorithm is implemented for the strange quark. We investigate the\nconvergence behaviors of the SU(2) and SU(3) chiral expansions up to NLO for\nthe pseudoscalar meson sector, where the up-down quark mass ranges from 3 MeV\nto 24 MeV and the strange quark mass is chosen around the physical value. The\nfit results for the low energy constants are compared with those recently\nobtained by other groups. We also discuss the importance of the direct\nsimulation at the physical point by comparing the physical quantities measured\non the physical point with those estimated by the extrapolation method.",
        "positive": "Ab initio calculation of the neutron-proton mass difference: The existence and stability of atoms rely on the fact that neutrons are more\nmassive than protons. The measured mass difference is only 0.14\\% of the\naverage of the two masses. A slightly smaller or larger value would have led to\na dramatically different universe. Here, we show that this difference results\nfrom the competition between electromagnetic and mass isospin breaking effects.\nWe performed lattice quantum-chromodynamics and quantum-electrodynamics\ncomputations with four nondegenerate Wilson fermion flavors and computed the\nneutron-proton mass-splitting with an accuracy of $300$ kilo-electron volts,\nwhich is greater than $0$ by $5$ standard deviations. We also determine the\nsplittings in the $\\Sigma$, $\\Xi$, $D$ and $\\Xi_{cc}$ isospin multiplets,\nexceeding in some cases the precision of experimental measurements."
    },
    {
        "anchor": "Instantons from over-improved cooling: Lattice artefacts are used, through modified lattice actions, as a tool to\nfind the largest instantons in a toroidal geometry [0,L]^3X[0,T] for T to\ninfinity. It is conjectured that the largest instanton is associated with\ntunnelling through a sphaleron. Existence of instantons with at least 8\nparameters can be proven with the help of twisted boundary conditions in the\ntime direction. Numerical results for SU(2) gauge theory obtained by cooling\nare presented to demonstrate the viability of the method.",
        "positive": "B Mixing in the Standard Model and Beyond: Lattice QCD: We give a brief overview and progress report on our lattice QCD calculation\nof neutral B mixing hadronic matrix elements needed for Standard Model and\nBeyond the Standard Model physics. Reference [1] contains more details and\nresults."
    },
    {
        "anchor": "Lattice QCD Study for Confinement and Hadrons: Using SU(3) lattice QCD, we perform the detailed studies of the three-quark\nand the multi-quark potentials. From the accurate calculation for more than 300\ndifferent patterns of 3Q systems, the static ground-state 3Q potential $V_{\\rm\n3Q}^{\\rm g.s.}$ is found to be well described by the Coulomb plus Y-type linear\npotential (Y-Ansatz) within 1%-level deviation. As a clear evidence for\nY-Ansatz, Y-type flux-tube formation is actually observed on the lattice in\nmaximally-Abelian projected QCD. For about 100 patterns of 3Q systems, we\nperform the accurate calculation for the 1st excited-state 3Q potential $V_{\\rm\n3Q}^{\\rm e.s.}$ by diagonalizing the QCD Hamiltonian in the presence of three\nquarks, and find a large gluonic-excitation energy $\\Delta E_{\\rm 3Q} \\equiv\nV_{\\rm 3Q}^{\\rm e.s.}-V_{\\rm 3Q}^{\\rm g.s.}$ of about 1 GeV, which gives a\nphysical reason of the success of the quark model. $\\Delta E_{\\rm 3Q}$ is found\nto be reproduced by the ``inverse Mercedes Ansatz'', which indicates a\ncomplicated bulk excitation for the gluonic-excitation mode. We study also the\ntetra-quark and the penta-quark potentials in lattice QCD, and find that they\nare well described by the OGE Coulomb plus multi-Y type linear potential, which\nsupports the flux-tube picture even for the multi-quarks.",
        "positive": "QCD at non-zero temperature and magnetic field: A status of lattice QCD thermodynamics, as of 2013, is summarized. Only bulk\nthermodynamics is considered. There is a separate section on magnetic fields."
    },
    {
        "anchor": "Sharing lattices throughout the world: an ILDG status report: The international lattice data grid, a system for sharing gauge configuration\nfiles throughout the world, is operational for the most part. I give a status\nreport, give some pointers on accessing lattice files, and highlight some of\nthe available gauge configurations.",
        "positive": "Continuum Results for Light Hadronic Quantities using Domain Wall\n  Fermions with the Iwasaki and DSDR Gauge Actions: We present preliminary continuum results for light hadronic quantities\nobtained by the RBC/UKQCD collaboration using domain wall fermions with both\nthe Iwasaki and the novel Dislocation Suppressing Determinant Ratio (DSDR)\ngauge actions. The DSDR action allows us to simulate at near physical quark\nmasses on a larger, coarser lattice (a^-1 = 1.4 GeV, L = 4.6 fm) while\nretaining good chiral symmetry properties. We discuss our ongoing combined\nanalysis of the three ensemble sets and give early results for the pion and\nkaon decay constants, quark masses and B_K."
    },
    {
        "anchor": "Renormalization of a Contact Interaction on a Lattice: Contact interactions can be used to describe a system of particles at\nunitarity, contribute to the leading part of nuclear interactions and are\nnumerically non-trivial because they require a proper regularization and\nrenormalization scheme. We explain how to tune the coefficient of a contact\ninteraction between non-relativistic particles on a discretized space in 1, 2,\nand 3 spatial dimensions such that we can remove all discretization artifacts.\nBy taking advantage of a latticized L\\\"uscher zeta function, we can achieve a\nmomentum-independent scattering amplitude at any finite lattice spacing.",
        "positive": "A positivity property of the dimer entropy of graphs: The entropy of a monomer-dimer system on an infinite bipartite lattice can be\nwritten as a mean-field part plus a series expansion in the dimer density. In a\nprevious paper it has been conjectured that all coefficients of this series are\npositive. Analogously on a connected regular graph with $v$ vertices, the\n\"entropy\" of the graph ${\\rm ln} N(i)/v$, where $N(i)$ is the number of ways of\nsetting down $i$ dimers on the graph, can be written as a part depending only\non the number of the dimer configurations over the completed graph plus a\nNewton series in the dimer density on the graph. In this paper, we investigate\nfor which connected regular graphs all the coefficients of the Newton series\nare positive (for short, these graphs will be called positive). In the class of\nconnected regular bipartite graphs, up to $v=20$, the only non positive graphs\nhave vertices of degree $3$. From $v=14$ to $v=30$, the frequency of the\npositivity violations in the $3$-regular graphs decreases with increasing $v$.\nIn the case of connected $4$-regular bipartite graphs, the first violations\noccur in two out of the $2806490$ graphs with $v=22$. We conjecture that for\neach degree $r$ the frequency of the violations, in the class of the\n$r-$regular bipartite graphs, goes to zero as $v$ tends to infinity. This\ngraph-positivity property can be extended to non-regular or non-bipartite\ngraphs. We have examined a large number of rectangular grids of size $N_x\n\\times N_y $ both with open and periodic boundary conditions. We have observed\npositivity violations only for $min(N_x, N_y) = 3$ or $4$."
    },
    {
        "anchor": "2+1 flavor light hadron spectrum and quark masses with the O(a) improved\n  Wilson-clover quark formalism: We present a summary of results of the joint CP-PACS and JLQCD project toward\na 2+1 flavor full QCD simulation with the O(a)-improved Wilson quark formalism\nand the Iwasaki gauge action. Configurations were generated during 2002-2005 at\nthree lattice spacings, a~0.076, 0.100 and 0.122 fm, keeping the physical\nvolume constant at (2.0fm)^3. Up and down quark masses are taken in the range\nm_{PS}/m_V~0.6-0.78. We have completed the analysis for the light meson\nspectrum and quark masses in the continuum limit using the full configuration\nset. The predicted meson masses reproduce experimental values in the continuum\nlimit at a 1% level. The average up and down, and strange quark masses turn out\nto be m_{ud}^{\\bar{MS}}(\\mu=2 GeV)=3.50(14)({}^{+26}_{-15}) MeV and\nm_s^{\\bar{MS}}(\\mu=2 GeV)=91.8(3.9)({}^{+6.8}_{-4.1}) MeV. We discuss our\nfuture strategy toward definitive results on hadron spectroscopy with the\nWilson-clover formalism.",
        "positive": "Robustness of Gauge Digitization to Quantum Noise: Quantum noise limits the use of quantum memory in high energy physics\nsimulations. In particular, it breaks the gauge symmetry of stored quantum\nstates. We examine this effect for abelian and nonabelian theories and\ndemonstrate that optimizing the digitization of gauge theories to quantum\nmemory to account for noise channels can extend the lifetime before complete\nloss of gauge symmetry by $2-10\\times$ over some other digitizations. These\nconstructions also allow for quantum error correction to integrate the\nsymmetries of quantum fields and prioritize the largest gauge violations."
    },
    {
        "anchor": "Visualizations of the QCD Vacuum: Action and topological charge densities of the Euclidean-space QCD vacuum are\nvisualized in three-dimensional slices of a 24^3 x 36 space-time lattice and an\norder-a^2 improved 16^3 x 32 lattice. Features include instanton anti-instanton\nannihilation and a comparison of standard and over-improved actions used in the\nsmoothing of the gauge fields.",
        "positive": "Lattice calculation of the QGP viscosities - Present results and next\n  project -: The shear and bulk viscosities of gluon plasma are calculated by accumulating\na large amount of data for the Matsubara Green function ($G_{\\beta}(t_m)$) on\nisotropic $24^3 \\times 8$ and $16^3 \\times 8$ lattices. In the case of\nIwasaki's improved action, the calculations of $G_{\\beta}(t_m)$ are carried out\non roughly 6 million configurations, while for the standard action the\ncalculations are done on more than 16 million configurations. The shear\nviscosities increase roughly with $T^3$, and $\\eta/s$ ratios are close to the\nKSS lower bound in the region where $1<T/T_c<25$. Using these data the bulk\nviscosities are also determined in the region where $T/T_c < 2$. They are\nroughly one order of magnitude smaller than the shear viscosities. Our next\ntarget is to determine the transport coefficients more precisely by a\nmaximum-entropy method. For this purpose the most effective method may be to\nadopt an anisotropic lattice. In this report, we study the possible systematic\nerror due to the deformation of the anisotropic lattice at short distances.\nNear the critical temperature, it is found that the standard action suffers\nfrom a large deformation on the anisotropic lattice at short distances, while\nthe deformation is slight for Iwasaki's improved action. To reduce the\nfluctuation of the Matsubara Green function, the improvement of the energy\nmomentum tensor operator by using clover-type loops is promising. We are also\nattempting to apply the multi-level algorithm to reduce fluctuation."
    },
    {
        "anchor": "Analysis of the Lee-Yang zeros in a dynamical mass generation model in\n  three dimensions: We investigate a strongly U(1) gauge theory with fermions and scalars on a\nthree dimensional lattice and analyze whether the cintinuum limit might be a\nrenormalizable theory with dynamical mass generation. Most attention is paid to\nthe weak coupling region where a possible new dynamical mass generation\nmechanism might exist. There we investigate the mass of the composite fermion,\nthe chiral condensate and the scaling of the Lee-Yang zeros.",
        "positive": "Computation of the Kugo-Ojima function from lattice simulations: In addition to its connection with a standard confinement criterion, the\nKugo-Ojima function constitutes an indispensable component in a multitude of\napplications in the gauge sector of QCD. In the present work we report on\npreliminary results of an ongoing large-volume lattice simulation of this\nspecial function. In particular, the volume-dependence of the data is studied\nin detail, and a comparison with results obtained from Schwinger-Dyson\nequations is carried out."
    },
    {
        "anchor": "Short-distance matrix elements for $D^0$-meson mixing for $N_f=2+1$\n  lattice QCD: We calculate in three-flavor lattice QCD the short-distance hadronic matrix\nelements of all five $\\Delta C=2$ four-fermion operators that contribute to\nneutral $D$-meson mixing both in and beyond the Standard Model. We use the MILC\nCollaboration's $N_f = 2+1$ lattice gauge-field configurations generated with\nasqtad-improved staggered sea quarks. We also employ the asqtad action for the\nvalence light quarks and use the clover action with the Fermilab interpretation\nfor the charm quark. We analyze a large set of ensembles with pions as light as\n$M_\\pi \\approx 180$ MeV and lattice spacings as fine as $a\\approx 0.045$ fm,\nthereby enabling good control over the extrapolation to the physical pion mass\nand continuum limit. We obtain for the matrix elements in the\n$\\overline{\\text{MS}}$-NDR scheme using the choice of evanescent operators\nproposed by Beneke \\emph{et al.}, evaluated at 3 GeV, $\\langle\nD^0|\\mathcal{O}_i|\\bar{D}^0 \\rangle = \\{0.0805(55)(16), -0.1561(70)(31),\n0.0464(31)(9), 0.2747(129)(55), 0.1035(71)(21)\\}~\\text{GeV}^4$ ($i=1$--5). The\nerrors shown are from statistics and lattice systematics, and the omission of\ncharmed sea quarks, respectively. To illustrate the utility of our\nmatrix-element results, we place bounds on the scale of CP-violating new\nphysics in $D^0$~mixing, finding lower limits of about 10--50$\\times 10^3$ TeV\nfor couplings of $\\mathrm{O}(1)$. To enable our results to be employed in more\nsophisticated or model-specific phenomenological studies, we provide the\ncorrelations among our matrix-element results. For convenience, we also present\nnumerical results in the other commonly-used scheme of Buras, Misiak, and\nUrban.",
        "positive": "Infrared Propagators in MAG and Feynman gauge on the lattice: We propose to investigate infrared properties of gluon and ghost propagators\nrelated to the so-called Gribov-Zwanziger confinement scenario, originally\nformulated for Landau and Coulomb gauges, for other gauges as well. We present\nresults of our investigation of SU(2) lattice gauge theory in the maximally\nAbelian gauge (MAG), focusing on the behavior of propagators in the\noff-diagonal (i.e. non-Abelian) sector. We also comment on our preliminary\nresults for general linear covariant gauges, in particular for Feynman gauge."
    },
    {
        "anchor": "Quark-gluon vertex in arbitrary kinematics: We compute the quark-gluon vertex in quenched lattice QCD, in the Landau\ngauge using an off-shell mean-field O(a)-improved fermion action. The complete\nvertex is computed in two specific kinematical limits, while the Dirac-vector\npart is computed for arbitrary kinematics. We find a nontrivial and rich tensor\nstructure, including a substantial infrared enhancement of the interaction\nstrength regardless of kinematics.",
        "positive": "Debye mass from domainwalls and dimensionally reduced phase diagram: To measure the Debye mass in dimensionally reduced QCD for $N_c\\le 3$ we\nreplace in the correlator of two Polyakov loops one of the loops by a wall\ntriggered by a dimensionally reduced twist. The phase diagram for $N_c=3$ has\nR-parity broken in part of the Higgs phase."
    },
    {
        "anchor": "Generalization capabilities of neural networks in lattice applications: In recent years, the use of machine learning has become increasingly popular\nin the context of lattice field theories. An essential element of such theories\nis represented by symmetries, whose inclusion in the neural network properties\ncan lead to high reward in terms of performance and generalizability. A\nfundamental symmetry that usually characterizes physical systems on a lattice\nwith periodic boundary conditions is equivariance under spacetime translations.\nHere we investigate the advantages of adopting translationally equivariant\nneural networks in favor of non-equivariant ones. The system we consider is a\ncomplex scalar field with quartic interaction on a two-dimensional lattice in\nthe flux representation, on which the networks carry out various regression and\nclassification tasks. Promising equivariant and non-equivariant architectures\nare identified with a systematic search. We demonstrate that in most of these\ntasks our best equivariant architectures can perform and generalize\nsignificantly better than their non-equivariant counterparts, which applies not\nonly to physical parameters beyond those represented in the training set, but\nalso to different lattice sizes.",
        "positive": "Generalized Hyper-Systolic Algorithm: We generalize the hyper-systolic algorithm proposed in [1] for abstract data\nstructures on massive parallel computers with $n_p$ processors. For a problem\nof size $V$ the communication complexity of the hyper-systolic algorithm is\nproportional to $\\sqrt{n_p}V$, to be compared with $n_pV$ for the systolic\ncase. The implementation technique is explained in detail and the example of\nthe parallel matrix-matrix multiplication is tested on the Cray-T3D."
    },
    {
        "anchor": "The charm-quark contribution to light-by-light scattering in the muon\n  $(g-2)$ from lattice QCD: We compute the hadronic light-by-light scattering contribution to the muon\n$g-2$ from the charm quark using lattice QCD. The calculation is performed on\nensembles generated with dynamical $(u,d,s)$ quarks at the SU(3)$_{\\rm f}$\nsymmetric point with degenerate pion and kaon masses of around 415 MeV. It\nincludes the connected charm contribution, as well as the leading disconnected\nWick contraction, involving the correlation between a charm and a light-quark\nloop. Cutoff effects turn out to be sizeable, which leads us to use\nlighter-than-physical charm masses, to employ a broad range of lattice spacings\nreaching down to 0.039 fm and to perform a combined charm-mass and continuum\nextrapolation. We use the $\\eta_c$ meson to define the physical charm-mass\npoint and obtain a final value of $a_\\mu^{\\rm HLbL,c} = (2.8\\pm 0.5) \\times\n10^{-11}$, whose uncertainty is dominated by the systematics of the\nextrapolation. Our result is consistent with the estimate based on a simple\ncharm-quark loop, whilst being free of any perturbative scheme dependence on\nthe charm mass. The mixed charm-light disconnected contraction contributes a\nsmall negative amount to the final value.",
        "positive": "A New Way to Set the Energy Scale in Lattice Gauge Theories and its\n  Application to the Static Force and $\u03b1_s$ in SU(2) Yang--Mills Theory: We introduce a hadronic scale $R_0$ through the force $F(r)$ between static\nquarks at intermediate distances $r$. The definition $F(R_0)R_0^2=1.65$ amounts\nto $R_0 \\simeq 0.5$~fm in phenomenological potential models. Since $R_0$ is\nwell defined and can be calculated accurately in a Monte Carlo simulation, it\nis an ideal quantity to set the scale. In SU(2) pure gauge theory, we use new\ndata (and $R_0$ to set the scale) to extrapolate $F(r)$ to the continuum limit\nfor distances $r=0.18$~fm to $r=1.1$~fm. Through $R_0$ we determine the energy\nscale in the recently calculated running coupling, which used the recursive\nfinite size technique to reach large energy scales. Also in this case, the\nlattice data can be extrapolated to the continuum limit. The use of one loop\nSymanzik improvement is seen to reduce the lattice spacing dependence\nsignificantly.\n  Warning: The preprint is not completely fresh, but maybe you haven't seen\nit..."
    },
    {
        "anchor": "Toward the spectrum of the SU(2) adjoint Higgs model: Scalar particles in the adjoint representation of a non-Abelian gauge theory\nplay an important role in many scenarios beyond the standard model, especially\nof GUT type. For such theories manifestly gauge-invariant, massless, composite\nvector particles have been predicted, even at weak coupling, using the\nFr\\\"ohlich-Morchio-Strocchi mechanism. We use lattice gauge theory to\ninvestigate the simplest such theories, a single adjoint scalar coupled to an\nSU(2) Yang-Mills theory. The results support the existence of such a particle,\nin accordance with the prediction.",
        "positive": "Perturbative renormalization in parton distribution functions using\n  improved actions: We calculate the 1-loop renormalization of a set of extended fermionic\nbilinears which form a basis corresponding to moments of the parton\ndistribution functions.\n  We use the overlap action for fermions and Luescher-Weisz (LW) action for\ngluons.\n  Our results are presented as a function of the overlap parameter rho and the\nparameters entering the LW action."
    },
    {
        "anchor": "Heavy-light and light-light weak matrix elements on the lattice: I review recent developments in lattice weak matrix element calculations. I\nfocus on on $f_B$ (both with propagating quarks and in the static limit for the\n$b$ quark), semi-leptonic form factors for $D$ meson decay, form factors for $B\n\\to K^* \\gamma$, and $B_K$. [Review presented at Lattice '93]",
        "positive": "On the definition of schemes for computing leading order isospin\n  breaking corrections: We discuss an alternate scheme, or a 'line of constant physics', which can be\nused when computing isospin breaking corrections to hadronic quantities. We\nshow that within a certain class of schemes one can separate the\nelectromagnetic corrections from the strong isospin breaking corrections at\nleading order, meaning that within this class scheme-ambiguities are higher\norder effects."
    },
    {
        "anchor": "Fermionic Symmetry in Ichimatsu-Decomposed Lattice Models: We present the lattice models with exact fermionic symmetries relating\nfermions and link variables. The plaquettes are distributed in an Ichimatsu\npattern (chequered). We explain this peculiar structure allows us to have a\ntranslation in the algebra of the fermionic symmetries.",
        "positive": "The sign problem and the Lefschetz thimble: Recently, we have proposed a novel approach (arxiv:1205.3996) to deal with\nthe sign problem that hinders Monte Carlo simulations of many quantum field\ntheories (QFTs). The approach consists in formulating the QFT on a Lefschetz\nthimble. In this paper we concentrate on the application to a scalar field\ntheory with a sign problem. In particular, we review the formulation and the\njustification of the approach, and we also describe the Aurora Monte Carlo\nalgorithm that we are currently testing."
    },
    {
        "anchor": "Landau Ginzberg model and deconfinement transition for extended SU(2)\n  action: We compute the effective action in terms of the Polyakov loop for the\n3-dimensional pure fundamental-adjoint SU(2) lattice gauge theory at non-zero\ntemperatures using the strong coupling expansion. In the extended coupling\nplane we show the existence of a tricritical point where the nature of the\ndeconfinement transition undergoes a change from second to first order. The\nresulting phase structure is in excellent agreement with the Monte Carlo\nresults both in the fundamental and adjoint directions. The possible\nconsequences of our results on universality are discussed.",
        "positive": "Lattice QCD calculation of the invisible decay $J/\u03c8\\rightarrow\n  \u03b3\u03bd\\bar\u03bd$: In this work, we present the first lattice QCD study on the invisible decay\n$J/\\psi \\rightarrow \\gamma\\nu\\bar{\\nu}$. The calculation is accomplished using\n$N_f=2$ twisted mass fermion ensembles. The excited-state effects are observed\nand eliminated using a multi-state fit. The impact of finite-volume effects is\nalso examined and confirmed to be well-controlled. After a continuous\nextrapolation under three lattice spacings, we obtain the branching fraction as\n$\\operatorname{Br}[J/\\psi \\rightarrow \\gamma\\nu\\bar{\\nu}]=1.00(9)(7)\\times\n10^{-10}$, where the first error is the statistical error and the second is an\nestimate of the systematics. The exact theoretical prediction can be used to\nremove the only invisible contamination from the standard model background in\nsearching for the possible dark matter by the channel $J/\\psi \\rightarrow\n\\gamma+\\textrm{invisible}$"
    },
    {
        "anchor": "Improved Lattice Gauge Field Hamiltonian: Lepage's improvement scheme is a recent major progress in lattice $QCD$,\nallowing to obtain continuum physics on very coarse lattices. Here we discuss\nimprovement in the Hamiltonian formulation, and we derive an improved\nHamiltonian from a lattice Lagrangian free of $O(a^2)$ errors. We do this by\nthe transfer matrix method, but we also show that the alternative via Legendre\ntransformation gives identical results. We consider classical improvement,\ntadpole improvement and also the structure of L{\\\"u}scher-Weisz improvement.\nThe resulting color-electric energy is an infinite series, which is expected to\nbe rapidly convergent. For the purpose of practical calculations, we construct\na simpler improved Hamiltonian, which includes only nearest-neighbor\ninteractions.",
        "positive": "Effect of low-lying fermion modes in the $\u03b5$-regime of QCD: We investigate the effects of low-lying fermion eigenmodes on the QCD\npartition function in the $\\epsilon$-regime. The fermion determinant is\napproximated by a truncated product of low-lying eigenvalues of the\noverlap-Dirac operator. With two flavors of dynamical quarks, we observe that\nthe lattice results for the lowest eigenvalue distribution, eigenvalue sum\nrules and partition function reproduce the analytic predictions made by\nLeutwyler and Smilga, which strongly depend on the topological charge of the\nbackground gauge configuration. The value of chiral condensate extracted from\nthese measurements are consistent with each other. For one dynamical quark\nflavor, on the other hand, we find an apparent disagreement among different\ndeterminations of the chiral condensate, which may suggest the failure of the\n$\\epsilon$-expansion in the absence of massless Nambu-Goldstone boson."
    },
    {
        "anchor": "Monte Carlo Simulation of a NC Gauge Theory on The Fuzzy Sphere: We find using Monte Carlo simulation the phase structure of noncommutative\nU(1) gauge theory in two dimensions with the fuzzy sphere S^2_N as a\nnon-perturbative regulator. There are three phases of the model. i) A matrix\nphase where the theory is essentially SU(N) Yang-Mills reduced to zero\ndimension . ii) A weak coupling fuzzy sphere phase with constant specific heat\nand iii) A strong coupling fuzzy sphere phase with non-constant specific heat.\nThe order parameter distinguishing the matrix phase from the sphere phase is\nthe radius of the fuzzy sphere. The three phases meet at a triple point. We\nalso give the theoretical one-loop and 1/N expansion predictions for the\ntransition lines which are in good agreement with the numerical data. A Monte\nCarlo measurement of the triple point is also given.",
        "positive": "High precision study of B*B pi coupling in unquenched QCD: The B* B pi coupling is a fundamental parameter of chiral effective\nLagrangian with heavy-light mesons and can constrain the B->pi l nu form factor\nin the soft pion limit which will be useful for precise determination of |Vub|.\nWe compute the B* B pi coupling with the static heavy quark and the\nO(a)-improved Wilson light quark. Simulations are carried out with n_f=2\nunquenched 12^3x24 lattices at beta=1.80 generated by CP-PACS collaboration.\nFollowing the quenched study by Negishi et al., we employ the all-to-all\npropagator with 200 low eigenmodes as well as HYP smeared link to improve the\nstatistical accuracy."
    },
    {
        "anchor": "A comprehensive picture of topological excitations in finite temperature\n  lattice QCD: We study spectra, localization properties and local chirality of eigenvectors\nof the lattice Dirac operator. We analyze ensembles of quenched SU(3)\nconfigurations on both sides of the QCD phase transition. Our Dirac operator is\na systematic expansion in path length of a solution of the Ginsparg-Wilson\nequation. Analyzing the finite volume behavior of our observables and their\nscaling with the gauge coupling we come up with a consistent picture of\ntopological excitations on both sides of the QCD phase transition. Our results\nsupport the interpretation of the dominant gauge field excitations seen by the\nDirac operator as a fluid of instanton-like objects.",
        "positive": "The Kaon B-parameter in Mixed Action Chiral Perturbation Theory: We calculate the kaon B-parameter, B_K, in chiral perturbation theory for a\npartially quenched, mixed action theory with Ginsparg-Wilson valence quarks and\nstaggered sea quarks. We find that the resulting expression is similar to that\nin the continuum, and in fact has only two additional unknown parameters. At\none-loop order, taste-symmetry violations in the staggered sea sector only\ncontribute to flavor-disconnected diagrams by generating an O(a^2) shift to the\nmasses of taste-singlet sea-sea mesons. Lattice discretization errors also give\nrise to an analytic term which shifts the tree-level value of B_K by an amount\nof O(a^2). This term, however, is not strictly due to taste-breaking, and is\ntherefore also present in the expression for B_K for pure G-W lattice fermions.\nWe also present a numerical study of the mixed B_K expression in order to\ndemonstrate that both discretization errors and finite volume effects are small\nand under control on the MILC improved staggered lattices."
    },
    {
        "anchor": "Orthogonal Technicolor with Isotriplet Dark Matter on the Lattice: We study the gauge dynamics of an SO(4)-gauge theory with two Dirac Wilson\nfermions transforming according to the vector representation of the gauge\ngroup. We determine the lattice phase diagram by locating the strong coupling\nbulk phase transition line and the zero PCAC mass line. We present results for\nthe spectrum of the theory. In particular we measure the pseudoscalar, vector\nand axial meson masses. The data are consistent with a chiral symmetry breaking\nscenario rather than a conformal one. When used to break the electroweak\nsymmetry dynamically the model leads to a natural dark matter candidate.",
        "positive": "Asymptotic Scaling and Monte Carlo Data: It is a generally known problem that the behaviour predicted from\nperturbation theory for asymptotically free theories like QCD, i.e. asymptotic\nscaling, has not been observed in Monte Carlo simulations when the series is\nexpressed in terms of the bare coupling g_0. This discrepancy has been\nexplained in the past with the poor convergence properties of the perturbative\nseries in the g_0. An alternative point of view, called Lattice-Distorted\nPerturbation Theory proposes that lattice artifacts due to the finiteness of\nthe lattice spacing, a, cause the disagreement between Monte Carlo data and\nperturbative scaling. Following this alternative scenario, we fit recent\nquenched data from different observables to fitting functions that include\nthese cut-off effects, confirming that the lattice data are well reproduced by\ng_0-PT with the simple addition of terms O(a^n)."
    },
    {
        "anchor": "Spontaneous supersymmetry breaking in the 2d N=1 Wess-Zumino model: We study the phase diagram of the two-dimensional N=1 Wess-Zumino model using\nWilson fermions and the fermion loop formulation. We give a complete\nnon-perturbative determination of the ground state structure in the continuum\nand infinite volume limit. We also present a determination of the particle\nspectrum in the supersymmetric phase, in the supersymmetry broken phase and\nacross the supersymmetry breaking phase transition. In the supersymmetry broken\nphase we observe the emergence of the Goldstino particle.",
        "positive": "Hamiltonian SU(N) Lattice Gauge Theories With Exact Vacuum States In 2+1\n  Dimensions: We investigate (2+1)-d Hamiltonian lattice gauge theory using a class of\nHamiltonians having exactly known vacuum states. These theories are shown to\nhave a wide range of possible classical continuum limits which differ from that\nof the standard Kogut-Susskind Hamiltonian. This conclusion is at variance with\nsome previously published results. We examine the quantum continuum behavior of\nthese theories by both analytic and numerical methods including plaquette space\nintegration and standard Monte Carlo techniques. String tension and variational\nestimates for the $J^{\\rm PC}=0^{++}$ glueball spectra are presented for SU(3).\nWe find that in spite of the wide range of classical behavior predicted, these\ntheories correspond to only two distinct quantum systems in the weak coupling\nlimit. One of these quantum limits gives string tensions and glueball states\nwhich show scaling in weak coupling which agrees with the perturbative\nprediction for the (2+1)-d problem."
    },
    {
        "anchor": "The three flavour chiral phase transition with an improved quark and\n  gluon action in lattice QCD: The finite-temperature chiral phase transition is investigated for three\nflavours of staggered quarks on a lattice of temporal extent N_t=4. In the\nsimulation we use an improved fermion action which reduces rotational symmetry\nbreaking of the quark propagator (p4-action), include fat-links to improve the\nflavour symmetry and use the tree level improved (1,2) gluon action. We study\nthe nature of the phase transition for quark masses of ma=0.025, ma=0.05 and\nma=0.1 on lattices with spatial sizes of 8^3 and 16^3.",
        "positive": "Gauge theories with overlap fermions in an arbitrary representation:\n  Evaluation of the 3-loop beta-function: This work presents the calculation of the relation between the bare coupling\nconstant g_0 and the MSbar-renormalized coupling g_MS, g_0 = Z_g(g_0,a\\mu)\ng_MS, to 2 loops in perturbation theory, with fermions in an arbitrary\nrepresentation of the gauge group SU(N). Our calculation is performed using\noverlap fermions and Wilson gluons, and the background field technique has been\nchosen for convenience. The corresponding results in the fundamental\nrepresentation appear in our longer publication [arXiv:0709.4368].\n  The 3-loop coefficient of the bare beta-function, b_2^L, is extracted using\nthe 2-loop expression for Z_g, and it is presented as a function of the overlap\nparameter rho, the number of fermion flavors (N_f) and the number of colors\n(N). We also provide the expression for the ratio Lambda_L/Lambda_MS, in an\narbitrary representation. A plot of Lambda_L/Lambda_MS is given in the adjoint\nrepresentation."
    },
    {
        "anchor": "A Study of the 't Hooft Model with the Overlap Dirac Operator: We present the results of an exploratory numerical study of two dimensional\nQCD with overlap fermions. We have performed extensive simulations for U(N_c)\nand SU(N_c) color groups with N_c=2, 3, 4 and coupling constants chosen to\nsatisfy the 't Hooft condition g^2 N_c =const=4/3. We have computed the meson\nspectrum and decay constants, the topological susceptibility and the chiral\ncondensate. For U(N_c) gauge groups, our results indicate that the\nWitten-Veneziano relation is satisfied within our statistical errors and that\nthe chiral condensate for N_f=1 is compatible with a non-zero value. Our\nresults exhibit universality in N_c and confirm once more the excellent chiral\nproperties of the overlap-Dirac operator.",
        "positive": "Colorful vortex intersections in SU(2) lattice gauge theory and their\n  influencs on chiral properties: We introduce topological non-trivial colorful regions around intersection\npoints of two perpendicular vortex pairs and investigate their influence on\ntopological charge density and eigenmodes of the Dirac operator. With\nincreasing distance between the vortices the eigenvalues of the lowest modes\ndecrease. We show that the maxima and minima of the chiral densities of the low\nmodes follow mainly the distributions of the topological charge densities. The\ntopological non-trivial color structures lead in some low modes to distinct\npeaks in the chiral densities. The other low modes reflect the topological\ncharge densities of the intersection points."
    },
    {
        "anchor": "Four-dimensional factorization of the fermion determinant in lattice QCD: In the last few years it has been proposed a one-dimensional factorization of\nthe fermion determinant in lattice QCD with Wilson-type fermions that leads to\na block-local action of the auxiliary bosonic fields. Here we propose a\nfour-dimensional generalization of this factorization. Possible applications\nare more efficient parallelizations of Monte Carlo algorithms and codes, master\nfield simulations, and multi-level integration.",
        "positive": "Baryon interactions in lattice QCD: the direct method vs. the HAL QCD\n  potential method: We make a detailed comparison between the direct method and the HAL QCD\npotential method for the baryon-baryon interactions, taking the $\\Xi\\Xi$ system\nat $m_\\pi= 0.51$ GeV in 2+1 flavor QCD and using both smeared and wall quark\nsources. The energy shift $\\Delta E_\\mathrm{eff}(t)$ in the direct method shows\nthe strong dependence on the choice of quark source operators, which means that\nthe results with either (or both) source are false. The time-dependent HAL QCD\nmethod, on the other hand, gives the quark source independent $\\Xi\\Xi$\npotential, thanks to the derivative expansion of the potential, which absorbs\nthe source dependence to the next leading order correction. The HAL QCD\npotential predicts the absence of the bound state in the $\\Xi\\Xi$($^1$S$_0$)\nchannel at $m_\\pi= 0.51$ GeV, which is also confirmed by the volume dependence\nof finite volume energy from the potential. We also demonstrate that the origin\nof the fake plateau in the effective energy shift $\\Delta E_\\mathrm{eff}(t)$ at\n$t \\sim 1$ fm can be clarified by a few low-lying eigenfunctions and\neigenvalues on the finite volume derived from the HAL QCD potential, which\nimplies that the ground state saturation of $\\Xi\\Xi$($^1$S$_0$) requires $t\n\\sim 10$ fm in the direct method for the smeared source on $(4.3 \\\n\\mathrm{fm})^3$ lattice, while the HAL QCD method does not suffer from such a\nproblem."
    },
    {
        "anchor": "On the Definition of the Partition Function in Quantum Regge Calculus: We argue that the definition of the partition function used recently to\ndemonstrate the failure of Regge calculus is wrong. In fact, in the\none-dimensional case, we show that there is a more natural definition, with\nwhich one can reproduce the correct results.",
        "positive": "On the nature of the residual meson-meson interaction from simulations\n  with a QED${}_{2+1}$ model: A potential between mesons is extracted from 4-point functions within lattice\ngauge theory taking 2+1 dimensional QED as an example. This theory possesses\nconfinement and dynamical fermions. The resulting meson-meson potential has a\nshort-ranged hard repulsive core and the expected dipole-dipole forces lead to\nattraction at intermediate distances. Sea quarks lead to a softer form of the\ntotal potential."
    },
    {
        "anchor": "Critical exponents of the three-dimensional classical plane rotator\n  model on the sc lattice from a high temperature series analysis: High temperature series expansions of the spin-spin correlation function for\nthe plane rotator (or XY) model on the sc lattice are extended by three terms\nthrough order $\\beta^{17}$. Tables of the expansion coefficients are reported\nfor the correlation function spherical moments of order $l=0,1,2$. Our analysis\nof the series leads to fairly accurate estimates of the critical parameters.",
        "positive": "Study of the axial U(1) anomaly at high temperature with lattice chiral\n  fermions: We investigate the axial U(1) anomaly of two-flavor QCD at temperatures\n190--330 MeV. In order to preserve precise chiral symmetry on the lattice, we\nemploy the Mobius domain-wall fermion action as well as overlap fermion action\nimplemented with a stochastic reweighting technique. Compared to our previous\nstudies, we reduce the lattice spacing to 0.07 fm, simulate larger multiple\nvolumes to estimate finite size effect, and take more than four quark mass\npoints, including one below physical point to investigate the chiral limit. We\nmeasure the topological susceptibility, axial U(1) susceptibility, and examine\nthe degeneracy of U(1) partners in meson and baryon correlators. All the data\nabove the critical temperature indicate that the axial U(1) violation is\nconsistent with zero within statistical errors. The quark mass dependence\nsuggests disappearance of the U(1) anomaly at a rate comparable to that of the\nSU(2)_L x SU(2)_R symmetry breaking."
    },
    {
        "anchor": "Comparison between models of QCD with and without dynamical charm quarks: We investigate the influence of dynamical charm quarks on observables that\ndepend explicitly on the charm quark fields, like the pseudo-scalar and vector\nmasses $m_{\\eta_c}$ and $m_{J/\\psi}$, the hyperfine splitting\n$(m_{J/\\psi}-m_{\\eta_c})/m_{\\eta_c}$, the charm quark mass and the meson decay\nconstants. For this purpose, instead of working in full QCD we study a\nsimplified setup. We simulate two theories: $N_f= 0$ QCD and QCD with $N_f= 2$\ndynamical quarks at the charm mass. The absence of light quarks allows us to\nreach extremely fine lattice spacings (0.02 fm < a < 0.05 fm) which are crucial\nfor reliable continuum extrapolations. Our main result is a comparison of\nvarious quantities in the continuum limit. For the hyperfine splitting we find\nthat the effects of a dynamical charm quark are below our statistical precision\nof $2\\%$.",
        "positive": "Investigating efficient methods for computing four-quark correlation\n  functions: We discuss and compare the efficiency of various methods, combinations of\npoint-to-all propagators, stochastic timeslice-to-all propagators, the one-end\ntrick and sequential propagators, to compute two-point correlation functions of\ntwo-quark and four-quark interpolating operators of different structure\nincluding quark-antiquark type, mesonic molecule type, diquark-antidiquark type\nand two-meson type. Although we illustrate our methods in the context of the\n$a_0(980)$, they can be applied for other multi-quark systems, where similar\ndiagrams appear. Thus our results could provide helpful guidelines on the\nchoice of methods for correlation function computation for future lattice QCD\nstudies of meson-meson scattering and possibly existing tetraquark states."
    },
    {
        "anchor": "Hybrid Monte Carlo and topological modes of full QCD: We investigate the performance of the hybrid Monte Carlo algorithm, the\nstandard algorithm used for lattice QCD simulations involving fermions, in\nupdating non-trivial global topological structures. We find that the hybrid\nMonte Carlo algorithm has serious problems decorrelating the global topological\ncharge at the values of $\\beta$ and $m$ currently simulated, where continuum\nphysics should be approximately realized. This represents a warning which must\nbe seriously considered when simulating full QCD by hybrid Monte Carlo.",
        "positive": "New proposal for numerical simulations of systems with a theta-vacuum\n  term: A new approach to perform numerical simulations of systems with a\ntheta-vacuum term is proposed, tested, and applied to CP3 The main new\ningredient of this approach is the method used to compute the probability\ndistribution function of the topological charge at theta=0. We comment also on\nthe possibility of applying this approach to QCD at finite baryon density."
    },
    {
        "anchor": "Walking and conformal dynamics in many-flavor QCD: In the search for a realistic walking technicolor model, QCD with many\nflavors is an attractive candidate. From the series of studies by the LatKMI\ncollaboration, we present updated results of the scaling properties of various\nhadron spectra, including the (pseudo)scalar, vector, and baryon channels, for\n$N_f=8$ QCD analyzed with the HISQ action. By comparing these with $N_f=12$\nQCD, which has properties consistent with conformality, possible signals of\nwalking dynamics are discussed. We also present a preliminary result of the\nflavor-singlet pseudoscalar mass in many-flavor QCD.",
        "positive": "Lattice calculations of Ds to eta and eta' decay form factors: We report on lattice results of the form factors for semi-leptonic decays of\nthe D_s meson to eta and eta', with n_f=2+1 configurations. The calculation\ncontains disconnected fermion loop diagrams, which are challenging to calculate\non the lattice. Our result shows that the disconnected diagrams give\nsignificant contributions to the form factors."
    },
    {
        "anchor": "Physical results from 2+1 flavor Domain Wall QCD: We review recent results for the chiral behavior of meson masses and decay\nconstants and the determination of the light quark masses by the RBC and UKQCD\ncollaborations. We find that one-loop SU(2) chiral perturbation theory\nrepresents the behavior of our lattice data better than one-loop SU(3) chiral\nperturbation theory in both the pion and kaon sectors.\n  The simulations have been performed using the Iwasaki gauge action at two\ndifferent lattice spacings with the physical spatial volume held approximately\nfixed at (2.7 fm)^3. The Domain Wall fermion formulation was used for the 2+1\ndynamical quark flavors: two (mass degenerate) light flavors with masses as\nlight as roughly 1/5 the mass of the physical strange quark mass and one\nheavier quark flavor at approximately the value of the physical strange quark\nmass.\n  On the ensembles generated with the coarser lattice spacing, we obtain for\nthe physical average up- and down-quark and strange quark masses\nm_ud(MSbar,2GeV)=3.72(0.16)_stat(0.33)_ren(0.18)_syst MeV and\nm_s(MSbar,2GeV)=107.3(4.4)_stat(9.7)_ren(4.9)_syst MeV, respectively, while we\nfind for the pion and kaon decay constants f_pi=124.1(3.6)_stat(6.9)_syst MeV,\nf_K=149.6(3.6)_stat(6.3)_syst MeV. The analysis for the finer lattice spacing\nhas not been fully completed yet, but we already present some first\n(preliminary) results.",
        "positive": "Gauge-independent Abelian mechanism of color confinement in gluodynamics: Abelian mechanism of non-Abelian color confinement is observed in a\ngauge-independent way by high precision lattice Monte Carlo simulations in\ngluodynamics. An Abelian gauge field is extracted with no gauge-fixing. A\nstatic quark-antiquark potential derived from Abelian Polyakov loop correlators\ngives us the same string tension as the non-Abelian one. The Hodge\ndecomposition of the Abelian Polyakov loop correlator to the regular photon and\nthe singular monopole parts also reveals that only the monopole part is\nresponsible for the string tension. The investigation of the flux-tube profile\nthen shows that Abelian electric fields defined in an arbitrary color direction\nare squeezed by monopole supercurrents with the same color direction, and the\nquantitative features of flux squeezing are consistent with those observed\npreviously after Abelian projections with gauge fixing. Gauge independence of\nAbelian and monopole dominance strongly supports that the mechanism of\nnon-Abelian color confinement is due to the Abelian dual Meissner effect."
    },
    {
        "anchor": "Simulation of Field Theories in Wavelet Representation: The field is expanded in a wavelet series and the wavelet coefficients are\nvaried in a simulation of the 2D $\\phi^4$ field theory. The drastically reduced\nautocorrelations result in a substantial decrease of computing requirements,\ncompared to those in local Metropolis simulations. A large part of the\nimprovement is shown to be the result of an additional freedom in the choice of\nthe allowed range of change at the Metropolis update of wavelet components,\nnamely the range can be optimized independently for all wavelet sizes.",
        "positive": "Absence of evidence for pentaquarks on the lattice: We study the question of whether or not QCD predicts a pentaquark state. We\nuse the improved, fixed point lattice QCD action which has very little\nsensitivity to the lattice spacing and also allows us to reach light quark\nmasses. The analysis was performed on a single volume of size $(1.8 {\\rm\nfm})^3\\times 3.6 {\\rm fm}$ with lattice spacing of $a=0.102$ fm. We use the\ncorrelation matrix method to identify the ground and excited states in the\nisospin 0, negative parity channel. In the quenched approximation where\ndynamical quark effects are omitted, we do not find any evidence for a\npentaquark resonance in QCD."
    },
    {
        "anchor": "Spectrum of SU(2) gauge theory with two fermions in the adjoint\n  representation: We present preliminary results of lattice simulations of SU(2) gauge theory\nwith two Wilson fermions in the adjoint representation. This theory has\nrecently attracted considerable attention because it might possess an infrared\nfixed point (or an almost-fixed-point), and hence be a candidate for a walking\ntechnicolor theory. In this work we study the particle spectrum of the theory,\nand compare it with more familiar spectrum of the theory with SU(2) gauge\nfields and two flavors of fundamental representation fermions.",
        "positive": "$\\mathcal{N}=1$ Supersymmetric $SU(3)$ Gauge Theory - Towards\n  simulations of Super-QCD: $\\mathcal{N}=1$ supersymmetric QCD (SQCD) is a possible building block of\ntheories beyond the standard model. It describes the interaction between gluons\nand quarks with their superpartners, gluinos and squarks. Since supersymmetry\nis explicitly broken by the lattice regularization, a careful fine-tuning of\noperators is necessary to obtain a supersymmetric continuum limit. For the pure\ngauge sector, $\\mathcal{N}=1$ Supersymmetric Yang-Mills theory, supersymmetry\nis only broken by a non-vanishing gluino mass. If we add matter fields, this is\nno longer true and more operators in the scalar squark sector have to be\nconsidered for fine-tuning the theory. Guided by a one-loop calculation in\nlattice perturbation theory, we show that maintaining chiral symmetry in the\nlight sector is nevertheless an important step. Furthermore, we present first\npreliminary lattice results on the fine-tuning and Ward-identities of SQCD."
    },
    {
        "anchor": "Curvature of the pseudocritical line in QCD: Taylor expansion matches\n  analytic continuation: We determine the curvature of the pseudo-critical line of $N_f = 2 + 1$ QCD\nwith physical quark masses via Taylor expansion in the quark chemical\npotentials. We adopt a discretization based on stout improved staggered\nfermions and the tree level Symanzik gauge action; the location of the\npseudocritical temperature is based on chiral symmetry restoration. Simulations\nare performed on lattices with different temporal extent ($N_t = 6, 8, 10$),\nleading to a continuum extrapolated curvature $\\kappa = 0.0145(25)$, which is\nin very good agreement with the continuum extrapolation obtained via analytic\ncontinuation and the same discretization, $\\kappa = 0.0135(20)$. This result\neliminates the possible tension emerging when comparing analytic continuation\nwith earlier results obtained via Taylor expansion.",
        "positive": "Dimensional reduction and confinement from five dimensions: We study non-perturbatively five-dimensional SU(2) gauge theories by means of\nthe mean-field expansion on the lattice. On the anisotropic torus we show that\na continuum limit can be defined where the anisotropy is a relevant parameter.\nThe analysis of the static force supports the fact that the four-dimensional\nhyperplanes decouple from each other in the continuum limit. Clear signs of\nconfinement are found in the static potential along the hyperplanes. We present\nfirst results from Monte Carlo simulations on the phase diagram."
    },
    {
        "anchor": "D to K and D to pi semileptonic form factors from Lattice QCD: We present a very high statistics study of D and D_s semileptonic decay form\nfactors on the lattice. We work with MILC N_f=2+1 lattices and use the Highly\nImproved Staggered Quark action (HISQ) for both the charm and the strange and\nlight valence quarks. We use both scalar and vector currents to determine the\nform factors f_0(q^2) and f_+(q^2) for a range of D and D_s semileptonic\ndecays, including D to pi and D to K. By using a phased boundary condition we\nare able to tune accurately to q^2=0 and explore the whole q^2 range allowed by\nkinematics. We can thus compare the shape in q^2 to that from experiment and\nextract the CKM matrix element |V_cs|. We show that the form factors are\ninsensitive to the spectator quark: D to K and D_s to eta_s form factors are\nessentially the same, which is also true for D to pi and D_s to K within 5%.\nThis has important implications when considering the corresponding B/B_s\nprocesses.",
        "positive": "Leveraging neural control variates for enhanced precision in lattice\n  field theory: Results obtained with stochastic methods have an inherent uncertainty due to\nthe finite number of samples that can be achieved in practice. In lattice QCD\nthis problem is particularly salient in some observables like, for instance,\nobservables involving one or more baryons and it is the main problem preventing\nthe calculation of nuclear forces from first principles. The method of control\nvariables has been used extensively in statistics and it amounts to computing\nthe expectation value of the difference between the observable of interest and\nanother observable whose average is known to be zero but is correlated with the\nobservable of interest. Recently, control variates methods emerged as a\npromising solution in the context of lattice field theories. In our current\nstudy, instead of relying on an educated guess to determine the control\nvariate, we utilize a neural network to parametrize this function. Using 1+1\ndimensional scalar field theory as a testbed, we demonstrate that this neural\nnetwork approach yields substantial improvements. Notably, our findings\nindicate that the neural network ansatz is particularly effective in the strong\ncoupling regime."
    },
    {
        "anchor": "Parity-expanded variational analysis for non-zero momentum: In recent years, the use of variational analysis techniques in lattice QCD\nhas been demonstrated to be successful in the investigation of the rest-mass\nspectrum of many hadrons. However, due to parity-mixing, more care must be\ntaken for investigations of boosted states to ensure that the projected\ncorrelation functions provided by the variational analysis correspond to the\nsame states at zero momentum. In this paper we present the Parity-Expanded\nVariational Analysis (PEVA) technique, a novel method for ensuring the\nsuccessful and consistent isolation of boosted baryons through a parity\nexpansion of the operator basis used to construct the correlation matrix.",
        "positive": "Comparison of algorithms for solving the sign problem in the O(3) model\n  in 1+1 dimensions at finite chemical potential: We study three possible ways to circumvent the sign problem in the O(3)\nnonlinear sigma model in 1+1 dimensions. We compare the results of the worm\nalgorithm to complex Langevin and multiparameter reweighting. Using the worm\nalgorithm, the thermodynamics of the model is investigated, and continuum\nresults are shown for the pressure at different $\\mu/T$ values in the range\n$0-4$. By performing $T=0$ simulations using the worm algorithm the Silver\nBlaze phenomenon is reproduced. Regarding the complex Langevin, we test various\nimplementations of discretizing the complex Langevin equation. We found that\nthe exponentialized Euler discretization of the Langevin equation gives wrong\nresults for the action and the density at low $T/m$. By performing continuum\nextrapolation we found that this discrepancy does not disappear and depends\nslightly on temperature. The discretization with spherical coordinates perform\nsimilarly at low $\\mu/T$, but goes wrong also at some higher temperatures at\nhigh $\\mu/T$. However, a third discretization that uses a constraining force to\nachieve the $\\phi^2 = 1$ condition gives correct results for the action, but\nwrong results for the density at low $\\mu/T$."
    },
    {
        "anchor": "Moments of Ioffe time parton distribution functions from non-local\n  matrix elements: We examine the relation of moments of parton distribution functions to matrix\nelements of non-local operators computed in lattice quantum chromodynamics. We\nargue that after the continuum limit is taken, these non-local matrix elements\ngive access to moments that are finite and can be matched to those defined in\nthe $\\overline{MS}$ scheme. We demonstrate this fact with a numerical\ncomputation of moments through non-local matrix elements in the quenched\napproximation and we find that these moments are in excellent agreement with\nthe moments obtained from direct computations of local twist-2 matrix elements\nin the quenched approximation.",
        "positive": "$B_c \\to B_{s(d)}$ form factors from lattice QCD: We present results of the first lattice QCD calculations of $B_c \\to B_s$ and\n$B_c \\to B_d$ weak matrix elements. Form factors across the entire physical\n$q^2$ range are then extracted and extrapolated to the physical-continuum limit\nbefore combining with CKM matrix elements to predict the semileptonic decay\nrates $\\Gamma(B_c^+ \\to B_s^0 \\overline{\\ell} \\nu_{\\ell}) = 26.2(1.2) \\times\n10^9 \\,\\text{s}^{-1}$ and $\\Gamma(B_c^+ \\to B^0 \\overline{\\ell} \\nu_{\\ell}) =\n1.65(10) \\times 10^9 \\,\\text{s}^{-1}$. The lattice QCD uncertainty is\ncomparable to the CKM uncertainty here. Results are derived from correlation\nfunctions computed on MILC Collaboration gauge configurations with a range of\nlattice spacings including 2+1+1 flavours of dynamical sea quarks in the Highly\nImproved Staggered Quark (HISQ) formalism. HISQ is also used for the\npropagators of the valence light, strange, and charm quarks. Two different\nformalisms are employed for the bottom quark: non-relativistic QCD (NRQCD) and\nheavy-HISQ. Checking agreement between these two approaches is an important\ntest of our strategies for heavy quarks on the lattice. From chained fits of\nNRQCD and heavy-HISQ data, we obtain the differential decay rates $d\\Gamma/ d\nq^2$ as well as integrated values for comparison to future experimental\nresults."
    },
    {
        "anchor": "History of Lattice Field Theory from a Statistical Perspective: Researchers working in lattice field theory constitute an established\ncommunity since the early 1990s, and around the same time the online\nopen-access e-print repository arXiv was created. The fact that this field has\na specific arXiv section, hep-lat, which is comprehensively used, provides a\nunique opportunity for a statistical study of its evolution over the last three\ndecades. We present data for the number of entries, $E$, published papers, $P$,\nand citations, $C$, in total and separated by nations. We compare them to six\nother arXiv sections (hep-ph, hep-th, gr-qc, nucl-th, quant-ph, cond-mat) and\nto two socio-economic indices of the nations involved: the Gross Domestic\nProduct (GDP) and the Education Index (EI). We present rankings, which are\nbased either on the Hirsch Index H, or on the linear combination $\\Sigma = E +\nP + 0.05 C$. We consider both extensive and intensive national statistics, i.e.\nabsolute and relative to the population or to the GDP.",
        "positive": "Radiative contribution to the effective potential in a composite Higgs\n  model: The SU(4) gauge theory with two flavors of Dirac fermions in the sextet\nrepresentation shares features of a candidate for a composite Higgs model. The\nanalogue of the Higgs multiplet of the Standard Model lives in the Goldstone\nmanifold resulting from spontaneous breaking of the global symmetry SU(4) to\nSO(4). The Higgs potential arises from interaction with the particles of the\nStandard Model. We have computed the gauge boson contribution to the Higgs\npotential, using valence overlap fermions on a Wilson-clover sea. The\ncalculation is similar to that of the electromagnetic mass splitting of the\npion multiplet in QCD."
    },
    {
        "anchor": "The isentropic equation of state of (2+1)-flavor QCD: An update based on\n  high precision Taylor expansion and Pad\u00e9-resummed expansion at finite\n  chemical potentials: The HotQCD Collaboration performed Taylor expansion calculations in 2017 for\nthe pressure, energy density, and entropy density at non-zero chemical\npotentials up to the $6^{th}$ order. Since then, they have significantly\nimproved the statistics for lattices with temporal extents of $N_\\tau=8$ and\n$12$, and have also included results for $N_\\tau=16$ that were not previously\navailable. They have also calculated the $8^{th}$-order expansion coefficients\nfor $N_\\tau=8$. These calculations showed that the Taylor series expansion for\nthe pressure is accurate up to $\\mu_B / T \\leq 2.5$. In this study, we use the\nhigh-statistics results on Taylor expansion coefficients, calculated with HISQ\nfermions and extrapolated to the continuum limit, to determine the QCD equation\nof state under conditions relevant for hot and dense matter produced in heavy\nion collisions. We also calculate the energy density and pressure along lines\nof constant entropy per net baryon number.",
        "positive": "Gauge Invariant Smearing and Matrix Correlators using Wilson Fermions at\n  beta=6.2: We present an investigation of gauge invariant smearing for Wilson fermions\non a $24^3 \\times 48$ lattice at $\\beta = 6.2$. We demonstrate a smearing\nalgorithm that allows a substantial improvement in the determination of the\nbaryon spectrum obtained using propagators smeared at both source and sink, at\nonly a small computational cost. We investigate the matrix of correlators\nconstructed from local and smeared operators, and are able to expose excited\nstates of both the mesons and baryons."
    },
    {
        "anchor": "Lattice calculation of the short and intermediate time-distance hadronic\n  vacuum polarization contributions to the muon magnetic moment using\n  twisted-mass fermions: We present a lattice determination of the leading-order hadronic vacuum\npolarization (HVP) contribution to the muon anomalous magnetic moment,\n$a_{\\mu}^{\\rm HVP}$, in the so-called short and intermediate time-distance\nwindows, $a_{\\mu}^{\\rm SD}$ and $a_{\\mu}^{\\rm W}$, defined by the RBC/UKQCD\nCollaboration [1]. We employ gauge ensembles produced by the Extended Twisted\nMass Collaboration (ETMC) with $N_f = 2 + 1 + 1$ flavors of Wilson-clover\ntwisted-mass quarks with masses of all the dynamical quark flavors tuned close\nto their physical values. The simulations are carried out at three values of\nthe lattice spacing equal to $\\simeq 0.057, 0.068$ and $0.080$ fm with spatial\nlattice sizes up to $L \\simeq 7.6$~fm. For the short distance window we obtain\n$a_\\mu^{\\rm SD}({\\rm ETMC}) = 69.27\\,(34) \\cdot 10^{-10}$, which is consistent\nwith the recent dispersive value of $a_\\mu^{\\rm SD}(e^+ e^-) = 68.4\\,(5) \\cdot\n10^{-10}$ [2]. In the case of the intermediate window we get the value\n$a_\\mu^{\\rm W}({\\rm ETMC}) = 236.3\\,(1.3) \\cdot 10^{-10}$, which is consistent\nwith the result $a_\\mu^{\\rm W}({\\rm BMW}) = 236.7\\,(1.4) \\cdot 10^{-10}$ [3] by\nthe BMW collaboration as well as with the recent determination by the CLS/Mainz\ngroup of $a_\\mu^{\\rm W}({\\rm CLS}) = 237.30\\,(1.46) \\cdot 10^{-10}$ [4].\nHowever, it is larger than the dispersive result of $a_\\mu^{\\rm W}(e^+ e^-) =\n229.4\\,(1.4) \\cdot 10^{-10}$ [2] by approximately $3.6$ standard deviations.\nThe tension increases to approximately $4.5$ standard deviations if we average\nour ETMC result with those by BMW and CLS/Mainz. Our accurate lattice results\nin the short and intermediate windows point to a possible deviation of the $e^+\ne^-$ cross section data with respect to Standard Model predictions in the low\nand intermediate energy regions, but not in the high energy region.",
        "positive": "A Chiral Phase Transition using a Fermion Cluster Algorithm: The recent solution to the fermion sign problem allows, for the first time,\nthe use of cluster algorithm techniques to compute certain fermionic path\nintegrals. To illustrate the underlying ideas behind the progress, a cluster\nalgorithm is constructed to study the chiral phase transition in a strongly\ninteracting staggered fermion model with an arbitrary mass term in 3+1\ndimensions. Unlike conventional methods there is no difficulty in the cluster\nmethod to approach the chiral (massless) limit. Results using the new algorithm\nconfirm that the chiral transition falls under the expected universality class."
    },
    {
        "anchor": "Lattice Dirac Fermions on a Simplicial Riemannian Manifold: The lattice Dirac equation is formulated on a simplicial complex which\napproximates a smooth Riemann manifold by introducing a lattice vierbein on\neach site and a lattice spin connection on each link. Care is taken so the\nconstruction applies to any smooth D-dimensional Riemannian manifold that\npermits a spin connection. It is tested numerically in 2D for the projective\nsphere ${\\mathbb S}^2$ in the limit of an increasingly refined sequence of\ntriangles. The eigenspectrum and eigenvectors are shown to converge rapidly to\nthe exact result in the continuum limit. In addition comparison is made with\nthe continuum Ising conformal field theory on ${\\mathbb S}^2$. Convergence is\ntested for the two point, $\\langle \\epsilon(x_1) \\epsilon(x_2) \\rangle$, and\nthe four point, $\\langle \\sigma(x_1) \\epsilon(x_2) \\epsilon(x_3 )\\sigma(x_4)\n\\rangle $, correlators for the energy, $\\epsilon(x) = i \\bar \\psi(x)\\psi(x)$,\nand twist operators, $\\sigma(x)$, respectively.",
        "positive": "Choice of Integrator in the Hybrid Monte Carlo Algorithm: We study efficiency of higher order integrator schemes for the hybrid Monte\nCarlo (HMC) algorithm. Numerical tests are performed for Quantum Chromo\nDynamics (QCD) with two flavors of Wilson fermions. We compare 2nd, 4th and 6th\norder integrators at various quark masses. The performance depends on both\nvolume and quark mass. On currently accessible large lattices ($V \\sim 24^4$),\nhigher order integrators can be more efficient than the 2nd order one only in\nheavy quark region, $m_q a > 0.3$. Thus we conclude that for most full QCD\nsimulations, except for heavy quark case, the usual 2nd order integrator is the\nbest choice."
    },
    {
        "anchor": "The large-mass regime of confining but nearly conformal gauge theories: We apply a recently developed dilaton-pion effective field theory for\nasymptotically free gauge theories near the conformal window to the $SU(3)$\ngauge theory with $N_f=8$ fermions in the fundamental representation. Numerical\ndata for this theory suggest the existence of a large-mass regime, where the\nfermion mass is not small but nevertheless the effective theory is applicable\nbecause of the parametric proximity of the conformal window. In this regime, we\nfind that the mass dependence of hadronic quantities is similar to that of a a\nmass-deformed conformal theory, so that distinguishing infrared conformality\nfrom confinement requires the study of subleading effects.",
        "positive": "Multi-meson States in Lattice QCD: In this contribution, I summarise the studies of the properties of\nBose-Einstein condensed systems composed of up to twelve pions or kaons carried\nout by the NPLQCD collaboration. These investigations have provided precise\ndetermination the I=2 pi-pi and I=1 K-K scattering lengths and the first\ndetermination of three-hadron interactions from QCD, finding a repulsive\nthree-pion interaction of size consistent with naive dimensional analysis and a\nthree kaon interaction consistent with zero. We have also determined the\nisospin (strangeness) density dependence of the isospin (strangeness) chemical\npotential, finding results in surprisingly good agreement with chiral\nperturbation theory."
    },
    {
        "anchor": "The Ds and D+ Leptonic Decay Constants from Lattice QCD: We present the leptonic decay constants fDs and fD+ computed on the MILC\ncollaboration's 2+1 flavor asqtad gauge ensembles. We use clover heavy quarks\nwith the Fermilab interpretation and improved staggered light quarks. The\nsimultaneous chiral and continuum extrapolation, which determines both decay\nconstants, includes partially-quenched lattice results at lattice spacings a ~\n0:09, 0:12 and 0:15 fm. We have made several recent improvements in our\nanalysis: a) we include terms in the fit describing leading order heavy-quark\ndiscretization effects, b) we have adopted a more precise input r1 value\nconsistent with our other D and B meson studies, c) we have retuned the input\nbare charm masses based upon the new r1. Our preliminary results are fDs = 260\n+/-10 MeV and fD+ = 217 +/-10 MeV.",
        "positive": "Implications of $Tr\u03b3_{5}=0$ in Lattice Gauge Theory: We analyze the implications of the relation $Tr\\gamma_{5}=0$, which is\ncustomarily assumed in practical lattice calculations. On the basis of the\nfinite dimensional representations of the Ginsparg-Wilson algebra, it is shown\nthat this relation reflects the species doubling in lattice theory; topological\nexcitations associated with species doublers, which have eigenvalue $2/a$,\ncontribute to $Tr\\gamma_{5}$ without any suppression. In this sense, the\nrelation $Tr\\gamma_{5}=0$ is valid only when we allow the presence of\nunphysical states in the Hilbert space; this statement is also valid in the\nPauli-Villars regularization. If one eliminates the contributions of the\nunphysical states, the trace $Tr\\gamma_{5}$ is replaced by $Tr\\Gamma_{5}\\equiv\nTr \\gamma_{5}(1 -{1/2}aD)$ which gives rise to the Pontryagin index, to be\nconsistent with the continuum analysis."
    },
    {
        "anchor": "Nucleon form factors with light Wilson quarks: We present nucleon observables - primarily isovector vector form factors -\nfrom calculations using 2+1 flavors of Wilson quarks. One ensemble is used for\na dedicated high-precision study of excited-state effects using five\nsource-sink separations between 0.7 and 1.6 fm. We also present results from a\nlarger set of calculations that include an ensemble with pion mass 149 MeV and\nbox size 5.6 fm, which nearly eliminates the uncertainty associated with\nextrapolation to the physical pion mass. The results show agreement with\nexperiment for the vector form factors, which occurs only when excited-state\ncontributions are reduced. Finally, we show results from a subset of ensembles\nthat have pion mass 254 MeV with varying temporal and spatial box sizes, which\nwe use for a controlled study of finite-volume effects and a test of the\n\"$m_\\pi L=4$\" rule of thumb.",
        "positive": "The Three-Loop Lattice Free Energy: We calculate the free energy of SU(N) gauge theories on the lattice, to three\nloops. Our result, combined with Monte Carlo data for the average plaquette,\ngives a more precise estimate of the gluonic condensate."
    },
    {
        "anchor": "Perturbative renormalization factors of four-quark operators for\n  improved Wilson fermion action and Iwasaki gauge action: The renormalization factor and O(a) improvement coefficient of four-quark\noperators are calculated perturbatively for the improved Wilson fermion action\nwith clover term and the Iwasaki gauge action. With an application to the\n$K\\to\\pi\\pi$ decay amplitude in mind, the calculation is restricted to the\nparity odd operator, for which the operators are multiplicatively renormalized\nwithout any mixing to operators that have different chiral structures.",
        "positive": "Hybrid Monte Carlo on Lefschetz Thimbles -- A study of the residual sign\n  problem: We consider a hybrid Monte Carlo algorithm which is applicable to lattice\ntheories defined on Lefschetz thimbles. In the algorithm, any point (field\nconfiguration) on a thimble is parametrized uniquely by the flow-direction and\nthe flow-time defined at a certain asymptotic region close to the critical\npoint, and it is generated by solving the gradient flow equation downward. The\nassociated complete set of tangent vectors is also generated in the same\nmanner. Molecular dynamics is then formulated as a constrained dynamical\nsystem, where the equations of motion with Lagrange multipliers are solved by\nthe second-order constraint-preserving symmetric integrator. The algorithm is\ntested in the lambda phi^4 model at finite density, by choosing the thimbles\nassociated with the classical vacua for subcritical and supercritical values of\nchemical potential. For the lattice size L=4, we find that the residual sign\nfactors average to not less than 0.99 and are safely included by reweighting\nand that the results of the number density are consistent with those obtained\nby the complex Langevin simulations."
    },
    {
        "anchor": "Recent Developments in Lattice Studies for Quarkonia: After discussing results of dilepton rates and electrical conductivity\nobtained from continuum extrapolated results of light quark correlation\nfunctions in quenched QCD I will give a review on recent developments in\nlattice QCD studies for quarkonia in the quark gluon plasma. Recent progress in\nthe extraction of spectral properties from lattice QCD calculations of hadronic\ncorrelation functions will be discussed. Besides medium modifications of bound\nstates and their dissociation in the plasma I will focus on transport\ncoefficients, like heavy quark diffusion constants extracted from different\ncorrelation functions on the lattice. Present limitations and future\nperspectives for studies of quarkonia and related transport coefficients on the\nlattice will be discussed.",
        "positive": "Meson and Baryon dispersion relations with Brillouin fermions: We study the dispersion relations of mesons and baryons built from Brillouin\nquarks on one N_f=2 gauge ensemble provided by QCDSF. For quark masses up to\nthe physical strange quark mass, there is hardly any improvement over the\nWilson discretization, if either action is link-smeared and tree-level clover\nimproved. For quark masses in the range of the physical charm quark mass, the\nBrillouin action still shows a perfect relativistic behavior, while the Wilson\naction induces severe cut-off effects. As an application we determine the\nmasses of the \\Omega_c^0, \\Omega_{cc}^+ and \\Omega_{ccc}^{++} baryons on that\nensemble."
    },
    {
        "anchor": "Multicritical Points in a Lattice Yukawa Model with the Wilson-Yukawa\n  Coupling: For a lattice regularized chiral-invariant $SU(2)_L\\times~SU(2)_R$\nfermion-scalar model with a Yukawa coupling $y$ and a Wilson-Yukawa coupling\n$w$, we investigate the phase structure and in particular show the existence of\nthe multicritical line, in the strong Yukawa and/or Wilson Yukawa coupling\nregion, at which four phases meet.\n  The result is in good agreement with the Monte Carlo simulation.\n  This analytical result is derived from the effective scalar model obtained by\nintegrating out the fermion field where the action is explicitly obtained from\nthe hopping parameter expansion up to next-to-leading order.\n  For estimates on the correlation function of the scalar field we apply the\nmean-field method.",
        "positive": "Neutron Electric Dipole Moment from Beyond the Standard Model: We present an update on our calculations of the matrix elements of the CP\nviolating quark and gluon chromo-EDM operators, as well as the operators these\nmix with, such as the QCD Theta-term. Their contribution to the neutron EDM is\nobtained by extrapolating the $F_3$ form factor of a vector current to zero\nmomentum transfer. The calculation is being done using valence Wilson-clover\nquarks on HISQ background configurations generated by the MILC collaboration."
    },
    {
        "anchor": "Bubble nucleation and quantum initial conditions in classical\n  statistical simulations: Classical-statistical lattice simulations provide a useful approximation to\nout-of-equilibrium quantum field theory, but only for systems exhibiting large\noccupation numbers, and only for phenomena that are not intrinsically quantum\nmechanical in nature. In certain special circumstances, it can be appropriate\nto initialize such real-time simulations with quantum-like zero-point\nfluctuations. We will revisit these points, and investigate reports that\nquantum bubble nucleation rates in 1+1 dimensions can be computed through the\nclassical evolution of such a quantum-like initial condition. We find that\nalthough intriguing, the reported numerical agreement between\nclassical-statistical simulations and the quantum nucleation rate in 1+1\ndimensions is a coincidence, which is not specific to this choice of\ninitialisation, is parameter and lattice cut-off dependent and disappears as\nthe number of space-dimensions increases from 1+1 to 2+1",
        "positive": "Hubbard Model with Luscher fermions - a progress report: Some modifications of the Luscher algorithm, which reduce the autocorelation\ntime, are proposed and tested."
    },
    {
        "anchor": "Color Dynamics in External Fields: We investigate the vacuum dynamics of U(1), SU(2), and SU(3) lattice gauge\ntheories in presence of external (chromo)magnetic fields, both in (3+1) and\n(2+1) dimensions. We find that the critical coupling for the phase transition\nin compact U(1) gauge theory is independent of the strength of an external\nmagnetic field. On the other hand we find that, both in (3+1) and (2+1)\ndimensions, the deconfinement temperature for SU(2) and SU(3) gauge systems in\na constant abelian chromomagnetic field decreases when the strength of the\napplied field increases. We conclude that the dependence of the deconfinement\ntemperature on the strength of an external constant chromomagnetic field is a\npeculiar feature of non abelian gauge theories and could be useful to get\ninsight into color confinement.",
        "positive": "Antistatic-antistatic-light-light potentials from lattice QCD: We present results for tetraquark potentials of two static anti-quarks $\\bar\nb \\bar b$ in the presence of two light quarks $u$ and/or $d$. We improve on\nexisting results by computing the static potential also for off-axis\nseparations, which increases the number of data points significantly. Moreover,\nwe compute for the first time $\\bar b \\bar b u s$ potentials."
    },
    {
        "anchor": "Lambda-parameter of lattice QCD with Symanzik improved gluon actions: We compute the ratio Lambda_L/Lambda_MS, where the scale parameter Lambda_L\nis associated with a lattice formulation of QCD. We consider a 3-parameter\nfamily of gluon actions, which are most frequently used for O(a) improvement a`\nla Symanzik. The gluon action is put togeter with standard discretizations for\nfermions (Wilson/clover, overlap), to provide Lambda_L for several possible\ncombinations of fermion and gluon actions. We employ the background field\ntechnique in order to calculate the 1PI 2-point function of the background\nfield; this leads to the coupling constant renormalization function, Z_g, at\n1-loop level.\n  Our results are obtained for an extensive range of values for the Symanzik\ncoefficients.",
        "positive": "Lattice Dirac operators with chiral chemical potential: This paper has been withdrawn by the author."
    },
    {
        "anchor": "Computation of QCD meson screening masses at high temperature: We compute flavor non-singlet meson screening masses in the chiral limit of\nQCD with $N_f=3$ quarks. The calculation is carried out at 12 temperatures from\n$T\\approx 1$ GeV up to the electroweak scale. For each temperature we simulated\nseveral lattice spacings, so as to be able to perform the continuum limit\nextrapolation with confidence at a few permille accuracy. In the entire range\nof temperatures explored, the meson screening masses deviate from the free\ntheory result $2\\pi T$ by at most a few percent. Their values, however, cannot\nbe explained by one-loop perturbation theory up to the electroweak scale, where\nthe pseudoscalar and the vector screening masses are still significantly\ndifferent within our precision. Chiral symmetry restoration manifests itself\nthrough the degeneracy of the pseudoscalar and the scalar channels and of the\nvector and the axial ones.",
        "positive": "Study of Possible Proton-Antiproton Hexaquark State in Lattice QCD: We have used standard techniques of lattice quantum chromodynamics to look\nfor evidence of the spin-zero six quark flavour singlet state ($J^{PC}=0^{-+}$)\nobserved by BES Collaboration, and to determine the splitting between the mass\nof the possible proton-antiproton and the mass of two protons, its threshold.\nUsing the various interpolating fields we find indications that for\nsufficiently light quarks proton-antiproton is slightly above the $2m_{p}$\nthreshold. The lattice resonance signal of binding observed near the physical\nand continuum regimes do not support the existence of proton-antiproton state\nas a spin-zero hexaquark state."
    },
    {
        "anchor": "Simulations of Lattice Fermions with Chiral Symmetry in Quantum\n  Chromodynamics: This thesis is dedicated to explore the feasibility of numerical calculations\nin the $\\epsilon$--regime of QCD for the extraction of physical information. We\napply two formulations of the Ginsparg-Wilson fermions the Neuberger operator\nand the hypercube overlap operator to compute the observables of interest. As a\nmain result we present the comparison of the distributions of the leading\nindividual eigenvalues of the Neuberger operator in QCD and the analytical\npredictions of chiral random matrix theory. We observe a good agreement as long\nas each side of the physical volume exceeds about $L\\approx 1.12\\fm$. It turns\nout that this bound for $L$ is generic and sets the size of the physical volume\nwhere the axial correlator behaves according to chiral perturbation theory.\nThis allows us to compute a value for the pion decay constant $F_{\\pi}$. As an\nalternative procedure we only consider the contribution from the zero modes.\nHere we are able to obtain an estimate for $F_{\\pi}$ and $\\alpha$. As a\ntheoretical development the L\\\"uscher topology conserving gauge action is\ninvestigated. This enables us to sample the observables of interest in the\n$\\epsilon$--regime without recomputing the index. We can report that a\npromising gauge action has been identified.",
        "positive": "Accessing directly the properties of fundamental scalars in the\n  confinement and Higgs phase: The properties of elementary particles are encoded in their respective\npropagators and interaction vertices. For a SU(2) gauge theory coupled to a\ndoublet of fundamental complex scalars these propagators are determined in both\nthe Higgs phase and the confinement phase and compared to the Yang-Mills case,\nusing lattice gauge theory. Since the propagators are gauge-dependent, this is\ndone in the Landau limit of 't Hooft gauge, permitting to also determine the\nghost propagator. It is found that neither the gauge boson nor the scalar\ndiffer qualitatively in the different cases. In particular, the gauge boson\nacquires a screening mass, and the scalar's screening mass is larger than the\nrenormalized mass. Only the ghost propagator shows a significant change.\nFurthermore, indications are found that the consequences of the residual\nnon-perturbative gauge freedom due to Gribov copies could be different in the\nconfinement and the Higgs phase."
    },
    {
        "anchor": "Lattice Quantum Electrodynamics in (3+1)-dimensions at finite density\n  with Tensor Networks: Gauge theories are of paramount importance in our understanding of\nfundamental constituents of matter and their interactions. However, the\ncomplete characterization of their phase diagrams and the full understanding of\nnon-perturbative effects are still debated, especially at finite charge\ndensity, mostly due to the sign-problem affecting Monte Carlo numerical\nsimulations. Here, we report the Tensor Network simulation of a three\ndimensional lattice gauge theory in the Hamiltonian formulation including\ndynamical matter: Using this sign-problem-free method, we simulate the ground\nstates of a compact Quantum Electrodynamics at zero and finite charge\ndensities, and address fundamental questions such as the characterization of\ncollective phases of the model, the presence of a confining phase at large\ngauge coupling, and the study of charge-screening effects.",
        "positive": "Low energy constant and mixed-action effect: We present the pion mass and decay constant using the overlap fermion valence\non domain wall (DW) fermion sea at several lattice spacings. The mixed action\neffect in the lattice calculation is also studied, and the result suggests that\nthe mixed action effect with the overlap valence on DW sea would be\nproportional to the fourth power of the lattice spacing. We obtain the pion\ndecay constant at the physical pion mass and $N_f=2$ chiral limit to be\n$92.4(3)(2)~{\\rm MeV}$ and $87.0(5)(7)~{\\rm MeV}$ respectively; and the\nphysical u/d averaged quark mass at $\\overline{\\textrm{MS}}$ 2 GeV is\n$3.74(4)(5)(5)(3)~{\\rm MeV}$ with the linear ${\\cal O}(a^2)$ continuum\nextrapolation. Using the FLAG value of the NLO low energy constant, we obtain\nthe $N_f=2$ chiral condensate to be $\\Sigma^{\\overline{\\textrm{MS}}(2~{\\rm\nGeV})}=\\big(266(2)(1)~{\\rm MeV}\\big)^3$."
    },
    {
        "anchor": "Finite density condensation and scattering data - a study in $\u03c6^4$\n  lattice field theory: We study the quantum field theory of a charged $\\phi^4$ field in lattice\nregularization at finite density and low temperature in 2 and 4 dimensions with\nthe goal of analyzing the connection of condensation phenomena to scattering\ndata in a non-perturbative way. The sign problem of the theory at non-zero\nchemical potential $\\mu$ is overcome by using a worldline representation for\nthe Monte Carlo simulation. At low temperature we study the particle number as\na function of $\\mu$ and observe the steps for $\\mbox{1-,}$ 2- and 3-particle\ncondensation. We determine the corresponding critical values $\\mu_n^{crit}, \\,\nn = 1,2,3$ and analyze their dependence on the spatial extent $L$ of the\nlattice. Linear combinations of the $\\mu_n^{crit}$ give the interaction\nenergies in the 2- and 3-particle sectors and their dependence on $L$ is\nrelated to scattering data by L\\\"uscher's formula and its generalizations to\nthree particles. For 2-$d$ we determine the scattering phase shift and for\n4-$d$ the scattering length. We cross-check our results with a determination of\nthe mass and the 2- and 3-particle energies from conventional 2-, 4-, and\n6-point correlators at zero chemical potential. The letter demonstrates that\nthe physics of condensation at finite density and low temperature is closely\nrelated to scattering data of a quantum field theory.",
        "positive": "Some results on excited hadrons in 2-flavor QCD: Results of hadron spectroscopy with two dynamical mass-degenerate chirally\nimproved quarks are presented. Three ensembles with pion masses of 322(5),\n470(4) and 525(7) MeV, lattices of size 16^3 \\times 32, and lattice spacings\nclose to 0.15 fm are investigated. We discuss the possible appearance of\nscattering states, considering masses and eigenvectors. Partially quenched\nresults in the scalar channel suggest the presence of a 2-particle state,\nhowever, in most channels we cannot identify them. Where available, we compare\nto results from quenched simulations using the same action."
    },
    {
        "anchor": "Studying the gradient flow coupling in the Schr\u00f6dinger functional: We discuss the setup and features of a new definition of the running coupling\nin the Schr\\\"odinger functional scheme based on the gradient flow. Its\nsuitability for a precise continuum limit in QCD is demonstrated on a set of\nNf=2 gauge field ensembles in a physical volume of L~0.4fm.",
        "positive": "Renormalization Group Therapy: We point out a general problem with the procedures commonly used to obtain\nimproved actions from MCRG decimated configurations. Straightforward\nmeasurement of the couplings from the decimated configurations, by one of the\nknown methods, can result into actions that do not correctly reproduce the\nphysics on the undecimated lattice. This is because the decimated\nconfigurations are generally not representative of the equilibrium\nconfigurations of the assumed form of the effective action at the measured\ncouplings. Curing this involves fine-tuning of the chosen MCRG decimation\nprocedure, which is also dependent on the form assumed for the effective\naction. We illustrate this in decimation studies of the SU(2) LGT using\nSwendsen and Double Smeared Blocking decimation procedures. A single-plaquette\nimproved action involving five group representations and free of this pathology\nis given."
    },
    {
        "anchor": "Tensor network formulation of the massless Schwinger model: We construct a tensor network representation of the partition function for\nthe massless Schwinger model on a two dimensional lattice using staggered\nfermions. The tensor network representation allows us to include a topological\nterm. Using a particular implementation of the tensor renormalization group\n(HOTRG) we calculate the phase diagram of the theory. For a range of values of\nthe coupling to the topological term $\\theta$ and the gauge coupling $\\beta$ we\ncompare with results from hybrid Monte Carlo when possible and find good\nagreement.",
        "positive": "Dual condensate and QCD phase transition: The dual condensate is a new QCD phase transition order parameter, which\nconnnects confinement and chiral symmetry breaking as different mass limits. We\ndiscuss the relation between the fermion spectrum at general boundary\nconditions and the dual condensate and show numerical results for the latter\nfrom unquenched SU(3) lattice configurations."
    },
    {
        "anchor": "Extended Mean Field study of complex $\u03c6^4$-theory at finite density\n  and temperature: We review the Extended Mean Field Theory (EMFT) approximation and apply it to\ncomplex, scalar $\\phi^4$-theory on the lattice. We study the critical\nproperties of the Bose condensation driven by a nonzero chemical potential\n$\\mu$ at both zero and nonzero temperature and determine the $(T,\\mu)$ phase\ndiagram. The results are in very good agreement with recent Monte Carlo data\nfor all parameter values considered. EMFT can be formulated directly in the\nthermodynamic limit which allows us to study lattice spacings for which Monte\nCarlo studies are not feasible with present techniques. We find that the EMFT\napproximation accurately reproduces many known phenomena of the exact solution,\nlike the \"Silver Blaze\" behavior at zero temperature and dimensional reduction\nat finite temperature.",
        "positive": "Genetic Algorithm for SU(N) gauge theory on a lattice: An Algorithm is proposed for the simulation of pure SU(N) lattice gauge\ntheories based on Genetic Algorithms(GAs). Main difference between GAs and\nMetropolis methods(MPs) is that GAs treat a population of points at once, while\nMPs treat only one point in the searching space. This provides GAs with\ninformation about the assortment as well as the fitness of the evolution\nfunction and producting a better solution. We apply GAs to SU(2) pure gauge\ntheory on a 2 dimensional lattice and show the results are consistent with\nthose given by MP and Heatbath methods(HBs). Thermalization speed of GAs is\nespecially faster than the simple MPs."
    },
    {
        "anchor": "Symanzik effective actions in the large N limit: Symanzik effective actions, conjectured to describe lattice artifacts, are\ndetermined for a class of lattice regularizations of the non-linear O(N) sigma\nmodel in two dimensions in the leading order of the 1/N-expansion. The class of\nactions considered includes also ones which do not have the usual classical\nlimit and are not (so far) treatable in the framework of ordinary perturbation\ntheory. The effective actions obtained are shown to reproduce previously\ncomputed lattice artifacts of the step scaling functions defined in finite\nvolume, giving further confidence in Symanzik's theory of lattice artifacts.",
        "positive": "Partial-Global Stochastic Metropolis Update for Dynamical Smeared Link\n  Fermions: We performed dynamical simulations with HYP smeared staggered fermions using\nthe recently proposed partial-global stochastic Metropolis algorithm with\nfermion matrix reduction and determinant breakup improvements. In this paper we\ndiscuss our choice of the action parameters and study the autocorrelation time\nboth with four and two fermionic flavors at different quark mass values on\napproximately 10 fm^4 lattices. We find that the update is especially efficient\nwith two flavors making simulations on larger volumes feasible."
    },
    {
        "anchor": "$I=2$ pion scattering amplitude with Wilson fermions: We present an exploratory calculation of the $I=2$ $\\pi-\\pi$ scattering\namplitude at threshold using Wilson fermions in the quenched approximation,\nincluding all the required contractions. We find good agreement with the\npredictions of chiral perturbation theory even for pions of mass 560-700 MeV.\nWithin the 10\\% errors, we do not see the onset of the bad chiral behavior\nexpected for Wilson fermions. We also derive rigorous inequalities that apply\nto 2-particle correlators and as a consequence show that the interaction in the\nantisymmetric state of two pions has to be attractive.",
        "positive": "Absence of barriers in dynamical triangulation: Due to the unrecognizability of certain manifolds there must exist pairs of\ntriangulations of these manifolds that can only be reached from each other by\ngoing through an intermediate state that is very large. This might reduce the\nreliability of dynamical triangulation, because there will be states that will\nnot be reached in practice. We investigate this problem numerically for the\nmanifold $S^5$, which is known to be unrecognizable, but see no sign of these\nunreachable states."
    },
    {
        "anchor": "Hadron structure with light dynamical quarks: Generalized parton distributions encompass a wealth of information concerning\nthe three-dimensional quark and gluon structure of the nucleon, and thus\nprovide an ideal focus for the study of hadron structure using lattice QCD. The\nspecial limits corresponding to form factors and parton distributions are well\nexplored experimentally, providing clear tests of lattice calculations, and the\nlack of experimental data for more general cases provides opportunities for\ngenuine predictions and for guiding experiment. We present results from hybrid\ncalculations with improved staggered (Asqtad) sea quarks and domain wall\nvalence quarks at pion masses down to 350 MeV.",
        "positive": "Non-perturbative improvement of nHYP smeared Wilson fermions: Using Schroedinger functional techniques, we determine the coefficient of the\nclover term necessary for non-perturbative O(a) improvement of hypercubic\nsmeared Wilson fermions on a quenched plaquette action background. Unlike for\nunsmeared Wilson fermions, the resulting clover coefficients are close to the\ntree-level value even at coarse lattice spacings, indicating the absence of\nlarge cutoff effects. A number of exploratory tests are also performed with the\nimproved action."
    },
    {
        "anchor": "Finite Temperature Phase Diagrams of Gauge Theories: We discuss finite temperature phase diagrams of SU(N) gauge theory with\nmassless fermions as a function of the number of fermion flavors. Inside the\nconformal window we find a phase boundary separating two different conformal\nphases. Below the conformal window we find different phase structures depending\non if the beta function of the theory has a first or higher order zero at the\nlower boundary of the conformal window. We also outline how the associated\nbehaviors will help in distinguishing different types of theories using lattice\nsimulations.",
        "positive": "Positive Representations of a Class of Complex Measures: We study the problem of constructing positive representations of complex\nmeasures. In this paper we consider complex densities on a direct product of\n$U(1)$ groups and look for representations by probability distributions on the\ncomplexification of those groups. After identifying general necessary and\nsufficient conditions we propose several concrete realizations. Finally we\nstudy some of those realizations in examples representing problems in abelian\nlattice gauge theories."
    },
    {
        "anchor": "QCD Phase Transition in a Strong Magnetic Background: We investigate the properties of the deconfining/chiral restoring transition\nfor two flavor QCD in presence of a uniform background magnetic field. We adopt\na standard staggered discretization of the fermion action and a lattice spacing\nof the order of 0.3 fm. We explore different values of the bare quark mass,\ncorresponding to pion masses in the range 200 - 480 MeV, and magnetic fields up\nto |e|B ~ 0.75 GeV^2. The deconfinement and chiral symmetry restoration\ntemperatures remain compatible with each other and rise very slightly (< 2 %\nfor our largest magnetic field) as a function of the magnetic field. On the\nother hand, the transition seems to become sharper as the magnetic field\nincreases.",
        "positive": "Survival of charmonia above Tc in anisotropic lattice QCD: We find a strong evidence for the survival of $J/\\Psi$ and $\\eta_c$ as\nspatially-localized $c\\bar c$ (quasi-)bound states above the QCD critical\ntemperature $T_c$, by investigating the boundary-condition dependence of their\nenergies and spectral functions. In a finite-volume box, there arises a\nboundary-condition dependence for spatially spread states, while no such\ndependence appears for spatially compact states. In lattice QCD, we find almost\n{\\it no} spatial boundary-condition dependence for the energy of the $c\\bar c$\nsystem in $J/\\Psi$ and $\\eta_c$ channels for $T\\simeq(1.11-2.07)T_c$. We also\ninvestigate the spectral function of charmonia above $T_c$ in lattice QCD using\nthe maximum entropy method (MEM) in terms of the boundary-condition dependence.\nThere is {\\it no} spatial boundary-condition dependence for the low-lying peaks\ncorresponding to $J/\\Psi$ and $\\eta_c$ around 3GeV at $1.62T_c$. These facts\nindicate the survival of $J/\\Psi$ and $\\eta_c$ as compact $c\\bar c$\n(quasi-)bound states for $T_c < T < 2T_c$."
    },
    {
        "anchor": "Chiral Gauge Theory on Lattice with Domain Wall Fermions: We investigate a U(1) lattice chiral gauge theory with domain wall fermions\nand compact gauge fixing. In the reduced model limit, our perturbative and\nnumerical investigations show that there exist no extra mirror chiral modes.\nThe longitudinal gauge degrees of freedom have no effect on the free domain\nwall fermion spectrum consisting of opposite chiral modes at the domain wall\nand at the anti-domain wall which have an exponentially damped overlap.",
        "positive": "Mesonic Form Factors: We have started a program to compute the electromagnetic form factors of\nmesons. We discuss the techniques used to compute the pion form factor and\npresent preliminary results computed with domain wall valence fermions on MILC\nasqtad lattices, as well as Wilson fermions on quenched lattices. These methods\ncan easily be extended to rho-to-gamma-pi transition form factors."
    },
    {
        "anchor": "Aspects of topological actions on the lattice: We consider a lattice action which forbids large fields, and which remains\ninvariant under smooth deformations of the field. Such a \"topological\" action\ndepends on one parameter, the field cutoff, but does not have a classical\ncontinuum limit as this cutoff approaches zero. We study the properties of such\nan action in 4d compact U(1) lattice gauge theory, and compare them with those\nof the Wilson action. In both cases, we find a weakly first-order transition\nseparating a confining phase where monopoles condense, and a Coulomb phase\nwhere monopoles are exponentially suppressed. We also find a different,\ncritical value of the field cutoff where monopoles completely disappear.\nFinally, we show that a topological action simplifies the measurement of the\nfree energy.",
        "positive": "Calculation of Neutron EDM in quenched and full QCD: We report on a direct lattice calculation of the neutron EDM(NEDM) using the\nexternal electric field method in both quenched and full QCD. In quenched QCD,\nwe use a $24^3\\times 32$ lattice at $\\beta=2.6$ with the Iwasaki gauge action\nand the clover fermion action to examine the viability of this method. In\nparticular we investigate possible effects of violation of the periodic\nboundary condition of the external electric field on the NEDM signal. We also\nstudy the quark mass dependence of NEDM in quenched QCD, and observe that NEDM\nseems to remain non-zero toward the chiral limit because of the quenched\nartifact. In 2-flavor full QCD we employ configurations generated by the\nCP-PACS collaboration on a $24^3\\times 48$ lattice at $\\beta=2.1$ with the same\ngluon and quark actions as in the quenched case. Since the number of\nconfigurations is limited, we employ 8 different source points per one\nconfiguration and take an average over them. Our preliminary result at three\nquark masses ($m_{PS}/m_V\\simeq 0.81, 0.76, 0.69$) indicates that non-zero\nvalue for NEDM can be obtained in full QCD. Statistical errors, however, are\nstill too large to show the theoretically expected behaviour for NEDM in full\nQCD that it vanishes in the chiral limit."
    },
    {
        "anchor": "The Confined-Deconfined Interface Tension in Quenched QCD using the\n  Histogram Method: We present results for the confinement-deconfinement interface tension\n$\\sigma_{cd}$ of quenched QCD. They were obtained by applying Binder's\nhistogram method to lattices of size $L^2\\times L_z\\times L_t$ for $L_t=2$ and\n$L=8,10,12\\mbox{ and }14$ and various $L_z\\in [L,\\, 4\\, L]$. The use of a\nmulticanonical algorithm and rectangular geometries have turned out to be\ncrucial for the numerical studies. We also give an estimate for $\\sigma_{cd}$\nat $L_t=4$ using published data.",
        "positive": "SSOR preconditioning in simulations of the QCD Schr\u00f6dinger functional: We report on a parallelized implementation of SSOR preconditioning for O(a)\nimproved lattice QCD with Schr\\\"odinger functional boundary conditions.\nNumerical simulations in the quenched approximation at parameters in the light\nquark mass region demonstrate that a performance gain of a factor $\\sim$ 1.5\nover even-odd preconditioning can be achieved."
    },
    {
        "anchor": "String tension in gonihedric 3D Ising models: For the 3D gonihedric Ising models defined by Savvidy and Wegner the bare\nstring tension is zero and the energy of a spin interface depends only on the\nnumber of bends and self-intersections, in antithesis to the standard\nnearest-neighbour 3D Ising action. When the parameter kappa weighting the\nself-intersections is small the model has a first order transition and when it\nis larger the transition is continuous.\n  In this paper we investigate the scaling of the renormalized string tension,\nwhich is entirely generated by fluctuations, using Monte Carlo simulations This\nallows us to obtain an estimate for the critical exponents alpha and nu using\nboth finite-size-scaling and data collapse for the scaling function.",
        "positive": "Numerical Quantum Field Theory on the Continuum and a New Look at\n  Perturbation Theory: The Source Galerkin method finds approximate solutions to the functional\ndifferential equations of field theories in the presence of external sources.\nWhile developing this process, it was recognized that approximations of the\nspectral representations of the Green's functions by Sinc function expansions\nare an extremely powerful calculative tool. Specifically, this understanding\nmakes it not only possible to apply the Source Galerkin method to higher\ndimensional field theories, but also leads to a new approach to perturbation\ntheory calculations in scalar and fermionic field theories. This report\nsummarizes the methodologies for solving quantum field theories with the Source\nGalerkin method and for performing perturbation theory calculations using Sinc\napproximations."
    },
    {
        "anchor": "Heavy-heavy current improvement for calculation of $\\bar{B}\\rightarrow\n  D^{(*)}\\ell \\bar\u03bd$ semi-leptonic form factors using the Oktay-Kronfeld\n  action: Lattice calculations of the form factors for $\\bar{B}\\to\nD^{(*)}\\ell\\bar{\\nu}$ decays can be used to extract the CKM matrix element\n$|V_{cb}|$. The Oktay-Kronfeld action is a highly improved version of the\nFermilab action, which systematically reduces heavy quark discretization\neffects through $\\mathcal{O}(\\lambda^3)$ in HQET power counting, for\nheavy-light meson quantities. To calculate $\\bar{B}\\rightarrow D^{(*)}\\ell\n\\bar{\\nu}$ semi-leptonic form factors using Oktay-Kronfeld heavy quarks, we\nneed to improve the heavy quark currents to the same level. We report our\nprogress in calculating the improvement coefficients for currents composed of\nbottom and charm quarks. Our results presented in this paper are preliminary.",
        "positive": "The $K\\to(\u03c0\u03c0)_{I=2}$ Decay Amplitude from Lattice QCD: We report on the first realistic \\emph{ab initio} calculation of a hadronic\nweak decay, that of the amplitude $A_2$ for a kaon to decay into two \\pi-mesons\nwith isospin 2. We find Re$A_2=(1.436\\pm 0.063_{\\textrm{stat}}\\pm\n0.258_{\\textrm{syst}})\\,10^{-8}\\,\\textrm{GeV}$ in good agreement with the\nexperimental result and for the hitherto unknown imaginary part we find\n{Im}$\\,A_2=-(6.83 \\pm 0.51_{\\textrm{stat}} \\pm\n1.30_{\\textrm{syst}})\\,10^{-13}\\,{\\rm GeV}$. Moreover combining our result for\nIm\\,$A_2$ with experimental values of Re\\,$A_2$, Re\\,$A_0$ and\n$\\epsilon^\\prime/\\epsilon$, we obtain the following value for the unknown ratio\nIm\\,$A_0$/Re\\,$A_0$ within the Standard Model:\n$\\mathrm{Im}\\,A_0/\\mathrm{Re}\\,A_0=-1.63(19)_{\\mathrm{stat}}(20)_{\\mathrm{syst}}\\times10^{-4}$.\nOne consequence of these results is that the contribution from Im\\,$A_2$ to the\ndirect CP violation parameter $\\epsilon^{\\prime}$ (the so-called Electroweak\nPenguin, EWP, contribution) is Re$(\\epsilon^\\prime/\\epsilon)_{\\mathrm{EWP}} =\n-(6.52 \\pm 0.49_{\\textrm{stat}} \\pm 1.24_{\\textrm{syst}}) \\times 10^{-4}$. We\nexplain why this calculation of $A_2$ represents a major milestone for lattice\nQCD and discuss the exciting prospects for a full quantitative understanding of\nCP-violation in kaon decays."
    },
    {
        "anchor": "Grid on QPACE 4: In 2020 we deployed QPACE 4, which features 64 Fujitsu A64FX model FX700\nprocessors interconnected by InfiniBand EDR. QPACE 4 runs an open-source\nsoftware stack. For Lattice QCD simulations we ported the Grid LQCD framework\nto support the ARM Scalable Vector Extension (SVE). In this contribution we\ndiscuss our SVE port of Grid, the status of SVE compilers and the performance\nof Grid. We also present the benefits of an alternative data layout of complex\nnumbers for the Domain Wall operator.",
        "positive": "$V_{ud}$ radiative corrections with lattice input: We will describe several pioneering efforts in the study of electromagnetic\nradiative corrections to semileptonic decay processes, with particular emphasis\non the role of lattice QCD. These studies are essential for the precise\nextraction of the matrix element $V_{ud}$ from beta decays of pion, free\nneutron and $J^P=0^+$ nuclei, and are crucial to address several\nrecently-emerged anomalies involving $V_{ud}$ and $V_{us}$, which may provide\nhints for physics beyond the Standard Model."
    },
    {
        "anchor": "Spectral reconstruction in SU(4) gauge theory with fermions in multiple\n  representations: The naturalness problem in the Higgs sector finds a popular solution in\ncomposite Higgs models. In such theories the Higgs boson emerges as the\npseudo-Nambu-Goldstone boson associated with the breaking of a global symmetry\nrealised in a new, strongly interacting sector. We address a model arising in\nthis context, a SU(4) gauge theory with fermions in two distinct\nrepresentations. We present a novel lattice study of this theory, in which we\naddress the non-perturbative reconstruction of spectral densities from lattice\ncorrelators.",
        "positive": "Open charm mesons at nonzero temperature: results in the hadronic phase\n  from lattice QCD: We study what happens to D and D_s mesons as the temperature increases, using\nlattice QCD simulations with N_f=2+1 dynamical flavours on anistropic lattices.\nWe have access to five temperatures in the hadronic phase. Using the determined\ngroundstate mass at the lowest temperature, we investigate the effect of rising\ntemperature by analysing ratios of mesonic correlators, without the need for\nfurther fitting or spectral reconstruction. In the pseudoscalar and vector\nchannels, we demonstrate that temperature effects are at the percent level and\ncan be captured by a reduction of the groundstate mass as the thermal crossover\nis approached. In the axial-vector and scalar channels on the other hand,\ntemperature effects are prominent throughout the hadronic phase."
    },
    {
        "anchor": "Nucleon Structure using lattice QCD: A review of recent nucleon structure calculations within lattice QCD is\npresented. The nucleon excited states, the axial charge, the isovector momentum\nfraction and helicity distribution are discussed, assessing the methods applied\nfor their study, including approaches to evaluate the disconnected\ncontributions. Results on the spin carried by the quarks in the nucleon are\nalso presented.",
        "positive": "Fitting two nucleons inside a box: exponentially suppressed corrections\n  to the Luscher's formula: Scattering observables can be computed in lattice field theory by measuring\nthe volume dependence of energy levels of two particle states. The dominant\nvolume dependence, proportional to inverse powers of the volume, is determined\nby the phase shifts. This universal relation (\\Lu's formula) between energy\nlevels and phase shifts is distorted by corrections which, in the large volume\nlimit, are exponentially suppressed. They may be sizable, however, for the\nvolumes used in practice and they set a limit on how small the lattice can be\nin these studies. We estimate these corrections, mostly in the case of two\nnucleons. Qualitatively, we find that the exponentially suppressed corrections\nare proportional to the {\\it square} of the potential (or to terms suppressed\nin the chiral expansion) and the effect due to pions going ``around the world''\nvanishes. Quantitatively, the size of the lattice should be greater than\n$\\approx(5 {fm})^3$ in order to keep finite volume corrections to the phase\nless than $1^\\circ$ for realistic pion mass."
    },
    {
        "anchor": "The bottomonium spectrum from lattice QCD with 2+1 flavors of domain\n  wall fermions: Recently, realistic lattice QCD calculations with 2+1 flavors of domain wall\nfermions and the Iwasaki gauge action have been performed by the RBC and UKQCD\ncollaborations. Here, results for the bottomonium spectrum computed on their\ngauge configurations of size 24^3x64 with a lattice spacing of approximately\n0.11 fm and four different values for the light quark mass are presented.\nImproved lattice NRQCD is used to treat the b quarks inside the bottomonium.\nThe results for the radial and orbital energy splittings are found to be in\ngood agreement with experimental measurements, indicating that systematic\nerrors are small. The calculation of the Upsilon(2S)-Upsilon(1S) energy\nsplitting provides an independent determination of the lattice spacing. For the\nmost physical ensemble it is found to be a^{-1}=1.740(25)(19) GeV, where the\nfirst error is statistical/fitting and the second error is an estimate of the\nsystematic errors due to the lattice NRQCD action.",
        "positive": "Can a light Higgs impostor hide in composite gauge models?: The frequently discussed strongly interacting gauge theory with a fermion\nflavor doublet in the two-index symmetric (sextet) representation of the SU(3)\ncolor gauge group is investigated. In previous studies the chiral condensate\nand the mass spectrum were shown to be consistent with chiral symmetry breaking\n($\\chi$SB) at vanishing fermion mass. The recently reported $\\beta$-function is\nnot inconsistent with this observation, suggesting that the model is very close\nto the conformal window and a light \"Higgs impostor\" could emerge as a\ncomposite state. In this work we describe the methodology and preliminary\nresults of studying the emergence of the light composite scalar with $0^{++}$\nquantum numbers."
    },
    {
        "anchor": "On Nonexistence of Magnetic Charge in Pure Yang-Mills Theories: We prove that magnetic charge does not exist as a physical observable on the\nphysical Hilbert space of the pure SU(2) gauge theory. The abelian magnetic\nmonopoles seen in lattice simulations are then interpreted as artifacts of\ngauge fixing. The apparent physical scaling properties of the monopole density\nin the continuum limit observed on the lattice are attributed to the correct\nscaling properties of physical objects - magnetic vortices, as first argued by\nGreensite et. al. We can show that a local gauge transformation of a certain\ntype can \" create\" abelian monopole-antimonopole pairs along magnetic vortices.\nThis gauge transformation exists in pure SU(N) gauge theory at any $N$.",
        "positive": "Critical exponents in abelian projected $SU(2)$ QCD: The critical properties of the abelian Polyakov loop and the Polyakov loop in\nterms of Dirac string are studied in finite temperature abelian projected\n$SU(2)$ QCD. The critical point and the critical exponents are determined from\neach Polyakov loop in the maximally abelian gauge using the finite-size scaling\nanalyses. Those critical points and exponents are in good agreement with those\nfrom non-abelian Polyakov loops."
    },
    {
        "anchor": "Combining Quark and Link Smearing to Improve Extended Baryon Operators: The effects of Gaussian quark-field smearing and analytic stout-link smearing\non the correlations of gauge-invariant extended baryon operators are studied.\nGaussian quark-field smearing substantially reduces contributions from the\nshort wavelength modes of the theory, while stout-link smearing significantly\nreduces the noise from the stochastic evaluations. The use of gauge-link\nsmearing is shown to be crucial for baryon operators constructed of\ncovariantly-displaced quark fields. Preferred smearing parameters are\ndetermined for a lattice spacing a_s ~ 0.1 fm.",
        "positive": "Propagators and topology: Two popular perspectives on the non-perturbative domain of Yang-Mills\ntheories are either in terms of the gluons themselves or in terms of collective\ngluonic excitations, i.e. topological excitations. If both views are correct,\nthen they are only two different representations of the same underlying\nphysics. One possibility to investigate this connection is by the determination\nof gluon correlation functions in topological background fields, as created by\nthe smearing of lattice configurations. This is performed here for the minimal\nLandau gauge gluon propagator, ghost propagator, and running coupling, both in\nmomentum and position space for SU(2) Yang-Mills theory. The results show that\nthe salient low-momentum features of the propagators are qualitatively retained\nunder smearing at sufficiently small momenta, in agreement with an equivalence\nof both perspectives. However, the mid-momentum behavior is significantly\naffected. These results are also relevant for the construction of truncations\nin functional methods, as they provide hints on necessary properties to be\nretained in truncations."
    },
    {
        "anchor": "On a development of the phenomenological renormalization group: We propose a modification of the Nightingale renormalization group for\nlattice spin and gauge models by combining it with the cluster decimation\napproximation. Essential ingredients of our approach are: 1) exact calculation\nof the partition and correlation function on a finite lattice strip; 2)\npreservation of the mass gap or the second moment correlation length, computed\nin the infinite strip length limit, on each decimation step. The method is\napplied for studying general two and three dimensional Z(N) models. A perfect\nagreement with exact results (whenever available) is found. An extension of the\nmethod to models with a continuous symmetry is briefly discussed.",
        "positive": "Quantum Interactions Between Non-Perturbative Vacuum Fields: We develop an approach to investigate the non-perturbative dynamics of\nquantum field theories, in which specific vacuum field fluctuations are treated\nas the low-energy dynamical degrees of freedom, while all other vacuum field\nconfigurations are explicitly integrated out from the path integral. We show\nhow to compute the effective interaction between the vacuum field degrees of\nfreedom both perturbatively (using stochastic perturbation theory) and fully\nnon-perturbatively (using lattice field theory simulations). The present\napproach holds to all orders in the couplings and does not rely on the\nsemi-classical approximation."
    },
    {
        "anchor": "Probing the chiral weak Hamiltonian at finite volumes: Non-leptonic kaon decays are often described through an effective chiral weak\nHamiltonian, whose couplings (\"low-energy constants\") encode all\nnon-perturbative QCD physics. It has recently been suggested that these\nlow-energy constants could be determined at finite volumes by matching the\nnon-perturbatively measured three-point correlation functions between the weak\nHamiltonian and two left-handed flavour currents, to analytic predictions\nfollowing from chiral perturbation theory. Here we complete the analytic side\nin two respects: by inspecting how small (\"epsilon-regime\") and intermediate or\nlarge (\"p-regime\") quark masses connect to each other, and by including in the\ndiscussion the two leading Delta I = 1/2 operators. We show that the\nepsilon-regime offers a straightforward strategy for disentangling the\ncoefficients of the Delta I = 1/2 operators, and that in the p-regime\nfinite-volume effects are significant in these observables once the\npseudoscalar mass M and the box length L are in the regime ML \\lsim 5.0.",
        "positive": "Calculating the $\u03c1$ radiative decay width with lattice QCD: We present the results of our lattice QCD study of the $\\pi\\gamma\\to\\pi\\pi$\nprocess, where the $\\rho$ resonance appears as an enhancement in the transition\namplitude. We use $N_f=2+1$ clover fermions on a lattice of $L=3.6$ fm and a\npion mass of $320$ MeV. Using a combination of forward, stochastic, and\nsequential propagators, we calculate the two-point and three-point functions\nthat allow us to determine the $\\pi\\gamma\\to\\pi\\pi$ matrix elements for several\nvalues of the invariant mass $s$ and momentum transfer $q^2$. To fit the $q^2$\nand $s$ dependence of the $\\pi\\gamma\\to\\pi\\pi$ amplitude, we explore a set of\ngeneral parametrizations based on a Taylor expansion. By analytic continuation\nto the complex pole corresponding to the $\\rho$ resonance, we determine the\nresonant form factors and calculate the radiative decay width of the $\\rho$."
    },
    {
        "anchor": "Non-perturbative quark mass dependence in the heavy-light sector of\n  two-flavour QCD: We present preliminary results of the non-perturbative heavy quark mass\ndependence of heavy-light meson observables in the continuum limit of\nfinite-volume two-flavour lattice QCD. These observables, which are derived\nfrom heavy-light Schroedinger functional correlation functions and computed\nover a range of renormalization group invariant heavy quark masses from the\ncharm to beyond the bottom region, allow for a quantitative comparison with the\npredictions of HQET and are of practical relevance for solving renormalization\nproblems in HQET non-perturbatively by a matching to QCD in finite volume.",
        "positive": "Gonihedric Ising Actions: We discuss a generalized Ising action containing nearest neighbour, next to\nnearest neighbour and plaquette terms that has been suggested as a potential\nstring worldsheet discretization on cubic lattices by Savvidy and Wegner. This\ndisplays both first and second order transitions depending on the value of a\n``self-intersection'' coupling as well as possessing a novel semi-global\nsymmetry."
    },
    {
        "anchor": "Applied lattice gauge calculations: diquark content of the nucleon: As an example of an application of lattice QCD we describe a computation of\nfour-quark operators in the nucleon. The results are interpreted in a diquark\nlanguage.",
        "positive": "Pion spectrum using improved staggered fermions: We present results for the pion multiplet spectrum calculated using both\nunimproved staggered fermions and improved HYP-smeared staggered fermions. In\nthe case of unimproved staggered fermions, we observe (consistent with previous\nwork) that ${\\cal O}(a^2)$ taste symmetry breaking effects are large and\ncomparable to the $\\approx {\\cal O}(p^2)$ contributions to their masses. Higher\norder ${\\cal O}(a^2 p^2)$ effects are also substantial enough to be seen. For\nHYP-smeared staggered fermions, we find that taste breaking is much reduced.\nThe ${\\cal O}(a^2)$ effects are observable, but are noticeably smaller than\nthose obtained with AsqTad-improved staggered fermions, and much smaller than\nthose obtained using unimproved staggered fermions, while ${\\cal O}(a^2 p^2)$\neffects are suppressed to such a level that we cannot observe them given our\nstatistical errors. From this numerical study, we conclude that HYP staggered\nfermions are significantly better that AsqTad fermions from the perspective of\ntaste symmetry breaking."
    },
    {
        "anchor": "Glueballs from Improved Lattice Actions: The low-lying glueball masses and the hadronic scale $r_0$ are computed in\nlattice SU(3) gauge theory with the aim of establishing the effectiveness of\nthe improved action approach in removing finite-spacing artifacts. The use of\nanisotropic lattices in which the temporal spacing is much smaller than that in\nthe spatial directions allows much more efficient glueball mass measurements.",
        "positive": "Independent Operators at Different Dimension: To apply lattice QCD in the calculation of glueball spectrum it is needed\nfirstly to know associated operators acting on vacuum. We show how to find all\nthe independent representations and operators, of group $SO(3)^{PC}$ at\ndifferent dimension, since the work is not trivial. Then, we decompose these\nrepresentation into irreducible representation of $O^{PC}$ group, which are\nlisted in the note. At last we argue that $f_J(2220)$ and $g_T$ states can not\nbe tensor glueball simultaneously."
    },
    {
        "anchor": "Lattice calculation of low energy constants with Ginsparg-Wilson type\n  fermions: We present a quenched lattice calculation of low energy constants using the\nchirally improved Dirac operator. Several lattice sizes at different lattice\nspacings are studied. We systematically compare various methods for computing\nthese quantities, using pseudoscalar and axial vector correlators. We find\nconsistent results for the different approaches, giving rise to f_\\pi =\n96(2)(4) MeV, f_K = 106(1)(8) MeV, f_K/f_\\pi=1.11(1)(2), Sigma= -(286(4)(31)\nMeV)^3, the average light quark mass m = 4.1(2.4) MeV and m_s = 101(8) MeV.",
        "positive": "Magnetic Monopoles and the Dual London Equation in SU(3) Lattice Gauge\n  Theory: We propose a method for the determination of magnetic monopole currents in\nnon-Abelian gauge theories which does not need a projection to Abelian degrees\nof freedom. With this definition we are able to determine the distribution of\nmagnetic currents and electric fields for the gluonic flux tube between a pair\nof static charges. Further we check the validity of the Gauss law and the dual\nLondon equation in a gauge invariant formulation."
    },
    {
        "anchor": "$B_s\\to D_s^{(*)}l\u03bd$ Form Factors with Heavy HISQ Quarks: We present progress on an ongoing calculation of the $B_s\\to D_s^{(*)} l \\nu$\nform factors calculated on the $n_f=2+1+1$ MILC ensembles and using the Highly\nImproved Staggered Quark action for all valence quarks. We perform the\ncalculation at a range of $b$ quark masses (and lattice spacings) so that we\ncan extrapolate to the physical $b$-quark mass.",
        "positive": "Towards a non-perturbative computation of the RGI strange quark mass\n  with two dynamical flavors: The non-perturbative running of the quark mass in the Schroedinger functional\nscheme is computed over a large energy range (covering scales differing by two\norders of magnitude). This allows to relate lattice estimates of the running\nquark mass to the renormalization group invariant mass. The result is used in a\npreliminary computation of the strange quark mass in the theory with two\nflavors of non-perturbatively improved Wilson quarks. A more detailed\ndiscussion of the calculation can be found in [1]."
    },
    {
        "anchor": "Numerical Evaluation of the Bose-Ghost Propagator in Minimal Landau\n  Gauge on the Lattice: We present numerical details of the evaluation of the so-called Bose-ghost\npropagator in lattice minimal Landau gauge, for the SU(2) case in four\nEuclidean dimensions. This quantity has been proposed as a carrier of the\nconfining force in the Gribov-Zwanziger approach and, as such, its infrared\nbehavior could be relevant for the understanding of color confinement in\nYang-Mills theories. Also, its nonzero value can be interpreted as direct\nevidence of BRST-symmetry breaking, which is induced when restricting the\nfunctional measure to the first Gribov region Omega. Our simulations are done\nfor lattice volumes up to 120^4 and for physical lattice extents up to 13.5 fm.\nWe investigate the infinite-volume and continuum limits.",
        "positive": "New fixed point action for SU(3) lattice gauge theory: We present a new fixed point action for SU(3) lattice gauge theory, which has\n--- compared to earlier published fixed point actions --- shorter interaction\nrange and smaller violations of rotational symmetry in the static\n$q\\bar{q}$-potential even at shortest distances."
    },
    {
        "anchor": "Semileptonic B Decays with Nf=2+1 Dynamical Quarks: Semileptonic, B --> pi l,nu, decays are studied on the MILC dynamical\nconfigurations using NRQCD heavy and Asqtad light quarks. We work with light\nvalence quark masses ranging between m_s and m_s/8. Preliminary simple linear\nchiral extrapolations have been carried out for form factors f_para and f_perp\nat fixed E_pi. The chirally extrapolated results for the form factors f_+(q^2)\nand f_0(q^2) are then fit to the Becirevic-Kaidalov (BK) ansatz. Preliminary\nestimates of the CKM matrix element |V_{ub}| are presented based on the\nrecently published branching fractions for B exclusive semileptonic decays by\nthe CLEO collaboration.",
        "positive": "Hidden charm molecules in a Finite Volume: In the present paper we address the interaction of charmed mesons in hidden\ncharm channels in a finite box. We use the interaction from a recent model\nbased on heavy quark spin symmetry that predicts molecules of hidden charm in\nthe infinite volume. The energy levels in the box are generated within this\nmodel, and several methods for the analysis of these levels (\"inverse problem\")\nare investigated."
    },
    {
        "anchor": "Linear Covariant Gauges on the Lattice: Linear covariant gauges, such as Feynman gauge, are very useful in\nperturbative calculations. Their nonperturbative formulation is, however,\nhighly non-trivial. In particular, it is a challenge to define linear covariant\ngauges on a lattice. We consider a class of gauges in lattice gauge theory that\ncoincides with the perturbative definition of linear covariant gauges in the\nformal continuum limit. The corresponding gauge-fixing procedure is described\nand analyzed in detail, with an application to the pure SU(2) case. In\naddition, results for the gluon propagator in the two-dimensional case are\ngiven.",
        "positive": "Fuzzy Gauge Theory for Quantum Computers: Continuous gauge theories, because of their bosonic degrees of freedom, have\nan infinite-dimensional local Hilbert space. Encoding these degrees of freedom\non qubit-based hardware demands some sort of ``qubitization'' scheme, where one\napproximates the behavior of a theory while using only finitely many degrees of\nfreedom. We propose a novel qubitization strategy for gauge theories, called\n``fuzzy gauge theory,'' building on the success of the fuzzy $\\sigma$-model in\nearlier work. We provide arguments that the fuzzy gauge theory lies in the same\nuniversality class as regular gauge theory, in which case its use would obviate\nthe need of any further limit besides the usual spatial continuum limit.\nFurthermore, we demonstrate that these models are relatively resource-efficient\nfor quantum simulations."
    },
    {
        "anchor": "CP-violating Dashen phase transition in the two-flavor Schwinger model:\n  a study with matrix product states: We numerically study the Hamiltonian lattice formulation of the two-flavor\nSchwinger model using matrix product states. Keeping the mass of the first\nflavor at a fixed positive value, we tune the mass of the second flavor through\na range of negative values, thus exploring a regime where conventional Monte\nCarlo methods suffer from the sign problem and may run into instabilities due\nto zero modes. Our results indicate a phase transition at the point where the\nabsolute value of the second flavor mass approaches the first flavor mass. The\nphase transition is accompanied by the formation of a fermion condensate, a\nsteep drop of the average electric field, and a peak in the bipartite\nentanglement entropy. Our data hints at a second order transition, which is the\n1+1D analog of the CP-violating Dashen phase transition in QCD.",
        "positive": "Lattice study of the chiral magnetic effect in a chirally imbalanced\n  matter: We investigate the chiral magnetic effect by lattice QCD with a chiral\nchemical potential. In a chirally imbalanced matter, we obtain a finite induced\ncurrent along an external magnetic field. We analyze the dependence on the\nlattice spacing, the temperature, the spatial volume, and the fermion mass. The\npresent result indicates that the continuum limit is important for the\nquantitative argument of the strength of the induced current."
    },
    {
        "anchor": "Calculating the chiral condensate diagrammatically at strong coupling: We calculate the chiral condensate of QCD at infinite coupling as a function\nof the number of fundamental fermion flavours using a lattice diagrammatic\napproach inspired by recent work of Tomboulis, and other work from the 80's. We\noutline the approach where the diagrams are formed by combining a truncated\nnumber of sub-diagram types in all possible ways. Our results show evidence of\nconvergence and agreement with simulation results at small Nf. However,\ncontrary to recent simulation results, we do not observe a transition at a\ncritical value of Nf. We further present preliminary results for the chiral\ncondensate of QCD with symmetric or adjoint representation fermions at infinite\ncoupling as a function of Nf for Nc = 3. In general, there are sources of error\nin this approach associated with miscounting of overlapping diagrams, and\nover-counting of diagrams due to symmetries. These are further elaborated upon\nin a longer paper.",
        "positive": "A Generalized Maximal Abelian Gauge in SU(3) Lattice Gauge Theory: We introduce a generalized Maximum Abelian Gauge (MAG). We work with this new\ngauge on 12^4 lattices for beta=5.7,5.8 and 16^4 lattices for beta=5.9,6.0. We\nalso introduce a form of abelian projection related to the generalized MAG. We\nmeasure U(1)xU(1) wilson loops and single color magnetic current densities."
    },
    {
        "anchor": "The quark contents of the nucleon and their implication for dark matter\n  search: We present results concerning the light and strange quark contents of the\nnucleon using $N_f=2+1+1$ flavours of maximally twisted mass fermions. The\ncorresponding $\\sigma$-terms are casting light on the origin of the nucleon\nmass and their values are important to interpret experimental data from direct\ndark matter searches. We discuss our strategy to estimate systematic\nuncertainties arising in our computations. Our preliminary results for the\n$\\sigma-$terms read $\\sigma_{\\pi N} = 37(2.6)(24.7) \\mev$ and\n$\\sigma_s=28(8)(10) \\mev$. We present our recent final analysis of the $y_N$\nparameter and found $y_N=0.135(46)$ including\nsystematics\\cite{Alexandrou:2013nda}.",
        "positive": "Bottom hadron mass splittings in the static limit from 2+1 flavour\n  lattice QCD: Dynamical 2+1 flavour lattice QCD is used to calculate the splittings between\nthe masses of mesons and baryons containing a single static heavy quark and\ndomain-wall light and strange quarks. Our calculations are based on the\ndynamical domain-wall gauge field configurations generated by the RBC and UKQCD\ncollaborations at a spatial volume of (2.7 fm)^3 and a range of quark masses\nwith a lightest value corresponding to a (partially-quenched) pion mass of 275\nMeV. When extrapolated to the physical values of the light quark masses, the\nresults of our calculations are generally in good agreement with experimental\ndeterminations in the bottom sector. However, the static limit splittings\nbetween the Omega_b^- baryon and other bottom hadrons tend to slightly\nunderestimate those obtained using the recent D-zero measurement of the\nOmega_b^-."
    },
    {
        "anchor": "$3$--Dimensional Approach to Hot Electroweak Matter for $M_{Higgs} \\leq\n  70$ GeV: We study the electroweak phase transition by lattice simulations of an\neffective 3-dimensional theory, for a Higgs mass of about $70$ GeV. Exploiting\na variant of the equal weight criterion of phase equilibrium, we obtain\ntransition temperature, latent heat and surface tension and compare with $M_H\n\\approx 35$ GeV. For the symmetric phase, bound state masses and the static\nforce are determined and compared with results for pure $SU(2)$ theory.",
        "positive": "The upper right corner of the Columbia plot with staggered fermions: QCD with heavy dynamical quarks exhibits a first order thermal transition\nwhich is driven by the spontaneous breaking of the global $\\mathcal{Z}_3$\ncenter symmetry. Decreasing the quark masses weakens the transition until the\ncorresponding latent heat vanishes at the critical mass. We explore the heavy\nmass region with three flavors of staggered quarks and analyze the Polyakov\nloop and its moments in a finite volume scaling study. We calculate the heavy\ncritical mass in the three flavor theory in the infinite volume limit for\n$N_t=8$."
    },
    {
        "anchor": "Charm and bottom heavy baryon mass spectrum from lattice QCD with 2+1: We present results for the mass spectrum of charm and bottom heavy baryons,\nusing MILC coarse lattice configurations with 2+1 flavors. Clover heavy quark\npropagators with the Fermilab interpretation and improved staggered light quark\npropagators are used to construct two point functions with local operators for\ndifferent flavor and spin states.",
        "positive": "Heavy-light decay constant at the 1/m order of HQET: Following the strategy developed by the ALPHA collaboration, we present a\nmethod to compute non-perturbatively the decay constant of a heavy-light meson\nin HQET including the 1/m corrections. We start by a matching between HQET and\nQCD in a small volume to determine the parameters of the effective theory\nnon-perturbatively. Observables in the effective theory are then evolved to\nlarger volumes. In two steps a large enough volume is reached to determine the\nphysical decay constant. Some preliminary results in the quenched approximation\nare shown."
    },
    {
        "anchor": "Exact Ward-Takahashi identity for the lattice N=1 Wess-Zumino model: The lattice Wess-Zumino model written in terms of the Ginsparg-Wilson\nrelation is invariant under a generalized supersymmetry transformation which is\ndetermined by an iterative procedure in the coupling constant. By studying the\nassociated Ward-Takahashi identity up to order $g^2$ we show that this lattice\nsupersymmetry automatically leads to restoration of continuum supersymmetry\nwithout fine tuning. In particular, the scalar and fermion renormalization wave\nfunctions coincide.",
        "positive": "Adaptive Aggregation-based Domain Decomposition Multigrid for Twisted\n  Mass Fermions: The Adaptive Aggregation-based Domain Decomposition Multigrid method\n(arXiv:1303.1377) is extended for two degenerate flavors of twisted mass\nfermions. By fine-tuning the parameters we achieve a speed-up of the order of\nhundred times compared to the conjugate gradient algorithm for the physical\nvalue of the pion mass. A thorough analysis of the aggregation parameters is\npresented, which provides a novel insight into multigrid methods for lattice\nQCD independently of the fermion discretization."
    },
    {
        "anchor": "Supersphere non-linear sigma model on the lattice: Two-dimensional $O(N)$ non-linear sigma models are exactly solvable theories\nand have many applications, from statistical mechanics to their use as QCD toy\nmodels. We consider a supersymmetric extension, the non-linear sigma model on\nthe supersphere~$S^{N+2m-1|2m}\\equiv \\frac{OSP(N+2m|2m)}{OSP(N+2m-1|2m)}$. We\nbriefly describe its renormalization properties and lattice discretization, and\npresent a strategy for numerical simulations together with some preliminary\nnumerical results.",
        "positive": "Perturbative determination of $c_{SW}$ for plaquette and Symanzik gauge\n  action and stout link clover fermions: Using plaquette and Symanzik improved gauge action and stout link clover\nfermions we determine the improvement coefficient $c_{SW}$ in one-loop lattice\nperturbation theory from the off-shell quark-quark-gluon three-point function.\nIn addition, we compute the coefficients needed for the most general form of\nquark field improvement and present the one-loop result for the critical\nhopping parameter $\\kappa_c$. We discuss mean field improvement for $c_{SW}$\nand $\\kappa_c$ and the choice of the mean field coupling for the actions we\nhave considered."
    },
    {
        "anchor": "First Lattice Study of Ghost Propagators in SU(2) and SU(3) Gauge\n  Theories: We present a numerical study of the ghost propagators in Landau gauge for\nSU(2) and SU(3) gauge theories at $\\beta$=2.7 and $\\beta$=6.0, respectively.\nAnalyzing different lattice sizes up to $32^4$, we find small finite size\neffects. Down to the smallest available momenta, we observe no evidence for\ndipole behaviour of the ghost propagators.",
        "positive": "Speeding up Fermionic Lattice Calculations with Photonic Accelerated\n  Inverters: Lattice field theory (LFT) is the standard non-perturbative method to perform\nnumerical calculations of quantum field theory. However, the typical bottleneck\nof fermionic lattice calculations is the inversion of the Dirac matrix. This\ninversion is solved by iterative methods, like the conjugate gradient\nalgorithm, where matrix-vector multiplications (MVMs) are the main operation.\nPhotonic integrated circuits excel in performing quick and energy-efficient\nMVMs, but at the same time, they are known to have low accuracy. This can be\novercome by using mixed precision methods. In this paper, we explore the idea\nof using photonic technology to fulfil the demand for computational power of\nfermionic lattice calculations. These methods have the potential to reduce\ncomputation costs by one order of magnitude. Because of the hybrid nature of\nthese methods, we call these 'photonic accelerated inverters (PAIs)'."
    },
    {
        "anchor": "Toward dense QCD in quantum computers: Lattice QCD at nonzero baryon density is a big challenge in hadron physics.\nIn this presentation, I discuss the quantum computation of lattice gauge theory\nat nonzero density. I show some benchmark results of the Schwinger model\nobtained by the quantum adiabatic algorithm and the quantum variational\nalgorithm.",
        "positive": "Computational efficiency of staggered Wilson fermions: A first look: Results on the computational efficiency of 2-flavor staggered Wilson fermions\ncompared to usual Wilson fermions in a quenched lattice QCD simulation on\n$16^3\\times32$ lattice at $\\beta=6$ are reported. We compare the cost of\ninverting the Dirac matrix on a source by the conjugate gradient (CG) method\nfor both of these fermion formulations, at the same pion masses, and without\npreconditioning. We find that the number of CG iterations required for\nconvergence, averaged over the ensemble, is less by a factor of almost 2 for\nstaggered Wilson fermions, with only a mild dependence on the pion mass. We\nalso compute the condition number of the fermion matrix and find that it is\nless by a factor of 4 for staggered Wilson fermions. The cost per CG iteration,\ndominated by the cost of matrix-vector multiplication for the Dirac matrix, is\nknown from previous work to be less by a factor 2-3 for staggered Wilson\ncompared to usual Wilson fermions. Thus we conclude that staggered Wilson\nfermions are 4-6 times cheaper for inverting the Dirac matrix on a source in\nthe quenched backgrounds of our study."
    },
    {
        "anchor": "The Method of Recursive Counting: Can One Go Further?: After a short review of the Method of Recursive Counting we introduce a\ngeneral algebraic description of recursive lattice building. This provides a\nrigorous framework for discussion of method's limitations.",
        "positive": "Properties of Abelian Monopoles in SU(2) Lattice Gluodynamics: We discuss some properties of abelian monopoles in the Maximal Abelian\nprojection of the SU(2) lattice gluodynamics. We show that in the maximal\nabelian projection abelian monopoles carry fluctuating electric charge and that\nthe monopole currents are correlated with the magnetic and the electric parts\nof the SU(2) action density."
    },
    {
        "anchor": "Krylov subspace methods and the sign function: multishifts and deflation\n  in the non-Hermitian case: Rational approximations of the matrix sign function lead to multishift\nmethods. For non-Hermitian matrices long recurrences can cause storage\nproblems, which can be circumvented with restarts. Together with deflation we\nobtain efficient iterative methods, as we show in numerical experiments for the\noverlap Dirac operator at non-vanishing quark chemical potential for lattices\nup to size 10^4.",
        "positive": "Improved study of the $\u03b2$-function of $SU(3)$ gauge theory with $N_f\n  = 10 $ massless domain-wall fermions: I perform an improved study of the $\\beta$-function of $ SU(3) $ lattice\ngauge theory with $N_f=10$ massless optimal domain-wall fermions in the\nfundamental representation, which serves as a check to what extent the scenario\nin the previous work [arXiv:1603.08854; Proc. Sci. LATTICE2016 (2017) 228] is\nvalid. In the finite-volume gradient flow scheme with $ c = \\sqrt{8t}/L = 0.3\n$, the renormalized couplings $g^2 (L,a) $ of four primary lattices ($ L/a = \\{\n8, 10, 12, 16 \\}$) are tuned (in $ 6/g_0^2 $) to the same $ g_c^2 $ with\nstatistical error less than $0.5 \\% $, in contrast to the previous work where $\ng^2(L,a) $ were obtained by the cubic-spline interpolation. Then the\nrenormalized couplings $ g^2(sL, a) $ of the scaled lattices ($ sL/a = \\{16,\n20, 24, 32\\} $ with $s=2$) are computed at the same $ 6/g_0^2 $ of the\ncorresponding primary lattices. Using the renormalized couplings of four\nlattice pairs $ (sL,L)/a = \\{ (16,8), (20,10), (24,12), (32,16) \\} $, the\nstep-scaling $\\beta$-function $ [g^2(sL,a) - g^2(L,a)]/\\ln (s^2) $ is computed\nand extrapolated to the continuum limit $ \\beta(s,g_c^2) $, as summarized in\nTable III. Based on the four data points of $ \\beta(s,g_c^2) $ at $ g_c^2 = \\{\n6.86(2), \\ 6.92(3), \\ 7.03(2), \\ 7.16(2) \\} $, I infer that the theory is\ninfrared near-conformal, or conformal with the fixed-point $ g_*^2 = 7.55(36)\n$. This corrects the scenario in the previous work with $ g_*^2 \\sim 7.0 $, and\nalso suggests that the interpolation method cannot give a reliable\ndetermination of the $\\beta$-function, especially in the regime close to the\ninfrared fixed-point."
    },
    {
        "anchor": "Large q expansion of the 2D q-states Potts model: We present a recursive method to calculate a large q expansion of the 2d\nq-states Potts model free energies based on the Fortuin-Kasteleyn\nrepresentation of the model. With this procedure, we compute directly the\nordered phase partition function up to order 10 in 1/sqrt{q}. The energy\ncumulants at the transition can be obtained with suitable resummation and come\nout large for q less or around 15. As a consequence, expansions of the free\nenergies around the transition temperature are useless for not large enough\nvalues of q. In particular the pure phase specific heats are predicted to be\nmuch larger, at q < 15, than the values extracted from current finite size\nscaling analysis of extrema, whereas they agree very well with recent values\nextracted at the transition point.",
        "positive": "Matrix elements and diquark correlations in quenched QCD with overlap\n  fermions: We present results for B_K and selected matrix elements for beyond the\nstandard model interactions obtained in quenched QCD with overlap fermions. We\nalso illustrate results on baryon wave-functions and diquark correlations\nwithin baryons in the Coulomb and Landau gauge."
    },
    {
        "anchor": "Proton Isovector Helicity Distribution on the Lattice at Physical Pion\n  Mass: We present a state-of-the-art calculation of the isovector quark helicity\nBjorken-$x$ distribution in the proton using lattice-QCD ensembles at the\nphysical pion mass. We compute quasi-distributions at proton momenta $P_z \\in\n\\{2.2, 2.6, 3.0\\}$~GeV on the lattice, and match them systematically to the\nphysical parton distribution using large-momentum effective theory (LaMET). We\nreach an unprecedented precision through high statistics in simulations,\nlarge-momentum proton matrix elements, and control of excited-state\ncontamination. The resulting distribution with combined statistical and\nsystematic errors is in agreement with the latest phenomenological analysis of\nthe spin-dependent experimental data; in particular, $\\Delta \\bar{u}(x)>\\Delta\n\\bar{d}(x)$.",
        "positive": "Chiral Symmetry Breaking on the Lattice: We review important aspects of QCD in the continuum and on the lattice and\ntake a look at the fate of its symmetries with an emphasis on chiral symmetry\nbreaking on the lattice."
    },
    {
        "anchor": "Spacelike Wilson Loops at Finite Temperature: In the high temperature phase of Yang-Mills theories, large spatial Wilson\nloops show area law behaviour with a string tension that grows with increasing\ntemperature. Within the framework of the commonly used string picture we use a\nlarge scale expansion, which allows us to determine the string tension from\nmeasurements of intermediate and symmetric Wilson loops.",
        "positive": "SU(2) Potentials from Large Lattices: We measure accurate values of the inter-quark potentials on a $48^{3}56$\nlattice with SU(2) pure gauge theory at $ \\beta =2.85$. The scale is set by\nextracting the string tension - we obtain ${\\sqrt K}a=0.063(3)$ at $\\beta\n=2.85.$ From a careful study of the small-$R$ potentials in the region 2 GeV $<\nR^{-1} < 5$ GeV, we extract a running coupling constant and estimate the scale\n$\\Lambda _{\\msbar} = 272(24)$ MeV."
    },
    {
        "anchor": "Quantum Computing for the Wess-Zumino Model: Future quantum computers will enable novel sign-problem-free studies of\ndynamical phenomena in non-perturbative quantum field theories, including\nreal-time evolution and spontaneous supersymmetry breaking. We are\ninvestigating applications of quantum computing to low-dimensional\nsupersymmetric lattice systems that can serve as testbeds for existing and\nnear-future quantum devices. Here we present initial results for the\n$\\mathcal{N} = 1$ Wess--Zumino model in 1+1 dimensions, building on our prior\nanalyses of 0+1-dimensional supersymmetric quantum mechanics. In addition to\nexploring supersymmetry breaking using the variational quantum eigensolver, we\nconsider the prospects for real-time evolution.",
        "positive": "Axial U(1) symmetry, topology, and Dirac spectra at high temperature in\n  $N_f=2$ lattice QCD: Using lattice QCD simulations with $N_f = 2$ dynamical fermions, we study the\naxial $U(1)$ symmetry, topological charge, and Dirac eigenvalue spectra in the\nhigh-temperature phase in which the chiral symmetry is restored. Our gauge\nensembles are generated with M\\\"obius domain-wall fermions, but the\nmeasurements such as susceptibilities are reweighted to those for the overlap\nfermions by using overlap/domain-wall reweighting technique. We find that the\n$U(1)_A$ and topological susceptibilities are strongly suppressed in the small\nquark mass region, which is related to the reduction of chiral-zero and\nlow-nonzero modes on the Dirac spectra. We also examine their volume\ndependence."
    },
    {
        "anchor": "Perturbative Renormalization of Lattice Bilinear Quark Operators: Our aim is to compute the lower moments of the unpolarized and polarized\ndeep-inelastic structure functions of the nucleon on the lattice. The\ntheoretical basis of the calculation is the operator product expansion. To\nconstruct operators with the appropriate continuum behavior out of the bare\nlattice operators one must absorb the effects of momentum scales far greater\nthan any physical scale into a renormalization of the operators. In this work\nwe compute the renormalization constants of all bilinear quark operators of\nleading twist and spin up to four. The calculation is done for Wilson fermions\nand in the quenched approximation where dynamical quark loops are neglected.",
        "positive": "N and N to Delta transition form factors from Lattice QCD: We present recent lattice QCD results on nucleon form factors and N to Delta\ntransition form factors. We predict the parity violating asymmetry in N to\nDelta and check the off-diagonal Goldberger-Treiman relation."
    },
    {
        "anchor": "Charm and beauty in the deconfined plasma from quenched lattice QCD: We present continuum extrapolated results of charmonium and bottomonium\ncorrelators in the vector channel at several temperatures below and above\n$T_c$. The continuum extrapolation jointly performed with the interpolations to\nhave physical values of $J/\\psi$ and $\\Upsilon$ masses in the confined phase is\nbased on calculations on several large quenched isotropic lattices using\nclover-improved Wilson valence fermions carrying different quark masses. The\nextrapolated lattice correlators are confronted with perturbation theory\nresults incorporating resummed thermal effects around the threshold from pNRQCD\nand vacuum asymptotics above the threshold. An additional transport peak is\nmodelled below the threshold allowing for an estimate of the diffusion\ncoefficients for charm and bottom quarks. We find that charmonium correlators\nin the vector channel can be well reproduced by perturbative spectral functions\nabove $T_c$ where no resonance peaks for $J/\\psi$ are needed at and above 1.1\n$T_c$, while for bottomonium correlators a resonance peak for $\\Upsilon$ is\nstill needed up to 1.5 $T_c$. By analyzing the transport contribution to the\ncorrelators we find that the drag coefficient of a charm quark is larger than\nthat of a bottom quark.",
        "positive": "Update on Nf=3 finite temperature QCD phase structure with Wilson-Clover\n  fermion action: We present an update of the finite temperature phase structure analysis for\nthree flavor QCD. In the study the Iwasaki gauge action and non-perturvatively\nO($a$) improved Wilson-Clover fermion action are employed. We discuss finite\nsize scaling analysis including mixings of magnetization-like and energy-like\nobservables. Preliminary results are shown of the continuum limit of the\ncritical point using newly generated data at Nt=8,10, including estimates of\nthe critical pseudo-scalar meson mass and critical temperature."
    },
    {
        "anchor": "Estimating the two-particle $K$-matrix for multiple partial waves and\n  decay channels from finite-volume energies: An implementation of estimating the two-to-two $K$-matrix from finite-volume\nenergies based on the L\\\"uscher formalism and involving a Hermitian matrix\nknown as the \"box matrix\" is described. The method includes higher partial\nwaves and multiple decay channels. Two fitting procedures for estimating the\n$K$-matrix parameters, which properly incorporate all statistical covariances,\nare discussed. Formulas and software for handling total spins up to $S=2$ and\norbital angular momenta up to $L=6$ are obtained for total momenta in several\ndirections. First tests involving $\\rho$-meson decay to two pions include the\n$L=3$ and $L=5$ partial waves, and the contributions from these higher waves\nare found to be negligible in the elastic energy range.",
        "positive": "K\u00e4hler-Dirac fermions on Euclidean dynamical triangulations: We study K\\\"ahler-Dirac fermions on Euclidean dynamical triangulations. This\nfermion formulation furnishes a natural extension of staggered fermions to\nrandom geometries without requring vielbeins and spin connections. We work in\nthe quenched approximation where the geometry is allowed to fluctuate but there\nis no back-reaction from the matter on the geometry. By examining the\neigenvalue spectrum and the masses of scalar mesons we find evidence for a four\nfold degeneracy in the fermion spectrum in the large volume, continuum limit.\nIt is natural to associate this degeneracy with the well known equivalence in\ncontinuum flat space between the K\\\"ahler-Dirac fermion and four copies of a\nDirac fermion. Lattice effects then lift this degeneracy in a manner similar to\nstaggered fermions on regular lattices. The evidence that these discretization\neffects vanish in the continuum limit suggests both that lattice continuum\nK\\\"ahler-Dirac fermions are recovered at that point, and that this limit truly\ncorresponds to smooth continuum geometries. One additional advantage of the\nK\\\"ahler-Dirac action is that it respects an exact $U(1)$ symmetry on any\nrandom triangulation. This $U(1)$ symmetry is related to continuum chiral\nsymmetry. By examining fermion bilinear condensates we find strong evidence\nthat this $U(1)$ symmetry is not spontaneously broken in the model at order the\nPlanck scale. This is a necessary requirement if models based on dynamical\ntriangulations are to provide a valid ultraviolet complete formulation of\nquantum gravity."
    },
    {
        "anchor": "Higgsing Gauge Symmetries with Reduced Staggered Fermions: We show how a strongly coupled lattice theory consisting of just fermions and\ngauge fields can exhibit a dynamical Higgs mechanism through the formation of a\ngauge invariant four fermion condensate. Furthermore, we argue that the\nresultant lattice Higgs phase may survive into the continuum limit.",
        "positive": "A study of large field configurations in MC simulations: We discuss a new approach of scalar field theory where the small field\ncontributions are treated perturbatively and the large field configurations\n(which are responsible for the asymptotic behavior of the perturbative series)\nare neglected. In two Borel summable lambda phi ^4 problems improved\nperturbative series can be obtained by this procedure. The modified series\nconverge towards values exponentially close to the exact ones. For lambda\nlarger than some critical value, the method outperforms Pade approximants and\nBorel summations. The method can also be used for series which are not Borel\nsummable such as the double-well potential series and provide a perturbative\napproach of the instanton contribution. Semi-classical methods can be used to\ncalculate the modified Feynman rules, estimate the error and optimize the field\ncutoff. We discuss Monte Carlo simulations in one and two dimensions which\nsupport the hypothesis of dilution of large field configurations used in these\nsemi-classical calculations. We show that Monte Carlo methods can be used to\ncalculate the modified perturbative series."
    },
    {
        "anchor": "Hamiltonian models of lattice fermions solvable by the meron-cluster\n  algorithm: We introduce a half-filled Hamiltonian of spin-half lattice fermions that can\nbe studied with the efficient meron-cluster algorithm in any dimension. As with\nthe usual bipartite half-filled Hubbard models, the na\\\"ive $U(2)$ symmetry is\nenhanced to $SO(4)$. On the other hand our model has a novel spin-charge flip\n${\\mathbb Z}^C_2$ symmetry which is an important ingredient of free massless\nfermions. In this work we focus on one spatial dimension, and show that our\nmodel can be viewed as a lattice-regularized two-flavor chiral-mass Gross-Neveu\nmodel. Our model remains solvable in the presence of the Hubbard coupling $U$,\nwhich maps to a combination of Gross-Neveu and Thirring couplings in one\ndimension. Using the meron-cluster algorithm we find that the ground state of\nour model is a valence bond solid when $U=0$. From our field theory analysis,\nwe argue that the valence bond solid forms inevitably because of an interesting\nfrustration between spin and charge sectors in the renormalization group flow\nenforced by the ${\\mathbb Z}^C_2$ symmetry. This state spontaneously breaks\ntranslation symmetry by one lattice unit, which can be identified with a\n$\\mathbb{Z}_2^\\chi$ chiral symmetry in the continuum. We show that increasing\n$U$ induces a quantum phase transition to a critical phase described by the\n$SU(2)_1$ Wess-Zumino-Witten theory. The quantum critical point between these\ntwo phases is known to exhibit a novel symmetry enhancement between spin and\ndimer. Here we verify the scaling relations of these correlation functions near\nthe critical point numerically. Our study opens up the exciting possibility of\nnumerical access to similar novel phase transitions in higher dimensions in\nfermionic lattice models using the meron-cluster algorithm.",
        "positive": "Auxiliary field Monte-Carlo simulation of strong coupling lattice QCD\n  for QCD phase diagram: We study the QCD phase diagram in the strong coupling limit with fluctuation\neffects by using the auxiliary field Monte-Carlo method. We apply the chiral\nangle fixing technique in order to obtain finite chiral condensate in the\nchiral limit in finite volume. The behavior of order parameters suggests that\nchiral phase transition is the second order or crossover at low chemical\npotential and the first order at high chemical potential. Compared with the\nmean field results, the hadronic phase is suppressed at low chemical potential,\nand is extended at high chemical potential as already suggested in the\nmonomer-dimer-polymer simulations. We find that the sign problem originating\nfrom the bosonization procedure is weakened by the phase cancellation\nmechanism; a complex phase from one site tends to be canceled by the nearest\nneighbor site phase as long as low momentum auxiliary field contributions\ndominate."
    },
    {
        "anchor": "Improved Hamiltonian for Minkowski Yang-Mills Theory: I develop an improved Hamiltonian for classical, Minkowski Yang-Mills theory,\nwhich evolves infrared fields with corrections from lattice spacing $a$\nbeginning at $O(a^4)$. I use it to investigate the response of Chern-Simons\nnumber to a chemical potential, and to compute the maximal Lyapunov exponent.\nBoth quantities have small $a$ limits, in both cases within $10\\% $ of the\nlimit found using the unimproved (Kogut Susskind) Hamiltonian. For the maximal\nLyapunov exponent the limits differ by about $5 \\% $, significant at about $5\n\\sigma$, indicating that while a small $a$ limit exists, its value is corrupted\nby lattice artefacts. For the response of Chern-Simons number the statistics\nare not good enough to resolve $ 5 \\% $ differences, but it seems possible in\nanalogy with the Lyapunov exponent that the final answer depends on the lattice\nregulation.",
        "positive": "Supersymmetric Yang--Mills theories with exact supersymmetry on the\n  lattice: Inspired by the ideas from topological field theory it is possible to rewrite\nthe supersymmetric charges of certain classes of extended supersymmetric\nYang--Mills (SYM) theories in such a way that they are compatible with the\ndiscretization on a Euclidean spacetime lattice. Such theories are known as\nmaximally twisted SYM theories. In this review we discuss the construction and\nsome applications of such classes of theories. The one-loop perturbative\nrenormalization of the four-dimensional lattice ${\\cal N}=4$ SYM is discussed\nin particular. The lattice theories constructed using twisted approach play an\nimportant role in investigating the thermal phases of strongly coupled SYM\ntheories and also the thermodynamic properties of their dual gravitational\ntheories."
    },
    {
        "anchor": "Lattice Fermionic Casimir effect in a Slab Bag and Universality: We apply the physically more appealing MIT Bag boundary conditions to study\nthe Casimir effect on the lattice. Employing the formalism of arXiv:2005.10758\nto calculate the Casimir energy for free lattice fermions, we show that the\nresults for the naive, Wilson and overlap fermions match the continuum\nexpressions precisely in the zero lattice spacing limit, as expected from\nuniversality. In contrast to arXiv:2005.10758 where the result for the naive\nfermions rapidly oscillates with the lattice size for both, the periodic (P)\nand anti-periodic (AP) boundary conditions, no oscillations are observed with\nthe lattice size. Furthermore, the apparent violation of the universality for\nnaive fermion in arXiv:2005.10758 is shown to be cured by applying suitable\nseries extrapolation techniques, thus demonstrating that the Casimir energy for\nthe naive fermions with periodic/antiperiodic boundary conditions agrees with\nthe results for other free lattice fermions, and can as well be used to obtain\nthe results for the Dirac fermion in the zero limit of the lattice spacing.",
        "positive": "Grassmann tensor renormalization group for one-flavor lattice\n  Gross-Neveu model with finite chemical potential: We apply the Grassmann tensor renormalization group (GTRG) to the one-flavor\nlattice Gross-Neveu model in the presence of chemical potential. We compute the\nfermion number density and its susceptibility and confirm the validity of GTRG\nfor the finite density system. We introduce a method analogous to the\nreweighting method for Monte Carlo method and test it for some parameters."
    },
    {
        "anchor": "Flux tube widening in compact U (1) lattice gauge theory computed at T <\n  Tc with the multilevel method and GPUs: We utilize Polyakov loop correlations to study d=3+1 compact U (1) flux tubes\nand the static electron-positron potential in lattice gauge theory. With the\nplaquette field operator, in U(1) lattice gauge theory, we probe directly the\ncomponents of the electric and magnetic fields. In order to improve the\nsignal-to-noise ratio in the confinement phase, we apply the L\\\"uscher-Weiss\nmultilevel algorithm. Our code is written in CUDA, and we run it in NVIDIA\nFERMI generation GPUs, in order to achieve the necessary efficiency for our\ncomputations. We measure in detail the quantum widening of the flux tube, as a\nfunction of the intercharge distance and at different finite temperatures T <\nTc . Our results are compatible with the Effective String Theory.",
        "positive": "Center vortex properties in the Laplace center gauge of SU(2) Yang-Mills\n  theory: Resorting to the the Laplace center gauge (LCG) and to the Maximal-center\ngauge (MCG), respectively, confining vortices are defined by center projection\nin either case. Vortex properties are investigated in the continuum limit of\nSU(2) lattice gauge theory. The vortex (area) density and the density of vortex\ncrossing points are investigated. In the case of MCG, both densities are\nphysical quantities in the continuum limit. By contrast, in the LCG the\npiercing as well as the crossing points lie dense in the continuum limit. In\nboth cases, an approximate treatment by means of a weakly interacting vortex\ngas is not appropriate."
    },
    {
        "anchor": "Coordinate space methods for the evaluation of Feynman diagrams in\n  lattice field theory: We describe an efficient position space technique to calculate lattice\nFeynman integrals in infinite volume. The method applies to diagrams with\nmassless propagators. For illustration a set of two-loop integrals is worked\nout explicitly. An important ingredient is an observation of Vohwinkel that the\nfree lattice propagator can be evaluated recursively and is expressible as a\nlinear function of its values near the origin.",
        "positive": "Analytic Variational Investigation of Euclidean SU(3) Gauge Theory: Analytic variational techniques for lattice gauge theories based on the\nRayleigh-Ritz(RR) method were previously developed for euclidean SU(2) gauge\ntheories in 3 and 4 dimensions. Their extensions to SU(3) gauge theory\nincluding applications to correlation functions and mass gaps are presented\nhere."
    },
    {
        "anchor": "Towards a determination of the spectrum of QCD using a space-time\n  lattice: Progress by the Lattice Hadron Physics Collaboration in determining the\nbaryon and meson resonance spectrum of QCD using Monte Carlo methods with\nspace-time lattices is described. The extraction of excited-state energies\nnecessitates the evaluation of correlation matrices of sets of operators, and\nthe importance of extended three-quark operators to capture both the radial and\norbital structures of baryons is emphasized. The use of both quark-field\nsmearing and link-field smearing in the operators is essential for reducing the\ncouplings of the operators to the high-frequency modes and for reducing\nstatistical noise in the correlators. The extraction of nine energy levels in a\ngiven symmetry channel is demonstrated, and identifying the continuum spin\nquantum numbers of the levels is discussed.",
        "positive": "Multigrid Monte Carlo in the Sine Gordon model: We pose two questions about the dynamical critical behavior of multigrid\nMonte Carlo: Will a multigrid Monte Carlo simulation of the two dimensional\nSine Gordon model exhibit critical slowing down, as expected by a theoretical\nanalysis of Metropolis acceptance rates? Can we reduce critical slowing down\ncaused by decreasing acceptance rates on large blocks by performing more\nupdates on coarser lattices? To this end we simulate the model with a W-cycle\n(gamma = 2) and a higher cycle with gamma = 4 using piecewise constant\ninterpolation. The answer to the first question is positive, the answer to the\nsecond one is negative."
    },
    {
        "anchor": "Renormalons: The calculation of higher twist (or dimension) corrections to physical\nquantities using operator product expansions is delicate. If dimensional\nregularization is used to regulate the ultra-violet divergences then there are\nambiguities in the Wilson coefficient functions due to infra-red renormalon\nsingularities. With a hard ultra violet cut-off, such as the inverse lattice\nspacing $a$, there are no renormalon ambiguities, as a result of cancellations\nbetween terms which in finite orders of perturbation theory diverge as inverse\npowers of $a$, and those which diverge at most logarithmically. In this lecture\nI review these questions, explaining the steps necessary to obtain predictions\nfor physical quantities from lattice measurements of matrix elements of higher\ndimensional operators. The ideas are illustrated by considering quantities\ncomputed using the heavy quark effective theory beyond leading order in the\nheavy quark mass.",
        "positive": "Kaon-Nucleon potential from lattice QCD: We study the KN interactions in the I(J^{\\pi})=0(1/2^-) and 1(1/2^-) channels\nand associated exotic state \\Theta^+ from 2+1 flavor full lattice QCD\nsimulation for relatively heavy quark mass corresponding to m_{\\pi}=871 MeV.\nThe s-wave KN potentials are obtained from the Bethe-Salpeter wave function by\nusing the method recently developed by HAL QCD (Hadrons to Atomic nuclei from\nLattice QCD) Collaboration. Potentials in both channels reveal short range\nrepulsions: Strength of the repulsion is stronger in the I=1 potential, which\nis consistent with the prediction of the Tomozawa-Weinberg term. The I=0\npotential is found to have attractive well at mid range. From these potentials,\nthe $KN$ scattering phase shifts are calculated and compared with the\nexperimental data."
    },
    {
        "anchor": "Matrix Distributed Processing: A set of C++ Tools for implementing\n  generic lattice computations on parallel systems: We present a set of programming tools (classes and functions written in C++\nand based on Message Passing Interface) for fast development of generic\nparallel (and non-parallel) lattice simulations. They are collectively called\nMDP 1.2.\n  These programming tools include classes and algorithms for matrices, random\nnumber generators, distributed lattices (with arbitrary topology), fields and\nparallel iterations. No previous knowledge of MPI is required in order to use\nthem.\n  Some applications in electromagnetism, electronics, condensed matter and\nlattice QCD are presented.",
        "positive": "The Quantized $O(1,2)/O(2)\\times Z_2$ Sigma Model Has No Continuum Limit\n  in Four Dimensions. II. Lattice Simulation: A lattice formulation of the $O(1,2)/O(2)\\times Z_2$ sigma model is\ndeveloped, based on the continuum theory presented in the preceding paper.\nSpecial attention is given to choosing a lattice action (the ``geodesic''\naction) that is appropriate for fields having noncompact curved configuration\nspaces. A consistent continuum limit of the model exists only if the\nrenormalized scale constant $\\beta_R$ vanishes for some value of the bare scale\nconstant~$\\beta$. The geodesic action has a special form that allows direct\naccess to the small-$\\beta$ limit. In this limit half of the degrees of freedom\ncan be integrated out exactly. The remaining degrees of freedom are those of a\ncompact model having a $\\beta$-independent action which is noteworthy in being\nunbounded from below yet yielding integrable averages. Both the exact action\nand the $\\beta$-independent action are used to obtain $\\beta_R$ from Monte\nCarlo computations of field-field averages (2-point functions) and\ncurrent-current averages. Many consistency cross-checks are performed. It is\nfound that there is no value of $\\beta$ for which $\\beta_R$ vanishes. This\nmeans that as the lattice cutoff is removed the theory becomes that of a pair\nof massless free fields. Because these fields have neither the geometry nor the\nsymmetries of the original model we conclude that the $O(1,2)/O(2)\\times Z_2$\nmodel has no continuum limit."
    },
    {
        "anchor": "Simulating full QCD at nonzero density using the complex Langevin\n  equation: The complex Langevin method is extended to full QCD at non-zero chemical\npotential. The use of gauge cooling stabilizes the simulations at small enough\nlattice spacings. At large fermion mass the results are compared to the HQCD\napproach, in which the spatial hoppings of fermionic variables are neglected,\nand good agreement is found. The method allows simulations also at high\ndensities, all the way up to saturation.",
        "positive": "Mass Splitting of Staggered Fermion and $SO(2D)$ Clifford Algebra: We present a new method to introduce rotationally invariant terms in\nstaggered fermions which is based on an $SO(2D)$ Clifford algebra formulation,\nwhere $D$ means the number of space-time dimensions. We have four candidates\nfor improved mass terms that can split the degenerate mass of staggered\nfermions. Among them, we analyze three types of combinations and find only one\ncase that can identify with the light single Dirac mode."
    },
    {
        "anchor": "NLO and NNLO Low Energy Constants for $SU(2)$ Chiral Perturbation Theory: We have performed global fits of $f_{\\pi}$ and $m_{\\pi}$, from a variety of\nRBC-UKQCD domain wall fermion ensembles, to $SU(2)$ partially quenched chiral\nperturbation theory at NNLO. We report values for 9 NLO and 8 linearly\nindependent combinations of NNLO partially quenched low energy constants, which\nwe compare to other lattice and phenomenological determinations. We discuss the\nconvergence of the expansion and use our large set of low energy constants to\nmake predictions for the pion mass splitting due to QCD isospin breaking\neffects and the s-wave $\\pi \\pi$ scattering lengths. We conclude that, for the\nrange of pseudoscalar masses explored in this work, $115~\\mathrm{MeV} \\lesssim\nm_{\\rm PS} \\lesssim 430~\\mathrm{MeV}$, the NNLO $SU(2)$ expansion is quite\nrobust and can fit lattice data with percent-scale accuracy.",
        "positive": "Lattice Generalized Parton Distributions and Form Factors of the Nucleon: In these proceedings we discuss recent progress in nucleon structure using\nlattice QCD simulations at or near the physical value of the pion mass. Main\nfocus will be given in observables such as the nucleon axial charge and the\nfirst moments of parton distributions, for both the valence and sea quark\ncontributions, and discuss their implications on the spin content of the\nnucleon. We will will also report developments on the evaluation of the gluon\nmomentum fraction, which contributes significantly to the nucleon spin."
    },
    {
        "anchor": "Mobility edge in lattice QCD: We determine the location $\\lambda_c$ of the mobility edge in the spectrum of\nthe hermitian Wilson operator on quenched ensembles. We confirm a theoretical\npicture of localization proposed for the Aoki phase diagram. When $\\lambda_c>0$\nwe also determine some key properties of the localized eigenmodes with\neigenvalues $|\\lambda|<\\lambda_c$. Our results lead to simple tests for the\nvalidity of simulations with overlap and domain-wall fermions.",
        "positive": "Calculation of kaon semileptonic form factor with the PACS10\n  configuration: We present preliminary results for the kaon semileptonic form factors using\nthe PACS10 configurations, whose physical volume is more than (10 fm)$^3$ at\nthe physical point with the lattice spacings of 0.085 and 0.064 fm. The\nconfigurations were generated using the Iwasaki gauge action and $N_f=2+1$\nstout-smeared Clover quark action. For the continuum extrapolation, we\ncalculate the form factors with the local and conserved vector currents. The\nform factors in the two lattice spacings are extrapolated to the continuum\nlimit using a fit function based on the NLO SU(3) ChPT formula with terms\ncorresponding to finite lattice spacing effects. The value of $|V_{us}|$ is\ndetermined using our preliminary result of the form factor at the zero momentum\ntransfer in the continuum limit. The result is compared with recent lattice\nresults, and also predictions of the standard model from the unitarity of the\nCabibbo-Kobayashi-Maskawa (CKM) matrix."
    },
    {
        "anchor": "$DK$ $I=0,$ $D\\bar{K}$ $I=0,1$ scattering and the $D_{s0}^\\ast(2317)$\n  from lattice QCD: Elastic scattering amplitudes for $I=0$ $DK$ and $I=0,1$ $D\\bar{K}$ are\ncomputed in $S$, $P$ and $D$ partial waves using lattice QCD with light-quark\nmasses corresponding to $m_\\pi = 239$ MeV and $m_\\pi = 391$ MeV. The $S$-waves\ncontain interesting features including a near-threshold $J^P=0^+$ bound state\nin $I=0$ $DK$, corresponding to the $D_{s0}^\\ast(2317)$, with an effect that is\nclearly visible above threshold, and suggestions of a $0^+$ virtual bound state\nin $I=0$ $D\\bar{K}$. The $S$-wave $I=1$ $D\\bar{K}$ amplitude is found to be\nweakly repulsive. The computed finite-volume spectra also contain a\ndeeply-bound $D^\\ast$ vector resonance, but negligibly small $P$-wave $DK$\ninteractions are observed in the energy region considered; the $P$ and $D$-wave\n$D\\bar{K}$ amplitudes are also small. There is some evidence of $1^+$ and $2^+$\nresonances in $I=0$ $DK$ at higher energies.",
        "positive": "Exploring gauge theories with adjoint matter on the lattice: We review our efforts in investigating gauge theories with fermions in the\nadjoint representation of the gauge group by means of numerical simulations.\nThese theories have applications in possible extensions of the Standard Model\nof particle physics, being a core part of supersymmetric gauge theories. They\nalso play an important role in uncovering fundamental properties of strongly\ninteracting theories due to distinct features, such as a substantially\ndifferent phase diagram."
    },
    {
        "anchor": "Comparing Pure Yang-Mills SU(2) and SU(3) Propagators: The infrared behavior of gluon and ghost propagators in Yang-Mills gauge\ntheories is of central importance for the understanding of confinement in QCD.\nWhile analytic studies using Schwinger-Dyson equations predict the same\ninfrared exponents for the SU(2) and SU(3) gauge groups, lattice simulations\nusually assume that the two cases are different, although their qualitative\ninfrared features may be the same. We carry out a comparative study of lattice\n(Landau) propagators for both gauge groups. Our data were especially produced\nwith equivalent lattice parameters to allow a careful comparison of the two\ncases.",
        "positive": "Deconstruction and other approaches to supersymmetric lattice field\n  theories: This report contains both a review of recent approaches to supersymmetric\nlattice field theories and some new results on the deconstruction approach. The\nessential reason for the complex phase problem of the fermion determinant is\nshown to be derivative interactions that are not present in the continuum.\nThese irrelevant operators violate the self-conjugacy of the fermion action\nthat is present in the continuum. It is explained why this complex phase\nproblem does not disappear in the continuum limit. The fermion determinant\nsuppression of various branches of the classical moduli space is explored, and\nfound to be supportive of previous claims regarding the continuum limit."
    },
    {
        "anchor": "Mesons in large-N QCD: We present the results of a systematic, first-principles study of the\nspectrum and decay constants of mesons for different numbers of color charges\nN, via lattice computations. We restrict our attention to states in the\nnon-zero isospin sector, evaluating the masses associated with the ground-state\nand first excitation in the pseudoscalar, vector, scalar, and axial vector\nchannels. Our results are based on a new set of simulations of four dimensional\nSU(N) Yang-Mills theories with the number of colors ranging from N=2 to N=17;\nthe spectra and the decay constants are computed in the quenched approximation\n(which becomes exact in the 't Hooft limit) using Wilson fermions. After\ndiscussing the extrapolations to the chiral and large-N limits, we present a\ncomparison of our results to some of the numerical computations and analytical\npredictions available in the literature - including, in particular, those from\nholographic computations.",
        "positive": "B -> D* l nu with 2+1 flavors: We present a calculation of the form factor for B -> D* l nu using a 2+1\nimproved staggered action for the light quarks (on the MILC configurations),\nand the Fermilab action for the heavy quarks. The form factor is computed at\nzero recoil using a new double ratio method which yields the form factor more\ndirectly than previous approaches."
    },
    {
        "anchor": "Towards flavour diffusion coefficient and electrical conductivity\n  without ultraviolet contamination: By subtracting from a recent lattice measurement of the thermal\nvector-current correlator the known 5-loop vacuum contribution, we demonstrate\nthat the remainder is small and shows no visible short-distance divergence. It\ncan therefore in principle be subjected to model-independent analytic\ncontinuation. Testing a particular implementation, we obtain estimates for the\nflavour-diffusion coefficient (2 pi T D \\gsim 0.8) and electrical conductivity\nwhich are significantly smaller than previous results. Although systematic\nerrors remain beyond control at present, some aspects of our approach could be\nof a wider applicability.",
        "positive": "Dynamical Properties of Large N Reduced Model of Yang-Mills Theory: We study the large N reduced model of D-dimensional Yang-Mills theory with\nspecial attention to the dynamical aspects related to the eigenvalues of the\nNxN matrices, which correspond to the space-time coordinates in the IIB matrix\nmodel. We define a quantity which represents the uncertainty of the space-time\ncoordinates and show that it is of the same order as the extent of the space\ntime, which means that the classical space-time picture is maximally broken.\nThe absence of the SSB of the Lorentz invariance is also shown."
    },
    {
        "anchor": "Improving DWF Simulations: the Force Gradient Integrator and the\n  M\u00f6bius Accelerated DWF Solver: We have implemented a variant of the force gradient integrator proposed by\nKennedy et.al. and are using it in our production 2+1 flavor DWF simulations\nwith pion masses of 180 MeV in (4.5fm)3 volumes. We find modest speed-ups (\\sim\n20%) from using the force gradient integrator, compared to our previously used\nOmelyan integrator. On other ensembles, primarily finite temperature 2+1 flavor\nDWF QCD, we have extensively tuned the Hasenbusch preconditioning masses and\nachieved speed-ups of 2-3x. Here we have also switched to the force gradient\nintegrator, but this change has not had any impact on the speed. We also report\non an improved solver for DWF, which uses M\\\"obius fermions, with a smaller\nfifth dimension than the original DWF fermions, as an intermediate step in the\ngeneration of solutions of the Dirac equation. This approach cuts the number of\neffective Dirac applications by approximately a factor of 2 when the conjugate\ngradient iteration count is large.",
        "positive": "Dynamical suppression of large instantons: We investigate the distribution of instanton sizes in the framework of a\nsimplified model for ensembles of instantons. This model takes into account the\nnon-diluteness of instantons. The infrared problem for the integration over\ninstanton sizes is dealt with in a self-consistent manner by approximating\ninstanton interactions by a repulsive hard core potential. This leads to a\ndynamical suppression of large instantons. The characteristic features of the\ninstanton size distribution are studied by means of analytic and Monte Carlo\nmethods. We find a power law behaviour for small sizes, consistent with the\nsemi-classical results. At large instanton sizes the distribution decays\nexponentially. The results are compared with those from lattice simulations."
    },
    {
        "anchor": "Confinement Mechanism in Various Abelian Projections of Lattice\n  Gluodynamics: We show that the monopole confinement mechanism in lattice gluodynamics may\nbe a particular feature of the maximal abelian projection. We give an explicit\nexample of the $SU(2) \\rightarrow U(1)$ projection (the minimal abelian\nprojection), in which the confinement is due to topological objects other than\nmonopoles. We also discuss the string representation of the abelian projected\n$SU(2)$ gluodynamics.",
        "positive": "The gradient flow running coupling in SU(2) gauge theory with $N_f=8$\n  fundamental flavors: We study the evolution of the coupling in SU(2) gauge field theory with\n$N_f=8$ fundamental fermion flavors on the lattice. This model is expected to\nhave an infrared fixed point at high coupling. We use HEX-smeared Wilson-clover\naction, and measure the gradient flow running coupling with Dirichlet boundary\nconditions. Extrapolating our results to continuum, we find an infrared fixed\npoint at $g^2=8.24(59)^{+0.97}_{-1.64}$, with statistical and systematic error\nestimates. We also measure the anomalous dimension of the quark mass operator,\nand find its value at the fixed point $\\gamma \\approx 0.15 \\pm 0.02$."
    },
    {
        "anchor": "Lattice gauge theories in the strong coupling and static limits as a\n  sign-problem-free Ising model: The effective action of the SU(N) Polyakov loop model in the strong coupling\nregion and in the static limit for the quark determinant can be mapped onto the\nIsing model in any dimensions, with the Ising variables attached on the links\nof the lattice. We use this reformulation to study the finite temperature SU(2)\nlattice gauge theory at finite baryon density.",
        "positive": "Lattice 2001: Reflections: A few subjects which strongly intertwine our field are discussed: K --> Pi Pi\ndecay, chiral symmetry on the lattice and a few other selected topics. Open\nquestions are touched also on perturbation theory, locality, Gribov copies, CP\nsymmetry in chiral gauge theories and cut-off effects."
    },
    {
        "anchor": "Exact Correlators in the 't Hooft Limit of the Principal Chiral Model: The properties of (N X N)-matrix-valued-field theories, in the limit N goes\nto infinity, are harder to obtain than those for isovector-valued field\ntheories. This is because we know less about the sum of planar diagrams than\nthe sum of bubble/linear diagrams. Combining the 1/N-expansion with the axioms\nfor form factors, exact form factors can be found for the integrable field\ntheory of an SU(N)-valued field in 1+1 dimensions. These form factors can be\nused to find the vacuum expectation value of the product of two field\noperators. We briefly mention how the results can be applied to 2+1 dimensional\ngauge theories.",
        "positive": "The relation between the waveguide and overlap implementations of\n  Kaplan's domain wall fermions: Recently, Narayanan and Neuberger proposed that the fermion determinant for a\nlattice chiral gauge theory be defined by an overlap formula. The motivation\nfor that formula comes from Kaplan's five dimensional lattice domain wall\nfermions. In the case that the target continuum theory contains $4n$ chiral\nfamilies, we show that the effective action defined by overlap formula is\nidentical to the effective action of a modified waveguide model that has extra\nbosonic ghost fields. This raises serious questions about the viability of the\noverlap formula for defining chiral gauge theories on the lattice."
    },
    {
        "anchor": "Color screening in $2+1$ flavor QCD at large distances: We study correlation functions of spatially separated static quark-antiquark\npairs in $2+1$ flavor QCD in order to investigate the nature of color screening\nat high temperatures. We perform lattice calculations in a wide temperature\nrange, $116~\\text{MeV} \\leq T \\leq 5814~\\text{MeV}$, using the highly improved\nstaggered quark (HISQ) action and several lattice spacings to control\ndiscretization effects. We alleviate the UV noise problem through the use of\nfour dimensional hypercubic (HYP) smearing, which enables the reconstruction of\ncorrelators and determination of screening properties even at low temperatures\nand at large distances.",
        "positive": "The strange quark mass and Lambda parameter of two flavor QCD: We complete the non-perturbative calculations of the strange quark mass and\nthe Lambda parameter in two flavor QCD by the ALPHA collaboration. The missing\nlattice scale is determined via the kaon decay constant, for whose chiral\nextrapolation complementary strategies are compared. We also give a value for\nthe scale r_0 in physical units as well as an improved determination of the\nrenormalization constant Z_A."
    },
    {
        "anchor": "Dual Superconductor Mechanism of Confinement on the Lattice: We investigate the dual superconductor mechanism of confinement for pure\nSU(2) lattice gauge theory in the maximally abelian gauge. We focus on the the\ndual Meissner effect. We find that the transverse distribution of the\nlongitudinal chromoelectric field due to a static quark-antiquark pair\nsatisfies the dual London equation. Moreover we show that the size of the flux\ntube scales according to asymptotic freedom.",
        "positive": "Volume dependence of Fisher's zeros: We study the location of the partition function zeros in the complex beta\nplane (Fisher's Zeros) for SU(2) lattice gauge theory on L^4 lattices. We\ndiscuss recent attempts to locate complex zeros for L=4 and 6. We compare\nresults obtained using various polynomial approximations of the logarithm of\nthe density of states and a straightforward MC reweighting. We conclude that\nthe method based on a combination of discrete Chebyshev orthogonality and\npatching plaquette distributions at different beta provides the more reliable\nestimates."
    },
    {
        "anchor": "Predictions for LHC from SO(4) MWT: We investigate the vector, axial and pseudo scalar mass spectrum of an SO(4)\n- MWT gauge theory with fermions in the vector representation of SO(4). Here we\npresent the preliminary lattice results for the masses of vector and axial\nvector meson using Wilson fermions. These spectra are crucial for the discovery\nand to guide the searches of composite dynamics at the LHC.",
        "positive": "Comment on \"Are two nucleons bound in lattice QCD for heavy quark\n  masses? - Sanity check with L\u00fcscher's finite volume formula -\": In this comment, we address a number of erroneous discussions and conclusions\npresented in a recent preprint by the HALQCD collaboration, arXiv:1703.07210.\nIn particular, we demonstrate that lattice QCD determinations of bound states\nat quark masses corresponding to a pion mass of $m_\\pi = 806$ MeV are robust,\nand that the phases shifts extracted by the NPLQCD collaboration for these\nsystems pass all of the 'sanity checks' introduced in arXiv:1703.07210."
    },
    {
        "anchor": "Magnetic Moment of Vector Mesons in the Background Field Method: We report some results for the magnetic moments of vector mesons extracted\nfrom mass shifts in the presence of static external magnetic fields. The\ncalculations are done on $24^4$ quenched lattices using standard Wilson\nactions, with $\\beta$=6.0 and pion mass down to 500 MeV. The results are\ncompared to those from the form factor method.",
        "positive": "Monte Carlo studies of three-dimensional O(1) and O(4)\n  \\boldmath{$\u03c6^4$} theory related to BEC phase transition temperatures: The phase transition temperature for the Bose-Einstein condensation (BEC) of\nweakly-interacting Bose gases in three dimensions is known to be related to\ncertain non-universal properties of the phase transition of three-dimensional\nO(2) symmetric $\\phi^4$ theory. These properties have been measured previously\nin Monte Carlo lattice simulations. They have also been approximated\nanalytically, with moderate success, by large $N$ approximations to O($N$)\nsymmetric $\\phi^4$ theory. To begin investigating the region of validity of the\nlarge $N$ approximation in this application, I have applied the same Monte\nCarlo technique developed for the O(2) model ([5]) to O(1) and O(4) theories.\nMy results indicate that there might exist some theoretically unanticipated\nsystematic errors in the extrapolation of the continuum value from lattice\nMonte Carlo results. The final results show that the difference between\nsimulations and NLO large $N$ calculations does not improve significantly from\nN=2 to N=4. This suggests one would need to simulate yet larger $N$'s to see\ntrue large $N$ scaling of the difference. Quite unexpectedly (and presumably\naccidentally), my Monte Carlo result for N=1 seems to give the best agreement\nwith the large $N$ approximation among the three cases."
    },
    {
        "anchor": "SU(2N_F) symmetry of QCD at high temperature and its implications: If above a critical temperature not only the SU(N_F)_L \\times SU(N_F)_R\nchiral symmetry of QCD but also the U(1)_A symmetry is restored, then the\nactual symmetry of the QCD correlation functions and observables is SU(2N_F).\nSuch a symmetry prohibits existence of deconfined quarks and gluons. Hence QCD\nat high temperature is also in the confining regime and elementary objects are\nSU(2N_F) symmetric \"hadrons\" with not yet known properties.",
        "positive": "The Structure of Flux-tubes in SU(2): The spatial distribution of the action and energy in the colour fields of\nflux-tubes is studied in lattice SU(2) field theory for static quarks at\nseparations up to 1 fm. Special attention is paid to the structure of the\ncolour fields associated with an excited flux-tube with E_u symmetry. We\ncompare our results with hadronic string and flux-tube models. Sum rules are\nused to extract generalised beta-functions, to describe the expected colour\nfield behaviour and to cross check the methods used."
    },
    {
        "anchor": "Open-Boundary Conditions in the Deconfined Phase: In this work, we consider open-boundary conditions at high temperatures, as\nthey can potentially be of help to measure the topological susceptibility. In\nparticular, we measure the extent of the boundary effects at $T=1.5T_c$ and\n$T=2.7T_c$. In the first case, it is larger than at $T=0$ while we find it to\nbe smaller in the second case. The length of this \"boundary zone\" is controlled\nby the screening masses. We use this fact to measure the scalar and\npseudo-scalar screening masses at these two temperatures. We observe a mass gap\nat $T=1.5T_c$ but not at $T=2.7T_c$. Finally, we use our pseudo-scalar channel\nanalysis to estimate the topological susceptibility. The results at $T=1.5T_c$\nare in good agreement with the literature. At $T=2.7T_c$, they appear to suffer\nfrom topological freezing, impeding us from providing a precise determination\nof the topological susceptibility. It still provides us with a lower bound,\nwhich is already in mild tension with some of the existing results.",
        "positive": "Spectral properties and lattice-size dependences in cluster algorithms: Simulation results of Ising systems for several update rules, observables,\nand dimensions are analyzed. The lattice-size dependence is discussed for the\nautocorrelation times and for the weights of eigenvalues, giving fit results in\nthe case of power laws. Implications of spectral properties are pointed out and\nthe behavior of a particular observable not governed by detailed balance is\nexplained."
    },
    {
        "anchor": "Lattice QCD study of a five-quark hadronic molecule: We compute the ground-state energies of a heavy-light K-Lambda like system as\na function of the relative distance r of the hadrons. The heavy quarks, one in\neach hadron, are treated as static. Then, the energies give rise to an\nadiabatic potential Va(r) which we use to study the structure of the five-quark\nsystem. The simulation is based on an anisotropic and asymmetric lattice with\nWilson fermions. Energies are extracted from spectral density functions\nobtained with the maximum entropy method. Our results are meant to give\nqualitative insight: Using the resulting adiabatic potential in a Schroedinger\nequation produces bound state wave functions which indicate that the ground\nstate of the five-quark system resembles a hadronic molecule, whereas the first\nexcited state, having a very small rms radius, is probably better described as\na five-quark cluster, or a pentaquark. We hypothesize that an all light-quark\npentaquark may not exist, but in the heavy-quark sector it might, albeit only\nas an excited state.",
        "positive": "Quark propagator in Landau and Laplacian gauges with overlap fermions: The properties of the momentum space quark propagator in Landau gauge and\nGribov copy free Laplacian gauge are studied for the overlap quark action in\nquenched lattice QCD. Numerical calculations are done on two lattices with\ndifferent lattice spacing $a$ and the same physical volume. We have calculated\nthe nonperturbative wave function renormalization function $Z(q)$ and the\nnonperturbative mass function $M(p)$ for a variety of bare quark masses and\nperform a simple linear extrapolation to the chiral limit. We focus on the\ncomparison of the behavior of $Z(q)$ and $M(p)$ in the chiral limit in the two\ngauge fixing schemes as well as the behavior on two lattices with different\nlattice spacing $a$. We find that the mass functions $M(p)$ are very similar\nfor the two gauges while the wave-function renormalization function $Z(q)$ is\nmore strongly infrared suppressed in the Laplacian gauge than in the Landau\ngauge on the finer lattice. For Laplacian gauge, it seems that the finite $a$\nerror is large on the coarse lattice which has a lattice spacing $a$ of about\n0.124 fm."
    },
    {
        "anchor": "Charm and bottom quark masses on the lattice: Lattice determinations of quark mass have made significant progress in the\nlast few years. I will review recent advances in calculations of charm and\nbottom mass, which are near to achieving percent-level precision and with fully\ncontrolled systematics. Precise knowledge of these parameters is of particular\ninterest for precision Higgs studies at future accelerators.",
        "positive": "Static SU(3) potentials for sources in various representations: The potentials and string tensions between static sources in a variety of\nrepresentations (fundamental, 8, 6, 15-antisymmetric, 10, 27 and 15-symmetric)\nhave been computed by measuring Wilson loops in pure gauge SU(3). The\nsimulations have been done primarily on anisotropic lattices, using a tadpole\nimproved action improved to O(a_{s}^4). A range of lattice spacings (0.43 fm,\n0.25 fm and 0.11 fm) and volumes ($8^3\\times 24$, $10^3 \\times 24$, $16^3\n\\times 24$ and $18^3 \\times 24$) has been used in an attempt to control\ndiscretization and finite volume effects. At intermediate distances, the\nresults show approximate Casimir scaling. Finite lattice spacing effects\ndominate systematic error, and are particularly large for the representations\nwith the largest string tensions."
    },
    {
        "anchor": "Charmonia in moving frames: Lattice simulation of charmonium resonances with non-zero momentum provides\nadditional information on the two-meson scattering matrices. However, the\nreduced rotational symmetry in a moving frame renders a number of states with\ndifferent $J^P$ in the same lattice irreducible representation. The\nidentification of $J^P$ for these states is particularly important, since\nquarkonium spectra contain a number of states with different $J^P$ in a\nrelatively narrow energy region. Preliminary results concerning\nspin-identification are presented in relation to our study of charmonium\nresonances in flight on the Nf=2+1 CLS ensembles.",
        "positive": "Partially quenched QCD and staggered fermions: We summarize results for partially quenched chiral perturbation theory and\nindicate an application to staggered fermion QCD in which the square root of\nthe determinant is taken to reduce the number of flavors from four to two."
    },
    {
        "anchor": "Di-Quarks and Tri-Quarks on the Lattice: The distribution of gluon fields in hadrons is of fundamental interest in\nQCD. Using lattice QCD we have observed the formation of gluon flux tubes\nwithin tri-quark (baryon) systems for a wide variety of spatial distributions\nof the color sources. In particular we have investigated configurations where\ntwo of the quarks are close together and the third quark is some distance away,\nwhich approximates a quark plus diquark string. We find that the string tension\nof the quark-diquark string is the same as that of the quark-antiquark string\non the same lattice. We also compare the longitudinal and transverse profiles\nof the gluon flux tubes for both sets of strings, and find them to be of\nsimilar radii and to have similar vacuum suppression.",
        "positive": "Aggregation-based Multilevel Methods for Lattice QCD: In Lattice QCD computations a substantial amount of work is spent in solving\nthe Dirac equation. In the recent past it has been observed that conventional\nKrylov solvers tend to critically slow down for large lattices and small quark\nmasses. We present a Schwarz alternating procedure (SAP) multilevel method as a\nsolver for the Clover improved Wilson discretization of the Dirac equation.\nThis approach combines two components (SAP and algebraic multigrid) that have\nseparately been used in lattice QCD before. In combination with a bootstrap\nsetup procedure we show that considerable speed-up over conventional Krylov\nsubspace methods for realistic configurations can be achieved."
    },
    {
        "anchor": "Double-winding Wilson loops in SU(N) lattice Yang-Mills gauge theory: We study double-winding Wilson loops in $SU(N)$ lattice Yang-Mills gauge\ntheory by using both strong coupling expansions and numerical simulations.\nFirst, we examine how the area law falloff of a ``coplanar'' double-winding\nWilson loop average depends on the number of color $N$. Indeed, we find that a\ncoplanar double-winding Wilson loop average obeys a novel ``max-of-areas law''\nfor $N=3$ and the sum-of-areas law for $N\\geq 4$, although we reconfirm the\ndifference-of-areas law for $N=2$. Second, we examine a ``shifted''\ndouble-winding Wilson loop, where the two constituent loops are displaced from\none another in a transverse direction. We evaluate its average by changing the\ndistance of a transverse direction and we find that the long distance behavior\ndoes not depend on the number of color $N$, while the short distance behavior\ndepends strongly on $N$.",
        "positive": "Low energy properties of SU(2) gauge theory with N_f = 3/2 flavours of\n  adjoint fermions: In this work we present the results of a numerical investigation of SU(2)\ngauge theory with N_f = 3/2 flavours of fermions, corresponding to 3 Majorana\nfermions, which transform in the adjoint representation of the gauge group. At\ntwo values of the gauge coupling, the masses of bound states are considered as\na function of the fundamental fermion mass, represented by the PCAC quark mass.\nThe scaling of bound states masses indicates an infrared conformal behaviour of\nthe theory. We obtain estimates for the fixed-point value of the mass anomalous\ndimension $\\gamma^{\\ast}$ from the scaling of masses and from the scaling of\nthe mode number of the Wilson-Dirac operator. The difference of the estimates\nat the two gauge couplings should be due to scaling violations and lattice\nspacing effects. The more reliable estimate at the smaller gauge coupling is\n$\\gamma^{\\ast} \\approx 0.38(2)$."
    },
    {
        "anchor": "Ising Model Coupled to Three-Dimensional Quantum Gravity: We have performed Monte Carlo simulations of the Ising model coupled to\nthree-dimensional quantum gravity based on a summation over dynamical\ntriangulations. These were done both in the microcanonical ensemble, with the\nnumber of points in the triangulation and the number of Ising spins fixed, and\nin the grand canoncal ensemble. We have investigated the two possible cases of\nthe spins living on the vertices of the triangulation (``diect'' case) and the\nspins living in the middle of the tetrahedra (``dual'' case). We observed phase\ntransitions which are probably second order, and found that the dual\nimplementation more effectively couples the spins to the quantum gravity.",
        "positive": "Scalar Quarkonium and the Scalar Glueball: Valence approximation glueball mass and decay calculations support the\nidentification of $f_J(1710)$ as the lightest scalar glueball. An alternate\nglueball candidate is $f_0(1500)$. I present evidence for the identification of\n$f_0(1500)$ as $s\\overline{s}$ quarkonium."
    },
    {
        "anchor": "Two pion scattering, I=0 and disconnected diagrams in Lattice QCD: A full, high-statistic I=0 and I=2 $\\pi-\\pi$ scattering calculation including\nthe disconnected diagram is performed on 2+1 flavor, domain wall fermion gauge\nconfigurations generated using the Iwasaki gauge action with $\\beta=2.13$, a\n$16^3\\times32$ volume with $L_s=16$ and $a^{-1}=1.73GeV$. Using the same light\nquark propagators and additional strange quark propagators, we study the $\\eta$\nand $\\eta^\\prime$ mesons, where disconnected diagrams also make an important\ncontribution. Our $\\pi-\\pi$ calculation shows a good exponentially decaying\nsignal from the disconnected graph, which makes a small contribution to the I=0\nscattering amplitude at least for the short times where it can be accurately\ncomputed. We are able to resolve the $\\eta$ and $\\eta^\\prime$ states and see\nthe pattern of SU(3) flavor symmetry breaking found in Nature.",
        "positive": "Electric charge susceptibility in 2+1 flavour QCD on an anisotropic\n  lattice: The FASTSUM Collaboration presents its first results for the electric charge\nsusceptibility in QCD using 2+1 dynamical flavours of Wilson quark on\nanisotropic lattices. Spatial volumes of (2.94 fm)^3 are used at fixed cut-off\nwith temperatures ranging from below T_c to ~2 T_c."
    },
    {
        "anchor": "Thermodynamics in quenched QCD: energy--momentum tensor with two-loop\n  order coefficients in the gradient flow formalism: Recently, Harlander et al.\\ [Eur.\\ Phys.\\ J.\\ C {\\bf 78}, 944 (2018)] have\ncomputed the two-loop order (i.e., NNLO) coefficients in the gradient-flow\nrepresentation of the energy--momentum tensor (EMT) in vector-like gauge\ntheories. In this paper, we study the effect of the two-loop order corrections\n(and the three-loop order correction for the trace part of the EMT, which is\navailable through the trace anomaly) on the lattice computation of\nthermodynamic quantities in quenched QCD. The use of the two-loop order\ncoefficients generally reduces the $t$~dependence of the expectation values of\nthe EMT in the gradient-flow representation, where $t$~is the flow time. With\nthe use of the two-loop order coefficients, therefore, the $t\\to0$\nextrapolation becomes less sensitive to the fit function, the fit range, and\nthe choice of the renormalization scale; the systematic error associated with\nthese factors is considerably reduced.",
        "positive": "Solitons and spontaneous symmetry breaking in 2 and 4 dimensions: We show that mass generation in 1+1 and 3+1 dimensions may occur together\nwith spontaneous symmetry breaking."
    },
    {
        "anchor": "A review on Glueball hunting: One of the most direct predictions of QCD is the existence of color-singlet\nstates called Glueballs, which emerge as a consequence of the gluon field\nself-interactions. Despite the outstanding success of QCD as a theory of the\nstrong interaction and decades of experimental and theoretical efforts, all but\nthe most basic properties of Glueballs are still being debated. In this talk, I\nwill review efforts aimed to understanding Glueballs and the current status of\nGlueball searches, including recent experimental results and lattice\ncalculations.",
        "positive": "Gauge Invariant Effective Action in Abelian Chiral Gauge Theory on the\n  Lattice: L\\\"uscher's recent formulation of Abelian chiral gauge theories on the\nlattice, in the vacuum (or perturbative) sector in infinite volume, is\nreinterpreted in terms of the lattice covariant regularization. The gauge\ninvariance of the effective action and the integrability of the gauge current\nin anomaly-free cases become transparent. The real part of the effective action\nis simply one-half that of the Dirac fermion and, when the Dirac operator\nbehaves properly in the continuum limit, the imaginary part in this limit\nreproduces the $\\eta$-invariant."
    },
    {
        "anchor": "Closed k-strings in SU(N) gauge theories : 2+1 dimensions: We calculate the ground state energies of closed k-strings in\n(2+1)-dimensional SU(N) gauge theories, for N=4,5,6,8 and k=2,3,4. From the\ndependence of the ground state energy on the string length, we infer that such\nk-strings are described by an effective string theory that is in the same\nbosonic universality class (Nambu-Goto) as the fundamental string. When we\ncompare the continuum k-string tensions to the corresponding fundamental string\ntensions, we find that the ratios are close to, but typically 1-2 percent\nabove, the Casimir scaling values favoured by some theoretical approaches.\nFitting the N-dependence in a model-independent way favours an expansion in 1/N\n(as in Casimir scaling) rather than the 1/N^2 that is suggested by naive colour\ncounting. We also observe that the low-lying spectrum of k-string states falls\ninto sectors that belong to particular irreducible representations of SU(N),\ndemonstrating that the dynamics of string binding knows about the full gauge\ngroup and not just about its centre.",
        "positive": "Two-flavor lattice QCD in the epsilon-regime and chiral Random Matrix\n  Theory: The low-lying eigenvalue spectrum of the QCD Dirac operator in the\nepsilon-regime is expected to match with that of chiral Random Matrix Theory\n(ChRMT). We study this correspondence for the case including sea quarks by\nperforming two-flavor QCD simulations on the lattice. Using the overlap fermion\nformulation, which preserves exact chiral symmetry at finite lattice spacings,\nwe push the sea quark mass down to \\sim 3 MeV on a 16^3\\times 32 lattice at a\nlattice spacing a \\simeq 0.11 fm. We compare the low-lying eigenvalue\ndistributions and find a good agreement with the analytical predictions of\nChRMT. By matching the lowest-lying eigenvalue we extract the chiral\ncondensate, \\Sigma(2 GeV)[MSbar] = [251(7)(11) MeV]^3, where errors represent\nstatistical and higher order effects in the epsilon expansion. We also\ncalculate the eigenvalue distributions on the lattices with heavier sea quarks\nat two lattice spacings. Although the epsilon expansion is not applied for\nthose sea quarks, we find a reasonable agreement of the Dirac operator spectrum\nwith ChRMT. The value of Sigma, after extrapolating to the chiral limit, is\nconsistent with the estimate in the epsilon-regime."
    },
    {
        "anchor": "Lattice QCD Equation of State for Nonvanishing Chemical Potential by\n  Resumming Taylor Expansion: Taylor expansion in powers of baryon chemical potential ($\\mu_B$) is an\noft-used method in lattice QCD to compute QCD thermodynamics for $\\mu_B>0$.\nBased only upon the few known lowest order Taylor coefficients, it is difficult\nto discern the range of $\\mu_B$ where such an expansion around $\\mu_B=0$ can be\ntrusted. We introduce a resummation scheme for the Taylor expansion of the QCD\nequation of state in $\\mu_B$ that is based on the $n$-point correlation\nfunctions of the conserved current ($D_n$). The method resums the contributions\nof the first $N$ correlation function $D_1,\\dots,D_N$ to the Taylor expansion\nof the QCD partition function to all orders in $\\mu_B$. We show that the\nresummed partition function is an approximation to the reweighted partition\nfunction at $\\mu_B\\ne0$. We apply the proposed approach to high-statistics\nlattice QCD calculations using 2+1 flavors of Highly Improved Staggered Quarks\nwith physical quark masses on $32^3\\times8$ lattices and for temperatures\n$T\\approx145$-176 MeV. We demonstrate that, as opposed to the Taylor expansion,\nthe resummed version not only leads to improved convergence but also reflects\nthe zeros of the resummed partition function and severity of the sign problem,\nleading to its eventual breakdown. We also provide a generalization of our\nscheme to include resummation of powers of temperature and quark masses in\naddition to $\\mu_B$, and show that the alternative expansion scheme of [S.\nBors\\'anyi et al., Phys. Rev. Lett. 126, 232001 (2021).] is a special case of\nthis generalized resummation.",
        "positive": "The two flavour Schwinger model: scaling of the scalar condensate: We investigate the continuum limit scaling of the scalar condensate in the\n$N_f=2$ Schwinger model on the lattice. We employ maximally twisted mass Wilson\nfermions and overlap fermions. We compute the scalar condensate by taking the\ntrace of the propagator (direct method) and by utilizing the integrated\nWard-Takahashi identity. While the scalar condensate comes out consistent using\nthese two methods for a given kind of lattice fermions, we find --quite\nsurprisingly-- large discrepancies for the scalar condensate between twisted\nmass and overlap fermions. These discrepancies are only resolved when using the\npoint split current for twisted mass fermions."
    },
    {
        "anchor": "Roberge-Weiss endpoint and chiral symmetry restoration in $N_f = 2+1$\n  QCD: We investigate the fate of the Roberge-Weiss endpoint transition and its\nconnection with the restoration of chiral symmetry as the chiral limit of $N_f\n= 2+1$ QCD is approached. We adopt a stout staggered discretization on lattices\nwith $N_t = 4$ sites in the temporal direction; the chiral limit is approached\nmaintaining a constant physical value of the strange-to-light mass ratio and\nexploring three different light quark masses, corresponding to pseudo-Goldstone\npion masses $m_\\pi \\simeq 100, 70$ and 50 MeV around the transition. A finite\nsize scaling analysis provides evidence that the transition remains second\norder, in the 3D Ising universality class, in all the explored mass range. The\nresidual chiral symmetry of the staggered action also allows us to investigate\nthe relation between the Roberge-Weiss endpoint transition and the chiral\nrestoration transition as the chiral limit is approached: our results,\nincluding the critical scaling of the chiral condensate, are consistent with a\ncoincidence of the two transitions in the chiral limit; however we are not able\nto discern the symmetry controlling the critical behavior, because the critical\nindexes relevant to the scaling of the chiral condensate are very close to each\nother for the two possible universality classes (3D Ising or O(2)).",
        "positive": "Periodic vacuum and particles in two dimensions: Different dynamical symmetry breaking patterns are explored for the two\ndimensional phi4 model with higher order derivative terms. The one-loop saddle\npoint expansion predicts a rather involved phase structure and a new Gaussian\ncritical line. This vacuum structure is corroborated by the Monte Carlo method,\nas well. Analogies with the structure of solids, the density wave phases and\nthe effects of the quenched impurities are mentioned. The unitarity of the time\nevolution operator in real time is established by means of the reflection\npositivity."
    },
    {
        "anchor": "Analysis of systematic errors in the calculation of renormalization\n  constants of the topological susceptibility on the lattice: A Ginsparg-Wilson based calibration of the topological charge is used to\ncalculate the renormalization constants which appear in the field-theoretical\ndetermination of the topological susceptibility on the lattice. A systematic\ncomparison is made with calculations based on cooling. The two methods agree\nwithin present statistical errors (3%-4%). We also discuss the independence of\nthe multiplicative renormalization constant Z from the background topological\ncharge used to determine it.",
        "positive": "Two Loop Partially Quenched and Finite Volume Chiral Perturbation Theory\n  Results: This talk presents some results relevant for lattice QCD at higher order in\nChPT. First we discuss the finite volume corrections at two loops for the quark\ncondensate as well as a L\\\"uscherlike finite volume formula for it. The latter\nallows for an alternative determination of meson sigma terms. The second set of\nresults presented here are the calculations at two loops in partially quenched\nchiral perturbation theory of masses and decay constants of the charged mesons.\nWe present results for all relevant quark mass combinations for the cases with\ntwo and three sea quarks."
    },
    {
        "anchor": "Staggered chiral perturbation theory in the two-flavor case and SU(2)\n  analysis of the MILC data: In the light pseudoscalar sector, we study rooted staggered chiral\nperturbation theory in the two-flavor case. The pion mass and decay constant\nare calculated through NLO for a partially-quenched theory. In the limit where\nthe strange quark mass is large compared to the light quark masses and the\ntaste splittings, we show that the SU(2) staggered chiral theory emerges from\nthe SU(3) staggered chiral theory, as expected. Explicit relations between\nSU(2) and SU(3) low energy constants and taste-violating parameters are given.\nA brief summary of updated SU(2) chiral fits to the MILC lattice data is\npresented.",
        "positive": "Condensation of vortices and disorder parameter in 3d Heisenberg model: The 3d Heisenberg model is studied from a dual point of view. It is shown\nthat the disordered phase corresponds to condensation of vortices in the\nvacuum, and the critical indices are computed from the corresponding disorder\nparameter."
    },
    {
        "anchor": "Four Loop Result in $SU(3)$ Lattice Gauge Theory by a Stochastic Method:\n  Lattice Correction to the Condensate: We describe a stochastic technique which allows one to compute numerically\nthe coefficients of the weak coupling perturbative expansion of any observable\nin Lattice Gauge Theory. The idea is to insert the exponential representation\nof the link variables $U_\\mu(x) \\to \\exp\\{A_\\mu(x)/\\sqrt\\beta\\}$ into the\nLangevin algorithm and the observables and to perform the expansion in\n\\beta^{-1/2}. The Langevin algorithm is converted into an infinite hierarchy of\nmaps which can be exactly truncated at any order. We give the result for the\nsimple plaquette of SU(3) up to fourth loop order (\\beta^{-4}) which extends by\none loop the previously known series.",
        "positive": "Topological Properties of the QCD Vacuum at T=0 and T ~ T_c: We study on the lattice the topology of SU(2) and SU(3) Yang-Mills theories\nat zero temperature and of QCD at temperatures around the phase transition. To\nsmooth out dislocations and the UV noise we cool the configurations with an\naction which has scale invariant instanton solutions for instanton size above\nabout 2.3 lattice spacings. The corresponding \"improved\" topological charge\nstabilizes at an integer value after few cooling sweeps. At zero temperature\nthe susceptibility calculated from this charge (about (195MeV)^4 for SU(2) and\n(185 MeV)^4 for SU(3)) agrees very well with the phenomenological expectation.\nAt the minimal amount of cooling necessary to resolve the structure in terms of\ninstantons and anti-instantons we observe a dense ensemble where the total\nnumber of peaks is by a factor 5-10 larger than the net charge. The average\nsize observed for these peaks at zero temperature is about 0.4-0.45 fm for\nSU(2) and 0.5-0.6 fm for SU(3). The size distribution changes very little with\nfurther cooling, although in this process up to 90% of the peaks disappear by\npair annihilation. For QCD we observe below T_c a reduction of the topological\nsusceptibility as an effect of the dynamical fermions. Nevertheless also here\nthe instantons form a dense ensemble with general characteristics similar to\nthose of the quenched theory. A further drop in the susceptibility above T_c is\nalso in rough agreement with what has been observed for pure SU(3). We see no\nclear signal for dominant formation of instanton - anti-instanton molecules."
    },
    {
        "anchor": "Nucleon axial form factors using lattice QCD simulations with a physical\n  value of the pion mass: We present results on the nucleon axial and induced pseudo-scalar form\nfactors using an ensemble of two degenerate twisted mass clover-improved\nfermions generated at the physical value of the pion mass. We evaluate the\nisovector and the isoscalar, as well as, the strange and the charm axial form\nfactors. The disconnected contributions are evaluated using recently developed\nmethods that include deflation of the lower eigenstates, allowing us to extract\nthe isoscalar, strange and charm axial form factors. We find that the\ndisconnected quark loop contributions are non-zero and particularly large for\nthe induced pseudo-scalar form factor.",
        "positive": "Abelian dominance and gluon propagators in the Maximally Abelian gauge\n  of SU(2) lattice gauge theory: Propagators of the diagonal and the off-diagonal gluons are studied\nnumerically in the Maximal Abelian gauge of SU(2) lattice gauge theory. It is\nfound that in the infrared region the propagator of the diagonal gluon is\nstrongly enhanced in comparison with the off--diagonal one. The enhancement\nfactor is about 50 at our smallest momentum 325 MeV. We have also applied\nvarious fits to the propagator formfactors."
    },
    {
        "anchor": "Low-lying spectrum for lattice Dirac operators with twisted mass: We analyze the low-lying spectrum and eigenmodes of lattice Dirac operators\nwith a twisted mass term. The twist term expels the eigenvalues from a strip in\nthe complex plane and all eigenmodes obtain a non-vanishing matrix element with\ngamma-5. For a twisted Ginsparg-Wilson operator the spectrum is located on two\narcs in the complex plane. Modes due to non-trivial topological charge of the\nunderlying gauge field have their eigenvalues at the edges of these arcs and\nobey a remnant index theorem. For configurations in the confined phase we find\nthat the twist mainly affects the zero modes, while the bulk of the spectrum is\nessentially unchanged.",
        "positive": "The staggered domain wall fermion method: A different lattice fermion method is introduced. Staggered domain wall\nfermions are defined in 2n+1 dimensions and describe 2^n flavors of light\nlattice fermions with exact U(1) x U(1) chiral symmetry in 2n dimensions. As\nthe size of the extra dimension becomes large, 2^n chiral flavors with the same\nchiral charge are expected to be localized on each boundary and the full\nSU(2^n) x SU(2^n) flavor chiral symmetry is expected to be recovered. SDWF give\na different perspective into the inherent flavor mixing of lattice fermions and\nby design present an advantage for numerical simulations of lattice QCD\nthermodynamics. The chiral and topological index properties of the SDWF Dirac\noperator are investigated. And, there is a surprise ending..."
    },
    {
        "anchor": "Non-equilibrium study of the Chiral Magnetic Effect from real-time\n  simulations with dynamical fermions: We present a real-time lattice approach to study the non-equilibrium dynamics\nof vector and axial charges in $SU(N) \\times U(1)$ gauge theories. Based on a\nclassical description of the non-Abelian and Abelian gauge fields, we include\ndynamical fermions and develop operator definitions for (improved) Wilson and\noverlap fermions that allow us to study real-time manifestations of the axial\nanomaly from first principles. We present a first application of this approach\nto anomalous transport phenomena such as the Chiral Magnetic Effect (CME) and\nChiral Separation Effect (CSE) by studying the dynamics of fermions during and\nafter a $SU(N)$ sphaleron transition in the presence of a $U(1)$ magnetic\nfield. We investigate the fermion mass and magnetic field dependence of the\nsuggested signatures of the CME and CSE and point out some important aspects\nwhich need to be accounted for in the macroscopic description of anomalous\ntransport phenomena.",
        "positive": "Fast Evaluation of Multi-Hadron Correlation Functions: Calculating the values of nuclear correlation functions is computationally\nintensive due to the fact that the number of terms in a nuclear wave function\nscales exponentially with atomic number. To speed up this computation, we\nrepresent a correlation function as a sum of the determinants of many small\nmatrices, and exploit similarities between the matrices to speed up the\ncalculations of those determinants."
    },
    {
        "anchor": "Status of 2+1 flavor, 32^3x64 domain wall fermion simulations: We describe details of 1/a ~ 2.2Gev, L ~ 3 fm dynamical domain wall fermion\nsimulations which will allow us to do a more systematic continuum extrapolation\nin combination with existing simu- lations. Details of the simulations such as\nalgorithm choices and machine performance, as well as results of basic\nmeasurements are presented. These configurations are presently being generated\non the QCDOC machine at Edinburgh and the DOE QCDOC machine at Brookhaven as\npart of a joint project with LHPC.",
        "positive": "Two-Dimensional Compact N=(2,2) Lattice Super Yang-Mills Theory with\n  Exact Supersymmetry: We construct two-dimensional N=(2,2) lattice super Yang-Mills theory, where\nthe gauge and Higgs fields are all represented by U(N) compact variables, with\nkeeping one exact supercharge along the line of the papers [1,2,3].\nInterestingly, requirements of the exact supersymmetry as well as of the\ncompact gauge and Higgs fields lead to the gauge group U(N) rather than SU(N).\nAs a result of the perturbative renormalization argument, the model is shown to\nflow to the target continuum theory without any fine-tuning. Different from the\ncase of noncompact Higgs fields, the path integral along the flat directions is\nwell-defined in this model."
    },
    {
        "anchor": "Model independent approach to studies of the confining dual Abrikosov\n  vortex in SU(2) lattice gauge theory: We address the problem of determining the type I, type II or borderline dual\nsuperconductor behavior in maximal Abelian gauge SU(2) through the study of the\ndual Abrikosov vortex. We find that significant electric currents in the\nsimulation data call into question the use of the dual Ginzburg Landau Higgs\nmodel in interpreting the data. Further, two definitions of the penetration\ndepth parameter take two different values. The splitting of this parameter into\ntwo is intricately connected to the existence of electric currents. It is\nimportant in our approach that we employ definitions of flux and electric and\nmagnetic currents that respect Maxwell equations exactly for lattice averages\nindependent of lattice spacings. Applied to specific Wilson loop sizes, our\nconclusions differ from those that use the dual GLH model.",
        "positive": "N* Spectroscopy from Lattice QCD: The Roper Explained: This brief review focuses on the low-lying even- and odd-parity excitations\nof the nucleon obtained in recent lattice QCD calculations. Commencing with a\nsurvey of the 2014-15 literature we'll see that results for the first\neven-parity excitation energy can differ by as much as 1 GeV, a rather\nunsatisfactory situation. Following a brief review of the methods used to\nisolate excitations of the nucleon in lattice QCD, and drawing on recent\nadvances, we'll see how a consensus on the low-lying spectrum has emerged among\nmany different lattice groups. To provide insight into the nature of these\nstates we'll review the wave functions and electromagnetic form factors that\nare available for a few of these states. Consistent with the Luscher formalism\nfor extracting phase shifts from finite volume spectra, the Hamiltonian\napproach to effective field theory in finite volume can provide guidance on the\nmanner in which physical quantities manifest themselves in the finite volume of\nthe lattice. With this insight, we will address the question; Have we seen the\nRoper in lattice QCD?"
    },
    {
        "anchor": "Quenched Finite Volume Logarithms: Quenched chiral perturbation theory is used to compute the first finite\nvolume correction to the chiral condensate. The correction diverges\nlogarithmically with the four-volume $V$. We point out that with dynamical\nquarks one can obtain both the chiral condensate and the pion decay constant\nfrom the distributions of the lowest Dirac operator eigenvalues.",
        "positive": "Strong Isospin Breaking in the Nucleon and Delta Masses on the Lattice: Strong isospin breaking in the spectrum of the nucleons and deltas can be\nstudied in lattice QCD with the help of chiral perturbation theory. At leading\norder in the chiral expansion, the mass splittings between the proton and\nneutron and between the deltas are linear in the quark mass difference. The\nnext-to-leading order contributions to these splittings vanish even away from\nthe strong-isospin limit. Therefore, any non-linear quark mass dependence of\nthese mass splittings is a signal of the next-to-next-to-leading order mass\ncontributions, thus providing access to LECs at this order. We determine the\nmass splittings of the nucleons and deltas in two-flavor, heavy baryon chiral\nperturbation theory to next-to-next-to-leading order. We also derive\nexpressions for the nucleon and delta masses in partially quenched chiral\nperturbation theory to the same order. The resulting mass expressions will be\nuseful both for the extrapolation of lattice data on baryon masses, and for the\nstudy of strong isospin breaking."
    },
    {
        "anchor": "Quark masses and strong CP violation: Two flavor QCD involves three independent mass parameters for which\nnon-perturbative effects are not universal. This precludes matching lattice and\nperturbative results for non-degenerate quarks and eliminates a vanishing up\nquark mass as a viable solution to the strong CP problem.",
        "positive": "Topology on the Lattice: We review the method developed in Pisa to determine the topological\nsusceptibility in lattice QCD and present a collection of new and old results\nobtained by the method."
    },
    {
        "anchor": "Speeding up HMC with better integrators: We discuss how dynamical fermion computations may be made yet cheaper by\nusing symplectic integrators that conserve energy much more accurately without\ndecreasing the integration step size. We first explain why symplectic\nintegrators exactly conserve a ``shadow'' Hamiltonian close to the desired one,\nand how this Hamiltonian may be computed in terms of Poisson brackets. We then\ndiscuss how classical mechanics may be implemented on Lie groups and derive the\nform of the Poisson brackets and force terms for some interesting integrators\nsuch as those making use of second derivatives of the action (Hessian or force\ngradient integrators). We hope that these will be seen to greatly improve\nenergy conservation for only a small additional cost and that their use will\nsignificantly reduce the cost of dynamical fermion computations.",
        "positive": "Dual quark condensate and dressed Polyakov loops: We construct a new order parameter for finite temperature QCD by considering\nthe quark condensate for U(1)-valued temporal boundary conditions for the\nfermions. Fourier transformation with respect to the boundary condition defines\nthe dual condensate. This quantity corresponds to an equivalence class of\nPolyakov loops, thereby being an order parameter for the center symmetry. We\nexplore the duality relation between the quark condensate and these dressed\nPolyakov loops numerically, using quenched lattice QCD configurations below and\nabove the QCD phase transition. It is demonstrated that the Dirac spectrum\nresponds differently to changing the boundary condition, in a manner that\nreproduces the expected Polyakov loop pattern. We find the dressed Polyakov\nloops to be dominated by the lowest Dirac modes, in contrast to thin Polyakov\nloops investigated earlier."
    },
    {
        "anchor": "Proposal for the Quantum Simulation of the CP(2) Model on Optical\n  Lattices: The 2d CP(N-1) models share a number of features with QCD, like asymptotic\nfreedom, a dynamically generated mass gap and topological sectors. They have\nbeen formulated and analysed successfully in the framework of the so-called\nD-theory, which provides a smooth access to the continuum limit. In that\nframework, we propose an experimental set-up for the quantum simulation of the\nCP(2) model. It is based on ultra-cold Alkaline-Earth Atoms (AEAs) located on\nthe sites of an optical lattice, where the nuclear spins represent the relevant\ndegrees of freedom. We present numerical results for the correlation length and\nfor the real time decay of a false vacuum, to be compared with such a future\nexperiment. The latter could also enable the exploration of theta-vacua and of\nthe phase diagram at finite chemical potentials, since it does not suffer from\nany sign problem.",
        "positive": "Exploring quark transverse momentum distributions with lattice QCD: We discuss in detail a method to study transverse momentum dependent parton\ndistribution functions (TMDs) using lattice QCD. To develop the formalism and\nto obtain first numerical results, we directly implement a bi-local quark-quark\noperator connected by a straight Wilson line, allowing us to study T-even,\n\"process-independent\" TMDs. Beyond results for x-integrated TMDs and quark\ndensities, we present a study of correlations in x and transverse momentum. Our\ncalculations are based on domain wall valence quark propagators by the LHP\ncollaboration calculated on top of gauge configurations provided by MILC with\n2+1 flavors of asqtad-improved staggered sea quarks."
    },
    {
        "anchor": "Remarks on strange-quark simulations with Wilson fermions: In the simulation of QCD with 2+1 flavors of Wilson fermions, the positivity\nof the fermion determinant is generally assumed. We present evidence that this\nassumption is in general not justified and discuss the consequences of this\nfinding.",
        "positive": "Light Quark Masses with $N_f=2$ Wilson Fermions: We present new data on the mass of the light and strange quarks from\nSESAM/T$\\chi$L. The results were obtained on lattice-volumes of $16^3\\times 32$\nand $24^3\\times 40$ points, with the possibility to investigate finite-size\neffects. Since the SESAM/T$\\chi$L ensembles at $\\beta=5.6$ have been\ncomplemented by configurations with $\\beta=5.5$, moreover, we are now able to\nattempt the continuum extrapolation (CE) of the quark masses with standard\nWilson fermions."
    },
    {
        "anchor": "Induced representations of Poincare group on the lattice: spin 1/2 and 1\n  case: Following standard methods we explore the construction of the discrete\nPoincare group, the semidirect product of discrete translations and integral\nLorentz transformations, using the Wigner-Mackey construction restricted to the\nmomentum and position space on the lattice. The orbit condition, irreducibility\nand assimptotic limit are discussed.",
        "positive": "Solving DWF Dirac Equation Using Multisplitting Preconditioned Conjugate\n  Gradient: We show that using the multisplitting algorithm as a preconditioner for\nconjugate gradient inversion of the domain wall Dirac operator could\neffectively reduce the inter- node communication cost, at the expense of\nperforming more on-node floating point operations. This method could be useful\nfor supercomputers with far more on-node flops than inter-node communication\nbandwidth."
    },
    {
        "anchor": "Study of 3-flavor QCD Finite Temperature Phase Transition with Staggered\n  Fermions: We have studied the 3-flavor, finite temperature, QCD phase transition with\nstaggred fermions on an $ N_t=4$ lattice. By studying a variety of quark masses\nwe have located the critical point, $m_c$, where the first order 3-flavor\ntransition ends as lying in the region $0.32 \\le m_c \\le 0.35$ in lattice units",
        "positive": "Properties of U(1) lattice gauge theory with monopole term: In 4D compact U(1) lattice gauge theory with a monopole term added to the\nWilson action we first reveal some properties of a third phase region at\nnegative $\\beta$. Then at some larger values of the monopole coupling $\\lambda$\nby a finite-size analysis we find values of the critical exponent $\\nu$ close\nto, however, different from the Gaussian value."
    },
    {
        "anchor": "Light Meson Physics from Maximally Twisted Mass Lattice QCD: We present a comprehensive investigation of light meson physics using\nmaximally twisted mass fermions for two mass-degenerate quark flavours. By\nemploying four values of the lattice spacing, spatial lattice extents ranging\nfrom 2.0 fm to 2.5 fm and pseudo scalar masses in the range 280 MeV to 650 MeV\nwe control the major systematic effects of our calculation. This enables us to\nconfront our data with chiral perturbation theory and extract low energy\nconstants of the effective chiral Lagrangian and derived quantities, such as\nthe light quark mass, with high precision.",
        "positive": "The Finite Temperature Phase Diagram of a U(1) Higgs-Yukawa Model: The finite temperature phase diagram of a U(1) Higgs-Yukawa model at a finite\nvalue of the scalar self coupling $\\lambda$ is investigated by means of a\nlarge-$N_f$ calculation and numerical simulations. The phase diagram is similar\nto the one at zero temperature and shows a ferromagnetic, two symmetric and an\nantiferromagnetic phase. However, the phase transition lines are shifted to\nlarger values of the Yukawa coupling demonstrating the occurence of the finite\ntemperature symmetry restoration."
    },
    {
        "anchor": "Lattice QCD at finite temperature and density in the phase-quenched\n  approximation: QCD at a finite quark-number chemical potential $\\mu$ has a complex fermion\ndeterminant, which precludes its study by standard lattice QCD simulations. We\ntherefore simulate lattice QCD at finite $\\mu$ in the phase-quenched\napproximation, replacing the fermion determinant with its magnitude. These\nsimulations are used to study the finite temperature transition for small\n$\\mu$,where the position and nature of this transition are expected to be\nunchanged by this approximation. We look for the expected critical endpoint for\n3-flavour QCD. Here, it had been argued that the critical point at zero $\\mu$\nwould become the critical endpoint at small $\\mu$, for quark masses just above\nthe critical mass. Our simulations indicate that this does not happen, and\nthere is no such critical endpoint for small $\\mu$. We discuss how we might\nadapt techniques used for imaginary $\\mu$ to improve the signal/noise ratio and\nstrengthen our conclusions, using results from relatively low statistics\nstudies.",
        "positive": "Chiral Limit of Staggered Fermions at Strong Couplings: A Loop\n  Representation: The partition function of two dimensional massless staggered fermions\ninteracting with U(N) gauge fields is rewritten in terms of loop variables in\nthe strong coupling limit. We use this representation of the theory to devise a\nnon-local Metropolis algorithm to calculate the chiral susceptibility. For\nsmall lattices our algorithm reproduces exact results quite accurately.\nApplying this algorithm to large volumes yields rather surprising results. In\nparticular we find $m_\\pi \\neq 0$ for all $N$ and it increases with $N$. Since\nthe talk was presented we have found reasons to believe that our algorithm\nbreaks down for large volumes questioning the validity of our results."
    },
    {
        "anchor": "Complex Langevin calculations in QCD at finite density: We demonstrate that the complex Langevin method (CLM) enables calculations in\nQCD at finite density in a parameter regime in which conventional methods, such\nas the density of states method and the Taylor expansion method, are not\napplicable due to the severe sign problem. Here we use the plaquette gauge\naction with $\\beta = 5.7$ and four-flavor staggered fermions with degenerate\nquark mass $m a = 0.01$ and nonzero quark chemical potential $\\mu$. We confirm\nthat a sufficient condition for correct convergence is satisfied for $\\mu /T =\n5.2 - 7.2$ on a $8^3 \\times 16$ lattice and $\\mu /T = 1.6 - 9.6$ on a $16^3\n\\times 32$ lattice. In particular, the expectation value of the quark number is\nfound to have a plateau with respect to $\\mu$ with the height of 24 for both\nlattices. This plateau can be understood from the Fermi distribution of quarks,\nand its height coincides with the degrees of freedom of a single quark with\nzero momentum, which is 3 (color) $\\times$ 4 (flavor) $\\times$ 2 (spin) $=24$.\nOur results may be viewed as the first step towards the formation of the Fermi\nsphere, which plays a crucial role in color superconductivity conjectured from\neffective theories.",
        "positive": "Targeting the Conformal Window: Scalars on the Lattice: The light Higgs boson of the Standard Model could arise as the consequence of\nthe weakly broken conformal symmetry in a strongly interacting gauge theory.\nHere we present a novel idea to study the transition from conformal to\nconfining behavior using an SU(3) gauge theory with four light and eight heavy\nflavors. This system interpolates between the 12-flavor conformal and the 4\nflavor chirally broken theory as the mass of the heavy flavors are varied. We\nshow first results on our determination of the iso-singlet 0++ state."
    },
    {
        "anchor": "Minimal Doubling Fermion and Hermiticity: We analyze the lattice fermion kinetic term using PT symmetry, R-hermiticity,\nand $\\gamma_{5}$-hermiticity. R-hermiticity is a condition for Hermite action\nand it is related to $\\gamma_{5}$-hermiticity and PT symmetry. Assuming that a\ntranslation-invariant kinetic term with continuum and periodic function does\nnot have PT symmetry, it can have R-hermiticity or $\\gamma_{5}$-hermiticity. We\nprove that a kinetic term with continuum and periodic function that is PT\nsymmetric does not reduce doublers. As a simple example, we analyze the\ntwo-dimensional two-flavor Gross-Neveu model with minimal doubling fermions.\nThe minimal doubling fermions break PT symmetry and R-hermiticity, hence\ncomplex or non-Hermite coupling constants are caused by quantum correction.",
        "positive": "Block spin transformation on the dual lattice and monopole action: To find a perfect lattice action in terms of monopole action on the dual\nlattice, we performed simulations of a monopole effective action obtained\nnumerically from vacuum configurations in SU(2) QCD. Although the Polyakov loop\nbehavior near $T_c$ is well reproduced by the action, a small but repulsive\nterm is needed in addition to get the string tension correctly. It is reported\nalso a monopole effective action in $SU(3)$ QCD which is expressed by one kind\nof monopole currents."
    },
    {
        "anchor": "The k-th Smallest Dirac Operator Eigenvalue and the Pion Decay Constant: We derive an analytical expression for the distribution of the k-th smallest\nDirac eigenvalue in QCD with imaginary isospin chemical potential in the Dirac\noperator. Because of its dependence on the pion decay constant F through the\nchemical potential in the epsilon-regime of chiral perturbation theory this can\nbe used for lattice determinations of that low-energy constant. On the\ntechnical side we use a chiral Random-Two Matrix Theory, where we express the\nk-th eigenvalue distribution through the joint probability of the ordered k\nsmallest eigenvalues. The latter can be computed exactly for finite and\ninfinite N, for which we derive generalisations of Dyson's integration Theorem\nand Sonine's identity.",
        "positive": "Form factors for $\\mathrm B_\\mathrm s \\to \\mathrm K \\ell \u03bd$ decays in\n  Lattice QCD: We present the current status of the computation of the form factor $f_+\n(q^2)$ for the semi-leptonic decay $\\mathrm B_\\mathrm s \\to \\mathrm K \\ell \\nu$\nby the ALPHA collaboration. We use gauge configurations which were generated as\npart of the Coordinated Lattice Simulations (CLS) effort. They have $N_\\mathrm\nf=2$ non-perturbatively $O(a)$ improved Wilson fermions, and pion masses down\nto $\\approx 250 \\,\\mathrm {MeV}$ with $m_\\pi L \\geq 4$. The heavy quark is\ntreated in non-perturbative Heavy Quark Effective Theory (HQET).\n  We discuss how to extract the form factors from the correlation functions and\npresent first results for the form factor at $q^2 = 21.23\\,\\mathrm{GeV}^2$\nextrapolated to the continuum. Next-to-leading order terms in HQET and the\nchiral extrapolation still need to be included in the analysis."
    },
    {
        "anchor": "Chaotic behavior of confining lattice gauge field configurations: We analyze the leading Lyapunov exponents of SU(2) Yang-Mills field\nconfigurations on the lattice which are initialized by quantum Monte Carlo\nsimulations.\n  We find that configurations in the strong coupling phase at finite\ntemperature are substantially more chaotic than in deconfinement.",
        "positive": "Coexistence of monopoles and instantons for different topological charge\n  definitions and lattice actions: We compute instanton sizes and study correlation functions between instantons\nand monopoles in maximum abelian projection within SU(2) lattice QCD at finite\ntemperature. We compare several definitions of the topological charge,\ndifferent lattice actions and methods of reducing quantum fluctuations. The\naverage instanton size turns out to be $\\sigma \\approx 0.2$ fm. The correlation\nlength between monopoles and instantons is $\\zeta \\approx 0.25$ fm and hardly\naffected by lattice artifacts as dislocations. We visualize several specific\ngauge field configurations and show directly that there is an enhanced\nprobability for finding monopole loops in the vicinity of instantons. This\nfeature is independent of the topological charge definition used."
    },
    {
        "anchor": "Gluon Propagator in the Landau Gauge fixed Lattice QCD Simulation: We measured the gluon propagator in the Landau gauge fixed QCD Langevin\nsimulation and studied the infra-red behaviour of the gluon propagator. The 4^3\nx 8 lattice simulation was done for quenched $\\beta=3,4,5$ and unquenched\n$\\beta=4, \\kappa=0.1,0.15,0.2$ using each 100 independent samples. The Landau\ngauge fixing was done by an extension of the Fourier acceleration method with\nthe condition Max|div A|<10^{-4}, and the field A is related to the link\nvariable by U=exp A instead of the usual U-linear definition. We confirmed\ngauge fixing with smearing preconditioning works perfectly for the purpose of\nfinding the global minimum of the squared norm of the gauge field when $\\beta$\nis large(e.g. $\\beta=5$). Our simulation results suggests the possibility of a\nrealization of the infrared behaviour of the Gribov-Zwanziger theory.",
        "positive": "Progress on the QCD deconfinement critical point for $N_\\text{f}=2$\n  staggered fermions: The global center symmetry of quenched QCD at zero baryonic chemical\npotential is broken spontaneously at a critical temperature $T_c$ leading to a\nfirst-order phase transition. Including heavy dynamical quarks breaks the\ncenter symmetry explicitly and weakens the first-order phase transition for\ndecreasing quark masses until it turns into a smooth crossover at a\n$Z(2)$-critical point. We investigate the $Z(2)$-critical quark mass value\ntowards the continuum limit for $N_\\text{f}=2$ flavors using lattice QCD in the\nstaggered formulation. As part of a continued study, we present results from\nMonte-Carlo simulations on $N_\\tau=8,10$ lattices. Several aspect ratios and\nquark mass values were simulated in order to obtain the critical mass from a\nfit of the Polyakov loop to a kurtosis finite size scaling formula. Moreover,\nthe possibility to develop a Ginzburg-Landau effective theory around the\n$Z(2)$-critical point is explored."
    },
    {
        "anchor": "Magnetic Monopoles in non-compact QED - is there a Phase Transition?: The existence of the monopole condensation transition reported by\n  Kocic et al. in non-compact, quenched QED is tested. No phase transition is\nfound. This shows that divergence of the `monopole susceptibility' introduced\nby Hands and Wensley is not a reliable indicator of second order phase\ntransitions. In view of these results\n  I discuss claims that the chiral phase transition seen in QED with fermions\nis a lattice artefact driven by monopole condensation.",
        "positive": "Path optimization in 0+1 dimensional QCD at finite density: We investigate the sign problem in 0+1 dimensional QCD at finite chemical\npotential by using the path optimization method. The SU(3) link variable is\ncomplexified to the SL(3,$\\mathbb{C}$) link variable, and the integral path is\nrepresented by a feedforward neural network. The integral path is then\noptimized to weaken the sign problem. The average phase factor is enhanced to\nbe greater than 0.99 on the optimized path. Results with and without\ndiagonalized gauge fixing are compared and proven to be consistent. This is the\nfirst step of applying the path optimization method to gauge theories."
    },
    {
        "anchor": "Heavy Quarkonia from Anisotropic and Isotropic Lattices: We report on recent results for the spectrum of heavy quarkonia. Using coarse\nand anisotropic lattices we achieved an unprecedented control over statistical\nand systematic errors for higher excited states such as exotic hybrid states.\nIn a parallel study on isotropic lattices we also investigate the effect of two\ndynamical flavours on the spin structure of charmonium and bottomonium for\nseveral symmetric lattices.",
        "positive": "Randomness on the Lattice: In this lecture we review recent lattice QCD studies of the statistical\nproperties of the eigenvalues of the QCD Dirac operator. We find that the\nfluctuations of the smallest Dirac eigenvalues are described by chiral Random\nMatrix Theories with the global symmetries of the QCD partition function.\nDeviations from chiral Random Matrix Theory beyond the Thouless energy can be\nunderstood analytically by means of partially quenched chiral perturbation\ntheory."
    },
    {
        "anchor": "The SU(3) deconfining phase transition with Symanzik action: We report on the determination of the deconfining temperature in SU(3) pure\ngauge theory, using the Symanzik tree level improved action, on lattices of\nsize 3 x 12^3, 4 x 16^3, 5 x 20^3, 6 x24^3. We find that the asymptotic scaling\nviolation pattern is similar to the one observed using the Wilson action. We\nconclude that the irrelevant operators do not affect, in the range of couplings\nconsidered, the lattice beta function. An analysis based on an effective\ncoupling formulation shows an apparent improvement.",
        "positive": "The inverted XY universality of the superconductivity phase transition: It has been conjectured that the phase transition in the Ginzburg-Landau\ntheory is dual to the XY model transition. We study numerically a particular\nlimit of the GL theory where this duality becomes exact, clarifying some of the\nproblems encountered in standard GL theory simulations. This may also explain\nthe failure of the superconductor experiments to observe the XY model scaling."
    },
    {
        "anchor": "Precision study of critical slowing down in lattice simulations of the\n  CP^{N-1} model: With the aim of studying the relevance and properties of critical slowing\ndown in Monte Carlo simulations of lattice quantum field theories we carried\nout a high precision numerical study of the discretised two-dimensional\nCP^{N-1} model at N=10 using an over-heat bath algorithm. We identify critical\nslowing down in terms of slowly-evolving topological modes and present evidence\nthat other observables couple to these slow modes. This coupling is found to\nreduce however as we increase the physical volume in which we simulate.",
        "positive": "Bilocal Dynamics for Self-Avoiding Walks: We introduce several bilocal algorithms for lattice self-avoiding walks that\nprovide reasonable models for the physical kinetics of polymers in the absence\nof hydrodynamic effects. We discuss their ergodicity in different confined\ngeometries, for instance in strips and in slabs. A short discussion of the\ndynamical properties in the absence of interactions is given."
    },
    {
        "anchor": "O(a^2) corrections to the propagator and bilinears of Wilson / clover\n  fermions: We present the corrections to the fermion propagator, to second order in the\nlattice spacing, O(a^2), in 1-loop perturbation theory. The fermions are\ndescribed by the clover action and for the gluons we use a 3-parameter family\nof Symanzik improved actions. Our calculation has been carried out in a general\ncovariant gauge. The results are provided as a polynomial of the clover\nparameter, and are tabulated for 10 popular sets of the Symanzik coefficients\n(Plaquette, Tree-level Symanzik, Iwasaki, TILW and DBW2 action).\n  We also study the O(a^2) corrections to matrix elements of fermion bilinear\noperators that have the form $\\bar\\Psi\\Gamma\\Psi$, where $\\Gamma$ denotes all\npossible distinct products of Dirac matrices. These correction terms are\nessential ingredients for improving, to O(a^2), the matrix elements of the\nfermion operators.\n  Our results are applicable also to the case of twisted mass fermions.\n  A longer write-up of this work, including non-perturbative results, is in\npreparation together with V. Gimenez, V. Lubicz and D. Palao.",
        "positive": "EspressoDB: A scientific database for managing high-performance\n  computing workflow: Leadership computing facilities around the world support cutting-edge\nscientific research across a broad spectrum of disciplines including\nunderstanding climate change, combating opioid addiction, or simulating the\ndecay of a neutron. While the increase in computational power has allowed\nscientists to better evaluate the underlying model, the size of these\ncomputational projects have grown to a point where a framework is desired to\nfacilitate managing the workflow. A typical scientific computing workflow\nincludes: Defining all input parameters for every step of the computation;\nDefining dependencies of computational tasks; Storing some of the output data;\nPost-processing these data files; Performing data analysis on output.\nEspressoDB is a programmatic object-relational data management framework\nimplemented in Python and based on the Django web framework. EspressoDB was\ndeveloped to streamline data management workflows, centralize and guarantee\ndata integrity, while providing domain flexibility and ease of use. The\nframework provided by EspressoDB aims to support the ever increasing complexity\nof workflows of scientific computing at leadership computing facilities, with\nthe goal of reducing the amount of human time required to manage the jobs, thus\ngiving scientists more time to focus on science."
    },
    {
        "anchor": "On chiral extrapolations of charmed meson masses and coupled-channel\n  reaction dynamics: We perform an analysis of QCD lattice data on charmed meson masses. The\nquark-mass dependence of the data set is used to gain information on the size\nof counter terms of the chiral Lagrangian formulated with open-charm states\nwith J^P= 0^- and J^P =1^- quantum numbers. Of particular interest are those\ncounter terms that are active in the exotic flavour sextet channel. A chiral\nexpansion scheme where physical masses enter the extrapolation formulae is\ndeveloped and applied to the lattice data set. Good convergence properties are\ndemonstrated and an accurate reproduction of the lattice data based on\nensembles of PACS-CS, MILC, ETMC and HSC with pion and kaon masses smaller than\n600 MeV is achieved. It is argued that a unique set of low-energy parameters is\nobtainable only if additional information from HSC on some scattering\nobservables is included in our global fits. The elastic and inelastic s-wave pi\nD and eta D scattering as considered by HSC is reproduced faithfully. Based on\nsuch low-energy parameters we predict 15 phase shifts and in-elasticities at\nphysical quark masses but also for an additional HSC ensemble at smaller pion\nmass. In addition we find a clear signal for a member of the exotic flavour\nsextet states in the eta D channel, below the bar K D_s threshold. For the\nisospin violating strong decay width of the D_{s0}(2317) we obtain the range\n(104-116) keV.",
        "positive": "Novel Approach to Super Yang-Mills Theory on Lattice - Exact fermionic\n  symmetry and \"Ichimatsu\" pattern -: We present a lattice theory with an exact fermionic symmetry, which mixes the\nlink and the fermionic variables. The staggered fermionic variables may be\nreconstructed into a Majorana fermion in the continuum limit. The gauge action\nhas a novel structure. Though it is the ordinary plaquette action, two\ndifferent couplings are assigned in the ``Ichimatsu pattern'' or the checkered\npattern. In the naive continuum limit, the fermionic symmetry survives as a\ncontinuum (or an $O(a^0)$) symmetry. The transformation of the fermion is\nproportional to the field strength multiplied by the difference of the two\ngauge couplings in this limit. This work is an extension of our recently\nproposed cell model toward the realization of supersymmetric Yang-Mills theory\non lattice."
    },
    {
        "anchor": "Nucleon sigma terms for 2+1 quark flavours: QCD lattice simulations yield hadron masses as functions of the quark masses.\nFrom the gradients of the hadron masses the sigma terms can then be determined.\nWe consider here dynamical 2+1 flavour simulations, in which we start from a\npoint of the flavour symmetric line and then keep the singlet or average quark\nmass fixed as we approach the physical point. This leads to highly constrained\nfits for hadron masses in a multiplet. The gradient of this path for a hadron\nmass then gives a relation between the light and strange sigma terms. A further\nrelation can be found from the change in the singlet quark mass along the\nflavour symmetric line. This enables light and strange sigma terms to be\nestimated for the baryon octet.",
        "positive": "The Sign Problem, PT Symmetry and Abelian Lattice Duality: Lattice field theories with complex actions are not easily studied using\nconventional analytic or simulation methods. However, a large class of these\nmodels are invariant under CT, where C is charge conjugation and T is time\nreversal, including models with non-zero chemical potential. For Abelian models\nin this class, lattice duality maps models with complex actions into dual\nmodels with real actions. For extended regions of parameter space, calculable\nfor each model, duality resolves the sign problem for both analytic methods and\ncomputer simulations. Explicit duality relations are given for models for spin\nand gauge models based on Z(N) and U(1) symmetry groups. The dual forms are\ngeneralizations of the Z(N) chiral clock model and the lattice\nFrenkel-Kontorova model, respectively. From these equivalences, rich sets of\nspatially-modulated phases are found in the strong-coupling region of the\noriginal models."
    },
    {
        "anchor": "Nonperturbative determination of $\u03b2$ functions for SU(3) gauge\n  theories with 10 and 12 fundamental flavors using domain wall fermions: Nonperturbative lattice field theory simulations provide a systematic\nframework to investigate properties of conformal systems at strong couplings.\nThese simulations can be performed using different lattice discretizations.\nHere we present numerical results for the step scaling beta function in SU(3)\ngauge theories with ten and twelve fundamental flavors. We calculate the\nrenormalized $\\beta$ function in the finite volume gradient flow\nrenormalization scheme. Using M\\\"obius domain wall fermions with Symanzik gauge\naction, Zeuthen gradient flow, and perturbative tree-level improvement, we\nimplement a fully $O(a^2)$ Symanzik improved set-up and demonstrate its\nadvantages. We compare our findings to existing results in the literature. For\nthe ten flavor system we observe excellent agreement with the domain wall\nstep-scaling function calculated by Chiu for the range in $g_c^2$ where our\ndata overlap. In the case of the twelve flavor system, our $O(a^2)$ Symanzik\nimproved set-up predicts a conformal infrared fixed point around $g_c^2 \\sim\n5.5$ in the $c=0.25$ scheme, which is presently in tension with staggered\nfermion results in the literature. We consider possible reasons for the\ndiscrepancy.",
        "positive": "Nf=2 Lattice QCD and Chiral Perturbation Theory: By employing a twisted mass term, we compare recent results from lattice\ncalculations of Nf=2 dynamical Wilson fermions with Wilson Chiral Perturbation\nTheory (WChPT). The final goal is to determine some combinations of\nGasser-Leutwyler Low Energy Constants (LECs). A wide set of data with different\nlattice spacings (a ~ 0.2-0.12 fm), different gauge actions (Wilson plaquette,\nDBW2) and different quark masses (down to the lowest pion mass allowed by\nlattice artifacts and including negative quark masses) provide a strong check\nof the applicability of WChPT in this regime and the scaling behaviours in the\ncontinuum limit."
    },
    {
        "anchor": "Density-of-states: Although Monte Carlo calculations using Importance Sampling have matured into\nthe most widely employed method for determining first principle results in QCD,\nthey spectacularly fail for theories with a sign problem or for which certain\nrare configurations play an important role. Non-Markovian Random walks, based\nupon iterative refinements of the density-of-states, overcome such overlap\nproblems. I will review the Linear Logarithmic Relaxation (LLR) method and, in\nparticular, focus onto ergodicity and exponential error suppression.\nApplications include the high-state Potts model, SU(2) and SU(3) Yang-Mills\ntheories as well as a quantum field theory with a strong sign problem: QCD at\nfinite densities of heavy quarks.",
        "positive": "On the Ambiguity of Spontaneously Broken Gauge Symmetry: Local gauge symmetries cannot break spontaneously, according to Elitzur's\ntheorem, but this leaves open the possibility of breaking some global subgroup\nof the local gauge symmetry, which is typically the gauge symmetry remaining\nafter certain (e.g. Coulomb or Landau) gauge choices. We show that in an SU(2)\ngauge-Higgs system such symmetries do indeed break spontaneously, but the\nlocation of the breaking in the phase diagram depends on the choice of global\nsubgroup. The implication is that there is no unique broken gauge symmetry, but\nrather many symmetries which break in different places. The problem is to\ndecide which, if any, of these gauge symmetry breakings is associated with a\ntransition between physically different, confining and non-confining phases.\nSeveral proposals - Kugo-Ojima, Coulomb, and monopole condensate - are\ndiscussed."
    },
    {
        "anchor": "Viscosity of pure-glue QCD from the lattice: We calculate shear viscosity and bulk viscosity in SU(3) gauge theory on the\nlattice at $1.5 \\,T_c$. The viscosities are extracted via a Kubo formula from\nthe reconstructed spectral function which we determine from the Euclidean-time\ndependence of the corresponding channel of the energy-momentum tensor\ncorrelators. We obtain unprecedented precision for the correlators by applying\ngradient flow and blocking methods. The correlators are extrapolated to the\ncontinuum and then to zero flow time. To extract the viscosities we fit\ntheoretically inspired models to the lattice data and crosscheck the fit\nresults using the Backus Gilbert method. The final estimates for shear and bulk\nviscosity are $\\eta/s = 0.15-0.48$ and $\\zeta/s = 0.017-0.059$.",
        "positive": "Three-dimensional physics and the pressure of hot QCD: We update Monte Carlo simulations of the three-dimensional SU(3) + adjoint\nHiggs theory, by extrapolating carefully to the infinite volume and continuum\nlimits, in order to estimate the contribution of the infrared modes to the\npressure of hot QCD. The sum of infrared contributions beyond the known 4-loop\norder turns out to be a smooth function, of a reasonable magnitude and specific\nsign. Unfortunately, adding this function to the known 4-loop terms does not\nimprove the match to four-dimensional lattice data, in spite of the fact that\nother quantities, such as correlation lengths, spatial string tension, or quark\nnumber susceptibilities, work well within the same setup. We outline possible\nways to reduce the mismatch."
    },
    {
        "anchor": "Effective Yukawa Couplings in Noncompact Lattice QED: We investigate effective Yukawa couplings of mesons to the elementary\nfermions in noncompact lattice QED. The couplings are extracted from suitable\nfermion-antifermion-meson three-point functions calculated by Monte Carlo\nsimulations with dynamical staggered fermions. The scaling behaviour is\ncompatible with expectations from perturbation theory, thus indicating\ntriviality of QED. The lines of constant Yukawa coupling are compared to flows\nof other quantities. Consistency is seen, at most, for weak coupling.",
        "positive": "A Variational Study of the Nucleon Wavefunction: The structure of the nucleon is studied variationally on the lattice by\nmaximizing the overlap between the nucleon and a trial function generated by an\ninterpolating field containing variational parameters. We examine the effect of\nthe spatial extent of smeared quark sources, the degree of gauge field\nsmearing, the positions of smeared quark sources, inclusion of lower Dirac\ncomponents and of diquark substructure. Exploratory calculations with quenched\nWilson fermions at a pion mass of 900 MeV achieved overlaps as high as 80%, and\nthere was no evidence of diquark substructure."
    },
    {
        "anchor": "Proof of the renormalizability of the gradient flow: We give an alternative perturbative proof of the renormalizability of the\nsystem defined by the gradient flow and the fermion flow in vector-like gauge\ntheories.",
        "positive": "Charmonium at finite temperature in quenched lattice QCD: We study charmonium correlators in pseudoscalar and vector channels at finite\ntemperature using lattice QCD simulation in the quenched approximation.\nAnisotropic lattices are used in order to have sufficient numbers of degrees of\nfreedom in the Euclidean temporal direction. We focus on the low energy\nstructure of the spectral function, corresponding to the ground state in the\nhadron phase, by applying the smearing technique to enhance the contribution to\nthe correlator from this region. We employ two analysis procedures: the maximum\nentropy method (MEM) for the extraction of the spectral function without\nassuming a specific form, to estimate the shape of the spectral function, and\nthe standard $\\chi^2$ fit analysis using typical forms in accordance with the\nresult of MEM, for a more quantitative evaluation. To verify the applicability\nof the procedures, we first analyze the smeared correlators as well as the\npoint correlators at zero temperature. We find that by shortening the\n$t$-interval used for the analysis (a situation inevitable at $T>0$) the\nreliability of MEM for point correlators is lost, while it subsists for smeared\ncorrelators. Then the smeared correlators at $T\\simeq 0.9 T_c$ and $1.1 T_c$\nare analyzed. At $T\\simeq 0.9 T_c$, the spectral function exhibits a strong\npeak, well approximated by a delta function corresponding to the ground state\nwith almost the same mass as at T=0. At $T\\simeq 1.1 T_c$, we find that the\nstrong peak structure still persists at almost the same place as below $T_c$,\nbut with a finite width of a few hundred MeV. This result indicates that the\ncorrelators possess a nontrivial structure even in the deconfined phase."
    },
    {
        "anchor": "Calculation of $\u03c1$ meson decay width from the PACS-CS configurations: We present preliminary results on the $\\rho$ meson decay width from $N_f=2+1$\nfull QCD configurations generated by PACS-CS Collaboration. The decay width is\nestimated from the $P$-wave scattering phase shift for the isospin $I=1$\ntwo-pion system. The finite size formula presented by L\\\"uscher in the center\nof mass frame and its extension to non-zero total momentum frame by Rummukainen\nand Gottlieb are employed for the calculations of the phase shift. Our\ncalculations are carried out at $m_\\pi=410\\ {\\rm MeV}$ ($m_\\pi/m_\\rho=0.46$)\nand $a=0.091\\ {\\rm fm}$ on a $32^3\\times 64$ ($La=2.9 {\\rm fm}$) lattice.",
        "positive": "Moment of inertia and supervortical temperature of gluon plasma: Using lattice simulations, we analyze the influence of uniform rotation on\nthe equation of state of gluodynamics. For a sufficiently slow rotation, the\nfree energy of the system can be expanded into a series of powers of angular\nvelocity. We calculate the moment of inertia given by the quadratic coefficient\nof this expansion using both analytic continuation and derivative methods,\nwhich demonstrate a good agreement between the results. We find that the moment\nof inertia unexpectedly takes a negative value below the ``supervortical\ntemperature'' $T_s = 1.50(10) T_c$, vanishes at $T = T_s$, and becomes a\npositive quantity at higher temperatures. We discuss how our results are\nrelated to the scale anomaly and the magnetic gluon condensate. We point out\nthat the negativity of the moment of inertia is in qualitative agreement with\nour previous lattice calculations, indicating that the rigid rotation increases\nthe critical temperatures in gluodynamics and QCD."
    },
    {
        "anchor": "Index Theorem and Overlap Formalism with Naive and Minimally Doubled\n  Fermions: We present a theoretical foundation for the Index theorem in naive and\nminimally doubled lattice fermions by studying the spectral flow of a Hermitean\nversion of Dirac operators. We utilize the point splitting method to implement\nflavored mass terms, which play an important role in constructing proper\nHermitean operators. We show the spectral flow correctly detects the index of\nthe would-be zero modes which is determined by gauge field topology. Using the\nflavored mass terms, we present new types of overlap fermions from the naive\nfermion kernels, with a number of flavors that depends on the choice of the\nmass terms. We succeed to obtain a single-flavor naive overlap fermion which\nmaintains hypercubic symmetry.",
        "positive": "On the Phase Diagram of Massive Yang-Mills: The phases of a lattice gauge model for the massive Yang-Mills are\ninvestigated. The phase diagram supports the recent conjecture on the large\nenergy behavior of nonlinearly realized massive gauge theories (i.e. mass a` la\nStueckelberg, no Higgs mechanism), envisaging a Phase Transition (PT) to an\nasymptotically free massless Yang-Mills theory."
    },
    {
        "anchor": "Nucleon to $\u0394$ and $\u0394$ form factors in Lattice QCD: We present recent lattice QCD results on the electroweak nucleon to $\\Delta$\ntransition and $\\Delta$ form factors using dynamical fermion gauge\nconfigurations with a lowest pion mass of about 300 MeV, with special emphasis\nin the determination of the sub-dominant quadrupole $N\\gamma^*\\rightarrow\n\\Delta$ and $\\Delta$ electromagnetic form factors.",
        "positive": "Status of Heavy Quark Physics on the Lattice: The status of lattice calculations of some phenomenology of heavy quarks is\npresented. Emphasis is on progress made in calculating those quantities\nrelevant to estimating parameters of the quark mixing matrix, namely leptonic\ndecay constants, the bag parameter of neutral $B$ mixing, and semileptonic form\nfactors. New results from studies of quarkonia are highlighted."
    },
    {
        "anchor": "Higher order tensor renormalization group for relativistic fermion\n  systems: We apply the higher order tensor renormalization group to two and three\ndimensional relativistic fermion systems on the lattice. In order to perform a\ncoarse-graining of tensor networks including Grassmann variables, we introduce\nGrassmann higher order tensor renormalization group. We test the validity of\nthe new algorithm by comparing its results with those of exact or previous\nmethods.",
        "positive": "Low-lying odd-parity nucleon resonances as quark-model like states: Recent lattice QCD results for the low-lying odd-parity excitations of the\nnucleon near the $N^{*}(1535)$ and $N^{*}(1650)$ resonance positions have\nrevealed that the lattice QCD states have magnetic moments consistent with\npredictions from a constituent-quark-model. Using Hamiltonian Effective Field\nTheory (HEFT) to describe pion-nucleon scattering in the $I(J^{P}) =\n\\frac{1}{2}(\\frac{1}{2}^{-})$ channel, we represent these two quark-model like\nstates as two single-particle bare basis states, dressed and mixed by\nmeson-baryon scattering channels. By constraining the free parameters of the\nHamiltonian with $S_{11}$ pion-nucleon scattering data, we perform the first\ncalculation of the finite-volume spectrum using two bare-baryon basis states.\nBy comparing this spectrum to contemporary lattice QCD results at three lattice\nvolumes, we analyse the eigenvectors of the Hamiltonian to gain insight into\nthe structure and composition of these two low-lying resonances. We find that\nan interpretation of the two low-lying nucleon resonances as quark-model like\nstates dressed by meson-baryon interactions is consistent with both the\n$S_{11}$ scattering data and lattice QCD. We introduce a novel HEFT formalism\nfor estimating scattering-state contaminations in lattice QCD correlation\nfunctions constructed with standard three-quark operators. Not only are\nhistorical lattice QCD results described with excellent accuracy, but\ncorrelation functions with large scattering-state contaminations are\nidentified."
    },
    {
        "anchor": "High temperature meson propagators with domain-wall quarks: We study the chiral properties of domain-wall quarks at high temperatures on\nan ensemble of quenched configurations. Low lying eigenmodes of the Dirac\noperator are calculated and used to check the extent to which the Atiyah-Singer\nindex theorem is obeyed on lattices with finite $N_5$. We calculate the\nconnected and disconnected screening propagators for the lowest mass scalar and\npseudoscalar mesons in the sectors of different topological charge and note\nthat they behave as expected. Separating out the would-be zero eigenmodes\nenables us to accurately estimate the disconnected propagators with far less\neffort than would be needed otherwise.",
        "positive": "High density QCD on a Lefschetz thimble?: It is sometimes speculated that the sign problem that afflicts many quantum\nfield theories might be reduced or even eliminated by choosing an alternative\ndomain of integration within a complexified extension of the path integral (in\nthe spirit of the stationary phase integration method). In this paper we start\nto explore this possibility somewhat systematically. A first inspection reveals\nthe presence of many difficulties but - quite surprisingly - most of them have\nan interesting solution. In particular, it is possible to regularize the\nlattice theory on a Lefschetz thimble, where the imaginary part of the action\nis constant and disappears from all observables. This regularization can be\njustified in terms of symmetries and perturbation theory. Moreover, it is\npossible to design a Monte Carlo algorithm that samples the configurations in\nthe thimble. This is done by simulating, effectively, a five dimensional\nsystem. We describe the algorithm in detail and analyze its expected cost and\nstability. Unfortunately, the measure term also produces a phase which is not\nconstant and it is currently very expensive to compute. This residual sign\nproblem is expected to be much milder, as the dominant part of the integral is\nnot affected, but we have still no convincing evidence of this. However, the\nmain goal of this paper is to introduce a new approach to the sign problem,\nthat seems to offer much room for improvements. An appealing feature of this\napproach is its generality. It is illustrated first in the simple case of a\nscalar field theory with chemical potential, and then extended to the more\nchallenging case of QCD at finite baryonic density."
    },
    {
        "anchor": "Finite-size scaling and deconfinement transition in gauge theories: A new method is proposed for determining the critical indices of the\ndeconfinement transition in gauge theories, based on the finite-size scaling\nanalysis of simple lattice operators, such as the plaquette. A precise\ndetermination of the critical index $\\nu$, in agreement with the prediction of\nthe Svetitsky-Yaffe conjecture, is obtained for SU(3) gauge theory in\n(2+1)-dimension. Preliminary results for SU(2) in (3+1)-dimension are also\ngiven.",
        "positive": "Spontaneous breaking of residual gauge symmetries on the lattice: Lattice gauge theories are considered with a partial axial gauge fixing along\none direction only. This leaves a residual gauge symmetry that is still local\nin three directions but now global in one. It is found that this $N^{d-1}$ fold\nsymmetry (on an $N^d$ lattice) breaks spontaneously at weak coupling with the\ngauge field elements on links averaged over 1-d chains along the gauge-fixing\ndirection as order parameters. This phase transition is observed with\nMonte-Carlo simulations for both 3-d Z2 and 4-d SU(2) pure gauge theories and\nappears to be coincident with the deconfinement transition. This work calls\ninto question the equivalence of different gauges in certain circumstances."
    },
    {
        "anchor": "Topological susceptibility at $T>T_{\\rm c}$ from master-field\n  simulations of the SU(3) gauge theory: The topological susceptibility is computed in the SU(3) gauge theory at\ntemperatures $T$ above the critical temperature $T_{\\rm c}$ using master-field\nsimulations of very large lattices, where the infamous topology-freezing issue\nis effectively bypassed. Up to $T=2.0\\,T_{\\rm c}$ no unusually large lattice\neffects are observed and the results obtained in the continuum limit confirm\nthe expected rapid decay of the susceptibility with increasing temperature. As\na byproduct, the reference gradient-flow time $t_0$ is determined in the range\nof lattice spacings from $0.023$ to $0.1\\,{\\rm fm}$ with a precision of 2 per\nmille.",
        "positive": "The CKM matrix and flavor physics from lattice QCD: I discuss the role of lattice QCD in testing the Standard Model and searching\nfor physics beyond the Standard Model in the quark flavor sector. I first\nreview the Standard Model CKM framework. I then present the current status of\nthe CKM matrix, focusing on determinations of CKM matrix elements and\nconstraints on the CKM unitarity triangle that rely on lattice QCD calculations\nof weak matrix elements. I also show the potential impact of improved lattice\nQCD calculations on the global CKM unitarity triangle fit. I then describe\nseveral hints of new physics in the quark flavor sector that rely on lattice\nQCD calculations of weak matrix elements, such as evidence of a ~2-3 sigma\ntension in the CKM unitarity triangle and the \"f_{D_s} puzzle\". I finish with a\ndiscussion of lattice QCD calculations of rare B- and K-decays needed to probe\nphysics beyond the Standard Model at future experiments."
    },
    {
        "anchor": "Gluon Mass in Landau Gauge QCD: The interpretation of the Landau gauge lattice gluon propagator as a massive\ntype bosonic propagator is investigated for i) an infrared constant gluon mass;\nii) an ultraviolet constant gluon mass; iii) a momentum dependent mass. We find\nthat the infrared data can be associated with a massive propagator with a\nconstant gluon mass of 651(12) MeV, but the ultraviolet lattice data is not\ncompatible this type of propagator. The scenario of a momentum dependent gluon\nmass gives a decreasing mass with the momentum, starting from a value of $\\sim\n630$ MeV in the infrared region and suggesting a $q^2 \\ln q^2$ dependence for\nmomenta above 1 GeV.",
        "positive": "Inside the SU(3) quark-antiquark QCD flux tube: screening versus quantum\n  widening: In lattice QCD, colour confinement manifests in flux tubes. We compute in\ndetail the quark-antiquark flux tube for pure gauge SU(3) dimension $D=3+1$ for\nquark-antiquark distances R ranging from 0.4 fm to 1.4 fm. To increase the\nsignal over noise ratio, we apply the improved multihit and extended smearing\ntechniques. We detail the gauge invariant squared components of the colour\nelectric and colour magnetic fields both in the mediator plane between the\nstatic quark and static antiquark and in the planes of the sources. We fit the\nfield densities with appropriate ansatze and we observe the screening of the\ncolour fields in all studied planes together with the quantum widening of the\nflux tube in the mediator plane. All components squared of the colour fields\nare non-vanishing and are consistent with a penetration length lambda ~ 0.22 to\n0.24 fm and an effective screening mass mu ~ 0.9 to 0.8 GeV. The quantum\nwidening of the flux tube is well fitted with a logarithmic law in R."
    },
    {
        "anchor": "The Nf=0 heavy quark potential from short to intermediate distances: We study the potential of a static quark anti-quark pair in the range 0.05fm\n\\leq r \\leq 0.8fm, employing a sequence of lattices up to 64^4. Lattice\nartifacts in potential and force are investigated theoretically as well as\nnumerically and continuum quantities are obtained by extrapolation of the\nresults at finite lattice spacing. Consistency of the numerical results with\nthe form of scaling violations predicted by an analysis `a la Symanzik is\nfound. The scale r_0/a is determined for the Wilson action up to beta=6.92.",
        "positive": "Group-theoretical construction of finite-momentum and multi-particle\n  operators for lattice hadron spectroscopy: Determining the spectrum of hadronic excitations from Monte Carlo simulations\nrequires the use of interpolating operators that couple to multi-particle\nstates. Recent algorithmic advances have made the inclusion of multi-hadron\noperators in spectroscopy calculations a practical reality. In this talk, a\nprocedure for constructing a set of multi-hadron interpolators that project\nonto the states of interest is described. To aid in the interpretation of\nsimulation data, operators are designed to transform irreducibly under the\nlattice symmetry group. The identification of a set of optimal single-hadron\ninterpolators for states with non-zero momenta is an essential intermediate\nstep in this analysis."
    },
    {
        "anchor": "Nucleon strange electromagnetic form factors: The role of the strange quarks on the low-energy interactions of the proton\ncan be probed through the strange electromagnetic form factors. Knowledge of\nthese form factors provides essential input for parity-violating processes and\ncontributes to the understanding of the sea quark dynamics. We determine the\nstrange electromagnetic form factors of the nucleon within the lattice\nformulation of Quantum Chromodynamics using simulations that include light,\nstrange and charm quarks in the sea all tuned to their physical mass values. We\nemploy state-of-the-art techniques to accurately extract the form factors for\nvalues of the momentum transfer square up to 0.8~GeV$^2$. We find that both the\nelectric and magnetic form factors are statistically non-zero. We obtain for\nthe strange magnetic moment $\\mu^s=-0.017(4)$, the strange magnetic radius\n$\\langle r^2_M \\rangle^s=-0.015(9)$~fm$^2$, and the strange charge radius\n$\\langle r^2_E \\rangle^s=-0.0048(6)$~fm$^2$.",
        "positive": "Evidence for fractional topological charge in SU(2) pure Yang-Mills\n  theory: We investigate the spectral flows of the hermitian Wilson-Dirac operator in\nthe fundamental and adjoint representations on two ensembles of pure SU(2)\ngauge field configurations at the same physical volume. We find several\nbackground gauge field configurations where the index of the hermitian\nWilson-Dirac operator in the adjoint representation is not four times the index\nin the fundamental representation. This could imply a topological basis for the\nexistence of degenerate vacua in supersymmetric Yang-Mills theories."
    },
    {
        "anchor": "SO(3) vortices and disorder in the 2d SU(2) chiral model: We study the correlation function of the 2d SU(2) principal chiral model on\nthe lattice. By rewriting the model in terms of Z(2) degrees of freedom coupled\nto SO(3) vortices we show that the vortices play a crucial role in disordering\nthe correlations at low temperature. Using a series of exact transformations we\nprove that, if satisfied, certain inequalities between vortex correlations\nimply exponential fall-off of the correlation function at arbitrarily low\ntemperatures. We also present some Monte Carlo evidence that these correlation\ninequalities are indeed satisfied. Our method can be easily translated to the\nlanguage of 4d SU(2) gauge theory to establish the role of corresponding SO(3)\nmonopoles in maintaining confinement at small couplings.",
        "positive": "Perturbative predictions for color superconductivity on the lattice: We develop a new method to investigate color superconductivity (CSC) on the\nlattice based on the Thouless criterion, which amounts to solving the\nlinearized gap equation without imposing any ansatz on the structure of the\nCooper pairs. We perform explicit calculations at the one-loop level with the\nstaggered fermions on a $8^3 \\times 128$ lattice and the Wilson fermions on a\n$4^3 \\times 128$ lattice, which enables us to obtain the critical\n$\\beta(=6/g^2)$ as a function of the quark chemical potential $\\mu$, below\nwhich the CSC phase is expected to appear. The obtained critical $\\beta$ has\nsharp peaks at the values of $\\mu$ corresponding to the discretized energy\nlevels of quarks similarly to what was observed in previous studies on\nsimplified effective models. From the solution to the linearized gap equation,\none can read off the flavor and spatial structures of the Cooper pairs at the\ncritical $\\beta$. In the case of massless staggered fermion, in particular, we\nfind that the chiral $\\mathrm{U}(1)$ symmetry of the staggered fermions is\nspontaneously broken by the condensation of the Cooper pairs."
    },
    {
        "anchor": "On the renormalized scalar density in quenched QCD: We present a non-perturbative determination of the renormalization factor Z_S\nof the scalar density in quenched QCD with overlap fermions. Results are\nobtained at four values of the lattice spacing. By combining Z_S with results\nfor the low-energy constant Sigma we are able to compute the renormalization\ngroup invariant scalar condensate in the continuum limit with a total accuracy\nof 7%, excluding dynamical quark effects. Our result translates to\nSigma_msbar(2 GeV)=(285+/-9 MeV)^3 if the scale is set by the kaon decay\nconstant. We have also performed scaling studies of the pseudoscalar decay\nconstant and the vector mass. Our results indicate that quantities computed\nusing overlap quarks exhibit excellent scaling behaviour, with small residual\nlattice artifacts.",
        "positive": "Gauge Invariance and Lattice Monopoles: The number and the location of monopoles in Lattice configurations depend on\nthe choice of the gauge, in contrast to the obvious requirement that monopoles,\nas physical objects, have a gauge-invariant status.\n  It is proved, starting from non-abelian Bianchi identities, that monopoles\nare indeed gauge-invariant: the technique used to detect them has instead an\nefficiency which depends on the choice of the abelian projection, in a known\nand well understood way."
    },
    {
        "anchor": "Heavy quark potential in the instanton liquid model: We study the heavy quark potential in the instanton liquid model by carefully\nmeasuring Wilson loops out to a distance of order 3$fm$. A random instanton\nensemble with a fixed radius $\\rho$ = 1/3$fm$ generates a potential $V(R)$\ngrowing very slowly at large $R$. In contrast, a more realistic size\ndistribution growing as $\\rho^6$ at small $\\rho$ and decaying as $\\rho^{-5}$ at\nlarge $\\rho$, leads to a potential which grows linearly with $R$. The string\ntension, however, is only about 1/10 of the phenomenological value.",
        "positive": "Chiral effective field theory beyond the power-counting regime: Novel techniques are presented, which identify the chiral power-counting\nregime (PCR), and realize the existence of an intrinsic energy scale embedded\nin lattice QCD results that extend outside the PCR. The nucleon mass is\nconsidered as a benchmark for illustrating this new approach. Using\nfinite-range regularization, an optimal regularization scale can be extracted\nfrom lattice simulation results by analyzing the renormalization of the low\nenergy coefficients. The optimal scale allows a description of lattice\nsimulation results that extend beyond the PCR by quantifying and thus handling\nany scheme-dependence. Preliminary results for the nucleon magnetic moment are\nalso examined, and a consistent optimal regularization scale is obtained. This\nindicates the existence of an intrinsic scale corresponding to the finite size\nof the source of the pion cloud."
    },
    {
        "anchor": "Lattice Computations of the Pion Form Factor: We report on a program to compute the electromagnetic form factors of mesons.\nWe discuss the techniques used to compute the pion form factor and present\nresults computed with domain wall valence fermions on MILC asqtad lattices, as\nwell as with Wilson fermions on quenched lattices. The methods can easily be\nextended to rho-to-gamma-pi transition form factors.",
        "positive": "Towards the physical point hadronic vacuum polarisation from Moebius DWF: We present steps towards the computation of the leading-order hadronic\ncontribution to the muon anomalous magnetic moment on RBC/UKQCD physical point\nDWF ensembles. We discuss several methods for controlling and reducing\nuncertainties associated to the determination of the HVP form factor."
    },
    {
        "anchor": "Dual Wilson Loop and Infrared Monopole Condensation in Lattice QCD in\n  the Maximally Abelian Gauge: Using the SU(2) lattice QCD, we formulate the dual Wilson loop and study the\ndual Higgs mechanism induced by monopole condensation in the maximally abelian\n(MA) gauge, where QCD is reduced into an abelian gauge theory including the\nelectric current $j_\\mu$ and the monopole current $k_\\mu$. After the abelian\nprojection in the MA gauge, the system can be separated into the photon part\nand the monopole part corresponding to the separation of $j_\\mu$ and $k_\\mu$,\nrespectively. We study here the monopole part (the monopole-current system),\nwhich is responsible to the electric confinement. Owing to the absence of\nelectric currents, the monopole part is naturally described using the dual\ngluon field $B_\\mu$ without the Dirac-string singularity. Defining the dual\nWilson loop from the dual gluon $B_\\mu$, we find the perimeter law of the dual\nWilson loop in the lattice QCD simulation. In the monopole part in the MA\ngauge, the inter-monopole potential is found to be flat, and can be fitted as\nthe Yukawa potential in the infrared region after the subtraction of the\nartificial finite-size effect on the dual Wilson loop. From more detailed\nanalysis of the inter-monopole potential considering the monopole size, we\nestimate the effective dual-gluon mass $m_B \\simeq 0.5$GeV and the effective\nmonopole size $R \\simeq 0.2$fm. The effective mass of the dual gluon field at\nthe long distance can be regarded as an evidence of ``infrared monopole\ncondensation''.",
        "positive": "$F_K / F_\u03c0$ from M\u00f6bius domain-wall fermions solved on\n  gradient-flowed HISQ ensembles: We report the results of a lattice quantum chromodynamics calculation of\n$F_K/F_\\pi$ using M\\\"{o}bius domain-wall fermions computed on gradient-flowed\n$N_f=2+1+1$ highly-improved staggered quark (HISQ) ensembles. The calculation\nis performed with five values of the pion mass ranging from $130 \\lesssim m_\\pi\n\\lesssim 400$ MeV, four lattice spacings of $a\\sim 0.15, 0.12, 0.09$ and $0.06$\nfm and multiple values of the lattice volume. The interpolation/extrapolation\nto the physical pion and kaon mass point, the continuum, and infinite volume\nlimits are performed with a variety of different extrapolation functions\nutilizing both the relevant mixed-action effective field theory expressions as\nwell as discretization-enhanced continuum chiral perturbation theory formulas.\nWe find that the $a\\sim0.06$ fm ensemble is helpful, but not necessary to\nachieve a subpercent determination of $F_K/F_\\pi$. We also include an estimate\nof the strong isospin breaking corrections and arrive at a final result of\n$F_{K^\\pm}/F_{\\pi^\\pm} = 1.1942(45)$ with all sources of statistical and\nsystematic uncertainty included. This is consistent with the Flavour Lattice\nAveraging Group average value, providing an important benchmark for our lattice\naction. Combining our result with experimental measurements of the pion and\nkaon leptonic decays leads to a determination of $|V_{us}|/|V_{ud}| =\n0.2311(10)$."
    },
    {
        "anchor": "Structure of hybrid static potential flux tubes in lattice Yang-Mills\n  theory: We report about an ongoing lattice field theory project concerned with the\ninvestigation of heavy hybrid mesons. In particular we discuss our computation\nof the structure of hybrid static potential flux tubes in SU(2) lattice\nYang-Mills theory, which is based on the squares of the chromoelectric and\nchromomagnetic field strength components. Our flux tube results for hybrid\nstatic potential quantum numbers $\\Sigma_g^-$, $\\Sigma_u^+$, $\\Sigma_u^-$,\n$\\Pi_g$, $\\Pi_u$, $\\Delta_g$, $\\Delta_u$ are significantly different compared\nto the flux tube of the ordinary static potential.",
        "positive": "A new way to deal with fermions in Monte Carlo simulations: An exact, nonlocal, finite step-size algorithm for Monte Carlo simulation of\ntheories with dynamical fermions is proposed. The algorithm is based on\nobtaining the new configuration U' from the old one U by solving the equation $\nM(U') \\eta = \\omega M(U) \\eta$, where $M$ is fermionic operator, $\\eta$ is\nrandom Gaussian vector, and $\\omega$ is random real number close to unity. This\nalgorithm can be used for the acceleration of current simulations in theories\nwith Grassmann variables. A first test was done for SU(3) QCD with purely\nfermionic term in the action."
    },
    {
        "anchor": "A proposal of a fine tuning free formulation of 4d N=4 super Yang-Mills: Recently, a nonperturbative formulation of 4d N=4 super Yang-Mills theory\nwhich does not require fine tuning at least to all order in perturbation theory\nhas been proposed by combining two-dimensional lattice and matrix model\ntechniques. In this paper we provide an analogous model by utilizing\ndeconstruction approach of Kaplan et al. Two-dimensional lattice with a plane\nwave deformation is deconstructed from a matrix model and two additional\ndimensions emerge through the Myers effect. In other words we construct a\nD1-brane theory from which a D3-brane theory comes out. The action is much\nsimpler than the previous formulation and hence numerical study, which enables\nus to test the AdS/CFT duality at fully nonperturbative level, becomes much\neasier.",
        "positive": "Phase diagram of QCD in a magnetic background: We provide numerical evidence that the thermal QCD crossover turns into a\nfirst order transition in the presence of large enough magnetic background\nfields. The critical endpoint is found to be located between $eB = 4$ GeV$^2$\n(where the pseudocritical temperature is $T_c = (98 \\pm 3)$ MeV) and $eB = 9$\nGeV$^2$ (where the critical temperature is $T_c = (63 \\pm 5)$ MeV). Results are\nbased on the analysis of quark condensates and number susceptibilities,\ndetermined by lattice simulations of $N_f = 2+1$ QCD at the physical point,\ndiscretized with three different lattice spacings, $a = 0.114, 0.086$ and\n$0.057$ fm, via rooted stout staggered fermions and a Symanzik tree level\nimproved pure gauge action. We also present preliminary results regarding the\nconfining properties of the thermal theory, suggesting that they could change\ndrastically going across the phase transition"
    },
    {
        "anchor": "$\u039b_b \\to p \\ell^- \\bar\u03bd_\\ell$ and $\u039b_b \\to \u039b_c\n  \\ell^- \\bar\u03bd_\\ell$ form factors from lattice QCD with relativistic heavy\n  quarks: Measurements of the $\\Lambda_b \\to p \\ell^- \\bar{\\nu}_\\ell$ and $\\Lambda_b\n\\to \\Lambda_c \\ell^- \\bar{\\nu}_\\ell$ decay rates can be used to determine the\nmagnitudes of the CKM matrix elements $V_{ub}$ and $V_{cb}$, provided that the\nrelevant hadronic form factors are known. Here we present a precise calculation\nof these form factors using lattice QCD with 2+1 flavors of dynamical\ndomain-wall fermions. The $b$ and $c$ quarks are implemented with relativistic\nheavy-quark actions, allowing us to work directly at the physical heavy-quark\nmasses. The lattice computation is performed for six different pion masses and\ntwo different lattice spacings, using gauge-field configurations generated by\nthe RBC and UKQCD collaborations. The $b \\to u$ and $b \\to c$ currents are\nrenormalized with a mostly nonperturbative method. We extrapolate the form\nfactor results to the physical pion mass and the continuum limit, parametrizing\nthe $q^2$-dependence using $z$-expansions. The form factors are presented in\nsuch a way as to enable the correlated propagation of both statistical and\nsystematic uncertainties into derived quantities such as differential decay\nrates and asymmetries. Using these form factors, we present predictions for the\n$\\Lambda_b \\to p \\ell^- \\bar{\\nu}_\\ell$ and $\\Lambda_b \\to \\Lambda_c \\ell^-\n\\bar{\\nu}_\\ell$ differential and integrated decay rates. Combined with\nexperimental data, our results enable determinations of $|V_{ub}|$, $|V_{cb}|$,\nand $|V_{ub}/V_{cb}|$ with theory uncertainties of 4.4%, 2.2%, and 4.9%,\nrespectively.",
        "positive": "The status of pentaquark spectroscopy on the lattice: The present work is a summary of the status of lattice pentaquark\ncalculations. After a pedagogic introduction to the basics of lattice hadron\nspectroscopy we give a critical comparison of results presently available in\nthe literature. Special emphasis is put on presenting some of the possible\npitfalls of these calculations. In particular we discuss at length the choice\nof the hadronic operators and the separation of genuine five-quark states from\nmeson-baryon scattering states."
    },
    {
        "anchor": "Isolating Excited States of the Nucleon in Lattice QCD: We discuss a robust projection method for the extraction of excited-state\nmasses of the nucleon from a matrix of correlation functions. To illustrate the\nalgorithm in practice, we present results for the positive parity excited\nstates of the nucleon in quenched QCD. Using eigenvectors obtained via the\nvariational method, we construct an eigenstate-projected correlation function\namenable to standard analysis techniques. The method displays its utility when\ncomparing results from the fit of the projected correlation function with those\nobtained from the eigenvalues of the variational method. Standard nucleon\ninterpolators are considered, with $2\\times 2$ and $3\\times 3$ correlation\nmatrix analyses presented using various combinations of source-smeared,\nsink-smeared and smeared-smeared correlation functions. Using these new robust\nmethods, we observe a systematic dependency of the nucleon excited-state masses\non source- and sink-smearing levels. To the best of our knowledge, this is the\nfirst clear indication that a correlation matrix of standard nucleon\ninterpolators is insufficient to isolate the eigenstates of QCD.",
        "positive": "B-physics from HQET in two-flavour lattice QCD: We present our analysis of B physics quantities using non-perturbatively\nmatched Heavy Quark Effective Theory (HQET) in Nf= 2 lattice QCD on the CLS\nensembles. Using all-to-all propagators, HYP-smeared static quarks, and the\nGeneralized Eigenvalue Problem (GEVP) approach with a conservative plateau\nselection procedure, we are able to systematically control all sources of\nerror. With significantly increased statistics compared to last year, our\npreliminary results are mb (mb) = 4.22(10)(4)z GeV for the MS b-quark mass, and\nfB = 193(9)stat (4)_\\chi MeV and fBs = 219(12)stat MeV for the B-meson decay\nconstants."
    },
    {
        "anchor": "Strong Non-Ultralocality of Ginsparg-Wilson Fermionic Actions: It is shown that it is impossible to construct a free theory of fermions on\ninfinite hypercubic Euclidean lattice in even number of dimensions that: (a) is\nultralocal, (b) respects the symmetries of hypercubic lattice, (c) chirally\nnonsymmetric part of its propagator is local, and (d) describes single species\nof massless Dirac fermions in the continuum limit. This establishes\nnon-ultralocality for arbitrary doubler-free Ginsparg-Wilson fermionic action\nwith hypercubic symmetries (\"strong non-ultralocality\"), and complements the\nearlier general result on non-ultralocality of infinitesimal\nGinsparg-Wilson-Luscher symmetry transformations (\"weak non-ultralocality\").",
        "positive": "Lattice String Field Theory: String field theory is a candidate for a full non-perturbative definition of\nstring theory. We aim to define string field theory on a space-time lattice to\ninvestigate its behaviour at the quantum level. Specifically, we look at string\nfield theory in a one dimensional linear dilaton background. We report the\nfirst results of our simulations."
    },
    {
        "anchor": "Gaussian states for the variational study of (1+1)-dimensional lattice\n  gauge models: We introduce a variational ansatz based on Gaussian states for\n(1+1)-dimensional lattice gauge models. To this end we identify a set of\nunitary transformations which decouple the gauge degrees of freedom from the\nmatter fields. Using our ansatz, we study static aspects as well as real-time\ndynamics of string breaking in two (1+1)-dimensional theories, namely QED and\ntwo-color QCD. We show that our ansatz captures the relevant features and is in\nexcellent agreement with data from numerical calculations with tensor networks.",
        "positive": "Gauge Invariant Monopoles in Lattice SU(2) Gluodynamics: We consider lattice implementation of the recently proposed gauge invariant\ndefinition of the monopole charge. Because of the lattice discretization the\nalgorithm gives rise to specific lattice artifacts and an effective Ising\nmodel. The Ising-model problem might in principle be solved and we discuss the\nrole of the Maximal Abelian gauge in this respect. The lattice artifacts are\nmuch more difficult to deal with since they are mixed up with monopoles thus\nobscuring the physical observables. Nevertheless, it is possible to extract the\ndensity of physical monopoles which seems to scale correctly towards the\ncontinuum limit."
    },
    {
        "anchor": "$N\u03c0$-states and the projection method for the nucleon axial and\n  pseudoscalar form factors: The RQCD collaboration proposed a projection method to remove the excited\nstate contamination in lattice OCD calculations of nuclear form factors. The\neffectiveness of this method in removing the two-particle nucleon-pion-state\ncontamination is examined using chiral perturbation theory. It is shown that\nthe projection method has practically no impact in the calculation of the axial\nand induced pseudoscalar form factors. In the pseudoscalar form factor the\nprojection method strongly enhances the nucleon-pion-state contamination. The\ngeneralized Goldberger-Treiman relation is satisfied even though large\nnucleon-pion-state contaminations are present in individual form factors.\nTherefore, the projection method is not a solution to the excited state problem\nin nucleon form factor calculations.",
        "positive": "The phase diagram of Yang-Mills theory with a compact extra dimension: We present a non-perturbative study of the phase diagram of SU(2) Yang-Mills\ntheory in a five-dimensional spacetime with a compact extra dimension. The\nnon-renormalizable theory is regularized on an anisotropic lattice and\ninvestigated through numerical simulations in a regime characterized by a\nhierarchy between the scale of low-energy physics, the inverse compactification\nradius, and the cutoff scale. We map out the structure of the phase diagram and\nthe pattern of lines corresponding to fixed values of the ratio between the\nmass of the fifth component of the gauge field and the non-perturbative mass\ngap of the four-dimensional modes. We discuss different limits of the model,\nand comment on the implications of our findings."
    },
    {
        "anchor": "Holography on the lattice: the string worldsheet perspective: We review the study, on the lattice, of the Green-Schwarz gauge-fixed string\naction describing worldsheet fluctuations about the minimal surface\nholographically dual to the null cusp Wilson loop, useful to evaluate the cusp\nanomaly of N = 4 super Yang-Mills (sYM). We comment on discretization,\nnumerical explorations and challenges for the non-perturbative study of this\nbenchmark model of gauge-fixed worldsheet actions.",
        "positive": "Exceptional Deconfinement in G(2) Gauge Theory: The Z(N) center symmetry plays an important role in the deconfinement phase\ntransition of SU(N) Yang-Mills theory at finite temperature. The exceptional\ngroup G(2) is the smallest simply connected gauge group with a trivial center.\nHence, there is no symmetry reason why the low- and high-temperature regimes in\nG(2) Yang-Mills theory should be separated by a phase transition. Still, we\npresent numerical evidence for the presence of a first order deconfinement\nphase transition at finite temperature. Via the Higgs mechanism, G(2) breaks to\nits SU(3) subgroup when a scalar field in the fundamental {7} representation\nacquires a vacuum expectation value v. Varying v we investigate how the G(2)\ndeconfinement transition is related to the one in SU(3) Yang-Mills theory.\nInterestingly, the two transitions seem to be disconnected. We also discuss a\npotential dynamical mechanism that may explain this behavior."
    },
    {
        "anchor": "Some Non-Perturbative Aspects of Gauge Fixing in Two Dimensional\n  Yang-Mills Theory: Gauge fixing in general is incomplete, such that one solves some of the gauge\nconstraints, quantizes, then imposes any residual gauge symmetries (Gribov\ncopies) on the wavefunctions. While the Fadeev-Popov determinant keeps track of\nthe local metric on this gauge fixed surface, the global topology of the\nreduced configuration space can be different depending on the treatment of the\nresidual symmetries, which can in turn affect global properties of the theory\nsuch as the vacuum wavefunction. Pure $SU(N)$ gauge theory in two dimensions\nprovides a simple yet non-trivial example where the above structure and effects\ncan be elucidated explicitly, thus displaying physical effects of the treatment\nof Gribov copies.",
        "positive": "A Comparative Analysis between Unbiased Exponential Resummation and\n  Taylor Expansion in Finite-Density QCD with a new phasefactor for Isospin: The recently introduced unbiased exponential resummation at finite chemical\npotential has become an important approach which promises to capture reliably\nthe behaviour of higher order conserved charge cumulants appearing otherwise in\nthe finite-density QCD Taylor series of thermodynamic observables. In this\npaper, we present a thorough analysis of the estimates of charge cumulants upto\neighth order and have compared them using Taylor expansion method and unbiased\nexponential resummation approach for baryon and isospin chemical potentials. We\nalso subsequently compare the different estimates of the radius of convergence\nobtained using these two methods and check if the zeros of phasefactor for\nbaryochemical potential can indicate something about these estimated values. We\npropose a new method of finding a non-trivial phasefactor for isospin chemical\npotential and we attempt explaining the different estimates of radius of\nconvergence from the zeroes of this newly constructed gauge-ensemble average\nphasefactor for isospin chemical potential. Lastly, we also illustrate kurtosis\nplots describing the behaviour of overlap problem in isospin chemical potential\nand check if it maintains consistency with the appearance of zeros of the newly\nproposed phasefactor."
    },
    {
        "anchor": "Glueballs on S^3: For SU(2) gauge theory on the three-sphere we study the dynamics of the\nlow-energy modes. By explicitely integrating out the high-energy modes, the\none-loop correction to the hamiltonian for this problem is obtained. After\nimposing the $\\theta$-dependence through boundary conditions in configuration\nspace, we obtain the glueball spectrum of the effective theory with a\nvariational method.",
        "positive": "Density of States of the lattice Schwinger model: Using a recently introduced tensor network method, we study the density of\nstates of the lattice Schwinger model, a standard testbench for lattice gauge\ntheory numerical techniques, but also the object of recent experimental quantum\nsimulations. We identify regimes of parameters where the spectrum appears to be\nsymmetric and displays the expected continuum properties even for finite\nlattice spacing and number of sites. However, we find that for moderate system\nsizes and lattice spacing of $ga\\sim O(1)$, the spectral density can exhibit\nvery different properties with a highly asymmetric form. We also explore how\nthe method can be exploited to extract thermodynamic quantities."
    },
    {
        "anchor": "Linked Cluster Expansions on non-trivial topologies: Linked cluster expansions provide a useful tool both for analytical and\nnumerical investigations of lattice field theories. The expansion parameter is\nthe interaction strength fields at neighboured lattice sites are coupled. They\nresult into convergent series for free energies, correlation functions and\nsusceptibilities. The expansions have been generalized to field theories at\nfinite temperature and to a finite volume. Detailed information on critical\nbehaviour can be extracted from the high order behaviour of the susceptibility\nseries. We outline some of the steps by which the 20th order is achieved.",
        "positive": "Four-point renormalized coupling constant in O(N) models: The renormalized zero-momentum four-point coupling $g_r$ of $O(N)$-invariant\nscalar field theories in $d$ dimensions is studied by applying the $1/N$\nexpansion and strong coupling analysis. The $O(1/N)$ correction to the\n$\\beta$-function and to the fixed point value $g_r^*$ are explictly computed.\nStrong coupling series for lattice non-linear $\\sigma$ models are analyzed near\ncriticality in $d=2$ and $d=3$ for several values of $N$ and the corresponding\nvalues of $g_r^*$ are extracted. Large-$N$ and strong coupling results are\ncompared with each other, finding a good general agreement. For small $N$ the\nstrong coupling analysis in 2-d gives the best determination of $g^*_r$ to date\n(or comparable for $N=2,3$ with the available Monte Carlo estimates), and in\n3-d it is consistent with available $\\phi^4$ field theory results."
    },
    {
        "anchor": "Supersymmetric quantum mechanics on the lattice: II. Exact results: Simulations of supersymmetric field theories with spontaneously broken\nsupersymmetry require in addition to the ultraviolet regularisation also an\ninfrared one, due to the emergence of the massless Goldstino. The intricate\ninterplay between ultraviolet and infrared effects towards the continuum and\ninfinite volume limit demands careful investigations to avoid potential\nproblems. In this paper -- the second in a series of three -- we present such\nan investigation for ${\\cal N}=2$ supersymmetric quantum mechanics formulated\non the lattice in terms of bosonic and fermionic bonds. In one dimension, the\nbond formulation allows to solve the system exactly, even at finite lattice\nspacing, through the construction and analysis of transfer matrices. In the\npresent paper we elaborate on this approach and discuss a range of exact\nresults for observables such as the Witten index, the mass spectra and Ward\nidentities.",
        "positive": "The analysis of Polyakov loop and spin correlators in finite volumes: We derive an analytic expression for point to point correlation functions of\nthe Polyakov loop based on the transfer matrix formalism. The contributions\nfrom the eigenvalues of the transfer matrix including and beyond the mass gap\nare investigated both for the $2d$ Ising model and in finite temperature\n$SU(2)$ gauge theory. We find that the leading matrix element shows similar\nscaling properties in both models. Just above the critical point we obtain for\n$SU(2)$ a Debye screening mass $~\\mu_D/T\\approx4~$, independent of the volume.\nSorry, figures are not included and can be sent by ordinary mail."
    },
    {
        "anchor": "Lattice study of the Boer-Mulders transverse momentum distribution in\n  the pion: The Boer-Mulders transverse momentum-dependent parton distribution (TMD)\ncharacterizes polarized quark transverse momentum in an unpolarized hadron.\nTechniques previously developed for lattice calculations of nucleon TMDs are\napplied to the pion. These techniques are based on the evaluation of matrix\nelements of quark bilocal operators containing a staple-shaped Wilson\nconnection. Results for the Boer-Mulders transverse momentum shift in the pion,\nobtained at a pion mass of $m_{\\pi} = 518\\, \\mbox{MeV} $, are presented and\ncompared to corresponding results in the nucleon.",
        "positive": "The one-flavor quark condensate and related problems: I describe a recent calculation (by me, Hoffmann, Liu, and Schaefer) of the\nchiral condensate in one-flavor QCD using numerical simulations with overlap\nfermions. The condensate is extracted by fitting the distribution of low lying\neigenmodes of the Dirac operator in sectors of fixed topological charge to the\npredictions of Random Matrix Theory. Our results are in excellent agreement\nwith estimates from the orientifold large-N expansion. Much interesting physics\nsurrounds this calculation, which I will highlight."
    },
    {
        "anchor": "Wilson chiral perturbation theory, Wilson-Dirac operator eigenvalues and\n  clover improvement: Chiral perturbation theory for eigenvalue distributions, and equivalently\nrandom matrix theory, has recently been extended to include lattice effects for\nWilson fermions. We test the predictions by comparison to eigenvalue\ndistributions of the Hermitian Wilson-Dirac operator from pure gauge (quenched)\nensembles. We show that the lattice effects are diminished when using clover\nimprovement for the Dirac operator. We demonstrate that the leading Wilson\nlow-energy constants associated with Wilson (clover) fermions can be determined\nusing spectral information of the respective Dirac operator at finite volume.",
        "positive": "The energy-momentum tensor in lattice QCD and the Equation of State: We present a new theoretical and practical strategy to renormalize\nnon-perturbatively the energy-momentum tensor in lattice QCD based on the\nframework of shifted boundary conditions. As a preparatory step for the fully\nnon-perturbative calculation, we apply the strategy at 1-loop order in\nperturbation theory determining the renormalization constants of both the\ngluonic and the fermionic components of the energy-momentum tensor. Using\nshifted boundary conditions, the entropy density of QCD is directly related to\nthe expectation value of the space-time components of the renormalized\nenergy-momentum tensor. We then discuss its practical implementation by\nnumerical simulations of QCD with 3 flavours of Wilson quarks for temperatures\nbetween 2.5 GeV and 80 GeV."
    },
    {
        "anchor": "Detailed Analysis of the Three Quark Potential in SU(3) Lattice QCD: The static three-quark (3Q) potential is studied in detail using SU(3)\nlattice QCD with $12^3 \\times 24$ at $\\beta=5.7$ and $16^3 \\times 32$ at\n$\\beta=5.8$, 6.0 at the quenched level. For more than 300 different patterns of\nthe 3Q systems, we perform the accurate measurement of the 3Q Wilson loop with\nthe smearing method, which reduces excited-state contaminations, and present\nthe lattice QCD data of the 3Q ground-state potential $V_{\\rm 3Q}$. We perform\nthe detailed fit analysis on $V_{\\rm 3Q}$ in terms of the Y-ansatz both with\nthe continuum Coulomb potential and with the lattice Coulomb potential, and\nfind that the lattice QCD data of the 3Q potential $V_{\\rm 3Q}$ are well\nreproduced within a few % deviation by the sum of a constant, the two-body\nCoulomb term and the three-body linear confinement term $\\sigma_{\\rm 3Q} L_{\\rm\nmin}$, with $L_{\\rm min}$ the minimal value of the total length of color flux\ntubes linking the three quarks.\n  From the comparison with the Q-$\\bar {\\rm Q}$ potential, we find a\nuniversality of the string tension as $\\sigma_{\\rm 3Q} \\simeq \\sigma_{\\rm Q\n\\bar Q}$ and the one-gluon-exchange result for the Coulomb coefficients as\n$A_{\\rm 3Q} \\simeq \\frac12 A_{\\rm Q \\bar Q}$. We investigate also the several\nfit analyses with the various ans\\\"atze: the Y-ansatz with the Yukawa\npotential, the $\\Delta$-ansatz and a more general ansatz including the Y and\nthe $\\Delta$ ans\\\"atze in some limits. All these fit analyses support the\nY-ansatz on the confinement part in the 3Q potential $V_{\\rm 3Q}$, although\n$V_{\\rm 3Q}$ seems to be approximated by the $\\Delta$-ansatz with\n$\\sigma_\\Delta \\simeq 0.53 \\sigma$.",
        "positive": "Spinons and holons on the lattice: We point out that the dynamical fermion mass generation in the 3D compact\nU(1) lattice gauge theory with charged fermion and scalar fields (chi-U-phi_3\nmodel) may be of relevance for the spinon-holon theory with local gauge\nsymmetry in the condensed matter physics. However, many properties of the model\nare uncertain, so we make some conjectures to motivate their future\ninvestigation. Most probably, for strong gauge coupling the model is by\nuniversality equivalent to the familiar 3D four-fermion coupling models with\nN_f=2. Available numerical results indicate that at the intermediate and weak\ngauge coupling two universality classes with new interesting physics may arise.\nOne of them is associated with a tricritical point which probably exists in the\nphase diagram of the model. The other one is determined by the dynamical\nfermion mass generation in the compact QED_3, which is insufficiently\nunderstood but of much interest by itself."
    },
    {
        "anchor": "The argument for justification of the complex Langevin method and the\n  condition for correct convergence: The complex Langevin method is a promising approach to the complex-action\nproblem based on a fictitious time evolution of complexified dynamical\nvariables under the influence of a Gaussian noise. Although it is known to have\na restricted range of applicability, the use of gauge cooling made it\napplicable to various interesting cases including finite density QCD in certain\nparameter regions. In this paper, we revisit the argument for justification of\nthe method. In particular, we point out a subtlety in the use of time-evolved\nobservables, which play a crucial role in the previous argument. This requires\nthat the probability of the drift term should fall off exponentially or faster\nat large magnitude. We argue that this is actually a necessary and sufficient\ncondition for the method to be justified. Using two simple examples, we show\nthat our condition tells us clearly whether the results obtained by the method\nare trustable or not. We also discuss a new possibility for the gauge cooling,\nwhich can reduce the magnitude of the drift term directly.",
        "positive": "Investigating vector boson scattering: A fully gauge-invariant study: Vector boson scattering (VBS) plays a central role in the search for new\nphysics at collider experiments such as ATLAS and CMS at the LHC. Usually\npredictions for this kind of process are obtained using mainly perturbative\napproaches in fixed gauges. Here we present a fully gauge-invariant study of\nVBS in the scalar-channel involving three different types of Higgs-like\nparticles characterized by their mass; above (heavy), inside (resonance) or\nbelow (stable) the elastic region. To this end, we combine results obtained in\na reduced SM setup from (augmented) perturbation theory with those from\nnon-perturbative lattice simulations."
    },
    {
        "anchor": "Overlap quark propagator near the physical pion mass: The Landau-gauge quark propagator is calculated using overlap fermions on\n2+1-flavour dynamical fermion gauge fields from the PACS-CS collaboration with\npion mass $m_\\pi \\sim 156\\text{ MeV}$ and spatial volume $\\sim (3 \\text{\nfm})^3.$ The observed features of the mass and renormalisation functions are\ndiscussed, including a comparison with recent results using\n$\\mathcal{O}(a)$-improved Wilson fermions on 2-flavour dynamical gauge fields.",
        "positive": "Novel approach for computing gradients of physical observables: We show that an infinitesimal step of gradient flow can be used for defining\na novel approach for computing gradients of physical observables with respect\nto action parameters. Compared to the commonly used perturbative expansion,\nthis approach does not require calculating any disconnected contribution or\nvacuum expectation value and can provide results up to three orders of\nmagnitudes more precise. On the other hand, it requires a non-trivial condition\nto be satisfied by the flow action, the calculation of its force and its\nLaplacian, and the force of the observable, whose gradient needs to be\nmeasured. As a proof of concept, we measure gradients in $\\beta$ of Wilson\nloops in a four-dimensional SU(3) Yang-Mills theory simulated on a $16^4$\nlattice using the Wilson action."
    },
    {
        "anchor": "Combinatorics of lattice paths with and without spikes: We derive a series of results on random walks on a d-dimensional hypercubic\nlattice (lattice paths). We introduce the notions of terse and simple paths\ncorresponding to the path having no backtracking parts (spikes). These paths\nlabel equivalence classes which allow a rearrangement of the sum over paths.\nThe basic combinatorial quantities of this construction are given. These\nformulas are useful when performing strong coupling (hopping parameter)\nexpansions of lattice models. Some applications are described.",
        "positive": "Three-dimensional $O(N)$-invariant $\u03c6^4$ models at criticality for\n  $N\\ge 4$: We study the $O(N)$-invariant $\\phi^4$ model on the simple cubic lattice by\nusing Monte Carlo simulations. By using a finite size scaling analysis, we\nobtain accurate estimates for the critical exponents $\\nu$ and $\\eta$ for\n$N=4$, $5$, $6$, $8$, $10$, and $12$. We study the model for each $N$ for at\nleast three different values of the parameter $\\lambda$ to control leading\ncorrections to scaling. We compare our results with those obtained by other\ntheoretical methods."
    },
    {
        "anchor": "Determining Sigma - Lambda mixing: SU2 isospin breaking effects in baryon octet (and decuplet) masses are due to\na combination of up and down quark mass differences and electromagnetic\neffects. These mass differences are small. Between the Sigma and Lambda the\nmass splitting is much larger, but this is mostly due to their different\nwavefunctions. However there is now also mixing between these states. We\ndetermine the QCD mixing matrix and hence find the mixing angle and mass\nsplitting.",
        "positive": "Anisotropic lattice QCD studies of penta-quarks and tetra-quarks: Anisotropic lattice QCD studies of penta-quarks(5Q) with J^P=1/2^\\pm and\n3/2^{\\pm} are presented at the quenched level together with tetra-quarks(4Q).\nThe standard gauge action at \\beta=5.75 and O(a) improved quark (clover) action\nwith \\kappa=0.1410(0.010)0.1440 are employed on the anisotropic lattice with\nthe renormalized anisotropy a_s/a_t = 4. The ``hybrid boundary condition(HBC)''\nis adopted to discriminate a compact resonance state from scattering states.\nOnly massive 5Q states are found for J^P=1/2^+ and 3/2^{\\pm}, which cannot be\nidentified as \\Theta^+(1540). A low-lying 5Q state is found for J^P=1/2^- at\nm_{5Q}\\simeq 1.75 GeV, which however turns out to be an NK scattering state\nthrough the HBC analysis. A preliminary result for 4Q states is presented\nsuggesting an existence of a compact 4Q resonance at m_{4Q} \\simeq 1.1 GeV in\nthe idealized SU(4)_f chiral limit."
    },
    {
        "anchor": "Three-body unitarity versus finite-volume $\u03c0^+\u03c0^+\u03c0^+$ spectrum\n  from lattice QCD: Strong three-body interactions above threshold govern the dynamics of many\nexotics and conventional excited mesons and baryons. Three-body finite-volume\nenergies calculated from lattice QCD promise an ab-initio understanding of\nthese systems. We calculate the three-$\\pi^+$ spectrum unraveling the\nthree-body dynamics that is tightly intertwined with the $S$-matrix principle\nof three-body unitarity and compare it with recent lattice QCD results. For\nthis purpose, we develop a formalism for three-body systems in moving frames\nand apply it numerically.",
        "positive": "I=0 scalar channel: Using lattice QCD with dynamical Wilson fermions, we study I=0 and\n$J^{P}=0^{+}$ channel which is constructed by\n$\\frac{1}{\\sqrt{2}}(\\bar{u}u+\\bar{d}d)|0>$, in order to search for the $\\sigma$\nmeson. Our preliminary result shows that the connected and disconnected\ndiagrams contribute to the $\\sigma$ meson propagator in the same order."
    },
    {
        "anchor": "Recent Results from the CP-PACS Collaboration: We present an overview of recent results from the CP-PACS computer on the\nquenched light hadron spectrum and an on-going two-flavour full QCD study. We\nfind that our quenched hadron mass results are compatible with the mass\nformulae predicted by quenched chiral perturbation theory, which we adopt in\nour final analysis. Quenched hadron masses in the continuum limit show\nunambiguous and systematic deviations from experiment. For our two-flavour full\nQCD simulation we present preliminary results on the light hadron spectrum,\nquark masses and the static potential. The question of dynamical sea quark\neffects in these quantities is discussed.",
        "positive": "Potentials between pairs of static-light mesons: We give an update on our ongoing investigations of potentials between pairs\nof static-light mesons in Nf=2 Lattice QCD, in different spin and isospin\nchannels. The question of attraction and repulsion is particularly interesting\nwith respect to the X(3872) charmonium state and charged candidates such as the\nZ+(4430). We employ the nonperturbatively improved Sheikholeslami-Wohlert\nfermion and the Wilson gauge actions at two lattice spacings a approx. 0.084 fm\nand a approx. 0.077 fm with a pseudoscalar mass of mPS approx. 770 MeV and mPS\napprox. 400 MeV respectively. We use stochastic all-to-all propagator\ntechniques, improved by a hopping parameter expansion. The analysis is based on\nthe variational method, utilizing various source and sink interpolators."
    },
    {
        "anchor": "Screening Masses in Dimensionally Reduced (2+1)D Gauge Theory: We discuss the screening masses and residue factorisation of the SU(3) (2+1)D\ntheory in the dimensional reduction formalism. The phase structure of the\nreduced model is also investigated.",
        "positive": "Three particles in a finite volume: The volume-dependence of a shallow three-particle bound state in the cubic\nbox with a size $L$ is studied. It is shown that, in the unitary limit, the\nenergy-level shift from the infinite-volume position is given by $\\Delta E=c\n(\\kappa^2/m)\\,(\\kappa L)^{-3/2}|A|^2 \\exp(-2\\kappa L/\\sqrt{3})$, where $\\kappa$\nis the bound-state momentum and $|A|^2$ denotes the three-body analog of the\nasymptotic normalization constant, which encodes the information about the\nshort-range interactions in the three-body system."
    },
    {
        "anchor": "Vector spectral functions and transport properties in quenched QCD: We present new results on the reconstruction of mesonic spectral functions\nfor three temperatures $1.1T_c$, $1.2T_c$ and $1.4T_c$ in quenched QCD. Making\nuse of non-perturbatively improved clover Wilson valence quarks allows for a\nclean extrapolation of correlator data to the continuum limit. For the case of\nvanishing momentum the spectral function is obtained by fitting the data to a\nwell motivated ansatz, using the full covariance matrix of the continuum\nextrapolated data in the fit. We found that vector correlation function is\nalmost temperature independent in the current temperature window. The\nelectrical conductivity of the hot medium, related to the origin of the vector\nspectral function at zero momentum, is computed from the resulting parameters\nat all three temperatures, leading to an estimate of $0.2C_{em}\\lesssim\n\\sigma/T\\lesssim0.4C_{em}$. The dilepton rates resulting from the obtained\nspectral functions show no significant temperature dependence.",
        "positive": "Critical behavior and monopole density in U(1) lattice gauge theory: Our study of the energy distribution has shown that the strength of the first\norder transition in the four-dimensional compact U(1) lattice gauge theory\ndecreases when the coupling $\\lambda$ of the monopole term increases. The\ndisappearance of the energy gap for sufficiently large values of $\\lambda$\nindicates that the transition ultimately becomes of second order. In our\npresent investigation, based on a finite-size analysis, we show that already at\n$\\lambda= 0.9$ the critical exponent is characteristic of a second-order\ntransition. Interestingly, this exponent turns out to be definitely different\nfrom that of the Gaussian case. We observe that the monopole density becomes\nconstant in the second order region. In addition we find the rather surprising\nresult that the phase transition persists up to very large values of $\\lambda$,\nwhere the transition moves to (large) negative $\\beta$."
    },
    {
        "anchor": "Polyakov loops and monopoles in QCD: Monte-Carlo simulations of abelian projection of $T \\neq 0$ pure lattice QCD\nshow that 1) Polyakov loops written in terms of abelian link fields alone play\na role of an order parameter of deconfinement transition, 2) the abelian\nPolyakov loops are decomposed into contributions from Dirac strings of\nmonopoles and from photons, 3) vanishing of the abelian Polyakov loops in the\nconfinement phase is due to the Dirac strings alone and the photons give a\nfinite contribution in both phases. Moreover, these results appear to hold good\nwith any abelian projection as seen from the studies in the maximally abelian\ngauge and in various unitary gauges.",
        "positive": "Accelerating Dynamical Fermion Computations using the Rational Hybrid\n  Monte Carlo (RHMC) Algorithm with Multiple Pseudofermion Fields: There has been much recent progress in the understanding and reduction of the\ncomputational cost of the Hybrid Monte Carlo algorithm for Lattice QCD as the\nquark mass parameter is reduced. In this letter we present a new solution to\nthis problem, where we represent the fermionic determinant using (n)\npseudofermion fields, each with an (\\nth) root kernel. We implement this within\nthe framework of the Rational Hybrid Monte Carlo (RHMC) algorithm. We compare\nthis algorithm with other recent methods in this area and find it is\ncompetitive with them."
    },
    {
        "anchor": "Canonical Demon Monte Carlo Renormalization Group: We describe a method to compute renormalized coupling constants in a Monte\nCarlo renormalization group calculation. It can be used, e.g., for lattice spin\nor gauge models. The basic idea is to simulate a joint system of block spins\nand canonical demons. Unlike the Microcanonical Renormalization Group of Creutz\net al. it avoids systematical errors in small volumes. We present numerical\nresults for the O(3) nonlinear sigma-model.",
        "positive": "What We Do Understand of Colour Confinement: The status of our understanding of confinement is reviewed. The evidence from\nlattice is that monopole condensation, or dual superconductivity, is at work.\nConfinement is an order-disorder transition. Different monopole species look\nequivalent, indicating that the symmetry of the disordered phase is more\ninteresting that we understand."
    },
    {
        "anchor": "Renormalization group improved action on anisotropic lattices: We study a block spin transformation in the SU(3) lattice gauge theory on\nanisotropic lattices to obtain Iwasaki's renormalization group improved action\nfor anisotropic cases. For the class of actions with plaquette and $1\\times2$\nrectangular terms, we determine the improvement parameters as functions of the\nanisotropy $\\xi= a_s/a_t$. We find that the program of improvement works well\nalso on anisotropic lattices. From a study of an indicator which estimates the\ndistance to the renormalized trajectory, we show that, for the range of the\nanisotropy $\\xi \\approx 1$--4, the coupling parameters previously determined\nfor isotropic lattices improve the theory considerably.",
        "positive": "Studying Hadronic Structure of the Photon in Lattice QCD: We show that the matrix element of a local quark-gluon operator in the photon\nstate, $<\\gamma(k\\lambda)|\\hat O| \\gamma(k\\lambda)>$, can be calculated in\nlattice QCD. The result is generalized to other quantities involving space-like\nphotons, including the transition form factor $\\gamma\\gamma^*\\to \\pi^0$ and the\nvirtual-photon-nucleon Compton amplitude $<\\gamma^*N |\\gamma^*N>$ which can be\nused to define the generalized Drell-Hearn-Gerasimov and Bjorken sum rules."
    },
    {
        "anchor": "Chiral Fermions on the Lattice: The overlap approach to chiral gauge theories on arbitrary $D$--dimensional\nlattices is studied. The doubling problem and its relation to chiral anomalies\nfor $D=2$ and 4 is examined. In each case it is shown that the doublers can be\neliminated and the well known perturbative results for chiral anomalies can be\nrecovered. We also consider the multi--flavour case and give the general\ncriteria for the construction of anomaly free chiral gauge theories on\narbitrary lattices. We calculate the second order terms in a continuum\napproximation to the overlap formula in $D$ dimensions and show that they\ncoincide with the bilinear part of the effective action of $D$--dimensional\nWeyl fermions coupled to a background gauge field. Finally, using the same\nformalism we reproduce the correct Lorentz, diffeomorphism and gauge anomalies\nin the coupling of a Weyl fermion to 2--dimensional gravitational and Maxwell\nfields.",
        "positive": "How well do lattice simulations reproduce the different aspects of the\n  geometric Schwinger model: We compare continuum and lattice formulation of the geometric Schwinger Model\non the torus. The lattice reproduces the $U(1)_A$ anomaly, related to\nnon-trivial topological gauge configurations and zero modes."
    },
    {
        "anchor": "Charmonium-like states with $J^{P}=1^{+}$ and isospin 1: Many mesons with properties incompatible with a $\\bar cc$ structure have\nalready been discovered, e.g. the $Z_c$ mesons with isospin 1. We investigate\nthe spectrum of exotic charmonium-like mesons using lattice QCD. The focus is\non $\\bar cc \\bar qq$ states with $J^{PC}=1^{+\\pm}$ and isospin 1. This is the\nfirst study of four-quark states with these quantum numbers, a non-zero total\nmomentum and two different lattice volumes. We extract the energy levels and\ndetermine the scattering length for $D\\bar D^*$ scattering close to the\nthreshold using L\\\"uscher's formalism. Our preliminary results show that the\nenergy shifts for eigenstates dominated by $D\\bar{D}^*$ are very small in the\n$1^{++}$ channel and consistent with zero in the $1^{+-}$ channel.",
        "positive": "One-loop renormalization factors and mixing coeffecients of bilinear\n  quark operators for improved gluon and quark actions: We calculate one-loop renormalization factors and mixing coefficients of\nbilinear quark operators for a class of gluon actions with six-link loops and\nO(a)-improved quark action. The calculation is carried out by evaluating\non-shell Green's functions of quarks and gluons in the standard perturbation\ntheory. We find a general trend that finite parts of one-loop coefficients are\nreduced approximately by a factor two for the renormalization-group improved\ngluon actions compared with the case of the standard plaquette gluon action."
    },
    {
        "anchor": "Deconfinement transition and monopoles in $T\\neq0$ $SU(2)$ QCD: The role of monopoles in the deconfinement transition is discussed in the\nframework of abelian projection in the maximally abelian gauge in $T\\neq0$\n$SU(2)$ QCD. Only one (or a few near $\\beta_c$) long connected monopole loop\nexists uniformly through the whole lattice in each vacuum configuration in\naddition to some very short loops in the confinement phase and the long loop\ndisappears in the deep deconfinement region. Energy-entropy balance of the long\nloops of maximally extended monopoles explains the existence of the\ndeconfinement transition and reproduces roughly the value of the critical\ntemperature.",
        "positive": "A PNJL Model for Adjoint Fermions with Periodic Boundary Conditions: Recent work on QCD-like theories has shown that the addition of adjoint\nfermions obeying periodic boundary conditions to gauge theories on $R^{3}\\times\nS^{1}$ can lead to a restoration of center symmetry and confinement for\nsufficiently small circumference $L$ of $S^{1}$. At small $L$, perturbation\ntheory may be used reliably to compute the effective potential for the Polyakov\nloop $P$ in the compact direction. Periodic adjoint fermions act in opposition\nto the gauge fields, which by themselves would lead to a deconfined phase at\nsmall $L$. In order for the fermionic effects to dominate gauge field effects\nin the effective potential, the fermion mass must be sufficiently small. This\nindicates that chiral symmetry breaking effects are potentially important. We\ndevelop a Polyakov-Nambu-Jona Lasinio (PNJL) model which combines the known\nperturbative behavior of adjoint QCD models at small $L$ with chiral symmetry\nbreaking effects to produce an effective potential for the Polyakov loop $P$\nand the chiral order parameter $\\bar{\\psi}\\psi$. A rich phase structure emerges\nfrom the effective potential. Our results are consistent with the recent\nlattice simulations of Cossu and D'Elia, which found no evidence for a direct\nconnection between the small-$L$ and large-$L$ confining regions. Nevertheless,\nthe two confined regions are connected indirectly if an extended field theory\nmodel with an irrelevant four-fermion interaction is considered. Thus the\nsmall-$L$ and large-$L$ regions are part of a single confined phase."
    },
    {
        "anchor": "Determination of $\u039b_{\\overline{MS}}$ from quenched and $N_f = 2$\n  dynamical QCD: The scale parameter $\\Lambda_{\\overline{MS}}$ is computed on the lattice in\nthe quenched approximation and for $N_f = 2$ flavors of light dynamical quarks.\nThe dynamical calculation is done with non-perturbatively $O(a)$ improved\nWilson fermions. In the continuum limit we obtain\n$\\Lambda_{\\overline{MS}}^{N_f=0} = 243(1)(10)$ MeV and\n$\\Lambda_{\\overline{MS}}^{N_f=2} = 217(16)(11)$ MeV, respectively.",
        "positive": "Walking signals in Nf=8 QCD on the lattice: We investigate chiral and conformal properties of the lattice QCD with eight\nflavors (Nf=8) through meson spectrum using the Highly Improved Staggered Quark\n(HISQ) action. We also compare our results with those of Nf=12 and Nf=4 which\nwe study on the same systematics. We find that the decay constant F_pi of the\npseudoscalar meson \"pion\" is non-zero, with its mass M_pi consistent with zero,\nboth in the chiral limit extrapolation of the chiral perturbation theory\n(ChPT). We also measure other quantities which we find are in accord with the\npi data results: The rho meson mass is consistent with non-zero in the chiral\nlimit, and so is the chiral condensate, with its value neatly coinciding with\nthat from the Gell-Mann-Oakes-Renner relation in the chiral limit. Thus our\ndata for the Nf=8 QCD are consistent with the spontaneously broken chiral\nsymmetry. Remarkably enough, while the Nf=8 data near the chiral limit are well\ndescribed by the ChPT, those for the relatively large fermion bare mass m_f\naway from the chiral limit actually exhibit a finite-size hyperscaling\nrelation, suggesting a large anomalous dimension gamma_m ~ 1. This implies that\nthere exists a remnant of the infrared conformality, and suggests that a\ntypical technicolor (\"one-family model\") as modeled by the Nf=8 QCD can be a\nwalking technicolor theory having an approximate scale invariance with large\nanomalous dimension gamma_m ~ 1."
    },
    {
        "anchor": "Probing center vortices and deconfinement in $\\mathrm{SU}(2)$ lattice\n  gauge theory with persistent homology: We investigate the use of persistent homology, a tool from topological data\nanalysis, as a means to detect and quantitatively describe center vortices in\n$\\mathrm{SU}(2)$ lattice gauge theory in a gauge-invariant manner. We provide\nevidence for the sensitivity of our method to vortices by detecting a vortex\nexplicitly inserted using twisted boundary conditions in the deconfined phase.\nThis inspires the definition of a new phase indicator for the deconfinement\nphase transition. We also construct a phase indicator without reference to\ntwisted boundary conditions using a simple $k$-nearest neighbours classifier.\nFinite-size scaling analyses of both persistence-based indicators yield\naccurate estimates of the critical $\\beta$ and critical exponent of correlation\nlength $\\nu$ of the deconfinement phase transition.",
        "positive": "Phase transition in finite density and temperature lattice QCD: We investigate the behavior of the chiral condensate in lattice QCD at finite\ntemperature and finite chemical potential. The study was done using two flavors\nof light quarks and with a series of $\\beta$ and $ma$ at the lattice size\n$24\\times12^{2}\\times6$. The calculation was done in the Taylar expansion\nformalism. We are able to calculate the first and second order derivatives of\n$\\langle\\bar{\\psi}\\psi\\rangle$ in both isoscalar and isovector channels. With\nthe first derivatives being small, we find that the second derivatives are\nsizable close to the phase transition and the magnitude of $\\bar{\\psi}\\psi$\ndecreases under the influence of finite chemical potential in both channels."
    },
    {
        "anchor": "Fractal Wilson Loop - Area Law and Gauge Invariance in Next to Leading\n  Order: We consider a fractal Wilson loop $<F_{P}>$ and present physical arguments\nwhy this should be a relevant observable in nature. We show for non-compact\nSU(2) lattice gauge theory in the next to leading order of strong coupling\nexpansion that $<F_{P}>$ obeys an area law behavior and is gauge invariant.",
        "positive": "On the non-perturbative gluon mass and heavy quark physics: We study a recently proposed gauge invariant, non-local pure gauge\nobservable, which is equivalent to the gluon propagator in a certain gauge. The\ncorrelator describes a gluon coupled to static sources and decays with\neigenvalues of the Hamiltonian, permitting a non-perturbative definition of a\ngluonic parton mass. Detailed numerical tests of the observable are performed\nin SU(2) gauge theories in 2+1 dimensions. In a Higgs model it reproduces the\nphysical W-boson mass, while in a confining theory its non-local nature results\nin almost exclusive projection onto torelonic states. However, the gluon mass\ncan also be related to the mass difference between the lowest gluelumps, i.e.\ngluon configurations bound to adjoint sources. Its value is computed in SU(2)\npure gauge theory in 2+1 dimensions to be m_A=0.360(19)g^2, which plays an\nimportant role as \"magnetic mass\" of the four-dimensional theory at high\ntemperatures. The same quantity is found to determine the mass splitting\nbetween vector and scalar mesons in the three-dimensional theory. In SU(3) pure\ngauge theory in 3+1 dimensions the corresponding gluelump splitting yields\nm_A\\approx 370 MeV. Possible relations of this quantity with the QCD heavy\nmeson spectrum are discussed."
    },
    {
        "anchor": "Simplified algorithm for the Worldvolume HMC and the Generalized-thimble\n  HMC: The Worldvolume Hybrid Monte Carlo method (WV-HMC method) [arXiv:2012.08468]\nis a reliable and versatile algorithm towards solving the sign problem.\nSimilarly to the tempered Lefschetz thimble method [arXiv:1703.00861], this\nmethod removes the ergodicity problem inherent in algorithms based on Lefschetz\nthimbles. In addition to this advantage, the WV-HMC method significantly\nreduces the computational cost because one needs not compute the Jacobian of\ndeformation in generating configurations. A crucial step in this method is the\nRATTLE algorithm, which projects at each molecular dynamics step a transported\nconfiguration onto a submanifold (worldvolume) in the complex space. In this\npaper, we simplify the RATTLE algorithm by using a simplified Newton method\nwith an improved initial guess, which can be similarly implemented to the HMC\nalgorithm for the generalized thimble method (GT-HMC method). We perform a\nnumerical test for the convergence of the simplified Newton method, and show\nthat the convergence depends on the system size only weakly. The application of\nthis simplified algorithm to various models will be reported in subsequent\npapers.",
        "positive": "Dynamical fermion mass generation by strong gauge interaction shielded\n  by a scalar field: The strongly coupled lattice gauge models with confined fermion and scalar\nmatter fields, which in a certain phase break dynamically a global chiral\nsymmetry, are reconsidered from the point of view of the existence of heavy\nfermions. If these models are interpreted as describing a new strong force\nbeyond the standard model, such heavy fermions can arise as neutral bound\nstates of the fundamental fermion and scalar. The discussed mechanism could be\nconsidered as an alternative to the Higgs mechanism."
    },
    {
        "anchor": "Loop formulation of the supersymmetric nonlinear O(N) sigma model: We derive the fermion loop formulation for the supersymmetric nonlinear\nO$(N)$ sigma model by performing a hopping expansion using Wilson fermions. In\nthis formulation the fermionic contribution to the partition function becomes a\nsum over all possible closed non-oriented fermion loop configurations. The\ninteraction between the bosonic and fermionic degrees of freedom is encoded in\nthe constraints arising from the supersymmetry and induces flavour changing\nfermion loops. For $N \\ge 3$ this leads to fermion loops which are no longer\nself-avoiding and hence to a potential sign problem. Since we use Wilson\nfermions the bare mass needs to be tuned to the chiral point. For $N=2$ we\ndetermine the critical point and present boson and fermion masses in the\ncritical regime.",
        "positive": "Simulation of 4d N=1 supersymmetric Yang-Mills theory with Symanzik\n  improved gauge action and stout smearing: We report on the results of a numerical simulation concerning the low-lying\nspectrum of four-dimensional N=1 SU(2) Supersymmetric Yang-Mills (SYM) theory\non the lattice with light dynamical gluinos. In the gauge sector the tree-level\nSymanzik improved gauge action is used, while we use the Wilson formulation in\nthe fermion sector with stout smearing of the gauge links in the Wilson-Dirac\noperator. The ensembles of gauge configurations were produced with the Two-Step\nPolynomial Hybrid Monte Carlo (TS-PHMC) updating algorithm. We performed\nsimulations on large lattices up to a size of 24^3 x 48 at $\\beta=1.6$. Using\nQCD units with the Sommer scale being set to r_0 = 0.5 fm, the lattice spacing\nis about a ~ 0.09 fm, and the spatial extent of the lattice corresponds to 2.1\nfm. At the lightest simulated gluino mass the spin-1/2 gluino-glue bound state\nappeared to be considerably heavier than its expected super-partner, the\npseudoscalar bound state. Whether supermultiplets are formed remains to be\nstudied in upcoming simulations."
    },
    {
        "anchor": "Two-Baryon Correlation Functions in 2-flavour QCD: We present first results for two-baryon correlation functions, computed using\n$N_f=2$ flavours of O($a$) improved Wilson quarks, with the aim of explaining\npotential dibaryon bound states, specifically the H-dibaryon. In particular, we\nuse a GEVP to isolate the groundstate using two-baryon (hyperon-hyperon)\ncorrelation functions $\\big(\\langle C_{XY}(t)C_{XY}(0) \\rangle$, where\n$XY=\\Lambda\\Lambda, \\Sigma\\Sigma, N\\Xi, \\cdots\\big)$, each of which has an\noverlap with the H-dibaryon. We employ a `blocking' algorithm to handle the\nlarge number of contractions, which may easily be extended to N-baryon\ncorrelation functions. We also comment on its application to the analysis of\nsingle baryon masses ($n$, $\\Lambda$, $\\Xi$, $\\cdots$). This study is performed\non an isotropic lattice with $m_\\pi = 460$ MeV, $m_\\pi L = 4.7$ and $a = 0.063$\nfm.",
        "positive": "Hadron masses and matrix elements from the QCD Schr\"odinger functional: We explain how masses and matrix elements can be computed in lattice QCD\nusing Schr\"odinger functional boundary conditions. Numerical results in the\nquenched approximation demonstrate that good precision can be achieved. For a\nstatistical sample of the same size, our hadron masses have a precision similar\nto what is achieved with standard methods, but for the computation of matrix\nelements such as the pseudoscalar decay constant the Schr\"odinger functional\ntechnique turns out to be much more efficient than the known alternatives."
    },
    {
        "anchor": "Universal formula for the energy--momentum tensor via a flow equation in\n  the Gross--Neveu model: For the fermion field in the two-dimensional Gross--Neveu model, we introduce\na flow equation that allows a simple $1/N$ expansion. By employing the $1/N$\nexpansion, we examine the validity of a universal formula for the\nenergy--momentum tensor which is based on the small flow-time expansion. We\nconfirm that the formula reproduces a correct normalization and the\nconservation law of the energy--momentum tensor by computing the translation\nWard--Takahashi relation in the leading non-trivial order in the $1/N$\nexpansion. Also, we confirm that the expectation value at finite temperature\ncorrectly reproduces thermodynamic quantities. These observations support the\nvalidity of a similar construction of the energy--momentum tensor via the\ngradient/Wilson flow in lattice gauge theory.",
        "positive": "Scaling in the two-dimensional U(1)--Higgs model: We study the continuum limit of the $2D$ U(1)--Higgs model with variable\nscalar field length, which is qualitatively different from the fixed length\ncase. Our simulations concentrate on the scaling behaviour of the topological\nsusceptibility, and an instanton-induced confinement mechanism of fractional\ncharges is numerically confirmed."
    },
    {
        "anchor": "Controlling Excited-State Contributions with Distillation in Lattice QCD\n  Calculations of Nucleon Isovector Charges $g_S^{u-d}$, $g_A^{u-d}$,\n  $g_T^{u-d}$: We investigate the application of the distillation smearing approach, and the\nuse of the variational method with an extended basis of operators facilitated\nby this approach, on the calculation of the nucleon isovector charges\n$g_S^{u-d}$, $g_A^{u-d}$, and $g_T^{u-d}$. We find that the better sampling of\nthe lattice enabled through the use of distillation yields a substantial\nreduction in the statistical uncertainty in comparison with the use of\nalternative smearing methods, and furthermore, appears to offer better control\nover the contribution of excited-states compared to use of a single, local\ninterpolating operator. The additional benefit arising through the use of the\nvariational method in the distillation approach is less dramatic, but\nnevertheless significant given that it requires no additional Dirac inversions.",
        "positive": "Nucleon structure with pion mass down to 149 MeV: We present isovector nucleon observables: the axial, tensor, and scalar\ncharges and the Dirac radius. Using the BMW clover-improved Wilson action and\npion masses as low as 149 MeV, we achieve good control over chiral\nextrapolation to the physical point. Our analysis is done using three different\nsource-sink separations in order to identify excited-state effects, and we make\nuse of the summation method to reduce their size."
    },
    {
        "anchor": "Spectrum of QCD at Finite Isospin Density: We study the phase diagram of QCD at finite isospin density using two flavors\nof staggered quarks. We investigate the low temperature region of the phase\ndiagram where we find a pion condensation phase at high chemical potential. We\nstarted a basic analysis of the spectrum at finite isospin density. In\nparticular, we measured pion, rho and nucleon masses inside and outside of the\npion condensation phase. In agreement with previous studies in two-color QCD at\nfinite baryon density we find that the Polyakov loop does not depend on the\ndensity in the staggered formulation.",
        "positive": "Isotropic and Anisotropic Lattice Spacing Corrections for I=2 pi-pi\n  Scattering from Effective Field Theory: The calculation of the finite lattice spacing corrections for I=2 pi-pi\nscattering is carried out for isotropic and anisotropic Wilson lattice actions.\nPion masses and decay constants are also determined in this context. These\nresults correct the phase shift calculated from the lattice, which is connected\nto the scattering length and effective range in this low energy scattering\nprocess. When in terms of the lattice-physical parameters for either Wilson\naction, these lattice spacing effects first appear at the next-to-leading order\ncounter-terms."
    },
    {
        "anchor": "Determinant of a new fermionic action on a lattice - (II): We investigate the fermion determinant of a new action on a\n$(1+D)$-dimensional lattice for SU(2) gauge groups. This action possesses the\ndiscrete chiral symmetry and provides $2^D$-component fermions. We also comment\non the numerical results on fermion determinants in the $(1+D)$-dimensional\nSU(3) gauge fields.",
        "positive": "Determination of B*B pi coupling in unquenched QCD: The $B^* B\\pi$ coupling is a fundamental parameter of chiral effective\nLagrangian with heavy-light mesons and can constrain the chiral behavior of\n$f_B$, $B_B$ and the $B\\to \\pi l \\nu$ form factor in the soft pion limit. We\ncompute the $B^* B \\pi $ coupling with the static heavy quark and the\n$O(a)$-improved Wilson light quark. Simulations are carried out with $n_f=2$\nunquenched $12^3\\times 24$ lattices at $\\beta=1.80$ and $16^3\\times 32$\nlattices at $\\beta=1.95$ generated by CP-PACS collaboration. To improve the\nstatistical accuracy, we employ the all-to-all propagator technique and the\nstatic quark action with smeared temporal link variables following the quenched\nstudy by Negishi {\\it et al.}. These methods successfully work also on\nunquenched lattices, and determine the $B^*B\\pi$ coupling with 1--2%\nstatistical accuracy on each lattice spacing."
    },
    {
        "anchor": "On the decoupling of mirror fermions: We study an approach to chiral gauge theories on the lattice that involves\ndecoupling \"mirror\" fermions from a vector-like theory. We have computed the\npolarization tensor in the \"3-4-5\" theory and find a directional discontinuity\nthat appears to be nonzero in the continuum limit. This strongly suggests that\nthe mirror fermions do not decouple.",
        "positive": "The axial charge of the triton from lattice QCD: The axial charge of the triton is investigated using lattice quantum\nchromodynamics (QCD). Extending previous work at heavier quark masses,\ncalculations are performed using three ensembles of gauge field configurations\ngenerated with quark masses corresponding to a pion mass of 450 MeV.\nFinite-volume energy levels for the triton, as well as for the deuteron and\ndiproton systems, are extracted from analysis of correlation functions computed\non these ensembles, and the corresponding energies are extrapolated to infinite\nvolume using finite-volume pionless effective field theory (FVEFT). It is found\nwith high likelihood that there is a compact bound state with the quantum\nnumbers of the triton at these quark masses. The axial current matrix elements\nare computed using background field techniques on one of the ensembles and\nFVEFT is again used to determine the axial charge of the proton and triton. A\nsimple quark mass extrapolation of these results and earlier calculations at\nheavier quark masses leads to a value of the ratio of the triton to proton\naxial charges at the physical quark masses of $g_A^{^{3}{\\rm\nH}}/g_A^p=0.91\\substack{+0.07 \\\\ -0.09}$. This result is consistent with the\nratio determined from experiment and prefers values less than unity (in which\ncase the triton axial charge would be unmodified from that of the proton),\nthereby demonstrating that QCD can explain the modification of the axial charge\nof the triton."
    },
    {
        "anchor": "D-Dbar Mixing in the Standard Model and Beyond from Nf=2 Twisted Mass\n  QCD: We present the first unquenched lattice QCD results for the bag parameters\ncontrolling the short distance contribution to D meson oscillations in the\nStandard Model and beyond. We have used the gauge configurations produced by\nthe European Twisted Mass Collaboration with Nf = 2 dynamical quarks, at four\nlattice spacings and light meson masses in the range 280-500 MeV.\nRenormalization is carried out non-perturbatively with the RI-MOM method. The\nbag-parameter results have been used to constrain New Physics effects in D-Dbar\nmixing, to put a lower bound to the generic New Physics scale and to constrain\noff-diagonal squark mass terms for TeV-scale Supersymmetry.",
        "positive": "Simulating QCD at nonzero baryon density to all orders in the hopping\n  parameter expansion: Progress in simulating QCD at nonzero baryon density requires, amongst\nothers, substantial numerical effort. Here we propose two different expansions\nto all orders in the hopping parameter, preserving the full Yang-Mills action,\nwhich are much cheaper to simulate. We carry out simulations using complex\nLangevin dynamics, both in the hopping expansions and in the full theory, for\ntwo flavours of Wilson fermions, and agreement is seen at sufficiently high\norder in the expansion. These results provide support for the use of complex\nLangevin dynamics to study QCD at nonzero density, both in the full and the\nexpanded theory, and for the convergence of the latter."
    },
    {
        "anchor": "Heavy quarkonium spectroscopy in pNRQCD with lattice QCD input: The charmonium and bottomonium mass spectra are investigated in potential\nnonrelativistic QCD (pNRQCD) with the heavy quark potential computed by lattice\nQCD simulations. The potential consists of a static potential and relativistic\ncorrections classified in powers of the inverse of heavy quark mass m, and the\neffects of the O(1/m) and O(1/m^{2}) spin-orbit corrections on the mass spectra\nare examined systematically. The pattern of the mass spectra is found to be in\nfairly good agreement with experimental data, in which the O(1/m) correction\ngives an important contribution.",
        "positive": "QCD+QED lattice calculation of hadronic decay rates: Isospin is an almost exact symmetry of strong interactions and the\ncorrections to the isosymmetric limit are, in general, at the percent level.\nFor several hadronic quantities relevant for flavour physics phenomenology,\nsuch as pseudoscalar meson masses or the kaon leptonic and semileptonic decay\nrates, these effects are of the same order of magnitude of the uncertainties\nquoted in current large-scale QCD simulations on the lattice and cannot be\nneglected anymore. In this contribution I discuss some recent results for the\nleptonic decay rates of light pseudoscalar mesons obtained by the Soton--RM123\nCollaboration including the leading-order electromagnetic and strong\nisospin-breaking corrections in first principles lattice simulations. The\nadopted strategy is within the reach of present lattice technologies and it\nallows to determine electromagnetic corrections to physical observables for\nwhich delicate cancellations of infrared divergences occur in the intermediate\nsteps of the calculation. The application of the developed method to the study\nof heavy-light meson and semileptonic decay rates is currently underway."
    },
    {
        "anchor": "A semi-variational approach to QCD at finite temperature and baryon\n  density: Recently a new bosonization method has been used to derive, at zero fermion\ndensity, an effective action for relativistic field theories whose partition\nfunction is dominated by fermionic composites, chiral mesons in the case of\nQCD. This approach shares two important features with variational methods: the\nrestriction to the subspace of the composites, and the determination of their\nstructure functions by a variational calculation. But unlike standard\nvariational methods it treats excited states at the same time and on the same\nfooting as the ground state. I extend this method including states of\nnonvanishing fermion (baryon) number and derive an effective action for QCD at\nfinite temperature and baryon density. I test the result on a four-fermion\ninteraction model.",
        "positive": "About the Yukawa model on a lattice in the quenched approximation: We study the Yukawa model on a 4-dimensional Euclidean lattice in the\nquenched approximation. A particular attention is given to the singularities of\nthe Dirac operator in the phase diagram. A careful analysis of a particular\nlimiting case shows that size effects can be huge, questioning the quenched\napproximation. This is confirmed by a Monte-Carlo simulation in this limit case\nand without the quenched approximation. We include also some results concerning\nthe symmetries of this model."
    },
    {
        "anchor": "Towards glueball masses of large-$N$ $\\mathrm{SU}(N)$ pure-gauge\n  theories without topological freezing: In commonly used Monte Carlo algorithms for lattice gauge theories the\nintegrated autocorrelation time of the topological charge is known to be\nexponentially-growing as the continuum limit is approached. This\n$\\mathit{topological}\\,\\,\\textit{freezing}$, whose severity increases with the\nsize of the gauge group, can result in potentially large systematics. To\nprovide a direct quantification of the latter, we focus on $\\mathrm{SU}(6)$\nYang--Mills theory at a lattice spacing for which conventional methods\nassociated to the decorrelation of the topological charge have an unbearable\ncomputational cost. We adopt the recently proposed\n$\\mathit{parallel}\\,\\,\\mathit{tempering}\\,\\,\\mathit{on}\\,\\,\\mathit{boundary}\\,\\,\\mathit{conditions}$\nalgorithm, which has been shown to remove systematic effects related to\ntopological freezing, and compute glueball masses with a typical accuracy of\n$2-5\\%$. We observe no sizeable systematic effect in the mass of the first\nlowest-lying glueball states, with respect to calculations performed at\nnearly-frozen topological sector.",
        "positive": "Finite ma corrections for sea quark matrix elements: We discuss the finite $ma$ corrections associated with the computation of sea\nquark matrix elements. We find them to differ from the standard normalization\nused for valence quarks and to depend strongly on the Lorentz structure of the\ncurrent under consideration. Phenomenological implications of these results are\nbriefly discussed in two examples. We also mention how the magnitude of the\ncorrection factors can be reduced by using a 2-link improved action."
    },
    {
        "anchor": "Crossing the Gribov horizon: an unconventional study of geometric\n  properties of gauge-configuration space in Landau gauge: We prove a lower bound for the smallest nonzero eigenvalue of the\nLandau-gauge Faddeev-Popov matrix in Yang-Mills theories. The bound is written\nin terms of the smallest nonzero momentum on the lattice and of a parameter\ncharacterizing the geometry of the first Gribov region. This allows a simple\nand intuitive description of the infinite-volume limit in the ghost sector. In\nparticular, we show how nonperturbative effects may be quantified by the rate\nat which typical thermalized and gauge-fixed configurations approach the Gribov\nhorizon. Our analytic results are verified numerically in the SU(2) case\nthrough an informal, free and easy, approach. This analysis provides the first\nconcrete explanation of why the so-called scaling solution of the\nDyson-Schwinger equations is not observed in lattice studies.",
        "positive": "Computing the topological susceptibility from fixed topology QCD\n  simulations: The topological susceptibility is an important quantity in QCD, which can be\ncomputed using lattice methods. However, at a fine lattice spacing, or when\nusing high quality chirally symmetric quarks, algorithms which proceed in small\nupdate steps --- in particular the HMC algorithm --- tend to get stuck in a\nsingle topological sector. In such cases, the computation of the topological\nsusceptibility is not straightforward. Here, we explore two methods to extract\nthe topological susceptibility from lattice QCD simulations restricted to a\nsingle topological sector. The first method is based on the correlation\nfunction of the topological charge density, while the second method relies on\nmeasuring the topological charge within spacetime subvolumes. Numerical results\nfor two-flavor QCD obtained by using both methods are presented."
    },
    {
        "anchor": "The infrared regime of SU(2) with one adjoint Dirac flavour: SU(2) gauge theory with one Dirac flavour in the adjoint representation is\ninvestigated on a lattice. Initial results for the gluonic and mesonic\nspectrum, static potential from Wilson and Polyakov loops, and the anomalous\ndimension of the fermionic condensate from the Dirac mode number are presented.\nThe results found are not consistent with conventional confining behaviour,\ninstead tentatively pointing towards a theory lying within or very near the\nonset of the conformal window, with the anomalous dimension of the fermionic\ncondensate in the range $0.9 \\lesssim \\gamma_* \\lesssim 0.95$. The implications\nof our work for building a viable theory of strongly interacting dynamics\nbeyond the standard model are discussed.",
        "positive": "On the Interplay of Fermions and Monopoles in Compact QED_3: The infra-red properties of three-dimensional abelian lattice gauge theory\nare known to be governed by a neutral plasma of magnetic monopole excitations.\nWe address the fate of these monopoles in the presence of light dynamical\nfermions, using a lattice formulation of compact QED_3 with N_f=4 fermion\nflavors supplemented by a four-fermi contact term permitting numerical Monte\nCarlo simulations in the chiral limit. Our data hint at a restoration of chiral\nsymmetry above a critical value of the (inverse) coupling beta. By performing\nsimulations in a sector of non-vanishing magnetic charge, we are able to study\nthe response of the theory to an external magnetic test charge. Our results\nsuggest that the monopole plasma persists even once chiral symmetry is\nrestored, and hence survives the continuum limit."
    },
    {
        "anchor": "The lattice scale at large beta in quenched QCD: In this paper we extend the estimate of the value of the lattice spacing a in\nunits of the r0 scale at values of the bare coupling larger than those\navailable. By using results from the computation of the renormalised coupling\nin the Schroedinger functional formalism we find that from beta \\simeq 7 onward\nthe behaviour predicted by asymptotic freedom at tree loop describes very well\nthe data if a value of (r0 Lambda) slightly lower then the latest available is\nused. We also show that, by sticking to the current value, an effective four\nloop term can describe as well the data. The systematic relative error on the\nlattice spacing induced by the choice of the procedure is between 1% and 3% for\n6.92 < beta < 8.5.",
        "positive": "The QCD phase diagram according to the center group: We study an effective theory for QCD at finite temperature and density which\ncontains the leading center symmetric and center symmetry breaking terms. The\neffective theory is studied in a flux representation where the complex phase\nproblem is absent and the model becomes accessible to Monte Carlo techniques\nalso at finite chemical potential. We simulate the system using a generalized\nProkof'ev-Svistunov worm algorithm and compare the results to a low temperature\nexpansion. The phase diagram is determined as a function of temperature,\nchemical potential and quark mass. Shape and quark mass dependence of the phase\nboundaries are as expected for QCD. The transition into the deconfined phase is\nsmooth throughout, without any discontinuities or critical points."
    },
    {
        "anchor": "Density of states approach for lattice field theory with topological\n  terms: We discuss a new density of states (DoS) approach to solve the complex action\nproblem that is caused by topological terms. The key ingredient is to use open\nboundary conditions for (at least) one of the directions, such that the\nquantization of the topological charge is lifted and the density becomes a\nregular function. We employ the DoS FFA method and compute the density of\nstates as a function of the topological charge. Subsequent integration with\nsuitable factors gives rise to the observables we are interested in. We here\nexplore two test cases: U(1) lattice gauge theory in two dimensions, and SU(2)\nlattice gauge theory in four dimensions. Since the 2-d case has an exact\nsolution we may use it to assess the method, in particular to establish the\nequivalence of the open boundary results with the usual choice of periodic\nboundary conditions. The SU(2) case is a first step of developing the\ntechniques towards their eventual application in full QCD.",
        "positive": "Color confinement in Coulomb gauge QCD: We study the long-range behavior of the heavy quark potential in Coulomb\ngauge using a quenched SU(3) lattice gauge simulation with partial-length\nPolyakov line correlators. We show that the Coulomb heavy quark potential\nassociated with the instantaneous part of gluon propagators in Coulomb gauge,\npresents a linearly rising behavior at large distances, and the resulting\nCoulomb string tension is greater than the Wilson loop string tension, which\ncan be explained by Zwanziger's inequality. The linearly rising behavior of the\nCoulomb heavy quark potential persists even in the deconfinement phase. The\nheavy quark potential in Lorentz gauge shows completely different behavior than\nthat in Coulomb gauge. Our SU(3) result, i.e., the Coulomb heavy quark\npotential is confining, qualitatively agrees with that of the SU(2) analysis\ncarried out by Greensite, Olejnik and Zwanziger."
    },
    {
        "anchor": "Studies of Conformal Behavior in Strongly Interacting Quantum Field\n  Theories: In this dissertation, we present work towards characterizing various\nconformal and nearly conformal quantum field theories nonperturbatively using a\ncombination of numerical and analytical techniques. A key area of interest is\nthe conformal window of four dimensional gauge theories with Dirac fermions and\nits potential applicability to beyond the standard model physics.\n  In the first chapter, we review some of the history of models of composite\nHiggs scenarios in order to motivate the study of gauge theories near the\nconformal window. In the second chapter we review lattice studies of a specific\ntheory, SU(3) gauge theory with eight flavors of Dirac fermions in the\nfundamental representation of the gauge group. We place a particular emphasis\non the light flavor-singlet scalar state appearing in the spectrum of this\nmodel and its possible role as a composite Higgs boson. We advocate an approach\nto characterizing nearly conformal gauge theories in which lattice calculations\nare used to identify the best low energy effective field theory (EFT)\ndescription of such nearly conformal gauge theories, and the lattice and EFT\nare then used as complementary tools to classify the generic features of the\nlow energy physics in these theories. We present new results for maximal\nisospin $\\pi\\pi \\rightarrow \\pi\\pi$ scattering on the lattice computed using\nL\\\"uscher's finite volume method. This scattering study is intended to provide\nfurther data for constraining the possible EFT descriptions of nearly conformal\ngauge theory. In Chapter 3, we review the historical development of chiral\neffective theory from current algebra methods up through the chiral Lagrangian\nand modern effective field theory techniques. We present a new EFT framework\nbased on the linear sigma model for describing the low lying states of nearly\nconformal gauge theories. We place a ... (full abstract within)",
        "positive": "Iso-vector axial form factors of the nucleon in two-flavour lattice QCD: We present a lattice calculation of the nucleon iso-vector axial and induced\npseudoscalar form factors on the CLS ensembles using $N_{\\rm f}=2$ dynamical\nflavours of non-perturbatively $\\mathcal{O}(a)$-improved Wilson fermions and an\n$\\mathcal{O}(a)$-improved axial current together with the pseudoscalar density.\nExcited-state effects in the extraction of the form factors are treated using a\nvariety of methods, with a detailed discussion of their respective merits. The\nchiral and continuum extrapolation of the results is performed both using\nformulae inspired by Heavy Baryon Chiral Perturbation Theory (HBChPT) and a\nglobal approach to the form factors based on a chiral effective theory (EFT)\nincluding axial vector mesons. Our results indicate that careful treatment of\nexcited-state effects is important in order to obtain reliable results for the\naxial form factors of the nucleon, and that the main remaining error stems from\nthe systematic uncertainties of the chiral extrapolation. As final results, we\nquote $g_{\\rm A} = 1.278 \\pm 0.068\\genfrac{}{}{0pt}{1}{+0.000}{-0.087}$,\n$\\langle r_{\\rm A}^2\\rangle = 0.360 \\pm\n0.036\\genfrac{}{}{0pt}{1}{+0.080}{-0.088}~\\mathrm{fm}^2$, and $g_{\\rm P} = 7.7\n\\pm 1.8 \\genfrac{}{}{0pt}{1}{+0.8}{-2.0}$ for the axial charge, axial charge\nradius and induced pseudoscalar charge, respectively, where the first error is\nstatistical and the second is systematic."
    },
    {
        "anchor": "Connections between Thin,Thick and Projection Vortices in SU(2) Lattice\n  Gauge Theory: We elucidate the connection between $SO(3) \\times Z(2)$ and the usual SU(2)\nconfiguration variables. By exploiting the freedom of choosing a particular\nSO(3) representative we find a direct connection between the two configuration\nspaces. We are then able to compare the Kovacs-Tomboulis formulation of center\nvortices with the projection vortex formulation on the same configuration.\nChoosing a different representative, and going to the maximal center gauge, we\nshow that projection vortices occur without approximation. The projection\nvortex dominance approximation results from dropping a factor in an exact\nexpression for the Wilson loop.",
        "positive": "Dynamical chirality production in one dimension: We discuss the quantum computation of dynamical chirality production in\nlattice gauge theory. Although the chirality of a lattice fermion is\ncomplicated in general dimensions, it can be simply formulated on a\none-dimensional lattice. The chiral fermion formalism enables us to extract the\nphysical part of the chirality production that would be interpreted as the\nchiral anomaly in the continuous theory. We demonstrate the computation of the\n$Z_2$ lattice gauge theory on a classical emulator."
    },
    {
        "anchor": "Results for light pseudoscalar mesons: We present the current status of the MILC collaboration's calculations of the\nproperties of the light pseudoscalar meson sector. We use asqtad staggered\nensembles with 2+1 dynamical flavors down to $a \\approx 0.045$ fm and light\nquark mass down to 0.05 $m_s$. Here we describe fits to the data using chiral\nforms from SU(3) chiral perturbation theory, including all staggered taste\nviolations at NLO and the continuum NNLO chiral logarithms. We emphasize issues\nof convergence of the chiral expansion.",
        "positive": "Phase Structure Study of SU(2) Lattice Gauge Theory with 8 Flavors: We present the investigation of the strong bare-coupling regime of SU(2)\nlattice gauge theory with 8 fermion flavors in the fundamental representation.\nThe simulations are performed with unimproved staggered fermions and the\nplaquette gauge action. One bulk phase transition is observed through the\nmeasurement of the plaquette. The results of cold-start and hot-start\nsimulations, as well as the hysteresis study, indicate the order of this\ntransition can be weakly first order. Using the smeared Polyakov loops, and a\nmethod inspired by the constraint effective potential, we study the vacuum\nstructure near the confining-deconfining phase transition. The Dirac operator\neigenvalue spectrum is investigated, where further analysis is needed to\nclarify the properties of the chiral phase structure."
    },
    {
        "anchor": "Instanton classical solutions of SU(3) fixed point actions on open\n  lattices: We construct instanton-like classical solutions of the fixed point action of\na suitable renormalization group transformation for the SU(3) lattice gauge\ntheory. The problem of the non-existence of one-instantons on a lattice with\nperiodic boundary conditions is circumvented by working on open lattices. We\nconsider instanton solutions for values of the size (0.6-1.9 in lattice units)\nwhich are relevant when studying the SU(3) topology on coarse lattices using\nfixed point actions. We show how these instanton configurations on open\nlattices can be taken into account when determining a few-couplings\nparametrization of the fixed point action.",
        "positive": "The Phase Diagram of the Three Dimensional Thirring Model: We present Monte Carlo simulation results for the three dimensional Thirring\nmodel on moderate sized lattices using a hybrid molecular dynamics algorithm\nwhich permits an odd or non-integer number Nf of fermion flavors. We find a\ncontinuous chiral symmetry breaking transition for Nf approximately equal to 3\nwith critical exponents consistent with expectations from previous studies. For\nNf=5 the order of the transition is difficult to determine on the lattice sizes\nexplored. We present a phase diagram for the model in the (1/g^2,Nf) plane and\ncontrast our findings with expectations based on approximate solutions of the\ncontinuum Schwinger-Dyson equations."
    },
    {
        "anchor": "Topological Fluctuations in Dense Matter with Two Colors: We study the topological charge fluctuations of an SU(2) lattice gauge theory\ncontaining both N_f=2 and 4 flavors of Wilson fermion, at low temperature with\nnon-zero chemical potential $\\mu$. The topological susceptibility, chi_T, is\nused to characterize differing physical regimes as mu is varied between the\nonset of matter at mu_o and and color deconfinement at mu_d. Suppression of\ninstantons by matter via Debye screening is also investigated, revealing\neffects not captured by perturbative predictions. In particular, the breaking\nof scale invariance leads to the mean instanton size rho becoming mu-dependent\nin the regime between onset and deconfinement, with a scaling rho~1/mu^2 over\nthe range mu_o<mu<mu_d, resulting in an enhancement of chi_T immediately above\nonset.",
        "positive": "Chiral gauge theories with domain wall fermions: We have investigated a proposal to construct chiral gauge theories on the\nlattice using domain wall fermions. The model contains two opposite chirality\nzeromodes, which live on two domain walls. We couple only one of them to a\ngauge field, but find that mirror fermions which also couple to the gauge field\nalways seem to exist."
    },
    {
        "anchor": "Numerical study of ADE-type $\\mathcal{N}=2$ Landau--Ginzburg models: At an extremely low-energy scale, it is believed that the two-dimensional\n$\\mathcal{N}=2$ Wess--Zumino model becomes an $\\mathcal{N}=2$ superconformal\nfield theory (SCFT). We study this theoretical conjecture of the\nLandau--Ginzburg (LG) description by numerical simulations based on a\nsupersymmetric-invariant momentum-cutoff regularization. First, from the\ntwo-point function of the energy-momentum tensor, we measure the central charge\nof the ADE minimal models. Second, we develop a method to take the continuum\nlimit, and perform a precision measurement of the scaling dimension in the\n$A$-type minimal model. All our results show a coherence picture being\nconsistent with the conjectured LG/SCFT correspondence.",
        "positive": "Inclusive hadronic decay rate of the $\u03c4$ lepton from lattice QCD: the\n  $\\bar u s$ flavour channel and the Cabibbo angle: We present a lattice determination of the inclusive decay rate of the process\n$\\tau\\mapsto X_{us} \\nu_\\tau$ in which the $\\tau$ lepton decays into a generic\nhadronic state $X_{us}$ with $\\bar u s$ flavour quantum numbers. Our results\nhave been obtained in $n_f=2+1+1$ iso-symmetric QCD with full non-perturbative\naccuracy, without any OPE approximation and, except for the presently missing\nlong-distance isospin-breaking corrections, include a solid estimate of all\nsources of theoretical uncertainties. This has been possible by using the\nHansen-Lupo-Tantalo method [1] that we have already successfully applied in [2]\nto compute the inclusive decay rate of the process $\\tau\\mapsto X_{ud}\n\\nu_\\tau$ in the $\\bar u d$ flavour channel. By combining our first-principles\ntheoretical results with the presently-available experimental data we extract\nthe CKM matrix element $\\vert V_{us}\\vert$, the Cabibbo angle, with a $0.9$\\%\naccuracy, dominated by the experimental error."
    },
    {
        "anchor": "High Temperature Behavior of the Chern-Simons Diffusion Rate in the 1+1\n  D Abelian Higgs Model: We give arguments that in the 1+1 dimensional abelian Higgs model the\nclassical approximation can be good for the leading high temperature behavior\nof real time processes. The Chern-Simons diffusion rate (`sphaleron rate') is\nstudied numerically in this approximation. New results at high temperature show\na $T^{2/3}$ behavior of the rate at sufficiently small lattice spacing.",
        "positive": "O(1/M^3) effects for heavy-light mesons in lattice NRQCD: The masses of spin-singlet and spin-triplet S-wave mesons containing a single\nheavy quark are computed in the quenched approximation. The light quark action\nand gauge field action are both classically-improved and tadpole-improved, and\nthe couplings to the heavy quark are organized by the 1/M expansion of\ntadpole-improved NRQCD. At each of two lattice spacings, near 0.22fm and\n0.26fm, meson masses are obtained for heavy quarks spanning the region between\ncharmed and bottom mesons. Results up to O(1/M), O(1/M^2) and O(1/M^3) are\ndisplayed separately, so that the convergence of the heavy quark expansion can\nbe discussed. Also, the effect of each term in the O(1/M^3) contribution is\ncomputed individually. For bottom mesons the 1/M-expansion appears to be\nsatisfactory, but the situation for charmed mesons is less clear."
    },
    {
        "anchor": "NLO and NNLO chiral fits for 2+1 flavor DWF ensembles: We study the use of NLO and NNLO formulae from SU(2) chiral perturbation\ntheory to fit results from the 2+1 flavor DWF QCD ensembles that have been\ngenerated by the RBC and UKQCD collaborations. These ensembles are at two\ndifferent lattice spacings, contain multiple dynamical light quark masses, and\ninclude a variety of partially quenched valence quark masses. Both NLO and\ncomplete NNLO fits well represent our data, which has m_pi in the range 220 to\n420 MeV. With our data, the NNLO fits have NLO and NNLO contributions of\nsimilar size, making the series not convergent and the extrapolation to\nphysical light quark masses imprecise. Thus, we use NLO fit results for our\npredictions of f_pi, f_K and the light quark masses.",
        "positive": "Center-Vortex Solutions of the Yang-Mills Effective Action in Three and\n  Four Dimensions: We calculate the one-loop effective action of the SU(2) Yang-Mills theory for\ncenter-vortex configurations, both in 3d and 4d. We find that in both cases\nthere are minima of the effective action, corresponding to vortices of the\ntransverse size approximately 4/g_3^2 and 1.7/Lambda_MS, respectively. The\nvalues of the effective actions at the minima are negative, suggesting that the\nEuclidian vacuum may be unstable with respect to creation of vortices."
    },
    {
        "anchor": "Dynamical Compactification of Extra Dimensions in the Euclidean IKKT\n  Matrix Model via Spontaneous Symmetry Breaking: The IKKT matrix model has been conjectured to provide a promising\nnonperturbative formulation of superstring theory. In this model, spacetime\nemerges dynamically from the microscopic matrix degrees of freedom in the\nlarge-N limit, and Monte Carlo simulations of the Lorentzian version provide\nevidence of an emergent (3+1)-dimensional expanding space-time. In this talk,\nwe discuss the Euclidean version of the IKKT matrix model and provide evidence\nof dynamical compactification of the extra dimensions via the spontaneous\nsymmetry breaking (SSB) of the 10D rotational symmetry. We perform numerical\nsimulations of a system with a severe complex action problem by using the\ncomplex Langevin method (CLM). The CLM suffers from the singular-drift problem\nand we deform the model in order to avoid it. We study the SSB pattern as we\nvary the deformation parameter and we conclude that the original model has an\nSO(3) symmetric vacuum, in agreement with previous calculations using the\nGaussian expansion method (GEM). We employ the GEM to the deformed model and we\nobtain results consistent with the ones obtained by CLM.",
        "positive": "Renormalization of Polyakov loops in different representations and the\n  large-N limit: We study the renormalization of Polyakov loops in different irreducible\nrepresentations of SU(N) Yang-Mills theories at finite temperature, and\ninvestigate their behavior in the large-N limit."
    },
    {
        "anchor": "Transport coefficients of the QGP: The FASTSUM collaboration presents a study on the temperature dependence of\nthe electrical conductivity $\\sigma$ in the quark-gluon plasma, using the\nmethods of lattice QCD. Correlators of the exactly conserved vector current are\nmeasured at different temperatures across the deconfinement transition, using\nensembles of $2+1$ flavours of dynamical fermions on anisotropic lattices. We\nthen employ bayesian methods (MEM) to extract the relevant spectral functions,\nwhich are found to be consistent with $\\sigma/T$ rising as a function of $T$.\nThe robustness of the results is verified by a detailed analysis of the\nsystematics involved in the bayesian reconstruction of the spectral functions.",
        "positive": "The Minimal Landau Background Gauge on the Lattice: We present the first numerical implementation of the minimal Landau\nbackground gauge for Yang-Mills theory on the lattice. Our approach is a simple\ngeneralization of the usual minimal Landau gauge and is formulated for general\nSU(N) gauge group. We also report on preliminary tests of the method in the\nfour-dimensional SU(2) case, using different background fields. Our tests show\nthat the convergence of the numerical minimization process is comparable to the\ncase of a null background. The uniqueness of the minimizing functional employed\nis briefly discussed."
    },
    {
        "anchor": "A quenched study of the Schroedinger functional with chirally rotated\n  boundary conditions: non-perturbative tuning: The use of chirally rotated boundary conditions provides a formulation of the\nSchroedinger functional that is compatible with automatic O(a) improvement of\nWilson fermions up to O(a) boundary contributions. The elimination of bulk O(a)\neffects requires the non-perturbative tuning of the critical mass and one\nadditional boundary counterterm. We present the results of such a tuning in a\nquenched setup for several values of the renormalized gauge coupling, from\nperturbative to non-perturbative regimes, and for a range of lattice spacings.\nWe also check that the correct boundary conditions and symmetries are restored\nin the continuum limit.",
        "positive": "Vus from pi and K decay constants in full lattice QCD with physical u,\n  d, s and c quarks: We determine the decay constants of the pi and K mesons on gluon field\nconfigurations from the MILC collaboration including u, d, s and c quarks. We\nuse three values of the lattice spacing and u/d quark masses going down to the\nphysical value. We use the w_0 parameter to fix the relative lattice spacing\nand f_pi to fix the overall scale. This allows us to obtain a value for\nf{K^+}/f{pi^+} = 1.1916(21). Comparing to the ratio of experimental leptonic\ndecay rates gives |Vus| = 0.22564(28){Br(K^+)}(20){EM}(40){latt}(5){Vud} and\nthe test of unitarity of the first row of the Cabibbo-Kobayashi-Maskawa matrix:\n|Vud|^2+|Vus|^2+|Vub|^2 - 1 = 0.00009(51)."
    },
    {
        "anchor": "Scaling behavior of discretization errors in renormalization and\n  improvement constants: Non-perturbative results for improvement and renormalization constants needed\nfor on-shell and off-shell O(a) improvement of bilinear operators composed of\nWilson fermions are presented. The calculations have been done in the quenched\napproximation at beta=6.0, 6.2 and 6.4. To quantify residual discretization\nerrors we compare our data with results from other non-perturbative\ncalculations and with one-loop perturbation theory.",
        "positive": "Numerical simulation of self-dual U(1) lattice field theory with\n  electric and magnetic matter: We study a recently proposed formulation of U(1) lattice field theory with\nelectric and magnetic matter based on the Villain formulation. This\ndiscretization allows for a duality that gives rise to relations between weak\nand strong gauge coupling. There exists a self-dual value of the gauge coupling\nwhere one may study the model as a function of the remaining matter coupling.\nUsing Monte Carlo simulations based on a worldline/worldsheet representation of\nthe system we evaluate order parameters for spontaneous breaking of\nself-duality. We find that in some interval of the matter coupling self-duality\nbecomes broken spontaneously. We determine the endpoints of this interval and\nstudy the nature of the corresponding critical points. Finally we explore the\nsystem away from the self-dual gauge coupling and show that when crossing the\nself-dual point a first order jump is seen in the order parameters."
    },
    {
        "anchor": "Center vortices as rigid strings: It is shown that the action associated with center vortices in SU(2) lattice\ngauge theory is strongly correlated with extrinsic and internal curvatures of\nthe vortex surface and that this correlation persists in the continuum limit.\nThus a good approximation for the effective vortex action is the action of\nrigid strings, which can reproduce some of the observed geometric properties of\ncenter vortices. It is conjectured that rigidity may be induced by some fields\nlocalized on vortices, and a model-independent test of localization is\nperformed. Monopoles detected in the Abelian projection are discussed as\nnatural candidates for such two-dimensional fields.",
        "positive": "One flavor mass reweighting: foundations: Reweighting is not a new method in lattice QCD, but a comprehensive analysis\nis missing in the literature. We close this gap by presenting: (i) a proof of\nan integral representation of the complex determinant of a complex matrix, (ii)\na method to control the stochastic error of its Monte Carlo estimation, (iii)\nexpansions of the stochastic error and the ensemble fluctuations of the one\nflavor reweighting factor. Based on (iii) we present a detailed scaling\nanalysis and optimized reweighting strategies. As an application we analyze the\nensemble fluctuations of the reweighting factor corresponding to the sea\ncontribution to isospin splitting and predict at physical quark masses a\nstandard deviation of +-20%."
    },
    {
        "anchor": "Parity Realization in Lattice QCD with Ginsparg-Wilson Fermions: The Vafa-Witten arguments on the realization of parity and flavour symmetries\nin the QCD vacuum do not apply to two lattice regularizations of QCD which are\nable to reproduce the chiral anomaly: Wilson fermions and Ginsparg-Wilson\nfermions. We show here how using the last regularization one can get, from\nfirst principles, that the more standard order parameters for these symmetries\ntake a vanishing vacuum expectation value for any number of flavours, if quarks\nhave a non-vanishing mass.",
        "positive": "Insight into nucleon structure from lattice calculations of moments of\n  parton and generalized parton distributions: This talk presents recent calculations in full QCD of the lowest three\nmoments of generalized parton distributions and the insight they provide into\nthe behavior of nucleon electromagnetic form factors, the origin of the nucleon\nspin, and the transverse structure of the nucleon. In addition, new exploratory\ncalculations in the chiral regime of full QCD are discussed."
    },
    {
        "anchor": "Spectral Properties of Quarks in the Quark-Gluon Plasma: We analyze the spectral properties of the quark propagator above the critical\ntemperature for the deconfinement phase transition in quenched lattice QCD\nusing clover improved Wilson fermions. The bare quark mass dependence of the\nquark spectral function is analyzed by varying the hopping parameter \\kappa in\nLandau gauge. We assume a two-pole structure for the quark spectral function,\nwhich is numerically found to work quite well for any value of \\kappa. It is\nshown that in the chiral limit the quark spectral function has two collective\nmodes that correspond to the normal and plasmino excitations, while it is\ndominated by a single-pole structure when the bare quark mass becomes large.",
        "positive": "TUNING TO $N=2$ SUPERSYMMETRY IN THE SU(2) ADJOINT HIGGS-YUKAWA MODEL: The $N=2$ supersymmetric continuum limit is investigated in the SU(2) adjoint\nHiggs-Yukawa model using lattice perturbation theory. In the one-loop\nrenormalization group equations a non-trivial infrared fixed point of coupling\nratios is found. The phase structure at weak couplings is determined by a\nnumerical study of the one-loop effective potential."
    },
    {
        "anchor": "Testing Asymptotic Scaling and Nonabelian Symmetry Enhancement: We determine some points on the finite size scaling curve for the correlation\nlength in the two dimensional O(3) and icosahedron spin models. The Monte Carlo\ndata are consistent with the two models possessing the same continuum limit.\nThe data also suggest that the continuum scaling curve lies above the estimate\nof Kim and of Caracciolo et al and thus leads to larger thermodynamic values of\nof the correlation length than previously reported.",
        "positive": "Closed flux tubes and their string description in D=2+1 SU(N) gauge\n  theories: We carry out lattice calculations of the spectrum of confining flux tubes\nthat wind around a spatial torus of variable length l, in 2+1 dimensions. We\ncompare the energies of the lowest c.30 states to the free string Nambu-Goto\nmodel and to recent results on the universal properties of effective string\nactions. Our most useful calculations are in SU(6) at a small lattice spacing,\nwhich we check is very close to the large-N continuum limit. We find that the\nenergies, En(l), are remarkably close to the predictions of the free string\nNambu-Goto model, even well below the critical length at which the expansion of\nthe Nambu-Goto energy in powers of 1/l diverges and the series needs to be\nresummed. Our analysis of the ground state supports the universality of the\nO(1/l) and the O(1/l^3) corrections to l.sigma, and we find that the deviations\nfrom Nambu-Goto at small l prefer a leading correction that is O(1/l^7),\nconsistent with theoretical expectations. We find that the low-lying states\nthat contain a single phonon excitation are also consistent with the leading\nO(1/l^7) correction dominating down to the smallest values of l. By contrast\nour analysis of the other light excited states clearly shows that for these\nstates the corrections at smaller l resum to a much smaller effective power.\nFinally, and in contrast to our recent calculations in D=3+1, we find no\nevidence for the presence of any non-stringy states that could indicate the\nexcitation of massive flux tube modes."
    },
    {
        "anchor": "Universality check of Abelian Monopoles: We study the Abelian projected SU(2) lattice gauge theory after gauge fixing\nto the maximally Abelian gauge (MAG). In order to check the universality of the\nAbelian dominance we employ the tadpole improved tree level (TI) action. We\nshow that the density of monopoles in the largest cluster (the IR component) is\nfinite in the continuum limit which is approximated already at relatively large\nlattice spacing. The value itself is smaller than in the case of Wilson action.\nWe present results for the ratio of the Abelian to non-Abelian string tension\nfor both Wilson and TI actions for a number of lattice spacings in the range\n0.06 fm < a < 0.35 fm. These results show that the ratio is between 0.9 and\n0.95 for all considered values of lattice couplings and both actions. We\ncompare the properties of the monopole clusters in two gauges - in MAG and in\nthe Laplacian Abelian gauge (LAG). Whereas in MAG the infrared component of the\nmonopole density shows a good convergence to the continuum limit, we find that\nin LAG it is even not clear whether a finite limit exists.",
        "positive": "Gravity and Random Surfaces on the Lattice - A Review: We review recent work in the lattice approach to random surfaces and quantum\ngravity. Our task is made somewhat easier by some very interesting results,\nparticularly in four dimensions, that have appeared recently and which are\nreported elsewhere in these proceedings. Inevitably, given the scope of the\nreview and the limitations of space, the presentation will omit work of\nimportance and be telegraphic in discussing work that is included, for which\napologies are offered in advance. After the customary brief historical\nintroduction we work our way in dimensional order from one up to four\ndimensions before closing with some remarks on the relation, if any, between\nthe various lattice models and ``real'' 4D gravity."
    },
    {
        "anchor": "Renormalization Group Properties of Scalar Field Theory Using Gradient\n  Flow: Gradient flow has proved useful in the definition and measurement of\nrenormalized quantities on the lattice. Recently, the fact that it suppresses\nhigh-modes of the field has been used to construct new, continuous RG\ntransformations both analytically and on the lattice, distinct from the usual\nblocking techniques in spin models and gauge theories. In this work, we discuss\nsuch a formulation for scalar field theory, and we present preliminary\nnumerical results for its application to the determination of critical\nexponents at the Wilson-Fisher fixed point of three-dimensional $\\phi^4$\ntheory.",
        "positive": "Lattice Operators for Moments of the Structure Functions and their\n  Transformation under the Hypercubic Group: For lattice operators that are relevant to the calculation of moments of\nnucleon structure functions we investigate the transformation properties under\nthe hypercubic group. We give explicit bases of irreducible subspaces for\ntensors of rank up to 4."
    },
    {
        "anchor": "Neutral $B$ mixing from 2+1 flavor lattice-QCD: the Standard Model and\n  beyond: We report on the status of our lattice-QCD calculation of the hadronic\ncontribution to $B_d^0$ and $B^0_s$ mixing, with 2+1 flavors of dynamical sea\nquarks. Preliminary results for hadronic mixing matrix elements are given for a\nbasis of five four-quark, dimension-six, $\\Delta B=2$ mixing operators that\nspans the space of all possible hadronic mixing contributions in the Standard\nModel and beyond. At the intermediate stage of analysis reported on in this\nwork, our errors are competitive with published Standard Model matrix element\nresults. For beyond the Standard Model matrix elements, this is the first\nunquenched calculation and the first new lattice-QCD calculation in ten years.",
        "positive": "Complete flavor decomposition of the spin and momentum fraction of the\n  proton using lattice QCD simulations at physical pion mass: We evaluate the gluon and quark contributions to the spin of the proton using\nan ensemble of gauge configuration generated at physical pion mass. We compute\nall valence and sea quark contributions to high accuracy. We perform a\nnon-perturbative renormalization for both quark and gluon matrix elements. We\nfind that the contribution of the up, down, strange and charm quarks to the\nproton intrinsic spin is\n$\\frac{1}{2}\\sum_{q=u,d,s,c}\\Delta\\Sigma^{q^+}=0.191(15)$ and to the total spin\n$\\sum_{q=u,d,s,c}J^{q^+}=0.285(45)$. The gluon contribution to the spin is\n$J^g=0.187(46)$ yielding $J=J^q+J^g=0.473(71)$ confirming the spin sum. The\nmomentum fraction carried by quarks in the proton is found to be $0.618(60)$\nand by gluons $0.427(92)$, the sum of which gives $1.045(118)$ confirming the\nmomentum sum rule. All scale and scheme dependent quantities are given in the\n$\\mathrm{ \\overline{MS}}$ scheme at 2 GeV."
    },
    {
        "anchor": "The role of the Euclidean signature in lattice calculations of\n  quasi-distributions and other non-local matrix elements: Lattice quantum chromodynamics (QCD) provides the only known systematic,\nnonperturbative method for first-principles calculations of nucleon structure.\nHowever, for quantities such as lightfront parton distribution functions (PDFs)\nand generalized parton distributions (GPDs), the restriction to Euclidean time\nprevents direct calculation of the desired observable. Recently, progress has\nbeen made in relating these quantities to matrix elements of spatially\nnonlocal, zero-time operators, referred to as quasidistributions. Even for\nthese time-independent matrix elements, potential subtleties have been\nidentified in the role of the Euclidean signature. In this work, we investigate\nthe analytic behavior of spatially non-local correlation functions and\ndemonstrate that the matrix elements obtained from Euclidean lattice QCD are\nidentical to those obtained using the LSZ reduction formula in Minkowski space.\nAfter arguing the equivalence on general grounds, we also show that it holds in\na perturbative calculation, where special care is needed to identify the\nlattice prediction. Finally we present a proof of the uniqueness of the matrix\nelements obtained from Minkowski and Euclidean correlation functions to all\norder in perturbation theory.",
        "positive": "Numerical Tests of the Improved Fermilab Action: Recently, the Fermilab heavy-quark action was extended to include\ndimension-six and -seven operators in order to reduce the discretization\nerrors. In this talk, we present results of the first numerical simulations\nwith this action (the OK action), where we study the masses of the quarkonium\nand heavy-light systems. We calculate combinations of masses designed to test\nimprovement and compare results obtained with the OK action to their\ncounterparts obtained with the clover action. Our preliminary results show a\nclear improvement."
    },
    {
        "anchor": "Critical or tricritical point in mixed-action SU(2) lattice gauge\n  theory?: An analysis of scaling along the first-order bulk transition line in\nfundamental-adjoint SU(2) lattice gauge theory strongly supports the\nfirst-order endpoint being a tricritical point, and is inconsistent with it\nbeing an ordinary critical point as is usually assumed. If tricritical, the\ntransition must continue from the endpoint further into the phase diagram as a\nsecond-order bulk transition and extend to and beyond the Wilson axis.\nObservations indicate that this is most likely the same transition that has\nbeen traditionally considered a finite-temperature transition.",
        "positive": "Minimal U(1) Gauge Fields in Two Dimensions: Gribov copies of the vacuum in two dimensional compact U(1) lattice gauge\nmodels are constructed. On the basis of this a gauge fixing algorithm is\ndevelopped, wich finds the minimum of the sum of link field squares. Numerical\nexperience in a two dimensional Higgs model with fixed length scalar field is\nreported and the extension to three and four dimensional U(1) and four\ndimensional SU(2) gauge theories is briefly discussed."
    },
    {
        "anchor": "Wilson Fermions, Random Matrix Theory and the Aoki Phase: The QCD partition function for the Wilson Dirac operator, $D_W$, at nonzero\nlattice spacing $a$ can be expressed in terms of a chiral Lagrangian as a\nsystematic expansion in the quark mass, the momentum and $a^2$. Starting from\nthis chiral Lagrangian we obtain an analytical expression for the spectral\ndensity of $\\gamma_5 (D_W+m)$ in the microscopic domain. It is shown that the\n$\\gamma_5$-Hermiticity of the Dirac operator necessarily leads to a coefficient\nof the $a^2$ term that is consistent with the existence of an Aoki phase. The\ntransition to the Aoki phase is explained, and the interplay of the index of\n$D_W$ and nonzero $a$ is discussed. We formulate a random matrix theory for the\nWilson Dirac operator with index $\\nu$ (which, in the continuum limit, becomes\nequal to the topological charge of gauge field configurations). It is shown by\nan explicit calculation that this random matrix theory reproduces the\n$a^2$-dependence of the chiral Lagrangian in the microscopic domain, and that\nthe sign of the $a^2$-term is directly related to the $\\gamma_5$-Hermiticity of\n$D_W$.",
        "positive": "Hadronic decay of a vector meson from the lattice: We explore the decay of a vector meson to two pseudoscalar mesons on the\nlattice with $N_f=2$ flavours of sea quark. Although we are working with quark\nmasses that do not allow a physical decay, we show how the transition rate can\nbe evaluated from the amplitude for $\\rho \\to \\pi \\pi$ and from the\nannihilation component of $\\pi \\pi \\to \\pi \\pi$. We explore the decay amplitude\nfor two different pion momenta and find consistent results. The coupling\nstrength we find is in agreement with experiment. We also find evidence for a\nshift in the $\\rho$ mass caused by mixing with two pion states."
    },
    {
        "anchor": "Optimizing Staggered Multigrid for Exascale performance: Adaptive multi-grid methods have proven very successful in dealing with\ncritical slow down for the Wilson-Dirac solver in lattice gauge theory.\nMulti-grid algorithms developed for Staggered fermions using the K\\\"ahler-Dirac\npreconditioning~\\cite{Brower:2018ymy} have shown remarkable success. In this\nwork, we discuss the performance of this staggered multi-grid algorithm in four\ndimensions. We also demonstrate that offloading some components of a\nmulti-shift solve to a multi-grid solver leads to a significant performance\nimprovement in an existing MILC spectrum workflow on the Summit and Selene\nsupercomputers.",
        "positive": "Three-dimensional $x-y$ model with the Chern-Simons term: We investigate the influence of the Chern-Simons term coupled to the\nthree-dimensional $x-y$ model. This term endows vortices with an internal\nangular momentum and thus gives them arbitrary statistics. The Chern-Simons\nterm for the $x-y$ model takes an integer value which can be written as a sum\nover all vortex lines of the product of the vortex charge and the winding\nnumber of the internal phase angle along that vortex line. We have used the\nMonte-Carlo method to study the three-dimensional $x-y$ model with the\nChern-Simons term. Our findings suggest that this model belongs to the $x-y$\nuniversality class with the critical temperature growing with increasing\ninternal angular momentum."
    },
    {
        "anchor": "Prediction of the Omega_bbb mass from lattice QCD: The mass of the triply heavy baryon Omega_bbb is calculated in lattice QCD\nwith 2+1 flavors of light sea quarks. The b quark is implemented with improved\nlattice NRQCD. Gauge field ensembles from both the RBC/UKQCD and MILC\ncollaborations with lattice spacings in the range from 0.08 fm to 0.12 fm are\nused. The final result for the Omega_bbb mass, which includes an electrostatic\ncorrection, is 14.371+-0.004(stat)+-0.011(syst)+-0.001(exp) GeV. The hyperfine\nsplitting between the physical J=3/2 state and a fictitious J=1/2 state is also\ncalculated.",
        "positive": "Volume reduction in large-N lattice gauge theories [with adjoint\n  fermions]: This work covers volume reduction in quantum field theories on a lattice at\nlarge $N$ (number of colors), as first described by Eguchi and Kawai in 1982.\nThe volume reduction (or volume independence) means that the theory defined on\nan arbitrarily small lattice is equivalent in the large-$N$ limit to the theory\non an infinite lattice with the same bare parameters. We analyze the volume\nreduction by means of Monte Carlo simulations using the lattice model on a\nsingle site (or a small fixed number of sites) with Wilson fermions in the\nadjoint representation, using $N$ up to 60. Most of the results focus on two\nflavours of Dirac fermions and the single fermionic flavour is also discussed\nwhere there is a significant difference of behaviour. We find that the\n$(Z_N)^4$ center symmetry, necessary for the realization of volume reduction,\nis unbroken in the reduced model for a large range of parameters and, in\nparticular, that the maximum admissible value of the adjoint fermion mass is\nnon-zero in the large-$N$ limit. We calculate physical quantities, such as the\nplaquette, the static quark potential and the eigenvalues of the Dirac\noperator. We analyze the finite-$N$ corrections and consider the practicality\nof volume-reduced models in supplementing the large-volume calculations."
    },
    {
        "anchor": "Renormalization of Wilson-line operators in the presence of nonzero\n  quark masses: In this paper, we examine the effect of nonzero quark masses on the\nrenormalization of gauge-invariant nonlocal quark bilinear operators, including\na finite-length Wilson line (called Wilson-line operators). These operators are\nrelevant to the definition of parton quasi-distribution functions, the\ncalculation on the lattice of which allows the direct nonperturbative study of\nthe corresponding physical parton distribution functions. We present our\nperturbative calculations of the bare Green's functions, the renormalization\nfactors in RI' and MSbar schemes, as well as the conversion factors of these\noperators between the two renormalization schemes. Our computations have been\nperformed in dimensional regularization at one-loop level, using massive\nquarks. The conversion factors can be used to convert the corresponding lattice\nnonperturbative results to the MSbar scheme, which is the most widely used\nrenormalization scheme for the analysis of experimental data in high-energy\nphysics. Also, our study is relevant for disentangling the additional operator\nmixing which occurs in the presence of nonzero quark masses, both on the\nlattice and in dimensional regularization.",
        "positive": "New Initial Conditions for Quantum Field Simulations after a Quench: We investigate a new way of using the quantum fluctuations in the vacuum as\ninitial conditions for subsequent classical field dynamics. This method avoids\nproblems with renormalization and leads to better thermalization."
    },
    {
        "anchor": "Equivariant flow-based sampling for lattice gauge theory: We define a class of machine-learned flow-based sampling algorithms for\nlattice gauge theories that are gauge-invariant by construction. We demonstrate\nthe application of this framework to U(1) gauge theory in two spacetime\ndimensions, and find that near critical points in parameter space the approach\nis orders of magnitude more efficient at sampling topological quantities than\nmore traditional sampling procedures such as Hybrid Monte Carlo and Heat Bath.",
        "positive": "Three-dimensional U(1) gauge+Higgs theory as an effective theory for\n  finite temperature phase transitions: We study the three-dimensional U(1)+Higgs theory (Ginzburg-Landau model) as\nan effective theory for finite temperature phase transitions from the 1 K scale\nof superconductivity to the relativistic scales of scalar electrodynamics. The\nrelations between the parameters of the physical theory and the parameters of\nthe 3d effective theory are given. The 3d theory as such is studied with\nlattice Monte Carlo techniques. The phase diagram, the characteristics of the\ntransition in the first order regime, and scalar and vector correlation lengths\nare determined. We find that even rather deep in the first order regime, the\ntransition is weaker than indicated by 2-loop perturbation theory. Topological\neffects caused by the compact formulation are studied, and it is demonstrated\nthat they vanish in the continuum limit. In particular, the photon mass\n(inverse correlation length) is observed to be zero within statistical errors\nin the symmetric phase, thus constituting an effective order parameter."
    },
    {
        "anchor": "The Block Spin Renormalization Group Approach and Two-Dimensional\n  Quantum Gravity: A block spin renormalization group approach is proposed for the dynamical\ntriangulation formulation of two-dimensional quantum gravity. The idea is to\nupdate link flips on the block lattice in response to link flips on the\noriginal lattice. Just as the connectivity of the original lattice is meant to\nbe a lattice representation of the metric, the block links are determined in\nsuch a way that the connectivity of the block lattice represents a block\nmetric. As an illustration, this approach is applied to the Ising model coupled\nto two-dimensional quantum gravity. The correct critical coupling is\nreproduced, but the critical exponent is obscured by unusually large finite\nsize effects.",
        "positive": "Semileptonic Decays of Heavy Mesons: A Status Report: We present intermediate results on our ongoing investigation concerning\nsemileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector\nmesons. The corresponding formfactors are evaluated at several momenta and\nappropriate combinations of four light and four heavy quarks, which are chosen\nto allow for an extrapolation into the B Meson region. In order to obtain clear\ngroundstate signals we apply gauge invariant ``Wuppertal'' smearing to the\nquarks. The analysis is based on 32 quenched gauge configurations of size $24^3\n\\times 64$ at $\\beta=6.3$, with Wilson fermions."
    },
    {
        "anchor": "Making chiral fermion actions (almost) gauge invariant using Laplacian\n  gauge fixing: Straight foreward lattice descriptions of chiral fermions lead to actions\nthat break gauge invariance. I describe a method to make such actions gauge\ninvariant (up to global gauge transformations) with the aid of gauge fixing. To\nmake this prescription unambiguous, Laplacian gauge fixing is used, which is\nfree from Gribov ambiguities.",
        "positive": "Connected and disconnected contributions to nucleon axial form factors\n  using $N_f=2$ twisted mass fermions at the physical point: We present results on the isovector and isoscalar nucleon axial form factors\nincluding disconnected contributions,using an ensemble of $N_f =2$ twisted mass\nclover- improved Wilson fermions simulated with approximately the physical\nvalue of the pion mass. The light disconnected quark loops are computed using\nexact deflation, while the strange and the charm quark loops are evaluated\nusing the truncated solver method. Techniques such as the summation and the\ntwo-state fits have been employed to access ground-state dominance."
    },
    {
        "anchor": "Approaching the conformal window: systematic study of the particle\n  spectrum in SU(2) field theory with Nf=2, 4 and 6: It is expected that SU(2) gauge theory with $N_f$ fundamental fermions has an\ninfrared fixed point when $N_f$ is between $\\sim 6$ and 10. We study the hadron\nspectrum and scale setting in SU(2) gauge field theory with $N_f=2,4,6$ using\nhypercubic stout smeared Wilson-clover (HEX) action. The case $N_f=2$ is\nQCD-like, whereas $N_f=6$ is close to the lower edge of the conformal window.\nIn our study the length scales are determined by using the gradient flow\napproach.",
        "positive": "SU(2) lattice gluon propagator: continuum limit, finite-volume effects\n  and infrared mass scale m_IR: We study the scaling behavior and finite (physical) volume effects as well as\nthe Gribov copy dependence of the SU(2) Landau gauge gluon propagator on the\nlattice. Our physical lattice sizes range from $(3.0 \\mathrm{fm})^4$ to $(7.3\n\\mathrm{fm})^4$. Considering lattices with decreasing lattice spacing but fixed\nphysical volume we confirm (non-perturbative) multiplicative renormalizability\nand the approach to the {\\it continuum limit} for the renormalized gluon\npropagator $D_{ren}(p)$ at momenta $|p| \\ageq 0.6$ GeV >. The finite-volume\neffects and Gribov copy influence turn out small in this region. On the\ncontrary, in the deeper infrared we found the Gribov copy influence strong and\nfinite-volume effects, which still require special attention. The gluon\npropagator does not seem to be consistent with a simple pole-like behavior\n$\\sim (p^2+m_g^2)^{-1}$ for momenta $|p| \\aleq 0.6$ GeV. Instead, a\nGaussian-type fit works very well in this region. From its width - for a\nphysical volume $(5.0 \\mathrm{fm})^4$ - we estimate a corresponding infrared\n(mass) scale to be $m_\\mathrm{IR} \\sim 0.7 $ GeV."
    },
    {
        "anchor": "Finite density phase transition of QCD with $N_f=4$ and $N_f=2$ using\n  canonical ensemble method: In a progress toward searching for the QCD critical point, we study the\nfinite density phase transition of $N_f = 4$ and 2 lattice QCD at finite\ntemperature with the canonical ensemble approach. We develop a winding number\nexpansion method to accurately project out the particle number from the fermion\ndeterminant which greatly extends the applicable range of baryon number sectors\nto make the study feasible. Our lattice simulation was carried out with the\nclover fermions and improved gauge action. For a given temperature, we\ncalculate the baryon chemical potential from the canonical approach to look for\nthe mixed phase as a signal for the first order phase transition. In the case\nof $N_f=4$, we observe an \"S-shape\" structure in the chemical potential-density\nplane due to the surface tension of the mixed phase in a finite volume which is\na signal for the first order phase transition. We use the Maxwell construction\nto determine the phase boundaries for three temperatures below $T_c$. The\nintersecting point of the two extrapolated boundaries turns out to be at the\nexpected first order transition point at $T_c$ with $\\mu = 0$. This serves as a\ncheck for our method of identifying the critical point. We also studied the\n$N_f =2$ case, but do not see a signal of the mixed phase for temperature as\nlow as 0.83 $T_c$.",
        "positive": "Neutron Electric Dipole Moment from quark Chromoelectric Dipole Moment: The connection between a regularization-independent symmetric momentum\nsubstraction (RI-$\\tilde{\\rm S}$MOM) and the $\\overline{\\rm MS}$ scheme for the\nquark chromo EDM operators is discussed. A method for evaluating the neutron\nEDM from quark chromoEDM is described. A preliminary study of the signal in the\nmatrix element using clover quarks on a highly improved staggered quark (HISQ)\nensemble is shown."
    },
    {
        "anchor": "Running Coupling in SU(3) Yang-Mills Theory: We report about our ongoing computation of running coupling constants in\nasymptotically free theories using the recursive finite size scaling technique.\nThe latest results for the SU(3) Yang-Mills theory are presented.",
        "positive": "A Portable High-Quality Random Number Generator for Lattice Field Theory\n  Simulations: The theory underlying a proposed random number generator for numerical\nsimulations in elementary particle physics and statistical mechanics is\ndiscussed. The generator is based on an algorithm introduced by Marsaglia and\nZaman, with an important added feature leading to demonstrably good statistical\nproperties. It can be implemented exactly on any computer complying with the\nIEEE--754 standard for single precision floating point arithmetic."
    },
    {
        "anchor": "Towards higher order numerical stochastic perturbation computation\n  applied to the twisted Eguchi-Kawai model: We have evaluated perturbation coefficients of Wilson loops up to $O(g^8)$\nfor the four-dimensional twisted Eguchi-Kawai model using the numerical\nstochastic perturbation theory (NSPT) in arXiv:1902.09847. In this talk we\npresent a progress report on the higher order calculation up to $O(g^{63})$,\nfor which we apply a fast Fourier transformation (FFT) based convolution\nalgorithm to the multiplication of polynomial matrices in the NSPT aiming for\nhigher order calculation. We compare two implementations with the CPU-only\nversion and the GPU version of the FFT based convolution algorithm, and find a\nfactor 9 improvement on the computational speed of the NSPT algorithm with\nSU($N=225$) at $O(g^{31})$. The perturbation order dependence of the\ncomputational time, we investigate it up to $O(g^{63})$, shows a mild scaling\nbehavior on the truncation order.",
        "positive": "Perturbative renormalization of staggered fermion operators with stout\n  improvement: Application to the magnetic susceptibility of QCD: We calculate the fermion propagator and the quark-antiquark Green's functions\nfor a complete set of ultralocal fermion bilinears, ${{\\cal O}_\\Gamma}$\n[$\\Gamma$: scalar (S), pseudoscalar (P), vector (V), axial (A) and tensor (T)],\nusing perturbation theory up to one-loop and to lowest order in the lattice\nspacing. We employ the staggered action for fermions and the Symanzik Improved\naction for gluons. From our calculations we determine the renormalization\nfunctions for the quark field and for all ultralocal taste-singlet bilinear\noperators. The novel aspect of our calculations is that the gluon links which\nappear both in the fermion action and in the definition of the bilinears have\nbeen improved by applying a stout smearing procedure up to two times,\niteratively. Compared to most other improved formulations of staggered\nfermions, the above action, as well as the HISQ action, lead to smaller taste\nviolating effects. The renormalization functions are presented in the RI$'$\nscheme; the dependence on all stout parameters, as well as on the coupling\nconstant, the number of colors, the lattice spacing, the gauge fixing parameter\nand the renormalization scale, is shown explicitly.\n  We apply our results to a nonperturbative study of the magnetic\nsusceptibility of QCD at zero and finite temperature. In particular, we\nevaluate the \"tensor coefficient\", $\\tau$, which is relevant to the anomalous\nmagnetic moment of the muon."
    },
    {
        "anchor": "Small Instantons in $CP^1$ and $CP^2$ Sigma Models: The anomalous scaling behavior of the topological susceptibility $\\chi_t$ in\ntwo-dimensional $CP^{N-1}$ sigma models for $N\\leq 3$ is studied using the\noverlap Dirac operator construction of the lattice topological charge density.\nThe divergence of $\\chi_t$ in these models is traced to the presence of small\ninstantons with a radius of order $a$ (= lattice spacing), which are directly\nobserved on the lattice. The observation of these small instantons provides\ndetailed confirmation of L\\\"{u}scher's argument that such short-distance\nexcitations, with quantized topological charge, should be the dominant\ntopological fluctuations in $CP^1$ and $CP^2$, leading to a divergent\ntopological susceptibility in the continuum limit. For the $\\CP$ models with\n$N>3$ the topological susceptibility is observed to scale properly with the\nmass gap. These larger $N$ models are not dominated by instantons, but rather\nby coherent, one-dimensional regions of topological charge which can be\ninterpreted as domain wall or Wilson line excitations and are analogous to\nD-brane or ``Wilson bag'' excitations in QCD. In Lorentz gauge, the small\ninstantons and Wilson line excitations can be described, respectively, in terms\nof poles and cuts of an analytic gauge potential.",
        "positive": "Photon propagator, monopoles and the thermal phase transition in 3D\n  compact QED: We investigate the gauge boson propagator in three dimensional compact\nAbelian gauge model in the Landau gauge at finite temperature. The presence of\nthe monopole plasma in the confinement phase leads to appearance of an\nanomalous dimension in the momentum dependence of the propagator. The anomalous\ndimension as well as an appropriate ratio of photon wave function\nrenormalization constants with and without monopoles are observed to be order\nparameters for the deconfinement phase transition. We discuss the relation\nbetween our results and the confining properties of the gluon propagator in\nnon--Abelian gauge theories."
    },
    {
        "anchor": "Looking at the analytic structure of Landau gauge propagators: We report on a study of the analytical structure of the Landau gauge gluon,\nghost and quark propagators taken from lattice simulations using large physical\nvolumes, to better access the IR region, and large gauge ensembles to reduce\nthe statistical uncertainties. The investigation uses Pad\\'e approximants to\nlook at poles and branch cuts for each of the propagators. For the gluon\npropagator we identify complex conjugate poles and a branch point. For the\nghost propagator the procedure identifies a pole at zero momentum and a branch\npoint for Minkowski-like momenta. The quark propagator appears to have a pole\nfor Minkowski-like momenta that is correlated with the pion mass as expected\nfrom PCAC.",
        "positive": "On the Definition of Gauge Field Operators in Lattice Gauge-Fixed\n  Theories: We address the problem of defining the gluon field on the lattice in terms of\nthe natural link variables. Different regularized definitions are shown,\nthrough non perturbative numerical computation, to converge towards the same\ncontinuum renormalized limit."
    },
    {
        "anchor": "Looking for pentaquarks in Lattice QCD: Pentaquark states in lattice QCD probably lie close in energy to two particle\nscattering states. Correctly identifying the resonant state is a challenging,\nyet tractable, problem given the terascale computing facilities available\ntoday. We summarize the initial round of exploratory lattice calculations and\ndiscuss what should be accomplished in the next round.",
        "positive": "Flux tubes at Finite Temperature: In this work, we show the flux tubes of the quark-antiquark and quark-quark\nat finite temperature for SU(3) Lattice QCD. The chromomagnetic and\nchromoelectric fields are calculated above and below the phase transition."
    },
    {
        "anchor": "Confining potential of Y-string on the lattice at finite T: The potential due to a system of three static quark (3Q) is studied using\nSU(3) lattice QCD at finite temperature with Polyakov loops operators. We\nfocused our analysis on the large distance properties of the 3Q potential and\nfound a good fit behavior to the Y-string model formula. In addition to the\nlinearly confining term proportional to the minimal length of the Y-string, we\nobserved that the subleading logarithmic term, which is proportional to\nDedekind eta function and accounts for the Y-string's quantum fluctuations, is\nnecessary to reproduce the quark anti-quark string tension of the corresponding\nmesonic system at finite temperature.",
        "positive": "Sp(4) gauge theories and beyond the standard model physics: We review numerical results for models with gauge group Sp(2N), discussing\nthe glueball spectrum in the large-N limit, the quenched meson spectrum of\nSp(4) with Dirac fermions in the fundamental and in the antisymmetric\nrepresentation and the Sp(4) gauge model with two dynamical Dirac flavours. We\nalso present preliminary results for the meson spectrum in the Sp(4) gauge\ntheory with two fundamental and three antisymmetric Dirac flavours. The main\nmotivation of our programme is to test whether this latter model is viable as a\nrealisation of Higgs compositeness via the pseudo Nambu Goldstone mechanism and\nat the same time can provide partial top compositeness. In this respect, we\nreport and briefly discuss preliminary results for the mass of the composite\nbaryon made with two fundamental and one antisymmetric fermion (chimera\nbaryon), whose physical properties are highly constrained if partial top\ncompositeness is at work. Our investigation shows that a fully non-perturbative\nstudy of Higgs compositeness and partial top compositeness in Sp(4) is within\nreach with our current lattice methodology."
    },
    {
        "anchor": "Probing boundary-corrections to Nambu-Goto open string energy levels in\n  3d SU(2) gauge theory: We measure the energy levels of the excitations of the flux tube between\nstatic quark and antiquark in three-dimensional SU(2) gauge theory. Combining\nexponential error reduction techniques and a variational method we are able to\nreduce the errors for the excited states significantly and to extract excited\nstates in distinct parity and charge conjugation channels. It is conjectured\nthat the infrared behavior (at large q\\bar{q} separation R) of the flux tube is\ngoverned by an effective string theory. Indeed previous simulations show good\nagreement between lattice data and predictions from Nambu-Goto string theory.\nRecently, new results on the effective string theory obtained corrections to\nthe Nambu-Goto predictions and showed that for the open string in three\ndimensions first corrections should appears at order 1/R^4. They correspond to\nboundary terms in the worldsheet field theory. These corrections are presumably\nsmall for the ground state, but significantly larger for the excited states and\nlift the degeneracies of the free theory. Assuming this functional form of the\ncorrection, we obtain for the coefficient b_2=-0.5(2)(2).",
        "positive": "Variance reduction techniques for a quantitative understanding of the\n  \u0394I = 1/2 rule: The role of the charm quark in the dynamics underlying the \\Delta I = 1/2\nrule for kaon decays can be understood by studying the dependence of kaon decay\namplitudes on the charm quark mass using an effective \\Delta S = 1 weak\nHamiltonian in which the charm is kept as an active degree of freedom. Overlap\nfermions are employed in order to avoid renormalization problems, as well as to\nallow access to the deep chiral regime. Quenched results in the GIM limit have\nshown that a significant part of the enhancement is purely due to low-energy\nQCD effects; variance reduction techniques based on low-mode averaging were\ninstrumental in determining the relevant weak effective lowenergy couplings in\nthis case. Moving away from the GIM limit requires the computation of diagrams\ncontaining closed quark loops. We report on our progress to employ a\ncombination of low-mode averaging and stochastic volume sources in order to\ncontrol these contributions. Results showing a significant improvement in the\nstatistical signal are presented."
    },
    {
        "anchor": "The hadronic vacuum polarization contribution to $a_\u03bc$ from full\n  lattice QCD: We determine the contribution to the anomalous magnetic moment of the muon\nfrom the $\\alpha^2_{\\mathrm{QED}}$ hadronic vacuum polarization diagram using\nfull lattice QCD and including $u/d$ quarks with physical masses for the first\ntime. We use gluon field configurations that include $u$, $d$, $s$ and $c$\nquarks in the sea at multiple values of the lattice spacing, multiple $u/d$\nmasses and multiple volumes that allow us to include an analysis of\nfinite-volume effects. We obtain a result for $a_{\\mu}^{\\mathrm{HVP,LO}}$ of\n$667(6)(12)$, where the first error is from the lattice calculation and the\nsecond includes systematic errors from missing QED and isospin-breaking effects\nand from quark-line disconnected diagrams. Our result implies a discrepancy\nbetween the experimental determination of $a_{\\mu}$ and the Standard Model of\n3$\\sigma$.",
        "positive": "Wilson-like fermions and the static B_B parameter with no chirality\n  breaking mixings: I consider the recent proposal by R. Frezzotti and G. Rossi to chirally\nimprove Wilson fermions in such a way that mixings among operators of different\nchirality can be excluded. The method, which is based on the use of twisted\nmass QCD with several replica of valence quarks, is extended here to\nstatic-light systems. The operators relevant for the computation of the B_B\nparameter (in the static approximation) are discussed. In this case the same\nrenormalization pattern as for Ginsparg-Wilson fermions is obtained by a simple\nmodification of the discretization of the action for valence quarks."
    },
    {
        "anchor": "Magnetic form factors of the octet baryons from lattice QCD and chiral\n  extrapolation: We present a 2+1--flavor lattice QCD calculation of the electromagnetic Dirac\nand Pauli form factors of the octet baryons. The magnetic Sachs form factor is\nextrapolated at six fixed values of $Q^2$ to the physical pseudoscalar masses\nand infinite volume using a formulation based on heavy baryon chiral\nperturbation theory with finite-range regularization. We properly account for\nomitted disconnected quark contractions using a partially-quenched effective\nfield theory formalism. The results compare well with the experimental form\nfactors of the nucleon and the magnetic moments of the octet baryons.",
        "positive": "A new scheme for color confinement and violation of the non-Abelian\n  Bianchi identities: A new scheme for color confinement in QCD due to violation of the non-Abelian\nBianchi identities proposed earlier is revised. The violation of the\nnon-Abelian Bianchi identities (VNABI) $J_{\\mu}$ is equal to Abelian-like\nmonopole currents $k_{\\mu}$ defined by the violation of the Abelian-like\nBianchi identities. VNABI satisfies $\\partial_{\\mu}J_{\\mu}=0$. There are\n$N^2-1$ conserved magnetic charges in $SU(N)$ QCD. The charge of each component\nof VNABI is assumed to satisfy the Dirac quantization condition. %%%%% Each\ncolor component of the non-Abelian electric field $E^a$ is squeezed by the\ncorresponding color component of the solenoidal current $J^a_{\\mu}$. Then only\nthe color singlets alone can survive as a physical state and non-Abelian color\nconfinement is realized.\n  Numerical studies are done in the framework of $SU(2)$ lattice gauge theory.\nWe adopt an Abelian-like definition of monopole following DeGrand-Toussaint as\na lattice version of VNABI. To reduce severe lattice artifacts, we introduce\nvarious techniques of smoothing the thermalized vacuum such as the maximal\ncenter gauge (MCG) fixing. We measure the density\n$\\rho(a(\\beta),n)=\\sqrt{(k_n^1)^2+(k_n^2)^2+(k_n^3)^2}/(4\\sqrt{4}Vb^3)$, where\n$k_n^a$ is an $n$ blocked monopole in the color direction $a$ and $b=na(\\beta)$\nis the blocked lattice spacing. Beautiful scaling behaviors are seen when we\nplot $\\rho(a(\\beta),n)$ versus $b=na(\\beta)$. A single universal curve\n$\\rho(b)$ is found from $n=1\\sim 12$, which suggests that $\\rho(a(\\beta),n)$ is\na function of $b=na(\\beta)$ alone. The universal curve seems independent of a\ngauge fixing procedure used to smooth the lattice vacuum when the scaling is\nobtained. The scaling shows that the lattice definition of VNABI has the\ncontinuum limit."
    },
    {
        "anchor": "Zero mode contribution in quarkonium correlators and in-medium\n  properties of heavy quarks: We calculate the low energy contribution to quarkonium correlators in\nEuclidean time in lattice QCD. This contribution was found to give the dominant\nsource of the temperature dependence of the correlators. We have found that the\nlow energy contribution is well described by a quasi-particle model and have\ndetermined the effective temperature dependent heavy quark mass.",
        "positive": "Common features of deconfining and chiral critical points in QCD and the\n  three state Potts model in an external field: In the presented study we investigated the second order endpoints of the\nlines of first order phase transitions which emerge for the QCD in the heavy\nand light quark mass regime and for the three-dimensional three state Potts\nmodel with an external field. We located the endpoints with Binder cumulants\nand constructed the energy-like and ordering field like observables. The joint\nprobability distributions of these scaling fields and the values of the Binder\ncumulant confirm that all three endpoints belong to the universality class of\nthe 3-dimensional Ising model."
    },
    {
        "anchor": "Pion and $\u03c1$-meson screening masses at finite chemical potential in\n  two-flavor lattice QCD with Wilson fermion: We investigate the real and imaginary chemical-potential dependence of pion\nand $\\rho$-meson screening masses in both the confinement and the deconfinement\nregion by using two-flavor lattice QCD. The spatial meson correlators are\ncalculated in the imaginary chemical potential region with lattice QCD\nsimulations. We extract pion and $\\rho$-meson screening masses from the\ncorrelators. The obtained meson screening masses are extrapolated to the real\nchemical potential region by assuming some analytic function. In the real\nchemical potential region, the resulting pion and $\\rho$-meson screening masses\nmonotonically increase as real chemical potential becomes large.",
        "positive": "Hamiltonian domain wall fermions at strong coupling: We apply strong-coupling perturbation theory to gauge theories containing\ndomain-wall fermions in Shamir's surface version. We construct the effective\nHamiltonian for the color-singlet degrees of freedom that constitute the\nlow-lying spectrum at strong coupling. We show that the effective theory is\nidentical to that derived from naive, doubled fermions with a mass term, and\nhence that domain-wall fermions at strong coupling suffer both doubling and\nexplicit breaking of chiral symmetry. Since we employ a continuous fifth\ndimension whose extent tends to infinity, our result applies to overlap\nfermions as well."
    },
    {
        "anchor": "Modified $U(1)$ lattice gauge theory: towards realistic lattice QED: We study properties of the compact $~4D~$ $U(1)$ lattice gauge theory with\nmonopoles {\\it removed}. Employing Monte Carlo simulations we calculate\ncorrelators of scalar, vector and tensor operators at zero and nonzero momenta\n$~\\vec{p}~$. We confirm that the theory without monopoles has no phase\ntransition, at least, in the interval $~0 < \\beta \\leq 2~$. There the photon\nbecomes massless and fits the lattice free field theory dispersion relation\nvery well. The energies of the $~0^{++}~$, $~1^{+-}~$ and $~2^{++}~$ states\nshow a rather weak dependence on the coupling in the interval of $~\\beta~$\ninvestigated, and their ratios are practically constant. We show also a further\nmodification of the theory suppressing the negative plaquettes to improve\ndrastically the overlap with the lowest states (at least, for $~J=1$).",
        "positive": "The spatial string tension in the deconfined phase of three dimensional\n  QCD in the large N limit: We numerically compute the spatial string tension in the deconfined phase of\nthree dimensional QCD in the large N limit. Our results clearly show that the\nstring tension grows linearly with temperature."
    },
    {
        "anchor": "Center vortex model for the infrared sector of Yang-Mills theory: A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic\nvortices represented by (closed) random surfaces, is presented. The model\nquantitatively describes both confinement (including the finite-temperature\ntransition to a deconfined phase) and the topological susceptibility of the\nYang-Mills ensemble. A first (quenched) study of the spectrum of the Dirac\noperator furthermore yields a behavior for the chiral condensate which is\ncompatible with results obtained in lattice gauge theory.",
        "positive": "An iterative method to compute the sign function of a non-Hermitian\n  matrix and its application to the overlap Dirac operator at nonzero chemical\n  potential: The overlap Dirac operator in lattice QCD requires the computation of the\nsign function of a matrix. While this matrix is usually Hermitian, it becomes\nnon-Hermitian in the presence of a quark chemical potential. We show how the\naction of the sign function of a non-Hermitian matrix on an arbitrary vector\ncan be computed efficiently on large lattices by an iterative method. A Krylov\nsubspace approximation based on the Arnoldi algorithm is described for the\nevaluation of a generic matrix function. The efficiency of the method is\nspoiled when the matrix has eigenvalues close to a function discontinuity. This\nis cured by adding a small number of critical eigenvectors to the Krylov\nsubspace, for which we propose two different deflation schemes. The ensuing\nmodified Arnoldi method is then applied to the sign function, which has a\ndiscontinuity along the imaginary axis. The numerical results clearly show the\nimproved efficiency of the method. Our modification is particularly effective\nwhen the action of the sign function of the same matrix has to be computed many\ntimes on different vectors, e.g., if the overlap Dirac operator is inverted\nusing an iterative method."
    },
    {
        "anchor": "What can Lattice QCD theorists learn from NMR spectroscopists?: Euclidean-time hadron correlation functions computed in Lattice QCD (LQCD)\nare modeled by a sum of decaying exponentials, reminiscent of the exponentially\ndamped sinusoid models of free induction decay (FID) in Nuclear Magnetic\nResonance (NMR) spectroscopy. We present our initial progress in studying how\ndata modeling techniques commonly used in NMR perform when applied to LQCD\ndata.",
        "positive": "Conjugate Directions in Lattice Landau and Coulomb Gauge Fixing: We provide details expanding on our implementation of a non-linear conjugate\ngradient method with Fourier acceleration for lattice Landau and Coulomb gauge\nfixing. We find clear improvement over the Fourier accelerated steepest descent\nmethod, with the average time taken for the algorithm to converge to a fixed,\nhigh accuracy, being reduced by a factor of 2 to 4. We show such improvement\nfor the logarithmic definition of the gauge fields here, having already shown\nthis to be the case for a more common definition. We also discuss the\nimplementation of an optimal Fourier accelerated steepest descent method."
    },
    {
        "anchor": "Zero density heavy quark SU(2) gauge theory and the Stefan-Boltzmann\n  limit: SU(2) lattice gauge theory is investigated where the traces of the Wilson\nlines at any lattice point and along each direction is constrained to zero.\nHence, each of the lattice configurations possesses a vanishing density of\nheavy (anti-) quarks. The results are compared with those of pure SU(2) gauge\ntheory which can be interpreted as the grand canonical realization of the heavy\nquark theory where only the ensemble average of the heavy quark density\nvanishes.\n  The static quark anti-quark potential of the constrained theory is obtained\nfrom (spatially smeared) Wilson loops at zero temperature. We find that the\npotential coincides with that of pure SU(2) gauge theory (without constraints).\nHence, the familiar \"running\" of the lattice spacing with beta is recovered.",
        "positive": "Finite-temperature chiral transition in QCD with quarks in the\n  fundamental and adjoint representation: We study the nature of the finite-temperature chiral transition in QCD with\nN_f light quarks in the fundamental and adjoint representation. Universality\nand renormalization-group (RG) arguments show that the possibility of having a\ncontinuous transition is related to the existence of a stable fixed point (FP)\nin the RG flow of a 3D Landau-Ginzburg-Wilson Phi^4 theory with the same chiral\nsymmetry-breaking pattern. The RG flow of these theories is studied by\nfield-theoretical approaches, computing and analyzing high-order perturbative\nseries, up to six loops. According to this RG analysis, the transition in QCD\ncan be continuous only for N_f=2. In this case it belongs to the 3D O(4)\nuniversality class. We also find a stable FP corresponding to a 3D universality\nclass with symmetry breaking U(2)_L x U(2)_R -> U(2)_V, which implies that the\ntransition can be continuous also if the axial-anomaly effects are suppressed\nat Tc. In the case of quarks in the adjoint representation, we can have a\ncontinuous transition for N_f=1,2. For N_f=1 it belongs to the O(3)\nuniversality class. For N_f=2 it belongs to a new 3D universality class\ncharacterized by the symmetry breaking SU(4)->SO(4)."
    },
    {
        "anchor": "Chiral symmetry on the lattice: I review some of the difficulties associated with chiral symmetry in the\ncontext of a lattice regulator. I discuss the structure of Wilson Fermions when\nthe hopping parameter is in the vicinity of its critical value. Here one flavor\ncontrasts sharply with the case of more, where a residual chiral symmetry\nsurvives anomalies. I briefly discuss the surface mode approach, the use of\nmirror Fermions to cancel anomalies, and finally speculate on the problems with\nlattice versions of the standard model.",
        "positive": "Higgs compositeness in $\\mathrm{Sp}(2N)$ gauge theories ---\n  Resymplecticisation, scale setting and topology: As part of an ongoing programme to study $\\mathrm{Sp}(2N)$ gauge theories as\npotential realisations of composite Higgs models, we consider the case of\n$\\mathrm{Sp}(4)$ on the lattice, both as a pure gauge theory, and with two\nDirac fermion flavors in the fundamental representation. In order to compare\nresults between these two cases and maintain control of lattice artefacts, we\nmake use of the gradient flow to set the scale of the simulations. We present\nsome technical aspects of the simulations, including preliminary results for\nthe scale setting in the two cases and results for the topological charge\nhistory."
    },
    {
        "anchor": "The string spectrum from large Wilson loops: We look at energies of the low lying states of the hadronic string in three\ndimensional SU(2) lattice gauge theory by forming correlation matrices among\ndifferent sources. We are able to go to previously inaccessible time\nseparations. This is made possible by using a new algorithm proposed by\nL\\\"{u}scher and Weisz which lets us measure the exponentially small values of\nlarge Wilson loops with sufficient accuracy.",
        "positive": "A worm-inspired algorithm for the simulation of Abelian gauge theories: We present an algorithm in which the all-order strong coupling expansion of\nthe Abelian U(1) gauge theory with Wilson plaquette action is sampled. In\naddition to the vacuum closed surface graphs of the partition function we\npropose to also allow for a class of defects (boundaries) related to Wilson\nloops in the ensemble. The efficiency of our scheme in estimating various\nobservables is compared to a standard Metropolis algorithm."
    },
    {
        "anchor": "Meson Decay Constant Predictions of the Valence Approximation to Lattice\n  QCD: We evaluate $f_{\\pi}/ m_{\\rho}$, $f_K/ m_{\\rho}$, $1/f_{\\rho}$, and $\nm_{\\phi}/(f_{\\phi} m_{\\rho})$, extrapolated to physical quark mass, zero\nlattice spacing and infinite volume, for lattice QCD with Wilson quarks in the\nvalence (quenched) approximation. The predicted $m_{\\phi}/(f_{\\phi} m_{\\rho})$\ndiffers from experiment by less than its statistical uncertainty of\napproximately 15\\%. The other three constants are 10\\% to 20\\% below\nexperiment, equivalent to between one and two times the corresponding\nstatistical uncertainties.",
        "positive": "Confinement in large N gauge theories: We report some recent results obtained for large N gauge theories which\nsupport the idea of volume reduction. Results for the string tension of the\nTwisted Eguchi-Kawai model match with those obtained from extrapolation from\nfinite N. Determination of other observables is currently under way.\nApplication of the twisted reduction idea to the case of 1 or 2 flavours of\nquarks in the adjoint representation of the group offers promising results.\nPreliminary results for the string tension point towards a very different\nbehaviour for 1 and 2 flavours. While the string tension remains finite for 1\nflavour at the critical massless quark limit, it seems to vanish with a large\nanomalous dimension for the $N_f=2$ case. This is consistent with the predicted\nInfrared fixed point expected in the latter case."
    },
    {
        "anchor": "Approaches to the sign problem in lattice field theory: Quantum field theories (QFTs) at finite densities of matter generically\ninvolve complex actions. Standard Monte-Carlo simulations based upon importance\nsampling, which have been producing quantitative first principle results in\nparticle physics for almost fourty years, cannot be applied in this case.\nVarious strategies to overcome this so-called Sign Problem or Complex Action\nProblem were proposed during the last thirty years. We here review the sign\nproblem in lattice field theories, focussing on two more recent methods:\nDualization to world-line type of representations and the density-of-states\napproach.",
        "positive": "Axion phenomenology and $\u03b8$-dependence from $N_f = 2+1$ lattice QCD: We investigate the topological properties of $N_f = 2+1$ QCD with physical\nquark masses, both at zero and finite temperature. We adopt stout improved\nstaggered fermions and explore a range of lattice spacings $a \\sim 0.05 - 0.12$\nfm. At zero temperature we estimate both finite size and finite cut-off\neffects, comparing our continuum extrapolated results for the topological\nsusceptibility $\\chi$ with predictions from chiral perturbation theory. At\nfinite temperature, we explore a region going from $T_c$ up to around $4\\,\nT_c$, where we provide continuum extrapolated results for the topological\nsusceptibility and for the fourth moment of the topological charge\ndistribution. While the latter converges to the dilute instanton gas prediction\nthe former differs strongly both in the size and in the temperature dependence.\nThis results in a shift of the axion dark matter window of almost one order of\nmagnitude with respect to the instanton computation."
    },
    {
        "anchor": "A Novel Non-Perturbative Lattice Regularization of an Anomaly-Free $1 +\n  1d$ Chiral $SU(2)$ Gauge Theory: We present a numerical treatment of a novel non-perturbative lattice\nregularization of a $1+1d$ $SU(2)$ Chiral Gauge Theory. Our approach follows\nrecent proposals that exploit the newly discovered connection between anomalies\nand topological (or entangled) states to show how to create a lattice\nregularization of any anomaly-free chiral gauge theory. In comparison to other\nmethods, our regularization enjoys on-site fermions and gauge action, as well\nas a physically transparent fermion Hilbert space. We follow the `mirror\nfermion' approach, in which we first create a lattice regularization of both\nthe chiral theory and its mirror conjugate and then introduce interactions that\ngap out only the mirror theory. The connection between topological states and\nanomalies shows that such interactions exist if the chiral theory is free of\nall quantum anomalies. Instead of numerically intractable fermion-fermion\ninteractions, we couple the mirror theory to a Higgs field driven into a\nsymmetry-preserving, disordered, gapped phase.",
        "positive": "Quark mass dependence of hadron resonances: We study the dependence of the $D_{s0}(2317)$ mass on the light quark mass\nthrough the analysis of data from QCD lattice simulations. Combining HH$\\chi$PT\nand model selection tools as the LASSO method we fit the lattice data of the\nlow-lying charmed mesons masses, obtaining their extrapolation to the physical\npoint and extracting results for the quark mass dependence of the exotic\nresonances $D_{s0}(2317)$ and $D_{s1}(2460)$, taking as input the energy levels\nfrom a lattice simulation."
    },
    {
        "anchor": "Random matrix analysis of the QCD sign problem for general topology: Motivated by the important role played by the phase of the fermion\ndeterminant in the investigation of the sign problem in lattice QCD at nonzero\nbaryon density, we derive an analytical formula for the average phase factor of\nthe fermion determinant for general topology in the microscopic limit of chiral\nrandom matrix theory at nonzero chemical potential, for both the quenched and\nthe unquenched case. The formula is a nontrivial extension of the expression\nfor zero topology derived earlier by Splittorff and Verbaarschot. Our\nanalytical predictions are verified by detailed numerical random matrix\nsimulations of the quenched theory.",
        "positive": "Perfect Actions with Chemical Potential: We show how to include a chemical potential \\mu in perfect lattice actions.\nIt turns out that the standard procedure of multiplying the quark fields \\Psi,\n\\bar\\Psi at Euclidean time t by \\exp(\\pm \\mu t), respectively, is perfect. As\nan example, the case of free fermions with chemical potential is worked out\nexplicitly. Even after truncation, cut-off effects in the pressure and the\nbaryon density are small. Using a (quasi-)perfect action, numerical QCD\nsimulations for non-zero chemical potential become more powerful, because\ncoarse lattices are sufficient for extracting continuum physics."
    },
    {
        "anchor": "Localised Dirac eigenmodes and Goldstone's theorem at finite temperature: I show that a finite density of near-zero localised Dirac modes can lead to\nthe disappearance of the massless excitations predicted by the\nfinite-temperature version of Goldstone's theorem in the chirally broken phase\nof a gauge theory.",
        "positive": "Approaching the master-field: Hadronic observables in large volumes: The master-field approach to lattice QCD envisions performing calculations on\na small number of large-volume gauge-field configurations. Substantial progress\nhas been made recently in the generation of such fields, and this must be\njoined with measurement strategies that take advantage of the large volume. In\nthese proceedings, we describe how to compute simple hadronic quantities\nefficiently and estimate their errors in the master-field approach, i.e. by\nstudying cross-correlations of observables on a single configuration. We\ndiscuss the scaling of the uncertainty with the volume and compare extractions\nbased on momentum-projected and position-space two-point functions. The latter\nshow promising results, already at intermediate volumes, but come with\nadditional technical complexities such as a more complicated manifestation of\nboundary effects, which we also address."
    },
    {
        "anchor": "A Numerical Study of Improved Quark Actions on Anisotropic Lattices: Tadpole improved Wilson quark actions with clover terms on anisotropic\nlattices are studied numerically.\n  Using asymmetric lattice volumes, the pseudo-scalar meson dispersion\nrelations are measured for 8 lowest lattice momentum modes with quark mass\nvalues ranging from the strange to the charm quark with various values of the\ngauge coupling $\\beta$ and 3 different values of the bare speed of light\nparameter $\\nu$. These results can be utilized to extrapolate or interpolate to\nobtain the optimal value for the bare speed of light parameter $\\nu_{opt}(m)$\nat a given gauge coupling for all bare quark mass values $m$. In particular,\nthe optimal values of $\\nu$ at the physical strange and charm quark mass are\ngiven for various gauge couplings.\n  The lattice action with these optimized parameters can then be used to study\nphysical properties of hadrons involving either light or heavy quarks.",
        "positive": "Chiral symmetry restoration and eigenvalue density of Dirac operator: We reinvestigate constraints on the eigenvalue density of the Dirac operator\nin the chiral symmetric phase of 2 flavor QCD at finite temperature, employing\nthe overlap Dirac operator with the exact chiral symmetry at finite lattice\nspacings to avoid possible ultra-violet(UV) divergences. Studying multi-point\ncorrelation functions in various channels in the thermodynamical limit, we\nobtain stronger constraints than those found in the previous studies that not\nonly the eigenvalue density at the origin but also its first and second\nderivatives vanish in the chiral limit of 2 flavor QCD. In addition we show\nthat the axial U(1) anomaly becomes invisible in susceptibilities of scalar and\npseudo scalar mesons."
    },
    {
        "anchor": "The Perfect Laplace Operator for Non-Trivial Boundaries: The application of Renormalization Group (RG) methods to find perfect\ndiscretizations of partial differential equations is a promising but little\ninvestigated approach. We calculate the classically perfect fixed-point Laplace\noperator for boundaries of non-trivial shape analytically and numerically and\npresent a parametrization that can be used for solving the Poisson equation.",
        "positive": "SMD-based numerical stochastic perturbation theory: The viability of a variant of numerical stochastic perturbation theory, where\nthe Langevin equation is replaced by the SMD algorithm, is examined. In\nparticular, the convergence of the process to a unique stationary state is\nrigorously established and the use of higher-order symplectic integration\nschemes is shown to be highly profitable in this context. For illustration, the\ngradient-flow coupling in finite volume with Schr\\\"odinger functional boundary\nconditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory.\nThe scaling behaviour of the algorithm turns out to be rather favourable in\nthis case, which allows the computations to be driven close to the continuum\nlimit."
    },
    {
        "anchor": "Towards string breaking with 2+1 dynamical fermions using the stochastic\n  LapH method: We investigate the use of stochastically estimated light quark propagators in\ncorrelation functions involving a static color source. To this end we compute\nthe static-light meson pseudoscalar correlation function in the stochastic LapH\nframework, using an ensemble of $N_f= 2+1$ gauge configurations generated\nthrough the CLS effort. We extract the static-light as well as the\nstatic-strange mass with good statistical precision. Together with the static\npotential, we obtain a preliminary estimate for the expected mixing region.",
        "positive": "Lattice Gauge Field Interpolation for Chiral Gauge Theories: The importance of lattice gauge field interpolation for our recent\nnon-perturbative formulation of chiral gauge theory is emphasized. We\nillustrate how the requisite properties are satisfied by our recent\nfour-dimensional non-abelian interpolation scheme, by going through the simpler\ncase of U(1) gauge fields in two dimensions."
    },
    {
        "anchor": "One flavor mass reweighting in lattice QCD: One flavor mass reweighting can be used in lattice QCD computations to fine\ntune the quark masses to their physical values. We present a new method that\nutilizes an unbiased stochastic estimation of the one flavor determinant. The\nstochastic estimation is based on the integral representation of the\ndeterminant of a complex matrix, which we prove. In contrast to other methods\nit can also be applied in situations where the determinant has a complex phase.\nThe stochastic error is controlled by determinant factorizations based on mass\ninterpolation and Schur decomposition. As an example of an application we\ndemonstrate how the method can be used to tune the up-down quark mass\ndifference.",
        "positive": "Multipoint reweighting method and beta functions for the calculation of\n  QCD equation of state: We study a reweighting method aiming at numerical studies of QCD at finite\ndensity, in which the conventional Monte-Carlo method cannot be applied\ndirectly. One of the most important problems in the reweighting method is the\noverlap problem. To solve it, we propose to perform simulations at several\nsimulation points and combine their results in the data analyses. In this\nreport, we introduce this multipoint reweighting method and test if the method\nworks well by measuring histograms of physical quantities. Using this method,\nwe calculate the meson masses as continuous functions of the gauge coupling\nbeta and the hopping parameters kappa in QCD at zero density. We then determine\nlines of constant physics in the (beta, kappa) space and evaluate the\nderivatives of the lattice spacing with respect to beta and kappa along the\nlines of constant physics (inverse of the beta functions), which are needed in\na calculation of the equation of state."
    },
    {
        "anchor": "Equation of state for pure SU(3) gauge theory with renormalization group\n  improved action: A lattice study of the equation of state for pure SU(3) gauge theory using a\nrenormalization-group (RG) improved action is presented. The energy density and\npressure are calculated on a $16^3\\times 4$ and a $32^3\\times 8$ lattice\nemploying the integral method. Extrapolating the results to the continuum\nlimit, we find the energy density and pressure to be in good agreement with\nthose obtained with the standard plaquette action within the error of 3-4%.",
        "positive": "The SU(3) Beta Function from Numerical Stochastic Perturbation Theory: The SU(3) beta function is computed from Wilson loops to 20th order numerical\nstochastic perturbation theory. An attempt is made to include massless\nfermions, whose contribution is known analytically to 4th order. The question\nwhether the theory admits an infrared stable fixed point is addressed."
    },
    {
        "anchor": "Finite Temperature Gauge Theory on Anisotropic Lattices: The finite temperature transition of QCD can be seen as a change in the\nstructure of the hadrons and as a symmetry breaking transition -- a change in\nthe structure of the vacuum. These phenomena are observed differently and carry\ncomplementary information. We aim at a correlated analysis involving hadronic\ncorrelators and the vacuum structure including field and density correlations,\nboth non-trivial questions.",
        "positive": "Inverse Problems in PDF Determinations: The determination of Parton Distribution Functions from a finite set of data\nis a typical example of an inverse problem. Inverse problems are notoriously\ndifficult to solve, in particular when a robust determination of the\nuncertainty in the result is needed. We present a Bayesian framework to deal\nwith this problem and discuss first results from a closure test."
    },
    {
        "anchor": "One loop renormalisation of Lattice NRQCD currents for semileptonic\n  $B\\to D^{(\\ast)}$ decays to order $\\frac{\\vec{p}}{M}$: We present the results of a perturbative calculation to match the axial and\nvector currents for semileptonic $B\\to D^{(\\ast)}$ decays in lattice NRQCD to\nthe continuum \\MSb scheme. The matching is performed to\n$O(\\alpha_s\\frac{\\vec{p}}{M})$ in Feynman gauge and in the on-shell\nrenormalisation scheme.\n  The spatial and temporal components of the currents renormalise differently;\nto this order the matching involves a straightforward renormalisation for the\n$V_0$ and $A_k$ currents, and a rank two and four mixing matrix for the $A_0$\nand $V_k$ currents respectively. The resultant one loop corrections are of\n$O(5%)$, boding well for the accuracy of forthcoming simulations.",
        "positive": "Lattice study of meson correlators in the epsilon-regime of two-flavor\n  QCD: We calculate mesonic two-point functions in the epsilon-regime of two-flavor\nQCD on the lattice with exact chiral symmetry. We use gauge configurations of\nsize 16^3 32 at the lattice spacing a \\sim 0.11 fm generated with dynamical\noverlap fermions. The sea quark mass is fixed at \\sim 3 MeV and the valence\nquark mass is varied in the range 1-4 MeV, both of which are in the\nepsilon-regime. We find a good consistency with the expectations from the\nnext-to-leading order calculation in the epsilon-expansion of (partially\nquenched) chiral perturbation theory. From a fit we obtain the pion decay\nconstant F=87.3(5.6) MeV and the chiral condensate Sigma^{MS}=[239.8(4.0) MeV\n]^3 up to next-to-next-to-leading order contributions."
    },
    {
        "anchor": "Matrix elements of unstable states: Using the language of non-relativistic effective Lagrangians, we formulate a\nsystematic framework for the calculation of resonance matrix elements in\nlattice QCD. The generalization of the L\\\"uscher-Lellouch formula for these\nmatrix elements is derived. We further discuss in detail the procedure of the\nanalytic continuation of the resonance matrix elements into the complex energy\nplane and investigate the infinite-volume limit.",
        "positive": "Comparing SU(2) to SU(3) gluodynamics on large lattices: We study the SU(2) gluon and ghost propagators in Landau gauge on lattices up\nto a size of 112^4. A comparison with the SU(3) case is made and finite-volume\neffects are then investigated. We find that for a large range of momenta the\nSU(2) and SU(3) propagators are remarkably alike. In the low-momentum region we\ncompare with recent results obtained in DSE studies on a 4-torus."
    },
    {
        "anchor": "Sublattice scars and beyond in two-dimensional $U(1)$ quantum link\n  lattice gauge theories: In this article, we elucidate the structure and properties of a class of\nanomalous high-energy states of matter-free $U(1)$ quantum link gauge theory\nHamiltonians using numerical and analytical methods. Such anomalous states,\nknown as quantum many-body scars in the literature, have generated a lot of\ninterest due to their athermal nature. Our starting Hamiltonian is $H =\n\\mathcal{O}_{\\mathrm{kin}} + \\lambda \\mathcal{O}_{\\mathrm{pot}}$, where\n$\\lambda$ is a real-valued coupling, and $\\mathcal{O}_{\\mathrm{kin}}$\n($\\mathcal{O}_{\\mathrm{pot}}$) are summed local diagonal (off-diagonal)\noperators in the electric flux basis acting on the elementary plaquette\n$\\square$. The spectrum of the model in its spin-$\\frac{1}{2}$ representation\non $L_x \\times L_y$ lattices reveal the existence of sublattice scars, $|\\psi_s\n\\rangle$, which satisfy $\\mathcal{O}_{\\mathrm{pot},\\square} |\\psi_s\\rangle =\n|\\psi_s\\rangle$ for all elementary plaquettes on one sublattice and $\n\\mathcal{O}_{\\mathrm{pot},\\square} | \\psi_s \\rangle =0 $ on the other, while\nbeing simultaneous zero modes or nonzero integer-valued eigenstates of\n$\\mathcal{O}_{\\mathrm{kin}}$. We demonstrate a ``triangle relation'' connecting\nthe sublattice scars with nonzero integer eigenvalues of $\n\\mathcal{O}_{\\mathrm{kin}} $ to particular sublattice scars with\n$\\mathcal{O}_{\\mathrm{kin}} = 0$ eigenvalues. A fraction of the sublattice\nscars have a simple description in terms of emergent short singlets, on which\nwe place analytic bounds. We further construct a long-ranged parent Hamiltonian\nfor which all sublattice scars in the null space of $\n\\mathcal{O}_{\\mathrm{kin}} $ become unique ground states and elucidate some of\nthe properties of its spectrum. In particular, zero energy states of this\nparent Hamiltonian turn out to be exact scars of another $U(1)$ quantum link\nmodel with a staggered short-ranged diagonal term.",
        "positive": "Position-space approach to hadronic light-by-light scattering in the\n  muon $g-2$ on the lattice: The anomalous magnetic moment of the muon currently exhibits a discrepancy of\nabout three standard deviations between the experimental value and recent\nStandard Model predictions. The theoretical uncertainty is dominated by the\nhadronic vacuum polarization and the hadronic light-by-light (HLbL) scattering\ncontributions, where the latter has so far only been fully evaluated using\ndifferent models. To pave the way for a lattice calculation of HLbL, we present\nan expression for the HLbL contribution to $g-2$ that involves a\nmultidimensional integral over a position-space QED kernel function in the\ncontinuum and a lattice QCD four-point correlator. We describe our\nsemi-analytic calculation of the kernel and test the approach by evaluating the\n$\\pi^0$-pole contribution in the continuum."
    },
    {
        "anchor": "Glueballs in Flatland: The pure gauge theory in 2+1 dimensions is explored, through both a\nphenomenological model and a lattice calculation. The Isgur-Paton model is\nextended to include a curvature term and various mixing mechanisms. The method\nof inferential statistics is used to extract the parameters of best fit and to\ncompare the likelihoods of the various models when compared to existing lattice\ndata. The conventional assignment of spin 0 to the pseudoscalar state is called\ninto question by the proximity of a spin 4 state in the model, which motivates\ncalculating the mass of the spin 4 state on the lattice. Novel lattice\noperators are constructed from a matrix of effective Greens functions which\nattempt to overcome the lattice rotational ambiguities. Correlation functions\nare presented for the channels with even J, and effective masses extracted. The\nresulting masses compare well with the extended Isgur-Paton model.",
        "positive": "A first study of the semi-leptonic decay of the $\u039b_b$ baryon: We present the preliminary results of the first Lattice study of the baryonic\nIsgur and Wise function obtained from the matrix element of the weak current\nbetween $\\Lambda$-baryon external states. Its dependence on the heavy and light\nquark masses is studied. Some result on the semi-leptonic decay\n$\\Lambda_b\\to\\Lambda_c +l\\nu$ are given."
    },
    {
        "anchor": "Topology (and axion's properties) from lattice QCD with a dynamical\n  charm: We present results on QCD with four dynamical flavors in the temperature\nrange $0.9 \\lesssim T/T_c \\lesssim 2$. We have performed lattice simulations\nwith Wilson fermions at maximal twist and measured the topological charge with\ngluonic and fermionic methods. The topological charge distribution is studied\nby means of its cumulants, which encode relevant properties of the QCD axion, a\nplausible Dark Matter candidate. The topological susceptibility measured with\nthe fermionic method exhibits a power-law decay for $T/T_c \\gtrsim 2$, with an\nexponent close to the one predicted by the Dilute Instanton Gas Approximation\n(DIGA). Close to $T_c$ the temperature dependent effective exponent approaches\nthe DIGA result from above, in agreement with recent analytic calculations.\nThese results constrain the axion window, once an assumption on the fraction of\naxions contributing to Dark Matter is made.",
        "positive": "Witten index from lattice simulation: I propose a method for measuring the Witten index using a lattice simulation.\nThe index is useful to discuss spontaneous breaking of supersymmetry. As a test\nof the method, I also report some numerical results for the supersymmetric\nquantum mechanics, for which the index is known."
    },
    {
        "anchor": "Excited hadrons on the lattice - State of the art and future challenges: We review the techniques of lattice QCD calculations for excited hadrons with\nlight quarks and outline the future challenges that are faced in calculations\nwith fully dynamical fermions.",
        "positive": "Monte Carlo simulation of $1+1$-dimensional $\u03c6^4$ quantum field\n  theory: We report results of a Monte Carlo simulation of the $\\phi^4$ quantum field\ntheory using multigrid simulation techniques and a refined discretization\nscheme. The resulting accuracy of our data allows for a significant test of an\nanalytical approximation based on a variational ansatz. While the variational\napproximation is well reproduced for a large range of parameters we find\nsignificant deviations for low temperatures and large couplings."
    },
    {
        "anchor": "Lattice formulation of three-dimensional ${\\cal N}=4$ gauge theory with\n  fundamental matter fields: We construct lattice action for three-dimensional ${\\cal N}=4$ supersymmetric\ngauge theory with matter fields in the fundamental representation.",
        "positive": "Statistical Models on Spherical Geometries: We use a one-dimensional random walk on $D$-dimensional hyper-spheres to\ndetermine the critical behavior of statistical systems in hyper-spherical\ngeometries. First, we demonstrate the properties of such a walk by studying the\nphase diagram of a percolation problem. We find a line of second and first\norder phase transitions separated by a tricritical point. Then, we analyze the\nadsorption-desorption transition for a polymer growing near the attractive\nboundary of a cylindrical cell membrane. We find that the fraction of adsorbed\nmonomers on the boundary vanishes exponentially when the adsorption energy\ndecreases towards its critical value."
    },
    {
        "anchor": "Perfect observables for the hierarchical non-linear $O(N)$-invariant\n  $\u03c3$-model: We compute moving eigenvalues and the eigenvectors of the linear\nrenormalization group transformation for observables along the renormalized\ntrajectory of the hierarchical non-linear $O(N)$-invariant $\\sigma$-model by\nmeans of perturbation theory in the running coupling constant. Moving\neigenvectors are defined as solutions to a Callan-Symanzik type equation.",
        "positive": "A Non-Abelian Variation on the Savvidy Vacuum of the Yang-Mills Gauge\n  Theory: As a prelude to a truly non-perturbative evaluation of the effective\npotential in terms of lattice QCD, the one loop effective potential for a\nnon-Abelian gauge configuration is calculated using the background field\nmethod. Through a non-trivial correlation between the space and color\norientations the new background field avoids the possible coordinate\nsingularity, ${\\rm Det}B_i^a=0$, observed recently by Ken Johnson and his\ncollaborators in their Schr\\\"{o}dinger functional study of the SU(2) Yang-Mills\ntheory. In addition, since our ansatz generates a constant color magnetic field\nthrough the commutator terms rather than derivative terms, many of the\ntechnical drawbacks the Savvidy ansatz suffers on a lattice can be avoided. Our\none loop study yields qualitatively the same result as that of Savvidy's."
    },
    {
        "anchor": "Topological charge density correlator in Lattice QCD with two flavours\n  of unimproved Wilson fermions: We study the two-point Topological Charge Density Correlator (TCDC) in\nlattice QCD with two degenerate flavours of unimproved Wilson fermions and\nWilson gauge action at two values of lattice spacings and different volumes,\nfor a range of quark masses. Configurations are generated with DDHMC algorithm\nand smoothed with HYP smearing. In order to shed light on the mechanisms\nleading to the observed suppression of topological susceptibility with respect\nto the decreasing quark mass and decreasing volume, in this work, we carry out\na detailed study of the two-point TCDC. We have shown that, (1) the TCDC is\nnegative beyond a positive core and radius of the core shrinks as lattice\nspacing decreases, (2) as the volume decreases, the magnitude of the contact\nterm and the radius of the positive core decrease and the magnitude of the\nnegative peak increases resulting in the suppression of the topological\nsusceptibility as the volume decreases, (3) the contact term and radius of the\npositive core decrease with decreasing quark mass at a given lattice spacing\nand the negative peak increases with decreasing quark mass resulting in the\nsuppression of the topological susceptibility with decreasing quark mass, (4)\nincreasing levels of smearing suppresses the contact term and the negative peak\nkeeping the susceptibility intact and (5) both the contact term and the\nnegative peak diverge in nonintegrable fashion as lattice spacing decreases. It\nis gratifying to note that observations similar to 1 and 5 have been made using\ntopological charge density operator based on chiral fermion. The observations 2\nand 3 may be confirmed more precisely by using formulations based on chiral\nfermions.",
        "positive": "Monte-Carlo-Simulations of Stochastic Differential Equations at the\n  Example of the Forced Burgers' Equation: We investigate the behaviour of stochastic differential equations, especially\nBurgers' eq., by means of Monte-Carlo-techniques."
    },
    {
        "anchor": "Chiral extrapolation of hyperon vector form factors: We present a new study of SU(3)-breaking corrections in hyperon vector form\nfactors relevant for the extraction of Vus. A lattice quenched simulation has\nbeen performed, showing that it is possible to reach the required precision to\nextract SU(3)-breaking corrections in the regime of simulated masses. In order\nto perform the chiral extrapolation we calculated the chiral corrections to the\nvector form factor in HBChPT. Besides the one-loop O(p^2) contribution, we\nincluded also the subleading O(p^3) and O(1/M_B) corrections that, due to the\nAdemollo-Gatto theorem, are free from the contamination of unknown low energy\nconstants. The results complete and correct previous calculations, and show\nthat subleading corrections cannot be neglected. We also studied decuplet\ncontributions within HBChPT and show that, in this case, the chiral expansion\nbreaks down, rising doubts on the consistency of the theory.",
        "positive": "Charmonium properties in hot quenched lattice QCD: We study the properties of charmonium states at finite temperature in\nquenched QCD on large and fine isotropic lattices. We perform a detailed\nanalysis of charmonium correlation and spectral functions both below and above\n$T_c$. Our analysis suggests that both S wave states ($J/\\psi$ and $\\eta_c$)\nand P wave states ($\\chi_{c0}$ and $\\chi_{c1}$) disappear already at about $1.5\nT_c$. The charm diffusion coefficient is estimated through the Kubo formula and\nfound to be compatible with zero below $T_c$ and approximately $1/\\pi T$ at\n$1.5 T_c\\lesssim T\\lesssim 3 T_c$."
    },
    {
        "anchor": "Quark Propagation in the Instantons of Lattice QCD: We quantitatively examine the extent to which instanton degress of freedom,\ncontained within standard Monte-carlo generated gauge-field configurations, can\nmaintain the characteristic features of the mass and renormalisation functions\nof the non-perturbative quark propagator. We use over-improved stout-link\nsmearing to isolate instanton effects on the lattice. Using a variety of\nmeasures, we illustrate how gauge fields consisting almost solely of\ninstanton-like objects are produced after only 50 sweeps of smearing. We find a\nfull vacuum, with a packing fraction more than three times larger than\nphenomenological models predict. We calculate the overlap quark propagator on\nthese smeared configurations, and find that even at high levels of smearing the\nmajority of the characteristic features of the propagator are reproduced. We\nthus conclude that instantons contained within standard Monte-carlo generated\ngauge-field configurations are the degrees of freedom responsible for the\ndynamical generation of mass observed in lattice QCD.",
        "positive": "Exploring the tension between nature and the Standard Model: the muon\n  g-2: Anomalous magnetic moment of the muon (muon g-2) is one of the most precisely\nmeasured quantities in particle physics. At the same time, it can be evaluated\nin the Standard Model with an unprecedented accuracy. The Muon g-2 experiment\nat Fermilab has started the major data collection and the aimed four-fold\nincrease in precision will shed light on the current discrepancy between the\ntheory prediction and the measured value. This renders a comparable improvement\nof the precision in the SM theory an essential ingredient in order to fully\nexploit the expected increase of precision in experimental results. For all\nthese reasons, the muon g-2 is considered to be a great testing ground for new\nphysics. Hadronic contributions are the dominant sources of uncertainty in the\ntheoretical prediction of the muon g-2. A reciprocal effort to a precise\ndetermination of the leading hadronic contribution to the muon g-2 using\nlattice gauge theories is a direct measurement of the hadronic contributions to\nthe running of the fine structure constant recently proposed by the MUonE\nexperiment. A hybrid strategy including both experimental and lattice data sets\nis expected to give an independent check of the dispersive results from\n$e^+e^-$ annihilation, which dominate the current world average."
    },
    {
        "anchor": "Charm spectroscopy on dynamical 2+1 flavor domain wall fermion lattices\n  with a relativistic heavy quark action: We present a preliminary calculation of the charmonium spectrum using the\ndynamical 2+1 flavor $24^3\\times 64$ domain wall fermion lattice configurations\ngenerated by the RBC and UKQCD collaborations. We use the relativistic heavy\nquark action with 3 parameters non-perturbatively determined by matching to\nexperimental quantities. Chiral extrapolation is done on four light sea quark\nmasses from 0.005 to 0.03, with $m_s=0.04$ and $m_{res}=0.003$. We can either\npredict meson masses assuming the lattice spacing is known from other methods,\nor calculate the lattice spacing using those quantities.",
        "positive": "Lattice QCD analysis for instantaneous interquark potential in\n  generalized Landau gauge: Using generalized Landau gauge, we study the continuous change of gluon\nproperties from the Landau gauge toward the Coulomb gauge in SU(3) lattice QCD.\nWe investigate \"instantaneous interquark potential\", which is defined by the\nspatial correlation of the temporal link-variable $U_4$ and is an interesting\ngauge-dependent concept. In the Coulomb gauge, the instantaneous potential is\nexpressed by the Coulomb plus linear potential, where the slope is, however,\n2-3 times as large as the physical string tension. In the Landau gauge, the\ninstantaneous potential has no linear part. We find that the linear part is\ncontinuously growing by varying gauge from the Landau gauge toward the Coulomb\ngauge. We also find that the instantaneous potential approximately reproduces\nthe physical interquark potential in a specific intermediate gauge,\n$\\lambda_C$-gauge. This $\\lambda_C$-gauge is expected to be a useful gauge for\nmodeling effective theories such as the quark potential model."
    },
    {
        "anchor": "Spanning of Topological sectors, charge and susceptibility with naive\n  Wilson fermions: We study the topological charge and the topological susceptibility in lattice\nQCD with two degenerate flavors of naive Wilson fermions at two values of\nlattice spacings and different volumes, for a range of quark masses.\nConfigurations are generated with DDHMC/HMC algorithms and smoothened with HYP\nsmearing. We present integrated autocorrelation time for both topological\ncharge and topological susceptibility at the two lattice spacing values\nstudied. The spanning of different topological sectors as a function of the\nhopping parameter kappa is presented. The expected chiral behaviour of the\ntopological susceptibility (including finite volume dependence) is observed.",
        "positive": "The sextet gauge model, light Higgs, and the dilaton: The frequently discussed strongly interacting gauge theory with a fermion\nflavor doublet in the two-index symmetric (sextet) representation of the SU(3)\ncolor gauge group is investigated \\cite{Fodor:2012ty}. The chiral condensate\nand the mass spectrum are consistent with chiral symmetry breaking at vanishing\nfermion mass. In contrast, sextet fermion mass deformations of spectral\nproperties are not consistent with leading conformal scaling behavior near the\ncritical surface of a conformal theory. A recent paper \\cite{DeGrand:2012yq}\nwhich could not resolve the conformal fixed point of the gauge coupling from\nthe slowly walking scenario of a very small nearly vanishing \\beta -function is\nnot in conflict with chiral symmetry breaking reported here. A light Higgs\nimpostor could emerge as the dilaton from spontaneous symmetry breaking of\nscale invariance or, without the dilaton mechanism, as a composite state."
    },
    {
        "anchor": "Probing the quark-gluon plasma with a new Fermionic correlator: We present the first measurement of a new correlation function of Fermion\nbilinears in finite temperature QCD with and without dynamical quarks in a\nquantum number channel in which non-trivial correlations are known to be\npresent for purely gluonic operators. We find that the Fermion correlator\nvanishes for $T \\ge 3T_c/2$, in agreement with the expectation for weakly\ninteracting quarks in a quark-gluon plasma.",
        "positive": "Supersymmetric Yang-Mills quantum mechanics in various dimensions: Supersymmetric Yang-Mills quantum mechanics (SYMQM) results from the\ndimensional reduction of the Yang-Mills field theory in $D$ space-time\ndimensions to a single point in the $D-1$ dimensional space. It can be also\nviewed as the effective quantum mechanics of zero momentum modes of the\noriginal theory. These systems were first considered in 80's as simple models\nwith supersymmetry. Independently, zero-volume field theories (especially pure\nYang-Mills) were employed as the starting point of the small volume expansion,\nwhich is an important theoretical tool complementary to early lattice\ncalculations. Later the models attracted a new wave of interest after the\nhypothesis of the equivalence, between the $D=10, SU(\\infty)$ SYMQM and a\nM-theory of D0 branes. In this talk some new results obtained for the D=4\nsystem with SU(2) gauge symmetry will be presented."
    },
    {
        "anchor": "Hybrid Monte Carlo Simulation of Graphene on the Hexagonal Lattice: We present a method for direct hybrid Monte Carlo simulation of graphene on\nthe hexagonal lattice. We compare the results of the simulation with exact\nresults for a unit hexagonal cell system, where the Hamiltonian can be solved\nanalytically.",
        "positive": "Direct Monte Carlo Measurement of the Surface Tension in Ising Models: I present a cluster Monte Carlo algorithm that gives direct access to the\ninterface free energy of Ising models. The basic idea is to simulate an\nensemble that consists of both configurations with periodic and with\nantiperiodic boundary conditions. A cluster algorithm is provided that\nefficently updates this joint ensemble. The interface tension is obtained from\nthe ratio of configurations with periodic and antiperiodic boundary conditions,\nrespectively. The method is tested for the 3-dimensional Ising model."
    },
    {
        "anchor": "Applications of Partially Quenched Chiral Perturbation Theory: Partially quenched theories are theories in which the valence- and sea-quark\nmasses are different. In this paper we calculate the nonanalytic one-loop\ncorrections of some physical quantities: the chiral condensate, weak decay\nconstants, Goldstone boson masses, B_K and the K+ to pi+ pi0 decay amplitude,\nusing partially quenched chiral perturbation theory. Our results for weak decay\nconstants and masses agree with, and generalize, results of previous work by\nSharpe. We compare B_K and the K+ decay amplitude with their real-world values\nin some examples. For the latter quantity, two other systematic effects that\nplague lattice computations, namely, finite-volume effects and unphysical\nvalues of the quark masses and pion external momenta are also considered. We\nfind that typical one-loop corrections can be substantial.",
        "positive": "Theory of Abelian Projection: Analytic methods for Abelian projection are developed. A number of results\nare obtained related to string tension measurements. It is proven that even\nwithout gauge fixing, abelian projection yields string tensions of the\nunderlying non-Abelian theory. Strong arguments are given for similar results\nin the case where gauge fixing is employed. The methods used emphasize that the\nprojected theory is derived from the underlying non-Abelian theory rather than\nvice versa. In general, the choice of subgroup used for projection is not very\nimportant, and need not be Abelian. While gauge fixing is shown to be in\nprinciple unnecessary for the success of Abelian projection, it is\ncomputationally advantageous for the same reasons that improved operators,\ne.g., the use of fat links, are advantageous in Wilson loop measurements. Two\nother issues, Casimir scaling and the conflict between projection and critical\nuniversality, are also discussed."
    },
    {
        "anchor": "Static quark anti-quark interactions at non-zero temperature from\n  lattice QCD: We study the interactions of a static quark antiquark pair at non-zero\ntemperature using realistic 2+1 flavor lattice QCD calculations. The study\nconsists of two parts: the first investigates the properties of Wilson line\ncorrelators in Coulomb gauge and compares to predictions of hard-thermal loop\nperturbation theory. As a second step we extract the spectral functions\nunderlying the correlators using four conceptually different methods: spectral\nfunction fits, a HTL inspired fit for the correlation function, Pad\\'e rational\napproximation and the Bayesian BR spectral reconstruction. We find that our\nhigh statistics Euclidean lattice data are amenable to different hypotheses for\nthe shapes of the spectral function and we compare the implications of each\nanalysis method for the existence and properties of a well defined ground state\nspectral peak.",
        "positive": "How to identify zero modes for improved staggered fermions: We present results of the eigenvalue spectrum for the staggered Dir\\\"ac\noperator obtained using a modified Lanczos algorithm. We identify zero modes\nand non-zero modes. We derive the chiral Ward identity derived from the\nconserved $U(1)_A$ symmetry, and check it numerically. This is the first step\ntoward construction of an improved method to identify zero modes reliably with\nstaggered fermions."
    },
    {
        "anchor": "Exact Pseudofermion Action for Monte Carlo Simulation of Domain-Wall\n  Fermion: We present an exact pseudofermion action for hybrid Monte Carlo simulation\n(HMC) of one-flavor domain-wall fermion (DWF), with the effective 4-dimensional\nDirac operator equal to the optimal rational approximation of the overlap-Dirac\noperator with kernel $ H = c H_w (1 + d \\gamma_5 H_w)^{-1} $, where $ c $ and $\nd $ are constants. Using this exact pseudofermion action, we perform HMC of\none-flavor QCD, and compare its characteristics with the widely used rational\nhybrid Monte Carlo algorithm (RHMC). Moreover, to demonstrate the practicality\nof the exact one-flavor algorithm (EOFA), we perform the first dynamical\nsimulation of the (1+1)-flavors QCD with DWF.",
        "positive": "The Thirring Model in 2+1$d$ with Optimised Domain Wall Fermions: After briefly reviewing the potential for the $N$-flavor Thirring model,\nformulated with reducible fermions in 2+1$d$, to exhibit a strongly-coupled\nUV-stable fixed point where U($2N$) symmetry is spontaneously broken by a\nfermion bilinear condensate, we present recent lattice studies using the Domain\nWall Fermion formulation. In particular, we focus on possible improved methods\nfor extracting the necessary $L_s\\to\\infty$ limit, where $L_s$ is the wall\nseparation, through a combination of partial quenching (ie. $L_s({\\rm\nvalence})>L_s({\\rm sea})$), replacing the Shamir kernel with the Wilson kernel\nin the definition of the overlap operator, and improved estimation of the\nsignum function using the Zolotarev approximation. Equation of state fits for\ncritical exponents on $12^3$ systems yield encouraging agreement between\ndistinct approaches, consistent with universal scaling, while contradicting\nearlier fits based on a naive extrapolation. The new results are also in\ntension with old results obtained with staggered fermions."
    },
    {
        "anchor": "Divergent chiral condensate in the quenched Schwinger model: We calculate numerically the eigenvalue distribution of the overlap Dirac\noperator in the quenched Schwinger model on a lattice. The distribution does\nnot fit any of the three universality classes of spontaneous chiral symmetry\nbreaking, and its strong volume dependence indicates that the chiral condensate\nin the quenched theory is an ill-defined and divergent quantity. When we\nreweight configurations with the Dirac determinant to study the theory with\nN_f=1, we obtain a distribution of eigenvalues that is well-behaved and\nconsistent with the theory of explicit symmetry breaking due to the anomaly.",
        "positive": "Lattice QCD at non-zero isospin chemical potential: Quantum chromodynamics (QCD) at non-zero isospin chemical potential is\nstudied in a canonical approach by analyzing systems of fixed isospin number\ndensity. To construct these systems, we develop a range of new algorithms for\nperforming the factorially large numbers of Wick contractions required in\nmulti-hadron systems. We then use these methods to study systems with the\nquantum numbers of up to 72 $\\pi^+$'s on three ensembles of gauge\nconfigurations with spatial extents $L\\sim$ 2.0, 2.5 and 3.0 fm, and light\nquark masses corresponding to a pion mass of {390 MeV}. The ground state\nenergies of these systems are extracted and the volume dependence of these\nenergies is utilized to determine the two- and three- body interactions amongst\n$\\pi^+$'s. The systems studied correspond to isospin densities of up to\n$\\rho_I\\sim 9\\ {\\rm fm}^{-3}$ and probe isospin chemical potentials, $\\mu_I$,\nin the range $m_\\pi\\ \\lsim \\mu_I\\ \\lsim 4.5\\ m_\\pi$, allowing us to investigate\naspects of the QCD phase diagram at low temperature and for varying isospin\nchemical potential. By studying the energy density of the system, we provide\nnumerical evidence for the conjectured transition of the system to a\nBose-Einstein condensed phase at $\\mu_I\\ \\gsim m_\\pi$."
    },
    {
        "anchor": "Partial breakdown of center symmetry in large-N QCD with adjoint Wilson\n  fermions: We study the one-loop potential of large-N QCD with adjoint Dirac fermions.\nSpace-time is a discretization of R^3 x S^1 where the compact direction\nconsists of a single lattice site. We use Wilson fermions with different values\nof the quark mass m and set the lattice spacings in the compact and non-compact\ndirections to be a_t and a_s respectively. Extending the results of JHEP\n0906:091,2009, we prove that if the ratio xi = a_s/a_t obeys 0<xi<2, then the\nminimum of the one-loop lattice potential for one or more Dirac flavors is Z_N\nsymmetric at the chiral point. For xi=0 our formulas reduce to those obtained\nin a continuum regularization of the R^3, and our proof holds in that case as\nwell. As we increase m from zero, we find a cascade of transitions where Z_N\nbreaks to Z_K. For very small masses, K ~ 1/(a_t m) >> 1, while for large\nmasses K ~ O(1). Despite certain UV sensitivities of the lattice one-loop\npotential, this phase structure is similar to the one obtained in the continuum\nworks of Kovtun-Unsal-Yaffe, Myers-Ogilvie, and Hollowood-Myers. We explain the\nphysical origin of the cascade of transitions and its relation to the embedding\nof space-time into color space.",
        "positive": "Chiral violations in domain-wall QCD from one-loop perturbation theory\n  at finite $N_s$: We present perturbative calculations made with domain-wall fermions which\npossess a finite number of points $N_s$ in the extra fifth dimension. We have\nderived the required propagator functions, investigated the one-loop properties\nof quark amplitudes at finite $N_s$ and evaluated three quantities that can\nprovide insights on chirality-breaking effects from the perturbative side.\n  First we have computed the residual mass for various choices of $N_s$ and of\nthe domain-wall height $M$. We have found that this radiatively induced mass\napproaches zero reasonably fast with the extent of the fifth dimension,\ndepending on $M$ and on a lesser extent on the coupling $g_0$. We have also\ncomputed the differences of the renormalization constants of the vector and\naxial-vector currents and of the scalar and pseudoscalar densities. Finally we\nhave calculated the chirally-forbidden mixing (which at finite $N_s$ is\nsuppressed only partially) of an operator which describes the lowest moment of\nthe $g_2$ structure function. In general we see that at $M=1.8$, where\nsimulations are usually performed, values of $N_s=20$ or larger would be\ndesirable in order for chiral violations to be negligible.\n  The quantities that we have studied turn out to lose gauge invariance when\n$N_s$ is not infinite. We have also found that anomalous dimensions of\noperators at finite $N_s$ generally depend on $N_s$ and $M$. In particular, the\nvector and axial-vector currents have in general a nonzero anomalous dimension\nat finite $N_s$."
    },
    {
        "anchor": "Hybrid Meson Spectrum from the FLIC action: The spectral properties of hybrid meson interpolating fields are\ninvestigated. The quantum numbers of the meson are carried by smeared-source\nfermion operators and highly-improved chromo-electric and -magnetic field\noperators composed with APE-smeared links. The effective masses of standard and\nhybrid operators indicate that the ground state meson is effectively isolated\nusing both standard and hybrid interpolating fields. Focus is placed on\ninterpolating fields in which the large spinor components of the quark and\nantiquark fields are merged. In particular, the effective mass of the exotic\n$1^{-+}$ meson is reported. Further, we report some values for excited mesonic\nstates using a variational process.",
        "positive": "Thermodynamics using Wilson and Staggered Quarks: Recent developements in QCD at finite temperature are reviewed. Particular\nemphasis is laid on results stemming from simulations which involve quarks."
    },
    {
        "anchor": "A perfect monopole action for SU(2) QCD: We found a quantum perfect lattice action in the 4-dimensional monopole\ncurrent theory which is known as an effective theory in the infrared region of\nQCD. The perfect monopole action is transformed exactly into a lattice action\nof a string model. When the monopole interactions are weak as in the case of\ninfrared SU(2) QCD, the string interactions are strong. The static potential\nand the string tension in this region can be estimated analytically by the use\nof the strong coupling expansion.",
        "positive": "Flavor-singlet spectrum in multi-flavor QCD: Studying SU(3) gauge theories with increasing number of light fermions is\nrelevant both for understanding the strong dynamics of QCD and for constructing\nstrongly interacting extensions of the Standard Model (e.g. UV completions of\ncomposite Higgs models). In order to contrast these many-flavors strongly\ninteracting theories with QCD, we study the flavor-singlet spectrum as an\ninteresting probe. In fact, some composite Higgs models require the Higgs boson\nto be the lightest flavor-singlet scalar in the spectrum of a strongly\ninteracting new sector with a well defined hierarchy with the rest of the\nstates. Moreover, introducing many light flavors at fixed number of colors can\ninfluence the dynamics of the lightest flavor-singlet pseudoscalar. We present\nthe on-going study of these flavor-singlet channels using multiple\ninterpolating operators on high-statistics ensembles generated by the LatKMI\ncollaboration and we compare results with available data obtained by the\nLattice Strong Dynamics collaboration. For the theory with 8 flavors, the two\ncollaborations have generated configurations that complement each others with\nthe aim to tackle the massless limit using the largest possible volumes."
    },
    {
        "anchor": "What lattice theorists can do for superstring/M-theory: The gauge/gravity duality provides us with nonperturbative formulation of\nsuperstring/M-theory. Although inputs from gauge theory side are crucial for\nanswering many deep questions associated with quantum gravitational aspects of\nsuperstring/M-theory, many of the important problems have evaded analytic\napproaches. For them, lattice gauge theory is the only hope at this moment. In\nthis review I give a list of such problems, putting emphasis on problems within\nreach in a five-year span, including both Euclidean and real-time simulations.",
        "positive": "Utility of geometry in lattice QCD simulations: We propose a way to improve the resolution of the spatial momentum and the\ntime interval for hadron propagators utilizing the lattice geometry. We\ndemonstrate the validity of the method presenting results for pseudoscalar\nmeson energies with and without finite momenta in a large-scale quenched QCD\nsimulation. The method should be useful especially for master-field\nsimulations."
    },
    {
        "anchor": "Three Dimensional Quantum Gravity Coupled to Ising Matter: We establish the phase diagram of three--dimensional quantum gravity coupled\nto Ising matter. We find that in the negative curvature phase of the quantum\ngravity there is no disordered phase for ferromagnetic Ising matter because the\ncoordination number of the sites diverges. In the positive curvature phase of\nthe quantum gravity there is evidence for two spin phases with a first order\ntransition between them.",
        "positive": "Three dimensional vacuum domains in four dimensional SU(2) gluodynamics: Performing lattice simulations of the four dimensional SU(2)gluodynamics we\nfind evidence for existence of three-dimensional domains whose total volume\nscales in physical units. Technically, the domains are defined in terms of the\nminimal density of negative links in Z(2) projection of gauge fields. The\nvolume can be viewed also as the minimal volume bound by the center vortices.\nWe argue that the three-dimensional domains are closely related to confinement."
    },
    {
        "anchor": "$\\mathcal{O}(a)$ improved quark mass renormalization for a\n  non-perturbative matching of HQET to three-flavor QCD: The use of Heavy Quark Effective Theory (HQET) on the lattice as an approach\nto B-physics phenomenology is based on a non-perturbative matching of HQET to\nQCD in finite volume. As a first step to apply the underlying strategy in the\nthree-flavor ($N_f = 2+1$) theory, we determine the renormalization constant\nand improvement coefficients relating the renormalized current and subtracted\nquark mass of (quenched) valence quarks in $\\mathcal{O}(a)$ improved $N_f=3$\nlattice QCD. We present our strategy and first results for the relevant\nparameter region towards weak couplings along a line of constant physics, which\ncorresponds to lattice resolutions $a\\leq 0.02\\,$fm and fixes the physical\nextent of the matching volume to $L\\approx 0.5\\,$fm.",
        "positive": "The Gluon Propagator in Momentum Space: We give preliminary numerical results for the gluon propagator evaluated both\nin coordinate and momentum space on a 16^3X40 quenched lattice at beta=6.0. Our\nfindings are compared with earlier results in the literature at zero momentum.\nIn addition, by considering nonzero momenta we attempt to extract the form of\nthe propagator and compare it to continuum predictions formulated by Gribov and\nothers. latex, file espcrc2.sty needed (appended at the end: search for\nespcrc2.sty)."
    },
    {
        "anchor": "$D \\rightarrow K, l \u03bd$ Semileptonic Decay Scalar Form Factor and\n  $|V_{cs}|$ from Lattice QCD: We present a new study of D semileptonic decays on the lattice which employs\nthe Highly Improved Staggered Quark (HISQ) action for both the charm and the\nlight valence quarks. We work with MILC unquenched $N_f = 2 + 1$ lattices and\ndetermine the scalar form factor $f_0(q^2)$ for $D \\rightarrow K, l \\nu$\nsemileptonic decays. The form factor is obtained from a scalar current matrix\nelement that does not require any operator matching. We develop a new approach\nto carrying out chiral/continuum extrapolations of $f_0(q^2)$. The method uses\nthe kinematic \"$z$\" variable instead of $q^2$ or the kaon energy $E_K$ and is\napplicable over the entire physical $q^2$ range. We find $f^{D \\rightarrow\nK}_0(0) \\equiv f^{D \\rightarrow K}_+(0) = 0.747(19)$ in the chiral plus\ncontinuum limit and hereby improve the theory error on this quantity by a\nfactor of $\\sim$4 compared to previous lattice determinations. Combining the\nnew theory result with recent experimental measurements of the product $f^{D\n\\rightarrow K}_+(0) * |V_{cs}| $ from BaBar and CLEO-c leads to the most\nprecise direct determination of the CKM matrix element $|V_{cs}| $ to date,\n$|V_{cs}| = 0.961(11)(24)$, where the first error comes from experiment and the\nsecond is the lattice QCD theory error. We calculate the ratio $f^{D\n\\rightarrow K}_+(0)/f_{D_s}$ and find $2.986 \\pm 0.087$ GeV$^{-1}$ and show\nthat this agrees with experiment.",
        "positive": "Exploring the Nucleon Structure from First Principles of QCD: Quantum Chromodynamics (QCD) is generally assumed to be the fundamental\ntheory underlying nuclear physics. In recent years there is progress towards\ninvestigating the nucleon structure from first principles of QCD. Although this\nstructure is best revealed in Deep Inelastic Scattering, a consistent analysis\nhas to be performed in a fully non-perturbative scheme. The only known method\nfor this purpose are lattice simulations. We first sketch the ideas of Monte\nCarlo simulations in lattice gauge theory. Then we comment in particular on the\nissues of chiral symmetry and operator mixing. Finally we present our results\nfor the Bjorken variable of a single quark, and for the second Nachtmann moment\nof the nucleon structure functions."
    },
    {
        "anchor": "Capillary Waves in Binder's Approach to the Interface Tension: In Binder's approach the reduced interface tension sigma of the Ising model\nin the broken phase is determined from the finite volume effects of the\npartition function Z(M) at fixed total magnetization M. For small |M| the\npartition function of a system of size L^d with periodic boundary conditions is\ndominated by configurations with two interfaces, such that Z(M) ~ exp(- 2 sigma\nL^{d-1}). Capillary wave fluctuations of the interfaces correct this result to\nZ(M) ~ exp(- 2 sigma L^{d-1}) with x = -1. The knowledge of the pre-exponential\nbehavior allows an improved fit of numerical data, and a determination of the\ninterface stiffness.",
        "positive": "Lattice computation of the Dirac eigenvalue density in the perturbative\n  regime of QCD: The eigenvalue spectrum $\\rho(\\lambda)$ of the Dirac operator is numerically\ncalculated in lattice QCD with 2+1 flavors of dynamical domain-wall fermions.\nIn the high-energy regime, the discretization effects become significant. We\nsubtract them at the leading order and then take the continuum limit with\nlattice data at three lattice spacings. Lattice results for the exponent\n$\\partial\\ln\\rho/\\partial\\ln\\lambda$ are matched to continuum perturbation\ntheory, which is known up to $O(\\alpha_s^4)$, to extract the strong coupling\nconstant $\\alpha_s$."
    },
    {
        "anchor": "Disconnected contributions to the spin of the nucleon: The spin decomposition of the proton is a long-standing topic of much\ninterest in hadronic physics. Lattice QCD has had much success in calculating\nthe connected contributions to the quark spin. However, complete calculations,\nwhich necessarily involve gluonic and strange-quark contributions, still\npresent some challenges. These \"disconnected\" contributions typically involve\nsmall signals hidden against large statistical backgrounds and rely on\ncomputationally intensive stochastic techniques. In this work we demonstrate\nhow a Feynman-Hellmann approach may be used to calculate such quantities, by\nmeasuring shifts in the proton energy arising from artificial modifications to\nthe QCD action. We find a statistically significant non-zero result for the\ndisconnected quark spin contribution to the proton of about -5% at a pion mass\nof 470 MeV.",
        "positive": "Scaling study of the relativistic corrections to the static potential: The relativistic corrections to the static potential, i.e. the O(1/m)\ncorrection, the O(1/m^2) spin-dependent and momentum-dependent corrections are\ninvestigated in SU(3) lattice gauge theory. These corrections are relevant\ningredients of an effective field theory for heavy quarkonium called potential\nnonrelativistic QCD. Utilizing the multilevel algorithm for the field strength\ncorrelator on the quark-antiquark source, these corrections are determined at\nthe distances ranged from 0.25 to 1.2 fm. A reasonable scaling behavior and\nlong-range nonperturbative contributions are observed."
    },
    {
        "anchor": "Lefschetz thimble structure in one-dimensional lattice Thirring model at\n  finite density: We investigate Lefschetz thimble structure of the complexified\npath-integration in the one-dimensional lattice massive Thirring model with\nfinite chemical potential. The lattice model is formulated with staggered\nfermions and a compact auxiliary vector boson (a link field), and the whole set\nof the critical points (the complex saddle points) are sorted out, where each\ncritical point turns out to be in a one-to-one correspondence with a singular\npoint of the effective action (or a zero point of the fermion determinant). For\na subset of critical point solutions in the uniform-field subspace, we examine\nthe upward and downward cycles and the Stokes phenomenon with varying the\nchemical potential, and we identify the intersection numbers to determine the\nthimbles contributing to the path-integration of the partition function. We\nshow that the original integration path becomes equivalent to a single\nLefschetz thimble at small and large chemical potentials, while in the\ncrossover region multi thimbles must contribute to the path integration.\nFinally, reducing the model to a uniform field space, we study the relative\nimportance of multiple thimble contributions and their behavior toward\ncontinuum and low-temperature limits quantitatively, and see how the rapid\ncrossover behavior is recovered by adding the multi thimble contributions at\nlow temperatures. Those findings will be useful for performing Monte-Carlo\nsimulations on the Lefschetz thimbles.",
        "positive": "Antiscreening of the Ampere force in QED and QCD plasmas: The static forces between electric charges and currents are modified at the\nloop level by the presence of a plasma. While electric charges are screened,\ncurrents are not. The effective coupling constant at long distances is enhanced\nin both cases as compared to the vacuum, and by different amounts, a clear sign\nthat Lorentz symmetry is broken. We investigate these effects quantitatively,\nfirst in a QED plasma and secondly using non-perturbative simulations of QCD\nwith two light degenerate flavors of quarks."
    },
    {
        "anchor": "Staggered fermions and their $O(a)$ improvements: Expanding upon the arguments of Sharpe, we explicitly implement the Symanzik\nimprovement program demonstrating the absence of order $a$ terms in the\nstaggered fermion action. We propose a general program to improve fermion\noperators to remove $O(a)$ corrections from their matrix elements, and\ndemonstrate this program for the examples of matrix elements of fermion\nbilinears and $B_K$. We also determine the additional operators which must be\nadded to improve the staggered fermion currents.",
        "positive": "Multi-quark energies in QCD: Four-quark potentials for $SU(2)$ are evaluated in the static limit with the\nquenched approximation -- using a lattice of $16^3\\times 32$ and $\\beta=2.4$.\nThe four quarks are restricted to the corners of rectangles with sides upto\nseven lattice spacings long. The results are analysed in terms of a strategy\nbased on interquark two-body potentials -- as advocated earlier by the authors.\nThis shows that a standard two-body approach overestimates the four-quark\nbinding energy by upto a factor of about three for the largest rectangles."
    },
    {
        "anchor": "Chiral observables and topology in hot QCD with two families of quarks: We present results on QCD with four dynamical flavors in the temperature\nrange $150$ MeV $\\lesssim T \\lesssim 500$ MeV. We have performed lattice\nsimulations with Wilson fermions at maximal twist and measured Polyakov loop,\nchiral condensate and disconnected susceptibility, on lattices with spacings as\nfine as 0.065 fm. For most observables spacing effects are below statistical\nerrors, which enables us to identify lattice results with continuum estimates.\nOur estimate of the pseudocritical temperature compares favorably with\ncontinuum results from staggered and domain wall fermions, confirming that a\ndynamical charm does not contribute in the transition region. From the high\ntemperature behaviour of the disconnected chiral susceptibility we infer the\ntopological susceptibility, which encodes relevant properties of the QCD axion,\na plausible Dark Matter candidate. The topological susceptibility thus measured\nexhibits a power-law decay for $T/T_c \\gtrsim 2$, with an exponent close to the\none predicted by the Dilute Instanton Gas Approximation (DIGA). Close to $T_c$\nthe temperature dependent effective exponent seems to approach the DIGA result\nfrom above, a behaviour which would support recent analytic calculations based\non an Instantons-dyons model. These results constrain the mass of a hypothetic\nQCD post-inflationary axion, once an assumption concerning the relative\ncontribution of axions to Dark Matter is made.",
        "positive": "A Lattice Computation of the Decay Constants of $B$ and $D$ Mesons: A lattice calculation of the pseudoscalar decay constant of heavy-light\nmesons is reported. Results are obtained (in the quenched approximation) from\nlattices at $\\beta=6.3$ through a procedure that interpolates between the\nstatic approximation of Eichten and the conventional (\"heavy\" Wilson fermion)\nmethod. The previously observed discrepancy between these two approaches has\nbeen resolved: we find the scaling quantity $f\\sqrt{M}$ to be significantly\nsmaller than previous calculations had indicated ({\\it e.g.} at $\\beta=6.0$);\nin addition, we discuss a modification which is required in normalizing the\nconventional amplitude to correct for large-$am$ lattice errors. This change\nguarantees that $f\\sqrt{M}$ will smoothly approach its value in the static\nlimit. From the numerical interpolation of the static and intermediate-mass\nresults, we find, in units of MeV, $f_B=187(10)\\pm34\\pm15$,\n$f_{B_s}=207(9)\\pm34\\pm22$, $f_D=208(9)\\pm35\\pm12$ and\n$f_{D_s}=230(7)\\pm30\\pm18$, where the first error is statistical and the second\ntwo are estimates of systematics due to 1) fitting and large-$am$ effects and\n2) scaling. In addition, using lattices at $\\beta=6.3$, $\\beta=6.0$ and\n$\\beta=5.7$ and extrapolating to the limit of zero lattice spacing, we have\ncomputed $f_K/f_\\pi = 1.08\\pm.03\\pm.08$ in the quenched approximation."
    },
    {
        "anchor": "Reconstruction of bottomonium spectral functions in thermal QCD using\n  Kernel Ridge Regression: We discuss results for bottomonium at nonzero temperature obtained using\nNRQCD on Fastsum Generation 2L ensembles, as part of the Fastsum\ncollaboration's programme to determine the spectrum of the bottomonium system\nas a function of temperature using a variety of approaches. Here we give an\nupdate on results for spectral functions obtained using Kernel Ridge\nRegression. We pay in particular attention to the generation of training data\nand introduce the notion of using lattice QCD ensembles to learn how to improve\nthe generation of training data. A practical implementation is given.",
        "positive": "Correlation functions with Karsten-Wilczek fermions: The Karsten-Wilczek action describes two chiral fermions but breaks the\nsymmetries under both charge conjugation ($ \\widehat{C}) $ and time reflection\n($ \\widehat{\\Theta} $) explicitly, though invariance under $ \\widehat{C\\Theta}\n$ and a mirror fermion symmetry $ \\widehat{T\\Theta} $ are maintained. These\nproceedings outline how the action's symmetries and the presence of the second\nfermion emerge in mesonic correlation functions.\n  The residual symmetries explain the non-observation of broken time-reflection\nsymmetry in a class of mesonic correlation functions. Time-reflection symmetry\nis enforced for correlation functions that are manifestly invariant under $\n\\widehat{C} $ or $ \\widehat{T} $. Due to contributions from the second fermion,\noscillating contributions arise in some mesonic correlation functions. A second\ncondition for non-perturbative tuning of the relevant counterterm is obtained\nfrom these oscillations. Both non-perturbative tuning conditions are\nindependent and agree within errors. Due to contributions from the second\nfermion, additional pseudoscalar states are observed in non-standard channels.\nMass splittings between these additional states and the Goldstone boson vanish\nas $ \\mathcal{O}(a^2) $."
    },
    {
        "anchor": "Lattice QCD at finite temperature and density: QCD at finite temperature and density is becoming increasingly important for\nvarious experimental programmes, ranging from heavy ion physics to\nastro-particle physics. The non-perturbative nature of non-abelian quantum\nfield theories at finite temperature leaves lattice QCD as the only tool by\nwhich we may hope to come to reliable predictions from first principles. This\nrequires careful extrapolations to the thermodynamic, chiral and continuum\nlimits in order to eliminate systematic effects introduced by the\ndiscretization procedure. After an introduction to lattice QCD at finite\ntemperature and density, its possibilities and current systematic limitations,\na review of present numerical results is given. In particular, plasma\nproperties such as the equation of state, screening masses, static quark free\nenergies and spectral functions are discussed, as well as the critical\ntemperature and the QCD phase structure at zero and finite density.",
        "positive": "Critical point in finite density lattice QCD by canonical approach: We propose a method to find the QCD critical point at finite density\ncalculating the canonical partition function ${\\cal Z}_{\\rm C} (T,N)$ by\nMonte-Carlo simulations of lattice QCD, and analyze data obtained by a\nsimulation with two-flavor p4-improved staggered quarks with pion mass $m_{\\pi}\n\\approx 770 {\\rm MeV}$. It is found that the shape of an effective potential\nchanges gradually as the temperature decreases and a first order phase\ntransition appears in the low temperature and high density region. This result\nstrongly suggests the existence of the critical point in the $(T, \\mu_q)$ phase\ndiagram."
    },
    {
        "anchor": "The Four-Fermi Model in Three Dimensions at Non-Zero Density and\n  Temperature: The Four Fermi model with discrete chiral symmetry is studied in three\ndimensions at non-zero chemical potential and temperature using the Hybrid\nMonte Carlo algorithm. The number of fermion flavors is chosen large $(N_f=12)$\nto compare with analytic results. A first order chiral symmetry restoring\ntransition is found at zero temperature with a critical chemical potential\n$\\mu_c$ in good agreement with the large $N_f$ calculations. The critical index\n$\\nu$ of the correlation length is measured in good agreement with analytic\ncalculations. The two dimensional phase diagram (chemical potential vs.\ntemperature) is mapped out quantitatively. Finite size effects on relatively\nsmall lattices and non-zero fermion mass effects are seen to smooth out the\nchiral transition dramatically.",
        "positive": "A Study of Hadron Deformation in Lattice QCD: We develop the formalism for the evaluation of density-density correlators in\nlattice QCD that includes techniques for the computation of the all-to-all\npropagators involved. A novel technique in this context is the implementation\nof the one-end trick in the meson sector. Density-density correlators provide a\ngauge invariant definition for the hadron wave function and yield information\non hadron deformation. We evaluate density-density correlators using two\ndegenerate flavors of dynamical Wilson fermions for the pion, the rho-meson,\nthe nucleon and the $\\Delta$. Using the one-end trick we obtain results that\nclearly show deformation of the rho-meson."
    },
    {
        "anchor": "Instanton dominance over $\u03b1_s$ at low momenta from lattice QCD\n  simulations at $N_f=0$, $N_f=2+1$ and $N_f=2+1+1$: We report on an instanton-based analysis of the gluon Green functions in the\nLandau gauge for low momenta; in particular we use lattice results for\n$\\alpha_s$ in the symmetric momentum subtraction scheme (${\\rm MOM}$) for\nlarge-volume lattice simulations. We have exploited quenched gauge field\nconfigurations, $N_f=0$, with both Wilson and tree-level Symanzik improved\nactions, and unquenched ones with $N_f=2+1$ and $N_f=2+1+1$ dynamical flavors\n(domain wall and twisted-mass fermions, respectively).\n  We show that the dominance of instanton correlations on the low-momenta gluon\nGreen functions can be applied to the determination of phenomenological\nparameters of the instanton liquid and, eventually, to a determination of the\nlattice spacing.\n  We furthermore apply the Gradient Flow to remove short-distance fluctuations.\nThe Gradient Flow gets rid of the QCD scale, $\\Lambda_{\\rm QCD}$, and reveals\nthat the instanton prediction extents to large momenta. For those gauge field\nconfigurations free of quantum fluctuations, the direct study of topological\ncharge density shows the appearance of large-scale lumps that can be identified\nas instantons, giving access to a direct study of the instanton density and\nsize distribution that is compatible with those extracted from the analysis of\nthe Green functions.",
        "positive": "Study of the a_0(980) on the lattice: We present lattice results for the a_0(980) state using a variational\napproach with a variety of creation operators: quark-antiquark, mesonic\nmolecule, diquark-antidiquark as well as two-meson type. Focus is put on recent\ntechnical advances, in particular the computation of singly disconnected\ndiagrams."
    },
    {
        "anchor": "Recent results of nucleon structure & matrix element calculations: A review of recent lattice calculations of nucleon structure and matrix\nelements of operators in nucleons is presented. It primarily covers\ndevelopments in the calculation of the matrix elements of the scalar, tensor,\npseudo-scalar, axial-vector and vector operators in the ground state of\nneutrons and protons in the isospin symmetric limit. Some preliminary\ncalculations of the electric dipole moment, the gravitational moments and\nstress-energy distribution, and the magnetic polarizability are briefly\ndescribed.",
        "positive": "A geometrical approach to N=2 super Yang-Mills theory on the two\n  dimensional lattice: We propose a discretization of two dimensional Euclidean Yang-Mills theories\nwith N=2 supersymmetry which preserves exactly both gauge invariance and an\nelement of supersymmetry. The approach starts from the twisted form of the\ncontinuum super Yang Mills action which we show may be written in terms of two\nreal Kahler-Dirac fields whose components transform into each other under the\ntwisted supersymmetry. Once the theory is written in this geometrical language\nit is straightforward to discretize by mapping the component tensor fields to\nappropriate geometrical structures in the lattice and by replacing the\ncontinuum exterior derivative and its adjoint by appropriate lattice covariant\ndifference operators. The lattice action is local and possesses a unique vacuum\nstate while the use of Kahler-Dirac fermions ensures the model does not exhibit\nspectrum doubling."
    },
    {
        "anchor": "The muon anomalous magnetic moment with staggered fermions: is the\n  lattice spacing small enough?: We extend our previous work on the light-quark connected part, $a_\\mu^{\\rm\nHVP,lqc}$, of the leading order hadronic-vacuum-polarization (HVP) contribution\nto the muon anomalous magnetic moment $a_\\mu$, using staggered fermions, in\nseveral directions. We have collected more statistics on ensembles with lattice\nspacings of $0.06$, $0.09$ and $0.12$ fm, and we added two new ensembles, both\nwith lattice spacing $0.15$ fm, but with different volumes. The increased\nstatistics allow us to reduce statistical errors on $a_\\mu^{\\rm HVP,lqc}$ and\nrelated window quantities significantly. We also calculate the current-current\ncorrelator from which $a_\\mu^{\\rm HVP,lqc}$ is obtained to\nnext-to-next-to-leading order (NNLO) in staggered chiral perturbation theory,\nso that we can correct lattice values for $a_\\mu^{\\rm HVP,lqc}$ to NNLO for\nfinite-volume, pion-mass mistuning and taste-breaking effects. We discuss the\napplicability of NNLO chiral perturbation theory to $a_\\mu^{\\rm HVP,lqc}$ and\nto the window quantities, emphasizing that it provides a systematic EFT\napproach to $a_\\mu^{\\rm HVP,lqc}$, but not to short- or intermediate-distance\nwindow quantities. This makes it difficult to assess systematic errors on the\nstandard intermediate-distance window quantity that is now widely considered in\nthe literature. In view of this, we investigate a longer-distance window, for\nwhich EFT methods should be more reliable. Our most important conclusion is\nthat, especially for staggered fermions, new high-statistics computations at\nlattice spacings smaller than $0.06$ fm are indispensable.",
        "positive": "From the colour glass condensate to filamentation: Systematics of\n  classical Yang-Mills theory: The non-equilibrium early time evolution of an ultra-relativistic heavy ion\ncollision is often described by classical lattice Yang-Mills theory, starting\nfrom the colour glass condensate (CGC) effective theory with an anisotropic\nenergy momentum tensor as initial condition. In this work we investigate the\nsystematics associated with such studies and their dependence on various model\nparameters (IR, UV cutoffs and the amplitude of quantum fluctuations) which are\nnot yet fixed by experiment. We perform calculations for SU(2) and SU(3), both\nin a static box and in an expanding geometry. Generally, the dependence on\nmodel parameters is found to be much larger than that on technical parameters\nlike the number of colours, boundary conditions or the lattice spacing. In a\nstatic box, all setups lead to isotropisation through chromo-Weibel\ninstabilities, which is illustrated by the accompanying filamentation of the\nenergy density. However, the associated time scale depends strongly on the\nmodel parameters and in all cases is longer than the phenomenologically\nexpected one. In the expanding system, no isotropisation is observed for any\nparameter choice. We show how investigations at fixed initial energy density\ncan be used to better constrain some of the model parameters."
    },
    {
        "anchor": "Compact lattice formulation of Cho-Faddeev-Niemi decomposition: gluon\n  mass generation and infrared Abelian dominance: This paper complements a new lattice formulation of SU(2) Yang-Mills theory\nwritten in terms of new variables in a compact form proposed in the previous\npaper. The new variables used in the formulation were once called the\nCho--Faddeev--Niemi or Cho--Faddeev--Niemi--Shabanov decomposition. Our\nformulation enables us to explain the infrared ``Abelian'' dominance, in\naddition to magnetic monopole dominance shown in the previous paper, in the\ngauge invariant way without relying on the specific gauge fixing called the\nmaximal Abelian gauge used in the conventional investigations. In this paper,\nespecially, we demonstrate by numerical simulations that gluon degrees of\nfreedom other than the ``Abelian'' part acquire the mass to be decoupled in the\nlow-energy region leading to the infrared Abelian dominance.",
        "positive": "Perfect Lattice Actions with and without Chiral Symmetry: We use perturbation theory to construct perfect lattice actions for fermions\nand gauge fields by blocking directly from the continuum. When one uses a\nrenormalization group transformation that preserves chiral symmetry the\nresulting lattice action for massless fermions is chirally symmetric but\nnonlocal. When the renormalization group transformation breaks chiral symmetry,\nthe lattice action becomes local but chiral symmetry is explicitly broken. In\nparticular, starting with a chiral gauge theory in the continuum one either\nobtains a lattice theory which is gauge invariant but nonlocal, or a local\ntheory with explicitly broken gauge invariance. In both cases the spectrum of\nthe lattice theory is identical with the one of the continuum and the anomaly\nis correctly reproduced. We also apply our techniques to vector-like theories.\nIn particular we propose a new renormalization group transformation for QCD and\nwe optimize its parameters for locality of the perfect action."
    },
    {
        "anchor": "Finite temperature SU(2) gauge theory: critical coupling and\n  universality class: We examine SU(2) gauge theory in 3+1 dimensions at finite temperature in the\nvicinity of critical point. For various lattice sizes in time direction\n($N_\\tau=1,2,4,8$) we extract high precision values of the inverse critical\ncoupling and critical values of the 4-th order cumulant of Polyakov loops\n(Binder cumulant). We check the universality class of the theory by comparing\nthe cumulant values to that of the 3D Ising model and find very good agreement.\n  The Polyakov loop correlators for the indicated lattices are also measured\nand the string tension values extracted. The high precision values of critical\ncoupling and string tension allow us to study the scaling of dimensionless\n$T_c/\\sqrt{\\sigma}$ ratio. The violation of scaling by <10% is observed as the\ncoupling is varied from weak to strong coupling regime.",
        "positive": "Equation of state in (2+1)-flavor QCD with gradient flow: The energy-momentum tensor and equation of state are studied in\nfinite-temperature (2+1)-flavor QCD with improved Wilson quarks using the\nmethod proposed by Makino and Suzuki based on the gradient flow. We find that\nthe results of the gradient flow are consistent with the previous results using\nthe $T$-integration method at $T \\mathrel{\\rlap{\\raise 0.511ex\n\\hbox{$<$}}{\\lower 0.511ex \\hbox{$\\sim$}}} 280$ MeV ($N_t\\mathrel{\\rlap{\\raise\n0.511ex \\hbox{$>$}}{\\lower 0.511ex \\hbox{$\\sim$}}}10$), while a disagreement is\nfound at $T \\mathrel{\\rlap{\\raise 0.511ex \\hbox{$>$}}{\\lower 0.511ex\n\\hbox{$\\sim$}}} 350$ MeV ($N_t \\mathrel{\\rlap{\\raise 0.511ex \\hbox{$<$}}{\\lower\n0.511ex \\hbox{$\\sim$}}} 8$) presumably due to the small-$N_t$ lattice artifact.\nWe also report on the results on the renormalized chiral condensate and its\ndisconnected susceptibility using the method of Hieda and Suzuki. The results\nshow a clear signal of the expected chiral restoration crossover even with\nWilson-type quarks which violate the chiral symmetry explicitly."
    },
    {
        "anchor": "On the weak N-dependence of SO(N) and SU(N) gauge theories in 2+1\n  dimensions: We consider (continuum) mass ratios of the lightest `glueballs' as a function\nof N for SO(N) and SU(N) lattice gauge theories in D=2+1. We observe that the\nleading large N correction is usually sufficient to describe the N-dependence\nof SO(N.geq.3) and SU(N.geq.2), within the errors of the numerical calculation.\nJust as interesting is the fact that the coefficient of this correction almost\ninvariably turns out to be anomalously small, for both SO(N) and SU(N). We\npoint out that this can follow naturally from the strong constraints that one\nnaively expects from the Lie algebra equivalence between certain SO(N) and\nSU(N') theories and the equivalence of SO(infinity) and SU(infinity). The same\nargument for a weak N-dependence can in principle apply to SU(N) and SO(N)\ngauge theories in D=3+1.",
        "positive": "A Class of Saddle-point Configurations in three-dimensional SU(2)\n  Lattice Gauge Theory: We discuss a class of saddle-point configurations in SU(2) lattice gauge\ntheory in three Euclidean dimensions. These configurations are smooth on the\nscale of the lattice and have an action density exhibiting localized peaks, as\nhas been seen in cooled and extremized Monte Carlo generated lattices. Large\nWilson loops centered on the action peaks show a unit of Z(2) flux. We discuss\nthe generation of these configurations and measurements of the Creutz ratios on\nthem."
    },
    {
        "anchor": "Pseudo scalar meson masses in Wilson Chiral Perturbation Theory for 2+1\n  flavors: We consider 2+1 flavor Wilson Chiral Perturbation Theory including the\nlattice spacing contributions of O($a^{2}$). We adopt a power counting\nappropriate for the unquenched lattice simulations carried out by the\nCP-PACS/JLQCD collaboration and compute the pseudo scalar meson masses to one\nloop. These expression are required to perform the chiral extrapolation of the\nCP-PACS/JLQCD lattice data.",
        "positive": "Scaling study of dynamical smeared-link clover fermions: We present a framework for phenomenological lattice QCD calculations which\nmakes use of a tree level Symanzink improved action for gluons and stout-link\nWilson fermions. We give details of our efficient HMC/RHMC algorithm and\npresent a scaling study of the low-lying N_f=3 baryon spectrum. We find a\nscaling region that extends to a~<0.16fm and conclude that our action and\nalgorithm are suitable for large scale phenomenological investigations of\nN_f=2+1 QCD. We expect this conclusion to hold for other comparable actions."
    },
    {
        "anchor": "Step scaling and the Yang-Mills gradient flow: The use of the Yang-Mills gradient flow in step-scaling studies of lattice\nQCD is expected to lead to results of unprecedented precision. Step scaling is\nusually based on the Schr\\\"odinger functional, where time ranges over an\ninterval [0,T] and all fields satisfy Dirichlet boundary conditions at time 0\nand T. In these calculations, potentially important sources of systematic\nerrors are boundary lattice effects and the infamous topology-freezing problem.\nThe latter is here shown to be absent if Neumann instead of Dirichlet boundary\nconditions are imposed on the gauge field at time 0. Moreover, the expectation\nvalues of gauge-invariant local fields at positive flow time (and of other well\nlocalized observables) that reside in the center of the space-time volume are\nfound to be largely insensitive to the boundary lattice effects.",
        "positive": "Centre Vortices in SU(3): We investigate the effectiveness of using smearing as a means to generate a\npreconditioning transformation for gauge fields prior to fixing to Maximal\nCentre Gauge. This still leaves the gauge-fixed field in the original gauge\norbit. As expected, we find that this preconditioning leads to higher maxima of\nthe gauge-fixing condition, resulting in lower numbers of P-vortices. We also\nfind that removing vortices appears to give a loss of confinement for all cases\nbut that the string tension as measured from vortex-only configurations drops\nfrom about 65% to as low as 26% when using the preconditioning method."
    },
    {
        "anchor": "Quark Mass Renormalization on the Lattice with Staggered Fermions: The QCD light quark mass renormalized at a 1 GeV scale in the $ \\overline{MS}\n$ scheme is obtained from the numerical results of the lattice QCD simulation\nwith staggered fermions. The primary emphasis is given to the connection\nbetween the lattice and continuum parameters. The results are compared with\nthose from the QCD sum rule.",
        "positive": "The pion and kaon $\\langle x^3 \\rangle$ from lattice QCD and PDF\n  reconstruction from Mellin moments: We present a calculation of the pion and kaon Mellin moment $\\langle x^3\n\\rangle$ extracted directly in lattice QCD using a three-derivative local\noperator. We use one ensemble of gauge configurations with two degenerate\nlight, a strange and a charm quark ($N_f=2+1+1$) of maximally twisted mass\nfermions with clover improvement. The ensemble reproduces a pion mass $\\sim260$\nMeV, and a kaon mass $\\sim530$ MeV. Excited-states contamination is evaluated\nusing four values of the source-sink time separation within the range of\n$1.12-1.67$ fm. We use an operator that is free of mixing, and apply a\nmultiplicative renormalization function calculated non-perturbatively. Our\nresults are converted to the $\\overline{\\rm MS}$ scheme and evolved at a scale\nof 2 GeV, using three-loop expressions in perturbation theory. The final values\nare $\\langle x^3 \\rangle_\\pi^{u^+}=0.024(18)_{\\rm stat}(2)_{\\rm syst}$,\n$\\langle x^3 \\rangle_K^{u^+}=0.035(6)_{\\rm stat}(3)_{\\rm syst}$, and $\\langle\nx^3 \\rangle_K^{s^+}=0.075(5)_{\\rm stat}(1)_{\\rm syst}$, where the systematic\nerror is the uncertainty due to excited state contamination.\n  We combine $\\langle x^3 \\rangle$ with the two lower moments to obtain the\nratios $\\langle x^3 \\rangle/\\langle x \\rangle$ and $\\langle x^3 \\rangle/\\langle\nx^2 \\rangle$, as well as ratios between the pion and kaon moments. In addition,\nwe reconstruct the $x$-dependence of the pion and kaon PDFs via 2- and\n3-parameter fits to our results. We find that the reconstruction is feasible\nand that our lattice data favor a large $x$-dependence that falls as $(1-x)^2$\nfor both the pion and kaon PDFs. We integrate the reconstructed PDFs to extract\nthe higher moments with $4\\leq n\\leq 6$. Finally, we compare the pion and kaon\nPDFs, as well as the ratios of their moments, to address the effect of SU(3)\nflavor symmetry breaking."
    },
    {
        "anchor": "GPU-Acceleration of Tensor Renormalization with PyTorch using CUDA: We show that numerical computations based on tensor renormalization group\n(TRG) methods can be significantly accelerated with PyTorch on graphics\nprocessing units (GPUs) by leveraging NVIDIA's Compute Unified Device\nArchitecture (CUDA). We find improvement in the runtime and its scaling with\nbond dimension for two-dimensional systems. Our results establish that the\nutilization of GPU resources is essential for future precision computations\nwith TRG.",
        "positive": "Screening correlators with chiral Fermions: We study screening correlators of quark-antiquark composites at T=2T_c, where\nT_c is the QCD phase transition temperature, using overlap quarks in the\nquenched approximation of lattice QCD. As the lattice spacing is changed from\n1/4T to a=1/6T and 1/8T, we find that screening correlators change little, in\ncontrast with the situation for other types of lattice fermions. All\ncorrelators are close to the ideal gas prediction at small separations. The\nlong distance falloff is clearly exponential, showing that a parametrization by\na single screening length is possible at distances z > 1/T. The correlator\ncorresponding to the thermal vector is close to the ideal gas value at all\ndistances, whereas that for the thermal scalar deviates at large distances.\nThis is examined through the screening lengths and momentum space correlators.\nThere is strong evidence that the screening transfer matrix does not have\nreflection positivity."
    },
    {
        "anchor": "Additional Strange Hadrons from QCD Thermodynamics and Strangeness\n  Freeze-out in Heavy Ion Collisions: We compare lattice QCD results for appropriate combinations of net\nstrangeness fluctuations and their correlations with net baryon number\nfluctuations with predictions from two hadron resonance gas (HRG) models having\ndifferent strange hadron content. The conventionally used HRG model based on\nexperimentally established strange hadrons fails to describe the lattice QCD\nresults in the hadronic phase close to the QCD crossover. Supplementing the\nconventional HRG with additional, experimentally uncharted strange hadrons\npredicted by quark model calculations and observed in lattice QCD spectrum\ncalculations leads to good descriptions of strange hadron thermodynamics below\nthe QCD crossover. We show that the thermodynamic presence of these additional\nstates gets imprinted in the yields of the ground-state strange hadrons leading\nto a systematic 5--8 MeV decrease of the chemical freeze-out temperatures of\nground-state strange baryons.",
        "positive": "Finite Volume Corrections to the Electromagnetic Mass of Composite\n  Particles: The long-range electromagnetic interaction presents a challenge for numerical\ncomputations in QCD + QED. In addition to power-law finite volume effects, the\nstandard lattice gauge theory approach introduces non-locality through removal\nof photon zero-momentum modes. The resulting finite volume effects must be\nquantitatively understood; and, to this end, non-relativistic effective field\ntheories are an efficient tool, especially in the case of composite particles.\nRecently an oddity related to non-locality of the standard lattice approach was\nuncovered by the Budapest-Marseille-Wuppertal collaboration. Explicit\ncontributions from antiparticles appear to be required so that finite volume\nQED results for a point-like fermion can be reproduced in the effective field\ntheory description. We provide transparency for this argument by considering\npoint-like scalars and spinors in finite volume QED using the method of\nregions. For the more germane case of composite particles, we determine that\nantiparticle modes contribute to the finite-volume electromagnetic mass of\ncomposite spinors through terms proportional to the squares of time-like form\nfactors evaluated at threshold. We extend existing finite volume calculations\nto one order higher, which is particularly relevant for the electromagnetic\nmass of light nuclei. Additionally, we verify that the analogous finite volume\ncontributions to the nucleon mass in chiral perturbation theory vanish in\naccordance with locality."
    },
    {
        "anchor": "Teaching to extract spectral densities from lattice correlators to a\n  broad audience of learning-machines: We present a new supervised deep-learning approach to the problem of the\nextraction of smeared spectral densities from Euclidean lattice correlators. A\ndistinctive feature of our method is a model-independent training strategy that\nwe implement by parametrizing the training sets over a functional space spanned\nby Chebyshev polynomials. The other distinctive feature is a reliable estimate\nof the systematic uncertainties that we achieve by introducing several\nensembles of machines, the broad audience of the title. By training an ensemble\nof machines with the same number of neurons over training sets of fixed\ndimensions and complexity, we manage to provide a reliable estimate of the\nsystematic errors by studying numerically the asymptotic limits of infinitely\nlarge networks and training sets. The method has been validated on a very large\nset of random mock data and also in the case of lattice QCD data. We extracted\nthe strange-strange connected contribution to the smeared $R$-ratio from a\nlattice QCD correlator produced by the ETM Collaboration and compared the\nresults of the new method with the ones previously obtained with the HLT method\nby finding a remarkably good agreement between the two totally unrelated\napproaches.",
        "positive": "A Lattice Study of the Glueball Spectrum: Glueball spectrum is studied using an improved gluonic action on asymmetric\nlattices in the pure SU(3) gauge theory. The smallest spatial lattice spacing\nis about $0.08fm$ which makes the extrapolation to the continuum limit more\nreliable. In particular, attention is paid to the scalar glueball mass which is\nknown to have problems in the extrapolation. Converting our lattice results to\nphysical units using the scale set by the static quark potential, we obtain the\nfollowing results for the glueball masses: $M_G(0^{++})=1730(90)MeV$ for the\nscalar glueball mass and $M_G(2^{++})=2400(95)MeV$ for the tensor glueball."
    },
    {
        "anchor": "$1/N$ Expansion of Two-Dimensional Models in the Scaling Region: The main technical and conceptual features of the lattice $1/N$ expansion in\nthe scaling region are discussed in the context of a two-parameter\ntwo-dimensional spin model interpolating between $CP^{N-1}$ and $O(2N)$\n$\\sigma$ models, with standard and improved lattice actions. We show how to\nperform the asymptotic expansion of effective propagators for small values of\nthe mass gap and how to employ this result in the evaluation of physical\nquantities in the scaling regime. The lattice renormalization group $\\beta$\nfunction is constructed explicitly and exactly to $O({1/N})$.",
        "positive": "Tuning the hopping parameter in the Oktay-Kronfeld action for charm and\n  bottom quarks on a MILC HISQ ensemble: The first step in the calculation of semi-leptonic form factors in the decay\nof heavy mesons is the tuning of the hopping parameter $\\kappa$ for the charm\nand bottom quark masses. Results for the Oktay-Kronfeld (OK) action are\npresented for one $N_f=2+1+1$ HISQ ensemble generated by the MILC collaboration\nat $a\\approx 0.12\\,\\mathrm{fm}$ and $M_\\pi\\approx 310$ MeV. Estimates of\nhyperfine splitting of heavy-light and heavy-heavy mesons are presented and the\ninconsistency parameter is evaluated."
    },
    {
        "anchor": "Topologically non-trivial field configurations - interplay of vortices\n  and Dirac eigenmodes: Gluon field configurations with non-trivial topology like instantons,\nmagnetic monopoles and center vortices play a crucial role in QCD and, in\nparticular, for the spontaneous breaking of chiral symmetry. Moreover, center\nvortices are strongly correlated with confinement. We present evidence, that\nthere is a deep connection between the topology of gauge fields and center\nvortices. We use the chirally improved lattice Dirac operator to compute\neigenvectors and eigenvalues of various lattice gauge field configurations.\nRemoving vortices from thermalized configurations also removes the topological\ncontent of the gauge field. As a consistency check, we apply random changes to\nthe raw configurations.",
        "positive": "The static three-quark SU(3) and four-quark SU(4) potentials: We present results on the static three- and four-quark potentials in SU(3)\nand SU(4) respectively within quenched lattice QCD. We use an analytic\nmulti-hit procedure for the time links and a variational approach to determine\nthe ground state. The three- and four-quark potentials extracted are consistent\nwith a sum of two-body potentials, possibly with a weak many-body component.\nThe results give support to the $\\Delta$ ansatz for the baryonic area law."
    },
    {
        "anchor": "Lattice Study on quantum-mechanical dynamics of two-color QCD with six\n  light flavors: We investigate the chiral properties of SU(2) gauge theory with six flavors,\ni.e. six light Dirac fermions in the fundamental representations by lattice\nsimulation, and point out that the spontaneous breakdown of chiral symmetry\ndoes not occur in this system. The quark mass dependence of the mesonic\nspectrum provides an evidence for such a possibility. The decay constant tends\nto be increased by the finite size effect, which is opposite to the behavior\npredicted by chiral perturbation theory and indicates that the long distance\ndynamics in the six-flavor theory could be different from the theory with\nchiral symmetry breaking. The subtracted chiral condensate, whose utility is\ndemonstrated by the simulation of two-flavor theory, is shown to vanish in the\nchiral limit within the precision of available data.",
        "positive": "On the Determination of Elastic and Inelastic Nuclear Observables from\n  Lattice QCD: One of the overarching goals of nuclear physics is to rigorously compute\nproperties of hadronic systems directly from the fundamental theory of the\nstrong interaction, Quantum Chromodynamics (QCD). Currently, lattice QCD (LQCD)\nprovides the only reliable option for performing calculations of low-energy\nhadronic observables. LQCD calculations are necessarily performed in a finite\nEuclidean spacetime. As a result, it is necessary to construct formalism that\nmaps the finite-volume observables determined via LQCD to the infinite-volume\nquantities of interest. This methodology is commonly referred to as the Luscher\nmethod, as it was Martin Luscher who first developed such formalism for scalar\nbosons with zero total momentum below inelastic thresholds. In this work, we\nreview recent progress on the generalization of this formalism. We present a\ndetailed derivation of the extension of Luscher's seminal work for\nmulti-channel two-body scalar systems, two-nucleon non-relativistic systems,\nand three-body non-relativistic scalar systems. For all of these scenarios we\nallow for the total momenta of the systems of interest to be nonzero. We also\npresent steps towards being able to study weak processes involving two-nucleon\nsystems, in particular we show how to determine the transition amplitude for\nproton-proton fusion (pp->e^+ + nu_e) directly from LQCD."
    },
    {
        "anchor": "Perturbative Corrections for Staggered Fermion Bilinears: We calculate the perturbative corrections to fermion bilinears that are used\nin numerical simulations when extracting weak matrix elements using staggered\nfermions. This extends previous calculations of Golterman and Smit, and Daniel\nand Sheard. In particular, we calculate the corrections for non-local bilinears\ndefined in Landau gauge with gauge links excluded. We do this for the simplest\noperators, i.e. those defined on a $2^4$ hypercube, and for tree level improved\noperators which live on $4^4$ hypercubes. We also consider gauge invariant\noperators in which the ``tadpole'' contributions are suppressed by projecting\nthe sums of products of gauge links back in to the gauge group. In all cases,\nwe find that the variation in the size of the perturbative corrections is\nsmaller than those with the gauge invariant unimproved operators. This is most\nstrikingly true for the smeared operators. We investigate the efficacy of the\nmean-field method of Lepage and Mackenzie at summing up tadpole contributions.\nIn a companion paper we apply these results to four-fermion operators.",
        "positive": "Determination of the mass anomalous dimension for $N_f=12$ and $N_f=9$\n  SU($3$) gauge theories: We show the numerical simulation result for the mass anomalous dimension of\nthe SU($3$) gauge theory coupled to $N_f = 12$ fundamental fermions. We use two\nindependent methods, namely the step scaling method and the hyperscaling method\nof the Dirac mode number, to determine the anomalous dimension in the vicinity\nof the infrared fixed point of the theory. We show the continuum extrapolations\nkeeping the renormalized coupling constant as a reference in both analyses.\n  Furthermore, some recent works seems to suggest the lower boundary of the\nconformal window of the SU($3$) gauge theory exists between $N_f=8$ and $10$.\nWe also briefly report our new project, in which the numerical simulation of\nthe SU($3$) gauge theory coupled to $N_f=9$ fundamental fermions has been\nperformed."
    },
    {
        "anchor": "Instanton Content of the SU(3) Vacuum: We study the topological content of the SU(3) vacuum using a method based on\nRG mapping developed for SU(2) gauge theory earlier. RG mapping, in which a\nseries of APE-smearing steps is done while tracking the observables, reduces\nthe short range fluctuations in the gauge fields while preserving the long\nstructure. This allows us to study the instanton size distribution and\ntopological susceptibility for SU(3) gauge theory. We arrive at a value for the\ntopological susceptibility ${\\chi}^{1/4}$, of 203(5) MeV. The size distribution\npeaks at $\\rho = 0.3fm$, and is in good agreement with the prediction of the\ninstanton liquid models.",
        "positive": "Improving cosmic string network simulations: In real-time lattice simulations of cosmic strings in the Abelian Higgs\nmodel, the broken translational invariance introduces lattice artefacts;\nrelativistic strings therefore decelerate and radiate. We introduce two\ndifferent methods to construct a moving string on the lattice, and study in\ndetail the lattice effects on moving strings. We find that there are two types\nof lattice artefact: there is an effective maximum speed with which a moving\nstring can be placed on the lattice, and a moving string also slows down, with\nthe deceleration approximately proportional to the exponential of the velocity.\nTo mitigate this, we introduce and study an improved discretisation, based on\nthe tree-level L\\\"{u}scher-Weisz action, which is found to reduce the\ndeceleration by an order of magnitude, and to increase the string speed limit\nby an amount equivalent to halving the lattice spacing. The improved algorithm\nis expected to be very useful for 3D simulations of cosmic strings in the early\nuniverse, where one wishes to simulate as large a volume as possible."
    },
    {
        "anchor": "Bottomonia correlators and spectral functions at zero and finite\n  temperature: We present preliminary studies of bottomonia spectral functions at zero and\nfinite temperature using quenched anisotropic lattices. The heavy quark is\ntreated within Fermilab approach. We find no modification of the $\\eta_b$ and\n$\\Upsilon$ states up to temperatures $2.3T_c$ while our study suggest\ndissolution of $\\chi_b$ state at $1.15T_c$.",
        "positive": "Hadronic vacuum polarization with C* boundary conditions: We present a progress report on the calculation of the connected hadronic\ncontribution to the muon g-2 with C* boundary conditions. For that purpose we\nuse a QCD gauge ensemble with 3+1 flavors and two QCD+QED gauge ensembles with\n1+2+1 flavors of dynamical quarks generated by the RC* collaboration. We detail\nthe calculation of the vector mass and elaborate on both statistical and\nsystematic errors."
    },
    {
        "anchor": "Spectrum of SU(2) lattice gauge theory with two adjoint Dirac flavours: An SU(2) gauge theory with two fermions transforming under the adjoint\nrepresentation of the gauge group may appear conformal or almost conformal in\nthe infrared. We use lattice simulations to study the spectrum of this theory\nand present results on the masses of several gauge singlet states as a function\nof the physical quark mass determined through the axial Ward identity and find\nindications of a change from chiral symmetry breaking to a phase consistent\nwith conformal behaviour at beta_L ~ 2. However, the measurement of the\nspectrum is not alone sufficient to decisively confirm the existence of\nconformal fixed point in this theory as we show by comparing to similar\nmeasurements with fundamental fermions. Based on the results we sketch a\npossible phase diagram of this lattice theory and discuss the applicability and\nimportance of these results for the future measurement of the evolution of the\ncoupling constant.",
        "positive": "Hypercubic effects in semileptonic decays of heavy mesons, toward $B \\to\n  \u03c0\\ell \u03bd$, with $N_f=2+1+1$ Twisted fermions: We present a preliminary study toward a lattice determination of the vector\nand scalar form factors of the $B \\to \\pi \\ell \\nu$ semileptonic decays. We\ncompute the form factors relative to the transition between heavy-light\npseudoscalar mesons, with masses above the physical D-mass, and the pion. We\nsimulate heavy-quark masses in the range $m_c^{phys} < m_h < 2m_c^{phys}$.\nLorentz symmetry breaking due to hypercubic effects is clearly observed in the\ndata, and included in the decomposition of the current matrix elements in terms\nof additional form factors. We discuss the size of this breaking as the\nparent-meson mass increases. Our analysis is based on the gauge configurations\nproduced by the European Twisted Mass Collaboration with $N_f = 2 + 1 + 1$\nflavors of dynamical quarks at three different values of the lattice spacing\nand with pion masses as small as $210$ MeV."
    },
    {
        "anchor": "K->pi form factors with reduced model dependence: Using partially twisted boundary conditions we compute the K->pi\nsemi-leptonic form factors in the range of momentum transfers 0 <~ q^2 <=\nq^2_{max}=(mK-mpi)^2 in lattice QCD with N_f=2+1 dynamical flavours. In this\nway we are able to determine f+(0) without any interpolation in the momentum\ntransfer, thus eliminating one source of systematic error. This study confirms\nour earlier phenomenological ansatz for the strange quark mass dependence of\nthe scalar form factor. We identify and estimate potentially significant NNLO\neffects in the chiral expansion that guides the extrapolation of the data to\nthe physical point. Our main result is f+(0) = 0.9599(34)(^{+31}_{-43})(14)$,\nwhere the first error is statistical, the second error is due to the\nuncertainties in the chiral extrapolation of the lattice data and the last\nerror is an estimate of potential discretisation effects.",
        "positive": "HVP contributions to the muon ($g - 2$) including QED corrections with\n  twisted-mass fermions: We present a lattice calculation of the Hadronic Vacuum Polarization (HVP)\ncontribution of the strange and charm quarks to the anomalous magnetic moment\nof the muon including leading-order electromagnetic (e.m.) corrections. We\nemploy the gauge configurations generated by the European Twisted Mass\nCollaboration (ETMC) with $N_f = 2+1+1$ dynamical quarks at three values of the\nlattice spacing ($a \\simeq 0.062, 0.082, 0.089$ fm) with pion masses in the\nrange $M_\\pi \\simeq 210 - 450$ MeV. The strange and charm quark masses are\ntuned at their physical values. Neglecting disconnected diagrams and after the\nextrapolations to the physical pion mass and to the continuum limit we obtain:\n$a_\\mu^s(\\alpha_{em}^2) = (53.1 \\pm 2.5) \\cdot 10^{-10}$,\n$a_\\mu^s(\\alpha_{em}^3) = (-0.018 \\pm 0.011) \\cdot 10^{-10}$ and\n$a_\\mu^c(\\alpha_{em}^2) = (14.75 \\pm 0.56) \\cdot 10^{-10}$,\n$a_\\mu^c(\\alpha_{em}^3) = (-0.030 \\pm 0.013) \\cdot 10^{-10}$ for the strange\nand charm contributions, respectively."
    },
    {
        "anchor": "Exact Chiral Symmetry on the Lattice: Developments during the last eight years have refuted the folklore that\nchiral symmetries cannot be preserved on the lattice. The mechanism that\npermits chiral symmetry to coexist with the lattice is quite general and may\nwork in Nature as well. The reconciliation between chiral symmetry and the\nlattice is likely to revolutionize the field of numerical QCD.",
        "positive": "Dimensional Reduction and Screening Masses in Pure Gauge Theories at\n  Finite Temperature: We studied screening masses in the equilibrium thermodynamics of SU(2) and\nSU(3) pure gauge theories on the lattice. At a temperature of 2 Tc we found\nstrong evidence for dimensional reduction in the non-perturbative spectrum of\nscreening masses. Mass ratios in the high temperature SU(3) theory are\nconsistent with those in the pure gauge theory in three dimensions. At the\nfirst order SU(3) phase transition we report the first measurement of the true\nscalar screening mass."
    },
    {
        "anchor": "$D_{s}$ mesons with $DK$ and $D^{*}K$ scattering near threshold: $D_s$ mesons are studied in three quantum channels ($J^P=0^+$, $1^+$ and\n$2^+$), where experiments have identified the very narrow $D_{s0}^*(2317)$,\n$D_{s1}(2460)$ and narrow $D_{s1}(2536)$, $D_{s2}^*(2573)$. We explore the\neffect of nearby $DK$ and $D^*K$ thresholds on the subthreshold states using\nlattice QCD. Our simulation is done on two very different ensembles of gauge\nconfigurations (2 or 2+1 dynamical quarks, Pion mass of 266 or 156 MeV, lattice\nsize $16^3\\times 32$ or $32^3\\times 64$). In addition to $\\bar{q}q$ operators\nwe also include meson-meson interpolators in the correlation functions. This\nclarifies the identification of the states above and below the scattering\nthresholds. The ensemble with $m_\\pi \\simeq 156~$MeV renders the $D_{s1}(2460)$\nas a strong interaction bound state 44(10)MeV below $D^*K$ threshold, which is\nin agreement with the experiment. The $D_{s0}^*(2317)$ is found 37(17)MeV below\n$DK$ threshold, close to experiment value of 45MeV. The narrow resonances\n$D_{s1}(2536)$ and $D_{s2}^*(2573)$ are also found close to the experimental\nmasses.",
        "positive": "Improved Wilson QCD simulations with light quark masses: We present results from simulations using 2 flavours of O(a)-improved Wilson\nquarks whose masses are about 1/3 of the physical strange quark mass. We\npresent new data on the mass of the singlet pseudoscalar meson and evidence of\nthe onset of chiral logarithms in the pion decay constant. The previously\nobserved suppression of the topological susceptibility at lighter quark masses\nis confirmed. We report on the performance of the hybrid Monte Carlo algorithm\nat light quark masses."
    },
    {
        "anchor": "Topological susceptibility in finite temperature (2+1)-flavor QCD using\n  gradient flow: We compute the topological charge and its susceptibility in finite\ntemperature (2+1)-flavor QCD on the lattice applying a gradient flow method.\nWith the Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson\nquarks, we perform simulations on a fine lattice\nwith~$a\\simeq0.07\\,\\mathrm{fm}$ at a heavy $u$, $d$ quark mass with\n$m_\\pi/m_\\rho\\simeq0.63$ but approximately physical $s$ quark mass with\n$m_{\\eta_{ss}}/m_\\phi\\simeq0.74$. In a temperature range\nfrom~$T\\simeq174\\,\\mathrm{MeV}$ ($N_t=16$) to $697\\,\\mathrm{MeV}$ ($N_t=4$), we\nstudy two topics on the topological susceptibility. One is a comparison of\ngluonic and fermionic definitions of the topological susceptibility. Because\nthe two definitions are related by chiral Ward-Takahashi identities, their\nequivalence is not trivial for lattice quarks which violate the chiral symmetry\nexplicitly at finite lattice spacings. The gradient flow method enables us to\ncompute them without being bothered by the chiral violation. We find a good\nagreement between the two definitions with Wilson quarks. The other is a\ncomparison with a prediction of the dilute instanton gas approximation, which\nis relevant in a study of axions as a candidate of the dark matter in the\nevolution of the Universe. We find that the topological susceptibility shows a\ndecrease in $T$ which is consistent with the predicted $\\chi_\\mathrm{t}(T)\n\\propto (T/T_{\\rm pc})^{-8}$ for three-flavor QCD even at low temperature\n$T_{\\rm pc} < T\\le1.5 T_{\\rm pc}$.",
        "positive": "Deconfinement, Center Symmetry and the Ghost Propagator in Landau Gauge\n  Pure SU(3) Yang-Mills Theory: The temperature dependence of the Landau gauge ghost propagator is\ninvestigated in pure SU(3) Yang-Mills theory with lattice QCD simulations. Its\nbehavior around the confined-deconfined phase transition temperature, $T_c \\sim\n270$ MeV, is investigated. The simulations show that in the deconfined phase,\nthe ghost propagator is enhanced for small momenta, $\\lesssim 1$ GeV.\nFurthermore, the analysis of the spontaneous breaking of center symmetry on the\nghost propagator is studied. Similarly as observed for the gluon propagator,\nthe simulations result in a decoupling of the sectors where the phase of the\nPolyakov loop is either 0 or $\\pm 2\\pi/3$ sectors, with the latter remaining\nindistinguishable. The results point to the possible use of the ghost\npropagator as an \"order parameter\" for the confined-deconfined phase\ntransition."
    },
    {
        "anchor": "Euclidean partons?: In this talk we reexamine the possibility of evaluating parton distribution\nfunctions from lattice simulations. We show that, while in principle individual\nmoments can be extracted from lattice data, in all cases the process of\nrenormalization, hindered by lattice momenta limitation, represents an\nobstruction to a direct calculation of the full parton distribution function\nfrom QCD simulations. We discuss the case of the Ji quasi-parton distribution\nfunctions, the possibility of using the reduced Ioffe-time distributions and\nthe more recent proposal of directly subtracting power divergent mixings in\nperturbation theory.",
        "positive": "Matrix Elements for $D$- and $B$-Mixing from 2+1 Flavor Lattice QCD: We present the status of our calculation of hadronic matrix elements for $D$-\nand $B$-meson mixing. We use a large set of the MILC collaboration's $N_f=2+1$\nasqtad ensembles, which includes lattice spacings in the range\n$a\\approx0.12$-0.045 fm, and up/down to strange quark mass ratios as low as\n0.05. The asqtad action is also employed for the light valence quarks. For the\nheavy quarks we use the Sheikholeslami-Wohlert action with the Fermilab\ninterpretation. Our calculation covers the complete set of five local operators\nneeded to describe $B$-meson mixing in the Standard Model and Beyond. In the\ncharm sector, our calculation of local mixing matrix elements may be used to\nconstrain new physics models. We present final correlator fit results on the\nfull data set for the $B$-meson mixing project and preliminary fit results for\nthe $D$-meson mixing project."
    },
    {
        "anchor": "Loop Representations of the Quark Determinant in Lattice QCD: The modelling of the ultraviolet contributions to the quark determinant in\nlattice QCD in terms of a small number of Wilson loops is examined. Complete\nDirac spectra are obtained for sizeable ensembles of SU(3) gauge fields at\n$\\beta$=5.7 on 6$^4$, 8$^4$, and 10$^4$ lattices allowing for the first time a\ndetailed study of the volume dependence of the effective loop action generating\nthe quark determinant. The connection to the hopping parameter expansion is\nexamined in the heavy quark limit. We compare the efficiency and accuracy of\nvarious methods- specifically, Lanczos versus stochastic approaches- for\nextracting the quark determinant on an ensemble of configurations.",
        "positive": "Dual Meissner Effect and String Tension in SU(2) Lattice Gauge Theory: We study the distribution of the color fields due to a static quark-antiquark\npair in SU(2) lattice gauge theory. We find that the London penetration length\nmeasured after Abelian projection in the Abelian Covariant gauge (Maximal\nAbelian gauge) agrees with the one obtained without gauge fixing. Moreover the\npenetration length scales according to asymptotic freedom. We put out a simple\nrelation between the penetration length and the string tension."
    },
    {
        "anchor": "Molecular dynamics for full QCD simulations with an improved action: I derive the equation of motion in molecular dynamics for doing full lattice\nQCD simulations with clover quarks. The even-odd preconditioning technique,\nexpected to significantly reduce the computational effort, is further developed\nfor the simulations.",
        "positive": "Baryon Octet to Decuplet Electromagnetic Transitions: The electromagnetic transition moments of the $SU(3)$-flavor baryon octet to\ndecuplet are examined within a lattice simulation of quenched QCD. The magnetic\ntransition moment for the $N \\; \\gamma \\to \\Delta$ channel is found to be in\nagreement with recent experimental analyses. The lattice results indicate\n$\\mu_{p \\Delta} / \\mu_p = 0.88(15)$. In terms of the Particle Data Group\nconvention, $f_{M1} = 0.231(41)$ GeV${}^{-1/2}$ for $p \\; \\gamma \\to \\Delta^+$\ntransitions. Lattice predictions for the hyperon $M1$ transition moments agree\nwith those of a simple quark model. However the manner in which the quarks\ncontribute to the transition moments in the lattice simulation is different\nfrom that anticipated by quark model calculations. The scalar quadrupole form\nfactor exhibits a behavior consistent with previous multipole analyses. The\n$E2/M1$ multipole transition moment ratios are also determined. The lattice\nresults suggest $R_{EM} \\equiv -{\\cal G}_{E2}/{\\cal G}_{M1} = +3\\pm 8$ \\% for\n$p \\; \\gamma \\to \\Delta^+$ transitions. Of particular interest are significant\nnonvanishing signals for the $E2/M1$ ratio in $\\Xi^-$ and $\\Sigma^-$\nelectromagnetic transitions."
    },
    {
        "anchor": "An introduction to lattice hadron spectroscopy for students without\n  quantum field theoretical background: The intention of these lecture notes is to outline the basics of lattice\nhadron spectroscopy to students from other fields of physics, e.g. from\nexperimental particle physics, who do not necessarily have a background in\nquantum field theory. After a brief motivation and discussion of QCD, it is\nexplained, how QCD can in principle be solved numerically using lattice QCD.\nThe main part of these lecture notes is concerned with quantum numbers of\nhadrons, corresponding hadron creation operators, and how the mass of a hadron\ncan be determined from a temporal correlation function of such operators.\nFinally, three recent lattice hadron spectroscopy examples from the literature\nare discussed on an elementary level.",
        "positive": "Matrix elements of $\u0394B=0$ operators in heavy hadron chiral\n  perturbation theory: We study the light-quark mass and spatial volume dependence of the matrix\nelements of $\\Delta B=0$ four-quark operators relevant for the determination of\n$V_{ub}$ and the lifetime ratios of single-$b$ hadrons. To this end, one-loop\ndiagrams are computed in the framework of heavy hadron chiral perturbation\ntheory with partially quenched formalism for three light-quark flavors in the\nisospin limit; flavor-connected and -disconnected diagrams are carefully\nanalyzed. These calculations include the leading light-quark flavor and\nheavy-quark spin symmetry breaking effects in the heavy hadron spectrum. Our\nresults can be used in the chiral extrapolation of lattice calculations of the\nmatrix elements to the physical light-quark masses and to infinite volume. To\nprovide insight on such chiral extrapolation, we evaluate the one-loop\ncontributions to the matrix elements containing external $B_d$, $B_s$ mesons\nand $\\Lambda_b$ baryon in the QCD limit, where sea and valence quark masses\nbecome equal. In particular, we find that the matrix elements of the\n$\\lambda_3$ flavor-octet operators with external $B_d$ meson receive the\ncontributions solely from connected diagrams in which current lattice\ntechniques are capable of precise determination of the matrix elements. Finite\nvolume effects are at most a few percent for typical lattice sizes and pion\nmasses."
    },
    {
        "anchor": "Bottom hadrons from lattice QCD with domain wall and NRQCD fermions: Dynamical 2+1 flavor lattice QCD is used to calculate the masses of bottom\nhadrons, including B mesons, singly and doubly bottom baryons, and for the\nfirst time also the triply-bottom baryon Omega_bbb. The domain wall action is\nused for the up-, down-, and strange quarks (both valence and sea), while the\nbottom quark is implemented with non-relativistic QCD. A calculation of the\nbottomonium spectrum is also presented.",
        "positive": "Revisiting the pentaquark episode for lattice QCD: This work revisits the pentaquark episode, particularly in reference to\nlattice QCD, to collect in one place the lessons that have been or should be\nlearnt. This also examines whether, and if yes, where, there might be any\nprospect for future studies of pentaquarks and the role of lattice QCD in it.\nTests such as volume dependence, and hybrid boundary conditions to distinguish\nbound and scattering states are identified as the positives to take forward\nfrom this episode. On the other hand it is also observed that pentaquarks with\nheavier quark content and in the $SU(3)_f$ limit may still be worth not\nforgetting, and in that case lattice QCD may have an important role to play."
    },
    {
        "anchor": "Glueball Properties at Finite Temperature: We study the glueball properties at finite temperature below T_c using SU(3)\nanisotropic quenched lattice QCD with beta=6.25, the renormalized anisotropy\ngamma = a_s/a_t = 4 and 20^3 \\times N_t (N_t = 35, 36, 37, 38, 40, 43, 45, 50,\n72). From the temporal correlation analysis with the smearing method, we\nobserve the mass reduction of about 20 % for the lowest 0^{++} glueball as\nm_G(T) = 1.25 \\pm 0.1 GeV for 0.8 T_c < T < T_c in comparison with m_G \\simeq\n1.5 \\sim 1.7 GeV at T \\sim 0.",
        "positive": "Spectral functions and critical dynamics of the $O(4)$ model from\n  classical-statistical lattice simulations: We calculate spectral functions of the relativistic $O(4)$ model from\nreal-time lattice simulations in classical-statistical field theory. While in\nthe low and high temperature phase of the model, the spectral functions of\nlongitudinal $(\\sigma)$ and transverse $(\\pi)$ modes are well described by\nrelativistic quasi-particle peaks, we find a highly non-trivial behavior of the\nspectral functions in the cross over region, where additional structures\nappear. Similarly, we observe a significant broadening of the quasi-particle\npeaks, when the amount explicit $O(4)$ symmetry breaking is reduced. We further\ndemonstrate that in the vicinity of the $O(4)$ critical point, the spectral\nfunctions develop an infrared power law associated with the critical dynamics,\nand comment on the extraction of the dynamical critical exponent $z$ from our\nsimulations."
    },
    {
        "anchor": "Gluinos condensing at the CCNI: 4096 CPUs weigh in: We report preliminary results of lattice super-Yang-Mills computations using\ndomain wall fermions, performed at an actual rate of 1000 Gflop/s, over the\ncourse of six months, using two BlueGene/L racks at Rensselaer's CCNI\nsupercomputing center. This has allowed us to compute the gluino condensate and\nstring tension over a wide range of lattice parameters, setting the stage for\ncontinuum, chiral extrapolations.",
        "positive": "Dynamic Critical Behavior of a Swendsen-Wang-Type Algorithm for the\n  Ashkin-Teller Model: We study the dynamic critical behavior of a Swendsen-Wang-type algorithm for\nthe Ashkin--Teller model. We find that the Li--Sokal bound on the\nautocorrelation time ($\\tau_{{\\rm int},{\\cal E}} \\ge {\\rm const} \\times C_H$)\nholds along the self-dual curve of the symmetric Ashkin--Teller model, and is\nalmost but not quite sharp. The ratio $\\tau_{{\\rm int},{\\cal E}} / C_H$ appears\nto tend to infinity either as a logarithm or as a small power ($0.05 \\leq p\n\\leq 0.12$). In an appendix we discuss the problem of extracting estimates of\nthe exponential autocorrelation time."
    },
    {
        "anchor": "Isovector and flavor-diagonal charges of the nucleon: We present an update on the status of the calculations of isovector and\nflavor-diagonal charges of the nucleon. The calculations of the isovector\ncharges are being done using ten $2+1+1$-flavor HISQ ensembles generated by the\nMILC collaboration covering the range of lattice spacings $a \\approx$ 0.12,\n0.09, 0.06 fm and pion masses $M_\\pi \\approx$ 310, 220, 130 MeV. Excited-states\ncontamination is controlled by using four-state fits to two-point correlators\nand three-states fits to the three-point correlators. The calculations of the\ndisconnected diagrams needed to estimate flavor-diagonal charges are being done\non a subset of six ensembles using the stocastic method. Final results are\nobtained using a simultaneous fit in $M_\\pi^2$, the lattice spacing $a$ and the\nfinite volume parameter $M_\\pi L$ keeping only the leading order corrections.",
        "positive": "Non-zero temperature study of spin 1/2 charmed baryons using lattice\n  gauge theory: We study the behaviour of spin $1/2$ charmed baryons as the temperature\nincreases. We make use of anisotropic lattice QCD simulations with $N_f = 2 +\n1$ dynamical flavours. After determining the positive and negative parity\nground state masses at the lowest temperature, we investigate the effect of\nrising temperature using ratios of thermal lattice correlators with both\nso-called reconstructed correlators and with simple model correlators. This\navoids difficulties associated with non-zero temperature fitting or spectral\nreconstruction. We find that temperature effects are prominent throughout the\nhadronic phase for all negative parity channels considered and for some\npositive parity channels. Subsequently and where possible, we determine the\nmasses of the ground states as a function of temperature. Finally we consider\nthe effect of chiral symmetry restoration and extract an estimate of the\npseudocritical temperature from singly charmed baryonic correlators."
    },
    {
        "anchor": "Cutoff effects of Wilson fermions in the absence of spontaneous chiral\n  symmetry breaking: We simulate two dimensional QED with two degenerate Wilson fermions and\nplaquette gauge action. As a consequence of the Mermin-Wagner theorem, in the\ncontinuum limit chiral symmetry is realized a la Wigner. This property affects\nalso the size of the cutoff effects. That can be understood in view of the fact\nthat the leading lattice artifacts are described, in the continuum Symanzik\neffective theory, by chirality breaking terms. In particular, vacuum\nexpectation values of non-chirality-breaking operators are expected to be O(a)\nimproved in the chiral limit. We provide a numerical confirmation of this\nexpectation by performing a scaling test.",
        "positive": "Effects of non-equilibrated topological charge distributions on\n  pseudoscalar meson masses and decay constants: We study the effects of failure to equilibrate the squared topological charge\n$Q^2$ on lattice calculations of pseudoscalar masses and decay constants. The\nanalysis is based on chiral perturbation theory calculations of the dependence\nof these quantities on the QCD vacuum angle $\\theta$. For the light-light\npartially quenched case, we rederive the known chiral perturbation theory\nresults of Aoki and Fukaya, but using the nonperturbatively-valid chiral theory\nworked out by Golterman, Sharpe and Singleton, and by Sharpe and Shoresh. We\nthen extend these calculations to heavy-light mesons. Results when staggered\ntaste-violations are important are also presented. The derived $Q^2$ dependence\nis compared to that of simulations using the MILC collaboration's ensembles of\nlattices with four flavors of HISQ dynamical quarks. We find agreement, albeit\nwith large statistical errors. These results can be used to correct for the\nleading effects of unequilibrated $Q^2$, or to make estimates of the systematic\nerror coming from the failure to equilibrate $Q^2$. In an appendix, we show\nthat the partially quenched chiral theory may be extended beyond a lower bound\non valence masses discovered by Sharpe and Shoresh. Subtleties occurring when a\nsea-quark mass vanishes are discussed in another appendix."
    },
    {
        "anchor": "Finite size scaling in minimal walking technicolor: We compare observables to the finite size scaling hypothesis in SU(2) lattice\ngauge theory with two Dirac fermions in the adjoint representation. The fits\nthat we obtain yield an estimate of the anomalous mass dimension that is\nconsistent with four loop perturbation theory: $\\gamma = 0.51 \\pm 0.16$, with\nthe error due to systematic uncertainties in the finite size scaling analysis.\nThe result is somewhat larger than one Schr\\\"odinger functional study (by\n1.3$\\sigma$) but consistent with another.",
        "positive": "Infinite Variance in Monte Carlo Sampling of Lattice Field Theories: In Monte Carlo calculations of expectation values in lattice quantum field\ntheories, the stochastic variance of the sampling procedure that is used\ndefines the precision of the calculation for a fixed number of samples. If the\nvariance of an estimator of a particular quantity is formally infinite, or in\npractice very large compared to the square of the mean, then that quantity can\nnot be reliably estimated using the given sampling procedure. There are\nmultiple scenarios in which this occurs, including in Lattice Quantum\nChromodynamics, and a particularly simple example is given by the Gross-Neveu\nmodel where Monte Carlo calculations involve the introduction of auxiliary\nbosonic variables through a Hubbard-Stratonovich (HS) transformation. Here, it\nis shown that the variances of HS estimators for classes of operators involving\nfermion fields are divergent in this model and an even simpler zero-dimensional\nanalogue. To correctly estimate these observables, two alternative sampling\nmethods are proposed and numerically investigated."
    },
    {
        "anchor": "Comment on Implications of new physics in the decays $B_c \\to\n  (J/\u03c8,\u03b7_c)\u03c4\u03bd$: As part of a study BSM corrections to leptonic decays of the $B_c$ meson,\nTran et al. (arXiv:1801.06927) use the covariant confining quark model (CCQM)\nto estimate the matrix element of the pseudo-scalar curent between the vacuum\nand the $B_c$ meson. We note that this matrix element can be determined using\nexisting lattice QCD results.",
        "positive": "Gluon Field Digitization via Group Space Decimation for Quantum\n  Computers: Efficient digitization is required for quantum simulations of gauge theories.\nSchemes based on discrete subgroups use fewer qubits at the cost of systematic\nerrors. We systematize this approach by deriving a single plaquette action for\napproximating general continuous gauge groups through integrating out field\nfluctuations. This provides insight into the effectiveness of these\napproximations, and how they could be improved. We accompany the scheme by\nsimulations of pure gauge over the largest discrete subgroup of $SU(3)$ up to\nthe third order."
    },
    {
        "anchor": "'t Hooft-Polyakov monopoles in lattice SU(N)+adjoint Higgs theory: We investigate twisted C-periodic boundary conditions in SU(N) gauge field\ntheory with an adjoint Higgs field. We show that with a suitable twist for even\nN one can impose a non-zero magnetic charge relative to residual U(1) gauge\ngroups in the broken phase, thereby creating a 't Hooft-Polyakov magnetic\nmonopole. This makes it possible to use lattice Monte-Carlo simulations to\nstudy the properties of these monopoles in the quantum theory.",
        "positive": "A lattice study of $\u03c0\u03c0$ scattering at large $N_\\text{c}$: We present the first lattice study of pion-pion scattering with varying\nnumber of colors, $N_\\text{c}$. We use lattice simulations with four degenerate\nquark flavors, $N_\\text{f}=4$, and $N_\\text{c}=3-6$. We focus on two scattering\nchannels that do not involve vacuum diagrams. These correspond to two\nirreducible representations of the SU(4) flavor group: the fully symmetric one,\n$SS$, and the fully antisymmetric one, $AA$. The former is a repulsive channel\nequivalent to the isospin-2 channel of SU(2). By contrast, the latter is\nattractive and only exists for $N_\\text{f} \\geq 4$. A representative state is\n$\\left( |D_s^+ \\pi^+\\rangle - |D^+ K^+\\rangle\\right)/\\sqrt{2}$. Using\nL\\\"uscher's formalism, we extract the near-threshold scattering amplitude and\nwe match our results to Chiral Perturbation Theory (ChPT) at large\n$N_\\text{c}$. For this, we compute the analytical U$(N_\\text{f})$ ChPT\nprediction for two-pion scattering, and use the lattice results to constrain\nthe $N_\\text{c}$ scaling of the relevant low-energy couplings."
    },
    {
        "anchor": "A Non-Perturbative Operator Product Expansion: Nucleon structure functions can be observed in Deep Inelastic Scattering\nexperiments, but it is an outstanding challenge to confront them with fully\nnon-perturbative QCD results. For this purpose we investigate the product of\nelectromagnetic currents (with large photon momenta) between quark states (of\nlow momenta). By means of an Operator Product Expansion the structure function\ncan be decomposed into matrix elements of local operators, and Wilson\ncoefficients. For consistency both have to be computed non-perturbatively. Here\nwe present precision results for a set of Wilson coefficients. They are\nevaluated from propagators for numerous quark momenta on the lattice, where the\nuse of chiral fermions suppresses undesired operator mixing. This\nover-determines the Wilson coefficients, but reliable results can be extracted\nby means of a Singular Value Decomposition.",
        "positive": "The Width of the Confining String in Yang-Mills Theory: We investigate the transverse fluctuations of the confining string connecting\ntwo static quarks in (2+1)-d SU(2) Yang-Mills theory using Monte Carlo\ncalculations. The exponentially suppressed signal is extracted from the large\nnoise by a very efficient multi-level algorithm. The resulting width of the\nstring increases logarithmically with the distance between the static quark\ncharges. Corrections at intermediate distances due to universal higher order\nterms in the effective string action are calculated analytically. They\naccurately fit the numerical data."
    },
    {
        "anchor": "Semi-vortices and cluster-vorticity: new concepts in the\n  Berezinskii-Kosterlitz-Thouless phase transition: The Berezinskii-Kosterlitz-Thouless (BKT) essential phase transition in the\n2d XY model is revisited. Its mechanism is usually described by the (un)binding\nof vortex--anti-vortex (V--AV) pairs, which does, however, not provide a\nclear-cut quantitative criterion for criticality. Known sharp criteria are the\ndivergence of the correlation length and a discontinuity of the helicity\nmodulus. Here we propose and probe a new criterion: it is based on the concepts\nof semi-vortices and cluster vorticity, which are formulated in the framework\nof the multi-cluster algorithm that we use to simulate the 2d XY model.",
        "positive": "Gribov Copy and Complex Phase of Chiral Determinant: We calculate the complex phase of chiral determinant by the vacuum overlap\nformula with configurations of two-dimensional U(1) gauge field fixed in Landau\nand Laplacian gauge. The complex phase fluctuates over the Gribov copies, which\nappear in the process of Landau gauge fixing and contain vortex-like\nsingularities. In the Laplacian gauge, the fluctuation can be reduced and the\nphase can be determined uniquely. If it is used as a preconditioning for Landau\ngauge fixing, the most smooth configuration is obtained among the copies\ngenerated."
    },
    {
        "anchor": "Nucleons near the QCD deconfinement transition: Using non-perturbative lattice method we studied hadronic screening\ncorrelators above and immediately below the deconfinement transition\ntemperature, Tc, in the quenched approximation with lattice spacing of 1/(8T)\nusing clover improved Wilson fermions. Simulations were performed at\ntemperatures T /Tc = 0, 0.95 and 1.5. Mesonic screening correlators show no\nstatistically significant thermal effects below Tc, and clear evidence for\nweakly interacting quarks above Tc . Baryon screening correlators yield similar\nphysics above Tc, but show precursor effects for chiral symmetry restoration\nbelow Tc .",
        "positive": "Machine-Learning Prediction for Quasi-PDF Matrix Elements: There have been rapid developments in the direct calculation in lattice QCD\n(LQCD) of the Bjorken-$x$ dependence of hadron structure through large-momentum\neffective theory (LaMET). LaMET overcomes the previous limitation of LQCD to\nmoments (that is, integrals over Bjorken-$x$) of hadron structure, allowing\nLQCD to directly provide the kinematic regions where the experimental values\nare least known. LaMET requires large-momentum hadron states to minimize its\nsystematics and allow us to reach small-$x$ reliably. This means that very fine\nlattice spacing to minimize lattice artifacts at order $(P_z a)^n$ will become\ncrucial for next-generation LaMET-like structure calculations. Furthermore,\nsuch calculations require operators with long Wilson-link displacements (in\nfiner lattice units), increasing the communication costs relative to that of\nthe propagator inversion. In this work, we explore whether machine-learning\n(ML) algorithms can make correlator predictions to reduce the computational\ncost of these LQCD calculations. We consider two algorithms, gradient-boosting\ndecision tree and linear models, applied to LaMET data, the matrix elements\nneeded to determine the kaon and $\\eta_s$ unpolarized parton distribution\nfunctions (PDFs), meson distribution amplitude (DA), and the nucleon gluon PDF.\nWe find that both algorithms can reliably predict the target observables with\ndifferent fit quality and systematic errors. The predictions from smaller\ndisplacement $z$ to larger ones work better than those for momentum $p$ due to\nthe higher correlation among the data."
    },
    {
        "anchor": "Non-trivial Center Dominance in High Temperature QCD: We investigate the properties of quarks and gluons above the chiral phase\ntransition temperature $T_c,$ using the RG improved gauge action and the Wilson\nquark action with two degenerate quarks mainly on a $32^3\\times 16$ lattice. In\nthe one-loop perturbation theory, the thermal ensemble is dominated by the\ngauge configurations with effectively $Z(3)$ center twisted boundary\nconditions, making the thermal expectation value of the spatial Polyakov loop\ntake a non-trivial $Z(3)$ center. This is in agreement with our lattice\nsimulation of high temperature QCD. We further observe that the temporal\npropagator of massless quarks at extremely high temperature $\\beta=100.0 \\, (T\n\\simeq10^{58} T_c)$ remarkably agrees with the temporal propagator of free\nquarks with the $Z(3)$ twisted boundary condition for $t/L_t \\geq 0.2$, but\ndiffers from that with the $Z(3)$ trivial boundary condition. As we increase\nthe mass of quarks $m_q$, we find that the thermal ensemble continues to be\ndominated by the $Z(3)$ twisted gauge field configurations as long as $m_q \\le\n3.0 \\, T$ and above that the $Z(3)$ trivial configurations come in. The\ntransition is essentially identical to what we found in the departure from the\nconformal region in the zero-temperature many-flavor conformal QCD on a finite\nlattice by increasing the mass of quarks. We argue that the behavior is\nconsistent with the renormalization group analysis at finite temperature.",
        "positive": "Non-Abelian dual superconductivity and Gluon propagators in the deep IR\n  region for SU(3) Yang-Mills theory: We have proposed the non-Abelian dual superconductivity picture for quark\nconfinement in the SU(3) Yang-Mills (YM) theory, and have given numerical\nevidences for the restricted-field dominance and the non-Abelian magnetic\nmonopole dominance in the string tension by applying a new formulation of the\nYM theory on a lattice. To establish the non-Abelian dual superconductivity\npicture for quark confinement, we have observed the non-Abelian dual Meissner\neffect in the SU(3) Yang-Mills theory by measuring the chromoelectric flux\ncreated by the quark-antiquark source, and the non-Abelian magnetic monopole\ncurrents induced around the flux. We conclude that the dual superconductivity\nof the SU(3) Yang-Mills theory is strictly the type I and that this type of\ndual superconductivity is reproduced by the restricted field and the\nnon-Abelian magnetic monopole part, in sharp contrast to the SU(2) case: the\nborder of type I and type II."
    },
    {
        "anchor": "Emergence of the $\u03c1$ resonance from the HAL QCD potential in lattice\n  QCD: We investigate the $I=1$ $\\pi \\pi$ interaction using the HAL QCD method in\nlattice QCD. We employ the (2+1)-flavor gauge configurations on $32^3 \\times\n64$ lattice at the lattice spacing $a \\approx 0.0907$ fm and $m_{\\pi} \\approx\n411$ MeV, in which the $\\rho$ meson appears as a resonance state. We find that\nall-to-all propagators necessary in this calculation can be obtained with\nreasonable precision by a combination of three techniques, the one-end trick,\nthe sequential propagator, and the covariant approximation averaging (CAA). The\nnon-local $I=1$ $\\pi \\pi$ potential is determined at the\nnext-to-next-to-leading order (N$^2$LO) of the derivative expansion for the\nfirst time, and the resonance parameters of the $\\rho$ meson are extracted. The\nobtained $\\rho$ meson mass is found to be consistent with the value in the\nliterature, while the value of the coupling $g_{\\rho \\pi \\pi}$ turns out to be\nsomewhat larger. The latter observation is most likely attributed to the lack\nof low-energy information in our lattice setup with the center-of-mass frame.\nSuch a limitation may appear in other P-wave resonant systems and we discuss\npossible improvement in future. With this caution in mind, we positively\nconclude that we can reasonably extract the N$^2$LO potential and resonance\nparameters even in the system requiring the all-to-all propagators in the HAL\nQCD method, which opens up new possibilities for the study of resonances in\nlattice QCD.",
        "positive": "Aliasing modes in the lattice Schwinger model: We study the Schwinger model on a lattice consisting of zeros of the Hermite\npolynomials that incorporates a lattice derivative and a discrete Fourier\ntransform with many properties. Such a lattice produces a Klein-Gordon equation\nfor the boson field and the exact value of the mass in the asymptotic limit if\nthe boundaries are not taken into account. On the contrary, if the lattice is\nconsidered with boundaries new modes appear due to aliasing effects. In the\ncontinuum limit, however, this lattice yields also a Klein-Gordon equation with\na reduced mass."
    },
    {
        "anchor": "Progress in three-particle scattering from LQCD: We present the status of our formalism for extracting three-particle\nscattering observables from lattice QCD (LQCD). The method relies on relating\nthe discrete finite-volume spectrum of a quantum field theory with its\nscattering amplitudes. As the finite-volume spectrum can be directly determined\nin LQCD, this provides a method for determining scattering observables, and\nassociated resonance properties, from the underlying theory. In a pair of\npapers published over the last two years, two of us have extended this approach\nto apply to relativistic three-particle scattering states. In this talk we\nsummarize recent progress in checking and further extending this result. We\ndescribe an extension of the formalism to include systems in which two-to-three\ntransitions can occur. We then present a check of the previously published\nformalism, in which we reproduce the known finite-volume energy shift of a\nthree-particle bound state.",
        "positive": "Multigrid Methods in Lattice Field Computations: The multigrid methodology is reviewed. By integrating numerical processes at\nall scales of a problem, it seeks to perform various computational tasks at a\ncost that rises as slowly as possible as a function of $n$, the number of\ndegrees of freedom in the problem. Current and potential benefits for lattice\nfield computations are outlined. They include: $O(n)$ solution of Dirac\nequations; just $O(1)$ operations in updating the solution (upon any local\nchange of data, including the gauge field); similar efficiency in gauge fixing\nand updating; $O(1)$ operations in updating the inverse matrix and in\ncalculating the change in the logarithm of its determinant; $O(n)$ operations\nper producing each independent configuration in statistical simulations\n(eliminating CSD), and, more important, effectively just $O(1)$ operations per\neach independent measurement (eliminating the volume factor as well). These\npotential capabilities have been demonstrated on simple model problems.\nExtensions to real life are explored."
    },
    {
        "anchor": "Preliminary Results with Lattice Covariant Gauge: In this poster we present a few preliminary results obtained using our method\nto fix generic covariant gauges on the lattice. We have computed the gluon\npropagator and we have found a sensitive dependence on the gauge parameter.",
        "positive": "Eigenspectrum Noise Subtraction Methods in Lattice QCD: We propose a new noise subtraction method, which we call \"eigenspectrum\nsubtraction\", which uses low eigenmode information to suppress statistical\nnoise at low quark mass. This is useful for lattice calculations involving\ndisconnected loops or all-to-all propagators. It has significant advantages\nover perturbative subtraction methods. We compare unsubtracted, eigenspectrum\nand perturbative error bar results for the scalar operator on a small Wilson\nQCD matrix."
    },
    {
        "anchor": "Sub-leading conformal dimensions at the O(4) Wilson-Fisher fixed point: In this work we focus on computing the conformal dimensions $D(j_L,j_R)$ of\nlocal fields that transform in an irreducible representation of $SU(2) \\times\nSU(2)$ labeled with $(j_L,j_R)$ at the $O(4)$ Wilson-Fisher fixed point using\nthe Monte Carlo method. In the large charge expansion, among the sectors with a\nfixed large value of $j = {\\rm max}(j_L,j_R)$, the leading sector has\n$|j_L-j_R| = 0$ and the sub-leading one has $|j_L-j_R| = 1$. Since Monte Carlo\ncalculations at large $j$ become challenging in the traditional lattice\nformulation of the $O(4)$ model, a qubit regularized $O(4)$ lattice model was\nused recently to compute $D(j,j)$. Here we extend those calculations to the\nsub-leading sector. Our Monte Carlo results up to $j=20$ fit well to the form\n$D(j,j-1)-D(j) \\sim \\lambda_{1/2}/\\sqrt{j} + \\lambda_1/j +\n\\lambda_{3/2}/j^{3/2}$, consistent with recent predictions of the large charge\nexpansion. Taking into account systematic effects in our fitting procedures we\nestimate the two leading coefficients to be $\\lambda_{1/2}=2.08(5)$,\n$\\lambda_1=2.2(3)$.",
        "positive": "Exact lattice chiral symmetry in 2d gauge theory: We construct symmetry-preserving lattice regularizations of 2d QED with one\nand two flavors of Dirac fermions, as well as the `3450' chiral gauge theory,\nby leveraging bosonization and recently-proposed modifications of Villain-type\nlattice actions. The internal global symmetries act just as locally on the\nlattice as they do in the continuum, the anomalies are reproduced at finite\nlattice spacing, and in each case we find a sign-problem-free dual formulation."
    },
    {
        "anchor": "Monopole density around static color sources: We analyze the vacuum structure with respect to magnetic monopoles of\nquenched QCD in the presence of static color sources. Distributions of the\nmonopole density around static quarks and mesons are computed in both phases of\nQCD. We observe a suppression of the monopole density in the vicinity of\nexternal sources. In the confinement phase the density of color magnetic\nmonopoles is reduced along the flux tube between a static quark-antiquark pair.",
        "positive": "Polyakov loops and the Hosotani mechanism on the lattice: We explore the phase structure and symmetry breaking in four-dimensional\nSU(3) gauge theory with one spatial compact dimension on the lattice ($16^3\n\\times 4$ lattice) in the presence of fermions in the adjoint representation\nwith periodic boundary conditions. We estimate numerically the density plots of\nthe Polyakov loop eigenvalues phases, which reflect the location of minima of\nthe effective potential in the Hosotani mechanism. We find strong indication\nthat the four phases found on the lattice correspond to SU(3)-confined,\nSU(3)-deconfined, SU(2) x U(1), and U(1) x U(1) phases predicted by the\none-loop perturbative calculation. The case with fermions in the fundamental\nrepresentation with general boundary conditions, equivalent to the case of\nimaginary chemical potentials, is also found to support the $Z_3$ symmetry\nbreaking in the effective potential analysis."
    },
    {
        "anchor": "Infrared features of KS fermion and Wilson fermion in Lattice Landau\n  Gauge QCD: The running coupling and the Kugo-Ojima parameter of unquenched lattice\nLandau gauge are simulated and compared with the continuum theory. Presence of\ninfrared fixed point of $\\alpha_0\\sim 2-2.5$ irrespective of the fermion\nactions (Wilson fermions and Kogut-Susskind(KS) fermions) in the continuum and\nin the chiral limit is suggested. Although there exists dependence on the\npolarization due to asymmetry of the lattice (time axis is longer than spacial\naxes), the Kugo-Ojima parameter $c$ is consistent with 1. Presence of\n$1+c_1/q^2$ correction factor in the running coupling depends on the lattice\nsize and the sea quark mass. In the large lattice size and small sea quark\nmass, $c_1\\sim 2.8$GeV is confirmed. The MILC configuration of $a=0.09$fm\nsuggests also presence of dimension 4 condensates with sign opposite to the\ndimension 2 condensates. The gluon propagator, the ghost propagator and the\nrunning coupling are compared with recent pQCD results including anomalous\ndimension of fields up to the 4-loop level.",
        "positive": "Exploring the gluoN_c plasma: We report lattice computations in SU(N_c) pure gauge theory, where N_c is\nincreased beyond the physical value of 3. We demonstrate two-loop scaling of\nT_c, thus obtaining the variation of T_c/Lambda_MSbar with N_c, and fixing the\ntemperature scale. We study the equation of state of the gluoN_c plasma, the\nconformal anomaly, and the approach to the weak coupling theory. We find that\nthe weak-coupling prediction is always closer to the lattice data than the\nconformal field theory is."
    },
    {
        "anchor": "Geometric Origin of Staggered Fermion: Direct Product K-Cycle: Staggered formalism of lattice fermion can be cast into a form of direct\nproduct K-cycle in noncommutative geometry. The correspondence between this\nstaggered K-cycle and a canonically defined K-cycle for finitely generated\nabelian group where lattice appears as a special case is proved.",
        "positive": "Bayesian curve fitting for lattice gauge theorists: A new method of extracting the low-lying energy spectrum from Monte Carlo\nestimates of Euclidean-space correlation functions which incorporates Bayesian\ninference is described and tested. The procedure fully exploits the information\npresent in the correlation functions at small temporal separations and uses\nthis information in a way consistent with fundamental probabilistic hypotheses.\nThe computed errors on the best-fit energies include both statistical\nuncertainties and systematic errors associated with the treatment of\ncontamination from higher-lying stationary states. Difficulties in performing\nthe integrals needed to compute these error estimates are briefly discussed."
    },
    {
        "anchor": "Multi-hadron spectroscopy in a large physical volume: We demonstrate the efficacy of the stochastic LapH method to treat all-to-all\nquark propagation on a $N_f = 2+1$ CLS ensemble with large linear spatial\nextent $L = 5.5$ fm, allowing us to obtain the benchmark elastic isovector\np-wave pion-pion scattering amplitude to good precision already on a relatively\nsmall number of gauge configurations. These results hold promise for\nmulti-hadron spectroscopy at close-to-physical pion mass with exponential\nfinite-volume effects under control.",
        "positive": "General properties of logarithmically divergent one-loop lattice Feynman\n  integrals: We prove that logarithmically divergent one-loop lattice Feynman integrals\nhave the general form I(p,a) = f(p)log(aM)+g(p,M) up to terms which vanish for\nlattice spacing a -> 0. Here p denotes collectively the external momenta and M\nis an arbitrary mass scale. The f(p) is shown to be universal and to coincide\nwith the analogous quantity in the corresponding continuum integral\n(regularized, e.g., by momentum cut-off). This is essential for universality of\nthe lattice QCD beta-function and anomalous dimensions of renormalized lattice\noperators at one loop. The result and argument presented here are simplified\nversions of ones given in arXiv:0709.0781. A noteworthy feature of the argument\nhere is that it does not involve Taylor expansion in external momenta, hence\ninfra-red divergences associated with that expansion do not arise."
    },
    {
        "anchor": "QCD phase diagram with isospin chemical potential: In this contribution we investigate the phase diagram of QCD in the presence\nof an isospin chemical potential. To alleviate the infrared problems of the\ntheory associated with pion condensation, we introduce the pionic source as an\ninfrared regulator. We discuss various methods to extrapolate the results to\nvanishing pionic source, including a novel method based on the singular value\nspectrum of the massive Dirac operator, a leading-order reweighting and a\nspline Monte-Carlo fit. Our main results concern the phase transition boundary\nbetween the normal and the pion condensation phases and the\nchiral/deconfinement transition temperature as a function of the chemical\npotential. In addition, we perform a quantitative comparison between our direct\nresults and a Taylor-expansion obtained at zero chemical potential to assess\nthe applicability range of the latter.",
        "positive": "Discretization Errors for the Gluon and Ghost Propagators in Landau\n  Gauge using NSPT: The subtraction of hypercubic lattice corrections, calculated at 1-loop order\nin lattice perturbation theory (LPT), is common practice, e.g., for\ndeterminations of renormalization constants in lattice hadron physics.\nProviding such corrections beyond 1-loop order is however very demanding in\nLPT, and numerical stochastic perturbation theory (NSPT) might be the better\ncandidate for this. Here we report on a first feasibility check of this method\nand provide (in a parametrization valid for arbitrary lattice couplings) the\nlattice corrections up to 3-loop order for the SU(3) gluon and ghost\npropagators in Landau gauge. These propagators are ideal candidates for such a\ncheck, as they are available from lattice simulations to high precision and can\nbe combined to a renormalization group invariant product (Minimal MOM coupling)\nfor which a 1-loop LPT correction was found to be insufficient to remove the\nbulk of the hypercubic lattice artifacts from the data. As a bonus, we also\ncompare our results with the ever popular H(4) method."
    },
    {
        "anchor": "Fermion-Fermion Scattering in the Gross-Neveu Model - a Status Report: Encouraged by the successful applications of L\\\"uscher's method to\nboson--boson scattering we discuss the possibility of extracting scattering\nphase shifts from finite--volume energies for fermion--fermion scattering in\nthe Gross--Neveu model.",
        "positive": "Gluonic Higgs Scalar, Abelianization and Monopoles in QCD -- Similarity\n  and Difference between QCD in the MA Gauge and the NAH Theory: We study the similarity and the difference between QCD in the maximally\nabelian (MA) gauge and the nonabelian Higgs (NAH) theory by introducing the\n``gluonic Higgs scalar field'' $\\vec \\phi(x)$ corresponding to the\n``color-direction'' of the nonabelian gauge connection. The infrared-relevant\ngluonic mode in QCD can be extracted by the projection along the\ncolor-direction $\\vec \\phi(x)$ like the NAH theory. This projection is\nmanifestly gauge-invariant, and is mathematically equivalent to the ordinary MA\nprojection. Since $\\vec \\phi(x)$ obeys the adjoint gauge transformation and is\ndiagonalized in the MA gauge, $\\vec \\phi(x)$ behaves as the Higgs scalar in the\nNAH theory, and its hedgehog singularity provides the magnetic monopole in the\nMA gauge like the NAH theory. We observe this direct correspondence between the\nmonopole appearing in the MA gauge and the hedgehog singularity of $\\vec\n\\phi(x)$ in lattice QCD, when the gluon field is continuous as in the SU($N_c$)\nLandau gauge. In spite of several similarities, QCD in the MA gauge largely\ndiffers from the NAH theory in the two points: one is infrared monopole\ncondensation, and the other is infrared enhancement of the abelian correlation\ndue to monopole condensation."
    },
    {
        "anchor": "Center Vortices and Topological Charge: I review important aspects of the relation between center vortices and\ntopological charge, leading to chiral symmetry breaking.",
        "positive": "Nucleon axial and pseudoscalar form factors using twisted-mass fermion\n  ensembles at the physical point: We compute the nucleon axial and pseudoscalar form factors using three\n$N_f=$2+1+1 twisted mass fermion ensembles with all quark masses tuned to\napproximately their physical values. The values of the lattice spacings of\nthese three physical point ensembles are 0.080 fm, 0.068 fm, and 0.057 fm, and\nspatial sizes 5.1 fm, 5.44 fm, and 5.47 fm, respectively, yielding $m_\\pi\nL$>3.6. Convergence to the ground state matrix elements is assessed using\nmulti-state fits. We study the momentum dependence of the three form factors\nand check the partially conserved axial-vector current (PCAC) hypothesis and\nthe pion pole dominance (PPD). We show that in the continuum limit, the PCAC\nand PPD relations are satisfied. We also show that the Goldberger-Treimann\nrelation is approximately fulfilled and determine the Goldberger-Treiman\ndiscrepancy. We find for the nucleon axial charge $g_A$=1.245(28)(14), for the\naxial radius $\\langle r^2_A \\rangle$=0.339(48)(06) fm$^2$, for the pion-nucleon\ncoupling constant $g_{\\pi NN} \\equiv \\lim_{Q^2 \\rightarrow -m_\\pi^2} G_{\\pi\nNN}(Q^2)$=13.25(67)(69) and for $G_P(0.88m_{\\mu}^2)\\equiv g_P^*$=8.99(39)(49)."
    },
    {
        "anchor": "Confinement-deconfinement transition in $SU(3)$-Higgs theory: We study lattice cutoff effects on the confinement-deconfinement transition\nand the $Z_3$ symmetry in $SU(3)$-Higgs theory in $3+1$ dimensions. The Higgs\nin this study is a complex triplet with vanishing bare mass and quartic\ncoupling. The lattice cutoff is regulated by varying the number of temporal\nlattice sites, $N_\\tau$. Our results show that the nature of the\nconfinement-deconfinement transition depends on $N_\\tau$. For $N_\\tau=2$ the\ntransition is found to be the end point of a first-order transition and is\nfirst order for $N_\\tau \\ge 3$. The distributions of the Polyakov loop and\nother observables, sensitive to the $Z_3$ symmetry, show that the strength of\n$Z_3$ explicit breaking decreases with $N_\\tau$. Up to $T\\simeq 2T_c$, the free\nenergy difference between $Z_3$ states decreases with $N_\\tau$, suggesting the\nrealization of $Z_3$ symmetry in the continuum limit.",
        "positive": "Ab initio study of QCD thermodynamics on the lattice at zero and finite\n  densities: The WHOT-QCD Collaboration is pushing forward a series of lattice studies of\nQCD at finite temperatures and densities using improved Wilson quarks. Because\nWilson-type quarks require more computational resources than the more widely\nadopted staggered-type quarks, various theoretical and computational techniques\nhave to be developed and applied. In this paper, we introduce the fixed-scale\napproach armed with the T-integration method, the Gaussian method based on the\ncumulant expansion, and the histogram method combined with the reweighting\ntechnique. Adopting these methods, we have carried out the first study of\nfinite-density QCD with Wilson-type quarks and the first calculation of the\nequation of state with 2+1 flavors of Wilson-type quarks. We present results of\nthese studies and discuss perspectives towards a clarification of the\nproperties of 2+1 flavor QCD at the physical point, at finite temperatures and\ndensities."
    },
    {
        "anchor": "Angular momentum content of the $\u03c1(1450)$ from chiral lattice\n  fermions: We identify the chiral and angular momentum content of the leading\nquark-antiquark Fock component for the $\\rho(770)$ and $\\rho(1450)$ mesons\nusing a two-flavor lattice simulation with dynamical Overlap Dirac fermions. We\nextract this information from the overlap factors of two interpolating fields\nwith different chiral structure and from the unitary transformation between\nchiral and angular momentum basis. For the chiral content of the mesons we find\nthat the $\\rho(770)$ slightly favors the $(1,0)\\oplus(0,1)$ chiral\nrepresentation and the $\\rho(1450)$ slightly favors the $(1/2,1/2)_b$ chiral\nrepresentation. In the angular momentum basis the $\\rho(770)$ is then a $^3S_1$\nstate, in accordance with the quark model. The $\\rho(1450)$ is a $^3D_1$ state,\nshowing that the quark model wrongly assumes the $\\rho(1450)$ to be a radial\nexcitation of the $\\rho(770)$.",
        "positive": "On the Critical Flavor Number in the 2+1$d$ Thirring Model: The Thirring model in 2+1 spacetime dimensions, in which $N$ flavors of\nrelativistic fermion interact via a contact interaction between conserved\nfermion currents, is studied using lattice field theory simulations employing\ndomain wall fermions, which furnish the correct U(2N) global symmetry in the\nlimit that the wall separation $L_s\\to\\infty$. Attention is focussed on the\nissue of spontaneous symmetry breakdown via a non-vanishing fermion bilinear\ncondensate $\\langle\\bar\\psi\\psi\\rangle\\not=0$. Results from quenched\nsimulations are presented demonstrating that a non-zero condensate does indeed\nform over a range of couplings, provided simulation results are first\nextrapolated to the $L_s\\to\\infty$ limit. Next, results from simulations with\n$N=1$ using an RHMC algorithm demonstrate that U(2) symmetry is unbroken at\nweak coupling but plausibly broken at strong coupling. Correlators of mesons\nwith spin zero are consistent with the Goldstone spectrum expected from\nU(2)$\\to$U(1)$\\otimes$U(1). We infer the existence of a symmetry-breaking phase\ntransition at some finite coupling, and combine this with previous simulation\nresults to deduce that the critical number of flavors for the existence of a\nquantum critical point in the Thirring model satisfies $0<N_c<2$, with strong\nevidence that in fact $N_c>1$."
    },
    {
        "anchor": "Dynamics of Clusters in Two-dimensional Potts Model: Dynamical behavior of the clusters during relaxation is studied in\ntwo-dimensional Potts model using cluster algorithm. Average cluster size and\ncluster formation velocity are calculated on two different lattice sizes for\ndifferent number of states during initial stages of the Monte Carlo simulation.\nDependence of these quantities on the order of the transition provides an\nefficient method to study nature of the phase transitions occuring in similar\nmodels.",
        "positive": "Lattice QCD with purely imaginary sources at zero and non-zero\n  temperature: We discuss various aspects and recent progress concerning lattice QCD studies\nin the presence of external sources. We focus, in particular, on issues\nregarding QCD with non-zero imaginary chemical potentials or with a\n$\\theta$-term, and on the properties of strongly interacting matter in the\npresence of electromagnetic background fields."
    },
    {
        "anchor": "$B_s \\to K \\ell \u03bd$ form factors from lattice QCD: We report the first lattice QCD calculation of the form factors for the\nstandard model tree-level decay $B_s\\to K \\ell\\nu$. In combination with future\nmeasurement, this calculation will provide an alternative exclusive\nsemileptonic determination of $|V_{ub}|$. We compare our results with previous\nmodel calculations, make predictions for differential decay rates and branching\nfractions, and predict the ratio of differential branching fractions between\n$B_s\\to K\\tau\\nu$ and $B_s\\to K\\mu\\nu$. We also present standard model\npredictions for differential decay rate forward-backward asymmetries,\npolarization fractions, and calculate potentially useful ratios of $B_s\\to K$\nform factors with those of the fictitious $B_s\\to\\eta_s$ decay. Our lattice\nsimulations utilize NRQCD $b$ and HISQ light quarks on a subset of the MILC\nCollaboration's $2+1$ asqtad gauge configurations, including two lattice\nspacings and a range of light quark masses.",
        "positive": "Excitations of strange bottom baryons: The ground state and first excited state masses of Omega(b) and Omega(bb)\nbaryons are calculated in lattice QCD using dynamical 2+1 flavour gauge fields.\nA set of baryon operators employing different combinations of smeared quark\nfields was used in the framework of the variational method. Results for radial\nexcitation energies were confirmed by carrying out a supplementary\nmultiexponential fitting analysis. Comparison is made with quark model\ncalculations."
    },
    {
        "anchor": "Optimizing Shift Selection in Multilevel Monte Carlo for Disconnected\n  Diagrams in Lattice QCD: The calculation of disconnected diagram contributions to physical signals is\na computationally expensive task in Lattice QCD. To extract the physical\nsignal, the trace of the inverse Lattice Dirac operator, a large sparse matrix,\nmust be stochastically estimated. Because the variance of the stochastic\nestimator is typically large, variance reduction techniques must be employed.\nMultilevel Monte Carlo (MLMC) methods reduce the variance of the trace\nestimator by utilizing a telescoping sequence of estimators. Frequency\nSplitting is one such method that uses a sequence of inverses of shifted\noperators to estimate the trace of the inverse lattice Dirac operator, however\nthere is no a priori way to select the shifts that minimize the cost of the\nmultilevel trace estimation. In this article, we present a sampling and\ninterpolation scheme that is able to predict the variances associated with\nFrequency Splitting under displacements of the underlying space time lattice.\nThe interpolation scheme is able to predict the variances to high accuracy and\ntherefore choose shifts that correspond to an approximate minimum of the cost\nfor the trace estimation. We show that Frequency Splitting with the chosen\nshifts displays significant speedups over multigrid deflation, and that these\nshifts can be used for multiple configurations within the same ensemble with no\npenalty to performance.",
        "positive": "The spectrum of GUT-like gauge-scalar models: Past lattice simulations tentatively suggested that the spectrum of\nobservable particles in BSM theories is qualitatively different than\nperturbatively expected. The discrepancy can be traced back to nontrivial\nfield-theoretical effects arising from the requirement of gauge invariance. A\nperturbative but gauge-invariant approach working directly with bound states\n(as proposed by Fr\\\"ohlich, Morchio and Strocchi) could provide a solution, by\nallowing composite-state effects to be treated within a perturbative framework.\nWe consider a toy GUT-like theory -- SU(3) Yang-Mills coupled to a scalar\n`Higgs' in the fundamental representation -- and expand on previous work by\nproviding the most comprehensive spectroscopy to date, including all channels\nup to spin 2. Our results strongly support the general conclusion that the\nelementary spectrum is not an adequate proxy for the low-energy spectrum of a\nGUT, and also suggest a possible analytical approach to BSM model-building via\nthe Fr\\\"ohlich-Morchio-Strocchi approach."
    },
    {
        "anchor": "How to compute Green's Functions for entire Mass Trajectories within\n  Krylov Solvers: The availability of efficient Krylov subspace solvers play a vital role for\nthe solution of a variety of numerical problems in computational science. Here\nwe consider lattice field theory. We present a new general numerical method to\ncompute many Green's functions for complex non-singular matrices within one\niteration process. Our procedure applies to matrices of structure $A=D-m$, with\n$m$ proportional to the unit matrix, and can be integrated within any Krylov\nsubspace solver. We can compute the derivatives $x^{(n)}$ of the solution\nvector $x$ with respect to the parameter $m$ and construct the Taylor expansion\nof $x$ around $m$. We demonstrate the advantages of our method using a minimal\nresidual solver. Here the procedure requires $1$ intermediate vector for each\nGreen's function to compute. As real life example, we determine a mass\ntrajectory of the Wilson fermion matrix for lattice QCD. Here we find that we\ncan obtain Green's functions at all masses $\\geq m$ at the price of one\ninversion at mass $m$.",
        "positive": "Lattice calculation of the hadronic leading order contribution to the\n  muon $g-2$: The persistent discrepancy of about 3.5 standard deviations between the\nexperimental measurement and the Standard Model prediction for the muon\nanomalous magnetic moment, $a_\\mu$, is one of the most promising hints for the\npossible existence of new physics. Here we report on our lattice QCD\ncalculation of the hadronic vacuum polarisation contribution $a_\\mu^{\\rm hvp}$,\nbased on gauge ensembles with $N_f=2+1$ flavours of O($a$) improved Wilson\nquarks. We address the conceptual and numerical challenges that one encounters\nalong the way to a sub-percent determination of the hadronic vacuum\npolarisation contribution. The current status of lattice calculations of\n$a_\\mu^{\\rm hvp}$ is presented by performing a detailed comparison with the\nresults from other groups."
    },
    {
        "anchor": "From tensors to qubits: We discuss recent progress in Tensor Lattice Field Theory and economical,\nsymmetry preserving, truncations suitable for quantum computations or\nsimulations. We focus on spin and gauge models with continuous Abelian\nsymmetries such as the Abelian Higgs model and emphasize noise-robust\nimplementations of Gauss's law. We discuss recent progress concerning the\ncomparison between field digitizations and character expansions, symmetry\nbreaking in tensor language, wave-packet preparation and possible new\nimplementations of Abelian models using Rydberg atoms.",
        "positive": "Toward Quantum Simulations of $\\mathbb{Z}_2$ Gauge Theory Without State\n  Preparation: Preparing strongly-coupled particle states on quantum computers requires\nlarge resources. In this work, we show how classical sampling coupled with\nprojection operators can be used to compute Minkowski matrix elements without\nexplicitly preparing these states on the quantum computer. We demonstrate this\nfor the 2+1d $\\mathbb{Z}_2$ lattice gauge theory on small lattices with a\nquantum simulator."
    },
    {
        "anchor": "Dynamical Quark Effects in QCD: We discuss latest results of lattice QCD simulations with dynamical fermions.\nSpecial emphasis is paid to the subjects of the static quark potential, the\nlight hadron spectrum, $\\Upsilon$ spectrum, and the pion-nucleon-sigma term.",
        "positive": "Recent Progress on the QCD Phase Diagram: Recent progress and the latest results on the bulk thermodynamic properties\nof QCD matter from lattice are reviewed. In particular, I will stress upon the\nfact that lattice techniques are now entering into precision era where they can\nprovide us with new insights on even the microscopic degrees of freedom in\ndifferent phases of QCD. I will discuss some instances, from the recent studies\nof topological fluctuations and screening masses. The progress towards\nunderstanding the effects of anomalous $U_A(1)$ symmetry on the chiral\ncrossover transition and transport properties of QCD matter will also be\ndiscussed."
    },
    {
        "anchor": "pi+ pi+, K+ K+ and B B Interactions: The most recent calculations of pi+ pi+ and K+ K+ scattering by the NPLQCD\ncollaboration using domain-wall valence quarks on staggered MILC configurations\nare presented. In addition, a quenched calculation of the potentials between\ntwo B-mesons is discussed.",
        "positive": "Exotic phases of finite temperature SU(N) gauge theories with massive\n  fermions: F, Adj, A/S: The phase diagrams at high temperature of SU(N) gauge theories with massive\nfermions are calculated by numerically minimizing the one-loop effective\npotential. We consider fermions in the Fundamental (F), Adjoint (Adj),\nAntisymmetric (AS), and Symmetric (S) representations, for N from 3 to 9, with\nperiodic and antiperiodic boundary conditions applied. For one flavour of AS/S\n(Dirac) fermion with periodic boundary conditions the C-breaking phase is\nfavoured perturbatively for all values of the fermion mass. In the case of one\nflavour of adjoint Majorana fermion, and periodic boundary conditons, the\ndeconfined phase is favoured for any fermion mass. For one or more adjoint\nDirac fermion (two or more Majorana fermions) we find partially-confining\nphases as well as new phases with unusual properties. Our results for SU(3) and\nSU(4) are consistent with our lattice simulations of a related model."
    },
    {
        "anchor": "JLQCD IroIro++ lattice code on BG/Q: We describe our experience on the multipurpose C++ code IroIro++ designed for\nJLQCD to run on the BG/Q installation at KEK. We discuss some details on the\nperformance improvements specific for the IBM Blue Gene Q.",
        "positive": "Meson Mass Decomposition: Hadron masses can be decomposed as a sum of components which are defined\nthrough hadronic matrix elements of QCD operators. The components consist of\nthe quark mass term, the quark energy term, the glue energy term and the trace\nanomaly term. We calculate these components of mesons with lattice QCD for the\nfirst time. The calculation is carried out with overlap fermion on $2+1$ flavor\ndomain-wall fermion gauge configurations. We confirm that $\\sim 50\\%$ of the\nlight pion mass comes from the quark mass and $\\sim 10\\%$ comes from the quark\nenergy, whereas, the contributions are found to be the other way around for the\n$\\rho$ mass. The combined glue components contribute $\\sim 40 - 50\\%$ for both\nmesons. It is interesting to observe that the quark mass contribution to the\nmass of the vector meson is almost linear in quark mass over a large quark mass\nregion below the charm quark mass. For heavy mesons, the quark mass term\ndominates the masses, while the contribution from the glue components is about\n$400\\sim500$ MeV for the heavy pseudoscalar and vector mesons. The charmonium\nhyperfine splitting is found to be dominated by the quark energy term which is\nconsistent with the quark potential model."
    },
    {
        "anchor": "Probing the photon emissivity of the quark-gluon plasma without an\n  inverse problem in lattice QCD: The thermal photon emissivity of the quark-gluon plasma is determined by the\nin-medium spectral function of the electromagnetic current at lightlike\nkinematics, $\\sigma(\\omega)$. In this work, we present the first lattice QCD\nresults on moments of $\\sigma(\\omega)/\\omega$, defined by the weight function\n$1/(\\omega^2+ (2\\pi T n)^2)$, $n\\in\\mathbb{Z}$ and computed without\nencountering an inverse problem. We employ two dynamical flavours of\nO($a$)-improved Wilson fermions at a temperature $T\\approx 250\\;$MeV and\nperform the continuum limit. We compare our results for the first two moments\nto those obtained dispersively by integrating over the spectral function\ncomputed at weak coupling by Arnold, Moore and Yaffe.",
        "positive": "Complex Langevin boundary terms in full QCD: Lattice simulations of non-zero density QCD introduce the so-called sign\nproblem (complex or negative probabilities), which invalidates importance\nsampling methods. To circumvent this, we use the Complex Langevin Equation\n(CLE), to measure the boundary terms and then compare these results with the\nones gotten from reweighting, confirming the expectations from previous\nstudies. We also investigate boundary terms in simulations using CLE with\ndynamic stabilization and compare this, to results calculated with reweighting."
    },
    {
        "anchor": "Replica evolution of classical field in 4+1 dimensional spacetime toward\n  real time dynamics of quantum field: Real-time evolution of replicas of classical field is proposed as an\napproximate simulator of real-time quantum field dynamics at finite\ntemperatures. We consider $N$ classical field configurations dubbed as replicas\nwhich interact with each other via the $\\tau$-derivative terms and evolve with\nthe classical equation of motion. The partition function of replicas is found\nto be proportional to that of quantum field in the imaginary time formalism. As\nthe replica index $\\tau$ can be regarded as the imaginary time index, the\nreplica evolution is technically the same as the molecular dynamics part of the\nhybrid Monte-Carlo sampling and the replica configurations should reproduce the\ncorrect quantum equilibrium distribution after the long-time evolution. At the\nsame time, evolution of the replica-index average of field variables is\ndescribed by the classical equation of motion when the fluctuations are small.\nIn order to examine the real-time propagation properties of replicas, we first\ndiscuss replica evolution in quantum mechanics. Statistical averages of\nobservables are precisely obtained by the initial condition average of replica\nevolution, and the time evolution of the unequal-time correlation function,\n$\\langle x(t) x(t')\\rangle$, in a harmonic oscillator is also described well by\nthe replica evolution in the range $T/\\omega > 0.5$. Next, we examine the\nstatistical and dynamical properties of the $\\phi^4$ theory in the 4+1\ndimensional spacetime, which contains three spatial, one replica index or the\nimaginary time, and one real-time. We note that the Rayleigh-Jeans divergence\ncan be removed in replica evolution with $N \\geq 2$ when the mass counterterm\nis taken into account. We also find that the thermal mass obtained from the\nunequal-time correlation function at zero momentum grows as a function of the\ncoupling as in the perturbative estimate in the small coupling region.",
        "positive": "Stochastic Estimation with $Z_2$ Noise: We introduce a $Z_2$ noise for the stochastic estimation of matrix inversion\nand discuss its superiority over other noises including the Gaussian noise.\nThis algorithm is applied to the calculation of quark loops in lattice quantum\nchromodynamics that involves diagonal and off-diagonal traces of the inverse\nmatrix. We will point out its usefulness in its applications to estimating\ndeterminants, eigenvalues, and eigenvectors, as well as its limitations based\non the structure of the inverse matrix."
    },
    {
        "anchor": "Transverse momentum-dependent parton distributions for longitudinally\n  polarized nucleons from domain wall fermion calculations at the physical pion\n  mass: Previous Lattice QCD calculations of nucleon transverse momentum-dependent\nparton distributions (TMDs) focused on the case of transversely polarized\nnucleons, and thus did not encompass two leading-twist TMDs associated with\nlongitudinal polarization, namely, the helicity TMD and the worm-gear TMD\ncorresponding to transversely polarized quarks in a longitudinally polarized\nnucleon. Based on a definition of TMDs via hadronic matrix elements of quark\nbilocal operators containing staple-shaped gauge connections, TMD observables\ncharacterizing the aforementioned two TMDs are evaluated, utilizing an\nRBC/UKQCD domain wall fermion ensemble at the physical pion mass.",
        "positive": "Classifying the Phases of Gauge Theories by Spectral Density of Probing\n  Chiral Quarks: We describe our recent proposal that distinct phases of gauge theories with\nfundamental quarks translate into specific types of low-energy behavior in\nDirac spectral density. The resulting scenario is built around new evidence\nsubstantiating the existence of a phase characterized by bimodal (anomalous)\ndensity, and corresponding to deconfined dynamics with broken valence chiral\nsymmetry. We argue that such anomalous phase occurs quite generically in these\ntheories, including in \"real world\" QCD above the crossover temperature, and in\nzero-temperature systems with many light flavors."
    },
    {
        "anchor": "Lattice gauge-fixing for generic covariant gauges: We propose a method which allows the generalization of the Landau lattice\ngauge-fixing procedure to generic covariant gauges. We report preliminary\nnumerical results showing how the procedure works for $SU(2)$ and $SU(3)$. We\nalso report numerical results showing that the contribution of finite\nlattice-spacing effects and/or spurious copies are relevant in the lattice\ngauge-fixing procedure.",
        "positive": "Chiral symmetry restoration in QCD with many flavours: We discuss the phases of QCD in the parameter space spanned by the number of\nlight flavours and the temperature with respect to the realisation of chiral\nand conformal symmetries. The intriguing interplay of these symmetries is best\nstudied by means of lattice simulations, and some selected results from our\nrecent work are presented here."
    },
    {
        "anchor": "Effective mesonic theory for the 't Hooft model on the lattice: We apply to a lattice version of the 't~Hooft model, QCD in two space-time\ndimensions for large number of colours, a method recently proposed to obtain an\neffective mesonic action starting from the fundamental, fermionic one. The idea\nis to pass from a canonical, operatorial representation, where the low-energy\nstates have a direct physical interpretation in terms of a Bogoliubov vacuum\nand its corresponding quasiparticle excitations, to a functional, path integral\nrepresentation, via the formalism of the transfer matrix. In this way we obtain\na lattice effective theory for mesons in a self-consistent setting. We also\nverify that well-known results from other different approaches are reproduced\nin the continuum limit.",
        "positive": "Infrared physics of the $\\mathrm{SU}(2)$ Georgi-Glashow crossover\n  transition: We perform a lattice study of the phase transition in the $\\mathrm{SU}(2)$\nGeorgi-Glashow model in three dimensions, where the gauge symmetry is broken to\n$\\mathrm{U}(1)$ by the Higgs mechanism and a photon-like state appears. Due to\ncondensation of monopoles the photon acquires a mass, which depends on the\nnumber density of the monopoles. We show that the monopole density can be\nrenormalised on the lattice using gradient flow. Our preliminary results\nsuggest that Polyakov's semiclassical relation between the photon mass and the\nrenormalised monopole density is valid also at the nonperturbative level."
    },
    {
        "anchor": "Lattice results on dibaryons and baryon--baryon interactions: We present the recent study on dibaryons at the almost physical pion mass in\nlattice QCD by the HAL QCD potential method.",
        "positive": "Three dimensional four-fermion models - A Monte Carlo study: We present results from numerical simulations of three different 3d\nfour-fermion models that exhibit Z_2, U(1), and SU(2) x SU(2) chiral\nsymmetries, respectively. We performed the simulations by using the hybrid\nMonte Carlo algorithm. We employed finite size scaling methods on lattices\nranging from 8^3 to 40^3 to study the properties of the second order chiral\nphase transition in each model. The corresponding critical coupling defines an\nultraviolet fixed point of the renormalization group. In our high precision\nsimulations, we detected next-to-leading order corrections for various critical\nexponents and we found them to be in good agreement with existing analytical\nlarge-N_f calculations."
    },
    {
        "anchor": "Overview of external electromagnetism and rotation in lattice QCD: This is an introductory review of lattice QCD with external fields. The study\nof external magnetic fields is one of the greatest achievements in modern\nlattice QCD. Large-scale simulations and detailed analyses have revealed\nintriguing properties of QCD in the magnetic fields. The study of external\nelectric fields is more challenging because of a technical difficulty. We\noverview the successes and challenges of the lattice simulations with the\nelectromagnetic fields. We also introduce a newly developing field, the lattice\nsimulation of rotating QCD matters.",
        "positive": "QCD Thermodynamics: Lattice Results confront Models: We show that lattice results on four flavor QCD at nonzero temperature and\nbaryon density compare well with the hadron resonance gas model up to T approx.\n0.95 Tc, and approach a free field behaviour with a reduced effective number of\nflavor for T \\ge 1.5 Tc. Chiral symmetry and confinement are interrelated, and\nwe note analogies between the critical line of QCD and that of simple models\nwith the same global symmetries."
    },
    {
        "anchor": "Finite Size Scaling and ``perfect'' actions: the three dimensional Ising\n  model: Using Finite-Size Scaling techniques, we numerically show that the first\nirrelevant operator of the lattice $\\lambda\\phi^4$ theory in three dimensions\nis (within errors) completely decoupled at $\\lambda=1.0$. This interesting\nresult also holds in the Thermodynamical Limit, where the renormalized coupling\nconstant shows an extraordinary reduction of the scaling-corrections when\ncompared with the Ising model. It is argued that Finite-Size Scaling analysis\ncan be a competitive method for finding improved actions.",
        "positive": "Possible Consequences of Conjectural Periodicity of Spectrum of Lattice\n  Dirac Operator: Some consequences which follow from the periodicity assumption for spectral\ndensity of Wilson--Dirac operator are studied. Such an assumption allows to\nobtain simple representations for quark propagator, which reveals an important\nrole of $m\\leftrightarrow -m$ symmetry. It is argued that this symmetry is\nrestored when the mirror fermion mass $m_r$ tended to infinity. The constrains\non zero modes of Wilson--Dirac operator in a toy model approximation are also\ndiscussed."
    },
    {
        "anchor": "Topology and the axial anomaly in abelian lattice gauge theories: The axial anomaly in abelian lattice gauge theories is shown to be equal to a\nsimple quadratic expression in the gauge field tensor plus a removable\ndivergence term if the lattice Dirac operator satisfies the Ginsparg-Wilson\nrelation. The theorem is a consequence of the locality, the gauge invariance\nand the topological nature of the anomaly and does not refer to any other\nproperties of the lattice theory.",
        "positive": "Matching issue in quasi parton distribution approach: In recent years, the quasi parton distribution has been introduced for\nextracting the parton distribution functions from lattice QCD simulations. The\nquasi and standard distribution share the same perturbative collinear\nsingularity and the renormalized quasi distribution can be factorized into the\nstandard distribution with a perturbative matching factor. The quasi parton\ndistribution is known to have power-law UV divergences, which do not exist in\nthe standard distribution. We discuss in this talk the nonperturbative\nrenormalization scheme for the power divergence. We also demonstrate the\nperturbative matching of the quasi quark distribution between continuum and\nlattice at the one-loop."
    },
    {
        "anchor": "Finite density QCD via imaginary chemical potential: We study QCD at nonzero temperature and baryon density in the framework of\nthe analytic continuation from imaginary chemical potential. We carry out\nsimulations of QCD with four flavor of staggered fermions, and reconstruct the\nphase diagram in the temperature-imaginary \\mu plane. We consider ans\\\"atze for\nthe analytic continuation of the critical line and other observables motivated\nboth by theoretical considerations and mean field calculations in four fermion\nmodels and random matrix theory. We determine the critical line, and the\nanalytic continuation of the chiral condensate, up to \\mu_B approx. 500 MeV.\nThe results are in qualitative agreement with the predictions of model field\ntheories, and consistent with a first order chiral transition. The correlation\nbetween the chiral transition and the deconfinement transition observed at\n\\mu=0 persists at nonzero density.",
        "positive": "$|V_{us}|$ from $K$ decays in theory: Leptonic and semileptonic kaon decays represent till now the golden modes for\nthe extraction of the Cabibbo angle from experiments, provided the relevant\nhadronic quantities, namely the ratio of the kaon and pion leptonic decay\nconstants, $f_K / f_\\pi$, and the semileptonic vector form factor at zero\nfour-momentum transfer, $f_+(0)$, are computed accurately from QCD. In the last\nyears, using large-scale lattice QCD simulations, the determination of both\n$f_K / f_\\pi$ and $f_+(0)$ has reached an impressive level of precision\n($\\approx 0.3 \\%$), which is expected to be further improved in the near\nfuture. However, at a permille level of precision both electromagnetic and\nstrong isospin-breaking effects cannot be neglected anymore. In this\ncontribution a new lattice strategy aiming at determining QCD+QED effects in\nthe inclusive leptonic decay rates of charged pseudoscalar mesons is briefly\nillustrated, and the preliminary results obtained in the case of $\\pi_{\\ell 2}$\nand $K_{\\ell 2}$ decays are presented. As for the semileptonic $K_{\\ell 3}$\ndecays, it is pointed out that the determination of the relevant form factors\nin the full kinematical range covered by the experiments is necessary for a\nmore stringent test of the Standard Model. In this respect the perspectives\nbased on the only existing results from the European Twisted Mass Collaboration\n(ETMC) are quite encouraging."
    },
    {
        "anchor": "Clebsch-Gordan Construction of Lattice Interpolating Fields for Excited\n  Baryons: Large sets of baryon interpolating field operators are developed for use in\nlattice QCD studies of baryons with zero momentum. Operators are classified\naccording to the double-valued irreducible representations of the octahedral\ngroup. At first, three-quark smeared, local operators are constructed for each\nisospin and strangeness and they are classified according to their symmetry\nwith respect to exchange of Dirac indices. Nonlocal baryon operators are\nformulated in a second step as direct products of the spinor structures of\nsmeared, local operators together with gauge-covariant lattice displacements of\none or more of the smeared quark fields. Linear combinations of direct products\nof spinorial and spatial irreducible representations are then formed with\nappropriate Clebsch-Gordan coefficients of the octahedral group. The\nconstruction attempts to maintain maximal overlap with the continuum SU(2)\ngroup in order to provide a physically interpretable basis. Nonlocal operators\nprovide direct couplings to states that have nonzero orbital angular momentum.",
        "positive": "On Existence of Nontrivial Fixed Points in Large $N$ Gauge Theory in\n  More than Four Dimensions: Inspired by a possible relation between large $N$ gauge theory and string\ntheory, we search for nontrivial fixed points in large $N$ gauge theory in more\nthan four dimensions. We study large $N$ gauge theory through Monte Carlo\nsimulation of the twisted Eguchi-Kawai model in six dimensions as well as in\nfour dimensions. The phase diagram of the system with the two coupling\nconstants which correspond to the standard plaquette action and the adjoint\nterm has been explored."
    },
    {
        "anchor": "Neutron in a Strong Magnetic Field: Finite Volume Effects: We investigate the neutron's response to magnetic fields on a torus with the\naid of chiral perturbation theory, and expose effects from non-vanishing\nholonomies. The determination of such effects necessitates non-perturbative\ntreatment of the magnetic field; and, to this end, a strong-field power\ncounting is employed. Using a novel coordinate-space method, we find the\nneutron propagates in a coordinate-dependent effective potential that we obtain\nby integrating out charged pions winding around the torus. Knowledge of these\nfinite volume effects will aid in the extraction of neutron properties from\nlattice QCD computations in external magnetic fields. In particular, we obtain\nfinite volume corrections to the neutron magnetic moment and magnetic\npolarizability. These quantities have not been computed correctly in the\nliterature. In addition to effects from non-vanishing holonomies, finite volume\ncorrections depend on the magnetic flux quantum through an Aharonov-Bohm\neffect. We make a number of observations that demonstrate the importance of\nnon-perturbative effects from strong magnetic fields currently employed in\nlattice QCD calculations. These observations concern neutron physics in both\nfinite and infinite volume.",
        "positive": "Fermion number violation and a two-dimensional Higgs model: The investigation of topological properties of the gauge field in a\ntwo-dimensional Higgs model can help in understanding anomalous fermion number\nviolation."
    },
    {
        "anchor": "Exploring the Phase Diagram of Lattice Quantum Gravity: We present evidence that a nonperturbative model of quantum gravity defined\nvia Euclidean dynamical triangulations contains a region in parameter space\nwith an extended 4-dimensional geometry when a non-trivial measure term is\nincluded in the gravitational path integral. Within our extended region we find\na large scale spectral dimension of D_s = 4.04 +/- 0.26 and a Hausdorff\ndimension that is consistent with D_H = 4 from finite size scaling. We find\nthat the short distance spectral dimension is D_s ~ 3/2, which may resolve the\ntension between asymptotic safety and holographic entropy scaling.",
        "positive": "Evidence of the Schwinger mechanism from lattice QCD: In quantum chromodynamics (QCD), gluons acquire a mass scale through the\naction of the Schwinger mechanism. This mass emerges as a result of the\ndynamical formation of massless bound-states of gluons which manifest as\nlongitudinally coupled poles in the vertices. In this contribution, we show how\nthe presence of these poles can be determined from lattice QCD results for the\npropagators and vertices. The crucial observation that allows this\ndetermination is that the Schwinger mechanism poles induce modifications,\ncalled ``displacements'', to the Ward identities (WIs) relating two- and\nthree-point functions. Importantly, the displacement functions correspond\nprecisely to the Bethe-Salpeter amplitudes of the massless bound-states. We\napply this idea to the case of the three-gluon vertex in pure Yang-Mills SU(3).\nUsing lattice results in the corresponding WI, we find an unequivocal\ndisplacement and show that it is consistent with the prediction based on the\nBethe-Salpeter equation."
    },
    {
        "anchor": "The dyonic picture of topological objects in the deconfined phase: In the deconfinement phase of quenched SU(2) Yang-Mills theory the spectrum\nand localization properties of the eigenmodes of the overlap Dirac operator\nwith antiperiodic boundary conditions are strongly dependent on the sign of the\naverage Polyakov loop, $<L>$. For $<L> > 0$ a gap appears with only few, highly\nlocalized topological zero and near-zero modes separated from the rest of the\nspectrum. Instead of a gap, for $<L> < 0$ a high spectral density of relatively\ndelocalized near-zero modes is observed. In an ensemble of positive $<L>$, the\nsame difference of the spectrum appears under a change of fermionic boundary\nconditions. We argue that this effect and other properties of near-zero modes\ncan be explained through the asymmetric properties and the different abundance\nof dyons and antidyons -- topological objects also known to appear, however in\na symmetric form, in the confinement phase at $T < T_c$ as constituents of\ncalorons with maximally nontrivial holonomy.",
        "positive": "Noncomputability Arising In Dynamical Triangulation Model Of\n  Four-Dimensional Quantum Gravity: Computations in Dynamical Triangulation Models of Four-Dimensional Quantum\nGravity involve weighted averaging over sets of all distinct triangulations of\ncompact four-dimensional manifolds. In order to be able to perform such\ncomputations one needs an algorithm which for any given $N$ and a given compact\nfour-dimensional manifold $M$ constructs all possible triangulations of $M$\nwith $\\leq N$ simplices. Our first result is that such algorithm does not\nexist. Then we discuss recursion-theoretic limitations of any algorithm\ndesigned to perform approximate calculations of sums over all possible\ntriangulations of a compact four-dimensional manifold."
    },
    {
        "anchor": "Nucleon Properties at Finite Volume: the Epsilon Prime Regime: We study the properties of the nucleon in highly asymmetric volumes where the\nspatial dimensions are small but the time dimension is large in comparison to\nthe inverse pion mass. To facilitate power-counting at the level of Feynman\ndiagrams, we introduce $\\epsilon^\\prime$-power-counting which is a special case\nof Leutwyler's $\\delta$-power-counting. Pion zero-modes enter the\n$\\epsilon^\\prime$-counting perturbatively, in contrast to both the $\\epsilon$-\nand $\\delta$-power-countings, since $m_q < q\\bar{q}> V$ remains large. However,\nthese modes are enhanced over those with non-zero momenta and enter at lower\norders in the $\\epsilon^\\prime$-expansion than they would in large volume\nchiral perturbation theory. We discuss an application of\n$\\epsilon^\\prime$-counting by determining the nucleon mass, magnetic moment and\naxial matrix element at the first nontrivial order in the\n$\\epsilon^\\prime$-expansion.",
        "positive": "Matrix elements of the electromagnetic operator between kaon and pion\n  states: We compute the matrix elements of the electromagnetic (EM) operator between\nkaon and pion states, using lattice QCD with maximally twisted-mass fermions\nand two flavors of dynamical quarks (Nf = 2). The EM operator is renormalized\nnon-perturbatively in the RI'/MOM scheme and our simulations cover pion masses\nas light as 260 MeV and three values of the lattice spacing, ranging from ~\n0.07 up to ~ 0.1 fm. At the physical point our preliminary result for the K ->\npion tensor form factor at zero-momentum transfer is fT[K\\pi](0) =\n0.42(2_stat), which differs significantly from the old quenched result\nfT[K\\pi](0) = 0.78(6) obtained by the SPQcdR Collaboration with pion masses\nabove 500 MeV. We investigate the source of this difference and conclude that\nit is mainly related to the chiral extrapolation of the quenched data. For the\ncase of the tensor charge of the pion we obtain the preliminary value\nfT[\\pi\\pi](0) = 0.200(14_stat), which can be compared with the result\nfT[\\pi\\pi](0) = 0.216(34) obtained at Nf = 2 by the QCDSF Collaboration using\nhigher pion masses."
    },
    {
        "anchor": "Topology in QCD with 4 flavours of dynamical fermions: We study the topological properties of full QCD with four flavours of\ndynamical staggered fermions. In particular the topological susceptibility is\nmeasured and the problem of the determination of its first derivative is\ndiscussed.",
        "positive": "Localization of Dirac Fermions in Finite-Temperature Gauge Theory: It is by now well established that Dirac fermions coupled to non-Abelian\ngauge theories can undergo an Anderson-type localization transition. This\ntransition affects eigenmodes in the lowest part of the Dirac spectrum, the\nones most relevant to the low-energy physics of these models. Here we review\nseveral aspects of this phenomenon, mostly using the tools of lattice gauge\ntheory. In particular, we discuss how the transition is related to the\nfinite-temperature transitions leading to the deconfinement of fermions, as\nwell as to the restoration of chiral symmetry that is spontaneously broken at\nlow temperature. Other topics we touch upon are the universality of the\ntransition, and its connection to topological excitations (instantons) of the\ngauge field and the associated fermionic zero modes. While the main focus is on\nQuantum Chromodynamics, we also discuss how the localization transition appears\nin other related models with different fermionic contents (including the\nquenched approximation), gauge groups, and in different space-time dimensions.\nFinally, we offer some speculations about the physical relevance of the\nlocalization transition in these models."
    },
    {
        "anchor": "Review of Lattice QCD Studies of Hadronic Vacuum Polarization\n  Contribution to Muon g-2: Lattice QCD (LQCD) studies for the hadron vacuum polarization (HVP) and its\ncontribution to the muon anomalous magnetic moment (muon g-2) are reviewed.\nThere currently exists more than 3-sigma deviations in the muon g-2 between the\nBNL experiment with 0.5 ppm precision and the Standard Model (SM) predictions,\nwhere the latter relies on the QCD dispersion relation for the HVP. The LQCD\nprovides an independent crosscheck of the dispersive approaches and important\nindications for assessing the SM prediction with measurements at\nongoing/forthcoming experiments at Fermilab/J-PARC (0.14/0.1 ppm precision).\nThe LQCD has made significant progress, in particular, in the long distance and\nfinite volume control, continuum extrapolations, and QED and strong isospin\nbreaking (SIB) corrections. In the recently published papers, two LQCD\nestimates for the HVP muon g-2 are consistent with No New Physics while the\nother three are not. The tension solely originates to the light-quark connected\ncontributions and indicates some under-estimated systematics in the large\ndistance control. The strange and charm connected contributions as well as the\ndisconnected contributions are consistent among all LQCD groups and determined\nprecisely. The total error is at a few percent level. It is still premature by\nthe LQCD to confirm or infirm the deviation between the experiments and the SM\npredictions. If the LQCD is combined with the dispersive method, the HVP muon\ng-2 is predicted with 0.4% uncertainty, which is close upon the target\nprecision required by the Fermilab/J-PARC experiments. Continuous and\nconsiderable improvements are work in progress, and there are good prospects\nthat the target precision will get achieved within the next few years.",
        "positive": "Weak universality induced by $Q=\\pm 2e$ charges at the deconfinement\n  transition of a (2+1)-d $U(1)$ lattice gauge theory: Matter-free lattice gauge theories (LGTs) provide an ideal setting to\nunderstand confinement to deconfinement transitions at finite temperatures,\nwhich is typically due to the spontaneous breakdown (at large temperatures) of\nthe centre symmetry associated with the gauge group. Close to the transition,\nthe relevant degrees of freedom (Polyakov loop) transform under these centre\nsymmetries, and the effective theory only depends on the Polyakov loop and its\nfluctuations. As shown first by Svetitsky and Yaffe, and subsequently verified\nnumerically, for the $U(1)$ LGT in $(2+1)$-d the transition is in the 2-d XY\nuniversality class, while for the $Z_2$ LGT, it is in the 2-d Ising\nuniversality class. We extend this classic scenario by adding higher charged\nmatter fields, and show that the notion of universality is generalized such\nthat the critical exponents $\\gamma, \\nu$ can change continuously as a coupling\nis varied, while their ratio is fixed to the 2-d Ising value. While such weak\nuniversality is well-known for spin models, we demonstrate this for LGTs for\nthe first time. Using an efficient cluster algorithm, we show that the finite\ntemperature phase transition of the $U(1)$ quantum link LGT in the spin\n$S=\\frac{1}{2}$ representation is in the 2-d XY universality class, as\nexpected. On the addition of $Q = \\pm 2e$ charges distributed thermally, we\ndemonstrate the occurrence of weak universality."
    },
    {
        "anchor": "Numerical Evidence for Fractional Topological Objects in SU(3) Gauge\n  Theory: The continued development of models which propose the existence of fractional\ntopological objects in the Yang-Mills vacuum has called for a quantitative\nmethod to study the topological structure of SU($N$) gauge theory. We present\nan original numerical algorithm which can identify distinct topological objects\nin the nontrivial ground-state fields and approximate the net charge contained\nwithin them. This analysis is performed for SU(3) colour at a range of\ntemperatures crossing the deconfinement phase transition, allowing for an\nassessment of how the topological structure evolves with temperature. We find a\npromising consistency with the instanton-dyon model for the structure of the\nQCD vacuum at finite temperature. Several other quantities, such as object\ndensity and radial size, are also analysed to elicit a further understanding of\nthe fundamental structure of ground-state gluon fields.",
        "positive": "Mass anomalous dimension from large N twisted volume reduction: In this work we consider the SU(N) gauge theory with two Dirac fermions in\nthe adjoint representation, in the limit of large N. Taking advantage of large\nN twisted volume reduction we do this on a single site lattice, but we should\nstill get infinite-volume physics in the large N limit. We describe our\nprogress in extracting the mass anomalous dimension from the eigenvalue\ndistribution of the adjoint Dirac operator, using data for N up to 289."
    },
    {
        "anchor": "Computing Masses from Effective Transfer Matrices: We study the use of effective transfer matrices for the numerical computation\nof masses (or correlation lengths) in lattice spin models. The effective\ntransfer matrix has a strongly reduced number of components. Its definition is\nmotivated by a renormalization group transformation of the full model onto a\n1-dimensional spin model. The matrix elements of the effective transfer matrix\ncan be determined by Monte Carlo simulation. We show that the mass gap can be\nrecovered exactly from the spectrum of the effective transfer matrix. As a\nfirst step towards application we performed a Monte Carlo study for the\n2-dimensional Ising model. For the simulations in the broken phase we employed\na multimagnetical demon algorithm. The results for the tunnelling correlation\nlength are particularly encouraging.",
        "positive": "Conformal finite size scaling of twelve fermion flavors: Extended simulation results and their analysis are reported in a strongly\ncoupled gauge theory with twelve fermion flavors in the fundamental SU(3) color\nrepresentation. The conformality of the model is probed using mass deformed\nconformal finite size scaling (FSS) theory driven by the fermion mass anomalous\ndimension. Two independent conformal FSS fitting procedures are used in the\nanalysis. The first one deploys physics motivated scaling functions,\ncomplemented by a second fitting procedure with spline based general B-forms\nfor the scaling functions. The results at fixed gauge coupling show unresolved\nproblems with the conformal hypothesis."
    },
    {
        "anchor": "Improvement of heavy-heavy and heavy-light currents with the\n  Oktay-Kronfeld action: The CKM matrix elements $V_{cb}$ and $V_{ub}$ can be obtained by combining\ndata from the experiments with lattice QCD results for the semi-leptonic form\nfactors for the $\\bar{B} \\to D^\\ast \\ell \\bar{\\nu}$ and $\\bar{B} \\to \\pi \\ell\n\\bar{\\nu}$ decays.\n  It is highly desirable to use the Oktay-Kronfeld (OK) action for the form\nfactor calculation on the lattice, since the OK action is designed to reduce\nthe heavy quark discretization error down to the $\\mathcal{O}(\\lambda^4)$ level\nin the power counting rules of the heavy quark effective theory (HQET).\n  Here, we present a matching calculation to improve heavy-heavy and\nheavy-light currents up to the $\\lambda^3$ order in HQET, the same level of\nimprovement as the OK action. Our final results for the improved currents are\nbeing used in a lattice QCD calculation of the semi-leptonic form factors for\nthe $\\bar{B} \\to D^\\ast \\ell \\bar{\\nu}$ and $\\bar{B} \\to D \\ell \\bar{\\nu}$\ndecays.",
        "positive": "Towards the application of the Maximum Entropy Method to finite\n  temperature Upsilon Spectroscopy: According to the Narnhofer Thirring Theorem interacting systems at finite\ntemperature cannot be described by particles with a sharp dispersion law. It is\ntherefore mandatory to develop new methods to extract particle masses at finite\ntemperature. The Maximum Entropy method offers a path to obtain the spectral\nfunction of a particle correlation function directly. We have implemented the\nmethod and tested it with zero temperature Upsilon correlation functions\nobtained from an NRQCD simulation. Results for different smearing functions are\ndiscussed."
    },
    {
        "anchor": "Non-perturbative aspects in a weakly interacting Higgs sector: Just like the weakly interacting QED can support non-perturbative phenomena,\nlike atoms, so can the weak and Higgs interactions. Especially, there are\nstrong field-theoretical arguments that only bound states can be the\n(quasi-)asymptotic physical degrees of freedom of this sector. After a brief\nreview of these arguments, the 2-point, 3-point and 4-point correlation\nfunctions of the Higgs-W system are determined using lattice gauge theory. The\nresults support a conjectured duality between elementary states and bound\nstates for weak Higgs self-interactions. This leads to relations between the\nbound states and the experimentally observed particles. Interestingly, these\nmay yield pseudo-scalar admixtures at the Higgs energy, and possibly a faint\nstandard-model signal in the channel where a Kaluza-Klein graviton would be\nexpected.",
        "positive": "Non-perturbative renormalization of the $\u0394S=2$ operator and the\n  heavy-light axial current: We apply a recently introduced non-perturbative renormalization method to two\ntypes of lattice operators: the $\\Delta S=2$ four fermion operator and the\nheavy-light static axial current, which are relevant for the physics of $K$ and\n$B$ mesons respectively. The results of the non-perturbative calculations of\nthe renormalization constants are compared with the corresponding perturbative\nones."
    },
    {
        "anchor": "Perturbative and Nonperturbative Renormalization in Lattice QCD: We investigate the perturbative and nonperturbative renormalization of\ncomposite operators in lattice QCD restricting ourselves to operators that are\nbilinear in the quark fields (quark-antiquark operators). These include\noperators which are relevant to the calculation of moments of hadronic\nstructure functions. The nonperturbative computations are based on Monte Carlo\nsimulations with two flavors of clover fermions and utilize the\nRome-Southampton method also known as the RI-MOM scheme. We compare the results\nof this approach with various estimates from lattice perturbation theory, in\nparticular with recent two-loop calculations.",
        "positive": "Quenched Chiral Logarithms: I develop a diagrammatic method for calculating chiral logarithms in the\nquenched approximation. While not rigorous, the method is based on physically\nreasonable assumptions, which can be tested by numerical simulations. The main\nresults are that, at leading order in the chiral expansion, (a) there are no\nchiral logarithms in quenched $f_\\pi$, for $m_u=m_d$; (b) the chiral logarithms\nin $B_K$ and related kaon B-parameters are, for $m_d=m_s$, the same in the\nquenched approximation as in the full theory; (c) for $m_\\pi$ and the\ncondensate, there are extra chiral logarithms due to loops containing the\n$\\eta'$, which lead to a peculiar non-analytic dependence of these quantities\non the bare quark mass. Following the work of Gasser and Leutwyler, I discuss\nhow there is a predictable finite volume dependence associated with each chiral\nlogarithm. I compare the resulting predictions with numerical results: for most\nquantities the expected volume dependence is smaller than the errors, but for\n$B_V$ and $B_A$ there is an observed dependence which is consistent with the\npredictions."
    },
    {
        "anchor": "Comparing iterative methods to compute the overlap Dirac operator at\n  nonzero chemical potential: The overlap Dirac operator at nonzero quark chemical potential involves the\ncomputation of the sign function of a non-Hermitian matrix. In this talk we\npresent iterative Krylov subspace approximations, with deflation of critical\neigenvalues, which we developed to compute the operator on large lattices. We\ncompare the accuracy and efficiency of two alternative approximations based on\nthe Arnoldi and on the two-sided Lanczos method. The short recurrences used in\nthe latter method make it faster and more effective for realistic lattice\nsimulations.",
        "positive": "An Efficient Cluster Algorithm for CP(N-1) Models: We construct an efficient cluster algorithm for ferromagnetic SU(N)-symmetric\nquantum spin systems. Such systems provide a new regularization for CP(N-1)\nmodels in the framework of D-theory, which is an alternative non-perturbative\napproach to quantum field theory formulated in terms of discrete quantum\nvariables instead of classical fields. Despite several attempts, no efficient\ncluster algorithm has been constructed for CP(N-1) models in the standard\nformulation of lattice field theory. In fact, there is even a no-go theorem\nthat prevents the construction of an efficient Wolff-type embedding algorithm.\nWe present various simulations for different correlation lengths, couplings and\nlattice sizes. We have simulated correlation lengths up to 250 lattice spacings\non lattices as large as 640x640 and we detect no evidence for critical slowing\ndown."
    },
    {
        "anchor": "Perfect Scalars on the Lattice: We perform renormalization group transformations to construct optimally local\nperfect lattice actions for free scalar fields of any mass. Their couplings\ndecay exponentially. The spectrum is identical to the continuum spectrum, while\nthermodynamic quantities have tiny lattice artifacts. To make such actions\napplicable in simulations, we truncate the couplings to a unit hypercube and\nobserve that spectrum and thermodynamics are still drastically improved\ncompared to the standard lattice action. We show how preconditioning techniques\ncan be applied successfully to this type of action. We also consider a number\nof variants of the perfect lattice action, such as the use of an anisotropic or\ntriangular lattice, and modifications of the renormalization group\ntransformations motivated by wavelets. Along the way we illuminate the\nconsistent treatment of gauge fields, and we find a new fermionic fixed point\naction with attractive properties.",
        "positive": "Noncompact gauge fields on a lattice: SU(n) theories: Recently it has been found that in a noncompact lattice regularization of the\nSU(2) gauge theory the physical volume is larger than in the Wilson theory with\nthe same number of sites. In its original formulation the noncompact\nregularization is directly applicable to U(n) theories for any n and to SU(n)\ntheories for n=2. In this paper we extend it to SU(n) for any n and investigate\nsome of its properties."
    },
    {
        "anchor": "Stress distribution in quark--anti-quark and single quark systems at\n  nonzero temperature: We explore the distribution of the energy momentum tensor (EMT) around\nquark--anti-quark and single quark at nonzero temperature in SU(3) Yang-Mills\ngauge theory by extending our previous study on the EMT distribution in static\nquark--anti-quark systems in vacuum. We discuss the disappearance of the flux\ntube structure observed in the vacuum simulation. We investigate the total\nstress acting on the mid-plane between a quark and an anti-quark and show that\nit agrees with the force obtained from the derivative of the free energy. The\ncolor Debye screening effect in the deconfined phase is also discussed in terms\nof the EMT distribution.",
        "positive": "SU(3)-breaking ratios for $D_{(s)}$ and $B_{(s)}$ mesons: We present results for the $SU(3)$ breaking ratios of decay constants\n$f_{D_s}/f_D$ and $f_{B_s}/f_B$ and - for the first time with physical pion\nmasses - the ratio of bag parameters $B_{B_s}/B_{B_d}$, as well as the ratio\n$\\xi$, forming the ratio of the nonpeturbative contributions to neutral\n$B_{(s)}$ meson mixing. Our results are based on Lattice QCD simulations with\nchirally symmetric 2+1 dynamical flavors of domain wall fermions. Eight\nensembles at three different lattice spacing in the range $a = 0.11 -\n0.07\\,\\mathrm{fm}$ enter the analysis two of which feature physical light quark\nmasses. Multiple heavy quark masses are simulated ranging from below the charm\nquark mass to half the bottom quark mass. The $SU(3)$ breaking ratios display a\nvery benign heavy mass behaviour allowing for extrapolation to the physical\nbottom quark mass. The results in the continuum limit including all sources of\nsystematic errors are $f_{D_s}/f_D =\n1.1740(51)_\\mathrm{stat}(^{+68}_{-68})_\\mathrm{sys}$, $f_{B_s}/f_B =\n1.1949(60)_\\mathrm{stat}(^{+\\hphantom{0}95}_{-175})_\\mathrm{sys}$,\n$B_{B_s}/B_{B_d} = 0.9984(45)_\\mathrm{stat}(^{+80}_{-63})_\\mathrm{sys}$ and\n$\\xi = 1.1939(67)_\\mathrm{stat}(^{+\\hphantom{0}95}_{-177})_\\mathrm{sys}$.\nCombining these with experimentally measured values we extract the ratios of\nCKM matrix elements $|V_{cd}/V_{cs}| =\n0.2164(57)_\\mathrm{exp}(^{+12}_{-12})_\\mathrm{lat}$ and $|V_{td}/V_{ts}| =\n0.20329(41)_\\mathrm{exp}(^{+162}_{-301})_\\mathrm{lat}$."
    },
    {
        "anchor": "Radiative improvement of spin and Darwin terms in the NRQCD action: We present updated results for the radiative improvement of the \\sigma.B term\nand the spin-dependent four-fermion terms in the lattice NRQCD action, and\nfirst results for the radiative corrections to the NRQCD Darwin term and\nspin-independent four-fermion terms. The spin-dependent terms have significant\nimpact on getting the correct hyperfine splitting for both bottomonium and\nheavy-light mesons, while the spin-independent terms suffer from a conspiracy\nbetween lattice artifacts and severe IR divergences that complicates their\nevaluation.",
        "positive": "Numerical Simulations of PT-Symmetric Quantum Field Theories: Many non-Hermitian but PT-symmetric theories are known to have a real\npositive spectrum. Since the action is complex for there theories, Monte Carlo\nmethods do not apply. In this paper the first field-theoretic method for\nnumerical simulations of PT-symmetric Hamiltonians is presented. The method is\nthe complex Langevin equation, which has been used previously to study complex\nHamiltonians in statistical physics and in Minkowski space. We compute the\nequal-time one-point and two-point Green's functions in zero and one dimension,\nwhere comparisons to known results can be made. The method should also be\napplicable in four-dimensional space-time. Our approach may also give insight\ninto how to formulate a probabilistic interpretation of PT-symmetric theories."
    },
    {
        "anchor": "Electroweak three-body decays in the presence of two- and three-body\n  bound states: Recently, formalism has been derived for studying electroweak transition\namplitudes for three-body systems both in infinite and finite volumes. The\nformalism provides exact relations that the infinite-volume amplitudes must\nsatisfy, as well as a relationship between physical amplitudes and\nfinite-volume matrix elements, which can be constrained from lattice QCD\ncalculations. This formalism poses additional challenges when compared with the\nanalogous well-studied two-body equivalent one, including the necessary step of\nsolving integral equations of singular functions. In this work, we provide some\nnon-trivial analytical and numerical tests on the aforementioned formalism. In\nparticular, we consider a case where the three-particle system can have\nthree-body bound states as well as bound states in the two-body subsystem. For\nkinematics below the three-body threshold, we demonstrate that the scattering\namplitudes satisfy unitarity. We also check that for these kinematics the\nfinite-volume matrix elements are accurately described by the formalism for\ntwo-body systems up to exponentially suppressed corrections. Finally, we verify\nthat in the case of the three-body bound state, the finite-volume matrix\nelement is equal to the infinite-volume coupling of the bound state, up to\nexponentially suppressed errors.",
        "positive": "Alpha_s from the Lattice Potential: We present an extensive study on the direct determination of the running\ncoupling alpha_s from the static quark antiquark force at short distances, in\nquenched QCD. We find from our high statistics potential analysis that alpha_qq\nexhibits two-loop asymptotic behaviour for momenta as low as .5 GeV. As a\nresult, we determine the zero flavour Lambda-parameter to be Lambda^0_MSBAR =\n0.630(38)\\sqrt{\\sigma} = 293(18)^{+25}_{-63} MeV. A rough estimate of full QCD\neffects leads to the five flavour value alpha_MSBAR(m_Z) = .102^{+6}_{-11}. A\ncomparison with other lattice results is made."
    },
    {
        "anchor": "The Standard Model from a New Phase Transition on the Lattice: Several years ago it was conjectured in the so-called Roma Approach, that\ngauge fixing is an essential ingredient in the lattice formulation of chiral\ngauge theories. In this paper we discuss in detail how the gauge-fixing\napproach may be realized. As in the usual (gauge invariant) lattice\nformulation, the continuum limit corresponds to a gaussian fixed point, that\nnow controls both the transversal and the longitudinal modes of the gauge\nfield. A key role is played by a new phase transition separating a conventional\nHiggs or Higgs-confinement phase, from a phase with broken rotational\ninvariance. In the continuum limit we expect to find a scaling region, where\nthe lattice correlators reproduce the euclidean correlation functions of the\ntarget (chiral) gauge theory, in the corresponding continuum gauge.",
        "positive": "Electric and Magnetic Fluxes in SU(2) Yang-Mills Theory: We measure the free energies in SU(2) of static fundamental charges and\ncenter monopoles. Dual to temporal center fluxes, the former provide a\nwell-defined (dis)order parameter for deconfinement. In contrast, the monopole\nfree energies vanish in the thermodynamic limit at all temperatures and are\nthus irrelevant for the transition."
    },
    {
        "anchor": "Dirac operator and Ising model on a compact 2D random lattice: Lattice formulation of a fermionic field theory defined on a randomly\ntriangulated compact manifold is discussed, with emphasis on the topological\nproblem of defining spin structures on the manifold. An explicit construction\nis presented for the two-dimensional case and its relation with the Ising model\nis discussed. Furthermore, an exact realization of the Kramers-Wannier duality\nfor the two-dimensional Ising model on the manifold is considered. The global\nproperties of the field are discussed. The importance of the GSO projection is\nstressed. This projection has to be performed for the duality to hold.",
        "positive": "Nucleon matrix elements with domain wall fermions: We present the status of our calculation of the first few moments of the\nnucleon structure functions. Our calculations are done using domain wall\nfermions in the quenched approximation with the DBW2 gauge action at 1.3GeV\ninverse lattice spacing."
    },
    {
        "anchor": "O(a) improved QCD: The 3-loop beta-function, and the critical hopping\n  parameter: We calculate the 3-loop bare $\\beta$-function of QCD, formulated on the\nlattice with the clover fermionic action. The dependence of our result on the\nnumber of colors $N$, the number of fermionic flavors $N_f$, and the clover\nparameter $c_{SW}$, is shown explicitly. A direct outcome of our calculation is\nthe two-loop relation between the bare coupling constant $g_0$ and the one\nrenormalized in the MS-bar scheme. Further, we can immediately derive the\nthree-loop correction to the relation between the lattice $\\Lambda$-parameter\nand $g_0$, which turns out to be very pronounced.\n  We also calculate the critical value of the hopping parameter, $\\kappa_c$, in\nthe clover action, to two loops in perturbation theory. This quantity is an\nadditive renormalization; as such, it exhibits a linear divergence in the\nlattice spacing. We compare our results to non perturbative evaluations of\n$\\kappa_c$ coming from MC simulations.",
        "positive": "$K \\to \u03c0$ matrix elements of the chromomagnetic operator on the\n  lattice: We present the results of the first lattice QCD calculation of the $K \\to\n\\pi$ matrix elements of the chromomagnetic operator $O_{CM} = g\\, \\bar s\\,\n\\sigma_{\\mu\\nu} G_{\\mu\\nu} d$, which appears in the effective Hamiltonian\ndescribing $\\Delta S = 1$ transitions in and beyond the Standard Model. Having\ndimension 5, the chromomagnetic operator is characterized by a rich pattern of\nmixing with operators of equal and lower dimensionality. The multiplicative\nrenormalization factor as well as the mixing coefficients with the operators of\nequal dimension have been computed at one loop in perturbation theory. The\npower divergent coefficients controlling the mixing with operators of lower\ndimension have been determined non-perturbatively, by imposing suitable\nsubtraction conditions. The numerical simulations have been carried out using\nthe gauge field configurations produced by the European Twisted Mass\nCollaboration with $N_f = 2+1+1$ dynamical quarks at three values of the\nlattice spacing. Our result for the B-parameter of the chromomagnetic operator\nat the physical pion and kaon point is $B_{CMO}^{K \\pi} = 0.273 ~ (70)$, while\nin the SU(3) chiral limit we obtain $B_{CMO} = 0.072 ~ (22)$. Our findings are\nsignificantly smaller than the model-dependent estimate $B_{CMO} \\sim 1 - 4$,\ncurrently used in phenomenological analyses, and improve the uncertainty on\nthis important phenomenological quantity."
    },
    {
        "anchor": "Strong Coupling Lattice QCD in the Continuous Time Limit: We present results for lattice QCD with staggered fermions in the limit of\ninfinite gauge coupling, obtained from a worm-type Monte Carlo algorithm on a\ndiscrete spatial lattice but with continuous Euclidean time. This is obtained\nby sending both the anisotropy parameter $\\xi=a_\\sigma/a_\\tau$ and the number\nof time-slices $N_\\tau$ to infinity, keeping the ratio $aT=\\xi/N\\tau$ fixed.\nThe obvious gain is that no continuum extrapolation $N_\\tau \\rightarrow \\infty$\nhas to be carried out. Moreover, the algorithm is faster and the sign problem\ndisappears. We derive the continuous time partition function and the\ncorresponding Hamiltonian formulation. We compare our computations with those\non discrete lattices and study both zero and finite temperature properties of\nlattice QCD in this regime.",
        "positive": "Results from 3D Electroweak Phase Transition Simulations: We study the phase transition in SU(2)-Higgs model on the lattice using the\n3D dimensionally reduced formalism. The 3D formalism enables us to obtain\nhighly accurate Monte Carlo results, which we extrapolate both to the infinite\nvolume and to the continuum limit. Our formalism also provides for a\nwell-determined and unique way to relate the results to the perturbation\ntheory. We measure the critical temperature, latent heat and interface tension\nfor Higgs masses up to 70 GeV."
    },
    {
        "anchor": "Monopole and instanton effects in QCD: We aim to show the effects of the magnetic monopoles and instantons in\nquantum chromodynamics (QCD) on observables; therefore, we introduce a monopole\nand anti-monopole pair in the QCD vacuum of a quenched SU(3) by applying the\nmonopole creation operator to the vacuum. We calculate the eigenvalues and\neigenvectors of the overlap Dirac operator that preserves the exact chiral\nsymmetry in lattice gauge theory using these QCD vacua. We then investigate the\neffects of magnetic monopoles and instantons. First, we confirm the monopole\neffects as follows: (i) The monopole creation operator makes the monopoles and\nanti-monopoles in the QCD vacuum. (ii) A monopole and anti-monopole pair\ncreates an instanton or anti-instanton without changing the structure of the\nQCD vacuum. (iii) The monopole and anti-monopole pairs change only the scale of\nthe spectrum distribution without affecting the spectra of the Dirac operator\nby comparing the spectra with random matrix theory. Next, we find the instanton\neffects by increasing the number density of the instantons and anti-instantons\nas follows: (iv) The decay constants of the pseudoscalar increase. (v) The\nvalues of the chiral condensate, which are defined as negative numbers,\ndecrease. (vi) The light quarks and the pseudoscalar mesons become heavy. The\ncatalytic effect on the charged pion is estimated using the numerical results\nof the pion decay constant and the pion mass. (vii) The decay width of the\ncharged pion becomes wider than the experimental result, and the lifetime of\nthe charged pion becomes shorter than the experimental result. These are the\neffects of the monopoles and instantons in QCD.",
        "positive": "Phase quenching in finite-density QCD: models, holography, and lattice: Finite-density QCD is difficult to study numerically because of the sign\nproblem. We prove that, in a certain region of the phase diagram, the phase\nquenched approximation is exact to O(Nf/Nc). It is true for any physical\nobservables. We also consider the implications for the lattice simulations and\nfind a quantitative evidence for the validity of the phase quenching from\nexisting lattice QCD results at Nc=3. Our results show that the phase-quench\napproximation is rather good already at Nc=3, and the 1/Nc correction can be\nincorporated by the phase reweighting method without suffering from the overlap\nproblem. We also show the same equivalence in effective models and holographic\nmodels."
    },
    {
        "anchor": "Three topics of monopole dynamics in abelian projected QCD: Three topics about monopole dynamics after abelian projection are reported.\nThe first is the new and detailed analyses of $SU(2)$ monopole action obtained\nafter the block-spin transformation on the dual lattice. The $b=na(\\beta)$\ndependence for all couplings are well fitted with a universal curve. The\ndistance dependence of the couplings is well reproduced by a massive propagator\nwith the mass $m=0.8$ in unit of $b$. The second is the $SU(3)$ monopole action\nrecently obtained. The third is new interesting gauges showing abelian and\nmonopole dominances as in the maximally abelian gauge.",
        "positive": "Masses and Decay Constants of Heavy-Light Mesons Using the Multistate\n  Smearing Technique: We present results for f_B and masses of low-lying heavy-light mesons.\nCalculations were performed in the quenched approximation using multistate\nsmearing functions generated from a spinless relativistic quark model\nHamiltonian. Beta values range from 5.7 to 6.3, and light quark masses\ncorresponding to pion masses as low as 300 MeV are computed at each value. We\nuse the 1P--1S charmonium splitting to set the overall scale."
    },
    {
        "anchor": "Continuum Thermodynamics of the SU(N) Gauge Theory: The thermodynamics of the deconfined phase of the SU(N) gauge theory is\nstudied. Careful study is made of the approach to the continuum limit. The\nlatent heat of the deconfinement transition is studied, for the theories with\n3, 4 and 6 colors. Continuum estimates of various thermodynamic quantities are\nstudied, and the approach to conformality investigated. The bulk thermodynamic\nquantities at different N are compared, to investigate the validity of 't Hooft\nscaling at these values of N.",
        "positive": "Conformality in many-flavour lattice QCD at strong coupling: It is widely believed that chiral symmetry is spontaneously broken at zero\ntemperature in the strong coupling limit of staggered fermions, for any number\nof colors and flavors. Using Monte Carlo simulations, we show that this\nconventional wisdom, based on a mean-field analysis, is wrong. For sufficiently\nmany fundamental flavors, chiral symmetry is restored via a bulk, first-order\ntransition. This chirally symmetric phase appears to be analytically connected\nwith the expected conformal window of many-flavor continuum QCD. We perform\nsimulations in the chirally symmetric phase at zero quark mass for various\nsystem sizes L, and measure the torelon mass, the Dirac spectrum and the hadron\nspectrum. All masses go to zero with 1/L. L is hence the only infrared length\nscale. Thus, the strong-coupling chirally restored phase appears as a\nconvenient laboratory to study IR-conformality. Finally, we present a\nconjecture for the phase diagram of lattice QCD as a function of the bare\ncoupling and the number of quark flavors."
    },
    {
        "anchor": "Cluster Percolation and Thermal Critical Behaviour: Continuous phase transitions in spin systems can be formulated as percolation\nof suitably defined clusters. We review this equivalence and then discuss how\nin a similar way, the color deconfinement transition in SU(2) gauge theory can\nbe treated as a percolation phenomenon. In the presence of an external field,\nspin systems cease to show thermal critical behavior, but the geometric\npercolation transition persists (Kert\\'esz line). For $H\\not=0$, we study the\nrelation between percolation and pseudocritical behavior, both for continuous\nand first order transitions, and show that it leads to the necessity of an\n$H$-dependent cluster definition. A viable formulation of this kind could serve\nas definition of deconfinement in QCD with dynamical quarks.",
        "positive": "Confinement and Topological Charge in the Abelian Gauge of QCD: We study the relation between instantons and monopoles in the abelian gauge.\nFirst, we investigate the monopole in the multi-instanton solution in the\ncontinuum Yang-Mills theory using the Polyakov gauge. At a large instanton\ndensity, the monopole trajectory becomes highly complicated, which can be\nregarded as a signal of monopole condensation. Second, we study instantons and\nmonopoles in the SU(2) lattice gauge theory both in the maximally abelian (MA)\ngauge and in the Polyakov gauge. Using the $16^3 \\times 4$ lattice, we find\nmonopole dominance for instantons in the confinement phase even at finite\ntemperatures. A linear-type correlation is found between the total\nmonopole-loop length and the integral of the absolute value of the topological\ndensity (the total number of instantons and anti-instantons) in the MA gauge.\nWe conjecture that instantons enhance the monopole-loop length and promote\nmonopole condensation."
    },
    {
        "anchor": "Restoration of Rotational Symmetry in the Continuum Limit of Lattice\n  Field Theories: We explore how rotational invariance is systematically recovered from\ncalculations on hyper-cubic lattices through the use of smeared lattice\noperators that smoothly evolve into continuum operators with definite angular\nmomentum as the lattice-spacing is reduced. Perturbative calculations of the\nangular momentum violation associated with such operators at tree-level and at\none-loop are presented in phi^4 theory and QCD. Contributions from these\noperators that violate rotational invariance occur at tree-level, with\ncoefficients that are suppressed by O(a^2) in the continuum limit. Quantum\nloops do not modify this behavior in phi^4, nor in QCD if the gauge-fields are\nsmeared over a comparable spatial region. Consequently, the use of this type of\noperator should, in principle, allow for Lattice QCD calculations of the higher\nmoments of the hadron structure functions.",
        "positive": "Two- and three-body interactions in $\\varphi^4$ theory from lattice\n  simulations: We calculate the one-, two- and three-particle energy levels for different\nlattice volumes in the complex $\\varphi^4$ theory on the lattice. We argue that\nthe exponentially suppressed finite-volume corrections for the two- and\nthree-particle energy shifts can be reduced significantly by using the single\nparticle mass, which includes the finite-size effects. We show numerically\nthat, for a set of bare parameters, corresponding to the weak repulsive\ninteraction, one can reliably extract the two- and three-particle energy\nshifts. From those, we extract the scattering length, the effective range and\nthe effective three-body coupling. We show that the parameters, extracted from\nthe two- and three-particle energy shifts, are consistent. Moreover, the\neffective three-body coupling is significantly different from zero."
    },
    {
        "anchor": "HMC algorithm with multiple time scale integration and mass\n  preconditioning: We present a variant of the HMC algorithm with mass preconditioning\n(Hasenbusch acceleration) and multiple time scale integration. We have tested\nthis variant for standard Wilson fermions at beta=5.6 and at pion masses\nranging from 380 MeV to 680 MeV. We show that in this situation its performance\nis comparable to the recently proposed HMC variant with domain decomposition as\npreconditioner. We give an update of the ``Berlin Wall'' figure, comparing the\nperformance of our variant of the HMC algorithm to other published performance\ndata. Advantages of the HMC algorithm with mass preconditioning and multiple\ntime scale integration are that it is straightforward to implement and can be\nused in combination with a wide variety of lattice Dirac operators.",
        "positive": "A computational system for lattice QCD with overlap Dirac quarks: We outline the essential features of a Linux PC cluster which is now being\ndeveloped at National Taiwan University, and discuss how to optimize its\nhardware and software for lattice QCD with overlap Dirac quarks. At present,\nthe cluster constitutes of 30 nodes, with each node consisting of one Pentium 4\nprocessor (1.6/2.0 GHz), one Gbyte of PC800 RDRAM, one 40/80 Gbyte hard disk,\nand a network card. The speed of this system is estimated to be 30 Gflops, and\nits price/performance ratio is better than $1.0/Mflops for 64-bit (double\nprecision) computations in quenched lattice QCD with overlap Dirac quarks."
    },
    {
        "anchor": "Simulating the All-Order Hopping Expansion II: Wilson Fermions: We investigate the extension of the Prokof'ev-Svistunov worm algorithm to\nWilson lattice fermions in an external scalar field. We effectively simulate by\nMonte Carlo the graphs contributing to the hopping expansion of the two-point\nfunction on a finite lattice to arbitrary order. Tests are conducted for a\nconstant background field i. e. free fermions at some mass. For the method\nintroduced here this is expected to be a representative case. Its advantage is\nthat we know the exact answers and can thus make stringent tests on the\nnumerics. The approach is formulated in both two and three space-time\ndimensions. In D=2 Wilson fermions enjoy special positivity properties and the\nsimulation is similarly efficient as in the Ising model. In D=3 the method also\nworks at sufficiently large mass, but there is a hard sign problem in the\npresent formulation hindering us to take the continuum limit.",
        "positive": "$B\\!\\to\\!D^{(*)}\\ell\u03bd$ form factors from lattice QCD with relativistic\n  heavy quarks: We report on our calculation of the B \\to D^(*) \\ell \\nu form factors in 2+1\nflavor lattice QCD. The M\\\"obius domain-wall action is employed for light,\nstrange, charm and bottom quarks. At lattice cutoffs 1/a \\sim 2.4, 3.6 and 4.5\nGeV, we simulate bottom quark masses up to 0.7/a to control discretization\nerrors. The pion mass is as low as 230 MeV. We extrapolate the form factors to\nthe continuum limit and physical quark masses, and make a comparison with\nrecent phenomenological analyses."
    },
    {
        "anchor": "Charged Hadron Properties in Background Electric Fields: We report on a lattice calculation demonstrating a novel new method to\nextract the electric polarizability of charged pseudo-scalar mesons by\nanalyzing two point correlation functions computed in classical background\nelectric fields.",
        "positive": "Comment on \"Chiral anomalies and rooted staggered fermions\": In hep-lat/0701018, Creutz claims that the rooting trick used in simulations\nof staggered fermions to reduce the number of tastes misses key physics\nwhenever the desired theory has an odd number of continuum flavors, and uses\nthis argument to call into question the rooting trick in general. Here we show\nthat his argument fails as the continuum limit is approached, and therefore\ndoes not imply any problem for staggered simulations. We also show that the\ncancellations necessary to restore unitarity in physical correlators in the\ncontinuum limit are a straightforward consequence of the restoration of taste\nsymmetry."
    },
    {
        "anchor": "Spectrum of very excited $\u03a3_g^+$ flux tubes in SU(3) gauge theory: Spectra with full towers of levels are expected due to the quantization of\nthe string vibrations, however different theoretical models exist for the\nexcitation spectra. First principle computations are important to test the\ndifferent models and to search for novel phenomena, but so far only a few\nexcited states of QCD flux tubes have been studied with pure gauge SU(3)\nlattice QCD in 3+1 dimensions. We thus aim to study a spectrum of flux tubes\nwith static quark and antiquark sources up to a significant number of\nexcitations. We specialize on the spectrum of the most symmetric case, namely\n$\\Sigma_g^+$, where up to two levels are already published in the literature.\nTo achieve the highest possible excitation level, we construct a large set of\noperators with the correct symmetry, solve the generalized eigenvalue problem\nand compare the results of different lattice QCD gauge actions with different\nlattice spacings and anisotropies.",
        "positive": "Chiral violations from one-loop domain wall fermions: We present results from lattice perturbation theory for the residual mass and\nother matrix elements measuring the breaking of chiral symmetry in domain-wall\nfermions. We have used the exact propagators corresponding to a finite number\nof points in the fifth dimensions, and results were obtained for several\nchoices of the domain-wall parameters."
    },
    {
        "anchor": "Lattice QCD with an inhomogeneous magnetic field background: The magnetic fields generated in non-central heavy-ion collisions are among\nthe strongest fields produced in the Universe, reaching magnitudes comparable\nto the scale of the strong interactions. Backed by model simulations, the\nresulting field is expected to be spatially modulated, deviating significantly\nfrom the commonly considered uniform profile. To improve our understanding of\nthe physics of quarks and gluons under such extreme conditions, we use lattice\nQCD simulations with $2+1$ staggered fermion flavors with physical quark masses\nand an inhomogeneous magnetic background for a range of temperatures covering\nthe QCD phase transition. We assume a $1/\\cosh^2$ function to model the field\nprofile and vary its strength to analyze the impact on the computed observables\nand on the transition. We calculate local chiral condensates, local Polyakov\nloops and estimate the size of lattice artifacts. We find that both observables\nshow non-trivial spatial features due to the interplay between the sea and the\nvalence effects.",
        "positive": "Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass: We report the first Lattice QCD calculation using the almost physical pion\nmass mpi=149 MeV that agrees with experiment for four fundamental isovector\nobservables characterizing the gross structure of the nucleon: the Dirac and\nPauli radii, the magnetic moment, and the quark momentum fraction. The key to\nthis success is the combination of using a nearly physical pion mass and\nexcluding the contributions of excited states. An analogous calculation of the\nnucleon axial charge governing beta decay has inconsistencies indicating a\nsource of bias at low pion masses not present for the other observables and\nyields a result that disagrees with experiment."
    },
    {
        "anchor": "Critical slowing down of topological modes: We investigate the critical slowing down of the topological modes using local\nupdating algorithms in lattice 2-d CP^(N-1) models. We show that the\ntopological modes experience a critical slowing down that is much more severe\nthan the one of the quasi-Gaussian modes relevant to the magnetic\nsusceptibility, which is characterized by $\\tau_{\\rm mag} \\sim \\xi^z$ with\n$z\\approx 2$. We argue that this may be a general feature of Monte Carlo\nsimulations of lattice theories with non-trivial topological properties, such\nas QCD, as also suggested by recent Monte Carlo simulations of 4-d SU(N)\nlattice gauge theories.",
        "positive": "Reliable estimation of the radius of convergence in finite density QCD: We study different estimators of the radius of convergence of the Taylor\nseries of the pressure in finite density QCD. We adopt the approach in which\nthe radius of convergence is estimated first in a finite volume, and the\ninfinite-volume limit is taken later. This requires an estimator for the radius\nof convergence that is reliable in a finite volume. Based on general arguments\nabout the analytic structure of the partition function in a finite volume, we\ndemonstrate that the ratio estimator cannot work in this approach, and propose\nthree new estimators, capable of extracting reliably the radius of convergence,\nwhich coincides with the distance from the origin of the closest Lee-Yang zero.\nWe also provide an estimator for the phase of the closest Lee-Yang zero,\nnecessary to assess whether the leading singularity is a true critical point.\nWe demonstrate the usage of these estimators on a toy model, namely 4 flavors\nof unimproved staggered fermions on a small $6^3 \\times 4$ lattice, where both\nthe radius of convergence and the Taylor coefficients to any order can be\nobtained by a direct determination of the Lee-Yang zeros. Interestingly, while\nthe relative statistical error of the Taylor expansion coefficients steadily\ngrows with order, that of our estimators stabilizes, allowing for an accurate\nestimate of the radius of convergence. In particular, we show that despite the\nmore than 100\\% error bars on high-order Taylor coefficients, the given\nensemble contains enough information about the radius of convergence."
    },
    {
        "anchor": "The muon $g-2$ with four flavors of staggered quarks: We present updated results for the light-quark connected part of the leading\nhadronic contribution to the muon $g-2$ from configurations with 2+1+1 flavors\nof HISQ quarks using the time-momentum representation of the electromagnetic\ncurrent correlator. We have added statistics on two ensembles as well as a\nfourth lattice spacing using configurations that have been generated by the\nMILC collaboration at the physical pion mass. Additionally we account for the\nleading finite-volume and taste-breaking effects using Staggered Chiral\nPerturbation Theory at NNLO.",
        "positive": "The Fluctuations of the Quark Number and of the Chiral Condensate: The distributions of the quark number and chiral condensate over the gauge\nfields are computed for QCD in Euclidean space at nonzero quark chemical\npotential. As both operators are non-hermitian the distributions are in the\ncomplex plane. Moreover, because of the sign problem, the distributions are not\nreal and positive. The computations are carried out within leading order chiral\nperturbation theory and give a direct insight into the delicate cancellations\nthat take place in contributions to the total baryon number and the chiral\ncondensate."
    },
    {
        "anchor": "Topology and glueballs in SU(7) Yang-Mills with open boundary conditions: It is well known that the topology of gauge configurations generated in a\nMarkov Monte-Carlo chain freezes as the continuum limit is approached. The\ncorresponding autocorrelation time increases exponentially with the inverse\nlattice spacing, affecting the ergodicity of the simulation. In SU(N) gauge\ntheories for large N this problem sets in at much coarser lattice spacings than\nfor N=3. This means that its systematics can be studied on lattices that are\nsmaller in terms of the number of lattice sites. It has been shown that using\nopen boundary conditions in time allows instantons to be created and destroyed,\nrestoring topological mobility and ergodicity. However, with open boundary\nconditions translational invariance is lost and the influence of spurious\nstates propagating from the boundary into the bulk on physical correlators\nneeds to be carefully evaluated. Moreover, while the total topological charge\ncan be changed, the mobility of instantons across the lattice is still reduced.\nWe consider SU(7) Yang-Mills theory and analyse its topological content in the\nperiodic and open boundary condition cases. We also investigate scalar and\npseudo-scalar glueball correlation functions.",
        "positive": "Numerical study of the $\\mathcal{N}=2$ Landau--Ginzburg model with two\n  superfields: In the low energy limit, the two-dimensional massless $\\mathcal{N}=2$\nWess--Zumino (WZ) model with a quasi-homogeneous superpotential is believed to\nbecome a superconformal field theory. This conjecture of the Landau--Ginzburg\n(LG) description has been studied numerically in the case of the $A_2$, $A_3$,\nand $E_6$ minimal models. In this paper, by using a supersymmetric-invariant\nnon-perturbative formulation, we simulate the WZ model with two superfields\ncorresponding to the $D_3$, $D_4$, and $E_7$ models. Then, we numerically\ndetermine the central charge, and obtain the results that are consistent with\nthe conjectured correspondence. We hope that this numerical approach, when\nfurther developed, will be useful to investigate superstring theory via the\nLG/Calabi--Yau correspondence."
    },
    {
        "anchor": "$I = 3$ three-pion scattering amplitude from lattice QCD: We analyze the spectrum of two- and three-pion states of maximal isospin\nobtained recently for isosymmetric QCD with pion mass $M\\approx 200\\;$MeV in\nRef. [1]. Using the relativistic three-particle quantization condition, we find\n$\\sim 2 \\sigma$ evidence for a nonzero value for the contact part of the\nthree-$\\pi^+$ ($I=3$) scattering amplitude. We also compare our results to\nleading-order chiral perturbation theory. We find good agreement at threshold,\nand some tension in the energy dependent part of the three-$\\pi^+$scattering\namplitude. We also find that the two-$\\pi^+$ ($I=2$) spectrum is fit well by an\n$s$-wave phase shift that incorporates the expected Adler zero.",
        "positive": "Lattice Chirality: The external fermion propagator and the internal fermion propagator in the\noverlap are given by different matrices. A generic problem (formulated by\nPelissetto) faced by all chiral, non-local, propagators of Rebbi type is\navoided in this manner. Nussinov-Weingarten-Witten mass inequalities are\nexactly preserved. It is sketched how to obtain simple lattice chiral Yukawa\nmodels and simple expressions for covariant currents. Going beyond my oral\npresentation, I have added to the write-up several comments on Niedermayer's\ntalk. His transparencies are available on the internet."
    },
    {
        "anchor": "Excitations of Ising Strings on a Lattice: The 3d Ising model in the low temperature (ferromagnetic) phase describes\ndynamics of two-dimensional surfaces -- domain walls between clusters of\nparallel spins. The Kramers--Wannier duality maps these surfaces into\nworldsheets of confining strings in the Wegner's ${\\mathbb Z}_2$ gauge theory.\nWe study the excitation spectrum of long Ising strings by simulating the\n${\\mathbb Z}_2$ gauge theory on a lattice. We observe a strong mixing between\nstring excitations and the lightest glueball state and do not find indications\nfor light massive resonances on the string worldsheet.",
        "positive": "Optimizing Distillation for charmonium and glueballs: We study the charmonium spectrum on an ensemble with two heavy dynamical\nquarks with a mass at half the physical charm quark mass. Operators for\ndifferent quantum numbers are used in the framework of distillation with\ndifferent smearing profiles to increase the overlap with ground and excited\nstates. The use of exact distillation, large statistics and the absence of\nlight quarks gives robust results for the charmonium spectrum. We also present\npreliminary results for the glueball spectrum in this theory."
    },
    {
        "anchor": "Domain-wall fermions and chiral symmetries: We investigate chiral properties of the domain-wall fermion (DWF) system.\nAfter a brief introduction for the DWF, we summarize the recent numerical\nresults on the chiral properties of the domain-wall QCD (DWQCD), which seem\nmutually inconsistent. We next derive a formula which connects a chiral\nsymmetry breaking term in the five dimensional DWF Ward-Takahashi identity with\nthe four-dimensional hermitian Wilson-Dirac operator. Based on this formula, we\npropose a solution, which resolves the inconsistency among recent numerical\ndata, and give a consistent picture of the chiral properties of the DWQCD.",
        "positive": "Monopole condensation in two-flavour Adjoint QCD: In QCD with adjoint fermions (aQCD) the deconfining transition takes place at\na lower temperature than the chiral transition. We study the two transitions by\nuse of the Polyakov Loop, the monopole order parameter and the chiral\ncondensate. The deconfining transition is first order, the chiral is a\ncrossover. The order parameters for confinement are not affected by the chiral\ntransition. We conclude that the degrees of freedom relevant to confinement are\ndifferent from those describing chiral symmetry."
    },
    {
        "anchor": "S-wave pi-K scattering length from lattice QCD: The $S$-wave $\\pi K$ scattering lengths are calculated for both the isospin\n1/2 and 3/2 channels in the lattice QCD by using the finite size formula. We\nperform the calculation with $N_f=2+1$ gauge configurations generated on $32^3\n\\times 64$ lattice using the Iwasaki gauge action and nonperturbatively\n$O(a)$-improved Wilson action at $1/a = 2.17$ GeV. The quark masses correspond\nto $m_\\pi = 0.30 - 0.70$ GeV. For $I=1/2$, to separate the contamination from\nexcited states, we construct a $2 \\times 2$ matrix of the time correlation\nfunction and diagonalize it. Here, we adopt the two kinds of operators,\n$\\bar{s}u$ and $\\pi K$. It is found that the signs of the scattering lengths\nare in agreement with experiment, namely attraction in $I=1/2$ and repulsion in\n$I=3/2$. We investigate the quark-mass dependence of the scattering lengths and\nalso discuss the limitation of chiral perturbation theory.",
        "positive": "Accurate Scale Determinations for the Wilson Gauge Action: Accurate determinations of the physical scale of a lattice action are\nrequired to check scaling and take the continuum limit. We present a high\nstatistics study of the static potential for the SU(3) Wilson gauge action on\ncoarse lattices ($5.54 \\leq \\beta \\leq 6.0$). Using an improved analysis\nprocedure we determine the string tension and the Sommer scale $r_0$ (and\nrelated quantities) to 1% accuracy, including all systematic errors. Combining\nour results with earlier ones on finer lattices, we present parameterizations\nof these quantities that should be accurate to about 1% for $5.6 \\leq \\beta\n\\leq 6.5$. We estimate the $\\La$-parameter of quenched QCD to be $\\La_\\MSb =\n247(16)$ MeV."
    },
    {
        "anchor": "Asymptotic series for distributions: Asymptotic expansions for a wide class of distribution are studied. A simple\nmethod for computation of the series coefficients is suggested. The case when\nregularization parameter of the distribution depends on the asymptotic\nparameter is considered.",
        "positive": "Phase diagram of QCD with two degenerate staggered quarks: We present preliminary results about the critical line of QCD with two\ndegenerate staggered quarks at nonzero temperature and chemical potential,\nobtained by the method of analytic continuation. As in our previous studies\nwith different numbers of colors and flavors, we find deviations from a simple\nquadratic dependence on the chemical potential. We comment on the shape of the\ncritical line at real chemical potential and give an estimate of the curvature\nof the critical line, both for quark chemical potential and isospin chemical\npotential."
    },
    {
        "anchor": "1/N Expansion and Particle Spectrum in Induced QCD: We study the 1/N expansion in the recently proposed model of the lattice\ngauge theory induced by heavy scalar field in adjoint representation. In the\nfirst approximation the fluctuations of the density of eigenvalues of the\nscalar field are Gaussian, so that the scalar glueball spectrum is defined from\nthe corresponding linear wave equation.",
        "positive": "SUSY Ward identities in 1-loop perturbation theory: We present preliminary results of a study of the supersymmetric (SUSY) Ward\nidentities (WIs) for the N=1 SU(2) SUSY Yang-Mills theory in the context of\none-loop lattice perturbation theory. The supersymmetry on the lattice is\nexplicitly broken by the gluino mass and the lattice artifacts. However, the\nrenormalization of the supercurrent can be carried out in a scheme that\nrestores the nominal continuum WIs. The perturbative calculation of the\nrenormalization constants and mixing coefficients for the local supercurrent is\npresented."
    },
    {
        "anchor": "Precision computation of the strange quark's mass in quenched QCD: We determine the renormalization group invariant quark mass corresponding to\nthe sum of the strange and the average light quark mass in the quenched\napproximation of QCD, using as essential input the mass of the K-mesons. In the\ncontinuum limit we find $(M_s + M_{light})/F_K=0.874(29)$, which includes\nsystematic errors. Translating this non-perturbative result into the running\nquark masses in the $\\msbar$-scheme at $\\mu=2 GeV$ and using the quark mass\nratios from chiral perturbation theory, we obtain $\\mbar_s(2 GeV)=97(4) MeV$.\nWith the help of recent results by the CP-PACS Collaboration, we estimate that\na 10% higher value would be obtained if one replaced $F_K$ by the nucleon mass\nto set the scale. This is a typical ambiguity in the quenched approximation.",
        "positive": "Low-lying Odd-parity States of the Nucleon in Lattice QCD: The world's first examination of the odd-parity nucleon spectrum at light\nquark masses in 2+1 flavor lattice QCD is presented. Configurations generated\nby the PACS-CS collaboration and made available through the ILDG are used, with\nthe lightest pion mass at 156 MeV. A novel method for tracking the individual\nenergy eigenstates as the quark mass changes is introduced. The success of this\napproach reveals the flow of the states towards the physical masses. Using the\ncorrelation matrix method, the two lowest-energy states revealed are found to\nbe in accord with the physical spectrum of Nature."
    },
    {
        "anchor": "The static tetraquark and pentaquark potentials: We evaluate the static $qq\\bar{q}\\bar{q}$ and $qqqq\\bar{q}$ potentials in the\nquenched theory at $\\beta=5.8$ and $\\beta=6.0$ on a lattice of size $16^3\\times\n32$. We compare the static potentials to the sum of two meson potentials for\nthe tetraquark system and to the sum of the baryonic and mesonic potentials for\nthe pentaquark state, as well as, with the confining potential obtained in the\nstrong coupling expansion.",
        "positive": "Simulated random surfaces and effective string models in 3D Z(2) gauge\n  theory: All-order strong coupling simulations have been used to derive precise\nenergies of string states in the confined phase of three dimensional Z(2)\nlattice gauge theory. The behavior of the ground state energy is here compared\nwith predictions of effective string theory. Our new data reported here are\nconsistent with known universal terms of the long string length ($L_0$)\nexpansion known from effective string models in the continuum limit. Our\nprecision is however still not sufficient to disentangle non-univeral terms of\norder $L_0^{-7}"
    },
    {
        "anchor": "Quantum Chromodynamics with Many Flavors: We investigate the phase structure of lattice QCD for general number of\nflavors $N_F$. Based on numerical data combined with the results of the\nperturbation theory we propose the following picture: When $N_F \\ge 17$, there\nis only one IR fixed point at vanishing gauge coupling, i.e., the theory in the\ncontinuum limit is trivial. On the other hand, when $16 \\ge N_F \\ge 7$, there\nis a non-trivial fixed point. Therefore, the theory is non-trivial with\nanomalous dimensions, however, without quark confinement. Theories which\nsatisfy both quark confinement and spontaneous chiral symmetry breaking in the\ncontinuum limit exist only for $N_F \\le 6$.",
        "positive": "Relevant momentum components of gluons for confinement and chiral\n  symmetry breaking: We investigate which momentum components of gluons induce color confinement\nand spontaneous chiral symmetry breaking in lattice QCD. For this purpose, we\nformulate a lattice framework to introduce the momentum cutoff of the gluon\nfield. Using this framework, we calculate the quark-antiquark potential, the\ncolor flux tube, the chiral condensate, and the Dirac spectrum. Our results\nsuggest that confinement and chiral symmetry breaking are induced by somehow\ndifferent momentum components of gluons."
    },
    {
        "anchor": "Towards Precision B-physics from Non-Perturbative Heavy Quark Effective\n  Theory: We convey an idea of the significant recent progress, which opens up good\nperspectives for high-precision ab-initio computations in heavy flavour physics\nbased on lattice QCD. Rather than surveying the latest results, this\ncontribution focuses on the concept and the challenges of fully\nnon-perturbative computations in the B-meson sector, where the b-quark is\ntreated within an effective theory. We outline its use to determine the b-quark\nmass and report on the results obtained in the quenched approximation and on\nthe status in the two dynamical flavour theory.",
        "positive": "Tensor renormalization group analysis of CP(N-1) model: We apply the higher-order tensor renormalization group to the lattice\nCP($N-1$) model in two dimensions. A tensor network representation of the\nCP($N-1$) model in the presence of the $\\theta$ term is derived. We confirm\nthat the numerical results of the CP(1) model without the $\\theta$ term using\nthis method are consistent with that of the O(3) model which is analyzed by the\nsame method in the region $\\beta \\gg 1$ and that obtained by the Monte Carlo\nsimulation in a wider range of $\\beta$. The numerical computation including the\n$\\theta$ term is left for future challenges."
    },
    {
        "anchor": "Modelling the gluon propagator: Scaling of the Landau gauge gluon propagator calculated at beta=6.0 and at\nbeta=6.2 is demonstrated. A variety of functional forms for the gluon\npropagator calculated on a large (32^3x64) lattice at beta=6.0 are\ninvestigated.",
        "positive": "The QCD equation of state at nonzero densities: lattice result: In this letter we give the equation of state of QCD at finite temperatures\nand densities. The recently proposed overlap improving multi-parameter\nreweighting technique is used to determine observables at nonvanishing chemical\npotentials. Our results are obtained by studying n_f=2+1 dynamical staggered\nquarks with semi-realistic masses on N_t=4 lattices."
    },
    {
        "anchor": "Unexpected Spin-Off from Quantum Gravity: We propose a novel way of investigating the universal properties of spin\nsystems by coupling them to an ensemble of causal dynamically triangulated\nlattices, instead of studying them on a fixed regular or random lattice.\nSomewhat surprisingly, graph-counting methods to extract high- or\nlow-temperature series expansions can be adapted to this case. For the\ntwo-dimensional Ising model, we present evidence that this ameliorates the\nsingularity structure of thermodynamic functions in the complex plane, and\nimproves the convergence of the power series.",
        "positive": "Semileptonic D-decays and Lattice QCD: We explore four different strategies to extract the D-meson semileptonic\ndecay form factors from the Green functions computed in QCD numerically on the\nlattice. From our numerical tests we find that two such strategies, based on\nthe use of double ratios of 3-point correlation functions, lead to an\nappreciable reduction of systematic uncertainties. This is an important step in\nreducing the overall uncertainty in the lattice QCD results for the D-decay\nform factors which are needed to determine the CKM entries |Vcd| and |Vcs|\nexperimentally, that are nowadays known by imposing the unitarity of the CKM\nmatrix."
    },
    {
        "anchor": "Using analytic continuation for the hadronic vacuum polarization\n  computation: We present two examples of applications of the analytic continuation method\nfor computing the hadronic vacuum polarization function in space- and time-like\nmomentum regions. These examples are the Adler function and the leading order\nhadronic contribution to the muon anomalous magnetic moment. We comment on the\nfeasibility of the analytic continuation method and provide an outlook for\npossible further applications.",
        "positive": "Analytic continuation in QCD-like theories at finite density and finite\n  isospin: The method of analytic continuation is one of the most powerful tools to\ncircumvent the sign problem in lattice QCD. The present study is part of a\nlarger project which, based on the investigation of QCD-like theories which are\nfree of the sign problem, is aimed at testing the validity of the method of\nanalytic continuation and at improving its predictivity, in view of its\napplication to real QCD. We have shown that a considerable improvement can be\nachieved if suitable functions are used to interpolate data with imaginary\nchemical potential. We present results obtained in a theory free of the sign\nproblem such as two-color QCD at finite chemical potential."
    },
    {
        "anchor": "Charmonium properties at finite temperature on quenched anisotropic\n  lattices: We study charmonium properties below and above $T_c$ up to 1.8$T_c$, on\nquenched anisotropic lattices. Information of the spectral functions is\nextracted using the maximum entropy method and the constrained curve fitting.\nWe also calculate the color singlet and averaged free energies and evaluate the\ncharmonium spectrum with the potential model analysis. The relation between the\nlattice result of the spectral function analysis and the potential model is\ndiscussed.",
        "positive": "QCD-like technicolor on the lattice: This talk gives an overview, aimed at non-experts, of the recent progress on\nthe studies of technicolor models on the lattice. Phenomenologically successful\ntechnicolor models require walking coupling; thus, an emphasis is put on the\ndetermination of the beta-function of various models. As a case study we\nconsider SU(2) gauge field theory with two adjoint representation fermions,\nso-called minimal walking technicolor theory."
    },
    {
        "anchor": "An Effective Action for Finite Temperature Lattice Gauge Theories with\n  Dynamical Fermions: Dynamical fermions induce via the fermion determinant a gauge-invariant\neffective action. In principle, this effective action can be added to the usual\ngauge action in simulations, reproducing the effects of closed fermion loops.\nUsing lattice perturbation theory at finite temperature, we compute for\nstaggered fermions the one-loop fermionic corrections to the spatial and\ntemporal plaquette couplings as well as the leading $Z_N$ symmetry breaking\ncoupling. A. Hasenfratz and T. DeGrand have shown that $\\beta_c$ for dynamical\nstaggered fermions can be accurately estimated by the formula $\\beta_c =\n\\beta^{\\rm pure}_c - \\Delta\\beta_F$ where $\\Delta\\beta_F$ is the shift induced\nby the fermions at zero temperature. Numerical and analytical results indicate\nthat the finite temperature corrections to the zero-temperature calculation of\nA. Hasenfratz and T. DeGrand are small for small values of $\\kappa = {1\\over\n2m_F}$, but become significant for intermediate values of $\\kappa$. The effect\nof these finite temperature corrections is to ruin the agreement of the\nHasenfratz-DeGrand calculation with Monte Carlo data. We argue, however, that\nthe finite temperature corrections are suppressed nonperturbatively at low\ntemperatures, resolving this apparent disagreement. The $Z_N$ symmetry breaking\ncoupling is small; we argue that it changes the order of the transition while\nhaving little effect on the critical value of $\\beta$.",
        "positive": "On the foundations of partially quenched chiral perturbation theory: It has been widely assumed that partially quenched chiral perturbation theory\nis the correct low-energy effective theory for partially quenched QCD. Here we\npresent arguments supporting this assumption. First, we show that, for\npartially quenched QCD with staggered quarks, a transfer matrix can be\nconstructed. This transfer matrix is not Hermitian, but it is bounded, and it\ncan be used to construct correlation functions in the usual way. Combining\nthese observations with an extension of the Vafa--Witten theorem to the\npartially quenched theory allows us to argue that the partially quenched theory\nsatisfies the cluster property. By extending Leutwyler's analysis of the\nunquenched case to the partially quenched theory, we then conclude that the\nexistence and properties of the transfer matrix as well as clustering are\nsufficient for partially quenched chiral perturbation theory to be the correct\nlow-energy theory for partially quenched QCD."
    },
    {
        "anchor": "Scalar Meson Spectroscopy with Lattice Staggered Fermions: With sufficiently light up and down quarks the isovector ($a_0$) and\nisosinglet ($f_0$) scalar meson propagators are dominated at large distance by\ntwo-meson states. In the staggered fermion formulation of lattice quantum\nchromodynamics, taste-symmetry breaking causes a proliferation of two-meson\nstates that further complicates the analysis of these channels. Many of them\nare unphysical artifacts of the lattice approximation. They are expected to\ndisappear in the continuum limit. The staggered-fermion fourth-root procedure\nhas its purported counterpart in rooted staggered chiral perturbation theory\n(rSXPT). Fortunately, the rooted theory provides a strict framework that\npermits the analysis of scalar meson correlators in terms of only a small\nnumber of low energy couplings. Thus the analysis of the point-to-point scalar\nmeson correlators in this context gives a useful consistency check of the\nfourth-root procedure and its proposed chiral realization. Through numerical\nsimulation we have measured correlators for both the $a_0$ and $f_0$ channels\nin the ``Asqtad'' improved staggered fermion formulation in a lattice ensemble\nwith lattice spacing $a = 0.12$ fm. We analyze those correlators in the context\nof rSXPT and obtain values of the low energy chiral couplings that are\nreasonably consistent with previous determinations.",
        "positive": "In-medium quarkonium properties from a lattice QCD based effective field\n  theory: In order to understand the experimental data on heavy quarkonium production\nin heavy ion collisions at RHIC and LHC it is necessary (though not sufficient)\nto pinpoint the properties of heavy $Q\\bar{Q}$ bound states in the deconfined\nquark-gluon plasma, including their dissolution. Here we present recent results\non the temperature dependence of bottomonium and charmonium correlators, as\nwell as their spectral functions in a lattice QCD based effective field theory\ncalled NRQCD, surveying temperatures close to the crossover transition $140\n{\\rm MeV} < T< 249 {\\rm MeV}$. The spectra are reconstructed based on a novel\nBayesian prescription, whose systematic uncertainties are assessed. We present\nindications for sequential melting of different quarkonium species with respect\nto their vacuum binding energies and give estimates on the survival of S-wave\nand P-wave ground states."
    },
    {
        "anchor": "Quenched Approximation Artifacts: A study in 2-dimensional QED: The spectral properties of the Wilson-Dirac operator in 2-dimensional QED\nresponsible for the appearance of exceptional configurations in quenched\nsimulations are studied in detail. The mass singularity structure of the\nquenched functional integral is shown to be extremely compicated, with multiple\nbranch points and cuts. The connection of lattice topological charge and\nexactly real eigenmodes is explored using cooling techniques. The lattice\nvolume and spacing dependence of these modes is studied, as is the effect of\nclover improvement of the action. A recently proposed modified quenched\napproximation is applied to the study of meson correlators, and the results\ncompared with both naive quenched and full dynamical calculations of the same\nquantity.",
        "positive": "A qubit regularization of asymptotic freedom at the BKT transition\n  without fine-tuning: We propose a two-dimensional hard core loop-gas model as a way to regularize\nthe asymptotically free massive continuum quantum field theory that emerges at\nthe BKT transition. Without fine-tuning, our model can reproduce the universal\nstep-scaling function of the classical lattice XY model in the massive phase as\nwe approach the phase transition. This is achieved by lowering the fugacity of\nFock-vacuum sites in the loop-gas configuration space to zero in the\nthermodynamic limit. Some of the universal quantities at the BKT transition\nshow smaller finite size effects in our model as compared to the traditional XY\nmodel. Our model is a prime example of qubit regularization of an\nasymptotically free massive quantum field theory in Euclidean space-time and\nhelps understand how asymptotic freedom can arise as a relevant perturbation at\na decoupled fixed point without fine-tuning."
    },
    {
        "anchor": "Better than $1/Mflops sustained: a scalable PC-based parallel computer\n  for lattice QCD: We study the feasibility of a PC-based parallel computer for medium to large\nscale lattice QCD simulations. The E\\\"otv\\\"os Univ., Inst. Theor. Phys. cluster\nconsists of 137 Intel P4-1.7GHz nodes with 512 MB RDRAM. The 32-bit, single\nprecision sustained performance for dynamical QCD without communication is 1510\nMflops/node with Wilson and 970 Mflops/node with staggered fermions. This gives\na total performance of 208 Gflops for Wilson and 133 Gflops for staggered QCD,\nrespectively (for 64-bit applications the performance is approximately halved).\nThe novel feature of our system is its communication architecture. In order to\nhave a scalable, cost-effective machine we use Gigabit Ethernet cards for\nnearest-neighbor communications in a two-dimensional mesh. This type of\ncommunication is cost effective (only 30% of the hardware costs is spent on the\ncommunication). According to our benchmark measurements this type of\ncommunication results in around 40% communication time fraction for lattices\nupto 48^3\\cdot96 in full QCD simulations. The price/sustained-performance ratio\nfor full QCD is better than $1/Mflops for Wilson (and around $1.5/Mflops for\nstaggered) quarks for practically any lattice size, which can fit in our\nparallel computer. The communication software is freely available upon request\nfor non-profit organizations.",
        "positive": "QED: Chiral transition and the issue of triviality: I give a review and progress report on studies of lattice QED. I emphasize\nanalytical results and methods that are applied in data analysis. Also, I\nderive some bounds for the critical exponents and establish their connection\nwith scaling violations. Triviality, as realized in $\\phi^4$ theory, is ruled\nout on theoretical grounds. I show that the present data, if analyzed\ncorrectly, all lead to the same conclusions. They are compatible with power law\nscaling with nongaussian exponents."
    },
    {
        "anchor": "Thermodynamical quantities for overlap fermions with chemical potential: Recently a formulation of overlap fermions at finite density based on an\nanalytic continuation of the sign function was proposed. We study this proposal\nby analyzing the energy and number densities for free fermions as a function of\nthe chemical potential and the temperature. Our results show that overlap\nfermions with chemical potential give rise to the correct continuum behavior.",
        "positive": "Baryon Number Correlations in Heavy Ion Collisions: The cross-over region of the quark-gluon plasma (QGP) created in heavy ion\ncollisions is influenced by the nearby deconfinement, chiral and baryon\ncondensation phase transitions. A characteristic signature of the deconfinement\ntransition in this region can be infered using the flux tube model, which is\ndual to the Polyakov loop description and which offers a visual picture of what\nhappens during the transition. The three-point (anti)vertices of a flux tube\nnetwork lead to formation of (anti)baryons upon hadronisation. Since there is\nno fundamental interaction associated with the baryon number, correlations in\nthe baryon number distribution at the last scattering surface directly reflect\nthe preceding pattern of the flux tube vertices in the QGP. An alternating\npattern of vertices and antivertices would lead to an oscillatory signal in the\ntwo-point baryon number correlations, under the experimental conditions\nprevalent in heavy ion collisions at RHIC and LHC. The strength of the\noscillations is a measure of the flexibility of the QGP."
    },
    {
        "anchor": "News from the Lattice: example of the pion distribution amplitude: In this contribution I present a brief summary of recent progress in selected\nLattice QCD techniques and subsequently illustrate them using the example of\nthe current calculations of moments of meson distribution amplitude as well as\nof a direct evaluation of meson distribution amplitude.",
        "positive": "Electric and Magnetic Screening Masses around the Deconfinement\n  Transition: We report on the status of our study of gluon propagators and screening\nmasses around the de- confining transition for pure SU(2) gauge theory in\nLandau gauge."
    },
    {
        "anchor": "The transverse structure of the QCD string: The characterization of the transverse structure of the QCD string is\ndiscussed. We formulate a conjecture as to how the stress-energy tensor of the\nunderlying gauge theory couples to the string degrees of freedom. A consequence\nof the conjecture is that the energy density and the longitudinal-stress\noperators measure the distribution of the transverse position of the string, to\nleading order in the string fluctuations, whereas the transverse-stress\noperator does not. We interpret recent numerical measurements of the transverse\nsize of the confining string and show that the difference of the energy and\nlongitudinal-stress operators is the appropriate probe to use when comparing\nwith the next-to-leading order string prediction. Secondly we derive the\nconstraints imposed by open-closed string duality on the transverse structure\nof the string. We show that a total of three independent `gravitational' form\nfactors characterize the transverse profile of the closed string, and obtain\nthe interpretation of recent effective string theory calculations: the square\nradius of a closed string of length \\beta, defined from the slope of its\ngravitational form factor, is given by (d-1)/(2\\pi\\sigma)\\log(\\beta/(4r_0)) in\nd space dimensions. This is to be compared with the well-known result that the\nwidth of the open-string at mid-point grows as (d-1)/(2\\pi\\sigma) log(r/r_0).\nWe also obtain predictions for transition form factors among closed-string\nstates.",
        "positive": "MILC staggered conjugate gradient performance on Intel KNL: We review our work done to optimize the staggered conjugate gradient (CG)\nalgorithm in the MILC code for use with the Intel Knights Landing (KNL)\narchitecture. KNL is the second gener- ation Intel Xeon Phi processor. It is\ncapable of massive thread parallelism, data parallelism, and high on-board\nmemory bandwidth and is being adopted in supercomputing centers for scientific\nresearch. The CG solver consumes the majority of time in production running, so\nwe have spent most of our effort on it. We compare performance of an MPI+OpenMP\nbaseline version of the MILC code with a version incorporating the QPhiX\nstaggered CG solver, for both one-node and multi-node runs."
    },
    {
        "anchor": "Charmed and light pseudoscalar meson decay constants from HISQ\n  simulations: We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$,\nand the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD. We\nuse the MILC highly improved staggered quark (HISQ) ensembles with four\ndynamical quark flavors. Our primary results are $f_{D^+} =\n212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} =\n249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} =\n1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total\nsystematic, respectively. We also obtain $f_{K^+}/f_{\\pi^+} =\n1.1956(10)({}^{+26}_{-18})$, updating our previous result, and determine the\nquark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and $m_c/m_s =\n11.747(19)({}^{+59}_{-43})$. When combined with experimental measurements of\nthe decay rates, our results lead to precise determinations of the CKM matrix\nelements $|V_{us}| = 0.22487(51) (29)(20)(5)$, $|V_{cd}|=0.217(1) (5)(1)$ and\n$|V_{cs}|= 1.010(5)(18)(6)$, where the errors are from this calculation of the\ndecay constants, the uncertainty in the experimental decay rates,\nstructure-dependent electromagnetic corrections, and, in the case of\n$|V_{us}|$, the uncertainty in $|V_{ud}|$, respectively.",
        "positive": "Chiral Fermions Coupled to Lattice Gauge Fields: Lattice fermions have well-known difficulties with chiral symmetry. To evade\nthem it is possible to couple continuum fermions to lattice gauge fields, by\nintroducing an interpolation of the latter. Following this line of thinking,\nthis paper presents two Euclidean formulations of the effective action that\nappears after functional integration over fermion fields, one for vector-like\nand the other for chiral couplings. With suitable finite-mode regulators both\neffective actions can be evaluated in a finite computation. The prescriptions\nprovided here contain some details not found in previous work marrying\ncontinuum fermions to the lattice via an interpolation. For example, the\ncounter-terms needed to maintain chiral gauge invariance are explicitly given.\nBy construction coupling-constant renormalization, anomaly structure, and (in\nthe chiral gauge theory) fermion nonconserving amplitudes all satisfy one's\nexpectations from perturbative and semi-classical analyses."
    },
    {
        "anchor": "Baryon interactions from lattice QCD with physical masses -- $S=-2$\n  sector --: The strangeness $S=-2$ baryon-baryon interaction is investigated directly\nfrom the fundamental theory of the strong interaction, QCD. The HAL QCD method\nenables us to extract baryon interactions from the Nambu-Bethe-Salpeter wave\nfunctions without using any experimental information. We present our latest\nresult on the $S = -2$ baryon interactions and discuss the H-dibaryon state\nusing potentials which are calculated by using the (almost) physical point\ngauge configurations with large lattice volume of$(8.1{\\rm{fm}})^4$ generated\non the K-computer.",
        "positive": "Testing the threshold expansion for three-particle energies at fourth\n  order in $\u03c6^4$ theory: A relativistic formalism for relating the the energies of the states of three\nscalar particles in finite volume to infinite volume scattering amplitudes has\nrecently been developed. This formalism has been used to predict the energy of\nthe state closest to threshold in an expansion in powers of $1/L$, with $L$ the\nbox length. This expansion has been tested previously by a perturbative\ncalculation of the threshold energy in $\\lambda \\phi^4$ theory, working to\nthird order in $\\lambda$ and up to $\\mathcal O(1/L^6)$ in the volume expansion.\nHowever, several aspects of the predicted threshold behavior do not enter until\nfourth (three-loop) order in perturbation theory. Here I extend the\nperturbative calculation to fourth order and find agreement with the general\nprediction. This check also requires a two-loop calculation of the\ninfinite-volume off-shell two-particle scattering amplitude near threshold. As\na spin-off, I check the threshold expansion for two particles to the same\norder, finding agreement with the result that follows from L\\\"uscher's\nformalism."
    },
    {
        "anchor": "Recent progress in lattice QCD at finite density: We review recent progress in lattice QCD at finite density. The phase diagram\nof QCD and the equation of state at finite temperature and density are\ndiscussed. In particular, we focus on the critical point terminating a first\norder phase transition line in the high density region. The critical point is\none of the most interesting features that may be discovered in heavy-ion\ncollision experiments. We summarize the current discussion on the existence of\na critical point in the QCD phase diagram and discuss some attempts to find the\ncritical point by numerical simulations.",
        "positive": "Confinement by Monopoles in the Positive Plaquette Model of SU(2)\n  Lattice Gauge Theory: Confinement via 't Hooft-Mandelstam monopoles is studied for the positive\nplaquette model in SU(2) lattice gauge theory. Positive plaquette model\nconfigurations are projected into the maximum abelian gauge and the magnetic\ncurrent extracted. The resulting magnetic current is used to compute monopole\ncontributions to Wilson loops and extract a monopole contribution to the string\ntension. As was previously found for the Wilson action, the monopole\ncontribution to the string tension agrees with the string tension calculated\ndirectly from the SU(2) links. The fact that the positive plaquette model\nsuppresses Z2 monopoles and vortices is discussed."
    },
    {
        "anchor": "The Landau gauge gluon propagator at zero and finite temperature:\n  accounting for the combined finite lattice spacing and finite volume effects: In the past years a good comprehension of the infrared gluon propagator has\nbeen achieved, with a good qualitative agreement between lattice results and\nDyson-Schwinger equations. However, lattice simulations have been performed at\nphysical volumes which are close to 20 fm but using a large lattice spacing.\nThe interplay between volume effects and lattice spacing effects has not been\ninvestigated. Here we aim to fill this gap and address how the two effects\nchange the gluon propagator in the infrared region. Furthermore, we provide\ninfinite volume extrapolations which take into account the finite volume and\nfinite lattice spacing. We also report on preliminary results for the gluon\npropagator at finite temperature.",
        "positive": "Very high order lattice perturbation theory for Wilson loops: We calculate perturbative Wilson loops of various sizes up to loop order\n$n=20$ at different lattice sizes for pure plaquette and tree-level improved\nSymanzik gauge theories using the technique of Numerical Stochastic\nPerturbation Theory. This allows us to investigate the behavior of the\nperturbative series at high orders. We observe differences in the behavior of\nperturbative coefficients as a function of the loop order. Up to $n=20$ we do\nnot see evidence for the often assumed factorial growth of the coefficients.\nBased on the observed behavior we sum this series in a model with\nhypergeometric functions. Alternatively we estimate the series in boosted\nperturbation theory. Subtracting the estimated perturbative series for the\naverage plaquette from the non-perturbative Monte Carlo result we estimate the\ngluon condensate."
    },
    {
        "anchor": "Perturbative determination of mass dependent renormalization and\n  improvement coefficients for the heavy-light vector and axial-vector currents\n  with relativistic heavy and domain-wall light quarks: We determine the mass dependent renormalization as well as improvement\ncoefficients for the heavy-light vector and axial-vector currents consisting of\nthe relativistic heavy and the domain-wall light quarks through the standard\nmatching procedure. The calculation is carried out perturbatively at the one\nloop level to remove the systematic error of $O(\\alpha_s (am_Q)^n a\\p)$ as well\nas $O(\\alpha_s (am_Q)^n)$ ($n\\ge$0), where $\\p$ is a typical momentum scale in\nthe heavy-light system. We point out that renormalization and improvement\ncoefficients of the heavy-light vector current agree with those of the\naxial-vector current, thanks to the exact chiral symmetry for the light quark.\nThe results obtained with three different gauge actions, plaquette, Iwasaki and\nDBW2, are presented as a function of heavy quark mass and domain-wall height.",
        "positive": "Determination of the charm quark mass in lattice QCD with $2+1$ flavours\n  on fine lattices: We present a determination of the charm quark mass in lattice QCD with three\nactive quark flavours. The calculation is based on PCAC masses extracted from\n$N_\\mathrm{f}=2+1$ flavour gauge field ensembles at five different lattice\nspacings in a range from 0.087 fm down to 0.039 fm. The lattice action consists\nof the $\\mathrm{O}(a)$ improved Wilson-clover action and a tree-level improved\nSymanzik gauge action. Quark masses are non-perturbatively $\\mathrm{O}(a)$\nimproved employing the Symanzik-counterterms available for this discretisation\nof QCD. To relate the bare mass at a specified low-energy scale with the\nrenormalisation group invariant mass in the continuum limit, we use the\nnon-pertubatively known factors that account for the running of the quark\nmasses as well as for their renormalisation at hadronic scales. We obtain the\nrenormalisation group invariant charm quark mass at the physical point of the\nthree-flavour theory to be $M_\\mathrm{c} = 1486(21)\\,\\mathrm{MeV}$. Combining\nthis result with five-loop perturbation theory and the corresponding decoupling\nrelations in the $\\overline{\\mathrm{MS}}$ scheme, one arrives at a result for\nthe renormalisation group invariant charm quark mass in the four-flavour theory\nof $M_\\mathrm{c}(N_\\mathrm{f}=4) = 1548(23)\\,\\mathrm{MeV}$. In the\n$\\overline{\\mathrm{MS}}$ scheme, and at finite energy scales conventional in\nphenomenology, we quote\n$m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}}(m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}};\nN_\\mathrm{f}=4)=1296(19)\\,\\mathrm{MeV}$ and\n$m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}}(3\\,\\mathrm{GeV};\nN_\\mathrm{f}=4)=1007(16)\\,\\mathrm{MeV}$ for the renormalised charm quark mass"
    },
    {
        "anchor": "A calculation of the $B_{B}$ parameter in the static limit: We calculate the $B_{B}$ parameter, relevant for $\\overline{B}^0$ -- $B^0$\nmixing, from a lattice gauge theory simulation at $\\beta = 6.0$. The bottom\nquarks are simulated in the static theory, the light quarks with Wilson\nfermions. Improved smearing functions produced by a variational technique,\nMOST, are used to reduce statistical errors and minimize excited-state\ncontamination of the ground-state signal. We obtain $B_B(4.33 GeV) =\n0.98^{+4}_{-4}$ (statistical) $^{+3}_{-18}$ (systematic) which corresponds to\n$\\widehat{B}_B = 1.40^{+6}_{-6}$ (statistical) $^{+4}_{-26}$ (systematic) for\nthe one-loop renormalization-scheme-independent parameter. The systematic\nerrors include the uncertainty due to alternative (less favored) treatments of\nthe perturbatively-calculated mixing coefficients; this uncertainty is at least\nas large as residual differences between Wilson-static and clover-static\nresults. Our result agrees with extrapolations of results from relativistic\n(Wilson) heavy quark simulations.",
        "positive": "Dimensional reduction of Lattice Gauge Theory in (2+1)D: This is my Ph.D. thesis defended earlier this year. It contains mostly\ninformation already presented in previous Bielefeld/Saclay papers on this\nsubject, though in more detailed form. It also includes actual calculations and\nsome unpublished material on phase structure of the reduced model."
    },
    {
        "anchor": "The phase transitions in 2D Z(N) vector models for N>4: We investigate both analytically and numerically the renormalization group\nequations in 2D Z(N) vector models. The position of the critical points of the\ntwo phase transitions for N>4 is established and the critical index \\nu\\ is\ncomputed. For N=7, 17 the critical points are located by Monte Carlo\nsimulations and some of the corresponding critical indices are determined. The\nbehavior of the helicity modulus is studied for N=5, 7, 17. Using these and\nother available Monte Carlo data we discuss the scaling of the critical points\nwith N and some other open theoretical problems.",
        "positive": "Finite-Size Scaling of Vector and Axial Current Correlators: Using quenched chiral perturbation theory, we compute the long-distance\nbehaviour of two-point functions of flavour non-singlet axial and vector\ncurrents in a finite volume, for small quark masses, and at a fixed gauge-field\ntopology. We also present the corresponding predictions for the unquenched\ntheory at fixed topology. These results can in principle be used to measure the\nlow-energy constants of the chiral Lagrangian, from lattice simulations in\nvolumes much smaller than one pion Compton wavelength. We show that quenching\nhas a dramatic effect on the vector correlator, which is argued to vanish to\nall orders, while the axial correlator appears to be a robust observable only\nmoderately sensitive to quenching."
    },
    {
        "anchor": "A look inside charmed-strange baryons from lattice QCD: The electromagnetic form factors of the spin-3/2 $\\Omega$ baryons, namely\n$\\Omega$, $\\Omega_c^\\ast$, $\\Omega_{cc}^\\ast$ and $\\Omega_{ccc}$, are\ncalculated in full QCD on $32^3\\times 64$ PACS-CS lattices with a pion mass of\n156(9) MeV. The electric charge radii and magnetic moments from the $E0$ and\n$M1$ multipole form factors are extracted. Results for the electric quadrupole\nform factors, $E2$, are also given. Quark sector contributions are computed\nindividually for each observable and then combined to obtain the baryon\nproperties. We find that the charm quark contributions are systematically\nsmaller than the strange-quark contributions in the case of the charge radii\nand magnetic moments. $E2$ moments of the $\\Omega_{cc}^\\ast$ and $\\Omega_{ccc}$\nprovide a statistically significant data to conclude that their electric charge\ndistributions are deformed to an oblate shape. Properties of the spin-1/2\n$\\Omega_c$ and $\\Omega_{cc}$ baryons are also computed and a thorough\ncomparison is given. This complete study gives valuable hints about the\nheavy-quark dynamics in charmed hadrons.",
        "positive": "Study of the effects of external imaginary electric field and chiral\n  chemical potential on quark matter: The behavior of quark matter with both external electric field and chiral\nchemical potential is theoretically and experimentally interesting to consider.\nIn this paper, the case of simultaneous presence of imaginary electric field\nand chiral chemical potential is investigated using the lattice QCD approach\nwith $N_f=1+1$ dynamical staggered fermions. We find that overall both the\nimaginary electric field and the chiral chemical potential can exacerbate\nchiral symmetry breaking, which is consistent with theoretical predictions.\nHowever we also find a non-monotonic behavior of chiral condensation at\nspecific electric field strengths and chiral chemical potentials. In addition\nto this, we find that the behavior of Polyakov loop in the complex plane is not\nsignificantly affected by chiral chemical potential in the region of the\nparameters consider in this paper."
    },
    {
        "anchor": "Simulation of an Abelian Higgs theory in world line (polymer)\n  representation: In World Line Path Integral representation Abelian Higgs theories admit a\ncurvature term in the Hamiltonian. Using Monte Carlo simulations we show that\nthe curvature term drives a phase transition at sufficiently strong coupling.\nIn quenched approximation this phase transition is smooth, with implications\nthat the model reduces to a Goldstone theory. Critical properties of the system\nnear the transition are investigated and found to be consistent with mean field\nbehavior.",
        "positive": "Improved coarse-graining methods on two dimensional tensor networks\n  including fermions: We show how to apply renormalization group algorithms incorporating\nentanglement filtering methods and a loop optimization to a tensor network\nwhich includes Grassmann variables which represent fermions in an underlying\nlattice field theory. As a numerical test a variety of quantities are\ncalculated for two dimensional Wilson--Majorana fermions and for the two flavor\nGross--Neveu model. The improved algorithms show much better accuracy for\nquantities such as the free energy and the determination of Fisher's zeros."
    },
    {
        "anchor": "Finite Temperature Properties of SO(3) Lattice Gauge Theories and their\n  implications for the continuum limit: It is shown that $SO(3)$ lattice gauge theory on finite size lattices has\nmetastable states related to the ground states of both the bulk transition and\nthe finite temperature transition. The Polyakov line variable in the adjoint\nrepresentation of $SU(2)$ is used to trace the origin of these metastable\nstates. It is also argued that a second order finite temperature transition in\nthe continuum theory is not inconsistent with the first order transition in\n$SO(3)$ lattice gauge theory and the absence of a $Z(2)$ global symmetry.",
        "positive": "Heavy-strange meson decay constants in the continuum limit of quenched\n  QCD: We improve a previous quenched result for heavy-light pseudoscalar meson\ndecay constants with the light quark taken to be the strange quark. A finer\nlattice resolution (a ~ 0.05 fm) in the continuum limit extrapolation of the\ndata computed in the static approximation is included. We also give further\ndetails concerning the techniques used in order to keep the statistical and\nsystematic errors at large lattice sizes L/a under control. Our final result,\nobtained by combining these data with determinations of the decay constant for\npseudoscalar mesons around the D_s, follows nicely the qualitative expectation\nof the 1/m-expansion with a (relative) 1/m-term of about -0.5 GeV/m_PS. At the\nphysical b-quark mass we obtain F_{B_s} = 193(7) MeV, where all errors apart\nfrom the quenched approximation are included."
    },
    {
        "anchor": "Progress on the three-particle quantization condition: We report progress on extending the relativistic model-independent\nquantization condition for three particles, derived previously by two of us, to\na broader class of theories, as well as progress on checking the formalism. In\nparticular, we discuss the extension to include the possibility of 2->3 and\n3->2 transitions and the calculation of the finite-volume energy shift of an\nEfimov-like three-particle bound state. The latter agrees with the results\nobtained previously using non-relativistic quantum mechanics.",
        "positive": "Evolving the COLA software library: COLA is a software library for lattice QCD, written in a combination of\nmodern Fortran and C/C++. Intel and NVIDIA have dominated the HPC domain in the\nyears leading up to the exascale era, but the status quo has changed with the\narrival of Frontier and other AMD-based systems in the supercomputing Top 500.\nSetonix is a next generation HPE Cray EX system hosted at the Pawsey\nSupercomputing Centre in Perth, Australia. Setonix features AMD EPYC CPUs and\nAMD Instinct GPUs. This report describes some of my experiences in evolving\nCOLA to adapt to the current hardware landscape."
    },
    {
        "anchor": "Non-perturbative renormalization for general improved staggered\n  bilinears: We present results for non-perturbative renormalization (NPR) factors for\nstaggered fermion bilinears of arbitrary spin and taste. We use \"covariant\"\nbilinears which transform irreducibly under the lattice translation and\nrotation group, and thus do not mix. We form ~ 30 ratios which have no\nanomalous dimensions, and compare the NPR results to those from 1-loop\nperturbation theory. We also compare the absolute renormalization factors\n(which, in general, do have anomalous dimensions) to 1-loop perturbation\ntheory. We use asqtad and HYP-smeared staggered valence fermions on the coarse\nMILC asqtad lattices.",
        "positive": "Masses and decay constants of $B_c^{(*)}$ mesons with $N_f=2+1+1$\n  twisted mass fermions: We present a preliminary lattice determination of the masses and decay\nconstants of the pseudoscalar and vector mesons $B_c$ and $B_c^*$. Our analysis\nis based on the gauge configurations produced by the European Twisted Mass\nCollaboration with $N_f = 2 + 1 + 1$ flavors of dynamical quarks. We simulated\nat three different values of the lattice spacing and with pion masses as small\nas 210 MeV. Heavy-quark masses are simulated directly on the lattice up to\n$\\sim 3$ times the physical charm mass. The physical b-quark mass is reached\nusing the ETMC ratio method. Our preliminary results are: $M_{B_c} =\n6341\\,(60)$ MeV, $f_{B_c} = 396\\,(12)$ MeV, $M_{B_c^*} / M_{B_c} =\n1.0037\\,(39)$ and $f_{B_c^*} / f_{B_c} = 0.987\\,(7)$."
    },
    {
        "anchor": "Neutron magnetic polarisability with Landau mode operators: The application of a uniform background magnetic field makes standard quark\noperators utilising gauge-covariant Gaussian smearing inefficient at isolating\nthe ground state nucleon at nontrivial field strengths. In the absence of QCD\ninteractions, Landau modes govern the quark energy levels. There is evidence\nthat residual Landau mode effects remain when the strong interaction is turned\non. Here we introduce novel quark operators constructed from the\ntwo-dimensional $U(1)$ Laplacian eigenmodes that describe the Landau levels of\na charged particle on a periodic finite lattice. These eigenmode-projected\nquark operators provide enhanced precision for calculating nucleon energy\nshifts in a magnetic field. Using asymmetric source and sink operators, we are\nable to encapsulate the predominant effects of both the QCD and QED\ninteractions in the interpolating fields for the neutron. The neutron magnetic\npolarizability is calculated using these techniques on the $32^3 \\times 64$\ndynamical QCD lattices provided by the PACS-CS Collaboration. In conjunction\nwith a chiral effective-field theory analysis, we obtain a neutron magnetic\npolarizability of $\\beta^n = 2.05(25)(19) \\times 10^{-4}$ fm$^3$, where the\nnumbers in parentheses describe statistical and systematic uncertainties.",
        "positive": "Quarkonium correlators and spectral functions at zero and finite\n  temperature: We study quarkonium correlators and spectral functions at zero and finite\ntemperature using the anisotropic Fermilab lattice formulation with anisotropy\nxi=2 and 4. To control cutoff effects we use several different lattice\nspacings. The spectral functions were extracted from lattice correlators with\nMaximum Entropy Method based on a new algorithm. We find evidence for the\nsurvival of 1S quarkonium states in the deconfined medium till relatively high\ntemperatures as well as for dissolution of 1P quarkonium states right above the\ndeconfinement temperature."
    },
    {
        "anchor": "Vortex dominance of the 0+ and 2+ glueball mass in SU(2) lattice gauge\n  theory: The c-vortex ensembles are constructed by means of the recently proposed\ncooling method which gradually removes the SU(2)/Z_2 coset fields from the\nSU(2) lattice configurations and which thus reveals the Z_2 vortex vacuum\ntexture. Using Teper's blocking method, the screening masses of the 0+ and the\n2+ glueball is calculated from these vortex ensembles and compared with the\nmasses obtained from full configurations. The masses of either case agree\nwithin the achieved numerical accuracy of 10%. As a byproduct, we find that the\noverlaps of the Teper operators with the glueball wavefunctions are\nsignificantly larger in the case of the c-vortex ensembles.",
        "positive": "Excited Upsilon Radiative Decays: Bottomonium S-wave states were studied using lattice NRQCD. Masses of ground\nand excited states were calculated using multiexponential fitting to a set of\ncorrelation functions constructed using both local and wavefunction-smeared\noperators. Three-point functions for M1 transitions between vector and\npseudoscalar states were computed. Robust signals for transitions involving the\nfirst two excited states were obtained. The qualitative features of the\ntransition matrix elements are in agreement with expectations. The calculated\nvalues of matrix elements for Y(2S) and Y(3S) decay are considerably larger\nthan values inferred from measured decay widths."
    },
    {
        "anchor": "Numerical study of entanglement entropy in SU(2) lattice gauge theory: The entropy of entanglement between a three-dimensional slab of thickness l\nand its complement is studied numerically for four-dimensional SU(2) lattice\ngauge theory. We find a signature of a nonanalytic behavior of the entanglement\nentropy, which was predicted recently for large N_c confining gauge theories in\nthe framework of AdS/CFT correspondence. The derivative of the entanglement\nentropy over l is likely to have a discontinuity at some l = l_c. It is argued\nthat such behavior persists even at finite temperatures, probably turning into\na sort of crossover for temperatures larger than the temperature of the\ndeconfinement phase transition. We also confirm that the entanglement entropy\ncontains quadratically divergent l-independent term, and that the nondivergent\nterms behave as the inverse square of l at small distances.",
        "positive": "Nonrelativistic Bound States in Quantum Field Theory: Nonrelativistic bound states are studied using an effective field theory.\nLarge logarithms in the effective theory can be summed using the velocity\nrenormalization group. For QED, one can determine the structure of the leading\nand next-to-leading order series for the energy, and compute corrections up to\norder alpha^8 ln^3 alpha, which are relevant for the present comparison between\ntheory and experiment. For QCD, one can compute the velocity renormalization\ngroup improved quark potentials. Using these to compute the renormalization\ngroup improved t-tbar production cross-section near threshold gives a result\nwith scale uncertainties of 2%, a factor of 10 smaller than existing fixed\norder calculations."
    },
    {
        "anchor": "Extraction of Hadron Interactions above Inelastic Threshold in Lattice\n  QCD: We propose a new method to extract hadron interactions above inelastic\nthreshold from the Nambu-Bethe-Salpter amplitude in lattice QCD. We consider\nthe scattering such as $A+B\\rightarrow C+D$, where $A,B,C,D$ are names of\ndifferent 1-particle states. An extension to cases where particle productions\noccur during scatterings is also discussed.",
        "positive": "Exponential reduction of the sign problem at finite density in the 2+1D\n  XY model via contour deformations: We study the 2+1 dimensional XY model at nonzero chemical potential $\\mu$ on\ndeformed integration manifolds, with the aim of alleviating its sign problem.\nWe investigate several proposals for the deformations, and considerably improve\non the severity of the sign problem with respect to standard reweighting\napproaches. We present numerical evidence that the reduction of the sign\nproblem is exponential both in $\\mu^2$ and in the spatial volume. We also\npresent a new approach to the optimization procedure based on reweighting, that\nsensibly reduces its computational cost."
    },
    {
        "anchor": "Grassmann higher-order tensor renormalization group approach for\n  two-dimensional strong-coupling QCD: We present a tensor-network approach for two-dimensional strong-coupling QCD\nwith staggered quarks at nonzero chemical potential. After integrating out the\ngauge fields at infinite coupling, the partition function can be written as a\nfull contraction of a tensor network consisting of coupled local numeric and\nGrassmann tensors. To evaluate the partition function and to compute\nobservables, we develop a Grassmann higher-order tensor renormalization group\nmethod, specifically tailored for this model. During the coarsening procedure,\nthe blocking of adjacent Grassmann tensors is performed analytically, and the\ntotal number of Grassmann variables in the tensor network is reduced by a\nfactor of two at each coarsening step. The coarse-site numeric tensors are\ntruncated using higher-order singular value decompositions. The method is\nvalidated by comparing the partition function, the chiral condensate and the\nbaryon density computed with the tensor method with exact analytical results on\nsmall lattices up to volumes of $4\\times4$. For larger volumes, we present\nfirst tensor results for the chiral condensate as a function of the mass and\nvolume, and observe that the chiral symmetry is not broken dynamically in two\ndimensions. We also present tensor results for the number density as a function\nof the chemical potential, which hint at a first-order phase transition.",
        "positive": "Effective Polyakov loop models for QCD-like theories at finite chemical\n  potential: We study genuine finite density effects in QCD-like theories with\nthree-dimensional Polyakov-loop effective theories for heavy quarks. These are\nderived from the full QCD-like theories by combined strong-coupling and hopping\nexpansions. In particular, we investigate the cold and dense regimes of phase\ndiagrams where we expect to find Bose-Einstein-condensation of diquark baryons\nor a fermionic first-order liquid-gas transition, depending on the gauge group\nof the theory. In two-color QCD, for example, we observe evidence of a\ncontinuous zero-temperature transition to finite diquark density when the quark\nchemical potential $\\mu$ reaches half the diquark mass, i.e. without binding\nenergy. In G$_2$-QCD we observe, in addition to this \"Silver Blaze\" onset of\ndiquark density, a second transition in the density towards an exponential\nincrease by roughly $3\\mu/T$ corresponding to a finite density of\nG$_2$-nucleons."
    },
    {
        "anchor": "Nucleon structure with two flavors of dynamical domain-wall fermions: We present a numerical lattice quantum chromodynamics calculation of\nisovector form factors and the first few moments of the isovector structure\nfunctions of the nucleon. The calculation employs two degenerate dynamical\nflavors of domain-wall fermions, resulting in good control of chiral symmetry\nbreaking. Non-perturbative renormalization of the relevant quark currents is\nperformed where necessary. The inverse lattice spacing, $a^{-1}$, is about 1.7\nGeV. We use degenerate up and down dynamical quark masses around 1, 3/4 and 1/2\nthe strange quark mass. The physical volume of the lattice is about\n$(1.9{fm})^3$. The ratio of the isovector vector to axial charges, $g_A/g_V$,\ntrends a bit lower than the experimental value as the quark mass is reduced\ntoward the physical point. We calculate the momentum-transfer dependences of\nthe isovector vector, axial, induced tensor and induced pseudoscalar form\nfactors. The Goldberger-Treiman relation holds at low momentum transfer and\nyields a pion-nucleon coupling, $g_{\\pi NN} = 15.5(1.4)$, where the quoted\nerror is only statistical. We find that the flavor non-singlet quark momentum\nfraction $<x>_{u-d}$ and quark helicity fraction $<x>_{\\Delta u-\\Delta d}$\novershoot their experimental values after linear chiral extrapolation. We\nobtain the transversity, $<1 >_{\\delta u-\\delta d} = 0.93(6)$ in $\\bar{\\rm MS}$\nat 2 GeV and a twist-3 polarized moment, $d_1$, appears small, suggesting that\nthe Wandzura-Wilczek relation holds approximately. We discuss the systematic\nerrors in the calculation, with particular attention paid to finite-volume\neffects, excited-state contamination, and chiral extrapolations.",
        "positive": "Spin-3/2 Baryons in Lattice QCD: We present first results for masses of spin-3/2 baryons in lattice QCD, using\na novel fat-link clover fermion action in which only the irrelevant operators\nare constructed using fat links. In the isospin-1/2 sector, we observe, after\nappropriate spin and parity projection, a strong signal for the J^P=3/2^-\nstate, and find good agreement between the 1/2^+ mass and earlier nucleon mass\nsimulations with a spin-1/2 interpolating field. For the isospin-3/2 Delta\nstates, clear mass splittings are observed between the various 1/2^+/- and\n3/2^+/- channels, with the calculated level orderings in good agreement with\nthose observed empirically."
    },
    {
        "anchor": "Fermions as Global Correction: the QCD Case: It is widely believed that the fermion determinant cannot be treated in\nglobal acceptance-rejection steps of gauge link configurations that differ in a\nlarge fraction of the links. However, for exact factorizations of the\ndeterminant that separate the ultraviolet from the infrared modes of the Dirac\noperator it is known that the latter show less variation under changes of the\ngauge field compared to the former. Using a factorization based on recursive\ndomain decomposition allows for a hierarchical algorithm that starts with pure\ngauge updates of the links within the domains and ends after a number of\nfilters with a global acceptance-rejection step. Ratios of determinants have to\nbe treated stochastically and we construct techniques to reduce the noise. We\nfind that the global acceptance rate is high on moderate lattice sizes and\ndemonstrate the effectiveness of the hierarchical filter.",
        "positive": "The classically perfect fixed point action for SU(3) gauge theory: In this paper (the first of a series) we describe the construction of fixed\npoint actions for lattice $SU(3)$ pure gauge theory. Fixed point actions have\nscale invariant instanton solutions and the spectrum of their quadratic part is\nexact (they are classical perfect actions). We argue that the fixed point\naction is even 1--loop quantum perfect, i.e. in its physical predictions there\nare no $g^2 a^n$ cut--off effects for any $n$. We discuss the construction of\nfixed point operators and present examples. The lowest order $q {\\bar q}$\npotential $V(\\vec{r})$ obtained from the fixed point Polyakov loop correlator\nis free of any cut--off effects which go to zero as an inverse power of the\ndistance $r$."
    },
    {
        "anchor": "The thermodynamic and the continuum limit of meson screening masses: We present results on the thermodynamic and continuum limit of meson\nscreening masses in the deconfined phase, using standard staggered and\nnon-perturbatively clover-improved Wilson fermions in the quenched\napproximation with light quark masses.\n  For two temperatures, 1.5 Tc and 3.0 Tc, it is found that on finite lattices\nscreening masses differ between the actions. We study if both actions reproduce\nthe same masses in the continuum by employing different methods of\nextrapolation to the thermodynamic and continuum limit.",
        "positive": "Non-perturbative QCD: renormalization, O(a)-improvement and matching to\n  Heavy Quark Effective Theory: We give an introduction to three topics in lattice gauge theory:\n  I. The Schroedinger Functional and O(a) improvement.\n  O(a) improvement has been reviewed several times. Here we focus on explaining\nthe basic ideas in detail and then proceed directly to an overview of the\nliterature and our personal assessment of what has been achieved and what is\nmissing.\n  II. The computation of the running coupling, running quark masses and the\nextraction of the renormalization group invariants.\n  We focus on the basic strategy and on the large effort that has been invested\nin understanding the continuum limit. We point out what remains to be done.\n  III. Non-perturbative Heavy Quark Effective Theory.\n  Since the literature on this subject is still rather sparse, we go beyond the\nbasic ideas and discuss in some detail how the theory works in principle and in\npractice."
    },
    {
        "anchor": "Exotic hadronic states and all-to-all quark propagators: We discuss methods to obtain accurate hadronic spectra with propagating\nquarks. Comparing the determination of masses for spin-exotic hybrid mesons\nwith glueball mass determinations, we conclude that quark propagators from all\nsites to all other sites would enable great improvement in the errors. Such\npropagators are achievable by using stochastic estimators. We discuss previous\nattempts and present our method for maximal variance reduction. This is a very\npromising technique and we illustrate it by obtaining the spectrum of ground\nstate and excited B mesons in the limit where the $b$ quark is static.",
        "positive": "Functional Forms for Lattice Correlators at Small Times: The analytic form of the lattice quark propagator is used to derive the\nfunctional form for short distance mesonic correlators. These are then used to\ncalculate ``Continuum Model'' Ansatze which comprise of a pole, representing\nthe ground state, plus a contribution for the excited states, coming from the\nshort distance behaviour. These are compared to Monte Carlo data."
    },
    {
        "anchor": "Complex Langevin: Boundary terms and application to QCD: We employ the Complex Langevin method for simulation of complex-valued\nactions. First, we show how to test for convergence of the method by\nexplicitely computing boundary terms and demonstrate this in a model. Then we\ninvestigate the deconfinement phase transition of QCD with $N_f=2$\nWilson-fermions using the Complex Langevin Method and. We give preliminary\nresults for the transition temperatures up to $\\mu/T_c(\\mu=0)\\approx 5$ and\ncompute the curvature coefficient $\\kappa_2$.",
        "positive": "Nonperturbative Gauge Fixing and Perturbation Theory: We compare the gauge-fixing approach proposed by Jona-Lasinio and Parrinello,\nand by Zwanziger (JPLZ) with the standard Fadeev-Popov procedure, and\ndemonstrate perturbative equality of gauge-invariant quantities, up to\nirrelevant terms induced by the cutoff. We also show how a set of local,\nrenormalizable Feynman rules can be constructed for the JPLZ procedure."
    },
    {
        "anchor": "Distinguishing J=4 from J=0 on a cubic lattice: We discuss the problem of constructing operators of arbitrary continuum\nangular momentum on a spatial lattice. We illustrate one simple approach and\nestimate the lightest J=4 glueball mass in the D=2+1 SU(2) gauge theory.",
        "positive": "The Phase Diagram of the $N=2$ Kazakov-Migdal Model: We have determined the phase diagram of the simplest version of a lattice\nmodel introduced in the recent work of Kazakov and Migdal. If $m_0$ and\n$\\lambda$ are the bare mass and self coupling of the scalar field in the model\nrespectively, we find a line of first order phase transitions in the ($m_0,\n\\lambda$) plane ending in a critical point where $\\lambda$ is nonzero. Kazakov\nand Migdal speculate that their model of scalar field theory could induce QCD.\nOur work indicates that for $N=2$ there is no continuum limit for the\nKazakov-Migdal model except at the critical end point. Whether or not a\nnontrivial continuum limit exists in the vicinity of the critical point\nrequires careful study of the renormalization group properties of the model."
    },
    {
        "anchor": "Controlling sign problems in spin models using tensor renormalization: We consider the sign problem for classical spin models at complex $\\beta\n=1/g_0^2$ on $L\\times L$ lattices. We show that the tensor renormalization\ngroup method allows reliable calculations for larger Im$\\beta$ than the\nreweighting Monte Carlo method. For the Ising model with complex $\\beta$ we\ncompare our results with the exact Onsager-Kaufman solution at finite volume.\nThe Fisher zeros can be determined precisely with the TRG method. We check the\nconvergence of the TRG method for the O(2) model on $L\\times L$ lattices when\nthe number of states $D_s$ increases. We show that the finite size scaling of\nthe calculated Fisher zeros agrees very well with the Kosterlitz-Thouless\ntransition assumption and predict the locations for larger volume. The location\nof these zeros agree with Monte Carlo reweighting calculation for small volume.\nThe application of the method for the O(2) model with a chemical potential is\nbriefly discussed.",
        "positive": "Momentum Lattice Simulation on a Small Lattice Using Stochastic\n  Quantization: We have studied the scalar $\\phi^4$-model in the symmetric phase and the\nnon--compact $U(1)$ gauge theory on a momentum lattice using the Langevin\nequation for generating configurations. In the $\\phi^4$-model we have analyzed\nthe renormalized mass and in the $U(1)$-model we have analyzed the Wilson loop\noperator. We used a second order algorithm for solving the Langevin equation,\nand we looked for the convergence rate of the method. We studied the stochastic\ntime needed to generate equilibrium configurations and compared first and\nsecond order schemes for both models."
    },
    {
        "anchor": "Renormalisation of lattice currents and the calculation of decay\n  constants for dynamical staggered fermions: A numerical calculation of the lattice staggered renormalisation constants at\n$\\beta = 5.35$, $m = 0.01$ is presented. It is seen that there are considerable\nnon-perturbative effects present. As an application the vector decay constant\n$f_\\rho$ is estimated. (LAT92 contribution, one LATEX file with 3 postscript\nfigures appended.)",
        "positive": "Gauge-Higgs Unification on the Lattice: The simplest Gauge-Higgs Unification model is a five-dimensional SU(2) gauge\ntheory compactified on the S^1/Z_2 orbifold, such that on the four-dimensional\nboundaries of space-time there is an unbroken U(1) symmetry and a complex\nscalar, the latter identified with the Higgs boson. Perturbatively the U(1)\nremains spontaneously unbroken. Earlier lattice Monte Carlo simulations\nrevealed however that the spontaneous breaking of the U(1) does occur at the\nnon-perturbative level. Here, we verify the Monte Carlo result via an\nanalytical lattice Mean-Field expansion."
    },
    {
        "anchor": "The nucleon axial-vector coupling beyond one loop: We analyze the nucleon axial-vector coupling to two loops in chiral\nperturbation theory. We show that chiral extrapolations based on this\nrepresentation require lattice data with pion masses below 300 MeV.",
        "positive": "Single quark entropy and the Polyakov loop: We study Quantum Chromodynamics (QCD) with 2+1 flavors with almost physical\nquark masses using the highly improved staggered quark action (HISQ). We\ncalculate the Polyakov loop in a wide temperature range, obtain the free energy\nand the entropy of a single static quark and discuss the QCD crossover region\nin detail. We show that the entropy has a peak close to the chiral crossover\nand consider the consequences for the deconfinement aspects of the crossover\nphenomena. We study the renormalized Polyakov loop susceptibilities and place\nthem into the context of the crossover. We also obtain a quantitative result\nfor the onset of weak coupling behavior at high temperatures."
    },
    {
        "anchor": "Additive and multiplicative renormalization of topological charge with\n  improved gluon/fermion actions: A test case for 3-loop vacuum calculations,\n  using overlap or clover fermions: We calculate perturbative renormalization properties of the topological\ncharge, using the standard lattice discretization given by a product of twisted\nplaquettes. We use the overlap and clover action for fermions, and the Symanzik\nimproved gluon action for 4- and 6-link loops.\n  We compute the multiplicative renormalization of the topological charge\ndensity to one loop; this involves only the gluon part of the action. The power\ndivergent additive renormalization of the topological susceptibility is\ncalculated to 3 loops.\n  Our work serves also as a test case of the techniques and limitations of\nlattice perturbation theory, it being the first 3-loop computation in the\nliterature involving overlap fermions.",
        "positive": "A Single Right-Moving Free Fermion Mode on an Ultra-Local $1+1$d\n  Spacetime Lattice: Defining a Chiral Fermion Theory on a lattice has presented an ongoing\nchallenge both in Condensed Matter physics and in Lattice Gauge Theory. In this\npaper, we demonstrate that a chiral free-fermion theory can live on an\nultra-local spacetime lattice if we allow the Lagrangian to be non-hermitian.\nRather than a violation of unitarity, the non-hermitian structure of our\nLagrangian arises because time is discrete, and we show that our model is obeys\nan elementary unitarity condition: namely, that the norm of the two-point\nfunctions conserves probability. Beyond unitarity, our model displays several\nsurprising properties: it is formulated directly in Minkowskian time; it has\nexactly Lorentz invariant dynamics for all frequencies and momenta (in the\nlarge volume limit); and it is free from all gauge anomalies, despite the\nprediction from field theory that it should suffer one. We show that our model\nis a discrete time description of a single chiral edge mode of several recently\nproposed $2+1$d Floquet models. That the chiral edge can be treated without the\nrest of the $2+1$d system, even when coupled to a gauge field, implies that the\nFloquet models are radically different from Integer Quantum Hall models, which\nalso support chiral edge modes. Furthermore, the Floquet results imply that our\nmodel can be physically realized, which presents an opportunity for gauge\ntheories to be simulated in a condensed matter or cold atom context. Our\nresults present a solution to the `Chiral-fermion problem:' a chiral field\ntheory can indeed be defined on an ultra-local spacetime lattice, and we\naddress how our model avoids several no-go arguments."
    },
    {
        "anchor": "A study of the eta and eta' mesons with improved staggered fermions: We report on a high statistics lattice QCD calculation of the mass of the eta\nand eta' mesons using ASQTAD improved staggered fermions. The calculation used\ntwo ensembles with different lattice spacings and pion masses. We also report\nresults for eta-eta' mixing. The results are in satisfactory agreement with\nother lattice calculations using other fermion formulations and with\nexperiment, given the the unphysical quark masses used. We see no evidence of\nabnormal behaviour at the lattice spacings studied.",
        "positive": "Coloured Polymers: We show that non-oriented coloured polymers (self--avoiding walks with\ndifferent types of links) are in the same universality class of the ordinary\nself--avoiding walks, while the oriented coloured are not."
    },
    {
        "anchor": "Random paths with curvature: We present some results coming from a Monte Carlo simulation of a set of\nrandom paths with a curvature dependent action. This model can be considered as\na toy model of the theory of random surfaces. The transition from free to rigid\nrandom paths has been analyzed and the similitude with the crumpling transition\nhave been pointed out.",
        "positive": "A method to measure the antikaon-nucleon scattering length in lattice\n  QCD: We propose a method to determine the isoscalar \\bar K N scattering length on\nthe lattice. Our method represents the generalization of L\\\"uscher's approach\nin the presence of inelastic channels (complex scattering length). In addition,\nthe proposed approach allows one to find the position of the S-matrix pole\ncorresponding the the Lambda(1405) resonance."
    },
    {
        "anchor": "Towards the phase diagram of dense two-color matter: We study two-color QCD with two flavors of Wilson fermion as a function of\nquark chemical potential mu and temperature T. We find evidence of a superfluid\nphase at intermediate mu and low T where the quark number density and diquark\ncondensate are both very well described by a Fermi sphere of nearly-free quarks\ndisrupted by a BCS condensate. Our results suggest that the quark contribution\nto the energy density is negative (and balanced by a positive gauge\ncontribution), although this result is highly sensitive to details of the\nenergy renormalisation. We also find evidence that the chiral condensate in\nthis region vanishes in the massless limit. This region gives way to a region\nof deconfined quark matter at higher T and mu, with the deconfinement\ntemperature, determined from the renormalised Polyakov loop, decreasing only\nvery slowly with increasing chemical potential. The quark number susceptibility\nchi_q does not exhibit any qualitative change at the deconfinement transition.\nWe argue that this is because chi_q is not an appropriate measure of\ndeconfinement for 2-color QCD at high density.",
        "positive": "Recent Result in QCD Thermodynamics from the Lattice: Recent results on QCD thermodynamics are presented. The nature of the T>0\ntransition is determined, which turns out to be an analytic cross-over. The\nabsolute scale for this transition is calculated. The results were obtained by\nusing a Symanzik improved gauge and stout-link improved fermionic action. In\norder to approach the continuum limit four different sets of lattice spacings\nwere used with temporal extensions N_t=4, 6, 8 and 10 (they correspond to\nlattice spacings a \\sim 0.3, 0.2, 0.15 and 0.12 fm). The equation of state is\ndetermined on N_t=4 and 6 lattices. The importance of the continuum limit for\ndifferent results (critical endpoint, colour superconducting phase) at\nnon-vanishing baryonic densities is discussed."
    },
    {
        "anchor": "The Phase Structure of the Weakly Coupled Lattice Schwinger Model: The weak coupling expansion is applied to the single flavour Schwinger model\nwith Wilson fermions on a symmetric toroidal lattice of finite extent. We\ndevelop a new analytic method which permits the expression of the partition\nfunction as a product of pure gauge expectation values whose zeroes are the\nLee-Yang zeroes of the model. Application of standard finite-size scaling\ntechniques to these zeroes recovers previous numerical results for the small\nand moderate lattice sizes to which those studies were restricted. Our\ntechniques, employable for arbitrarily large lattices, reveal the absence of\naccumulation of these zeroes on the real hopping parameter axis at constant\nweak gauge coupling. The consequence of this previously unobserved behaviour is\nthe absence of a zero fermion mass phase transition in the Schwinger model with\nsingle flavour Wilson fermions at constant weak gauge coupling.",
        "positive": "Leading-order hadronic contributions to the lepton anomalous magnetic\n  moments from the lattice: The hadronic leading-order (hlo) contribution to the lepton anomalous\nmagnetic moments $a_l^\\mathrm{hlo}$ of the Standard Model leptons still\naccounts for the dominant source of the uncertainty of the Standard Model\nestimates. We present the results of an investigation of the hadronic leading\norder anomalous magnetic moments of the electron, muon and tau lepton from\nfirst principles in twisted mass lattice QCD. With lattice data for multiple\npion masses in the range $230 \\mathrm{~MeV} \\lesssim m_{PS} \\lesssim 490\n\\mathrm{~MeV}$, multiple lattice volumes and three lattice spacings we perform\nthe extrapolation to the continuum and to the physical pion mass and check for\nall systematic uncertainties in the lattice calculation. As a result we\ncalculate $a_{l}^\\mathrm{hlo}$ for the three Standard Model leptons with\ncontrolled statistical and systematic error in agreement with phenomenological\ndeterminations using dispersion relations and experimental data. In addition,\nwe also give a first estimate of the hadronic leading order anomalous magnetic\nmoments from simulations directly at the physical value of the pion mass."
    },
    {
        "anchor": "Confinement and the effective string theory in SU(N->oo) : a lattice\n  study: We calculate in the SU(6) gauge theory the mass of the lightest flux loop\nthat winds around a spatial torus, as a function of the torus size, taking care\nto achieve control of the main systematic errors. For comparison we perform a\nsimilar calculation in SU(4). We demonstrate approximate linear confinement and\nshow that the leading correction is consistent with what one expects if the\nflux tube behaves like a simple bosonic string at long distances. We obtain\nsimilar but less accurate results for stable (k-)strings in higher\nrepresentations. We find some evidence that for k>1 the length scale at which\nthe bosonic string correction becomes dominant increases as N increases. We\nperform all these calculations not just for long strings, up to about 2.5`fm'\nin length, but also for shorter strings, down to the minimum length, lc = 1/Tc,\nwhere Tc is the deconfining temperature. We find that the mass of the\nground-state string, at all length scales, is not very far from the simple\nNambu-Goto string theory prediction, and that the fit improves as N increases\nfrom N=4 to N=6. We estimate the mass of the first excited string and find that\nit also follows the Nambu-Goto prediction, albeit more qualitatively. We\ncomment upon the significance of these results for the string description of\nSU(N) gauge theories in the limit of infinite N.",
        "positive": "Coulomb gauge gluon propagator on anisotropic lattices: We calculate the transverse and the time-time components of the Coulomb-gauge\ngluon propagator in SU(3) lattice Yang-Mills theory both on isotropic and\nanisotropic lattices. The problem of scaling violation observed on the\nisotropic lattice is drastically reduced as the anisotropy increases; namely,\nthe system approaches the Hamiltonian limit. In the infrared region, the\ntransverse gluon propagator exhibits a turnover and the temporal gluon\npropagator shows divergent behavior."
    },
    {
        "anchor": "From deep inelastic scattering to heavy-flavor semi-leptonic decays:\n  Total rates into multi-hadron final states from lattice QCD: We present a new technique for extracting decay and transition rates into\nfinal states with any number of hadrons. The approach is only sensitive to\ntotal rates, in which all out-states with a given set of QCD quantum numbers\nare included. For processes involving photons or leptons, differential rates\nwith respect to the non-hadronic kinematics may also be extracted. Our method\ninvolves constructing a finite-volume Euclidean four-point function, whose\ncorresponding spectral function measures the decay and transition rates in the\ninfinite-volume limit. This requires solving the inverse problem of extracting\nthe spectral function from the correlator and also necessitates a smoothing\nprocedure so that a well-defined infinite-volume limit exists. Both of these\nsteps are accomplished by the Backus-Gilbert method and, as we show with a\nnumerical example, reasonable precision can be expected in cases with multiple\nopen decay channels. Potential applications include nucleon structure functions\nand the onset of the deep inelastic scattering regime, as well as semi-leptonic\n$D$ and $B$ decay rates.",
        "positive": "Approaching conformality with the Tensor Renormalization Group method: We discuss the Tensor Renormalization Group (TRG) method for the O(2) model\nwith a chemical potential in 1+1 dimensions with emphasis on near\ngapless/conformal situations. We emphasize the role played by the late Leo\nKadanoff in the development of this theoretical framework. We describe the\nentanglement entropy in the superfluid phase (see arXiv:1507.01471 for\ndetails). We present recent progress on optimized truncation methods."
    },
    {
        "anchor": "Confinement/Deconfinement in 4D compact QED on the lattice: It has long been known that there is a phase transition between confined and\nunconfined phases of compact pure gauge QED on the lattice. In this work we\nreport three manifestations of this phase change as seen in the Landau gauge\nphoton propagator, the static potential, and distribution of Dirac Strings in\nthe gauge fixed configurations. Each of these was calculated with large\nlattices with volumes: $32^4$, $48^4$ and $96^4$. We show that the confined\nphase manifests with a Yukawa type propagator with a dynamically generated mass\ngap, a linearly increasing potential, and a significant concentration of Dirac\nstrings while the unconfined phase appears consistent with the continuum\nresults: a free propagator, a near constant long-distance potential, and a\nsmall concentration of Dirac strings trending towards zero. Furthermore, the\nphoton propagator is investigated in detail near the transition between the two\nphases.",
        "positive": "Anomalous magnetic moment of the muon with dynamical QCD+QED: The current $3.5\\sigma$ discrepancy between experimental and Standard Model\ndeterminations of the anomalous magnetic moment of the muon $a_\\mu=(g-2)/2$ can\nonly be extended to the discovery $5\\sigma$ regime through a reduction of both\nexperimental and theoretical uncertainties. On the theory side, this means a\ndetermination of the hadronic vacuum polarisation (HVP) contribution to better\nthan 0.5%, a level of precision that demands the inclusion of QCD + QED effects\nto properly understand how the behaviour of quarks are modified when their\nelectric charges are turned on. The QCDSF collaboration has generated an\nensemble of configurations with dynamical QCD and QED fields with the specific\naim of studying flavour breaking effects arising from differences in the quark\nmasses and charges in physical quantities. Here we study these effects in a\ncalculation of HVP around the SU(3) symmetric point. Furthermore, by performing\npartially-quenched simulations we are able to cover a larger range of quark\nmasses and charges on these configurations and then fit the results to an SU(3)\nflavour breaking expansion. Subsequently, this allows for an extrapolation to\nthe physical point."
    },
    {
        "anchor": "Nucleon-pion-state contribution to nucleon two-point correlation\n  functions: We study the nucleon-pion-state contribution to the QCD two-point function of\nthe standard nucleon interpolating fields. For sufficiently small quark masses\nthese two-particle states are expected to have a smaller total energy than the\nsingle-particle excited states. We calculate the nucleon-pion-state\ncontribution to leading order in chiral perturbation theory. Both parity\nchannels are considered. We find the nucleon-pion-state contribution to be\nsmall, contributing at the few percent level to the effective mass in the\npositive parity channel.",
        "positive": "Hadron Spectrum and Matrix Elements in QCD with Dynamical Wilson\n  Fermions at 6/g^2=5.3: We present results of a lattice simulation of quantum chromodynamics with two\ndegenerate flavors of dynamic Wilson fermions at $6/g^2=5.3$ at each of two\ndynamical fermion hopping parameters, $\\kappa=0.1670$ and 0.1675, corresponding\nto pion masses in lattice units of about 0.45 and 0.31. The simulations include\nthree other values of valence quark mass, in addition to the dynamical quarks.\nWe present calculations of masses and of the decay constants of vector mesons\nand of pseudoscalars, including the D-meson decay constant. The effects of sea\nquarks on matrix elements and spectroscopy are small."
    },
    {
        "anchor": "Using lattice methods in non-canonical quantum statistics: We define a natural coarse-graining procedure which can be applied to any\nclosed equilibrium quantum system described by a density matrix ensemble and we\nshow how the coarse-graining leads to the Gaussian and canonical ensembles.\nAfter this motivation, we present two ways of evaluating the Gaussian\nexpectation values with lattice simulations. The first one is computationally\ndemanding but general, whereas the second employs only canonical expectation\nvalues but it is applicable only for systems which are almost thermodynamical.",
        "positive": "Meron-Cluster Simulation of the $\u03b8$-Vacuum in the 2-d $O(3)$-Model: The 2-d $O(3)$-model with a $\\theta$-vacuum term is formulated in terms of\nWolff clusters. Each cluster carries a half-integer topological charge. The\nclusters with charge $\\pm 1/2$ are identified as merons. At $\\theta = \\pi$ the\nmerons are bound in pairs inducing a second order phase transition at which the\nmass-gap vanishes. The construction of an improved estimator for the\ntopological charge distribution makes numerical simulations of the phase\ntransition feasible. The measured critical exponents agree with those of the $k\n= 1$ Wess-Zumino-Novikov-Witten model. Our results are consistent with\nHaldane's conjecture for 1-d antiferromagnetic quantum spin chains."
    },
    {
        "anchor": "$\u03b1_s$ from the Lattice Hadronic Vacuum Polarisation: We present a determination of the QCD coupling constant, $\\alpha_s$, obtained\nby fitting lattice results for the flavour $ud$ hadronic vacuum polarisation\nfunction to continuum perturbation theory. We use $n_f=2+1$ flavours of Domain\nWall fermions generated by the RBC/UKQCD collaboration and three lattice\nspacings $a^{-1}=1.79,\\, 2.38$ and $3.15\\ \\text{GeV}$. Several sources of\npotential systematic error are identified and dealt with. After fitting and\nremoving expected leading cut-off effects, we find for the five-flavour\n$\\overline{\\text{MS}}$ coupling the value\n$\\alpha_s(M_Z)=0.1181(27)^{+8}_{-22}$, where the first error is statistical and\nthe second systematic.",
        "positive": "Disconnected contributions to D-meson semi-leptonic decay form factors: We calculate the disconnected contribution to the form factor for the\nsemileptonic decay of a D-meson into a final state, containing a flavor singlet\neta meson. We use QCDSF n_f=2+1 configurations at the flavor symmetric point\nm_u=m_d=m_s and the partially quenched approximation for the relativistic charm\nquark. Several acceleration and noise reduction techniques for the stochastic\nestimation of the disconnected loop are tested."
    },
    {
        "anchor": "A novel quark-field creation operator construction for hadronic physics\n  in lattice QCD: A new quark-field smearing algorithm is defined which enables efficient\ncalculations of a broad range of hadron correlation functions. The technique\napplies a low-rank operator to define smooth fields that are to be used in\nhadron creation operators. The resulting space of smooth fields is small enough\nthat all elements of the reduced quark propagator can be computed exactly at\nreasonable computational cost. Correlations between arbitrary sources,\nincluding multi hadron operators can be computed a posteriori without requiring\nnew lattice Dirac operator inversions. The method is tested on realistic\nlattice sizes with light dynamical quarks.",
        "positive": "Reply to M.Campostrini's and P.Rossi's Comment on our paper\n  `Nonuniformity of the $1/N$ Expansion for Two-Dimensional $O(N)$ Models': This reply tries to rectify some misunderstandings that are in our opinion\ncontained in the Comment by Campostrini and Rossi, <hep-lat 99407008> on our\npaper <hep-lat 9407003>."
    },
    {
        "anchor": "Two-photon decay of the neutral pion in lattice QCD: We perform non-perturbative calculation of the \\pi^0 to {\\gamma}{\\gamma}\ntransition form factor and the associated decay width using lattice QCD. The\namplitude for two-photon final state, which is not an eigenstate of QCD, is\nextracted through an Euclidean time integral of the relevant three-point\nfunction. We utilize the all-to-all quark propagator technique to carry out\nthis integral as well as to include the disconnected quark diagram\ncontributions. The overlap fermion formulation is employed on the lattice to\nensure exact chiral symmetry on the lattice. After examining various sources of\nsystematic effects except for possible discretization effect, we obtain\n\\Gamma=7.83(31)(49) eV for the pion decay width, where the first error is\nstatistical and the second is our estimate of the systematic error.",
        "positive": "Quark flavor decomposition of the nucleon axial form factors: We present results on the isoscalar form factors including the disconnected\ncontributions, as well as on the strange and charm quark form factors. Using\nprevious results on the isovector form factors, we determine the flavor\ndecomposition of the nucleon axial form factors. These are computed using an\nensemble of $N_f=2+1+1$ twisted mass fermions simulated with physical values of\nquark masses. We investigate the SU(3) flavor symmetry and show that there is\nup to 10\\% breaking for the axial and up to 50\\% for the induced pseudoscalar\nform factors. By fitting the $Q^2$-dependence, we determined the corresponding\nroot mean square radii. The pseudoscalar coupling of the $\\eta$ meson and the\nnucleon is found to be $g_{\\eta NN}=3.7(1.0)(0.7)$, and the Goldberger-Treiman\ndiscrepancy for the octet combination about 50\\%."
    },
    {
        "anchor": "D- and B-Meson Semi-Leptonic Decays: Recent results for semi-leptonic decays of $D$ and $B$ mesons at $\\beta=6.4$,\nusing the Wilson action, and at $\\beta=6.0$, using the Clover action, are\nreported.",
        "positive": "Spectral sum from Euclidean lattice correlators and determination of\n  renormalization constants: We propose a new method to renormalize lattice operators. The method is based\non the technique to compute the spectral sum appearing in the\nShifman-Vainshtein-Zakharov QCD sum rule from lattice correlators. The\napplication of this technique to the light quark system is useful for operator\nrenormalization as well as for the test of perturbative QCD and OPE. We\ndetermine the renormalization constant of the vector current and discuss\nextensions to other current operators."
    },
    {
        "anchor": "The Yang-Mills gradient flow and SU(3) gauge theory with 12 massless\n  fundamental fermions in a colour-twisted box: We perform the step-scaling investigation of the running coupling constant,\nusing the gradient-flow scheme, in SU(3) gauge theory with twelve massless\nfermions in the fundamental representation. The Wilson plaquette gauge action\nand massless unimproved staggered fermions are used in the simulations. Our\nlattice data are prepared at high accuracy, such that the statistical error for\nthe renormalised coupling, g_GF, is at the subpercentage level. To investigate\nthe reliability of the continuum extrapolation, we employ two different lattice\ndiscretisations to obtain g_GF. For our simulation setting, the corresponding\ngauge-field averaging radius in the gradient flow has to be almost half of the\nlattice size, in order to have this extrapolation under control. We can\ndetermine the renormalisation group evolution of the coupling up to g^2_GF ~ 6,\nbefore the onset of the bulk phase structure. In this infrared regime, the\nrunning of the coupling is significantly slower than the two-loop perturbative\nprediction, although we cannot draw definite conclusion regarding possible\ninfrared conformality of this theory. Furthermore, we comment on the issue\nregarding the continuum extrapolation near an infrared fixed point. In addition\nto adopting the fit ansatz a'la Symanzik for performing this task, we discuss a\npossible alternative procedure inspired by properties derived from low-energy\nscale invariance at strong coupling. Based on this procedure, we propose a\nfinite-size scaling method for the renormalised coupling as a means to search\nfor infrared fixed point. Using this method, it can be shown that the behaviour\nof the theory around g^2_GF ~ 6 is still not governed by possible infrared\nconformality.",
        "positive": "Lattice results on charmonium: Recent lattice QCD results on charmonium spectroscopy are reviewed."
    },
    {
        "anchor": "Study of the complex fermion determinant in a $\\rm U(1)_L \\otimes\n  U(1)_R$ symmetric Yukawa model: Lattice theories that contain chiral multiplets of fermions can have complex\nfermion determinants. This is for example the case for the $\\rm U(1)_L \\otimes\nU(1)_R$ symmetric Yukawa model with mirror fermions, if the number of\ngenerations of fermions and mirror fermions is odd. Whether a numerical\nsimulation of such a model is possible depends on the magnitude of fluctuations\nof the complex phase factor of the fermion determinant. We investigate the\nfermion determinant of the U(1) Yukawa model with mirror fermions for a\nphysically relevant choice of parameters. The argument of the complex phase\nturns out to fluctuate only very little and is at most of the order of $2 \\cdot\n10^{-3}$.",
        "positive": "Role of center vortices in chiral symmetry breaking in SU(3) gauge\n  theory: We study the behavior of the AsqTad quark propagator in Landau gauge on SU(3)\nYang-Mills gauge configurations under the removal of center vortices. In SU(2)\ngauge theory, center vortices have been observed to generate chiral symmetry\nbreaking and dominate the infrared behavior of the quark propagator. In\ncontrast, we report a weak dependence on the vortex content of the gauge\nconfigurations, including the survival of dynamical mass generation on\nconfigurations with vanishing string tension."
    },
    {
        "anchor": "Crystalline Confinement: We show that exotic phases arise in generalized lattice gauge theories known\nas quantum link models in which classical gauge fields are replaced by quantum\noperators. While these quantum models with discrete variables have a\nfinite-dimensional Hilbert space per link, the continuous gauge symmetry is\nstill exact. An efficient cluster algorithm is used to study these exotic\nphases. The $(2+1)$-d system is confining at zero temperature with a\nspontaneously broken translation symmetry. A crystalline phase exhibits\nconfinement via multi-stranded strings between charge-anti-charge pairs. A\nphase transition between two distinct confined phases is weakly first order and\nhas an emergent spontaneously broken approximate $SO(2)$ global symmetry. The\nlow-energy physics is described by a $(2+1)$-d $\\mathbb{R}P(1)$ effective field\ntheory, perturbed by a dangerously irrelevant $SO(2)$ breaking operator, which\nprevents the interpretation of the emergent pseudo-Goldstone boson as a dual\nphoton. This model is an ideal candidate to be implemented in quantum\nsimulators to study phenomena that are not accessible using Monte Carlo\nsimulations such as the real-time evolution of the confining string and the\nreal-time dynamics of the pseudo-Goldstone boson.",
        "positive": "The electric dipole moment of the neutron from $N_f=2+1+1$ twisted mass\n  fermions: We extract the neutron electric dipole moment (nEDM) $ \\vert \\vec{d}_n \\vert\n$ on configurations produced with $N_f=2+1+1$ twisted mass fermions with\nlattice spacing of $a \\simeq 0.082$ fm and a light quark mass that corresponds\nto $M_{\\pi} \\simeq 373$ MeV. We do so by evaluating the $CP$-odd form factor\n$F_3$ for small values of the $CP$-violation parameter $\\theta$ in the limit of\nzero momentum transfer. This limit is extracted using the usual parametrization\nbut in addition position space methods. The topological charge is computed via\ncooling and gradient flow using the Wilson, Symanzik tree-level improved and\nIwasaki actions for smoothing. We obtain consistent results for all choices of\nsmoothing procedures and methods to extract $F_3$ at zero momentum transfer.\nFor the ensemble analyzed we find a value of nEDM of $\\vert \\vec{d}_n \\vert /\n\\theta = -0.045(6)(1) {\\rm e} \\cdot {\\rm fm}$."
    },
    {
        "anchor": "Finite-Density Monte Carlo Calculations on Sign-Optimized Manifolds: We present a general technique for addressing sign problems that arise in\nMonte Carlo simulations of field theories. This method deforms the domain of\nthe path integral to a manifold in complex field space that maximizes the\naverage sign (therefore reducing the sign problem) within a parameterized\nfamily of manifolds. We presents results for the $1+1$ dimensional Thirring\nmodel with Wilson fermions on lattice sizes up to $40\\times 10$. This method\nreaches higher $\\mu$ then previous techniques while substantially decreasing\nthe computational time required.",
        "positive": "Charm quark effects on the strong coupling extracted from the static\n  force: We compute the fermionic contribution to the strong coupling $\\alpha_{qq}$\nextracted from the static force in Lattice QCD up to order $g^4$ in\nperturbation theory. This allows us to subtract the leading fermionic lattice\nartifacts from recent determinations of $\\alpha_{qq}$ produced in simulations\nof two dynamical charm quarks. Moreover, by using a suitable parametrization of\nthe $\\beta_{qq}$-function, we can evaluate the charm loop effects on\n$\\alpha_{qq}$ in the continuum limit."
    },
    {
        "anchor": "Weak low-energy couplings from topological zero-mode wavefunctions: We discuss a new method to determine the low-energy couplings of the $\\Delta\nS=1$ weak Hamiltonian in the $\\epsilon$-regime. It relies on a matching of the\ntopological poles in $1/m^2$ of three-point functions of two pseudoscalar\ndensities and a four-fermion operator computed in lattice QCD, to the same\nobservables in the Chiral Effective Theory. We present the results of a NLO\ncomputation in chiral perturbation theory of these correlation functions\ntogether with some preliminary numerical results.",
        "positive": "Mass estimates of the SU(2) $0^{++}$ glueball from spectral methods: The estimation of the K\\\"all\\'en-Lehmann spectral density from gauge\ninvariant lattice QCD two point correlation functions is proposed, and explored\nvia an inversion strategy based on Tikhonov regularisation. We test the method\non a mesonic toy model, showing that our methodology is competitive with the\ntraditional Maximum Entropy Method. As proof of concept the SU(2) glueball\nspectrum for the quantum numbers $J^{PC}=0^{++}$ is investigated, for various\nvalues of the lattice spacing, using the published data of arXiv:1910.07756.\nOur estimates for the ground state mass are in good agreement with the\ntraditional approach, which is based on the large time exponential behaviour of\nthe correlation functions. Furthermore, the spectral density also contains\nhints of excites states in the spectrum. Spectroscopic analysis of glueball\ntwo-point functions therefore provides a straightforward and insightful\nalternative to the traditional method based on the large time exponential\nbehaviour of the correlation functions."
    },
    {
        "anchor": "Free energy of an SU(2) monopole-antimonopole pair: We induce an external ${Z}_2$ monopole-antimonopole pair in an SU(2) lattice\ngauge system and measure its free energy as a way to probe the vacuum\nstructure. We discuss the motivation and computational methodology of the\ninvestigation and illustrate our preliminary results.",
        "positive": "Quark masses, the Dashen phase, and gauge field topology: The CP violating Dashen phase in QCD is predicted by chiral perturbation\ntheory to occur when the up-down quark mass difference becomes sufficiently\nlarge at fixed down-quark mass. Before reaching this phase, all physical\nhadronic masses and scattering amplitudes are expected to behave smoothly with\nthe up-quark mass, even as this mass passes through zero. In Euclidean space,\nthe topological susceptibility of the gauge fields is positive at positive\nquark masses but diverges to negative infinity as the Dashen phase is\napproached. A zero in this susceptibility provides a tentative signal for the\npoint where the mass of the up quark vanishes. I discuss potential ambiguities\nwith this determination."
    },
    {
        "anchor": "Operator product expansion and the short distance behavior of 3-flavor\n  baryon potentials: The short distance behavior of baryon-baryon potentials defined through\nNambu-Bethe-Salpeter wave functions is investigated using the operator product\nexpansion. In a previous analysis of the nucleon-nucleon case, corresponding to\nthe SU(3) channels $27_s$ and $\\overline{10}_a$, we argued that the potentials\nhave a repulsive core. A new feature occurs for the case of baryons made up of\nthree flavors: manifestly asymptotically attractive potentials appear in the\nsinglet and octet channels. Attraction in the singlet channel was first\nindicated by quark model considerations, and recently been found in numerical\nlattice simulations. The latter have however not yet revealed asymptotic\nattraction in the octet channels; we give a speculative explanation for this\napparent discrepancy.",
        "positive": "Lattice chiral symmetry, CP-violation and Majorana fermions: A brief summary of lattice fermions defined by the general Ginsparg-Wilson\nalgebra is first given. It is then shown that those general class of fermion\noperators have a conflict with CP invariance in chiral gauge theory and with\nthe definition of Majorana fermions in the presence of chiral-symmetric Yukawa\ncouplings. The same conclusion holds for the domain-wall fermion also."
    },
    {
        "anchor": "Infrared physics of the 3D SU(2) adjoint Higgs model at the crossover\n  transition: We study the crossover phase transition of the SU(2) Georgi-Glashow model in\nthree dimensions. In this model, a confining condensate of topological 't\nHooft-Polyakov monopoles exists in the Higgs regime. We use lattice Monte Carlo\nsimulations to study the monopole gas across a crossover transition, and\ndemonstrate that gradient flow can be used to renormalize the otherwise\ndivergent monopole number density. The condensation of the monopoles means that\nthe theory admits also a massive photon-like excitation. We show that the\nrenormalized monopole number density is approximately proportional to the\nsquare of the photon mass, in agreement with semiclassical results. Our results\ngive insight into behaviour of the Higgs regime near crossover, which has\nboarder implications for beyond the Standard Model theories containing adjoint\nscalar fields.",
        "positive": "Phase diagram of QCD with four quark flavors at finite temperature and\n  baryon density: We analyze the phase diagram of QCD with four staggered flavors in the (mu,\nT) plane using a method recently proposed by us. We explore the region T > 0.7\nTc and mu <1.4 Tc, where Tc is the transition temperature at zero baryon\ndensity, and find a first order transition line. Our results are quantitatively\ncompatible with those obtained with the imaginary chemical potential approach\nand the double reweighting method, in the region where these approaches are\nreliable, T > 0.9 Tc and mu < Tc. But, in addition, our method allows us to\nextend the transition line to lower temperatures and higher chemical\npotentials."
    },
    {
        "anchor": "Study of Cullum's and Willoughby's Lanczos method for Wilson fermions: The Lanczos method of Cullum and Willoughby is studied for euclidean Wilson\nfermions in quenched and unquenched SU(2) gauge fields on lattices of volume\nranging from $4^4$ to $16^4$. The method is reliable even on larger lattices,\nbut its cost for the computation of a given fraction of the spectrum grows\n(approximately) with the square of the lattice volume. We investigate the\nconvergence behaviour and show that it is closely linked with the local\nspectral density. Complete spectra are determined on lattices up to $8^3 \\cdot\n12$. For configurations where all eigenvalues are computed, we give numerical\nvalues for the fermionic determinants and results for spectral densities.\nDeterminants are also given for staggered fermions whose quenched and\nunquenched spectra were studied in a previous publication.",
        "positive": "The Isgur Wise function from the Lattice: We derive the form factors relevant for decays of pseudo-scalar mesons\ncorresponding to the semi-leptonic decay B->D l nu. The simulations are\nperformed in the quenched approximation at beta=6.0 and beta=6.2 using a\nnon-perturbatively improved clover action. The slope of the Isgur Wise function\nand |Vcb| are extracted from the form factors."
    },
    {
        "anchor": "Non-Perturbative Bounds for Semileptonic Decays in Lattice QCD: We present a new method aiming at a non-perturbative, model-independent\ndetermination of the momentum dependence of the form factors entering\nsemileptonic decays using unitarity and analyticity constraints. We extend the\noriginal proposal and, using suitable two-point functions computed\nnon-perturbatively, we determine the form factors at low-momentum transfer\n$q^2$ from those computed explicitly on the lattice at large $q^2$, without\nmaking any assumption about their $q^2$ dependence. As a training ground we\napply the new method to the analysis of the lattice data of the semileptonic $D\n\\rightarrow K \\ell \\nu_{\\ell}$ decays obtained both at finite values of the\nlattice spacing and at the physical pion point in the continuum limit. We show\nthat, starting from a limited set of data at large $q^2$, it is possible to\ndetermine quite precisely the form factors in a model independent way in the\nfull kinematical range, obtaining a remarkable agreement with the direct\ncalculation of the form factors. This finding opens the possibility to obtain\nnon-perturbatively the form factors entering the semileptonic B decays in the\nfull kinematical range.",
        "positive": "The Microscopic Twisted Mass Dirac Spectrum: The microscopic spectral density for lattice QCD with two flavors and\nmaximally twisted mass is computed. The results are given for fixed index of\nthe Dirac operator and include the leading order $a^2$ corrections to the\nchiral Lagrangian due to the discretization errors. The computation is carried\nout within the framework of Wilson chiral perturbation theory."
    },
    {
        "anchor": "Lattice Models of Quantum Gravity: Standard Regge Calculus provides an interesting method to explore quantum\ngravity in a non-perturbative fashion but turns out to be a CPU-time demanding\nenterprise. One therefore seeks for suitable approximations which retain most\nof its universal features. The $Z_2$-Regge model could be such a desired\nsimplification. Here the quadratic edge lengths $q$ of the simplicial complexes\nare restricted to only two possible values $q=1+\\epsilon\\sigma$, with\n$\\sigma=\\pm 1$, in close analogy to the ancestor of all lattice theories, the\nIsing model. To test whether this simpler model still contains the essential\nqualities of the standard Regge Calculus, we study both models in two\ndimensions and determine several observables on the same lattice size. In order\nto compare expectation values, e.g. of the average curvature or the Liouville\nfield susceptibility, we employ in both models the same functional integration\nmeasure. The phase structure is under current investigation using mean field\ntheory and numerical simulation.",
        "positive": "Continuum extrapolation of quarkonium correlators at non-zero\n  temperature: In the investigation of in-medium modifications of quarkonia and for\ndetermining heavy quark diffusion coefficients, correlation functions play a\ncrucial role. For the first time we perform a continuum extrapolation of\ncharmonium and bottomonium correlators in the vector channel based on\nnon-perturbatively clover-improved Wilson fermions in quenched lattice QCD.\nCalculations were done at 4 different lattice spacings, spatial extents between\n96 and 192, aspect ratio from 1/6 to 1/2, for 5 temperatures between $T/T_c =\n0.75$ and $T/T_c = 2.2$. We interpolate between different quark masses to match\nto the same vector meson mass over different lattice setups. Afterwards we\nextrapolate the renormalized correlators to the continuum. While we find a\nstrong temperature dependence for charmonium, bottomonium states are only\nslightly affected at higher temperatures."
    },
    {
        "anchor": "B to rho ell nu form factors in lattice QCD: We present results from quenched lattice QCD for the form factors for the\ndecay $B\\to\\rho l\\nu$. The calculations are performed using a nonperturbatively\nimproved action and operators at two values of the lattice spacing. The bottom\nquark mass is reached by extrapolation from simulations performed with heavy\nquark masses around the charm mass. Our primary result is for the partially\nintegrated decay rate $\\Gamma_{PI}$ over the range $12.7\\gev^2 < q^2 <\n18.2\\gev^2$:\n  \\Gamma_PI = (4.9^{+12}_{-10}{+0}_{-14}) X 10^12 s^-1",
        "positive": "Lattice evidence for the family of decoupling solutions of Landau gauge\n  Yang-Mills theory: We show that the low-momentum behavior of the lattice Landau-gauge gluon and\nghost propagators is sensitive to the lowest non-trivial eigenvalue (\\lambda_1)\nof the Faddeev-Popov operator. If the gauge fixing favors Gribov copies with\nsmall \\lambda_1 the ghost dressing function rises more rapidly towards zero\nmomentum than on copies with large \\lambda_1. This effect is seen for momenta\nbelow 1 GeV, and interestingly also for the gluon propagator at momenta below\n0.2 GeV: For large \\lambda_1 the gluon propagator levels out to a lower value\nat zero momentum than for small \\lambda_1. For momenta above 1 GeV no\ndependence on Gribov copies is seen. Although our data is only for a single\nlattice size and spacing, a comparison to the corresponding (decoupling)\nsolutions from the DSE/FRGE study of Fischer, Maas and Pawlowski [Annals of\nPhysics 324 (2009) 2408] yields already a good qualitative agreement."
    },
    {
        "anchor": "Baryon-Baryon Potentials on the Lattice: The interaction of spatially extended heavy baryons is investigated in the\nframework of lattice QCD with dynamical quarks. It is shown that the expected\ndipole forces have a very short range and that the baryon-antibaryon\ninteraction is more attractive than the baryon-baryon interaction. Sea quarks\nplay a minor important role.",
        "positive": "The continuum limit of $f_B$ from the lattice in the static\n  approximation: We present an analysis of the continuum extrapolation of $f_B$ in the static\napproximation from lattice data. The method described here aims to uncover the\nsystematic effects which enter in this extrapolation and has not been described\nbefore. Our conclusions are that we see statistical evidence for scaling of\n$f_B^{stat}$ for inverse lattice spacings $\\gtap 2$ GeV but not for $\\ltap 2$\nGeV. We observe a lack of {\\em asymptotic} scaling for a variety of quantities,\nincluding $f_B^{stat}$, at all energy scales considered. This can be associated\nwith finite lattice spacing systematics. Once these effects are taken into\naccount, we obtain a value of 230(35) MeV for $f_B^{stat}$ in the continuum\nwhere the error represents uncertainties due to both the statistics and the\ncontinuum extrapolation. In this method there is no error due to uncertainties\nin the renormalization constant connecting the lattice and continuum effective\ntheories."
    },
    {
        "anchor": "Violation of chirality of the M\u00f6bius domain-wall Dirac operator from\n  the eigenmodes: We investigate the effects of the violation of the Ginsparg-Wilson (GW)\nrelation in the M\\\"obius domain-wall fermion formulation on the lattice with\nfinite fifth dimension. Using a decomposion in terms of the eigenmodes of its\nfour-dimensional effective Dirac operator, we isolate the GW-violating terms\nfor various physical quantities including the residual mass and the meson\nsusceptibilities relevant for the effective restoration of the axial U(1)\nsymmetry at finite temperature. Numerical result shows that the GW-violating\neffect is more significant, or even overwhelming, for the quantities that are\ndominated by the low-lying eigenmodes.",
        "positive": "Thermal mass and dispersion relations of quarks in the deconfined phase\n  of quenched QCD: Temporal quark correlation functions are analyzed in quenched lattice QCD for\ntwo values of temperature above the critical temperature (Tc) for\ndeconfinement, T=1.5Tc and 3Tc. A two-pole ansatz for the quark spectral\nfunction is used to determine the bare quark mass and the momentum dependence\nof excitation spectra on large lattices of size up to 128^3x16. The dependence\nof the quark correlator on these parameters as well as the finite volume\ndependence of the excitation energies are analyzed in detail in order to\nexamine the reliability of our analysis. Our results suggest the existence of\nquasi-particle peaks in the quark spectrum. We furthermore find evidence that\nthe dispersion relation of the plasmino mode has a minimum at non-zero momentum\neven in the non-perturbative region near Tc. We also elaborate on the\nenhancement of the quark correlator near the chiral limit which is observed at\nT=1.5Tc on about half of the gauge configurations. We attribute this to the\npresence of near zero-modes of the fermion matrix that are associated with\nnon-trivial topology of the gauge configurations."
    },
    {
        "anchor": "(2+1)D SU(2) Yang-Mills Lattice Gauge Theory at finite density via\n  tensor networks: We numerically simulate a non-Abelian lattice gauge theory in two spatial\ndimensions, with Tensor Networks (TN). We focus on the SU(2) Yang-Mills model\nin Hamiltonian formulation, with dynamical matter and minimally truncated gauge\nfield (hardcore gluon). Thanks to the TN sign-problem-free approach, we\ncharacterize the phase diagram of the model at zero and finite baryon number as\na function of the quark bare mass and color charge. Already at intermediate\nsystem sizes, we distinctly detect a liquid phase of quark-pair bound-state\nquasi-particles (baryons), whose mass is finite towards the continuum limit.\nInteresting phenomena arise at the transition boundary where color-electric and\ncolor-magnetic terms are maximally frustrated: for low quark masses, we see\ntraces of potential deconfinement, while for high masses, signatures of a\npossible topological order.",
        "positive": "Tunneling and the Spectrum of the Potts Model: The three-dimensional, three-state Potts model is studied as a paradigm for\nhigh temperature quantum chromodynamics. In a high statistics numerical\nsimulation using a Swendson-Wang algorithm, we study cubic lattices of\ndimension as large as $64^3$ and measure correlation functions on long lattices\nof dimension $20^2\\times 120$ and $30^2\\times 120$. These correlations are\ncontrolled by the spectrum of the transfer matrix. This spectrum is studied in\nthe vicinity of the phase transition. The analysis classifies the spectral\nlevels according to an underlying $S_3$ symmetry. Near the phase transition the\nspectrum agrees nicely with a simple four-component hamiltonian model. In the\ncontext of this model, we find that low temperature ordered-ordered interfaces\nnearly always involve a disordered phase intermediate. We present a new\nspectral method for determining the surface tension between phases."
    },
    {
        "anchor": "$\u03b8$-dependence in the small-$N$ limit of $2d$ $CP^{N-1}$ models: We present a systematic numerical study of $\\theta$-dependence around\n$\\theta=0$ in the small-$N$ limit of $2d$ $CP^{N-1}$ models, aimed at\nclarifying the possible presence of a divergent topological susceptibility in\nthe continuum limit. We follow a twofold strategy, based on one side on direct\nsimulations for $N = 2$ and $N = 3$ on lattices with correlation lengths up to\n$O(10^2)$, and on the other side on the small-$N$ extrapolation of results\nobtained for $N$ up to $9$. Based on that, we provide conclusive evidence for a\nfinite topological susceptibility at $N = 3$, with a continuum estimate $\\xi^2\n\\chi = 0.110(5)$. On the other hand, results obtained for $N = 2$ are still\ninconclusive: they are consistent with a logarithmically divergent continuum\nextrapolation, but do not yet exclude a finite continuum value, $\\xi^2 \\chi\n\\sim 0.4$, with the divergence taking place for $N$ slightly below 2 in this\ncase. Finally, results obtained for the non-quadratic part of\n$\\theta$-dependence, in particular for the so-called $b_2$ coefficient, are\nconsistent with a $\\theta$-dependence matching that of the Dilute Instanton Gas\nApproximation at the point where $\\xi^2 \\chi$ diverges.",
        "positive": "Equilibrium criterion and effective spin models for finite temperature\n  gauge theories: Using the example of the SU(2) gauge theory in 3+1 dimensions we consider the\nconstruction of a 3-dimensional effective model in terms of Polyakov loops. We\ndemonstrate the application of an equilibrium self-consistency condition to the\nsystematic analysis of the contribution of various (global Z(2) symmetric)\nterms in the effective model action. We apply this analysis to the construction\nof a simple effective action with the minimum necessary number of operators.\nSuch an action is shown to be capable of reproducing relevant observables, e.g.\nthe Polyakov loop ensemble average, within the desired accuracy."
    },
    {
        "anchor": "Angular momentum content of the rho-meson in lattice QCD: The variational method allows one to study the mixing of interpolators with\ndifferent chiral transformation properties in the non-perturbatively determined\nphysical state. It is then possible to define and calculate in a\ngauge-invariant manner the chiral as well as the partial wave content of the\nquark-antiquark component of a meson in the infrared, where mass is generated.\nUsing a unitary transformation from the chiral basis to the LSJ basis one may\nextract a partial wave content of a meson. We present results for the ground\nstate of the rho-meson using quenched simulations as well as simulations with\ntwo dynamical quarks, all for lattice spacings close to 0.15 fm. We point out\nthat these results indicate a simple 3S1-wave composition of the rho-meson in\nthe infrared, like in the SU(6) flavor-spin quark model.",
        "positive": "Glueballs and k-strings in SU(N) gauge theories : calculations with\n  improved operators: We test a variety of blocking and smearing algorithms for constructing\nglueball and string wave-functionals, and find some with much improved overlaps\nonto the lightest states. We use these algorithms to obtain improved results on\nthe tensions of k-strings in SU(4), SU(6), and SU(8) gauge theories. We\nemphasise the major systematic errors that still need to be controlled in\ncalculations of heavier k-strings, and perform calculations in SU(4) on an\nanisotropic lattice in a bid to minimise one of these. All these results point\nto the k-string tensions lying part-way between the `MQCD' and `Casimir\nScaling' conjectures, with the power in 1/N of the leading correction lying in\n[1,2]. We also obtain some evidence for the presence of quasi-stable strings in\ncalculations that do not use sources, and observe some near-degeneracies\nbetween (excited) strings in different representations. We also calculate the\nlightest glueball masses for N=2, ...,8, and extrapolate to N=infinity,\nobtaining results compatible with earlier work. We show that the N=infinity\nfactorisation of the Euclidean correlators that are used in such mass\ncalculations does not make the masses any less calculable at large N."
    },
    {
        "anchor": "Heavy quark propagators with improved precision using domain\n  decomposition: We show that, in four dimensions, the quark propagator is affected by\nround-off errors for large values of the quark mass am and the time extent T/a\neven when double precision arithmetics is used to compute it. We introduce a\ndefinition of the solver residual which is sensitive to the problem and apply a\nSchwarz alternating procedure to compute the propagator in a number of\nsub-domains in the time direction. The effectiveness of the method is\ndemonstrated in a numerical computation of the free one-dimensional Dirac\npropagator.",
        "positive": "Thermodynamics of strongly interacting plasma with high accuracy: The equation of state of $SU(3)$ Yang-Mills theory is investigated in the\nframework of a moving reference frame. Results for the entropy density, the\npressure, the energy density, and the trace anomaly are presented for\ntemperatures ranging from 0 to 230 $T_c$, with $T_c$ the deconfinement\ntemperature. The entropy density is the primary observable that has been\nmeasured and form which the other thermodynamic quantities are obtained. At\nleast 4 different values of the lattice spacing have been considered at each\nphysical temperature in order to extrapolate to the continuum limit. The final\naccuracy is 0.5%, increasing to about 1% close to the phase transition. A\ndetailed comparison with the results available in the literature is discussed."
    },
    {
        "anchor": "The Schr\u00f6dinger functional in QCD: The Schr\\\"odinger functional in Wilson's lattice QCD leads to a sensible\nclassical continuum theory which can be taken as starting point for a\nperturbative analysis. In dimensional regularization, the saddle point\nexpansion of the Schr\\\"odinger functional is performed to one-loop order of\nperturbation theory. The divergences are partly cancelled by the usual coupling\nconstant and quark mass renormalization. An additional divergence can be\nabsorbed in a multiplicative renormalization of the quark boundary fields. The\ncorresponding boundary counterterm being a local polynomial in the fields we\nconfirm the general expectation expressed by Symanzik~\\cite{Symanzik}.",
        "positive": "Charmonium-nucleon potential from lattice QCD: We present results for charmonium-nucleon potential $V_{c\\bar{c}-N}(r)$ from\nquenched lattice QCD, which is calculated from the equal-time Bethe-Salpeter\namplitude through the effective Schr\\\"odinger equation. Detail information of\nthe low-energy interaction between the nucleon and charmonia ($\\eta_c$ and\n$J/\\psi$) is indispensable for exploring the formation of charmonium bound to\nnuclei. Our simulations are performed at a lattice cutoff of $1/a\\approx 2.1$\nGeV in a spatial volume of $(3 fm)^3$ with the nonperturbatively $O(a)$\nimproved Wilson action for the light quarks and a relativistic heavy quark\naction for the charm quark. We have found that the potential\n$V_{c\\bar{c}-N}(r)$ for either the $\\eta_c$ and $J/\\psi$ states is weakly\nattractive at short distances and exponentially screened at large distances.\nThe spin averaged $J/\\psi$-$N$ potential is slightly more attractive than that\nof the $\\eta_c$-$N$ case."
    },
    {
        "anchor": "Multi-scale methods in quantum field theory: Daubechies wavelets are used to make an exact multi-scale decomposition of\nquantum fields. For reactions that involve a finite energy that take place in a\nfinite volume, the number of relevant quantum mechanical degrees of freedom is\nfinite. The wavelet decomposition has natural resolution and volume truncations\nthat can be used to isolate the relevant degrees of freedom. The application of\nflow equation methods to construct effective theories that decouple coarse and\nfine scale degrees of freedom is examined.",
        "positive": "SU(3) glueballs on coarse, anisotropic lattices: Results from a calculation of the low-lying glueball spectrum of pure-gauge\nSU(3) are used as a test of the effectiveness of improved discretisation\nschemes in reducing finite spacing errors. Glueball masses are extracted from\nsimulations on anisotropic lattices, where the temporal lattice spacing is much\nshorter than the spatial ones. This allows clearer resolution of the decay of\nglueball correlators."
    },
    {
        "anchor": "Light-Quark FLIC Fermion Simulations of the $1^{-+}$ Exotic Meson: We investigate the mass of the $1^{-+}$ exotic meson, created with hybrid\ninterpolating fields. Access to light quark masses approaching 25 MeV is\nfacilitated by the use of the Fat-Link Irrelevant Clover (FLIC) fermion action,\nand large ($20^3 \\times 40$) lattices. Our results indicate that the $1^{-+}$\nexotic exhibits significant curvature close to the chiral limit, and yield a\n$1^{-+}$ mass in agreement with the $\\pi_1 (1600)$ candidate and exclusive of\nthe $\\pi_1 (1400)$.",
        "positive": "$f_B$ quenched and unquenched: Results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$, and their ratios are\npresented. High statistics quenched runs at $\\beta=5.7$, $5.85$, $6.0$, and\n$6.3$, plus a run still in progress at $\\beta=6.52$ make possible a preliminary\nextrapolation to the continuum. The data allows good control of all systematic\nerrors except for quenching, although not all of the error estimates have been\nfinalized. Results from configurations which include effects of dynamical\nquarks show a significant deviation from the quenched results and make possible\na crude estimate of the quenching error."
    },
    {
        "anchor": "The deconfining phase transition in D=2+1 SU(N) gauge theories: We study the deconfining transition of SU(N) gauge theories in 2+1 dimensions\nfor N ranging between N=2 and N=8. We confirm that the transition is second\norder for N<4 and first order for N>4. For the more delicate case of SU(4) all\nour evidence points to the transition being weakly first order. After\nextrapolating to the continuum limit, we obtain a deconfining temperature that\ncan be well fitted by Tc/sqrt(sigma) = 0.9026(23) + 0.880(43)/N^2 for all N.",
        "positive": "The Nambu--Jona-Lasinio Model of QCD on the Lattice: In an effort to investigate some of the low energy properties of QCD, in\nparticular those related to chiral symmetry breaking, as well as to obtain\ninsights on the behavior of an interacting theory of fermions on the lattice,\nthe two flavor Nambu--Jona-Lasinio model with $SU(2) \\times SU(2)$ chiral\nsymmetry is studied on the four--dimensional hypercubic lattice using large $N$\ntechniques and numerical simulations. Naive and Wilson fermions are considered\nand transparent results are obtained regarding the following: the scalar and\npseudoscalar spectrum, the approach to the continuum and chiral limits, the\nsize of the $1/N$ corrections, and the effects of the zero momentum fermionic\nmodes on finite lattices. Also, some interesting observations are made by\nviewing the model as an embedding theory of the Higgs sector. Note: The full ps\nfile of this preprint is also available via anonymous ftp to ftp.scri.fsu.edu.\nTo get the ps file, ftp to this address and use for username \"anonymous\" and\nfor password your name. The file is in the directory pub/vranas (to go to that\ndirectory type: cd pub/vranas) and is called NJL.ps (to get it type: get\nNJL.ps)"
    },
    {
        "anchor": "Structure and Flow of the Nucleon Eigenstates in Lattice QCD: A determination of the excited energy eigenstates of the nucleon,\n$s=c{1}{2}$, $I={1}{2}$, $N^{\\pm}$, is presented in full QCD using 2+1 flavor\nPACS-CS gauge configurations. The correlation-matrix method is used and is\nbuilt using standard nucleon interpolators employing smearings at the fermion\nsources and sinks. We develop and demonstrate a new technique that allows the\neigenvectors obtained to be utilized to track the propagation of the intrinsic\nnature of energy-states from one quark mass to the next. This approach is\nparticularly useful for larger dimension correlation matrices where more\nnear-degenerate energy-states can appear in the spectrum.",
        "positive": "Lattice Quark Propagator in Landau and Laplacian Gauges: We present results for the lattice quark propagator in both Landau and\nLaplacian gauges using standard and improved staggered quark actions. The\nstandard Kogut-Susskind action has errors of \\oa{2} while the improved\n``Asqtad'' action has \\oa{4}, \\oag{2}{2} errors. This improvement is seen in\nthe quark propagator. We demonstrate the application of tree-level corrections\nto these actions and see that Landau and Laplacian gauges produce very similar\nresults."
    },
    {
        "anchor": "Semileptonic form factors D to pi, K and B to pi, K from a fine lattice: We extract the form factors relevant for semileptonic decays of D and B\nmesons from a relativistic computation on a fine lattice in the quenched\napproximation. The lattice spacing is a=0.04 fm (corresponding to a^{-1}=4.97\nGeV), which allows us to run very close to the physical B meson mass, and to\nreduce the systematic errors associated with the extrapolation in terms of a\nheavy quark expansion. For decays of D and D_s mesons, our results for the\nphysical form factors at q^2=0 are as follows: f_+^{D to pi}(0)= 0.74(6)(4),\nf_+^{D to K}(0)= 0.78(5)(4) and f_+^{D_s to K}(0)=0.68(4)(3). Similarly, for B\nand B_s we find: f_+^{B to pi}(0)=0.27(7)(5), f_+^{B to K}(0)=0.32(6)(6) and\nf_+^{B_s to K}(0)=0.23(5)(4). We compare our results with other quenched and\nunquenched lattice calculations, as well as with light-cone sum rule\npredictions, finding good agreement.",
        "positive": "Clover improvement for stout-smeared 2+1 flavour SLiNC fermions:\n  non-perturbative results: We discuss an action in which the fermion matrix has single level stout\nsmearing for the hopping terms together with unsmeared links for the clover\nterm. With the (tree level) Symanzik improved gluon action this constitutes the\nStout Link Non-perturbative Clover or SLiNC action. To cancel O(a) terms the\nclover coefficient, csw, has to be tuned. We present here preliminary results\nof a non-perturbative determination of csw using the Schrodinger functional and\nas a by-product also a determination of the critical hopping parameter. A\ndetermination of the renormalisation constant for the local vector current is\nalso given. Comparisons of the results are made with lowest order perturbation\ntheory results."
    },
    {
        "anchor": "Calculation of weak matrix elements in domain-wall QCD with the DBW2\n  gauge action: We report the details of our ongoing quenched calculations of weak matrix\nelements using the combination of domain-wall fermions and the DBW2 gauge\naction on lattices with $a^{-1}\\approx 3$ GeV. A strategy to avoid the problem\nof fixed topological charge is introduced in generating gauge configurations.\nAfter studying the basic run parameters and elemental quantities, we present a\npreliminary result for the kaon B-parameter ($B_K$).",
        "positive": "The dual Meissner effect in SU(2) Landau gauge: The dual Meissner effect is observed without monopoles in quenched SU(2) QCD\nwith Landau gauge-fixing. Abelian as well as non-Abelian electric fields are\nsqueezed. Magnetic displacement currents which are time-dependent Abelian\nmagnetic fields play a role of solenoidal currents squeezing Abelian electric\nfields. Monopoles are not always necessary to the dual Meissner effect. The\nsqueezing of the electric flux means the dual London equation and the\nmassiveness of the Abelian electric fields as an asymptotic field. The mass\ngeneration of the Abelian electric fields is related to a gluon condensate\n$<A^a_{\\mu}A^a_{\\mu}>\\neq 0$ of mass dimension 2."
    },
    {
        "anchor": "The S, U and \u0394\u03c1parameters in the Zaragoza proposal for lattice\n  chiral gauge fermions: Using the Zaragoza proposal for lattice chiral gauge fermions, the S, U and\n\\Delta\\rho parameters have been calculated at one loop. It is shown that the\ncontinuum values for these quantities can be reproduced without requiring\nexplicit fine tuning of counterterms. Furthermore, fermion fields doubling is\nnot necessary. To the best of our knowledge, the Zaragoza proposal is the only\nscheme which has these properties. A necessary (although not sufficient)\nsymmetry is found to support the calculations. Previous results for some of\nthese parameters in other lattice chiral regularizations are revisited in the\nlight of this symmetry.",
        "positive": "The Phases of Non-Compact QED(3): Non-compact three-dimensional QED is studied by computer simulations to\nunderstand its chiral symmetry breaking features for different values of the\nnumber of fermion flavors N_f. We consider the four-component formulation for\nthe fermion fields, which arises naturally as the continuum limit of the\nstaggered fermion construction in (2+1) dimensions. We present preliminary\nresults for the equation of state of the theory in an effort to understand the\nproperties of the chiral phase transition of the theory at a critical number of\nfermion flavors N_{fc}. Our preliminary results indicate that N_{fc}~1.5."
    },
    {
        "anchor": "Spectrum Results with Kogut-Susskind Quarks: I summarize recent developments in spectrum calculations using Kogut-Susskind\nquarks. Theoretical developments include one-loop computations with improved\nactions. I present some recent simulation results, mostly from a MILC\ncollaboration project using three flavors. Effects of dynamical quarks are\nclearly seen in the isovector 0++ meson propagator and in the mass ratio ``J''.",
        "positive": "Chiral measurements in quenched lattice QCD with Fixed Point fermions: We construct a parametrization of a Fixed Point (FP) Dirac operator and apply\nit in quenched lattice QCD. The symmetry requirements for a general lattice\nDirac operator are discussed and an efficient way to make a practical\nconstruction of general lattice Dirac operators is provided. We use such a\nlattice Dirac operator to approximately solve the Renormalization Group\nequation that defines the FP Dirac operator in an iterative procedure. We\ndiscuss the properties of this parametrization and show that its breaking of\nchiral symmetry and its scaling violations in hadron specroscopy are much\nreduced compared to the Wilson Dirac operator. Furthermore, we discuss the\noverlap construction with the parametrized FP Dirac operator and its\nproperties. Using the Atiyah-Singer index theorem, a consequence of chiral\nsymmetry, we calculate the quenched topological susceptibility. Finally, we\ndetermine the renormalized low-energy constant Sigma of quenched Chiral\nPerturbation Theory using a finite volume scaling technique."
    },
    {
        "anchor": "Improved lattice computation of proton decay matrix elements: We present an improved result of lattice computation of the proton decay\nmatrix elements in $N_f=2+1$ QCD. In this study, the significant improvement of\nstatistical accuracy by adopting the error reduction technique of\nAll-mode-averaging, is achieved for relevant form factor to proton (and also\nneutron) decay on the gauge ensemble of $N_f=2+1$ domain-wall fermions in\n$m_\\pi=0.34$--0.69 GeV on 2.7~fm$^3$ lattice as used in our previous work\n\\cite{Aoki:2013yxa}. We improve total accuracy of matrix elements to 10--15\\%\nfrom 30--40\\% for $p\\rightarrow\\pi e^+$ or from 20--40\\% for $p\\rightarrow K\n\\bar\\nu$. The accuracy of the low energy constants $\\alpha$ and $\\beta$ in the\nleading-order baryon chiral perturbation theory (BChPT) of proton decay are\nalso improved. The relevant form factors of $p\\rightarrow \\pi$ estimated\nthrough the \"direct\" lattice calculation from three-point function appear to be\n1.4 times smaller than those from the \"indirect\" method using BChPT with\n$\\alpha$ and $\\beta$. It turns out that the utilization of our result will\nprovide a factor 2--3 larger proton partial lifetime than that obtained using\nBChPT. We also discuss the use of these parameters in a dark matter model.",
        "positive": "Hadronic light-by-light contribution to $(g-2)_\u03bc$ from lattice QCD\n  with SU(3) flavor symmetry: We perform a lattice QCD calculation of the hadronic light-by-light\ncontribution to $(g-2)_\\mu$ at the SU(3) flavor-symmetric point\n$m_\\pi=m_K\\simeq 420\\,$MeV. The representation used is based on\ncoordinate-space perturbation theory, with all QED elements of the relevant\nFeynman diagrams implemented in continuum, infinite Euclidean space. As a\nconsequence, the effect of using finite lattices to evaluate the QCD four-point\nfunction of the electromagnetic current is exponentially suppressed. Thanks to\nthe SU(3)-flavor symmetry, only two topologies of diagrams contribute, the\nfully connected and the leading disconnected. We show the equivalence in the\ncontinuum limit of two methods of computing the connected contribution, and\nintroduce a sparse-grid technique for computing the disconnected contribution.\nThanks to our previous calculation of the pion transition form factor, we are\nable to correct for the residual finite-size effects and extend the tail of the\nintegrand. We test our understanding of finite-size effects by using gauge\nensembles differing only by their volume. After a continuum extrapolation based\non four lattice spacings, we obtain $a_\\mu^{\\rm hlbl} = (65.4\\pm 4.9 \\pm\n6.6)\\times 10^{-11}$, where the first error results from the uncertainties on\nthe individual gauge ensembles and the second is the systematic error of the\ncontinuum extrapolation. Finally, we estimate how this value will change as the\nlight-quark masses are lowered to their physical values."
    },
    {
        "anchor": "Spectral reconstruction of Euclidean correlator moments in lattice QCD: A novel application of lattice QCD spectral reconstruction is presented, in\nwhich euclidean correlation function data in a fixed time range are used to\ninfer values outside the range, enabling a model-independent investigation of\nthe asymptotic large-time behavior. Moments of the correlator are also\ndetermined, and reconstructed correlation matrices between different moments\nare included in a variational optimization similar to the standard Generalized\nEigenvalue Problem (GEVP). These ideas are illustrated using a single-nucleon\ncorrelation function determined on an $N_{\\rm}=2+1$ ensemble of gauge\nconfigurations at $m_{\\pi} = 200{\\rm MeV}$.",
        "positive": "Duals of lattice Abelian models with static determinant at finite\n  density: Dual formulations of Abelian U(1) and Z(N) LGT with a static fermion\ndeterminant are constructed at finite temperatures and non-zero chemical\npotential. The dual form is valid for a broad class of lattice gauge actions,\nfor arbitrary number of fermion flavors and in any dimension. The distinguished\nfeature of the dual formulation is that the dual Boltzmann weight is strictly\npositive. This allows to gain reliable results at finite density via the Monte\nCarlo simulations. As a byproduct of the dual representation we outline an\nexact solution for the partition function of the (1 + 1)-dimensional theory and\nreveal an existence of a phase with oscillating correlations."
    },
    {
        "anchor": "An Analysis of Four-quark Energies in SU(2) Lattice Monte Carlo using\n  the Flux-tube Symmetry:: Energies of four-quark systems calculated by the static quenched SU(2)\nlattice Monte Carlo method are analyzed in $2\\times 2$ bases for square,\nrectangle, tilted rectangle, linear and quadrilateral geometry configurations\nand in $3\\times 3$ bases for a non-planar geometry configuration. For small\ninterquark distances, a lattice effect is taken into account by considering\nperimeter dependent terms which are characterized by the cubic symmetry. It is\nthen found that a parameter $f$ - that can be identified as a gluon field\noverlap factor - is rather well described by the form $exp(-[b_sE{\\cal\nA}+\\sqrt{b_s}F{\\cal P}])$, where ${\\cal A}$ and ${\\cal P}$ are the area and\nperimeter mainly defined by the positions of the four quarks, $b_s$ is the\nstring constant in the 2-quark potentials and $E,F$ are constants.",
        "positive": "Tuning HMC using Poisson brackets: We discuss how the integrators used for the Hybrid Monte Carlo (HMC)\nalgorithm not only approximately conserve some Hamiltonian $H$ but exactly\nconserve a nearby shadow Hamiltonian (\\tilde H), and how the difference $\\Delta\nH \\equiv \\tilde H - H $ may be expressed as an expansion in Poisson brackets.\nBy measuring average values of these Poisson brackets over the equilibrium\ndistribution $\\propto e^{-H}$ generated by HMC we can find the optimal\nintegrator parameters from a single simulation. We show that a good way of\ndoing this in practice is to minimize the variance of $\\Delta H$ rather than\nits magnitude, as has been previously suggested. Some details of how to compute\nPoisson brackets for gauge and fermion fields, and for nested and force\ngradient integrators are also presented."
    },
    {
        "anchor": "$B_s\\to D_s \\ell\u03bd$ Form Factors for the full $q^2$ range from Lattice\n  QCD with non-perturbatively normalized currents: We present a lattice QCD determination of the $B_s \\to D_s \\ell\\nu$ scalar\nand vector form factors over the full physical range of momentum transfer. The\nresult is derived from correlation functions computed using the Highly Improved\nStaggered Quark (HISQ) formalism, on the second generation MILC gluon ensembles\naccounting for up, down, strange and charm contributions from the sea. We\ncalculate correlation functions for three lattice spacing values and an array\nof unphysically light $b$-quark masses, and extrapolate to the physical value.\nUsing the HISQ formalism for all quarks means that the lattice current coupling\nto the $W$ can be renormalized non-perturbatively, giving a result free from\nperturbative matching errors for the first time. Our results are in agreement\nwith, and more accurate than, previous determinations of these form factors.\nFrom the form factors we also determine the ratio of branching fractions that\nis sensitive to violation of lepton universality: $R(D_s) = \\mathcal{B}(B_s\\to\nD_s \\tau \\nu_{\\tau})/\\mathcal{B}(B_s\\to D_s \\ell \\nu_{l})$, where $\\ell$ is an\nelectron or a muon. We find $R(D_s) = 0.2987(46)$, which is also more accurate\nthan previous lattice QCD results. Combined with a future measurement of\n$R(D_s)$, this could supply a new test of the Standard Model. We also compare\nthe dependence on heavy quark mass of our form factors to expectations from\nHeavy Quark Effective Theory.",
        "positive": "Exploring the QCD phase diagram with three flavors of M\u00f6bius domain\n  wall fermions: We present an update on the study of the QCD phase transition with 3 flavors\nof M\\\"obius domain wall fermions at zero baryon density. We performed\nsimulations on lattices of size $36^3\\times12\\times16$ and\n$24^3\\times12\\times32$ with a variety of quark masses at a fixed lattice\nspacing $a=0.1361(20)$ fm, which correspond to a temperature 121(2) MeV. By\nanalyzing the chiral condensate, chiral susceptibilitities and Binder cumulant\non $36^3\\times12\\times16$ lattices together with the result obtained from our\nprevious study on $24^3\\times12\\times16$ lattices, we identified a crossover\noccurring at quark mass around $m_q^{\\mathrm{\\overline {MS}}}(2\\, \\mathrm{GeV})\n\\sim 3-4$ MeV for this temperature. Besides, we show the effects of residual\nchiral symmetry breaking on chiral condensate and chiral susceptibilities\nbetween $L_s=16$ and 32."
    },
    {
        "anchor": "Inclusive semi-leptonic $B_{(s)}$ mesons decay at the physical $b$ quark\n  mass: We address the non-perturbative calculation of the decay rate of inclusive\nsemi-leptonic $B_{(s)}$ mesons decays from lattice QCD. Precise theoretical\nStandard Model predictions are key ingredients in searches for new physics.\nThis type of computation may eventually provide new insight into the\nlong-standing tension between the inclusive and exclusive determinations of the\nCKM matrix elements $|V_{cb}|$ and $|V_{ub}|$. We perform a pilot lattice\ncomputation for $B_s \\rightarrow X_c \\, l \\nu_l$ and improve on existing\ntechniques. The valence-quark masses in our simulations are approximately\nphysical for the domain-wall strange and charm quarks as well as for the bottom\nquark, for which we use a relativistic heavy quark effective action. We report\non our progress and discuss future plans towards a first study with fully\ncontrolled systematic effects.",
        "positive": "$\u03c7_{\\textrm{top}}(T \\gg T_{\\textrm{c}})$ in pure-glue QCD through\n  reweighting: We calculate the topological susceptibility at 2.5 Tc and 4.1 Tc in SU(3)\npure Yang-Mills theory. We define topology with the help of gradient flow and\nwe largely overcome the problem of poor statistics at high temperatures by\napplying a reweighting technique in terms of the topological charge, measured\nafter a specific small amount of gradient flow. This allows us to obtain a\nsample of configurations which compares topological sectors with good\nstatistics, with enhanced tunneling between topologies. We quote continuum\nextrapolated results at these two temperatures and conclude that our method is\nviable and can be extended without new conceptual problems to the case of full\nQCD with fermions."
    },
    {
        "anchor": "Efficient Cluster Algorithm for CP(N-1) Models: Despite several attempts, no efficient cluster algorithm has been constructed\nfor CP(N-1) models in the standard Wilson formulation of lattice field theory.\nIn fact, there is a no-go theorem that prevents the construction of an\nefficient Wolff-type embedding algorithm. In this paper, we construct an\nefficient cluster algorithm for ferromagnetic SU(N)-symmetric quantum spin\nsystems. Such systems provide a regularization for CP(N-1) models in the\nframework of D-theory. We present detailed studies of the autocorrelations and\nfind a dynamical critical exponent that is consistent with z = 0.",
        "positive": "Lattice calculation of the lowest order hadronic contribution to the\n  muon anomalous magnetic moment: We present a quenched lattice calculation of the lowest order (alpha^2)\nhadronic contribution to the anomalous magnetic moment of the muon which arises\nfrom the hadronic vacuum polarization. A general method is presented for\ncomputing entirely in Euclidean space, obviating the need for the usual\ndispersive treatment which relies on experimental data for e^+e^- annihilation\nto hadrons. While the result is not yet of comparable accuracy to those\nstate-of-the-art calculations, systematic improvement of the quenched lattice\ncomputation to this level of accuracy is straightforward and well within the\nreach of present computers. Including the effects of dynamical quarks is\nconceptually trivial, the computer resources required are not."
    },
    {
        "anchor": "Three ways of calculating mass spectra for the 2-flavor Schwinger model\n  in the Hamiltonian formalism: We propose three independent methods to compute the hadron mass spectra of\ngauge theories in the Hamiltonian formalism. The determination of hadron masses\nis one of the key issues in QCD, which has been precisely calculated by the\nMonte Carlo method in the Lagrangian formalism. We confirm that the mass of\nhadrons can be calculated by examining correlation functions, the one-point\nfunction, or the dispersion relation in Hamiltonian formalism. These methods\nare suitable for quantum computation and tensor network approaches. The methods\nare demonstrated with the tensor network (DMRG) in the 2-flavor Schwinger\nmodel, which shares important properties with QCD. We show that the numerical\nresults are consistent with each other and with the analytic prediction of the\nbosonization technique. We also discuss their efficiency and potential\napplications to other models.",
        "positive": "Evaporation/Condensation of Ising Droplets: Recently Biskup et al. [Europhys. Lett. 60 (2002) 21] studied the behaviour\nof d-dimensional finite-volume liquid-vapour systems at a fixed excess $\\delta\nN$ of particles above the ambient gas density. They identify a dimensionless\nparameter $\\Delta (\\delta N)$ and a universal constant $\\Delta_\\mathrm{c}(d)$\nand show that for $\\Delta < \\Delta_c$ a droplet of the dense phase occurs while\nfor $\\Delta > \\Delta_c$ the excess is absorbed in the background. The fraction\n$\\lambda_\\Delta$ of excess particles forming the droplet is given explicitly.\nFurthermore, they state, that the same is true for solid-gas systems.\n  To verify these results, we have simulated the spin-1/2 Ising model on a\nsquare lattice at constant magnetisation equivalent to a fixed particle excess\nin the lattice-gas picture. We measured the largest minority droplet,\ncorresponding to the solid phase, at various system sizes ($L=40, ..., 640$).\nUsing analytic values for the spontaneous magnetisation $m_0$, the\nsusceptibility $\\chi$ and interfacial free energy $\\tau_\\mathrm{W}$ for the\ninfinite system, we were able to determine $\\lambda_\\Delta$ in very good\nagreement with the theoretical prediction."
    },
    {
        "anchor": "Finite size analysis of the pseudo specific heat in SU(2) gauge theory: We investigate the pseudo specific heat of SU(2) gauge theory near the\ncrossover point on $4^4$ to $16^4$ lattices. Several different methods are used\nto determine the specific heat. The curious finite size dependence of the peak\nmaximum is explained from the interplay of the crossover phenomenon with the\ndeconfinement transition occurring due to the finite extension of the lattice.\nIn this context we calculate the modulus of the lattice average of the Polyakov\nloop on symmetric lattices and compare it to the prediction from a random walk\nmodel.",
        "positive": "Heavy quark diffusion coefficient with gradient flow: We calculate chromo-electric and chromo-magnetic correlators in quenched QCD\nat $1.5T_c$ and $10^4 T_c$ with the aim to estimate the heavy quark diffusion\ncoefficient at leading order in the inverse heavy quark mass expansion,\n$\\kappa_E$, as well as the coefficient of first mass suppressed correction,\n$\\kappa_B$. We use gradient flow for noise reduction. At $1.5T_c$ we obtain:\n$1.70 \\le \\kappa_E/T^3 \\le 3.12$ and $1.03< \\kappa_B/T^3 < 2.61$. The latter\nimplies that the mass suppressed effects in the heavy quark diffusion\ncoefficient are 20% for bottom quarks and 34% for charm quark at this\ntemperature."
    },
    {
        "anchor": "Non-locality of the nucleon-nucleon potential from Lattice QCD: The Nambu-Bethe-Salpeter (NBS) wave function for two nucleons on the lattice\nhas been shown to yield a non-local and energy-independent nucleon-nucleon (NN)\npotential, U(r,r'). In practice, the derivative expansion of U(r,r') is\ncurrently employed to determine the potential at low energies. In this report,\nwe study the magnitude of non-locality to check the convergence of such a\nderivative expansion. With quenched lattice QCD at m_\\pi = 530MeV, we compare\nthe NN potentials at the center of mass energy E ~ 0 MeV and at E ~ 45 MeV. We\nalso investigate the angular momentum dependence of the spin singlet potential,\nby comparing the potentials in 1S0 and 1D2 channels. We find that the\nnon-locality and the angular momentum dependence in the above energy range are\nnegligible within statistical errors.",
        "positive": "Inhomogeneous phases in the Gross-Neveu model in 1+1 dimensions at\n  finite number of flavors: We explore the thermodynamics of the 1+1-dimensional Gross-Neveu (GN) model\nat finite number of fermion flavors $N_f$, finite temperature and finite\nchemical potential using lattice field theory. In the limit $N_f \\rightarrow\n\\infty$ the model has been solved analytically in the continuum. In this limit\nthree phases exist: a massive phase, in which a homogeneous chiral condensate\nbreaks chiral symmetry spontaneously, a massless symmetric phase with vanishing\ncondensate and most interestingly an inhomogeneous phase with a condensate,\nwhich oscillates in the spatial direction. In the present work we use chiral\nlattice fermions (naive fermions and SLAC fermions) to simulate the GN model\nwith 2, 8 and 16 flavors. The results obtained with both discretizations are in\nagreement. Similarly as for $N_f \\rightarrow \\infty$ we find three distinct\nregimes in the phase diagram, characterized by a qualitatively different\nbehavior of the two-point function of the condensate field. For $N_f = 8$ we\nmap out the phase diagram in detail and obtain an inhomogeneous region smaller\nas in the limit $N_f \\rightarrow \\infty$, where quantum fluctuations are\nsuppressed. We also comment on the existence or absence of Goldstone bosons\nrelated to the breaking of translation invariance in 1+1 dimensions."
    },
    {
        "anchor": "Hadron Spectrum for Quenched Domain-Wall Fermions with DBW2 Gauge Action: We investigate basic physical quantities for quenched simulation with\ndomain-wall fermions and the DBW2 gauge action. Masses and decay constant of\npseudoscalar mesons are measured. Scaling properties are tested.",
        "positive": "Renormalization of transverse-momentum-dependent parton distribution on\n  the lattice: To calculate the transverse-momentum-dependent parton distribution functions\n(TMDPDFs) from lattice QCD, an important goal yet to be realized, it is crucial\nto establish a viable non-perturbative renormalization approach for linear\ndivergences in the corresponding Euclidean quasi-TMDPDF correlators in\nlarge-momentum effective theory. We perform a first systematic study of the\nrenormalization property of the quasi-TMDPDFs by calculating the relevant\nmatrix elements in a pion state at 5 lattice spacings ranging from 0.03 fm to\n0.12 fm. We demonstrate that the square root of the Wilson loop combined with\nthe short distance hadron matrix element provides a successful method to remove\nall ultraviolet divergences of the quasi-TMD operator, and thus provide the\nnecessary justification to perform a continuum limit calculation of TMDPDFs. In\ncontrast, the popular RI/MOM renormalization scheme fails to eliminate all\nlinear divergences."
    },
    {
        "anchor": "Gradient flow equation in SQCD: We propose a supersymmetric gradient flow in ${\\cal N}=1$ SQCD in four\ndimensions. The flow equation is derived in the superfield formalism and is\nalso given for component fields of the Wess-Zumino gauge in a gauge covariant\nmanner. We find that the flow for the component fields is supersymmetric in a\nsense that the flow time derivative and any supersymmetry transformation\ncommute with each other up to a gauge transformation.",
        "positive": "Random Geometries and Real Space Renormalization Group: A method of ``blocking'' triangulations that rests on the self-similarity\nfeature of dynamically triangulated random manifolds is proposed. The method is\nused to define the renormalization group for random geometries. As an\nillustration, the idea is applied to pure euclidean quantum gravity in two\ndimensions. Generalisation to more complicated systems and to higher\ndimensionalities of space-time appears straightforward."
    },
    {
        "anchor": "A Parallel SSOR Preconditioner for Lattice QCD: We present a parallelizable SSOR preconditioning scheme for Krylov subspace\niterative solvers which proves to be efficient in lattice QCD applications\ninvolving Wilson fermions. Our preconditioner is based on a locally\nlexicographic ordering of the lattice points. In actual hybrid Monte Carlo\napplications with the bi-conjugate gradient stabilized method BiCGstab, we\nachieve a gain factor of about 2 in the number of iterations compared to\nconventional odd-even preconditioning. Whether this translates into similar\nreductions in run time will depend on the parallel computer in use. We discuss\nimplementation issues using the `Eisenstat-trick' and machine specific\nadvantages of the method for the APE100/Quadrics parallel computer. In a full\nQCD simulation with Wilson fermions on a 512-processor Quadrics QH4 we find a\ngain in cpu-time of a factor of 1.7 over odd-even preconditioning for a 24^3 x\n40 lattice.",
        "positive": "Quantum electrodynamics in finite volume and nonrelativistic effective\n  field theories: Electromagnetic effects are increasingly being accounted for in lattice\nquantum chromodynamics computations. Because of their long-range nature, they\nlead to large finite-size effects over which it is important to gain analytical\ncontrol. Nonrelativistic effective field theories provide an efficient tool to\ndescribe these effects. Here we argue that some care has to be taken when\napplying these methods to quantum electrodynamics in a finite volume."
    },
    {
        "anchor": "The light Roberge-Weiss tricritical endpoint at imaginary isospin and\n  baryon chemical potential: Imaginary chemical potentials serve as a useful tool to constrain the QCD\nphase diagram and to gain insight into the thermodynamics of strongly\ninteracting matter. In this study, we report on the first determination of the\nphase diagram for arbitrary imaginary baryon and isospin chemical potentials at\nhigh temperature using one-loop perturbation theory, revealing a nontrivial\nstructure of Roberge-Weiss (RW) phase transitions in this plane. Subsequently,\nthis system is simulated numerically with $N_{\\rm f}=2$ unimproved staggered\nquarks on $N_{\\tau}=4$ lattices at a range of temperatures at one of the RW\nphase transitions. We establish a lower bound for the light quark mass, where\nthe first-order transition line terminates in a tricritical point. It is found\nthat this tricritical mass is increased as compared to the case of purely\nbaryonic imaginary chemical potentials, indicating that our setup is more\nadvantageous for identifying critical behavior towards the chiral limit.\nFinally, the dynamics of local Polyakov loop clusters is also studied in\nconjuction with the RW phase transition.",
        "positive": "Nambu monopoles in lattice Electroweak theory: We considered the lattice electroweak theory at realistic values of $\\alpha$\nand $\\theta_W$ and for large values of the Higgs mass. We investigated\nnumerically the properties of topological objects that are identified with\nquantum Nambu monopoles. We have found that the action density near the Nambu\nmonopole worldlines exceeds the density averaged over the lattice in the\nphysical region of the phase diagram. Moreover, their percolation probability\nis found to be an order parameter for the transition between the symmetric and\nthe broken phases. Therefore, these monopoles indeed appear as real physical\nobjects. However, we have found that their density on the lattice increases\nwith increasing ultraviolet cutoff. Thus we conclude, that the conventional\nlattice electroweak theory is not able to predict the density of Nambu\nmonopoles. This means that the description of Nambu monopole physics based on\nthe lattice Weinberg - Salam model with finite ultraviolet cutoff is\nincomplete. We expect that the correct description may be obtained only within\nthe lattice theory that involves the description of TeV - scale physics."
    },
    {
        "anchor": "Spatial structure of the color field in the SU(3) flux tube: We report on the chromoelectric and chromomagnetic fields generated by a\nstatic quark-antiquark pair at zero temperature in pure gauge SU(3). From the\nspatial structure of chromoelectric field we extract its nonperturbative part\nand discuss its properties.",
        "positive": "TEK twisted gradient flow running coupling: We measure the running of the twisted gradient flow coupling in the Twisted\nEguchi-Kawai (TEK) model, the SU(N) gauge theory on a single site lattice with\ntwisted boundary conditions in the large N limit."
    },
    {
        "anchor": "QCD, Symmetry Breaking and the Random Lattice: According to the Nielsen-Ninomiya No-Go theorem, the doubling of fermions on\nthe lattice cannot be suppressed in a chiral theory. Whereas Wilson and\nstaggered fermions suppress doublers with explicit breaking of chiral symmetry,\nthe random lattice does so by spontaneous chiral symmetry breaking even in the\nfree theory. I present results for meson masses, the chiral condensate and\nfermionic eigenvalues from simulations of quenched QCD on random lattices in\nfour dimensions, focusing on chiral symmetry breaking.",
        "positive": "Nonperturbative Collins-Soper Kernel from Chiral Quarks with Physical\n  Masses: We present a lattice QCD calculation of the rapidity anomalous dimension of\nquark transverse-momentum-dependent distributions, i.e., the Collins-Soper (CS)\nkernel, up to transverse separations of about 1 fm. This unitary lattice\ncalculation is conducted, for the first time, employing the\nchiral-symmetry-preserving domain wall fermion discretization and physical\nvalues of light and strange quark masses. The CS kernel is extracted from the\nratios of pion quasi-transverse-momentum-dependent wave functions\n(quasi-TMDWFs) at next-to-leading logarithmic perturbative accuracy. Also for\nthe first time, we utilize the recently proposed Coulomb-gauge-fixed\nquasi-TMDWF correlator without a Wilson line. We observe significantly slower\nsignal decay with increasing quark separations compared to the established\ngauge-invariant method with a staple-shaped Wilson line. This enables us to\ndetermine the CS kernel at large nonperturbative transverse separations and\nfind its near-linear dependence on the latter. Our result is consistent with\nthe recent lattice calculation using gauge-invariant quasi-TMDWFs, and agrees\nwith various recent phenomenological parametrizations of experimental data."
    },
    {
        "anchor": "Complex Langevin and boundary terms: As is well known the Complex Langevin (CL) method sometimes fails to converge\nor converges to the wrong limit. We identified one reason for this long ago:\ninsufficient decay of the probability density either near infinity or near\npoles of the drift, leading to boundary terms that spoil the formal argument\nfor correctness. To gain a deeper understanding of this phenomenon, we analyze\nthe emergence of such boundary terms thoroughly in a simple model, where\nanalytic results can be compared with numerics.\n  We also show how some simple modification stabilizes the CL process in such a\nway that it can produce results agreeing with direct integration. Besides\nexplicitly demonstrating the connection between boundary terms and correct\nconvergence our analysis also suggests a correctness criterion which could be\napplied in realistic lattice simulations.",
        "positive": "General solution of cyclic Leibniz rule: We study the general solution of the cyclic Leibniz rule (CLR) which was\nrecently proposed as a new approach to the lattice supersymmetry. Introducing\nsome mathematical preliminaries related to the cyclic symmetry, we find the\ngeneral solution of the 2-body CLR for the naive symmetric difference operator.\nThe main theorems of this paper state that the general solution can be uniquely\nexpressed as (A) a linear combination of the two fundamental solutions with\ncyclic invariant coefficients, and (B) a linear combination of the minimal\nsolutions with complex coefficients. Moreover, an extension to the general\ndifference operators is also discussed."
    },
    {
        "anchor": "Color Structure of Gluon Field Magnetic Mass: The color structure of the gluon field magnetic mass is investigated in the\nlattice SU(2) gluodynamics. To realize that, the interaction between a\nmonopole-antimonopole string and external neutral Abelian chromomagnetic field\nflux is considered. The string is introduced in the way proposed by Srednicki\nand Susskind. The neutral Abelian field flux is introduced through the twisted\nboundary conditions. Monte Carlo simulations are performed on 4D lattices at\nfinite temperature. It is shown that the presence of the Abelian field flux\nweakens the screening of the string field. That means decreasing the gluon\nmagnetic mass for this environment. The contribution of the neutral Abelian\nfield has the form of \"enhancing\" factor in the fitting functions. This\nbehavior independently confirms the long-range nature of the neutral Abelian\nfield reported already in the literature. The comparison with analytic\ncalculations is given.",
        "positive": "Three-particle bound states in a finite volume: unequal masses and\n  higher partial waves: An explicit expression for the finite-volume energy shift of shallow\nthree-body bound states for non-identical particles is obtained in the unitary\nlimit. The inclusion of the higher partial waves is considered. To this end,\nthe method of arXiv:1412.4969 (Mei{\\ss}ner et al.) is generalized for the case\nof unequal masses and arbitrary angular momenta. It is shown that in the S-wave\nand in the equal mass limit, the result from arXiv:1412.4969 is reproduced."
    },
    {
        "anchor": "Technicolor and Lattice Gauge Theory: Technicolor and other theories of dynamical electroweak symmetry breaking\ninvoke chiral symmetry breaking triggered by strong gauge-dynamics, analogous\nto that found in QCD, to explain the observed W, Z, and fermion masses. In this\ntalk we describe why a realistic theory of dynamical electroweak symmetry\nbreaking must, relative to QCD, produce an enhanced fermion condensate. We\nquantify the degree to which the technicolor condensate must be enhanced in\norder to yield the observed quark masses, and still be consistent with\nphenomenological constraints on flavor-changing neutral-currents. Lattice\nstudies of technicolor and related theories provide the only way to demonstrate\nthat such enhancements are possible and, hopefully, to discover viable\ncandidate models. We comment briefly on the current status of non-perturbative\ninvestigations of dynamical electroweak symmetry breaking, and provide a\n\"wish-list\" of phenomenologically-relevant properties that are important to\ncalculate in these theories",
        "positive": "The nature of the Roberge-Weiss Transition in $N_f=2$ QCD with Wilson\n  Fermions on $N_\u03c4=6$ lattices: The finite temperature chiral and deconfinement phase transitions at zero\ndensity for light and heavy quarks, respectively, have analytic continuations\nto imaginary chemical potential. At some critical imaginary chemical potential,\nthey meet the Roberge-Weiss transition between adjacent $Z(3)$ sectors. For\nlight and heavy quarks, where the chiral and deconfinement transitions are\nfirst order, the transition lines meet in a triple point. For intermediate\nmasses chiral or deconfinement transitions are crossover and the Roberge-Weiss\ntransition ends in a second order point. At the boundary between these regimes\nthe junction is a tricritical point, as shown in studies with $N_f=2,3$ flavors\nof staggered and Wilson quarks on $N_\\tau=4$ lattices. Employing finite size\nscaling we investigate the nature of this point as a function of quark mass for\n$N_f=2$ flavors of Wilson fermions with a temporal lattice extent of\n$N_\\tau=6$. In particular we are interested in the change of the location of\ntricritical points compared to our ealier study on $N_\\tau=4$."
    },
    {
        "anchor": "Exact Extended Supersymmetry on a Lattice: Twisted N=4 Super Yang-Mills\n  in Three Dimensions: We propose a lattice formulation of three dimensional super Yang-Mills model\nwith a twisted N=4 supersymmetry. The extended supersymmetry algebra of all the\neight supercharges is fully and exactly realized on the lattice with a modified\n\"Leibniz rule\". The formulation we employ here is a three dimensional extension\nof manifestly gauge covariant method which was developed in our previous\nproposal of Dirac-Kaehler twisted N=2 super Yang-Mills on two dimensional\nlattice. The twisted N=4 supersymmetry algebra is geometrically realized on a\nthree dimensional lattice with link supercharges and the use of \"shifted\"\n(anti-)commutators. A possible solution to the recent critiques on the link\nformulation will be discussed.",
        "positive": "Spectral properties of quarks above T_c in quenched lattice QCD: We analyze the quark spectral function above the critical temperature for\ndeconfinement in quenched lattice QCD using clover improved Wilson fermions in\nLandau gauge. We show that the temporal quark correlator is well reproduced by\na two-pole approximation for the spectral function and analyze the bare quark\nmass dependence of both poles as well as their residues. In the chiral limit we\nfind that the quark spectral function has two collective modes which correspond\nto the normal and plasmino excitations. At large values of the bare quark mass\nthe spectral function is dominated by a single pole."
    },
    {
        "anchor": "Consistency checks for two-body finite-volume matrix elements: I.\n  Conserved currents and bound states: Recently, a framework has been developed to study form factors of two-hadron\nstates probed by an external current. The method is based on relating\nfinite-volume matrix elements, computed using numerical lattice QCD, to the\ncorresponding infinite-volume observables. As the formalism is complicated, it\nis important to provide non-trivial checks on the final results and also to\nexplore limiting cases in which more straightforward predications may be\nextracted. In this work we provide examples on both fronts. First, we show\nthat, in the case of a conserved vector current, the formalism ensures that the\nfinite-volume matrix element of the conserved charge is volume-independent and\nequal to the total charge of the two-particle state. Second, we study the\nimplications for a two-particle bound state. We demonstrate that the\ninfinite-volume limit reproduces the expected matrix element and derive the\nleading finite-volume corrections to this result for a scalar current. Finally,\nwe provide numerical estimates for the expected size of volume effects in\nfuture lattice QCD calculations of the deuteron's scalar charge. We find that\nthese effects completely dominate the infinite-volume result for realistic\nlattice volumes and that applying the present formalism, to analytically remove\nan infinite-series of leading volume corrections, is crucial to reliably\nextract the infinite-volume charge of the state.",
        "positive": "Reconsidering gauge-Higgs continuity: The 3-d Z(2) lattice gauge-Higgs theory is cast in a partial axial gauge\nleaving a residual Z(2) symmetry, global in two directions and local in one. It\nis shown both analytically and numerically that this symmetry breaks\nspontaneously in the Higgs phase and is unbroken in the confinement phase.\nTherefore they must be separated everywhere by a phase transition, in\ncontradiction to a theorem by Fradkin and Shenker. It relied on a fully fixed\nunitary gauge, which prohibits this phase transition explicitly. Thus the\nunfixed gauge theory is not, in this case, equivalent to the unitary-gauge\nversion."
    },
    {
        "anchor": "Light hadrons from Nf=2+1+1 dynamical twisted mass fermions: We present results of lattice QCD simulations with mass-degenerate up and\ndown and mass-split strange and charm (Nf=2+1+1) dynamical quarks using Wilson\ntwisted mass fermions at maximal twist. The tuning of the strange and charm\nquark masses is performed at three values of the lattice spacing a~0.06 fm,\na~0.08 fm and a~0.09 fm with lattice sizes ranging from L~1.9 fm to L~3.9 fm.\nWe perform a preliminary study of SU(2) chiral perturbation theory by combining\nour lattice data from these three values of the lattice spacing.",
        "positive": "Noether supercurrent operator mixing from lattice perturbation theory: In this work we present perturbative results for the renormalization of the\nsupercurrent operator, $S_\\mu$, in ${\\cal N} =1$ Supersymmetric Yang-Mills\ntheory. At the quantum level, this operator mixes with both gauge invariant and\nnoninvariant operators, which have the same global transformation properties.\nIn total, there are 13 linearly independent mixing operators of the same and\nlower dimensionality. We determine, via lattice perturbation theory, the first\ntwo rows of the mixing matrix, which refer to the renormalization of $S_\\mu$,\nand of the gauge invariant mixing operator, $T_\\mu$. To extract these mixing\ncoefficients in the ${\\overline{\\rm MS}}$ renormalization scheme and at\none-loop order, we compute the relevant two-point and three-point Green's\nfunctions of $S_\\mu$ and $T_\\mu$ in two regularizations: dimensional and\nlattice. On the lattice, we employ the plaquette gluonic action and for the\ngluinos we use the fermionic Wilson action with clover improvement."
    },
    {
        "anchor": "The static quark self-energy at O($\u03b1^{20}$) in perturbation theory: In Refs. [1,2] we determined the infinite volume coefficients of the\nperturbative expansions of the self-energies of static sources in the\nfundamental and adjoint representations in SU(3) gluodynamics to order\n$\\alpha^{20}$. We used numerical stochastic perturbation theory [3], where we\nemployed a new second order integrator and twisted boundary conditions. The\nexpansions were obtained in lattice regularization with the Wilson action and\ntwo different discretizations of the covariant time derivative within the\nPolyakov loop. Overall, we obtained four different perturbative series. For all\nof them the high order coefficients displayed the factorial growth predicted by\nthe conjectured renormalon picture, based on the operator product expansion.\nThis enabled us to determine the normalization constants of the leading\ninfrared renormalons of heavy quark and heavy gluino pole masses. Here we\npresent improved determinations of the normalization constants and the\nperturbative coefficients by incorporating the four-loop beta-function\ncoefficient (which we also determine) in the fit function.",
        "positive": "Hot Electroweak Matter Near to the Critical Higgs Mass: We discuss the end of the first order phase transition and the bound state\nspectrum, both at weak transition and at the crossover."
    },
    {
        "anchor": "A Lattice Calculation of the Heavy Quark Universal Form Factor: A computation of the Isgur-Wise universal form factor using a lattice\nimplementation of the heavy quark effective theory is described, and the\nresults of a lattice simulation are presented.",
        "positive": "Renormalization group coupling flow of SU(3) gauge theory: We present our new results on the renormalization group coupling flow\nobtained i n 3 dimensional coupling space\n$(\\beta_{11},\\beta_{12},\\beta_{twist})$. The value of $\\beta_{twist}$ turns out\nto be small and the coupling flow projected on $(\\beta_{11},\\beta_{12})$ plane\nis very similar with the previous result obtained in the 2 dimensional coupling\nspace."
    },
    {
        "anchor": "Large-$N$ expansion and $\u03b8$-dependence of $2d$ $CP^{N-1}$ models\n  beyond the leading order: We investigate the $\\theta$-dependence of 2-dimensional $CP^{N-1}$ models in\nthe large-$N$ limit by lattice simulations. Thanks to a recent algorithm\nproposed by M. Hasenbusch to improve the critical slowing down of topological\nmodes, combined with simulations at imaginary values of $\\theta$, we manage to\ndetermine the vacuum energy density up the sixth order in $\\theta$ and up to $N\n= 51$. Our results support analytic predictions, which are known up to the\nnext-to-leading term in $1/N$ for the quadratic term in $\\theta$ (topological\nsusceptibility), and up to the leading term for the quartic coefficient $b_2$.\nMoreover, we give a numerical estimate of further terms in the $1/N$ expansion\nfor both quantities, pointing out that the $1/N$ convergence for the\n$\\theta$-dependence of this class of models is particularly slow.",
        "positive": "Towards 4-loop NSPT result for a 3-dimensional condensate-contribution\n  to hot QCD pressure: Thanks to dimensional reduction, the contributions to the hot QCD pressure\ncoming from so-called soft modes can be studied via an effective\nthree-dimensional theory named Electrostatic QCD (spatial Yang-Mills fields\nplus an adjoint Higgs scalar). The poor convergence of the perturbative series\nwithin EQCD suggests to perform lattice measurements of some of the associated\ngluon condensates. These turn out, however, to be plagued by large\ndiscretization artifacts. We discuss how Numerical Stochastic Perturbation\nTheory can be exploited to determine the full lattice spacing dependence of one\nof these condensates up to 4-loop order, and sharpen our tools on a concrete\n2-loop example."
    },
    {
        "anchor": "Non-compact QED3 at finite temperature: the confinement-deconfinement\n  transition: The confinement-deconfinement phase transition is explored by lattice\nnumerical simulations in non-compact (2+1)-dimensional quantum electrodynamics\nwith massive fermions at finite temperature. The existence of two phases, one\nwith and the other without confinement of fractional charges, is related to the\nrealization of the Z symmetry. The order parameter of this transition can be\nclearly identified. We show that it is possible to detect the critical\ntemperature for a given value of the fermion mass, by exploiting suitable\nlattice operators as probes of the Z symmetry. Moreover, the large-distance\nbehavior of the correlation of these operators permits to distinguish the phase\nwith Coulomb-confinement from the Debye-screened phase. The resulting scenario\nis compatible with the existence of a Berezinsky-Kosterlitz-Thouless\ntransition. Some investigations are presented on the possible relation between\nchiral and deconfinement transitions and on the role of ``monopoles''.",
        "positive": "B and D Meson Decay Constants: We present an update of our calculations of the decay constants of the D,\nD_s, B, and B_s mesons in unquenched 2+1 flavor QCD. We use the MILC library of\nimproved staggered gauge ensembles at lattice spacings 0.09, 0.12, and 0.15 fm,\nclover heavy quarks with the Fermilab normalizations, and improved staggered\nlight valence quarks."
    },
    {
        "anchor": "Searching for the first radial excitation of the $\u0394(1232)$ in\n  lattice QCD: We present a lattice QCD analysis of the $ \\Delta $-baryon spectrum, with the\ngoal of finding the position of the $ 2s $ radial excitation of the $\n\\Delta(1232) $ ground state. Using smeared three-quark operators in a\ncorrelation matrix analysis, we report masses for the ground, first and second\nexcited states of the $ J^P = 3/2^+ $ spectrum across a broad range of $\nm_\\pi^2 $. We identify the lowest lying state as being a $ 1s $ state,\nconsistent with the well known $ \\Delta(1232) $. The first excitation is\nidentified as a $ 2s $ state, but is found to have a mass of approximately\n2.15~GeV on our $ \\sim3 $ fm lattice, which does not appear to be associated\nwith the $ \\Delta(1600) $ resonance in a significant manner. We also report on\nthe spin-$ 1/2 $ and odd-parity states accessible via our methods. The large\nexcitation energies of the radial excitations provide a potential resolution to\nthe long-standing missing baryon resonances problem.",
        "positive": "Finite-volume effects in long-distance processes with massless leptonic\n  propagators: In Ref. [1], a method was proposed to calculate QED corrections to hadronic\nself energies from lattice QCD without power-law finite-volume errors. In this\npaper, we extend the method to processes which occur at second-order in the\nweak interaction and in which there is a massless (or almost massless) leptonic\npropagator. We demonstrate that, in spite of the presence of the propagator of\nan almost massless electron, such an infinite-volume reconstruction procedure\ncan be used to obtain the amplitude for the rare kaon decay\n$K^+\\to\\pi^+\\nu\\bar\\nu$ from a lattice quantum chromodynamics computation with\nonly exponentially small finite-volume corrections."
    },
    {
        "anchor": "Bound-state/elementary-particle duality in the Higgs sector and the case\n  for an excited 'Higgs' within the standard model: Though being weakly interacting, QED can support bound states. In principle,\nthis can be expected for the weak interactions in the Higgs sector as well. In\nfact, it has been argued long ago that there should be a duality between bound\nstates and the elementary particles in this sector, at least in leading order\nin an expansion in the Higgs condensate. Whether this remains true beyond the\nleading order is investigated using lattice simulations, and support is found.\nThis provides a natural interpretation of peaks in cross sections as bound\nstates. Unambiguously, this would imply the existence of (possibly very broad)\nresonances of Higgs and W and Z bound states within the standard model.",
        "positive": "The XY model at finite chemical potential using complex Langevin\n  dynamics: The three-dimensional XY model is studied at finite chemical potential using\ncomplex Langevin dynamics. An adaptive stepsize algorithm is implemented to\ncure the problem of runaway solutions that appears when using a constant\nstepsize. The validity of complex Langevin dynamics is tested against\ncalculations using imaginary chemical potential and the world line formalism.\nWhile complex Langevin dynamics is found to work correctly at larger beta, it\nfails for smaller beta, in the region of the phase diagram corresponding to the\ndisordered phase. Diagnostic tests are developed to identify behaviour\nsymptomatic of incorrect convergence. These indicate that the failure does not\ndepend on the severeness of the sign problem, but has a different origin."
    },
    {
        "anchor": "Supersymmetric Nonlinear O(3) Sigma Model on the Lattice: A supersymmetric extension of the nonlinear O(3) sigma model in two spacetime\ndimensions is investigated by means of Monte Carlo simulations. We argue that\nit is impossible to construct a lattice action that implements both the O(3)\nsymmetry as well as at least one supersymmetry exactly at finite lattice\nspacing. It is shown by explicit calculations that previously proposed\ndiscretizations fail to reproduce the exact symmetries of the target manifold\nin the continuum limit. We provide an alternative lattice action with exact\nO(3) symmetry and compare two approaches based on different derivative\noperators. Using the nonlocal SLAC derivative for the quenched model on\nmoderately sized lattices we extract the value {\\sigma}(2, u_0) = 1.2604(13)\nfor the step scaling function at u_0 = 1.0595, to be compared with the exact\nvalue 1.261210. For the supersymmetric model with SLAC derivative the discrete\nchiral symmetry is maintained but we encounter strong sign fluctuations,\nrendering large lattice simulations ineffective. By applying the Wilson\nprescription, supersymmetry and chiral symmetry are broken explicitly at finite\nlattice spacing, though there is clear evidence that both are restored in the\ncontinuum limit by fine tuning of a single mass parameter.",
        "positive": "Automatic O(a) improvement for twisted-mass QCD in the presence of\n  spontaneous symmetry breaking: In this paper we present a proof for automatic O(a) improvement in twisted\nmass lattice QCD at maximal twist, which uses only the symmetries of the\nleading part in the Symanzik effective action. In the process of the proof we\nclarify that the twist angle is dynamically determined by vacuum expectation\nvalues in the Symanzik theory. For maximal twist according to this definition,\nwe show that scaling violations of all quantities which have non-zero values in\nthe continuum limit are even in a. In addition, using Wilson Chiral\nPerturbation Theory (WChPT), we investigate this definition for maximal twist\nand compare it to other definitions which were already employed in actual\nsimulations."
    },
    {
        "anchor": "Non-compact lattice Higgs model with Abelian discrete gauge groups:\n  phase diagram and gauge symmetry enlargement: We study the phase diagram and phase transitions of the three dimensional\nmulticomponent lattice Higgs model with non-compact Abelian discrete groups.\nThe model with non-compact U(1) gauge group is known to undergo, for a\nsufficiently large number of scalar fields $N$, a continuous transition\nassociated to the charged fixed point of the continuous Abelian Higgs field\ntheory. We show that in the model with gauge group $\\mathbb{Z}_q^{(nc)}\\equiv\n2\\pi\\mathbb{Z}/q$ only critical transitions in the orthogonal universality\nclasses are present for small values of $N$, while a symmetry enlargement to\nthe continuous Abelian Higgs universality class happens when $q\\ge 5$ and $N$\nis large enough.",
        "positive": "The Effective String of 3D Z_2 Gauge Theory as a c=1 compactified CFT: We report on a high precision Montecarlo test of the three dimensional Ising\ngauge model at finite temperature. The string tension $\\sigma$ is extracted\nfrom the expectation values of correlations of Polyakov lines. Agreement with\nthe string tension extracted from Wilson loops is found only if the quantum\nfluctuations of the flux tube are properly taken into account. The central\ncharge of the underlying conformal field theory is c=1."
    },
    {
        "anchor": "Optimizing the Chiral Properties of Lattice Fermions: We describe a way to optimize the chiral behavior of Wilson-type lattice\nfermion actions by studying the low energy real eigenmodes of the Dirac\noperator. We find a candidate action, the clover action with fat links with a\ntuned clover term. The action shows good scaling behavior at Wilson gauge\ncoupling beta=5.7.",
        "positive": "The Casimir effect and deconfinement phase transition: We show that the Casimir effect may lead to a deconfinement phase transition\ninduced by the presence of boundaries in confining gauge theories. Using\nfirst-principle numerical simulations we demonstrate this phenomenon in the\nsimplest case of the compact lattice electrodynamics in two spatial dimensions.\nWe find that the critical temperature of the deconfinement transition in the\nvacuum between two parallel dielectric/metallic wires is a monotonically\nincreasing function of the separation between the wires. At infinite separation\nthe wires do not affect the critical temperature while at small separations the\nvacuum between the wires looses the confinement property due to modification of\nvacuum fluctuations of virtual monopoles."
    },
    {
        "anchor": "Effective Potential and Phase Diagram in the Strong-Coupling Lattice QCD\n  with Next-to-Next-to-Leading Order and Polyakov Loop Effects: We investigate chiral and deconfinement transitions in the strong coupling\nlattice QCD for color SU(3). We combine the leading order Polyakov loop\neffective action of the strong coupling expansion and the\nnext-to-next-to-leading order (1/g^4) fermionic effective action with one\nspecies of unrooted staggered fermion. Two approximation schemes are adopted to\nevaluate the Polyakov loop effects; a Haar measure method (no fluctuation from\nthe mean field) and a Weiss mean-field method (with fluctuations). The Polyakov\nloop is found to suppress the chiral condensate and to reduce the chiral\ntransition temperature at mu = 0. The chiral transition temperature roughly\nreproduces the Monte Carlo results in the region beta = 2N_c /g^2 < 4.",
        "positive": "Lifshitz-type SU(N) lattice gauge theory in five dimensions: We present a lattice formulation of non-Abelian Lifshitz-type gauge theories.\nDue to anisotropic scaling of space and time, the theory is asymptotically free\neven in five dimensions. We show results of Monte Carlo simulations that\nsuggest a smooth approach to the continuum limit."
    },
    {
        "anchor": "Topological charge density renormalization in the presence of dynamical\n  fermions: We study the renormalization group behaviour of the topological charge\ndensity in full QCD on the lattice. We propose a way of extracting the\nnecessary renormalization functions from Monte Carlo simulations.",
        "positive": "Low-energy couplings of QCD from topological zero-mode wave functions: By matching 1/m^2 divergences in finite-volume two-point correlation\nfunctions of the scalar or pseudoscalar densities with those obtained in chiral\nperturbation theory, we derive a relation between the Dirac operator zero-mode\neigenfunctions at fixed non-trivial topology and the low-energy constants of\nQCD. We investigate the feasibility of using this relation to extract the pion\ndecay constant, by computing the zero-mode correlation functions on the lattice\nin the quenched approximation and comparing them with the corresponding\nexpressions in quenched chiral perturbation theory."
    },
    {
        "anchor": "Deconfinement transition in two-flavour lattice QCD with dynamical\n  overlap fermions: We study the deconfinement transition in two-flavour lattice QCD with\ndynamical overlap fermions. Our simulations have been carried out on a $16^3\n\\times 6$ lattice at a pion mass around 500 MeV with a special HMC algorithm\nwithout any approximation such as fixed topology. We consider several\ntemperatures from 220 MeV which is close to the deconfinement to 280 MeV which\nis above it. The dependence of the Polyakov loop, the chiral condensate, the\nDirac spectra and the connected part of chiral susceptibility on the inverse\ngauge coupling has been studied. Our data indicates that the transition point\nlies between $\\beta = 7.6$ and $\\beta = 8.1$, but a more precise determination\nis not possible with our present statistics.",
        "positive": "Creutz Fermions on an Orthogonal Lattice: In a recent paper, Creutz has given a new action describing two species of\nDirac fermions with exact chiral symmetry on the lattice. This action depends\non a parameter which may be fixed at a certain value in order to get the right\ncontinuum limit. In this letter, we elaborate more on this idea and present an\naction which is free of any other parameter except the fermion mass."
    },
    {
        "anchor": "Reducing the beta-shift in domain wall fermion simulations: The beta-shift induced from dynamical domain wall quarks leads to increased\nroughness of the gauge field, thus reversing the effect of smoothing from the\ngauge action improvement. By exploiting the relation of overlap and domain wall\nfermions in greater detail,we propose an algorithm which reduces the beta-shift\nto the level of dynamical overlap fermions.",
        "positive": "SU(N) gauge theories in four dimensions: exploring the approach to N =\n  infinity: We calculate the string tension, K, and some of the lightest glueball masses,\nM, in 3+1 dimensional SU(N) lattice gauge theories for N=2,3,4,5 . From the\ncontinuum extrapolation of the lattice values, we find that the mass ratios,\nM/sqrt(K), appear to show a rapid approach to the large-N limit, and, indeed,\ncan be described all the way down to SU(2) using just a leading O(1/NxN)\ncorrection. We confirm that the smooth large-N limit we find, is obtained by\nkeeping a constant 't Hooft coupling. We also calculate the topological charge\nof the gauge fields. We observe that, as expected, the density of small-size\ninstantons vanishes rapidly as N increases, while the topological\nsusceptibility appears to have a non-zero N=infinity limit."
    },
    {
        "anchor": "An Experimenter's View of Lattice QCD: Lattice QCD has the potential this decade to maximize the sensitivity of the\nentire flavor physics program to new physics and pave the way for understanding\nphysics beyond the Standard Model at the LHC in the coming decade. However, the\nchallenge for the Lattice is to demonstrate reliability at the level of a few\nper cent given a past history of 10-20% errors. The CLEO-c program at the\nCornell Electron Storage Ring is providing the data that will make the\ndemonstration possible.",
        "positive": "Decoupling a Fermion Whose Mass Comes from a Yukawa Coupling:\n  Nonperturbative Considerations: Perturbative analyses seem to suggest that fermions whose mass comes solely\nfrom a Yukawa coupling to a scalar field can be made arbitrarily heavy, while\nthe scalar remains light. The effects of the fermion can be summarized by a\nlocal effective Lagrangian for the light degrees of freedom. Using weak\ncoupling and large N techniques, we present a variety of models in which this\nconclusion is shown to be false when nonperturbative variations of the scalar\nfield are considered. The heavy fermions contribute nonlocal terms to the\neffective action for light degrees of freedom. This resolves paradoxes about\nanomalous and nonanomalous symmetry violation in these models. Application of\nthese results to lattice gauge theory imply that attempts to decouple lattice\nfermion doubles by the method of Swift and Smit cannot succeed, a result\nalready suggested by lattice calculations."
    },
    {
        "anchor": "Finite temperature phase transition of two-flavor QCD with an improved\n  Wilson quark action: We study the phase structure of QCD at finite temperatures with two flavors\nof dynamical quarks on a lattice with the size $N_s^3 \\times N_t=16^3 \\times\n4$, using a renormalization group improved gauge action and a clover improved\nWilson quark action. The simulations are made along the lines of constant\nphysics determined in terms of $m_{\\rm PS}/m_{\\rm V}$ at zero-temperature. We\nshow preliminary results for the spatial string tension in the high temperature\nphase.",
        "positive": "Kaon $B$-parameters for Generic $\u0394S=2$ Four-Quark Operators in\n  Quenched Domain Wall QCD: We present a study of $B$-parameters for generic $\\Delta S=2$ four-quark\noperators in domain wall QCD. Our calculation covers all the $B$-parameters\nrequired to study the neutral kaon mixing in the standard model (SM) and beyond\nit. We evaluate one-loop renormalization factors of the operators employing the\nplaquette and Iwasaki gauge actions. Numerical simulations are carried out in\nquenched QCD with both gauge actions on $16^3\\times 32\\times 16$ and\n$24^3\\times 32\\times 16$ at the lattice spacing $1/a\\approx 2$GeV. We\ninvestigate the relative magnitudes of the non-SM $B$-parameters to the SM one,\nwhich are compared with the previous results obtained with the overlap and the\nclover quark actions."
    },
    {
        "anchor": "Does the QCD plasma contain propagating gluons?: Comparison of two appropriately chosen screening masses of colour singlet\noperators in the pure glue QCD plasma indicates that at sufficiently high\ntemperature it contains a weakly-interacting massive quasi-particle with the\nquantum numbers of the electric gluon. Still in the deconfined phase, but\ncloser to T_c, the same mass ratio is similar to that at zero temperature,\nindicating that the propagating modes are more glueball-like, albeit with a\nlower scale for the masses. We observe a continuity between these two regimes.",
        "positive": "A Study of the Nambu--Jona-Lasinio Model on the Lattice: We present our full analysis of the two flavor Nambu--Jona-Lasinio model with\n$SU(2) \\times SU(2)$ chiral symmetry on the four--dimensional hypercubic\nlattice with naive and Wilson fermions. We find that this model is an excellent\ntoy field theory to investigate issues related to lattice QCD. We use the large\n$N$ approximation to leading order in $1/N$ to obtain non perturbative\nanalytical results over almost the whole parameter range. By using numerical\nsimulations we estimate that the size of the $1/N$ corrections for most of the\nquantities we consider are small and in this way we strengthen the validity of\nthe leading order large $N$ calculations. We obtain results regarding the\napproach to the continuum chiral limit, the effects of the zero momentum\nfermionic modes on finite lattices and the scalar and pseudoscalar spectrum.\nNote: The full ps file of this preprint is also available via anonymous ftp to\nftp.scri.fsu.edu. To get the ps file, ftp to this address and use for username\n\"anonymous\" and for password your complete E-mail address. The file is in the\ndirectory pub/vranas (to go to that directory type: cd pub/vranas) and is\ncalled NJL_long.ps (to get it type: get NJL_long.ps)"
    },
    {
        "anchor": "The gluonic excitation of the three-quark system in SU(3) lattice QCD: We present the first study of the gluonic excitation in the three-quark (3Q)\nsystem in SU(3) lattice QCD with $\\beta$=5.8 and $16^3 \\times 32 $ at the\nquenched level. For the spatially-fixed 3Q system, we measure the gluonic\nexcited-state potential, which corresponds to the flux-tube vibrational energy\nin the flux-tube picture. The lowest gluonic-excitation energy in the 3Q system\nis found to be about 1GeV in the hadronic scale. This large gluonic-excitation\nenergy is expected to bring about the success of the simple quark model without\ngluonic modes.",
        "positive": "Quark mass effects on the topological susceptibility in QCD: We investigate topology in lattice simulations of QCD with two flavours of\ndynamical Wilson fermions. At various sea quark masses we find reasonable\nagreement between results for the topological charge from fermionic and gluonic\ndefinitions, the latter with cooling. We study correlations of the topological\ncharge with light hadronic observables and find effects in the flavour singlet\npseudoscalar channel. The quark mass dependence of the topological\nsusceptibility, $\\chi$, is in agreement with the leading order small m_pi\nexpectation, chi=(f_pi m_pi)^2/4."
    },
    {
        "anchor": "With complex Langevin towards the QCD phase diagram: We use complex Langevin simulations to explore the QCD phase diagram over a\nlarge range of chemical potentials and temperatures. For our simulations, we\nuse two flavours of dynamical Wilson fermions with a pion mass of approximately\n$480\\,$MeV with a spatial volume of $24^3$. Here we report on consistency\nchecks at zero chemical potentials and present our results for the fermion\ndensity and the Polyakov loop. We find that at the lowest temperature the\nfermion density remains zero until $m_N/3$, in line with the expectations from\nthe Silver Blaze phenomenon.",
        "positive": "Quenched Chiral Behavior of Hadrons with Overlap Fermions: We study the quenched chiral behavior of hadrons with the pseudoscalar mass\nas low as $\\approx 280$ MeV. We look for quenched chiral logs in the pion mass,\ndetermine the renormalized quark mass, and observe quenched artifacts in the\n$a_0$ and $N^*$ propagators. The calculation is done on a quenched lattice of\nsize $20^4$ and $a = 0.148(2)$ fm using overlap fermions and an improved gauge\naction."
    },
    {
        "anchor": "Effective field theories for rooted staggered fermions: We extend the construction of the Symanzik effective action to include rooted\nstaggered fermions, starting from a generalization of the renormalization-group\napproach to rooted staggered fermions. The Symanzik action, together with the\nusual construction of a partially quenched chiral effective theory from a\nlocal, partially quenched, fundamental theory, can then be used to derive the\nchiral effective theory. The latter reproduces rooted staggered chiral\nperturbation theory.",
        "positive": "Three dimensional finite temperature SU(3) gauge theory in the confined\n  region and the string picture: We determine the correlation between Polyakov loops in three dimensional\nSU(3) gauge theory in the confined region at finite temperature. For this\npurpose we perform lattice calculations for the number of steps in the\ntemperature direction equal to six. This is expected to be in the scaling\nregion of the lattice theory. We compare the results to the bosonic string\nmodel. The agreement is very good for temperatures T<0.7T_c, where T_c is the\ncritical temperature. In the region 0.7T_c<T<T_c we enter the critical region,\nwhere the critical properties of the correlations are fixed by universality to\nbe those of the two dimensional three state Potts model. Nevertheless, by\ncalculating the critical lattice coupling, we show that the ratio of the\ncritical temperature to the square root of the zero temperature string tension,\nwhere the latter is taken from the literature, remains very near to the string\nmodel prediction."
    },
    {
        "anchor": "Isoscalar meson spectroscopy from lattice QCD: We extract to high statistical precision an excited spectrum of\nsingle-particle isoscalar mesons using lattice QCD, including states of high\nspin and, for the first time, light exotic JPC isoscalars. The use of a novel\nquark field construction has enabled us to overcome the long-standing challenge\nof efficiently including quark-annihilation contributions. Hidden-flavor mixing\nangles are extracted and while most states are found to be close to ideally\nflavor mixed, there are examples of large mixing in the pseudoscalar and axial\nsectors in line with experiment. The exotic JPC isoscalar states appear at a\nmass scale comparable to the exotic isovector states.",
        "positive": "Locality and topology with fat link overlap actions: We study the locality and topological properties of fat link clover overlap\n(FCO) actions. We find that a small amount of fattening (2-4 steps of APE or 1\nstep of HYP) already results in greatly improved properties compared to the\nWilson overlap (WO). We present a detailed study of the localisation of the FCO\nand its connection to the density of low modes of $A^\\dagger A$. In contrast to\nthe Wilson overlap, on quenched gauge backgrounds we do not find any dependence\nof the localization of the FCO on the gauge coupling. This suggests that the\nFCO remains local in the continuum limit. The FCO also faithfully reproduces\nthe zero mode wave functions of typical lattice instantons, not like the Wilson\noverlap. After a general discussion of different lattice definitions of the\ntopological charge we also show that the FCO together with the Boulder charge\nare likely to satisfy the index theorem in the continuum limit. Finally, we\npresent a high statistics computation of the quenched topological\nsusceptibility with the FCO action."
    },
    {
        "anchor": "Spontaneous breaking of discrete symmetries in QCD on a small volume: In a compact space with non-trivial cycles, for sufficiently small values of\nthe compact dimensions, charge conjugation (C), spatial reflection (P) and time\nreversal (T) are spontaneously broken in QCD. The order parameter for the\nsymmetry breaking is the trace of the Wilson line wrapping around the compact\ndimension, which acquires an imaginary part in the broken phase. We show that a\nphysical signature for the symmetry breaking is a persistent baryonic current\nwrapping in the compact directions. The existence of such a current is derived\nanalytically at first order in perturbation theory and confirmed in the\nnon-perturbative regime by lattice simulations.",
        "positive": "An estimate of the flavour singlet contributions to the hyperfine\n  splitting in charmonium: We explore the splitting between flavour singlet and non-singlet mesons in\ncharmonium. This has implications for the hyperfine splitting in charmonium."
    },
    {
        "anchor": "The QCD phase diagram at nonzero quark density: We determine the phase diagram of QCD on the \\mu-T plane for small to\nmoderate chemical potentials. Two transition lines are defined with two\nquantities, the chiral condensate and the strange quark number susceptibility.\nThe calculations are carried out on N_t =6,8 and 10 lattices generated with a\nSymanzik improved gauge and stout-link improved 2+1 flavor staggered fermion\naction using physical quark masses. After carrying out the continuum\nextrapolation we find that both quantities result in a similar curvature of the\ntransition line. Furthermore, our results indicate that in leading order the\nwidth of the transition region remains essentially the same as the chemical\npotential is increased.",
        "positive": "On the extraction of spectral quantities with open boundary conditions: We discuss methods to extract decay constants, meson masses and gluonic\nobservables in the presence of open boundary conditions. The ensembles have\nbeen generated by the CLS effort and have 2+1 flavors of O(a)-improved Wilson\nfermions with a small twisted-mass term as proposed by L\\\"uscher and Palombi.\nWe analyse the effect of the associated reweighting factors on the computation\nof different observables."
    },
    {
        "anchor": "Toward a proof of long range order in 4-d SU(N) lattice gauge theory: An extended version of 4-d SU(2) lattice gauge theory is considered in which\ndifferent inverse coupling parameters are used, $\\beta_H=4/g_{H}^2$ for\nplaquettes which are purely spacelike, and $\\beta_V$ for those which involve\nthe Euclidean timelike direction. It is shown that when $\\beta_H = \\infty$ the\npartition function becomes, in the Coulomb Gauge, exactly that of a set of\nnon-interacting 3-d O(4) classical Heisenberg models. Long range order at low\ntemperatures (weak coupling) has been rigorously proven for this model. It is\nshown that the correlation function demonstrating spontaneous magnetization in\nthe ferromagnetic phase is a continuous function of $g_H$ at $g_H =0$ and\ntherefore that the spontaneously broken phase enters the ($\\beta_H$, $\\beta_V$)\nphase plane (no step discontinuity at the edge). Once the phase transition line\nhas entered, it can only exit at another identified edge, which requires the\nSU(2) gauge theory within also to have a phase transition at finite $\\beta$. A\nphase exhibiting spontaneous breaking of the remnant symmetry left after\nCoulomb gauge fixing, the relevant symmetry here, is non-confining. Easy\nextension to the SU(N) case implies that the continuum limit of\nzero-temperature 4-d SU(N) lattice gauge theories is not confining, in other\nwords gluons by themselves do not produce a confinement.",
        "positive": "The Chiral Condensate in a Finite Volume: Chiral perturbation theory at finite four-volume V (=L^3T) is reconsidered\nwith a view towards finding a computational scheme that can deal with any value\nof M_\\pi L, where M_\\pi is a generic Nambu-Goldstone mass. The momentum zero\nmodes that cause the usual p-expansion to fail in the chiral limit are treated\nseparately, and partly integrated out to all orders. In this way the theory\nremains infrared finite in the perturbative expansion, and the chiral limit can\nbe considered at finite volume. We illustrate the technique by computing the\nquark condensate in a finite volume, smoothly connecting standard results in\nthe p-regime for larger masses with those of the epsilon-regime for smaller\nmasses. From the partially quenched theory we also obtain the spectral density\nof the Dirac operator, a smooth function from the microscopic region to the\nbulk region of the p-regime."
    },
    {
        "anchor": "Probing the chiral limit with clover fermions II: The baryon sector: Algorithmic progress in recent years made it possible to simulate QCD with\nNf=2 flavours of O(a)-improved Wilson fermions at very light quark masses. We\npresent the current results for baryon spectrum states, the nucleon axial\ncoupling and the lowest moment of unpolarised nucleon structure functions.\nSpecial emphasis is given to a comparison of our calculations with results from\nchiral effective theories.",
        "positive": "Perturbative O($a^2$) effects in gradient flow couplings with SF and\n  SF-open boundary conditions: The gradient flow provides a new class of renormalized observables which can\nbe measured with high precision in lattice simulations. In principle this\nallows for many interesting applications to renormalization and improvement\nproblems. In practice, however, such applications are made difficult by the\nrather large cutoff effects found in many gradient flow observables. At lowest\norder of perturbation theory we here study the leading cutoff effects in a\nfinite volume gradient flow coupling with SF and SF-open boundary conditions.\nWe confirm that O($a^2$) Symanzik improvement is achieved at tree-level,\nprovided the action, observable and the flow are O($a^2$) improved. O($a^2$)\neffects from the time boundaries are found to be absent at this order, both\nwith SF and SF-open boundary conditions. For the calculation we have used a\nconvenient representation of the free gauge field propagator at finite flow\ntimes which follows from a recently proposed set-up by L\\\"uscher and renders\nlattice perturbation theory more practical at finite flow time and with SF,\nopen, SF-open or open-SF boundary conditions."
    },
    {
        "anchor": "Large-$q$ expansion of the specific heat for the two-dimensional\n  $q$-state Potts model: We have calculated the large-$q$ expansion for the specific heat at the phase\ntransition point in the two-dimensional $q$-state Potts model to the 23rd order\nin $1/\\sqrt{q}$ using the finite lattice method. The obtained series allows us\nto give highly convergent estimates of the specific heat for $q>4$ on the first\norder transition point. The result confirm us the correctness of the conjecture\nby Bhattacharya et al. on the asymptotic behavior of the specific heat for $q\n\\to 4_+$.",
        "positive": "Light quark electromagnetic structure of baryons: Fascinating aspects of the light quark-mass behavior of baryon\nelectromagnetic form factors are highlighted. Using FLIC fermions on $20^3\n\\times 40$ quenched ${\\cal O}(a^2)$-improved gauge fields, we explore charge\nradii and magnetic moments at pion masses as light as 300 MeV. Of particular\ninterest is chiral curvature of proton charge radii and magnetic moments, the\nenvironmental dependence of strange quark properties in hyperons, and the\nremarkable signature of quenched chiral-nonanalytic behavior in the magnetic\nmoment of $\\Delta$ baryon resonances."
    },
    {
        "anchor": "Flavor symmetry breaking and scaling for improved staggered actions in\n  quenched QCD: We present a study of the flavor symmetry breaking in the pion spectrum for\nvarious improved staggered fermion actions. To study the effects of link\nfattening and tadpole improvement, we use three different variants of the p4\naction - p4fat3, p4fat7, and p4fat7tad. These are compared to Asqtad and also\nto naive staggered. To study the pattern of symmetry breaking, we measure all\n15 meson masses in the 4-flavor staggered theory. The measurements are done on\na quenched gauge background, generated using a one-loop improved Symanzik\naction with $\\beta=10/g^2 = 7.40, 7.75,$ and 8.00, corresponding to lattice\nspacings of approximately a = .31 fm., .21 fm., and .14 fm. We also study how\nthe lattice scale set by the $\\rho$ mass on each of these ensembles compares to\none set by the static quark potential.",
        "positive": "Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: isospin-2\n  $\u03c0\u03c0$ scattering length: We present results for the $I=2$ $\\pi\\pi$ scattering length using $N_f=2+1+1$\ntwisted mass lattice QCD for three values of the lattice spacing and a range of\npion mass values. Due to the use of Laplacian Heaviside smearing our\nstatistical errors are reduced compared to previous lattice studies. A detailed\ninvestigation of systematic effects such as discretisation effects, volume\neffects, and pollution of excited and thermal states is performed. After\nextrapolation to the physical point using chiral perturbation theory at NLO we\nobtain $M_\\pi a_0=-0.0442(2)_\\mathrm{stat}(^{+4}_{-0})_\\mathrm{sys}$."
    },
    {
        "anchor": "Analytic calculation of the mass gap in U(1)_{2+1} lattice gauge theory: An analytic calculation of the photon mass gap M of compact U(1)_{2+1} in the\nHamiltonian formalism is performed utilizing the first four Hamiltonian moments\nwith respect to a one-plaquette mean field state in the plaquette expansion\nmethod. Scaling of M is clearly evident at and beyond the transition from\nstrong to weak coupling. The scaling behaviour agrees well with the range of\nresults from numerical calculations.",
        "positive": "Effective lattice Polyakov loop theory vs. full SU(3) Yang-Mills at\n  finite temperature: A three-dimensional effective theory of Polyakov loops has recently been\nderived from Wilson's Yang-Mills lattice action by means of a strong coupling\nexpansion. It is valid in the confined phase up to the deconfinement phase\ntransition, for which it predicts the correct order and gives quantitative\nestimates for the critical coupling. In this work we study its predictive power\nfor further observables like correlation functions and the equation of state.\nWe find that the effective theory correctly reproduces qualitative features and\nsymmetries of the full theory as the continuum is approached. Regarding\nquantitative predictions, we identify two classes of observables by numerical\ncomparison as well as analytic calculations: correlation functions and their\nassociated mass scales cannot be described accurately from a truncated\neffective theory, due to its inherently non-local nature involving long-range\ncouplings. On the other hand, phase transitions and bulk thermodynamic\nquantities are accurately reproduced by the leading local part of the effective\ntheory. In particular, the effective theory description is numerically superior\nwhen computing the equation of state at low temperatures or the properties of\nthe phase transition."
    },
    {
        "anchor": "Magnetic polarisability of the nucleon using a Laplacian mode projection: Conventional hadron interpolating fields, which utilise gauge-covariant\nGaussian smearing, are ineffective in isolating ground state nucleons in a\nuniform background magnetic field. There is evidence that residual Landau mode\nphysics remains at the quark level, even when QCD interactions are present. In\nthis work, quark-level projection operators are constructed from the $SU(3)\n\\times U(1)$ eigenmodes of the two-dimensional lattice Laplacian operator\nassociated with Landau modes. These quark-level modes are formed from a\nperiodic finite lattice where both the background field and strong interactions\nare present. Using these eigenmodes, quark-propagator projection operators\nprovides the enhanced hadronic energy-eigenstate isolation necessary for\ncalculation of nucleon energy shifts in a magnetic field. The magnetic\npolarisability of both the proton and neutron is calculated using this method\non the $32^3 \\times 64$ dynamical QCD lattices provided by the PACS-CS\nCollaboration. A chiral effective-field theory analysis is used to connect the\nlattice QCD results to the physical regime, obtaining magnetic polarisabilities\nof $\\beta^p = 2.79(22)({}^{+13}_{-18}) \\times 10^{-4}$ fm$^3$ and $\\beta^n =\n2.06(26)({}^{+15}_{-20}) \\times 10^{-4}$ fm$^3$, where the numbers in\nparantheses describe statistical and systematic uncertainties.",
        "positive": "Multicanonical Study of Continuum Physics in the D=2 $O(3)$ Nonlinear\n  Sigma Model: Employing a variant of the Multicanonical Ensemble we study twisted spin\nconfigurations on periodic boxes in the $D=2$ $O(3)$ nonlinear sigma model for\n$\\beta$-values inbetween $1.55$ to $3.1$. The free energy difference of twisted\nspin configurations is determined from the constraint effective potential. The\nfinite size scaling behavior is in accordance with the asymptotically free\nnature of the continuum theory. Upon certain reasonable assumptions we\ndetermine the $\\Delta \\beta( \\beta)$-shift of the stiffness correlation length\n$\\xi_s$. The mass-gap as determined by our analysis is\n${m_0}=79.6(1.9)~\\Lambda_{latt}$. This value agrees with the analytical result\nof the thermodynamic Bethe Ansatz ${m_0}=80.1~\\Lambda_{latt}$."
    },
    {
        "anchor": "Charmed and strange pseudoscalar meson decay constants from HISQ\n  simulations: We update our determinations of $f_{D^+}$, $f_{D_s}$, $f_K$, and quark mass\nratios from simulations with four flavors of HISQ dynamical quarks. The\navailability of ensembles with light quarks near their physical mass means that\nwe can extract physical results with only small corrections for valence- and\nsea-quark mass mistunings instead of a chiral extrapolation. The adjusted\nvalence-quark masses and lattice spacings may be determined from an\nensemble-by-ensemble analysis, and the results for the quark mass ratios then\nextrapolated to the continuum limit. Our central values of the charmed meson\ndecay constants, however, come from an alternative analysis, which uses\nstaggered chiral perturbation theory for the heavy-light mesons, and allows us\nto incorporate data at unphysical quark masses where statistical errors are\noften smaller. A jackknife analysis propagated through all of these steps takes\naccount of the correlations among all the quantities used in the analysis.\nSystematic errors from the finite spatial size and EM effects are estimated by\nvarying the parameters in the analysis, and systematic errors from the\nassumptions in the continuum extrapolation are estimated from the spread of\nvalues from different extrapolations.",
        "positive": "Rotor Spectra and Berry Phases in the Chiral Limit of QCD on a Torus: We consider the finite-volume spectra of QCD in the chiral limit of massless\nup and down quarks and massive strange quarks in the baryon number sectors $B =\n0$ and $B = 1$ for different values of the isospin. Spontaneous symmetry\nbreaking gives rise to rotor spectra, as the chiral order parameter precesses\nthrough the vacuum manifold. Baryons of different isospin influence the motion\nof the order parameter through non-trivial Berry phases and associated abstract\nmonopole fields. Our investigation provides detailed insights into the dynamics\nof spontaneous chiral symmetry breaking in QCD on a torus. It also sheds new\nlight on Berry phases in the context of quantum field theory. Interestingly,\nthe Berry gauge field resulting from QCD solves a Yang-Mills-Chern-Simons\nequation of motion on the vacuum manifold $SU(2) = S^3$."
    },
    {
        "anchor": "Towards corrections to the strong coupling limit of staggered lattice\n  QCD: We report on the first steps of an ongoing project to add gauge observables\nand gauge corrections to the well-studied strong coupling limit of staggered\nlattice QCD, which has been shown earlier to be amenable to numerical\nsimulations by the worm algorithm in the chiral limit and at finite density.\nHere we show how to evaluate the expectation value of the Polyakov loop in the\nframework of the strong coupling limit at finite temperature, allowing to study\nconfinement properties along with those of chiral symmetry breaking. We find\nthe Polyakov loop to rise smoothly, thus signalling deconfinement. The\nnon-analytic nature of the chiral phase transition is reflected in the\nderivative of the Polyakov loop. We also discuss how to construct an effective\ntheory for non-zero lattice coupling, which is valid to $O(\\beta)$.",
        "positive": "Sign problem in finite density lattice QCD: The canonical approach, which was developed for solving the sign problem, may\nsuffer from a new type of sign problem. In the canonical approach, the grand\npartition function is written as a fugacity expansion: $Z_G(\\mu,T) = \\sum_n\nZ_C(n,T) \\xi^n$, where $\\xi=\\exp(\\mu/T)$ is the fugacity, and $Z_C(n,T)$ are\ngiven as averages over a Monte Carlo update, $\\langle z_n\\rangle$. We show that\nthe complex phase of $z_n$ is proportional to $n$ at each Monte Carlo step.\nAlthough $\\langle z_n\\rangle$ take real positive values, the values of $z_n$\nfluctuate rapidly when $n$ is large, especially in the confinement phase, which\ngives a limit on $n$. We discuss possible remedies for this problem."
    },
    {
        "anchor": "Acceptance Rates in Multigrid Monte Carlo: An approximation formula is derived for acceptance rates of nonlocal\nMetropolis updates in simulations of lattice field theories. The predictions of\nthe formula agree quite well with Monte Carlo simulations of 2-dimensional Sine\nGordon, XY and phi**4 models. The results are consistent with the following\nrule: For a critical model with a fundamental Hamiltonian H(phi) sufficiently\nhigh acceptance rates for a complete elimination of critical slowing down can\nonly be expected if the expansion of < H(phi+psi) > in terms of the shift psi\ncontains no relevant term (mass term).",
        "positive": "Partially quenched chiral perturbation theory in the epsilon regime at\n  next-to-leading order: We calculate the partition function of partially quenched chiral perturbation\ntheory in the epsilon regime at next-to-leading order using the supersymmetry\nmethod in the formulation without a singlet particle. We include a nonzero\nimaginary chemical potential and show that the finite-volume corrections to the\nlow-energy constants $\\Sigma$ and $F$ for the partially quenched partition\nfunction, and hence for spectral correlation functions of the Dirac operator,\nare the same as for the unquenched partition function. We briefly comment on\nhow to minimize these corrections in lattice simulations of QCD. As a side\nresult, we show that the zero-momentum integral in the formulation without a\nsinglet particle agrees with previous results from random matrix theory."
    },
    {
        "anchor": "Static quark-antiquark potential in the quark-gluon plasma from lattice\n  QCD: We present a state-of-the-art determination of the complex valued static\nquark-antiquark potential at phenomenologically relevant temperatures around\nthe deconfinement phase transition. Its values are obtained from\nnon-perturbative lattice QCD simulations using spectral functions extracted via\na novel Bayesian inference prescription. We find that the real part, both in a\ngluonic medium as well as in realistic QCD with light $u$, $d$ and $s$ quarks,\nlies close to the color singlet free energies in Coulomb gauge and shows Debye\nscreening above the (pseudo) critical temperature $T_c$. The imaginary part is\nestimated in the gluonic medium, where we find that it is of the same order of\nmagnitude as in hard-thermal loop resummed perturbation theory in the\ndeconfined phase.",
        "positive": "A note on Zolotarev optimal rational approximation for the overlap Dirac\n  operator: We discuss the salient features of Zolotarev optimal rational approximation\nfor the inverse square root function, in particular, for its applications in\nlattice QCD with overlap Dirac quark. The theoretical error bound for the\nmatrix-vector multiplication $ H_w (H_w^2)^{-1/2}Y $ is derived. We check that\nthe error bound is always satisfied amply, for any QCD gauge configurations we\nhave tested. An empirical formula for the error bound is determined, together\nwith its numerical values (by evaluating elliptic functions) listed in Table 2\nas well as plotted in Figure 3. Our results suggest that with Zolotarev\napproximation to $ (H_w^2)^{-1/2} $, one can practically preserve the exact\nchiral symmetry of the overlap Dirac operator to very high precision, for any\ngauge configurations on a finite lattice."
    },
    {
        "anchor": "Precision Control in Lattice Calculation of $x$-dependent Pion\n  Distribution Amplitude: We present a new Bjorken $x$-dependence analysis of a previous lattice\nquantum chromodynamics data for the pion distribution amplitude from MILC\nconfigurations with three lattice spacing $a=0.06,0.09, 0.12$~fm. A leading\nrenormalon resummation in renormalization as well as the perturbative matching\nkernel in the framework of large momentum expansion generates the power\naccuracy of the matching to the light-cone amplitude. Meanwhile, a small\nmomentum log resummation is implemented for both the quark momentum $xP_z$ and\nthe antiquark momentum $(1-x)P_z$ inside a meson of boost momentum $P_z$ up to\n1.72 GeV along the $z$ direction, allowing us to have more accurate\ndetermination of the $x$-dependence in the middle range. Finally, we use the\ncomplementarity between the short-distance factorization and the large momentum\nexpansion to constrain the endpoint regions $x\\sim 0, 1$, thus obtaining the\nfull-range $x$-dependence of the amplitude.",
        "positive": "Chiral Condensate and Susceptibility of SU(2) $n_f=8$ Naive Staggered\n  System: The SU(2) gauge theory with 8 fundamental fermions is studied using\nunimproved staggered regularization. A phase transition or a crossover at\nstrong coupling, which can be a bulk transition. By using chiral random matrix\nmodel we analyze the chiral condensate of this system. We also report the\nchiral susceptibility and its volume dependence near the transition point."
    },
    {
        "anchor": "To what distances do we know the confining potential?: We argue that asymptotically linear static potential is built in into the\ncommon procedure of extracting it from lattice Wilson loop measurements. To\nillustrate the point, we extract the potential by the standard lattice method\nin a model vacuum made of instantons. A beautiful infinitely rising linear\npotential is obtained in the case where the true potential is actually\nflattening. We argue that the flux tube formation might be also an artifact of\nthe lattice procedure and not necessarily a measured physical effect.\n  We conclude that at present the rising potential is known for sure up to no\nmore than about 0.7 fm. It may explain why no screening has been clearly\nobserved so far for adjoint sources and for fundamental sources but with\ndynamical fermions.\n  Finally, we speculate on how confinement could be achieved even if the static\npotential in the pure glue theory is not infinitely rising.",
        "positive": "A Quasi-staggered Scheme on Lattice: Utilizing a picture of string and string spinors, we show a simpler version\nof staggered action. The advantage of this action is that in this action there\nalways exist pair of quarks with different masses."
    },
    {
        "anchor": "Latent heat and pressure gap at the first-order deconfining phase\n  transition of SU(3) Yang-Mills theory using the small flow-time expansion\n  method: We study latent heat and the pressure gap between the hot and cold phases at\nthe first-order deconfining phase transition temperature of the SU(3)\nYang-Mills theory. Performing simulations on lattices with various spatial\nvolumes and lattice spacings, we calculate the gaps of the energy density and\npressure using the small flow-time expansion (SFtX) method. We find that the\nlatent heat $\\Delta \\epsilon$ in the continuum limit is $\\Delta \\epsilon /T^4 =\n1.117 \\pm 0.040$ for the aspect ratio $N_s/N_t=8$ and $1.349 \\pm 0.038$ for\n$N_s/N_t=6$ at the transition temperature $T=T_c$. We also confirm that the\npressure gap is consistent with zero, as expected from the dynamical balance of\ntwo phases at $T_c$. From hysteresis curves of the energy density near $T_c$,\nwe show that the energy density in the (metastable) deconfined phase is\nsensitive to the spatial volume, while that in the confined phase is\ninsensitive. Furthermore, we examine the effect of alternative procedures in\nthe SFtX method - the order of the continuum and the vanishing flow-time\nextrapolations, and also the renormalization scale and higher-order corrections\nin the matching coefficients. We confirm that the final results are all very\nconsistent with each other for these alternatives.",
        "positive": "Chiral low-energy constants from lattice QCD: Different strategies for the computation of QCD low-energy couplings by\nmatching lattice results with the chiral effective theory are reviewed. After\nrecalling some relevant predictions from the effective theory, the current\nstatus of leading order (\\Sigma,F, Sigma_0,F_0) and next-to-leading order (l_i,\nL_i) low-energy constants is summarized, focusing on recent results obtained\nwith N_f=2 and N_f=2+1 lattice simulations."
    },
    {
        "anchor": "Testing (asymptotic) scaling in Yang-Mills theories in the large-$N_c$\n  limit: TEK reduction is a well-established technique that allows single-site\nsimulations of Yang-Mills theory in the large-$N_c$ limit by exploiting volume\nreduction induced by twisted boundary conditions. We performed simulations for\n$SU(841)$ for several gauge couplings and applied standard Wilson flow\ntechniques combined with a tree-level improvement methodology to set the\nlattice scale. The wide range of gauge couplings covered by our simulations\nallows us to explore a region in the coupling space where our data exhibits\nasymptotic scaling and perturbation theory could be used to analyze the\nbehaviour of the $\\beta$-function. In this talk, I will review the methodology\nused and go through the main results we obtained, including a determination of\nthe $\\Lambda$-parameter of Yang-Mills theory at large-$N_c$ in\n$\\overline{\\text{MS}}$-scheme.",
        "positive": "Perturbative renormalisation of the chiral Gross-Neveu model: We study the chiral Gross-Neveu model with Wilson fermions. In the framework\nof the Schroedinger functional we show that in general not only the bare mass\nhas to be tuned to achieve chiral symmetry in the continuum, but also coupling\nconstants multiplying chirally non-invariant four fermion terms. The strategy\nfor fixing the parameters of the theory is explained in perturbation theory and\nthe results of a first order calculation are presented. The results are shown\nto agree with the infinite flavour limit."
    },
    {
        "anchor": "Cold Atom Quantum Simulator for String and Hadron Dynamics in\n  Non-Abelian Lattice Gauge Theory: We propose an analog quantum simulator for simulating real time dynamics of\n$(1+1)$-d non-Abelian gauge theory well within the existing capacity of\nultracold atom experiments. The scheme calls for the realization of a two-state\nultracold fermionic system in a 1-dimensional bipartite lattice, and the\nobservation of subsequent tunneling dynamics. Being based on novel loop string\nhadron formalism of SU(2) lattice gauge theory, this simulation technique is\ncompletely SU(2) invariant and simulates accurate dynamics of physical\nphenomena such as string breaking and/or pair production. The scheme is\nscalable, and particularly effective in simulating the theory in weak coupling\nregime, and also bulk limit of the theory in strong coupling regime up to\ncertain approximations. This paper also presents a numerical benchmark\ncomparison of exact spectrum and real time dynamics of lattice gauge theory to\nthat of the atomic Hamiltonian with experimentally realizable range of\nparameters.",
        "positive": "I=2 $\u03c0$-$\u03c0$ scattering length with dynamical overlap fermion: We report on a lattice QCD calculation of the I=2 $\\pi\\pi$ scattering length\nusing the overlap fermion formulation for both sea and valence quarks. We\ninvestigate the consistency of the lattice data with the prediction of the\nnext-to-next-to-leading order chiral perturbation theory after correcting\nfinite volume effects. The calculation is performed on gauge ensembles of\ntwo-flavor QCD generated by the JLQCD collaboration on a $16^3\\times 32$\nlattice at a lattice spacing $\\sim$ 0.12 fm."
    },
    {
        "anchor": "Classically Perfect Gauge Actions on Anisotropic Lattices: We present a method for constructing classically perfect anisotropic actions\nfor SU(3) gauge theory based on an isotropic Fixed Point Action. The action is\nparametrised using smeared (``fat'') links. The construction is done explicitly\nfor anisotropy $\\xi=a_s/a_t=2$ and 4. The corresponding renormalised\nanisotropies are determined using the torelon dispersion relation. The\nrenormalisation of the anisotropy is small and the parametrisation describes\nthe true action well. Quantities such as the static quark-antiquark potential,\nthe critical temperature of the deconfining phase transition and the low-lying\nglueball spectrum are measured on lattices with anisotropy $\\xi=2$. The mass of\nthe scalar $0^{++}$ glueball is determined to be 1580(60) MeV, while the tensor\n$2^{++}$ glueball is at 2430(60) MeV.",
        "positive": "Quantum chaos and chiral symmetry at the QCD and QED phase transition: We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)\ngauge theory and in full QCD as well as in quenched U(1) theory. As a measure\nof the fluctuation properties of the eigenvalues, we consider the\nnearest-neighbor spacing distribution. We find that in all regions of their\nphase diagrams, compact lattice gauge theories have bulk spectral correlations\ngiven by random matrix theory, which is an indication for quantum chaos. In the\nconfinement phase, the low-lying Dirac spectrum of these quantum field theories\nis well described by random matrix theory, exhibiting universal behavior.\nRelated results for gauge theories with minimal coupling are now discussed also\nin the chirally symmetric phase."
    },
    {
        "anchor": "The nucleon axial charge in full lattice QCD: The nucleon axial charge is calculated as a function of the pion mass in full\nQCD. Using domain wall valence quarks and improved staggered sea quarks, we\npresent the first calculation with pion masses as light as 354 MeV and volumes\nas large as (3.5 fm)^3. We show that finite volume effects are small for our\nvolumes and that a constrained fit based on finite volume chiral perturbation\ntheory agrees with experiment within 7% statistical errors.",
        "positive": "Strong coupling constant from moments of quarkonium correlators\n  revisited: We revisit previous determination of the strong coupling constant from\nmoments of quarkonium correlators in (2+1)-flavor QCD. We use previously\ncalculated moments obtained with Highly Improved Staggered Quark (HISQ) action\nfor five different quark masses and several lattice spacings. We perform a\ncareful continuum extrapolations of the moments and from the comparison of\nthese to the perturbative result we determine the QCD Lambda parameter,\n$\\Lambda_{\\overline{MS}}^{n_f=3}=332 \\pm 17 \\pm 2(scale)$ MeV. This corresponds\nto $\\alpha_s^{n_f=5}(\\mu=M_Z)=0.1177(12)$."
    },
    {
        "anchor": "Prospects of Solving Grand Challenge Problems: The recent woes of the supercomputer industry and changes in federal funding\nhave caused some scientists to re-evaluate the means by which they hope to\nsolve Grand Challenge problems. I evaluate the potential of Massively Parallel\nProcessors (MPP) within this context and the state of today's MPP. I stress\nthat for solving large-scale problems MPP are crucial and that it is essential\nto seek a balance between CPU performance, memory access time, inter-node\ncommunications, and I/O. To achieve this it is important to preserve certain\ncharacteristics of the hardware while selecting the hottest processor to design\nthe machine around. I emphasize that for long term stability and growth of\nparallel computing priority should be given to standardizing software so that\nthe same code can run on different platforms and on machines ranging from\nclusters of workstations to MPP.",
        "positive": "Bottomonium spectral widths at nonzero temperature using maximum\n  likelihood: We present progress results from the Fastsum collaboration's programme to\ndetermine the spectrum of the bottomonium system as a function of temperature\nusing a variety of approaches. In these proceedings, the Maximum Likelihood\napproach is used with an Ansatz comprising of a Gaussian spectral function for\nthe ground state. Fastsum anisotropic lattices with 2+1 dynamical quark\nflavours were used with temperatures ranging from 47 to 375 MeV."
    },
    {
        "anchor": "Glueballs and the superfluid phase of Two-Color QCD: We present the first results on scalar glueballs in cold, dense matter using\nlattice simulations of two color QCD. The simulations are carried out on a $6^3\n\\times 12$ lattice and use a standard hybrid molecular dynamics algorithm for\nstaggered fermions for two values of quark mass. The glueball correlators are\nevaluated via a multi-step smearing procedure. The amplitude of the glueball\ncorrelator peaks in correspondence with the zero temperature chiral transition,\n$\\mu_c = m_\\pi/2$, and the propagators change in a significant way in the\nsuperfluid phase, while the Polyakov loop is mearly insensitive to the\ntransition. Standard analysis suggest that lowest mass in the $0^{++}$ gluonic\nchannel decreases in the superfluid phase, but these observations need to be\nconfirmed on larger and more elongated lattices These results indicate that a\nnonzero density induces nontrivial modifications of the gluonic medium.",
        "positive": "Lee-Yang and Langer edge singularities from analytic continuation of\n  scaling functions: We discuss the analytic continuation of scaling function in the 3-dimensional\nZ(2),O(2) andO(4) universality classes using the Schofield representation of\nthe magnetic equation of state. We show that a determination of the location of\nLee-Yang edge singularities and, in the case of Z(2), also the Langer edge\nsingularity yields stable results. Results for the former are in good agreement\nwith Functional Renormalization Group calculations. We also present results for\nthe location of the Langer edge singularity in the 3-d,Z(2) universality class.\nWe find that in terms of the complex scaling variable z the distance of the\nLanger edge singularity to the critical point agrees within errors with that of\nthe Lee-Yang edge singularity. Furthermore the magnitude of the discontinuity\nalong the Langer branch cut is an order of magnitude smaller than that along\nthe Lee-Yang branch cut."
    },
    {
        "anchor": "Abelian color cycles: a new approach to strong coupling expansion and\n  dual representations for non-abelian lattice gauge theory: We propose a new approach to strong coupling series and dual representations\nfor non-abelian lattice gauge theories using the SU(2) case as an example. The\nWilson gauge action is written as a sum over \"abelian color cycles\" (ACC) which\ncorrespond to loops in color space around plaquettes. The ACCs are complex\nnumbers which can be commuted freely such that the strong coupling series and\nthe dual representation can be obtained as in the abelian case. Using a\nsuitable representation of the SU(2) gauge variables we integrate out all\noriginal gauge links and identify the constraints for the dual variables in the\nSU(2) case. We show that the construction can be generalized to the case of\nSU(2) gauge fields with staggered fermions. The result is a strong coupling\nseries where all gauge integrals are known in closed form and we discuss its\napplicability for possible dual simulations. The abelian color cycle concept\ncan be generalized to other non-abelian gauge groups such as SU(3).",
        "positive": "Testing universality and automatic O(a) improvement in massless lattice\n  QCD with Wilson quarks: The chirally rotated Schroedinger functional provides a test bed for\nuniversality and automatic O(a) improvement. We here report on extensive\nquenched simulations of lattice QCD with Wilson quarks in the massless limit.\nWe demonstrate that, after proper tuning of a dimension 3 boundary counterterm,\nthe expected chirally rotated boundary conditions are indeed obtained. This\nimplies automatic O(a) improvement which we then verify in a few examples.\nUniversality of properly renormalized correlation functions is confirmed by\ncomparing to the standard set-up of the Schroedinger functional. As a\nby-product of this study the non-singlet current renormalisation constants Z_A\nand Z_V are obtained from ratios of 2-point functions."
    },
    {
        "anchor": "The Approach to the Thermodynamic Limit in Lattice QCD at \u03bc\\neq0: The expectation value of the complex phase factor of the fermion determinant\nis computed to leading order in the $p$-expansion of the chiral Lagrangian. The\ncomputation is valid for $\\mu<m_\\pi/2$ and determines the dependence of the\nsign problem on the volume and on the geometric shape of the volume. In the\nthermodynamic limit with $ L_i \\to \\infty $ at fixed temperature $1/L_0$, the\naverage phase factor vanishes. In the low temperature limit where $L_i/L_0$ is\nfixed as $L_i$ becomes large the average phase factor approaches one. The\nresults for a finite volume compare well with lattice results obtained by\nAllton {\\it et al}.. After taking appropriate limits, we reproduce previously\nderived results for the $\\epsilon$-regime and for 1-dimensional QCD. The\ndistribution of the phase itself is also computed.",
        "positive": "Static Potential and Local Color Fields in Unquenched Three-Dimensional\n  Lattice QCD: String breaking by dynamical quarks in (2+1)-d lattice QCD is demonstrated in\nthis project, by measuring the static potential and the local color-electric\nfield strength between a heavy quark and antiquark pair at large separations.\nSimulations are done for unquenched SU(2) color with two flavors of staggered\nquarks. An improved gluon action is used which allows simulations to be done on\ncoarse lattices, providing an extremely efficient means to access the quark\nseparations and propagation times at which string breaking occurs. The static\nquark potential is extracted using only Wilson loop operators and hence no\nvalence quarks are present in the trial states. Results give unambiguous\nevidence for string breaking as the static quark potential completely saturates\nat twice the heavy-light meson mass at large separations. It is also shown that\nthe local color-electric field strength between the quark pair tends toward\nvacuum values at large separations. Implications of these results for\nunquenched simulations of QCD in 4-d are drawn."
    },
    {
        "anchor": "Scattering of Goldstone Bosons and resonance production in a Composite\n  Higgs model on the lattice: We calculate the coupling between a vector resonance and two Goldstone bosons\nin $SU(2)$ gauge theory with $N_f=2$ Dirac fermions in the fundamental\nrepresentation. The considered theory can be used to construct a minimal\nComposite Higgs models. The coupling is related to the width of the vector\nresonance and we determine it by simulating the scattering of two Goldstone\nbosons where the resonance is produced. The resulting coupling is\n$g_{\\rm{VPP}}=7.8\\pm 0.6$, not far from $g_{\\rho\\pi \\pi}\\simeq 6$ in QCD. This\nis the first lattice calculation of the resonance properties for a minimal UV\ncompletion. This coupling controls the production cross section of the lightest\nexpected resonance at the LHC and enters into other tests of the Standard\nModel, from Vector Boson Fusion to electroweak precision tests. Our prediction\nis crucial to constrain the model using lattice input and for understanding the\nbehavior of the vector meson production cross section as a function of the\nunderlying gauge theory. We also extract the coupling $g_{\\rm{VPP}}^{\\rm{KSRF}}\n=9.4 \\pm 0.6$ assuming the vector-dominance and find that this phenomenological\nestimate slightly overestimates the value of the coupling.",
        "positive": "Towards the quark--gluon plasma Equation of State with dynamical strange\n  and charm quarks: We present an ongoing project aimed at determining the thermodynamic Equation\nof State (EoS) of quark--gluon matter from lattice QCD with two generations of\ndynamical quarks. We employ the Wilson twisted mass implementation for the\nfermionic fields and the improved Iwasaki gauge action. Relying on $T=0$ data\nobtained by the ETM Collaboration the strange and charm quark masses are fixed\nat their physical values, while the pion mass takes four values in the range\nfrom 470 MeV down to 210 MeV. The temperature is varied within a fixed--lattice\nscale approach. The values for the pseudocritical temperature are obtained from\nvarious observables. For the EoS we show preliminary results for the pure\ngluonic contribution obtained at the pion mass value 370 MeV, where we can\ncompare with previously obtained results with $N_f=2$ degenerate light\nflavours."
    },
    {
        "anchor": "The leading disconnected contribution to the anomalous magnetic moment\n  of the muon: The hadronic vacuum polarization can be determined from the vector correlator\nin a mixed time-momentum representation. We explicitly calculate the\ndisconnected contribution to the vector correlator, both in the $N_f = 2$\ntheory and with an additional quenched strange quark, using non-perturbatively\n$O(a)$-improved Wilson fermions. All-to-all propagators are computed using\nstochastic sources and a generalized hopping parameter expansion. Combining the\nresult with the dominant connected contribution, we are able to estimate an\nupper bound for the systematic error that arises from neglecting the\ndisconnected contribution in the determination of $(g-2)_\\mu$.",
        "positive": "Chern-Simons Currents and Chiral Fermions on the Lattice: We compute the Chern-Simons current induced by Wilson fermions on a $d=2n+1$\ndimensional lattice, making use of a topological interpretation of the momentum\nspace fermion propagator as a map from the torus to the sphere, $T^{d}\\to\nS^{d}$. These mappings are shown to fall in different homotopy classes\ndepending on the value of $m/r$, where $m$ is the fermion mass and $r$ is the\nWilson coupling. As a result, the induced Chern-Simons term changes\ndiscontinuously at $d+1$ different values for $m$, unlike in the continuum.\nThis behavior is exactly what is required by the peculiar spectrum found for a\nrecently proposed model of chiral lattice fermions as zeromodes bound to a\ndomain wall."
    },
    {
        "anchor": "Meson correlators in a finite volume near the chiral limit: We report on the results of our calculation of meson correlators in a finite\nvolume. The calculation is carried out in the quenched approximation near the\nchiral limit (down to Mq = 2.6 MeV) using the overlap fermion. For these small\nquark masses, the scalar and pseudo-scalar correlators are well approximated\nwith a few hundred eigenmodes. The results for both connected and disconnected\ncorrelators are compared with the theoretical predictions of quenched chiral\nperturbation theory.",
        "positive": "About a possible 3rd order phase transition at T=0 in 4D gluodynamics: We revisit the question of the convergence of lattice perturbation theory for\na pure SU(3) lattice gauge theory in 4 dimensions. Using a series for the\naverage plaquette up to order 10 in the weak coupling parameter beta^{-1}, we\nshow that the analysis of the extrapolated ratio and the extrapolated slope\nsuggests the possibility of a non-analytical power behavior of the form\n(1/\\beta -1/5.7(1))^{1.0(1)}, in agreement with another analysis based on the\nsame asumption. This would imply that the third derivative of the free energy\ndensity diverges near beta =5.7. We show that the peak in the third derivative\nof the free energy present on 4^4 lattices disappears if the size of the\nlattice is increased isotropically up to a 10^4 lattice. On the other hand, on\n4 x L^3 lattices, a jump in the third derivative persists when L increases. Its\nlocation coincides with the onset of a non-zero average for the Polyakov loop.\nWe show that the apparent contradiction at zero temperature can be resolved by\nmoving the singularity in the complex 1/\\beta plane. If the imaginary part of\nthe location of the singularity Gamma is within the range 0.001< Gamma < 0.01,\nit is possible to limit the second derivative of P within an acceptable range\nwithout affecting drastically the behavior of the perturbative coefficients. We\ndiscuss the possibility of checking the existence of these complex\nsingularities by using the strong coupling expansion or calculating the zeroes\nof the partition function."
    },
    {
        "anchor": "Three-body scattering and quantization conditions from $S$ matrix\n  unitarity: Two methodologies have been presented in the literature which connect\nrelativistic three-particle scattering amplitudes with lattice QCD spectra --\nthe ``relativistic effective field theory'' approach and the ``finite-volume\nunitarity'' method. While both methods have been shown to be equivalent in\nvarious works, it has not been shown how to arrive at the relativistic\neffective field theory results directly from $S$ matrix unitarity. In this\nwork, we provide a simple proof of the relativistic effective field theory form\nof the scattering equations directly from unitarity. Motivated by the\nfinite-volume unitarity approach, we then postulate a set of quantization\nconditions which relate the finite-volume energy spectra to the $K$ matrices\nwhich drive the short-distance physics in the scattering equations, obtaining\nall previously known results for three identical particles. This work also\npresents new relations which provide a new pathway to generalize the results to\narbitrary systems.",
        "positive": "Confinement/deconfinement phase transition in SU(3) Yang-Mills theory\n  and non-Abelian dual Meissner effect: The dual superconductivity is a promising mechanism of quark confinement. In\nthe preceding works, we have given a non-Abelian dual superconductivity picture\nfor quark confinement, and demonstrated the numerical evidences on the lattice.\n  In this talk, we focus on the the confinement and deconfinement phase\ntransition at finite temperature in view of the dual superconductivity. By\nusing our new formulation of lattice Yang-Mills theory and numerical\nsimulations on the lattice, we extract the dominant mode for confinement by\ndecomposing the Yang-Mills field, and we investigate the Polyakov loop average,\nstatic quark potential, chromoelectric flux, and induced monopole current for\nboth Yang-Mills field and decomposed restricted field in both confinement and\ndeconfinement phase at finite temperature. We further discuss the role of the\nchromomagnetic monopole in the confinement/deconfinement phase transition."
    },
    {
        "anchor": "Relativistic Heavy Quarks on the Lattice: Lattice QCD should allow quantitative predictions for the heavy quark physics\nfrom first principles. Up to now, however, most approaches have based on the\nnonrelativistic effective theory, with which the continuum limit can not be\ntaken in principle. In this paper we investigate feasibility of relativistic\napproaches to the heavy quark physics in lattice QCD. We first examine validity\nof the idea that the use of the anisotropic lattice could be advantageous to\ncontrol the $m_Q a$ corrections. Our perturbative calculation, however, reveals\nthat this is not true. We instead propose a new relativistic approach to handle\nheavy quarks on the isotropic lattice. We explain how power corrections of $m_Q\na$ can be avoided and remaining uncertainties are reduced to be of order\n$(a\\Lambda_{QCD})^2$.",
        "positive": "K-pi interaction in finite volume and the K* resonance: We evaluate energy levels of the K-pi system in the K* channel in finite\nvolume using chiral unitary theory. We use these energy levels to obtain K-pi\nphase shifts, and then obtain the K* mass and its decay width. We investigate\ntheir dependence on the pion mass and compare this with Lattice QCD\ncalculations. We also compare our method with the standard Luscher approach,\nand solve the inverse problem to obtain the K-pi phase shifts from these\n\"synthetic\" lattice data."
    },
    {
        "anchor": "Polynomial Hybrid Monte Carlo algorithm for lattice QCD with an odd\n  number of flavors: We present a polynomial hybrid Monte Carlo (PHMC) algorithm for lattice QCD\nwith odd numbers of flavors of O(a)-improved Wilson quark action. The algorithm\nmakes use of the non-Hermitian Chebyshev polynomial to approximate the inverse\nsquare root of the fermion matrix required for an odd number of flavors. The\nsystematic error from the polynomial approximation is removed by a noisy\nMetropolis test for which a new method is developed. Investigating the property\nof our PHMC algorithm in the N_f=2 QCD case, we find that it is as efficient as\nthe conventional HMC algorithm for a moderately large lattice size (16^3 times\n48) with intermediate quark masses (m_{PS}/m_V ~ 0.7-0.8). We test our\nodd-flavor algorithm through extensive simulations of two-flavor QCD treated as\nan N_f = 1+1 system, and comparing the results with those of the established\nalgorithms for N_f=2 QCD. These tests establish that our PHMC algorithm works\non a moderately large lattice size with intermediate quark masses (16^3 times\n48, m_{PS}/m_V ~ 0.7-0.8). Finally we experiment with the (2+1)-flavor QCD\nsimulation on small lattices (4^3 times 8 and 8^3 times 16), and confirm the\nagreement of our results with those obtained with the R algorithm and\nextrapolated to a zero molecular dynamics step size.",
        "positive": "Topology across the finite temperature transition studied by\n  overimproved cooling in gluodynamics and QCD: Gluodynamics and two-flavor QCD at non-zero temperature are studied with the\nso-called overimproved cooling technique under which caloron solutions may\nremain stable. We consider topological configurations either at the first\noccuring stable plateau of topological charge or at the first (anti)selfdual\nplateau and find the corresponding topological susceptibility at various\ntemperatures on both sides of the thermal transition or crossover. In pure\ngluodynamics the topological susceptibility drops sharply at the deconfinement\ntemperature while in full QCD it decreases smoothly at temperatures above the\npseudocritical one. The results are close to those calculated by other methods.\nWe interpret our findings in terms of the (in)stability of calorons with\nnon-trivial holonomy and their dyon constituents against overimproved cooling."
    },
    {
        "anchor": "QCD color interactions between two quarks: We study the QCD color interactions between static two heavy quarks at zero\ntemperature in a quenched SU(3) lattice gauge simulation: in addition to the\nstandard singlet $q\\bar{q}$ potentials, we calculate octet $q\\bar{q}$\npotentials, symmetric and antisymmetric $qq$ potentials. It is shown that the\nantisymmetric $qq$ channel behaves as a linearly rising potential at large\nquark separations. We further find that the $q\\bar{q}$ octet and $qq$ symmetric\nchannels have the complex dependence on the distance; at short distances they\nare repulsive forces, while at large distances, they show linearly rising\nfeature. Ratio of string tensions between $q\\bar{q}$ singlet and $qq$\nantisymmetric potentials is described in terms of the Casimir factor.",
        "positive": "Quark-photon vertex from lattice QCD in Landau gauge: We study the nonperturbative structure of the quark-photon vertex in Landau\ngauge. To this end, we utilize lattice QCD data for the vector current for two\nmass-degenerate quark flavours and extract all longitudinal and transverse form\nfactors of the underlying vertex for two off-shell kinematics. The momentum\ndependence of the form factors is compared to the solution of the inhomogeneous\nBethe-Salpeter equation for the vertex in the rainbow-ladder approximation.\nDifferences but also similarities are seen between our lattice and the\ntruncated continuum results."
    },
    {
        "anchor": "Volume Effects on the Method of Extracting Form Factors at Zero Momentum: The Rome method allows one to extract form factors using lattice computations\nperformed strictly at zero momentum. We investigate the size of finite volume\neffects resulting from this method. As a test case, we focus on the pion charge\nradius and show how to ascertain the finite volume effect with the aid of\nchiral perturbation theory. The framework developed can easily be generalized\nto account for modified infrared physics of other low-energy matrix elements\nextracted at zero momentum.",
        "positive": "Some Pieces of Lattice Evidence in Favor of the Center-Vortex Picture of\n  Color Confinement: We address two questions related to the procedure of identifying center\nvortices based on center projection in maximal center gauge: 1. How does the\nprocedure work, why is it expected to locate center vortices relevant for\nconfinement, and why does it in some cases fail, on lattice configurations\npreconditioned in a special way? 2. Does the mechanism work the same way for 3\ncolors instead of 2? (The paper is an abridged version of two recent e-prints,\nhep-lat/9910033 and hep-lat/9911006.)"
    },
    {
        "anchor": "Status of nucleon structure calculations with 2+1 flavors of domain wall\n  fermions: We report the status of our nucleon structure calculations with 2+1 flavors\nof domain wall fermions on the RBC-UKQCD $32^3\\times64$ gauge ensembles with\nthe Iwasaki+DSDR action. These ensembles have a fixed lattice scale of 1/a =\n1.37 GeV, and two pion masses of about 170 and 250 MeV. Preliminary results for\nthe isovector electromagnectic form factors and their corresponding\nroot-mean-squared (r.m.s.) radii will be presented.",
        "positive": "Thick vortices in SU(2) lattice gauge theory: Three dimensional SU(2) lattice gauge theory is studied after eliminating\nthin monopoles and the smallest thick monopoles. Kinematically this constraint\nallows the formation of thick vortex loops which produce Z(2) fluctuations at\nlonger length scales. The thick vortex loops are identified in a three\ndimensional simulation. A condensate of thick vortices persists even after the\nthin vortices have all disappeared. The thick vortices decouple at a slightly\nlower temperature (higher beta) than the thin vortices and drive a phase\ntransition."
    },
    {
        "anchor": "Pure gauge glueballs at finite temperature: Pure gauge glueballs at finite temperature are investigated in a large\ntemperature range from $0.3T_c$ to $1.9T_c$ on anisotropic lattices. Optimized\nglueball operators are used to obtain better signals. It is found in all 20\nsymmetry channels that the pole masses $M_G$ of glueballs remain almost\nconstants when the temperature approaches the critical temperature $T_c$ from\nbelow, and start to reduce gradually with the temperature going above $T_c$.\nThe glueball correlators in $0^{++}$, $0^{-+}$, and $2^{++}$ channels, are also\nanalyzed based on the Breit-Wigner ansatz by assuming a thermal width $\\Gamma$\nto the pole mass $\\omega_0$. While $\\omega_0$'s are insensitive to $T$ in the\nwhole temperature range, $\\Gamma$'s exhibit distinct behavior below and above\n$T_c$: They are only few percents of $\\omega_0$ when $T<T_c$, but grow abruptly\nwhen $T>T_c$ and reach values of roughly $\\Gamma\\sim \\omega_0/2$ at $T\\approx\n1.9T_c$.",
        "positive": "Hadron properties at finite temperature and density with two-flavor\n  Wilson fermions: Meson properties at finite temperature and density are studied in lattice QCD\nsimulations with two-flavor Wilson fermions. For this purpose, we investigate\nscreening masses of mesons in pseudo-scalar (PS) and vector (V) channels. The\nsimulations are performed on $16^3\\times 4$ lattice along the lines of constant\nphysics at $m_{\\rm PS}/m_{\\rm V}|_{T=0}=0.65$ and 0.80, where $m_{\\rm\nPS}/m_{\\rm V}|_{T=0}$ is a ratio of meson masses in PS and V channels at $T=0$.\nA temperature range is $T/T_{\\rm pc}=(0.8 - 4.0)$, where $T_{\\rm pc}$ is the\npseudo-critical temperature. We find that the temperature dependence of the\nscreening masses normalized by temperature, $M_0/T$, shows notable structure\naround $T_{\\rm pc}$, and approach $2\\pi$ at high temperature in both channels,\nwhich is consistent with twice the thermal mass of a free quark in high\ntemperature limit. The screening masses at low density are also investigated by\nusing the Taylor expansion method with respect to the quark chemical potential.\nWe find that the expansion coefficients in the leading order become positive in\nthe temperature range, and thermal and density effect on the meson\nscreening-masses becomes apparent in the quark-gluon plasma phase. The meson\nscreening-masses are also compared with the gluon (Debye) screening masses at\nfinite temperature and density."
    },
    {
        "anchor": "QCD at nonzero isospin asymmetry: We study the phase diagram and the thermodynamic properties of QCD at nonzero\nisospin asymmetry at physical quark masses with staggered quarks. In\nparticular, continuum results for the phase boundary between the normal and the\npion condensation phases and the chiral/deconfinement transition are presented.\nOur findings indicate that the pion condensation phase is restricted to\n$T\\lesssim170$~MeV for isospin chemical potentials up to 325~MeV. We also use\nthe data to test the range of validity of the Taylor expansion method and show\nfirst results for the equation of state.",
        "positive": "Study of the conformal region of the SU(3) gauge theory with domain-wall\n  fermions: We investigate the phase structure of the SU(3) gauge theory with $N_f=8$ by\nnumerical simulations employing the massless Domain-Wall fermions.Our aim is to\nstudy directly the massless quark region, since it is the most important region\nto clarify the properties of conformal theories. When the number of flavor is\nwithin the conformal window, it is claimed recently with Wilson quarks that\nthere is the conformal region at the small quark mass region in the parameter\nspace in addition to the confining phase and the deconfining phase. We study\nthe properties of the conformal region investing the spatial Polyakov loops and\nthe temporal meson propagators. Our data imply that there is the conformal\nregion, and a phase transition between the confining phase and the conformal\nregion takes place. These results are consistent with the claim that the\nconformal window is between $7$ and $16$. Progress reports on other related\nstudies are also presented."
    },
    {
        "anchor": "Chiral fermion on quantum computers: Quantum computation often suffers from artificial symmetry breaking. We\nshould strive to suppress the artifact both by theoretical and technological\nimprovements. The theoretical formalism of the lattice fermion with exact\nchiral symmetry is called the chiral fermion. In this presentation, we show how\nthe chiral fermion describes chiral physics in quantum computing. We also show\nthat, although a drawback of the chiral fermion is large computational cost,\nthere is a loophole in one dimension.",
        "positive": "Bottomonium spectrum at finite temperature: We investigate the modification of S and P wave states in the bottomonium\nspectrum above and below the deconfinement crossover temperature through their\nspectral functions obtained from the maximum entropy method. Anisotropic\nensembles with $N_f=2+1$ Wilson clover fermions with tadpole-improvement are\nused while the bottom quark is treated with an improved non-relativistic\naction. We observe significant modifications of the P wave $\\chi_{b1}$ ground\nstate directly above the crossover temperature, $T_c$, while the S wave\n$\\Upsilon$ ground state remains relatively unchanged up to temperatures of\nalmost $2T_c$. This evidence supports earlier conclusions from our FASTSUM\ncollaboration of the immediate dissociation of the P wave states above $T_c$\nand the survival of the S wave ground states up to $2T_c$."
    },
    {
        "anchor": "Applications of the Eigenmodes of the Staggered Dirac Operator: We have constructed the lowest few eigenvectors of the staggered Dirac\noperator on SU(3) gauge configurations, both quenched and dynamical. We use\nthese modes to study the topological charge and to construct approximate\nhadronic correlators.",
        "positive": "Computation of the strong coupling in QCD with two dynamical flavours: We present a non-perturbative computation of the running of the coupling\nalpha_s in QCD with two flavours of dynamical fermions in the Schroedinger\nfunctional scheme. We improve our previous results by a reliable continuum\nextrapolation. The Lambda-parameter characterizing the high-energy running is\nrelated to the value of the coupling at low energy in the continuum limit. An\nestimate of Lambda*r_0 is given using large-volume data with lattice spacings a\nfrom 0.07 fm to 0.1 fm. It translates into Lambda_{MSbar}^{(2)}=245(16)(16) MeV\n[assuming r_0=0.5 fm]. The last step still has to be improved to reduce the\nuncertainty."
    },
    {
        "anchor": "Continuum limit of the $D$ meson, $D_s$ meson and charmonium spectrum\n  from $N_f=2+1+1$ twisted mass lattice QCD: We compute masses of $D$ meson, $D_s$ meson and charmonium states using\n$N_f=2+1+1$ Wilson twisted mass lattice QCD. All results are extrapolated to\nphysical light quark masses, physical strange and charm quark masses and to the\ncontinuum. Our analysis includes states with spin $J = 0,1,2$, parity\n$\\mathcal{P} = -,+$ and in case of charmonium also charge conjugation\n$\\mathcal{C} = -,+$. Computations are based on a large set of quark-antiquark\nmeson creation operators. We investigate and quantify all sources of systematic\nerrors, including fitting range uncertainties, finite volume effects, isospin\nbreaking effects and the choice of the fitting ansatz for the combined chiral\nand continuum extrapolation such that the resulting meson masses can be\ncompared directly and in a meaningful way to experimental results. Within\ncombined statistical and systematic errors, which are between below two per\nmille and three percent, our results agree with available experimental results\nfor most of the states. In the few cases where we observe discrepancies, we\ndiscuss possible reasons.",
        "positive": "Dibaryon with highest charm number near unitarity from lattice QCD: A pair of triply charmed baryons, $\\Omega_{ccc}\\Omega_{ccc}$, is studied as\nan ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical\nlight-quark masses and the relativistic heavy quark action with the physical\ncharm quark mass. The spatial baryon-baryon correlation is related to their\nscattering parameters on the basis of the HAL QCD method. The\n$\\Omega_{ccc}\\Omega_{ccc}$ in the ${^1S_0}$ channel taking into account the\nCoulomb repulsion with the charge form factor of $\\Omega_{ccc}$ leads to the\nscattering length $a^{\\rm C}_0\\simeq -19~\\text{fm}$ and the effective range\n$r^{\\rm C}_{\\mathrm{eff}}\\simeq 0.45~\\text{fm}$. The ratio $r^{\\rm\nC}_{\\mathrm{eff}}/a^{\\rm C}_0 \\simeq -0.024$, whose magnitude is considerably\nsmaller than that of the dineutron ($-0.149$), indicates that\n$\\Omega_{ccc}\\Omega_{ccc}$ is located in the unitary regime."
    },
    {
        "anchor": "Noise, sign problems, and statistics: We show how sign problems in simulations of many-body systems can manifest\nthemselves in the form of heavy-tailed correlator distributions, similar to\nwhat is seen in electron propagation through disordered media. We propose an\nalternative statistical approach for extracting ground state energies in such\nsystems, illustrating the method with a toy model and with lattice data for\nunitary fermions.",
        "positive": "Heavy dense QCD from a 3d effective lattice theory: The cold and dense regime of the QCD phase diagram is to this day\ninaccessible to first principle lattice calculations owing to the sign problem.\nHere we present progress of an ongoing effort to probe this particularly\ndifficult regime utilising a dimensionally reduced effective lattice theory\nwith a significantly reduced sign problem. The effective theory is derived by\ncombined character and hopping expansion and is valid for heavy quarks near the\ncontinuum. We show an extension of the effective theory to order $u^5\\kappa^8$\nin the cold regime. A linked cluster expansion is applied to the effective\ntheory resulting in a consistent mechanism for handling the effective theory\nfully analytically. The new results are consistent with the ones from\nsimulations confirming the viability of analytic methods. Finally we resum the\nanalytical result which doubles the convergence region of the expansion."
    },
    {
        "anchor": "Evidence for the Role of Instantons in Hadron Structure from Lattice QCD: Cooling is used as a filter on a set of gluon fields sampling the Wilson\naction to selectively remove essentially all fluctuations of the gluon field\nexcept for the instantons. The close agreement between quenched lattice QCD\nresults with cooled and uncooled configurations for vacuum correlation\nfunctions of hadronic currents and for density-density correlation functions in\nhadronic bound states provides strong evidence for the dominant role of\ninstantons in determining light hadron structure and quark propagation in the\nQCD vacuum.",
        "positive": "A Critical Surface of Chiral-invariant System with Gauge Boson and\n  Fermions: In the chirally-invariant context of the $U_{em}(1)$ gauge interaction and\nfour-fermion interactions for ordinary and mirror fermions, the Schwinger-Dyson\nequation for the fermion self-energy function is studied on a lattice. We find\nthat a sensible infrared limit can be defined on a critical surface, which is\nconsistent with the critical line found in the continuum theory."
    },
    {
        "anchor": "Tensor renormalization of three-dimensional Potts model: We study the $q$-state Potts models on a cubic lattice in the thermodynamic\nlimit using tensor renormalization group transformations with the triad\napproximation. By computing the thermodynamic potentials, we locate the\nfirst-order phase transitions for $10 < q \\le 20$ which has not been explored\nusing any method. We also examine the efficiency of the triad approximation\nmethod in obtaining the fixed-point tensor and comment on how this can be\nimproved.",
        "positive": "Quark number susceptibility of high temperature and finite density QCD: We utilize lattice simulations of the dimensionally reduced effective field\ntheory (EQCD) to determine the quark number susceptibility of QCD at high\ntemperature ($T>2T_c$). We also use analytic continuation to obtain results at\nfinite density. The results extrapolate well from known perturbative expansion\n(accurate in extremely high temperatures) to 4d lower temperature lattice data"
    },
    {
        "anchor": "Lattice QCD approach to Nuclear Physics: We review recent progress of the HAL QCD method which was recently proposed\nto investigate hadron interactions in lattice QCD. The strategy to extract the\nenergy-independent non-local potential in lattice QCD is explained in detail.\nThe method is applied to study nucleon-nucleon, nucleon-hyperon,\nhyperon-hyperon and meson-baryon interactions. Several extensions of the method\nare also discussed.",
        "positive": "Low lying baryon spectrum with $N_f = 2+1+1$ dynamical twisted quarks: We present first results on the octet and decuplet strange baryon spectrum\nwith $N_f=2+1+1$ twisted mass quarks. We use an Osterwalder Seiler valence\nstrange quark with a mass tuned to the kaon and compare the results with those\nobtained in the unitary setup. This comparison allows to perform a first study\nof the lattice artefacts introduced by the mixed action approach. We\ninvestigate the effect of the strange and charm quarks in the sea by using two\nlattice spacings and comparing with preceding $N_f = 2$ twisted mass fermion\ncalculations."
    },
    {
        "anchor": "Electric Polarizabilities from Lattice QCD: The response of hadrons to electromagnetic probes is highly constrained by\nchiral dynamics; but, in some cases, predictions have not compared well with\nexperimental data. The lattice can be used to test the chiral electromagnetism\nof hadrons and ultimately confront experiment. We use background field\ntechniques to study the electromagnetic polarizabilities of hadrons. Focusing\non simulations in background electric fields, we present preliminary results\nfor both charged and neutral particle polarizabilities. The former are\nextracted using a novel method.",
        "positive": "Chiral Extrapolations of the $\\boldsymbol{\u03c1(770)}$ Meson in\n  $\\mathbf{N_f=2+1}$ Lattice QCD Simulations: Recent $N_f=2+1$ lattice data for meson-meson scattering in $p$-wave and\nisospin $I=1$ are analyzed using a unitarized model inspired by Chiral\nPerturbation Theory in the inverse-amplitude formulation for two and three\nflavors. Chiral extrapolations are performed that postdict phase shifts\nextracted from experiment quite well. In addition, the low-energy constants are\ncompared to the ones from a recent analysis of $N_f=2$ lattice QCD simulations\nto check for the consistency of the hadronic model used here. Some\ninconsistencies are detected in the fits to $N_f=2+1$ data, in contrast to the\nprevious analysis of $N_f=2$ data."
    },
    {
        "anchor": "Running couplings in equivariantly gauge-fixed SU(N) Yang--Mills\n  theories: In equivariantly gauge-fixed SU(N) Yang--Mills theories, the gauge symmetry\nis only partially fixed, leaving a subgroup $H\\subset SU(N)$ unfixed. Such\ntheories avoid Neuberger's nogo theorem if the subgroup $H$ contains at least\nthe Cartan subgroup $U(1)^{N-1}$, and they are thus non-perturbatively well\ndefined if regulated on a finite lattice. We calculate the one-loop beta\nfunction for the coupling $\\tilde{g}^2=\\xi g^2$, where $g$ is the gauge\ncoupling and $\\xi$ is the gauge parameter, for a class of subgroups including\nthe cases that $H=U(1)^{N-1}$ or $H=SU(M)\\times SU(N-M)\\times U(1)$. The\ncoupling $\\tilde{g}$ represents the strength of the interaction of the gauge\ndegrees of freedom associated with the coset $SU(N)/H$. We find that\n$\\tilde{g}$, like $g$, is asymptotically free. We solve the\nrenormalization-group equations for the running of the couplings $g$ and\n$\\tilde{g}$, and find that dimensional transmutation takes place also for the\ncoupling $\\tilde{g}$, generating a scale $\\tilde{\\Lambda}$ which can be larger\nthan or equal to the scale $\\Lambda$ associated with the gauge coupling $g$,\nbut not smaller. We speculate on the possible implications of these results.",
        "positive": "Three-quark potential and Abelian dominance of confinement in SU(3) QCD: We study the baryonic three-quark (3Q) potential and its Abelian projection\nin terms of the dual-superconductor picture in SU(3) quenched lattice QCD. The\nnon-Abelian SU(3) gauge theory is projected onto Abelian U(1)$^2$ gauge theory\nin the maximal Abelian gauge. We investigate the 3Q potential and its Abelian\npart for more than 300 different patterns of static 3Q systems in total at\n$\\beta=5.8$ on $16^332$ and at $\\beta=6.0$ on $20^332$ with 1000-2000 gauge\nconfigurations. For all the distances, both the 3Q potential and Abelian part\nare found to be well described by the Y ansatz, i.e., two-body Coulomb term\nplus three-body Y-type linear term $\\sigma_{3\\mathrm{Q}} L_{\\mathrm{min}}$,\nwhere $L_{\\mathrm{min}}$ is the minimum flux-tube length connecting the three\nquarks. We find equivalence between the three-body string tension\n$\\sigma_{3\\mathrm{Q}}$ and its Abelian part $\\sigma_{3\\mathrm{Q}}^{\\rm Abel}$\nwith an accuracy within a few percent deviation, i.e., $\\sigma_{3\\mathrm{Q}}\n\\simeq \\sigma_{3\\mathrm{Q}}^{\\rm Abel}$, which means Abelian dominance of the\nquark-confining force in 3Q systems."
    },
    {
        "anchor": "Sextet Model with Wilson Fermions: We present new results from our ongoing study of the SU(3) sextet model with\ntwo flavors in the two-index symmetric representation of the gauge group. In\nthe simulations use unimproved Wilson fermions to investigate the infrared\nproperties of the model. We have previously presented results for the spectrum\nof the model in the weak coupling regime. Here, to better understand the\noverall behavior of the lattice model, we map its non-trivial phase structure\nin the space of bare parameters. At strong coupling, we observe a first order\nphase transition when decreasing the bare quark mass. This first order\ntransition weakens when moving towards weaker couplings with an endpoint at a\nfinite value of the bare coupling, after which it appears to be a continuous\ntransition. We also investigate the behavior of the mass spectrum and\nscale-setting observable, as a function of the quark mass, and show that their\nqualitative behavior change significantly when moving from the strong coupling\ninto the weak coupling phase.",
        "positive": "Vector correlator and scale determination in lattice QCD: We implement a proposal made in [arXiv:1107.4388] to determine the lattice\nspacing by matching the lattice vector correlator at a reference distance scale\nwith the same correlator obtained by a dispersion relation based on the\n$R$-ratio determined experimentally. We work with the isovector current,\nrequiring a separation of the isovector hadronic final states on the\nphenomenological side. We also discuss the finite-size effect on the\ncorrelator, which must be controlled in order for the method to be applicable."
    },
    {
        "anchor": "Quark mass dependence of $\u03c0\u03c0$ scattering in isospin 0, 1, and 2\n  from lattice QCD: Using lattice QCD we extract $\\pi\\pi$ scattering amplitudes with\nisospin--0,1,2 in low partial-waves at two values of the light quark mass\ncorresponding to $m_\\pi \\sim 283$ and $330$ MeV. We confirm expectations of\nweak repulsion in isospin--2, and the presence of a narrow $\\rho$ resonance in\nisospin--1, and study the pion mass dependence of these channels. In isospin--0\nwe find that the two pion masses considered straddle the point at which the\n$\\sigma$ transitions from being a stable bound-state to being either a virtual\nbound-state or a subthreshold resonance. We discuss the ability of lattice\ncalculations like these to precisely determine the $\\sigma$ pole location when\nit is a resonance, and propose an approach in which the full complement of\namplitudes computed in this paper can be used simultaneously to provide more\nconstraint.",
        "positive": "Twisted SUSY Invariant Formulation of Chern-Simons Gauge Theory on a\n  Lattice: We propose a twisted SUSY invariant formulation of Chern-Simons theory on a\nEuclidean three dimensional lattice. The SUSY algebra to be realized on the\nlattice is the N=4 D=3 twisted algebra that was recently proposed by D'Adda et\nal.. In order to keep the manifest anti-hermiticity of the action, we introduce\noppositely oriented supercharges. Accordingly, the naive continuum limit of the\naction formally corresponds to the Landau gauge fixed version of Chern-Simons\ntheory with complex gauge group which was originally proposed by Witten. We\nalso show that the resulting action consists of parity even and odd parts with\ndifferent coefficients."
    },
    {
        "anchor": "Preliminary study of two-dimensional SU(N) Yang-Mills theory with\n  adjoint matter by Hybrid Monte Carlo approach: Two-dimensional non-abelian quantum field models provide a useful laboratory\nfor analytic and numerical investigations of quantum theories with gauge\nsymmetry. They can exhibit various features, such as charge confinement, which\nare known from D=4 theories like QCD. Several analytic predictions concerning\nthe spectra of two-dimensional systems with adjoint matter were postulated and\nnumerical results were obtained using Discrete Light Cone Quantization\ntechniques, however none of them has been checked via Monte Carlo simulations.\nIn this Letter we present two such models which are particularly interesting\nfrom the physical point of view and discuss first numerical results.",
        "positive": "Finite Volume at Two-loops in Chiral Perturbation Theory: We calculate the finite volume corrections to meson masses and decay\nconstants in two and three flavour Chiral Perturbation Theory to two-loop\norder. The analytical results are compared with the existing result for the\npion mass in two-flavour ChPT and the partial results for the other quantities.\nWe present numerical results for all quantities."
    },
    {
        "anchor": "Thermodynamics from Monte Carlo Hamiltonian: We construct an effective low-energy Hamiltonian from the classical action\nvia Monte Carlo with importance sampling. We use Monte Carlo (i) to compute\nmatrix elements of the transition amplitude and (ii) to construct\nstochastically a basis. The MC Hamiltonian allows to obtain energies and wave\nfunctions of low-lying states. It allows also to compute thermodynamical\nobservables in some temperature window (starting from temperature zero). We\npresent examples from lattice field theory (Klein-Gordon model).",
        "positive": "Measurement of thermodynamics using gradient flow: We analyze bulk thermodynamics and correlation functions of the\nenergy-momentum tensor in pure Yang-Mills gauge theory using the\nenergy-momentum tensor defined by the gradient flow and small flow time\nexpansion. Our results on thermodynamic observables are consistent with those\nobtained by the conventional integral method. The analysis of the correlation\nfunction of total energy supports the energy conservation. It is also addressed\nthat these analyses with gradient flow require less statistics compared with\nthe previous methods. All these results suggest that the energy-momentum tensor\ncan be successfully defined and observed on the lattice with moderate numerical\ncosts with the gradient flow."
    },
    {
        "anchor": "Investigating and Optimizing the Chiral Properties of Lattice Fermion\n  Actions: We study exceptional modes of both the Wilson and the clover action in order\nto understand why quenched clover spectroscopy suffers so severely from\nexceptional configurations. We show that, in contrast to the case of the Wilson\naction, a large clover coefficient can make the exceptional modes extremely\nlocalized and thus very sensitive to short distance fluctuations. We describe a\nway to optimize the chiral behavior of Wilson-type lattice fermion actions by\nstudying their low energy real eigenmodes. We find a candidate action, the\nclover action with fat links with a tuned clover term. We present a calculation\nof spectroscopy and matrix elements at Wilson gauge coupling beta=5.7. When\ncompared to simulations with the standard (nonperturbatively improved) clover\naction at small lattice spacing, the action shows good scaling behavior, with\nan apparent great reduction in the number of exceptional configurations.",
        "positive": "Computer Aided Series Expansions for Critical Phenomena: Under quite general conditions critical phenomena can be described with high\norder linked cluster expansions. The coefficients of the series admit a\ngraphical expansion that is generated with the aid of computers. Our\ngeneralization of linked cluster expansions from an infinite to a finite volume\nallows to perform a finite size scaling analysis. We also indicate a\ngeneralization to Dynamical Linked Cluster Expansions with possible\napplications to spin glasses and neural networks with coupled spin and\ninteraction dynamics."
    },
    {
        "anchor": "The confining color field in SU(3) gauge theory: We extend a previous numerical study of SU(3) Yang-Mills theory in which we\nmeasured the spatial distribution of all components of the color fields\nsurrounding a static quark-antiquark pair for a wide range of quark-antiquark\nseparations, and provided evidence that the simulated gauge invariant\nchromoelectric field can be separated into a Coulomb-like 'perturbative' field\nand a 'non-perturbative' field, identified as the confining part of the SU(3)\nflux tube field. In this paper we hypothesize that the fluctuating color fields\nnot measured in our simulations do not contribute to the string tension. Under\nthis assumption the string tension is determined by the color fields we\nmeasure, which form a tensor $F_{\\mu \\nu}$ pointing in a single direction in\ncolor space. We call this the Maxwell mechanism of confinement. We provide an\nadditional procedure to isolate the non-perturbative (confining) field. We then\nextract the string tension from a stress energy-momentum tensor $T_{\\mu \\nu}$\nhaving the Maxwell form, constructed from the non-perturbative part of the\ntensor $F_{\\mu \\nu}$ obtained from our simulations. To test our hypothesis we\ncalculate the string tension from our simulations of the color fields for ten\nvalues of the quark-antiquark separation ranging from 0.37 fm to 1.2 fm. We\nalso calculate the spatial distributions of the energy-momentum tensor $T_{\\mu\n\\nu}$ surrounding static quarks for this range of separations, and we compare\nthese distributions with those obtained from direct simulations of the\nenergy-momentum tensor in SU(3) Yang-Mills theory.",
        "positive": "Relativistic Lattice Boltzmann Methods: Theory and Applications: We present a systematic account of recent developments of the relativistic\nLattice Boltzmann method (RLBM) for dissipative hydrodynamics. We describe in\nfull detail a unified, compact and dimension-independent procedure to design\nrelativistic LB schemes capable of bridging the gap between the\nultra-relativistic regime, $k_{\\rm B} T \\gg mc^2$, and the non-relativistic\none, $k_{\\rm B} T \\ll mc^2$. We further develop a systematic derivation of the\ntransport coefficients as a function of the kinetic relaxation time in\n$d=1,2,3$ spatial dimensions. The latter step allows to establish a\nquantitative bridge between the parameters of the kinetic model and the\nmacroscopic transport coefficients. This leads to accurate calibrations of\nsimulation parameters and is also relevant at the theoretical level, as it\nprovides neat numerical evidence of the correctness of the Chapman-Enskog\nprocedure. We present an extended set of validation tests, in which simulation\nresults based on the RLBMs are compared with existing analytic or semi-analytic\nresults in the mildly-relativistic ($k_{\\rm B} T \\sim mc^2$) regime for the\ncase of shock propagations in quark-gluon plasmas and laminar electronic flows\nin ultra-clean graphene samples. It is hoped and expected that the material\ncollected in this paper may allow the interested readers to reproduce the\npresent results and generate new applications of the RLBM scheme."
    },
    {
        "anchor": "Numerical experiments using deflation with the HISQ action: We report on numerical experiments using deflation to compute quark\npropagators for the highly improved staggered quark (HISQ) action. The method\nis tested on HISQ gauge configurations, generated by the MILC collaboration,\nwith lattice spacings of 0.15 fm, with a range of volumes, and sea quark masses\ndown to the physical quark mass.",
        "positive": "The infrared limit of QCD effective string: Some model-independent properties of the effective string of gauge field\nsystems in the confining phase , for very large quark separations, are\ndescribed in terms of two-dimensional conformal field theories. The constraints\ninduced by the gauge theory at the boundaries of the effective string induce a\nCoulomb- like term in the interquark potential which is universal, but\ndifferent from the one proposed by L\\\"uscher. Some universal relations among\nthe string tension, the thickness of the colour flux tube, the location of the\ndeconfining temperature and a lower bound of the glueball spectrum are\ndiscussed. (Lectures given at the XXXII Cracow School of Theoretical Physics,\nZakopane, Poland 2-12 June 1992)"
    },
    {
        "anchor": "Wilson Fermions with Four Fermion Interactions: We present a lattice study of a four fermion theory, known as Nambu\nJona-Lasinio (NJL) theory, via Wilson fermions. Four fermion interactions\nnaturally occur in several extensions of the Standard Model as a low energy\nparameterisation of a more fundamental theory. In models of dynamical\nelectroweak symmetry breaking these operators, at an effective level, are used\nto endow the Standard Model fermions with masses. Furthermore these operators,\nwhen sufficiently strong, can drastically modify the fundamental composite\ndynamics by, for example, turning a strongly coupled infrared conformal theory\ninto a (near) conformal one with desirable features for model building. As\nfirst step, we study spontaneous chiral symmetry breaking for the lattice\nversion of the NJL model.",
        "positive": "SU(2) gauge theory with $N_f=24$ quarks at non-zero mass: We study SU(2) gauge field theory with $N_f=24$ quarks. The theory is\nasymptotically non-free and, at vanishing quark mass, governed by a Gaussian\nfixed point at long distances. On the other hand, at non-zero quark mass the\nquarks are expected to decouple at long distances and the system behaves like\nconfining pure gauge SU(2) theory. We study the mass spectrum of the theory as\nthe quark mass is varied and obtain scaling laws for meson masses and string\ntension. We also measure the evolution of the coupling constant at non-zero\nquark mass with gradient flow method. We observe unambiguously the decoupling\nof the quarks with the associated change of evolution of the coupling constant."
    },
    {
        "anchor": "Strings and Branes in Nonabelian Gauge Theory: It is an old speculation that SU(N) gauge theory can alternatively be\nformulated as a string theory. Recently this subject has been revived, in the\nwake of the discovery of D-branes. In particular, it has been argued that at\nleast some conformally invariant cousins of the theory have such a string\nrepresentation. This is a pedagogical introduction to these developments for\nnon-string theorists. Some of the existing arguments are simplified.",
        "positive": "Low-lying fermion modes, topology and light hadrons in quenched QCD: We explore the properties of low lying eigenmodes of fermions in the quenched\napproximation of lattice QCD. The fermion action is a recently proposed overlap\naction and has exact chiral symmetry. We find that chiral zero-eigenvalue modes\nare localized in space and their positions correlate strongly with the\nlocations (as defined through the density of pure gauge observables) of\ninstantons of the appropriate charge. Nonchiral modes are also localized with\npeaks which are strongly correlated with the positions of both charges of\ninstantons. These correlations slowly die away as the fermion eigenvalue rises.\nCorrelators made of quark propagators restricted to these modes closely\nreproduce ordinary hadron correlators at small quark mass in many channels. Our\nresults are in qualitative agreement with the expectations of instanton liquid\nmodels."
    },
    {
        "anchor": "Chiral extrapolations of nucleon properties from lattice QCD: We report on recent work about the study of quark mass dependence of nucleon\nmagnetic moments and axial-vector coupling constant. We examine the feasibility\nof chiral effective field theory methods for the extrapolation of lattice QCD\ndata obtained at relative large pion masses down to the physical values.",
        "positive": "A Dedicated Computer for Ising-like Spin Glass Models: We present a parallel machine, based on programmable devices, dedicated to\nsimulate spin glass models with Z2 variables and short range interaction. A\nworking prototype is described for two lattices containing 312x312 spins each\nwith an update time of 50 ns per spin. The final version of the three\ndimensional parallel machine is discussed with spin update time up to 312 ps."
    },
    {
        "anchor": "Gauge-invariant Renormalization Scheme in QCD: Application to fermion\n  bilinears and the energy-momentum tensor: We consider a gauge-invariant, mass-independent prescription for\nrenormalizing composite operators, regularized on the lattice, in the spirit of\nthe coordinate space (X-space) renormalization scheme. The prescription\ninvolves only Green's functions of products of gauge-invariant operators,\nsituated at distinct space-time points, in a way as to avoid potential contact\nsingularities. Such Green's functions can be computed nonperturbatively in\nnumerical simulations, with no need to fix a gauge: thus, renormalization to\nthis \"intermediate\" scheme can be carried out in a completely nonperturbative\nmanner.\n  Expressing renormalized operators in the $\\overline{\\rm MS}$ scheme requires\nthe calculation of corresponding conversion factors. The latter can only be\ncomputed in perturbation theory, by the very nature of the $\\overline{\\rm MS}$;\nhowever, the computations are greatly simplified by virtue of the following\nattributes: i) In the absense of operator mixing, they involve only massless,\ntwo-point functions; such quantities are calculable to very high perturbative\norder. ii) They are gauge invariant; thus, they may be computed in a convenient\ngauge. iii) Where operator mixing may occur, only gauge-invariant operators\nwill appear in the mixing pattern: Unlike other schemes, involving mixing with\ngauge-variant operators (which may contain ghost fields), the mixing matrices\nin the present scheme are greatly reduced. Still, computation of some\nthree-point functions may not be altogether avoidable.\n  We exemplify the procedure by computing, to lowest order, the conversion\nfactors for fermion bilinear operators of the form $\\bar\\psi\\Gamma\\psi$ in QCD.\nWe also employ the gauge-invariant scheme in the study of mixing between gluon\nand quark energy-momentum tensor operators: We compute to one loop the\nconversion factors relating the nonperturbative mixing matrix to the\n$\\overline{\\rm MS}$ scheme.",
        "positive": "DEPENDENCE OF THE CURRENT RENORMALISATION CONSTANTS ON THE QUARK MASS: We study the behaviour of the vector and axial current renormalisation\nconstants $Z_V$ and $Z_A$ as a function of the quark mass, $m_q$. We show that\nsizeable $O(am_q)$ and $O(g_0^2 a m_q)$ systematic effects are present in the\nWilson and Clover cases respectively. We find that the prescription of\nKronfeld, Lepage and Mackenzie for correcting these artefacts is not always\nsuccessful."
    },
    {
        "anchor": "Hamiltonian study of Supersymmetric Yang-Mills Quantum Mechanics: New results obtained within the recently developed approach to supersymmetric\nquantum mechanical systems are presented. The method does not suffer from the\nsign problem in any dimensions and is capable to provide any quantum observable\nwith controllable systematic error. Discussed results include: the spectrum and\nWitten index of the D=4 system, and the spectrum of zero volume glueballs in\nhigher 3 < D < 11 dimensions.",
        "positive": "Finite Density QCD: a New Approach: We introduce a new approach to analyze the phase diagram of QCD at finite\nchemical potential and temperature, test it in the Gross-Neveu model at finite\nbaryon density, and apply it to the study of the chemical potential-temperature\nphase diagram of QCD with four degenerate flavors of Kogut-Susskind type."
    },
    {
        "anchor": "Hadron interactions in lattice QCD: Progress on the potential method, recently proposed to investigate hadron\ninteractions in lattice QCD, is reviewed. The strategy to extract the potential\nin lattice QCD is explained in detail. The method is applied to extract $NN$\npotentials, hyperon potentials and the meson-baryon potentials. A theoretical\ninvestigation is made to understand the origin of the repulsive core using the\noperator product expansion. Some recent extensions of the method are also\ndiscussed.",
        "positive": "The $\\big\\langle A^2 \\big\\rangle$ Asymmetry and Longitudinal Propagator\n  in Lattice $SU(2)$ Gluodynamics at $T\\simeq T_c$: We study numerically the chromoelectric-chromomagnetic asymmetry of the\ndimension two gluon condensate as well as the longitudinal gluon propagator at\n$T\\simeq T_c$ in the Landau-gauge $SU(2)$ lattice gauge theory. We show that\nsubstantial correlation between the asymmetry and the Polyakov loop as well as\nthe correlation between the longitudinal propagator and the Polyakov loop pave\nthe way to studies of the critical behavior of the asymmetry and the\nlongitudinal propagator. The respective values of critical exponents and\namplitudes are evaluated."
    },
    {
        "anchor": "Scaled Affine Quantization of $\\varphi^{12}_3$ is Nontrivial: We prove through Monte Carlo analysis that the covariant euclidean scalar\nfield theory, $\\varphi^r_n$, where $r$ denotes the power of the interaction\nterm and $n = s + 1$ where $s$ is the spatial dimension and $1$ adds imaginary\ntime, such that $r = 12, n = 3$ can be acceptably quantized using scaled affine\nquantization and the resulting theory is nontrivial, unlike what happens using\ncanonical quantization when the system is plagued by asymptotic freedom.",
        "positive": "Spectral properties of the non-hermitian Wilson-Dirac operator in the\n  Schroedinger functional: We report on some preparatory investigations for the simulation of the QCD\nSchroedinger functional with a non-hermitian polynomial hybrid Monte Carlo\nalgorithm. The complex spectrum of the non-hermitean free operator with SF\nboundary condititons is computed semianalytically. Then it is shown how one can\nobtain relevant information on the boundary of the spectral domain also in the\npresence of nontrivial gaugefields by monitoring the behavior of polynomials in\nthe Wilson operator applied on random vectors."
    },
    {
        "anchor": "Study of the Roberge-Weiss phase caused by external uniform classical\n  electric field using lattice QCD approach: The effect of an external electric field on the quark matter is an important\nquestion due to the presence of strong electric fields in heavy ion collisions.\nIn the lattice QCD approach, the case of a real electric field suffers from the\n`sign problem', and a classical electric field is often used similar as the\ncase of chemical potential. Interestingly, in axial gauge a uniform classical\nelectric field actually can correspond to an inhomogeneous imaginary chemical\npotential that varies with coordinate. On the other hand, with imaginary\nchemical potential, Roberge-Weiss~(R-W) phase transition occurs. In this work,\nthe case of a uniform classical electric field is studied by using lattice QCD\napproach, with the emphasis on the properties of the R-W phase. Novel phenomena\nshow up at high temperatures. It is found that, the chiral condensation\noscillates with $z$ at high temperatures, and so is the absolute value of the\nPolyakov loop. It is verified that the charge density also oscillates with $z$\nat high temperatures. The Polyakov loop can be described by an ansatz $A_p+\\sum\n_{q=u,d} C_q\\exp\\left(L_{\\tau} Q_q iazeE_z\\right)$, where $A_p$ is a complex\nnumber and $C_d>0,C_u\\geq 0$ are real numbers that are fitted for different\ntemperatures and electric field strengths. As a consequence, the behavior of\nthe phase of Polyakov loop is different depending on whether the Polyakov loop\nencloses the origin, which implies a possible phase transition.",
        "positive": "Perturbative calculation of $Z_q$ at the one-loop level using\n  HYP-smeared staggered quarks: We present matching factors for $Z_q$ calculated perturbatively at the\none-loop level with improved staggered quarks. We calculate $Z_q$ with\nHYP-smeared staggered quarks and Symanzik-improved gluons using both RI-MOM and\nRI$'$-MOM schemes. We compare the results with those obtained using the\nnonperturbative renormalization (NPR) method."
    },
    {
        "anchor": "Localized Modes in the IR Phase of QCD: Infrared (IR) dimension function $d_\\text{IR}(\\lambda)$ characterizes the\nspace effectively utilized by QCD quarks at Dirac scale $\\lambda$, and\nindirectly the space occupied by glue fields. It was proposed that its\nnon-analytic behavior in thermal infrared phase reflects the separation of QCD\nsystem into an IR component and an independent bulk. Here we study the\n``plateau modes\" in IR component, whose dimensional properties were puzzling.\nIndeeed, in the recent metal-to-critical scenario of transition to IR phase,\nthis low-dimensional plateau connects the Anderson-like mobility edge\n$\\lambda_\\text{IR}=0$ in Dirac spectrum with mobility edges $\\pm\n\\lambda_\\text{A}$. For this structure to be truly Anderson-like, plateau modes\nhave to be exponentially localized, implying that both the effective distances\n$L_\\text{eff} \\propto L^\\gamma$ and the effective volumes $V_\\text{eff} \\propto\nL^{d_\\text{IR}}$ in these modes grow slower than any positive power of IR\ncutoff $L$. Although $\\gamma=0$ was confirmed in the plateau, it was found that\n$d_\\text{IR}\\approx 1$. Here we apply the recently proposed multidimension\ntechnique to the problem. We conclude that a plateau mode of pure-glue QCD at\nUV cutoff $a \\!=\\! 0.085\\,$fm occupies a subvolume of IR dimension zero with\nprobability at least 0.9999, substantiating this aspect of metal-to-critical\nscenario to a respective degree.",
        "positive": "On the rigid string contribution to the interquark potential: Owing to Lorentz invariance, the leading terms in the effective action\ndescribing the low-energy dynamics of flux tubes in a confining gauge theory\nare universal. Besides the terms corresponding to the Nambu-Goto action,\nLorentz invariance also allows terms describing a \"rigid string\", proposed long\nago by Kleinert and Polyakov as a model for confinement in a dual\nsuperconductor scenario. In this contribution we discuss some of the\nnon-trivial properties of this type of string and evaluate analytically the\ncorrections to the interquark potential induced by extrinsic curvature terms\nappearing in the rigid string action."
    },
    {
        "anchor": "Sp(4) gauge theories on the lattice: $N_f=2$ dynamical fundamental\n  fermions: We perform lattice studies of the gauge theory with Sp(4) gauge group and two\nflavours of (Dirac) fundamental matter. The global SU(4) symmetry is\nspontaneously broken by the fermion condensate. The dynamical Wilson fermions\nin the lattice action introduce a mass that breaks the global symmetry also\nexplicitly. The resulting pseudo-Nambu-Goldstone bosons describe the\nSU(4)/Sp(4) coset, and are relevant, in the context of physics beyond the\nStandard Model, for composite Higgs models. We discuss scale setting, continuum\nextrapolation and finite volume effects in the lattice theory. We study mesonic\ncomposite states, which span representations of the unbroken Sp(4) global\nsymmetry, and we measure masses and decay constants of the (flavoured) spin-0\nand spin-1 states accessible to the numerical treatment, as a function of the\nfermion mass. With help from the effective field theory treatment of such\nmesons, we perform a first extrapolation towards the massless limit. We assess\nour results by critically comparing to the literature on other models and to\nthe quenched results, and we conclude by outlining future avenues for further\nexploration. The results of our spectroscopic analysis provide new input data\nfor future phenomenological studies in the contexts of composite Higgs models,\nand of dark matter models with a strongly coupled dynamical origin.",
        "positive": "Finite-volume effects in the muon anomalous magnetic moment on the\n  lattice: We investigate finite-volume effects in the hadronic vacuum polarization,\nwith an eye toward the corresponding systematic error in the muon anomalous\nmagnetic moment. We consider both recent lattice data as well as lowest-order,\nfinite-volume chiral perturbation theory, in order to get a quantitative\nunderstanding. Even though leading-order chiral perturbation theory does not\nprovide a good description of the hadronic vacuum polarization, it turns out\nthat it gives a good representation of finite-volume effects. We find that\nfinite-volume effects cannot be ignored when the aim is a few percent level\naccuracy for the leading-order hadronic contribution to the muon anomalous\nmagnetic moment, even when using ensembles with $m_\\pi L> 4$ and $m_\\pi \\sim\n200$ MeV."
    },
    {
        "anchor": "Emergent phenomena from centre vortices in dynamical QCD: Quark confinement and dynamical chiral symmetry breaking are two of the most\nimportant emergent properties of the theory of quantum chromodynamics. We\nreview recent results studying centre vortices in SU(3) lattice gauge theory\nwith dynamical quarks. Through a vortex identification procedure,\nvortex-removed and vortex-only fields are obtained from the usual Monte Carlo\ngenerated gauge fields. Several comparisons between the untouched fields and\nthe vortex-modified fields support the notion that centre vortices are\nfundamental to both confinement and dynamical chiral symmetry breaking in full\nQCD.",
        "positive": "Full QCD with the L\u00fcscher local bosonic action: We investigate L\\\"uscher's method of including dynamical Wilson fermions in a\nlattice simulation of QCD with two quark flavours. We measure the accuracy of\nthe approximation by comparing it with Hybrid Monte Carlo results for gauge\nplaquette and Wilson loops. We also introduce an additional global Metropolis\nstep in the update. We show that the complexity of L\\\"uscher's algorithm\ncompares favourably with that of the Hybrid Monte Carlo."
    },
    {
        "anchor": "Searching for the BCS phase at nonzero isospin asymmetry: According to perturbation theory predictions, QCD matter in the\nzero-temperature, high-density limits of QCD at nonzero isospin chemical\npotential is expected to be in a superfluid Bardeen-Cooper-Schrieffer (BCS)\nphase of $u$ and $\\bar{d}$ Cooper pairs. It is also expected, on symmetry\ngrounds, that such phase connects via an analytical crossover to the phase with\nBose-Einstein condensation (BEC) of charged pions at $\\mu_\\text{I}\\geq\nm_\\pi/2$. With lattice results, showing some indications that the deconfinement\ncrossover also smoothly penetrates the BEC phase, the conjecture was made that\nthe former connects continuously to the BEC-BCS crossover. We compute the\nspectrum of the Dirac operator, and use generalized Banks-Casher relations, to\ntest this conjecture and identify signatures of the superfluid BCS phase.",
        "positive": "The QCD deconfinement transition for heavy quarks and all baryon\n  chemical potentials: Using combined strong coupling and hopping parameter expansions, we derive an\neffective three-dimensional theory from thermal lattice QCD with heavy Wilson\nquarks. The theory depends on traced Polyakov loops only and correctly reflects\nthe centre symmetry of the pure gauge sector as well as its breaking by finite\nmass quarks. It is valid up to certain orders in the lattice gauge coupling and\nhopping parameter, which can be systematically improved. To its current order\nit is controlled for lattices up to N_\\tau\\sim 6 at finite temperature. For\nnonzero quark chemical potentials, the effective theory has a fermionic sign\nproblem which is mild enough to carry out simulations up to large chemical\npotentials. Moreover, by going to a flux representation of the partition\nfunction, the sign problem can be solved. As an application, we determine the\ndeconfinement transition and its critical end point as a function of quark mass\nand all chemical potentials."
    },
    {
        "anchor": "Conformal or confining -- results from lattice gauge theory for\n  higher-representation gauge theories: We have calculated the running coupling in SU(2), SU(3), and SU(4) gauge\ntheories to see whether they have infrared fixed points. An infrared fixed\npoint means no confinement: It means that the long-distance physics is\nconformal, without a mass scale and indeed without a particle spectrum. All\nthese theories run slowly in perturbation theory, so a nonperturbative\ndetermination is interesting.",
        "positive": "An Analytic Variational Study of the Mass Spectrum in 2+1 Dimensional\n  SU(3) Hamiltonian Lattice Gauge Theory: We calculate the masses of the lowest lying eigenstates of improved SU(2) and\nSU(3) lattice gauge theory in 2+1 dimensions using an analytic variational\napproach. The ground state is approximated by a one plaquette trial state and\nmass gaps are calculated in the symmetric and antisymmetric sectors by\nminimising over a suitable basis of rectangular states."
    },
    {
        "anchor": "Fighting the sign problem in a chiral random matrix model with contour\n  deformations: We studied integration contour deformations in the chiral random matrix\ntheory of Stephanov with the goal of alleviating the finite-density sign\nproblem. We considered simple ans\\\"atze for the deformed integration contours,\nand optimized their parameters. We find that optimization of a single parameter\nmanages to considerably improve on the severity of the sign problem. We show\nnumerical evidence that the improvement achieved is exponential in the degrees\nof freedom of the system, i.e., the size of the random matrix. We also compare\nthe optimization method with contour deformations coming from the holomorphic\nflow equations.",
        "positive": "Wigner - Weyl formalism and the propagator of Wilson fermions in the\n  presence of varying external electromagnetic field: We develop Wigner - Weyl formalism for the lattice models. For the\ndefiniteness we consider Wilson fermions in the presence of $U(1)$ gauge field.\nThe given technique reduces calculation of the two point fermionic Green\nfunction to solution of the Groenewold equation. It relates Wigner\ntransformation of the Green function with the Weyl symbol $Q_W$ of Wilson Dirac\noperator. We derive the simple expression for $Q_W$ in the presence of varying\nexternal $U(1)$ gauge field. Next, we solve the Groenewold equation to all\norders in powers of the derivatives of $Q_W$. Thus the given technique allows\nto calculate the fermion propagator in the lattice model with Wilson fermions\nin the presence of arbitrary background electromagnetic field. The\ngeneralization of this method to the other lattice models is straightforward."
    },
    {
        "anchor": "Confronting axial-vector form factor from lattice QCD with MINERvA\n  antineutrino-proton data: We compare recent MINERvA antineutrino-hydrogen charged-current measurements\nto phenomenological predictions of the axial-vector form factor based on fits\nto all available electron scattering and deuterium bubble-chamber data and to\nrepresentative lattice-QCD (LQCD) determination by the PNDME Collaboration.\nWhile there is $1$--$2\\sigma$ agreement in the cross section with MINERvA data\nfor each bin in $Q^2$, we identify three regions with different relevance and\nopportunity for LQCD predictions. For $Q^2 \\lesssim 0.2~\\mathrm{GeV}^2$, the\nphenomenological extractions have large number of data points and LQCD is\ncompetitive, while MINERvA data have large errors. For $0.2~\\mathrm{GeV}^2\n\\lesssim Q^2 \\lesssim 1~\\mathrm{GeV}^2$, LQCD is competitive with the MINERvA\ndetermination, and both give values larger than from phenomenological\nextraction. For $Q^2 > 1~\\mathrm{GeV}^2$, the MINERvA data are the most\nprecise. Our analysis indicates that with improving precision of MINERvA-like\nexperiments and LQCD data, the uncertainty in the nucleon axial-vector form\nfactor will be steadily reduced.",
        "positive": "Leptonic decay-constant ratio $f_K/f_\u03c0$ from lattice QCD using 2+1\n  clover-improved fermion flavors with 2-HEX smearing: We present a calculation of the leptonic decay-constant ratio $f_K/f_\\pi$ in\n2+1 flavor QCD. Our data set includes five lattice spacings and pion masses\nreaching down below the physical one. Special emphasis is placed on a careful\nstudy of all systematic uncertainties, especially the continuum extrapolation.\nOur result is perfectly compatible with the first-row unitarity constraint of\nthe Standard Model."
    },
    {
        "anchor": "Overlap: The overlap formulation of regulated vectorial and chiral gauge theories is\nreviewed. Ostensibly new constructions, based on the Ginsparg-Wilson relation\nare essentially just overlap with new notation. At present there exists no\nsatisfactory realization of chiral symmetries outside perturbation theory which\nis structurally different from the overlap.",
        "positive": "Hopping expansion as a tool for handling dual variables in lattice\n  models: The hopping expansion of 8-vertex models in their Grassmann representation is\nstudied. We use the functional similarity of the Ising model in this expansion\nwith the hopping expansion of 2-D Wilson fermions to show that the lattice\nfermions are equivalent to the Self-avoiding Loop Model at bending rigidity\n1/sqrt{2}."
    },
    {
        "anchor": "Nucleon form factors and moments of parton distributions in twisted mass\n  lattice QCD: We present results on the electroweak form factors and on the lower moments\nof parton distributions of the nucleon, within lattice QCD using two dynamical\nflavors of degenerate twisted mass fermions. Results are obtained on lattices\nwith three different values of the lattice spacings, namely a=0.089 fm, a=0.070\nfm and a=0.056 fm, allowing the investigation of cut-off effects. The volume\ndependence is examined by comparing results on two lattices of spatial length\nL=2.1 fm and L=2.8 fm. The simulations span pion masses in the range of 260-470\nMeV. Our results are renormalized non-perturbatively and the values are given\nin the MS-scheme at a scale mu=2 GeV.",
        "positive": "Abelian gauge fields coupled to simplicial quantum gravity: We study the coupling of Abelian gauge theories to four-dimensional\nsimplicial quantum gravity. The gauge fields live on dual links. This is the\ncorrect formulation if we want to compare the effect of gauge fields on\ngeometry with similar effects studied so far for scalar fields. It shows that\ngauge fields couple equally weakly to geometry as scalar fields, and it offers\nan understanding of the relation between measure factors and Abelian gauge\nfields observed so-far."
    },
    {
        "anchor": "Spectrum of Trace Deformed Yang-Mills Theories: In this paper we study, by means of numerical simulations, the behaviour of\nthe scalar glueball mass and the ground state of the torelon for trace deformed\nYang-Mills theory defined on $ \\mathbb{R}^3\\times S^1$, in which center\nsymmetry is recovered even at small compactification radii. We find, by\ninvestigating both $SU(3)$ and $SU(4)$ pure gauge theories, that the glueball\nmass computed in the deformed theory, when center symmetry is recovered, is\ncompatible with its value at zero temperature and does not show any significant\ndependence on the compactification radius; moreover, we establish a connection\nbetween the deformation parameter and an effective compactification size, which\nworks well at least for small deformations. In addition, we observe that the\nground state of the torelon which winds around the small traced deformed circle\nwith size $l$ acquires a pleateau for large values of the strength $h$, with\nvalues which are compatible with a $1/l$ behavior but, on the other hand, are\nstill not in complete agreement with the asymptotic semiclassical large-$N$\npredictions.",
        "positive": "A Possible Lattice Chiral Gauge Theory: We analyze the dynamics of an $SU_L(2)\\otimes U_R(1)$ chiral gauge theory on\na lattice with a large multifermion coupling $1\\ll g_2 < \\infty$. It is shown\nthat no spontaneous symmetry breaking occurs; the ``spectator'' fermion\n$\\psi_R(x)$ is a free mode; doublers are decoupled as massive Dirac fermions\nconsistently with the chiral gauge symmetry. Whether right-handed three-fermion\nstates disappear and chiral fermions emerge in the low-energy limit are\ndiscussed. Provided right-handed three-fermion states disappear, we discuss the\nchiral gauge coupling, Ward identities, the gauge anomaly and anomalous\n$U_L(1)$ global current within the gauge-invariant prescription of\nrenormalization of the gauge perturbation theory."
    },
    {
        "anchor": "Relativistic Heavy Quark Effective Action: We study the fermion action needed to accurately describe the low energy\nphysics of systems including heavy quarks in lattice QCD even when the heavy\nfermion mass $m$ is on the order of, or larger than, the inverse lattice\nspacing: $m \\ge 1/a$. We carry out an expansion through first order in $|\\vec\np| a$ (where $\\vec p$ is the heavy quark momentum) and all orders in $ma$,\nrefining the analysis of the Fermilab and Tsukuba groups. We demonstrate that\nthe spectrum of heavy quark bound states can be determined accurately through\n$|\\vec p| a$ and $(ma)^n$ for arbitrary exponent $n$ by using a lattice action\ncontaining only three unknown coefficients: $m_0$, $\\zeta$ and $c_P$ (a\ngeneralization of $c_{SW}$), which are functions of $ma$. In a companion paper,\nwe show how these three coefficients can be precisely determined using\nnon-perturbative techniques.",
        "positive": "Topology in QCD: I review recent (and some not so recent) results on the topological\nsusceptibility (with and without fermions), the eta-prime mass, topology and\nchiral symmetry breaking, vacuum topological structure, and the possible role\nof instantons in confinement."
    },
    {
        "anchor": "Constraints of kinematic bosonization in two and higher dimensions: Contrary to the common wisdom, local bosonizations of fermionic systems exist\nin higher dimensions. Interestingly, resulting bosonic variables must satisfy\nlocal constraints of a gauge type. They effectively replace long distance\nexchange interactions. In this work we study in detail the properties of such a\nsystem which was proposed a long time ago. In particular, dependence of the\nconstraints on lattice geometry and fermion multiplicity is further elaborated\nand is now classified for all two dimensional, rectangular lattices with\narbitrary sizes. For few small systems the constraints are solved analytically\nand the complete spectra of reduced spin hamiltonias are shown to agree with\nthe original fermionic ones. The equivalence is extended to fermions in an\nexternal Wegner $Z_2$ field. It is also illustrated by an explicit calculation\nfor a particular configuration of Wegner variables. Finally, a possible\nconnection with the recently proposed web of dualities is discussed.",
        "positive": "Thermodynamics of Lattice QCD with massless quarks and chiral 4-fermion\n  interactions: We have simulated lattice QCD with an irrelevant 4-fermion interaction and 2\nzero mass quarks. The chiral phase transition is observed to be second order\nand we discuss extraction of critical exponents."
    },
    {
        "anchor": "New Results and Long-standing Questions in Finite Temperature QCD: We review recent results on QCD at finite temperature. In particular we will\ndiscuss the chiral phase transition in two flavour QCD and new results on the\nexcitation spectrum in the plasma phase of QCD.",
        "positive": "Non-Gaussian fixed point candidates in the 4D compact U(1) gauge\n  theories: Some interesting nonperturbative properties of the strongly coupled 4D\ncompact U(1) lattice gauge theories, both without and with matter fields, are\npointed out. We demonstrate that the pure gauge theory has a non-Gaussian fixed\npoint with $\\nu = 0.365(8)$ at the second order confinement-Coulomb phase\ntransition. Thus a non-asymptotic free and nontrivial continuum limit of this\ntheory, and of its various dual equivalents, in particular of a special case of\nthe effective string theory, can be constructed. Including a scalar matter\nfield (compact scalar QED), we confirm the Gaussian behavior at the endpoint of\nthe Higgs phase transition line. In the theory with both scalar and fermion\nmatter fields, we demonstrate the existence of a tricritical point. Here, the\nchiral symmetry is broken, and the mass of unconfined composite fermions is\ngenerated dynamically. Appart from the Goldstone bosons, the spectrum contains\nalso a massive scalar. This resembles the Higgs-Yukawa sector of the SM, albeit\nof dynamical origin, like the Nambu--Jona-Lasinio model. However, the scaling\nbehavior is different from that in the NJL model and the nonperturbative\nrenormalizability might thus be possible."
    },
    {
        "anchor": "Another look at the three-gluon vertex in the minimal Landau gauge: The lattice three-gluon vertex in the Landau gauge is revisited using a large\nphysical volume $\\sim(8\\textrm{fm})^4$ and a large statistical ensemble. The\nimproved calculation explores the symmetries of the hypercubic lattice to\nreduce the statistical uncertainties and addresses the evaluation of the\nlattice artefacts. Special attention is given to the low energy behaviour of\nthe vertex and its relation to ghost dominance.",
        "positive": "Locality and Statistical Error Reduction on Correlation Functions: We propose a multilevel Monte-Carlo scheme, applicable to local actions,\nwhich is expected to reduce statistical errors on correlation functions. We\ngive general arguments to show how the efficiency and parameters of the\nalgorithm are determined by the low-energy spectrum. As an application, we\nmeasure the euclidean-time correlation of pairs of Wilson loops in SU(3) pure\ngauge theory with constant relative errors. In this case the ratio of the new\nmethod's efficiency to the standard one increases as exp{m_0t/2}, where m_0 is\nthe mass gap and t the time separation."
    },
    {
        "anchor": "Two-neutrino double-beta decay in pionless effective field theory from a\n  Euclidean finite-volume correlation function: Two-neutrino double-beta decay of certain nuclear isotopes is one of the\nrarest Standard Model processes observed in nature. Its neutrinoless\ncounterpart is an exotic lepton-number nonconserving process that is widely\nsearched for to determine if the neutrinos are Majorana fermions. In order to\nconnect the rate of these processes to the Standard Model and beyond the\nStandard Model interactions, it is essential that the corresponding nuclear\nmatrix elements are constrained reliably from theory. Lattice quantum\nchromodynamics (LQCD) and low-energy effective field theories (EFTs) are\nexpected to play an essential role in constraining the matrix element of the\ntwo-nucleon subprocess, which could in turn provide the input into ab initio\nnuclear-structure calculations in larger isotopes. Focusing on the two-neutrino\nprocess $nn \\to pp \\, (ee \\bar{\\nu}_e\\bar{\\nu}_e)$, the amplitude is\nconstructed in this work in pionless EFT at next-to-leading order,\ndemonstrating the emergence of a renormalization-scale independent amplitude\nand the absence of any new low-energy constant at this order beyond those\npresent in the single-weak process. Most importantly, it is shown how a LQCD\nfour-point correlation function in Euclidean and finite-volume spacetime can be\nused to constrain the Minkowski infinite-volume amplitude in the EFT. The same\nformalism is provided for the related single-weak process, which is an input to\nthe double-$\\beta$ decay formalism. The LQCD-EFT matching procedure outlined\nfor the double-weak amplitude paves the road toward constraining the\ntwo-nucleon matrix element entering the neutrinoless double-beta decay\namplitude with a light Majorana neutrino.",
        "positive": "The scalar, vector and tensor form factors for the pion and kaon from\n  lattice QCD: We present a calculation of the scalar, vector, and tensor form factors for\nthe pion and kaon in lattice QCD. We use an ensemble of two degenerate light, a\nstrange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with\nclover improvement. The corresponding pion and kaon masses are about 265 MeV\nand 530 MeV, respectively. The calculation is done in both rest and boosted\nframes obtaining data for four-vector momentum transfer squared up to\n$-q^2=2.5$ GeV$^2$ for the pion and 3 GeV$^2$ for the kaon. The excited-states\neffects are studied by analyzing six values of the source-sink time separation\nfor the rest frame ($1.12-2.23$ fm) and for four values for the boosted frame\n($1.12-1.67$ fm). The lattice data are renormalized non-perturbatively and the\nresults for the scheme- and scale-dependent scalar and tensor form factors are\npresented in the $\\overline{\\rm MS}$ scheme at a scale of 2 GeV. We apply\ndifferent parametrizations to describe $q^2$-dependence of the form factors to\nextract the scalar, vector, and tensor radii, as well as the tensor anomalous\nmagnetic moment. We compare the pion and kaon form factors to study SU(3)\nflavor symmetry breaking effects. By combining the data for the vector and\ntensor form factors we also obtain the lowest moment of the densities of\ntransversely polarized quarks in the impact parameter space. Finally, we give\nan estimate for the average transverse shift in the $y$ direction for polarized\nquarks in the $x$ direction."
    },
    {
        "anchor": "Search for the Charmonium Dissociation Temperature with Variational\n  Analysis in Lattice QCD: Charmonium dissociation temperatures are studied in a quenched anisotropic\nlattice QCD with standard plaquette gauge action and O(a) improved Wilson\nfermion action. Simulations are carried out at temperatures in the range\n0.88T_c to 2.3T_c. From the meson correlators, we first subtract the\ncontribution of constant mode, which was reported to mislead the analysis of,\nin particular, P wave signals. We then calculate effective masses and\nBethe-Salpeter wave functions for ground (1S, 1P) and excited states (2S, 2P)\nusing the multi-state variational analysis. To distinguish between bound states\nand scattering states, we apply two methods: First, we compare effective masses\nfor charmonium correlation functions with finite spatial momenta under\ndifferent spatial boundary conditions. Since the scattering state energies are\nsensitive to the boundary conditions, we expect finite volume effects when the\ncharmonium dissociates. Second, we study the Bethe-Salpeter wave function,\nwhich should become broad when the charmonium bound state turns into a\nscattering state. With both methods, we have fond no clear evidences of\ndissociation for the ground and exited charmonium states up to 2.3T_c so far.",
        "positive": "Parton Distribution Functions from Ioffe Time Pseudodistributions from\n  Lattice Calculations: Approaching the Physical Point: We present results for the unpolarized parton distribution function of the\nnucleon computed in lattice QCD at the physical pion mass. This is the first\nstudy of its kind employing the method of Ioffe time pseudo-distributions.\nBeyond the reconstruction of the Bjorken-$x$ dependence we also extract the\nlowest moments of the distribution function using the small Ioffe time\nexpansion of the Ioffe time pseudo-distribution. We compare our findings with\nthe pertinent phenomenological determinations."
    },
    {
        "anchor": "Discretization errors in the spectrum of the Hermitian Wilson-Dirac\n  operator: I study the leading effects of discretization errors on the low energy part\nof the spectrum of the Hermitian Wilson-Dirac operator in infinite volume. The\nmethod generalizes that used to study the spectrum of the Dirac operator in the\ncontinuum, and uses partially quenched chiral perturbation theory for Wilson\nfermions. The leading-order corrections are proportional to a^2 (a being the\nlattice spacing). At this order I find that the method works only for one\nchoice of sign of one of the three low energy constants describing\ndiscretization errors. If these constants have the relative magnitudes expected\nfrom large N_c arguments, then the method works if the theory has an Aoki phase\nfor m of order a^2, but fails if there is a first-order transition. In the\nformer case, the dependence of the gap and the spectral density on m and a^2\nare determined. In particular, the gap is found to vanish more quickly as\nm_pi^2-> 0 than in the continuum. This reduces the region where simulations are\nsafe from fluctuations in the gap.",
        "positive": "Insight into thermal modifications of quarkonia from a comparison of\n  continuum-extrapolated lattice results to perturbative QCD$^{\\dagger}$: In this work, we strive to gain insight into thermal modifications of\ncharmonium and bottomonium bound states as well as the heavy quark diffusion\ncoefficient. The desired information is contained in the spectral function\nwhich can not be calculated on the lattice directly. Instead, the correlator\ngiven by an integration over the spectral function times an integration kernel\nis obtained. Extracting the spectral function is an ill-posed inversion problem\nand various different solutions have been proposed. We focus on a comparison to\na spectral function obtained from combining perturbative and pNRQCD\ncalculations. In order to get precise results, continuum extrapolated\ncorrelators originating from large and fine lattices are used. We first analyze\nthe pseudoscalar channel since the absence of a transport peak simplifies the\nanalysis. The knowledge gained from this is then used to extend the analysis to\nthe vector channel, where information on heavy quark transport is encoded in\nthe low frequency regime of the spectral function. The comparison shows a\nqualitatively good agreement between perturbative and lattice correlators.\nQuantitative differences can be explained by systematic uncertainties."
    },
    {
        "anchor": "Strategies for the Determination of the Running Coupling of\n  $(2+1)$-dimensional QED with Quantum Computing: We propose to utilize NISQ-era quantum devices to compute short distance\nquantities in $(2+1)$-dimensional QED and to combine them with large volume\nMonte Carlo simulations and perturbation theory. On the quantum computing side,\nwe perform a calculation of the mass gap in the small and intermediate regime,\ndemonstrating, in the latter case, that it can be resolved reliably. The so\nobtained mass gap can be used to match corresponding results from Monte Carlo\nsimulations, which can be used eventually to set the physical scale. In this\npaper we provide the setup for the quantum computation and show results for the\nmass gap and the plaquette expectation value. In addition, we discuss some\nideas that can be applied to the computation of the running coupling. Since the\ntheory is asymptotically free, it would serve as a training ground for future\nstudies of QCD in $(3+1)$-dimensions on quantum computers.",
        "positive": "Scaling and Further Tests of Heavy Meson Decay Constant Determinations\n  from Nonrelativistic QCD: We present results for the B_s meson decay constant f_{B_s} from simulations\nat three lattice spacings in the range a^{-1}=1.1 to 2.6 GeV using NRQCD heavy\nquarks and clover light quarks in the quenched approximation. We study scaling\nof this quantity and check the consistency between mesons decaying from rest\nand from a state with nonzero spatial momentum. The cancellation of power law\ncontributions that arise in the NRQCD formulation of heavy-light currents is\ndiscussed. On the coarsest lattice the D_s meson decay constant f_{D_s} is\ncalculated. Our best values for the decay constants are given by f_{B_s} =\n187(4)(4)(11)(2)(7)(6) MeV and f_{D_s} = 223(6)(31)(38)(23)(9)(^{+3}_{-1}) MeV."
    },
    {
        "anchor": "Neutron Electric Dipole Moment on the Lattice: For the neutron to have an electric dipole moment (EDM), the theory of nature\nmust have T, or equivalently CP, violation. Neutron EDM is a very good probe of\nnovel CP violation in beyond the standard model physics. To leverage the\nconnection between measured neutron EDM and novel mechanism of CP violation,\none requires the calculation of matrix elements for CP violating operators, for\nwhich lattice QCD provides a first principle method. In this paper, we review\nthe status of recent lattice QCD calculations of the contributions of the QCD\n$\\Theta$-term, the quark EDM term, and the quark chromo-EDM term to the neutron\nEDM.",
        "positive": "Virtual Photon Emission in Leptonic Decays of Charged Pseudoscalar\n  Mesons: We study the radiative leptonic decays\n$P\\to\\ell\\nu_\\ell\\,\\ell^{\\prime\\,+}\\ell^{\\prime\\,-}$, where $P$ is a\npseudoscalar meson and $\\ell$ and $\\ell^\\prime$ are charged leptons. In such\ndecays the emitted photon is off-shell and, in addition to the \"point-like\"\ncontribution in which the virtual photon is emitted either from the lepton or\nthe meson treated as a point-like particle, four structure-dependent (SD) form\nfactors contribute to the amplitude. We present a strategy for the extraction\nof the SD form factors and implement it in an exploratory lattice computation\nof the decay rates for the four channels of kaon decays\n($\\ell,\\ell^\\prime=e,\\mu$). It is the SD form factors which describe the\ninteraction between the virtual photon and the internal hadronic structure of\nthe decaying meson, and in our procedure we separate the SD and point-like\ncontributions to the amplitudes. We demonstrate that the form factors can be\nextracted with good precision and, in spite of the unphysical quark masses used\nin our simulation ($m_\\pi\\simeq 320\\,$MeV and $m_K\\simeq 530\\,$MeV), the\nresults for the decay rates are in reasonable semiquantitative agreement with\nexperimental data (for the channels where these exist). Following this\npreparatory work, the emphasis of our future work will be on obtaining results\nat physical quark masses and on the control of the systematic uncertainties\nassociated with discretisation and finite-volume errors."
    },
    {
        "anchor": "Distribution of Canonical Determinants in QCD: The distribution of canonical determinants in QCD is determined by means of\nchiral perturbation theory. For a non-zero quark charge the canonical\ndeterminants take complex values. In the dilute pion gas approximation, we\ncompute all moments of the magnitude of the canonical determinants, as well as\nthe first nonvanishing moments of the real and imaginary parts. The non-trivial\ncancellation between the real and the imaginary parts of the canonical\ndeterminants is derived and the signal to noise ratio is discussed. The\nanalytical distributions are compared to lattice data. The average density of\nthe magnitude of the canonical determinants is determined as well and is shown\nto be given by a variant of the log-normal distribution.",
        "positive": "Beyond the Standard Model B-parameters with improved staggered fermions\n  in $N_f=2+1$ QCD: We calculate the kaon mixing B-parameters for operators arising generically\nin theories of physics beyond the standard model. We use HYP-smeared improved\nstaggered fermions on the $N_f = 2+1$ MILC asqtad lattices. Operator matching\nis done perturbatively at one-loop order. Chiral extrapolations are done using\n\"golden combinations\" in which one-loop chiral logarithms are absent. For the\ncombined sea-quark mass and continuum extrapolation, we use three lattice\nspacings: $a \\approx 0.045, 0.06$ and $0.09 \\text{fm}$. Our results have a\ntotal error of 5-6%, which is dominated by the systematic error from matching\nand continuum extrapolation. For two of the BSM $B$-parameters, we agree with\nresults obtained using domain-wall and twisted-mass dynamical fermions, but we\ndisagree by $(4-5)\\sigma$ for the other two."
    },
    {
        "anchor": "Improved Pseudofermion Approach for All-Point Propagators: Quark propagators with arbitrary sources and sinks can be obtained more\nefficiently using a pseudofermion method with a mode-shifted action.\nMode-shifting solves the problem of critical slowing down (for light quarks)\ninduced by low eigenmodes of the Dirac operator. The method allows the full\nphysical content of every gauge configuration to be extracted, and should be\nespecially helpful for unquenched QCD calculations. The method can be applied\nfor all the conventional quark actions: Wilson, Sheikoleslami-Wohlert,\nKogut-Susskind, as well as Ginsparg-Wilson compliant overlap actions. The\nstatistical properties of the method are examined and examples of physical\nprocesses under study are presented.",
        "positive": "Deconfined SU(2) vector fields at zero temperature: Markov chain Monte Carlo simulations of pure SU(2)xU(1) lattice gauge theory\nshow a (zero temperature) deconfining phase transition in the SU(2) gluon\nsector when a term is added to the SU(2) and U(1) Wilson actions, which\nrequires joint U(2) gauge transformations of the SU(2) and U(1) vector fields.\nInvestigations of this deconfined phase are of interest as it could provide an\nalternative to the Higgs mechanism."
    },
    {
        "anchor": "Taste symmetry violation at finite temperature: Symmetries play a distinctive role at the high temperature phase transition\nin QCD. Therefore the spectrum of screening masses has been investigated with\nemphasis on taste breaking. Although taste violation is an UV effect the\nrelevant operators could be temperature dependent. We have studied the meson\nscreening masses in the temperature range between 140 MeV to 550 MeV. The\ncomputation has been performed using dynamical N_f = 2+1 gauge field\nconfigurations generated with the p4 staggered action. For temperatures below\nthe transition an agreement with the prediction of staggered chiral\nperturbation theory has been found and no temperature effect can be observed on\nthe taste violation. Above the transition the taste splitting still shows an\nO(a^2) behavior but with a temperature dependent slope.",
        "positive": "Heavy quark expansion parameters from lattice NRQCD: Using the lattice NRQCD action for heavy quark, we calculate the heavy quark\nexpansion parameters $\\mu_{\\pi}^2$ and $\\mu_G^2$ for heavy-light mesons and\nheavy-light-light baryons. The results are compared with the mass differences\namong heavy hadrons to test the validity of HQET relations on the lattice."
    },
    {
        "anchor": "Light-meson leptonic decay rates in lattice QCD+QED: The leading electromagnetic (e.m.) and strong isospin-breaking corrections to\nthe $\\pi^+ \\to \\mu^+ \\nu[\\gamma]$ and $K^+ \\to \\mu^+ \\nu[\\gamma]$ leptonic\ndecay rates are evaluated for the first time on the lattice. The results are\nobtained using gauge ensembles produced by the European Twisted Mass\nCollaboration with $N_f = 2 + 1 + 1$ dynamical quarks. The relative\nleading-order e.m.~and strong isospin-breaking corrections to the decay rates\nare 1.53(19)\\% for $\\pi_{\\mu 2}$ decays and 0.24(10)\\% for $K_{\\mu 2}$ decays.\nUsing the experimental values of the $\\pi_{\\mu 2}$ and $K_{\\mu 2}$ decay rates\nand updated lattice QCD results for the pion and kaon decay constants in\nisosymmetric QCD, we find that the Cabibbo-Kobayashi-Maskawa matrix element $ |\nV_{us}| = 0.22538(46)$, reducing by a factor of about $1.8$ the corresponding\nuncertainty in the Particle Data Group review. Our calculation of $|V_{us}|$\nallows also an accurate determination of the first-row CKM unitarity relation\n$| V_{ud}|^2 + | V_{us}|^2 + | V_{ub}|^2 = 0.99988(46)$. Theoretical\ndevelopments in this paper include a detailed discussion of how QCD can be\ndefined in the full QCD+QED theory and an improved renormalisation procedure in\nwhich the bare lattice operators are renormalised non-perturbatively into the\n(modified) Regularization Independent Momentum subtraction scheme and\nsubsequently matched perturbatively at $O(\\alpha_{em}\\alpha_s(M_W))$ into the\nW-regularisation scheme appropriate for these calculations.",
        "positive": "On the gauge-algebra dependence of Landau-gauge Yang-Mills propagators: Yang-Mills theory can be formulated for any semi-simple Lie algebra, and thus\nany semi-simple Lie group. In principle, the dynamics could be different for\neach one. However, functional studies predict that the propagators in Landau\ngauge depend only quantitatively on the gauge algebra. In particular, genuine\nnon-perturbative effects should be present even in the large N-limit for su(N)\ngauge algebras.\n  Lattice gauge theory is used to investigate this in detail. The propagators\nare determined for the gauge groups SU(2), SU(3), SU(4), SU(5), SU(6) and G2,\nin two and three dimensions. In accordance with the prediction no qualitative\ndependence on the gauge group is found. In particular, no diminishing of\nnon-perturbative contributions is found for N becoming large in the SU(N) case.\nQuantitative effects are found, and analyzed in detail."
    },
    {
        "anchor": "Tensor renormalization group approach to four-dimensional complex\n  $\u03c6^4$ theory at finite density: Tensor network is an attractive approach to field theory with negative sign\nproblem. The complex $\\phi^4$ theory at finite density is a test bed for\nnumerical algorithms to verify their effectiveness. The model shows a\ncharacteristic feature called the Silver Blaze phenomenon associated with the\nsign problem in the large volume limit at low temperature. We analyze the\nfour-dimensional model employing the anisotropic tensor renormalization group\nalgorithm. We find a clear signal of the Silver Blaze phenomenon on a large\nvolume of $V=1024^4$, which implies that the tensor network approach is\neffective even for four-dimensional field theory beyond two dimensions.",
        "positive": "Topological aspects of QCD: We review recent results from lattice on topological aspects of QCD: most of\nthe results refer to monopoles and to instantons. We discuss in detail the\nevidence for condensation of monopoles in the vacuum and confinement of colour\nby dual superconductivity, and the major role of monopoles in dynamics\n(monopole dominance). As for instantons we review the $U(1)$ problem, a\npossible determination of the spin content of the proton, and new lattice data\nrelevant to instanton liquid models."
    },
    {
        "anchor": "Numerical Study of Dense Adjoint Matter in Two Color QCD: We identify the global symmetries of SU(2) lattice gauge theory with N\nflavors of staggered fermion in the presence of a quark chemical potential mu,\nfor fermions in both fundamental and adjoint representations, and anticipate\nlikely patterns of symmetry breaking at both low and high densities. Results\nfrom numerical simulations of the model with N=1 adjoint flavor on a 4^3x8\nlattice are presented, using both hybrid Monte Carlo and Two-Step Multi-Boson\nalgorithms. It is shown that the sign of the fermion determinant starts to\nfluctuate once the model enters a phase with non-zero baryon charge density.\nHMC simulations are not ergodic in this regime, but TSMB simulations retain\nergodicity even in the dense phase, and in addition appear to show superior\ndecorrelation. The HMC results for the equation of state and the pion mass show\ngood quantitative agreement with the predictions of chiral perturbation theory,\nwhich should hold only for N>=2. The TSMB results incorporating the sign of the\ndeterminant support a delayed onset transition, consistent with the pattern of\nsymmetry breaking expected for N=1.",
        "positive": "A Convergence Proof for Linked Cluster Expansions: We prove that for a general $N$-component model on a $d$-dimensional lattice\n$\\bZ^d$ with pairwise nearest-neighbor coupling and general local interaction\nobeying a stability bound the linked cluster expansion has a finite radius of\nconvergence. The proof uses Mayer Montroll equations for connected Green\nfunctions."
    },
    {
        "anchor": "Continuum limit of two-dimensional multiflavor scalar gauge theories: We address the interplay between local and global symmetries by analyzing the\ncontinuum limit of two-dimensional multicomponent scalar lattice gauge\ntheories, endowed by non-Abelian local and global invariance. These theories\nare asymptotically free. By exploiting Monte Carlo simulations and finite-size\nscaling techniques, we provide numerical results concerning the universal\nbehavior of such models in the critical regime. Our results support the\nconjecture that two-dimensional multiflavor scalar models have the same\ncontinuum limit as the $\\sigma$-models associated with symmetric spaces that\nhave the same global symmetry.",
        "positive": "The flux distribution of the three quark system in SU(3): We study the abelian color-flux distribution of the three quark system in the\nmaximally abelian gauge on SU(3) lattices. The distribution of the color\nelectric field suggests $Y Ansatz$, which might be interpreted through the dual\nsuperconductor picture as the result of the vacuum pressure in the confined\nphase. In order to clarify the flux structure, we investigate the color\nelectric field in the three quark system also in the monopole part and in the\nphoton part."
    },
    {
        "anchor": "Thermal QCD phase transition with dynamical chiral fermions: We discuss properties of Quantum Chromodynamics at finite temperature\nobtained by means of lattice simulations with overlap fermions. This fermion\ndiscretization preserves chiral symmetry even at finite lattice spacing. We\npresent details of the lattice formulation, first results for the chiral\nobservables and discuss the behaviour of the system near the chiral thermal\nphase transition.",
        "positive": "Evidence for Asymptotic Safety from Lattice Quantum Gravity: We calculate the spectral dimension for nonperturbative quantum gravity\ndefined via Euclidean dynamical triangulations. We find that it runs from a\nvalue of ~3/2 at short distance to ~4 at large distance scales, similar to\nresults from causal dynamical triangulations. We argue that the short distance\nvalue of 3/2 for the spectral dimension may resolve the tension between\nasymptotic safety and the holographic principle."
    },
    {
        "anchor": "Sea Contributions to Hadron Electric Polarizabilities through\n  Reweighting: As part of our ongoing lattice study of the electric polarizabilities of\nhadrons using the background field approach, we use reweighting to examine the\neffect of the field on the sea quarks. As with other reweighting studies, the\nchief difficulty lies in the construction of a stochastic estimate of the ratio\nof the fermion determinants. In contrast to the case of reweighting in the\nquark mass, these estimators converge extremely slowly, and are resistant to\ncommon variance-reduction techniques such as low-mode subtraction. However, it\nis possible to construct an alternate estimator, taking advantage of the fact\nthat we are interested in only perturbatively small fields; this estimator is\nsusceptible to a variance-reduction technique based on a hopping parameter\nexpansion.",
        "positive": "From Quarks to Nuclei: Challenges of Lattice QCD: I discuss challenge of lattice QCD, from quarks to nuclei, which connects QCD\nwith nuclear physics."
    },
    {
        "anchor": "High-energy hadron-hadron (dipole-dipole) scattering from lattice QCD: In this paper the problem of high-energy hadron-hadron (dipole-dipole)\nscattering is approached (for the first time) from the point of view of lattice\nQCD, by means of Monte Carlo numerical simulations. In the first part, we give\na brief review of how high-energy scattering amplitudes can be reconstructed,\nusing a functional-integral approach, in terms of certain correlation functions\nof two Wilson loops and we also briefly recall some relevant analyticity and\ncrossing-symmetry properties of these loop-loop correlation functions, when\ngoing from Euclidean to Minkowskian theory. In the second part, we shall see\nhow these (Euclidean) loop-loop correlation functions can be evaluated in\nlattice QCD and we shall compare our numerical results with some\nnonperturbative analytical estimates that appeared in the literature,\ndiscussing in particular the question of the analytic continuation from\nEuclidean to Minkowskian theory and its relation to the still unsolved problem\nof the asymptotic s-dependence of the hadron-hadron total cross sections.",
        "positive": "Continuous space-time symmetries in a lattice field theory: For purposes of regularization as well as numerical simulation, the\ndiscretization of Lorentz invariant continuum field theories on a space-time\nlattice is often convenient. In general, this discretization destroys the\nrotational or Lorentz-frame independence of the theory, which is only recovered\nin the continuum limit. The Baxter 8-vertex model may be interpreted as a\nparticular discretization of a self-interacting massive Dirac fermion theory in\ntwo dimensions (the massive Thirring model). Here it is shown that, in the\n8-vertex/massive Thirring model, the Lorentz frame independence of the theory\nremains undisturbed on the lattice. The only effect of the discretization is to\ncompactify the manifold of Lorentz frames. The relationship between this\nlattice Lorentz symmetry and the Yang-Baxter relations is discussed."
    },
    {
        "anchor": "Phase-diagram of two-color lattice QCD in the chiral limit: We study thermodynamics of strongly coupled lattice QCD with two colors of\nmassless staggered fermions as a function of the baryon chemical potential\n$\\mu$ in 3+1 dimensions using a new cluster algorithm. We find evidence that\nthe model undergoes a weak first order phase transition at $\\mu=0$ which\nbecomes second order at a finite $\\mu$. Symmetry considerations suggest that\nthe universality class of these phase transitions should be governed by an\n$O(N)\\times O(2)$ field theory with collinear order, with N=3 at $\\mu=0$ and\nN=2 at $\\mu \\neq 0$. The universality class of the second order phase\ntransition at $\\mu\\neq 0$ appears to be governed by the decoupled XY fixed\npoint present in the $O(2)\\times O(2)$ field theory. Finally we show that the\nquantum (T=0) phase transition as a function of $\\mu$ is a second order mean\nfield transition.",
        "positive": "Conserved charge fluctuations in the chiral limit: We study the signs of criticality in conserved charge fluctuations and\nrelated observables of finite temperature QCD at vanishing chemical potential,\nas we approach the chiral limit of two light quarks. Our calculations have been\nperformed on gauge ensembles generated using Highly Improved Staggered Quark\n(HISQ) fermion action, with pion masses ranging from 140 MeV to 55 MeV."
    },
    {
        "anchor": "Topological susceptibility in two-flavor lattice QCD with exact chiral\n  symmetry: We determine the topological susceptibility $\\chi_t$ in two-flavor QCD using\nthe lattice simulations at a fixed topological sector. The topological charge\ndensity is unambiguously defined on the lattice using the overlap-Dirac\noperator which possesses exact chiral symmetry. Simulations are performed on a\n$16^3 \\times 32$ lattice at lattice spacing $\\sim$ 0.12 fm at six sea quark\nmasses $m_q$ ranging in $m_s/6$--$m_s$ with $m_s$ the physical strange quark\nmass. The $\\chi_t$ is extracted from the constant behavior of the\ntime-correlation of flavor-singlet pseudo-scalar meson two-point function at\nlarge distances, which arises from the finite size effect due to the fixed\ntopology. In the small $m_q$ regime, our result of $\\chi_t$ is proportional to\n$m_q$ as expected from chiral effective theory. Using the formula\n$\\chi_t=m_q\\Sigma/N_f$ by Leutwyler-Smilga, we obtain the chiral condensate in\n$N_f=2$ QCD as $\\Sigma^{\\bar{\\mathrm{MS}}}(\\mathrm{2 GeV}) = [252(5)(10)\n\\mathrm{MeV}]^3 $, in good agreement with our previous result obtained in the\n$\\epsilon$-regime.",
        "positive": "Dual Abrikosov Vortices in Confining Theories: The spacial distribution of fields and currents in confining theories can\ngive direct evidence of dual superconductivity. We would like to discuss the\ntechniques for finding these properties and calculating the superconductivity\nparameters in lattice simulations. We have seen dual Abrikosov vortices\ndirectly in pure U(1) and SU(2) and others have also seen them in SU(3). In the\nnon-Abelian cases the system appears to be near the borderline between type I\nand II. We also discuss the response of the supercurrents to external fields."
    },
    {
        "anchor": "Distribution of Instanton and Monopole Clustering: We study the relation between the instanton distribution and the monopole\nloop length in the SU(2) gauge theory with the abelian gauge fixing. We measure\nthe monopole current from the multi-instanton ensemble on the $16^4$ lattice\nusing the maximally abelian gauge. When the instanton density is dilute, there\nappear only small monopole loops. On the other hand, in the dense case, there\nappears one very long monopole loop, which is responsible for the confinement\nproperty, in each gauge configuration. We find a clear monopole clustering in\nthe histogram of the monopole loop length from 240 gauge configurations.",
        "positive": "QCD thermodynamics at non-zero isospin asymmetry: We study the thermodynamic properties of QCD at nonzero isospin chemical\npotential using improved staggered quarks at physical quark masses. In\nparticular, we discuss the determination of the equation of state at zero and\nnonzero temperatures and show results. Using the results for the isospin\ndensity $n_I$, we also determine the phase diagram in the $(n_I,T)$-plane."
    },
    {
        "anchor": "Surface modes and chiral symmetry (Wilson Fermions in a box): We give a Hamiltonian discussion of surface states in an extra dimension as a\nbasis for chiral fermions in lattice models. Such modes appear with the Wilson\nfermion action when the hopping parameter exceeds a critical value. The\nassociation of such states with the closing and reopening of a band gap was\nnoted by Shockley in 1939. Poster presented by Michael Creutz at Lattice 93.\nUuencoded compressed postscript file.",
        "positive": "Symmetries and spectrum of SU(2) Lattice Gauge Theory at finite chemical\n  potential: We study SU(2) Lattice Gauge Theory with dynamical fermions at non-zero\nchemical potential $\\mu$. The symmetries special to SU(2) for staggered\nfermions on the lattice are discussed explicitly and their relevance to\nspectroscopy and condensates at non-zero chemical potential are considered.\nUsing the molecular dynamics algorithm on small lattices we find qualitative\nchanges in the theory's spectroscopy at small and large values of $\\mu$. This\npreliminary study should lay the groundwork for future large scale simulations."
    },
    {
        "anchor": "Charmonium spectra and dispersion relation with improved Bayesian\n  analysis in lattice QCD: We study the charmonium spectral functions at finite momentum and the\ndispersion relation of $\\eta_c$ at finite temperature. For the analysis of the\nspectral function, we use an extended maximum entropy method (MEM). We perform\nthe MEM analysis for the product space of Euclidean correlators in different\nchannels or momenta to incorporate information encoded in correlations among\nthe Euclidean correlators in MEM. We find that this method can improve the\nerror of the reconstructed spectral images. To study the dispersion relation,\nwe introduce a definition of the peak position in the spectral image in which\nthe associated error can be estimated on the basis of MEM. We find that the\ndispersion relation of $\\eta_c$ at finite temperature follows the Lorentz\ninvariant form even near the dissociation temperature $T\\simeq1.7T_c$.",
        "positive": "A Lattice Chiral Theory with Multifermion Couplings: Analyzing an $SU_L(2)\\otimes U_R(1)$ chiral theory with multifermion\ncouplings on a lattice, we find a possible region in the phase space of\nmultifermion couplings, where no spontaneous symmetry breaking occurs, doublers\nare decoupled as massive Dirac fermions consistently with the $SU_L(2)\\otimes\nU_R(1)$ chiral symmetry, the ``spectator'' fermion $\\psi_R(x)$ is free mode,\nwhereas the normal mode of $\\psi^i_L(x)$ is plausibly speculated to be chiral\nin the continuum limit. This is not in agreement with the general belief of the\ndefinite failure of theories so constructed."
    },
    {
        "anchor": "Nucleon and Nucleon to Delta Axial form factors from Lattice QCD: We present results on the nucleon axial vector form factors $G_A(q^2)$ and\n$G_p(q^2)$ in the quenched theory and using two degenerate flavors of dynamical\nWilson fermions for momentum transfer squared from about 0.1 to about 2 GeV^2\nand for pion masses in the range of 380 to 600 MeV. We also present results on\nthe corresponding N to Delta axial vector transition form factors $C_5^A(q^2)$\nand $C_6^A(q^2)$ using, in addition to Wilson fermions, domain wall valence\nquarks and dynamical staggered sea quarks provided by the MILC collaboration.",
        "positive": "Weak transition matrix elements from finite-volume correlation functions: The two-body decay rate of a weakly decaying particle (such as the kaon) is\nshown to be proportional to the square of a well-defined transition matrix\nelement in finite volume. Contrary to the physical amplitude, the latter can be\nextracted from finite-volume correlation functions in euclidean space without\nanalytic continuation. The K -> pi pi transitions and other non-leptonic decays\nthus become accessible to established numerical techniques in lattice QCD."
    },
    {
        "anchor": "Study of 1/m corrections in HQET: We report our exploratory study on the matching condition of HQET with QCD\nincluding 1/m corrections. We introduce a new observable from the dependence of\nthe heavy-light effective energy on the twisted boundary condition parameter\n$\\theta$, which could be used to match the kinetic term $\\vec{D}^2/(2m)$.\nCarrying out quenched QCD simulations for fixed lattice spacing in small\nvolumes with O(a)-improved Wilson fermions, we study the 1/m dependence of this\nobservable, from which the static limit and 1/m coefficient can be extracted.\nWe also compare our preliminary result with HQET.",
        "positive": "Bottom and Charm quark masses from lattice NRQCD: We present new values for the $\\bar{MS}$ masses of $b$ and $c$ quarks based\non lattice NRQCD simulations of the $\\Upsilon (b\\bar{b})$ and $\\psi (c\\bar{c})$\nsystems. These include three measurements of the $b$ mass based on quenched\nsimulations with lattice spacings ranging from 0.05fm to 0.15fm, which we find\nto be largely independent of lattice spacing. In addition, we find a consistent\nvalue from an unquenched simulation at 0.08fm."
    },
    {
        "anchor": "Two-flavor lattice QCD study of $\u039b$(1405): Low-lying $\\Lambda$ baryons with spin 1/2 are analyzed in two-flavor\nunquenched lattice QCD. We construct $2 \\times 2$ cross correlators from flavor\nSU(3) ``octet'' and ``singlet'' baryon operators, and diagonalize them so that\nwe can extract two low-lying states for each parity. The two-flavor CP-PACS\ngauge configurations are employed, which are generated in the\nrenormalization-group improved gauge action and the ${\\mathcal O}(a)$-improved\nquark action. Simulation are performed at three different $\\beta$'s, $\\beta =\n1.80$, 1.95 and 2.10, whose corresponding lattice spacings are $a = 0.2150$,\n0.1555 and 0.1076 fm. For each cutoff, we adopt four different hopping\nparameters, ($\\kappa_{\\rm val}, \\kappa_{\\rm sea}$). The corresponding pion\nmasses range about from 500 MeV to 1.1 GeV. Results indicate that there are two\nnegative-parity $\\Lambda$ states nearly degenerate at around 1.6 GeV, while no\nstate as low as $\\Lambda (1405)$ is observed. By decomposing the flavor\ncomponents of each state, we find that the lowest (1st-excited) negative-parity\nstate is dominated by flavor-singlet (flavor-octet) component.",
        "positive": "Analytic and numerical study of the free energy in gauge theory: We derive some exact bounds on the free energy W(J) in an SU(N) gauge theory,\nwhere J_mu^b is a source for the gluon field A_mu^b in the minimal Landau\ngauge, and W(J) is the generating functional of connected correlators, exp W(J)\n= <exp(J, A)>. We also provide asymptotic expressions for the free energy W(J)\nat large J and for the quantum effective action Gamma(A) at large A. We\nspecialize to a source J(x)=h cos(kx) of definite momentum k and source\nstrength h, and study the gluon propagator D(k,h) in the presence of this\nsource. Among other relations, we prove int_0^inf dh D(k,h)<=2^1/2 k, which\nimplies lim_(k->0) D(k,h) = 0, for all positive h>0. Thus the system does not\nrespond to a static color probe, no matter how strong. Recent lattice data in\nminimal Landau gauge in d =3 and 4 dimensions at h=0 indicate that the gluon\npropagator in the minimum Landau gauge is finite, lim_(k->0) D(k,0)>0. Thus\nthese lattice data imply a jump in the value of D(k,h) at h=0 and k=0, and the\nvalue of D(k,h) at this point depends on the order of limits. We also present\nnumerical evaluations of the free energy W(k,h) and the gluon propagator D(k,h)\nfor the case of SU(2) Yang-Mills theory in various dimensions which support all\nof these findings."
    },
    {
        "anchor": "The Heavy Quark Masses from Quarkonia: We report on the status of the determination of the heavy quark masses from\nour calculation of the quarkonia spectra. All sources of systematic errors that\nenter the quark mass determination are accounted for. We explicitly keep $ma\n\\neq 0$ in the perturbative calculation relating the bare lattice mass to a\nrenormalized mass. Our results are still preliminary.",
        "positive": "Exploring the Phase Diagram with Taylor Series: Epic Voyage or Just\n  Another Bad Trip: It has been suggested in the literature that it may be possible to locate the\nQCD critical end point using the Taylor series of thermodynamic variables about\nthe $\\mu=0$ axis. Since the phase transition at the critical end point is\nbelieved to be in the 3D Ising universality class, it would seem natural to\ntest this method with the Ising Model, for which the answer is already known.\nThe finding is that it is in fact possible to pinpoint the location of the\nIsing critical point using Taylor coefficients."
    },
    {
        "anchor": "Random matrix model for QCD_3 staggered fermions: We show that the lowest part of the eigenvalue density of the staggered\nfermion operator in lattice QCD_3 at small lattice coupling constant beta has\nexactly the same shape as in QCD_4. This observation is quite surprising, since\nuniversal properties of the QCD_3 Dirac operator are expected to be described\nby a non-chiral matrix model. We show that this effect is related to the\nspecific nature of the staggered fermion discretization and that the eigenvalue\ndensity evolves towards the non-chiral random matrix prediction when beta is\nincreased and the continuum limit is approached. We propose a two-matrix model\nwith one free parameter which interpolates between the two limits and very well\nmimics the pattern of evolution with beta of the eigenvalue density of the\nstaggered fermion operator in QCD_3.",
        "positive": "The Pion Form Factor at Large Momentum Transfer: We present our calculations of the electromagnetic form factor of pions. We\nexplore the properties of pion form factor at momentum transfer larger than\nprevious studies by including more combinations of source and sink momenta and\nusing more configurations.We fit our results using vector meson dominance (VMD)\nhypothesis."
    },
    {
        "anchor": "Effects of boundary conditions and gradient flow in 1+1 dimensional\n  lattice $\u03c6^4$ theory: In this work we study the effects of gradient flow and open boundary\ncondition in the temporal direction in 1+1 dimensional lattice $\\phi^4$ theory.\nSimulations are performed with periodic (PBC) and open (OPEN) boundary\nconditions in the temporal direction. The Effects of gradient flow and open\nboundary on the field $\\phi$ and the susceptibility are studied in detail along\nwith the finite size scaling analysis. In both cases, at a given volume, the\nphase transition point is shifted towards a lower value of lattice coupling\n$\\lambda_0$ for fixed $m_0^2$ in the case of OPEN as compared to PBC with this\nshift found to be diminishing as volume increases. We compare and contrast the\nextraction of the boson mass from the two point function (PBC) and the one\npoint function (OPEN) as the coupling, starting from moderate values,\napproaches the critical value corresponding to the vanishing of the mass gap.\nIn the critical region, boundary artifacts become dominant in the latter. Our\nstudies point towards the need for a detailed finite volume (scaling) analysis\nof the effects of OPEN in the critical region.",
        "positive": "Magnetic translation symmetry on the lattice: Magnetic translation symmetry on a finite periodic square lattice is\ninvestigated for an arbitrary uniform magnetic field in arbitrary dimensions.\nIt can be used to classify eigenvectors of the Hamiltonian. The system can be\nconverted to another system of half or lower dimensions. A higher dimensional\ngeneralization of Harper equation is obtained for tight-binding systems."
    },
    {
        "anchor": "Real-time quantum dynamics, path integrals and the method of thimbles: Direct numerical evaluation of the real-time path integral has a well-known\nsign problem that makes convergence exponentially slow. One promising remedy is\nto use Picard-Lefschetz theory to flow the domain of the field variables into\nthe complex plane, where the integral is better behaved. By Cauchy's theorem,\nthe final value of the path integral is unchanged. Previous analyses have\nconsidered the case of real scalar fields in thermal equilibrium, employing a\nclosed Schwinger-Keldysh time contour, allowing the evaluation of the full\nquantum correlation functions. Here we extend the analysis by not requiring a\nclosed time path, instead allowing for an initial density matrix for\nout-of-equilibrium initial value problems. We are able to explicitly implement\nGaussian initial conditions, and by separating the initial time and the later\ntimes into a two-step Monte-Carlo sampling, we are able to avoid the phenomenon\nof multiple thimbles. In fact, there exists one and only one thimble for each\nsample member of the initial density matrix. We demonstrate the approach\nthrough explicitly computing the real-time propagator for an interacting scalar\nin 0+1 dimensions, and find very good convergence allowing for comparison with\nperturbation theory and the classical-statistical approximation to real-time\ndynamics.",
        "positive": "Kaon decays and other hadronic processes in lattice QCD: This thesis deals with the study of properties and interactions of light\nmesons. Specifically, we focus on hadronic decay and scattering processes,\nwhich are dominated by effects of the strong interaction in the low-energy\nregime. A peculiarity of the strong interaction is that perturbative expansions\nfail at hadronic energy scales. Thus, genuine nonperturbative tools are\nessential to obtain first-principles predictions. Here we use Lattice Field\nTheory, and Effective Field Theories. The mathematical formulation of Quantum\nChromodynamics (QCD) and the methods to resolve its dynamics will be addressed\nin Chapter 1. The research of this dissertation is divided in two parts.\nChapter 2 describes our study of the 't Hooft limit of QCD using lattice\nsimulations, while in Chapter 3 we consider processes that involve\nmultiparticle states. The 't Hooft limit provides a simplification of\nnonabelian gauge theories that leads to nonperturbative predictions. We will\nanalyze the scaling with the number of colours of various observables, such as\nmeson masses, decay constants and weak matrix elements. A question we address\nis the origin of the long-standing puzzle of the $\\Delta I=1/2$ rule, that is,\nthe large hierarchy in the isospin amplitudes of the $K \\to \\pi\\pi$ weak decay.\nRegarding multiparticle processes, we will discuss generalizations of the\nL\\\"uscher formalism to explore three-particle processes from lattice\nsimulations. The focus will be on our contributions, such as our implementation\nof the finite-volume formalism that includes higher partial waves, and the\nfirst application of the formalism to a full lattice QCD spectrum. We will also\ncomment on the extension of the approach to generic three-pion systems. A\nsummary in Spanish will be given in Chapter 4. The final part of the thesis\n(Part II) includes the peer-reviewed publications in their original published\nform."
    },
    {
        "anchor": "Octet Baryon Masses in Partially Quenched Chiral Perturbation Theory: The mass spectrum of the lowest lying octet baryons is calculated to\nnext-to-next-to-leading order in heavy baryon chiral perturbation theory and\npartially quenched heavy baryon chiral perturbation theory. We work in the\nisospin limit and treat the decuplet baryons as dynamical fields. These results\nare necessary for extrapolating QCD and partially quenched QCD lattice\nsimulations of the octet baryon masses.",
        "positive": "Delta I=3/2, K to Pi Pi Decays with Light, Non-Zero Momentum Pions: Delta I=3/2, K to Pi Pi matrix elements are calculated on 68 configurations\nof quenched 24^3 x 64 lattices using the DBW2 action, and domain wall fermions\nwith L_s=16. The lattice spacing is a^(-1)=1.3 GeV, corresponding to a physical\nvolume of (3.6 fm)^3, which allows us to simulate a pion mass of m_Pi=227.6(6)\nMeV and a kaon mass of m_K=564(2) MeV. Twisted boundary conditions are used to\ngive the two pions momentum. One twist corresponds to a pion momentum of\np=Pi/L=170 MeV, which represents a decay that is nearly on-shell. Results for\ntime separations of 20, 24, 28, and 32 between the kaon and the two pions are\ncomputed and an error weighted average is performed to reduced the error. The\nmatrix elements are then found to have errors of order 3-4% for momentum 0 and\nPi/L, 7% for momentum sqrt(2)*Pi/L, and 15% for momentum sqrt(3)*Pi/L."
    },
    {
        "anchor": "Radiative corrections to leptonic decays using infinite-volume\n  reconstruction: Lattice QCD calculations of leptonic decay constants have now reached\nsub-percent precision so that isospin-breaking corrections, including QED\neffects, must be included to fully exploit this precision in determining\nfundamental quantities, in particular the elements of the\nCabibbo-Kobayashi-Maskawa (CKM) matrix, from experimental measurements. A\nnumber of collaborations have performed, or are performing, such computations.\nIn this paper we develop a new theoretical framework, based on Infinite-Volume\nReconstruction (IVR), for the computation of electromagnetic corrections to\nleptonic decay widths. In this method, the hadronic correlation functions are\nfirst processed theoretically in infinite volume, in such a way that the\nrequired matrix elements can be determined non-perturbatively from lattice QCD\ncomputations with finite-volume uncertainties which are exponentially small in\nthe volume. The cancellation of infrared divergences in this framework is\nperformed fully analytically. We also outline how this IVR treatment can be\nextended to determine the QED effects in semi-leptonic kaon decays with a\nsimilar degree of accuracy.",
        "positive": "Perturbative study of renormalization and mixing for asymmetric\n  staple-shaped Wilson-line operators on the lattice: We present one-loop perturbative results of the renormalization functions for\na complete set of nonlocal quark bilinear operators containing an asymmetric\nstaple-shaped Wilson line, using a family of improved lattice actions. This\nstudy is relevant for the nonperturbative investigations regarding the\nrenormalization of the unpolarized, helicity and transversity\ntransverse-momentum dependent parton distribution functions (TMDPDFs) in\nlattice QCD. We employ a number of different versions of\nregularization-independent (RI$'$) renormalization prescriptions which address\nthe power and logarithmic divergences of such nonlocal operators, the\npinch-pole singularities at infinite Wilson-line lengths, as well as the mixing\namong operators of different Dirac structures, as dictated by discrete\nsymmetries. All cancelations of divergences and admixtures are confirmed by our\nresults at one-loop level. We compare all the different prescriptions and we\nprovide the conversion matrices at one-loop order which relate the matrix\nelements of the staple operators in RI$'$ to the reference scheme\n$\\overline{\\rm MS}$."
    },
    {
        "anchor": "Probing the ground state in gauge theories: We consider two very different models of the flux tube linking two heavy\nquarks: a string linking the matter fields and a Coulombic description of two\nseparately gauge invariant charges. We compare how close they are to the\nunknown true ground state in compact U(1) and the SU(2) Higgs model.\nSimulations in compact U(1) show that the string description is better in the\nconfined phase but the Coulombic description is best in the deconfined phase;\nthe last result is shown to agree with analytical calculations. Surprisingly in\nthe non-abelian theory the Coulombic description is better in both the Higgs\nand confined phases. This indicates a significant difference in the width of\nthe flux tubes in the two theories.",
        "positive": "Improving Lattice Quark Actions: We explore the first stage of the Symanzik improvement program for lattice\nDirac fermions, namely the construction of doubler-free, highly improved\nclassical actions on isotropic as well as anisotropic lattices (where the\ntemporal lattice spacing, a_t, is smaller than the spatial one). Using field\ntransformations to eliminate doublers, we derive the previously presented\nisotropic D234 action with O(a^3) errors, as well as anisotropic D234 actions\nwith O(a^4) or O(a_t^3, a^4) errors. Besides allowing the simulation of heavy\nquarks within a relativistic framework, anisotropic lattices alleviate\npotential problems due to unphysical branches of the quark dispersion relation\n(which are generic to improved actions), facilitate studies of lattice\nthermodynamics, and allow accurate mass determinations for particles with bad\nsignal/noise properties, like glueballs and P-state mesons. We also show how\nfield transformations can be used to completely eliminate unphysical branches\nof the dispersion relation. Finally, we briefly discuss future steps in the\nimprovement program."
    },
    {
        "anchor": "Lattice study of trapped fermions at unitarity: We present a lattice study of up to N=20 unitary fermions confined to a\nharmonic trap. Our preliminary results show better than 1% agreement with high\nprecision solutions to the many-body Schrodinger equation for up to N=6. We are\nable to make predictions for larger N which were inaccessible by the\nHamiltonian approach due to computational limitations. Harmonic traps are used\nexperimentally to study cold atoms tuned to a Feshbach resonance. We show that\nthey also provide certain benefits to numerical studies of many-body\ncorrelators on the lattice. In particular, we anticipate that the methods\ndescribed here could be used for studying nuclear physics.",
        "positive": "Disorder parameter and canonical quantization approach in lattice gauge\n  theory: The work is dedicated to the derivation of the 'functional' integral\nrepresentation of the disorder parameter. This derivation resolves the problem\nof the choice of the so called modifed action as well as the problem of the\nchoice of the boundary conditions along the 'time' direction. The question of\nthe gauge fixing in the functional integral representation is also discussed."
    },
    {
        "anchor": "Axial Nucleon and Nucleon to Delta form fractors and the\n  Goldberger-Treiman Relations from Lattice QCD: We evaluate the nucleon axial form factor, $G_A(q^2)$, and induced\npseudoscalar form factor, $G_p(q^2)$, as well as the pion-nucleon form factor,\n$G_{\\pi N N}(q^2)$, in lattice QCD. We also evaluate the corresponding nucleon\nto $\\Delta$ transition form factors, $C_5^A(q^2)$ and $C_6^A(q^2)$, and the\npion-nucleon-$\\Delta$ form factor $G_{\\pi N\\Delta}(q^2)$. The nucleon form\nfactors are evaluated in the quenched theory and with two degenerate flavors of\ndynamical Wilson fermions. The nucleon to $\\Delta$ form factors, besides Wilson\nfermions, are evaluated using domain wall valence fermions with staggered sea\nquark configurations for pion masses as low as about 350 MeV. Using these form\nfactors, together with an evaluation of the renormalized quark mass, we\ninvestigate the validity of the diagonal and non-diagonal Goldberger-Treiman\nrelations. The ratios $G_{\\pi N\\Delta}(q^2)/G_{\\pi NN}(q^2)$ and\n$2C_5^A(q^2)/G_A(q^2)$ are constant as a function of the momentum transfer\nsquared and show almost no dependence on the quark mass. We confirm equality of\nthese two ratios consistent with the Goldberger-Treiman relations extracting a\nmean value of $1.61(2)$.",
        "positive": "Full CKM matrix with lattice QCD: We show that it is now possible to fully determine the CKM matrix, for the\nfirst time, using lattice QCD. |V_{cd}|, |V_{cs}|, |V_{ub}|, |V_{cb}| and\n|V_{us}| are, respectively, directly determined with our lattice results for\nform factors of semileptonic D->pi l nu, D->K l nu, B->pi l nu, B->D l nu, and\nK->pi l nu decays. The error from the quenched approximation is removed by\nusing the MILC unquenched lattice gauge configurations, where the effect of u,d\nand s quarks is included. The error from the ``chiral'' extrapolation\n(m_l->m_{ud}) is greatly reduced by using improved staggered quarks. The\naccuracy is comparable to that of the Particle Data Group averages. In\naddition, |V_{ud}|, |V_{tb}|, |V_{ts}| and |V_{td}| are determined by using\nunitarity of the CKM matrix and the experimental result for sin{(2beta)}. In\nthis way, we obtain all 9 CKM matrix elements, where the only theoretical input\nis lattice QCD. We also obtain all the Wolfenstein parameters, for the first\ntime, using lattice QCD."
    },
    {
        "anchor": "Recent progress on hadron spectroscopy from lattice QCD: Lattice QCD has matured to a degree where it is now possible to study excited\nhadrons as they truly appear in nature, as short-lived resonant enhancements\ndecaying into multiple possible final states. Through variational analysis of\nmatrices of correlation functions computed with large bases of interpolating\nfields it has proven possible to extract many excited state energy levels, and\nthese can be used to constrain the hadron-hadron scattering amplitudes in which\nhadron resonances can be observed. Recent progress is illustrated with several\nexamples including coupled-channel scattering in the $\\pi \\eta, K\\overline{K}$\nand $\\pi\\pi, K\\overline{K}, \\eta\\eta$ systems in which the $a_0, f_0$ scalar\nmesons appear.",
        "positive": "Rotated twisted-mass: a convenient regularization scheme for isospin\n  breaking QCD and QED lattice calculations: We propose a scheme of lattice twisted-mass fermion regularization which is\nparticularly convenient for application to isospin breaking (IB) QCD and QED\ncalculations, based in particular on the so called RM123 approach, in which the\nIB terms of the action are treated as a perturbation. The main, practical\nadvantage of this scheme is that it allows the calculation of IB effects on\nsome mesonic observables, like e.g. the pi+ - pi0 mass splitting, using lattice\ncorrelation functions in which the quark and antiquark fields in the meson are\nregularized with opposite values of the Wilson parameter r. These correlation\nfunctions are found to be affected by much smaller statistical fluctuations,\nwith respect to the analogous functions in which quark and antiquark fields are\nregularized with the same value of r. Two numerical application of this scheme,\nthat we call \"rotated twisted-mass\", within pure QCD and QCD+QED respectively,\nare also provided for illustration."
    },
    {
        "anchor": "Thermal momentum distribution from path integrals with shifted boundary\n  conditions: For a thermal field theory formulated in the grand canonical ensemble, the\ndistribution of the total momentum is an observable characterizing the thermal\nstate. We show that its cumulants are related to thermodynamic potentials. In a\nrelativistic system for instance, the thermal variance of the total momentum is\na direct measure of the enthalpy. We relate the generating function of the\ncumulants to the ratio of (a) a partition function expressed as a Matsubara\npath integral with shifted boundary conditions in the compact direction, and\n(b) the ordinary partition function. In this form the generating function is\nwell suited for Monte-Carlo evaluation, and the cumulants can be extracted\nstraightforwardly. We test the method in the SU(3) Yang-Mills theory and obtain\nthe entropy density at three different temperatures.",
        "positive": "Individual Eigenvalue Distributions for the Wilson Dirac Operator: We derive the distributions of individual eigenvalues for the Hermitian\nWilson Dirac Operator D5 as well as for real eigenvalues of the Wilson Dirac\nOperator DW. The framework we provide is valid in the epsilon regime of chiral\nperturbation theory for any number of flavours Nf and for non-zero low energy\nconstants W6, W7, W8. It is given as a perturbative expansion in terms of the\nk-point spectral density correlation functions and integrals thereof, which in\nsome cases reduces to a Fredholm Pfaffian. For the real eigenvalues of DW at\nfixed chirality nu this expansion truncates after at most nu terms for small\nlattice spacing \"a\". Explicit examples for the distribution of the first and\nsecond eigenvalue are given in the microscopic domain as a truncated expansion\nof the Fredholm Pfaffian for quenched D5, where all k-point densities are\nexplicitly known from random matrix theory. For the real eigenvalues of\nquenched DW at small \"a\" we illustrate our method by the finite expansion of\nthe corresponding Fredholm determinant of size nu."
    },
    {
        "anchor": "Testing the $SU(4)$ degeneracy after low-mode removal with $J=2$ mesons: Recent lattice results on Dirac low-mode removed $J=1,2$ mesons and\n$J=\\frac{1}{2}$ baryons reveal the appearance of a new $SU(4)$ symmetry of\nconfinement. Here the degeneracy of all $J=2$ iso-vector states within an\nirreducible representation of $SU(4)$ after low-mode removal is demonstrated.\nThe $SU(4)$ symmetry contains $SU(2)_L \\times SU(2)_R$ and $U(1)_A$ symmetries\nas subgroups and mixes all compontents $u_L,u_R,d_L,d_R$ of the two-flavor\nDirac field. It implies the vanishing of the interaction of quarks with the\ncolor-magnetic field, which is shown by using the QCD Hamiltonian in Coulomb\ngauge.",
        "positive": "Non-perturbative renormalization of quark bilinear operators with Nf=2\n  (tmQCD) Wilson fermions and the tree-level improved gauge action: We present results for the renormalization constants of bilinear quark\noperators obtained by using the tree-level Symanzik improved gauge action and\nthe Nf=2 twisted mass fermion action at maximal twist, which guarantees\nautomatic O(a)-improvement. Our results are also relevant for the corresponding\nstandard (un-twisted) Wilson fermionic action since the two actions only\ndiffer, in the massless limit, by a chiral rotation of the quark fields. The\nscale-independent renormalization constants ZV, ZA and the ratio ZP/ZS have\nbeen computed using the RI-MOM approach, as well as other alternative methods.\nFor ZA and ZP/ZS, the latter are based on both standard twisted mass and\nOsterwalder-Seiler fermions, while for ZV a Ward Identity has been used. The\nquark field renormalization constant Zq and the scale dependent renormalization\nconstants ZS, ZP and ZT are determined in the RI-MOM scheme. Leading\ndiscretization effects of O(g^2 a^2), evaluated in one-loop perturbation\ntheory, are explicitly subtracted from the RI-MOM estimates."
    },
    {
        "anchor": "Symplectic lattice gauge theories on Grid: approaching the conformal\n  window: Symplectic gauge theories coupled to matter fields lead to symmetry\nenhancement phenomena that have potential applications in such diverse contexts\nas composite Higgs, top partial compositeness, strongly interacting dark\nmatter, and dilaton-Higgs models. These theories are also interesting on\ntheoretical grounds, for example in reference to the approach to the large-N\nlimit. A particularly compelling research aim is the determination of the\nextent of the conformal window in gauge theories with symplectic groups coupled\nto matter, for different groups and for field content consisting of fermions\ntransforming in different representations. Such determination would have\nfar-reaching implications, but requires overcoming huge technical challenges.\n  Numerical studies based on lattice field theory can provide the quantitative\ninformation necessary to this endeavour. We developed new software to implement\nsymplectic groups in the Monte Carlo algorithms within the Grid framework. In\nthis paper, we focus most of our attention on the Sp(4) lattice gauge theory\ncoupled to four (Wilson-Dirac) fermions transforming in the 2-index\nantisymmetric representation, as a case study. We discuss an extensive\ncatalogue of technical tests of the algorithms and present preliminary\nmeasurements to set the stage for future large-scale numerical investigations.\nWe also include the scan of parameter space of all asymptotically free Sp(4)\nlattice gauge theories coupled to varying number of fermions transforming in\nthe antisymmetric representation.",
        "positive": "Baryon number and charge fluctuations from lattice QCD: We calculate electric and baryonic charge fluctuations on the lattice.\nResults have been obtained with the highly improved staggered quark action\n(HISQ) and almost physical quark masses on lattices with spacial extent of\n$N_\\tau=6,8,12$. Higher order cumulants of the net-charge distributions are\nincreasingly dominated by a universal scaling behavior, which is arising due to\na critical point of QCD in the chiral limit. Considering cumulants up to the\nsixth order, we observe that they generically behave as expected from universal\nscaling laws, which is quite different from the cumulants calculated within the\nhadron resonance gas model. Taking ratios of these cumulants, we obtain volume\nindependent results that can be compared to the experimental measurements. Such\na comparison will unambiguously relate the QCD transition temperature that has\nbeen determined on the lattice with the freeze out temperature of heavy ion\ncollision at LHC and RHIC."
    },
    {
        "anchor": "Eigenvalue spectrum of massless Dirac operators on the lattice: We present a detailed study of the interplay between chiral symmetry and\nspectral properties of the Dirac operator in lattice gauge theories. We\nconsider, in the framework of the Schwinger model, the fixed point action and a\nfermion action recently proposed by Neuberger. Both actions show the remnant of\nchiral symmetry on the lattice as formulated in the Ginsparg-Wilson relation.\nWe check this issue for practical implementations, also evaluating the fermion\ncondensate in a finite volume by a subtraction procedure. Moreover, we\ninvestigate the distribution of the eigenvalues of a properly defined\nanti-hermitian lattice Dirac operator, studying the statistical properties at\nthe low lying edge of the spectrum. The comparison with the predictions of\nchiral Random Matrix Theory enables us to obtain an estimate of the infinite\nvolume fermion condensate.",
        "positive": "Monopole Order Parameter in SU(2) Lattice Gauge Theory: We present the results of the numerical calculation of the probability\ndistribution of the value of the monopole creation operator in $SU(2)$ lattice\ngluodynamics. We work in the maximal abelian projection. It occurs that at the\nlow temperature, below the deconfinement phase transition the maximum of the\ndistribution is shifted from zero, which means that the effective constraint\npotential is of the Higgs type. Above the phase transition the minimum of the\npotential (the maximum of the monopole field distribution) is at the zero value\nof the monopole field. This is the direct proof of the existence of the abelian\nmonopole condensate in the confinement phase of the gluodynamics, which\nconfirms the dual superconductor model of the confining vacuum."
    },
    {
        "anchor": "Topology and pion correlators -- a study in the N_f=2 Schwinger model: I readdress the issue whether the topological charge of the gauge background\nhas an influence on a hadronic observable. To this end pion correlators in the\nSchwinger model with 2 dynamical flavours are determined on subensembles with a\nfixed topological charge. It turns out that the answer depends on a specific\nfunction of the sea-quark mass and the box volume which is in close analogy to\nthe Leutwyler-Smilga parameter in full QCD.",
        "positive": "Quenched penguins and the Delta I=1/2 rule: The transformation properties of strong penguin operators under the action of\nthe flavor group change when they are considered as operators in (partially)\nquenched QCD instead of the unquenched theory. As a result, additional\noperators and new low-energy constants appear in the effective theory\ndescribing non-leptonic kaon decay matrix elements in the partially quenched\nsetting. These new low-energy constants do not have a counterpart in the\nunquenched theory, and should thus be considered as an artifact of the quenched\napproximation. Here we consider strong penguin operators consisting of products\nof two left-handed flavor currents, and give a complete one-loop analysis in\nthe effective theory for K^0 to vacuum and K^+ to pi^+ matrix elements. We find\nthat the new low-energy constants already appear in these matrix elements at\nleading order. This implies that (partially) quenched lattice computations of\nfor instance the Delta I=1/2 rule are affected by ambiguities intrinsic to the\nuse of the quenched approximation at leading order. The only exception is the\npartially quenched case with three light sea quarks, consistent with general\nexpectations. Our results are also relevant when the charm quark is kept in the\ntheory."
    },
    {
        "anchor": "Coulomb, Landau and Maximally Abelian Gauge Fixing in Lattice QCD with\n  Multi-GPUs: A lattice gauge theory framework for simulations on graphic processing units\n(GPUs) using NVIDIA's CUDA is presented. The code comprises template classes\nthat take care of an optimal data pattern to ensure coalesced reading from\ndevice memory to achieve maximum performance. In this work we concentrate on\napplications for lattice gauge fixing in 3+1 dimensional SU(3) lattice gauge\nfield theories. We employ the overrelaxation, stochastic relaxation and\nsimulated annealing algorithms which are perfectly suited to be accelerated by\nhighly parallel architectures like GPUs. The applications support the Coulomb,\nLandau and maximally Abelian gauges. Moreover, we explore the evolution of the\nnumerical accuracy of the SU(3) valued degrees of freedom over the runtime of\nthe algorithms in single (SP) and double precision (DP). Therefrom we draw\nconclusions on the reliability of SP and DP simulations and suggest a mixed\nprecision scheme that performs the critical parts of the algorithm in full DP\nwhile retaining 80-90% of the SP performance. Finally, multi-GPUs are adopted\nto overcome the memory constraint of single GPUs. A communicator class which\nhides the MPI data exchange at the boundaries of the lattice domains, via the\nlow bandwidth PCI-Bus, effectively behind calculations in the inner part of the\ndomain is presented. Linear scaling using 16 NVIDIA Tesla C2070 devices and a\nmaximum performance of 3.5 Teraflops on lattices of size down to 64^3 x 256 is\ndemonstrated.",
        "positive": "Flux tubes and coherence length in the SU(3) vacuum: An estimate of the London penetration and coherence lengths in the vacuum of\nthe SU(3) pure gauge theory is given downstream an analysis of the transverse\nprofile of the chromoelectric flux tubes. Within ordinary superconductivity, a\nsimple variational model for the magnitude of the normalized order parameter of\nan isolated vortex produces an analytic expression for magnetic field and\nsupercurrent density. In the picture of SU(3) vacuum as dual superconductor,\nthis expression provides us with the function that fits the chromoelectric\nfield data. The smearing procedure is used in order to reduce noise."
    },
    {
        "anchor": "The SU(3) Sextet Model with Wilson Fermions: We investigate the spectrum and IR properties of the SU(3) \"sextet\" model\nwith two Dirac fermions in the two-index symmetric representation via lattice\nsimulations. This model is a prime candidate for a realization of Walking\nTechnicolor, which features a minimal matter content and it is expected to be\ninside or very close to the lower boundary of the conformal window. We use the\nWilson discretization for the fermions and map the phase structure of the\nlattice model. We study several spectral and gradient flow observables both in\nthe bulk and the weak coupling phases. While in the bulk phase we find clear\nsigns of chiral symmetry breaking, in the weak coupling phase there is no clear\nindication for it, and instead the chiral limit of the model seems compatible\nwith an IR-conformal behavior.",
        "positive": "Renormalization $\\&$ improvement of the tensor operator for $N_f=3$ QCD\n  in a $\u03c7$SF setup: We present preliminary results of the non-perturbative renormalization group\n(RG) running of the flavor non-singlet tensor operator. We employ the $\\chi$SF\nscheme for $N_f=3$ QCD using ensembles generated by the ALPHA collaboration for\nthe computation of the quark mass running. The $\\chi$SF property of automatic\n$O(a)$ improvement prevents the $O(a)$ mixing of the correlation functions."
    },
    {
        "anchor": "Isoscalar electromagnetic form factors of the nucleon in $N_\\mathrm{f} =\n  2 + 1$ lattice QCD: We present results for the isoscalar electromagnetic form factors of the\nnucleon computed on the Coordinated Lattice Simulations (CLS) ensembles with\n$N_\\mathrm{f} = 2 + 1$ flavors of $\\mathcal{O}(a)$-improved Wilson fermions and\nan $\\mathcal{O}(a)$-improved conserved vector current. In order to estimate the\nexcited-state contamination, we employ several source-sink separations and\napply the summation method. For the computation of the quark-disconnected\ndiagrams, a stochastic estimation based on the one-end trick is performed, in\ncombination with a frequency-splitting technique and the hopping parameter\nexpansion. By these means, we obtain a clear signal for the form factors\nincluding the quark-disconnected contributions, which have a statistically\nsignificant effect on our results.",
        "positive": "Heavy-Quark Masses from the Fermilab Method in Three-Flavor Lattice QCD: We report on heavy quark mass calculations using Fermilab heavy quarks.\nLattice calculations of heavy-strange meson masses are combined with one-loop\n(automated) lattice perturbation theory to arrive at the quark mass. Mesons are\nconstructed from Fermilab heavy quarks and staggered light quarks. We use the\nMILC ensembles at three lattice spacings and sea quark mass ratios of $m_{\\rm\nu,d} / m_{\\rm s} = 0.1$ to 0.4. Preliminary results for the bottom quark are\ngiven in the potential subtracted scheme."
    },
    {
        "anchor": "Two-Point Functions of Four-Dimensional Simplicial Quantum Gravity: We investigate the interaction mechanism of pure quantum gravity in Regge\ndiscretization. We compute volume-volume and link-link correlation functions.\nIn a preliminary analysis the forces turn out to be of Yukawa type, at least on\nour finite lattice being away from the continuum limit.",
        "positive": "A Review of Pentaquark Calculations on the Lattice: We review lattice calculations of pentaquarks and discuss issues pertaining\nto interpolation fields, distinguishing the signal of pentaquarks from those of\nthe KN scattering states, chiral symmetry, and ghost state contaminations."
    },
    {
        "anchor": "Towards the continuum limit in transport coefficient computations: The analytic continuation needed for the extraction of transport coefficients\nnecessitates in principle a continuous function of the Euclidean time variable.\nWe report on progress towards achieving the continuum limit for 2-point\ncorrelator measurements in thermal SU(3) gauge theory, with specific attention\npaid to scale setting. In particular, we improve upon the determination of the\ncritical lattice coupling and the critical temperature of pure SU(3) gauge\ntheory, estimating r0*Tc ~ 0.7470(7) after a continuum extrapolation. As an\napplication the determination of the heavy quark momentum diffusion coefficient\nfrom a correlator of colour-electric fields attached to a Polyakov loop is\ndiscussed.",
        "positive": "A local fermion update algorithm for SYM quantum mechanics: We present a local fermion update algorithm for N=4 supersymmetric Yang-Mills\nquantum mechanics which allows simulations in fixed canonical sectors. We\ndiscuss some aspects of the physics of this theory, including the appearance of\nflat directions in the bosonic potential and the metastabilities related to\nthose. In particular, we show that the modulus of the bosonic fields diverges\nin some of the fermion sectors and for thermal boundary conditions."
    },
    {
        "anchor": "Efficient Hadronic Operators in Lattice Gauge Theory: We study operators to create hadronic states made of light quarks in quenched\nlattice gauge theory. We construct non-local gauge-invariant operators which\nprovide information about the spatial extent of the ground state and excited\nstates. The efficiency of the operators is shown by looking at the wave\nfunction of the first excited state, which has a node as a function of the\nspatial extent of the operator. This allows one to obtain an uncontaminated\nground state for hadrons.",
        "positive": "The excited hadron spectrum in lattice QCD using a new variance\n  reduction method: Progress in calculating the spectrum of excited baryons and mesons in lattice\nQCD is described. Correlation matrices of sets of spatially-extended hadron\noperators have been studied and their effectiveness in facilitating the\nextraction of excited-state energies is demonstrated. First applications of the\nstochastic LapH method, a new method of estimating the low-lying effects of\nquark propagation, are presented."
    },
    {
        "anchor": "Nonperturbative Lattice Simulation of High Multiplicity Cross Section\n  Bound in $\u03c6^4_3$ on Beowulf Supercomputer: In this thesis, we have investigated the possibility of large cross sections\nat large multiplicity in weakly coupled three dimensional $\\phi^4$ theory using\nMonte Carlo Simulation methods. We have built a Beowulf Supercomputer for this\npurpose. We use spectral function sum rules to derive a bound on the total\ncross section where the quantity determining the bound can be measured by Monte\nCarlo simulation in Euclidean space. We determine the critical threshold energy\nfor large high multiplicity cross section according to the analysis of M.B.\nVolosion and E.N. Argyres, R.M.P. Kleiss, and C.G. Papadopoulos. We compare the\nsimulation results with the perturbation results and see no evidence for large\ncross section in the range where tree diagram estimates suggest they should\nexist.",
        "positive": "Instantaneous stochastic perturbation theory: A form of stochastic perturbation theory is described, where the\nrepresentative stochastic fields are generated instantaneously rather than\nthrough a Markov process. The correctness of the procedure is established to\nall orders of the expansion and for a wide class of field theories that\nincludes all common formulations of lattice QCD."
    },
    {
        "anchor": "Y(4260) on the lattice: We investigate the mass spectra of closed-charm mesons with $ J^{PC} = 1^{--}\n$, for hybrid charmonium, molecules, and diquark-antidiquark operators, in\nquenched lattice QCD with exact chiral symmetry. For two lattice volumes $ 24^3\n\\times 48 $ and $ 20^3 \\times 40 $, each of 100 gauge configurations generated\nwith single-plaquette action at $ \\beta = 6.1 $, we compute point-to-point\nquark propagators and measure the time-correlation functions of these exotic\nmeson operators. For the molecular operator $\n\\{(\\qbar\\gamma_5\\gamma_i\\c)(\\cbar\\gamma_5\\q)-\n  (\\cbar\\gamma_5\\gamma_i\\q)(\\qbar\\gamma_5\\c) \\} $, it detects a resonance with\nmass around $ 4238 \\pm 31 $ MeV, which is naturally identified with $ Y(4260)\n$. Further, for any molecular and diquark-antidiquark operator, it detects\nheavier exotic charmed mesons, with quark content $ (\\c\\s\\cbar\\sbar) $ around $\n4450 \\pm 100 $ MeV, and $ (\\c\\c\\cbar\\cbar) $ around $ 6400 \\pm 50 $ MeV.",
        "positive": "Flowing Gauge Theories: Finite-Density $QED_{1+1}$: Finite-density calculations in lattice field theory are typically plagued by\nsign problems. A promising way to ameliorate this issue is the holomorphic flow\nequations that deform the manifold of integration for the path integral to\nmanifolds in the complex space where the sign fluctuations are less dramatic.\nWe discuss some novel features of applying the flow equations to gauge theories\nand present results for finite-density $QED_{1+1}$."
    },
    {
        "anchor": "Topological susceptibility in lattice Yang-Mills theory with open\n  boundary condition: We find that using open boundary condition in the temporal direction can\nyield the expected value of the topological susceptibility in lattice SU(3)\nYang-Mills theory. As a further check, we show that the result agrees with\nnumerical simulations employing the periodic boundary condition. Our results\nsupport the preferability of the open boundary condition over the periodic\nboundary condition as the former allows for computation at smaller lattice\nspacings needed for continuum extrapolation at a lower computational cost.",
        "positive": "Improved lattice method for determining entanglement measures in SU(N)\n  gauge theories: The determination of entanglement measures in SU(N) gauge theories is a\nnon-trivial task. With the so-called \"replica trick\", a family of entanglement\nmeasures, known as \"R\\'enyi entropies\", can be determined with lattice Monte\nCarlo. Unfortunately, the standard implementation of the replica method for\nSU(N) lattice gauge theories suffers from a severe signal-to-noise ratio\nproblem, rendering high-precision studies of R\\'enyi entropies prohibitively\nexpensive. In this work, we propose a method to overcome the signal-to-noise\nratio problem and show some first results for SU(N) in 4 dimensions."
    },
    {
        "anchor": "Electric Dipole Moment Results from lattice QCD: We utilize the gradient flow to define and calculate electric dipole moments\ninduced by the strong QCD $\\theta$-term and the dimension-6 Weinberg operator.\nThe gradient flow is a promising tool to simplify the renormalization pattern\nof local operators. The results of the nucleon electric dipole moments are\ncalculated on PACS-CS gauge fields (available from the ILDG) using $N_{f}=2+1$,\nof discrete size $32^{3}\\times 64$ and spacing $a \\simeq 0.09$ fm. These gauge\nfields use a renormalization-group improved gauge action and a\nnon-perturbatively $O(a)$ improved clover quark action at $\\beta = 1.90$, with\n$c_{SW} = 1.715$. The calculation is performed at pion masses of $m_{\\pi}\n\\simeq 411,701$ MeV.",
        "positive": "Gauge fixing methods and Gribov copies effects in lattice QCD: We compare two Landau gauge fixing methods, aiming to find the global maximum\nof the gauge fixing functional. Moreover, a systematic effect of Gribov copies\nin the gluon and ghost propagators computed in Landau gauge is presented and\ndiscussed."
    },
    {
        "anchor": "SO(2N) and SU(N) gauge theories: We present our preliminary results of SO(2N) gauge theories, approaching the\nlarge-N limit. SO(2N) theories may help us to understand QCD at finite chemical\npotential since there is an orbifold equivalence between SO(2N) and SU(N) gauge\ntheories at large-N and SO(2N) theories do not have the sign problem present in\nQCD. We consider the string tensions, mass spectra, and deconfinement\ntemperatures in the SO(2N) pure gauge theories in 2+1 dimensions, comparing\nthem to their corresponding SU(N) theories.",
        "positive": "Proton Helicity GPDs from Lattice QCD: First lattice QCD calculations of $x$-dependent GPD have been performed in\nthe (symmetric) Breit frame, where the momentum transfer is evenly divided\nbetween the initial and final hadron states. However, employing the asymmetric\nframe, we are able to obtain proton GPDs for multiple momentum transfers in a\ncomputationally efficient setup. In these proceedings, we focus on the helicity\ntwist-2 GPD at zero skewness that gives access to the $\\widetilde{H}$ GPD. We\nwill cover the implementation of the asymmetric frame, its comparison to the\nBreit frame, and the dependence of the GPD on the squared four-momentum\ntransfer, $-t$. The calculation is performed on an $N_f = 2+1+1$ ensemble of\ntwisted mass fermions with a clover improvement. The mass of the pion for this\nensemble is roughly 260 MeV."
    },
    {
        "anchor": "Nucleon-Pion Spectroscopy from Sparsened Correlators: Neutrino oscillation experiments require accurate reconstructions of neutrino\nenergies, which depend in part on a theoretical understanding of the axial $N\n\\rightarrow \\Delta$ transition form factors. Lattice QCD studies of this\ntransition require construction of all hadronic states with energies up to the\nmass of the $\\Delta$ resonance, which includes $N\\pi$ and $N\\pi\\pi$ for\nphysical quark mass values. Building interpolating operators from sparse grids\nof source and sink points is a versatile method of approximating all-to-all\nquark propagators that has been successfully used in other multi-hadron\ncalculations. This work will discuss applications of this method to $N\\pi$ and\n$N\\pi\\pi$ systems and present preliminary results.",
        "positive": "Numerical tests of the electroweak phase transition and thermodynamics\n  of the electroweak plasma: The finite temperature phase transition in the SU(2) Higgs model at a Higgs\nboson mass $M_H \\simeq 34$ GeV is studied in numerical simulations on\nfour-dimensional lattices with time-like extensions up to $L_t=5$. The effects\nof the finite volume and finite lattice spacing on masses and couplings are\nstudied in detail. The errors due to uncertainties in the critical hopping\nparameter are estimated. The thermodynamics of the electroweak plasma near the\nphase transition is investigated by determining the relation between energy\ndensity and pressure."
    },
    {
        "anchor": "A determination of the B_s^0 and B_d^0 mixing parameters in 2+1 lattice\n  QCD: We report on the advances in our unquenched calculation of the matrix\nelements relevant for the analysis of B^0-\\bar B^0 mixing using the Asqtad\n(light quark) and Fermilab (heavy quark) actions. We have calculated the\nhadronic parameters for the mass and width differences in the neutral B meson\nsystem. Preliminary results are presented for f_{B_q}^2 B_q as well as for the\nratio \\xi^2=f_{B_s}^2 B_{B_s}/f_{B_d}^2 B_{B_d}.",
        "positive": "Perturbatively improving RI-MOM renormalization constants: The determination of renormalization factors is of crucial importance in\nlattice QCD. They relate the observables obtained on the lattice to their\nmeasured counterparts in the continuum in a suitable renormalization scheme.\nTherefore, they have to be computed as precisely as possible. A widely used\napproach is the nonperturbative Rome-Southampton method. It requires, however,\na careful treatment of lattice artifacts. In this paper we investigate a method\nto suppress these artifacts by subtracting one-loop contributions to\nrenormalization factors calculated in lattice perturbation theory. We compare\nresults obtained from a complete one-loop subtraction with those calculated for\na subtraction of contributions proportional to the square of the lattice\nspacing."
    },
    {
        "anchor": "Topological susceptibility of pure gauge theory using Density of States: The topological susceptibility of the SU(3) pure gauge theory is calculated\nin the deconfined phase at temperatures up to $10T_c$. At such large\ntemperatures the susceptibility is suppressed, topologically non-trivial\nconfigurations are extremely rare. Thus, direct lattice simulations are not\nfeasible. The density of states (DoS) method is designed to simulate rare\nevents, we present an application of the DoS method to the problem of high\ntemperature topological susceptibility. We reconstruct the histogram of the\ncharge sectors that one could have obtained in a naive importance sampling. Our\nfindings are perfectly consistent with a free instanton gas.",
        "positive": "Lattice QCD simulation of the Berry curvature: The Berry curvature is a fundamental concept describing topological order of\nquantum systems. While it can be analytically tractable in non-interacting\nsystems, numerical simulations are necessary in interacting systems. We present\na formulation to calculate the Berry curvature in lattice QCD."
    },
    {
        "anchor": "Light hadron spectrum with 2+1 flavor dynamical $O(a)$-improved Wilson\n  quarks: We present preliminary results for the light harden spectrum in $N_f=2+1$\nlattice QCD obtained with the nonperturbatively $O(a)$-improved Wilson quark\naction and the Iwasaki gauge action. Simulations are carried out at\n$\\beta=1.90$ on a $32^3 \\times 64$ lattice using the PACS-CS computer. We\nemploy L\\\"uscher's domain-decomposed HMC algorithm to reduce the up-down quark\nmasses toward the physical value. The pseudoscalar meson masses range from 730\nMeV down to 210 MeV. We compare the light harden spectrum extrapolated to the\nphysical point with the experimental values.",
        "positive": "The Standard Model and the Lattice: The $SU(3)\\otimes SU(2) \\otimes U(1)$ standard model maps smoothly onto a\nconventional lattice gauge formulation, including the parity violation of the\nweak interactions. The formulation makes use of the pseudo-reality of the weak\ngroup and requires the inclusion a full generation of both leptons and quarks.\nAs in continuum discussions, chiral eigenstates of the Dirac operator generate\nknown anomalies, although with rough gauge configurations these are no longer\nexact zero modes of the Dirac operator."
    },
    {
        "anchor": "LDIC Survey 2023: Feeling Welcome in the Community: We review the level of welcomeness that members of the lattice field theory\ncommunity feel based on the results of a survey performed in May and June 2023.\nWhile respondents reported generally high levels of feeling welcome at the\nlattice conference, women and people with diverse gender identities, sexual\norientations, ethnic backgrounds and religious affiliations feel less included\nand have more negative experiences at the lattice conference than their peers.\nRespondents report that they are actively informing themselves about inequities\nin the community, however a large fraction of survey participants underestimate\nthe severity of the problem, as was found in previous surveys. The survey data\nindicate that this situation can be most effectively improved by organizing\ntalks and events about issues of diversity and inclusion within the lattice\ncommunity. Respondents also reported that individual readings of scientific\npapers on equity and inclusion are effective in giving people agency in making\na change and hence it may be helpful to collate a collection of important\narticles on these topics.",
        "positive": "nEDM from the theta-term and chromoEDM operators: In a previous work, we showed that unresolved excited state contaminations\nprovide a major source of systematic uncertainty in the calculation of the\nnucleon electric dipole moment due to the QCD topological term theta. Here we\nextend the calculation to the quark chromo-electric dipole moment operator\n(qcEDM). We also show quantitatively the impact of the mixing of the qcEDM with\nlower-dimensional operators on the lattice. Finally, we present preliminary\nresults from a unitary clover-on-clover calculation for the QCD topological\nterm."
    },
    {
        "anchor": "Non-perturbative renormalization of three-quark operators: High luminosity accelerators have greatly increased the interest in\nsemi-exclusive and exclusive reactions involving nucleons. The relevant\ntheoretical information is contained in the nucleon wavefunction and can be\nparametrized by moments of the nucleon distribution amplitudes, which in turn\nare linked to matrix elements of local three-quark operators. These can be\ncalculated from first principles in lattice QCD. Defining an RI-MOM\nrenormalization scheme, we renormalize three-quark operators corresponding to\nlow moments non-perturbatively and take special care of the operator mixing.\nAfter performing a scheme matching and a conversion of the renormalization\nscale we quote our final results in the MSbar scheme at mu=2 GeV.",
        "positive": "A quark action for very coarse lattices: We investigate a tree-level O(a^3)-accurate action, D234c, on coarse\nlattices. For the improvement terms we use tadpole-improved coefficients, with\nthe tadpole contribution measured by the mean link in Landau gauge.\n  We measure the hadron spectrum for quark masses near that of the strange\nquark. We find that D234c shows much better rotational invariance than the\nSheikholeslami-Wohlert action, and that mean-link tadpole improvement leads to\nsmaller finite-lattice-spacing errors than plaquette tadpole improvement. We\nobtain accurate ratios of lattice spacings using a convenient ``Galilean\nquarkonium'' method.\n  We explore the effects of possible O(alpha_s) changes to the improvement\ncoefficients, and find that the two leading coefficients can be independently\ntuned: hadron masses are most sensitive to the clover coefficient, while hadron\ndispersion relations are most sensitive to the third derivative coefficient\nC_3. Preliminary non-perturbative tuning of these coefficients yields values\nthat are consistent with the expected size of perturbative corrections."
    },
    {
        "anchor": "Lattice QCD constraints on the heavy quark diffusion coefficient: We report progress towards computing the heavy quark momentum diffusion\ncoefficient from the correlator of two chromo-electric fields attached to a\nPolyakov loop in pure SU(3) gauge theory. Using a multilevel algorithm and\ntree-level improvement, we study the behavior of the diffusion coefficient as a\nfunction of temperature in the wide range $1.1 < T / T_c < 10^4$ in order to\ncompare it to perturbative expansions at high temperature. We find that within\nerrors the lattice results are remarkably compatible with the next-to-leading\norder perturbative result.",
        "positive": "Heavy Quark Potentials in Quenched QCD at High Temperature: Heavy quark potentials are investigated at high temperatures. The temperature\nrange covered by the analysis extends from $T$ values just below the\ndeconfinement temperature up to about $4 T_c$ in the deconfined phase. We\nsimulated the pure gauge sector of QCD on lattices with temporal extents of 4,\n6 and 8 with spatial volumes of $32^3$. On the smallest lattice a tree level\nimproved action was employed while in the other two cases the standard Wilson\naction was used. Below $T_c$ we find a temperature dependent logarithmic term\ncontributing to the confinement potential and observe a string tension which\ndecreases with rising temperature but retains a finite value at the\ndeconfinement transition. Above $T_c$ the potential is Debye-screened, however\nsimple perturbative predictions do not apply."
    },
    {
        "anchor": "An Alternative Lattice Field Theory Formulation Inspired by Lattice\n  Supersymmetry: We propose an unconventional formulation of lattice field theories which is\nquite general, although originally motivated by the quest of exact lattice\nsupersymmetry. Two long standing problems have a solution in this context: 1)\nEach degree of freedom on the lattice corresponds to $2^d$ degrees of freedom\nin the continuum, but all these doublers have (in the case of fermions) the\nsame chirality and can be either identified, thus removing the degeneracy, or,\nin some theories with extended supersymmetry, identified with different members\nof the same supermultiplet. 2) The derivative operator, defined on the lattice\nas a suitable periodic function of the lattice momentum, is an addittive and\nconserved quantity, thus assuring that the Leibnitz rule is satisfied. This\nimplies that the product of two fields on the lattice is replaced by a\nnon-local \"star product\" which is however in general non-associative.\nAssociativity of the \"star product\" poses strong restrictions on the form of\nthe lattice derivative operator (which becomes the inverse gudermannian\nfunction of the lattice momentum) and has the consequence that the degrees of\nfreedom of the lattice theory and of the continuum theory are in one-to-one\ncorrespondence, so that the two theories are eventually equivalent.\nRegularization of the ultraviolet divergences on the lattice is not associated\nto the lattice spacing, which does not act as a regulator, but may be obtained\nby a one parameter deformation of the lattice derivative, thus preserving the\nlattice structure even in the limit of infinite momentum cutoff. However this\nregularization breaks gauge invariance and a gauge invariant regularization\nwithin the lattice formulation is still lacking.",
        "positive": "Calorons and dyons at the thermal phase transition analyzed by overlap\n  fermions: In a pilot study, we use the topological charge density defined by the\neigenmodes of the overlap Dirac operator (with ultraviolet filtering by\nmode-truncation) to search for lumps of topological charge in SU(2) pure gauge\ntheory. Augmenting this search with periodic and antiperiodic temporal boundary\nconditions for the overlap fermions, we demonstrate that the lumps can be\nclassified either as calorons or as separate caloron constituents (dyons).\nInside the topological charge clusters the (smeared) Polyakov loop is found to\nshow the typical profile characteristic for calorons and dyons. This\ninvestigation, motivated by recent caloron/dyon model studies, is performed at\nthe deconfinement phase transition for SU(2) gluodynamics on 20^3 x 6 lattices\ndescribed by the tadpole improved L\\\"uscher-Weisz action. The transition point\nhas been carefully located. As a necessary condition for the caloron/dyon\ndetection capability, we check that the LW action, in contrast to the Wilson\naction, generates lattice ensembles, for which the overlap Dirac eigenvalue\nspectrum smoothly behaves under smearing and under the change of the boundary\nconditions."
    },
    {
        "anchor": "Full nonperturbative QCD simulations with 2+1 flavors of improved\n  staggered quarks: Dramatic progress has been made over the last decade in the numerical study\nof quantum chromodynamics (QCD) through the use of improved formulations of QCD\non the lattice (improved actions), the development of new algorithms and the\nrapid increase in computing power available to lattice gauge theorists. In this\narticle we describe simulations of full QCD using the improved staggered quark\nformalism, ``asqtad'' fermions. These simulations were carried out with two\ndegenerate flavors of light quarks (up and down) and with one heavier flavor,\nthe strange quark. Several light quark masses, down to about 3 times the\nphysical light quark mass, and six lattice spacings have been used. These\nenable controlled continuum and chiral extrapolations of many low energy QCD\nobservables. We review the improved staggered formalism, emphasizing both\nadvantages and drawbacks. In particular, we review the procedure for removing\nunwanted staggered species in the continuum limit. We then describe the asqtad\nlattice ensembles created by the MILC Collaboration. All MILC lattice ensembles\nare publicly available, and they have been used extensively by a number of\nlattice gauge theory groups. We review physics results obtained with them, and\ndiscuss the impact of these results on phenomenology. Topics include the heavy\nquark potential, spectrum of light hadrons, quark masses, decay constant of\nlight and heavy-light pseudoscalar mesons, semileptonic form factors, nucleon\nstructure, scattering lengths and more. We conclude with a brief look at highly\npromising future prospects.",
        "positive": "Finite Temperature Properties of the SO(3) Lattice Gauge Theory: We make a numerical study of the finite temperature properties of the SO(3)\nlattice gauge theory. As its symmetry properties are quite different from those\nof the SU(2) LGT, a different set of observables have to be considered in this\nmodel. We study several observables, such as, the plaquette square, the Z(2)\nmonopole density, the fundamental and adjoint Wilson line, and the tiled Wilson\nline correlation function. Our simulations show that the Z(2) monopoles\ncondense at strong coupling just as in the bulk system. This transition is seen\nat approximately the same location as in the bulk system. A surprising\nobservation is the multiple valuedness of the adjoint Wilson line at high\ntemperatures. At high temperatures, we observe long lived metastable states in\nwhich the adjoint Wilson line takes positive and negative values. The numerical\nvalues of other observables in these two states appear to be almost the same.\nWe study these states using different methods and also make comparisons with\nthe high temperature behaviour of the SU(2) LGT. Finally, we discuss various\ninterpretations of our results and point out their relevance for the phase\ndiagram of the SO(3) LGT at finite temperature."
    },
    {
        "anchor": "Large-Momentum Effective Theory vs. Short-Distance Operator Expansion:\n  Contrast and Complementarity: Although equivalent in the infinite-momentum limit, large-momentum effective\ntheory (LaMET) and short-distance operator product expansion (SD-OPE) are two\ndifferent approaches to extract parton distribution functions (PDFs) from\ncoordinate-space correlation functions in large-momentum hadrons. LaMET\nimplements a momentum-space expansion in $\\Lambda_{\\rm QCD}/[x(1-x)P^z]$ to\ndirectly calculate PDFs $f(x)$ in a middle region of Bjorken $x\\in [x_{\\rm\nmin}\\sim \\Lambda_{\\rm QCD}/P^z, x_{\\rm max}\\sim 1-x_{\\min}]$. SD-OPE applies\nperturbative QCD at small Euclidean distances $z$ to extract a range\n$[0,\\lambda_{\\rm max}]$ of leading-twist correlations, $h(\\lambda=zP^z)$,\ncorresponding to the Fourier transformation of PDFs. Similar to the quantum\nmechanical uncertainty principle, an incomplete leading-twist correlation\ncannot be readily converted to a momentum-space local distribution, and the\nmethods to solve the ``inverse problem'' involve essentially modelling of the\nmissing information beyond $\\lambda_{\\rm max}$. On the other hand,\nshort-distance correlations, along with the expected end-point asymptotics, can\nbe used to phenomenologically fit the PDFs in the LaMET-complementary regions:\n$x\\in [0,x_{\\rm min}]$ and $[x_{\\rm max}, 1]$. We use the recent results of the\npion valence quark distribution from the ANL/BNL collaboration to demonstrate\nthis point.",
        "positive": "QED_3 on a space-time lattice: a comparison between compact and\n  noncompact formulation: Quantum electrodynamics in a (2+1)-dimensional space-time has been object of\nstudies both as effective theory for the pseudogap phase of high-T_c\nsuperconductors and for the theoretical investigation of mechanisms of\nconfinement in presence of matter fields. We discretize the theory using both\ncompact and noncompact formulations, analyze the behavior of the chiral\ncondensate and of the monopole density and compare them. Finally we draw some\nconclusions about the possible equivalence of the two lattice formulations."
    },
    {
        "anchor": "Impact of Dynamical Fermions on Centre Vortex Structure: This presentation examines the centre vortex structure of Monte-Carlo\ngenerated gauge-field configurations using modern visualisation techniques.\nThis time, the manner in which light dynamical fermion degrees of freedom\nimpact the centre-vortex structure is explored. Focusing on the thin vortices\nidentified by plaquettes having a non-trivial centre phase, the vortex\nstructure is illustrated through 3D renderings of oriented plaquettes. The\nimpact of light dynamical fermions is not subtle, changing both the density of\nvortices and the complexity of the vortex structures observed. The role of\nvortex branching points in full QCD is highlighted in the survey of results\npresented.",
        "positive": "Semi-leptonic form factors for $B_s \\to K \\ell \u03bd$ and $B_s \\to D_s\n  \\ell \u03bd$: Semi-leptonic $B_s \\to K \\ell \\nu$ and $B_s \\to D_s \\ell \\nu$ decays provide\nan alternative $b$-decay channel to determine the CKM matrix elements\n$|V_{ub}|$ and $|V_{cb}|$ or to obtain $R$-ratios to investigate lepton flavor\nuniversality violations. In addition, these decays may shed further light on\nthe discrepancies seen in the analysis of inclusive vs. exclusive decays. Using\nthe nonperturbative methods of lattice QCD, theoretical results are obtained\nwith good precision and full control over systematic uncertainties. This talk\nwill highlight ongoing efforts of the $B$-physics program by the RBC-UKQCD\ncollaboration."
    },
    {
        "anchor": "Matrix Elements of Light Quarks: Lattice results for matrix elements of light quark operators are reviewed.\nThe discussion is focused on recent theoretical progress and new numerical\ncalculations which appeared after the Lattice 2000 Conference.",
        "positive": "Non-compact QED_3 with N_f >=2: Non-compact three-dimensional QED is studied by computer simulations to\nunderstand its chiral symmetry breaking features for N_f>=2, on lattice volumes\nup to 50^3 and bare masses as low as ma=0.0000625. We compute the chiral\ncondensate, scalar and pseudoscalar susceptibilities, and the masses of scalar\nand pseudoscalar mesons. Finite volume effects and discretisation artifacts are\ncarefully monitored. Our results reveal no decisive signal for chiral symmetry\nbreaking for any N_f>=2. For N_f=2 the dimensionless condensate can be bounded\nby beta^2<psibarpsi> <= 5x10^-5. We also present an exploratory study of the\nfractionally-charged Polyakov line."
    },
    {
        "anchor": "Coupling the Deconfining and Chiral Transitions: The Polyakov loop and the chiral condensate are used as order parameters to\nexplore analytically the possible phase structure of finite temperature QCD.\nNambu-Jona-Lasinio models in a background temporal gauge field are combined\nwith a Polyakov loop potential in a form suitable for both the lattice and the\ncontinuum. Three possible behaviors are found: a first-order transition, a\nsecond-order transition, and a region with both transitions.",
        "positive": "Finite-representation approximation of lattice gauge theories at the\n  continuum limit with tensor networks: It has been established that Matrix Product States can be used to compute the\nground state and single-particle excitations and their properties of lattice\ngauge theories at the continuum limit. However, by construction, in this\nformalism the Hilbert space of the gauge fields is truncated to a finite number\nof irreducible representations of the gauge group. We investigate\nquantitatively the influence of the truncation of the infinite number of\nrepresentations in the Schwinger model, one-flavour QED$_2$, with a uniform\nelectric background field. We compute the two-site reduced density matrix of\nthe ground state and the weight of each of the representations. We find that\nthis weight decays exponentially with the quadratic Casimir invariant of the\nrepresentation which justifies the approach of truncating the Hilbert space of\nthe gauge fields. Finally, we compute the single-particle spectrum of the model\nas a function of the electric background field."
    },
    {
        "anchor": "Exploring distillation at the SU(3) flavour symmetric point: In these proceedings we present an exact distillation setup with stabilised\nWilson fermions at the SU(3) flavour symmetric point utilising the flexibility\nof the Grid and Hadrons software libraries. This work is a stepping stone\ntowards a non-perturbative investigation of hadronic D-decays, for which one\nneeds to control the multi-hadron final states. As a first step we study\ntwo-to-two s-wave scattering of pseudoscalar mesons. In particular we examine\nthe reliability of the extraction of finite-volume energies as a function of\nthe number of eigenvectors of the gauge-covariant Laplacian entering our\ndistillation setup.",
        "positive": "Microscopic universality with dynamical fermions: It has recently been demonstrated in quenched lattice simulations that the\ndistribution of the low-lying eigenvalues of the QCD Dirac operator is\nuniversal and described by random-matrix theory. We present first evidence that\nthis universality continues to hold in the presence of dynamical quarks. Data\nfrom a lattice simulation with gauge group SU(2) and dynamical staggered\nfermions are compared to the predictions of the chiral symplectic ensemble of\nrandom-matrix theory with massive dynamical quarks. Good agreement is found in\nthis exploratory study. We also discuss implications of our results."
    },
    {
        "anchor": "Phase Transition of 4D Simplicial Quantum Gravity with U(1) Gauge Field: The phase transition of 4D simplicial quantum gravity coupled to U(1) gauge\nfields is studied using Monte-Carlo simulations. The phase transition of the\ndynamical triangulation model with vector field ($N_{V}=1$) is smooth as\ncompared with the pure gravity($N_{V}=0$). The node susceptibility ($\\chi$) is\nstudied in the finite size scaling method. At the critical point, the node\ndistribution has a sharp peak in contrast to the double peak in the pure\ngravity. From the numerical results, we expect that 4D simplicial quantum\ngravity with U(1) vector fields has higher order phase transition than 1st\norder, which means the possibility to take the continuum limit at the critical\npoint.",
        "positive": "Static three- and four-quark potentials: We present results for the static three- and four-quark potentials in SU(3)\nand SU(4) respectively. Using a variational approach, combined with multi-hit\nfor the time-like links, we determine the ground state of the baryonic string\nwith sufficient accuracy to test the $Y-$ and $\\Delta-$ ans\\\"atze for the\nbaryonic Wilson area law. Our results favor the $\\Delta$ ansatz, where the\npotential is the sum of two-body terms."
    },
    {
        "anchor": "Moments of meson distribution functions with dynamical twisted mass\n  fermions: We present our preliminary results on the lowest moment <x> of quark\ndistribution functions of the pion using two flavor dynamical simulations with\nWilson twisted mass fermions at maximal twist. The calculation is done in a\nrange of pion masses from 300 to 500 MeV. A stochastic source method is used to\nreduce inversions in calculating propagators. Finite volume effects at the\nlowest quark mass are examined by using two different lattice volumes. Our\nresults show that we achieve statistical errors of only a few percent. We plan\nto compute renormalization constants non-perturbatively and extend the\ncalculation to two more lattice spacings and to the nucleons.",
        "positive": "AdS/CFT Correspondence in Hyperbolic Lattices: The AdS/CFT correspondence, also known as the gravity/gauge duality, posits a\ndual relationship between the theory of gravity in Anti-de Sitter (AdS) space\nand conformal field theory (CFT) defined on its lower-dimensional boundary.\nThis correspondence provides a means of mapping problems from one theory to the\nother, offering insights into quantum gravity and quantum field theory. Despite\nits importance in contemporary physics, the AdS/CFT correspondence remains a\nconjecture, and further experimental investigation is highly sought after.\nHere, we experimentally explore the AdS/CFT correspondence in both conventional\ntype-I and previously overlooked type-II hyperbolic lattices, as the\ndiscretized regularizations of spatial geometries of pure AdS2+1 spacetime and\nAdS2+1 black hole. Using time-resolved and pump-prob measurements, we identify\ndistinct geodesic behaviors in the absence or presence of an analogue black\nhole. Moreover, we experimentally confirm two pivotal theoretical predictions\nof the AdS/CFT correspondence: the Ryu-Takayanagi (RT) formula that\ncharacterizes the entanglement entropy of the boundary CFT2 through the minimal\ngeodesic in the spatial section of bulk AdS2+1, and the exponential dependence\nof the boundary-boundary two-point correlation function on the hyperbolic\ndistance which determines the conformal dimension of the boundary CFT1\nassociated with the scalar field mass in the bulk Euclidean AdS2 (EAdS2). This\ninitial experimental effort opens a new avenue for future investigation on the\ngravity/gauge duality and the exploration of quantum-gravity-inspired phenomena\nin classical systems."
    },
    {
        "anchor": "SU(2) potentials in quantum gravity: We present investigations of the potential between static charges from a\nsimulation of quantum gravity coupled to an SU(2) gauge field on $6^{3}\\times\n4$ and $8^{3}\\times 4$ simplicial lattices. In the well-defined phase of the\ngravity sector where geometrical expectation values are stable, we study the\ncorrelations of Polyakov loops and extract the corresponding potentials between\na source and sink separated by a distance $R$. In the confined phase, the\npotential has a linear form while in the deconfined phase, a screened Coulombic\nbehavior is found. Our results indicate that quantum gravitational effects do\nnot destroy confinement due to non-abelian gauge fields.",
        "positive": "Atiyah-Patodi-Singer index on a lattice: We propose a non-perturbative formulation of the Atiyah-Patodi-Singer(APS)\nindex in lattice gauge theory, in which the index is given by the $\\eta$\ninvariant of the domain-wall Dirac operator. Our definition of the index is\nalways an integer with a finite lattice spacing. To verify this proposal, using\nthe eigenmode set of the free domain-wall fermion, we perturbatively show in\nthe continuum limit that the curvature term in the APS theorem appears as the\ncontribution from the massive bulk extended modes, while the boundary $\\eta$\ninvariant comes entirely from the massless edge-localized modes."
    },
    {
        "anchor": "Effects of dynamical sea-quarks on quark and gluon propagators: We present an unquenched calculation of the quark propagator in Landau gauge\nwith 2+1 flavors of dynamical quarks. We study the scaling behavior of the\nquark propagator in full QCD on two lattices with different lattice spacings\nand similar physical volume. We use configurations generated with an improved\nstaggered (``Asqtad'') action by the MILC collaboration.",
        "positive": "Charmonium spectroscopy from an anisotropic lattice study: We present a progress report on our study of the charmonium spectrum in full\nQCD on anisotropic lattices generated by the Hadron Spectrum Collaboration. We\nadopt a large basis of interpolating operators to extract the excited\ncharmonium states using the variational method. A detailed spectrum of excited\ncharmonium mesons in many $J^{PC}$ channels is obtained. Hybrid states with\nexotic and non-exotic quantum numbers are determined and preliminary results\nfrom a study of disconnected contributions to the $\\eta_c$ are presented."
    },
    {
        "anchor": "Speeding up the HMC algorithm: Some new results: We give some new performance results for the Hybrid Monte Carlo (HMC)\nsimulation of dynamical clover-improved Wilson fermions using an improved\npseudo-fermion action. The generalisation of even-odd preconditioning for the\nstandard Wilson fermion matrix to the clover-improved case is not unique. In\nthe literature the so called symmetric and asymmetric versions are discussed.\nMost of the previous simulations of dynamical clover-improved Wilson fermions\nwere done with the asymmetric version. Only recently, the JLQCD collaboration\nhas pointed out that the symmetric version leads to a better performance of the\nHMC algorithm. Here, we show that also in combination with an improved\npseudo-fermion action, the symmetric version of even-odd preconditioning leads\nto a better performance. For our lightest quark mass, which corresponds to\n$m_{PS}/m_{V} \\approx 0.44$, we see a gain in performance by a factor of about\n1.3.",
        "positive": "Landau levels in QCD in an external magnetic field: We will discuss the issue of Landau levels of quarks in lattice QCD in an\nexternal magnetic field. We will show that in the two-dimensional case the\nlowest Landau level can be identified unambiguously even if the strong\ninteractions are turned on. Starting from this observation, we will then show\nhow one can define a \"lowest Landau level\" in the four-dimensional case, and\ndiscuss how much of the observed effects of a magnetic field can be explained\nin terms of it. Our results can be used to test the validity of low-energy\nmodels of QCD that make use of the lowest-Landau-level approximation."
    },
    {
        "anchor": "Phenomenology with Wilson fermions using smeared sources: We investigate the use of two types of non-local (``smeared'') sources for\nquark propagators in quenched lattice QCD at $\\beta=6.0$ using Wilson fermions\nat $\\kappa=0.154$ and $0.155$. We present results for the hadron mass spectrum,\nmeson decay constants, quark masses, the chiral condensate and the quark\ndistribution amplitude of the pion. The use of smeared sources leads to a\nconsiderable improvement over previous results. We find a disturbing\ndiscrepancy between the baryon spectra obtained using Wuppertal and wall\nsources. We find good signals in the ratio of correlators used to calculate the\nquark mass and the chiral condensate and show that the extrapolation to the\nchiral limit is smooth.",
        "positive": "Center vortex model for nonperturbative strong interaction physics: A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic\nvortex degrees of freedom represented by (closed) random world-surfaces, is\npresented. The model quantitatively describes both the confinement properties\n(including the finite-temperature transition to a deconfined phase) and the\ntopological susceptibility of the Yang-Mills ensemble. A (quenched) study of\nthe spectrum of the Dirac operator furthermore yields a behavior for the chiral\ncondensate which is compatible with results obtained in lattice gauge theory."
    },
    {
        "anchor": "Stochastic normalizing flows for lattice field theory: Stochastic normalizing flows are a class of deep generative models that\ncombine normalizing flows with Monte Carlo updates and can be used in lattice\nfield theory to sample from Boltzmann distributions. In this proceeding, we\noutline the construction of these hybrid algorithms, pointing out that the\ntheoretical background can be related to Jarzynski's equality, a\nnon-equilibrium statistical mechanics theorem that has been successfully used\nto compute free energy in lattice field theory. We conclude with examples of\napplications to the two-dimensional $\\phi^4$ field theory.",
        "positive": "A comment on the index of the lattice Dirac operator and the\n  Ginsparg-Wilson relation: We pursue Ginsparg and Wilsons' block spin approach in the derivation of the\nGinsparg-Wilson relation and study the correspondence of the eigenmodes of the\nDirac operators in the continuum and lattice theories. After introducing a\nsuitable cut-off in the continuum theory, we identify unphysical modes of the\nlattice Dirac operator which do not correspond to any physical modes of the\nregulated continuum Dirac operator. We also consider zero modes in the\ncontinuum and lattice theories. Our studies give a physical interpretation of\nthe expression of the index defined on a lattice and a formal argument on the\nrelation of the indices between the continuum and lattice theories."
    },
    {
        "anchor": "Recent developments in chiral gauge theories: Approach of infinitely\n  many fermi fields: I present the recent developments in a specific sub-field of chiral gauge\ntheories on the lattice. This sub-field pertains to the use of infinitely many\nfermi fields to describe a single chiral field. In this approach, both\nanomalous and anomaly free theories can be discussed in equal footing. It\nproduces the correct anomaly in the continuum limit. It has the potential to\ndescribe fermion number violating processes in the presence of a gauge field\nbackground with non-trivial topological charge on a finite lattice.",
        "positive": "O(4) scaling analysis in two-flavor QCD at finite temperature and\n  density with improved Wilson quarks: We study the curvature of the chiral transition/crossover line between the\nlow-temperature hadronic phase and the high-temperature quark-gluon-plasma\nphase at low densities, performing simulations of two-flavor QCD with improved\nWilson quarks. After confirming that the chiral order parameter defined by a\nWard-Takahashi identity is consistent with the scaling of the O(4) universality\nclass at zero chemical potential, we extend the scaling analysis to finite\nchemical potential to determine the curvature of the chiral\ntransition/crossover line at low densities assuming the O(4) universality. To\nconvert the curvature in lattice units to that of the $T_c(\\mu_B)$ in physical\nunits, we evaluate the lattice scale applying a gradient flow method. We find\n$\\kappa=0.0006(1)$ in the chiral limit, which is much smaller than that\nobtained in (2+1)-flavor QCD with improved staggered quarks."
    },
    {
        "anchor": "Grand canonical potential for a static quark--anti-quark pair at finite\n  T/mu: We present numerical results on the static quark--anti-quark grand canonical\npotential in full QCD at non-vanishing temperature ($T$) and quark chemical\npotential ($\\mu$). Non-zero $\\mu$-s are reached by means of multi-parameter\nreweighting. The dynamical staggered simulations were carried out for $n_f=2+1$\nflavors with physical quark masses on $4\\times 12^3$ lattices.",
        "positive": "Scattering phase shifts for two particles of different mass and non-zero\n  total momentum in lattice QCD: We derive the relation between the scattering phase shift and the\ntwo-particle energy in the finite box, which is relevant for extracting the\nstrong phase shifts in lattice QCD. We consider elastic scattering of two\nparticles with different mass and with non-zero total momentum in the lattice\nframe. This is a generalization of the Luscher formula, which considers zero\ntotal momentum, and the generalization of Rummukainen-Gottlieb's formula, which\nconsiders degenerate particles with non-zero total momentum. We focus on the\nmost relevant total momenta in practice, i.e. P=(2\\pi/L) e_z and P=(2\\pi/L)\n(e_x+e_y) including their multiples and permutations. We find that the P-wave\nphase shift can be reliably extracted from the two-particle energy if the phase\nshifts for l>=2 can be neglected, and we present the corresponding relations.\nThe reliable extraction of S-wave phase shift is much more challenging since\ndelta(l=0) is always accompanied by delta(l=1) in the phase shift relations,\nand we propose strategies for estimating delta(l=0). We also propose the\nquark-antiquark and meson-meson interpolators that transform according the\nconsidered irreducible representations."
    },
    {
        "anchor": "Quantifying corrections to the hadron resonance gas with lattice QCD: The hadron resonance gas (HRG) model and its extensions are often used to\ndescribe the hadronic phase of strongly interacting matter. In our work we use\nlattice-QCD simulations with temporal extents of $N_\\tau=8,10$ and $12$ to\nquantify corrections to the ideal HRG. Firstly, we determine a number of\nsubleading fugacity expansion coefficients of the QCD free energy via a\ntwo-dimensional scan on the imaginary baryon number chemical potential\n($\\mu_B$) - strangeness chemical potential ($\\mu_S$) plane. Using the\naforementioned coefficients, we also extrapolate ratios of baryon number and\nstrangeness fluctuations and correlations to finite chemical potentials via a\ntruncated fugacity expansion. Our results extrapolated along the crossover line\n$T_\\mathrm{c}(\\mu_B)$ at strangeness neutrality are able to reproduce trends of\nexperimental net-proton fluctuations measured by the STAR Collaboration.",
        "positive": "Recent results in high temperature lattice gauge theories: We review some analytic results on the deconfinement transition in pure\nlattice gauge theories. In particular we discuss the relationship between the\ndeconfinement transition in the $(d+1)$-dimensional $SU(2)$ model and the\nmagnetization transition in the $d$-dimensional Ising model. This analysis\nleads to a precise estimate of the deconfinement temperature which agrees well\nwith that obtained with a Montecarlo simulation in the case in which the\nlattice has only one link in the compactified time direction."
    },
    {
        "anchor": "A Worm Algorithm for the Lattice CP(N-1) Model: The CP(N-1) model in 2D is an interesting toy model for 4D QCD as it\npossesses confinement, asymptotic freedom and a non-trivial vacuum structure.\nDue to the lower dimensionality and the absence of fermions, the computational\ncost for simulating 2D CP(N-1) on the lattice is much lower than the one for\nsimulating 4D QCD. However to our knowledge, no efficient algorithm for\nsimulating the lattice CP(N-1) model has been tested so far, which also works\nat finite density. To this end we propose and test a new type of worm algorithm\nwhich is appropriate to simulate the lattice CP(N-1) model in a dual,\nflux-variables based representation, in which the introduction of a chemical\npotential does not give rise to any complications.",
        "positive": "Chiral Aspects of Improved Staggered Fermions with 2+1-Flavors from the\n  HotQCD Collaboration: We present recent results from lattice simulations of 2+1 flavors of improved\nstaggered fermions at zero baryon number density near the high temperature\ncrossover. Included are new results from simulations of asqtad fermions at Nt =\n12 and a nearly physical Goldstone pion mass and from simulations of HISQ\nfermions at Nt = 6 and 8. We focus on observables sensitive to chiral symmetry\nand confinement. A companion HotQCD talk discusses the effects of\nstaggered-fermion taste-symmetry breaking on thermodynamic quantities."
    },
    {
        "anchor": "The spin content of the proton in quenched QCD: We present preliminary results on the proton spin structure function at zero\nmomentum, in the quenched approximation. Our calculation makes use of a\nnonperturbative means of determining the multiplicative renormalization of the\ntopological charge density.",
        "positive": "Beta function of three-dimensional QED: We have carried out a Schrodinger-functional calculation for the Abelian\ngauge theory with Nf=2 four-component fermions in three dimensions. We find no\nfixed point in the beta function, meaning that the theory is confining rather\nthan conformal."
    },
    {
        "anchor": "Investigating how to simulate lattice gauge theories on a quantum\n  computer: Quantum computers have the potential to expand the utility of lattice gauge\ntheory to investigate non-perturbative particle physics phenomena that cannot\nbe accessed using a standard Monte Carlo method due to the sign problem. Thanks\nto the qubit, quantum computers can store Hilbert space in a more efficient way\ncompared to classical computers. This allows the Hamiltonian approach to be\ncomputationally feasible, leading to absolute freedom from the sign-problem.\nBut what the current noisy intermediate scale quantum hardware can achieve is\nunder investigation, and therefore we chose to study the energy spectrum and\nthe time evolution of an SU(2) theory using two kinds of quantum hardware: the\nD-Wave quantum annealer and the IBM gate-based quantum hardware.",
        "positive": "Ab Initio Calculation of Finite Temperature Charmonium Potentials: The interquark potential in charmonium states is calculated for the first\ntime in both the zero and non-zero temperature phases from a first-principles\nlattice QCD calculation. Simulations with two dynamical quark flavours were\nused with temperatures T in the range 0.4 T_c \\lesssim T \\lesssim 1.7 T_c,\nwhere T_c is the deconfining temperature. The correlators of point-split\noperators were analysed to gain spatial information about the charmonium\nstates. A method, introduced by the HAL QCD collaboration and based on the\nSchroedinger equation, was applied to obtain the interquark potential. We find\na clear temperature dependence, with the central potential becoming flatter\n(more screened) as the temperature increases."
    },
    {
        "anchor": "$\u0394I = 3/2$ kaon weak matrix elements with non-zero total momentum: We present preliminary results for the $\\Delta I = 3/2$ kaon decay matrix\nelements using domain wall fermions and the DBW2 gauge action at one coarse\nlattice spacing corresponding to $a^{-1} = 1.3$ GeV. We employ an extention of\nthe Lellouch and L\\\"uscher formula for non-zero total momentum to extract the\ninfinite volume, center-of-mass system decay amplitudes. We compare the result\nof $\\mathrm{Re}A_2$ with previous results calculated by several methods, and\nexperiment. We also show the I=2 $\\pi\\pi$ scattering phase shift.",
        "positive": "Center Projection With and Without Gauge Fixing: We consider projections of SU(2) lattice link variables onto Z(2) center and\nU(1) subgroups, with and without gauge-fixing. It is shown that in the absence\nof gauge-fixing, and up to an additive constant, the static quark potential\nextracted from projected variables agrees exactly with the static quark\npotential taken from the full link variables; this is an extension of recent\narguments by Ambjorn and Greensite, and by Ogilvie. Abelian and center\ndominance is essentially trivial in this case, and seems of no physical\nrelevance. The situation changes drastically upon gauge fixing. In the case of\ncenter projection, there are a series of tests one can carry out, to check if\nvortices identified in the projected configurations are physical objects. All\nthese criteria are satisfied in maximal center gauge, and we show here that\nthey all fail in the absence of gauge fixing. The non-triviality of center\nprojection is due entirely to the maximal center gauge-fixing, which pumps\ninformation about the location of extended physical objects into local Z(2)\nobservables."
    },
    {
        "anchor": "Rooted staggered fermions: good, bad or ugly?: I give a status report on the validity of the so-called ``fourth-root\ntrick'', i.e. the procedure of representing the determinant for a single\nfermion by the fourth root of the staggered fermion determinant. This has been\nused by the MILC collaboration to create a large ensemble of lattices using\nwhich many quantities of physical interest have been and are being calculated.\nIt is also used extensively in studies of QCD thermodynamics. The main question\nis whether the theory so defined has the correct continuum limit. There has\nbeen significant recent progress towards answering this question. After\nrecalling the issue, and putting it into a broader context of results from\nstatistical mechanics, I critically review the new work. I also address the\nrelated issue of the impact of treating valence and sea quarks differently in\nrooted simulations, discuss whether rooted simulations at finite temperature\nand density are subject to additional concerns, and briefly update results for\nquark masses using the MILC configurations. An answer to the question in the\ntitle is proposed in the summary.",
        "positive": "Non-perturbatively determined relativistic heavy quark action: Preliminary results are presented in a step scaling determination of the\ncoefficients in the relativistic heavy quark action. By matching finite volume,\nheavy-heavy and heavy-light meson masses, we attempt to determine the four\nparameters ($m$, $\\zeta$, $c_B$ and $c_E$) in the on-shell-improved, heavy\nquark action. In this report we carry out one step in this program by matching\ntwo physically equivalent systems. The first is a fully relativistic\ncalculation using a $24^3\\times 48$, $1/a=5.4$ GeV lattice with both the heavy\nand light quarks treated as domain wall fermions. The second calculation uses\nat $16^3\\times 32$, $1/a=3.6$ GeV lattice, a domain-wall light quark and a\nheavy quark computed with the relativistic heavy quark action. The four\nparameters in this heavy quark effective action are then varied to reproduce\nthe mass spectrum from the first calculation. These calculations are carried\nout in the quenched approximation for a heavy quark mass approximately that of\nthe charmed quark."
    },
    {
        "anchor": "Bethe-Salpeter Amplitudes and Density Correlations for Mesons with\n  Wilson Fermions: We present an investigation of various gauge invariant definitions of the\n$q\\bar q$ Bethe-Salpeter (BS) amplitude for mesons in lattice QCD, and compare\nthem to the Coulomb and Landau gauge BS amplitudes. We show that the gauge\ninvariant BS amplitude is considerably broadened by the use of ``fat'' gauge\nlinks (constructed by smearing the links of the original lattice). A\nqualitative demonstration of the Lorentz contraction of the pion wavefunction\nat non-zero momentum is given. We also calculate density-density correlations\nand discuss the limitations in extracting the charge radius of the pion from\nthese observables. Lastly, the polarization dependence of the BS amplitude for\nthe $\\rho$ meson is exhibited, and we extract the relative admixture of $l=0$\nand $l=2$ states showing that simple hydrogen-like wavefunctions provide a good\nfit.",
        "positive": "Lattice simulations with eight flavors of domain wall fermions in SU(3)\n  gauge theory: We study an SU(3) gauge theory with Nf=8 degenerate flavors of light fermions\nin the fundamental representation. Using the domain wall fermion formulation,\nwe investigate the light hadron spectrum, chiral condensate and electroweak S\nparameter. We consider a range of light fermion masses on two lattice volumes\nat a single gauge coupling chosen so that IR scales approximately match those\nfrom our previous studies of the two- and six-flavor systems. Our results for\nthe Nf=8 spectrum suggest spontaneous chiral symmetry breaking, though fits to\nthe fermion mass dependence of spectral quantities do not strongly disfavor the\nhypothesis of mass-deformed infrared conformality. Compared to Nf=2 we observe\na significant enhancement of the chiral condensate relative to the symmetry\nbreaking scale F, similar to the situation for Nf=6. The reduction of the S\nparameter, related to parity doubling in the vector and axial-vector channels,\nis also comparable to our six-flavor results."
    },
    {
        "anchor": "eta' meson From Two Flavor Dynamical Domain Wall Fermions: We explore flavor singlet pseudoscalar meson, eta', spectrum in two-flavor\n(Nf=2) lattice QCD. The continuum-like relation between the topology of the QCD\nvacuum and the U(1)_A anomaly, that prevents eta' meson from being a would-be\nNambu-Goldstone boson, are expected to hold in the domain wall fermions (DWF)\nused as a lattice quark field in this work. Although our simulation is limited\nto relatively heavy quark masses and statistical error is not magnificently\nsmall despite of improvements in measurements and fit procedures for meson\npropagators, we obtained m_eta'=819(127) MeV for Nf=2 QCD, where the error is\nstatistical only. Potentially serious systematic error in the number are\ndiscussed. Results for other meson are also reported.",
        "positive": "Update on pi and K Physics: We present an update of the MILC studies of the physics of light\npseudoscalars using improved staggered fermions. New runs at lighter quark\nmass, as well as increased statistics for older sets, are enabling us to\nimprove the results for decay constants in full QCD. In addition, we have\nanalyzed quenched runs at two different lattice spacings. This makes possible a\ntest of the applicability of staggered chiral perturbation theory in a\ndifferent context."
    },
    {
        "anchor": "D-branes, Wilson Bags, and Coherent Topological Charge Structure in QCD: Monte Carlo studies of pure glue SU(3) gauge theory using the overlap-based\ntopological charge operator have revealed a laminar structure in the QCD vacuum\nconsisting of extended, thin, coherent, locally 3-dimensional sheets of\ntopological charge embedded in 4D space, with opposite sign sheets interleaved.\nStudies of localization properties of Dirac eigenmodes have also shown evidence\nfor the delocalization of low-lying modes on effectively 3-dimensional\nsurfaces. In this talk, I review some theoretical ideas which suggest the\npossibility of 3-dimensionally coherent topological charge structure in\n4-dimensional gauge theory and provide a possible interpretation of the\nobserved structure. I begin with Luscher's ``Wilson bag'' integral over the\n3-index Chern-Simons tensor. The analogy with a Wilson loop as a charged world\nline in 2-dimensional $CP^{N-1}$ sigma models suggests that the Wilson bag\nsurface represents the world volume of a physical membrane. The large-N chiral\nLagrangian arguments of Witten also indicate the existence of multiple\n``k-vacuum'' states with discontinuous transitions between k-vacua at $\\theta=$\nodd multiples of $\\pi$. The domain walls between these vacua have the\nproperties of a Wilson bag surface. Finally, I review the AdS/CFT duality view\nof $\\theta$ dependence in QCD. The dual realtionship between topological charge\nin gauge theory and Ramond-Ramond charge in type IIA string theory suggests\nthat the coherent topological charge sheets observed on the lattice are the\nholographic image of wrapped D6 branes.",
        "positive": "The Kramers equation simulation algorithm II. An application to the\n  Gross-Neveu model: We continue the investigation on the applications of the Kramers equation to\nthe numerical simulation of field theoretic models. In a previous paper we have\ndescribed the theory and proposed various algorithms. Here, we compare the\nsimplest of them with the Hybrid Monte Carlo algorithm studying the\ntwo-dimensional lattice Gross-Neveu model. We used a Symanzik improved action\nwith dynamical Wilson fermions. Both the algorithms allow for the determination\nof the critical mass. Their performances in the definite phase simulations are\ncomparable with the Hybrid Monte Carlo. For the two methods, the numerical\nvalues of the measured quantities agree within the errors and are compatible\nwith the theoretical predictions; moreover, the Kramers algorithm is safer from\nthe point of view of the numerical precision."
    },
    {
        "anchor": "Atomic Bose Condensation and the Lattice: I show how interaction corrections to the Bose condensation temperature of an\natomic gas can be computed using a combination of perturbative effective field\ntheory and lattice techniques.",
        "positive": "H-Dibaryon from Lattice QCD with Improved Anisotropic Actions: The six quark state(uuddss) called H dibaryon($J^P=0^+$,$S=-2$) has been\ncalculated to study its existence and stability. The simulations are performed\nin quenched QCD on $8^3 \\times 24$ and $16^3 \\times 48$ anisotropic lattices\nwith Symanzik improved gauge action and Clover fermion action. The gauge\ncoupling is $\\beta=2.0$ and aspect ratio $\\xi=a_s/a_t=3.0$. Preliminary results\nindicate that mass of H dibaryon is 2134(100)Mev on $8^3 \\times 24$ lattice and\n2167(59)Mev on $16^3 \\times 48$ respectively. It seems that the radius of H\ndibaryon is very large and the finite size effect is very obvious."
    },
    {
        "anchor": "The QCD rotator with a light quark mass: The low-lying energy excitations of 2-flavour QCD in the chiral limit\nconfined to a small spatial box ($\\delta$-regime) are that of an $O(4)$\nrotator. In this work, we calculate the corrections due to the presence of a\nnonzero quark mass up to NNL order by means of dimensional regularised chiral\nperturbation theory. The final result for the energy gap of the system only\ninvolves the low-energy constants $F$, $\\Lambda_1$, $\\Lambda_2$ and $B$.",
        "positive": "Making QCD Lattice Data Accessible and Organized through Advanced Web\n  Interfaces: The Gauge Connection at qcd.nersc.gov is one of the most popular repositories\nof QCD lattice ensembles. It is used to access 16TB of archived QCD data from\nthe High Performance Storage System (HPSS) at the National Energy Research\nScientific Computing Center (NERSC). Here, we present a new web interface for\nqcd.nersc.gov which allows physicists to browse and search the data, as well as\ndownload individual files or entire ensembles in batch. Our system\ndistinguishes itself from others because of its ease of use and web based\nworkflow."
    },
    {
        "anchor": "The Spin Content of the Nucleon: The fraction of the nucleon spin that is carried by the quarks, $\\Delta\n\\Sigma$, is computed in lattice QCD with dynamical staggered fermions. We\nobtain the value $\\Delta \\Sigma = 0.18 \\pm 0.02$.",
        "positive": "Hypercubic Effects in semileptonic $D \\to \u03c0$ decays on the lattice: We present a lattice determination of the vector and scalar form factors of\nthe semileptonic $D \\to \\pi \\ell \\nu$ decays, which are relevant for the\nextraction of the CKM matrix element $\\lvert V_{cd} \\rvert$ from experimental\ndata. Our analysis is based on the gauge configurations produced by the\nEuropean Twisted Mass Collaboration with $N_f = 2 + 1 + 1$ flavors of dynamical\nquarks. We simulated at three different values of the lattice spacing and with\npion masses as small as 210 MeV. Quark momenta are injected on the lattice\nusing non-periodic boundary conditions. The matrix elements of both vector and\nscalar currents are determined for a plenty of kinematical conditions in which\nparent and child mesons are either moving or at rest. Lorentz symmetry breaking\ndue to hypercubic effects is clearly observed in the data and included in the\ndecomposition of the current matrix elements in terms of additional form\nfactors. Our preliminary estimate for the vector form factor at zero 4-momentum\ntransfer is $f_+^{D \\to \\pi}(0) = 0.631\\,(40)$, which can be compared with the\nlatest FLAG average $f_+^{D \\to \\pi}(0) = 0.666\\,(29)$ available only at $N_f =\n2 + 1$."
    },
    {
        "anchor": "Critical analysis of topological charge determination in the background\n  of center vortices in SU(2) lattice gauge theory: We analyze topological charge contributions from classical SU(2) center\nvortices with shapes of planes and spheres using different topological charge\ndefinitions, namely the center vortex picture of topological charge, a discrete\nversion of F\\~{F} in the plaquette and hypercube definitions and the lattice\nindex theorem. For the latter the zeromodes of the Dirac operator in the\nfundamental and adjoint representations using both the overlap and asqtad\nstaggered fermion formulations are investigated. We find several problems for\nthe individual definitions and discuss the discrepancies between the different\ntopological charge definitions. Our results show that the interpretation of\ntopological charge in the background of center vortices is rather subtle.",
        "positive": "Thermal field theories and shifted boundary conditions: The analytic continuation to an imaginary velocity of the canonical partition\nfunction of a thermal system expressed in a moving frame has a natural\nimplementation in the Euclidean path-integral formulation in terms of shifted\nboundary conditions. The Poincare' invariance underlying a relativistic theory\nimplies a dependence of the free-energy on the compact length L_0 and the shift\nxi only through the combination beta=L_0(1+xi^2)^(1/2). This in turn implies\nthat the energy and the momentum distributions of the thermal theory are\nrelated, a fact which is encoded in a set of Ward identities among the\ncorrelators of the energy-momentum tensor. The latter have interesting\napplications in lattice field theory: they offer novel ways to compute\nthermodynamic potentials, and a set of identities to renormalize\nnon-perturbatively the energy-momentum tensor. At fixed bare parameters the\nshifted boundary conditions also provide a simple method to vary the\ntemperature in much smaller steps than with the standard procedure."
    },
    {
        "anchor": "$N\u03c0$-state contamination in lattice calculations of the nucleon\n  electromagnetic form factors: The nucleon-pion-state contribution to QCD two-point and three-point\nfunctions relevant for lattice calculations of the nucleon electromagnetic form\nfactors are studied in chiral perturbation theory. To leading order the results\ndepend on a few experimentally known low-energy constants only, and the\nnucleon-pion-state contribution to the form factors can be estimated. The\nnucleon-pion-state contribution to the electric form factor $G_{\\rm E}(Q^2)$ is\nat the +5 percent level for a source-sink separation of 2 fm, and it increases\nwith increasing momentum transfer $Q^2$. For the magnetic form factor the\nnucleon-pion-state contribution leads to an underestimation of $G_{\\rm M}(Q^2)$\nby about 5 percent that decreases with increasing $Q^2$. For smaller\nsource-sink separations that are accessible in present-day lattice simulations\nthe impact is larger, although the ChPT results may not be applicable for such\nsmall time separations. Still, a comparison with lattice data at $t\\approx 1.6$\nfm works reasonably well.",
        "positive": "Lattice QCD with dynamical domain wall quarks: We study lattice QCD with two flavors of dynamical domain wall quarks. With\nrenormalization group motivated actions, we find chiral symmetry can be\npreserved to a high degree at lattice cut off of a^{-1} \\sim 2 GeV even for\nfifth dimension size as small as L_s = 12. In addition two new steps are\nintroduced to improve the performance of the hybrid Monte Carlo simulation."
    },
    {
        "anchor": "Validity of the Rooted Staggered Determinant in the continuum limit: We investigate the continuum limit of the rooted staggered determinant in the\n2-dimensional Schwinger model. We match both the unrooted and rooted staggered\ndeterminant with an overlap fermion determinant of two (one) flavors and a\nlocal pure gauge effective action by fitting the coefficients of the effective\naction and the mass of the overlap operator. The residue of this fit measures\nthe difference of the staggered and overlap fermion actions. We show that this\nresidue scales at least as O(a^2), implying that any difference, be it local or\nnon-local, between the staggered and overlap actions becomes irrelevant in the\ncontinuum limit. This observation justifies the rooting procedure.",
        "positive": "B Meson Decay Constants From NRQCD: We present quenched results for B meson decay constants using NRQCD b quarks\nand O(a) tadpole improved clover light quarks. For the first time, one-loop\nmatching factors between lattice and continuum currents are incorporated\nthrough O(\\alpha/M) taking operator mixing fully into account. This includes an\nimportant O(\\alpha a) discretization correction to the heavy-light axial vector\ncurrent. We find f_B = 0.147(11)(^{+8}_{-12})(9)(6) MeV and f_{B_s}/f_B =\n1.20(4)(^{+4}_{-0}).\n  PACS numbers: 12.38.Gc, 12.39.Hg, 13.20.He, 14.40.Nd"
    },
    {
        "anchor": "Quark-Gluon Mixed Condensate (anti-Q sigma G Q) from Lattice QCD: We study the quark-gluon mixed condensate g<\\bar{q} sigma G q>, which is\nanother chiral order parameter, in SU(3)c lattice QCD with the Kogut-Susskind\nfermion at the quenched level. Using 100 gauge configurations on the 16^4\nlattice with \\beta = 6.0, we measure the mixed condensate at 16 points in each\ngauge configuration for each current-quark mass of m_q=21, 36, 52 MeV. From the\n1600 data for each m_q, we find the ratio between the mixed condensate and the\nquark condensate, m_0^2 = g<\\bar{q} sigma G q> / <\\bar{q}q> \\simeq 2.5 GeV^2 at\nthe lattice scale of 1/a \\simeq 2 GeV in the chiral limit. The large value of\nthe mixed condensate suggests its importance in the operator product expansions\nin QCD. We also show our preliminary results of the mixed condensate at finite\ntemperature.",
        "positive": "Cost of dynamical quark simulations with improved staggered quarks: The cost of dynamical quark simulations with improved staggered quarks is\nestimated based on current and planned running by the MILC collaboration. I\nfind that a few 10s of Teraflop years should be sufficient to calculate down to\na lattice spacing of 0.045 fm."
    },
    {
        "anchor": "Neural-network preconditioners for solving the Dirac equation in lattice\n  gauge theory: This work develops neural-network--based preconditioners to accelerate\nsolution of the Wilson-Dirac normal equation in lattice quantum field theories.\nThe approach is implemented for the two-flavor lattice Schwinger model near the\ncritical point. In this system, neural-network preconditioners are found to\naccelerate the convergence of the conjugate gradient solver compared with the\nsolution of unpreconditioned systems or those preconditioned with conventional\napproaches based on even-odd or incomplete Cholesky decompositions, as measured\nby reductions in the number of iterations and/or complex operations required\nfor convergence. It is also shown that a preconditioner trained on ensembles\nwith small lattice volumes can be used to construct preconditioners for\nensembles with many times larger lattice volumes, with minimal degradation of\nperformance. This volume-transferring technique amortizes the training cost and\npresents a pathway towards scaling such preconditioners to lattice field theory\ncalculations with larger lattice volumes and in four dimensions.",
        "positive": "Leutwyler-Smilga sum rules for Ginsparg-Wilson lattice fermions: We argue that lattice QCD with Ginsparg-Wilson fermions satisfies the\nLeutwyler-Smilga sum rules for the eigenvalues of the chiral Dirac operator.\nThe result is obtained in the one flavor case, by rephrasing Leutwyler and\nSmilga's original analysis for the finite volume partition function. This is a\nfurther evidence that Ginsparg-Wilson fermions, even if breaking explicitly the\nchirality on the lattice in accordance to the Nielsen-Ninomiya theorem, mimic\nthe main features of the continuum theory related to chiral symmetry."
    },
    {
        "anchor": "Testing a non-perturbative mechanism for elementary fermion mass\n  generation: lattice setup: In this contribution we lay down a lattice setup that allows for the\nnon-perturbative study of a field theoretical model where a SU(2) fermion\ndoublet, subjected to non-Abelian gauge interactions, is also coupled to a\ncomplex scalar field doublet via a Yukawa and an \"irrelevant\" Wilson-like term.\nUsing naive fermions in quenched approximation and based on the renormalized\nWard identities induced by purely fermionic chiral transformations, lattice\nobservables are discussed that enable: a) in the Wigner phase, the\ndeterminations of the critical Yukawa coupling value where the purely fermionic\nchiral transformation become a symmetry up to lattice artifacts; b) in the\nNambu-Goldstone phase of the resulting critical theory, a stringent test of the\nactual generation of a fermion mass term of non-perturbative origin. A soft\ntwisted fermion mass term is introduced to circumvent the problem of\nexceptional configurations, and observables are then calculated in the limit of\nvanishing twisted mass.",
        "positive": "Complex Langevin Dynamics for chiral Random Matrix Theory: We apply complex Langevin dynamics to chiral random matrix theory at nonzero\nchemical potential. At large quark mass the simulations agree with the\nanalytical results while incorrect convergence is found for small quark masses.\nThe region of quark masses for which the complex Langevin dynamics converges\nincorrectly is identified as the region where the fermion determinant\nfrequently traces out a path surrounding the origin of the complex plane during\nthe Langevin flow. This links the incorrect convergence to an ambiguity in the\nLangevin force due to the presence of the logarithm of the fermion determinant\nin the action."
    },
    {
        "anchor": "Scaling, asymptotic scaling and Symanzik improvement. Deconfinement\n  temperature in SU(2) pure gauge theory: We report on a high statistics simulation of SU(2) pure gauge field theory at\nfinite temperature, using Symanzik action. We determine the critical coupling\nfor the deconfinement phase transition on lattices up to 8 x 24, using Finite\nSize Scaling techniques. We find that the pattern of asymptotic scaling\nviolation is essentially the same as the one observed with conventional, not\nimproved action. On the other hand, the use of effective couplings defined in\nterms of plaquette expectation values shows a precocious scaling, with respect\nto an analogous analysis of data obtained by the use of Wilson action, which we\ninterpret as an effect of improvement.",
        "positive": "Calculation Of Hadronic Matrix Elements Relevant For Delta I=1/2 Rule\n  And Epsilon-prime In Lattice QCD With Staggered Fermions: This thesis presents the setup and results of numerical calculation of\nhadronic matrix elements of Delta S=1 weak operators, with the aim of studying\nthe Delta I=1/2 rule and direct CP violation. Such study provides a useful\ncomparison of the Standard Model predictions with experiment. We work within\nthe framework of (partially quenched) Lattice QCD with the staggered\n(Kogut-Susskind) version of fermions. We have achieved a reasonable statistical\naccuracy in calculating all matrix elements in question. Based on these\nresults, we find that the Delta I=1/2 channel in K to 2 Pi decays is enhanced\ncompared to the Delta I=3/2 channel. This is consistent with experiment,\nalthough the exact amount of enhancement is subject to considerable systematic\nerrors. I also discuss the difficulties encountered in attempting to calculate\nthe direct CP violation parameter epsilon-prime and our approximate solution\nleading to a crude estimate. In a related study we nonperturbatively compute\nbilinear renormalization factors Z_S and Z_P, which are needed for our estimate\nof epsilon-prime and also allow to calculate the light quark masses. For the\nstrange quark mass in NDR MS-bar scheme at 2 GeV in the quenched approximation\nwe find: m_s = 102.9 +/- 5.1 MeV."
    },
    {
        "anchor": "The phase diagram of QCD with four degenerate quarks: We revisit the determination of the pseudo-critical line of QCD with four\ndegenerate quarks at non-zero temperature and baryon density by the method of\nanalytic continuation. We determine the pseudo-critical couplings at imaginary\nchemical potentials by high-statistics Monte Carlo simulations and reveal\ndeviations from the simple quadratic dependence on the chemical potential\nvisible in earlier works on the same subject. Finally, we discuss the\nimplications of our findings for the shape of the pseudo-critical line at real\nchemical potential, comparing different possible extrapolations.",
        "positive": "From Domain Wall to Overlap in 2+1d: The equivalence of domain wall and overlap fermion formulations is\ndemonstrated for lattice gauge theories in 2+1 spacetime dimensions with\nparity-invariant mass terms. Even though the domain wall approach distinguishes\npropagation along a third direction with projectors ${1\\over2}(1\\pm\\gamma_3)$,\nthe truncated overlap operator obtained for finite wall separation $L_s$ is\ninvariant under interchange of $\\gamma_3$ and $\\gamma_5$. In the limit\n$L_s\\to\\infty$ the resulting Ginsparg-Wilson relations recover the expected\nU($2N_f$) global symmetry up to O($a$) corrections. Finally it is shown that\nfinite-$L_s$ corrections to bilinear condensates associated with dynamical mass\ngeneration are characterised by whether even powers of the symmetry-breaking\nmass are present; such terms are absent for antihermitian bilinears such as\n$i\\bar\\psi\\gamma_3\\psi$, markedly improving the approach to the large-$L_s$\nlimit."
    },
    {
        "anchor": "Lattice study of large $N_c$ QCD: We present a lattice simulation study of large $N_c$ regularities of meson\nand baryon spectroscopy in $SU(N_c)$ gauge theory with two flavors of dynamical\nfundamental representation fermions. Systems investigated include $N_c=2$, 3,\n4, and 5, over a range of fermion masses parametrized by a squared pseudoscalar\nto vector meson mass ratio between about 0.2 to 0.7. Good agreement with large\n$N_c$ scaling is observed in the static potential, in meson masses and decay\nconstants, and in baryon spectroscopy. This is an update of the published\nversion of the paper (Phys. Rev. D94 (2016) 034506).",
        "positive": "Light scalar spectrum in extra-dimensional gauge theories: The phase diagram of five-dimensional SU(2) gauge theories with one\ncompactified dimension on anisotropic lattices has a rich structure. In this\ncontribution we show how to control non-perturbatively the scale hierarchy\nbetween the cut-off and the compactification scale in the bare parameter space.\nThere exists a set of strong bare couplings where the the five-dimensional\nlattice theory can be described by an effective four-dimensional theory with a\nscalar field in the adjoint representation. We present a detailed study of the\nlight scalar spectrum as it arises from the non-perturbative dynamics of the\nfull five-dimensional lattice theory. We also investigate the mixing with\nscalar glueball states in the attempt to further establish the\nextra-dimensional nature of light scalar states."
    },
    {
        "anchor": "Stochastic automatic differentiation for Monte Carlo processes: Monte Carlo methods represent a cornerstone of computer science. They allow\nto sample high dimensional distribution functions in an efficient way. In this\npaper we consider the extension of Automatic Differentiation (AD) techniques to\nMonte Carlo process, addressing the problem of obtaining derivatives (and in\ngeneral, the Taylor series) of expectation values. Borrowing ideas from the\nlattice field theory community, we examine two approaches. One is based on\nreweighting while the other represents an extension of the Hamiltonian approach\ntypically used by the Hybrid Monte Carlo (HMC) and similar algorithms. We show\nthat the Hamiltonian approach can be understood as a change of variables of the\nreweighting approach, resulting in much reduced variances of the coefficients\nof the Taylor series. This work opens the door to find other variance reduction\ntechniques for derivatives of expectation values.",
        "positive": "Matrix Elements of 4-fermion Operators with Quenched Wilson Fermions: We presents results for the matrix elements of a variety of four-fermion\noperators calculated using quenched Wilson fermions. Our simulations are done\non 170 lattices of size $32^3 x 64$ at $\\beta = 6.0$. We find $B_K=0.74 +- 0.04\n+- 0.05$, $B_D= 0.78 +- 0.01$, $B_7^{3/2}= 0.58 +- 0.02 {+0.07 \\atop -0.03}$,\n$B_8^{3/2}= 0.81 +- 0.03 {+.03 \\atop -0.02}$, with all results being in the NDR\nscheme at $\\mu=2 GeV$. We also calculate the B-parameter for the operator\n$\\CQ_s$, which is needed in the study of the difference of B-meson lifetimes.\nOur best estimate is $B_s(NDR,\\mu=1/a)=0.80 +- 0.01$. This is given at the\nlattice scale since the required 2-loop anomalous dimension matrix is not\nknown. In all these estimates, the first error is statistical, while the second\nis due to the use of truncated perturbation theory to match continuum and\nlattice operators. Errors due to quenching and lattice discretization are not\nincluded. We also present new results for the perturbative matching\ncoefficients, extending the calculation to all Lorentz scalar four-fermion\noperators, and using NDR as the continuum scheme."
    },
    {
        "anchor": "Hierarchical probing for estimating the trace of the matrix inverse on\n  toroidal lattices: The standard approach for computing the trace of the inverse of a very large,\nsparse matrix $A$ is to view the trace as the mean value of matrix quadratures,\nand use the Monte Carlo algorithm to estimate it. This approach is heavily used\nin our motivating application of Lattice QCD. Often, the elements of $A^{-1}$\ndisplay certain decay properties away from the non zero structure of $A$, but\nrandom vectors cannot exploit this induced structure of $A^{-1}$. Probing is a\ntechnique that, given a sparsity pattern of $A$, discovers elements of $A$\nthrough matrix-vector multiplications with specially designed vectors. In the\ncase of $A^{-1}$, the pattern is obtained by distance-$k$ coloring of the graph\nof $A$. For sufficiently large $k$, the method produces accurate trace\nestimates but the cost of producing the colorings becomes prohibitively\nexpensive. More importantly, it is difficult to search for an optimal $k$\nvalue, since none of the work for prior choices of $k$ can be reused.",
        "positive": "Improved convergence of Complex Langevin simulations: The sign problem appears in lattice QCD as soon as a non-zero chemical\npotential is introduced. This prevents direct simulations to determine the\nphase structure of the strongly interacting matter. Complex Langevin methods\nhave been successfully used for various models or approximations of QCD.\nHowever, in some scenarios it converges to incorrect results. We present\ndevelopments of our new method that helps to improve the convergence by keeping\nthe system closer to the SU(3) manifold and discuss preliminary tests and\nresults."
    },
    {
        "anchor": "Nucleons and parity doubling across the deconfinement transition: It is expected that nucleons and their parity partners become degenerate when\nchiral symmetry is restored. We investigate this question in the context of the\nthermal transition from the hadronic phase to the quark-gluon plasma, using\nlattice QCD simulations with N_f=2+1 flavours. We observe a clear sign of\nparity doubling in the quark-gluon plasma. Besides, we find that the nucleon\nground state is, within the uncertainty, largely independent of the\ntemperature, whereas temperature effects are substantial in the negative-parity\n(N^*) channel, already in the confined phase.",
        "positive": "Entanglement entropy in SU(N) gauge theory: The entanglement entropy of SU(N) lattice gauge theory is studied exactly in\n1+1 space-time dimensions and in Migdal-Kadanoff approximation in higher\ndimensional space. The existence of a non-analytical behavior reminiscent of a\nphase transition for a characteristic size of the entangled region is\ndemonstrated for higher dimensional theories."
    },
    {
        "anchor": "Disconnected contributions to hadronic structure: We present an update of an on-going project to determine the disconnected\ncontributions to hadronic structure, specifically, the scalar matrix element\nand the quark contribution to the spin of the nucleon.",
        "positive": "Infinitely many regulator fields for chiral fermions: We show that two recent independent proposals for regularizing a chiral gauge\ntheory stem from one common trick. If the anomaly free complex representation\ncarried by the right handed fermi--fields is $r$ one constructs a vector like\ntheory with flavored right handed fermionic matter in $r+\\bar r$ but with a\nmass matrix of the order of the cutoff and having an index equal to unity in an\ninfinite dimensional flavor space. We present a Pauli--Villars realization of\nthe trick that is likely to work to all orders in perturbation theory and a\nlattice version which is argued to produce the correct continuum leading order\nfermionic contribution to the vacuum polarization tensor and readied for\nfurther perturbative checks."
    },
    {
        "anchor": "Gluon Quasi-PDF From Lattice QCD: We present the first attempt to access the $x$-dependence of the gluon\nunpolarized parton distribution function (PDF), based on lattice simulations\nusing the large-momentum effective theory (LaMET) approach. The lattice\ncalculation is carried out with pion masses of 340 and 678 MeV on a 2+1-flavor\nDWF configuration with lattice spacing $a=0.111$~fm, for the gluon quasi-PDF\nmatrix element with the nucleon momentum up to 0.93 GeV. Taking the\nnormalization from similar matrix elements in the rest frame of the nucleon and\npion, our results for these matrix elements are consistent with the Fourier\ntransform of the global fit CT14 and PDF4LHC15 NNLO of the gluon PDF, within\nstatistical uncertainty and the systematic one up to power corrections,\nperturbative ${\\cal O}(\\alpha_s)$ matching and the mixing from the quark PDFs.",
        "positive": "Quark number susceptibility at high temperature: We use three dimensional reduced effective field theory (EQCD) and lattice\ncalculations to determine the quark number susceptibility of QCD at high\ntemperature. We find our results to agree well with known perturbative\nexpansion as well as with other lattice data."
    },
    {
        "anchor": "Positivity of center subsets for QCD: We further pursue an approach to the sign problem of quantum chromodynamics\nat nonzero chemical potential, in which configurations of the lattice path\nintegral are gathered into subsets. In the subset construction we multiply each\ntemporal link by center elements independently and in a first step neglect the\ngauge action. The positivity of the subset weights -- shown for 0+1 dimensions\nin an earlier study -- extends to larger lattices: for two sites in the\ntemporal direction and arbitrary spatial extent we give a proof of the\npositivity by decomposing the subset weight in positive summands. From\nnumerical evidence we conjecture that the positivity persists on larger\nlattices and that the gauge action can be reintroduced through mild\nreweighting. First results on the quark number obtained with this method in two\ndimensions are shown as well.",
        "positive": "Glueball Mass Predictions of the Valence Approximation to Lattice QCD: We evaluate the infinite volume, continuum limit of glueball masses in the\nvalence (quenched) approximation to lattice QCD. For the lightest states with\n$J^{PC}$ of $0^{++}$ and $2^{++}$, we obtain $m_0 = 1340 \\pm 160$ MeV and $m_2\n= 1900 \\pm 320$ MeV."
    },
    {
        "anchor": "Magnetic polarizabilities of light mesons in $SU(3)$ lattice gauge\n  theory: We investigate the masses (ground state energies) of neutral pseudoscalar and\nvector meson in $SU(3)$ lattice gauge theory in strong abelian magnetic field.\nThe energy of $\\rho^0$ meson with zero spin projection $s_z=0$ on the axis of\nthe external magnetic field decreases, while the energies with non-zero spins\n$s_z=-1$ and $+1$ increase with the field. The energy of $\\pi^0$ meson decrease\nas a function of the magnetic field. We calculated the magnetic\npolarizabilities of pseudoscalar and vector mesons for lattice volume $18^4$.\nFor $\\rho^0$ with spin $|s_z|=1$ and $\\pi^0$ meson the extrapolations to zero\nlattice spacing have been done. We do not observe any evidence in favour of\ntachyonic mode existence.",
        "positive": "$\u039b_c\u03a3_c\u03c0$ coupling and $\u03a3_c \\rightarrow\u039b_c \u03c0$\n  decay in lattice QCD: We evaluate the $\\Lambda_c\\Sigma_c\\pi$ coupling constant ($G_{\\Lambda_c\n\\Sigma_c \\pi}$) and the width of the strong decay $\\Sigma_c\n\\rightarrow\\Lambda_c \\pi$ in 2+1 flavor lattice QCD on four different ensembles\nwith pion masses ranging from 700 MeV to 300 MeV. We find $G_{\\Lambda_c\n\\Sigma_c \\pi}=18.332(1.476)_{\\rm{stat.}}(2.171)_{\\rm{syst.}}$ and the decay\nwidth $\\Gamma(\\Sigma_c \\rightarrow\\Lambda_c\n\\pi)=1.65(28)_{\\rm{stat.}}(30)_{\\rm{syst.}}$~MeV on the physical quark-mass\npoint, which is in agreement with the recent experimental determination."
    },
    {
        "anchor": "Phase diagram of QCD in strong background magnetic field: We discuss the phase diagram of QCD in the presence of a strong background\nmagnetic field, providing numerical evidence, based on lattice simulations of\nQCD with $2+1$ flavours and physical quark masses, that the QCD crossover turns\ninto a first order phase transition for large enough magnetic field, with a\ncritical endpoint located between $eB=4$ GeV$^2$ (where we found an analytic\ncrossover at a pseudo-critical temperature $T_c=(98\\pm3)$ MeV) and $eB=9$\nGeV$^2$ (where the measured critical temperature is $T_c=(63\\pm5)$ MeV).",
        "positive": "Unifying all classical spin models in a Lattice Gauge Theory: We show that the partition function of all classical spin models, including\nall discrete Standard Statistical Models and all abelian discrete Lattice Gauge\nTheories (LGTs), can be expressed as a special instance of the partition\nfunction of the 4D Z_2 LGT. In this way, all classical spin models with\napparently very different features are unified in a single complete model, and\na physical relation between all models is established. As applications of this\nresult, we present a new method to do mean field theory for abelian discrete\nLGTs with d>3, and we show that the computation of the partition function of\nthe 4D Z_2 LGT is a computationally hard (#P-hard) problem. We also extend our\nresults to abelian continuous models, where we show the approximate\ncompleteness of the 4D Z_2 LGT. All results are proven using quantum\ninformation techniques."
    },
    {
        "anchor": "The eta and eta' mesons from lattice QCD: Lattice QCD allows a first-principles study of QCD with the freedom to vary\nthe number and masses of the quarks. I present results on the flavour singlet\ncorrelations (this illuminates OZI violating effects) for mesons. Concentrating\non the pseudoscalar mesons, the flavour singlet mass splitting ($\\eta$, $\\eta'$\nmass splitting) appears naturally.\n  I also present results on an investigation of decay constants for the $\\eta$\nand $\\eta'$ ($f_{\\eta}$) and discuss which quantities may be accessible in\nfuture lattice studies.\n  The Witten-Veneziano approach can also be explored by determining the\nquenched topological susceptibility on a lattice.",
        "positive": "Lattice fermions with gauge noninvariant measure: We define Weyl fermions on a finite lattice in such a way that in the path\nintegral the action is gauge invariant but the functional measure is not. Two\nvariants of such a formulation are tested in perturbative calculation of the\nfermion determinant in chiral Schwinger model. We find that one of these\nvariants ensures restoring the gauge invariance of the nonanomalous part of the\ndeterminant in the continuum limit. A `perfect' perturbative regularization of\nthe chiral fermions is briefly discussed."
    },
    {
        "anchor": "The pion vector form factor from Lattice QCD at the physical point: We present an investigation of the electromagnetic pion form factor,\n$F_\\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\\lesssim\n0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted\nMass Collaboration with $N_f = 2$ twisted-mass quarks at maximal twist\nincluding a clover term. Momentum is injected using non-periodic boundary\nconditions and the calculations are carried out at a fixed lattice spacing ($a\n\\simeq 0.09$ fm) and with pion masses equal to its physical value, 240 MeV and\n340 MeV. Our data are successfully analyzed using Chiral Perturbation Theory at\nnext-to-leading order in the light-quark mass. For each pion mass two different\nlattice volumes are used to take care of finite size effects. Our final result\nfor the squared charge radius is $\\langle r^2 \\rangle_\\pi = 0.443~(29)$ fm$^2$,\nwhere the error includes several sources of systematic errors except the\nuncertainty related to discretization effects. The corresponding value of the\nSU(2) chiral low-energy constant $\\overline{\\ell}_6$ is equal to\n$\\overline{\\ell}_6 = 16.2 ~ (1.0)$.",
        "positive": "Chromoelectric flux tubes in QCD: We analyze the distribution of the chromoelectric field generated by a static\nquark-antiquark pair in the SU(3) vacuum and revisit previous results for\nSU(2). We find that the transverse profile of the flux tube resembles the dual\nversion of the Abrikosov vortex field distribution. We give an estimate of the\nLondon penetration length of the chromoelectric field in the confined vacuum.\nWe also speculate on the value of the ratio between the penetration lengths for\nSU(2) and SU(3) gauge theories."
    },
    {
        "anchor": "Perturbative renormalization functions of local operators for staggered\n  fermions with stout improvement: In this paper we present the perturbative computation of the renormalization\nfunctions for the quark field and for a complete set of ultra-local fermion\nbilinears. The computation of the relevant Green's functions was carried out at\n1-loop level for the staggered action using massive fermions. The gluon links\nwhich appear both in the fermion action and in the definition of the bilinears\nhave been improved by applying a stout smearing procedure up to 2 times,\niteratively. In the gluon sector we employed the Symanzik improved gauge action\nfor different sets of values of the Symanzik coefficients. The renormalization\nfunctions are presented in (two variants of) the RI' and in the MSbar\nrenormalization scheme; the dependence on all stout parameters, as well as on\nthe fermion mass, the gauge fixing parameter and the renormalization scale, is\nshown explicitly. This work is related to our recent paper [Phys. Rev. D86\n(2012) 094512, arXiv:1209.6015]. To make our results easily accessible to the\nreader, we include them in the distribution package of this paper, as a\nMathematica input file, Staggered.m.",
        "positive": "Heavy-quark meson spectrum tests of the Oktay-Kronfeld action: The Oktay-Kronfeld (OK) action extends the Fermilab improvement program for\nmassive Wilson fermions to higher order in suitable power-counting schemes. It\nincludes dimension-six and -seven operators necessary for matching to QCD\nthrough order ${\\mathrm{O}}(\\Lambda^3/m_Q^3)$ in HQET power counting, for\napplications to heavy-light systems, and ${\\mathrm{O}}(v^6)$ in NRQCD power\ncounting, for applications to quarkonia. In the Symanzik power counting of\nlattice gauge theory near the continuum limit, the OK action includes all\n${\\mathrm{O}}(a^2)$ and some ${\\mathrm{O}}(a^3)$ terms. To assess whether the\ntheoretical improvement is realized in practice, we study combinations of\nheavy-strange and quarkonia masses and mass splittings, designed to isolate\nheavy-quark discretization effects. We find that, with one exception, the\nresults obtained with the tree-level-matched OK action are significantly closer\nto the continuum limit than the results obtained with the Fermilab action. The\nexception is the hyperfine splitting of the bottom-strange system, for which\nour statistical errors are too large to draw a firm conclusion. These studies\nare carried out with data generated with the tadpole-improved Fermilab and OK\nactions on 500 gauge configurations from one of MILC's $a\\approx0.12$~fm,\n$N_f=2+1$-flavor, asqtad-staggered ensembles."
    },
    {
        "anchor": "Unquenching the Schwinger Model (revised): We study the quenched and unquenched lattice Schwinger model with Wilson\nfermions. The lowest non-trivial order of the systematic expansion recently\nproposed by Sexton and Weingarten is shown to allow good estimates of long\ndistance physics from quenched configurations. Results for the static potential\nand the lowest bound state mass are presented.",
        "positive": "Monopole Condensation in full QCD using the Schroedinger Functional: We use a lattice thermal partition functional to study Abelian monopole\ncondensation in full QCD with $N_f=2$ staggered fermions. We present\npreliminary results on $16^3\\times4$ and $32^3\\times4$ lattices."
    },
    {
        "anchor": "I=1/2 low-lying mesons in lattice QCD: Using conventional constituent-quark model, $I=1/2$ scalar $\\kappa$, vector\n$K^\\ast(892)$, and axial vector $K_1$ mesons are studied in the asqtad-improved\nstaggered fermion with the wall-source and point-sink interpolators. The mass\nratio of $m_{\\kappa}/m_{K^\\ast(892)}$ is numerically confirmed to vary\napparently with quark mass, and the experimental ordering $m_{K^\\ast(892)} >\nm_{\\kappa}$ is elegantly hold when the light $u/d$ quark masses are\nsufficiently small, while the valence strange quarks are fixed to its physical\nvalues. We also get reasonable signals for $K_1$ meson suggested by SCALAR\nCollaboration from lattice QCD. The computations are conducted with the MILC\n$N_f=3$ flavor gauge configurations at three lattice spacings: $a\\approx 0.15$,\n$0.12$, and $0.09$ fm.",
        "positive": "The theoretical background and properties of perfect actions: This lecture note starts with a pedagogical introduction to the theoretical\nbackground and properties of perfect actions, gives some details on topology\nand instanton solutions and ends with a discussion on the recent developments\nconcerning chiral symmetry."
    },
    {
        "anchor": "Momentum broadening of partons on the light cone from the lattice: The jet quenching parameter describes the momentum broadening of a\nhigh-energy parton moving through the quark-gluon plasma. Following an approach\noriginally proposed by Caron-Huot, we discuss how one can extract information\non the collision kernel associated with the parton momentum broadening, from\nthe analysis of certain gauge-invariant operators in dimensionally reduced\neffective theories, and present numerical results from a lattice study.",
        "positive": "Quantum error thresholds for gauge-redundant digitizations of lattice\n  field theories: In the quantum simulation of lattice gauge theories, gauge symmetry can be\neither fixed or encoded as a redundancy of the Hilbert space. While\ngauge-fixing reduces the number of qubits, keeping the gauge redundancy can\nprovide code space to mitigate and correct quantum errors by checking and\nrestoring Gauss's law. In this work, we consider the correctable errors for\ngeneric finite gauge groups and design the quantum circuits to detect and\ncorrect them. We calculate the error thresholds below which the gauge-redundant\ndigitization with Gauss's law error correction has better fidelity than the\ngauge-fixed digitization. Our results provide guidance for fault-tolerant\nquantum simulations of lattice gauge theories."
    },
    {
        "anchor": "The static quark self-energy at large orders from NSPT: Using Numerical Stochastic Perturbation Theory (NSPT), we calculate the\nstatic self-energy of SU(3) gauge theory up to order \\alpha^{20}. Simulations\non a large set of different lattice volumes allow for a careful treatment of\nfinite size effects. The resulting infinite volume perturbative series of the\nstatic self-energy is in remarkable agreement with the predicted asymptotic\nbehaviour of high order expansions, namely with a factorial growth of\nperturbative coefficients known as renormalon.",
        "positive": "Interaction studies of a heavy-light meson-baryon system: We study time correlation functions of operators representing heavy-light\nK-Lambda like systems at various relative distances r. The heavy quarks, one in\neach hadron, are treated as static. An anisotropic and asymmetric lattice is\nused with Wilson fermions. Our goal is to extract an adiabatic potential and\nthus learn about the physics of the five-quark system viewed as an hadronic\nmolecule."
    },
    {
        "anchor": "The $B\\to K^*$ form factors on the lattice: The extraction of the $B\\to K^*$ transition form factors from lattice data is\nstudied, applying non-relativistic effective field theory in a finite volume.\nThe possible mixing of $\\pi K$ and $\\eta K$ states is taken into account. The\ntwo-channel analogue of the Lellouch-L\\\"uscher formula is reproduced. Due to\nthe resonance nature of the $K^*$, an equation is derived, which allows to\ndetermine the form factors at the pole position in a process-independent\nmanner. The infinitely-narrow width approximation of the results is discussed.",
        "positive": "Nucleon Electric Dipole Moment from the $\u03b8$ Term with Lattice\n  Chiral Fermions: We calculate the nucleon electric dipole moment (EDM) from the $\\theta$ term\nwith overlap fermions on three domain wall lattices with different sea pion\nmasses at lattice spacing 0.11 fm. Due to the chiral symmetry conserved by the\noverlap fermions, we have well defined topological charge and chiral limit for\nthe EDM. Thus, the chiral extrapolation can be carried out reliably at nonzero\nlattice spacings. We use three to four different partially quenched valence\npion masses for each sea pion mass and find that the EDM dependence on the\nvalence and sea pion masses behaves oppositely, which can be described by\npartially quenched chiral perturbation theory. With the help of the cluster\ndecomposition error reduction (CDER) technique, we determine the neutron and\nproton EDM at the physical pion mass to be\n$d_{n}=-0.00148\\left(14\\right)\\left(31\\right)\\bar\\theta$ e$\\cdot$fm and\n$d_{p}=0.0038\\left(11\\right)\\left(8\\right)\\bar\\theta$ e$\\cdot$fm. This work is\na clear demonstration of the advantages of using chiral fermions in the nucleon\nEDM calculation and paves the road to future precise studies of the strong $CP$\nviolation effects."
    },
    {
        "anchor": "Improving the lattice axial vector current: For Wilson and clover fermions traditional formulations of the axial vector\ncurrent do not respect the continuum Ward identity which relates the divergence\nof that current to the pseudoscalar density. Here we propose to use a\npoint-split or one-link axial vector current whose divergence exactly satisfies\na lattice Ward identity, involving the pseudoscalar density and a number of\nirrelevant operators. We check in one-loop lattice perturbation theory with\nSLiNC fermion and gauge plaquette action that this is indeed the case including\norder $O(a)$ effects. Including these operators the axial Ward identity remains\nrenormalisation invariant. First preliminary results of a nonperturbative check\nof the Ward identity are also presented.",
        "positive": "The Charmonium Spectrum on the Lattice: A Status Report: We present our most recent results on the charmonium spectrum using\nrelativistic Wilson fermions. We study the dependence of the spectrum on the\ncharm quark mass and the Wohlert-Sheikholeslami improvement term."
    },
    {
        "anchor": "Excited $J^{--}$ meson resonances at the SU(3) flavor point from lattice\n  QCD: We present the first calculation within lattice QCD of excited light meson\nresonances with $J^{PC} = 1^{--}$, $2^{--}$ and $3^{--}$. Working with an exact\nSU(3) flavor symmetry, for the singlet representation of pseudoscalar-vector\nscattering, we find two $1^{--}$ resonances, a lighter broad state and a\nheavier narrow state, a broad $2^{--}$ resonance decaying in both $P$- and\n$F$-waves, and a narrow $3^{--}$ state. We present connections to experimental\n$\\omega^\\star_J, \\phi^\\star_J$ resonances decaying into $\\pi \\rho$,\n$K\\bar{K}^*$, $\\eta \\omega$ and other final states.",
        "positive": "$B\\to\u03c0\\ell\u03bd$ and $B\\to\u03c0\\ell^+\\ell^-$ semileptonic form factors\n  from unquenched lattice QCD: We update the lattice calculation of the $B\\to\\pi$ semileptonic form factors,\nwhich have important applications to the CKM matrix element $|V_{ub}|$ and the\n$B\\to\\pi\\ell^+\\ell^-$ rare decay. We use MILC asqtad ensembles with $N_f=2+1$\nsea quarks and over a range of lattice spacings $a \\approx 0.045$--$0.12$ fm.\nWe perform a combined chiral and continuum extrapolation of our lattice data\nusing SU(2) staggered chiral perturbation theory in the hard pion limit. To\nextend the results for the form factors to the full kinematic range, we take a\nfunctional approach to parameterize the form factors using the\nBourrely-Caprini-Lellouch formalism in a model-independent way. Our analysis is\nstill blinded with an unknown off-set factor which will be disclosed when we\npresent the final results."
    },
    {
        "anchor": "Monte Carlo studies of dynamical compactification of extra dimensions in\n  a model of nonperturbative string theory: The IIB matrix model has been proposed as a non-perturbative definition of\nsuperstring theory. In this work, we study the Euclidean version of this model\nin which extra dimensions can be dynamically compactified if a scenario of\nspontaneously breaking the SO(10) rotational symmetry is realized. Monte Carlo\ncalculations of the Euclidean IIB matrix model suffer from a very strong\ncomplex action problem due to the large fluctuations of the complex phase of\nthe Pfaffian which appears after integrating out the fermions. We employ the\nfactorization method in order to achieve effective sampling. We report on\npreliminary results that can be compared with previous studies of the\nrotational symmetry breakdown using the Gaussian expansion method.",
        "positive": "Complex Langevin in Lattice QCD: dynamic stabilisation and the phase\n  diagram: Complex Langevin simulations provide an alternative to sample path integrals\nwith complex weights and therefore are suited to determine the phase diagram of\nQCD from first principles. We use our proposed method of Dynamic Stabilisation\n(DS) to ensure improved convergence to the right limit and present new\nsystematic tests of this technique. We also show results on QCD in the limit of\nheavy quarks and an analysis of DS compared to known results from reweighting."
    },
    {
        "anchor": "Calculation of the hadronic vacuum polarization disconnected\n  contribution to the muon anomalous magnetic moment: We report the first lattice QCD calculation of the hadronic vacuum\npolarization disconnected contribution to the muon anomalous magnetic moment at\nphysical pion mass. The calculation uses a refined noise-reduction technique\nwhich enabled the control of statistical uncertainties at the desired level\nwith modest computational effort. Measurements were performed on the $48^3\n\\times 96$ physical-pion-mass lattice generated by the RBC and UKQCD\ncollaborations. We find $a_\\mu^{\\rm HVP~(LO)~DISC} = -9.6(3.3)(2.3)\\times\n10^{-10}$, where the first error is statistical and the second systematic.",
        "positive": "Fake symmetry transitions in lattice Dirac spectra: In a recent lattice investigation of Ginsparg-Wilson-type Dirac operators in\nthe Schwinger model, it was found that the symmetry class of the random matrix\ntheory describing the small Dirac eigenvalues appeared to change from the\nunitary to the symplectic case as a function of lattice size and coupling\nconstant. We present a natural explanation for this observation in the\nframework of a random matrix model, showing that the apparent change is caused\nby the onset of chiral symmetry restoration in a finite volume. A transition\nfrom unitary to symplectic symmetry does not occur."
    },
    {
        "anchor": "Diquark condensation in two colour QCD: Unquenched lattice SU(2) is studied at nonzero chemical potential in the\nstrong coupling limit. The topic of diquark condensation is addressed analyzing\nthe probability distribution function of the diquark condensate. We present\nresults at zero external source without using any potentially dangerous\nextrapolation procedure. We find strong evidences for a (high density) second\norder phase transition where a diquark condensate appears, and show\nquantitative agreement of lattice calculations with low-energy effective\nLagrangian calculations.",
        "positive": "Nucleon Magnetic Properties from Lattice QCD with the Background Field\n  Method: The magnetic moment and magnetic polarisability of the neutron and proton are\ninvestigated using the uniform background-field method and lattice QCD. The\nresults are calculated using 32^3 x 64 dynamical QCD lattices provided by the\nPACS-CS collaboration through the ILDG. Methods of isolating the energy of the\nhadrons accounting for Landau level energies are explored. Effective energy\nshifts are formed from combinations of correlation functions and their\nefficiency in isolating the magnetic moment and polarisability terms is\ndetermined."
    },
    {
        "anchor": "Light quark masses from quenched lattice QCD simulations with domain\n  wall quarks: Values for the strange quark mass and average up/down mass have been obtained\nfrom quenched lattice QCD simulations using the domain wall fermion action.\nThis discretization preserves the properties of flavor and chiral symmetry at\nnonzero lattice spacing. Results are shown for two values of the lattice\nspacing. The mass renormalization constant is computed nonperturbatively.",
        "positive": "Supersymmetry, chiral symmetry and the generalized BRS transformation in\n  lattice formulations of 4D $\\mathcal{N}=1$ SYM: In the context of the lattice regularization of the four-dimensional\n$\\mathcal{N}=1$ supersymmetric Yang--Mills theory (4D $\\mathcal{N}=1$ SYM), we\nformulate a generalized BRS transformation that treats the gauge, supersymmetry\n(SUSY), translation and axial U(1) ($U(1)_A$) transformations in a unified way.\nA resultant Slavnov--Taylor identity or the Zinn-Justin equation gives rise to\na strong constraint on the quantum continuum limit of symmetry breaking terms\nwith the lattice regularization. By analyzing the implications of the\nconstraint on operator-mixing coefficients in the SUSY and the $U(1)_A$\nWard-Takahashi (WT) identities, we prove to all orders of perturbation theory\nin the continuum limit that, (i) the chiral symmetric limit implies the\nsupersymmetric limit and, (ii) a three-fermion operator that might potentially\ngive rise to an exotic breaking of the SUSY WT identity does not emerge. In\nprevious literature, only a naive or incomplete treatment on these points can\nbe found. Our results provide a solid theoretical basis for lattice\nformulations of the 4D $\\mathcal{N}=1$ SYM."
    },
    {
        "anchor": "Using Gradient Flow to Renormalise Matrix Elements for Meson Mixing and\n  Lifetimes: Neutral meson mixing and meson lifetimes are theory-side parametrised in\nterms four-quark operators which can be determined by calculating weak decay\nmatrix elements using lattice Quantum Chromodynamics. While calculations of\nmeson mixing matrix elements are standard, determinations of lifetimes\ntypically suffer from complications in renormalisation procedures because\ndimension-6 four-quark operators can mix with operators of lower mass dimension\nand, moreover, quark-line disconnected diagrams contribute.\n  We present work detailing the idea to use fermionic gradient flow to\nnon-perturbatively renormalise matrix elements describing meson mixing or\nlifetimes, and combining it with a perturbative calculation to match to the\n$\\overline{\\rm MS}$ scheme using the shoft-flow-time expansion.",
        "positive": "The Mass of the b Quark from Lattice NRQCD: We present results for the mass of the $b$ quark in the $\\bar{MS}$ scheme\nobtained by calculating the binding energy of the $B$ meson in the static\nlimit. The self energy of a static quark, $E_0^\\infty$ needed for this purpose,\nis now known to $O(\\alpha^3)$ in the quenched approximation. We find a {\\it\npreliminary} value of $\\bar{m_b}(\\bar{m_b})=4.34(7)$ GeV at $n_f=0$. The error\nis dominated by the remaining uncertainty in $E_0^\\infty$. In addition, using\n$E_0^\\infty$ at $O(\\alpha^2)$, we estimate that the quark mass is reduced by\napproximately 70 MeV when two flavours of dynamical quarks are introduced."
    },
    {
        "anchor": "The pion's electromagnetic form factor at small momentum transfer in\n  full lattice QCD: We compute the electromagnetic form factor of a \"pion\" with mass m_pi=330MeV\nat low values of Q^2\\equiv -q^2, where q is the momentum transfer. The\ncomputations are performed in a lattice simulation using an ensemble of the\nRBC/UKQCD collaboration's gauge configurations with Domain Wall Fermions and\nthe Iwasaki gauge action with an inverse lattice spacing of 1.73(3)GeV. In\norder to be able to reach low momentum transfers we use partially twisted\nboundary conditions using the techniques we have developed and tested earlier.\nFor the pion of mass 330MeV we find a charge radius given by\n<r_pi^2>_{330MeV}=0.354(31)fm^2 which, using NLO SU(2) chiral perturbation\ntheory, extrapolates to a value of <r_pi^2>=0.418(31)fm^2 for a physical pion,\nin agreement with the experimentally determined result. We confirm that there\nis a significant reduction in computational cost when using propagators\ncomputed from a single time-slice stochastic source compared to using those\nwith a point source; for m_pi=330MeV and volume (2.74fm)^3 we find the\nreduction is approximately a factor of 12.",
        "positive": "Clover improvement for stout-smeared 2+1 flavour SLiNC fermions:\n  perturbative results: For the Stout Link Non-perturbative Clover (SLiNC) action we determine in\none-loop lattice perturbation theory the critical hopping parameter $\\kappa_c$\nand the clover parameter $c_{SW}$ which is needed for $\\mathcal{O}(a)$\nimprovement. Performing this calculation off-shell we are also able to compute\nthe non gauge invariant quark field improvement coefficient $c_{NGI}$.\nAdditionally, we present first results for the renormalization factors of the\nscalar, pseudoscalar, vector and axial vector currents. We discuss mean field\nimprovement for the SLiNC action."
    },
    {
        "anchor": "Exact Lattice Supersymmetry at the Quantum Level for N=2 Wess-Zumino\n  models in Lower Dimensions: We have recently proposed a new lattice SUSY formulation which has exact\nlattice supersymmetry for Wess-Zumino models in one and two dimensions for all\nN=2 supercharges. This formulation is non-local in the coordinate space but the\ndifference operator satisfies the Leibniz rule on the newly defined star\nproduct. Here we show that this lattice supersymmetry is kept exact at the\nquantum level by investigating Ward-Takahashi identities up to two loop level.",
        "positive": "Infrared features of unquenched finite temperature lattice Landau gauge\n  QCD: The color diagonal and color antisymmetric ghost propagators slightly above\n$T_c$ of $N_f=2$ MILC $24^3\\times 12$ lattices are measured and compared with\nzero temperature unquenched $N_f=2+1$ MILC$_c$ $20^3\\times 64$ and MILC$_f$\n$28^3\\times 96$ lattices and zero temperature quenched $56^4$ $\\beta=6.4$ and\n6.45 lattices. The expectation value of the color antisymmetric ghost\npropagator $\\phi^c(q)$ is zero but its Binder cumulant, which is consistent\nwith that of $N_c^2-1$ dimensional Gaussian distribution below $T_c$, decreases\nabove $T_c$. Although the color diagonal ghost propagator is temperature\nindependent, the $l^1$ norm of the color antisymmetric ghost propagator is\ntemperature dependent. The expectation value of the ghost condensate observed\nat zero temperature unquenched configuration is consistent with 0 in $T>T_c$.\n  We also measure transverse, magnetic and electric gluon propagator and\nextract gluon screening masses. The running coupling measured from the product\nof the gluon dressing function and the ghost dressing function are almost\ntemperature independent but the effect of $A^2$ condensate observed at zero\ntemperature is consistent with 0 in $T>T_c$.\n  The transverse gluon dressing function at low temperature has a peak in the\ninfrared but it becomes flatter at high temperature. Its absolute value in the\nhigh momentum is larger for high temperature and similar to the magnetic gluon\ndressing function. The electric gluon propagator at high momentum is\ntemperature independent. These data imply that the magnetic gluon propagator\nand the color antisymmetric ghost propagator are affected by the presence of\ndynamical quarks and there are strong non-perturbative effects through the\ntemperature dependent color anti-symmetric ghost propagator."
    },
    {
        "anchor": "Vector Correlators in Lattice QCD: methods and applications: We discuss the calculation of the leading hadronic vacuum polarization in\nlattice QCD. Exploiting the excellent quality of the compiled experimental data\nfor the e^+e^- --> hadrons cross-section, we predict the outcome of\nlarge-volume lattice calculations at the physical pion mass, and design\ncomputational strategies for the lattice to have an impact on important\nphenomenological quantities such as the leading hadronic contribution to\n(g-2)mu and the running of the electromagnetic coupling constant. First, the\nR(s) ratio can be calculated directly on the lattice in the threshold region,\nand we provide the formulae to do so with twisted boundary conditions. Second,\nthe current correlator projected onto zero spatial momentum, in a Euclidean\ntime interval where it can be calculated accurately, provides a potentially\ncritical test of the experimental R(s) ratio in the region that is most\nrelevant for (g-2)mu. This observation can also be turned around: the vector\ncorrelator at intermediate distances can be used to determine the lattice\nspacing in fm, and we make a concrete proposal in this direction. Finally, we\nquantify the finite-size effects on the current correlator coming from\nlow-energy two-pion states and provide a general parametrization of the vacuum\npolarization on the torus.",
        "positive": "Lattice Models of Random Geometries: We review models of random geometries based on the dynamical lattice\napproach. We discuss one dimensional model of simplicial complexes (branched\npolymers), two dimensional model of dynamical triangulations and four\ndimensional model of simplicial gravity."
    },
    {
        "anchor": "Transverse spin structure of the nucleon from lattice QCD simulations: We present the first calculation in lattice QCD of the lowest two moments of\ntransverse spin densities of quarks in the nucleon. They encode correlations\nbetween quark spin and orbital angular momentum. Our dynamical simulations are\nbased on two flavors of clover-improved Wilson fermions and Wilson gluons. We\nfind significant contributions from certain quark helicity flip generalized\nparton distributions, leading to strongly distorted densities of transversely\npolarized quarks in the nucleon. In particular, based on our results and recent\narguments by Burkardt [Phys. Rev. D 72 (2005) 094020], we predict that the\nBoer-Mulders-function $h_1^\\perp$, describing correlations of transverse quark\nspin and intrinsic transverse momentum of quarks, is large and negative for\nboth up and down quarks.",
        "positive": "Measurement of hybrid content of heavy quarkonia using lattice NRQCD: Using lowest-order lattice NRQCD to create heavy meson propagators and\napplying the spin-dependent interaction, $c_B^{}\n\\frac{-g}{2m_q}\\vec\\sigma\\cdot\\vec{B}$, at varying intermediate time slices, we\ncompute the off-diagonal matrix element of the Hamiltonian for the\nquarkonium-hybrid two-state system. Thus far, we have results for one set of\nquenched lattices with an interpolation in quark mass to match the bottomonium\nspectrum. After diagonalization of the two-state Hamiltonian, we find the\nground state of the $\\Upsilon$ to show a $0.0035(1)c_B^2$ (with $c_B^2 \\sim\n1.5-3.1$) probability admixture of hybrid, $|b\\bar{b}g>$."
    },
    {
        "anchor": "Critical Behaviour in the Single Flavor Thirring Model in 2+1d: Results of a lattice field theory simulation of the single-flavor Thirring\nmodel in 2+1 spacetime dimensions are presented. The lattice model is\nformulated using domain wall fermions as a means to recover the correct U(2)\nsymmetries of the continuum model in the limit where wall separation\n$L_s\\to\\infty$. Simulations on $12^3, 16^3\\times L_s$, varying self-interaction\nstrength $g^2$ and bare mass $m$ are performed with $L_s = 8, \\ldots 48$, and\nthe results for the bilinear condensate $\\langle\\bar\\psi\\psi\\rangle$ fitted to\na model equation of state assuming a U(2)$\\to$U(1)$\\otimes$U(1)\nsymmetry-breaking phase transition at a critical $g_c^2$. First estimates for\n$g^{-2}a$ and critical exponents are presented, showing small but significant\ndepartures from mean-field values. The results confirm that a symmetry-breaking\ntransition does exist and therefore the critical number of flavors for the\nThirring model $N_c > 1$. Results for both condensate and associated\nsusceptibility are also obtained in the broken phase on $16^3\\times48$,\nsuggesting that here the $L_s\\to\\infty$ extrapolation is not yet under control.\nWe also present results obtained with the associated 2+1$d$ truncated overlap\noperator DOL demonstrating exponential localisation, a necessary condition for\nthe recovery of U(2) global symmetry, but that recovery of the Ginsparg-Wilson\ncondition as $L_s\\to\\infty$ is extremely slow in the broken phase.",
        "positive": "B-physics from the ratio method with Wilson twisted mass fermions: We present a precise lattice QCD determination of the b-quark mass, of the B\nand Bs decay constants and first preliminary results for the B-mesons bag\nparameter. Simulations are performed with Nf = 2 Wilson twisted mass fermions\nat four values of the lattice spacing and the results are extrapolated to the\ncontinuum limit. Our calculation benefits from the use of improved\ninterpolating operators for the B-mesons and employs the so-called ratio\nmethod. The latter allows a controlled interpolation at the b-quark mass\nbetween the relativistic data around and above the charm quark mass and the\nexactly known static limit."
    },
    {
        "anchor": "Monte Carlo Simulation of 2-D Quantum Gravity as Open Dynamically\n  Triangulate Random Surfaces: We describe a Monte Carlo procedure for the simulation of dynamically\ntriangulate random surfaces with a boundary (topology of a disk). The algorithm\nkeeps the total number of triangles fixed, while the length of the boundary is\nallowed to fluctuate. The algorithm works in the presence of matter fields. We\nhere present results for the pure gravity case. The algorithm reproduces the\ntheoretical expectations.",
        "positive": "Non-Reversibility of Molecular Dynamics Trajectories: We study the non-reversibility of molecular dynamics trajectories arising\nfrom the amplification of rounding errors. We analyse the causes of such\nbehaviour and give arguments, indicating that this does not pose a significant\nproblem for Hybrid Monte Carlo computations. We present data for pure SU(3)\ngauge theory and for QCD with dynamical fermions on small lattices to\nillustrate and to support some of our ideas."
    },
    {
        "anchor": "Heavy-light physics with NRQCD: First results are obtained for B mesons using a heavy propagator calculated\nusing NRQCD, and a light Wilson propagator. Results from 13 quenched\nconfigurations of size 16^3 x 48 at \\beta = 6.0 give a value for f_{B} of less\nthan 200 Mev and a B^{*}-B splitting of 32(8) MeV. Superior signal/noise\nbehaviour is observed over static propagators on the same configurations. No\nextrapolation to the b mass for the heavy quark is required.",
        "positive": "Path optimization method for the sign problem: We propose a path optimization method (POM) to evade the sign problem in the\nMonte-Carlo calculations for complex actions. Among many approaches to the sign\nproblem, the Lefschetz-thimble path-integral method and the complex Langevin\nmethod are promising and extensively discussed. In these methods, real field\nvariables are complexified and the integration manifold is determined by the\nflow equations or stochastically sampled. When we have singular points of the\naction or multiple critical points near the original integral surface, however,\nwe have a risk to encounter the residual and global sign problems or the\nsingular drift term problem. One of the ways to avoid the singular points is to\noptimize the integration path which is designed not to hit the singular points\nof the Boltzmann weight. By specifying the one-dimensional integration-path as\n$z=t+if(t) (f\\in \\mathbb{R})$ and by optimizing $f(t)$ to enhance the average\nphase factor, we demonstrate that we can avoid the sign problem in a\none-variable toy model for which the complex Langevin method is found to fail.\nIn this proceedings, we propose POM and discuss how we can avoid the sign\nproblem in a toy model. We also discuss the possibility to utilize the neural\nnetwork to optimize the path."
    },
    {
        "anchor": "Hadron Properties with FLIC Fermions: The Fat-Link Irrelevant Clover (FLIC) fermion action provides a new form of\nnonperturbative O(a)-improvement in lattice fermion actions offering near\ncontinuum results at finite lattice spacing. It provides computationally\ninexpensive access to the light quark mass regime of QCD where chiral\nnonanalytic behaviour associated with Goldstone bosons is revealed. The\nmotivation and formulation of FLIC fermions, its excellent scaling properties\nand its low-lying hadron mass phenomenology are presented.",
        "positive": "Perturbation Calculation of the Axial Anomaly of a Ginsparg-Wilson\n  lattice Dirac operator: A recent proposal suggests that even if a Ginsparg-Wilson lattice Dirac\noperator does not possess any topological zero modes in\ntopologically-nontrivial gauge backgrounds, it can reproduce correct axial\nanomaly for sufficiently smooth gauge configurations, provided that it is\nexponentially-local, doublers-free, and has correct continuum behavior. In this\npaper, we calculate the axial anomaly of this lattice Dirac operator in weak\ncoupling perturbation theory, and show that it recovers the topological charge\ndensity in the continuum limit."
    },
    {
        "anchor": "The Charm Quark on the Lattice: We formulate lattice fermions in a way that encompasses Wilson fermions as\nwell as the static and non-relativistic approximations. In particular, we treat\n$m_qa$ systematically ($m_q$ is the fermion mass) showing how to understand the\nWilson action as an effective action for systems with $\\vek{p}\\ll m_q$. The\nresults show how to extract matrix elements and the spectrum from simulations\nwith $m_qa\\approx1$, which is relevant for the charm quark.",
        "positive": "Neutral Meson Decays into Two Photons from Lattice QCD: A precision determination of the neutral-pion width would improve\ndeterminations of the splitting between the up- and down-quark masses, and\nmatrix elements for the decay of neutral mesons into two photons could play a\nrole in the attempt to probe beyond-the-Standard Model physics in muon $g-2$\nexperiments. The theoretical error is dominated by hadronic light-by-light\ndiagrams, and since direct measurements are extremely difficult, model\ncalculations factorize it into two-photon diagrams connected by the lightest\nhadrons. We employ perturbative techniques to express the photon as a\nsuperposition of QCD eigenstates accessible in lattice-QCD calculations and\nfound that vector-meson dominance is a poor description of the two-photon decay\nprocess when both photons are off shell."
    },
    {
        "anchor": "Recent progress in lattice supersymmetry: from lattice gauge theory to\n  black holes: Supersymmetry (SUSY) is a fascinating topic in theoretical physics, because\nof its unique and counterintuitive properties. It is expected to emerge as new\nphysics beyond the standard model, and it is also a building block for\nsupergravity and superstring theory. A number of exact results obtained via\nSUSY theories provide insights into field theory. However, the dynamics of many\nSUSY theories are not yet fully understood, and numerical study of SUSY\ntheories through lattice simulations is promising as regards furthering this\nunderstanding. In this paper, I overview the current status of lattice SUSY by\ndiscussing its development in chronological order, and by reviewing some simple\nmodels. In addition, I discuss the numerical verification of gauge/gravity\nduality, which is one of the recent significant developments in this field.",
        "positive": "Lattice QCD study of the heavy-heavy-light quark potential: We study the heavy-heavy-light quark ($QQq$) potential in SU(3) quenched\nlattice QCD, and discuss one of the roles of the finite-mass valence quark in\nthe inter-quark potential. Monte Carlo simulations are performed with the\nstandard gauge action on the $16^4$ lattice at $\\beta =6.0$ and the\n$O(a)$-improved Wilson fermion action at four hopping parameters. For\nstatistical improvement, the gauge configuration is fixed with the Coulomb\ngauge. We calculate the potential energy of $QQq$ systems as a function of the\ninter-heavy-quark distance $R$ in the range of $R \\le$ 0.8 fm. The $QQq$\npotential is well described with a Coulomb plus linear potential, and the\neffective string tension between the two heavy quarks is significantly smaller\nthan the string tension $\\sigma \\simeq 0.89$ GeV/fm. It would generally hold\nthat the effect of the finite-mass valence quark reduces the inter-two-quark\nconfinement force in baryons."
    },
    {
        "anchor": "Predictions and recent results in susy on the lattice: In this brief review, I summarize the current theoretical knowledge in\nsupersymmetry on the lattice, with special emphasis on recent results in the\nframework of N=1 supersymmetric Yang Mills theory, Wess-Zumino model and\nYang-Mills theory with extended supersymmetries.",
        "positive": "Anisotropy of the quark-antiquark potential in a magnetic field: We investigate the static $\\overline{Q}Q$-potential for $N_f = 2+1$ QCD at\nthe physical point in the presence of a constant and uniform external magnetic\nfield. The potential is found to be anisotropic and steeper in the directions\ntransverse to the magnetic field than in the longitudinal one. In particular,\nwhen compared to the standard case with zero background field, the string\ntension increases (decreases) in the transverse (longitudinal) direction, while\nthe absolute value of the Coulomb coupling and the Sommer parameter show an\nopposite behavior."
    },
    {
        "anchor": "The QCD phase diagram in the limit of heavy quarks using complex\n  Langevin dynamics: Complex Langevin simulations allow numerical studies of theories that exhibit\na sign problem, such as QCD, and are thereby potentially suitable to determine\nthe QCD phase diagram from first principles. Here we study QCD in the limit of\nheavy quarks for a wide range of temperatures and chemical potentials. Our\nresults include an analysis of the adaptive gauge cooling technique, which\nprevents large excursions into the non-compact directions of the SL($3,\n\\mathbb{C}$) manifold. We find that such excursions may appear spontaneously\nand change the statistical distribution of physical observables, which leads to\ndisagreement with known results. Results whose excursions are sufficiently\nsmall are used to map the boundary line between confined and deconfined quark\nphases.",
        "positive": "Decuplet Baryon Structure from Lattice QCD: The electromagnetic properties of the SU(3)-flavor baryon decuplet are\nexamined within a lattice simulation of quenched QCD. Electric charge radii,\nmagnetic moments, and magnetic radii are extracted from the E0 and M1 form\nfactors. Preliminary results for the E2 and M3 moments are presented giving the\nfirst model independent insight to the shape of the quark distribution in the\nbaryon ground state. As in our octet baryon analysis, the lattice results give\nevidence of spin-dependent forces and mass effects in the electromagnetic\nproperties. The quark charge distribution radii indicate these effects act in\nopposing directions. Some baryon dependence of the effective quark magnetic\nmoments is seen. However, this dependence in decuplet baryons is more subtle\nthan that for octet baryons. Of particular interest are the lattice predictions\nfor the magnetic moments of $\\Omega^-$ and $\\Delta^{++}$ for which new recent\nexperimental measurements are available. The lattice prediction of the\n$\\Delta^{++}/p$ ratio appears larger than the experimental ratio, while the\nlattice prediction for the $\\Omega^-/p$ magnetic moment ratio is in good\nagreement with the experimental ratio."
    },
    {
        "anchor": "Investigation of complex $\u03c6^{4}$ theory at finite density in two\n  dimensions using TRG: We study the two-dimensional complex $\\phi^{4}$ theory at finite chemical\npotential using the tensor renormalization group. This model exhibits the\nSilver Blaze phenomenon in which bulk observables are independent of the\nchemical potential below the critical point. Since it is expected to be a\ndirect outcome of an imaginary part of the action, an approach free from the\nsign problem is needed. We study this model systematically changing the\nchemical potential in order to check the applicability of the tensor\nrenormalization group to the model in which scalar fields are discretized by\nthe Gaussian quadrature. The Silver Blaze phenomenon is successfully confirmed\non the extremely large volume $V=1024^2$ and the results are also ensured by\nanother tensor network representation with a character expansion.",
        "positive": "Lattice QCD Methods for Hadronic Polarizabilities: Chiral dynamics makes definitive predictions for the electromagnetic\npolarizabilities of hadrons near the chiral limit; but, agreement with\nexperiment is tenuous in some cases. We provide an overview of lattice QCD\nmethods to compute the electric and magnetic polarizabilities of hadrons.\nCentral to these methods is the lattice simulation of quarks in uniform,\nclassical electromagnetic fields. A long-term goal is the determination of\npolarizabilities directly from lattice computations, however, in the near term,\none may need to rely on partially quenched chiral perturbation theory.\nNonetheless the same striking predictions for the pion mass dependence of\nelectric and magnetic polarizabilities can be made from chiral dynamics, and\ntested with lattice QCD. A particular focus is a novel new method to handle\ncharged particle correlation functions in magnetic fields."
    },
    {
        "anchor": "Low-lying eigenmodes of the Wilson-Dirac operator and correlations with\n  topological objects: The probability density of low-lying eigenvectors of the hermitian\nWilson-Dirac operator is examined. Comparisons in position and size between\neigenvectors, topological charge and action density are made. We do this for\nstandard Monte-Carlo generated SU(3) background fields and for single instanton\nbackground fields. Both hot and cooled SU(3) background fields are considered.\nAn instanton model is fitted to eigenmodes and topological charge density and\nthe sizes and positions of these are compared.",
        "positive": "Quark condensate in two-flavor QCD: We compute the condensate in QCD with two flavors of dynamical fermions using\nnumerical simulation. The simulations use overlap fermions, and the condensate\nis extracted by fitting the distribution of low lying eigenvalues of the Dirac\noperator in sectors of fixed topological charge to the predictions of Random\nMatrix Theory."
    },
    {
        "anchor": "Axial Magnetic Effect and Chiral Vortical Effect with free lattice\n  chiral fermions: Following the recent work by Braguta et al., we perform an indirect\ncalculation of the chiral vortical conductivity with free lattice overlap\nfermions by measuring the response of the energy flow to the constant axial\nmagnetic field. We find that the measurements are contaminated by very large\nfinite-volume artifacts. However, the continuum result for finite-temperature\ncontribution to the chiral vortical conductivity (T^2/12) is still reproduced\nin the limit of infinite volume at fixed temperature.",
        "positive": "Lattice Perturbation Theory in Noncommutative Geometry and Parity\n  Anomaly in 3D Noncommutative QED: We formulate lattice perturbation theory for gauge theories in noncommutative\ngeometry. We apply it to three-dimensional noncommutative QED and calculate the\neffective action induced by Dirac fermions. In particular \"parity invariance\"\nof a massless theory receives an anomaly expressed by the noncommutative\nChern-Simons action. The coefficient of the anomaly is labelled by an integer\ndepending on the lattice action, which is a noncommutative counterpart of the\nphenomenon known in the commutative theory. The parity anomaly can also be\nobtained using Ginsparg-Wilson fermions, where the masslessness is guaranteed\nat finite lattice spacing. This suggests a natural definition of the\nlattice-regularized Chern-Simons theory on a noncommutative torus, which could\nenable nonperturbative studies of quantum Hall systems."
    },
    {
        "anchor": "Strange and charm contributions to the HVP from C* boundary conditions: We present preliminary results for the determination of the leading strange\nand charm quark-connected contributions to the hadronic vacuum polarization\ncontribution to the muon's g-2. Measurements are performed on the RC*\ncollaboration's QCD ensembles, with 3+1 flavors of O(a) improved Wilson\nfermions and C* boundary conditions. The HVP is computed on a single value of\nthe lattice spacing and two lattice volumes at unphysical pion mass. In\naddition, we compare the signal-to-noise ratio for different lattice\ndiscretizations of the vector current.",
        "positive": "Study of Hadron Scattering Using an Asymmetric Box: We propose to study hadron-hadron scattering using lattice QCD in an\nasymmetric box which allows one to access more non-degenerate low-momentum\nmodes for a given volume. The conventional L\\\"{u}scher's formula applicable in\na symmetric box is modified accordingly. To illustrate the feasibility of this\napproach, pion-pion elastic scattering phase shifts in the I=2, J=0 channel are\ncalculated within quenched approximation using improved gauge and Wilson\nfermion actions on anisotropic lattices in an asymmetric box. After the chiral\nand continuum extrapolation, we find that our quenched results for the\nscattering phase shifts in this channel are consistent with the experimental\ndata when the three-momentum of the pion is below 300MeV. Agreement is also\nfound when compared with previous theoretical results from lattice and other\nmeans. Moreover, with the usage of asymmetric volume, we are able to compute\nthe scattering phases in the low-momentum range (pion three momentum less than\nabout 350MeV in the center of mass frame) for over a dozen values of the pion\nthree-momenta, much more than using the conventional symmetric box with\ncomparable volume."
    },
    {
        "anchor": "A Lower Bound on $T_{SR}/{m_{\\rm H}}$ in the O(4) Model on Anisotropic\n  Lattices: Results of an investigation of the $O(4)$ spin model at finite temperature\nusing anisotropic lattices are presented. In both the large $N$ approximation\nand numerical simulations using the Wolff cluster algorithm we find that the\nratio of the symmetry restoration temperature $T_{\\rm SR}$ to the Higgs mass\n$m_{\\rm H}$ is independent of the anisotropy $\\xi$. From the numerical\nsimulations we obtain a lower bound of $T_{\\rm SR} / m_{\\rm H} \\simeq 0.58 \\pm\n0.02$ at a value for the Higgs mass $m_{\\rm H}a_s \\simeq 0.5$, which is lowered\nfurther by about $10\\%$ at $m_{\\rm H}a_s \\simeq 1$. Requiring certain timelike\ncorrelation functions to coincide with their spacelike counterparts, quantum\nand scaling corrections to the anisotropy are determined and are found to be\nsmall, i.e., the anisotropy is found to be close to the ratio of spacelike and\ntimelike lattice spacings.",
        "positive": "K^0-\\bar{K}^0 Mixing Beyond the SM from Nf=2 tmQCD: We present preliminary results on the of neutral kaon oscillations in\nextensions of the Standard Model. Using Nf=2 maximally twisted sea quarks and\nOsterwalder-Seiler valence quarks, we achieve both O(a)-improvement and\ncontinuum-like renormalization pattern for the relevant four-fermion operators.\nWe perform simulations at three values of the lattice spacing and\nextrapolate/interpolate our results to the continuum limit and physical\nlight/strange quark mass. The calculation of the renormalization constants of\nthe complete operator basis is performed non- perturbatively in the RI-MOM\nscheme."
    },
    {
        "anchor": "Worm algorithm for the O(2N) Gross-Neveu model: We study the lattice O(2N) Gross-Neveu model with Wilson fermions in the\nfermion loop formulation. Employing a worm algorithm for an open fermionic\nstring, we simulate fluctuating topological boundary conditions and use them to\ntune the system to the critical point. We show how the worm algorithm can be\nextended to sample correlation functions of bound states involving an arbitrary\nnumber of Majorana fermions and present first results.",
        "positive": "A Monte Carlo study of old, new and tadpole improved actions: Scaling of mass ratios in intermediate volumes, obtained with improved SU(2)\nlattice actions is tested against analytic results for the Wilson and continuum\naction. A new improved action is introduced by adding a 2X2 plaquette to the\nSymanzik action. Completing a square leads to a covariant propagator that\nsimplifies perturbative calculations. Data is presented on lattices of size\n4**3X128, with lattice spacings of approximately 0.02 and 0.12 fermi. For the\nlatter case no further improvement as compared to the tree-level action was\nobserved when including the Lepage-Mackenzie tadpole correction to the one-loop\nimproved Luscher-Weisz Symanzik action."
    },
    {
        "anchor": "The Upsilon spectrum and m_b from full lattice QCD: We show results for the Upsilon spectrum calculated in lattice QCD including\nfor the first time vacuum polarization effects for light u and d quarks as well\nas s quarks. We use gluon field configurations generated by the MILC\ncollaboration. The calculations compare the results for a variety of u and d\nquark masses, as well as making a comparison to quenched results (in which\nquark vacuum polarisation is ignored) and results with only u and d quarks. The\nb quarks in the Upsilon are treated in lattice Nonrelativistic QCD through NLO\nin an expansion in the velocity of the b quark. We concentrate on accurate\nresults for orbital and radial splittings where we see clear agreement with\nexperiment once u, d and s quark vacuum polarisation effects are included. This\nnow allows a consistent determination of the parameters of QCD. We demonstrate\nthis consistency through the agreement of the Upsilon and B spectrum using the\nsame lattice bare b quark mass. A one-loop matching to continuum QCD gives a\nvalue for the b quark mass in full lattice QCD for the first time. We obtain\nm_b^{\\bar{MS}}(m_b^{\\bar{MS}}) = 4.4(3) GeV. We are able to give physical\nresults for the heavy quark potential parameters, r_0 = 0.469(7) fm and r_1 =\n0.321(5) fm. Results for the fine structure in the spectrum and the Upsilon\nleptonic width are also presented. We predict the Upsilon - eta_b splitting to\nbe 61(14) MeV, the Upsilon^{\\prime} - eta_b^{\\prime} splitting as 30(19) MeV\nand the splitting between the h_b and the spin-average of the chi_b states to\nbe less than 6 MeV. Improvements to these calculations that will be made in the\nnear future are discussed.",
        "positive": "Basis States for Hamiltonian QCD with Dynamical Quarks: We discuss the construction of basis states for Hamiltonian QCD on the\nlattice, in particular states with dynamical quark pairs. We calculate the\nmatrix elements of the operators in the QCD Hamiltonian between these states.\nAlong with the ``harmonic oscillator'' states introduced in previous pure SU(3)\nwork, these states form a working basis for calculations in full QCD."
    },
    {
        "anchor": "Axial and tensor charge of the nucleon with dynamical fermions: We present preliminary results for the axial and tensor charge of the nucleon\nobtained from simulations with N_f=2 clover fermions. A comparison with chiral\nperturbation theory is attempted.",
        "positive": "Two Meson Systems with Ginsparg-Wilson Valence Quarks: Unphysical effects associated with finite lattice spacing and partial\nquenching may lead to the presence of unphysical terms in chiral extrapolation\nformulae. These unphysical terms must then be removed during data analysis\nbefore physical predictions can be made. In this work, we show that through\nnext-to-leading order, there are no unphysical counterterms in the\nextrapolation formulae, expressed in lattice-physical parameters, for meson\nscattering lengths in theories with Ginsparg-Wilson valence quarks. Our work\napplies to most sea quark discretization, provided that chiral perturbation\ntheory is a valid approximation. We demonstrate our results with explicit\ncomputations and show that, in favorable circumstances, the extrapolation\nformulae do not depend on the unknown constant C_Mix appearing at lowest order\nin the mixed action chiral Lagrangian. We show that the I=1 KK scattering\nlength does not depend on C_Mix in contrast to the I=3/2 K-pi scattering\nlength. In addition, we show that these observables combined with f_K / f_pi\nand the I=2 pi-pi scattering length share only two linearly independent sets of\ncounterterms, providing a means to test the mixed action theory at one lattice\nspacing. We therefore make a prediction for the I=1 KK scattering length."
    },
    {
        "anchor": "Localization of Dirac modes in finite-temperature $\\mathbb{Z}_2$ gauge\n  theory on the lattice: We study the localization properties of the eigenmodes of the staggered Dirac\noperator in finite-temperature $\\mathbb{Z}_2$ pure gauge theory on the lattice\nin 2+1 dimensions. We find that the low modes turn from delocalized to\nlocalized as the system crosses over from the confined to the deconfined phase\nin the \"physical\" sector (positive average Polyakov loop) selected by external\nfermionic probes, while they remain delocalized in the \"unphysical\" sector\n(negative average Polyakov loop). This confirms that the close connection\nbetween deconfinement and localization of the low Dirac modes in the physical\nsector, already observed in other models, holds also in the simplest gauge\ntheory displaying a deconfinement transition. We also observe a clear\ncorrelation of localized modes with fluctuations of the Polyakov loop away from\nthe ordered value, as expected according to the \"sea/islands\" picture of\nlocalization, and with clusters of negative plaquettes. A novel finding is the\npresence of localized modes at the high end of the Dirac spectrum in all\nphases/sectors of the theory.",
        "positive": "Flavor-Symmetry Restoration and Symanzik Improvement for Staggered\n  Quarks: We resolve contradictions in the literature concerning the origins and size\nof unphysical flavor-changing strong interactions generated by the\nstaggered-quark discretization of QCD. We show that the leading contributions\nare tree-level in $\\order(a^2)$ and that they can be removed by adding three\ncorrection terms to the link operator in the standard action. These corrections\nare part of the systematic Symanzik improvement of the staggered-quark action.\nWe present a new improved action for staggered quarks that is accurate up to\nerrors of $\\order(a^4,a^2\\alpha_s)$ --- more accurate than most, if not all,\nother discretizations of light-quark dynamics."
    },
    {
        "anchor": "An Exact Local Hybrid Monte Carlo Algorithm for Gauge Theories: We introduce a new Monte Carlo method for pure gauge theories. It is not\nintended for use with dynamical fermions. It belongs to the class of Local\nHybrid Monte Carlo (LHMC) algorithms, which make use of the locality of the\naction by updating individual sites or links by following a classical mechanics\ntrajectory in fictitious time. We choose to update a one-parameter subgroup of\nthe gauge field on each link of the lattice, and the classical trajectory can\nbe found in closed form in terms of elliptic functions for this case. We show\nthat this gives an overrelaxation algorithm with a tunable parameter which,\nunlike some previous methods, does not require the numerical integration of the\nequations of motion.",
        "positive": "Preliminary lattice study of $\u03c3$ meson decay width: We report an exploratory lattice investigation of $\\sigma$ meson decay width\nusing s-wave scattering phase for isospin I=0 pion-pion ($\\pi\\pi$) system.\nRummukainen-Gottlieb formula is used to estimate the scattering phase, which\ndemonstrate the presence of a resonance around $\\sigma$ meson. Using the\neffective range formula we extract the effective $\\sigma \\to \\pi\\pi$ coupling\nconstant as $g_{\\sigma \\pi\\pi} = 2.69(44)$ GeV, which is consistent with\ntheoretical predictions. The estimated decay width is about $236 \\pm 49$ MeV.\nThese simulations are carried out on a $16^3\\times48$ MILC gauge configuration\nwith the $N_f=2+1$ flavor of the \"Asqtad\" improved staggered dynamical sea\nquarks at $ m_\\pi / m_\\sigma \\approx 0.414$ and the lattice spacing $a \\approx\n0.15$ fm."
    },
    {
        "anchor": "The Overlap Dirac Operator: This introductory presentation describes the Overlap Dirac Operator, why it\ncould be useful in numerical QCD, and how it can be implemented.",
        "positive": "GW Meson Scattering on a Staggered Sea: We discuss the structure of the NLO corrections to the chiral formulae for\nmesonic scattering processes in mixed action simulations using Ginsparg-Wilson\nvalence quarks and staggered sea quarks. In particular, we show that the\nanalytic contribution of the NLO chiral Lagrangian is the same as in QCD. We\nalso comment on how this result restricts the dependence of the amplitudes on\nthe unknown parameter C_Mix appearing in the chiral theory appropriate for\nthese systems. We conclude with some comments on the explicit scattering\nlengths."
    },
    {
        "anchor": "On the Absence of an Exponential Bound in Four Dimensional Simplicial\n  Gravity: We have studied a model which has been proposed as a regularisation for four\ndimensional quantum gravity. The partition function is constructed by\nperforming a weighted sum over all triangulations of the four sphere. Using\nnumerical simulation we find that the number of such triangulations containing\n$V$ simplices grows faster than exponentially with $V$. This property ensures\nthat the model has no thermodynamic limit.",
        "positive": "Determination of the strange nucleon form factors: The strange contribution to the electric and magnetic form factors of the\nnucleon is determined at a range of discrete values of $Q^2$ up to $1.4$\nGeV$^2$. This is done by combining recent lattice QCD results for the\nelectromagnetic form factors of the octet baryons with experimental\ndeterminations of those quantities. The most precise result is a small negative\nvalue for the strange magnetic moment: $G_M^s(Q^2=0) = -0.07\\pm0.03\\,\\mu_N$. At\nlarger values of $Q^2$ both the electric and magnetic form factors are\nconsistent with zero to within $2$-sigma."
    },
    {
        "anchor": "Highly-improved lattice field-strength tensor: We derive an O(a^4)-improved lattice version of the continuum field-strength\ntensor. Discretization errors are reduced via the combination of several clover\nterms of various sizes, complemented by tadpole improvement. The resulting\nimproved field-strength tensor is used to construct O(a^4)-improved topological\ncharge and action operators. We compare the values attained by these operators\nas we cool several configurations to self-duality with a previously defined\nhighly-improved action and assess the relative scale of the remaining\ndiscretization errors.",
        "positive": "Nucleon and Pion Form Factors from $N_f=2+1$ Anisotropic Lattices: We report a recent lattice-QCD calculation of nucleon and pion\nelectromagnetic form factors and nucleon axial form factors, with special\nemphasis on large $Q^2$. Conventional lattice form-factor calculations can only\nreach about 2.5 GeV$^2$, but in this work the transfer momentum is pushed as\nlarge as 6 GeV$^2$. Here, we demonstrate the results on 2+1-flavor anisotropic\nclover lattices for the nucleon and pion, comparing with low-$Q^2$ quantities,\nsuch as Dirac and Pauli radii, anomalous magnetic moments, $g_A$ and $M_A$. Our\napproach can be applied to isotropic lattices and lattices with smaller lattice\nspacing to achieve even larger-$Q^2$ form factors. The form factors are\nprocessed to obtain transverse charge and magnetization densities across\n2-dimensional impact-parameter space. These measurements could give important\ntheoretical input to experiments, such as those of JLab's 12-GeV program, and\nprovide insight into hadronic structure."
    },
    {
        "anchor": "Quantum chaos in supersymmetric Yang-Mills-like model: equation of\n  state, entanglement, and spectral form-factors: We analyze in detail a sharp transition between the low-energy,\nlow-dimensional eigenstates and the high-energy chaotic bulk of the spectrum\nfor a simple supersymmetric quantum-mechanical model with Hamiltonian\n$\\hat{H}_S = \\left(\\hat{p}_1^2 + \\hat{p}_2^2 + \\hat{x}_1^2 \\, \\hat{x}_2^2\n\\right) \\otimes I + \\hat{x}_1 \\otimes \\sigma_1 + \\hat{x}_2 \\otimes \\sigma_3$,\nwhich mimics the structure of the Banks-Fischler-Susskind-Stanford (BFSS)\nmatrix model, the spatially compactified $\\mathcal{N} = 1$ super-Yang-Mills\ntheory. We conjecture that this transition might be similar to the transition\nbetween the $D0$-brane and $M$-theory regimes in the BFSS model, and find that\nit does not lead to irregularities in the thermodynamic equation of state. We\ndemonstrate that real-time spectral form-factor for our supersymmetric model\nexhibits the ``ramp'' behavior typical for quantum chaos. We also analyze the\nentanglement entropy and the spectrum of the reduced density matrix of the\neigenstates of $\\hat{H}_S$, considering one of the bosonic degrees of freedom\nas a subsystem. The entanglement entropy of low-energy eigenstates appears to\nbe practically energy-independent. Exactly at the onset of random-matrix-type\nlevel spacing fluctuations, this behavior rapidly changes into a steady growth\nof entanglement with energy. We demonstrate that the spectrum of the reduced\ndensity matrix also exhibits universal level-spacing fluctuations towards its\nhigher end, even for the ground state of the supersymmetric model. Thus even\nthe regularly spaced, non-chaotic eigenstates contain some information about\nsemi-classical chaotic dynamics at high energies.",
        "positive": "Baryon resonances coupled to Pion-Nucleon states in lattice QCD: In recent years the study of two particle systems on the lattice has led to\nexcellent results in the meson sector of the QCD spectrum, however baryon\nresonances mostly remain unexplored. We present a study of pion-nucleon systems\nas decay product of baryon resonances in different channels, with special focus\non the nucleon spectrum. We evaluate the correlation functions of single and\nmulti particle interpolators. All the Wick contributions are explicitly\ncomputed and the consequences of reduced symmetries in moving frames are taken\ninto account. We discuss the theoretical setup together with results for\n$n_f=2$ mass degenerate light quarks."
    },
    {
        "anchor": "Xtoys: cellular automata on xwindows: Xtoys is a collection of xwindow programs for demonstrating simulations of\nvarious statistical models. Included are xising, for the two dimensional Ising\nmodel, xpotts, for the $q$-state Potts model, xautomalab, for a fairly general\nclass of totalistic cellular automata, xsand, for the Bak-Tang-Wiesenfield\nmodel of self organized criticality, and xfires, a simple forest fire\nsimulation. The programs should compile on any machine supporting xwindows.",
        "positive": "B_s-\\bar{B_s} mixing with a chiral light quark action: We study the $B^0_s-\\bar{B^0_s}$ mixing amplitude in Standard Model by\ncomputing the relevant hadronic matrix element in the static limit of lattice\nHQET with the Neuberger light quark action. In the quenched approximation, and\nafter matching to the $\\bar{\\rm MS}$ scheme in QCD, we obtain $B^{\\bar{\\rm\nMS}}_{B_s}(m_b)=0.940(16)(22)$."
    },
    {
        "anchor": "Finite volume corrections to forward Compton scattering off the nucleon: We calculate the spin-averaged amplitude for doubly virtual forward Compton\nscattering off nucleons in the framework of manifestly Lorentz invariant baryon\nchiral perturbation theory at complete one-loop order $O(p^4)$. The\ncalculations are carried out both in the infinite and in a finite volume. The\nobtained results allow for a detailed estimation the finite-volume corrections\nto the amplitude which can be extracted on the lattice using the background\nfield technique.",
        "positive": "Solutions of the Ginsparg-Wilson Relation: We analyze general solutions of the Ginsparg-Wilson relation for lattice\nDirac operators and formulate a necessary condition for such operators to have\nnon-zero index in the topologically nontrivial background gauge fields."
    },
    {
        "anchor": "Physical Effects of Infrared Quark Eigenmodes in LQCD: A truncated determinant algorithm is used to study the physical effects of\nthe quark eigenmodes associated with eigenvalues below 400 MeV. This initial\nstudy focuses on coarse lattices (with O(a^2) improved gauge action), light\ninternal quark masses and large physical volumes. Four bellwether full QCD\nprocesses are discussed: topological charge distributions, the eta prime\npropagator, string breaking as observed in the static energy and the rho decay\ninto two pions.",
        "positive": "Exploring Residual Gauge Symmetry Breaking: Simulations of pure-gauge SU(2) lattice gauge theory are performed in the\nminimal Coulomb gauge. This leaves a residual or remnant gauge symmetry still\nactive which is global in three directions but still local in one. Using\naveraged fourth-dimension pointing links as a spin-like order parameter, the\nremnant symmetry appears to undergo spontaneous symmetry breaking at around\n$\\beta = 2.6$. Both the Binder cumulant and the magnetization itself exhibit\ncrossings in this region using lattices up to $20^4$, and a susceptibility peak\nis also observed. Finite size scaling indicates a weak first-order transition.\nThe symmetry breaking is also observed to take place in the fundamental-adjoint\nplane, and is coincident with the strong first-order transition that exists\nthere at large $\\beta_{\\rm{adjoint}}$. This provides confirmation that this\nphase transition is a symmetry-breaking transition. A well-known theorem\nconcerning the instantaneous Coulomb potential has previously proven that a\ntransition where such a Coulomb-gauge remnant symmetry breaks is necessarily\ndeconfining."
    },
    {
        "anchor": "The critical region of strong-coupling lattice QCD in different large-N\n  limits: We study the critical behavior at nonzero temperature phase transitions of an\neffective Hamiltonian derived from lattice QCD in the strong-coupling\nexpansion. Following studies of related quantum spin systems that have a\nsimilar Hamiltonian, we show that for large $N_c$ and fixed $g^2N_c$, mean\nfield scaling is not expected, and that the critical region has a finite width\nat $N_c=\\infty$. A different behavior rises for $N_f\\to \\infty$ and fixed $N_c$\nand $g^2/N_f$, which we study in two spatial dimensions and for $N_c=1$. We\nfind that the width of the critical region is suppressed by $1/N_f^p$ with\n$p=1/2$, and argue that a generalization to $N_c>1$ and to three dimensions\nwill change this only in detail (e.g. the value of $p>0$), but not in\nprinciple. We conclude by stating under what conditions this suppression is\nexpected, and remark on possible realizations of this phenomenon in lattice\ngauge theories in the continuum.",
        "positive": "Isovector nucleon form factors from 2+1-flavor dynamical domain-wall\n  lattice QCD at the physical mass: Nucleon isovector form factors calculated on a 2+1-flavor\ndomain-wall-fermions ensemble with strange and degenerate up and down quarks at\nphysical mass and lattice cut off, $a^{-1}$, of about 1.730(4) GeV, are\nreported. The ensemble was generated jointly by RBC and UKQCD collaborations\nwith a spatial extent of $48a$ or about 5.5 fm. The form factors are calculated\nin collaboration with LHP collaboration as well. The resulting shape parameters\nof the form factors, such as vector-charge mean squared radius, $\\langle\nr_1^2\\rangle$, or anomalous magnetic moment, $F_2(0)$ appear less dependent on\npossible excited-state contaminations than the corresponding charges.\nPreliminary estimates are $\\langle r_1^2\\rangle \\sim 0.142(13)\\, \\mbox{fm}^2$\nand $F_2(0) \\sim 3.22(8)$."
    },
    {
        "anchor": "The present status of non-compact lattice QED: We give a 1993 update of non-compact lattice QED, in particular the chiral\ncondensate, finite size effects and meson mass ratios.\n  We compare descriptions of the phase transition. Our previous conclusions\nremain valid.",
        "positive": "Isospin 0 and 2 two-pion scattering at physical pion mass using\n  all-to-all propagators with periodic boundary conditions in lattice QCD: A study of two-pion scattering for the isospin channels, $I=0$ and $I=2$,\nusing lattice QCD is presented. M\\\"obius domain wall fermions on top of the\nIwasaki-DSDR gauge action for gluons with periodic boundary conditions are used\nfor the lattice computations which are carried out on two ensembles of gauge\nfield configurations generated by the RBC and UKQCD collaborations with\nphysical masses, inverse lattice spacings of 1.023 and 1.378 GeV, and spatial\nextents of $L=4.63$ and 4.58 fm, respectively. The all-to-all propagator method\nis employed to compute a matrix of correlation functions of two-pion operators.\nThe generalized eigenvalue problem (GEVP) is solved for a matrix of correlation\nfunctions to extract phase shifts with multiple states, two pions with a\nnon-zero relative momentum as well as two pions at rest. Our results for phase\nshifts for both $I=0$ and $I=2$ channels are consistent with and the Roy\nEquation and chiral perturbation theory, though at this preliminary stage our\nerrors for $I=0$ are large. An important outcome of this work is that we are\nsuccessful in extracting two-pion excited states, which are useful for studying\n$K\\to\\pi\\pi$ decay, on physical-mass ensembles using GEVP."
    },
    {
        "anchor": "Chiral behaviour of the lattice $B_K$-parameter with the Wilson and\n  Clover Actions at $\u03b2= 6.0$: We present results for the kaon $B$-parameter $B_K$ from a sample of $200$\nconfigurations using the Wilson action and $460$ configurations using the\nSW-Clover action, on a $18^3 \\times 64$ lattice at $\\beta=6.0$. We compare\nresults obtained by renormalizing the relevant operator with different\n``boosted\" values of the strong coupling constant $\\alpha_s$. In the case of\nthe SW-Clover action, we also use the operator renormalized non-perturbatively.\nIn the Wilson case, we observe a strong dependence of $B_K$ on the prescription\nadopted for $\\alpha_s$, contrary to the results of the Clover case which are\nalmost unaffected by the choice of the coupling. We also find that the matrix\nelement of the operator renormalized non-perturbatively has a better chiral\nbehaviour. This gives us our best estimate of the renormalization group\ninvariant $B$-parameter, $\\hat B_K=0.86 \\pm 0.15$.",
        "positive": "Schwinger model on an interval: analytic results and DMRG: Quantum electrodynamics in $1+1$ dimensions (Schwinger model) on an interval\nadmits lattice discretization with a finite-dimensional Hilbert space, and is\noften used as a testbed for quantum and tensor network simulations. In this\nwork we clarify the precise mapping between the boundary conditions in the\ncontinuum and lattice theories. In particular we show that the conventional\nGauss law constraint commonly used in simulations induces a strong boundary\neffect on the charge density, reflecting the appearance of fractionalized\ncharges. Further, we obtain by bosonization a number of exact analytic results\nfor local observables in the massless Schwinger model. We compare these\nanalytic results with the simulation results obtained by the density matrix\nrenormalization group (DMRG) method and find excellent agreements."
    },
    {
        "anchor": "Present and future prospects for lattice QCD calculations of matrix\n  elements for nEDM: A status report on the calculations of the contribution of four CP violating\noperators, the $\\Theta$-term, the quark EDM, the chromo EDM and the Weinberg\noperator to the neutron EDM are presented. At this time, there exit precise\nphysical results only for the quark EDM operator by the PNDME collaboration.\nFirst results showing signal in the contributions of the $\\Theta$-term and the\nconnected part of the chromo EDM operator have been presented. The challenge of\ndivergent mixing in the chromo EDM and Weinberg operators has motivated\ncalculations in the gradient flow scheme. While there has been steady progress,\nthe challenges remaining are large. Results with $O(50\\%)$ uncertainty with\ncontrol over all systematic errors can be expected for the $\\Theta$-term over\nthe next five years. Prediction of a timeline for progress on the chromo EDM\nand the Weinberg operators will depend on when the renormalization and\ndivergent mixing of these operators is brought under control. The most\noptimistic scenario is that the gradient flow scheme provides a solution to the\nnumerical signal and mixing problems for both the gluonic and quark operators.",
        "positive": "Improved cooling algorithm for gauge theories: We propose and study a ``gold-washing\" - type of algorithm which smooths out\nthe short range fluctuations but leaves invariant instantons above a certain\nsize. The algorithm needs no monitoring or calibration."
    },
    {
        "anchor": "Static quark anti-quark free energy and the running coupling at finite\n  temperature: We analyze the free energy of a static quark anti-quark pair in quenched QCD\nat short and large distances. From this we deduce running couplings, g^2(r,T),\nand determine the length scale that separates at high temperature the short\ndistance perturbative regime from the large distance non-perturbative regime in\nthe QCD plasma phase. Ambiguities in the definition of a coupling beyond the\nperturbative regime are discussed in their relation to phenomenological\nconsiderations on heavy quark bound states in the quark gluon plasma. Our\nanalysis suggests that it is more appropriate to characterize the\nnon-perturbative properties of the QCD plasma phase close to T_c in terms\nremnants of the confinement part of the QCD force rather than a strong\nCoulombic force.",
        "positive": "Towards a Dynamical Solution of the Strong CP Problem: It is argued that QCD might solve the strong CP problem on its own. To test\nthis idea, a lattice simulation suggests itself. In view of the difficulty of\nsuch a calculation we have, as a first step, investigated the problem in the\n$CP^3$ model. The $CP^3$ model is in many respects similar to QCD. In this talk\nI shall present some first results of our calculation. Among other things it is\nshown that the model has a first order deconfining phase transition in $\\theta$\nand that the critical value of $\\theta$ decreases towards zero as $\\beta$ is\ntaken to infinity. This suggests that $\\theta$ is tuned to zero in the\ncontinuum limit."
    },
    {
        "anchor": "SO(3) versus SU(2) lattice gauge theory: We consider the SO(3) lattice gauge theory at weak coupling, in the Villain\naction. We exhibit an analytic path in coupling space showing the equivalence\nof the SO(3) theory with SU(2) summed over all twist sectors. This clarifies\nthe ``mysterious phase'' of SO(3). As order parameter, we consider the dual\nstring tension or center vortex free energy, which we measure in SO(3) using\nmulticanonical Monte Carlo. This allows us to set the scale, indicating that\n${\\cal O}(700)^4$ lattices are necessary to probe the confined phase. We\nconsider the relevance of our findings for confinement in other gauge groups\nwith trivial center.",
        "positive": "Spin-taste structure of minimally doubled fermions: Minimally doubled fermions realize one degenerate pair of Dirac fermions on\nthe lattice. Similarities to staggered fermions exist, namely, spin and taste\ndegrees of freedom become intertwined, and a remnant, non-singlet chiral\nsymmetry and ultralocality are maintained. However, charge conjugation,\nisotropy and some space-time reflection symmetries are broken by the cutoff.\nFor two variants, i.e., Karsten-Wilczek (KW) or Borici-Creutz (BC) fermions, a\ntasted charge conjugation symmetry can be identified, and the respective\nrepresentations of the spin-taste algebra can be constructed explicitly. In the\ncase of BC fermions, the tasted symmetry indicates that amendments to the\npublished counterterms are necessary. The spin-taste representation on the\nquark level permits construction of local or extended hadron interpolating\noperators for any spin-taste combination, albeit with contamination by parity\npartners and taste-symmetry violation. The few available numerical results for\nKW fermions are in line with expectations."
    },
    {
        "anchor": "Inclusive semi-leptonic B meson decay structure functions from lattice\n  QCD: We propose a method to non-perturbatively calculate the forward-scattering\nmatrix elements relevant to inclusive semi-leptonic B meson decays.\nCorresponding hadronic structure functions at unphysical kinematics are\naccessible through lattice QCD calculation of four-point correlation functions.\nThe unphysical kinematical point may be reached by analytic continuation from\nthe physical differential decay rate. A numerical test is performed for the B_s\n-> X_c l nu mode in the zero-recoil limit. We use lattice ensembles generated\nwith 2+1 dynamical quark flavors. The valence charm quark mass is tuned to its\nphysical value, while the bottom quark mass is varied in the range\n(1.56-2.44)m_c. From the numerical results we can identify the contributions of\nthe ground state D_s^(*) meson as well as those of excited states or continuum\nstates.",
        "positive": "SPHERICALLY SYMMETRIC RANDOM WALKS II. DIMENSIONALLY DEPENDENT CRITICAL\n  BEHAVIOR: A recently developed model of random walks on a $D$-dimensional\nhyperspherical lattice, where $D$ is {\\sl not} restricted to integer values, is\nextended to include the possibility of creating and annihilating random\nwalkers. Steady-state distributions of random walkers are obtained for all\ndimensions $D>0$ by solving a discrete eigenvalue problem. These distributions\nexhibit dimensionally dependent critical behavior as a function of the birth\nrate. This remarkably simple model exhibits a second-order phase transition\nwith a nontrivial critical exponent for all dimensions $D>0$."
    },
    {
        "anchor": "Loop States in Lattice Gauge Theories: We solve the Gauss law as well as the corresponding Mandelstam constraints of\n(d+1) dimensional SU(2) lattice gauge theory in terms of harmonic oscillator\nprepotentials. This enables us to explicitly construct a complete orthonormal\nand manifestly gauge invariant basis in the physical Hilbert space. Further, we\nshow that this gauge invariant description represents networks of unoriented\nloops carrying certain non-negative abelian fluxes created by the harmonic\noscillator prepotentials. The loop network is characterized by $3(d-1)$ gauge\ninvariant integers at every lattice site which is the number of physical\ndegrees of freedom. Time evolution involves local fluctuations of these loops.\nThe loop Hamiltonian is derived. The generalization to SU(N) gauge group is\ndiscussed.",
        "positive": "B-parameters for DeltaS = 2 Supersymmetric Operators: We present a calculation of the matrix elements of the most general set of\nDeltaS=2 dimension-six four-fermion operators. The values of the matrix\nelements are given in terms of the corresponding B-parameters. Our results can\nbe used in many phenomenological applications, since the operators considered\nhere give important contributions to K^0--K^0bar mixing in several extensions\nof the Standard Model (supersymmetry, left-right symmetric models, multi-Higgs\nmodels etc.). The determination of the matrix elements improves the accuracy of\nthe phenomenological analyses intended to put bounds on basic parameters of the\ndifferent models, as for example the pattern of the sfermion mass matrices. The\ncalculation has been performed on the lattice, using the tree-level improved\nClover action at two different values of the strong coupling constant\n(beta=6/g_0^2(a)=6.0 and 6.2, corresponding to a^-1= 2.1 and 2.7 GeV\nrespectively), in the quenched approximation. The renormalization constants and\nmixing coefficients of the lattice operators have been obtained\nnon-perturbatively."
    },
    {
        "anchor": "Strategy to find the two $\u039b(1405)$ states from lattice QCD\n  simulations: Theoretical studies within the chiral unitary approach, and recent\nexperiments, have provided evidence of the existence of two isoscalar states in\nthe region of the $\\Lambda(1405)$. In this paper we use the same chiral\napproach to generate energy levels in a finite box. In a second step, assuming\nthat these energies correspond to lattice QCD results, we devise the best\nstrategy of analysis to obtain the two states in the infinite volume case, with\nsufficient precision to distinguish them. We find out that using energy levels\nobtained with asymmetric boxes and/or with a moving frame, with reasonable\nerrors in the energies, one has a successful scheme to get the two\n$\\Lambda(1405)$ poles.",
        "positive": "Evidence for a BKT transition and a pseudogap phase in three-dimensional\n  Gross-Neveu model at nonzero temperature: We present results from Monte Carlo simulations of the three-dimensional\nGross-Neveu model with a U(1) chiral symmetry at nonzero temperature. We\nprovide evidence that the model undergoes a Berezinskii-Kosterlitz-Thouless\ntransition in accordance with the dimensional reduction scenario. We also\nidentify a regime in the high temperature phase in which the fermions acquire\nnonzero dynamical mass, analogous to the pseudogap behaviour observed in\ncuprate superconductors."
    },
    {
        "anchor": "QCD with light Wilson quarks on fine lattices (I): first experiences and\n  physics results: Recent conceptual, algorithmic and technical advances allow numerical\nsimulations of lattice QCD with Wilson quarks to be performed at significantly\nsmaller quark masses than was possible before. Here we report on simulations of\ntwo-flavour QCD at sea-quark masses from slightly above to approximately 1/4 of\nthe strange-quark mass, on lattices with up to 64x32^3 points and spacings from\n0.05 to 0.08 fm. Physical sea-quark effects are clearly seen on these lattices,\nwhile the lattice effects appear to be quite small, even without O(a)\nimprovement. A striking result is that the dependence of the pion mass on the\nsea-quark mass is accurately described by leading-order chiral perturbation\ntheory up to meson masses of about 500 MeV.",
        "positive": "The First Order Signal in Pure U(1) Gauge Theory May be Fake: We study the deconfinement phase transition of compact $U(1)$ pure lattice\ngauge theory with the Wilson action on {\\em closed topology} lattices. In\ncontrast to studies of compact QED on {\\em hypercubic lattices with periodic\nboundary conditions}, we find no metastability signal at the phase transition\non the lattices with the topology of a sphere. Thus the determination of the\norder of this phase transition has to be reconsidered. We argue that different\nproperties of closed monopole loops on these topological inequivalent lattices\nmight be responsible for the effect."
    },
    {
        "anchor": "Effective spin models for the confinement phase transition: Spatial correlations - bubbles, domain walls, etc. - can best be studied by\nconcentrating on the degrees of freedom most relevant to the problem. For the\nfinite temperature confinement transition, I integrate out all gauge degrees of\nfreedom, leaving only spins - Ising or Potts - related to the Wilson line. I\npresent problems that arise in the course of this transformation and some\nresults for the effective spin action.",
        "positive": "Gradient-flowed thermal correlators: how much flow is too much?: Gradient flow has been proposed in the lattice community as a tool to reduce\nthe sensitivity of operator correlation functions to noisy UV fluctuations. We\ntest perturbatively under what conditions doing so may contaminate the results.\nTo do so, we compute gradient-flowed electric field two-point correlators and\nstress tensor one- and two-point correlators at finite temperature in QCD.\nGradient flow has almost no influence on the value of correlators until a\n(temperature- and separation-dependent) level of flow is reached, after which\nthe correlator is rapidly compromised. We provide a prescription for how much\nflow is \"safe.\""
    },
    {
        "anchor": "On the Continuum Limit of Topological Charge Density Distribution: The bulk distribution of the topological charge density, constructed via HP^1\nsigma-model embedding method, is investigated. We argue that the specific\npattern of leading power corrections to gluon condensate hints on a particular\nUV divergent structure of HP^1 sigma-model fields, which in turn implies the\nlinear divergence of the corresponding topological density in the continuum\nlimit. We show that under testable assumptions the topological charge is to be\ndistributed within three-dimensional sign-coherent domains and conversely, the\ndimensionality of sign-coherent regions dictates the leading divergence of the\ntopological density. Confronting the proposed scenario with lattice data we\npresent evidence for indeed peculiar divergence of the embedded fields. Then\nthe UV behavior of the topological density is studied directly and is found to\nagree with our proposition. Finally, we introduce parameter-free method to\ninvestigate the dimensionality of relevant topological fluctuations and show\nthat indeed topological charge sign-coherent regions are likely to be\nthree-dimensional.",
        "positive": "A Python program for the implementation of the \u0393-method for Monte\n  Carlo simulations: We present a modular analysis program written in Python devoted to the\nestimation of autocorrelation times for Monte Carlo simulations by means of the\n$\\Gamma$-method algorithm. We give a brief review of this method and describe\nthe main features of the program. The latter is characterized by a\nuser-friendly interface and an open source environment which, along with its\nmodularity, make it a versatile tool. Finally we present a simple application\nas an operational test for the program."
    },
    {
        "anchor": "Projective Cooling for the transverse Ising model: We demonstrate the feasibility of ground state preparation for the transverse\nIsing model using projective cooling, and show that the algorithm can\neffectively construct the ground state in the disordered (paramagnetic) phase.\nOn the other hand, significant temperature effects are encountered in the\nordered (ferromagnetic) phase requiring larger lattices to accurately simulate.",
        "positive": "Spectroscopy From The Lattice: The Scalar Glueball: Lattice calculations allow us to probe the low-lying, non-perturbative\nspectrum of QCD using first principles numerical methods. Here we present the\nlow-lying spectrum in the scalar sector with vacuum quantum numbers including,\nin fully dynamical QCD for the first time, the mixing between glueball, q-qbar,\nand meson-meson operators."
    },
    {
        "anchor": "The effective U(1)-Higgs theory at strong coupling on optical lattices?: We discuss the U(1)-Higgs model in two dimensions in the strongly coupled\nregime. If we neglect the plaquette interactions, we generate an effective\ntheory where link variables are integrated out, producing 4-field operators.\nPlaquette interactions can be restored order by order as in recent calculations\nwith staggered fermions. In the case of a SU(2) gauge theory with fermions,\nthis strong coupling expansion can be related to the strong coupling expansion\nof Fermi-Hubbard models possibly implementable on optical lattice. We would\nlike to provide a similar construction relating the U(1)-Higgs model to some\nBose-Hubbard model. As a first step in this direction, we discuss a recent\nproposal to implement the O(2) model on optical lattices using a 87Rb and 41K\nBose-Bose mixture of cold atoms.",
        "positive": "Fermi-Einstein condensation in dense QCD-like theories: While pure Yang-Mills theory feature the centre symmetry, this symmetry is\nexplicitly broken by the presence of dynamical matter. We study the impact of\nthe centre symmetry in such QCD-like theories. In the analytically solvable\nSchwinger model, centre transitions take place even under extreme conditions,\ntemperature and/or density, and we show that they are key to the solution of\nthe Silver-Blaze problem. We then develop an effective SU(3) quark model which\nconfines quarks by virtue of centre sector transitions. The phase diagram by\nconfinement is obtained as a function of the temperature and the chemical\npotential. We show that at low temperatures and intermediate values for the\nchemical potential the centre dressed quarks undergo condensation due to Bose\nlike statistics. This is the Fermi Einstein condensation. To corroborate the\nexistence of centre sector transitions in gauge theories with matter, we study\n(at vanishing chemical potential) the interface tension in the\nthree-dimensional Z2 gauge theory with Ising matter, the distribution of the\nPolyakov line in the four-dimensional SU(2)-Higgs model and devise a new type\nof order parameter which is designed to detect centre sector transitions. Our\nanalytical and numerical findings lead us to conjecture a new state of cold,\nbut dense matter in the hadronic phase for which Fermi Einstein condensation is\nrealised."
    },
    {
        "anchor": "Four Gluon Vertex from Lattice QCD: A lattice QCD calculation for the four gluon one-particle irreducible Green\nfunction in the Landau gauge is discussed. Results for some of the associated\nform factors are reported for kinematical configurations with a single momentum\nscale. Our results show that the computation of this Green function requires\nlarge statistical ensembles with 10K or larger number of gauge configurations.\nThe simulations considered herein have a clear Monte Carlo signal for momenta\nup to $\\sim 1$ GeV. The form factors show an hierarchy, with the form factor\nassociated with the tree level Feynman rule being dominant and essentially\nconstant for the range of momenta accessed. The remaining form factors seem to\nincrease as the momentum decreases, suggesting that a possible $\\log$\ndivergence may occur. The computed form factors are, at least, in qualitative\nagreement with the results obtained with continuum approaches to this vertex,\nwhen available.",
        "positive": "Direct calculation of hadronic light-by-light scattering: We report calculations of hadronic light-by-light scattering amplitudes via\nlattice QCD evaluation of Euclidean four-point functions of vector currents.\nThese initial results include only the fully quark-connected contribution.\nParticular attention is given to the case of forward scattering, which can be\nrelated via dispersion relations to the $\\gamma^* \\gamma^* \\to$ hadrons cross\nsection, and thus allows lattice data to be compared with phenomenology. We\nalso present a strategy for computing the hadronic light-by-light contribution\nto the muon anomalous magnetic moment."
    },
    {
        "anchor": "M_pi^2 versus m_q: comparing CP-PACS and UKQCD data to Chiral\n  Perturbation Theory: I present a selection of CP-PACS and UKQCD data for the pseudo-Goldstone\nmasses in $N_f=2$ QCD with doubly degenerate quarks. At least the more chiral\npoints should be consistent with Chiral Perturbation Theory for the latter to\nbe useful in an extrapolation to physical masses. I find consistency with the\nchiral prediction but no striking evidence for chiral logs. Nonetheless, the\nconsistency guarantees that the original estimate, by Gasser and Leutwyler, of\nthe $N_f=2$ QCD low-energy scale $\\Lambda_3$ was not entirely wrong.",
        "positive": "QCD bulk thermodynamics and conserved charge fluctuations with HISQ\n  fermions: After briefly reviewing recent progress by the HotQCD collaboration in\nstudying the 2+1 flavor QCD equation of state, we will focus on results on\nfluctuations of conserved charges by the BNL-Bielefeld and HotQCD\ncollaborations. Higher order cumulants of the net-charge distributions are\nincreasingly dominated by a universal scaling behavior, which arises due to a\ncritical point of QCD in the chiral limit. Considering cumulants up to the\n6^{th} order, we observe that they generically behave as expected from\nuniversal scaling laws, which is quite different from cumulants calculated\nwithin the hadron resonance gas model. Taking ratios of these cumulants, we\nobtain volume independent results that can be compared to the experimental\nmeasurements. We will argue that the freeze-out chemical potentials and the\nfreeze-out temperature, usually obtained by a HRG model fit to the measured\nhadronic yields, can also be obtained in a model independent way from ab-initio\nlattice QCD calculations by utilizing observables related to conserved charge\nfluctuations. Further, we will show that the freeze-out strangeness and\nelectric charge chemical potentials can be fixed by imposing strangeness\nneutrality and isospin asymmetry constraints in the lattice QCD calculations,\nin order to accommodate conditions met in heavy ion collisions. All results\nhave been obtained with the highly improved staggered quark action (HISQ) and\nalmost physical quark masses on lattices with temporal extent of\nN_\\tau=6,8,10,12."
    },
    {
        "anchor": "Glueballs from the Lattice: Recent numerical calculations of the glueball spectrum in QCD, in SU($N$)\nYang-Mills theory in the large-$N$ limit and in candidate theories of strongly\ninteracting dynamics beyond the standard model (in which the lowest-lying\nscalar plays the role of the Higgs boson) are reviewed and their implications\nfor our theoretical understanding of glueballs in QCD-like theories and in\nstrongly coupled gauge theories with a (near-)conformal dynamics are discussed.",
        "positive": "Critical statistics at the mobility edge of QCD Dirac spectra: We examine statistical fluctuation of eigenvalues from the near-edge bulk of\nQCD Dirac spectra above the critical temperature. For completeness we start by\nreviewing on the spectral property of Anderson tight-binding Hamiltonians as\ndescribed by nonlinear sigma models and random matrices, and on the\nscale-invariant intermediate spectral statistics at the mobility edge. By\nfitting the level spacing distributions, deformed random matrix ensembles which\nmodel multifractality of the wave functions typical of the Anderson\nlocalization transition, are shown to provide an excellent effective\ndescription for such a critical statistics. Next we carry over the above\nstrategy for the Anderson Hamiltonians to the Dirac spectra. For the staggered\nDirac operators of QCD with 2+1 flavors of dynamical quarks at the physical\npoint and of SU(2) quenched gauge theory, we identify the precise location of\nthe mobility edge as the scale-invariant fixed point of the level spacing\ndistribution. The eigenvalues around the mobility edge are shown to obey\ncritical statistics described by the aforementioned deformed random matrix\nensembles of unitary and symplectic classes. The best-fitting deformation\nparameter for QCD at the physical point turns out to be consistent with the\nAnderson Hamiltonian in the unitary class. Finally, we propose a method of\nlocating the mobility edge at the origin of QCD Dirac spectrum around the\ncritical temperature, by the use of individual eigenvalue distributions of\ndeformed chiral random matrices."
    },
    {
        "anchor": "Practical Implementation of Lattice QCD Simulation on SIMD Machines with\n  Intel AVX-512: We investigate implementation of lattice Quantum Chromodynamics (QCD) code on\nthe Intel AVX-512 architecture. The most time consuming part of the numerical\nsimulations of lattice QCD is a solver of linear equation for a large sparse\nmatrix that represents the strong interaction among quarks. To establish widely\napplicable prescriptions, we examine rather general methods for the SIMD\narchitecture of AVX-512, such as using intrinsics and manual prefetching, for\nthe matrix multiplication. Based on experience on the Oakforest-PACS system, a\nlarge scale cluster composed of Intel Xeon Phi Knights Landing, we discuss the\nperformance tuning exploiting AVX-512 and code design on the SIMD architecture\nand massively parallel machines. We observe that the same code runs efficiently\non an Intel Xeon Skylake-SP machine.",
        "positive": "Percolation and Critical Behaviour in SU(2) Gauge Theory: The paramagnetic-ferromagnetic transition in the Ising model can be described\nas percolation of suitably defined clusters. We have tried to extend such\npicture to the confinement-deconfinement transition of SU(2) pure gauge theory,\nwhich is in the same universality class of the Ising model. The cluster\ndefinition is derived by approximating SU(2) by means of Ising-like effective\ntheories. The geometrical transition of such clusters turns out to describe\nsuccessfully the thermal counterpart for two different lattice regularizations\nof (3+1)-d SU(2)."
    },
    {
        "anchor": "Update on the sea contributions to hadron polarizabilities via\n  reweighting: We have made significant progress on extending lattice QCD calculation of the\npolarizability of the neutron and other hadrons to include the effects of\ncharged dynamical quarks. This is done by perturbatively reweighting the\ncharges of the sea quarks to couple them to the background field. The dominant\nchallenge in such a calculation is stochastic estimation of the weight factors,\nand we discuss the difficulties in this estimation. Here we use an extremely\naggressive dilution scheme with N = 124,416 sources per configuration to reduce\nthe stochastic noise to a manageable level. We find that \\alpha_E = 2.70(55) *\n10^-4 fm^3 for the neutron on one ensemble. We show that low-mode substitution\ncan be used in tandem with dilution to construct an even better estimator, and\nintroduce the offdiagonal matrix element mapping technique for predicting\nestimator quality.",
        "positive": "Quantum Fluctuations versus Topology - a Study in U(1)_2 Lattice Gauge\n  Theory: Using the geometric definition of the topological charge we decompose the\npath integral of 2-dimensional U(1) lattice gauge theory into topological\nsectors. In a Monte Carlo simulation we compute the average value of the action\nas well as the distribution of its values for each sector separately. These\nnumbers are compared with analytic lower bounds of the action which are\nrelevant for classical configurations carrying topological charge. We find that\nquantum fluctuations entirely dominate the path integral. Our results for the\nprobability distribution of the Monte Carlo generated configurations among the\ntopological sectors can be understood by a semi-phenomenological argument."
    },
    {
        "anchor": "Efficient Basis Formulation for (1+1)-Dimensional SU(2) Lattice Gauge\n  Theory: Spectral calculations with matrix product states: We propose an explicit formulation of the physical subspace for a\n(1+1)-dimensional SU(2) lattice gauge theory, where the gauge degrees of\nfreedom are integrated out. Our formulation is completely general, and might be\npotentially suited for the design of future quantum simulators. Additionally,\nit allows for addressing the theory numerically with matrix product states. We\napply this technique to explore the spectral properties of the model and the\neffect of truncating the gauge degrees of freedom to a small finite dimension.\nIn particular, we determine the scaling exponents for the vector mass.\nFurthermore, we also compute the entanglement entropy in the ground state and\nstudy its scaling towards the continuum limit.",
        "positive": "Mesonic decay constant and mass ratios and the conformal window: Two particular ratios related to mesons are proposed for the study of the\nconformal window in $SU(3)$ gauge theory and fundamental fermions. Lattice and\nother studies indicate that the lower end, $N_f^*$, is at around 7 - 13 flavors\nwhich is a wide range without a clear consensus. Here we propose the decay\nconstant to mass ratios of mesons, $f_{PS,V} / m_V$, as a proxy since below the\nconformal window lattice studies have shown that they are largely\n$N_f$-independent while at the upper end of the conformal window they are\nvanishing. The drop from the non-zero constant value to zero at $N_f = 16.5$\nmight be indicative of $N_f^*$. We compute $f_V / m_V$ to N$^3$LO and $f_{PS} /\nm_V$ to NNLO order in (p)NRQCD. The results are unambiguously reliable just\nbelow $N_f = 16.5$, hence the results are expanded \\'a la Banks-Zaks in\n$\\varepsilon = 16.5 - N_f$. The convergence properties of the series and\nmatching with the non-perturbative infinite volume, continuum and chiral\nextrapolated lattice results at $N_f = 10$ suggest that the perturbative\nresults might be reliable down to $N_f = 12$. A sudden drop is observed at $N_f\n= 12$ and $N_f = 13$ in $f_V / m_V$ and $f_{PS} / m_V$, respectively."
    },
    {
        "anchor": "Fractal Structure in Two-Dimensional Quantum Regge Calculus: We study the fractal structure of the surface in two-dimensional quantum\nRegge calculus by performing Monte Carlo simulation with up to 200,000\ntriangles. The result can be compared with the universal scaling function\nobtained analytically in the continuum limit of dynamical triangulation, which\nprovides us with a definite criterion whether Regge calculus serves as a proper\nregularization of quantum gravity. When the scale-invariant measure is taken as\nthe measure of the link-length integration, we observe the correct scaling\nbehavior in the data for the type of loop attached to a baby universe. The data\nseem to converge to the universal scaling function as the number of triangles\nis increased. The data for the type of loop attached to the mother universe, on\nthe other hand, shows no scaling behavior up to the present size.",
        "positive": "String Breaking in SU(2) Yang Mills Theory with Adjoint Sources: We compute the static potential in three-dimensional SU(2) Yang Mills Theory\nwith adjoint sources using numerical simulations. By employing a variational\napproach involving string and gluelump operators, we obtain clear evidence for\nstring breaking in the adjoint potential. The breaking scale r_b is computed\nand extrapolated to the continuum limit. The result in units of the scalar\nglueball mass is r_b*m_G = 10.3 +/- 1.5. We also resolve the structure of\nhigher excitations of the flux-tube and gluelumps. Furthermore we discuss the\nimplications of our findings for the case of the four-dimensional theory."
    },
    {
        "anchor": "Meson Correlators in Finite Temperature Lattice QCD: We analyze temporal and spatial meson correlators in quenched lattice QCD at\nT>0. Below T_c we observe little change in the meson properties as compared\nwith T=0. Above T_c we observe new features: chiral symmetry restoration and\nsignals of plasma formation, but also indication of persisting mesonic\n(metastable) states and different temporal and spatial masses in the mesonic\nchannels. This suggests a complex picture of QGP in the region 1 - 1.5 T_c.",
        "positive": "The clash of positivities in topological density correlators: We discuss the apparent conflict between reflection positivity and positivity\nof the topological susceptibility in two-dimensional nonlinear sigma models and\nin four-dimensional gauge theories. We pay special attention to the fact that\nthis apparent conflict is already present on the lattice; its resolution puts\nsome nontrivial restrictions on the short-distance behavior of the lattice\ncorrelator. It is found that these restrictions can be satisfied both in the\ncase of asymptotic freedom and the dissident scenario of a critical point at\nfinite coupling."
    },
    {
        "anchor": "Speeding up Lattice QCD simulations with clover-improved Wilson Fermions: We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of\nsystems with dynamical fermions to two flavour QCD with clover-improvement. The\nbasic idea of our proposal is to split the fermion matrix into two factors with\na reduced condition number each. In the effective action, for both factors a\npseudo-fermion field is introduced. For our smallest quark masses we see a\nspeed-up of more than a factor of two compared with the standard algorithm.",
        "positive": "Correlation and localization properties of topological charge density\n  and the pseudoscalar glueball mass in SU(3) lattice Yang-Mills theory: Towards the goal of extracting the continuum properties, we have studied the\nTopological Charge Density Correlator (TCDC) and the Inverse Participation\nRatio (IPR) for the topological charge density ($q(x)$) in SU(3) Lattice\nYang-Mills theory for relatively small lattice spacings including some smaller\nthan those explored before. With the help of recently proposed open boundary\ncondition, it is possible to compute observables at a smaller lattice spacing\nsince {\\em trapping problem} is absent. On the other hand, the reference energy\nscale provided by Wilson flow allows us to study their scaling behavior in\ncontrast to previously proposed smearing techniques. The behavior of TCDC for\ndifferent lattice spacings at a fixed HYP smearing level shows apparent scaling\nviolations. In contrast, at a particular Wilson flow time $t$ for all the\nlattice spacings investigated (except the largest one), the TCDC data show\nuniversal behavior within our statistical uncertainties. The continuum\nproperties of TCDC are studied by investigating the small flow time behavior.\nWe have also extracted the pseudoscalar glueball mass from TCDC, which appears\nto be insensitive to the lattice spacings (0.0345 fm $\\leq a\\leq$ 0.0667 fm)\nand agrees with the value extracted using anisotropic lattices, within\nstatistical errors. Further, we have studied the localization property of\n$q(x)$ through IPR whose continuum behavior can be probed through the small\nvalues of Wilson flow time and observed the decrease of IPR with decreasing\nWilson flow time. A detailed study of $q(x)$ under Wilson flow time revealed\nthat as Wilson flow time decreases, the proximity of the regions of positive\nand negative charge densities of large magnitudes increases, and the charge\ndensity appears to be more delocalized resulting in the observed behavior of\nIPR."
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory and the Gradient Flow: We study the Yang-Mills gradient flow using numerical stochastic perturbation\ntheory. As an application of the method we consider the recently proposed\ngradient flow coupling in the Schr\\\"odinger functional for the pure SU(3) gauge\ntheory.",
        "positive": "Abelian dominance in local unitary gauges and without gauge-fixing in\n  pure SU(2) QCD: We perform lattice Monte-Carlo simulations of pure SU(2) QCD using the\nmulti-level method. We find Abelian dominance in local unitary gauges such as\nthose diagonalizing a plaquette. A static potential described by Abelian link\nfields alone gives us the same string tension as that of a non-Abelian\npotential. Abelian dominance of the string tension and Abelian flux tube\nprofiles are observed also without gauge-fixing, i.e., without any Abelian\nprojection. On the basis of these results, we propose a simple\ngauge-independent Abelian confinement scenario without any Abelian projection.\nAll color components of the non-Abelian field strength become Abelian dominant\nin the infrared region. The Abelian dual Meissner effect works in any color\ndirection. Abelian neutral states in any color directions which are just\nnon-Abelian color-singlet can exist as a physical state. In this way, the\nnon-Abelian color confinement could be understood in the framework of the\nAbelian dual Meissner effect."
    },
    {
        "anchor": "Quark-anti-quark potentials from Nambu-Bethe-Salpeter amplitudes on\n  lattice: Quark--anti-quark (anti-q-q) potentials with finite quark masses are studied\nfrom the anti-q-q Nambu-Bethe-Salpeter (NBS) wave functions in quenched lattice\nQCD. With the use of a method which has been recently developed in the\nderivation of nuclear forces from lattice QCD, we derive the anti-q-q\npotentials from the NBS wave functions. We calculate the anti-q-q NBS wave\nfunctions in pseudo-scalar and vector channels for several quark masses. The\nderived potentials at each quark mass in both channels show linear plus Coulomb\nform. We also discuss the quark-mass and channel dependence of the anti-q-q\npotentials.",
        "positive": "U(1) Problem at Finite Temperature: We model the effects of a large number of zero and near-zero modes in the QCD\npartition function by using sparse chiral matrix models with an emphasis on the\nquenched topological susceptibility in the choice of the measure. At finite\ntemperature, the zero modes are not affected by temperature but are allowed to\npair into topologically neutral near-zero modes which are gapped at high\ntemperature. In equilibrium, chiral and U(1) symmetry are simultaneously\nrestored for total pairing, evading mean-field arguments. We analyze a number\nof susceptibilities versus the light quark masses. At the transition point the\ntopological susceptibility vanishes, and the dependence on the vacuum angle\n$\\theta$ drops out. Our results are briefly contrasted with recent lattice\nsimulations."
    },
    {
        "anchor": "Gribov Copies and Other Gauge Fixing Beasties on the Lattice: Write-up for Lattice'92, held in Amsterdam. preprint LTH 291.\n  Comes with 6 PostScript figures and 1 sty-file. We study the nature of gauge\nfixing ambiguities in two dimensional gauge theories. We find that these\nambiguities can be related to the asociated spin model. They can be eliminated\nby means of a (multigrid) annealing algorithm.",
        "positive": "Study of theta-Vacua in the 2-d O(3) Model: We investigate the continuum limit of the step scaling function in the 2-d\nO(3) model with different theta-vacua. Since we find a different continuum\nvalue of the step scaling function for each value of theta, we can conclude\nthat theta indeed is a relevant parameter of the theory and does not get\nrenormalized non-perturbatively. Furthermore, we confirm the result of the\nconjectured exact S-matrix theory, which predicts the continuum value at theta\n= pi. To obtain high precision data, we use a modified Hasenbusch improved\nestimator and an action with an optimized constraint, which has very small\ncut-off effects. The optimized constraint action combines the standard action\nof the 2-d O(3) model with a topological action. The topological action\nconstrains the angle between neighboring spins and is therefore invariant\nagainst small deformations of the field."
    },
    {
        "anchor": "Effective Mass Generation of Off-diagonal Gluons and Abelian Dominance\n  in the Maximally Abelian Gauge in QCD: We study the properties of gluons in QCD in the maximally abelian (MA) gauge.\nIn the MA gauge, the off-diagonal gluon behaves as the massive vector boson\nwith the mass $\\Meff \\simeq 1.2 {\\rm GeV}$, and therefore the off-diagonal\ngluon cannot carry the long-range interaction for $r \\gg \\Meff^{-1} \\simeq 0.2$\nfm. The essence of the infrared abelian dominance in the MA gauge is physically\nexplained with the generation of the off-diagonal gluon mass $\\Meff \\simeq 1.2\n{\\rm GeV}$ induced by the MA gauge fixing, and the off-diagonal gluon mass\ngeneration would predict general infrared abelian dominance in QCD in the MA\ngauge. We report also the off-diagonal gluon propagator at finite temperature.",
        "positive": "A lattice QCD determination of the neutron electric dipole moment at the\n  physical point: Results are presented on the neutron electric dipole moment using an ensemble\nof $N_f=2+1+1$ twisted mass clover-improved fermions with lattice spacing of\n$a\\simeq 0.08$ fm and physical pion mass ($m_\\pi\\simeq 139$ MeV). The approach\nfollowed in this work is to compute the $CP$-odd electromagnetic form factor\n$F_3(Q^2\\rightarrow0)$ at zero momentum transfer by expanding the action to\nleading order in $\\theta$. This gives rise to correlation functions that\ninvolve the topological charge, for which we employ a fermionic definition by\nmeans of spectral projectors. We include a comparison between the results using\nthe fermionic and the gluonic definition, where for the latter we employ the\ngradient flow. We show that using spectral projectors leads to half the\nstatistical uncertainty on the evaluation of $F_3(0)$. Using the fermionic\ndefinition, we find a value of $\\lvert d_N\\rvert = 0.0009(24)\\,\\theta\\,\n\\rm{e}\\cdot\\rm{fm}$."
    },
    {
        "anchor": "Tackling the sign problem with a moment expansion and application to\n  Heavy dense QCD: Heavy-Dense QCD (HDQCD) is a popular theory to investigate the sign problem\nin quantum field theory. Besides its physical applications, HDQCD is relatively\neasy to implement numerically: the fermionic degrees of freedom are integrated\nout, and the fermion determinant factorises into local ones. The theory has a\nsign problem, the severeness of which depends on the value of the chemical\npotential, which makes this theory ideal to test the reach of new algorithms.\nWe use the LLR approach to obtain the probability distribution of the phase of\nthe fermion determinant. Our goal is the calculation of the phase factor\nexpectation value, which appears as Fourier transform of this probability\ndistribution. We here propose a new and systematic moment expansion for this\nphase factor. We compare the answer from the moment expansion order by order\nwith the exact answer. We find that this expansion converge quickly and works\nvery well in the strong sign problem region.",
        "positive": "Light-Neutrino Exchange and Long-Distance Contributions to $0\\nu2\u03b2$\n  Decays: An Exploratory Study on $\u03c0\u03c0\\to ee$: We present an exploratory lattice QCD calculation of the neutrinoless double\nbeta decay $\\pi\\pi\\to ee$. Under the mechanism of light-neutrino exchange, the\ndecay amplitude involves significant long-distance contributions. The\ncalculation reported here, with pion masses $m_\\pi=420$ and 140 MeV,\ndemonstrates that the decay amplitude can be computed from first principles\nusing lattice methods. At unphysical and physical pion masses, we obtain that\namplitudes are $24\\%$ and $9\\%$ smaller than the predication from leading order\nchiral perturbation theory. Our findings provide the lattice QCD inputs and\nconstraints for effective field theory. A follow-on calculation with fully\ncontrolled systematic errors will be possible with adequate computational\nresources."
    },
    {
        "anchor": "Massive Domain Wall Fermions on Four-dimensional Anisotropic Lattices: We formulate the massive domain wall fermions on anisotropic lattices.\n  For the massive domain wall fermion, we find that the dispersion relation\nassumes the usual form in the low momentum region when the bare parameters are\nproperly tuned. The quark self-energy and the quark field renormalization\nconstants are calculated to one-loop in bare lattice perturbation theory. For\nlight domain wall fermions, we verified that the chiral mode is stable against\nquantum fluctuations on anisotropic lattices. This calculation serves as a\nguidance for the tuning of the parameters in the quark action in future\nnumerical simulations.",
        "positive": "Complex Langevin: Correctness criteria, boundary terms and spectrum: The Complex Langevin (CL) method to simulate `complex probabilities', ideally\nproduces expectation values for the observables that converge to a limit equal\nto the expectation values obtained with the original complex `probability'\nmeasure. The situation may be spoiled in two ways: failure to converge and\nconvergence to the wrong limit. It was found long ago that `wrong convergence'\nis caused by boundary terms; non-convergence may arise from bad spectral\nproperties of the various evolution operators related to the CL process. Here\nwe propose a class of criteria which allow to rule out boundary terms and at\nthe same time bad spectrum. Ruling out boundary terms in the equilibrium\ndistribution arising from a CL simulation implies that the so-called\nconvergence conditions are fulfilled. This in turn has been shown to guarantee\nthat the expectation values of holomorphic observables are given by complex\nlinear combinations of $\\exp(-S)$ over various integration cycles. If the\nspectrum is pathological, however, the CL simulation in general does not\nreproduce the integral over the desired real cycle."
    },
    {
        "anchor": "The Use of Schoonschip and Form in Perturbative Lattice Calculations: Using the formal languages Schoonschip and Form, we have developed general\ncodes that are able to carry out all the algebraic manipulations needed to\nperform analytic lattice calculations, starting from the elementary building\nblocks (propagators and vertices) of each Feynman diagram. The main difficulty\nresides in the fact that, although there are many built in instructions to deal\nwith Dirac gamma-matrices, Schoonschip and Form have been conceived having in\nmind a continuum theory, which is invariant with respect to the Lorentz group.\nOn the lattice, on the contrary, a field theory is only invariant with respect\nto the hypercubic group, contained in the (euclidean) Lorentz group and not\nevery pair of equal indices should be summed over. Being impossible to directly\nuse the `gammatrics' of Schoonschip and Form as they are, special routines have\nbeen developed to correctly treat gamma matrices on the lattice, while using as\nmuch as possible of the built in Schoonschip and Form commands. We have used\nour codes to compute, in 1-loop perturbation theory in lattice QCD, the\nrenormalization constants and mixing coefficients of the operators that enter\nin the determination of the first two moments of deep inelastic scattering\nstructure functions.",
        "positive": "Infinite volume and continuum limits for gluon propagator in 3d SU(2)\n  lattice gauge theory: We study the Landau gauge gluon propagator D(p) in the 3d SU(2) lattice gauge\ntheory. We show that in the infinite-volume limit the expectation values over\nthe Gribov region \\Omega, are different (in the infrared) from that calculated\nin the fundamental modular region \\Gamma. Also we show that this conclusion\ndoes not change when spacing $a$ tends to zero."
    },
    {
        "anchor": "Multigrid for propagators of staggered fermions in four-dimensional\n  $SU(2)$ gauge fields: Multigrid (MG) methods for the computation of propagators of staggered\nfermions in non-Abelian gauge fields are discussed. MG could work in principle\nin arbitrarily disordered systems. The practical variational MG methods tested\nso far with a ``Laplacian choice'' for the restriction operator are not\ncompetitive with the conjugate gradient algorithm on lattices up to $18^4$.\nNumerical results are presented for propagators in $SU(2)$ gauge fields.",
        "positive": "Larger physical volume with a noncompact lattice regularization of SU(N)\n  theories: Recently it has been found that in a noncompact formulation of the SU(2)\ngauge theory on a lattice the physical volume is larger than in the Wilson\ntheory with the same number of sites. In its original formulation such\nnoncompact regularization is directly applicable to U(N) theories for any N and\nto SU(N) theories for N=2 only. In this work we extend it to SU(N) for any N\nand investigate some of its properties."
    },
    {
        "anchor": "Critical Behaviour in the Single Flavor Planar Thirring Model: We report results of simulations of the $2+1d$ Thirring model with $N$\nfermion flavors, defined on a lattice using domain wall fermions. This approach\nis devised to respect as far as possible the underlying U($2N$) symmetry of the\ncontinuum model, expected to be recovered in the limit wall separation\n$L_s\\to\\infty$. For $N=1$ there is a symmetry-breaking phase transition\nassociated with bilinear condensation at strong fermion self-interaction, which\nis a plausible location for a quantum critical point. Fits to a renormalisation\ngroup-inspired equation of state yield critical exponents distinct from those\nobtained using a version of the model defined using staggered fermions.",
        "positive": "Predicting positive parity $B_{s}$ mesons from lattice QCD: We determine the spectrum of $B_s$ 1P states using lattice QCD. For the\n$B_{s1}(5830)$ and $B_{s2}^*(5840)$ mesons, the results are in good agreement\nwith the experimental values. Two further mesons are expected in the quantum\nchannels $J^P=0^+$ and $1^+$ near the $BK$ and $B^{*}K$ thresholds. A\ncombination of quark-antiquark and $B^{(*)}$ meson-Kaon interpolating fields\nare used to determine the mass of two QCD bound states below the $B^{(*)}K$\nthreshold, with the assumption that mixing with $B_s^{(*)}\\eta$ and\nisospin-violating decays to $B_s^{(*)}\\pi$ are negligible. We predict a\n$J^P=0^+$ bound state $B_{s0}$ with mass $m_{B_{s0}}=5.711(13)(19)$ GeV. With\nfurther assumptions motivated theoretically by the heavy quark limit, a bound\nstate with $m_{B_{s1}}= 5.750(17)(19)$ GeV is predicted in the $J^P=1^+$\nchannel. The results from our first principles calculation are compared to\nprevious model-based estimates."
    },
    {
        "anchor": "Decomposition of the static potential in SU(3) gluodynamics: After fixing the Maximal Abelian gauge in SU(3) lattice gluodynamics we\ndecompose the nonabelian gauge field into the Abelian field created by Abelian\nmonopoles and the modified nonabelian field with monopoles removed. We then\ncalculate respective static potentials in the fundamental representation and\nshow that the sum of these potentials approximates the nonabelian static\npotential with good precision at all distances considered. Comparison with\nother ways of decomposition is made.",
        "positive": "Perfect lattice action for asymptotically free theories: There exist lattice actions which give cut--off independent physical\npredictions even on coarse grained lattices. Rotation symmetry is restored, the\nspectrum becomes exact and, in addition, the classical equations have scale\ninvariant instanton solutions. This perfect action can be made short ranged. It\ncan be determined by combining analytical calculations with numerical\nsimulations on small lattices. We illustrate the method and the benefits on the\n$d=2$ non--linear $\\sigma$--model."
    },
    {
        "anchor": "Fractional Charge and Confinement of Quarks: In quantum chromodynamics with static quarks the confinement-deconfinement\nphase transition is connected to the spontaneous breaking of the global Z3\ncenter symmetry. This symmetry is lost when one considers dynamical quarks.\nOwing to the fractional electric charge of quarks, we recover a global Z6\ncenter symmetry when QCD is regarded as a part of the Standard Model. We\npresent results from QCD-like theories extended by electromagnetic interactions\nand show that the weak coupling limit of the QED part of the model results in a\ncenter-like symmetry with disorder in the vacuum. This can be seen explicitly\nin a character expansion of the fermion determinant. Further, we show that\ncorresponding center averages project the fermion determinant on N-ality zero\nand discuss whether the additional center symmetry can be used to eliminate the\nfermion sign problem in QCD with fundamental quarks.",
        "positive": "Heavy Hybrids from NRQCD: We present a quenched lattice calculation for the lowest lying $b \\bar b\ng$-hybrid states in the framework of NRQCD using the leading order Hamiltonian\nup to ${\\cal O}(mv^2)$. We demonstrate the existence of a nearly degenerate\nrotational band of states with an excitation energy approximately 1.6 GeV above\nthe $\\Upsilon$ ground state. This lies around the $B \\bar B_J^*$-threshold but\nwell above the $B \\bar B$-threshold. Therefore a heavy hybrid signal may well\nbe detected if the centre-of-mass energy in B-factories is raised a few hundred\nMeV to coincide with other resonances above the 4S state. Our prediction is\nconsistent with most phenomenological models and lattice calculations carried\nout in the static limit."
    },
    {
        "anchor": "Recent results on nucleon sigma terms in lattice QCD: It has proven a significant challenge to experiment and phenomenology to\nextract precise values of the nucleon sigma terms. This difficulty opens the\nwindow for lattice QCD simulations to lead the field in resolving this aspect\nof nucleon structure. Here we report on recent advances in the extraction of\nnucleon sigma terms in lattice QCD. In particular, the strangeness component is\nnow being resolved to a precision that far surpasses best phenomenological\nestimates.",
        "positive": "Canonical Demon Monte Carlo Renormalization Group: We describe a new method to compute renormalized coupling constants in a\nMonte Carlo renormalization group calculation. The method can be used for a\ngeneral class of models, e.g., lattice spin or gauge models. The basic idea is\nto simulate a joint system of block spins and canonical demons. In contrast to\nthe Microcanonical Renormalization Group invented by Creutz et al. our method\ndoes not suffer from systematical errors stemming from a simultaneous use of\ntwo different ensembles. We present numerical results for the $O(3)$ nonlinear\n$\\sigma$-model."
    },
    {
        "anchor": "Update on Heavy-Meson Spectrum Tests of the Oktay--Kronfeld Action: We present updated results of a numerical improvement test with heavy-meson\nspectrum for the Oktay--Kronfeld (OK) action. The OK action is an extension of\nthe Fermilab improvement program for massive Wilson fermions including all\ndimension-six and some dimension-seven bilinear terms. Improvement terms are\ntruncated by HQET power counting at $\\mathrm{O}(\\Lambda^3/m_Q^3)$ for\nheavy-light systems, and by NRQCD power counting at $\\mathrm{O}(v^6)$ for\nquarkonium. They suffice for tree-level matching to QCD to the given order in\nthe power-counting schemes. To assess the improvement, we generate new data\nwith the OK and Fermilab action that covers both charm and bottom quark mass\nregions on a MILC coarse $(a \\approx 0.12~\\text{fm})$ $2+1$ flavor,\nasqtad-staggered ensemble. We update the analyses of the inconsistency quantity\nand the hyperfine splittings for the rest and kinetic masses. With one\nexception, the results clearly show that the OK action significantly reduces\nheavy-quark discretization effects in the meson spectrum. The exception is the\nhyperfine splitting of the heavy-light system near the $B_s$ meson mass, where\nstatistics are too low to draw a firm conclusion, despite promising results.",
        "positive": "Magnetic structure of isospin-asymmetric QCD matter in neutron stars: We study QCD under the influence of background magnetic fields and isospin\nchemical potentials using lattice simulations. This setup exhibits a sign\nproblem which is circumvented using a Taylor-expansion in the magnetic field.\nThe ground state of the system in the pion condensation phase is found to\nexhibit a pronounced diamagnetic response. We elaborate on how this\ndiamagnetism may contribute to the pressure balance in the inner core of\nstrongly magnetized neutron stars. In addition we show that the onset of pion\ncondensation shifts to larger chemical potentials due to the enhancement of the\ncharged pion mass for growing magnetic fields. Finally, we sketch the magnetic\nstructure of the QCD phase diagram in the temperature-isospin chemical\npotential plane."
    },
    {
        "anchor": "Chiral extrapolations in 2+1 flavor domain wall fermion simulations: Simulations with 2+1 flavors of domain wall fermions provide us with the\nopportunity to compare the lattice data directly to the predictions of\ncontinuum chiral perturbation theory, up to corrections from the residual\nchiral symmetry breaking, $m_{res}$, and $O(a)$ lattice artefacts, which are\nrelatively small for domain wall fermions. We present preliminary results for\nthe pseudoscalar meson masses and decay constants from partially quenched\nsimulations and examine the next-to-leading order chiral extrapolations at\nsmall quark masses. The simulations were carried out on two lattice volumes :\n$16^3\\times 32$ and $24^3\\times 64$, with the lattice spacing fixed at about\n0.1 fm. The subtleties of the chiral fits are discussed. We also explore the\nroles of $m_{res}$ and $O(a)$ terms in the NLO chiral expansions and their\neffects on the chiral extrapolations for the pseudoscalar masses and decay\nconstants.",
        "positive": "Inverse Symmetry Breaking with 4d Lattice Simulations: According to resummed perturbation theory, certain scalar theories have a\nglobal symmetry, which is restored in the vacuum but is broken at high\ntemperatures. Recently, this phenomenon has been studied with 4d finite\ntemperature lattice simulations, and it has been suggested that the\nnon-perturbative dynamics thus incorporated would hinder the transition. We\nhave carried out another lattice study, for a theory with very small coupling\nconstants. We find perfect compatibility with next-to-leading order resummed\nperturbation theory, and demonstrate that ``inverse'' symmetry breaking can\nindeed take place at high temperatures."
    },
    {
        "anchor": "Hadronic observables from master-field simulations: Substantial progress has been made recently in the generation of master-field\nensembles. This has to be paired with efficient techniques to compute\nobservables on gauge field configurations with a large volume. Here we present\nthe results of the computation of hadronic observables, including hadron masses\nand meson decay constants, on large-volume and master-field ensembles with\nphysical volumes of up to $(18\\,\\mathrm{fm})^4$ and $m_\\pi L$ up to $25$,\nsimulated using $N_{\\mathrm{f}}=2+1$ stabilized Wilson fermions. We obtain\nsub-percent determinations from single gauge configurations with the combined\nuse of position-space techniques, volume averages and master-field error\nestimation.",
        "positive": "A fast minimal residual solver for overlap fermions: Computing quark propagators with overlap fermions requires the solution of a\nshifted unitary linear system. Jagels and Reichel have shown that for such\nsystems it is possible to construct a minimal residual algorithm by short\nrecurrences. The J\\\"ulich-Wuppertal group have found this algorithm to be the\nfastest among overlap solvers. In this paper we present a three-term recurrence\nfor the Arnoldi unitary process. Using the new recurrence we construct a\nminimal residual solver which is the fastest among all Krylov subspace\nalgorithms considered so far for the overlap inversion."
    },
    {
        "anchor": "Magnetic polarizability of hadrons from lattice QCD: We extract the magnetic polarizability from the quadratic response of a\nhadron's mass shift in progressively small static magnetic fields. The\ncalculation is done on a 24x12x12x24 lattice at a = 0.17 fm with an improved\ngauge action and the clover quark action. The results are compared to those\nfrom experiments and models where available.",
        "positive": "A Hybrid Strategy for the Lattice Evaluation of the Leading Order\n  Hadronic Contribution to $(g-2)_\u03bc$: The leading-order hadronic contribution to the muon anomalous magentic\nmoment, $a_\\mu^{\\rm LO,HVP}$, can be expressed as an integral over Euclidean\n$Q^2$ of the vacuum polarization function. We point out that a simple\ntrapezoid-rule numerical integration of the current lattice data is good enough\nto produce a result with a less-than-$1\\%$ error for the contribution from the\ninterval above $Q^2\\gtrsim 0.1-0.2\\ \\mathrm{GeV}^2$. This leaves the interval\nbelow this value of $Q^2$ as the one to focus on in the future. In order to\nachieve an accurate result also in this lower window $Q^2\\lesssim 0.1-0.2\\\n\\mathrm{GeV}^2$, we indicate the usefulness of three possible tools. These are:\nPad\\'{e} Approximants, polynomials in a conformal variable and a NNLO Chiral\nPerturbation Theory representation supplemented by a $Q^4$ term. The\ncombination of the numerical integration in the upper $Q^2$ interval together\nwith the use of these tools in the lower $Q^2$ interval provides a hybrid\nstrategy which looks promising as a means of reaching the desired goal on the\nlattice of a sub-percent precision in the hadronic vacuum polarization\ncontribution to the muon anomalous magnetic moment."
    },
    {
        "anchor": "Vectorized Cluster Search: Contrary to conventional wisdom, the construction of clusters on a lattice\ncan easily be vectorized, namely over each ``generation'' in a breadth first\nsearch. This applies directly to, e.g., the {\\it single cluster} variant of the\nSwendsen-Wang algorithm. On a Cray Y-MP, total CPU time was reduced by a factor\n3.5 -- 7 in actual applications.",
        "positive": "Lattice-based QCD equation of state at finite baryon density: Cluster\n  Expansion Model: The QCD equation of state at finite baryon density is studied in the\nframework of a Cluster Expansion Model (CEM), which is based on the fugacity\nexpansion of the net baryon density. The CEM uses the two leading Fourier\ncoefficients, obtained from lattice simulations at imaginary $\\mu_B$, as the\nonly model input and permits a closed analytic form. Excellent description of\nthe available lattice data at both $\\mu_B = 0$ and at imaginary $\\mu_B$ is\nobtained. We also demonstrate how the Fourier coefficients can be reconstructed\nfrom baryon number susceptibilities."
    },
    {
        "anchor": "Quark Contributions to Baryon Magnetic Moments in Full, Quenched and\n  Partially Quenched QCD: The chiral nonanalytic behaviour of quark-flavor contributions to the\nmagnetic moments of octet baryons are determined in full, quenched and\npartially-quenched QCD, using an intuitive and efficient diagrammatic\nformulation of quenched and partially-quenched chiral perturbation theory. The\ntechnique provides a separation of quark-sector magnetic-moment contributions\ninto direct sea-quark loop, valence-quark, indirect sea-quark loop and quenched\nvalence contributions, the latter being the conventional view of the quenched\napproximation. Both meson and baryon mass violations of SU(3)-flavor symmetry\nare accounted for. Following a comprehensive examination of the individual\nquark-sector contributions to octet baryon magnetic moments, numerous\nopportunities to observe and test the underlying structure of baryons and the\nnature of chiral nonanalytic behavior in QCD and its quenched variants are\ndiscussed. In particular, the valence u-quark contribution to the proton\nmagnetic moment provides the optimal opportunity to directly view nonanalytic\nbehavior associated with the meson cloud of full QCD and the quenched meson\ncloud of quenched QCD. The u quark in Sigma^+ provides the best opportunity to\ndisplay the artifacts of the quenched approximation.",
        "positive": "Coulomb corrections to pi-pi scattering: The relationship between finite volume multi-hadron energy levels and matrix\nelements and two particle scattering phase shifts and decays is well known, but\nthe inclusion of long range interactions such as QED is non-trivial. Inclusion\nof QED is an important systematic error correction to $K\\to\\pi\\pi$ decays. In\nthis talk, we present a method of including a truncated, finite-range Coulomb\ninteraction in a finite-volume lattice QCD calculation. We show how the\nomission caused by the truncation can be restored by an infinite-volume\nanalytic calculation so that the final result contains no power-law\nfinite-volume errors beyond those usually present in Luscher's finite-volume\nphase shift determination. This approach allows us to calculate the QED\ncorrected infinite-volume phase shift for $\\pi\\pi$ scattering in Coulomb gauge,\na necessary ingredient to $K\\to\\pi\\pi$, while neglecting the transverse\nradiation for now."
    },
    {
        "anchor": "Real-time simulation of the Schwinger effect with Matrix Product States: Matrix Product States (MPS) are used for the simulation of the real-time\ndynamics induced by an electric quench on the vacuum state of the massive\nSchwinger model. For small quenches it is found that the obtained oscillatory\nbehavior of local observables can be explained from the single-particle\nexcitations of the quenched Hamiltonian. For large quenches damped oscillations\nare found and comparison of the late time behavior with the appropriate Gibbs\nstates seems to give some evidence for the onset of thermalization. Finally,\nthe MPS real-time simulations are explicitly compared with the semi-classical\napproach and, as expected, agreement is found in the limit of large quenches.",
        "positive": "Hunting for the Conformal Window: Undeniably, the imminent activity of LHC and the quest for the nature of\nphysics beyond the standard model have raised renewed interest in the conformal\nand quasi-conformal behaviour of gauge field theories with matter content.\nTheoretically driven questions seem to now acquire a strong experimental appeal\nand might guide us towards a more realistic string theory to field theory\nconnection, originally inspired by the AdS/CFT conjecture. In this brief\nreport, we discuss the state of the art of our search for the conformal window\nin the SU(3) colour-gauge theory with fermions in the fundamental\nrepresentation."
    },
    {
        "anchor": "Lattice Planar QED in external magnetic field: We investigate planar Quantum ElectroDynamics (QED) with two degenerate\nstaggered fermions in an external magnetic field on the lattice. Our\npreliminary results indicate that in external magnetic fields there is\ndynamical generation of mass for two-dimensional massless Dirac fermions in the\nweak coupling region. We comment on possible implications to the quantum Hall\neffect in graphene.",
        "positive": "A New Determination of M_b Using Lattice QCD: Recent results from lattice QCD simulations provide a realistic picture,\nbased upon first principles, of~$\\Upsilon$ physics. We combine these results\nwith the experimentally measured mass of the $\\Upsilon$~meson to obtain an\naccurate and reliable value for the $b$-quark's pole mass. We use two different\nmethods, each of which yields a mass consistent with $M_b = 5.0(2)$~GeV. This\ncorresponds to a bare mass of $M_b^0 = 4.0(1)$~GeV in our lattice theory and an\n$\\msbar$~mass of $M_b^\\msbar(M_b)=4.0(1)$~GeV. We discuss the implications of\nthis result for the $c$-quark mass.\n*******************************************************************************\nTHIS IS THE VERSION WHICH WILL BE PUBLISHED IN PRL. SUBSTANTIAL MATERIAL HAS\nBEEN ADDED, INCLUDING RESULTS WITH DYNAMICAL FERMIONS AND A CALCULATION OF THE\nMSBAR MASS.\n*******************************************************************************"
    },
    {
        "anchor": "Status Report on Weak Matrix Element Calculations: This talk presents results of weak matrix elements calculated from\nsimulations done on 170 $32^3 \\times 64$ lattices at $\\beta = 6.0$ using\nquenched Wilson fermions. We discuss the extraction of pseudoscalar decay\nconstants $f_\\pi$, $f_K$, $f_D$, and $f_{D_s}$, the form-factors for the rare\ndecay $B \\to K^* \\gamma$, and the matrix elements of the 4-fermion operators\nrelevant to $B_K$, $B_7$, $B_8$. We present an analysis of the various sources\nof systematic errors, and show that these are now much larger than the\nstatistical errors for each of these observables. Our main results are\n$f_D=186(29) \\MeV$, $f_{D_s}=224(16) MeV$, $T_1=T_2=0.24(1)$, $B_K(NDR,\n2\\GeV)=0.67(9)$, and $B_8(NDR, 2\\GeV)=0.81(1)$.",
        "positive": "Rummukainen-Gottlieb's formula on two-particle system with different\n  mass: L\\\"uscher established a non-perturbative formula to extract the elastic\nscattering phases from two-particle energy spectrum in a torus using lattice\nsimulations. Rummukainen and Gottlieb further extend it to the moving frame,\nwhich is devoted to the system of two identical particles. In this work, we\ngeneralize Rummukainen-Gottlieb's formula to the generic two-particle system\nwhere two particles are explicitly distinguishable, namely, the masses of the\ntwo particles are different. The finite size formula are achieved for both\n$C_{4v}$ and $C_{2v}$ symmetries. Our analytical results will be very helpful\nfor the study of some resonances, such as kappa, vector kaon, and so on."
    },
    {
        "anchor": "QCD with colour-sextet quarks: We study QCD with 2 colour-sextet quarks as a model for walking Technicolor,\nusing lattice gauge theory simulations (RHMC) at finite temperature. Our goal\nis to determine if the massless theory is QCD-like (confining, with\nspontaneously-broken chiral symmetry) with a slowly varying coupling (walks) or\nif it is a conformal field theory. We do this by simulating the theory at\nfinite temperature and observing how the coupling at the chiral-symmetry\nrestoration temperature depends on the temporal extent $N_t$ of the lattice (in\nlattice units). If the theory is QCD-like, this coupling should approach zero\nin the large $N_t$ limit in the manner predicted by asymptotic freedom. If it\nis conformal, this coupling should approach a finite value in this limit, i.e.\nthe transition would be a bulk transition. We discuss new results at $N_t=6,8$\nand 12. These preliminary results indicate that the coupling does decrease with\nincreasing $N_t$, but it is unclear if this is consistent with asymptotic\nfreedom.",
        "positive": "HVP contribution of the light quarks to the muon $(g - 2)$ including\n  isospin-breaking corrections with Twisted-Mass fermions: We present a preliminary lattice calculation of the leading-order\nelectromagnetic and strong isospin-breaking corrections to the Hadronic Vacuum\nPolarization (HVP) contribution of the light quarks to the anomalous magnetic\nmoment of the muon. The results are obtained in the quenched-$QED$\napproximation using the $QCD$ gauge configurations generated by the European\nTwisted Mass Collaboration (ETMC) with $N_f = 2 + 1 + 1$ dynamical quarks, at\nthree values of the lattice spacing varying from $0.089$ to $0.062 ~\n\\mbox{fm}$, at several lattice volumes and with pion masses in the range $M_\\pi\n\\simeq 220 \\div 490 ~ \\mbox{MeV}$."
    },
    {
        "anchor": "``GLUELUMP'' SPECTRUM AND ADJOINT SOURCE POTENTIAL IN LATTICE QCD$_3$: We calculate the potential between ``quarks'' which are in the adjoint\nrepresentation of SU(2) color in the three-dimensional lattice theory. We work\nin the scaling region of the theory and at large quark separations $R$. We also\ncalculate the masses $M_{Qg}$ of color-singlet bound states formed by coupling\nan adjoint quark to adjoint glue (``gluelumps''). Good scaling behavior is\nfound for the masses of both magnetic (angular momentum $J=0$) and electric\n($J=1$) gluelumps, and the magnetic gluelump is found to be the lowest-lying\nstate. It is naively expected that the potential for adjoint quarks should\nsaturate above a separation $R_{\\rm scr}$ where it becomes energetically\nfavorable to produce a pair of gluelumps. We obtain a good estimate of the\nnaive screening distance $R_{\\rm scr}$. However we find little evidence of\nsaturation in the potential out to separations $R$ of about twice $R_{\\rm\nscr}$.",
        "positive": "Nonperturbative Casimir effect and monopoles: compact Abelian gauge\n  theory in two spatial dimensions: We demonstrate that Casimir forces associated with zero-point fluctuations of\nquantum vacuum may be substantially affected by the presence of dynamical\ntopological defects. In order to illustrate this nonperturbative effect we\nstudy the Casimir interactions between dielectric wires in a compact\nformulation of Abelian gauge theory in two spatial dimensions. The model\npossesses topological defects, instanton-like monopoles, which are known to be\nresponsible for nonperturbative generation of a mass gap and for a linear\nconfinement of electrically charged probes. Despite the model has no matter\nfields, the Casimir energy depends on the value of the gauge coupling constant.\nWe show, both analytically and numerically, that in the strong coupling regime\nthe Abelian monopoles make the Casimir forces short-ranged. Simultaneously,\ntheir presence increases the interaction strength between the wires at short\ndistances for certain range of values of the gauge coupling. The wires suppress\nmonopole density in the space between them compared to the density outside the\nwires. In the weak coupling regime the monopoles become dilute and the Casimir\npotential reduces to a known theoretical result which does not depend on the\ngauge coupling."
    },
    {
        "anchor": "Exploring the meson spectrum with twisted mass lattice QCD: Numerical simulations with access to all possible meson quantum numbers,\nJ^{PC}, are presented using two-flavor (up and down) quenched twisted mass\nlattice QCD with three different lattice spacings and four different quark\nmasses. The connection between the quantum numbers (P and C) and the symmetries\nof the twisted mass action are discussed, as is the connection between J and\nthe lattice rotation group, for the 400 operators used in this study. Curve\nfitting of this large data set is accomplished by using an evolutionary fitting\nalgorithm. Results are reported for conventional and exotic quantum numbers.",
        "positive": "The pseudoscalar meson electromagnetic form factor at high $Q^2$ from\n  full lattice QCD: We give an accurate determination of the vector (electromagnetic) form\nfactor, $F(Q^2)$, for a light pseudoscalar meson up to squared momentum\ntransfer $Q^2$ values of 6 $\\mathrm{GeV}^2$ for the first time from full\nlattice QCD, including $u$, $d$, $s$ and $c$ quarks in the sea at multiple\nvalues of the lattice spacing. Our results show good control of lattice\ndiscretisation and sea quark mass effects. We study a pseudoscalar meson made\nof valence $s$ quarks but the qualitative picture obtained applies also to the\n$\\pi$ meson, relevant to upcoming experiments at Jefferson Lab. We find that\n$Q^2F(Q^2)$ becomes flat in the region between $Q^2$ of 2 $\\mathrm{GeV}^2$ and\n6 $\\mathrm{GeV}^2$, with a value well above that of the asymptotic perturbative\nQCD expectation, but well below that of the vector-meson dominance pole form\nappropriate to low $Q^2$ values. Our calculations show that we can reach higher\n$Q^2$ values in future to shed further light on where the perturbative QCD\nresult emerges."
    },
    {
        "anchor": "Precision $\u03a5$ and $J/\u03a8$ spectroscopy with lattice NRQCD: We present new results on $\\Upsilon$ and $J/\\Psi$ spectroscopy using Lattice\nNRQCD. Charmonium results at quenched $\\beta$ = 5.7 show agreement with\nexperiment within understood systematic errors. We compare bottomonium results\nat quenched $\\beta$s 6.0 and 5.7 and show that the $1P-1S$ splitting scales\nwith $\\Lambda_V$, provided a correction is applied for the $\\cal{O}$$(a^{2})$\nerrors inherent in the gluon field configurations. There is a clear scale\ndifference between charmonium and bottomonium results in the quenched\napproximation. We compare quenched results at $\\beta$=6.0 for bottomonium with\nthose obtained on HEMCGC configurations at $\\beta$=5.6 using 2 light flavours\nof dynamical quarks. We show that extrapolations to $n_f$ = 3 are consistent\nwith experiment for the ratio of the $2S-1S$ splitting to that of the $1P-1S$.\nWe extract a value for the $\\Upsilon$-$\\eta_b$ splitting extrapolated to $n_f$\n= 3.",
        "positive": "The chiral limit in lattice QCD: It has been a big challenge for lattice QCD to simulate dynamical quarks near\nthe chiral limit. Theoretically, it is well-known that the naive chiral\nsymmetry cannot be realized on the lattice (the Nielsen-Ninomiya theorem). Also\npractically, the computational cost rapidly grows as the quark mass is reduced.\nThe JLQCD collaboration started a project to perform simulations with exact but\nmodified chiral symmetry using the the overlap-Dirac operator and the topology\nconserving action. The latter is helpful to reduce the numerical cost of the\ndynamical quarks. Our simulation of two-flavor QCD has been successful to\nreduce the sea quark mass down to a few MeV."
    },
    {
        "anchor": "Critical endpoint of (3+1)-dimensional finite density $Z_3$ gauge-Higgs\n  model with tensor renormalization group: The critical endpoint of the (3+1)-dimensional $Z_3$ gauge-Higgs model at\nfinite density is determined by the tensor renormalization group method. This\nwork is an extension of the previous one on the $Z_2$ model. The vital\ndifference between them is that the $Z_3$ model suffers from the sign problem,\nwhile the $Z_2$ model does not. We show that the tensor renormalization group\nmethod allows us to locate the critical endpoint for the $Z_3$ gauge-Higgs\nmodel at finite density, regardless of the sign problem.",
        "positive": "Toward the QCD $\u03b2$ Function with Dynamical Wilson Fermions: We present data for the scaling behavior of lattice QCD with two flavors of\nlight Wilson fermions. This is done by matching $\\pi$ n and $\\rho$ masses at\nthe two lattice sizes of $16^3\\times32 $ and $8^3\\times16$. We find that at\n$\\beta=6/g^2\\equiv5.3$ the matching does not occur over a range extending down\nto $\\beta=3.5$. For $\\beta=5.5$ matching may be achieved at $\\beta=4.8-4.9$,\nleading to a $\\Delta \\beta =0.6-0.7$ which is higher than the perturbative\n2-loop value of 0.45. In both cases we conclude that the simulations are very\nfar from the perturbative scaling region."
    },
    {
        "anchor": "Abelian Dominance in Chiral Symmetry Breaking: Calculations of the chiral condensate $\\langle \\bar{\\psi} \\psi \\rangle$ on\nthe lattice using staggered fermions and the Lanczos algorithm are presented.\nThree gauge fields are considered: the quenched non-Abelian field, the Abelian\nfield projected in the maximal Abelian gauge, and the monopole field further\ndecomposed from the Abelian field. The results show that the Abelian monopoles\nlargely reproduce the chiral condensate values of the full non-Abelian theory,\nboth in SU(2) and in SU(3).",
        "positive": "Large logarithmic rescaling of the scalar condensate: a subtlety with\n  substantial phenomenological implications: Lattice data, taken since 1998 near the critical line of a 4D Ising model,\nhave been supporting the large logarithmic rescaling of the scalar condensate\npredicted in the alternative description of symmetry breaking proposed by\nConsoli and Stevenson. This conclusion has been challenged in a recent paper by\nBalog et al. In this paper we respond to the criticism of these authors,\nrecapitulate the theoretical and numerical evidences in favour of the\nalternative interpretation of `triviality' and reiterate our conclusion:\n`triviality', by itself, cannot be used to place upper bounds on the Higgs\nboson mass."
    },
    {
        "anchor": "Toward Lattice QCD On Billion Core Approximate Computers: We present evidence of the feasibility of using billion core approximate\ncomputers to run simple U(1) sigma models, and discuss how the approach might\nbe extended to Lattice Quantum Chromodynamics (LQCD) models. This work is\nmotivated by the extreme time, power, and cost needed to run LQCD on current\ncomputing hardware. We show that, using massively parallel approximate\nhardware, at least some models can run with great speed and power efficiency\nwithout sacrificing accuracy. As a test of accuracy, a 32 x 32 x 32 U(1) sigma\nmodel yielded similar results using floating point and approximate\nrepresentations for the spins. A 20 million point 3D model, run on a\n34,000-core single-board prototype approximate computer, showed encouraging\naccuracy with a ~750 times improvement in speed and ~2500 times improvement in\nspeed/watt compared to a traditional CPU. These results suggest there is value\nin future research to determine whether similar speed-ups and accuracies are\npossible running full LQCD on the compact billion-core approximate computing\nsystems that are now practical.",
        "positive": "Overview from lattice QCD: I review recent Lattice results. In particular, the confinement mechanism and\nstring breaking, glueballs and hybrid mesons as well as light hadron\nspectroscopy are discussed."
    },
    {
        "anchor": "Hadron spectroscopy and few-body dynamics from lattice QCD: Despite quantum chromodynamics (QCD) being established as the theory of the\nstrong interaction and its many successes since then, significant challenges in\nour understanding of hadron physics remain. The lack of a full understanding\nfor how the observed hadrons arise from the quark and gluon degrees of freedom\nwhich define QCD represents a real challenge in connecting the theory to\nexperiment. In particular, the rich spectrum of hadrons marks a significant gap\nin our understanding, as no model can currently explain all observed hadrons\nand QCD itself has only been used to study a small subset of the full spectrum.\nThe significant hurdle for using QCD directly is due to the non-perturbative\nnature of the theory at low energies, requiring methods like lattice QCD. Here,\nthe spectrum of hadrons and how it relates to few-body dynamics is reviewed,\nwith a focus on state-of-the-art methods for their study through lattice QCD.",
        "positive": "The QCD vacuum wave functional and confinement in Coulomb gauge: We report results on the Coulomb-gauge ghost propagator and the color-Coulomb\npotential computed in two lattice gauge-field ensembles: (1) configurations\nderived from our recently proposed Yang-Mills vacuum wave functional in 2+1\ndimensions, and (2) lattices generated by Monte Carlo simulations of the\nthree-dimensional Euclidean SU(2) lattice gauge theory with the Wilson action.\nWe observe remarkable agreement between the ghost propagators in both\nensembles, but some differences in the potentials. Those originate from rare\nconfigurations with very small values of the lowest eigenvalue of the\nCoulomb-gauge Faddeev-Popov operator. If the same cuts on such exceptional\nconfigurations are applied in both ensembles, then the color-Coulomb potentials\nare also in reasonably good agreement."
    },
    {
        "anchor": "Hyper-Systolic Parallel Computing: A new class of parallel algorithms is introduced that can achieve a\ncomplexity of O(n^3/2) with respect to the interprocessor communication, in the\nexact computation of systems with pairwise mutual interactions of all elements.\nHitherto, conventional methods exhibit a communicational complexity of O(n^2).\nThe amount of computation operations is not altered for the new algorithm which\ncan be formulated as a kind of h-range problem, known from the mathematical\nfield of Additive Number Theory. We will demonstrate the reduction in\ncommunicational expense by comparing the standard-systolic algorithm and the\nnew algorithm on the connection machine CM5 and the CRAY T3D. The parallel\nmethod can be useful in various scientific and engineering fields like exact\nn-body dynamics with long range forces, polymer chains, protein folding or\nsignal processing.",
        "positive": "The lattice gluon propagator in renormalizable $\u03be$ gauges: We study the SU(3) gluon propagator in renormalizable $R_\\xi$ gauges\nimplemented on a symmetric lattice with a total volume of (3.25 fm)$^4$ for\nvalues of the guage fixing parameter up to $\\xi=0.5$. As expected, the\nlongitudinal gluon dressing function stays constant at its tree-level value\n$\\xi$. Similar to the Landau gauge, the transverse $R_\\xi$ gauge gluon\npropagator saturates at a non-vanishing value in the deep infrared for all\nvalues of $\\xi$ studied. We compare with very recent continuum studies and\nperform a simple analysis of the found saturation with a dynamically generated\neffective gluon mass."
    },
    {
        "anchor": "B- and D-meson leptonic decay constants and quark masses from\n  four-flavor lattice QCD: We describe a recent lattice-QCD calculation of the leptonic decay constants\nof heavy-light pseudoscalar mesons containing charm and bottom quarks and of\nthe masses of the up, down, strange, charm, and bottom quarks. Results for\nthese quantities are of the highest precision to date. Calculations use 24\nisospin-symmetric ensembles of gauge-field configurations with six different\nlattice spacings as small as approximately 0.03 fm and several values of the\nlight quark masses down to physical values of the average up- and\ndown-sea-quark masses. We use the highly-improved staggered quark (HISQ)\nformulation for valence and sea quarks, including the bottom quark. The\nanalysis employs heavy-quark effective theory (HQET). A novel HQET method is\nused in the determination of the quark masses.",
        "positive": "Phase structure of 3D Z(N) lattice gauge theories at finite temperature: We perform a numerical study of the phase transitions in three-dimensional\nZ(N) lattice gauge theories at finite temperature for N>4. Using the dual\nformulation of the models and a cluster algorithm we locate the position of the\ncritical points and study the critical behavior across both phase transitions\nin details. In particular, we determine various critical indices, compute the\naverage action and the specific heat. Our results are consistent with the two\ntransitions being of infinite order. Furthermore, they belong to the\nuniversality class of two-dimensional Z(N) vector spin models."
    },
    {
        "anchor": "Two-nucleon scattering in multiple partial waves: We determine scattering phase shifts for S,P,D, and F partial wave channels\nin two-nucleon systems using lattice QCD methods. We use a generalization of\nLuscher's finite volume method to determine infinite volume phase shifts from a\nset of finite volume ground- and excited-state energy levels on two volumes,\nV=(3.4 fm)^3 and V=(4.5 fm)^3. The calculations are performed in the\nSU(3)-flavor limit, corresponding to a pion mass of approximately 800 MeV. From\nthe energy dependence of the phase shifts we are able to extract scattering\nparameters corresponding to an effective range expansion.",
        "positive": "Bound H-dibaryon from Full QCD Simulations on the Lattice: Using a new method recently proposed by the HAL QCD collaboration to study\nhadron interactions in lattice QCD, we investigate a possibility for an\nexistence of the H-dibaryon in the flavor SU(3) symmetric world. A potential\nfor the flavor-singlet baryon-baryon channel is derived from the\nNambu-Bethe-Salpeter wave function, and the elusive H-dibaryon is shown to be a\nbound state, with the binding energy of 20--50 MeV for the pseudo-scalar meson\nmasses in the range that 469--1171 MeV."
    },
    {
        "anchor": "Full simulation of chiral Random Matrix Theory at non-zero chemical\n  potential by Complex Langevin: It is demonstrated that the complex Langevin method can simulate chiral\nrandom matrix theory at non-zero chemical potential. The successful match with\nthe analytic prediction for the chiral condensate is established through a\nshift of matrix integration variables and choosing a polar representation for\nthe new matrix elements before complexification. Furthermore, we test the\nproposal to work with a Langevin-time dependent quark mass and find that it\nallows us to control the fluctuations of the phase of the fermion determinant\nthroughout the Langevin trajectory.",
        "positive": "Asymptotic behavior of Nambu-Bethe-Salpeter wave functions for scalar\n  systems with a bound state: We study the asymptotic behaviors of the Nambu-Bethe-Salpeter (NBS) wave\nfunctions, which are important for the HAL QCD potential method to extract\nhadron interactions, in the case that a bound state exists in the system. We\nconsider the complex scalar particles, two of which lead to the formation of a\nbound state. In the case of the two-body system, we show that the NBS wave\nfunctions for the bound state as well as scattering states in the asymptotic\nregion behave like the wave functions in quantum mechanics, which carry the\ninformation of the binding energy as well as the scattering phase shift. This\nanalysis theoretically establishes under some conditions that the HAL QCD\npotential can correctly reproduce not only the scattering phase shift but also\nthe binding energy. As an extension of the analysis, we also study the\nasymptotic behaviors of all possible NBS wave functions in the case of the\nthree-body systems, two of which can form a bound states."
    },
    {
        "anchor": "Topology in full QCD at high temperature: a multicanonical approach: We investigate the topological properties of $N_f = 2+1$ QCD with physical\nquark masses, at temperatures around 500 MeV. With the aim of obtaining a\nreliable sampling of topological modes in a regime where the fluctuations of\nthe topological charge $Q$ are very rare, we adopt a multicanonical approach,\nadding a bias potential to the action which enhances the probability of\nsuppressed topological sectors. This method permits to gain up to three orders\nof magnitude in computational power in the explored temperature regime. Results\nat different lattice spacings and physical spatial volumes reveal no\nsignificant finite size effects and the presence, instead, of large finite\ncut-off effects, with the topological susceptibility which decreases by 3-4\norders of magnitude while moving from $a \\simeq 0.06$ fm towards the continuum\nlimit. The continuum extrapolation is in agreeement with previous lattice\ndeterminations with smaller uncertainties but obtained based on ansatzes\njustified by several theoretical assumptions. The parameter $b_2$, related to\nthe fourth order coefficient in the Taylor expansion of the free energy density\n$f(\\theta)$, has instead a smooth continuum extrapolation which is in agreement\nwith the dilute instanton gas approximation (DIGA); moreover, a direct\nmeasurement of the relative weights of the different topological sectors gives\nan even stronger support to the validity of DIGA.",
        "positive": "Comparison of the O(3) Bootstrap $\u03c3$-Model with the Lattice\n  Regularization at Low Energies: The renormalized coupling $\\gr$ defined through the connected 4-point\nfunction at zero external momentum in the non-linear O(3) sigma-model in two\ndimensions, is computed in the continuum form factor bootstrap approach with\nestimated error $\\sim 0.3%$. New high precision data are presented for $\\gr$ in\nthe lattice regularized theory with standard action for nearly thermodynamic\nlattices $L/\\xi\\sim 7$ and correlation lengths $\\xi$ up to $\\sim 122$ and with\nthe fixed point action for correlation lengths up to $\\sim 12$. The agreement\nbetween the form factor and lattice results is within $\\sim 1%$. We also\nrecompute the phase shifts at low energy by measuring the two-particle energies\nat finite volume, a task which was previously performed by L\\\"uscher and Wolff\nusing the standard action, but this time using the fixed point action.\nExcellent agreement with the Zamolodchikov S-matrix is found."
    },
    {
        "anchor": "A Lattice Determination of Light Quark Masses: A fully non-perturbative lattice determination of the up/down and strange\nquark masses is given for quenched QCD using both, $O(a)$ improved Wilson\nfermions and ordinary Wilson fermions. For the strange quark mass with $O(a)$\nimproved fermions we obtain $m^{\\msbar}_s(\\mu=2 {GeV}) = 105(4) {MeV}$, using\nthe interquark force scale $r_0$. Due to quenching problems fits are only\npossible for quark masses larger than the strange quark mass. If we extrapolate\nour fits to the up/down quark mass we find for the average mass\n$m^{\\msbar}_l(\\mu=2 {GeV}) = 4.4(2) {MeV}$.",
        "positive": "Wave functions for Hamiltonian Lattice Gauge Theory: We study four dimensional SU(2) lattice gauge theory in the Hamiltonian\nformalism by Green's Function Monte Carlo methods. A trial ground state wave\nfunction is introduced to improve the configuration sampling and we discuss the\ninterplay between its complexity and the simulation systematic errors. As a\ncase study, we compare the leading strong coupling approximation and an\nimproved 4 parameters wave function with 1X1 and 1X2 plaquette terms. Our\nnumerical results favors the second option."
    },
    {
        "anchor": "Stochastic All-to-All Propagators for Baryon Correlators: The effectiveness of various dilution schemes in the evaluation of baryonic\ntwo-point functions is compared. The error of a representative set of\nobservables as a function of the number of Dirac matrix inversions is used as a\nbasis for comparison. To achieve an equivalent reduction in error, we\ndemonstrate that an increase in the number of dilution projectors on a single\nnoise source usually requires fewer inversions than the use of multiple noise\nsources. This exploratory study was performed on 100 quenched gauge\nconfigurations and will be applied to the calculation of low-lying hadron\nspectra.",
        "positive": "Physical properties of Polyakov loop geometrical clusters in SU(2)\n  gluodynamics: We apply the liquid droplet model to describe the clustering phenomenon in\nSU(2) gluodynamics, especially, in the vicinity of the deconfinement phase\ntransition. In particular, we analyze the size distributions of clusters formed\nby the Polyakov loops of the same sign. Within such an approach this phase\ntransition can be considered as the transition between two types of liquids\nwhere one of the liquids (the largest droplet of a certain Polyakov loop sign)\nexperiences a condensation, while the other one (the next to largest droplet of\nopposite Polyakov loop sign) evaporates. The clusters of smaller sizes form two\naccompanying gases, and their size distributions are described by the liquid\ndroplet parameterization. By fitting the lattice data we have extracted the\nvalue of Fisher exponent $\\tau =$ 1.806 $\\pm$ 0.008. Also we found that the\ntemperature dependences of the surface tension of both gaseous clusters are\nentirely different below and above the phase transition and, hence, they can\nserve as an order parameter. The critical exponents of the surface tension\ncoefficient in the vicinity of the phase transition are found. Our analysis\nshows that the temperature dependence of the surface tension coefficient above\nthe critical temperature has a $T^2$ behavior in one gas of clusters and $T^4$\nin the other one."
    },
    {
        "anchor": "Strong coupling constant from moments of quarkonium correlators: I review the determination of the strong coupling constant from moments of\nquarkonium correlators calculated on the lattice. I discuss different sources\nof systematic errors in such calculations.",
        "positive": "Topological Phases in Neuberger-Dirac operator: The response of the Neuberger-Dirac fermion operator $D=\\Id + V$ in the\ntopologically nontrivial background gauge field depends on the negative mass\nparameter $m_0$ in the Wilson-Dirac fermion operator $D_w$ which enters $D$\nthrough the unitary operator $V = D_w (D_w^{\\dagger} D_w)^{-1/2}$. We classify\nthe topological phases of $D$ by comparing its index to the topological charge\nof the smooth background gauge field. An exact discrete symmetry in the\ntopological phase diagram is proved for any gauge configurations. A formula for\nthe index of D in each topological phase is derived by obtaining the total\nchiral charge of the zero modes in the exact solution of the free fermion\npropagator."
    },
    {
        "anchor": "Fermion decoupling and the axial anomaly on the lattice: By an explicit calculation of the continuum limit of the triangle graph\namplitude in lattice QED we show that in the axial Ward identity the ABJ\nanomaly exactly cancels the pseudoscalar density term in the limit of infinite\nfermion mass $m$. The result, a reflection of decoupling of the heavy fermion,\nprovides a convenient framework for computing the flavor-singlet or U(1) axial\nanomaly in non-Abelian gauge theories on lattice. Our calculations on the\nlattice are performed using Wilson fermions but the results are general.",
        "positive": "$R(J/\u03c8)$ and $B_c^- \\rightarrow J/\u03c8\\ell^-\\bar\u03bd_\\ell$ Lepton\n  Flavor Universality Violating Observables from Lattice QCD: We use our lattice QCD computation of the $B_c\\rightarrow J/\\psi$ form\nfactors to determine the differential decay rate for the semitauonic decay\nchannel and construct the ratio of branching fractions $R(J/\\psi) =\n\\mathcal{B}(B_c^- \\rightarrow J/\\psi \\tau^-\\bar{\\nu}_\\tau)/\\mathcal{B}(B_c^-\n\\rightarrow J/\\psi \\mu^-\\bar{\\nu}_\\mu)$. We find $R(J/\\psi) = 0.2582(38)$ and\ngive an error budget. We also extend the relevant angular observables, which\nwere recently suggested for the study of lepton flavor universality violating\neffects in $B\\rightarrow D^*\\ell\\nu$, to $B_c \\rightarrow J/\\psi\\ell\\nu$ and\nmake predictions for their values under different new physics scenarios."
    },
    {
        "anchor": "Convergent perturbation theory for lattice models with fermions: The standard perturbation theory in QFT and lattice models leads to\nasymptotic expansions. However, an appropriate regularization of the path or\nlattice integrals allows one to construct convergent series with an infinite\nradius of the convergence. In the earlier studies this approach was applied to\nthe purely bosonic systems. Here, using bosonization, we develop the convergent\nperturbation theory for a toy lattice model with interacting fermionic and\nbosonic fields.",
        "positive": "Equation of State for SU(3) Gauge Theory via the Energy-Momentum Tensor\n  under Gradient Flow: The energy density and the pressure of SU(3) gauge theory at finite\ntemperature are studied by direct lattice measurements of the renormalized\nenergy-momentum tensor obtained by the gradient flow. Numerical analyses are\ncarried out with $\\beta=6.287$--$7.500$ corresponding to the lattice spacing\n$a= 0.013$--$0.061\\,\\mathrm{fm}$. The spatial (temporal) sizes are chosen to be\n$N_s= 64$, $96$, $128$ ($N_{\\tau}=12$, $16$, $20$, $22$, $24$) with the aspect\nratio, $5.33 \\le N_s/N_{\\tau} \\le 8$. Double extrapolation, $a\\rightarrow 0$\n(the continuum limit) followed by $t\\rightarrow 0$ (the zero flow-time limit),\nis taken using the numerical data. Above the critical temperature, the\nthermodynamic quantities are obtained with a few percent precision including\nstatistical and systematic errors. The results are in good agreement with\nprevious high-precision data obtained by using the integral method."
    },
    {
        "anchor": "The Weak-Coupling Limit of 3D Simplicial Quantum Gravity: We investigate the weak-coupling limit, kappa going to infinity, of 3D\nsimplicial gravity using Monte Carlo simulations and a Strong Coupling\nExpansion. With a suitable modification of the measure we observe a transition\nfrom a branched polymer to a crinkled phase. However, the intrinsic geometry of\nthe latter appears similar to that of non-generic branched polymer, probable\nexcluding the existence of a sensible continuum limit in this phase.",
        "positive": "Width of the Confining String: We critically reconsider our recent observation of confining string shrinkage\nin pure glue SU(2) lattice gauge theory near the continuum limit. Using the\nadvanced numerical techniques we argue that imperfect overlap with the string\nground state and corresponding ambiguities in T->\\infty extrapolation are\nlikely to be the cause of the observed scaling violations. In particular, even\nin the limit of large Euclidean times the string shrinkage is apparent in\ntorelon correlation function, however, in this case the best relevant overlap\nwe could attain is of order 50%. To the contrary, when the ground state is\nselected properly the string width scales in physical units being ~0.3 fm for 1\nfm long confining string."
    },
    {
        "anchor": "Screening masses in strong external magnetic fields: We present results for the (color)magnetic and (color)electric screening\nmasses of the Quark-Gluon Plasma in the presence of an external magnetic field.\nThe screening masses are extracted from the correlators of Polyakov loops,\ndetermined by lattice QCD simulations at the physical point. We explore\ntemperatures in the range $200\\,\\mathrm{MeV}\\lesssim T\\lesssim\n330\\,\\mathrm{MeV}$ and magnetic field intensities up to $|e|B \\sim\n1.3\\,\\mathrm{GeV}^2$. We find that both screening masses are increasing\nfunctions of the magnetic field and that the dependence on $B$ becomes weaker\nfor larger temperatures. In the case of the magnetic screening mass a slight\nanisotropy is also observable.",
        "positive": "Contamination of Excited States in Quenched QCD Hadron Propagators: Quenched QCD hadron spectrum is calculated with Wilson's quark action at\n$\\beta=5.85$ and 6.0 on a $24^3 \\times 54$ lattice. We discuss the problem of\nwhether we have extracted the mass of the ground state at these $\\beta$'s\nwithout contamination of the excited states. We show that the masses of the\nfirst excited states turn out to be consistent with experiment when we are able\nto obtain the propagators up to the large time slice region where the\npropagators take the asymptotic forms of the ground states."
    },
    {
        "anchor": "Critical endpoint of finite temperature phase transition for three\n  flavor QCD: We investigate the critical endpoint of finite temperature phase transition\nof $N_f=3$ QCD at zero chemical potential. We employ the renormalization-group\nimproved Iwasaki gauge action and non-perturbatively $O(a)$-improved\nWilson-clover fermion action. The critical endpoint is determined by using the\nintersection point of kurtosis for the temporal size $N_t$=4, 6, 8. Spatial\nsizes of $N_l$=6-16 ($N_t$=4), 10-24 ($N_t$=6), and 12-24 ($N_t$=8) are\nemployed. We find that $N_t$=4 is out of the scaling region. Using results for\n$N_t$=6 and 8, and making linear extrapolations in $1/N_t^2$, we obtain\n$\\sqrt{t_0}T_{\\rm E}=0.0975(14)(8)$, $\\sqrt{t_0}m_{\\rm PS,E}=0.2254(52)(105)$\nand $m_{\\rm PS,E}/T_{\\rm E}=2.311(63)(13)$, where the first error is\nstatistical error, the second error is systematic error, and $m_{\\rm PS}$ is\nthe pseudo scalar meson mass. If one uses $1/\\sqrt{t_0}=1.347(30)$ GeV reported\nby Borsanyi et al., one finds $T_{\\rm E}=131(2)(1)(3)$ MeV, $m_{\\rm\nPS,E}=304(7)(14)(7)$ MeV and $m_{\\rm PS,E}/m_{\\rm PS,E}^{\\rm phys,\nsym}=0.739(17)(34)(17)$, where the third error comes from error of $\\sqrt{t_0}$\nand $m_{\\rm PS}^{\\rm phys, sym}=\\sqrt{(m_\\pi^2+2m_K^2)/3}$. Our current\nestimation of $\\sqrt{t_0}m_{\\rm PS,E}$ in the continuum limit is about 25%\nsmaller than the SU(3) symmetric point.",
        "positive": "The path from finite to infinite volume: Hadronic observables from\n  lattice QCD: Standard Model determinations of properties of strongly interacting systems\nof hadrons have become possible with the powerful method of lattice quantum\nchromodynamics (LQCD), a method with growing applicability and reliability.\nWhile growth in computational power and innovations in algorithmic and\ncomputational approaches have been essential in advancing the state of the\nfield, conceptual and formal developments have played a crucial role in turning\nthe output of LQCD computations to phenomenologically valuable results. From\nthe invention of finite-volume technology to access physical observables by\nMartin L\\\"uscher over three decades ago to date, this field has grown in scope\nand complexity, enabling studies of scattering amplitudes and reaction rates,\nas well as spectroscopy of excited states of quantum chromodynamics (QCD) and\nresonances. Further, LQCD studies are augmented with the inclusion of quantum\nelectrodynamics (QED), and subtleties related to the finite volume of systems\nin presence of QED have been understood and largely controlled. In this talk, I\nfocus on selected developments to give a taste of the status of the field\nconcerning the mapping between the finite and infinite-volume physics and its\nstate-of-the-art applications."
    },
    {
        "anchor": "Masses and decay constants of the $D_{s0}^*(2317)$ and $D_{s1}(2460)$\n  from $N_f=2$ lattice QCD close to the physical point: We perform a high statistics study of the $J^{P}=0^{+}$ and $1^{+}$\ncharmed-strange mesons, $D_{s0}^*(2317)$ and $D_{s1}(2460)$, respectively. The\neffects of the nearby $DK$ and $D^{*}K$ thresholds are taken into account by\nemploying the corresponding four quark operators. Six ensembles with $N_f=2$\nnon-perturbatively ${\\cal O}(a)$ improved clover Wilson sea quarks at $a=0.07$\nfm are employed, covering different spatial volumes and pion masses: linear\nlattice extents $L/a=24,32,40,64$, equivalent to 1.7 fm to 4.5 fm, are realised\nfor $m_{\\pi}=290$ MeV and $L/a=48,64$ or 3.4 fm and 4.5 fm for an almost\nphysical pion mass of $150$ MeV. Through a phase shift analysis and the\neffective range approximation we determine the scattering lengths, couplings to\nthe thresholds and the infinite volume masses. Differences relative to the\nexperimental values are observed for these masses, however, this is likely to\nbe due to discretisation effects as spin-averaged quantities and splittings are\nreasonably compatible with experiment. We also compute the weak decay constants\nof the scalar and axialvector and find $f_V^{0^+}=114(2)(0)(+5)(10)$ MeV and\n$f_A^{1^+}=194(3)(4)(+5)(10)$ MeV, where the errors are due to statistics,\nrenormalisation, finite volume and lattice spacing effects.",
        "positive": "A lattice QCD study of generalized gluelumps: Proposals for physics beyond the standard model often include new colored\nparticles at or beyond the scale of electroweak symmetry breaking. Any new\nparticle with a sufficient lifetime will bind with standard model gluons and\nquarks to form a spectrum of new hadrons. Here we focus on colored particles in\nthe octet, decuplet, 27-plet, 28-plet and 35-plet representations of SU(3)\ncolor because these can form hadrons without valence quarks. In every case,\nlattice creation operators are constructed for all angular momentum, parity and\ncharge conjugation quantum numbers. Computations with fully-dynamical lattice\nQCD configurations produce numerical results for mass splittings within this\nnew hadron spectrum. A previous quenched lattice study explored the octet case\nfor certain quantum number choices, and our findings provide a reassessment of\nthose early results."
    },
    {
        "anchor": "Simulating the Random Surface representation of Abelian Gauge Theories: We present a Monte-Carlo algorithm for the simulation of the all-order strong\ncoupling expansion of the Z2 gauge theory. This random surface ensemble is\nequivalent to the standard formulation, but allows to measure some quantities,\nlike Polyakov loop correlators or excess free energies, with an accuracy that\ncould not have been easily achieved with traditional simulation methods. One\ninteresting application of the algorithm is the investigation of effective\nstring theories.",
        "positive": "Does the 2d Higgs-Yukawa Model Have a Symmetric Phase at Small Yukawa\n  Coupling Region?: We show that at arbitrary value of the scalar self coupling and small Yukawa\ncoupling $y$ the 2d Higgs-Yukawa model with Z(2) symmetry remains in the broken\nphase and the model is asymptotically free: $y \\to 0$ as the cut-off $\\Lambda\n\\to \\infty$. This is in agreement with a recent conjecture based on numerical\nsimulation results."
    },
    {
        "anchor": "Mass Gap, Abelian Dominance and Vortex Dynamics in SU(2) Spin Model: We discuss a new approach to the investigation of the nature of the mass gap\nin spin systems with continuous global symmetries which is much analogous to\nthe method of abelian projection in the gauge theories. We suggest that the\nabelian degrees of freedom, in particular, abelian vortices are responsible for\nthe mass gap generation phenomena in the non-abelian spin systems. To check our\nhypothesis we study numerically the three-dimensional SU(2) spin model in the\nMaximal Abelian projection. We find that the abelian mass gap in the projected\ntheory coincides with the full non-abelian mass gap within numerical errors.\nThe study of the percolation properties of the abelian vortex trajectories\nshows that the phase transition and the mass gap generation in the 3D SU(2)\nspin model are driven by the abelian vortex condensation.",
        "positive": "Topics of monopole dynamics in gluodynamics: Three topics of monopole dynamics in gluodynamics are presented. 1)Gauge\n(in)dependence of the monopole effective action (S.Ito, T.W.Park, T.Suzuki):\nFour different abelian projections are studied. MA and Laplacian abelian gauges\nshow almost the same renormalization flow and renormalized trajectory. 2)The\nquantized dual abelian Higgs model (DAH) derived from SU(2) gluodynamics and\nits vacuum structure (Y.Koma, E.-M.Ilgenfritz, T.Suzuki,M.I.Polikarpov):\nMonte-Carlo analysis of DAH is done. The quantum average of the dual field\nstrength shows a flux tube profile similar to the color-electric field profile\nmeasured in SU(2) gluodynamics. 3)Lattice instanton action from 3D SU(2)\nGeorgi-Glashow model (GG)$_3$ (T.Yazawa, T.Suzuki): (GG)$_3$ is studied on the\nlattice in the London limit. We determine an effective instanton action both in\nunitary and MA gauges. For some range of parameters, we obtain almost perfect\nactions which look the same in both gauges (gauge independence) and which\nreproduce well the string tension."
    },
    {
        "anchor": "Canonical simulations of supersymmetric SU(N) Yang-Mills quantum\n  mechanics: The fermion loop formulation naturally separates partition functions into\ntheir canonical sectors. Here we discuss various strategies to make use of this\nfor supersymmetric SU(N) Yang-Mills quantum mechanics obtained from dimensional\nreduction in various dimensions and present numerical results for the separate\ncanonical sectors with fixed fermion numbers. We comment on potential problems\ndue to the sign of the contributions from the fermions and due to flat\ndirections.",
        "positive": "Bump of sound velocity in dense 2-color QCD: We obtain the equation of state (EoS) and the sound velocity for 2-color QCD\nat low temperature and high density and find that in the superfluid phase,\n$c_s^2/c^2 >1/3$, where $1/3$ is the value at the relativistic limit. Several\nindependent Monte Carlo studies on 2-color QCD have been conducted intensively\nin recent years. These works have shown a clear evidence of phase transition\nbetween hadronic and superfluid phases. In our paper[1], we have investigated\nthe EoS and sound velocity in both phases. Our result is consistent with chiral\nperturbation theory in a low $\\mu$ regime of the superfluid phase including the\nBose-Einstein condensed phase, and shows a peak of sound velocity in the\nhigh-density BCS phase. We also give detailed simulation results and a comment\non the holography bound in this proceedings."
    },
    {
        "anchor": "Perturbative Renormalization of Weak-Hamiltonian Four-Fermion Operators\n  with Overlap Fermions: The renormalization of the most general dimension-six four-fermion operators\nwithout power subtractions is studied at one loop in lattice perturbation\ntheory using overlap fermions. As expected, operators with different chirality\ndo not mix among themselves and parity-conserving and parity-violating\nmultiplets renormalize in the same way. The renormalization constants of\nunimproved and improved operators are also the same. These mixing factors are\nnecessary to determine physical matrix elements relevant to many\nphenomenological applications of weak interactions. The most important are the\nK0-K0bar and B0-B0bar mixings in the Standard Model and beyond, the Delta I\n=1/2 rule and epsilon'/epsilon.",
        "positive": "Charmonium with three flavors of dynamical quarks: We present a calculation of the charmonium spectrum with three flavors of\ndynamical staggered quarks from gauge configurations that were generated by the\nMILC collaboration. We use the Fermilab action for the valence charm quarks.\nOur calculation of the spin-averaged 1P--1S and 2S--1S splittings yields a\ndetermination of the strong coupling, with $\\ams(M_Z) = 0.119 (4)$."
    },
    {
        "anchor": "NRQCD on an anisotropic lattice: We present preliminary results for the Upsilon spectrum on an anisotropic\nlattice using the improved O(mv^6) NRQCD Hamiltonian. We find accurate results\ncan be obtained in moderate computer times and that they agree with earlier\nresults on an isotropic lattice.",
        "positive": "Two-flavor lattice QCD study of the axial charges of N(1535) and N(1650): We show the first lattice QCD results on the axial charges $g_A^{N^*N^*}$ of\n$N^*(1535)$ and $N^*(1650)$. The measurements are performed with two flavors of\ndynamical quarks employing the renormalization-group improved gauge action at\n$\\beta$=1.95 and the mean-field improved clover quark action with the hopping\nparameters, $\\kappa$=0.1375, 0.1390 and 0.1400. We construct 2$\\times$2\ncorrelation matrices and diagonalize them so that the signals of $N^*(1535)$\nand $N^*(1650)$ are properly separated. Wraparound contributions in the\ncorrelator, which can be another source of signal contaminations, are\neliminated by imposing the Dirichlet boundary condition in the temporal\ndirection. The axial charge of $N^*(1535)$ is found to take small values as\n$g_A^{N^*N^*}\\sim {\\mathcal O}(0.1)$, whereas that of $N^*(1650)$ is\napproximately 0.5, which is almost independent of quark masses and consistent\nwith the predictions by the naive nonrelativistic quark model."
    },
    {
        "anchor": "$1^{-+}$ Hybrid in $J/\u03c8$ Radiative Decays from Lattice QCD: We present the first theoretical prediction of the production rate of\n$1^{-+}$ light hybrid meson $\\eta_1$ in $J/\\psi$ radiative decays. In the\n$N_f=2$ lattice QCD formalism with the pion mass $m_\\pi\\approx 350$ MeV, the\nrelated electromagnetic multipole form factors are extracted from the\nthree-point functions that involve necessarily quark annihilation diagrams,\nwhich are calculated through the distillation method. The partial width of\n$J/\\psi\\to \\gamma \\eta_1$ is determined to be $2.29(77)~\\mathrm{eV}$ at the\n$\\eta_1$ mass $m_{\\eta_1}=2.23(4)$ GeV. If $\\eta_1$ corresponds to the recently\nobserved $\\eta_1(1855)$ in the process $J/\\psi\\to \\gamma\\eta_1(1855)\\to \\gamma\n\\eta\\eta'$ by BESIII, then the branching fraction $\\mathrm{Br}(J/\\psi\\to\n\\gamma\\eta_1(1855))$ is estimated to be $6.2(2.2)\\times 10^{-5}$, which implies\n$\\mathrm{Br}(\\eta_1(1855)\\to \\eta\\eta')\\sim 4.3\\%$.",
        "positive": "Exact Chiral Symmetry for Domain Wall Fermions with Finite L_s: We show how the standard domain wall action can be simply modified to allow\narbitrarily exact chiral symmetry at finite fifth dimensional extent $L_s$. We\nnote that the method can be used for both quenched and dynamical calculations.\nWe test the method using smooth and thermalized gauge field configurations. We\nalso make comparisons of the performance (cost) of the domain wall operator for\nspectroscopy compared to other methods such as the overlap-Dirac operator and\nfind both methods are comparable in cost."
    },
    {
        "anchor": "Unphysical poles and dispersion relations for M\u00f6bius domain-wall\n  fermions in free field theory at finite $L_s$: We find that the quark propagator constructed from the domain-wall fermion\noperator has $L_s-1$ extra poles as well as the pole that realizes the physical\nquark in the continuum limit. We show the energy-momentum dispersion relation\nfor the physical and unphysical poles of M\\\"obius domain-wall fermions in free\nfield theory at finite $L_s$. The dependence of extra pole energies on the\nM\\\"obius parameter $b-c$ and on the domain-wall height $M_5$ is investigated.\nOur result suggests that small values of $b-c$ set a large lower bound on the\nunphysical pole masses and the contribution of these poles could be suppressed\nwell by calculating with small $b-c$.",
        "positive": "QCD with Two Light Dynamical Chirally Improved Quarks: Results for the excited meson and baryon spectrum with two flavors of\nChirally Improved sea quarks are presented. We simulate several ensembles with\npion masses ranging from 250 to 600 MeV and extrapolate to the physical pion\nmass. Strange quarks are treated within the partially quenched approximation.\nUsing the variational method, we investigate the content of the states. Among\nothers, we discuss the flavor singlet/octet content of Lambda states. In\ngeneral, our results compare well with experiment, in particular we get very\ngood agreement with the Lambda(1405) and confirm its flavor singlet nature."
    },
    {
        "anchor": "Heavy Wilson Quarks and O($a$) Improvement: Nonperturbative Results for\n  $b_{\\rm g}$: With Wilson quarks, on-shell O($a$) improvement of the lattice QCD action is\nachieved by including the Sheikholeslami-Wohlert term and two further operators\nof mass dimension 5, which amount to a mass-dependent rescaling of the bare\nparameters. We here focus on the rescaled bare coupling, $\\tilde{g}_0^2 =\ng_0^2(1 + b_{\\rm g} am_{\\rm q})$, and the determination of $b_{\\rm g}(g_0^2)$,\nwhich is currently only known to 1-loop order of perturbation theory. We derive\nsuitable improvement conditions in the chiral limit and in a finite space-time\nvolume and evaluate these for different gluonic observables, both with and\nwithout the gradient flow. The choice of $\\beta$-values and the line of\nconstant physics are motivated by the ALPHA collaboration's decoupling strategy\nto determine $\\alpha_s(m_Z)$. However, the improvement conditions and some\ninsight into systematic effects may prove useful in other contexts, too.",
        "positive": "Second moment of the pion distribution amplitude with the momentum\n  smearing technique: Using the second moment of the pion distribution amplitude as an example, we\ninvestigate whether lattice calculations of matrix elements of local operators\ninvolving covariant derivatives may benefit from the recently proposed momentum\nsmearing technique for hadronic interpolators. Comparing the momentum smearing\ntechnique to the traditional Wuppertal smearing we find - at equal\ncomputational cost - a considerable reduction of the statistical errors. The\npresent investigation was carried out using $N_f=2+1$ dynamical\nnon-perturbatively order $a$ improved Wilson fermions on lattices of different\nvolumes and pion masses down to 220 MeV."
    },
    {
        "anchor": "A new simulation algorithm for lattice QCD with dynamical quarks: A previously introduced multi-boson technique for the simulation of QCD with\ndynamical quarks is described and some results of first test runs on a\n$6^3\\times12$ lattice with Wilson quarks and gauge group SU(2) are reported.",
        "positive": "Computation of the Running Coupling in the SU(2) Yang-Mills Theory: A finite-size scaling technique is applied to the SU(2) gauge theory (without\nmatter fields) to compute a non-perturbatively defined running coupling\nalpha(q) for a range of momenta q given in units of the string tension K. We\nfind that already at rather low q, the evolution of alpha(q) is well described\nby the 2-loop approximation to the Callan-Symanzik beta-function. At the\nhighest momentum reached, q=20 sqrt(K), we obtain alpha_MSbar(q)=0.187 +/-\n0.005 +/- 0.009 for the running coupling in the MSbar scheme of dimensional\nregularization."
    },
    {
        "anchor": "The coupled-channel scattering on a torus: Based on the Hamiltonian formalism approach, a generalized L\\\"uscher's\nformula for two particle scattering in both the elastic and coupled-channel\ncases in moving frames is derived from a relativistic Lippmann-Schwinger\nequation. Some strategies for extracting scattering amplitudes for a\ncoupled-channel system from the discrete finite-volume spectrum are discussed\nand illustrated with a toy model of two-channel resonant scattering. This\nformalism will, in the near future, be used to extract information about hadron\nscattering from lattice QCD computations.",
        "positive": "Common Structures in Simplicial Quantum Gravity: The statistical properties of dynamically triangulated manifolds (DT mfds) in\nterms of the geodesic distance have been studied numerically. The string\nsusceptibility exponents for the boundary surfaces in three-dimensional DT mfds\nwere measured numerically. For spherical boundary surfaces, we obtained a\nresult consistent with the case of a two-dimensional spherical DT surface\ndescribed by the matrix model. This gives a correct method to reconstruct\ntwo-dimensional random surfaces from three-dimensional DT mfds. Furthermore, a\nscaling property of the volume distribution of minimum neck baby universes was\ninvestigated numerically in the case of three and four dimensions, and we\nobtain a common scaling structure near to the critical points belonging to the\nstrong coupling phase in both dimensions. We have evidence for the existence of\na common fractal structure in three- and four-dimensional simplicial quantum\ngravity."
    },
    {
        "anchor": "Full $\\mathcal{O}(a)$ improvement of EQCD: EQCD is a 3D bosonic theory containing SU(3) and an adjoint scalar, which\nefficiently describes the infrared, nonperturbative sector of hot QCD and which\nis highly amenable to lattice study. We improve the matching between lattice\nand continuum EQCD by determining the final unknown coefficient in the\n$\\mathcal{O}(a)$ matching, an additive scalar mass renormalization. We do this\nnumerically by using the symmetry-breaking phase transition line of EQCD as a\nline of constant physics. This prepares the ground for a precision study of the\ntransverse momentum diffusion coefficient $C(q_\\perp)$ within this theory.",
        "positive": "Properties of light scalar mesons from lattice QCD: Lattice QCD with $N_f=2$ flavours of sea quark is used to explore the\nspectrum and decay of scalar mesons. We are able to determine the $b_1$ - $a_0$\nmass difference and this leads to the conclusion that the lightest non-singlet\nscalar meson ($a_0$) has a mass of 1.01(4) GeV. We determine from the lattice\nthe coupling strength to KK and $\\pi \\eta$. We compute the leptonic decay\nconstant of the lightest non-singlet scalar meson.\n  We discuss the impact of these lattice results on the interpretation of the\n$a_0(980)$ state. We also discuss $K^*_0$ states."
    },
    {
        "anchor": "QCD Spectroscopy: I review recent work on the calculation of hadron masses, decay constants and\nwave functions.",
        "positive": "$S$ parameter from a prototype composite-Higgs model: We have calculated the low-energy constant $L_{10}$ in a prototype composite\nHiggs model with dynamical fermions in two different representations of the\ngauge group. The resulting contribution of the new strong sector to the $S$\nparameter is consistent with current bounds on the vacuum misalignment\nparameter. We end with a brief discussion of future directions."
    },
    {
        "anchor": "Nucleon sigma term and strange quark content from lattice QCD with exact\n  chiral symmetry: We calculate the nucleon sigma term in two-flavor lattice QCD utilizing the\nFeynman-Hellman theorem. Both sea and valence quarks are described by the\noverlap fermion formulation, which preserves exact chiral and flavor symmetries\non the lattice. We analyse the lattice data for the nucleon mass using the\nanalytical formulae derived from the baryon chiral perturbation theory. From\nthe data at valence quark mass set different from sea quark mass, we may\nextract the sea quark contribution to the sigma term, which corresponds to the\nstrange quark content. We find that the strange quark content is much smaller\nthan the previous lattice calculations and phenomenological estimates.",
        "positive": "$\u039b_c-N$ interaction from lattice QCD: We investigate the s-wave $\\Lambda_c-N$ interaction for spin singlet\nsystems($^1S_0$) using the HAL QCD method. In our lattice QCD simulations, we\nemploy gauge configurations generated by the PACS-CS Collaboration at $a =\n0.0907(13)$ fm on a $32^3 \\times 64$ lattice ($La = 2.902(42)$ fm). We employ\ntwo ensembles, one at $m_\\pi = 700(1)$ MeV and the other at $m_\\pi = 570(1)$\nMeV to study the quark mass dependence of the $\\Lambda_c-N$ interactions. We\ncalculate a $^1S_0$ central potential not only for the $\\Lambda_c-N$ system but\nalso for $\\Lambda-N$ system to understand the role of heavy charm quarks in\n$\\Lambda_c-N$ system. We find repulsion at short distance and attraction at\nmid-range for both the $\\Lambda_c-N$ and the $\\Lambda-N$ potentials. The short\nrange repulsion of the $\\Lambda_c-N$ potential is smaller than that of the\n$\\Lambda-N$ potential, and the attraction of the $\\Lambda_c-N$ potential is\nsmall compared with the $\\Lambda-N$ potential. The phase shift and scattering\nlength calculated with these potentials show that there exist no bound state\nfor both the $\\Lambda_c-N$ and $\\Lambda-N$ systems for $m_{\\pi} > 570$ MeV."
    },
    {
        "anchor": "Green's Functions and Topological Configurations: There are, among others, currently two important views on the\nnon-perturbative structure of Yang-Mills theory. One is through topological\nconfigurations and one is through Green's functions, in particular their\n(asymptotic) infrared behavior. Based on both views, various scenarios for\nconfinement, chiral symmetry breaking and other non-perturbative effects have\nbeen developed. However, if both views are correct then they can only be\ndifferent aspects of the same underlying physics, and it must be possible to\nrelate them.\n  After discussing the current status of the understanding of this connection,\nsmeared and cooled configurations in lattice gauge theory are used to determine\nthe properties of Green's functions in the low-momentum regime. It is found\nthat the qualitative properties are essentially unchanged compared to results\non unsmeared configurations. This is also the case when the configurations are\nsmeared sufficiently strongly to reach the almost (anti-)self-dual domain.",
        "positive": "Kaon semileptonic decay form factors with HISQ valence quarks: We report on the status of our kaon semileptonic form factor calculations\nusing the highly-improved staggered quark (HISQ) formulation to simulate the\nvalence fermions. We present results for the form factor f_+^{K \\pi}(0) on the\nasqtad N_f=2+1 MILC configurations, discuss the chiral-continuum extrapolation,\nand give a preliminary estimate of the total error. We also present a more\npreliminary set of results for the same form factor but with the sea quarks\nalso simulated with the HISQ action; these results include data at the physical\nlight quark masses. The improvements that we expect to achieve with the use of\nthe HISQ configurations and simulations at the physical quark masses are\nbriefly discussed."
    },
    {
        "anchor": "Setting the scale for nHYP fermions with the L\u00fcscher-Weisz gauge\n  action: Lattice QCD calculations using gauge smearing for fermion kernels are\ncomputationally efficient. Hypercubic blocking (nHYP smearing) has been shown\nto reduce scaling errors. In this work we use an improved action for $N_f=2$\nQCD, based on the L\\\"uscher-Weisz gauge action and clover-improved Wilson\nfermions with nHYP smeared gauge links. We perform a parameter scan in the\nregion with lattice spacing between $0.066 \\mathop{\\hbox{fm}}$ and $0.115\n\\mathop{\\hbox{fm}}$ and pion mass between $207 \\mathop{\\hbox{MeV}}$ and $834\n\\mathop{\\hbox{MeV}}$.\n  We determine the lattice spacing and pion mass as a function of the bare\ncoupling parameters ($\\beta$ and $\\kappa$). The results are obtained from\ntwenty-two ensembles on a $24^3\\times 48$ lattice to percent level in\nstatistical accuracy. The finite-volume effects for these ensemble are at the\nsub-percent level. From these measurements we produce easy-to-use\nparameterizations to help tune simulations with this action. The lattice\nspacing is fixed using a mass-independent procedure, by matching observables in\nthe chiral limit. We also provide a parameterization for the chiral\nextrapolation which is universal and should hold for all discretizations of\n$N_f=2$ QCD.",
        "positive": "A strategy for the computation of m_b including 1/m terms: We consider HQET including the first order correction in 1/m. A strategy for\nthe computation of the b-quark mass is discussed. Only two quantities Phi_1/2\nhave to be considered in order to match QCD and HQET, since the spin-dependent\ninteraction is easily eliminated due to the spin symmetry of the static theory.\nQuite simple formulae relate the renormalization group invariant b-quark mass\n(M_b) to the B-meson mass. All entries in these formulae are non-perturbatively\ndefined and can be computed in the continuum limit of the lattice regularized\ntheory. For the numerically most critical part, we illustrate the cancellation\nof power divergences by a numerical example. Numerical results for the 1/m\ncorrection to M_b, are presented in a companion talk."
    },
    {
        "anchor": "Non-Perturbative Renormalization for Staggered Fermions (Self-energy\n  Analysis): We present preliminary results of data analysis for the non-perturbative\nrenormalization (NPR) on the self-energy of the quark propagators calculated\nusing HYP improved staggered fermions on the MILC asqtad lattices. We use the\nmomentum source to generate the quark propagators. In principle, using the\nvector projection operator of $(\\bar{\\bar{\\gamma_\\mu \\otimes 1}})$ and the\nscalar projection operator $(\\bar{\\bar{1 \\otimes 1}})$, we should be able to\nobtain the wave function renormalization factor $Z_q'$ and the mass\nrenormalization factor $Z_q \\cdot Z_m$. Using the MILC coarse lattice, we\nobtain a preliminary but reasonable estimate of $Z_q'$ and $Z_q \\cdot Z_m$ from\nthe data analysis on the self-energy.",
        "positive": "Adaptive Optimization of Wave Functions for Lattice Field Models: The accuracy of Green Function Monte Carlo (GFMC) simulations can be greatly\nimproved by a clever choice of the approximate ground state wave function that\ncontrols configuration sampling. This trial wave function typically depends on\nmany free parameters whose fixing is a non trivial task. Here, we discuss a\ngeneral purpose adaptive algorithm for their non-linear optimization. As a non\ntrivial application we test the method on the two dimensional Wess-Zumino\nmodel, a relativistically invariant supersymmetric field theory with\ninteracting bosonic and fermionic degrees of freedom."
    },
    {
        "anchor": "The non-perturbative O(a)-improved action for dynamical Wilson fermions: We compute the improvement coefficient $c_{sw}$ that multiplies the\nSheikholeslami-Wohlert term as a function of the bare gauge coupling for two\nflavour QCD. We discuss several aspects concerning simulations with improved\ndynamical Wilson fermions.",
        "positive": "Flow-based sampling in the lattice Schwinger model at criticality: Recent results suggest that flow-based algorithms may provide efficient\nsampling of field distributions for lattice field theory applications, such as\nstudies of quantum chromodynamics and the Schwinger model. In this work, we\nprovide a numerical demonstration of robust flow-based sampling in the\nSchwinger model at the critical value of the fermion mass. In contrast, at the\nsame parameters, conventional methods fail to sample all parts of configuration\nspace, leading to severely underestimated uncertainties."
    },
    {
        "anchor": "Study of three-flavored heavy dibaryons using lattice QCD: We present results of the first lattice QCD calculation of three-flavored\nheavy dibaryons both in the flavor-symmetric and antisymmetric channels. These\ndibaryons have spin zero, and are constructed using various possible\ncombinations of quark flavors with at least one of them as the charm or the\nbottom quark, i.e., namely, $H_c(cudcud), H_b(budbud), H_{bcs}(bcsbcs)$,\n$H_{csl}(cslcsl), H_{bsl}(bslbsl)$ and $H_{bcl}(bclbcl)$; $l\\in u,d$. We\ncompute the ground state masses of these dibaryons and the calculations are\nperformed on three $N_f=2+1+1$ HISQ gauge ensembles of the MILC collaboration,\nwith lattice spacings $a =$ 0.1207, 0.0888 and 0.0582 fm. A relativistic\noverlap action is employed for the valence light to charm quarks while a\nnon-relativistic-QCD Hamiltonian with improved coefficients is used for the\nbottom quarks. Unlike the doubly heavy tetraquarks, one and two-flavored heavy\ndibaryons, for which lattice QCD calculations have predicted deeply bound\nstrong-interactions-stable states, for these $H_c, H_b, H_{csl},H_{bsl}$\ndibaryons we do not find any such deeply bound state. However, for $H_{bcs}$,\nour results indicate the presence of an energy level $29\\pm 24$ MeV below the\nlowest two-baryon threshold, which could be relevant for its future\nexperimental searches. Moreover, we find that the energy difference between the\nground state of $H_{bcl}$ and its lowest threshold increases when $m_l>m_s$.\nTaken together, our findings indicate the possibility of the existence of the\n$H_{bcs}$ dibaryon while all other physical three-flavored dibaryons are much\ncloser to their thresholds suggesting either they are weakly bound or unbound,\nresolving which requires further detail study. Our results also point that the\nbinding of a dibaryon configuration becomes stronger with the increase of its\nvalence quark masses which suggests an interesting aspect of strong\ninteractions at multiple scales.",
        "positive": "Spectroscopy of four-dimensional $\\mathcal{N}=1$ supersymmetric SU(3)\n  Yang-Mills theory: Supersymmetric gauge theories are an important building block for extensions\nof the standard model. As a first step towards Super-QCD we investigate the\npure gauge sector with gluons and gluinos on the lattice, in particular the low\nenergy mass spectrum: meson-like gluinoballs, gluino-glueballs and pure\nglueballs. We report on some first calculations performed with clover improved\nWilson fermions on rather small lattices. The supersymmetric continuum limit\nand particle masses are discussed and compared to predictions from effective\nfield theory."
    },
    {
        "anchor": "Anisotropic Improved Gauge Actions; --Perturbative and Numerical Studies\n  --: The $\\Lambda$ parameter on the anisotropic lattice, the spatial and\ntemperature coupling constant $g_{\\sigma}$, $g_{\\tau}$ and their derivative\nwith respaect to the the anisotropy parameter $\\xi$ are studied perturbatively\nfor the class of improved actions, which cover tree level Symanzik's, Iwasaki's\nand QCDTARO's improved actions. The $\\eta(=g_{\\tau}/g_{\\sigma})$ becomes less\nthan 1 for Iwasaki's and QCDTARO's action, which is confirmed nonperturbatively\nby numerical simulations. Derivatives of the coupling constants with respect to\nthe anisotropy parameter, $\\partial g_{\\tau}/\\partial \\xi$ and $\\partial\ng_{\\sigma}/\\partial \\xi$, change sign for those improved actions.",
        "positive": "Evidence for Dyonic Structure of SU(2) Lattice Gauge Fields Below $T_c$: We report the observation of calorons with nontrivial holonomy and fractional\ntopological charge objects in cooled lattice samples derived from SU(2)\nequilibrium ensembles at $T<T_c$."
    },
    {
        "anchor": "Hadron Spectrum in QCD with Valence Wilson Fermions and Dynamical\n  Staggered Fermions at $6/g^2=5.6: We present an analysis of hadronic spectroscopy for Wilson valence quarks\nwith dynamical staggered fermions at lattice coupling $6/g^2 = \\beta=5.6$ at\nsea quark mass $am_q=0.01$ and 0.025, and of Wilson valence quarks in quenched\napproximation at $\\beta=5.85$ and 5.95, both on $16^3 \\times 32$ lattices. We\nmake comparisons with our previous results with dynamical staggered fermions at\nthe same parameter values but on $16^4$ lattices doubled in the temporal\ndirection.",
        "positive": "Improvement, dynamical fermions, and heavy quark screening in QCD_3: First results from simulations of improved actions for both gauge fields and\nstaggered fermion fields in three dimensional QCD are presented. This work\nprovides insight into some issues of relevance to lattice theories in four\ndimensions. In particular, the renormalization of the bare lattice coupling is\ndramatically reduced when the tree-level $O(a^2)$ improved action is used. Naik\nimprovement of the staggered fermion action produces little reduction in\nscaling violations of the rho meson mass. String breaking in the heavy quark\npotential in the unquenched theory is also clearly resolved, using Wilson loops\nto bound the ground state energy."
    },
    {
        "anchor": "Recent lattice QCD results and phase diagram of strongly interacting\n  matter: I review recent lattice QCD results on a few selected topics which are\nrelevant to the heavy ion physics community. Special emphasis is put on the QCD\nequation of state at vanishing and nonzero baryon chemical potential, the onset\nof deconfinement of open strange and charmed hadrons, the contribution from\nexperimentally not yet observed hadrons to the thermodynamics of the hadronic\ngas and their influence on freeze-out conditions of strange and light-quark\nhadrons.",
        "positive": "A Strategy to Study Confinement in QCD: The order and the universality class of the deconfining phase transition can\nprovide insight into the mechanism of color confinement, in particular for\nN_f=2. The mechanism of confinement by monopole condensation is reviewed."
    },
    {
        "anchor": "Gravitational form factors of the pion from lattice QCD: The two gravitational form factors of the pion, $A^{\\pi}(t)$ and\n$D^{\\pi}(t)$, are computed as functions of the momentum transfer squared $t$ in\nthe kinematic region $0\\leq -t< 2~\\text{GeV}^2$ on a lattice QCD ensemble with\nquark masses corresponding to a close-to-physical pion mass $m_{\\pi}\\approx\n170~\\text{MeV}$ and $N_f=2+1$ quark flavors. The flavor decomposition of these\nform factors into gluon, up/down light-quark, and strange-quark contributions\nis presented in the $\\overline{\\text{MS}}$ scheme at energy scale\n$\\mu=2~\\text{GeV}$, with renormalization factors computed nonperturbatively via\nthe RI-MOM scheme. Using monopole and $z$-expansion fits to the gravitational\nform factors, we obtain estimates for the pion momentum fraction and $D$-term\nthat are consistent with the momentum fraction sum rule and the next-to-leading\norder chiral perturbation theory prediction for $D^{\\pi}(0)$.",
        "positive": "Lattice perturbation theory for gluonic and fermionic actions: We calculate the two loop Landau mean links and the one loop renormalisation\nof the anisotropy for Wilson and improved SU(3) gauge actions, using twisted\nboundary conditions as a gauge invariant infrared regulator. We show these\naccurately describe simulated results, and outline a method for generating\nFeynman rules for general lattice field theories, in a form suitable for\nefficient numerical calculation of perturbative loop diagrams."
    },
    {
        "anchor": "Towards the lattice study of M-theory (II): We present new results of the quenched simulations of the reduced D=4\nsupersymmetric Yang - Mills quantum mechanics for larger gauge groups SU(N),\n2<N<9. The model, studied at finite temperature, reveals existence of the two\ndistinct regions which may be precursors of a black hole and the elementary D0\nbranes phases of M-theory conjectured in the literature. Present results for\nhigher groups confirm the picture found already for N=2. Similar behaviour is\nobserved in the preliminary simulations for the D=6 and D=10 models.",
        "positive": "Hadronic contribution to g-2 from twisted mass fermions: We calculate the vacuum polarization tensor for pion masses from 480 MeV to\n270 MeV using dynamical twisted mass fermions at a lattice spacing of 0.086 fm.\nWe analyze the form of the polarization tensor on the lattice using the\nsymmetries of twisted QCD and we study both finite size effects and lattice\nartifacts at a pion mass of 310 MeV. Results for the lowest order hadronic\ncontribution to g-2 are presented and the impact of systematic errors is\ndiscussed."
    },
    {
        "anchor": "Diagonal and off-diagonal quark number susceptibilities at high\n  temperatures: We present continuum extrapolated lattice QCD results for up to fourth-order\ndiagonal and off-diagonal quark number susceptibilities in the high temperature\nregion of 300-700 MeV. Lattice QCD calculations are performed using 2+1 flavors\nof highly improved staggered quarks with nearly physical quark masses and at\nfour different lattice spacings. Comparisons of our results with recent weak\ncoupling perturbative calculations yield reasonably good agreements for the\nentire temperature range.",
        "positive": "Up, down, strange and charm quark masses with Nf = 2+1+1 twisted mass\n  lattice QCD: We present a lattice QCD calculation of the up, down, strange and charm quark\nmasses performed using the gauge configurations produced by the European\nTwisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include\nin the sea, besides two light mass degenerate quarks, also the strange and\ncharm quarks with masses close to their physical values. The simulations are\nbased on a unitary setup for the two light quarks and on a mixed action\napproach for the strange and charm quarks. The analysis uses data at three\nvalues of the lattice spacing and pion masses in the range 210 - 450 MeV,\nallowing for accurate continuum limit and controlled chiral extrapolation. The\nquark mass renormalization is carried out non-perturbatively using the RI-MOM\nmethod. The results for the quark masses converted to the bar{MS} scheme are:\nmud(2 GeV) = 3.70(17) MeV, ms(2 GeV) = 99.6(4.3) MeV and mc(mc) = 1.348(46)\nGeV. We obtain also the quark mass ratios ms/mud = 26.66(32) and mc/ms =\n11.62(16). By studying the mass splitting between the neutral and charged kaons\nand using available lattice results for the electromagnetic contributions, we\nevaluate mu/md = 0.470(56), leading to mu = 2.36(24) MeV and md = 5.03(26) MeV."
    },
    {
        "anchor": "Nuclear effective field theory on the lattice: In the low-energy region far below the chiral symmetry breaking scale (which\nis of the order of 1 GeV) chiral perturbation theory provides a\nmodel-independent approach for quantitative description of nuclear processes.\nIn the two- and more-nucleon sector perturbation theory is applicable only at\nthe level of an effective potential which serves as input in the corresponding\ndynamical equation. To deal with the resulting many-body problem we put chiral\neffective field theory (EFT) on the lattice. Here we present the results of our\nlattice EFT study up to next-to-next-to-leading order in the chiral expansion.\nAccurate description of two-nucleon phase-shifts and ground state energy ratio\nof dilute neutron matter up to corrections of higher orders shows that lattice\nEFT is a promising tool for a quantitative description of low-energy few- and\nmany-body systems.",
        "positive": "Spectral reconstruction details of a gradient-flowed color-electric\n  correlator: In a recently published work we provide a proof-of-concept of a novel method\nto extract the heavy quark momentum diffusion coefficient from color-electric\ncorrelators on the lattice using gradient flow. The transport coefficient can\nbe found in the infrared limit of the corresponding spectral function which is\nreconstructed through perturbative model fits of the correlator data. In this\nproceedings report we want to give more detailed insights into the systematic\nuncertainties of this procedure and compare our results with other studies."
    },
    {
        "anchor": "Non-Perturbative Evaluation of the Physical Classical Velocity in the\n  Lattice Heavy Quark Effective Theory: In the lattice formulation of the Heavy Quark Effective Theory, the value of\nthe classical velocity v, as defined through the separation of the 4-momentum\nof a heavy quark into a part proportional to the heavy quark mass and a\nresidual part which remains finite in the heavy quark limit (P = Mv + p) is\ndifferent from its value as it appears in the bare heavy quark propagator (S(p)\n= 1/vp). The origin of the difference, which is effectively a lattice-induced\nrenormalization, is the reduction of Lorentz (or O(4)) invariance to\n(hyper)-cubic invariance. The renormalization is finite and depends\nspecifically on the form of the discretization of the reduced heavy quark Dirac\nequation. For the Forward Time - Centered Space discretization, we compute this\nrenormalization non-perturbatively, using an ensemble of lattices at beta = 6.1\nprovided by the Fermilab ACP-MAPS Collaboration. The calculation makes crucial\nuse of a variationally optimized smeared operator for creating composite\nheavy-light mesons. It has the property that its propagator achieves an\nasymptotic plateau in just a few Euclidean time steps. For comparison, we also\ncompute the shift perturbatively, to one loop in lattice perturbation theory.\nThe non-perturbative calculation of the leading multiplicative shift in the\nclassical velocity is considerably different from the one-loop estimate, and\nindicates that for the above parameters, v is reduced by about 10-13%.",
        "positive": "Center vortices on SU(2) lattices: We show that gauge invariant definition of thin, thick and hybrid center\nvortices, defined by Kovacs and Tomboulis on SO(3) x Z(2) configurations, can\nalso be defined in SU(2). We make this connection using the freedom of choosing\na particular SU(2) representative of SO(3). We further show that in another\nrepresentative the Tomboulis \\sigma - \\eta thin vortices are P (projection)\nvortices. The projection approximation corresponds to dropping the perimeter\nfactor of a Wilson loop after appropriate gauge fixing. We present results for\nstatic quark potentials based on these vortex counters and compare pojection\nvortex counters with gauge invariant ones on the same configuration."
    },
    {
        "anchor": "Lattice Gluon and Ghost Propagators, and the Strong Coupling in Pure\n  SU(3) Yang-Mills Theory: Finite Lattice Spacing and Volume Effects: The dependence of the Landau gauge two point gluon and ghost correlation\nfunctions on the lattice spacing and on the physical volume are investigated\nfor pure SU(3) Yang-Mills theory in four dimensions using lattice simulations.\nWe present data from very large lattices up to $128^4$ and for two lattice\nspacings $0.10$ fm and $0.06$ fm corresponding to volumes of $\\sim$ (13 fm)$^4$\nand $\\sim$ (8 fm)$^4$, respectively. Our results show that, for sufficiently\nlarge physical volumes, both propagators have a mild dependence on the lattice\nvolume. On the other hand, the gluon and ghost propagators change with the\nlattice spacing $a$ in the infrared region, with the gluon propagator having a\nstronger dependence on $a$ compared to the ghost propagator. In what concerns\nthe strong coupling constant $\\alpha_s (p^2)$, as defined from gluon and ghost\ntwo point functions, the simulations show a sizeable dependence on the lattice\nspacing for the infrared region and for momenta up to $\\sim 1$ GeV.",
        "positive": "Relativistic three-particle quantization condition for nondegenerate\n  scalars: The formalism relating the relativistic three-particle infinite-volume\nscattering amplitude to the finite-volume spectrum has been developed thus far\nonly for identical or degenerate particles. We provide the generalization to\nthe case of three nondegenerate scalar particles with arbitrary masses. A key\nquantity in this formalism is the quantization condition, which relates the\nspectrum to an intermediate K matrix. We derive three versions of this\nquantization condition, each a natural generalization of the corresponding\nresults for identical particles. In each case we also determine the integral\nequations relating the intermediate K matrix to the three-particle scattering\namplitude, $\\mathcal M_3$. The version that is likely to be most practical\ninvolves a single Lorentz-invariant intermediate K matrix, $\\widetilde{\\mathcal\nK}_{\\rm df,3}$. The other versions involve a matrix of K matrices, with\nelements distinguished by the choice of which initial and final particles are\nthe spectators. Our approach should allow a straightforward generalization of\nthe relativistic approach to all other three-particle systems of interest."
    },
    {
        "anchor": "Inhomogeneous phases in the 3+1-dimensional Nambu-Jona-Lasinio model and\n  their dependence on the regularization scheme: In this work we study the $3+1$-dimensional Nambu-Jona-Lasinio (NJL) model in\nthe mean field-approximation. We carry out calculations using five different\nregularization schemes (two continuum and three lattice regularization schemes)\nwith particular focus on inhomogeneous phases and condensates. The\nregularization schemes lead to drastically different inhomogeneous regions. We\nprovide evidence that inhomogeneous condensates appear for all regularization\nschemes almost exclusively at values of the chemical potential and with wave\nnumbers, which are of the order of or even larger than the corresponding\nregulators. This can be interpreted as indication that inhomogeneous phases in\nthe $3+1$-dimensional NJL model are rather artifacts of the regularization and\nnot a consequence of the NJL Lagrangian and its symmetries.",
        "positive": "Light Quark Physics on Different Lattices: The light quark results from three different simulations are summarized. We\nget consistent results, within our statistics, between smeared and non smeared\ndata. A comparison is performed with similar results from the UKQCD\ncollaboration. All runs have been performed on two 6.4 GF APE computers\n\\cite{tubo}."
    },
    {
        "anchor": "Nucleon structure from RBC/UKQCD 2+1 flavor DWF dynamical ensembles at a\n  nearly physical pion mass: We report the status of nucleon structure calculations on the (2+1)-flavor\ndynamical domain-wall fermions ensembles with pion masses as low as 180 and 250\nMeV on a lattice with about 4.6 fm spatial extent. A combination of the\nIwasaki+dislocation- suppressing-determinant-ratio (I+DSDR) gauge action and\nDWF fermion action allows us to generate these ensembles at cutoff of about 1.4\nGeV while keeping the residual mass small. Nucleon source Gaussian smearing has\nbeen optimized. Preliminary nucleon mass estimates are 0.98 and 1.05 GeV.",
        "positive": "R-symmetry in the Q-exact (2,2) 2d lattice Wess-Zumino model: In this article we explore the R-symmetry of the (2,2) 2d Wess-Zumino model.\nWe study whether or not this symmetry is approximately realized in the Q-exact\nlattice version of this theory. Our study is nonperturbative: it relies on\nMonte Carlo simulations with dynamical fermions. Irrelevant operators in the\nlattice action explicitly break the R-symmetry. In spite of this, it is found\nto be a symmetry of the effective potential. We find nonperturbative evidence\nthat the nonrenormalization theorem of the continuum theory is recovered in the\ncontinuum limit; e.g., there is no additive mass renormalization. In our\nsimulations we find that Fourier acceleration of the hybrid Monte Carlo\nalgorithm allows us to avoid difficulties with critical slowing-down."
    },
    {
        "anchor": "The role of boundary conditions in quantum computations of scattering\n  observables: Quantum computing may offer the opportunity to simulate strongly-interacting\nfield theories, such as quantum chromodynamics, with physical time evolution.\nThis would give access to Minkowski-signature correlators, in contrast to the\nEuclidean calculations routinely performed at present. However, as with\npresent-day calculations, quantum computation strategies still require the\nrestriction to a finite system size, including a finite, usually periodic,\nspatial volume. In this work, we investigate the consequences of this in the\nextraction of hadronic and Compton-like scattering amplitudes. Using the\nframework presented in Phys. Rev. D101 014509 (2020), we quantify the volume\neffects for various $1+1$D Minkowski-signature quantities and show that these\ncan be a significant source of systematic uncertainty, even for volumes that\nare very large by the standards of present-day Euclidean calculations. We then\npresent an improvement strategy, based in the fact that the finite volume has a\nreduced symmetry. This implies that kinematic points, which yield the same\nLorentz invariants, may still be physically distinct in the finite-volume\nsystem. As we demonstrate, both numerically and analytically, averaging over\nsuch sets can significantly suppress the unwanted volume distortions and\nimprove the extraction of the physical scattering amplitudes.",
        "positive": "Finite Lattice Hamiltonian Computations in the P-Representation: the\n  Schwinger Model: The Schwinger model is studied in a finite lattice by means of the\nP-representation. The vacuum energy, mass gap and chiral condensate are\nevaluated showing good agreement with the expected values in the continuum\nlimit."
    },
    {
        "anchor": "Two-loop renormalization of vector, axial-vector and tensor fermion\n  bilinears on the lattice: We compute the two-loop renormalization functions, in the RI' scheme, of\nlocal bilinear quark operators $\\bar{\\psi}\\Gamma\\psi$, where $\\Gamma$\ncorresponds to the Vector, Axial-Vector and Tensor Dirac operators, in the\nlattice formulation of QCD. We consider both the flavor nonsinglet and singlet\noperators.\n  We use the clover action for fermions and the Wilson action for gluons. Our\nresults are given as a polynomial in $c_{SW}$, in terms of both the\nrenormalized and bare coupling constant, in the renormalized Feynman gauge.\n  Finally, we present our results in the MSbar scheme, for easier comparison\nwith calculations in the continuum. The corresponding results, for fermions in\nan arbitrary representation, together with some special features of\nsuperficially divergent integrals, are included in the Appendices.",
        "positive": "Meson interactions at large $N_c$ from Lattice QCD: We report on the computation of the scaling of QCD observables with the\nnumber of colours, $N_c$. For this, we use dynamical configurations with four\nactive flavours, $N_f=4$, and values of $N_c=3-6$. We study the meson masses\nand decay constants, and compute the leading and subleading contributions to\nthe Low Energy Constants (LECs) of the chiral Lagrangian. We also explore $\\pi\n\\pi$ scattering in the $I=2$ channel, and compute the $K \\to \\pi $ weak decay\nmatrix elements. We comment on the relation of the latter to $K \\to \\pi\\pi$\nprocesses and the $\\Delta I=1/2$ rule."
    },
    {
        "anchor": "Trivializing Flow in 2D O(3) sigma model: The two dimensional O(3) sigma model, just as quantum chromodynamics, is an\nasymptotically free theory with a mass gap. Therefore, it is an interesting and\nsimple toy model to investigate algorithms for Markov Chain Monte Carlo\nsimulations of quantum chromodynamics. In this talk, we discuss the\nconstruction of a trivializing map, a field transformation from a given theory\nto a trivial one, through a suitably chosen gradient flow. An analytic solution\nfor the generating functional of this trivializing flow has been obtained by a\nperturbative expansion in the flow time. Utilizing this solution allows for new\napproaches to be considered when proposing updates for a Markov Chain Monte\nCarlo algorithm.",
        "positive": "Light quark masses from unquenched lattice QCD: We calculate the light meson spectrum and the light quark masses by lattice\nQCD simulation, treating all light quarks dynamically and employing the Iwasaki\ngluon action and the nonperturbatively O(a)-improved Wilson quark action. The\ncalculations are made at the squared lattice spacings at an equal distance\na^2~0.005, 0.01 and 0.015 fm^2, and the continuum limit is taken assuming an\nO(a^2) discretization error. The light meson spectrum is consistent with\nexperiment. The up, down and strange quark masses in the \\bar{MS} scheme at 2\nGeV are \\bar{m}=(m_{u}+m_{d})/2=3.55^{+0.65}_{-0.28} MeV and\nm_s=90.1^{+17.2}_{-6.1} MeV where the error includes statistical and all\nsystematic errors added in quadrature. These values contain the previous\nestimates obtained with the dynamical u and d quarks within the error."
    },
    {
        "anchor": "Exploring twisted mass Lattice QCD with the Clover term: It has been shown that in the twisted mass formulation of Lattice QCD at\nmaximal twist large cutoff effects are generated when the quark mass becomes of\nO(a Lambda_QCD^2). In general, these effects can be suppressed in two ways:\neither by choosing the critical quark mass in an \"optimal way\", or by adding\nthe Clover term to the twisted action. We investigate the second option by\nperforming a quenched lattice QCD simulation with twisted Clover fermions and\npion masses as low as 280 MeV. We show that the Clover term is indeed efficient\nin reducing the large cutoff effects. In particular, the so-called bending\nphenomenon observed in the determination of the pion decay constant is cured in\nthis way. In addition, by using maximally twisted Clover fermions, we provide a\nnon-perturbative determination of the vector current renormalization constant\nZ_V as well as of the non-perturbatively renormalized light quark masses.\nFinally, we calculate the connected contribution to the charged-neutral\npseudoscalar meson mass splitting, finding that the introduction of the Clover\nterm in the twisted action is also beneficial, in the quenched approximation,\nin reducing cutoff effects related to the isospin symmetry breaking at finite\nlattice spacing.",
        "positive": "Nucleon form factors from $N_f$=2+1+1 twisted mass QCD at the physical\n  point: We present the nucleon axial and electromagnetic form factors using\n\\Nf{2}{1}{1} ensembles of twisted mass fermions with clover improvement and\nwith masses tuned to their physical values. Excited state effects are studied\nusing several sink-source time separations in the range 0.8 fm - 1.6 fm,\nexponentially increasing statistics with the separation such that statistical\nerrors remain approximately constant. In addition, quark loop disconnected\ndiagrams are included in order to extract the isoscalar axial form factors and\nthe proton and neutron electromagnetic form factors, as well as their\nstrange-quark contributions. The radii and moments are extracted by modelling\nthe $Q^2$ dependence, including using the so-called $z$-expansion. A\npreliminary assessment of lattice cut-off effects is presented using two\nlattice spacings directly at the physical point."
    },
    {
        "anchor": "Viscosities of Hot Gluon -- A Lattice QCD Study --: We present transport coefficients (shear viscosity, $\\eta$, and bulk\nviscosity, $\\zeta$) for the gluon system obtained by the lattice QCD. This is\nan indispensable calculation towards the understanding of ``New State of\nMatter'' observed in RHIC. We study the temperature regions of RHIC ($1.4 \\leq\nT/T_c \\leq 1.8$) and much higher ones up to $ T/T_c \\sim 20$. In RHIC regions,\nthe ratio of shear viscosity to entropy density, $\\eta/s$, is around $\\sim\n0.1-0.4$, and satisfies the KSS bound. At high temperature, $\\eta$ becomes two\nor three oder of magnitude larger. Our calculation has two limitations: (i) the\nuse of the quench approximation, i.e., without quark pair creation-annihilation\neffects on vacuum, and (ii) the use of an ansatz for the spectral function. The\nfirst point has been well studied in calculations of the spectroscopy and the\nphase-transition behavior. To investigate the second point, we compare our\nresults with perturbative calculations in high $T$-regions, and also check the\neffects of the modification of the spectral function on the viscosity.",
        "positive": "Lattice artefacts and the running of the coupling constant: We study the running of the L\\\"uscher-Weisz-Wolff (LWW) coupling constant in\nthe two dimensional O(3) nonlinear $\\sigma$ model. To investigate the continuum\nlimit we refine the lattice spacing from the $1\\over 16$ value used by LWW up\nto $1\\over 160$. We find that the lattice artefacts are much larger than\nestimated by LWW and that most likely the coupling constant runs slower than\npredicted by perturbation theory. A precise determination of the running in the\ncontinuum limit would require a controlled ansatz of extrapolation, which, we\nargue, is not presently available."
    },
    {
        "anchor": "Implementing the three-particle quantization condition for\n  $\u03c0^+\u03c0^+K^+$ and related systems: Recently, the formalism needed to relate the finite-volume spectrum of\nsystems of nondegenerate spinless particles has been derived. In this work we\ndiscuss a range of issues that arise when implementing this formalism in\npractice, provide further theoretical results that can be used to check the\nimplementation, and make available codes for implementing the three-particle\nquantization condition. Specifically, we discuss the need to modify the upper\nlimit of the cutoff function due to the fact that the left-hand cut in the\nscattering amplitudes for two nondegenerate particles moves closer to\nthreshold; we describe the decomposition of the three-particle amplitude\n$\\mathcal{K}_\\text{df,3}$ into the matrix basis used in the quantization\ncondition, including both $s$ and $p$ waves, with the latter arising in the\namplitude for two nondegenerate particles; we derive the threshold expansion\nfor the lightest three-particle state in the rest frame up to\n$\\mathcal{O}(1/L^5)$; and we calculate the leading-order predictions in chiral\nperturbation theory for $\\mathcal{K}_\\text{df,3}$ in the $\\pi^+\\pi^+K^+$ and\n$\\pi^+K^+K^+$ systems. We focus mainly on systems with two identical particles\nplus a third that is different (\"2+1\" systems). We describe the formalism in\nfull detail, and present numerical explorations in toy models, in particular\nchecking that the results agree with the threshold expansion, and making a\nprediction for the spectrum of $\\pi^+\\pi^+K^+$ levels using the two- and\nthree-particle interactions predicted by chiral perturbation theory.",
        "positive": "Dirac eigenvalue correlations in quenched QCD at finite density: We compare eigenvalue correlations of the Dirac operator with a chemical\npotential obtained from lattice simulations of quenched QCD with analytic\npredictions obtained from chiral effective theories in the zero-momentum limit.\nBy comparing the density and two-point correlation function we show that the\nanalytic results agree with QCD at low energies. We also examine the scale\n(Thouless energy) up to which the zero-momentum approximation is valid."
    },
    {
        "anchor": "Simulating the All-Order Strong Coupling Expansion IV: CP(N-1) as a loop\n  model: We exactly reformulate the lattice CP(N-1) spin model on a D dimensional\ntorus as a loop model whose configurations correspond to the complete set of\nstrong coupling graphs of the original system. A Monte Carlo algorithm is\ndescribed and tested that samples the loop model with its configurations stored\nand manipulated as a linked list. Complete absence of critical slowing down and\ncorrespondingly small errors are found at D=2 for several observables including\nthe mass gap. Using two different standard lattice actions universality is\ndemonstrated in a finite size scaling study. The topological charge is\nidentified in the loop model but not yet investigated numerically.",
        "positive": "Hamiltonian Lattice QCD from Strong Coupling Expansion: We present generalizations of Hamiltonian Lattice QCD as derived from the\ncontinuous time limit of strong coupling lattice QCD: we discuss the flavor\ndependence and the effect of gauge corrections. This formalism can be applied\nat finite temperature and baryon density as well as isospin density and allows\nboth for analytic and numeric investigations that are sign problem-free."
    },
    {
        "anchor": "Bootstrapping Lattice Vacua: This paper demonstrates the application of semidefinite programming to\nlattice field theories, showcasing spin chains and lattice scalar field theory.\nRequiring expectation values of manifestly positive semi-definite operators to\nbe non-negative results in a lower bound on the ground-state energy of any\nquantum mechanical system, which can be made arbitrarily tight for systems\ndescribed by finite-dimensional Hilbert spaces. Such bounds can be obtained\ndirectly in the infinite-volume limit. The process of optimizing these lower\nbounds also yields estimates for a chosen set of expectation values in the\nground state.",
        "positive": "Remarks on the multi-parameter reweighting method for the study of\n  lattice QCD at non-zero temperature and density: We comment on the reweighting method for the study of finite density lattice\nQCD. We discuss the applicable parameter range of the reweighting method for\nmodels which have more than one simulation parameter. The applicability range\nis determined by the fluctuations of the modification factor of the Boltzmann\nweight. In some models having a first order phase transition, the fluctuations\nare minimized along the phase transition line if we assume that the pressure in\nthe hot and the cold phase is balanced at the first order phase transition\npoint. This suggests that the reweighting method with two parameters is\napplicable in a wide range for the purpose of tracing out the phase transition\nline in the parameter space. To confirm the usefulness of the reweighting\nmethod for 2 flavor QCD, the fluctuations of the reweighting factor are\nmeasured by numerical simulations for the cases of reweighting in the quark\nmass and chemical potential directions. The relation with the phase transition\nline is discussed. Moreover, the sign problem caused by the complex phase\nfluctuations is studied."
    },
    {
        "anchor": "QCD on Rotating Lattice with Staggered Fermions: We investigate the finite-temperature quantum chromodynamics (QCD) on a\nrotating lattice with $N_f=2+1$ staggered fermions and the projective plane\nboundary condition. We observe a negative rotational rigidity (defined in the\nmain text) and a negative quark spin susceptibility associated with the chiral\nvortical effect. In contrast to most of the effective model predictions, we\nfind that the chiral condensate decreases and the Polyakov loop increases with\nimaginary rotation, implying a rotational catalysis of chiral symmetry breaking\nand confinement by real rotation. We determine the phase boundaries for both\nchiral and confinement-deconfinement phase transitions on the $\\Omega_I$-$T$\nplane, where $\\Omega_I$ is the imaginary angular velocity.",
        "positive": "Strange quark content of the nucleon and dark matter searches: The strange quark scalar content plays an important role in both the\ndescription of nucleon structure and in the determination of dark matter direct\ndetection cross sections. As a measure of the strange-quark contribution to the\nnucleon mass, the strange-quark sigma term (\\sigma_s) provides important\ninsight into the nature of mass generation in QCD. The phenomenological\ndetermination of \\sigma_s exhibits a wide range of variation, with values\nsuggesting that the strange quark contributes anywhere between 0 and more than\n30% of the nucleon mass. In the context of dark matter searches, coupled with\nrelatively large Higgs coupling to strangeness, this variation dominates the\nuncertainty in predicted cross sections for a large class of dark matter\nmodels. Here we report on the recent results in lattice QCD, which are now\ngiving a far more precise determination of \\sigma_s than can be inferred from\nphenomenology. As a consequence, the lattice determinations of \\sigma_s can now\ndramatically reduce the uncertainty in dark matter cross sections associated\nwith the hadronic matrix elements."
    },
    {
        "anchor": "Observables of Lattice Gauge Theory in Minkowski Space: U(1) gauge fields are decomposed into a monopole and photon part across the\nphase transition from the confinement to the Coulomb phase. We analyze the\nleading Lyapunov exponents of such gauge field configurations on the lattice\nwhich are initialized by quantum Monte Carlo simulations. We observe that the\nmonopole field carries the same Lyapunov exponent as the original U(1) field.\nEvidence is found that monopole fields stay chaotic in the continuum whereas\nthe photon fields are regular. First results are presented for the full\nspectrum of Lyapunov exponents of the U(1) gauge system.",
        "positive": "Width of Long Colour Flux Tubes in Lattice Gauge Systems: In the confining phase of any gauge system the mean squared width of the\ncolour flux tube joining a pair of quarks should grow logarithmically as a\nfunction of their distance, according to the effective string description of\nits infrared properties. New data on 3D Z_2 gauge theory, combined with high\nprecision data on the interface physics of the 3D Ising model fit nicely this\nbehaviour over a range of more than two orders of magnitude."
    },
    {
        "anchor": "Direct lattice calculation of inclusive hadronic decay rates of the\n  $\u03c4$ lepton: The inclusive hadronic decay-rates of the $\\tau$ lepton are particularly\ninteresting from the phenomenological point of view since they give access to\nthe CKM matrix elements $V_{ud}$ and $V_{us}$. In this talk, we discuss how a\nrecent method for the extraction of smeared spectral densities from Euclidean\nlattice correlators can be used to obtain a direct lattice determination of\ninclusive hadronic $\\tau$ decay rates. We also present preliminary numerical\nresults obtained by applying this method to correlators measured on two gauge\nensembles produced by the ETMC with $N_f=2+1+1$ dynamical flavours at physical\npion masses, lattice spacing $a\\simeq 0.08$ fm and volumes $L\\simeq 5.1$ fm and\n$L\\simeq 7.6$ fm.",
        "positive": "O(a^2) improvement of the overlap-Dirac operator: We construct an $O(a^2)$-improved overlap-Dirac operator by designing an\nimproved overlap kernel, based on the Symanzik improvement program. Field\nrotation terms are also identified to improve off-shell amplitudes for both\nmassless and massive fermions. We check the free dispersion relation and\npropagator, and show that improved results become to close to the continuum\nones at low momentum region. We test the effect of improvement on the full-QCD\ngauge configuration and find that the relativistic dispersion relation is\nsatisfied within a few percent error up to $m_qa \\approx 0.5$."
    },
    {
        "anchor": "Strangeness of the nucleon from Lattice Quantum Chromodynamics: We present a non-perturbative calculation of the strangeness of the nucleon\n$y_N$ within the framework of lattice QCD. This observable is known to be an\nimportant cornerstone to interpret results from direct dark matter detection\nexperiments. We perform a lattice computation for $y_N$ with an analysis of\nsystematic effects originating from discretization, finite size, chiral\nextrapolation and excited state effects leading to the value of $y_N=\n0.173(50)$. The rather large uncertainty of this value of $y_N$ is dominated by\nsystematic uncertainties which we were able to quantify in this work.",
        "positive": "Patterns of flavour symmetry breaking in hadron matrix elements\n  involving u, d and s quarks: By considering a flavour expansion about the SU(3)-flavour symmetric point,\nwe investigate how flavour-blindness constrains octet baryon matrix elements\nafter SU(3) is broken by the mass difference between quarks. Similarly to\nhadron masses we find the expansions to be constrained along a mass trajectory\nwhere the singlet quark mass is held constant, which provides invaluable\ninsight into the mechanism of flavour symmetry breaking and proves beneficial\nfor extrapolations to the physical point. Expansions are given up to third\norder in the expansion parameters. Considering higher orders would give no\nfurther constraints on the expansion parameters. The relation of the expansion\ncoefficients to the quark-line-connected and quark-line disconnected terms in\nthe 3-point correlation functions is also given. As we consider Wilson\nclover-like fermions, the addition of improvement coefficients is also\ndiscussed and shown to be included in the formalism developed here. As an\nexample of the method we investigate this numerically via a lattice calculation\nof the flavour-conserving matrix elements of the vector first class form\nfactors."
    },
    {
        "anchor": "Tuning of QCD+QED simulations with C$^{\\star}$ boundary conditions: We give an update on the ongoing effort of the RC$^\\star$ collaboration to\ngenerate fully dynamical QCD+QED ensembles with C$^\\star$ boundary conditions\nusing the openQ$^\\star$D code. The simulations were tuned to the U-symmetric\npoint ($m_d = m_s$) with pions at $m_{\\pi^{\\pm}} \\approx 400$ MeV. The\nsplitting of the light mesons is used as one of three tuning observables and\nfixed to $m_{K^{0}} - m_{K^{\\pm}} \\approx 5$ MeV and $m_{K^{0}} - m_{K^{\\pm}}\n\\approx 25$ MeV on ensembles with renormalized electromagnetic coupling\n$\\alpha_{\\text{R}} \\approx \\alpha_{\\text{phys}}$ and $\\alpha_R \\approx\n5.5\\alpha_{phys}$ respectively. The tuning of the three independent quark\nmasses to the desired lines of constant physics is particularly challenging. We\nwill define the chosen hadronic renormalization scheme, and we will present a\ntuning strategy based on a combination of mass reweighting and linear\ninterpolation to explore the parameter space. We will comment on finite-volume\neffects comparing meson masses on two different volumes with $m_{\\pi^{\\pm}} L\n\\approx 3.2$ and $m_{\\pi^{\\pm}} L \\approx 5.1$. We will also provide some\ntechnical details on our updated strategy to calculate the sign of the\nfermionic Pfaffian, which arises in presence of C$^\\star$ boundary conditions\nin place of the standard fermionic determinant. More technical details on the\ngeneration of the configurations can be found in J. L\\\"ucke's proceedings",
        "positive": "Measure of the path integral in lattice gauge theory: We show how to construct the measure of the path integral in lattice gauge\ntheory. This measure contains a factor beyond the standard Haar measure. Such\nfactor becomes relevant for the calculation of a single transition amplitude\n(in contrast to the calculation of ratios of amplitudes). Single amplitudes are\nrequired for computation of the partition function and the free energy. For\nU(1) lattice gauge theory, we present a numerical simulation of the transition\namplitude comparing the path integral with the evolution in terms of the\nHamiltonian, showing good agreement."
    },
    {
        "anchor": "Precision Lattice Computations in the Heavy Quark Sector: The phenomenology of the pseudo scalar mesons D_s and B_s and of the vector\nmesons D_s* and B_s* was investigated in simulations of quenched lattice QCD.\nThe work is particularly focused on the continuum limit and the minimisation of\nall systematic errors within the quenched approximation. The decay constants\nF_Ds and F_Ds* and the difference in the masses between the D_s and the D_s*\nwere determined from the direct computer simulation of lattice QCD in large\nphysical volume (L ~ 1.5 fm). As an aside, the renormalisation group invariant\ncharm quark mass M_c could be obtained from the simulation results. For the\nB_s- and the B_s*-meson, an interpolation in the meson mass to its physical\npoint was carried out for the decay constant and the mass splitting in the\ncontinuum limit. The functional form of the interpolation to the static limit\nwas guided by the prediction of the Heavy Quark Effective Theory (HQET). A set\nof conversion functions between HQET and QCD were derived and evaluated\nnumerically with input from perturbation theory.",
        "positive": "Confinement of color and geometry: A natural explanation of confinement can be given in terms of symmetry. Since\ncolor symmetry is exact, the candidate symmetry is dual and related to\nhomotopy,i.e., in (3+1)d, to magnetic charge conservation. A set of r abelian\n'tHooft-like tensors (r = rank of the gauge group) can be defined and the dual\ncharge is a violation of the corresponding Bianchi identities. It is shown that\nthis is equivalently described by non-abelian Bianchi identities."
    },
    {
        "anchor": "Finite-Size Effects in Lattice QCD with Dynamical Wilson Fermions: As computing resources are limited, choosing the parameters for a full\nLattice QCD simulation always amounts to a compromise between the competing\nobjectives of a lattice spacing as small, quarks as light, and a volume as\nlarge as possible. Aiming to push unquenched simulations with the Wilson action\ntowards the computationally expensive regime of small quark masses we address\nthe question whether one can possibly save computing time by extrapolating\nresults from small lattices to the infinite volume, prior to the usual chiral\nand continuum extrapolations. In the present work the systematic volume\ndependence of simulated pion and nucleon masses is investigated and compared\nwith a long-standing analytic formula by Luescher and with results from Chiral\nPerturbation Theory. We analyze data from Hybrid Monte Carlo simulations with\nthe standard (unimproved) two-flavor Wilson action at two different lattice\nspacings of a=0.08fm and 0.13fm. The quark masses considered correspond to\napproximately 85 and 50% (at the smaller a) and 36% (at the larger a) of the\nstrange quark mass. At each quark mass we study at least three different\nlattices with L/a=10 to 24 sites in the spatial directions (L=0.85-2.08fm).",
        "positive": "Large N meson masses from a matrix model: We explain how to compute meson masses in the large $N$ limit using the\ntwisted Eguchi-Kawai model. A very simple formula is derived, and we show how\nit leads in a fast and efficient way to results which are in fairly good\nagreement with other determinations. The method is easily extensible to reduced\nmodels with dynamical fermions based on the twisted reduction idea."
    },
    {
        "anchor": "Lattice Calculation of the Connected Hadronic Light-by-Light\n  Contribution to the Muon Anomalous Magnetic Moment: The anomalous magnetic moment of muon, $g-2$, is a very precisely measured\nquantity. However, the current measurement disagrees with standard model by\nabout 3 standard deviations. Hadronic vacuum polarization and hadronic light by\nlight are the two types of processes that contribute most to the theoretical\nuncertainty. I will describe how lattice methods are well-suited to provide a\nfirst-principle's result for the hadronic light by light contribution, the\nvarious numerical strategies that are presently being used to evaluate it, our\ncurrent results and the important remaining challenges which must be overcome.",
        "positive": "Quantum Monte Carlo simulation with a black hole: We perform quantum Monte Carlo simulations in the background of a classical\nblack hole. The lattice discretized path integral is numerically calculated in\nthe Schwarzschild metric and in its approximated metric. We study spontaneous\nsymmetry breaking of a real scalar field theory. We observe inhomogeneous\nsymmetry breaking induced by inhomogeneous gravitational field."
    },
    {
        "anchor": "K0-K0bar mixing from the Schroedinger functional and twisted mass QCD: We describe how the Schroedinger functional and twisted mass QCD can be used\nto compute the kaon B-parameter B_K on the lattice with Wilson fermions. This\nnew approach is expected to reduce the systematic uncertainties on B_K through\na better control of its (nonperturbative) renormalisation. Preliminary results\nfor the bare matrix element in a physical volume of (1.5^3 x 4.5) fm^4 are\npresented. The renormalisation of the matrix element in a Schroedinger\nfunctional scheme is also discussed.",
        "positive": "Estimates of Scaling Violations for Pure SU(2) LGT: We investigate the approach of pure SU(2) lattice gauge theory with the\nWilson action to its continuum limit using the deconfining transition,\nLuescher's gradient flow, and the cooling flow to set the scale. Of those, the\ncooling flow turns out to be computationally most efficient. We explore\nsystematic errors due to use of three different energy observables and two\ndistinct reference values for the flow time, the latter obtained by matching\ninitial scaling behavior of some energy observables to that of the deconfining\ntransition. Another important source of systematic errors are distinct fitting\nforms for the approach to the continuum limit. Besides relying in the\nconventional way on ratios of masses, we elaborate on a form introduced by\nAllton, which incorporates asymptotic scaling behavior. Ultimately we find\nthat, though still small, our systematic errors are considerably larger than\nour statistical errors. ~"
    },
    {
        "anchor": "Gauge Theory and String Theory; An Introduction to the AdS/CFT\n  Correspondence: Plenary talk at the conference, LATTICE 99, held in Pisa, Itay from June 29\nto July 3, 1999.",
        "positive": "Four-point renormalized coupling constant in O(N) models: The renormalized zero-momentum four-point coupling $g_r$ of O(N)-invariant\nscalar field theories in $d$ dimensions is studied by applying the 1/N\nexpansion and strong coupling analysis. The O(1/N) correction to the\n$\\beta$-function and to the fixed point value $g_r^*$ are explictly computed.\nStrong coupling series for lattice non-linear sigma models are analyzed near\ncriticality in d=2 and d=3 for several values of $N$ and the corresponding\nvalues of $g_r^*$ are extracted. Large-N and strong coupling results are\ncompared with each other, finding a good general agreement. For small N the\nstrong coupling analysis in 2-d gives the best determination of $g^*_r$ to date\n(or comparable for N=2,3 with the available Monte Carlo estimates), and in 3-d\nit is consistent with available $\\phi^4$ field theory results."
    },
    {
        "anchor": "Effective action for the Abelian-Higgs model for a gauge-invariant\n  implementation on optical lattices: We present a gauge-invariant effective action for the Abelian-Higgs model in\n1+1 dimensions. It is constructed by integrating out the gauge field and then\nusing the hopping parameter expansion. The latter is tested with Monte Carlo\nsimulations for small values of the scalar self-coupling. In the opposite\nlimit, at infinitely large self-coupling, the Higgs mode is frozen and the\npartition function can be written in terms of local tensors and the tensor\nrenormalization group blocking can be applied. The numerical implementation\nrequires truncations and the time continuum limit of the blocked transfer\nmatrix can be obtained numerically. At zero gauge coupling and with a spin-1\ntruncation, the small volume energy spectrum is identical to the low energy\nspectrum of a two-species Bose-Hubbard model in the limit of large onsite\nrepulsion. The procedure is extended to finite gauge coupling and we derive a\nspin-1 approximation of the Hamiltonian which involves terms corresponding to\ntransitions among the two species in the Bose-Hubbard model. An optical lattice\nimplementation involving a ladder structure is proposed.",
        "positive": "Vector two-point functions in finite volume using partially quenched\n  chiral perturbation theory: We calculate vector-vector correlation functions at two loops using partially\nquenched chiral perturbation theory including finite volume effects and twisted\nboundary conditions. We present expressions for the flavor neutral cases and\nthe flavor charged case with equal masses. Using these expressions we give an\nestimate for the ratio of disconnected to connected contributions for the\nstrange part of the electromagnetic current. We give numerical examples for the\neffects of partial quenching, finite volume and twisting and suggest the use of\ndifferent twists to check the size of finite volume effects. The main use of\nthis work is expected to be for lattice QCD calculations of the hadronic vacuum\npolarization contribution to the muon anomalous magnetic moment."
    },
    {
        "anchor": "Variational study of U(1) and SU(2) lattice gauge theories with Gaussian\n  states in 1+1 dimensions: We introduce a method to investigate the static and dynamic properties of\nboth Abelian and non-Abelian lattice gauge models in 1+1 dimensions.\nSpecifically, we identify a set of transformations that disentangle different\ndegrees of freedom, and apply a simple Gaussian variational ansatz to the\nresulting Hamiltonian. To demonstrate the suitability of the method, we analyze\nboth static and dynamic aspects of string breaking for the U(1) and SU(2) gauge\nmodels. We benchmark our results against tensor network simulations and observe\nexcellent agreement, although the number of variational parameters in the\nGaussian ansatz is much smaller.",
        "positive": "Bilinear condensate in three-dimensional large-$N_c$ QCD: We find clear numerical evidence for a bilinear condensate in\nthree-dimensional QCD in the 't Hooft limit. We use a non-chiral random matrix\nmodel to extract the value of the condensate $\\Sigma$ from the low-lying\neigenvalues of the massless anti-Hermitian overlap Dirac operator. We estimate\n$\\Sigma/\\lambda^2 = 0.0042 \\pm 0.0004$ in units of the physical 't Hooft\ncoupling."
    },
    {
        "anchor": "New configuration set of HAL QCD collaboration: We give a brief report on the basic properties and cutoff scale of our new\nconfiguration set (HAL-Conf-2023). We generated 8,000 trajectories of the gauge\nconfigurations on $96^4$ lattices with the same lattice parameters as the PACS\ncollaboration \\cite{Ishikawa:2018jee, PACS:2019ofv}. The topological\ndistribution, the PCAC masses, and decay constants for pseudo-scalar mesons are\nstudied. As for the scale setting, we utilize the $\\Omega$ baryon mass as a\nreference scale and carefully investigate the operator dependence of the\ncorrelation function. As a result, we obtain $a^{-1}=2338.8(1.5)^{+0.2}_{-3.3}\n\\ [{\\rm MeV}]$ as a lattice cutoff. Our hadron spectra in the physical unit\nreproduce well the experimental results.",
        "positive": "2+1 Flavor Lattice QCD toward the Physical Point: We present the first results of the PACS-CS project which aims to simulate\n2+1 flavor lattice QCD on the physical point with the nonperturbatively\n$O(a)$-improved Wilson quark action and the Iwasaki gauge action. Numerical\nsimulations are carried out at the lattice spacing of $a=0.0907(13)$fm on a\n$32^3\\times 64$ lattice with the use of the DDHMC algorithm to reduce the\nup-down quark mass. Further algorithmic improvements make possible the\nsimulation whose ud quark mass is as light as the physical value. The resulting\nPS meson masses range from 702MeV down to 156MeV, which clearly exhibit the\npresence of chiral logarithms. An analysis of the PS meson sector with SU(3)\nChPT reveals that the NLO corrections are large at the physical strange quark\nmass. In order to estimate the physical ud quark mass, we employ the SU(2)\nchiral analysis expanding the strange quark contributions analytically around\nthe physical strange quark mass. The SU(2) LECs ${\\bar l}_3$ and ${\\bar l}_4$\nare comparable with the recent estimates by other lattice QCD calculations. We\ndetermine the physical point together with the lattice spacing employing\n$m_\\pi$, $m_K$ and $m_\\Omega$ as input. The hadron spectrum extrapolated to the\nphysical point shows an agreement with the experimental values at a few % level\nof statistical errors, albeit there remain possible cutoff effects. We also\nfind that our results of $f_\\pi=134.0(4.2)$MeV, $f_K=159.4(3.1)$MeV and\n$f_K/f_\\pi=1.189(20)$ with the perturbative renormalization factors are\ncompatible with the experimental values. For the physical quark masses we\nobtain $m_{\\rm ud}^\\msbar=2.527(47)$MeV and $m_{\\rm s}^\\msbar=72.72(78)$MeV\nextracted from the axial-vector Ward-Takahashi identity with the perturbative\nrenormalization factors."
    },
    {
        "anchor": "The Gluon Chain Model Revisited: I describe how the gluon chain model of QCD string formation meets a number\nof criteria which are required of any theory of the confining force, including:\nthe correct center dependence and (at large-N) Casimir scaling of the string\ntension, the logarithmic broadening of the QCD flux tube, and the existence of\na Luscher term in the static quark potential.",
        "positive": "The strong coupling from a nonperturbative determination of the\n  $\u039b$ parameter in three-flavor QCD: We present a lattice determination of the $\\Lambda$ parameter in three-flavor\nQCD and the strong coupling at the Z pole mass. Computing the nonperturbative\nrunning of the coupling in the range from $0.2\\,$GeV to $70\\,$GeV, and using\nexperimental input values for the masses and decay constants of the pion and\nthe kaon, we obtain $\\Lambda_{\\overline{\\rm MS}}^{(3)}=341(12)\\,$MeV. The\nnonperturbative running up to very high energies guarantees that systematic\neffects associated with perturbation theory are well under control. Using the\nfour-loop prediction for $\\Lambda_{\\overline{\\rm\nMS}}^{(5)}/\\Lambda_{\\overline{\\rm MS}}^{(3)}$ yields\n$\\alpha^{(5)}_{\\overline{\\rm MS}}(m_{\\rm Z}) = 0.11852(84)$."
    },
    {
        "anchor": "Deconfinement and chiral transition with the highly improved staggered\n  quark (HISQ) action: We report on investigations of the chiral and deconfinement aspects of the\nfinite temperature transition in 2+1 flavor QCD using the Highly Improved\nStaggered Quark (HISQ) action on lattices with temporal extent $N_\\tau=6$ and\n$N_\\tau=8$. We have performed the calculations for physical values of the\nstrange quark mass $m_s$ and the light quark masses $m_l=0.2m_s$ and $0.05m_s$.\nSeveral finite temperature observables, including the renormalized Polyakov\nloop, the renormalized chiral condensate and the chiral susceptibility have\nbeen calculated. We also study the fluctuations and correlations of different\nconserved charges as well as the trace anomaly at finite temperature. We\ncompare our findings with previous calculations that use different improved\nstaggered fermion formulations: asqtad, p4 and stout.",
        "positive": "Fermion Determinants: Some Recent Analytic Results: The use of known analytic results for the continuum fermion determinants in\nQCD and QED as benchmarks for zero lattice spacing extrapolations of lattice\nfermion determinants is proposed. Specifically, they can be used as a check on\nthe universality hypothesis relating the continuum limits of the na\\\"{\\i}ve,\nstaggered and Wilson fermion determinants."
    },
    {
        "anchor": "The Gell-Mann -- Okubo mass relation among baryons from fully-dynamical\n  mixed-action lattice QCD: We explore the Gell-Mann--Okubo mass relation among the octet baryons using\nfully-dynamical, mixed-action (domain-wall on rooted-staggered) lattice QCD\ncalculations at a lattice spacing of b ~ 0.125 fm and pion masses of m_pi ~ 290\nMeV, 350 MeV, 490 MeV and 590 MeV. Deviations from the Gell-Mann--Okubo mass\nrelation are found to be small at each quark mass.",
        "positive": "Dirac spectrum representation of Polyakov loop fluctuations in lattice\n  QCD: Dirac spectrum representations of the Polyakov loop fluctuations are derived\non the temporally odd-number lattice, where the temporal length is odd with the\nperiodic boundary condition. We investigate the Polyakov loop fluctuations\nbased on these analytical relations. It is semianalytically and numerically\nfound that the low-lying Dirac eigenmodes have little contribution to the\nPolyakov loop fluctuations, which are sensitive probe for the quark\ndeconfinement. Our results suggest no direct one-to-one corresponding between\nquark confinement and chiral symmetry breaking in QCD."
    },
    {
        "anchor": "Thermal Dilepton Rates and Meson Spectral Functions from Lattice QCD: Pseudo-scalar and vector meson correlation functions were calculated at\ntemperatures below and above the deconfinement transition using ${\\cal O}(a)$\nimproved Wilson fermions in quenched lattice QCD. The spectral functions were\nreconstructed from the correlator given only at discrete points in Euclidean\ntime by means of the Maximum Entropy Method without a priori assumptions on the\nspectral shape. The deviation of the spectral functions from the one of a\nfreely propagating quark anti-quark pair is examined above the critical\ntemperature. At 1.5 and 3 $T_c$ the vector spectral function yields an\nenhancement of the dilepton rate over the Born rate in the energy interval $4 <\n\\omega/T < 8$ and a sharp drop at energies below 2-3 T.",
        "positive": "Polyakov Loop Correlations at Large N: I describe a study of the two-point single-eigenvalue distribution\ncorrelation function of Polyakov loops in the confined phase of four\ndimensional SU(N) YM theory at large N. The reasons for the interest in this\ncorrelation function are explained. Analytical and numerical results are\npresented. Brief conclusions are drawn."
    },
    {
        "anchor": "The static potential beyond screening in the 3d SU(2) Higgs model: The static potential in the 3d SU(2) Higgs model is computed by a variational\ncalculation employing Wilson loops and two-meson operators. String breaking is\ndemonstrated numerically, the breaking scale is determined and the results are\ncompared with a quenched calculation.",
        "positive": "Patterns of flavour symmetry breaking in hadron matrix elements\n  involving u, d and s quarks: Using an SU(3)-flavour symmetry breaking expansion between the strange and\nlight quark masses, we determine how this constrains the extrapolation of\nbaryon octet matrix elements and form factors. In particular we can construct\ncertain combinations, which fan out from the symmetric point (when all the\nquark masses are degenerate) to the point where the light and strange quarks\ntake their physical values. As a further example we consider the vector\namplitude at zero momentum transfer for flavour changing currents."
    },
    {
        "anchor": "SU(3) Deconfinement in (2+1)d from Twisted Boundary Conditions and\n  Self-Duality: We study the pure SU(3) gauge theory in 2+1 dimensions on the lattice using\n't Hooft's twisted boundary conditions to force non-vanishing center flux\nthrough the finite volume. In this way we measure the free energy of spacelike\ncenter vortices as an order parameter for the deconfinement transition. The\ntransition is of 2nd order in the universality class of the 2d 3-state Potts\nmodel, which is self-dual. This self-duality can be observed directly in the\nSU(3) gauge theory, and it can be exploited to extract critical couplings with\nhigh precision in rather small volumes. We furthermore obtain estimates for\ncritical exponents and the critical temperature in units of the dimensionful\ncontinuum coupling. Finally, we also apply our methods to the (2+1)d SU(4)\ngauge theory which was previously found to have a weak 1st order transition. We\nnevertheless observe at least approximate q = 4 Potts scaling at length scales\ncorresponding to the lattice sizes used in our simulations.",
        "positive": "Relation between scattering amplitude and Bethe-Salpeter wave function\n  in quantum field theory: We discuss an exact relation between the two-particle scattering amplitude\nand the Bethe-Salpeter (BS) wave function inside the interaction range in\nquantum field theory. In the relation the reduced BS wave function defined by\nthe BS wave function plays an essential role. Through the relation the on-shell\nand half off-shell amplitudes can be calculated. We also show that the solution\nof Schr\\\"odinger equation with the effective potential determined from the BS\nwave function gives a correct on-shell scattering amplitude only at the\nmomentum where the effective potential is determined. Furthermore we discuss a\nderivative expansion of the reduced BS wave function and a condition to obtain\nresults independent of the interpolating operators in the time-dependent HALQCD\nmethod."
    },
    {
        "anchor": "Hadron spectra and Delta_{mix} from overlap quarks on a HISQ sea: We present results of our continuing study on mixed-action hadron spectra and\ndecay constants using overlap valence quarks on MILC's 2+1+1 flavor HISQ gauge\nconfigurations. This study is carried out on three lattice spacings, with charm\nand strange masses tuned to their physical values, and with m_l/m_s = 1/5. We\npresent results of an ongoing determination of the mixed-action parameter\nDelta_{mix}, which enters into chiral formulae for the masses and decay\nconstants.",
        "positive": "Partially quenched study of strange baryon with Nf = 2 twisted mass\n  fermions: We present results on the mass of the baryon octet and decuplet using two\nflavors of light dynamical twisted mass fermions. The strange quark mass is\nfixed to its physical value from the kaon sector in a partially quenched set\nup. Calculations are performed for light quark masses corresponding to a pion\nmass in the range 270-500 MeV and lattice sizes of 2.1 fm and 2.7 fm. We check\nfor cut-off effects and isospin breaking by evaluating the baryon masses at two\ndifferent lattice spacings. We carry out a chiral extrapolation for the octet\nbaryons and discuss results for the Omega."
    },
    {
        "anchor": "Chiral and deconfinement transitions in strong coupling lattice QCD with\n  finite coupling and Polyakov loop effects: We investigate chiral and deconfinement transitions in the framework of the\nstrong coupling lattice QCD for color SU(3) with one species of unrooted\nstaggered fermion at finite temperature and quark chemical potential. We take\naccount of the leading order Polyakov loop terms as well as the\nnext-to-next-to-leading order (1/g^4) fermionic terms of the strong coupling\nexpansion in the effective action. We investigate the Polyakov loop effects by\ncomparing two approximation schemes, a Haar measure method (no fluctuation from\nthe mean field) and a Weiss mean-field method (with fluctuations). The\neffective potential is obtained in both cases, and we analytically clarify the\nPolyakov loop contributions to the effective potential. The Polyakov loop is\nfound to suppress the chiral condensate and to reduce the chiral transition\ntemperature at mu=0, and the chiral transition temperature roughly reproduces\nthe Monte Carlo results at beta=2N_c/g^2 \\lesssim 4. The deconfinement\ntransition is found to be the crossover and first order for light (am_0\n\\lesssim 4 at beta=4) and heavy quark masses, respectively.",
        "positive": "Lattice effective theory and the phase transition at finite densities: The transition from the hadronic phase to the phase of\ncolor-superconductivity at large densities is addressed by an effective theory\nwhich incorporates the Yang-Mills dynamics in addition to the di-quark degree\nof freedom. A toy version of this theory is studied by lattice simulations. A\nfirst order phase transition separates the regime of broken color-electric flux\ntubes from the color superconducting phase. My findings suggest that the quark\nand gluon liberation occurs at the same critical chemical potential."
    },
    {
        "anchor": "Simulation Results for U(1) Gauge Theory on Non-Commutative Spaces: We present numerical results for U(1) gauge theory in 2d and 4d spaces\ninvolving a non-commutative plane. Simulations are feasible thanks to a mapping\nof the non-commutative plane onto a twisted matrix model. In d=2 it was a\nlong-standing issue if Wilson loops are (partially) invariant under\narea-preserving diffeomorphisms. We show that non-perturbatively this\ninvariance breaks, including the subgroup SL(2,R). In both cases, d=2 and d=4,\nwe extrapolate our results to the continuum and infinite volume by means of a\nDouble Scaling Limit. In d=4 this limit leads to a phase with broken\ntranslation symmetry, which is not affected by the perturbatively known IR\ninstability. Therefore the photon may survive in a non-commutative world.",
        "positive": "Gluon propagators and center vortices at finite temperature: We study influence of center vortices on infrared properties of gluons in the\ndeconfinement phase of quenched QCD. We observe a significant suppression of\nthe magnetic component of the gluon propagator in the low-momentum region after\nthe vortices are removed from the gluon configurations. The propagator of the\nelectric gluon stays almost unaffected by the vortex removal. Our results\ndemonstrate that the center vortices are responsible for important\nnonperturbative properties of the magnetic component of the quark-gluon plasma."
    },
    {
        "anchor": "The order of the phase transition in 3d U(1)+Higgs theory: We study the order of the phase transition in the 3d U(1)+Higgs theory, which\nis the Ginzburg-Landau theory of superconductivity. We confirm that for small\nscalar self-coupling the transition is of first order. For large scalar\nself-coupling the transition ceases to be of first order, and a non-vanishing\nscalar mass suggests that the transition may even be of higher than second\norder.",
        "positive": "Quantum fluctuations of k-strings: A case study: K strings in Yang-Mills theory can be considered as bound states of k\nelementary confining strings carrying one unit of colour flux. Current\nestimates of k-string tension sigma_k are very sensitive to the leading\ncorrections due to quantum fluctuations of the string. In this study we address\nthis problem by comparing Polyakov-Polyakov correlators in the fundamental\nrepresentation (k=1) with the corresponding ones with k=2 in the confining\nphase of a Z_4 gauge theory in three dimensions. Highly efficient simulation\ntechniques are available in this case. Although the k=1 Polyakov-Polyakov\ncorrelator matches nicely with the expected bosonic string effects up to the\nNext-to-Leading-Order, the k=2 Polyakov-Polyakov correlators show large\ndeviations. This is an important source of potential systematic errors in the\ncurrent estimates of sigma_k."
    },
    {
        "anchor": "Free Energy and Plaquette expectation value for gluons on the lattice,\n  in three dimensions: We calculate the perturbative value of the Free Energy in Lattice QCD in\nthree dimensions, up to three loops. Our calculation is performed using the\nWilson formulation for gluons in SU(N) gauge theories.\n  The Free Energy is directly related to the average plaquette. To carry out\nthe calculation, we compute the coefficients involved in the perturbative\nexpansion of the Free Energy up to three loops, using an automated set of\nprocedures developed by us in Mathematica. The dependence on N is shown\nexplicitly in our results.\n  For purposes of comparison, we also present the individual contributions from\nevery diagram. These have been obtained by means of two independent\ncalculations, in order to cross check our results.",
        "positive": "Finite Size Scaling of the Higgs-Yukawa Model near the Gaussian Fixed\n  Point: We study the scaling properties of Higgs-Yukawa models. Using the technique\nof Finite-Size Scaling, we are able to derive scaling functions that describe\nthe observables of the model in the vicinity of a Gaussian fixed point. A\nfeasibility study of our strategy is performed for the pure scalar theory in\nthe weak-coupling regime. Choosing the on-shell renormalisation scheme gives us\nan advantage to fit the scaling functions against lattice data with only a\nsmall number of fit parameters. These formulae can be used to determine the\nuniversality of the observed phase transitions, and thus play an essential role\nin future investigations of Higgs-Yukawa models, in particular in the strong\nYukawa coupling region."
    },
    {
        "anchor": "Finite $ma$ corrections for sea quark matrix elements on the lattice: We compute the $ma$ dependence of lattice renormalization factors for sea\nquark matrix elements. The results differ from the $(1+ma)$ correction factor\ncommonly used for valence quarks and connected current insertions. We find that\nfor sea quarks, the correction factors are in general larger and depend\nstrongly on the Lorentz structure of the current under consideration. Results\nare presented both for the Wilson action and for the 2-link improved action of\nHamber and Wu. Phenomenological implications are also briefly discussed in two\nexamples.",
        "positive": "Higher order quark number fluctuations via imaginary chemical potentials\n  in $N_f=2+1$ QCD: We discuss analytic continuation as a tool to extract the cumulants of the\nquark number fluctuations in the strongly interacting medium from lattice QCD\nsimulations at imaginary chemical potentials. The method is applied to $N_f =\n2+1$ QCD, discretized with stout improved staggered fermions, physical quark\nmasses and the tree level Symanzik gauge action, exploring temperatures ranging\nfrom 135 up to 350 MeV and adopting mostly lattices with $N_t = 8$ sites in the\ntemporal direction. The method is based on a global fit of various cumulants as\na function of the imaginary chemical potentials. We show that it is\nparticularly convenient to consider cumulants up to order two, and that below\n$T_c$ the method can be advantageous, with respect to a direct Montecarlo\nsampling at $\\mu = 0$, for the determination of generalized susceptibilities of\norder four or higher, and especially for mixed susceptibilities, for which the\ngain is well above one order of magnitude. We provide cumulants up to order\neight, which are then used to discuss the radius of convergence of the Taylor\nexpansion and the possible location of the second order critical point at real\n$\\mu$: no evidence for such a point is found in the explored range of $T$ and\nfor chemical potentials within present determinations of the pseudo-critical\nline."
    },
    {
        "anchor": "Design and optimization of a portable LQCD Monte Carlo code using\n  OpenACC: The present panorama of HPC architectures is extremely heterogeneous, ranging\nfrom traditional multi-core CPU processors, supporting a wide class of\napplications but delivering moderate computing performance, to many-core GPUs,\nexploiting aggressive data-parallelism and delivering higher performances for\nstreaming computing applications. In this scenario, code portability (and\nperformance portability) become necessary for easy maintainability of\napplications; this is very relevant in scientific computing where code changes\nare very frequent, making it tedious and prone to error to keep different code\nversions aligned. In this work we present the design and optimization of a\nstate-of-the-art production-level LQCD Monte Carlo application, using the\ndirective-based OpenACC programming model. OpenACC abstracts parallel\nprogramming to a descriptive level, relieving programmers from specifying how\ncodes should be mapped onto the target architecture. We describe the\nimplementation of a code fully written in OpenACC, and show that we are able to\ntarget several different architectures, including state-of-the-art traditional\nCPUs and GPUs, with the same code. We also measure performance, evaluating the\ncomputing efficiency of our OpenACC code on several architectures, comparing\nwith GPU-specific implementations and showing that a good level of\nperformance-portability can be reached.",
        "positive": "Semileptonic $B_c$ decays from full lattice QCD: We present first lattice QCD results for semileptonic form factors for the\ndecays $B_c \\to \\eta_c l \\nu$ and $B_c \\to J/\\psi l \\nu$ over the full $q^2$\nrange, using both improved non-relativistic QCD (NRQCD) and fully relativistic\n(HISQ) formalisms. These can be viewed as prototype calculations for\npseudoscalar to pseudoscalar and pseudoscalar to vector decays involving a $b\n\\to c$ transition. In particular we can use information from the relativistic\ncomputations to fix the NRQCD current normalisations, which can then be used in\nimproved computations of decays such as $B \\to D l \\nu$ and $B \\to D^* l \\nu$."
    },
    {
        "anchor": "Semi-leptonic decays of heavy mesons and the Isgur-Wise function in\n  quenched lattice QCD: The form factors for the semi-leptonic B->D and B->D* decays are evaluated in\nquenched lattice QCD at two different values of the coupling, beta=6.0 and 6.2.\nThe action and the operators are fully O(a) non-perturbatively improved. The\nslope of the Isgur-Wise function is evaluated, and found to be\nrho^2=0.83^{+15+24}_{-11-1} (quoted errors are statistical and systematic\nrespectively). Ratios of form factors are evaluated and compared to\nexperimental determinations.",
        "positive": "Dual Superconductivity and Chiral Symmetry in Full QCD: A disorder parameter detecting dual superconductivity of the vacuum is\nmeasured across the chiral phase transition in full QCD with two flavours of\ndynamical staggered fermions. The observed behaviour is similar to the quenched\ncase."
    },
    {
        "anchor": "Magnetic susceptibility of QCD at zero and at finite temperature from\n  the lattice: The response of the QCD vacuum to a constant external (electro)magnetic field\nis studied through the tensor polarization of the chiral condensate and the\nmagnetic susceptibility at zero and at finite temperature. We determine these\nquantities using lattice configurations generated with the tree-level Symanzik\nimproved gauge action and N_f=1+1+1 flavors of stout smeared staggered quarks\nwith physical masses. We carry out the renormalization of the observables under\nstudy and perform the continuum limit both at T>0 and at T=0, using different\nlattice spacings. Finite size effects are studied by using various spatial\nlattice volumes. The magnetic susceptibilities \\chi_f reveal a diamagnetic\nbehavior; we obtain at zero temperature \\chi_u=-(2.08 +/- 0.08) 1/GeV^2,\n\\chi_d=-(2.02 +/- 0.09) 1/GeV^2 and \\chi_s=-(3.4 +/- 1.4) 1/GeV^2 for the up,\ndown and strange quarks, respectively, in the MSBar scheme at a renormalization\nscale of 2 GeV. We also find the polarization to change smoothly with the\ntemperature in the confinement phase and then to drastically reduce around the\ntransition region.",
        "positive": "Gribov copies, Lattice QCD and the gluon propagator: We address the problem of Gribov copies in lattice QCD. The gluon propagator\nis computed, in the Landau gauge, using 302 ($\\beta = 5.8$) $12^4$\nconfigurations gauge fixed to different copies. The results of the simulation\nshows that: i) the effect of Gribov copies is small (less than 10%); ii) Gribov\ncopies change essentially the lowest momenta components ($q < 2.6$ GeV); iii)\nwithin the statistical accuracy of our simulation, the effect of Gribov copies\nis resolved if statistical errors are multiplied by a factor of two or three.\nMoreover, when modelling the gluon propagator, different sets of Gribov copies\nproduce different sets of parameters not, necessarily, compatible within one\nstandard deviation. Finally, our data supports a gluon propagator which, for\nlarge momenta, behaves like a massive gluon propagator with a mass of 1.1 GeV."
    },
    {
        "anchor": "Constituent gluons and the static quark potential: We suggest that Hamiltonian matrix elements between physical states in QCD\nmight be approximated, in Coulomb gauge, by \"lattice-improved\" tree diagrams;\ni.e. tree diagram contributions with dressed ghost, transverse gluon, and\nCoulomb propagators obtained from lattice simulations. Such matrix elements can\nbe applied to a truncated-basis treatment of hadronic states which include\nconstituent gluons. As an illustration, we apply this hybrid approach to the\nheavy quark potential, for quark-antiquark separations up to 2.4 fm. The\nCoulomb string tension in SU(3) gauge theory is about a factor of four times\ngreater than the asymptotic string tension. In our approach we show that a\nsingle constituent gluon is in principle sufficient, up to 2.4 fm, to reduce\nthis overshoot by the factor required. The static potential remains linear,\nalthough the precise value of the string tension depends on details of the\nCouloumb gauge ghost and gluon propagators in the infrared regime. In this\nconnection we present new lattice results for the transverse gluon propagator\nin position space.",
        "positive": "Scaling Properties of the Energy Density in SU(2) Lattice Gauge Theory: The lattice data for the energy density of $SU(2)$ gauge theory are\ncalculated with \\nop~derivatives of the coupling constants. These derivatives\nare obtained from two sources : i) a parametrization of the \\nop~beta function\nin accord with the measured critical temperature and $\\Delta\\beta-$values and\nii) a \\nop~calculation of the presssure. We then perform a detailed finite size\nscaling analysis of the energy density near $T_c$. It is shown that at the\ncritical temperature the energy density is scaling as a function of $VT^3$ with\nthe corresponding $3d$ Ising model critical exponents. The value of\n$\\epsilon(T_c)/T^4_c$ in the continuum limit is estimated to be 0.256(23). In\nthe high temperature regime the energy density is approaching its weak coupling\nlimit from below, at $T/T_c \\approx 2$ it has reached only about $70\\%$ of the\nlimit."
    },
    {
        "anchor": "Non-perturbative renormalisation and improvement of non-singlet tensor\n  currents in $N_\\mathrm{f}=3$ QCD: Hadronic matrix elements involving tensor currents play an important r\\^ole\nin decays that allow to probe the consistency of the Standard Model via\nprecision lattice QCD calculations. The non-singlet tensor current is a\nscale-dependent (anomalous) quantity. We fully resolve its renormalisation\ngroup (RG) running in the continuum by carrying out a recursive finite-size\nscaling technique. In this way ambiguities due to a perturbative RG running and\nmatching to lattice data at low energies are eliminated. We provide the total\nrenormalisation factor at a hadronic scale of 233 MeV, which converts the bare\ncurrent into its RG-invariant form. Our calculation features three flavours of\nO(a) improved Wilson fermions and tree-level Symanzik-improved gauge action. We\nemploy the (massless) Schr\\\"odinger functional renormalisation scheme\nthroughout and present the first non-perturbative determination of the Symanzik\ncounterterm $c_\\mathrm{T}$ derived from an axial Ward identity. We elaborate on\nvarious details of our calculations, including two different renormalisation\nconditions.",
        "positive": "Lattice QCD at High Temperature and Density: After a brief introduction into basic aspects of the formulation of lattice\nregularized QCD at finite temperature and density we discuss our current\nunderstanding of the QCD phase diagram at finite temperature. We present\nresults from lattice calculations that emphasize the deconfining as well as\nchiral symmetry restoring features of the QCD transition, and discuss the\nthermodynamics of the high temperature phase."
    },
    {
        "anchor": "Flavour symmetry breaking and tuning the strange quark mass for 2+1\n  quark flavours: QCD lattice simulations with 2+1 flavours typically start at rather large\nup-down and strange quark masses and extrapolate first the strange quark mass\nto its physical value and then the up-down quark mass. An alternative method of\ntuning the quark masses is discussed here in which the singlet quark mass is\nkept fixed, which ensures that the kaon always has mass less than the physical\nkaon mass. Using group theory the possible quark mass polynomials for a Taylor\nexpansion about the flavour symmetric line are found, which enables highly\nconstrained fits to be used in the extrapolation of hadrons to the physical\npion mass. Numerical results confirm the usefulness of this expansion and an\nextrapolation to the physical pion mass gives hadron mass values to within a\nfew percent of their experimental values.",
        "positive": "$\u03c0\u03c0$ scattering at Large $N_\\text{c}$: We study the Large $N_\\text{c}$ scaling of pion-pion scattering amplitudes\nfor $N_\\text{f}=4$ degenerate quark flavors. We focus on the standard isospin-2\nchannel and the adjoint-antisymmetric (AA) representation. The latter only\nexists for $N_\\text{f}\\geq 4$ and a representative state is\n$\\frac{1}{\\sqrt{2}}(|D_s^+\\pi^+\\rangle-|D^+ K^+\\rangle)$. We compare the\nresults obtained for two regularizations (Wilson and twisted-mass fermions) and\nthree values of the lattice spacing, and observe significant discretization\neffects in the AA channel. Finally, we match our results to NLO SU(4) and NNLO\nU(4) Chiral Perturbation Theory and constrain the $N_\\text{c}$ scaling of the\nrelevant low-energy couplings."
    },
    {
        "anchor": "Effects of Chemical Potential on Hadron Masses at Finite Temperature: We study the effects of the chemical potential on the $\\rho$ meson mass at\nfinite temperature. Our preliminary results show that some effects are seen in\nthe vicinity of the phase transition point. Although the signal is still too\nnoisy to obtain conclusive physical results within limited statistics, the mass\nsusceptibility is consistent with zero.",
        "positive": "Electromagnetic corrections to pseudoscalar decay constants: The effects of electromagnetic interactions on pseudoscalar decay constants\nare investigated. Using a compact QED and QCD action we are able to resolve\ndifferences of about 0.1 MeV. We obtain the preliminary results f_pi^0-f_pi^+/-\n=0.09(3) MeV and f_D^0-f_D^+/- =0.79(11) MeV for light and charmed pseudoscalar\ndecay constants on a N_f=2 nonperturbatively improved Sheikholeslami-Wohlert\nensemble."
    },
    {
        "anchor": "Tempered transitions between thimbles: Quantum field theories with complex actions cannot be investigated using\nimportance sampling due to the sign problem. One possible solution is to use\nthe holomorphic gradient flow, a method we introduced related to the Lefschetz\nthimbles idea. In many cases the probability distribution generated by this\nmethod is multi-modal and standard Monte-Carlo sampling fails. We propose an\nalgorithm that incorporates tempered proposals to solve this problem. We apply\nthis algorithm to the 0+1 dimensional Thirring model at finite density for a\nparameter set where standard sampling fails and show that tempered proposals\ncure this problem.",
        "positive": "Few-body physics: Few-body hadronic observables play an essential role in a wide number of\nprocesses relevant for both particle and nuclear physics. In order for Lattice\nQCD to offer insight into the interpretation of few-body states, a theoretical\ninfrastructure must be developed to map Euclidean-time correlation functions to\nthe desired Minkowski-time few-body observables. In this talk, I review the\nformal challenges associated with the studies of such systems via Lattice QCD,\nas first introduced by Maiani and Testa, and I also review the methodology to\ncircumvent said limitations. The first main example of the latter is the\nformalism by Luscher to analyze elastic scattering and a second is the method\nby Lellouch and Luscher to analyze weak decays. I discus recent theoretical\ngeneralizations of these frameworks that allow for the determination of\nscattering amplitudes, resonances, nonlocal contribution to matrix elements,\nand form factors below and above inelastic thresholds. Finally, I outline\noutstanding problems, including those that are now beginning to be addressed."
    },
    {
        "anchor": "QCD with a theta-vacuum term: a complex system with a simple complex\n  action: We reanalyze in the first part of this paper the old question of P and CT\nrealization in QCD. The second part is devoted to establish general results on\nthe phase structure of this model in the presence of a $\\theta$-vacuum term.",
        "positive": "Resonances in Coupled-Channel Scattering: Excited hadrons are seen as resonances in the scattering of lighter stable\nhadrons like $\\pi$, $K$ and $\\eta$. Many decay into multiple final states\nnecessitating coupled-channel analyses. Recently it has become possible to\nobtain coupled-channel scattering amplitudes from lattice QCD. Using large\ndiverse bases of operators it is possible to obtain reliable finite volume\nspectra at energies where multiple channels are open. Utilising the finite\nvolume formalism proposed by L\\\"uscher and extended by several others,\nscattering amplitudes can be extracted from the finite volume spectra. Recent\napplications will be discussed where the energy dependence of scattering\namplitudes is mapped out in several quantum numbers. These are then continued\nto complex energies to extract resonance poles and couplings."
    },
    {
        "anchor": "Tensor-network study of the 3d $O(2)$ model at non-zero chemical\n  potential and temperature: We present results of tensor-network simulations of the three-dimensional\n$O(2)$ model at non-zero chemical potential and temperature, which were\ncomputed using the higher-order tensor-renormalization-group method (HOTRG).\nThis necessitated enhancements to the HOTRG blocking procedure to reduce the\ntruncation error in the case of anisotropic tensors. Moreover, the construction\nof the truncated vector spaces was adapted to strongly reduce the effect of\nsystematic errors in the computation of observables using the finite-difference\nmethod. Our (improved) HOTRG results for the evolution of the number density\nwith the chemical potential are in agreement with results obtained with the\nworm algorithm, and both the Silver Blaze phenomenon at zero temperature and\nthe temperature dependence of the number density can be adequately reproduced.",
        "positive": "High precision renormalization of the flavour non-singlet Noether\n  currents in lattice QCD with Wilson quarks: We determine the non-perturbatively renormalized axial current for O($a$)\nimproved lattice QCD with Wilson quarks. Our strategy is based on the chirally\nrotated Schr\\\"odinger functional and can be generalized to other finite (ratios\nof) renormalization constants which are traditionally obtained by imposing\ncontinuum chiral Ward identities as normalization conditions. Compared to the\nlatter we achieve an error reduction up to one order of magnitude. Our results\nhave already enabled the setting of the scale for the $N_{\\rm f}=2+1$ CLS\nensembles [1] and are thus an essential ingredient for the recent $\\alpha_s$\ndetermination by the ALPHA collaboration [2]. In this paper we shortly review\nthe strategy and present our results for both $N_{\\rm f}=2$ and $N_{\\rm f}=3$\nlattice QCD, where we match the $\\beta$-values of the CLS gauge configurations.\nIn addition to the axial current renormalization, we also present precise\nresults for the renormalized local vector current."
    },
    {
        "anchor": "Quantum Simulation of Non-Abelian Lattice Gauge Theories: We use quantum link models to construct a quantum simulator for U(N) and\nSU(N) lattice gauge theories. These models replace Wilson's classical link\nvariables by quantum link operators, reducing the link Hilbert space to a\nfinite number of dimensions. We show how to embody these quantum link models\nwith fermionic matter with ultracold alkaline-earth atoms using optical\nlattices. Unlike classical simulations, a quantum simulator does not suffer\nfrom sign problems and can thus address the corresponding dynamics in real\ntime. Using exact diagonalization results we show that these systems share\nqualitative features with QCD, including chiral symmetry breaking and we study\nthe expansion of a chirally restored region in space in real time.",
        "positive": "The vector and axial vector current in Wilson ChPT: We construct the vector and axial vector currents in Wilson Chiral\nPerturbation Theory (WChPT), the low-energy effective theory for lattice QCD\nwith Wilson fermions.\n  Our construction is slightly different compared to ChPT in continuum QCD,\nwhere the currents are essentially the (partially) conserved currents\nassociated with the chiral symmetries. In WChPT, due to explicit chiral\nsymmetry breaking at non-zero lattice spacing, there appear O(a) terms in the\nexpressions for the currents which do not stem from the effective action. In\naddition, the finite renormalization of the currents needs to be taken into\naccount in order to properly match the currents of the effective theory.\n  As an illustration we compute f_pi to one loop with the renormalized axial\nvector current for a particular renormalization condition. It turns out that\nfor this particular condition some of the O(a) corrections are taken care of by\nthe renormalization."
    },
    {
        "anchor": "Lattice QCD study for the Quark-Gluon Mixed Condensate (anti-Q sigma G\n  Q): We study the quark-gluon mixed condensate g<\\bar{q} sigma G q>, which is\nanother chiral order parameter, using the SU(3)c lattice QCD with the\nKogut-Susskind(KS) fermion at the quenched level. We generate 100 gauge\nconfigurations on the 16^4 lattice with \\beta = 6.0, and measure the mixed\ncondensate at 16 points in each gauge configuration for each current-quark mass\nof m_q=21, 36, 52 MeV. From the 1600 data for each m_q, we find the ratio\nbetween the mixed condensate and the quark condensate, m_0^2 = g<\\bar{q} sigma\nG q> / <\\bar{q}q> \\simeq 2.5 GeV^2 at the lattice scale of 1/a \\simeq 2 GeV in\nthe chiral limit. The large value of the mixed condensate suggests its\nimportance in the operator product expansions in QCD.",
        "positive": "Volume Dependence of Spectral Weights for Unstable Particles in a\n  Solvable Model: Volume dependence of the spectral weight is usually used as a simple criteria\nto distinguish single-particle states from multi-particle states in lattice QCD\ncalculations. Within a solvable model, the Lee model, we show that this\ncriteria is in principle only valid for a stable particle or a narrow\nresonance. If the resonance being studied is broad, then the volume dependence\nof the corresponding spectral weight resembles that of a multi-particle state\ninstead of a single-particle one. For an unstable $V$-particle in the Lee\nmodel, the transition from single-particle to multi-particle volume dependence\nis governed by the ratio of its physical width to the typical level spacing in\nthe finite volume. We estimate this ratio for practical lattice QCD simulations\nand find that, for most cases, the resonance studied in lattice QCD simulations\nstill resembles the single particle behavior."
    },
    {
        "anchor": "Investigating quark confinement from the viewpoint of lattice\n  gauge-scalar models: In this talk, first, we show that the color $N$-dependent area law falloffs\nof the double-winding Wilson loop averages for the $SU(N)$ lattice gauge model\nare reproduced from the $Z_N$ lattice Abelian gauge model due to the center\ngroup dominance in quark confinement. Next, we discuss lattice gauge-scalar\nmodels which allow analytic continuation for gauge invariant operators between\nconfinement region and Higgs region. Applying the cluster expansion, we try to\nunderstand non-trivial contribution from scalar field in quark confinement\nmechanism. In order to understand quark confinement further, moreover, we study\ndouble-winding Wilson loop averages in the analytical region on the phase\ndiagram.",
        "positive": "Testing Proposals for the Yang-Mills Vacuum Wavefunctional by\n  Measurement of the Vacuum: We review a method, suggested many years ago, to numerically measure the\nrelative amplitudes of the true Yang-Mills vacuum wavefunctional in a finite\nset of lattice-regulated field configurations. The technique is applied in 2+1\ndimensions to sets of abelian plane wave configurations of varying amplitude\nand wavelength, and sets of non-abelian constant configurations. The results\nare compared to the predictions of several proposed versions of the Yang-Mills\nvacuum wavefunctional that have appeared in the literature. These include (i) a\nsuggestion in temporal gauge due to Greensite and Olejnik; (ii) the \"new\nvariables\" wavefunction put forward by Karabali, Kim, and Nair; (iii) a hybrid\nproposal combining features of the temporal gauge and new variables\nwavefunctionals; and (iv) Coulomb gauge wavefunctionals developed by Reinhardt\nand co-workers, and by Szczepaniak and co-workers. We find that wavefunctionals\nwhich simplify to a \"dimensional reduction\" form at large scales, i.e. which\nhave the form of a probability distribution for two-dimensional lattice gauge\ntheory, when evaluated on long-wavelength configurations, have the optimal\nagreement with the data."
    },
    {
        "anchor": "Influence of topology on the scale setting: Recently a new method to set the scale in lattice gauge theories, based on\nthe gradient flow generated by the Wilson action, has been proposed, and the\nsystematic errors of the new scales t0 and w0 have been investigated by various\ngroups. The Wilson flow provides also an interesting alternative smoothing\nprocedure in particular useful for the measurement of the topological charge as\na pure gluonic observable. We show the viability of this method for N=1\nsupersymmetric Yang-Mills theory by analysing the configurations produced by\nthe DESY-Muenster collaboration. For increasing flow time the topological\ncharge quickly approaches near-integer values. The topological susceptibility\nhas been measured for different fermion masses and its value is observed to\napproach zero in the chiral limit. Finally, the relation between the scale\ndefined by the Wilson flow and the topological charge has been investigated,\ndemonstrating a correlation between these two quantities.",
        "positive": "Local coherence and deflation of the low quark modes in lattice QCD: The spontaneous breaking of chiral symmetry in QCD is known to be linked to a\nnon-zero density of eigenvalues of the massless Dirac operator near the origin.\nNumerical studies of two-flavour QCD now suggest that the low quark modes are\nlocally coherent to a certain extent. As a consequence, the modes can be\nsimultaneously deflated, using local projectors, with a total computational\neffort proportional to the lattice volume (rather than its square). Deflation\nhas potentially many uses in lattice QCD. The technique is here worked out for\nthe case of quark propagator calculations, where large speed-up factors and a\nflat scaling behaviour with respect to the quark mass are achieved."
    },
    {
        "anchor": "Decomposition of the SU(2) gauge field in the Maximal Abelian gauge: We study decomposition of $SU(2)$ gauge field into monopole and monopoleless\ncomponents. After fixing the Maximal Abelian gauge in $SU(2)$ lattice gauge\ntheory we decompose the nonabelian gauge field into the Abelian field created\nby monopoles and the modified nonabelian field with monopoles removed. We then\ncalculate respective static potentialis and show that the potential due to the\nmodified nonabelian field is nonconfining while, as is well known, the Abelian\nfield produces linear potential. We further find that the sum of these\npotentials approximates the nonabelian static potential with good precision at\nall distances considered. We conclude that at large distances the monopole\nfield potential describes the classical energy of the hadronic string while the\nstatic potential due to the modified nonabelian field describes the string\nfluctuations energy.",
        "positive": "A Gauge Theory of Wilson Lines as a Dimensionally Reduced Model of QCD_3: We analyze a two dimensional SU(3) gauge model of Wilson lines as a\ndimensionally reduced model of high temperature QCD_3. In contrast to\nperturbative dimensional reduction it has an explicit global Z(3) symmetry in\nthe action. The phase diagram of the model is studied in the space of two free\nparameters used to describe the self interaction of the Wilson lines. In\naddition to the confinement-deconfinement transition, the model also exhibits a\nnew Z(3)-breaking phase. These findings are obtained by numerical simulations,\nand supported by a perturbative calculation to one loop. A screening mass from\nPolyakov loop correlations is calculated numerically. It matches the known\nQCD_3 mass in a domain of parameters belonging to the normal deconfined phase."
    },
    {
        "anchor": "Renormalization of local quark-bilinear operators for Nf=3 flavors of\n  SLiNC fermions: The renormalization factors of local quark-bilinear operators are computed\nnon-perturbatively for $N_f=3$ flavors of SLiNC fermions, with emphasis on the\nvarious procedures for the chiral and continuum extrapolations. The simulations\nare performed at a lattice spacing $a=0.074$ fm, and for five values of the\npion mass in the range of 290-465 MeV, allowing a safe and stable chiral\nextrapolation. Emphasis is given in the subtraction of the well-known pion pole\nwhich affects the renormalization factor of the pseudoscalar current. We also\ncompute the inverse propagator and the Green's functions of the local bilinears\nto one loop in perturbation theory. We investigate lattice artifacts by\ncomputing them perturbatively to second order as well as to all orders in the\nlattice spacing. The renormalization conditions are defined in the RI$'$-MOM\nscheme, for both the perturbative and non-perturbative results. The\nrenormalization factors, obtained at different values of the renormalization\nscale, are translated to the ${\\bar{\\rm MS}}$ scheme and are evolved\nperturbatively to 2 GeV. Any residual dependence on the initial renormalization\nscale is eliminated by an extrapolation to the continuum limit. We also study\nthe various sources of systematic errors.\n  Particular care is taken in correcting the non-perturbative estimates by\nsubtracting lattice artifacts computed to one loop perturbation theory using\nthe same action. We test two different methods, by subtracting either the\n${\\cal O}(g^2\\,a^2)$ contributions, or the complete (all orders in $a$)\none-loop lattice artifacts.",
        "positive": "Another approach to local cohomology problem in abelian lattice gauge\n  theories: A new technique is proposed to classify a topological field in abelian\nlattice gauge theories. We perform the classification by regarding the\ntopological field as a local composite field of the gauge field tensor instead\nof the vector potential associated to an admissible gauge field. Our method\nreproduces the result obtained by the ordinary method in the infinite\nfour-dimensional lattice and can be extended to arbitrary higher dimensions. It\nalso works in the direct cohomological analysis on a finite lattice."
    },
    {
        "anchor": "The intrinsic strangeness and charm of the nucleon using improved\n  staggered fermions: We calculate the intrinsic strangeness of the nucleon, <N|ss|N> - <0|ss|0>,\nusing the MILC library of improved staggered gauge configurations using the\nAsqtad and HISQ actions. Additionally, we present a preliminary calculation of\nthe intrinsic charm of the nucleon using the HISQ action with dynamical charm.\nThe calculation is done with a method which incorporates features of both\ncommonly-used methods, the direct evaluation of the three-point function and\nthe application of the Feynman- Hellman theorem. We present an improvement on\nthis method that further reduces the statistical error, and check the result\nfrom this hybrid method against the other two methods and find that they are\nconsistent. The values for <N|ss|N> and <N|cc|N> found here, together with\nperturbative results for heavy quarks, show that dark matter scattering through\nHiggs-like exchange receives roughly equal contributions from all heavy quark\nflavors.",
        "positive": "Axial and pseudoscalar form-factors of the Delta^+(1232): We present first results on the axial and pseudoscalar $\\Delta$ form factors.\nThe analysis is carried out in the quenched approximation where statistical\nerrors are small and the lattice set-up can be investigated relatively quickly.\nWe also present an analysis with a hybrid action using staggered sea quarks and\ndomain-wall valence fermions."
    },
    {
        "anchor": "The topological structures in strongly coupled QGP with chiral fermions\n  on the lattice: The nature of chiral phase transition for two flavor QCD is an interesting\nbut unresolved problem. One of the most intriguing issues is whether or not the\nanomalous U(1) symmetry in the flavor sector is effectively restored along with\nthe chiral symmetry. This may determine the universality class of the chiral\nphase transition. Since the physics near the chiral phase transition is\nessentially non-perturbative, we employ first principles lattice techniques to\naddress this issue. We use overlap fermions, which have exact chiral symmetry\non the lattice, to probe the anomalous U(1) symmetry violation of 2+1 flavor\ndynamical QCD configurations with domain wall fermions. The latter also\noptimally preserves chiral and flavor symmetries on the lattice, since it is\nknown that the remnant chiral symmetry of the light quarks influences the\nscaling of the chiral condensate in the crossover transition region. We observe\nthat the anomalous U(1) is not effectively restored in the chiral crossover\nregion. We perform a systematic study of the finite size and cut-off effects\nsince the signals of U(1) violation are sensitive to it. We also provide a\nglimpse of the microscopic topological structures of the QCD medium that are\nresponsible for the strongly interacting nature of the quark gluon plasma\nphase. We study the effect of these microscopic constituents through our first\ncalculations for the topological susceptibility of QCD at finite temperature,\nwhich could be a crucial input for the equation of state for anomalous\nhydrodynamics.",
        "positive": "Quasi particles in hot QCD: We show at very high temperature how the behaviour of the spatial 't Hooft\nloop in the QCD plasma is simply related to the chromo electric flux of the\ngluons. This simple picture is vindicated by a systematic quasi classical\napproach. The spatial Wilson loop 's behaviour is computed by a similar nearly\nfree plasma of magnetic quasiparticles. This model predicts unambiguously\nratios of multiply charged Wilson loops. Recent simulations confirm these\npredictions accurately."
    },
    {
        "anchor": "Self-dual U(1) lattice field theory with a $\u03b8$-term: We study U(1) gauge theories with a modified Villain action. Such theories\ncan naturally be coupled to electric and magnetic matter, and display exact\nelectric-magnetic duality. In their simplest formulation without a\n$\\theta$-term, such theories are ultra-local. We extend the discussion to U(1)\ngauge theories with $\\theta$-terms, such that $\\theta$ periodicity is exact for\na free theory, and show that imposing electric-magnetic duality results in a\nlocal, but not ultra-local lattice action, which is reminiscent of the\nL\\\"uscher construction of axial-symmetry preserving fermions in 4d. We discuss\nthe coupling to electric and magnetic matter as well as to dyons. For dyonic\nmatter the electric-magnetic duality and shifts of the $\\theta$-angle by $2\\pi$\ntogether generate an SL$(2,\\mathbb Z)$ duality group of transformations, just\nlike in the continuum. We finally illustrate how the SL$(2,\\mathbb Z)$ duality\nmay be used to explore theories at finite $\\theta$ without a sign problem.",
        "positive": "String tension and monopoles in $T \\neq 0$ SU(2) QCD: Monopole and photon contributions to abelian Wilson loops are calculated\nusing Monte-Carlo simulations of finite-temperature $SU(2)$ QCD in the\nmaximally abelian gauge. Long monopole loops alone are responsible for the\nbehavior of the string tension in the confinement phase up to the critical\n$\\beta_c$. Short monopole loops and photons do not contribute to the string\ntension. The abelian and the monopole spacial string tensions (both of which\nagree with the normal ones for $\\beta < \\beta_c$) show a $g^{4}(T) T^2$ scaling\nbehavior in the deconfinement phase. The abelian spacial string tension is in\nagreement with the full one even in the deconfinement phase."
    },
    {
        "anchor": "Berezinskii-Kosterlitz-Thouless transitions in two-dimensional lattice\n  SO($N_c$) gauge theories with two scalar flavors: We study the phase diagram and critical behavior of a two-dimensional lattice\nSO($N_c$) gauge theory ($N_c \\ge 3$) with two scalar flavors, obtained by\npartially gauging a maximally O($2N_c$) symmetric scalar model. The model is\ninvariant under local SO($N_c$) and global O(2) transformations. We show that,\nfor any $N_c \\ge 3$, it undergoes finite-temperature\nBerezinskii-Kosterlitz-Thouless (BKT) transitions, associated with the global\nAbelian O(2) symmetry. The transition separates a high-temperature disordered\nphase from a low-temperature spin-wave phase where correlations decay\nalgebraically (quasi-long range order). The critical properties at the\nfinite-temperature BKT transition and in the low-temperature spin-wave phase\nare determined by means of a finite-size scaling analysis of Monte Carlo data.",
        "positive": "Progress in the calculation of purely leptonic $D_{(s)}$ -- decay\n  constants from lattice QCD: We review recent progress in the calculation of the decay constants $f_{D}$\nand $f_{D_s}$ from lattice QCD. We focus particularly on simulations with\n$N_f=2+1$ and $N_f=2+1+1$ and simulations with close to physical light quark\nmasses."
    },
    {
        "anchor": "I=2 Pion scattering length with improved actions on anisotropic lattices: $\\pi\\pi$ scattering length in the I=2 channel is calculated within quenched\napproximation using improved gauge and improved Wilson fermion actions on\nanisotropic lattices. The results are extrapolated towards the chiral, infinite\nvolume and continuum limit. This result improves our previous result on the\nscattering length. In the chiral, infinite volume and continuum limit, we\nobtain $a^{(2)}_0m_\\pi=-0.0467(45)$, which is consistent with the result from\nChiral Perturbation Theory, the experiment and results from other lattice\ncalculations.",
        "positive": "Relation between chiral symmetry breaking and confinement in YM-theories: Spectral sums of the Dirac-Wilson operator and their relation to the Polyakov\nloop are thoroughly investigated. The approach by Gattringer is generalized to\nmode sums which reconstruct the Polyakov loop locally. This opens the\npossibility to study the mode sum approximation to the Polyakov loop\ncorrelator. The approach is re-derived for the ab initio continuum formulation\nof Yang-Mills theories, and the convergence of the mode sum is studied in\ndetail. The mode sums are then explicitly calculated for the Schwinger model\nand SU(2) gauge theory in a homogeneous background field. Using SU(2) lattice\ngauge theory, the IR dominated mode sums are considered and the mode sum\napproximation to the static quark anti-quark potential is obtained numerically.\nWe find a good agreement between the mode sum approximation and the static\npotential at large distances for the confinement and the high temperature\nplasma phase."
    },
    {
        "anchor": "QCD Thermodynamics on the Lattice: Recent Results: I give a brief introduction to the goals, challenges, and technical\ndifficulties of lattice QCD thermodynamics and present some recent results from\nthe HotQCD collaboration for the crossover temperature, equation of state, and\nother observables.",
        "positive": "Universality of Mixed Action Extrapolation Formulae: Mixed action theories with chirally symmetric valence fermions exhibit very\ndesirable features both at the level of the lattice calculations as well as in\nthe construction and implementation of the low energy mixed action effective\nfield theory. In this work we show that when such a mixed action effective\nfield theory is projected onto the valence sector, both the Lagrangian and the\nextrapolation formulae become universal in form through next to leading order,\nfor all variants of discretization methods used for the sea fermions. Our\nconclusion relies on the chiral nature of the valence quarks. The result\nimplies that for all sea quark methods which are in the same universality class\nas QCD, the numerical values of the physical coefficients in the various mixed\naction chiral Lagrangians will be the same up to lattice spacing dependent\ncorrections. This allows us to construct a prescription to determine the mixed\naction extrapolation formulae for a large class of hadronic correlation\nfunctions computed in partially quenched chiral perturbation theory at the\none-loop level. For specific examples, we apply this prescription to the\nnucleon twist--2 matrix elements and the nucleon--nucleon system. In addition,\nwe determine the mixed action extrapolation formula for the neutron EDM as this\nprovides a nice example of a theta-dependent observable; these observables are\nexceptions to our prescription."
    },
    {
        "anchor": "Electroweak interactions and dark baryons in the sextet BSM model with a\n  composite Higgs particle: The Electroweak interactions of a strongly coupled gauge theory are discussed\nwith outlook beyond the Standard Model (BSM) under global and gauge anomaly\nconstraints. The theory is built on a minimal massless fermion doublet of the\nSU(2) BSM flavor group (bsm-flavor) with a confining gauge force at the TeV\nscale in the two-index symmetric (sextet) representation of the BSM SU(3) color\ngauge group (bsm-color). The intriguing possibility of near-conformal sextet\ngauge dynamics could lead to the minimal realization of the composite Higgs\nmechanism with a light $0^{++}$ scalar, far separated from strongly coupled\nresonances of the confining gauge force in the 2-3 TeV range, distinct from\nHiggsless Technicolor. In previous publications we have presented results for\nthe meson spectrum of the theory, including the light composite scalar, perhaps\nthe emergent Higgs impostor. Here we discuss the critically important role of\nthe baryon spectrum in the sextet model investigating its compatibility with\nwhat we know about thermal evolution of the early Universe including its\ngalactic and terrestrial relics. For an important application, we report the\nfirst numerical results on the baryon spectrum of this theory from\nnon-perturbative lattice simulations with baryon correlators in the staggered\nfermion implementation of the strongly coupled gauge sector. The quantum\nnumbers of composite baryons and their spectroscopy from lattice simulations\nare required inputs for exploring dark matter contributions of the sextet BSM\nmodel, as outlined for future work.",
        "positive": "Appearence of Mother Universe and Singular Vertices in Random Geometries: We discuss a general mechanism that drives the phase transition in the\ncanonical ensemble in models of random geometries. As an example we consider a\nsolvable model of branched polymers where the transition leading from tree- to\nbush-like polymers relies on the occurrence of vertices with a large number of\nbranches. The source of this transition is a combination of the constraint on\nthe total number of branches in the canonical ensemble and a nonlinear\none-vertex action. We argue that exactly the same mechanism, which we call\nconstrained mean-field, plays the crucial role in the phase transition in 4d\nsimplicial gravity and, when applied to the effective one-vertex action,\nexplains the occurrence of both the mother universe and singular vertices at\nthe transition point when the system enters the crumpled phase."
    },
    {
        "anchor": "Even parity excitations of the nucleon in lattice QCD: We study the spectrum of the even parity excitations of the nucleon in\nquenched lattice QCD. We extend our earlier analysis by including an expanded\nbasis of nucleon interpolating fields, increasing the physical size of the\nlattice, including more configurations to enhance statistics and probing closer\nto the chiral limit. With a review of world lattice data, we conclude that\nthere is little evidence of the Roper resonance in quenched lattice QCD.",
        "positive": "Finite size phase transitions in QCD with adjoint fermions: We perform a lattice investigation of QCD with three colors and 2 flavors of\nDirac (staggered) fermions in the adjoint representation, defined on a 4d space\nwith one spatial dimension compactified, and study the phase structure of the\ntheory as a function of the size Lc of the compactified dimension. We show that\nfour different phases take place, corresponding to different realizations of\ncenter symmetry: two center symmetric phases, for large or small values of Lc,\nseparated by two phases in which center symmetry is broken in two different\nways; the dependence of these results on the quark mass is discussed. We study\nalso chiral properties and how they are affected by the different realizations\nof center symmetry; chiral symmetry, in particular, stays spontaneously broken\nat the phase transitions and may be restored at much lower values of the\ncompactification radius. Our results could be relevant to a recently proposed\nconjecture of volume indepedence of QCD with adjoint fermions in the large Nc\nlimit."
    },
    {
        "anchor": "Nonperturbative $O(a)$ improvement of the Wilson quark action with the\n  RG-improved gauge action using the Schr\u00f6dinger functional method: We perform a nonperturbative determination of the $O(a)$-improvement\ncoefficient $c_{\\rm SW}$ and the critical hopping parameter $\\kappa_c$ for\n$N_f$=3, 2, 0 flavor QCD with the RG-improved gauge action using the\nSchr\\\"odinger functional method. In order to interpolate $c_{\\rm SW}$ and\n$\\kappa_c$ as a function of the bare coupling, a wide range of $\\beta$ from the\nweak coupling region to the moderately strong coupling points used in\nlarge-scale simulations is studied. Corrections at finite lattice size of\n$O(a/L)$ turned out to be large for the RG-improved gauge action, and hence we\nmake the determination at a size fixed in physical units using a modified\nimprovement condition. This enables us to avoid $O(a)$ scaling violations which\nwould remain in physical observables if $c_{\\rm SW}$ determined for a fixed\nlattice size $L/a$ is used in numerical simulations.",
        "positive": "Inclusion of isospin breaking effects in lattice simulations: Isospin symmetry is explicitly broken in the Standard Model by the mass and\nelectric charge of the up and down quarks. These effects represent a\nperturbation of hadronic amplitudes at the percent level. Although these\ncontributions are small, they play a crucial role in hadronic and nuclear\nphysics. Moreover, as lattice computations are becoming increasingly precise,\nit is becoming more and more important to include these effects in numerical\nsimulations. We summarize here how to properly define QCD and QED on a finite\nand discrete space-time so that isospin corrections to hadronic observables can\nbe computed ab-initio and we review the main results on the isospin corrections\nto the hadron spectrum. We mainly focus on the recent work going beyond the\nelectro-quenched approximation."
    },
    {
        "anchor": "Simple ansatz for the lattice fermion determinant: An ansatz for the fermion vacuum functional on a lattice is proposed. It is\nproved to reproduce correct continuum limit for convergent diagrams of any\nfinite order in smooth external fields, as well as consistent chiral anomalies,\nand ensures gauge invariance of the absolute value of the functional at any\nlattice spacing. The ansatz corresponds to a certain non-local fermion action\nhaving global chiral invariance. Problems caused by non-smooth gauge fields are\ndiscussed.",
        "positive": "The XY Model on a Dynamical Random Lattice: We study the XY model on a lattice with fluctuating connectivity. The\nexpectation is that at an appropriate critical point such a system corresponds\nto a compactified boson coupled to 2d quantum gravity. Our simulations focus,\nin particular, on the important topological features of the system. The results\nlend strong support to the two phase structure predicted on the basis of\nanalytical calculations. A careful finite size scaling analysis yields\nestimates for the critical exponents in the low temperature phase."
    },
    {
        "anchor": "The scaling dimension of low lying Dirac eigenmodes and of the\n  topological charge density: As a quantitative measure of localization, the inverse participation ratio of\nlow lying Dirac eigenmodes and topological charge density is calculated on\nquenched lattices over a wide range of lattice spacings and volumes. Since\ndifferent topological objects (instantons, vortices, monopoles, and artifacts)\nhave different co-dimension, scaling analysis provides information on the\namount of each present and their correlation with the localization of low lying\neigenmodes.",
        "positive": "Towards extracting the timelike pion form factor on CLS 2-flavour\n  ensembles: Results are presented from an ongoing study of the $\\rho$ resonance. We use\nthe distillation approach in order to create correlator matrices involving\n$\\rho$ and $\\pi\\pi$ interpolators. The study is done in a centre-of-mass frame\nand several moving frames. We are able to extract energy levels by solving the\nGEVP of those correlator matrices. The initial exploratory study is being done\non a CLS 2-flavour lattice with a pion mass of $451$ $\\mathrm{MeV}$ using\n$\\mathcal{O}(a)$ improved Wilson fermions. One aim of this work is to extract\nthe timelike pion form factor after applying the L\\\"uscher formalism. We also\nplan to integrate this study with the existing Mainz programme for the\ncalculation of the hadronic vacuum polarization contribution to the muon $g-2$\nand will extend our study to lower pion masses and larger lattices in the\nfuture, including ensembles with $2+1$ flavours."
    },
    {
        "anchor": "Flavored aspects of QCD thermodynamics from Lattice QCD: We discuss recent progress in lattice QCD studies on various aspects\ninvolving strange quarks. Appropriate combinations of conserved net strange and\nnet charm fluctuations and their correlations with other conserved charges\nprovide evidence that in the hadronic phase so far unobserved hadrons\ncontribute to the thermodynamics and need to be included in hadron resonance\ngas models. In the strange sector this leads to significant reductions of the\nchemical freeze-out temperature of strange hadrons. In this context, a\ndiscussion of data from heavy-ion collisions at SPS, RHIC and LHC on the\nchemical freeze-out of hadronic species is presented. It can be observed that a\ndescription of the thermodynamics of open strange and open charm degrees of\nfreedom in terms of an uncorrelated hadron gas is valid only up to temperatures\nclose to the chiral crossover temperature. This suggests that in addition to\nlight and strange hadrons also open charm hadrons start to dissolve already\nclose to the chiral crossover. Further indications that open charm mesons start\nto melt in the vicinity of $T_c$ is obtained from an analysis of screening\nmasses, while in the charmonium sector these screening masses show a behavior\ncompatible with a sequential melting pattern. At the end of this chapter we\nwill discuss some basics of lattice gauge theory and Monte Carlo calculations.\nThis will provide the required knowledge for performing first lattice\ncalculations for SU(3) pure gauge theory and studying thermodynamic quantities\nin the exercises of this chapter.",
        "positive": "Embedded Topological Defects in Electroweak Theory: From Percolating\n  Networks to Sphalerons: New defects (Z-vortices and Nambu monopoles) are found to become\nthermodynamically relevant for the broken phase near to the (weakly first\norder) electroweak phase transition, and below the crossover for higher Higgs\nmass. The symmetric phase is characterized by vortex condensation\n(percolation). The percolation transition persists in the crossover region. The\nquasiclassical nature of the vortices is supported by correlations with Higgs\nfield and gauge field energy. Sphalerons are shown to be related to monopolium\nbound states."
    },
    {
        "anchor": "Structure of the Pion from Full Lattice QCD: Moments of generalised parton distributions can be related to off-forward\nmatrix elements of local operators. We calculate a few of the leading twist\nmatrix elements for the pion on the lattice. The simulations are performed\nusing two flavours of dynamical fermions and a range of pion masses from 550 to\n1090 MeV. Our lattice spacings and spatial volumes lie in the range 0.07-0.12\nfm and (1.6-2.2 fm)^3, respectively. Key features of our investigation are the\nuse of O(a) improved Wilson fermions and non-perturbative renormalisation. We\npresent first results for the two lowest moments of the generalised parton\ndistributions of the pion and compare the pion electromagnetic form factor F_pi\nto experimental data. Good agreement is found between lattice data and\nexperiment.",
        "positive": "SU(3) gauge theory with 12 flavours in a twisted box: We present preliminary result for the step-scaling study of the coupling\nconstant with the Yang-Mills gradient flow, in the twelve-favour SU(3) gauge\ntheory. In this work, the lattice simulation is performed using unimproved\nstaggered fermions and the Wilson plaquette gauge action, from which the\ngradient flow is also implemented. Imposing twisted boundary condition a'la\nt'Hooft and Parisi, our calculation is performed at zero fermion mass. The\nrenormalised coupling constant is extracted via the computation of the energy\ndensity. In order to examine the reliability of the continuum extrapolation, we\ninvestigate this coupling constant using two different lattice discretisations.\nOur result shows that in order to control the systematic effects in the\ncontinuum extrapolation, it is necessary to implement a large enough\ngradient-flow time. In the current calculation, the gauge-field averaging\nradius corresponding to the flow time has to be as large as 40% of the lattice\nsize."
    },
    {
        "anchor": "Flavour singlet pseudoscalar masses in N_f = 2 QCD: We perform a lattice mass analysis in the flavour singlet pseudoscalar\nchannel on the SESAM and TXL full QCD vacuum configurations, with 2 active\nflavours of dynamical Wilson fermions at beta = 5.6. At our inverse lattice\nspacing, a^-1 = 2.3 GeV, we retrieve by a chiral extrapolation to the physical\nlight quark masses the value m_eta' = 3.7(+8)(-4) m_pi. A crude extrapolation\nfrom (N_f = 3) phenomenology would suggest m_eta' \\approx 5.1 m_pi for N_f = 2\nQCD. we verify that the mass gap between the singlet state eta' and the pi\nflavour triplt state is due to gauge configurations with non-trivial topology.",
        "positive": "Thermodynamics of the strongly interacting gluon plasma in the large-N\n  limit: We report on our recent study of equilibrium thermodynamic observables in\nSU(N) gauge theories with N=3, 4, 5, 6 and 8 colors at temperatures T in the\nrange from 0.8 T_c to 3.4 T_c (where T_c denotes the critical deconfinement\ntemperature). The results, which show a very weak dependence on the number of\ncolors, are compared with gauge/gravity models of the QCD plasma, including the\nimproved holographic QCD model proposed by Kiritsis and collaborators, and with\nthe supergravity prediction for the entropy density deficit. Furthermore, we\ninvestigate the possibility that the trace anomaly may receive contributions\nproportional to T^2 at temperatures close to T_c. Finally, we present the\nextrapolated results for the pressure, trace anomaly, energy and entropy\ndensities in the limit for N going to infinity."
    },
    {
        "anchor": "High statistics lattice study of stress tensor correlators in pure\n  $SU(3)$ gauge theory: We compute the Euclidean correlators of the stress tensor in pure $SU(3)$\nYang-Mills theory at finite temperature at zero and finite spatial momenta with\nlattice simulations. We perform continuum extrapolations using\n$N_\\tau=10,12,16,20$ lattices with renormalized anisotropy 2. We use these\ncorrelators to estimate the shear viscosity of the gluon plasma in the\ndeconfined phase. For $T=1.5T_c$ we obtain $\\eta/s=0.17(2)$.",
        "positive": "Gauge Invariant Monopoles in SU(2) Gluodynamics: We introduce a gauge invariant topological definition of monopole charge in\npure SU(2) gluodynamics. The non-trivial topology is provided by hedgehog\nconfigurations of the non-Abelian field strength tensor on the two-sphere\nsurrounding the monopole. It is shown that this definition can be formulated\nentirely in terms of Wilson loops which makes the gauge invariance manifest.\nMoreover, it counts correctly the monopole charge in case of spontaneously\nbroken gauge symmetry and of pure Abelian gauge fields."
    },
    {
        "anchor": "Monopole Condensation and Confinement in SU(2) QCD (1): An effective monopole action is derived from vacuum configurations after\nabelian projection in the maximally abelian gauge in $SU(2)$ QCD. Entropy\ndominance over energy of monopole loops is seen on the renormalized lattice\nwith the spacing $b>b_c\\simeq 5.2\\times10^{-3} \\Lambda_L^{-1}$ when the\nphysical volume of the system is large enough. QCD confinement may be\ninterpreted as the (dual) Meissner effect due to the monopole condensation.",
        "positive": "A Wilson-Yukawa model with undoubled chiral fermions in 2D: We consider the fermion spectrum in the strong coupling vortex phase of a\nlattice fermion-scalar model with a global $U(1)_L\\times U(1)_R$, in 2D, in the\ncontext of a recently proposed two-cutoff lattice formulation. The fermion\ndoublers are made massive by a strong Wilson-Yukawa coupling, but in contrast\nwith the standard formulation of these models, in which the light fermion\nspectrum was found to be massive and vectorlike, we find massless undoubled\nfermions with chiral quantum numbers at finite lattice spacing. When the global\nsymmetry is gauged, this model is expected to give rise to a chiral gauge\ntheory."
    },
    {
        "anchor": "Exotic Phases of a Higgs-Yukawa Model with Reduced Staggered Fermions: We investigate the phase structure of a four dimensional SO(4) invariant\nlattice Higgs-Yukawa model comprising four reduced staggered fermions\ninteracting with a real scalar field. The fermions belong to the fundamental\nrepresentation of the symmetry group while the three scalar field components\ntransform in the self-dual representation of SO(4). We explore the phase\ndiagram and find evidence of a continuous transition between a phase where the\nfermions are massless to one where the fermions acquire mass. This transition\nis not associated with symmetry breaking and there is no obvious local order\nparameter.",
        "positive": "The shape of the static potential with dynamical fermions: We present the analysis of the static potential extracted from Wilson loops\nmeasured on CLS ensembles generated with Wilson gauge action and Nf=2 flavors\nof O(a) improved Wilson quarks at three different lattice spacings and a range\nof quark masses. The shape of the static potential at distances well below the\nstring breaking region is studied in terms of renormalized couplings derived\nfrom the static force and its derivative. We comment on the (im)possibility of\nextracting the Lambda parameter at our smallest lattice spacing a=0.05 fm.\nFinally we give an update on the scale determination through r0."
    },
    {
        "anchor": "Looking for $U(1)_A$ Restoration in Hot QCD with Domain Wall Fermions: The effects of the axial anomaly are suppressed at high temperatures due to\nscreening effects in the quark-gluon plasma. If the suppression is nearly\ncomplete close to the chiral transition temperature, this can have consequences\nfor the nature of the phase transition. The use of a chiral action such as\nDomain Wall Fermions allows us to gain a deeper insight into the issue. Our\nlattice sizes were $16^3\\times 8\\times L_s$, with $L_s=32$ or 48, and our pion\nmass was approximately 200 MeV. We found that $U(1)_A$ stayed broken above the\nchiral transition. However the breaking was found to be due to topologically\nnontrivial configurations which raises the question as to whether it persists\nin the thermodynamic limit. We also present results for the eigenvalue density\nof the Dirac operator. It is seen that although the density decreases\ndramatically across the chiral transition temperature, $U(1)_A$ still remains\nbroken at our current volume and quark mass due to the presence of zero modes.",
        "positive": "Dual Meissner effect and non-Abelian dual superconductivity in SU(3)\n  Yang-Mills theory: The dual Meissner effect is the promising mechanism for quark confinement. We\nhave proposed a new formulation of SU(N) Yang-Mills (YM) theory on a lattice,\nwhich can extract the dominant mode for quark confinement in the gauge\nindependent manner. In the last lattice conference, we have demonstrated by\nmeasuring the string tension from the Wilson loop average in the SU(3) YM\ntheory that the restricted non-Abelian variable and the extracted non-Abelian\nmagnetic monopoles play the dominant role in confinement of fundamental quarks\n(dominance in the string tension), in marked contrast to the Abelian\nprojection.\n  In this talk, we focus on the dual Meissner effect in SU(3) YM theory, which\nis examined by measuring the distribution of chromo-electric field strength\ncreated by a static quark-antiquark pair. We apply the new lattice formulation,\nand examine whether or not the non-Abelian dual superconductivity claimed by us\nis indeed a mechanism of quark confinement. We present a preliminary result of\nthe direct evidence for the non-abelian dual Meissner effect, that is to say,\nrestricted U(2)-field part of the flux tube plays the dominant role in the\nquark-antiquark potential."
    },
    {
        "anchor": "The spectrum of lattice QCD with staggered fermions at strong coupling: Using 4 flavors of staggered fermions at infinite gauge coupling, we compare\nvarious analytic results for the hadron spectrum with exact Monte Carlo\nsimulations. Agreement with Ref. \\cite{Martin_etal} is very good, at the level\nof a few percent.\n  Our results give credence to a discrepancy between the baryon mass and the\ncritical chemical potential, for which baryons fill the lattice at zero\ntemperature and infinite gauge coupling. Independent determinations of the\nlatter set it at about 30% less than the baryon mass. One possible explanation\nis that the nuclear attraction becomes strong at infinite gauge coupling.",
        "positive": "The Difference between the Longitudinal and Transverse Gluon Propagators\n  as an Indicator of the Postconfinement Domain: We study numerically the dependence of the difference between the\nlongitudinal and transverse gluon propagators, $\\Delta=D_L-D_T$, on the\nmomentum and temperature at $T\\gtrsim T_c$ both in SU(2) and SU(3)\ngluodynamics. It is found that the integral of $\\Delta$ with respect to the\n3-momentum is sensitive only to infrared dynamics and shows a substantial\ncorrelation with the Polyakov loop. At $T=T_p\\sim 1.2 T_c$ it changes sign\ngiving some evidence that $T_p$ can serve as a boundary of the postconfinement\ndomain."
    },
    {
        "anchor": "Lattice QCD computation of the colour fields for the static hybrid\n  quark-gluon-antiquark system, and microscopic study of the Casimir scaling: The chromoelectric and chromomagnetic fields, created by a static\ngluon-quark-antiquark system, are computed in quenched SU(3) lattice QCD, in a\n$24^3\\times 48$ lattice at $\\beta=6.2$ and $a=0.07261(85) fm$. We compute the\nhybrid Wilson Loop with two spatial geometries, one with a U shape and another\nwith an L shape. The particular cases of the two gluon glueball and\nquark-antiquark are also studied, and the Casimir scaling is investigated in a\nmicroscopic perspective. This microscopic study of the colour fields is\nrelevant to understand the structure of hadrons, in particular of the hybrid\nexcitation of mesons. This also contributes to understand confinement with flux\ntubes and to discriminate between the models of fundamental versus adjoint\nconfining strings, analogous to type-II and type-I superconductivity.",
        "positive": "Study of the anomalous magnetic moment of the muon computed from the\n  Adler function: We compute the Adler function on the lattice from vacuum polarization data\nwith twisted boundary conditions using numerical derivatives. The study is\nbased on CLS ensembles with two flavours of $O(a)$ improved Wilson fermions. We\nextrapolate the lattice data for the Adler function to the continuum limit and\nto the physical pion mass and analyze its dependence on the momentum transfer.\nWe discuss the application of this method to the extraction of the $u,d$\ncontribution to $a_\\mu^{\\mathrm{HLO}}$."
    },
    {
        "anchor": "Forces between static-light mesons: The isospin, spin and parity dependent potential of a pair of static-light\nmesons is computed using Wilson twisted mass lattice QCD with two flavors of\ndegenerate dynamical quarks. From the results a simple rule can be deduced\nstating, which isospin, spin and parity combinations correspond to attractive\nand which to repulsive forces.",
        "positive": "Radiative contribution to the composite-Higgs potential in a\n  two-representation lattice model: Working in a two-representation lattice gauge theory that is close to a\ncomposite Higgs model, we calculate the low-energy constant CLR which controls\nthe contribution of the electroweak gauge bosons to the Higgs potential. In\nQCD, the corresponding low-energy constant governs the mass splitting of the\npion multiplet. Taking the continuum and chiral limits, we find that CLR, in\nunits of the pseudoscalar decay constant, is roughly of the same size as its\nQCD counterpart."
    },
    {
        "anchor": "Complex-Temperature Singularities of Ising Models: We report new results on complex-temperature properties of Ising models.\nThese include studies of the $s=1/2$ model on triangular, honeycomb, kagom\\'e,\n$3 \\cdot 12^2$, and $4 \\cdot 8^2$ lattices. We elucidate the complex--$T$ phase\ndiagrams of the higher-spin 2D Ising models, using calculations of partition\nfunction zeros. Finally, we investigate the 2D Ising model in an external\nmagnetic field, mapping the complex--$T$ phase diagram and exploring various\nsingularities therein. For the case $\\beta H=i\\pi/2$, we give exact results on\nthe phase diagram and obtain susceptibility exponents $\\gamma'$ at various\nsingularities from low-temperature series analyses.",
        "positive": "Determination of constant lattice spacing trajectories in lattice QCD: We argue that lattice simulations of full QCD with varying quark mass are\nbest conducted at fixed lattice spacing rather than at fixed $\\beta$. We\npresent techniques which enable this to be carried out effectively, namely the\ntuning in bare parameter space and efficient stochastic estimation of the\nfermion determinant. Results and tests of the method are presented. We discuss\nother applications of such techniques."
    },
    {
        "anchor": "Reaching the chiral limit in many flavor systems: We present a brief overview of our recent lattice studies of SU(3) gauge\ntheory with N_f = 8 and 12 fundamental fermions, including some new and\nyet-unpublished results.\n  To explore relatively unfamiliar systems beyond lattice QCD, we carry out a\nwide variety of investigations with the goal of synthesizing the results to\nbetter understand the non-perturbative dynamics of these systems.\n  All our findings are consistent with conformal infrared dynamics in the\n12-flavor system, but with 8 flavors we observe puzzling behavior that requires\nfurther investigation.\n  Our new Monte Carlo renormalization group technique exploits the Wilson flow\nto obtain more direct predictions of a 12-flavor IR fixed point.\n  Studies of N_f = 12 bulk and finite-temperature transitions also indicate IR\nconformality, while our current results for the 8-flavor phase diagram do not\nyet provide clear signs of spontaneous chiral symmetry breaking.\n  From the Dirac eigenvalue spectrum we extract the mass anomalous dimension\ngamma_m, and predict gamma*_m = 0.32(3) at the 12-flavor fixed point.\n  The N_f = 8 system again shows interesting behavior, with a large anomalous\ndimension across a wide range of energy scales.\n  We use the eigenvalue density to predict the chiral condensate, and compare\nthis approach with direct and partially-quenched measurements.",
        "positive": "Multiple right-hand-side setup for the DD-\u03b1AMG: The setup cost of a modern solver such as DD-\\alpha AMG (Wuppertal Multigrid)\nis a significant contribution to the total time spent on solving the Dirac\nequation, and in HMC it can even be dominant. We present an improved\nimplementation of this algorithm with modified computation order in the setup\nprocedure. By processing multiple right-hand sides simultaneously we can\nalleviate many of the performance issues of the default single right-hand-side\nsetup. The main improvements are as follows: By combining multiple right-hand\nsides the message size for off-chip communication is larger, which leads to\nbetter utilization of the network bandwidth. Many matrix-vector products are\nreplaced by matrix-matrix products, leading to better cache reuse. The\nsynchronization overhead inflicted by on-chip parallelization (threading),\nwhich is becoming crucial on many-core architectures such as the Intel Xeon\nPhi, is effectively reduced. In the parts implemented so far, we observe a\nspeedup of roughly 3x compared to the optimized version of the single\nright-hand-side setup on realistic lattices."
    },
    {
        "anchor": "Valence-Quark Distribution of the Kaon and Pion from Lattice QCD: We present the first lattice-QCD calculation of the kaon valence-quark\ndistribution functions using the large-momentum effective theory (LaMET)\napproach. The calculation is performed with multiple pion masses with the\nlightest one around 220 MeV, 2 lattice spacings $a=0.06$ and 0.12 fm,\n$(M_\\pi)_\\text{min} L \\approx 5.5$, and high statistics ranging from 11,600 to\n61,312 measurements. We also calculate the valence-quark distribution of pion\nand find it to be consistent with the FNAL E615 experimental results, and our\nratio of the $u$ quark PDF in the kaon to that in the pion agrees with the CERN\nNA3 experiment. We also make predictions of the strange-quark distribution of\nthe kaon.",
        "positive": "Lattice calculation of the pion transition form factor $\u03c0^0 \\to\n  \u03b3^* \u03b3^*$: We calculate the $\\pi^0\\to \\gamma^*\\gamma^*$ transition form factor ${\\cal\nF}_{\\pi^0\\gamma^*\\gamma^*}(q_1^2,q_2^2)$ in lattice QCD with two flavors of\nquarks. Our main motivation is to provide the input to calculate the\n$\\pi^0$-pole contribution to hadronic light-by-light scattering in the muon\n$(g-2)$, $a_\\mu^{\\rm HLbL;\\pi^0}$. We therefore focus on the region where both\nphotons are spacelike up to virtualities of about $1.5~$GeV$^2$, which has so\nfar not been experimentally accessible. Results are obtained in the continuum\nat the physical pion mass by a combined extrapolation. We reproduce the\nprediction of the chiral anomaly for real photons with an accuracy of about\n$8-9\\%$. We also compare to various recently proposed models and find\nreasonable agreement for the parameters of some of these models with their\nphenomenological values. Finally, we use the parametrization of our lattice\ndata by these models to calculate $a_\\mu^{\\rm HLbL;\\pi^0}$."
    },
    {
        "anchor": "Three-particle scattering amplitudes from a finite volume formalism: We present a quantization condition for the spectrum of a system composed of\nthree identical bosons in a finite volume with periodic boundary conditions.\nThis condition gives a relation between the finite volume spectrum and infinite\nvolume scattering amplitudes. The quantization condition presented is an\nintegral equation that in general must be solved numerically. However, for\nsystems with an attractive two-body force that supports a two-body bound-state,\na diboson, and for energies below the diboson breakup, the quantization\ncondition reduces to the well-known Luscher formula with exponential\ncorrections in volume that scale with the diboson binding momentum. To\naccurately determine infinite volume phase shifts, it is necessary to\nextrapolate the phase shifts obtained from the Luscher formula for the\nboson-diboson system to the infinite volume limit. For energies above the\nbreakup threshold, or for systems with no two-body bound-state (with only\nscattering states and resonances) the Luscher formula gets power-law volume\ncorrections and consequently fails to describe the three-particle system. These\ncorrections are nonperturbatively included in the quantization condition\npresented.",
        "positive": "Improved lattice QCD with quarks: the 2 dimensional case: QCD in two dimensions is investigated using the improved fermionic lattice\nHamiltonian proposed by Luo, Chen, Xu, and Jiang. We show that the improved\ntheory leads to a significant reduction of the finite lattice spacing errors.\nThe quark condensate and the mass of lightest quark and anti-quark bound state\nin the strong coupling phase (different from t'Hooft phase) are computed. We\nfind agreement between our results and the analytical ones in the continuum."
    },
    {
        "anchor": "Automated Code Generation for Lattice Quantum Chromodynamics and beyond: We present here our ongoing work on a Domain Specific Language which aims to\nsimplify Monte-Carlo simulations and measurements in the domain of Lattice\nQuantum Chromodynamics. The tool-chain, called Qiral, is used to produce\nhigh-performance OpenMP C code from LaTeX sources. We discuss conceptual issues\nand details of implementation and optimization. The comparison of the\nperformance of the generated code to the well-established simulation software\nis also made.",
        "positive": "Investigating Spontaneous SO(10) Symmetry Breaking in Type IIB Matrix\n  Model: Non-perturbative formulations are essential to understand the dynamical\ncompactification of extra dimensions in superstring theories. The type IIB\n(IKKT) matrix model in the large-$N$ limit is one such conjectured formulation\nfor a ten-dimensional type IIB superstring. In this model, a smooth spacetime\nmanifold is expected to emerge from the eigenvalues of the ten bosonic\nmatrices. When this happens, the SO(10) symmetry in the Euclidean signature\nmust be spontaneously broken. The Euclidean version has a severe sign problem\nsince the Pfaffian obtained after integrating out the fermions is inherently\ncomplex. In recent years, the complex Langevin method (CLM) has successfully\ntackled the sign problem. We apply the CLM method to study the Euclidean\nversion of the type IIB matrix model and investigate the possibility of\nspontaneous SO(10) symmetry breaking. In doing so, we encounter a\nsingular-drift problem. To counter this, we introduce supersymmetry-preserving\ndeformations with a Myers term. We study the spontaneous symmetry breaking in\nthe original model at the vanishing deformation parameter limit. Our analysis\nindicates that the phase of the Pfaffian induces the spontaneous SO(10)\nsymmetry breaking in the Euclidean type IIB model."
    },
    {
        "anchor": "Accurate Determinations of $\u03b1_s$ from Realistic Lattice QCD: We obtain a new value for the QCD coupling constant by combining lattice QCD\nsimulations with experimental data for hadron masses. Our lattice analysis is\nthe first to: 1) include vacuum polarization effects from all three light-quark\nflavors (using MILC configurations); 2) include third-order terms in\nperturbation theory; 3) systematically estimate fourth and higher-order terms;\n4) use an unambiguous lattice spacing; and 5) use an $\\order(a^2)$-accurate QCD\naction. We use 28~different (but related) short-distance quantities to obtain\n$\\alpha_{\\bar{\\mathrm{MS}}}^{(5)}(M_Z) = 0.1170(12)$.",
        "positive": "High Statistics Analysis using Anisotropic Clover Lattices: (II)\n  Three-Baryon Systems: We present the results of an exploratory Lattice QCD calculation of\nthree-baryon systems through a high-statistics study of one ensemble of\nanisotropic clover gauge-field configurations with a pion mass of m_\\pi ~ 390\nMeV. Because of the computational cost of the necessary contractions, we focus\non correlation functions generated by interpolating-operators with the quantum\nnumbers of the $\\Xi^0\\Xi^0 n$ system, one of the least demanding three baryon\nsystems in terms of the number of contractions. We find that the ground state\nof this system has an energy of E_{\\Xi^0\\Xi^0n}= 3877.9\\pm 6.9\\pm 9.2\\pm3.3 MeV\ncorresponding to an energy-shift due to interactions of \\delta\nE_{\\Xi^0\\Xi^0n}=E_{\\Xi^0\\Xi^0n}-2M_{\\Xi^0} -M_n=4.6\\pm 5.0\\pm 7.9\\pm 4.2 MeV.\nThere are a significant number of time-slices in the three-baryon correlation\nfunction for which the signal-to-noise ratio is only slowly degrading with\ntime. This is in contrast to the exponential degradation of the signal-to-noise\nratio that is observed at larger times, and is due to the suppressed overlap of\nthe source and sink interpolating-operators that are associated with the\nvariance of the three-baryon correlation function onto the lightest eigenstates\nin the lattice volume\n  (mesonic systems). As one of the motivations for this area of exploration is\nthe calculation of the structure and reactions of light nuclei, we also present\ninitial results for a system with the quantum numbers of the triton (pnn). This\npresent work establishes a path to multi-baryon systems, and shows that Lattice\nQCD calculations of the properties and interactions of systems containing four\nand five baryons are now within sight."
    },
    {
        "anchor": "On the consistency of recent QCD lattice data of the baryon ground-state\n  masses: In our recent analysis of lattice data of the BMW, LHPC and PACS-CS groups we\ndetermined a parameter set of the chiral Lagrangian that allows a simultaneous\ndescription of the baryon octet and decuplet masses as measured by those\nlattice groups. The results on the baryon spectrum of the HSC group were\nrecovered accurately without their inclusion into our 6 parameter fit. We show\nthat the same parameter set provides an accurate reproduction of the recent\nresults of the QCDSF-UKQCD group probing the baryon masses at quite different\nquark masses. This shows a remarkable consistency amongst the different lattice\nsimulations. With even more accurate lattice data in the near future it will\nbecome feasible to determine all low-energy parameters relevant at N$^3$LO.",
        "positive": "Advancing real-time Yang-Mills: towards real-time observables from first\n  principles: The complex Langevin (CL) method shows great promise in enabling the\ncalculation of observables for theories with complex actions. Nevertheless,\nreal-time quantum field theories have remained largely unsolved due to the\nparticular severity of the sign problem. In this contribution, we discuss our\nrecent progress in applying CL to a thermal SU(2) Yang-Mills theory on a 3+1\ndimensional lattice. We present our anisotropic kernel that stabilizes the CL\napproach for real times longer than the inverse temperature - a first for\nYang-Mills theory. We provide explicit evidence of reproducing symmetries and\nrelations among different types of propagators when the complex time path\napproaches the Schwinger-Keldysh contour. This method paves the way for\ncalculating transport coefficients and other real-time observables from first\nprinciples."
    },
    {
        "anchor": "Monte Carlo methods in continuous time for lattice Hamiltonians: We solve a variety of sign problems for models in lattice field theory using\nthe Hamiltonian formulation, including Yukawa models and simple lattice gauge\ntheories. The solutions emerge naturally in continuous time and use the dual\nrepresentation for the bosonic fields. These solutions allow us to construct\nquantum Monte Carlo methods for these problems. The methods could provide an\nalternative approach to understanding non-perturbative dynamics of some lattice\nfield theories.",
        "positive": "Inclusive semileptonic $B$-decays from lattice QCD: We present the lattice QCD calculation of inclusive semileptonic $B_s$-meson\ndecays. We follow a recently proposed method, which is based on the extraction\nof smeared spectral densities from Euclidean correlation functions and on the\nnumerical reconstruction of the integration kernel relevant for the inclusive\ndecay rate calculation. We compute four-point Euclidean correlation functions\nusing JLQCD and ETM gauge ensembles with unphysically light $b$-quark masses,\nand apply two different methods for the integration kernel reconstruction.\nFinally, we show that the lattice results obtained in this work are in good\nagreement with the analytic predictions of the operator-product-expansion. This\nopens the path for a future full lattice QCD calculation to be used as\ntheoretical input for the determination of the magnitude of the CKM element\n$V_{cb}$."
    },
    {
        "anchor": "Nucleon Decay Matrix Elements for Domain-Wall Fermions: We report on the nucleon decay matrix elements with domain-wall fermions in\nquenched approximation. Results from direct and indirect method are compared\nwith a focus on the process of a proton decaying to a pion and a lepton. We\ndiscuss the renormalization necessary for the matching to the continuum theory.\nPreliminary results for the renormalized chiral lagrangian parameters are\npresented.",
        "positive": "Thermodynamics of (2+1)-flavor QCD: We report on the status of our QCD thermodynamics project. It is performed on\nthe QCDOC machine at Brookhaven National Laboratory and the APEnext machine at\nBielefeld University. Using a 2+1 flavor formulation of QCD at almost realistic\nquark masses we calculated several thermodynamical quantities. In this\nproceeding we show the susceptibilites of the chiral condensate and the\nPolyakov loop, the static quark potential and the spatial string tension."
    },
    {
        "anchor": "Mass Spectra of $D_s$ and $\u03a9_c$ in Lattice QCD with $N_f= 2+1+1$\n  Domain-Wall Quarks: We perform hybrid Monte Carlo simulation of lattice QCD with $N_f=2+1+1 $\noptimal domain-wall quarks on the $32^3 \\times 64 $ lattice with lattice\nspacing $a \\sim 0.06$ fm, and generate a gauge ensemble with physical $s$ and\n$c$ quarks, and pion mass $\\sim 280 $ MeV. Using 2-quark (meson) and 3-quark\n(baryon) interpolating operators, the mass spectra of the lowest-lying states\ncontaining $s$ and $c$ quarks ($D_s$ and $\\Omega_c$) are extracted\n\\cite{Chen:2017kxr}, which turn out in good agreement with the high energy\nexperimental values, together with the predictions of the charmed baryons which\nhave not been observed in experiments. For the five new narrow $\\Omega_c$\nstates observed by the LHCb Collaboration \\cite{Aaij:2017nav}, the lowest-lying\n$\\Omega_c(3000)$ agrees with our predicted mass $3015(29)(34)$ MeV of the\nlowest-lying $\\Omega_c$ with $J^P = 1/2^{-}$. This implies that the $ J^P $ of\n$ \\Omega_c(3000) $ is $ 1/2^- $.",
        "positive": "The Phase Diagram of Compact QED Coupled to a Four-Fermi Interaction: Compact lattice Quantum Electrodynamics (QED) with four species of fermions\nis simulated with massless quarks by using the $\\chi$QED scheme of adding a\nfour-fermi interaction to the action. Simulations directly in the chiral limit\nof massless quarks are done with high statistics on $8^4$, and $16^4$ lattices,\nand the phase diagram, parameterized by the gauge and the four-fermi couplings,\nis mapped out. The line of monopole condensation transitions is separate from\nthe line of chiral symmetry restoration. The simulation results indicate that\nthe monopole condensation transition is first order while the chiral transition\nis second order. The challenges in determining the Universality class of the\nchiral transition are discussed. If the scaling region for the chiral\ntransition is sufficiently wide, the $16^4$ simulations predict critical\nindices far from mean field values. We discuss a speculative scenario in which\nanti-screening provided by double-helix strands of monopole and anti-monopole\nloops are the agent that balances the screening of fermion anti-fermion pairs\nto produce an ultra-violet fixed point in the electric coupling."
    },
    {
        "anchor": "Lattice study of the simplified model of M-theory for larger gauge\n  groups: Lattice discretization of the supersymmetric Yang-Mills quantum mechanics is\ndis cussed. First results of the quenched Monte Carlo simulations, for D=4 and\nwith higher g auge groups (3 <= N <= 8), are presented. We confirm an earlier\n(N=2) evidence tha t the system reveals different behaviours at low and high\ntemperatures separated by a narrow transiti on region. These two regimes may\ncorrespond to a black hole and elementary excitations phases conjectured in the\nM-theory. Dependence of the \"transition temperature\" on N is consistent with 't\nHooft scaling and shows a smooth saturation of lattice results towards the\nlarge N limit. Is not yet resolved if the observed change between the two\nregimes corresponds to a genuine phase transition or to a gentle crossover . A\nnew, noncompact formulation of the lattice model is also proposed and its\nadvantages are briefly discussed.",
        "positive": "Pion-nucleon scattering in the Roper channel from lattice QCD: We present a lattice QCD study of $N\\pi$ scattering in the positive-parity\nnucleon channel, where the puzzling Roper resonance $N^*(1440)$ resides in\nexperiment. The study is based on the PACS-CS ensemble of gauge configurations\nwith $N_f=2+1$ Wilson-clover dynamical fermions, $m_\\pi \\simeq 156~$MeV and\n$L\\simeq 2.9~$fm. In addition to a number of $qqq$ interpolating fields, we\nimplement operators for $N\\pi$ in $p$-wave and $N\\sigma$ in $s$-wave. In the\ncenter-of-momentum frame we find three eigenstates below 1.65 GeV. They are\ndominated by $N(0)$, $N(0)\\pi(0)\\pi(0)$ (mixed with $N(0)\\sigma(0)$) and\n$N(p)\\pi(-p)$ with $p\\simeq 2\\pi/L$, where momenta are given in parentheses.\nThis is the first simulation where the expected multi-hadron states are found\nin this channel. The experimental $N\\pi$ phase-shift would -- in the\napproximation of purely elastic $N\\pi$ scattering -- imply an additional\neigenstate near the Roper mass $m_R\\simeq 1.43~$GeV for our lattice size. We do\nnot observe any such additional eigenstate, which indicates that $N\\pi$ elastic\nscattering alone does not render a low-lying Roper. Coupling with other\nchannels, most notably with $N\\pi\\pi$, seems to be important for generating the\nRoper resonance, reinforcing the notion that this state could be a dynamically\ngenerated resonance. Our results are in line with most of previous lattice\nstudies based just on $qqq$ interpolators, that did not find a Roper eigenstate\nbelow $1.65~$GeV. The study of the coupled-channel scattering including a\nthree-particle decay $N\\pi\\pi$ remains a challenge."
    },
    {
        "anchor": "Resonance Parameters of the rho-Meson from Lattice QCD: We perform a non-perturbative lattice calculation of the P-wave pion-pion\nscattering phase in the rho-meson decay channel using two flavors of maximally\ntwisted mass fermions at pion masses ranging from 480 MeV to 290 MeV. Making\nuse of finite-size methods, we evaluate the pion-pion scattering phase in the\ncenter-of-mass frame and two moving frames. Applying an effective range\nformula, we find a good description of our results for the scattering phase as\na function of the energy covering the resonance region. This allows us to\nextract the rho-meson mass and decay width and to study their quark mass\ndependence.",
        "positive": "Most charming dibaryon near unitarity: We present a first study on a pair of triply charmed baryons,\n$\\Omega_{ccc}\\Omega_{ccc}$ in the $^1S_0$ channel, on the basis of the HAL QCD\nmethod. The measurements are perfomed on the $(2+1)$-flavor lattice QCD\nconfigurations with nearly physical light-quark masses and physical charm-quark\nmass. We show that the system with the Coulomb repulsion taking into account\nthe charge form factor of $\\Omega_{ccc}$ leads to the scattering length\n$a^\\mathrm{C}_0\\simeq-19$ fm and the effective range\n$r^\\mathrm{C}_\\mathrm{eff}\\simeq0.45$ fm, which indicates\n$\\Omega_{ccc}\\Omega_{ccc}$ is located in the unitary regime."
    },
    {
        "anchor": "The $\u03b7^\\prime$ meson at the physical point with $N_f=2$ Wilson\n  twisted mass fermions: We present results for the eta prime meson and the topological susceptibility\nin two flavour lattice QCD. The results are obtained using Wilson twisted mass\nfermions at maximal twist with pion masses ranging from 340 MeV down to the\nphysical point. A comparison to literature values is performed giving a handle\non discretisation effects.",
        "positive": "Restoring canonical partition functions from imaginary chemical\n  potential: Using GPGPU techniques and multi-precision calculation we developed the code\nto study QCD phase transition line in the canonical approach. The canonical\napproach is a powerful tool to investigate sign problem in Lattice QCD. The\ncentral part of the canonical approach is the fugacity expansion of the grand\ncanonical partition functions. Canonical partition functions $Z_n(T)$ are\ncoefficients of this expansion. Using various methods we study properties of\n$Z_n(T)$. At the last step we perform cubic spline for temperature dependence\nof $Z_n(T)$ at fixed $n$ and compute baryon number susceptibility $\\chi_B/T^2$\nas function of temperature. After that we compute numerically $\\partial\\chi/\n\\partial T$ and restore crossover line in QCD phase diagram. We use improved\nWilson fermions and Iwasaki gauge action on the $16^3 \\times 4$ lattice with\n$m_{\\pi}/m_{\\rho} = 0.8$ as a sandbox to check the canonical approach. In this\nframework we obtain coefficient in parametrization of crossover line\n$T_c(\\mu_B^2)=T_c\\left(c-\\kappa\\, \\mu_B^2/T_c^2\\right)$ with $\\kappa = -0.0453\n\\pm 0.0099$."
    },
    {
        "anchor": "Magnetic polarizability of a charged pion from four-point functions in\n  lattice QCD: Electromagnetic dipole polarizabilities are fundamental properties of a\nhadron that represent its resistance to deformation under external fields. For\na charged hadron, the presence of acceleration and Landau levels complicates\nthe isolation of its deformation energy in the conventional background field\nmethod. In this work, we explore a general method based on four-point functions\nin lattice QCD that takes into account all photon, quark and gluon\ninteractions. The electric polarizability ($\\alpha_E$) has been determined from\nthe method in a previous proof-of-principle simulation. Here we focus on the\nmagnetic polarizability ($\\beta_M$) using the same quenched Wilson action on a\n$24^3\\times 48$ lattice at $\\beta=6.0$ with pion mass from 1100 to 370 MeV. The\nresults from the connected diagrams show a large cancellation between the\nelastic and inelastic contributions, leading to a relatively small and negative\nvalue for $\\beta_M$ consistent with chiral perturbation theory. We also discuss\nthe mechanism for $\\alpha_E+\\beta_M$ from combining the two studies.",
        "positive": "MCRG study of 12 fundamental flavors with mixed fundamental-adjoint\n  gauge action: I discuss the infrared behavior of the SU(3) gauge model with 12 fundamental\nfermions. Using a Monte Carlo renormalization group technique I investigate the\nfixed point structure in the chiral limit and show that this system has an\ninfrared fixed point and consequently conformal infrared dynamics. I am able to\nreach the FP by using a new analysis method for the 2-lattice matching MCRG\ntechnique that significantly reduces finite volume effects and by choosing a\nlattice action that avoids a spurious ultraviolet fixed point created by strong\ncoupling lattice artifacts."
    },
    {
        "anchor": "Study of quark mass dependence of binding energy for light nuclei in 2+1\n  flavor lattice QCD: We investigate the formation of light nuclei with the nuclear mass number\nless than or equal to four in 2+1 flavor QCD using a non-perturbative improved\nWilson quark and Iwasaki gauge actions. The quark mass is decreased from our\nprevious work to the one corresponding to the pion mass of 0.30 GeV. In each\nmulti-nucleon channel, the energy shift of the ground state relative to the\nassembly of free nucleons is calculated on two volumes, whose spatial extents\nare 4.3 fm and 5.8 fm. From the volume dependence of the energy shift, we\ndistinguish a bound state of multi nucleons from an attractive scattering\nstate. We find that all the ground states measured in this calculation are\nbound states. As in the previous studies at larger $m_\\pi$, our result\nindicates that at $m_\\pi = 0.30$ GeV the effective interaction between nucleons\nin the light nuclei is relatively stronger than the one in nature, since the\nresults for the binding energies are larger than the experimental values and a\nbound state appears in the dineutron channel, which is not observed in\nexperiment. Possible sources of systematic error in this calculation are\ndiscussed.",
        "positive": "Wilson fermions with imaginary chemical potential: We study the phase structure of imaginary chemical potential.\n  We calculate the Polyakov loop using clover-improved Wilson action and\nrenormalization improved gauge action. We obtain a two-state signals indicating\nthe first order phase transition for $\\beta = 1.9, \\mu_I = 0.2618,\n\\kappa=0.1388$ on $8^3\\times 4$ lattice volume We also present a result of the\nmatrix reduction formula for the Wilson fermion."
    },
    {
        "anchor": "The monopole mass in the random percolation gauge theory: We study the behaviour of the monopole at finite temperature in the\n(2+1)-dimensional lattice gauge theory dual to the percolation model; by\nexploiting the correspondences to statistical systems, we possess powerful\ntools to evaluate the monopole mass both above and below the critical\ntemperature with high-precision Monte Carlo simulations.",
        "positive": "A dual view of the 3d Heisenberg model and the abelian projection: The Heisenberg model in 3d is studied from a dual point of view. It is shown\nthat it can have vortex configurations, carrying a conserved charge(U(1)\nsymmetry). Vortices condens in the disordered phase. A disorder parameter\n$\\leftangle\\mu\\rightangle$ is defined dual to the magnetization $\\leftangle\\vec\nn\\rightangle$, which signals condensation of vortices, i.e. spontaneous\nbreaking of the dual U(1) symmetry. This study sheds light on the procedure\nknown as abelian projection in non abelian gauge theories."
    },
    {
        "anchor": "Partition Function Zeros in Non-compact QED: The lowest zeros of the lattice partition function for non-compact QED are\nfound in the complex fermion mass plane on $6^4$, $8^4$ and $10^4$ lattices at\nintermediate values of the coupling. The scaling of the low lying zeros with\nlattice size is analysed.",
        "positive": "Lattice spectroscopy with focus on exotics: Recent lattice QCD results on the hadron spectroscopy with beauty and charm\nquarks is reviewed. The focus of the review are exotic hadrons, while\nnon-lattice approaches and conventional hadrons are reported as well. We\ndiscuss the recently discovered $\\Omega_c^*$, a charmonium state with spin\nthree, $P_c$ pentaquarks, $B_c(2S)$ and $\\Lambda_b^*$, the long-standing\nchallenges for theory $Z_c$, $Z_b$ and $X(3872)$, and we review predictions for\nyet undiscovered states $bb\\bar q\\bar q$, $\\bar bb\\bar bb$, highly excited and\nhybrid $\\bar bb$, baryons with bottom quarks and still-missing $B_{s}$ mesons."
    },
    {
        "anchor": "The type of the phase transition and coupling values in \u03bb\u03c6^4\n  model: The temperature induced phase transition is investigated in the one-component\nscalar field \\phi^4 model on the lattice. Using the GPU cluster a huge amount\nof Monte Carlo simulation data is collected for a wide interval of coupling\nvalues. This gives a possibility to determine the low bound on the coupling\nconstant \\lambda_0 when the transition happens and investigate its type. We\nfound that for the values of \\lambda close to this bound a weak-first-order\nphase transition takes place. It converts into a second order one with the\nincrease of \\lambda. A comparison with the results obtained in analytic and\nnumeric calculations by other authors is given.",
        "positive": "QCDF90: Lattice QCD with Fortran 90: We have used Fortran 90 to implement lattice QCD. We have designed a set of\nmachine independent modules that define fields (gauge, fermions, scalars,\netc...) and overloaded operators for all possible operations between fields,\nmatrices and numbers. With these modules it is very simple to write high-level\nefficient programs for QCD simulations. To increase performances our modules\nalso implements assignments that do not require temporaries, and a machine\nindependent precision definition. We have also created a useful compression\nprocedure for storing the lattice configurations, and a parallel implementation\nof the random generators. We have widely tested our program and modules on\nseveral parallel and single processor supercomputers obtaining excellent\nperformances."
    },
    {
        "anchor": "Extracting the electro-magnetic pion form factor from QCD in a finite\n  volume: We consider finite volume effects on the electromagnetic form factor of the\npion. We compute the peudoscalar-vector-pseudoscalar correlator in the\n$\\epsilon$ expansion of chiral perturbation theory up to the next-to-leading\norder and find a way to remove the dominant part, which comes from a\ncontribution of the pion zero-mode. Inserting non-zero momentum to relevant\noperators (or taking a subtraction of the correlators at different\ntime-slices), and taking an appropriate ratio of them, one can automatically\ncancel the zero-mode's contribution, which becomes non-perturbatively large\n$\\sim \\mathcal{O}(100 \\%)$ in the $\\epsilon$ regime. The remaining finite\nvolume dependence, which comes from the non-zero momentum modes, is shown to be\nperturbatively small even in such an extremal case. Since the zero-mode's\ndominance is universal in any finite volume scaling, and we do not rely on any\nparticular feature of the $\\epsilon$ expansion, our method has a wide\napplication to many other correlators of QCD.",
        "positive": "Numerical computation of the beta function of large N SU(N) gauge theory\n  coupled to an adjoint Dirac fermion: We use a single site lattice in four dimensions to study the scaling of large\nN Yang-Mills field coupled to a single massless Dirac fermion in the adjoint\nrepresentation. We use the location of the strong to weak coupling transition\ndefined through the eigenvalues of the folded Wilson loop operator to set a\nscale. We do not observe perturbative scaling in the region studied in this\npaper. Instead, we observe that the scale changes very slowly with the bare\ncoupling. The lowest eigenvalue of the overlap Dirac operator is another scale\nthat shows similar behavior as a function of the lattice coupling. We speculate\nthat this behavior is due to the beta function appoaching close to a zero."
    },
    {
        "anchor": "Fixed Point Four-Fermi Theories: I review dynamical chiral symmetry breaking in four-fermi models, including\nresults of Monte Carlo simulations with dynamical fermions. For 2<d<4, where\nthe phase transition defines an ultraviolet fixed point of the renormalisation\ngroup, the continuum theory may either be describable using the large-N_f\nexpansion, as in the case of the Gross-Neveu model, or be intrinsically\nnon-perturbative, as in the case of the Thirring model. For d=4, the models are\ntrivial and are described by a mean field equation of state with logarithmic\ncorrections to scaling, which may nonetheless define new universality classes\ndistinct from those of ferromagnetism.",
        "positive": "Investigating QCD Vacuum on the lattice: Investigations on the structure of QCD vacuum from first principles can be\ndone on the lattice. The mechanism of confinement is an example: results from\nlattice on it are reviewed."
    },
    {
        "anchor": "Mass Spectra of Pentaquarks -- Overlap versus Wilson Fermions: We investigate the mass spectra of $\\Theta^+(udud\\bar s)$ in quenched lattice\nQCD, with overlap and Wilson fermions respectively. Using three different\ninterpolating operators, we measure their correlation matrix, and extract the\nmass spectra in even and odd parity channels, for 100 gauge configurations\ngenerated with single plaquette action at $\\beta=6.1$ on the $20^3 \\times 40$\nlattice. The lowest $ 1/2^- $ state agrees with the $ KN $ s-wave scattering\nstate, for both fermion schemes. On the other hand, for the lowest $ 1/2^+ $\nstate, it is different from any hadron scattering states for the overlap\nfermion, while it seems to agree with $ KN^* $ s-wave for the Wilson fermion.",
        "positive": "Mixed action with Borici-Creutz fermions on staggered sea: Mixed action lattice QCD with Borici-Creutz valence quarks on staggered sea\nis investigated. The counter terms in Borici-Creutz action are fixed\nnonperturbatively to restore the broken parity and time symmetries. On symmetry\nrestoration, the usual signatures of partial quenching / unitarity violation\nlike negative scalar correlator are observed. The size of unitarity violation\ndue to different discretization of valence and sea quark is determined by\nmeasuring $\\Delta_{\\rm mix}$ and is found to be comparable with other mixed\naction studies."
    },
    {
        "anchor": "Finite Density Algorithm in Lattice QCD -- a Canonical Ensemble Approach: I will review the finite density algorithm for lattice QCD based on finite\nchemical potential and summarize the associated difficulties. I will propose a\ncanonical ensemble approach which projects out the finite baryon number sector\nfrom the fermion determinant. For this algorithm to work, it requires an\nefficient method for calculating the fermion determinant and a Monte Carlo\nalgorithm which accommodates unbiased estimate of the probability. I shall\nreport on the progress made along this direction with the Pad\\'{e} - Z$_2$\nestimator of the determinant and its implementation in the newly developed\nNoisy Monte Carlo algorithm.",
        "positive": "Curing O(a) Errors in 3-D Lattice SU(2) x U(1) Higgs Theory: We show how to make O(a) corrections in the bare parameters of 3-D lattice\nSU(2) times U(1) Higgs theory which remove O(a) errors in the match between the\ninfrared behavior and the infrared behavior of the continuum theory. The\ncorrections substantially improve the convergence of lattice data to a small a\nlimit."
    },
    {
        "anchor": "Scaling study of an improved fermion action on quenched lattices: We present scaling studies for heavy-quark observables calculated with an\n$O(a^2)$-improved fermion action on tree-level Symanzik improved gauge\nconfigurations. Lattices of $1/a = $ 2.0-3.8 GeV with an equal physical volume\n1.6 fm are used. The results are compared with the standard domain-wall and\nnaive Wilson fermions.",
        "positive": "Search for continuous phase transitions in 5D pure SU(2) lattice gauge\n  theory: The Renormalization Group (RG) is one of the central and modern techniques in\nquantum field theory. Indeed, quantum field theories can be understood as flows\nbetween fixed points of the RG flow, which represent Conformal Field Theories\n(CFT's). Hence, the search and classification of yet unknown non-trivial CFT's\nis a legitimate endeavor. Analytical considerations point to the existence of\nsuch a fixed point in pure SU(2) Yang-Mills fields in 5D. This issue has\nalready been addressed, although inconclusively. We search for this putative\nfixed point using lattice Monte Carlo methods. An extended discussion can be\nfound in [1]."
    },
    {
        "anchor": "Nucleon structure from 2+1f dynamical DWF lattice QCD at nearly physical\n  pion mass: Current status of nucleon structure calculations with joint RBC and UKQCD\n2+1-flavor dynamical domain-wall fermions (DWF) lattice QCD is reported: Two\nensembles with pion mass of about (m_\\pi=170) MeV and 250 MeV are used. The\nlattice cutoff is set at about 1.4 GeV, allowing a large spatial volume of\nabout (L=4.6) fm across while maintaining a sufficiently small residual\nbreaking of chiral symmetry with the dislocation-suppressing-determinant-ratio\n(DSDR) gauge action. We calculate all the isovector form factors and some low\nmoments of isovector structure functions. We confirm the finite-size effect in\nisovector axialvector-current form factors, in particular the deficit in the\naxial charge and its scaling in terms of (m_\\pi L), that we reported from our\nearlier calculation at heavier pion masses.",
        "positive": "Lattice QCD at finite isospin chemical potential and temperature: We simulate lattice QCD at a finite chemical potential $\\mu_I$ for isospin\n($I_3$) at zero and finite temperatures. At some $\\mu_I=\\mu_c$ QCD has a second\norder transition with mean-field critical exponents to a state where ($I_3$) is\nbroken spontaneously by a charged pion condensate. Heating the system with\n$\\mu_I > \\mu_c$ we find there is some temperature at which this condensate\nevaporates. This transition appears to be second order and mean-field at lower\n$\\mu_I$ values, and first order for $\\mu_I$ sufficiently large. We are\ndetermining the dependence of the finite temperature crossover $T_c$ on $\\mu_I$\nfor $\\mu_I < \\mu_c$. This is expected to be identical to $T_c$'s dependence on\nquark-number chemical potential $\\mu_q$ for small $\\mu_q$."
    },
    {
        "anchor": "Unitary Limit of Two-Nucleon Interactions in Strong Magnetic Fields: Two-nucleon systems are shown to exhibit large scattering lengths in strong\nmagnetic fields at unphysical quark masses, and the trends toward the physical\nvalues indicate that such features may exist in nature. Lattice QCD\ncalculations of the energies of one and two nucleons systems are performed at\npion masses of $m_\\pi\\sim 450$ and 806 MeV in uniform, time-independent\nmagnetic fields of strength {\\bf B}| \\sim 10^{19}$-$10^{20}$ Gauss to determine\nthe response of these hadronic systems to large magnetic fields. Fields of this\nstrength may exist inside magnetars and in peripheral relativistic heavy ion\ncollisions, and the unitary behavior at large scattering lengths may have\nimportant consequences for these systems.",
        "positive": "Gribov Copies in the Maximally Abelian Gauge and Confinement: We fix $SU(2)$ lattice gauge fields to the Maximally Abelian gauge in both\nthree and four dimensions. We extract the corresponding $U(1)$ fields and\nmonopole current densities and calculate separately the confining string\ntensions arising from these $U(1)$ fields and monopole `condensates'. We\ngenerate multiple Gribov copies and study how the $U(1)$ fields and monopole\ndistributions vary between these different copies. As expected, we find\nsubstantial variations in the number of monopoles, their locations and in the\nvalues of the $U(1)$ field strengths. The string tensions extracted from\n`extreme' Gribov copies also differ but this difference appears to be no more\nthan about 20\\%. We also directly compare the fields of different Gribov\ncopies. We find that on the distance scales relevant to confinement the $U(1)$\nand monopole fluxes that disorder Wilson loops are highly correlated between\nthese different Gribov copies. All this suggests that while there is indeed a\nGribov copy problem the resulting ambiguity is, in this gauge and for the study\nof confinement, of limited importance."
    },
    {
        "anchor": "Scalar-Quark Systems and Chimera Hadrons in SU(3)_c Lattice QCD: Light scalar-quarks \\phi (colored scalar particles or idealized diquarks) and\ntheir color-singlet hadronic states are studied with quenched SU(3)_c lattice\nQCD in terms of mass generation in strong interaction without chiral symmetry\nbreaking. We investigate ``scalar-quark mesons'' \\phi^\\dagger \\phi and\n``scalar-quark baryons'' \\phi\\phi\\phi which are the bound states of\nscalar-quarks \\phi. We also investigate the bound states of scalar-quarks \\phi\nand quarks \\psi, i.e., \\phi^\\dagger \\psi, \\psi\\psi\\phi and \\phi\\phi\\psi, which\nwe name ``chimera hadrons''. All the new-type hadrons including \\phi are found\nto have a large mass even for zero bare scalar-quark mass m_\\phi=0 at\na^{-1}\\simeq 1GeV. We find that the constituent scalar-quark and quark picture\nis satisfied for all the new-type hadrons. Namely, the mass of the new-type\nhadron composed of m \\phi's and n \\psi's, M_{{m}\\phi+{n}\\psi}, satisfies\nM_{{m}\\phi+{n}\\psi}\\simeq {m} M_\\phi +{n} M_\\psi, where M_\\phi and M_\\psi are\nthe constituent scalar-quark and quark mass, respectively. M_\\phi at m_\\phi=0\nestimated from these new-type hadrons is 1.5-1.6GeV, which is larger than that\nof light quarks, M_\\psi\\simeq 400{\\rm MeV}. Therefore, in the systems of\nscalar-quark hadrons and chimera hadrons, scalar-quarks acquire large mass due\nto large quantum corrections by gluons. Together with other evidences of mass\ngenerations of glueballs and charmonia, we conjecture that all colored\nparticles generally acquire a large effective mass due to dressed gluon\neffects.",
        "positive": "Lattice QCD studies of the $\u0394$ baryon resonance and the\n  $K_0^\\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators\n  in determining the finite-volume spectrum: Studies of the $\\Delta$ baryon resonance and the $K_0^\\ast(700)$ and\n$a_0(980)$ meson resonances using $N_f=2+1$ lattice QCD for pion masses near\n200 MeV are presented. The $s$-wave scattering lengths for both the $I=1/2$ $N\n\\pi$ and $I=3/2$ $N \\pi$ channels and properties of the $\\Delta$ resonance are\nidentified from the finite-volume energy levels of the lattice simulation. The\nimportance of a three-quark $\\Delta$-operator in the $N\\pi$ system and\ntetraquark operators in the mesonic systems is investigated."
    },
    {
        "anchor": "Spectrum and mass anomalous dimension of SU(2) gauge theories with\n  fermions in the adjoint representation: from $N_f=1/2$ to $N_f=2$: We summarize our results concerning the spectrum and mass anomalous dimension\nof SU(2) gauge theories with various numbers of fermions in the adjoint\nrepresentation, where each Majorana fermion corresponds effectively to half a\nDirac flavour $N_f$. The most relevant examples for extensions of the standard\nmodel are supersymmetric Yang-Mills theory ($N_f=1/2$) and Minimal Walking\nTechnicolour ($N_f=2$). In addition to these theories we will also consider the\ncases of $N_f=1$ and $N_f=3/2$. The results comprise the particle spectrum of\nglueballs, triplet and singlet mesons, and possible fractionally charged spin\nhalf particles. In addition we will discuss our recent results for the mass\nanomalous dimension.",
        "positive": "Conformal Behavior in QCD: We give a new perspective on the properties of quarks and gluons at finite\ntemperature T in N_f = 2 ~ 6 QCD. We point out the existence of an IR fixed\npoint for the gauge coupling constant at T>T_c (T_c is the chiral phase\ntransition temperature). Based on this observation we predict theoretically and\nverify numerically that the correlation functions of a meson G(t) at T/T_c > 1\ndecay with a power-law corrected Yukawa-type decaying form, G(t)=c exp(-m\nt)/t^alpha in the \"conformal region\" defined by m < c Lambda_IR, where\nLambda_IR is the IR cutoff, m is the characteristic scale of the spectrum in\nthe meson cannel and c is a constant of order 1. The decaying form is the\ncharacteristics of conformal theories with an IR cutoff. We discuss in detail\nhow the resulting hyper scaling relation of physical observables may modify the\nexisting argument about the order of the chiral phase transition in the N_f=2\ncase."
    },
    {
        "anchor": "Effective Monopole Action at Finite Temperature in SU(2) Gluodynamics: Effective monopole action at finite temperature in SU(2) gluodynamics is\nstudied on anisotropic lattices. Using an inverse Monte-Carlo method and the\nblockspin transformation for space directions, we determine 4-dimensional\neffective monopole action at finite temperature. We get an almost perfect\naction in the continuum limit under the assumption that the action is composed\nof two-point interactions alone. It depends on a physical scale $b_s$ and the\ntemperature $T$. The temperature-dependence appears with respect to the\nspacelike monopole couplings in the deconfinement phase, whereas the timelike\nmonopole couplings do not show any appreciable temperature-dependence. The\ndimensional reduction of the 4-dimensional SU(2) gluodynamics ((SU(2))$_{4D}$)\nat high temperature is the 3-dimensional Georgi-Glashow model ($(GG)_{3D}$).\nThe latter is studied at the parameter region obtained from the dimensional red\nuction. We compare the effective instanton action of $(GG)_{3D}$ with the\ntimelike monopole action obtained from (SU(2))$_{4D}$. We find that both agree\nvery well for $T \\ge 2.4T_c$ at large $b$ region. The dimensional reduction\nworks well also for the effective action.",
        "positive": "Low-lying baryon masses using $N_f=2$ twisted mass clover-improved\n  fermions directly at the physical point: The masses of the low-lying baryons are evaluated using an ensemble with two\ndegenerate light twisted mass clover-improved quarks with mass tuned to\nreproduce the physical pion mass. The Iwasaki improved gluonic action is\nemployed. The coupling constant value corresponds to a lattice spacing of\n$a=0.0938(3)(2)$ fm, determined from the nucleon mass. We find that the clover\nterm supresses isospin symmetry breaking as compared to our previous results\nusing $N_f=2+1+1$ twisted mass fermions. The masses of the hyperons and charmed\nbaryons evaluated using this ensemble are in agreement with the experimental\nvalues. We provide predictions for the mass of the doubly charmed $\\Xi_{cc}^*$,\nas well as of the doubly and triply charmed $\\Omega$s that have not yet been\ndetermined experimentally."
    },
    {
        "anchor": "Status of the 0.8 Teraflops Supercomputer at Columbia: The first stage in the construction of the 0.8 Teraflops Supercomputer at\nColumbia, a working, two node parallel computer, has been successfully\ncompleted. The next stage, a 512 node, 26 Gigaflops prototype, is in its final\nconstruction phase. A general description and current status of the hardware\nand software is presented.",
        "positive": "Monopole condensation and colour confinement: The evidence is reviewed for the mechanism of colour confinement in QCD by\ndual superconductivity of the ground state, i.e. by condensation of monopoles."
    },
    {
        "anchor": "Quenched staggered light hadron spectroscopy from $48^3\\times64$ at\n  $\u03b2= 6.5$: We report our light hadron mass calculation based on an increased statistics\nof 250 quenched gauge configurations on a (48^3 \\times 64) lattice at (\\beta =\n6.5). Quark propagators are calculated for each of these configurations with\nstaggered wall source and point sink at quark mass values of (m_q = 0.01,\n0.005, 0.0025) and (0.00125). We also did additional calculations to improve\nour understanding of systematic biases arising from autocorrelation, source\nsize, and propagator calculations. Our earlier conclusions that the flavor\nsymmetry breaking is reduced and the ratio (m_N/m_\\rho (\\sim 1.25(4))) is small\nremains robust.",
        "positive": "Improved Actions for QCD Thermodynamics on the Lattice: Finite cut-off effects strongly influence the thermodynamics of lattice\nregularized QCD at high temperature in the standard Wilson formulation. We\nanalyze the reduction of finite cut-off effects in formulations of the\nthermodynamics of $SU(N)$ gauge theories with three different $O(a^2)$ and\n$O(a^4)$ improved actions. We calculate the energy density and pressure on\nfinite lattices in leading order weak coupling perturbation theory\n($T\\rightarrow \\infty$) and perform Monte Carlo simulations with improved\n$SU(3)$ actions at non-zero $g^2$. Already on lattices with temporal extent\n$N_\\tau=4$ we find a strong reduction of finite cut-off effects in the high\ntemperature limit, which persists also down to temperatures a few times the\ndeconfinement transition temperature."
    },
    {
        "anchor": "Quark number densities at imaginary chemical potential in $N_f=2$\n  lattice QCD with Wilson fermions and its model analyses: We investigate temperature ($T$) dependence of quark number densities ($n_q$)\nat imaginary and real chemical potential ($\\mu$) by using $N_f = 2$ lattice QCD\nand the hadron resonance gas (HRG) model. Quark number densities are calculated\nat imaginary $\\mu$ with lattice QCD on an $8^2 \\times 16 \\times 4$ lattice with\nthe clover-improved $N_f =2$ Wilson fermion action and the\nrenormalization-group-improved Iwasaki gauge action. The results are consistent\nwith the previous results of the staggered-type quark action. The $n_q$\nobtained are extrapolated to real $\\mu$ by assuming the Fourier series for the\nconfinement region and the polynomial series for the deconfinement region. The\nextrapolated results are consistent with the previous results of the Taylor\nexpansion method for the reweighting factor. The upper bound\n$(\\mu/T)_{\\mathrm{max}}$ of the region where the extrapolation is considered to\nbe reliable is estimated for each temperature $T$ . We test whether $T$\ndependence of nucleon and $\\Delta$-resonance masses can be determined from LQCD\ndata on $n_q$ at imaginary $\\mu$ by using the HRG model. In the test\ncalculation, nucleon and $\\Delta$-resonance masses reduce by about 10% in the\nvicinity of the pseudocritical temperature.",
        "positive": "The scalar pion form factor in two-flavor lattice QCD: We calculate the scalar form factor of the pion using two dynamical flavors\nof non-perturbatively $\\mathcal{O}(a)$-improved Wilson fermions, including both\nthe connected and the disconnected contribution to the relevant correlation\nfunctions. We employ the calculation of all-to-all propagators using stochastic\nsources and a generalized hopping parameter expansion. From the form factor\ndata at vanishing momentum transfer, $Q^2=0$, and two non-vanishing $Q^2$ we\nobtain an estimate for the scalar radius $\\left<r^2\\right>^\\pi_{_{\\rm S}}$ of\nthe pion at one value of the lattice spacing and for five different pion\nmasses. Using Chiral Perturbation Theory at next-to-leading order, we find\n$\\left<r^2\\right>^\\pi_{_{\\rm S}}=0.635\\pm0.016$ fm$^2$ at the physical pion\nmass (statistical error only). This is in good agreement with the\nphenomenological estimate from $\\pi\\pi$-scattering. The inclusion of the\ndisconnected contribution is essential for achieving this level of agreement."
    },
    {
        "anchor": "Implementing the three-particle quantization condition including higher\n  partial waves: We present an implementation of the relativistic three-particle quantization\ncondition including both $s$- and $d$-wave two-particle channels. For this, we\ndevelop a systematic expansion about threshold of the three-particle\ndivergence-free K matrix, $\\mathcal{K}_{\\mathrm{df,3}}$, which is a\ngeneralization of the effective range expansion of the two-particle K matrix,\n$\\mathcal{K}_2$. Relativistic invariance plays an important role in this\nexpansion. We find that $d$-wave two-particle channels enter first at quadratic\norder. We explain how to implement the resulting multichannel quantization\ncondition, and present several examples of its application. We derive the\nleading dependence of the threshold three-particle state on the two-particle\n$d$-wave scattering amplitude, and use this to test our implementation. We show\nhow strong two-particle $d$-wave interactions can lead to significant effects\non the finite-volume three-particle spectrum, including the possibility of a\ngeneralized three-particle Efimov-like bound state. We also explore the\napplication to the $3\\pi^+$ system, which is accessible to lattice QCD\nsimulations, where we study the sensitivity of the spectrum to the components\nof $\\mathcal{K}_{\\mathrm{df,3}}$. Finally, we investigate the circumstances\nunder which the quantization condition has unphysical solutions.",
        "positive": "Charged Pion Polarizability from the Lattice: Direct evaluation of charged particle polarizabilities on the lattice is\nquite difficult. However, a short cut for charged pion polarizability - the\nDas, Mathur, Okubo Sum Rule - can readily be calculated using lattice\ntechniques. A phenomenological model has been developed to fit the time\nbehavior of the propagators in this expression. Numerical systematics are\ndiscussed and some preliminary results are presented."
    },
    {
        "anchor": "Current Renormalization in Finite Volume: For finite volume field theories with discrete translational invariance,\nconserved currents can be additively renormalized by infrared effects. We\ndemonstrate this for pions using chiral perturbation theory coupled to\nelectromagnetism in a periodic box. Gauge invariant single particle effective\ntheories are constructed to explain these results. In such theories, current\nrenormalization arises from operators involving the zero mode of the gauge\nfield. No contradictions with Ward identities, or low-energy theorems are\nencountered.",
        "positive": "Aoki Phases in Staggered-Wilson Fermions: We investigate the parity-broken phase (Aoki phase) for staggered-Wilson\nfermions by using the Gross-Neveu model and the strong-coupling lattice QCD. In\nthe both cases the gap equations indicate the parity-broken phase exists and\nthe pion becomes massless on the phase boundaries. We also show we can take the\nchiral and continuum limit in the Gross-Neveu model by tuning mass and\ngauge-coupling parameters. This supports the idea that the staggered-Wilson\nfermions can be applied to the lattice QCD simulation by taking a chiral limit,\nas with Wilson fermions."
    },
    {
        "anchor": "Effective lattice Polyakov loop theory for finite temperature Yang-Mills: Effective Polyakov loop theories are a useful tool for an investigation of\npure Yang-Mills theory and full QCD. A systematic derivation of the effective\naction can be done in a spatial strong coupling expansion. Quite accurate\npredictions for the deconfinement phase transition of Yang-Mills theory have\nbeen obtained in this approach. Besides the critical couplings, further\nobservables can be measured in the effective theory. These provide additional\ntests for the reliability of the strong coupling approach and the truncation of\nthe effective action. In this contribution we will present recent results for\nthe free energy of the static quark-antiquark pair and the equation of state.",
        "positive": "Impact of Lattice QCD on CKM Phenomenology: Precise lattice QCD results for hadronic matrix elements, decay constants and\nform factors play a crucial role in the determination of CKM matrix elements\nand in the identification of possible new physics contributions to flavour\nviolating observables. This article reviews the implications of recent lattice\nQCD results on the phenomenology of flavour and CP violating meson decays, and\nhighlights some future directions for lattice QCD calculations which would have\na major impact on flavour phenomenology."
    },
    {
        "anchor": "The nature of the continuum limit in strongly coupled quenched QED: We review the results of large scale simulations of noncompact quenched $QED$\nwhich use spectrum and Equation of State calculations to determine the theory's\nphase diagram, critical indices, and continuum limit. The resulting anomalous\ndimensions are in good agreement with Schwinger-Dyson solutions of the ladder\ngraphs of conventional $QED$ and they satisfy the hyperscaling relations\nexpected of a relativistic renormalizable field theory. The spectroscopy\nresults satisfy the constraints of the Goldstone mechanism and PCAC, and may be\nindicative of Technicolor versions of the Standard Model which are strongly\ncoupled at short distances.",
        "positive": "The Phase Diagrams of the Schwinger and Gross-Neveu Models with Wilson\n  Fermions: A new method to analytically determine the partition function zeroes of\nweakly coupled theories on finite-size lattices is developed. Applied to the\nlattice Schwinger model, this reveals the possible absence of a phase\ntransition at fixed weak coupling. We show how finite-size scaling techniques\non small or moderate lattice sizes may mimic the presence of a spurious phase\ntransition. Application of our method to the Gross-Neveu model yields a phase\ndiagram consistent with that coming from a saddle point analysis."
    },
    {
        "anchor": "Eigenstates of the lattice RS model: For quantum field theories involving interaction between fermion and boson\nfields, the bare fermionic (bosonic) annihilation operators cannot annihilate\nthe vacuum state, and the bare fermionic (bosonic) creation operators cannot\ncreate fermionic (bosonic) one-particle states. The actual bosonic particles\ncontain fermion field components, and fermionic particles contain boson field\ncomponents, while the vacuum state exhibits entanglement between the fermion\nand boson fields. We utilize the lattice Rothe-Stamatescu (RS) model to\nnonperturbatively and directly demonstrate this field mixing. We provide the\nHamiltonian of the lattice RS model, calculate its correlation functions, and\nobserve that the correlation functions in the continuum limit recover those of\nthe original continuous RS model. Furthermore, we derive the equations of\nmotion for the lattice RS model and compare them to those of the original RS\nmodel. Instead of employing the traditional Fock representation commonly used\nin discussions of field mixing, we define a special representation to present\nthe vacuum state and one-particle states of the lattice RS model. These\neigenstates not only reveal the entanglement between the boson and fermion\nfields but also allow us to directly observe the spatial entanglement\nstructure.",
        "positive": "The Analytic Renormalization Group: Finite temperature Euclidean two-point functions in quantum mechanics or\nquantum field theory are characterized by a discrete set of Fourier\ncoefficients $G_{k}$, $k\\in\\mathbb Z$, associated with the Matsubara\nfrequencies $\\nu_{k}=2\\pi k/\\beta$. We show that analyticity implies that the\ncoefficients $G_{k}$ must satisfy an infinite number of model-independent\nlinear equations that we write down explicitly. In particular, we construct\n\"Analytic Renormalization Group\" linear maps $\\mathsf A_{\\mu}$ which, for any\nchoice of cut-off $\\mu$, allow to express the low energy Fourier coefficients\nfor $|\\nu_{k}|<\\mu$ (with the possible exception of the zero mode $G_{0}$),\ntogether with the real-time correlators and spectral functions, in terms of the\nhigh energy Fourier coefficients for $|\\nu_{k}|\\geq\\mu$. Operating a simple\nnumerical algorithm, we show that the exact universal linear constraints on\n$G_{k}$ can be used to systematically improve any random approximate data set\nobtained, for example, from Monte-Carlo simulations. Our results are\nillustrated on several explicit examples."
    },
    {
        "anchor": "Non-perturbative renormalization of flavor singlet quark bilinear\n  operators in lattice QCD: We report on our studies of the renormalization of flavor singlet quark\nbilinear operators in lattice QCD. The renormalization constants are determined\nnon-perturbatively using gauge field ensembles with Nf=2 dynamical clover\nimproved fermions. The renormalization is performed in the RI'-MOM scheme. The\ndifference between flavor singlet and non-singlet quark bilinear operators is a\ndisconnected contribution, which has to be evaluated by stochastic estimators.\nWe compare our results for the running with perturbation theory.",
        "positive": "Nucleon matrix elements with $N_f=2+1+1$ maximally twisted fermions: We present the first lattice calculation of nucleon matrix elements using\nfour dynamical flavors. We use the $N_f=2+1+1$ maximally twisted mass\nformulation. The renormalization is performed non-perturbatively in the\nRI$^\\prime$-MOM scheme and results are given for the vector and axial vector\noperators with up to one-derivative. Our calculation of the average momentum of\nthe unpolarized non-singlet parton distribution is presented and compared to\nour previous results obtained from the $N_f=2$ case."
    },
    {
        "anchor": "Algebraic Computation of the Hierarchical Renormalization Group Fixed\n  Points and their $\u03b5$-Expansions: Nontrivial fixed points of the hierarchical renormalization group are\ncomputed by numerically solving a system of quadratic equations for the\ncoupling constants. This approach avoids a fine tuning of relevant parameters.\nWe study the eigenvalues of the renormalization group transformation,\nlinearized around the non-trivial fixed points. The numerical results are\ncompared with $\\epsilon$-expansion.",
        "positive": "Finite-size scaling of interface free energies in the 3d Ising model: We perform a study of the universality of the finite size scaling functions\nof interface free energies in the 3d Ising model. Close to the hot/cold phase\ntransition, we observe very good agreement with the same scaling functions of\nthe 4d SU(2) Yang--Mills theory at the deconfinement phase transition."
    },
    {
        "anchor": "The QCD topological susceptibility at high temperatures via staggered\n  fermions spectral projectors: The QCD topological observables are essential inputs to obtain theoretical\npredictions about axion phenomenology, which are of utmost importance for\ncurrent and future experimental searches for this particle. Among them, we\nfocus on the topological susceptibility, related to the axion mass. We present\nlattice results for the topological susceptibility in QCD at high temperatures\nobtained by discretizing this observable via spectral projectors on eigenmodes\nof the staggered Dirac operator, and we compare them with those obtained with\nthe standard gluonic definition. The adoption of the spectral discretization is\nmotivated by the large lattice artifacts affecting the standard gluonic\nsusceptibility, related to the choice of non-chiral fermions in the lattice\naction.",
        "positive": "Numerical techniques for lattice QCD in the $\u03b5$--regime: In lattice QCD it is possible, in principle, to determine the parameters in\nthe effective chiral lagrangian (including weak interaction couplings) by\nperforming numerical simulations in the $\\epsilon$--regime, i.e. at quark\nmasses where the physical extent of the lattice is much smaller than the\nCompton wave length of the pion. The use of a formulation of the lattice theory\nthat preserves chiral symmetry is attractive in this context, but the numerical\nimplementation of any such approach requires special care in this kinematical\nsituation due to the presence of some very low eigenvalues of the Dirac\noperator. We discuss a set of techniques (low-mode preconditioning and\nadapted-precision algorithms in particular) that make such computations\nnumerically safe and more efficient by a large factor."
    },
    {
        "anchor": "Critical Exponents of the Classical 3D Heisenberg Model: A\n  Single-Cluster Monte Carlo Study: We have simulated the three-dimensional Heisenberg model on simple cubic\nlattices, using the single-cluster Monte Carlo update algorithm. The expected\npronounced reduction of critical slowing down at the phase transition is\nverified. This allows simulations on significantly larger lattices than in\nprevious studies and consequently a better control over systematic errors. In\none set of simulations we employ the usual finite-size scaling methods to\ncompute the critical exponents $\\nu,\\alpha,\\beta,\\gamma, \\eta$ from a few\nmeasurements in the vicinity of the critical point, making extensive use of\nhistogram reweighting and optimization techniques. In another set of\nsimulations we report measurements of improved estimators for the spatial\ncorrelation length and the susceptibility in the high-temperature phase,\nobtained on lattices with up to $100^3$ spins. This enables us to compute\nindependent estimates of $\\nu$ and $\\gamma$ from power-law fits of their\ncritical divergencies.",
        "positive": "Calculation of connected contributions to the S-matrix using duality\n  between lattice theories: The main aim of this work - to calculate 2- and 4-point connected\ncontributions to the $S$-matrix and correlation functions for the euclidean\nscalar field on the lattice with self-action $|\\phi|^{n}$ for $n>2$ with\ncoupling constant renormalised in a special way for arbitrary dimension. It is\nshown that the considered theory has a nontrivial continuous limit. A new\nmethod is proposed without the use of perturbation theory and diagrams. We have\nused the explored duality between different lattice field theories. After its\napplication, it turns out that it is possible to apply the saddle-point method\nto the generating functional, where the concentration of nodes of the initial\nlattice approximation acts as a large parameter. In addition to the connected\ncontributions to the $S$-matrix, the beta function is calculated. We have found\na critical point for the theory of $\\phi^{4k}$ in arbitrary dimension and a\nnontrivial mass gap of the interacting massless theory. We have received the\nmasses of bound and single-particle states of the interacting theory. The\nproposed method can be extend for application to QED and gauge theories, as\nwell as generalized to the arbitrary geometry of space. Though the way of\ncoupling rescaling is specific, it gives nontrivial theory with the majority of\nperturbatively expected effects."
    },
    {
        "anchor": "Lattice QCD and the Balkan physicists contribution: This is a paper based on the invited talk the author gave at the 9th Balkan\nPhysical Union conference. It contains some of the main achievements of lattice\nQCD simulations followed by a list of Balkan physicists who have contributed to\nthe project.",
        "positive": "Domain wall fermions in a waveguide: the phase diagram at large Yukawa\n  coupling: In this paper we return to a model with domain wall fermions in a waveguide.\nThis model contains a Yukawa coupling $y$ which is needed for gauge invariance.\nA previous paper left the analysis for large values of this coupling\nincomplete. We fill the gap by developing a systematic expansion suitable for\nlarge $y$, and using this, we gain an analytic understanding of the phase\ndiagram and fermion spectrum. We find that in a sense all the species doublers\ncome back for large $y$. The conclusion that no lattice chiral gauge theory can\nbe obtained from this approach therefore remains valid."
    },
    {
        "anchor": "Massive gluon propagator at zero and finite temperature: We report on our study of the infrared gluon propagator for SU(2) lattice\ngauge theory using large lattice volumes. The observed massive behavior is\ndiscussed from the point of view of analytic predictions for the\nzero-temperature case. Such a behavior is still present as the temperature is\nswitched on, but manifests itself differently in the electric and magnetic\nchannels.",
        "positive": "Topology of Boundary Surfaces in 3D Simplicial Gravity: A model of simplicial quantum gravity in three dimensions(3D) was\ninvestigated numerically based on the technique of dynamical triangulation\n(DT). We are concerned with the genus of surfaces appearing on boundaries\n(i.e., sections) of a 3D DT manifold with $S^{3}$ topology. Evidence of a\nscaling behavior of the genus distributions of boundary surfaces has been\nfound."
    },
    {
        "anchor": "Complex Paths Around The Sign Problem: The Monte Carlo evaluation of path integrals is one of a few general purpose\nmethods to approach strongly coupled systems. It is used in all branches of\nPhysics, from QCD/nuclear physics to the correlated electron systems. However,\nmany systems of great importance (dense matter inside neutron stars, the\nrepulsive Hubbard model away from half-filling, dynamical and non-equilibrium\nobservables) are not amenable to the Monte Carlo method as it currently stands\ndue to the so-called \"sign-problem\". We review a new set of ideas recently\ndeveloped to tackle the sign problem based on the complexification of field\nspace and the Picard-Lefshetz theory accompanying it. The mathematical ideas\nunderpinning this approach, as well as the algorithms so far developed, are\ndescribed together with non-trivial examples where the method has already been\nproved successful. Directions of future work, including the burgeoning use of\nmachine learning techniques, are delineated.",
        "positive": "Charting the scaling region of the Ising universality class in two and\n  three dimensions: We study the behaviour of a universal combination of susceptibility and\ncorrelation length in the Ising model in two and three dimensions, in presence\nof both magnetic and thermal perturbations, in the neighbourhood of the\ncritical point. In three dimensions we address the problem using a parametric\nrepresentation of the equation of state. In two dimensions we make use of the\nexact integrability of the model along the thermal and the magnetic axes. Our\nresults can be used as a sort of \"reference frame\" to chart the critical region\nof the model. While our results can be applied in principle to any possible\nrealization of the Ising universality class, we address in particular, as\nspecific examples, three instances of Ising behaviour in finite temperature QCD\nrelated in various ways to the deconfinement transition. In particular, in the\nlast of these examples, we study the critical ending point in the finite\ndensity, finite temperature phase diagram of QCD. In this finite density\nframework, due to well know sign problem, Montecarlo simulations are not\npossible and thus a direct comparison of experimental results with QFT/Statmech\npredictions like the one we discuss in this paper may be important. Moreover in\nthis example it is particularly difficult to disentangle \"magnetic-like\" from\n\"thermal-like\" observables and thus universal quantities which do not need a\nprecise identification of the magnetic and thermal axes, like the one we\naddress in this paper, can be particularly useful."
    },
    {
        "anchor": "Multi-bosonic algorithms for dynamical fermion simulations: Multi-bosonic fermion simulation algorithms are reviewed, with particular\nemphasis on a recent application in SU(2) Yang-Mills theory with light gluinos.",
        "positive": "Static Potential At Non-zero Temperatures From Fine Lattices: We report on a preliminary study of static quark anti-quark potential at\nnon-zero temperature in $2+1$ flavor QCD using $96^3\\times N_{\\tau}$ lattices\nwith lattice spacing $a=0.028$fm, physical strange quark mass and light quark\nmasses corresponding to pion mass of about $300$ MeV. We use\n$N_\\tau=32,~24,~20$ and $16$ that correspond to temperature range $T=220-441$\nMeV. The in order to obtain the potential we calculate the Wilson line\ncorrelator in Coulomb gauge with additional HYP smearing to reduce the noise at\nlarge quark anti-quark separations. We apply $0$, $5$ and $10$ steps of HYP\nsmearing to ensure that there is no physical effect from over-smearing. At the\ntwo highest temperatures we also consider a noise reduction technique that is\nbased on an interpolation in the spatial separation between the static quark\nand anti-quark."
    },
    {
        "anchor": "Glueball and gluelump spectrum in abelian projected QCD: We study glueball and gluelump spectra calculated after abelian projection in\nboth quenched and $N_f=2$ full QCD. The abelian projection is made after MA\ngauge fixing. We demonstrate that both spectra can be recovered despite the\nproblem with positivity. We suggest the interpretation of some of the gluelump\nstates in the language of the abelian projected theory.",
        "positive": "Precision computation of a low-energy reference scale in quenched\n  lattice QCD: We present results for the reference scale r_0 in SU(3) Lattice Gauge Theory\nfor beta = 6/g_0^2 in the range 5.7 <= beta <= 6.57. The high relative accuracy\nof 0.3-0.6% in r_0/a was achieved through good statistics, the application of a\nmulti-hit procedure and a variational approach in the computation of Wilson\nloops. A precise definition of the force used to extract r_0 has been used\nthroughout the calculation which guarantees that r_0/a is a smooth function of\nthe bare coupling and that subsequent continuum extrapolations are possible.\nThe results are applied to the continuum extrapolations of the energy gap Delta\nin the static quark potential and the scale L_max/r_0 used in the calculation\nof the running coupling constant."
    },
    {
        "anchor": "Confronting Instanton Perturbation Theory with QCD Lattice Results: We exploit a recent lattice investigation (UKQCD) on the topological\nstructure of the (quenched) QCD vacuum, in order to gain information on crucial\nbuilding blocks of instanton perturbation theory. A central motivation is to\nfurther constrain our previous predictions of instanton-induced hard scattering\nprocesses. First, we address the generic problem of extracting quantitative\ninformation from cooled lattice data. We find a new scaling variable,\ninterpreted as a \"cooling radius\", which allows to combine lattice data for a\nwhole range of lattice spacings and cooling sweeps. This variable strongly\nhelps to extract information on the uncooled distributions of interest. After\nperforming the continuum extrapolation of the instanton size and\ninstanton-anti-instanton distance distributions, we find striking agreement\nwith the theoretical predictions from instanton-perturbation theory, for\ninstanton sizes below 0.5 fm and distances above 0.5 fm, respectively. These\nresults imply first direct support for the validity of the known valley\ninteraction between instantons and anti-instantons.",
        "positive": "Light Baryons from 2+1 flavor DWF QCD: We present results from the RBC and UKQCD collaboration ensembles of 2+1\nflavor DWF QCD for the light baryon spectrum."
    },
    {
        "anchor": "Schwinger Model Mass Anomalous Dimension: The mass anomalous dimension for several gauge theories with an infrared\nfixed point has recently been determined using the mode number of the Dirac\noperator. In order to better understand the sources of systematic error in this\nmethod, we apply it to a simpler model, the massive Schwinger model with two\nflavours of fermions, where analytical results are available for comparison\nwith the lattice data.",
        "positive": "Theoretical and Computational Aspects of New Lattice Fermion\n  Formulations: In this work we investigate theoretical and computational aspects of novel\nlattice fermion formulations for the simulation of lattice gauge theories. The\nlattice approach to quantum gauge theories is an important tool for studying\nquantum chromodynamics, where it is the only known framework for calculating\nphysical observables from first principles. In our investigations we focus on\nstaggered Wilson fermions and the related staggered domain wall and staggered\noverlap formulations. Originally proposed by Adams, these new fermion\ndiscretizations bear the potential to reduce the computational costs of\nstate-of-the-art Monte Carlo simulations. Staggered Wilson fermions combine\naspects of both staggered and Wilson fermions while having a reduced number of\nfermion doublers compared to usual staggered fermions. Moreover, they can be\nused as a kernel operator for the domain wall fermion construction with\npotentially significantly improved chiral properties and for the overlap\noperator with its exact chiral symmetry. This allows the implementation of\nchirality on the lattice in a controlled manner at potentially significantly\nreduced costs. The practical potential and limitations of these new lattice\nfermions are also critically discussed."
    },
    {
        "anchor": "Adjoint SU(2) with Four Fermion Interactions: Four fermion interactions appear in many models of Beyond Standard Model\nphysics. In Technicolour and composite Higgs models Standard Model fermion\nmasses can be generated by four fermion terms. They are also expected to modify\nthe dynamics of the new strongly interacting sector. In particular in\ntechnicolour models it has been suggested that they can be used to break\ninfrared conformality and produce a walking theory with a large mass anomalous\ndimension. We study the SU(2) gauge theory with 2 adjoint fermions and a\nchirally symmetric four fermion term. We demonstrate chiral symmetry breaking\nat large four fermion coupling and study the phase diagram of the model.",
        "positive": "Can a Linear Sigma Model Describe Walking Gauge Theories at Low\n  Energies?: In recent years, many investigations of confining Yang Mills gauge theories\nnear the edge of the conformal window have been carried out using lattice\ntechniques. These studies have revealed that the spectrum of hadrons in nearly\nconformal (\"walking\") gauge theories differs significantly from the QCD\nspectrum. In particular, a light flavorsinglet scalar appears in the spectrum\nwhich is nearly degenerate with the pseudo-NambuGoldstone bosons (PNGBs) at the\nlightest currently accessible quark masses. This state is a viable candidate\nfor a composite Higgs boson. Presently, an acceptable effective field theory\n(EFT) description of the light states in walking theories has not been\nestablished. Such an EFT would be useful for performing chiral extrapolations\nof lattice data and for serving as a bridge between lattice calculations and\nphenomenology. It has been shown that the chiral Lagrangian fails to describe\nthe IR dynamics of a theory near the edge of the conformal window. Here we\nassess a linear sigma model as an alternate EFT description by performing\nexplicit chiral fits to lattice data. Our model provides an acceptable combined\nfit to the PNGB mass and decay constant, reducing the $\\chi^2$/d.o.f. by more\nthan an order of magnitude compared to next-to-leading order chiral\nperturbation theory."
    },
    {
        "anchor": "On the effects of (partial) quenching on penguin contributions to K-> pi\n  pi: Recently, we pointed out that chiral transformation properties of strong\npenguin operators change in the transition from unquenched to (partially)\nquenched QCD. As a consequence, new penguin-like operators appear in the\n(partially) quenched theory, along with new low-energy constants, which should\nbe interpreted as a quenching artifact. Here, we extend the analysis to the\ncontribution of the new low-energy constants to the K^0 -> pi^+ pi^- amplitude,\nat leading order in chiral perturbation theory, and for arbitrary (momentum\nnon-conserving) kinematics. Using these results, we provide a detailed\ndiscussion of the intrinsic systematic error due to this (partial) quenching\nartifact. We also give a simple recipe for the determination of the\nleading-order low-energy constant parameterizing the new operators in the case\nof strong $LR$ penguins.",
        "positive": "Nucleon excited states on the lattice: We study the pion-nucleon system in s-wave in the framework of lattice QCD in\norder to gain new information on the nucleon excited states. We perform\nsimulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266\nMeV. The results show that including the two-particle states drastically\nchanges the energy levels. The variational analysis and the distillation\napproach play an important role in the extraction of the energy levels. The\nphase shift analysis allows to extract information on the resonance nature of\nthe observed states."
    },
    {
        "anchor": "New findings for topological excitations in SU(3) lattice gauge theory: We probe the SU(3) vacuum using eigenvectors of the Dirac operator with an\narbitrary phase for the temporal boundary condition. We consider configurations\nwith topological charge |Q| = 1 near the QCD phase transition and at low\ntemperatures on a torus. For all our ensembles we show that the zero-mode of\nthe Dirac operator changes its position as one changes the phase of the\nboundary condition. For ensembles near the QCD phase transition our results\nclosely resemble the behavior of zero-modes for Kraan - van Baal solutions of\nthe classical Yang-Mills equations where the individual lumps are interpreted\nas monopoles. Our findings near T_c and on the torus show that for both cases\nan excitation with topological charge |Q| = 1 is built from several separate\nlumps.",
        "positive": "Two-point functions of quenched lattice QCD in Numerical Stochastic\n  Perturbation Theory: We summarize the higher-loop perturbative computation of the ghost and gluon\npropagators in SU(3) Lattice Gauge Theory. Our final aim is to compare with\nresults from lattice simulations in order to expose the genuinely\nnon-perturbative content of the latter. By means of Numerical Stochastic\nPerturbation Theory we compute the ghost and gluon propagators in Landau gauge\nup to three and four loops. We present results in the infinite volume and $a\n\\to 0$ limits, based on a general fitting strategy."
    },
    {
        "anchor": "Dynamical QCD thermodynamics with domain wall fermions: We present results from numerical simulations of full, two flavor QCD\nthermodynamics at N_t=4 with domain wall fermions. For the first time a\nnumerical simulation of the full QCD phase transition displays a low\ntemperature phase with spontaneous chiral symmetry breaking but intact flavor\nsymmetry and a high temperature phase with the full SU(2) x SU(2) chiral flavor\nsymmetry.",
        "positive": "Analytic continuation of the finite-volume three-particle amplitudes: One has to study multivariable scattering amplitudes to extract properties of\nthe three-body states from the generalizations of the L\\\"uscher finite-volume\nformalism. In particular, a three-body amplitude obtained from a Lattice QCD\ncalculation must be analytically continued to unphysical Riemann sheets of the\ncomplex energy plane, where resonances of interest appear as poles. In this\narticle, we provide a pedagogical overview of a method for solving and\nanalytically continuing the on-shell integral equations describing a three-body\nelastic scattering process. We illustrate the procedure by applying it to a\nrelativistic system of three identical bosons characterized by pair-wise\ninteractions. We describe the analytic structure of the reaction amplitude,\nshow how to access its physical and unphysical Riemann sheets, and analyze the\nbehavior of the three-body spectrum under variations of the interaction\nparameters."
    },
    {
        "anchor": "Decay constants of charm and beauty pseudoscalar heavy-light mesons on\n  fine lattices: We compute decay constants of heavy-light mesons in quenched lattice QCD with\na lattice spacing of a ~ 0.04 fm using non-perturbatively O(a) improved Wilson\nfermions and O(a) improved currents. We obtain f_{D_s} = 220(6)(5)(11) MeV, f_D\n= 206(6)(3)(22) MeV, f_{B_s} = 205(7)(26)(17) MeV and f_B = 190(8)(23)(25) MeV,\nusing the Sommer parameter r_0 = 0.5 fm to set the scale. The first error is\nstatistical, the second systematic and the third from assuming a +-10%\nuncertainty in the experimental value of r_0. A detailed discussion is given in\nthe text. We also present results for the meson decay constants f_K and f_\\pi\nand the \\rho meson mass.",
        "positive": "First results with twisted mass fermions towards the computation of\n  parton distribution functions on the lattice: We report on our exploratory study for the evaluation of the parton\ndistribution functions from lattice QCD, based on a new method proposed in\nRef.~arXiv:1305.1539. Using the example of the nucleon, we compare two\ndifferent methods to compute the matrix elements needed, and investigate the\napplication of gauge link smearing. We also present first results from a large\nproduction ensemble and discuss the future challenges related to this method."
    },
    {
        "anchor": "Critical Behavior of a Chiral Condensate with a Meron Cluster Algorithm: A new meron cluster algorithm is constructed to study the finite temperature\ncritical behavior of the chiral condensate in a $(3+1)$ dimensional model of\ninteracting staggered fermions. Using finite size scaling analysis the infinite\nvolume condensate is shown to be consistent with the behavior of the form\n$(T_c-T)^{0.314(7)}$ for temperatures less than the critical temperature and\n$m^{1/4.87(10)}$ at the critical temperature confirming that the critical\nbehavior belongs to the 3-d Ising universality class within one to two sigma\ndeviation. The new method, along with improvements in the implementation of the\nalgorithm, allows the determination of the critical temperature $T_c$ more\naccurately than was possible in a previous study.",
        "positive": "High-Accuracy Calculations of the Critical Exponents of Dyson's\n  Hierarchical Model: We calculate the critical exponent gamma of Dyson's hierarchical model by\ndirect fits of the zero momentum two-point function, calculated with an Ising\nand a Landau-Ginzburg measure, and by linearization about the Koch-Wittwer\nfixed point. We find gamma= 1.299140730159 plus or minus 10^(-12). We extract\nthree types of subleading corrections (in other words, a parametrization of the\nway the two-point function depends on the cutoff) from the fits and check the\nvalue of the first subleading exponent from the linearized procedure. We\nsuggest that all the non-universal quantities entering the subleading\ncorrections can be calculated systematically from the non-linear contributions\nabout the fixed point and that this procedure would provide an alternative way\nto introduce the bare parameters in a field theory model."
    },
    {
        "anchor": "Meson Form-factors and Wave-functions with Wilson fermions: Results for semi-leptonic form-factors for processes like $D \\to K l \\nu$ and\nthe Bethe-Salpeter amplitudes (BSA) for pion and rho mesons are presented. The\nform-factor data is consistent with previous calculations. We find that the\nlong distance fall-off of BSA for both $\\pi$ and $\\rho$ is very well fit by an\nexponential, but surprisingly the effective mass governing this fall-off is\nlighter than the pion's. Lastly, by studying the dependence of $\\rho$\npolarization on separation direction we show that there is a measureable $l=2$\nstate in addition to $l=0$ in the BSA for the rho. (Talk presented by R. Gupta\nat LATTICE92. Latex needs macro package espcrc2.sty)",
        "positive": "Nucleon scalar and tensor charges using lattice QCD simulations at the\n  physical value of the pion mass: We present results on the light, strange and charm nucleon scalar and tensor\ncharges from lattice QCD, using simulations with $N_f=2$ flavors of twisted\nmass Clover-improved fermions with a physical value of the pion mass. Both\nconnected and disconnected contributions are included, enabling us to extract\nthe isoscalar, strange and charm charges for the first time directly at the\nphysical point. Furthermore, the renormalization is computed non-perturbatively\nfor both isovector and isoscalar quantities. We investigate excited state\neffects by analyzing several sink-source time separations and by employing a\nset of methods to probe ground state dominance. Our final results for the\nscalar charges are $g_S^u = 5.20(42)(15)(12)$, $g_S^d = 4.27(26)(15)(12)$,\n$g_S^s=0.33(7)(1)(4)$, $g_S^c=0.062(13)(3)(5)$ and for the tensor charges\n$g_T^u = 0.782(16)(2)(13)$, $g_T^d = -0.219(10)(2)(13)$,\n$g_T^s=-0.00319(69)(2)(22)$, $g_T^c=-0.00263(269)(2)(37)$ in the $\\overline{\\rm\nMS}$ scheme at 2~GeV. The first error is statistical, the second is the\nsystematic error due to the renormalization and the third the systematic\narising from possible contamination due to the excited states."
    },
    {
        "anchor": "Autocorrelations in Hybrid Monte Carlo Simulations: Simulations of QCD suffer from severe critical slowing down towards the\ncontinuum limit. This problem is known to be prominent in the topological\ncharge, however, all observables are affected to various degree by these slow\nmodes in the Monte Carlo evolution. We investigate the slowing down in high\nstatistics simulations and propose a new error analysis method, which gives a\nrealistic estimate of the contribution of the slow modes to the errors.",
        "positive": "Numerical Methods for the QCD Overlap Operator:III. Nested Iterations: The numerical and computational aspects of chiral fermions in lattice quantum\nchromodynamics are extremely demanding. In the overlap framework, the\ncomputation of the fermion propagator leads to a nested iteration where the\nmatrix vector multiplications in each step of an outer iteration have to be\naccomplished by an inner iteration; the latter approximates the product of the\nsign function of the hermitian Wilson fermion matrix with a vector. In this\npaper we investigate aspects of this nested paradigm. We examine several Krylov\nsubspace methods to be used as an outer iteration for both propagator\ncomputations and the Hybrid Monte-Carlo scheme. We establish criteria on the\naccuracy of the inner iteration which allow to preserve an a priori given\nprecision for the overall computation. It will turn out that the accuracy of\nthe sign function can be relaxed as the outer iteration proceeds. Furthermore,\nwe consider preconditioning strategies, where the preconditioner is built upon\nan inaccurate approximation to the sign function. Relaxation combined with\npreconditioning allows for considerable savings in computational efforts up to\na factor of 4 as our numerical experiments illustrate. We also discuss the\npossibility of projecting the squared overlap operator into one chiral sector."
    },
    {
        "anchor": "Singlet vs Nonsinglet Perturbative Renormalization of Fermion Bilinears: In this paper we present the perturbative evaluation of the difference\nbetween the renormalization functions of flavor singlet and nonsinglet bilinear\nquark operators on the lattice. The computation is performed to two loops and\nto lowest order in the lattice spacing, for a class of improved lattice\nactions, including Wilson, tree-level (TL) Symanzik and Iwasaki gluons, twisted\nmass and SLiNC Wilson fermions, as well as staggered fermions with twice\nstout-smeared links. In the staggered formalism, the stout smearing procedure\nis also applied to the definition of bilinear operators.",
        "positive": "Spectral density of the Hermitean Wilson Dirac operator: a NLO\n  computation in chiral perturbation theory: We compute the lattice spacing corrections to the spectral density of the\nHermitean Wilson Dirac operator using Wilson Chiral Perturbation Theory at NLO.\nWe consider a regime where the quark mass $m$ and the lattice spacing $a$ obey\nthe relative power counting $m\\sim a \\Lambda_{\\rm QCD}^2$: in this situation\ndiscretisation effects can be treated as perturbation of the continuum\nbehaviour. While this framework fails to describe lattice spectral density\nclose to the threshold, it allows nevertheless to investigate important\nproperties of the spectrum of the Wilson Dirac operator. We discuss the range\nof validity of our results and the possible implications in understanding the\nphase diagram of Wilson fermions."
    },
    {
        "anchor": "Meson masses in electromagnetic fields with Wilson fermions: We determine the light meson spectrum in QCD in the presence of background\nmagnetic fields using quenched Wilson fermions. Our continuum extrapolated\nresults indicate a monotonous reduction of the connected neutral pion mass as\nthe magnetic field grows. The vector meson mass is found to remain nonzero, a\nfinding relevant for the conjectured $\\rho$-meson condensation at strong\nmagnetic fields. The continuum extrapolation was facilitated by adding a novel\nmagnetic field-dependent improvement term to the additive quark mass\nrenormalization. Without this term, sizable lattice artifacts that would\ndeceptively indicate an unphysical rise of the connected neutral pion mass for\nstrong magnetic fields are present. We also investigate the impact of these\nlattice artifacts on further observables like magnetic polarizabilities and\ndiscuss the magnetic field-induced mixing between $\\rho$-mesons and pions. We\nalso derive Ward-Takashi identities for QCD+QED both in the continuum\nformulation and for (order $a$-improved) Wilson fermions.",
        "positive": "Interplay between Deconfinement and Chiral Properties: We study interplay between confinement/deconfinement and chiral properties.\nWe derive some analytical relations of the Dirac modes with the confinement\nquantities, such as the Polyakov loop, its susceptibility and the string\ntension. For the confinement quantities, the low-lying Dirac eigenmodes are\nfound to give negligible contribution, while they are essential for chiral\nsymmetry breaking. This indicates no direct, one-to-one correspondence between\nconfinement/deconfinement and chiral properties in QCD. We also investigate the\nPolyakov loop in terms of the eigenmodes of the Wilson, the clover and the\ndomain-wall fermion kernels, respectively."
    },
    {
        "anchor": "A massive momentum-subtraction scheme: A new renormalization scheme is defined for fermion bilinears in QCD at non\nvanishing quark masses. This new scheme, denoted RI/mSMOM, preserves the\nbenefits of the nonexceptional momenta introduced in the RI/SMOM scheme, and\nallows a definition of renormalized composite fields away from the chiral\nlimit. Some properties of the scheme are investigated by performing explicit\none-loop computation in dimensional regularization.",
        "positive": "Anisotropic Gauge Theories: A Numerical Study of the Fu-Nielsen Model: We study numerically 4+1 dimensional pure gauge theory."
    },
    {
        "anchor": "Charmed baryons at the physical point in 2+1 flavor lattice QCD: We investigate the charmed baryon mass spectrum using the relativistic heavy\nquark action on 2+1 flavor PACS-CS configurations previously generated on $32^3\n\\times 64$ lattice. The dynamical up-down and strange quark masses are tuned to\ntheir physical values, reweighted from those employed in the configuration\ngeneration. At the physical point, the inverse lattice spacing determined from\nthe $\\Omega$ baryon mass gives $a^{-1}=2.194(10)$ GeV, and thus the spatial\nextent becomes $L = 32 a = 2.88(1)$ fm. Our results for the charmed baryon\nmasses are consistent with experimental values, except for the mass of\n$\\Xi_{cc}$, which has been measured by only one experimental group so far and\nhas not been confirmed yet by others. In addition, we report values of other\ndoubly and triply charmed baryon masses, which have never been measured\nexperimentally.",
        "positive": "Conformal perturbation description of deconfinement: Conformal perturbation theory is a powerful tool to describe the behavior of\nstatistical-mechanics models and quantum field theories in the vicinity of a\ncritical point. In the past few years, it has been extensively used to describe\ntwo-dimensional models and recently has also been extended to three-dimensional\nmodels. We show here that it can also be used to describe the behavior of\nfour-dimensional lattice gauge theories in the vicinity of a critical point. As\nan example, we discuss the two-point correlator of Polyakov loops close to the\nthermal deconfinement transition of $SU(2)$ Yang-Mills theory. We show that the\nshort-distance behavior of this correlation function (and, thus, of the\ninterquark potential) is described very well by conformal perturbation theory.\nThis method is expected to work with a similarly high accuracy for all critical\npoints in the same universality class, including, in particular, the critical\nendpoint in the QCD phase diagram."
    },
    {
        "anchor": "Exotic and higher spin mesons in the charmonium: Exotic and higher spin (> 1) mesons are still not throughly investigated in\nlattice QCD. Using a set of derivative based operators we report our\nexploratory study of these mesons in charmonium region. We use a 12^3 X 48\nanisotropic (xi = 3) clover lattice with inverse temporal lattice spacing a^-1\n= 6.05 GeV. Techniques developed in this exploratory study will be utilized in\nour future comprehensive study of light hybrid mesons that are to be explored\nin the 12 GeV GlueX experiment at Jefferson Laboratory.",
        "positive": "Thermal Monopole Condensation and Confinement in finite temperature\n  Yang-Mills Theories: We investigate the connection between Color Confinement and thermal Abelian\nmonopoles populating the deconfined phase of SU(2) Yang-Mills theory, by\nstudying how the statistical properties of the monopole ensemble change as the\nconfinement/deconfinement temperature is approached from above. In particular\nwe study the distribution of monopole currents with multiple wrappings in the\nEuclidean time direction, corresponding to two or more particle permutations,\nand show that multiple wrappings increase as the deconfinement temperature is\napproached from above, in a way compatible with a condensation of such objects\nhappening right at the deconfining transition. We also address the question of\nthe thermal monopole mass, showing that different definitions give consistent\nresults only around the transition, where the monopole mass goes down and\nbecomes of the order of the critical temperature itself."
    },
    {
        "anchor": "Simulating the weak death of the neutron in a femtoscale universe with\n  near-Exascale computing: The fundamental particle theory called Quantum Chromodynamics (QCD) dictates\neverything about protons and neutrons, from their intrinsic properties to\ninteractions that bind them into atomic nuclei. Quantities that cannot be fully\nresolved through experiment, such as the neutron lifetime (whose precise value\nis important for the existence of light-atomic elements that make the sun shine\nand life possible), may be understood through numerical solutions to QCD. We\ndirectly solve QCD using Lattice Gauge Theory and calculate nuclear observables\nsuch as neutron lifetime. We have developed an improved algorithm that\nexponentially decreases the time-to solution and applied it on the new CORAL\nsupercomputers, Sierra and Summit. We use run-time autotuning to distribute GPU\nresources, achieving 20% performance at low node count. We also developed\noptimal application mapping through a job manager, which allows CPU and GPU\njobs to be interleaved, yielding 15% of peak performance when deployed across\nlarge fractions of CORAL.",
        "positive": "Improved Fermion Hamiltonians for Quantum Simulation: We developed a Hamiltonian inspired by ASQTAD and highly improved staggered\nquark (HISQ) actions and show how these Hamiltonians can be used for quantum\nsimulations. Gate costs for the time evolution of these improved Hamiltonians\nare provided as well as a demonstration of the reduction of lattice spacing\nerrors using the 1+1d lattice Schwinger model."
    },
    {
        "anchor": "Quark masses with Nf=2 twisted mass lattice QCD: We present the results of the recent high precision lattice calculation of\nthe average up/down, strange and charm quark masses performed by ETMC with Nf=2\ntwisted mass Wilson fermions. The analysis includes data at four values of the\nlattice spacing and pion masses as low as ~270 MeV, allowing for accurate\ncontinuum limit and chiral extrapolation. The strange and charm masses are\nextracted by using several methods, based on different observables: the kaon\nand the eta_s meson for the strange quark and the D, D_s and eta_c mesons for\nthe charm. The quark mass renormalization is carried out non-perturbatively\nusing the RI-MOM method. The results for the quark masses in the MSbar scheme\nread: m_ud(2 GeV)= 3.6(2) MeV, m_s(2 GeV)=95(6) MeV and m_c(m_c)=1.28(4) GeV.\nWe have also obtained the ratios m_s/m_ud=27.3(9) and m_c/m_s=12.0(3).\nMoreover, we provide the updated result for the bottom quark mass,\nm_b(m_b)=4.3(2) GeV, obtained using the method presented in 0909.3187\n[hep-lat].",
        "positive": "Comparison between Theoretical Four-Loop Predictions and Monte Carlo\n  Calculations in the Two-Dimensional $N$-Vector Model for $N=3,4,8$: We have computed the four-loop contribution to the beta-function and to the\nanomalous dimension of the field for the two-dimensional lattice $N$-vector\nmodel. This allows the determination of the second perturbative correction to\nvarious long-distance quantities like the correlation lengths and the\nsusceptibilities. We compare these predictions with new Monte Carlo data for $N\n= 3,4,8$. From these data we also extract the values of various universal\nnonperturbative constants, which we compare with the predictions of the $1/N$\nexpansion."
    },
    {
        "anchor": "Kramers Equation Algorithm with Kogut-Susskind Fermions on Lattice: We compare the performance of the Kramers Equation Monte Carlo (KMC)\nAlgorithm with that of the Hybrid Monte Carlo (HMC) algorithm for numerical\nsimulations with dynamical Kogut-Susskind fermions. Using the lattice\nGross-Neveu model in 2 space-time dimensions, we calculate the integrated\nautocorrelation time of different observables at a number of couplings in the\nscaling region on 16^2 and 32^2 lattices while varying the parameters of the\nalgorithms for optimal performance. In our investigation the performance of KMC\nis always significantly below than that of HMC for the observables used. We\nalso stress the importance of having a large number of configurations for the\naccurate estimation of the integrated autocorrelation time.",
        "positive": "Gauge invariant investigation of the nature of Confinement: We observe a strong correlation between the decrease in the number of action\ndensity peaks in SU(2) Yang-Mills configurations with cooling and that of the\nstring tension. The nature and distribution of these peaks is investigated. The\nrelationship with monopole currents after the abelian projection is also\nconsidered."
    },
    {
        "anchor": "Fourier acceleration, the HMC algorithm and renormalizability: The analysis developed by L\\\"uscher and Schaefer of the Hybrid Monte Carlo\n(HMC) algorithm is extended to include Fourier acceleration. We show for the\n$\\phi^4$ theory that Fourier acceleration substantially changes the structure\nof the theory for both the Langevin and HMC algorithms. When expanded in\nperturbation theory, each five-dimensional auto-correlation function of the\nfields $\\phi(x_i, t_i)$, $1\\le i \\le N $, corresponding to a specific\n4-dimensional Feynman graph separates into two factors: one depending on the\nMonte-Carlo evolution times $t_i$ and the second depending on the space-time\npositions $x_i$. This separation implies that only auto-correlation times at\nthe lattice scale appear, eliminating critical slowing down in perturbation\ntheory.",
        "positive": "Towards a Dual Representation of Lattice QCD: Our knowledge about the QCD phase diagram at finite baryon chemical potential\n$\\mu_{B}$ is limited by the well known sign problem. The path integral measure,\nin the standard determinantal approach, becomes complex at finite $\\mu_{B}$ so\nthat standard Monte Carlo techniques cannot be directly applied. As the sign\nproblem is representation dependent, by a suitable choice of the fundamental\ndegrees of freedom that parameterize the partition function, it can get mild\nenough so that reweighting techniques can be used. A successful formulation,\ncapable to tame the sign problem, is known since decades in the limiting case\n$\\beta\\to 0$, where performing the gauge integration first, gives rise to a\ndual formulation in terms of color singlets (MDP formulation). Going beyond the\nstrong coupling limit represents a serious challenge as the gauge integrals\ninvolved in the computation are only partially known analytically and become\nstrongly coupled for $\\beta>0$. We will present explict formulae for all the\nintegral relevant for ${\\rm SU}(N)$ gauge theories discretised \\`a la Wilson,\nand will discuss how they can be used to obtain a positive dual formulation,\nvalid for all $\\beta$, for pure Yang Mills theory."
    },
    {
        "anchor": "Supersymmetry on the lattice: We discuss the motivations, difficulties and progress in the study of\nsupersymmetric lattice gauge theories focusing in particular on ${\\cal N}=1$\nand ${\\cal N}=4$ super Yang-Mills in four dimensions. Brief reviews of the\ncorresponding lattice formalisms are given and current results are presented\nand discussed. We conclude with a summary of the main aspects of current work\nand prospects for the future.",
        "positive": "The residual mass in Lattice Heavy Quark Effective Theory to alpha^3\n  order: We determine to order alpha^3 in the quenched approximation the so-called\nresidual mass in the lattice regularisation of the Heavy Quark Effective\nTheory. We follow a gauge-invariant strategy which exploits the fact that this\nmass term dominates the exponential decrease of perturbative Wilson loops at\nlarge perimeters. Our computational tool is Numerical Stochastic Perturbation\nTheory. The new coefficient we compute is crucial to improve the determination\nof the (MS bar) mass of the b-quark from lattice simulations of the Heavy Quark\nEffective Theory."
    },
    {
        "anchor": "Step scaling with gradient flow and finite temperature: We combine gradient flow, step-scaling, and finite-temperature boundary\nconditions to scale-set 2+1+1 flavor QCD lattices with physical HISQ quarks at\nmultiple spacings down to a=0.01378 fm, such that they represent the same\ntemperature at the percent level and the same quark mass to a few percent. This\npreparatory work will allow the evaluation and continuum extrapolation of the\ntopological susceptibility at up to 1 GeV temperatures with good control over\nquark-mass effects.",
        "positive": "Indications for infrared conformal behaviour of SU(2) gauge theory with\n  $N_f = 3/2$ flavours of adjoint fermions: {We present the results of a numerical investigation of SU(2) gauge theory\nwith $N_f=3/2$ flavours of fermions, corresponding to 3 Majorana fermions,\nwhich transform in the adjoint representation of the gauge group. At two values\nof the gauge coupling, the masses of bound states are considered as a function\nof the PCAC quark mass. The scaling of bound states masses indicates an\ninfrared conformal behaviour of the theory. We obtain estimates for the\nfixed-point value of the mass anomalous dimension $\\gamma^*$ from the scaling\nof masses and from the scaling of the mode number of the Wilson-Dirac operator."
    },
    {
        "anchor": "Residual Chiral Symmetry Breaking in Domain-Wall Fermions: We study the effective quark mass induced by the finite separation of the\ndomain walls in the domain-wall formulation of chiral fermion as the function\nof the size of the fifth dimension ($L_s$), the gauge coupling $\\beta$ and the\nphysical volume $V$. We measure the mass by calculating the small eigenvalues\nof the hermitian domain-wall Dirac operator ($H_{\\rm DWF}(m_0))$ in the\ntopologically-nontrivial quenched SU(3) gauge configurations. We find that the\ninduced quark mass is nearly independent of the physical volume, decays\nexponentially as a function of $L_s$, and has a strong dependence on the size\nof quantum fluctuations controlled by $\\beta$. The effect of the choice of the\nlattice gluon action is also studied.",
        "positive": "Chiral symmetry constraints on resonant amplitudes: We discuss the impact of chiral symmetry constraints on the quark-mass\ndependence of meson resonance pole positions, which are encoded in\nnon-perturbative parametrizations of meson scattering amplitudes.\nModel-independent conditions on such parametrizations are derived, which are\nshown to guarantee the correct functional form of the leading quark-mass\ncorrections to the resonance pole positions. Some model amplitudes for $\\pi\\pi$\nscattering, widely used for the determination of $\\rho$ and $\\sigma$ resonance\nproperties from results of lattice simulations, are tested explicitly with\nrespect to these conditions."
    },
    {
        "anchor": "Topological terms with qubit regularization and relativistic quantum\n  circuits: Qubit regularization provides a rich framework to explore quantum field\ntheories. The freedom to choose how the important symmetries of the theory are\nembedded in the qubit regularization scheme allows us to construct new lattice\nmodels with rich phase diagrams. Some of the phases can contain topological\nterms which lead to critical phases. In this work we introduce and study the\nSU(3)-F qubit regularization scheme to embed the SO(3) spin-symmetry. We argue\nthat qubit models in this regularization scheme contain several phases\nincluding a critical phase which describes the k = 1 Wess-Zumino-Witten (WZW)\nconformal field theory (CFT) at long distances, and two massive phases one of\nwhich is trvially gapped and the other which breaks the lattice translation\nsymmetry. We construct a simple space-time Euclidean lattice model with a\nsingle coupling U and study it using the Monte Carlo method. We show the model\nhas a critical phase at small U and a trivially massive phase at large U with a\nfirst order transition separating the two. Another feature of our model is that\nit is symmetric under space-time rotations, which means the temporal and\nspatial lattice spacing are connected to each other. The unitary time evolution\noperator obtained by a Wick rotation of the transfer matrix of our model can\nhelp us compute the physics of the k = 1 WZW CFT in real time without the need\nfor tuning the temporal lattice spacing to zero. We use this idea to introduce\nthe concept of a relativistic quantum circuit on a discrete space-time lattice.",
        "positive": "Taste symmetry breaking at finite temperature: The breaking of the taste symmetry is studied in the temperature range\nbetween 140 MeV to 550 MeV. In order to investigate this violation we have\ncalculated the screening masses of the various taste states fitting the\nexponential decay of the spatial correlators. The computation has been\nperformed using dynamical Nf = 2+1 gauge field configurations generated with\nthe p4 staggered action along the Line of Constant Physics (LCP) defined by a\npion mass $m_\\pi$ of approximately 220 MeV and the kaon mass $m_K$ equals 500\nMeV. For temperatures below the transition an agreement with the predictions of\nthe staggered chiral perturbation theory has been found and no temperature\neffect can be observed on the taste violation. Above the transition the taste\nsplitting still shows an O(a^2) behavior but with a temperature dependent\nslope. In addition to the analysis done for the pion multiplet we have\nperformed an analogous computation for the light-strange and strange mesons and\nalso looked at the scalar, vector and axial vector channels to understand how\nthe multiplets split at finite temperature. Finally the temperature dependence\nof the pion decay constant $f_{\\pi}$ is investigated to get further information\nabout the chiral symmetry restoration."
    },
    {
        "anchor": "Numerical study of staggered fermion on anisotropic lattices: We study calibration procedures of the staggered quarks on anisotropic\nlattices in the quenched approximation and in $N_f = 2$ dynamical simulations.\nFor the calibration conditions we adopt the hadronic radii $r_0$ and the meson\nmasses in the temporal and spatial directions. On the quenched lattice, we\ncalibrate the quark field and compare the result with the result determined\nusing the meson dispersion relation. In dynamical simulations, we determine the\nanisotropy parameters $\\gamma_G$ and $\\gamma_F$ simultaneously within 1%\naccuracy at renormalized anisotropy $\\xi = a_s/a_t = 4$.",
        "positive": "A nonperturbative determination of the O(a) improvement coefficient c_A\n  and the scaling of f_pi and m^{MSbar}: We report on an investigation of the LANL method for determining the O(a)\nimprovement coefficient c_A nonperturbatively. We find we are able to extract\nreliable estimates for the coefficient using this method. However, our study of\nsystematic errors shows that for very accurate determinations of c_A, the\nsmearing function must be tuned and the volume fixed to keep the O(a) ambiguity\nin c_A fixed as beta varies. Consistency was found with previous results from\nthe LANL group and (within fairly large errors) 1-loop perturbation theory; c_A\ndoes not change significantly over the range beta=5.93-6.2. The big difference\nbetween our results and those of the ALPHA collaboration, around beta=6.0, show\nthat the O(a) differences in c_A between the different methods can be large. We\nfind that the lattice spacing dependence of f_pi and the renormalised quark\nmass is much smaller using our values of the coefficient compared to those of\nthe ALPHA collaboration."
    },
    {
        "anchor": "Lattice QCD form factor for $B_s\\to D_s^* l\u03bd$ at zero recoil with\n  non-perturbative current renormalisation: We present details of a lattice QCD calculation of the $B_s\\to D_s^*$ axial\nform factor at zero recoil using the Highly Improved Staggered Quark (HISQ)\nformalism on the second generation MILC gluon ensembles that include up, down,\nstrange and charm quarks in the sea. Using the HISQ action for all valence\nquarks means that the lattice axial vector current that couples to the $W$ can\nbe renormalized fully non-perturbatively, giving a result free of the\nperturbative matching errors that previous lattice QCD calculations have had.\nWe calculate correlation functions at three values of the lattice spacing, and\nmultiple `$b$'-quark masses, for physical $c$ and $s$. The functional\ndependence on the $b$-quark mass can be determined and compared to Heavy Quark\nEffective Theory expectations, and a result for the form factor obtained at the\nphysical value of the $b$-quark mass. We find $\\mathcal{F}^{B_s\\to D_s^*}(1) =\nh^s_{A_1}(1) = 0.9020(96)_{\\text{stat}}(90)_{\\text{sys}}$. This is in agreement\nwith earlier lattice QCD results, which use NRQCD $b$ quarks, with a total\nuncertainty reduced by more than a factor of two. We discuss implications of\nthis result for the $B\\to D^*$ axial form factor at zero recoil and for\ndeterminations of $V_{cb}$.",
        "positive": "Comparison of perturbative RG theory with lattice data for the 4d Ising\n  model: Predictions for (phi^4)_4 theory from renormalization-group-improved\nperturbation theory, as formulated by Luescher and Weisz, are compared to\npublished (and some unpublished) data from lattice Monte-Carlo simulations of\nthe 4-dimensional Ising model. Good agreement is found in all but one\nrespect:-- the change in the wavefunction-renormalization constant Z_R across\nthe phase transition is significantly greater than predicted. A related\nobservation is that propagator data in the broken phase show deviations from\nfree-propagator form -- deviations that become larger, not smaller, closer to\nthe continuum limit. More data closer to the critical point are needed to\nclarify the situation."
    },
    {
        "anchor": "Nucleon charges and quark momentum fraction with $N_f=2+1$ Wilson\n  fermions: We present a nucleon structure analysis including local isovector charges as\nwell as twist-2 operator insertions. Computations are performed on CLS\nensembles with $N_f=2+1$ Wilson fermions, covering four values of the lattice\nspacing and pion masses down to $M_\\pi \\approx 200\\,\\mathrm{MeV}$. Several\nsource-sink separations (typically $\\sim 1.0\\,\\mathrm{fm}$ to $\\sim\n1.5\\,\\mathrm{fm}$) allow us to assess excited-state contaminations. Results on\neach ensemble are obtained from simultaneous two-state fits including all\nobservables and all available source-sink separations with the mass gap as a\nfree fit parameter. Finally, the chiral, continuum and finite size\nextrapolation is performed to extract physical results.",
        "positive": "Exploratory spectrum calculations using overlap valence quarks on a\n  staggered sea: We present exploratory results for the hadron mass spectrum and pseudoscalar\nmeson decay constants using mixed actions. We use improved staggered sea quarks\nand HYP-smeared overlap valence quarks. We obtain good signals on 10\nconfigurations at one lattice spacing and two different sets of sea quark\nmasses."
    },
    {
        "anchor": "Normalized entropy density of the 3D 3-state Potts model: Using a multicanonical Metropolis algorithm we have performed Monte Carlo\nsimulations of the 3D 3-state Potts model on $L^3$ lattices with L=20, 30, 40,\n50. Covering a range of inverse temperatures from $\\beta_{\\min}=0$ to\n$\\beta_{\\max}=0.33$ we calculated the infinite volume limit of the entropy\ndensity $s(\\beta)$ with its normalization obtained from $s(0)=\\ln 3$. At the\ntransition temperature the entropy and energy endpoints in the ordered and\ndisordered phase are estimated employing a novel reweighting procedure. We also\nevaluate the transition temperature and the order-disorder interface tension.\nThe latter estimate increases when capillary waves are taken into account.",
        "positive": "Omega_bbb excited-state spectroscopy from lattice QCD: Triply heavy baryons are very interesting systems analogous to heavy\nquarkonia, but are difficult to access experimentally. Lattice QCD can provide\nprecise predictions for these systems, which can be compared to other\ntheoretical approaches. In this work, the spectrum of excited states of the\nOmega_bbb baryon is calculated using lattice NRQCD for the b quarks, and using\na domain-wall action for the u, d and s sea quarks. The calculations are done\nfor multiple values of the sea-quark masses, and for two different lattice\nspacings. The energies of states with angular momentum up to J=7/2 are\ncalculated, and the effects of rotational symmetry breaking by the lattice are\nanalyzed. Precise results are obtained even for the small spin-dependent energy\nsplittings, and the contributions of individual NRQCD interactions to these\nenergy splittings are studied. The results are compared to potential-model\ncalculations."
    },
    {
        "anchor": "Bridge++ 2.0: Benchmark results on supercomputer Fugaku: Bridge++ is a general-purpose code set for lattice QCD simulations aiming at\na readable, extensible, and portable code while keeping practical high\nperformance. The new version 2.0 employs machine-dependent optimization,\nenabling flexible data layout in float/double precision, while it was fixed\nlayout and only with the double precision in previous versions. We report the\nperformance on supercomputer Fugaku with Arm A64FX-SVE architecture by Fujitsu.",
        "positive": "Streamlined data analysis in Python: Python is a particularly appealing language to carry out data analysis, owing\nin part to its user-friendly character as well as its access to well maintained\nand powerful libraries like NumPy and SciPy. Still, for the purpose of\nanalyzing data in a lattice QCD context, some desirable functionality is\nmissing from these libraries. Moreover, scripting languages tend to be slower\nthan compiled ones. To help address these points we present the\nAnalysisToolbox, a collection of Python modules to facilitate lattice QCD data\nanalysis. Some highlighted features include general-purpose jackknife and\nbootstrap routines; modules for reading in and storing gauge configurations; a\nmodule to carry out hadron resonance gas model calculations; and convenience\nwrappers for SciPy integration, curve fitting, and splines. These features are\nsped up behind the scenes using parallelization and just-in-time compilation."
    },
    {
        "anchor": "Scaling in the Positive Plaquette Model and Universality in SU(2)\n  Lattice Gauge Theory: We investigate universality, scaling, the beta-function and the topological\ncharge in the positive plaquette model for SU(2) lattice gauge theory.\nComparing physical quantities, like the critical temperature, the string\ntension, glueball masses, and their ratios, we explore the effect of a complete\nsuppression of a certain lattice artifact, namely the negative plaquettes, for\nSU(2) lattice gauge theory. Our result is that this modification does not\nchange the continuum limit, i.e., the universality class. The positive\nplaquette model and the standard Wilson formulation describe the same physical\nsituation. The approach to the continuum limit given by the beta-function in\nterms of the bare lattice coupling, however, is rather different: the\nbeta-function of the positive plaquette model does not show a dip like the\nmodel with standard Wilson action.",
        "positive": "Lattice gauge theory and gluon color-confinement in curved spacetime: The lattice gauge theory for curved spacetime is formulated. A discretized\naction is derived for both gluon and quark fields which reduces to the\ngenerally covariant form in the continuum limit. Using the Wilson action, it is\nshown analytically that for a general curved spacetime background, two\npropagating gluons are always color-confined. The fermion-doubling problem is\ndiscussed in the specific case of Friedman-Robertson-Walker metric. Lastly, we\ndiscussed possible future numerical implementation of lattice QCD in curved\nspacetime."
    },
    {
        "anchor": "A new phase in the Lorentzian type IIB matrix model and the emergence of\n  continuous space-time: The Lorentzian type IIB matrix model is a promising candidate for a\nnon-perturbative formulation of superstring theory. In previous studies, Monte\nCarlo calculations provided interesting results indicating the spontaneous\nbreaking of SO(9) to SO(3) and the emergence of (3+1)-dimensional space-time.\nHowever, an approximation was used to avoid the sign problem, which seemed to\nmake the space-time structure singular. In this talk, we report our results\nobtained by using the complex Langevin method to overcome the sign problem\ninstead of using this approximation. In particular, we discuss the emergence of\ncontinuous space-time in a new phase, which we discovered recently.",
        "positive": "Hadron masses in QCD with one quark flavour: One-flavour QCD - a gauge theory with SU(3) colour gauge group and a fermion\nin the fundamental representation - is studied by Monte Carlo simulations. The\nmass spectrum of hadronic bound states is investigated in a volume with\nextensions of L ~ 4.4r_0 (~2.2fm) at two different lattice spacings: a ~\n0.37r_0 (~0.19fm) and a ~ 0.27r_0 (~0.13fm). The lattice action is Symanzik\ntree-level-improved Wilson action for the gauge field and (unimproved) Wilson\naction for the fermion."
    },
    {
        "anchor": "Lattice pure gauge compact QED in the Landau gauge: the photon\n  propagator, the phase structure and the presence of Dirac strings: In this work we investigate the lattice Landau gauge photon propagator\ntogether with the average number of Dirac strings in the compact formulation of\nQED for the pure gauge version of the theory as a function of the coupling\nconstant. Their $\\beta$ dependence show that these two quantities can be used\nto identify the confinement-deconfinement transition and that the nature of\nthis transition is first order. Our results show that in the confined phase the\npropagator is always finite, the theory has a mass gap and the number of Dirac\nstrings present in the configuration is two orders of magnitude larger than in\nthe deconfined phase. Furthermore, in the deconfined phase where $ \\beta \\ge\n1.0125$ the theory becomes massless, there are essentially no Dirac strings and\nthe photon propagator diverges when the limit $p \\rightarrow 0^+$ is taken. Our\nresults illustrate the importance of the topological structures in the dynamics\nof the two phases.",
        "positive": "Ginsparg-Wilson relation and the overlap formula: The fermionic determinant of a lattice Dirac operator that obeys the\nGinsparg-Wilson relation factorizes into two factors that are complex conjugate\nof each other. Each factor is naturally associated with a single chiral fermion\nand can be realized as a overlap of two many body vacua."
    },
    {
        "anchor": "The perfect action for non-degenerate staggered fermions: The perfect action of free staggered fermions is calculated by blocking from\nthe continuum for degenerate and non-degenerate flavor masses. The symmetry\nstructure, connecting flavor transformations and translations, is explained\ndirectly from the blocking scheme. It is convenient to use a modified Fourier\ntransformation, respecting this connection, to treat the spin-flavor structure\nof the blockspins. The perfect action remains local in the non-degenerate case;\nit is explicitly calculated in two dimensions. I finally comment on the\nrelation of the blocking scheme to the transition from Dirac-K\\\"ahler fermions\nto staggered fermions.",
        "positive": "Topological aspects of G2 Yang-Mills theory: Yang-Mills theory and QCD are well-defined for any Lie group as gauge group.\nThe choice G2 is of great interest, as it is the smallest group with trivial\ncenter and being at the same time accessible to simulations. This theory has\nbeen found to have many properties in common with SU(3) Yang-Mills theory and\nQCD, permitting to study the role of the center. Herein, these investigations\nare extended to topological properties of G2 Yang-Mills theory. After giving\nthe instanton construction for G2, topological lumps with instanton topological\ncharge are identified in cooled lattice configurations. The corresponding\ntopological susceptibility is determined in the vacuum and at low and high\ntemperatures, showing a significant response to the phase structure of the\ntheory."
    },
    {
        "anchor": "Review of lattice results concerning low energy particle physics: We review lattice results related to pion, kaon, D- and B-meson physics with\nthe aim of making them easily accessible to the particle physics community.\nMore specifically, we report on the determination of the light-quark masses,\nthe form factor f+(0), arising in semileptonic K -> pi transition at zero\nmomentum transfer, as well as the decay constant ratio fK/fpi of decay\nconstants and its consequences for the CKM matrix elements Vus and Vud.\nFurthermore, we describe the results obtained on the lattice for some of the\nlow-energy constants of SU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation\nTheory and review the determination of the BK parameter of neutral kaon mixing.\nThe inclusion of heavy-quark quantities significantly expands the FLAG scope\nwith respect to the previous review. Therefore, for this review, we focus on D-\nand B-meson decay constants, form factors, and mixing parameters, since these\nare most relevant for the determination of CKM matrix elements and the global\nCKM unitarity-triangle fit. In addition we review the status of lattice\ndeterminations of the strong coupling constant alpha_s.",
        "positive": "Phase structure of the Higgs-Yukawa systems with chirally invariant\n  lattice fermion actions: We develop analytical technique for examining phase structure of $Z_2$,\n$U(1)$, and $SU(2)$ lattice Higgs-Yukawa systems with radially frozen Higgs\nfields and chirally invariant lattice fermion actions. The method is based on\nvariational mean field approximation. We analyse phase diagrams of such systems\nwith different forms of lattice fermion actions and demonstrate that it\ncrucially depends both on the symmetry group and on the form of the action. We\ndiscuss location in the diagrams of possible non-trivial fixed points relevant\nto continuum physics, and argue that the candidates can exist only in $Z_2$\nsystem with SLAC action and $U(1)$ systems with naive and SLAC actions. [Note:\nBy a product, missing term in Eq. (3.5) of hep-lat/9309010 is reconstructed,\nthat, however, affects only the result of Sect. 4.3 (Fig. 3) of that reference\n(cf. Fig. 2(c) of this paper).]"
    },
    {
        "anchor": "On the Extraction of the Strong Coupling from Hadronic Tau Decay: The finite energy sum rule extraction of the strong coupling {\\alpha}_s from\nhadronic {\\tau} decay data provides one of its most precise experimental\ndeterminations. As precision improves, small non-perturbative effects become\nincreasingly relevant to both the central value and error. Here we present a\nnew framework for this extraction employing a physically motivated model to\naccommodate violations of quark-hadron duality and enforcing a consistent\ntreatment of higher-dimension operator product expansion contributions. Using\n1998 OPAL data for the non-strange vector and axial-vector spectral functions,\nwe find the n_f=3 values for {\\alpha}_s(m_{\\tau}^2) of 0.307(19) for\nfixed-order perturbation theory and 0.322(26) for contour-improved perturbation\ntheory, corresponding to n_f=5 values for {\\alpha}_s(M_Z^2) of 0.1169(25) and\n0.1187(32), respectively.",
        "positive": "Numerical study of Frohlich and Marchetti monopole creation operator: The monopole creation operator proposed recently by Frohlich and Marchetti is\ninvestigated in the Abelian Higgs model with compact gauge field. We show\nnumerically that the creation operator detects the condensation of monopoles in\nthe presence of the dynamical matter field."
    },
    {
        "anchor": "Strange quark momentum fraction from overlap fermion: We present a calculation of $< x >_s$ for the strange quark in the nucleon.\nWe also report the ratio of the strange $< x >$ to that of $u/d$ in the\ndisconnected insertion which will be useful in constraining the global fit of\nparton distribution functions at small $x$. We adopt overlap fermion action on\n$2 + 1$ flavor domain-wall fermion configurations on the $24^3 \\times 64$\nlattice with a light sea quark mass which corresponds to $m_{\\pi}=330$ MeV.\nSmeared grid $Z_3$ sources are deployed to calculate the nucleon propagator\nwith low-mode substitution. Even-odd grid sources and time-dilution technique\nwith stochastic noises are used to calculate the high mode contribution to the\nquark loop. Low mode averaging (LMA) for the quark loop is applied to reduce\nthe statistical error of the disconnected insertion calculation. We find the\nratio $< x >_s/< x >_{u/d}^{\\mathrm{DI}}= 0.78(3)$ in this study.",
        "positive": "Determination of Anisotropy Coefficients for SU(3) Gauge Actions from\n  the Integral and Matching Methods: We use two non-perturbative methods to obtain the anisotropy derivatives of\nthe coupling constants (the anisotropy coefficients) of SU(3) lattice gauge\ntheory. These coefficients appear in the derivative formulae for the energy\ndensity and the pressure. We calculate them for the standard Wilson and two\nimproved actions, the 2x2 and the Square Symanzik action. Both methods lead for\nall investigated actions to compatible results which are clearly different from\ntheir known asymptotic perturbative limits. With increasing beta the limits are\nhowever approached in all cases. Our findings strongly support the equivalence\nof the integral and derivative methods for the calculation of energy density\nand pressure."
    },
    {
        "anchor": "Exact Solution of Induced Lattice Gauge Theory at Large $N$: We find the exact solution of a recently proposed model of the lattice gauge\ntheory induced by heavy scalar field in adjoint representation at $ N= \\infty $\nfor arbitrary dimension $D$. The nonlinear integral equation for the gauge\ninvariant density of eigenvalues of the vacuum average of the scalar field is\nderived. In the continuum limit, the density grows as $ \\phi^{\\alpha} $ where $\n\\alpha = 1 + \\frac{1}{\\pi}\\arccos\\frac{D}{3D-2} $.",
        "positive": "The chiral and angular momentum content of the rho-meson: It is possible to define and calculate in a gauge-invariant manner the chiral\nas well as the partial wave content of the quark-antiquark Fock component of a\nmeson in the infrared, where mass is generated. Using the variational method\nand a set of interpolators that span a complete chiral basis we extract in a\nlattice QCD Monte Carlo simulation with two dynamical light quarks the orbital\nangular momentum and spin content of the rho-meson. We obtain in the infrared a\nsimple 3S1 component as a leading component of the rho-meson with a small\nadmixture of the 3D1 partial wave, in agreement with the SU(6) flavor-spin\nsymmetry."
    },
    {
        "anchor": "SU(2) Lattice Gauge Theory Simulations on Fermi GPUs: In this work we explore the performance of CUDA in quenched lattice SU(2)\nsimulations. CUDA, NVIDIA Compute Unified Device Architecture, is a hardware\nand software architecture developed by NVIDIA for computing on the GPU. We\npresent an analysis and performance comparison between the GPU and CPU in\nsingle and double precision. Analyses with multiple GPUs and two different\narchitectures (G200 and Fermi architectures) are also presented. In order to\nobtain a high performance, the code must be optimized for the GPU architecture,\ni.e., an implementation that exploits the memory hierarchy of the CUDA\nprogramming model.\n  We produce codes for the Monte Carlo generation of SU(2) lattice gauge\nconfigurations, for the mean plaquette, for the Polyakov Loop at finite T and\nfor the Wilson loop. We also present results for the potential using many\nconfigurations ($50\\ 000$) without smearing and almost $2\\ 000$ configurations\nwith APE smearing. With two Fermi GPUs we have achieved an excellent\nperformance of $200 \\times$ the speed over one CPU, in single precision, around\n110 Gflops/s. We also find that, using the Fermi architecture, double precision\ncomputations for the static quark-antiquark potential are not much slower (less\nthan $2 \\times$ slower) than single precision computations.",
        "positive": "Finite temperature phase transition in lattice QCD with N_f=2\n  nonperturbatively improved Wilson fermions at N_t=8: The finite temperature lattice QCD with N_f=2 nonperturbatively improved\nWilson fermions is studied on 16^3 8 lattice. Using abelian projection after\nfixing to MA gauge we determine the transition temperature for m_{\\pi}/m_{\\rho}\n\\sim 0.8."
    },
    {
        "anchor": "Towards the QCD phase diagram: We summarize our recent results on the phase diagram of QCD with N_f=2+1\nquark flavors, as a function of temperature T and quark chemical potential \\mu.\nUsing staggered fermions, lattices with temporal extent N_t=4, and the exact\nRHMC algorithm, we first determine the critical line in the quark mass plane\n(m_{u,d},m_s) where the finite temperature transition at \\mu=0 is second order.\nWe confirm that the physical point lies on the crossover side of this line. Our\ndata are consistent with a tricritical point at (m_{u,d},m_s) = (0,\\sim 500)\nMeV.\n  Then, using an imaginary chemical potential, we determine in which direction\nthis second-order line moves as the chemical potential is turned on. Contrary\nto standard expectations, we find that the region of first-order transitions\nshrinks in the presence of a chemical potential, which is inconsistent with the\npresence of a QCD critical point at small chemical potential.\n  The emphasis is put on clarifying the translation of our results from lattice\nto physical units, and on discussing the apparent contradiction of our findings\nwith earlier lattice studies.",
        "positive": "Finite size scaling of the balls in boxes model: We discuss the finite size behaviour in the canonical ensemble of the balls\nin boxes model. We compare theoretical predictions and numerical results for\nthe finite size scaling of cumulants of the energy distribution in the\ncanonical ensemble and perform a detailed analysis of the first and third order\nphase transitions which appear for different parameter values in the model."
    },
    {
        "anchor": "Fermionic fields in the pseudoparticle approach: The pseudoparticle approach is a numerical method to compute path integrals\nwithout discretizing spacetime. The basic idea is to consider only those field\nconfigurations, which can be represented as a linear superposition of a small\nnumber of localized building blocks (pseudoparticles), and to replace the\nfunctional integration by an integration over the pseudoparticle degrees of\nfreedom. In previous papers we have successfully applied the pseudoparticle\napproach to SU(2) Yang-Mills theory. In this work we discuss the inclusion of\nfermionic fields in the pseudoparticle approach. To test our method, we compute\nthe phase diagram of the 1+1-dimensional Gross-Neveu model in the large-N limit\nas well as the chiral condensate in the crystal phase.",
        "positive": "Charmonium spectrum from quenched QCD on anisotropic lattices: We present our final results of the charmonium spectrum in quenched QCD on\nanisotropic lattices. Simulations are made with the plaquette gauge action and\na tadpole improved clover quark action employing $\\xi = a_s/a_t = 3$. We\ncalculate the spectrum of S- and P-states and their excitation, and study the\nscaling behavior of mass splittings. Comparison is made with the experiment and\nprevious lattice results. The issue of hyperfine splitting for different\nchoices of the clover coefficients obtained by Klassen is discussed."
    },
    {
        "anchor": "Color screening potential at finite density in two-flavor lattice QCD\n  with Wilson fermions: We investigate chemical-potential (\\mu) dependence of static-quark free\nenergies in both the real and imaginary \\mu regions, performing lattice QCD\nsimulations at imaginary \\mu and extrapolating the results to the real \\mu\nregion with analytic continuation. Lattice QCD calculations are done on a\n16^{3}\\times 4 lattice with the clover-improved two-flavor Wilson fermion\naction and the renormalization-group improved Iwasaki gauge action.\nStatic-quark potential is evaluated from the Polyakov-loop correlation\nfunctions in the deconfinement phase. As the analytic continuation, the\npotential calculated at imaginary \\mu=i\\mu_{\\rm I} is expanded into a\nTaylor-expansion series of i\\mu_{\\rm I}/T up to 4th order and the pure\nimaginary variable i\\mu_{\\rm I}/T is replaced by the real one \\mu_{\\rm R}/T. At\nreal \\mu, the 4th-order term weakens \\mu dependence of the potential sizably.\nAt long distance, all of the color singlet and non-singlet potentials tend to\ntwice the single-quark free energy, indicating that the interactions between\nheavy quarks are fully color-screened for finite \\mu. For both real and\nimaginary \\mu, the color-singlet q{\\bar q} and the color-antitriplet qq\ninteraction are attractive, whereas the color-octet q{\\bar q} and the\ncolor-sextet qq interaction are repulsive. The attractive interactions have\nstronger \\mu/T dependence than the repulsive interactions. The color-Debye\nscreening mass is extracted from the color-singlet potential at imaginary \\mu,\nand the mass is extrapolated to real \\mu by analytic continuation. The\nscreening mass thus obtained has stronger \\mu dependence than the prediction of\nthe leading-order thermal perturbation theory at both real and imaginary \\mu.",
        "positive": "Chiral Symmetry Breaking on the Lattice: a Study of the Strongly Coupled\n  Lattice Schwinger Model: We revisit the strong coupling limit of the Schwinger model on the lattice\nusing staggered fermions and the hamiltonian approach to lattice gauge\ntheories. Although staggered fermions have no continuous chiral symmetry, they\nposses a discrete axial invari ance which forbids fermion mass and which must\nbe broken in order for the lattice Schwinger model to exhibit the features of\nthe spectrum of the continuum theory. We show that this discrete symmetry is\nindeed broken spontaneously in the strong coupling li mit. Expanding around a\ngauge invariant ground state and carefully considering the normal ordering of\nthe charge operator, we derive an improved strong coupling expansion and\ncompute the masses of the low lying bosonic excitations as well as the chiral\nco ndensate of the model. We find very good agreement between our lattice\ncalculations and known continuum values for these quantities already in the\nfourth order of strong coupling perturbation theory. We also find the exact\nground state of the antiferromag netic Ising spin chain with long range Coulomb\ninteraction, which determines the nature of the ground state in the strong\ncoupling limit."
    },
    {
        "anchor": "The parity partner of the nucleon in quenched QCD with domain wall\n  fermions: We present preliminary results for the mass spectrum of the nucleon and its\nlow-lying excited states from quenched lattice QCD using the domain wall\nfermion method which preserves the chiral symmetry at finite lattice cutoff.\nDefinite mass splitting is observed between the nucleon and its parity partner.\nThis splitting grows with decreasing valence quark mass. We also present\npreliminary data regarding the first positive-parity excited state.",
        "positive": "B and D meson decay constants from 2+1 flavor improved staggered\n  simulations: We give an update on simulation results for the decay constants f_B, f_{B_s},\nf_D and f_{D_s}. These decay constants are important for precision tests of the\nstandard model, in particular entering as inputs to the global CKM unitarity\ntriangle fit. The results presented here make use of the MILC (2+1)-flavor\nasqtad ensembles, with heavy quarks incorporated using the clover action with\nthe Fermilab method. Partially quenched, staggered chiral perturbation theory\nis used to extract the decay constants at the physical point. In addition, we\ngive error projections for a new analysis in progress, based on an extended\ndata set."
    },
    {
        "anchor": "Correlation Functions of Hadron Currents in the QCD Vacuum Calculated in\n  Lattice QCD: Point-to-point vacuum correlation functions for spatially separated hadron\ncurrents are calculated in quenched lattice QCD on a $16^3\\times 24$ lattice\nwith $6/g^2=5.7$. The lattice data are analyzed in terms of dispersion\nrelations, which enable us to extract physical information from small distances\nwhere asymptotic freedom is apparent to large distances where the hadronic\nresonances dominate. In the pseudoscalar, vector, and axial vector channels\nwhere experimental data or phenomenological information are available,\nsemi-quantitative agreement is obtained. In the nucleon and delta channels,\nwhere no experimental data exist, our lattice data complement experiments.\nComparison with approximations based on sum rules and interacting instantons\nare made, and technical details of the lattice calculation are described.",
        "positive": "Universal Distribution of Would-be Topological Zero Modes in Coupled\n  Chiral Systems: We consider two quenched, chiral ensembles which are coupled in such a way\nthat a combined chiral symmetry is preserved. The coupling also links the\ntopology of the two systems such that the number of exact zero modes in the\ncoupled system equals the sum of the number of zero modes in the two uncoupled\nsystems counted with sign. The canceled modes that turn non-topological due to\nthe coupling become near-zero modes at small coupling. We analyze the\ndistribution of these would-be zero modes using effective field theory. The\ndistribution is universal and, in the limit of small coupling, the would-be\nzero modes are distributed according to a finite size chiral Gaussian ensemble,\nwhere the width of the distribution scales as the inverse square root of the\nvolume."
    },
    {
        "anchor": "Isospin Breaking Effects in the 2-Flavor Schwinger Model: The automatic fine-tuning of isospin breaking effects by conformal\ncoalescence found by Georgi in the 2-flavor Schwinger model is studied. The\nanalytical results obtained for the bosonic correlators are elaborated and the\nmass splitting parameter in leading order determined. Numerical investigation\nof meson mass splitting confirms the exponential suppression of symmetry\nbreaking effects even for mass differences $\\delta m$ near the fermion mass\n$m_f$.",
        "positive": "Numerical simulation of QCD with u, d, s and c quarks in the\n  twisted-mass Wilson formulation: A first study of numerical Monte Carlo simulations with two quark doublets, a\nmass-degenerate one and a mass-split one, interpreted as u, d, s and c quarks,\nis carried out in the framework of the twisted mass Wilson lattice formulation.\nTuning the bare parameters of this theory is explored on 12^3x24 and 16^3x32\nlattices at lattice spacings a=0.20fm and a=0.15fm, respectively."
    },
    {
        "anchor": "Non-perturbatively Renormalized Light Quark Masses with Two Dynamical\n  Fermions: We present the results of a partially quenched lattice QCD calculation of\nlight quark masses with $N_f=2$ degenerate dynamical flavors. Numerical\nsimulations are carried out using the plaquette gauge action and the Wilson\nquark action at $\\beta = 5.8$ ($a^{-1} \\simeq 3.2\\gev$). The spatial extension\nof the $24^3 \\times 48$ lattice is about 1.5 fm. Configurations have been\ngenerated at four values of the sea quark masses, for which the ratio of\npseudoscalar over vector meson masses is in the range $M_P/M_V \\simeq 0.60 \\div\n0.75$. An important feature of the present study is the use of non-perturbative\nrenormalization, performed with the $\\ri$ method. The effects of dynamical sea\nquarks in the determination of light quark masses have been investigated by\nperforming a quenched calculation on a similar lattice. Our results for the\naverage up-down and strange quark masses are $m_{ud}^{MS} (2\\gev) = 4.3(4)\n(^{+1.1}_{-0.4})\\mev$ and $m_s^{MS}(2\\gev)=101(8)(^{+25}_{-9}) \\mev$. These\nvalues are larger than those obtained by evaluating the quark mass\nrenormalization constants with one-loop (boosted) perturbation theory. Our\nresults for the light quark masses are compatible with those obtained in the\nquenched simulation. No significant sea quark effects are seen, at the values\nof sea quark masses used in the present study.",
        "positive": "B-meson physics from non-perturbative lattice heavy quark effective\n  theory: During the last years, the ALPHA collaboration has been developing and\nimplementing a method based on Heavy Quark Effective Theory (HQET) to compute\nB-mesons observables through lattice simulations. Thanks to a non-perturbative\nmatching to QCD, the theory is renormalizable at any order of the heavy quark\nmass expansion. In order to extract precisely the relevant matrix elements and\nmasses, we use all-to-all propagators and solve an generalized eigenvalue\nproblem (GEVP). We have shown in the quenched approximation that quantities\nlike the b-quark mass mb, the heavy-light decay constant(s) or the B-meson\nspectrum can be computed precisely beyond the static approximation (including\nthe first corrections in 1/\\mb). More recently, we have started to include the\nsea quark effects, by working with Nf=2 light flavors of dynamical fermions[1].\nThe computation of the matching parameters is almost finished, but concerning\nthe extraction of the hadronic quantities for which we use some CLS\nensembles[2], only one lattice spacing has been analyzed so far. In this\nproceeding we report on the status of this project and present some preliminary\nresults."
    },
    {
        "anchor": "A scaling study of the step scaling function in SU(3) gauge theory with\n  improved gauge actions: We study the scaling behavior of the step scaling function for SU(3) gauge\ntheory, employing the renormalization-group improved Iwasaki gauge action and\nthe perturbatively improved L\\\"uscher-Weisz gauge action. We confirm that the\nstep scaling functions from the improved gauge actions agree with that\npreviously obtained from the plaquette action within errors in the continuum\nlimit at both weak and strong coupling regions. We also investigate how\ndifferent choices of boundary counter terms for the improved gauge actions\naffect the scaling behavior. In the extrapolation to the continuum limit, we\nobserve that the cut off dependence becomes moderate for the Iwasaki action, if\na perturbative reduction of scaling violations is applied to the simulation\nresults. We also measure the low energy scale ratio with the Iwasaki action,\nand confirm its universality.",
        "positive": "Lattice QCD with strong external electric fields: We study particle generation by a strong electric field in lattice QCD. To\navoid the sign problem of the Minkowskian electric field, we adopt the\n\"isospin\" electric charge. When a strong electric field is applied, the\ninsulating vacuum is broken down and pairs of charged particles are produced by\nthe Schwinger mechanism. The competition against the color confining force is\nalso discussed."
    },
    {
        "anchor": "SU(3) Lattice Gauge Theory in the Fundamental--Adjoint Plane and Scaling\n  Along the Wilson Axis: We present further evidence for the bulk nature of the phase transition line\nin the fundamental--adjoint action plane of SU(3) lattice gauge theory.\nComputing the string tension and some glueball masses along the thermal phase\ntransition line of finite temperature systems with $N_t=4$, which was found to\njoin onto the bulk transition line at its endpoint, we find that the ratio\n$\\sqrt{\\sigma} / T_c$ remains approximately constant. However, the mass of the\n$0^{++}$ glueball decreases as the endpoint of the bulk transition line is\napproached, while the other glueball masses appear unchanged. This is\nconsistent with the notion that the bulk transition line ends in a critical\nendpoint, with the continuum limit there being a $\\phi^4$ theory with a\ndiverging correlation length only in the $0^{++}$ channel. We comment on the\nimplications for the scaling behavior along the fundamental or Wilson axis.",
        "positive": "Spin splittings among charmed hadrons: The mass differences between spin-1/2 and spin-3/2 baryons are compared to\nthe mass differences between spin-0 and spin-1 mesons. Results of simulations\nfor charmed hadrons in the quenched approximation from a tadpole-improved\nanisotropic action are discussed in the context of other lattice calculations,\nquark model predictions, heavy quark symmetry predictions and experimental\ndata."
    },
    {
        "anchor": "Two-point functions of quenched lattice QCD in Numerical Stochastic\n  Perturbation Theory. (I) The ghost propagator in Landau gauge: This is the first of a series of two papers on the perturbative computation\nof the ghost and gluon propagators in SU(3) Lattice Gauge Theory. Our final aim\nis to eventually compare with results from lattice simulations in order to\nenlight the genuinely non-perturbative content of the latter. By means of\nNumerical Stochastic Perturbation Theory we compute the ghost propagator in\nLandau gauge up to three loops. We present results in the infinite volume and\n$a \\to 0$ limits, based on a general strategy that we discuss in detail.",
        "positive": "Test for a universal behavior of Dirac eigenvalues in the complex\n  Langevin method: We apply the complex Langevin (CL) method to a chiral random matrix theory\n(ChRMT) at non-zero chemical potential and study the nearest neighbor spacing\n(NNS) distribution of the Dirac eigenvalues. The NNS distribution is extracted\nusing an unfolding procedure for the Dirac eigenvalues obtained in the CL\nmethod. For large quark mass, we find that the NNS distribution obeys the\nGinibre ensemble as expected. For small quark mass, the NNS distribution\nfollows the Wigner surmise for correct convergence case, while it follows the\nGinibre ensemble for wrong convergence case. The Wigner surmise is physically\nreasonable from the chemical potential independence of the ChRMT. The Ginibre\nensemble is known to be favored in a phase quenched QCD at finite chemical\npotential. Our result suggests a possibility that the originally universal\nbehavior of the NNS distribution is preserved even in the CL method for correct\nconvergence case."
    },
    {
        "anchor": "The N_t=4 finite temperature phase transition for lattice QCD with a\n  weak chiral 4-fermion interaction: We study the finite temperature phase transition of lattice QCD with an\nirrelevant chiral 4-fermion interaction and two massless quark flavours, on\n$8^3 \\times 4$ and $12^2 \\times 24 \\times 4$ lattices. The strength of the\n4-fermion interaction was reduced to half the minimum value used in previous\nsimulations, to study how the nature of this phase transition depends on this\nadditional interaction. We find that the transition remains first order as the\n4-fermion coupling is reduced. Extending our earlier studies indicates that for\nsufficiently large 4-fermion coupling, the transition is probably second order.",
        "positive": "Perturbative Removal of a Sign Problem: This paper presents a method for alleviating sign problems in lattice path\nintegrals, including those associated with finite fermion density in\nrelativistic systems. The method makes use of information gained from some\nsystematic expansion -- such as perturbation theory -- in order to accelerate\nthe Monte Carlo. The method is exact, in the sense that no approximation to the\nlattice path integral is introduced. Thanks to the underlying systematic\nexpansion, the method is systematically improvable, so that an arbitrary\nreduction in the sign problem can in principle be obtained. The Thirring model\n(in 0 + 1 and 1 + 1 dimensions) is used to demonstrate the ability of this\nmethod to reduce the finite-density sign problem."
    },
    {
        "anchor": "Testing Haldane's Conjecture in the O(3) Model by a Meron Cluster\n  Simulation: Twelve years ago, Haldane formulated his famous conjecture for 1-d\nantiferromagnetic quantum spin chains. In the context of the 2-d O(3) model\nwith a \\theta term, it predicts a phase transition at \\theta = \\pi, which has\nnot yet been verified reliably. To simulate this we use the Wolff cluster\nalgorithm together with an improved estimator for the topological charge\ndistribution. Each cluster carries integer or half integer charge. Clusters\nwith charge 1/2 are identified with merons. At \\theta = \\pi they are inactive,\nsuch that the mass gap vanishes. We obtain critical exponents which are\nconsistent with predictions from the k=1 WZNW model, therefore confirming a\nsecond order phase transition.",
        "positive": "CP, T and CPT in the non-perturbative formulation of chiral gauge\n  theories: In spite of significant recent progress on the non-perturbative formulation\nof chiral gauge theories there remained several unsolved problems. One of them\nis the puzzle that the left- and right-handed projectors, and so the left- and\nright-handed actions, break CP-symmetry on the lattice. We show in this letter\nthat they break T-symmetry also, while CPT remains intact."
    },
    {
        "anchor": "In search of a Hagedorn transition in SU(N) lattice gauge theories at\n  large-N: We investigate on the lattice the metastable confined phase above Tc in SU(N)\ngauge theories, for N=8,10, and 12. In particular we focus on the decrease with\nthe temperature of the mass of the lightest state that couples to Polyakov\nloops. We find that at T=Tc the corresponding effective string tension\n\\sigma_{eff}(T) is approximately half its value at T=0, and that as we increase\nT beyond Tc, while remaining in the confined phase, \\sigma_{eff}(T) continues\nto decrease. We extrapolate \\sigma_{eff}(T) to even higher temperatures, and\ninterpret the temperature where it vanishes as the Hagedorn temperature T_H.\nFor SU(12) we find that T_H/Tc=1.116(9), when we use the exponent of the\nthree-dimensional XY model for the extrapolation, which seems to be slightly\npreferred over a mean-field exponent by our data.",
        "positive": "Deconfinement in pure gauge SU(3) Yang-Mills theory: the ghost\n  propagator: The ghost propagator in Landau gauge is studied at finite temperature below\nand above $T_c$ using lattice QCD simulations. For high temperatures, we find\nthat the ghost propagator is enhanced, compared to the confined phase. The\nresults suggest that the ghost propagator can be used to identify the phase\ntransition, similarly to the gluon propagator case."
    },
    {
        "anchor": "Schwinger pair creation with the backreaction in 3 + 1 dimensions: In this work, I analyze the structure of the QED spacetime lattice and review\nthe Schwinger pair creation process from a thermodynamic point of view. This\nviewpoint enables the dynamical mean-field calculation for the 3 + 1\ndimensional Schwinger pair creation with the backreaction. As an example, I\ndemonstrate how to evaluate the pair creation in a finite volume with external\nelectric fields turned on at $t = 0$. The numerical results show how the\nbackreaction responds to the external fields and influences the pair creation.",
        "positive": "The Realization of the Sharpe-Singleton Scenario: The microscopic spectral density of the Wilson Dirac operator for two flavor\nlattice QCD is analyzed. The computation includes the leading order a^2\ncorrections of the chiral Lagrangian in the microscopic limit. The result is\nused to demonstrate how the Sharpe-Singleton first order scenario is realized\nin terms of the eigenvalues of the Wilson Dirac operator. We show that the\nSharpe-Singleton scenario only takes place in the theory with dynamical\nfermions whereas the Aoki phase can be realized in the quenched as well as the\nunquenched theory. Moreover, we give constraints imposed by gamma_5-Hermiticity\non the additional low energy constants of Wilson chiral perturbation theory."
    },
    {
        "anchor": "New simulation strategies for lattice gauge theory: Despite the numerous successful applications of lattice QCD in nuclear and\nparticle theory, fundamental algorithmic challenges remain. Among those,\nrelevant for numerical studies of QCD on a space-time torus, is topological\nfreezing--a form of critical slowing down, which becomes particularly acute for\nlattice spacings less than 0.05 fm. In these proceedings, I highlight several\nrecently proposed simulation strategies for ameliorating the problem of\ntopological freezing, and discuss both their advantages and disadvantages.\nThen, I turn focus toward potential strategies for addressing critical slowing\ndown in a more general context.",
        "positive": "Topological Structure of the QCD Vacuum Revealed by Overlap Fermions: Overlap fermions preserve a remnant of chiral symmetry on the lattice. They\nare a powerful tool to investigate the topological structure of the vacuum of\nYang-Mills theory and full QCD. Recent results concerning the localization of\ntopological charge and the localization and local chirality of the overlap\neigenmodes are reported. The charge distribution is radically different, if a\nspectral cut-off for the Dirac eigenmodes is applied. The density q(x) is\nchanging from the scale-a charge density (with full lattice resolution) to the\nultraviolet filtered charge density. The scale-a density, computed on the Linux\ncluster of LRZ, has a singular, sign-coherent global structure of co-dimension\n1 first described by the Kentucky group. We stress, however, the cluster\nproperties of the UV filtered topological density resembling the instanton\npicture. The spectral cut-off can be mapped to a bosonic smearing procedure.\nThe UV filtered field strength reveals a high degree of (anti)selfduality at\n\"hot spots\" of the action. The fermionic eigenmodes show a high degree of local\nchirality. The lowest modes are seen to be localized in low-dimensional\nspace-time regions."
    },
    {
        "anchor": "Convex optimization of contour deformations: We discuss various formal aspects of contour deformations used to alleviate\nsign problems; most importantly, relating these contour deformations to a\ncertain convex optimization problem. As a consequence of this connection we\ndescribe a general method for proving upper bounds on the average phase\nachievable by the contour deformation method. Using this method we show that\nAbelian lattice Yang-Mills in two spacetime dimensions possesses, for many\nvalues of the complex coupling, an exponential sign problem that cannot be\nremoved via any contour deformation.",
        "positive": "Lattice and string worldsheet in AdS/CFT: a numerical study: We consider a possible discretization for the gauge-fixed Green-Schwarz\n(two-dimensional) sigma-model action for the Type IIB superstring and use it\nfor measuring the cusp anomalous dimension of planar $\\mathcal{N}=4$ SYM as\nderived from string theory. We perform lattice simulations employing a Rational\nHybrid Monte Carlo (RHMC) algorithm and a Wilson-like fermion discretization.\nIn this preliminary study, we compare our results with the expected behavior\nfor very large values of $g=\\frac{\\sqrt{\\lambda}}{4\\pi}$, which is the\nperturbative regime of the sigma-model, and find a qualitative agreement at\nfinite lattice spacing. For smaller $g$ the continuum limit is obstructed by a\ndivergence. We also detect a phase in the fermion determinant, whose origin we\nexplain, which for small $g$ leads to a sign problem not treatable via standard\nreweigthing. Results presented here are discussed thoroughly\nin~\\cite{toappear}."
    },
    {
        "anchor": "QCD thermodynamics in the crossover/freeze-out region: We use results from a 6-th order Taylor expansion of the QCD equation of\nstate to construct expansions for cumulants of conserved charge fluctuations\nand their correlations. We show that these cumulants strongly constrain the\nrange of applicability of hadron resonance gas model calculations. We point out\nthat the latter is inappropriate to describe equilibrium properties of QCD at\nzero and non-zero values of the baryon chemical potential already at T~155 MeV.",
        "positive": "Dynamical overlap fermions with increased topological tunnelling: We present two improvements to our previous dynamical overlap HMC algorithm.\nWe introduce a new method of differentiating the eigenvectors of the Kernel\noperator, which removes an instability in the fermionic force. Secondly, by\nsimulating part of the fermion determinant exactly, without pseudo-fermions, we\nare able to increase the rate of topological tunnelling by a factor of more\nthan ten, reducing the auto-correlation."
    },
    {
        "anchor": "Effective constraint potential in lattice Weinberg - Salam model: We investigate lattice Weinberg - Salam model without fermions for the value\nof the Weinberg angle $\\theta_W \\sim 30^o$, and bare fine structure constant\naround $\\alpha \\sim 1/150$. We consider the value of the scalar self coupling\ncorresponding to bare Higgs mass around 150 GeV. The effective constraint\npotential for the zero momentum scalar field is used in order to investigate\nphenomena existing in the vicinity of the phase transition between the physical\nHiggs phase and the unphysical symmetric phase of the lattice model. This is\nthe region of the phase diagram, where the continuum physics is to be\napproached. We compare the above mentioned effective potential (calculated in\nselected gauges) with the effective potential for the value of the scalar field\nat a fixed space - time point. We also calculate the renormalized fine\nstructure constant using the correlator of Polyakov lines and compare it with\nthe one - loop perturbative estimate.",
        "positive": "B_K in Staggered Chiral Perturbation Theory: We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered\nchiral perturbation theory. We find expressions for partially quenched QCD with\nthree sea quarks, quenched QCD, and full QCD with m_u = m_d but not equal to\nm_s. We extend the usual power counting to include the effects of using\nperturbative (rather than non-perturbative) matching factors. Taste breaking\nenters through the O(a^2) terms in the effective action, through O(a^2) terms\nfrom the discretization of operators, and through the truncation of matching\nfactors. These effects cause mixing with several additional operators,\ncomplicating the chiral and continuum extrapolations. In addition to the\nstaggered expressions, we present B_K at next-to-leading order in continuum\npartially quenched chiral perturbation theory for N_f=3 sea quarks with m_u =\nm_d but not equal to m_s."
    },
    {
        "anchor": "Topological susceptibility in (2+1)-flavor lattice QCD with overlap\n  fermion: We determine the topological susceptibility \\chi_t in the\ntopologically-trivial sector generated by lattice simulations of N_f = 2+1 QCD\nwith overlap Dirac fermion, on a 16^3 x 48 lattice with lattice spacing ~ 0.11\nfm, for five sea quark masses m_q ranging from m_s/6 to m_s (where m_s is the\nphysical strange quark mass). The \\chi_t is extracted from the plateau (at\nlarge time separation) of the 2-point and 4-point time-correlation functions of\nthe flavor-singlet pseudoscalar meson \\eta', which arises from the finite size\neffect due to fixed topology. In the small m_q regime, our result of \\chi_t\nagrees with the chiral effective theory. Using the formula \\chi_t =\n\\Sigma(m_u^{-1} + m_d^{-1} + m_s^{-1})^{-1} by Leutwyler-Smilga, we obtain the\nchiral condensate \\Sigma^{MSbar}(2 GeV) = [249(4)(2) MeV]^3.",
        "positive": "Reweighting Lefschetz Thimbles: One of the main challenges in simulations on Lefschetz thimbles is the\ncomputation of the relative weights of contributing thimbles. In this paper we\npropose a solution to that problem by means of computing those weights using a\nreweighting procedure. Besides we present recipes for finding parametrizations\nof thimbles and anti-thimbles for a given theory. Moreover, we study some\napproaches to combine the Lefschetz thimble method with the Complex Langevin\nevolution. Our numerical investigations are carried out by using toy models\namong which we consider a one-site z^4 model as well as a U(1) one-link model."
    },
    {
        "anchor": "Hyperon vector form factor from 2+1 flavor lattice QCD: We present the first result for the hyperon vector form factor f_1 for Xi^0\n-> Sigma^+ l bar{nu} and Sigma^- -> n l bar{nu} semileptonic decays from fully\ndynamical lattice QCD. The calculations are carried out with gauge\nconfigurations generated by the RBC and UKQCD collaborations with (2+1)-flavors\nof dynamical domain-wall fermions and the Iwasaki gauge action at beta=2.13,\ncorresponding to a cutoff 1/a=1.73 GeV. Our results, which are calculated at\nthe lighter three sea quark masses (the lightest pion mass down to\napproximately 330 MeV), show that a sign of the second-order correction of\nSU(3) breaking on the hyperon vector coupling f_1(0) is negative. The tendency\nof the SU(3) breaking correction observed in this work disagrees with\npredictions of both the latest baryon chiral perturbation theory result and\nlarge N_c analysis.",
        "positive": "The $\u03b8$-dependence of the Yang-Mills spectrum from analytic\n  continuation: We study the $\\theta$-dependence of the string tension and of the lightest\nglueball mass in four-dimensional $\\mathrm{SU}(N)$ Yang-Mills theories. More\nprecisely, we focus on the coefficients parametrizing the\n$\\mathcal{O}(\\theta^2)$ dependence of these quantities, which we investigate by\nmeans of numerical simulations of the lattice-discretized theory, carried out\nusing imaginary values of the $\\theta$ parameter. We provide controlled\ncontinuum extrapolations of such coefficients in the $N=3$ case, and we report\nthe results obtained on two fairly fine lattice spacings for $N=6$."
    },
    {
        "anchor": "Minimal doubling and point splitting: Minimally-doubled chiral fermions have the unusual property of a single local\nfield creating two fermionic species. Spreading the field over hypercubes\nallows construction of combinations that isolate specific modes. Combining\nthese fields into bilinears produces meson fields of specific quantum numbers.",
        "positive": "The Coulomb flux tube on the lattice: In Coulomb gauge a longitudinal electric field is generated instantaneously\nwith the creation of a static quark-antiquark pair. The field due to the quarks\nis a sum of two contributions, one from the quark and one from the antiquark,\nand there is no obvious reason that this sum should fall off exponentially with\ndistance from the sources. We show here, however, from numerical simulations in\npure SU(2) lattice gauge theory, that the color Coulomb electric field does in\nfact fall off exponentially with transverse distance away from a line joining\nstatic quark-antiquark sources, indicating the existence of a color Coulomb\nflux tube, and the absence of long-range Coulomb dipole fields."
    },
    {
        "anchor": "Excited bottomonia in quark-gluon plasma from lattice QCD: We present the first lattice QCD study of up to $3S$ and $2P$ bottomonia at\nnon-zero temperatures. Correlation functions of bottomonia were computed using\nnovel bottomonium operators and a variational technique, within the lattice\nnon-relativistic QCD framework. We analyzed the bottomonium correlation\nfunctions based on simple physically-motivated spectral functions. We found\nevidence of sequential in-medium modifications, in accordance with the sizes of\nthe bottomonium states.",
        "positive": "Chiral-spin symmetry of the meson spectral function above $T_c$: Recently, via calculation of spatial correlators of $J=0,1$ isovector\noperators using a chirally symmetric Dirac operator within $N_F=2$ QCD, it has\nbeen found that QCD at temperatures $T_c - 3 T_c$ is approximately $SU(2)_{CS}$\nand $SU(4)$ symmetric. The latter symmetry suggests that the physical degrees\nof freedom are chirally symmetric quarks bound by the chromoelectric field into\ncolor singlet objects without chromomagnetic effects. This regime of QCD has\nbeen referred to as a Stringy Fluid. Here we calculate correlators for\npropagation in time direction at a temperature slightly above $T_c$ and find\nthe same approximate symmetries. This means that the meson spectral function is\nchiral-spin and $SU(4)$ symmetric."
    },
    {
        "anchor": "Overlap formula for the chiral multiplet: The vacuum overlap formalism is extended to describe the supersymmetric\nmultiplet of a Weyl fermion, a complex scalar boson and an auxiliary field in\nthe case without interaction, based on the fact that supersymmetry can be\nmaintained upto quadratic terms by introducing bosonic species doublers. We\nalso obtain a local action which describes the chiral multiplet and discuss its\nsymmetry structure. It is shown that, besides the manifest supersymmetry, the\naction possesses a chiral symmetry of the type given by L\\\"uscher and analogous\nbosonic symmetries which may be regarded as independent infinitesimal rotations\nof complex phases of the scalar and the auxiliary fields. This implies that the\n$U(1) \\times U(1)_R$ symmetry of the chiral multiplet can be exact on the\nlattice.",
        "positive": "Screening in Hot SU(2) Gauge Theory and Propagators in 3d Adjoint Higgs\n  model: We investigate the large distance behavior of the electric and magnetic\npropagators of hot SU(2) gauge theory in different gauges using lattice\nsimulations of the full 4d theory and the effective, dimensionally reduced 3d\ntheory. A comparison of the 3d and 4d data for the propagators suggests that\ndimensional reduction works surprisingly well down to temperatures T=2 T_c. A\ndetailed study of the volume dependence of magnetic propagators is performed.\nThe electric propagators show exponential decay at large distances in all\ngauges considered and a possible gauge dependence of the electric screening\nmass turns out to be statistically insignificant."
    },
    {
        "anchor": "High Precision Statistical Landau Gauge Lattice Gluon Propagator\n  Computation: We report on results for the Landau gauge gluon propagator computed from\nlarge statistical ensembles and look at the compatibility of the results with\nthe Gribov-Zwanziger tree level prediction for its refined and very refined\nversions. Our results show that the data is well described by the tree level\nestimate only up to momenta $p \\lesssim 1$ GeV, while clearly favouring the\nso-called Refined Gribov-Zwanziger scenario. We also provide a global fit of\nthe lattice data which interpolates between the above scenario at low momenta\nand the usual continuum one-loop renormalisation improved perturbation theory\nafter introducing an infrared log-regularizing term.",
        "positive": "The flat phase of fixed-connectivity membranes: The statistical mechanics of flexible two-dimensional surfaces (membranes)\nappears in a wide variety of physical settings. In this talk we discuss the\nsimplest case of fixed-connectivity surfaces. We first review the current\ntheoretical understanding of the remarkable flat phase of such membranes. We\nthen summarize the results of a recent large scale Monte Carlo simulation of\nthe simplest conceivable discrete realization of this system \\cite{BCFTA}. We\nverify the existence of long-range order, determine the associated critical\nexponents of the flat phase and compare the results to the predictions of\nvarious theoretical models."
    },
    {
        "anchor": "Implications of gradient flow on the static force: We use gradient flow to compute the static force based on a Wilson loop with\na chromoelectric field insertion. The result can be compared on one hand to the\nstatic force from the numerical derivative of the lattice static energy, and on\nthe other hand to the perturbative calculation, allowing a precise extraction\nof the $\\Lambda_0$ parameter. This study may open the way to gradient flow\ncalculations of correlators of chromoelectric and chromomagnetic fields, which\ntypically arise in the nonrelativistic effective field theory factorization.",
        "positive": "One-loop perturbative coupling of $A$ and $A_\\star$ through the chiral\n  overlap operator: We study the one-loop effective action defined by the chiral overlap operator\nin the four-dimensional lattice formulation of chiral gauge theories by\nGrabowska and Kaplan. In the tree-level continuum limit, the left-handed\ncomponent of the fermion is coupled only to the original gauge field~$A$, while\nthe right-handed one is coupled only to~$A_\\star$, which is given by the\ngradient flow of~$A$ with infinite flow time. In this paper, we show that the\ncontinuum limit of the one-loop effective action contains local interaction\nterms between $A$ and~$A_\\star$, which do not generally vanish even if the\ngauge representation of the fermion is anomaly free. We argue that the presence\nof such interaction terms can be regarded as undesired gauge symmetry-breaking\neffects in the formulation."
    },
    {
        "anchor": "Spectral functions of charmonium with 2+1 flavours of dynamical quarks: Finite temperature charmonium spectral functions in the pseudoscalar(PS) and\nvector(V) channels are studied in lattice QCD with 2+1 flavours of dynamical\nWilson quarks, on fine isotropic lattices (with a lattice spacing of 0.057fm),\nwith a non-physical pion mass of 545MeV. The highest temperature studied is\napproximately 1.4Tc. Up to this temperature no significant variation of the\nspectral function is seen in the PS channel. The V channel shows some\ntemperature dependence, which seems to be consistent with a temperature\ndependent low frequency peak related to heavy quark transport, plus a\ntemperature independent term at omega > 0. These results are in accord with\nprevious calculations using the quenched approximation.",
        "positive": "Bayesian-Wilson coefficients in lattice QCD computations of valence PDFs\n  and GPDs: We propose an analysis method for the leading-twist operator product\nexpansion based lattice QCD determinations of the valence parton distribution\nfunction (PDF). In the first step, we determine the confidence-intervals of the\nleading-twist $\\overline{\\mathrm{MS}}$ Wilson coefficients, $C_n(\\mu^2 z^2)$,\nof the equal-time bilocal quark bilinear, given the lattice QCD matrix element\nof Ioffe-time distribution for a particular hadron $H$ as well as the prior\nknowledge of the valence PDF, $f(x,\\mu)$ of the hadron $H$ determined via\nglobal fit from the experimental data. In the next step, we apply the\nnumerically estimated $C_n$ in the lattice QCD determinations of the valence\nPDFs of other hadrons, and for the zero-skewness generalized parton\ndistribution (GPD) of the same hadron $H$ at non-zero momentum transfers. Our\nproposal still assumes the dominance of leading-twist terms, but it offers a\npragmatic alternative to the usage of perturbative Wilson coefficients and\ntheir associated higher-loop uncertainties such as the effect of all-order\nlogarithms at larger sub-Fermi quark-antiquark separations $z$."
    },
    {
        "anchor": "Improved Lattice Actions with Chemical Potential: We give a prescription how to include a chemical potential \\mu into a general\nlattice action. This inclusion does not cause any lattice artifacts. Hence its\napplication to an improved - or even perfect - action at \\mu =0 yields an\nimproved resp. perfect action at arbitrary \\mu. For short-ranged improved\nactions, a good scaling behavior holds over a wide region, and the upper bound\nfor the baryon density - which is known for the standard lattice actions - can\nbe exceeded.",
        "positive": "The QCD equation of state in background magnetic fields: We determine the equation of state of 2+1-flavor QCD with physical quark\nmasses, in the presence of a constant (electro)magnetic background field on the\nlattice. To determine the free energy at nonzero magnetic fields we develop a\nnew method, which is based on an integral over the quark masses up to\nasymptotically large values where the effect of the magnetic field can be\nneglected. The method is compared to other approaches in the literature and\nfound to be advantageous for the determination of the equation of state up to\nlarge magnetic fields. Thermodynamic observables including the longitudinal and\ntransverse pressure, magnetization, energy density, entropy density and\ninteraction measure are presented for a wide range of temperatures and magnetic\nfields, and provided in ancillary files. The behavior of these observables\nconfirms our previous result that the transition temperature is reduced by the\nmagnetic field. We calculate the magnetic susceptibility and permeability,\nverifying that the thermal QCD medium is paramagnetic around and above the\ntransition temperature, while we also find evidence for weak diamagnetism at\nlow temperatures."
    },
    {
        "anchor": "A realistic heat bath: theory and application to kink-antikink dynamics: We propose a new method of studying a real-time canonical evolution of\nfield-theoretic systems with boundary coupling to a realistic heat bath. In the\nfree-field case the method is equivalent to an infinite extension of the system\nbeyond the boundary, while in the interacting case the extension of the system\nis done in linear approximation. We use this technique to study kink-antikink\ndynamics in $\\varphi^4$ field theory in 1+1 dimensions.",
        "positive": "Gluon Parton Distribution of the Pion from Lattice QCD: We present the first determination of the $x$-dependent pion gluon\ndistribution from lattice QCD using the pseudo-PDF approach. We use lattice\nensembles with 2+1+1 flavors of highly improved staggered quarks (HISQ),\ngenerated by MILC Collaboration, at two lattice spacings $a\\approx 0.12$ and\n0.15~fm and three pion masses $M_\\pi\\approx 220$, 310 and 690 MeV. We use\nclover fermions for the valence action and momentum smearing to achieve pion\nboost momentum up to 2.29 GeV. We find that the dependence of the pion gluon\nparton distribution on lattice spacing and pion mass is mild. We compare our\nresults from the lightest pion mass ensemble with the determination by JAM and\nxFitter global fits."
    },
    {
        "anchor": "Optimization of the Brillouin operator on the KNL architecture: Experiences with optimizing the matrix-times-vector application of the\nBrillouin operator on the Intel KNL processor are reported. Without adjustments\nto the memory layout, performance figures of 360 Gflop/s in single and 270\nGflop/s in double precision are observed. This is with N_c=3 colors, N_v=12\nright-hand-sides, N_{thr}=256 threads, on lattices of size 32^3*64, using\nexclusively OMP pragmas. Interestingly, the same routine performs quite well on\nIntel Core i7 architectures, too. Some observations on the much harder Wilson\nfermion matrix-times-vector optimization problem are added.",
        "positive": "Gauge fixed domain wall fermions on lattice at small Yukawa coupling: Gauge fixed domain wall fermions are investigated in the reduced model at\nsmall Yukawa couplings. We present chiral propagators at the waveguide\nboundaries using quenched numerical simulations and analytic methods. There is\nno evidence of mirror chiral modes at the waveguide boundaries."
    },
    {
        "anchor": "Monopole percolation in scalar QED: Monopole Percolation was first introduced in the study of the non-compact\nlattice QED in both, the pure case and coupled to Higgs fields. Monopole\npercolation has been also observed coupled to the monopole condensation in the\nstudy of the pure gauge compact QED. We present here the results coming from\nthe analysis of the role of the monopole percolation in the coupled gauge-higgs\ncompact QED.",
        "positive": "Nucleon Axial and Electromagnetic Form Factors: We present results for the isovector axial, induced pseudoscalar, electric,\nand magnetic form factors of the nucleon. The calculations were done using\n$2+1+1$-flavor HISQ ensembles generated by the MILC collaboration with lattice\nspacings $a \\approx$ 0.12, 0.09, 0.06$\\mathrm{fm}$ and pion masses $M_\\pi\n\\approx$ 310, 220, 130$\\mathrm{MeV}$. Excited-states contamination is\ncontrolled by using four-state fits to two-point correlators and by comparing\ntwo- versus three-states in three-point correlators. The $Q^2$ behavior is\nanalyzed using the model independent z-expansion and the dipole ansatz. Final\nresults for the charge radii and magnetic moment are obtained using a\nsimultaneous fit in $M_\\pi$, lattice spacing $a$ and finite volume."
    },
    {
        "anchor": "The lattice infrared Landau gauge gluon propagator: from finite volume\n  to the infinite volume: The Landau gauge lattice gluon propagator is discussed for different sets of\nlattices. Particular attention is given to its infrared properties. Our results\nshow that the lattice propagator can be made compatible with either the\ndecoupling-like or the scaling-like solution of the Dyson-Schwinger equations.\nFurthermore, the analysis of the Cucchieri-Mendes bounds is performed\nonsidering large volume simulations and the Oliveira-Silva ratios are computed.\nIf the first do not give a clear answer about the value of D(0), the second\nmethod favors a $D(0) = 0$. Finally, the SU(3) and SU(2) propagators are\ncompared in the infrared. It comes out that the propagators are different\nalthough the infrared exponents seem to be similar. The analysis suggests a\nscaling behaviour $D(0) \\sim N$ with the gauge group SU(N).",
        "positive": "Entanglement Entropy in Pure $Z_2$ Gauge Lattices: We show that the Hilbert space of physical states on a pure $Z_2$ gauge\nlattice in $1 + 1$ and $2 + 1$ dimensions is geometrically separable if the\nfundamental physical degrees of freedom are taken to be the plaquettes. This\nresults in a physical entanglement entropy that is not affected by gauge\nfixing. We introduce a lattice model that is physically equivalent to the\noriginal and whose entanglement entropy, calculated using link degrees of\nfreedom, is the same as the entanglement entropy calculated using physical\nstates. We also show that, for non-physical gauge link states, entanglement\nentropy quantifies constraints between gauge choices in plaquettes adjacent to\nthe boundary."
    },
    {
        "anchor": "Helium Nuclei in Quenched Lattice QCD: We present results for the binding energies for He and ^3He nuclei calculated\nin quenched lattice QCD at the lattice spacing of a = 0.128 fm with a heavy\nquark mass corresponding to m_pi = 0.8 GeV. Enormous computational cost for the\nnucleus correlation functions is reduced by avoiding redundancy of equivalent\ncontractions stemming from permutation symmetry of protons or neutrons in the\nnucleus and various other symmetries. To distinguish a bound state from an\nattractive scattering state, we investigate the volume dependence of the energy\ndifference between the nucleus and the free multi-nucleon states by changing\nthe spatial extent of the lattice from 3.1 fm to 12.3 fm. A finite energy\ndifference left in the infinite spatial volume limit leads to the conclusion\nthat the measured ground states are bounded. It is also encouraging that the\nmeasured binding energies and the experimental ones show the same order of\nmagnitude.",
        "positive": "One-loop matching of lattice and continuum heavy-light axial vector\n  currents using NRQCD: The temporal component of the heavy-light axial vector current is constructed\nto one-loop order in perturbation theory and to order 1/M, where M is the heavy\nquark mass, in terms of operators suitable for use in lattice simulations of B\nand D mesons. The O(a)-improved clover action is used for the massless light\nquark, where a is the lattice spacing, and propagation of the heavy quark is\ndescribed by a nonrelativistic lattice action."
    },
    {
        "anchor": "Anomalous discrete chiral symmetry in the Gross-Neveu model and loop gas\n  simulations: We investigate the discrete chiral transformation of a Majorana fermion on a\ntorus. Depending on the boundary conditions the integration measure can change\nsign. Taking this anomalous behavior into account we define a chiral order\nparameter as a ratio of partition functions with differing boundary conditions.\nThen the lattice realization of the Gross-Neveu model with Wilson fermions is\nsimulated using the recent `worm' technique on the loop gas or all-order\nhopping representation of the fermions. An algorithm is formulated that\nincludes the Gross-Neveu interaction for N fermion species. The critical line\nm_c(g) is constructed for a range of couplings at N = 6 and for N = 2, the\nThirring model, as examples.",
        "positive": "Properties of minimally doubled fermions: Most quark actions in lattice QCD encounter difficulties with chiral symmetry\nand its spontaneous breakdown. Minimally doubled fermions (MDF) are a category\nof strictly local chiral lattice fermions, whose continuum limit reproduces two\ndegenerate quark flavours. The two poles of their Dirac operator are aligned\nsuch that symmetries under charge conjugation or reflection of one particular\ndirection are explictly broken at finite lattice spacing. Properties of MDF are\nscrutinised with regard to broken symmetry and meson spectrum to discern their\nsuitability for numerical studies of QCD. Interactions induce anisotropic\noperator mixing for MDF. Hence, restoration of broken symmetries in the\ncontinuum limit requires three counterterms, one of which is power-law\ndivergent. Counterterms and operator mixing are studied perturbatively for two\nvariants of MDF. Two independent non-perturbative procedures for removal of the\npower-law divergence are developed by means of a numerical study of hadronic\nobservables for one variant of MDF in quenched approximation. Though three out\nof four pseudoscalar mesons are affected by lattice artefacts, the spectrum's\ncontinuum limit is consistent with two-flavour QCD. Thus, suitability of MDF\nfor numerical studies of QCD in the quenched approximation is demonstrated."
    },
    {
        "anchor": "Faster Fermions in the Tempered Hybrid Monte Carlo Algorithm: Tempering is used to change the quark mass while remaining in equilibrium\nbetween the trajectories of a standard hybrid Monte Carlo simulation of four\nflavours of staggered fermions. The algorithm is faster for small enough quark\nmasses, and particularly so when more than one mass is required.",
        "positive": "Large-N_f chiral transition in the Yukawa model: We investigate the finite-temperature behavior of the Yukawa model in which\n$N_{f}$ fermions are coupled with a scalar field $\\phi$ in the limit $N_f \\to\n\\infty$. Close to the chiral transition the model shows a crossover between\nmean-field behavior (observed for $N_f = \\infty$) and Ising behavior (observed\nfor any finite $N_f$). We show that this crossover is universal and related to\nthat observed in the weakly-coupled $\\phi^4$ theory. It corresponds to the\nrenormalization-group flow from the unstable Gaussian fixed point to the stable\nIsing fixed point. This equivalence allows us to use results obtained in field\ntheory and in medium-range spin models to compute Yukawa correlation functions\nin the crossover regime."
    },
    {
        "anchor": "Lattice QCD: concepts, techniques and some results: I give a brief introduction to lattice QCD for non-specialists.",
        "positive": "Radiative improvement of the lattice NRQCD action using the background\n  field method and application to the hyperfine splitting of quarkonium states: We present the first application of the background field method to\nNon-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop\nradiative corrections to the coefficients of the NRQCD action in a manifestly\ngauge-covariant manner. The coefficient of the $\\sigma\\cdot B$ term in the\nNRQCD action is computed at the one-loop level; the resulting shift of the\nhyperfine splitting of bottomonium is found to bring the lattice predictions in\nline with experiment."
    },
    {
        "anchor": "Renormalization of quark propagator, vertex functions and twist-2\n  operators from twisted-mass lattice QCD at $N_f$=4: We present a precise non-perturbative determination of the renormalization\nconstants in the mass independent RI'-MOM scheme. The lattice implementation\nuses the Iwasaki gauge action and four degenerate dynamical twisted mass\nfermions. The gauge configurations are provided by the ETM Collaboration.\nRenormalization constants for scalar, pseudo-scalar, vector and axial\noperators, as well as the quark propagator renormalization, are computed at\nthree different values of the lattice spacing, two volumes and several twisted\nmass parameters. The method we developed allows for a precise cross-check of\nthe running, thanks to the particular proper treatment of hypercubic artifacts.\nResults for the twist-2 operator $O_{44}$ are also presented.",
        "positive": "Spectral properties and chiral symmetry violations of (staggered) domain\n  wall fermions in the Schwinger model: We follow up on a suggestion by Adams and construct explicit domain wall\nfermion operators with staggered kernels. We compare different domain wall\nformulations, namely the standard construction as well as Borici's modified and\nChiu's optimal construction, utilizing both Wilson and staggered kernels. In\nthe process, we generalize the staggered kernels to arbitrary even dimensions\nand introduce both truncated and optimal staggered domain wall fermions. Some\nnumerical investigations are carried out in the (1+1)-dimensional setting of\nthe Schwinger model, where we explore spectral properties of the bulk,\neffective and overlap Dirac operators in the free-field case, on quenched\nthermalized gauge configurations and on smooth topological configurations. We\ncompare different formulations using the effective mass, deviations from\nnormality and violations of the Ginsparg-Wilson relation as measures of\nchirality."
    },
    {
        "anchor": "The Strong Coupling from Quarkonia: The status of determinations of $\\al_s$ from quarkonia using lattice QCD is\nreviewed. We compare the results with those obtained from perturbative QCD.",
        "positive": "New descriptions of lattice SU(N) Yang-Mills theory towards quark\n  confinement: We give new descriptions of lattice SU(N) Yang-Mills theory in terms of new\nlattice variables. The validity of such descriptions has already been\ndemonstrated in the SU(2) Yang-Mills theory by our previous works from the\nviewpoint of defining and extracting topological degrees of freedom such as\ngauge-invariant magnetic monopoles and vortices which play the dominant role in\nquark confinement. In particular, we have found that the SU(3) lattice\nYang-Mills theory has two possible options, maximal and minimal: The existence\nof the minimal option has been overlooked so far, while the maximal option\nreproduces the conventional SU(3) Cho-Faddeev-Niemi-Shabanov decomposition in\nthe naive continuum limit. The new description gives an important framework for\nunderstanding the mechanism of quark confinement based on the dual\nsuperconductivity."
    },
    {
        "anchor": "A Magnetic Monopole in Pure SU(2) Gauge Theory: The magnetic monopole in euclidean pure SU(2) gauge theory is investigated\nusing a background field method on the lattice.\n  With Monte Carlo methods we study the mass of the monopole in the full\nquantum theory.\n  The monopole background under the quantum fluctuations is induced by imposing\nfixed monopole boundary conditions on the walls of a finite lattice volume.\n  By varying the gauge coupling it is possible to study monopoles with scales\nfrom the hadronic scale up to high energies.\n  The results for the monopole mass are consistent with a conjecture we made\npreviously in a realization of the dual superconductor hypothesis of\nconfinement.",
        "positive": "Visualizations of Centre Vortex Structure in Lattice Simulations: The structure of centre vortices in SU(3) gauge-field configurations is\nexamined through modern visualization techniques. Centre vortices are\nidentified through gauge transformations maximizing the centre of the gauge\ngroup. Focusing on the thin vortices identified by Wilson loops having a\nnon-trivial centre phase, the vortex structure is illustrated through\nrenderings of oriented spatial plaquettes. Time oriented plaquettes are\nillustrated by identifying spatial links associated with these non-trivial\nplaquettes. The results illustrate an important role for the branching of SU(3)\ncentre vortices, possibly through monopole anti-monopole dynamics. Of\nparticular interest is the correlation of the vortex structure and the\ntopological-charge structure of the gauge fields, vital to dynamical chiral\nsymmetry breaking and its associated mass generation. Singular points, where\nthe projected vortex structure contains non-trivial centre phases in associated\nplaquettes spanning all four dimensions, are observed within the regions of\nnontrivial topological charge density calculated on the original Monte-Carlo\ngenerated configurations. The results provide new insights into the role of\ncentre vortices in underpinning non-trivial topology in gauge fields. They\nreveal how the removal of centre-vortices necessarily destroys non-trivial\ntopology and destabilizes would-be instantons under smoothing algorithms. The\nobserved correlations further strengthen the idea that centre vortices are the\nseeds of dynamical chiral symmetry breaking."
    },
    {
        "anchor": "The running coupling of 8 flavors and 3 colors: We compute the renormalized running coupling of SU(3) gauge theory coupled to\nN_f = 8 flavors of massless fundamental Dirac fermions. The recently proposed\nfinite volume gradient flow scheme is used. The calculations are performed at\nseveral lattice spacings allowing for a controlled continuum extrapolation. The\nresults for the discrete beta-function show that it is monotonic without any\nsign of a fixed point in the range of couplings we cover. As a cross check the\ncontinuum results are compared with the well-known perturbative continuum\nbeta-function for small values of the renormalized coupling and perfect\nagreement is found.",
        "positive": "Calculation of Nucleon Electric Dipole Moments Induced by Quark\n  Chromo-Electric Dipole Moments and the QCD $\u03b8$-term: Electric dipole moments (EDMs) of nucleons and nuclei, which are sought as\nevidence of CP violation, require lattice calculations to connect constraints\nfrom experiments to limits on the strong CP violation within QCD or CP\nviolation introduced by new physics from beyond the standard model. Nucleon EDM\ncalculations on a lattice are notoriously hard due to large statistical noise,\nchiral symmetry violating effects, and potential mixing of the EDM and the\nanomalous magnetic moment of the nucleon. In this report, details of ongoing\nlattice calculations of proton and neutron EDMs induced by the QCD\n$\\theta$-term and the quark chromo-EDM, the lowest-dimension effective\nCP-violating quark-gluon interaction are presented. Our calculation employs\nchiral-symmetric fermion discretization. An assessment of feasibility of\nnucleon EDM calculations at the physical point is discussed."
    },
    {
        "anchor": "Colour field flux tubes and Casimir scaling for various SU(3)\n  representations: We investigate the QCD flux tubes linking static colour charges of different\nSU(3) representations, relevant to the understanding of confinement and of the\nLund strings of Heavy Ion Collisions. The colour field densities, the Casimir\nscaling factors and the widths for the flux tubes of the first five different\nrepresentations are computed in quenched SU(3) lattice QCD. This study is\nrelevant to understand the mechanisms of confinement and also the flux tubes\nutilized in the Lund Model and in other models of Heavy Ion Collisions.",
        "positive": "Recent topics of infrared effective lattice QCD: Three topics concerning infrared effective lattice QCD are discussed.\n(1)Perfect lattice action of infrared SU(3) QCD and perfect operators for the\nstatic potential are analytically given when we assume two-point monopole\ninteractions alone. The assumption seems to be justified from numerical\nanalyses of pure SU(3) QCD in maximally abelian gauge. (2)Gauge invariance of\nmonopole dominance can be proved theoretically if the gauge invariance of\nabelian dominance is proved. The gauge invariance of monopole condensation\nleads us to confinement of abelian neutral but color octet states after abelian\nprojection. (3)A stochastic gauge fixing method is developed to study the gauge\ndependence of the Abelian projection, which interpolates between the maximally\nabelian (MA) gauge and no gauge fixing. Abelian dominance for the heavy quark\npotential holds even in the gauge which is far from Maximally Abelian one."
    },
    {
        "anchor": "Discrete Abelian lattice gauge theories on a ladder and their dualities\n  with quantum clock models: We study a duality transformation from the gauge-invariant subspace of a\n$\\mathbb{Z}_N$ lattice gauge theory on a two-leg ladder geometry to an\n$N$-clock model on a single chain. The main feature of this mapping is the\nemergence of a longitudinal field in the clock model, whose value depends on\nthe superselection sector of the gauge model, implying that the different\nsectors of the gauge theory can show quite different phase diagrams. In order\nto investigate this and see if confined phases might emerge, we perform a\nnumerical analysis for $N = 2, 3, 4$, using exact diagonalization and DMRG.",
        "positive": "O(3) model with Nienhuis action: We study the O(3) sigma model in $D=2$ on the lattice with a Boltzmann weight\nlinearized in $\\beta$ on each link. While the spin formulation now suffers from\na sign-problem the equivalent loop model remains positive and becomes\nparticularly simple. By studying the transfer matrix and by performing Monte\nCarlo simulations in the loop form we study the mass gap coupling in a step\nscaling analysis. The question addressed is, whether or not such a simplified\naction still has the right universal continuum limit. If the answer is\naffirmative this would be helpful in widening the applicability of worm\nalgorithm methods."
    },
    {
        "anchor": "Finite Temperature Quark Confinement: Confinement may be more easily demonstrated at finite temperature using the\nPolyakov loop than at zero temperature using the Wilson loop. A natural\nmechanism for confinement can arise via the coupling of the adjoint Polyakov\nloop to F_{mu nu}^2. We demonstrate this mechanism with a one-loop calculation\nof the effective potential for SU(2) gluons in a background field consisting of\na non-zero color magnetic field and a non-trivial Polyakov loop. The color\nmagnetic field drives the Polyakov loop to non-trivial behavior, and the\nPolyakov loop can remove the well-known tachyonic mode associated with the\nSaviddy vacuum. Minimizing the real part of the effective potential leads to\nconfinement, as determined by the Polyakov loop. Unfortunately, we cannot\narrange for simultaneous stability and confinement for this simple class of\nfield configurations. We show for a large class of abelian background fields\nthat at one loop tachyonic modes are necessary for confinement.",
        "positive": "Generative models for scalar field theories: how to deal with poor\n  scaling?: Generative models, such as the method of normalizing flows, have been\nsuggested as alternatives to the standard algorithms for generating lattice\ngauge field configurations. Studies with the method of normalizing flows\ndemonstrate the proof of principle for simple models in two dimensions.\nHowever, further studies indicate that the training cost can be, in general,\nvery high for large lattices. The poor scaling traits of current models\nindicate that moderate-size networks cannot efficiently handle the inherently\nmulti-scale aspects of the problem, especially around critical points. We\nexplore current models with limited acceptance rates for large lattices and\nexamine new architectures inspired by effective field theories to improve\nscaling traits. We also discuss alternative ways of handling poor acceptance\nrates for large lattices."
    },
    {
        "anchor": "The onset and deconfinement transitions in two-colour QCD: We study two-colour QCD with two flavours of Wilson fermion at non-zero\nchemical potential mu and zero temperature. We find evidence of two separate\ntransitions: an onset transition at mu ~ m_pi/2 where quark number and energy\ndensities increase from zero; and a deconfinement transition at higher mu. The\nmu-dependence of the number and energy densities and the diquark condensate\nindicate that a Fermi surface is formed and that BCS rather than Bose-Einstein\ncondensation dominates at the quark mass considered here, especially beyond the\ndeconfinement transition.",
        "positive": "Canonical Approach to Ginsparg-Wilson Fermion: Based upon the lattice Dirac operator satisfying the Ginsparg-Wilson\nrelation, we investigate canonical formulation of massless fermion on the\nspatial lattice. For free fermion system exact chiral symmetry can be\nimplemented without species doubling. In the presence of gauge couplings the\nchiral symmetry is violated. We show that the divergence of the axial vector\ncurrent is related to the chiral anomaly in the classical continuum limit."
    },
    {
        "anchor": "Lee-Yang zeroes in the one flavour massive lattice Schwinger model: We study the partition function of the model formulated with Wilson fermions\nwith only one species, both analytically and numerically. At strong coupling we\nconstruct the solution for lattice size up to $8\\times 8$, a polynomial in the\nhopping parameter up to $O(\\ka^{128})$. At $\\be>0$ we evaluate the expectation\nvalue of the fermion determinant for complex values of $\\ka$. From the Lee-Yang\nzeroes we find support for the existence of a line of phase transitions from\n$(\\be=0, \\ka\\simeq 0.38)$ up to $(\\be=\\infty, \\ka=1/4)$.",
        "positive": "Renormalization of the Polyakov loop with gradient flow: We use the gradient flow for the renormalization of the Polyakov loop in\nvarious representations. Using 2+1 flavor QCD with highly improved staggered\nquarks and lattices with temporal extents of $N_\\tau=6$, $8$, $10$ and $12$ we\ncalculate the renormalized Polyakov loop in many representations including\nfundamental, sextet, adjoint, decuplet, 15-plet, 24-plet and 27-plet. This\napproach allows for the calculations of the renormalized Polyakov loops over a\nlarge temperature range from $T=116$ MeV up to $T=815$ MeV, with small errors\nnot only for the Polyakov loop in fundamental representation, but also for the\nPolyakov loops in higher representations. We compare our results with standard\nrenormalization schemes and discuss the Casimir scaling of the Polyakov loops."
    },
    {
        "anchor": "Magnetic Catalysis in Graphene: One of the most important developments in condensed matter physics in recent\nyears has been the discovery and characterization of graphene. A\ntwo-dimensional layer of Carbon arranged in a hexagonal lattice, graphene\nexhibits many interesting electronic properties, most notably that the low\nenergy excitations behave as massless Dirac fermions. These excitations\ninteract strongly via the Coulomb interaction and thus non-perturbative methods\nare necessary. Using methods borrowed from lattice QCD, we study the graphene\neffective theory in the presence of an external magnetic field. Graphene, along\nwith other $(2+1)$-dimensional field theories, has been predicted to undergo\nspontaneous breaking of flavor symmetry including the formation of a gap as a\nresult of the external magnetic field. This phenomenon is known as magnetic\ncatalysis. Our study investigates magnetic catalysis using a fully\nnon-perturbative approach.",
        "positive": "Does The Lattice Zero Momentum Gluon Propagator for Pure Gauge SU(3)\n  Yang-Mills Theory Vanish in the Infinite Volume Limit?: The Cucchieri-Mendes bounds for the gluon propagator are discussed for the\nfour dimensional pure gauge SU(3) theory. Assuming a pure power law dependence\non the inverse of the lattice volume, the lattice data gives a vanishing zero\nmomentum gluon propagator in the infinite volume limit. Our investigation shows\nthat this result is robust against variations of the lattice volumes and\ncorrections to the power law. Moreover, it is consistent with the\nGribov-Zwanziger horizon condition and contradicts the SU(2) analysis, which\nassumed the same type of dependence on the inverse of the volume. Our analysis\nconsiders also more general ansatze that, although not conclusive, open the\npossibility of having $D(0) \\ne 0$ in the infinite volume limit. A solution to\nthis puzzle requires further investigations."
    },
    {
        "anchor": "Fast Evaluation of Zolotarev Coefficients: We review the theory of elliptic functions leading to Zolotarev's formula for\nthe sign function over the range (\\epsilon \\leq|x| \\leq1). We show how Gauss'\narithmetico-geometric mean allows us to evaluate elliptic functions cheaply,\nand thus to compute Zolotarev coefficients ``on the fly'' as a function of\n(\\epsilon). This in turn allows us to calculate the matrix functions (\\sgn H),\n(\\sqrt H), and (1/\\sqrt H) both quickly and accurately for any Hermitian matrix\n(H) whose spectrum lies in the specified range.",
        "positive": "Twisted supersymmetries in lattice ${\\cal N}=4$ super Yang-Mills theory: Recently it has been shown how a topologically twisted version of ${\\cal\nN}=4$ super Yang-Mills may be discretized in such a way as to preserve one\nscalar supersymmetry at nonzero lattice spacing. The remaining fifteen\nsupersymmetries are broken by terms of ${\\cal O}(a)$ where $a$ is the lattice\nspacing. One would like to know whether these remaining supersymmetries are\nregained in the continuum limit $a \\to 0$ and, if not, how much tuning of the\ncouplings in the lattice action is required. In this paper we derive the form\nof these additional twisted supersymmetries by combining a set of discrete\nR-symmetries of the continuum theory with the action of the scalar\nsupersymmetry. We then argue that restoration of rotational symmetry in the\ncontinuum limit of the lattice theory likely implies restoration of R-symmetry\nand hence should lead to an automatic enhancement to the full ${\\cal N}=4$\nsupersymmetry without further fine-tuning."
    },
    {
        "anchor": "Improving the improved action: We investigate the construction of improved actions by the Monte Carlo\nRenormalization Group method in the context of SU(2) gauge theory utilizing\ndifferent decimation procedures and effective actions. We demonstrate that the\nbasic self-consistency requirement for correct application of MCRG, i.e. that\nthe decimated configurations are equilibrium configurations of the adopted form\nof the effective action, can only be achieved by careful fine-tuning of the\nchoice of decimation prescription and/or action.",
        "positive": "$\u039b_c \\to \u039b\\ell^+ \u03bd_\\ell$ form factors and decay rates\n  from lattice QCD with physical quark masses: The first lattice QCD calculation of the form factors governing $\\Lambda_c\n\\to \\Lambda \\ell^+ \\nu_\\ell$ decays is reported. The calculation was performed\nwith two different lattice spacings and includes one ensemble with a pion mass\nof 139(2) MeV. The resulting predictions for the $\\Lambda_c \\to \\Lambda e^+\n\\nu_e$ and $\\Lambda_c \\to \\Lambda \\mu^+ \\nu_\\mu$ decay rates divided by\n$|V_{cs}|^2$ are $0.2007(71)(74)\\:{\\rm ps}^{-1}$ and $0.1945(69)(72)\\:{\\rm\nps}^{-1}$, respectively, where the two uncertainties are statistical and\nsystematic. Taking the Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ from\na global fit and the $\\Lambda_c$ lifetime from experiments, this translates to\nbranching fractions of $\\mathcal{B}(\\Lambda_c\\to\\Lambda\ne^+\\nu_e)=0.0380(19)_{\\rm LQCD\\:\\:}(11)_{\\tau_{\\Lambda_c}}$ and\n$\\mathcal{B}(\\Lambda_c\\to\\Lambda \\mu^+\\nu_\\mu)=0.0369(19)_{\\rm\nLQCD\\:\\:}(11)_{\\tau_{\\Lambda_c}}$. These results are consistent with, and two\ntimes more precise than, the measurements performed recently by the BESIII\nCollaboration. Using instead the measured branching fractions together with the\nlattice calculation to determine the CKM matrix element gives $|V_{cs}|=\n0.949(24)_{\\rm LQCD\\:\\:}(14)_{\\tau_{\\Lambda_c}}(49)_{\\mathcal{B}}$."
    },
    {
        "anchor": "Effective Polyakov Loop Dynamics for Finite Temperature G(2)\n  Gluodynamics: Based on the strong coupling expansion we obtain effective 3-dimensional\nmodels for the Polyakov loop in finite-temperature G_2 gluodynamics. The\nSvetitsky-Jaffe conjecture relates the resulting continuous spin models with\nG_2 gluodynamics near phase transition points. In the present work we analyse\nthe effective theory in leading order with the help of a generalised mean field\napproximation and with detailed Monte-Carlo simulations. In addition we derive\na Potts-type discrete spin model by restricting the characters of the Polyakov\nloops to the three extremal points of the fundamental domain of G_2. Both the\ncontinuous and discrete effective models show a rich phase structure with a\nferromagnetic, symmetric and several anti-ferromagnetic phases. The phase\ndiagram contains first and second order transition lines and tricritical\npoints. The modified mean field predictions compare very well with the results\nof our simulations.",
        "positive": "Topology and chiral symmetry breaking in QCD: We construct a model to study the impact of instantons on the low lying\neigenvalue spectrum of the Dirac operator. The model is by necessity,\napproximate, though it does incorporate the important symmetries of the\nunderlying field theory. The model also reproduces classical results in the\nappropriate limits. We find that generic instanton ensembles lead to an\naccumulation of eigenvalues around zero, and hence, break chiral symmetry. The\neigenvalue spectrum is divergent however, as the eigenvalue approaches zero.\nThis leads to a divergent chiral condensate in quenched QCD, and hence, shows\nthe theory to be pathological. In full QCD we find the novel result of a\ndivergent spectral density leading to chiral symmetry breaking, but, with a\nfinite condensate. This result holds for both $N_{f}=1$ and $N_{f}=2$. We also\ncompute correlation functions and find a massive $\\eta^{'}$ and $\\sigma$ in the\nchiral limit. Whilst the divergence follows a power law, the strength of the\ndivergence is inversely proportional to the instanton density. To investigate\nthe impact of the divergence further, we analyse instanton ensembles derived by\n\"cooling\" lattice gauge configurations. An important negative result is that\nthe chiral condensate is strongly dependent upon the number of cooling sweeps\nperformed. Whether the problem lies with cooling or with the identification of\ntopological objects is yet to be resolved."
    },
    {
        "anchor": "Matrix elements of the plaquette operator of Lattice Gauge Theory: We show that in the spin-network basis it is possible to compute the matrix\nelements of any given operator of the Hamiltonian formulation of Lattice Gauge\nTheory (LGT). We give the explicit calculation for the case of the plaquette\noperator.",
        "positive": "Dispersion relation and spectral range of Karsten-Wilczek and\n  Borici-Creutz fermions: We investigate some properties of Karsten-Wilczek and Borici-Creutz fermions,\nwhich are the best known varieties in the class of minimally doubled lattice\nfermion actions. Our focus is on the dispersion relation and the distribution\nof eigenvalues in the free-field theory. We consider the situation in two and\nfour space-time dimensions, and we discuss how properties vary as a function of\nthe Wilson-like lifting parameter $r$."
    },
    {
        "anchor": "K\\to\u03c0l \u03bdform factor with N_f=2+1 dynamical domain wall fermions: We present the latest results from the UKQCD/RBC collaborations for the\nK_{l3} form factor with 2+1 flavours of dynamical domain wall quarks.\nSimulations are performed on 16^3x32x16 and 24^3x64x16 lattices with three\nvalues of the light quark mass, allowing for an extrapolation to the chiral\nlimit. After interpolating to zero momentum transfer, we obtain the preliminary\nresult f_+^{K\\pi}(0)=0.9680(16), which is in excellent agreement with an\nearlier N_f=2 result.",
        "positive": "Fermion propagator at finite temperatures on extremely anisotropic\n  lattice: Fermion propagator is computed in a simple model on an extremely anisotropic\nlattice $\\xi\\gg1$. Fermion determinant is evaluated up to $\\xi^{-4}$ order.\nChiral condensate is estimated in mean field approximation."
    },
    {
        "anchor": "Some Considerations on Lattice Gauge Fixing: Some problems related to Gribov copies in lattice gauge-fixing and their\npossible solution are discussed.",
        "positive": "A confinement criterion for gauge theories with matter fields: A generalization of the Wilson loop area-law criterion is proposed, which is\napplicable to gauge theories with matter in the fundamental representation of\nthe gauge group. This new criterion, like the area law, is stronger than the\nstatement that asymptotic particle states are massive color singlets, which\nholds even for theories described by the Brout-Englert-Higgs mechanism."
    },
    {
        "anchor": "Charmonium Spectroscopy from Lattice QCD: I give a short review of the current status of lattice QCD calculations of\nthe spectrum of charmonium.",
        "positive": "Three-particle scattering amplitudes from lattice QCD: Lattice QCD already offers the possibility of extracting three-hadron\nscattering quantities from first principles. In the last few years, significant\nprogress has been achieved in developing and applying the finite-volume\nthree-body formalism. The formalism is now able to treat physically relevant\nsystems of three mesons, including those with resonances, as well as three-body\ndecays. In this talk, I will review the state of the art, and comment on recent\napplications to lattice QCD data for systems of three pions and kaons."
    },
    {
        "anchor": "Log-normal distribution for correlators in lattice QCD?: Many hadronic correlators used in spectroscopy calculations in lattice QCD\nsimulations appear to show a log-normal distribution at intermediate time\nseparations.",
        "positive": "Scattering phases for meson and baryon resonances on general\n  moving-frame lattices: A proposal by L\\\"uscher enables one to compute the scattering phases of\nelastic two-body systems from the energy levels of the lattice Hamiltonian in a\nfinite volume. In this work we generalize the formalism to S--, P-- and D--wave\nmeson and baryon resonances, and general total momenta. Employing nonvanishing\nmomenta has several advantages, among them making a wider range of energy\nlevels accessible on a single lattice volume and shifting the level crossing to\nsmaller values of $m_\\pi L$."
    },
    {
        "anchor": "First study of $N_f=2+1+1$ lattice QCD with physical domain-wall quarks: Using 10-16 units of Nvidia DGX-1, we have generated the first gauge ensemble\nfor $N_f=2+1+1$ lattice QCD with physical $(u/d, s, c)$ domain-wall quarks, on\nthe $ 64^4 $ lattice with lattice spacing $a \\sim 0.064 $ fm ($ L > 4 $ fm, and\n$ M_\\pi L > 3 $). The salient feature of this gauge ensemble is that the chiral\nsymmetry is preserved to a high precision and all topological sectors are\nsampled ergodically. In this paper, we present the first results of the\ntopological susceptibility and the ground-state hadron mass spectra.",
        "positive": "Confinement in QCD: The guiding lines of lattice investigations on colour confinement are\nreviewed, together with recent results."
    },
    {
        "anchor": "Blocked lattice monopoles in quenched SU(2) QCD and dual superconductor\n  model: We study the action of the lattice monopoles in quenched SU(2) QCD in the\nMaximal Abelian projection. We relate the lattice action of the monopole\ncurrents to the monopole degrees of freedom of the continuum dual\nsuperconductor model and obtain the value of the monopole condensate.",
        "positive": "Mean-Field Gauge Interactions in Five Dimensions II. The Orbifold: We study Gauge-Higgs Unification in five dimensions on the lattice by means\nof the mean-field expansion. We formulate it for the case of an SU(2) pure\ngauge theory and orbifold boundary conditions along the extra dimension, which\nexplicitly break the gauge symmetry to U(1) on the boundaries. Our main result\nis that the gauge boson mass computed from the static potential along\nfour-dimensional hyperplanes is nonzero implying spontaneous symmetry breaking.\nThis observation supports earlier data from Monte Carlo simulations [12]."
    },
    {
        "anchor": "The two-loop energy-momentum tensor within the gradient-flow formalism: The gradient-flow formulation of the energy-momentum tensor of QCD is\nextended to NNLO perturbation theory. This means that the Wilson coefficients\nwhich multiply the flowed operators in the corresponding expression for the\nregular energy-momentum tensor are calculated to this order. The result has\nbeen obtained by applying modern tools of regular perturbation theory, reducing\nthe occurring two-loop integrals, which also include flow-time integrations, to\na small set of master integrals which can be calculated analytically.",
        "positive": "Nonperturbative evaluation of the diffusion rate in field theory at high\n  temperatures: Kramer's approach to the rate of the thermally activated escape from a\nmetastable state is extended to field theory. Diffusion rate in the\n1+1-dimensional Sine-Gordon model as a function of temperature and friction\ncoefficient is evaluated numerically by solving the Langevin equation in real\ntime. A clear crossover from the semiclassical to the high temperature domain\nis observed. The temperature behaviour of the diffusion rate allows one to\ndetermine the kink mass which is found equal to the corresponding classical\nvalue. The Kramer's predictions for the dependence on viscosity are\nqualitatively valid in this multidimensional case. In the limit of vanishing\nfriction the diffusion rate is shown to coincide with the one obtained from the\ndirect measurements of the conventional classical real-time Green function at\nfinite temperature."
    },
    {
        "anchor": "Finite-volume corrections to charge radii: The finite-volume nature of lattice QCD entails a variety of effects that\nmust be handled in the process of performing chiral extrapolations. Since the\npion cloud that surrounds hadrons becomes distorted in a finite volume,\nhadronic observables must be corrected before one can compare with the\nexperimental values. The electric charge radius of the nucleon is of particular\ninterest when considering the implementation of finite-volume corrections. It\nis common practice in the literature to transform electric form factors from\nthe lattice into charge radii prior to analysis. However, there is a\nfundamental difficulty with using these charge radii in a finite-volume\nextrapolation. The subtleties are a consequence of the absence of a continuous\nderivative on the lattice. A procedure is outlined for handling such\nfinite-volume corrections, which must be applied directly to the electric form\nfactors themselves rather than to the charge radii.",
        "positive": "Study of compact U(1) flux tubes in 3+1 dimensions in lattice gauge\n  theory using GPU's: We utilize Polyakov loop correlations to study (3+1)D compact U(1) flux tubes\nand the static electron-positron potential in lattice gauge theory. By using\nfield operators it is possible in U(1) lattice gauge theory to probe directly\nthe electric and magnetic fields. In order to improve the signal-to-noise ratio\nin the confinement phase, we apply the L\\\"uscher-Weiss multilevel algorithm.\nOur code is written in CUDA, and we run it in NVIDIA FERMI generation GPU's, in\norder to achieve the necessary performance for our computations."
    },
    {
        "anchor": "Winding number expansion for the canonical approach to finite density\n  simulations: The canonical partition function approach was designed to avoid the overlap\nproblem that affects the lattice simulations of nuclear matter at high density.\nThe method employs the projections of the quark determinant on a fix quark\nnumber sector. When the quark number is large, the evaluation of the projected\ndeterminant becomes numerically unstable. In this paper a different evaluation\nmethod based on expanding the determinant in terms of loops winding around the\nlattice is studied. We show that this method is stable and significantly faster\nthan our original algorithm. This greatly expands the range of quark numbers\nthat we can simulate effectively.",
        "positive": "Failure of Mean Field Theory at Large N: We study strongly coupled lattice QCD with $N$ colors of staggered fermions\nin 3+1 dimensions. While mean field theory describes the low temperature\nbehavior of this theory at large $N$, it fails in the scaling region close to\nthe finite temperature second order chiral phase transition. The universal\ncritical region close to the phase transition belongs to the 3d XY universality\nclass even when $N$ becomes large. This is in contrast to Gross-Neveu models\nwhere the critical region shrinks as $N$ (the number of flavors) increases and\nmean field theory is expected to describe the phase transition exactly in the\nlimit of infinite $N$. Our work demonstrates that close to second order phase\ntransitions infrared fluctuations can sometimes be important even when $N$ is\nstrictly infinite."
    },
    {
        "anchor": "Complex Langevin analysis of 2D U(1) gauge theory on a torus with a\n  $\u03b8$ term: Monte Carlo simulation of gauge theories with a $\\theta$ term is known to be\nextremely difficult due to the sign problem. Recently there has been major\nprogress in solving this problem based on the idea of complexifying dynamical\nvariables. Here we consider the complex Langevin method (CLM), which is a\npromising approach for its low computational cost. The drawback of this method,\nhowever, is the existence of a condition that has to be met in order for the\nresults to be correct. As a first step, we apply the method to 2D U(1) gauge\ntheory on a torus with a $\\theta$ term, which can be solved analytically. We\nfind that a naive implementation of the method fails because of the topological\nnature of the $\\theta$ term. In order to circumvent this problem, we simulate\nthe same theory on a punctured torus, which is equivalent to the original model\nin the infinite volume limit for $ |\\theta| < \\pi$. Rather surprisingly, we\nfind that the CLM works and reproduces the exact results for a punctured torus\neven at large $\\theta$, where the link variables near the puncture become very\nfar from being unitary.",
        "positive": "An exact Polynomial Hybrid Monte Carlo algorithm for dynamical\n  Kogut-Susskind fermions: We present a polynomial Hybrid Monte Carlo (PHMC) algorithm as an exact\nsimulation algorithm with dynamical Kogut-Susskind fermions. The algorithm uses\na Hermitian polynomial approximation for the fractional power of the KS fermion\nmatrix. The systematic error from the polynomial approximation is removed by\nthe Kennedy-Kuti noisy Metropolis test so that the algorithm becomes exact at a\nfinite molecular dynamics step size. We performed numerical tests with\n$N_f$$=$2 case on several lattice sizes. We found that the PHMC algorithm works\non a moderately large lattice of $16^4$ at $\\beta$$=$5.7, $m$$=$0.02\n($m_{\\mathrm{PS}}/m_{\\mathrm{V}}$$\\sim$0.69) with a reasonable computational\ntime."
    },
    {
        "anchor": "The locality problem for two tastes of staggered fermions: We address the locality problem arising in simulations, which take the square\nroot of the staggered fermion determinant as a Boltzmann weight to reduce the\nnumber of dynamical quark tastes from four to two. We study analytically and\nnumerically the square root of the staggered fermion operator as a candidate to\ndefine a two taste theory from first principles. Although it has the correct\nweight, this operator is non-local in the continuum limit. Our work serves as a\nwarning that fundamental properties of field theories might be violated when\nemploying blindly the square root trick. The question, whether a local operator\nreproducing the square root of the staggered fermion determinant exists, is\nleft open.",
        "positive": "Taste-Changing in Staggered Quarks: We present results from a systematic perturbative investigation of\ntaste-changing in improved staggered quarks. We show one-loop taste-changing\ninteractions can be removed perturbatively by an effective four-quark term and\ncalculate the necessary coefficients."
    },
    {
        "anchor": "Adaptive gauge cooling for complex Langevin dynamics: In the case of nonabelian gauge theories with a complex weight, a controlled\nexploration of the complexified configuration space during a complex Langevin\nprocess requires the use of SL(N,C) gauge cooling, in order to minimize the\ndistance from SU(N). Here we show that adaptive gauge cooling can lead to an\nefficient implementation of this idea. First results for SU(3) Yang-Mills\ntheory in the presence of a nonzero theta-term are presented as well.",
        "positive": "<A^2> Condensate, Bianchi Identities and Chromomagnetic Fields\n  Degeneracy in SU(2) YM Theory: We consider the non-Abelian Bianchi identities in SU(2) pure Yang-Mills\ntheory in D=3,4 focusing on the possibility of their violation and the\nsignificance of the chromomagnetic fields degeneracy points. We show that the\nrecently proposed non-Abelian Stokes theorem allows to formulate the Bianchi\nidentities in terms of the physical fluxes and their relative color\norientations. Then the violation of Bianchi identities becomes a well defined\nconcept ultimately related to the degeneracy points. The locality and gauge\ninvariance of our approach allows to study the problem numerically. We present\nevidences that in D=4 the suppression of the Bianchi identities violation is\nlikely to destroy confinement while the removal of the degeneracy points drives\nthe theory to the topologically non-trivial sector. However, confronting the\nresults obtained in three and four dimensions we argue that it is the mass\ndimension two condensate <A^2_{min}> which probably explains our findings."
    },
    {
        "anchor": "Constraint on the Low Energy Constants of Wilson Chiral Perturbation\n  Theory: Wilson chiral perturbation theory (WChPT) is the effective field theory\ndescribing the long- distance properties of lattice QCD with Wilson or\ntwisted-mass fermions. We consider here WChPT for the theory with two light\nflavors of Wilson fermions or a single light twisted-mass fermion.\nDiscretization errors introduce three low energy constants (LECs) into\npartially quenched WChPT at O(a^2), conventionally called W'_6, W'_7 and W'_8 .\nThe phase structure of the theory at non-zero a depends on the sign of the\ncombination 2W'_6 + W'_8, while the spectrum of the lattice Hermitian\nWilson-Dirac operator depends on all three constants. It has been argued, based\non the positivity of partition functions of fixed topological charge, and on\nthe convergence of graded group integrals that arise in the epsilon-regime of\nChPT, that there is a constraint on the LECs arising from the underlying\nlattice theory. In particular, for W'_6 = W'_7 = 0, the constraint found is\nW'_8 \\le 0. Here we provide an alternative line of argument, based on mass\ninequalities for the underlying partially quenched theory. We find that W'_8\n\\le 0, irrespective of the values of W'_6 and W'_7. Our constraint implies that\n2W'_6 > |W'_8| if the phase diagram is to be described by the first-order\nscenario, as recent simulations suggest is the case for some choices of action.",
        "positive": "Symmetry Breaking, Duality and Fine-Tuning in Hierarchical Spin Models: We discuss three questions related to the critical behavior of hierarchical\nspin models: 1) the hyperscaling relations in the broken symmetry phase; 2) the\ncombined use of dual expansions to calculate the non-universal quantities; 3)\nthe fine-tuning issue in approximately supersymmetric models."
    },
    {
        "anchor": "Multigrid Monte Carlo Algorithms for SU(2) Lattice Gauge Theory: Two\n  versus Four Dimensions: We study a multigrid method for nonabelian lattice gauge theory, the time\nslice blocking, in two and four dimensions. For SU(2) gauge fields in two\ndimensions, critical slowing down is almost completely eliminated by this\nmethod. This result is in accordance with theoretical arguments based on the\nanalysis of the scale dependence of acceptance rates for nonlocal Metropolis\nupdates. The generalization of the time slice blocking to SU(2) in four\ndimensions is investigated analytically and by numerical simulations. Compared\nto two dimensions, the local disorder in the four dimensional gauge field leads\nto kinematical problems.",
        "positive": "Deconfinement and Hadron Resonance Gas for Heavy Quarks: I discuss the deconfinement transition in 2+1 flavor QCD in terms of Polyakov\nloops as well as the hadron resonance gas for hadrons containing static quarks\nand charm quarks."
    },
    {
        "anchor": "Phases of 2d massless QCD with qubit regularization: We investigate the possibility of reproducing the continuum physics of 2d\nSU(N) gauge theory coupled to a single flavor of massless Dirac fermions using\nqubit regularization. The continuum theory is described by N free fermions in\nthe ultraviolet (UV) and a coset Wess-Zumino-Witten (WZW) model in the infrared\n(IR). In this work, we explore how well these features can be reproduced using\nthe Kogut-Susskind Hamiltonian with a finite-dimensional link Hilbert space and\na generalized Hubbard coupling. Using strong coupling expansions, we show that\nour model exhibits a gapped dimer phase and another phase described by a\nspin-chain. Furthermore, for N=2, using tensor network methods, we show that\nthere is a second-order phase transition between these two phases. The critical\ntheory at the transition can be understood as an SU(2)_1 WZW model, using which\nwe determine the phase diagram of our model quantitatively. Using the\nconfinement properties of the model we argue how the UV physics of free\nfermions could also emerge, but may require further modifications to our model.",
        "positive": "U(1) flux tube profiles from Hamiltonian lattice gauge theory using a\n  random walk ground-state projector: We use a self-guided random walk to solve the ground-state problem of\nHamiltonian U(1) pure gauge theory in 2+1 dimensions in the string sector. By\nmaking use of the electric-field representation, we argue that the spatial\ndistribution of the electric field can be more easily measured than in ordinary\nMonte Carlo simulations."
    },
    {
        "anchor": "Sea quark effects in B Spectroscopy and Decay Constants: We present comprehensive results for the spectrum and decay constants of\nhadrons containing a single b quark. The heavy quark is simulated using an\n$O(1/M)$ NRQCD action and the light quark using the $O(a)$ tadpole-improved\nclover action on gauge configurations containing two degenerate flavours of sea\nquarks at $\\beta^{n_f=2}=5.6$ provided by the HEMCGC collaboration. We present\ndetailed results for the lower lying $S$ and $P$ wave $B$ meson states and the\n$\\Lambda_b$ baryon. We find broad agreement with experiment. In addition, we\npresent results for the pseudoscalar and, for the first time, the vector decay\nconstants fully consistent to $O(\\alpha/M): f_B =\n186(5)(stat)(19)(pert)(9)(disc)(13)(NRQCD)(+50)(a^{-1})MeV, f_B^* = 181(6)\n(stat)(18)(pert)(9)(disc)(13)(NRQCD)(+55)(a^{-1})MeV$ and $f_{B_s}/f_B =\n1.14(2)(stat)(-2)(\\kappa_s)$. We present an investigation of sea quark effects\nin the $B$ spectrum and decay constants. We compare our results with those from\nsimilar quenched simulations at $\\beta^{n_f=0}=6.0$. For the spectrum, the\nquenched results reproduce the experimental spectrum well and there is no\nsignificant difference between the quenched and $n_f=2$ results. For the decay\nconstants, our results suggest that sea quark effects may be large. We find\nthat $f_B$ increases by approximately 25% between $n_f=0$ and $n_f=2$.",
        "positive": "On fits to correlated and auto-correlated data: Observables in particle physics and specifically in lattice QCD calculations\nare often extracted from fits. Standard $\\chi^2$ tests require a reliable\ndetermination of the covariance matrix and its inverse from correlated and\nauto-correlated data, a challenging task often leading to close-to-singular\nestimates. These motivate modifications of the definition of $\\chi^2$ such as\nuncorrelated fits. We show how the goodness-of-fit measured by their p-value\ncan still be estimated robustly for a broad class of such fits."
    },
    {
        "anchor": "Effective SU(2) Polyakov Loop Theories with Heavy Quarks on the Lattice: We compare SU(2) Polyakov loop models with different effective actions with\ndata from full two-color QCD simulations around and above the critical\ntemperature. We then apply the effective theories at finite temperature and\ndensity to extract quantities like Polyakov loop correlators, effective\nPolyakov loop potentials and baryon density.",
        "positive": "Landau Gauge Fixing on GPUs: In this paper we present and explore the performance of Landau gauge fixing\nin GPUs using CUDA. We consider the steepest descent algorithm with Fourier\nacceleration, and compare the GPU performance with a parallel CPU\nimplementation. Using $32^4$ lattice volumes, we find that the computational\npower of a single Tesla C2070 GPU is equivalent to approximately 256 CPU cores."
    },
    {
        "anchor": "The sign problem in the $\u03b5$-regime of QCD: QCD in the $\\epsilon$-regime at nonzero baryon chemical potential $\\mu$ is\nreviewed. The focus is on aspects of the sign problem which are relevant for\nlattice QCD. It is discussed how spontaneous chiral symmetry breaking and the\nsign problem are related through the spectrum of the Dirac operator. The\nstrength of the sign problem is linked to the quark mass and the chemical\npotential. Specific implications for lattice QCD are discussed.",
        "positive": "The fate of axial U(1) in 2+1 flavor QCD towards the chiral limit: The region of the Columbia plot with two light quark flavors is not yet\nconclusively understood. Non-perturbative effects, e.g. the magnitude of the\nanomalous U(1) axial symmetry breaking, decides on the nature of the phase\ntransition in this region. We report on our study of this region of the\nColumbia plot using lattice techniques. We use gauge field ensembles generated\nwithin the Highly Improved Staggered Quark discretization scheme, with the\nstrange quark mass fixed at its physical value and the light quark mass varied\nsuch that $m_l=m_s/27$ and $m_s/40$, where $m_l=m_s/27$ corresponds to the\nphysical light quark mass. We study the eigenvalue spectrum of QCD using the\noverlap Dirac operator on these gauge field ensembles at finite temperature\naround the chiral transition temperature $T_c$, as the light quark masses\napproach the chiral limit, and infer about the fate of the anomalous $U_A(1)$\nsymmetry breaking."
    },
    {
        "anchor": "Mass spectroscopy using Borici-Creutz fermion on 2D lattice: Minimally doubled fermion proposed by Creutz and Borici is a promising chiral\nfermion formulation on lattice. In this work, we present excited state mass\nspectroscopy for the meson bound states in Gross-Neveu model using\nBorici-Creutz fermion. We also evaluate the effective fermion mass as a\nfunction of coupling constant which shows a chiral phase transition at strong\ncoupling. The lowest lying meson in 2-dimensional QED is also obtained using\nBorici-Creutz fermion.",
        "positive": "Instantons or Monopoles? Dyons: Non-abelian gauge theories can be cast into abelian gauge theories with\nmonopoles. We ask what becomes of the instantons after abelian projection.\nInstantons are found to consist of closed dyon loops. It is shown that the\nelectric charge of the dyons is quantized. The implication of this result for\nthe dynamics of the Yang-Mills vacuum is briefly discussed."
    },
    {
        "anchor": "Simulating linear covariant gauges on the lattice: a new approach: We discuss a new lattice implementation of the linear covariant gauge,\nrecently introduced in [1]. In particular, we present details of the numerical\nprocedure for fixing the gauge. We also report on preliminary results for the\ntransverse and longitudinal gluon propagators for the SU(2) gauge group in four\nspace-time dimensions.",
        "positive": "Lattice study of light scalar tetraquarks with I=0,2,1/2,3/2: are sigma\n  and kappa tetraquarks?: We investigate whether the lightest scalar mesons sigma and kappa have a\nlarge tetraquark component, as is strongly supported by many phenomenological\nstudies. A search for possible light tetraquark states with J^PC=0^++ and I=0,\n2, 1/2, 3/2 on the lattice is presented. We perform the two-flavor dynamical\nsimulation with Chirally Improved quarks and the quenched simulation with\noverlap quarks, finding qualitative agreement between both results. The\nspectrum is determined using the generalized eigenvalue method with a number of\ntetraquark interpolators at the source and the sink, and we omit the\ndisconnected contractions. The time-dependence of the eigenvalues at finite\ntemporal extent of the lattice is explored also analytically. In all the\nchannels, we unavoidably find lowest scattering states pi(k)pi(-k) or\nK(k)pi(-k) with back-to-back momentum k=0, 2*pi/L,... However, we find an\nadditional light state in the I=0 and I=1/2 channels, which may be interpreted\nas the observed resonances sigma and kappa with a sizable tetraquark component.\nIn the exotic repulsive channels I=2 and I=3/2, where no resonance is observed,\nwe find no light state in addition to the scattering states."
    },
    {
        "anchor": "Lattice QCD at finite temperature: some aspects related to chiral\n  symmetry: Out of the many exciting results obtained with the lattice approach to QCD\nunder extreme conditions, I discuss a few selected items related to chiral\nsymmetry: the chiral condensate as an approximate order parameter, meson\nscreening masses, and masses of baryons and mesons, including D(s) mesons, when\napproaching the crossover from the hadronic side.",
        "positive": "Renormalization constants for Wilson fermion lattice QCD with four\n  dynamical flavours: We report on an ongoing non-perturbative computation of RI-MOM scheme\nrenormalization constants for the lattice action with four dynamical flavours\ncurrently in use by ETMC. For this goal dedicated simulations with four\ndegenerate sea quark flavours are performed at several values of the standard\nand twisted quark mass parameters. We discuss a method for removing possible\nO(a) artifacts at all momenta and extrapolating renormalization constant\nestimators to the chiral limit. We give preliminary results at one lattice\nspacing."
    },
    {
        "anchor": "Matrix elements and baryon spectroscopy from unquenched lattice QCD with\n  improved staggered quarks: We look for the effect of open decay channels on the masses of baryons in\nunquenched lattice QCD. We apply variational smearing using fuzzed basis states\nto a staggered nucleon operator. The signal for the s_bar s current in the\nnucleon is studied. The lattice calculations are done using improved staggered\nfermions.",
        "positive": "Gonihedric 3D Ising Actions: We investigate a generalized Ising action containing nearest neighbour, next\nto nearest neighbour and plaquette terms that has been suggested as a potential\nstring worldsheet discretization on cubic lattices by Savvidy and Wegner. We\nuse both mean field techniques and Monte-Carlo simulations to sketch out the\nphase diagram.\n  The Gonihedric (Savvidy-Wegner) model has a symmetry that allows any plane of\nspins to be flipped with zero energy cost, which gives a highly degenerate\nvacuum state. We choose boundary conditions in the simulations that eliminate\nthis degeneracy and allow the definition of a simple ferromagnetic order\nparameter. This in turn allows us to extract the magnetic critical exponents of\nthe system."
    },
    {
        "anchor": "Gauge-equivariant neural networks as preconditioners in lattice QCD: We demonstrate that a state-of-the art multi-grid preconditioner can be\nlearned efficiently by gauge-equivariant neural networks. We show that the\nmodels require minimal re-training on different gauge configurations of the\nsame gauge ensemble and to a large extent remain efficient under modest\nmodifications of ensemble parameters. We also demonstrate that important\nparadigms such as communication avoidance are straightforward to implement in\nthis framework.",
        "positive": "Vacuum Structure of the Ichimatsu-Decomposed Lattice Models: We proposed an `Ichimatsu'-decomposed lattice gauge theory with fermionic\nsymmetries. The vacuum structures of the gauge sector with two coupling\nconstants ($\\beta_p,\\beta_c$) are investigated for 3-dimensional Z$_2$ and\n4-dimensional SU(2) cases using mean-field approximation and numerical\nsimulation. We found two phases on the ($\\beta_p,\\beta_c$) phase diagram for\n3-dim. Z$_2$ case, while the diagram is a single phase for the latter."
    },
    {
        "anchor": "HISQ 2+1+1 light quark hadronic vacuum polarization at the physical\n  point: We report on the computation of the light quark vacuum polarization with\n2+1+1 flavors of H ISQ fermions at the physical point and its contribution to\nthe muon anomalous magnetic moment. Three ensembles, generated by the MILC\ncollaboration, are used to take the continuum limit. We compare our result with\nrecent ones in the literature.",
        "positive": "Perturbative renormalization group, exact results and high temperature\n  series to order 21 for the N-vector spin models on the square lattice: High temperature expansions for the susceptibility and the second correlation\nmoment of the classical N-vector model (also known as the O(N) symmetric\nHeisenberg classical spin model or the as the lattice O(N) nonlinear sigma\nmodel) on the square lattice are extended from order beta^{14} to beta^{21} for\narbitrary N. For the second field derivative of the susceptibility the series\nexpansion is extended from order beta^{14} to beta^{17}. For -2 < N < 2, a\nnumerical analysis of the series is performed in order to compare the critical\nexponents gamma(N), nu(N) and Delta(N) to exact (though nonrigorous) formulas\nand to compute the \"dimensionless four point coupling constant\" g_r(N). For N >\n2, we present a study of the analiticity properties of chi, xi etc. in the\ncomplex beta-plane and describe a method to estimate the parameters which\ncharacterize their low-temperature behaviors. We compare our series estimates\nto the predictions of the perturbative renormalization group theory, to exact\n(but nonrigorous or conjectured) formulas and to the results of the 1/N\nexpansion, always finding a good agreement."
    },
    {
        "anchor": "Supersymmetric Yang-Mills theory: a step towards the continuum: The spectrum of supersymmetric Yang-Mills theory presented so far shows an\nunexpected gap between the bosonic and fermionic masses. This finding was in\ncontradiction with the basic requirements of supersymmetry. In this work we\nwill present new results indicating that the mass gap is reduced at a smaller\nlattice spacing. Hence lattice artifacts are the most likely explanation for\nit. These new results have been obtained at a larger beta value and on a larger\nlattice.",
        "positive": "Hyperon-Nucleon Interactions and the Composition of Dense Nuclear Matter\n  from Quantum Chromodynamics: The low-energy neutron-Sigma^- interactions determine, in part, the role of\nthe strange quark in dense matter, such as that found in astrophysical\nenvironments. The scattering phase shifts for this system are obtained from a\nnumerical evaluation of the QCD path integral using the technique of Lattice\nQCD. Our calculations, performed at a pion mass of m_pi ~ 389 MeV in two large\nlattice volumes, and at one lattice spacing, are extrapolated to the physical\npion mass using effective field theory. The interactions determined from QCD\nare consistent with those extracted from hyperon-nucleon experimental data\nwithin uncertainties, and strengthen theoretical arguments that the strange\nquark is a crucial component of dense nuclear matter."
    },
    {
        "anchor": "Computation of the relation between the bare lattice coupling and the\n  MSbar coupling in SU(N) gauge theories to two loops: The perturbation expansion of the MSbar coupling in the SU(N) gauge theory in\npowers of the bare lattice coupling is extended to two-loop order. A discussion\nof our results has already been published elsewhere. We here describe the\ncalculation in some detail. It relies on the background field technique and a\nrecently introduced coordinate space method to evaluate lattice Feynman\nintegrals.",
        "positive": "On the phase structure of lattice QCD with twisted-mass Wilson fermions\n  at non-zero temperature: In this talk we give an overview of the 3D phase diagram of two-flavour\nnon-zero temperature lattice QCD with twisted-mass Wilson fermions and a\ntree-level Symanzik-improved gauge action. We present a first feasibility study\nat maximal twist and, for the quenched case, we demonstrate automatic\nO(a)-improvement to work."
    },
    {
        "anchor": "Low energy constants from the chirally improved Dirac operator D_CI: The leading order low energy parameters like the pion decay constant or the\nquark condensate are well-known from \"classical\" low energy theorems and\nexperiments. It is a challenge, however, to find these parameters based\nexclusively on an ab-initio QCD calculation. We discuss results of a quenched\nlattice calculation of low energy constants using the chirally improved Dirac\noperator. Several lattice sizes at different lattice spacings are studied,\nusing pseudoscalar and axial vector correlators. We find consistent results for\nf_\\pi = 96(2) MeV, f_K = 105(2) MeV, \\Sigma = -(286(4) MeV)^3, the average\nlight quark mass m = 4.1(2.4) MeV and m_s = 101(8) MeV.",
        "positive": "Restoration of supersymmetry in two-dimensional SYM with sixteen\n  supercharges on the lattice: We perform lattice simulations of two-dimensional supersymmetric Yang-Mills\ntheory with sixteen supercharges with a lattice action which has two exact\nsupercharges (Sugino lattice action). According to the gauge/gravity duality,\nthe theory at finite temperature is expected to be well described by the\ncorresponding black 1-branes, at low temperature in the large N limit. We aim\nto confirm the duality conjecture by comparing the lattice results with the\ntheoretical predictions obtained in the gravity side. In this article, at the\nbeginning of this study, we examine the supersymmetric Ward-Takahashi identity\nto test whether the lattice action reproduces the correct continuum theory.\nNumerical results of the SUSY WTI strongly suggest us that any cut-off effects,\nwhich break supersymmetry, disappear in the continuum limit. In addition, we\nstudy the issue of degenerate vacua and find that the admissiblilty condition\nor any other constraints of the link fields which guarantee the unique vacuum\nare not always needed."
    },
    {
        "anchor": "Collins-Soper kernel from lattice QCD at the physical pion mass: This work presents a determination of the quark Collins-Soper kernel, which\nrelates transverse-momentum-dependent parton distributions (TMDs) at different\nrapidity scales, using lattice Quantum Chromodynamics (QCD). This is the first\nlattice QCD calculation of the kernel at quark masses corresponding to a\nclose-to-physical value of the pion mass, with next-to-next-leading logarithmic\nmatching to TMDs from the corresponding lattice-calculable distributions, and\nincludes a complete analysis of systematic uncertainties arising from operator\nmixing. The kernel is extracted at transverse momentum scales\n$240\\,\\text{MeV}\\lesssim q_{T}\\lesssim 1.6\\,\\text{GeV}$ with a precision\nsufficient to begin to discriminate between different phenomenological models\nin the non-perturbative region.",
        "positive": "Anisotropic Membranes: We describe the statistical behavior of anisotropic crystalline membranes. In\nparticular we give the phase diagram and critical exponents for phantom\nmembranes and discuss the generalization to self-avoiding membranes."
    },
    {
        "anchor": "Pion decay constant in quenched QCD with Kogut-Susskind quarks: We present a non-perturbative calculation for the pion decay constant with\nquenched Kogut-Susskind quarks. Numerical simulations are carried out at $\\beta\n= 6.0$ and 6.2 with various operators extending over all flavors. The\nrenormalization correction is applied for each flavor by computing\nnon-perturbative renormalization constants, and it is compared with a\nperturbative calculation. We also study the behavior of $f_\\pi$ in the\ncontinuum limits for both non-perturbative and perturbative calculations. The\nresults in the continuum limit is also discussed.",
        "positive": "Nonperturbatively Renormalized Nucleon Gluon Momentum Fraction in the\n  Continuum Limit of $N_f=2+1+1$ Lattice QCD: We present the nonperturbatively renormalized nucleon gluon momentum fraction\nusing ensembles with $2+1+1$ flavors of highly improved staggered quarks\n(HISQ), generated by MILC Collaboration. The calculation is done using clover\nfermions for the valence action with three pion masses, $220$, $310$ and $690$\nMeV and three lattice spacings, 0.09, 0.12, and 0.15 fm. The renormalization is\ndone using RI/MOM nonperturbative renormalization and using\ncluster-decomposition error reduction (CDER) to enhance the signal-to-noise\nratio of the renormalization constant. We find the CDER technique is\nparticularly important to improve the signal at the finer lattice ensembles\nwhere the lattice volume is larger. We extrapolate the gluon momentum fraction\nto the continuum-physical limit and obtain $\\langle x \\rangle_g =\n0.492(52)_\\text{stat.+NPR}(49)_\\text{mixing}$ in the $\\bar{\\text{MS}}$ scheme\nat 2 GeV, where first error includes the statistical error and uncertainties in\nnonperturbative renormalization, while the latter systematic accounts for\nignoring quark mixing. Our gluon momentum fraction is consistent with other\nrecent lattice-QCD results at physical pion mass."
    },
    {
        "anchor": "Sign problem and subsets in one-dimensional QCD: We present a subset method that solves the sign problem for QCD at nonzero\nquark chemical potential in 0+1 dimensions. The subsets of gauge configurations\nare constructed using the center symmetry of the SU(3) group. These subsets\ncompletely solve the sign problem for up to five flavors. For a larger number\nof flavors the sign problem slowly reappears, and we propose an extension of\nthe subsets that also solves the sign problem for these cases. The subset\nmethod allows for numerical simulations of the model at nonzero chemical\npotential. We also present some preliminary results on subsets for QCD in two,\nthree, and four dimensions.",
        "positive": "QCD thermodynamics from an imaginary mu_B: results on the four flavor\n  lattice model: We study four flavor QCD at nonzero temperature and density by analytic\ncontinuation from an imaginary chemical potential. The explored region is T =\n0.95 T_c < T < 3.5 T_c, and the baryochemical potentials range from 0 to\napprox. 500 MeV. Observables include the number density, the order parameter\nfor chiral symmetry, and the pressure, which is calculated via an integral\nmethod at fixed temperature and quark mass. The simulations are carried out on\na 16^3 X 4 lattice, and the mass dependence of the results is estimated by\nexploiting the Maxwell relations. In the hadronic region we confirm that the\nresults are consistent with a simple resonance hadron gas model, and we\nestimate the critical density by combining the results for the number density\nwith those for the critical line. In the hot phase, above the endpoint of the\nRoberge-Weiss transition T_E approx 1.1 T_c the results are consistent with a\nfree lattice model with a fixed effective number of flavor slightly different\nfrom four. We confirm that confinement and chiral symmetry are coincident by a\nfurther analysis of the critical line, and we discuss the interrelation between\nthermodynamics and critical behavior. We comment on the strength and weakness\nof the method, and propose further developments."
    },
    {
        "anchor": "Adaptive Multigrid Algorithm for Lattice QCD: We present a new multigrid solver that is suitable for the Dirac operator in\nthe presence of disordered gauge fields. The key behind the success of the\nalgorithm is an adaptive projection onto the coarse grids that preserves the\nnear null space. The resulting algorithm has weak dependence on the gauge\ncoupling and exhibits very little critical slowing down in the chiral limit.\nResults are presented for the Wilson Dirac operator of the 2d U(1) Schwinger\nmodel.",
        "positive": "The nucleon magnetic moment in the epsilon-regime of HBChPT: The nucleon magnetic moment is calculated in the epsilon-regime of Heavy\nBaryon Chiral Perturbation Theory to order epsilon^3, using the method of\ncollective variables to integrate nonperturbative pion zero modes.\nContributions containing multiple sources of zero modes enter, allowing for\ncharge-carrying zero mode pion fields that connect the sources. The result of\nthis calculation will allow for lattice QCD calculations involving nucleons to\nsystematically extract the leading low energy coefficients of Heavy Baryon\nChiral Perturbation Theory with electromagnetic interactions."
    },
    {
        "anchor": "Scattering phase shift determinations from a two-scalar field theory: A field theory involving two interacting scalar fields, previously studied by\nRummukainen and Gottlieb, is revisited. Our study is not restricted to the\nlimit of large quartic couplings, and a Symanzik-improved action is used so\nthat continuum dispersion relations work well. The Metropolis method, combined\nwith a local microcanonical updating algorithm, is employed in our Monte Carlo\ncalculations. Isotropic lattices ranging from $16^3 \\times 48$ to $53^3 \\times\n48$ are used, and scattering phase shifts are determined using a L\\\"uscher\nanalysis with multiple partial waves.",
        "positive": "Monopole action and monopole condensation in SU(3) lattice QCD: Effective monopole actions for various extended monopoles are derived from\nvacuum configurations after abelian projection in the maximally abelian gauge\nin $T=0$ and $T\\ne 0$ $SU(3)$ lattice QCD. The actions obtained appear to be\nindependent of the lattice volume adopted. At zero temperature, monopole\ncondensation is seen to occur from energy-entropy balance in the strong\ncoupling region.\n  Larger $\\beta$ is included in the monopole condensed phase as more extended\nmonopoles are considered. The scaling seen in the $SU(2)$ case is not yet\nobserved. The renormalization flow diagram suggests the existence of an\ninfrared fixed point. A hysteresis behavior is seen around the critical\ntemperature in the case of the $T\\ne 0$ action."
    },
    {
        "anchor": "A novel analysis method for excited states in lattice QCD - the nucleon\n  case: We employ a novel method to analyze Euclidean correlation functions entering\nthe calculation of hadron energies in lattice QCD. The method is based on the\nsampling of all possible solutions allowed by the spectral decomposition of the\nhadron correlators. We demonstrate the applicability of the method by studying\nthe nucleon excited states in the positive and negative parity channels over a\npion mass range of about 400~MeV to 150~MeV. The results are compared to the\nstandard variational approach routinely used to study excited states within\nlattice QCD. The main advantage of our new approach is its ability to\nunambiguously determine all excited states for which the Euclidean time\ncorrelation function is sensitive on.",
        "positive": "Chiral extrapolation beyond the power-counting regime: Chiral effective field theory can provide valuable insight into the chiral\nphysics of hadrons when used in conjunction with non-perturbative schemes such\nas lattice QCD. In this discourse, the attention is focused on extrapolating\nthe mass of the rho meson to the physical pion mass in quenched QCD (QQCD).\nWith the absence of a known experimental value, this serves to demonstrate the\nability of the extrapolation scheme to make predictions without prior bias. By\nusing extended effective field theory developed previously, an extrapolation is\nperformed using quenched lattice QCD data that extends outside the chiral\npower-counting regime (PCR). The method involves an analysis of the\nrenormalization flow curves of the low energy coefficients in a finite-range\nregularized effective field theory. The analysis identifies an optimal\nregulator, which is embedded in the lattice QCD data themselves. This optimal\nregulator is the regulator value at which the renormalization of the low energy\ncoefficients is approximately independent of the range of quark masses\nconsidered. By using recent precision, quenched lattice results, the\nextrapolation is tested directly by truncating the analysis to a set of points\nabove 380 MeV, while being blinded of the results probing deeply into the\nchiral regime. The result is a successful extrapolation to the chiral regime."
    },
    {
        "anchor": "Evaluating Sea Quark Contributions to Flavour-Singlet Operators in\n  Lattice QCD: In a full QCD lattice study with $N_f = 2$ Wilson fermions, we seek to\noptimize the signals for the disconnected contributions to the matrix element\nof flavour-singlet operators between nucleon states, which are indicative for\nsea quark effects. We demonstrate, in form of a fluctuation analysis to the\nnoisy estimator technique, that -- in order to achieve a tolerable signal to\nnoise-ratio in full QCD -- it is advantageous to work with a $Z_2$-noise source\nrather than to rely only on gauge invariance to cancel non-gauge-invariant\nbackground. In the case of the $\\pi$N $\\sigma$-term, we find that 10\n$Z_2$-noise sources suffice on our sample ( about 150 independent QCD\nconfigurations at $\\beta = 5.6$ on $16^3\\times32$ with $\\kappa_{sea} = 0.157$,\nequivalent to $M_{\\pi}/M_{\\rho} = 0.76(1)$), to achieve decent signals and\nadequate fluctuations, rather than 300 such sources as recently used in\nquenched simulations.",
        "positive": "Random membrane model for lattice gluodynamics: odel for studying coupling dependence on lattice spacing a in gluodynamics is\nsuggested. The model predicts $g-> g_{0}>0 with a->0. Free energy density in\nthe model does not depend on temperature."
    },
    {
        "anchor": "A comparative study of two lattice approaches to two-body systems: We present a method to extract the spectrum of two-particle systems on the\nlattice from wave functions computed in lattice simulations. The energies of\nthe Hamiltonian eigenstates are extracted from the eigenvalues of a matrix,\nsimilar to a potential, constrained by the wave functions. This method is\ncompared with the traditional variational method in the isospin 2 $\\pi\\pi$\nsystem.",
        "positive": "Scaling topological charge in the CP^3 spin model: The CP^3 spin model is simulated at large correlation lengths in two\ndimensions. An overrelaxation algorithm is employed which yields reduced\ncritical slowing down with dynamical exponents z around unity. We compare our\nresults with recent multigrid data on the massgap m and the spin susceptibility\nand confirm the absence of asymptotic scaling. As a new result we find scaling\nfor the universal topological susceptibility with values extrapolating to chi_t\n/ m^2 = 0.156(2) in the continuum limit."
    },
    {
        "anchor": "Lyapunov exponents in Minkowskian U(1) gauge theory: U(1) gauge fields are decomposed into a monopole and photon part across the\nphase transition from the confinement to the Coulomb phase. We analyze the\nleading Lyapunov exponents of such gauge field configurations on the lattice\nwhich are initialized by quantum Monte Carlo simulations. We observe that the\nmonopole field carries the same Lyapunov exponent as the original U(1) field.\nEvidence is found that monopole fields stay chaotic in the continuum whereas\nthe photon fields are regular.",
        "positive": "A New visita to the SU(N) gauge field confinement: Based on our exact effective spin model, the zero temperature $SU(N)$ gauge\nfield confinement has been studied by the deconfinement-confinement phase\ntransition order parameter, i.e. the Wilson line, rather than the quark\nantiquark potential. The procedure would allow one to study the confinement in\nthe true continuum limit. For the $(1+1)$ $SU(2)$ gauge field, the confinement\nand a linear zero temperature Polyakov quark antiquark potential were shown. It\nis also shown, for the first time, that the Polyakov and Wilson potentials are\nidentical."
    },
    {
        "anchor": "Generating SU(Nc) pure gauge lattice QCD configurations on GPUs with\n  CUDA: The starting point of any lattice QCD computation is the generation of a\nMarkov chain of gauge field configurations. Due to the large number of lattice\nlinks and due to the matrix multiplications, generating SU(Nc) lattice QCD\nconfigurations is a highly demanding computational task, requiring advanced\ncomputer parallel architectures such as clusters of several Central Processing\nUnits (CPUs) or Graphics Processing Units (GPUs). In this paper we present and\nexplore the performance of CUDA codes for NVIDIA GPUs to generate SU(Nc)\nlattice QCD pure gauge configurations. Our implementation in one GPU uses CUDA\nand in multiple GPUs uses OpenMP and CUDA. We present optimized CUDA codes\nSU(2), SU(3) and SU(4). We also show a generic SU(Nc) code for Nc$\\,\\geq 4$ and\ncompare it with the optimized version of SU(4). Our codes are publicly\navailable for free use by the lattice QCD community.",
        "positive": "Heavy-light mesons in 2+1 flavor lattice QCD: Heavy-light meson system is investigated using the relativistic heavy quark\naction on the 2+1 dynamical flavor PACS-CS configurations at the lattice\nspacing $a^{-1}=2.2$ GeV and the spatial extent L=3 fm. Dynamical up-down and\nstrange quark masses as well as the valence charm quark mass are set around\ntheir physical values. We measure the charm-$ud$ and charm-strange meson masses\nand decay constants. Our results are consistent with the experimental values\nexcept the hyperfine splitting of the charm-strange meson. We also estimate the\nCKM matrix elements in the second row."
    },
    {
        "anchor": "First results for $B_K$ on the ultrafine ($a=0.045$ fm) ensemble: We present preliminary results for $B_K$ from the MILC ultrafine lattices,\nbased on a partial ensemble of 305 configurations. We use HYP-smeared improved\nstaggered valence quarks. The analysis is done using fitting forms based on\nboth SU(2) and SU(3) staggered chiral perturbation thery. For the SU(2)\nanalysis, we find that the result using the NLO fit function is consistent with\nthat from a partial NNLO fit. For the SU(3) analysis, where we have to use\npartially constrained fits due to the number of fit parameters, we find that\nour two preferred fits (\"N-BB1\" and \"N-BB2\") are also consistent, both with\neach other and with the results of the SU(2) fits. These results are used in\ncompanion proceedings to improve the control over the continuum extrapolation.",
        "positive": "Nucleon matrix elements using the variational method in lattice QCD: The extraction of hadron matrix elements in lattice QCD using the standard\ntwo- and three-point correlator functions demands careful attention to\nsystematic uncertainties. One of the most commonly studied sources of\nsystematic error is contamination from excited states. We apply the variational\nmethod to calculate the axial vector current $g_{A}$, the scalar current\n$g_{S}$ and the quark momentum fraction $\\left<x\\right>$ of the nucleon and we\ncompare the results to the more commonly used summation and two-exponential fit\nmethods. The results demonstrate that the variational approach offers a more\nefficient and robust method for the determination of nucleon matrix elements."
    },
    {
        "anchor": "Monte Carlo simulation of $\u03c6^4_2$ and $O(N)\u03c6^4_3$ theories: We report lattice simulations of $\\phi^4_2$ and $O(N)\\,\\phi^4$ models,\nperformed by means of a Monte Carlo method based on the all-order strong\ncoupling expansion (worm algorithm). The investigation of the non-perturbative\nfeatures of the $\\phi^4$ continuum limit in two dimensions lead us to the\nresult $g/\\mu^2 = 11.15 \\pm 0.06_{stat} \\pm 0.03_{syst}$ for the critical\ncoupling. Furthermore we present preliminary results for the three-dimensional\n$O(2)\\phi^4\\,$ model using the worm algorithm with the extention to\n$O(N)\\phi^4\\,$ in $D$ dimensions.",
        "positive": "Pairs of chiral quarks on the lattice from staggered fermions: A new formulation of chiral fermions on the lattice is presented. It is a\nversion of overlap fermions, but built from the computationally efficient\nstaggered fermions rather than the previously used Wilson fermions. The\nconstruction reduces the four quark flavors described by the staggered fermion\nto two quark flavors; this pair can be taken as the up and down quarks in\nLattice QCD. The exact flavored chiral symmetry of the staggered fermion gets\nconverted into an unflavored Ginsparg-Wilson chiral symmetry of the new overlap\nfermion, which also has pairs of exact chiral zero-modes satisfying the Index\nTheorem. Stability under radiative corrections is checked. A domain wall\nformulation giving a truncation of this overlap construction is also outlined."
    },
    {
        "anchor": "Series expansion of the quark determinant in the number of\n  quark-antiquark pairs: We propose a formulation of the QCD partition function which leads to a\nseries expansion of the quark determinant in any given baryonic sector. The\nr-th term gives the gauge-invariant contribution of the valence quarks plus r\nquark-antiquark pairs. This expansion can be used to investigate any baryonic\nsector, starting from the nucleon up to high baryonic densities.",
        "positive": "Further Study of BRST-Symmetry Breaking on the Lattice: We evaluate the so-called Bose-ghost propagator Q(p^2) for SU(2) gauge theory\nin minimal Landau gauge, considering lattice volumes up to 120^4 and physical\nlattice extents up to 13.5 f. In particular, we investigate discretization\neffects, as well as the infinite-volume and continuum limits. We recall that a\nnonzero value for this quantity provides direct evidence of BRST-symmetry\nbreaking, related to the restriction of the functional measure to the first\nGribov region. Our results show that the prediction (from cluster\ndecomposition) for Q(p^2) in terms of gluon and ghost propagators is better\nsatisfied as the continuum limit is approached."
    },
    {
        "anchor": "Nucleon form factors with Nf=2 dynamical twisted mass fermions: We present results on the electromagnetic and axial nucleon form factors\nusing two degenerate flavors of twisted mass fermions on lattices of spatial\nsize 2.1 fm and 2.7 fm and a lattice spacing of about 0.09 fm. We consider pion\nmasses in the range of 260-470 MeV. We chirally extrapolate results on the\nnucleon axial ch arge, the isovector Dirac and Pauli root mean squared radii\nand magnetic moment to the physical point and co mpare to experiment.",
        "positive": "Renormalisation of gauge theories on general anisotropic lattices and\n  high-energy scattering in QCD: We study the renormalisation of $SU(N_c)$ gauge theories on general\nanisotropic lattices, to one-loop order in perturbation theory, employing the\nbackground field method. The results are then applied in the context of two\ndifferent approaches to hadronic high-energy scattering. In the context of the\nEuclidean nonperturbative approach to soft high-energy scattering based on\nWilson loops, we refine the nonperturbative justification of the analytic\ncontinuation relations of the relevant Wilson-loop correlators, required to\nobtain physical results. In the context of longitudinally-rescaled actions, we\nstudy the consequences of one-loop corrections on the relation between the\n$SU(N_c)$ gauge theory and its effective description in terms of\ntwo-dimensional principal chiral models."
    },
    {
        "anchor": "Large-N volume reduction of lattice QCD with adjoint Wilson fermions at\n  weak-coupling: We study the large-N volume reduction of QCD with adjoint quarks regularized\non the lattice. Specifically, we use Wilson fermions, and while our\nd-dimensional lattice has (d-1) infinite dimensions, the remaining direction is\nreduced to a point. We perform a weak-coupling one-loop calculation of the free\nenergy as a function of the holonomy in the reduced direction, and map the\nregimes in the bare lattice parameter space where the holonomy averages to zero\nand a Z_N-center symmetric configuration is the ground state. For d=4 and\nN_f=1/2,1 and 2 Dirac flavors we see that the center symmetry is intact in a\ngenerous regime of the phase diagram that includes the chiral point. Thus we\nsee that large-N volume independence of lattice QCD with adjoint Wilson quarks\nworks at weak coupling. Interestingly, we find that this is true even if the\nquark mass is quite large, and this opens a path to study the volume reduced\nlarge-N pure gauge theory. Finally, we analyze in detail the UV sensitivity of\nthe one-loop potential and show that treating the reduced theory as a\n(d-1)-dimensional effective field theory requires the introduction of certain\nrelevant operators that are a subset of those suggested by Unsal and Yaffe to\nstabilize the center symmetry. This means that different regularizations of the\nvolume-reduced theory can be compared only if one includes these terms in the\naction.",
        "positive": "Recent Lattice QCD Results from the UKQCD Collaboration: The lattice technique of studying the strong interaction of matter is used to\nobtain predictions of the hadronic spectrum. These simulations were performed\nby the UKQCD collaboration using full (unquenched) QCD. Details of the results,\na comparison with quenched data, and novel methods of extracting spectral\nproperties are described."
    },
    {
        "anchor": "Quenched QCD near the chiral limit: A numerical study of quenched QCD for light quarks is presented using O(a)\nimproved fermions. Particular attention is paid to the possible existence and\ndetermination of quenched chiral logarithms. A `safe' region to use for chiral\nextrapolations appears to be at and above the strange quark mass.",
        "positive": "Duals of U(N) LGT with staggered fermions: Various approaches to construction of dual formulations of non-abelian\nlattice gauge theories are reviewed. In the case of U(N) LGT we use a theory of\nthe Weingarten functions to construct a dual formulation. In particular, the\ndual representations are constructed 1) for pure gauge models in all\ndimensions, 2) in the strong coupling limit for the models with arbitrary\nnumber of flavours and 3) for two-dimensional U(N) QCD with staggered fermions.\nApplications related to the finite temperature/density QCD are discussed."
    },
    {
        "anchor": "Automated Methods in Chiral Perturbation Theory on the Lattice: We present a method to automatically derive the Feynman rules for mesonic\nchiral perturbation theory with a lattice regulator. The Feynman rules can be\noutput both in a human-readable format and in a form suitable for an automated\nnumerical evaluation of lattice Feynman diagrams. The automated method\nsignificantly simplifies working with improved or extended actions. Some\napplications to the study of finite-volume effects will be presented.",
        "positive": "Hamiltonian effective field theory study of the $\\mathbf{N^*(1535)}$\n  resonance in lattice QCD: Drawing on experimental data for baryon resonances, Hamiltonian effective\nfield theory (HEFT) is used to predict the positions of the finite-volume\nenergy levels to be observed in lattice QCD simulations of the lowest-lying\n$J^P=1/2^-$ nucleon excitation. In the initial analysis, the phenomenological\nparameters of the Hamiltonian model are constrained by experiment and the\nfinite-volume eigenstate energies are a prediction of the model. The agreement\nbetween HEFT predictions and lattice QCD results obtained on volumes with\nspatial lengths of 2 and 3 fm is excellent. These lattice results also admit a\nmore conventional analysis where the low-energy coefficients are constrained by\nlattice QCD results, enabling a determination of resonance properties from\nlattice QCD itself. Finally, the role and importance of various components of\nthe Hamiltonian model are examined."
    },
    {
        "anchor": "Flavor singlet phenomena in lattice QCD: Flavor singlet combinations of quark operators ${\\cal{O}}_S^{\\Gamma} =\n\\bar{u}\\Gamma u + \\bar{d}\\Gamma d + \\bar{s}\\Gamma s$ contribute to many\nimportant physical observables in the low energy region of QCD. Experimentally\none finds the values of some of these observables to be in sharp contrast to\nthe naive (perturbative) theoretical expectations. This indicates that non\nperturbative vacuum properties might play a major role in the comprehension of\nthese phenomena. An example of such a vacuum contribution is the axial anomaly,\nwhich appears in the divergence of the flavor singlet axial current and which\nis connected to the topological properties of QCD. From a field theoretical\npoint of view flavor singlet matrix elements differ from non singlet amplitudes\nin the occurrence of so called disconnected insertions. These are correlations\nof hadron propagators with quark-antiquark loops or correlations between\nquark-antiquark loops, which are mediated by vacuum fluctuations. According to\ntheir respective flavor composition, the disconnected insertions cancel largely\nin non singlet processes, but add in flavor singlet amplitudes. The lattice\napproach provides an ideal tool to study flavor singlet phenomena. Being a\nfirst principle method it should be capable to uncover non perturbative vacuum\ncontributions and to yield, on the long run, reliable results for the size of\nsuch contributions in QCD. The present article reviews the status of flavor\nsinglet matrix element calculations in lattice QCD with respect to methods,\nresults and reliability. Special emphasis is paid to the discussion of state of\nthe art calculations of the pion nucleon sigma term $\\sigma_{\\pi N}$, the\nflavor singlet axial coupling of the proton $G_A^1$, and the $\\eta'$ mass.",
        "positive": "The Anisotropic Wilson Gauge Action: Anisotropic lattices, with a temporal lattice spacing smaller than the\nspatial one, allow precision Monte Carlo calculations of problems that are\ndifficult to study otherwise: heavy quarks, glueballs, hybrids, and high\ntemperature thermodynamics, for example. We here perform the first step\nrequired for such studies with the (quenched) Wilson gauge action, namely, the\ndetermination of the renormalized anisotropy $\\xi$ as a function of the bare\nanisotropy $\\xi_0$ and the coupling. By, essentially, comparing the\nfinite-volume heavy quark potential where the quarks are separated along a\nspatial direction with that where they are separated along the time direction,\nwe determine the relation between $\\xi$ and $\\xi_0$ to a fraction of 1% for\nweak and to 1% for strong coupling. We present a simple parameterization of\nthis relation for $1\\leq \\xi \\leq 6$ and $5.5 \\leq \\beta \\leq \\infty$, which\nincorporates the known one-loop result and reproduces our non-perturbative\ndeterminations within errors. Besides solving the problem of how to choose the\nbare anisotropies if one wants to take the continuum limit at fixed\nrenormalized anisotropy, this parameterization also yields accurate estimates\nof the derivative $\\partial\\xi_0/\\partial\\xi$ needed in thermodynamic studies."
    },
    {
        "anchor": "Lattice simulations of QCD with $\u03bc_B\\neq0$ versus phase quenched QCD: Previously published lattice results for QCD at $\\mu_B\\neq0$ are compared to\nanalytic predictions for phase quenched QCD. We observe that the strength of\nthe sign problem in QCD is linked directly to the position of the phase\ntransition line for pion condensation in phase quenched QCD and that the number\nof terms needed in the Taylor expansion approach depends on the strength of the\nsign problem. Together this emphasizes the physical importance of the sign\nproblem and helps to clarify the range over which the Taylor expansion approach\nis practically applicable. Finally, we observe that the positions of the\nendpoint of the first order chiral phase transition in the QCD phase diagram\nfound in two successive computations by Fodor and Katz are both close to the\nposition of the phase transition line for pion condensation in phase quenched\nQCD.",
        "positive": "Inverse Renormalization Group in Quantum Field Theory: We propose inverse renormalization group transformations within the context\nof quantum field theory that produce the appropriate critical fixed point\nstructure, give rise to inverse flows in parameter space, and evade the\ncritical slowing down effect in calculations pertinent to criticality. Given\nconfigurations of the two-dimensional $\\phi^{4}$ scalar field theory on sizes\nas small as $V=8^{2}$, we apply the inverse transformations to produce rescaled\nsystems of size up to $V'=512^{2}$ which we utilize to extract two critical\nexponents. We conclude by discussing how the approach is generally applicable\nto any method that successfully produces configurations from a statistical\nensemble and how it can give novel insights into the structure of the\nrenormalization group."
    },
    {
        "anchor": "Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: isospin-1 $KK$\n  scattering length: We present results for the interaction of two kaons at maximal isospin. The\ncalculation is based on $N_f=2+1+1$ flavour gauge configurations generated by\nthe European Twisted Mass Collaboration with pion masses ranging from about\n$230$ to $450\\,\\textrm{MeV}$ at three values of the lattice spacing. The\nelastic scattering length $a_0^{I=1}$ is calculated at several values of the\nbare strange and light quark masses. We find $M_K a_0 =\n-0.385(16)_{\\textrm{stat}} (^{+0}_{-12})_{m_s}(^{+0}_{-5})_{Z_P}(4)_{r_f}$ as\nthe result of a combined extrapolation to the continuum and to the physical\npoint, where the first error is statistical, and the three following are\nsystematical. This translates to $a_0 =\n-0.154(6)_{\\textrm{stat}}(^{+0}_{-5})_{m_s}\n(^{+0}_{-2})_{Z_P}(2)_{r_f}\\,\\textrm{fm}$.",
        "positive": "A first look at Landau-gauge propagators in G2 Yang-Mills theory: G_2 Yang--Mills theory is an interesting laboratory to investigate\nnon-perturbative effects. On one hand, no conventional quark confinement via a\nlinearly rising potential is present. On the other hand, its thermodynamic\nproperties are similar to ordinary SU(N) Yang--Mills theory. Finally, it has\nbeen conjectured that gluons are removed from the physical spectrum in the same\nway as in SU(N) Yang--Mills theory. The last claim will be explored by\ndetermining the Landau-gauge ghost and gluon propagators, as well as the\nFaddeev--Popov operator eigenspectrum, in G_2 lattice gauge theory in two and\nthree dimensions. The results are found to agree qualitatively with the SU(2)\nand SU(3) case. Therefore, the conjecture that Yang--Mills theories with\ndifferent gauge groups are qualitatively similar on the level of their Landau\ngauge Green's functions is supported."
    },
    {
        "anchor": "Novel Quantum Monte Carlo Algorithms for Fermions: Recent research shows that the partition function for a class of models\ninvolving fermions can be written as a statistical mechanics of clusters with\npositive definite weights. This new representation of the model allows one to\nconstruct novel algorithms. We illustrate this through models consisting of\nfermions with and without spin. A Hubbard type model with both attractive and\nrepulsive interactions becomes tractable using the new approach. Precision\nresults in the two dimensional attractive model confirm a superfluid phase\ntransition in the Kosterlitz-Thouless universality class.",
        "positive": "Chiral Properties of Quenched and Full QCD: We extend a technique for the chiral extrapolation of hadron masses\ncalculated with dynamical fermions to those generated by quenched simulations.\nThe method ensures the correct leading and next-to-leading non-analytic\nbehaviour for either QCD or quenched QCD in the chiral limit, as well as the\ncorrect large quark mass behaviour. We find that the primary difference between\nquenched and dynamical baryon masses can be described by the meson loops which\ngive rise to the different leading and next-to-leading non-analytic behaviour."
    },
    {
        "anchor": "Memory efficient finite volume schemes with twisted boundary conditions: In this paper we explore a finite volume renormalization scheme that combines\nthree main ingredients: a coupling based on the gradient flow, the use of\ntwisted boundary conditions and a particular asymmetric geometry, that for\n$SU(N)$ gauge theories consists on a hypercubic box of size $l^2 \\times\n(Nl)^2$, a choice motivated by the study of volume independence in large $N$\ngauge theories. We argue that this scheme has several advantages that make it\nparticularly suited for precision determinations of the strong coupling, among\nthem translational invariance, an analytic expansion in the coupling and a\nreduced memory footprint with respect to standard simulations on symmetric\nlattices, allowing for a more efficient use of current GPU clusters. We test\nthis scheme numerically with a determination of the $\\Lambda$ parameter in the\n$SU(3)$ pure gauge theory. We show that the use of an asymmetric geometry has\nno significant impact in the size of scaling violations, obtaining a value\n$\\Lambda_{\\overline{MS}} \\sqrt{8 t_0} =0.603(17)$ in good agreement with the\nexisting literature. The role of topology freezing, that is relevant for the\ndetermination of the coupling in this particular scheme and for large $N$\napplications, is discussed in detail.",
        "positive": "News from bottomonium spectral functions in thermal QCD: New results on bottomonium at nonzero temperature are presented, using the\nFASTSUM Generation 2L ensembles. Preliminary results for spectral function\nreconstruction using Kernel Ridge Regression, a machine learning technique, are\nshown as well and compared to results from the Maximum Entropy Method."
    },
    {
        "anchor": "SU(2) Low-Energy Constants from Mixed-Action Lattice QCD: An analysis of the pion mass and pion decay constant is performed using\nmixed-action Lattice QCD calculations with domain-wall valence quarks on\nensembles of rooted, staggered n_f = 2+1 MILC configurations. Calculations were\nperformed at two lattice spacings of b~0.125 fm and b~0.09 fm, at two strange\nquark masses, multiple light quark masses, and a number of lattice volumes. The\nratios of light quark to strange quark masses are in the range 0.1 <= m_l / m_s\n<= 0.6, while pion masses are in the range 235 < m_\\pi < 680 MeV. A two-flavor\nchiral perturbation theory analysis of the Lattice QCD calculations constrains\nthe Gasser-Leutwyler coefficients bar{l}_3 and bar{l}_4 to be bar{l}_3 =\n4.04(40)(+73-55) and bar{l}_4 = 4.30(51)(+84-60). All systematic effects in the\ncalculations are explored, including those from the finite lattice space-time\nvolume, the finite lattice spacing, and the finite fifth dimension in the\ndomain-wall quark action. A consistency is demonstrated between a chiral\nperturbation theory analysis at fixed lattice spacing combined with a leading\norder continuum extrapolation, and the mixed-action chiral perturbation theory\nanalysis which explicitly includes the leading order discretization effects.\nChiral corrections to the pion decay constant are found to give f_\\pi / f =\n1.062(26)(+42-40) where f is the decay constant in the chiral limit. The most\nrecent scale setting by the MILC Collaboration yields a postdiction of f_\\pi =\n128.2(3.6)(+4.4-6.0)(+1.2-3.3) MeV at the physical pion mass.",
        "positive": "More on Lattice BRST Invariance: In the gauge-fixing approach to (chiral) lattice gauge theories, the action\nin the U(1) case implicitly contains a free ghost term, in accordance with the\ncontinuum abelian theory. On the lattice there is no BRST symmetry and, without\nfermions, the partition function is strictly positive. Recently, Neuberger\npointed out in hep-lat/9801029 that a different choice of the ghost term would\nlead to a BRST-invariant lattice model, which is ill-defined nonperturbatively.\nWe show that such a lattice model is inconsistent already in perturbation\ntheory, and clearly different from the gauge-fixing approach."
    },
    {
        "anchor": "Update on SU(2) gauge theory with NF = 2 fundamental flavours: We present a non perturbative study of SU(2) gauge theory with two\nfundamental Dirac flavours. This theory provides a minimal template which is\nideal for a wide class of Standard Model extensions featuring novel strong\ndynamics, such as a minimal realization of composite Higgs models. We present\nan update on the status of the meson spectrum and decay constants based on\nincreased statistics on our existing ensembles and the inclusion of new\nensembles with lighter pion masses, resulting in a more reliable chiral\nextrapolation.",
        "positive": "Chiral perturbation theory for gradient flow observables: We construct the next-to-leading order chiral lagrangian for scalar and\npseudo-scalar densities defined using the gradient flow. We calculate the\nchiral condensate and the pion decay constant to this order from operators at\npositive flow time, and confirm results obtained earlier in the chiral limit.\nWe also calculate the quark mass dependence of the scales $t_0$ and $w_0$\ndefined from the scalar gluon density and find that nonanalytic terms in the\nquark mass only enter at next-to-next-to-leading order."
    },
    {
        "anchor": "Lattice study of ChPT beyond QCD: We describe initial results by the Lattice Strong Dynamics (LSD)\ncollaboration of a study into the variation of chiral properties of chiral\nproperties of SU(3) Yang-Mills gauge theory as the number of massless flavors\nchanges from $N_f = 2$ to $N_f = 6$, with a focus on the use of chiral\nperturbation theory.",
        "positive": "How well do domain wall fermions realize chiral symmetry?: In the domain wall fermion formulation, chiral symmetry breaking in full QCD\nis expected to fall exponentially with the length of the extra dimension. We\nmeasure the chiral symmetry breaking due to a finite extra dimension in two\nways, which can be affected differently by finite volume and explicit fermion\nmass. For quenched QCD the two methods generally agree, except for the largest\nextent of the extra dimension, which makes the limit uncertain. We have less\ndata for full QCD, but see exponential suppression for the method where we have\ndata."
    },
    {
        "anchor": "Electromagnetic Structure of Spin-$\\frac12$ Doubly Charmed Baryons in\n  Lattice QCD: We compute the electromagnetic properties of spin-$\\frac12$ doubly charmed\nbaryons on 2+1 flavor lattices that have a pion mass of $\\sim$ 156 MeV. The\nTsukuba action is employed for the charm quark in addition to the standard\nisotropic Clover action to quantify the $\\mathcal{O}(m_q a)$ effects. We\ncalculate the electric and magnetic Sachs form factors and extract the magnetic\nmoments and electric and magnetic charge radii. We also investigate the\nindividual quark sector contributions to the charge radii and the magnetic\nmoments. The results provide vital information to understand the size and shape\nof the doubly charmed baryons. We find that the two heavy charm quarks drive\nthe charge radii and the magnetic moments to smaller values than that of light\nbaryons. The central values of the observables that are obtained using the\nrelativistic action for the charm quark are $5$ to $10\\%$ larger than those\nobtained using the Clover action. Utilizing the available lattice data, we\nreexamine the quark mass dependence of the observables.",
        "positive": "Heavy quark momentum broadening in a non-Abelian plasma away from\n  thermal equilibrium: We perform classical-statistical real-time lattice simulations to compute\nreal-time spectral functions and momentum broadening of quarks in the presence\nof strongly populated non-Abelian gauge fields. Based on a novel methodology to\nextract the momentum broadening for relativistic quarks, we find that the\nmomentum distribution of quarks exhibit interesting non-perturbative features\nas a function of time due to correlated momentum kicks it receives from the\nmedium, eventually going over to a diffusive regime. We extract the momentum\ndiffusion coefficient for a mass range describing charm and bottom quarks and\nfind sizeable discrepancies from the heavy quark limit."
    },
    {
        "anchor": "Breaking of the adjoint string in 2+1 dimensions: The roughly linear rise of the potential found between adjoint sources in\nSU(N) in lattice simulations is expected to saturate into a state of two\n`gluelumps' due to gluonic screening. We examine this in SU(2) in 2+1\ndimensions. Crossover between string-like and broken states is clearly seen by\nthe mixing-matrix technique, using different operators to probe the two states;\nthe breaking behaviour is rather abrupt. Furthermore, we are able to show that\nboth types of operator have a finite overlap with both states; in the case of\nthe Wilson loops the overlap with the broken string is, as predicted, very\nsmall.",
        "positive": "Light quarks with twisted mass fermions: We investigate Wilson twisted mass fermions in the quenched approximation\nusing different definitions of the critical bare quark mass m_c to realize\nmaximal twist and, correspondingly, automatic O(a) improvement for physical\nobservables. A particular definition of m_c is given by extrapolating the value\nof m_c obtained from the PCAC relation at non-vanishing bare twisted quark mass\nmu to mu=0. Employing this improved definition of the critical mass the Wilson\ntwisted mass formulation provides the possibility to perform reliable\nsimulations down to very small quark masses with correspondingly small pion\nmasses of m_pi \\simeq 250 MeV, while keeping the cutoff effects of O(a^2) under\ncontrol."
    },
    {
        "anchor": "Magnetic condensation and confinement in lattice gauge theory: We investigate Abelian monopoles and Abelian vortices condensation in finite\ntemperature SU(2) and SU(3) pure lattice gauge theories.",
        "positive": "Chiral extrapolations of baryon masses for unquenched three-flavor\n  lattice simulations: We have analyzed the chiral expansion of the baryon masses to second order in\nthe quark masses, including strong isospin violation. The calculations are\nperformed in Lorentz-invariant baryon chiral perturbation theory. Chiral\nextrapolation functions for three-flavor unquenched lattice simulations are\nderived. The matching to the two-flavor case and the sigma terms are also\nconsidered."
    },
    {
        "anchor": "Controlling complex Langevin dynamics at finite density: At nonzero chemical potential the numerical sign problem in lattice field\ntheory limits the use of standard algorithms based on importance sampling.\nComplex Langevin dynamics provides a possible solution, but it has to be\napplied with care. In this review, we first summarise our current understanding\nof the approach, combining analytical and numerical insight. In the second part\nwe study SL(N,C) gauge cooling, which was introduced recently as a tool to\ncontrol complex Langevin dynamics in nonabelian gauge theories. We present new\nresults in Polyakov chain models and in QCD with heavy quarks and compare\nvarious adaptive cooling implementations.",
        "positive": "Ising description of the transition region in SU(3) gauge theory at\n  finite temperature: We attempt the numerical construction of an effective action in three\ndimensions for Ising spins which represent the Wilson lines in the\nfour-dimensional SU(3) gauge theory at finite temperature. For each\nconfiguration of the gauge theory, each spin is determined by averaging the\nWilson lines over a small neighborhood and then projecting the average to +/-1\naccording to whether the neighborhood is ordered or disordered. The effective\nIsing action, determined via the lattice Schwinger-Dyson equations, contains\neven (two-spin) and odd (one- and three-spin) terms with short range. We find\nthat the truncation to Ising degrees of freedom produces an effective action\nwhich is discontinuous across the gauge theory's phase transition. This\ndiscontinuity may disappear if the effective action is made more elaborate."
    },
    {
        "anchor": "Moving NRQCD and B to K* gamma: The formulation of NRQCD discretized in a reference frame boosted relative to\nthe B rest frame will enable calculation of B form factors over a larger range\nof momentum transfer. We have initiated a program to calculate form factors\ndescribing the rare decay B to K* gamma. We discuss the strategy and challenges\nof the project. As a first step in the numerical calculations, we present first\nresults for bottomonium quantities using the O(Lambda_{QCD}^2/m^2, v_{NR}^4)\nmoving NRQCD action.",
        "positive": "Investigating a mixed action approach for \u03b7 and \u03b7' mesons in\n  Nf=2+1+1 lattice QCD: We present results for a test of a mixed action approach with\nOsterwalder-Seiler valence quarks on a Wilson twisted mass sea for the example\n{\\eta}, {\\eta}' mesons. Flavour singlet pseudoscalar mesons obtain significant\ncontributions from disconnected diagrams and are, therefore, expected to be\nparticularly sensitive to mixed regularisations. We employ different procedures\nfor matching valence and sea quark actions and show that the results agree in\nthe continuum limit."
    },
    {
        "anchor": "Glueballs and Hybrid Mesons: We discuss states in the meson spectrum which have explicit gluonic\ncomponents. Glueballs (with no valence quarks) and hybrid mesons (with valence\nquarks) are both reviewed. We present in some detail lattice simulation\nresults. ( to appear in proceedings of QCD-20 years, Aachen Workshop)",
        "positive": "Short distance repulsion in 3 nucleon forces from perturbative QCD: We investigate the short distance behavior of 3 nucleon forces (3NF) defined\nthrough Nambu--Bethe--Salpeter wave functions, using the operator product\nexpansion(OPE) and calculating anomalous dimensions of 9--quark operators in\nperturbative QCD. As is the case of NN forces previously considered, we show\nthat 3NF have repulsions at short distance at 1--loop, which becomes exact in\nthe short distance limit thanks to the asymptotic freedom of QCD. Moreover\nthese behaviors are universal in the sense that they do not depend on the\nenergy of the NBS wave function for 3 nucleons."
    },
    {
        "anchor": "The overlap Dirac operator as a continued fraction: We use a continued fraction expansion of the sign-function in order to obtain\na five dimensional formulation of the overlap lattice Dirac operator. Within\nthis formulation the inverse of the overlap operator can be calculated by a\nsingle Krylov space method and nested conjugate gradient procedures are\navoided. We point out that the five dimensional linear system can be made well\nconditioned using equivalence transformations on the continued fractions.",
        "positive": "Parton Distribution Functions with Twisted Mass Fermions: We present a first Wilson twisted mass fermion calculation of the matrix\nelement between pion states of the twist-2 operator, which is related to the\nthe lowest moment < x > of the valence quark parton distribution function in a\npion. Using Wilson twisted mass fermions in the quenched approximation we\ndemonstrate that < x > can be computed at small pseudoscalar meson masses down\nto values of order 250 MeV. We investigate the scaling behaviour of this\nphysically important quantity by applying two definitions of the critical mass\nand observe a scaling compatible with the expected O(a^2) behaviour in both\ncases. A combined continuum extrapolation allows to obtain reliable results for\n< x > at very small pseudoscalar meson masses, which previously could not be\nexplored by lattice QCD simulations."
    },
    {
        "anchor": "Contents of Lattice 98 Proceedings: We give here a compilation of papers presented at Lattice 98 (XVI Intl.\nSymposium on Lattice Field Theory, Boulder, Colorado, USA, 13-18 July 1998).\nThe contents are in html form with clickable links to the papers that exist on\nthe hep-lat archives. We hope that this will make it easier to access the\npresentations at the conference. Comments on, and corrections to, this\ncompilation should be sent to degrand@aurinko.colorado.edu. Version 3: some\nmore additions to the list.",
        "positive": "Recent results for the proton spin decomposition from lattice QCD: The exact decomposition of the proton spin has been a much debated topic, on\nthe experimental as well as the theoretical side. In this talk we would like to\nreport on recent non-perturbative results and ongoing efforts to explore the\nproton spin from lattice QCD. We present results for the relevant generalized\nform factors from gauge field ensembles that feature a physical value of the\npion mass. These generalized form factors can be used to determine the total\nspin and angular momentum carried by the quarks. In addition we present first\nresults for our ongoing effort to compute the angular momentum of the gluons in\nthe proton."
    },
    {
        "anchor": "A Model for QCD at High Density and Large Quark Mass: We study the high density region of QCD within an effective model obtained in\nthe frame of the hopping parameter expansion and choosing Polyakov type of\nloops as the main dynamical variables representing the fermionic matter. To get\na first idea of the phase structure, the model is analyzed in strong coupling\nexpansion and using a mean field approximation. In numerical simulations, the\nmodel still shows the so-called sign problem, a difficulty peculiar to non-zero\nchemical potential, but it permits the development of algorithms which ensure a\ngood overlap of the Monte Carlo ensemble with the true one. We review the main\nfeatures of the model and present calculations concerning the dependence of\nvarious observables on the chemical potential and on the temperature, in\nparticular of the charge density and the diquark susceptibility, which may be\nused to characterize the various phases expected at high baryonic density. We\nobtain in this way information about the phase structure of the model and the\ncorresponding phase transitions and cross over regions, which can be considered\nas hints for the behaviour of non-zero density QCD.",
        "positive": "Towards continuum limit of screening lengths with chiral Fermions: We investigate mesonic screening correlators at T=2T_c using the overlap\nFermions in the quenched approximation, where T_c is the QCD phase transition\ntemperature. Using lattices with temporal extent up to 8, we found that both\npseudoscalar and vector correlators exhibit a nice $cosh$ behaviour, leading to\na plateau behaviour in the local screening masses as a function of distance.\nThe rho and pi masses so determined show very little variation with the lattice\nspacing a. This augurs well for the use of chiral Fermions, and further\nsuggests the small deviations of these masses from the ideal gas values are\ngenuine effects of interactions."
    },
    {
        "anchor": "Lattice constraints on the thermal photon rate: We estimate the photon production rate from an SU(3) plasma at temperatures\nof about 1.1Tc and 1.3Tc. Lattice results for the vector current correlator at\nspatial momenta k ~ (2-6)T are extrapolated to the continuum limit and analyzed\nwith the help of a polynomial interpolation for the corresponding spectral\nfunction, which vanishes at zero frequency and matches to high-precision\nperturbative results at large invariant masses. For small invariant masses the\ninterpolation is compared with the NLO weak-coupling result, hydrodynamics, and\na holographic model. At vanishing invariant mass we extract the photon rate\nwhich for k \\gsim 3T is found to be close to the NLO weak-coupling prediction.\nFor k \\lsim 2T uncertainties remain large but the photon rate is likely to fall\nbelow the NLO prediction, in accordance with the onset of a strongly\ninteracting behaviour characteristic of the hydrodynamic regime.",
        "positive": "Phase transition of four-dimensional Ising model with tensor network\n  scheme: We investigate the phase transition of the four-dimensional Ising model with\ntwo types of tensor network scheme, one is the higher-order tensor\nrenormalization group and the other is the anisotropic tensor renormalization\ngroup. The results for the internal energy and magnetization obtained by the\nformer algorithm with the impure tensor method, enlarging the lattice volume up\nto $1024^4$, are consistent with the weak first-order phase transition. For the\nlater algorithm, our implementation successfully reduces the execution time\nthanks to the parallel computation and the results provided by ATRG seems\ncomparable to those with HOTRG."
    },
    {
        "anchor": "Simulating Wilson fermions without critical slowing down: We present a simulation algorithm for Wilson fermions based on the exact\nhopping expansion of the fermion action. The algorithm essentially eliminates\ncritical slowing down by sampling the fermionic two-point correlation function\nand it allows simulations directly in the massless limit. As illustrative\nexamples, the algorithm is applied to the Gross-Neveu and the Schwinger model,\nthe latter in the strong coupling limit.",
        "positive": "Investigation of the scalar spectrum in SU(3) with eight degenerate\n  flavors: The Lattice Strong Dynamics collaboration is investigating the properties of\na SU(3) gauge theory with $N_f = 8$ light fermions on the lattice. We measure\nthe masses of the lightest pseudoscalar, scalar and vector states using\nsimulations with the nHYP staggered-fermion action on large volumes and at\nsmall fermion masses, reaching $M_{\\rho}/M_{\\pi} \\approx 2.2$. The axial-vector\nmeson and the nucleon are also studied for the same range of fermion masses.\nOne of the interesting features of this theory is the dynamical presence of a\nlight flavor-singlet scalar state with $0^{++}$ quantum numbers that is lighter\nthan the vector resonance and has a mass consistent with the one of the\npseudoscalar state for the whole fermion mass range explored. We comment on the\nexistence of such state emerging from our lattice simulations and on the\nchallenges of its analysis. Moreover we highlight the difficulties in pursuing\nsimulations in the chiral regime of this theory using large volumes."
    },
    {
        "anchor": "$K^{+}\\to\u03c0^{+}\u03c0^{0}$ Decay Amplitude with the Wilson Quark Action in\n  Quenched Lattice QCD: We present a calculation for the $K^+\\to\\pi^+ \\pi^0 $ decay amplitude using a\nquenched simulation of lattice QCD with the Wilson quark action at\n$\\beta=6/g^2=6.1$. The decay amplitude is extracted from the ratio, the\n$K\\to\\pi\\pi$ three-point function divided by either $K$ and $\\pi$ meson\ntwo-point functions or $K$ meson two-point function and I=2 $\\pi\\pi$ four-point\nfunction; the two different methods yield consistent results. Finite size\neffects are examined with calculations made on $24^3\\times 64$ and $32^3\\times\n64$ lattices, and are shown that they are explained by one-loop effects of\nchiral perturbation theory. The lattice amplitude is converted to the continuum\nvalue by employing a one-loop calculation of chiral perturbation theory,\nyielding a value in agreement with experiment if extrapolated to the chiral\nlimit. We also report on the $K$ meson $B$ parameter $B_K$ obtained from the\n$K^+\\to\\pi^+\\pi^0$ amplitude using chiral perturbation theory.",
        "positive": "Factorization of Fermion Doubles on the Lattice: We address the problem of the fermion species doubling on the Lattice. Our\nstrategy is to factorize the fermion doubles from the action. The mass term of\nthe Dirac-Wilson action is changed. In this case the extra roots which appear\nin the action of free fermions in the moment representation are independent of\nthe mass and can be factorized from the fermion propagator. However the gauge\ncouplings suffer from the pathological ghost poles which are common to\nnon-local actions. This action can be used to find a solution of the Ginsparg\nWilson relation, which is cured from the non-local pathology. Finally we\ncompare this factorized action with solutions of The Ginsparg Wilson relation.\nWe find that the present is equivalent to the Zenkin action, and that is not\nquite as local as the Neuberger action."
    },
    {
        "anchor": "$K_L-K_S$ mass difference from lattice QCD: We report on the first complete calculation of the $K_L-K_S$ mass difference,\n$\\Delta M_K$, using lattice QCD. The calculation is performed on a 2+1 flavor,\ndomain wall fermion ensemble with a 330MeV pion mass and a 575 MeV kaon mass.\nWe use a quenched charm quark with a 949 MeV mass to implement\nGlashow-Iliopoulos-Maiani cancellation. For these heavier-than-physical\nparticle masses, we obtain $\\Delta M_K =3.19(41)(96)\\times 10^{-12}$ MeV, quite\nsimilar to the experimental value. Here the first error is statistical and the\nsecond is an estimate of the systematic discretization error. An interesting\naspect of this calculation is the importance of the disconnected diagrams, a\ndramatic failure of the OZI rule.",
        "positive": "SU(3) breaking effects in hyperon beta decay from lattice QCD: We present results of an exploratory study of flavor SU(3) breaking effects\nin hyperon beta decays using domain wall fermions. From phenomenological point\nof view, the significance of this subject is twofold: (1) to extract the\nelement $V_{us}$ of the Cabibbo-Kabayashi-Maskawa mixing matrix from the\n$\\Delta S=1$ decay process, and (2) to provide vital information to analysis of\nthe strange quark fraction of the proton spin with the polarized deep inelastic\nscattering data. In this study, we explore the $\\Xi^0 \\to \\Sigma^+$ beta decay,\nwhich is highly sensitive to the SU(3) breaking since this decay corresponds to\nthe direct analogue of neutron beta decay under an exchange between the down\nquark and the strange quark. We expose the SU(3) breaking effect on\n$g_A/g_V=g_1(0)/f_1(0)$ up to the first order in breaking. The second-class\nform factors $g_2$ and $f_3$, of which non-zero values are the direct signals\nof the SU(3) breaking effect, are also measured. Finally, we estimate $f_1(0)$\nup to the second-order correction and then evaluate $|V_{us}|$ combined with\nthe KTeV experiment."
    },
    {
        "anchor": "Progress Towards an ab initio, Standard Model Calculation of Direct\n  CP-Violation in K-decays: We discuss the RBC & UKQCD collaboration's progress towards a\nfirst-principles calculation of direct CP-violation in the Standard Model via K\n->pi pi decays. In particular we focus upon the calculation of the I=0 channel\namplitude A_0, for which obtaining physical kinematics requires more\nsophisticated techniques than those used for the I=2-channel decay. We discuss\nour chosen techniques along with preliminary demonstrations of their\napplication to simpler lattice quantities, and finally discuss our progress in\ngenerating the large-volume, physical-pion-mass ensembles that will be used to\nperform the A_0 calculation.",
        "positive": "Non-Perturbative Renormalisation using Domain Wall Fermions: The viability of the Non-Perturbative Renormalisation (NPR) method of the\nRome/Southampton group is studied, for the first time, in the context of domain\nwall fermions. The procedure is used to extract the renormalisation\ncoefficients of the various quark bilinears, as well as the four-fermion\noperators relevant to the $\\Delta S=2$ effective Hamiltonian. The\nrenormalisation of the $\\Delta S=1$ Hamiltonian is also discussed."
    },
    {
        "anchor": "Correlations of center flux in SU(2) Yang-Mills theory: By using the method of center projection the center vortex part of the gauge\nfield is isolated and its propagator is evaluated in the center Landau gauge,\nwhich minimizes the open 3-dimensional Dirac volumes of non-trivial center\nlinks bounded by the closed 2-dimensional center vortex surfaces. The center\nfield propagator is found to dominate the gluon propagator (in Landau gauge) in\nthe low momentum regime and to give rise to an OPE correction to the latter of\n$\\sqrt{\\sigma} /p^3 $.The screening mass of the center vortex field vanishes\nabove the critical temperature of the deconfinement phase transition, which\nnaturally explains the second order nature of this transition consistently with\nthe vortex picture. Finally, the ghost propagator of maximal center gauge is\nfound to be infrared finite and thus shows no signal of confinement.",
        "positive": "Numerical studies of confinement in the Landau gauge by the larger\n  lattice simulation: Figure 1 and Figure 2(right) are replaced and the slope parameter $\\alpha_D$\nis corrected to -0.4."
    },
    {
        "anchor": "A High Statistics Study of Flavour-Singlet Mesons with Staggered\n  Fermions: We present some early results from a high statistics study of the scalar and\npseudoscalar singlet sectors of lattice QCD using 2+1 flavours of Asqtad\nimproved staggered fermions. The use of the Asqtad action has allowed us to\ngenerate an unprecedented number of configurations at 2 lattice spacings which\non completion we hope will give us a significantly improved view of both the\nscalar and pseudoscalar singlet sectors.",
        "positive": "Towards leading isospin breaking effects in mesonic masses with $O(a)$\n  improved Wilson fermions: We present an exploratory study of leading isospin breaking effects in\nmesonic masses using $O(a)$ improved Wilson fermions. Isospin symmetry is\nexplicitly broken by distinct masses and electric charges of the up and down\nquarks. In order to be able to make use of existing isosymmetric QCD gauge\nensembles we apply reweighting techniques. The path integral describing QCD+QED\nis expanded perturbatively in powers of the light quarks' mass deviations and\nthe electromagnetic coupling. We employ QED$_{\\mathrm{L}}$ as a finite volume\nformulation of QED."
    },
    {
        "anchor": "Fast and flexible implementations of Wilson, Brillouin and Susskind\n  fermions in lattice QCD: A modern Fortran implementation of three Dirac operators (Wilson, Brillouin,\nSusskind) in lattice QCD is presented, based on OpenMP shared-memory\nparallelization and SIMD pragmas. The main idea is to apply a Dirac operator to\n$N_v$ vectors simultaneously, to ease the memory bandwidth bottleneck. All\nindex computations are left to the compiler and maximum weight is given to\nportability and flexibility. The lattice volume, $N_x N_y N_z N_t$, the number\nof colors, $N_c$, and the number of right-hand sides, $N_v$, are parameters\ndefined at compile time. Several memory layout options are compared. The code\nperforms well on modern many-core architectures (480 Gflop/s, 880 Gflop/s, and\n780 Gflop/s with $N_v=12$ for the three operators in single precision on a\n72-core KNL processor, a $2\\times24$-core Skylake node yields similar results).\nExplicit run-time tests with CG/BiCGstab inverters confirm that the memory\nlayout is relevant for the KNL, but less so for the Skylake architecture. The\nancillary code distribution contains all routines, including the single,\ndouble, and mixed precision Krylov space solvers, to render it self-contained\nand ready-to-use.",
        "positive": "Nucleon axial form factors from two-flavour Lattice QCD: We present preliminary results on the axial form factor $G_A(Q^2)$ and the\ninduced pseudoscalar form factor $G_P(Q^2)$ of the nucleon. A systematic\nanalysis of the excited-state contributions to form factors is performed on the\nCLS ensemble `N6' with $m_\\pi = 340 \\ \\text{MeV}$ and lattice spacing $a \\sim\n0.05 \\ \\text{fm}$. The relevant three-point functions were computed with\nsource-sink separations ranging from $t_s \\sim 0.6 \\ \\text{fm}$ to $t_s \\sim \\\n1.4 \\ \\text{fm}$. We observe that the form factors suffer from non-trivial\nexcited-state contributions at the source-sink separations available to us. It\nis noted that naive plateau fits underestimate the excited-state contributions\nand that the method of summed operator insertions correctly accounts for these\neffects."
    },
    {
        "anchor": "Application of a coordinate space method for the evaluation of lattice\n  Feynman diagrams in two dimensions: We apply a new coordinate space method for the evaluation of lattice Feynman\ndiagrams suggested by L\\\"uscher and Weisz to field theories in two dimensions.\nOur work is to be presented for the theories with massless propagators. The\nmain idea is to deal with the integrals in position space by making use of the\nrecursion relation for the free propagator $G(x)$ which allows to compute the\npropagator recursively by its values around origin. It turns out that the\nmethod is very efficient and gives very precise results. We illustrate the\ntechnique by evaluating a number of two- and three-loop diagrams explicitly.",
        "positive": "Elucidating the sign problem through noise distributions: Due to the presence of light pions in the theory, lattice QCD at finite\ndensities suffers from issues with noise in both grand canonical and canonical\nformulations. We study two different formulations of the Nambu-Jona-Lasinio\nmodel reduced to 2+1 dimensions at large N, where N is the number of flavors.\nAt finite chemical potential one formulation has a severe sign problem and a\nfermion correlator which displays a broad probability distribution with small\nmean. In the other we find no sign problem and a distribution amenable to the\ncumulant expansion techniques developed in earlier work."
    },
    {
        "anchor": "The running coupling from gluon and ghost propagators in the Landau\n  gauge: Yang-Mills theories with adjoint fermions: Non-Abelian gauge theories with fermions transforming in the adjoint\nrepresentation of the gauge group (AdjQCD) are a fundamental ingredient of many\nmodels that describe the physics beyond the Standard Model. Two relevant\nexamples are N=1 Supersymmetric Yang-Mills (SYM) theory and Minimal Walking\nTechnicolor, which are gauge theories coupled to one adjoint Majorana and two\nadjoint Dirac fermions, respectively. While confinement is a property of N=1\nSYM, Minimal Walking Technicolor is expected to be infrared conformal. We study\nthe propagators of ghost and gluon fields in the Landau gauge to compute the\nrunning coupling in the MiniMom scheme. We analyze several different ensembles\nof lattice Monte Carlo simulations for the SU(2) adjoint QCD with Nf=1/2, 1,\n3/2, and 2 Dirac fermions. We show how the running of the coupling changes as\nthe number of interacting fermions is increased towards the conformal window.",
        "positive": "Ratios of the hadronic contributions to the lepton $g-2$ from Lattice\n  QCD+QED simulations: The ratios among the leading-order (LO) hadronic vacuum polarization (HVP)\ncontributions to the anomalous magnetic moments of electron, muon and\ntau-lepton, $a_{\\ell=e,\\mu \\tau}^{HVP,LO}$, are computed using lattice QCD+QED\nsimulations. The results include the effects at order $O(\\alpha_{em}^2)$ as\nwell as the electromagnetic and strong isospin-breaking corrections at orders\n$O(\\alpha_{em}^3)$ and $O(\\alpha_{em}^2(m_u-m_d))$, respectively, where\n$(m_u-m_d)$ is the $u$- and $d$-quark mass difference. We employ the gauge\nconfigurations generated by the Extended Twisted Mass Collaboration with\n$N_f=2+1+1$ dynamical quarks at three values of the lattice spacing ($a \\simeq\n0.062, 0.082, 0.089$ fm) with pion masses in the range 210 - 450 MeV. We show\nthat in the case of the electron-muon ratio the hadronic uncertainties in the\nnumerator and in the denominator largely cancel out, while in the cases of the\nelectron-tau and muon-tau ratios such a cancellation does not occur. For the\nelectron-muon ratio we get $R_{e/\\mu } \\equiv (m_\\mu/m_e)^2 (a_e^{HVP,LO} /\na_\\mu^{HVP,LO}) = 1.1456~(83)$ with an uncertainty of $\\simeq 0.7 \\%$. Our\nresult, which represents an accurate Standard Model (SM) prediction, agrees\nvery well with the estimate obtained using the results of dispersive analyses\nof the experimental $e^+ e^- \\to$ hadrons data. Instead, it differs by $\\simeq\n2.7$ standard deviations from the value expected from present electron and muon\n(g - 2) experiments after subtraction of the current estimates of the QED,\nelectro-weak, hadronic light-by-light and higher-order HVP contributions,\nnamely $R_{e/\\mu} = 0.575~(213)$. An improvement of the precision of both the\nexperiment and the QED contribution to the electron (g - 2) by a factor of\n$\\simeq 2$ could be sufficient to reach a tension with our SM value of the\nratio $R_{e/\\mu }$ at a significance level of $\\simeq 5$ standard deviations."
    },
    {
        "anchor": "Thermal modifications of quarkonia and heavy quark diffusion from a\n  comparison of continuum-extrapolated lattice results to perturbative QCD: We investigate the in-medium modifications of heavy quarkonia in the vector\nchannel and the heavy quark diffusion coefficient by comparing Euclidean\ncorrelators from the lattice to a perturbative spectral function. On the\nlattice side, we work with continuum extrapolated data from four different\nlarge and fine lattices with Clover-improved Wilson fermions in the quenched\napproximation at five temperatures (0.75, 1.1, 1.3, 1.5 and 2.25$T_c$). On the\nperturbative side, we use a combination of pNRQCD and vacuum asymptotics to\ndescribe the spectral function. After accounting for systematic errors, we\nobtain a spectral function that is suited to describe the bound state region.\nThis spectral function describes charmonium well without a resonance peak at\nany of our analyzed temperatures above $T_c$, while we observe a thermally\nbroadened resonance peak for bottomonium that is only melted at our largest\ntemperature, $2.25T_c$. For the transport contribution we assume a Breit-Wigner\nshaped peak and find that the drag coefficient of charm quarks is larger than\nthat of bottom quarks.",
        "positive": "Nucleon isovector form factors from domain-wall lattice QCD at the\n  physical mass: The current status of lattice-QCD numerical calculations by joint LHP, RBC,\nand UKQCD collaborations of nucleon isovector vector- and axialvector-current\nform factors using a 2+1-flavor dynamical domain-wall fermions lattice QCD\nensemble generated jointly by RBC and UKQCD collaborations are presented. The\nlattice spacing is set at about 0.1141(3) fm, and the lattice spatial extent is\n48 spacings or about 5.4750(14) fm. The strange and degenerate up and down\nquark mass values are set at their essentially physical values to provide the\nphysical $\\Omega$ mass and a degenerate pion mass of 0.1392(2) GeV. Our nucleon\nmass estimate is about 0.947(6) GeV. Possible excited-state contaminations in\nthe calculated vector- and axialvector-current form factors are hidden below\nlarger statistical noises. The numerical details of the form-factor shape\nparameters, such as the mean squared radii, the anomalous magnetic moment, or\nthe pseudoscalar coupling extracted from the form factors, are described, along\nwith comparisons of different approaches used to extract them."
    },
    {
        "anchor": "Perfect discretizations of differential operators: We investigate an approach for the numerical solution of differential\nequations which is based on the perfect discretization of actions. Such perfect\ndiscretizations show up at the fixed points of renormalization group\ntransformations. This technique of integrating out the high momentum degrees of\nfreedom with a path integral has been mainly used in lattice field theory,\ntherefore our study of its application to PDE's explores new possibilities. We\ncalculate the perfect discretized Laplace operator for several non-trivial\nboundary conditions analytically and numerically. Then we construct a\nparametrization of the perfect Laplace operator and we show that with this\nparametrization discretization errors -- or computation time -- can be reduced\ndramatically compared to the standard discretization.",
        "positive": "The $\u03c0\u03b3\\to \u03c0\u03c0$ transition and the $\u03c1$ radiative decay\n  width from lattice QCD: We report a lattice QCD determination of the $\\pi\\gamma \\to \\pi\\pi$\ntransition amplitude for the $P$-wave, $I=1$ two-pion final state, as a\nfunction of the photon virtuality and $\\pi\\pi$ invariant mass. The calculation\nwas performed with $2+1$ flavors of clover fermions at a pion mass of\napproximately $320$ MeV, on a $32^3 \\times 96$ lattice with $L\\approx 3.6$ fm.\nWe construct the necessary correlation functions using a combination of smeared\nforward, sequential and stochastic propagators, and determine the finite-volume\nmatrix elements for all $\\pi\\pi$ momenta up to $|\\vec{P}|= \\sqrt{3}\n\\frac{2\\pi}{L}$ and all associated irreducible representations. In the mapping\nof the finite-volume to infinite-volume matrix elements using the\nLellouch-L\\\"uscher factor, we consider two different parametrizations of the\n$\\pi\\pi$ scattering phase shift. We fit the $q^2$ and $s$ dependence of the\ninfinite-volume transition amplitude in a model-independent way using series\nexpansions, and compare multiple different truncations of this series. Through\nanalytic continuation to the $\\rho$ resonance pole, we also determine the\n$\\pi\\gamma \\to \\rho$ resonant transition form factor and the $\\rho$ meson\nphotocoupling, and obtain $|G_{\\rho\\pi\\gamma}| = 0.0802(32)(20)$."
    },
    {
        "anchor": "Real-time correlators in 3+1D thermal lattice gauge theory: Real-time quantities like spectral functions and transport coefficients are\ncrucial for a proper understanding of the quark-gluon plasma created in\nrelativistic heavy-ion collisions. Their numerical computation is plagued by a\nsevere sign problem inherent in the real-time formulation of lattice field\ntheories. In this letter, we present the first direct ab-initio computation of\nunequal-time correlation functions in non-Abelian lattice gauge theory, which\nare necessary to extract real-time quantities. We demonstrate non-trivial\nconsistency relations among correlators, time-translation invariance, and\nagreement with Monte-Carlo results for thermal equilibrium in 3+1 dimensions by\nemploying our stabilized complex Langevin method. Our work sets the stage to\nextract real-time observables in lattice gauge theory in a first-principles\nreal-time framework.",
        "positive": "The new definition of lattice gauge fields and the Landau gauge: The Landau gauge fixing algorithm in the new definition of gauge fields is\npresented. In this algorithm a new solver of the Poisson equations based on the\nGreen's function method is used. Its numerical performance of the gauge fixing\nalgorithm is presented. Performance of the smeared gauge fixing in SU(3) is\nalso investigated."
    },
    {
        "anchor": "Dirac operator index and topology of lattice gauge fields: The fermionic topological charge of lattice gauge fields, given in terms of a\nspectral flow of the Hermitian Wilson--Dirac operator, or equivalently, as the\nindex of Neuberger's lattice Dirac operator, is shown to have analogous\nproperties to L\\\"uscher's geometrical lattice topological charge. The main new\nresult is that it reduces to the continuum topological charge in the classical\ncontinuum limit. (This is sketched here; the full proof will be given in a\nsequel to this paper.) A potential application of the ideas behind fermionic\nlattice topological charge to deriving a combinatorial construction of the\nsignature invariant of a 4-manifold is also discussed.",
        "positive": "Preconditioning Maximal Center Gauge with Stout Link Smearing in SU(3): Center vortices are studied in SU(3) gauge theory using Maximal Center Gauge\n(MCG) fixing. Stout link smearing and over-improved stout link smearing are\nused to construct a preconditioning gauge field transformation, applied to the\noriginal gauge field before fixing to MCG. We find that preconditioning\nsuccessfully achieves higher gauge fixing maxima. We observe a reduction in the\nnumber of identified vortices when preconditioning is used, and also a\nreduction in the vortex-only string tension."
    },
    {
        "anchor": "Effects of a strong magnetic field on the QCD flux tube: In this work we investigate the effect of an external magnetic field B on the\nshape of flux tubes in QCD by means of lattice simulations, performed with\nN_f=2+1 flavors of stout improved dynamical staggered quarks with physical\nmasses. After having discussed some difficulties in the practical definition of\nthe flux tube at B=0, we show that these ambiguities do not affect the\ndetermination of the flux tube modifications induced by the magnetic field.\nDifferent results are obtained depending on the relative orientations of the\nflux tube and of the magnetic field: they confirm that the magnetic field acts\nas transverse confinement catalyser and longitudinal confinement inhibitor;\nmoreover, the flux tube itself loses its axial symmetry when it is not directed\nalong the magnetic background.",
        "positive": "Dual vortices in Abelian projected SU(2) in the Polyakov gauge: We study dual Abrikosov vortices in Abelian projected SU(2) gauge theory in\nthe Polyakov gauge. We show that vortices are present in this gauge but they\nare suppressed with respect to the maximal Abelian gauge. We interpret this\ndifference in terms of the shielding of the electric charge by the charged\ncoset fields."
    },
    {
        "anchor": "The Slab Method to Measure the Topological Susceptibility: In simulations of a model with topological sectors, algorithms which proceed\nin small update steps tend to get stuck in one sector, especially on fine\nlattices. This distorts the numerical results; in particular it is not\nstraightforward to measure the topological susceptibility chi_t. We test a\nmethod to measure chi_t even if configurations from only one sector are\navailable. It is based on the topological charges in sub-volumes, which we\ndenote as \"slab\". This enables the evaluation of chi_t, as we demonstrate with\nnumerical results for non-linear sigma-models and for 2-flavour QCD. In the\nlatter case, the gradient flow is applied for the smoothing of the gauge\nconfigurations, and the slab method results for chi_t are stable over a broad\nrange of flow times.",
        "positive": "Decorrelation of the topological charge in tempered Hybrid Monte Carlo\n  simulations of QCD: We study the improvement of simulations of QCD with dynamical Wilson fermions\nby combining the Hybrid Monte Carlo algorithm with parallel tempering. As an\nindicator for decorrelation we use the topological charge."
    },
    {
        "anchor": "Dynamical generation of a gauge symmetry in the Double-Exchange model: It is shown that a bosonic formulation of the double-exchange model, one of\nthe classical models for magnetism, generates dynamically a gauge-invariant\nphase in a finite region of the phase diagram. We use analytical methods, Monte\nCarlo simulations and Finite-Size Scaling analysis. We study the transition\nline between that region and the paramagnetic phase. The numerical results show\nthat this transition line belongs to the Universality Class of the\nAntiferromagnetic RP(2) model. The fact that one can define a Universality\nClass for the Antiferromagnetic RP(2) model, different from the one of the O(N)\nmodels, is puzzling and somehow contradicts naive expectations about\nUniversality.",
        "positive": "A new Bayesian approach to the reconstruction of spectral functions: We present a novel approach for the reconstruction of spectra from Euclidean\ncorrelator data that makes close contact to modern Bayesian concepts. It is\nbased upon an axiomatically justified dimensionless prior distribution, which\nin the case of constant prior function $m(\\omega)$ only imprints smoothness on\nthe reconstructed spectrum. In addition we are able to analytically integrate\nout the only relevant overall hyper-parameter $\\alpha$ in the prior, removing\nthe necessity for Gaussian approximations found e.g. in the Maximum Entropy\nMethod. Using a quasi-Newton minimizer and high-precision arithmetic, we are\nthen able to find the unique global extremum of $P[\\rho|D]$ in the full\n$N_\\omega\\gg N_\\tau$ dimensional search space. The method actually yields\ngradually improving reconstruction results if the quality of the supplied input\ndata increases, without introducing artificial peak structures, often\nencountered in the MEM. To support these statements we present mock data\nanalyses for the case of zero width delta peaks and more realistic scenarios,\nbased on the perturbative Euclidean Wilson Loop as well as the Wilson Line\ncorrelator in Coulomb gauge."
    },
    {
        "anchor": "Search for the S=+1 pentaquarks in quenched lattice QCD: We study spin $\\frac12$ hadronic states in quenched lattice QCD to search for\na possible $S=+1$ pentaquark resonance. Our work is the first systematic\nlattice QCD study which properly carries out the following analyses: {\\it (1)\nthe careful extraction of the first two low energy states with very high\nstatistics and the variational method} and {\\it (2) the study of volume\ndependences of eigenenergies and spectral weights to distinguish resonance\nstates from scattering states}.\n  Simulations are carried out on $8^3\\times 24$, $10^3\\times 24$, $12^3\\times\n24$ and $16^3\\times 24$ lattices at $\\beta$=5.7 with the standard plaquette\ngauge action and the Wilson quark action. Our result indicates the existence of\na resonance state lying slightly above the NK threshold in\n$(I,J^P)=(0,\\frac12^-)$ channel in quenched QCD.",
        "positive": "Baryon Masses in Partially Quenched Heavy Hadron Chiral Perturbation\n  Theory: The masses of baryons containing a heavy quark are calculated to\nnext-to-leading order in partially quenched heavy hadron chiral perturbation\ntheory. Calculations are performed for three light flavors in the isospin limit\nand additionally for two light non-degenerate flavors. The results presented\nare necessary for extrapolating lattice QCD and partially quenched lattice QCD\ncalculations of the heavy hadron masses."
    },
    {
        "anchor": "Non-perturbative improvement and renormalization of the axial current in\n  N_f=3 lattice QCD: We report on a non-perturbative computation of the renormalization factor Z_A\nof the axial vector current in three-flavour O(a) improved lattice QCD with\nWilson quarks and tree-level Symanzik improved gauge action and also recall our\nrecent determination of the improvement coefficient c_A. Our normalization and\nimprovement conditions are formulated at constant physics in a Schr\\\"odinger\nfunctional setup. The normalization condition exploits the full, massive axial\nWard identity to reduce finite quark mass effects in the evaluation of Z_A and\ncorrelators with boundary wave functions to suppress excited state\ncontributions in the pseudoscalar channel.",
        "positive": "Large-order NSPT for lattice gauge theories with fermions: the plaquette\n  in massless QCD: Numerical Stochastic Perturbation Theory (NSPT) allows for perturbative\ncomputations in quantum field theory. We present an implementation of NSPT that\nyields results for high orders in the perturbative expansion of lattice gauge\ntheories coupled to fermions. The zero-momentum mode is removed by imposing\ntwisted boundary conditions; in turn, twisted boundary conditions require us to\nintroduce a smell degree of freedom in order to include fermions in the\nfundamental representation. As a first application, we compute the critical\nmass of two flavours of Wilson fermions up to order $O(\\beta^{-7})$ in a\n${\\mathrm{SU}}(3)$ gauge theory. We also implement, for the first time,\nstaggered fermions in NSPT. The residual chiral symmetry of staggered fermions\nprotects the theory from an additive mass renormalisation. We compute the\nperturbative expansion of the plaquette with two flavours of massless staggered\nfermions up to order $O(\\beta^{-35})$ in a ${\\mathrm{SU}}(3)$ gauge theory, and\ninvestigate the renormalon behaviour of such series. We are able to subtract\nthe power divergence in the Operator Product Expansion (OPE) for the plaquette\nand estimate the gluon condensate in massless QCD. Our results confirm that\nNSPT provides a viable way to probe systematically the asymptotic behaviour of\nperturbative series in QCD and, eventually, gauge theories with fermions in\nhigher representations."
    },
    {
        "anchor": "Interactions between Lattice Hadrons: The effective residual interaction for a system of hadrons has a long\ntradition in theoretical physics. It has been mostly addressed in terms of\nboson exchange models. The aim of this review is to describe approaches based\non lattice field theory and numerical simulation. At the present time this\nsubject matter is in an exploratory stage. A large array of problems waits to\nbe tackled, so that known features of hadron-hadron interactions will\neventually be understood in a model-independent way. The lattice formulation,\nbeing capable of dealing with the nonperturbative regime, describes\nstrong-interaction physics from first principles, i.e. quantum chromodynamics\n(QCD). Although the physics of hadron-hadron interactions may be intrinsically\ncomplicated, the methods used in lattice simulations are simple: For the most\npart they are based on standard mass calculations. This chapter addresses\ncommonly used techniques, within QCD and also simpler lattice models, describes\nimportant results, and also gives some insight into numerical methods for\nmulti-quark systems.",
        "positive": "Charmonium spectral functions in Nf=2 QCD: We report on a study of charmonium at high temperature in 2-flavour QCD. This\nis the first such study with dynamical fermions. Using an improved anisotropic\nlattice action, spectral functions are extracted from correlators in the vector\nand pseudoscalar channels. No signs of medium-induced suppression of the ground\nstates are seen for temperatures up to 1.5T_c, while at T~2T_c there are clear\nsigns of modifications. The current systematic and statistical uncertainties in\nour data, in particular the relatively coarse lattice and small volume, do not\nallow us to draw a firm conclusion at this stage."
    },
    {
        "anchor": "Couplings of hybrid operators to ground and excited states of bottomonia: We analyze the overlap of local color-octet meson operators with the\n$\\Upsilon$ and the $\\eta_b$ and their low-lying excited states, especially the\nfirst radial excitations. Our analysis is based on NRQCD and includes all terms\nup to order $v^4$. We use a variety of source and sink operators as a basis for\nthe variational method, which enables us to clearly separate the mass\neigenstates and hence to extract the desired amplitudes. The results show the\nusefulness of the variational method for determining couplings to excited\nhadronic states.",
        "positive": "Non-perturbative Renormalization Constants using Ward Identities: We extend the application of axial Ward identities to calculate $b_A, b_P$\nand $b_T$, coefficients that give the mass dependence of the renormalization\nconstants of the corresponding bilinear operators in the quenched theory. The\nextension relies on using operators with non-degenerate quark masses. It allows\na complete determination of the O(a) improvement coefficients for bilinears in\nthe quenched approximation using Ward Identities alone. Only the scale\ndependent normalization constants $Z_P^0$ (or $Z_S^0$) and $Z_T$ are\nundetermined. We present results of a pilot numerical study using hadronic\ncorrelators."
    },
    {
        "anchor": "Numerical determination of monopole scaling dimension in\n  parity-invariant three-dimensional non-compact QED: We present a direct Monte-Carlo determination of the scaling dimension of a\ntopological defect operator in the infrared fixed point of a three-dimensional\ninteracting quantum field theory. For this, we compute the free energy to\nintroduce the background gauge field of the $Q=1$ monopole-antimonopole pair in\nthree-dimensional non-compact QED with $N=2,4$ and $12$ flavors of massless\ntwo-component fermions, and study its asymptotic logarithmic dependence on the\nmonopole-antimonopole separation. We estimate the scaling dimension in the\n$N=12$ case to be consistent with the large-$N$ (free fermion) value. We find\nthe deviations from this large-$N$ value for $N=2$ and $4$ are positive but\nsmall, implying that the higher order corrections in the large-$N$ expansion\nbecome mildly important for $N=2,4$.",
        "positive": "Neutral meson oscillations in the Standard Model and beyond from Nf=2\n  Twisted Mass Lattice QCD: We present the ETMC results for the bag parameters describing the neutral\nkaon mixing in the Standard Model and beyond and preliminary results for the\nbag parameters controlling the short distance contributions in the\nD^0-\\bar{D}^0 oscillations. We also present preliminary results for the B_{Bd},\nB_{Bs}, B_{Bs}/B_{Bd} and \\xi -parameter controlling B^0_-\\bar{B}^0\noscillations in the Standard Model employing the so-called ratio method. Using\nNf=2 maximally twisted sea quarks and Osterwalder-Seiler valence quarks we\nachieve both O(a)-improvement and continuum like renormalization pattern.\nSimulations are performed at three-values of the lattice spacing and several\nvalues of quark masses in the light, strange, charm region and above charm up\nto ~2.5m_c. Our results are extrapolated to the continuum limit and\nextrapolated/interpolated to the physical quark masses."
    },
    {
        "anchor": "Phase structure with nonzero $\u0398_{\\rm QCD}$ and twisted mass\n  fermions: We determine the phase diagram and chiral condensate for lattice QCD with two\nflavors of twisted-mass fermions in the presence of nondegenerate up and down\nquarks, discretization errors and a nonzero value of $\\Theta_{\\rm QCD}$.\nAlthough such a theory has a complex action and cannot, at present, be\nsimulated, the results are needed to understand how to tune to maximal twist in\nthe presence of electromagnetism, a topic discussed in a companion paper. We\nfind that, in general, the only phase structure is a first-order transition of\nfinite length. Pion masses are nonvanishing throughout the phase plane except\nat the endpoints of the first-order line. Only for extremal values of the twist\nangle and $\\Theta_{\\rm QCD}$ ($\\omega=0$ or $\\pi/2$ and $\\Theta_{\\rm QCD}=0$ or\n$\\pi$) are there second-order transitions.",
        "positive": "Topological insights in many-flavor QCD on the lattice: LatKMI Collaboration discusses the topological insights in many-flavor QCD on\nthe lattice. We explore walking/conformal/confining phase in $N_\\mathrm{f}$ =\n4, 8 and 12 (in particular $N_\\mathrm{f}$ = 8) lattice QCD via the topological\ncharge and susceptibility, eigenvalues and anomalous dimension."
    },
    {
        "anchor": "In-medium dispersion relations of charmonia studied by maximum entropy\n  method: We study in-medium spectral properties of charmonia in the vector and\npseudoscalar channels at nonzero momenta on quenched lattices, especially\nfocusing on their dispersion relation and weight of the peak. We measure the\nlattice Euclidean correlation functions with nonzero momenta on the anisotropic\nquenched lattices and study the spectral functions with the maximum entropy\nmethod. The dispersion relations of charmonia and the momentum dependence of\nthe weight of the peak are analyzed with the maximum entropy method together\nwith the errors estimated probabilistically in this method. We find significant\nincrease of the masses of charmonia in medium. It is also found that the\nfunctional form of the charmonium dispersion relations is not changed from that\nin the vacuum within the error even at $T\\simeq1.6T_c$ for all the channels we\nanalyzed.",
        "positive": "Recent results on self-dual configurations on the torus: We review the recent progress on our understanding of self-dual SU(N)\nYang-Mills configurations on the torus."
    },
    {
        "anchor": "The N_f=0 heavy quark potential and perturbation theory: The potential of a static quark-antiquark pair is studied in the range 0.05\nfm $<$ r $<$ 0.8 fm, employing a sequence of lattices up to 64^4. The continuum\nquantities are evaluated by extrapolation of the data at finite lattice\nspacing. The results are compared with the perturbation theory predictions\nobtained from the solution of the renormalization group equation for the\ncoupling. The renormalization scheme must be chosen carefully. No evidence for\nlarge non-perturbative effects at short distances is seen.",
        "positive": "Monopoles in lattice Electroweak theory: There exist several types of monopole - like topological defects in\nElectroweak theory. We investigate properties of these objects using lattice\nnumerical methods. The intimate connection between them and the dynamics of the\ntheory is established.\n  We find that the density of Nambu monopoles cannot be predicted by the choice\nof the initial parameters of Electroweak theory and should be considered as the\nnew external parameter of the theory. We also investigate the difference\nbetween the versions of Electroweak theory with the gauge groups $SU(2)\\otimes\nU(1)$ and $SU(2)\\otimes U(1)/Z_2$. We do not detect any difference at $\\alpha\n\\sim {1/128}$. However, such a difference appears in the unphysical region of\nlarge coupling constant $\\alpha > 0.1$."
    },
    {
        "anchor": "Momentum-dependence of charmonium spectral functions from lattice QCD: We compute correlators and spectral functions for J/psi and eta_c mesons at\nnonzero momentum on anisotropic lattices with Nf=2. We find no evidence of\nsignificant momentum dependence at the current level of precision. In the\npseudoscalar channel, the ground state appears to survive up to T~450MeV or\n2.1T_c. In the vector channel, medium modifications may occur at lower\ntemperatures.",
        "positive": "Large-$N_c$ gauge theory and chiral random matrix theory: We discuss how the $1/N_c$ expansion and the chiral random matrix theory\n($\\chi$RMT) can be used in the study of large-$N_c$ gauge theories. We first\nclarify the parameter region in which each of these two approaches is valid:\nwhile the fermion mass $m$ is fixed in the standard large-$N_c$ arguments ('t\nHooft large-$N_c$ limit), $m$ must be scaled appropriately with a certain\nnegative power of $N_c$ in order for the gauge theories to be described by the\n$\\chi$RMT. Then, although these two limits are not compatible in general, we\nshow that the breakdown of chiral symmetry can be detected by combining the\nlarge-$N_c$ argument and the $\\chi$RMT with some cares. As a concrete example,\nwe numerically study the four dimensional $SU(N_c)$ gauge theory with $N_f=2$\nheavy adjoint fermions, introduced as the center symmetry preserver keeping the\ninfrared physics intact, on a $2^4$ lattice. By looking at the low-lying\neigenvalues of the Dirac operator for a massless probe fermion in the adjoint\nrepresentation, we find that the chiral symmetry is indeed broken with the\nexpected breaking pattern. This result reproduces a well-known fact that the\nchiral symmetry is spontaneously broken in the pure $SU(N_c)$ gauge theory in\nthe large-$N_c$ and the large-volume limit, and therefore supports the validity\nof the combined approach. We also provide the interpretation of the gap and\nunexpected $N_c$-scaling, both of which are observed in the Dirac spectrum."
    },
    {
        "anchor": "Interglueball potential in lattice SU(N) gauge theories: The dynamics of the glueballs is important in the context of the experimental\nsearch as well as for understanding the non-Abelian gauge theory. The glueballs\nof the dark $SU(N_c)$ Yang-Mills theory are also good candidates of dark\nmatter. In this proceedings contribution, we report on the result of the\nlattice calculation of the interglueball potential of the Yang-Mills theory\nwith the color numbers $N_c=2,3,4$, with a detailed inspection of the\nsystematics due to the discretization.",
        "positive": "A New Lattice Action for Studying Topological Charge: We propose a new lattice action for non-abelian gauge theories, which will\nreduce short-range lattice artifacts in the computation of the topological\nsusceptibility. The standard Wilson action is replaced by the Wilson action of\na gauge covariant interpolation of the original fields to a finer lattice. If\nthe latter is fine enough, the action of all configurations with non-zero\ntopological charge will satisfy the continuum bound. As a simpler example we\nconsider the $O(3)$ $\\sigma$-model in two dimensions, where a numerical\nanalysis of discretized continuum instantons indicates that a finer lattice\nwith half the lattice spacing of the original is enough to satisfy the\ncontinuum bound."
    },
    {
        "anchor": "Gluon Propagators in 3D SU(2) Theory and Effects of Gribov Copies: Infrared behavior of the Landau gauge gluon propagators is studied\nnumerically in the 3d SU(2) gauge theory on the lattice. A special accent is\nmade on the study of Gribov copy effect. For this study we employ an efficient\ngauge-fixing algorithm and a large number of gauge copies (up to 280 copies per\nconfiguration). It is shown that, in the deep infrared region, the Gribov copy\neffects are very significant. Also we show that, in the infinite-volume limit,\nthe zero-momentum value of the propagator does not vanish.",
        "positive": "Results and techniques for higher order calculations within the\n  gradient-flow formalism: We describe in detail the implementation of a systematic perturbative\napproach to observables in the QCD gradient-flow formalism. This includes a\ncollection of all relevant Feynman rules of the five-dimensional field theory\nand the composite operators considered in this paper. Tools from standard\nperturbative calculations are used to obtain Green's functions at finite flow\ntime $t$ at higher orders in perturbation theory. The three-loop results for\nthe quark condensate at finite $t$ and the conversion factor for the \"ringed\"\nquark fields to the $\\overline{\\mbox{MS}}$ scheme are presented as\napplications. We also re-evaluate an earlier result for the three-loop gluon\ncondensate, improving on its accuracy."
    },
    {
        "anchor": "Electric and magnetic Landau-gauge gluon propagators in\n  finite-temperature SU(2) gauge theory: We perform lattice simulations in pure-SU(2) Yang-Mills theory to investigate\nhow the infrared behavior of electric and magnetic gluon propagators in Landau\ngauge is affected by temperature. We consider the largest lattices to date, in\nan attempt to keep systematic errors under control. Electric and magnetic\nscreening masses are calculated through an Ansatz from the zero-temperature\ncase, based on complex-conjugate poles for the momentum-space propagators. As\nrecently reported in [1], we find good fits to the proposed form at all\ntemperatures considered, with different ratios of real to imaginary part of the\npole masses for the longitudinal (electric) and transverse (magnetic)\npropagators. The behavior of the magnetic propagator D_T(p) is in agreement\nwith the dimensional-reduction picture, showing infrared suppression (with a\nturnover in momentum) and violation of spectral positivity at all nonzero\ntemperatures considered. The longitudinal propagator D_L(p) appears to reach a\nplateau at small momenta and is subject to severe finite-Nt effects around the\ncritical temperature Tc. As a consequence, only lattices with temporal extent\nNt > 8 seem to be free from systematic errors. After these errors are removed,\nthe infrared-plateau value is considerably reduced around the transition and\nthe sharp peak observed previously for this quantity at Tc is no longer\npresent. The resulting infrared behavior for D_L(p) at Tc is essentially the\nsame as for 0.5Tc . An investigation of the temperature range between 0.5Tc and\nTc reveals that a less pronounced (finite) peak may occur at smaller\ntemperatures, e.g. T ~ 0.9Tc.",
        "positive": "Topological Susceptibility under Gradient Flow: We study the impact of the Gradient Flow on the topology in various models of\nlattice field theory. The topological susceptibility $\\chi_{\\rm t}$ is measured\ndirectly, and by the slab method, which is based on the topological content of\nsub-volumes (\"slabs\") and estimates $\\chi_{\\rm t}$ even when the system remains\ntrapped in a fixed topological sector. The results obtained by both methods are\nessentially consistent, but the impact of the Gradient Flow on the\ncharacteristic quantity of the slab method seems to be different in 2-flavour\nQCD and in the 2d O(3) model. In the latter model, we further address the\nquestion whether or not the Gradient Flow leads to a finite continuum limit of\nthe topological susceptibility (rescaled by the correlation length squared,\n$\\xi^{2}$). This ongoing study is based on direct measurements of $\\chi_{\\rm\nt}$ in $L \\times L$ lattices, at $L/\\xi \\simeq 6$."
    },
    {
        "anchor": "Computation of the improvement coefficient $c_{sw}$ to 1-loop with\n  improved gluon actions: The clover coefficient $\\csw$ is computed at one loop order of perturbation\ntheory for improved gluon actions including six-link loops. The O(a)\nimprovement coefficients for the dimension three isovector composite operators\nbilinear in the quark fields are also calculated.",
        "positive": "Ensemble Quasi-Newton HMC: We present a modification of the Hybrid Monte Carlo algorithm for tackling\nthe critical slowing down of generating Markov chains of lattice gauge\nconfigurations towards the continuum limit. We propose a new method to exchange\ninformation within an ensemble of Markov chains, and use it to construct an\napproximate inverse Hessian matrix of the action inspired from quasi-Newton\nalgorithms for optimization. The kinetic term of the molecular dynamics\nevolution includes the approximate Hessian for long distance couplings among\nthe momenta. We show the result of applying the new algorithm to the $U(1)$\ngauge theory in two dimensions, and discuss our future plans."
    },
    {
        "anchor": "Matching the Bare and MSbar Charm Quark Masses Using Weak Coupling\n  Simulations: We provide a new determination of the charm quark mass using the Highly\nImproved Staggered Quark (HISQ) action, finding m_c(3 GeV) = 0.983(23) GeV. Our\ndetermination makes extensive use of second order lattice perturbation theory\nin matching the bare lattice mass to the MSbar scheme. This matching utilises\nboth traditional diagrammatic perturbation theory and weak coupling\nsimulations. The second of these techniques allows us to extract perturbative\ncoefficients from Monte-Carlo simulations and the process of doing this is laid\nout in some detail here.",
        "positive": "Lorentz symmetry violation in the fermion number anomaly with the chiral\n  overlap operator: Recently, Grabowska and Kaplan proposed a four-dimensional lattice\nformulation of chiral gauge theories on the basis of a chiral overlap operator.\nWe compute the classical continuum limit of the fermion number anomaly in this\nformulation. Unexpectedly, we find that the continuum limit contains a term\nwhich is not Lorentz invariant. The term is, however, proportional to the gauge\nanomaly coefficient, and thus the fermion number anomaly in this lattice\nformulation automatically restores the Lorentz-invariant form when and only\nwhen the anomaly cancellation condition is met."
    },
    {
        "anchor": "Unitary Evolution on a Discrete Phase Space: We construct unitary evolution operators on a phase space with power of two\ndiscretization. These operators realize the metaplectic representation of the\nmodular group SL(2,Z_{2^n}). It acts in a natural way on the coordinates of the\nnon-commutative 2-torus, T_{2^n}^2$ and thus is relevant for non-commutative\nfield theories as well as theories of quantum space-time. The class of\noperators may also be useful for the efficient realization of new quantum\nalgorithms.",
        "positive": "First Lattice QCD Study of Proton Twist-3 GPDs: We present first results on selected twist-3 quark GPDs using the\nquasi-distribution method. This approach relates lattice QCD data and\nlight-cone distribution functions using Large Momentum Effective Theory\n(LaMET). We calculate quark-antiquark correlators of boosted nucleons coupled\nto non-local operators with vector and axial Dirac structure, which is\ntransverse to the momentum boost. We use three values of the momentum boost,\nnamely 0.83, 1.25, 1.67 GeV. The GPDs are defined in the symmetric (Breit)\nframe, which we implement here with 4-vector momentum transfer squared of 0,\n0.69 and 1.39 GeV 2 , all at zero skewness. The calculation is performed using\none ensemble of two degenerate light, a strange and a charm quark ($N_f$ = 2 +\n1 + 1) of maximally twisted mass fermions with a clover term, corresponding to\na pion mass of 260 MeV."
    },
    {
        "anchor": "On the computation of hadron-to-hadron transition matrix elements in\n  lattice QCD: We discuss the accurate determination of matrix elements < f| h_w | i > where\nneither |i> nor |f> is the vacuum state and h_w is some operator. Using\nsolutions of the Generalized Eigenvalue Problem (GEVP) we construct estimators\nfor matrix elements which converge rapidly as a function of the Euclidean time\nseparations involved. |i> and |f> may be either the ground state in a given\nhadron channel or an excited state. Apart from a model calculation, the\nestimators are demonstrated to work well for the computation of the B*B\npi-coupling in the quenched approximation. They are also compared to a standard\nratio as well as to the \"summed ratio method\" of [1,2,3]. In the model, we also\nillustrate the ordinary use of the GEVP for energy levels.",
        "positive": "Loop representation for 2-D Wilson lattice fermions in a scalar\n  background field: We show that the fermion determinant for 2-D Wilson lattice fermions coupled\nto an external scalar field is equivalent to self avoiding loops interacting\nwith the external field. In an application of the resulting formula we\nintegrate the scalar field with a Gaussian action to generate the N-component\nGross-Neveu model. The loop representation for this model is discussed."
    },
    {
        "anchor": "Nucleon resonance structure in the finite volume of lattice QCD: An approach for relating the nucleon resonances extracted from $\\pi N$\nreaction data to lattice QCD calculations has been developed by using the\nfinite-volume Hamiltonian method. Within models of $\\pi N$ reactions, bare\nstates are introduced to parametrize the intrinsic excitations of the nucleon.\nWe show that the resonance pole positions can be related to the probability\n$P_{N^*}(E)$ of finding the bare state, $N^*$, in the $\\pi N$ scattering states\nin infinite volume. We further demonstrate that the probability $P_{N^*}^V(E)$\nof finding the same bare states in the eigenfunctions of the underlying\nHamiltonian in finite volume approaches $P_{N^*}(E)$ as the volume increases.\nOur findings suggest that the comparison of $P_{N^*}(E)$ and $P_{N^*}^V(E)$ can\nbe used to examine whether the nucleon resonances extracted from the $\\pi N$\nreaction data within the dynamical models are consistent with lattice QCD\ncalculation. We also discuss the measurement of $P_{N^*}^V(E)$ directly from\nlattice QCD. The practical differences between our approach and the approach\nusing the L\\\"uscher formalism to relate LQCD calculations to the nucleon\nresonance poles embedded in the data are also discussed.",
        "positive": "Diquark Masses from Lattice QCD: We present first results for diquark correlation functions calculated in\nLandau gauge on the lattice. Masses have been extracted from the long distance\nbehaviour of these correlation functions. We find that the ordering of diquark\nmasses with spin 0 and 1 states in colour anti-triplet and sextet channels is\nin accordance with instanton motivated interaction models. Although we find\nevidence for an attractive interaction in colour anti-triplet states with a\nsplitting between spin 0 and spin 1 diquarks that can account for the mass\nsplitting between the nucleon and the delta, there is no evidence for a deeply\nbound diquark state."
    },
    {
        "anchor": "The Lattice Fermi Surface: The Nambu - Jona-Lasinio model in 2+1 dimensions is simulated for non-zero\nbaryon chemical potential with a diquark source term. No evidence for a BCS\ncondensate or gap is seen at high density; rather, critical behaviour with\nnovel exponents is observed, suggesting that 2d superfluidity as first\ndescribed by Kosterlitz and Thouless is realised, but with the universality\nclass determined by the presence of relativistic fermions.",
        "positive": "Full result for the QCD equation of state with 2+1 flavors: We present a full result for the 2+1 flavor QCD equation of state. All the\nsystematics are controlled, the quark masses are set to their physical values,\nand the continuum extrapolation is carried out. This extends our previous\nstudies [JHEP 0601:089 (2006); 1011:077 (2010)] to even finer lattices and now\nincludes ensembles with Nt = 6,8,10,12 up to Nt = 16. We use a Symanzik\nimproved gauge and a stout-link improved staggered fermion action. Our findings\nconfirm our earlier results. In order to facilitate the direct use of our\nequation of state we make our tabulated results available for download."
    },
    {
        "anchor": "General Physics Motivations for Numerical Simulations of Quantum Field\n  Theory: In this introductory article a brief description of Quantum Field Theories\n(QFT) is presented with emphasis on the distinction between strongly and weakly\ncoupled theories. A case is made for using numerical simulations to solve QCD,\nthe regnant theory describing the interactions between quarks and gluons. I\npresent an overview of what these calculations involve, why they are hard, and\nwhy they are tailor made for parallel computers. Finally, I try to communicate\nthe excitement amongst the practitioners by giving examples of the quantities\nwe will be able to calculate to within a few percent accuracy in the next five\nyears.",
        "positive": "Heavy Meson Masses in the \u03b5-Regime of HM\u03c7PT: The pseudoscalar and vector heavy meson masses are calculated in the\n\\epsilon-regime of Heavy Meson Chiral Perturbation Theory to order \\epsilon^4.\nThe results of this calculation will allow the determination of low-energy\ncoefficients (LECs) directly from Lattice QCD calculations of the heavy mesons\nmasses for lattices that satisfy the \\epsilon-regime criteria. In particular,\nthe LECs that parametrize the NLO volume dependance of the heavy meson masses\nare necessary for evaluating the light pseudoscalar meson (\\pi, K, \\eta) and\nheavy meson ({D^0, D^+, D^+_s}, {B^-,\\bar{B}^0,\\bar{B}^0_s}) scattering phase\nshifts."
    },
    {
        "anchor": "Instantons in the Maximally Abelian Gauge: We investigate the Maximally Abelian (MA) Projection for a single $SU(2)$\ninstanton in continuum gauge theory. We find that there is a class of solutions\nto the differential MA gauge condition with circular monopole loops of radius\n$R$ centered on the instanton of width $\\rho$. However, the MA gauge fixing\nfunctional $G$ decreases monotonically as $R/\\rho \\rightarrow 0$. Its global\nminimum is the instanton in the singular gauge. We point out that interactions\nwith nearby anti-instantons are likely to excite these monopole loops.",
        "positive": "Lattice simulation of the SU(2) chiral model at zero and non-zero pion\n  density: We propose a flux representation based lattice formulation of the partition\nfunction corresponding to the SU(2) principal chiral Lagrangian, including a\nchemical potential and scalar/pseudo-scalar source terms. Lattice simulations\nare then used to obtain non-perturbative properties of the theory, in\nparticular its mass spectrum at zero and non-zero pion density. We also sketch\na method to efficiently measure general one- and two-point functions during the\nworm updates."
    },
    {
        "anchor": "Layer World: Living on a layer in 5D SU(3): We suggest another approach to five-dimensional non-isotropic gauge theory.\nUsing non-perturbative technique we show that already modest interaction\nanisotropy confines heavy bound states to four-dimensional layers, while free\nquarks propagate with almost no penalty into the fifth dimension.",
        "positive": "Non-lattice simulation for supersymmetric gauge theories in one\n  dimension: Lattice simulation of supersymmetric gauge theories is not straightforward.\nIn some cases the lack of manifest supersymmetry just necessitates cumbersome\nfine-tuning, but in the worse cases the chiral and/or Majorana nature of\nfermions makes it difficult to even formulate an appropriate lattice theory. We\npropose to circumvent all these problems inherent in the lattice approach by\nadopting a non-lattice approach in the case of one-dimensional supersymmetric\ngauge theories, which are important in the string/M theory context."
    },
    {
        "anchor": "Exploring chiral dynamics with overlap fermions: This talk presents a lattice study of spontaneous chiral symmetry breaking\nperformed by the JLQCD and TWQCD collaborations with dynamical overlap\nfermions. Our lattice configurations are generated in a fixed topological\nsector. Since finite volume effects, partly due to the fixed global topology,\nare mainly induced by pion fields, the dependence on the lattice volume,\ntopological charge and quark masses can be analytically predicted using chiral\nperturbation theory (ChPT). We find a good agreement of Dirac operator spectrum\ncalculated on the lattice with the ChPT prediction including its finite size\nscalings, through which the chiral condensate is determined with good accuracy.",
        "positive": "Renormalisation of Composite Operators in Lattice Perturbation Theory\n  with Clover Fermions: Non-forward Matrix Elements: We consider the renormalisation of lattice QCD operators with one and two\ncovariant derivatives related to the first and second moments of generalised\nparton distributions and meson distribution amplitudes. Employing the clover\nfermion action we calculate their non-forward quark matrix elements in one-loop\nlattice perturbation theory. For some representations of the hypercubic group\ncommonly used in simulations we determine the sets of all possible mixing\noperators and compute the matrices of renormalisation factors in one-loop\napproximation. We describe how tadpole improvement is applied to the results."
    },
    {
        "anchor": "A 0-dimensional counter-example to rooting?: We provide an example of a 0-dimensional field theory where rooting does not\nwork.",
        "positive": "Simulation of QCD with N_f=2+1 flavors of non-perturbatively improved\n  Wilson fermions: We describe a new set of gauge configurations generated within the CLS\neffort. These ensembles have N_f=2+1 flavors of non-perturbatively improved\nWilson fermions in the sea with the Luescher-Weisz action used for the gluons.\nOpen boundary conditions in time are used to address the problem of topological\nfreezing at small lattice spacings and twisted-mass reweighting for improved\nstability of the simulations. We give the bare parameters at which the\nensembles have been generated and how these parameters have been chosen.\nDetails of the algorithmic setup and its performance are presented as well as\nmeasurements of the pion and kaon masses alongside the scale parameter t_0."
    },
    {
        "anchor": "The chiral condensate of $N_f=2+1$ QCD from the spectrum of the\n  staggered Dirac operator: We compute the chiral condensate of $2+1$ QCD from the mode number of the\nstaggered Dirac operator, performing controlled extrapolations to both the\ncontinuum and the chiral limit. We consider also alternative strategies, based\non the quark mass dependence of the topological susceptibility and of the pion\nmass, and obtain consistent results within errors. Results are also consistent\nwith phenomenological expectations and with previous numerical determinations\nobtained with different lattice discretizations.",
        "positive": "Continuum Limit of Scalar Masses and Mixing Energies: We evaluate the continuum limit of the valence approximation to the mass of\nscalar quarkonium and to the scalar quarkonium-glueball mixing energy for a\nrange of different quark masses. Our results answer several questions raised by\nthe proposed identification of $f_0(1710)$ as composed primarily of the\nlightest scalar glueball."
    },
    {
        "anchor": "Twisted mass quarks and the phase structure of lattice QCD: The phase structure of zero temperature twisted mass lattice QCD is\ninvestigated. We find strong metastabilities in the plaquette observable when\nthe untwisted quark mass assumes positive or negative values. We provide\ninterpretations of this phenomenon in terms of chiral symmetry breaking and the\neffective potential model of Sharpe and Singleton.",
        "positive": "Correlation Function at $\u03b2_t$ in the Disordered Phase of 2D Potts\n  Models: We use Monte Carlo simulations to measure the spin-spin correlation function\nin the disordered phase of two-dimensional $q$-state Potts models with\n$q=10,15$, and $20$ at the first-order transition point $\\beta_t$. To extract\nthe correlation length $\\xi_d$ from the exponential decay of the correlation\nfunction over several decades with the desired accuracy we make extensively use\nof cluster-update techniques and improved estimators. Our results for $\\xi_d$\nare compatible with an analytic formula. As a byproduct we also measure the\nenergy moments in the disordered phase and find very good agreement with a\nrecent large $q$ expansion at $\\beta_t$."
    },
    {
        "anchor": "Field Strength and Monopoles in Dual U(1) Lattice Gauge Theory: In any Abelian gauge theory with an action periodic in the link variables one\ncan perform a duality transformation not only in the partition function, but\nalso in correlation functions including Polyakov loops. The calculation of\nexpectation values in the confinement phase, like electric field strength or\nmonopole currents in the presence of external charges, becomes significantly\nmore efficient simulating the dual theory. We demonstrate this using the\nordinary Wilson action. This approach also allows a quantitative analysis of\nthe dual superconductor model, because the dual transformed U(1) theory can be\nregarded as limit of a dual non-compact Abelian Higgs model. In this way we\nalso try to interpret the behaviour of monopole condensate and string\nfluctuations. Finally we present some applications for simulating the dual U(1)\ngauge theory.",
        "positive": "Electroweak Matrix Elements in the Two-Nucleon Sector from Lattice QCD: We demonstrate how to make rigorous predictions for electroweak matrix\nelements in nuclear systems directly from QCD. More precisely, we show how to\ndetermine the short-distance contributions to low-momentum transfer electroweak\nmatrix elements in the two-nucleon sector from lattice QCD. In potential model\ndescriptions of multi-nucleon systems, this is equivalent to uniquely\ndetermining the meson-exchange currents, while in the context of nuclear\neffective field theory, this translates into determining the coefficients of\nlocal, gauge-invariant, multi-nucleon-electroweak current operators. The\nenergies of the lowest-lying states of two nucleons on a finite volume lattice\nwith periodic boundary conditions in the presence of a background magnetic\nfield are sufficient to determine the local four-nucleon operators that\ncontribute to the deuteron magnetic moment and to the threshold cross-section\nof n + p -> d + gamma. Similarly, the energy-levels of two nucleons immersed in\na background isovector axial weak field can be used to determine the\ncoefficient of the leading local four-nucleon operator contributing to the\nneutral- and charged-current break-up of the deuteron. This is required for the\nextraction of solar neutrino fluxes at SNO and future neutrino experiments."
    },
    {
        "anchor": "Calculation of the neutron electric dipole moment with two dynamical\n  flavors of domain wall fermions: We present a study of the neutron electric dipole moment ($\\vec d_N$) within\nthe framework of lattice QCD with two flavors of dynamical lig ht quarks. The\ndipole moment is sensitive to the topological structure of the gaug e fields,\nand accuracy can only be achieved by using dynamical, or sea quark, calc\nulations. However, the topological charge evolves slowly in these calculations,\nle ading to a relatively large uncertainty in $\\vec d_N$. It is shown, using\nquenched configurations, that a better sampling of the charge d istribution\nreduces this problem, but because the CP even part of the fermion determinant\nis absent, both the topological charge dis tribution and $\\vec d_N$ are\npathological in the chiral limit. We discuss the statistical and systematic\nuncertainties arising from the topological charge distr ibution and unphysical\nsize of the quark mass in our calculations and prospects fo r eliminating them.\n  Our calculations employ the RBC collaboration two flavor domain wall fermion\nand DBW2 gauge action lattices with inverse lattice spacing $a^{-1}\\approx$ 1.7\nGeV, physical volume $V\\approx (2$ fm)$^3$, and light quark mass roughly equal\nto the strange quark mass ($m_{sea}=0.03 $ and 0.04). We determine a value of\nthe electric dipole moment that is zero withi n (statistical) errors, $|\\vec\nd_N| = -0.04(20)$ e-$\\theta$-fm at the smaller sea quark mass. Satisfactory\nresults for the magnetic and electric form factors of the proton and neutron\nare also obtained and presented.",
        "positive": "Non-Perturbative Regularization of 1+1D Anomaly-Free Chiral Fermions and\n  Bosons: On the equivalence of anomaly matching conditions and boundary\n  gapping rules: A non-perturbative lattice regularization of chiral fermions and bosons with\nanomaly-free symmetry $G$ in 1+1D spacetime is proposed. More precisely, we ask\n\"whether there is a local short-range quantum Hamiltonian with a finite Hilbert\nspace for a finite system realizing onsite symmetry $G$ defined on a 1D spatial\nlattice, such that its low energy physics produces a 1+1D anomaly-free chiral\nmatter theory of symmetry $G$?\" In particular, we propose that the\n3$_L$-5$_R$-4$_L$-0$_R$ U(1) chiral fermion theory, with two left-moving\nfermions of charge-3 and 4, and two right-moving fermions of charge-5 and 0 at\nlow energy, can be put on a 1D spatial lattice where the U(1) symmetry is\nrealized as an onsite symmetry, if we include properly designed multi-fermion\ninteractions with intermediate strength. In general, we propose that any 1+1D\nU(1)-anomaly-free chiral matter theory can be defined as a finite system on a\n1D lattice with onsite symmetry by using a quantum Hamiltonian with continuous\ntime, but without suffering from Nielsen-Ninomiya theorem's fermion-doubling,\nif we include properly-designed interactions between matter fields. We propose\nhow to design such interactions by looking for extra symmetries via\nbosonization/fermionization. We comment on the new ingredients and the\ndifferences of ours compared to Ginsparg-Wilson fermion, Eichten-Preskill, and\nChen-Giedt-Poppitz (CGP) models, and suggest modifying CGP model to have\nsuccessful mirror-decoupling. We show a topological non-perturbative proof of\nthe equivalence between $G$-symmetric 't Hooft anomaly cancellation conditions\nand $G$-symmetric gapping rules (e.g. Haldane's stability conditions for\nLuttinger liquid) for multi-U(1) symmetry. We expect our result holds\nuniversally regardless of spatial Hamiltonian or Lagrangian/spacetime path\nintegral formulation. Numerical tests are demanding tasks but highly desirable\nfor future work."
    },
    {
        "anchor": "Charmonium spectral functions with the variational method in zero and\n  finite temperature lattice QCD: We propose a method to evaluate spectral functions on the lattice based on a\nvariational method. On a lattice with a finite spatial extent, spectral\nfunctions consist of discrete spectra only. Adopting a variational method, we\ncalculate the locations and the heights of spectral functions at low-lying\ndiscrete spectra. We first test the method in the case of analytically solvable\nfree Wilson quarks at zero and finite temperatures and confirm that the method\nwell reproduces the analytic results for low-lying spectra. We find that we can\nsystematically improve the results by increasing the number of trial states. We\nthen apply the method to calculate the charmonium spectral functions for S and\nP-wave states at zero-temperature in quenched QCD and compare the results with\nthose obtained using the conventional maximum entropy method (MEM). The results\nfor the ground state are consistent with the location and the area of the first\npeak in spectral functions from the MEM, while the variational method leads to\na mass which is closer to the experimental value for the first excited state.\nWe also investigate the temperature dependence of the spectral functions for\nS-wave states below and above $T_c$. We obtain no clear evidences for\ndissociation of $J/\\psi$ and $\\eta_c$ up to 1.4$T_c$.",
        "positive": "$B \\to \u03c0l\\bar\u03bd$ Form Factors with NRQCD Heavy Quark and Clover\n  Light Quark Actions: We report results on semileptonic $B\\to\\pi l\\bar{\\nu}$ decay form factors\nnear $q^2_{\\rm max}$ using NRQCD heavy quark and clover light quark actions and\ncurrents improved through $O(\\alpha a)$. An inconsistency with the soft pion\nrelation $f^0(q^2_{\\rm max})= f_B/f_{\\pi}$ found in a previous work is\nconfirmed, and a possible solution with nonperturbative renormalization is\ndiscussed. We find that $f^+(q^2)$ is well described by the $B^*$ pole near\n$q^2_{\\rm max}$, and its $1/M_B$ scaling is also consistent with the prediction\nof the pole dominance model."
    },
    {
        "anchor": "Test of the Schr\u00f6dinger functional with chiral fermions in the\n  Gross-Neveu model: The recently proposed construction of chiral fermions on lattices with\nboundaries is tested in an interacting theory up to first order of perturbation\ntheory. We confirm that, in the bulk of the lattice, the chiral Ward identities\ntake their continuum value up to cutoff effects without any tuning. Universal\nquantities are defined that have an expansion in the renormalised couplings\nwith coefficients that are functions of the physical size and the periodicity\nin the spatial direction. These coefficient functions have to be identical for\ndifferent discretisations. We find agreement with the standard Wilson fermions.\nThe computation is done in the asymptotically free Gross-Neveu model with\ncontinuous chiral symmetry.",
        "positive": "Vortices and confinement in hot and cold D=2+1 gauge theories: We calculate the variation with temperature of the vortex free energy in\nD=2+1 SU(2) lattice gauge theories. We do so both above and below the\ndeconfining transition at T=Tc. We find that this quantity is zero at all T for\nlarge enough volumes. For T<Tc this observation is consistent with the fact\nthat the phase is linearly confining; while for T>Tc it is consistent with the\nconventional expectation of `spatial' linear confinement. In small spatial\nvolumes this quantity is shown to be non-zero. The way it decreases to zero\nwith increasing volume is shown to be controlled by the (spatial) string\ntension and it has the functional form one would expect if the vortices being\nstudied were responsible for the confinement at low T, and for the `spatial'\nconfinement at large T. We also discuss in detail some of the direct numerical\nevidence for a non-zero spatial string tension at high T, and we show that the\nobserved linearity of the (spatial) potential extends over distances that are\nlarge compared to typical high-T length scales."
    },
    {
        "anchor": "The measurement, fitting and interpretation of the radial distributions\n  of Heavy-Light mesons calculated on a lattice with dynamical fermions: In our earlier work, the charge and matter radial distributions of\nheavy-light mesons were measured on a 16^3 times 24 lattice with a lattice\nspacing of a = 0.17 fm and a light quark mass about that of the strange quark.\n  Several major improvements have now been made: 1) Dynamical fermions are used\nwith a approximately 0.14 fm; 2) More gauge configurations are included (78 vs\n20); 3) Off-axis, in addition to on-axis, insertions are made; 4) The data\nanalysis is much more complete. In particular, distributions involving excited\nstates are extracted.",
        "positive": "Topological susceptibility in the SU(3) random vortex world-surface\n  model: The topological charge is constructed for SU(3) center vortex world-surfaces\ncomposed of elementary squares on a hypercubic lattice. In distinction to the\nSU(2) case investigated previously, it is necessary to devise a proper\ntreatment of the color structure at vortex branchings, which arise in the SU(3)\ncase, but not for SU(2). The construction is used to evaluate the topological\nsusceptibility in the random vortex world-surface model of infrared Yang-Mills\ndynamics. Results for the topological susceptibility are reported as a function\nof temperature, including both the confined as well as the deconfined phase."
    },
    {
        "anchor": "Non-perturbative beta function in three-dimensional electrodynamics: We apply the Schrodinger functional method to the Abelian gauge theory in\nthree dimensions with Nf=2 four-component fermions. We find that the calculated\nbeta function does not cross zero in the range of coupling we study. This\nimplies that the theory exhibits confinement and mass generation, rather than a\nconformal infared regime.",
        "positive": "Dynamical Local Chirality and Chiral Symmetry Breaking: We present some of the reasoning and results substantiating the notion that\nspontaneous chiral symmetry breaking (SChSB) in QCD is encoded in local chiral\nproperties of Dirac eigenmodes. Such association is possible when viewing\nchirality as a dynamical effect, measured with respect to the benchmark of\nstatistically independent left-right components. Following this rationale leads\nto describing local chiral behavior by a taylor-made correlation, namely the\nrecently introduced correlation coefficient of polarization C_A. In this\nlanguage, correlated modes (C_A>0) show dynamical preference for local\nchirality while anti-correlated modes (C_A<0) favor anti-chirality. Our\nconclusion is that SChSB in QCD can be viewed as dominance of low-energy\ncorrelation (chirality) over anti-correlation (anti-chirality) of Dirac sea.\nThe spectral range of local chirality, chiral polarization scale Lambda_ch, is\na dynamically generated scale in the theory associated with SChSB. One\nimplication of these findings is briefly discussed."
    },
    {
        "anchor": "Holography on tessellations of hyperbolic space: We compute boundary correlation functions for scalar fields on tessellations\nof two- and three-dimensional hyperbolic geometries. We present evidence that\nthe continuum relation between the scalar bulk mass and the scaling dimension\nassociated with boundary-to-boundary correlation functions survives the\ntruncation of approximating the continuum hyperbolic space with a lattice.",
        "positive": "Scale hierarchy in high-temperature QCD: Because of asymptotic freedom, QCD becomes weakly interacting at high\ntemperature: this is the reason for the transition to a deconfined phase in\nYang-Mills theory at temperature $T_c$. At high temperature $T \\gg T_c$, the\nsmallness of the running coupling $g$ induces a hierachy betwen the \"hard\",\n\"soft\" and \"ultrasoft\" energy scales $T$, $g T$ and $g^2 T$. This hierarchy\nallows for a very successful effective treatment where the \"hard\" and the\n\"soft\" modes are successively integrated out. However, it is not clear how high\na temperature is necessary to achieve such a scale hierarchy.\n  By numerical simulations, we show that the required temperatures are\nextremely high. Thus, the quantitative success of the effective theory down to\ntemperatures of a few $T_c$ appears surprising a posteriori."
    },
    {
        "anchor": "Properties of the twisted Polyakov loop coupling and the infrared fixed\n  point in the SU(3) gauge theories: We report the nonperturbative behavior of the twisted Polyakov loop (TPL)\ncoupling constant for the SU(3) gauge theories defined by the ratio of Polyakov\nloop correlators in finite volume with twisted boundary condition. We reveal\nthe vacuum structures and the phase structure for the lattice gauge theory with\nthe twisted boundary condition. Carrying out the numerical simulations, we\ndetermine the nonperturbative running coupling constant in this renormalization\nscheme for the quenched QCD and Nf=12 SU(3) gauge theories. At first, we study\nthe quenched QCD theory using the plaquette gauge action. The TPL coupling\nconstant has a fake fixed point in the confinement phase. We discuss this fake\nfixed point of the TPL scheme and obtain the nonperturbative running coupling\nconstant in the deconfinement phase, where the magnitude of the Polyakov loop\nshows the nonzero values. We also investigate the system coupled to fundamental\nfermions. Since we use the naive staggered fermion with the twisted boundary\ncondition in our simulation, only multiples of 12 are allowed for the number of\nflavors. According to the perturbative two loop analysis, the Nf=12 SU(3) gauge\ntheory might have a conformal fixed point in the infrared region. However, the\nrecent lattice studies show controversial results for the existence of the\nfixed point. We point out possible problems in previous works, and present our\ncareful study. Finally, we find the infrared fixed point (IRFP) and discuss the\nrobustness of the nontrivial IRFP of many flavor system under the change of the\nanalysis method. A part of preliminary results was reported in the proceedings\n[1, 2] and the letter paper [3]. In this paper we include a review of these\nresults and give a final conclusion for the existence of IRFP of SU(3) Nf = 12\nmassless theory using the updated data.",
        "positive": "Light Quarks, Zero Modes, and Exceptional Configurations: In continuum QCD, nontrivial gauge topologies give rise to zero eigenvalues\nof the massless Dirac operator. In lattice QCD with Wilson fermions, these zero\nmodes appear as exactly real eigenvalues of the Wilson-Dirac operator and hence\nas poles in the quark propagator in the vicinity of critical hopping parameter.\nIt is shown that \"exceptional configurations\" which arise in the quenched\napproximation at small quark mass are the result of the fluctuation of the\nposition of zero mode poles to sub-critical values of the hopping parameter on\nparticular gauge configurations. We describe a procedure for correcting these\nlattice artifacts by first isolating the contribution of zero mode poles to the\nquark propagator and then shifting the sub-critical poles to the critical\npoint. This procedure defines a modified quenched approximation in which\naccurate calculations can be carried out for arbitrarily small quark masses."
    },
    {
        "anchor": "LeapfrogLayers: A Trainable Framework for Effective Topological Sampling: We introduce LeapfrogLayers, an invertible neural network architecture that\ncan be trained to efficiently sample the topology of a 2D $U(1)$ lattice gauge\ntheory. We show an improvement in the integrated autocorrelation time of the\ntopological charge when compared with traditional HMC, and look at how\ndifferent quantities transform under our model. Our implementation is open\nsource, and is publicly available on github at\nhttps://github.com/saforem2/l2hmc-qcd.",
        "positive": "Leading Quenching Effects in the Proton Magnetic Moment: We present the first investigation of the extrapolation of quenched nucleon\nmagnetic moments in quenched chiral effective field theory. We utilize\nestablished techniques in finite-range regularisation and compare with standard\ndimensional regularisation methods. Finite-volume corrections to the relevant\nloop integrals are also addressed. Finally, the contributions of dynamical sea\nquarks to the proton moment are estimated using a recently discovered\nphenomenological link between quenched and physical QCD."
    },
    {
        "anchor": "Form factors in the $\\mathrm{B}_\\mathrm{s} \\rightarrow \\mathrm{K} \\ell\n  \u03bd$ decays using HQET and the lattice: We report on a recent computation of the form factors in semi-leptonic decays\nof the $\\mathrm{B}_\\mathrm{s}$ using Heavy Quark Effective Theory (HQET)\nformalism applied on the lattice. The connection of the form factors with the\n2-point and 3-point correlators on the lattice is explained, and the subsequent\nnon-perturbative renormalization of HQET and it's matching to $N_f=2$ QCD is\noutlined. The results of the (static) leading-order calculation in the\ncontinuum limit is presented.",
        "positive": "Nucleon generalized form factors and sigma term from lattice QCD near\n  the physical quark mass: We present new N_f=2 data for the nucleon generalized form factors, varying\nvolume, lattice spacing and pion mass, down to 150 MeV. We also give an update\nof our direct calculation of the nucleon sigma term for a range of pion mass\nvalues including the lightest one."
    },
    {
        "anchor": "Weak hamiltonian Wilson Coefficients from Lattice QCD: In this work we present a calculation of the Wilson Coefficients $C_1$ and\n$C_2$ of the Effective Weak Hamiltonian to all-orders in $\\alpha_s$, using\nlattice simulations. Given the current availability of lattice spacings we\nrestrict our calculation to unphysically light $W$ bosons around 2 GeV and we\nstudy the systematic uncertainties of the two Wilson Coefficients.",
        "positive": "Representations of Fermionic Correlators at Finite Temperatures: The symmetry group of the staggered Fermion transfer matrix in a spatial\ndirection is constructed at finite temperature. Hadron-like operators carrying\nirreducible representations of this group are written down from the breaking of\nthe zero temperature group. Analysis of the correlators in a free fermion\ntheory suggests new measurements which can test current interpretations."
    },
    {
        "anchor": "Compact Gauge Fields for Supersymmetric Lattices: We show that a large class of Euclidean extended supersymmetric lattice gauge\ntheories constructed in [hep-lat/0302017 - hep-lat/0503039] can be regarded as\ncompact formulations by using the polar decomposition of the complex link\nfields. In particular, the gauge part of the supersymmetric lattice action is\nthe standard Wilson action. This formulation facilitates the construction of\ngauge invariant operators.",
        "positive": "A comparative study of overlap and staggered fermions in the Schwinger\n  model: We investigate the validity of the square rooting procedure of the staggered\ndeterminant in the context of the Schwinger model. We find some evidence that\nat fixed physical quark mass the square root of the staggered determinant\nbecomes proportional to the overlap determinant in the continuum limit. We also\nfind that at fixed lattice spacing moderate smearing dramatically improves the\nchiral behavior of staggered fermions."
    },
    {
        "anchor": "Study of the systematic errors in the calculation of renormalization\n  constants of the topological susceptibility on the lattice: We present a study of the systematic effects in the nonperturbative\nevaluation of the renormalization constants which appear in the\nfield-theoretical determination of the topological susceptibility in pure\nYang-Mills theory. The study is performed by computing the renormalization\nconstants on configurations that have been calibrated by use of the\nGinsparg-Wilson formalism and by cooling.",
        "positive": "The neutron-proton mass difference: We present a lattice calculation of the mass difference between neutron and\nproton, for which we find $ M_n - M_p = 1.73(69) \\, \\text{MeV}$. This is\nobtained at 1st order in the $QED$ coupling $\\alpha_{EM}$ and in the mass\ndifference between $u$ and $d$ quarks $\\frac{m_d-m_u}{\\Lambda_{QCD}}$. We adopt\na purely hadronic scheme to renormalize the theory and provide a prescription\nto separate the $QED$ and strong $IB$ contributions. The simulation is carried\nout using the ETMC gauge configurations with $N_f=2+1+1$ dynamical quarks. We\nextrapolate among $3$ values of the lattice spacing and pion masses in the\nrange $M_\\pi \\simeq 200 - 450 $ MeV."
    },
    {
        "anchor": "Chiral Perturbation for Large Momentum Effective Field Theory: Large momentum effective field theory (LaMET) enables the extraction of\nparton distribution functions (PDFs) directly on a Euclidean lattice through a\nfactorization theorem that relates the computed quasi-PDFs to PDFs. We apply\nchiral perturbation theory (ChPT) to LaMET to further separate soft scales,\nsuch as light quark masses and lattice size, to obtain leading model\nindependent extrapolation formulas for extrapolations to physical quark masses\nand infinite volume. We find that the finite volume effect is reduced when the\nnucleon carries a finite momentum. For nucleon momentum greater than $1$ GeV\nand the lattice size $L$ and pion mass $ m_\\pi $ satisfying $m_\\pi L\\geq 3$,\nthe finite volume effect is less than $1\\%$ and is negligible for the current\nprecision of lattice computations. This can be interpreted as a Lorentz\ncontraction of the nucleon size in the $z$-direction which makes the lattice\nsize effectively larger in that direction. We also find that the quark mass\ndependence in the infinite volume limit computed with non-zero nucleon momentum\nreproduces the previous result computed at zero momentum, as expected. Our\napproach can be generalized to other parton observables in LaMET straight\nforwardly.",
        "positive": "Convergence issues in ChPT: a lattice perspective: This review addresses the practical convergence of the ChPT series in the\np-regime. In the SU(2) framework there is a number of new results, and improved\nestimates of \\bar\\ell_3 and \\bar\\ell_4 are available. In the SU(3) framework\nfew new lattice computations have appeared and the improvement in the precision\nof the low-energy constants L_i is comparatively slow. I sketch some of the\nconvergence issues genuine to extensions of ChPT which include additional\nsources of chiral symmetry breaking (finite lattice spacing) and/or violations\nof unitarity (different sea and valence quark masses). Finally, it is pointed\nout that the quark mass ratios m_u/m_d, m_s/m_d happen to be such that no\nreordering of the chiral series is needed to accommodate the experimental pion\nand kaon masses."
    },
    {
        "anchor": "Ginsparg-Wilson-Luscher Symmetry and Ultralocality: Important recent discoveries suggest that Ginsparg-Wilson-Luscher (GWL)\nsymmetry has analogous dynamical consequences for the theory on the lattice as\nchiral symmetry does in the continuum. While it is well known that inherent\nproperty of lattice chiral symmetry is fermion doubling, we show here that\ninherent property of GWL symmetry is that the infinitesimal symmetry\ntransformation couples fermionic degrees of freedom at arbitrarily large\nlattice distances (non-ultralocality). The consequences of this result for\nultralocality of symmetric actions are discussed.",
        "positive": "Finite volume treatment of $\u03c0\u03c0$ scattering in the $\u03c1$ channel: We make a theoretical study of $\\pi\\pi$ scattering with quantum numbers\n$J^{PC}=1^{--}$ in a finite box. To calculate physical observables for infinite\nvolume from lattice QCD, the finite box dependence of the potentials is not\nusually considered. We quantify such effects by means of two different\napproaches for vector-isovector $\\pi\\pi$ scattering based on Unitarized Chiral\nPerturbation Theory results: the Inverse Amplitude Method and another one based\non the $N/D$ method. We take into account finite box effects stemming from\nhigher orders through loops in the crossed $t,u-$channels as well as from the\nrenormalization of the coupling constants. The main conclusion is that for\n$\\pi\\pi$ phase shifts in the isovector channel one can safely apply L\\\"uscher\nbased methods for finite box sizes of $L$ greater than $2 m_\\pi^{-1}$."
    },
    {
        "anchor": "The APENEXT project: APENEXT is a new generation APE processor, optimized for LGT simulations. The\nproject follows the basic ideas of previous APE machines and develops simple\nand cheap parallel systems with multi T-Flops processing power. This paper\ndescribes the main features of this new development.",
        "positive": "Results from lattice simulations of N=4 supersymmetric Yang--Mills: We report recent results and developments from our ongoing lattice studies of\n$\\mathcal N = 4$ supersymmetric Yang--Mills theory. These include a proof that\nonly a single fine-tuning needs to be performed, so long as the moduli space is\nnot lifted by nonperturbative effects. We extend our investigations of\nsupersymmetry restoration in the continuum limit by initiating Monte Carlo\nrenormalization group studies. We present additional numerical evidence that\nthe lattice theory does not suffer from a sign problem. Finally we study the\nstatic potential, which we find to be Coulombic at both weak and strong\ncoupling. We compare the static potential Coulomb coefficients to perturbation\ntheory, including initial results for N=3 colors in addition to N=2."
    },
    {
        "anchor": "Rotational Symmetry and A Light Mode in Two-Dimensional Staggered\n  Fermions: To obtain a light mode in two-dimensional staggered fermions, we introduce\nfour new local operators keeping the rotational invariance for a staggered\nDirac operator. To split masses of tastes, three cases are considered. The mass\nmatrix and the propagator for free theories are analyzed. We find that one of\nthree cases is a good candidate for taking a single mode by the mass splitting.\nIn the case, it is possible that a heavy mode obtains infinite mass on even\nsites or odd sites.",
        "positive": "Freeze-out parameters from continuum extrapolated lattice data: We present continuum extrapolated lattice results for the higher order\nfluctuations of conserved charges in high temperature Quantum Chromodynamics.\nThrough the matching of the grand canonical ensemble on the lattice to the net\ncharge and net baryon distribution realized in heavy ion experiments the\ntemperature and the chemical potential may be estimated at the time of chemical\nfreeze-out"
    },
    {
        "anchor": "Heatbath Noise Methods in Lattice QCD: In a recent paper, de Forcrand has pointed out that matrix inversions using\nGaussian noise need not be iterated to full convergence, but instead may be\nsolved approximately and treated as a heatbath. Gaussian noise however is not\noptimal for minimizing variance. It shown here how his algorithm may be\ngeneralized to a mixture of Gaussian and Z(N) noise, resulting in a smaller\neffective variance for some operators.",
        "positive": "B_s Mesons using Staggered Light Quarks: Last year we proposed using staggered fermions as the light quarks, combined\nwith nonrelativistic heavy quarks, in simulations of heavy-light mesons. A\nfirst round of tests which focuses on the B_s meson has been completed using\nquenched lattices, and results are presented here for the kinetic B_s mass, the\nB_s^* - B_s splitting, and f_{B_s}. The next project, already underway, is to\ncompute the B and B_s decay constants and spectra on the n_f = 2+1 and 3 MILC\nlattices. We report on progress with one set of these configurations."
    },
    {
        "anchor": "The absence of cut--off effects for the fixed point action in 1--loop\n  perturbation theory: In order to support the formal renormalization group arguments that the fixed\npoint action of an asymptotically free model gives cut--off independent\nphysical predictions in 1--loop perturbation theory, we calculate the finite\nvolume mass--gap $m(L)$ in the non--linear $\\sigma$--model. No cut--off effect\nof the type $g^4\\left(a/L\\right)^n$ is seen for any $n$. The results are\ncompared with those of the standard and tree level improved Symanzik actions.",
        "positive": "Proton and neutron electromagnetic radii and magnetic moments from $N_f\n  = 2 + 1$ lattice QCD: We present results for the electromagnetic form factors of the proton and\nneutron computed on the $(2 + 1)$-flavor Coordinated Lattice Simulations (CLS)\nensembles including both quark-connected and -disconnected contributions. The\n$Q^2$-, pion-mass, lattice-spacing, and finite-volume dependence of our form\nfactor data is fitted simultaneously to the expressions resulting from\ncovariant chiral perturbation theory including vector mesons amended by models\nfor lattice artefacts. From these fits, we determine the electric and magnetic\nradii and the magnetic moments of the proton and neutron, as well as the Zemach\nradius of the proton. To assess the influence of systematic effects, we average\nover various cuts in the pion mass and the momentum transfer, as well as over\ndifferent models for the lattice-spacing and finite-volume dependence, using\nweights derived from the Akaike Information Criterion (AIC). Our results for\nthe magnetic moments of the proton and neutron are in good agreement with the\nexperimental values and have a relative precision of about $2.4\\,\\%$ and\n$3.7\\,\\%$, respectively. For the electromagnetic radii of the proton, we\nachieve a precision at the $1.5\\,\\%$ level."
    },
    {
        "anchor": "Equivariance and generalization in neural networks: The crucial role played by the underlying symmetries of high energy physics\nand lattice field theories calls for the implementation of such symmetries in\nthe neural network architectures that are applied to the physical system under\nconsideration. In these proceedings, we focus on the consequences of\nincorporating translational equivariance among the network properties,\nparticularly in terms of performance and generalization. The benefits of\nequivariant networks are exemplified by studying a complex scalar field theory,\non which various regression and classification tasks are examined. For a\nmeaningful comparison, promising equivariant and non-equivariant architectures\nare identified by means of a systematic search. The results indicate that in\nmost of the tasks our best equivariant architectures can perform and generalize\nsignificantly better than their non-equivariant counterparts, which applies not\nonly to physical parameters beyond those represented in the training set, but\nalso to different lattice sizes.",
        "positive": "Spatial diquark correlations in a hadron: Using lattice QCD, a diquark can be studied in a gauge-invariant manner by\nbinding it to a static quark in a heavy-light-light hadron. We compute the\nsimultaneous two-quark density of a diquark, including corrections for periodic\nboundary conditions. We define a correlation function to isolate the intrinsic\ncorrelations of the diquark and reduce the effects caused by the presence of\nthe static quark. Away from the immediate vicinity of the static quark, the\ndiquark has a consistent shape, with much stronger correlations seen in the\ngood (scalar) diquark than in the bad (vector) diquark. We present results for\nm_{\\pi}=293 MeV in N_f=2+1 QCD as well as m_{\\pi}=940 MeV in quenched QCD, and\ndiscuss the dependence of the spatial size on the pion mass."
    },
    {
        "anchor": "Lattice analysis of semi-leptonic form factors: We present preliminary results from simulations done on 170 $32^3 \\times 64$\nlattices at $\\beta = 6.0$ using quenched Wilson fermions. This talk focuses on\nthe $Q^2$ behavior of the form-factors, extrapolation in quark masses,\ndependence on renormalization scheme, and comparison with heavy-quark effective\ntheory (HQET). Even though we cannot estimate errors due to quenching and\ndiscretization, our results are consistent with experimental results for $D$\ndecays. We present results for the Isgur-Wise function and estimate $\\xi'(w=1)\n= 0.97(6)$.",
        "positive": "\u03b7 and \u03b7' masses and decay constants from lattice QCD with\n  2+1+1 quark flavours: We investigate the masses and decay constants of eta and eta' mesons using\nthe Wilson twisted mass formulation with N_f=2+1+1 dynamical quark flavours\nbased on gauge configurations of ETMC. We show how to efficiently subtract\nexcited state contributions to the relevant correlation functions and estimate\nin particular the eta' mass with improved precision. After investigating the\nstrange quark mass dependence and the continuum and chiral extrapolations, we\npresent our results for masses and mixing angle(s) at the physical point. Using\nchiral perturbation theory we also extract the decay constants f_l and f_s and\nuse them to estimate the decay widths of eta,\\eta' to gamma gamma and the\ntransition form factor in the limit of large momentum transfer."
    },
    {
        "anchor": "On the particle spectrum and the conformal window: We study the SU(3) gauge theory with twelve flavours of fermions in the\nfundamental representation as a prototype of non-Abelian gauge theories inside\nthe conformal window. Guided by the pattern of underlying symmetries, chiral\nand conformal, we analyze the two-point functions theoretically and on the\nlattice, and determine the finite size scaling and the infinite volume fermion\nmass dependence of the would-be hadron masses. We show that the spectrum in the\nCoulomb phase of the system can be described in the context of a universal\nscaling analysis and we provide the nonperturbative determination of the\nfermion mass anomalous dimension gamma*=0.235(46) at the infrared fixed point.\nWe comment on the agreement with the four-loop perturbative prediction for this\nquantity and we provide a unified description of all existing lattice results\nfor the spectrum of this system, them being in the Coulomb phase or the\nasymptotically free phase. Our results corroborate the view that the fixed\npoint we are studying is not associated to a physical singularity along the\nbare coupling line and estimates of physical observables can be attempted on\neither side of the fixed point. Finally, we observe the restoration of the U(1)\naxial symmetry in the two-point functions.",
        "positive": "$J/\u03c8$ -nucleon scattering in $P_{c}^{+}$ pentaquarks channel: Two pentaquarks $P_{c}^{+}$ were discovered by LHCb collaboration as peaks in\nthe proton-$J/\\psi$ invariant mass. We perform the lattice QCD study of the\nscattering between $J/\\psi$ meson and nucleon in the channels with\n$J^{P}=\\frac{3}{2}^{+},\\frac{3}{2}^{-}, \\frac{5}{2}^{+}, \\frac{5}{2}^{-}$,\nwhere $P_{c}^{+}$ was discovered. This is the first lattice simulation that\nreaches the energies $4.3-4.5~$GeV where pentaquarks reside. The higher partial\nwaves $L>0$ are also explored for the first time. In this study we consider the\nsingle-channel approximation for scattering of $NJ/\\psi$. Energies and\neigenstates are extracted for the $NJ/\\psi$ system at the zero total momentum\nfor all six irreducible representations of the lattice irreducible\nrepresentation. No significant energy shifts are observed. The number of\neigenstates agrees with the number expected from non-interacting limit for\nscattering. This could possibly indicate that the $P_{c}$ resonances seen in\nexperiment are a consequence of a coupling of the $NJ/\\psi$ channel with other\ntwo-hadron channels."
    },
    {
        "anchor": "The twisted Polyakov loop coupling and the search for an IR fixed point: We report the nonperturbative behavior of the twisted Polyakov loop (TPL)\ncoupling constant for the SU(3) gauge theories defined by the ratio of Polyakov\nloop correlators in finite volume with twisted boundary condition. Carrying out\nthe numerical simulations, we determine the nonperturbative running coupling\nconstant in this renormalization scheme for Nf=12 SU(3) gauge theory.\n  According to the perturbative two loop analysis, the Nf=12 SU(3) gauge theory\nmight have a conformal fixed point in the infrared region. However, the recent\nlattice studies show controversial results for the existence of the fixed\npoint. We point out possible reasons of the controversy in previous works, and\npresent our careful study. Finally, we find the infrared fixed point (IRFP) and\ndiscuss the robustness of the nontrivial IRFP of many flavor system under the\nchange of the analysis method. This talk is based on the paper[1].",
        "positive": "Dyon structures in the deconfinement phase of lattice gluodynamics:\n  topological clusters, holonomies and Abelian monopoles: The topological structure of lattice gluodynamics is studied at intermediate\nresolution scale in the deconfining phase with the help of a cluster analysis.\nUV filtered topological charge densities are determined from a fixed number of\nlow-lying eigenmodes of the overlap Dirac operator with three types of temporal\nboundary conditions applied to the valence quark fields. This method usually\nallows to find all three distinguished (anti)dyon constituents in the gauge\nfield of Kraan-van Baal-Lee-Lu (anti)caloron solutions. The clustering of the\nthree topological charge densities in Monte Carlo generated configurations is\nthen used to mark the positions of anticipated (anti)dyons of the corresponding\ntype. In order to support this interpretation, inside these clusters, we search\nalso for time-like Abelian monopole currents (defined in the maximally Abelian\ngauge) as well as for local holonomies with at least two approximately\ndegenerated eigenvalues. Our results support the view that light dyon-antidyon\npairs - in contrast to the heavy (anti)caloron dyon constituents - contribute\ndominantly to thermal Yang-Mills fields in the deconfinement phase. This paper\nis dedicated to the memory of Pierre van Baal and Dmitri Igorevich Diakonov who\nhave influenced our work very much."
    },
    {
        "anchor": "The thermal QCD transition with two flavours of twisted mass fermions: We investigate the thermal QCD transition with two flavors of maximally\ntwisted mass fermions for a set of pion masses, 300 MeV \\textless $m_\\pi$\n\\textless 500 MeV, and lattice spacings $a$ \\textless 0.09 fm. We determine the\npseudo-critical temperatures and discuss their extrapolation to the chiral\nlimit using scaling forms for different universality classes, as well as the\nscaling form for the magnetic equation of state. For all pion masses considered\nwe find resonable consistency with O(4) scaling plus leading corrections.\nHowever, a true distinction between the O(4) scenario and a first order\nscenario in the chiral limit requires lighter pions than are currently in use\nin simulations of Wilson fermions.",
        "positive": "Toward Group Theory Operators for tmLQCD Hadrons: Extraction of the mass spectrum from twisted mass lattice QCD is facilitated\nby respecting the octahedral group of rotations and accommodating the broken\nparity and flavor symmetries of the theory. In this work, group theory meson\noperators adapted to these constraints are constructed for the special case of\nquark and antiquark fields at a common lattice site, connected by extended\ngauge field paths."
    },
    {
        "anchor": "The finite temperature QCD phase transition with domain wall fermions: The domain wall formulation of lattice fermions is expected to support\naccurate chiral symmetry, even at finite lattice spacing. Here we attempt to\nuse this new fermion formulation to simulate two-flavor, finite temperature QCD\nnear the chiral phase transition. In this initial study, a variety of quark\nmasses, domain wall heights and domain wall separations are explored using an\n8^3 x 4 lattice. Both the expectation value of the Wilson line and the chiral\ncondensate show the temperature dependence expected for the QCD phase\ntransition. Further, the desired chiral properties are seen for the chiral\ncondensate, suggesting that the domain wall fermion formulation may be an\neffective approach for the numerical study of QCD at finite temperature.",
        "positive": "Approaching the Bottom Using Fine Lattices With Domain-Wall Fermions: We explore the heavy-quark mass region above the charm mass using M\\\"obius\ndomain-wall fermions on fine lattices at $a = 0.080$, $0.055$, and $0.044$ fm.\nWe examine masses and decay constants using a series of heavy quark masses up\nto 3 times the charm quark. We analyze the cutoff effects for heavy quarks\nabove the charm and account for the leading order discretization effects using\nideas from HQET. We extrapolate to the bottom quark mass and report preliminary\nresults for $f_{B}$ and $f_{B_s}$"
    },
    {
        "anchor": "Spontaneous symmetry breaking induced by complex fermion determinant ---\n  yet another success of the complex Langevin method: In many interesting systems, the fermion determinant becomes complex and its\nphase plays a crucial role in the determination of the vacuum. For instance, in\nfinite density QCD at low temperature and high density, exotic fermion\ncondensates are conjectured to form due to such effects. When one applies the\ncomplex Langevin method to such a complex action system naively, one cannot\nobtain the correct results because of the singular-drift problem associated\nwith the appearance of small eigenvalues of the Dirac operator. Here we propose\nto avoid this problem by adding a fermion bilinear term to the action and\nextrapolating its coefficient to zero. We test this idea in an SO(4)-invariant\nmatrix model with a Gaussian action and a complex fermion determinant, whose\nphase is expected to induce the spontaneous breaking of the SO(4) symmetry. Our\nresults agree well with the previous results obtained by the Gaussian expansion\nmethod.",
        "positive": "Chiral susceptibility and axial U(1) anomaly near the (pseudo-)critical\n  temperature: We investigate relations between the chiral susceptibility and axial $U(1)$\nanomaly in lattice QCD at high temperatures. Employing the exactly chiral\nsymmetric Dirac operator, we separate the purely axial $U(1)$ breaking effect\nin the connected and disconnected chiral susceptibilites in a theoretically\nclean manner. Preliminary results for two-flavor lattice QCD near the critical\ntemperature are presented."
    },
    {
        "anchor": "Some remarks on O(a) improved twisted mass QCD: Twisted mass QCD (tmQCD) has been introduced as a solution to the problem of\nunphysical fermion zero modes in lattice QCD with quarks of the Wilson type. We\nhere argue that O(a) improvement of the tmQCD action and simple quark bilinear\noperators can be more economical than in the standard framework. In particular,\nan improved and renormalized estimator of the pion decay constant in\ntwo-flavour QCD is available, given only the Sheikholeslami-Wohlert coefficient\nc_sw and an estimate of the critical mass m_c.",
        "positive": "Two Loop Computation of the Schroedinger Functional in Lattice QCD: We compute the Schroedinger functional (SF) for the case of lattice QCD with\nWilson fermions (with and without SW improvement) at two-loop order in lattice\nperturbation theory. This allows us to extract the three-loop beta-function in\nthe SF-scheme. These results are required to compute the running coupling, the\nLambda-parameter and quark masses by finite size techniques with negligible\nsystematic errors. In addition our results enable the implementation of\ntwo-loop O(a) improvement in SF-simulations."
    },
    {
        "anchor": "Numerical study of O(a) improved Wilson quark action on anisotropic\n  lattice: The $O(a)$ improved Wilson quark action on the anisotropic lattice is\ninvestigated. We carry out numerical simulations in the quenched approximation\nat three values of lattice spacing ($a_{\\sigma}^{-1}=1$--2 GeV) with the\nanisotropy $\\xi=a_{\\sigma}/a_{\\tau}=4$, where $a_{\\sigma}$ and $a_{\\tau}$ are\nthe spatial and the temporal lattice spacings, respectively. The bare\nanisotropy $\\gamma_F$ in the quark field action is numerically tuned by the\ndispersion relation of mesons so that the renormalized fermionic anisotropy\ncoincides with that of gauge field. This calibration of bare anisotropy is\nperformed to the level of 1 % statistical accuracy in the quark mass region\nbelow the charm quark mass. The systematic uncertainty in the calibration is\nestimated by comparing the results from different types of dispersion\nrelations, which results in 3 % on our coarsest lattice and tends to vanish in\nthe continuum limit. In the chiral limit, there is an additional systematic\nuncertainty of 1 % from the chiral extrapolation.\n  Taking the central value $\\gamma_F=\\gamma_F^*$ from the result of the\ncalibration, we compute the light hadron spectrum. Our hadron spectrum is\nconsistent with the result by UKQCD Collaboration on the isotropic lattice. We\nalso study the response of the hadron spectrum to the change of anisotropic\nparameter, $\\gamma_F \\to \\gamma_F^* + \\delta\\gamma_F$. We find that the change\nof $\\gamma_F$ by 2 % induces a change of 1 % in the spectrum for physical quark\nmasses. Thus the systematic uncertainty on the anisotropic lattice, as well as\nthe statistical one, is under control.",
        "positive": "Topological structures and phases in U(1) gauge theory: We show that topological properties of minimal Dirac sheets as well as of\ncurrents lines characterize the phases unambiguously. We obtain the minimal\nsheets reliably by a suitable simulated-annealing procedure."
    },
    {
        "anchor": "SU(N) gauge theories in 2+1 dimensions -- further results: We calculate the string tension and part of the mass spectrum of SU(4) and\nSU(6) gauge theories in 2+1 dimensions using lattice techniques. We combine\nthese new results with older results for N=2,...,5 so as to obtain more\naccurate extrapolations to N=infinity. The qualitative conclusions of the\nearlier work are unchanged: SU(N) theories in 2+1 dimensions are linearly\nconfining as N->infinity; the limit is achieved by keeping g.g.N fixed; SU(3),\nand even SU(2), are `close' to SU(infinity). We obtain more convincing evidence\nthan before that the leading large-N correction is O(1/N.N). We look for the\nmultiplication of states that one expects in simple flux loop models of\nglueballs, but find no evidence for this.",
        "positive": "The Gradient Flow Coupling in Minimal Walking Technicolor: We present a measurement of the running coupling in SU(2) with two adjoint\nfermions in the Yang-Mills gradient flow scheme. The simulations are performed\nwith Schr\\\"odinger Functional boundary conditions using an improved HEX-smeared\nWilson fermion action. We obtain a step scaling function by defining the\ncoupling at a scale relative to the finite size of the lattice. We find a\ncontinuum limit with a non-trivial infrared fixed point."
    },
    {
        "anchor": "Resummed lattice QCD equation of state at finite baryon density:\n  strangeness neutrality and beyond: We calculate a resummed equation of state with lattice QCD simulations at\nimaginary chemical potentials. This work presents a generalization of the\nscheme introduced in 2102.06660 to the case of non-zero $\\mu_S$, focusing on\nthe line of strangeness neutrality. We present results up to $\\mu_B/T \\leq 3.5$\non the strangeness neutral line $\\left\\langle S \\right\\rangle = 0$ in the\ntemperature range $130 \\rm{MeV} \\leq T \\leq 280 \\rm{MeV}$. We also extrapolate\nthe finite baryon density equation of state to small non-zero values of the\nstrangeness-to-baryon ratio $R=\\left\\langle S \\right\\rangle / \\left\\langle B\n\\right\\rangle$. We perform a continuum extrapolation using lattice simulations\nof the 4stout-improved staggered action with 8, 10, 12 and 16 timeslices.",
        "positive": "Simulation of Supersymmetric Models with a Local Nicolai Map: We study the numerical simulation of supersymmetric models having a local\nNicolai map. The mapping can be regarded as a stochastic equation and its\nnumerical integration provides an algorithm for the simulation of the original\nmodel. In this paper, the method is discussed in details and applied to\nexamples in 0+1 and 1+1 dimensions."
    },
    {
        "anchor": "Lattice study of static quark-antiquark interactions in dense quark\n  matter: In this paper we study the interactions among a static quark-antiquark pair\nin the presence of dense two-color quark matter with lattice simulation. To\nthis end we compute Polyakov line correlation functions and determine the\nrenormalized color averaged, color singlet and color triplet grand potentials.\nThe color singlet grand potential allows us to elucidate the number of quarks\ninduced by a static quark antiquark source, as well as the internal energy of\nsuch a pair in dense quark matter. We furthermore determine the screening\nlength, which in the confinement phase is synonymous with the string breaking\ndistance. The screening length is a decreasing function of baryon density, due\nto the possibility to break the interquark string via a scalar diquark\ncondensate at high density. We also study the large distance properties of the\ncolor singlet grand potential in a dense medium and find that it is well\ndescribed by a simple Debye screening formula, parameterized by a Debye mass\nand an effective coupling constant. The latter is of order of unity, i.e. even\nat large density two-color quark matter is a strongly correlated system.",
        "positive": "The Hyperfine Splitting in Charmonium: Lattice Computations Using the\n  Wilson and Clover Fermion Actions: We compute the hyperfine splitting $m_{J/\\psi}-m_{\\eta_c}$ on the lattice,\nusing both the Wilson and $O(a)$-improved (clover) actions for quenched quarks.\nThe computations are performed on a $24^3\\times48$ lattice at $\\beta = 6.2$,\nusing the same set of 18 gluon configurations for both fermion actions. We find\nthat the splitting is 1.83\\err{13}{15} times larger with the clover action than\nwith the Wilson action, demonstrating the sensitivity of the spin-splitting to\nthe magnetic moment term which is present in the clover action. However, even\nwith the clover action the result is less than half of the physical\nmass-splitting. We also compute the decay constants $f_{\\eta_c}$ and\n$f^{-1}_{J/\\psi}$, both of which are considerably larger when computed using\nthe clover action than with the Wilson action. For example for the ratio\n$f^{-1}_{J/\\psi}/f^{-1}_{\\rho}$ we find 0.32\\err{1}{2} with the Wilson action\nand $0.48\\pm 3$ with the clover action (the physical value is 0.44(2))."
    },
    {
        "anchor": "Controlling One-Dimensional Langevin Dynamics on the Lattice: Stochastic evolutions of classical field theories have recently become\npopular in the study of problems such as determination of the rates of\ntopological transitions and the statistical mechanics of nonlinear coherent\nstructures. To obtain high precision results from numerical calculations, a\ncareful accounting of spacetime discreteness effects is essential, as well as\nthe development of schemes to systematically improve convergence to the\ncontinuum. With a kink-bearing $\\phi^4$ field theory as the application arena,\nwe present such an analysis for a 1+1-dimensional Langevin system. Analytical\npredictions and results from high resolution numerical solutions are found to\nbe in excellent agreement.",
        "positive": "The density of state method for first-order phase transitions in\n  Yang-Mills theories: Lattice Field Theory can be used to study finite temperature first-order\nphase transitions in new, strongly-coupled gauge theories of phenomenological\ninterest. Metastable dynamics arising in proximity of the phase transition can\nlead to large, uncontrolled numerical errors when analysed with standard\nmethods. In this contribution, we discuss a prototype lattice calculation in\nwhich the first-order deconfinement transition in the strong Yang-Mills sector\nof the standard model is analysed using a novel lattice method, the logarithmic\nlinear relaxation algorithm. This method provides a determination of the\ndensity of states of the system with exponential error suppression."
    },
    {
        "anchor": "$K$- and $D_{(s)}$-meson leptonic decay constants with physical light,\n  strange and charm quarks by ETMC: We present a lattice QCD computation and preliminary results for the leptonic\ndecay constants of the pseudoscalar mesons $K$, $D$ and $D_{s}$ in the\nisosymmetric QCD limit. The computation is based on simulations of $N_f =\n2+1+1$ dynamical quarks performed by the Extended Twisted Mass Collaboration\n(ETMC), where the light, strange and charm quark masses are all tuned at their\nphysical values. We also present preliminary unitarity checks for the first and\nsecond rows of the Cabibbo-Kobayashi-Maskawa matrix.",
        "positive": "(Dimensional) twisted reduction in large N gauge theories: We show that the spontaneous breaking of center symmetry can be avoided on a\n$L^2\\times 1^2$ lattice with the appropriate choice of twisted boundary\nconditions. In order for this to work it is crucial that the twisted boundary\nconditions are chosen in the reduced plane. This suggests that the choice of\ntwist tensor can influence the directions in which color and space degrees of\nfreedom become indistinguishable. We also present some preliminary quantitative\ndata comparing the value of the plaquette for different forms of reduction."
    },
    {
        "anchor": "Scale setting the M\u00f6bius Domain Wall Fermion on gradient-flowed HISQ\n  action using the omega baryon mass and the gradient-flow scales $t_0$ and\n  $w_0$: We report on a sub-percent scale determination using the omega baryon mass\nand gradient-flow methods. The calculations are performed on 22 ensembles of\n$N_f=2+1+1$ highly improved, rooted staggered sea-quark configurations\ngenerated by the MILC and CalLat Collaborations. The valence quark action used\nis M\\\"obius Domain-Wall fermions solved on these configurations after a\ngradient-flow smearing is applied with a flowtime of $t_{\\rm gf}=1$ in lattice\nunits. The ensembles span four lattice spacings in the range $0.06 \\lesssim a\n\\lesssim 0.15$ fm, six pion masses in the range $130 \\lesssim m_\\pi \\lesssim\n400$ MeV and multiple lattice volumes. On each ensemble, the gradient-flow\nscales $t_0/a^2$ and $w_0/a$ and the omega baryon mass $a m_\\Omega$ are\ncomputed. The dimensionless product of these quantities is then extrapolated to\nthe continuum and infinite volume limits and interpolated to the physical\nlight, strange and charm quark mass point in the isospin limit, resulting in\nthe determination of $\\sqrt{t_0}=0.1422(14)$ fm and $w_0 = 0.1709(11)$ fm with\nall sources of statistical and systematic uncertainty accounted for. The\ndominant uncertainty in this result is the stochastic uncertainty, providing a\nclear path for a few-per-mille uncertainty, as recently obtained by the\nBudapest-Marseille-Wuppertal Collaboration.",
        "positive": "The Yang-Mills gradient flow in finite volume: The Yang-Mills gradient flow is considered on the four dimensional torus T^4\nfor SU(N) gauge theory coupled to N_f flavors of massless fermions in arbitrary\nrepresentations. The small volume dynamics is dominated by the constant gauge\nfields. The expectation value of the field strength tensor squared is\ncalculated for positive flow time t by treating the non-zero gauge modes\nperturbatively and the zero modes exactly. The finite volume correction to the\ninfinite volume result is found to contain both algebraic and exponential\nterms. The leading order result is then used to define a one parameter family\nof running coupling schemes in which the coupling runs with the linear size of\nthe box. The new scheme is tested numerically in SU(3) gauge theory coupled to\nN_f = 4 flavors of massless fundamental fermions. The calculations are\nperformed at several lattice spacings with a controlled continuum\nextrapolation. The continuum result agrees with the perturbative 2-loop\nprediction for small renormalized coupling as expected."
    },
    {
        "anchor": "Lattice QCD without tuning, mixing and current renormalization: The classically perfect action of QCD requires no tuning to get the pion\nmassless in the broken phase: the critical bare mass $m_q^c$ is zero. Neither\nthe vector nor the flavour non-singlet axial vector currents need\nrenormalization. Further, there is no mixing between four-fermion operators in\ndifferent chiral representations. The order parameter of chiral symmetry\nrequires, however, a subtraction which is given here explicitly. These results\nare based on the fact that the fixed point action satisfies the Ginsparg-Wilson\nremnant chiral symmetry condition. On chiral symmetry related questions any\nother local solution of this condition will produce similar results.",
        "positive": "Infrared behavior and Gribov ambiguity in SU(2) lattice gauge theory: For SU(2) lattice gauge theory we study numerically the infrared behavior of\nthe Landau gauge ghost and gluon propagators with the special accent on the\nGribov copy dependence. Applying a very efficient gauge fixing procedure and\ngenerating up to 80 gauge copies we find that the Gribov copy effect for both\npropagators is essential in the infrared. In particular, our best copy dressing\nfunction of the ghost propagator approaches a plateau in the infrared, while\nfor the random first copy it still grows. Our best copy zero-momentum gluon\npropagator shows a tendency to decrease with growing lattice size which\nexcludes singular solutions. Our results look compatible with the so-called\ndecoupling solution with a non-singular gluon propagator. However, we do not\nyet consider the Gribov copy problem to be finally resolved."
    },
    {
        "anchor": "Double-winding Wilson loops and monopole confinement mechanisms: We consider \"double-winding\" Wilson loops in SU(2) gauge theory. These are\ncontours which wind once around a loop $C_1$ and once around a loop $C_2$,\nwhere the two co-planar loops share one point in common, and where $C_1$ lies\nentirely in (or is displaced slightly from) the minimal area of $C_2$. We\ndiscuss the expectation value of such double-winding loops in abelian\nconfinement pictures, where the spatial distribution of confining abelian\nfields is controlled by either a monopole Coulomb gas, a caloron ensemble, or a\ndual abelian Higgs model, and argue that in such models an exponential falloff\nin the sum of areas $A_1+A_2$ is expected. In contrast, in a center vortex\nmodel of confinement, the behavior is an exponential falloff in the difference\nof areas $A_2-A_1$. We compute such double-winding loops by lattice Monte Carlo\nsimulation, and find that the area law falloff follows a difference-in-areas\nlaw. The conclusion is that even if confining gluonic field fluctuations are,\nin some gauge, mainly abelian in character, the spatial distribution of those\nabelian fields cannot be the distribution predicted by the simple monopole gas,\ncaloron ensemble, or dual abelian Higgs actions, which have been used in the\npast to explain the area law falloff of Wilson loops.",
        "positive": "Scale setting via the \u03a9 baryon mass: We present the first results of an ongoing effort to determine the lattice\nscale on the N_f=2 CLS lattice ensembles via the mass of the \\Omega\\ baryon.\nResults from different methods are compared, and various sources of systematic\nuncertainty are discussed."
    },
    {
        "anchor": "Primordial magnetic fields at preheating: Using lattice techniques we investigate the generation of long range\ncosmological magnetic fields during a cold electroweak transition. We will show\nhow magnetic fields arise, during bubble collisions, in the form of magnetic\nstrings. We conjecture that these magnetic strings originate from the alignment\nof magnetic dipoles associated with EW sphaleron-like configurations. We also\ndiscuss the early thermalisation of photons and the turbulent behaviour of the\nscalar fields after tachyonic preheating.",
        "positive": "APEnet+: a 3D toroidal network enabling Petaflops scale Lattice QCD\n  simulations on commodity clusters: Many scientific computations need multi-node parallelism for matching up both\nspace (memory) and time (speed) ever-increasing requirements. The use of GPUs\nas accelerators introduces yet another level of complexity for the programmer\nand may potentially result in large overheads due to the complex memory\nhierarchy. Additionally, top-notch problems may easily employ more than a\nPetaflops of sustained computing power, requiring thousands of GPUs\norchestrated with some parallel programming model. Here we describe APEnet+,\nthe new generation of our interconnect, which scales up to tens of thousands of\nnodes with linear cost, thus improving the price/performance ratio on large\nclusters. The project target is the development of the Apelink+ host adapter\nfeaturing a low latency, high bandwidth direct network, state-of-the-art wire\nspeeds on the links and a PCIe X8 gen2 host interface. It features hardware\nsupport for the RDMA programming model and experimental acceleration of GPU\nnetworking. A Linux kernel driver, a set of low-level RDMA APIs and an OpenMPI\nlibrary driver are available, allowing for painless porting of standard\napplications. Finally, we give an insight of future work and intended\ndevelopments."
    },
    {
        "anchor": "The radial wavefunctions of a heavy-light meson calculated on a lattice: A brief review is given of attempts to understand the energies of four-quark\nsystems calculated on a lattice in terms of nuclear-physics-inspired many-body\ntechniques involving interquark potentials. Results are given for the next\nstage of this study where the wavefunctions of heavy-light mesons are also\ncalculated on a lattice.",
        "positive": "Progress in Lattice Field Theory Algorithms: I present a summary of recent algorithmic developments for lattice field\ntheories. In particular I give a pedagogical introduction to the new\nMulticanonical algorithm, and discuss the relation between the Hybrid\nOverrelaxation and Hybrid Monte Carlo algorithms. I also attempt to clarify the\nrole of the dynamical critical exponent z and its connection with\n`computational cost.' [Includes four PostScript figures]"
    },
    {
        "anchor": "The meson spectrum in large-N QCD: We present lattice results on the meson spectrum and decay constants in\nlarge-N QCD. The results are obtained in the quenched approximation for N = 2,\n3, 4, 5, 6, 7 and 17 and extrapolated to infinite N.",
        "positive": "The kaon B-parameter from unquenched mixed action lattice QCD: We present a preliminary calculation of B_K using domain-wall valence quarks\nand 2+1 flavors of improved staggered sea quarks. Both the size of the residual\nquark mass, which measures the amount of chiral symmetry breaking, and of the\nmixed meson splitting Delta_mix, a measure of taste-symmetry breaking, show\nthat discretization effects are under control in our mixed action lattice\nsimulations. We show preliminary data for pseudoscalar meson masses, decay\nconstants and B_K. We discuss general issues associated with the chiral\nextrapolation of lattice data, and, as an example, present a preliminary chiral\nand continuum extrapolation of f_pi. The quality of our data shows that the\ngood chiral properties of domain-wall quarks, in combination with the light sea\nquark masses and multiple lattice spacings available with the MILC staggered\nconfigurations, will allow for a precise determination of B_K."
    },
    {
        "anchor": "Classical Simulation of Quantum Fields II: We consider the classical time evolution of a real scalar field in 2\ndimensional Minkowski space with a $\\lambda \\phi^4$ interaction. We compute the\nspatial and temporal two-point correlation functions and extract the\nrenormalized mass of the interacting theory. We find our results are consistent\nwith the one- and two-loop quantum computation. We also perform Monte Carlo\nsimulations of the quantum theory and conclude that the classical scheme is\nable to produce more accurate results with a fraction of the CPU time.",
        "positive": "Application of heavy-quark effective theory to lattice QCD: III.\n  Radiative corrections to heavy-heavy currents: We apply heavy-quark effective theory (HQET) to separate long- and\nshort-distance effects of heavy quarks in lattice gauge theory. In this paper\nwe focus on flavor-changing currents that mediate transitions from one heavy\nflavor to another. We stress differences in the formalism for heavy-light\ncurrents, which are discussed in a companion paper, showing how HQET provides a\nsystematic matching procedure. We obtain one-loop results for the matching\nfactors of lattice currents, needed for heavy-quark phenomenology, such as the\ncalculation of zero-recoil form factors for the semileptonic decays $B\\to\nD^{(*)}l\\nu$. Results for the Brodsky-Lepage-Mackenzie scale $q^*$ are also\ngiven."
    },
    {
        "anchor": "Euclidean Dynamical Triangulations Revisited: We conduct numerical simulations of a model of four dimensional quantum\ngravity in which the path integral over continuum Euclidean metrics is\napproximated by a sum over combinatorial triangulations. At fixed volume the\nmodel contains a discrete Einstein-Hilbert term with coupling $\\kappa$ and\nlocal measure term with coupling $\\beta$ that weights triangulations according\nto the number of simplices sharing each vertex. We map out the phase diagram in\nthis two dimensional parameter space and compute a variety of observables that\nyield information on the nature of any continuum limit. Our results are\nconsistent with a line of first order phase transitions with a latent heat that\ndecreases as $\\kappa\\to\\infty$. We find a Hausdorff dimension along the\ncritical line that approaches $D_H=4$ for large $\\kappa$ and a spectral\ndimension that is consistent with $D_s=\\frac{3}{2}$ at short distances. These\nresults are broadly in agreement with earlier works on Euclidean dynamical\ntriangulation models which utilize degenerate triangulations and/or different\nmeasure terms and indicate that such models exhibit a degree of universality.",
        "positive": "Generative Diffusion Models for Lattice Field Theory: This study delves into the connection between machine learning and lattice\nfield theory by linking generative diffusion models (DMs) with stochastic\nquantization, from a stochastic differential equation perspective. We show that\nDMs can be conceptualized by reversing a stochastic process driven by the\nLangevin equation, which then produces samples from an initial distribution to\napproximate the target distribution. In a toy model, we highlight the\ncapability of DMs to learn effective actions. Furthermore, we demonstrate its\nfeasibility to act as a global sampler for generating configurations in the\ntwo-dimensional $\\phi^4$ quantum lattice field theory."
    },
    {
        "anchor": "On $T$ dependence of the static potential $V(T;{\\vec R})$ in a finite\n  volume: We study the dependence on $T$ of the static potential $V(T;{\\vec R})$\ndefined from Wilson loops and from Polyakov loop correlators on a finite\nlattice. For this study we employ a simple model with confinement, and compare\nwith MC results.",
        "positive": "Towards a non-perturbative matching of HQET and QCD with dynamical light\n  quarks: We explain how the strategy of solving renormalization problems in HQET\nnon-perturbatively by a matching to QCD in finite volume can be implemented to\ninclude dynamical fermions. As a primary application, some elements of an HQET\ncomputation of the mass of the b-quark beyond the leading order with N_f=2 are\noutlined. In particular, the matching of HQET and QCD requires relativistic QCD\nsimulations in a volume with L ~ 0.5 fm, which will serve to quantitatively\ndetermine the heavy quark mass dependence of heavy-light meson observables in\nthe continuum limit of finite-volume two-flavour lattice QCD. As a preparation\nfor the latter, we report on our determination of the renormalization constants\nand improvement coefficients relating the renormalized current and subtracted\nbare quark mass in the relevant weak coupling region. The calculation of these\ncoefficients employs a constant physics condition in the Schroedinger\nfunctional scheme, where the box size L is fixed by working at a prescribed\nvalue of the renormalized coupling."
    },
    {
        "anchor": "Higher representations on the lattice: numerical simulations. SU(2) with\n  adjoint fermions: We discuss the lattice formulation of gauge theories with fermions in\narbitrary representations of the color group, and present in detail the\nimplementation of the HMC/RHMC algorithm for simulating dynamical fermions. We\ndiscuss the validation of the implementation through an extensive set of tests,\nand the stability of simulations by monitoring the distribution of the lowest\neigenvalue of the Wilson-Dirac operator. Working with two flavors of Wilson\nfermions in the adjoint representation, benchmark results for realistic lattice\nsimulations are presented. Runs are performed on different lattice sizes\nranging from 4^3x8 to 24^3x64 sites. For the two smallest lattices we also\nreport the measured values of benchmark mesonic observables. These results can\nbe used as a baseline for rapid cross-checks of simulations in higher\nrepresentations. The results presented here are the first steps towards more\nextensive investigations with controlled systematic errors, aiming at a\ndetailed understanding of the phase structure of these theories, and of their\nviability as candidates for strong dynamics beyond the Standard model.",
        "positive": "Analysis of short-distance current correlators using OPE: We investigate the correlators of flavor non-singlet bilinear operators\ncalculated on the lattice at short distances. In the continuum theory,\nnon-perturbative effects are encoded in the form of the operator product\nexpansion (OPE). We test the prediction of OPE by comparing lattice results\nwith those in the continuum theory. We also determine the renormalization\nfactors of quark currents."
    },
    {
        "anchor": "On the dynamics of color magnetic monopoles in full QCD: We present first results on the dynamics of monopoles in full QCD with N_f=2\nflavors of dynamical quarks. Among the quantities being studied are the\nmonopole density and the monopole screening length, the static potential as\nwell as the profile of the color electric flux tube. Furthermore, we derive the\nlow-energy effective monopole action.",
        "positive": "Evidence for shallow bound states and hints for broad resonances with\n  quark content $\\bar{b}\\bar{c}ud$ in $B$-$\\bar{D}$ and $B^*$-$\\bar{D}$\n  scattering from lattice QCD: We present the first determination of the energy dependence of the\n$B$-$\\bar{D}$ and $B^*$-$\\bar{D}$ isospin-0, $S$-wave scattering amplitudes\nboth below and above the thresholds using lattice QCD, which allows us to\ninvestigate rigorously whether mixed bottom-charm $\\bar{b}\\bar{c}ud$\ntetraquarks exist as bound states or resonances. The scattering phase shifts\nare obtained using L\\\"uscher's method from the energy spectra in two different\nvolumes. To ensure that no relevant energy level is missed, we use large,\nsymmetric $7 \\times 7$ and $8 \\times 8$ correlation matrices that include, at\nboth source and sink, $B^{(*)}$-$\\bar{D}$ scattering operators with the lowest\nthree or four possible back-to-back momenta in addition to local\n$\\bar{b}\\bar{c}ud$ operators. We fit the energy dependence of the extracted\nscattering phase shifts using effective-range expansions. We observe sharp\npeaks in the $B^{(*)}$-$\\bar{D}$ scattering rates close to the thresholds,\nwhich are associated with shallow bound states, either genuine or virtual, a\nfew MeV or less below the $B^{(*)}$-$\\bar{D}$ thresholds. In addition, we find\nhints for resonances with masses of order $100$ MeV above the thresholds and\ndecay widths of order $200$ MeV."
    },
    {
        "anchor": "Non-perturbative renormalization of lattice QCD at all scales: A general strategy to solve the non-perturbative renormalization problem in\nlattice QCD, using finite-size techniques and numerical simulations, is\ndescribed. As an illustration we discuss the computation of the axial current\nnormalization constant, the running coupling at zero quark masses and the scale\nevolution of the renormalized axial density. The non-perturbative calculation\nof O(a) correction terms (as they appear in Symanzik's improvement programme)\nis another important field of application.",
        "positive": "Interrelation of a Z(3) Gauge Theory on the Flat Lattices and a Spin-1\n  BEG Model: The Z(3) gauge model with double plaquette representation of the action on\nthe flat triangular and square lattices is constructed. It is reduced to the\nspin-1 Blume-Emery-Griffiths (BEG) model. An Ising-type critical line of a\nsecond-order phase transition is found."
    },
    {
        "anchor": "FLAG Review 2019: We review lattice results related to pion, kaon, $D$-meson, $B$-meson, and\nnucleon physics with the aim of making them easily accessible to the nuclear\nand particle physics communities. More specifically, we report on the\ndetermination of the light-quark masses, the form factor $f_+(0)$ arising in\nthe semileptonic $K \\to \\pi$ transition at zero momentum transfer, as well as\nthe decay constant ratio $f_K/f_\\pi$ and its consequences for the CKM matrix\nelements $V_{us}$ and $V_{ud}$. Furthermore, we describe the results obtained\non the lattice for some of the low-energy constants of $SU(2)_L\\times SU(2)_R$\nand $SU(3)_L\\times SU(3)_R$ Chiral Perturbation Theory. We review the\ndetermination of the $B_K$ parameter of neutral kaon mixing as well as the\nadditional four $B$ parameters that arise in theories of physics beyond the\nStandard Model. For the heavy-quark sector, we provide results for $m_c$ and\n$m_b$ as well as those for $D$- and $B$-meson decay constants, form factors,\nand mixing parameters. These are the heavy-quark quantities most relevant for\nthe determination of CKM matrix elements and the global CKM unitarity-triangle\nfit. We review the status of lattice determinations of the strong coupling\nconstant $\\alpha_s$. Finally, in this review we have added a new section\nreviewing results for nucleon matrix elements of the axial, scalar and tensor\nbilinears, both isovector and flavor diagonal.",
        "positive": "Energies and radial distributions of B_s mesons on the lattice: This is a follow-up to our earlier work for the energies and the charge\n(vector) and matter (scalar) distributions for S-wave states in a heavy-light\nmeson, where the heavy quark is static and the light quark has a mass about\nthat of the strange quark. We now study excited states of these mesons with\nhigher angular momentum and with radial nodes.\n  The calculation is carried out with dynamical fermions on a 16^3 times 32\nlattice with a lattice spacing approximately 0.10 fm. The lattice\nconfigurations were generated by the UKQCD Collaboration. Attempts are now\nbeing made to understand these results in terms of the Dirac equation. In\nnature the closest equivalent of this heavy-light system is the B_s meson,\nwhich allows us to compare our lattice calculations to experimental results\n(where available) or give a prediction where the P-wave states should lie. We\npay particular attention to the spin-orbit splitting, to see which one of the\nstates (for a given angular momentum L) has the lower energy."
    },
    {
        "anchor": "The rotator spectrum in the delta-regime of the O(n) effective field\n  theory in 3 and 4 dimensions: The low lying spectrum of the O(n) effective field theory is calculated in\nthe delta-regime in 3 and 4 space-time dimensions using lattice regularization\nto NNL order. It allows, in particular, to determine, using numerical\nsimulations in different spatial volumes, the pion decay constant F in QCD with\n2 flavours or the spin stiffness rho for an antiferromagnet in d=2+1\ndimensions.",
        "positive": "Phase Transitions in lattice QED: The main objective of the work presented here is to understand the appearance\nof phase transitions in pure gauge and scalar lattice QED. Main results are as\nfollows: Pure gauge compact QED with PBC shows a monopole percolation phenomena\ncoupled to the monopole condensation. Pure gauge compact QED with Fixed\nBoundary Conditions (spherical topology) shows a behaviour compatible with a\nsecond order phase transition The $\\gamma\\to\\infty$ limit of Non Compact Scalar\nQED with PBC is related to the Villain form of compact QED and also to the Loop\nModel for QED, showing a first order phase transition. Numerical a analysis of\na third rank abelian Z(2) theory shows an intriguing behaviour over the phase\ntransition that may be originated by point-like topological excitations."
    },
    {
        "anchor": "Effective Polyakov line actions, and their solutions at finite chemical\n  potential: I outline recent progress in the relative weights approach to deriving\neffective Polyakov line actions from an underlying lattice gauge theory, and\ncompare mean field and complex Langevin methods for solving such theories at\nfinite chemical potential.",
        "positive": "Model-independent parametrization of the hadronic vacuum polarization\n  and g-2 for the muon on the lattice: The leading hadronic contribution to the muon anomalous magnetic moment is\ngiven by a weighted integral over euclidean momentum of the hadronic vacuum\npolarization. This integral is dominated by momenta of order the muon mass.\nSince the finite volume in lattice QCD makes it difficult to compute the vacuum\npolarization at a large number of low momenta with high statistics (combined\nwith the fact that one cannot compute it at zero momentum), a parametrization\nof the vacuum polarization is required to extrapolate the data. A much used\nfunctional form is based on vector meson dominance, which introduces model\ndependence into the lattice computation of the magnetic moment. Here we\nintroduce a model-independent extrapolation method, and present a few first\ntests of this new method."
    },
    {
        "anchor": "An Algorithm for Gluinos on the Lattice: L\\\"uscher's local bosonic algorithm for Monte Carlo simulations of quantum\nfield theories with fermions is applied to the simulation of a possibly\nsupersymmetric Yang-Mills theory with a Majorana fermion in the adjoint\nrepresentation. Combined with a correction step in a two-step polynomial\napproximation scheme, the obtained algorithm seems to be promising and could be\ncompetitive with more conventional algorithms based on discretized classical\n(``molecular dynamics'') equations of motion. The application of the considered\npolynomial approximation scheme to optimized hopping parameter expansions is\nalso discussed.",
        "positive": "MCRG Flow for the nonlinear Sigma Model: A study of the renormalization group flow in the three-dimensional nonlinear\nO(N) sigma model using Monte Carlo Renormalization Group (MCRG) techniques is\npresented. To achieve this, we combine an improved blockspin transformation\nwith the canonical demon method to determine the flow diagram for a number of\ndifferent truncations. Systematic errors of the approach are highlighted.\nResults are discussed with hindsight on the fixed point structure of the model\nand the corresponding critical exponents. Special emphasis is drawn on the\nexistence of a nontrivial ultraviolet fixed point as required for theories\nmodeling the asymptotic safety scenario of quantum gravity."
    },
    {
        "anchor": "A Feynman-Hellmann approach to the spin structure of hadrons: We perform a Nf = 2 + 1 lattice QCD simulation to determine the quark spin\nfractions of hadrons using the Feynman-Hellmann theorem. By introducing an\nexternal spin operator to the fermion action, the matrix elements relevant for\nquark spin fractions are extracted from the linear response of the hadron\nenergies. Simulations indicate that the Feynman-Hellmann method offers\nstatistical precision that is comparable to the standard three-point function\napproach, with the added benefit that it is less susceptible to excited state\ncontamination. This suggests that the Feynman-Hellmann technique offers a\npromising alternative for calculations of quark line disconnected contributions\nto hadronic matrix elements. At the SU(3)-flavour symmetry point, we find that\nthe connected quark spin fractions are universally in the range 55-70% for\nvector mesons and octet and decuplet baryons. There is an indication that the\namount of spin suppression is quite sensitive to the strength of SU(3)\nbreaking.",
        "positive": "Finite temperature QCD phase transition with 3 flavors of M\u00f6bius\n  domain wall fermions: We investigate the finite temperature QCD phase transition with three\ndegenerate quark flavors using M\\\"{o}bius domain wall fermions. To explore the\norder of phase transition on the lower left corner of Columbia plot and if\npossible, to locate the critical endpoint we performed simulations at\ntemperatures around 181 and 121 MeV with lattice spacing $a=0.1361(20)$ fm\ncorresponding to temporal lattice extent $N_{\\tau}=8,12$ with varying quark\nmass for two different volumes with aspect ratios $N_{\\sigma}/N_{\\tau}$ ranging\nfrom 2 to 3. By analyzing the volume and mass dependence of the chiral\ncondensate, disconnected chiral susceptibility and Binder cumulant we find that\nthere is a crossover at $m_q^{\\mathrm{\\overline {MS}}}(2\\, \\mathrm{GeV}) \\sim\n44\\, \\mathrm{MeV}$ for $\\mathrm{T_{pc}}\\sim$ 181 MeV, At temperature 121 MeV,\nthe binder cumulant suggests a crossover at $m_q^{\\mathrm{\\overline {MS}}}(2\\,\n\\mathrm{GeV}) \\sim 3.7\\, \\mathrm{MeV}$, although a study of volume dependence\nwould be important to confirm this."
    },
    {
        "anchor": "Random manifolds and quantum gravity: The non-perturbative, lattice field theory approach towards the quantization\nof Euclidean gravity is reviewed. Included is a tentative summary of the most\nsignificant results and a presentation of the current state of art.",
        "positive": "Fixed boundary conditions and phase transitions in pure gauge compact\n  QED: We have simulated the pure gauge compact QED with fixed boundary conditions,\non lattices from $6^4$ to $16^4$. We argue that a lattice with this fixed\nboundary imposition corresponds actually to a lattice with spherical topology.\nWe have found the presence of a phase transition without any trace of\ndiscontinuity. Moreover, the specific heat and the Binder cumulant are\nqualitatively consistent with a second order phase transition. The implications\nof this observation on the nature of the compact lattice QED are discussed."
    },
    {
        "anchor": "Recent results in the center vortex model for the infrared sector of\n  Yang-Mills theory: A model for the infrared sector of SU(2) Yang-Mills theory, based on magnetic\nvortices represented by (closed) random surfaces, is presented. The model\nquantitatively describes both confinement and the topological aspects of\nYang-Mills theory. Details (including an adequate list of references) can be\nfound in hep-lat/9912003 and hep-lat/0004013, both to appear in Nucl. Phys. B.",
        "positive": "Gradient flow step-scaling function for SU(3) with $N_f=8$ fundamental\n  flavors: The step-scaling function, the lattice analog of the renormalization group\n$\\beta$ function, is presented for the SU(3) gauge system with eight flavors in\nthe fundamental representation. Our investigation is based on generating\ndynamical eight flavor gauge field configurations using stout-smeared M\\\"obius\ndomain wall fermions and Symanzik gauge action. On these gauge field\nconfigurations we perform gradient flow measurements using the Zeuthen, Wilson,\nor Symanzik kernel and consider the Symanzik, Wilson plaquette, or clover\noperators to determine step-scaling functions for a scale change $s=2$\nincluding large, up to $48^4$, volumes. Considering different flows and\noperators as well as the optional use of tree-level improvement allows us to\ncheck for possible systematic effects. Our result covers the range of\nrenormalized coupling up to $g_c^2 \\lesssim 10$. In the case of $N_f=8$ we\nobserve that the reach in $g_c^2$ is limited due to an unphysical first order\nbulk phase transition caused by large ultra-violet fluctuations.\n  We compare our findings to $N_f=4$, 6, 10 or 12 flavors results that are\nobtained using the same lattice action and analysis. In addition we investigate\nthe phase structure for simulations with different number of flavors using\nstout-smeared M\\\"obius domain wall fermions and Symanzik gauge actions to shed\nsome light on the limited reach in $g_c^2$."
    },
    {
        "anchor": "Lattice calculation of the $\u03c0^0$, $\u03b7$ and $\u03b7^{\\prime}$\n  transition form factors and the hadronic light-by-light contribution to the\n  muon $g-2$: In this paper we present a first ab-initio calculation of the $\\pi^0$, $\\eta$\nand $\\eta^{\\prime}$ transition form factors performed with physical light-quark\nmasses. We provide a complete parametrization of the form factors that includes\nboth single and double-virtual kinematics. Our results are compared with\nexperimental measurements of the form factors in the space-like region and with\nthe measured two-photon decay widths. In a second step, our parametrizations of\nthe transition form factors are used to compute the dominant pseudoscalar-pole\ncontributions to the hadronic light-by-light scattering in the muon $g-2$. Our\nfinal result reads $a_{\\mu}^{\\rm hlbl, ps-pole} = (85.1 \\pm 5.2) \\times\n10^{-11}$. Although the pion-pole is dominant, we confirm that, together, the\n$\\eta$ and $\\eta^{\\prime}$ provide roughly half of its contribution.",
        "positive": "The Yang-Mills gradient flow and lattice effective action: Recently, the Yang-Mills gradient flow is found to be a useful concept not\nonly in lattice simulations but also in continuous field theories. Since its\nsmearing property is similar to the Wilsoninan \"block spin transformation\",\nthere might be deeper connection between them. In this work, we define the\n\"effective action\" which generates configurations at a finite flow time and\nderive the exact differential equation to investigate the flow time dependence\nof the action. Then Yang-Mills gradient flow can be regarded as the flow of the\neffective action. We also propose the flow time dependent gradient, where the\ndifferential equation becomes similar to the renormalization group equation. We\ndiscuss a possibility to regard the time evolution of the effective action as\nthe Wilsonian renormalization group flow."
    },
    {
        "anchor": "Kaon semileptonic decay form factors in two-flavor QCD: We present a calculation of the kaon form factors in two-flavor QCD with the\nnon-perturbatively $O(a)$-improved Wilson quark action. In order to achieve a\nfew percent accuracy in the study of SU(3) breaking effects, we use a set of\ndouble ratios of the matrix elements, with which the bulk of the statistical\nfluctuation and the multiplicative renormalization factors cancel.",
        "positive": "A Study of the Static-Light $B_B$ Parameter: We calculate the $B_B$ parameter, relevant for $\\overline{B}^0$--$B^0$\nmixing, from a lattice gauge theory simulation using the static approximation\nfor the heavy quark and the Wilson action for the light quark and gauge fields.\nImproved sources, produced by an optimized variational technique, {\\sc most},\nreduce statistical errors and minimize excited-state contamination of the\nground-state signal. Renormalization of four-fermion operator coefficients,\nusing the Lepage-Mackenzie procedure for estimating typical momentum scales, is\nlinearized to reduce order $\\alpha_s^2$ uncertainties."
    },
    {
        "anchor": "Laplacian modes probing gauge fields: We show that low-lying eigenmodes of the Laplace operator are suitable to\nrepresent properties of the underlying SU(2) lattice configurations. We study\nthis for the case of finite temperature background fields, yet in the\nconfinement phase. For calorons as classical solutions put on the lattice, the\nlowest mode localizes one of the constituent monopoles by a maximum and the\nother one by a minimum, respectively. We introduce adjustable phase boundary\nconditions in the time direction, under which the role of the monopoles in the\nmode localization is interchanged. Similar hopping phenomena are observed for\nthermalized configurations. We also investigate periodic and antiperiodic modes\nof the adjoint Laplacian for comparison.\n  In the second part we introduce a new Fourier-like low-pass filter method. It\nprovides link variables by truncating a sum involving the Laplacian eigenmodes.\nThe filter not only reproduces classical structures, but also preserves the\nconfining potential for thermalized ensembles. We give a first characterization\nof the structures emerging from this procedure.",
        "positive": "The muon anomalous magnetic moment: is the lattice spacing small enough?: We present new results for the light-quark connected part of the leading\norder hadronic-vacuum-polarization (HVP) contribution to the muon anomalous\nmagnetic moment, using $2+1+1$ staggered fermions. We have collected more\nstatistics on previous ensembles, and we added two new ensembles. This allows\nus to reduce statistical errors on the HVP contribution and related window\nquantities significantly. We also calculated the current-current correlator to\nnext-to-next-to-leading order (NNLO) in staggered chiralperturbation theory, so\nthat we can correct to NNLO for finite-volume, pion-mass mistuning and\ntaste-breaking effects. We discuss the applicability of NNLO chiral\nperturbation theory, emphasizing that it provides a systematic EFT approach to\nthe HVP contribution, but not to short- or intermediate-distance window\nquantities. This makes it difficult to assess systematic errors on the standard\nintermediate-distance window quantity that is now widely considered in the\nliterature. In view of this, we investigate a longer-distance window, for which\nEFT methods should be more reliable. Our most important conclusion is that new\nhigh-statistics computations at lattice spacings significantly smaller than\n0.06 fm are indispensable. The ensembles we use have been generously provided\nby MILC and CalLat."
    },
    {
        "anchor": "Chiral symmetry breaking in fundamental and sextet fermion\n  representations of SU(3) color: We report new results for lattice gauge theories with twelve fermion flavors\nin the fundamental representation and two fermion flavors in the two-index\nsymmetric (sextet) representation of the SU(3) color gauge group. Both models\nare important in searching for a viable composite Higgs mechanism in the Beyond\nthe Standard Model (BSM) paradigm. We subject both models to opposite\nhypotheses inside and outside of the conformal window. In the first hypothesis\nwe test chiral symmetry breaking ($\\chi{\\rm SB}$) with its Goldstone spectrum,\n$F_\\pi$, the $\\chi{\\rm SB}$ condensate, and several composite hadron states as\nthe fermion mass is varied in a limited range with our best effort to control\nfinite volume effects. Supporting results for $\\chi{\\rm SB}$ from the running\ncoupling based on the force between static sources is also presented. In the\nsecond test for the alternate hypothesis we probe conformal behavior driven by\na single anomalous mass dimension under the assumption of unbroken chiral\nsymmetry. Our results show very low level of confidence in the conformal\nscenario.",
        "positive": "Scaling test for Wilson twisted mass QCD: We present a first scaling test of twisted mass QCD with pure Wilson quarks\nfor a twisting angle of pi/2. We have computed the vector meson mass and the\npseudoscalar decay constant for different values of beta at fixed value of r_0\nm_PS. The results obtained in the quenched approximation are compared with data\nfor pure Wilson and non-perturbatively O(a) improved Wilson computations. We\nshow that our results from Wilson twisted mass QCD show clearly reduced lattice\nspacing errors, consistent with O(a) improvement and without the need of any\nimprovement terms added. These results thus provide numerical evidence of the\nprediction in ref. [1]."
    },
    {
        "anchor": "Fermion production despite fermion number conservation: Lattice proposals for a nonperturbative formulation of the Standard Model\neasily lead to a global U(1) symmetry corresponding to exactly conserved\nfermion number. The absence of an anomaly in the fermion current would then\nappear to inhibit anomalous processes, such as electroweak baryogenesis in the\nearly universe. One way to circumvent this problem is to formulate the theory\nsuch that this U(1) symmetry is explicitly broken. However we argue that in the\nframework of spectral flow, fermion creation and annihilation still in fact\noccurs, despite the exact fermion number conservation. The crucial observation\nis that fermions are excitations relative to the vacuum, at the surface of the\nDirac sea. The exact global U(1) symmetry prohibits a state from changing its\nfermion number during time evolution, however nothing prevents the fermionic\nground state from doing so. We illustrate our reasoning with a model in two\ndimensions which has axial-vector couplings, first using a sharp momentum\ncutoff, then using the lattice regulator with staggered fermions. The\ndifference in fermion number between the time evolved state and the ground\nstate is indeed in agreement with the anomaly. A study of the vacuum energy\nshows that the perturbative counterterm needed for restoration of gauge\ninvariance is insufficient in a nonperturbative setting. For reference we also\nstudy a closely related model with vector couplings, the Schwinger model, and\nwe examine the emergence of the $\\theta$-vacuum structure of both theories.",
        "positive": "$O(a\u03b1_s)$ matching coefficients for the $\u0394B$=2 operators in\n  the lattice static theory: We present the perturbative matching coefficient to $O(a\\alpha_s)$ which\nrelates the $\\Delta B$=2 operator in the continuum to that of the lattice\nstatic theory, which is important in the accurate extraction of the continuum\nvalue of the $B_B$ from lattice simulations. The coefficients are obtained by\nthe one-loop calculations in both of the continuum and lattice theory. We find\nthat two new dimension seven operators appear at the $O(a\\alpha_s)$ with the\nO(1) coefficients. We also discuss the possible cancellation of $O(a\\alpha_s)$\ncorrection in the ratio $B_B=<\\bar{B}|\\Op_L|B>/ ((8/3)(f_{B}M_{B})^2)$\nqualitatively."
    },
    {
        "anchor": "Epsilon regime calculations with reweighted clover fermions: We perform fully dynamical simulations at small quark masses by reweighting\nin the quark mass, calculating the weight factors stochastically. This approach\navoids some of the technical difficulties associated with direct simulations.\nWe find that the weight factors fluctuate only moderately on nHYP smeared\ndynamical Wilson-clover ensembles, and demonstrate that the overlap between the\noriginal and reweighted configurations is large both for short and long\ndistance observables. We could successfully reweight 16^4, (1.85fm)^4 volume\nconfigurations from m_q 20 MeV to m_q~5 MeV, and 24^4, (2.77fm)^4\nconfigurations from m_q~8MeV to m_q~MeV quark masses, reaching the\nepsilon-regime. Using the pseudoscalar and axialvector correlators we predict\nthe low energy constants Sigma and F and study their volume and mass\ndependence.",
        "positive": "Curvature of the QCD critical line with 2+1 HISQ fermions: We present results on the curvature of the critical line of QCD with 2+1 HISQ\nfermions at nonzero temperature and quark density obtained by analytic\ncontinuation from imaginary chemical potentials. Monte Carlo simulations are\nperformed by means of the MILC code, suitably modified to include a nonzero\nimaginary baryon chemical potential. We set the chemical potential at the same\nvalue for the three quark species and work on the line of constant physics with\na light to strange mass ratio of 1/20 as determined in\nRef.~\\cite{Bazavov:2011nk}."
    },
    {
        "anchor": "Lattice Radial Quantization: 3D Ising: Lattice radial quantization is introduced as a nonperturbative method\nintended to numerically solve Euclidean conformal field theories that can be\nrealized as fixed points of known Lagrangians. As an example, we employ a\nlattice shaped as a cylinder with a 2D Icosahedral cross-section to discretize\ndilatations in the 3D Ising model. Using this method, we obtain the preliminary\nestimate eta=0.034(10).",
        "positive": "Computation of the string tension in four-dimensional Yang-Mills theory\n  using large N reduction: Continuum reduction and Monte Carlo simulation are used to calculate the\nheavy quark potential and the string tension in large N Yang-Mills theory in\nfour dimensions. The potential is calculated out to a separation of nine\nlattice units on a lattice with extent six in each direction."
    },
    {
        "anchor": "Study of topological quantities of lattice QCD by a modified Wasserstein\n  generative adversarial network: A modified Wasserstein generative adversarial network (M-WGAN) is proposed to\nstudy the distribution of the topological charge in lattice QCD based on the\nMonte Carlo (MC) simulations. We construct new generator and discriminator in\nM-WGAN to support the generation of high-quality distribution. Our results show\nthat the M-WGAN scheme of the Machine learning should be helpful for us to\ncalculate efficiently the 1D distribution of topological charge compared with\nthe results by the MC simulation alone.",
        "positive": "Logarithmic corrections to $\\mathbf{a^2}$ scaling in lattice QCD with\n  Wilson and Ginsparg-Wilson quarks: We analyse the leading logarithmic corrections to the $a^2$ scaling of\nlattice artefacts in QCD, following the seminal work of Balog, Niedermayer and\nWeisz in the O(n) non-linear sigma model. Limiting the discussion to\ncontributions from the action, the leading logarithmic corrections can be\ndetermined by the anomalous dimensions of mass-dimension 6 operators. These\noperators form a minimal on-shell basis of the Symanzik Effective Theory. We\npresent results for non-perturbatively O($a$) improved Wilson and\nGinsparg-Wilson quarks."
    },
    {
        "anchor": "SPHERICALLY SYMMETRIC RANDOM WALKS I. REPRESENTATION IN TERMS OF\n  ORTHOGONAL POLYNOMIALS: Spherically symmetric random walks in arbitrary dimension $D$ can be\ndescribed in terms of Gegenbauer (ultraspherical) polynomials. For example,\nLegendre polynomials can be used to represent the special case of\ntwo-dimensional spherically symmetric random walks. In general, there is a\nconnection between orthogonal polynomials and semibounded one-dimensional\nrandom walks; such a random walk can be viewed as taking place on the set of\nintegers $n$, $n=0,~1,~2,~\\ldots$, that index the polynomials. This connection\nallows one to express random-walk probabilities as weighted inner products of\nthe polynomials. The correspondence between polynomials and random walks is\nexploited here to construct and analyze spherically symmetric random walks in\n$D$-dimensional space, where $D$ is {\\sl not} restricted to be an integer. The\nweighted inner-product representation is used to calculate exact closed-form\nspatial and temporal moments of the probability distribution associated with\nthe random walk. The polynomial representation of spherically symmetric random\nwalks is also used to calculate the two-point Green's function for a\nrotationally symmetric free scalar quantum field theory.",
        "positive": "Low-Lying Fermion Modes: Dynamical versus Quenched: We compare the low-lying eigenmodes of the O(a) improved Wilson-Dirac\noperator on quenched and dynamical configurations and investigate methods of\nprobing the topological properties of gauge configurations"
    },
    {
        "anchor": "Lattice QCD with mixed actions: We discuss some of the implications of simulating QCD when the action used\nfor the sea quarks is different from that used for the valence quarks. We\npresent exploratory results for the hadron mass spectrum and pseudoscalar meson\ndecay constants using improved staggered sea quarks and HYP-smeared overlap\nvalence quarks. We propose a method for matching the valence quark mass to the\nsea quark mass and demonstrate it on UKQCD clover data in the simpler case\nwhere the sea and valence actions are the same.",
        "positive": "Gauge invariance of the dual Meissner effect in QCD: The dual Meissner effect is described and numerically observed in a\ngauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD.\n  A gauge-invariant Abelian-like field strength is defined in terms of a\nunit-vector in color space which is constructed by a non-Abelian field strength\nitself. A gauge-invariant monopole-like quantity is defined by a violation of\nthe Bianchi identity with respect to the Abelian-like field strength. The\nsqueezing of the non-Abelian electric field $\\sqrt{\\sum_a(E^a_i)^2}$ between a\npair of static quark and anti-quark occurs due to the solenoidal current coming\nfrom the gauge-invariant monopole-like quantity. An equation similar to the\ndual London equation is confirmed approximately in the long-range region."
    },
    {
        "anchor": "A specific lattice artefact in non-perturbative renormalization of\n  operators: We discuss a specific cut-off effect which appears in applying the\nnon-perturbative RI/MOM scheme to compute the renormalization constants. To\nillustrate the problem a Dirac operator satisfying the Ginsparg-Wilson relation\nis used, but the arguments are more general. We propose a simple modification\nof the method which gets rid of the corresponding discretization error.\nApplying this to full-QCD simulations done at a=0.13 fm with the Fixed Point\naction we find that the renormalization constants are strongly distorted by the\nartefacts discussed. We consider also the role of global gauge transformations,\na freedom which still remains after the conventional gauge fixing procedure is\napplied.",
        "positive": "Hybrid Monte Carlo Without Pseudofermions: We introduce a dynamical fermion algorithm which is based on the hybrid Monte\nCarlo (HMC) algorithm, but without pseudofermions. The molecular dynamics steps\nin HMC are retained except the derivatives with respect to the gauge fields are\ncalculated with the $Z_2$ noise. The determinant ratios are estimated with the\nPa\\`{d}e - $Z_2$ method. Finally, we use the Kennedy-Kuti linear accept/reject\nmethod for the Monte Carlo step which is shown to respect detailed balance. We\ncomment on the comparison of this algorithm with the pseudofermion algorithm."
    },
    {
        "anchor": "Complex Langevin for Lattice QCD: We simulate lattice QCD at finite quark-number chemical potential, $\\mu$,\nusing the complex-Langevin equation (CLE) with gauge-cooling and adaptive\nupdating to prevent instabilities. The CLE is used because QCD at finite $\\mu$\nhas a complex fermion determinant which precludes the use of standard\nsimulation methods based on importance sampling. Since, even when CLE\nsimulations converge, they are not guaranteed to produce correct results except\nunder very stringent conditions, which lattice QCD at finite $\\mu$ does not\nobey, we need extensive testing to determine under what conditions it produces\nreliable results. We performed simulations at $\\beta=6/g^2=5.6$ and\n$\\beta=5.7$, both at $m=0.025$. For small $\\mu$ and $\\mu$ large enough to\nproduce saturation, measured observables appear to be approaching their correct\nvalues as the coupling is decreased. However, for intermediate $\\mu$ values,\nthese simulations predict a transition from hadronic to nuclear matter at a\n$\\mu$ which is far too small. Since there is evidence that for CLE simulations\nto produce correct results the trajectories should remain close to the $SU(3)$\nmanifold (at least for small $\\mu$), we explore the parameter space to see\nwhere this is true. We find that the distance from this manifold decreases as\nthe coupling decreases and as the quark mass (in lattice units) decreases, i.e.\nas we approach the continuum limit. This indicates that we need to simulate at\nsmaller couplings and quark masses (requiring larger lattices) to see if these\ncan produce the correct physics.",
        "positive": "Phase diagram of the 2+1-dimensional Gross-Neveu model with chiral\n  imbalance: In this work, the phase diagram of the $2+1$-dimensional Gross-Neveu model is\ninvestigated with baryon chemical potential as well as chiral chemical\npotential in the mean-field approximation. We study the theory using two\nlattice discretizations, which are both based on naive fermions. An\ninhomogeneous chiral phase is observed only for one of the two discretizations.\nOur results suggest that this phase disappears in the continuum limit."
    },
    {
        "anchor": "Rigorous control of the non-perturbative corrections to the double\n  expansion in $g$ and $g^2\\ln(g)$ for the $\u03c6^4_3$-trajectory in the\n  hierarchical approximation: We study the renormalization invariant trajectory of the\n$\\phi^4$-perturbation of the free field fixed point in the hierarchical\napproximation. We parametrize it by a running $\\phi^4$-coupling $g$ with linear\nstep $\\beta$-function. We rigorously control the non-perturbative corrections\nto finite order approximants from double perturbation theory in $g$ and\n$g^2\\ln(g)$. The construction uses a contraction mapping for the extended\nrenormalization group composed of a hierarchical block spin transformation with\na flow of $g$.",
        "positive": "The decay of unstable strings in SU(2) Yang-Mills theory: We investigate the stability of strings connecting charges Q in the\nrepresentation {2Q+1} of SU(2) Yang-Mills theory in (2+1) dimensions. While the\nfundamental {2}-string between two charges Q=1/2 is unbreakable and stable, the\nstring connecting static charges transforming under any other representation\nQ>1/2 is unstable and decays. A charge Q=1 can be completely screened by gluons\nand so the adjoint {3}-string ultimately breaks. A charge Q=3/2 can be only\npartially screened to a fundamental charge Q=1/2. Thus, stretching a {4}-string\nbeyond a critical length, it decays into the stable {2}-string by gluon pair\ncreation. The complete breaking of a {5}-string happens in two steps, it first\ndecays into a {3}-string and then breaks completely. A phenomenological\nconstituent gluon model provides a good quantitative description of the energy\nof the screened charges at the ends of an unstable string."
    },
    {
        "anchor": "Simulating an arbitrary number of flavors of dynamical overlap fermions: We present a set of related Hybrid Monte Carlo methods to simulate an\narbitrary number of dynamical overlap fermions. Each fermion is represented by\na chiral pseudo-fermion field. The new algorithm reduces critical slowing down\nin the chiral limit and for sectors of nontrivial topology.",
        "positive": "Sigma models on quantum computers: We formulate a discretization of sigma models suitable for simulation by\nquantum computers. Space is substituted by a lattice, as usually done in\nlattice field theory, while the target space (a sphere) is replaced by the\n\"fuzzy sphere\", a construction well known from non-commutative geometry.\nContrary to more naive discretizations of the sphere, in this construction the\nexact $O(3)$ symmetry is maintained, which suggests that the discretized model\nis in the same universality class as the continuum model. That would allow for\ncontinuum results to be obtained for very rough discretizations of the target\nspace as long as the space discretization is made fine enough. The cost of\nperforming time-evolution, measured as the number of CNOT operations necessary,\nis $12 L T/\\Delta t $, where $L$ is the number of spatial sites, $T$ the\nmaximum time extent and $\\Delta t$ the time spacing."
    },
    {
        "anchor": "Explicit positive representation for weights on $R^d$: It is an old idea to replace averages of observables with respect to a\ncomplex weight by expectation values with respect to a genuine probability\nmeasure on complexified space. This is precisely what one would like to get\nfrom complex Langevin simulations. Unfortunately, these fail in many cases of\nphysical interest. We will describe method of deriving positive representations\nby matching of moments and show simple examples of successful constructions. It\nwill be seen that the problem is greatly underdetermined.",
        "positive": "Perturbative analysis of the Neuberger-Dirac operator in the\n  Schr\u00f6dinger functional: We investigate the spectrum of the free Neuberger-Dirac operator $\\Dov$ on\nthe Schr\\\"odinger functional (SF). We check that the lowest few eigen-values of\nthe Hermitian operator $\\Dov^{\\dag}\\Dov$ in unit of $L^{-2}$ converge to the\ncontinuum limit properly. We also perform a one-loop calculation of the SF\ncoupling, and then check the universality and investigate lattice artifacts of\nthe step scaling function. It turns out that the lattice artifacts for the\nNeuberger-Dirac operator are comparable in those of the clover action."
    },
    {
        "anchor": "I=2 Two-Pion Wave Function and Scattering Phase Shift: We calculate a two-pion wave function for the I=2 $S$-wave two-pion system\nwith a finite scattering momentum and estimate the interaction range between\ntwo pions, which allows us to examine the validity of a necessary condition for\nthe finite size formula presented by Rummukainen and Gottlieb. We work in the\nquenched approximation employing the plaquette gauge action for gluons and the\nimproved Wilson action for quarks at $1/a=1.63 {\\rm GeV}$ on $32^3\\times 120$\nlattice. The quark masses are chosen to give $m_\\pi = 0.420$, 0.488 and $0.587\n{\\rm GeV}$. We find that the energy dependence of the interaction range is\nsmall and the necessary condition is satisfied for our range of the quark mass\nand the scattering momentum, $k \\le 0.16 {\\rm GeV}$. We also find that the\nscattering phase shift can be obtained with a smaller statistical error from\nthe two-pion wave function than from the two-pion time correlator.",
        "positive": "Super Yang-Mills on the lattice with domain wall fermions: The dynamical N=1, SU(2) Super Yang-Mills theory is studied on the lattice\nusing a new lattice fermion regulator, domain wall fermions. This formulation\neven at non-zero lattice spacing does not require fine-tuning, has improved\nchiral properties and can produce topological zero-mode phenomena. Numerical\nsimulations of the full theory on lattices with the topology of a torus\nindicate the formation of a gluino condensate which is sustained at the chiral\nlimit. The condensate is non-zero even for small volume and small supersymmetry\nbreaking mass where zero mode effects due to gauge fields with fractional\ntopological charge appear to play a role."
    },
    {
        "anchor": "Spatial volume dependence for 2+1 dimensional SU(N) Yang-Mills theory: We study the 2+1 dimensional SU(N) Yang-Mills theory on a finite two-torus\nwith twisted boundary conditions. Our goal is to study the interplay between\nthe rank of the group N, the length of the torus L and the Z_N magnetic flux.\nAfter presenting the classical and quantum formalism, we analyze the spectrum\nof the theory using perturbation theory to one-loop and using Monte Carlo\ntechniques on the lattice. In perturbation theory, results to all orders depend\non the combination x=\\lambda NL and an angle defined in terms of the magnetic\nflux (\\lambda\\ is 't Hooft coupling). Thus, fixing the angle, the system\nexhibits a form of volume independence (NL dependence). The numerical results\ninterpolate between our perturbative calculations and the confinement regime.\nThey are consistent with x-scaling and provide interesting information about\nthe k-string spectrum and effective string theories. The occurrence of\ntachyonic instabilities is also analysed. They seem to be avoidable in the\nlarge N limit with a suitable scaling of the magnetic flux.",
        "positive": "Localization and lattice fermions: I review how the phenomenology of localization applies to fermions in lattice\ngauge theory, present measurements of the localization length and other\nquantities, and discuss the consequences for things like the overlap kernel."
    },
    {
        "anchor": "The International Lattice Data Grid -- towards FAIR Data: The International Lattice Data Grid (ILDG) is a community-wide initiative to\nrealize the sharing of primary data from lattice QCD simulations according to\nthe principles of FAIR data. We recall the basic concepts of ILDG as a\nfederation of autonomous regional grids with common standards for (meta-)data\nand services, and report on current activities, progress, and plans to restore\nand extend the usability of ILDG.",
        "positive": "Determination of the $A_2$ amplitude of $K \\rightarrow \u03c0\u03c0$ decays: We review the status of recent calculations by the RBC-UKQCD collaboration of\nthe complex amplitude $A_2$, corresponding to the decay of a kaon to a two pion\nstate with total isospin 2. In particular, we present preliminary results from\ntwo new ensembles: $48^3 \\times 96$ with $a^{-1}=1.73$ GeV and $64^3 \\times\n128$ with $a^{-1}=2.3$ GeV, both at physical kinematics. Both ensembles were\ngenerated Iwasaki gauge action and domain wall fermion action with 2+1\nflavours. These results, in comparison to our earlier ones on a $32^3$ DSDR\nlattice with $a^{-1}=1.36$ GeV, enable us to significantly reduce the\ndiscretization errors. The partial cancellation between the two dominant\ncontractions contributing to Re($A_2$) has been confirmed and we believe that\nthis cancellation is a major contribution to the $\\Delta I=1/2$ rule."
    },
    {
        "anchor": "Meron-Cluster Simulation of a Chiral Phase Transition with Staggered\n  Fermions: We examine a (3+1)-dimensional model of staggered lattice fermions with a\nfour-fermion interaction and Z(2) chiral symmetry using the Hamiltonian\nformulation. This model cannot be simulated with standard fermion algorithms\nbecause those suffer from a very severe sign problem. We use a new fermion\nsimulation technique - the meron-cluster algorithm - which solves the sign\nproblem and leads to high-precision numerical data. We investigate the finite\ntemperature chiral phase transition and verify that it is in the universality\nclass of the 3-d Ising model using finite-size scaling.",
        "positive": "Some hadronic parameters of charmonia in $\\boldsymbol{N_{\\text{f}}=2}$\n  lattice QCD: The phenomenology of leptonic decays of quarkonia holds many interesting\nfeatures: for instance, it can establish constraints on scenarios beyond the\nStandard Model with the Higgs sector enriched by a light CP-odd state. In the\nfollowing paper, we report on a two-flavor lattice QCD study of the $\\eta_c$\nand $J/\\psi$ decay constants, $f_{\\eta_c}$ and $f_{J\\psi}$. We also examine\nsome properties of the first radial excitation $\\eta_c(2S)$ and $\\psi(2S)$."
    },
    {
        "anchor": "$\u03c1$ Meson Decay in 2+1 Flavor Lattice QCD: We perform a lattice QCD study of the $\\rho$ meson decay from the $N_f=2+1$\nfull QCD configurations generated with a renormalization group improved gauge\naction and a non-perturbatively $O(a)$-improved Wilson fermion action. The\nresonance parameters, the effective $\\rho\\to\\pi\\pi$ coupling constant and the\nresonance mass, are estimated from the $P$-wave scattering phase shift for the\nisospin I=1 two-pion system. The finite size formulas are employed to calculate\nthe phase shift from the energy on the lattice. Our calculations are carried\nout at two quark masses, $m_\\pi=410\\,{\\rm MeV}$ ($m_\\pi/m_\\rho=0.46$) and\n$m_\\pi=300\\,{\\rm MeV}$ ($m_\\pi/m_\\rho=0.35$), on a $32^3\\times 64$\n($La=2.9\\,{\\rm fm}$) lattice at the lattice spacing $a=0.091\\,{\\rm fm}$. We\ncompare our results at these two quark masses with those given in the previous\nworks using $N_f=2$ full QCD configurations and the experiment.",
        "positive": "A novel method for the physical scale setting on the lattice and its\n  application to $N_f$=4 simulations: This letter reports on a new procedure for the lattice spacing setting that\ntakes advantage of the very precise determination of the strong coupling in\nTaylor scheme. Although it can be applied for the physical scale setting with\nthe experimental value of $\\Lambda_{\\overline{\\rm MS}}$ as an input, the\nprocedure is particularly appropriate for relative \"calibrations\". The method\nis here applied for simulations with four degenerate light quarks in the sea\nand leads to prove that their physical scale is compatible with the same one\nfor simulations with two light and two heavy flavours."
    },
    {
        "anchor": "SU(2) Lattice Gauge Theory with Logarithmic Action: Scaling and\n  Universality: We investigate a version of SU(2) lattice gauge theory with a logarithmic\naction. The model is found to exhibit confinement, contrary to previous claims\nin the literature. Comparing ratios of physical quantities, like\n$\\sqrt{\\sigma}/T_c$, we find that the model belongs to the same universality\nclass as the standard SU(2) lattice gauge theory with Wilson action. Like the\npositive plaquette model, the model with logarithmic action has a monotonic\n$\\beta$-function, without the famous dip exhibited by the Wilson action. Short\ndistance dislocations affecting the definition of topology are slightly more\nsuppressed than for the positive plaquette model.",
        "positive": "Variance reduction via deflation with local coherence: In large enough volumes, translation-averaging for quark-line connected\ndiagrams reduces the variance inversely proportional to the volume. Stochastic\nestimators which implement translation averaging however introduce new sources\nof fluctuations, which in some cases can be relatively large. In this work, we\nexplore whether inexact deflation subspaces can be used to improve the\nprecision of the isovector vector correlators. We perform numerical experiments\nwith $N_\\mathrm{f}=2$ non-perturbatively $\\mathrm O(a)$-improved Wilson\nfermions and measure the relative contribution from the deflation subspace to\nthe central value and the corresponding variance."
    },
    {
        "anchor": "$I=1/2$ $S$-wave and $P$-wave $K\u03c0$ scattering and the $\u03ba$ and\n  $K^*$ resonances from lattice QCD: We present a lattice-QCD determination of the elastic isospin-$1/2$ $S$-wave\nand $P$-wave $K\\pi$ scattering amplitudes as a function of the center-of-mass\nenergy using L\\\"uscher's method. We perform global fits of $K$-matrix\nparametrizations to the finite-volume energy spectra for all irreducible\nrepresentations with total momenta up to $\\sqrt{3}\\frac{2\\pi}{L}$; this\nincludes irreps that mix the $S$- and $P$-waves. Several different\nparametrizations for the energy dependence of the $K$-matrix are considered. We\nalso determine the positions of the nearest poles in the scattering amplitudes,\nwhich correspond to the broad $\\kappa$ resonance in the $S$-wave and the narrow\n$K^*(892)$ resonance in the $P$-wave. Our calculations are performed with $2+1$\ndynamical clover fermions for two different pion masses of $317.2(2.2)$ and\n$175.9(1.8)$ MeV. Our preferred $S$-wave parametrization is based on a\nconformal map and includes an Adler zero; for the $P$-wave we use a standard\npole parametrization including Blatt-Weisskopf barrier factors. The $S$-wave\n$\\kappa$-resonance pole positions are found to be $\\left[0.86(12) -\n0.309(50)\\,i\\right]\\:{\\rm GeV}$ at the heavier pion mass and $\\left[0.499(55)-\n0.379(66)\\,i\\right]\\:{\\rm GeV}$ at the lighter pion mass. The $P$-wave\n$K^*$-resonance pole positions are found to be $\\left[ 0.8951(64) -\n0.00250(21)\\,i \\right]\\:{\\rm GeV}$ at the heavier pion mass and\n$\\left[0.8718(82) - 0.0130(11)\\,i\\right]\\:{\\rm GeV}$ at the lighter pion mass,\nwhich corresponds to couplings of $g_{K^* K\\pi}=5.02(26)$ and $g_{K^*\nK\\pi}=4.99(22)$, respectively.",
        "positive": "Effective chiral restoration in the rho'-meson in lattice QCD: In simulations with dynamical quarks it has been established that the ground\nstate rho in the infrared is a strong mixture of the two chiral representations\n(0,1)+(1,0) and (1/2,1/2)_b. Its angular momentum content is approximately the\n3S1 partial wave which is consistent with the quark model. Effective chiral\nrestoration in an excited rho-meson would require that in the infrared this\nmeson couples predominantly to one of the two representations. The variational\nmethod allows one to study the mixing of interpolators with different chiral\ntransformation properties in the non-perturbatively determined excited state at\ndifferent resolution scales. We present results for the first excited state of\nthe rho-meson using simulations with n_f=2 dynamical quarks. We point out, that\nin the infrared a leading contribution to rho'= rho(1450) comes from\n(1/2,1/2)_b, in contrast to the rho. Its approximate chiral partner would be a\nh_1(1380) state. The rho' wave function contains a significant contribution of\nthe 3D1 wave which is not consistent with the quark model prediction."
    },
    {
        "anchor": "The chiral condensate from the Dirac spectrum in BSM gauge theories: The eigenvalues of the Dirac operator at finite volume encode whether or not\nchiral symmetry is spontaneously broken in a massless theory. We apply this\nframework in a particular BSM context, namely SU(3) gauge theory with N_f=2\nmassless flavors in the 2-index symmetric (sextet) representation. Our first\nresults are at a single lattice spacing. We find that both the density of\nnear-zero eigenvalues and the renormalization group invariant mode number\nindicate spontaneous symmetry breaking. Quantitatively, there is a discrepancy\nbetween the determination of the fermion condensate in the chiral limit via the\neigenvalue spectrum and the determinations from direct measurements of the\nchiral condensate and the GMOR relation. We comment on possible explanations of\nthis discrepancy and further refinements of this study.",
        "positive": "Spectrum of the open QCD flux tube in d=2+1 and its effective string\n  description: Simulations in lattice gauge theory suggest that the formation of a flux tube\nbetween quark and antiquark leads to quark confinement. It is conjectured that\nthe infrared behaviour of the flux tube is governed by an effective string\ntheory and simulations show good agreement between lattice data and its\npredictions. To next-to leading order ($R^{-3}$) in the inverse $q\\bar{q}$\nseparation $R$ the effective string theory is equivalent to Nambu-Goto string\ntheory. For the open flux tube in three dimensions corrections appear at order\n$R^{-4}$. We compare these predictions to high-accuracy measurements of the\ngroundstate energy of the flux tube in 3d SU(2) and SU(3) gauge theory and\nextract the coefficient of the leading order boundary term in the effective\naction."
    },
    {
        "anchor": "Numerical study of lattice index theorem usingimproved cooling and\n  overlap fermions: We investigate topological charge and the index theorem on finite lattices\nnumerically. Using mean field improved gauge field configurations we calculate\nthe topological charge Q using the gluon field definition with ${\\cal\nO}(a^4)$-improved cooling and an ${\\cal O}(a^4)$-improved field strength tensor\n$F_{\\mu\\nu}$. We also calculate the index of the massless overlap fermion\noperator by directly measuring the differences of the numbers of zero modes\nwith left- and right--handed chiralities. For sufficiently smooth field\nconfigurations we find that the gluon field definition of the topological\ncharge is integer to better than 1% and furthermore that this agrees with the\nindex of the overlap Dirac operator, i.e., the Atiyah-Singer index theorem is\nsatisfied. This establishes a benchmark for reliability when calculating\nlattice quantities which are very sensitive to topology.",
        "positive": "Tensor renormalization group study of 3D principal chiral model: We study the three-dimensional $SU(2)$ principal chiral model (PCM) using\ndifferent tensor renormalization group methods based on the triad and\nanisotropic decomposition of the tensor. The tensor network representation is\nformulated based on the character expansion of the Boltzmann weight. We compare\nthe average action obtained using these two tensor network algorithms and\nconfirm that the resulting critical coupling and exponent are comparable with\nthe recent estimations from the Monte Carlo methods."
    },
    {
        "anchor": "Center Vortices, Area Law and the Catenary Solution: We present meson-meson (Wilson loop) correlators in Z(2) center vortex models\nfor the infrared sector of Yang-Mills theory, i.e., a hypercubic lattice model\nof random vortex surfaces and a continuous 2+1 dimensional model of random\nvortex lines. In particular we calculate quadratic and circular Wilson loop\ncorrelators in the two models respectively and observe that their expectation\nvalues follow the area law and show string breaking behavior. Further we\ncalculate the catenary solution for the two cases and try to find indications\nfor minimal surface behavior or string surface tension leading to string\nconstriction.",
        "positive": "Efficient Simulation of Heavy Quark Vacuum Polarization: We outline a simple way to include heavy quark vacuum polarization in lattice\nQCD simulations. The method, based on effective field theory, requires only a\ntrivial modification of the gluon action and has no impact on simulation times.\nWe assess the range of validity for this procedure, and the impact that it may\nhave."
    },
    {
        "anchor": "$\u039e_c-\u039e_c^{\\prime}$ mixing From Lattice QCD: In heavy quark limit, the lowest-lying charmed baryons with two light quarks\ncan form an SU(3) triplet and sextet. The $\\Xi_c$ in the SU(3) triplet and\n$\\Xi_c'$ in the sextet have the same $J^{PC}$ quantum number and can mix due to\nthe finite charm quark mass and the fact the strange quark is heavier than the\nup/down quark. We explore the $\\Xi_c$-$\\Xi_c'$ mixing by calculating the\ntwo-point correlation functions of the $\\Xi_c$ and $\\Xi_c'$ baryons from\nlattice QCD. Based on the lattice data, we adopt two independent methods to\ndetermine the mixing angle between $\\Xi_c$ and $\\Xi_c'$. After making the\nchiral and continuum extrapolation, it is found that the mixing angle $\\theta$\nis $1.2^{\\circ}\\pm0.1^{\\circ}$, which seems insufficient to account for the\nlarge SU(3) symmetry breaking effects found in weak decays of charmed baryons.",
        "positive": "The elastic $I=3/2$ $p$-wave nucleon-pion scattering amplitude and the\n  $\u0394(1232)$ resonance from $N_{\\mathrm{f}}=2+1$ lattice QCD: We present the first direct determination of meson-baryon resonance\nparameters from a scattering amplitude calculated using lattice QCD. In\nparticular, we calculate the elastic $I=3/2$, $p$-wave nucleon-pion amplitude\non a single ensemble of $N_{\\mathrm{f}}=2+1$ Wilson-clover fermions with\n$m_{\\pi}=280\\mathrm{MeV}$ and $m_{K}=460\\mathrm{MeV}$. At these quark masses,\nthe $\\Delta(1232)$ resonance pole is found close to the $N-\\pi$ threshold and a\nBreit-Wigner fit to the amplitude gives $g^{\\mathrm{BW}}_{\\Delta\nN\\pi}=19.0(4.7)$ in agreement with phenomenological determinations."
    },
    {
        "anchor": "Non-perturbative renormalization of meson decay constants in quenched\n  QCD for a renormalization group improved gauge action: Renormalization constants ($Z$-factors) of vector and axial-vector currents\nare determined non-perturbatively in quenched QCD for a renormalization group\nimproved gauge action and a tadpole improved clover quark action using the\nSchr\\\"odinger functional method. Non-perturbative values of $Z$-factors turn\nout to be smaller than one-loop perturbative values by $O(15%)$ at lattice\nspacing of $a^{-1}\\approx$ 1 GeV. The pseudoscalar and vector meson decay\nconstants calculated with the non-perturbative $Z$-factors show a much better\nscaling behavior compared to previous results obtained with tadpole improved\none-loop $Z$-factors. In particular, the non-perturbative $Z$-factors\nnormalized at infinite physical volume show that scaling violation of the decay\nconstants are within about 10% up to the lattice spacing $a^{-1}\\sim 1$ GeV.\nThe continuum estimates obtained from data in the range $a^{-1}=$ 1 -- 2 GeV\nagree with those determined from finer lattices ($a^{-1}\\sim 2-4$ GeV) with the\nstandard action.",
        "positive": "Testing UV-filtered (\"fat-link\") clover fermions: We investigate filtered clover fermions, built from fat gauge links, both in\none-loop perturbation theory and in numerical simulations. We use a variety of\nfiltering recipes (APE, HYP, EXP, HEX), some of which are suitable for a HMC\nwith dynamical fermions. A generic filtering together with a (fat-link) clover\nterm yields fermions with much reduced chiral symmetry breaking."
    },
    {
        "anchor": "A Monte Carlo algorithm for simulating fermions on Lefschetz thimbles: A possible solution of the notorious sign problem preventing direct Monte\nCarlo calculations for systems with non-zero chemical potential is to deform\nthe integration region in the complex plane to a Lefschetz thimble. We\ninvestigate this approach for a simple fermionic model. We introduce an easy to\nimplement Monte Carlo algorithm to sample the dominant thimble. Our algorithm\nrelies only on the integration of the gradient flow in the numerically stable\ndirection, which gives it a distinct advantage over the other proposed\nalgorithms. We demonstrate the stability and efficiency of the algorithm by\napplying it to an exactly solvable fermionic model and compare our results with\nthe analytical ones. We report a very good agreement for a certain region in\nthe parameter space where the dominant contribution comes from a single\nthimble, including a region where standard methods suffer from a severe sign\nproblem. However, we find that there are also regions in the parameter space\nwhere the contribution from multiple thimbles is important, even in the\ncontinuum limit.",
        "positive": "Pfaffian particles and strings in SO(2N) gauge theories: We introduce (generalised) Pfaffian operators into our lattice calculations\nof the mass spectra and confining string tensions of SO(2N) gauge theories,\ncomplementing the conventional trace operators used in previous lattice\ncalculations. In SO(6) the corresponding `Pfaffian' particles match the\nnegative charge conjugation particles of SU(4), thus resolving a puzzle arising\nfrom the observation that SO(6) and SU(4) have the same Lie algebra. The same\nholds true (but much more trivially) for SO(2) and U(1). For SO(4) the Pfaffian\nparticles are degenerate with, but orthogonal to, those obtained with the usual\nsingle trace operators. That is to say, there is a doubling of the spectrum, as\none might expect given that the Lie algebra of SO(4) is the same as that of\nSU(2)xSU(2). Additional SO(8) and SO(10) calculations of the Pfaffian spectrum\nconfirm the naive expectation that these masses increase with N, so that they\ncease to play a role in the physics of SO(N) gauge theories as N-->oo. We also\ncalculate the energies of Pfaffian `strings' in these gauge theories. Although\nall our lattice calculations are for gauge theories in D=2+1, similar\nconclusions should hold for D=3+1."
    },
    {
        "anchor": "Exact results for two-color QCD at low and high density: We discuss a random matrix theory that was originally constructed to describe\ntwo-color QCD at low density in the phase with a nonzero chiral condensate.\nWith a particular choice of a parameter, the same random matrix theory also\ndescribes the high-density phase of two-color QCD. In this phase a BCS\nsuperfluid of diquark pairs is formed, and the pattern of chiral symmetry\nbreaking is very different from that at low density. Analytical results for the\nspectral density obtained from this random matrix theory allow for the\nextraction of the BCS gap from lattice data.",
        "positive": "QCD phase diagram: an overview: The aim of this review is to summarize the contemporary understanding of the\nQCD phase diagram as a function of temperature and baryo-chemical potential.\nThe focus is on recent theoretical developments due to lattice simulations of\nthe phase diagram."
    },
    {
        "anchor": "Discriminating between two reformulations of SU(3) Yang-Mills theory on\n  a lattice: In oder to investigate quark confinement, we give a new reformulation of the\n$SU(N)$ Yang-Mills theory on a lattice and present the results of the numerical\nsimulations of the $SU(3)$ Yang-Mills theory on a lattice. The numerical\nsimulations include the derivation of the linear potential for static\ninterquark potential, i.e., non-vanishing string tension, in which the\n\"Abelian\" dominance and magnetic monopole dominance are established,\nconfirmation of the dual Meissner effect by measuring the chromoelectric flux\ntube between quark-antiquark pair, the induced magnetic-monopole current, and\nthe type of dual superconductivity, etc.",
        "positive": "Influence of the Measure on Simplicial Quantum Gravity in Four\n  Dimensions: We investigate the influence of the measure in the path integral for\nEuclidean quantum gravity in four dimensions within the Regge calculus. The\naction is bounded without additional terms by fixing the average lattice\nspacing. We set the length scale by a parameter $\\beta$ and consider a scale\ninvariant and a uniform measure. In the low $\\beta$ region we observe a phase\nwith negative curvature and a homogeneous distribution of the link lengths\nindependent of the measure. The large $\\beta$ region is characterized by\ninhomogeneous link lengths distributions with spikes and positive curvature\ndepending on the measure."
    },
    {
        "anchor": "Heavy-heavy-light quark potential in SU(3) lattice QCD: We perform the first study for the heavy-heavy-light quark (QQq) potential in\nSU(3) lattice QCD. The calculations are done with the standard gauge and\n$O(a)$-improved Wilson fermion action on the $16^4$ lattice at $\\beta =6.0$ at\nthe quenched level. We calculate the energy of QQq systems as the function of\nthe distance between the two heavy quarks, and find that the QQq potential is\nwell described with a Coulomb plus linear potential form. Compared to the\nstatic three-quark case, the Coulomb term does not change but the effective\nstring tension between the heavy quarks is significantly reduced by the\nlight-quark effect. We also investigate the light-quark mass dependence of the\nQQq potential using the four hopping parameters, $\\kappa\n=0.1200,0.1300,0.1340$, and 0.1380. The reduction of the effective string\ntension is considered to be a general property for baryons and multi-quark\nhadrons.",
        "positive": "Another Look at Neural Multigrid: We present a new multigrid method called neural multigrid which is based on\njoining multigrid ideas with concepts from neural nets. The main idea is to use\nthe Greenbaum criterion as a cost functional for the neural net. The algorithm\nis able to learn efficient interpolation operators in the case of the ordered\nLaplace equation with only a very small critical slowing down and with a\nsurprisingly small amount of work comparable to that of a Conjugate Gradient\nsolver. In the case of the two-dimensional Laplace equation with SU(2) gauge\nfields at beta=0 the learning exhibits critical slowing down with an exponent\nof about z = 0.4. The algorithm is able to find quite good interpolation\noperators in this case as well. Thereby it is proven that a practical true\nmultigrid algorithm exists even for a gauge theory. An improved algorithm using\ndynamical blocks that will hopefully overcome the critical slowing down\ncompletely is sketched."
    },
    {
        "anchor": "One-loop lattice artifacts of a dynamical charm quark: For a few observables in O(a) improved lattice QCD, we compute discretization\neffects arising from the vacuum polarization of a heavy quark at one-loop\norder. In particular, the force between static quarks, the running coupling in\nthe Schrodinger functional and a related quantity, {\\bar \\upsilon}, are\nconsidered. Results show that the cutoff effects of a dynamical charm quark are\ntypically smaller than those present in the pure gauge theory. This\nperturbative result is a good indication that dynamical charm quarks are\nfeasible already now.",
        "positive": "Continuum Limits and Exact Finite-Size-Scaling Functions for\n  One-Dimensional $O(N)$-Invariant Spin Models: We solve exactly the general one-dimensional $O(N)$-invariant spin model\ntaking values in the sphere $S^{N-1}$, with nearest-neighbor interactions, in\nfinite volume with periodic boundary conditions, by an expansion in\nhyperspherical harmonics. The possible continuum limits are discussed for a\ngeneral one-parameter family of interactions, and an infinite number of\nuniversality classes is found. For these classes we compute the\nfinite-size-scaling functions and the leading corrections to finite-size\nscaling. A special two-parameter family of interactions (which includes the\nmixed isovector/isotensor model) is also treated, and no additional\nuniversality classes appear. In the appendices we give new formulae for the\nClebsch-Gordan coefficients and 6--$j$ symbols of the $O(N)$ group, and some\nnew generalizations of the Poisson summation formula; these may be of\nindependent interest."
    },
    {
        "anchor": "Spectral functions at non-zero momentum in hot QCD: We present results for meson spectral functions at non-zero momentum at\ntemperatures both below and above Tc, obtained in quenched simulations for a\nnumber of valence quark masses. For the lightest quark masses, a clear\ndifference between the spectral functions on cold and hot lattices is observed.",
        "positive": "Topology and axions in QCD: QCD axions are at the crossroads of QCD topology and Dark Matter searches. We\npresent here the current status of topological studies on the lattice, and\ntheir implication on axion physics. We outline the specific challenges posed by\nlattice topology, the different proposals for handling them, the observable\neffects of topology on the QCD spectrum and its interrelation with chiral and\naxial symmetries. We review the transition to the Quark Gluon Plasma, the fate\nof topology at the transition, and the approach to the high temperature limit.\nWe discuss the extrapolations needed to reach the regime of cosmological\nrelevance, and the resulting constraints on the QCD axion."
    },
    {
        "anchor": "Fisher's zeros as boundary of RG flows in complex coupling space: We discuss the possibility of extending the RG flows to complex coupling\nspaces. We argue that the Fisher's zeros are located at the boundary of the\ncomplex basin of attraction of IR fixed points. We support this picture with\nnumerical calculations at finite volume for2D O(N) models in the large-N limit\nand the hierarchical Ising model using the two-lattice matching method. We\npresent numerical evidence supporting the idea that, as the volume increases,\nthe Fisher's zeros of 4-dimensional pure gauge SU(2) lattice gauge theory with\na Wilson action, stabilize at a distance larger than 0.1 from the real axis in\nthe complex beta=4/g^2 plane. We show that when a positive adjoint term is\nadded, the zeros get closer to the real axis. We compare the situation with the\nU(1) case. We discuss the implications of this new framework for proofs of\nconfinement and searches for nontrivial IR fixed points in models beyond the\nstandard model.",
        "positive": "Probing finite size effects in $(\u03bb\u03a6^4)_4$ MonteCarlo\n  calculations: The Constrained Effective Potential (CEP) is known to be equivalent to the\nusual Effective Potential (EP) in the infinite volume limit. We have carried\nout MonteCarlo calculations based on the two different definitions to get\ninformations on finite size effects. We also compared these calculations with\nthose based on an Improved CEP (ICEP) which takes into account the finite size\nof the lattice. It turns out that ICEP actually reduces the finite size effects\nwhich are more visible near the vanishing of the external source."
    },
    {
        "anchor": "Lepton anomalous magnetic moments in Lattice QCD+QED: We present a lattice calculation of the Hadronic Vacuum Polarization (HVP)\ncontribution to the anomalous magnetic moments of the electron, $a_e^{\\rm\nHVP}$, the muon, $a_\\mu^{\\rm HVP}$, and the tau, $a_\\tau^{\\rm HVP}$, including\nboth the isospin-symmetric QCD term and the leading-order strong and\nelectromagnetic isospin-breaking corrections. Moreover, the contribution to\n$a_\\mu^{\\rm HVP}$ not covered by the MUonE experimen, $a_{MUonE}^{\\rm HVP}$, is\nprovided. We get $a_e^{\\rm HVP} = 185.8~(4.2) \\cdot 10^{-14}$, $a_\\mu^{\\rm HVP}\n= 692.1~(16.3) \\cdot 10^{-10}$, $a_\\tau^{\\rm HVP} = 335.9~(6.9) \\cdot 10^{-8}$\nand $a_{MUonE}^{\\rm HVP} = 91.6~(2.0) \\cdot 10^{-10}$. Our results are obtained\nin the quenched-QED approximation using the QCD gauge configurations generated\nby the European (now Extended) Twisted Mass Collaboration (ETMC) with\n$N_f=2+1+1$ dynamical quarks, at three values of the lattice spacing varying\nfrom $0.089$ to $0.062$ fm, at several values of the lattice spatial size ($L\n\\simeq 1.8 \\div 3.5$ fm) and with pion masses in the range between $\\simeq 220$\nand $\\simeq 490$ MeV.",
        "positive": "The Taming of QCD by Fortran 90: We implement lattice QCD using the Fortran 90 language. We have designed\nmachine independent modules that define fields (gauge, fermions, scalars,\netc...) and have defined overloaded operators for all possible operations\nbetween fields, matrices and numbers. With these modules it is very simple to\nwrite QCD programs. We have also created a useful compression standard for\nstoring the lattice configurations, a parallel implementation of the random\ngenerators, an assignment that does not require temporaries, and a machine\nindependent precision definition. We have tested our program on parallel and\nsingle processor supercomputers obtaining excellent performances."
    },
    {
        "anchor": "A proposal for B-physics on current lattices: A method to extract B-physics parameters (b-quark mass and fB, fBs decay\nconstants) from currently available lattice data is presented and tested. The\napproach is based on the idea of constructing appropriate ratios of heavy-light\nmeson masses and decay constants, respectively, possessing a precisely known\nstatic limit, and evaluating them at various pairs of heavy quark masses around\nthe charm. Via a smooth interpolation in the heavy quark mass from the easily\naccessible charm region to the asymptotic point, B-physics parameters are\ncomputed with a few percent (statistical + systematic) error using recently\nproduced Nf=2 maximally twisted Wilson fermions data.",
        "positive": "Targeting the conformal window with 4+8 flavors: We study the transition between spontaneous chiral symmetry breaking and\nconformal behavior in the SU(3) theory with multiple fermion flavors. Instead\nof the traditional approach of changing the number of flavors, we keep the\nnumber of fermions fixed but lift the mass of a subset, keeping the remaining\nfermions near to the massless chiral limit. This way we can interpolate\ncontinuously between the conformal and chirally broken dynamics. In particular,\nwe consider four light and eight heavy flavors and investigate the\nrunning/walking gauge coupling and the low energy meson spectrum, including the\n0++ iso-singlet scalar state in this system. Our preliminary data reveal an\niso-singlet scalar that is considerably lighter than the pion at large fermion\nmass but becomes heavier at smaller masses. This behavior is of particular\nphenomenological interest."
    },
    {
        "anchor": "Lowest eigenvalues of the Dirac operator for two color QCD at finite\n  density: We investigate the eigenvalue spectrum of the staggered Dirac matrix in full\nQCD with two colors and finite chemical potential. Along the strong-coupling\naxis up to the temperature phase transition, the low-lying Dirac spectrum is\nwell described by random matrix theory (RMT) and exhibits universal behavior.\nThe situation is discussed in the chirally symmetric phase and no universality\nis seen for the microscopic spectral density.",
        "positive": "Disconnected Loop Subtraction Methods in Lattice QCD: Lattice QCD calculations of disconnected quark loop operators are extremely\ncomputer time-consuming to evaluate. To compute these diagrams using lattice\ntechniques, one generally uses stochastic noise methods. These employ a\nrandomly generated set of noise vectors to project out physical signals. In\norder to strengthen the signal in these calculations, various noise subtraction\ntechniques may be employed. In addition to the standard method of perturbative\nsubtraction, one may also employ matrix deflation techniques using the GMRES-DR\nand MINRES-DR algorithms as well as polynomial subtraction techniques to reduce\nstatistical uncertainty. Our matrix deflation methods play two roles: they both\nspeed up the solution of the linear equations as well as decrease numerical\nnoise. We show how to combine deflation with either perturbative and polynomial\nmethods to produce extremely powerful noise suppression algorithms. We use a\nvariety of lattices to study the effects. In order to set a benchmark, we first\nuse the Wilson matrix in the quenched approximation. We see strong low\neigenmode dominance at kappa critical ($\\kappa_{crit}$) in the variance of the\nvector and scalar operators. We also use MILC dynamic lattices, where we\nobserve deflation subtraction results consistent with the effectiveness seen in\nthe quenched data."
    },
    {
        "anchor": "Magnetic properties of the nucleon in a uniform background field: We present results for the magnetic moment and magnetic polarisability of the\nneutron and the magnetic moment of the proton. These results are calculated\nusing the uniform background field method on 32^3 x 64 dynamical QCD lattices\nprovided by the PACS-CS collaboration as part of the ILDG. We use a uniform\nbackground magnetic field quantised by the periodic spatial volume. We\ninvestigate ways to improve the effective energy plots used to calculate\nmagnetic polarisabilities, including the use of correlation matrix techniques\nwith various source smearings.",
        "positive": "Staggered eigenvalue mimicry: We study the infrared part of the spectrum for UV-filtered staggered Dirac\noperators and compare them to the overlap counterpart. With sufficient\nfiltering and at small enough lattice spacing the staggered spectra manage to\n``mimic'' the overlap version. They show a 4-fold near-degeneracy, and a clear\nseparation between would-be zero modes and non-zero modes. This suggests an\napproximate index theorem for filtered staggered fermions and a correct\nsensitivity to the topology of QCD. Moreover, it supports square-rooting the\nstaggered determinant to obtain dynamical ensembles with $N_f=2$."
    },
    {
        "anchor": "Real-space blocking of qubit variables on parallel lattice gauge theory\n  links for quantum simulation: One of the methods proposed in the last years for studying non-perturbative\ngauge theory physics is quantum simulation, where lattice gauge theories are\nmapped onto quantum devices which can be built in the laboratory, or quantum\ncomputers. While being very promising and already showing some experimental\nresults, these methods still face several challenges related to the interface\nbetween the technological capabilities and the demands of the simulated models;\nin particular, one such challenge is the need to simulate infinitely\ndimensional local Hilbert spaces, describing the gauge fields on the links in\nthe case of compact Lie gauge groups, requiring some truncations and\napproximations which are not completely understood or controllable in the\ngeneral case. This work proposes a way to obtain arbitrarily large such local\nHilbert spaces by using coarse graining of simple, low dimensional qubit\nsystems, made of components available on most quantum simulation platforms, and\nthus opening the way of new types of lattice gauge theory quantum simulations.",
        "positive": "Accessing scattering amplitudes using quantum computers: Future quantum computers may serve as a tool to access non-perturbative\nreal-time correlation functions. In this talk, we discuss the prospects of\nusing these to study Compton scattering for arbitrary kinematics. The\nrestriction to a finite-volume spacetime, unavoidable in foreseeable\nquantum-computer simulations, must be taken into account in the formalism for\nextracting scattering observables. One approach is to work with a non-zero $i\n\\epsilon$-prescription in the Fourier transform to definite momentum and then\nto estimate an ordered double limit, in which the spacetime volume is sent to\ninfinity before $\\epsilon$ is sent to $0$. For the amplitudes and parameters\nconsidered here, we find that significant volume effects arise, making the\nrequired limit very challenging. We present a practical solution to this\nchallenge that may allow for future determinations of deeply virtual Compton\nscattering amplitudes, as well as many other reactions that are presently\noutside the scope of standard lattice QCD calculations."
    },
    {
        "anchor": "Spectral densities from the lattice: We discuss a method to extract the K\\\"all\\'{e}n-Lehmann spectral density of a\nparticle (be it elementary or bound state) propagator by means of 4d lattice\ndata. We employ a linear regularization strategy, commonly known as the\nTikhonov method with Morozov discrepancy principle. An important virtue over\nthe popular maximum entropy method is the possibility to also probe unphysical\nspectral densities, as, for example, of a confined gluon. We apply our proposal\nto the SU(3) glue sector.",
        "positive": "A light composite scalar in eight-flavor QCD on the lattice: In search for a composite Higgs boson (techni-dilaton) in the walking\ntechnicolor, we present our preliminary results on the first observation of a\nlight flavor-singlet scalar in a candidate theory for the walking technicolor,\nthe Nf=8 QCD, which was found in our previous paper to have spontaneous chiral\nsymmetry breaking together with remnants of the conformality. Based on\nsimulations with the HISQ-type action on several lattice sizes with various\nfermion masses, we find evidence of a flavor-singlet scalar meson with mass\ncomparable to that of the Nambu-Goldstone pion in both the small fermion-mass\nregion, where chiral perturbation theory works, and the intermediate\nfermion-mass region where the hyperscaling relation holds. We further discuss\nits chiral limit extrapolation in comparison with other states studied in our\nprevious paper: the scalar has a mass much smaller than that of the vector\nmeson, which is compared to the Nambu-Goldstone pion having a vanishing mass in\nthat limit."
    },
    {
        "anchor": "Simulating the All-Order Strong Coupling Expansion III: O(N) sigma/loop\n  models: We reformulate the O(N) sigma model as a loop model whose configurations are\nthe all-order strong coupling graphs of the original model. The loop\nconfigurations are represented by a pointer list in the computer and a Monte\nCarlo update scheme is proposed. Sample simulations are reported and the method\nturns out to be similarly efficient as the reflection cluster method, but it\nhas greater potential for systematic generalization to other lattice field\ntheories. A variant action suggested by the method is also simulated and leads\nto a rather extreme demonstration of the concept of universality of the scaling\nor continuum limit.",
        "positive": "Testing the chiral behavior of the hadron spectrum: We analyze the chiral behavior of the hadron spectrum obtained with quenched\nWilson fermions on 170 $32^3 \\times 64$ lattices at $\\beta = 6.0$. We calculate\nmasses of hadrons composed of both degenerate and non-degenerate quarks. We\nreduce the statistical errors in mass splittings by directly fitting to the\nratio of correlation functions. We find significant deviations from a linear\ndependence on the quark mass, deviations that are consistent with the higher\norder terms predicted by quenched chiral perturbation theory. Including these\ncorrections yields splittings in the baryon octet that agree with those\nobserved experimentally. Smaller higher order terms are also present in\n$m_\\rho$ and $m_N$. By contrast, the decuplet baryons are well described by a\nlinear mass term. We find the decuplet splittings to be 30% smaller than\nexperiment. We extrapolate our data to $a \\to 0$ by combining with the GF11\nresults, and the best fit suggests that the quenched approximation is only good\nto $10-15%$."
    },
    {
        "anchor": "Topology, Random Matrix Theory and the spectrum of the Wilson Dirac\n  operator: We study the spectrum of the hermitian Wilson Dirac operator in the\nepsilon-regime of QCD in the quenched approximation and compare it to\npredictions from Wilson Random Matrix Theory. Using the distributions of single\neigenvalues in the microscopic limit and for specific topological charge\nsectors, we examine the possibility of extracting estimates of the low energy\nconstants which parametrise the lattice artefacts in Wilson chiral perturbation\ntheory. The topological charge of the field configurations is obtained from a\nfield theoretical definition as well as from the flow of eigenvalues of the\nhermitian Wilson Dirac operator, and we determine the extent to which the two\nare correlated.",
        "positive": "An Improved Acceptance Procedure for the Hybrid Monte Carlo Algorithm: The probability of accepting a candidate move in the hybrid Monte Carlo\nalgorithm can be increased by considering a transition to be between windows of\nseveral states at the beginning and end of the trajectory, with a state within\nthe selected window being chosen according to the Boltzmann probabilities. The\ndetailed balance condition used to justify the algorithm still holds with this\nprocedure, provided the start state is randomly positioned within its window.\nThe new procedure is shown empirically to significantly improve performance for\na test system of uncoupled oscillators."
    },
    {
        "anchor": "Continuum limit of SU(3) $\\mathcal{N}=1$ supersymmetric Yang-Mills\n  theory and supersymmetric gauge theories on the lattice: We summarize our investigations of several aspects of $\\mathcal{N}=1$\nsupersymmetric Yang-Mills (SYM) theory. We present our final results for SU(3)\n$\\mathcal{N}=1$ SYM simulated with Wilson fermions. We also discuss the first\ntest of the simulations of the theory with overlap gluinos. Finally, we present\nsome recent progresses concerning the phase structure of the compactified\ntheory on $R^3\\times S^1$.",
        "positive": "A microscopic semiclassical confining field equation for $U(1)$ lattice\n  gauge theory in 2+1 dimensions: We present a semiclassical nonlinear field equation for the confining field\nin 2+1--dimensional $U(1)$ lattice gauge theory (compact QED). The equation is\nderived directly from the underlying microscopic quantum Hamiltonian by means\nof truncation. Its nonlinearities express the dynamic creation of magnetic\nmonopole currents leading to the confinement of the electric field between two\nstatic electric charges. We solve the equation numerically and show that it can\nbe interpreted as a London relation in a dual superconductor."
    },
    {
        "anchor": "Prediction of Peptide Conformation by Multicanonical Algorithm: A New\n  Approach to the Multiple-Minima Problem: We apply a recently developed method, multicanonical algorithm, to the\nproblem of tertiary structure prediction of peptides and proteins. As a simple\nexample to test the effectiveness of the algorithm, Met-enkephalin is studied\nand the ergodicity problem, or multiple-minima problem, is shown to be overcome\nby this algorithm. The lowest-energy conformation obtained agrees with that\ndetermined by other efficient methods such as Monte Carlo simulated annealing.\nThe superiority of the present method to simulated annealing lies in the fact\nthat the relationship to the canonical ensemble remains exactly controlled.\nOnce the multicanonical parameters are determined, only one simulation run is\nnecessary to obtain the lowest-energy conformation and furthermore the results\nof this one run can be used to calculate various thermodynamic quantities at\nany temperature. The latter point is demonstrated by the calculation of the\naverage potential energy and specific heat as functions of temperature.",
        "positive": "Composite Weak Bosons: a Lattice Monte Carlo Analysis: We present a lattice Monte Carlo simulation for the evaluation of the\nspectrum of a confining Yang-Mills theory without Goldstone boson. We show that\nthis theory is a very good candidate for describing composite weak bosons. In\norder to perform the spectrum analysis we have used standard lattice QCD Monte\nCarlo methods. We have also developed an efficient method to evaluate the mass\nof the pseudoscalar isosinglet which is present in our theory."
    },
    {
        "anchor": "Critical couplings and string tensions from two-lattice matching of RG\n  decimations: Critical couplings and string tensions in SU(2) and SU(3) lattice gauge\ntheory are calculated by two-lattice matching of RG block transformations. The\ntransformations are of the potential moving type generating plaquette actions\nwith large number of group characters and exhibit rapid approach to a unique\nrenormalized trajectory. Fixing the critical coupling $\\beta(N_\\tau)$ at one\nvalue of temporal lattice extent $N_\\tau$ by MC simulation, the critical\ncouplings for other values of $N_\\tau$ are then obtained by lattice matching of\nthese decimations. $\\beta(N_\\tau)$ values are thus obtained for a range of\n$N_\\tau$ and found to be in agreement with MC simulation results to within a\nfew percent in all cases. A similar procedure allows the calculation of string\ntensions for a range of $\\beta$ values with similarly good agreement with MC\ndata.",
        "positive": "On the quality of random number generators with taps: Recent exact analytical results developed for the random number generators\nwith taps are reported. These results are applicable to a wide class of\nalgorithms, including random walks, cluster algorithms, Ising models. Practical\nconsiderations on the improvement of the quality of random numbers are\ndiscussed as well."
    },
    {
        "anchor": "On the order of the deconfining transition in N_f=2 QCD: A careful study is made on the lattice of the phase diagram of QCD with two\nstaggered flavors, to investigate the order of the chiral transition of N_f=2\nQCD. The specific heat and the susceptibility of the chiral condensate are\ndetermined for different spatial sizes of the system, and a finite size scaling\nanalysis provides a determination of the (pseudo)critical indices. The result\nis a strong indication that the chiral transition is first order.",
        "positive": "Finite volume effects in SU(2) with two adjoint fermions: Many evidences from lattice simulations support the idea that SU(2) with two\nDirac flavors in the adjoint representation (also called Minimal Walking\nTechnicolor) is IR conformal. A possible way to see this is through the\nbehavior of the spectrum of the mass-deformed theory. When fermions are\nmassive, a mass-gap is generated and the theory is confined. IR-conformality is\nrecovered in the chiral limit: masses of particles vanish in the chiral limit,\nwhile their ratios stay finite. In order to trust this analysis one has to\nrelay on the infinite volume extrapolation. We will discuss the finite volume\neffects on the mesonic spectrum, investigated by varying the size of the\nlattice and by changing the boundary conditions for the fields."
    },
    {
        "anchor": "Thermal Transitions in Dense Two-Colour QCD: The infamous sign problem makes it impossible to probe dense (baryon density\n$\\mu_B>0$) QCD at temperatures near or below the deconfinement threshold. As a\nworkaround, one can explore QCD-like theories such as two-colour QCD (QC2D)\nwhich don't suffer from this sign problem but are qualitively similar to real\nQCD. Previous studies on smaller lattice volumes have investigated\ndeconfinement and colour superfluid to normal matter transitions. In this study\nwe look at a larger lattice volume $N_s=24$ in an attempt to disentangle finite\nvolume and finite temperature effects. We also fit to a larger number of\ndiquark sources to better allow for extrapolation to zero diquark source.",
        "positive": "Instantons and the fixed point topological charge in the two-dimensional\n  O(3) sigma-model: We define a fixed point topological charge for the two-dimensional O(3)\nlattice sigma-model which is free of topological defects. We use this operator\nin combination with the fixed point action to measure the topological\nsusceptibility for a wide range of correlation lengths. The results strongly\nsuggest that it is not a physical quantity in this model. The procedure,\nhowever, can be applied to other asymptotically free theories as well."
    },
    {
        "anchor": "U_A(1) breaking at finite temperature from the Dirac spectrum with the\n  dynamical HISQ action: We investigate $U_A(1)$ breaking above $T_c$ in terms of the Dirac spectrum\non configurations with (2+1)-flavors, using the HISQ action. The strange quark\nmass is at its physical value. We use several light quark masses corresponding\nto the Goldstone pion masses in the range of about 115 -- 230 MeV on lattices\nof size 32$^3 \\times$8 and 48$^3 \\times$8. We calculate the 100 lowest-lying\nDirac eigenvalues at temperatures below and above $T_c$. We investigate the\nvolume dependence of the Dirac eigenvalue density to determine whether there is\na gap around zero, which can appear if $U_A(1)$ symmetry is restored in the\nchiral symmetric phase. We also investigate the quark mass dependence of the\nDirac eigenvalue density at zero and check whether there is a linear behavior\nthat would signal the $U_A(1)$ breaking above $T_c$.",
        "positive": "More about the axial anomaly on the lattice: We study the axial anomaly defined on a finite-size lattice by using a Dirac\noperator which obeys the Ginsparg-Wilson relation. When the gauge group is\nU(1), we show that the basic structure of axial anomaly on the infinite\nlattice, which can be deduced by a cohomological analysis, persists even on\n(sufficiently large) finite-size lattices. For non-abelian gauge groups, we\npropose a conjecture on a possible form of axial anomaly on the infinite\nlattice, which holds to all orders in perturbation theory. With this\nconjecture, we show that a structure of the axial anomaly on finite-size\nlattices is again basically identical to that on the infinite lattice. Our\nanalysis with the Ginsparg-Wilson Dirac operator indicates that, in appropriate\nframeworks, the basic structure of axial anomaly is quite robust and it\npersists even in a system with finite ultraviolet and infrared cutoffs."
    },
    {
        "anchor": "Connected and Disconnected Contractions in Pion-Pion Scattering: We show that the interplay of chiral effective field theory and lattice QCD\ncan be used in the evaluation of so-called disconnected diagrams, which appear\nin the study of the isoscalar and isovector channels of pion-pion scattering\nand have long been a major challenge for the lattice community. By means of\npartially-quenched chiral perturbation theory, we distinguish and analyze the\neffects from different types of contraction diagrams to the pion-pion\nscattering amplitude, including its scattering lengths and the\nenergy-dependence of its imaginary part. Our results may be used to test the\ncurrent degree of accuracy of lattice calculation in the handling of\ndisconnected diagrams, as well as to set criteria for the future improvement of\nrelevant lattice computational techniques that may play a critical role in the\nstudy of other interesting QCD matrix elements.",
        "positive": "Domain Wall QCD with Near-Physical Pions: We present physical results for a variety of light hadronic quantities\nobtained via a combined analysis of three 2+1 flavour domain wall fermion\nensemble sets. For two of our ensemble sets we used the Iwasaki gauge action\nwith beta=2.13 (a^-1=1.75(4) GeV) and beta=2.25 (a^-1=2.31(4) GeV) and lattice\nsizes of 24^3 x 64 and 32^3 x 64 respectively, with unitary pion masses in the\nrange 293(5)-417(10) MeV. The extent L_s for the 5^th dimension of the domain\nwall fermion formulation is L_s=16 in these ensembles. In this analysis we\ninclude a third ensemble set that makes use of the novel Iwasaki+DSDR\n(Dislocation Suppressing Determinant Ratio) gauge action at beta = 1.75\n(a^-1=1.37(1) GeV) with a lattice size of 32^3 x 64 and L_s=32 to reach down to\npartially-quenched pion masses as low as 143(1) MeV and a unitary pion mass of\n171(1) MeV, while retaining good chiral symmetry and topological tunneling. We\ndemonstrate a significant improvement in our control over the chiral\nextrapolation, resulting in much improved continuum predictions for the above\nquantities. The main results of this analysis include the pion and kaon decay\nconstants, f_\\pi=127(3)_{stat}(3)_{sys} MeV and f_K = 152(3)_{stat}(2)_{sys}\nMeV respectively (f_K/f_\\pi = 1.199(12)_{stat}(14)_{sys}); the average up/down\nquark mass and the strange-quark mass in the MSbar-scheme at 3 GeV,\nm_{ud}(MSbar, 3 GeV) = 3.05(8)_{stat}(6)_{sys} MeV and m_s(MSbar, 3 GeV) =\n83.5(1.7)_{stat}(1.1)_{sys}; the neutral kaon mixing parameter in the\nMSbar-scheme at 3 GeV, B_K(MSbar,3 GeV) = 0.535(8)_{stat}(13)_{sys}, and in the\nRGI scheme, \\hat B_K = 0.758(11)_{stat}(19)_{sys}; and the Sommer scales r_1 =\n0.323(8)_{stat}(4)_{sys} fm and r_0 = 0.480(10)_{stat}(4)_{sys} (r_1/r_0 =\n0.673(11)_{stat}(3)_{sys}). We also obtain values for the SU(2) ChPT effective\ncouplings, \\bar{l_3} = 2.91(23)_{stat}(7)_{sys}$ and \\bar{l_4} =\n3.99(16)_{stat}(9)_{sys}."
    },
    {
        "anchor": "Gauge-independent \"Abelian\" and magnetic-monopole dominance, and the\n  dual Meissner effect in lattice $SU(2)$ Yang-Mills theory: In the $SU(2)$ Yang-Mills theory on the four-dimensional Euclidean lattice,\nwe confirm the gauge-independent \"Abelian\" dominance (or the restricted field\ndominance) and gauge-independent magnetic-monopole dominance in the string\ntension of the linear potential extracted from the Wilson loop in the\nfundamental representation. The dual Meissner effect is observed by\ndemonstrating the squeezing of the chromoelectric field flux connecting a pair\nof quark and antiquark. In addition, the circular magnetic-monopole current is\ninduced around the chromoelectric flux. The type of the dual superconductivity\nis also determined by fitting the result with the dual Ginzburg-Landau model.\nThus the dual superconductor picture for quark confinement is supported in a\ngauge-independent manner. These results are obtained based on a reformulation\nof the lattice Yang-Mills theory based on the change of variables a la\nCho-Duan-Ge-Faddeev-Niemi combined with a non-Abelian Stokes theorem for the\nWilson loop operator. We give a new procedure (called the reduction) for\nobtaining the color direction field which plays the central role in this\nreformulation.",
        "positive": "On-shell and off-shell improvement for Ginsparg-Wilson fermions: We discuss the improvement of bilinear fermionic operators for\nGinsparg-Wilson fermions. We present explicit formulae for improved Green's\nfunctions, which apply both on-shell and off-shell."
    },
    {
        "anchor": "Finite size scaling and the effect of the gauge coupling in 12 flavor\n  systems: Finite size scaling is a powerful tool to study the critical properties of\nsystems governed by one relevant operator, assuming all irrelevant operators\nhave scaling dimensions much smaller then zero. This condition is likely not\nsatisfied in many-fermion conformal systems where perturbation theory predicts\na nearly-marginal irrelevant gauge coupling. In this work we carry out a new\ninvestigation of SU(3) lattice gauge theory with 12 fundamental flavors.\nAnalyzing data at many different gauge couplings, our preliminary results\nindicate that a finite size scaling analysis that takes into account the effect\nof a nearly-marginal gauge coupling can resolve many of the inconsistencies\nobserved previously in this system, leading to results consistent with\nconformal infrared dynamics and predicting a mass scaling anomalous around\n$\\gamma_m=0.25$.",
        "positive": "Open Science in Lattice Gauge Theory community: Open science aims to make scientific research processes, tools and results\naccessible to all scientific communities, creating trust in science and\nenabling digital competences to be realized in research, leading to increased\ninnovation. It provides standard and transparent pathways to conducting\nresearch and fosters best practices for collecting, analysing, preserving,\nsharing and reusing data, software, workflows and other outputs through\ncollaborative networks. Open Science appears to be becoming the norm with its\napplications spanning throughout the whole research cycle of a project. The\nimportance of making Open Science a reality is nowadays reflected in funding\npolicies, research infrastructure and politics. In these proceedings we present\nthe basic Open Science principles explaining briefly best practices for\nmaterialising Open Science. Subsequently, we present the results of the\nlandscaping survey of Open Science in the Lattice Gauge Theories community.\nFinally, we provide directions in which the Lattice Gauge Theory community\ncould move in order to enhance Openness and FAIRness (Findability,\nAccessibility, Interoperability, Reusability) in Science."
    },
    {
        "anchor": "Weak matrix elements and K-meson physics: An overview is presented about old and recent methods to compute the $K\\to\n\\pi \\pi$ decay amplitude.",
        "positive": "Non-perturbative singularity structure of gluon and quark propagators: A gauge invariant, non-local observable is constructed in lattice pure gauge\ntheory, which is identical to the gluon propagator in a particular gauge. The\ntransfer matrix formalism is used to show that this correlator decays\nexponentially with eigenvalues of the Hamiltonian. This implies a gauge\ninvariant singularity structure of the propagator in momentum space, permitting\na non-perturbative definition of a parton mass. The relation to gauge fixing\nand the extension to matter fields are discussed."
    },
    {
        "anchor": "Chiral Lattice Gauge Theories Via Mirror-Fermion Decoupling: A Mission\n  (im)Possible?: This is a review of the status and outstanding issues in attempts to\nconstruct chiral lattice gauge theories by decoupling the mirror fermions from\na vectorlike theory. In the first half, we explain why studying nonperturbative\nchiral gauge dynamics may be of interest, enumerate the problems that a lattice\nformulation of chiral gauge theories must overcome, and briefly review our\ncurrent knowledge. We then discuss the motivation and idea of mirror-fermion\ndecoupling and illustrate the desired features of the decoupling dynamics by a\nsimple solvable toy model. The role of exact chiral symmetries and matching of\n't Hooft anomalies on the lattice is also explained. The second, more\ntechnical, half of the article is devoted to a discussion of the known and\nunknown features of mirror-decoupling dynamics formulated with Ginsparg-Wilson\nfermions. We end by pointing out possible directions for future studies.",
        "positive": "Hadron masses and decay constants in quenched QCD: We present results for the mass spectrum and decay constants using\nnon-perturbatively O(a) improved Wilson fermions. Three values of $\\beta$ and\n30 different quark masses are used to obtain the chiral and continuum limits.\nSpecial emphasis will be given to the question of taking the chiral limit and\nthe existence of non-analytic behavior predicted by quenched chiral\nperturbation theory."
    },
    {
        "anchor": "Strangeness Contribution to the Proton Spin from Lattice QCD: We compute the strangeness and light-quark contributions Delta s, Delta u and\nDelta d to the proton spin in nf=2 lattice QCD at a pion mass of about 285 MeV\nand at a lattice spacing a approx 0.073 fm, using the non-perturbatively\nimproved Sheikholeslami-Wohlert Wilson action. We carry out the renormalization\nof these matrix elements which involves mixing between contributions from\ndifferent quark flavours. Our main result is the small negative value MSbar\nscheme value Delta s = -0.020(10)(4), at a scale mu = 7.4 GeV, of the\nstrangeness contribution to the nucleon spin. The second error is an estimate\nof the uncertainty, due to the missing extrapolation to the physical point.",
        "positive": "High-statistics finite size scaling analysis of U(1) lattice gauge\n  theory with Wilson action: We describe the results of a systematic high-statistics Monte-Carlo study of\nfinite-size effects at the phase transition of compact U(1) lattice gauge\ntheory with Wilson action on a hypercubic lattice with periodic boundary\nconditions. We find unambiguously that the critical exponent nu is lattice-size\ndependent for volumes ranging from 4^4 to 12^4. Asymptotic scaling formulas\nyield values decreasing from nu(L >= 4) = 0.33 to nu(L >= 9) = 0.29. Our\nstatistics are sufficient to allow the study of different phenomenological\nscenarios for the corrections to asymptotic scaling. We find evidence that\ncorrections to a first-order transition with nu=0.25 provide the most accurate\ndescription of the data. However the corrections do not follow always the\nexpected first-order pattern of a series expansion in the inverse lattice\nvolume V^{-1}. Reaching the asymptotic regime will require lattice sizes\ngreater than L=12. Our conclusions are supported by the study of many cumulants\nwhich all yield consistent results after proper interpretation."
    },
    {
        "anchor": "Gauge-invariant signatures of spontaneous gauge symmetry breaking by the\n  Hosotani mechanism: The Hosotani mechanism claims to achieve gauge-symmetry breaking, for\ninstance $SU(3) \\to SU(2)\\times U(1)$. To verify this claim, we propose to\nmonitor the stability of a topological defect stable under a gauge subgroup but\nnot under the whole gauge group, like a $U(1)$ flux state or monopole in the\ncase above. We use gauge invariant operators to probe the presence of the\ntopological defect to avoid any ambiguity introduced by gauge fixing. Our\nmethod also applies to an ordinary gauge-Higgs system.",
        "positive": "Unusual Features of QCD Low-Energy Modes in IR Phase: It was recently proposed that there is a phase in thermal QCD (IR phase) at\ntemperatures well above the chiral crossover, featuring elements of scale\ninvariance in the infrared (IR). Here we study the effective spatial\ndimensions, $d_{IR}$, of Dirac low-energy modes in this phase, in the context\nof pure-glue QCD. Our $d_{IR}$ is based on the scaling of mode support toward\nthermodynamic limit, and hence is an IR probe. Ordinary extended modes, such as\nthose at high energy, have $d_{IR}=3$. We find $d_{IR}<3$ in the spectral range\nwhose lower edge coincides with $\\lambda_{IR}=0$, the singularity of spectral\ndensity defining the IR phase, and the upper edge with $\\lambda_A$, the\npreviously identified Anderson-like non-analyticity. Details near\n$\\lambda_{IR}$ are unexpected in that only exact zero modes are $d_{IR}=3$,\nwhile a thin spectral layer near zero is $d_{IR}=2$, followed by an extended\nlayer of $d_{IR}=1$ modes. With only integer values appearing, $d_{IR}$ may\nhave topological origin. We find similar structure at $\\lambda_A$, and\nassociate its adjacent thin layer ($d_{IR} >\\approx 2$) with Anderson-like\ncriticality. Our analysis reveals the manner in which non-analyticities at\n$\\lambda_{IR}$ and $\\lambda_A$, originally identified in other quantities,\nappear in $d_{IR}(\\lambda)$. This dimension structure may be important for\nunderstanding the near-perfect fluidity of the quark-gluon medium seen in\naccelerator experiments. The role of $\\lambda_A$ in previously conjectured\ndecoupling of IR component is explained."
    },
    {
        "anchor": "Kaon Weak Matrix Elements in 2+1 flavor DWF QCD: $K \\to \\pi$ and $K \\to 0$ weak matrix elements of $\\Delta S = 1$ operators\nhave been measured in 2+1 flavor domain wall fermion (DWF) QCD on (3 fm)$^3$\nlattices with $a^{-1} = 1.73(3)$ GeV. As is well known, using these matrix\nelements and chiral perturbation theory allows a determination of the $K \\to\n\\pi \\pi$ matrix elements that enter in the quantitative value for the $\\Delta I\n= 1/2$ rule and $\\epsilon^\\prime/\\epsilon$. Two light dynamical sea quark\nmasses have been used, along with six valence quark masses, with the lightest\nvalence quark mass $\\approx 1/10$ the physical strange quark mass. We report\nour results for lattice matrix elements in the $SU(3)_L \\times SU(3)_R$ (27,1),\n(8,1), and (8,8) representations, paying particular attention to the\nstatistical errors achieved after measurements on 75 configurations. We also\nreport on our calculation of the non-perturbative renormalization coefficients\nfor these $\\Delta S=1$ weak operators, using the Rome-Southampton method.",
        "positive": "Supercurrent renormalization of $\\mathcal{N}=1$ supersymmetric\n  Yang-Mills theory on the lattice: Supersymmetry on the lattice is explicitly broken by the gluino mass and\nlattice artifacts. However, it can be restored in the continuum limit by fine\ntuning the parameters based on the renormalized Ward identities. On the\nrenormalization step not only the mass but also the renormalization of the\nsupercurrent needs to be addressed. Here we present a lattice investigation to\nobtain the renormalization factors of the supercurrent for $\\mathcal{N}$=1\nSuper-Yang Mills theory in a gauge invariant renormalization scheme. We also\nprovide the conversion factors which are necessary in order to translate our\nresults to the more standard $\\overline{\\text{MS}}$ scheme."
    },
    {
        "anchor": "Quark number susceptibility at finite density and low temperature: We study the quark number susceptibility in SU(2) lattice gauge theory with\ntwo Wilson quark flavours at non-zero chemical potential and low temperature.\nWe present some technical aspects of the issue and numerical results obtained\nat different lattices and different parameters. We discuss what this observable\ncan teach us about the phase diagram of the model and in particular about the\nrelation between susceptibility and Polyakov loop",
        "positive": "Topological Visualisation techniques for the understanding of Lattice\n  Quantum Chromodynamics (LQCD) simulations: The use of topology for visualisation applications has become increasingly\npopular due to its ability to summarise data at a high level. Criticalities in\nscalar field data are used by visualisation methods such as the Reeb graph and\ncontour trees to present topological structure in simple graph based formats.\nThese techniques can be used to segment the input field, recognising the\nboundaries between multiple objects, allowing whole contour meshes to be seeded\nas separate objects. In this paper we demonstrate the use of topology based\ntechniques when applied to theoretical physics data generated from Quantum\nChromodynamics simulations, which due to its structure complicates their use.\nWe also discuss how the output of algorithms involved in topological\nvisualisation can be used by physicists to further their understanding of\nQuantum Chromodynamics."
    },
    {
        "anchor": "Centre vortices are the seeds of dynamical chiral symmetry breaking: Using lattice QCD, we reveal a fundamental connection between centre vortices\nand several key features associated with dynamical chiral symmetry breaking and\nquark confinement. Calculations are performed in pure SU(3) gauge theory using\nthe chiral overlap fermion action. Starting from the original Monte Carlo gauge\nfields, a vortex identification procedure yields vortex-removed and vortex-only\nbackgrounds. We examine the static quark potential, the quark mass function,\nthe hadron spectrum, the local topological charge density, and the distribution\nof instanton-like objects on the original, vortex-removed and vortex-only\nensembles. The removal of vortices consistently results in the removal of the\ncorresponding feature associated with dynamical chiral symmetry breaking.\nRemarkably, we observe that after some smoothing, in each of these cases, the\nvortex-only degrees of freedom are able to encapsulate the pertinent features\nof the original gauge fields.",
        "positive": "Another look at the Landau gauge three-gluon vertex: We revisit the computation of the three-gluon vertex in the Landau gauge\nusing lattice QCD simulations with large physical volumes of $\\sim$ (6.5 fm)$^\n4$ and $\\sim$ (8 fm)$^ 4$ and large statistical ensembles. For the kinematical\nconfiguration analysed, that is described by a unique form factor, an\nevaluation of the lattice artefacts is also performed. Particular attention is\ngiven to the low energy behaviour of vertex and its connection with evidence\n(or lack of it) of infrared ghost dominance."
    },
    {
        "anchor": "Advances in the Determination of Quark Masses: Significant progress has been made in the determination of the light quark\nmasses, using both lattice QCD and sum rule methods, in the last year. We\ndiscuss the different methods and review the status of current results.\nFinally, we review the calculations of bottom and charm quark masses.",
        "positive": "Detailed Phase Transition Study at M_H <= 70 GeV in a 3-dimensional\n  $SU(2)$--Higgs Model: We study the electroweak phase transition in an effective 3-dimensional\ntheory for a Higgs mass of about 70 GeV by Monte Carlo simulations. The\ntransition temperature and jumps of order parameters are obtained and\nextrapolated to the continuum using multi-histogram techniques and finite size\nanalysis."
    },
    {
        "anchor": "Topological susceptibility from $N_f=2+1+1$ lattice QCD at nonzero\n  temperature: We present results for the topological susceptibility at nonzero temperature\nobtained from lattice QCD with four dynamical quark flavours. We apply\ndifferent smoothing methods, including gradient Wilson flow and over--improved\ncooling, before calculating the susceptibility. It is shown that the considered\nsmoothing techniques basically agree among each other, and that there are\nsimple scaling relations between flow time and the number of cooling/smearing\nsteps. The topological susceptibility exhibits a surprisingly slow decrease at\nhigh temperature.",
        "positive": "Study of a new simulation algorithm for dynamical quarks on the APE-100\n  parallel computer: First results on the autocorrelation behaviour of a recently proposed fermion\nalgorithm by M. L\\\"uscher are presented and discussed. The occurence of\nunexpected large autocorrelation times is explained. Possible improvements are\ndiscussed."
    },
    {
        "anchor": "Chiral properties of (2+1)-flavor QCD in strong magnetic fields at zero\n  temperature: We present lattice QCD results for masses and magnetic polarizabilities of\nlight and strange pseudoscalar mesons, chiral condensates, decay constants of\nneutral pion, and neutral kaon in the presence of background magnetic fields\nwith $eB$ ranging up to around 3.35 GeV$^2$ ($\\sim70~M_\\pi^2$) in the vacuum.\nThe computations were carried out in (2+1)-flavor QCD mostly on $32^3 \\times\n96$ lattices using the highly improved staggered quark action with $M_{\\pi}\n\\approx $ 220 MeV at zero temperature. We find that the masses of neutral\npseudoscalar mesons monotonously decrease as the magnetic field strength grows\nand then saturate at a nonzero value, while there exists a nonmonotonous\nbehavior of charged pion and kaon masses in the magnetic field. We observe a\n$qB$ scaling of the up and down quark flavor components of neutral pion mass,\nneutral pion decay constant as well as the quark chiral condensates at 0.05\n$\\lesssim eB\\lesssim$ 3.35 GeV$^2$. We show that the correction to the\nGell-Mann-Oakes-Renner relation involving the neutral pion is less than 6% and\nthe correction for the relation involving neutral kaon is less than 30% at\n$eB\\lesssim$ 3.35 GeV$^2$. We also derive the Ward-Takahashi identities for QCD\nin the magnetic field in the continuum formulation including the relation\nbetween integrated neutral pseudoscalar meson correlators and chiral\ncondensates.",
        "positive": "The errant life of a heavy quark in the quark-gluon plasma: In the high-temperature phase of QCD, the heavy quark momentum diffusion\nconstant determines, via a fluctuation-dissipation relation, how fast a heavy\nquark kinetically equilibrates. This transport coefficient can be extracted\nfrom thermal correlators via a Kubo formula. We present a lattice calculation\nof the relevant Euclidean correlators in the gluon plasma, based on a recent\nformulation of the problem in heavy-quark effective field theory (HQET). We\nfind a $\\approx20%$ enhancement of the Euclidean correlator at maximal time\nseparation as the temperature is lowered from $6T_c$ to $2T_c$, pointing to\nstronger interactions at lower temperatures. At the same time, the correlator\nbecomes flatter from $6T_c$ down to $2T_c$, indicating a relative shift of the\nspectral weight to lower frequencies. A recent next-to-leading order\nperturbative calculation of the correlator agrees with the time dependence of\nthe lattice data at the few-percent level. We estimate how much additional\ncontribution from the $\\omega\\lesssim T$ region of the perturbative spectral\nfunction would be required to bring it in agreement with the lattice data at\n$3.1T_c$."
    },
    {
        "anchor": "A new method for Monte Carlo simulation of theories with Grassmann\n  variables: A new algorithm for simulation of theories with dynamical fermions is\npresented. The algorithm is based on obtaining the new configuration U' from\nthe old one U by solving the equation M(U')\\eta= \\omega M(U)\\eta, where M is\nfermionic operator, \\eta is random Gaussian vector, and \\omega is random real\nnumber close to unity. This algorithm can be used for acceleration of current\nsimulations in theories with fermions.",
        "positive": "The glueball spectrum with $N_f=4$ light fermions: We investigate the glueball spectrum for $N_f=4$ fermions corresponding to\nlow pion masses of $m_\\pi \\sim 250$MeV. We do so by making use of\nconfigurations produced with maximally twisted fermions within the framework of\nthe Extended Twisted Mass Collaboration (ETMC). We extract states that belong\nto irreducible representations of the octahedral group of rotations $R$ in\ncombination with the quantum numbers of charge conjugation $C$ and parity $P$,\ni.e. $R^{PC}$. We implement the Generalized Eigenvalue Problem (GEVP) using a\nbasis consisting only of gluonic operators. The purpose of this work is to\ninvestigate the effect of light dynamical quarks on the glueball spectrum and\nhow this compares to the statistically more accurate spectrum of the pure gauge\ntheory. We employed large ensembles of the order of ${\\sim {~\\cal O}}(10 {\\rm\nK})$ configurations for each of three different lattice spacings. Our results\ndemonstrate that in the scalar channel $A_1^{++}$ we obtain an additional,\nlightest state due to the inclusion of light dynamical quarks while the next\ntwo states are consistent with the lightest two states in the pure gauge\ntheory. By contrast the mass of the lightest tensor glueball $J^{PC}=2^{++}$\nappears to be insensitive to the inclusion of sea quarks, as is the mass of the\nlightest pseudoscalar. In addition we perform an investigation of the low lying\nspectrum of the representation $A_1^{++}$ for $N_f=2+1+1$ twisted mass quarks\nwith low masses and demonstrate that the extra lowest state depends strongly on\nthe pion mass. This suggests that the ground state of the scalar glueball has a\nlarge quark content, possibly representing the decay of a glueball to two\npions."
    },
    {
        "anchor": "On the Universality of Matrix Models for Random Surfaces: We present an alternative procedure to eliminate irregular contributions in\nthe perturbation expansion of c=0-matrix models representing the sum over\ntriangulations of random surfaces, thereby reproducing the results of Tutte [1]\nand Brezin et al. [2] for the planar model. The advantage of this method is\nthat the universality of the critical exponents can be proven from general\nfeatures of the model alone without explicit determination of the free energy\nand therefore allows for several straightforward generalizations including\ncases with non-vanishing central charge c< 1.",
        "positive": "Phase transition in fluctuating branched geometry: We study grand--canonical and canonical properties of the model of branched\npolymers proposed in \\cite{adfo}. We show that the model has a fourth order\nphase transition and calculate critical exponents. At the transition the\nexponent $\\gamma$ of the grand-canonical ensemble, analogous to the string\nsusceptibility exponent of surface models, $\\gamma \\sim 0.3237525...$ is the\nfirst known example of positive $\\gamma$ which is not of the form $1/n,\\,\nn=2,3,\\ldots$. We show that a slight modification of the model produces a\ncontinuos spectrum of $\\gamma$'s in the range $(0,1/2]$ and changes the order\nof the transition."
    },
    {
        "anchor": "The $\u039b$-parameter in 3-flavour QCD and $\u03b1_s(m_Z)$ by the\n  ALPHA collaboration: We present results by the ALPHA collaboration for the $\\Lambda$-parameter in\n3-flavour QCD and the strong coupling constant at the electroweak scale,\n$\\alpha_s(m_Z)$, in terms of hadronic quantities computed on the CLS gauge\nconfigurations. The first part of this proceedings contribution contains a\nreview of published material \\cite{Brida:2016flw,DallaBrida:2016kgh} and yields\nthe $\\Lambda$-parameter in units of a low energy scale, $1/L_{\\rm had}$. We\nthen discuss how to determine this scale in physical units from experimental\ndata for the pion and kaon decay constants. We obtain $\\Lambda_{\\overline{\\rm\nMS}}^{(3)} = 332(14)$ MeV which translates to $\\alpha_s(M_Z)=0.1179(10)(2)$\nusing perturbation theory to match between 3-, 4- and 5-flavour QCD.",
        "positive": "Scaling Laws and Effective Dimension in Lattice SU(2) Yang-Mills Theory\n  with a Compactified Extra Dimension: Monte Carlo simulations are performed in a five-dimensional lattice SU(2)\nYang-Mills theory with a compactified extra dimension, and scaling laws are\nstudied. Our simulations indicate that as the compactification radius $R$\ndecreases, the confining phase spreads more and more to the weak coupling\nregime, and the effective dimension of the theory changes gradually from five\nto four. Our simulations also indicate that the limit $a_4 to 0$ with $R/a_4$\nkept fixed exists both in the confining and deconfining phases if $R/a_4$ is\nsmall enough, where $a_4$ is the lattice spacing in the four-dimensional\ndirection. We argue that the color degrees of freedom in QCD are confined only\nfor $R < R_{\\rm max}$, where a rough estimate shows that $1/R_{\\rm max}$ lies\nin the TeV range. Comments on deconstructing extra dimensions are given."
    },
    {
        "anchor": "Scaling investigation of renormalized correlation functions in O(a)\n  improved quenched lattice QCD: We present a scaling investigation of some correlation functions in $\\Or(a)$\nimproved quenched lattice QCD. In particular, as one observable the\nrenormalized PCAC quark mass is considered. Others are constructed such that\nthey become the vector meson mass and the pseudoscalar meson decay constant\nwhen the volume is large. For the present discussion we remain in intermediate\nvolume, $(0.75^3\\times1.5) {fm}^4$ with Schr\\\"odinger functional boundary\nconditions. By fixing the `pion mass' and the spatial lattice size in units of\nthe hadronic scale $r_0$, we simulated four lattices with resolutions ranging\nfrom 0.1 fm to 0.05 fm and performed the extrapolation to the continuum limit.\nThe maximal scaling violation found in the improved theory is a $\\sim$ 6 %\neffect at $a\\simeq 0.1 fm$.",
        "positive": "Testing m(up)=0 on the Lattice: A massless up quark is an intriguing solution to the strong CP problem. We\ndiscuss how lattice computations can be used in conjunction with chiral\nperturbation theory to address the consistency of $m_u=0$ with the observed\nhadron spectrum and interactions. It is not necessary to simulate very light\nquarks-three flavor partially quenched computations with comparable sea and\nvalence quark masses on the order of the strange quark mass could suffice."
    },
    {
        "anchor": "Simulating Yang-Mills theories with a complex coupling: We propose a novel simulation strategy for Yang-Mills theories with a complex\ncoupling, based on the Lefschetz thimble decomposition. We envisage, that the\napproach developed in the present work, can also be adapted to QCD at finite\ndensity, and real time simulations.\n  Simulations with Lefschetz thimbles offer a potential solution to sign\nproblems in Monte Carlo calculations within many different models with complex\nactions. We discuss the structure of Generalized Lefschetz thimbles for pure\nYang-Mills theories with a complex gauge coupling $\\beta$ and show how to\nincorporate the gauge orbits. We propose to simulate such theories on the union\nof the tangential manifolds to the relevant Lefschetz thimbles attached to the\ncritical manifolds of the Yang-Mills action. We demonstrate our algorithm on a\n(1+1)-dimensional U(1) model and discuss how, starting from the main thimble\nresult, successive subleading thimbles can be taken into account via a\nreweighting approach. While we face a residual sign problem, our novel approach\nperforms exponentially better than the standard reweighting approach.",
        "positive": "External Field Dependence of Deconfinement Temperature in SU(3): We study vacuum dynamics of SU(3) lattice gauge theory at finite temperature.\nUsing the lattice Schr\\\"odinger functional, SU(3) vacuum is probed by means of\nan external constant Abelian chromomagnetic field. Our preliminary numerical\ndata suggest that, by increasing the strength of the applied external field,\ndeconfinement temperature decreases towards zero. This means that strong enough\nAbelian chromomagnetic fields destroy confinement of color."
    },
    {
        "anchor": "QCD thermodynamics with Wilson fermions: QCD is investigated at finite temperature using Wilson fermions in the fixed\nscale approach. A 2+1 flavor stout and clover improved action is used at four\nlattice spacings allowing for control over discretization errors. The light\nquark masses in this first study are fixed to heavier than physical values. The\nrenormalized chiral condensate, quark number susceptibility and the Polyakov\nloop is measured and the results are compared with the staggered formulation in\nthe fixed N_t approach. The Wilson results at the finest lattice spacing agree\nwith the staggered results at the highest N_t.",
        "positive": "Eigenvalue spectra of QCD and the fate of $U_A(1)$ breaking towards the\n  chiral limit: The finite temperature phase diagram of QCD with two massless quark flavors\nis not yet understood because of the subtle effects of anomalous $U_A(1)$\nsymmetry. In this work we address this issue by studying the fate of the\nanomalous $U_A(1)$ symmetry in $2+1$ flavor QCD just above the chiral crossover\ntransition temperature $T_c$, lowering the light quark mass towards the chiral\nlimit along line of constant physical strange quark mass. We use the gauge\nconfigurations generated using the Highly Improved Staggered Quark (HISQ)\ndiscretization on lattice volumes $32^3\\times8$ and $56^3\\times 8$ to study the\nrenormalized eigenvalue spectrum of QCD with valence overlap Dirac operator. We\nhave implemented new numerical techniques that have allowed us to measure about\n$100$-$200$ eigenvalues of the gauge ensembles with light quark masses $\\gtrsim\n0.6$ MeV. From a detailed analysis of the dependence of the renormalized\neigenvalue spectrum and $U_A(1)$ breaking observables on the light quark mass,\nour study suggests $U_A(1)$ is broken at $T\\gtrsim T_c$ even when the chiral\nlimit is approached."
    },
    {
        "anchor": "Update on flavor diagonal nucleon charges from clover fermions: We present a summary of the full calculation of the axial, scalar and tensor\nflavor diagonal charges of the nucleon carried out using Wilson-clover fermions\non eight ensembles generated using 2+1+1-flavors of highly improved staggered\nquarks (HISQ) by the MILC collaboration. We also give results for the $3\\times\n3$ matrix of renormalization factors between the RI-sMOM and $\\overline{\\rm\nMS}$ scheme for the 2+1 flavor theory that include flavor mixing. Preliminary\nresults for $g_{A,S,T}^{u,d,s}$ are presented in the $\\overline{\\rm MS}$ scheme\nat scale 2 GeV.",
        "positive": "Investigation of Lattice QCD with Wilson fermions with Gaussian Smearing: We present a detailed study of pion and rho mass, decay constants and quark\nmass in Lattice QCD with two flavors of dynamical quarks. We use Wilson gauge\nand fermion action at $\\beta=5.6$ on $ 16^3 \\times 32 $ lattice at eight values\nof the Wilson hopping parameter in the range 0.156 - 0.158. We perform a\ndetailed investigation of the effect of gaussian smearing on both source and\nsink. We determine the optimum smearing parameter for various correlators for\neach value of the Wilson hopping parameter. The effects of smearing on\nobservables are compared with those measured using local operators. We also\ninvestigate systematic effects in the extraction of masses and decay constants\nusing different types of correlation functions for pion observables. We make\ninteresting observations regarding chiral extrapolations and finite volume\neffects of different operators."
    },
    {
        "anchor": "Casimir effect for fermions on the lattice: The conventional Casimir effect has been studied in the continuous spacetime,\nbut to elucidate its counterpart in the lattice space is an important subject.\nHere, we discuss various types of Casimir effects for quantum fields on the\nlattice. By using a definition of the Casimir energy on the lattice, we show\nthat the Casimir effect for the Wilson fermion is similar to that for the\ncontinuous Dirac fermion. We apply our definition to an effective Hamiltonian\ndescribing Dirac semimetals, such as Cd$_{3}$As$_{2}$ and Na$_{3}$Bi, and find\nan oscillatory behavior of the Casimir energy as a function of film thickness\nof semimetals. We also study contributions from Landau levels under magnetic\nfields and the Casimir effect for nonrelativistic particle fields on the\nlattice.",
        "positive": "QCD equation of state at non-zero chemical potential: We present our new results for the QCD equation of state at nonzero chemical\npotential at N_t=6 and compare them with N_t=4. We use the Taylor expansion\nmethod with terms up to sixth order in simulations with 2+1 flavors of improved\nasqtad quarks along a line of constant physics with m_l=0.1 m_s and\napproximately physical strange quark mass m_s."
    },
    {
        "anchor": "Vacuum Tunneling and Periodic Structure in Lattice Higgs Models: Using a geometric definition for the lattice Chern-Simons term in even\ndimensions, we have studied the distribution of Chern-Simons numbers for the\n2d-U(1) and the 4d-SU(2) lattice Higgs models. The periodic structure of the\ndistributions is preserved in our lattice formulation and has been examined in\ndetail. In both cases the finite size effects visible in the distribution of\nChern-Simons numbers are well accounted for by the Haar measure. Moreover, we\nfind that $\\langle N_{CS}^2 \\rangle$ grows with the spatial volume. We also\nfind numerical evidence that tunneling in 4d is increased at high temperature.\n(PS-File including Figures available via E-mail: plache@physv.uni-bielefeld.de)",
        "positive": "Lattice QCD Evidence that the Lambda(1405) Resonance is an\n  Antikaon-Nucleon Molecule: For almost 50 years the structure of the Lambda(1405) resonance has been a\nmystery. Even though it contains a heavy strange quark and has odd parity, its\nmass is lower than any other excited spin-1/2 baryon. Dalitz and co-workers\nspeculated that it might be a molecular state of an antikaon bound to a\nnucleon. However, a standard quark-model structure is also admissible. Although\nthe intervening years have seen considerable effort, there has been no\nconvincing resolution. Here we present a new lattice QCD simulation showing\nthat the strange magnetic form factor of the Lambda(1405) vanishes, signaling\nthe formation of an antikaon-nucleon molecule. Together with a Hamiltonian\neffective-field-theory model analysis of the lattice QCD energy levels, this\nstrongly suggests that the structure is dominated by a bound antikaon-nucleon\ncomponent. This result clarifies that not all states occurring in nature can be\ndescribed within a simple quark model framework and points to the existence of\nexotic molecular meson-nucleon bound states."
    },
    {
        "anchor": "A gauge invariant cluster algorithm for the Ising spin glass: The frustrated Ising model in two dimensions is revisited. The frustration is\nquantified in terms of the number of non-trivial plaquettes which is invariant\nunder the Nishimori gauge symmetry. The exact ground state energy is calculated\nusing Edmond's algorithm. A novel cluster algorithm is designed which treats\ngauge equivalent spin glasses on equal footing and allows for efficient\nsimulations near criticality. As a first application, the specific heat near\ncriticality is investigated.",
        "positive": "Momentum dependence of kaon semileptonic form factors with Nf=2+1+1\n  Twisted Mass fermions: We present a lattice QCD determination of the vector and scalar form factors\nof the kaon semileptonic decay $K \\to \\pi \\ell \\nu$, which is relevant for the\ndetermination of the CKM matrix element $|V_{us}|$ from experimental data. Our\nresults are based on the gauge configurations produced by the European Twisted\nMass Collaboration with Nf = 2+1+1 dynamical fermions. We simulated at three\ndifferent values of the lattice spacing and with pion masses as small as 210\nMeV. Our estimate for the vector form factor at zero 4-momentum transfer is\n$f_+(0) = 0.9709 (46)$, where the uncertainty is both statistical and\nsystematic. By combining our result with the latest experimental value of\n$f_+(0)|V_{us}|$ we obtain $|V_{us}| = 0.2230 (11)$, which satisfies the\nunitarity constraint of the Standard Model at the permille level using the\nupdated determination of $|V_{ud}|$ coming from superallowed nuclear $\\beta$\ndecays. We present also the momentum dependence of the vector and scalar form\nfactors in the whole range of values of the squared 4-momentum transfer\nmeasured in $K_{\\ell 3}$ decays, obtaining a good agreement with the\nexperimental data."
    },
    {
        "anchor": "Domain-wall fermions with U(1) dynamical gauge fields in\n  (4+1)-dimensions: We carry out a numerical simulation of a domain-wall model in (4+1)\ndimensions, in the presence of a quenched U(1) dynamical gauge field only in an\nextra dimension, corresponding to the weak coupling limit of a (4-dimensional)\nphysical gauge coupling. Our numerical data suggest that the zero mode seems\nabsent in the symmetric phase, so that it is difficult to construct a lattice\nchiral gauge theory in the continuum limit.",
        "positive": "Three particles on the lattice: I give a review of existing frameworks, which are designed to analyse lattice\ndata in the three-particle sector. A particular emphasis is laid on the\nfoundations of the theory, where the separation of the short- and long-range\neffects plays a central role. It is shown that the use of the effective field\ntheory approach enables one to carry out this separation in a natural and\nefficient way. In conclusion, a few examples of the analysis of lattice data\nare considered for illustration."
    },
    {
        "anchor": "Lattice study of thermodynamic properties of dense QC$_2$D: In this paper we study thermodynamic properties of dense cold $SU(2)$ QCD\nwithin lattice simulation with dynamical rooted staggered quarks which in the\ncontinuum limit correspond to $N_f=2$ quark flavours. We calculate baryon\ndensity, renormalized chiral and diquark condensates for various baryon\nchemical potentials in the region $\\mu \\in (0,\\,2000)$ MeV. It is found, that\nin the region $\\mu \\in (0,\\,540)$ MeV the system is well described by the ChPT\npredictions. In the region $\\mu > 540$ MeV the system becomes sufficiently\ndense and ChPT is no longer applicable to describe lattice data. For chemical\npotentials $\\mu > 900$ MeV we observe formation of the Fermi sphere, and the\nsystem is similar to the one described by the Bardeen-Cooper-Schrieffer theory\nwhere the the diquarks play a role of Cooper pairs. In order to study how\nnonzero baryon density influences the gluon background we calculate\nchromoelectric and chromomagnetic fields, as well as the topological\nsusceptibility. We find that the chromoelectric field and the topological\nsusceptibility decrease, whereas the chromomagnetic field increases with rising\nof baryon chemical potential. Finally we study the equation of state of dense\ntwo-color quark matter.",
        "positive": "The chiral and angular momentum content of the $\u03c1$-mesons in lattice\n  QCD: The variational method allows one to study the mixing of interpolators with\ndifferent chiral transformation properties in the nonperturbatively determined\nphysical state. It is then possible to define and calculate in a\ngauge-invariant manner the chiral as well as the partial wave content of the\nquark-antiquark component of a meson in the infrared, where mass is generated.\nUsing a unitary transformation from the chiral basis to the $^{2S+1}L_J$ basis\none may extract the partial wave content of a meson. We present results for the\n$\\rho$- and $\\rho'$-mesons using a simulation with $N_f=2$ dynamical quarks,\nall for lattice spacings close to 0.15 fm. Our results indicate a strong chiral\nsymmetry breaking in the $\\rho$ state and its simple $^3S_1$-wave composition\nin the infrared. For the $\\rho'$-meson we find a small chiral symmetry breaking\nin the infrared as well as a leading contribution of the $^3D_1$ partial wave,\nwhich is contradictory to the quark model."
    },
    {
        "anchor": "Lattice QCD with two light Wilson quarks and maximally twisted mass: We summarise status and recent results of the European Twisted Mass\ncollaboration (ETMC). The collaboration has generated gauge configurations for\nthree different values of the lattice spacing smaller or equal 0.1 fm and\nvalues of the charged pseudo scalar mass as low as 300 MeV with two flavours of\nmaximally twisted mass quarks. We provide evidence that O(a) improvement works\nvery well with maximally twisted mass fermions and that also higher order\nlattice artifacts appear to be small. The currently only quantity in the light\nmeson and baryon sector where cut-off effects are visible is the neutral pseudo\nscalar meson mass and we present an attempt to understand this from a\ntheoretical point of view.\n  We describe finite size effects and quark mass dependence of the mass and\ndecay constant of the (charged) pseudo scalar meson with chiral perturbation\ntheory formulae and our current estimate for the low energy constants l_{3,4}\nis l_3=3.44(8)(35) and l_4=4.61(4)(11). Results for the average up-down, the\nstrange and the charm quark mass and the chiral condensate are also presented.",
        "positive": "Exact Supersymmetry on the Lattice: We discuss the possibility of representing supersymmetry exactly in a lattice\ndiscretized system. In particular, we construct a perfect supersymmetric action\nfor the Wess-Zumino model."
    },
    {
        "anchor": "Extension to order $\u03b2^{23}$ of the high-temperature expansions for\n  the spin-1/2 Ising model on the simple-cubic and the body-centered-cubic\n  lattices: Using a renormalized linked-cluster-expansion method, we have extended to\norder $\\beta^{23}$ the high-temperature series for the susceptibility $\\chi$\nand the second-moment correlation length $\\xi$ of the spin-1/2 Ising models on\nthe sc and the bcc lattices. A study of these expansions yields updated direct\nestimates of universal parameters, such as exponents and amplitude ratios,\nwhich characterize the critical behavior of $\\chi$ and $\\xi$. Our best\nestimates for the inverse critical temperatures are\n  $\\beta^{sc}_c=0.221654(1)$ and $\\beta^{bcc}_c=0.1573725(6)$. For the\nsusceptibility exponent we get $\\gamma=1.2375(6)$ and for the correlation\nlength exponent we get $\\nu=0.6302(4)$.\n  The ratio of the critical amplitudes of $\\chi$ above and below the critical\ntemperature is estimated to be $C_+/C_-=4.762(8)$. The analogous ratio for\n$\\xi$ is estimated to be $f_+/f_-=1.963(8)$. For the correction-to-scaling\namplitude ratio we obtain $a^+_{\\xi}/a^+_{\\chi}=0.87(6)$.",
        "positive": "String breaking in SU(2) gauge theory with scalar matter fields: We investigate the static potential in the confinement phase of the SU(2)\nHiggs model on the lattice, where this model is expected to have properties\nsimilar to QCD. We observe that Wilson loops are inadequate to determine the\npotential at large distances, where the formation of two color-neutral mesons\nis expected. Introducing smeared fields and a suitable matrix correlation\nfunction, we are able to overcome this difficulty. We observe string breaking\nat a distance $r_b \\approx 1.8 r_0$, where the length scale $r_0$ has a value\n$r_0 \\approx 0.5 fm$ in QCD. The method presented here may lead the way towards\na treatment of string breaking in QCD."
    },
    {
        "anchor": "One-loop calculations in Supersymmetric Lattice QCD: We study the self energies of all particles which appear in a lattice\nregularization of supersymmetric QCD (${\\cal N}=1$). We compute, perturbatively\nto one-loop, the relevant two-point Green's functions using both the\ndimensional and the lattice regularizations. Our lattice formulation employs\nthe Wilson fermion acrion for the gluino and quark fields. The gauge group that\nwe consider is $SU(N_c)$ while the number of colors, $N_c$ and the number of\nflavors, $N_f$, are kept as generic parameters. We have also searched for\nrelations among the propagators which are computed from our one-loop results.\nWe have obtained analytic expressions for the renormalization functions of the\nquark field ($Z_\\psi$), gluon field ($Z_u$), gluino field ($Z_\\lambda$) and\nsquark field ($Z_{A_\\pm}$).\n  We present here results from dimensional regularization, relegating to a\nforthcoming publication our results along with a more complete list of\nreferences. Part of the lattice study regards also the renormalization of quark\nbilinear operators which, unlike the non-supersymmetric case, exhibit a rich\npattern of operator mixing at the quantum level.",
        "positive": "Lattice QCD and Axion Cosmology: The Strong CP Problem can be resolved by introducing an additional global\nsymmetry known as Peccei-Quinn symmetry. Once PQ symmetry is broken the\nassociated particle, the QCD axion, is a plausible dark matter candidate.\nCalculating the cosmological energy density of the axion requires\nnonperturbative QCD input---the high-temperature topological susceptibility. I\nwill show results from a pure-glue calculation and examine the implications for\nthe axion mass and coupling."
    },
    {
        "anchor": "The spectrum of static-light baryons in twisted mass lattice QCD: We compute the static-light baryon spectrum with N_f = 2 flavors of sea\nquarks using Wilson twisted mass lattice QCD. As light valence quarks we\nconsider quarks, which have the same mass as the sea quarks with corresponding\npion masses in the range 340 MeV < m_PS < 525 MeV, as well as partially\nquenched quarks, which have the mass of the physical s quark. We extract masses\nof states with isospin I = 0, 1/2, 1, with strangeness S = 0, -1, -2, with\nangular momentum of the light degrees of freedom j = 0, 1 and with parity P =\n+, -. We present a preliminary extrapolation in the light u/d and an\ninterpolation in the heavy b quark mass to the physical point and compare with\navailable experimental results.",
        "positive": "Lyapunov Exponent of SU(3) Gauge Theory: The classical SU(3) gauge theory is shown to be deterministic chaotic. Its\nlargest Lyapunov exponent is dertermined, from which a short time scale of\nthermalization of a pure gluon system is estimated. The connection to gluon\ndamping rate is discussed."
    },
    {
        "anchor": "Infinite Volume and Continuum Limits of the Landau-Gauge Gluon\n  Propagator: We extend a previous improved action study of the Landau gauge gluon\npropagator, by using a variety of lattices with spacings from $a = 0.17$ to\n0.41 fm, to more fully explore finite volume and discretization effects. We\nalso extend a previously used technique for minimizing lattice artifacts, the\nappropriate choice of momentum variable or ``kinematic correction'', by\nconsidering it more generally as a ``tree-level correction''. We demonstrate\nthat by using tree-level correction, determined by the tree-level behavior of\nthe action being considered, it is possible to obtain scaling behavior over a\nvery wide range of momenta and lattice spacings. This makes it possible to\nexplore the infinite volume and continuum limits of the Landau-gauge gluon\npropagator.",
        "positive": "2+1 Flavor QCD simulated in the epsilon-regime in different topological\n  sectors: We generated configurations with the parametrized fixed-point Dirac operator\nD_{FP} on a (1.6 fm)^4 box at a lattice spacing a=0.13 fm. We compare the\ndistributions of the three lowest k=1,2,3 eigenvalues in the nu= 0,1,2\ntopological sectors with that of the Random Matrix Theory predictions. The\nratios of expectation values of the lowest eigenvalues and the cumulative\neigenvalue distributions are studied for all combinations of k and nu. After\nincluding the finite size correction from one-loop chiral perturbation theory\nwe obtained for the chiral condensate in the MSbar scheme\nSigma(2GeV)^{1/3}=0.239(11) GeV, where the error is statistical only."
    },
    {
        "anchor": "The Stefan-Boltzmann law: SU(2) versus SO(3) lattice gauge theory: We investigate the high temperature limit of SU(2) and SO(3) lattice gauge\ntheory, respectively. In particular, we study the Stefan-Boltzmann constant in\nboth cases. As is well known, the Stefan-Boltzmann constant extracted from\nSU(2) lattice gauge theory by incorporating finite size effects is smaller than\nthe continuum value which assumes three gluon degrees of freedom. On the other\nhand, the extrapolation of our SO(3) lattice data comes much closer to the\ncontinuum value. This rises the question whether SU(2) and SO(3) lattice gauge\ntheories represent different quantum theories in the continuum limit.",
        "positive": "Comparison of SO(3) and SU(2) lattice gauge theory: The Villain form of SO(3) lattice gauge theory is studied and compared to\nWilson's SU(2) theory. The topological invariants in SO(3) which correspond to\ntwisted boundary conditions in SU(2) are discussed and lattice observables are\nintroduced for them. An apparent SO(3) phase with negative adjoint Polyakov\nloop is explained in terms of these observables. The electric twist free\nenergy, an order parameter for the confinement-deconfinement transition, is\nmeasured in both theories to calibrate the temperature. The results indicate\nthat lattices with about 700^4 sites or larger will be needed to study the\nSO(3) confined phase. Alternative actions are discussed and an analytic path\nconnecting SO(3) and SU(2) lattice gauge theory at weak coupling is exhibited.\nThe relevance for confinement of the centre of the gauge group is discussed."
    },
    {
        "anchor": "Fermion masses through four-fermion condensates: Fermion masses can be generated through four-fermion condensates when\nsymmetries prevent fermion bilinear condensates from forming. This less\nexplored mechanism of fermion mass generation is responsible for making four\nreduced staggered lattice fermions massive at strong couplings in a lattice\nmodel with a local four-fermion coupling. The model has a massless fermion\nphase at weak couplings and a massive fermion phase at strong couplings. In\nparticular there is no spontaneous symmetry breaking of any lattice symmetries\nin both these phases. Recently it was discovered that in three space-time\ndimensions there is a direct second order phase transition between the two\nphases. Here we study the same model in four space-time dimensions and find\nresults consistent with the existence of a narrow intermediate phase with\nfermion bilinear condensates, that separates the two asymptotic phases by\ncontinuous phase transitions.",
        "positive": "Random Matrix Theory and the Spectra of Overlap Fermions: The application of Random Matrix Theory to the Dirac operator of QCD yields\npredictions for the probability distributions of the lowest eigenvalues. We\nmeasured Dirac operator spectra using massless overlap fermions in quenched QCD\nat topological charge \\nu = 0, +- 1 and +- 2, and found agreement with those\npredictions - at least for the first non-zero eigenvalue - if the volume\nexceeds about (1.2 fm)^4."
    },
    {
        "anchor": "Non-perturbative renormalization in QCD+QED and its application to weak\n  decays: We present a novel strategy to renormalize lattice operators in QCD+QED,\nincluding first order QED corrections to the non-perturbative evaluation of QCD\nrenormalization constants. Our procedure takes systematically into account the\nmixed non-factorizable QCD+QED effects which were neglected in previous\ncalculations, thus significantly reducing the systematic uncertainty on\nrenormalization corrections. The procedure is presented here in the RI'-MOM\nscheme, but it can be applied to other schemes (e.g. RI-SMOM) with appropriate\nchanges. We discuss the application of this strategy to the calculation of the\nleading isospin breaking corrections to the leptonic decay rates\n$\\Gamma(\\pi_{\\mu 2})$ and $\\Gamma(K_{\\mu 2})$, evaluated for the first time on\nthe lattice. The precision in the matching to the $W$-regularization scheme is\nimproved to $\\mathcal{O}(\\alpha_{em}\\alpha_s(M_W))$ with respect to previous\ncalculations. Finally, we show the updated precise result obtained for the\nCabibbo-Kobayashi-Maskawa matrix element $|V_{us}|$.",
        "positive": "The Lattice QCD Study of the Three-Nucleon Force: We investigate three-nucleon forces (3NF) from lattice QCD simulations,\nutilizing the Nambu-Bethe-Salpeter (NBS) wave function to determine two-nucleon\nforces (2NF) and 3NF on the same footing. Quantum numbers of the three-nucleon\n(3N) system are chosen to be (I, J^P)=(1/2, 1/2^+) (the triton channel). We\nconsider the simplest geometrical configuration where 3N are aligned linearly\nwith an equal spacing, to reduce the enormous computational cost. Lattice QCD\nsimulations are performed using Nf=2 dynamical clover fermion configurations at\nthe lattice spacing of a = 0.156 fm on a 16^3 x 32 lattice with a large quark\nmass corresponding to m(\\pi) = 1.13 GeV. We find repulsive 3NF at short\ndistance."
    },
    {
        "anchor": "A Comparison of Clover and Wilson Spectroscopy in the Presence of\n  Dynamical Quarks: We present preliminary results of light hadron spectroscopy using valence,\ntadpole-improved, Clover fermions on an ensemble of gauge configurations\ngenerated with 2 flavors of staggered fermions at a beta of 5.6. We compare the\nslope and intercept of the curve M_V vs. M_PS^2 for Clover and Wilson fermions.\nWe show that a higher order chiral perturbation theory ansatz works very well\nfor chiral extrapolations.",
        "positive": "Light-cone distribution amplitudes of pseudoscalar mesons from lattice\n  QCD: We present the first lattice determination of the two lowest Gegenbauer\nmoments of the leading-twist pion and kaon light-cone distribution amplitudes\nwith full control of all errors. The calculation is carried out on 35 different\nCLS ensembles with $N_f=2+1$ flavors of dynamical Wilson-clover fermions. These\ncover a multitude of pion and kaon mass combinations (including the physical\npoint) and 5 different lattice spacings down to $a=0.039\\,$fm. The momentum\nsmearing technique and a new operator basis are employed to reduce statistical\nfluctuations and to improve the overlap with the ground states. The results are\nobtained from a combined chiral and continuum limit extrapolation that includes\nthree separate trajectories in the quark mass plane.\n  The present arXiv version (v3) includes an Addendum where we update the\nresults using the recently calculated three-loop matching factors for the\nconversion from the RI'/SMOM to the $\\overline{\\text{MS}}$ scheme. We find\n$a_2^\\pi=0.116^{+19}_{-20}$ for the pion, $a_1^K=0.0525^{+31}_{-33}$ and\n$a_2^K=0.106^{+15}_{-16}$ for the kaon. We also include the previous values,\nwhich were obtained with two-loop matching."
    },
    {
        "anchor": "Janossy densities for chiral random matrix ensembles and their\n  applications to two-color QCD: We compute individual distributions of low-lying eigenvalues of massive\nchiral random matrix ensembles by the Nystr\\\"om-type quadrature method for\nevaluating the Fredholm determinant and Pfaffian that represent the analytic\ncontinuation of the Janossy densities (conditional gap probabilities). A\ncompact formula for individual eigenvalue distributions suited for precise\nnumerical evaluation by the Nystr\\\"om-type method is obtained in an explicit\nform, and the $k^{\\rm{\\small th}}$ smallest eigenvalue distributions are\nnumerically evaluated for chiral unitary and symplectic ensembles in the\nmicroscopic limit. As an application of our result, the low-lying Dirac spectra\nof the SU(2) lattice gauge theory with $N_F=8$ staggered flavors are fitted to\nthe numerical prediction from the chiral symplectic ensemble, leading to a\nprecise determination of the chiral condensateof a two-color QCD-like system in\nthe future.",
        "positive": "Two flavor QCD and confinement - II: This paper is part of a program of investigation of the chiral transition in\nNf=2 QCD, started in Phys.Rev.D72:114510,2005. Progress is reported on the\nunderstanding of some possible systematic errors. A direct test of first order\nscaling is presented."
    },
    {
        "anchor": "Strange Quark Contribution to the Nucleon - (Dissertation): The strangeness contribution to the electric and magnetic properties of the\nnucleon has been under investigation experimentally for many years. Lattice\nQuantum Chromodynamics (LQCD) gives theoretical predictions of these\nmeasurements by implementing the continuum gauge theory on a discrete,\nmathematical Euclidean space-time lattice which provides a cutoff removing the\nultra-violet divergences. In this dissertation we will discuss effective\nmethods using LQCD that will lead to a better determination of the strangeness\ncontribution to the nucleon properties. Strangeness calculations are demanding\ntechnically and computationally. Sophisticated techniques are required to carry\nthem to completion. In this thesis, new theoretical and computational methods\nfor this calculation such as twisted mass fermions, perturbative subtraction,\nand General Minimal Residual (GMRES) techniques which have proven useful in the\ndetermination of these form factors will be investigated. Numerical results of\nthe scalar form factor using these techniques are presented. These results give\nvalidation to these methods in future calculations of the strange quark\ncontribution to the electric and magnetic form factors.",
        "positive": "Some remarks on cyclization and periodicity: Conditions when application of cyclization procedure does not lead to the\nperiodic function are specified. Sufficient conditions under which obtained\nfunction is periodic are stated."
    },
    {
        "anchor": "Lattice Formulation of the N=4 D=3 Twisted Super Yang-Mills: A lattice formulation of a three dimensional super Yang-Mills model with a\ntwisted N=4 supersymmetry is proposed. The extended supersymmetry algebra of\nall eight supercharges is fully and exactly realized on the lattice with a\nmodified \"Leibniz rule\". The formulation we employ here is a three dimensional\nextension of the manifestly gauge covariant method which was developed in our\nprevious proposal of Dirac-K\\\"ahler twisted N=2 super Yang-Mills on a two\ndimensional lattice. The twisted N=4 supersymmetry algebra is geometrically\nrealized on a three dimensional lattice with link supercharges and the use of\n\"shifted\" (anti-)commutators. A possible solution to the recent critiques on\nthe link formulation will be discussed.",
        "positive": "High Energy Physics from High Performance Computing: We discuss Quantum Chromodynamics calculations using the lattice regulator.\nThe theory of the strong force is a cornerstone of the Standard Model of\nparticle physics. We present USQCD collaboration results obtained on Argonne\nNational Lab's Intrepid supercomputer that deepen our understanding of these\nfundamental theories of Nature and provide critical support to frontier\nparticle physics experiments and phenomenology."
    },
    {
        "anchor": "Warped Domain Wall Fermions: We consider Kaplan's domain wall fermions in the presence of an Anti-de\nSitter (AdS) background in the extra dimension. Just as in the flat space case,\nin a completely vector-like gauge theory defined after discretizing this extra\ndimension, the spectrum contains a very light charged fermion whose chiral\ncomponents are localized at the ends of the extra dimensional interval. The\ncomponent on the IR boundary of the AdS space can be given a large mass by\ncoupling it to a neutral fermion via the Higgs mechanism. In this theory, gauge\ninvariance can be restored either by taking the limit of infinite proper length\nof the extra dimension or by reducing the AdS curvature radius towards zero. In\nthe latter case, the Kaluza-Klein modes stay heavy and the resulting classical\ntheory approaches a chiral gauge theory, as we verify numerically. Potential\ndifficulties for this approach could arise from the coupling of the\nlongitudinal mode of the light gauge boson, which has to be treated\nnon-perturbatively.",
        "positive": "Lattice QCD and High Baryon Density State: We report our recent studies on the finite density QCD obtained from lattice\nQCD simulation with clover-improved Wilson fermions of two flavor and\nRG-improved gauge action. We approach the subject from two paths, i.e., the\nimaginary and real chemical potentials."
    },
    {
        "anchor": "Heating and small-size instantons in the $O(3) \\:\u03c3$ model on the\n  lattice: We study the role of small-size instantons in the determination of the\ntopological susceptibility of the 2-d $O(3) \\: \\sigma $ model on the lattice.\nIn particular, we analyze how they affect the non-perturbative determination,\nby Monte Carlo techniques, of the renormalizations on the lattice. As a result,\nwe obtain a high-precision non-perturbative determination of the mixing with\nthe unity operator, finding good agreement with perturbative computations. We\nalso obtain the size distribution of instantons in the physical vacuum up to\nvery small values of the size in physical units, without observing any\nultraviolet cut-off. Moreover, we show by analytical calculation that the\nmixing of the topological susceptibility with the action density is a\nnegligible part of the whole non-perturbative signal.",
        "positive": "The continuum limit of quark number susceptibilities: We report the continuum limit of quark number susceptibilities in quenched\nQCD. Deviations from ideal gas behaviour at temperature T increase as the\nlattice spacing is decreased from T/4 to T/6, but a further decrease seems to\nhave very little effect. The measured susceptibilities are 20% lower than the\nideal gas values, and also 10% below the hard thermal loop (HTL) results. The\noff-diagonal susceptibility is several orders of magnitude smaller than the HTL\nresults. We verify a strong correlation between the lowest screening mass and\nthe susceptibility. We also show that the quark number susceptibilities give a\nreasonable account of the Wroblewski parameter, which measures the strangeness\nyield in a heavy-ion collision."
    },
    {
        "anchor": "Action and topological density carried by Abelian monopoles in finite\n  temperature pure SU(2) gauge theory: an analysis using RG smoothing: We test a new parametrization of a suitably truncated classically perfect\naction for SU(2) pure gauge theory with respect to self-consistency and locate\nthe deconfinement transition on a 12^3X4 lattice. Using the technique of\nsmoothing (blocking followed by inverse blocking) we demonstrate clustering of\naction and topological charge density. Concentrating on the Abelian monopoles\nfound in smoothed configurations after Abelian projection from the maximally\nAbelian gauge, we present evidence for their role as carriers of non-Abelian\naction and topological charge.",
        "positive": "Onium Masses with Three Flavors of Dynamical Quarks: We have greatly extended an earlier calculation of the charmonium spectrum on\nthree flavor dynamical quark ensembles by using more recent ensembles generated\nby the MILC collaboration. The heavy quarks are treated using the Fermilab\nformulation. The charmonium state masses are in reasonable agreement with the\nobserved spectrum; however, some of the spin splittings may still be too small."
    },
    {
        "anchor": "Lattice instanton action from 3D SU(2) Georgi-Glashow model: 3D Georgi-Glashow model is studied on the lattice in the London limit in an\ninfrared but an intermediate region before the screening appears. Abelian and\ninstanton dominances are observed after abelian projections in a unitary gauge\nand roughly in the maximally abelian gauge. Using an inverse Monte-Carlo\nmethod, we determine an effective instanton action in both gauges. When we\nrestrict ourselves to some regions of parameters $\\beta$ and $\\kappa$, we\nobtain an almost perfect instanton action, performing a block-spin\ntransformation on the dual lattice. It takes a form of a Coulomb gas and\nreproduces fairly well the string tension obtained analytically by Polyakov.\nThe almost perfect actions in both gauges look the same in the infrared region,\nwhich suggests gauge independence.",
        "positive": "Center clusters and their percolation properties in lattice QCD: Properties of local Polyakov loops are studied in finite temperature lattice\nQCD and SU(3) lattice gauge theory. We evaluate local Polyakov loops, identify\nthe closest center element for each loop and investigate cluster properties of\nthese center phases. For a suitable definition of the clusters we find that the\ndeconfinement transition of pure SU(3) gauge theory may be characterized by\npercolation of the center clusters. For the case of full QCD cluster\nobservables show a behavior which seems to be compatible with a smooth\ncrossover type of transition."
    },
    {
        "anchor": "Three-dimensional finite temperature Z$_2$ gauge theory with tensor\n  network scheme: We apply a tensor network scheme to finite temperature Z$_2$ gauge theory in\n2+1 dimensions. Finite size scaling analysis with the spatial extension up to\n$N_{\\sigma}=4096$ at the temporal extension of $N_\\tau=2,3,5$ allows us to\ndetermine the transition temperature and the critical exponent $\\nu$ at high\nlevel of precision, which shows the consistency with the Svetitsky-Yaffe\nconjecture.",
        "positive": "Variational Approach to the Calculation of gA: We present a lattice QCD calculation of the nucleon axial charge, gA, using a\nvariational approach. After a brief outline of how the variational method is\napplied to the calculation of form factors, we present results for gA using\nthis method. We find that ground state dominance is rapid, evident in the early\nonset of a clear plateau in the correlation function ratio proportional to gA.\nThrough a comparison with results obtained via traditional methods, we show how\nexcited state effects can suppress gA by as much as 8% if sources are not\nproperly tuned."
    },
    {
        "anchor": "A Monte Carlo study of Inverse Symmetry Breaking: We make a Monte Carlo study of the coupled two-scalar\n$\\lambda\\phi^2_1\\phi^2_2$ model in four dimensions at finite temperature. We\nfind no trace of Inverse Symmetry Breaking for values of the renormalized\nparameters for which perturbation theory predicts this phenomenon.",
        "positive": "Monopole action and condensation in SU(2) QCD: An effective monopole action for various extended monopoles is derived from\nvacuum configurations after abelian projection in the maximally abelian gauge\nin $SU(2)$ QCD. The action appears to be independent of the lattice volume.\nMoreover it seems to depend only on the physical lattice spacing of the\nrenormalized lattice, not on $\\beta$. Entropy dominance over energy of monopole\nloops is seen on the renormalized lattice with the spacing $b>b_c\\simeq\n5.2\\times10^{-3} \\Lambda_L^{-1}$. This suggests that monopole condensation\nalways (for all $\\beta$) occurs in the infinite-volume limit of lattice QCD."
    },
    {
        "anchor": "Cosmological Phase transitions from Lattice Field Theory: In this proceedings contribution we discuss the fate of the electroweak and\nthe quantum chromodynamics phase transitions relevant for the early stage of\nthe universe at non-zero temperature. These phase transitions are related to\nthe Higgs mechanism and the breaking of chiral symmetry, respectively. We will\nreview that non-perturbative lattice field theory simulations show that these\nphase transitions actually do not occur in nature and that physical observables\nshow a completely smooth behaviour as a function of the temperature.",
        "positive": "Complex RG flows for 2D nonlinear O(N) sigma models: Motivated by recent attempts to find nontrivial infrared fixed points in\n4-dimensional lattice gauge theories, we discuss the extension of the\nrenormalization group (RG) transformations to complex coupling spaces for O(N)\nmodels on LxL lattices, in the large-N limit. We explain the Riemann sheet\nstructure and singular points of the finite L mappings between the mass gap and\nthe 't Hooft coupling. We argue that the Fisher's zeros appear on \"strings\"\nending approximately near these singular points. We show that for the spherical\nmodel at finite N and L, the density of states is stripwise polynomial in the\ncomplex energy plane. We compare finite volume complex flows obtained from the\nrescaling of the ultraviolet cutoff in the gap equation and from the\ntwo-lattice matching. In both cases, the flows are channelled through the\nsingular points and end at the strong coupling fixed points, however strong\nscheme dependence appear when the Compton wavelength of the mass gap is larger\nthan the linear size of the system. We argue that the Fisher's zeros control\nthe global properties of the complex flows. We briefly discuss the implications\nfor perturbation theory, proofs of confinement and searches for nontrivial\ninfrared fixed points in models beyond the standard model."
    },
    {
        "anchor": "Axial anomaly with the overlap-Dirac operator in arbitrary dimensions: We evaluate for arbitrary even dimensions the classical continuum limit of\nthe lattice axial anomaly defined by the overlap-Dirac operator. Our\ncalculational scheme is simple and systematic. In particular, a powerful\ntopological argument is utilized to determine the value of a lattice integral\ninvolved in the calculation. When the Dirac operator is free of species\ndoubling, the classical continuum limit of the axial anomaly in various\ndimensions is combined into a form of the Chern character, as expected.",
        "positive": "Sums of permanental minors using Grassmann algebra: We show that a formalism proposed by Creutz to evaluate Grassmann integrals\nprovides an algorithm of complexity $O(2^n n^3)$ to compute the generating\nfunction for the sum of the permanental minors of a matrix of order $n$. This\nalgorithm improves over the Brualdi-Ryser formula, whose complexity is at least\n$O(2^{\\frac{5n}{2}})$. In the case of a banded matrix with band width $w$ and\nrank $n$ the complexity is $O(2^{min(2w, n)} (w + 1) n^2)$. Related algorithms\nfor the matching and independence polynomials of graphs are presented."
    },
    {
        "anchor": "Quark flavor physics and lattice QCD: For a long time, investigation into the weak interactions of quarks has\nguided us toward understanding the Standard Model we know today. Now in the era\nof high precision, these studies are still one of the most promising avenues\nfor peering beyond the Standard Model. This is a large-scale endeavour with\nmany tales and many protagonists. In these pages I follow a few threads of a\ncomplex story, those passing through the realm of lattice gauge theory.",
        "positive": "Dense but confined matter as a new state in QCD: Centre sector transitions in QCD-like theories with dynamical quark matter\nare investigated. In the hadronic phase, these transitions still take place in\nthe infinite volume at zero temperature limit despite of the explicit breaking\nof the centre symmetry by the matter fields. This finding is supported by\nsimulations of the SU(2) Yang-Mills theory with Higgs matter. The\nphenomenological impact of the centre sector transitions for dense but confined\nmatter is explained: centre dressed quarks acquire Bose statistics and form a\nso-called Fermi-Einstein condensate. This mechanism is further illustrated in\nthe Schwinger model where it solves the Silver-Blaze problem."
    },
    {
        "anchor": "The Quark-Hadron Transition in the Early Universe: We use recent lattice QCD outputs to work out the expansion law of the\nUniverse during the cosmological quark--hadron transition. To do so, a suitable\ntechnique to exploit both pressure and energy density data, with the related\nerror bars, is introduced. We also implement suitable techniques to relate the\nT range where lattice outputs are available with lower and higher T's, for\nwhich we test suitable expressions. We finally compare the cosmological\nbehavior found using lattice data with the one obtainable in the case the\ntransition were first order, although not so far from the crossover transition\nwe studied. Differences are small to be tested with cosmological data, but the\ncoming of the era of precision cosmology might open a channel to inspect the\nQCD transition through them.",
        "positive": "Pion and nucleon in two flavour QCD with unimproved Wilson fermions: We calculate pion mass, pion decay constant, PCAC quark mass and nucleon mass\nin two flavour lattice QCD with unimproved Wilson fermion and gauge actions.\nSimulations are performed using DD-HMC algorithm at two lattice spacings and\ntwo volumes for several values of the quark mass. The cutoff effects in pion\nmass and nucleon mass for the explored region of parameter space are found to\nbe negligible. The chiral behaviours of pion mass, pion decay constant and\nquark condensate are found to be qualitatively consistent with NLO chiral\nperturbation theory."
    },
    {
        "anchor": "A New Technique for Measuring the Strangemess Content of the Proton on\n  the Lattice: A new technique for computing the strangeness content of the proton on the\nlattice is described. It is applied to the calculation of the strange quark\ncontribution to the proton's spin, specifically to the evaluation of the proton\nmatrix element of the strange quark axial current. Preliminary results are not\nin disagreement with the EMC experiment. NOTE: This paper is available only in\npostscript form.",
        "positive": "Hybrid Quarkonia with Dynamical Sea Quarks: We present a dynamical lattice calculation with 2 flavours for bottomonium\nstates with an additional gluonic excitation. Using improved actions for the\nquarks and gauge fields at a lattice spacing of $a \\approx 0.1$ fm, we find\n10.977(61)(62) GeV for the energy of the lowest lying $b\\bar bg$-hybrid, where\nthe first error is statistical and the second denotes the systematic\nuncertainty due to the determination of scale. In a parallel quenched\nsimulation we demonstrate explicitly that vacuum polarisation effects are less\nthan 10% of the splitting with the ground state."
    },
    {
        "anchor": "Pion Form Factor with Overlap Fermion: We present a calculation of the pion form factor using overlap fermions on\n2+1-flavor domain-wall configurations on a $24^3\\times 64$ lattice with $a=0.11\n\\, {\\rm{fm}}$ and on a $32^3 \\times 64$ lattice with $a=0.143 \\, {\\rm{fm}}$\ngenerated by the RBC/UKQCD collaboration. Using the multi-mass algorithm, a\nsimulation has been done with various valence quark masses with a range of\nspace-like $Q^2$ from 0.0 to 0.6 ${\\rm{GeV^2}}$.",
        "positive": "Quark Confinement Physics from Quantum Chromodynamics: We show the construction of the dual superconducting theory for the\nconfinement mechanism from QCD in the maximally abelian (MA) gauge using the\nlattice QCD Monte Carlo simulation. We find that essence of infrared abelian\ndominance is naturally understood with the off-diagonal gluon mass $m_{\\rm off}\n\\simeq 1.2 {\\rm GeV}$ induced by the MA gauge fixing. In the MA gauge, the\noff-diagonal gluon amplitude is forced to be small, and the off-diagonal gluon\nphase tends to be random. As the mathematical origin of abelian dominance for\nconfinement, we demonstrate that the strong randomness of the off-diagonal\ngluon phase leads to abelian dominance for the string tension. In the MA gauge,\nthere appears the macroscopic network of the monopole world-line covering the\nwhole system. We investigate the monopole-current system in the MA gauge by\nanalyzing the dual gluon field $B_\\mu$. We evaluate the dual gluon mass as $m_B\n= 0.4 \\sim$ 0.5GeV in the infrared region, which is the lattice-QCD evidence of\nthe dual Higgs mechanism by monopole condensation. Owing to infrared abelian\ndominance and infrared monopole condensation, QCD in the MA gauge is\ndescribable with the dual Ginzburg-Landau theory."
    },
    {
        "anchor": "Impact of Dynamical Fermions on the Centre Vortex Gluon Propagator: The impact of $SU(3)$ centre vortices on the Landau-gauge gluon propagator is\ncalculated in the presence of dynamical fermions and compared to the pure\nYang-Mills case. The presence of dynamical fermions is found to alter the\nbehaviour of the centre vortex propagator when compared to the established\npure-gauge result. The gluon spectral representation is also explored from the\ncentre vortex perspective, where centre vortices are shown to exhibit clear\nsigns of positivity violation, which is an indicator of confinement. Vortex\nremoval subsequently restores positivity, demonstrating the crucial role centre\nvortices play in the confinement of gluons.",
        "positive": "Finite-element quantum field theory: An alternative approach to lattice gauge theory has been under development\nfor the past decade. It is based on discretizing the operator Heisenberg\nequations of motion in such a way as to preserve the canonical commutation\nrelations at each lattice site. It is now known how to formulate a non-Abelian\ngauge theory within this framework. The formulation appears to be free of\nfermion doubling. Since the theory is unitary, a time-development operator\n(Hamiltonian) can be constructed."
    },
    {
        "anchor": "Exact Zero-Modes of the Compact QED Dirac Operator: We calculate the low-lying eigenmodes of the Neuberger overlap-Dirac operator\nfor $4d$ compact lattice QED in the quenched approximation. In the strong\ncoupling phase we find exact zero-modes, quite similar as in non-Abelian\nlattice QCD. Subsequently we make an attempt to identify responsible\ntopological excitations of the U(1) lattice gauge theory.",
        "positive": "Critical couplings and string tensions via lattice matching of RG\n  decimations: We calculate critical couplings and string tensions in SU(2) and SU(3) pure\nlattice gauge theory by a simple and inexpensive technique of two-lattice\nmatching of RG block transformations. The transformations are potential moving\ndecimations generating plaquette actions with large number of group characters\nand exhibit rapid approach to a unique renormalized trajectory. Fixing the\ncritical coupling $\\beta_c(N_\\tau)$ at one value of temporal lattice length\n$N_\\tau$ by MC simulation, the critical couplings for any other value of\n$N_\\tau$ are then obtained by lattice matching of the block decimations. We\nobtain $\\beta_c(N_\\tau)$ values over the range $N_\\tau = 3 - 32$ and find\nagreement with MC simulation results to within a few percent in all cases. A\nsimilar procedure allows the calculation of string tensions with similarly good\nagreement with MC data."
    },
    {
        "anchor": "Transport Coefficients of Quark Gluon Plasma From Lattice Gauge Theory: Numerical results for the transport coefficients of quark gluon plasma are\nobtained by lattice simulations on on $16^3 \\times 8$ lattice with the quench\napproximation where we apply the gauge action proposed by Iwasaki. The bulk\nviscosity is consistent with zero, and the shear viscosity is slightly smaller\nthan the typical hadron masses. They are not far from the simple extrapolation\non the figure of perturbative calculation in high temperature limit down to $T\n\\sim T_{c}$. The gluon propagator in the confined and deconfined phases are\nalso discussed.",
        "positive": "The Massive Schwinger Model in a Fast Moving Frame: We present a non-perturbative study of the massive Schwinger model. We use a\nHamiltonian approach, based on a momentum lattice corresponding to a fast\nmoving reference frame, and equal time quantization."
    },
    {
        "anchor": "Gluon and ghost correlation functions of 2-color QCD at finite density: 2-color QCD, i. e. QCD with the gauge group SU(2), is the simplest\nnon-Abelian gauge theory without sign problem at finite quark density.\nTherefore its study on the lattice is a benchmark for other non-perturbative\napproaches at finite density. To provide such benchmarks we determine the\nminimal-Landau-gauge 2-point and 3-gluon correlation functions of the gauge\nsector and the running gauge coupling at finite density. We observe no\nsignificant effects, except for some low-momentum screening of the gluons at\nand above the supposed high-density phase transition.",
        "positive": "Magnetic field-induced gluonic (inverse) catalysis and pressure\n  (an)isotropy in QCD: We study the influence of strong external magnetic fields on gluonic and\nfermionic observables in the QCD vacuum at zero and nonzero temperatures, via\nlattice simulations with N_f=1+1+1 staggered quarks of physical masses. The\ngluonic action density is found to undergo magnetic catalysis at low\ntemperatures and inverse magnetic catalysis near and above the transition\ntemperature, similar to the quark condensate. Moreover, the gluonic action\ndevelops an anisotropy: the chromo-magnetic field parallel to the external\nfield is enhanced, while the chromo-electric field in this direction is\nsuppressed. We demonstrate that the same hierarchy is obtained using the\nEuler-Heisenberg effective action. Conversely, the topological charge density\ncorrelator does not reveal a significant anisotropy up to magnetic fields eB~1\nGeV^2. Furthermore, we show that the pressure remains isotropic even for\nnonzero magnetic fields, if it is defined through a compression of the system\nat fixed external field. In contrast, if the flux of the field is kept fixed\nduring the compression -- which is the situation realized in the lattice\nsimulation -- the pressure develops an anisotropy. We estimate the quark and\ngluonic contributions to this anisotropy, and relate them to the magnetization\nof the QCD vacuum. After performing electric charge renormalization, we obtain\nan estimate for the magnetization, which indicates that QCD is paramagnetic."
    },
    {
        "anchor": "The epsilon regime with Wilson fermions: We study the impact of explicit chiral symmetry breaking of Wilson fermions\non mesonic correlators in the epsilon-regime using Wilson chiral perturbation\ntheory (WChPT). We generalize the epsilon-expansion of continuum ChPT to\nnonzero lattice spacings for various quark mass regimes. It turns out that the\ncorrections due to a nonzero lattice spacing are highly suppressed for typical\nquark masses of the order aLambda_QCD^2. The lattice spacing effects become\nmore pronounced for smaller quark masses and lead to non-trivial corrections of\nthe continuum ChPT results at next-to-leading order. We compute these\ncorrections for the standard current and density correlation functions. A fit\nto lattice data shows that these corrections are small, as expected.",
        "positive": "Hadronic Structure, Conformal Maps, and Analytic Continuation: We present a method for analytic continuation of retarded Green functions,\nincluding Euclidean Green functions computed using lattice QCD. The method is\nbased on conformal maps and construction of an interpolation function which is\nanalytic in the upper half plane. A novel aspect of our method is rigorous\nbounding of systematic uncertainties, which are handled by constructing the\nfull space of interpolating functions (at each point in the upper half-plane)\nconsistent with the given Euclidean data and the constraints of analyticity.\nThe resulting Green function in the upper half-plane has an appealing\ninterpretation as a smeared spectral function."
    },
    {
        "anchor": "Connected and disconnected quark contributions to hadron spin: By introducing an external spin operator to the fermion action, the quark\nspin fractions of hadrons are determined from the linear response of the hadron\nenergies using the Feynman-Hellmann (FH) theorem. At our SU(3)-flavour\nsymmetric point, we find that the connected quark spin fractions are\nuniversally in the range 55-70\\% for vector mesons and octet and decuplet\nbaryons. There is an indication that the amount of spin suppression is quite\nsensitive to the strength of SU(3) breaking. We also present first preliminary\nresults applying the FH technique to calculations of quark-line disconnected\ncontributions to hadronic matrix elements of axial and tensor operators. At the\nSU(3)-flavour symmetric point we find a small negative contribution to the\nnucleon spin from disconnected quark diagrams, while the corresponding tensor\nmatrix elements are consistent with zero.",
        "positive": "Object-oriented implementation of algebraic multi-grid solver for\n  lattice QCD on SIMD architectures and GPU clusters: A portable implementation of elaborated algorithm is important to use variety\nof architectures in HPC applications. In this work we implement and benchmark\nan algebraic multi-grid solver for Lattice QCD on three different\narchitectures, Intel Xeon Phi, Fujitsu A64FX, and NVIDIA Tesla V100, in keeping\nhigh performance and portability of the code based on the object-oriented\nparadigm. Some parts of code are specific to an architecture employing\nappropriate data layout and tuned matrix-vector multiplication kernels, while\nthe implementation of abstract solver algorithm is common to all architectures.\nAlthough the performance of the solver depends on tuning of the\narchitecture-dependent part, we observe reasonable scaling behavior and better\nperformance than the mixed precision BiCGSstab solvers."
    },
    {
        "anchor": "A new method for a lattice calculation of $\u03b7_c \\rightarrow 2\u03b3$: We propose a direct method to calculate the decay width of a hadron decaying\nto two photons, which is conventionally obtained by an extrapolation for\nvarious off-shell form factors. The new method provides an simple way to\nexamine the finite-volune effects. As an example, we apply the method to\n$\\eta_c\\rightarrow 2\\gamma$. Using three $N_f=2$ twisted-mass gauge ensembles\nwith different lattice spacings, we obtain the final decay width\n$\\Gamma_{\\eta_c\\gamma\\gamma}=6.57(15)_{\\textrm{stat}}(8)_{\\textrm{syst}}$ keV,\nwhere the systematic error accounts for the fine-tuning of the charm quark\nmass. This method can also be applied for other processes which involve the\nleptonic or radiative particles in the final states.",
        "positive": "Lefschetz-thimble approach to the Silver Blaze problem of one-site\n  fermion model: The sign problem of finite-density QCD at the zero temperature becomes very\nsevere if the quark chemical potential exceeds half of the pion mass. In order\nto understand its property, we consider the sign problem of the one-site\nfermion model appearing in its path-integral expression by using the\nLefschetz-thimble method. We show that the original integration cycle becomes\ndecomposed into multiple Lefschetz thimbles at a certain value of the fermion\nchemical potential, which would correspond to half of the pion mass of\nfinite-density QCD. This triggers a fictitious phase transition on each\nLefschetz thimble, and the interference of complex phases among them plays an\nimportant role for the correct description of the system. We also show that the\ncomplex Langevin method does not work in this situation."
    },
    {
        "anchor": "Color-Flavor Transformation for the Special Unitary Group: We extend Zirnbauer's color-flavor transformation in the fermionic sector to\nthe case of the special unitary group. The transformation allows a certain\nintegral over SU(N_c) color matrices to be transformed into an integral over\nflavor matrices which parameterize the coset space U(2N_f)/U(N_f)xU(N_f).\nIntegrals of the type considered appear, for example, in the partition function\nof lattice gauge theory.",
        "positive": "Nucleon axial, scalar, and tensor charges using lattice QCD at the\n  physical pion mass: We report on lattice QCD calculations of the nucleon isovector axial, scalar,\nand tensor charges. Our calculations are performed on two 2+1-flavor ensembles\ngenerated using a 2-HEX-smeared Wilson-clover action at the physical pion mass\nand lattice spacings $a\\approx$ 0.116 and 0.093 fm. We use a wide range of\nsource-sink separations - eight values ranging from roughly 0.4 to 1.4 fm on\nthe coarse ensemble and three values from 0.9 to 1.5 fm on the fine ensemble -\nwhich allows us to perform an extensive study of excited-state effects using\ndifferent analysis and fit strategies. To determine the renormalization\nfactors, we use the nonperturbative Rome-Southampton approach and compare\nRI'-MOM and RI-SMOM intermediate schemes to estimate the systematic\nuncertainties. Our final results are computed in the MS-bar scheme at scale 2\nGeV. The tensor and axial charges have uncertainties of roughly 4%,\n$g_T=0.972(41)$ and $g_A=1.265(49)$. The resulting scalar charge,\n$g_S=0.927(303)$, has a much larger uncertainty due to a stronger dependence on\nthe choice of intermediate renormalization scheme and on the lattice spacing."
    },
    {
        "anchor": "Position space method for the nucleon magnetic moment in lattice QCD: The extraction of the magnetic form factor of the nucleon at zero momentum\ntransfer is usually performed by adopting a parametrization for its momentum\ndependence and fitting the results obtained at finite momenta. We present a\nposition space method that allows us to remove the momentum prefactor in the\nform factor decomposition and hence compute the magnetic form factor directly\nat zero momentum without the need to assume a functional form for its momentum\ndependence. The method is explored on one ensemble using $N_f=2+1+1$ Wilson\ntwisted mass fermions with a light quark mass corresponding to\n$M_\\pi\\approx373\\mathrm{GeV}$ and a lattice spacing of\n$a\\approx0.082\\mathrm{fm}$. We obtain results for the isovector magnetic moment\nand for the proton and neutron magnetic moments. The value we find for the\nisovector magnetic moment is larger as compared to fitting the form factor at\nthe discrete values of the lattice momentum transfers using a dipole Ansatz,\nbringing it closer to the experimental value.",
        "positive": "Feasibility of Diagrammatic Monte-Carlo based on weak-coupling expansion\n  in asymptotically free theories: case study of $O(N)$ sigma-model in the\n  large-$N$ limit: We discuss the feasibility of applying Diagrammatic Monte-Carlo algorithms to\nthe weak-coupling expansions of asymptotically free quantum field theories,\ntaking the large-$N$ limit of the $O(N)$ sigma-model as the simplest example\nwhere exact results are available. We use stereographic mapping from the sphere\nto the real plane to set up the perturbation theory, which results in a small\nbare mass term proportional to the coupling $\\lambda$. Counting the powers of\ncoupling associated with higher-order interaction vertices, we arrive at the\ndouble-series representation for the dynamically generated mass gap in powers\nof both $\\lambda$ and $\\log(\\lambda)$, which converges quite quickly to the\nexact non-perturbative answer. We also demonstrate that it is feasible to\nobtain the coefficients of these double series by a Monte-Carlo sampling in the\nspace of Feynman diagrams. In particular, the sign problem of such sampling\nbecomes milder at small $\\lambda$, that is, close to the continuum limit."
    },
    {
        "anchor": "The strength of the electroweak phase transition at $m_H \\approx$ 80 GeV: In this letter we present the results of our numerical simulations for the\nfinite temperature electroweak phase transition using the SU(2)-Higgs model on\nfour-dimensional lattices at $m_H \\approx 80$ GeV. The temporal extension\n$L_t=2$ is used for asymmetric lattice spacings with an asymmetry parameter\n$a_s/a_t \\approx 4$. The measured thermodynamical quantities (interface\ntension, jump of the order parameter and latent heat) suggest that the phase\ntransition is of very weakly first order.",
        "positive": "NRQCD based S- and P-wave bottomonium spectra at finite temperature from\n  $48^3 \\times 12$ lattices with $N_f=2+1$ light HISQ flavors: We study S-wave and P-wave bottomonium spectral functions at non-zero\ntemperature in 2+1 flavor QCD using the NRQCD formulation for bottom quarks. We\nuse a novel Bayesian approach to reconstruct the spectral functions and find\nthat $\\chi_{b1}$ survives up to $T=249 {\\rm MeV}$. We also study the effect of\ndifferent temporal discretizations of the NRQCD formalism on the bottomonium\ncorrelation functions"
    },
    {
        "anchor": "Thermal evolution of the Schwinger model with Matrix Product Operators: We demonstrate the suitability of tensor network techniques for describing\nthe thermal evolution of lattice gauge theories. As a benchmark case, we have\nstudied the temperature dependence of the chiral condensate in the Schwinger\nmodel, using matrix product operators to approximate the thermal equilibrium\nstates for finite system sizes with non-zero lattice spacings. We show how\nthese techniques allow for reliable extrapolations in bond dimension, step\nwidth, system size and lattice spacing, and for a systematic estimation and\ncontrol of all error sources involved in the calculation. The reached values of\nthe lattice spacing are small enough to capture the most challenging region of\nhigh temperatures and the final results are consistent with the analytical\nprediction by Sachs and Wipf over a broad temperature range.",
        "positive": "Potential between adjoint sources in arbitrary representations: The potential between sources in arbitrary representations of the gauge group\nis studied on an anisotropic lattice in a spherical model approximation. It is\nshown analytically that for half-integer $j$ and $j'$ in the confinement phase\nthe potential rises linearly, whereas for integer $j$ and half-integer $j'$ it\nrises infinitely which means a strong suppression of the combination of such\nstates . For integer $j$ and $j'$ the potential shows Debay screening and\nCoulomb behavior in the deconfinement phase >. It is also shown, that\n$<\\chi^{(j)}> \\backsim <\\chi>^{2j}$ when $<\\chi> \\gtrsim1$ and is in agreement\nwith the mean field theory prediction, and $<\\chi^{(j)}> \\backsim <\\chi>$ for\n$<\\chi> \\lesssim1$ which agrees with MC experiment. String tension\nmodel-computed for sources invariant under center group transformations\ndemonstrates Casimir scaling in the intermediate distance regime and turns into\nzero at large distances."
    },
    {
        "anchor": "Critical Behaviour of the 3d Gross-Neveu and Higgs-Yukawa Models: We measure the critical exponents of the three dimensional Gross-Neveu model\nwith two four-component fermions. The exponents are inferred from the scaling\nbehaviour of observables on different lattice sizes. We also calculate the\nexponents, through a second order epsilon-expansion around 4d, for the three\ndimensional Higgs-Yukawa model, which is expected to be in the same\nuniversality class and we find that the exponents agree. We conclude that the\nequivalence of the two models remains valid in 3d at fixed small N_f values.",
        "positive": "Preliminary study of $B_B$ parameter using Lattice NRQCD: We present the preliminary result of the calculation of $B_B$ parameter using\nlattice NRQCD. The calculation is performed on a $16^3 \\times 48$ quenched\nlattice at $\\beta=5.9$ with clover light quark. The use of lattice NRQCD\nenables us to investigate the $1/m_Q$ correction from the static limit. The\nobserved mass dependence is well described by the vacuum saturation."
    },
    {
        "anchor": "The $\u0394_{mix}$ parameter in the overlap on domain-wall mixed action: A direct calculation of the mixed-action parameter $\\Delta_{mix}$ with\nvalence overlap fermions on a domain-wall fermion sea is presented. The\ncalculation is performed on four ensembles of the 2+1-flavor domain-wall gauge\nconfigurations: $24^3 \\times 64$ ($a m_l= 0.005$, $a=0.114\\fm$) and $32^3\n\\times 64$ ($a m_l = 0.004, 0.006, 0.008$, $a=0.085\\fm$). For pion masses close\nto $300\\MeV$ we find \\hbox{$\\Delta_{mix}=0.030(6)\\GeV^4$} at $a=0.114\\fm$ and\n$\\Delta_{mix}=0.033(12)\\GeV^4$ at $a=0.085\\fm$. The results are quite\nindependent of the lattice spacing and they are significantly smaller than the\nresults for valence domain-wall fermions on Asqtad sea or those of valence\noverlap fermions on clover sea. Combining the results extracted from these two\nensembles, we get $\\Delta_{mix}=0.030(6)(5)\\GeV^4$, where the first error is\nstatistical and the second is the systematic error associated with the fitting\nmethod.",
        "positive": "First-principle calculation of $\u03b7_c\\rightarrow 2\u03b3$ decay width\n  from lattice QCD: We perform a lattice QCD calculation of the $\\eta_c\\to2\\gamma$ decay width\nusing a model-independent method that requires no momentum extrapolation of the\noff-shell form factors. This method also provides a straightforward and simple\nway to examine the finite-volume effects. The calculation is accomplished using\n$N_f=2$ twisted mass fermion ensembles. The statistically significant\nexcited-state effects are observed and eliminated using a multi-state fit.The\nimpact of fine-tuning the charm quark mass is also examined and confirmed to be\nwell-controlled. Finally, using three lattice spacings for the continuum\nextrapolation, we obtain the decay width\n$\\Gamma_{\\eta_c\\gamma\\gamma}=6.67(16)_{\\mathrm{stat}}(6)_{\\mathrm{syst}}$ keV,\nwhich differs significantly from the Particle Data Group's reported value of\n$\\Gamma_{\\eta_c\\gamma\\gamma}=5.4(4)$ keV (2.9~$\\sigma$ tension). We provide\ninsight into the comparison between our findings, previous theoretical\npredictions, and experimental measurements."
    },
    {
        "anchor": "Analytical studies of the complex Langevin equation with a Gaussian\n  Ansatz and multiple solutions in the unstable region: We investigate a simple model using the numerical simulation in the complex\nLangevin equation (CLE) and the analytical approximation with the Gaussian\nAnsatz. We find that the Gaussian Ansatz captures the essential and even\nquantitative features of the CLE results quite well including unwanted behavior\nin the unstable region where the CLE converges to a wrong answer. The Gaussian\nAnsatz is therefore useful for looking into this convergence problem and we\nfind that the exact answer in the unstable region is nicely reproduced by\nanother solution that is naively excluded from the stability condition. We\nconsider the Gaussian probability distributions corresponding to multiple\nsolutions along the Lefschetz thimble to discuss the stability and the\nlocality. Our results suggest a prescription to improve the convergence of the\nCLE simulation to the exact answer.",
        "positive": "Testing the stochastic LapH method in the twisted mass formulation: We present first results using the stochastic Laplace-Heaviside (sLapH)\nmethod in the twisted mass formulation. The calculations are performed on gauge\nconfigurations provided by the European Twisted Mass (ETM) collaboration with\n2+1+1 dynamical quark flavours at a single value of the lattice spacing. In\nparticular, we compute disconnected contributions to flavour singlet\npseudo-scalar mesons and compare sLapH to standard volume noise methods."
    },
    {
        "anchor": "Sign optimization and complex saddle points in one-dimensional QCD: We study one-dimensional QCD at finite quark density by using the sign\noptimization framework. The fermion sign problem is mitigated by deforming the\npath integral domain, $SU(3)$ to a complexified one ${\\cal M} \\subset SL(3)$,\nexplicitly constructed to reduce the phase fluctuations. The complexification\nis constructed using the angular representation of $SU(3)$. We provide a\nphysical explanation of the optimization procedure in terms of complex saddle\npoints. This picture connects the sign optimization framework to the\ngeneralized Lefschetz thimbles.",
        "positive": "K-string tensions at finite temperature and integrable models: It has recently been pointed out that simple scaling properties of Polyakov\ncorrelation functions of gauge systems in the confining phase suggest that the\nratios of k-string tensions in the low temperature region is constant up to\nterms of order T^3. Here we argue that, at least in a three-dimensional Z_4\ngauge model, the above ratios are constant in the whole confining phase. This\nresult is obtained by combining numerical experiments with known exact results\non the mass spectrum of an integrable two-dimensional spin model describing the\ninfrared behaviour of the gauge system near the deconfining transition."
    },
    {
        "anchor": "Preliminary lattice study of the I=1 $K \\bar{K}$ scattering length: The s-wave kaon-antikaon ($K \\bar{K}$) elastic scattering length is\ninvestigated by lattice simulation using pion masses $m_\\pi = 330 - 466$ MeV.\nThrough moving wall sources without gauge fixing, we calculate $K \\bar{K}$\nfour-point correlation functions for isospin I=1 channel in the \"Asqtad\"\nimproved staggered fermion formulation, and observe a clear signal of\nattraction, which is consistent with other pioneering lattice studies on $K\n\\bar{K}$ potential. Extrapolating $K \\bar{K}$ scattering length to the physical\npoint, we obtain $m_{K} a^{I=1}_{K\\bar{K}} = 0.211(33)$. These simulations are\nperformed with MILC gauge configurations at lattice spacing $a \\approx 0.15$\nfm.",
        "positive": "Varieties and properties of central-branch Wilson fermions: We focus on the four-dimensional central-branch Wilson fermion, which makes\ngood use of six species at the central branch of the Wilson Dirac spectrum and\npossesses the extra $U(1)_{\\overline V}$ symmetry. With introducing new\ninsights we discuss the prohibition of additive mass renormalization for all\nthe six species, SSB of $U(1)_{\\overline V}$ in strong-coupling QCD, the\nabsence of the sign problem, and the usefulness for many-flavor QCD simulation.\nWe then construct several varieties of the central-branch fermions and study\ntheir properties. In particular, we investigate the two-flavor version, where\nthe Dirac spectrum has seven branches and two species live at the central\nbranch. Although the hypercubic symmetry is broken, the other symmetries are\nthe same as those of the original one. We study this setup in terms of lattice\nperturbation theory, strong-coupling QCD, the absence of sign problem, and the\nparameter tuning for Lorentz symmetry restoration. By comparing the properties\nof the original and two-flavor version, we find that the existence of\nhypercubic symmetry as well as $U(1)_{\\overline V}$ is essential for the\nabsence of additive mass renormalization of all the central-branch species. As\nthe other two-flavor version, we investigate the central-branch\nstaggered-Wilson fermion, which is obtained from the eight-flavor\ncentral-branch Wilson fermion via spin diagonalization. We argue that it is\nfree from any additive mass renormalization and is regarded as a minimally\ndoubled fermion with less symmetry breaking."
    },
    {
        "anchor": "Relativistic Bottomonium Spectrum from Anisotropic Lattices: We report on a first relativistic calculation of the quenched bottomonium\nspectrum from anisotropic lattices. Using a very fine discretisation in the\ntemporal direction we were able to go beyond the non-relativistic approximation\nand perform a continuum extrapolation of our results from five different\nlattice spacings (0.04-0.17 fm) and two anisotropies (4 and 5). We investigate\nseveral systematic errors within the quenched approximation and compare our\nresults with those from non-relativistic simulations.",
        "positive": "Status of the QCDSP project: We describe the completed 8,192-node, 0.4Tflops machine at Columbia as well\nas the 12,288-node, 0.6Tflops machine assembled at the RIKEN Brookhaven\nResearch Center. Present performance as well as our experience in commissioning\nthese large machines is presented. We outline our on-going physics program and\nexplain how the configuration of the machine is varied to support a wide range\nof lattice QCD problems, requiring a variety of machine sizes. Finally a brief\ndiscussion is given of future prospects for large-scale lattice QCD machines."
    },
    {
        "anchor": "Induced QCD with two auxiliary bosonic fields: Following a proposal of Budczies and Zirnbauer, we investigate an alternative\nlattice discretization of continuum ${\\rm SU}(N_c)$ Yang-Mills theory in which\nthe self-interactions of the gauge field are induced by a path integral over\n$N_b\\ge N_c-1$ auxiliary bosonic fields which are coupled linearly to the gauge\nfield. In two dimensions there exists an analytic proof that the new\ndiscretization reproduces Yang-Mills theory in its non-perturbative continuum\nlimit. We provide numerical evidence that this is also the case in three and\nfour dimensions and that, after a suitable matching of the free parameters, the\nresults of the induced theory agree with results from the ordinary plaquette\naction up to lattice artifacts. The new discretization is ideally suited to\nchange the order of integration in the QCD path integral to arrive at\nformulations in which the gauge fields have been integrated out. The resulting\ntheories might be amenable to methods previously used in the infinite-coupling\nlimit, and we briefly discuss possibilities to arrive at dual representations\nof lattice QCD.",
        "positive": "Precise determination of the lattice spacing in full lattice QCD: We compare three different methods to determine the lattice spacing in\nlattice QCD and give results from calculations on the MILC ensembles of\nconfigurations that include the effect of $u$, $d$ and $s$ sea quarks. It is\nuseful, for ensemble to ensemble comparison, to express the results as giving a\nphysical value for $r_1$, a parameter from the heavy quark potential. Combining\nthe three methods gives a value for $r_1$ in the continuum limit of\n0.3133(23)(3) fm. Using the MILC values for $r_0/r_1$, this corresponds to a\nvalue for the $r_0$ parameter of 0.4661(38) fm. We also discuss how to use the\n$\\eta_s$ for determining the lattice spacing and tuning the $s$-quark mass\naccurately, by giving values for $m_{\\eta_s}$ (0.6858(40) GeV) and $f_{\\eta_s}$\n(0.1815(10) GeV)."
    },
    {
        "anchor": "On the Implementation of General Background Electromagnetic Fields on a\n  Periodic Hypercubic Lattice: Nonuniform background electromagnetic fields, once implemented in lattice\nquantum chromodynamics calculations of hadronic systems, provide a means to\nconstrain a large class of electromagnetic properties of hadrons and nuclei,\nfrom their higher electromagnetic moments and charge radii to their\nelectromagnetic form factors. We show how nonuniform fields can be constructed\non a periodic hypercubic lattice under certain conditions and determine the\nprecise form of the background U(1) gauge links that must be imposed on the\nquantum chromodynamics gauge-field configurations to maintain periodicity. Once\nsupplemented by a set of quantization conditions on the background-field\nparameters, this construction guarantees that no nonuniformity occurs in the\nhadronic correlation functions across the boundary of the lattice. The special\ncases of uniform electric and magnetic fields, a nonuniform electric field that\nvaries linearly in one spatial coordinate (relevant to the determination of\nquadruple moment and charge radii), nonuniform electric and magnetic fields\nwith given temporal and spatial dependences (relevant to the determination of\nnucleon spin polarizabilities) and plane-wave electromagnetic fields (relevant\nto the determination of electromagnetic form factors) are discussed explicitly.",
        "positive": "Pseudoscalar flavor-singlets and staggered fermions: The Asqtad improved staggered fermion formalism has been a valuable tool in\nsuccessfully calculating the non-singlet parts of the hadronic spectrum. We are\nengaged in a project to calculate the spectrum of the pseudoscalar singlet\nmesons with 2+1-flavor Asqtad staggered gauge configurations. Propagators of\nflavor-singlet states incorporate contributions from both disconnected and\nconnected diagrams, and hence are sensitive to any differences in the actions\ngoverning the sea and valence fermions on the lattice. As such, they also\npresent the possibility of a probe of the validity of the ``fourth-root trick''\nin the staggered fermion formulation. We present an update on our progress\ntoward measuring the $\\eta'$ mass on 2+1-flavor Asqtad staggered gauge\nconfigurations, including a review of methods and preliminary results. We also\nshow a strong correlation between ${\\rm Tr}(\\gamma_5\\otimes 1)$ and the\ntopological charge in these configurations, as predicted by the index theorem."
    },
    {
        "anchor": "The hadronic contribution to the running of the electromagnetic coupling\n  and electroweak mixing angle: As present and future experiments, on both the energy and precision\nfrontiers, look to identify new physics beyond the Standard Model, we require\nmore precise determinations of fundamental quantities, like the QED and\nelectroweak couplings at various momenta. These can be obtained either entirely\nfrom experimental measurements, or from one such measurement at a particular\nvirtuality combined with the couplings' virtuality dependence computed within\nthe SM. Thus, a precise, entirely theoretical determination of the running\ncouplings is highly desirable, even more since the preliminary results of the\nE989 experiment in Fermilab were published. We give results for the hadronic\ncontribution to the QED running coupling $\\alpha(Q^2)$ and weak mixing angle\n$\\sin^2\\theta_W(Q^2)$ in the space-like energy region $(0, 7]~\\text{GeV}^2$\nwith a total relative uncertainty of $2\\%$ at energies $Q^2 \\ll\n1~\\text{GeV}^2$, and $1\\%$ at $Q^2 > 1~\\text{GeV}^2$.",
        "positive": "On complex Langevin dynamics and zeroes of the measure I: Formal proof\n  and simple models: In the complex Langevin approach to lattice simulations at nonzero density,\nzeroes of the fermion determinant lead to a meromorphic drift and hence a need\nto revisit the theoretical derivation. We discuss how poles in the drift affect\nthe formal justification of the approach and then explore the various potential\nissues in simple models, in a manner that is applicable to heavy dense and full\nQCD."
    },
    {
        "anchor": "Analytical study of fermion determinant and chiral condensate behavior\n  at finite temperatures in toy model approximation: Fermion determinant is computed analytically on extremely large lattices $%\nN_\\tau \\to \\infty $ in the toy model approximation in which action is truncated\nso that in the Hamiltonian limit of $a_\\tau \\to 0$ all terms of order $a_\\tau\n/a_\\sigma $ are discarded$.$ Chiral condensate is studied in the area of small\n($m<<T$) quark masses.",
        "positive": "Zero temperature lattice Weinberg - Salam model for the values of the\n  cutoff $\u039b\\sim 1$ TeV: The lattice Weinberg - Salam model at zero temperature is investigated\nnumerically. We consider the model for the following values of the coupling\nconstants: the Weinberg angle $\\theta_W \\sim 30^o$, the fine structure constant\n$\\alpha \\sim 1/150$, the Higgs mass $M_H \\sim 150$ GeV. We find that the\nfluctuational region begins at the values of the cutoff $\\Lambda$ above about\n0.8 TeV. In this region the average distance between Nambu monopoles is close\nto their sizes. At $\\Lambda > 1$ TeV the Nambu monopole currents percolate.\nWithin the fluctuational region the considered definitions of the scalar field\ncondensate give values that differ from the expected one $2 M_Z/g_z$. We\nconsider the given results as an indication that the nonperturbative effects\nmay be present in the Weinberg - Salam model at the large values of the cutoff.\nOur numerical results were obtained on the lattices of sizes up to $16^3\\times\n32$."
    },
    {
        "anchor": "Non-perturbative renormalisation with interpolating momentum schemes: Hadronic matrix elements evaluated on the lattice can be converted to a\ncontinuum scheme such as $\\MSbar$ using intermediate non-perturbative\nrenormalisation schemes. Discretisation effects on the lattice and convergence\nof the continuum perturbation theory are both scheme dependent and we explore\nthis dependence in the framework of the Rome-Southampton method for generalised\nkinematics. In particular, we implement several non-exceptional {\\em\ninterpolating} momentum schemes, where the momentum transfer is {\\em not}\nrestricted to the symmetric point defined in RI/SMOM. Using flavour non-singlet\nquark bilinears, we compute the renormalisation factors of the quark mass and\nwave function for $N_f=3$ flavours of dynamical quarks. We investigate the\nperturbative and non-perturbative scale-dependencies. Our numerical results are\nobtained from lattice simulations performed with Domain-Wall fermions, based on\nensembles generated by RBC-UKQCD collaborations; we use two different lattice\nspacings $1/a \\sim 1.79 $ and $2.38$ GeV. We also give the numerical values for\nthe relevant anomalous dimensions and matching coefficients at\nnext-to-next-to-leading order.",
        "positive": "The four-gluon vertex in Landau gauge: The Landau gauge four-gluon vertex is studied using high statistical lattice\nsimulations for several momentum configurations. Furthermore, the outcome of\nthe lattice QCD simulations is compared with calculations performed with\ncontinuum Schwinger-Dyson equations."
    },
    {
        "anchor": "Quantum computation of thermal averages in the presence of a sign\n  problem: We illustrate the application of Quantum Computing techniques to the\ninvestigation of the thermodynamical properties of a simple system, made up of\nthree quantum spins with frustrated pair interactions and affected by a hard\nsign problem when treated within classical computational schemes. We show how\nquantum algorithms completely solve the problem, and discuss how this can apply\nto more complex systems of physical interest, with emphasis on the possible\nsystematics and on their control.",
        "positive": "$Sp(2N)$ Lattice Gauge Theories and Extensions of the Standard Model of\n  Particle Physics: We review the current status of the long-term programme of numerical\ninvestigation of $Sp(2N)$ gauge theories with and without fermionic matter\ncontent. We start by introducing the phenomenological as well as theoretical\nmotivations for this research programme, which are related to composite Higgs\nmodels, models of partial top compositeness, dark matter models, and in general\nto the physics of strongly coupled theories and their approach to the large-N\nlimit. We summarise the results of lattice studies conducted so far in the\n$Sp(2N)$ Yang-Mills theories, measuring the string tension, the mass spectrum\nof glueballs and the topological susceptibility, and discuss their large-N\nextrapolation. We then focus our discussion on $Sp(4)$, and summarise numerical\nmeasurements of mass and decay constant of mesons in the theories with fermion\nmatter in either the fundamental or the antisymmetric representation, first in\nthe quenched approximation, and then with dynamical fermions. We finally\ndiscuss the case of dynamical fermions in mixed representations, and exotic\ncomposite fermion states such as the chimera baryons. We conclude by sketching\nthe future stages of the programme. And we describe our approach to open\naccess."
    },
    {
        "anchor": "Non-Goldstone pion masses with NLO in Staggered Chiral Perturbation\n  Theory: We present results of the masses of taste non-Goldstone $(F \\ne \\xi_5)$ pions\nand kaons calculated up to the next-to-leading order in the SU(3) staggered\nchiral perturbation theory (SChPT). The results can be used to fit data and to\nunderstand taste symmetry breaking effect quantitatively. The final expressions\nfor the non-Goldstone masses contain 20 low energy constants unique to the\nnon-Goldstone sector. We have calculated the several cases such as the full\nQCD, partially quenched QCD, and quenched QCD in the $N_f=1+1+1$ flavor and\n$N_f=2+1$ flavor cases in the SU(3) and SU(2) SChPT. In this paper, we present\nonly the SU(3) part.",
        "positive": "Topology of the $O(3)$ non-linear sigma model under the gradient flow: The $O(3)$ non-linear sigma model (NLSM) is a prototypical field theory for\nQCD and ferromagnetism, and provides a simple system in which to study\ntopological effects. In lattice QCD, the gradient flow has been demonstrated to\nremove ultraviolet singularities from the topological susceptibility. In\ncontrast, lattice simulations of the NLSM find that the topological\nsusceptibility diverges in the continuum limit, even in the presence of the\ngradient flow. We introduce a $\\theta$-term and analyze the topological charge\nas a function of $\\theta$ under the gradient flow. Our results show that\ndivergence persists in the presence of the flow, even at non-zero $\\theta$."
    },
    {
        "anchor": "Rho resonance, timelike pion form factor, and implications for lattice\n  studies of the hadronic vacuum polarisation: We study isospin-1 P-wave $\\pi\\pi$ scattering in lattice QCD with two\nflavours of O($a$) improved Wilson fermions. For pion masses ranging from\n$m_\\pi=265$ MeV to $m_\\pi=437$ MeV, we determine the energy spectrum in the\ncentre-of-mass frame and in three moving frames. We obtain the scattering phase\nshifts using L\\\"uscher's finite-volume quantisation condition. Fitting the\ndependence of the phase shifts on the scattering momentum to a Breit-Wigner\nform allows us to determine the resonance parameters $m_\\rho$ and\n$g_{\\rho\\pi\\pi}$. By combining the scattering phase shifts with the decay\nmatrix element of the vector current, we calculate the timelike pion form\nfactor, $F_\\pi$, and compare the results to the Gounaris-Sakurai representation\nof the form factor in terms of the resonance parameters. In addition, we fit\nour data for the form factor to the functional form suggested by the Omn\\`es\nrepresentation, which allows for the extraction of the charge radius of the\npion. As a further application, we discuss the long-distance behaviour of the\nvector correlator, which is dominated by the two-pion channel. We reconstruct\nthe long-distance part in two ways: one based on the finite-volume energies and\nmatrix elements and the other based on $F_\\pi$. It is shown that this part can\nbe accurately constrained using the reconstructions, which has important\nconsequences for lattice calculations of the hadronic vacuum polarisation\ncontribution to the muon anomalous magnetic moment.",
        "positive": "Towards the heavy dense QCD phase diagram using Complex Langevin\n  simulations: Monte Carlo methods cannot probe far into the QCD phase diagram with a real\nchemical potential, due to the famous sign problem. Complex Langevin\nsimulations, using adaptive step-size scaling and gauge cooling, are suited for\nsampling path integrals with complex weights. We report here on tests of the\ndeconfinement transition in pure Yang-Mills SU(3) simulations and present an\nupdate on the QCD phase diagram in the limit of heavy and dense quarks."
    },
    {
        "anchor": "Hadron interactions from lattice QCD: Studies on hadron interactions from lattice QCD are reviewed. The $S$-wave\n$\\pi\\pi$ scattering lengths of the I=0 and I=2 channels are extracted from\nvarious lattice determinations of low energy constants in $N_f=2$ chiral\nperturbation theory. The results agree with each other and agree also with\nother non-lattice estimates. Recently the $P$-wave $\\pi\\pi$ scattering phase\nshift for the I=1 channel has been calculated. A preliminary estimate of the\n$\\rho$ meson decay width from the phase shift is consistent with the\nexperimental value. Two approaches to potentials between hadrons are discussed.\nOne is a method using static quarks to define the distance between two hadrons.\nThe other is a method to define a potential from a wave function of two\nhadrons. An application of the latter to the nucleon-nucleon ($NN$) potential\nturns out to reproduce qualitative features of the phenomenological $NN$\npotential such as attraction at long distance and repulsion at short distance.\nTheoretical issues of this approach are also discussed.",
        "positive": "Towards Lefschetz thimbles regularization of heavy-dense QCD: At finite density, lattice simulations are hindered by the well-known sign\nproblem: for finite chemical potentials, the QCD action becomes complex and the\nBoltzmann weight $e^{-S}$ cannot be interpreted as a probability distribution\nto determine expectation values by Monte Carlo techniques. Different\nworkarounds have been devised to study the QCD phase diagram, but their\napplication is mostly limited to the region of small chemical potentials. The\nLefschetz thimbles method takes a new approach in which one complexifies the\ntheory and deforms the integration paths. By integrating over Lefschetz\nthimbles, the imaginary part of the action is kept constant and can be factored\nout, while $e^{-Re(S)}$ can be interpreted as a probability measure. The method\nhas been applied in recent years to more or less difficult problems. Here we\nreport preliminary results on Lefschetz thimbles regularization of heavy-dense\nQCD. While still simple, this is a very interesting problem. It is a first look\nat thimbles for QCD, although in a simplified, effective version. From an\nalgorithmic point of view, it is a nice ground to test effectiveness of\ntechniques we developed for multi thimbles simulations."
    },
    {
        "anchor": "The chiral transition and U(1)_A symmetry restoration from lattice QCD\n  using Domain Wall Fermions: We present results on both the restoration of the spontaneously broken chiral\nsymmetry and the effective restoration of the anomalously broken U(1)_A\nsymmetry in finite temperature QCD at zero chemical potential using lattice\nQCD. We employ domain wall fermions on lattices with fixed temporal extent\nN_\\tau = 8 and spatial extent N_\\sigma = 16 in a temperature range of T = 139 -\n195 MeV, corresponding to lattice spacings of a \\approx 0.12 - 0.18 fm. In\nthese calculations, we include two degenerate light quarks and a strange quark\nat fixed pion mass m_\\pi = 200 MeV. The strange quark mass is set near its\nphysical value. We also present results from a second set of finite temperature\ngauge configurations at the same volume and temporal extent with slightly\nheavier pion mass. To study chiral symmetry restoration, we calculate the\nchiral condensate, the disconnected chiral susceptibility, and susceptibilities\nin several meson channels of different quantum numbers. To study U(1)_A\nrestoration, we calculate spatial correlators in the scalar and pseudo-scalar\nchannels, as well as the corresponding susceptibilities. Furthermore, we also\nshow results for the eigenvalue spectrum of the Dirac operator as a function of\ntemperature, which can be connected to both U(1)_A and chiral symmetry\nrestoration via Banks-Casher relations.",
        "positive": "Windows on the hadronic vacuum polarisation contribution to the muon\n  anomalous magnetic moment: An accurate determination of the leading-order hadronic vacuum polarisation\n(HVP) contribution to the anomalous magnetic moment of the muon is critical to\nunderstanding the size and significance of any discrepancy between the Standard\nModel prediction and experimental results being obtained by the Muon g-2\nexperiment at Fermilab. The Standard Model prediction is currently based on a\ndata-driven approach to the HVP using experimental results for\n$\\sigma(e^+e^-\\rightarrow\\,\\mathrm{hadrons})$. Lattice QCD aims to provide a\nresult with similar uncertainty from calculated vector-vector correlation\nfunctions, but the growth of statistical and systematic errors in the $u/d$\nquark correlation functions at large Euclidean time has made this difficult to\nachieve. We show that restricting the lattice contributions to a one-sided\nwindow $0<t<t_1$ can greatly improve lattice results while still capturing a\nlarge fraction of the total HVP. We illustrate this by comparing windowed\nlattice results based on the 2019 Fermilab Lattice/HPQCD/MILC HVP analysis with\ncorresponding results obtained from the KNT19 analysis of $R_{e^+e^-}$ data.\nFor $t_1=1.5$ fm, 70% of the total HVP is contained within the window and our\nlattice result has an error of~0.7%, only about twice as big as the error from\nthe $e^+e^-$~analysis. We see a tension of 2.7$\\sigma$ between the two results.\nWith increased statistics in the lattice data the one-sided windows will allow\nstringent tests of lattice and $R_{e^+e^-}$ results that include a large\nfraction of the total HVP contribution."
    },
    {
        "anchor": "Lattice Monte Carlo calculations for unitary fermions in a finite box: We perform lattice Monte Carlo simulations for up to 66 unitary fermions in a\nfinite box using a highly improved lattice action for nonrelativistic spin 1/2\nfermions. We obtain a value of $0.366^{+0.016}_{-0.011}$ for the Bertsch\nparameter, defined as the energy of the unitary Fermi gas measured in units of\nthe free gas energy in the thermodynamic limit. In addition, for up to four\nunitary fermions, we compute the spectrum of the lattice theory by exact\ndiagonalization of the transfer matrix projected onto irreducible\nrepresentations of the octahedral group for small to moderate size lattices,\nproviding an independent check of our few-body simulation results. We compare\nour exact numerical and simulation results for the spectrum to benchmark\nstudies of other research groups, as well as perform an extended analysis of\nour lattice action improvement scheme, including an analysis of the errors\nassociated with higher partial waves and finite temporal discretization.",
        "positive": "Effective meson-meson interaction in 2+1 dimensional lattice QED: A definition of an effective meson-meson interaction adapted to the framework\nof a lattice simulation is presented. Results, based on a truncated\nmomentum-space 4-point time correlation matrix, and preliminary data from a\ncomplementary coordinate-space simulation, are shown."
    },
    {
        "anchor": "Sign Problems in Quantum Field Theory: Classical and Quantum Approaches: Monte Carlo calculations in the framework of lattice field theory provide\nnon-perturbative access to the equilibrium physics of quantum fields. When\napplied to certain fermionic systems, or to the calculation of\nout-of-equilibrium physics, these methods encounter the so-called sign problem,\nand computational resource requirements become impractically large. These\ndifficulties prevent the calculation from first principles of the equation of\nstate of quantum chromodynamics, as well as the computation of transport\ncoefficients in quantum field theories, among other things.\n  This thesis details two methods for mitigating or avoiding the sign problem.\nFirst, via the complexification of the field variables and the application of\nCauchy's integral theorem, the difficulty of the sign problem can be changed.\nThis requires searching for a suitable contour of integration. Several methods\nof finding such a contour are discussed, as well as the procedure for\nintegrating on it. Two notable examples are highlighted: in one case, a contour\nexists which entirely removes the sign problem, and in another, there is\nprovably no contour available to improve the sign problem by more than a\n(parametrically) small amount.\n  As an alternative, physical simulations can be performed with the aid of a\nquantum computer. The formal elements underlying a quantum computation - that\nis, a Hilbert space, unitary operators acting on it, and Hermitian observables\nto be measured - can be matched to those of a quantum field theory. In this way\nan error-corrected quantum computer may be made to serve as a well controlled\nlaboratory. Precise algorithms for this task are presented, specifically in the\ncontext of quantum chromodynamics.",
        "positive": "Flavour singlet physics in lattice QCD with background fields: We show that hadronic matrix elements can be extracted from lattice\nsimulations with background fields that arise from operator exponentiation.\nImportantly, flavour-singlet matrix elements can be evaluated without requiring\nthe computation of disconnected diagrams, thus facilitating a calculation of\nthe quark contribution to the spin of the proton and the singlet axial\ncoupling, $g_A^0$. In the two nucleon sector, a background field approach will\nallow calculation of the magnetic and quadrupole moments of the deuteron and an\ninvestigation of the EMC effect directly from lattice QCD. Matrix elements\nbetween states of differing momenta are also analysed in the presence of\nbackground fields."
    },
    {
        "anchor": "Quenched Chiral Logs, the $\u03b7'$ Mass, and the Hairpin Diagram: Limits on the size of quenched chiral logs in the pion mass for Wilson\nfermions are investigated. The smallness of chiral logs is shown to be a result\nof the suppression of the hairpin diagram for small $p^2$, such that the value\nof the hairpin on the pion mass shell is much smaller than the physical\n$m_{\\eta'}^2$. A direct calculation of the topological susceptibility from the\nsame data gives $m_{\\eta'}\\approx 1$ GeV.",
        "positive": "Neutral $B$ meson mixings and $B$ meson decay constants with static\n  heavy and domain-wall light quarks: Neutral $B$ meson mixing matrix elements and $B$ meson decay constants are\ncalculated. Static approximation is used for $b$ quark and domain-wall fermion\nformalism is employed for light quarks. The calculations are carried out on\n$2+1$ flavor dynamical ensembles generated by RBC/UKQCD Collaborations with\nlattice spacings $0.086$fm ($a^{-1}\\sim 2.3$GeV) and $0.11$fm ($1.7$GeV), and a\nfixed physical spatial volume of about $(2.7{\\rm fm})^3$. In the static quark\naction, link-smearings are used to improve the signal-to-noise ratio. We employ\ntwo kinds of link-smearings, HYP1 and HYP2, and their results are combined in\ntaking the continuum limit. For the matching between the lattice and the\ncontinuum theory, one-loop perturbative $O(a)$ improvements are made to reduce\ndiscretization errors. As the most important quantity of this work, we obtain\nSU(3) breaking ratio $\\xi=1.208(60)$, where the error includes statistical and\nsystematic one. (Uncertainty from infinite $b$ quark mass is not included.) We\nalso find other neutral $B$ meson mixing quantities\n$f_B\\sqrt{\\hat{B}_B}=240(22)$MeV, $f_{B_s}\\sqrt{\\hat{B}_{B_s}}=290(22)$MeV,\n$\\hat{B}_B=1.17(22)$, $\\hat{B}_{B_s}=1.22(13)$ and $B_{B_s}/B_B=1.028(74)$, $B$\nmeson decay constants $f_B=219(17)$MeV, $f_{B_s}=264(19)$MeV and\n$f_{B_s}/f_B=1.193(41)$, in the static limit of $b$ quark, which do not include\ninfinite $b$ quark mass uncertainty."
    },
    {
        "anchor": "COMBINING MCRG AND FOURIER ACCELERATED LANGEVIN ALGORITHM: We study the implementation of Monte Carlo renormalization group (MCRG) in\nmomentum space. This technique is most efficient when used in combination with\na Fourier accelerated Langevin algorithm. As a benchmark we calculate the\ncritical exponents $\\nu$ and $\\eta$ in the vicinity of both the gaussian and\nthe Wilson fixed point in $\\lambda \\phi^4_3$. The results are very competitive\nwith alternative analytical methods and require a moderate computational effort\nonly.",
        "positive": "Applying polynomial filtering to mass preconditioned Hybrid Monte Carlo: The use of mass preconditioning or Hasenbusch filtering in modern Hybrid\nMonte Carlo simulations is common. At light quark masses, multiple filters\n(three or more) are typically used to reduce the cost of generating dynamical\ngauge fields; however, the task of tuning a large number of Hasenbusch mass\nterms is non-trivial. The use of short polynomial approximations to the inverse\nhas been shown to provide an effective UV filter for HMC simulations. In this\nwork we investigate the application of polynomial filtering to the mass\npreconditioned Hybrid Monte Carlo algorithm as a means of introducing many time\nscales into the molecular dynamics integration with a simplified parameter\ntuning process. A generalized multi-scale integration scheme that permits\narbitrary step- sizes and can be applied to Omelyan-style integrators is also\nintroduced. We find that polynomial-filtered mass-preconditioning (PF-MP)\nperforms as well as or better than standard mass preconditioning, with\nsignificantly less fine tuning required."
    },
    {
        "anchor": "Gauge invariance in a Z_2 hamiltonian lattice gauge theory: We propose an efficient variational method for $Z_2$ lattice gauge theory\nbased on the matrix product ansatz. The method is applied to ladder and square\nlattices. The Gauss law needs to be imposed on quantum states to guarantee\ngauge invariance when one studies gauge theory in hamiltonian formalism. On the\nladder lattice, we identify gauge invariant low-lying states by evaluating\nexpectation values of the Gauss law operator after numerical diagonalization of\nthe gauge hamiltonian. On the square lattice, the second order phase transition\nis well reproduced.",
        "positive": "Precision Upsilon Spectroscopy from Nonrelativistic Lattice QCD: The spectrum of the Upsilon system is investigated using the Nonrelativistic\nLattice QCD approach to heavy quarks and ignoring light quark vacuum\npolarization. We find good agreement with experiment for the Upsilon(1S),\nUpsilon(2S), Upsilon(3S) and for the center of mass and fine structure of the\nchi_b states. The lattice calculations predict b-bbar D-states with center of\nmass at (10.20 +/- 0.07 +/- 0.03)GeV. Fitting procedures aimed at extracting\nboth ground and excited state energies are developed. We calculate a\nnonperturbative dispersion mass for the Upsilon(1S) and compare with\ntadpole-improved lattice perturbation theory."
    },
    {
        "anchor": "Non-perturbative definition of the QCD energy-momentum tensor on the\n  lattice: We present a strategy to define non-perturbatively the energy-momentum tensor\nin Quantum Chromodynamics (QCD) which satisfies the appropriate Ward identities\nand has the right trace anomaly. The tensor is defined by regularizing the\ntheory on a lattice, and by fixing its renormalization constants\nnon-perturbatively by suitable Ward identities associated to the Poincare'\ninvariance of the continuum theory. The latter are derived in thermal QCD with\na non-zero imaginary chemical potential formulated in a moving reference frame.\nA renormalization group analysis leads to simple\nrenormalization-group-invariant definitions of the gluonic and fermionic\ncontributions to either the singlet or the non-singlet components of the\ntensor, and therefore of their form factors among physical states. The lattice\ndiscussion focuses on the Wilson discretization of quark fields but the\nstrategy is general. Specific to that case, we also carry out the analysis for\nthe on-shell O(a)-improvement of the energy-momentum tensor. The\nrenormalization and improvement programs profit from the fact that, as shown\nhere, the thermal theory enjoys de-facto automatic O(a)-improvement at finite\ntemperature. The validity of the proposal is scrutinized analytically by a\nstudy to 1-loop order in lattice perturbation theory with shifted and twisted\n(for quarks only) boundary conditions. The latter provides also additional\nuseful insight for a precise non-perturbative calculation of the\nrenormalization constants. The strategy proposed here is accessible to Monte\nCarlo computations, and in this sense it provides a practical way to define\nnon-perturbatively the energy-momentum tensor in QCD.",
        "positive": "Tests of Electric Polarizability on the Lattice: Using clover fermions on CP-PACS dynamical configurations, we consider a\nnumber of ways of measuring hadronic electric polarizability, an\n$|\\mathbf{E}|^{2}$ effect in hadron masses, using lattice techniques. We\nconsider the effects of periodic and Dirichlet boundary conditions, the field\nlinearization postulate as well as a quantized electric field. We also consider\ntwo ways of formulating the classical vector potential which describes a\nuniform electric field in combination with the other possibilities."
    },
    {
        "anchor": "Monopole Condensation and Confinement in SU(2) QCD (2): Monopole and photon contributions to Wilson loops are calculated using\nMonte-Carlo simulations of SU(2) QCD in the maximally abelian gauge. The string\ntensions of SU(2) QCD are well reproduced by extended monopole contributions\nalone.",
        "positive": "Physics results from dynamical overlap fermion simulations: I summarize the physics results obtained from large-scale dynamical overlap\nfermion simulations by the JLQCD and TWQCD collaborations. The numerical\nsimulations are performed at a fixed global topological sector; the physics\nresults in the theta-vacuum is reconstructed by correcting the finite volume\neffect, for which the measurement of the topological susceptibility is crucial.\nPhysics applications we studied so far include a calculation of chiral\ncondensate, pion mass, decay constant, form factors, as well as (vector and\naxial-vector) vacuum polarization functions and nucleon sigma term."
    },
    {
        "anchor": "The spatial string tension from the Field Correlator Method: The phenomenon of the almost linear growth of the square root of spatial\nstring tension $\\sqrt{\\sigma_s(T)}= c_{\\sigma} g^2 T$ was found both in lattice\nand in theory, based on the Field Correlator Method (FCM). In the latter the\nstring tension (both spatial and colorelectric) is expressed as an integral of\nthe two gluon Green's function calculated with the same string tension:\n$\\sigma= \\int G^{(2g)}_{\\sigma}$. This relation allows to check the\nselfconsistency of the theory. However at nonzero temperature $T$ in the\ntwo-gluon Green's function in the space-like region appear terms which create\nin $\\sigma_s$ quadratic in T behavior. We calculate below in the paper the\n$\\sigma_s$ numerically in the whole temperature region $T_c< T < 5 T_c$ using\nthe FCM method and compare the results with lattice data finding a good\nagreement. This justifies the use of the FCM in the space-like region and in\nhigh T thermodynamics without extra parameters.",
        "positive": "Improving the Lattice QED Action: Strongly coupled QED is a model whose physics is dominated by short-ranged\neffects. In order to assess which features of numerical simulations of the\nchiral phase transition are universal and which are not, we have formulated a\nquenched version of the model in which photon degrees of freedom are defined on\na lattice of spacing a, but fermions only on a lattice of spacing 2a. The\nfermi-photon interaction is then obtained via a blocking procedure, whose\nparameters allow a degree of control over the relative importance of short\nwavelength modes. Results from a variety of models are presented; the critical\nexponents delta and beta governing the transition appear to be independent of\nthe blocking, or even of whether a gauge-invariant action is used for the\nphotons."
    },
    {
        "anchor": "Scaling and low energy constants in lattice QCD with N_f=2 maximally\n  twisted Wilson quarks: We report on the scaling of basic hadronic observables in lattice QCD with\nN_f=2 maximally twisted Wilson dynamical quarks. We give preliminary results\nfor some of the Gasser-Leutwyler low energy constants, the chiral condensate\nand the average mass of u and d quarks.",
        "positive": "The Upsilon Spectrum from Lattice QCD with 2+1 Flavors of Dynamical\n  Quarks: We describe the bottomonium spectrum obtained on the MILC configurations\nwhich incorporate 2+1 flavors of dynamical quarks. We compare to quenched and 2\nflavor results also on MILC configurations. We show that the lattice spacing\ndetermination using different quantities shows clear signs of convergence with\n2+1 flavors and give results for the leptonic width and hyperfine splitting, in\nthe form of the ratio of the 1st excited state of the Upsilon to that of the\nground state."
    },
    {
        "anchor": "Chiral Symmetry Breaking and Cooling in Lattice QCD: Chiral symmetry breaking is calculated as a function of cooling in quenched\nlattice QCD. A non-zero signal is found for the chiral condensate beyond one\nhundred cooling steps, suggesting that there is chiral symmetry breaking\nassociated with instantons. Quantitatively, the chiral condensate in cooled\ngauge field configurations is small compared to the value without cooling.",
        "positive": "Understanding CP violation in lattice QCD: It is pointed out that any CP violation which may be found in lattice QCD\nwith a chiral phase in the fermion mass term cannot be relevant for the\ncontinuum theory. CP is classically conserved in the corresponding continuum\ntheory and is non-anomalous."
    },
    {
        "anchor": "Chiral Limit of Nucleon Lattice Electromagnetic Form Factors: We calculate electric and magnetic form factors of protons and neutrons in\nquenched Monte Carlo lattice QCD on a $16^3\\times 24$ lattice at $\\beta = 6.0$\nusing Wilson fermions. We employ a method which characterizes one of the\nnucleon fields as a fixed zero-momentum secondary source. Extrapolating the\noverall data set to the chiral limit, we find acceptable fits for either dipole\nor monopole forms and extract proton and neutron magnetic moments, the\nmagnitude of which are $10$ to $15\\%$ low compared to experiment. In the\nextrapolation of the dipole fit of the form factors, we find that the dipole to\nnucleon mass ratio is about $7\\%$ low compared to experiment. In addition, we\nobtain positive values of the neutron electric form factor, which, however, are\npoorly represented by a popular phenomenological form at intermediate to small\n$\\kappa$ values. A zero-momentum technique for extracting hadron magnetic\nmoments is briefly discussed and shown to yield unrealistically small magnetic\nmoment values.",
        "positive": "Two Particle States and the $S$-matrix Elements in Multi-channel\n  Scattering: Using a quantum mechanical model, the exact energy eigenstates for\ntwo-particle two-channel scattering are studied in a cubic box with periodic\nboundary conditions in all three directions. A relation between the exact\nenergy eigenvalue in the box and the two-channel $S$-matrix elements in the\ncontinuum is obtained. This result can be viewed as a generalization of the\nwell-known L\\\"uscher's formula which establishes a similar relation in elastic\nscattering."
    },
    {
        "anchor": "Exploring conformality in lattice N=4 supersymmetric Yang--Mills: Maximally supersymmetric Yang--Mills theory (N=4 SYM) is conformal for any\nvalue of the coupling. Lattice regularization breaks conformality through the\nintroduction of a non-zero lattice spacing and a finite lattice volume. This\nproceedings presents ongoing numerical computations of conformal scaling\ndimensions in lattice N=4 SYM, based on a lattice formulation that exactly\npreserves a supersymmetry sub-algebra at non-zero lattice spacing. The main\ntargets are the non-trivial anomalous dimension of the Konishi operator, as\nwell as a mass anomalous dimension extracted from the eigenvalue mode number of\nthe fermion operator. The latter is expected to vanish in the conformal\ncontinuum theory, providing insight into the interplay of lattice\ndiscretization and conformality.",
        "positive": "Pionic couplings (g^ and g~) in the static heavy quark limit: The couplings between the soft pion and the doublet of heavy-light mesons are\nbasic parameters of the ChPT approach to the heavy-light systems. We compute\nthe unquenched (Nf=2) values of two such couplings in the static heavy quark\nlimit: (1) g^, coupling to the lowest doublet of heavy-light mesons, and (2)\ng~, coupling to the first orbital excitations. A brief description of the\ncalculation together with a short discussion of the results is presented."
    },
    {
        "anchor": "Analytical derivation of gauge fields from link variables in SU(3)\n  lattice QCD and its application in maximally Abelian gauge: In SU(3) lattice QCD, we improve a method to extract gauge fields from link\nvariables analytically. With this method, we perform the first study on the\neffective mass generation of off-diagonal gluons and infrared Abelian dominance\nin the maximally Abelian (MA) gauge in the SU(3) case. We investigate the\npropagator and the effective mass of the off-diagonal gluon field in the MA\ngauge with ${\\rm U(1)}_3 \\times {\\rm U(1)}_8$ Landau gauge fixing in SU(3)\nquenched lattice QCD on $16^4$ at $\\beta$=5.7, 5.8 and 6.0. The off-diagonal\ngluon component behaves as a massive vector boson with the approximate\neffective mass $M_{\\rm off} = 1.1 - 1.2 {\\rm GeV}$ in the region of $r = 0.3 -\n0.8 {\\rm fm}$, and its propagation is limited within a short range. We thus\nshow the origin of infrared Abelian dominance in terms of short-range\npropagation of off-diagonal gluons. We also investigate the functional form of\nthe off-diagonal gluon propagator. We find that the functional form is well\ndescribed by the four-dimensional Euclidean Yukawa-type function ${\\rm\nexp}\\{-m_{\\rm off} r\\}/r$ with $m_{\\rm off} = 1.3 -1.4 {\\rm GeV}$ for $r = 0.1-\n0.8{\\rm fm}$. This also indicates that the spectral function has a negative\nregion.",
        "positive": "Dynamical fat link fermions: The use of APE smearing or other blocking techniques in fermion actions can\nprovide many advantages. There are many variants of these fat link actions in\nlattice QCD currently, such as FLIC fermions. Frequently, fat link actions make\nuse of the APE blocking technique in combination with a projection of the\nblocked links back into the special unitary group. This reunitarisation is\noften performed using an iterative maximisation of a gauge invariant measure.\nThis technique is not differentiable with respect to the gauge field and thus\nprevents the use of standard Hybrid Monte Carlo simulation algorithms. The use\nof an alternative projection technique circumvents this difficulty and allows\nthe simulation of dynamical fat link fermions with standard HMC and its\nvariants."
    },
    {
        "anchor": "Anomaly and a QCD-like phase diagram with massive bosonic baryons: We study a strongly coupled $Z_2$ lattice gauge theory with two flavors of\nquarks, invariant under an exact $\\mathrm{SU}(2)\\times \\mathrm{SU}(2) \\times\n\\mathrm{U}_A(1) \\times \\mathrm{U}_B(1)$ symmetry which is the same as QCD with\ntwo flavors of quarks without an anomaly. The model also contains a coupling\nthat can be used to break the $\\mathrm{U}_A(1)$ symmetry and thus mimic the QCD\nanomaly. At low temperatures $T$ and small baryon chemical potential $\\mu_B$\nthe model contains massless pions and massive bosonic baryons similar to QCD\nwith an even number of colors. In this work we study the $T-\\mu_B$ phase\ndiagram of the model and show that it contains three phases : (1) A chirally\nbroken phase at low $T$ and $\\mu_B$, (2) a chirally symmetric baryon superfluid\nphase at low $T$ and high $\\mu_B$, and (3) a symmetric phase at high $T$. We\nfind that the nature of the finite temperature chiral phase transition and in\nparticular the location of the tricritical point that seperates the first order\nline from the second order line is affected significantly by the anomaly.",
        "positive": "Scalar and vector form factors of $D \\to \u03c0(K) \\ell \u03bd$ decays with\n  $N_f=2+1+1$ twisted fermions: We present a lattice determination of the vector and scalar form factors of\nthe $D \\to \\pi(K) \\ell \\nu$ semileptonic decays, which are relevant for the\nextraction of the CKM matrix elements $|V_{cd}|$ and $|V_{cs}|$ from\nexperimental data. Our analysis is based on the gauge configurations produced\nby the European Twisted Mass Collaboration with $N_f = 2+1+1$ flavors of\ndynamical quarks, at three different values of the lattice spacing and with\npion masses as small as 210 MeV. The matrix elements of both vector and scalar\ncurrents are determined for a plenty of kinematical conditions in which parent\nand child mesons are either moving or at rest. Lorentz symmetry breaking due to\nhypercubic effects is clearly observed in the data and included in the\ndecomposition of the current matrix elements in terms of additional form\nfactors. After the extrapolations to the physical pion mass and to the\ncontinuum limit we determine the vector and scalar form factors in the whole\nkinematical region from $q^2 = 0$ up to $q^2_{max} = (M_D - M_{\\pi(K)})^2$\naccessible in the experiments, obtaining a good overall agreement with\nexperiments, except in the region at high values of $q^2$ where some deviations\nare visible. A set of synthetic data points, representing our results for\n$f_+^{D \\pi(K)}(q^2)$ and $f_0^{D \\pi(K)}(q^2)$ for several selected values of\n$q^2$, is provided and also the corresponding covariance matrix is available.\nAt zero 4-momentum transfer we get: $f_+^{D \\to \\pi}(0) = 0.612 ~ (35)$ and\n$f_+^{D \\to K}(0) = 0.765 ~ (31)$. Using the experimental averages for\n$|V_{cd}| f_+^{D \\to \\pi}(0)$ and $|V_{cs}| f_+^{D \\to K}(0)$, we extract\n$|V_{cd}| = 0.2330 ~ (137)$ and $|V_{cs}| = 0.945 ~ (38)$, respectively. The\nsecond-row of the CKM matrix is found to be in agreement with unitarity within\nthe current uncertainties: $|V_{cd}|^2 + |V_{cs}|^2 + |V_{cb}|^2 = 0.949 ~\n(78)$."
    },
    {
        "anchor": "Effective Field Theory for the Anisotropic Wilson Lattice Action: We construct the effective field theory appropriate for describing the low\nenergy behavior of anisotropic Wilson lattice actions and the O(a) improved\nvariant thereof. We then apply this effective field theory to the hadron\nspectrum and dispersion relations, focussing on the corrections due to the\nanisotropy. We point out an important feature of anisotropic lattices regarding\nthe Aoki-regime; for a given set of fermion masses and spatial lattice spacing,\nif an isotropic action is in the QCD-phase, this does not guarantee that the\nanisotropic action is outside the Aoki-regime. This may be important in the\ntuning of bare parameters for anisotropic lattices using domain-wall and\noverlap fermions as well as Wilson and O(a)-improved Wilson fermions.",
        "positive": "$\u03a9_c \u03b3\\rightarrow\u03a9_c^\\ast$ transition in lattice QCD: We study the electromagnetic $\\Omega_c \\gamma \\rightarrow\\Omega_c^\\ast$\ntransition in 2+1 flavor lattice QCD, which gives access to the dominant decay\nmode of $\\Omega_c^\\ast$ baryon. The magnetic dipole and the electric quadrupole\ntransition form factors are computed. The magnetic dipole form factor is found\nto be mainly determined by the strange quark and the electric quadrupole form\nfactor to be negligibly small, in consistency with the quark model. We also\nevaluate the helicity amplitudes and the decay rate."
    },
    {
        "anchor": "Non-Exponential Relaxation Time Scales in Disordered Systems: an\n  Application to Protein Dynamics: We study the dynamics of an heteropolymeric chain relaxing toward a new\nequilibrium configuration after the action of an external perturbation. We\ncompare the results from Monte Carlo simulations with the results of a Langevin\nnormal mode decomposition. We discuss, for sake of comparison, the case of an\nordered homopolymeric chain.",
        "positive": "The (LATTICE) QCD Potential and Running Coupling: How to Accurately\n  Interpolate between Multi-Loop QCD and the String Picture: We present a simple parameterization of a running coupling constant, defined\nvia the static potential, that interpolates between 2-loop QCD in the UV and\nthe string prediction in the IR. Besides the usual $\\Lam$-parameter and the\nstring tension, the coupling depends on one dimensionless parameter,\ndetermining how fast the crossover from UV to IR behavior occurs (in principle\nwe know how to take into account any number of loops by adding more\nparameters). Using a new Ansatz for the LATTICE potential in terms of the\ncontinuum coupling, we can fit quenched and unquenched Monte Carlo results for\nthe potential down to ONE lattice spacing, and at the same time extract the\nrunning coupling to high precision. We compare our Ansatz with 1-loop results\nfor the lattice potential, and use the coupling from our fits to quantitatively\ncheck the accuracy of 2-loop evolution, compare with the Lepage-Mackenzie\nestimate of the coupling extracted from the plaquette, and determine Sommer's\nscale $r_0$ much more accurately than previously possible. For pure SU(3) we\nfind that the coupling scales on the percent level for $\\beta\\geq 6$."
    },
    {
        "anchor": "Chromoelectric flux tubes and coherence length in QCD: The transverse profile of the chromoelectric flux tubes in SU(2) and SU(3)\npure gauge theories is analyzed by a simple variational ansatz using a strict\nanalogy with ordinary superconductivity. Our method allows to extract the\npenetration length and the coherence length of the flux tube.",
        "positive": "Novel fat-link fermion actions: The hadron mass spectrum is calculated in lattice QCD using a novel fat-link\nclover fermion action in which only the irrelevant operators of the fermion\naction are constructed using smeared links. The simulations are performed on a\n16^3 X 32 lattice with a lattice spacing of a=0.125 fm. We compare actions with\nn=4 and 12 smearing sweeps with a smearing fraction of 0.7. The n=4 Fat Link\nIrrelevant Clover (FLIC) action provides scaling which is superior to\nmean-field improvement, and offers advantages over nonperturbative O(a)\nimprovement."
    },
    {
        "anchor": "Staggered Fermions and Gauge Field Topology: Based on a large number of smearing steps, we classify SU(3) gauge field\nconfigurations in different topological sectors. For each sector we compare the\nexact analytical predictions for the microscopic Dirac operator spectrum of\nquenched staggered fermions. In all sectors we find perfect agreement with the\npredictions for the sector of topological charge zero, showing explicitly that\nthe smallest Dirac operator eigenvalues of staggered fermions at presently\nrealistic lattice couplings are insensitive to gauge field topology. On the\nsmeared configurations, $4\\nu$ eigenvalues clearly separate out from the rest\non configurations of topological charge $\\nu$, and move towards zero in\nagreement with the index theorem.",
        "positive": "Ph.D. Thesis: Chiral Effective Field Theory Beyond the Power-Counting\n  Regime: Novel techniques are presented, which identify the power-counting regime\n(PCR) of chiral effective field theory, and allow the use of lattice quantum\nchromodynamics results that extend outside the PCR. By analyzing the\nrenormalization of low-energy coefficients of the chiral expansion of the\nnucleon mass, the existence of an optimal regularization scale is realized. The\ntechniques developed for the nucleon mass renormalization are then applied to a\ntest case: performing a chiral extrapolation without prior phenomenological\nbias. The robustness of the procedure for obtaining an optimal regularization\nscale and performing a reliable chiral extrapolation is confirmed. The\nprocedure developed is then applied to the magnetic moment and the electric\ncharge radius of the nucleon. The consistency of the results for the value of\nthe optimal regularization scale provides strong evidence for the existence of\nan intrinsic energy scale in the nucleon-pion interaction."
    },
    {
        "anchor": "The running quark mass in the SF scheme and its two-loop anomalous\n  dimension: The non-perturbatively defined running quark mass introduced by the ALPHA\ncollaboration is based on the PCAC relation between correlation functions\nderived from the Schr\\\"odinger functional (SF). In order to complete its\ndefinition it remains to specify a number of parameters, including the ratio of\ntime to spatial extent, $T/L$, and the angle $\\theta$ which appears in the\nspatial boundary conditions for the quark fields. We investigate the running\nmass in perturbation theory and propose a choice of parameters which attains\ntwo desired properties: firstly the two-loop anomalous dimension $\\d1SF$ is\nreasonably small. This is needed in order to ease matching with the\nnon-perturbative computations and to achieve a precise determination of the\nrenormalization group invariant quark mass. Secondly, to one-loop order of\nperturbation theory, cut-off effects in the step-scaling function are small in\nO($a$) improved lattice QCD.",
        "positive": "Using evolutionary algorithms to extract field theory mass spectra: The spectrum of masses from a lattice QCD simulation may be found by fitting\nexponential functions to correlators of operators possessing the quantum\nnumbers of the particles of interest. The ability of evolutionary algorithms to\nfind globally optimized solutions containing a variable number of states across\nmultiple data sets is exploited to provide a promising solution to the problem\nof finding these fits."
    },
    {
        "anchor": "Progress in four-dimensional lattice supersymmetry: We are entering an era where a number of large-scale lattice simulations of\nfour-dimensional supersymmetric theories are under way. Moreover, proposals for\nhow to approach such studies continue to progress. One particular line of\nresearch in this direction is described here. General actions for super-QCD,\nincluding counterterms required on the lattice, are given. We obtain the number\nof fine-tunings that is required, once gauge and flavor symmetries are\naccounted for, provided Ginsparg-Wilson fermions are used for the gauginos. We\nalso review and extend our recent work on lattice formulations of N=4\nsuper-Yang-Mills and N=1 super-Yang-Mills that exploit Ginsparg-Wilson\nfermions.",
        "positive": "Comparison of Multi-quark Matrix Inversion Algorithms: We test iterative algorithms, MR, QMR$\\gamma_5$ and BiCG$\\gamma_5$, to\ncompare their efficiency in matrix inversion with multi-quarks (shifted\nmatrices) within one iteration process. Our results on the 8^3 x 12 and 16^3 x\n24 show that MR admits multi-quark calculation with less memory requirement,\nwhereas QMR is faster for the single quark calculation."
    },
    {
        "anchor": "Improving the low-lying spectrum of the overlap kernel: The action of the overlap-Dirac operator on a vector is typically implemented\nin directly through a multi-shift conjugate gradient solver. The compute-time\nthis takes to evaluate depends upon the condition number $\\kappa$ of the matrix\nthat is used as the overlap kernel. We examine the low-lying spectra of various\ncandidate kernels in an effort to optimise $\\kappa$, thereby speeding up the\noverlap evaluation.",
        "positive": "Bayesian approach to the first excited nucleon state in lattice QCD: We present preliminary results from the first attempt to reconstruct the\nspectral function in the nucleon and $\\Delta$ channels from lattice QCD data\nusing the maximum entropy method (MEM). An advantage of the MEM analysis is to\nenable us to access information of the excited state spectrum. Performing\nsimulations on two lattice volumes, we confirm the large finite size effect on\nthe first excited nucleon state in the lighter quark mass region."
    },
    {
        "anchor": "Instanton Content of the SU(3) Vacuum: We study the topological content of the SU(3) vacuum using the\nrenormalization group (RG) mapping method. RG mapping is a simple smoothing\nalgorithm, in which a series of APE-smearing steps are done while the\ntopological content of the configuration is carefully monitored. This\nmonitoring process makes it possible to separate true topological objects from\nvacuum fluctuations and allows an extrapolation to zero smearing steps. Using\nRG mapping we have measured the instanton distribution and topological\nsusceptibility for SU(3) gauge theory. We arrive at a value for the topological\nsusceptibily, ${\\chi}^{1/4}$ of 203(5) MeV. The size distribution peaks at\n$\\rho=0.3$fm, and is in good agreement with the prediction of instanton liquid\nmodels.",
        "positive": "On the spectral density from instantons in quenched QCD: We investigate the contribution of instantons to the eigenvalue spectrum of\nthe Dirac operator in quenched QCD. The instanton configurations that we use\nhave been derived, elsewhere, from cooled SU(3) lattice gauge fields and, for\ncomparison, we also analyse a random `gas' of instantons. Using a set of\nsimplifying approximations, we find a non-zero chiral condensate. However we\nalso find that the spectral density diverges for small eigenvalues, so that the\nchiral condensate, at zero quark mass, diverges in quenched QCD. The degree of\ndivergence decreases with the instanton density, so that it is negligible for\nthe smallest number of cooling sweeps but becomes substantial for larger number\nof cools. We show that the spectral density scales, that finite volume\ncorrections are small and we see evidence for the screening of topological\ncharges. However we also find that the spectral density and chiral condensate\nvary rapidly with the number of cooling sweeps -- unlike, for example, the\ntopological susceptibility. Whether the problem lies with the cooling or with\nthe identification of the topological charges is an open question. This problem\nneeds to be resolved before one can determine how important is the divergence\nwe have found for quenched QCD."
    },
    {
        "anchor": "Nucleon, $\u0394$ and $\u03a9$ excited states in $N_f=2+1$ lattice QCD: The energies of the excited states of the Nucleon, $\\Delta$ and $\\Omega$ are\ncomputed in lattice QCD, using two light quarks and one strange quark on\nanisotropic lattices. The calculation is performed at three values of the light\nquark mass, corresponding to pion masses $m_{\\pi}$ = 392(4), 438(3) and 521(3)\nMeV. We employ the variational method with a large basis of interpolating\noperators enabling six energies in each irreducible representation of the\nlattice to be distinguished clearly. We compare our calculation with the\nlow-lying experimental spectrum, with which we find reasonable agreement in the\npattern of states. The need to include operators that couple to the expected\nmulti-hadron states in the spectrum is clearly identified.",
        "positive": "Nematic Confined Phases in the $U(1)$ Quantum Link Model on a Triangular\n  Lattice: An Opportunity for Near-Term Quantum Computations of String Dynamics\n  on a Chip: The $U(1)$ quantum link model on the triangular lattice has two\nrotation-symmetry-breaking nematic confined phases. Static external charges are\nconnected by confining strings consisting of individual strands with\nfractionalized electric flux. The two phases are separated by a weak first\norder phase transition with an emergent almost exact $SO(2)$ symmetry. We\nconstruct a quantum circuit on a chip to facilitate near-term quantum\ncomputations of the non-trivial string dynamics."
    },
    {
        "anchor": "Gross-Neveu model as a laboratory for fermion discretization: We introduce a finite volume renormalization scheme for the\nN-Majorana-component O(N) invariant Gross-Neveu model. Universal observables\nare defined that are accessible to precise numerical simulation in various\ndiscretizations and allow for an extrapolation to the continuum limit. Here\nfirst numerical results with Wilson fermions are reported. For N=2 they\nreproduce exact finite volume continuum results in the massless Thirring model.\nOur N=8 data are ready for comparison for instance with staggered results in\nthe future.",
        "positive": "Net-baryon number fluctuations: The appearance of large, none-Gaussian cumulants of the baryon number\ndistribution is commonly discussed as a signal for the QCD critical point. We\nreview the status of the Taylor expansion of cumulant ratios of baryon number\nfluctuations along the freeze-out line and also compare QCD results with the\ncorresponding proton number fluctuations as measured by the STAR Collaboration\nat RHIC. To further constrain the location of a possible QCD critical point we\ndiscuss poles of the baryon number fluctuations in the complex plane. Here we\nuse not only the Taylor coefficients obtained at zero chemical potential but\nperform also calculations of Taylor expansion coefficients of the pressure at\npurely imaginary chemical potentials."
    },
    {
        "anchor": "Determination of Vub from B->pi l nu on the lattice: We present results of a lattice study of the form factors in the decay B-> pi\nl nu. We attempt to disentangle the the dependence of the form factors on the\nlight quark masses and the momentum transfer. Using models of the q^2\ndependence we calculate the total decay rate, and compare to the experimental\nmeasure to extract Vub. This study was performed in the quenched approximation\nat beta=6.2 on a 24^3 X 48 lattice, with a non-perturbatively improved SW\nfermion action.",
        "positive": "Determination of the $\u0394S = 1$ weak Hamiltonian in the SU(4) chiral\n  limit through topological zero-mode wave functions: A new method to determine the low-energy couplings of the $\\Delta S=1$ weak\nHamiltonian is presented. It relies on a matching of the topological poles in\n$1/m^2$ of three-point correlators of two pseudoscalar densities and a\nfour-fermion operator, measured in lattice QCD, to the same observables\ncomputed in the $\\epsilon$-regime of chiral perturbation theory. We test this\nmethod in a theory with a light charm quark, i.e. with an SU(4) flavour\nsymmetry. Quenched numerical measurements are performed in a 2 fm box, and\nchiral perturbation theory predictions are worked out up to next-to-leading\norder. The matching of the two sides allows to determine the weak low-energy\ncouplings in the SU(4) limit. We compare the results with a previous\ndetermination, based on three-point correlators containing two left-handed\ncurrents, and discuss the merits and drawbacks of the two procedures."
    },
    {
        "anchor": "Non-perturbative renormalization of the static axial current in\n  two-flavour QCD: We perform the non-perturbative renormalization of matrix elements of the\nstatic-light axial current by a computation of its scale dependence in lattice\nQCD with two flavours of massless O(a) improved Wilson quarks. The\nregularization independent factor that relates any running renormalized matrix\nelement of the axial current in the static effective theory to the\nrenormalization group invariant one is evaluated in the Schroedinger functional\nscheme, where in this case we find a significant deviation of the\nnon-perturbative running from the perturbative prediction. An important\ntechnical ingredient to improve the precision of the results consists in the\nuse of modified discretizations of the static quark action introduced earlier\nby our collaboration. As an illustration how to apply the renormalization of\nthe static axial current presented here, we connect the bare matrix element of\nthe current to the B_s-meson decay constant in the static approximation for one\nvalue of the lattice spacing, a ~ 0.08 fm, employing large-volume N_f=2 data at\nbeta=5.3.",
        "positive": "Moments of nucleon isovector structure functions in $2+1+1$-flavor QCD: We present results on the isovector momentum fraction, $\\langle x\n\\rangle_{u-d}$, helicity moment, $\\langle x \\rangle_{\\Delta u-\\Delta d}$, and\nthe transversity moment, $\\langle x \\rangle_{\\delta u-\\delta d}$, of the\nnucleon obtained using nine ensembles of gauge configurations generated by the\nMILC collaboration using $2+1+1$-flavors of dynamical highly improved staggered\nquarks (HISQ). The correlation functions are calculated using the Wilson-Clover\naction and the renormalization of the three operators is carried out\nnonperturbatively on the lattice in the RI${}^\\prime$-MOM scheme. The data have\nbeen collected at lattice spacings $a \\approx 0.15,\\ 0.12,\\ 0.09,$ and 0.06 fm\nand $M_\\pi \\approx 310,\\ 220$ and 135 MeV, which are used to obtain the\nphysical values using a simultaneous chiral-continuum-finite-volume fit. The\nfinal results, in the $\\overline{MS}$ scheme at 2 GeV, are $\\langle x\n\\rangle_{u-d} = 0.173(14)(07)$, $\\langle x \\rangle_{\\Delta u-\\Delta d} =\n0.213(15)(22)$ and $\\langle x \\rangle_{\\delta u-\\delta d} = 0.208(19)(24)$,\nwhere the first error is the overall analysis uncertainty and the second is an\nadditional systematic uncertainty due to possible residual excited-state\ncontributions. These results are consistent with other recent lattice\ncalculations and phenomenological global fit values."
    },
    {
        "anchor": "A Gauge-Independent Mechanism for Confinement and Mass Gap: Part II --\n  G=SU(2) and D=3: We apply to the case of gauge group G = SU(2) in three dimensions a recently\nproposed gauge-independent mechanism for confinement that is based on a\nparticular form of the dual spin foam framework for lattice gauge theory.\nExplicit formulae for interaction factors and their asymptotics are introduced\nand their behavior in different sectors of the theory are identified and\nanalyzed. We arrive at several elementary properties of the dual theory that\nrepresent one scenario by which confinement may be realized at weak coupling.\nWe conclude with an outlook for further development of this approach.",
        "positive": "Complex saddle points and the sign problem in complex Langevin\n  simulation: We show that complex Langevin simulation converges to a wrong result, by\nrelating it to the Lefschetz-thimble path integral, when the path-integral\nweight has different phases among dominant complex saddle points. Equilibrium\nsolution of the complex Langevin equation forms local distributions around\ncomplex saddle points. Its ensemble average approximately becomes a direct sum\nof the average in each local distribution, where relative phases among them are\ndropped. We propose that by taking these phases into account through\nreweighting, we can solve the wrong convergence problem. However, this\nprescription may lead to a recurrence of the sign problem in the complex\nLangevin method for quantum many-body systems."
    },
    {
        "anchor": "About Monopoles in QCD: The hypothesis is analysed that the monopoles condensing in QCD vacuum to\nmake it a dual superconductor are classical solutions of the equations of\nmotion.",
        "positive": "Critical properties of the Antiferromagnetic \\RP2$ model in three\n  dimensions: We study the behavior of the antiferromagnetic RP$^2$ model in $d=3$. The\nvacuum structure is analyzed in the critical and low temperature regions,\npaying special attention to the spontaneous symmetry breaking pattern. Near the\ncritical point we observe a full breakdown of the O(3) symmetry of the action.\nSeveral methods for computing critical exponents are compared. We conclude that\nthe most solid determination is obtained using a measure of the correlation\nlength. Corrections-to-scaling are parameterized, yielding a very accurate\ndetermination of the critical coupling and a 5\\% error measure of the related\nexponent. This is used to estimate the systematic errors due to finite-size\neffects."
    },
    {
        "anchor": "N=1 supersymmetric Yang-Mills theory on the lattice: Numerical simulations of supersymmetric theories on the lattice are intricate\nand challenging with respect to their theoretical foundations and algorithmic\nrealisation. Nevertheless, the simulations of a four-dimensional supersymmetric\ngauge theory have made considerable improvements over the recent years. In this\ncontribution we summarise the results of our collaboration concerning the mass\nspectrum of this theory. The investigation of systematic errors allows now a\nmore precise estimate concerning the expected formation of supersymmetric\nmultiplets of the lightest particles. These multiplets contain flavour singlet\nmesons, glueballs, and an additional fermionic state.",
        "positive": "Spectral functions and dynamic critical behavior of relativistic $Z_2$\n  theories: We investigate the dynamic critical behaviour of a relativistic scalar field\ntheory with $Z_2$ symmetry by calculating spectral functions of the order\nparameter at zero and non-vanishing momenta from first-principles\nclassical-statistical lattice simulations in real-time. We find that at\ntemperatures above the critical point $(T > T_c)$, the spectral functions are\nwell described by relativistic quasi-particle peaks. Close to the transition\ntemperature $(T \\sim T_c)$, we observe strong infrared contributions building\nup. In the ordered phase at low temperatures $(T < T_c)$, in addition to the\nquasi-particle peak, we observe a soft mode with a dispersion relation\nindicative of collective excitations. Investigating the spectral functions\nclose to $T_c$, we demonstrate that the behavior in the vicinity of the\ncritical point is controlled by dynamic scaling functions and the dynamic\ncritical exponent $z$, which we determine from our simulations. By considering\nthe equations of motion for a closed system and a system coupled to a heat\nbath, we extract the dynamic critical behavior for two different dynamic\nuniversality classes (Models A & C) in two and three spatial dimensions."
    },
    {
        "anchor": "Improved interpolating fields for hadrons at non-vanishing momentum: We demonstrate that a reduction in the noise-to-signal ratio may be obtained\nfor hadrons at non-zero momenta whilst maintaining a good overlap with the\nground state through a generalisation of Gaussian/Wuppertal smearing. The use\nof an anisotropic smearing wavefunction is motivated by the physical picture of\na boosted hadron.",
        "positive": "K0-K0bar Mixing with Wilson Fermions without Subtractions: By using suitable Ward identities, we show that it is possible to compute\nK0-K0bar mixing without subtracting the terms generated by explicit chiral\nsymmetry breaking present in Wilson-like lattice actions. The accuracy in the\ndetermination of the amplitudes is of O(a), which is the best one attainable in\nthe absence of improvement."
    },
    {
        "anchor": "Accelerating QDP++ using GPUs: Graphic Processing Units (GPUs) are getting increasingly important as target\narchitectures in scientific High Performance Computing (HPC). NVIDIA\nestablished CUDA as a parallel computing architecture controlling and making\nuse of the compute power of GPUs. CUDA provides sufficient support for C++\nlanguage elements to enable the Expression Template (ET) technique in the\ndevice memory domain. QDP++ is a C++ vector class library suited for quantum\nfield theory which provides vector data types and expressions and forms the\nbasis of the lattice QCD software suite Chroma. In this work accelerating QDP++\nexpression evaluation to a GPU was successfully implemented leveraging the ET\ntechnique and using Just-In-Time (JIT) compilation. The Portable Expression\nTemplate Engine (PETE) and the C API for CUDA kernel arguments were used to\nbuild the bridge between host and device memory domains. This provides the\npossibility to accelerate Chroma routines to a GPU which are typically not\nsubject to special optimisation. As an application example a smearing routine\nwas accelerated to execute on a GPU. A significant speed-up compared to normal\nCPU execution could be measured.",
        "positive": "Discretization effects in $N_c=2$ QCD and Random Matrix Theory: We summarize the analytical solution of the Chiral Perturbation Theory for\nthe Hermitian Wilson Dirac operator of $N_c=2$ QCD with quarks in the\nfundamental representation. Results have been obtained for the quenched\nmicroscopic spectral density, the distribution of the chiralities over the real\nmodes and the chiral condensate. The analytical results are compared with\nresults from a Monte Carlo simulation of the corresponding Random Matrix\nTheory."
    },
    {
        "anchor": "K -> pi vector form factor with N_f=2+1+1 Twisted Mass fermions: We present a lattice QCD determination of the vector form factor of the kaon\nsemileptonic decay K -> pi l nu which is relevant for the extraction of the CKM\nmatrix element |V_{us}| from experimental data. Our result is based on the\ngauge configurations produced by the European Twisted Mass Collaboration with\nN_f=2+1+1 dynamical fermions. We simulated at three different values of the\nlattice spacing and with pion masses as small as 210 MeV. Our preliminary\nestimate for the vector form factor at zero momentum transfer is\nf_+(0)=0.9683(65), where the uncertainty is both statistical and systematic. By\ncombining our result with the experimental value of f_+(0)|V_{us}| we obtain\n|V_{us}|=0.2234(16), which satisfies the unitarity constraint of the Standard\nModel at the permille level.",
        "positive": "Quenched Light Hadron Spectrum with the Wilson Quark Action: Final\n  Results from CP-PACS: We report the final results of the CP-PACS calculation for the quenched light\nhadron spectrum with the Wilson quark action. Our data support the presence of\nquenched chiral singularities, and this motivates us to use mass formulae based\non quenched chiral perturbation theory in order to extrapolate hadron masses to\nthe physical point. Hadron masses and decay constants in the continuum limit\nshow unambiguous systematic deviations from experiment. We also report the\nresults for light quark masses."
    },
    {
        "anchor": "Two-Dimensional Dynamical Triangulation using the Grand-canonical\n  Ensemble: The string susceptibility exponents of dynamically triangulated two\ndimensional surfaces with sphere and torus topology were calculated using the\ngrand-canonical Monte Carlo method. We also simulated the model coupled to\nd-Ising spins (d=1,2,3,5).",
        "positive": "The Sign Problem via Imaginary Chemical Potential: We calculate an analogue of the average phase factor of the staggered fermion\ndeterminant at imaginary chemical potential. Our results from the lattice agree\nwell with the analytical predictions in the microscopic regime for both\nquenched and phase-quenched QCD. We demonstrate that the average phase factor\nin the microscopic domain is dominated by the lowest-lying Dirac eigenvalues."
    },
    {
        "anchor": "Direct evidence for a Coulombic phase in monopole-suppressed SU(2)\n  lattice gauge theory: Further evidence is presented for the existence of a non-confining phase at\nweak coupling in SU(2) lattice gauge theory. Using Monte Carlo simulations with\nthe standard Wilson action, gauge-invariant SO(3)-Z2 monopoles, which are\nstrong-coupling lattice artifacts, have been seen to undergo a percolation\ntransition exactly at the phase transition previously seen using Coulomb-gauge\nmethods, with an infinite lattice critical point near $\\beta = 3.2$. The theory\nwith both Z2 vortices and monopoles and SO(3)-Z2 monopoles eliminated is\nsimulated in the strong coupling ($\\beta = 0$) limit on lattices up to $60^4$.\nHere, as in the high-$\\beta$ phase of the Wilson action theory, finite size\nscaling shows it spontaneously breaks the remnant symmetry left over after\nCoulomb gauge fixing. Such a symmetry breaking precludes the potential from\nhaving a linear term. The monopole restriction appears to prevent the\ntransition to a confining phase at any $\\beta$. Direct measurement of the\ninstantaneous Coulomb potential shows a Coulombic form with moderately running\ncoupling possibly approaching an infrared fixed point of $\\alpha \\sim 1.4$. The\nCoulomb potential is measured to 50 lattice spacings and 2 fm. A short-distance\nfit to the 2-loop perturbative potential is used to set the scale. High\nprecision at such long distances is made possible through the use of open\nboundary conditions, which was previously found to cut random and systematic\nerrors of the Coulomb gauge fixing procedure dramatically. The Coulomb\npotential agrees with the gauge-invariant interquark potential measured with\nsmeared Wilson loops on periodic lattices as far as the latter can be\npractically measured with similar statistics data.",
        "positive": "Isotriplet Dark Matter on the Lattice: SO(4)-gauge theory with two\n  Vector Wilson fermions: We present preliminary results for simulations of SO(4)-gauge theory with two\nDirac Wilson fermions transforming according to the vector representation. We\nmap out the phase diagram including the strong coupling bulk phase transition\nline as well as the zero PCAC-mass line. In addition, we measure the pseudo\nscalar and vector meson masses, and investigate whether the theory features\nchiral symmetry breaking. If the theory is used for breaking the electroweak\nsymmetry dynamically it is the orthogonal group equivalent of the Minimal\nWalking Technicolor model but with the following distinctive features: a] It\nprovides a natural complex weak isotriplet of Goldstone bosons of which the\nneutral component can be identified with a light composite dark matter state;\nb] It is expected to break the global symmetry spontaneously; c] It is free\nfrom fermionic composite states made by a techniglue and a technifermion."
    },
    {
        "anchor": "Massless Composite Fermions in Two Dimensions and the Overlap: There exist chiral gauge models in two dimensions that have massless\ncomposite fermions. Two examples are presented and it is suggested that they be\naccepted as benchmark test-cases for generic proposals of non-perturbatively\nregulating chiral gauge theories in any dimension. We apply the overlap to the\nsimpler of the two benchmarks and present the results of a numerical simulation\nof modest size.",
        "positive": "Dimensional Reduction and the Yang-Mills Vacuum State in 2+1 Dimensions: We propose an approximation to the ground state of Yang-Mills theory,\nquantized in temporal gauge and 2+1 dimensions, which satisfies the Yang-Mills\nSchrodinger equation in both the free-field limit, and in a strong-field zero\nmode limit. Our proposal contains a single parameter with dimensions of mass;\nconfinement via dimensional reduction is obtained if this parameter is\nnon-zero, and a non-zero value appears to be energetically preferred. A method\nfor numerical simulation of this vacuum state is developed. It is shown that if\nthe mass parameter is fixed from the known string tension in 2+1 dimensions,\nthe resulting mass gap deduced from the vacuum state agrees, to within a few\npercent, with known results for the mass gap obtained by standard lattice Monte\nCarlo methods."
    },
    {
        "anchor": "Numerical Methods for the QCD Overlap Operator: I. Sign-Function and\n  Error Bounds: The numerical and computational aspects of the overlap formalism in lattice\nquantum chromodynamics are extremely demanding due to a matrix-vector product\nthat involves the sign function of the hermitian Wilson matrix. In this paper\nwe investigate several methods to compute the product of the matrix\nsign-function with a vector, in particular Lanczos based methods and partial\nfraction expansion methods. Our goal is two-fold: we give realistic comparisons\nbetween known methods together with novel approaches and we present error\nbounds which allow to guarantee a given accuracy when terminating the Lanczos\nmethod and the multishift-CG solver, applied within the partial fraction\nexpansion methods.",
        "positive": "Baryon-baryon potentials in the flavor SU(3) limit from lattice QCD: We investigate baryon-baryon (BB) interactions in the flavor SU(3) symmetric\nworld, by using the 3-flavor full QCD simulations. In the SU(3) limit, six\nindependent two-baryon states exist for a given orbital angular momentum. We\nforcus on S-wave states and extract BB potentials using the method recently\ndeveloped. We discuss the flavor dependence of the potentials, in particular,\nthe strength of the repulsion at short distance. We find that the SU(3) flavor\nstructure of the repulsive core is compatible with that expected from the Pauli\nprinciple for the quarks."
    },
    {
        "anchor": "Parity doubling of nucleons and Delta baryons across the deconfinement\n  phase transition: At zero temperature the negative-parity ground states of the nucleon and\ndelta baryons are non-degenerate with the positive-parity partners due to\nspontaneous breaking of chiral symmetry. However, chiral symmetry is expected\nto be restored at sufficiently high temperature, in particular when going from\nthe hadronic to the quark-gluon plasma (QGP) phase. This would imply that\nchannels with opposite parity become degenerate. We study the nucleon (spin\n$1/2$) and $\\Delta$ (spin $3/2$) baryons in both parity sectors using lattice\nQCD. The range of temperatures spans both the hadronic and QGP phases. Using\nthe FASTSUM anisotropic $N_f = 2 + 1$ ensembles, we analyze the correlation\nfunctions and the spectral functions using respectively exponential fits and\nthe Maximum Entropy Method. We find clear evidence of in-medium effects in the\nhadronic phase, especially for the negative-parity ground state, and of parity\ndoubling in the QGP phase.",
        "positive": "Ghost sector and geometry in minimal Landau gauge: further constraining\n  the infinite-volume limit: We present improved upper and lower bounds for the momentum-space ghost\npropagator of Yang-Mills theories in terms of the two smallest nonzero\neigenvalues (and their corresponding eigenvectors) of the Faddeev-Popov matrix.\nThese results are verified using data from four-dimensional numerical\nsimulations of SU(2) lattice gauge theory in minimal Landau gauge at beta =\n2.2, for lattice sides N = 16, 32, 48 and 64. Gribov-copy effects are discussed\nby considering four different sets of numerical minima. We then present a lower\nbound for the smallest nonzero eigenvalue of the Faddeev-Popov matrix in terms\nof the smallest nonzero momentum on the lattice and of a parameter\ncharacterizing the geometry of the first Gribov region $\\Omega$. This allows a\nsimple and intuitive description of the infinite-volume limit in the ghost\nsector. In particular, we show how nonperturbative effects may be quantified by\nthe rate at which typical thermalized and gauge-fixed configurations approach\nthe boundary of Omega, known as the first Gribov horizon. As a result, a simple\nand concrete explanation emerges for why lattice studies do not observe an\nenhanced ghost propagator in the deep infrared limit. Most of the simulations\nhave been performed on the Blue Gene/P--IBM supercomputer shared by Rice\nUniversity and S\\~ao Paulo University."
    },
    {
        "anchor": "The conserved axial current in the presence of multiple chiral\n  symmetries: In response to a recent work by Mandula, we investigate whether there are any\nambiguities in the expression for the pion mass resulting from multiple chiral\nsymmetries. If the conserved current for Ginsparg Wilson chiral symmetries is\ncalculated in the usual way, different expressions of the chiral symmetry lead\nto different currents. This implies an ambiguity in the definition of the pion\nand pion decay constant for all Ginsparg-Wilson expressions of the Dirac\noperator, including the overlap operator on the lattice (although all these\ncurrents would have the same continuum limit). We use a renormalisation group\nmapping procedure to consider local chiral symmetry transformations for a\ncontinuum Ginsparg-Wilson \"Dirac-operator.\" We find that this naturally leads\nto an expression for the conserved current which is independent of which of the\nGinsparg-Wilson symmetries is chosen. We recover the standard expressions for\nthe massive Dirac operator, propagator, and chiral condensate. Our main\nconclusion is that, when the currents are properly constructed and consistently\napplied, no observable depends on which Mandula symmetry is used; at least in\nthese continuum Ginsparg-Wilson theories. We will consider whether the same\nargument applies to lattice theories in a subsequent paper.",
        "positive": "Efficient simulation of relativistic fermions via vertex models: We have developed an efficient simulation algorithm for strongly interacting\nrelativistic fermions in two-dimensional field theories based on a formulation\nas a loop gas. The loop models describing the dynamics of the fermions can be\nmapped to statistical vertex models and our proposal is in fact an efficient\nsimulation algorithm for generic vertex models in arbitrary dimensions. The\nalgorithm essentially eliminates critical slowing down by sampling two-point\ncorrelation functions and it allows simulations directly in the massless limit.\nMoreover, it generates loop configurations with fluctuating topological\nboundary conditions enabling to simulate fermions with arbitrary periodic or\nanti-periodic boundary conditions. As illustrative examples, the algorithm is\napplied to the Gross-Neveu model and to the Schwinger model in the strong\ncoupling limit."
    },
    {
        "anchor": "The Deconfinement Transition in SU(4) Lattice Gauge Theory: The deconfinement transition in SU(4) lattice gauge theory is studied on\nN_s^3 X N_t lattices with N_s = 8-16 and N_t = 4-8 using a modified Wilson\naction which is expected to have no bulk transitions. The peak of\nsusceptibility \\chi_{|L|} is found to increase linearly with spatial volume for\nN_t = 4, 5, and 6, indicating a first order deconfinement phase transition. The\nlatent heat is estimated to be approximately 2/3 of the corresponding ideal gas\nenergy density at T_c.",
        "positive": "Error Bounds for the Sign Function: The Overlap operator fulfills the Ginsparg-Wilson relation exactly and\ntherefore represents an optimal discretization of the QCD Dirac operator with\nrespect to chiral symmetry. When computing propagators or in HMC simulations,\nwhere one has to invert the overlap operator using some iterative solver, one\nhas to approxomate the action of the sign function of the (symmetrized) Wilson\nfermion matrix Q on a vector b in each iteration. This is usually done\niteratively using a \"primary\" Lanczos iteration. In this process, it is very\nimportant to have good stopping criteria which allow to reliably assess the\nquality of the approximation to the action of the sign function computed so\nfar. In this work we show how to cheaply recover a secondary Lanczos process,\nstarting at an arbitrary Lanczos vector of the primary process and how to use\nthis secondary process to efficiently obtain computable error estimates and\nerror bounds for the Lanczos approximations to sign(Q)b, where the sign\nfunction is approximated by the Zolotarev rational approximation."
    },
    {
        "anchor": "Lattice QCD with the Overlap Fermions at Strong Gauge Coupling (II): In the previous paper we developed a strong-coupling expansion for the\nlattice QCD with the overlap fermions and showed that L\\\"usher's \"extended\"\nchiral symmetry is spontaneously broken in some parameter region of the overlap\nfermions. In this paper, we derive a low-energy effective action of hadrons and\nshow that there exist quasi-Nambu-Goldstone bosons which are identified as the\npions. The pion field is a {\\em nonlocal} composite field of quark and\nanti-quark even at the strong-coupling limit because of the nonlocality of the\noverlap fermion formalism and L\\\"usher's chiral symmetry. The pions become\nmassless in the limit of the vanishing bare-quark mass as it is desired. We\nfurthermore examine symmetries of the overlap fermions with the hopping\nexpansion and argue that there appear no other massless modes other than the\npions.",
        "positive": "Properties of Scalar-Quark Systems in SU(3)c Lattice QCD: We perform the first study for the bound states of colored scalar particles\n$\\phi$ (\"scalar quarks\") in terms of mass generation with quenched SU(3)$_c$\nlattice QCD. We investigate the bound states of $\\phi$, $\\phi^\\dagger\\phi$ and\n$\\phi\\phi\\phi$ (\"scalar-quark hadrons\"), as well as the bound states of $\\phi$\nand quarks $\\psi$, i.e., $\\phi^\\dagger\\psi$, $\\psi\\psi\\phi$ and $\\phi\\phi\\psi$\n(\"chimera hadrons\"). All these new-type hadrons including $\\phi$ have a large\nmass of several GeV due to large quantum corrections by gluons, even for zero\nbare scalar-quark mass $m_\\phi=0$ at $a^{-1}\\sim 1{\\rm GeV}$. We find a similar\n$m_\\psi$-dependence between $\\phi^\\dagger\\psi$ and $\\phi\\phi\\psi$, which\nindicates their similar structure due to the large mass of $\\phi$. From this\nstudy, we conjecture that all colored particles generally acquire a large\neffective mass due to dressed gluons."
    },
    {
        "anchor": "Constraints for the semileptonic $B \\to D^{(*)}$ form factors from\n  lattice QCD simulations of two-point correlation functions: In this work we present the first non-perturbative determination of the\nhadronic susceptibilities that constrain the form factors entering the\nsemileptonic $B \\to D^{(*)} \\ell \\nu_\\ell $ transitions due to unitarity and\nanalyticity. The susceptibilities are obtained by evaluating moments of\nsuitable two-point correlation functions obtained on the lattice. Making use of\nthe gauge ensembles produced by the Extended Twisted Mass Collaboration with\n$N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a\n\\simeq 0.062, 0.082, 0.089$ fm) and with pion masses in the range $\\simeq 210 -\n450$ MeV, we evaluate the longitudinal and transverse susceptibilities of the\nvector and axial-vector polarization functions at the physical pion point and\nin the continuum and infinite volume limits. The ETMC ratio method is adopted\nto reach the physical $b$-quark mass $m_b^{phys}$. At zero momentum transfer\nfor the $b \\to c$ transition we get $\\chi_{0^+}(m_b^{phys}) = 7.58\\,(59) \\cdot\n10^{-3}$, $\\chi_{1^-}(m_b^{phys}) = 6.72\\,(41) \\cdot 10^{-4}$ GeV$^{-2}$,\n$\\chi_{0^-}(m_b^{phys}) = 2.58\\,(17) \\cdot 10^{-2}$ and $\\chi_{1^+}(m_b^{phys})\n= 4.69\\,(30) \\cdot 10^{-4}$ GeV$^{-2}$ for the scalar, vector, pseudoscalar and\naxial susceptibilities, respectively. In the case of the vector and\npseudoscalar channels the one-particle contributions due to $B_c^*$- and\n$B_c$-mesons are evaluated and subtracted to improve the bounds, obtaining:\n$\\chi_{1^-}^{sub}(m_b^{phys}) = 5.84\\,(44) \\cdot 10^{-4}$ GeV$^{-2}$ and\n$\\chi_{0^-}^{sub}(m_b^{phys}) = 2.19\\,(19) \\cdot 10^{-2}$.",
        "positive": "Microscopic Universality and the Chiral Phase Transition in two Flavor\n  QCD: We re-analyze data from available finite-temperature QCD simulations near the\nchiral transition, with the help of Chiral Random Matrix Theory (chRMT).\nStatistical properties of the lowest-lying eigenvalues of the staggered Dirac\noperator for SU(3) lattice gauge theory with dynamical fermions are examined.\nWe consider temperatures below, near, and above the critical temperature $T_c$\nfor the chiral phase transition. Below and above $T_c$ the statistics are in\nagreement with the exact analytical predictions in the microscopic scaling\nregime. Above $T_c$ we observe a gap in the spectral density and a distribution\ncompatible with the Airy distribution. Near $T_c$ the eigenvalue correlations\nappear inconsistent with chRMT."
    },
    {
        "anchor": "Staggered fermion approach to chiral gauge theories on the lattice: The staggered fermion approach to build models with chiral fermions is\nbriefly reviewed. The method is tested in a U(1) model with axial vector\ncoupling in two and four dimensions.",
        "positive": "Matrix elements of the electromagnetic operator between kaon and pion\n  states: We compute the matrix elements of the electromagnetic (EM) operator (\\bar{s}\nF{\\mu \\nu} \\sigma{\\mu \\nu} d) between kaon and pion states, using lattice QCD\nwith maximally twisted-mass fermions and two flavors of dynamical quarks (Nf =\n2). The operator is renormalized non-perturbatively in the RI'/MOM scheme and\nour simulations cover pion masses as light as 270 MeV and three values of the\nlattice spacing from ~ 0.07 up to ~ 0.1 fm. At the physical point our result\nfor the corresponding tensor form factor at zero-momentum transfer is\nfT{K\\pi}(0) = 0.417 (14_stat) (5_syst), where the systematic error does not\ninclude the effect of quenching the strange and charm quarks. Our result\ndiffers significantly from the old quenched result fT{K\\pi}(0) = 0.78 (6)\nobtained by the SPQcdR Collaboration with pion masses above 500 MeV. We\ninvestigate the source of this difference and conclude that it is mainly\nrelated to the chiral extrapolation. We also study the tensor charge of the\npion and obtain the value fT{\\pi\\pi}(0) = 0.195 (8_stat) (6_syst) in good\nagreement with, but more accurate than the result fT{\\pi\\pi}(0) = 0.216 (34)\nobtained by the QCDSF Collaboration using higher pion masses."
    },
    {
        "anchor": "Lattice QCD based on OpenCL: We present an OpenCL-based Lattice QCD application using a heatbath algorithm\nfor the pure gauge case and Wilson fermions in the twisted mass formulation.\nThe implementation is platform independent and can be used on AMD or NVIDIA\nGPUs, as well as on classical CPUs. On the AMD Radeon HD 5870 our double\nprecision dslash implementation performs at 60 GFLOPS over a wide range of\nlattice sizes. The hybrid Monte-Carlo presented reaches a speedup of four over\nthe reference code running on a server CPU.",
        "positive": "QCD with Two Light Dynamical Chirally Improved Quarks: Baryons: We present a study of baryon ground states and low lying excitations of\nnon-strange and strange baryons. The results are based on seven gauge field\nensembles with two dynamical light Chirally Improved (CI) quarks corresponding\nto pion masses between 255 and 596 MeV and a strange valence quark with mass\nfixed by the Omega baryon. The lattice spacing varies between 0.1324 and 0.1398\nfm. Given in lattice units, the bulk of our results are for size 16^3\\times 32,\nfor two ensembles with light pion masses (255 and 330 MeV) we also use\n24^3\\times 48 lattices and perform an infinite volume extrapolation. We derive\nenergy levels for the spin 1/2 and 3/2 channels for both parities. In general,\nour results in the infinite volume limit compare well with experiment. We\nanalyze the flavor symmetry content by identifying the singlet/octet/decuplet\ncontributions of the resulting eigenstates. The ground states compositions\nagree with quark model expectations. In some cases the excited states, however,\ndisagree and we discuss possible reasons."
    },
    {
        "anchor": "Mass gap in compact U(1) Model in (2+1) dimensions: A numerical study of low-lying glueball masses of compact U(1) lattice gauge\ntheory in (2+1) dimensions is performed using Standard Path integral Monte\nCarlo techniques. The masses are extracted, at fixed (low) temperature, from\nsimulations on anisotropic lattices, with temporal lattice spacing much smaller\nthan the spatial ones. Convincing evidence of the scaling behaviour in the\nantisymmetric mass gap is observed over the range $1.4<\\beta <2.25$. The\nobserved behaviour is very consistent with asymptotic form predicted by G{\\\"\no}pfert and Mack. Extrapolations are made to the \"Hamiltonian\" limit, and the\nresults are compared with previous estimates obtained by many other Hamiltonian\nstudies.",
        "positive": "Nuclear forces in the parity odd sector and the LS forces: In this paper, we report our first attempt at determining NN potentials in\nthe parity odd sector including the spin-orbit force in lattice QCD, employing\nthe method to extract successfully parity even NN potentials from\nNambu-Bethe-Salpeter (NBS) wave functions through the Schr\\\"odinger equation.\nUsing Nf = 2 CP-PACS gauge configurations on a 16^3 x 32 lattice at a = 0.16 fm\nand m_\\pi \\cong 1.1 GeV, we calculate central, tensor and spin-orbit potentials\nin the parity odd sector. Although statistical errors are still large, we\nobserve that the qualitative features of these potentials roughly agree with\nthose of phenomenological potentials."
    },
    {
        "anchor": "Perfect topological charge for asymptotically free theories: The classical equations of motion of the perfect lattice action in\nasymptotically free $d=2$ spin and $d=4$ gauge models possess scale invariant\ninstanton solutions. This property allows the definition of a topological\ncharge on the lattice which is perfect in the sense that no topological defects\nexist. The basic construction is illustrated in the $d=2$ O(3) non--linear\n$\\sigma$--model and the topological susceptibility is measured to high\nprecision in the range of correlation lengths $\\xi \\in (2 - 60)$. Our results\nstrongly suggest that the topological susceptibility is not a physical quantity\nin this model.",
        "positive": "Performance Portability Strategies for Grid C++ Expression Templates: One of the key requirements for the Lattice QCD Application Development as\npart of the US Exascale Computing Project is performance portability across\nmultiple architectures. Using the Grid C++ expression template as a starting\npoint, we report on the progress made with regards to the Grid GPU offloading\nstrategies. We present both the successes and issues encountered in using CUDA,\nOpenACC and Just-In-Time compilation. Experimentation and performance on GPUs\nwith a SU(3)$\\times$SU(3) streaming test will be reported. We will also report\non the challenges of using current OpenMP 4.x for GPU offloading in the same\ncode."
    },
    {
        "anchor": "Ginsparg-Wilson Fermions: A study in the Schwinger Model: Qualitative features of Ginsparg-Wilson fermions, as formulated by Neuberger,\ncoupled to two dimensional U(1) gauge theory are studied. The role of the\nWilson mass parameter in changing the number of massless flavors in the theory\nand its connection with the index of the Dirac operator is studied. Although\nthe index of the Dirac operator is not related to the geometric definition of\nthe topological charge for strong couplings, the two start to agree as soon as\none goes to moderately weak couplings. This produces the desired singularity in\nthe quenched chiral condensate which appears to be very difficult to reproduce\nwith staggered fermions. The fermion determinant removes the singularity and\nreproduces the known chiral condensate and the meson mass within understandable\nerrors.",
        "positive": "Gauge invariant 'monopoles' and color confinement mechanism: The dual Meissner effect is described and numerically observed in a\ngauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD. A\ngauge-invariant monopole-like quantity on the lattice is defined by a\ngauge-invariant Abelian-like field strength. The Abelian-like field strength is\nexpressed in terms of a unit-vector in color space which is constructed by a\nnon-Abelian field strength itself. It is just equal to the absolute value of\nthe corresponding non-Abelian field strength except for the sign. In this note\nwe show the theoretical background and most numerical results will be published\nin a separate report \\cite{Suzuki:2005lat052} in this conference."
    },
    {
        "anchor": "Scaling behavior of quark propagator in full QCD: We study the scaling behavior of the quark propagator on two lattices with\nsimilar physical volume in Landau gauge with 2+1 flavors of dynamical quarks in\norder to test whether we are close to the continuum limit for these lattices.\nWe use configurations generated with an improved staggered (``Asqtad'') action\nby the MILC collaboration. The calculations are performed on $28^3\\times 96$\nlattices with lattice spacing $a = 0.09$ fm and on $20^3\\times 64$ lattices\nwith lattice spacing $a = 0.12$ fm. We calculate the quark mass function,\n$M(q^2)$, and the wave-function renormalization function, $Z(q^2)$, for a\nvariety of bare quark masses. Comparing the behavior of these functions on the\ntwo sets of lattices we find that both $Z(q^2)$ and $M(q^2)$ show little\nsensitivity to the ultraviolet cutoff.",
        "positive": "The QCD string tension curve, the ferromagnetic magnetization, and the\n  quark-antiquark confining potential at finite Temperature: We study the string tension as a function of temperature, fitting the SU(3)\nlattice QCD finite temperature free energy potentials computed by the Bielefeld\ngroup. We compare the string tension points with order parameter curves of\nferromagnets, superconductors or string models, all related to confinement. We\nalso compare the SU(3) string tension with the one of SU(2) Lattice QCD. With\nthe curve providing the best fit to the finite temperature string tensions, the\nspontaneous magnetization curve, we then show how to include finite\ntemperature, in the state of the art confining and chiral invariant quark\nmodels."
    },
    {
        "anchor": "QCD at finite temperature and partially negative flavour numbers: We study dynamical fermion effects in lattice QCD at finite temperature. The\nmethod adopted is basically the extrapolation from negative flavour numbers\nalready tested at zero temperature and based on the simulation of local bosonic\ntheories, with an essential difference. With an appropriate choice of the\nboundary conditions on the bosonic fields, called ``bermions'', it is possible\nto separate the $Z_3$ breaking contribution of fermion loops to the effective\naction from the one conserving $Z_3$: the former is simulated exactly at a\nfixed positive and even flavour number, while the extrapolation from negative\nflavour numbers is made only on the $Z_3$ invariant part of the action. We test\nthis approach by comparing our results on a $16^3\\times 2$ lattice with those\nfrom a hopping parameter expansion and our results on a $16^3\\times 4$ lattice\nwith those of direct Monte Carlo simulations including the fermion determinant.",
        "positive": "The pion scalar form factor with $N_f=2+1$ Wilson fermions: We report preliminary results from an analysis of the pion scalar form factor\ncomputed on a set of the $\\mathrm{tr}[M]=\\mathrm{const}$ CLS gauge ensembles\nwith $N_f=2+1$ Wilson Clover-improved sea quarks. The calculations are carried\nout for light quarks masses corresponding to $M_\\pi\\approx 0.130\\mathrm{MeV}\n\\ldots 350\\mathrm{MeV}$, four values of the lattice spacing\n$a\\approx0.049\\mathrm{fm}\\ldots0.086\\mathrm{fm}$ and a large range of physical\nvolumes. A fine-grained momentum resolution is achieved by allowing for\nnon-vanishing sink momenta and by including two particularly large and fine\nboxes close to physical quark masses (i.e. $T\\times L^3 = 192\\times 96^3$,\n$M_\\pi \\le 172\\mathrm{MeV}$, $a \\le 0.064\\mathrm{fm}$). The pertinent\nquark-disconnected contributions have been computed to high precision using a\nscheme combining 1.) the one-end trick on stochastic volume sources for the\ncomputation of differences between two quark flavors with 2.) the hopping\nparameter expansion and hierarchical probing to evaluate the loops for the\nheaviest, single quark flavor."
    },
    {
        "anchor": "Accelerating lattice QCD simulations with 2 flavours of staggered\n  fermions on multiple GPUs using OpenACC - a first attempt: We present the results of an effort to accelerate a Rational Hybrid Monte\nCarlo (RHMC) program for lattice quantum chromodynamics (QCD) simulation for 2\nflavours of staggered fermions on multiple Kepler K20X GPUs distributed on\ndifferent nodes of a Cray XC30. We do not use CUDA but adopt a higher level\ndirective based programming approach using the OpenACC platform. The lattice\nQCD algorithm is known to be bandwidth bound; our timing results illustrate\nthis clearly, and we discuss how this limits the parallelization gains. We\nachieve more than a factor three speed-up compared to the CPU only MPI program.",
        "positive": "The triton in a finite volume: Understanding the volume dependence of the triton binding energy is an\nimportant step towards lattice simulations of light nuclei. We calculate the\ntriton binding energy in a finite cubic box with periodic boundary conditions\nto leading order in the pionless effective field theory. Higher order\ncorrections are estimated and the proper renormalization of our results is\nverified explicitly. We present results for the physical triton as well as for\nthe pion-mass dependence of the triton spectrum near the ``critical'' pion\nmass, Mpi_c ~ 197 MeV, where chiral effective field theory suggests that the\nnucleon-nucleon scattering lengths in the singlet- and triplet-channels diverge\nsimultaneously. An extension of the Luescher formula to the three-body system\nis implicit in our results."
    },
    {
        "anchor": "First lattice calculation of the QED corrections to leptonic decay rates: The leading-order electromagnetic and strong isospin-breaking corrections to\nthe ratio of $K_{\\mu 2}$ and $\\pi_{\\mu 2}$ decay rates are evaluated for the\nfirst time on the lattice, following a method recently proposed. The lattice\nresults are obtained using the gauge ensembles produced by the European Twisted\nMass Collaboration with $N_f = 2 + 1 + 1$ dynamical quarks. Systematics effects\nare evaluated and the impact of the quenched QED approximation is estimated.\nOur result for the correction to the tree-level $K_{\\mu 2} / \\pi_{\\mu 2}$ decay\nratio is $-1.22\\,(16) \\%$ to be compared to the estimate $-1.12\\,(21) \\%$ based\non Chiral Perturbation Theory and adopted by the Particle Data Group.",
        "positive": "Lattice simulations of Born-Infeld non-linear QED: Born-Infeld non-linear electrodynamics was introduced to render the self\nenergy of a point particle finite. It has recently been revived as a field\ntheory for branes and strings. We quantize this theory on a Euclidean\nspace-time lattice, using Metropolis Monte-Carlo simulations to measure the\nproperties of the quantum field theory. Luscher-Weisz methods are used to\nmeasure the electromagnetic fields from a static point charge. The D field from\na point charge appears to be identical to that for the normal Maxwell\nLagrangian. The E field is enhanced by quantum fluctuations, and shows short\ndistance screening as it does in the classical theory."
    },
    {
        "anchor": "Nonperturbative comparison of clover and HISQ quarks in lattice QCD and\n  the properties of the phi meson: We compare correlators for pseudoscalar and vector mesons made from valence\nstrange quarks using the clover quark and highly improved staggered quark\n(HISQ) formalisms in full lattice QCD. We use fully nonperturbative methods to\nnormalise vector and axial vector current operators made from HISQ quarks,\nclover quarks and from combining HISQ and clover fields. This allows us to test\nexpectations for the renormalisation factors based on perturbative QCD, with\nimplications for the error budget of lattice QCD calculations of the matrix\nelements of clover-staggered $b$-light weak currents, as well as further HISQ\ncalculations of the hadronic vacuum polarisation. We also compare the approach\nto the (same) continuum limit in clover and HISQ formalisms for the mass and\ndecay constant of the $\\phi$ meson. Our final results for these parameters,\nusing single-meson correlators and neglecting quark-line disconnected diagrams\nare: $m_{\\phi} =$ 1.023(6) GeV and $f_{\\phi} = $ 0.238(3) GeV in good agreement\nwith experiment. The results come from calculations in the HISQ formalism using\ngluon fields that include the effect of $u$, $d$, $s$ and $c$ quarks in the sea\nwith three lattice spacing values and $m_{u/d}$ values going down to the\nphysical point.",
        "positive": "Chiral fermions in two dimensions?: Quenched studies of a global U(1) symmetric Wilson-Yukawa model in two\ndimensions show no evidence of a charged fermion in the vortex phase at strong\nWilson-Yukawa coupling while there is strong indication of a massive neutral\nfermion. However, with the U(1)$_L$ gauge field turned on, we use dimensional\narguments to suggest that the neutral fermion appears to couple chirally to a\nmassive vector boson state."
    },
    {
        "anchor": "Antiferromagnetic Ising model in an imaginary magnetic field: We study the two-dimensional antiferromagnetic Ising model with a purely\nimaginary magnetic field, which can be thought of as a toy model for the usual\n$\\theta$ physics. Our motivation is to have a benchmark calculation in a system\nwhich suffers from a strong sign problem, so that our results can be used to\ntest Monte Carlo methods developed to tackle such problems. We analyze here\nthis model by means of analytical techniques, computing exactly the first eight\ncumulants of the expansion of the effective Hamiltonian in powers of the\ninverse temperature, and calculating physical observables for a large number of\ndegrees of freedom with the help of standard multi-precision algorithms. We\nreport accurate results for the free energy density, internal energy, standard\nand staggered magnetization, and the position and nature of the critical line,\nwhich confirm the mean-field qualitative picture, and which should be\nquantitatively reliable, at least in the high-temperature regime, including the\nentire critical line.",
        "positive": "Four-Fermion Theories with Exact Chiral Symmetry in Three Dimensions: We investigate a class of four-fermion theories which includes well-known\nmodels like the Gross-Neveu model and the Thirring model. In three spacetime\ndimensions, they are used to model interesting solid state systems like high\ntemperature superconductors and graphene. Additionally, they serve as toy\nmodels to study chiral symmetry breaking (CSB).\n  For any number of fermion flavours the Gross-Neveu model has a broken and a\nsymmetric phase, while the existence of a broken phase in the Thirring model\ndepends on the number of flavours. The critical number of fermion flavours\nbeyond which there exists no CSB is still subject of ongoing discussions. Using\nSLAC fermions we simulate the Thirring model with exact chiral symmetry. To\nobtain a chiral condensate one can introduce a symmetry-breaking mass term and\ncarefully study the limits of infinite lattice and zero-mass. So far, we did\nnot see CSB within this approach for the Thirring model with 2 or more\n(reducible) flavours.\n  The talk presents alternative approaches to investigate these findings. We\nemploy certain Fierz identities to map the Thirring model into equivalent\nfour-fermion models, for which the chiral condensate does not seem to vanish.\nIn the new formulations based on reshuffled degrees of freedom we find a sign\nproblem (which is not present in the original formulation). For this reason we\ndeveloped an algorithm similar to fermion bags, which may solve this problem.\nAs a further approach, we embed the multi-flavour Thirring model in a larger\nclass of four-fermion theories to study the chiral symmetry and its breaking in\na wider context."
    },
    {
        "anchor": "Multi-Quark Energies in SU(2) Lattice Gauge Theory: Energies of four-quark systems have been extracted in a quenched SU(2)\nlattice Monte Carlo calculation for two different geometries, rectangular and\ncolinear, with $\\beta=2.4$ and lattice size $16^3\\times 32$. Also, by going to\na lattice $24^3\\times 32$ and to $\\beta=2.5$, the effect of the finite lattice\nsize and scaling are checked. An attempt is made to understand these results in\nterms of a model based on interquark two-body potentials but modified very\nsignificantly by a phenomenological gluon-field overlap factor.",
        "positive": "Conformal vs confining scenario in SU(2) with adjoint fermions: The masses of the lowest-lying states in the meson and in the gluonic sector\nof an SU(2) gauge theory with two Dirac flavors in the adjoint representation\nare measured on the lattice at a fixed value of the lattice coupling $\\beta =\n4/g_0^2 = 2.25$ for values of the bare fermion mass $m_0$ that span a range\nbetween the quenched regime and the massless limit, and for various lattice\nvolumes. Even for light constituent fermions the lightest glueballs are found\nto be lighter than the lightest mesons. Moreover, the string tension between\ntwo static fundamental sources strongly depends on the mass of the dynamical\nfermions and becomes of the order of the inverse squared lattice linear size\nbefore the chiral limit is reached. The implications of these findings for the\nphase of the theory in the massless limit are discussed and a strategy for\ndiscriminating between the (near--)conformal and the confining scenario is\noutlined."
    },
    {
        "anchor": "Strong-coupling Analysis of Parity Phase Structure in Staggered-Wilson\n  Fermions: We study strong-coupling lattice QCD with staggered-Wilson fermions, with\nemphasis on discrete symmetries and possibility of their spontaneous breaking.\nWe perform hopping parameter expansion and effective potential analyses in the\nstrong-coupling limit. From gap equations we find nonzero pion condensate in\nsome range of a mass parameter, which indicates existence of the parity-broken\nphase in lattice QCD with staggered-Wilson fermions. We also find massless\npions and PCAC relations around second-order phase boundary. These results\nsuggest that we can take a chiral limit by tuning a mass parameter in lattice\nQCD with staggered-Wilson fermions as with the Wilson fermion.",
        "positive": "Multilevel Monte Carlo for quantum mechanics on a lattice: Monte Carlo simulations of quantum field theories on a lattice become\nincreasingly expensive as the continuum limit is approached since the cost per\nindependent sample grows with a high power of the inverse lattice spacing.\nSimulations on fine lattices suffer from critical slowdown, the rapid growth of\nautocorrelations in the Markov chain. This causes a strong increase in the\nnumber of lattice configurations that have to be generated to obtain\nstatistically significant results. This paper discusses hierarchical sampling\nmethods to tame the growth in autocorrelations. Combined with multilevel\nvariance reduction, this significantly reduces the computational cost of\nsimulations for given tolerances $\\epsilon_{\\text{disc}}$ on the discretisation\nerror and $\\epsilon_{\\text{stat}}$ on the statistical error. For observables\nwith lattice errors of order $\\alpha$ and integrated autocorrelation times that\ngrow like $\\tau_{\\mathrm{int}}\\propto a^{-z}$, multilevel Monte Carlo (MLMC)\nreduces the cost from\n$\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}\\epsilon_{\\text{disc}}^{-(1+z)/\\alpha})$\nto $\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}\\vert\\log \\epsilon_{\\text{disc}}\n\\vert^2+\\epsilon_{\\text{disc}}^{-1/\\alpha})$ or\n$\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}+\\epsilon_{\\text{disc}}^{-1/\\alpha})$.\nHigher gains are expected for simulations of quantum field theories in $D$\ndimensions. The efficiency of the approach is demonstrated on two model\nsystems, including a topological oscillator that is badly affected by critical\nslowdown from topological charge freezing. On fine lattices, the new methods\nare orders of magnitude faster than standard Hybrid Monte Carlo sampling. For\nhigh resolutions, MLMC can be used to accelerate even the cluster algorithm for\nthe topological oscillator. Performance is further improved through\nperturbative matching which guarantees efficient coupling of theories on the\nmultilevel hierarchy."
    },
    {
        "anchor": "Pion form factor and charge radius from Lattice QCD at physical point: We present our results on the electromagnetic form factor of pion over a wide\nrange of $Q^2$ using lattice QCD simulations with Wilson-clover valence quarks\nand HISQ sea quarks. We study the form factor at the physical point with a\nlattice spacing $a=0.076$ fm. To study the lattice spacing and quark mass\neffects, we also present results for 300 MeV pion at two different lattice\nspacings $a=0.04$ and 0.06 fm. The lattice calculations at the physical quark\nmass appear to agree with the experimental results. Through fits to the form\nfactor, we estimate the charge radius of pion for physical pion mass to be\n$\\langle r_{\\pi}^2 \\rangle=0.42(2)~{\\rm fm}^2$.",
        "positive": "Nonperturbative Renormalisation of Composite Operators in Lattice QCD: We investigate the nonperturbative renormalisation of composite operators in\nlattice QCD restricting ourselves to operators that are bilinear in the quark\nfields. These include operators which are relevant to the calculation of\nmoments of hadronic structure functions. The computations are based on Monte\nCarlo simulations using quenched Wilson fermions."
    },
    {
        "anchor": "Determining the QCD coupling from lattice vacuum polarization: The QCD coupling appears in the perturbative expansion of the current-current\ntwo-point (vacuum polarization) function. Any lattice calculation of vacuum\npolarization is plagued by several competing non-perturbative effects at small\nmomenta and by discretization errors at large momenta. We work in an\nintermediate region, computing the vacuum polarization for many off-axis\nmomentum directions on the lattice. Having many momentum directions provides a\nway to monitor and account for lattice artifacts. Our results are competitive\nwith, and have certain systematic advantages over, the alternate\nphenomenological determination of the strong coupling from the same light quark\nvacuum polarization produced by sum rule analyses of hadronic tau decay data.",
        "positive": "Domain Wall Fermions and Chiral Gauge Theories: We review the status of the domain wall fermion approach to construct chiral\ngauge theories on the lattice. In this model an extra, fifth dimension is added\nand our 4-dimensional world lives on a domainwall induced by a soliton shaped\nmass defect that depends on the extra dimension only. We demonstrate that the\ndomain wall model gives the correct anomaly structure when external gauge\nfields are used. We discuss two ways of adding dynamical gauge fields aiming at\na lattice regularized chiral gauge theory. An approach is presented to keep the\nlattice infinite by regarding the fifth direction as the time-axis of a\n4-dimensional Hamiltonian. Finally, a prospect to use domain wall fermions for\nsimulating QCD is given."
    },
    {
        "anchor": "Comparison of different lattice definitions of the topological charge: We present a comparison of different definitions of the topological charge on\nthe lattice, using a small-volume ensemble with 2 flavours of dynamical twisted\nmass fermions. The investigated definitions are: index of the overlap Dirac\noperator, spectral projectors, spectral flow of the Hermitian Wilson-Dirac\noperator and field theoretic with different kinds of smoothing of gauge fields\n(HYP and APE smearings, gradient flow, cooling). We also show some results on\nthe topological susceptibility.",
        "positive": "Pion electric polarizabilities from lattice QCD: We report a first principle lattice calculation of the pion electric\npolarizability $\\alpha_\\pi$ at the physical pion mass. First, we derive the\nmaster formula, which relates the pion polarizabilities with the position space\nhadronic Compton tensor, $\\langle \\pi | J_\\mu(x) J_\\nu(0) | \\pi \\rangle$. The\nfinite volume error of the master formula is exponentially suppressed by the\nspatial extent of the lattice. Then, the hadronic tensor is calculated using\ndomain wall fermions (DWF) directly at physical pion mass. The gauge ensembles\nare generated by the RBC-UKQCD collaborations."
    },
    {
        "anchor": "Gauge field topology and the hadron spectrum: Topologically non-trivial gauge field configurations are an interesting\naspect of non-abelian gauge theories. These become particularly important upon\nquantizing the theory, especially through their effect on the pseudo-scalar\nspectrum. These effects are closely tied to chiral anomalies and the\npossibility of CP violation in the strong interactions.",
        "positive": "Form factors for semileptonic B-decays with HISQ light quarks and clover\n  b-quarks in Fermilab interpretation: We compute the vector, scalar, and tensor form factors for the $B\\to \\pi$,\n$B\\to K$, and $B_s\\to K$ amplitudes, which are needed to describe semileptonic\n$B$-meson decay rates for both the charged and neutral current cases. We use\nthe highly improved staggered quark (HISQ) action for the sea and light valence\nquarks. The bottom quark is described by the clover action in the Fermilab\ninterpretation. Simulations are carried out on $N_f = 2+1+1$ MILC HISQ\nensembles at approximate lattice spacings from $0.15$ fm down to $0.057$ fm. We\npresent blinded preliminary results for the form factors."
    },
    {
        "anchor": "Chiral logs with staggered fermions: We compute chiral logarithms in the presence of \"taste\" symmetry breaking of\nstaggered fermions. The lagrangian of Lee and Sharpe is generalized and then\nused to calculate the logs in $\\pi$ and $K$ masses. We correct an error in Ref.\n[1] [C. Bernard, hep-lat/0111051]; the issue turns out to have implications for\nthe comparison with simulations, even at tree level. MILC data with three light\ndynamical flavors can be well fit by our formulas. However, two new chiral\nparameters, which describe order $a^2$ hairpin diagrams for taste-nonsinglet\nmesons, enter in the fits. To obtain precise results for the physical\ncoefficients at order $p^4$, these new parameters will need to be bounded, at\nleast roughly.",
        "positive": "Large-order aspects of the delta-expansion in low-dimensional Ising\n  models: We investigate the large order aspects of the delta-expansion under the\nestimation procession of the critical quantities. As illustrative examples, we\nrevisit one-dimensional Ising model for the analytic study and two-dimensional\nsquare Ising model in the high temperature phase for the numerical experiment\nto large orders. In both models, proposed fundamental base on which the\nestimation protocol should be constructed is investigated in details and\nconfirmed to be valid. In the square lattice model, we present a new protocol\nfor the estimation of critical exponents and temperature."
    },
    {
        "anchor": "Phase transitions in dense 2-colour QCD: We investigate 2-colour QCD with 2 flavours of Wilson fermion at nonzero\ntemperature T and quark chemical potential mu, with a pion mass of 700 MeV\n(m_pi/m_rho=0.8). From temperature scans at fixed mu we find that the critical\ntemperature for the superfluid to normal transition depends only very weakly on\nmu above the onset chemical potential, while the deconfinement crossover\ntemperature is clearly decreasing with mu. We also present results for the\nLandau-gauge gluon propagator in the hot and dense medium.",
        "positive": "Block Spin Effective Action for 4d SU(2) Finite Temperature Lattice\n  Gauge Theory: The Svetitsky-Yaffe conjecture for finite temperature 4d SU(2) lattice gauge\ntheory is confirmed by observing matching of block spin effective actions of\nthe gauge model with those of the 3d Ising model. The effective action for the\ngauge model is defined by blocking the signs of the Polyakov loops with the\nmajority rule. To compute it numerically, we apply a variant of the IMCRG\nmethod of Gupta and Cordery."
    },
    {
        "anchor": "QCD with two dynamical flavors of chirally improved quarks: Considering Ginsparg-Wilson type fermions dynamically in lattice QCD\nsimulations is a challenging task. The hope is to be able to approach smaller\npion masses and to eventually reach physical situations. The price to pay is\nsubstantially higher computational costs. Here we discuss first results of a\ndynamical implementation of the so-called Chirally Improved Fermions, a Dirac\noperator that obeys the Ginsparg-Wilson condition approximately. The simulation\nis for two species of mass-degenerate quarks on 12^3x24 lattices with spatial\nsize up to 1.55 fm. Implementation of the Hybrid Monte-Carlo algorithm and an\nanalysis of the results are presented.",
        "positive": "Decuplet Baryon Masses in Partially Quenched Chiral Perturbation Theory: The masses of the spin-3/2 baryons are calculated to next-to-next-to-leading\norder in heavy baryon chiral perturbation theory and partially quenched heavy\nbaryon chiral perturbation theory. The calculation is performed for three light\nflavors in the isospin limit. These results are necessary for extrapolating QCD\nand partially quenched QCD lattice calculations of the decuplet baryon masses."
    },
    {
        "anchor": "Probing Confinement with Chromomagnetic Fields: Using the lattice Schr\\\"odinger functional we study vacuum dynamics of SU(3)\ngauge theory at finite temperature. The vacuum is probed by means of an\nexternal constant Abelian chromomagnetic field. We find that by increasing the\nstrength of the applied external field the deconfinement temperature decreases\ntowards zero. This implies that strong enough Abelian chromomagnetic fields\ndestroy confinement of color.",
        "positive": "Probing with Penguins: A lattice calculation of the branching ratio for\n  some of the exclusive modes of $b \\to s \u03b3$: We calculate the leading-order matrix element for exclusive decays of $b \\to\ns\\gamma$ in the quenched approximation of lattice QCD on a $24^3\\times48$\nlattice at $\\beta=6.2$, using an O(a)-improved fermion action. The matrix\nelement is used to extract the on-shell form factor $T_1(q^2=0)$ for $B \\to\nK^*\\gamma$ and $B_s \\to \\phi\\gamma$, using two different assumptions about the\n$q^2$ dependence of the form factors for these decays. For $B \\to K^*\\gamma$,\n$T_1(q^2=0)$ is determined to be $0.159^{+34}_{-33}\\pm 0.067$ or\n$0.124^{+20}_{-18} \\pm 0.022$ in the two cases. We find the results to be\nconsistent (in the Standard Model) with the CLEO experimental branching ratio\nof $BR(B\\to K^*\\gamma) = (4.5 \\pm 1.5 \\pm 0.9) \\times 10^{-5}$."
    },
    {
        "anchor": "Qubit regularized $O(N)$ nonlinear sigma models: Motivated by the prospect of quantum simulation of quantum field theories, we\nformulate the $O(N)$ nonlinear sigma model as a \"qubit\" model with an\n$(N+1)$-dimensional local Hilbert space at each lattice site. Using an\nefficient worm algorithm in the worldline formulation, we demonstrate that the\nmodel has a second-order critical point in $(2+1)$ dimensions, where the\ncontinuum physics of the nontrivial $O(N)$ Wilson-Fisher fixed point is\nreproduced. We compute the critical exponents $\\nu$ and $\\eta$ for the $O(N)$\nqubit models up to $N=8$, and find excellent agreement with known results in\nliterature from various analytic and numerical techniques for the $O(N)$\nWilson-Fisher universality class. Our models are suited for studying $O(N)$\nnonlinear sigma models on quantum computers up to $N=8$ in $d=2,3$ spatial\ndimensions.",
        "positive": "A novel method to evaluate real-time path integral for scalar $\u03c6^4$\n  theory: We present a new scheme which numerically evaluates the real-time path\nintegral for $\\phi^4$ real scalar field theory in a lattice version of the\nclosed-time formalism. First step of the scheme is to rewrite the path integral\nin an explicitly convergent form by applying Cauchy's integral theorem to each\nscalar field. In the step an integration path for the scalar field is deformed\non a complex plane such that the $\\phi^4$ term becomes a damping factor in the\npath integral. Secondly the integrations of the complexified scalar fields are\ndiscretized by the Gauss-Hermite quadrature and then the path integral turns\nout to be a multiple sum. Finally in order to efficiently evaluate the\nsummation we apply information compression technique using the singular value\ndecomposition to the discretized path integral, then a tensor network\nrepresentation for the path integral is obtained after integrating the\ndiscretized fields. As a demonstration, by using the resulting tensor network\nwe numerically evaluate the time-correlator in 1+1 dimensional system. For\nconfirmation, we compare our result with the exact one at small spatial volume.\nFurthermore, we show the correlator in relatively large volume using a\ncoarse-graining scheme and verify that the result is stable against changes of\na truncation order for the coarse-graining scheme."
    },
    {
        "anchor": "Radiative leptonic decays on the lattice: Adding a hard photon to the final state of a leptonic pseudoscalar-meson\ndecay lifts the helicity suppression and can provide sensitivity to a larger\nset of operators in the weak effective Hamiltonian. Furthermore, radiative\nleptonic $B$ decays at high photon energy are well suited to constrain the\nfirst inverse moment of the $B$-meson light-cone distribution amplitude, an\nimportant parameter in the theory of nonleptonic $B$ decays. We demonstrate\nthat the calculation of radiative leptonic decays is possible using Euclidean\nlattice QCD, and present preliminary numerical results for $D_s^+ \\to \\ell^+\n\\nu\\gamma$ and $K^- \\to \\ell^-\\bar{\\nu}\\gamma$.",
        "positive": "The complex potential from 2+1 flavor QCD using HTL inspired approach: We have studied finite temperature complex static quark-antiquark potentials\nfor 2+1 flavor QCD using highly improved staggered action with physical strange\nquark masses and light quark masses corresponding to a pion mass of 161 MeV. We\ncalculated the potential using Wilson line correlators fixed in Coulomb gauge.\nFor the extraction, we have used HTL motivated parametrization of the\ncorrelators. We found that the real part of the potential is screened above the\ncrossover temperature and it's close to singlet free energies, whereas the\nimaginary part is increasing with both distance and temperature."
    },
    {
        "anchor": "Non-hermitian Exact Local Bosonic Algorithm for Dynamical Quarks: We present an exact version of the local bosonic algorithm for the simulation\nof dynamical quarks in lattice QCD. This version is based on a non-hermitian\npolynomial approximation of the inverse of the quark matrix. A Metropolis test\ncorrects the systematic errors. Two variants of this test are presented. For\nboth of them, a formal proof is given that this Monte Carlo algorithm converges\nto the right distribution. Simulation data are presented for different lattice\nparameters. The dynamics of the algorithm and its scaling in lattice volume and\nquark mass are investigated.",
        "positive": "Real time evolution and a traveling excitation in SU(2) pure gauge\n  theory on a quantum computer: The Hamiltonian approach can be used successfully to study the real-time\nevolution of a non-Abelian lattice gauge theory on the available noisy quantum\ncomputers. In this work, results from the real-time evolution of SU(2) pure\ngauge theory on IBM hardware are presented. The long real-time evolution\nspanning dozens of Trotter steps with hundreds of CNOT gates and the\nobservation of a traveling excitation on the lattice were made possible by\nusing a collection of error mitigation techniques. Self-mitigation is our novel\ntool, which consists of using the same physics circuit as a noise-mitigation\ncircuit."
    },
    {
        "anchor": "Neutral Kaon Mixing Beyond the Standard Model from 2+1 Flavour Domain\n  Wall QCD: We present preliminary results of a study of Delta S = 2 matrix elements\noriginating from physics beyond the Standard Model. Using 2+1 flavour Domain\nWall Fermions we obtain the non-perturbative renormalisation (mixing) matrix in\nthe RI scheme. We also discuss plans for the chiral extrapolation of the\nrenormalised matrix elements in a partially quenched set-up.",
        "positive": "Volume Dependence of the Axial Charge of the Nucleon: It is shown that the strong volume-dependence of the axial charge of the\nnucleon seen in lattice QCD calculations can be understood quantitatively in\nterms of the pion-induced interactions between neighbouring nucleons. The\nassociated wave function renormalization leads to an increased suppression of\nthe axial charge as the strength of the interaction increases, either because\nof a decrease in lattice size or in pion mass."
    },
    {
        "anchor": "Hybrid Monte Carlo simulation of polymer chains: We develop the hybrid Monte Carlo method for simulations of single\noff-lattice polymer chains. We discuss implementation and choice of simulation\nparameters in some detail. The performance of the algorithm is tested on models\nfor homopolymers with short- or long-range self-repulsion, using chains with\n$16\\le N\\le 512$ monomers. Without excessive fine tuning, we find that the\ncomputational cost grows as $N^{2+z^\\prime}$ with $0.64<z^\\prime<0.84$. In\naddition, we report results for the scaling of the end-to-end distance,\n$r_{1N}\\sim N^\\nu(\\ln N)^{-\\alpha}$.",
        "positive": "Linked cluster expansions beyond nearest neighbour interactions:\n  convergence and graph classes: We generalize the technique of linked cluster expansions on hypercubic\nlattices to actions that couple fields at lattice sites which are not nearest\nneighbours. We show that in this case the graphical expansion can be arranged\nin such a way that the classes of graphs to be considered are identical to\nthose of the pure nearest neighbour interaction. The only change then concerns\nthe computation of lattice imbedding numbers. All the complications that arise\ncan be reduced to a generalization of the notion of free random walks,\nincluding hopping beyond nearest neighbour. Explicit expressions for\ncombinatorical numbers of the latter are given. We show that under some general\nconditions the linked cluster expansion series have a non-vanishing radius of\nconvergence."
    },
    {
        "anchor": "Pion form factors in two-flavor QCD: We present a calculation of pion electromagnetic and scalar form factors in\ntwo-flavor QCD with the non-perturbatively O(a)-improved Wilson fermion. Chiral\nextrapolation of the corresponding charge radius is discussed based on the\nchiral perturbation theory.",
        "positive": "Contribution of the charm quark to the \u0394I=1/2 rule: We report on the progress of our ongoing project to quantify the role of the\ncharm quark in the non-leptonic decay of a kaon into two pions. The effect of\nits associated mass scale in the dynamics underlying the \\Delta I = 1/2 rule\ncan be studied by monitoring the dependence of kaon decay amplitudes on the\ncharm quark mass using an effective \\Delta S = 1 weak Hamiltonian. In contrast\nto commonly used approaches the charm quark is kept as an active degree of\nfreedom. Quenched results in the GIM limit have shown that a significant part\nof the \\Delta I = 1/2 enhancement is purely due to low-energy QCD effects.\nMoving away from the GIM limit involves the computation of diagrams containing\nclosed quark loops which requires new variance reduction techniques in order to\ndetermine the relevant weak effective low-energy couplings. We employ a\ncombination of low-mode averaging and stochastic volume sources in order to\ncompute these diagrams and observe a significant improvement in the statistical\nsignal."
    },
    {
        "anchor": "Vortices and confinement: We review recent developments in the vortex picture of confinement. We\ndiscuss numerical simulations demonstrating that the entire asymptotic string\ntension is due to vortex-induced fluctuations of the Wilson loop. Analytical\nand numerical results concerning the presence of vortices as the necessary and\nsufficient condition for confinement at arbitrarily weak coupling in SU(N)\ngauge theories are also discussed.",
        "positive": "Composite electroweak sectors on the lattice: In the post-Higgs discovery era, the primary goal of the Large Hadron\ncollider is to discover new physics Beyond the Standard Model. One fundamental\nquestion is does new beyond the Standard Model composite dynamics provides the\norigin of the Higgs field and potential. After reviewing the main motivations\nto consider composite models based on a new strongly interacting sector, we\nsummarise the efforts of the lattice community to investigate the viability of\nmodels featuring a composite Higgs sector. We argue that first principle\ncalculations are necessary in view of the fast improvements in accuracy of\nexperimental measurements in the Higgs sector. We stress the importance for\nlattice calculations to provide a testing benchmark for non perturbative\nmechanisms. It is highlighted that the rich phenomenology of non-abelian gauge\ntheories raises a number of questions that can be explored using lattice\ncalculations. First principle results therefore provide crucial insights in the\ntheory landscape that could guide the next generation of Composite Higgs\nmodels."
    },
    {
        "anchor": "$K\\to\u03c0\u03c0$ matrix elements beyond the leading-order chiral expansion: We propose an approach for calculating $K\\to\\pi\\pi$ decays to the\nnext-to-leading order in chiral expansion. A detailed numerical study of this\napproach is being performed.",
        "positive": "Improvement via hypercubic smearing in triplet and sextet QCD: We study non-perturbative improvement in SU(3) lattice gauge theory coupled\nto fermions in the fundamental and two-index symmetric representations. Our\nlattice action is defined with hypercubic smeared links incorporated into the\nWilson-clover fermion kernel. Using standard Schroedinger-functional techniques\nwe estimate the clover coefficient Csw and find that discretization errors are\nmuch smaller than in thin-link theories."
    },
    {
        "anchor": "Continuum Determination of Light Quark Masses from Quenched Lattice QCD: We compute the strange and the average up/down quark masses in the quenched\napproximation of lattice QCD, by using the O(a)-improved Wilson action and\noperators and by implementing the non-perturbative renormalization. Our\ncomputation is performed at four values of the lattice spacing, from which we\ncould extrapolate to the continuum limit. Our final result for the strange\nquark mass (in the MSbar scheme) is ms(2 GeV) = (106 +/- 2 +/- 8) MeV. For the\naverage up/down quark mass we have ml(2 GeV) = (4.4 +/- 0.1 +/- 0.4) MeV. The\nratio ms/ml = (24.3 +/- 0.2 +/- 0.6).",
        "positive": "Gauss's Law, Duality, and the Hamiltonian Formulation of U(1) Lattice\n  Gauge Theory: Quantum computers have the potential to explore the vast Hilbert space of\nentangled states that play an important role in the behavior of strongly\ninteracting matter. This opportunity motivates reconsidering the Hamiltonian\nformulation of gauge theories, with a suitable truncation scheme to render the\nHilbert space finite-dimensional. Conventional formulations lead to a Hilbert\nspace largely spanned by unphysical states; given the current inability to\nperform large scale quantum computations, we examine here how one might\nrestrict wave function evolution entirely or mostly to the physical subspace.\nWe consider such constructions for the simplest of these theories containing\ndynamical gauge bosons -- U(1) lattice gauge theory without matter in $d=2,3$\nspatial dimensions -- and find that electric-magnetic duality naturally plays\nan important role. We conclude that this approach is likely to significantly\nreduce computational overhead in $d=2$ by a reduction of variables and by\nallowing one to regulate magnetic fluctuations instead of electric. The former\nadvantage does not exist in $d=3$, but the latter might be important for\nasymptotically-free gauge theories."
    },
    {
        "anchor": "Preserving gauge invariance in neural networks: In these proceedings we present lattice gauge equivariant convolutional\nneural networks (L-CNNs) which are able to process data from lattice gauge\ntheory simulations while exactly preserving gauge symmetry. We review aspects\nof the architecture and show how L-CNNs can represent a large class of gauge\ninvariant and equivariant functions on the lattice. We compare the performance\nof L-CNNs and non-equivariant networks using a non-linear regression problem\nand demonstrate how gauge invariance is broken for non-equivariant models.",
        "positive": "Machine Learning Estimators for Lattice QCD Observables: A novel technique using machine learning (ML) to reduce the computational\ncost of evaluating lattice quantum chromodynamics (QCD) observables is\npresented. The ML is trained on a subset of background gauge field\nconfigurations, called the labeled set, to predict an observable $O$ from the\nvalues of correlated, but less compute-intensive, observables $\\mathbf{X}$\ncalculated on the full sample. By using a second subset, also part of the\nlabeled set, we estimate the bias in the result predicted by the trained ML\nalgorithm. A reduction in the computational cost by about $7\\%-38\\%$ is\ndemonstrated for two different lattice QCD calculations using the Boosted\ndecision tree regression ML algorithm: (1) prediction of the nucleon\nthree-point correlation functions that yield isovector charges from the\ntwo-point correlation functions, and (2) prediction of the phase acquired by\nthe neutron mass when a small Charge-Parity (CP) violating interaction, the\nquark chromoelectric dipole moment interaction, is added to QCD, again from the\ntwo-point correlation functions calculated without CP violation."
    },
    {
        "anchor": "A Geometrical Interpretation of Hyperscaling Breaking in the Ising Model: In random percolation one finds that the mean field regime above the upper\ncritical dimension can simply be explained through the coexistence of infinite\npercolating clusters at the critical point. Because of the mapping between\npercolation and critical behaviour in the Ising model, one might check whether\nthe breakdown of hyperscaling in the Ising model can also be intepreted as due\nto an infinite multiplicity of percolating Fortuin-Kasteleyn clusters at the\ncritical temperature T_c. Preliminary results suggest that the scenario is much\nmore involved than expected due to the fact that the percolation variables\nbehave differently on the two sides of T_c.",
        "positive": "High-precision calculation of the strange nucleon electromagnetic form\n  factors: We report a direct lattice QCD calculation of the strange nucleon\nelectromagnetic form factors $G_E^s$ and $G_M^s$ in the kinematic range $0 \\leq\nQ^2 \\lesssim 1.2\\: {\\rm GeV}^2$. For the first time, both $G_E^s$ and $G_M^s$\nare shown to be nonzero with high significance. This work uses\ncloser-to-physical lattice parameters than previous calculations, and achieves\nan unprecedented statistical precision by implementing a recently proposed\nvariance reduction technique called hierarchical probing. We perform\nmodel-independent fits of the form factor shapes using the $z$-expansion and\ndetermine the strange electric and magnetic radii and magnetic moment. We\ncompare our results to parity-violating electron-proton scattering data and to\nother theoretical studies."
    },
    {
        "anchor": "A Lattice Formulation of Two Dimensional Topological Field Theory: We propose a non-perturbative criterion to investigate whether supersymmetric\nlattice gauge theories preserving partial SUSY can have the desired continuum\nlimit or not. Since the target continuum theories of the lattice models are\nextended supersymmetric gauge theories including the topological field theory\n(TFT) as a special subsector, the continuum limits of them should reproduce the\nproperties of the TFT. Therefore, whether the property of the TFT can be\nrecovered at the continuum limit becomes a non-perturbative criterion. Then we\naccept it as a criterion. In this paper, among the topological properties, we\ninvestigate the BRST cohomology on the two dimensional ${\\mathcal N}=(4,4)$\nCKKU lattice model without moduli fixing mass term. We show that the BRST\ncohomology in the target continuum theory cannot be realized from the BRST\ncohomology on the lattice. From this result, we obtain the possible implication\nthat the ${\\mathcal N} = (4,4)$ CKKU model cannot recover the target continuum\ntheory if the non-perturbative effects are taken into account.",
        "positive": "Geometrical Origin of Tricritical Points of various U(1) Lattice Models: We review the dual relationship between various compact U(1) lattice models\nand Abelian Higgs models, the latter being the disorder field theories of\nline-like topological excitations in the systems. We point out that the\npredicted first-order transitions in the Abelian Higgs models (Coleman-Weinberg\nmechanism) are, in three dimensions, in contradiction with direct numerical\ninvestigations in the compact U(1) formulation since these yield continuous\ntransitions in the major part of the phase diagram. In four dimensions, there\nare indications from Monte Carlo data for a similar situation. Concentrating on\nthe strong-coupling expansion in terms of geometrical objects, surfaces or\nlines, with certain statistical weights, we present semi-quantitative arguments\nexplaining the observed cross-over from first-order to continuous transitions\nby the balance between the lowest two weights (``2:1 ratio'') of these\ngeometrical objects."
    },
    {
        "anchor": "$D_s \\rightarrow \u03b7, \u03b7'$ semileptonic decay form factors with\n  disconnected quark loop contributions: We calculate for the first time the form factors of the semi-leptonic decays\nof the $D_s$ meson to $\\eta$ and $\\eta^\\prime$ using lattice techniques. As a\nby-product of the calculation we obtain the masses and leading distribution\namplitudes of the $\\eta$ and $\\eta^\\prime$ mesons. We use $N_f=2+1$\nnon-perturbatively improved clover fermions on configurations with a lattice\nspacing $a\\sim 0.075$ fm. We are able to obtain clear signals for relevant\nmatrix elements, using several noise reduction techniques, both for the\nconnected and disconnected contributions. This includes a new method for\nreducing the variance of pseudoscalar disconnected two-point functions. At zero\nmomentum transfer, we obtain for the scalar form factors, $|f_0^{D_s\\to\n\\eta}|=0.564(11)$ and $|f_0^{D_s\\to \\eta'}|=0.437(18)$ at $M_\\pi\\approx 470\\,\n{\\rm MeV}$, as well as $|f_0^{D_s\\to \\eta}|=0.542(13)$ and $|f_0^{D_s\\to\n\\eta'}|=0.404(25)$ at $M_\\pi\\approx 370\\, {\\rm MeV}$, where the errors are\nstatistical only.",
        "positive": "Spectral sum for the color-Coulomb potential in SU(3) Coulomb gauge\n  lattice Yang-Mills theory: We discuss the essential role of the low-lying eigenmodes of the\nFaddeev-Popov (FP) ghost operator on the confining color-Coulomb potential\nusing SU(3) quenched lattice simulations in the Coulomb gauge. The\ncolor-Coulomb potential is expressed as a spectral sum of the FP ghost operator\nand has been explored by partially summing the FP eigenmodes. We take into\naccount the Gribov copy effects that have a great impact on the FP eigenvalues\nand the color-Coulomb potential. We observe that the lowest eigenvalue vanishes\nin the thermodynamic limit much faster than that in the Landau gauge. The\ncolor-Coulomb potential at large distances is governed by the near-zero FP\neigenmodes; in particular, the lowest one accounts for a substantial portion of\nthe color-Coulomb string tension comparable to the Wilson string tension."
    },
    {
        "anchor": "Analytical and Numerical Study of the Aharonov--Bohm Effect in 3D and 4D\n  Abelian Higgs Model: We discuss the Aharonov--Bohm effect in three and four dimensional\nnon--compact lattice Abelian Higgs model. We show analytically that this effect\nleads to the long--range Coulomb interaction of the charged particles, which is\nconfining in three dimensions. The Aharonov--Bohm effect is found in numerical\ncalculations in 3D Abelian Higgs model.",
        "positive": "D and D_s meson spectroscopy: Results are presented for the low-lying spectrum of D and D_s mesons\ncalculated in lattice QCD using 2+1 flavor Clover-Wilson configurations made\navailable by the PACS-CS collaboration. For the heavy quark, the Fermilab\nmethod is employed. The main focus is S- and P-wave states of charmed and\ncharmed-strange mesons, where previous lattice QCD results have been mostly\nfrom quenched calculations. In addition to the ground states, some excited\nstates are extracted. To check the method, calculations of the charmonium\nspectrum are also carried out. For charmonium, the low-lying spectrum agrees\nfavorably with experiment. For heavy-strange and heavy-light systems\nsubstantial differences in comparison to experiment values remain for some\nstates."
    },
    {
        "anchor": "Re $A_0$ and Re $A_2$ from Quenched Lattice QCD: We have used domain wall fermions to calculate $K \\to \\pi$ and $K \\to 0$\nmatrix elements which can be used to study the $\\Delta I = 1/2$ rule for K\ndecays in the Standard Model. Nonlinearities in the $\\Delta I = 3/2$ matrix\nelements due to chiral logarithms are explored and the subtractions needed for\nthe $\\Delta I = 1/2$ matrix elements are discussed. Using renormalization\nfactors calculated using non-perturbative renormalization then yields values\nfor real $A_0$ and $A_2$. We present the details of our quenched $16^3 \\times\n32 \\times 16$, $\\beta = 6.0$, $M_5 = 1.8$ simulation, where a previous\ncalculation showed that the finite $L_s$ chiral symmetry breaking effects are\nsmall ($m_{\\rm res} \\approx 4 \\rm MeV$).",
        "positive": "The perturbative SU(N) one-loop running coupling in the twisted gradient\n  flow scheme: We report on our computation of the perturbative running of the 't Hooft\ncoupling in a pure gauge $SU(N)$ theory with twisted boundary conditions. The\ncoupling is defined in terms of the energy density of the flow fields at a\nscale given by a particular combination of the linear size of the torus and the\nrank of the gauge group. We present our results for the matching at one-loop\norder to the $\\bar{MS}$ scheme in the case of a two-dimensional non-trivial\ntwist. The ratio of $\\Lambda$ parameters is determined for the case of $SU(3)$\nand for various other values of the number of colours and several choices of\nthe magnetic flux induced by the twist."
    },
    {
        "anchor": "f_B and two scales problems in lattice QCD: A novel method to calculate f_B on the lattice is introduced, based on the\nstudy of the dependence of finite size effects upon the heavy quark mass of\nflavoured mesons and on a non-perturbative recursive finite size technique. We\navoid the systematic errors related to extrapolations from the static limit or\nto the tuning of the coefficients of effective Lagrangian and the results admit\nan extrapolation to the continuum limit. We perform a first estimate at finite\nlattice spacing, but close to the continuum limit, giving f_B = 170(11)(5)(22)\nMeV. We also obtain f_{B_s} = 192(9)(5)(24) MeV. The first error is\nstatistical, the second is our estimate of the systematic error from the method\nand the third the systematic error from the specific approximations adopted in\nthis first exploratory calculation. The method can be generalized to two--scale\nproblems in lattice QCD.",
        "positive": "Overlap Hypercube Fermions in QCD: We present simulation results obtained with overlap hypercube fermions in QCD\nnear the chiral limit. We relate our results to chiral perturbation theory in\nboth, the epsilon-regime and in the p-regime. In particular we measured the\npion decay constant by different methods, as well as the chiral condensate,\nlight meson masses, the PCAC quark mass and the renormalisation constant Z_A."
    },
    {
        "anchor": "A precise determination of T_c in QCD from scaling: Existing lattice data on the QCD phase transition are analyzed in\nrenormalized perturbation theory. In quenched QCD it is found that T_c scales\nfor lattices with only 3 time slices, and that T_c/Lambda_msbar=1.15 \\pm 0.05.\nA preliminary estimate in QCD with two flavours of dynamical quarks shows that\nthis ratio depends on the quark mass. For realistic quark masses we estimate\nT_c/Lambda_msbar=0.49 \\pm 0.02. We also investigate the equation of state in\nquenched QCD at 1-loop order in renormalised perturbation theory.",
        "positive": "The spectrum of screening masses near T_c: predictions from universality: We discuss the spectrum of screening masses in a pure gauge theory near the\ndeconfinement temperature from the point of view of the dimensionally reduced\nmodel describing the spontaneous breaking of the center symmetry. Universality\narguments can be used to predict the values of the mass ratios in the scaling\nregion of the deconfined phase when the transition is of second order. One such\nprediction is that the scalar sector of the screening spectrum in SU(2) pure\ngauge theory contains a bound state of the fundamental excitation,\ncorresponding through universality to the bound state found in the 3D Ising\nmodel and phi^4 theory in the broken symmetry phase. A Monte Carlo evaluation\nof the screening masses in the gauge theory confirms the validity of the\nprediction. We briefly discuss the possibility of using similar arguments for\nfirst order deconfinement transitions, and in particular for the physically\nrelevant case of SU(3)."
    },
    {
        "anchor": "Study of lattice QCD at finite chemical potential using canonical\n  ensemble approach: New approach to computation of canonical partition functions in $N_f=2$\nlattice QCD is presented. We compare results obtained by new method with\nresults obtained by known method of hopping parameter expansion. We observe\nagreement between two methods indicating validity of the new method. We use\nresults for the number density obtained in the confining and deconfining phases\nat imaginary chemical potential to determine the phase transition line at real\nchemical potential.",
        "positive": "The Vacuum Polarization: Power Corrections beyond OPE ?: We compute the vacuum polarization on the lattice using non-perturbatively\nO(a) improved Wilson fermions. The result is compared with the operator product\nexpansion (OPE)."
    },
    {
        "anchor": "A Dual Non-abelian Yang-Mills Amplitude in Four Dimensions: We derive an explicit formula for the vertex amplitude of dual SU(2)\nYang-Mills theory in four dimensions on the lattice, and provide an efficient\nalgorithm (of order j to the fourth power) for its computation. This opens the\nway for both numerical and analytic development of dual methods, previously\nlimited to the case of three dimensions.",
        "positive": "Exact Chiral Fermions and Finite Density on Lattice: Any mu^2-divergence is shown analytically to be absent for a class of actions\nfor Overlap and Domain Wall Fermions with nonzero chemical potential. All such\nactions are, however, shown to violate the chiral invariance. While the\nparameter M of these actions can be shown to be irrelevant in the continuum\nlimit, as expected, it is shown numerically that the continuum limit can be\nreached with relatively coarser lattices for M in the range of 1.5-1.6."
    },
    {
        "anchor": "Exotic hybrid mesons with light quarks: Hybrid mesons, made from a quark, an antiquark and gluons, can have quantum\nnumbers inaccessible to conventional quark-antiquark states. Confirmation of\nsuch states would give information on the role of \"dynamical\" color in low\nenergy QCD. We present preliminary results for hybrid meson masses using light\nWilson valence quarks.",
        "positive": "Thermal momentum distribution from shifted boundary conditions: At finite temperature the distribution of the total momentum is an observable\ncharacterizing the thermal state of a field theory, and its cumulants are\nrelated to thermodynamic potentials. In a relativistic system at zero chemical\npotential, for instance, the thermal variance of the total momentum is a direct\nmeasure of the entropy. We relate the generating function of the cumulants to\nthe ratio of a path integral with properly shifted boundary conditions in the\ncompact direction over the ordinary partition function. In this form it is well\nsuited for Monte-Carlo evaluation, and the cumulants can be extracted\nstraightforwardly. We test the method in the SU(3) Yang--Mills theory, and\nobtain the entropy density at three different temperatures."
    },
    {
        "anchor": "Quark mass dependence of pseudoscalar masses and decay constants on a\n  lattice: Our previous calculations of the sea- and valence-quark mass dependence of\nthe pseudoscalar meson masses and decay constants is repeated on a 16^3x32\nlattice which allows for a better determination of the quantities in question.\n  The conclusions are similar as before on the 16^4 lattice [1].\n  The two light dynamical quark flavours we simulate have masses in the range\n1/4 m_s < m_{u,d} < 2/3 m_s.\n  The sea quark mass dependence of f_pi and m_pi^2/m_q is well described by the\nnext-to-leading order (NLO) Chiral Perturbation Theory (ChPT) formulas and\nclearly shows the presence of chiral logarithms.\n  The valence quark mass dependence requires the presence of NNLO contributions\nin Partially Quenched ChPT (PQChPT) -- in addition to the NLO terms.\n  The O(a) lattice artifacts in these quantities turn out to be small.",
        "positive": "Wilson Fermions on a Randomly Triangulated Manifold: A general method of constructing the Dirac operator for a randomly\ntriangulated manifold is proposed. The fermion field and the spin connection\nlive, respectively, on the nodes and on the links of the corresponding dual\ngraph. The construction is carried out explicitly in 2-d, on an arbitrary\norientable manifold without boundary. It can be easily converted into a\ncomputer code. The equivalence, on a sphere, of Majorana fermions and Ising\nspins in 2-d is rederived. The method can, in principle, be extended to higher\ndimensions."
    },
    {
        "anchor": "Light hadron spectroscopy using domain wall valence quarks on an Asqtad\n  sea: We calculate the light hadron spectrum in full QCD using two plus one flavor\nAsqtad sea quarks and domain wall valence quarks. Meson and baryon masses are\ncalculated on a lattice of spatial size $L \\approx 2.5$\\texttt{fm}, and a\nlattice spacing of $a \\approx 0.124$\\texttt{fm}, for pion masses as light as\n$m_\\pi \\approx 300$\\texttt{MeV}, and compared with the results by the MILC\ncollaboration with Asqtad valence quarks at the same lattice spacing. Two- and\nthree-flavor chiral extrapolations of the baryon masses are performed using\nboth continuum and mixed-action heavy baryon chiral perturbation theory. Both\nthe three-flavor and two-flavor functional forms describe our lattice results,\nalthough the low-energy constants from the next-to-leading order SU(3) fits are\ninconsistent with their phenomenological values. Next-to-next-to-leading order\nSU(2) continuum formulae provide a good fit to the data and yield and\nextrapolated nucleon mass consistent with experiment, but the convergence\npattern indicates that even our lightest pion mass may be at the upper end of\nthe chiral regime. Surprisingly, our nucleon masses are essentially lineaer in\n$m_\\pi$ over our full range of pion masses, and we show this feature is common\nto all recent dynamical calculations of the nucleon mass. The origin of this\nlinearity is not presently understood, and lighter pion masses and increased\ncontrol of systematic errors will be needed to resolve this puzzling behavior.",
        "positive": "Thermodynamic Properties of Strongly Interacting Matter at Non-zero\n  Baryon Number Density: We present recent lattice results on QCD thermodynamics at non-vanishing\nbaryon number density obtained from a 6th order Taylor expansion in the\nchemical potential. Results for bulk thermodynamic observables, in particular\nfor fluctuations in the baryon number density, are found to be well described\nby a hadron resonance gas model at low temperature and an ideal quark gluon gas\nat high temperature. We also analyze the radius of convergence of the Taylor\nseries and discuss the information it provides on the occurrence of a second\norder phase transition point in the QCD phase diagram."
    },
    {
        "anchor": "Quantum Many-Body Scars for Arbitrary Integer Spin in $2+1$D~Abelian\n  Gauge Theories: The existence of Quantum Many-Body Scars, high-energy eigenstates that evade\nthe Eigenstate Thermalization Hypothesis, has been established across different\nquantum many-body systems, including gauge theories corresponding to spin-1/2\nQuantum Link Models. We systematically identify scars for pure gauge theories\nwith arbitrarily large integer spin $S$ in $2+1$D, concretely for Truncated\nLink Models, where the electric field is restricted to $2S+1$ states per link.\nThrough an explicit analytic construction, we show that the presence of scars\nis widespread in $2+1$D gauge theories for arbitrary integer spin. We confirm\nthese findings numerically for small truncated spin and $S=1$ Quantum Link\nModels. The proposed analytic construction establishes the presence of scars\nfar beyond volumes and spins that can be probed with existing numerical\nmethods.",
        "positive": "$\u03be/\u03be_{2nd}$ ratio as a tool to refine Effective Polyakov Loop models: Effective Polyakov line actions are a powerful tool to study the finite\ntemperature behaviour of lattice gauge theories. They are much simpler to\nsimulate than the original lattice model and are affected by a milder sign\nproblem, but it is not clear to which extent they really capture the rich\nspectrum of the original theories. We propose here a simple way to address this\nissue based on the so called second moment correlation length $\\xi_{2nd}$. The\nratio $\\xi/\\xi_{2nd}$ between the exponential correlation length and the second\nmoment one is equal to 1 if only a single mass is present in the spectrum, and\nit becomes larger and larger as the complexity of the spectrum increases. Since\nboth $\\xi$ and $\\xi_{2nd}$ are easy to measure on the lattice, this is a cheap\nand efficient way to keep track of the spectrum of the theory. As an example of\nthe information one can obtain with this tool we study the behaviour of\n$\\xi/\\xi_{2nd}$ in the confining phase of the ($D=3+1$) $\\mathrm{SU}(2)$ gauge\ntheory and show that it is compatible with 1 near the deconfinement transition,\nbut it increases dramatically as the temperature decreases. We also show that\nthis increase can be well understood in the framework of an effective string\ndescription of the Polyakov loop correlator. This non-trivial behaviour should\nbe reproduced by the Polyakov loop effective action; thus, it represents a\nstringent and challenging test of existing proposals and it may be used to\nfine-tune the couplings and to identify the range of validity of the\napproximations involved in their construction."
    },
    {
        "anchor": "Extracting the effective Polyakov line action from SU(2) and SU(3)\n  lattice gauge theories: We describe the \"relative weights\" method used to compute the effective\nPolyakov line action corresponding to a given lattice gauge theory, and present\nsome results that have been obtained so far. The main motivation is the sign\nproblem, which may be easier to address in the effective theory than in the\nunderlying gauge theory.",
        "positive": "Further studies of QCD with sextet quarks: We continue our simulations of QCD with 2 flavours of colour-sextet quarks as\na model for walking technicolor. QCD with 3 flavours of colour-sextet quarks is\nalso studied for comparison with the 2-flavour theory. We simulate these\ntheories at finite temperatures T, using lattices with a finite extent $N_t\na=1/T$ in the (Euclidean) time direction. The lattice coupling at the\nchiral-symmetry-restoration transition is measured as a function of $N_t$. If\nthis is indeed a finite-temperature transition, the evolution of this coupling\nwith $N_t$ as $N_t \\rightarrow \\infty$ and hence the lattice spacing $a\n\\rightarrow 0$ should be described by asymptotic freedom. If so, the theory is\nQCD-like and walking. If, however, this coupling approaches a constant non-zero\nvalue in the large $N_t$ limit, the transition is a bulk transition and the\ncontinuum theory is conformal. For the 2-flavour theory, the coupling does show\na significant decrease between $N_t=8$ and $N_t=12$, favouring the walking\nscenario. However, preliminary results are that the change is less than that\npredicted by asymptotic freedom. For the 3-flavour case, which is expected to\nbe conformal, there is still a significant decrease in the coupling between\n$N_t=6$ and $N_t=8$, indicating that we are not yet at large enough $N_t$."
    },
    {
        "anchor": "Phase Structure and Critical Behavior of Multi-Higgs U(1) Lattice Gauge\n  Theory in Three Dimensions: We study the three-dimensional (3D) compact U(1) lattice gauge theory coupled\nwith $N$-flavor Higgs fields by means of the Monte Carlo simulations. This\nmodel is relevant to multi-component superconductors, antiferromagnetic spin\nsystems in easy plane, inflational cosmology, etc. It is known that there is no\nphase transition in the N=1 model. For N=2, we found that the system has a\nsecond-order phase transition line $\\tilde{c}_1(c_2)$ in the $c_2$(gauge\ncoupling)$-c_1$(Higgs coupling) plane, which separates the confinement phase\nand the Higgs phase. Numerical results suggest that the phase transition\nbelongs to the universality class of the 3D XY model as the previous works by\nBabaev et al. and Smiseth et al. suggested. For N=3, we found that there exists\na critical line similar to that in the N=2 model, but the critical line is\nseparated into two parts; one for $c_2 < c_{2{\\rm tc}}=2.4\\pm 0.1$ with\nfirst-order transitions, and the other for $ c_{2{\\rm tc}} < c_2$ with\nsecond-order transitions, indicating the existence of a tricritical point. We\nverified that similar phase diagram appears for the N=4 and N=5 systems. We\nalso studied the case of anistropic Higgs coupling in the N=3 model and found\nthat there appear two second-order phase transitions or a single second-order\ntransition and a crossover depending on the values of the anisotropic Higgs\ncouplings. This result indicates that an \"enhancement\" of phase transition\noccurs when multiple phase transitions coincide at a certain point in the\nparameter space.",
        "positive": "Adjoint 2D QCD and Pure 3D QCD: A Comparison of Spectra: We briefly review the 1+1-dimensional SU(N) gauge theory minimally coupled to\nan adjoint scalar, based upon a dimensional reduction of 2+1-dimensional pure\ngauge theory, which approximates the dynamics of the transversely polarized\ngluon. The lightest glueball states are investigated non-perturbatively using\nlight-front quantisation in the large-N limit a la 't Hooft, and the physical\nmeaning of the results elucidated. Comparison is made with recent lattice Monte\nCarlo data for 3-dimensional quenched QCD."
    },
    {
        "anchor": "Monte Carlo Simulation of the Three Dimensional Thirring Model: We study the Thirring model in three spacetime dimensions, by means of Monte\nCarlo simulation on lattice sizes 8^3 and 12^3, for numbers of fermion flavors\nN_f=2,4,6. For sufficiently strong interaction strength, we find that\nspontaneous chiral symmetry breaking occurs for N_f=2,4, in accordance with the\npredictions of the Schwinger-Dyson approach. The phase transitions which occur\nare continuous and with critical scaling behaviour depending on N_f. For N_f=6\nour results are preliminary, and no firm conclusions about the existence or\notherwise of chiral symmetry breaking are possible",
        "positive": "Strange and charm baryon masses with two flavors of dynamical twisted\n  mass fermions: The masses of the low-lying strange and charm baryons are evaluated using two\ndegenerate flavors of twisted mass sea quarks for pion masses in the range of\nabout 260 MeV to 450 MeV. The strange and charm valence quark masses are tuned\nto reproduce the mass of the kaon and D-meson at the physical point. The\ntree-level Symanzik improved gauge action is employed. We use three values of\nthe lattice spacing, corresponding to $\\beta=3.9$, $\\beta=4.05$ and $\\beta=4.2$\nwith $r_0/a=5.22(2)$, $r_0/a=6.61(3)$ and $r_0/a=8.31(5)$ respectively.\n%spacings $a=0.0855(5)$ and $a=0.0667(3)$ determined from the pion decay\nconstant. We examine the dependence of the strange and charm baryons on the\nlattice spacing and strange and charm quark masses. The pion mass dependence is\nstudied and physical results are obtained using heavy baryon chiral\nperturbation theory to extrapolate to the physical point."
    },
    {
        "anchor": "One-Flavour Hybrid Monte Carlo with Wilson Fermions: The Wilson fermion determinant can be written as product of the determinants\nof two hermitian positive definite matrices. This formulation allows to\nsimulate non-degenerate quark flavors by means of the hybrid Monte Carlo\nalgorithm. A major numerical difficulty is the occurrence of nested inversions.\nWe construct a Uzawa iteration scheme which treats the nested system within one\niterative process.",
        "positive": "Kinetic Factors in Affine Quantization and Their Role in Field Theory\n  Monte Carlo: Affine quantization, which is a parallel procedure with canonical\nquantization, needs to use its principal quantum operators, most simply\n$D=(PQ+QP)/2$ and $Q\\neq0$, to represent appropriate kinetic factors, normally\n$P^2$, which involve only one canonical quantum operator. The need for this\nrequirement stems from the quantization of selected problems that require\naffine quantization to achieve valid Monte Carlo results. This task is resolved\nfor introductory examples as well as examples that involve scalar quantum field\ntheories."
    },
    {
        "anchor": "Excited and exotic bottomonium spectroscopy from lattice QCD: We explore the spectrum of excited and exotic bottomonia using lattice QCD.\nHighly excited states are identified with masses up to 11,000 MeV, many of\nwhich can be grouped into supermultiplets matching those of the quark model\nwhile exotic spin--parity--charge-conjugation quantum numbers\n$J^{PC}=0^{+-},\\,1^{-+},\\,2^{+-}$ that cannot be formed from $\\bar{q}q$ alone\nare also identified. Single-meson operator constructions are used that have\ngood $J^{PC}$ in the continuum, these are found to overlap well onto heavy\nquark states with $J\\le4$. A continuum $J^{PC}$ is assigned to each level,\nbased on the distribution amongst lattice irreps and dominant operator\noverlaps. States with a dominant gluonic component are identified and form a\nhybrid supermultiplet with $J^{PC}=(0,1,2)^{-+},\\, 1^{--}$, approximately 1500\nMeV above the ground-state $\\eta_b$, similar to previous computations with\nlight, strange and charm quark systems.",
        "positive": "Noncompact, Gauge-Invariant Simulations of U(1), SU(2), and SU(3): We have applied a new noncompact, gauge-invariant, Monte Carlo method to\nsimulate the U(1), SU(2), and SU(3) gauge theories on 8^4 and 12^4 lattices.\nFor U(1) the Creutz ratios of the Wilson loops agree with the exact results for\nbeta > 0.5 after a renormalization of the charge. The SU(2) and SU(3) Creutz\nratios robustly display quark confinement at beta = 0.5 and beta = 2,\nrespectively. At much weaker coupling, the SU(2) and SU(3) Creutz ratios agree\nwith perturbation theory after a renormalization of the coupling constant. For\nSU(3) without quarks, our lattice QCD parameter is Lambda_L = 130 +- 18$ MeV."
    },
    {
        "anchor": "Confinement from semiclassical gluon fields in SU(2) gauge theory: The infrared structure of SU(2) Yang-Mills theory is studied by means of\nlattice gauge simulations using a new constrained cooling technique. This\nmethod reduces the action while all Polyakov lines on the lattice remain\nunchanged. In contrast to unconstrained cooling, quark confinement is still\nintact. A study of the Hessian of the Yang-Mills action shows that low action\n(semi-) classical configurations can be achieved, with a characteristic\nsplitting between collective modes and higher momentum modes. Besides\nconfinement, the semiclassical configurations also support the topological\nsusceptibility and generate spontaneous breakdown of chiral symmetry.We show\nthat they possess a cluster structure of locally mainly (anti-) selfdual\nobjects. By contrast to an instanton or a meron medium, the topological charge\nof individual clusters is smoothly distributed.",
        "positive": "Light-cone distribution amplitudes of octet baryons from lattice QCD: We present lattice QCD results for the wave function normalization constants\nand the first moments of the distribution amplitudes for the lowest-lying\nbaryon octet. The analysis is based on a large number of $N_f=2+1$ ensembles\ncomprising multiple trajectories in the quark mass plane including physical\npion (and kaon) masses, large volumes, and, most importantly, five different\nlattice spacings down to $a=0.039\\,\\mathrm{fm}$. This allows us to perform a\ncontrolled extrapolation to the continuum and infinite volume limits by a\nsimultaneous fit to all available data. We demonstrate that the formerly\nobserved violation of flavor symmetry breaking constraints can, indeed, be\nattributed to discretization effects that vanish in the continuum limit."
    },
    {
        "anchor": "Gauge-invariant scalar and field strength correlators in 3d: Gauge-invariant non-local scalar and field strength operators have been\nargued to have significance, e.g., as a way to determine the behaviour of the\nscreened static potential at large distances, as order parameters for\nconfinement, as input parameters in models of confinement, and as\ngauge-invariant definitions of light constituent masses in bound state systems.\nWe measure such \"correlators\" in the 3d pure SU(2) and SU(2)+Higgs models on\nthe lattice. We extract the corresponding mass parameters and discuss their\nscaling and physical interpretation. We find that the finite part of the MS-bar\nscheme mass measured from the field strength correlator is large, more than\nhalf the glueball mass. We also determine the non-perturbative contribution to\nthe Debye mass in the 4d finite T SU(2) gauge theory with a method due to\nArnold and Yaffe, finding $\\delta m_D\\approx 1.06(4)g^2T$.",
        "positive": "Renormalising vector currents in lattice QCD using momentum-subtraction\n  schemes: We examine the renormalisation of flavour-diagonal vector currents in lattice\nQCD with the aim of understanding and quantifying the systematic errors from\nnonperturbative artefacts associated with the use of intermediate\nmomentum-subtraction schemes. Our study uses the Highly Improved Staggered\nQuark (HISQ) action on gluon field configurations that include $n_f=2+1+1$\nflavours of sea quarks, but our results have applicability to other quark\nactions. Renormalisation schemes that make use of the exact lattice vector\nWard-Takahashi identity for the conserved current also have renormalisation\nfactors, $Z_V$, for nonconserved vector currents that are free of contamination\nby nonperturbative condensates. We show this by explicit comparison of two such\nschemes: that of the vector form factor at zero momentum transfer and the\nRI-SMOM momentum-subtraction scheme. The two determinations of $Z_V$ differ\nonly by discretisation effects (for any value of momentum-transfer in the\nRI-SMOM case). The RI$^{\\prime}$-MOM scheme, although widely used, does not\nshare this property. We show that $Z_V$ determined in the standard way in this\nscheme has $\\mathcal{O}(1\\%)$ nonperturbative contamination that limits its\naccuracy. Instead we define an RI$^{\\prime}$-MOM $Z_V$ from a ratio of local to\nconserved vector current vertex functions and show that this $Z_V$ is a safe\none to use in lattice QCD calculations. We also perform a first study of vector\ncurrent renormalisation with the inclusion of quenched QED effects on the\nlattice using the RI-SMOM scheme."
    },
    {
        "anchor": "Precision bottomonium properties and b quark mass from lattice QCD: As tests of QCD in the bottomonium system, we give the most accurate results\nto date for the ground-state hyperfine splitting and the $\\Upsilon$ leptonic\nwidth from full lattice QCD. These quantities are both accurately known from\nexperiment, so can provide a good test of $b$ physics, but previous lattice\nresults have been rather imprecise. We also test the impact on these quantities\nof the $b$ quark's electric charge. Our results are: $M_{\\Upsilon}-M_{\\eta_b} =\n$ 57.5(2.3)(1.0) MeV (where the second uncertainty comes from neglect of\nquark-line disconnected correlation functions) and decay constants, $f_{\\eta_b}\n=$ 724(12) MeV and $f_{\\Upsilon} =$ 677.2(9.7) MeV, giving $\\Gamma(\\Upsilon\n\\rightarrow e^+e^-) =$ 1.292(37)(3) keV. We also give a new determination of\nthe ratio of the masses for $b$ and $c$ quarks that is completely\nnonperturbative in lattice QCD and includes the calculation of QED effects for\nthe first time. This gives a result for the $b$ quark mass of\n$\\overline{m}_b(\\overline{m}_b,n_f=5) =$ 4.202(21) GeV.",
        "positive": "A classification of 2-dim Lattice Theory: A unified classification and analysis is presented of two dimensional Dirac\noperators of QCD-like theories in the continuum as well as in a naive lattice\ndiscretization. Thereby we consider the quenched theory in the strong coupling\nlimit. We do not only consider the case of a lattice which has an even number\nof lattice sites in both directions and is thus equivalent to the case of\nstaggered fermions. We also study lattices with one or both directions with an\nodd parity to understand the general mechanism of changing the universality\nclass via a discretization. Furthermore we identify the corresponding random\nmatrix ensembles sharing the global symmetries of these QCD-like theories.\nDespite the Mermin-Wagner-Coleman theorem we find good agreement of lattice\ndata with our random matrix predictions."
    },
    {
        "anchor": "A chiralspin symmetry in QCD in Minkowski space-time: In this paper, we look how to construct in Minkowski space-time a new type of\n\\textit{chiralspin} group transformation of the spinor fields, similar to the\none discovered by recent works of \\textit{Glozman et al.} in the context of\nhigh temperature QCD and truncated studies in lattice calculations. Afterwards,\nwe prove the invariance of free massless fermionic action under such group\ntransformations, as well the invariance of the Hamiltonian of free massless\nfermions. At the end, the possible presence of a symmetry driven by such new\n\\textit{chiralspin} group at high temperature QCD, also at non zero chemical\npotential, is discussed.",
        "positive": "The self-dual gauge fields and the domain wall fermion zero modes: A new type of gauge fixing of the Coulomb gauge domain wall fermion system\nthat reduces the fluctuation of the effective running coupling and the\neffective mass of arbitrary momentum direction including the region outside the\ncylinder cut region is proposed and tested in the $16^3\\times 32\\times 16$\ngauge configurations of RBC/UKQCD collaboration.\n  The running coupling at the lowest momentum point does not show infrared\nsuppression and compatible with the experimental data extracted from the JLab\ncollaboration. The source of the fluctuation of the effective mass near\nmomentum $p=$0.6GeV region is expected to be due to the domain wall fermion\nzero modes."
    },
    {
        "anchor": "Chiral symmetry breaking in lattice QED model with fermion brane: We propose a novel approach to the Graphene system using a local field theory\nof 4 dimensional QED model coupled to 2+1 dimensional Dirac fermions, whose\nvelocity is much smaller than the speed of light. Performing hybrid Monte Carlo\nsimulations of this model on the lattice, we compute the chiral condensate and\nits susceptibility with different coupling constant, velocity parameter and\nflavor number. We find that the chiral symmetry is dynamically broken in the\nsmall velocity regime and obtain a qualitatively consistent behavior with the\nprediction from Schwinger-Dyson equations.",
        "positive": "Instanton size distributions from calibrated cooling: Using an under-relaxed cooling algorithm we investigated the vacuum in the\n$2d\\ O(3)$ model and $4d$ pure gauge $SU(2)$. We calibrated the amount of\ncooling performed to have similar physical effect at different lattice\nspacings."
    },
    {
        "anchor": "On the topological structure of the QCD vacuum: A review of results from lattice studies using improved and scale controlled\ncooling methods is presented and their significance is discussed. The\nimprovement of the action ensures stable instanton solutions of physical sizes.\nThe scale controlled cooling can be generally used as a gauge invariant low\npass filter to extract the physics from noisy MC configurations; in particular\nit preserves instanton-antiinstanton pairs selected according to their\ninteraction. We apply these methods to analyze various features of the\ntopological structure of the Yang-Mills vacuum in a scaling invariant way.",
        "positive": "Dynamical lattice QCD thermodynamics and the U(1)_A symmetry with domain\n  wall fermions: Results from numerical simulations of full, two flavor QCD thermodynamics at\nN_t=4 with domain wall fermions are presented. For the first time a numerical\nsimulation of the full QCD phase transition displays a low temperature phase\nwith spontaneous chiral symmetry breaking but intact flavor symmetry and a high\ntemperature phase with the full $SU(2) \\times SU(2)$ chiral flavor symmetry. It\nis found that close to the transition in the high temperature phase the U(1)_A\naxial symmetry is broken only by a small amount. This result is of particular\ninterest because of the connection between U(1)_A symmetry breaking and the\nexpected order of the transition."
    },
    {
        "anchor": "Baryons in Partially Quenched Chiral Perturbation Theory: We include the lowest-lying octet- and decuplet-baryons into partially\nquenched chiral perturbation theory. Perturbing about the chiral limit of the\ngraded SU(6|3)_L x SU(6|3)_R flavor group of partially quenched QCD, we compute\nthe leading one-loop contributions to the octet-baryon masses, magnetic moments\nand matrix elements of isovector twist-2 operators. We work in the isospin\nlimit and keep two of the three sea quarks degenerate. The usefulness of the\nnon-unique extension of the electric charge matrix and the isovector twist-2\noperators from QCD to partially quenched QCD is discussed.",
        "positive": "An Alternative Lattice Field Theory Formulation Inspired by Lattice\n  Supersymmetry -Summary of the Formulation-: We propose a lattice field theory formulation which overcomes some\nfundamental difficulties in realizing exact supersymmetry on the lattice. The\nLeibniz rule for the difference operator can be recovered by defining a new\nproduct on the lattice, the star product, and the chiral fermion species\ndoublers degrees of freedom can be avoided consistently. This framework is\ngeneral enough to formulate non-supersymmetric lattice field theory without\nchiral fermion problem. This lattice formulation has a nonlocal nature and is\nessentially equivalent to the corresponding continuum theory. We can show that\nthe locality of the star product is recovered exponentially in the continuum\nlimit. Possible regularization procedures are proposed.The associativity of the\nproduct and the lattice translational invariance of the formulation will be\ndiscussed."
    },
    {
        "anchor": "Ab-initio calculation of the proton and the neutron's scalar couplings\n  for new physics searches: Many low-energy, particle-physics experiments seek to reveal new fundamental\nphysics by searching for very rare scattering events on atomic nuclei. The\ninterpretation of their results requires quantifying the non-linear effects of\nthe strong interaction on the spin-independent couplings of this new physics to\nprotons and neutrons. Here we present a fully-controlled, ab-initio calculation\nof these couplings to the quarks within those constituents of nuclei. We use\nlattice quantum chromodynamics computations for the four lightest species of\nquarks and heavy-quark expansions for the remaining two. We determine each of\nthe six quark contributions with an accuracy better than 15%. Our results are\nespecially important for guiding and interpreting experimental searches for our\nuniverse's dark matter.",
        "positive": "D and D_s meson spectroscopy from lattice QCD: We present results for the low-lying spectrum of D and D_s mesons from a\nlattice QCD calculation on 2+1 flavor Clover-Wilson configurations generated by\nthe PACS-CS collaboration. In particular S- and P-wave states of charmed and\ncharmed-strange mesons are explored for pion masses down to 156MeV. For the\nheavy quark, the Fermilab method is employed. In addition to ground states,\nsome excited states are extracted using the variational method. To check our\nsetup, calculations of the charmonium spectrum are also carried out. For\ncharmonium, the low-lying spectrum agrees favorably with experiment. For\nheavy-strange and heavy-light systems substantial differences in comparison to\nexperiment values remain in channels with nearby scattering states."
    },
    {
        "anchor": "Three Phases in the 3D Abelian Higgs Model with Nonlocal Gauge\n  Interactions: We study the phase structure of the 3D nonlocal compact U(1) lattice gauge\ntheory coupled with a Higgs field by means of Monte-Carlo simulations. The\nnonlocal interactions among gauge variables are along the temporal direction\nand mimic the effect of local coupling to massless particles. We found that in\ncontrast to the 3D local abelian Higgs model which has only one phase, the\npresent model exhibits the confinement, Higgs, and Coulomb phases separated by\nthree second-order transition lines emanating from a triple point. This result\nis quite important for studies on electron fractionalization phenomena in\nstrongly-correlated electron systems. Implications to them are discussed.",
        "positive": "Numerical Simulations of d=3 SU(2) LGT in the Dual Formulation: We have developed the techniques necessary for a numerical simulation of d=3\nSU(2) Lattice Gauge theories in the dual formulation as originally developed by\nAnishetty et al . These include updating techniques that preserve the\nconstrained configuration space, efficient evaluation of 6-j symbols and a\ncertain problem associated with the positive indefiniteness of the weight\nfactors."
    },
    {
        "anchor": "Ginsparg-Wilson Games: I implement a set of tricks for constructing lattice fermion actions which\napproximately realize the Ginsparg-Wilson relation, with very promising results\nfrom simulations.",
        "positive": "Spectrum of the SU(3) Dirac operator on the lattice: Transition from\n  random matrix theory to chiral perturbation theory: We calculate complete spectra of the Kogut-Susskind Dirac operator on the\nlattice in quenched SU(3) gauge theory for various values of coupling constant\nand lattice size. From these spectra we compute the connected and disconnected\nscalar susceptibilities and find agreement with chiral random matrix theory up\nto a certain energy scale, the Thouless energy. The dependence of this scale on\nthe lattice volume is analyzed. In the case of the connected susceptibility\nthis dependence is anomalous, and we explain the reason for this. We present a\nmodel of chiral perturbation theory that is capable of describing the data\nbeyond the Thouless energy and that has a common range of applicability with\nchiral random matrix theory."
    },
    {
        "anchor": "Details of a staggered fermion data analysis: We present technical details of an analysis of pseudo-scalar data from a QCD\nsimulation with staggered fermions. The data were obtained close to the\nphysical point with an inverse lattice spacing of about 3 GeV, and $N_f=2+1+1$.\nWe compare different methods of extracting effective masses and decay constants\nin lattice units. The results of several correlated and uncorrelated fitting\nmethods are compared, both on the simulated data set, and on a synthetically\ngenerated data set.",
        "positive": "Analytical Results for Abelian Projection: Analytic methods for Abelian projection are developed, and a number of\nresults related to string tension measurements are obtained. It is proven that\neven without gauge fixing, Abelian projection yields string tensions of the\nunderlying non-Abelian theory. Strong arguments are given for similar results\nin the case where gauge fixing is employed. The subgroup used for projection\nneed only contain the center of the gauge group, and need not be Abelian. While\ngauge fixing is shown to be in principle unnecessary for the success of Abelian\nprojection, it is computationally advantageous for the same reasons that\nimproved operators, e.g., the use of fat links, are advantageous in Wilson loop\nmeasurements."
    },
    {
        "anchor": "Hopping parameter expansion to all orders using the complex Langevin\n  equation: We propose two novel formulations of the hopping parameter expansion for\nfinite density QCD using Wilson fermions, while keeping the gauge action\nintact. We use the complex Langevin equation to circumvent the sign problem in\nthe theory. We perform simulations at very high order of the expansion, such\nthat convergence is directly observable. We compare results to the full QCD\nresults, and see agreement at sufficiently high orders. These results provide\nsupport for the use of complex Langevin dynamics to study QCD at nonzero\ndensity, both in the full and the expanded theory, and for the convergence of\nthe latter.",
        "positive": "Dual simulation of the massless lattice Schwinger model with topological\n  term and non-zero chemical potential: We discuss simulation strategies for the massless lattice Schwinger model\nwith a topological term and finite chemical potential. The simulation is done\nin a dual representation where the complex action problem is solved and the\npartition function is a sum over fermion loops, fermion dimers and\nplaquette-occupation numbers. We explore strategies to update the fermion loops\ncoupled to the gauge degrees of freedom and check our results with conventional\nsimulations (without topological term and at zero chemical potential), as well\nas with exact summation on small volumes. Some physical implications of the\nresults are discussed."
    },
    {
        "anchor": "Numerical tests of the large charge expansion: We perform Monte-Carlo measurements of two and three point functions of\ncharged operators in the critical O(2) model in 3 dimensions. Our results are\ncompatible with the predictions of the large charge superfluid effective field\ntheory. To obtain reliable measurements for large values of the charge, we\nimproved the Worm algorithm and devised a measurement scheme which mitigates\nthe uncertainties due to lattice and finite size effects.",
        "positive": "Fermion bag approach to the sign problem in strongly coupled lattice QED\n  with Wilson fermions: We explore the sign problem in strongly coupled lattice QED with one flavor\nof Wilson fermions in four dimensions using the fermion bag formulation. We\nconstruct rules to compute the weight of a fermion bag and show that even\nthough the fermions are confined into bosons, fermion bags with negative\nweights do exist. By classifying fermion bags as either simple or complex, we\nfind numerical evidence that complex bags with positive and negative weights\ncome with almost equal probabilities and this leads to a severe sign problem.\nOn the other hand simple bags mostly have a positive weight. Since the complex\nbags almost cancel each other, we suggest that eliminating them from the\npartition function may be a good approximation. This modified partition\nfunction suffers only from a mild sign problem. We also find a simpler model\nwhich does not suffer from any sign problem and may still be a good\napproximation at small and intermediate values of the hopping parameter. We\nalso prove that when the hopping parameter is strictly infinite all fermion\nbags are non-negative."
    },
    {
        "anchor": "Grassmann Tensor Renormalization Group Approach to One-Flavor Lattice\n  Schwinger Model: We apply the Grassmann tensor renormalization group to the lattice\nregularized Schwinger model with one-flavor of the Wilson fermion. We study the\nphase diagram in the $(\\beta,\\kappa)$ plane performing a detailed analysis of\nthe scaling behavior of the Lee-Yang zeros and the peak height of the chiral\nsusceptibility. Our results strongly indicate that the whole range of the phase\ntransition line starting from $(\\beta,\\kappa)=(0.0,0.380665(59))$ and ending at\n$(\\infty,0.25)$ belongs to the two-dimensional Ising universality class\nsimilarly to the free fermion case.",
        "positive": "Symmetries of meson correlators in high temperature QCD with physical\n  $(u/d, s, c)$ domain-wall quarks: The correlation function of meson interpolators in $N_f=2+1+1$ lattice QCD\nwith optimal domain-wall quarks at the physical point are studied for six\ntemperatures in the range $ T \\sim$ 190-770 MeV. The meson interpolators\ninclude a complete set of Dirac bilinears, and each for six combinations of\nquark flavors. In this paper, we focus on the meson correlators of $u$ and $d$\nquarks, and discuss their implications for the effective restoration of\n$U(1)_A$ and $SU(2)_L \\times SU(2)_R$ chiral symmetries, as well as the\nemergence of the approximate $SU(2)_{CS}$ chiral spin symmetry."
    },
    {
        "anchor": "The QCD transition temperature: results with physical masses in the\n  continuum limit: The transition temperature ($T_c$) of QCD is determined by Symanzik improved\ngauge and stout-link improved staggered fermionic lattice simulations. We use\nphysical masses both for the light quarks ($m_{ud}$) and for the strange quark\n($m_s$). Four sets of lattice spacings ($N_t$=4,6,8 and 10) were used to carry\nout a continuum extrapolation. It turned out that only $N_t$=6,8 and 10 can be\nused for a controlled extrapolation, $N_t$=4 is out of the scaling region.\nSince the QCD transition is a non-singular cross-over there is no unique $T_c$.\nThus, different observables lead to different numerical $T_c$ values even in\nthe continuum and thermodynamic limit. The peak of the renormalized chiral\nsusceptibility predicts $T_c$=151(3)(3) MeV, wheres $T_c$-s based on the\nstrange quark number susceptibility and Polyakov loops result in 24(4) MeV and\n25(4) MeV larger values, respectively. Another consequence of the cross-over is\nthe non-vanishing width of the peaks even in the thermodynamic limit, which we\nalso determine. These numbers are attempted to be the full result for the\n$T$$\\neq$0 transition, though other lattice fermion formulations (e.g. Wilson)\nare needed to cross-check them.",
        "positive": "Charmed Baryon Spectroscopy from lattice QCD for $N_f = 2 + 1$ flavours: In recent years, several charmed baryons have been discovered, with more\nstates likely to be found in the future. We investigate the spectra of singly\nand doubly charmed baryons on the lattice. The spin J=1/2 and J=3/2 states are\ncalculated for both positive and negative parity."
    },
    {
        "anchor": "Bottomonium precision tests from full lattice QCD: hyperfine splitting,\n  $\u03a5$ leptonic width and $b$ quark contribution to $e^+e^- \\rightarrow$\n  hadrons: We calculate the mass difference between the $\\Upsilon$ and $\\eta_b$ and the\n$\\Upsilon$ leptonic width from lattice QCD using the Highly Improved Staggered\nQuark formalism for the $b$ quark and including $u$, $d$, $s$ and $c$ quarks in\nthe sea. We have results for lattices with lattice spacing as low as 0.03 fm\nand multiple heavy quark masses, enabling us to map out the heavy quark mass\ndependence and determine values at the $b$ quark mass. Our results are:\n$M_{\\Upsilon} -M_{\\eta_b} = 57.5(2.3)(1.0) \\,\\mathrm{MeV}$ (where the second\nuncertainty comes from neglect of quark-line disconnected correlation\nfunctions) and decay constants, $f_{\\eta_b}=724(12)$ MeV and $f_{\\Upsilon}\n=677.2(9.7)$ MeV, giving $\\Gamma(\\Upsilon \\rightarrow e^+e^-) = 1.292(37)(3)\n\\,\\mathrm{keV}$. The hyperfine splitting and leptonic width are both in good\nagreement with experiment, and provide the most accurate lattice QCD results to\ndate for these quantities by some margin. At the same time results for the time\nmoments of the vector-vector correlation function can be compared to values for\nthe $b$ quark contribution to $\\sigma(e^+e^- \\rightarrow \\mathrm{hadrons})$\ndetermined from experiment. Moments 4--10 provide a 2\\% test of QCD and yield a\n$b$ quark contribution to the anomalous magnetic moment of the muon of\n0.300(15)$\\times 10^{-10}$. Our results, covering a range of heavy quark\nmasses, may also be useful to constrain QCD-like composite theories for beyond\nthe Standard Model physics.",
        "positive": "Mollified Monte Carlo: Using a common technique for approximating distributions [generalized\nfunctions], we are able to use standard Monte Carlo methods to compute QFT\nquantities in Minkowski spacetime, under phase transitions, or when dealing\nwith coalescing stationary points."
    },
    {
        "anchor": "Photonic realization of the kappa-deformed Dirac equation: We show an implementation of a kappa-deformed Dirac equation in tight-binding\narrays of photonic waveguides. This is done with a special configuration of\ncouplings extending to second nearest neighbors. Geometric manipulations can\ncontrol these evanescent couplings. A careful study of wave packet propagation\nis presented, including the effects of deformation parameters on Zitterbewegung\nor trembling motion. In this way, we demonstrate how to recreate the effects of\na flat noncommutative spacetime -i.e., kappa-Minkowski spacetime -in simple\nexperimental setups. We touch upon elastic realizations in the section of\nConclusions.",
        "positive": "$N\u03c0$-state contamination in lattice calculations of the nucleon axial\n  form factors: The nucleon-pion-state contribution to QCD two-point and three-point\nfunctions used in lattice calculations of the nucleon axial form factors are\nstudied in chiral perturbation theory. For small quark masses this contribution\nis expected to be the dominant excited-state contamination at large time\nseparations. To leading order in chiral perturbation theory the results depend\non only two experimentally known low-energy constants and the\nnucleon-pion-state contribution to the form factors can be estimated. The\nnucleon-pion-state contribution to the axial form factor $G_{\\rm A}(Q^2)$ is at\nthe 5 percent level for a source-sink separation of 2 fm and shows almost no\ndependence on the momentum transfer $Q^2$. In contrast, for the induced\npseudoscalar form factor $\\tilde{G}_{\\rm P}(Q^2)$ the nucleon-pion-state\ncontribution shows a rather strong dependence on $Q^2$ and leads to a 10 to 40\npercent underestimation of $\\tilde{G}_{\\rm P}(Q^2)$ at small momentum\ntransfers. The ChPT results can be used to analytically remove the\nnucleon-pion-state contribution from lattice data. Performing this removal for\nlattice data generated by the PACS collaboration we find agreement with\nexperimental data and the predictions of the pion-pole dominance model. The\nremoval works surprisingly well even for source-sink separations as small as\n1.3 fm."
    },
    {
        "anchor": "Non-perturbative investigation of the fermion-Higgs sector of the\n  standard model: We present results for the renormalized quartic self-coupling $\\lm_R$ and the\nrenormalized Yukawa coupling $y_R$ in a fermion-Higgs model with two SU(2)\ndoublets, indicating that with the standard lattice regulator these couplings\ncannot become very strong.",
        "positive": "Report on the 2019 Lattice Diversity and Inclusivity Survey: We report on the results of a survey to assess diversity and inclusivity in\nthe Lattice community as one of the duties of a newly formed Committee on\nDiversity and Inclusivity in the Lattice community."
    },
    {
        "anchor": "Statistical analysis and the equivalent of a Thouless energy in lattice\n  QCD Dirac spectra: Random Matrix Theory (RMT) is a powerful statistical tool to model spectral\nfluctuations. This approach has also found fruitful application in Quantum\nChromodynamics (QCD). Importantly, RMT provides very efficient means to\nseparate different scales in the spectral fluctuations. We try to identify the\nequivalent of a Thouless energy in complete spectra of the QCD Dirac operator\nfor staggered fermions from SU(2) lattice gauge theory for different lattice\nsize and gauge couplings. In disordered systems, the Thouless energy sets the\nuniversal scale for which RMT applies. This relates to recent theoretical\nstudies which suggest a strong analogy between QCD and disordered systems. The\nwealth of data allows us to analyze several statistical measures in the bulk of\nthe spectrum with high quality. We find deviations which allows us to give an\nestimate for this universal scale. Other deviations than these are seen whose\npossible origin is discussed. Moreover, we work out higher order correlators as\nwell, in particular three--point correlation functions.",
        "positive": "Nuclear Physics from Lattice QCD: We review recent progress toward establishing lattice Quantum Chromodynamics\nas a predictive calculational framework for nuclear physics. A survey of the\ncurrent techniques that are used to extract low-energy hadronic scattering\namplitudes and interactions is followed by a review of recent two-body and\nfew-body calculations by the NPLQCD collaboration and others. An outline of the\nnuclear physics that is expected to be accomplished with Lattice QCD in the\nnext decade, along with estimates of the required computational resources, is\npresented."
    },
    {
        "anchor": "Light scalar mesons in 2+1 flavor full QCD: We study the a_0 and K_0^* light scalar mesons in 2+1 flavor full QCD.\nParticular attention is paid to fitting excited states, with an eye toward\ndetermining whether scattering states are revealed. An ultimate goal will be to\nsee how dynamical quarks affect the picture outlined with an earlier quenched\nstudy using overlap fermions, namely, that it is the a_0(1450), not the\na_0(980), which is the lowest $\\bar{q}q$ isovector scalar state.",
        "positive": "Gluon gravitational structure of hadrons of different spin: The gravitational form factors (GFFs) of hadrons encode the matrix elements\nof the energy momentum tensor of QCD. These quantities describe how energy,\nspin, and various mechanical properties of hadrons are carried by their quark\nand gluon constituents. We present the gluon GFFs of the pion, nucleon, $\\rho$\nmeson, and $\\Delta$ baryon as functions of the squared momentum transfer $t$ in\nthe region $0 \\leq -t < 2 \\; \\text{GeV}^2$, as determined in a lattice QCD\nstudy with pion mass $m_{\\pi} = 450(5) \\; \\text{MeV}$. By fitting the extracted\nGFFs using multipole and z-parameter expansion functional forms, we extract\nvarious gluon contributions to the energy, pressure, and shear force\ndistributions of the hadrons in the 3D and 2D Breit frames as well as in the\ninfinite momentum frame. We also obtain estimates for the corresponding gluon\nmechanical and mass radii, as well as the forward-limit gluon contributions to\nthe momentum fraction and angular momentum of the hadrons."
    },
    {
        "anchor": "Lyncs-API: a Python API for Lattice QCD applications: We present Lyncs-API, a Python API for Lattice QCD applications currently\nunder development. Lyncs aims to bring several widely used libraries for\nLattice QCD under a common framework. Lyncs flexibly links to libraries for\nCPUs and GPUs in a way that can accommodate additional computing architectures\nas these arise, achieving performance-portability for the calculations while\nmaintaining the same high-level workflow. Lyncs distributes calculations using\nDask and mpi4py, with bindings to the libraries automatically generated by\ncppyy. While Lyncs is designed to allow linking to multiple libraries, we focus\non a set of targeted packages that include DDalphaAMG, tmLQCD, QUDA and c-lime.\nMore libraries will be added in the future. We also develop generic-purpose\ntools for facilitating the usage of Python in Lattice QCD and HPC in general.\nThe project is open-source, community-oriented and available on Github.",
        "positive": "Topological configurations of Yang-Mills field responsible for\n  magnetic-monopole loops as quark confiner: We have given a new description of the lattice Yang-Mills theory a la\nCho-Faddeev-Niemi-Shabanov, which has enabled us to confirm in a\ngauge-independent manner \"Abelian\"-dominance and magnetic-monopole dominance in\nthe Wilson loop average, yielding a gauge-independent dual superconductor\npicture for quark confinement. In particular, we have given a new procedure\n(called reduction) for obtaining a gauge-independent magnetic monopole from a\ngiven Yang-Mills field. In this talk, we demonstrate how some of known\ntopological configurations in the SU(2) Yang-Mills theory such as merons and\ninstantons generate closed loops of magnetic-monopole current as the quark\nconfiner, both of which are characterized by the gauge-invariant topological\nindex, topological charge (density) and magnetic charge (density),\nrespectively. We also try to detect which type of topological configurations\nexist in the lattice data involving magnetic-monopole loops generated by Monte\nCarlo simulation. Here we apply a new geometrical algorithm based on\n\"computational homology\" to discriminating each closed loop from clusters of\nmagnetic-monopole current, since the magnetic-monopole current on a lattice is\ninteger valued."
    },
    {
        "anchor": "Perfect Gauge Actions on Anisotropic Lattices: We present a method for constructing classically perfect anisotropic actions\nfor SU(3) gauge theory based on a present isotropic Fixed Point Action. The\naction is parametrised using smeared (``fat'') links. The construction is done\nexplicitly for anisotropy $\\xi=a_s/a_t=2,4$ and the renormalised anisotropies\nare determined using the torelon dispersion relation. Quantities such as the\nstatic quark-antiquark potential, the critical temperature of the deconfining\nphase transition and the low-lying glueball spectrum are measured as well. It\nturns out that the procedure presented works, the renormalised anisotropy is\nsmall and the parametrisation describes the full action well. Issues such as\nthe application of the method for scalar fields as well as for the quadratic\napproximation to gauge theory, measurements of autocorrelation times of simple\noperators and of the computational overhead are also covered. A (more compact)\npaper about this classically perfect anisotropic gauge action is in\npreparation.",
        "positive": "Topological susceptibility at zero and finite $T$ in SU(3) Yang-Mills\n  theory: We determine the topological susceptibility $\\chi$ at T=0 in pure SU(3) gauge\ntheory and its behaviour at finite $T$ across the deconfining transition. We\nuse an improved topological charge density operator. $\\chi$ drops sharply by\none order of magnitude at the deconfining temperature $T_c$."
    },
    {
        "anchor": "Tensor renormalization group approach to (1+1)-dimensional SU(2)\n  principal chiral model at finite density: We apply the tensor renormalization group method to the (1+1)-dimensional\nSU(2) principal chiral model at finite chemical potential with the use of the\nGauss-Legendre quadrature to discretize the SU(2) Lie group. The internal\nenergy at vanishing chemical potential $\\mu=0$ shows good consistency with the\nprediction of the strong and weak coupling expansions. This indicates an\neffectiveness of the Gauss-Legendre quadrature for the partitioning of the\nSU(2) Lie group. In the finite density region with $\\mu\\ne 0$ at the strong\ncoupling we observe the Silver-Blaze phenomenon for the number density.",
        "positive": "$P$-wave $\u03c0\u03c0$ scattering and the $\u03c1$ resonance from lattice QCD: We calculate the parameters describing elastic $I=1$, $P$-wave $\\pi\\pi$\nscattering using lattice QCD with $2+1$ flavors of clover fermions. Our\ncalculation is performed with a pion mass of $m_\\pi \\approx 320\\:\\:{\\rm MeV}$\nand a lattice size of $L\\approx 3.6$ fm. We construct the two-point correlation\nmatrices with both quark-antiquark and two-hadron interpolating fields using a\ncombination of smeared forward, sequential and stochastic propagators. The\nspectra in all relevant irreducible representations for total momenta\n$|\\vec{P}| \\leq \\sqrt{3} \\frac{2\\pi}{L}$ are extracted with two alternative\nmethods: a variational analysis as well as multi-exponential matrix fits. We\nperform an analysis using L\\\"uscher's formalism for the energies below the\ninelastic thresholds, and investigate several phase shift models, including\npossible nonresonant contributions. We find that our data are well described by\nthe minimal Breit-Wigner form, with no statistically significant nonresonant\ncomponent. In determining the $\\rho$ resonance mass and coupling we compare two\ndifferent approaches: fitting the individually extracted phase shifts versus\nfitting the $t$-matrix model directly to the energy spectrum. We find that both\nmethods give consistent results, and at a pion mass of\n$am_{\\pi}=0.18295(36)_{stat}$ obtain $g_{\\rho\\pi\\pi} =\n5.69(13)_{stat}(16)_{sys}$, $am_\\rho = 0.4609(16)_{stat}(14)_{sys}$, and\n$am_{\\rho}/am_{N} = 0.7476(38)_{stat}(23)_{sys} $, where the first uncertainty\nis statistical and the second is the systematic uncertainty due to the choice\nof fit ranges."
    },
    {
        "anchor": "Quarkonium in-medium properties from realistic lattice NRQCD: We present the final results of our high statistics study on the properties\nof bottomonium and charmonium at finite temperature. We focus on the\ntemperature range around the crossover transition $150\\leq T\\leq 410$MeV,\nrelevant for current heavy ion collision experiments. The QCD medium degrees of\nfreedom which consist of dynamical u,d, and s quarks and gluons are captured by\nrealistic state-of-the art ($m_\\pi\\approx 161$MeV) lattice QCD simulations of\nthe HotQCD collaboration. For the heavy quarks we deploy the non-relativistic\neffective field theory of QCD, NRQCD. The in-medium properties of quarkonium\nare deduced from their spectral functions, which are reconstructed using\nimproved and novel Bayesian approaches. Through a systematic analysis we shed\nlight on the origin of the discrepancies in melting temperatures previously\nreported in the literature, showing that they are owed to underestimated\nmethods uncertainties of the deployed spectral reconstructions. Our simulations\ncorroborate a picture of sequential in-medium modification, ordered according\nto the vacuum binding energy of the states. As a central quantitative result,\nour study reveals how the mass of the heavy quarkonium ground state reduces as\ntemperature increases. The observed spectral modifications are interpreted in\nthe light of, and compared to previous studies based on the complex lattice\npotential for heavy quarkonium. Thus for the first time we provide a robust\npicture of in-medium heavy quarkonium modification in the quark-gluon plasma\nconsistent among different non-relativistic methods. We also critically discuss\nthe perspectives for improving on these results.",
        "positive": "Spectral reconstruction in NRQCD via the Backus-Gilbert method: We present progress results from the FASTSUM collaboration's programme to\ndetermine the spectrum of the bottomonium system as a function of temperature\nusing a variety of approaches. In this contribution, the Backus Gilbert method\nis used to reconstruct spectral functions from NRQCD meson correlator data from\nFASTSUM's anisotropic ensembles at nonzero temperature. We focus in particular\non the resolving power of the method, providing a demonstration of how the\nunderlying resolution functions can be probed by exploiting the Laplacian\nnature of the NRQCD kernel. We conclude with estimates of the bottomonium\nground state mass and widths at nonzero temperature."
    },
    {
        "anchor": "On the gauge invariant path-integral measure for the overlap Weyl\n  fermions in $\\underline{16}$ of SO(10): We consider the lattice formulation of SO(10) chiral gauge theory with\nleft-handed Weyl fermions in the sixteen dimensional spinor representation\n($\\underline{16}$) within the framework of the Overlap fermion/the\nGinsparg-Wilson relation. We define a manifestly gauge-invariant path-integral\nmeasure for the left-handed Weyl field using all the components of the Dirac\nfield, but the right-handed part of which is just saturated completely by\ninserting a suitable product of the SO(10)-invariant 't Hooft vertices in terms\nof the right-handed field. The definition of the measure applies to all\npossible topological sectors. The measure possesses all required transformation\nproperties under lattice symmetries and the induced effective action is CP\ninvariant. The global U(1) symmetry of the left-handed field is anomalous due\nto the non-trivial transformation of the measure, while that of the\nright-handed field is explicitly broken by the 't Hooft vertices. There remains\nthe issue of locality in the gauge-field dependence of the Weyl fermion\nmeasure, but the question can be addressed in the weak gauge-coupling expansion\nat least using Monte Carlo methods without encountering the sign problem. We\nalso discuss the relations of our formulation to other approaches/proposals to\ndecouple the species-doubling/mirror degrees of freedom. Those include\nEichten-Preskill model, Ginsparg-Wilson Mirror-fermion model, Domain wall\nfermion model with the boundary Eichten-Preskill term, 4D Topological\nInsulator/Superconductor with gapped boundary phase, and the recent studies on\nthe PMS phase/\"Mass without symmetry breaking\". We clarify the similarity and\nthe difference in technical detail and show that our proposal is a well-defined\ntesting ground for that basic question.",
        "positive": "Various Representations of Infrared Effective Lattice SU(2) Gluodynamics: We study various representations of infrared effective theory of SU(2)\ngluodynamics starting from the Abelian monopole action derived recently by\nnumerical calculations in the Maximal Abelian projection. In particular we\nderive the string model and the dual Abelian-Higgs (dual Ginzburg-Landau) model\nwhich corresponds to infrared SU(2) gluodynamics. It occurs that the classical\nstring tension in the string model is of the same order as the string tension\nin quantum SU(2) gluodynamics."
    },
    {
        "anchor": "Worm Algorithm for Abelian Gauge-Higgs Models: We present the surface worm algorithm (SWA) which is a generalization of the\nProkof'ev Svistunov worm algorithm to perform the simulation of the dual\nrepresentation (surfaces and loops) of Abelian gauge-Higgs models on a lattice.\nWe compare the SWA to a local Metropolis update in the dual representation and\nshow that the SWA outperforms the local update for a wide range of parameters.",
        "positive": "Oscillatory terms in the domain wall transfer matrix: We study the transfer matrix for domain wall fermions to understand the\norigin and significance of oscillatory contributions to hadron correlation\nfunctions that arise for M >1. For a free particle in one space, one time, and\none flavor dimension, the eigenmodes of the one-body operator appearing in the\ntransfer matrix are calculated, and the role of the negative eigenmodes arising\nwhen M > 1 is studied. In the case of three space dimensions, oscillatory\nbehavior for hadron correlation functions in QCD is shown to emerge for free\nfermions when M exceeds 1, and to increase with increasing M. Analogous\nbehavior is observed for domain wall fermions on HYP smeared MILC lattices, and\na procedure is demonstrated for subtracting oscillating terms from physical\nobservables."
    },
    {
        "anchor": "Minimally doubled fermions at one-loop level: Single fermionic degrees of freedom together with standard chiral symmetry at\nfinite lattice spacing, correct continuum limit and local interactions only are\nprecluded by the Nielsen-Ninomiya no-go theorem. The class of minimally doubled\nfermion actions exhibits exactly two chiral modes. Recent interest in these\nactions has been sparked by the investigation of fermionic actions defined on\n\"hyperdiamond\" lattices. Due to the necessity of breaking hypercubic symmetry\nexplicitly, radiative corrections generate operator mixings with relevant and\nmarginal operators that should vanish in continuum QCD. These cannot be avoided\nand must be taken into account in particular by a peculiar wave-function\nrenormalisation and additive momentum renormalisation. Renormalisation\nproperties at one-loop level of the self-energy, local bilinears and conserved\nvector and axial-vector currents are presented for Borici-Creutz and\nKarsten-Wilczek actions. Distinct differences and similarities between both\nactions are elucidated.",
        "positive": "$B \\to K^* + \u03b3$ and $B_s \\to \u03c6+ \u03b3$ on the Lattice: A lattice calculation of the form factors that determine the ``hadronization\nratios'', such as $R_{K^*}$ and $R_{\\phi}$, where $R_{K^*} \\equiv [\\Gamma ($B\n\\to K^* \\gamma$)/\\Gamma(b \\to s \\gamma)]$, is presented in the quenched\napproximation. Lattice data shows strong evidence for the scaling law suggested\nby heavy quark symmetry for one of the form factors ({\\it i.e.}\\ $T_2$). The\ndata also gives strong support for the simple pole ansatz for the $q^2$\ndependence of $T_2$ in the range of available $q^2$. We thus find $T_2(0) = .10\n\\pm.01\\pm.03$ yielding $R_{K^*} =(6.0\\pm1.2\\pm3.4)\\%$; we also find\n$R_{\\phi}=(6.6\\pm1.3\\pm3.7)\\%$."
    },
    {
        "anchor": "Quark disconnected diagrams in chiral perturbation theory: We show how quark-disconnected and quark-connected contributions to hadronic\nn-point functions can be written as independent correlators for which one can\nderive expressions in partially quenched chiral effective theory. As an example\nwe apply the idea to the case of the hadronic vacuum polarisation. In\nparticular, we consider the cases of the Nf = 2 theory without and with a\npartially quenched strange quark and also the Nf = 2 + 1 theory. In the latter\ntwo cases a parameter-free prediction for the disconnected contribution at NLO\nin the effective theory is given. Finally we show how twisted boundary\nconditions can then be used in lattice QCD to improve the q^2 resolution in the\nconnected contributions even when flavour singlet operators are considered.",
        "positive": "Long-range electroweak amplitudes of single hadrons from Euclidean\n  finite-volume correlation functions: A relation is presented between single-hadron long-range matrix elements\ndefined in a finite Euclidean spacetime, and the corresponding infinite-volume\nMinkowski amplitudes. This relation is valid in the kinematic region where any\nnumber of two-hadron states can simultaneously go on shell, so that the effects\nof strongly-coupled intermediate channels are included. These channels can\nconsist of non-identical particles with arbitrary intrinsic spins. The result\naccommodates general Lorentz structures as well as non-zero momentum transfer\nfor the two external currents inserted between the single-hadron states. The\nformalism, therefore, generalizes the work by Christ et al.~[Phys.Rev. D91\n114510 (2015)], and extends the reach of lattice quantum chromodynamics (QCD)\nto a wide class of new observables beyond meson mixing and rare decays.\nApplications include Compton scattering of the pion ($\\pi \\gamma^\\star \\to [\\pi\n\\pi, K \\overline K] \\to \\pi \\gamma^\\star$), kaon ($K \\gamma^\\star \\to [\\pi K,\n\\eta K] \\to K \\gamma^\\star$) and nucleon ($N \\gamma^\\star \\to N \\pi \\to N\n\\gamma^\\star$), as well as double-$\\beta$ decays, and radiative corrections to\nthe single-$\\beta$ decay, of QCD-stable hadrons. The framework presented will\nfurther facilitate generalization of the result to studies of nuclear\namplitudes involving two currents from lattice QCD."
    },
    {
        "anchor": "Lattice Gauge Theory of Three Dimensional Thirring Model: Three dimensional Thirring model with $N$ four-component Dirac fermions,\nreformulated as a lattice gauge theory, is studied by computer simulation.\nAccording to an $8^{3}$ data and preliminary $16^3$ data, chiral symmetry is\nfound to be spontaneously broken for $N=2,\\;4$ and 6. $N=2$ data exhibits long\ntail of the non-vanishing chiral condensate into weak coupling region, and\n$N=6$ case shows phase separation between the strong coupling region and the\nweak coupling region. Although the comparison between $8^3$ data and $16^3$\ndata shows large finite volume effects, an existence of the critical fermion\nflavor number $N_{{\\rm cr}}$ $(2<N_{{\\rm cr}}<6)$ for which the chiral behavior\nchanges its character, is suggested by the current numerical data.",
        "positive": "Perturbative renormalization factors of $\u0394S = 1$ four-quark\n  operators for domain-wall QCD: Renormalization factors for $\\Delta S =1$ four-quark operators in the\neffective weak Hamiltonian are perturbatively evaluated in domain-wall QCD. The\none-loop corrections of $\\Delta S=1$ four-quark operators consist of two types\nof diagrams: one is gluon exchange between quark lines and the other is penguin\ndiagrams containing quark loops. Combining both contributions, our results\nallow a lattice calculation of the amplitude for $K\\to \\pi\\pi$ decays with\n$O(g^2)$ corrections included."
    },
    {
        "anchor": "Simulations of Dynamically Triangulated Gravity -- an Algorithm for\n  Arbitrary Dimension: Recent models for discrete euclidean quantum gravity incorporate a sum over\nsimplicial triangulations. We describe an algorithm for simulating such models\nin general dimensions. As illustration we show results from simulations in four\ndimensions",
        "positive": "Exponential corrections to low-temperature expansion of 2D non-abelian\n  models: The thermodynamic limit of certain exponential corrections to the weak\ncoupling expansion of two-dimensional models is investigated. The expectation\nvalues of operators contributing to the first order coefficient of the\nlow-temperature expansion of the free energy are calculated for the order\nO(e^{-\\beta}). They are proven to diverge logarithmically with the volume for\nnon-abelian models."
    },
    {
        "anchor": "The heavy quarkonium spectrum from quenched lattice QCD: We present results of simulations of the quenched quarkonium spectrum at two\nvalues of the lattice spacing and for quark masses around $m_c$ using the\ntadpole improved clover action. Attention is focussed on the lowest lying S and\nP states, and the triplet fine structure is obtained for the first time using a\nrelativistic action.",
        "positive": "Strange nucleon form factors with $N_f = 2 + 1$ O($a$)-improved Wilson\n  fermions: We present preliminary results for strangeness form factors of the nucleon\ncomputed on the CLS ensembles with $N_f=2+1$ flavors of O($a$)-improved Wilson\nfermions. Our calculations are performed at two values of the lattice spacing\n($a \\in \\{0.064, 0.086\\} \\,\\mathrm{fm}$) and three values of the pion mass\n($m_\\pi \\in \\{ 200, 280, 340\\} \\,\\mathrm{MeV}$). The determination of\nstrangeness form factors proceeds by computing quark-disconnected diagrams, for\nwhich we employ hierarchical probing in four dimensions in order to deal with\nthis most challenging part of the calculation. Furthermore, we investigate\nseveral source-sink separations to check for excited-state contamination."
    },
    {
        "anchor": "Non-perturbative Heavy Quark Effective Theory: Introduction and Status: We give an introduction to Heavy Quark Effective Theory (HQET). Our emphasis\nis on its formulation non-perturbative in the strong coupling, including the\nnon-perturbative determination of the parameters in the HQET Lagrangian. In a\nsecond part we review the present status of HQET on the lattice, largely based\non work of the ALPHA collaboration in the last few years. We finally discuss\nopportunities and challenges.",
        "positive": "The Relationship of the Laplacian Gauge to the Landau Gauge: The Laplacian gauge for gauge group SU(N) is discussed in perturbation\ntheory. It is shown that to the lowest non-trivial order, O(g^1),\nconfigurations in the Laplacian gauge automatically satisfy the (finite\ndifference) Landau gauge condition. Laplacian gauge fixed configurations are\nexamined numerically and it is seen that to O(g^2) they do not remain in the\nLandau gauge."
    },
    {
        "anchor": "Properties of the non-Gaussian fixed point in 4D compact U(1) lattice\n  gauge theory: We examine selected properties of the gauge-ball spectrum and fermionic\nvariables in the vicinity of the recently discussed non-Gaussian fixed point of\n4D compact U(1) lattice gauge theory within the quenched approximation.\nApproaching the critical point from within the confinement phase, our data\nsupport scaling of $T1^{+-}$ gauge-ball states in units of the string tension\nsquare root. The analysis of the chiral condensate within the framework of a\nscaling form for the equation of state suggests non mean-field values for the\nmagnetic exponents $\\delta$ and $\\beta_{exp}$.",
        "positive": "Determination of $\\varepsilon_K$ using lattice QCD inputs: We present results for the indirect CP violation parameter $\\varepsilon_K$\ndetermined directly from the standard model using lattice QCD to fix the inputs\n$\\hat{B}_K$, $\\xi_0$, $|V_{us}|$, and $|V_{cb}|$. We use the FLAG and SWME\nresults for $\\hat{B}_K$. We use the RBC-UKQCD result for $\\xi_0$ determined\nusing the experimental value of $\\varepsilon'/\\varepsilon$ and the lattice\nresult of $\\mathrm{Im}\\,A_2$. To set the Wolfenstein parameter $\\lambda$, we\nuse $|V_{us}|$, which is determined from $K_{\\ell3}$ and $K_{\\mu2}$ decays\ncombined with lattice evaluations of the $K \\to \\pi \\ell \\nu$ vector form\nfactor and $f_K$. To set the Wolfenstein parameter $A$, we use the FNAL/MILC\nresults for $|V_{cb}|$, which are determined from the exclusive decay $\\bar{B}\n\\to D^* \\ell \\bar{\\nu}$ and the axial form factor at zero recoil. We also use\nthe inclusive $|V_{cb}|$ obtained using the heavy quark expansion based on QCD\nsum rules and the OPE. We compare the results with those for exclusive\n$|V_{cb}|$. We find that the standard model prediction of $\\varepsilon_K$ with\nexclusive $|V_{cb}|$ (lattice QCD results) is lower than the experimental value\nby 3.4$\\sigma$. However, we observe no tension in $\\varepsilon_K$ determined\nfrom inclusive $|V_{cb}|$."
    },
    {
        "anchor": "Systematic Improvement of $x$-dependent Unpolarized Nucleon Generalized\n  Parton Distribution in Lattice-QCD Calculation: We present a first study of the effects of renormalization-group resummation\n(RGR) and leading-renormalon resummation (LRR) on the systematic errors of the\nunpolarized isovector nucleon generalized parton distribution in the framework\nof large-momentum effective theory (LaMET). This work is done using lattice\ngauge ensembles generated by the MILC collaboration, consisting of 2+1+1\nflavors of highly improved staggered quarks with a physical pion mass at\nlattice spacing $a\\approx 0.09$~fm and a box width $L\\approx 5.76$~fm. We\npresent results for the nucleon $H$ and $E$ GPDs with average boost momentum\n$P_z\\approx 2$~GeV at momentum transfers $Q^2=[0, 0.97]$~GeV$^2$ at skewness\n$\\xi=0$ as well as $Q^2\\in 0.23$ GeV$^2$ at $\\xi=0.1$, renormalized in the\n$\\overline{\\rm MS}$ scheme at scale $\\mu=2.0$ GeV, with two- and one-loop\nmatching, respectively. We demonstrate that the simultaneous application of RGR\nand LRR significantly reduces the systematic errors in renormalized matrix\nelements and distributions for both the zero and nonzero skewness GPDs, and\nthat it is necessary to include both RGR and LRR at higher orders in the\nmatching and renormalization processes.",
        "positive": "Calculation of nucleon strange quark content with dynamical overlap\n  quarks: We calculate the nucleon strange quark content directly from disconnected\nthree-point functions. Numerical simulations are carried out in two-flavor QCD\nusing the overlap quark action with up and down quark masses down to a fifth of\nthe physical strange quark mass. To improve the statistical accuracy, we\ncalculate the nucleon two-point functions with the low-mode averaging\ntechnique, whereas the all-to-all quark propagator is used for the disconnected\nquark loop. We obtain the y parameter, which is the ratio of the strange and\nlight quark contents, y = 0.024(45) at the physical point. This is in a good\nagreement with our earlier calculation from the nucleon spectrum through the\nFeynman-Hellmann theorem."
    },
    {
        "anchor": "Full QCD in external chromomagnetic field: We investigate the deconfining phase transition in full QCD with two flavors\nof staggered fermions in presence of a constant abelian chromomagnetic field.\nWe find that the deconfinement temperature decreases and eventually goes to\nzero by increasing the strength of the chromomagnetic field. Moreover our\nresults suggest that the chiral transition coincides with the deconfinement\ntransition and therefore even the chiral critical temperature depends on the\napplied chromomagnetic field. We also find that the chiral condensate increases\nwith the strength of the chromomagnetic field.",
        "positive": "Non-Hermitian Random Matrix Theory and Lattice QCD with Chemical\n  Potential: In quantum chromodynamics (QCD) at nonzero chemical potential, the\neigenvalues of the Dirac operator are scattered in the complex plane. Can the\nfluctuation properties of the Dirac spectrum be described by universal\npredictions of non-Hermitian random matrix theory? We introduce an unfolding\nprocedure for complex eigenvalues and apply it to data from lattice QCD at\nfinite chemical potential $\\mu$ to construct the nearest-neighbor spacing\ndistribution of adjacent eigenvalues in the complex plane. For intermediate\nvalues of $\\mu$, we find agreement with predictions of the Ginibre ensemble of\nrandom matrix theory, both in the confinement and in the deconfinement phase."
    },
    {
        "anchor": "SU(2) and SU(3) chiral perturbation theory analyses on meson and baryon\n  masses in 2+1 flavor lattice QCD: We investigate the quark mass dependence of meson and baryon masses obtained\nfrom 2+1 flavor dynamical quark simulations performed by the PACS-CS\nCollaboration. With the use of SU(2) and SU(3) chiral perturbation theories up\nto NLO, we examine the chiral behavior of the pseudoscalar meson masses and the\ndecay constants in terms of the degenerate up-down quark mass ranging form 3\nMeV to 24 MeV and two choices of the strange quark mass around the physical\nvalue. We discuss the convergence of the SU(2) and SU(3) chiral expansions and\npresent the results for the low energy constants. We find that the SU(3)\nexpansion is not convergent at NLO for the physical strange quark mass. The\nchiral behavior of the nucleon mass is also discussed based on the SU(2) heavy\nbaryon chiral perturbation theory up to NNLO. Our results show that the\nexpansion is well behaved only up to m_pi^2 ~ 0.2 GeV^2.",
        "positive": "Investigation of light and heavy tetraquark candidates using lattice QCD: We review the status of an ongoing long-term lattice investigation of the\nspectrum and structure of tetraquark candidates. We focus on the light scalar\nmeson $a_0(980)$. First steps regarding the study of a possibly existing $c c\n\\bar{c} \\bar{c}$ tetraquark are also outlined."
    },
    {
        "anchor": "Finite-density gauge correlation functions in QC2D: 2-color QCD is the simplest QCD-like theory which is accessible to lattice\nsimulations at finite density. It therefore plays an important role to test\nqualitative features and to provide benchmarks to other methods and models,\nwhich do not suffer from a sign problem. To this end, we determine the\nminimal-Landau-gauge propagators and 3-point vertices in this theory over a\nwide range of densities, the vacuum, and at both finite temperature and\ndensity. The results show that there is essentially no modification of the\ngauge sector in the low-temperature, low-density phase. Even outside this phase\nonly mild modifications appear, mostly in the chromoelectric sector.",
        "positive": "The Mechanism of Complex Langevin Simulations: We discuss conditions under which expectation values computed from a complex\nLangevin process $Z$ will converge to integral averages over a given complex\nvalued weight function. The difficulties in proving a general result are\npointed out. For complex valued polynomial actions, it is shown that for a\nprocess converging to a strongly stationary process one gets the correct answer\nfor averages of polynomials if $c_{\\tau}(k) \\equiv E(e^{ikZ(\\tau)}) $ satisfies\ncertain conditions. If these conditions are not satisfied, then the stochastic\nprocess is not necessarily described by a complex Fokker Planck equation. The\nresult is illustrated with the exactly solvable complex frequency harmonic\noscillator."
    },
    {
        "anchor": "Gauge invariant Z_2 vortex vacuum textures and the SU(2) gluon\n  condensate: For SU(2) lattice gauge theory, a new SO(3) cooling procedure is proposed\nwhich removes the SU(2)/Z(2) coset fields from the lattice configurations and\nreveals a Z(2) vortex vacuum texture different from the P-vortex content\nobtained in the maximal center gauge. Cooling can be restricted in a\nrenormalization group invariant way by a parameter controlling the remaining\nSO(3) action density. A gauge invariant Z(2) vortex vacuum emerges\nasymptotically if cooling is not restricted. This ``vortex texture'' does not\nsupport the string tension or a finite part of it. The SU(2) action density\nassociated with the new Z(2) vortex texture has a smooth extrapolation to the\ncontinuum limit. We propose an interpretation as a mass dimension four\ncondensate related to the gluon condensate featuring in the operator product\nexpansion.",
        "positive": "Computation of hybrid static potentials in SU(3) lattice gauge theory: We compute hybrid static potentials in SU(3) lattice gauge theory. We present\na method to generate a large set of suitable creation operators with defined\nquantum numbers from elementary building blocks. We show preliminary results\nfor several channels and discuss, which structures of the gluonic flux tube\nseem to be realized by the ground states in these channels."
    },
    {
        "anchor": "New results on $\u03b3_{\\rm str}$ in 2D quantum gravity using Regge\n  calculus: We study 2D quantum gravity on spherical topologies using the Regge calculus\napproach. Our goal is to shed new light upon the validity of the Regge approach\nto quantum gravity, which has recently been questioned in the literature. We\nincorporate an $R^2$ interaction term and investigate its effect on the value\nof the string susceptibility exponent $\\gamma_{\\rm str}$ using two different\nfinite-size scaling Ans\\\"atze. Our results suggest severe shortcomings of the\nmethods used so far to determine $\\GS$ and show a possible cure of the\nproblems. To have better control over the influence of irregular vertices, we\nchoose besides the almost regular triangulation of the sphere as the surface of\na cube a random triangulation according to the Voronoi-Delaunay prescription.",
        "positive": "Non-perturbative Pion Matrix Element of a twist-2 operator from the\n  Lattice: We give a continuum limit value of the lowest moment of a twist-2 operator in\npion states from non-perturbative lattice calculations. We find that the\nnon-perturbatively obtained renormalization group invariant matrix element is\n<x>_{RGI} = 0.179(11), which corresponds to <x>^{MSbar}(2 GeV) = 0.246(15). In\nobtaining the renormalization group invariant matrix element, we have\ncontrolled important systematic errors that appear in typical lattice\nsimulations, such as non-perturbative renormalization, finite size effects and\neffects of a non-vanishing lattice spacing. The crucial limitation of our\ncalculation is the use of the quenched approximation. Another question that\nremains not fully clarified is the chiral extrapolation of the numerical data."
    },
    {
        "anchor": "Lattice realization of the axial $U(1)$ non-invertible symmetry: In $U(1)$ lattice gauge theory with compact $U(1)$ variables, we construct\nthe symmetry operator, i.e., the topological defect, for the axial $U(1)$\nnon-invertible symmetry. This requires a lattice formulation of chiral gauge\ntheory with an anomalous matter content and we employ the lattice formulation\non the basis of the Ginsparg--Wilson relation. The invariance of the symmetry\noperator under the gauge transformation of the gauge field on the defect is\nrealized, imitating the prescription by Karasik in continuum theory, by\nintegrating the lattice Chern--Simons term on the defect over \\emph{smooth\\/}\nlattice gauge transformations. The projection operator for allowed magnetic\nfluxes on the defect then emerges with lattice regularization. The resulting\nsymmetry operator is manifestly invariant under lattice gauge transformations.\nIn an appendix, we give another way of construction of the symmetry operator on\nthe basis of a 3D $\\mathbb{Z}_N$ TQFT, the level-$N$ BF theory on the lattice.",
        "positive": "Two dimensional CP^2 Model with \u03b8-term and Topological Charge\n  Distributions: Topological charge distributions in 2 dimensional CP^2 model with theta-term\nis calculated. In strong coupling regions, topological charge distribution is\napproximately given by Gaussian form as a function of topological charge and\nthis behavior leads to the first order phase transition at \\theta=\\pi. In weak\ncoupling regions it shows non-Gaussian distribution and the first order phase\ntransition disappears. Free energy as a function of \\theta shows \"flattening\"\nbehavior at theta=theta_f<pi, when we calculate the free energy directly from\ntopological charge distribution. Possible origin of this flattening phenomena\nis prensented."
    },
    {
        "anchor": "Inhomogeneous phases in the 1+1 dimensional Gross-Neveu model at finite\n  number of fermion flavors: We study the phase diagram of the 1+1 dimensional Gross-Neveu model at finite\nnumber of fermion flavors using lattice field theory. Numerical results are\npresented, which indicate the existence of an inhomogeneous phase, where the\nchiral condensate is a spatially oscillating function.",
        "positive": "Stealth dark matter and gravitational waves: I present first results from ongoing lattice investigations into the\nfinite-temperature dynamics of stealth dark matter, which adds to the standard\nmodel a new SU(4) gauge sector with four moderately heavy fundamental fermions.\nThis work by the Lattice Strong Dynamics Collaboration builds on past studies\nof direct detection and collider searches for stealth dark matter, by analyzing\nthe early-universe SU(4) confinement transition, which produces a stochastic\nbackground of gravitational waves if it is first order. In addition to\ndelineating the parameter space in which a first-order transition is observed,\nI discuss the quantities we are analyzing in order to predict the resulting\ngravitational-wave spectrum."
    },
    {
        "anchor": "Topological susceptibility at high temperature on the lattice: QCD topological susceptibility at high temperature, $\\chi_t(T)$, provides an\nimportant input for the estimate of the axion abundance in the present\nUniverse. While the model independent determination of $\\chi_t(T)$ should be\npossible from the first principles using lattice QCD, existing methods fail at\nhigh temperature, since not only the probability that non-trivial topological\nsectors appear in the configuration generation process but also the local\ntopological fluctuations get strongly suppressed. We propose a novel method to\ncalculate the temperature dependence of topological susceptibility at high\ntemperature. A feasibility test is performed on a small lattice in the quenched\napproximation, and the results are compared with the prediction of the dilute\ninstanton gas approximation. It is found that the method works well especially\nat very high temperature and the result is consistent with the instanton\ncalculus down to $T\\sim 2\\, T_c$ within the statistical uncertainty.",
        "positive": "Tensor network simulation of QED on infinite lattices: learning from\n  (1+1)d, and prospects for (2+1)d: The simulation of lattice gauge theories with tensor network (TN) methods is\nbecoming increasingly fruitful. The vision is that such methods will,\neventually, be used to simulate theories in $(3+1)$ dimensions in regimes\ndifficult for other methods. So far, however, TN methods have mostly simulated\nlattice gauge theories in $(1+1)$ dimensions. The aim of this paper is to\nexplore the simulation of quantum electrodynamics (QED) on infinite lattices\nwith TNs, i.e., fermionic matter fields coupled to a $U(1)$ gauge field,\ndirectly in the thermodynamic limit. With this idea in mind we first consider a\ngauge-invariant iDMRG simulation of the Schwinger model -i.e., QED in\n$(1+1)d$-. After giving a precise description of the numerical method, we\nbenchmark our simulations by computing the substracted chiral condensate in the\ncontinuum, in good agreement with other approaches. Our simulations of the\nSchwinger model allow us to build intuition about how a simulation should\nproceed in $(2+1)$ dimensions. Based on this, we propose a variational ansatz\nusing infinite Projected Entangled Pair States (PEPS) to describe the ground\nstate of $(2+1)d$ QED. The ansatz includes $U(1)$ gauge symmetry at the level\nof the tensors, as well as fermionic (matter) and bosonic (gauge) degrees of\nfreedom both at the physical and virtual levels. We argue that all the\nnecessary ingredients for the simulation of $(2+1)d$ QED are, a priori, already\nin place, paving the way for future upcoming results."
    },
    {
        "anchor": "Lattice QCD calculation of the ${{B}_{(s)}\\to D_{(s)}^{*}\\ell\u03bd}$\n  form factors at zero recoil and implications for ${|V_{cb}|}$: We present results of a lattice QCD calculation of $B\\to D^*$ and $B_s\\to\nD_s^*$ axial vector matrix elements with both states at rest. These zero recoil\nmatrix elements provide the normalization necessary to infer a value for the\nCKM matrix element $|V_{cb}|$ from experimental measurements of $\\bar{B}^0\\to\nD^{*+}\\ell^-\\bar{\\nu}$ and $\\bar{B}^0_s\\to D_s^{*+}\\ell^-\\bar{\\nu}$ decay.\nResults are derived from correlation functions computed with highly improved\nstaggered quarks (HISQ) for light, strange, and charm quark propagators, and\nnonrelativistic QCD for the bottom quark propagator. The calculation of\ncorrelation functions employs MILC Collaboration ensembles over a range of\nthree lattice spacings. These gauge field configurations include sea quark\neffects of charm, strange, and equal-mass up and down quarks. We use ensembles\nwith physically light up and down quarks, as well as heavier values. Our main\nresults are $\\mathcal{F}^{B\\to D^*}(1)= 0.895\\pm\n0.010_{\\mathrm{stat}}\\pm{{0.024}_{\\mathrm{sys}}}$ and $\\mathcal{F}^{B_s\\to\nD_s^*}(1)= 0.883\\pm 0.010_{\\mathrm{stat}}\\pm{0.028_{\\mathrm{sys}}}$. We discuss\nthe consequences for $|V_{cb}|$ in light of recent investigations into the\nextrapolation of experimental data to zero recoil.",
        "positive": "QED-corrected Lellouch-L\u00fcscher formula for $K \\rightarrow \u03c0\u03c0$\n  decay: A precise SM prediction for the direct CP violation in the $K \\rightarrow\n\\pi\\pi$ decay process is of great importance in confronting experiments and\nconstraining new physics. The state-of-art lattice QCD study of this process\nwill soon achieve a precision that QED effects can no longer be neglected. The\ninclusion of QED in such calculations is planned, and the formalism to relate\nthe finite-volume matrix element obtained from these calculations to the\nphysical amplitude is underway. Here, we report on the progress towards an\nextension of the Lellouch-L\\\"uscher formalism in presence of QED, with the goal\nof enabling the extraction of physical amplitudes for the $K\\rightarrow \\pi\\pi$\nprocess with charged initial and/or final states."
    },
    {
        "anchor": "Taste breaking effects in scalar meson correlators: As a consistency check of the staggered-fermion fourth-root approximation, we\nanalyze the a_0 and f_0 correlators, including the effects of two-meson\ntaste-multiplet intermediate states. Rooted staggered chiral perturbation\ntheory describes the contributions from the pseudoscalar taste multiplets in\nterms of only a few low energy constants, which have all been previously\ndetermined by the MILC collaboration. In previous work one of us (Prelovsek)\nshowed that the two-meson ``bubble'' contributions could explain the observed\nanomalies in the lattice data for the isovector a_0 channel. In the present\nwork we extend this analysis to the f_0 channel. On a MILC collaboration\nlattice ensemble at 0.12 fm with 2+1 flavors of Asqtad-improved staggered\nfermions, we have made new measurements of correlators in both channels for a\nvariety of momenta. A fit to these correlators gives low energy constants that\nare reasonably consistent with previous determinations by the MILC\ncollaboration.}",
        "positive": "Excited States of U(1)$_{2+1}$ Lattice Gauge Theory from Monte Carlo\n  Hamiltonian: We address an old problem in lattice gauge theory - the computation of the\nspectrum and wave functions of excited states. Our method is based on the\nHamiltonian formulation of lattice gauge theory. As strategy, we propose to\nconstruct a stochastic basis of Bargmann link states, drawn from a physical\nprobability density distribution. Then we compute transition amplitudes between\nstochastic basis states. From a matrix of transition elements we extract energy\nspectra and wave functions. We apply this method to U(1)$_{2+1}$ lattice gauge\ntheory. We test the method by computing the energy spectrum, wave functions and\nthermodynamical functions of the electric Hamiltonian of this theory and\ncompare them with analytical results. We observe a reasonable scaling of\nenergies and wave functions in the variable of time. We also present first\nresults on a small lattice for the full Hamiltonian including the magnetic\nterm."
    },
    {
        "anchor": "Matching numerical simulations to continuum field theories: A lattice\n  renormalization study: The study of nonlinear phenomena in systems with many degrees of freedom\noften relies on complex numerical simulations. In trying to model realistic\nsituations, these systems may be coupled to an external environment which\ndrives their dynamics. For nonlinear field theories coupled to thermal (or\nquantum) baths, discrete lattice formulations must be dealt with extreme care\nif the results of the simulations are to be interpreted in the continuum limit.\nUsing techniques from renormalization theory, a self-consistent method is\npresented to match lattice results to continuum models. As an application,\nsymmetry restoration in $\\phi^4$ models is investigated.",
        "positive": "Simulating at Realistic Quark Masses: Pseudoscalar Decay Constants and\n  Chiral Logarithms: Due to improvements in computer performance and algorithms, the rapidly\nincreasing cost for unquenched Wilson-type fermions with lighter quarks has\nbeen ameliorated and new simulations are now possible. Here we present results\nusing two flavours of O(a)-improved Wilson fermions for meson decay constants\nat pseudoscalar masses down to 320MeV. Results are at several lattice spacings\ndown to about 0.07fm and include a non-perturbative determination of the\nrenormalisation constant. This enables us to attempt contact with (partially\nquenched) chiral perturbation theory."
    },
    {
        "anchor": "Flavor-singlet meson decay constants from $N_f=2+1+1$ twisted mass\n  lattice QCD: We present an improved analysis of our lattice data for the $\\eta$--$\\eta'$\nsystem, including a correction of the relevant correlation functions for\nresidual topological finite size effects and employing consistent chiral and\ncontinuum fits. From this analysis we update our physical results for the\nmasses $M_\\eta=557(11)_\\mathrm{stat}(03)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$ and\n$M_{\\eta'}=911(64)_\\mathrm{stat}(03)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$, as well\nas the mixing angle in the quark flavor basis\n$\\phi=38.8(2.2)_\\mathrm{stat}(2.4)_{\\chi\\mathrm{PT}}^\\circ$ in excellent\nagreement with other results from phenomenology. Similarly, we include an\nanalysis for the decay constant parameters, leading to\n$f_l=125(5)_\\mathrm{stat}(6)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$ and\n$f_s=178(4)_\\mathrm{stat}(1)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$. The second error\nreflects the uncertainty related to the chiral extrapolation. The data used for\nthis study has been generated on gauge ensembles provided by the European\nTwisted Mass Collaboration with $N_f=2+1+1$ dynamical flavors of Wilson twisted\nmass fermions. These ensembles cover a range of pion masses from\n$220\\,\\mathrm{MeV}$ to $500\\,\\mathrm{MeV}$ and three values of the lattice\nspacing. Combining our data with a prediction from chiral perturbation theory,\nwe give an estimate for the physical $\\eta,\\eta' \\rightarrow \\gamma\\gamma$\ndecay widths and the singly-virtual $\\eta,\\eta'\\rightarrow\\gamma\\gamma^*$\ntransition form factors in the limit of large momentum transfer.",
        "positive": "Monopoles of the Dirac type and color confinement in QCD -- First\n  results of SU(3) numerical simulations without gauge fixing: If non-Abelian gauge fields in $SU(3)$ QCD have a line-singularity leading to\nnon-commutativity with respect to successive partial-derivative operations, the\nnon-Abelian Bianchi identity is violated. The violation as an operator is shown\nto be equivalent to violation of Abelian-like Bianchi identities. Then there\nappear eight Abelian-like conserved magnetic monopole currents of the Dirac\ntype in $SU(3)$ QCD. Exact Abelian (but kinematical) symmetries appear in\nnon-Abelian $SU(3)$ QCD. Here we try to show the Abelian dual Meissner effect\ndue to the above Abelian-like monopoles are responsible for color confinement\nin $SU(3)$ QCD. If this picture is correct, the string tension of non-Abelian\nWilson loops is reproduced fully by that of the Abelian Wilson loops. This is\ncalled as perfect Abelian dominance. In this report, the perfect Abelian\ndominance is shown to exist with the help of the multilevel method but without\nintroducing additional smoothing techniques like partial gauge fixings,\nalthough lattice sizes studied are not large enough to study the infinite\nvolume limit. Perfect monopole dominance is also shown without any additional\ngauge fixing. Abelian electric fields are squeezed due to solenoidal monopole\ncurrents and the penetration length for an Abelian electric field of a single\ncolor is the same as that of non-Abelian electric field. The coherence length\nis also measured directly through the correlation of the monopole density and\nthe Polyakov loop pair. The Ginzburg-Landau parameter indicates that the vacuum\ntype is the weak type I (dual) superconductor. The results obtained above\nwithout any additional assumptions as well as more clear previous $SU(2)$\nresults seem to suggest strongly the above Abelian dual Meissner picture of\ncolor confinement mechanism."
    },
    {
        "anchor": "Dynamic critical phenomena from spectral functions on the lattice: We investigate spectral functions in the vicinity of the critical temperature\nof a second-order phase transition. Since critical phenomena in quantum field\ntheories are governed by classical dynamics, universal properties can be\ncomputed using real-time lattice simulations. For the example of a relativistic\nsingle-component scalar field theory in 2+1 dimensions, we compute the spectral\nfunction described by universal scaling functions and extract the dynamic\ncritical exponent z. Together with exactly known static properties of this\ntheory, we obtain a verification from first principles that the relativistic\ntheory is well described by the dynamic universality class of relaxational\nmodels with conserved density (Model C).",
        "positive": "Lattice Spacing Dependence of the First Order Phase Transition for\n  Dynamical Twisted Mass Fermions: Lattice QCD with Wilson fermions generically shows the phenomenon of a first\norder phase transition. We study the phase structure of lattice QCD using\nWilson twisted mass fermions and the Wilson plaquette gauge action are used in\na range of beta values where such a first order phase transition is observed.\nIn particular, we investigate the dependence of the first order phase\ntransition on the value of the lattice spacing. Using only data in one phase\nand neglecting possible problems arising from the phase transition we are able\nto perform a first scaling test for physical quantities using this action."
    },
    {
        "anchor": "Detecting and Mitigating Mode-Collapse for Flow-based Sampling of\n  Lattice Field Theories: We study the consequences of mode-collapse of normalizing flows in the\ncontext of lattice field theory. Normalizing flows allow for independent\nsampling. For this reason, it is hoped that they can avoid the tunneling\nproblem of local-update MCMC algorithms for multi-modal distributions. In this\nwork, we first point out that the tunneling problem is also present for\nnormalizing flows but is shifted from the sampling to the training phase of the\nalgorithm. Specifically, normalizing flows often suffer from mode-collapse for\nwhich the training process assigns vanishingly low probability mass to relevant\nmodes of the physical distribution. This may result in a significant bias when\nthe flow is used as a sampler in a Markov-Chain or with Importance Sampling. We\npropose a metric to quantify the degree of mode-collapse and derive a bound on\nthe resulting bias. Furthermore, we propose various mitigation strategies in\nparticular in the context of estimating thermodynamic observables, such as the\nfree energy.",
        "positive": "Exploratory study of the temperature dependence of magnetic vertices in\n  SU(2) Landau gauge Yang--Mills theory: Vertices describe the interactions between the fundamental degrees of\nfreedom, and are therefore of vital importance in many ab-initio descriptions\nof field theory, especially using functional methods. To this end, we present\nthe first lattice study of the thermal behavior of (minimal) Landau-gauge SU(2)\nYang--Mills three-point functions, i.e. three-gluon and ghost-gluon vertices.\nFocusing on the chromomagnetic sector, we find that the phase transition mainly\naffects the three-gluon vertex, while the ghost-gluon vertex is relatively\ninert."
    },
    {
        "anchor": "An Improved Action for Heavy Quarks: We extend the Fermilab method for heavy quarks to include all interactions of\ndimension six in the action. We discuss a subtlety in the power counting, which\nimplies that, for heavy quarks, certain interactions of dimension seven are\ncommensurate with some of those of dimension six. We then present tree-level\nmatching conditions obtained from calculating the Compton scattering amplitude\nfor (lattice) QCD. When the matching conditions have been applied, the improved\naction removes (tree-level) discretization errors of order $a^2\\bm{p}^3/m_Q$\nand $a^3\\bm{p}^3$.",
        "positive": "Lattice construction of Cho-Faddeev-Niemi decomposition and gauge\n  invariant monopole: We present the first implementation of the Cho--Faddeev--Niemi decomposition\nof the SU(2) Yang-Mills field on a lattice. Our construction retains the color\nsymmetry (global SU(2) gauge invariance) even after a new type of Maximally\nAbelian gauge, as explicitly demonstrated by numerical simulations. Moreover,\nwe propose a gauge-invariant definition of the magnetic monopole current using\nthis formulation and compare the new definition with the conventional one by\nDeGrand and Toussaint to exhibit its validity."
    },
    {
        "anchor": "Vortex Loops In The 3-d XY Model: We study the properties of vortex loops in the 3-d XY model. We find that the\nphase transition in this model is driven by the condensation of short loops\ninto percolating loops. Paper comes as a uuencoded compressed tar-file,\ncontaining the complete PostScript file. Total file approx. 220 Kb.",
        "positive": "Partially Twisted Boundary Conditions in Lattice Simulations: We use chiral perturbation theory to investigate twisted and partially\ntwisted boundary conditions which allow access to momenta other than integer\nmultiples of 2pi/L on a lattice with spatial volume L^3. For K -> pi pi decays\nwe show that the breaking of isospin symmetry by the twisted boundary\nconditions implies that the amplitudes cannot be determined in general. We find\nnumerical evidence for the result that the finite volume effects of the\nboundary conditions are exponentially suppressed for quantities without final\nstate interactions (meson masses and meson-to-vacuum matrix elements) in a\nsimulation with partial twisting on a sea of N_f=2 non-perturbatively improved\nWilson quarks."
    },
    {
        "anchor": "Baryon Masses from Lattice QCD: Beyond the Perturbative Chiral Regime: Consideration of the analytic properties of pion-induced baryon self-energies\nleads to new functional forms for the extrapolation of light baryon masses.\nThese functional forms reproduce the leading non-analytic behavior of chiral\nperturbation theory, the correct non-analytic behavior at the $N \\pi$ threshold\nand the appropriate heavy-quark limit. They involve only three unknown\nparameters, which may be obtained by fitting to lattice data. Recent dynamical\nfermion results from CP-PACS and UKQCD are extrapolated using these new\nfunctional forms. We also use these functions to probe the limit of\napplicability of chiral perturbation theory to the extrapolation of lattice QCD\nresults.",
        "positive": "Signature of a doubly charm tetraquark pole in $DD^*$ scattering on the\n  lattice: The doubly charm tetraquark with flavor $cc\\bar u\\bar d$ and isospin\n$I\\!=\\!0$ is investigated by calculating the $DD^*$ scattering amplitude with\nlattice QCD. The simulation is done on CLS ensembles with dynamical $u/d,s$\nquarks and $m_\\pi\\simeq 280~$MeV for two charm quark masses, one slightly\nlarger and one slightly lower than the physical value. The scattering\namplitudes for partial waves $l=0,1$ are extracted near-threshold via the\nL\\\"uscher's method by considering systems with total momenta\n$PL/(2\\pi)=0,1,\\sqrt{2},2$ on two spatial volumes. A virtual bound state pole\nin the $DD^*$ scattering amplitude with $l=0$ is found $9.9_{-7.1}^{+3.6}~$MeV\nbelow $DD^*$ threshold for the charm quark mass closer to the physical value.\nThis pole is likely related to the doubly charm tetraquark discovered by LHCb\nless than $1~$MeV below $D^0D^{*+}$ threshold. Future lattice simulations\ncloser to the continuum limit and physical quark masses would be valuable to\nestablish this connection systematically."
    },
    {
        "anchor": "Properties of P-vortex and monopole clusters in lattice SU(2) gauge\n  theory: We study the action and geometry of P-vortices, discriminating between the\npercolating and finite clusters. We also discuss the interrelation of the\nmonopoles and P-vortices. To define P-vortices we use both the direct maximal\ncenter projection and indirect maximal center projection. We find, in\nparticular, that the action density of the P-vortices in short clusters is\nsubstantially higher than in the percolating cluster. The surface of the\npercolating cluster appears random at short distances, with action density\ndepending on the shape.",
        "positive": "Light quark masses and pseudoscalar decay constants from Nf=2 twisted\n  mass QCD: We present the results of the lattice QCD calculation of the average up-down\nand strange quark masses and of the light meson pseudoscalar decay constants,\nrecently performed with Nf=2 dynamical fermions by the ETM Collaboration. The\nsimulation is carried out at a single value of the lattice spacing with the\ntwisted mass fermionic action at maximal twist, which guarantees automatic\nO(a)-improvement of the physical quantities. Quark masses are renormalized by\nimplementing the non perturbative RI-MOM renormalization procedure. Our results\nfor the light quark masses are m_{ud}^{MSbar}(2 Gev)=3.85 +- 0.12 +- 0.40 MeV,\nm_s^{MSbar}(2 Gev)=105 +- 3 +- 9 MeV and m_s/m_{ud}=27.3 +- 0.3 +- 1.2. We also\nobtain f_K=161.7 +- 1.2 +- 3.1 MeV and the ratio f_K/f_pi=1.227 +- 0.009 +-\n0.024. From this ratio, by using the experimental determination of Gamma(K ->\nmu {bar nu}_mu (gamma))/Gamma(pi -> mu {bar nu}_mu (gamma)) and the average\nvalue of |V_{ud}| from nuclear beta decays, we obtain |V_{us}|=0.2192(5)(45),\nin agreement with the determination from K_{l3} decays and the unitarity\nconstraint."
    },
    {
        "anchor": "On chiral spin symmetry and the QCD phase diagram: Recently, an approximate $SU(4)$ chiral spin-flavour symmetry was observed in\nmultiplet patterns of QCD meson correlation functions, in a temperature range\nabove the chiral crossover. This symmetry is larger than the chiral symmetry of\nmassless QCD, and can only arise effectively when colour-electric quark-gluon\ninteractions dynamically dominate the quantum effective action. At temperatures\nabout three times the crossover temperature, these patterns disappear again,\nindicating the screening of colour-electric interactions, and the expected\nchiral symmetry is recovered. In this contribution we collect independent\nevidence for such an intermediate temperature range, based on screening masses\nand the pion spectral function. Both kinds of observables behave\nnon-perturbatively in this window, with resonance-like peaks for the pion and\nits first excitation disappearing gradually with temperature. Using symmetry\narguments and the known behaviour of screening masses at small densities, we\ndiscuss how this chiral spin symmetric band continues into the QCD phase\ndiagram.",
        "positive": "Nuclear physics from QCD on lattice: We have presented a strategy to study nuclei and nuclear matters from first\nprinciples, namely, from QCD. We first compute nucleon-nucleon potentials\nnumerically in lattice QCD, and then use them to investigate properties of\nnuclei and nuclear matter by various methods developed in nuclear physics. As a\ndemonstration that this strategy works, mass and structure of ^4^He, ^16^O and\n^40^Ca, and equation of state of nuclear matters are determined with the\nlattice QCD induced two-nucleon potentials in a heavy quark region as an input.\nWe have found that these nuclei and the symmetric nuclear matter are bound at\none quark mass corresponding to the pseudo-scalar meson (pion) mass of 469 MeV\n(the octet baryon (nucleon) mass of 1161 MeV). The obtained binding energy per\nnucleon has a uniform mass-number A dependence which is consistent to the\nBethe-Weizsacker mass formula qualitatively. The present study demonstrates\nthat our strategy works well to investigate various properties of atomic nuclei\nand nuclear matter starting from QCD, without depending on models or\nexperimental information about the nuclear force."
    },
    {
        "anchor": "Pseudoscalar meson decay constants f_K, f_D and f_Ds, from Nf=2 twisted\n  mass Lattice QCD: We present the results of a lattice QCD calculation of the pseudoscalar meson\ndecay constants f_K, f_D and f_Ds, performed with N_f=2 dynamical fermions. The\nsimulation is carried out with the tree-level improved Symanzik gauge action\nand with the twisted mass fermionic action at maximal twist. With respect to\nour previous study (0709.4574 [hep-lat]), here we have analysed data at three\nvalues of the lattice spacing (a=0.10 fm, 0.09 fm, 0.07 fm) and performed the\ncontinuum limit, and we have included at a=0.09 fm data with a lighter quark\nmass (m_pi = 260 MeV) and a larger volume (L = 2.7 fm), thus having at each\nlattice spacing L >= 2.4 fm and m_pi*L >= 3.6. Our result for the kaon decay\nconstant is f_K=(157.5 +- 0.8|_{stat.} +- 3.3|_{syst.}) MeV and for the ratio\nf_K/f_pi=1.205 +- 0.006|_{stat.} +- 0.025|_{syst.}, in good agreement with the\nother N_f=2 and N_f=2+1 lattice calculations. For the D and D_s meson decay\nconstants we obtain f_D=(205 +- 7|_{stat.} +- 7|_{syst.}) MeV, in good\nagreement with the CLEO-c experimental measurement and with other recent N_f=2\nand N_f=2+1 lattice calculations, and f_{Ds}=(248 +- 3|_{stat.} +- 8|_{syst.})\nMeV that, instead, is 2.3 sigma below the CLEO-c/BABAR experimental average,\nconfirming the present tension between lattice calculations and experimental\nmeasurements.",
        "positive": "Transport Coefficients of Quark Gluon Plasma for Pure Gauge Models: The transport coefficients of quark gluon plasma are calculated on a lattice\n16**3X8, with the pure gauge models. Matsubara Green's functions of energy\nmomentum tensors have very large fluctuations and about a few million MC sweeps\nare needed to reduce the errors reasonably small in the case of the standard\naction. They are much suppressed if Iwasaki's improved action is employed.\nPreliminary results show that the transport coefficients roughly depend on the\ncoupling constant as a**(-3)(g) in the case of SU(2)."
    },
    {
        "anchor": "Radial and orbital excitations of static-light mesons: We present results for the spectrum of static-light mesons from Nf=2 lattice\nQCD. These results were obtained using all-to-all light quark propagators on an\nanisotropic lattice, yielding an improved signal resolution when compared to\nmore conventional lattice techniques. With a light quark mass close to the\nstrange quark, we have measured the splittings between the ground-state S-wave\nstatic-light meson and higher excitations. We attempt to identify the quantum\nnumbers of the excited states in the context of the reduced spatial symmetries\nof the lattice.",
        "positive": "Temperature dependence of the axial magnetic effect in two-color\n  quenched QCD: The Axial Magnetic Effect is the generation of an equilibrium dissipationless\nenergy flow of chiral fermions in the direction of the axial (chiral) magnetic\nfield. At finite temperature the dissipationless energy transfer may be\nrealized in the absence of any chemical potentials. We numerically study the\ntemperature behavior of the Axial Magnetic Effect in quenched SU(2) lattice\ngauge theory. We show that in the confinement (hadron) phase the effect is\nabsent. In the deconfinement transition region the conductivity quickly\nincreases, reaching the asymptotic $T^2$ behavior in a deep deconfinement\n(plasma) phase. Apart from an overall proportionality factor, our results\nqualitatively agree with theoretical predictions for the behavior of the energy\nflow as a function of temperature and strength of the axial magnetic field."
    },
    {
        "anchor": "Testing the fixed-point QCD action and the construction of chiral\n  currents: We present the first set of quenched QCD measurements using the recently\nparametrized fixed-point Dirac operator D^FP. We also give a general and\npractical construction of covariant densities and conserved currents for chiral\nlattice actions. The measurements include (a) hadron spectroscopy, (b)\ncorrections of small chiral deviations, (c) the renormalized quark condensate\nfrom finite-size scaling and, independently, spectroscopy, (d) the topological\nsusceptibility, (e) small eigenvalue distributions and random matrix theory,\nand (f) local chirality of near-zero modes and instanton-dominance.",
        "positive": "The Static Approximation to B Meson Mixing using Light Domain-Wall\n  Fermions: Perturbative Renormalization and Ground State Degeneracies: We discuss the theoretical input into the current RBC-UKQCD calculation of\n$f_{B_{d, s}}$ and $B_{B_{d, s}}$ using a smeared static heavy quark\npropagator, light domain-wall quarks and the Iwasaki gauge action. We present\nthe complete one-loop, mean-field improved matching of heavy-light current and\nfour-fermion lattice operators onto the static continuum theory renormalized in\n$\\bar{\\text{MS}}$(NDR). The large degeneracies present in a static calculation\nare addressed, and a method for extracting $f_B$ and $B_B$ using only box\nsources is described; implications for future calculations are discussed."
    },
    {
        "anchor": "The isovector axial form factor of the nucleon from lattice QCD: The isovector axial form factor of the nucleon plays a key role in\ninterpreting data from long-baseline neutrino oscillation experiments. We\nperform a lattice-QCD based calculation of this form factor, introducing a new\nmethod to directly extract its $z$-expansion from lattice correlators. Our\nfinal parametrization of the form factor, which extends up to spacelike\nvirtualities of $0.7\\,{\\rm GeV}^2$ with fully quantified uncertainties, agrees\nwith previous lattice calculations but is significantly less steep than\nneutrino-deuterium scattering data suggests.",
        "positive": "Annihilation diagram contribution to charmonium masses: In this work, we generate gauge configurations with $N_f=2$ dynamical charm\nquarks on anisotropic lattices. The mass shift of $1S$ and $1P$ charmonia owing\nto the charm quark annihilation effect can be investigated directly in a manner\nof unitary theory. The distillation method is adopted to treat the charm quark\nannihilation diagrams at a very precise level. For $1S$ charmonia, the charm\nquark annihilation effect almost does not change the $J/\\psi$ mass, but lifts\nthe $\\eta_c$ mass by approximately 3-4 MeV. For $1P$ charmonia, this effect\nresults in positive mass shifts of approximately 1 MeV for $\\chi_{c1}$ and\n$h_c$, but decreases the $\\chi_{c2}$ mass by approximately 3 MeV. We have not\nobtain a reliable result for the mass shift of $\\chi_{c0}$. In addition, it is\nobserved that the spin averaged mass of the spin-triplet $1P$ charmonia is in a\ngood agreement with the $h_c$, as expected by the non-relativistic quark model\nand measured by experiments."
    },
    {
        "anchor": "Nambu-Jona-Lasinio model with Wilson fermions: We present a lattice study of a Nambu Jona-Lasinio (NJL) model using Wilson\nfermions. Four fermion interactions are a natural part of several extensions of\nthe Standard Model, appearing as a low energy description of a more fundamental\ntheory. In models of dynamical electroweak symmetry breaking they are used to\nendow the Standard Model fermions with masses. In infrared conformal models\nthese interaction, when sufficiently strong, can alter the dynamics of the\nfixed point, turning the theory into a (near) conformal model with desirable\nfeatures for model building. As a first step toward the nonperturbative study\nof these models, we study the phase space of the ungauged NJL model.",
        "positive": "Lattice gauge theory in technicolor: The methods of lattice gauge theory may be applied to gauge theories besides\nQCD, in fact to any gauge group and any representation of matter fields (as\nlong as the coupling is not chiral). Such theories are useful for model\nbuilding beyond the Standard Model, for instance in technicolor models. We have\ncarried out Monte Carlo simulations of the SU(3) gauge theory with color sextet\nfermions. Our result for its discrete beta function indicate an infrared fixed\npoint that makes the theory conformal rather than confining. The lattice\ntheory's phase diagram shows no separation of chiral and confinement scales,\nmeasured when the quark mass is nonzero."
    },
    {
        "anchor": "Non-perturbative determination of anisotropy coefficients and pressure\n  gap at the deconfining transition of QCD: We propose a new non-perturbative method to compute derivatives of gauge\ncoupling constants with respect to anisotropic lattice spacings (anisotropy\ncoefficients). Our method is based on a precise measurement of the finite\ntemperature deconfining transition curve in the lattice coupling parameter\nspace extended to anisotropic lattices by applying the spectral density method.\nWe determine the anisotropy coefficients for the cases of SU(2) and SU(3) gauge\ntheories. A longstanding problem, when one uses the perturbative anisotropy\ncoefficients, is a non-vanishing pressure gap at the deconfining transition\npoint in the SU(3) gauge theory. Using our non-perturbative anisotropy\ncoefficients, we find that this problem is completely resolved.",
        "positive": "Lattice studies of hadrons with heavy flavors: I will discuss recent developments in lattice studies of hadrons composed of\nheavy quarks. I will mostly cover topics which are at a state of direct\ncomparison with experiment, but will also discuss new ideas and promising\ntechniques to aid future studies of lattice heavy quark physics."
    },
    {
        "anchor": "Isospin breaking effects due to the up-down mass difference in Lattice\n  QCD: We present a new method to evaluate with high precision isospin breaking\neffects due to the small mass difference between the up and down quarks using\nlattice QCD. Our proposal is applicable in principle to any hadronic observable\nwhich can be computed on the lattice. It is based on the expansion of the\npath-integral in powers of the small parameter md-mu. In this paper, we apply\nthis method to compute the leading isospin breaking effects for several\nphysical quantities of interest: the kaon meson masses, the kaon decay\nconstant, the form factors of semileptonic Kl3 decays and the neutron-proton\nmass splitting.",
        "positive": "Exactly massless fermions on the lattice: The salient features of the Ginsparg-Wilson fermion in topologically\nnontrivial background gauge fields are outlined. The R-invariance of the zero\nmodes, the indices and the index theorem on a finite lattice are illustrated.\nThe role of R in converting the nonlocal D_c into a sequence of highly local D\nis demonstrated."
    },
    {
        "anchor": "Charmonium spectral functions from 2+1 flavour lattice QCD: Finite temperature charmonium spectral functions in the pseudoscalar and\nvector channels are studied in lattice QCD with 2+1 flavours of dynamical\nWilson quarks, on fine isotropic lattices (with a lattice spacing of 0.057 fm),\nwith a non-physical pion mass of $m_{\\pi} \\approx$ 545 MeV. The highest\ntemperature studied is approximately $1.4 T_c$. Up to this temperature no\nsignificant variation of the spectral function is seen in the pseudoscalar\nchannel. The vector channel shows some temperature dependence, which seems to\nbe consistent with a temperature dependent low frequency peak related to heavy\nquark transport, plus a temperature independent term at \\omega>0. These results\nare in accord with previous calculations using the quenched approximation.",
        "positive": "Benchmarking quantum computers for real-time evolution of a $(1+1)$\n  field theory with error mitigation: Quantum computers open the possibility of performing real-time calculations\nfor quantum field theory scattering processes. We propose to use an index\naveraging the absolute value of the difference between the accurately\ncalculated Trotter evolution of site occupations and their actual measurements\non NISQ machines. The average is over all the qubits for a certain number of\nTrotter steps. We use this metric to quantify the progress made in successive\nstate-of-the-art machines and error-mitigation techniques. We illustrate the\nconcept with the transverse Ising model in one spatial dimension with four\nsites using three of IBM's quantum computers (Almaden, Boeblingen, and\nMelbourne). We discuss the size of the Trotter steps needed to achieve physics\ngoals. Using the proposed metric, we show that readout mitigation methods and\nRichardson extrapolations of mitigated measurements are very effective for\nspecific numbers of Trotter steps of a chosen size. This specific choice can be\napplied to other machines and noise mitigation methods. On the other hand, a\nreliable algorithmic mitigation would require a significantly larger number of\nsmaller Trotter steps."
    },
    {
        "anchor": "Light meson masses and decay constants in 2+1 flavour domain wall QCD: We present results for light meson masses and psedoscalar meson decay\nconstants in 2+1 flavour domain wall QCD with the DBW2 and Iwasaki gauge\nactions, using lattices with linear sizes in the range 1.6 to 2.2fm and $u$ and\n$d$ quark masses as low as one quarter of the strange quark mass. All data were\ngenerated on the QCDOC machines at the University of Edinburgh and Brookhaven\nNational Laboratory. Despite large residual masses and a limited number of sea\nquark mass values with which to perform chiral extrapolations, our results\nagree with experiment and scale within errors.",
        "positive": "Dissecting the $\u0394I= 1/2$ rule at large $N_c$: We study the scaling of kaon decay amplitudes with the number of colours,\n$N_c$, in a theory with four degenerate flavours, $N_f=4$. In this scenario,\ntwo current-current operators, $Q^\\pm$, mediate $\\Delta S=1$ transitions, such\nas the two isospin amplitudes of non-leptonic kaon decays for $K\\to\n(\\pi\\pi)_{I=0,2}$, $A_0$ and $A_2$. In particular, we concentrate on the\nsimpler $K\\to\\pi$ amplitudes, $A^\\pm$, mediated by these two operators. A\ndiagrammatic analysis of the large-$N_c$ scaling of these observables is\npresented, which demonstrates the anticorrelation of the leading ${\\mathcal\nO}(1/N_c)$ and ${\\mathcal O}(N_f/N_c^2)$ corrections in both amplitudes. Using\nour new $N_f=4$ and previous quenched data, we confirm this expectation and\nshow that these corrections are $naturally$ large and may be at the origin of\nthe $\\Delta I=1/2$ rule. The evidence for the latter is indirect, based on the\nmatching of the amplitudes to their prediction in Chiral Perturbation Theory,\nfrom which the LO low-energy couplings of the chiral weak Hamiltonian, $g^\\pm$,\ncan be determined. A NLO estimate of the $K \\to (\\pi\\pi)_{I=0,2}$ isospin\namplitudes can then be derived, which is in good agreement with the\nexperimental value."
    },
    {
        "anchor": "QCD quark condensate in external magnetic fields: We present a comprehensive analysis of the light condensates in QCD with\n1+1+1 sea quark flavors (with mass-degenerate light quarks of different\nelectric charges) at zero and nonzero temperatures of up to 190 MeV and\nexternal magnetic fields B<1 GeV^2/e. We employ stout smeared staggered\nfermions with physical quark masses and extrapolate the results to the\ncontinuum limit. At low temperatures we confirm the magnetic catalysis scenario\npredicted by many model calculations, while around the crossover the condensate\ndevelops a complex dependence on the external magnetic field, resulting in a\ndecrease of the transition temperature.",
        "positive": "Interactions of confining strings in SU(3) gluodynamics: We study the interaction energy of the confining strings in the static\nrectangular tetraquark system in SU(3) gluodynamics. Using a two-state\napproximation we calculate the energy eigenvalues and corresponding\neigenvectors of string states of different geometry. The interactions are\nstudied both for the co-aligned and for the counter-aligned parallel strings as\nthe functions of positions of the tetraquark constituents. We formulate a\nsimple soap-film model and show that with a good accuracy the string\ninteraction energy corresponding to the ground state of the tetraquark system\ncan be described by this soap-film model."
    },
    {
        "anchor": "Algebraic algorithm for the computation of one-loop Feynman diagrams in\n  lattice QCD with Wilson fermions: We describe an algebraic algorithm which allows to express every one-loop\nlattice integral with gluon or Wilson-fermion propagators in terms of a small\nnumber of basic constants which can be computed with arbitrary high precision.\nAlthough the presentation is restricted to four dimensions the technique can be\ngeneralized to every space dimension. Various examples are given, including the\none-loop self-energies of the quarks and gluons and the renormalization\nconstants for some dimension-three and dimension-four lattice operators. We\nalso give a method to express the lattice free propagator for Wilson fermions\nin coordinate space as a linear function of its values in eight points near the\norigin. This is an essential step in order to apply the recent methods of\nL\\\"{u}scher and Weisz to higher-loop integrals with fermions.",
        "positive": "Twisted reduction in large $N$ QCD with adjoint Wilson fermions: The twisted reduced model of large $N$ QCD with two adjoint Wilson fermions\nis studied numerically using the Hybrid Monte Carlo method. This is the\none-site model, whose large $N$ limit (large volume limit) is expected to be\nconformal or nearly conformal. The string tension calculated at $N$=289\napproaches zero as we decrease quark mass and the preliminary value of the mass\nanomalous dimension $\\gamma_*$ is close to one if we assume that the theory is\ngoverned by an infrared fixed point. We also discuss the twisted reduced model\nwith single adjoint Wilson fermion. The string tension remains finite as the\nquark mass decreases to zero, supporting that this is the confining theory."
    },
    {
        "anchor": "Lattice Results in Coulomb Gauge: We discuss recent numerical results obtained for gluon and ghost propagators\nin lattice Coulomb gauge and the status of the so-called Gribov-Zwanziger\nconfinement scenario in this gauge. Particular emphasis will be given to the\neigenvalue spectrum of the Faddeev-Popov matrix.",
        "positive": "Numerical Exploration of the RI/MOM Scheme Gauge Dependence: The gauge dependence of some fermion bilinear RI/MOM renormalization\nconstants is studied by comparing data which have been gauge-fixed in two\ndifferent realizations of the Landau gauge and in a generic covariant gauge.\nThe very good agreement between the various sets of results and the theory\nindicates that the numerical uncertainty induced by the lattice gauge-fixing\nprocedure is below the statistical errors of our data sample which is of the\norder of (1-1.5)%."
    },
    {
        "anchor": "Topology in high-$T$ QCD via staggered spectral projectors: We present preliminary lattice results for the topological susceptibility in\nhigh-$T$ $N_f=2+1$ QCD obtained discretizing this observable via spectral\nprojectors on eigenmodes of the staggered operator, and we compare them with\nthose obtained with the standard gluonic definition. The adoption of the\nspectral discretization is motivated by the large lattice artifacts affecting\nthe continuum scaling of the gluonic susceptibility at high $T$, related to the\nchoice of non-chiral fermions in the action.",
        "positive": "Hadronic vacuum polarization of the muon on 2+1+1-flavor HISQ ensembles:\n  an update: We give an update on the status of the Fermilab Lattice-HPQCD-MILC\ncalculation of the contribution to the muon's anomolous magnetic moment from\nthe light-quark, connected hadronic vacuum polarization. We present\npreliminary, blinded results in the intermediate window for this contribution,\n$a_{\\mu, \\textrm{W}}^{ll}$. The calculation is performed on $N_f =2+1+1$\nhighly-improved staggered quark (HISQ) ensembles from the MILC collaboration\nwith physical pion mass at four lattice spacings between 0.15 fm and 0.06 fm.\nWe also present preliminary results for a study of the two-pion contributions\nto the vector-current correlation function performed on the 0.15 fm ensemble\nwhere we see a factor of four improvement over traditional noise reduction\ntechniques."
    },
    {
        "anchor": "A Proposal for Simulating Chiral Fermions: We describe a method for evaluating chiral gauge theories that is not plagued\nby the doubling problem. To demonstrate the efficiency of the approach, we\napply our ideas to the chiral Schwinger model.",
        "positive": "Hadron Spectroscopy with Dynamical Wilson Fermions at beta=5.3: We present results from simulations of lattice QCD using two flavors of\ndynamical Wilson fermions at a lattice coupling $\\beta=5.3$ on $16^3 \\times 32$\nlattices at two hopping parameters, $\\kappa=0.1670$ and $0.1675$, leading to\n$m_\\pi \\approx 0.44$ and $0.33$ respectively. We show spectroscopy for S-wave\nhadrons and compare our results to other recent simulations with dynamical\nWilson fermions. (Complete postscript file can be obtained by anonymous ftp\nfrom ftp.scri.fsu.edu as file \"lat92.ps\" from directory \"pub/heller\".)"
    },
    {
        "anchor": "Spectroscopy with dynamical Chirally Improved quarks: We present recent results of our dynamical simulations with Chirally Improved\nfermions and report on new developments in the determination of excited\nlight-quark meson states using interpolators constructed by applying covariant\nderivatives on Jacobi-smeared quark sources within the framework of the\nvariational method.",
        "positive": "Relationship between the Euclidean and Lorentzian versions of the type\n  IIB matrix model: The type IIB matrix model was proposed as a non-perturbative formulation of\nsuperstring theory in 1996. We simulate a model that describes the late time\nbehavior of the IIB matrix model by applying the complex Langevin method to\novercome the sign problem. We clarify the relationship between the Euclidean\nand the Lorentzian versions of the type IIB matrix model in a recently\ndiscovered phase. By introducing a constraint, we obtain a model where the\nspacetime metric is Euclidean at early times, whereas it {\\it dynamically}\nbecomes Lorentzian at late times."
    },
    {
        "anchor": "Charmed baryon spectroscopy and light flavour symmetry from lattice QCD: We determine the ground state and first excited state masses of singly and\ndoubly charmed spin 1/2 and 3/2 baryons with positive and negative parity.\nConfigurations with $N_f=2+1$ non-perturbatively improved Wilson-clover\nfermions were employed, with the same quark action also being used for the\nvalence quarks, including the charm. The spectrum is calculated for pion masses\nin the range $M_\\pi \\sim 259-460$ MeV at a lattice spacing $a\\sim 0.075$ fm.\nFinite volume effects are studied comparing lattices with two different linear\nspatial extents ($1.8\\,{\\rm fm}$ and $2.4\\,{\\rm fm}$). The physical point is\napproached from the SU(3) limit keeping the flavour averaged light quark mass\nfixed. The baryon masses are extrapolated using expansions in the strange-light\nquark mass difference. Most particles fall into the expected SU(3) multiplets\nwith well constrained extrapolations, the exceptions having a possibly more\ncomplex internal structure. Overall agreement is found with experiment for the\nmasses and splittings of the singly charmed baryons. As part of the calculation\nan analysis of the lower lying charmonium, $D$ and $D_s$ spectra was performed\nin order to assess discretisation errors. The gross spectra are reproduced,\nincluding the $D^*_{s0}$, $D_{s1}$ and $D_1$ mesons, while at this single\nlattice spacing hyperfine splittings come out $10-20$ MeV too low.",
        "positive": "Effects of non-perturbatively improved dynamical fermions in UKQCD\n  simulations: We present results for QCD with 2 degenerate flavours of quark using a\nnon-perturbatively improved action on a lattice volume of $16^3\\times32$ where\nthe bare gauge coupling and bare dynamical quark mass have been chosen to\nmaintain a fixed physical lattice spacing and volume (1.71 fm). By comparing\nmeasurements from these matched ensembles, including quenched ones, we find\nevidence of dynamical quark effects on the short distance static potential, the\nscalar glueball mass and the topological susceptibility. There is little\nevidence of effects on the light hadron spectrum over the range of quark masses\nstudied ($m_{\\pi}/m_{\\rho}\\geq 0.60$)."
    },
    {
        "anchor": "Self-dual gauge fields, domain wall fermion zero modes and the\n  Kugo-Ojima confinement criterion: A new gauge fixing that imposes the U(1) real and quaternion real condition\non the correlator of domain wall fermion on the left wall and right wall is\nproposed. The method is applied to the calculation of the mass function, the\nQCD effective coupling and the charge form factor of the proton. By assuming\ntopological charge change $|Q|=1$, the charge form factor of the proton is\napproximately fitted by the dipole form factor.\n  The difference of the Kugo-Ojima color confinement parameter in quenched\nsimulation and in unquenched simulation is expected to be due to an anomaly\ncaused by the vertex of two fermion zero modes and the Bose ghost/gluon.",
        "positive": "Remarks on left-handed lattice fermions: We study whether applying lattice projectors on a vector-like Ginsparg-Wilson\nDirac operator is the only way to construct left-handed lattice fermions. Using\nRG transformations we derive an equation for the generating functional on the\nlattice, obtained by blocking from the continuum. We analyze how symmetries of\nthe continuum theory manifest themselves in this lattice generating functional\nand how anomalies emerge. The formalism is applied to left-handed continuum\nfermions and we derive two equations that characterize the corresponding\nlattice symmetries. To analyze possible solutions, we directly block a\nparameterized action for free continuum fermions to obtain the corresponding\nlattice action. Subsequently we study parameter values where the continuum\naction corresponds to left-handed fermions."
    },
    {
        "anchor": "Quark mass, scale and volume dependence of topological charge density\n  correlator in Lattice QCD: We study the two-point Topological Charge Density Correlator (TCDC) in\nlattice QCD with two degenerate flavours of naive Wilson fermions and\nunimproved Wilson gauge action at two values of lattice spacings and different\nvolumes, for a range of quark masses. Configurations are generated with DDHMC\nalgorithm and smoothed with HYP smearing. In order to shed light on the\nmechanisms leading to the observed suppression of topological susceptibility\nwith respect to the decreasing quark mass and decreasing volume, in this work,\nwe carry out a detailed study of the two-point TCDC. We have shown that, (1)\nthe TCDC is negative beyond a positive core and radius of the core shrinks as\nlattice spacing decreases, (2) as the volume decreases, the magnitude of the\ncontact term and the radius of the positive core decrease and the magnitude of\nthe negative peak increases resulting in the suppression of the topological\nsusceptibility as the volume decreases, (3) the contact term and radius of the\npositive core decrease with decreasing quark mass at a given lattice spacing\nand the negative peak increases with decreasing quark mass resulting in the\nsuppression of the topological susceptibility with decreasing quark mass, (4)\nincreasing levels of smearing suppresses the contact term and the negative peak\nkeeping the susceptibility intact and (5) both the contact term and the\nnegative peak diverge in nonintegrable fashion as lattice spacing decreases.",
        "positive": "Approximate actions for dynamical fermions: Recent developments and applications of approximate actions for full lattice\nQCD are described. We present first results based on the stochastic estimation\nof the fermion determinant on $12^3\\times 24$ configurations at $\\beta=5.2$."
    },
    {
        "anchor": "Flavour breaking effects in the pseudoscalar meson decay constants: The SU(3) flavour symmetry breaking expansion in up, down and strange quark\nmasses is extended from hadron masses to meson decay constants. This allows a\ndetermination of the ratio of kaon to pion decay constants in QCD. Furthermore\nwhen using partially quenched valence quarks the expansion is such that SU(2)\nisospin breaking effects can also be determined. It is found that the lowest\norder SU(3) flavour symmetry breaking expansion (or Gell-Mann-Okubo expansion)\nworks very well. Simulations are performed for 2+1 flavours of clover fermions\nat four lattice spacings.",
        "positive": "A generalized Ginsparg-Wilson relation: We show that, under certain general assumptions, any sensible lattice Dirac\noperator satisfies a generalized form of the Ginsparg-Wilson relation (GWR).\nThose assumptions, on the other hand, are mostly dictated by large momentum\nbehaviour considerations. We also show that all the desirable properties often\ndeduced from the standard GWR hold true of the general case as well; hence one\nhas, in fact, more freedom to modify the form of the lattice Dirac operator,\nwithout spoiling its nice properties. Our construction, a generalized\nGinsparg-Wilson relation (GGWR), is satisfied by some known proposals for the\nlattice Dirac operator. We discuss some of these examples, and also present a\nderivation of the GGWR in terms of a renormalization group transformation with\na blocking which is not diagonal in momentum space, but nevertheless commutes\nwith the Dirac operator."
    },
    {
        "anchor": "Adjoint ``Quarks'' and the Physics of Confinement: The quark-antiquark potential and the chromoelectric fields generated by\n``quarks'' in the adjoint representation of SU(2) color are analyzed in the\nscaling region of the theory. New results with interesting implications for our\nunderstanding of the confinement mechanism are presented. In particular, the\nformation of color-electric flux-tubes between adjoint quarks is demonstrated\nin four-dimensional SU(2) color. The flux-tubes for fundamental and adjoint\nrepresentation quarks are shown to have very similar cross-sections. This\nresult could imply that the QCD vacuum is dual to a type I superconductor.",
        "positive": "Form factors of the $D \\to \u03c0$ and $D \\to K$ semileptonic decays with\n  $N_f = 2$ twisted mass lattice QCD: We present lattice results for the vector and scalar form factors of the\nsemileptonic decays D -> \\pi \\ell \\nu_ell and D -> K \\ell \\nu_\\ell in the\nphysical range of values of squared four momentum transfer q^2, obtained with\nN_f=2 maximally twisted Wilson fermions simulated at three different lattice\nspacings (a ~ 0.102 fm, 0.086 fm, 0.068 fm) with pion masses as light as 270\nMeV and m_\\pi L \\gtrsim 4. The form factors are extracted using a double ratios\nstrategy, which allows a good statistical accuracy and is independent of the\nvector current renormalization constant. The chiral/continuum extrapolation is\nperformed through a simultaneous fit in the three variables (m_\\pi, q^2, a)\nusing HMChPT formulae with additional O(a^2) terms that parametrically account\nfor the lattice spacing dependence. Our results are in very good agreement with\nthe experimental data in the full q^2 range for both D -> \\pi \\ell \\nu_\\ell and\nD -> K \\ell \\nu_\\ell. At zero momentum transfer we obtain f^{D->pi}(0) =\n0.65(6)_{stat}(6)_{syst} and f^{D->K}(0) = 0.76(5)_{stat}(5)_{syst}, where the\nsystematic error does not include the effects of quenching the strange and the\ncharm quarks. Our findings are in good agreement with recent lattice\ncalculations at N_f = 2+1."
    },
    {
        "anchor": "Monopoles and string tension in SU(2) QCD: Monopole and photon contributions to abelian Wilson loops are calculated\nusing Monte-Carlo simulations of SU(2) QCD in the maximally abelian gauge. The\nstring tension is well reproduced only by monopole contributions, whereas\nphotons alone are responsible for the Coulomb coefficient of the abelian static\npotential.",
        "positive": "Probing QCD perturbation theory at high energies with continuum\n  extrapolated lattice data: Precision tests of QCD perturbation theory are not readily available from\nexperimental data. The main reasons are systematic uncertainties due to the\nconfinement of quarks and gluons, as well as kinematical constraints which\nlimit the accessible energy scales. We here show how continuum extrapolated\nlattice data may overcome such problems and provide excellent probes of\nrenormalized perturbation theory. This work corresponds to an essential step in\nthe ALPHA collaboration's project to determine the $\\Lambda$-parameter in\n3-flavour QCD. I explain the basic techniques used in the high energy regime,\nnamely the use of mass-independent renormalization schemes for the QCD coupling\nconstant in a finite Euclidean space time volume. When combined with finite\nsize techniques this allows one to iteratively step up the energy scale by\nfactors of 2, thereby quickly covering two orders of magnitude in scale. We may\nthen compare perturbation theory (with $\\beta$-functions available up to 3-loop\norder) to our non-perturbative data for a 1-parameter family of running\ncouplings. We conclude that a target precision of 3 percent for the\n$\\Lambda$-parameter requires non-perturbative data up to scales where\n$\\alpha_s\\approx 0.1$, whereas the apparent precision obtained from applying\nperturbation theory around $\\alpha_s \\approx 0.2$ can be misleading. This\nshould be taken as a general warning to practitioners of QCD perturbation\ntheory."
    },
    {
        "anchor": "Universal O(N) scaling and the chiral critical line in (2+1)-flavor QCD\n  with small chemical potentials: We show that for small values of the chemical potential the curvature of the\nphase transition line can be deduced from an analysis of scaling properties of\nthe chiral condensate and its susceptibilities. We make use of a recent\nanalysis of the magnetic equation of state in (2+1)-flavor QCD where a\nconnection between the QCD parameters and the universal scaling fields could be\nestablished. The remaining dependence of the reduced temperature on the\nchemical potential can be fixed by an analysis of a mixed susceptibility,\nobtained from a derivative with respect to quark mass and chemical potential.\nWe extract this dependence which describes the curvature of the phase\ntransition line, at two values of the cut-off, $aT=1/4$ and $1/8$. We find that\ncut-off effects are small for the curvature parameter and determine the\ntransition line in the chiral limit to leading order in the light quark\nchemical potential. We obtain $T_c(\\mu_B)/T_c(0) = 1 - 0.00656(66) (\\mu_B/T)^2\n+{\\cal O}(\\mu_B^4)$.",
        "positive": "Large $N$ reduction in deformed Yang-Mills theories: We explore, at the nonperturbative level, the large $N$ equivalence between\nordinary $SU(N)$ Yang-Mills theory on $\\mathbb{R}^4$ and on $\\mathbb{R}^3\n\\times S^1$ with double-trace deformations. In particular, we compare the\nvalues of the $0^{++}$ glueball mass obtained in both sides of the equivalence."
    },
    {
        "anchor": "3-point functions from twisted mass lattice QCD at small quark masses: We show at the example of the matrix element between pion states of a\ntwist-2, non-singlet operator that Wilson twisted mass fermions allow to\ncompute this phenomenologically relevant quantitiy at small pseudo scalar\nmasses of O(270 MeV). In the quenched approximation, we investigate the scaling\nbehaviour of this observable that is derived from a 3-point function by\napplying two definitions of the critical mass and find a scaling compatible\nwith the expected O(a^2) behaviour in both cases. A combined continuum\nextrapolations allows to obtain reliable results at small pion masses, which\npreviously could not be explored by lattice QCD simulations.",
        "positive": "London relation and fluxoid quantization for monopole currents in U(1)\n  lattice gauge theory: We explore the analogy between quark confinement and the Meissner effect in\nsuperconductors. We measure the response of color-magnetic \"supercurrents\" from\nDirac magnetic monopoles to the presence of a static quark-antiquark pair in\nfour dimensional U(1) lattice gauge theory. Our results indicate that in the\nconfined phase these currents screen the color-electric flux due to the quarks\nin an electric analogy of the Meisner effect. We show that U(1) lattice guage\ntheory obeys both a dual London equation and an electric fluxoid quantization\ncondition."
    },
    {
        "anchor": "Krylov space solvers for shifted linear systems: We investigate the application of Krylov space methods to the solution of\nshifted linear systems of the form (A+\\sigma) x - b = 0 for several values of\n\\sigma simultaneously, using only as many matrix-vector operations as the\nsolution of a single system requires. We find a suitable description of the\nproblem, allowing us to understand known algorithms in a common framework and\ndeveloping shifted methods basing on short recurrence methods, most notably the\nCG and the BiCGstab solvers. The convergence properties of these shifted\nsolvers are well understood and the derivation of other shifted solvers is\neasily possible. The application of these methods to quark propagator\ncalculations in quenched QCD using Wilson and Clover fermions is discussed and\nnumerical examples in this framework are presented. With the shifted CG method\nan optimal algorithm for staggered fermions is available.",
        "positive": "How much do charm sea quarks affect the charmonium spectrum?: The properties of charmonium states are or will be intensively studied by the\nB-factories Belle II and BESIII, the LHCb and PANDA experiments and at a future\nSuper-c-tau Factory. Precise lattice calculations provide valuable input and\nseveral results have been obtained by simulating up, down and strange quarks in\nthe sea. We investigate the impact of a charm quark in the sea on the\ncharmonium spectrum, the renormalization group invariant charm-quark mass and\nthe scalar charm-quark content of charmonium. The latter is obtained by the\ndirect computation of the mass-derivatives of the charmonium masses. We do this\ninvestigation in a model, QCD with two degenerate charm quarks. The absence of\nlight quarks allows us to reach very small lattice spacings down to 0.023 fm.\nBy comparing to pure gauge theory we find that charm quarks in the sea affect\nthe hyperfine splitting at a level below 2%. The most significant effects are\n5% in the quark mass and 3% in the value of the charm quark content of the\neta_c meson. Given that we simulate two charm quarks these estimates are upper\nbounds for the contribution of a single charm quark. We show that lattice\nspacings <0.06 fm are needed for safe continuum extrapolations of the\ncharmonium spectrum with O(a) improved Wilson quarks. A useful relation for the\nprojection to the desired parity of operators in two-point functions computed\nwith twisted mass fermions is proven."
    },
    {
        "anchor": "Z2 electric strings and center vortices in SU(2) lattice gauge theory: We study the representations of SU(2) lattice gauge theory in terms of sums\nover the worldsheets of center vortices and Z2 electric strings, i.e. surfaces\nwhich open on the Wilson loop. It is shown that in contrast to center vortices\nthe density of electric Z2 strings diverges in the continuum limit of the\ntheory independently of the gauge fixing, however, their contribution to the\nWilson loop yields physical string tension due to non-positivity of their\nstatistical weight in the path integral, which is in turn related to the\npresence of Z2 topological monopoles in the theory.",
        "positive": "First results in QCD with 2+1 light flavors using the fixed-point action: This is a progress report on 2+1 flavor simulation with the FP action on a\nlattice with spatial size L=1.2fm. Since m_{ud} is quite small in our\nsimulation we are in the delta regime for the two light flavors where the low\nlying excitations are described by a quantum mechanical rotator. From here we\nextract the low energy constant F. We also measure the AWI mass and present\nresults on numerical issues like low-mode averaging and autocorrelation times."
    },
    {
        "anchor": "On the phase structure of twisted mass lattice QCD: The introduction of a chirally twisted mass term has been proposed as an\nattractive approach to O(a) improvement of Quantum Chromodynamics with Wilson\nfermions on a lattice. For numerical simulation projects it is important to\nknow the phase structure of the theory in the region of small quark masses. We\nstudy this question in the framework of chiral perturbation theory.\nGeneralizing the analysis of Sharpe and Singleton we find extensions of normal\nand Aoki phase scenarios and a possible new phase with spontaneous breakdown of\nchiral symmetry to a discrete $Z_2$.",
        "positive": "The pion form factor from lattice QCD with two dynamical flavours: We compute the electromagnetic form factor of the pion using\nnon-perturbatively O(a) improved Wilson fermions. The calculations are done for\na wide range of pion masses and lattice spacings. We check for finite size\neffects by repeating some of the measurements on smaller lattices. The large\nnumber of lattice parameters we use allows us to extrapolate to the physical\npoint. For the square of the charge radius we find <r^2>=0.441(20) fm^2, in\ngood agreement with experiment."
    },
    {
        "anchor": "Search for Fermion Actions on Hyperdiamond Lattices: Fermions moving in a two-dimensional honeycomb lattice (graphene) have, at\nlow energies, chiral symmetry. Generalizing this construction to four\ndimensions potentially provides fermions with chiral symmetry and only the\nminimal fermion doubling demanded by the Nielsen-Ninomiya no-go theorem. The\npractical usefulness of such fermions hinges on whether the action has a\nnecessary set of discrete symmetries of the lattice. If this is the case, one\navoids the generation of dimension three and four operators which require fine\ntuning. We construct hyperdiamond lattice actions with enough symmetries to\nexclude fine tuning; however, they produce multiple doublings. The limit where\nthe actions exhibit minimal doubling does not possess the requisite symmetry.",
        "positive": "High Temperature Confinement in SU(N) Gauge Theories: SU(N) gauge theories, extended with adjoint fermions having periodic boundary\nconditions, are confining at high temperature for sufficiently light fermion\nmass m. Lattice simulations indicate that this confining region is smoothly\nconnected to the confining region of low-temperature pure SU(N) gauge theory.\nIn the high temperature confining region, the one-loop effective potential for\nPolyakov loops has a Z(N)-symmetric confining minimum. String tensions\nassociated with Polyakov loops are smooth functions of m/T. In the magnetic\nsector, the Polyakov loop plays a role similar to a Higgs field, leading to a\nbreaking of SU(N) to U(1)^{N-1}. This is turn yields an effective theory where\nmagnetic monopoles give rise to string tensions for spatial Wilson loops. These\nstring tensions are calculable semiclassically. There are many analytical\npredictions for the high-temperature region that can be tested by lattice\nsimulations, but lattice work will be crucial for exploring the crossover from\nthis region to the low-temperature confining behavior of pure gauge theories."
    },
    {
        "anchor": "QCD String Spectrum 2002: Results from a comprehensive new analysis on the excitation spectrum of the\nQCD string are presented. A rapid onset of string formation is observed in the\nspectrum on a length scale of 2 fm, with Dirichlet boundary conditions. The\ncrossover from the short distance spectrum towards string excitations and an\nobserved fine structure in the 1--3 fm range are related to effective string\ntheory. The deficiencies of the Nambu-Goto bosonic string model in describing\nthe observed spectrum are briefly discussed.",
        "positive": "Hedgehogs in Wilson loops and phase transition in SU(2) Yang-Mills\n  theory: We suggest that the gauge-invariant hedgehoglike structures in the Wilson\nloops are physically interesting degrees of freedom in the Yang--Mills theory.\nThe trajectories of these ``hedgehog loops'' are closed curves corresponding to\ncenter-valued (untraced) Wilson loops and are characterized by the center\ncharge and winding number. We show numerically in the SU(2) Yang--Mills theory\nthat the density of hedgehog structures in the thermal Wilson--Polyakov line is\nvery sensitive to the finite-temperature phase transition. The (additively\nnormalized) hedgehog line density behaves like an order parameter: the density\nis almost independent of the temperature in the confinement phase and changes\nsubstantially as the system enters the deconfinement phase. In particular, our\nresults suggest that the (static) hedgehog lines may be relevant degrees of\nfreedom around the deconfinement transition and thus affect evolution of the\nquark-gluon plasma in high-energy heavy-ion collisions."
    },
    {
        "anchor": "Quantum fluctuations of the color flux tube: The quantum fluctuations of the flux tube joining two static sources in the\nconfining phase of a lattice gauge theory are described by an effective string\ntheory. The predictions of the latter for ratios of Wilson loops of equal\nperimeter do not contain any free parameters, and can be computed exactly for\nlarge Wilson loops. We compare these predictions with numerical results in 3D\n$Z_2$ gauge theory, finding complete agreement.",
        "positive": "Diquark Condensation in Dense Matter - A Lattice Perspective: We review efforts to study, using the methods of lattice field theory, the\nphenomenon of diquark condensation via BCS pairing at a Fermi surface, which\nhas been proposed as a mechanism for color superconductivity in dense quark\nmatter. The particular models studied are the Gross-Neveu model and SU(2)\nlattice gauge theory; in both cases evidence for superfluidity at high density\nis presented. The behaviour expected for quarks in both fundamental and adjoint\nrepresentations of SU(2) is contrasted."
    },
    {
        "anchor": "Pion Transition Form Factor from Twisted-Mass Lattice QCD and the\n  Hadronic Light-by-Light $\u03c0^0$-pole Contribution to the Muon $g-2$: The neutral pion generates the leading pole contribution to the hadronic\nlight-by-light tensor, which is given in terms of the nonperturbative\ntransition form factor $\\mathcal{F}_{\\pi^0\\gamma\\gamma}(q_1^2,q_2^2)$. Here we\npresent an ab-initio lattice calculation of this quantity in the continuum and\nat the physical point using twisted-mass lattice QCD. We report our results for\nthe transition form factor parameterized using a model-independent conformal\nexpansion valid for arbitrary space-like kinematics and compare it with\nexperimental measurements of the single-virtual form factor, the two-photon\ndecay width, and the slope parameter. We then use the transition form factors\nto compute the pion-pole contribution to the hadronic light-by-light scattering\nin the muon $g-2$, finding $a_\\mu^{\\pi^0\\text{-pole}} = 56.7(3.2) \\times\n10^{-11}$.",
        "positive": "Status and prospects for the calculation of hadron structure from\n  lattice QCD: Lattice QCD calculations of hadron structure are a valuable complement to\nmany experimental programs as well as an indispensable tool to understand the\ndynamics of QCD. I present a focused review of a few representative topics\nchosen to illustrate both the challenges and advances of our community: the\nmomentum fraction, axial charge and charge radius of the nucleon. I will\ndiscuss the current status of these calculations and speculate on the prospects\nfor accurate calculations of hadron structure from lattice QCD."
    },
    {
        "anchor": "Toward a precise determination of Tc with 2+1 flavors of quarks: We present a status report on a new high statistics study of the high\ntemperature transition in full QCD at zero chemical potential. Our simulations\nuse both improved asqtad and p4 staggered quarks on lattices with a temporal\nextent N_t = 8 and light quark masses approximately one tenth the strange quark\nmass. In this report we describe the setup of our calculations and present a\npreliminary analysis of a variety of sources of systematic error and ambiguity\nin the determination of the crossover temperature. We propose to present our\nfinal analysis with double the current statistics. These calculations were\ncarried out on the IBM BlueGene/L supercomputer at Lawrence Livermore National\nLaboratory.",
        "positive": "Analytical relation between quark confinement and chiral symmetry\n  breaking in odd-number lattice QCD: To clarify the relation between confinement and chiral symmetry breaking in\nQCD, we consider a temporally odd-number lattice, with the temporal lattice\nsize $N_t$ being odd. We here use an ordinary square lattice with the normal\n(nontwisted) periodic boundary condition for link-variables in the temporal\ndirection. By considering ${\\rm Tr} (\\hat{U}_4\\hat{\\not D}^{N_t-1})$, we\nanalytically derive a gauge-invariant relation between the Polyakov loop\n$\\langle L_P \\rangle$ and the Dirac eigenvalues $\\lambda_n$ in QCD, i.e.,\n$\\langle L_P \\rangle \\propto \\sum_n \\lambda_n^{N_t -1} \\langle n|\\hat U_4|n\n\\rangle$, which is a Dirac spectral representation of the Polyakov loop in\nterms of Dirac eigenmodes $|n\\rangle$. Owing to the factor $\\lambda_n^{N_t -1}$\nin the Dirac spectral sum, this relation generally indicates fairly small\ncontribution of low-lying Dirac modes to the Polyakov loop, while the low-lying\nDirac modes are essential for chiral symmetry breaking. Also in lattice QCD\ncalculations in both confined and deconfined phases, we numerically confirm the\nanalytical relation, non-zero finiteness of $\\langle n|\\hat U_4|n \\rangle$ for\neach Dirac mode, and negligibly small contribution from low-lying Dirac modes\nto the Polyakov loop, i.e., the Polyakov loop is almost unchanged even by\nremoving low-lying Dirac-mode contribution from the QCD vacuum generated by\nlattice QCD simulations. We thus conclude that low-lying Dirac modes are not\nessential modes for confinement, which indicates no direct one-to-one\ncorrespondence between confinement and chiral symmetry breaking in QCD."
    },
    {
        "anchor": "A high-statistics study of the nucleon EM form factors, axial charge and\n  quark momentum fraction: We present updated results for the nucleon axial charge and electromagnetic\n(EM) form factors, which include a significant increase in statistics for all\nensembles (up to 4000 measurements), as well as the addition of ensembles with\npion masses down to $m_\\pi\\sim195$ MeV. We also present results for the average\nquark momentum fraction. The new data allows us to perform a thorough study of\nthe systematic effects encountered in the lattice extraction. We concentrate on\nsystematic effects due to excited-state contaminations for each of the\nquantities, which we check using several different time separations between the\noperators at the source and sink through a comparison of plateau fits and the\nsummed operator insertion method (which provides a mechanism to suppress the\nexcited-state contamination). We confirm our earlier finding that a reliable\nextraction of the axial charge must be based on a method which eliminates\nexcited-state contaminations. Similar conclusions apply to our EM form factor\ncalculations . The measurements are calculated using the CLS ensembles with\nnon-perturbatively O(a) improved Wilson fermions in $N_f=2$ QCD.",
        "positive": "Comparing the R algorithm and RHMC for staggered fermions: The R algorithm is widely used for simulating two flavours of dynamical\nstaggered fermions. We give a simple proof that the algorithm converges to the\ndesired probability distribution to within O(dt^2) errors, but show that the\nrelevant expansion parameter is (dt/m)^2, m being the quark mass. The Rational\nHybrid Monte Carlo (RHMC) algorithm provides an exact (i.e., has no step size\nerrors) alternative for simulating the square root of the staggered Dirac\noperator. We propose using it to test the validity of the R algorithm for\nsimulations carried out with dt m."
    },
    {
        "anchor": "Flavor-singlet mesons in N_f=2+1 QCD with dynamical overlap quarks: We report on our study of flavor-singlet mesons in three-flavor QCD with\ndynamical overlap quarks. Gauge ensembles are generated on a 16^3 x 48 lattice\nat a lattice spacing of 0.10 fm with the strange quark masses around its\nphysical value m_s,phys and up and down quark masses down to m_s,phys/5.\nConnected and disconnected meson correlators are calculated using the\nall-to-all quark propagator. We present our preliminary results on the spectrum\nof flavor-singlet pseudoscalar and vector mesons.",
        "positive": "High Statistics Analysis using Anisotropic Clover Lattices: (III)\n  Baryon-Baryon Interactions: Low-energy baryon-baryon interactions are calculated in a high-statistics\nlattice QCD study on a single ensemble of anisotropic clover gauge-field\nconfigurations at a pion mass of m_\\pi ~ 390 MeV, a spatial volume of L^3 ~\n(2.5 fm)^3, and a spatial lattice spacing of b~0.123 fm. L\\\"uscher's method is\nused to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering\nphase shifts at one momentum from the one- and two-baryon ground-state energies\nin the lattice volume. The isospin-3/2 N\\Sigma interactions are found to be\nhighly spin-dependent, and the interaction in the ^3S_1 channel is found to be\nstrong. In contrast, the N\\Lambda interactions are found to be\nspin-independent, within the uncertainties of the calculation, consistent with\nthe absence of one-pion-exchange. The only channel for which a negative\nenergy-shift is found is \\Lambda\\Lambda, indicating that the \\Lambda\\Lambda\ninteraction is attractive, as anticipated from model-dependent discussions\nregarding the H-dibaryon. The NN scattering lengths are found to be small,\nclearly indicating the absence of any fine-tuning in the NN-sector at this pion\nmass. This is consistent with our previous Lattice QCD calculation of NN\ninteractions. The behavior of the signal-to-noise ratio in the baryon-baryon\ncorrelation functions, and in the ratio of correlation functions that yields\nthe ground-state energy splitting is explored. In particular, focus is placed\non the window of time slices for which the signal-to-noise ratio does not\ndegrade exponentially, as this provides the opportunity to extract quantitative\ninformation about multi-baryon systems."
    },
    {
        "anchor": "Quark Mass Dependence of Nucleon Properties and Extrapolation from\n  Lattice QCD: We summarize developments concerning the quark mass dependence of nucleon\nmagnetic moments and the axial-vector coupling constant g_A. The aim is to\nexplore the feasibility of chiral effective field theory methods for the\nextrapolation of lattice QCD results, from the relatively large quark masses\nthat can be handled in such computations down to the physically relevant range.",
        "positive": "Noisy Monte Carlo Algorithm: We present an exact Monte Carlo algorithm designed to sample theories where\nthe energy is a sum of many couplings of decreasing strength. The algorithm\navoids the computation of almost all non-leading terms. Its use is illustrated\nby simulating SU(2) lattice gauge theory with a 5-loop improved action. A new\napproach for dynamical fermion simulations is proposed."
    },
    {
        "anchor": "Progress in Lattice Gauge Theory: I summarize recent progress in lattice gauge theory, with particular emphasis\non results from numerical simulations. A major success has been the\ndetermination of the light hadron spectrum in the quenched approximation with\nsufficient accuracy to expose statistically significant disagreements with the\nexperimental spectrum. The differences are, however, fairly small, $\\sim\n5-10%$. The data are also accurate enough to show evidence for artifacts of\nquenching predicted by chiral perturbation theory. I give an update on results\nfor light quark masses, the kaon B-parameter, and the decay constants and\nB-parameters of heavy-light mesons. Most of these are known in the quenched\napproximation to $\\sim 10%$ accuracy or better, and preliminary estimates of\nquenching errors are of comparable size. One exception is the light quark\nmasses, for which the quenching errors appear to be larger. I discuss the\ncomputational requirements for simulations of QCD with all approximations\ncontrolled, and argue that they will likely begin once computers sustain about\n10 Teraflops. This is 30-40 times faster than present state-of-the-art\nmachines. This estimate assumes that improvements in the discretization of\nlattice fermions are sufficient to allow continuum extrapolations to be made\nwith a minimum lattice spacing of $\\approx 0.1 $fm. I review results obtained\nwith improved discretizations and conclude that they satisfy this requirement\nin most cases. Examples of successful improvement include the calculation of\nthe glueball spectrum and excited heavy-quark potentials in pure Yang-Mills\ntheory. Finally, I discuss recent developments which may allow simulations of\nQCD with full chiral symmetry even at finite lattice spacing.",
        "positive": "Leading isospin breaking effects on the lattice: We present a method to evaluate on the lattice the leading isospin breaking\neffects due to both the small mass difference between the up and down quarks\nand the QED interaction. Our proposal is applicable in principle to any QCD+QED\ngauge invariant hadronic observable which can be computed on the lattice. It is\nbased on the expansion of the path-integral in powers of the small parameters\n(m_d - m_u)/Lambda_{QCD} and alpha_{em}, where m_f is the renormalized quark\nmass and alpha_{em} the renormalized fine structure constant. In this paper we\ndiscuss in detail the general strategy of the method and the conventional,\nalthough arbitrary, separation of QCD from QED isospin breaking corrections. We\nobtain results for the pion mass splitting, M_{pi+}^2-M_{pi0}^2= 1.44(13)(16) x\n10^3 MeV^2, for the Dashen's theorem breaking parameter epsilon_{gamma}=\n0.79(18)(18), for the light quark masses, [m_d - m_u](MSbar,2 GeV)= 2.39(8)(17)\nMeV, [m_u / m_d](MSbar,2 GeV)= 0.50(2)(3) and for the flavour symmetry breaking\nparameters R and Q. We also update our previous results for the QCD isospin\nbreaking corrections to the Kl2 decay rate and for the QCD contribution to the\nneutron-proton mass splitting."
    },
    {
        "anchor": "Continuum Limit of $B_K$ from 2+1 Flavor Domain Wall QCD: We determine the neutral kaon mixing matrix element $B_K$ in the continuum\nlimit with 2+1 flavors of domain wall fermions, using the Iwasaki gauge action\nat two different lattice spacings. These lattice fermions have near exact\nchiral symmetry and therefore avoid artificial lattice operator mixing.\n  We introduce a significant improvement to the conventional NPR method in\nwhich the bare matrix elements are renormalized non-perturbatively in the\nRI-MOM scheme and are then converted into the MSbar scheme using continuum\nperturbation theory. In addition to RI-MOM, we introduce and implement four\nnon-exceptional intermediate momentum schemes that suppress infrared\nnon-perturbative uncertainties in the renormalization procedure. We compute the\nconversion factors relating the matrix elements in this family of RI-SMOM\nschemes and MSbar at one-loop order. Comparison of the results obtained using\nthese different intermediate schemes allows for a more reliable estimate of the\nunknown higher-order contributions and hence for a correspondingly more robust\nestimate of the systematic error. We also apply a recently proposed approach in\nwhich twisted boundary conditions are used to control the Symanzik expansion\nfor off-shell vertex functions leading to a better control of the\nrenormalization in the continuum limit.\n  We control chiral extrapolation errors by considering both the NLO SU(2)\nchiral effective theory, and an analytic mass expansion. We obtain\n$B_K^{\\msbar}(3 GeV) = 0.529(5)_{stat}(15)_\\chi(2)_{FV}(11)_{NPR}$. This\ncorresponds to $\\hat{B}_K = 0.749(7)_{stat}(21)_\\chi(3)_{FV}(15)_{NPR}$. Adding\nall sources of error in quadrature we obtain $\\hat{B}_K =\n0.749(27)_{combined}$, with an overall combined error of 3.6%.",
        "positive": "Near-Physical Point Lattice Calculation of Isospin-Breaking Corrections\n  to $K_{\\ell2}/\u03c0_{\\ell2}$: In recent years, lattice determinations of non-perturbative quantities such\nas $f_K$ and $f_\\pi$, which are relevant for $V_{us}$ and $V_{ud}$, have\nreached an impressive precision of $\\mathcal{O}(1\\%)$ or better. To make\nfurther progress, electromagnetic and strong isospin breaking effects must be\nincluded in lattice QCD simulations.\n  We present the status of the RBC/UKQCD lattice calculation of\nisospin-breaking corrections to light meson leptonic decays. This computation\nis performed in a (2+1)-flavor QCD simulation using Domain Wall Fermions with\nnear-physical quark masses. The isospin-breaking effects are implemented via a\nperturbative expansion of the action in $\\alpha$ and $(m_u-m_d)$. In this\ncalculation, we work in the electro-quenched approximation and the photons are\nimplemented in the Feynman gauge and $\\text{QED}_\\text{L}$ formulation."
    },
    {
        "anchor": "Quenched QCD with domain wall fermions: We report on simulations of quenched QCD using domain wall fermions, where we\nfocus on basic questions about the formalism and its ability to produce\nexpected low energy hadronic physics for light quarks. The work reported here\nis on quenched $8^3 \\times 32$ lattices at $\\beta = 5.7$ and 5.85, using values\nfor the length of the fifth dimension between 10 and 48. We report results for\nparameter choices which lead to the desired number of flavors, a study of\nundamped modes in the extra dimension and hadron masses.",
        "positive": "The nature of the continuum limit in the 2D $RP^2$ gauge model: The RP(2) gauge model is studied in 2D. We use Monte-Carlo renormalization\ntechniques for blocking the mean spin-spin interaction, <A>, and the mean gauge\nfield plaquette, <P>. The presence of the O(3) renormalized trajectory is\nverified and is consistent with the known three-loop beta-function. The\nfirst-order `vorticity' transition observed by Solomon et al. is confirmed, and\nthe location of the terminating critical point is established. New scaling\nflows in (<A>,<P>) are observed associated with a large exponent kappa in the\nrange 4~5. The scaling flows give rise to a strong cross-over effect between\nregions of high and low vorticity and are likely to induce an apparent signal\nfor scaling in the cross-over region which we propose explains the scaling\nobserved for RP(2), RP(3) and SO(4)-matrix models. The signal for this `pseudo'\nscaling will occur for the RP(2) spin model in the cross-over region which is\nthe region in which computer simulations are done. We find that the RP(2) spin\nmodel is in the same universality class as the O(3) spin model but that it is\nlikely to require a very large correlation length before the true scaling of\nthis class sets in. We conjecture that the scaling flows are due either to the\ninfluence of a nearby new renormalized trajectory or to the ghost of the\nKosterlitz-Thouless trajectory in the associated XY model."
    },
    {
        "anchor": "Chiral Perturbation Theory on the Lattice and its Applications: Chiral perturbation theory (CPT), the low-energy effective theory of QCD, can\nbe used to describe QCD observables in the low-energy region in a\nmodel-independent way. At any given order in the chiral expansion, CPT\nintroduces a finite number of parameters that encode the short-distance physics\nand that must be determined from experiment or numerical lattice QCD\nsimulations. In this thesis, we calculate a number of hadronic observables in\nthe quenched and partially quenched versions of CPT:\n  Chiral corrections to B^(*) --> D^(*) at zero recoil are investigated in\nquenched CPT. We study in detail the charge radii of the meson and baryon\noctets, electromagnetic properties of the baryon decuplet, and the baryon\ndecuplet to octet electromagnetic transitions in both, quenched and partially\nquenched CPT. We further show how effects due to the finite size of the lattice\ncan be accounted for in heavy meson CPT and calculate, as explicit examples,\nneutral B meson mixing and the heavy-light meson decay constants. We also\ndemonstrate how one can account for effects due to finite lattice spacing in\nthe low-energy theories, considering as an example electromagnetic meson and\nbaryon properties.\n  The results of our calculations are crucial to extrapolate quenched and\npartially quenched lattice data from the heavier light quark masses used on the\nlattice to the physical values.",
        "positive": "Spontaneous creation of chromomagnetic field and A_0-condensate at high\n  temperature on a lattice: In a lattice formulation of SU(2)-gluodynamics, the spontaneous generation of\nchromomagnetic fields at high temperature is investigated. A procedure to\ndetermine this phenomenon is developed. By means of the $\\chi^2$-analysis of\nthe data set accumulating $5-10\\times 10^6$ Monte Carlo configurations, the\nspontaneous creation of the Abelian color magnetic field is indicated. The\ncommon generation of the magnetic field and $A_0$-condensate is also studied.\nIt is discovered that the field configuration consisting of the magnetized\nvacuum and the $A_0$-condensate is stable."
    },
    {
        "anchor": "Lattice QCD: Some topics from recent progresses in lattice QCD are reviewed.",
        "positive": "Nucleon form factors and couplings with $N_\\mathrm{f} = 2 + 1$ Wilson\n  fermions: We present updated results on the nucleon electromagnetic form factors and\naxial coupling calculated using CLS ensembles with $N_\\mathrm{f}=2+1$ dynamical\nflavours of Wilson fermions. The measurements are performed on large, fine\nlattices with a pseudoscalar mass reaching down to 200 MeV. The\ntruncated-solver method is employed to reduce the variance of the measurements.\nEstimation of the matrix elements is challenging due to large contamination\nfrom excited states and further investigation is necessary to bring these\neffects under control."
    },
    {
        "anchor": "The Deconfinement Transition in SO(3) Gauge Theory: The SO(3) lattice gauge theory with a Villain form of action was investigated\nby Monte Carlo techniques on asymmetric lattices with Nt = 2 and 4, where Nt is\nthe number of sites in the temporal extent. Unlike the results for higher Nt,\nonly one transition of second order was found for Nt = 2 . An extended action\nwith an irrelevant term to suppress Z_2 monopoles enabled us to get a better\nview of the deconfinement transition as the effects of bulk transition could be\nsuppressed as well. Although the action has no global Z_2 symmetry for the\nSO(3) theory, unlike the SU(2) theory at finite temperature, our study revealed\na second order deconfinement transition, with properties similar to the\ndeconfinement transition of SU(2).",
        "positive": "Dilaton EFT from p-regime to RMT in the $\u03b5$-regime: New results are reported from tests of a low-energy effective field theory\n(EFT) that includes a dilaton field to describe the emergent light scalar with\n${ 0^{++} }$ quantum numbers in the strongly coupled near-conformal gauge\ntheory with a massless fermion flavor doublet in the two-index symmetric\n(sextet) representation of the SU(3) color gauge group. In the parlor of\nwalking --- based on the observed light scalar, the small $\\beta$-function at\nstrong coupling, and the large anomalous scale dimension of the chiral\ncondensate --- the dilaton EFT hypothesis is introduced to test if it explains\nthe slowly changing nearly scale invariant physics that connects the\nasymptotically free UV fixed point and the far-infrared scale of chiral\nsymmetry breaking. The characteristic dilaton EFT signatures of scale symmetry\nbreaking are probed in this report in the small Compton wavelength limit of\nGoldstone bosons relative to the size of the lattice volume (p-regime) and in\nthe limit when the Goldstone wavelength exceeds the size of the volume\n($\\epsilon$-regime). Random matrix theory (RMT) analysis of the dilaton EFT is\napplied to the lowest part of the Dirac spectrum in the $\\epsilon$-regime to\ndirectly test predictions for the fundamental EFT parameters. The predictions,\nsensitive to the choice of the dilaton potential, were limited before to the\np-regime, using extrapolations from far above the chiral limit with untested\nuncertainties. The dilaton EFT analysis of the $\\epsilon$-regime was first\nsuggested in \\cite{Fodor:2019vmw}, with some results presented at this\nconference and with our continued post-conference analysis added to stimulate\ndiscussions."
    },
    {
        "anchor": "Lattice Nucleon Isovector Unpolarized Parton Distribution in the\n  Physical-Continuum Limit: We present the first lattice-QCD calculation of the nucleon isovector\nunpolarized parton distribution functions (PDFs) at the physical-continuum\nlimit using Large-Momentum Effective Theory (LaMET). The lattice results are\ncalculated using ensembles with multiple sea pion masses with the lightest one\naround 135~MeV, 3 lattice spacings $a\\in[0.06,0.12]$~fm, and multiple volumes\nwith $M_\\pi L$ ranging 3.3 to 5.5. We perform a simultaneous chiral-continuum\nextrapolation to obtain RI/MOM renormalized nucleon matrix elements with\nvarious Wilson-link displacements in the continuum limit at physical pion mass.\nThen, we apply one-loop perturbative matching to the quasi-PDFs to obtain the\nlightcone PDFs. We find the lattice-spacing dependence to be much larger than\nthe dependence on pion mass and lattice volume for these LaMET matrix elements.\nOur physical-continuum limit unpolarized isovector nucleon PDFs are found to be\nconsistent with global-PDF results.",
        "positive": "The Pressure in 2, 2+1 and 3 Flavour QCD: We calculate the pressure in QCD with two and three light quarks on a lattice\nof size 16^3x4 using tree level improved gauge and fermion actions. We argue\nthat for temperatures T > 2T_c systematic effects due to the finite lattice\ncut-off and non-vanishing quark masses are below 15% in this calculation and\ngive an estimate for the continuum extrapolated pressure in QCD with massless\nquarks. We find that the flavour dependence of the pressure is dominated by\nthat of the Stefan-Boltzmann constant. Furthermore we perform a calculation of\nthe pressure using 2 light (m_u,d/T=0.4) and one heavier quark (m_s/T = 1). In\nthis case the pressure is reduced relative to that of three flavour QCD. This\neffect is stronger than expected from the mass dependence of an ideal Fermi\ngas."
    },
    {
        "anchor": "Perturbative Renormalization Factors of Baryon Number Violating\n  Operators for Improved Quark and Gauge Actions in Lattice QCD: We calculate one-loop renormalization factors of three-quark operators, which\nappear in the low energy effective Lagrangian of the nucleon decay, for\n$O(a)$-improved quark action and gauge action including six-link loops. This\ncalculation is required to predict the hadronic nucleon decay matrix elements\nin the continuum regularization scheme using lattice QCD. We present detailed\nnumerical results of the one-loop coefficients for general values of the clover\ncoefficients employing the several improved gauge actions in the Symanzik\napproach and in the Wilson's renormalization group approach. The magnitudes of\nthe one-loop coefficients for the improved gauge actions show sizable reduction\ncompared to those for the plaquette action.",
        "positive": "Universality in short-time critical gluodynamics with heat-bath-inspired\n  algorithms: Short-time dynamics technique is used to study the relaxation process for the\n(2+1)-dimensional critical gluodynamics of the SU(2) lattice gauge theory. A\ngeneralized class of heat-bath-inspired updating algorithms was employed during\nthe short-time regime of the dynamic evolution for performance comparison. The\nstatic and dynamic critical exponents of the theory were measured, serving as a\ndynamic benchmark for algorithmic efficiency. Our results are in agreement with\npredictions from universality hypothesis and suggest that there is an\nunderlying universal dynamics shared by the analyzed algorithms."
    },
    {
        "anchor": "Roma versus Zaragoza: The Roma and Zaragoza actions for chiral fermions on the lattice are shown to\nbe essentially equivalent. The auxiliary fermion fields in the Roma model can\nbe integrated out, and the resulting action is a special case of the Zaragoza\napproach. We use this result to perform a mean-field study of the phase diagram\nof chiral Yukawa models in the Roma formulation.",
        "positive": "Critical Momenta of Lattice Chiral Fermions: We determine the critical momenta for chiral fermions in the domain wall\nmodel recently suggested by Kaplan. For a wide range of domain wall masses $m$\nand Wilson couplings $r$ we explicitly exhibit the regions in momentum space\nwhere the fermions are chiral. We compare the critical momenta for the\ninfinitely large system with those obtained on a finite lattice."
    },
    {
        "anchor": "B_s mesons from the lattice: Excited states: The energies of different angular momentum states of a heavy-light meson were\nmeasured on a lattice in PRD 58, 34506 (1998) . We have now continued this\nstudy using several different lattices, quenched and unquenched, that have\ndifferent physical lattice sizes, clover coefficients, hopping parameters and\nquark-gluon couplings. The heavy quark is taken to be infinitely heavy, whereas\nthe light quark mass is approximately that of the strange quark. By\ninterpolating in the heavy and light quark masses we can thus compare the\nlattice results with the B_s meson. Most interesting is the lowest P-wave B_s\nstate, since it is possible that it lies below the BK threshold and hence is\nvery narrow. Unfortunately, there are no experimental results on P-wave B_s\nmesons available at present.\n  In addition to the energy spectrum, we measured earlier also vector (charge)\nand scalar (matter) radial distributions of the light quark in the S-wave\nstates of a heavy-light meson on a lattice (PRD 65, 014512 (2002) and Eur.\nPhys. J. C 28, 79 (2003)). Now we are extending the study of radial\ndistributions to P-wave states.",
        "positive": "Delta electromagnetic form factors and quark transverse charge densities\n  from lattice QCD: We discuss the techniques to extract the electromagnetic Delta form factors\nin Lattice QCD. We evaluate these form factors using dynamical fermions with\nsmallest pion mass of about 350 MeV. We pay particular attention to the\nextraction of the electric quadrupole form factor that signals a deformation of\nthe Delta. The magnetic moment of the $\\Delta$ is extrapolated using a chiral\neffective field theory. Using the form factors we evaluate the transverse\ndensity distributions in the infinite momentum frame showing deformation in the\nDelta."
    },
    {
        "anchor": "Baryon Axial Charges and Momentum Fractions with N_f=2+1 Dynamical\n  Fermions: We report on recent results of the QCDSF/UKQCD Collaboration on\ninvestigations of baryon structure using configurations generated with N_f=2+1\ndynamical flavours of O(a) improved Wilson fermions. With the strange quark\nmass as an additional dynamical degree of freedom in our simulations we avoid\nthe need for a partially quenched approximation when investigating the\nproperties of particles containing a strange quark, e.g. the hyperons. In\nparticular, we will focus on the nucleon and hyperon axial charges and quark\nmomentum fractions.",
        "positive": "Decay constants of P-wave heavy-light mesons from unquenched lattice QCD: We review some decays that require knowledge of the decay constants of\n$0^{+}$ heavy-light mesons. We compute the decay constants of P-wave\nheavy-light mesons from unquenched lattice QCD, with two degenerate flavours of\nsea quarks, at a single lattice spacing. The lightest sea quark mass used in\nthe calculation is a third of the strange quark mass. For the charm-strange\nmeson we obtain the decay constant: $f_{D_{s 0^+}} = 340(110)$ MeV using our\nnormalisation conventions. We obtain the $f_{P_s}^{static}$ (static-strange\nP-wave) decay constant as $302(39)$ MeV."
    },
    {
        "anchor": "Light-Meson Two-Photon Decays in Full QCD: We present a study of two-photon decays of light mesons, focusing on the\nneutral pion decay. This important process highlights the effects of the axial\nanomaly in QCD but has been little studied on the lattice. By applying the\nLehmann-Symanzik-Zimmermann (LSZ) reduction formula, we reconstruct the\nelectromagnetic matrix elements from three-point vector-vector Green functions\ncalculated on 2+1-flavor isotropic clover lattices.",
        "positive": "Tantalizing dilaton tests from a near-conformal EFT: The dilaton low-energy effective field theory (EFT) of an emergent light\nscalar is probed in the paradigm of strongly coupled near-conformal gauge\ntheories. These studies are motivated by models which exhibit small\n$\\beta$-functions near the conformal window (CW), perhaps with slow\nscale-dependent walking and a light scalar with ${ 0^{++} }$ quantum numbers.\nWe report our results from the hypothesis of a dilaton inspired EFT analysis\nwith two massless fermions in the two-index symmetric (sextet) representation\nof the SU(3) color gauge group. With important caveats in our conclusions,\nconformal symmetry breaking entangled with chiral symmetry breaking would drive\nthe near-conformal infrared behavior of the theory predicting characteristic\ndilaton signatures of the light scalar from broken scale invariance when probed\non relevant scales of fermion mass deformations. From a recently reasoned\nchoice of the dilaton potential in the EFT description~\\cite{Golterman:2016lsd}\nwe find an unexpectedly light dilaton mass in the chiral limit at $m_d/f_\\pi =\n1.56(28)$, set in units of the pion decay constant $f_\\pi$. Subject to further\nstatistical and systematic tests of continued post-conference analysis, this\nresult is significantly lower than our earlier estimates from less controlled\nextrapolations of the light scalar (the $\\sigma$-particle) to the massless\nfermion limit of chiral perturbation theory. We also discuss important\ndistinctions between the dilaton EFT analysis and the linear $\\sigma$-model\nwithout dilaton signatures. For comparative reasons, we comment on dilaton\ntests from recent work with fermions in the fundamental representation with\n$n_f=8$ flavors."
    },
    {
        "anchor": "Homotopy data as part of the lattice field: A first study: Fields exhibit a variety of topological properties, like different\ntopological charges, when field space in the continuum is composed by more than\none topological sector. Lattice treatments usually encounter difficulties\ndescribing those properties. In this work, we show that by augmenting the usual\nlattice fields to include extra variables describing local topological\ninformation (more precisely, regarding homotopy), the topology of the space of\nfields in the continuum is faithfully reproduced in the lattice. We apply this\nextended lattice formulation to some simple models with non-trivial topological\ncharges, and we study their properties both analytically and via Monte Carlo\nsimulations.",
        "positive": "Antiheavy-Antiheavy-Light-Light Four-Quark Bound States: We present our recent results on antiheavy-antiheavy-light-light tetraquark\nsystems using lattice QCD. Our study of the $ \\bar{b}\\bar{b}us $ four-quark\nsystem with quantum numbers $ J^P=1^+ $ and the $ \\bar{b}\\bar{c}ud $ four-quark\nsystems with $ I(J^P)=0(0^+) $ and $ I(J^P)=0(1^+) $ utilizes scattering\noperators at the sink to improve the extraction of the low-lying energy levels.\nWe found a bound state for $ \\bar{b}\\bar{b}us $ with $\nE_{\\textrm{bind},\\bar{b}\\bar{b}us} = (-86 \\pm 22 \\pm 10)\\,\\textrm{MeV} $, but\nno indication for a bound state in both $ \\bar{b}\\bar{c}ud $ channels.\nMoreover, we show preliminary results for $ \\bar{b}\\bar{b}ud $ with $\nI(J^P)=0(1^+) $, where we used scattering operators both at the sink and the\nsource. We found a bound state and determined its infinite-volume binding\nenergy with a scattering analysis, resulting in $\nE_{\\textrm{bind},\\bar{b}\\bar{b}ud} =(-103 \\pm 8 )\\,\\textrm{MeV} $."
    },
    {
        "anchor": "The Dyson-Schwinger equation of a link variable in lattice Landau gauge\n  theory: We derive the Dyson-Schwinger equation of a link variable in SU(n) lattice\ngauge theory in minimal Landau gauge and confront it with Monte-Carlo data for\nthe different terms. Preliminary results for the lattice analog of the\nKugo-Ojima confinement criterion is also shown.",
        "positive": "Determining hybrid content of heavy quarkonia using lattice\n  nonrelativistic QCD: Using lowest-order lattice NRQCD to create heavy meson propagators and\napplying the spin-dependent interaction, $c_B^{}\n\\frac{-g}{2m_q}\\vec\\sigma\\cdot\\vec{B}$, at varying intermediate time slices, we\ncompute the off-diagonal matrix element of the Hamiltonian for the\nquarkonium-hybrid two-state system. Diagonalizing this two-state Hamiltonian,\nthe admixture of hybrid ($|Q\\bar{Q}g>$) in the ground state is found. We\npresent results from a set of quenched lattices with an interpolation in quark\nmass to match the bottomonium spectrum."
    },
    {
        "anchor": "Magnetic and chiral universality classes in a 3D Yukawa model: The 3D Yukawa model with U(1) chiral symmetry is investigated in a broad\ninterval of parameters using the Binder method. Critical exponents of the\nWilson-Fisher (magnetic) and Gross-Neveu (chiral) universality classes are\nmeasured. The model is dominated by the chiral universality class. However at\nweak coupling we observe a crossover between both classes, manifested by\ndifficulties with the Binder method which otherwise works well.",
        "positive": "Elastic $\u03c0-N$ scattering in the $I=3/2$ channel: We present our study of $\\pi-N$ scattering in the iso-spin $I=3/2$ channel\nfor the first time at the physical point. The calculation is performed using\n$N_f=2+1+1$ flavors of twisted mass fermions with clover improvement at\nphysical pion mass. We compute energy levels for the rest frame and moving\nframes up to a total momentum of $|\\vec{P}|=\\sqrt{3} \\,\\frac{2\\pi}{L}$, and for\nall the relevant ireducible representations of the lattice symmetry groups. We\nperform a phase-shift analysis including $s\\,(\\ell=0)$ and $p\\,(\\ell=1)$ wave\nphase shifts assuming a Breit-Wigner form and determine the parameters of the\n$\\Delta$ resonance."
    },
    {
        "anchor": "Determination of the running coupling in pure SU(4) Yang-Mills theory: The Schrodinger functional is used to define a renormalised coupling for pure\nSU(4) Yang-Mills theory, with Wilson action and suitably selected boundary\nconditions on the link field. The coupling, which runs with the size of the\nlattice, is then determined by a finite-size scaling technique through a large\nrange of momenta, thereby allowing a connection to be made between the high\nenergy regime and the low energy non-perturbative regime, where contact is made\nwith the physical scale of the theory. Using data from previous SU(2) and SU(3)\nsimulations obtained with the same technique, the running of the 't Hooft\ncoupling defined through the Schrodinger functional is studied, and we check\nwhether the large-N expectation that g^2*N is a universal function of the\nenergy scale E holds down to energies of the order of the string tension.\nFinally, we determine Lambda_SF in units of the string tension as a function of\nN at leading order in 1/N^2.",
        "positive": "SU(3) breaking and the pseudo-scalar spectrum in multi-taste QCD: Using the Sigma model to explore the lowest order pseudo-scalar spectrum with\nSU(3) breaking, this talk considers an additional exact \"taste\" symmetry to\nmimic species doubling. Rooting replicas of a valid approach such as Wilson\nfermions reproduces the desired physical spectrum. In contrast, extra\nsymmetries of the rooted staggered approach leave spurious states and a flavor\ndependent taste multiplicity."
    },
    {
        "anchor": "Doubly Heavy Baryons and Quark-Diquark Symmetry in Quenched and\n  Partially Quenched Chiral Perturbation Theory: We extend the chiral Lagrangian with heavy quark-diquark symmetry to quenched\nand partially quenched theories. These theories are used to derive formulae for\nthe chiral extrapolation of masses and hyperfine splittings of doubly heavy\nbaryons in lattice QCD simulations. A quark-diquark symmetry prediction for the\nhyperfine splittings of heavy mesons and doubly heavy baryons is rather\ninsensitive to chiral corrections in both quenched and partially quenched QCD.\nExtrapolation formulae for the doubly heavy baryon electromagnetic transition\nmoments are also determined for the partially quenched theory.",
        "positive": "Improving lattice perturbation theory: Lepage and Mackenzie have shown that tadpole renormalization and systematic\nimprovement of lattice perturbation theory can lead to much improved numerical\nresults in lattice gauge theory. It is shown that lattice perturbation theory\nusing the Cayley parametrization of unitary matrices gives a simple analytical\napproach to tadpole renormalization, and that the Cayley parametrization gives\nlattice gauge potentials gauge transformations close to the continuum form. For\nexample, at the lowest order in perturbation theory, for SU(3) lattice gauge\ntheory, at $\\beta=6,$ the `tadpole renormalized' coupling $\\tilde g^2 = {4\\over\n3} g^2,$ to be compared to the non-perturbative numerical value $\\tilde g^2 =\n1.7 g^2.$"
    },
    {
        "anchor": "A test on analytic continuation of thermal imaginary-time data: Some time ago, Cuniberti et al have proposed a novel method for analytically\ncontinuing thermal imaginary-time correlators to real time, which requires no\nmodel input and should be applicable with finite-precision data as well. Given\nthat these assertions go against common wisdom, we report on a naive test of\nthe method with an idealized example. We do encounter two problems, which we\nspell out in detail; this implies that systematic errors are difficult to\nquantify. On a more positive note, the method is simple to implement and allows\nfor an empirical recipe by which a reasonable qualitative estimate for some\ntransport coefficient may be obtained, if statistical errors of an\nultraviolet-subtracted imaginary-time measurement can be reduced to roughly\nbelow the per mille level.",
        "positive": "Perturbative Matching of Heavy-Light Currents with NRQCD Heavy Quarks: We present further results for one-loop matching of heavy-light axial and\nvector currents between continuum QCD and a lattice theory with NRQCD heavy\nquarks and massless clover quarks."
    },
    {
        "anchor": "Incorporating Chiral Symmetry and Heavy Quark Theory in Extrapolations\n  of Octet Baryon Charge Radii: We extrapolate lattice calculations of electric charge radii of the spin-1/2\nbaryon octet to the physical regime. The extrapolation procedure incorporates\nchiral perturbation theory and heavy quark effective theory in the appropriate\nlimits. In particular, this procedure includes the non-analytic, logarithmic\nterms from pion loops. The electric charge radii of the nucleons and $\\Sigma^-$\nobtained from the chiral extrapolations agree well with experimental data. We\nmake predictions for the charge radii of the remaining baryons in anticipation\nof future experimental measurements.",
        "positive": "Fourier Accelerated Conjugate Gradient Lattice Gauge Fixing: We provide details of the first implementation of a non-linear conjugate\ngradient method for Landau and Coulomb gauge fixing with Fourier acceleration.\nWe find clear improvement over the Fourier accelerated steepest descent method,\nwith the average time taken for the algorithm to converge to a fixed, high\naccuracy, being reduced by a factor of 2 to 4."
    },
    {
        "anchor": "The bottomonium spectrum at finite temperature from $N_f=2+1$ lattice\n  QCD: We present results on the bottomonium spectrum at temperatures above and\nbelow the deconfinement crossover temperature, $T_c$, from dynamical lattice\nQCD simulations. The heavy quark is treated with a non-relativistic effective\nfield theory on the lattice and serves as a probe of the hot medium. Ensembles\nwith a finer spatial lattice spacing and a greater range of temperatures below\n$T_c$ than those previously employed by this collaboration are used. In\naddition, there are $N_f=2+1$ flavours of Wilson clover quark in the sea with\n$M_\\pi\\approx400$ MeV and we perform a more careful tuning of the bottom quark\nmass in this work. We calculate the spectral functions of S and P wave\nbottomonium states using the maximum entropy method and confirm earlier\nfindings on the survival of the ground state S wave states up to at least\n$2T_c$ and the immediate dissociation of the P wave states above $T_c$.",
        "positive": "Non-perturbative Renormalization of Bilinear Operators with Improved\n  Staggered Quarks: We present renormalization factors for the bilinear operators obtained using\nthe non-perturbative renormalization method (NPR) in the RI-MOM scheme with\nimproved staggered fermions on the MILC asqtad lattices ($N_f = 2+1$). We use\nthe MILC coarse ensembles with $20^3 \\times 64$ geometry and $am_{\\ell}/am_s =\n0.01/0.05$. We obtain the wave function renormalization factor $Z_q$ from the\nconserved vector current and the mass renormalization factor $Z_m$ from the\nscalar bilinear operator. We also present preliminary results of\nrenormalization factors for other bilinear operators."
    },
    {
        "anchor": "Helicity operators for mesons in flight on the lattice: Motivated by the desire to construct meson-meson operators of definite\nrelative momentum in order to study resonances in lattice QCD, we present a set\nof single-meson interpolating fields at non-zero momentum that respect the\nreduced symmetry of a cubic lattice in a finite cubic volume. These operators\nfollow from the subduction of operators of definite helicity into irreducible\nrepresentations of the appropriate little groups. We show their effectiveness\nin explicit computations where we find that the spectrum of states interpolated\nby these operators is close to diagonal in helicity, admitting a description in\nterms of single-meson states of identified J^{PC}. The variationally determined\noptimal superpositions of the operators for each state give rapid relaxation in\nEuclidean time to that state, ideal for the construction of meson-meson\noperators and for the evaluation of matrix elements at finite momentum.",
        "positive": "Global Symmetries of Naive and Staggered Fermions in Arbitrary\n  Dimensions: It is well-known that staggered fermions do not necessarily satisfy the same\nglobal symmetries as the continuum theory. We analyze the mechanism behind this\nphenomenon for arbitrary dimension and gauge group representation. For this\npurpose we vary the number of lattice sites between even and odd parity in each\nsingle direction. Since the global symmetries are manifest in the lowest\neigenvalues of the Dirac operator, the spectral statistics and also the\nsymmetry breaking pattern will be affected. We analyze these effects and\ncompare our predictions with Monte-Carlo simulations of naive Dirac operators\nin the strong coupling limit."
    },
    {
        "anchor": "The lattice Landau gauge gluon propagator: lattice spacing and volume\n  dependence: The interplay between the finite volume and finite lattice spacing is\ninvestigated using lattice QCD simulations to compute the Landau gauge gluon\npropagator. Comparing several ensembles with different lattice spacings and\nphysical volumes, we conclude that the dominant effects, in the infrared\nregion, are associated with the use of a finite lattice spacing. The\nsimulations show that decreasing the lattice spacing, while keeping the same\nphysical volume, leads to an enhancement of the infrared gluon propagator. In\nthis sense, the data from $\\beta=5.7$ simulations, which uses an $a \\approx\n0.18$ fm, provides a lower bound for the infinite volume propagator.",
        "positive": "The complex Langevin analysis of spontaneous symmetry breaking induced\n  by complex fermion determinant: In many interesting physical systems, the determinant which appears from\nintegrating out fermions becomes complex, and its phase plays a crucial role in\nthe determination of the vacuum. An example of this is QCD at low temperature\nand high density, where various exotic fermion condensates are conjectured to\nform. Another example is the Euclidean version of the type IIB matrix model for\n10d superstring theory, where spontaneous breaking of the SO(10) rotational\nsymmetry down to SO(4) is expected to occur. When one applies the complex\nLangevin method to these systems, one encounters the singular-drift problem\nassociated with the appearance of nearly zero eigenvalues of the Dirac\noperator. Here we propose to avoid this problem by deforming the action with a\nfermion bilinear term. The results for the original system are obtained by\nextrapolations with respect to the deformation parameter. We demonstrate the\npower of this approach by applying it to a simple matrix model, in which\nspontaneous symmetry breaking from SO(4) to SO(2) is expected to occur due to\nthe phase of the complex fermion determinant. Unlike previous work based on a\nreweighting-type method, we are able to determine the true vacuum by\ncalculating the order parameters, which agree with the prediction by the\nGaussian expansion method."
    },
    {
        "anchor": "Hadronic-vacuum-polarization contribution to the muon's anomalous\n  magnetic moment from four-flavor lattice QCD: We calculate the contribution to the muon anomalous magnetic moment hadronic\nvacuum polarization from {the} connected diagrams of up and down quarks,\nomitting electromagnetism. We employ QCD gauge-field configurations with\ndynamical $u$, $d$, $s$, and $c$ quarks and the physical pion mass, and analyze\nfive ensembles with lattice spacings ranging from $a \\approx 0.06$ to~0.15~fm.\nThe up- and down-quark masses in our simulations have equal masses $m_l$. We\nobtain, in this world where all pions have the mass of the $\\pi^0$, $10^{10}\na_\\mu^{ll}({\\rm conn.}) = 637.8\\,(8.8)$, in agreement with independent\nlattice-QCD calculations. We then combine this value with published lattice-QCD\nresults for the connected contributions from strange, charm, and bottom quarks,\nand an estimate of the uncertainty due to the fact that our calculation does\nnot include strong-isospin breaking, electromagnetism, or contributions from\nquark-disconnected diagrams. Our final result for the total\n$\\mathcal{O}(\\alpha^2)$ hadronic vacuum polarization to the muon's anomalous\nmagnetic moment is~$10^{10}a_\\mu^{\\rm HVP,LO} = 699(15)_{u,d}(1)_{s,c,b}$,\nwhere the errors are from the light-quark and heavy-quark contributions,\nrespectively. Our result agrees with both {\\it ab-initio} lattice-QCD\ncalculations and phenomenological determinations from experimental\n$e^+e^-$-scattering data. It is $1.3\\sigma$ below the \"no new physics\" value of\nthe hadronic-vacuum-polarization contribution inferred from combining the BNL\nE821 measurement of $a_\\mu$ with theoretical calculations of the other\ncontributions.",
        "positive": "Elastic anomaly of heavy fermion systems in a crystalline field: An elastic anomaly, observed in the heavy fermi liquid state of Ce alloys\n(for example, CeCu$_6$ and CeTe), is analyzed by using the infinite-$U$\nAnderson lattice model. The four atomic energy levels are assumed for\nf-electrons. Two of them are mutually degenerate. A small crystalline splitting\n$2\\Delta$ is assumed between two energy levels. The fourfold degenerate\nconduction bands are also considered in the model. We solve the model using the\nmean field approximation to slave bosons, changing the Fermi energy in order to\nkeep the total electron number constant. The nonzero value of the mean field of\nthe slave bosons persists over the temperatures much higher than the Kondo\ntemperature. This is the effect of the constant electron number. Next, the\nlinear susceptibility with respect to $\\Delta$ is calculated in order to obtain\nthe renomalized elastic constant. The resulting temperature dependence of the\nconstant shows the downward dip. We point out the relation of our finding with\nthe experimental data."
    },
    {
        "anchor": "Quarkonium Physics and $\u03b1_{strong}$ from Quarkonia: Recent results in Quarkonia are reviewed, including updates on spectroscopy\nand $\\alpha_s$, and a first look at quarkonium annihilation decays.",
        "positive": "On the Structure of the Lambda 1405: For almost 50 years the structure of the Lambda 1405 resonance has been a\nmystery. Recently, a new lattice QCD simulation showing that its strange\nmagnetic form factor vanishes, together with a comprehensive Hamiltonian\nanalysis of the lattice QCD energy levels, has unambiguously established that\nthe structure is dominated by a bound anti-kaon--nucleon component [1]. Here we\npresent supplementary information for Ref. [1] including a presentation of the\nrelevant Hamiltonian effective field theory and an illustration of the volume\ndependence of the results and their connection to the infinite volume limit of\nNature."
    },
    {
        "anchor": "Proton decay matrix elements on the lattice at physical pion mass: Proton decay is a major prediction of Grand-Unified Theories (GUT) and its\nobservation would indicate baryon number violation that is required for\nbaryogenesis. Many decades of searching for proton decay have constrained its\nrate and ruled out some of the simplest GUT models. Apart from the baryon\nnumber-violating interactions, this rate also depends on transition amplitudes\nbetween the proton and mesons or leptons produced in the decay, which are\nmatrix elements of three-quark operators. We report nonperturbative calculation\nof these matrix elements for the most studied two-body decay channels into a\nmeson and antilepton done on a lattice with physical light and strange quark\nmasses and lattice spacings $a\\approx0.14$ and 0.20 fm. We perform\nnonperturbative renormalization and excited state analysis to control\nassociated systematic effects. Our results largely agree with previous lattice\ncalculations done with heavier quark masses and thus remove ambiguity in ruling\nout some simple GUT theories due to quark mass dependence of hadron structure.",
        "positive": "Generalized Parton Distributions in Full Lattice QCD: We present recent results on generalized parton distributions from dynamical\nlattice QCD calculations. Our set of twelve different combinations of couplings\nand quark masses allows for a preliminary study of the pion mass dependence of\nthe transverse nucleon structure."
    },
    {
        "anchor": "Chiral phase structure of three flavor QCD in a background magnetic\n  field: We investigate the chiral phase structure of three flavor QCD in a background\n$U(1)$ magnetic field using the standard staggered action and the Wilson\nplaquette gauge action. We perform simulations on lattices with a temporal\nextent of $N_\\tau=4$ and four spatial extents of $N_\\sigma = 8,16, 20$ and 24.\nWe choose a smaller-than-physical quark mass in lattice spacing as $am = 0.030$\nsuch that there exists a crossover transition at vanishing magnetic fields, and\nadopt two values of magnetic field strength in lattice spacing $a \\sqrt{\ne{B}}\\simeq 1.5$ and 2. We find that the transition becomes stronger in the\npresence of a background magnetic field, and turns into a first order as seen\nfrom the volume scaling of the order parameter susceptibility as well as the\nmetastable states in the time history of the chiral condensate. On the other\nhand, the chiral condensate and transition temperature always increase with $B$\neven within the regime of a first order phase transition. This suggests that\nthe discrepancy in the behavior of chiral condensates and transition\ntemperature as a function of $B$ between earlier lattice studies using\nlarger-than-physical pion masses with standard staggered fermions and those\nusing physical pions with improved staggered fermions is mainly due to lattice\ncutoff effects.",
        "positive": "Hadronic Interactions: Understanding hadronic interactions is crucial for investigating the\nproperties of unstable hadrons, since measuring physical quantities for\nunstable hadrons including the resonance mass and decay width requires\nsimultaneous calculations of final scattering states. Recent studies of\nhadronic scatterings and decays are reviewed from this point of view.\n  The nuceon-nucleon and multi-nucleon interactions are very important to\nunderstand the formation of nucleus from the first principle of QCD. These\ninteractions have been studied mainly by two methods, due originally to\nL\\\"uscher and to HALQCD. The results obtained from the two methods are compared\nin three channels, $I=2$ two-pion, H-dibaryon, and two-nucleon channels. So far\nthe results from the two methods for the two-nucleon channels are different\neven at the level of the presence or absence of bound states. We then discuss\npossible uncertainties in each method.\n  Recent results on the binding energy for helium nuclei are also reviewed."
    },
    {
        "anchor": "Glueball properties in anisotropic SU(3) lattice QCD with improved\n  action: We study the glueballs properties at finite temperature using SU(3) lattice\nQCD at the quenched level with the anisotropic lattice. We use the tree-level\nSymanzik O(a^2) improved action. We present our preliminary results which shows\nthe slight reduction of the scalar glueball mass near T_c",
        "positive": "Locality of staggered overlap operators: We give an explicit proof for the locality of staggered overlap operators.\nThe proof covers the original two flavor construction by Adams as well as a\nsingle flavor version. As in the case of Neuberger's operator, an admissibility\ncondition for the gauge fields is required."
    },
    {
        "anchor": "Precise determination of $B_K$ and light quark masses in quenched\n  domain-wall QCD: We calculate non-perturbative renormalization factors at hadronic scale for\n$\\Delta S=2$ four-quark operators in quenched domain-wall QCD using the\nSchr\\\"{o}dinger functional method. Combining them with the non-perturbative\nrenormalization group running by the Alpha collaboration, our result yields the\nfully non-perturbative renormalization factor, which converts the lattice bare\n$B_K$ to the renormalization group invariant (RGI) $\\hat{B}_K$. Applying this\nto the bare $B_K$ previously obtained by the CP-PACS collaboration at\n$a^{-1}\\simeq 2, 3, 4$ GeV, we obtain $\\hat{B}_K=0.782(5)(7)$ (equivalent to\n$B_K^{\\bar{\\rm MS}}({\\rm NDR}, 2 {\\rm GeV}) = 0.565(4)(5)$ by 2-loop running)\nin the continuum limit, where the first error is statistical and the second is\nsystematic due to the continuum extrapolation. Except the quenching error, the\ntotal error we have achieved is less than 2%, which is much smaller than the\nprevious ones. Taking the same procedure, we obtain $m_{u,d}^{\\rm\nRGI}=5.613(66)$ MeV and $m_s^{\\rm RGI}=147.1(17)$ MeV (equivalent to\n$m_{u,d}^{\\bar{\\rm MS}}(2 {\\rm GeV})=4.026(48)$ MeV and $m_{s}^{\\bar{\\rm MS}}(2\n{\\rm GeV})=105.6(12)$ MeV by 4-loop running) in the continuum limit.",
        "positive": "The scalar glueball from a tadpole-improved action: The scalar glueball mass and the string tension are computed in lattice SU(3)\ngauge theory with the aim of establishing the effectiveness of the improved\naction approach in removing finite-spacing artifacts."
    },
    {
        "anchor": "A variational method for spectral functions: The Generalized Eigenvalue Problem (GEVP) has been used extensively in the\npast in order to reliably extract energy levels from time-dependent Euclidean\ncorrelators calculated in Lattice QCD. We propose a formulation of the GEVP in\nfrequency space. Our approach consists of applying the model-independent\nBackus-Gilbert method to a set of Euclidean two-point functions with common\nquantum numbers. A GEVP analysis in frequency space is then applied to a matrix\nof estimators that allows us, among other things, to obtain particular linear\ncombinations of the initial set of operators that optimally overlap to\ndifferent local regions in frequency. We apply this method to lattice data from\nNRQCD. This approach can be interesting both for vacuum physics as well as for\nfinite-temperature problems.",
        "positive": "Domain wall fermion zero modes on classical topological backgrounds: The domain wall approach to lattice fermions employs an additional dimension,\nin which gauge fields are merely replicated, to separate the chiral components\nof a Dirac fermion. It is known that in the limit of infinite separation in\nthis new dimension, domain wall fermions have exact zero modes, even for gauge\nfields which are not smooth. We explore the effects of finite extent in the\nfifth dimension on the zero modes for both smooth and non-smooth topological\nconfigurations and find that a fifth dimension of around ten sites is\nsufficient to clearly show zero mode effects. This small value for the extent\nof the fifth dimension indicates the practical utility of this technique for\nnumerical simulations of QCD."
    },
    {
        "anchor": "Understanding the problem with logarithmic singularities in the complex\n  Langevin method: In recent years, there has been remarkable progress in theoretical\njustification of the complex Langevin method, which is a promising method for\nevading the sign problem in the path integral with a complex weight. There\nstill remains, however, an issue concerning occasional failure of this method\nin the case where the action involves logarithmic singularities such as the one\nappearing from the fermion determinant in finite density QCD. In this talk, we\npoint out that this failure is due to the breakdown of the relation between the\ncomplex weight which satisfies the Fokker-Planck equation and the probability\ndistribution generated by the stochastic process. In fact, this kind of failure\ncan occur in general when the stochastic process involves a singular drift\nterm. We show, however, in simple examples, that there exists a parameter\nregion in which the method works although the standard reweighting method is\nhardly applicable.",
        "positive": "On the phase structure of five-dimensional SU(2) gauge theories with\n  anisotropic couplings: The phase diagram of five-dimensional SU(2) gauge theories is explored using\nMonte Carlo simulations of the theory discretized on a Euclidean lattice using\nthe Wilson plaquette action and periodic boundary conditions. We simulate\nanisotropic gauge couplings which correspond to different lattice spacings a_4\nin the four dimensions and a_5 along the extra dimension. In particular we\nstudy the case where a_5>a_4. We identify a line of first order phase\ntransitions which separate the confined from the deconfined phase. We perform\nsimulations in large volume at the bulk phase transition staying in the\nconfined vacuum. The static potential measured in the hyperplanes orthogonal to\nthe extra dimension hint at dimensional reduction. We also locate and analyze\nsecond order phase transitions related to breaking of the center along one\ndirection."
    },
    {
        "anchor": "B -> D* l nu and B -> D l nu form factors in staggered chiral\n  perturbation theory: We calculate the B -> D and B -> D* form factors at zero recoil in Staggered\nChiral Perturbation Theory. We consider heavy-light mesons in which only the\nlight (u, d, or s) quark is staggered; current lattice simulations generally\nuse a highly improved action such as the Fermilab or NRQCD action for the heavy\n(b or c) quark. We work to lowest nontrivial order in the heavy quark expansion\nand to one-loop in the chiral expansion. We present results for a partially\nquenched theory with three sea quarks in which there are no mass degeneracies\n(the \"1+1+1\" theory) and for a partially quenched theory in which the u and d\nsea quark masses are equal (the \"2+1\" theory). We also present results for full\n(2+1) QCD, along with a numerical estimate of the size of staggered\ndiscretization errors. Finally, we calculate the finite volume corrections to\nthe form factors and estimate their numerical size in current lattice\nsimulations.",
        "positive": "Dual vortices and gauge choice in Abelian projected SU(2) lattice gauge\n  theory: We explore vortex formation for Abelian projected SU(2) in the Polyakov gauge\nand compare the results with those calculated in the maximal Abelian gauge. In\nboth gauges, a non-zero vacuum expectation value of a monopole field operator\nsignals confinement. We find vortices in the Polyakov projection, confirming\nthe connection between the dual superconductor order parameter and the\nexistence of vortices. However we find that the Polyakov Abelian projection is\nproblematic, leaving the maximal Abelian projection as the best candidate to\ndefine an effective theory of confinement in this scenario."
    },
    {
        "anchor": "From square plaquettes to triamond lattices for SU(2) gauge theory: Lattice gauge theory should be able to address significant new scientific\nquestions when implemented on quantum computers. In practice, error-mitigation\ntechniques have already allowed encouraging progress on small lattices. In this\nwork we focus on a truncated version of SU(2) gauge theory, which is a familiar\nnon-Abelian step toward quantum chromodynamics. First, we demonstrate effective\nerror mitigation for imaginary time evolution on a lattice having two square\nplaquettes, obtaining the ground state using an IBM quantum computer and\nobserving that this would have been impossible without error mitigation. Then\nwe propose the triamond lattice as an expedient approach to lattice gauge\ntheories in three spatial dimensions, deriving the Hamiltonian and obtaining\nenergy eigenvalues and eigenstates from a noiseless simulator for a\nthree-dimensional unit cell.",
        "positive": "The strange and light quark contributions to the nucleon mass from\n  Lattice QCD: We determine the strangeness and light quark fractions of the nucleon mass by\ncomputing the quark line connected and disconnected contributions to the matrix\nelements m_q <N|qbar q|N> in lattice QCD, using the non-perturbatively improved\nSheikholeslami-Wohlert Wilson Fermionic action. We simulate n_F=2 mass\ndegenerate sea quarks with a pion mass of about 285 MeV and a lattice spacing a\napprox 0.073 fm. The renormalization of the matrix elements involves mixing\nbetween contributions from different quark flavours. The pion-nucleon\nsigma-term is extrapolated to physical quark masses exploiting the sea quark\nmass dependence of the nucleon mass. We obtain the renormalized values\n\\sigma_{\\pi N} = 38(12) MeV at the physical point and f_{T_s}=\\sigma_s/m_N=\n0.012(14)^{+10}_{-3} for the strangeness contribution at our larger than\nphysical sea quark mass."
    },
    {
        "anchor": "Hadronic light-by-light contribution to the muon anomaly from lattice\n  QCD with infinite volume QED at physical pion mass: The hadronic light-by-light scattering contribution to the muon anomalous\nmagnetic moment, $(g-2$)/2, is computed in the infinite volume QED framework\nwith lattice QCD. We report $a_\\mu^\\text{HLbL}=12.47(1.15)(0.99) \\times\n10^{-10}$ where the first error is statistical and the second systematic. The\nresult is mainly based on the 2+1 flavor M\\\"obius domain wall fermion ensemble\nwith inverse lattice spacing $a^{-1} = 1.73~\\mathrm{GeV}$, lattice size\n$L=5.5~\\mathrm{fm}$, and $m_\\pi = 139~\\mathrm{MeV}$, generated by the RBC-UKQCD\ncollaborations. The leading systematic error of this result comes from the\nlattice discretization. This result is consistent with previous determinations.",
        "positive": "Three Dimensional N=2 Supersymmetry on the Lattice: We show how 3-dimensional, N=2 supersymmetric theories, including super QCD\nwith matter fields, can be put on the lattice with existing techniques, in a\nway which will recover supersymmetry in the small lattice spacing limit.\nResidual supersymmetry breaking effects are suppressed in the small lattice\nspacing limit by at least one power of the lattice spacing a."
    },
    {
        "anchor": "The Color--Flavor Transformation of induced QCD: The Zirnbauer's color-flavor transformation is applied to the $U(N_c)$\nlattice gauge model, in which the gauge theory is induced by a heavy chiral\nscalar field sitting on lattice sites. The flavor degrees of freedom can\nencompass several `generations' of the auxiliary field, and for each\ngeneration, remaining indices are associated with the elementary plaquettes\ntouching the lattice site. The effective, color-flavor transformed theory is\nexpressed in terms of gauge singlet matrix fields carried by lattice links. The\neffective action is analyzed for a hypercubic lattice in arbitrary dimension.\nWe investigate the corresponding d=2 and d=3 dual lattices. The saddle points\nequations of the model in the large-$N_c$ limit are discussed.",
        "positive": "Matrix product states and variational methods applied to critical\n  quantum field theory: We study the second-order quantum phase-transition of massive real scalar\nfield theory with a quartic interaction ($\\phi^4$ theory) in (1+1) dimensions\non an infinite spatial lattice using matrix product states (MPS). We introduce\nand apply a naive variational conjugate gradient method, based on the\ntime-dependent variational principle (TDVP) for imaginary time, to obtain\napproximate ground states, using a related ansatz for excitations to calculate\nthe particle and soliton masses and to obtain the spectral density. We also\nestimate the central charge using finite-entanglement scaling. Our value for\nthe critical parameter agrees well with recent Monte Carlo results, improving\non an earlier study which used the related DMRG method, verifying that these\ntechniques are well-suited to studying critical field systems. We also obtain\ncritical exponents that agree, as expected, with those of the transverse Ising\nmodel. Additionally, we treat the special case of uniform product states (mean\nfield theory) separately, showing that they may be used to investigate\nnon-critical quantum field theories under certain conditions."
    },
    {
        "anchor": "A quadrature-based eigensolver with a Krylov subspace method for shifted\n  linear systems for Hermitian eigenproblems in lattice QCD: We consider a quadrature-based eigensolver to find eigenpairs of Hermitian\nmatrices arising in lattice quantum chromodynamics. To reduce the computational\ncost for finding eigenpairs of such Hermitian matrices, we propose a new\ntechnique for solving shifted linear systems with complex shifts by means of\nthe shifted CG method. Furthermore using integration paths along horizontal\nlines corresponding to the real axis of the complex plane, the number of\niterations for the shifted CG method is also reduced. Some numerical\nexperiments illustrate the accuracy and efficiency of the proposed method by\ncomparison with a conventional method.",
        "positive": "Perturbative Study of the Supersymmetric Lattice Theory from Matrix\n  Model: We study the lattice model for the supersymmetric Yang-Mills theory in two\ndimensions proposed by Cohen, Kaplan, Katz, and Unsal. We re-examine the formal\nproof for the absence of susy breaking counter terms as well as the stability\nof the vacuum by an explicit perturbative calculation for the case of U(2)\ngauge group. Introducing fermion masses and treating the bosonic zero momentum\nmode nonperturbatively, we avoid the infra-red divergences in the perturbative\ncalculation. As a result, we find that there appear mass counter terms for\nfinite volume which vanish in the infinite volume limit so that the theory\nneeds no fine-tuning. We also find that the supersymmetry plays an important\nrole in stabilizing the lattice space-time by the deconstruction."
    },
    {
        "anchor": "One loop matching factors for staggered bilinear operators with improved\n  glue: We present results for matching factors for bilinear operators composed of\nHYP-smeared staggered fermions and constructed using HYP-smeared fat links. The\nmatching factors are calculated perturbatively at one-loop order. The new\nfeature of our calculation compared to previous work on HYP-smeared staggered\nfermions is the use of the Symanzik-improved gluon propagator, which allows our\nresults to be applied to our ongoing simulations based on configurations\ngenerated by the MILC collaboration. We address the issue of the relative\nefficiency of various improvement schemes in reducing one-loop corrections to\nthe matching factors.",
        "positive": "Energy--momentum tensor on the lattice: recent developments: It is conceivable that the construction of the energy--momentum tensor (EMT)\nin lattice field theory enlarges our ability in lattice field theory and also\ndeepens our understanding on EMT at the non-pertubative level. In this talk, I\nwill review recent developments in this enterprise."
    },
    {
        "anchor": "The properties of $D1$-branes from lattice super Yang--Mills theory\n  using gauge/gravity duality: The two-dimensional supersymmetric Yang-Mills (SYM) theory with sixteen\nsupercharges at large $N$ and strong 't~Hooft coupling is conjectured to be\ndual to certain supergravity solutions in the decoupling limit. We discretize\nthe gauge theory preserving a subset of supersymmetries on the lattice. Based\non the choice of a point in the moduli space for the expansion of the gauge\nlinks to target the correct continuum theory, one ends up with different\nlattice geometries. In our previous work, we explored the free energy and the\nphase structure on a skewed torus corresponding to $A_{2}^{*}$ lattice\ngeometry. Here, we will consider square lattice and calculate the free energy,\nequation of state and speed of sound in this strongly coupled supersymmetric\nplasma. Since there is no shear viscosity in two dimensions, we comment on the\nexpectations for the bulk viscosity from the calculations on the dual\nsupergravity side, which unlike the conformal $\\mathcal{N}=4$ SYM case does not\nvanish and is proportional to the trace of energy-momentum tensor.",
        "positive": "Gluon flux-tube distribution and linear confinement in baryons: We have observed the formation of gluon flux-tubes within baryons using\nlattice QCD techniques. A high-statistics approach, based on translational and\nrotational symmetries of the four-dimensional lattice, enables us to observe\ncorrelations between vacuum action density and quark positions in a completely\ngauge independent manner. This contrasts with earlier studies which used\ngauge-dependent smoothing techniques. We used 200 O(a^2) improved quenched QCD\ngauge-field configurations on a 16^3x32 lattice with a lattice spacing of 0.123\nfm. In the presence of static quarks flux tubes representing the suppression of\ngluon-field fluctuations are observed. We have analyzed 11 L-shapes and 8 T and\nY shapes of varying sizes in order to explore a variety of flux-tube\ntopologies, including the ground state. At large separations, Y-shape flux-tube\nformation is observed. T-shaped paths are observed to relax towards a Y-shaped\ntopology, whereas L-shaped paths give rise to a large potential energy. We do\nnot find any evidence for the formation of a Delta-shaped flux-tube (empty\ntriangle) distribution. However, at small quark separations, we observe an\nexpulsion of gluon-field fluctuations in the shape of a filled triangle with\nmaximal expulsion at the centre of the triangle. Having identified the precise\ngeometry of the flux distribution, we are able to perform quantitative\ncomparison between the length of the flux-tube and the associated static quark\npotential. For every source configuration considered we find a universal string\ntension, and conclude that, for large quark separations, the ground state\npotential is that which minimizes the length of the flux-tube. The flux tube\nradius of the baryonic ground state potential is found to be 0.38 \\pm 0.03 fm,\nwith vacuum fluctuations suppressed by 7.2 \\pm 0.6 %."
    },
    {
        "anchor": "Large N reduction on a twisted torus: We consider SU(N) lattice gauge theory at infinite N defined on a torus with\na CP invariant twist. Massless fermions are incorporated in an elegant way,\nwhile keeping them quenched. We present some numerical results which suggest\nthat twisting can make numerical simulations of planar QCD more efficient.",
        "positive": "Improved Algorithm for Bosonized Fermion Determinant: Following the line of \\cite{AS} we propose an improved algorithm which allows\nto calculate a D-dimensional fermion determinant integrating the exponent of\nD+1 dimensional Hermitean bosonic action. For a finite extra dimension the\ncorrections decrease exponentially."
    },
    {
        "anchor": "Scaling of cluster fluctuations in two-dimensional q=5 and 7 state Potts\n  models: The scaling behavior of fluctuations in cluster size is studied in q=5 and 7\nstate Potts models. This quantity exhibits scaling behavior on small lattices\nwhere the scaling of local operators like energy fluctuations and Binder\ncumulant can not be expected.",
        "positive": "Exploring the Critical Points in QCD with Multi-Point Pad\u00e9 and Machine\n  Learning Techniques in (2+1)-flavor QCD: Using simulations at multiple imaginary chemical potentials for\n$(2+1)$-flavor QCD, we construct multi-point Pad\\'e approximants. We determine\nthe singularties of the Pad\\'e approximants and demonstrate that they are\nconsistent with the expected universal scaling behaviour of the Lee-Yang edge\nsingularities. We also use a machine learning model, Masked Autoregressive\nDensity Estimator (MADE), to estimate the density of the Lee-Yang edge\nsingularities at each temperature. This ML model allows us to interpolate\nbetween the temperatures. Finally, we extrapolate to the QCD critical point\nusing an appropriate scaling ansatz."
    },
    {
        "anchor": "Multiple-channel generalization of Lellouch-Luscher formula: We generalize the Lellouch-Luscher formula, relating weak matrix elements in\nfinite and infinite volumes, to the case of multiple strongly-coupled decay\nchannels into two scalar particles. This is a necessary first step on the way\nto a lattice QCD calculation of weak decay rates for processes such as D -> pi\npi and D -> KK. We also present a field theoretic derivation of the\ngeneralization of Luscher's finite volume quantization condition to multiple\ntwo-particle channels. We give fully explicit results for the case of two\nchannels, including a form of the generalized Lellouch-Luscher formula\nexpressed in terms of derivatives of the energies of finite volume states with\nrespect to the box size. Our results hold for arbitrary total momentum and for\ndegenerate or non-degenerate particles.",
        "positive": "Preliminary results of the heavy-light meson spectrum using chirally\n  improved light quarks: Using a ``wall'' of quark point sources, we invert the chirally improved\nDirac operator to create an ``incoherent'' collection of quark propagators\nwhich originate from all spatial points of the source time slice. The\nlowest-order NRQCD approximation is used to create heavy-quark propagators from\nthe same wall source. However, since the numerical cost involved in computing\nsuch heavy-quark propagators is low, we are able to use a number of source\ngauge paths to establish coherence between the heavy and light quarks at\nseveral spatial separations. The resulting collection of heavy-light meson\ncorrelators is analyzed to extract the corresponding mass spectrum."
    },
    {
        "anchor": "Study of the Finite Density State based on SU(2) Lattice QCD: We report our recent numerical studies on two-color QCD with Wilson fermions.\nFirst the phase structure of the system in (kappa,mu)-plane is analyzed by\nmeasuring Polyakov line, baryon number density, gluon energy density and\nPolyakov line susceptibility. Then meson and baryon (di-quark) propagators are\ninvestigated. We find that the vector meson mass decreases near mu_c. This\nphenomena can be related to the low-mass lepton-pair enhancement observed in\nCERES experiment. Since our lattice is small, in order to confirm the results,\nwe calculate both periodic and anti-periodic boundary condition cases.\nPreliminary calculations of color averaged, symmetric and anti-symmetric forces\nof qq system obtained from Polyakov line correlations, and gluon propagators\nare reported.",
        "positive": "Delta-baryon electromagnetic form factors in lattice QCD: We develop techniques to calculate the four Delta electromagnetic form\nfactors using lattice QCD, with particular emphasis on the sub-dominant\nelectric quadrupole form factor that probes deformation of the Delta. Results\nare presented for pion masses down to approximately 350 MeV for three cases:\nquenched QCD, two flavors of dynamical Wilson quarks, and three flavors of\nquarks described by a mixed action combining domain wall valence quarks and\ndynamical staggered sea quarks. The magnetic moment of the Delta is chirally\nextrapolated to the physical point and the Delta charge density distributions\nare discussed."
    },
    {
        "anchor": "Tensor network formulation of two dimensional gravity: We show how to formulate a lattice gauge theory whose naive continuum limit\ncorresponds to two-dimensional (Euclidean) quantum gravity including a positive\ncosmological constant. More precisely the resultant continuum theory\ncorresponds to gravity in a first-order formalism in which the local frame and\nspin connection are treated as independent fields. Recasting this lattice\ntheory as a tensor network allows us to study the theory at strong coupling\nwithout encountering a sign problem. In two dimensions this tensor network is\nexactly soluble and we show that the system has a series of critical points\nthat occur for pure imaginary coupling and are associated with first order\nphase transitions. We then augment the action with a Yang-Mills term which\nallows us to control the lattice spacing and show how to apply the TRG to\ncompute the free energy and look for critical behavior. Finally we perform an\nanalytic continuation in the gravity coupling in this extended model and show\nthat its critical behavior in a certain scaling limit depends only on the\ntopology of the underlying lattice. We also show how the lattice gauge theory\ncan be naturally generalized to generate the Polyakov or Liouville action for\ntwo dimensional quantum gravity.",
        "positive": "Improving the topological charge density operator on the lattice: We analyze the properties of a class of improved lattice topological charge\ndensity operators, constructed by a smearing-like procedure. By optimizing the\nchoice of the parameters introduced in their definition, we find operators\nhaving (i) a much better statistical behavior as estimators of the topological\ncharge density on the lattice, i.e. much less noisy; (ii) a multiplicative\nrenormalization much closer to one; (iii) a large suppression of the\nperturbative tail in the corresponding lattice topological susceptibility."
    },
    {
        "anchor": "Connected Correlators in Quantum Gravity: We discuss the concept of connected, reparameterization invariant matter\ncorrelators in quantum gravity. We analyze the effect of discretization in two\nsolvable cases: branched polymers and two-dimensional simplicial gravity. In\nboth cases the naively defined connected correlators for a fixed volume display\nan anomalous behavior, which could be interpreted as a long-range order. We\nsuggest that this is in fact only a highly non-trivial finite-size effect and\npropose an improved definition of the connected correlator, which reduces the\neffect. Using this definition we illustrate the appearance of a long-range spin\norder in the Ising model on a two-dimensional random lattice in an external\nmagnetic field $H$, when $H \\to 0$ and $\\beta=\\beta_C$.",
        "positive": "Towards Partial Compositeness on the Lattice: Baryons with Fermions in\n  Multiple Representations: We describe our recent lattice study of SU(4) gauge theory with fermions in\nthe fundamental and sextet representations. In this theory, a new type of\nbaryon consists of quarks in both representations. The spectrum of these\n\"chimera baryons\" has a straightforward interpretation in terms of a\nnon-relativistic quark model based on SU(4). Our results are particularly\nrelevant to composite Higgs models in which the top quark is partially\ncomposite."
    },
    {
        "anchor": "Local Polyakov loop domains and their fractality: We discuss properties of local Polyakov loops in the deconfinement transition\nof SU(3) lattice gauge theory at finite temperature using the fixed scale\napproach. In particular we study spatial clusters where local Polyakov loops\nhave phases near the same center elements of the gauge group. We present\nresults for various properties of the center clusters, e.g., their percolation\nprobability or their fractality and discuss the physical implications for\ntemperatures below and above the phase transition.",
        "positive": "Composite bosonic baryon dark matter on the lattice: SU(4) baryon\n  spectrum and the effective Higgs interaction: We present the spectrum of baryons in a new SU(4) gauge theory with\nfundamental fermion constituents. The spectrum of these bosonic baryons is of\nsignificant interest for composite dark matter theories. Here, we compare the\nspectrum and properties of SU(3) and SU(4) baryons, and then compute the\ndark-matter direct detection cross section via Higgs boson exchange for\nTeV-scale composite dark matter arising from a confining SU(4) gauge sector.\nComparison with the latest LUX results leads to tight bounds on the fraction of\nthe constituent-fermion mass that may arise from electroweak symmetry breaking.\nLattice calculations of the dark matter mass spectrum and the Higgs-dark matter\ncoupling are performed on quenched $16^{3} \\times 32$, $32^{3} \\times 64$,\n$48^{3} \\times 96$, and $64^{3} \\times128$ lattices with three different\nlattice spacings, using Wilson fermions with moderate to heavy pseudoscalar\nmeson masses. Our results lay a foundation for future analytic and numerical\nstudy of composite baryonic dark matter."
    },
    {
        "anchor": "Renormalization group invariant average momentum of non-singlet parton\n  densities: We compute, within the Schr\\\"odinger functional scheme, a renormalization\ngroup invariant renormalization constant for the first moment of the\nnon-singlet parton distribution function. The matching of the results of our\nnon-perturbative calculation with the ones from hadronic matrix elements allows\nus to obtain eventually a renormalization group invariant average momentum of\nnon-singlet parton densities, which can be translated into a preferred scheme\nat a specific scale.",
        "positive": "Finite Volume Dependence of the Quark-Antiquark Vacuum Expectation Value: A general formula is derived for the finite volume dependence of vacuum\nexpectation values analogous to Luscher's formula for the masses. The result\ninvolves no integrals over kinematic quantities and depends only on the matrix\nelement between pions at zero momentum transfer thus presenting a new way to\ncalculate the latter, i.e. pion sigma terms.\n  The full order $p^6$ correction to the vacuum condensate $<\\bar q q>$ is\nevaluated and compared with the result from the Luscher formula. Due to the\nsize of the $p^6$ result no conclusion about the accuracy of the Luscher\nformula can be drawn."
    },
    {
        "anchor": "Screening mass responses to the chemical potential at finite temperature: Responses to chemical potential of the pseudoscalar meson screening mass and\nthe chiral condensate in lattice QCD are investigated. On a $16 \\times 8^2\n\\times \\4$ lattice with two flavors of staggered quarks the first and second\nresponses below and above $T_c$ are evaluated. Different behavior in the low\nand the high temperature phases are observed, which may be explained as a\nconsequence of the chiral symmetry breaking and restoration.",
        "positive": "Multicanonical multigrid Monte Carlo method and effective\n  autocorellation time: We report tests of the recently proposed multicanonical multigrid Monte Carlo\nmethod for the two-dimensional $\\Phi^4$ field theory. Defining an effective\nautocorrelation time we obtain real time improvement factors of about one order\nof magnitude compared with standard multicanonical simulations."
    },
    {
        "anchor": "Spectrum and scaling in a strongly coupled fermion-gauge-scalar model: The strongly coupled lattice gauge models show an interesting mechanism of\ndynamical mass generation. If a suitable continuum limit can be found, one may\nthink of it as an alternative to the Higgs mechanism. We present data on the\nspectrum, obtained in the model with U(1) gauge symmetry with dynamical\nfermions. They indicate that the fermion mass scales in the vicinity of the\nwhole chiral phase transition line. In contrast to this, the composite scalar\nboson mass seems to get small only in the region near the endpoint E of the\nHiggs phase transition. Thus this point is the most interesting candidate for\napproaching the continuum limit. The masses of fermion--antifermion bound\nstates are also discussed.",
        "positive": "QCD at non-zero temperature from the lattice: I review the status of lattice QCD calculations at non-zero temperature.\nAfter summarizing what is known about the equilibrium properties of strongly\ninteracting matter, I discuss in more detail recent results concerning the\nquark-mass dependence of the thermal phase transition and the status of\ncalculations of non-equilibrium properties."
    },
    {
        "anchor": "Path Integral Monte Carlo Approach to the U(1) Lattice Gauge Theory in\n  (2+1) Dimensions: Path Integral Monte Carlo simulations have been performed for U(1) lattice\ngauge theory in (2+1) dimensions on anisotropic lattices. We extractthe static\nquark potential, the string tension and the low-lying \"glueball\" spectrum.The\nEuclidean string tension and mass gap decrease exponentially at weakcoupling in\nexcellent agreement with the predictions of Polyakov and G{\\\" o}pfert and Mack,\nbut their magnitudes are five times bigger than predicted. Extrapolations are\nmade to the extreme anisotropic or Hamiltonian limit, and comparisons are made\nwith previous estimates obtained in the Hamiltonian formulation.",
        "positive": "The deconfining phase transition in SU(N) gauge theories: We report on our ongoing investigation of the deconfining phase transition in\nSU(4) and SU(6) gauge theories. We calculate the critical couplings while\ntaking care to avoid the influence of a nearby bulk phase transition. We\ndetermine the latent heat of the phase transition and investigate the order and\nthe strength of the transition at large N. We also report on our determination\nof the critical temperature expressed in units of the string tension in the\nlarge N limit."
    },
    {
        "anchor": "Pion Nucleon Scattering: Some Results from Lattice QCD: Including the meson-baryon (5 quark) intermediate states in a lattice\nsimulation is challenging. However, it is important in order to obtain the\ncorrect energy eigenstates and to relate them to scattering phase shifts.\nRecent results for the negative parity nucleon channel and the problem of\nbaryonic resonances in lattice calculations are discussed.",
        "positive": "Simplicial Quantum Gravity on a Computer: We describe a method of Monte-Carlo simulations of simplicial quantum gravity\ncoupled to matter fields. We concentrate mainly on the problem of implementing\neffectively the random, dynamical triangulation and building in a\ndetailed-balance condition into the elementary transformations of the\ntriangulation. We propose a method of auto-tuning the parameters needed to\nbalance simulations of the canonical ensemble. This method allows us to prepare\na whole set of jobs and therefore is very useful in systematic determining the\nphase diagram in two dimensional coupling space. It is of particular importance\nwhen the jobs are run on a parallel machine."
    },
    {
        "anchor": "An overview of (selected) recent results in finite-temperature lattice\n  QCD: I discuss recent results on lattice QCD calculations with the main emphasis\non the thermodynamics of the crossover region, restoration of the chiral\nsymmetry and fluctuations of conserved charges as indicator of deconfinement,\nthat may also be used to determine the chemical freeze-out conditions in\nheavy-ion collision experiments.",
        "positive": "Manifestation of Confinement in the Gluon propagator: The gluon propagator in Landau gauge is calculated on the lattice for SU(2)\ngauge theory. In particular the manifestation of confinement in the gluon\npropagator is studied. Removing the confining center vortices from the\nYang-Mills ensemble leads to a drastic reduction of the gluonic form factor in\nthe intermediate momentum regime."
    },
    {
        "anchor": "Flavor Twisted Boundary Conditions in the Breit Frame: We use a generalization of chiral perturbation theory to account for the\neffects of flavor twisted boundary conditions in the Breit frame. The relevant\nframework for two light flavors is an SU(6|4) partially quenched theory, where\nthe extra valence quarks differ only by their boundary conditions. Focusing on\nthe pion electromagnetic form factor, finite volume corrections are calculated\nat next-to-leading order in the chiral expansion and are estimated to be small\non current lattices.",
        "positive": "Transversal and longitudinal gluon spectral functions from twisted mass\n  lattice QCD with $N_f=2+1+1$ flavors: I report on the first application of a novel, generalized Bayesian\nreconstruction (BR) method for spectral functions to the characterization of\nQCD constituents. These spectral functions find applications in off-shell\nkinetics of the quark-gluon plasma and in calculations of transport\ncoefficients. The new BR method is applied to Euclidean propagator data,\nobtained in Landau gauge on lattices with $N_f=2+1+1$ dynamical flavors by the\n\"twisted mass at finite temperature\" (tmfT) collaboration. The deployed\nreconstruction method is designed for spectral functions that can exhibit\npositivity violation (opposed to that of hadronic bound states). The\ntransversal and longitudinal gluon spectral functions show a robust structure\ncomposed of quasiparticle peak and a negative trough. Characteristic\ndifferences between the hadronic and the plasma phase and between the two\nchannels become visible. We obtain the temperature dependence of the\ntransversal and longitudinal gluon masses."
    },
    {
        "anchor": "Thimble regularization at work besides toy models: from Random Matrix\n  Theory to Gauge Theories: Thimble regularization as a solution to the sign problem has been\nsuccessfully put at work for a few toy models. Given the non trivial nature of\nthe method (also from the algorithmic point of view) it is compelling to\nprovide evidence that it works for realistic models. A Chiral Random Matrix\ntheory has been studied in detail. The known analytical solution shows that the\nmodel is non-trivial as for the sign problem (in particular, phase quenched\nresults can be very far away from the exact solution). This study gave us the\nchance to address a couple of key issues: how many thimbles contribute to the\nsolution of a realistic problem? Can one devise algorithms which are robust as\nfor staying on the correct manifold? The obvious step forward consists of\napplications to gauge theories.",
        "positive": "Heavy-Light Decay Constants: Conclusions from the Wilson Action: We report on the results of a MILC collaboration calculation of $f_B$,\n$f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios. We discuss the most important\nerrors in more detail than we have elsewhere."
    },
    {
        "anchor": "Monopoles and Lyapunov Exponents in U(1) Lattice Gauge Theory: U(1) gauge fields are decomposed into a monopole and photon part across the\nphase transition from the confinement to the Coulomb phase. We analyze the\nleading Lyapunov exponents of such gauge field configurations on the lattice\nwhich are initialized by quantum Monte Carlo simulations. We observe a strong\nrelation between the sizes of the monopole density and the Lyapunov exponent.\nEvidence is found that monopole fields stay chaotic in the continuum whereas\nthe photon fields are regular.",
        "positive": "Thermal Correlators in the \u03c1 channel of two-flavor QCD: We present a lattice QCD calculation with two dynamical flavors of the\nisovector vector correlator in the high-temperature phase. We analyze the\ncorrelator in terms of the associated spectral function, for which we review\nthe theoretical expectations. In our main analysis, we perform a fit for the\ndifference of the thermal and vacuum spectral functions, and we use an exact\nsum rule that constrains this difference. We also perform a direct fit for the\nthermal spectral function, and obtain good agreement between the two analyses\nfor frequencies below the two-pion threshold. Under the assumption that the\nspectral function is smooth in that region, we give an estimate of the\nelectrical conductivity."
    },
    {
        "anchor": "Effective Potential for Scalar Field in Three Dimensions: Ising Model in\n  the Ferromagnetic Phase: We compute the effective potential $V_{\\rm eff}(\\phi)$ for one-component real\nscalar field $\\phi$ in three Euclidean dimensions (3D) in the case of\nspontaneously broken symmetry, from the Monte Carlo simulation of the 3D Ising\nmodel in external field at temperatures approaching the phase transition from\nbelow. We study probability distributions of the order parameter on the\nlattices from $30^3$ to $74^3$, at $L/\\xi \\approx 10$. We find that, in close\nanalogy with the symmetric case, $\\phi^6$ plays an important role: $V_{\\rm\neff}(\\phi)$ is very well approximated by the sum of $\\phi^2$, $\\phi^4$ and\n$\\phi^6$ terms. An unexpected feature is the negative sign of the $\\phi^4$\nterm. As close to the continuum limit as we can get ($\\xi \\approx 7.2$), we\nobtain\n  $$ {\\cal L}_{\\rm eff} \\approx\n  {1 \\over 2} \\partial_\\mu \\phi \\partial_\\mu \\phi +\n  1.7 (\\phi^2 - \\eta^2)^2 (\\phi^2 + \\eta^2). $$\n  We also compute several universal coupling constants and ratios, including\nthe combination of critical amplitudes $C^- (f_1^-)^{-3} B^{-2}$.",
        "positive": "Gluonic profile of the static baryon at finite temperature: The gluon flux distribution of a static three quark system has been revealed\nat finite temperature in the pure SU(3) Yang-Mills theory. An action density\noperator is correlated with three Polyakov loops representing the baryonic\nstate at a temperatures near the end of the QCD plateau, T/T_c = 0.8, and\nanother just before the deconfinement point, T/T_c = 0.9. The flux\ndistributions at short distance separations between the quarks display an\naction-density profile consistent with a filled Delta shape iso-surface.\nHowever the Delta-shaped action iso-surface distributions are found to persist\neven at large inter-quark separations for both temperatures. The action density\ndistribution in the quark plane exhibits a nonuniform pattern for all quark\nseparations considered. This result contrasts the well-known Y-shaped uniform\naction density gluonic-flux profile obtained using the Wilson-loop as a quark\nsource operator at zero temperature. We systematically measure and compare the\nmain aspects of the profile of the flux distribution at the two considered\ntemperature scales for three sets of isosceles triangle quark configurations.\nThe radii, amplitudes and rate of change of the width of the flux distribution\nare found to reverse their behavior as the temperature increase from the end of\nthe QCD plateau region towards the deconfinement point. Remarkably, we find the\nmean square width of the flux distribution shrinks and localizes for quark\nseparations larger than 1.0 fm at T/T_c = 0.8 which results in an identifiable\nY-shaped radius profile. Near the deconfinement point, the action-density\ndelocalizes and the width broadens linearly at large quark separations."
    },
    {
        "anchor": "Chiral Fermions and Multigrid: Lattice regularization of chiral fermions is an important development of the\ntheory of elementary particles. Nontheless, brute force computer simulations\nare very expensive, if not prohibitive. In this letter I exploit the\nnon-interacting character of the lattice theory in the flavor space and propose\na multigrid approach for the simulation of the theory. Already a two-grid\nalgorithm saves an order of magnitude of computer time for fermion propagator\ncalculations.",
        "positive": "Roberge-Weiss transition in $N_f=2$ QCD with staggered fermions and\n  $N_\u03c4=6$: The QCD phase diagram at imaginary chemical potential exhibits a rich\nstructure and studying it can constrain the phase diagram at real values of the\nchemical potential. Moreover, at imaginary chemical potential standard\nnumerical techniques based on importance sampling can be applied, since no sign\nproblem is present. In the last decade, a first understanding of the QCD phase\ndiagram at purely imaginary chemical potential has been developed, but most of\nit is so far based on investigations on coarse lattices ($N_\\tau=4$,\n$a=0.3\\:$fm). Considering the $N_f=2$ case, at the Roberge-Weiss critical value\nof the imaginary chemical potential, the chiral/deconfinement transition is\nfirst order for light/heavy quark masses and second order for intermediate\nvalues of the mass: there are then two tricritical masses, whose position\nstrongly depends on the lattice spacing and on the discretization. On\n$N_\\tau=4$, we have the chiral $m_\\pi^{\\text{tric.}}=400\\:$MeV with unimproved\nstaggered fermions and $m_\\pi^{\\text{tric.}}\\gtrsim900\\:$MeV with unimproved\npure Wilson fermions. Employing finite size scaling we investigate the change\nof this tricritical point between $N_\\tau=4$ and $N_\\tau=6$ as well as between\nWilson and staggered discretizations."
    },
    {
        "anchor": "Yukawa model on a lattice: two body states: We present first results of the solutions of the Yukawa model as a Quantum\nField Theory (QFT) solved non perturbatively with the help of lattice\ncalculations. In particular we will focus on the possibility of binding two\nnucleons in the QFT, compared to the non relativistic result.",
        "positive": "Kaon semileptonic form factors in QCD with exact chiral symmetry: We report on our calculation of the kaon semileptonic form factors in Nf=2+1\nlattice QCD. Chiral symmetry is exactly preserved by using the overlap quark\naction for a straightforward comparison with chiral perturbation theory (ChPT).\nWe simulate three pion masses down to 290 MeV at a single lattice spacing of\n0.11 fm and at a strange quark mass very close to its physical value. The form\nfactors near zero momentum transfer are precisely calculated by using the\nall-to-all propagator and twisted boundary conditions. We compare the\nnormalizations and slopes of the form factors with ChPT and experiments."
    },
    {
        "anchor": "QED$_3$ on a space-time lattice: compact versus noncompact formulation: We study quantum electrodynamics in a (2+1)-dimensional space-time with two\nflavors of dynamical fermions by numerical simulations on the lattice. We\ndiscretize the theory using both the compact and the noncompact formulations\nand analyze the behavior of the chiral condensate and of the monopole density\nin the finite lattice regime as well as in the continuum limit. By comparing\nthe results obtained with the two approaches, we draw some conclusions about\nthe possible equivalence of the two lattice formulations in the continuum\nlimit.",
        "positive": "Regularizations, Anomalies and Fermion Number Non-Conservation in Chiral\n  Gauge Theories: We study how fermion number conservation fails in fermion number preserving\nregularization schemes. We show that the fermion number have to be carried by\nthe gauge field configurations with non-zero winding number in this scheme and\nthis fermion number is not conserved in the presence of instantons. We also\nconsider other types of regularization scheme which have different global\nsymmetries. In particular, we point out that the fermion number is conserved in\nthe lattice chiral gauge theories with the Wilson-Yukawa coupling."
    },
    {
        "anchor": "A new method for the beta function in the chiral symmetry broken phase: We describe a new method to determine non-perturbatively the beta function of\na gauge theory using lattice simulations in the p-regime of the theory. This\ncomplements alternative measurements of the beta function working directly at\nzero fermion mass and bridges the gap between the weak coupling perturbative\nregime and the strong coupling regime relevant to the mass spectrum of the\ntheory. We apply this method to ${\\mathrm {SU(3)} }$ gauge theory with two\nfermion flavors in the 2-index symmetric (sextet) representation. We find that\nthe beta function is small but non-zero at the renormalized coupling value $g^2\n= 6.7$, consistent with our previous independent investigation using\nsimulations directly at zero fermion mass. The model continues to be a very\ninteresting explicit realization of the near-conformal composite Higgs paradigm\nwhich could be relevant for Beyond Standard Model phenomenology.",
        "positive": "A Rigourous Treatment of the Lattice Renormalization Problem of F_B: The $B$-meson decay constant can be measured on the lattice using a $1/m_b$\nexpansion. To relate the physical quantity to Monte Carlo data one has to know\nthe renormalization coefficient, $Z$, between the lattice operators and their\ncontinuum counterparts. We come back to this computation to resolve\ndiscrepancies found in previous calculations. We define and discuss in detail\nthe renormalization procedure that allows the (perturbative) computation of\n$Z$. Comparing the one-loop calculations in the effective Lagrangian approach\nwith the direct two-loop calculation of the two-point $B$-meson correlator in\nthe limit of large $b$-quark mass, we prove that the two schemes give\nconsistent results to order $\\alpha_s$. We show that there is, however, a\nrenormalization prescription ambiguity that can have sizeable numerical\nconsequences. This ambiguity can be resolved in the framework of an $O(a)$\nimproved calculation, and we describe the correct prescription in that case.\nFinally we give the numerical values of $Z$ that correspond to the different\ntypes of lattice approximations discussed in the paper."
    },
    {
        "anchor": "Kazakov-Migdal Induced Gauge Theory and the Coupling of 2D Quantum\n  Gravity to D=1 Matter: Recently Kazakov and Migdal proposed a new approach to the large $N$ limit of\nSU(N) gauge theories which could hopefully describe the asymptotically free\nfixed point of QCD in 4 dimensions. In this contribution we review the exact\nsolution of their model in the case of a $d=1$ compactified lattice and its\nconnection with the partition function of the vortex-free sector of the d=1\ncompactified bosonic string. Some new results on the addition of a linear term\nin the K-M model and on the SU(N) restriction of the general U(N) model are\nalso presented.",
        "positive": "Dirac and Gor'kov spectra in two color QCD with chemical potential: We analyze the eigenvalue spectrum of the staggered Dirac matrix in two-color\nQCD at nonzero baryon density when the eigenvalues become complex. The\nquasi-zero modes and their role for chiral symmetry breaking and the\ndeconfinement transition are examined. The bulk of the spectrum and its\nrelation to quantum chaos is considered. A comparison with predictions from\nrandom matrix theory is presented. An analogous analysis is performed for the\nspectrum of the Gor'kov representation of the fermionic action."
    },
    {
        "anchor": "$Z_N$ symmetry in $SU(N)$ gauge theories: We study $Z_N$ symmetry in $SU(N)$ gauge theories in the presence of matter\nfields in the fundamental representation, by restricting the lattice partition\nfunction integration to matter fields which are uniform in spatial directions\nand gauge fields with vanishing spatial components. In this approximation the\ngauge matter field interaction effectively reduces to a 1-dimensional gauged\nchain. This makes analytical calculations of the matter field contribution to\nthe Polyakov loop free energy possible. We show that in the limit of large\nnumber of temporal sites the explicit breaking of $Z_N$ symmetry in this free\nenergy vanishes, driven by dominance of the density of states. We argue that\nthe spatial links as well as the spatial modes of the matter fields determine\nthe boundaries separating regions where $Z_N$ symmetry is realised from rest of\nthe phase diagram.",
        "positive": "New results on heavy hadron spectroscopy with NRQCD: We present results for the spectrum of b-bbar bound states in the quenched\napproximation for three different values of the lattice spacing. Results for\nspin-independent splittings are shown to have good scaling behaviour;\nspin-dependent splittings are more sensitive to discretisation effects. We\ndiscuss what needs to be done to match the experimental spectrum."
    },
    {
        "anchor": "Finite-density QCD, $\\mathcal{PT}$ symmetry, and dual algorithms: Finite-density QCD and many other field theories with sign problems have a\n$\\mathcal{PT}$-type symmetry. After a brief introduction to\n$\\mathcal{PT}$-symmetric field theories, a real dual representation for\n$\\mathcal{PT}$-symmetric scalar field theories with complex actions is derived.\nWe show that $\\mathcal{PT}$-symmetric field theories can exhibit exotic\nbehavior, including sinusoidally modulated propagators, disorder lines, and\nspatially inhomogeneous pattern-forming phases. We discuss the interplay of\nduality, $\\mathcal{PT}$-symmetry and pattern formation using a $\\phi^4$ model\nand $Z(N)$ spin model with sign problems as examples. These behaviors may occur\nin finite-density QCD and related models.",
        "positive": "Generalized Parton Distributions from Lattice QCD: In recent years, there has been a breakthrough in lattice calculations of\n$x$-dependent partonic distributions. This encompasses also distributions\ndescribing the 3D structure of the nucleon, such as generalized parton\ndistributions (GPDs). We report a new method of accessing GPDs in asymmetric\nframes of reference, relying on a novel Lorentz-covariant parametrization of\nthe accessed off-forward matrix elements in boosted nucleon states. The\napproach offers the possibility of computationally more efficient determination\nof the full parameter dependence of GPDs and as such, it can contribute to\nbetter understanding of nucleon's structure."
    },
    {
        "anchor": "The Perturbative Method Fails in Non-Abelian Models: It is shown that perturbation theory in $2D$ nonlinear $\\sigma$-models as\nwell gauge theories in dimension $D\\geq 2$ produces answers that depend on\nboundary conditions even after the infinite volume limit has been taken. This\nunphysical phenomenon occurs only in the non-Abelian versions of those models,\nstarting at $O(1/\\beta^2)$. It is not present in the true (nonperturbatively\ndefined) models and represents a failure of the perturbative method. It is\nrelated to a hitherto unnoticed type of low-lying excitation, dubbed\nsuper-instanton, that dominates the low-temperature (= weak coupling) regime of\nthese models.",
        "positive": "Extraction of multiple exponential signals from lattice correlation\n  functions: We present a fast and simple algorithm that allows the extraction of multiple\nexponential signals from the temporal dependence of correlation functions\nevaluated on the lattice including the statistical fluctuations of each signal\nand treating properly backward signals. The basic steps of the method are the\ninversion of appropriate matrices and the determination of the roots of an\nappropriate polynomial, constructed using discretized derivatives of the\ncorrelation function. The method is tested strictly using fake data generated\nassuming a fixed number of exponential signals included in the correlation\nfunction with a controlled numerical precision and within given statistical\nfluctuations. All the exponential signals together with their statistical\nuncertainties are determined exactly by the algorithm. The only limiting factor\nis the numerical rounding off. In the case of correlation functions evaluated\nby large-scale QCD simulations on the lattice various sources of noise, other\nthan the numerical rounding, can affect the correlation function and they\nrepresent the crucial factor limiting the number of exponential signals,\nrelated to the hadronic spectral decomposition of the correlation function,\nthat can be properly extracted. The algorithm can be applied to a large variety\nof correlation functions typically encountered in QCD or QCD+QED simulations on\nthe lattice, including the case of exponential signals corresponding to poles\nwith arbitrary multiplicity and/or the case of oscillating signals. The method\nis able to to detect the specific structure of the multiple exponential signals\nwithout any a priori assumption and it determines accurately the ground-state\nsignal without the need that the lattice temporal extension is large enough to\nallow the ground-state signal to be isolated."
    },
    {
        "anchor": "Convergence of chiral effective field theory: We formulate the expansion for the mass of the nucleon as a function of pion\nmass within chiral perturbation theory using a number of different ultra-violet\nregularisation schemes; including dimensional regularisation and various\nfinite-ranged regulators. Leading and next-to-leading order non-analytic\ncontributions are included through the standard one-loop Feynman graphs. In\naddition to the physical nucleon mass, the expansion is constrained by recent,\nextremely accurate, lattice QCD data obtained with two flavors of dynamical\nquarks. The extent to which different regulators can describe the chiral\nexpansion is examined, while varying the range of quark mass over which the\nexpansions are matched. Renormalised chiral expansion parameters are recovered\nfrom each regularisation prescription and compared. We find that the\nfinite-range regulators produce consistent, model-independent results over a\nwide range of quark mass sufficient to solve the chiral extrapolation problem\nin lattice QCD.",
        "positive": "Composition of the inclusive semi-leptonic decay of B meson: Utilizing the approach recently proposed for the inclusive semi-leptonic\ndecay rate on the lattice, we compute the differential decay rate of a $B_s$\nmeson for various kinematical channels. The results are compared with the\ncontributions from the ground states (D and D^*) as well as from the orbitally\nexcited states (D^**'s). The computation so far is carried out with an\nunphysically light bottom quark and strange spectator quark."
    },
    {
        "anchor": "Cho-Faddeev-Niemi decomposition of lattice Yang-Mills theory and\n  evidence of a novel magnetic condensation: We present the first implementation of the Cho--Faddeev--Niemi ecomposition\nof the SU(2) Yang-Mills field on a lattice. Our construction retains the color\nsymmetry (global SU(2) gauge invariance) even after a new type of Maximally\nAbelian gauge, as explicitly demonstrated by numerical simulations.",
        "positive": "The spectrum of closed loops of fundamental flux in D=2+1 SU(N) gauge\n  theories: We study the closed-string spectrum of SU(N) gauge theories in the\nfundamental representation in 2+1 dimensions. We calculate the energies of the\nlowest lying ~ 30 states using a large variety of operators characterised by\nthe quantum numbers of parity and longitudinal momentum. We find that our\nresults for the ground state are very well approximated by the Nambu-Goto (NG)\npredictions even for short strings. For the excited states, we observe\nsignificant deviations from the NG predictions only for very short strings and\nthey decrease rapidly with increasing string length. Finally, we see that\nNambu-Goto provides a much better description of our results than the effective\nstring theoretical predictions. We discuss the continuum and large-N limits."
    },
    {
        "anchor": "Nuclear modification of scalar, axial and tensor charges from lattice\n  QCD: Complete flavour decompositions of the scalar, axial and tensor charges of\nthe proton, deuteron, diproton and $^3$He at SU(3)-symmetric values of the\nquark masses corresponding to a pion mass $m_\\pi\\sim806$ MeV are determined\nusing lattice QCD. At the physical quark masses, the scalar charges constrain\nmean-field models of nuclei and the low-energy interactions of nuclei with\npotential dark matter candidates. The axial and tensor charges of nuclei\nconstrain their spin content, integrated transversity and the quark\ncontributions to their electric dipole moments. External fields are used to\ndirectly access the quark-line connected matrix elements of quark bilinear\noperators, and a combination of stochastic estimation techniques is used to\ndetermine the disconnected sea-quark contributions. Significant nuclear\nmodifications are found, with particularly large, O(10%), effects in the scalar\ncharges. Typically, these nuclear effects reduce the effective charge of the\nnucleon (quenching), although in some cases an enhancement is not excluded.\nGiven the size of the nuclear modifications of the scalar charges resolved\nhere, contributions from correlated multi-nucleon effects should be quantified\nin the analysis of dark matter direct-detection experiments using nuclear\ntargets.",
        "positive": "The Equation of State for Two Flavor QCD at Non-zero Chemical Potential: We present results of a simulation of QCD on a 4x16^3 lattice with 2\ncontinuum flavors of p4-improved staggered fermion with mass m/T=0.4.\nDerivatives of the thermodynamic grand potential with respect to quark chemical\npotential mu_q up to fourth order are calculated, enabling estimates of the\npressure, quark number density and associated susceptibilities as functions of\nmu_q via Taylor series expansion. Discretisation effects associated with\nvarious staggered fermion formulations are discussed in some detail. In\naddition it is possible to estimate the radius of convergence of the expansion\nas a function of temperature. We also discuss the calculation of energy and\nentropy densities which are defined via mixed derivatives of the thermodynamic\ngrand potential with respect to the bare couplings and quark masses."
    },
    {
        "anchor": "Light Quenched Hadron Spectrum and Decay Constants on different Lattices: In this paper we study O(2000) (quenched) lattice configurations from the APE\ncollaboration, for different lattice volumes and for 6.0 \\le beta \\le 6.4 using\nboth the Wilson and the SW-Clover fermion actions. We determine the light\nhadronic spectrum and meson decay constants and study the mesonic dispersion\nrelation. We extract the hadronic variable J and the strange quark mass in the\ncontinuum at the next-to-leading order obtaining m_s^{MSbar}(mu=2 GeV) = 122\n+/- 20 MeV. A study is made of their dependence on lattice spacing. We\nimplement a newly developed technique to extract the inverse lattice spacing\nusing data at the simulated values of the quark mass (i.e. at masses around the\nstrange quark mass).",
        "positive": "Confinement-deconfinement order parameters: We study numerically the monopole creation operator proposed recently by\nFrohlich and Marchetti. The operator is defined with the help of a three\ndimensional model which generates random Mandelstam strings. These strings\nimitate the Coulombic magnetic field around the monopole. We show that if the\nMandelstam strings are condensed the creation operator discriminates between\nthe phases with condensed and non--condensed monopoles in the Abelian Higgs\nmodel with the compact gauge field."
    },
    {
        "anchor": "Equation of state and speed of sound of (2+1)-flavor QCD in\n  strangeness-neutral matter at non-vanishing net baryon-number density: We update results on the QCD equation of state in (2+1)-flavor QCD with\nnon-zero conserved charge chemical potentials obtained from an eighth-order\nTaylor series. We present results for basic bulk thermodynamic observables of\nstrangeness-neutral strong-interaction matter, i.e. pressure, number densities,\nenergy and entropy density, and resum Taylor series results using Pad\\'e\napproximants. Furthermore, we calculate the speed of sound as well as the\nadiabatic compression factor of strangeness-neutral matter on lines of constant\nentropy per net baryon number. We show that the equation of state ($P(n_B),\n\\epsilon (n_B)$) is already well described by the $4^{\\rm th}$-order Taylor\nseries in almost the entire range of temperatures accessible with the beam\nenergy scan in collider mode at the Relativistic Heavy Ion Collider.",
        "positive": "Lattice cut-off effects and their reduction in studies of QCD\n  thermodynamics at non-zero temperature and chemical potential: We clarify the relation between the improvement of dispersion relations in\nthe fermion sector of lattice regularized QCD and the improvement of bulk\nthermodynamic observables. We show that in the infinite temperature limit the\ncut-off dependence in dispersion relations can be eliminated up to O(a^n)\ncorrections, if the quark propagator is chosen to be rotationally invariant up\nto this order. In bulk thermodynamic observables this eliminates cut-off\neffects up to the same order at vanishing as well as non-vanishing chemical\npotential. We furthermore show, that in the infinite temperature, ideal gas\nlimit the dependence of finite cut-off corrections on the chemical potential is\ngiven by Bernoulli polynomials which are universal as they do not depend on a\nparticular discretization scheme. We explicitly calculate leading and\nnext-to-leading order cut-off corrections for some staggered and Wilson fermion\ntype actions and compare these with exact evaluations of the free fermion\npartition functions. This also includes the chirally invariant overlap and\ndomain wall fermion formulations."
    },
    {
        "anchor": "Unquenched QCD with Light Quarks: We present recent results in unquenched lattice QCD with two degenerate light\nsea quarks using the truncated determinant approximation (TDA). In the TDA the\ninfrared modes contributing to the quark determinant are computed exactly up to\nsome cutoff in quark off-shellness (typically 2$\\Lambda_{QCD}$). This approach\nallows simulations to be performed at much lighter quark masses than possible\nwith conventional hybrid MonteCarlo techniques. Results for the static energy\nand topological charge distributions are presented using a large ensemble\ngenerated on very coarse (6$^4$) but physically large lattices. Preliminary\nresults are also reported for the static energy and meson spectrum on 10$^3$x20\nlattices (lattice scale $a^{-1}$=1.15 GeV) at quark masses corresponding to\npions of mass $\\leq$ 200 MeV. Using multiboson simulation to compute the\nultraviolet part of the quark determinant the TDA approach becomes an exact\nwith essentially no increase in computational effort. Some preliminary results\nusing this fully unquenched algorithm are presented.",
        "positive": "Four Flavor Finite Temperature Phase Transition with HYP Action: Where\n  is the First Order Phase Transition Line?: We study the finite temperature phase transition of four flavor staggered\nfermions with hypercubic fat link actions on N_t=4 and N_t=6 temporal lattices.\nOur fat links are constructed with hypercubic blocking (HYP) and therefore are\nvery compact. We present a new algorithm for simulating fermions coupled to HYP\nfat links. The algorithm has a simple form based on the standard overrelaxation\nand heatbath updatings for the pure gauge action. We observe that as we\nincrease the smoothness of the gauge fields by changing the parameters of the\nblocking the very pronounced first order phase transition of the thin link\naction becomes weaker and moves to physically uninteresting values of the gauge\ncoupling. With our smoothest HYP action we do not find any indication of a\nphase transition in the accessible temperature range on the N_t=4 or 6 lattices\neven at quark masses close to the physical light quark mass. We argue that the\nobserved difference in the phase diagram is due to the improved flavor symmetry\nof the smeared link actions."
    },
    {
        "anchor": "Improved renormalization scheme for nonlocal operators: In this paper we present an improved RI-type prescription appropriate for the\nnon-perturbative renormalization of gauge invariant nonlocal operators. In this\nprescription, the non-perturbative vertex function is improved by subtracting\nunwanted finite lattice spacing ($a$) effects, calculated in lattice\nperturbation theory. The method is versatile and can be applied to a wide range\nof fermion and gluon actions, as well as types of nonlocal operators. The\npresence of operator mixing can also be accommodated.\n  Compared to the standard RI' prescription, this variant can be recast as a\nsupplementary finite renormalization, whose coefficients bring about\ncorrections of higher order in $a$; consequently, it coincides with standard\nRI' as $a\\to 0$, however it can afford us a smoother and more controlled\nextrapolation to the continuum limit.\n  In this proof-of-concept calculation we focus on nonlocal fermion bilinear\noperators containing a straight Wilson line. In the numerical implementation we\nuse Wilson/clover fermions and Iwasaki improved gluons. The finite-$a$ terms\nwere calculated to one-loop level in lattice perturbation theory, and to all\norders in $a$, using the same action as the non-perturbative vertex functions.\nWe find that the method leads to significant improvement in the perturbative\nregion indicated by small and intermediate values of the length of the Wilson\nline. This results in a robust extraction of the renormalization functions in\nthat region.\n  We have also applied the above method to operators with stout-smeared links.\nWe show how to perform the perturbative correction for any number of smearing\niterations, and evaluate its effect on the power divergent renormalization\ncoefficients.",
        "positive": "Fourier analysis of the flux-tube distribution in SU(3) lattice QCD: This letter presents a novel analysis of the action/energy density\ndistribution around a static quark-antiquark pair in SU(3) lattice quantum\nchromodynamics. Using the Fourier transformation of the link variable, we\nremove the high-momentum gluon and extract the flux-tube component from the\naction/energy density. When the high-momentum gluon is removed, the statistical\nfluctuation is drastically suppressed, and the singularities from the quark\nself-energy disappear. The obtained flux-tube component is broadly distributed\naround the line connecting the quark and the antiquark."
    },
    {
        "anchor": "Abelian projection in SU(N) gauge theories: The abelian projection in SU(N) gauge theories is discussed in detail, as\nwell as the construction of a disorder parameter to study dual\nsuperconductivity as a mechanism for color confinement. If the ideas of the\nlarge N limit are correct, a universal N-independent behavior is expected for\nthe suitable rescaled disorder parameter as a function of lambda = g^2 N.",
        "positive": "On the stability of Dirac sheet configurations: Using cooling for SU(2) lattice configurations, purely Abelian constant\nmagnetic field configurations were left over after the annihilation of\nconstituents that formed metastable Q=0 configurations. These so-called Dirac\nsheet configurations were found to be stable if emerging from the confined\nphase, close to the deconfinement phase transition, provided their Polyakov\nloop was sufficiently non-trivial. Here we show how this is related to the\nnotion of marginal stability of the appropriate constant magnetic field\nconfigurations. We find a perfect agreement between the analytic prediction for\nthe dependence of stability on the value of the Polyakov loop (the holonomy) in\na finite volume and the numerical results studied on a finite lattice in the\ncontext of the Dirac sheet configurations."
    },
    {
        "anchor": "QCD mesonic screening masses and restoration of chiral symmetry at high\n  T: We present a strategy to study QCD non-perturbatively on the lattice at very\nhigh temperatures. This strategy exploits a non-perturbative, finite-volume,\ndefinition of the strong coupling constant to renormalize the theory. As a\nfirst application we compute the flavor non-singlet mesonic screening masses in\na wide range of temperature, from $T\\sim 1 $ GeV up to $\\sim 160 $ GeV with\nthree flavors in the chiral limit of QCD. Our results show very interesting\nfeatures of the screening spectrum at very high temperatures. On one hand the\nmass splitting between the vector and the pseudoscalar screening masses is\nclearly visible up to the electroweak scale and cannot be explained by the\nknown 1-loop perturbative result. On the other hand the restoration of chiral\nsymmetry manifests itself through the degeneracy of the pseudoscalar and the\nscalar channels and of the vector and the axial-vector ones. This degeneracy\npattern is the one expected by Ward identities associated to the presence of\nchiral symmetry.",
        "positive": "Nearly conformal gauge theories in finite volume: We report new results on nearly conformal gauge theories with fermions in the\nfundamental representation of the SU(3) color gauge group as the number of\nfermion flavors is varied in the Nf = 4-16 range. To unambiguously identify the\nchirally broken phase below the conformal window we apply a comprehensive\nlattice tool set in finite volumes which includes the test of Goldstone pion\ndynamics, the spectrum of the fermion Dirac operator, and eigenvalue\ndistributions of random matrix theory. We also discuss the theory inside the\nconformal window and present our first results on the running of the\nrenormalized gauge coupling and the renormalization group beta function. The\nimportance of understanding finite volume zero momentum gauge field dynamics\ninside the conformal window is illustrated. Staggered lattice fermions are used\nthroughout the calculations."
    },
    {
        "anchor": "Lattice study of the Silver Blaze phenomenon for a charged scalar phi-4\n  field: We analyze a complex scalar field with phi-4 interaction and a chemical\npotential mu on the lattice. An exact flux representation of the partition sum\nis used which avoids the complex action problem and based on a generalized worm\nalgorithm we can run Monte Carlo simulations at arbitrary densities. We study\nthermodynamical quantities as a function of the chemical potential mu for zero-\nand finite temperature. It is shown that at zero temperature thermodynamical\nobservables are independent of mu up to a critical value mu_c (Silver Blaze\nphenomenon). In a spectroscopy calculation we cross-check that mu_c agrees with\nthe mass m of the scalar field. The Silver Blaze region ends in a second order\nphase transition and we show that for low temperatures the second order phase\nboundary persists and separates a pseudo Silver Blaze region from a condensed\nphase with strong mu-dependence.",
        "positive": "No coincidence of center percolation and deconfinement in SU(4) lattice\n  gauge theory: We study the behavior of center sectors in pure SU(4) lattice gauge theory at\nfinite temperature. The center sectors are defined as spatial clusters of\nneighboring sites with values of their local Polyakov loops near the same\ncenter elements. We study the connectedness and percolation properties of the\ncenter clusters across the deconfinement transition. We show that for SU(4)\ngauge theory deconfinement cannot be described as a percolation transition of\ncenter clusters, a finding which is different from pure SU(2) or pure SU(3)\nYang Mills theory, where the percolation description even allows for a\ncontinuum limit."
    },
    {
        "anchor": "SU(3) sextet model with Wilson fermions: We present our final results for the SU(3) sextet model with the non-improved\nWilson fermion discretization. We find evidence for several phases of the\nlattice model, including a bulk phase with broken chiral symmetry. We study the\ntransition between the bulk and weak coupling phase which corresponds to a\nsignificant change in the qualitative behavior of spectral and scale setting\nobservables. In particular the t0 and w0 observables seem to diverge in the\nchiral limit in the weak coupling phase. We then focus on the study of spectral\nobservables in the chiral limit in the weak coupling phase at infinite volume.\nWe consider the masses and decay constants for the pseudoscalar and vector\nmesons, the mass of the axial vector meson and the spin-1/2 baryon as a\nfunction of the quark mass, while controlling finite volume effects. We then\ntest our data against both the IR conformal and the chirally broken hypotheses.",
        "positive": "Finite Temperature Sum Rules in Lattice Gauge Theory: We derive non-perturbative sum rules in SU($N$) lattice gauge theory at\nfinite temperature. They relate the susceptibilities of the trace anomaly and\nenergy-momentum tensor to temperature derivatives of the thermodynamic\npotentials. Two of them have been derived previously in the continuum and one\nis new. In all cases, at finite latttice spacing there are important\ncorrections to the continuum sum rules that are only suppressed by the bare\ncoupling $g_0^2$. We also show how the discretization errors affecting the\nthermodynamic potentials can be controlled by computing these susceptibilities."
    },
    {
        "anchor": "Homotopy, monopoles and 't Hooft tensor for generic gauuge groups: We study monopoles and corresponding 't Hooft tensor in a generic gauge\ntheory. This issue is relevant to the understanding of the color confinement in\nterms of dual symmetry.",
        "positive": "Aharonov-Bohm Effect in Lattice Abelian Higgs Theory: We study a field-theoretical analogue of the Aharonov-Bohm effect in two-,\nthree- and four-dimensional Abelian Higgs models; the corresponding topological\ninteraction is proportional to the linking number of the Abrikosov vortex and\nthe particle world trajectories. We show that the Aharonov-Bohm effect gives\nrise to a nontrivial interaction of charged test particles. The numerical\ncalculations in the three-dimensional model confirm this fact."
    },
    {
        "anchor": "Pion structure from Lattice QCD: We present preliminary study of parton distribution inside the pion using\nmixed action approach with HYP smeared valence clover quarks on HISQ sea within\nthe framework of Large Momentum Effective Theory. We use 2+1 flavor $48^3\n\\times 64$ HISQ lattices with lattices spacing of a=0.06 fm and valence quark\nmasses corresponding to pion mass of 300 MeV.",
        "positive": "The Complex Structure of 2D Surfaces: The complex structure of a surface generated by the two-dimensional dynamical\ntriangulation(DT) is determined by measuring the resistivity of the surface. It\nis found that surfaces coupled to matter fields have well-defined complex\nstructures for cases when the matter central charges are less than or equal to\none, while they become unstable beyond c=1. A natural conjecture that fine\nplanar random network of resistors behave as a continuous sheet of constant\nresistivity is justified numerically for c<1."
    },
    {
        "anchor": "Further lattice evidence for a large re-scaling of the Higgs condensate: Using a high-statistics lattice simulation of the Ising limit of $(\\lambda\n\\Phi^4)_4$ theory, we have measured the susceptibility and propagator in the\nbroken phase. We confirm our earlier finding of a discrepancy between the field\nre-scaling implied by the propagator data and that implied by the\nsusceptibility. The discrepancy becomes {\\it worse} as one goes closer to the\ncontinuum limit; thus, it cannot be explained by residual perturbative effects.\nThe data are consistent with an unconventional description of symmetry breaking\nand ``triviality'' in which the re-scaling factor for the finite-momentum\nfluctuations tends to unity, but the re-scaling factor for the condensate\nbecomes larger and larger as one approaches the continuum limit. In the\nStandard Model this changes the interpretation of the Fermi-constant scale and\nits relation to the Higgs mass.",
        "positive": "Recent Advances in Hamiltonian Lattice Gauge Theory: We review the recent advances in the Hamiltonian formulation of lattice gauge\ntheory for approaching the continuum physics. In particular, vacuum wave\nfunction and glueball spectrum calculations by coupled cluster method with\ntruncation scheme preserving the continuum behavior are described."
    },
    {
        "anchor": "Reconstructing lattice QCD spectral functions with stochastic pole\n  expansion and Nevanlinna analytic continuation: The reconstruction of spectral functions from Euclidean correlation functions\nis a well-known, yet ill-posed inverse problem in the fields of many-body and\nhigh-energy physics. In this paper, we present a comprehensive investigation of\ntwo recently developed analytic continuation methods, namely stochastic pole\nexpansion and Nevanlinna analytic continuation, for extracting spectral\nfunctions from mock lattice QCD data. We examine a range of Euclidean\ncorrelation functions generated by representative models, including the\nBreit-Wigner model, the Gaussian mixture model, the resonance-continuum model,\nand the bottomonium model. Our findings demonstrate that the stochastic pole\nexpansion method, when combined with the constrained sampling algorithm and the\nself-adaptive sampling algorithm, successfully recovers the essential features\nof the spectral functions and exhibits excellent resilience to noise of input\ndata. In contrast, the Nevanlinna analytic continuation method suffers from\nnumerical instability, often resulting in the emergence of spurious peaks and\nsignificant oscillations in the high-energy regions of the spectral functions,\neven with the application of the Hardy basis function optimization algorithm.",
        "positive": "Magnetic polarizability of pion: We explore the energy dependence of $\\pi$ mesons off the background abelian\nmagnetic field on the base of quenched SU(3) lattice gauge theory and calculate\nthe magnetic dipole polarizability of charged and neutral pions for various\nlattice volumes and lattice spacings. The contribution of the magnetic\nhyperpolarizability to the neutral pion energy has been also found."
    },
    {
        "anchor": "Hadron masses from fixed topology simulations: parity partners and SU(2)\n  Yang-Mills results: Lattice QCD simulations tend to get stuck in a single topological sector at\nfine lattice spacing, or when using chirally symmetric quarks. In such cases\ncomputed observables differ from their full QCD counterparts by finite size\neffects, which need to be understood on a quantitative level. We discuss\nextensions of existing relations from the literature between correlation\nfunctions at fixed topology and hadron masses at unfixed topology. Particular\nfocus is put on disentangling positive and negative parity states, which mix,\nwhen the topological charge is fixed. We also present numerical results for\nSU(2) Yang-Mills Theory.",
        "positive": "One-loop renormalization of heavy-light currents: We calculate the mass dependent renormalization factors of heavy-light\nbilinears at one-loop order of perturbation theory, when the heavy quark is\ntreated with the Fermilab formalism.\n  We present numerical results for the Wilson and Sheikholeslami-Wohlert\nactions, with and without tree-level rotation.\n  We find that in both cases our results smoothly interpolate from the static\nlimit to the massless limit.\n  We also calculate the mass dependent Brodsky-Lepage-Mackenzie scale $q^*$,\nwith and without tadpole-improvement."
    },
    {
        "anchor": "Symmetry, Confinement, and the Higgs Phase: We show that the Higgs and confinement phases of a gauge Higgs theory, with\nthe Higgs field in the fundamental representation of the gauge group, are\ndistinguished both by a broken or unbroken realization of the global center\nsubgroup of the gauge group, and by the type of confinement in each phase. This\nis color confinement in the Higgs phase, and a stronger property, which we call\n\"separation-of-charge\" confinement, in the confining phase.",
        "positive": "Topology of two-color QCD at low temperature and high density: The chemical potential ($\\mu$) dependence of the topological susceptibility\nwith two-color two-flavor QCD is studied. We find that at temperature $T\n\\approx T_c /2$, where $T_c$ denotes the critical temperature at zero chemical\npotential, the topological susceptibility is almost constant throughout $0 \\leq\na\\mu \\lesssim 1.0$, while at $T\\approx T_c$, it decreases significantly from\nthe $\\mu=0$ value in a high $\\mu$ regime.\n  In this work, we perform the simulation for $\\mu/T \\le 16$, which covers even\nthe low temperature and the high chemical potential regime. In this regime, we\nintroduce a diquark source term, which is characterized by $j$, into the\naction. We also show our results for the phase diagram in a low temperature\nregime ($T\\approx T_c/2$), which is obtained after taking the $j \\to 0$ limit\nof the diquark condensate and the Polyakov loop."
    },
    {
        "anchor": "Convergent series for polynomial lattice models with complex actions: Lattice models with complex actions are important for the understanding of\nmatter at finite densities, but not accessible by the standard Monte Carlo\ntechniques due to the sign problem. Here we derive a new approach for avoiding\nthe complex action/sign problem, by extending the method of convergent series\nwith a non-Gaussian initial approximation. The main features of the new series\nare demonstrated on the example of the two dimensional oscillating integral.",
        "positive": "S-wave kaon-nucleon potentials with all-to-all propagators in the HAL\n  QCD method: In this paper, employing an all-to-all quark propagator technique, we\ninvestigate the kaon-nucleon interactions in lattice QCD. We calculate the\nS-wave kaon-nucleon potentials at the leading order in the derivative expansion\nin the time-dependent HAL QCD method, using (2+1)-flavor gauge configurations\nat the lattice spacing $a \\approx 0.09$ fm on $32^3 \\times 64$ lattices and the\npion mass $m_{\\pi} \\approx 570$ MeV. We take the one-end trick for all-to-all\npropagators, which allows us to put the zero momentum hadron operators at both\nsource and sink and to smear quark operators at the source. We find the\nstronger repulsive interaction in the $I=1$ channel than in the $I=0$. The\nphase shifts obtained by solving the Schr\\\"{o}dinger equations with the\npotentials qualitatively reproduce the energy dependence of the experimental\nphase shifts, and have the similar behavior to the previous results from\nlattice QCD without all-to-all propagators. Our study demonstrates that the\nall-to-all quark propagator technique with the one-end trick is useful to study\ninteractions for meson-baryon systems in the HAL QCD method, so that we will\napply it to meson-baryon systems which contain quark-antiquark\ncreation/annihilation processes in our future studies."
    },
    {
        "anchor": "Chiral gauge theories on the lattice with exact gauge invariance: A recently proposed formulation of chiral lattice gauge theories is reviewed,\nin which the locality and gauge invariance of the theory can be preserved if\nthe fermion representation of the gauge group is anomaly-free.",
        "positive": "Overlap fermions on GPUs: We report on our efforts to implement overlap fermions on NVIDIA GPUs using\nCUDA, commenting on the algorithms used, implemetation details, and the\nperformance of our code."
    },
    {
        "anchor": "Logarithmic corrections to O($a$) and O($a^2$) effects in lattice QCD\n  with Wilson or Ginsparg-Wilson quarks: We derive the asymptotic lattice spacing dependence\n$a^n[2b_0\\bar{g}^2(1/a)]^{\\hat{\\Gamma}_i}$ relevant for spectral quantities of\nlattice QCD, when using Wilson, O$(a)$ improved Wilson or Ginsparg-Wilson\nquarks. We give some examples for the spectra encountered for $\\hat{\\Gamma}_i$\nincluding the partially quenched case, mixed actions and using two different\ndiscretisations for dynamical quarks. This also includes maximally twisted mass\nQCD relying on automatic O$(a)$ improvement. At O$(a^2)$, all cases considered\nhave $\\min_i\\hat{\\Gamma}_i\\gtrsim -0.3$ if $N_\\mathrm{f}\\leq 4$, which ensures\nthat the leading order lattice artifacts are not severely logarithmically\nenhanced in contrast to the O$(3)$ non-linear sigma model [1,2]. However, we\nfind a very dense spectrum of these leading powers, which may result in major\npile-ups and cancellations. We present in detail the computational strategy\nemployed to obtain the 1-loop anomalous dimensions already used in [3].",
        "positive": "Finite-volume Hamiltonian method for coupled channel interactions in\n  lattice QCD: Within a multi-channel formulation of $\\pi\\pi$ scattering, we investigate the\nuse of the finite-volume Hamiltonian approach to resolve scattering observables\nfrom lattice QCD spectra. The asymptotic matching of the well-known L\\\"uscher\nformalism encodes a unique finite-volume spectrum. Nevertheless, in many\npractical situations, such as coupled-channel systems, it is advantageous to\ninterpolate isolated lattice spectra in order to extract physical scattering\nparameters. Here we study the use of the Hamiltonian framework as a\nparameterisation that can be fit directly to lattice spectra. We find that with\na modest amount of lattice data, the scattering parameters can be reproduced\nrather well, with only a minor degree of model dependence."
    },
    {
        "anchor": "Calculating the I=2 Pion Scattering Length Using Tadpole Improved Clover\n  Wilson Action on Coarse Anisotropic Lattices: In an exploratory study, using the tadpole improved clover Wilson quark\naction on small, coarse and anisotropic lattices, the $\\pi\\pi$ scattering\nlength in the I=2 channel is calculated within quenched approximation. A new\nmethod is proposed which enables us to make chiral extrapolation of our lattice\nresults without calculating the decay constant on the lattice. Finite volume\nand finite lattice spacing errors are analyzed and the results are extrapolated\ntowards the infinite volume and continuum limit. Comparisons of our lattice\nresults with the new experiment and the results from Chiral Perturbation Theory\nare made. Good agreements are found.",
        "positive": "Charm physics with highly improved staggered quarks: We use a relativistic highly improved staggered quark action to discretize\ncharm quarks on the lattice. We calculate the masses and the dispersion\nrelation for heavy-heavy and heavy-light meson states, and show that for\nlattice spacings below .1 fm, the discretization errors are at the few percent\nlevel. We also discuss the prospects for accurate calculations at the few\npercent level of f_D_s, f_D, and the leptonic width of the psi and phi."
    },
    {
        "anchor": "The 2+1 flavor topological susceptibility from the asqtad action at 0.06\n  fm: We report new data for the topological susceptibility computed on 2+1 flavor\ndynamical configurations with lattice spacing 0.06 fm, generated with the\nasqtad action. The topological susceptibility is computed by HYP smearing and\ncompared with rooted staggered chiral perturbation theory as the pion mass goes\nto zero. At 0.06 fm, the raw data is already quite close to the continuum\nextrapolated values obtained from coarser lattices. These results provide a\nfurther test of the asqtad action with rooted staggered flavors.",
        "positive": "Color confinement and dual superconductivity in unquenched QCD: We report on evidence from lattice simulations that confinement is produced\nby dual superconductivity of the vacuum in full QCD as in quenched QCD.\nPreliminary information is obtained on the order of the deconfining phase\ntransition."
    },
    {
        "anchor": "Two-Loop Fermionic Integrals in Perturbation Theory on a Lattice: A comprehensive number of one-loop integrals in a theory with Wilson fermions\nat $r=1$ is computed using the Burgio-Caracciolo-Pelissetto algorithm. With the\nuse of these results, the fermionic propagator in the coordinate representation\nis evaluated, thus making it possible to extend the Luscher-Weisz procedure for\ntwo-loop integrals to the fermionic case. Computations are performed with FORM\nand REDUCE packages.",
        "positive": "Nonperturbative Renormalization in Lattice QCD with three Flavors of\n  Clover Fermions: Using Periodic and Open Boundary Conditions: We present the nonperturbative computation of renormalization factors in the\nRI'-(S)MOM schemes for the QCD gauge field ensembles generated by the CLS\n(coordinated lattice simulations) effort with three flavors of\nnonperturbatively improved Wilson (clover) quarks. We use ensembles with the\nstandard (anti-)periodic boundary conditions in the time direction as well as\ngauge field configurations with open boundary conditions. Besides\nflavor-nonsinglet quark-antiquark operators with up to two derivatives we also\nconsider three-quark operators with up to one derivative. For the RI'-SMOM\nscheme results we make use of the recently calculated three-loop conversion\nfactors to the modified minimal subtraction scheme. The present version of the\npaper contains an Addendum with additional analytical expressions and updated\nresults."
    },
    {
        "anchor": "Properties of near-zero modes and chiral symmetry breaking: We study localization and chirality properties of eigenvectors of the lattice\nDirac operator. In particular we focus on the dependence of our observables on\nthe size of the corresponding eigenvalue, which allows us to study the\ntransition of a near-zero mode into a bulk mode. We analyze ensembles of\nquenched SU(3) configurations using a Dirac operator which is a systematic\nexpansion in path length of a solution of the Ginsparg-Wilson equation. Our\nresults support the interpretation of the excitations relevant for chiral\nsymmetry breaking as interacting instantons and anti-instantons.",
        "positive": "Linear systems solvers - recent developments and implications for\n  lattice computations: We review the numerical analysis' understanding of Krylov subspace methods\nfor solving (non-hermitian) systems of equations and discuss its implications\nfor lattice gauge theory computations using the example of the Wilson fermion\nmatrix. Our thesis is that mature methods like QMR, BiCGStab or restarted GMRES\nare close to optimal for the Wilson fermion matrix. Consequently,\npreconditioning appears to be the crucial issue for further improvements."
    },
    {
        "anchor": "Finite Volume Corrections to the SU(3) Deconfining Temperature due to a\n  Confined Exterior: Deconfined regions in relativistic heavy ion collisions are limited to small\nvolumes surrounded by a confined exterior. Using the geometry of a double\nlayered torus, we keep an outside temperature slightly lower than the inside\ntemperature, so that both regions are in the SU(3) scaling region. Deconfined\nvolume sizes are chosen to be in a range typical for such volumes created at\nthe BNL RHIC. Even with small temperature differences a dependence of the\n(pseudo) deconfining temperature on a colder surrounding temperature is clearly\nvisible. For temporal lattice sizes Ntau=4, 6 and 8 we find consistency with\nSU(3) scaling behavior for the measured transition temperature signals.",
        "positive": "Flavour Breaking Effects of Wilson twisted mass fermions: We study the flavour breaking effects appearing in the Wilson twisted mass\nformulation of lattice QCD. In this quenched study, we focus on the mass\nsplitting between the neutral and the charged pion, determining the neutral\npion mass with a stochastic noise method to evaluate the disconnected\ncontributions. We find that these disconnected contributions are significant.\nUsing the Osterwalder-Seiler interpretation of the connected piece of the\nneutral pion correlator, we compute the corresponding neutral pion mass to\nstudy with more precision the scaling behaviour of the mass splitting."
    },
    {
        "anchor": "Unquenched Charmonium with NRQCD: We present the results from a series of lattice simulations of the charmonium\nsystem using a highly-improved NRQCD action, both in the quenched\napproximation, and with n_f = 2 light dynamical quarks. The spectra show some\nevidence for quenching effects of roughly 10% in the S- and P-hyperfine spin\nsplittings---probably too small to account for the severe underestimates in\nthese quantities seen in previous quenched charmonium simulations. We also find\nestimates for the magnitude of other systematic effects---in particular, the\nchoice of the tadpole factor can alter spin splittings at the 10-20% level, and\nradiative corrections may be as large as 40% for charmonium. We conclude that\nquenching is just one of a collection of important effects that require\nattention in precision heavy-quark simulations.",
        "positive": "Status of ETMC simulations with Nf=2+1+1 twisted mass fermions: We present the status of runs performed in the twisted mass formalism with\n$N_{\\rm f}=2+1+1$ flavours of dynamical fermions: a degenerate light doublet\nand a mass split heavy doublet. The procedure for tuning to maximal twist will\nbe described as well as the current status of the runs using both thin and\nstout links. Preliminary results for a few observables obtained on ensembles at\nmaximal twist will be given. Finally, a reweighting procedure to tune to\nmaximal twist will be described."
    },
    {
        "anchor": "Quark-gluon vertex in a momentum subtraction scheme: We compute the quark-gluon vertex in quenched QCD, in the Landau gauge using\nan off-shell mean-field O(a)-improved fermion action. The running coupling is\ncalculated in an `asymmetric' momentum subtraction scheme (MOM~). We obtain a\ncrude estimate for Lambda_MSbar=170+/-65 MeV, which is considerably lower than\nother determinations of this quantity. However, substantial systematic errors\nremain.",
        "positive": "Dirac zero-modes in compact U(1) gauge theory: We study properties of the zero and near-zero eigenmodes of the overlap Dirac\noperator in compact U(1) gauge theory. In the confinement phase the exact\nzero-modes are localized as found by studying the values of the inverse\nparticipation ratio and other features. Non-zero-eigenmodes are less localized\nin the confinement phase. In the Coulomb phase no zero-modes are observed and\nthe eigenmodes show no localization at all."
    },
    {
        "anchor": "Relative weights approach to SU(3) gauge theories with dynamical\n  fermions at finite density: We derive effective Polyakov line actions for SU(3) gauge theories with\nstaggered dynamical fermions, for a small sample of lattice couplings, lattice\nactions, and lattice extensions in the time direction. The derivation is via\nthe method of relative weights, and the theories are solved at finite chemical\npotential by mean field theory. We find in some instances that the long-range\ncouplings in the effective action are very important to the phase structure,\nand that these couplings are responsible for long-lived metastable states in\nthe effective theory. Only one of these states corresponds to the underlying\nlattice gauge theory.",
        "positive": "Exact blocking formulas for spin and gauge models: Using the example of the two-dimensional (2D) Ising model, we show that in\ncontrast to what can be done in configuration space, the tensor renormalization\ngroup (TRG) formulation allows one to write exact, compact, and manifestly\nlocal blocking formulas and exact coarse grained expressions for the partition\nfunction. We argue that similar results should hold for most models studied by\nlattice gauge theorists. We provide exact blocking formulas for several 2D spin\nmodels (the O(2) and O(3) sigma models and the SU(2) principal chiral model)\nand for the 3D gauge theories with groups Z_2, U(1) and SU(2). We briefly\ndiscuss generalizations to other groups, higher dimensions and practical\nimplementations."
    },
    {
        "anchor": "Efficient Hadronic Operators in Lattice Gauge Theory: We propose the study of non-local gauge invariant operators to obtain an\nuncontaminated ground state for hadrons. The efficiency of the operators is\nshown by looking at the wave function of the first excited state, which has a\nnode as a function of spatial extent of the operator.",
        "positive": "Conformal dimensions via large charge expansion: We construct an efficient Monte Carlo algorithm that overcomes the severe\nsignal-to-noise ratio problems and helps us to accurately compute the conformal\ndimensions of large-$Q$ fields at the Wilson-Fisher fixed point in the $O(2)$\nuniversality class. Using it we verify a recent proposal that conformal\ndimensions of strongly coupled conformal field theories with a global $U(1)$\ncharge can be obtained via a series expansion in the inverse charge $1/Q$. We\nfind that the conformal dimensions of the lowest operator with a fixed charge\n$Q$ are almost entirely determined by the first few terms in the series."
    },
    {
        "anchor": "Emergent Structure in QCD: The structure of the SU(3) gauge-field vacuum is explored through\nvisualisations of centre vortices and topological charge density. Stereoscopic\nvisualisations highlight interesting features of the vortex vacuum, especially\nthe frequency with which singular points appear and the important connection\nbetween branching points and topological charge. This work demonstrates how\nvisualisations of the QCD ground-state fields can reveal new perspectives of\ncentre-vortex structure.",
        "positive": "An improved algorithm for dynamical triangulations and simulations of\n  finer lattices: We introduce a new algorithm for the simulation of Euclidean dynamical\ntriangulations that mimics the Metropolis-Hastings algorithm, but where all\nproposed moves are accepted. This rejection-free algorithm allows for the\nfactorization of local and global terms in the action, a condition needed for\nefficient simulation of theories with global terms, while still maintaining\ndetailed balance. We test our algorithm on the $2d$ Ising model, and against\nresults for EDT obtained with standard Metropolis. Our new algorithm allows us\nto simulate EDT at finer lattice spacings than previously possible, and we find\ngeometries that resemble semiclassical Euclidean de Sitter space in agreement\nwith earlier results at coarser lattices. The agreement between lattice data\nand the classical de Sitter solution continues to get better as the lattice\nspacing decreases."
    },
    {
        "anchor": "Calculation of the hadronic vacuum polarization contribution to the muon\n  anomalous magnetic moment: We present a first-principles lattice QCD+QED calculation at physical pion\nmass of the leading-order hadronic vacuum polarization contribution to the muon\nanomalous magnetic moment. The total contribution of up, down, strange, and\ncharm quarks including QED and strong isospin breaking effects is found to be\n$a_\\mu^{\\rm HVP~LO}=715.4(16.3)(9.2) \\times 10^{-10}$, where the first error is\nstatistical and the second is systematic. By supplementing lattice data for\nvery short and long distances with experimental R-ratio data using the\ncompilation of Ref. [1], we significantly improve the precision of our\ncalculation and find $a_\\mu^{\\rm HVP~LO} = 692.5(1.4)(0.5)(0.7)(2.1) \\times\n10^{-10}$ with lattice statistical, lattice systematic, R-ratio statistical,\nand R-ratio systematic errors given separately. This is the currently most\nprecise determination of the leading-order hadronic vacuum polarization\ncontribution to the muon anomalous magnetic moment. In addition, we present the\nfirst lattice calculation of the light-quark QED correction at physical pion\nmass.",
        "positive": "Finite Volume Effects in Weak Hadronic Decays: In this talk we discuss finite-volume computations of two-body hadronic\ndecays below the inelastic threshold (e.g. $K\\to\\pi\\pi$ decays). In particular\nwe show how the relation between finite-volume matrix elements and physical\namplitudes, recently derived by Lellouch and L\\\"uscher, can be extended to all\nelastic states under the inelastic threshold. We also provide a derivation of\nthe L\\\"uscher quantization condition directly in quantum field theory."
    },
    {
        "anchor": "Vacuum expectation value of A^2 from LQCD: We argue from LQCD that there is a non vanishing v.e.v of $A_a^\\mu A^a_\\mu$\nin QCD in the Landau gauge. We use operator product expansion to provide a\nclear definition of $A_a^\\mu A^a_\\mu$ and extract a number both in the quenched\nand unquenched case.",
        "positive": "Deep inelastic scattering off quark-gluon plasma and its photon\n  emissivity: The photon emissivity of quark-gluon plasma probes the interactions in the\nmedium and differs qualitatively between a weakly coupled and a strongly\ncoupled plasma in the soft-photon regime. The photon emissivity is given by the\nproduct of kinematic factors and a spectral function associated with the\ntwo-point correlator of the electromagnetic current at lightlike kinematics. A\ncertain Euclidean correlator at imaginary spatial momentum can be calculated in\nlattice QCD and is given by an integral over the relevant spectral function at\nlightlike kinematics. I present a first exploratory lattice calculation of this\ncorrelator. Secondly, I show how Euclidean correlators at imaginary spatial\nmomenta can also be used to probe the regime of deep inelastic scattering off\nquark-gluon plasma, which reveals its parton distribution function."
    },
    {
        "anchor": "3-body quantization condition in a unitary formalism: Unitarity identifies all power-law finite-volume effects and is, therefore,\nthe crucial S-matrix principle for a mapping between experimental results and\nthose of Lattice QCD calculations. In this contribution we review how 3-body\nunitarity constrains the form of the 3-body scattering amplitude parametrized\nby the tower of isobars. The result is discretized and projected to the\nirreducible representations of the cubic group, leading to a fully relativistic\n3-body quantization condition. The latter is used to deduce the finite-volume\nexcited level spectrum of the $\\pi^+\\pi^+\\pi^+$ system, which agrees nicely\nwith the available lattice results by the NPLQCD collaboration.",
        "positive": "Geometrical aspects of lattice gauge equivariant convolutional neural\n  networks: Lattice gauge equivariant convolutional neural networks (L-CNNs) are a\nframework for convolutional neural networks that can be applied to non-Abelian\nlattice gauge theories without violating gauge symmetry. We demonstrate how\nL-CNNs can be equipped with global group equivariance. This allows us to extend\nthe formulation to be equivariant not just under translations but under global\nlattice symmetries such as rotations and reflections. Additionally, we provide\na geometric formulation of L-CNNs and show how convolutions in L-CNNs arise as\na special case of gauge equivariant neural networks on SU($N$) principal\nbundles."
    },
    {
        "anchor": "Polyakov loop in different representations of SU(3) at finite\n  temperature: We investigate the Polyakov loop in different representations of SU(3) in\npure gauge at finite $T$. We discuss Casimir scaling for the Polyakov loop in\nthe deconfined phase and test and generalize the renormalization procedure for\nthe Polyakov loop from \\cite{Kaczmarek:2002mc} to arbitrary representations. In\nthe confined phase we extract the renormalized adjoint Polyakov loop, which is\nfinite in the thermodynamic limit. For our numerical calculations we used the\ntree-level improved Symanzik action on $32^3\\times 4,6,8$ lattices.",
        "positive": "Scaling of Nonperturbative Renormalization of Composite Operators with\n  Overlap Fermions: We compute non-perturbatively the renormalization constants of composite\noperators for overlap fermions by using the regularization independent scheme.\nThe scaling behavior of the renormalization constants is investigated using the\ndata from three lattices with similar physical volumes and different lattice\nspacings. The approach of the renormalization constants to the continuum limit\nis explored."
    },
    {
        "anchor": "SU(2) meets SU(3) in lattice-Landau-gauge gluon and ghost propagators: A comparative study of the lattice Landau gauge gluon and ghost propagators\nfor SU(2) and SU(3) pure Yang-Mills theories is carried out. The data were\nspecially produced with equivalent lattice parameters to allow for a careful\ncomparison of the two cases. We find very good agreement between the two\ntheories. Our results seem to confirm the predicton of Schwinger-Dyson\nequations that the infrared exponents are independent of the gauge group SU(N).",
        "positive": "Critical behavior of lattice Schwinger model with topological term at\n  $\u03b8=\u03c0$ using Grassmann tensor renormalization group: Lattice regularized Schwinger model with a so-called $\\theta$ term is studied\nby using the Grassmann tensor renormalization group. We perform the Lee-Yang\nand Fisher zero analyses in order to investigate the phase structure at\n$\\theta=\\pi$. We find a first order phase transition at larger fermion mass.\nBoth of the Lee-Yang zero and Fisher zero analyses indicate that the critical\nendpoint at which the first order phase transition terminates belongs to the\nIsing universality class."
    },
    {
        "anchor": "Non-perturbative renormalization in lattice QCD: In this talk I will discuss a number of approaches designed to deal with the\nproblem of setting up a fully non-perturbative renormalization procedure in\nlattice QCD. Methods based on Ward-Takahashi identities on hadronic states, on\nimposing chiral selection rules on amplitudes with external quark/gluon legs,\non the use of the Schr\\\"{o}dinger functional and on ``heating and cooling''\nMonte Carlo steps are reviewed. I conclude with some remarks on the possibility\nof defining next order terms (higher twists, ``condensates\", ...) in short\ndistance expansions.",
        "positive": "A strategy for B-physics observables in the continuum limit: In a somewhat forgotten paper [1] it was shown how to perform interpolations\nbetween relativistic and static computations in order to obtain results for\nheavy-light observables for masses from, say, $m_{\\rm charm}$ to $m_{\\rm\nbottom}$. All quantities are first continuum extrapolated and then interpolated\nin $1/m_h=1/m_{\\rm heavy}$. Large volume computations are combined with finite\nvolume ones where a relativistic bottom quark is accessible with small $am_{\\rm\nbottom}$. We discuss how this strategy is extended to semi-leptonic form\nfactors and other quantities of phenomenological interest. The essential point\nis to form quantities where the limit $m_h\\to\\infty$ is approached with power\ncorrections O$(1/m_h)$ only. Perturbative corrections\n$\\sim\\alpha_s(m_h)^{\\gamma+n}$ are cancelled in the construction of the\nobservables. We also point out how such an approach can help to control\nsystematics in semi-leptonic decays with just large volume data. First\nnumerical results with $N_f = 2 + 1$ and lattice spacings down to 0.039 fm are\npresented in [2]."
    },
    {
        "anchor": "Zero modes of Overlap fermions, instantons, and monopoles: The purpose of this study is to investigate the relations between instantons,\nmonopoles, and Chiral symmetry breaking. The monopoles are important\ntopological configurations existing in QCD which are believed to produce colour\nconfinement. The groups of University of Kanazawa and Pisa have produced by\nLattice simulations many results supporting the idea that QCD vacuum is a dual\nsuperconductor. Instantons are related to Chiral symmetry breaking, as\nexplained e.g. in the instanton liquid model of E. V. SHURYAK. Clarifying\nquantitatively the relation between monopoles and instantons is not easy, also\nbecause monopoles are three dimensional objects, while instantons are four\ndimensional. We generate configurations, adding monopole-antimonopole pairs of\nopposite charges by a monopole creation operator. We observe that the monopole\ncreation operator only adds long monopole loops in the configurations. Then, we\ncount the number of fermion zero modes in the configurations using Overlap\nfermions as a tool. Finally, we find that one monopole-antimonopole pair makes\none zero mode of plus or minus chirality, that is to say, one instanton of plus\nor minus charge.",
        "positive": "Towards meaningful physics from generative models: In several physical systems, important properties characterizing the system\nitself are theoretically related with specific degrees of freedom. Although\nstandard Monte Carlo simulations provide an effective tool to accurately\nreconstruct the physical configurations of the system, they are unable to\nisolate the different contributions corresponding to different degrees of\nfreedom. Here we show that unsupervised deep learning can become a valid\nsupport to MC simulation, coupling useful insights in the phases detection task\nwith good reconstruction performance. As a testbed we consider the 2D XY model,\nshowing that a deep neural network based on variational autoencoders can detect\nthe continuous Kosterlitz-Thouless (KT) transitions, and that, if endowed with\nthe appropriate constrains, they generate configurations with meaningful\nphysical content."
    },
    {
        "anchor": "Temporal mesonic correlators at NLO for any quark mass: We present NLO results for thermal imaginary-time correlators in the vector\nand scalar channels as a function of the quark mass. The range of quark masses\nfor which a non-relativistic approximation works in the temperature range\nconsidered is estimated, and charm quarks turn out to be a borderline case.\nComparing with simulation data from fine lattices, we find good agreement in\nthe vector channel but a substantial discrepancy in the scalar one. An\nexplanation for the discrepancy is suggested in terms of physics of the\nquark-antiquark threshold region. Perturbative predictions for the bottom\nscalar spectral function around the threshold are also briefly reviewed.",
        "positive": "Monte Carlo simulations on Graphics Processing Units: Implementation of basic local Monte-Carlo algorithms on ATI Graphics\nProcessing Units (GPU) is investigated. The Ising model and pure SU(2)\ngluodynamics simulations are realized with the Compute Abstraction Layer (CAL)\nof ATI Stream environment using the Metropolis and the heat-bath algorithms,\nrespectively. We present an analysis of both CAL programming model and the\nefficiency of the corresponding simulation algorithms on GPU. In particular,\nthe significant performance speed-up of these algorithms in comparison with\nserial execution is observed."
    },
    {
        "anchor": "Numerical study of QCD phase diagram at high temperature and density by\n  a histogram method: We study the QCD phase structure at high temperature and density adopting a\nhistogram method. Because the quark determinant is complex at finite density,\nthe Monte-Carlo method cannot be applied directly. We use a reweighting method\nand try to solve the problems which arise in the reweighting method, i.e. the\nsign problem and the overlap problem. We discuss the chemical potential\ndependence of the probability distribution function in the heavy quark mass\nregion and examine the applicability of the approach in the light quark region.",
        "positive": "Broadening of the confining flux tube joining higher-representation\n  sources: In the context of confining gauge theories we study the flux tube generated\nby a pair of static sources belonging to higher rank representations of the\ngauge group. Using a simple geometric approach based on minimal surfaces\ndescribing the world-sheet of the underlying k-string, we infer logarithmic\nbroadening of the flux tube as a function of source separation. It turns out\nthat the coefficient of the logarithm does not depend on the specific\nrepresentation of the source nor on its N-ality and is universal. Numerical\nresults on a Z_4 gauge theory in three dimensions with static sources carrying\ntwo units of elementary flux compare very favourably with these predictions."
    },
    {
        "anchor": "3d physics and the electroweak phase transition: a framework for lattice\n  Monte Carlo analysis: We discuss a framework relying on both perturbative and non-perturbative\nlattice computations which will be able to reliably determine the parameters of\nthe EW phase transition. A motivation for the use of 3d effective theory in the\nlattice simulations, rather than the complete 4d one, is provided. We introduce\nand compute on the 2-loop level a number of gauge-invariant order parameters --\ncondensates, which can be measured with high accuracy in MC simulations. The\nrelation between MSbar and lattice condensates is found, together with the\nrelation between lattice couplings and continuum parameters (the constant\nphysics curves). These relations are exact in the continuum limit.",
        "positive": "Lattice QCD with open boundary conditions and twisted-mass reweighting: Lattice QCD simulations at small lattice spacings and quark masses close to\ntheir physical values are technically challenging. In particular, the\nsimulations can get trapped in the topological charge sectors of field space or\nmay run into instabilities triggered by accidental near-zero modes of the\nlattice Dirac operator. As already noted in ref. [1], the first problem is\nbypassed if open boundary conditions are imposed in the time direction, while\nthe second can potentially be overcome through twisted-mass determinant\nreweighting [2]. In this paper, we show that twisted-mass reweighting works out\nas expected in QCD with open boundary conditions and 2+1 flavours of O(a)\nimproved Wilson quarks. Further algorithmic improvements are tested as well and\na few physical quantities are computed for illustration."
    },
    {
        "anchor": "Nucleon Magnetic Moments Beyond the Perturbative Chiral Regime: The quark mass dependence of nucleon magnetic moments is explored over a wide\nrange. Quark masses currently accessible to lattice QCD, which lie beyond the\nregime of chiral perturbation theory (chiPT), are accessed via the cloudy bag\nmodel (CBM). The latter reproduces the leading nonanalytic behavior of chiPT,\nwhile modeling the internal structure of the hadron under investigation. We\nfind that the predictions of the CBM are succinctly described by the simple\nformula, \\mu_N(m_\\pi) = \\mu^{(0)}_N / (1 + \\alpha m_\\pi + \\beta m_\\pi^2), which\nreproduces the lattice data, as well as the leading nonanalytic behavior of\nchiPT. As this form also incorporates the anticipated Dirac moment behavior in\nthe limit m_\\pi \\to \\infty, it constitutes a powerful method for extrapolating\nlattice results to the physical mass regime.",
        "positive": "Equation of state for cold and dense heavy QCD: A previously derived three-dimensional effective lattice theory describing\nthe thermodynamics of QCD with heavy quarks in the cold and dense region is\nextended through order $\\sim u^5\\kappa^8$ in the combined character and hopping\nexpansion of the original four-dimensional Wilson action. The systematics of\nthe effective theory is investigated to determine its range of validity in\nparameter space. We demonstrate the severe cut-off effects due to lattice\nsaturation, which afflict any lattice results at finite baryon density\nindependent of the sign problem or the quality of effective theories, and which\nhave to be removed by continuum extrapolation. We then show how the effective\ntheory can be solved analytically by means of a linked cluster expansion, which\nis completely unaffected by the sign problem, in quantitative agreement with\nnumerical simulations. As an application, we compute the cold nuclear equation\nof state of heavy QCD. Our continuum extrapolated result is consistent with a\npolytropic equation of state for non-relativistic fermions."
    },
    {
        "anchor": "Hyperon-nucleon potentials from lattice QCD: We calculate $p\\Xi^0$ potentials from the equal-time Bethe-Salpeter amplitude\nmeasured in the quenched QCD simulation with the spatial lattice volume, (4.4\nfm)$^3$. The standard Wilson gauge action with the gauge coupling $\\beta=5.7$\non $32^4$ lattice together with the standard Wilson quark action are used. The\nhopping parameter $\\kappa_{ud}=0.1678$ is chosen for $u$ and $d$ quarks, which\ncorresponds to $m_{\\pi}\\simeq 0.37$ GeV. The physical strange quark mass is\nused by taking the parameter $\\kappa_s=0.1643$ which is deduced from the\nphysical $K$ meson mass. The lattice spacing $a=0.1420$ fm is determined by the\nphysical $\\rho$ meson mass. We find that the $p\\Xi^0$ potential has strong spin\ndependence. Strong repulsive core is found in $^1S_0$ channel while the\neffective central potential in the $^3S_1$ channel has relatively weak\nrepulsive core. The potentials also have weak attractive parts in the medium to\nlong distance region (0.6 fm $\\lsim r \\lsim 1.2$ fm) in both of the $^1S_0$ and\n$^3S_1$ channels.",
        "positive": "Idealized Multigrid Algorithm for Staggered Fermions: An idealized multigrid algorithm for the computation of propagators of\nstaggered fermions is investigated.\n  Exemplified in four-dimensional $SU(2)$ gauge fields, it is shown that the\nidealized algorithm preserves criticality under coarsening.\n  The same is not true when the coarse grid operator is defined by the Galerkin\nprescription.\n  Relaxation times in computations of propagators are small, and critical\nslowing is strongly reduced (or eliminated) in the idealized algorithm.\n  Unfortunately, this algorithm is not practical for production runs, but the\ninvestigations presented here answer important questions of principle."
    },
    {
        "anchor": "Baryons in the Gross-Neveu model in 1+1 dimensions at finite number of\n  flavors: In a recent work we studied the phase structure of the Gross-Neveu (GN) model\nin $1+1$ dimensions at finite number of fermion flavors $N_\\mathrm{f} = 2, 8,\n16$, finite temperature and finite chemical potential using lattice field\ntheory. Most importantly, we found an inhomogeneous phase at low temperature\nand large chemical potential, quite similar to the analytically solvable\n$N_\\mathrm{f} \\rightarrow \\infty$ limit. In the present work we continue our\nlattice field theory investigation of the finite-$N_\\mathrm{f}$ GN model by\nstudying the formation of baryons, their spatial distribution and their\nrelation to the chiral condensate. As a preparatory step we also discuss a\nlinear coupling of lattice fermions to the chemical potential.",
        "positive": "Critical behaviors as functions of the bare-mass: In Ising model on the simple cubic lattice, we describe the inverse\ntemperature \\beta in terms of the bare-mass M and study its critical behavior\nby the use of delta expansion from high temperature or large M side. In the\nvicinity of critical temperature \\beta_{c}, the expansion of \\beta in M has\n\\beta_{c} as the first term and M^{-1/2\\nu} as the leading correction. The\nestimation of \\beta_{c} in 1/M expansion is confronted with the leading and\nhigher order corrections, even delta expansion is applied and the critical\nregion emerges. To improve the estimation status of \\beta_{c}, we try to\nsuppress the corrections by adding derivatives of \\beta(M) with free adjustable\nparameters. By optimizing the parameters with the help of the principle of\nminimum sensitivity which are maximally imposed in accord with the number of\nparameters, estimation of \\beta_{c} is carried out and the result is found to\nbe in good agreement with the present world average. In the same time, the\ncritical exponent {\\nu} is also estimated."
    },
    {
        "anchor": "Non-Perturbative Improvement of the Anisotropic Wilson QCD Action: We describe the first steps in the extension of the Symanzik O($a$)\nimprovement program for Wilson-type quark actions to anisotropic lattices, with\na temporal lattice spacing smaller than the spatial one. This provides a fully\nrelativistic and computationally efficient framework for the study of heavy\nquarks. We illustrate our method with accurate results for the quenched\ncharmonium spectrum.",
        "positive": "Investigating Yang-Mills theory and Confinement as a function of the\n  spatial volume: We study the volume dependence of electric flux energies for SU(2) gauge\ntheory with twisted boundary conditions. The curves interpolate smoothly\nbetween the perturbative semiclassicalresults and the Confinement regime. On\nthe basis of our results, we propose that the Confinement property might be\ncaused by a class of non-dilute multi-instanton configurations."
    },
    {
        "anchor": "Chemical potential on the lattice: Universal or Unique?: Lattice techniques are the most reliable ones to investigate non-perturbative\naspects of quantum chromodynamics (QCD) such as its phase diagram in the\ntemperature-baryon density plane. They are, however, well-known to be beset\nwith a variety of problems as one increases the density. We address here the\nold question of placing the baryonic (quark) chemical potential on the lattice.\nWe point out that it may have important consequences for the current and future\nexperimental searches of QCD critical point.",
        "positive": "Finite Density Results for Wilson Fermions Using the Volume Method: Nonzero chemical potential studies with Wilson fermions should avoid the\nproliferation of flavor-equivalent nucleon states encountered with staggered\nformulation of fermions. However, conventional wisdom has been that finite\nbaryon density calculations with Wilson fermions will be prohibitively\nexpensive. We demonstrate that the volume method applied to Wilson fermions\ngives surprisingly stable results on a small number of configurations. It is\npointed out that this method may be applied to any local or nonlocal gauge\ninvariant quantity. Some illustrative results for $<\\overline{\\psi}\\psi>$ and\n$< J >$ at various values of $\\mu$ in a quenched lattice simulation are given."
    },
    {
        "anchor": "Phase structure of the 1+1 dimensional massive Thirring model from\n  matrix product states: Employing matrix product states as an ansatz, we study the non-thermal phase\nstructure of the (1+1)-dimensional massive Thirring model in the sector of\nvanishing total fermion number with staggered regularization. In this paper,\ndetails of the implementation for this project are described. To depict the\nphase diagram of the model, we examine the entanglement entropy, the fermion\nbilinear condensate and two types of correlation functions. Our investigation\nshows the existence of two phases, with one of them being critical and the\nother gapped. An interesting feature of the phase structure is that the theory\nwith non-zero fermion mass can be conformal. We also find clear numerical\nevidence that these phases are separated by a transition of the\nBerezinskii-Kosterlitz-Thouless type. Results presented in this paper establish\nthe possibility of using the matrix product states for probing this type of\nphase transition in quantum field theories. They can provide information for\nfurther exploration of scaling behaviour, and serve as an important ingredient\nfor controlling the continuum extrapolation of the model.",
        "positive": "Nuclear Physics: Lattice QCD is making good progress toward calculating the structure and\nproperties of light nuclei and the forces between nucleons. These calculations\nwill ultimately refine the nuclear forces, particularly in the three- and\nfour-nucleon sector and the short-distance interactions of nucleons with\nelectroweak currents, and allow for a reduction of uncertainties in nuclear\nmany-body calculations of nuclei and their reactions. After highlighting their\nimportance, particularly to the Nuclear Physics and High-Energy Physics\nexperimental programs, I discuss the progress that has been made toward\nachieving these goals and the challenges that remain."
    },
    {
        "anchor": "Aspects of QCD Vacuum Structure: The impact of dynamical fermions on the vacuum structure of QCD is explored.\nOf particular interest is the topological charge correlator, $<q(x) q(0) >$,\nwhere negative values at small $x$ reveal a sign-alternating layered structure\nto the topological-charge density of the QCD vacuum. We consider large $28^3\n\\times 96$ lattices from the MILC collaboration, and develop a new gluonic\ndefinition of the topological charge density, founded on a new over-improved\nstout-link smearing algorithm. The algorithm reproduces established results\nfrom the overlap formalism and is designed to preserve instantons. We examine\nthe extent to which instanton-like objects are found on the lattice. Finally,\nwe investigate the effects of dynamical sea-quark degrees of freedom on\ntopology and find that the magnitudes of the negative dip in the $<q(x)q(0)>$\ncorrelator and the positive $<q(0)^2>$ contact term are both increased with the\nintroduction of dynamical fermion degrees of freedom. This is in accord with\nexpectations based on charge renormalization and the vanishing of the\ntopological susceptibility in the chiral limit.",
        "positive": "A simple approach towards the sign problem using path optimisation: We suggest an approach for simulating theories with a sign problem that\nrelies on optimisation of complex integration contours that are not restricted\nto lie along Lefschetz thimbles. To that end we consider the toy model of a\none-dimensional Bose gas with chemical potential. We identify the main\ncontribution to the sign problem in this case as coming from a nearest\nneighbour interaction and approximately cancel it by an explicit deformation of\nthe integration contour. We extend the obtained expressions to more general\nones, depending on a small set of parameters. We find the optimal values of\nthese parameters on a small lattice and study their range of validity. We also\nidentify precursors for the onset of the sign problem. A fast method of\nevaluating the Jacobian related to the contour deformation is proposed and its\nnumerical stability is examined. For a particular choice of lattice parameters,\nwe find that our approach increases the lattice size at which the sign problem\nbecomes serious from $L \\approx 32$ to $L \\approx 700$. The efficient\nevaluation of the Jacobian ($O(L)$ for a sweep) results in running times that\nare of the order of a few minutes on a standard laptop."
    },
    {
        "anchor": "SU(3) Flavor Breaking in Hadronic Matrix Elements for $B - \\bar B$\n  Oscillations: Results in the quenched approximation for SU(3) breaking ratios of the\nheavy-light decay constants and the $\\Delta F=2$ mixing matrix elements are\nreported. Using lattice simulations at $6/g^2=5.7$, 5.85, 6.0, and 6.3, we\ndirectly compute the mixing matrix element $M_{hl}=< \\bar P_{hl}|\\bar h\n\\gamma_\\mu (1-\\gamma_5)l \\bar h \\gamma_\\mu(1-\\gamma_5)l|P_{hl}>$. Extrapolating\nto the physical B meson states, $B^0$ and $B_s^0$, we obtain $M_{bs}/M_{bd}\n=1.76(10)^{+57}_{-42}$. in the continuum limit. The systematic error includes\nthe errors within the quenched approximation but not the errors of quenching.\nWe also obtain the ratio of decay constants,\n$f_{bs}/f_{bd}=1.17(2)^{+12}_{-6}$. For the B parameters we find $B_{bs}(2\nGeV)=B_{bd}(2 GeV)=1.02(13)$; we cannot resolve the SU(3) breaking effects in\nthis case.",
        "positive": "Review of Unquenched Results: One of the major frontiers of lattice field theory is the inclusion of light\nfermions in simulations, particularly in pursuit of accurate, first principles\npredictions from lattice QCD. With dedicated Teraflops-scale computers\ncurrently simulating QCD, another step towards precision full QCD simulations\nis underway. In addition to ongoing staggered and Wilson fermion simulations,\nfirst results from full QCD with domain wall fermions are available. After some\ndiscussion of work toward better algorithms, simulations completed to date will\nbe discussed."
    },
    {
        "anchor": "Semileptonic decays $B\\rightarrow D^{(*)}l\u03bd$ at nonzero recoil: We have analyzed the semileptonic decays $B\\rightarrow D\\ell\\nu$ and\n$B\\rightarrow D^*\\ell\\nu$ on the full suite of MILC (2+1)-flavor asqtad\nensembles with lattice spacings as small as 0.045 fm and light-to-strange-quark\nmass ratios as low as 1/20. We use the Fermilab interpretation of the clover\naction for heavy valence quarks and the asqtad action for light valence quarks.\nWe compute the hadronic form factors for $B\\rightarrow D$ at both zero and\nnonzero recoil and for $B\\rightarrow D^*$ at zero recoil. We report our results\nfor $|V_{cb}|$.",
        "positive": "Noisy Monte Carlo revisited: We present an exact Monte Carlo algorithm designed to sample theories where\nthe energy is a sum of many couplings of decreasing strength. Our algorithm,\nsimplified from that of L. Lin et al. hep-lat/9905033, avoids the computation\nof almost all non-leading terms. We illustrate its use by simulating SU(2)\nlattice gauge theory with a 5-loop action, and discuss further applications to\nfull QCD."
    },
    {
        "anchor": "Multipoint reweighting method and its applications to lattice QCD: The reweighting method is widely used in numerical studies of QCD, in\nparticular, for the cases in which the conventional Monte-Carlo method cannot\nbe applied directly, e.g., finite density QCD. However, the application range\nof the reweighing method is restricted due to several problems. One of the most\nsevere problems here is the overlap problem. To solve it, we examine a\nmultipoint reweighting method in which simulations at several simulation points\nare combined in the data analyses. We systematically study the applicability\nand limitation of the multipoint reweighting method in two-flavor QCD at zero\ndensity. Measuring histograms of physical quantities at a series of simulation\npoints, we apply the multipoint reweighting method to calculate the meson\nmasses as continuous functions of the gauge coupling $\\beta$ and the hopping\nparameters $\\kappa$. We then determine lines of constant physics and beta\nfunctions, which are needed in a calculation of the equation of state at finite\ntemperature.",
        "positive": "'t Hooft loop and the phases of SU(2) LGT: We analyze the vacuum structure of SU(2) lattice gauge theories in D=2,3,4,\nconcentrating on the stability of 't Hooft loops. High precision calculations\nhave been performed in D=3; similar results hold also for D=4 and D=2. We\ndiscuss the impact of our findings on the continuum limit of Yang-Mills\ntheories."
    },
    {
        "anchor": "More on random-lattice fermions: The lattice fermion determinants, in a given background gauge field, are\nevaluated for two different kinds of random lattices and compared to those of\nnaive and wilson fermions in the continuum limit. While the fermion doubling is\nconfirmed on one kind of lattices, there is positive evidence that it may be\nabsent for the other, at least for vector interactions in two dimensions.\nCombined with previous studies, arbitrary randomness by itself is shown to be\nnot a sufficient condition to remove the fermion doublers.",
        "positive": "Lattice QCD Analysis for Gluons: Nonperturbative properties of gluons are studied in SU(3) lattice QCD at the\nquenched level. The first subject is a functional-form analysis of the gluon\npropagator $D_{\\mu\\nu}^{ab}(x)$ in the Landau gauge. We find that the gluon\npropagator $D_{\\mu\\mu}^{aa}(r)$ obtained in lattice QCD is well described by\nthe four-dimensional (4D) Yukawa-type function $e^{-mr}/r$ with $m \\simeq\n600$MeV for the Euclidean 4D distance $r = 0.1 \\sim 1.0$ fm. In momentum space,\nthe gluon propagator $\\tilde D_{\\mu\\mu}^{aa}(p^2)$ ($p= 0.5 \\sim 3$ GeV) is\nfound to be well approximated with a new-type propagator of $(p^2+m^2)^{-3/2}$,\nwhich corresponds to 4D Fourier image of the Yukawa-type function. Associated\nwith the Yukawa-type gluon propagator, we derive analytical expressions for the\nzero-spatial-momentum propagator $D_0(t)$, the effective mass $M_{\\rm eff}(t)$,\nand the spectral function $\\rho(\\omega)$ of the gluon field. The mass parameter\n$m$ turns out to be the infrared effective mass of gluons. The obtained gluon\nspectral function $\\rho(\\omega)$ is almost negative-definite for $\\omega >m$,\nexcept for a positive $\\delta$-functional peak at $\\omega=m$. The second\nsubject is a lattice-QCD determination of the relevant gluonic\nmomentum-component for color confinement. As a remarkable fact, the string\ntension is found to be almost unchanged even after cutting off the\nhigh-momentum gluon component above 1.5 GeV in the Landau gauge. In fact, the\nrelevant gluonic scale for color confinement is concluded to be below 1.5 GeV."
    },
    {
        "anchor": "A faster method of computation of lattice quark number susceptibilities: We compute the quark number susceptibilities in two flavor QCD for staggered\nfermions by adding the chemical potential as a Lagrange multiplier for the\npoint-split number density term. Since lesser number of quark propagators are\nrequired at any order, this method leads to faster computations. We propose a\nsubtraction procedure to remove the inherent undesired lattice terms and check\nthat it works well by comparing our results with the existing ones where the\nelimination of these terms is analytically guaranteed. We also show that the\nratios of susceptibilities are robust, opening a door for better estimates of\nlocation of the QCD critical point through the computation of the tenth and\ntwelfth order baryon number susceptibilities without significant additional\ncomputational overload.",
        "positive": "Lattice QCD Calculation of Electroweak Box Contributions to Superallowed\n  Nuclear and Neutron Beta Decays: We present the first lattice QCD calculation of the universal axial $\\gamma\nW$-box contribution $\\square_{\\gamma W}^{VA}$ to both superallowed nuclear and\nneutron beta decays. This contribution emerges as a significant component\nwithin the theoretical uncertainties surrounding the extraction of $|V_{ud}|$\nfrom superallowed decays. Our calculation is conducted using two domain wall\nfermion ensembles at the physical pion mass. To construct the nucleon 4-point\ncorrelation functions, we employ the random sparsening field technique.\nFurthermore, we incorporate long-distance contributions to the hadronic\nfunction using the infinite-volume reconstruction method. Upon performing the\ncontinuum extrapolation, we arrive at $\\square_{\\gamma\nW}^{VA}=3.65(8)_{\\mathrm{lat}}(1)_{\\mathrm{PT}}\\times10^{-3}$. Consequently,\nthis yields a slightly higher value of\n$|V_{ud}|=0.97386(11)_{\\mathrm{exp.}}(9)_{\\mathrm{RC}}(27)_{\\mathrm{NS}}$,\nreducing the previous $2.1\\sigma$ tension with the CKM unitarity to\n$1.8\\sigma$. Additionally, we calculate the vector $\\gamma W$-box contribution\nto the axial charge $g_A$, denoted as $\\square_{\\gamma W}^{VV}$, and explore\nits potential implications."
    },
    {
        "anchor": "Dynamic Critical Behavio(u)r of a Cluster Algorithm for the\n  Ashkin--Teller Model: We study the dynamic critical behavior of a Swendsen--Wang--type algorithm\nfor the Ashkin--Teller model. We find that the Li--Sokal bound on the\nautocorrelation time ($\\tau_{{\\rm int},{\\cal E}} \\ge {\\rm const} \\times C_H$)\nholds along the self-dual curve of the symmetric Ashkin--Teller model, but this\nbound is apparently not sharp. The ratio $\\tau_{{\\rm int},{\\cal E}}/C_H$\nappears to tend to infinity either as a logarithm or as a small power ($0.05\n\\ltapprox p \\ltapprox 0.12$).",
        "positive": "Percolation and Deconfinement in SU(2) Gauge Theory: The deconfinement transition in SU(2) gauge theory and the magnetization\ntransition in the Ising model belong to the same universality class. The\ncritical behaviour of the Ising model can be characterized either as\nspontaneous breaking of the $Z_2$ symmetry of spin states or as percolation of\nappropriately defined spin clusters. We show that deconfinement in SU(2) gauge\ntheory can be specified as percolation of Polyakov loop clusters with\nFortuin-Kasteleyn bond weights, leading to the same critical exponents as the\nconventional order-disorder description based on the Polykov loop expectation\nvalue."
    },
    {
        "anchor": "Hamiltonian limit of lattice QED in 2+1 dimensions: The Hamiltonian limit of lattice gauge theories can be found by extrapolating\nthe results of anisotropic lattice computations, i.e., computations using\nlattice actions with different temporal and spatial lattice spacings ($a_t\\neq\na_s$), to the limit of $a_t\\to 0$. In this work, we present a study of this\nHamiltonian limit for a Euclidean $U(1)$ gauge theory in 2+1 dimensions (QED3),\nregularized on a toroidal lattice. The limit is found using the renormalized\nanisotropy $\\xi_R=a_t/a_s$, by sending $\\xi_R \\to 0$ while keeping the spatial\nlattice spacing constant. We compute $\\xi_R$ in $3$ different ways: using both\nthe ``normal'' and the ``sideways'' static quark potential, as well as the\ngradient flow evolution of gauge fields. The latter approach will be\nparticularly relevant for future investigations of combining quantum\ncomputations with classical Monte Carlo computations, which requires the\nmatching of lattice results obtained in the Hamiltonian and Lagrangian\nformalisms.",
        "positive": "Nucleon Form Factors with 2+1 Flavors of Domain Wall Fermions and\n  All-Mode-Averaging: We report recent progress in the calculations of the isovector nucleon\nelectromagnetic form factors using 2+1 flavors of domain wall fermions at pion\nmasses of 170 MeV and 250 MeV. The lattice size is fixed at $32^3\\times64$ with\na lattice cutoff scale of 1.37(1) GeV. For the calculations with $M_\\pi = 170$\nMeV, we employed the All-Mode-Averaging (AMA) technique, which led to roughly a\nfactor of 20 improvement in computational efficiency and has reduced the\nstatistical errors in our results significantly. We were also able to do\ncalculations at two different source-sink separations, at roughly 1.3 fm and\n1.0 fm, without much additional cost by reusing the low eigen-modes stored for\nthe AMA calculations. We will present results for the isovector form factors\nand their derived quantities, including the Dirac and Pauli radii, anomalous\nmagnetic moment and discuss the effects of possible excited-state\ncontaminations. Connected contributions to the isoscalar Dirac and Pauli form\nfactors will also be shown."
    },
    {
        "anchor": "k-String tensions and their large-N dependence: We consider whether the 1/N corrections to k-string tensions must begin at\norder 1/N^2, as in the Sine Law, or whether odd powers of 1/N, as in Casimir\nScaling, are also acceptable. The issue is important because different models\nof confinement differ in their predictions for the representation-dependence of\nk-string tensions, and corrections involving odd powers of 1/N would seem to be\nruled out by the large-N expansion. We show, however, that k-string tensions\nmay, in fact, have leading 1/N corrections, and consistency with the large-N\nexpansion, in the open string sector, is achieved by an exact pairwise\ncancellation among terms involving odd powers of 1/N in particular combinations\nof Wilson loops. It is shown how these cancellations come about in a concrete\nexample, namely, strong coupling lattice gauge theory with the heat-kernel\naction, in which k-string tensions follow the Casimir scaling rule.",
        "positive": "Accelerating QDP++/Chroma on GPUs: Extensions to the C++ implementation of the QCD Data Parallel Interface are\nprovided enabling acceleration of expression evaluation on NVIDIA GPUs. Single\nexpressions are off-loaded to the device memory and execution domain leveraging\nthe Portable Expression Template Engine and using Just-in-Time compilation\ntechniques. Memory management is automated by a software implementation of a\ncache controlling the GPU's memory. Interoperability with existing Krylov space\nsolvers is demonstrated and special attention is paid on 'Chroma readiness'.\nNon-kernel routines in lattice QCD calculations typically not subject of\nhand-tuned optimisations are accelerated which can reduce the effects otherwise\nsuffered from Amdahl's Law."
    },
    {
        "anchor": "Regulator dependence of inhomogeneous phases in the 2+1-dimensional\n  Gross-Neveu model: The phase diagram of the Gross-Neveu model in $2+1$ space-time dimensions at\nnon-zero temperature and chemical potential is studied in the limit of\ninfinitely many flavors, focusing on the possible existence of inhomogeneous\nphases, where the order parameter $\\sigma$ is non-uniform in space. To this\nend, we analyze the stability of the energetically favored homogeneous\nconfiguration $\\sigma(\\textbf{x}) = \\bar\\sigma = \\textrm{const}$ with respect\nto small inhomogeneous fluctuations, employing lattice field theory with two\ndifferent lattice discretizations as well as a continuum approach with\nPauli-Villars regularization. Within lattice field theory, we also perform a\nfull minimization of the effective action, allowing for arbitrary 1-dimensional\nmodulations of the order parameter. For all methods special attention is paid\nto the role of cutoff effects. For one of the two lattice discretizations, no\ninhomogeneous phase was found. For the other lattice discretization and within\nthe continuum approach with a finite Pauli-Villars cutoff parameter $\\Lambda$,\nwe find a region in the phase diagram where an inhomogeneous order parameter is\nfavored. This inhomogeneous region shrinks, however, when $a$ is decreased or\n$\\Lambda$ is increased, and finally diappears for all non-zero temperatures\nwhen the cutoff is removed completely. For vanishing temperature, we find hints\nfor a degeneracy of homogeneous and inhomogeneous solutions, in agreement with\nearlier findings.",
        "positive": "Lattice QCD calculation of light sterile neutrino contribution in\n  $0\\nu2\u03b2$ decay: We present a lattice QCD study of the neutrinoless double beta decay\ninvolving light sterile neutrinos. The calculation is performed at physical\npion mass using five gauge ensembles generated with the $2+1$-flavor domain\nwall fermions. We obtain the low-energy constants\n$g_{\\text{LR}}^{\\pi\\pi}(m_\\nu)$ with the neutrino mass $m_\\nu$ from $0$ GeV to\n$3$ GeV. The lattice results are reasonably consistent with the previous\ninterpolation method with a $\\sim20\\%$ deviation at small $m_\\nu$. We provide\nan explanation on the discrepancy at vanishing neutrino mass. At large $m_\\nu$,\na good consistence between our results and the previous lattice determination\nof $g_{4}^{\\pi\\pi}(\\mu)$ is found at $\\mu=m_\\nu=3$ GeV."
    },
    {
        "anchor": "Systematic errors in partially-quenched QCD plus QED lattice simulations: At the precision reached in current lattice QCD calculations, electromagnetic\neffects are becoming numerically relevant. Here, electromagnetic effects are\nincluded by superimposing $\\mathrm{U}(1)$ degrees of freedom on $N_f = 2+1$ QCD\nconfigurations from the Budapest-Marseille-Wuppertal Collaboration. We present\npreliminary results for the electromagnetic corrections to light pseudoscalars\nmesons masses and discuss some of the associated systematic errors.",
        "positive": "From chiral symmetry breaking to conformality in SU(2) gauge theory: We compute the spectrum of SU(2) gauge theory with two, four or six Dirac\nfermions in the fundamental representation of the gauge group. We investigate\nthe scaling of the meson masses as a function of the quark mass when\napproaching the chiral limit. We find behavior compatible with the usual\npattern of chiral symmetry breaking at $N_f\\le 4$ and with the existence of an\ninfrared fixed point at $N_f=6$. In the six flavor case we determine the\nanomalous dimension of the quark mass operator from the spectrum and find\nresults fully consistent with earlier analyses."
    },
    {
        "anchor": "Studying a relativistic field theory at finite chemical potential with\n  the density matrix renormalization group: The density matrix renormalization group is applied to a relativistic complex\nscalar field at finite chemical potential. The two-point function and various\nbulk quantities are studied. It is seen that bulk quantities do not change with\nthe chemical potential until it is larger than the minimum excitation energy.\nThe technical limitations of the density matrix renormalization group for\ntreating bosons in relativistic field theories are discussed. Applications to\nother relativistic models and to nontopological solitons are also suggested.",
        "positive": "Unveiling SU(3) Flux Tubes At Nonzero Temperature: Electric Fields and\n  Magnetic Currents: We report on the results of measuring the chromoelectric fields in a flux\ntube created by a static quark-antiquark pair in the finite-temperature SU(3)\ngauge theory. Below the deconfinement temperature the field behavior is similar\nto the zero-temperature case. Above the deconfinement temperature the field\nshape remains the same, but the field values drop when the distance between\nquark and antiquark increases, thus showing the disappearance of confining\npotential."
    },
    {
        "anchor": "Highly excited pure gauge SU(3) flux tubes: Flux tube spectra are expected to have full towers of levels due to the\nquantization of the string vibrations. We study a spectrum of flux tubes with\nstatic quark and antiquark sources with pure gauge $SU(3)$ lattice QCD in 3+1\ndimensions up to a significant number of excitations. To go high in the\nspectrum, we specialize in the most symmetric case $\\Sigma_g^+$, use a large\nset of operators, solve the generalized eigenvalue and compare different\nlattice QCD gauge actions and anisotropies.",
        "positive": "Low-Temperature Series Expansions for the Spin-1 Ising Model: The finite lattice method of series expansion has been used to extend\nlow-temperature series for the partition function, order parameter and\nsusceptibility of the spin-1 Ising model on the square lattice. A new formalism\nis described that uses two distinct transfer matrix approaches in order to\nsignificantly reduce computer memory requirements and which permits the\nderivation of the series to 79th order. Subsequent analysis of the series\nclearly confirms that the spin-1 model has the same dominant critical exponents\nas the spin-$\\frac{1}{2}$ Ising model. Accurate estimates for both the critical\ntemperature and non-physical singularities are obtained. In addition, evidence\nfor a non-analytic confluent correction with exponent $\\Delta_{1} = 1.1 \\pm\n0.1$ is found."
    },
    {
        "anchor": "A gauge invariant Debye mass for the complex heavy-quark potential: The concept of a screening mass is a powerful tool to simplify the intricate\nphysics of in-medium test charges surrounded by light charge carriers. While it\nhas been successfully used to describe electromagnetic properties, its\ndefinition and computation in QCD is plagued by questions of gauge invariance\nand the presence of non-perturbative contributions from the magnetic sector.\nHere we present a recent alternative definition of a gauge invariant Debye mass\nparameter following closely the original idea of Debye and Hueckel. Our test\ncharges are a static heavy quark-antiquark pair whose complex potential and its\nin-medium modification can be extracted using lattice QCD. By combining in a\ngeneralized Gauss-Law the non-perturbative aspects of quark binding with a\nperturbative ansatz for the medium effects, we succeed to describe the lattice\nvalues of the potential with a single temperature dependent parameter, in turn\nidentified with a Debye mass. We find that its behavior, as evaluated in a\nrecent quenched lattice QCD study, deviates from that in other approaches, such\nas hard-thermal-loop perturbation theory or from electric field correlators on\nthe lattice. In particular around the phase transition its values tend to zero\nsignificantly faster than at weak-coupling.",
        "positive": "\"Confinement Mechanism in Various Abelian Projections of $SU(2)$ Lattice\n  Gluodynamics\": We show that the monopole confinement mechanism in lattice gluodynamics is a\nparticular feature of the maximal abelian projection. We give an explicit\nexample of the $SU(2) \\rightarrow U(1)$ projection (the minimal abelian\nprojection), in which the confinement is due to topological objects other than\nmonopoles. We perform analytical and numerical study of the loop expansion of\nthe Faddeev--Popov determinant for the maximal and the minimal abelian\nprojections, and discuss the fundamental modular region for these projections."
    },
    {
        "anchor": "On the reliable measurement of the gluon condensate in lattice QCD: We propose to calculate the gluon condensate in lattice QCD in an indirect\nway by extracting it from the correlator of hadronic currents of heavy quarks.\nMoments (derivatives with respect to momentum at vanishing momentum) of the\nvector and pseudoscalar correlators are evaluated. The contribution of the\ncontinuum spectrum in addition to the low-lying resonance is observed in\naccordance with qualitative expectations. Finite size effects are observed and\nshown to be insignificant for heavy quarks and moderate lattices. A practical\ndefinition of the nonperturbatively renormalized heavy quark mass is given.",
        "positive": "Observing dynamical supersymmetry breaking with euclidean lattice\n  simulations: A strict positivity of the ground-state energy is a necessary and sufficient\ncondition for spontaneous supersymmetry breaking. This ground-state energy may\nbe directly determined from the expectation value of the Hamiltonian in the\nfunctional integral, defined with an \\emph{antiperiodic} temporal boundary\ncondition for all fermionic variables. We propose to use this fact to observe\nthe dynamical spontaneous supersymmetry breaking in Euclidean lattice\nsimulations. If a lattice formulation possesses a manifestly preserved\nfermionic symmetry, there exists a natural choice of a Hamiltonian operator\nthat is consistent with a topological nature of the Witten index. We\nnumerically confirm the validity of our idea in models of supersymmetric\nquantum mechanics. We further examine the possibility of dynamical\nsupersymmetry breaking in the two-dimensional $\\mathcal{N}=(2,2)$ super\nYang-Mills theory with the gauge group SU(2), for which the Witten index is\nunknown. Although statistical errors are still large, we do not observe\npositive ground-state energy, at least within one standard deviation. This\nprompts us to draw a different conclusion from a recent conjectural claim that\nsupersymmetry is dynamically broken in this system."
    },
    {
        "anchor": "Magnetic monopole dominance for the Wilson loops in higher\n  representations: The dual superconductor picture is one of the most promising scenarios for\nquark confinement. To investigate this picture in a gauge-invariant manner, we\nhave proposed a new formulation of Yang-Mills theory, named the decomposition\nmethod, on the lattice. The so-called restricted field obtained from the\ngauge-covariant decomposition plays the dominant role in quark confinement. It\nhas been known by preceding works that the restricted-field dominance is not\nobserved for the Wilson loop in higher representations if the restricted part\nof the Wilson loop is obtained by adopting the Abelian projection or the field\ndecomposition naively in the same way as done in the fundamental\nrepresentation. Recently, through the non-Abelian Stokes theorem (NAST) for the\nWilson loop operator, we have proposed suitable gauge-invariant operators\nconstructed from the restricted field to reproduce the correct behavior of the\noriginal Wilson loop averages for higher representations. We have demonstrated\nthe numerical evidence for the restricted-field dominance in the string\ntension.\n  In this talk, we focus on the magnetic monopole. According to this picture,\nmagnetic monopoles causing the dual superconductivity are the dominant degrees\nof freedom responsible for confinement. With the help of the NAST, we define\nthe magnetic monopole and the string tension extracted from the\nmagnetic-monopole part of the Wilson loop in a gauge-invariant manner. We will\nfurther perform lattice simulations to measure the static potential for quarks\nin higher representations using the proposed operators and examine the magnetic\nmonopole dominance in the string tension, which means that the string tension\nextracted from the magnetic-monopole part of the Wilson loop reproduces the\nproper string tension obtained from the original Wilson loop.",
        "positive": "I=2 pi-pi Scattering from Fully-Dynamical Mixed-Action Lattice QCD: We compute the I=2 pi-pi scattering length at pion masses of m_pi ~ 294, 348\nand 484 MeV in fully-dynamical lattice QCD using Luscher's finite-volume\nmethod. The calculation is performed with domain-wall valence-quark propagators\non asqtad-improved MILC configurations with staggered sea quarks at a single\nlattice spacing, b ~ 0.125 fm. Chiral perturbation theory is used to perform\nthe extrapolation of the scattering length from lattice quark masses down to\nthe physical value, and we find m_pi a_2 = -0.0426 +- 0.0006 +- 0.0003 +-\n0.0018, in good agreement with experiment. The I=2 pi-pi scattering phase shift\nis calculated to be delta = -43 +- 10 +- 5 degrees at |p| ~ 544 MeV for m_pi ~\n484 MeV."
    },
    {
        "anchor": "QCD simulations at small chemical potential: Within the reweighting approach, one has the freedom to choose the Monte\nCarlo action so that it provides a good overlap with the finite-\\mu measure but\nremains simple to simulate. We explore several choices of action in the regime\nof small \\mu. Simulating with a finite isospin chemical potential \\mu_I=\\mu\ngives a better overlap than the standard choice \\mu=0, with no computational\noverhead.",
        "positive": "Practical Implementation of Lattice QCD Simulation on Intel Xeon Phi\n  Knights Landing: We investigate implementation of lattice Quantum Chromodynamics (QCD) code on\nthe Intel Xeon Phi Knights Landing (KNL). The most time consuming part of the\nnumerical simulations of lattice QCD is a solver of linear equation for a large\nsparse matrix that represents the strong interaction among quarks. To establish\nwidely applicable prescriptions, we examine rather general methods for the SIMD\narchitecture of KNL, such as using intrinsics and manual prefetching, to the\nmatrix multiplication and iterative solver algorithms. Based on the performance\nmeasured on the Oakforest-PACS system, we discuss the performance tuning on KNL\nas well as the code design for facilitating such tuning on SIMD architecture\nand massively parallel machines."
    },
    {
        "anchor": "Lattice QCD determination of patterns of excited baryon states: Energies for excited isospin I=1/2 and I=3/2 states that include the nucleon\nand Delta families of baryons are computed using quenched, anisotropic\nlattices. Baryon interpolating field operators that are used include nonlocal\noperators that provide G_2 irreducible representations of the octahedral group.\nThe decomposition of spin 5/2 or higher spin states is realized for the first\ntime in a lattice QCD calculation. We observe patterns of degenerate energies\nin the irreducible representations of the octahedral group that correspond to\nthe subduction of the continuum spin 5/2 or higher. The overall pattern of\nlow-lying excited states corresponds well to the pattern of physical states\nsubduced to the irreducible representations of the octahedral group.",
        "positive": "Numerical stochastic perturbation theory applied to the twisted\n  Eguchi-Kawai model: We present the results of an exploratory study of the numerical stochastic\nperturbation theory (NSPT) applied to the four dimensional twisted Eguchi-Kawai\n(TEK) model. We employ a Kramers type algorithm based on the Generalized Hybrid\nMolecular Dynamics (GHMD) algorithm. We have computed the perturbative\nexpansion of square Wilson loops up to $O(g^8)$. The results of the first two\ncoefficients (up to $O(g^4)$) have a high precision and match well with the\nexact values. The next two coefficients can be determined and even extrapolated\nto large $N$, where they should coincide with the corresponding coefficients\nfor ordinary Yang-Mills theory on an infinite lattice. Our analysis shows the\nbehaviour of the probability distribution for each coefficient tending to\nGaussian for larger $N$. The results allow us to establish the requirements to\nextend this analysis to much higher order."
    },
    {
        "anchor": "Nucleon Form Factors from the Feynman-Hellmann Method in Lattice QCD: Lattice QCD calculations of the nucleon electromagnetic form factors are of\ninterest at both the high and low momentum transfer regions. For high momentum\ntransfers especially there are open questions which require more intense study,\nsuch as the potential zero crossing in the proton's electric form factor. We\nwill present recent progress from the QCDSF/UKQCD/CSSM collaboration on the\ncalculation of these form factors using the Feynman-Hellmann method in lattice\nQCD. The Feynman-Hellmann method allows for greater control over excited states\nwhich we take advantage of by going to high values of the momentum transfer. In\nthis proceeding we present results of the form factors up to $6\n\\textrm{GeV}^{2}$, using $N_{f}=2+1$ flavour fermions for three different pion\nmasses in the range 310-470 $\\textrm{MeV}$. The results are extrapolated to the\nphysical pion mass through the use of a flavour breaking expansion.",
        "positive": "Green's Function Monte Carlo study of SU(3) lattice gauge theory in\n  (3+1)D: A `forward walking' Green's Function Monte Carlo algorithm is used to obtain\nexpectation values for SU(3) lattice Yang-Mills theory in (3+1) dimensions. The\nground state energy and Wilson loops are calculated, and the finite-size\nscaling behaviour is explored. Crude estimates of the string tension are\nderived, which agree with previous results at intermediate couplings; but more\naccurate results for larger loops will be required to establish scaling\nbehaviour at weak coupling."
    },
    {
        "anchor": "Quantum Chaos in Compact Lattice QED: Complete eigenvalue spectra of the staggered Dirac operator in quenched $4d$\ncompact QED are studied on $8^3 \\times 4$ and $8^3 \\times 6$ lattices. We\ninvestigate the behavior of the nearest-neighbor spacing distribution $P(s)$ as\na measure of the fluctuation properties of the eigenvalues in the strong\ncoupling and the Coulomb phase. In both phases we find agreement with the\nWigner surmise of the unitary ensemble of random-matrix theory indicating\nquantum chaos. Combining this with previous results on QCD, we conjecture that\nquite generally the non-linear couplings of quantum field theories lead to a\nchaotic behavior of the eigenvalues of the Dirac operator.",
        "positive": "Weak Coupling Limit of U(1) Lattice Model in Fourier Basis: The transfer-matrix of the U(1) lattice model is considered in the Fourier\nbasis and in the weak coupling limit. The issues of Gauss law constraint and\ngauge invariant states are addressed in the Fourier basis. In particular, it is\nshown that in the strong coupling limit the gauge invariant Fourier states are\neffectively the finite size closed loop currents. In the weak coupling limit,\nhowever, the link-currents along periodic or infinite spatial directions find\ncomparable roles as gauge invariant states. The subtleties related to the\nextreme weak coupling of the transfer-matrix in the Fourier basis are\ndiscussed. A careful analysis of the zero eigenvalues of the matrix in the\nquadratic action leads to a safe extraction of the diverging group volume in\nthe limit $g\\to 0$. By means of the very basic notions and tools of the lattice\nmodel, the spectrum at the weak coupling limit for any dimension and size of\nlattice is obtained analytically. The spectrum at the weak coupling limit\ncorresponds to the expected one by the continuum model in the large lattice\nlimit."
    },
    {
        "anchor": "The chiral phase transition for two-flavour QCD at imaginary and zero\n  chemical potential: The chiral symmetry of QCD with two massless quark flavours gets restored in\na non-analytic chiral phase transition at finite temperature and zero density.\nWhether this is a first-order or a second-order transition has not yet been\ndetermined unambiguously, due to the difficulties of simulating light quarks.\nWe investigate the nature of the chiral transition as a function of quark mass\nand imaginary chemical potential, using staggered fermions on N_t=4 lattices.\nAt sufficiently large imaginary chemical potential, a clear signal for a\nfirst-order transition is obtained for small masses, which weakens with\ndecreasing imaginary chemical potential. The second-order critical line\nm_c(mu_i), which marks the boundary between first-order and crossover\nbehaviour, extrapolates to a finite m_c(mu_i=0) with known critical exponents.\nThis implies a definitely first-order transition in the chiral limit on\nrelatively coarse, N_t=4 lattices.",
        "positive": "Vacuum structure of pure gauge theories on the lattice: We present results from simulations on two aspects of quark confinement in\nthe pure gauge sector. First is the calculation of the profile of the flux tube\nconnecting a static $q \\bar{q}$ pair in $SU(2)$. By using the Michael sum rules\nas a constraint we give evidence that the energy density at the center of the\nflux tube goes to a constant as a function of quark separation. Slow variation\nof the width and energy density is not ruled out. Secondly in the confined\nphase of lattice $U(1)$ we calculate the curl of the magnetic monopole current\nand show that the dual London equation is satisfied and that the electric\nfluxoid is quantized."
    },
    {
        "anchor": "Phase transition and dynamical-parameter method in U(1) gauge theory: Monte Carlo simulations of the 4-dimensional compact U(1) lattice gauge\ntheory in the neighborhood of the transition point are made difficult by the\nsuppression of tunneling between the phases, which becomes very strong as soon\nas the volume of the lattice grows to any appreciable size. This problem can be\navoided by making the monopole coupling a dynamical variable. In this manner\none can circumvent the tunneling barrier by effectively riding on top of the\npeaks in the energy distribution which meet for sufficiently large monopole\ncoupling. Here we present an efficient method for determining the parameters\nneeded for this procedure, which can thus be implemented at low computational\ncost also on large lattices. This is particularly important for a reliable\ndetermination of the transition point. We demonstrate the working of our method\non a 16^4 lattice. We obtain an equidistribution of configurations across the\nphase transition even for such a relatively large lattice size.",
        "positive": "Aspects of SU(3) baryon extrapolation: We report on a recent chiral extrapolation, based on an SU(3) framework, of\noctet baryon masses calculated in 2+1-flavour lattice QCD. Here we further\nclarify the form of the extrapolation, the estimation of the infinite-volume\nlimit, the extracted low-energy constants and the corrections in the\nstrange-quark mass."
    },
    {
        "anchor": "QCD strings ending on domain walls --- a complete wetting phenomenon in\n  SUSY QCD: In the context of M-theory, Witten has argued that an intriguing phenomenon\noccurs, namely that QCD strings can end on domain walls. We present a simpler\nexplanation of this effect using effective field theory to describe the\nbehavior of the Polyakov loop and the gluino condensate in N = 1 supersymmetric\nQCD. We describe how domain walls separating distinct confined phases appear in\nthis effective theory and how these interfaces are completely wet by a film of\ndeconfined phase at the high-temperature phase transition. This gives the\nPolyakov loop a non-zero expectation value on the domain wall. Consequently, a\nstatic test quark which is close to the interface has a finite free energy and\nthe string emanating from it can end on the wall.",
        "positive": "Neutron electric dipole moment from lattice QCD: We carry out a feasibility study for the lattice QCD calculation of the\nneutron electric dipole moment (NEDM) in the presence of the $\\theta$ term. We\ndevelop the strategy to obtain the nucleon EDM from the CP-odd electromagnetic\nform factor $F_3$ at small $\\theta$, in which NEDM is given by $\\lim_{q^2\\to\n0}\\theta F_3(q^2)/(2m_N)$ where $q$ is the momentum transfer and $m_N$ is the\nnucleon mass. We first derive a formula which relates $F_3$, a matrix element\nof the electromagnetic current between nucleon states, with vacuum expectation\nvalues of nucleons and/or the current. In the expansion of $\\theta$, the\nparity-odd part of the nucleon-current-nucleon three-point function contains\ncontributions not only from the parity-odd form factors but also from the\nparity-even form factors multiplied by the parity-odd part of the nucleon\ntwo-point function, and therefore the latter contribution must be subtracted to\nextract $F_3$. We then perform an explicit lattice calculation employing the\ndomain-wall quark action with the RG improved gauge action in quenched QCD at\n$a^{-1}\\simeq 2$ GeV on a $16^3\\times 32\\times 16$ lattice. At the quark mass\n$m_f a =0.03$, corresponding to $m_\\pi/m_\\rho \\simeq 0.63$, we accumulate 730\nconfigurations, which allow us to extract the parity-odd part in both two- and\nthree-point functions. Employing two different Dirac $\\gamma$ matrix\nprojections, we show that a consistent value for $F_3$ cannot be obtained\nwithout the subtraction described above. We obtain $F_3(q^2\\simeq 0.58\n\\textrm{GeV}^2)/(2m_N) =$ $-$0.024(5) $e\\cdot$fm for the neutron and\n$F_3(q^2\\simeq 0.58 \\textrm{GeV}^2)/(2m_N) =$ 0.021(6) $e\\cdot$fm for the\nproton."
    },
    {
        "anchor": "Dynamical quark mass generation: Taking inspiration from lattice QCD results, we argue that a non-perturbative\nmass term for fermions can be generated as a consequence of the dynamical\nphenomenon of spontaneous chiral symmetry breaking, in turn triggered by the\nexplicitly breaking of chiral symmetry induced by the critical Wilson term in\nthe action. In a pure lattice QCD-like theory this mass term cannot be\nseparated from the unavoidably associated linearly divergent contribution.\nHowever, if QCD with a Wilson term is enlarged to a theory where also a scalar\nfield is present, coupled to a doublet of SU(2) fermions via a Yukawa\ninteraction, then in the phase where the scalar field takes a non-vanishing\n(large) expectation value, a dynamically generated and ``naturally'' light\nfermion mass (numerically unrelated to the expectation value of the scalar\nfield) is seen to emerge, at a critical value of the Yukawa coupling where the\nsymmetry of the model is maximally enhanced.",
        "positive": "Renormalization Group Flow in non-compact QED with two charged staggered\n  Fermions: We have investigated a system with two sets of staggered fermions with\ncharges 1 and -1/2 coupling to a non-compact U(1) gauge field in 4 dimensions.\nThe model exhibits breaking of chiral symmetries of both fermions at different\nvalues of beta. Chiral condensates, renormalized fermion masses and\nrenormalized charges have been measured. The renormalized charges show\nagreement with one-loop perturbation theory. We examine surfaces of constant\nrenormalized charges in the space of bare parameters."
    },
    {
        "anchor": "Higgs and W boson spectrum from lattice simulations: The spectrum of energy levels is computed for all available angular momentum\nand parity quantum numbers in the SU(2)-Higgs model, with parameters chosen to\nmatch experimental data from the Higgs-W boson sector of the standard model.\nSeveral multi-boson states are observed, with and without linear momentum, and\nall are consistent with weakly-interacting Higgs and W bosons. The creation\noperators used in this study are gauge-invariant so, for example, the Higgs\noperator is quadratic rather than linear in the Lagrangian's scalar field.",
        "positive": "The Conformal Mode in 2D Simplicial Gravity: We verify that summing 2D DT geometries correctly reproduces the Polyakov\naction for the conformal mode, including all ghost contributions, at large\nvolumes. The Gaussian action is reproduced even for c=10, well into the\nbranched polymer phase, which confirms the expectation that the DT measure is\nindeed correct in this regime as well."
    },
    {
        "anchor": "NLO anomalous dimension of multiplicatively renormalizable four-fermion\n  operators in Schroedinger Functional schemes: Renormalization constants for multiplicatively renormalizable parity-odd\nfour-fermion operators are computed in various different Schroedinger\nFunctional (SF) schemes and lattice regularizations with Wilson quarks at\none-loop order in perturbation theory. Our results are used in the calculation\nof their NLO anomalous dimensions, through matching to continuum schemes. They\nalso enable a comparison of the two-loop perturbative RG running to the\npreviously obtained nonperturbative one in the region of small renormalized\ncoupling.",
        "positive": "The gradient flow running coupling scheme: The Yang-Mills gradient flow in finite volume is used to define a running\ncoupling scheme. As our main result the discrete beta-function, or step scaling\nfunction, is calculated for scale change s=3/2 at several lattice spacings for\nSU(3) gauge theory coupled to N_f = 4 fundamental massless fermions. The\ncontinuum extrapolation is performed and agreement is found with the continuum\nperturbative results for small renormalized coupling. The case of SU(2) gauge\ngroup is briefly commented on."
    },
    {
        "anchor": "Two-flavor Simulations of the $\u03c1(770)$ and the Role of the $K\\bar K$\n  Channel: The $\\rho (770)$ meson is the most extensively studied resonance in lattice\nQCD simulations in two ($N_f=2$) and three ($N_f=2+1$) flavor formulations. We\nanalyze $N_f=2$ lattice scattering data using unitarized Chiral Perturbation\nTheory, allowing not only for the extrapolation in mass but also in flavor,\n$N_f=2\\to N_f=2+1$. The flavor extrapolation requires information from a global\nfit to $\\pi\\pi$ and $\\pi K$ phase shifts from experiment. While the chiral\nextrapolation of $N_f=2$ lattice data leads to masses of the $\\rho(770)$ meson\nfar below the experimental one, we find that the missing $K\\bar{K}$ channel is\nable to explain this discrepancy.",
        "positive": "4D $\\mathcal{N}=1$ SYM supercurrent in terms of the gradient flow: The gradient flow and its small flow-time expansion provide a very versatile\nmethod to represent renormalized composite operators in a\nregularization-independent manner. This technique has been utilized to\nconstruct typical Noether currents such as the energy--momentum tensor and the\naxial-vector current in lattice gauge theory. In this paper, we apply the same\ntechnique to the supercurrent in the four-dimensional $\\mathcal{N}=1$ super\nYang--Mills theory (4D $\\mathcal{N}=1$ SYM) in the Wess--Zumino gauge. Since\nthis approach provides a priori a representation of the properly normalized\nconserved supercurrent, our result should be useful, e.g., in lattice numerical\nsimulations of the 4D $\\mathcal{N}=1$ SYM; the conservation of the\nso-constructed supercurrent can be used as a criterion for the supersymmetric\npoint toward which the gluino mass is tuned."
    },
    {
        "anchor": "Universality and RG-improved gauge actions: The reference energy scale r_0 is evaluated for RG-improved Iwasaki and DBW2\ngauge actions (N_f = 0), at values of the deconfinement coupling beta_c\ncorresponding to N_t = 3,4,6,8. The universality of r_0 T_c between Iwasa ki\nand Wilson action is confirmed; the scaling behaviour and the influence of th e\nviolation of positivity in the extraction of effective masses are investigated.",
        "positive": "Clock model interpolation and symmetry breaking in O(2) models: Motivated by recent attempts to quantum simulate lattice models with\ncontinuous Abelian symmetries using discrete approximations, we define an\nextended-O(2) model by adding a $\\gamma \\cos(q\\varphi)$ term to the ordinary\nO(2) model with angular values restricted to a $2\\pi$ interval. In the $\\gamma\n\\rightarrow \\infty$ limit, the model becomes an extended $q$-state clock model\nthat reduces to the ordinary $q$-state clock model when $q$ is an integer and\notherwise is a continuation of the clock model for noninteger $q$. By shifting\nthe $2\\pi$ integration interval, the number of angles selected can change\ndiscontinuously and two cases need to be considered. What we call case $1$ has\none more angle than what we call case $2$. We investigate this class of clock\nmodels in two space-time dimensions using Monte Carlo and tensor\nrenormalization group methods. Both the specific heat and the magnetic\nsusceptibility show a double-peak structure for fractional $q$. In case $1$,\nthe small-$\\beta$ peak is associated with a crossover, and the large-$\\beta$\npeak is associated with an Ising critical point, while both peaks are\ncrossovers in case $2$. When $q$ is close to an integer by an amount $\\Delta q$\nand the system is close to the small-$\\beta$ Berezinskii-Kosterlitz-Thouless\ntransition, the system has a magnetic susceptibility that scales as $\\sim 1 /\n(\\Delta q)^{1 - 1/\\delta'}$ with $\\delta'$ estimates consistent with the\nmagnetic critical exponent $\\delta = 15$. The crossover peak and the Ising\ncritical point move to Berezinskii-Kosterlitz-Thouless transition points with\nthe same power-law scaling. A phase diagram for this model in the $(\\beta, q)$\nplane is sketched. These results are possibly relevant for configurable\nRydberg-atom arrays where the interpolations among phases with discrete\nsymmetries can be achieved by varying continuously the distances among atoms\nand the detuning frequency."
    },
    {
        "anchor": "Screening masses in the SU(3) pure gauge theory and universality: We determine from Polyakov loop correlators the screening masses in th e\ndeconfined phase of the (3+1)d SU(3) pure gauge theory at finite temperature\nnear transition, for two different channels of angular momentum and parity.\nTheir ratio is compared with that of the massive excitations with the same\nquantum numbers in the 3d 3-state Potts model in the broken phase near the\ntransition point at zero magnetic field. Moreover we study the inverse decay\nlength of the correlation between the real parts and between the imaginary\nparts of the Polyakov loop and compare the results with expectations from\nperturbation theory and mean-field Polyakov loop models.",
        "positive": "A comprehensive search for the \u0398^+ pentaquark on the lattice: We study spin 1/2 isoscalar and isovector, even and odd parity candidates for\nthe $\\Theta^+(1540)$ pentaquark particle using large scale lattice QCD\nsimulations. Previous lattice works led to inconclusive results because so far\nit has not been possible to unambiguously identify the known scattering\nspectrum and tell whether additionally a genuine pentaquark state also exists.\nHere we carry out this analysis using several possible wave functions\n(operators). Linear combinations of those have a good chance of spanning both\nthe scattering and pentaquark states. Our operator basis is the largest in the\nliterature, and it also includes spatially non-trivial ones with unit orbital\nangular momentum. The cross correlator we compute is 14$\\times$14 with 60\nnon-vanishing elements. We can clearly distinguish the lowest scattering\nstate(s) in both parity channels up to above the expected location of the\npentaquark, but we find no trace of the latter. Based on that we conclude that\nthere are most probably no pentaquark bound states at our quark masses,\ncorresponding to $m_\\pi$=400--630 MeV. However, we cannot rule out the\nexistence of a pentaquark state at the physical quark mass corresponding to\n$m_\\pi$=135 MeV or pentaquarks with a more exotic wave function."
    },
    {
        "anchor": "Efficient integration of gradient flow in lattice gauge theory and\n  properties of low-storage commutator-free Lie group methods: The smoothing procedure known as the gradient flow that suppresses\nultraviolet fluctuations of gauge fields plays an important role in lattice\ngauge theory calculations. In particular, this procedure is often used for\nhigh-precision scale setting and renormalization of operators. The gradient\nflow equation is defined on the SU(3) manifold and therefore requires\ngeometric, or structure-preserving, integration methods to obtain its numerical\nsolutions. We examine the properties and origins of the three-stage third-order\nexplicit Runge-Kutta Lie group integrator commonly used in the lattice gauge\ntheory community, demonstrate its relation to 2N-storage classical Runge-Kutta\nmethods and explore how its coefficients can be tuned for optimal performance\nin integrating the gradient flow. We also compare the performance of the tuned\nmethod with two third-order variable step size methods. Next, based on the\nrecently established connection between low-storage Lie group integrators and\nclassical 2N-storage Runge-Kutta methods, we study two fourth-order low-storage\nmethods that provide a computationally efficient alternative to the commonly\nused third-order method while retaining the convenient iterative property of\nthe latter. Finally, we demonstrate that almost no coding effort is needed to\nimplement the low-storage Lie group methods into existing gradient flow codes.",
        "positive": "Leading-order hadronic contributions to $g_\u03bc-2$: We present preliminary lattice results for the leading-order hadronic\ncontribution to the muon anomalous magnetic moment, calculated with HEX-smeared\nclover fermions. In our calculation we include 2+1-flavor ensembles with pions\nat the physical mass."
    },
    {
        "anchor": "Charmonium Spectrum from Quenched QCD with Overlap Fermions: We present the first study of the charmonium spectrum using overlap fermions,\non quenched configurations. Simulations are performed on $16^3 \\times 72$\nlattices, with Wilson gauge action at $\\beta$ = 6.3345. We demonstrate that we\nhave discretization errors under control at about 5%. We obtain 88(4) MeV for\nhyperfine splitting using the $r_0$ scale, and 121(6) MeV using the\n($1\\bar{P}-1\\bar{S}$) scale. This paper raises the possibility that the\ndiscrepancy between the lattice results and the experimental value for\ncharmonium hyperfine splitting can be resolved using overlap fermions to\nsimulate the charm quark on lattice.",
        "positive": "Scalar mesons and tetraquarks by means of lattice QCD: We study the light scalar mesons a_0(980) and kappa using N_f = 2+1+1 flavor\nlattice QCD. In order to probe the internal structure of these scalar mesons,\nand in particular to identify, whether a sizeable tetraquark component is\npresent, we use a large set of operators, including diquark-antidiquark,\nmesonic molecule and two-meson operators. The inclusion of disconnected\ndiagrams, which are technically rather challenging, but which would allow us to\nextend our work to e.g. the f_0(980) meson, is introduced and discussed."
    },
    {
        "anchor": "Nucleon isovector couplings from $N_f=2$ lattice QCD: We compute the axial, scalar, tensor and pseudoscalar isovector couplings of\nthe nucleon as well as the induced tensor and pseudoscalar charges in lattice\nsimulations with $N_f=2$ mass-degenerate non-perturbatively improved\nWilson-Sheikholeslami-Wohlert fermions. The simulations are carried out down to\na pion mass of 150 MeV and linear spatial lattice extents of up to 4.6 fm at\nthree different lattice spacings ranging from approximately 0.08 fm to 0.06 fm.\nPossible excited state contamination is carefully investigated and finite\nvolume effects are studied. The couplings, determined at these lattice\nspacings, are extrapolated to the physical pion mass. In this limit we find\nagreement with experimental results, where these exist, with the exception of\nthe magnetic moment. A proper continuum limit could not be performed, due to\nour limited range of lattice constants, but no significant lattice spacing\ndependence is detected. Upper limits on discretization effects are estimated\nand these dominate the error budget.",
        "positive": "Overcoming exponential volume scaling in quantum simulations of lattice\n  gauge theories: Real-time evolution of quantum field theories using classical computers\nrequires resources that scale exponentially with the number of lattice sites.\nBecause of a fundamentally different computational strategy, quantum computers\ncan in principle be used to perform detailed studies of these dynamics from\nfirst principles. Before performing such calculations, it is important to\nensure that the quantum algorithms used do not have a cost that scales\nexponentially with the volume. In these proceedings, we present an interesting\ntest case: a formulation of a compact U(1) gauge theory in 2+1 dimensions free\nof gauge redundancies. A naive implementation onto a quantum circuit has a gate\ncount that scales exponentially with the volume. We discuss how to break this\nexponential scaling by performing an operator redefinition that reduces the\nnon-locality of the Hamiltonian. While we study only one theory as a test case,\nit is possible that the exponential gate scaling will persist for formulations\nof other gauge theories, including non-Abelian theories in higher dimensions."
    },
    {
        "anchor": "Nucleon Momentum Fraction, Helicity and Transversity from 2+1-flavor\n  Lattice QCD: High statistics results for the isovector momentum fraction, $\\langle x\n\\rangle_{u-d}$, helicity moment, $\\langle x \\rangle_{\\Delta u-\\Delta d}$, and\nthe transversity moment, $\\langle x\\rangle_{\\delta u-\\delta d}$, of the nucleon\nare presented using seven ensembles of gauge configurations generated by the\nJLab/W&M/LANL/MIT collaborations using $2+1$-flavors of dynamical Wilson-clover\nquarks. Attention is given to understanding and controlling the contributions\nof excited states. The final results are obtained using a simultaneous fit in\nthe lattice spacing $a$, pion mass $M_\\pi$ and the finite volume parameter\n$M_\\pi L$ keeping leading order corrections. The data show no significant\ndependence on the lattice spacing and some evidence for finite-volume\ncorrections. The main variation is with $M_\\pi$, whose magnitude depends on the\nmass gap of the first excited state used in the analysis. Our final results, in\nthe $\\overline{\\rm MS}$ scheme at 2 GeV, are $\\langle x \\rangle_{u-d} =\n0.160(16)(20)$, $\\langle x \\rangle_{\\Delta u-\\Delta d} = 0.192(13)(20)$ and\n$\\langle x \\rangle_{\\delta u-\\delta d} = 0.215(17)(20)$, where the first error\nis the overall analysis uncertainty assuming excited-state contributions have\nbeen removed, and the second is an additional systematic uncertainty due to\npossible residual excited-state contributions. These results are consistent\nwith other recent lattice calculations and phenomenological global fit values.",
        "positive": "$\u039b(1405)$ from lattice QCD: Low-lying $\\Lambda$ baryons with spin 1/2 are analyzed in two-flavor lattice\nQCD. In order to extract two low-lying states for each parity, we construct $2\n\\times 2$ cross correlators from flavor SU(3) ``octet'' and ``singlet'' baryon\noperators, and diagonalize them. Two-flavor CP-PACS gauge configurations are\nemployed, which are generated with the renormalization-group improved gauge\naction and the ${\\mathcal O}(a)$-improved quark action. Simulation are\nperformed at three different $\\beta$'s, $\\beta = 1.80$, 1.95 and 2.10, whose\ncorresponding lattice spacings are $a = 0.2150$, 0.1555 and 0.1076 fm. For each\ncutoff, we adopt four different hopping parameters, ($\\kappa_{\\rm val},\n\\kappa_{\\rm sea}$). The corresponding pion masses range from about 500 MeV to\n1.1 GeV. The results are extrapolated to the physical quark-mass point. Our\nresults indicate that there are two negative-parity $\\Lambda$ states nearly\ndegenerate at around 1.6 GeV, whereas no state as low as $\\Lambda (1405)$ is\nobserved. By extracting the flavor components of each state, we find that the\nlowest (1st-excited) negative-parity state is dominated by flavor-singlet\n(flavor-octet) component."
    },
    {
        "anchor": "$Sp(2N)$ Yang-Mills theories on the lattice: scale setting and topology: We study Yang-Mills lattice theories with $Sp(N_c)$ gauge group, with\n$N_c=2N$, for $N=1,\\,\\cdots,\\,4$. We show that if we divide the renormalised\ncouplings appearing in the Wilson flow by the quadratic Casimir $C_2(F)$ of the\n$Sp(N_c)$ group, then the resulting quantities display a good agreement among\nall values of $N_c$ considered, over a finite interval in flow time. We use\nthis scaled version of the Wilson flow as a scale-setting procedure, compute\nthe topological susceptibility of the $Sp(N_c)$ theories, and extrapolate the\nresults to the continuum limit for each $N_c$.",
        "positive": "The lattice gluon propagator in Landau gauge at zero and finite\n  temperature: The interplay between the finite volume and finite lattice spacing is\ninvestigated using lattice QCD simulations to compute the Landau gauge gluon\npropagator at zero temperature. Comparing several ensembles with different\nlattice spacings and physical volumes, we conclude that the dominant effects,\nin the infrared region, are associated with the use of a finite lattice\nspacing. The simulations show that decreasing the lattice spacing, while\nkeeping the same physical volume, leads to an enhancement of the infrared gluon\npropagator. Moreover, we also present results for the Landau gauge gluon\npropagator at finite temperature."
    },
    {
        "anchor": "Flux tube profiles in two-color QCD at low temperature and high density: We investigate the temperature and density dependence of the color flux tube\nstructure of dense two-color QCD with $N_f = 2$ Wilson fermions by using a\nlattice simulation. From Refs. [1] and [2], we have already clarified the rich\nphase structure in the low temperature region, including the hadronic and\nsuperfluid phases. In this study we measure the quark-antiquark potential and\ncolor flux tube profiles in such a low temperature region and find that even in\nthe high density superfluid phase, the color electric field is squeezed into a\nflux tube as in the low density hadronic phase.",
        "positive": "Comment on \"Lattice Gluon and Ghost Propagators, and the Strong Coupling\n  in Pure $SU(3)$ Yang-Mills Theory: Finite Lattice Spacing and Volume Effects\": The authors of ref. Phys.Rev. D94 (2016) no.1, 014502 reported about a\ncareful analysis of the impact of lattice artifacts on the $SU(3)$ gauge-field\npropagators. In particular, they found that the low-momentum behavior of the\nrenormalized propagators depends on the lattice bare coupling and interpreted\nthis fact as the result of it being affected by finite lattice spacing\nartifacts. We do not share this interpretation and present here a different and\nmore suitable explanation for these results."
    },
    {
        "anchor": "Dynamics on the SU(2) fundamental domain: For SU(2) gauge theory on the three-sphere we focus on a subspace of modes of\nthe gauge field that contains the tunnelling paths and the sphalerons and on\nwhich the energy functional is degenerate to second order in the fields. The\nultimate goal is to study the $\\theta$-dependence of the low-lying states for\nthis model by imposing boundary conditions on the fundamental domain.",
        "positive": "Chiral Perturbation Theory for Staggered Sea Quarks and Ginsparg-Wilson\n  Valence Quarks: We study lattice QCD with staggered sea and Ginsparg-Wilson valence quarks.\nThe Symanzik effective action for this mixed lattice theory, including the\nlattice spacing contributions of O(a^2), is derived. Using this effective\ntheory we construct the leading order chiral Lagrangian. The masses and decay\nconstants of pseudoscalars containing two Ginsparg-Wilson valence quarks are\ncomputed at one loop order."
    },
    {
        "anchor": "Thermodynamics with Dynamical Clover Fermions: We investigate the finite temperature behavior of nonperturbatively improved\nclover fermions on lattices with temporal extent N_t=4 and 6. Unfortunately in\nthe gauge coupling range, where the clover coefficient has been determined\nnonperturbatively, the finite temperature crossover/transition occurs at heavy\npseudoscalar masses and large pseudoscalar to vector meson mass ratios.\nHowever, on an N_t=6 lattice the thermal crossover for the improved fermions is\nmuch smoother than for unimproved Wilson fermions and no strange metastable\nbehavior is observed.",
        "positive": "Perturbative renormalization of the electric field correlator: The momentum diffusion coefficient of a heavy quark in a hot QCD plasma can\nbe extracted as a transport coefficient related to the correlator of two\ncolour-electric fields dressing a Polyakov loop. We determine the perturbative\nrenormalization factor for a particular lattice discretization of this\ncorrelator within Wilson's SU(3) gauge theory, finding a ~12% NLO correction\nfor values of the bare coupling used in the current generation of simulations.\nThe impact of this result on existing lattice determinations is commented upon,\nand a possibility for non-perturbative renormalization through the gradient\nflow is pointed out."
    },
    {
        "anchor": "Photon mass term as an IR regularization for QCD+QED on the lattice: Inclusion of QED in lattice QCD calculations can lead to power-law volume\nartifacts as a consequence of the long-range nature of the interaction. Such\nartifacts must be removed by extrapolation in order to attain reliable infinite\nvolume estimates of observables and quantities derived from them. As an\nalternative to this methodology, we consider the use of a photon mass term as\nan infrared regulator for QCD+QED, and explore the viability of its use in\ndetermining hadron mass shifts and splittings.",
        "positive": "Thermodynamics of SU(3) gauge theory on anisotropic lattices: Finite temperature SU(3) gauge theory is studied on anisotropic lattices\nusing the standard plaquette gauge action. The equation of state is calculated\non $16^{3} \\times 8$, $20^{3} \\times 10$ and $24^{3} \\times 12$ lattices with\nthe anisotropy $\\xi \\equiv a_s / a_t = 2$, where $a_s$ and $a_t$ are the\nspatial and temporal lattice spacings. Unlike the case of the isotropic lattice\non which $N_t=4$ data deviate significantly from the leading scaling behavior,\nthe pressure and energy density on an anisotropic lattice are found to satisfy\nwell the leading $1/N_t^2$ scaling from our coarsest lattice, $N_t/\\xi=4$. With\nthree data points at $N_t/\\xi=4$, 5 and 6, we perform a well controlled\ncontinuum extrapolation of the equation of state. Our results in the continuum\nlimit agree with a previous result from isotropic lattices using the same\naction, but have smaller and more reliable errors."
    },
    {
        "anchor": "Flavored pions and kaons at next-to-leading order in mixed-action\n  staggered chiral perturbation theory: Different versions of improved staggered fermions can be used as valence\nquarks to reduce discretization effects in lattice QCD calculations while\nincreasing statistics on existing staggered gauge ensembles. Such mixed-action\nsimulations can be used to improve determinations of light quark masses,\nGasser-Leutwyler couplings, decay constants, and other parameters relevant to\nparticle phenomenology. We recall the generalization of ordinary, unmixed\nstaggered chiral perturbation theory required to describe data from lattice\ncalculations with a mixed action such as with HYP staggered valence quarks and\nasqtad sea quarks. We calculate the next-to-leading order loop diagrams\ncontributing to the masses and decay constants of the flavored pseudo-Goldstone\nbosons of all tastes and here report results for the decay constants and\nvalence-valence masses.",
        "positive": "The QCD thermal phase transition in the presence of a small chemical\n  potential: We propose a new method to investigate the thermal properties of QCD with a\nsmall quark chemical potential $\\mu$. Derivatives of the phase transition point\nwith respect to $\\mu$ are computed at $\\mu=0$ for 2 flavors of p-4 improved\nstaggered fermions with $ma=0.1,0.2$ on a $16^3\\times4$ lattice. The resulting\nTaylor expansion is well behaved for the small values of $\\mu_{\\rm\nq}/T_c\\sim0.1$ relevant for RHIC phenomenology, and predicts a critical curve\n$T_c(\\mu)$ in reasonable agreement with estimates obtained using exact\nreweighting. In addition, we contrast the case of isoscalar and isovector\nchemical potentials, quantify the effect of $\\mu\\not=0$ on the equation of\nstate, and comment on the complex phase of the fermion determinant in QCD with\n$\\mu\\not=0$."
    },
    {
        "anchor": "Multi-boson spectrum of the SU(2)-Higgs model: Lattice simulations are used to compute the spectrum of energy levels for all\nangular momentum and parity quantum numbers in the SU(2)-Higgs model, with\nparameters chosen to match experimental data from the Higgs-W boson sector of\nthe standard model. Creation operators are constructed for all lattice\nirreducible representations, and a correlation matrix is formed from which the\nspectrum is extracted using a variational analysis. Many multi-boson states are\nobserved and careful analysis reveals that all are consistent with\nweakly-interacting Higgs and W bosons.",
        "positive": "Latest Results from Heavy Quark Simulations: The status of b-bbar and c-cbar calculations, numerical and analytic, are\nreviewed. The extraction of alpha_s and quark masses from spectrum calculations\nis discussed. The NRQCD and Improved Heavy Wilson formulations of heavy quarks\nare compared, and recent calculations using a Heavy Staggered formulation are\ndiscussed."
    },
    {
        "anchor": "Machine-learning physics from unphysics: Finding deconfinement\n  temperature in lattice Yang-Mills theories from outside the scaling window: We study the machine learning techniques applied to the lattice gauge\ntheory's critical behavior, particularly to the confinement/deconfinement phase\ntransition in the SU(2) and SU(3) gauge theories. We find that the neural\nnetwork, trained on lattice configurations of gauge fields at an unphysical\nvalue of the lattice parameters as an input, builds up a gauge-invariant\nfunction, and finds correlations with the target observable that is valid in\nthe physical region of the parameter space. In particular, if the algorithm\naimed to predict the Polyakov loop as the deconfining order parameter, it\nbuilds a trace of the gauge group matrices along a closed loop in the time\ndirection. As a result, the neural network, trained at one unphysical value of\nthe lattice coupling $\\beta$ predicts the order parameter in the whole region\nof the $\\beta$ values with good precision. We thus demonstrate that the machine\nlearning techniques may be used as a numerical analog of the analytical\ncontinuation from easily accessible but physically uninteresting regions of the\ncoupling space to the interesting but potentially not accessible regions.",
        "positive": "High-precision scale setting in lattice QCD: Scale setting is of central importance in lattice QCD. It is required to\npredict dimensional quantities in physical units. Moreover, it determines the\nrelative lattice spacings of computations performed at different values of the\nbare coupling, and this is needed for extrapolating results into the continuum.\nThus, we calculate a new quantity, $w_0$, for setting the scale in lattice QCD,\nwhich is based on the Wilson flow like the scale $t_0$ (M. Luscher, JHEP 1008\n(2010) 071). It is cheap and straightforward to implement and compute. In\nparticular, it does not involve the delicate fitting of correlation functions\nat asymptotic times. It typically can be determined on the few per-mil level.\nWe compute its continuum extrapolated value in 2+1-flavor QCD for physical and\nnon-physical pion and kaon masses, to allow for mass-independent scale setting\neven away from the physical mass point. We demonstrate its robustness by\ncomputing it with two very different actions (one of them with staggered, the\nother with Wilson fermions) and by showing that the results agree for physical\nquark masses in the continuum limit."
    },
    {
        "anchor": "Gauge-fixing on the Lattice via Orbifolding: When fixing a covariant gauge, most popularly the Landau gauge, on the\nlattice one encounters the Neuberger 0/0 problem which prevents one from\nformulating a Becchi--Rouet--Stora--Tyutin symmetry on the lattice. Following\nthe interpretation of this problem in terms of Witten-type topological field\ntheory and using the recently developed Morse theory for orbifolds, we propose\na modification of the lattice Landau gauge via orbifolding of the gauge-fixing\ngroup manifold and show that this modification circumvents the orbit-dependence\nissue and hence can be a viable candidate for evading the Neuberger problem.\nUsing algebraic geometry, we also show that though the previously proposed\nmodification of the lattice Landau gauge via stereographic projection relies on\ndelicate departure from the standard Morse theory due to the non-compactness of\nthe underlying manifold, the corresponding gauge-fixing partition function\nturns out to be orbit independent for all the orbits except in a region of\nmeasure zero.",
        "positive": "MCRG study of 8 and 12 fundamental flavors: We study the renormalization group properties of SU(3) gauge theories with\nN_f=8 and 12 nearly-massless fermions, using Monte Carlo Renormalization Group\n(MCRG) two-lattice matching techniques to predict bare step-scaling functions\ns_b. Traditional MCRG two-lattice matching requires that the renormalization\nscheme be optimized for each bare lattice coupling, so that s_b is a composite\nof many different discrete beta functions. We propose an improved procedure\nthat uses the Wilson flow to eliminate the need for this optimization of the RG\nblocking transformation. While our 12-flavor results indicate an infrared fixed\npoint, s_b for N_f=8 is significantly different from zero until strong-coupling\nlattice artifacts obstruct two-lattice matching. Although both procedures\nproduce qualitatively similar bare step-scaling functions, the new s_b obtained\nby combining the Wilson flow with MCRG two-lattice matching have the distinct\nadvantage of corresponding to unique discrete beta functions."
    },
    {
        "anchor": "Two Flavour QCD Phase Transition: Results on the phase transition in QCD with two flavours of light staggered\nfermions from an ongoing simulation are presented. We find the restoration of\nthe chiral SU(2) x SU(2) symmetry, but not of the axial U_A(1) symmetry.",
        "positive": "Generalized Parton Distributions from Lattice QCD: I review the LHPC Collaboration's lattice QCD calculations of the generalized\nparton distributions of the nucleon and highlight those aspects of nucleon\nstructure best illuminated by lattice QCD, the nucleon's spin decomposition and\ntransverse quark structure."
    },
    {
        "anchor": "Four Fermion Operator Matching with NRQCD Heavy and AsqTad Light Quarks: We present one-loop matching coefficients between continuum and lattice QCD\nfor the heavy-light four-fermion operators relevant for neutral B meson mixing\nboth within and beyond the Standard Model. For the lattice theory we use\nnonrelativistic QCD (NRQCD) to describe b quarks and improved staggered\nfermions (AsqTad) for light quarks. The gauge action is the tree-level Symanzik\nimproved gauge action. Matching to full QCD is carried out through order\nalpha_s, Lambda_{QCD}/M_b, and alpha_s/(aM_b).",
        "positive": "New ideas for g-2 on the lattice: Using iso-spin symmetry the quark-connected and disconnected contributions to\nthe hadronic vacuum polarisation in a theory with N_f=2 flavours can be\ndescribed as independent correlation functions, respectively. We show how this\nallows to use twisted boundary conditions for the connected contribution in\norder to improve the q^2-resolution in lattice QCD. Furthermore we derive an\nexact relation between the connected and the disconnected contributions at NLO\nin chiral perturbation theory. We discuss extensions to theories with more than\n2 dynamical flavours."
    },
    {
        "anchor": "One-loop matching of improved four-fermion staggered operators with an\n  improved gluon action: We present results for one-loop matching factors of four-fermion operators\ncomposed of HYP-smeared staggered fermions. We generalize previous calculations\nby using the tree-level improved Symanzik gauge action. These results are\nneeded for our companion numerical calculation of $B_K$ and related matrix\nelements. We find that the impact on one-loop matching factors of using the\nimproved gluon action is much smaller than that from the use of either HYP\nsmearing or mean-field improvement. The one-loop coefficients for mean-field\nimproved, HYP-smeared operators with the Symanzik gauge action have a maximum\nmagnitude of $O(1)\\times \\alpha_s$, indicating that perturbation theory is\nreasonably convergent.",
        "positive": "Exploring the Spectrum of QCD using the Lattice: The calculation of the spectrum of QCD is key to an understanding of the\nstrong interactions, and vital if we are to capitalize on the experimental\nstudy of the spectrum. In this paper, we describe progress towards\nunderstanding the spectrum of resonances of both mesons and baryons from\nlattice QCD, focusing in particular on the resonances of the $I=1/2$ nucleon\nstates, and of charmonium mesons composed of the heavy charmed quarks."
    },
    {
        "anchor": "Spectroscopy of Hadrons with b Quarks from Lattice NRQCD: Preliminary results from an extensive lattice calculation of the B, B_c, and\n\\Upsilon spectrum at quenched \\beta = 6.0 are presented. The study includes\nradially and orbitally excited mesons, and baryons containing b quarks. The b\nquarks are formulated using NRQCD; for light and c quarks, a tadpole-improved\nclover action is used.",
        "positive": "Quantum field theories on the Lefschetz thimble: In these proceedings, we summarize the Lefschetz thimble approach to the sign\nproblem of Quantum Field Theories. In particular, we review its motivations,\nand we summarize the results of the application of two different algorithms to\ntwo test models."
    },
    {
        "anchor": "Matrix product states and the nonabelian rotor model: We use uniform matrix product states (MPS) to study the (1+1)D $O(2)$ and\n$O(4)$ rotor models, which are equivalent to the Kogut-Susskind formulation of\nmatter-free nonabelian lattice gauge theory on a \"hawaiian earring\" graph for\n$U(1)$ and $SU(2)$, respectively. Applying tangent space methods to obtain\nground states and determine the mass gap and the $\\beta$ function, we find\nexcellent agreement with known results, locating the BKT transition for $O(2)$\nand successfully entering the asymptotic weak-coupling regime for $O(4)$. To\nobtain a finite local Hilbert space, we truncate in the space of generalized\nFourier modes of the gauge group, comparing the effects of different cutoff\nvalues. We find that higher modes become important in the crossover and\nweak-coupling regimes of the nonabelian theory, where entanglement also\nsuddenly increases. This could have important consequences for TNS studies of\nYang-Mills on higher dimensional graphs.",
        "positive": "Confinement and the photon propagator in 3D compact QED: a lattice study\n  in Landau gauge at zero and finite temperature: On the lattice we study the gauge boson propagator of three dimensional\ncompact QED in Landau gauge at zero and non-zero temperature. The\nnon-perturbative effects are taken into account by the generation of a mass, by\nan anomalous dimension and by the photon wave function renormalization. All\nthese effects can be attributed to the monopoles: they are absent in the\npropagator of the singularity-free part of the gauge field. We assess carefully\nthe Gribov copy problem for the propagator and the parameters emerging from the\nfits."
    },
    {
        "anchor": "Calculating the two-pion decay and mixing of neutral K mesons: The recent calculation of the complex isospin-two decay amplitude A_2 with\nphysical kinematics is presented together with exploratory calculations of the\nisospin-zero decay amplitude A_0. Prospects for accurate calculation of A_0 as\nwell as the mass difference between the K_L and K_S mesons are discussed.",
        "positive": "The Aoki phase revisited: In order to elucidate the vacuum structure of the Aoki phase, we carried out\na numerical investigation of QCD with two flavours of Wilson fermions, within\nthe p.d.f. framework and in the absence of external sources. The simulations\nperformed at V = 44 suggest a rich vacuum structure, where the observable\n$i\\bar\\psi\\gamma_5\\psi$ is allowed to take non-zero values of the same order of\nmagnitude than the order parameter of the Aoki phase\n$i\\bar\\psi\\gamma_5\\tau_3\\psi$. However, the simulation at higher volumes V =\n6^4 suffers from large statistical errors."
    },
    {
        "anchor": "Topological defects and confinement with machine learning: the case of\n  monopoles in compact electrodynamics: We investigate the advantages of machine learning techniques to recognize the\ndynamics of topological objects in quantum field theories. We consider the\ncompact U(1) gauge theory in three spacetime dimensions as the simplest example\nof a theory that exhibits confinement and mass gap phenomena generated by\nmonopoles. We train a neural network with a generated set of monopole\nconfigurations to distinguish between confinement and deconfinement phases,\nfrom which it is possible to determine the deconfinement transition point and\nto predict several observables. The model uses a supervised learning approach\nand treats the monopole configurations as three-dimensional images (holograms).\nWe show that the model can determine the transition temperature with accuracy,\nwhich depends on the criteria implemented in the algorithm. More importantly,\nwe train the neural network with configurations from a single lattice size\nbefore making predictions for configurations from other lattice sizes, from\nwhich a reliable estimation of the critical temperatures are obtained.",
        "positive": "Variational study of the flux tube recombination in the two quarks and\n  two quarks system in Lattice QCD: The color fields in a system composed by two static quarks and two static\nantiquarks are studied. In particular, we consider the four particles in the\ncorners of a rectangle, and two possible alignment of the particles, one in\nwhich the quarks are at the same side of the rectangle, and the other where\nthey are at opposite sides. We use a variational method, to probe not only the\nground state but also the first excited state. This results permit us to\nobserve and interpret the flux-tube recombination in the mesons to mesons and\nthe tetraquark to mesons transitions, for both states. The results are compared\nwith previous results for the static potential and the Casimir scaling\npredictions."
    },
    {
        "anchor": "On O($a^2$) effects in gradient flow observables: In lattice gauge theories, the gradient flow has been used extensively both,\nfor scale setting and for defining finite volume renormalization schemes for\nthe gauge coupling. Unfortunately, rather large cutoff effects have been\nobserved in some cases. We here investigate these effects to leading order in\nperturbation theory, considering various definitions of the lattice observable,\nthe lattice flow equation and the Yang Mills lattice action. These\nconsiderations suggest an improved set- up for which we perform a scaling test\nin the pure SU(3) gauge theory, demonstrating strongly reduced cutoff effects.\nWe then attempt to obtain a more complete understanding of the structure of\nO($a^2$) effects by applying Symanzik's effective theory approach to the 4+1\ndimensional local field theory with flow time as the fifth dimension. From\nthese considerations we are led to a fully O($a^2$) improved set-up the study\nof which is left to future work.",
        "positive": "Fourier coefficients of the net-baryon number density: We calculate Fourier coefficients of the net-baryon number as a function of a\npurely imaginary chemical potential. The asymptotic behavior of these\ncoefficients is governed by the singularity structure of the QCD partition\nfunction and thus encodes information on phase transitions. For the calculation\nof the Fourier coefficients from lattice data of the Bielefeld-Parma\ncollaboration we use a novel Filon-type quadrature, designed for highly\noscillatory integrals. We find sensitivity to chiral scaling in a narrow\ntemperature interval below the Roberge-Weiss transition temperature. Scaling\nfits yield reasonable values for the position of the Lee-Yang edge singularity\nin the complex chemical potential plane. Our lattice data has been obtained\nfrom simulations with (2+1)-flavors of highly improved staggered quarks (HISQ)\nat imaginary chemical potential on $N_\\tau=4, 6$ and $8$ lattices at physical\nquark masses."
    },
    {
        "anchor": "$\\overline{B}\\rightarrow D^\\ast\\ell\\overline\u03bd$ at non-zero recoil: We present preliminary results from our analysis of the form factors for the\n$\\overline{B}\\rightarrow D^\\ast\\ell\\overline{\\nu}$ decay at non-zero recoil.\nOur analysis includes 15 MILC asqtad ensembles with $N_f=2+1$ flavors of sea\nquarks and lattice spacings ranging from $a\\approx 0.15$ fm down to $0.045$ fm.\nThe valence light quarks employ the asqtad action, whereas the heavy quarks are\ntreated using the Fermilab action. We conclude with a discussion of future\nplans and phenomenological implications. When combined with experimental\nmeasurements of the decay rate, our calculation will enable a determination of\nthe CKM matrix element $|V_{cb}|$.",
        "positive": "Twisted lattice supersymmetry and applications to AdS/CFT: I review recent approaches to constructing supersymmetric lattice theories\nfocusing in particular on the concept of topological twisting. The latter\ntechnique is shown to expose a nilpotent, scalar supersymmetry which can be\nimplemented exactly in the lattice theory. Using these ideas a lattice action\nfor $\\mathcal{N}=4$ super Yang-Mills in four dimensions can be written down\nwhich is gauge invariant, free of fermion doublers and respects one out of a\ntotal of 16 continuum supersymmetries. It is shown how these exact symmetries\ntogether with the large point group symmetry of the lattice strongly constrain\nthe possible counterterms needed to renormalize the theory and hence determine\nhow much residual fine tuning will be needed to restore all supersymmetries in\nthe continuum limit. We report on progress to study these renormalization\neffects at one loop. We go on to give examples of applications of these\nsupersymmetric lattice theories to explore the connections between gauge\ntheories and gravity."
    },
    {
        "anchor": "A new method for computation of QCD thermodynamics: EOS, specific heat\n  and speed of sound: We propose a new variant of the operator method for the computation of the\nequation of state of QCD, which yields positive pressure for all temperatures\nand all values of temporal lattice spacings. Using this new method, we\ncalculate the continuum limit of pressure, energy density, entropy density,\nspecific heat, and the speed of sound, in quenched QCD, for 0.9 \\le T/T_c \\le\n3.",
        "positive": "First results on the running coupling in QCD with two massless flavours: We report on the non-perturbative computation of the running coupling of\ntwo-flavour QCD in the Schr\"odinger functional scheme. The corresponding\nLambda-parameter, which describes the coupling strength at high energy, is\nrelated to a low energy scale which still remains to be connected to a hadronic\n``experimentally'' observable quantity. We find the non-perturbative evolution\nof the coupling indispensable to avoid untolerable errors in the estimated\nLambda-parameter."
    },
    {
        "anchor": "Monopoles and Vortices in the SU(2) Positive Plaquette Model: We study the heavy quark potential in the SU(2) positive plaquette model\nusing monopoles in the maximum abelian gauge, and vortices. Monopoles give a\nquantitative description of the string tension. Vortices approximately\nreproduce the entire heavy quark potential.",
        "positive": "On the Weak Coupling Limit for Massive Yang-Mills: For small values of the gauge coupling constant, we compare the densities of\nthe energy of the vacuum and of the order parameter, evaluated in the lattice\nMonte Carlo simulation and in the perturbative field theory at two loop\n(Minkowski). The continuum calculation allows a very good fit of the simulation\nresults, away from the phase transition line. This confirms the conjecture that\nthe lattice provides a regularization of the (nonrenormalizable) massive\nYang-Mills and moreover it shows the physical meaning of the parameters used in\nthe simulation."
    },
    {
        "anchor": "Observing dynamical SUSY breaking with lattice simulation: On the basis of the recently developed lattice formulation of supersymmetric\ntheories which keeps a part of the supersymmetry, we propose a method of\nobserving dynamical SUSY breaking with lattice simulation. We use Hamiltonian\nas an order parameter and measure the ground state energy as a zero temperature\nlimit of the finite temperature simulation. Our method provides a way of\nobtaining a physical result from the lattice simulation for supersymmetric\ntheories.",
        "positive": "High-Temperature series for the $RP^{n-1}$ lattice spin model\n  (generalized Maier-Saupe model of nematic liquid crystals) in two space\n  dimensions and with general spin dimensionality n: High temperature series expansions of the spin-spin correlation functions of\nthe RP^{n-1} spin model on the square lattice are computed through order\nbeta^{8} for general spin dimensionality n. Tables are reported for the\nexpansion coefficients of the energy per site, the susceptibility and the\nsecond correlation moment."
    },
    {
        "anchor": "Chiral properties of domain wall fermions with improved gauge actions: We study the chiral properties of quenched domain wall fermions with several\ngauge actions. We demonstrate that the nearly translationally invariant modes\nin the fifth dimension that dominate the residual mass for Wilson gauge action\ncan be substantially suppressed using improved gauge actions. In particular, we\nstudy the Symanzik action, the Iwasaki action, the DBW2 action and compare them\nto the Wilson action.",
        "positive": "Charmonium spectroscopy and mixing with light quark and open charm\n  states from nF=2 lattice QCD: We study the charmonium spectrum including higher spin and gluonic\nexcitations. We determine an upper limit on the mixing of the eta_c ground\nstate with light pseudoscalar flavour-singlet mesons and investigate the mixing\nof charmonia near open charm thresholds with pairs of (excited) D and anti-D\nmesons. For charm and light valence quarks and nF=2 sea quarks, we employ the\nnon-perturbatively improved Sheikholeslami-Wohlert (clover) action. Excited\nstates are accessed using the variational technique, starting from a basis of\nsuitably optimised operators. For some aspects of this study, the use of\nimproved stochastic all-to-all propagators was essential."
    },
    {
        "anchor": "Momentum dependence of the topological susceptibility with overlap\n  fermions: Knowledge of the derivative of the topological susceptibility at zero\nmomentum is important for assessing the validity of the Witten-Veneziano\nformula for the eta' mass, and likewise for the resolution of the EMC proton\nspin problem. We investigate the momentum dependence of the topological\nsusceptibility and its derivative at zero momentum using overlap fermions in\nquenched lattice QCD simulations. We expose the role of the low-lying Dirac\neigenmodes for the topological charge density, and find a negative value for\nthe derivative. While the sign of the derivative is consistent with the QCD sum\nrule for pure Yang-Mills theory, the absolute value is overestimated if the\ncontribution from higher eigenmodes is ignored.",
        "positive": "The pion-nucleon sigma term with $N_f=2+1$ $\\mathcal{O}(a)$-improved\n  Wilson fermions: We present an analysis of the pion-nucleon sigma term on the CLS ensembles\nwith $N_f=2+1$ flavors of $\\mathcal{O}(a)$-improved Wilson fermions. We perform\na chiral interpolation based on ensembles with pion masses ranging from 130 MeV\nto roughly 350 MeV. The analysis covers four lattice spacings between $a\\approx\n[0.05 \\, \\rm{fm}\\ldots 0.09\\, \\rm{fm}]$, allowing for an estimate of\nsystematics associated with lattice artefacts."
    },
    {
        "anchor": "Two-Dimensional 8-State Potts Model on Random Lattices: A Monte Carlo\n  Study: We use two-dimensional Poissonian random lattices of Voronoi/ Delaunay type\nto study the effect of quenched coordination number randomness on the nature of\nthe phase transition in the eight-state Potts model, which is of first order on\nregular lattices. From extensive Monte Carlo simulations we obtain strong\nevidence that the phase transition remains first order for this type of\nquenched randomness. Our result is in striking contrast to a recent Monte Carlo\nstudy of quenched bond randomness for which the order of the phase transition\nchanges from first to second order.",
        "positive": "Pseudoscalar Vertex, Goldstone Boson and Quark Masses on the Lattice: We analyse the Structure Function collaboration data on the quark\npseudoscalar vertex and extract the Goldstone boson pole contribution, in 1/p2.\nThe strength of the pole is found to be quite large at presently accessible\nscales. We draw the important consequences of this finding for the various\ndefinitions of quark masses, and point out potential problems with the operator\nproduct expansion."
    },
    {
        "anchor": "Standard Model parameters and heavy quarks on the lattice: I review recent progresses in heavy quarks physics on the lattice. I focus on\ndecay constants and form factors relevant for the extraction of CKM matrix\nelements from experimental data. B-\\bar{B} mixing is also discussed. In the\nlast part of the paper I describe phenomenological applications of Heavy Quark\nEffective Theory (HQET) on the lattice, presenting in some detail the recent\nnon-perturbative determination of the b-quark mass including O(1/m_b)\ncorrections.",
        "positive": "QCD at finite density: Developments in QCD at finite density are reviewed. I begin by discussing\nsome new algorithms which have been applied to other theories with sign\nproblems. Then I discuss the method of analytic continuation in QCD using a\nseries expansion and review some of the results obtained using this method. By\nnow there are several different simulations using the method, and together they\ngive estimates of the systematic lattice effects, which turn out to be\ncontrolled. Finally I discuss a direct comparison of some of these lattice\npredictions with new experimental data which results in a very pleasant\nagreement."
    },
    {
        "anchor": "Critical Slowing-Down in $SU(2)$ Landau Gauge-Fixing Algorithms: We study the problem of critical slowing-down for gauge-fixing algorithms\n(Landau gauge) in $SU(2)$ lattice gauge theory on a $2$-dimensional lattice. We\nconsider five such algorithms, and lattice sizes ranging from $8^{2}$ to\n$36^{2}$ (up to $64^2$ in the case of Fourier acceleration). We measure four\ndifferent observables and we find that for each given algorithm they all have\nthe same relaxation time within error bars. We obtain that: the so-called {\\em\nLos Alamos} method has dynamic critical exponent $z \\approx 2$, the {\\em\noverrelaxation} method and the {\\em stochastic overrelaxation} method have $z\n\\approx 1$, the so-called {\\em Cornell} method has $z$ slightly smaller than\n$1$ and the {\\em Fourier acceleration} method completely eliminates critical\nslowing-down. A detailed discussion and analysis of the tuning of these\nalgorithms is also presented.",
        "positive": "Feynman gauge on the lattice: new results and perspectives: We have recently introduced a new implementation of the Feynman gauge on the\nlattice, based on a minimizing functional that extends in a natural way the\nLandau-gauge case, while preserving all the properties of the continuum\nformulation. The only remaining difficulty with our approach is that, using the\nstandard (compact) discretization, the gluon field is bounded, while its\nfour-divergence satisfies a Gaussian distribution, i.e. it is unbounded. This\ncan give rise to convergence problems when a numerical implementation is\nattempted. In order to overcome this problem, one can use different\ndiscretizations for the gluon field, or consider an SU(N_c) group with\nsufficiently large N_c. Here we discuss these two possible solutions."
    },
    {
        "anchor": "Many faces of the Landau gauge gluon propagator at zero and finite\n  temperature: positivity violation, spectral density and mass scales: We address several aspects of gluon propagation at zero and finite\ntemperature. In particular, we study the violation of spectral positivity, we\ndiscuss a method to extract the K\\\"all\\'{e}n-Lehmann spectral density of a\nparticle (be it elementary or bound state) propagator and apply it to compute\ngluon spectral densities from lattice data. Furthermore, we also consider the\ninterpretation of the Landau gauge gluon propagator at finite temperature as a\nmassive type bosonic propagator.",
        "positive": "Light meson electromagnetic form factors from three-flavor lattice QCD\n  with exact chiral symmetry: We study the chiral behavior of the electromagnetic (EM) form factors of pion\nand kaon in three-flavor lattice QCD. In order to make a direct comparison of\nthe lattice data with chiral perturbation theory (ChPT), we employ the overlap\nquark action that has exact chiral symmetry. Gauge ensembles are generated at a\nlattice spacing of 0.11 fm with four pion masses ranging between M_pi \\simeq\n290 MeV and 540 MeV and with a strange quark mass m_s close to its physical\nvalue. We utilize the all-to-all quark propagator technique to calculate the EM\nform factors with high precision. Their dependence on m_s and on the momentum\ntransfer is studied by using the reweighting technique and the twisted boundary\nconditions for the quark fields, respectively. A detailed comparison with SU(2)\nand SU(3) ChPT reveals that the next-to-next-to-leading order terms in the\nchiral expansion are important to describe the chiral behavior of the form\nfactors in the pion mass range studied in this work. We estimate the relevant\nlow-energy constants and the charge radii, and find reasonable agreement with\nphenomenological and experimental results."
    },
    {
        "anchor": "The Light Hadron Mass Spectrum with Non-Perturbatively O(a) Improved\n  Wilson Fermions: We compute the light hadron mass spectrum in quenched lattice QCD at $\\beta =\n6.0$ using the Sheikholeslami-Wohlert fermionic action. The calculation is done\nfor several choices of the coefficient $c_{SW}$, including $c_{SW} = 0$ and the\nrecently proposed optimal value $c_{SW} = 1.769$. We find that the individual\nmasses change by up to 30\\% under $O(a)$ improvement. The spectrum calculation\nsuggests $c_{SW} \\approx 1.4$ for the optimal value of the coefficient.",
        "positive": "Perturbative and non-perturbative renormalization results of the\n  Chromomagnetic Operator on the Lattice: The Chromomagnetic operator (CMO) mixes with a large number of operators\nunder renormalization. We identify which operators can mix with the CMO, at the\nquantum level. Even in dimensional regularization (DR), which has the simplest\nmixing pattern, the CMO mixes with a total of 9 other operators, forming a\nbasis of dimension-five, Lorentz scalar operators with the same flavor content\nas the CMO. Among them, there are also gauge noninvariant operators; these are\nBRST invariant and vanish by the equations of motion, as required by\nrenormalization theory. On the other hand using a lattice regularization\nfurther operators with $d \\leq 5$ will mix; choosing the lattice action in a\nmanner as to preserve certain discrete symmetries, a minimul set of 3\nadditional operators (all with $d<5$) will appear. In order to compute all\nrelevant mixing coefficients, we calculate the quark-antiquark (2-pt) and the\nquark-antiquark-gluon (3-pt) Green's functions of the CMO at nonzero quark\nmasses. These calculations were performed in the continuum (dimensional\nregularization) and on the lattice using the maximally twisted mass fermion\naction and the Symanzik improved gluon action. In parallel, non-perturbative\nmeasurements of the $K-\\pi$ matrix element are being performed in simulations\nwith 4 dynamical ($N_f = 2+1+1$) twisted mass fermions and the Iwasaki improved\ngluon action."
    },
    {
        "anchor": "An Algorithmic Approach to Quantum Field Theory: The lattice formulation provides a way to regularize, define and compute the\nPath Integral in a Quantum Field Theory. In this paper we review the\ntheoretical foundations and the most basic algorithms required to implement a\ntypical lattice computation, including the Metropolis, the Gibbs sampling, the\nMinimal Residual, and the Stabilized Biconjugate inverters. The main emphasis\nis on gauge theories with fermions such as QCD. We also provide examples of\ntypical results from lattice QCD computations for quantities of\nphenomenological interest.",
        "positive": "Parton distribution functions of $\u0394^+$ on the lattice: We perform a first calculation for the unpolarized parton distribution\nfunction of the $\\Delta^+$ baryon using lattice QCD simulations within the\nframework of Large Momentum Effective Theory. Two ensembles of $N_f=2+1+1$\ntwisted mass fermions are utilized with a pion mass of 270 MeV and 360 MeV,\nrespectively. The baryon, which is treated as a stable single-particle state,\nis boosted with momentum $P_3$ with values $\\{0.42,0.83,1.25\\}$ GeV, and we\nutilize momentum smearing to improve the signal. The unpolarized parton\ndistribution function of $\\Delta^+$ is obtained using a non-perturbative\nrenormalization and a one-loop formula for the matching, with encouraging\nprecision. In particular, we compute the $\\overline{d}(x)-\\overline{u}(x)$\nasymmetry and compare it with the same quantity in the nucleon, in a first\nattempt towards resolving the physical mechanism responsible for generating\nsuch asymmetry."
    },
    {
        "anchor": "The Emergence of a Heavy Quark Family on a Lattice: Within the framework of the ``Rome approach'' for a lattice chiral gauge\ntheory, the four-quark interaction with flavour symmetry is included. We\nanalyse spontaneous symmetry breaking and compute composite modes and their\ncontributions to the ground state energy. As a result, it is shown that the\nemergence of a heavy quark family is the energetically favoured solution.",
        "positive": "Spontaneous CP violation and quark mass ambiguities: I explore the regions of quark masses where CP will be spontaneously broken\nin the strong interactions. The boundaries of these regions are controlled by\nthe chiral anomaly, which manifests itself in ambiguities in the definition of\nnon-degenerate quark masses. In particular, the concept of a single massless\nquark is ill defined."
    },
    {
        "anchor": "Gauge-gravity duality -- Super Yang Mills Quantum Mechanics: We describe the conjectured holographic duality between Yang-Mills quantum\nmechanics and type IIa string theory. This duality allows us to use lattice\nMonte Carlo simulations to probe the physics of the gravitational theory - for\nexample, at low energies it provides a computation of black hole entropy in\nterms of a sum over microstates of the dual gauge theory. Numerical results are\npresented of the 4 supercharge theory at finite temperature",
        "positive": "Complex Langevin study of spontaneous symmetry breaking in IKKT matrix\n  model: The IKKT matrix model, in the large-$N$ limit, is conjectured to be a\nnon-perturbative definition of the ten-dimensional type IIB superstring theory.\nIn this work, we investigate the possibility of spontaneous breaking of the\nten-dimensional rotational symmetry in the Euclidean IKKT model. Since the\neffective action, after integrating out the fermions, is inherently complex, we\nuse the complex Langevin dynamics to study the model. In order to evade the\nsingular-drift problem in the model, we add supersymmetry preserving\ndeformations and then take the vanishing limit of the deformations. Our\nanalysis suggests that the phase of the Pfaffian indeed induces the spontaneous\nSO(10) symmetry breaking in the Euclidean IKKT model."
    },
    {
        "anchor": "Strange matrix elements of the nucleon: Results for the disconnected contributions to matrix elements of the vector\ncurrent and scalar density have been obtained for the nucleon from the Wilson\naction at beta=6 using a stochastic estimator technique and 2000 quenched\nconfigurations. Various methods for analysis are employed and chiral\nextrapolations are discussed.",
        "positive": "Duality in generalized Ising models: This paper rests to a large extend on a paper I wrote some time ago on\n'Duality in generalized Ising models and phase transitions without local order\nparameter'. It deals with Ising models with interactions containing products of\nmore than two spins. In contrast to the old paper I will first give examples\nbefore I come to the general statements. Of particular interest is a gauge\ninvariant Ising model in four dimensions. It has important properties in common\nwith models for quantum chromodynamics as developed by Ken Wilson. One phase\nyields an area law for the Wilson-loop yielding an interaction increasing\nproportional to the distance and thus corresponding to quark-confinement. The\nother phase yields a perimeter law allowing for a quark-gluon plasma."
    },
    {
        "anchor": "Kaon B parameter from quenched Lattice QCD: We present results of a large-scale simulation for the Kaon B parameter $B_K$\nin quenched lattice QCD with the Kogut-Susskind quark action. Calculating $B_K$\nat 1% statistical accuracy for seven values of lattice spacing in the range\n$a\\approx 0.24-0.04$ fm on lattices up to $56^3\\times 96$, we verify a\nquadratic $a$ dependence of $B_K$ theoretically predicted. Strong indications\nare found that, with our level of accuracy, $\\alpha_{\\bar{MS}}(1/a)^2$ terms\narising from our one-loop matching procedure have to be included in the\ncontinuum extrapolation. We present $B_K$(NDR, 2 GeV)=0.628(42) as our final\nvalue, as obtained by a fit including the $\\alpha_{\\bar{MS}}(1/a)^2$ term.",
        "positive": "Pathologies of Quenched Lattice QCD at non--zero Density and its\n  Effective Potential: We simulate lattice QCD at non--zero baryon density and zero temperature in\nthe quenched approximation, both in the scaling region and in the infinite\ncoupling limit. We investigate the nature of the forbidden region -- the range\nof chemical potential where the simulations grow prohibitively expensive, and\nthe results, when available, are puzzling if not unphysical. At weak coupling\nwe have explored the sensitivity of these pathologies to the lattice size, and\nfound that using a large lattice ($64 \\times 16^3$) does not remove them. The\neffective potential sheds considerable light on the problems in the\nsimulations, and gives a clear interpretation of the forbidden region. The\nstrong coupling simulations were particularly illuminating on this point."
    },
    {
        "anchor": "Nonassociative Algebras and Nonperturbative Field Theory for\n  Hierarchical Models: Hierarchical renormalization group (RG) transformations are related to\nnonassociative algebras. These algebras serve as a new basic tool for a\nrigorous treatment of global RG flows and the search of nontrivial infrared\nfixed points. Convergent expansion methods are presented and analyzed in terms\nof algebra norms. It is shown that the infrared fixed points are solutions of a\nquadratic equation with an infinite number of unknowns. A continuous manifold\nof two dimensional periodic nontrivial fixed points is presented in terms of\ntheta functions. Local Borel summability of the $\\epsilon$- expansion for\nn-well fixed points is proved by algebraic methods.",
        "positive": "On the gauge boson's properties in a candidate technicolor theory: The technicolor scenario replaces the Higgs sector of the standard model with\na strongly interacting sector. One candidate for a realization of such a sector\nis two-technicolor Yang-Mills theory coupled to two degenerate flavors of\nadjoint, massless techniquarks. Using lattice gauge theory the properties of\nthe technigluons in this scenario are investigated as a function of the\ntechniquark mass towards the massless limit. For that purpose the minimal\nLandau gauge two-point and three-point correlation functions are determined,\nincluding a detailed systematic error analysis. The results are, within the\nrelatively large systematic uncertainties, compatible with a behavior very\nsimilar to QCD at finite techniquark mass. However, the limit of massless\ntechniquarks exhibits features which could be compatible with a\n(quasi-)conformal behavior."
    },
    {
        "anchor": "Comparing the vacuum structure of quenched and dynamical configurations: We systematically compare filtering methods used to extract topological\nstructures on SU(3) lattice configurations. We show that there is a strong\ncorrelation of the topological charge densities obtained by APE and Stout\nsmearing. To get rid of artifacts of these methods, we analyze structures that\nare also seen by Laplace filtering. This combined analysis shows that the\ntopological charge density is more fragmented in the presence of dynamical\nquarks.",
        "positive": "Heavy quark momentum diffusion from the lattice using gradient flow: We apply the gradient flow on a color-electric two-point function that\nencodes the heavy quark momentum diffusion coefficient. The simulations are\ndone on fine isotropic lattices in the quenched approximation at $1.5\\,T_c$.\nThe continuum extrapolation is performed at fixed flow time followed by a\nsecond extrapolation to zero flow time. Perturbative calculations of this\ncorrelation function under Wilson flow are used to enhance the extrapolations\nof the non-perturbative lattice correlator. The final estimate for the\ncontinuum correlator at zero flow time largely agrees with one obtained from a\nprevious study using the multi-level algorithm. We perform a spectral\nreconstruction based on perturbative model fits to estimate the heavy quark\nmomentum diffusion coefficient. The approach we present here yields\nhigh-precision data for the correlator and is also applicable for actions with\ndynamical fermions."
    },
    {
        "anchor": "Upper and lower Higgs boson mass bounds from a lattice Higgs-Yukawa\n  model with dynamical overlap fermions: We study a lattice Higgs-Yukawa model emulating the same Higgs-fermion\ncoupling structure as in the Higgs sector of the electroweak Standard Model, in\nparticular, obeying a Ginsparg-Wilson version of the underlying SU(2) x U(1)\nsymmetry, being a global symmetry here due to the neglection of gauge fields in\nthis model. In this paper we present our results on the cutoff-dependent upper\nHiggs boson mass bound at several selected values of the cutoff parameter.",
        "positive": "Improved performance of QCD code on ALiCE: We present results for the performance of QCD code on ALiCE, the Alpha-Linux\nCluster Engine at Wuppertal. We describe the techniques employed to optimise\nthe code, including the metaprogramming of assembler kernels, the effects of\ndata layout and an investigation into the overheads incurred by the\ncommunication."
    },
    {
        "anchor": "Cascade Baryon Spectrum from Lattice QCD: A comprehensive study of the cascade baryon spectrum using lattice QCD\naffords the prospect of predicting the masses of states not yet discovered\nexperimentally, and determining the spin and parity of those states for which\nthe quantum numbers are not yet known. The study of the cascades, containing\ntwo strange quarks, is particularly attractive for lattice QCD in that the\nchiral effects are reduced compared to states composed only of u/d quarks, and\nthe states are typically narrow. We report preliminary results for the cascade\nspectrum obtained by using anisotropic N_f = 2 Wilson lattices with temporal\nlattice spacing inverse 5.56 GeV.",
        "positive": "Sigma terms and strangeness content of the nucleon with $N_f=2+1+1$\n  twisted mass fermions: We study the nucleon matrix elements of the quark scalar-density operator\nusing maximally twisted mass fermions with dynamical light ($u$,$d$), strange\nand charm degrees of freedom. We demonstrate that in this setup the nucleon\nmatrix elements of the light and strange quark densities can be obtained with\ngood statistical accuracy, while for the charm quark counterpart only a bound\ncan be provided. The present calculation which is performed at only one value\nof the lattice spacing and pion mass serves as a benchmark for a future more\nsystematic computation of the scalar quark content of the nucleon."
    },
    {
        "anchor": "Precision test of the gauge/gravity duality in two-dimensional N=(8,8)\n  SYM: The $\\epsilon - p$ is calculated from lattice simulations of two dimensional\n${\\cal N}=(8,8)$ $SU(N)$ SYM to test the gauge gravity duality. We employ the\nSugino action with keeping two of sixteen supercharges exactly on the lattice.\nThe thermodynamics of this gauge theory is described by the black 1-branes at\nlow temperature. The internal energy density $\\epsilon$ and the pressure $p$\ncan be analytically estimated in the gravitational theory. The lattice results\nin $N=12$ show that $\\epsilon - p$ of the thermal SYM reproduces the prediction\nof the gravitational theory for the dimensionless temperature $T_{\\rm\neff}<0.4$. This clearly indicates that the duality is valid in this system.",
        "positive": "Abelian spatial string tension in finite temperature SU(2) gauge theory: We investigate Abelian and monopole contributions to spatial string tension\nin the deconfined phase of finite temperature SU(2) gauge theory without\nimposing any gauge fixing conditions. Lattice calculations of non-Abelian and\nAbelian spatial string tensions from the Wilson action at gauge coupling\n$\\beta=2.74$ and lattice volume $24^3\\times{N_t}$ $(N_{t}=\\left\\{\n24,8,6,4,2)\\right\\}$ show that these string tensions agree with each other\nwithin error bars at any adopted value of $N_t$, which implies Abelian\ndominance. From measurements of non-Abelian, Abelian, and monopole forces that\narise from the corresponding spatial string tension, furthermore, we find the\ntendency that the monopole contribution to the spatial string tension can be\nalmost as large as the non-Abelian and Abelian ones. The temperature dependence\nof the calculated non-Abelian and Abelian spatial string tensions allows us to\nconclude that the concept of dimensional reduction holds both for non-Abelian\nand Abelian sectors at temperatures higher than twice the critical temperature."
    },
    {
        "anchor": "Non-perturbative determination of improvement $b$-coefficients in\n  $N_f=3$: We present our preliminary results of the non-perturbative determination of\nthe valence mass dependent coefficients $b_\\mathrm{A}-b_\\mathrm{P}$ and\n$b_\\mathrm{m}$ as well as the ratio $Z_\\mathrm{P} Z_\\mathrm{m}/ Z_\\mathrm{A}$\nentering the flavour non-singlet PCAC relation in lattice QCD with $N_f=3$\ndynamical flavours. We apply the method proposed in the past for quenched\napproximation and $N_f=2$ cases, employing a set of finite-volume ALPHA\nconfigurations with Schr\\\"odinger functional boundary conditions, generated\nwith $O(a)$ improved Wilson fermions and the tree-level Symanzik-improved gauge\naction for a range of couplings relevant for simulations at lattice spacings of\nabout $0.09 \\,$fm and below.",
        "positive": "A Renormalization Group for Dynamical Triangulations in Arbitrary\n  Dimensions: A block spin renormalization group approach is proposed for the dynamical\ntriangulation formulation of quantum gravity in arbitrary dimensions.\nRenormalization group flow diagrams are presented for the three-dimensional and\nfour-dimensional theories near their respective transitions."
    },
    {
        "anchor": "Measuring interface tensions in 4d SU(N) lattice gauge theories: We propose a new algorithm to compute the order-order interface tension in\nSU(N) lattice gauge theories. The algorithm is trivially generalizable to a\nvariety of models, e.g., spin models. In the case N=3, via the perfect wetting\nhypothesis, we can estimate the order-disorder interface tension. In the case\nN=4, we study the ratio of dual k-tensions and find that it satisfies Casimir\nscaling down to T=1.2 T_c.",
        "positive": "Unified contraction algorithm for multi-baryon correlators on the\n  lattice: We propose a novel algorithm for calculating multi-baryon correlation\nfunctions on the lattice. By considering the permutation of quarks (Wick\ncontractions) and color/spinor contractions simultaneously, we construct a\nunified index list for the contraction where the redundancies in the original\ncontraction are eliminated. We find that a significant reduction in the\ncomputational cost of correlators is achieved, e.g., by a factor of 192 for\n$^3$H and $^3$He nuclei, and a factor of 20736 for the $^4$He nucleus, without\nassuming isospin symmetry. A further reduction is possible by exploiting\nisospin symmetry, and/or interchange symmetries associated with sink baryons,\nif such symmetries exist. Extensions for systems with hyperons are presented as\nwell."
    },
    {
        "anchor": "Nucleon electromagnetic form factors at high $Q^2$ from Wilson-clover\n  fermions: We present results on the nucleon electromagnetic form factors from Lattice\nQCD at momentum transfer up to about $12$~GeV$^2$. We analyze two gauge\nensembles with the Wilson-clover fermion action, a lattice spacing of $a\\approx\n0.09$~fm and pion masses $m_\\pi\\approx 170$~MeV and $m_\\pi\\approx 280$~MeV. In\nour analysis we employ momentum smearing as well as a set of techniques to\ninvestigate excited state effects. Good agreement with experiment and\nphenomenology is found for the ratios $G_E/G_M$ and $F_2/F_1$, whereas\ndiscrepancies are observed for the individual form factors $F_1$ and $F_2$. We\ndiscuss various systematics that may affect our calculation.",
        "positive": "Finite-size effects on a lattice calculation: We study in this paper the finite-size effects of a non-periodic lattice on a\nlattice calculation. To this end we use a finite lattice equipped with a\ncentral difference derivative with homogeneous boundary conditions to calculate\nthe bosonic mass associated to the Schwinger model. We found that the\nhomogeneous boundary conditions produce absence of fermion doubling and chiral\ninvariance, but we also found that in the continuum limit this lattice model\ndoes not yield the correct value of the boson mass as other models do. We\ndiscuss the reasons for this and, as a result, the matrix which cause the\nfermion doubling problem is identified."
    },
    {
        "anchor": "Ginsparg-Wilson Relation and Lattice Supersymmetry: The Ginsparg-Wilson(G-W) relation is extended for supersymmetric free\ntheories on a lattice.\n  Exact lattice supersymmetry(SUSY) can be defined without any ambiguities in\ndifference operators. The lattice action constructed by a block-spin\ntransformation is invariant under the symmetry. $U(1)_R$ symmetry on the\nlattice is also realized as one of exact symmetries.\n  For an application, the extended G-W relation is given for a two-dimensional\nmodel with chiral-multiplets. It is argued that the relation may be generalized\nfor interacting cases.",
        "positive": "Sign problem and phase quenching in finite-density QCD: models,\n  holography, and lattice: The effect of the complex phase of the fermion determinant is a key question\nrelated to the sign problem in finite-density QCD. Recently it has been shown\nthat ignoring the complex phase -- the phase quenching -- does not change\nphysics in a certain region of the phase diagram when a number of colors N_c is\nlarge. In this paper we study the effect of the phase quenching within the\nframeworks of effective models and holographic models. We show, in a unified\nmanner, that the phase quenching gives exact results for any fermionic\nobservables (e.g., chiral condensate) in the mean-field approximation and for\ngauge-invariant gluonic observables (e.g., Polyakov loop) to one-meson-loop\ncorrections beyond mean field. We also discuss implications for the lattice\nsimulations and confirm good quantitative agreement between our prediction and\nexisting lattice QCD results. Therefore the phase quenching provides rather\naccurate answer already at N_c=3 with small 1/N_c corrections which can be\ntaken into account by the phase reweighting."
    },
    {
        "anchor": "Diquarks in the nilpotency expansion of QCD and their role at finite\n  chemical potential: We assume that the most important quark correlations are pairwise at all\nbaryon densities. We introduce correlated pairs by means of Bogoliubov\ntransformations which are functions of time and spatial gauge fields, in the\nformalism of the transfer matrix with lattice regularization. The dependence on\ntime and gauge fields allows us to enforce gauge invariance and other\nsymmetries term by term in the transformed quantities. The resulting action\nshould be suitable for the description of multiquark mesons and baryons as\nstates of a quark and a diquark. We derive the quark contribution to the free\nenergy at finite chemical potential in a certain approximation. Its expression\ncannot be evaluated analytically, but it has a definite sign.",
        "positive": "Critical Flavor Number in the Three Dimensional Thirring Model: We present results of a Monte Carlo simulation of the three dimensional\nThirring model with the number of fermion flavors N_f varied between 2 and 18.\nBy identifying the lattice coupling at which the chiral condensate peaks,\nsimulations are be performed at couplings g^2(N_f) corresponding to the strong\ncoupling limit of the continuum theory. The chiral symmetry restoring phase\ntransition is studied as N_f is increased, and the critical number of flavors\nestimated as N_{fc}=6.6(1). The critical exponents measured at the transition\ndo not agree with self-consistent solutions of the Schwinger-Dyson equations;\nin particular there is no evidence for the transition being of infinite order.\nImplications for the critical flavor number in QED_3 are briefly discussed."
    },
    {
        "anchor": "Semileptonic Decays: an Update Down Under: Heavy-meson semileptonic decays calculations on the lattice are reviewed. The\nfocus is upon obtaining reliable matrix elements. Errors that depend upon the\nlattice spacing, $a$, are an important source of systematic error. Full $O(a)$\nimprovement of matrix elements for arbitrary-mass four-component quarks is\ndiscussed. With improvement, bottom-quark matrix elements can be calculated\ndirectly using current lattices. Momentum dependent errors for $O(a)$-improved\nquarks and statistical noise limit momenta to around 1 GeV/c with current\nlattices. Hence, maximum recoil momenta can be reached for $D$ decays while\nonly a fraction of the maximum recoil momentum can be reliably studied for the\nlight-meson decay modes of the $B$. Differential decay rates and partial widths\nare phenomenologically important quantities in $B$ decays that can be reliably\ndetermined with present lattices.",
        "positive": "Gauge--invariant field correlators in QCD at finite temperature: We study by numerical simulations on a lattice the behaviour of the\ngauge--invariant two--point correlation functions of the gauge field strengths\nacross the deconfinement phase transition."
    },
    {
        "anchor": "The $\u03b2$-function of $SU(3)$ gauge theory with $ N_f = 10 $ massless\n  fermions in the fundamental representation: We present the first study of the discrete $\\beta$-function of the $ SU(3) $\ngauge theory with 10 massless domain-wall fermions in the fundamental\nrepresentation. The renormalized coupling is obtained by the finite-volume\ngradient flow scheme, and the discrete $\\beta$-function is extrapolated to the\ncontinuum limit by the step-scaling method. Our result of the discrete\n$\\beta$-function (with $ s = 2 $) suggests that this theory possesses an\ninfrared fixed point around $ g_c^2 \\sim 7.0 $ for $ c = \\sqrt{8t}/L = 0.3 $.",
        "positive": "Clifford Fourier Transforms in (2+1)D Lattice Simulations of Soliton\n  Propagations: Monte Carlo simulation of solitonic phonon propagation on a 2D plane in Weyl\nfermion-sea is analyzed. We assume materials are filled with Weyl spinors\nlocated on $256\\times 256$ 2D lattice points, which are expressed by\nquaternions ${\\bf H}$. The topology of solitonic phonon propagation is defined\nby modifying fixed point actions of 4D Quantum Chromo Dynamics action to (2+1)D\naction, replacing Dirac fermions by Weyl fermions, and changing the electric\ncharge current flow to the energy flow. We consider $A$ type loops whose path\nare on a 2D plane, and $B$ type loops which contain two parallel links that\nconnect two 2D plane on different time slices. The length of loops are\nrestricted to be less than or equal to 8 lattice units. At the moment spatial\nlattice unit and time lattice unit are same. They can be chosen arbitrarily\nwhen one compares hysteresis effects with experimental data. Using the\nquaternion expression of Porteous, we calculate the plaquette part of loop\nactions and the link part of loop actions. Link actions of $A$ type loops\ncancel with each other, but those of $B$ type loops depends on whether the spin\nrotation is clockwise or that is counterclockwise. In the present work we\nconsider average of clockwise rotating and counterclockwise rotating loop\ncontributions."
    },
    {
        "anchor": "Static-static-light baryonic potentials: We determine doubly heavy baryonic potentials as a function of the distance\nbetween the two static sources, coupled to a light relativistic quark, for\ndifferent quantum numbers. We use the variational method to compute the ground\nstate and the first two excitations. These can be used as an input to\nnonrelativistic models or to NRQCD calculations of properties of doubly heavy\nbaryons. We compare our findings with a factorization model. We employ\nall-to-all propagator methods, improved by an additional hopping parameter\nexpansion and Wuppertal smearing on QCDSF configurations with two sea quark\nflavors.",
        "positive": "A Geometric Monte Carlo Algorithm for the Antiferromagnetic Ising model\n  with \"Topological\" Term at $\u03b8=\u03c0$: In this work we study the two and three-dimensional antiferromagnetic Ising\nmodel with an imaginary magnetic field $i\\theta$ at $\\theta=\\pi$. In order to\nperform numerical simulations of the system we introduce a new geometric\nalgorithm not affected by the sign problem. Our results for the $2D$ model are\nin agreement with the analytical solutions. We also present new results for the\n$3D$ model which are qualitatively in agreement with mean-field predictions."
    },
    {
        "anchor": "Phenomenology with Lattice NRQCD b Quarks: The HPQCD collaboration has used radiatively-improved NonRelativistic QCD\n(NRQCD) for $b$ quarks in bottomonium to determine the decay rate of $\\Upsilon$\nand $\\Upsilon^\\prime$ mesons to leptons in lattice QCD. Using time-moments of\nvector bottomonium current-current correlators, we are also able to determine\nthe $b$ quark mass in the $\\overline{\\mathrm{MS}}$ scheme. We use the same\nNRQCD $b$ quarks and Highly Improved Staggered Quark (HISQ) light quarks --\nwith masses down to their physical values -- to give a complete picture of\nheavy-light meson decay constants including those for vector mesons. We also\nstudy the semileptonic $B\\rightarrow\\pi\\ell\\nu$ decay at zero recoil to show\nthat lattice QCD is consistent with the soft pion theorem for this decay:\n$f_0(q^2_{\\mathrm{max}})=f_B/f_\\pi$ in the massless pion limit. Finally, we\npresent preliminary results for the $B_c \\rightarrow \\eta_c \\ell \\nu$\nsemileptonic decay form factors. This is a showcase for the comparison of\nresults for NRQCD $b$ quarks with those from HISQ $b$ quarks (both with HISQ\n$c$ quarks). We give the first 3-point results from our `heavy HISQ' programme,\nwhich will allow us to improve the normalisation of NRQCD-HISQ currents for\nother calculations.",
        "positive": "Quasi-static probes of the QCD plasma: Screening correlators and masses were studied at finite temperature in QCD\nwith two flavours of dynamical staggered quarks on a lattice. The spectrum of\nscreening masses show a hierarchical approach to chiral symmetry restoration.\nControl of explicit chiral symmetry breaking through the quark mass was shown\nto be an important step to understanding this phenomenon. No sign of decays was\nfound in the finite temperature scalar meson-like correlators in the confined\nphase."
    },
    {
        "anchor": "Finite Density Simulations with Canonical Ensemble: QCD at non-zero baryon density is expected to have a critical point where the\nzero-density cross-over turns into a first order phase transition. To identify\nthis point we scan the density-temperature space using a canonical ensemble\nmethod. For a given temperature, we plot the chemical potential as a function\nof density looking for an \"S-shape\" as a signal for a first order transition.\nWe carried out simulations using Wilson fermions with $m_\\pi \\approx 1{GeV}$ on\n$6^3\\times 4$ lattices. As a benchmark, we ran four flavors simulations where\nwe observe a clear signal. In the two flavors case we do not see any signal for\ntemperatures as low as $0.83 T_c$. Preliminary results for the three flavor\ncase are also presented.",
        "positive": "Quenched QCD at finite density: Simulations of quenched $QCD$ at relatively small but {\\it nonzero} chemical\npotential $\\mu$ on $32 \\times 16^3$ lattices indicate that the nucleon\nscreening mass decreases linearly as $\\mu$ increases predicting a critical\nchemical potential of one third the nucleon mass, $m_N/3$, by extrapolation.\nThe meson spectrum does not change as $\\mu$ increases over the same range, from\nzero to $m_\\pi/2$. Past studies of quenched lattice QCD have suggested that\nthere is phase transition at $\\mu = m_\\pi/2$. We provide alternative\nexplanations for these results, and find a number of technical reasons why\nstandard lattice simulation techniques suffer from greatly enhanced\nfluctuations and finite size effects for $\\mu$ ranging from $m_\\pi/2$ to\n$m_N/3$. We find evidence for such problems in our simulations, and suggest\nthat they can be surmounted by improved measurement techniques."
    },
    {
        "anchor": "Determination of ${\\bf f(\\infty)}$ from the Asymptotic Series for ${\\bf\n  f(x)}$ About ${\\bf x=0}$: A difficult and long-standing problem in mathematical physics concerns the\ndetermination of the value of $f(\\infty)$ from the asymptotic series for $f(x)$\nabout $x\\!=\\!0$. In the past the approach has been to convert the asymptotic\nseries to a sequence of Pad\\'e approximants $\\{P^n_n(x)\\}$ and then to evaluate\nthese approximants at $x\\!=\\!\\infty$. Unfortunately, for most physical\napplications the sequence $\\{P^n_n(\\infty)\\}$ is slowly converging and does not\nusually give very accurate results. In this paper we report the results of\nextensive numerical studies for a large class of functions $f(x)$ associated\nwith strong-coupling lattice approximations. We conjecture that for large $n$,\n$P^n_n(\\infty)\\!\\sim\\!f(\\infty)+B/\\ln n $. A numerical fit to this asymptotic\nbehavior gives an accurate extrapolation to the value of $f(\\infty )$.",
        "positive": "2-norm error bounds and estimates for Lanczos approximations to linear\n  systems and rational matrix functions: The Lanczos process constructs a sequence of orthonormal vectors v_m spanning\na nested sequence of Krylov subspaces generated by a hermitian matrix A and\nsome starting vector b. In this paper we show how to cheaply recover a\nsecondary Lanczos process starting at an arbitrary Lanczos vector v_m. This\nsecondary process is then used to efficiently obtain computable error estimates\nand error bounds for the Lanczos approximations to the action of a rational\nmatrix function on a vector. This includes, as a special case, the Lanczos\napproximation to the solution of a linear system Ax = b. Our approach uses the\nrelation between the Lanczos process and quadrature as developed by Golub and\nMeurant. It is different from methods known so far because of its use of the\nsecondary Lanczos process. With our approach, it is now in particular possible\nto efficiently obtain {\\em upper bounds} for the error in the {\\em 2-norm},\nprovided a lower bound on the smallest eigenvalue of $A$ is known. This holds\nin particular for a large class of rational matrix functions including best\nrational approximations to the inverse square root and the sign function. We\ncompare our approach to other existing error estimates and bounds known from\nthe literature and include results of several numerical experiments."
    },
    {
        "anchor": "Lattice Calculation of Heavy-Light Decay Constants with Two Flavors of\n  Dynamical Quarks: We present results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios in\nthe presence of two flavors of light sea quarks ($N_f=2$). We use Wilson light\nvalence quarks and Wilson and static heavy valence quarks; the sea quarks are\nsimulated with staggered fermions. Additional quenched simulations with\nnonperturbatively improved clover fermions allow us to improve our control of\nthe continuum extrapolation. For our central values the masses of the sea\nquarks are not extrapolated to the physical $u$, $d$ masses; that is, the\ncentral values are \"partially quenched.\" A calculation using \"fat-link clover\"\nvalence fermions is also discussed but is not included in our final results. We\nfind, for example, $f_B = 190 (7) (^{+24}_{-17}) (^{+11}_{-2}) (^{+8}_{-0})$\nMeV, $f_{B_s}/f_B = 1.16 (1) (2) (2) (^{+4}_{-0})$, $f_{D_s} = 241 (5)\n(^{+27}_{-26}) (^{+9}_{-4}) (^{+5}_{-0})$ MeV, and $f_{B}/f_{D_s} = 0.79 (2)\n(^{+5}_{-4}) (3) (^{+5}_{-0})$, where in each case the first error is\nstatistical and the remaining three are systematic: the error within the\npartially quenched $N_f=2$ approximation, the error due to the missing strange\nsea quark and to partial quenching, and an estimate of the effects of chiral\nlogarithms at small quark mass. The last error, though quite significant in\ndecay constant ratios, appears to be smaller than has been recently suggested\nby Kronfeld and Ryan, and Yamada. We emphasize, however, that as in other\nlattice computations to date, the lattice $u,d$ quark masses are not very light\nand chiral log effects may not be fully under control.",
        "positive": "Deconfinement in dense 2-color QCD: We study SU(2) lattice gauge theory with two flavors of Wilson fermion at\nnon-zero chemical potential mu and low temperature on a 8^3x16 system. We\nidentify three regimes along the mu-axis. For mu<~m_pi/2 the system remains in\nthe vacuum phase, and all physical observables considered remain essentially\nunchanged. The intermediate regime is characterised by a non-zero diquark\ncondensate and an associated increase in the baryon density, consistent with\nwhat is expected for Bose-Einstein condensation of tightly bound diquarks. We\nalso observe screening of the static quark potential here. In the high-density\ndeconfined regime we find a non-zero Polyakov loop and a strong modification of\nthe gluon propagator, including significant screening in the magnetic sector in\nthe static limit, which must have a non-perturbative origin. The behaviour of\nthermodynamic observables and the superfluid order parameter are consistent\nwith a Fermi surface disrupted by a BCS diquark condensate. The energy per\nbaryon as a function of mu exhibits a minimum in the deconfined regime,\nimplying that macroscopic objects such as stars formed in this theory are\nlargely composed of quark matter."
    },
    {
        "anchor": "Critical exponents and abelian dominance in $SU(2)$ QCD: The critical properties of the abelian Polyakov loop and the Polyakov loop in\nterms of Dirac string are studied in finite temperature abelian projected\n$SU(2)$ QCD. We evaluate the critical point and the critical exponents from\neach Polyakov loop in the maximally abelian gauge using the finite-size scaling\nanalysis. Abelian dominance in this case is proved quantitatively. The critical\npoint of each abelian Polyakov loop is equal to that of the non-abelian\nPolyakov loop within the statistical errors. Also, the critical exponents are\nin good agreement with those from non-abelian Polyakov loops.",
        "positive": "Tetraquarks, hadronic molecules, meson-meson scattering and disconnected\n  contributions in lattice QCD: There are generally two types of Wick contractions in lattice QCD\ncalculations of a correlation function --- connected and disconnected ones. The\ndisconnected contribution is difficult to calculate and noisy, thus it is often\nneglected. In the context of studying tetraquarks, hadronic molecules and\nmeson-meson scattering, we show that whenever there are both connected and\nsingly disconnected contractions, the singly disconnected part gives the\nleading order contribution, and thus should never be neglected. As an explicit\nexample, we show that information about the scalar mesons sigma, f0(980),\na0(980) and kappa will be lost when neglecting the disconnected contributions."
    },
    {
        "anchor": "Perturbative study of large $N$ principal chiral model with twisted\n  reduction: We compute the first four perturbative coefficients of the internal energy\nfor the twisted reduced principal chiral model (TRPCM) using numerical\nstochastic perturbation theory (NSPT). This matrix model has the same large $N$\nlimit as the ordinary principal chiral model (PCM) at infinite volume. Indeed,\nwe verify that the first three coefficients match the analytic result for the\nPCM coefficients at large $N$ with a precision of three to four significant\ndigits. The fourth coefficient also matches our own NSPT calculation of the\ncorresponding PCM coefficient at large $N$. The finite-$N$ corrections to all\ncoefficients beyond the leading order are smaller for TRPCM than for PCM. We\nanalyze the variance to determine the feasibility of extending the calculations\nto higher orders.",
        "positive": "Potential description of the charmonium from lattice QCD: We present spin-independent and spin-spin interquark potentials for\ncharmonium states, that are calculated using a relativistic heavy quark action\nfor charm quarks on the PACS-CS gauge configurations generated with the Iwasaki\ngauge action and 2+1 flavors of Wilson clover quark. The interquark potential\nwith finite quark masses is defined through the equal-time Bethe-Salpeter\namplitude. The light and strange quark masses are close to the physical point\nwhere the pion mass corresponds to $M_\\pi \\approx 156(7)$ MeV, and charm quark\nmass is tuned to reproduce the experimental values of $\\eta_c$ and $J/\\psi$\nstates. Our simulations are performed with a lattice cutoff of $a^{-1}\\approx\n2.2$ GeV and a spatial volume of $(3 {\\rm fm})^3$. We solve the nonrelativistic\nSchr\\\"odinger equation with resulting charmonium potentials as theoretical\ninputs. The resultant charmonium spectrum below the open charm threshold shows\na fairly good agreement with experimental data of well-established charmonium\nstates."
    },
    {
        "anchor": "Mass anomalous dimension of SU(2) using the spectral density method: SU(2) with N_f = 6 and N_f = 8 are believed to have an infrared conformal\nfixed point. We use the spectral density method cross referenced with the mass\nstep scaling method to evaluate the coupling constant dependence of the mass\nanomalous dimension for massless HEX smeared, clover improved Wilson fermions\nwith Schr\\\"odinger functional boundary conditions.",
        "positive": "Critical behaviour in the QCD Anderson transition: We study the Anderson-type localisation-delocalisation transition found\npreviously in the QCD Dirac spectrum at high temperature. Using high statistics\nQCD simulations with $N_f=2+1$ flavours of staggered quarks, we discuss how the\nchange in the spectral statistics depends on the volume, the temperature and\nthe lattice spacing, and we speculate on the possible universality of the\ntransition from Poisson to Wigner-Dyson in the spectral statistics. Moreover,\nwe show that the transition is a genuine phase transition: at the mobility\nedge, separating localised and delocalised modes, quantities characterising the\nspectral statistics become non-analytic in the thermodynamic limit. Using\nfinite size scaling we also determine the critical exponent of the correlation\nlength, and we speculate on possible extensions of the universality of Anderson\ntransitions."
    },
    {
        "anchor": "Scattering in a Euclidean formulation of relativistic quantum mechanics: A Euclidean formulation of relativistic quantum mechanics is discussed.\nRepresentations of the Hilbert space inner product and Poincar\\'e generators\nare all expressed in terms of Euclidean space-time variables. The formulation\ndoes not require analytic continuation and can be used to directly calculate\nscattering observables. A toy model is used to demonstrate the feasibility of\nperforming scattering calculations using the suggested computational methods.",
        "positive": "Vortex Structure in Abelian-Projected Lattice Gauge Theory: We report on a breakdown of both monopole dominance and positivity in\nabelian-projected lattice Yang-Mills theory. The breakdown is associated with\nobservables involving two units of the abelian charge. We find that the\nprojected lattice has at most a global $Z_2$ symmetry in the confined phase,\nrather than the global U(1) symmetry that might be expected in a dual\nsuperconductor or monopole Coulomb gas picture. Implications for monopole and\ncenter vortex theories of confinement are discussed."
    },
    {
        "anchor": "Triviality of $\\varphi^4$ theory in a finite volume scheme adapted to\n  the broken phase: We study the standard one-component $\\varphi^4$-theory in four dimensions. A\nrenormalized coupling is defined in a finite size renormalization scheme which\nbecomes the standard scheme of the broken phase for large volumes. Numerical\nsimulations are reported using the worm algorithm in the limit of infinite bare\ncoupling. The cutoff dependence of the renormalized coupling closely follows\nthe perturbative Callan Symanzik equation and the triviality scenario is hence\nfurther supported.",
        "positive": "A better conditioned Domain Wall Operator: A variation of the Domain Wall operator with an additional parameter alpha\nwill be introduced. The conditioning of the new Domain Wall operator depends on\nalpha, whereas the corresponding 4D propagator does not. The new and the\nconventional Domain Wall operator agree for alpha = 1. By tuning alpha, speed\nups of the linear system solvers of around 20% could be achieved."
    },
    {
        "anchor": "Regularizing QCD with staggered fermions and the fourth root trick: We investigate the properties of staggered-fermion lattice QCD in which the\nfourth root of the fermion determinant is taken. We show that this theory is\nnon-local at non-zero lattice spacing $a$, and that the non-locality is caused\nby the breaking of taste symmetry at $a\\ne 0$. We then present a\nrenormalization-group based argument that the theory restores taste symmetry in\nthe continuum limit. As a consequence the theory is local in that limit, and\nfalls into the correct universality class. Finally, we argue that the correct\neffective theory for the physics of Goldstone bosons at $a\\ne 0$ is given by\nstaggered chiral perturbation theory with the replica trick.",
        "positive": "Lattice QCD: Flavor Physics and Spectroscopy: We review highlights of recent results on the hadron spectrum and flavor\nphysics from lattice QCD. We also discuss recent rapid progress on the muon\nanomalous magnetic moment."
    },
    {
        "anchor": "Subsets and the canonical partition functions: We explain the physical nature of the subset solution to the sign problem in\nchiral random matrix theory: The subset sum is shown to project out the\ncanonical determinant with zero quark charge from a given configuration. As the\ngrand canonical chiral random matrix partition function is independent of the\nchemical potential, the zero quark charge sector provides the full result.",
        "positive": "Wilson Fermion Determinant in Lattice QCD: We present a formula for reducing the rank of Wilson fermions from $4 N_c N_x\nN_y N_z N_t$ to $4 N_c N_x N_y N_z$ keeping the value of its determinant. We\nanalyse eigenvalues of a reduced matrix and coefficients $C_n$ in the fugacity\nexpansion of the fermion determinant $\\sum_n C_n (\\exp(\\mu/T))^n$, which play\nan important role in the canonical formulation, using lattice QCD\nconfigurations on a $4^4$ lattice. Numerically, $\\log |C_n|$ varies as $N_x N_y\nN_z$, and goes easily over the standard numerical range; We give a simple cure\nfor that. The phase of $C_n$ correlates with the distribution of the Polyakov\nloop in the complex plain. These results lay the groundwork for future finite\ndensity calculations in lattice QCD."
    },
    {
        "anchor": "Non-perturbatively improved clover action for SU(2) gauge + fundamental\n  and adjoint representation fermions: The research of strongly coupled beyond-the-standard-model theories has\ngenerated significant interest in non-abelian gauge field theories with\ndifferent number of fermions in different representations. Motivated by the\nincreased interest to various technicolor scenarios, we study the\nnon-perturbative improvement of the Wilson-clover action with SU(2) gauge\nfields and 2 flavors of fermions in the fundamental and adjoint\nrepresentations. The Sheikholeslami-Wohlert coefficients are fixed using\nSchroedinger functional boundary conditions. The adjoint representation theory\nis a candidate for a \"minimal technicolor\" theory, already studied on the\nlattice using unimproved Wilson fermions.",
        "positive": "B meson decay constant from quenched Lattice QCD: A lattice QCD calculation of the B meson decay constant is presented. In\norder to investigate the scaling violation associated with the heavy quark,\nparallel simulations are carried out employing both Wilson and the\nO(a)-improved clover actions for the heavy quark. The discretization errors due\nto the large $b$ quark mass are estimated in a systematic way with the aid of\nthe non-relativistic interpretation approach of El-Khadra, Kronfeld and\nMackenzie. As our best value from the quenched simulations at $\\beta$=5.9, 6.1\nand 6.3 we obtain $f_B$=163$\\pm$16 MeV and $f_{B_s}$=175$\\pm$18 MeV in the\ncontinuum limit where the error includes both statistical and systematic\nuncertainties."
    },
    {
        "anchor": "Low energy effective theories on the lattice with coloured noise: Low energy effective theories give access to regimes of the QCD phase diagram\nthat to date are hard to simulate directly with lattice QCD or with functional\napproaches. For lattice QCD this includes the small temperature and/or large\ndensity regime. In both regimes the lower UV cutoff in low energy effective\ntheories may soften computational problems. Moreover, lattice results for low\nenergy effective theories serve as benchmark results for functional approaches\nfor these effective theories. Here we present lattice results for the scalar\nO($4$) and quark-meson models. We simulate the theory via Stochastic\nQuantisation and report on the effects of employing coloured noise, a method\nthat allows control over the momentum scale of the simulation.",
        "positive": "3-d lattice SU(3) free energy to four loops: We report on the perturbative computation of the 3d lattice Yang-Mills free\nenergy to four loops by means of Numerical Stochastic Perturbation Theory. The\nknown first and second orders have been correctly reproduced; the third and\nfourth order coefficients are new results and the known logarithmic IR\ndivergence in the fourth order has been correctly identified. Progress is being\nmade in switching to the gluon mass IR regularization and the related inclusion\nof the Faddeev-Popov determinant."
    },
    {
        "anchor": "Studies on the Chiral Order Parameter in the Schwinger Model: Based on an analytical technique using a unitary transformation and the\nvariational method, we study the chiral order parameter in the Schwinger model\nin the lattice formalism with Kogut-Susskind fermions. The fermion condensate\n$\\langle {\\bar\\Psi} \\Psi \\rangle $ for any coupling constant and fermion mass\nare calculated. Chiral symmetry is shown to be broken in the massless limit and\ngood scaling behavior is obtained.",
        "positive": "Towards Quantum Simulating Non-Abelian Gauge Theories: In this article, we review some of the recent developments towards the future\ngoal of quantum computing or quantum simulating lattice QCD. This includes a\nnovel theoretical framework developed for non-Abelian gauge theories that is\nthe first necessary step towards this goal. We also review some immediate\napplications of this framework in the context of both digital and analog\nquantum simulations of SU(2) lattice gauge theory coupled with staggered\nfermions."
    },
    {
        "anchor": "Finite-size scaling for four-dimensional Higgs-Yukawa model near the\n  Gaussian fixed point: We analyse finite-size scaling behaviour of a four-dimensional Higgs-Yukawa\nmodel near the Gaussian infrared fixed point. Through improving the mean-field\nscaling laws by solving one-loop renormalisation group equations, the\ntriviality property of this model can be manifested in the volume-dependence of\nmoments of the scalar-field zero mode. The scaling formulae for the moments are\nderived in this work with the inclusion of the leading-logarithmic corrections.\nTo test these formulae, we confront them with data from lattice simulations in\na simpler model, namely the O(4) pure scalar theory, and find numerical\nevidence of good agreement. Our results of the finite-size scaling can in\nprinciple be employed to establish triviality of Higgs-Yukawa models, or to\nsearch for alternative scenarios in studying their fixed-point structure, if\nsufficiently large lattices can be reached.",
        "positive": "Chiral symmetry breaking and quark confinement in the nilpotency\n  expansion of QCD: We apply to lattice QCD a bosonization method previously developed in which\ndynamical bosons are generated by time-dependent Bogoliubov transformations.\nThe transformed action can be studied by an expansion in the inverse of the\nnilpotency index, which is the number of fermionic states in the structure\nfunction of composite bosons. When this number diverges the model is solved by\nthe saddle point method which has a variational interpretation. We give a\nstationary covariant solution for a background matter field whose fluctuations\ndescribe mesons. In the saddle point approximations live fermionic\nquasiparticles with quark quantum numbers which are confined, in the sense that\nthey propagate only in pointlike color singlets. Conditions for chiral symmetry\nbreaking are determined, to be studied numerically, and a derivation of\nmesons-nucleons action is outlined."
    },
    {
        "anchor": "Testing algorithms for critical slowing down: We present the preliminary tests on two modifications of the Hybrid Monte\nCarlo (HMC) algorithm. Both algorithms are designed to travel much farther in\nthe Hamiltonian phase space for each trajectory and reduce the autocorrelations\namong physical observables thus tackling the critical slowing down towards the\ncontinuum limit. We present a comparison of costs of the new algorithms with\nthe standard HMC evolution for pure gauge fields, studying the autocorrelation\ntimes for various quantities including the topological charge.",
        "positive": "Convergence Rate and Locality of Improved Overlap Fermions: We construct new Ginsparg-Wilson fermions for QCD by inserting an\napproximately chiral Dirac operator - which involves ingredients of a perfect\naction - into the overlap formula. This accelerates the convergence of the\noverlap Dirac operator by a factor of 5 compared to the standard construction,\nwhich inserts the Wilson fermion as a point of departure. Taking into account\nthe effort for treating the improved fermion, we are left with an total\ncomputational overhead of about a factor 3. This remaining factor is likely to\nbe compensated by other virtues; here we show that the level of locality is\nclearly improved, so that the exponent of the correlation decay is doubled. We\nalso show that approximate rotation invariance is drastically improved, but a\ncareful scaling test has to be postponed."
    },
    {
        "anchor": "On systematic errors due to quenching in epsilon-prime over epsilon: Recently, we pointed out that chiral transformation properties of penguin\noperators change in the transition from unquenched to (partially) quenched QCD.\nAs a consequence, new operators appear in (partially) quenched QCD penguins,\nintroducing ambiguities which should be considered a quenching artifact. Here\nwe discuss more specifically the effects of this phenomenon on the quenched\nDelta I=1/2 K to pi pi amplitude, and in particular, its potential numerical\neffect on recent lattice estimates for epsilon-prime over epsilon.",
        "positive": "The Continuum and Leading Twist Limits of Parton Distribution Functions\n  in Lattice QCD: In this study, we present continuum limit results for the unpolarized parton\ndistribution function of the nucleon computed in lattice QCD. This study is the\nfirst continuum limit using the pseudo-PDF approach with Short Distance\nFactorization for factorizing lattice QCD calculable matrix elements. Our\nfindings are also compared with the pertinent phenomenological determinations.\nInter alia, we are employing the summation Generalized Eigenvalue Problem\n(sGEVP) technique in order to optimize our control over the excited state\ncontamination which can be one of the most serious systematic errors in this\ntype of calculations. A crucial novel ingredient of our analysis is the\nparameterization of systematic errors using Jacobi polynomials to characterize\nand remove both lattice spacing and higher twist contaminations, as well as the\nleading twist distribution. This method can be expanded in further studies to\nremove all other systematic errors."
    },
    {
        "anchor": "Nucleon form factors from quenched lattice QCD with domain wall fermions: We present a quenched lattice calculation of the weak nucleon form factors:\nvector (F_V(q^2)), induced tensor (F_T(q^2)), axial-vector (F_A(q^2)) and\ninduced pseudo-scalar (F_P(q^2)) form factors. Our simulations are performed on\nthree different lattice sizes L^3 x T=24^3 x 32, 16^3 x 32 and 12^3 x 32 with a\nlattice cutoff of 1/a = 1.3 GeV and light quark masses down to about 1/4 the\nstrange quark mass (m_{pi} = 390 MeV) using a combination of the DBW2 gauge\naction and domain wall fermions. The physical volume of our largest lattice is\nabout (3.6 fm)^3, where the finite volume effects on form factors become\nnegligible and the lower momentum transfers (q^2 = 0.1 GeV^2) are accessible.\nThe q^2-dependences of form factors in the low q^2 region are examined. It is\nfound that the vector, induced tensor, axial-vector form factors are well\ndescribed by the dipole form, while the induced pseudo-scalar form factor is\nconsistent with pion-pole dominance. We obtain the ratio of axial to vector\ncoupling g_A/g_V=F_A(0)/F_V(0)=1.219(38) and the pseudo-scalar coupling\ng_P=m_{mu}F_P(0.88m_{mu}^2)=8.15(54), where the errors are statistical erros\nonly. These values agree with experimental values from neutron beta decay and\nmuon capture on the proton. However, the root mean squared radii of the vector,\ninduced tensor and axial-vector underestimate the known experimental values by\nabout 20%. We also calculate the pseudo-scalar nucleon matrix element in order\nto verify the axial Ward-Takahashi identity in terms of the nucleon matrix\nelements, which may be called as the generalized Goldberger-Treiman relation.",
        "positive": "Staggered domain wall fermions: We construct domain wall fermions with a staggered kernel and investigate\ntheir spectral and chiral properties numerically in the Schwinger model. In\nsome relevant cases we see an improvement of chirality by more than an order of\nmagnitude as compared to usual domain wall fermions. Moreover, we present first\nresults for four-dimensional quantum chromodynamics, where we also observe\nsignificant reductions of chiral symmetry violations for staggered domain wall\nfermions."
    },
    {
        "anchor": "Lattice Fields and Extra Dimensions: Lattice gauge theory is now well into its third decade as a major subfield of\ntheoretical particle physics. I open these lattice sessions with a brief review\nof the motivations for this formulation of quantum field theory. I then comment\non the recent drive of lattice theorists to include a fictitious ``fifth''\ndimension to treat issues of chiral symmetry and anomalies.",
        "positive": "Simulating 2+1D Lattice Quantum Electrodynamics at Finite Density with\n  Neural Flow Wavefunctions: We present a neural flow wavefunction, Gauge-Fermion FlowNet, and use it to\nsimulate 2+1D lattice compact quantum electrodynamics with finite density\ndynamical fermions. The gauge field is represented by a neural network which\nparameterizes a discretized flow-based transformation of the amplitude while\nthe fermionic sign structure is represented by a neural net backflow. This\napproach directly represents the $U(1)$ degree of freedom without any\ntruncation, obeys Guass's law by construction, samples autoregressively\navoiding any equilibration time, and variationally simulates Gauge-Fermion\nsystems with sign problems accurately. In this model, we investigate\nconfinement and string breaking phenomena in different fermion density and\nhopping regimes. We study the phase transition from the charge crystal phase to\nthe vacuum phase at zero density, and observe the phase seperation and the net\ncharge penetration blocking effect under magnetic interaction at finite\ndensity. In addition, we investigate a magnetic phase transition due to the\ncompetition effect between the kinetic energy of fermions and the magnetic\nenergy of the gauge field. With our method, we further note potential\ndifferences on the order of the phase transitions between a continuous $U(1)$\nsystem and one with finite truncation. Our state-of-the-art neural network\napproach opens up new possibilities to study different gauge theories coupled\nto dynamical matter in higher dimensions."
    },
    {
        "anchor": "Lattice gauge ensembles and data management: The generation of ensembles of gauge configurations is a considerable\nexpense. The preservation and curation of these ensembles constitutes a\nvaluable shared resource for the lattice field theory community. The organizers\nof Lattice 2022 dedicated a parallel session to the presentation of gauge\nensembles and their generation, plans for ensemble publication and data\nmanagement/storage activities of different collaborations. A summary of the\ntwelve contributions is presented here.",
        "positive": "The 3-state Potts model as a heavy quark finite density laboratory: The 3-D Z(3) Potts model is a model for finite temperature QCD with heavy\nquarks. The chemical potential in QCD becomes an external magnetic field in the\nPotts model. Following Alford et al.\\cite{Alford_et_al}, we revisit this\nmapping, and determine the phase diagram for an arbitrary chemical potential,\nreal or imaginary. Analytic continuation of the phase transition line between\nreal and imaginary chemical potential can be tested with precision. Our results\nshow that the chemical potential weakens the heavy-quark deconfinement\ntransition in QCD."
    },
    {
        "anchor": "Adding Gauge Fields to Kaplan's Fermions: We experiment with adding dynamical gauge field to Kaplan (defect) fermions.\nIn the case of U(1) gauge theory we use an inhomogenous Higgs mechanism to\nrestrict the 3d gauge dynamics to a planar 2d defect. In our simulations the 3d\ntheory produce the correct 2d gauge dynamics. We measure fermion propagators\nwith dynamical gauge fields. They posses the correct chiral structure. The\nfermions at the boundary of the support of the gauge field (waveguide) are\nnon-chiral, and have a mass two times heavier than the chiral modes. Moreover,\nthese modes cannot be excited by a source at the defect; implying that they are\ndynamically decoupled. We have also checked that the anomaly relation is\nfullfilled for the case of a smooth external gauge field. This is an uuencoded\nps-file. Use 'uudecode hepchiral.ps.Z' and 'uncompress hepchiral.ps.Z' to\nproduce the psfile.",
        "positive": "Towards the Super Yang-Mills Theory on the Lattice: We present an entirely new approach towards a realization of the\nsupersymmetric Yang-Mills theory on the lattice. The action consists of the\nstaggered fermion and the plaquette variables distributed in the Euclidean\nspace with a particular pattern. The system is shown to have fermionic\nsymmetries relating the fermion and the link variables."
    },
    {
        "anchor": "A Demonstration of Hadron Mass Origin from QCD Trace Anomaly: Quantum chromodynamics (QCD) claims that the major source of the nucleon\ninvariant mass is not the Higgs mechanism but the trace anomaly in QCD energy\nmomentum tensor. Although experimental and theoretical results support such\nconclusion, a direct demonstration is still absent. We present the first\nLattice QCD calculation of the quark and gluon trace anomaly contributions to\nthe hadron masses, using the overlap fermion on the 2+1 flavor dynamical Domain\nwall quark ensemble at $m_{\\pi}=340$ MeV and lattice spacing $a=$0.1105 fm. The\nresult shows that the gluon trace anomaly contributes to most of the nucleon\nmass, and the contribution in the pion state is smaller than that in others\nnearly by a factor $\\sim$10 since the gluon trace anomaly density inside pion\nis different from the other hadrons and the magnitude is much smaller. The\ngluon trace anomaly coefficient $\\beta/g^3=-0.056(6)$ we obtained is consistent\nwith its regularization independent leading order value\n$(-11+\\frac{2N_f}{3})/(4\\pi)^2$ perfectly.",
        "positive": "Energy dependence of nucleon-nucleon potentials in lattice QCD: Recently a new approach to calculate the nuclear potential from lattice QCD\nhas been proposed. In the approach the nuclear potential is constructed from\nBethe-Salpeter (BS) wave functons through the Schroedinger equation. The\nprocedure leads to non-local but energy independent potential, which can be\nexpanded in terms of local functions. In several recent applications of this\nmethod, local potentials, which correspond to the leading order (LO) terms of\nthe expansion, are calculated from the BS wave function at E~0 MeV, where E is\nthe center of mass energy. It is therefore important to check the validity of\nthe LO approximation obtained at E~0. In this report, in order to check how\nwell the LO approximation for the NN potentials works, we compare the LO\npotentials determined from the BS wave function at E~45 MeV with those at E~0\nMeV in quenched QCD. We find that the difference of the LO potentials between\ntwo energies are not found wihin the statistical errors. This shows that the LO\napproximation for the potential is valid at low energies to describe the NN\ninteractions."
    },
    {
        "anchor": "A non-perturbative calculation of the mass of the Bc: We present a calculation of the mass of the 1S0 pseudoscalar anti-b c (Bc)\nstate using a non-perturbative measurement from quenched lattice QCD. We find\nM_Bc = 6.386(9)(98)(15) GeV where the first error is statistical, the second\nsystematic due to the quark mass ambiguities and quenching and the third the\nsystematic error due to the estimation of mass of the eta_b.",
        "positive": "Partial twisting for scalar mesons: The possibility of imposing partially twisted boundary conditions is\ninvestigated for the scalar sector of lattice QCD. According to the commonly\nshared belief, the presence of quark-antiquark annihilation diagrams in the\nintermediate state generally hinders the use of the partial twisting. Using\neffective field theory techniques in a finite volume, and studying the scalar\nsector of QCD with total isospin I=1, we however demonstrate that partial\ntwisting can still be performed, despite the fact that annihilation diagrams\nare present. The reason for this are delicate cancellations, which emerge due\nto the graded symmetry in partially quenched QCD with valence, sea and ghost\nquarks. The modified Luescher equation in case of partial twisting is given."
    },
    {
        "anchor": "Minimally doubled fermions and topology in 2D: We use the two-dimensional Schwinger model to investigate how lattice\nfermions perceive the global topological charge $q\\in\\mathbf{Z}$ of a given\ngauge background $U$. After a warm-up part devoted to staggered, Adams, Wilson\nand naive fermions, we consider Karsten-Wilczek and Borici-Creutz fermions,\nwhich are in the class of minimally doubled lattice fermion actions. We focus\non the eigenvalue spectrum and the chiralities of the pertinent eigenmodes.\nWithout modification both minimally doubled actions are found to be insensitive\nto topology, but in either case it is possible to define a suitable\nspecies-splitting term to make the resulting operator topology aware.",
        "positive": "The Landau gauge lattice QCD simulation and the gluon propagator: The gluon propagator in the Landau gauge lattice QCD simulation of quenched\n8^3 x 16 lattice is measured. The data suggests the confinement mechanism of\nthe Gribov-Zwanziger theory."
    },
    {
        "anchor": "Calculation of the strange quark mass using domain wall fermions: We present a first calculation of the strange quark mass using domain wall\nfermions. This paper contains an overview of the domain wall discretization and\na pedagogical presentation of the perturbative calculation necessary for\ncomputing the mass renormalization. We combine the latter with numerical\nsimulations to estimate the strange quark mass. Our final result in the\nquenched approximation is 95(26) MeV in the ${\\bar{MS}}$ scheme at a scale of 2\nGeV. We find that domain wall fermions have a small perturbative mass\nrenormalization, similar to Wilson quarks, and exhibit good scaling behavior.",
        "positive": "Adjoint string breaking in 4d SU(2) Yang-Mills theory: We compute the static potential of adjoint sources in SU(2) Yang-Mills theory\nin four dimensions by numerical Monte Carlo simulations. Following a recent\ncalculation in 2+1 dimensions, we employ a variational approach involving\nstring and gluelump operators and obtain clear evidence for string breaking and\nthe saturation of the potential at large distances. For the string breaking\nscale we find $r_b \\approx 1.25{\\rm fm}, 2.3 r_0$, or in units of the lightest\nglueball, $r_b m_{0++} \\approx 9.7$. We furthermore resolve the first\nexcitation of the flux-tube and observe its breaking as well. The result for\n$r_b$ is in remarkable quantitative agreement with the three-dimensional one."
    },
    {
        "anchor": "Non perturbative physics from NSPT: renormalons, the gluon condensate\n  and all that: Numerical Stochastic Perturbation Theory (NSPT) enables very high order\ncomputations in Lattice Gauge Theories. We report on the determination of the\ngluon condensate from lattice QCD measurements of the basic plaquette. This is\na long standing problem, which was eventually solved a few years ago in pure\ngauge. In this context NSPT is crucial: it is actually the only tool enabling\nthe subtraction of the power divergent contribution associated to the identity\noperator in the OPE for the plaquette. This subtraction is actually a delicate\nissue, since the perturbative expansion of the plaquette is on general ground\nexpected to be an asymptotic one, due to renormalons. This in turn results in\nambiguities and the separation of scales in the OPE does not correspond to a\nseparation of perturbative and non-perturbative contributions. All in all, one\nneeds to absorb the ambiguities attached to the perturbative series into the\ndefinition of the condensate itself, i.e. one needs a prescription. A possible\none amounts to summing the perturbative series up to its minimal term, which\nmeans computing up to orders which only NSPT can aim at. Our computation is the\nfirst one in QCD, with massless staggered fermions. In order to remove the\nzero-mode of the gauge field, twisted boundary conditions are adopted for the\nlatter, consistently coupled to fermions in the fundamental representation\nsupplemented with smell degrees of freedom.",
        "positive": "mc4qcd: Online Analysis Tool for Lattice QCD: mc4qcd is a web based collaboration tool for analysis of Lattice QCD data.\nLattice QCD computations consists of a large scale Markov Chain Monte Carlo.\nMultiple measurements are performed at each MC step. Our system acquires the\ndata by uploading log files, parses them for results of measurements, filters\nthe data, mines for required information by aggregating results, represents the\nresults as plots and histograms, and it further allows refining and interaction\nby fitting the results. The system computes moving averages and\nautocorrelations, builds bootstrap samples and bootstrap errors, and allows\nmodeling the data using Bayesian correlated constrained linear and non-linear\nfits. It can be scripted to allow real time visualization of results form an\nongoing computation. The system is modular and it can be adapted to automating\nthe analysis workflow of different types of MC computations."
    },
    {
        "anchor": "A Lattice Simulation of the SU(2) Vacuum Structure: In this article we analyze the vacuum structure of pure SU(2) Yang-Mills\nusing non-perturbative techniques. Monte Carlo simulations are performed for\nthe lattice gauge theory with external sources to obtain the effective\npotential. Evidence from the lattice gauge theory indicating the presence of\nthe unstable mode in the effective potential is reported.",
        "positive": "Anderson localization through Polyakov loops: lattice evidence and\n  Random matrix model: We investigate low-lying fermion modes in SU(2) gauge theory at temperatures\nabove the phase transition. Both staggered and overlap spectra reveal\ntransitions from chaotic (random matrix) to integrable (Poissonian) behavior\naccompanied by an increasing localization of the eigenmodes. We show that the\nlatter are trapped by local Polyakov loop fluctuations. Islands of such \"wrong\"\nPolyakov loops can therefore be viewed as defects leading to Anderson\nlocalization in gauge theories. We find strong similarities in the spatial\nprofile of these localized staggered and overlap eigenmodes. We discuss\npossible interpretations of this finding and present a sparse random matrix\nmodel that reproduces these features."
    },
    {
        "anchor": "Ising string beyond Nambu-Goto: A major result of the Effective String Theory (EST) description of\nconfinement is the so called \"low energy universality,\" which states that the\nfirst few terms of the large distance expansion of any EST are universal and\ncoincide with those of the Nambu-Goto action. Going beyond this approximation\nis one of the most interesting open problems in the EST. In the higher order\nterms beyond Nambu-Goto several important pieces of physical information are\nencoded, which could improve our understanding of the physical mechanisms\nbehind confinement and of the physical degrees of freedoms which originate the\nEST. In this paper we evaluate numerically the first two of these corrections\nin the case of the three dimensional gauge Ising model. The first of them turns\nout to be negative: $\\gamma_3=-0.00048(4)$, similar (but not equal) to the one\nrecently measured in the $SU(2)$ Yang Mills theory in three dimensions and\ncompatible with the bootstrap bound $\\gamma_3 \\geq -\\frac{1}{768}$.",
        "positive": "Phase Diagram of QCD at Finite Temperatures with Wilson Fermions: Phase diagram of QCD with Wilson fermions for various numbers of flavors\n$N_F$ is discussed. Our simulations mainly performed on a lattice with the\ntemporal size $N_t =4$ indicate the following: The chiral phase transition is\nof first order when $3 \\le N_F \\le 6$, while it is continuous when $N_F=2$. For\nthe realistic case of massless u and d quarks and the strange quark with $m_q =\n150$ MeV, the phase transition is first order. The sharp transition in the\nintermediate mass region for $N_F=2$ at $N_t=4$ observed by the MILC group\ndisappears when an RG improvement is made for the pure gauge action."
    },
    {
        "anchor": "Masses and decay constants of the $\u03b7$ and $\u03b7^\\prime$ mesons from\n  lattice QCD: We determine the masses, the singlet and octet decay constants as well as the\nanomalous matrix elements of the $\\eta$ and $\\eta^\\prime$ mesons in $N_f=2+1$\nQCD\\@. The results are obtained using twenty-one CLS ensembles of\nnon-perturbatively improved Wilson fermions that span four lattice spacings\nranging from $a\\approx 0.086\\,$fm down to $a\\approx 0.050\\,$fm. The pion masses\nvary from $M_{\\pi}=420\\,$MeV to $126\\,$MeV and the spatial lattice extents\n$L_s$ are such that $L_sM_\\pi\\gtrsim 4$, avoiding significant finite volume\neffects. The quark mass dependence of the data is tightly constrained by\nemploying two trajectories in the quark mass plane, enabling a thorough\ninvestigation of U($3$) large-$N_c$ chiral perturbation theory (ChPT). The\ncontinuum limit extrapolated data turn out to be reasonably well described by\nthe next-to-leading order ChPT parametrization and the respective low energy\nconstants are determined. The data are shown to be consistent with the singlet\naxial Ward identity and, for the first time, also the matrix elements with the\ntopological charge density are computed. We also derive the corresponding\nnext-to-leading order large-$N_{c}$ ChPT formulae. We find $F^8 =\n115.0(2.8)~\\text{MeV}$, $\\theta_{8} = -25.8(2.3)^{\\circ}$, $\\theta_0 =\n-8.1(1.8)^{\\circ}$ and, in the $\\overline{\\mathrm{MS}}$ scheme for $N_f=3$,\n$F^{0}(\\mu = 2\\,\\mathrm{GeV}) = 100.1(3.0)~\\text{MeV}$, where the decay\nconstants read $F^8_\\eta=F^8\\cos \\theta_8$, $F^8_{\\eta^\\prime}=F^8\\sin\n\\theta_8$, $F^0_\\eta=-F^0\\sin \\theta_0$ and $F^0_{\\eta^\\prime}=F^0\\cos\n\\theta_0$. For the gluonic matrix elements, we obtain $a_{\\eta}(\\mu =\n2\\,\\mathrm{GeV}) = 0.0170(10)\\,\\mathrm{GeV}^{3}$ and $a_{\\eta^{\\prime}}(\\mu =\n2\\,\\mathrm{GeV}) = 0.0381(84)\\,\\mathrm{GeV}^{3}$, where statistical and all\nsystematic errors are added in quadrature.",
        "positive": "Lattice gauge theory computation of the static force: We explore a novel approach to compute the force between a static quark and a\nstatic antiquark with lattice gauge theory directly. The approach is based on\nexpectation values of Wilson loops or Polyakov loops with chromoelectric field\ninsertions. We discuss theoretical and technical aspects in detail, in\nparticular, how to compensate large discretization errors with a multiplicative\nrenormalization factor and the evaluation using a multilevel algorithm. We also\ncompare numerical results for the static force to corresponding results\nobtained in the traditional way, i.e., by computing first the static potential\nand then taking the derivative."
    },
    {
        "anchor": "The $\u0394(1232)$ axial charge and form factors from lattice QCD: We present the first calculation on the $\\Delta$ axial-vector and\npseudoscalar form factors using lattice QCD. Two Goldberger-Treiman relations\nare derived and examined. A combined chiral fit is performed to the nucleon\naxial charge, N to $\\Delta$ axial transition coupling constant and $\\Delta$\naxial charge.",
        "positive": "Hadronic decays from the lattice: I review the lattice QCD approach to determining hadronic decay transitions.\nExamples considered include rho to pi pi; b_1 to pi omega; hybrid meson decays\nand scalar meson decays. I discuss what lattices can provide to help understand\nthe composition of hadrons."
    },
    {
        "anchor": "An analysis of systematic effects in finite size scaling studies using\n  the gradient flow: We propose a new strategy for the determination of the step scaling function\n$\\sigma(u)$ in finite size scaling studies using the Gradient Flow. In this\napproach the determination of $\\sigma(u)$ is broken in two pieces: a change of\nthe flow time at fixed physical size, and a change of the size of the system at\nfixed flow time. Using both perturbative arguments and a set of simulations in\nthe pure gauge theory we show that this approach leads to a better control over\nthe continuum extrapolations. Following this new proposal we determine the\nrunning coupling at high energies in the pure gauge theory and re-examine the\ndetermination of the $\\Lambda$-parameter, with special care on the perturbative\ntruncation uncertainties.",
        "positive": "The Chiral Extrapolation of Strange Matrix Elements in the Nucleon: In current lattice simulations of nucleon properties, the up and down quark\nmasses are significantly larger than their physical values, while the strange\nquark can be included in simulations with its physical mass. When the up and\ndown quark masses are much smaller than the strange-quark mass the chiral\nextrapolation of strange-quark matrix elements in the nucleon from the lattice\nup and down quark masses to their physical values can be performed with\ntwo-flavor chiral perturbation theory, thereby avoiding the slow convergence\nproblem of the three-flavor chiral expansion. We explore the chiral expansion\nof several matrix elements of strange operators in the nucleon in two-flavor\nchiral perturbation theory and two-flavor partial-quenched chiral perturbation\ntheory."
    },
    {
        "anchor": "Strings in SU(N) gauge theories in 2+1 dimensions: beyond the\n  fundamental representation: We calculate energies and tensions of closed k-strings in (2+1)-dimensional\nSU(N) gauge theories with N=4,5,6,8. When we study the dependence of the ground\nstate energy on the string length, we find that it is well described by a\nNambu-Goto (NG) free bosonic string for large lengths. At shorter lengths we\nsee deviations which we fit, and this allows us to control the systematic error\ninvolved in extracting the tension. We compare the resulting string tensions\nwith Casimir scaling, which we find to be lower than our data by 1%-4%.\nExtrapolating our results to N=oo we see that our data fits more naturally to\n1/N rather than 1/N^2 corrections. Finally, we see that the full spectrum of\nthe k-string states falls into sectors that belong to particular irreducible\nrepresentations of SU(N).",
        "positive": "Towards a non-perturbative measurement of the heavy quark momentum\n  diffusion coefficient: We report on a lattice investigation of heavy quark diffusion within pure\nSU(3) plasma above the deconfinement transition, with the quarks treated to\nleading order in the heavy mass expansion. Using a multilevel algorithm,\nseveral volumes and lattice spacings, as well as tree-level improvement and\nperturbative renormalization, we measure the relevant \"colour-electric\"\nEuclidean correlator, finding that it clearly exceeds its perturbative\ncounterpart. Even without analytic continuation, this suggests that at\ntemperatures just above the critical one, non-perturbative interactions felt by\nthe heavy quarks are stronger than within the weak-coupling expansion. After\nintroducing rough modelling of the spectral shape, diffusion coefficients down\nto D ~ 0.5/T appear possible."
    },
    {
        "anchor": "Nucleon axial charge from quenched lattice QCD with domain wall fermions\n  and DBW2 gauge action: The domain wall fermion (DWF) method, with its almost perfectly preserved\nchiral symmetry on the lattice, makes the calculation of the nucleon axial\ncharge particularly easy. By maintaining chiral symmetry and using the\nWard-Takahashi (WT) identity, one has Z_A = Z_V and the bare lattice\ncalculation yields the physical value without explicit renormalization. The\nDBW2 improved gauge action provides further enhancement of the symmetry and\nhence a more accurate WT identity at coarse lattice spacing. Taking advantage\nof these methods, we confirmed a significant volume dependence of the nucleon\naxial charge on (1.2 fm)^3 and (2.4 fm)^3 lattice volumes.",
        "positive": "Monopoles in the Plaquette Formulation of the 3D SU(2) Lattice Gauge\n  Theory: Using a plaquette formulation for lattice gauge models we describe monopoles\nof the three dimensional SU(2) theory which appear as configurations in the\ncomplete axial gauge and violate the continuum Bianchi identity. Furthemore we\nderive a dual formulation for the Wilson loop in arbitrary representation and\ncalculate the form of the interaction between generated electric flux and\nmonopoles in the region of a weak coupling relevant for the continuum limit.\nThe effective theory which controls the interaction is of the sine-Gordon type\nmodel. The string tension is calculated within the semiclassical approximation."
    },
    {
        "anchor": "Topological Susceptibility of the 2d O(3) Model under Gradient Flow: The 2d O(3) model is widely used as a toy model for ferromagnetism and for\nQuantum Chromodynamics. With the latter it shares --- among other basic aspects\n--- the property that the continuum functional integral splits into topological\nsectors. Topology can also be defined in its lattice regularised version, but\nsemi-classical arguments suggest that the topological susceptibility $\\chi_{\\rm\nt}$ does not scale towards a finite continuum limit. Previous numerical studies\nconfirmed that the quantity $\\chi_{\\rm t}\\, \\xi^{2}$ diverges at large\ncorrelation length $\\xi$. Here we investigate the question whether or not this\ndivergence persists when the configurations are smoothened by the Gradient Flow\n(GF). The GF destroys part of the topological windings; on fine lattices this\nstrongly reduces $\\chi_{\\rm t}$. However, even when the flow time is so long\nthat the GF impact range --- or smoothing radius --- attains $\\xi/2$, we do\nstill not observe evidence of continuum scaling.",
        "positive": "Two-flavour Schwinger model with dynamical fermions in the L\u00fcscher\n  formalism: We report preliminary results for 2D massive QED with two flavours of Wilson\nfermions, using the Hermitean variant of L\\\"uscher's bosonization technique.\nThe chiral condensate and meson masses are obtained. The simplicity of the\nmodel allows for high statistics simulations close to the chiral and continuum\nlimit, both in the quenched approximation and with dynamical fermions."
    },
    {
        "anchor": "Fat and Thin Fisher Zeroes: We show that it is possible to determine the locus of Fisher zeroes in the\nthermodynamic limit for the Ising model on planar (``fat'') phi4 random graphs\nand their dual quadrangulations by matching up the real part of the high- and\nlow-temperature branches of the expression for the free energy. Similar methods\nwork for the mean-field model on generic, ``thin'' graphs. Series expansions\nare very easy to obtain for such random graph Ising models.",
        "positive": "The curvature of the QCD phase transition line: We determine the curvature of the phase transition line in the mu-T plane\nthrough an analysis of various observables, including the Polyakov loop, the\nquark number susceptibilities and the susceptibility of the chiral condensate.\nThe second derivative of these quantities with respect to mu was calculated.\nThe measurements were carried out on N_T = 4,6,8 and 10 lattices generated with\na Symanzik improved gauge and stout-link improved 2+1 flavour staggered fermion\naction using physical quark masses."
    },
    {
        "anchor": "Dual Non-Abelian Yang-Mills Simulations in Four Dimensions: We present numerical results for pure SU(2) Yang-Mills theory in four\nspace-time dimensions using a novel algorithm based on dually transformed\nvariables. The simulation makes use of a recently derived O(j^4) algorithm for\nthe dual vertex amplitude and a dual Metropolis algorithm that generalizes the\none recently developed for three dimensions. The dual algorithm is validated\nagainst the equivalent model using conventional variables over a range of\ncouplings, spin cut-offs, and lattice sizes. We consider a lattice size up to\n8x8x8x8, where the problem of negative amplitudes renders the simulation\nresults excessively noisy even at a relatively low beta (starting at about\nbeta=1.8). In conclusion, we survey some approaches to addressing the sign\nproblem in this context and increasing the efficiency of dual computations\nwithin this approach.",
        "positive": "Chiral Symmetry Breaking in QED induced by an External Magnetic Field: We simulate Lattice QED in a constant external magnetic field using the RHMC\nalgorithm. We seek evidence for chiral symmetry breaking predicted by truncated\nSchwinger-Dyson methods. Since the predicted values of the dynamical electron\nmass and chiral condensate at the physical fine structure constant are too\nsmall to be measured, we simulate at a larger value $\\alpha=1/5$. This requires\nusing electron masses as low as $m=0.001$ to extrapolate to $m=0$. At a large\nmagnetic field, the electrons occupy the lowest Landau level which has a small\nprofile in the plane orthogonal to the magnetic field, so that we are able to\nuse a lattice with small extent in these 2 directions. If chiral symmetry is\nunbroken at $m=0$ the chiral condensate is dominated by large momenta and\nshould be insensitive to the lattice extent in the direction of the magnetic\nfield and the time direction. When chiral symmetry is broken at $m=0$, the\nchiral condensate should be sensitive to the lattice size in these directions\nas $m \\rightarrow 0$. We search for this behaviour by increasing the lattice\nextent in these 2 directions. Preliminary simulations show strong dependence of\nthe chiral condensate on the lattice extent in these 2 directions for the\nsmallest masses, and these increased condensates appear to be approaching a\nnon-zero limit as $m \\rightarrow 0$."
    },
    {
        "anchor": "Improving the theoretical prediction for the $B_s-\\bar{B}_s$ width\n  difference: matrix elements of next-to-leading order $\u0394B=2$ operators: We present lattice QCD results for the matrix elements of $R_2$ and other\ndimension-7, $\\Delta B = 2$ operators relevant for calculations of $\\Delta\n\\Gamma_s$, the $B_s-\\bar{B}_s$ width difference. We have computed correlation\nfunctions using 5 ensembles of the MILC Collaboration's 2+1+1-flavour gauge\nfield configurations, spanning 3 lattice spacings and light sea quarks masses\ndown to the physical point. The HISQ action is used for the valence strange\nquarks, and the NRQCD action is used for the bottom quarks. Once our analysis\nis complete, the theoretical uncertainty in the Standard Model prediction for\n$\\Delta \\Gamma_s$ will be substantially reduced.",
        "positive": "Long distance contribution to the $K_L-K_S$ mass difference: We develop and demonstrate techniques needed to compute the long distance\ncontribution to the $K_{L}$-$K_{S}$ mass difference, $\\Delta M_K$, in lattice\nQCD and carry out a first, exploratory calculation of this fundamental\nquantity. The calculation is performed on 2+1 flavor, domain wall fermion,\n$16^3\\times32$ configurations with a 421 MeV pion mass and an inverse lattice\nspacing $1/a=1.73$ GeV. We include only current-current operators and drop all\ndisconnected and double penguin diagrams. The short distance part of the mass\ndifference in a 2+1 flavor calculation contains a quadratic divergence cut off\nby the lattice spacing. Here, this quadratic divergence is eliminated through\nthe GIM mechanism by introducing a valence charm quark. The inclusion of the\ncharm quark makes the complete calculation accessible to lattice methods\nprovided the discretization errors associated with the charm quark can be\ncontrolled. The long distance effects are discussed for each parity channel\nseparately. While we can see a clear signal in the parity odd channel, the\nsignal to noise ratio in the parity even channel is exponentially decreasing as\nthe separation between the two weak operators increases. We obtain a mass\ndifference $\\Delta M_K$ which ranges from $6.58(30)\\times 10^{-12}$ MeV to\n$11.89(81)\\times 10^{-12}$ MeV for kaon masses varying from 563 MeV to 839 MeV.\nExtensions of these methods are proposed which promise accurate results for\nboth $\\Delta M_K$ and $\\epsilon_K$, including long distance effects."
    },
    {
        "anchor": "Taste non-Goldstone, flavor-charged pseudo-Goldstone boson decay\n  constants in staggered chiral perturbation theory: We calculate the axial current decay constants of taste non-Goldstone pions\nand kaons in staggered chiral perturbation theory through next-to-leading\norder. The results are a simple generalization of the results for the taste\nGoldstone case. New low-energy couplings are limited to analytic corrections\nthat vanish in the continuum limit; certain coefficients of the chiral\nlogarithms are modified, but they contain no new couplings. We report results\nfor quenched, fully dynamical, and partially quenched cases of interest in the\nchiral SU(3) and SU(2) theories.",
        "positive": "Symanzik improvement of the gradient flow in lattice gauge theories: We apply the Symanzik improvement programme to the 4+1-dimensional local\nre-formulation of the gradient flow in pure $SU(N)$ lattice gauge theories. We\nshow that the classical nature of the flow equation allows to eliminate all\ncutoff effects at $\\mathcal O(a^2)$ which originate either from the discretized\ngradient flow equation or from the gradient flow observable. All the remaining\n$\\mathcal O(a^2)$ effects can be understood in terms of local counterterms at\nthe zero flow time boundary. We classify these counterterms and provide a\ncomplete set as required for on-shell improvement. Compared to the\n4-dimensional pure gauge theory only a single additional counterterm is\nrequired, which corresponds to a modified initial condition for the flow\nequation. A consistency test in perturbation theory is passed and allows to\ndetermine all counterterm coefficients to lowest non-trivial order in the\ncoupling."
    },
    {
        "anchor": "I=2 Pion Scattering Length from Two-Pion Wave Functions: We calculate the two-pion wave function in the ground state of the I=2\n$S$-wave system and find the interaction range between two pions, which allows\nus to examine the validity of the necessary condition for the finite-volume\nmethod for the scattering length proposed by L\\\"uscher. We work in the quenched\napproximation employing a renormalization group improved gauge action for\ngluons and an improved Wilson action for quarks at $1/a=1.207(12) {\\rm GeV}$ on\n$16^3 \\times 80$, $20^3 \\times 80$ and $24^3 \\times 80$ lattices. We conclude\nthat the necessary condition is satisfied within the statistical errors for the\nlattice sizes $L\\ge 24$ ($3.92 {\\rm fm}$) when the quark mass is in the range\nthat corresponds to $m_\\pi^2 = 0.273-0.736 {\\rm GeV}^2$. We obtain the\nscattering length with a smaller statistical error from the wave function than\nfrom the two-pion time correlator.",
        "positive": "The Continuum Phase Diagram of the 2d Non-Commutative lambda phi**4\n  Model: We present a non-perturbative study of the lambda phi**4 model on a\nnon-commutative plane. The lattice regularised form can be mapped onto a\nHermitian matrix model, which enables Monte Carlo simulations. Numerical data\nreveal the phase diagram; at large lambda it contains a \"striped phase\", which\nis absent in the commutative case. We explore the question whether or not this\nphenomenon persists in a Double Scaling Limit (DSL), which extrapolates\nsimultaneously to the continuum and to infinite volume, at a fixed\nnon-commutativity parameter. To this end, we introduce a dimensional lattice\nspacing based on the decay of the correlation function. Our results provide\nevidence for the existence of a striped phase even in the DSL, which implies\nthe spontaneous breaking of translation symmetry. Due to the non-locality of\nthis model, this does not contradict the Mermin-Wagner Theorem."
    },
    {
        "anchor": "$\u039b_c N$ interaction from lattice QCD and its application to\n  $\u039b_c$ hypernuclei: The interaction between $\\Lambda_c$ and a nucleon ($N$) is investigated by\nemploying the HAL QCD method in the (2+1)-flavor lattice QCD on a\n$(2.9~\\mathrm{fm})^3$ volume at $m_\\pi \\simeq 410,~570,~700$ MeV. We study the\ncentral potential in $^1S_0$ channel as well as central and tensor potentials\nin $^3S_1 - $$^3D_1$ channel, and find that the tensor potential for $\\Lambda_c\nN$ is negligibly weak and central potentials in both $^1S_0$ and $^3S_1 -\n$$^3D_1$ channels are almost identical with each other except at short\ndistances. Phase shifts and scattering lengths calculated with these potentials\nshow that the interaction of $\\Lambda_c N$ system is attractive and has a\nsimilar strength in $^1S_0$ and $^3S_1$ channels at low energies (i.e. the\nkinetic energy less than about $40$ MeV). While the attractions are not strong\nenough to form two-body bound states, our results lead to a possibility to form\n$\\Lambda_c$ hypernuclei for sufficiently large atomic numbers ($A$). To\ndemonstrate this, we derive a single-folding potential for $\\Lambda_c$\nhypernuclei from the $\\Lambda_c$-nucleon potential obtained in lattice QCD, and\nfind that $\\Lambda_c$ hypernuclei can exist for $A \\ge 12$ with the binding\nenergies of a few MeV. We also estimate the Coulomb effect for the $\\Lambda_c$\nhypernuclei.",
        "positive": "Impact of Z_2 monopoles and vortices on the deconfinement transition: The impact of Z_2-monopoles and vortices on the bulk and the deconfinement\nphase transitions of the SU(2) lattice gauge theory with a mixed Villain form\nof action is investigated by varying their numbers with appropriate chemical\npotentials. Suppressing the former shifts the line of deconfinement transitions\nin the coupling plane but it continues to behave also like the bulk transition\nline. We find separate deconfinement and bulk phase transitions on the same\nlattice, suggesting the two to be indeed coincident at higher adjoint\ncouplings. Universality is restored when both monopoles and vortices are\nsuppressed."
    },
    {
        "anchor": "Full QCD on APE100 Machines: We present the first tests and results from a study of QCD with two flavours\nof dynamical Wilson fermions using the Hybrid Monte Carlo Algorithm (HMCA) on\nAPE100 machines.",
        "positive": "Four-loop contributions to long-distance quantities in the\n  two-dimensional nonlinear sigma-model on a square lattice: revised numerical\n  estimates: We give the correct analytic expression of a finite integral appearing in the\nfour-loop computation of the renormalization-group functions for the\ntwo-dimensional nonlinear sigma-model on the square lattice with standard\naction, explaining the origin of a numerical discrepancy. We revise the\nnumerical expressions of Caracciolo and Pelissetto for the perturbative\ncorrections of the susceptibility and of the correlation length. For the values\nused in Monte Carlo simulations, N=3, 4, 8, the second perturbative correction\ncoefficient of the correlation length varies by 3%, 4%, 3% respectively. Other\nquantities vary similarly."
    },
    {
        "anchor": "On P-vortices and the Gribov problem: We study the possible connection between centre vortices and P-vortices in\nSU(2) gauge theory. After briefly recalling some essential properties of centre\nvortices we point out that there is no known a priori connection between the\ngauge dependent P-vortices and the gauge invariant centre vortices. We then\nshow by Monte Carlo simulations that the `centre projected physics' strongly\ndepends on the gauge copy from which the maximal centre gauge fixing is\nstarted. This reveals the presence of Gribov problems, and casts some doubts on\nthe physical meaning of P-vortices, and should be further investigated.",
        "positive": "Clear Evidence of a Continuum Theory of 4D Euclidean Simplicial Quantum\n  Gravity: Four-dimensional (4D) simplicial quantum gravity coupled to both scalar\nfields (N_X) and gauge fields (N_A) has been studied using Monte-Carlo\nsimulations. The matter dependence of the string susceptibility exponent\ngamma^{(4)} is estimated. Furthermore, we compare our numerical results with\nBackground-Metric-Independent (BMI) formulation conjectured to describe the\nquantum field theory of gravity in 4D. The numerical results suggest that the\n4D simplicial quantum gravity is related to the conformal gravity in 4D.\nTherefore, we propose a phase structure in detail with adding both scalar and\ngauge fields and discuss the possibility and the property of a continuum theory\nof 4D Euclidean simplicial quantum gravity."
    },
    {
        "anchor": "Center vortex influence on the Dirac spectrum: We study the influence of center vortices on the low-lying eigenmodes of the\nDirac operator, in both the overlap and asqtad formulations. For\ncenter-projected configurations, one finds that the low-lying near-zero modes\nare present in the staggered (asqtad) formulation, but not in the overlap and\n\"chirally-improved\" formulations. We argue that this is due to the absence of a\nfield-independent chiral symmetry in the latter formulations, when the Dirac\noperator is evaluated on the very rough configurations generated by center\nprojection. We also confirm and extend the results of Kovalenko et al. [Phys.\nLett. B 648, 383 (2007)], finding strong correlations between center vortex\nlocations, and the scalar density of low-lying Dirac eigenmodes on unprojected\nlattices, in both asqtad and overlap formulations. It is found that the\nlow-lying eigenmodes have their largest concentrations in point-like regions,\nrather than on submanifolds of higher dimensionality.",
        "positive": "Leptonic decay-constant ratio $f_K/f_\u03c0$ from clover-improved $N_f=2+1$\n  QCD: The leptonic decay-constant ratio $f_K/f_\\pi$ is calculated from lattice-QCD\nsimulations using $N_f=2+1$ dynamical fermion flavors in the clover-improved\nformulation and 2-HEX smearing. The simulations were performed for a range of\nmass-degenerate light quarks including the physical point and at various\nlattice couplings and volumes, allowing to quantify all relevant sources of\nsystematic uncertainties for our final number of the decay-constant ratio.\nUtilizing input from chiral perturbation theory, we also quote the charged\ndecay-constant ratio $f_{K^\\pm}/f_{\\pi^\\pm}$. With further input from\nsuper-allowed nuclear $\\beta$-decays, eventually we obtain an estimate for the\nCKM-matrix element $V_{\\rm us}$."
    },
    {
        "anchor": "The quenched SU(2) fundamental scalar propagator in minimal Landau gauge: It is a long-standing question whether the confinement of matter fields in\nQCD has an imprint in the (gauge-dependent) correlation functions, especially\nthe propagators. As the analytic structure plays an important role in this\nquestion, high-precision data is necessary for lattice investigations. Also, it\nis interesting how this depends on the dimensionality of the theory. To make a\nstudy over a wide range of parameters possible this suggests to use scalar\nparticles. This is done here: The propagator of a fundamental scalar is studied\nin two, three, and four dimensions in quenched SU(2) Yang-Mills theory in\nminimal Landau gauge, both in momentum space and position space. Particular\nemphasis is put on the effects of renormalization. The results suggest a quite\nintricate volume dependence and the presence of an intrinsic mass scale, but no\nobvious connection to confinement.",
        "positive": "The eta and eta' mesons in QCD: We study the flavour singlet pseudoscalar mesons from first principles using\nlattice QCD. We explore the quark content of the $\\eta$ and $\\eta'$ mesons and\nwe discuss their decay constants."
    },
    {
        "anchor": "Nucleon charges with dynamical overlap fermions: We calculate the scalar and tensor charges of the nucleon in 2+1-flavor\nlattice QCD, for which the systematics of the renormalization of the\ndisconnected diagram is well controlled. Numerical simulations are performed at\na single lattice spacing a = 0.11 fm. We simulate four pion masses, which cover\na range of $m_\\pi \\sim$ 290 - 540 MeV, and a single strange quark mass close to\nits physical value. The statistical accuracy is improved by employing the\nso-called low-mode averaging technique and the truncated solver method. We\nstudy up, down, and strange quark contributions to the nucleon charges by\ncalculating disconnected diagrams using the all-to-all quark propagator. Chiral\nsymmetry is exactly preserved by using the overlap quark action to avoid\noperator mixing among different flavors, which complicates the renormalization\nof scalar and tensor matrix elements and leads to possibly large contamination\nto the small strange quark contributions. We also study the nucleon axial\ncharge with contribution from the disconnected diagram. Our results are in\nreasonable agreement with experiments and previous lattice studies.",
        "positive": "Alternative Numerical Techniques: Two new approaches to numerical QFT are presented."
    },
    {
        "anchor": "A new approach to significantly reduce the negative sign problem in\n  quantum Monte Carlo: We present a new approach for Monte Carlo simulations of lattice quantum spin\nsystems which is able to eliminate the negative sign problem. Its complexity is\nlinear in the volume of the lattice. Its efficiency is tested on a simple\n2-dimensional fermionic model.",
        "positive": "Complex $\\varphi^4$ Theory at Finite Temperature and Density via\n  Extended Mean Field Theory: We review the Extended Mean Field (EMFT) approximation and apply it to\ncomplex, scalar $\\varphi^4$ theory on the lattice. We determine the ($T,\\mu$)\nphase diagram and study the critical properties of the Bose condensation\ntransition, at zero and finite temperature. In both cases we obtain results\nwhich agree very well with recent Monte Carlo studies. Within our approximation\nwe can reach the thermodynamic limit and can thus obtain results at lattice\nspacings unreachable by present Monte Carlo simulations. We find that our\napproximation reproduces accurately many phenomena of the model, like the\n\"Silver Blaze\" behavior at zero temperature and dimensional reduction at finite\ntemperature."
    },
    {
        "anchor": "Indications of a non-trivial vacuum in the effective theory of perfect\n  fluids: Using lattice field theory techniques, we investigate the vacuum structure of\nthe field theory corresponding to perfect fluid dynamics in the Lagrangian\nprescription. We find intriguing, but inconclusive evidence, that the vacuum of\nsuch a theory is non-trivial, casting doubts on whether the gradient expansion\ncan provide a good effective field theory for this type of system. The\nnon-trivial vacuum looks like a \"turbulent\" state where some of the entropy is\ncarried by macroscopic degrees of freedom. We describe further steps to\nstrengthen or falsify this evidence.",
        "positive": "Strong coupling expansion of chiral models: A general precedure is outlined for an algorithmic implementation of the\nstrong coupling expansion of lattice chiral models on arbitrary lattices. A\nsymbolic character expansion in terms of connected values of group integrals on\nskeleton diagrams may be obtained by a fully computerized approach."
    },
    {
        "anchor": "Eigenvalues of the QCD Dirac matrix with improved staggered quarks in\n  the continuum limit: We calculate the eigenmodes of the Highly Improved Staggered Quark (HISQ)\nmatrix near the chiral crossover transition in QCD with $2+1$ flavors with the\naim to gain more insights into its temperature dependence. On performing the\ncontinuum extrapolation, we do not observe any gap opening up in the infrared\npart of the eigenvalue density of the QCD Dirac operator; instead we observe a\npeak. The existence of the peak and oscillations of the infrared eigenmodes can\nbe understood in terms of an interacting ensemble of instantons. From the\nproperties of the continuum extrapolated eigenspectrum we further show that the\nanomalous $U_A(1)$ part of the chiral symmetry is not effectively restored\nsimultaneously along with its non-singlet counterpart. We provide an\nexplanation for this observation, further showing interesting connections\nbetween the anomalous $U_A(1)$ restoration and the change in the infrared part\nof the eigenvalue distribution.",
        "positive": "Finite-size-scaling functions for 3d O(4) and O(2) spin models and QCD: We calculate numerically universal finite-size-scaling functions for the\nthree-dimensional O(4) and O(2) models. The approach of these functions to the\ninfinite-volume scaling functions is studied in detail on the critical and\npseudocritical lines. For this purpose we determine the pseudocritical line in\ntwo different ways. We find that the asymptotic form of the finite-size-scaling\nfunctions is already reached at small values of the scaling variable. A\ncomparison with QCD lattice data for two flavours of staggered fermions shows a\nsimilar finite-size behaviour which is compatible with that of the spin models."
    },
    {
        "anchor": "Two Loop Computation of a Running Coupling in Lattice Yang-Mills Theory: We compute the two loop coefficient in the relation between the lattice bare\ncoupling and the running coupling defined through the Schroedinger functional\nfor the case of pure SU(2) gauge theory. This result is needed as one\ncomputational component to relate the latter to the MSbar-coupling, and it\nallows us to implement O(a) improvement of the Schroedinger functional to\ntwo-loop order. In addition, the two-loop beta-function is verified in a\nperturbative computation on the lattice, and the behavior of an improved bare\ncoupling is investigated beyond one loop.",
        "positive": "B Physics with NRQCD: A Quenched Study: We present results on the spectrum of B mesons and heavy baryons, using a\nnon-relativistic formulation for the heavy and a clover action for the light\nquark. We also discuss B meson decay constants and their dependency upon the\nheavy meson mass."
    },
    {
        "anchor": "Scalar mesons and tetraquarks from twisted mass lattice QCD: We study light scalar mesons with particular focus on the a_0(980) using\nlattice QCD with 2+1+1 dynamical quark flavors. To investigate the structure of\nthese scalar mesons and to identify, whether a sizeable tetraquark component is\npresent, we use a large set of operators, including diquark-antidiquark,\nmesonic molecule and two-meson operators. We find that the low-lying states\noverlap essentially exclusively with two-meson states. This indicates that in\nthe channels investigated no tightly bound four-quark states of either\nmolecular or diquark-antidiquark type exist.",
        "positive": "Hyperon and charmed baryon masses and nucleon excited states from\n  lattice QCD: We discuss the status of current dynamical lattice QCD simulations in\nconnection to the emerging results on the strange and charmed baryon spectrum,\nexcited states of the nucleon and the investigation of the structure of scalar\nmesons."
    },
    {
        "anchor": "Light-quark connected intermediate-window contributions to the muon\n  $g-2$ hadronic vacuum polarization from lattice QCD: We present a lattice-QCD calculation of the light-quark connected\ncontribution to window observables associated with the leading-order hadronic\nvacuum polarization contribution to the anomalous magnetic moment of the muon,\n$a_\\mu^{\\mathrm{HVP,LO}}$. We employ the MILC Collaboration's isospin-symmetric\nQCD gauge-field ensembles, which contain four flavors of dynamical\nhighly-improved-staggered quarks with four lattice spacings between $a\\approx\n0.06$-$0.15$~fm and close-to-physical quark masses. We consider several\neffective-field-theory-based schemes for finite-volume and other lattice\ncorrections and combine the results via Bayesian model averaging to obtain\nrobust estimates of the associated systematic uncertainties. After unblinding,\nour final results for the intermediate and ``W2'' windows are $a^{ll,{\\mathrm\nW}}_{\\mu}(\\mathrm{conn.})=206.6(1.0) \\times 10^{-10}$ and $a^{ll,\\mathrm\n{W2}}_{\\mu}(\\mathrm{conn.}) = 100.7(3.2)\\times 10^{-10}$, respectively.",
        "positive": "Discretization Errors and Rotational Symmetry: The Laplacian Operator on\n  Non-Hypercubical Lattices: Discretizations of the Laplacian operator on non-hypercubical lattices are\ndiscussed in a systematic approach. It is shown that order $a^2$ errors always\nexist for discretizations involving only nearest neighbors. Among all lattices\nwith the same density of lattice sites, the hypercubical lattices always have\nerrors smaller than other lattices with the same number of spacetime\ndimensions. On the other hand, the four dimensional checkerboard lattice (also\nknown as the Celmaster lattice) is the only lattice which is isotropic at order\n$a^2$. Explicit forms of the discretized Laplacian operators on root lattices\nare presented, and different ways of eliminating order $a^2$ errors are\ndiscussed."
    },
    {
        "anchor": "Lattice simulations of the QCD chiral transition at real $\u03bc_B$: Most lattice studies of hot and dense QCD matter rely on extrapolation from\nzero or imaginary chemical potentials. The ill-posedness of numerical analytic\ncontinuation puts severe limitations on the reliability of such methods. We\nstudied the QCD chiral transition at finite real baryon density with the more\ndirect sign reweighting approach. We simulate up to a baryochemical\npotential-temperature ratio of $\\mu_B/T=2.7$, covering the RHIC Beam Energy\nScan range, and penetrating the region where methods based on analytic\ncontinuation are unpredictive.This opens up a new window to study QCD matter at\nfinite $\\mu_B$ from first principles.",
        "positive": "Comment on the subtlety of defining real-time path integral in lattice\n  gauge theories: Recently, Hoshina, Fujii, and Kikukawa pointed out that the naive lattice\ngauge theory action in Minkowski signature does not result in a unitary theory\nin the continuum limit, and Kanwar and Wagman proposed alternative lattice\nactions to the Wilson action without divergences. We here show that the\nsubtlety can be understood from the asymptotic expansion of the modified Bessel\nfunction, which has been discussed for path integral of compact variables in\nnonrelativistic quantum mechanics. The essential ingredient for defining the\nappropriate continuum theory is the $i\\varepsilon$ prescription, and with the\nproper implementation of the $i\\varepsilon$ we show that the Wilson action can\nbe used for the real-time path integrals. It is here important that the\n$i\\varepsilon$ should be implemented for both timelike and spacelike\nplaquettes. We also argue the reason why the $i\\varepsilon$ becomes required\nfor the Wilson action from the Hamiltonian formalism. The $i\\varepsilon$ is\nneeded to manifestly suppress the contributions from singular paths, for which\nthe Wilson action can give different values from those of the actual continuum\naction."
    },
    {
        "anchor": "Lattice study on chiral dynamics of two-color six-flavors QCD: The electroweak symmetry breaking and origin of masses may be attributed to\nthe breakdown of chiral symmetry due to a strong gauge dynamics. Among several\ncandidates of such gauge systems, we focus on two-color QCD with $N_f=6$\nmassless Dirac fermions in the fundamental representation, and study on whether\nthe dynamics of this gauge system trigger chiral symmetry breaking or not by\nsimulating with Wilson fermions on lattices up to $L/a=32$. We show the result\nfor the quark mass dependence and the volume dependence of some quantities such\nas the mass of the lightest pseudoscalar meson, decay constant, and give the\nthree evidences supporting the absence of chiral symmetry breaking in the\nsix-flavor theory.",
        "positive": "Gradient flow step-scaling function for SU(3) with ten fundamental\n  flavors: We calculate the step scaling function, the lattice analog of the\nrenormalization group $\\beta$-function, for an SU(3) gauge theory with ten\nfundamental flavors. We present a detailed analysis including the study of\nsystematic effects of our extensive data set generated with ten dynamical\nflavors using the Symanzik gauge action and three times stout smeared M\\\"obius\ndomain wall fermions. Using up to $32^4$ volumes, we calculate renormalized\ncouplings for different gradient flow schemes and determine the step-scaling\n$\\beta$ function for a scale change $s=2$ on up to five different lattice\nvolume pairs. In an accompanying paper we discuss that gradient flow can\npromote lattice dislocations to instanton-like objects, introducing\nnonperturbative lattice artifacts to the step scaling function. Motivated by\nthe observation that Wilson flow sufficiently suppresses these artifacts, we\nchoose Wilson flow with the Symanzik operator as our preferred analysis. We\nstudy systematic effects by calculating the step-scaling function based on\nalternative flows (Zeuthen or Symanzik), alternative operators (Wilson\nplaquette, clover), and also explore the effects of the perturbative tree-level\nimprovement. Further we investigate the effects due to the finite value of\n$L_s$."
    },
    {
        "anchor": "The three-particle system on a torus: Based on Lippmann-Schwinger equation approach, we discuss a three-particle\nsystem in finite volume. A set of equations which relate the discrete\nfinite-volume energies to the scattering amplitudes are derived under the\napproximation of the isobar model relevant for the case of narrow two- and\nthree-body resonances.",
        "positive": "Nucleon-Nucleon Interactions on the Lattice: We consider the nucleon-nucleon potential in quenched and partially-quenched\nQCD. The leading one-meson exchange contribution to the potential is found to\nfall off exponentially at long-distances, in contrast with the Yukawa-type\nbehaviour found in QCD. This unphysical component of the two-nucleon potential\nhas important implications for the extraction of nuclear properties from\nlattice simulations."
    },
    {
        "anchor": "An estimate of the chiral condensate from unquenched lattice QCD: Using the parameters in the chiral Lagrangian obtained by MILC from their\nunquenched lattice QCD calculations with 2+1 flavours of sea quarks, I estimate\n<psi_bar psi> (2 GeV)/n_f = -(259 \\pm 27 MeV)**3 in the MS_bar scheme. I\ncompare this value to other determinations.",
        "positive": "Central Dominance and the Confinement Mechanism in Gluodynamics: New topological objects, which we call center monopoles, naturally arise in\nthe Maximal Center Projection of SU(3) gluodynamics. The condensate of the\ncenter monopoles is the order parameter of the theory."
    },
    {
        "anchor": "Lattice Approach to Diquark Condensation in Dense Matter: Results are presented of a Monte Carlo simulation of a 2+1 dimensional\nGross-Neveu model with SU(2)xSU(2) chiral symmetry at non-zero baryon chemical\npotential, corresponding to non-zero baryon density. The phenomenon of quark\npair condensation is sought via measurement of a two point function. For\nsufficiently large chemical potential there is a sharp transition between a\nphase where the chiral symmetry is broken by a standard chiral condensate and\none where a scalar diquark condensate, qq, is non-zero. Global U(1) baryon\nnumber symmetry may remain unbroken, however, due to the absence of long range\norder in the phase of qq.",
        "positive": "Towards a lattice calculation of the coefficients of the QCD chiral\n  Lagrangian: We discuss a general strategy to compute the coefficients of QCD chiral\nLagrangian by using the lattice regularization of QCD with Wilson fermions.\nThis procedure requires the introduction of an effective Lagrangian for lattice\nQCD as an intermediate step in the calculation. The continuum QCD chiral\nLagrangian can be then obtained by expanding the lattice effective Lagrangian\nin increasing powers of the external momenta. A suitable renormalization\nprocedure is required to account for the chiral symmetry breaking introduced by\nthe Wilson term in the lattice action. In anticipation of a numerical\nsimulation, the lattice effective Lagrangian is computed analytically and\ninvestigated in the strong coupling and large $N$ limit"
    },
    {
        "anchor": "Hamiltonian Flow of Yang-Mills Theory in Coulomb Gauge: A new functional renormalization group equation for Hamiltonian Yang-Mills\ntheory in Coulomb gauge is presented and solved for the static gluon and ghost\npropagators under the assumption of ghost dominance. The results are compared\nto those obtained in the variational approach.",
        "positive": "The emergence of expanding space-time in a novel large-$N$ limit of the\n  Lorentzian type IIB matrix model: The Lorentzian type IIB matrix model is a promising candidate for a\nnon-perturbative formulation of superstring theory. However, it was found\nrecently that a Euclidean space-time appears in the conventional large-$N$\nlimit. In this work, we add a Lorentz invariant mass term to the original model\nand consider a limit, in which the coefficient of the mass term vanishes at\nlarge $N$. By performing complex Langevin simulations to overcome the sign\nproblem, we observe the emergence of expanding space-time with the Lorentzian\nsignature."
    },
    {
        "anchor": "Lattice QCD study on $K^\\ast(892)$ meson decay width: We deliver an exploratory lattice QCD examination of the $K^\\ast(892)$ meson\ndecay width with the help of the p-wave scattering phase $\\delta_1$ of\npion-kaon ($\\pi K$) system in the isospin $I=1/2$ channel, which are extracted\nby the modified Rummukainen-Gottlieb formula for two-particle system with\narbitrary mass, and it clearly reveals the entity of a resonance at a mass\naround $K^\\ast(892)$ meson mass. The effective range formula is applied to\ndescribe the energy dependence of the scattering phase and we obtain the\neffective $K^\\ast \\to \\pi K$ coupling constant as $g_{K^\\ast \\pi K} =\n6.38(78)$, and subsequently achieve the decay width to be $64.9 \\pm 8.0$ MeV,\nwhich is in reasonable accordance with the current experiment. Our lattice\ninvestigations are conducted on a $20^3\\times48$ MILC full QCD gauge\nconfiguration at $(m_\\pi + m_K) / m_{K^\\ast} \\approx 0.739$ and the lattice\nspacing $a \\approx 0.15$ fm.",
        "positive": "Simulating Simplified Versions of the IKKT Matrix Model: We simulate a supersymmetric matrix model obtained from dimensional reduction\nof 4d SU(N) super Yang-Mills theory (a 4d counter part of the IKKT model or IIB\nmatrix model). The eigenvalue distribution determines the space structure. The\nmeasurement of Wilson loop correlators reveals a universal large N scaling.\nEguchi-Kawai equivalence may hold in a finite range of scale, which is also\ntrue for the bosonic case. We finally report on simulations of a low energy\napproximation of the 10d IKKT model, where we omit the phase of the Pfaffian\nand look for evidence for a spontaneous Lorentz symmetry breaking."
    },
    {
        "anchor": "Radial Quantization for Conformal Field Theories on the Lattice: We consider radial quantization for conformal quantum field theory with a\nlattice regulator. A Euclidean field theory on $\\mathbb R^D$ is mapped to a\ncylindrical manifold, $\\mathbb R\\times \\mathbb S^{D-1}$, whose length is\nlogarithmic in scale separation. To test the approach, we apply this to the 3D\nIsing model and compute $\\eta$ for the first $Z_2$ odd primary operator.",
        "positive": "Schroedinger functional formalism for overlap Dirac operator and\n  domain-wall fermion: In this proceeding we propose a new procedure to impose the Schroedinger\nfunctional Dirichlet boundary condition on the overlap Dirac operator and the\ndomain-wall fermion using an orbifolding projection.\n  With this procedure the zero mode problem with Dirichlet boundary condition\ncan easily be avoided."
    },
    {
        "anchor": "Finite Temperature Transition in Two Flavor QCD with Renormalization\n  Group Improved Action: The finite temperature transition or crossover in QCD with two degenerate\nWilson quarks is investigated using a renormalization group improved action. At\n$\\beta=2.0$ and 2.1 where $a^{-1} \\sim 1.0-1.2$ GeV, the expectation value of\nthe Polyakov loop and the pion screening mass on an $8^3 \\times 4$ lattice vary\nsmoothly with the hopping parameter through the transition/crossover. The quark\nscreening mass in the high temperature phase agrees well with that in the low\ntemperature phase calculated on an $8^4$ lattice. The smooth transition of the\nobservables is totally different from the sharp transition found for the\nstandard action at $\\beta=5.0$ and 5.1 where $a^{-1}$ is also $1.0-1.2$ GeV.",
        "positive": "Flavor Twisted Boundary Conditions and the Nucleon Vector Current: Using flavor twisted boundary conditions, we study nucleon matrix elements of\nthe vector current. We twist only the active quarks that couple to the current.\nFinite volume corrections due to twisted boundary conditions are determined\nusing partially twisted, partially quenched, heavy baryon chiral perturbation\ntheory, which we develop for the graded group SU(7|5). Asymptotically these\ncorrections are exponentially small in the volume, but can become pronounced\nfor small twist angles. Utilizing the Breit frame does not mitigate volume\ncorrections to nucleon vector current matrix elements. The derived expressions\nwill allow for better controlled extractions of the isovector magnetic moment\nand the electromagnetic radii from simulations at zero lattice momentum. Our\nformalism, moreover, can be applied to any nucleon matrix elements."
    },
    {
        "anchor": "Chiral fermion on curved domain-wall: We consider a massive fermion system having a curved domain-wall embedded in\na square lattice. In a similar way to the conventional flat domain-wall\nfermion, chiral massless modes appear at the domain-wall but these modes feel\n\"gravity\" through the induced spin connections. In this work, we embed $S^1$\nand $S^2$ domain-walls into a Euclidean space and show how the gravity is\ndetected from the spectrum of the Dirac operator.",
        "positive": "Renormalization of heavy-light currents in moving NRQCD: Heavy-light decays such as $B \\to \\pi \\ell \\nu$, $B \\to K^{*} \\gamma$ and $B\n\\to K^{(*)} \\ell \\ell$ can be used to constrain the parameters of the Standard\nModel and in indirect searches for new physics. While the precision of\nexperimental results has improved over the last years this has still to be\nmatched by equally precise theoretical predictions. The calculation of\nheavy-light form factors is currently carried out in lattice QCD. Due to its\nsmall Compton wavelength we discretize the heavy quark in an effective\nnon-relativistic theory. By formulating the theory in a moving frame of\nreference discretization errors in the final state are reduced at large recoil.\nOver the last years the formalism has been improved and tested extensively.\nSystematic uncertainties are reduced by renormalizing the m(oving)NRQCD action\nand heavy-light decay operators. The theory differs from QCD only for large\nloop momenta at the order of the lattice cutoff and the calculation can be\ncarried out in perturbation theory as an expansion in the strong coupling\nconstant. In this paper we calculate the one loop corrections to the\nheavy-light vector and tensor operator. Due to the complexity of the action the\ngeneration of lattice Feynman rules is automated and loop integrals are solved\nby the adaptive Monte Carlo integrator VEGAS. We discuss the infrared and\nultraviolet divergences in the loop integrals both in the continuum and on the\nlattice. The light quarks are discretized in the ASQTad and highly improved\nstaggered quark (HISQ) action; the formalism is easily extended to other quark\nactions."
    },
    {
        "anchor": "Why rooting fails: I explore the origins of the unphysical predictions from rooted staggered\nfermion algorithms. Before rooting, the exact chiral symmetry of staggered\nfermions is a flavored symmetry among the four \"tastes.\" The rooting procedure\naverages over tastes of different chiralities. This averaging forbids the\nappearance of the correct 't Hooft vertex for the target theory.",
        "positive": "Interpreting machine learning functions as physical observables: We propose to interpret machine learning functions as physical observables,\nopening up the possibility to apply \"standard\" statistical-mechanical methods\nto outputs from neural networks. This includes histogram reweighting and\nfinite-size scaling, to analyse phase transitions quantitatively. In addition\nwe incorporate predictive functions as conjugate variables coupled to an\nexternal field within the Hamiltonian of a system, allowing to induce\norder-disorder phase transitions in a novel manner. A noteworthy feature of\nthis approach is that no knowledge of the symmetries in the Hamiltonian is\nrequired."
    },
    {
        "anchor": "Phase Transitions at Finite Temperature and Dimensional Reduction for\n  Fermions and Bosons: In a recent Letter we discussed the fact that large-$N$ expansions and\ncomputer simulations indicate that the universality class of the finite\ntemperature chiral symmetry restoration transition in the 3D Gross-Neveu model\nis mean field theory. This was seen to be a counterexample to the standard\n'sigma model' scenario which predicts the 2D Ising model universality class. In\nthis article we present more evidence, both theoretical and numerical, that\nthis result is correct. We develop a physical picture for our results and\ndiscuss the width of the scaling region (Ginzburg criterion), $1/N$\ncorrections, and differences between the dynamics of BCS superconductors and\nGross-Neveu models. Lattices as large as $12 \\times 72^2$ are simulated for\nboth the $N=12$ and $N=4$ cases and the numerical evidence for mean field\nscaling is quite compelling. We point out that the amplitude ratio for the\nmodel's susceptibility is a particulartly good observable for distinguishing\nbetween the dimensional reduction and the mean field scenerios, because this\nuniversal quantity differs by almost a factor of $20$ in the two cases. The\nsimulations are done close to the critical point in both the symmetric and\nbroken phases, and correlation lengths of order $10$ are measured. The critical\nindices $\\beta_{mag}$ and $\\delta$ also pick out mean field behavior. We trace\nthe breakdown of the standard scenario (dimensional reduction and universality)\nto the composite character of the mesons in the model. We point out that our\nresults should be generic for theories with dynamical symmetry breaking, such\nas Quantum Chromodynamics.\n  We also simulated the $O(2)$ model on $8 \\times 16^3$ lattices to establish\nthat our methods give the results of dimensional reduction in purely bosonic",
        "positive": "Exotic Meson Decay Widths using Lattice QCD: A decay width calculation for a hybrid exotic meson h, with JPC=1-+, is\npresented for the channel h->pi+a1. This quenched lattice QCD simulation\nemploys Luescher's finite box method. Operators coupling to the h and pi+a1\nstates are used at various levels of smearing and fuzzing, and at four quark\nmasses. Eigenvalues of the corresponding correlation matrices yield energy\nspectra that determine scattering phase shifts for a discrete set of relative\npi+a1 momenta. Although the phase shift data is sparse, fits to a Breit-Wigner\nmodel are attempted, resulting in a decay width of about 60 MeV when averaged\nover two lattice sizes."
    },
    {
        "anchor": "Two-dimensional model of dynamical fermion mass generation in strongly\n  coupled gauge theories: We generalize the $N_F=2$ Schwinger model on the lattice by adding a charged\nscalar field. In this so-called $\\chi U\\phi_2$ model the scalar field shields\nthe fermion charge, and a neutral fermion, acquiring mass dynamically, is\npresent in the spectrum. We study numerically the mass of this fermion at\nvarious large fixed values of the gauge coupling by varying the effective\nfour-fermion coupling, and find an indication that its scaling behavior is the\nsame as that of the fermion mass in the chiral Gross-Neveu model. This suggests\nthat the $\\chi U\\phi_2$ model is in the same universality class as the\nGross-Neveu model, and thus renormalizable and asymptotic free at arbitrary\nstrong gauge coupling.",
        "positive": "Dynamical Triangulation with Fluctuating Topology: We consider a dynamical triangulation model of euclidean quantum gravity\nwhere the topology is not fixed. This model is equivalent to a tensor\ngeneralization of the matrix model of two dimensional quantum gravity. A set of\nmoves is given that allows Monte Carlo simulation of this model. Some\npreliminary results are presented for the case of four dimensions."
    },
    {
        "anchor": "Simulations with Complex Measures: Towards a solution to the sign problem in the simulations of systems having\nindefinite or complex-valued measures, we propose a new approach which yields\nstatistical errors smaller than the crude Monte Carlo using absolute values of\nthe original measures. The 1D complex-coupling Ising model is employed as an\nillustration.",
        "positive": "Progress on the exploratory calculation of the rare Hyperon decay\n  $\u03a3^+ \\to p \\ell^+ \\ell^-$: The rare Hyperon decay $\\Sigma^+ \\to p \\ell^+ \\ell^-$ is an $s \\to d$ flavour\nchanging neutral current process, which is highly suppressed within the\nStandard Model, and is therefore sensitive to new physics. Due to recent\nimprovements in experimental measurements of this decay, the Standard Model\ntheory prediction must also be improved in order to identify any new physics in\nthis channel. We present updates on our progress towards the first exploratory\nlattice calculation of the long-distance part of the form factors of this\ndecay. This pilot calculation is performed on a 340 MeV pion mass ensemble\nusing domain-wall fermions as part of the RBC-UKQCD collaboration."
    },
    {
        "anchor": "Symmetries and exponential error reduction in Yang-Mills theories on the\n  lattice: The partition function of a quantum field theory with an exact symmetry can\nbe decomposed into a sum of functional integrals each giving the contribution\nfrom states with definite symmetry properties. The composition rules of the\ncorresponding transfer matrix elements can be exploited to devise a multi-level\nMonte Carlo integration scheme for computing correlation functions whose\nnumerical cost, at a fixed precision and at asymptotically large times,\nincreases power-like with the time extent of the lattice. As a result the\nnumerical effort is exponentially reduced with respect to the standard Monte\nCarlo procedure. We test this strategy in the SU(3) Yang--Mills theory by\nevaluating the relative contribution to the partition function of the parity\nodd states.",
        "positive": "Theoretical aspects of quantum electrodynamics in a finite volume with\n  periodic boundary conditions: First-principles studies of strongly-interacting hadronic systems using\nlattice quantum chromodynamics (QCD) have been complemented in recent years\nwith the inclusion of quantum electrodynamics (QED). The aim is to confront\nexperimental results with more precise theoretical determinations, e.g. for the\nanomalous magnetic moment of the muon and the CP-violating parameters in the\ndecay of mesons. Quantifying the effects arising from enclosing QED in a finite\nvolume remains a primary target of investigations. To this end, finite-volume\ncorrections to hadron masses in the presence of QED have been carefully studied\nin recent years. This paper extends such studies to the self-energy of moving\ncharged hadrons, both on and away from their mass shell. In particular, we\npresent analytical results for leading finite-volume corrections to the\nself-energy of spin-0 and spin-$\\frac{1}{2}$ particles in the presence of QED\non a periodic hypercubic lattice, once the spatial zero mode of the photon is\nremoved, a framework that is called $\\mathrm{QED}_{\\mathrm{L}}$. By altering\nmodes beyond the zero mode, an improvement scheme is introduced to eliminate\nthe leading finite-volume corrections to masses, with potential applications to\nother hadronic quantities. Our analytical results are verified by a dedicated\nnumerical study of a lattice scalar field theory coupled to\n$\\mathrm{QED}_{\\mathrm{L}}$. Further, this paper offers new perspectives on the\nsubtleties involved in applying low-energy effective field theories in the\npresence of $\\mathrm{QED}_{\\mathrm{L}}$, a theory that is rendered non-local\nwith the exclusion of the spatial zero mode of the photon, clarifying recent\ndiscussions on this matter."
    },
    {
        "anchor": "Discrete non-Abelian groups and asymptotically free models: We consider a two-dimensional $\\sigma$-model with discrete\nicosahedral/dodecahedral symmetry. Using the perturbative renormalization\ngroup, we argue that this model has a different continuum limit with respect to\nthe O(3) $\\sigma$ model. Such an argument is confirmed by a high-precision\nnumerical simulation.",
        "positive": "Finite Size Scaling and Universality in SU(2) at Finite Temperature: We study the 4-th Binder cumulant on $4\\times{N_\\sigma}^3$ lattices for a\npure SU(2) gauge theory. We use 20 data points for a sequence of ${N_\\sigma}$\nin $\\beta$ intervals shrinking when ${N_\\sigma}$ increases, in order to reduce\nthe nonlinear effects. Using a log-log fit of the slope versus ${N_\\sigma}$, we\nobtain the preliminary result $\\nu=0.637(11)$ in reasonably good agreement with\nthe value for the 3D Ising model universality class. The corrections due to\nirrelevant directions appear to be dominated by a term proportional to\n${N_\\sigma}^{-2.03(4)}$ which seems compatible with the breaking of rotational\nsymmetry."
    },
    {
        "anchor": "CP symmetry and lattice chiral gauge theories: The CP symmetry is a fundamental discrete symmetry in chiral gauge theory.\nTherefore this symmetry is expected to be kept also on the lattice. However, it\nhas been pointed out by Hasenfratz that the chiral fermion action in Luscher's\nformulation of lattice chiral gauge theory is not invariant under CP\ntransformation. In this thesis, we first review the method of constructing\nchiral gauge theory on the lattice. Then we generalize the analysis of\nHasenfratz and show that CP symmetry is not manifestly implemented for the\nlocal and doubler-free Ginsparg-Wilson operator under rather general\nassumptions for chiral projection operators. We next calculate the fermion\ngenerating functional and precisely identify where the effects of this CP\nbreaking appear in this formulation. The basics of lattice gauge theory are\nbriefly summarized in Appendix.A.",
        "positive": "Discovering new physics in rare kaon decays: The decays and mixing of $K$ mesons are remarkably sensitive to the weak\ninteractions of quarks and leptons at high energies. They provide important\ntests of the standard model at both first and second order in the Fermi\nconstant $G_F$ and offer a window into possible new phenomena at energies as\nhigh as 1,000 TeV. These possibilities become even more compelling as the\ngrowing capabilities of lattice QCD make high-precision standard model\npredictions possible. Here we discuss and attempt to forecast some of these\ncapabilities."
    },
    {
        "anchor": "The critical end point of quantum chromodynamics: We investigate the critical end point (CEP) of QCD with\n  two flavours of light dynamical quarks at finite lattice cutoff\n  a=1/4T using a Taylor expansion of the baryon number\n  susceptibility. We find a strong volume dependence of the position\n  of the critical end point. In the large volume limit we obtain\\\n  T^E/T_c approximately 0.95 and mu_B^E/T^E approximately 1.1, where T_c is\n  the cross over temperature at zero chemical potential, and T^E\n  and mu_B^E are the temperature and the baryon chemical potential\n  at the critical end point. The small value of mu_B^E places it\n  in the range of observability in energy scans at the RHIC.",
        "positive": "Simulation of SU(2) Dynamical Fermion at Finite Chemical Potential and\n  at Finite Temperature: SU(2) lattice gauge theory with dynamical fermion at non-zero chemical\npotential and at finite temperature is studied. We focus on the influence of\nchemical potential for quark condensate and mass of pseudoscalar meson at\nfinite temperature.\n  Hybrid Monte Carlo simulations with $N_f=8$ staggered fermions are carried\nout on $12 \\times 12\\times 24 \\times 4$ lattice. At $\\beta=1.1$ and\n$m_{q}=$0.05,0.07,0.1, we calculate the quark condensate and masses of\npseudoscalar meson consisting of light and heavier quarks for chemical\npotential $\\mu=$ 0.0,0.02,0.05,0.1,0.2."
    },
    {
        "anchor": "Scattering amplitude from Bethe-Salpeter wave function inside the\n  interaction range: We propose a method to calculate scattering amplitudes using the\nBethe-Salpeter wave function inside the interaction range on the lattice. For\nan exploratory study of this method, we evaluate a scattering length of $I=2$\nS-wave two pions by the use of the on-shell scattering amplitude. Our result is\nconfirmed to be consistent with the value obtained from the conventional finite\nvolume method. The half-off-shell scattering amplitude is also evaluated.",
        "positive": "Rigorous arguments against current wisdoms in finite density QCD: QCD at finite chemical potential is analytically investigated in the region\nof large bare fermion masses. We show that, contrary to the general wisdom, the\nphase of the fermion determinant is irrelevant at zero temperature. However if\nthe system is put at finite temperature, the contribution of the phase is\nfinite. We also discuss on the quenched approximation and suggest that the\norigin of the failure of this approximation in finite density QCD could relay\non the fundamental role that Pauli exclusion principle plays in this case."
    },
    {
        "anchor": "Relations between the Gribov-horizon and center-vortex confinement\n  scenarios: We review numerical evidence on connections between the center-vortex and\nGribov-horizon confinement scenarios.",
        "positive": "Chiral phase transition as an Anderson transition in the Instanton\n  Liquid Model for QCD: We study the spectrum and eigenmodes of the QCD Dirac operator in a gauge\nbackground given by an Instanton Liquid Model (ILM) at temperatures around the\nchiral phase transition. For two massless quark flavors we observe that at the\nchiral phase transition, both the low lying eigenmodes and the spectrum of the\nQCD Dirac operator resemble those of a disordered conductor at the Anderson\ntransition. In particular we present results showing that the eigenvectors are\nmultifractal and the spectral correlations are well described by critical\nstatistics. We also find an additional temperature dependent mobility edge\nlocated in the bulk of the spectrum with properties quantitatively similar to\nthose of a 3D disordered conductor at the Anderson transition. This feature is\npresent in both quenched and unquenched simulations. Finally we argue that our\nfindings are not in principle restricted to the ILM approximation and may also\nbe found in lattice simulations."
    },
    {
        "anchor": "On the Locality and Scaling of Overlap Fermions at Coarse Lattice\n  Spacings: The overlap fermion offers the considerable advantage of exact chiral\nsymmetry on the lattice, but is numerically intensive. This can be made\naffordable while still providing large lattice volumes, by using coarse lattice\nspacing, given that good scaling and localization properties are established.\nHere, using overlap fermions on quenched Iwasaki gauge configurations, we\ndemonstrate directly that, with appropriate choice of negative Wilson's mass,\nthe overlap Dirac operator's range is comfortably small in lattice units for\neach of the lattice spacings 0.20 fm, 0.17 fm, and 0.13 fm (and scales to zero\nin physical units in the continuum limit). In particular, our direct results\ncontradict recent speculation that an inverse lattice spacing of 1 GeV is too\nlow to have satisfactory localization. Furthermore, hadronic masses (available\non the two coarser lattices) scale very well.",
        "positive": "Volume Effects for Pion Two-Point Functions in Constant Electric and\n  Magnetic Fields: We compute finite volume effects relevant for lattice QCD simulations using\nbackground fields. Focusing on constant electric and magnetic fields on a\nperiodic lattice, we determine volume corrections to pion two-point functions\nusing chiral perturbation theory. Among such corrections are the finite volume\nshifts to the electric and magnetic polarizabilities, which are numerically\nshown to be non-negligible. We additionally find that all terms in the\nsingle-particle effective action can be renormalized by infrared effects. This\nincludes Born couplings to the pion current and total charge-squared, which can\nbe renormalized due to the nature of gauge invariance on a torus."
    },
    {
        "anchor": "Leptonic Decays of Heavy-Light Systems: Results from recent lattice calculations of the decay constants $f_B$ and\n$f_D$ are reviewed. A discussion of the methods currently used is presented,\ntogether with an outline of the various systematic effects involved.",
        "positive": "Physics of eta-prime with rooted staggered quarks: The quark-mass dependence of the eta in the Schwinger model, which -- like\nthe eta-prime in QCD -- becomes massive through the axial anomaly, is studied\non the lattice with N_f=0,1,2. Staggered quarks are used, with a rooted\ndeterminant for N_f=1. In the chiral limit the Schwinger mass is reproduced,\nwhich suggests that the anomaly is being treated correctly."
    },
    {
        "anchor": "Phase Structure of the 5D Abelian Higgs Model with Anisotropic Couplings: We establish the phase diagram of the five-dimensional anisotropic Abelian\nHiggs model by mean field techniques and Monte Carlo simulations. The\nanisotropy is encoded in the gauge couplings as well as in the Higgs couplings.\nIn addition to the usual bulk phases (confining, Coulomb and Higgs) we find\nfour-dimensional ``layered'' phases (3-branes) at weak gauge coupling, where\nthe layers may be in either the Coulomb or the Higgs phase, while the\ntransverse directions are confining.",
        "positive": "Topological Structure in the SU(2) Vacuum: We study the topological content of the vacuum of SU(2) pure gauge theory\nusing lattice simulations. We use a smoothing process based on the\nrenormalization group equation which removes short distance fluctuations but\npreserves long distance structure. The action of the smoothed configurations is\ndominated by instantons, but they still show an area law for Wilson loops with\na string tension equal to the string tension on the original configurations.\nYet it appears that instantons are not directly responsible for confinement.\nThe average radius of an instanton is about 0.2 fm, at a density of about 2\nfm^(-4). This is a much smaller average size than other lattice studies have\nindicated. The instantons appear not to be randomly distributed in space, but\nare clustered."
    },
    {
        "anchor": "Single static-quark system above $T_c$ investigated by energy-momentum\n  tensor in SU(3) Yang-Mills theory: We investigate the distribution of energy-momentum tensor (EMT) around a\nstatic quark in the deconfined phase of SU(3) Yang-Mills theory. The EMT\ndefined through the gradient-flow formalism is used for the numerical analysis\nof the EMT distribution around the Polyakov loop with the continuum\nextrapolation. Using EMT, one can study the mechanical distortion of the color\ngauge field induced by the static charge. We find substantial separation in the\nabsolute values of the EMT eigenvalues which is not observed in Maxwell theory.\nThe separation grows as temperature is lowered toward the critical temperature.\nThe lattice data also indicate the thermal screening at long distance and the\nperturbative behavior at short distance.",
        "positive": "An Abelian two-Higgs model and high temperature superconductivity: We study a three dimensional Abelian Higgs model containing singly- and\ndoubly-charged scalar fields coupled to a compact Abelian gauge field in the\nLondon limit. The model attracts interest because of its relevance to high-Tc\nsuperconductors with charge 1 holon and charge 2 spinon-pair fields. It\ncontains two types of vortices carrying magnetic flux and one type of\ninstanton-like monopoles. Using thermodynamic and topological observables we\npresent the phase diagram in the parameter space of the gauge and holon and\nspinon-pair couplings. The Fermi liquid, the spin gap, the superconductor and\nthe strange metallic phases have been identified in a wide region of\nparameters. The model may serve as a toy system modelling non-perturbative\nproperties of the Yang-Mills theory."
    },
    {
        "anchor": "DDalphaAMG for Twisted Mass Fermions: We present the Adaptive Aggregation-based Domain Decomposition Multigrid\nmethod extended to the twisted mass fermion discretization action. We show\ncomparisons of results as a function of tuning the parameters that enter the\ntwisted mass version of the DDalphaAMG library\n(https://github.com/sbacchio/DDalphaAMG). Moreover, we linked the DDalphaAMG\nlibrary to the tmLQCD software package and give details on the performance of\nthe multigrid solver during HMC simulations at the physical point.",
        "positive": "Heavy Quark Physics: Lattice calculations of heavy quark systems provide very good measures of the\nlattice spacing, a key element in recent determinations of the strong coupling\nconstant using lattice methods. They also provide excellent testing grounds for\nlattice methods in general. I review recent phenomenological and technical\ndevelopments in this field."
    },
    {
        "anchor": "The density of states method at non-zero chemical potential: We study the QCD phase diagram by first principle lattice calculations at so\nfar unreached high densities. For this purpose we employ the density of states\nmethod. Unimproved staggered fermions, which describe four quark flavors in the\ncontinuum are used in this analysis. Though the method is quite expensive,\nsmall lattices show an indication for a triple-point connecting three different\nphases on the phase diagram.",
        "positive": "Unitarized Chiral Perturbation Theory in a finite volume: scalar meson\n  sector: We develop a scheme for the extraction of the properties of the scalar mesons\nf0(600), f0(980), and a0(980) from lattice QCD data. This scheme is based on a\ntwo-channel chiral unitary approach with fully relativistic propagators in a\nfinite volume. In order to discuss the feasibility of finding the mass and\nwidth of the scalar resonances, we analyze synthetic lattice data with a fixed\nerror assigned, and show that the framework can be indeed used for an accurate\ndetermination of resonance pole positions in the multi-channel scattering."
    },
    {
        "anchor": "Quark-gluon plasma phenomenology from the lattice: The FASTSUM Collaboration has calculated several quantities relevant for QCD\nstudies at non-zero temperature using the lattice technique. We report here our\nresults for the (i) interquark potential in charmonium; (ii) bottomonium\nspectral functions; and (iii) electrical conductivity. All results were\nobtained with 2+1 flavours of dynamical fermions on an anisotropic lattice\nwhich allows greater resolution in the temporal direction.",
        "positive": "Improving the Kinetic Couplings in Lattice Non-Relativistic QCD: We improve the non-relativistic QCD (NRQCD) action by comparing the\ndispersion relation to that of the continuum through $\\mathcal{O}(p^6)$ in\nperturbation theory. The one-loop matching coefficients of the\n$\\mathcal{O}(p^4)$ kinetic operators are determined, as well as the scale at\nwhich to evaluate $\\alpha_s$ in the $V$-scheme for each quantity. We utilise\nautomated lattice perturbation theory using twisted boundary conditions as an\ninfrared regulator. The one-loop radiative corrections to the mass\nrenormalisation, zero-point energy and overall energy-shift of an NRQCD\n$b$-quark are also found. We also explore how a Fat$3$-smeared NRQCD action and\nchanges of the stability parameter $n$ affect the coefficients. Finally, we use\ngluon field ensembles at multiple lattice spacing values, all of which include\n$u$, $d$, $s$ and $c$ quark vacuum polarisation, to test how the improvements\naffect the non-perturbatively determined $\\Upsilon(1S)$ and $\\eta_b(1S)$\nkinetic masses, and the tuning of the $b$ quark mass."
    },
    {
        "anchor": "Orbitally excited and hybrid mesons from the lattice: We discuss in general the construction of gauge-invariant non-local meson\noperators on the lattice. We use such operators to study the $P$- and $D$-wave\nmesons as well as hybrid mesons in quenched QCD, with quark masses near the\nstrange quark mass. The resulting spectra are compared with experiment for the\norbital excitations. For the states produced by gluonic excitations (hybrid\nmesons) we find evidence of mixing for non-exotic quantum numbers. We give\npredictions for masses of the spin-exotic hybrid mesons with $J^{PC}=1^{-+},\\\n0^{+-}$, and $2^{+-}$.",
        "positive": "Updates on Nucleon Form Factors from Clover-on-HISQ Lattice Formulation: Updates on results for the electric, magnetic and axial vector form factors\nare presented. The data analyzed cover high statistics measurements on 11\nensembles generated with 2+1+1 flavors of HISQ fermions by the MILC\ncollaboration. The data cover the range $0.057\\;\\mathrm{fm} < a <\n0.15\\;\\mathrm{fm}$ in lattice spacing, $135\\;\\mathrm{MeV} < M_\\pi <\n320\\;\\mathrm{MeV}$ in the pion mass and $3.3 < M_\\pi L < 5.5 $ in the lattice\nsize. Fits to control excited-state contamination use up to 3-states in the\nspectral decomposition of the 3-point functions. The simultaneous\nchiral-continuum-finite-volume fits include leading order corrections in each\nof the three variables."
    },
    {
        "anchor": "Form factor and width of a quantum string: In the Yang-Mills theory, the apparent thickness of the confining string is\nknown to grow logarithmically when its length increases. The same logarithmic\nbroadening also happens to strings in other quantum field theories and domain\nwalls in statistical physics models. Even in quantum field theories, the\ncorrelators used to measure and characterise this phenomenon are analogous to\nthose in statistical physics. In this paper we describe it using the string\nform factor which is a meaningful quantum observable, obtainable in principle\nfrom scattering experiments. We show how the form factor can be obtained from\nfield correlation functions calculated in lattice Monte Carlo simulations. We\napply this method to 2+1-dimensional scalar theory in the strong coupling\nlimit, where it is equivalent to the 3D Ising model, and through duality also\nto 2+1-dimensional $\\mathbb{Z}_2$ gauge theory. We measure the string form\nfactor by simulating the Ising model, and demonstrate that it displays the same\nlogarithmic broadening as observed by other quantities.",
        "positive": "Charmonium-like states from scattering on the lattice: Three charmonium-like states were studied using lattice QCD. The candidate\nfor X(3872) was found slightly below DD* threshold in the channel with\nJ^PC=1^++ and I=0, where cc as well as DD* and $J/\\psi \\omega$ interpolating\noperators were used. A charmonium-like channel with J^PC=1^+- and I=1 was also\nstudied, as the recently discovered Z_c^+(3900) might reside there. Here\n$J/\\psi \\pi$ and DD* scattering states were found, but no candidate for the\nZ_c^+(3900). We present also preliminary results for the J^PC=0^++ charmonium\nchannel, where cc, DD and $J/\\psi \\omega$ interpolating operators were used. A\ncandidate for a resonance, chi_c0^', that couples to DD in J^PC=0^++ was found."
    },
    {
        "anchor": "Conformality at large number of fermion flavors and composite Higgs: The many open questions concerning the existence of IR and UV fixed points in\ngauge theories as a function of the number of fermion flavors and bare coupling\nare briefly reviewed and discussed. It is pointed out that only a small subset\nof potential IR-conformal gauge theories, i.e. theories whose IR behavior is\ndetermined by an IR fixed point, has so far been examined. It is suggested that\nthe naturally light scalar composites that seem to appear generically as lowest\nstates in the non-QCD-like spectrum of such theories provide a natural basis\nfor composite Higgs models, where the composite Higgs is not a NG boson and\nsome of the usual fine-tuning problems are evaded.",
        "positive": "On the existence of a first order phase transition at small vacuum angle\n  $\u03b8$ in the $CP^3$ model: We examine the phase structure of the $CP^3$ model as a function of $\\theta$\nin the weak coupling regime. It is shown that the model has a first order phase\ntransition at small $\\theta$. We pay special attention to the extrapolation of\nthe data to the infinite volume. It is found that the critical value of\n$\\theta$ decreases towards zero as $\\beta$ is taken to infinity."
    },
    {
        "anchor": "Quenched $B_K$-parameter with the Wilson and Clover actions at $\u03b2=\n  6.0$: We present results for the Kaon $B$ parameter from a sample of $200$\nconfigurations using the Wilson action and $460$ configurations using the\nClover action, on a $18^3 \\times 64$ lattice at $\\beta=6.0$. A slight\nimprovement of the chiral behaviour of $B_K$ is observed due to the Clover\naction. We have also compared the results for $B_K$ obtained from two different\nprocedures for the boosting of the coupling constant $g$. We observe a strong\ndependence of $B_K$ on the prescription adopted for $g$ in the Wilson case,\ncontrary to the results of the Clover case which are almost unaffected by the\nchoice of $g$. Combining some recently obtained non perturbative estimates for\nthe renormalisation constants with our Clover matrix element, we observe a\nsignificant improvement in the chiral behaviour of $B_K$.",
        "positive": "Euclidean gravity attracts: We look at gravitational attraction in simplicial gravity using the dynamical\ntriangulation method. On the dynamical triangulation configurations we measure\nquenched propagators of a free massive scalar field. The masses measured from\nthese propagators show that gravitational attraction is present."
    },
    {
        "anchor": "Quantum Simulation of Field Theories Without State Preparation: We propose an algorithm for computing real-time observables using a quantum\nprocessor while avoiding the need to prepare the full quantum state. This\nreduction in quantum resources is achieved by classically sampling\nconfigurations in imaginary-time using standard lattice field theory. These\nconfigurations can then be passed to quantum processor for time-evolution. This\nmethod encounters a signal-to-noise problem which we characterize, and we\ndemonstrate the application of standard lattice QCD methods to mitigate it.",
        "positive": "An Algorithm for Dynamic Load Balancing of Synchronous Monte Carlo\n  Simulations on Multiprocessor Systems: We describe an algorithm for dynamic load balancing of geometrically\nparallelized synchronous Monte Carlo simulations of physical models. This\nalgorithm is designed for a (heterogeneous) multiprocessor system of the MIMD\ntype with distributed memory. The algorithm is based on a dynamic partitioning\nof the domain of the algorithm, taking into account the actual processor\nresources of the various processors of the multiprocessor system."
    },
    {
        "anchor": "Topological susceptibility from twisted mass fermions using spectral\n  projectors: We discuss the computation of the topological susceptibility using the method\nof spectral projectors and dynamical twisted mass fermions. We present our\nanalysis concerning the O(a)-improvement of the topological susceptibility and\nwe show numerical results for Nf=2 and Nf=2+1+1 flavours, performing a study of\nthe quark mass dependence in terms of leading order chiral perturbation theory.",
        "positive": "A possible scaling region of chiral fermions on a lattice: We present the details of analyzing an $SU_L(2)\\otimes U_R(1)$ chiral theory\nwith multifermion couplings on a lattice. An existence of a possible scaling\nregion in the phase space of multifermion couplings for defining the continuum\nlimit of chiral fermions is advocated. In this scaling region, no spontaneous\nsymmetry breaking occurs; the ``spectator'' fermion $\\psi_R(x)$ is a free mode\nand decoupled; doublers are decoupled as massive Dirac fermions consistently\nwith the $SU_L(2)\\otimes U_R(1)$ chiral symmetry, whereas the normal mode of\n$\\psi_L^i(x)$ is plausibly speculated to be chiral in the continuum limit. This\nis not in agreement with the general belief of the definite failure of theories\nso constructed."
    },
    {
        "anchor": "Some approximate analytical methods in the study of the self-avoiding\n  loop model with variable bending rigidity and the critical behaviour of the\n  strong coupling lattice Schwinger model with Wilson fermions: Some time ago Salmhofer demonstrated the equivalence of the strong coupling\nlattice Schwinger model with Wilson fermions to a certain 8-vertex model which\ncan be understood as a self-avoiding loop model on the square lattice with\nbending rigidity $\\eta = 1/2$ and monomer weight $z = (2\\kappa)^{-2}$. The\npresent paper applies two approximate analytical methods to the investigation\nof critical properties of the self-avoiding loop model with variable bending\nrigidity, discusses their validity and makes comparison with known MC results.\nOne method is based on the independent loop approximation used in the\nliterature for studying phase transitions in polymers, liquid helium and cosmic\nstrings. The second method relies on the known exact solution of the\nself-avoiding loop model with bending rigidity $\\eta = 1/\\sqrt{2}$. The present\ninvestigation confirms recent findings that the strong coupling lattice\nSchwinger model becomes critical for $\\kappa_{cr} \\simeq 0.38-0.39$. The phase\ntransition is of second order and lies in the Ising model universality class.\nFinally, the central charge of the strong coupling Schwinger model at\ncriticality is discussed and predicted to be $c = 1/2$.",
        "positive": "Canonical simulations with worldlines: an exploratory study in\n  $\u03c6^{4}_{2}$ lattice field theory: In this letter we explore the perspectives for canonical simulations in the\nworldline formulation of a lattice field theory. Using the charged $\\phi^4$\nfield in two dimensions as an example we present the details of the canonical\nformulation based on worldlines and outline algorithmic strategies for\ncanonical worldline simulations. We discuss the steps for converting the data\nfrom the canonical approach to the grand canonical picture which we use for\ncross-checking our results. The canonical approach presented here can easily be\ngeneralized to other lattice field theories with a worldline representation."
    },
    {
        "anchor": "Non-perturbatively Determined Relativistic Heavy Quark Action: We present a method to non-perturbatively determine the parameters of the\non-shell, $O(a)$-improved relativistic heavy quark action. These three\nparameters, $m_0$, $\\zeta$, and $c_B=c_E$ are obtained by matching\nfinite-volume, heavy-heavy and heavy-light meson masses to the exact\nrelativistic spectrum through a finite-volume, step-scaling recursion\nprocedure. We demonstrate that accuracy on the level of a few percent can be\nachieved by carrying out this matching on a pair of lattices with equal\nphysical spatial volumes but quite different lattice spacings. A fine lattice\nwith inverse lattice spacing $1/a=5.4$ GeV and $24^3 \\times 48$ sites and a\ncoarse, $1/a=3.6$ GeV, $16^3 \\times 32$ lattice are used together with a heavy\nquark mass $m$ approximately that of the charm quark. This approach is unable\nto determine the initially expected, four heavy-quark parameters: $m_0$,\n$\\zeta$, $c_B$ and $c_E$. This apparent non-uniqueness of these four parameters\nmotivated the analytic result, presented in a companion paper, that this set is\nredundant and that the restriction $c_E=c_B$ is permitted through order $a|\\vec\np|$ and to all orders in $m a$ where $\\vec p$ is the heavy quark's spatial\nmomenta.",
        "positive": "Lattice Matter: I review recent developments in the study of strongly interacting field\ntheories with non-zero chemical potential mu. In particular I focus on (a) the\ndetermination of the QCD critical endpoint in the (mu,T) plane; (b) superfluid\ncondensates in Two Color QCD; and (c) Fermi surface effects in the NJL model.\nSome remarks are made concerning the relation of superconductivity with the\nsign problem."
    },
    {
        "anchor": "Equation of State and the Finite Temperature Transition in QCD: This talk provides a summary of the results obtained by the HotQCD\ncollaboration on the equation of state and the crossover transition in 2+1\nflavor QCD. We investigate bulk thermodynamic quantities - energy density,\npressure, entropy density, and the speed of sound over the temperature range\n140 < T < 540 MeV. These results have been obtained on lattices of temporal\nsize N_tau = 6 and 8 and with two improved staggered fermion actions, asqtad\nand p4. Our most extensive results are with masses of the two degenerate light\nquarks set at m_l = 0.1 m_s corresponding to the Goldstone pion mass m_pi\nbetween 220-260 MeV. In these simulations, the strange quark mass is tuned to\nits physical value and constant values of m_l/m_s define lines of constant\nphysics. We also summarize the current state of results on observables\nsensitive to the chiral and deconfining physics -- the light and strange quark\nnumber susceptibilities, the chiral condensate and its susceptibility, and the\nrenormalized Polyakov loop. Our results indicate that the deconfinement and\nchiral symmetry restoration occur in the same narrow temperature interval.",
        "positive": "HAL QCD method and Nucleon-Omega interaction with physical quark masses: In lattice QCD, both direct method and HAL QCD method are used to investigate\nthe two-baryon systems. We show that due to the contamination of the scattering\nexcited states, it is challenging to measure the eigenenergy from the temporal\ncorrelation in the direct method, while the HAL QCD method can extract the\ninformation of the interaction from both scattering states and ground state by\nusing the spatial correlation. We examine the systematic uncertainty of the\nderivative expansion in the HAL QCD method, which is found to be well under\ncontrol at the low energies. By using the time-dependent HAL QCD method, we\nstudy the nucleon($N$)-Omega($\\Omega$) system in the $^5$S$_2$ channel with\nalmost physical quark masses at $m_\\pi \\simeq 146$ MeV. We find the interaction\nis attractive at all distances, which produces a quasi-bound state with the\nbinding energy 1.54(0.30)($^{+0.04}_{-0.10}$) MeV. We also consider the extra\nCoulomb interaction in the $p\\Omega^{-}$($^5$S$_2$) system, whose binding\nenergy becomes 2.46(0.34)($^{+0.04}_{-0.01}$) MeV. $N\\Omega$($^5$S$_2$)\ndibaryon could be searched through two-particle correlations in the heavy ion\ncollision experiments."
    },
    {
        "anchor": "Relativistic heavy quarks on the lattice: We investigate feasibility of relativistic approaches to the heavy quark\nphysics on both anisotropic and isotropic lattices. Our peturbative calculation\nreveals that the anisotropic lattice is not theoretically adovantageous over\nthe isotropic one to control $m_Q a$ errors. We instead propose a new\nrelativistic approach to handle heavy quarks on the isotropic lattice.",
        "positive": "Spatial string tension in gluodynamics at finite temperature in a\n  spherical model approximation: Spatial string tension is computed in finite temperature gluodynamics on\nasymmetric lattices in a spherical model approximation. Conditions of scaling\nbehavior are specified. Discrepancies with a standard renormalisation procedure\nare discussed."
    },
    {
        "anchor": "The Gluon Propagator at High Temperature: We study the gluon propagator in Landau gauge in the deconfined phase of\n$SU(2)$ gauge theory. From the long-distance behaviour of correlation functions\nof temporal and spatial components of the gauge fields we extract electric\n($m_e$) and magnetic ($m_m$) screening masses. For temperatures larger than\ntwice $T_c$ we find no additional temperature dependence in $m_e(T)/T$, while\n$m_m(T)/T$ drops with increasing temperature. The decrease is consistent with\nthe expected behaviour, $m_m(T) \\sim g^2(T)T$. We find $m_e(T) = 2.484(52)T$\nand $m_m(T) = 0.466(15) g^2(T) T$.",
        "positive": "Evaluation of disconnected quark loops for hadron structure using GPUs: A number of stochastic methods developed for the calculation of fermion loops\nare investigated and compared, in particular with respect to their efficiency\nwhen implemented on Graphics Processing Units (GPUs). We assess the performance\nof the various methods by studying the convergence and statistical accuracy\nobtained for observables that require a large number of stochastic noise\nvectors, such as the isoscalar nucleon axial charge. The various methods are\nalso examined for the evaluation of sigma-terms where noise reduction\ntechniques specific to the twisted mass formulation can be utilized thus\nreducing the required number of stochastic noise vectors."
    },
    {
        "anchor": "Photodisintegration of a Bound State on the Torus: In this article the cross-section for the photodisintegration of a bound\nstate is expressed, order by order in the multipole expansion, in terms of\nmatrix elements between states living on the three-dimensional torus. The\nmotivation is to make the process amenable to Monte-Carlo simulations. The case\nof the deuteron is discussed.",
        "positive": "Supersymmetric lattice models in one and two dimensions: We study and simulate N=2 supersymmetric Wess-Zumino models in one and two\ndimensions. For any choice of the lattice derivative, the theories can be made\nmanifestly supersymmetric by adding appropriate improvement terms corresponding\nto discretizations of surface integrals. In particular, we check that fermionic\nand bosonic masses coincide and the unbroken Ward identities are fulfilled to\nhigh accuracy. Equally good results for the effective masses can be obtained in\na model with the SLAC derivative (even without improvement terms). In two\ndimensions we introduce a non-standard Wilson term in such a way that the\ndiscretization errors of the kinetic terms are only of order a squared. Masses\nextracted from the corresponding manifestly supersymmetric model prove to\napproach their continuum values much quicker than those from a model containing\nthe standard Wilson term. Again, a comparable enhancement can be achieved in a\ntheory using the SLAC derivative."
    },
    {
        "anchor": "Anomalous dimensions of four-fermion operators from conformal EWSB\n  dynamics: (Quasi)conformal scaling of composite operators from a strongly coupled EWSB\ndynamics helps to produce the characteristic hierarchies exhibited by the\nflavour couplings of the SM. It is however crucial to ensure that specific\nmodels satisfy bounds on Higgs and flavour dynamics; this in turn requires to\ncontrol not only the anomalous dimensions of bilinears, but also those of\nhigher-dimensional operators. We report on an ongoing effort to determine\nfour-fermion operator anomalous dimensions, via Schr\\\"odinger Functional\ntechniques, in the benchmark scenario of Minimal Walking Technicolour.",
        "positive": "The Simple Center Projection of SU(2) Gauge Theory: We consider the SU(2) lattice gauge model. We propose a new gauge invariant\ndefinition of center projection, which we call the Simple Center Projection. We\ndemonstrate the center dominance, i.e., the coincidence of the projected\npotential with the full potential up to the mass renormalization term at low\nenergies. We also consider the center vortices and the center monopoles ({\\em\nnexuses}). It turns out that the behavior of such objects qualitatively\ncoincides with the behavior of the vortices and monopoles in the Maximal Center\ngauge. The connection of the condensation of nexuses with the dual\nsuperconductor theory is discussed. Numerically the procedure of extracting the\ncenter vortices proposed in this paper is much simpler than the usual Maximal\nCenter Projection."
    },
    {
        "anchor": "Continuous Time Monte Carlo for Lattice QCD in the Strong Coupling Limit: We present results for lattice QCD with staggered fermions in the limit of\ninfinite gauge coupling, obtained from a worm-type Monte Carlo algorithm on a\ndiscrete spatial lattice but with continuous Euclidean time. This is achieved\nby sending both the anisotropy parameter $\\gamma^2\\simeq a/\\at$ and the number\nof time-slices $N_\\tau$ to infinity, keeping the ratio $\\gamma^2/N_\\tau \\simeq\naT$ fixed. In this limit, ambiguities arising from the anisotropy parameter\n$\\gamma$ are eliminated and discretization errors usually introduced by a\nfinite temporal lattice extent $\\Nt$ are absent. The obvious gain is that no\ncontinuum extrapolation $N_\\tau \\rightarrow \\infty$ has to be carried out.\nMoreover, the algorithm is faster and the sign problem disappears completely.\n  As a first application, we determine the phase diagram as a function of\ntemperature and real and imaginary baryon chemical potential. We compare our\ncomputations with those on lattices with discrete Euclidean time.\nDiscretization errors due to finite $\\Nt$ in previous studies turn out to be\nlarge at low temperatures.",
        "positive": "Lattice QCD with Ginsparg-Wilson fermions: Lattice QCD using fermions whose Dirac operator obeys the Ginsparg-Wilson\nrelation, is perhaps the best known formulation of QCD with a finite cutoff. It\nreproduces all the low energy QCD phenomenology associated with chiral symmetry\nat finite lattice spacings. In particular it explains the origin of massless\npions due to spontaneous chiral symmetry breaking and leads to new ways to\napproach the U(1) problem on the lattice. Here we show these results in the\npath integral formulation and derive for the first time in lattice QCD a known\nformal continuum relation between the chiral condensate and the topological\nsusceptibility. This relation leads to predictions for the critical behavior of\nthe topological susceptibility near the phase transition and can now be checked\nin Monte-Carlo simulations even at finite lattice spacings."
    },
    {
        "anchor": "Problems in Lattice Gauge Fixing: We review many topics and results about numeric gauge fixing in lattice QCD.",
        "positive": "Quarks and gluons in dense two-colour QCD: We compute quark and gluon propagators in 2-colour QCD at large baryon\nchemical potential mu. The gluon propagator is found to be antiscreened at\nintermediate mu and screened at large mu. The quark propagator is drastically\nmodified in the superfluid region as a result of the formation of a superfluid\ngap."
    },
    {
        "anchor": "Practical methods for a direct calculation of $\u0394I=1/2$ $K$ to\n  $\u03c0\u03c0$ Decay: A direct calculation of the complex $\\Delta I=1/2$ kaon decay amplitude is\nnotoriously difficult because of the presence of disconnected graphs. Here we\ndescribe and demonstrate two practical methods to defeat this problem: the\nEigCG algorithm and the use of time-separated $\\pi-\\pi$ sources. With a fine\ntuned EigCG implementation for domain wall fermions, the calculation of light\nquark propagators is accelerated by a factor of 5-10 on a variety of lattices\nfrom small ($16^3\\times32\\times16$) to large ($32^3\\times64\\times32$). In\naddition, a substantial reduction in noise is achieved by separating each of\nthe sources for the two pions in the time direction by 2-5 lattice spacings.\nThese methods are combined in a calculation of $K$ to $\\pi\\pi$ threshold decay\nusing a $24^3\\times64\\times16$ volume and 329 MeV pions. These methods result\nin non-zero signals for both Re($A_0$) and Im($A_0$) from 138 gauge\nconfigurations.",
        "positive": "Applications of lattice QCD techniques for condensed matter systems: We review the application of lattice QCD techniques, most notably the Hybrid\nMonte-Carlo (HMC) simulations, to first-principle study of tight-binding models\nof crystalline solids with strong inter-electron interactions. After providing\na basic introduction into the HMC algorithm as applied to condensed matter\nsystems, we review HMC simulations of graphene, which in the recent years have\nhelped to understand the semi-metal behavior of clean suspended graphene at the\nquantitative level. We also briefly summarize other novel physical results\nobtained in these simulations. Then we comment on the applicability of Hybrid\nMonte-Carlo to topological insulators and Dirac and Weyl semi-metals and\nhighlight some of the relevant open physical problems. Finally, we also touch\nupon the lattice strong-coupling expansion technique as applied to condensed\nmatter systems."
    },
    {
        "anchor": "Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum\n  Entropy Method: We study the mass spectra of excited baryons with the use of the lattice QCD\nsimulations. We focus our attention on the problem of the level ordering\nbetween the positive-parity excited state N'(1440) (the Roper resonance) and\nthe negative-parity excited state N^*(1535). Nearly perfect parity projection\nis accomplished by combining the quark propagators with periodic and\nanti-periodic boundary conditions in the temporal direction. Then we extract\nthe spectral functions from the lattice data by utilizing the maximum entropy\nmethod. We observe that the masses of the N' and N^* states are close for wide\nrange of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the\nphenomenological prediction of the quark models. The role of the Wilson\ndoublers in the baryonic spectral functions is also studied.",
        "positive": "Emergence of a new $SU(4)$ symmetry in the baryon spectrum: Recently a large degeneracy of $J=1$ mesons, that is larger than the $SU(2)_L\n\\times SU(2)_R \\times U(1)_A$ symmetry of the QCD Lagrangian, has been\ndiscovered upon truncation of the near-zero modes from the valence quark\npropagators. It has been found that this degeneracy represents the $SU(4)$\ngroup that includes the chiral rotations as well as the mixing of left- and\nright-handed quarks. This symmetry group turns out to be a symmetry of\nconfinement in QCD. Consequently, one expects that the same symmetry should\npersist upon the near-zero mode removal in other hadron sectors as well. It has\nbeen shown that indeed the $J=2$ mesons follow the same symmetry pattern upon\nthe low-lying mode elimination. Here we demonstrate the $SU(4)$ symmetry of\nbaryons once the near-zero modes are removed from the quark propagators. We\nalso show a degeneracy of states belonging to different irreducible\nrepresentations of $SU(4)$. This implies a larger symmetry, that includes\n$SU(4)$ as a subgroup."
    },
    {
        "anchor": "Lattice Regularization of the Chiral Schwinger Model: We analyze the chiral Schwinger model on an infinite lattice using the\ncontinuum definition of the fermion determinant and a linear interpolation of\nthe lattice gauge fields. For non-compact and Wilson formulation of the gauge\nfield action it is proven that the effective lattice model is\nOsterwalder-Schrader positive, which is a sufficient condition for the\nreconstruction of a physical Hilbert space from the model defined on a\nEuclidean lattice. For the non-compact model we furthermore establish the\nexistence of critical points where the corresponding continuum theory can be\nreconstructed. We show that the continuum limit for the two-point functions of\nfield strength and chiral densities can be controlled analytically. The article\nends with some remarks on fermionic observables.",
        "positive": "Renormalization Constants using Quark States in Fixed Gauge: We present a status report on our calculation of the renormalization\nconstants for the quark bilinears in quenched (O(a)) improved Wilson theory at\n(beta=6.4) using quark states in Landau gauge."
    },
    {
        "anchor": "Finite-temperature chiral condensate and low-lying Dirac eigenvalues in\n  quenched SU(2) lattice gauge theory: The spectrum of low-lying eigenvalues of overlap Dirac operator in quenched\nSU(2) lattice gauge theory with tadpole-improved Symanzik action is studied at\nfinite temperatures in the vicinity of the confinement-deconfinement phase\ntransition defined by the expectation value of the Polyakov line. The value of\nthe chiral condensate obtained from the Banks-Casher relation is found to drop\ndown rapidly at T = Tc, though not going to zero. At Tc' = 1.5 Tc = 480 MeV the\nchiral condensate decreases rapidly one again and becomes either very small or\nzero. At T < Tc the distributions of small eigenvalues are universal and are\nwell described by chiral orthogonal ensemble of random matrices. In the\ntemperature range above Tc where both the chiral condensate and the expectation\nvalue of the Polyakov line are nonzero the distributions of small eigenvalues\nare not universal. Here the eigenvalue spectrum is better described by a\nphenomenological model of dilute instanton - anti-instanton gas.",
        "positive": "Remarks on the hadronic matrix elements relevant to the SUSY K-Kbar\n  mixing amplitude: We compute the 1-loop chiral corrections to the bag parameters which are\nneeded for the discussion of the SUSY K-Kbar mixing problem in both finite and\ninfinite volume. We then show how the bag parameters can be combined among\nthemselves and with some auxiliary quantities and thus sensibly reduce the\nsystematic errors due to chiral extrapolations as well as those due to finite\nvolume artefacts present in the results obtained from lattice QCD. We also show\nthat in some cases these advantages remain as such even after including the\n2-loop chiral corrections. Similar discussion is also made for the K --> pi\nelectro-weak penguin operators."
    },
    {
        "anchor": "Low energy spectra in many flavor QCD with Nf=12 and 16: We present our result of the many-flavor QCD. Information of the phase\nstructure of many-flavor SU(3) gauge theory is of great interest, since the\ngauge theories with the walking behavior near the infrared fixed point are\ncandidates of new physics for the origin of the dynamical electroweak symmetry\nbreaking. We study the SU(3) gauge theories with 12 and 16 fundamental\nfermions. Utilizing the HISQ type action which is useful to study the continuum\nphysics, we analyze the lattice data of the mass and the decay constant of the\npseudoscalar meson and the mass of the vector meson as well at several values\nof lattice spacing and fermion mass. The finite size scaling test in the\nconformal hypothesis is also performed. Our data is consistent with the\nconformal scenario for Nf=12. We obtain the mass anomalous dimension $\\gamma_m\n\\sim 0.4-0.5$. An update of $N_f=16$ study is also shown.",
        "positive": "Progress on Excited Hadrons in Lattice QCD: The study of excited hadron spectra using Lattice QCD is currently evolving.\nAn important step toward obtaining resonance parameters from Lattice QCD is the\ncalculation of finite volume energy spectra. Somewhat more rigorous studies of\nfinite volume spectra are currently possible and should be completed in the\nnear future. The inclusion of disconnected diagrams is increasingly commonplace\nand the simplest systems which involve mixing between single- and multi-hadron\ninterpolating fields are being studied. Advances in all-to-all algorithms which\nhave been crucial in this progress are reviewed and a survey of current results\nis given. Nevertheless, such results are preliminary and a thorough discussion\nof systematic errors is required. We discuss several such sources of error,\nfocusing on excited state contamination and the use of the generalized\neigenvalue problem. Also, the calculation of matrix elements between finite\nvolume Hamiltonian eigenstates is discussed."
    },
    {
        "anchor": "Decays of Heavy Mesons: We present preliminary results for heavy to light transitions of pseudoscalar\nmesons, induced by the vector and tensor operators. This lattice study is\nperformed in quenched approximation, by using the nonperturbatively improved\nWilson action and operators. We also update the values of the heavy-light meson\ndecay constants.",
        "positive": "The Infrared Landau Gauge Gluon Propagator from Lattice QCD: The quenched Landau gauge gluon propagator is investigated in lattice QCD\nwith large assimetric lattices, accessing momenta as low as $q \\sim 100$ MeV or\nsmaller. Our investigation focus on the IR limit of the gluon dressing\nfunction, testing the compatibility with recent solutions of the\nDyson-Schwinger equations. In particular, the low energy parameters $\\kappa$\nand $\\alpha (0)$ are measured."
    },
    {
        "anchor": "The pion form factor on the lattice at zero and finite temperature: We calculate the electromagnetic form factor of the pion in quenched lattice\nQCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is\nused together with the consistently O(a) improved current. We calculate the\npion form factor for masses down to m_pi = 360 MeV, extract the charge radius,\nand extrapolate toward the physical pion mass. In the second part, we discuss\nresults for the pion form factor and charge radius at 0.93 T_c and compare with\nzero temperature results.",
        "positive": "A formulation of domain wall fermions in the Schroedinger functional: We present a formulation of domain wall fermions in the Schroedinger\nfunctional by following the universality argument given by L\\\"uscher. To check\nwhether the formulation works, we examine the lowest eigenmode of the free\ndomain wall fermion operator. We confirm that the theory belongs to a correct\nuniversality class and that the eigenvector is localized near the boundaries of\nthe fifth dimension. We also investigate the chiral symmetry breaking structure\nof the four dimentional effective operator. We observe that the bulk chiral\nsymmetry breaking disappears for a large fifth dimensional size, while the\nbreaking originated by the boundary effects persists and exponetially decays\naway from the time boundaries."
    },
    {
        "anchor": "Finite Volume Study of the Delta Magnetic Moments Using Dynamical Clover\n  Fermions: We calculate the magnetic dipole moment of the Delta baryon using a\nbackground magnetic field on 2+1-flavors of clover fermions on anisotropic\nlattices. We focus on the finite volume effects that can be significant in\nbackground field studies, and thus we use two different spatial volumes in\naddition to several quark masses.",
        "positive": "Linking confinement to spectral properties of the Dirac operator: We represent Polyakov loops and their correlators as spectral sums of\neigenvalues and eigenmodes of the lattice Dirac operator. The deconfinement\ntransition of pure gauge theory is characterized as a change in the response of\nmoments of eigenvalues to varying the boundary conditions of the Dirac\noperator. We argue that the potential between static quarks is linked to\nspatial correlations of Dirac eigenvectors."
    },
    {
        "anchor": "Status on Lattice Calculations of the Proton Spin Decomposition: Lattice calculations of the proton spin components is reviewed. The lattice\nresults of the quark spin from the axial-vector current matrix element at $\\sim\n0.3- 0.4$ is smaller than those from the constituent quark models. This is\nlargely due to the fact that the vacuum polarization contribution from the\ndisconnected insertion is negative. Its connection with the anomalous Ward\nidentity is clarified and verified numerically. This resolves the contentious\nissue in the `proton spin crisis'. The glue spin and angular momentum are found\nto be large and there is notable contribution from the quark orbital angular\nmomentum. Renormalization, mixing and normalization of the quark and glue\nangular momenta are discussed. With sufficient precision, they can be compared\nwith more precise experimental measurements when the electron-ion collider\nfacility is available.",
        "positive": "On the mass of the world-sheet `axion' in SU(N) gauge theories in 3+1\n  dimensions: There is numerical evidence that the world sheet action of the confining flux\ntube in D=3+1 SU(N) gauge theories contains a massive excitation with 0-\nquantum numbers whose mass shows some decrease as one goes from SU(3) to SU(5).\nIt has furthermore been shown that this particle is naturally described as\narising from a topological interaction term in the world-sheet action, so that\none can describe it as being `axion'-like. Recently it has been pointed out\nthat if the mass of this `axion' vanishes as N -> oo then it becomes possible\nfor the world sheet theory to be integrable in the planar limit. In this paper\nwe perform lattice calculations of this `axion' mass from SU(2) to SU(12),\nwhich allows us to make a controlled extrapolation to N=oo and so test this\ninteresting possibility. We find that the `axion' does not in fact become\nmassless as N -> oo. So if the theory is to possess planar integrability then\nit must be some other world sheet excitation that becomes massless in the\nplanar limit."
    },
    {
        "anchor": "Geometric Measurement of Topological Susceptibility on Large Lattices: The topological susceptibility of the quenched QCD vacuum is measured on\nlarge lattices for three $\\beta$ values from $6.0$ to $6.4$. Charges possibly\ninduced by $O(a)$ dislocations are identified and shown to have little effect\non the measured susceptibility. As $\\beta$ increases, fewer such questionable\ncharges are found. Scaling is checked by examining the ratios of the\nsusceptibility to previously existing values of the rho mass, string tension,\nF-pi, and lambda-lattice.",
        "positive": "Nucleon Scalar and Tensor Charges from Lattice QCD with Light Wilson\n  Quarks: We present 2+1 flavor Lattice QCD calculations of the nucleon scalar and\ntensor charges. Using the BMW clover-improved Wilson action with pion masses\nbetween 150 and 350 MeV and three source-sink separations between 0.9 and 1.4\nfm, we achieve good control over excited-state contamination and extrapolation\nto the physical pion mass. As a consistency check, we also present results from\ncalculations using unitary domain wall fermions with pion masses between 300\nand 400 MeV, and using domain wall valence quarks and staggered sea quarks with\npion masses between 300 and 600 MeV."
    },
    {
        "anchor": "Matrix elements from moments of correlation functions: Momentum-space derivatives of matrix elements can be related to their\ncoordinate-space moments through the Fourier transform. We derive these\nexpressions as a function of momentum transfer $Q^2$ for asymptotic in/out\nstates consisting of a single hadron. We calculate corrections to the finite\nvolume moments by studying the spatial dependence of the lattice correlation\nfunctions. This method permits the computation of not only the values of matrix\nelements at momenta accessible on the lattice, but also the momentum-space\nderivatives, providing {\\it a priori} information about the $Q^2$ dependence of\nform factors. As a specific application we use the method, at a single lattice\nspacing and with unphysically heavy quarks, to directly obtain the slope of the\nisovector form factor at various $Q^2$, whence the isovector charge radius. The\nmethod has potential application in the calculation of any hadronic matrix\nelement with momentum transfer, including those relevant to hadronic weak\ndecays.",
        "positive": "Nucleon axial charge in 2+1-flavor dynamical DWF lattice QCD: The current status of some nucleon isovector observables, the vector charge,\n\\(g_V\\), axial charge, \\(g_A\\), quark momentum fraction, \\(\\langle x\n\\rangle_{u-d}\\), and quark helicity fraction, \\(\\langle x \\rangle_{\\Delta u -\n\\Delta d}\\), calculated using recent RBC/UKQCD 2+1-flavor dynamical domain-wall\nfermions (DWF) lattice QCD ensembles are reported: with Iwasaki gauge action at\ninverse lattice spacing, \\(a^{-1}\\), of about 1.7 GeV, linear lattice extent,\n\\(L\\), of about 2.7 fm, pion mass, \\(m_\\pi\\), of about 420 and 330 MeV, and\nwith Iwasaki\\(\\times\\)DSDR gauge action at \\(a^{-1}\\) of about 1.4 GeV, \\(L\\)\nof about 4.6 fm, and \\(m_\\pi\\) of about 250 and 170 MeV. The calculations have\nbeen refined with enhanced statistics, in particular through successful\napplication of the all-mode-averaging (AMA) technique for the 170- and 330-MeV\nensembles. As a result, the precision agreement seen in the charge ratio,\n\\(g_A/g_V\\), for 420-MeV and 250-MeV ensembles that share the finite-size\nscaling parameter \\(m_\\pi L\\) of about 5.8 is more significant with new values\nof 1.17(2) and 1.18(4) respectively. We also studied the dependence on the\nsource-sink separation in the lightest ensemble of 170-MeV, by comparing the\ncases with the separation of about 1.0 and 1.3 fm and did not see any\ndependence: contamination from the excited states are well under control in our\nchoice of source and sink smearing. The axial charge, \\(g_A\\) and the ratio,\n\\(g_A/g_V\\), shows a long-range autocorrelation that extends the entire range\nof configurations that were so far analyzed, almost 700 hybrid Molecular\nDynamics time, in the lightest ensemble of \\(m_\\pi=170\\) MeV. The other\nobservables do not show any autocorrelation with the interval of 16\ntrajectories."
    },
    {
        "anchor": "Spectral Functions, Maximum Entropy Method and Unconventional Methods in\n  Lattice Field Theory: We present two unconventional methods of extracting information from hadronic\n2-point functions produced by Monte Carlo simulations. The first is an\nextension of earlier work by Leinweber which combines a QCD Sum Rule approach\nwith lattice data. The second uses the Maximum Entropy Method to invert the\n2-point data to obtain estimates of the spectral function. The first approach\nis applied to QCD data, and the second method is applied to the\nNambu--Jona-Lasinio model in (2+1)D. Both methods promise to augment the\ncurrent approach where physical quantities are extracted by fitting to pure\nexponentials.",
        "positive": "Cutoff effects in maximally twisted LQCD: The Symanzik analysis of correlators in lattice QCD with maximally twisted\nWilson fermions reveals that there exist cutoff artifacts which tend to become\nlarge as the quark mass gets small. We show that these effects can be reduced\nto a negligible level by either introducing the clover term in the action or,\nas already suggested in the literature, by a suitable choice of the critical\nmass. Recent simulation data support these conclusions."
    },
    {
        "anchor": "D-Meson Mixing in 2+1-Flavor Lattice QCD: We present results for neutral D-meson mixing in 2+1-flavor lattice QCD. We\ncompute the matrix elements for all five operators that contribute to D mixing\nat short distances, including those that only arise beyond the Standard Model.\nOur results have an uncertainty similar to those of the ETM collaboration (with\n2 and with 2+1+1 flavors). This work shares many features with a recent\npublication on B mixing and with ongoing work on heavy-light decay constants\nfrom the Fermilab Lattice and MILC Collaborations.",
        "positive": "Isospin splittings in the light baryon octet from lattice QCD and QED: While electromagnetic and up-down quark mass difference effects on octet\nbaryon masses are very small, they have important consequences. The stability\nof the hydrogen atom against beta decay is a prominent example. Here we include\nthese effects by adding them to valence quarks in a lattice QCD calculation\nbased on $N_f=2+1$ simulations with 5 lattice spacings down to 0.054 fm,\nlattice sizes up to 6 fm and average up-down quark masses all the way down to\ntheir physical value. This allows us to gain control over all systematic\nerrors, except for the one associated with neglecting electromagnetism in the\nsea. We compute the octet baryon isomultiplet mass splittings, as well as the\nindividual contributions from electromagnetism and the up-down quark mass\ndifference. Our results for the total splittings are in good agreement with\nexperiment."
    },
    {
        "anchor": "On the top of the energy barrier. Margarita Garcia Perez: We present results related to the search of SU(2) instantons on a geometry\n$[0,L]^3\\times [0,T]$ obtained using over-improved cooling with fixed boundary\nconditions. We also introduce a criterion for finding a sphaleron at the top of\nthe energy barrier of the instanton path.",
        "positive": "Z_2-Regge versus Standard Regge Calculus in two dimensions: We consider two versions of quantum Regge calculus. The Standard Regge\nCalculus where the quadratic link lengths of the simplicial manifold vary\ncontinuously and the Z_2-Regge Model where they are restricted to two possible\nvalues. The goal is to determine whether the computationally more easily\naccessible Z_2 model still retains the universal characteristics of standard\nRegge theory in two dimensions. In order to compare observables such as average\ncurvature or Liouville field susceptibility, we use in both models the same\nfunctional integration measure, which is chosen to render the Z_2-Regge Model\nparticularly simple. Expectation values are computed numerically and agree\nqualitatively for positive bare couplings. The phase transition within the\nZ_2-Regge Model is analyzed by mean-field theory."
    },
    {
        "anchor": "Lattice QCD determination of states with spin 5/2 or higher in the\n  spectrum of nucleons: Energies for excited isospin 1/2 states that include the nucleon are computed\nusing quenched, anisotropic lattices. Baryon interpolating field operators that\nare used include nonlocal operators that provide $G_2$ irreducible\nrepresentations of the octahedral group. The decomposition of spin 5/2 or\nhigher states is realized for the first time in a lattice QCD calculation. We\nobserve patterns of degenerate energies in the irreducible representations of\nthe octahedral group that correspond to the subduction of the continuum spin\n5/2 or higher.",
        "positive": "Gauge transformations in non-perturbative chiral gauge theories: We reconsider gauge-transformation properties in chiral gauge theories on the\nlattice observing all pertinent information and show that these properties are\nactually determined in a general way for any gauge group and for any value of\nthe index. In our investigations we also clarify several related issues."
    },
    {
        "anchor": "The Calculation of Force in Lattice Quantum Chromodynamics: The calculation of force is most difficult part in lattice Quantum\nChromodynamics (QCD). This lecture gives the details of the force calculation\nin one-loop Symanzik improved action, Wilson fermion with clover term, asqtad\nfermion, HISQ fermion, rooted staggered fermion, smeared fermion, staggered\nWilson fermion, overlap fermion and domain wall fermion. The even-odd\nprecondition are also considered in these calculations.",
        "positive": "Direct numerical computation of disorder parameters: In the framework of various statistical models as well as of mechanisms for\ncolor confinement, disorder parameters can be developed which are generally\nexpressed as ratios of partition functions and whose numerical determination is\nusually challenging. We develop an efficient method for their computation and\napply it to the study of dual superconductivity in 4d compact U(1) gauge\ntheory."
    },
    {
        "anchor": "Effective Polyakov-loop theory for pure Yang-Mills from strong coupling\n  expansion: Lattice Yang-Mills theories at finite temperature can be mapped onto\neffective 3d spin systems, thus facilitating their numerical investigation.\nUsing strong-coupling expansions we derive effective actions for Polyakov loops\nin the $SU(2)$ and $SU(3)$ cases and investigate the effect of higher order\ncorrections. Once a formulation is obtained which allows for Monte Carlo\nanalysis, the nature of the phase transition in both classes of models is\ninvestigated numerically, and the results are then used to predict -- with an\naccuracy within a few percent -- the deconfinement point in the original 4d\nYang-Mills pure gauge theories, for a series of values of $N_\\tau$ at once.",
        "positive": "A Numerical Study of Partially Twisted Boundary Conditions: We investigate the use of partially twisted boundary conditions in a lattice\nsimulation with two degenerate flavours of improved Wilson sea quarks. The use\nof twisted boundary conditions on a cubic volume (L^3) gives access to\ncomponents of hadronic momenta other than integer multiples of 2*pi/L. Partial\ntwisting avoids the need for new gluon configurations for every choice of\nmomentum, while, as recently demonstrated, keeping the finite-volume errors\nexponentially small for the physical quantities investigated in this letter. In\nthis study we focus on the spectrum of pseudo scalar and vector mesons, on\ntheir leptonic decay constants and on Z_P, the matrix element of the pseudo\nscalar density between the pseudo scalar meson and the vacuum. The results\nconfirm the momentum shift imposed by these boundary conditions and in addition\ndemonstrate that they do not introduce any appreciable noise. We therefore\nadvocate the use of partially twisted boundary conditions in applications where\ngood momentum resolution is necessary."
    },
    {
        "anchor": "Worldvolume tempered Lefschetz thimble method and its error estimation: The worldvolume tempered Lefschetz thimble method (WV-TLTM) is an algorithm\ntowards solving the sign problem, where hybrid Monte Carlo updates are\nperformed on a continuous accumulation of flowed surfaces foliated by the\nanti-holomorphic gradient flow (the worldvolume of integration surface).\nSharing the advantage with the original tempered Lefschetz thimble method\n(TLTM) that the sign problem is resolved without introducing the ergodicity\nproblem, the new algorithm is expected to significantly reduce the\ncomputational cost, because it eliminates the need to compute the Jacobian of\nthe flow in generating a configuration. We demonstrate the effectiveness of the\nWV-TLTM with its successful application to the Stephanov model (a chiral random\nmatrix model), for which the complex Langevin method is known to suffer from a\nserious wrong convergence problem. We also discuss the statistical analysis\nmethod for the WV-TLTM.",
        "positive": "Nucleons in Two-Flavor Partially-Quenched Chiral Perturbation Theory: Properties of the proton and the neutron are explored in partially-quenched\nchiral perturbation theory with two non-degenerate light flavors. Masses,\nmagnetic moments, matrix elements of isovector twist-2 operators and\naxial-vector currents are computed at the one-loop level in the chiral\nexpansion."
    },
    {
        "anchor": "Zero temperature string breaking in lattice quantum chromodynamics: The separation of a heavy quark and antiquark pair leads to the formation of\na tube of flux, or \"string\", which should break in the presence of light\nquark-antiquark pairs. This expected zero-temperature phenomenon has proven\nelusive in simulations of lattice QCD. We study mixing between the string state\nand the two-meson decay channel in QCD with two flavors of dynamical sea\nquarks. We confirm that mixing is weak and find that it decreases at level\ncrossing. While our study does not show direct effects of internal quark loops,\nour results, combined with unitarity, give clear confirmation of string\nbreaking.",
        "positive": "Non-uniform measure in 4d simplicial quantum gravity: Four-dimensional euclidean quantum gravity has been studied as a discrete\nmodel based on dynamical triangulations by Ambjorn and Jurkiewicz and by\nAgishtein and Migdal. We discuss a particular implementation of a Monte Carlo\nsimulation of simplicial quantum gravity. As an application we introduce a\nnon-uniform measure and examine its effect on simple aspects of the\nmathematical geometry. We find that the transition region from the hot to the\ncold phase is shifted and that the criticality of the transition changes."
    },
    {
        "anchor": "First Lattice Study of the $N$-$P_{11}(1440)$ Transition Form Factors: Experiments at Jefferson Laboratory, MIT-Bates, LEGS, Mainz, Bonn, GRAAL, and\nSpring-8 offer new opportunities to understand in detail how nucleon resonance\n($N^*$) properties emerge from the nonperturbative aspects of QCD. Preliminary\ndata from CLAS collaboration, which cover a large range of photon virtuality\n$Q^2$ show interesting behavior with respect to $Q^2$ dependence: in the region\n$Q^2 \\le 1.5 {GeV}^2$, both the transverse amplitude, $A_{1/2}(Q^2)$, and the\nlongitudinal amplitude, $S_{1/2}(Q^2)$, decrease rapidly. In this work, we\nattempt to use first-principles lattice QCD (for the first time) to provide a\nmodel-independent study of the Roper-nucleon transition form factor.",
        "positive": "Staggered Heavy Baryon Chiral Perturbation Theory: Although taste violations significantly affect the results of staggered\ncalculations of pseudoscalar and heavy-light mesonic quantities, those entering\nstaggered calculations of baryonic quantities have not been quantified. Here I\ndevelop staggered chiral perturbation theory in the light-quark baryon sector\nby mapping the Symanzik action into heavy baryon chiral perturbation theory.\nFor 2+1 dynamical quark flavors, the masses of flavor-symmetric nucleons are\ncalculated to third order in partially quenched and fully dynamical staggered\nchiral perturbation theory. To this order the expansion includes the leading\nchiral logarithms, which come from loops with virtual decuplet-like states, as\nwell as terms the order of the cubed pion mass, which come from loops with\nvirtual octet-like states. Taste violations enter through the meson propagators\nin loops and tree-level terms the order of the squared lattice spacing. The\npattern of taste symmetry breaking and the resulting degeneracies and mixings\nare discussed in detail. The resulting chiral forms are appropriate to lattice\nresults obtained with operators already in use and could be used to study the\nrestoration of taste symmetry in the continuum limit. I assume that the fourth\nroot of the fermion determinant can be incorporated in staggered chiral\nperturbation theory using the replica method."
    },
    {
        "anchor": "Lattice QCD and Three-Body Exotic Systems in the static limit: The static potentials for quark-antiquark-gluon and 3-gluon systems are\ncomputed with lattice QCD methods. For the quark-antiquark-gluon hybrid meson\nthe static potential is obtained for different values of the angle between the\nquark-gluon and antiquark-gluon segments. The simulations support the formation\nof an adjoint string for small angles, while for large angles, the adjoint\nstring is replaced by two fundamental strings connecting the gluon and the\nquarks. For the 3-gluon glueball, we discuss the corresponding Wilson loops and\nshow that the gluons are connected by fundamental strings when the gluons are\nfar apart.",
        "positive": "Effects of a potential fourth fermion generation on the Higgs boson mass\n  bounds: We study the effect of a potential fourth fermion generation on the upper and\nlower Higgs boson mass bounds. This investigation is based on the numerical\nevaluation of a chirally invariant lattice Higgs-Yukawa model emulating the\nsame Higgs-fermion coupling structure as in the Higgs sector of the electroweak\nStandard Model. In particular, the considered model obeys a Ginsparg-Wilson\nversion of the underlying $SU(2)_L\\times U(1)_Y$ symmetry, being a global\nsymmetry here due to the neglection of gauge fields in this model. We present\nour results on the modification of the upper and lower Higgs boson mass bounds\ninduced by the presence of a hypothetical very heavy fourth quark doublet.\nFinally, we compare these findings to the standard scenario of three fermion\ngenerations."
    },
    {
        "anchor": "Half-integer topological charges below and above the deconfinement\n  transition?: For pure SU(2) lattice gauge theory at finite T, by the help of the cooling\nmethod, we search for classical (approximate) solutions having non-trivial\nholonomy at the spatial boundary. We identify various typical objects and\nprovide their relative frequency of occurence for the confinement and\ndeconfinement phases. Among the configurations obtained we see also the\ndissociated BPS monopole pairs recently discussed by van Baal and\ncollaborators.",
        "positive": "Inverse magnetic catalysis and the Polyakov loop: We study the physical mechanism of how an external magnetic field influences\nthe QCD quark condensate. Two competing mechanisms are identified, both relying\non the interaction between the magnetic field and the low quark modes. While\nthe coupling to valence quarks enhances the condensate, the interaction with\nsea quarks suppresses it in the transition region. The latter `sea effect' acts\nby ordering the Polyakov loop and, thereby, reduces the number of small Dirac\neigenmodes and the condensate. It is most effective around the transition\ntemperature, where the Polyakov loop effective potential is flat and a small\ncorrection to it by the magnetic field can have a significant effect. Around\nthe critical temperature, the sea suppression overwhelms the valence\nenhancement, resulting in a net suppression of the condensate, named inverse\nmagnetic catalysis. We support this physical picture by lattice simulations\nincluding continuum extrapolated results on the Polyakov loop as a function of\ntemperature and magnetic field. We argue that taking into account the increase\nin the Polyakov loop and its interaction with the low-lying modes is essential\nto obtain the full physical picture, and should be incorporated in effective\nmodels for the description of QCD in magnetic fields in the transition region."
    },
    {
        "anchor": "Full determination of the CKM matrix using recent results from lattice\n  QCD: A full determination of the CKM matrix using recent results from lattice QCD\nis presented. To extract the CKM matrix in a uniform fashion, I exclusively use\nresults from unquenched lattice QCD as the theory input for nonperturbative QCD\neffects. All 9 CKM matrix elements and all 4 Wolfenstein parameters are\nobtained from results for gold-plated quantities, which include semileptonic\ndecay form factors and leptonic decay constants of B, D and K mesons, and\nB^0-\\bar{B}^0 and K^0-\\bar{K}^0 mixing amplitudes.",
        "positive": "A New Gauge Fixing Method for Abelian Projection: We formulate a stochastic gauge fixing method to study the gauge dependence\nof the Abelian projection. We consider a gauge which interpolates between the\nmaximal Abelian gauge and no gauge fixing. We have found that Abelian dominance\nfor the heavy quark potential holds even in a gauge which is far from maximally\nAbelian one. The heavy quark potentials from monopole and photon contribution\nare calculated at several values of the gauge parameter, and the former part\nshows always the confinement behavior."
    },
    {
        "anchor": "Monopoles in Real Time for Classical U(1) Gauge Field Theory: U(1) gauge fields are decomposed into a monopole and photon part across the\nphase transition from the confinement to the Coulomb phase. We analyze the\nleading Lyapunov exponents of such gauge field configurations on the lattice\nwhich are initialized by quantum Monte Carlo simulations. We observe that the\nmonopole field carries the same Lyapunov exponent as the original U(1) field.\nAs a long awaited result, we show that monopoles are created and annihilated in\npairs as a function of real time in excess to a fixed average monopole number.",
        "positive": "Two-Baryon Systems with Twisted Boundary Conditions: We explore the use of twisted boundary conditions in extracting the nucleon\nmass and the binding energy of two-baryon systems, such as the deuteron, from\nLattice QCD calculations. Averaging the results of calculations performed with\nperiodic and anti-periodic boundary conditions imposed upon the light-quark\nfields, or other pair-wise averages, improves the volume dependence of the\ndeuteron binding energy from ~exp(-kappa*L)/L to ~exp(-sqrt(2)kappa*L)/L.\nHowever, a twist angle of pi/2 in each of the spatial directions improves the\nvolume dependence from ~exp(-kappa*L)/L to ~exp(-2kappa*L)/L. Twist averaging\nthe binding energy with a random sampling of twist angles improves the volume\ndependence from ~exp^(-kappa*L)/L to ~exp(-2kappa*L)/L, but with a standard\ndeviation of ~exp(-kappa*L)/L, introducing a signal-to-noise issue in modest\nlattice volumes. Using the experimentally determined phase shifts and mixing\nangles, we determine the expected energies of the deuteron states over a range\nof cubic lattice volumes for a selection of twisted boundary conditions."
    },
    {
        "anchor": "Complex Langevin studies of the dynamical compactification of extra\n  dimensions in the Euclidean IKKT matrix model: The type IIB matrix model, also known as the IKKT matrix model, is a\npromising candidate for a nonperturbative formulation of superstring theory. In\nthis talk we study the Euclidean version of the IKKT matrix model, which has a\n\"sign problem\" due to the Pfaffian coming from integrating out the fermionic\ndegrees of freedom. To study the spontaneous breaking of the SO(10) rotational\nsymmetry, we apply the Complex Langevin Method (CLM) to the Euclidean IKKT\nmatrix model. We conclude that the SO(10) symmetry is broken to SO(3), in\nagreement with the previous studies by the Gaussian Expansion Method (GEM). We\nalso apply the GEM to the deformed model and find consistency with the CLM\nresult. These are proceedings of Takehiro Azuma's talk at Asia-Pacific\nSymposium for Lattice Field Theory (APLAT 2020) on August 4-7, 2020, based on\nthe paper arXiv:2002.07410.",
        "positive": "The Forgotten Potts Models: The q=10 and q=200 state Potts models coupled to 2d gravity are investigated\nnumerically and shown to have continuous phase transitions, contrary to their\nbehavior on a regular lattice. Critical exponents are extracted and possible\ncritical behavior for general q-state Potts models coupled to gravity is\ndiscussed."
    },
    {
        "anchor": "The density of states in gauge theories: The density of states is calculated for a SU(2) and a compact U(1) lattice\ngauge theory using a modified version of the Wang-Landau algorithm. We find\nthat the density of states of the SU(2) gauge theory can be reliably calculated\nover a range of 120,000 orders of magnitude for lattice sizes as big as 20^4.\nWe demonstrate the potential of the algorithm by reproducing the SU(2) average\naction, its specific heat and the critical couplings of the weak first order\ntransition in U(1).",
        "positive": "Large-N reduction in QCD with two adjoint Dirac fermions: We use lattice simulations to study the single-site version of SU(N) lattice\ngauge theory with two flavors of Wilson-Dirac fermions in the adjoint\nrepresentation, a theory whose large volume correspondent is expected to be\nconformal or nearly conformal. Working with N as large as 53, we map out the\nphase diagram in the plane of bare `t Hooft coupling, g^2 N, and of the lattice\nquark mass, a*m, and look for the region where the Z_N^4 center symmetry of the\ntheory is intact. In this region one expects the large-N equivalence of the\nsingle site and infinite volume theories to be valid. As for the N_f=1 case\n(see Phys. Rev. D80: 065031), we find that the center-symmetric region is large\nand includes both light fermion masses and masses at the cutoff scale. We study\nthe N-dependence of the width of this region and find strong evidence that it\nremains of finite width as N goes to infinity. Simulating with couplings as\nsmall as g^2 N = 0.005, we find that the width shrinks slowly with decreasing\ng^2 N, at a rate consistent with analytic arguments. Within the\ncenter-symmetric region our results for the phase structure, when extrapolated\nto infinite N, apply also for the large volume theory, which is minimal walking\ntechnicolor with N=infinity. We find a first-order transition as a function of\na*m for all values of b, which we argue favors that the theory is confining in\nthe infrared. Finally, we measure the eigenvalue densities of the Wilson-Dirac\noperator and its hermitian version, and use large Wilson loops to study the\nutility of reduction for extracting physical observables."
    },
    {
        "anchor": "$B \\to D^*\\ell\u03bd_\\ell$ semileptonic form factors from lattice QCD with\n  M\u00f6bius domain-wall quarks: We calculate the form factors for the $B \\to D^*\\ell\\nu_\\ell$ decay in 2+1\nflavor lattice QCD. For all quark flavors, we employ the M\\\"obius domain-wall\naction, which preserves chiral symmetry to a good precision. Our gauge\nensembles are generated at three lattice cutoffs $a^{-1} \\sim 2.5$, 3.6 and 4.5\nGeV with pion masses as low as $M_\\pi \\sim 230$ MeV. The physical lattice size\n$L$ satisfies the condition $M_\\pi L \\geq 4$ to control finite volume effects\n(FVEs), while we simulate a smaller size at the smallest $M_\\pi$ to directly\nexamine FVEs. The bottom quark masses are chosen in a range from the physical\ncharm quark mass to $0.7 a^{-1}$ to control discretization effects. We\nextrapolate the form factors to the continuum limit and physical quark masses\nbased on heavy meson chiral perturbation theory at next-to-leading order. Then\nthe recoil parameter dependence is parametrized using a model independent form\nleading to our estimate of the decay rate ratio between the tau ($\\ell = \\tau$)\nand light lepton ($\\ell = e,\\mu$) channels $R(D^*) = 0.252(22)$ in the Standard\nModel. A simultaneous fit with recent data from the Belle experiment yields\n$|V_{cb}| = 39.19(90)\\times 10^{-3}$, which is consistent with previous\nexclusive determinations, and shows good consistency in the kinematical\ndistribution of the differential decay rate between the lattice and\nexperimental data.",
        "positive": "On the sign problem in 2D lattice super Yang--Mills: In recent years a new class of supersymmetric lattice theories have been\nproposed which retain one or more exact supersymmetries for non-zero lattice\nspacing. Recently there has been some controversy in the literature concerning\nwhether these theories suffer from a sign problem. In this paper we address\nthis issue by conducting simulations of the N=(2, 2) and N=(8, 8)\nsupersymmetric Yang--Mills theories in two dimensions for the U(N) theories\nwith N=2,3,4, using the new twisted lattice formulations. Our results provide\nevidence that these theories do not suffer from a sign problem in the continuum\nlimit. These results thus boost confidence that the new lattice formulations\ncan be used successfully to explore non-perturbative aspects of\nfour-dimensional N=4 supersymmetric Yang--Mills theory."
    },
    {
        "anchor": "Electric polarizability of hadrons with overlap fermions on multi-GPUs: Electric polarizability is an important parameter for the internal structure\nof hadrons. Previous studies of polarizabilities have been done at relatively\nheavy pion masses, leaving the chiral region largely unexplored. In this\nreport, we use overlap fermions which are known to be computationally demanding\nto properly capture the chiral dynamics. We present an implementation strategy\nto construct overlap on multi-GPUs. We find that our GPU code has an equivalent\nof \\sim30 CPU cores to 1 GPU. We also present preliminary results for the\npolarizability of the neutral pion.",
        "positive": "Fermion zero mode associated with instantonlike self-dual solution to\n  lattice Euclidean gravity: We prove the existence of lattice fermion zero mode associated with self-dual\nlattice gravity solution."
    },
    {
        "anchor": "Mass spectrum and decay constants in the continuum limit: We present first results for light hadron masses, quark masses and decay\nconstants in the continuum limit using O(a) improved fermions at three\ndifferent values of the gauge coupling \\beta.",
        "positive": "The Charm Quark Mass to Two-Loop Order: The truncation of the perturbative series at one loop order for the mass\nrenormalization constants remain a significant systematic uncertainty in the\ndetermination of heavy quark masses in lattice QCD. We present here a high beta\nMonte Carlo calculation of the two loop mass renormalization constant for\nclover-improved fermions near the charm mass in the Fermilab heavy quark\nformalism. A preliminary value for the charm quark mass in the MS-bar scheme at\ntwo loop order is reported."
    },
    {
        "anchor": "Improvement and Renormalization Constants in O(a) Improved Lattice QCD: We present results at beta=6.0 and 6.2 for the O(a) improvement and\nrenormalization constants for bilinear operators using axial and vector Ward\nidentities. We discuss the extraction of the mass dependence of the\nrenormalization constants and the coefficients of the equation of motion\noperators.",
        "positive": "A first analysis of the ensemble of local maxima of maximal center gauge: Maximal center gauge (MCG) aims to detect some of the most important vacuum\nconfigurations, suggesting thick magnetic flux tubes quantised to non-trivial\ncenter elements of the gauge group being responsible for confinement. Due to\nthe NP-hardness of a global maximization of the gauge functional only numeric\nprocedures aiming for local maxima are possible. We observe a linear decrease\nof the string tension with increasing gauge functional value of the local\nmaxima. This implies that the request to get as close as possible to the\nabsolute maximum is untainable. We compare global properties of the ensemble of\nlocal maxima with other methods to detect center vortices and with\ndeterminations of the string tension from full configurations. This comparison\nindicates that the information about the number and positions of center\nvortices is contained in the structure of the ensemble of local maxima. This\nmay pave the way for a future more successful formulation of the gauge\ncondition."
    },
    {
        "anchor": "Topological gravity on the lattice: In this paper we show that a particular twist of $\\mathcal{N}=4$ super\nYang-Mills in three dimensions with gauge group SU(2) possesses a set of\nclassical vacua corresponding to the space of flat connections of the {\\it\ncomplexified} gauge group $SL(2,C)$. The theory also contains a set of\ntopological observables corresponding to Wilson loops wrapping non-trivial\ncycles of the base manifold. This moduli space and set of topological\nobservables is shared with the Chern Simons formulation of three dimensional\ngravity and we hence conjecture that the Yang-Mills theory gives an equivalent\ndescription of the gravitational theory. Unlike the Chern Simons formulation\nthe twisted Yang-Mills theory possesses a supersymmetric and gauge invariant\nlattice construction which then provides a possible non-perturbative definition\nof three dimensional gravity.",
        "positive": "Stochastic quantization at nonzero chemical potential: Lattice QCD at finite chemical potential is difficult due to the sign\nproblem. We use stochastic quantization and complex Langevin dynamics to study\nthis issue. First results for QCD in the hopping expansion are encouraging.\nU(1) and SU(3) one link models are used to gain further insight into why the\nmethod appears to be successful."
    },
    {
        "anchor": "The Beauty of Lattice Perturbation Theory: The Role of Lattice\n  Perturbation Theory in B Physics: As new experimental data arrive from the LHC the prospect of indirectly\ndetecting new physics through precision tests of the Standard Model grows more\nexciting. Precise experimental and theoretical inputs are required to test the\nunitarity of the CKM matrix and to search for new physics effects in rare\ndecays. Lattice QCD calculations of nonperturbative inputs have reached a\nprecision at the level of a few percent; in many cases aided by the use of\nlattice perturbation theory. This review examines the role of lattice\nperturbation theory in B physics calculations on the lattice in the context of\ntwo questions: how is lattice perturbation theory used in the different heavy\nquark formalisms implemented by the major lattice collaborations? And what role\ndoes lattice perturbation theory play in determinations of nonperturbative\ncontributions to the physical processes at the heart of the search for new\nphysics? Framing and addressing these questions reveals that lattice\nperturbation theory is a tool with a spectrum of applications in lattice B\nphysics.",
        "positive": "Four-loop logarithms in 3d gauge + Higgs theory: We discuss the logarithmic contributions to the vacuum energy density of the\nthree-dimensional SU(3) + adjoint Higgs theory in its symmetric phase, and\nrelate them to numerical Monte Carlo simulations. We also comment on the\nimplications of these results for perturbative and non-perturbative\ndeterminations of the pressure of finite-temperature QCD."
    },
    {
        "anchor": "Lattice Landau gauge quark propagator at finite temperature: We study the Landau gauge quark propagator, at finite temperature, using\nquenched lattice simulations. Special focus is given to the behaviour of the\nmomentum space form factors across the confinement-deconfinement phase\ntransition.",
        "positive": "Semi-Leptonic Decays of $B$-Mesons: Form factors relevant for semi-leptonic $B\\to D,\\ D^*$ decays are obtained in\nquenched lattice QCD. Tests of heavy-quark symmetry as well as determinations\nof the Isgur-Wise function and $|V_{cb}|$ are presented."
    },
    {
        "anchor": "QCD at Finite temperature and density with staggered and Wilson quarks: One of the most challenging issues in particle physics is to study QCD in\nextreme conditions. Precise determination of the QCD phase diagram on\ntemperature $T$ and chemical potential $\\mu$ plane will provide valuable\ninformation for quark-gluon plasma (QGP) and neutron star physics. We present\nresults for phase structure on the $(\\mu, T)$ plane for lattice QCD with Wilson\nfermions from strong coupling Hamiltonian analysis and Kogut-Susskind Fermions\nfrom Lagrangian Monte Carlo simulations at intermediate coupling.",
        "positive": "Gauge fixing and the gluon propagator in renormalizable xi gauges: Covariant $R_\\xi$ gauge fixing is notoriously difficult for large lattice\nvolumes, large $\\xi$ and small $N_c$. We thoroughly test different convergence\ntechniques, which allows the gauge fixing of lattice configurations with a\ntotal volume of (3.25 fm)$^4$, up to $\\xi=0.5$. We are able to study the gluon\npropagator in the infrared region and its dependence on the gauge fixing\nparameter $\\xi$. As expected, the longitudinal gluon dressing functions stay\nconstant at their tree-level value $\\xi$. Similar to the Landau gauge, the\ntransverse $R_\\xi$ gauge gluon propagators saturate at a non-vanishing value in\nthe deep infrared for all values of $\\xi$ studied. We compare with very recent\ncontinuum studies and perform a simple analysis of the found saturation with a\ndynamically generated effective gluon mass."
    },
    {
        "anchor": "Critical specific heats of the N-vector spin models on the sc and the\n  bcc lattices: We have computed through order $\\beta^{21}$ the high-temperature expansions\nfor the nearest-neighbor spin correlation function $G(N,\\beta)$ of the\nclassical N-vector model, with general N, on the simple-cubic and on the\nbody-centered-cubic lattices.\n  For this model, also known in quantum field theory as the lattice O(N)\nnonlinear sigma model, we have presented in previous papers extended expansions\nof the susceptibility, of its second field derivative and of the second moment\nof the correlation function.\n  Here we study the internal specific energy and the specific heat\n$C(N,\\beta)$, obtaining new estimates of the critical parameters and therefore\na more accurate direct test of the hyperscaling relation $d \\nu(N)=2 -\n\\alpha(N)$ on a range of values of the spin dimensionality N, including N=0\n[the self-avoiding walk model], N=1 [the Ising spin 1/2 model], N=2 [the XY\nmodel], N=3 [the classical Heisenberg model]. By the newly extended series, we\nalso compute the universal combination of critical amplitudes usually denoted\nby $R^+_{\\xi}(N)$, in fair agreement with renormalization group estimates.",
        "positive": "Two-Flavor Staggered Fermion Thermodynamics at N_t = 12: We present results of an ongoing study of the nature of the high temperature\ncrossover in QCD with two light fermion flavors. These results are obtained\nwith the conventional staggered fermion action at the smallest lattice spacing\nto date---approximately 0.1 fm. Of particular interest are a study of the\ntemperature of the crossover a determination of the induced baryon charge and\nbaryon susceptibility, the scalar susceptibility, and the chiral order\nparameter, used to test models of critical behavior associated with chiral\nsymmetry restoration. From our new data and published results for N_t = 4, 6,\nand 8, we determine the QCD magnetic equation of state from the chiral order\nparameter using O(4) and mean field critical exponents and compare it with the\ncorresponding equation of state obtained from an O(4) spin model and mean field\ntheory. We also present a scaling analysis of the Polyakov loop, suggesting a\ntemperature dependent ``constituent quark free energy.''"
    },
    {
        "anchor": "Multigrid for Wilson Clover Fermions in Grid: With the ever-growing number of computing architectures, performance\nportability is an important aspect of (Lattice QCD) software. The Grid library\nprovides a good framework for writing such code, as it thoroughly separates\nhardware-specific code from algorithmic functionality and already supports many\nmodern architectures. We describe the implementation of a multigrid solver for\nWilson clover fermions in Grid by the RQCD group. We present the features\nincluded in our implementation, discuss initial optimization efforts, and\ncompare the performance with another multigrid implementation.",
        "positive": "Dynamical overlap fermion at fixed topology: We launched a project to perform dymanical fermion simulations using the\noverlap fermion formulation for sea quarks. In order to avoid the appearace of\nnear-zero modes of the hermitian Wilson-Dirac operator $H_W$, we introduce a\npair of extra Wilson fermions with a large negative mass term. Crossing of the\ntopological boundary is then strictly prohibited, and the topological charge is\nconserved during simulations. It makes the simulations substantially faster\ncompared to the algorithms which allow the topology change. We discuss on the\nfinite volume effects due to the fixed global topology."
    },
    {
        "anchor": "Laplacian modes as a filter: We compute low-lying eigenmodes of the gauge covariant Laplace operator on\nthe lattice at finite temperature. For classical configurations we show how the\nlowest mode localizes the monopole constituents inside calorons and that it\nhops upon changing the boundary conditions. The latter effect we observe for\nthermalized backgrounds, too, analogously to what is known for fermion zero\nmodes.\n  We propose a new filter for equilibrium configurations which provides link\nvariables as a truncated sum involving the Laplacian modes. This method not\nonly reproduces classical structures, but also preserves the confining\npotential, even when only a few modes are used.",
        "positive": "The Spectrum of the 2+1 Dimensional Gauge Ising Model: We present a high precision Monte Carlo study of the spectrum of the $Z_2$\ngauge theory in $2+1$ dimensions in the strong coupling phase. Using state of\nthe art Monte Carlo techniques we are able to accurately determine up to three\nmasses in a single channel. We compare our results with the strong coupling\nexpansion for the lightest mass and with results for the universal ratio\n$\\sigma/m^2$ determined for the $\\phi^4$-theory. Finally the whole spectrum is\ncompared with that obtained from the Isgur-Paton flux tube model and the\nspectrum of the $2+1$ dimensional $SU(2)$ gauge theory. A remarkable agreement\nbetween the Ising and SU(2) spectra (except for the lowest mass state) is\nfound."
    },
    {
        "anchor": "Bosonization and the lattice Gross-Neveu model: We consider a lattice version of the bosonized Gross-Neveu model. It is\nexplicitely chiral symmetric and its numerical simulation does not involve any\nanticommuting field. We study its non trivial $1/N$ expansion up to the\nnext-to-leading term comparing the results with explicit numerical simulations.",
        "positive": "Parallel Supercomputing PC Cluster and Some Physical Results in Lattice\n  QCD: We describe the construction of a high performance parallel computer composed\nof PC components, present some physical results for light hadron and hybrid\nmeson masses from lattice QCD. We also show that the smearing technique is very\nuseful for improving the spectrum calculations."
    },
    {
        "anchor": "Spectrum of k-string tensions in SU(N) gauge theories: We compute, for the four-dimensional SU(4) and SU(6) gauge theories\nformulated on a lattice, the string tensions sigma_k related to sources with\nZ_N charge k, using Monte Carlo simulations. Our results are compatible with\nsigma_k \\propto sin (k pi/N), and show sizeable deviations from Casimir\nscaling.",
        "positive": "Pion Valence-Quark Generalized Parton Distribution at Physical Pion Mass: We present the first lattice-QCD $x$-dependent pion valence-quark generalized\nparton distribution (GPD) calculated directly at physical pion mass using the\nLarge-Momentum Effective Theory (LaMET) with next-to-next-to-leading order\nperturbative matching correction. We use clover fermions for the valence action\non $2+1+1$ flavors of highly improved staggered quarks (HISQ), generated by\nMILC Collaboration, with lattice spacing $a \\approx 0.09$fm and box size $L\n\\approx 5.5$fm; the pion two-point measurements number up to $O(10^6)$ with\nboost momentum 1.73GeV. The pion valence distribution is renormalized in hybrid\nscheme with Wilson-line mass subtraction at large distances in coordinate\nspace, followed by a procedure to match it to the $\\overline{\\text{MS}}$\nscheme. We focus on the zero-skewness limit, where the GPD has a\nprobability-density interpretation in the longitudinal Bjorken $x$ and the\ntransverse impact-parameter distributions. We take the integral of our GPD\nfunctions to generate leading moment so that we can make comparisons with past\nlattice-QCD and experimental determinations of the pion form factors and found\nconsistent agreement among them. We predict the higher GPD moments and reveal\n$x$-dependent tomography of the pion for the first time using lattice QCD."
    },
    {
        "anchor": "Plaquette representation for 3D lattice gauge models: I. Formulation and\n  perturbation theory: We develop an analytical approach for studying lattice gauge theories within\nthe plaquette representation where the plaquette matrices play the role of the\nfundamental degrees of freedom. We start from the original Batrouni formulation\nand show how it can be modified in such a way that each non-abelian Bianchi\nidentity contains only two connectors instead of four. In addition, we include\ndynamical fermions in the plaquette formulation. Using this representation we\nconstruct the low-temperature perturbative expansion for U(1) and SU(N) models\nand discuss its uniformity in the volume. The final aim of this study is to\ngive a mathematical background for working with non-abelian models in the\nplaquette formulation.",
        "positive": "An efficient algorithm for numerical computations of continuous\n  densities of states: In Wang-Landau type algorithms, Monte-Carlo updates are performed with\nrespect to the density of states, which is iteratively refined during\nsimulations. The partition function and thermodynamic observables are then\nobtained by standard integration. In this work, our recently introduced method\nin this class (the LLR approach) is analysed and further developed. Our\napproach is a histogram free method particularly suited for systems with\ncontinuous degrees of freedom giving rise to a continuum density of states, as\nit is commonly found in Lattice Gauge Theories and in some Statistical\nMechanics systems. We show that the method possesses an exponential error\nsuppression that allows us to estimate the density of states over several\norders of magnitude with nearly-constant {\\it relative} precision. We explain\nhow ergodicity issues can be avoided and how expectation values of arbitrary\nobservables can be obtained within this framework. We then demonstrate the\nmethod using Compact U(1) Lattice Gauge Theory. A thorough study of the\nalgorithm parameter dependence of the results is performed and compared with\nthe analytically expected behaviour. We obtain high precision values for the\ncritical coupling for the phase transition and for the peak value of the\nspecific heat for lattice sizes ranging from $8^4$ to $20^4$. Our results\nperfectly agree with the reference values reported in the literature, which\ncovers lattice sizes up to $18^4$. Robust results for the $20^4$ volume are\nobtained for the first time. This latter investigation, which, due to strong\nmetastabilities developed at the pseudo-critical coupling, so far has been out\nof reach even on supercomputers with importance sampling approaches, has been\nperformed to high accuracy with modest computational resources. Other\nsituations where the method is expected to be superior to importance sampling\ntechniques are pointed out."
    },
    {
        "anchor": "Large-N reduction with adjoint Wilson fermions: We analyze the large-N behavior of SU(N) lattice gauge theories with adjoint\nfermions by studying volume-reduced models, as pioneered by Eguchi and Kawai.\nWe perform simulations on a single-site lattice for Nf = 1 and Nf = 2 Wilson\nDirac fermions with values of N up to 53. We show for both values of Nf that in\nthe large-N limit there is a finite region, containing both light and heavy\nfermions, of unbroken center symmetry where the theory exhibits volume\nindependence. Using large-N reduction we attempt to calculate physical\nquantities such as the string tension and meson masses.",
        "positive": "Infrared exponents of gluon and ghost propagators from Lattice QCD: The compatibility of the pure power law infrared solution of QCD\nDyson-Schwinger equations (DSE) and lattice data for the gluon and ghost\npropagators in Landau gauge is discussed. For the gluon propagator, the lattice\ndata is compatible with the DSE infrared solution with an exponent\n$\\kappa\\sim0.53$, measured using a technique that suppresses finite volume\neffects and allows to model these corrections to the lattice data. For the\nghost propagator, the lattice data does not seem to follow the infrared DSE\npower law solution."
    },
    {
        "anchor": "Renormalization of Bilinear Quark Operators for Overlap Fermions: We present non-perturbative renormalization constants of fermionic bilinears\non the lattice in the quenched approximation at beta=6.1 using an overlap\nfermion action with hypercubic(HYP)-blocked links. We consider the effects of\nthe exact zero modes of the Dirac operator and find they are important in\ncalculating the renormalization constants of the scalar and pseudoscalar\ndensity. The results are given in the RI' and MS bar schemes and compared to\nthe perturbative calculations.",
        "positive": "Exploratory study of the off-shell properties of the weak vector bosons: Gauge invariance requires even in the weak interactions that physical,\nobservable particles are described by gauge-invariant composite operators. Such\noperators have the same structure as those describing bound states, and\nconsequently the physical versions of the $W^\\pm$, the $Z$, and the Higgs\nshould have some kind of substructure. To test this consequence, we use lattice\ngauge theory to study the physical weak vector bosons off-shell, especially\ntheir form-factor and weak radius, and compare the results to the ones for the\nelementary particles. We find that the physical particles show substantial\ndeviations from the structure of a point-like particle. At the same time the\ngauge-dependent elementary particles exhibit unphysical behavior."
    },
    {
        "anchor": "Chiral Magnetic Effect on the Lattice: We review recent progress on the lattice simulations of the chiral magnetic\neffect. There are two different approaches to analyze the chiral magnetic\neffect on the lattice. In one approach, the charge density distribution or the\ncurrent fluctuation is measured under a topological background of the gluon\nfield. In the other approach, the topological effect is mimicked by the chiral\nchemical potential, and the induced current is directly measured. Both\napproaches are now developing toward the exact analysis of the chiral magnetic\neffect.",
        "positive": "Hadron Physics and Lattice QCD: A review of recent lattice QCD hadron structure calculations is presented.\nImportant hadronic properties such as the axial charge and spin content of the\nnucleon, as well as, the mass and axial charge of hyperons and charmed baryons\nare discussed."
    },
    {
        "anchor": "Scaling and the continuum limit of gluoN_c plasmas: We investigated the finite temperature (T) phase transition for SU(Nc) gauge\ntheory with Nc=4, 6, 8 and 10 at lattice spacing, a, of 1/(6T) or less. We\nfound that these theories have first order transitions at such small a. In many\ncases we were able to find the critical couplings with precision as good as a\nfew parts in 10^4. We also investigated the use of two-loop renormalization\ngroup equations in extrapolating the lattice results to the continuum, thus\nfixing the temperature scale in units of the phase transition temperature, Tc.\nWe found that when a \\le 1/(8Tc) the two-loop extrapolation was accurate to\nabout 1--2%. However, we found that trading Tc for the QCD scale, Lambda_MSbar,\nincreases uncertainties significantly, to the level of about 5--10%.",
        "positive": "Employing the perturbative definition of the Higgs mass in a\n  non-perturbative calculation: In perturbative calculations the masses of the Higgs, the Ws and the Z are\nusually determined from the pole position of the corresponding gauge-dependent\npropagators. In full non-perturbative lattice calculations it is much more\ndirect to instead investigate the bound state spectrum with its\ngauge-independent meaning, which then contains bound states of Higgses and/or\nWs and Zs. It is possible to extend the perturbative definition of the Higgs\nmass also to such a full non-perturbative setting by determining the respective\nfull non-perturbative propagators of the Higgs, the Ws, and the Z, and analyze\ntheir analytic structure. This helps connecting the Higgs properties indirectly\nwith gauge-invariant physics. This is here studied, using lattice gauge theory,\nfor the case of a W-Z-Higgs system."
    },
    {
        "anchor": "Fixed Point Actions for Wilson Fermions: Iterating renormalization group transformations for lattice fermions the\nWilson action is driven to fixed points of the renormalization group. A line of\nfixed points is found and the fixed point actions are computed analytically.\nThey are local and may be used to improve scaling in lattice QCD. The action at\nthe line's endpoint is chirally invariant and still has no fermion doubling.\nThe Nielsen-Ninomiya theorem is evaded because in this case the fixed point\naction is nonlocal. The use of this action for a construction of lattice chiral\nfermions is discussed.",
        "positive": "The preliminary lattice QCD calculation of $\u03ba$ meson decay width: We present a direct lattice QCD calculation of the $\\kappa$ meson decay width\nwith the s-wave scattering phase shift for the isospin $I=1/2$ pion-kaon ($\\pi\nK$) system. We employ a special finite size formula, which is the extension of\nthe Rummukainen-Gottlieb formula for the $\\pi K$ system in the moving frame, to\ncalculate the scattering phase, which indicates a resonance around $\\kappa$\nmeson mass. Through the effective range formula, we extract the effective\n$\\kappa \\to \\pi K$ coupling constant $g_{\\kappa \\pi K} = 4.54(76)$ GeV and\ndecay width $\\Gamma = 293 \\pm 101$ MeV. Our simulations are done with the MILC\ngauge configurations with $N_f=2+1$ flavors of the \"Asqtad\" improved staggered\ndynamical sea quarks on a $16^3\\times48$ lattice at $(m_\\pi + m_K) / m_\\kappa\n\\approx 0.8$ and lattice spacing $a \\approx 0.15$ fm."
    },
    {
        "anchor": "An analogue to the pion decay constant in the multi-flavor Schwinger\n  model: We study the Schwinger model with $N_{\\rm f} \\geq 2$ degenerate fermion\nflavors, by means of lattice simulations. We use dynamical Wilson fermions for\n$N_{\\rm f} = 2$, and re-weighted quenched configurations for overlap-hypercube\nfermions with $N_{\\rm f} \\leq 6$. In this framework, we explore an analogue of\nthe QCD pion decay constant $F_{\\pi}$, which is dimensionless in $d=2$, and\nwhich has hardly been considered in the literature. We determine $F_{\\pi}$ by\nthree independent methods, with numerical and analytical ingredients. First, we\nconsider the 2-dimensional version of the Gell-Mann--Oakes--Renner relation,\nwhere we insert both theoretical and numerical values for the quantities\ninvolved. Next we refer to the $\\delta$-regime, {\\it i.e.\\ a small spatial\nvolume, where we assume formulae from Chiral Perturbation Theory to apply even\nin the absence of Nambu-Goldstone bosons. We further postulate an effective\nrelation between $N_{\\rm f}$ and the number of relevant, light bosons, which we\ndenote as \"pions\". Thus $F_{\\pi}$ is obtained from the residual \"pion\" mass in\nthe chiral limit, which is a finite-size effect. Finally, we address to the\n2-dimensional Witten--Veneziano formula: it yields a value for $F_{\\eta}$,\nwhich we identify with $F_{\\pi}$, as in large-$N_{\\rm c}$ QCD. All three\napproaches consistently lead to $F_{\\pi} \\simeq 1/\\sqrt{2 \\pi}$ at fermion mass\n$m=0$, which implies that this quantity is meaningful.",
        "positive": "The gradient flow running coupling in SU2 with 8 flavors: We present preliminary results of the gradient flow running coupling with\nDirichlet boundary condition in the SU(2) gauge theory with 8 fermion flavours.\nImprovements to the gradient flow measurement allow us to obtain a robust\ncontinuum limit. The results are consistent with perturbative running in the\nweak coupling region."
    },
    {
        "anchor": "Microcanonical cluster algorithms: I propose a numerical simulation algorithm for statistical systems which\ncombines a microcanonical transfer of energy with global changes in clusters of\nspins. The advantages of the cluster approach near a critical point augment the\nspeed increases associated with multi-spin coding in the microcanonical\napproach. The method also provides a limited ability to tune the average\ncluster size.",
        "positive": "Nucleon decay matrix elements with the Wilson quark action: an update: We present preliminary results of a new lattice computation of hadronic\nmatrix elements of baryon number violating operators which appear in the\nlow-energy effective Lagrangian of (SUSY-)Grand Unified Theories. The\ncontribution of irrelevant form factor which has caused an underestimate of the\nmatrix elements in previous studies is subtracted in this calculation. Our\nresults are 2$\\sim$4 times larger than the most conservative values often\nemployed in phenomenological analyses of nucleon decay with specific GUT\nmodels."
    },
    {
        "anchor": "More on the continuum limit of gauge-fixed compact U(1) lattice gauge\n  theory: We have verified various proposals that were suggested in our last paper\nconcerning the continuum limit of a compact formulation of the lattice U(1)\npure gauge theory in 4 dimensions using a nonperturbative gauge-fixed\nregularization. Our study reveals that most of the speculations are largely\ncorrect. We find clear evidence of a continuous phase transition in the pure\ngauge theory at \"arbitrarily\" large couplings. When probed with quenched\nstaggered fermions with U(1) charge, the theory clearly has a chiral transition\nfor large gauge couplings whose intersection with the phase transition in the\npure gauge theory continues to be a promising area for nonperturbative physics.\nWe probe the nature of the continuous phase transition by looking at gauge\nfield propagators in the momentum space and locate the region on the critical\nmanifold where free photons can be recovered.",
        "positive": "Short-time critical dynamics: An introductory review to short-time critical dynamics is given. From the\nscaling relation valid already in the early stage of the evolution of a system\nat or near the critical point, one derives power law behaviour for various\nquantities. By a numerical simulation of the system one can measure the\ncritical exponents and, by searching for the best power law behaviour, one can\ndetermine the critical point. Critical slowing down as well as finite size\ncorrections are nearly absent, since the correlation length is still small for\ntimes far before equilibrium is reached. By measuring the (pseudo) critical\npoints it is also possible to distinguish (weak) first-order from second-order\nphase transitions."
    },
    {
        "anchor": "Hadron Masses and Decay Constants with Wilson Quarks at $\u03b2=5.85$ and\n  6.0: We present results of a high statistics calculation of hadron masses and\nmeson decay constants in the quenched approximation to lattice QCD with Wilson\nquarks at $\\beta=$ 5.85 and 6.0 on $24^3 \\times 54$ lattices. We analyze the\ndata paying attention in particular to the systematic errors due to the choice\nof fitting range and due to the contamination from excited states. We find that\nthe systematic errors for the hadron masses with quarks lighter than the\nstrange quark amount to 1 --- 2 times the statistical errors. When the lattice\nscale is fixed from the $\\rho$ meson mass, the masses of the $\\Omega^{-}$\nbaryon and the $\\phi$ meson at two $\\beta$'s agree with experiment within about\none standard deviation. On the other hand, the central value of the nucleon\nmass at $\\beta=6.0$ (5.85) is larger than its experimental value by about 15\\%\n(20\\%) and that of the $\\Delta$ mass by about 15\\% (4\\%): Even when the\nsystematic errors are included, the baryon masses at $\\beta=6.0$ do not agree\nwith experiment. Vector meson decay constants at two values of $\\beta$ agree\nwell with each other and are consistent with experiment for a wide range of the\nquark mass, when we use current renormalization constants determined\nnonperturbatively by numerical simulations. The pion decay constant agrees with\nexperiment albeit with large errors. Results for the masses of excited states\nof the $\\rho$ meson and the nucleon are also presented.",
        "positive": "APE Results of Hadron Masses in Full QCD Simulations: We present numerical results obtained in full QCD with 2 flavors of Wilson\nfermions. We discuss the relation between the phase of Polyakov loops and the\n{\\bf sea} quarks boundary conditions. We report preliminary results about the\nHMC autocorrelation of the hadronic masses, on a $16^3 \\times 32$ lattice\nvolume, at $\\beta=5.55$ with $k_{sea}=0.1570$."
    },
    {
        "anchor": "Scaling properties of SU(2) gauge theory with mixed fundamental-adjoint\n  action: We study the phase diagram of the SU(2) lattice gauge theory with\nfundamental-adjoint Wilson plaquette action. We confirm the presence of a first\norder bulk phase transition and we estimate the location of its end-point in\nthe bare parameter space. If this point is second order, the theory is one of\nthe simplest realizations of a lattice gauge theory admitting a continuum limit\nat finite bare couplings. All the relevant gauge observables are monitored in\nthe vicinity of the fixed point with very good control over finite-size\neffects. The scaling properties of the low-lying glueball spectrum are studied\nwhile approaching the end-point in a controlled manner.",
        "positive": "$B$ Spectroscopy from NRQCD with Dynamical Fermions: We present a lattice investigation, partially including the effects of\ndynamical quarks, of the heavy-light mesons using NRQCD for the heavy quark and\nthe Wilson action for the light quark. We performed an extensive calculation of\nthe spectrum employing a multi-state, multi-exponential fitting analysis which\nenabled us to extract the $2S{-}1S$ splitting as well as the $^1P_1{-}\\bar{S}$\nand hyperfine splittings. The Wilson action introduces a large systematic error\ninto the calculation, and within this uncertainty we obtain agreement with\nexperiment. We performed a comprehensive calculation of the heavy-light meson\nmass, investigating three methods and their range of validity. The agreement\nfound between these methods confirms that Lorentz invariance can be restored at\nthis order in NRQCD by a constant shift to all masses. We calculated\nspectroscopic quantities over a wide range in heavy quark mass and were able to\nperform a detailed investigation of heavy quark symmetry around the $b$ quark\nmass. In particular, we extracted the nonperturbative coefficients of terms in\nthe heavy quark expansion of the meson binding energy. We demonstrate the\nimportance of using tadpole-improved operators in such a calculation."
    },
    {
        "anchor": "Hybrid static potentials in SU(3) lattice gauge theory at small\n  quark-antiquark separations: We compute the $\\Pi_u$ and $\\Sigma_u^-$ hybrid static potentials in SU(3)\nlattice gauge theory using four different lattice spacings ranging from $a =\n0.040\\,\\text{fm}$ to $a = 0.093\\,\\text{fm}$. We provide lattice data points for\nquark-antiquark separations as small as $0.08\\, \\text{fm}$, where the\n$a$-dependent self-energy as well as lattice discretization errors at\ntree-level of perturbation theory and at leading order in $a^2$ have been\nremoved. We also investigate and exclude possibly present systematic errors\nfrom topological freezing, due to the finite spatial lattice volume and from\nglueball decays. Moreover, we provide corresponding parametrizations of the\npotentials, which can e.g. be used for Born-Oppenheimer predictions of heavy\nhybrid mesons.",
        "positive": "Mass of the B_c Meson in Three-Flavor Lattice QCD: We use lattice QCD to predict the mass of the $B_c$ meson. We use the MILC\nCollaboration's ensembles of lattice gauge fields, which have a quark sea with\ntwo flavors much lighter than a third. Our final result is\n$m_{B_c}=6304\\pm12^{+18}_{- 0} MeV$. The first error bar is a sum in quadrature\nof statistical and systematic uncertainties, and the second is an estimate of\nheavy-quark discretization effects."
    },
    {
        "anchor": "Nucleon axial charge and pion decay constant from two-flavor lattice QCD: The axial charge of the nucleon $g_A$ and the pion decay constant $f_\\pi$ are\ncomputed in two-flavor lattice QCD. The simulations are carried out on lattices\nof various volumes and lattice spacings. Results are reported for pion masses\nas low as $m_\\pi=130\\,\\mbox{MeV}$. Both quantities, $g_A$ and $f_\\pi$, suffer\nfrom large finite size effects, which to leading order ChEFT and ChPT turn out\nto be identical. By considering the naturally renormalized ratio $g_A/f_\\pi$,\nwe observe a universal behavior as a function of decreasing quark mass. From\nextrapolating the ratio to the physical point, we find $g_A^R=1.29(5)(3)$,\nusing the physical value of $f_\\pi$ as input and $r_0=0.50(1)$ to set the\nscale. In a subsequent calculation we attempt to extrapolate $g_A$ and $f_\\pi$\nseparately to the infinite volume. Both volume and quark mass dependencies of\n$g_A$ and $f_\\pi$ are found to be well decribed by ChEFT and ChPT. We find at\nthe physical point $g_A^R=1.24(4)$ and $f_\\pi^R=89.6(1.1)(1.8)\\,\\mbox{MeV}$.\nBoth sets of results are in good agreement with experiment. As a by-product we\nobtain the low-energy constant $\\bar{l}_4=4.2(1)$.",
        "positive": "Meron-Cluster Algorithms for Quantum Link Models: State-of-the-art algorithms for simulating fermions coupled to gauge fields\noften rely on integrating fermion degrees of freedom. While successful in\nsimulating QCD at zero chemical potential, at finite density these approaches\nare hindered by the sign problem. We discuss the simulation of lattice gauge\ntheories in the Hamiltonian formalism and present a generalized meron-cluster\nalgorithm for the simulation of the $U\\left(1\\right)$ Quantum Link Model for\nspin $1/2$. This enables the study of models directly relevant to current\nquantum simulators and is a promising first step toward constructing new\nefficient algorithms for more complicated gauge theories."
    },
    {
        "anchor": "A new efficient Cluster Algorithm for the Ising Model: Using D-theory we construct a new efficient cluster algorithm for the Ising\nmodel. The construction is very different from the standard Swendsen-Wang\nalgorithm and related to worm algorithms. With the new algorithm we have\nmeasured the correlation function with high precision over a surprisingly large\nnumber of orders of magnitude.",
        "positive": "FLIC-Overlap Fermions and Topology: APE smearing the links in the irrelevant operators of clover fermions\n(Fat-Link Irrelevant Clover (FLIC) fermions) provides significant improvement\nin the condition number of the Hermitian-Dirac operator and gives rise to a\nfactor of two savings in computing the overlap operator. This report\ninvestigates the effects of using a highly-improved definition of the lattice\nfield-strength tensor F_mu_nu in the fermion action, made possible through the\nuse of APE-smeared fat links in the construction of the irrelevant operators.\nSpurious double-zero crossings in the spectral flow of the Hermitian-Wilson\nDirac operator associated with lattice artifacts at the scale of the lattice\nspacing are removed with FLIC fermions composed with an O(a^4)-improved lattice\nfield strength tensor. Hence, FLIC-Overlap fermions provide an additional\nbenefit to the overlap formalism: a correct realization of topology in the\nfermion sector on the lattice."
    },
    {
        "anchor": "Screening of light mesons and charmonia at high temperature: We present lattice QCD results for the screening masses of light mesons and\ncharmonia. The lattice computations were performed with 2+1 flavors of improved\nstaggered quarks using quark masses which correspond to realistic pion and kaon\nmasses at zero temperature. For the light quark sector we have found that the\nscreening masses in the pseudo-scalar and the isovector scalar channels do not\nbecome degenerate at the chiral crossover temperature indicating an effective\nnon-restoration of the axial symmetry. Also the splitting between the vector\nand the pseudo-scalar screening masses persists even in the limit of zero\nlattice spacing and at a moderately high temperature around 420 MeV. In the\ncharmonium sector our investigation shows that the screening masses of the\npseudo-scalar and the vector charmonia are almost (within a few percent) equal\nto their zero temperature masses for temperatures less than 300 MeV. We also\npresent results for the charmonium screening masses using periodic boundary\nconditions along the temporal direction and discuss their implications.",
        "positive": "Fine Structure of the QCD String Spectrum: Using advanced lattice methods in Quantum Chromodynamics, three distinct\nscales are established in the excitation spectrum of the gluon field around a\nstatic quark-antiquark pair as the color source separation R is varied. On the\nshortest length scale, the excitations are consistent with states created by\nlocal gluon field operators arising from a multipole operator product\nexpansion. An intermediate crossover region below 2 fm is identified with a\ndramatic rearrangement of the level orderings. On the largest length scale of\n2-3 fm, the spectrum agrees with that expected for string-like excitations. The\nenergies nearly reproduce asymptotic pi/R string gaps, but exhibit a fine\nstructure, providing important clues for developing an effective bosonic string\ndescription."
    },
    {
        "anchor": "Baryon spectrum using Nf=2+1+1 ensembles of twisted mass fermions: We present results on the masses of the low-lying baryons using ten ensembles\nof gauge configurations with $N_f =2+1+1$ dynamical twisted mass fermions, at\nthree values of the lattice spacing, spanning a pion mass range from about 210\nMeV to about 430 MeV. The strange and charm quark masses are tuned to\napproximately their physical values. We examine isospin symmetry breaking\neffects on the baryon mass and the dependence on the lattice spacing. After\ntaking the continuum limit we use chiral perturbation theory to extrapolate to\nthe physical vlaue of the pion mass for all forty baryons. We provide\npredictions for the masses of doubly and triply charmed baryons that have not\nyet been measured experimentally.",
        "positive": "Lattice Calculation of Glueball Matrix Elements: Matrix elements of the form $ <0| Tr \\; g^{2}GG |G> $ are calculated using\nthe lattice QCD Monte Carlo method. Here, $|G>$ is a glueball state with\nquantum numbers $ 0^{++}$, $ 2^{++}$, $ 0^{-+}$ and $G$ is the gluon field\nstrength operator. The matrix elements are obtained from the hybrid correlation\nfunctions of the fuzzy and plaquette operators performed on the $12^{4}$ and\n$14^{4}$ lattices at $\\beta = 5.9 $ and $5.96$ respectively. These matrix\nelements are compared with those from the QCD sum rules and the tensor meson\ndominance model. They are the non-perturbative matrix elements needed in the\ncalculation of the partial widths of $J/\\Psi$ radiative decays into glueballs."
    },
    {
        "anchor": "Numerical Investigation of the Interface Tension in the\n  three-dimensional Ising Model: The interface tension in the three-dimensional Ising model in the low\ntemperature phase is investigated by means of the Monte Carlo method. Together\nwith other physically relevant quantities it is obtained from a calculation of\ntime-slice correlation functions in a cylindrical geometry. The results at\nthree different values of the temperature are compared with the predictions\nfrom a semiclassical approximation in the framework of renormalized $\\phi^4$\ntheory in three dimensions, and are in good agreement with them.",
        "positive": "A Parallel SSOR Preconditioner for Lattice QCD: A parallelizable SSOR preconditioning scheme for Krylov subspace iterative\nsolvers in lattice QCD applications involving Wilson fermions is presented. In\nactual Hybrid Monte Carlo and quark propagator calculations it helps to reduce\nthe number of iterations by a factor of 2 compared to conventional odd-even\npreconditioning. This corresponds to a gain in cpu-time of 30\\% - 70\\% over\nodd-even preconditioning."
    },
    {
        "anchor": "Higgs boson mass bounds in the presence of a very heavy fourth quark\n  generation: We study the effect of a potential fourth quark generation on the upper and\nlower Higgs boson mass bounds. This investigation is based on the numerical\nevaluation of a chirally invariant lattice Higgs-Yukawa model emulating the\nsame Higgs-fermion coupling structure as in the Higgs sector of the electroweak\nStandard Model. In particular, the considered model obeys a Ginsparg-Wilson\nversion of the underlying ${SU}(2)_L\\times {U}(1)_Y$ symmetry, being a global\nsymmetry here due to the neglection of gauge fields in this model. We present\nour results on the modification of the upper and lower Higgs boson mass bounds\ninduced by the presence of a hypothetical very heavy fourth quark doublet.\nFinally, we compare these findings to the standard scenario of three fermion\ngenerations.",
        "positive": "The Bayesian reconstruction of the in-medium heavy quark potential from\n  lattice QCD and its stability: We report recent results of a non-perturbative determination of the static\nheavy-quark potential in quenched and dynamical lattice QCD at finite\ntemperature. The real and imaginary part of this complex quantity are extracted\nfrom the spectral function of Wilson line correlators in Coulomb gauge. To\nobtain spectral information from Euclidean time numerical data, our study\nrelies on a novel Bayesian prescription that differs from the Maximum Entropy\nMethod. We perform simulations on quenched $32^3\\times N_\\tau$\n$(\\beta=7.0,\\xi=3.5)$ lattices with $N_\\tau=24,...,96$, which cover $839{\\rm\nMeV} \\geq T\\geq 210 {\\rm MeV}$. To investigate the potential in a quark-gluon\nplasma with light u,d and s quarks we utilize $N_f=2+1$ ASQTAD lattices with\n$m_l=m_s/20$ by the HotQCD collaboration, giving access to temperatures between\n$286 {\\rm MeV} \\geq T\\geq 148{\\rm MeV}$. The real part of the potential\nexhibits a clean transition from a linear, confining behavior in the hadronic\nphase to a Debye screened form above deconfinement. Interestingly its values\nlie close to the color singlet free energies in Coulomb gauge at all\ntemperatures. We estimate the imaginary part on quenched lattices and find that\nit is of the same order of magnitude as in hard-thermal loop perturbation\ntheory. From among all the systematic checks carried out in our study, we\ndiscuss explicitly the dependence of the result on the default model and the\nnumber of datapoints."
    },
    {
        "anchor": "Isoscalar $\u03c0\u03c0, K\\overline{K}, \u03b7\u03b7$ scattering and the $\u03c3,\n  f_0, f_2$ mesons from QCD: We present the first lattice QCD study of coupled isoscalar\n$\\pi\\pi,K\\overline{K},\\eta\\eta$ $S$- and $D$-wave scattering extracted from\ndiscrete finite-volume spectra computed on lattices which have a value of the\nquark mass corresponding to $m_\\pi\\sim391$ MeV. In the $J^P=0^+$ sector we find\nanalogues of the experimental $\\sigma$ and $f_0(980)$ states, where the\n$\\sigma$ appears as a stable bound-state below $\\pi\\pi$ threshold, and, similar\nto what is seen in experiment, the $f_0(980)$ manifests itself as a dip in the\n$\\pi\\pi$ cross section in the vicinity of the $K\\overline{K}$ threshold. For\n$J^P=2^+$ we find two states resembling the $f_2(1270)$ and $f_2'(1525)$,\nobserved as narrow peaks, with the lighter state dominantly decaying to\n$\\pi\\pi$ and the heavier state to $K\\overline{K}$. The presence of all these\nstates is determined rigorously by finding the pole singularity content of\nscattering amplitudes, and their couplings to decay channels are established\nusing the residues of the poles.",
        "positive": "Bulk thermodynamics and charge fluctuations at non-vanishing baryon\n  density: We present results on bulk thermodynamic quantities as well as net baryon\nnumber, strangeness and electric charge fluctuations in QCD at non-zero density\nand temperature obtained from lattice calculations with almost physical quark\nmasses for two values of the lattice cut-off $aT=1/4$ and 1/6 . We show that\nwith our improved p4fa3-action the cut-off effects are under control when using\nlattices with a temporal extent of 6 or larger and that the contribution to the\nequation of state, which is due to a finite chemical potential is small for\n$\\mu_q/T<1$. Moreover, at vanishing chemical potential, i.e. under conditions\nalmost realized at RHIC and the LHC, quartic fluctuations of net baryon number\nand strangeness are large in a narrow temperature interval characterizing the\ntransition region from the low to high temperature phase. At non-zero baryon\nnumber density, strangeness fluctuations are enhanced and correlated to\nfluctuations of the net baryon number. If strangeness is furthermore forced to\nvanish, as it may be the case in systems created in heavy ion collisions,\nstrangeness fluctuations are significantly smaller than baryon number\nfluctuations."
    },
    {
        "anchor": "Landau, Abrikosov, Hofstadter: Magnetic Flux Penetration in a Lattice\n  Superconductor: Magnetic flux penetration in superconductors involves a rich variety of\nsubtle phenomena, much of which is still poorly understood. Here these\ncomplexities are studied by formulating the Ginzburg-Landau equations as a\nlattice gauge theory. Their solutions are compared and contrasted with the\n(heuristic) Landau model of type I superconductivity, and the (perturbative)\nAbrikosov model for type II superconductors. Novelties arise as the continuum\nlimit is approached, related to an effect discovered by Hofstadter. Various\ncautionary remarks pertinent to large-scale simulations are made.",
        "positive": "Can a flavour-conserving treatment improve things ?: In this work I would like to present some ideas on how to improve on the\ngauge sector in our lattice simulations at finite baryon density. The long\nstanding problem, that we obtain an onset in thermodynamic quantities at a much\nsmaller chemical potential than expected, could be related to an unphysical\nproliferation of flavours due to hard gluons close to the Brillouin edges.\nThese hard gluons produce flavour non-conserving vertices to the fermion\nsector. They also produce excessive number of small instantons due to lattice\ndislocations. Both unphysical effects could increase the propagation in\n(di)-quarks to give the early onset in $\\mu$. Thus we will present here a\nmodified action that avoids large fields close to the lattice cutoff. Some of\nthese ideas have been tested for SU(2) and are being implemented for SU(3)."
    },
    {
        "anchor": "Scalar QED$_2$ with a topological term - a lattice study in a dual\n  representation: We present a dual representation for the partition function of 2-dimensional\nscalar quantum electrodynamics with a topological term ($\\theta$-term). In the\ndual representation the complex action problem at non-zero $\\theta$ is absent,\nwhich is an obstacle for Monte Carlo simulations in the conventional form of\nthe model. We discuss the technical aspects of the dual representation and show\nthat a dual Monte Carlo simulation can be implemented. As a first application\nwe demonstrate how the $2\\pi$-periodicity of physical observables is recovered\nin a suitable continuum limit.",
        "positive": "Quantum critical behavior in three dimensional lattice Gross-Neveu\n  models: We study quantum critical behavior in three dimensional lattice Gross-Neveu\nmodels containing two massless Dirac fermions. We focus on two models with\nSU(2) flavor symmetry and either a $Z_2$ or a U(1) chiral symmetry. Both models\ncould not be studied earlier due to sign problems. We use the fermion bag\napproach which is free of sign problems and compute critical exponents at the\nphase transitions. We estimate $\\nu = 0.83(1)$, $\\eta = 0.62(1)$, $\\eta_\\psi =\n0.38(1)$ in the $Z_2$ and $\\nu = 0.849(8)$, $\\eta = 0.633(8)$, $\\eta_\\psi =\n0.373(3)$ in the U(1) model."
    },
    {
        "anchor": "Nucleon Masses and Magnetic Moments in a Finite Volume: We compute finite-size corrections to nucleon masses and magnetic moments in\na periodic, spatial box of size L, both in QCD and in partially-quenched QCD.",
        "positive": "Numerical results of two-dimensional N=(2,2) super Yang-Mills theory: We report the results of a numerical simulation of a lattice formulation of\nthe two-dimensional N=(2,2) super Yang-Mills theory proposed by Suzuki and\nTaniguchi. We measure the 1-point functions and 2-point functions. The scenario\nis that only tuning of the scalar mass to a specific value gives a\nsupersymmetric continuum limit. Our results are consistent with this scenario\nalthough conclusive results on the restoration of supersymmetry have not been\nobtained."
    },
    {
        "anchor": "The static-light meson spectrum from twisted mass lattice QCD: We compute the static-light meson spectrum with N_f = 2 flavours of sea\nquarks using Wilson twisted mass lattice QCD. We consider five different values\nfor the light quark mass corresponding to 300 MeV < m_PS < 600 MeV and we\npresent results for angular momentum j = 1/2, j = 3/2 and j = 5/2 and for\nparity P = + and P = -. We extrapolate our results to physical quark masses and\nmake predictions regarding the spectrum of B and B_s mesons.",
        "positive": "Pad\u00e9 Approximants and the analytic structure of the gluon and ghost\n  propagators: In a Quantum Field Theory, the analytic structure of the 2-points correlation\nfunctions, ie the propagators, encloses information about the properties of the\ncorresponding quanta, particularly if they are or not confined. However, in\nQuantum Chromodynamics (QCD), we can only have an analytic solution in a\nperturbative picture of the theory. For the non-perturbative propagators, one\nresorts on numerical solutions of QCD that accesses specific regions of the\nEuclidean momentum space, as, for example, those computed via Monte Carlo\nsimulations on the lattice. In the present work, we rely on Pad\\'e Approximants\n(PA) to approximate the numerical data for the gluon and ghost propagators, and\ninvestigate their analytic structures. In a first stage, the advantages of\nusing PAs are explored when reproducing the properties of a function, focusing\non its analytic structure. The use of PA sequences is tested for the\nperturbative solutions of the propagators, and a residue analysis is performed\nto help in the identification of the analytic structure. A technique used to\napproximate a PA to a discrete set of points is proposed and tested for some\ntest data sets. Finally, the methodology is applied to the Landau gauge gluon\nand ghost propagators, obtained via lattice simulations. The results identify a\nconjugate pair of complex poles for the gluon propagator, that is associated\nwith the infrared structure of the theory. This is in line with the presence of\nsingularities for complex momenta in theories where confinement is observed.\nRegarding the ghost propagator, a pole at $p^2=0$ is identified. For both\npropagators, a branch cut is found on the real negative $p^2$-axis, which\nrecovers the perturbative analysis at high momenta."
    },
    {
        "anchor": "Propagators and Dimensional Reduction of Hot SU(2) Gauge Theory: We investigate the large distance behavior of the electric and magnetic\npropagators of hot SU(2) gauge theory in different gauges using lattice\nsimulations of the full 4d theory and the effective, dimensionally reduced 3d\ntheory. Comparison of the 3d and 4d propagators suggests that dimensional\nreduction works surprisingly well down to the temperature T=2 T_c. Within\nstatistical uncertainty the electric screening mass is found to be gauge\nindependent. The magnetic propagator, on the other hand, exhibits a complicated\ngauge dependent structure at low momentum.",
        "positive": "Running coupling constant and correlation length from Wilson loops: We consider a definition of the QCD running coupling constant $\\alpha(\\mu)$\nrelated to Wilson loops of size $r{\\times}t$ with arbitrary fixed $t/r$. The\nschemes defined by these couplings are very close to the $\\overline{\\rm MS}$\nscheme (i.e.\\ the one-loop perturbative correction to the coupling is small)\nfor all values of $t/r$; in the $t/r\\to\\infty$ limit, the ``$q\\bar q$ force''\nscheme is recovered, where the coupling constant is related to the\nquark-antiquark force. We discuss the possibility of applying finite-size\nscaling techniques to the Monte Carlo evaluation of $\\alpha(\\mu)$ up to very\nlarge momentum scales. We propose a definition of correlation length, also\nrelated to Wilson loops, which should make such a computation feasible."
    },
    {
        "anchor": "Evidence that centre vortices underpin dynamical chiral symmetry\n  breaking in $\\mathrm{SU}(3)$ gauge theory: The link between dynamical chiral symmetry breaking and centre vortices in\nthe gauge fields of pure $\\mathrm{SU}(3)$ gauge theory is studied using the\noverlap-fermion quark propagator in Lattice QCD. Overlap fermions provide a\nlattice realisation of chiral symmetry and consequently offer a unique\nopportunity to explore the interplay of centre vortices, instantons and\ndynamical mass generation. Simulations are performed on gauge fields featuring\nthe removal of centre vortices, identified through gauge transformations\nmaximising the center of the gauge group. In contrast to previous results using\nthe staggered-fermion action, the overlap-fermion results illustrate a loss of\ndynamical chiral symmetry breaking coincident with vortex removal. This result\nis linked to the overlap-fermion's sensitivity to the subtle manner in which\ninstanton degrees of freedom are compromised through the process of centre\nvortex removal. Backgrounds consisting solely of the identified centre vortices\nare also investigated. After smoothing the vortex-only gauge fields, we observe\ndynamical mass generation on the vortex-only backgrounds consistent within\nerrors with the original gauge-field ensemble following the same smoothing.\nThrough visualizations of the instanton-like degrees of freedom in the various\ngauge-field ensembles, we find evidence of a link between the centre vortex and\ninstanton structure of the vacuum. While vortex removal destabilizes\ninstanton-like objects under ${\\cal\n  O}(a^4)$-improved cooling, vortex-only backgrounds provide gauge-field\ndegrees of freedom sufficient to create instantons upon cooling.",
        "positive": "Perturbative Renormalization of Wilson line operators: We present results for the renormalization of gauge invariant nonlocal\nfermion operators which contain a Wilson line, to one loop level in lattice\nperturbation theory. Our calculations have been performed for Wilson/clover\nfermions and a wide class of Symanzik improved gluon actions. The extended\nnature of such `long-link' operators results in a nontrivial renormalization,\nincluding contributions which diverge linearly as well as logarithmically with\nthe lattice spacing, along with additional finite factors. We present\nnonperturbative prescriptions to extract the linearly divergent contributions."
    },
    {
        "anchor": "Sextet QCD: slow running and the mass anomalous dimension: I report the results of Schroedinger functional calculations in the SU(3)\ngauge theory with two flavors of color sextet fermions, defined with the\nWilson-clover action using nHYP fat links. While we cannot confirm the infrared\nfixed point seen with thin links, we find very slow evolution of the coupling\nconstant, so slow that extraction of the mass anomalous dimension is\nstraightforward.",
        "positive": "The Weak-Coupling Limit of Simplicial Quantum Gravity: In the weak-coupling limit, kappa_0 going to infinity, the partition function\nof simplicial quantum gravity is dominated by an ensemble of triangulations\nwith the ratio N_0/N_D close to the upper kinematic limit. For a combinatorial\ntriangulation of the D--sphere this limit is 1/D. Defining an ensemble of\nmaximal triangulations, i.e. triangulations that have the maximal possible\nnumber of vertices for a given volume, we investigate the properties of this\nensemble in three dimensions using both Monte Carlo simulations and a\nstrong-coupling expansion of the partition function, both for pure simplicial\ngravity and a with a suitable modified measure. For the latter we observe a\ncontinuous phase transition to a crinkled phase and we investigate the fractal\nproperties of this phase."
    },
    {
        "anchor": "Complex spectrum of spin models for finite-density QCD: We consider the spectrum of transfer matrix eigenvalues associated with\nPolyakov loops in lattice QCD at strong coupling. The transfer matrix at finite\ndensity is non-Hermitian, and its eigenvalues become complex as a manifestation\nof the sign problem. We show that the symmetry under charge conjugation and\ncomplex conjugation ensures that the eigenvalues are either real or part of a\ncomplex conjugate pair, and the complex pairs lead to damped oscillatory\nbehavior in Polyakov loop correlation functions, which also appeared in our\nprevious phenomenological models using complex saddle points. We argue that\nthis effect should be observable in lattice simulations of QCD at finite\ndensity.",
        "positive": "Disconnected quark loop contributions to nucleon observables using\n  $N_f=2$ twisted clover fermions at the physical value of the light quark mass: We compute the disconnected quark loops contributions entering the\ndetermination of nucleon observables, by using a $N_f = 2$ ensemble of twisted\nmass fermions with a clover term at a pion mass $m_\\pi = 133$ MeV. We employ\nexact deflation and implement all calculations in GPUs, enabling us to achieve\nlarge statistics and a good signal."
    },
    {
        "anchor": "Mass spectrum of 1-+ exotic mesons from lattice QCD: Time correlation functions of a hybrid exotic meson operator, with JPC=1-+,\ngenerated in quenched lattice QCD are subjected to a (Bayesian) maximum entropy\nanalysis. Five distinct spectral levels are uncovered. Their extrapolation into\nthe physical pion mass region suggests a possible relationship to\nexperimentally known states pi1(1400) and pi1(1600), and also to a state in the\n2 GeV region carrying the same quantum numbers.",
        "positive": "Chiral Logs in the Presence of Staggered Flavor Symmetry Breaking: Chiral logarithms in $m_\\pi^2$ are calculated at one loop, taking into\naccount the leading contributions to flavor symmetry breaking due to staggered\nfermions. I treat both the full QCD case (2+1 light dynamical flavors) and the\nquenched case; finite volume corrections are included. My starting point is the\neffective chiral Lagrangian introduced by Lee and Sharpe. It is necessary to\nunderstand the one-loop diagrams in the ``quark flow'' picture in order to\nadjust the calculation to correspond to the desired number of dynamical quarks."
    },
    {
        "anchor": "Pseudoscalar decay constants, light-quark masses, and B_K from\n  mixed-action lattice QCD: We present updated results for the leptonic decay constants f_pi and f_K, the\nlight u, d, and s-quark masses, and the neutral kaon mixing parameter B_K from\nmixed-action lattice simulations with staggered sea quarks and domain-wall\nvalence quarks. We use the publicly-available 2+1 flavor MILC asqtad-improved\nstaggered gauge configurations with multiple light sea-quark masses and three\nlattice spacings, and compute the kaon mixing matrix element with several\npartially-quenched valence-quark masses. We then extrapolate to the physical\nlight-quark masses and the continuum using partially-quenched chiral\nperturbation theory formulated for mixed-action lattice simulations. For B_K we\nmatch the lattice four-fermion operator to the continuum using the\nnonperturbative method of Rome-Southampton. Our new results benefit from two\nsignificant improvements over our published work: (1) we have added a third\nlattice spacing of a~0.06 fm to better control the continuum extrapolation, and\n(2) we have implemented a new lattice renormalization scheme (the\nRI/SMOM_{gamma_mu} scheme developed by Sturm et al.) that suppresses\nchiral-symmetry breaking and other infrared effects and, in practice, also\nshrinks the size of the 1-loop perturbative coefficient needed to match to the\ncontinuum MS-bar scheme. When combined with the use of volume-averaged momentum\nsources and twisted-boundary conditions, this significantly reduces the\nsystematic uncertainty in the renormalization factor Z_{B_K}.",
        "positive": "Phase structure of lattice QCD with Wilson and Neuberger quarks at\n  finite temperature and density: We review our results for lattice QCD at finite temperature and density from\nanalytical and numerical calculations with Wilson fermions and overlap\nfermions."
    },
    {
        "anchor": "Finite-Size analysis of the 4-d abelian surface gauge model: We present the results of a finite-size analysis of the four dimensional\nabelian surface gauge model. This model is defined assigning abelian variables\nto the plaquettes of an hypercubical lattice, and is dual to the four\ndimensional Ising model. This last model is known to present a second order\nphase transition with mean field critical exponents. We have performed Monte\nCarlo simulations on several lattice sizes and high statistics. The analysis of\nthe partition function zeroes and the specific heat scaling behaviour allowed\nus to estimate the critical coupling $\\beta_c$ as well as the critical\nexponents $\\nu$ and $\\alpha$. Our results are consistent with the second order\ncritical exponents $\\nu = 1/2$ and $\\alpha = 0$. The $\\beta_c$ value is in\nperfect agreement with duality predictions from the 4-d Ising model.\nNevertheless, the energy histograms show a seemingly non-vanishing double peak\nstructure. The interface tension analysis suggests that this may be a finite\nsize effect.",
        "positive": "Finite size scaling on the phase diagram of QCD: In the last years there has been remarkable progress in the comparison of\nexperimental data on the shape of event-by-event distributions of conserved\nquantities and lattice thermodynamic predictions based on the grand canonical\nensemble. In this talk we discuss how the QCD crossover temperature and the\nfreezeout curve are extracted from the analysis of fluctuations. We report that\none can also go further and locate the QCD critical point already from\npublished data. We also list the systematics which must be brought under\ncontrol in future."
    },
    {
        "anchor": "Gauge-invariant nonlocal quark condensates in QCD: We study, by numerical simulations on a lattice, the behaviour of the\ngauge-invariant nonlocal quark condensates in the QCD vacuum both in the\nquenched approximation and with four flavours of dynamical staggered fermions.\nThe correlation length of the condensate is determined to be roughly twice as\nbig as in the case of the gluon field strength correlators.",
        "positive": "Reweighting Lefschetz Thimbles: We present a novel reweighting technique to calculate the relative weights in\nthe Lefschetz thimble decomposition of a path integral. Our method is put to\nwork using a $U(1)$ one-link model providing for a suitable testing ground and\nsharing many features with realistic gauge theories with fermions at finite\ndensity. We discuss prospects and future challenges to our method."
    },
    {
        "anchor": "apenext: A Multi-Tflops LQCD Computing Project: This paper is a slightly modified and reduced version of the proposal of the\n{\\bf apeNEXT} project, which was submitted to DESY and INFN in spring 2000. .It\npresents the basic motivations and ideas of a next generation lattice QCD\n(LQCD) computing project, whose goal is the construction and operation of\nseveral large scale Multi-TFlops LQCD engines, providing an integrated peak\nperformance of tens of TFlops, and a sustained (double precision) performance\non key LQCD kernels of about 50% of peak speed.",
        "positive": "Second moment of the pion's distribution amplitude: We present preliminary results from the QCDSF/UKQCD collaborations for the\nsecond moment of the pion's distribution amplitude with two flavours of\ndynamical fermions. We use nonperturbatively determined renormalisation\ncoefficients to convert our results to the MSbar scheme at 5 GeV^2. Employing a\nlinear chiral extrapolation from our large pion masses >550 MeV, we find\n<xi^2>=0.281(28), leading to a value of a_2=0.236(82) for the second Gegenbauer\nmoment."
    },
    {
        "anchor": "More on String Breaking in the 3D Abelian Higgs Model: the Photon\n  Propagator: We study the Landau gauge photon propagator in the three--dimensional Abelian\nHiggs model with compact gauge field and fundamentally charged matter in the\nLondon limit. The total gauge field is split into singular and regular parts.\nOn the confinement side of the string breaking crossover the momentum\ndependence of the total propagator is characterized by an anomalous dimension\nsimilarly to 3D compact QED. At the crossover and throughout the Higgs region\nthe anomalous dimension disappears. This result perfectly agrees with recent\nobservations that the monopole--antimonopole plasma leads to nonzero anomalous\ndimension and the presence of the matter fields causes monopole pairing into\ndipole bound states. The Yukawa mass characterizing the propagator part from\nregular gauge fields is non-vanishing at the Higgs side and coincides with the\nmass found for the total propagator. The regular gauge field without anomalous\ndimension becomes massless at the crossover and in the confinement region.",
        "positive": "B_s meson excited states from the lattice: This is a follow-up to our earlier work [Phys. Rev. D 65, 014512 (2002); Eur.\nPhys. J. C 28, 79 (2003); Phys. Rev. D 69, 094505 (2004)] for the energies and\nthe charge (vector) and matter (scalar) distributions for S-wave states in a\nheavy-light meson, where the heavy quark is static and the light quark has a\nmass about that of the strange quark. We study the radial distributions of\nhigher angular momentum states, namely P- and D-wave states. In nature the\nclosest equivalent of this heavy-light system is the B_s meson.\n  The calculation is carried out with dynamical fermions on a 16^3 times 32\nlattice with a lattice spacing of about 0.10 fm generated with the\nnon-perturbatively improved clover action. It is shown that several features of\nthe energies and radial distributions are in qualitative agreement with what\none expects from a simple one-body Dirac equation interpretation."
    },
    {
        "anchor": "Bound states for Overlap and Fixed Point Actions close to the chiral\n  limit: We study the overlap and the fixed point Dirac operators for massive fermions\nin the two-flavor lattice Schwinger model. The masses of the triplet (pion) and\nsinglet (eta) bound states are determined down to small fermion masses and the\nmass dependence is compared with various continuum model approximations. Near\nthe chiral limit, at very small fermion masses the fixed point operator has\nstability problems, which in this study are dominated by finite size effects,",
        "positive": "SU(3) Latent Heat and Surface Tension from Tree Level and Tadpole\n  Improved Actions: We analyze the latent heat and surface tension at the SU(3) deconfinement\nphase transition with tree level and tadpole improved Symanzik actions on\nlattices with temporal extent $N_\\tau = 3$ and 4 and spatial extent $N_\\sigma/\nN_\\tau = 4$, 6 and 8. In comparison to the standard Wilson action we do find a\ndrastic reduction of cut-off effects already with tree level improved actions.\nOn lattices with temporal extent $N_\\tau=4$ results for the surface tension and\nlatent heat obtained with a tree level improved action agree well with those\nobtained with a tadpole improved action. A comparison with $N_\\tau=3$\ncalculations, however, shows that results obtained with tadpole action remain\nunaffected by cut-off effects even on this coarse lattice, while the tree level\naction becomes sensitive to the cut-off. For the surface tension and latent\nheat we find $\\sigma_I/ T_c^3 = 0.0155~(16)$ and $\\Delta\\epsilon/T_c^4 =\n1.40~(9)$, respectively."
    },
    {
        "anchor": "Hadronic vacuum polarization in finite volume using NNLO ChPT: We present results for the leading hadronic contribution to the muon $g-2$\nfrom configurations with 2+1+1 flavors of HISQ quarks. The ensembles have been\ngenerated by the MILC collaboration at three lattice spacings. Using the\ntime-momentum representation of the electromagnetic current correlator, we\ncalculate the finite volume effects up to next-to-next-to-leading-order in\nChiral Perturbation Theory.",
        "positive": "Restoration of chiral symmetry in cold and dense Nambu--Jona-Lasinio\n  model with tensor renormalization group: We analyze the chiral phase transition of the Nambu--Jona-Lasinio model in\nthe cold and dense region on the lattice developing the Grassmann version of\nthe anisotropic tensor renormalization group algorithm. The model is formulated\nwith the Kogut--Susskind fermion action. We use the chiral condensate as an\norder parameter to investigate the restoration of the chiral symmetry. The\nfirst-order chiral phase transition is clearly observed in the dense region at\nvanishing temperature with $\\mu/T\\sim O(10^3)$ on a large volume of $V=1024^4$.\nWe also present the results for the equation of state."
    },
    {
        "anchor": "$D \\rightarrow \u03c0, l \u03bd$ Semileptonic Decays, $|V_{cd}|$ and 2$^{nd}$\n  Row Unitarity from Lattice QCD: We present a new calculation of the $D \\rightarrow \\pi, l \\nu$ semileptonic\nform factor $f^{D \\rightarrow \\pi}_+(q^2)$ at $q^2 = 0$ based on HISQ charm and\nlight valence quarks on MILC $N_f = 2 +1$ lattices. Using methods developed\nrecently for HPQCD's study of $D \\rightarrow K, l \\nu$ decays, we find $f^{D\n\\rightarrow \\pi}_+(0) = 0.666(29)$. This signifies a better than factor of two\nimprovement in errors for this quantity compared to previous calculations.\nCombining the new result with CLEO-c branching fraction data, we extract the\nCKM matrix element $|V_{cd}| = 0.225(6)_{exp.}(10)_{lat.}$, where the first\nerror comes from experiment and the second from theory. With a total error of\n$\\sim5.3$\\% the accuracy of direct determination of $|V_{cd}|$ from $D$\nsemileptonic decays has become comparable to (and in good agreement with) that\nfrom neutrino scattering. We also check for second row unitarity using this new\n$|V_{cd}|$, HPQCD's earlier $|V_{cs}|$ and $|V_{cb}|$ from the Fermilab Lattice\n\\& MILC collaborations. We find $|V_{cd}|^2 + |V_{cs}|^2 + |V_{cb}|^2 =\n0.976(50)$, improving on the current PDG2010 value.",
        "positive": "Reply to Comment on ``Asymptotic Scaling in the Two-Dimensional O(3)\n  sigma-Model at Correlation Length 10^5\": We reply to criticism by Patrascioiu and Seiler [hep-lat/9502019] of our\nresults [Phys. Rev. Lett. 75, 1891 (1995), hep-lat/9411009] on asymptotic\nscaling in the two-dimensional $O(3)$ $\\sigma$-model, which were based on a\nfinite-size-scaling extrapolation method."
    },
    {
        "anchor": "Ising and Potts Models on Quenched Random Gravity Graphs: We report on single-cluster Monte Carlo simulations of the Ising, 4-state\nPotts and 10-state Potts models on quenched ensembles of planar, tri-valent\nrandom graphs. We confirm that the first-order phase transition of the 10-state\nPotts model on regular 2D lattices is softened by the quenched connectivity\ndisorder represented by the random graphs and that the exponents of the Ising\nand 4-state Potts models are altered from their regular lattice counterparts.\nThe behaviour of spin models on such graphs is thus more analogous to models\nwith quenched bond disorder than to Poisonnian random lattices, where regular\nlattice critical behaviour persists.\n  Using a wide variety of estimators we measure the critical exponents for all\nthree models, and compare the exponents with predictions derived from taking a\nquenched limit in the KPZ formula for the Ising and 4-state Potts models.\nEarlier simulations suggested that the measured values for the 10-state Potts\nmodel were very close to the predicted quenched exponents of the {\\it\nfour}-state Potts models. The analysis here, which employs a much greater range\nof estimators and also benefits from greatly improved statistics, still\nsupports these numerical values.",
        "positive": "Position space formulation for Dirac fermions on honeycomb lattice: We study how to construct Dirac fermion defined on the honeycomb lattice in\nposition space. Starting from the nearest neighbor interaction in tight binding\nmodel, we show that the Hamiltonian is constructed by kinetic term and second\nderivative term of three flavor Dirac fermions in which one flavor has a mass\nof cutoff order and the other flavors are massless. In this formulation the\nstructure of the Dirac point is simplified so that its uniqueness can be easily\nshown even if we consider the next-nearest neighbor interaction. We also show\nthe chiral symmetry at finite lattice spacing, which protects the masslessness\nof the Dirac fermion, and discuss the analogy with the staggered fermion\nformulation."
    },
    {
        "anchor": "Hadron Structure from Lattice QCD: Recent progress in lattice QCD calculations of nucleon structure will be\npresented. Calculations of nucleon matrix elements and form factors have long\nbeen difficult to reconcile with experiment, but with advances in both\nmethodology and computing resources, this situation is improving. Some\ncalculations have produced agreement with experiment for key observables such\nas the axial charge and electromagnetic form factors, and the improved\nunderstanding of systematic errors will help to increase confidence in\npredictions of unmeasured quantities. The long-omitted disconnected\ncontributions are now seeing considerable attention and some recent\ncalculations of them will be discussed.",
        "positive": "Numerical Evaluation of a Soliton Pair with Long Range Interaction: Within the model of topological particles (MTP) we determine the interaction\nenergy of monopole pairs, sources and sinks of a Coulombic field. The monopoles\nare represented by topological solitons of finite size and mass, described by a\nfield without any divergences. We fix the soliton centres in numerical\ncalculations at varying distance. Due to the finite size of the solitons we get\ndeviations from the Coulomb potential at distances of a few soliton radii. We\ncompare the numerical results for these deviations with the running of the\ncoupling in perturbative QED."
    },
    {
        "anchor": "Lattice implementation of Abelian gauge theories with Chern-Simons\n  number and an axion field: Real time evolution of classical gauge fields is relevant for a number of\napplications in particle physics and cosmology, ranging from the early Universe\nto dynamics of quark-gluon plasma. We present a lattice formulation of the\ninteraction between a $shift$-symmetric field and some $U(1)$ gauge sector,\n$a(x)\\tilde{F}_{\\mu\\nu}F^{\\mu\\nu}$, reproducing the continuum limit to order\n$\\mathcal{O}(dx_\\mu^2)$ and obeying the following properties: (i) the system is\ngauge invariant and (ii) shift symmetry is exact on the lattice. For this end\nwe construct a definition of the {\\it topological number density} $Q =\n\\tilde{F}_{\\mu\\nu}F^{\\mu\\nu}$ that admits a lattice total derivative\nrepresentation $Q = \\Delta_\\mu^+ K^\\mu$, reproducing to order\n$\\mathcal{O}(dx_\\mu^2)$ the continuum expression $Q = \\partial_\\mu K^\\mu\n\\propto \\vec E \\cdot \\vec B$. If we consider a homogeneous field $a(x) = a(t)$,\nthe system can be mapped into an Abelian gauge theory with Hamiltonian\ncontaining a Chern-Simons term for the gauge fields. This allow us to study in\nan accompanying paper the real time dynamics of fermion number non-conservation\n(or chirality breaking) in Abelian gauge theories at finite temperature. When\n$a(x) = a(\\vec x,t)$ is inhomogeneous, the set of lattice equations of motion\ndo not admit however a simple explicit local solution (while preserving an\n$\\mathcal{O}(dx_\\mu^2)$ accuracy). We discuss an iterative scheme allowing to\novercome this difficulty.",
        "positive": "Non-perturbative running of the average momentum of non-singlet parton\n  densities: We determine non-perturbatively the anomalous dimensions of the second moment\nof non-singlet parton densities from a continuum extrapolation of results\ncomputed in quenched lattice simulations at different lattice spacings. We use\na Schr\\\"odinger functional scheme for the definition of the renormalization\nconstant of the relevant twist-2 operator. In the region of renormalized\ncouplings explored, we obtain a good description of our data in terms of a\nthree-loop expression for the anomalous dimensions. The calculation can be used\nfor exploring values of the coupling where a perturbative expansion of the\nanomalous dimensions is not valid a priori. Moreover, our results provide the\nnon-perturbative renormalization constant that connects hadron matrix elements\non the lattice, renormalized at a low scale, with the experimental results,\nrenormalized at much higher energy scales."
    },
    {
        "anchor": "Electroweak phase transition by four dimensional simulations: The finite temperature phase transition in the SU(2)-Higgs model at a Higgs\nboson mass $M_H \\simeq 35$ GeV is studied in numerical simulations on four\ndimensional lattices with time-like extensions up to $L_t=5$. $T_c/M_H$ is\nextrapolated to the continuum limit and a comparison with the perturbative\nprediction is made. A one-loop calculation to the coupling anisotropies of the\nSU(2)-Higgs model on lattices with asymmetric lattice spacings is presented.\nOur numerical simulations show that the above perturbative result is applicable\nin the phenomenologically interesting parameter region.",
        "positive": "Flux tubes in the QCD vacuum: The hypothesis that the QCD vacuum can be modeled as a dual superconductor is\na powerful tool to describe the distribution of the color field generated by a\nquark-antiquark static pair and, as such, can provide useful clues for the\nunderstanding of confinement. In this work we investigate, by lattice Monte\nCarlo simulations of the $SU(3)$ pure gauge theory and of (2+1)-flavor QCD with\nphysical mass settings, some properties of the chromoelectric flux tube at zero\ntemperature and their dependence on the physical distance between the static\nsources. We draw some conclusions about the validity domain of the dual\nsuperconductor picture."
    },
    {
        "anchor": "Light Quark Masses with Dynamical Wilson Fermions: We determine the masses of the light and the strange quarks in the\n$\\bar{MS}$-scheme using our high-statistics lattice simulation of QCD with\ndynamical Wilson fermions. For the light quark mass we find\n$m^{light}_{\\bar{MS}}(2 GeV) = 2.7(2) MeV$, which is lower than in quenched\nsimulations. For the strange quark, in a sea of two dynamical light quarks, we\nobtain $m^{strange}_{\\bar{MS}}(2 GeV) = 140(20) MeV$.",
        "positive": "Complex Langevin calculations in finite density QCD at large $\u03bc/T$\n  with the deformation technique: It is well known that investigating QCD at finite density by standard Monte\nCarlo methods is extremely difficult due to the sign problem. Some years ago,\nthe complex Langevin method with gauge cooling was shown to work at high\ntemperature, i.e., in the deconfined phase. The same method was also applied to\nQCD in the so-called heavy dense limit in the whole temperature region. In this\npaper we attempt to apply this method to the large $\\mu/T$ regime with moderate\nquark mass using four-flavor staggered fermions on a $4^3\\times 8$ lattice.\nWhile a straightforward application faces with the singular-drift problem,\nwhich spoils the validity of the method, we overcome this problem by the\ndeformation technique proposed earlier. Explicit results for the quark number\ndensity and the chiral condensate obtained in this way for $3.2\\leq \\mu/T\\leq\n5.6$ are compared with the results for the phase-quenched model obtained by the\nstandard rational hybrid Monte Carlo calculation. This reveals a clear\ndifference, which is qualitatively consistent with the Silver Blaze phenomenon."
    },
    {
        "anchor": "Composite reweighting SU(2) QCD at Finite Temperature: The Glasgow reweighting method is evaluated for SU(2) lattice gauge theory at\nnonzero \\mu and finite T. We establish that the ' overlap problem' of SU(3)\nmeasurements, in which the transition points determined from thermodynamic\nobservables have an unphysical dependence on the value of \\mu used in the\nreweighting persists for SU(2). By combining the information from different\nlattice ensembles we alleviate sampling bias in the fugacity expansion, and\nidentify the Lee-Yang zeros associated with the transition to a high density\nphase that can plausibly be associated with diquark condensation. We also\nconfirm the existence of a line of first order transitions above a critical\npoint in the T-\\mu plane previously identified by effective chiral lagrangian\ncalculations.",
        "positive": "Heavy Quark Spectroscopy and Matrix Elements: A Lattice Study using the\n  Static Approximation: We present results of a lattice analysis of the $B$ parameter, $B_B$, the\ndecay constant $f_B$, and several mass splittings using the static\napproximation. Results were obtained for 60 quenched gauge configurations\ncomputed at $\\beta=6.2$ on a lattice size of $24^3\\times48$. Light quark\npropagators were calculated using the $O(a)$-improved Sheikholeslami-Wohlert\naction. We find $\\Bbstat(m_b) = 0.69\\er{3}{4} {\\rm(stat)}\\er{2}{1}\n{\\rm(syst)}$, corresponding to $\\Bbstat = 1.02\\er{5}{6}\\er{3}{2}$, and $\\fbstat\n= 266\\err{18}{20}\\err{28}{27} \\mev$, $f_{B_s}^2 B_{B_s}/f_B^2 B_B =\n1.34\\er{9}{8}\\er{5}{3}$, where a variational fitting technique was used to\nextract $\\fbstat$. For the mass splittings we obtain $M_{B_s}-M_{B_d} =\n87\\err{15}{12}\\err{6}{12} \\mev$, $M_{\\Lambda_b}-M_{B_d} =\n420\\errr{100}{90}\\err{30}{30} \\mev$ and $M_{B^*}^2-M_B^2 =\n0.281\\err{15}{16}\\err{40}{37} \\gev^2$. We compare different smearing techniques\nintended to improve the signal/noise ratio. From a detailed assessment of\nsystematic effects we conclude that the main systematic uncertainties are\nassociated with the renormalisation constants relating a lattice matrix element\nto its continuum counterpart. The dependence of our findings on lattice\nartefacts is to be investigated in the future."
    },
    {
        "anchor": "Transversity parton distribution functions from lattice QCD: We present the first direct calculation of the transversity parton\ndistribution function within the nucleon from lattice QCD. The calculation is\nperformed using simulations with the light quark mass fixed to its physical\nvalue and at one value of the lattice spacing. Novel elements of the\ncalculations are non-perturbative renormalization and extraction of a formula\nfor the matching to light-cone PDFs. Final results are presented in the\n$\\overline{\\rm MS}$ scheme at a scale of $\\sqrt{2}$ GeV.",
        "positive": "Field Theory Simulations on a Fuzzy Sphere - an Alternative to the\n  Lattice: We explore a new way to simulate quantum field theory, without introducing a\nspatial lattice. As a pilot study we apply this method to the 3d \\lambda \\phi^4\nmodel. The regularisation consists of a fuzzy sphere with radius R for the two\nspatial directions, plus a discrete Euclidean time. The fuzzy sphere\napproximates the algebra of functions of the sphere with a matrix algebra, and\nthe scalar field is represented by a Hermitian N x N matrix at each time site.\nWe evaluate the phase diagram, where we find a disordered phase and an ordered\nregime, which splits into phases of uniform and non-uniform order. We discuss\nthe behaviour of the model in different limits of large N and R, which lead to\na commutative or to a non-commutative \\lambda \\phi^4 model in flat space."
    },
    {
        "anchor": "Perturbation calculation of the axial anomaly of Ginsparg-Wilson fermion: We evaluate the axial anomaly for the general Ginsparg-Wilson fermion\noperator $D = D_c (\\Id + R D_c)^{-1}$ with $R = r \\Id$. For any chirally\nsymmetric $D_c$ which in the free fermion limit, is free of species doubling\nand behaves like $i \\gamma_\\mu p_\\mu$ as $p \\to 0$, the axial anomaly\n$\\tr[\\gamma_5 (R D) (x,x)]$ for U(1) lattice gauge theory with single fermion\nflavor is equal to $e^2/(32 \\pi^2) \\epsilon_{\\mu\\nu\\lambda\\sigma} F_{\\mu\\nu}(x)\nF_{\\lambda\\sigma}(x+\\hat\\mu+\\hat\\nu)$ plus terms which are higher orders and/or\nnon-perturbative contribtuons. The $F \\tilde{F}$ term is r-invariant and has\nthe correct continuum limit.",
        "positive": "The Numerical Estimation of the Error Induced by the Valence\n  Approximation: We describe a systematic expansion for full QCD. The leading term in the\nexpansion gives the valence approximation. The expansion reproduces full QCD if\nan infinite number of higher terms are included."
    },
    {
        "anchor": "Decays rates for S- and P-wave bottomonium: We use the Bodwin-Braaten-Lepage factorization scheme to separate the long-\nand short-distance factors that contribute to the decay rates of $\\Upsilon$,\n$\\eta_b$ (S-wave) and $\\chi_b$,$h_b$ (P-wave). The long distance matrix\nelements are calculated on the lattice in the quenched approximation using a\nnon-relativistic formulation of the $b$ quark dynamics.",
        "positive": "Efficient computations of continuous action densities of states for\n  lattice models: The Logarithmic Linear Relaxation (LLR) algorithm is an efficient method for\ncomputing densities of states for systems with a continuous spectrum. A key\nfeature of this method is exponential error reduction, which allows us to\nevaluate the density of states of a system over hundreds of thousands of orders\nof magnitude with a fixed level of relative accuracy. As a consequence of\nexponential error reduction, the LLR method provides a robust alternative to\ntraditional Monte Carlo calculations in cases in which states suppressed by the\nBoltzmann weight play nevertheless a relevant role, e.g., as transition regions\nbetween dominant configuration sets. After reviewing the algorithm, we will\nshow an application in U(1) Lattice Gauge Theory that has enabled us to obtain\nthe most accurate estimate of the critical coupling with modest computational\nresources, defeating exponential tunneling times between metastable vacua. As a\nfurther showcase, we will then present an application of the LLR method to the\ndecorrelation of the topological charge in SU(3) Lattice Gauge Theory near the\ncontinuum limit. Finally, we will review in general applications of the LLR\nalgorithm to systems affected by a strong sign problem and discuss the case of\nthe Bose gas at finite chemical potential."
    },
    {
        "anchor": "Unquenching Effects on the Coefficients of the L\u00fcscher-Weisz Action: The effects of unquenching on the perturbative improvement coefficients in\nthe Symanzik action are computed within the framework of L\\\"uscher-Weisz\non-shell improvement. We find that the effects of quark loops are surprisingly\nlarge, and their omission may well explain the scaling violations observed in\nsome unquenched studies.",
        "positive": "D_s meson spectroscopy: Preliminary results are presented for the spectrum of D_s mesons using the\n2+1 flavor Clover-Wilson configurations made available by the PACS-CS\ncollaboration. For the heavy quark, the Fermilab method is employed and we\nreport on the tuning of the charm-quark hopping parameter. As our main focus,\nwe present initial results for the spectrum of P-wave states, where previous\nresults have been mostly from quenched calculations. As a cross-check, some\ncalculations of the charmonium spectrum are also carried out."
    },
    {
        "anchor": "Lanczos Methods for UV-Suppressed Fermions: In this talk I indroduce lattice fermions with suppressed cutoff modes. Then\nI present Lanczos based methods for stochastic evaluation of the fermion\ndeterminant.",
        "positive": "Multichannel one-to-two transition amplitudes in a finite volume: We perform a model-independent, non-perturbative investigation of two-point\nand three-point finite-volume correlation functions in the energy regime where\ntwo-particle states can go on-shell. We study three-point functions involving a\nsingle incoming particle and an outgoing two-particle state, relevant, for\nexample, for studies of meson decays (e.g., B-to-pi Kll) or meson photo\nproduction (e.g., pi gamma-to-pi pi). We observe that, while the spectrum\nsolely depends on the on-shell scattering amplitude, the correlation functions\nalso depend on off-shell amplitudes. The main result of this work is a\ngeneralization of the Lellouch-Luscher formula relating matrix elements of\ncurrents in finite and infinite spatial volumes. We extend that work by\nconsidering a theory with multiple, strongly-coupled channels and by\naccommodating external currents which inject arbitrary four-momentum as well as\narbitrary angular momentum. The result is exact up to exponentially suppressed\ncorrections governed by the pion mass times the box size. We also apply our\nmaster equation to various examples, including the two processes mentioned\nabove as well as examples where the final state is an admixture of two open\nchannels."
    },
    {
        "anchor": "The fate of chiral symmetries in the quark-gluon plasma: We propose a new way of understanding how chiral symmetry is realized in the\nhigh temperature phase of QCD. Based on the finding that a simple free\ninstanton gas precisely describes the details of the lowest part of the\nspectrum of the lattice overlap Dirac operator, we propose an instanton-based\nrandom matrix model of QCD with dynamical quarks. Simulations of this model\nreveal that even for small quark mass the Dirac spectral density has a\nsingularity at the origin, caused by a dilute gas of free instantons. Even\nthough the interaction, mediated by light dynamical quarks creates small\ninstanton-antiinstanton molecules, those do not influence the singular part of\nthe spectrum, and this singular part is shown to dominate Banks-Casher type\nsums in the chiral limit. By generalizing the Banks-Casher formula for the\nsingular spectrum, we show that in the chiral limit the chiral condensate\nvanishes if there are at least two massless flavors. We also resolve a\nlong-standing debate, by demonstrating that for two massless quark flavors the\n$U(1)\\msub{A}$ symmetry remains broken up to arbitrarily high finite\ntemperatures.",
        "positive": "$B\\to D^\\ast\\ell\u03bd$ at non-zero recoil: We present preliminary blinded results from our analysis of the form factors\nfor $B\\rightarrow D^\\ast\\ell\\nu$ decay at non-zero recoil. Our analysis\nincludes 15 MILC asqtad ensembles with $N_f=2+1$ flavors of sea quarks and\nlattice spacings ranging from $a\\approx 0.15$ fm down to $0.045$ fm. The\nvalence light quarks employ the asqtad action, whereas the $b$ and $c$ quarks\nare treated using the Fermilab action. We discuss the impact that our results\nwill have on $\\left|V_{cb}\\right|$ and $R(D^\\ast)$."
    },
    {
        "anchor": "On curing the divergences in the quark number susceptibility: Adding chemical potential $\\mu$ linearly as $\\mu N$ to the lattice QCD\naction, where $N$ is a conserved quark/baryon number, leads to a quadratic\ndivergence as $a^{-2}$. We argue that it is inherited from the continuum theory\nand can be subtracted off on the lattice following a similar manner in the\ncontinuum. We test this idea for quenched quark number susceptibilities and\ndemonstrate a finite continuum limit numerically.",
        "positive": "Recent lattice results on finite temperature and density QCD, part I: We discuss recent progress made studies of bulk thermodynamics of strongly\ninteracting matter through lattice simulations of QCD with an almost physical\nlight and strange quark mass spectrum. We present results on the QCD equation\nof state at vanishing and non-vanishing quark chemical potential and show first\nresults on baryon number and strangeness fluctuations, which might be measured\nin event-by-event fluctuations in low energy runs at RHIC as well as at FAIR."
    },
    {
        "anchor": "Finite-volume corrections to the leading-order hadronic contribution to\n  $g_\u03bc-2$: We present preliminary results of a 2+1-flavor study of finite-volume effects\nin the lattice QCD computation of the leading-order hadronic contribution to\nthe muon anomalous magnetic moment. We also present methods for obtaining\ndirectly the invariant hadronic polarization function, $\\Pi(Q^2)$, and the\nAdler function at all discrete lattice values of $Q^2$, including $Q^2=0$.\nResults are obtained with HEX-smeared clover fermions.",
        "positive": "N=4 Supersymmetry on a Space-Time Lattice: Maximally supersymmetric Yang--Mills theory in four dimensions can be\nformulated on a space-time lattice while exactly preserving a single\nsupersymmetry. Here we explore in detail this lattice theory, paying particular\nattention to its strongly coupled regime. Targeting a theory with gauge group\nSU(N), the lattice formulation is naturally described in terms of gauge group\nU(N). Although the U(1) degrees of freedom decouple in the continuum limit we\nshow that these degrees of freedom lead to unwanted lattice artifacts at strong\ncoupling. We demonstrate that these lattice artifacts can be removed, leaving\nbehind a lattice formulation based on the SU(N) gauge group with the expected\napparently conformal behavior at both weak and strong coupling."
    },
    {
        "anchor": "Effective Scalar Field Theory for the Electroweak Phase Transition: We investigate an effective model for the finite temperature restoration\nphase transition of the electroweak theory. It is obtained by dimensional\nreduction of the $3+1$ dimensional full theory and by subsequent integration\nover all static gauge degrees of freedom. The resulting theory corresponds to a\n$3$-dimensional $O(4)$ ferromagnet containing cubic and quartic terms of the\nfield in its potential function. Possible nonperturbative effects of a magnetic\nscreening mass are parametrically included in the potential. We analyse the\ntheory using mean field and numerical Monte Carlo (MC) simulation methods. At\nthe value of the physical Higgs mass, $m_H=37~{\\rm GeV}$, considered in the\npresent investigation, we find a discontinuous symmetry restoring phase\ntransition. We determine the critical temperature, order parameter jump,\ninterface tension and latent heat characteristics of the transition. The Monte\nCarlo results indicate a somewhat weaker first order phase transition as\ncompared to the mean field treatment, demonstrating that non-perturbative\nfluctuations of the Higgs field are relevant. This effect is especially\nimportant for the interface tension. Any observation of hard first order\ntransition could result only from non-perturbative effects related to the gauge\ndegrees of freedom.",
        "positive": "Gluon Propagator in Maximally Abelian Gauge and Abelian Dominance for\n  Long-Range Interaction: We study the gluon propagator in the MA gauge with the lattice QCD Monte\nCarlo simulation. The simulation is performed using the heat-bath algorithm on\nthe SU(2) lattice with $12^3 \\times 24$ and $\\beta = 2.3, 2.35$. The propagator\nof the off-diagonal charged gluon behaves as the massive gauge boson and\nprovides the short-range interaction, while the diagonal gluon propagates long\ndistance. This is the origin of the abelian dominance in the long-range\nphysics."
    },
    {
        "anchor": "Another weak first order deconfinement transition: three-dimensional\n  SU(5) gauge theory: We examine the finite-temperature deconfinement phase transition of\n(2+1)-dimensional SU(5) Yang-Mills theory via non-perturbative lattice\nsimulations. Unsurprisingly, we find that the transition is of first order,\nhowever it appears to be weak. This fits naturally into the general picture of\n\"large\" gauge groups having a first order deconfinement transition, even when\nthe center symmetry associated with the transition might suggest otherwise.",
        "positive": "Study of the Couplings of QED and QCD from the Adler Function: The contribution from hadronic vacuum polarisation effects is responsible for\na large fraction of the theoretical uncertainty in the running of the QED\ncoupling. The current level of uncertainty has become a limitation for\nelectroweak precision tests. We use lattice QCD simulations with two flavours\nof O$(a)$ improved Wilson fermions to determine the Adler function in a broad\nrange of the momentum transfer $Q^2$. The running of the QED coupling,\nincluding valence contributions from $u$, $d$, $s$ and $c$ quarks, is compared\nto phenomenological results at intermediate $Q^2$ values. In the large $Q^2$\nregime, the lattice determination of the Adler function is fitted to\nperturbation theory in order to examine the feasibility of a determination of\nthe strong coupling constant."
    },
    {
        "anchor": "Applying machine learning methods to prediction problems of lattice\n  observables: We discuss the prediction of critical behavior of lattice observables in\nSU(2) and SU(3) gauge theories. We show that feed-forward neural network,\ntrained on the lattice configurations of gauge fields as input data, finds\ncorrelations with the target observable, which is also true in the critical\nregion where the neural network has not been trained. We have verified that the\nneural network constructs a gauge-invariant function and this property does not\nchange over the entire range of the parameter space.",
        "positive": "Alpha_s from the non-perturbatively renormalised lattice three-gluon\n  vertex: We compute the running QCD coupling on the lattice by evaluating two-point\nand three-point off-shell gluon Green's functions in a fixed gauge and imposing\nnon-perturbative renormalisation conditions on them. Our exploratory study is\nperformed in the quenched approximation at beta=6.0 on 16^4 and 24^4 lattices.\nWe show that, for momenta in the range 1.8-2.3 Gev, our coupling runs according\nto the two-loop asymptotic formula, allowing a precise determination of the\ncorresponding Lambda parameter. The role of lattice artifacts and finite-volume\neffects is carefully analysed and these appear to be under control in the\nmomentum range of interest. Our renormalisation procedure corresponds to a\nmomentum subtraction scheme in continuum field theory, and therefore lattice\nperturbation theory is not needed in order to match our results to the MSbar\nscheme, thus eliminating a major source of uncertainty in the determination of\nalpha_MSbar. Our method can be applied directly to the unquenched case."
    },
    {
        "anchor": "Exclusive Channel Study of the Muon HVP: The Hadronic Vacuum Polarization (HVP) is a dominant contribution to the\ntheoretical uncertainty of the muon anomalous magnetic moment. The uncertainty\nin a lattice QCD calculation of the connected light-quark contribution to the\nHVP is dominated by the long-distance region of the vector correlation\nfunction. Explicit studies of the exclusive channels of the HVP diagram make it\npossible to reconstruct the long-distance behavior of the correlation function.\nThis removes most of the statistical uncertainty of the correlation function.\nIn these proceedings, preliminary results of an exclusive study of the isospin\nsymmetric connected-only vector-vector correlation function using a hybrid of\ndistillation and A2A techniques are presented. The computation is performed on\n2+1 flavor M\\\"obius Domain Wall Fermion ensembles with physical pion mass.\nReconstruction of the long-distance correlation function will enable\nlattice-only calculations of the HVP to achieve precision similar to estimates\nof the HVP from the R-ratio method on the timescale of the new experimental\nmeasurements of the muon anomalous magnetic moment.",
        "positive": "Solving Gauss's Law on Digital Quantum Computers with Loop-String-Hadron\n  Digitization: We show that using the loop-string-hadron (LSH) formulation of SU(2) lattice\ngauge theory (arXiv:1912.06133) as a basis for digital quantum computation\neasily solves an important problem of fundamental interest: implementing gauge\ninvariance (or Gauss's law) exactly. We first discuss the structure of the LSH\nHilbert space in $d$ spatial dimensions, its truncation, and its digitization\nwith qubits. Error detection and mitigation in gauge theory simulations would\nbenefit from physicality \"oracles,'\"so we decompose circuits that flag gauge\ninvariant wavefunctions. We then analyze the logical qubit costs and entangling\ngate counts involved with the protocols. The LSH basis could save or cost more\nqubits than a Kogut-Susskind-type representation basis, depending on how the\nbases are digitized as well as the spatial dimension. The numerous other clear\nbenefits encourage future studies into applying this framework."
    },
    {
        "anchor": "Experiences with OpenMP in tmLQCD: An overview is given of the lessons learned from the introduction of\nmulti-threading using OpenMP in tmLQCD. In particular, programming style,\nperformance measurements, cache misses, scaling, thread distribution for hybrid\ncodes, race conditions, the overlapping of communication and computation and\nthe measurement and reduction of certain overheads are discussed. Performance\nmeasurements and sampling profiles are given for different implementations of\nthe hopping matrix computational kernel.",
        "positive": "Topologically Unquenched QCD: Prospects from an explorative study in\n  2-flavour QED(2): The concept of simulating a variant of QCD with sea quarks which interact\nwith the gluon configuration only via global gluonic quantities like $\\int\nF\\tilde F dx$ and $\\int FF dx$ is tested for the case of the massive 2-flavour\nSchwinger model. It is found to amount to an importance sampling method which\ngenerates -at essentially the costs of a quenched run- an ensemble in between a\nfull and a quenched one, thus providing a competitive alternative to the\nquenched approximation."
    },
    {
        "anchor": "Multiscale Monte Carlo equilibration: Pure Yang-Mills theory: We present a multiscale thermalization algorithm for lattice gauge theory,\nwhich enables efficient parallel generation of uncorrelated gauge field\nconfigurations. The algorithm combines standard Monte Carlo techniques with\nideas drawn from real space renormalization group and multigrid methods. We\ndemonstrate the viability of the algorithm for pure Yang-Mills gauge theory for\nboth heat bath and hybrid Monte Carlo evolution, and show that it ameliorates\nthe problem of topological freezing up to controllable lattice spacing\nartifacts.",
        "positive": "Mass Relation Between Top and Bottom Quarks: In the framework of the recently proposed electroweak theory on a Planck\nlattice, we are able to solve approximately the lattice Dyson equation for the\nfermion self-energy functions, and obtain the ratio between the masses of the\n$t-$ and $b-$ quarks in terms of the electroweak coupling constants. The\npredicted top mass agrees with recent determinations from electroweak\nobservables."
    },
    {
        "anchor": "Z(3)-symmetric effective theory of hot QCD: We study a three dimensional Z(3)-symmetric effective theory of high\ntemperature QCD. The exact lattice-continuum relations, needed in order to\nperform lattice simulations with physical parameters, are computed to order\nO(a^0) in lattice perturbation theory. Lattice simulations are performed to\ndetermine the phase structure of a subset of the parameter space.",
        "positive": "Non-perturbative definition of five-dimensional gauge theories on the\n  R^4 x S^1/Z_2 orbifold: We construct a Z_2 orbifold projection of SU(N) gauge theories formulated in\nfive dimensions with a compact fifth dimension. We show through a\nnon-perturbative argument that no boundary mass term for the Higgs field,\nidentified with some of the fifth dimensional components of the gauge field, is\ngenerated, which would be quadratically divergent in the five-dimensional\nultraviolet cutoff. This opens the possibility of studying these theories\nnon-perturbatively in order to establish if they can be used as effective\nweakly interacting theories at low energies. We make preparations for a study\non the lattice. In particular we show that only Dirichlet boundary conditions\nare needed, which specify the breaking pattern of the gauge group at the\norbifold fixpoints."
    },
    {
        "anchor": "Complex Langevin dynamics for dynamical QCD at nonzero chemical\n  potential: a comparison with multi-parameter reweighting: We study lattice QCD at non-vanishing chemical potential using the complex\nLangevin equation. We compare the results with multi-parameter reweighting both\nfrom $\\mu=0$ and phase quenched ensembles. We find a good agreement for lattice\nspacings below $\\approx$0.15 fm. On coarser lattices the complex Langevin\napproach breaks down. Four flavors of staggered fermions are used on $N_t=4, 6$\nand 8 lattices. For one ensemble we also use two flavors to investigate the\neffects of rooting.",
        "positive": "Geometry of three dimensional vacuum domains in four dimensional SU(2)\n  gluodynamics: We review briefly recent results of lattice simulations on 3d domains in the\nvacuum state of SU(2) gluodynamics. The defects are defined as unification of\nall the negative links in central projection under condition that the total\nnumber of negative links is minimized. In the continuum limit, negative links\ncorrespond, generally speaking to singular fields. The data indicate that total\nvolume of the defects scales in physical units. We consider also correlator of\nnegative links. The correlator scales in physical units as well, within the\nerror bars. A new observation reported here is a strong anisotropy of the\ncorrelator."
    },
    {
        "anchor": "Pion electromagnetic form factor from full lattice QCD: We present preliminary results from the first calculation of the pion\nelectromagnetic form factor at physical light quark masses. This form factor\nparameterises the deviations from the behaviour of a point-like particle when a\nphoton hits the pion. These deviations result from the internal structure of\nthe pion and can thus be calculated in QCD. We use three sets (different\nlattice spacings) of n_f=2+1+1 lattice configurations generated by the MILC\ncollaboration. The Highly Improved Staggered Quark formalism (HISQ) is used for\nall of the sea and valence quarks. Using lattice configurations with u/d quark\nmasses very close to the physical value is an advantage, as we avoid the chiral\nextrapolation. We study the shape of the vector (f_+) form factor in the q^2\nrange from 0 to -0.12 GeV^2 and extract the mean square radius, <r^2_v>. The\nshape of the vector form factor and the resulting radius is compared with\nexperiment.",
        "positive": "Parton distribution functions of $\u0394^+$ on the lattice: We present results for renormalized matrix elements related to the\nunpolarized quasi-distribution function of the $\\Delta^+$ baryon making use of\nthe large momentum effective theory. Two ensembles of $N_f=2+1+1$ twisted mass\nfermions with a clover term and pion masses of 250 MeV and 330 MeV are\nanalyzed. We employ momentum smearing to improve the overlap with the boosted\n$\\Delta$ state significantly reducing in this way the statistical error of both\ntwo- and three-point functions."
    },
    {
        "anchor": "Computation of masses of quarkonium bound states using heavy quark\n  potentials from lattice QCD: We compute masses of bottomonium and charmonium bound states using a\nSchr\\\"odinger equation with a heavy quark-antiquark potential including $1/m$\nand $1/m^2$ corrections previously derived in potential Non-Relativistic QCD\nand computed with lattice QCD. This is a preparatory step for a future project,\nwhere we plan to take into account similar corrections to study quarkonium\nresonances and tetraquarks above the lowest meson-meson thresholds.",
        "positive": "Spectrum of Relativistic Fermions in a 2d Doped Lattice: Motivated by some previous work on fermions on random lattices and by\nsuggestions that impurities could trigger parity breaking in 2d crystals, we\nhave analyzed the spectrum of the Dirac equation on a two dimensional square\nlattice where sites have been removed randomly --- a doped lattice. We have\nfound that the system is well described by a sine-Gordon action. The solitons\nof this model are the lattice fermions, which pick a quartic interaction due to\nthe doping and become Thirring fermions. They also get an effective mass\ndifferent from the lagrangian mass. The system seems to exhibit spontaneous\nsymmetry breaking, exactly as it happens for a randomly triangulated lattice.\nThe associated ``Goldstone boson\" is the sine-Gordon scalar. We argue, however,\nthat the peculiar behaviour of the chiral condensate is due to finite size\neffects."
    },
    {
        "anchor": "Latest Results from the SGO Collaboration: We present results for the spectrum and decay constants of B mesons from\nNRQCD using dynamical configurations at $\\beta=5.6$ with two flavours of\nstaggered fermions. The light quarks are generated using the Clover action with\ntadpole improvement.",
        "positive": "Masses of the conjectured H-dibaryon at different temperatures: We present a lattice QCD determination of masses of the conjectured\nH-dibaryon $m_H$ at nine different temperatures $T/T_c =0.24, 0.63, 0.76, 0.84,\n0.95, 1.09, 1.27, 1.52, 1.90$. In the meantime, the masses of baryons $N$,\n$\\Sigma$, $\\Xi$ and $\\Lambda$ at different temperatures are also computed. The\nsimulation is performed on anisotropic lattice with $N_f=2+1$ flavours of\nclover fermion at quark mass which corresponds to $m_\\pi=384(4) {\\rm MeV} $.\nThe thermal ensembles were provided by the FASTSUM collaboration and the zero\ntemperature ensembles by the Hadspec collaboration. We also calculate the\nspectral density of the correlation function of those particles. The spectral\ndensity distributions show rich peak structure at the lowest temperature, while\nat intermediate temperatures, the mass values of those particles obtained by\nfitting procedure reflect a two-peak structure. While the spectral density for\noctet baryons becomes smooth at $T/T_c = 1.27, 1.52, 1.90$, the spectral\ndensity for H-dibaryon becoms smooth at $T/T_c = 1.90$. The negative mass\ndifference $\\Delta m = m_H - 2\\,m_{\\Lambda} $ of H-dibaryon and $\\Lambda$ pair\nat $T/T_c =0.24 $ is estimated to be $\\Delta m = -92(12) {\\rm MeV}$ which\nsuggests there exists a bound H-dibaryon state."
    },
    {
        "anchor": "Quantum chromodynamics with various number of flavors: The phase structure of QCD with various number of flavors is studied for\nWilson quarks. For the case of $N_F=3$ we find that the finite temperature\ndeconfining transition is of first order in the chiral limit on an $N_t=4$\nlattice. Together with our previous results that the deconfining transition in\nthe chiral limit is continuous for $N_F=2$ and is first order for $N_F=6$, the\norder of the transition is found to be consistent with a prediction of\nuniversality. The case of $SU(2)$ QCD is also studied in the strong coupling\nlimit and the phase structure is found to be quite similar to the case of\n$SU(3)$: There exists a critical number of flavors $N_F^*$ and for $N_F \\geq\nN_F^*$ the confinement is broken even in the strong coupling limit for light\nquarks. $N_F^*=3$ corresponding to 7 for $SU(3)$.",
        "positive": "Lattice QCD with Eight Degenerate Quark Flavors: We report on simulations of QCD with many flavors of degenerate quarks, the\nDBW2 gauge action and naive staggered fermions, using the rational hybrid Monte\nCarlo algorithm. We primarily focus on eight degenerate quark flavors where a\nvariety of values of the coupling constant and quark mass have been used in the\nsimulations. The scaling behavior of the hadron spectrum and the string tension\nof the heavy quark potential is studied, to probe whether the zero temperature,\ncontinuum limit of the theory breaks chiral symmetry."
    },
    {
        "anchor": "Infrared exponents of Yang-Mills theory: In this talk I summarise recent results on the infrared exponents of\nSU($N_c$)-Yang-Mills theory. I discuss a self-consistent power law solution for\nthe Dyson-Schwinger equations for general 1PI-Greens functions in the infrared.\nThe corresponding running coupling has a fixed point at zero momentum, which\nturns out to be universal and gauge invariant within a class of transverse\ngauges. When calculated on a torus the infrared exponents of the ghost and\ngluon propagators differ from the corresponding continuum solutions. They\nagree, however, well with results from lattice calculations.",
        "positive": "Can Merons Describe Confinement?: Merons, conjectured as a semiclassical mechanism for color confinement in\nQCD, are topological charge-1/2, singular solutions to the classical Yang-Mills\nequations of motion. I will discuss how lattice techniques can extend the study\nof merons to nonsingular stationary solutions without destroying properties\nbelieved to be essential for confinement, and how zero modes can be used to\nidentify these gauge field configurations in stochastic evaluations of the\nlattice QCD path integral."
    },
    {
        "anchor": "Topological Charge of Lattice Abelian Gauge Theory: Configuration space of abelian gauge theory on a periodic lattice becomes\ntopologically disconnected by excising exceptional gauge field configurations.\nIt is possible to define a U(1) bundle from the nonexceptional link variables\nby a smooth interpolation of the transition functions. The lattice analogue of\nChern character obtained by a cohomological technique based on the\nnoncommutative differential calculus is shown to give a topological charge\nrelated to the topological winding number of the U(1) bundle.",
        "positive": "Projection of the low-lying eigenmodes of the overlap Dirac operator in\n  lattice QCD: We outline our implementation of the adaptive thick-restart Lanczos algorithm\n($a$-TRLan) for the projection of the low-lying eigenmodes of the overlap Dirac\noperator in lattice QCD, and compare the performances of our code and the\nwidely used package ARPACK."
    },
    {
        "anchor": "Strong-coupling lattice study for QCD phase diagram including both\n  chiral and deconfinement dynamics: We investigate the QCD phase diagram by using the strong-coupling expansion\nof the lattice QCD with one species of staggered fermion and the Polyakov loop\neffective action at finite temperature (T) and quark chemical potential (mu).\nWe derive an analytic expression of effective potential Feff including both the\nchiral (U(1)) and the deconfinement (Z_Nc) dynamics with finite coupling\neffects in the mean-field approximation. The Polyakov loop increasing rate\n(dl/dT) is found to have two peaks as a function of T for small quark masses.\nOne of them is the chiral-induced peak associated with the rapid decrease of\nthe chiral condensate. The temperature of the other peak is almost independent\nof the quark mass or chemical potential, and this peak is interpreted as the\nZ_Nc-induced peak.",
        "positive": "Leading-order hadronic contribution to g-2 from lattice QCD: We calculate the leading-order hadronic correction to the anomalous magnetic\nmoments of each of the three charged leptons in the Standard Model: the\nelectron, muon and tau. Working in two-flavor lattice QCD, we address\nessentially all sources of systematic error: lattice artifacts, finite-size\neffects, quark-mass extrapolation, momentum extrapolation and disconnected\ndiagrams. The most significant remaining systematic error, the exclusion of the\nstrange and charm quark contributions, will be addressed in our four-flavor\ncalculation. We achieve a statistical accuracy of 2% or better for the physical\nvalues for each of the three leptons and the systematic errors are at most\ncomparable."
    },
    {
        "anchor": "Analysis of the $N_f=2+1$ lattice QCD results on the lowest-lying baryon\n  masses using covariant ChPT: We review recent progress in the understanding of low-energy baryon structure\nby means of chiral perturbation theory. In particular, we discuss the\napplication of this formalism to the description of the quark mass dependence\nof recent Lattice QCD results on the masses. We present the chiral\nextrapolation of those of the PACS-CS and LHP collaborations and we predict the\nbaryonic sigma-terms.",
        "positive": "Area-preserving diffeomorphisms in gauge theory on a non-commutative\n  plane: a lattice study: We consider Yang-Mills theory with the U(1) gauge group on a non-commutative\nplane. Perturbatively it was observed that the invariance of this theory under\narea-preserving diffeomorphisms (APDs) breaks down to a rigid subgroup SL(2,R).\nHere we present explicit results for the APD symmetry breaking at finite gauge\ncoupling and finite non-commutativity. They are based on lattice simulations\nand measurements of Wilson loops with the same area but with a variety of\ndifferent shapes. Our results are consistent with the expected loss of\ninvariance under APDs. Moreover, they strongly suggest that non-perturbatively\nthe SL(2,R) symmetry does not persist either."
    },
    {
        "anchor": "Testing a Fourier Accelerated Hybrid Monte Carlo Algorithm: We describe a Fourier Accelerated Hybrid Monte Carlo algorithm suitable for\ndynamical fermion simulations of non-gauge models. We test the algorithm in\nsupersymmetric quantum mechanics viewed as a one-dimensional Euclidean lattice\nfield theory. We find dramatic reductions in the autocorrelation time of the\nalgorithm in comparison to standard HMC.",
        "positive": "Pion distribution amplitude from Euclidean correlation functions: Following the proposal in [1], we study the feasibility to calculate the pion\ndistribution amplitude (DA) from suitably chosen Euclidean correlation\nfunctions at large momentum. In our lattice study we employ the novel momentum\nsmearing technique [2,3]. This approach is complementary to the calculations of\nthe lowest moments of the DA using the Wilson operator product expansion and\navoids mixing with lower dimensional local operators on the lattice. The\ntheoretical status of this method is similar to that of quasi-distributions\n[4], which has recently been applied to the same problem in [5]. The\nsimilarities and differences between these two techniques are highlighted."
    },
    {
        "anchor": "A Gauge-Fixing Action for Lattice Gauge Theories: We present a lattice gauge-fixing action $S_{gf}$ with the following\nproperties: (a) $S_{gf}$ is proportional to the trace of $(\\sum_\\mu\n\\partial_\\mu A_\\mu)^2$, plus irrelevant terms of dimension six and higher; (b)\n$S_{gf}$ has a unique absolute minimum at $U_{x,\\mu}=I$. Noting that the\ngauge-fixed action is not BRST invariant on the lattice, we discuss some\nimportant aspects of the phase diagram.",
        "positive": "Results from a study of the Nambu--Jona-Lasinio model on the lattice: The main results of our analysis of the two flavor Nambu--Jona-Lasinio model\nwith $SU(2) \\times SU(2)$ chiral symmetry on the four--dimensional hypercubic\nlattice with naive and Wilson fermions are presented. Large $N$ techniques and\nnumerical simulations are used to study various properties of the model. The\nscalar and pseudoscalar spectrum, the approach to the continuum and chiral\nlimits, the size of the $1/N$ corrections, and the effects of the zero momentum\nfermionic modes on finite lattices are studied. Also, some interesting\nobservations are made by viewing the model as an embedding theory of the Higgs\nsector."
    },
    {
        "anchor": "A study of chiral symmetry in quenched QCD using the Overlap-Dirac\n  operator: We compute fermionic observables relevant to the study of chiral symmetry in\nquenched QCD using the Overlap-Dirac operator for a wide range of the fermion\nmass. We use analytical results to disentangle the contribution from exact zero\nmodes and simplify our numerical computations. Details concerning the numerical\nimplementation of the Overlap-Dirac operator are presented.",
        "positive": "Spectroscopy of B_s and D_s Mesons: We study Bs and Ds spectroscopy in quenched lattice QCD using the Fermilab\napproach to heavy quarks. We obtain results at four lattice spacings, $a$,\nusing $O(a)$-improved Wilson quarks. We compare and contrast the various\nmethods for heavy quarks on the lattice, discussing discussing which methods\nwork best for different physical systems and the ease with which calculations\nmay be performed."
    },
    {
        "anchor": "Nondecoupling of Heavy Mirror-Fermion: According to one-loop perturbation theory, fermions whose masses are totally\ngenerated from Yukawa couplings do not decouple in the heavy mass limit. We\ninvestigate this issue nonperturbatively in the strong coupling regime of the\nchiral $U(1)$ mirror-fermion model in four dimensions. Our numerical results,\nobtained on $6^3\\cdot 16$, $6^3\\cdot 24$ and $8^3\\cdot 16$ lattices, indicate\nnondecoupling of heavy fermion and mirror-fermion, thus supporting the one-loop\npicture.",
        "positive": "Electromagnetic superconductivity of vacuum induced by strong magnetic\n  field: numerical evidence in lattice gauge theory: Using numerical simulations of quenched SU(2) gauge theory we demonstrate\nthat an external magnetic field leads to spontaneous generation of quark\ncondensates with quantum numbers of electrically charged rho mesons if the\nstrength of the magnetic field exceeds the critical value eBc = 0.927(77) GeV^2\nor Bc =(1.56 \\pm 0.13) 10^{16} Tesla. The condensation of the charged rho\nmesons in strong magnetic field is a key feature of the magnetic-field-induced\nelectromagnetic superconductivity of the vacuum."
    },
    {
        "anchor": "Study of the SU(2) High Density System with Wilson Fermion: We investigate high density state of SU(2) QCD in the case of the Wilson\nfermions with Iwasaki improved action. Based on the Woodbery formula, the ratio\nof fermion determinants is evaluated at each step of the Metropolis link\nupdate. At $\\beta=0.7$, for $\\kappa = 0.150$, and $\\kappa = 0.175$, we\ncalculate thermodynamical quantities, such as, baryon number density, Polyakov\nline, and the energy density of gluon sector with chemical potential $\\mu$=0 to\n0.9 on the $4^{3} \\times 8$ lattice. The susceptibility of the Polyakov line to\nthe chemical potential shows peak at around $\\mu = 0.7$ which indicates the\ndeconfinement phase transition. Behavior of the meson and diquark propagators\nwith finite chemical potential are also investigated at both side of the peak.",
        "positive": "Optimization of the Oktay-Kronfeld Action Conjugate Gradient Inverter: Improving the Fermilab action to third order in heavy quark effective theory\nyields the Oktay-Kronfeld action, a promising candidate for precise\ncalculations of the spectra of heavy quark systems and weak matrix elements\nrelevant to searches for new physics. We have optimized the bi-stabilized\nconjugate gradient inverter in the SciDAC QOPQDP library and are developing a\nGPU code. The action is rewritten and the needed gauge-link combinations are\nprecalculated. In tests with a MILC coarse lattice, this procedure accelerates\nthe inverter by a factor of four. The remaining floating-point operations are\nmostly simple matrix multiplications between gauge links and fermion vectors,\nwhich we accelerate by more than an order of magnitude by using CUDA. Further\ngains could be achieved by using QUDA."
    },
    {
        "anchor": "Lattice and renormalons in heavy quark physics: Perturbative expansions of QCD observables in powers of $\\alpha_s$ are\nbelieved to be asymptotic and non-Borel summable due to the existence of\nsingularities in the Borel plane (renormalons). This fact is connected with the\nfactorization of scales (which is inherent to QCD and asymptotic freedom) and\njeopardizes the convergence of the perturbative expansion and the accurate\ndetermination of power-suppressed corrections. This problem is more acute for\nphysical systems composed by one or more heavy quarks. In lattice regulations,\nit reflects on the appearance of power-like divergences in the inverse of the\nlattice spacing for a series of quantities ($\\bar \\Lambda$, gluelump masses,\nthe singlet and hybrid potentials, ...) making that the continuum limit can not\nbe reached for them. Nevertheless, all these problems are solved within the\nframework of effective field theories with renormalon substraction. This allows\nus to obtain convergent perturbative series and to unambiguously define power\ncorrections. In particular, one can connect with lattice results. Remarkably\nenough the dependence on the lattice spacing can be predicted by perturbation\ntheory. This framework has been applied to the prediction of the gluelump\nmasses and the singlet and octet (hybrid) potentials at short distances, as\nwell as to their comparison with lattice simulations. Overall, very good\nagreement with data is obtained.",
        "positive": "A Novel Multiple-Time Scale Integrator for the Hybrid Monte Carlo\n  Algorithm: Hybrid Monte Carlo simulations that implement the fermion action using\nmultiple terms are commonly used. By the nature of their formulation they\ninvolve multiple integration time scales in the evolution of the system through\nsimulation time. These different scales are usually dealt with by the\nSexton-Weingarten nested leapfrog integrator. In this scheme the choice of time\nscales is somewhat restricted as each time step must be an exact multiple of\nthe next smallest scale in the sequence. A novel generalisation of the nested\nleapfrog integrator is introduced which allows for far greater flexibility in\nthe choice of time scales, as each scale now must only be an exact multiple of\nthe smallest step size."
    },
    {
        "anchor": "2+1 Flavor Lattice QCD with Luescher's Domain-Decomposed HMC Algorithm: We report on a study of 2+1 flavor lattice QCD with the $O(a)$-improved\nWilson quarks on a $16^3\\times 32$ lattice at the lattice spacing $1/a\\approx\n2$GeV employing Luescher's domain-decomposed HMC(LDDHMC) algorithm. This is\ndedicated to a preliminary study for the PACS-CS project which plans to\ncomplete the Wilson-clover $N_f=2+1$ program lowering the up-down quark masses\nclose to the physical values as much as possible. We focus on three issues: (i)\nhow light quark masses we can reach with LDDHMC, (ii) efficiency of the\nalgorithm compared with the conventional HMC, (iii) parameter choice for the\nproduction runs on PACS-CS.",
        "positive": "Thermodynamics of the QCD plasma and the large-N limit: The equilibrium thermodynamic properties of the SU(N) plasma at finite\ntemperature are studied non-perturbatively in the large-N limit, via lattice\nsimulations. We present high-precision numerical results for the pressure,\ntrace of the energy-momentum tensor, energy density and entropy density of\nSU(N) Yang-Mills theories with N=3, 4, 5, 6 and 8 colors, in a temperature\nrange from 0.8T_c to 3.4T_c (where T_c denotes the critical deconfinement\ntemperature). The results, normalized according to the number of gluons, show a\nvery mild dependence on N, supporting the idea that the dynamics of the\nstrongly-interacting QCD plasma could admit a description based on large-N\nmodels. We compare our numerical data with general expectations about the\nthermal behavior of the deconfined gluon plasma and with various theoretical\ndescriptions, including, in particular, the improved holographic QCD model\nrecently proposed by Kiritsis and collaborators. We also comment on the\nrelevance of an AdS/CFT description for the QCD plasma in a phenomenologically\ninteresting temperature range where the system, while still strongly-coupled,\napproaches a `quasi-conformal' regime characterized by approximate scale\ninvariance. Finally, we perform an extrapolation of our results to the N to\n$\\infty$ limit."
    },
    {
        "anchor": "Spontaneous generation of chromomagnetic fields at finite temperature in\n  the SU(3) gluodynamics on a lattice: The spontaneous generation of homogeneous chromomagnetic fields in the\nlattice SU(3) gluodynamics is investigated in the deconfinement phase of the\nmodel. A new approach based on direct measurements of the field strength on a\nlattice is developed. Vacuum magnetization is established by its influence on\nthe probability density function of the simulated field strength. It is found\nthat both the chromomagnetic fields corresponding to the diagonal SU(3)\ngenerators are simultaneously condensated and appear to be spatially\nco-directed. No vacuum magnetization is detected for the other SU(3)\ncomponents. The temperature dependence of the spontaneously generated fields in\nphysical units is fitted in the temperature interval 200 MeV - 200 GeV as the\nusual power law with the anomalous dimension.",
        "positive": "Vector boson mass generation without new fields: Previously a model of only vector fields with a local U(2) symmetry was\nintroduced for which one finds a massless U(1) photon and a massive SU(2)\nvector boson in the lattice regularization. Here it is shown that quantization\nof its classical continuum action leads to perturbative renormalization\ndifficulties. But, non-perturbative Monte Carlo calculations favor the\nexistence of a quantum continuum limit."
    },
    {
        "anchor": "Strongly coupled U(1) lattice gauge theory as a microscopic model of\n  Yukawa theory: Dynamical chiral symmetry breaking in a strongly coupled U(1) lattice gauge\nmodel with charged fermions and scalar is investigated by numerical simulation.\nSeveral composite neutral states are observed, in particular a massive fermion.\nIn the vicinity of the tricritical point of this model we study the effective\nYukawa coupling between this fermion and the Goldstone boson. The perturbative\ntriviality bound of Yukawa models is nearly saturated. The theory is quite\nsimilar to strongly coupled Yukawa models for sufficiently large coupling\nexcept the occurrence of an additional state -- a gauge ball of mass about half\nthe mass of the fermion.",
        "positive": "Towards the determination of sigma terms for the baryon octet on\n  $N_\\mathrm{f} = 2+1$ CLS ensembles: A lot of progress has been made in the determination of nucleon sigma terms.\nIn this work we consider the sigma terms of the other octet baryons as well.\nThese are determined on CLS gauge field ensembles employing the L\\\"uscher-Weisz\ngluon action and the Sheikholeslami-Wohlert fermion action with $N_\\mathrm{f} =\n2 + 1$. The ensembles have pion masses ranging from ${410}\\,\\mathrm{MeV}$ down\nto the physical value and lattice spacings covering a range between\n${0.09}\\,\\mathrm{fm}$ and ${0.04}\\,\\mathrm{fm}$. We present some preliminary\nresults for $a\\approx 0.06$ fm along a trajectory where the sum of the sea\nquark masses is kept constant, focusing on the quark mass dependence. We\ndiscuss multi-state fits to tackle the well-known problem of excited state\ncontamination and detail how we analyse connected and disconnected\ncontributions."
    },
    {
        "anchor": "First quenched results for the matrix elements of the B_{B_s} mixing\n  parameter in the static limit from tmQCD: We report on a non-perturbative study of the scale-dependent renormalization\nfactors of a multiplicatively renormalizable basis of Delta B=2 parity-odd\nfour-fermion operators in quenched lattice QCD. We also present some\npreliminary results of the matrix elements related to the mixing parameter of\nthe B_s-meson. In our lattice formulation, the heavy quark is treated in the\nstatic approximation, while the strange one belongs to a doublet of twisted\nmass fermions at full twist, i.e. with twist angle alpha=pi/2. In this\nframework, the parity-even Delta B=2 four-fermion operators responsible for the\nmixing are rotated onto a linear combination of parity-odd operators in the\nabove-mentioned basis. Their physical matrix elements between static B_s-mesons\nare extracted from lattice correlators with Schroedinger functional boundary\nconditions. We observe a suppression of excited state contributions to the\nB_{B_s} mixing parameter and speculate about possible explanations.",
        "positive": "Tensor networks for gauge field theories: Over the last decade tensor network states (TNS) have emerged as a powerful\ntool for the study of quantum many body systems. The matrix product states\n(MPS) are one particular class of TNS and are used for the simulation of\n(1+1)-dimensional systems. In this proceeding we use MPS to determine the\nelementary excitations of the Schwinger model in the presence of an electric\nbackground field. We obtain an estimate for the value of the background field\nwhere the one-particle excitation with the largest energy becomes unstable and\ndecays into two other elementary particles with smaller energy."
    },
    {
        "anchor": "Dominance of Sign Geometry and the Homogeneity of the Fundamental\n  Topological Structure: We propose and support the possibility that the shape of topological density\n2-point function in pure-glue QCD is crucially, and possibly entirely,\ndetermined by the space-time folding (geometry) of the double-sheet\nsign-coherent structure of Ref.[1], while the distribution of topological\ndensity within individual sheets only determines the overall magnitude of the\ncorrelator at finite physical distances. A specific manifestation of this,\ndiscussed here, is that the shape of the correlation function (encoding e.g.\nthe masses of pseudoscalar glueballs) is reproduced upon the replacement q(x)\n-> sgn(q(x)), i.e. by considering the double sheet of the same space-time\ngeometry but with constant magnitude of topological density. Combined with\nprevious results on the fundamental topological structure, this suggests that a\ncollective degree of freedom describing topological fluctuations of QCD vacuum\ncan be viewed as a global space-filling homogeneous double membrane. Selected\npossibilities for practical uses of this are discussed.",
        "positive": "Gribov Copies and Smeared Correlation Functions in Lattice QCD: We study the influence of Gribov copies in the Coulomb gauge on the smeared\nhadronic correlation functions that are involved in the determination of the B\nmeson decay constant. We find that the residual gauge freedom associated to\nGribov copies induces observable noise effects, though at the level of\nnumerical accuracy of our simulation these effects are not relevant to the\nfinal determination of f_B. Our results indicate that such effects may become\nimportant on bigger lattices."
    },
    {
        "anchor": "Computing the nucleon charge and axial radii directly at $Q^2=0$ in\n  lattice QCD: We describe a procedure for extracting momentum derivatives of nucleon matrix\nelements on the lattice directly at $Q^2=0$. This is based on the Rome method\nfor computing momentum derivatives of quark propagators. We apply this\nprocedure to extract the nucleon isovector magnetic moment and charge radius as\nwell as the isovector induced pseudoscalar form factor at $Q^2=0$ and the axial\nradius. For comparison, we also determine these quantities with the traditional\napproach of computing the corresponding form factors, i.e. $G^v_E(Q^2)$ and\n$G_M^v(Q^2)$ for the case of the vector current and $G_P^v(Q^2)$ and\n$G_A^v(Q^2)$ for the axial current, at multiple $Q^2$ values followed by\n$z$-expansion fits. We perform our calculations at the physical pion mass using\na 2HEX-smeared Wilson-clover action. To control the effects of excited-state\ncontamination, the calculations were done at three source-sink separations and\nthe summation method was used. The derivative method produces results\nconsistent with those from the traditional approach but with larger statistical\nuncertainties especially for the isovector charge and axial radii.",
        "positive": "Generating a non-perturbative mass gap using Feynman diagrams in an\n  asymptotically free theory: Using the example of a two dimensional four-fermion lattice field theory we\ndemonstrate that Feynman diagrams can generate a mass gap when massless\nfermions interact via a marginally relevant coupling. We introduce an infrared\ncutoff through the finite system size so that the perturbation series for the\npartition function and observables become convergent. We then use the Monte\nCarlo approach to sample sufficiently high orders of diagrams to expose the\npresence of a mass gap in the lattice model."
    },
    {
        "anchor": "Simplicial gauge theory and quantum gauge theory simulation: We propose a general formulation of simplicial lattice gauge theory inspired\nby the finite element method. Numerical tests of convergence towards continuum\nresults are performed for several SU(2) gauge fields. Additionaly, we perform\nsimplicial Monte Carlo quantum gauge field simulations involving measurements\nof the action as well as differently sized Wilson loops as functions of\n$\\beta$.",
        "positive": "QCD thermodynamics with dynamical fermions: In this thesis the finite temperature transition between confined and\ndeconfined matter is studied at zero and nonzero quark densities. The findings\nare relevant for the understanding of the evolution of the early Universe and\ncontemporary and upcoming heavy ion experiments. The results were obtained\nusing large-scale simulations on lattices with various physical extents and\nlattice spacings, at physical values of the parameters of the theory. First the\nphase diagram of QCD in the chemical potential-temperature plane is determined\nfor small chemical potentials via a Taylor-expansion technique. Second the\nequation of state is studied with 2+1 flavors of dynamical quarks. Finally, the\nequation of state is calculated in pure gauge theory up to extremely high\ntemperatures, where a comparison to perturbation theory is carried out."
    },
    {
        "anchor": "Applications of Machine Learning to Lattice Quantum Field Theory: There is great potential to apply machine learning in the area of numerical\nlattice quantum field theory, but full exploitation of that potential will\nrequire new strategies. In this white paper for the Snowmass community planning\nprocess, we discuss the unique requirements of machine learning for lattice\nquantum field theory research and outline what is needed to enable exploration\nand deployment of this approach in the future.",
        "positive": "Isovector electromagnetic form factors of the nucleon from lattice QCD\n  and the proton radius puzzle: We present results for the isovector electromagnetic form factors of the\nnucleon computed on the CLS ensembles with $N_f=2+1$ flavors of\n$\\mathcal{O}(a)$-improved Wilson fermions and an $\\mathcal{O}(a)$-improved\nvector current. The analysis includes ensembles with four lattice spacings and\npion masses ranging from 130 MeV up to 350 MeV and mainly targets the low-$Q^2$\nregion. In order to remove any bias from unsuppressed excited-state\ncontributions, we investigate several source-sink separations between 1.0 fm\nand 1.5 fm and apply the summation method as well as explicit two-state fits.\nThe chiral interpolation is performed by applying covariant chiral perturbation\ntheory including vector mesons directly to our form factor data, thus avoiding\nan auxiliary parametrization of the $Q^2$ dependence. At the physical point, we\nobtain $\\mu=4.71(11)_{\\mathrm{stat}}(13)_{\\mathrm{sys}}$ for the nucleon\nisovector magnetic moment, in good agreement with the experimental value and\n$\\langle\nr_\\mathrm{M}^2\\rangle~=~0.661(30)_{\\mathrm{stat}}(11)_{\\mathrm{sys}}\\,~\\mathrm{fm}^2$\nfor the corresponding square-radius, again in good agreement with the value\ninferred from the $ep$-scattering determination [Bernauer et~al., Phys. Rev.\nLett., 105, 242001 (2010)] of the proton radius. Our estimate for the isovector\nelectric charge radius, $\\langle r_\\mathrm{E}^2\\rangle =\n0.800(25)_{\\mathrm{stat}}(22)_{\\mathrm{sys}}\\,~\\mathrm{fm}^2$, however, is in\nslight tension with the larger value inferred from the aforementioned\n$ep$-scattering data, while being in agreement with the value derived from the\n2018 CODATA average for the proton charge radius."
    },
    {
        "anchor": "Low energy scattering phase shifts for meson-baryon systems: In this work, we calculate meson-baryon scattering phase shifts in four\nchannels using lattice QCD methods. From a set of calculations at four volumes,\ncorresponding to spatial sizes of 2, 2.5, 3, and 4 fm, and a pion mass of m_pi\n~ 390 MeV, we determine the scattering lengths and effective ranges for these\nsystems at the corresponding quark masses. We also perform the calculation at a\nlighter quark mass, m_pi ~ 230 MeV, on the largest volume. Using these\ndeterminations, along with those in previous work, we perform a chiral\nextrapolation of the scattering lengths to the physical point after correcting\nfor the effective range contributions using the multi-volume calculations\nperformed at m_pi ~ 390 MeV.",
        "positive": "Passing through the `chiral limit' in quenched QCD with Wilson fermions: We investigate the limit of vanishing quark mass in quenched lattice QCD with\nunimproved Wilson fermions at $\\beta=6.0$. Exploiting the correlations of\npropagators at different time slices we extract pion masses extremely close to\nthe `chiral limit', despite the presence of `exceptional configurations'. With\nthis at hand, the existence of quenched chiral logarithms can be demonstrated,\nprovided, finite size effects are small. With reference to the phase diagram\nproposed by Aoki also the range $\\kappa > \\kappa_c$ is investigated. The width\nof a potential parity-flavor violating phase can, if at all, hardly be\nresolved."
    },
    {
        "anchor": "A Variational Approach to the Structure and Thermodynamics of Linear\n  Polyelectrolytes with Coulomb and Screened Coulomb Interactions: A variational approach is used to calculate free energy and conformational\nproperties in polyelectrolytes. The true bond and Coulomb potentials are\napproximated by a trial isotropic harmonic energy containing monomer-monomer\nforce constants as variational parameters. By a judicious choice of\nrepresentation and the use of incremental matrix inversion, an efficient and\nfast-convergent iterative algorithm is constructed, that optimizes the free\nenergy. The computational demand scales as N^3. The method has the additional\nadvantage that the entropy is easily computed. An analysis of the high and low\ntemperature limits is given. Also, the variational formulation is shown to\nrespect the appropriate virial identities. The accuracy of the approximations\nintroduced are tested against Monte Carlo simulations for problem sizes ranging\nfrom N=20 to 1024. Very good performance is obtained for chains with unscreened\nCoulomb interactions. The addition of salt is described through a screened\nCoulomb interaction, for which the accuracy in a certain parameter range turns\nout to be inferior to the unscreened case. The reason is that the isotropic\nGaussian Ansatz becomes less efficient with shorter range interactions. As a\nby-product a very efficient Monte Carlo algorithm was developed for\ncomparisons, providing high statistics data for very large sizes - 2048\nmonomers.",
        "positive": "Continuum Goldstone spectrum of two-color QCD at finite density with\n  staggered quarks: We carry out lattice simulations of two-color QCD and spectroscopy at finite\ndensity with two flavors of rooted-staggered quarks and a diquark source term.\nAs in a previous four-flavor study, for small values of the inverse gauge\ncoupling we observe a Goldstone spectrum which reflects the symmetry-breaking\npattern of a Gaussian symplectic chiral random-matrix ensemble (GSE) with Dyson\nindex $\\beta_D=4$, which corresponds to any-color QCD with adjoint quarks in\nthe continuum instead of QC$_2$D wih fundamental quarks. We show that this\nunphysical behavior occurs only inside of the bulk phase of $SU(2)$ gauge\ntheory, where the density of $Z_2$ monopoles is high. Using an improved gauge\naction and a somewhat larger inverse coupling to suppress these monopoles, we\ndemonstrate that the continuum Goldstone spectrum of two-color QCD,\ncorresponding to a Gaussian orthogonal ensemble (GOE) with Dyson index\n$\\beta_D=1$, is recovered also with rooted-staggered quarks once simulations\nare performed away from the bulk phase. We further demonstrate how this change\nof random-matrix ensemble is reflected in the distribution of eigenvalues of\nthe Dirac operator. By computing the unfolded level spacings inside and outside\nof the bulk phase, we demonstrate that, starting with the low-lying eigenmodes\nwhich determine the infrared physics, the distribution of eigenmodes\ncontinuously changes from the GSE to the GOE one as monopoles are suppressed."
    },
    {
        "anchor": "A Quark-Antiquark Condensate in Three-Dimensional QCD: Three-dimensional lattice QCD is studied by Monte Carlo simulations within\nthe quenched approximation. At zero temperature a quark-antiquark condensate is\nobserved in the limit of vanishing quark masses. The condensate vanishes\ncontinuously at the finite-temperature deconfinement phase transition of the\ntheory. A natural interpretation of this phenomenon in the full theory with\ndynamical quarks is in terms of the spontaneous flavor symmetry breaking\n$U(N_f) \\to U(N_f/2)\\times U(N_f/2)$. In addition, the spectrum of low-lying\nDirac operator eigenvalues is computed and found to be consistent with a flat\ndistribution at zero temperature, in agreement with analytical predictions.",
        "positive": "Relativistic bottomonium spectrum from anisotropic lattices: We report on our results from a fully relativistic simulation of the quenched\nbottomonium spectrum. Using an anisotropic formulation of Lattice QCD, we were\nable to retain a very fine resolution into the temporal direction for a range\nof different lattice spacings. At fixed renormalized anisotropy we study the\nscaling properties of the spectrum and compare our results with\nnon-relativistic calculations."
    },
    {
        "anchor": "Numerical study of the scaling properties of SU(2) lattice gauge theory\n  in Palumbo non-compact regularization: In the framework of a non-compact lattice regularization of nonabelian gauge\ntheories we look, in the SU(2) case, for the scaling window through the\nanalysis of the ratio of two masses of hadronic states. In the two-dimensional\nparameter space of the theory we find the region where the ratio is constant,\nand equal to the one in the Wilson regularization. In the scaling region we\ncalculate the lattice spacing, finding it at least 20% larger than in the\nWilson case; therefore the simulated physical volume is larger.",
        "positive": "Decay constants of B-mesons from non-perturbative HQET with two light\n  dynamical quarks: We present a computation of B-meson decay constants from lattice QCD\nsimulations within the framework of Heavy Quark Effective Theory for the\nb-quark. The next-to-leading order corrections in the HQET expansion are\nincluded non-perturbatively. Based on Nf=2 gauge field ensembles, covering\nthree lattice spacings a (0.08-0.05)fm and pion masses down to 190MeV, a\nvariational method for extracting hadronic matrix elements is used to keep\nsystematic errors under control. In addition we perform a careful\nautocorrelation analysis in the extrapolation to the continuum and to the\nphysical pion mass limits. Our final results read fB=186(13)MeV, fBs=224(14)MeV\nand fBs/fB=1.203(65). A comparison with other results in the literature does\nnot reveal a dependence on the number of dynamical quarks, and effects from\ntruncating HQET appear to be negligible."
    },
    {
        "anchor": "Lattice Gross-Neveu model with domain-wall fermions: We investigate the two-dimensional lattice Gross-Neveu model, using the\ndomain-wall fermion formulation, as a toy model of lattice QCD. We study\nfeatures of the phase diagram related to the mechanism of chiral symmetry\nrestoration, and find that the parity-broken phase (Aoki phase) exists for\nfinite extent in the extra dimension ($N_s$). We also find that O(a) scaling\nviolation terms vanishes in the limit of $N_s\\to\\infty$.",
        "positive": "Hadron Structure in Lattice QCD: Recent progress in hadron structure calculations within lattice QCD is\nreviewed. Results on key observables such as the axial charge, the quark\nmomentum fraction and the spin content of the nucleon are discussed with focus\non open issues. Lattice QCD studies of the $\\gamma^* N\\rightarrow \\Delta$\ntransition as well as the $\\Delta$ form factors are also presented."
    },
    {
        "anchor": "Elucidating the Vacuum Structure of the Aoki Phase: In this paper, we discuss the vacuum structure of QCD with two flavors of\nWilson fermions, inside the Aoki phase. We provide numerical evidence, coming\nfrom HMC simulations in $4^4$, $6^4$ and $8^4$ lattices, supporting a vacuum\nstructure for this model at strong coupling more complex than the one assumed\nin the standard wisdom, with new vacua where the expectation value of\n$i\\bar\\psi\\gamma_5\\psi$ can take non-zero values, and which can not be\nconnected with the Aoki vacua by parity-flavour symmetry transformations.",
        "positive": "Wave functions and their use in spectroscopy and phenomenology: We describe the calculation of Coulomb gauge wave functions for light quark\nsystems, and their use as interpolating fields for excited state spectroscopy."
    },
    {
        "anchor": "Residual mass effects in improved domain wall fermions: In order to improve simulations with domain wall fermions (DWFs), it has been\nsuggested to project out a number of low-lying eigenvalues of the 4-dimensional\nDirac operator that generates the transfer matrix of DWF. We investigate how\nthis projection method affects chiral properties of quenched DWF. In\nparticular, we study the behaviour of the residual mass as a function of the\nsize of the extra dimension.",
        "positive": "Wilson Fermions at finite temperature: I conjecture on the phase structure expected for lattice gauge theory with\ntwo flavors of Wilson fermions, concentrating on large values of the hopping\nparameter. Numerous phases are expected, including the conventional confinement\nand deconfinement phases, as well as an Aoki phase with spontaneous breaking of\nflavor and parity and a large hopping phase corresponding to negative quark\nmasses."
    },
    {
        "anchor": "Non-perturbatively Renormalized Light-Quark Masses with the Alpha Action: We have computed the light quark masses using the O(a^2) improved Alpha\naction, in the quenched approximation. The renormalized masses have been\nobtained non-perturbatively. By eliminating the systematic error coming from\nthe truncation of the perturbative series, our procedure removes the\ndiscrepancies, observed in previous calculations, between the results obtained\nusing the vector and the axial-vector Ward identities. It also gives values of\nthe quark masses larger than those obtained by computing the renormalization\nconstants using (boosted) perturbation theory. Our main results, in the RI\n(MOM) scheme and at a renormalization scale \\mu=2 GeV, are m^{RI}_s= 138(15)\nMeV and m^{RI}_l= 5.6(5) MeV, where m^{RI}_s is the mass of the strange quark\nand m^{RI}_l=(m^{RI}_u+m^{RI}_d)/2 the average mass of the up-down quarks. From\nthese results, which have been obtained non-perturbatively, by using continuum\nperturbation theory we derive the \\bar{MS} masses, at the same scale, and the\nrenormalization group invariant (m^{RGI}) masses. We find m^{NLO \\bar{MS}}_s=\n121(13)$ MeV and m^{NLO\\bar{MS}}_l= 4.9(4) MeV at the next-to-leading order;\nm^{N^2LO \\bar{MS}}_s= 111(12) MeV, m^{N^2LO \\bar{MS}}_l= 4.5(4) MeV, m_s^{RGI}=\n177(19) MeV and m^{RGI}_l= 7.2(6) MeV at the next-to-next-to-leading order.",
        "positive": "Eight light flavors on large lattice volumes: I present first results from large-scale lattice investigations of SU(3)\ngauge theory with eight light flavors in the fundamental representation. Using\nleadership computing resources at Argonne, we are generating gauge\nconfigurations with lattice volumes up to $64^3\\times128$ at relatively strong\ncoupling, in an attempt to access the chiral regime. We use nHYP-improved\nstaggered fermions, carefully monitoring finite-volume effects and other\nsystematics. Here I focus on analyses of the light hadron spectrum and chiral\ncondensate, measured on lattice volumes up to $48^3\\times96$ with fermion\nmasses as light as m=0.004 in lattice units. We find no clear indication of\nspontaneous chiral symmetry breaking in these observables. I discuss the\nimplications of these initial results, and prospects for further physics\nprojects employing these ensembles of gauge configurations."
    },
    {
        "anchor": "Perturbative calculation of O(a) improvement coefficients: We compute several coefficients needed for O(a) improvement of currents in\nperturbation theory, using the Brodsky-Lepage-Mackenzie prescription for\nchoosing an optimal scale q*. We then compare the results to non-perturbative\ncalculations. Normalization factors of the vector and axial vector currents\nshow good agreement, especially when allowing for small two-loop effects. On\nthe other hand, there are large discrepancies in the coefficients of O(a)\nimprovement terms. We suspect that they arise primarily from power corrections\ninherent in the non-perturbative methods.",
        "positive": "How to Accurately Extract the Running Coupling of QCD from Lattice\n  Potential Data: By (a) using an expression for the LATTICE potential of QCD in terms of a\nCONTINUUM running coupling and (b) globally parameterizing this coupling to\ninterpolate between 2- (or higher-) loop QCD in the UV and the flux tube\nprediction in the IR, we can perfectly fit lattice data for the potential down\nto ONE lattice spacing and at the same time extract the running coupling to\nhigh precision. This allows us to quantitatively check the accuracy of 2-loop\nevolution, compare with the Lepage-Mackenzie estimate of the coupling extracted\nfrom the plaquette, and determine the scale $r_0$ ten times more accurately\nthan previously possible. For pure SU(3) we find that the coupling scales on\nthe percent level for $\\beta \\geq 6$."
    },
    {
        "anchor": "Multi-Grid Monte Carlo. IV. One-Dimensional $O(4)$-Symmetric Nonlinear\n  $\u03c3$-Model: We study the dynamic critical behavior of the multi-grid Monte Carlo (MGMC)\nalgorithm with piecewise-constant interpolation and a W-cycle, applied to the\none-dimensional $O(4)$-symmetric nonlinear $\\sigma$-model [= $SU(2)$ principal\nchiral model], on lattices from $L=128$ to $L=16384$. Our data for the\nintegrated autocorrelation time $\\tau_{int,{\\cal M}^2}$ are well fit by a\nlogarithmic growth. We have no idea why the critical slowing-down is not\ncompletely eliminated.",
        "positive": "Formal Developments for Lattice QCD with Applications to Hadronic\n  Systems: Lattice quantum chromodynamics (QCD) will soon become the primary theoretical\ntool in rigorous studies of single- and multi-hadron sectors of QCD. It is\ntruly ab initio meaning that its only parameters are those of standard model.\nThe result of a lattice QCD calculation corresponds to that of nature only in\nthe limit when the volume of spacetime is taken to infinity and the spacing\nbetween discretized points on the lattice is taken to zero. A better\nunderstanding of these discretization and volume effects not only provides the\nconnection to the infinite-volume continuum observables, but also leads to\noptimized calculations that can be performed with available computational\nresources. This thesis includes various formal developments in this direction,\nalong with proposals for improvements, to be applied to the upcoming lattice\nQCD studies of nuclear and hadronic systems. Among these developments are i) an\nanalytical investigation of the recovery of rotational symmetry with the use of\nsuitably-formed smeared operators toward the continuum limit, ii) an extension\nof the Luscher finite-volume method to two-nucleon systems with arbitrary\nangular momentum, spin, parity and center of mass momentum, iii) the\napplication of such formalism in extracting the scattering parameters of the\n3S1-3D1 coupled channels, iv) an investigation of twisted boundary conditions\nin the single- and two-hadron sectors, with proposals for improving the\nvolume-dependence of the deuteron binding energy upon proper choices of\nboundary conditions, and v) exploring the volume dependence of the masses of\nhadrons and light-nuclei due to quantum electrodynamic interactions, including\nthe effects arising from particles' compositeness. The required background as\nwell as a brief status report of the field pertinent to the discussions in this\nthesis are presented."
    },
    {
        "anchor": "The k=2 string tension in four dimensional SU(N) gauge theories: We calculate the k=2 string tensions in SU(4) and SU(5) gauge theories in 3+1\ndimensions, and compare them to the k=1 fundamental string tensions. We find,\nfrom the continuum extrapolation of our lattice calculations, that\nK(k=2)/K(k=1) = 1.40(8) in the SU(4) gauge theory, and that K(k=2)/K(k=1) =\n1.56(10) in SU(5). We remark upon the way this might constrain the dynamics of\nconfinement and the intriguing implications it might have for the mass spectrum\nof SU(N) gauge theories. We also note that these results agree closely with the\nMQCD-inspired conjecture that the SU(N) string tensions satisfy K(k)/K(1) =\nsin(k.pi/N)/sin(pi/N).",
        "positive": "Sphaleron-Like Processes in a Realistic Heat Bath: We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional\nAbelian Higgs model interacting with a realistic heat bath for temperatures\nbetween 1/13 and 2/3 times the sphaleron energy. It is found that the measured\nrate is close to that predicted by the sphaleron approximation at the lower end\nof the temperature range considered but falls at least an order of magnitude\nshort of the sphaleron estimate at the upper end of that range. We show\nnumerically that the sphaleron approximation breaks down as soon as the\ngauge-invariant two-point function yields correlation length close to the\nsphaleron size."
    },
    {
        "anchor": "Power corrections from decoupling of the charm quark: Decoupling of heavy quarks at low energies can be described by means of an\neffective theory as shown by S. Weinberg in Ref. [1]. We study the decoupling\nof the charm quark by lattice simulations. We simulate a model, QCD with two\ndegenerate charm quarks. In this case the leading order term in the effective\ntheory is a pure gauge theory. The higher order terms are proportional to\ninverse powers of the charm quark mass $M$ starting at $M^{-2}$. Ratios of\nhadronic scales are equal to their value in the pure gauge theory up to power\ncorrections. We show, by precise measurements of ratios of scales defined from\nthe Wilson flow, that these corrections are very small and that they can be\ndescribed by a term proportional to $M^{-2}$ down to masses in the region of\nthe charm quark mass.",
        "positive": "Current status of $\\varepsilon_K$ with lattice QCD inputs: We present the Standard Model evaluation of the indirect CP violation\nparameter $\\varepsilon_K$ using inputs determined from lattice QCD together\nwith experiment: $|V_{us}|$, $|V_{cb}|$, $\\xi_0$, and $\\hat{B}_K$. We use the\nWolfenstein parametrization ($|V_{cb}|$, $\\lambda$, $\\bar{\\rho}$, $\\bar{\\eta}$)\nfor the CKM matrix elements. For the central value, we take the angle-only fit\nof the UTfit collaboration, and use $|V_{us}|$ from the $K_{\\ell 3}$ and\n$K_{\\mu 2}$ decays as an independent input to fix $\\lambda$. For the error\nestimate, we use results of the global unitarity triangle fits from the\nCKMfitter and UTfit collaborations. We find that the Standard Model (SM)\nprediction of $\\varepsilon_K$ with exclusive $V_{cb}$ (lattice QCD results) is\nlower than the experimental value by $3.6(2)\\sigma$. However, with inclusive\n$V_{cb}$ (results of the heavy quark expansion), the tension between the SM\nprediction of $\\varepsilon_K$ and its experimental value disappears."
    },
    {
        "anchor": "Topology and chiral symmetry breaking in SU(N) gauge theories: We study the low-lying eigenmodes of the lattice overlap Dirac operator for\nSU(N) gauge theories with N=2,3,4 and 5 colours. We define a fermionic\ntopological charge from the zero-modes of this operator and show that, as N\ngrows, any disagreement with the topological charge obtained by cooling the\nfields, becomes rapidly less likely. By examining the fields where there is a\ndisagreement, we are able to show that the Dirac operator does not resolve\ninstantons below a critical size of about rho = 2.5 a, but resolves the larger,\nmore physical instantons. We investigate the local chirality of the near-zero\nmodes and how it changes as we go to larger N. We observe that the local\nchirality of these modes, which is prominent for SU(2) and SU(3), becomes\nrapidly weaker for larger N and is consistent with disappearing entirely in the\nlimit of N -> infinity. We find that this is not due to the observed\ndisappearance of small instantons at larger N.",
        "positive": "Lattice QCD on new chips: a community summary: I review the most recent evolutions of the QCD codes on new architectures,\nwith a focus on the performances obtained by the different coding strategies as\npresented during the Lattice2017 conference."
    },
    {
        "anchor": "Real photon emissions in leptonic decays: We present a non-perturbative calculation of the form factors which\ncontribute to the amplitudes for the radiative decays $P\\to \\ell \\bar \\nu_\\ell\n\\gamma$, where $P$ is a pseudoscalar meson and $\\ell$ is a charged lepton.\nTogether with the non-perturbative determination of the virtual photon\ncorrections to the processes $P\\to \\ell \\bar \\nu_\\ell$, this will allow\naccurate predictions to be made at $O(\\alpha_{em})$ for leptonic decay rates\nfor pseudoscalar mesons ranging from the pion to the $B$ meson. We are able to\nseparate unambiguously the point-like contribution, the square of which leads\nto the infrared divergence in the decay rate, from the structure dependent,\ninfrared-safe, terms in the amplitude. The fully non-perturbative, $O(a)$\nimproved calculation of the inclusive leptonic decay rates will lead to\nsignificantly improved precision in the determination of the corresponding\nCabibbo-Kobayashi-Maskawa (CKM) matrix elements. Precise predictions for the\nemission of a hard photon are also very interesting, especially for the decays\nof heavy $D$ and $B$ mesons for which currently only model-dependent\npredictions are available to compare with existing experimental data.",
        "positive": "Polyakov loop renormalization with gradient flow: We propose to use the gradient flow for the renormalization of Polyakov loops\nin various representations. We study Polyakov loops in 2+1 flavor QCD using the\nHISQ action and lattices with temporal extents $N_\\tau$=6, 8, 10 and 12 in\nvarious representations, including fundamental, sextet, adjoint, decuplet,\n15-plet and 27-plet. This alternative renormalization procedure allows for the\nrenormalization over a large temperature range from $T$=100 MeV - 800 MeV, with\nsmall errors not only for the fundamental, but also for the higher\nrepresentations of the Polyakov loop. We discuss the results of this procedure\nand Casimir scaling of the Polyakov loop."
    },
    {
        "anchor": "Quenched Staggered Spectrum at Beta=6.0, 6.2 and 6.4: We give a preliminary report on the hadron spectrum on an ensemble of\nquenched lattices at $\\beta$ values of 6.0, 6.2 and 6.4, using staggered\nfermions and collaborators Rajan Gupta and Steve Sharpe. Because of the\nrelatively small number of configurations we pay marginally more attention to\nthe question of statistics than in previous analyses. We are unable to\ndiscredit quenched QCD.",
        "positive": "Reducing Chiral Symmetry Violations in Lattice QCD with Domain-Wall\n  Fermions: The inverse of the fermion matrix squared is used to define a transfer matrix\nfor domain-wall fermions. When the domain-wall height $M$ is bigger than one,\nthe transfer matrix is complex. Slowly suppressed chiral symmetry violations\nmay then arise from all eigenvalues of the transfer matrix which are located\nnear the unit circle. Using a variable lattice spacing for the fifth coordinate\nwe enforce the strict positivity of the transfer matrix for any $M$. We\nfurthermore propose a modified pseudo-fermion action, aimed to decrease the\ndensity of close-to-unity eigenvalues of the (positive) transfer matrix, at the\nprice of a small renormalization of the coupling constant. We explain why these\nchanges may reduce chiral symmetry violations in lattice QCD simulations."
    },
    {
        "anchor": "Universal Properties of Chiral Simmetry Breaking: We discuss chiral symmetry breaking critical points from the perspective of\nPCAC, correlation length scaling and the chiral equation of state. A scaling\ntheory for the ratio $R_\\pi$ of the pion to sigma masses is presented. The\nGoldstone character of the pion and properties of the longitudinal and\ntransverse chiral susceptibilities determine the ratio $R_\\pi$ which can be\nused to locate critical points and measure critical indices such as $\\delta$.\nWe show how PCAC and correlation length scaling determine the pion mass'\ndependence on the chiral condensate and lead to a practical method to measure\nthe anomalous dimension $\\eta$. These tools are proving useful in studies of\nthe chiral transition in lattice QED and the quark-gluon plasma transition in\nlattice QCD.",
        "positive": "Random Walks and the Correlation Length Critical Exponent in Scalar\n  Quantum Field Theory: The distance scale for a quantum field theory is the correlation length\n$\\xi$, which diverges with exponent $\\nu$ as the bare mass approaches a\ncritical value. If $t=m^{2}-m_{c}^{2}$, then $\\xi=m_{P}^{-1} \\sim t^{-\\nu}$ as\n$t \\to 0$. The two-point function of a scalar field has a random walk\nrepresentation. The walk takes place in a background of fluctuations (closed\nwalks) of the field itself. We describe the connection between properties of\nthe walk and of the two-point function. Using the known behavior of the two\npoint function, we deduce that the dimension of the walk is $d_{w}=\\phi / \\nu$\nand that there is a singular relation between $t$ and the energy per unit\nlength of the walk $\\theta \\sim t^{\\phi}$ that is due to the singular behavior\nof the background at $t=0$. ($\\phi$ is a computable crossover exponent.)"
    },
    {
        "anchor": "Results for the Etaprime Mass from Two-Flavor Lattice QCD: We present results for the mass of the etaprime meson for two-flavor lattice\nQCD in the continuum limit, calculated on the CP-PACS computer, using an\nRG-improved gauge action and clover fermion action with tadpole-improved csw.\nMeasurements are made at three couplings corresponding to a approx. 0.22, 0.16,\n0.11 fm for four quark masses corresponding to mpi over mrho approx. 0.8, 0.75,\n0.7, 0.6. Thw two-loop diagrams are evaluated using a noisy source method.\nQuark smearing for both one- and two- loop diagrams is successfully applied to\nobtain ground state signals in the etaprime channel. We obtain\nmetaprime=0.960(87)+0.036-0.286GeV in the continuum limit, where the second\nerror represents the systematic uncertainty coming from varying the functional\nform for chiral and continuum extrapolations.",
        "positive": "Heavy-quark free energy at finite temperature with 2+1 flavors of\n  improved Wilson quarks in fixed scale approach: The free energy between a static quark and an antiquark is studied by using\nthe color-singlet Polyakov-line correlation at finite temperature. We perform\nsimulations on $32^3 \\times 12$, 10, 8, 6, 4 lattices in the high temperature\nphase with the RG-improved gluon action and 2+1 flavors of the clover-improved\nWilson quark action. Since the simulations are based on the fixed scale\napproach that the temperature can be varied without changing the spatial volume\nand renormalization factor, it is possible to investigate temperature\ndependence of the heavy-quark free energy without any adjustment of the overall\nconstant. We find that, the heavy-quark free energies at short distance\nconverge to the heavy-quark potential evaluated from the Wilson-loop operator\nat zero temperature, in accordance with the expected insensitivity of short\ndistance physics to the temperature. At long distance, the heavy-quark free\nenergies approach to twice the single-quark free energies, implying that the\ninteraction between heavy quarks is screened. The Debye screening mass obtained\nfrom the long range behavior of the heavy-quark free energy is compared with\nresults of the thermal perturbation theory and those of $N_f=2$ and $N_f=0$\nlattice simulations."
    },
    {
        "anchor": "Tetraquark channels with $\\bar b b$ pair in the static limit: Belle experiment discovered two hadrons with exotic quark content\n$Z_b^+\\simeq \\bar bb \\bar du$. We present a lattice study of the $\\bar bb\\bar\ndu$ systems with various quantum numbers using static bottom quarks. Only one\nset of quantum numbers that couples to $Z_b$ and $\\Upsilon\\;\\pi$ was explored\non the lattice before: these studies found an attractive potential between $B$\nand $\\bar B^*$ which leads to a bound state below the threshold. In the present\nstudy, we consider the other three sets of quantum numbers. Eigen-energies of\nthe $\\bar bb \\bar du$ system are extracted as a function of separation between\n$b$ and $\\bar b$. The resulting eigen-energies do not show any sizable\ndeviation from non-interacting energies of the systems $\\bar bb+\\bar du$ and\n$\\bar bu+\\bar db$, so no significant attraction or repulsion is found. A slight\nexception is a small attraction between $B$ and $\\bar B^*$ at small distance\nfor the quantum number that couples to $Z_b$ and $\\eta_b\\;\\rho$.",
        "positive": "Finite temperature phase transition with two flavors of improved Wilson\n  fermions: The critical temperature is computed for N_f = 2 dynamical flavors of\nnonperturbatively improved Wilson fermions. The new simulations are performed\non lattices 40^3 x 14 with lattice spacing and pion mass about 0.08 fm and 200\nMeV, respectively. We find the deconfinement and chiral phase transitions to\ncoincide within numerical precision. Our results are in broad agreement with a\nsecond order phase transition in the chiral limit. The critical temperature at\nthe physical quark mass is found to be T_c = 172(3)(6) MeV."
    },
    {
        "anchor": "An interquark potential model for multi-quark systems: A potential model for four interacting quarks is constructed in SU(2) from\nsix basis states -- the three partitions into quark pairs, where the gluon\nfield is either in its ground state or first excited state. With four\nindependent parameters to describe the interactions connecting these basis\nstates, it is possible to fit 100 pieces of data -- the ground and first\nexcited states of configurations from six different four-quark geometries\ncalculated on a 16^3*32 lattice.",
        "positive": "Progresses on high-temperature QCD: Equation of State and\n  energy-momentum tensor: We present first non-perturbative results for the renormalization constants\nof the QCD energy-momentum tensor, based on the framework of thermal QCD with\nshifted and twisted (for quarks only) boundary conditions in the compact\ndirection. We also show preliminary results for the entropy density obtained\nwith the very same numerical strategy. This opens the way to the determination\nof the QCD Equation of State up to very high temperatures."
    },
    {
        "anchor": "Leptonic Decays of $B$- and $D$-Mesons: The present status of lattice calculations of $f_D$, $f_B$ and some mass\nsplittings are discussed. When one includes the uncertainties due to\ndiscretization errors, the results do not yet have a sufficient precision to be\nrelevant to phenomenological applications. There are, however, good prospects\nof cutting down the uncertainties by a factor of 2 or more soon.",
        "positive": "Eigenvalue Density of the non-Hermitian Wilson Dirac Operator: We find the lattice spacing dependence of the eigenvalue density of the\nnon-Hermitian Wilson Dirac operator in the $\\epsilon$-domain. The starting\npoint is the joint probability density of the corresponding random matrix\ntheory. In addition to the density of the complex eigenvalues we also obtain\nthe density of the real eigenvalues separately for positive and negative\nchiralities as well as an explicit analytical expression for the number of\nadditional real modes."
    },
    {
        "anchor": "Fixed point actions and on-shell tree-level Symanzik improvement: In this paper it is argued that the properties of the fixed point action of a\nrenormalization group transformation can be used to implement the on-shell\ntree-level Symanzik improvement of lattice actions to any given order in the\nexpansion in the lattice spacing, in a way which does not involve any\nperturbative calculations. In particular, a well-known technique for the lowest\norder improvement of SU(N) lattice gauge theories is revisited from the point\nof view of fixed point actions, which allows to shed light on some subtle\npoints.",
        "positive": "Asymptotic Scaling and Infrared Behavior of the Gluon Propagator: The Landau gauge gluon propagator for the pure gauge theory is evaluated on a\n32^3x64 lattice with a physical volume of (3.35^3x6.7)fm^4. Comparison with two\nsmaller lattices at different lattice spacings allows an assessment of finite\nvolume and finite lattice spacing errors. Cuts on the data are imposed to\nminimize these errors. Scaling of the gluon propagator is verified between\nbeta=6.0 and beta=6.2. The tensor structure is evaluated and found to be in\ngood agreement with the Landau gauge form, except at very small momentum\nvalues, where some small finite volume errors persist. A number of functional\nforms for the momentum dependence of the propagator are investigated. The form\nD(q^2)=D_ir+D_uv, where D_ir(q^2) ~ (q^2+M^2)^-\\eta and D_uv is an infrared\nregulated one-loop asymptotic form, is found to provide an adequate description\nof the data over the entire momentum region studied - thereby bridging the gap\nbetween the infrared confinement region and the ultraviolet asymptotic region.\nThe best estimate for the exponent \\eta is 3.2(+0.1/-0.2)(+0.2/-0.3), where the\nfirst set of errors represents the uncertainty associated with varying the\nfitting range, while the second set of errors reflects the variation arising\nfrom different choices of infrared regulator in D_uv. Fixing the form of D_uv,\nwe find that the mass parameter M is (1020+/-100)MeV."
    },
    {
        "anchor": "Baryonic states in $\\mathbf{\\mathcal{N}=1}$ supersymmetric SU(2)\n  Yang-Mills theory on the lattice: We extend our analysis of bound states in $\\mathcal{N}=1$ supersymmetric\nYang-Mills theory by the consideration of baryonic operators, which are\ncomposed of three gluino fields. The corresponding states are similar to the\nbaryons in QCD, but due to the difference between gluino and quark fields,\ntheir properties and the fermion line contractions involved in their\ncorrelation functions are different from QCD. In this work, we first explain\nthe derivation of these operators and the contractions needed in numerical\ncalculations of their correlators. In contrast to QCD the correlators contain a\nspectacle piece, which requires methods for all-to-all propagators. We provide\na first estimate of the two-point function and the mass of the lightest\nbaryonic state in $\\mathcal{N}=1$ supersymmetric Yang-Mills theory.",
        "positive": "Light hadrons with improved staggered quarks: approaching the continuum\n  limit: We have extended our program of QCD simulations with an improved\nKogut-Susskind quark action to a smaller lattice spacing, approximately 0.09\nfm. Also, the simulations with a approximately 0.12 fm have been extended to\nsmaller quark masses. In this paper we describe the new simulations and\ncomputations of the static quark potential and light hadron spectrum. These\nresults give information about the remaining dependences on the lattice\nspacing. We examine the dependence of computed quantities on the spatial size\nof the lattice, on the numerical precision in the computations, and on the step\nsize used in the numerical integrations. We examine the effects of\nautocorrelations in \"simulation time\" on the potential and spectrum. We see\neffects of decays, or coupling to two-meson states, in the 0++, 1+, and 0-\nmeson propagators, and we make a preliminary mass computation for a radially\nexcited 0- meson."
    },
    {
        "anchor": "Dynamical Fermions in Hamiltonian Lattice Gauge Theory: We describe a first attempt to understand dynamical fermions within a\nHamiltonian framework. As a testing ground we study compact QED3 which shares\nsome important features of QCD4 such as confinement, glueballs, mesons, and\nchiral symmetry breaking. We discuss the methods used and show data for the\nchiral condensate.",
        "positive": "Determination of $B_K$ using improved staggered fermions (III) Finite\n  volume effects: We study the finite-volume effects in our calculation of $B_K$ using\nHYP-smeared improved staggered valence fermions. We calculate the predictions\nof both SU(3) and SU(2) staggered chiral perturbation theory at one-loop order.\nWe compare these to the results of a direct calculation, using MILC coarse\nlattices with two different volumes: $20^3$ and $28^3$. From the direct\ncalculation, we find that the finite volume effect is $\\approx 2%$ for the\nSU(3) analysis and $\\approx 0.9%$ for the SU(2) analysis. We also show how the\nstatistical error depends on the number of measurements made per configuration,\nand make a first study of autocorrelations."
    },
    {
        "anchor": "Radiative Transitions in Charmonium from Lattice QCD: The coupling of various charmonium mesons to a photon is studied using\nlattice QCD, giving access to radiative form factors and transitions, and\nprobing the mesons' structure. Methods are developed which allow the robust\ndetermination of amplitudes, including those involving an excited state as well\nas multiple form factors, for a range of kinematics. These are applied in\ndynamical lattice QCD calculations using the distillation technique to compute\nthe underlying three-point correlation functions. Form factors and amplitudes\ninvolving the low-lying charmonia, $\\eta_c$, $J/\\psi$, $\\chi_{c0}$ and\n$\\eta_c'$, are calculated, demonstrating the methods and providing the first\ndynamical lattice QCD results for some quantities.",
        "positive": "Adjoint quarks and fermionic boundary conditions: We study quenched SU(2) lattice gauge theory with adjoint fermions in a wide\nrange of temperatures. We focus on spectral quantities of the Dirac operator\nand use the temporal fermionic boundary conditions as a tool to probe the\nsystem. We determine the deconfinement temperature through the Polyakov loop,\nand the chiral symmetry restoration temperature for adjoint fermions through\nthe gap in the Dirac spectrum. This chiral transition temperature is about four\ntimes larger than the deconfinement temperature. In between the two transitions\nwe find that the system is characterized by a non-vanishing chiral condensate\nwhich differs for periodic and anti-periodic fermion boundary conditions. Only\nfor the latter (physical) boundary conditions, the condensate vanishes at the\nchiral transition. The behavior between the two transitions suggests that\ndeconfinement manifests itself as the onset of a dependence of spectral\nquantities of the Dirac operator on boundary conditions. This picture is\nsupported further by our results for the dual chiral condensate."
    },
    {
        "anchor": "Lattice QCD studies on decuplet baryons as meson-baryon bound states in\n  the HAL QCD method: We study decuplet baryons from meson-baryon interactions in lattice QCD, in\nparticular, $\\Delta$ and $\\Omega$ baryons from P-wave $I=3/2$ $N\\pi$ and $I=0$\n$\\Xi\\bar{K}$ interactions, respectively. Interaction potentials are calculated\nin the HAL QCD method using 3-quark-type source operators at $m_{\\pi} \\approx\n410~\\textrm{MeV}$ and $m_{K} \\approx 635~\\textrm{MeV}$, where $\\Delta$ as well\nas $\\Omega$ baryons are stable. We use the conventional stochastic estimate of\nall-to-all propagators combined with the all-mode averaging to reduce\nstatistical fluctuations. We have found that the $\\Xi\\bar K$ system has a\nweaker attraction than the $N\\pi$ system while the binding energy from the\nthreshold is larger for $\\Omega$ than $\\Delta$. This suggests that an\ninequality $m_{N}+m_{\\pi}-m_{\\Delta}<m_{\\Xi}+m_{\\bar K}-m_{\\Omega}$ comes\nmainly from a smaller spatial size of a $\\Xi \\bar K$ bound state due to a\nlarger reduced mass, rather than its interaction. Root-mean-square distances of\nbound states in both systems are small, indicating that $\\Delta$ and $\\Omega$\nare tightly bound states and thus can be regarded qualitatively as composite\nstates of 3 quarks. Results of binding energies agree with those obtained from\ntemporal 2-point functions within large systematic errors, which arise\ndominantly from the lattice artifact at short distances.",
        "positive": "A comparison of updating algorithms for large N reduced models: We investigate Monte Carlo updating algorithms for simulating $SU(N)$\nYang-Mills fields on a single-site lattice, such as for the Twisted\nEguchi-Kawai model (TEK). We show that performing only over-relaxation (OR)\nupdates of the gauge links is a valid simulation algorithm for the Fabricius\nand Haan formulation of this model, and that this decorrelates observables\nfaster than using heat-bath updates. We consider two different methods of\nimplementing the OR update: either updating the whole $SU(N)$ matrix at once,\nor iterating through $SU(2)$ subgroups of the $SU(N)$ matrix, we find the same\ncritical exponent in both cases, and only a slight difference between the two."
    },
    {
        "anchor": "The quark mass and $\u03bc$ dependence of the QCD chiral critical point: In order to study the QCD chiral critical point we investigate Binder\nCumulants of the chiral condensate. The results were obtained from simulations\nof 3 and 2+1 flavors of standard staggered fermions and 3 flavors of p4\nimproved staggered fermions. The quark masses used are close to the physical\nquark mass. To extract the dependence on quark mass and chemical potential we\napply a new reweighting technique based on a Taylor expansion of the action.\nThe reweighting accuracy is ${\\cal O}(m)$ for the standard and ${\\cal O}(m^2)$,\n${\\cal O}(\\mu^2)$ for the p4 action.",
        "positive": "Thermodynamics of SU(3) Gauge Theory in 2 + 1 Dimensions: The pressure, and the energy and entropy densities are determined for the\nSU(3) gauge theory in $2 + 1$ dimensions from lattice Monte Carlo calculations\nin the interval $0.6 \\leq T/T_c \\leq 15$. The finite temperature lattices\nsimulated have temporal extent $N_\\tau = 2, 4, 6$ and 8, and spatial volumes\n$N_S^2$ such that the aspect ratio is $N_S/N_\\tau = 8$. To obtain the\nthermodynamical quantities, we calculate the averages of the temporal\nplaquettes $P_\\tau$ and the spatial plaquettes $P_S$ on these lattices. We also\nneed the zero temperature averages of the plaquettes $P_0$, calculated on\nsymmetric lattices with $N_\\tau = N_S$. We discuss in detail the finite size\n($N_S$-dependent) effects. These disappear exponentially. For the zero\ntemperature lattices we find that the coefficient of $N_S$ in the exponent is\nof the order of the glueball mass. On the finite temperature lattices it lies\nbetween the two lowest screening masses. For the aspect ratio equal to eight,\nthe systematic errors coming from the finite size effects are much smaller than\nour statistical errors. We argue that in the continuum limit, at high enough\ntemperature, the pressure can be parametrized by the very simple formula\n$p=a-bT_c/T$ where $a$ and $b$ are two constants. Using the thermodynamical\nidentities for a large homogeneous system, this parametrization then determines\nthe other thermodynamical variables in the same temperature range."
    },
    {
        "anchor": "Two dimensional twisted chiral fermions on the lattice: It is shown that the lattice overlap correctly reproduces the chiral\ndeterminant on a two dimensional torus in the presence of nontrivial background\nPolyakov loop variables.",
        "positive": "Wess-Zumino term by Vacuum Overlap Formula: We examine the vacuum overlap formula for the two-dimensional SU(2)\nWess-Zumino term in lattice regularization. Perturbatively it reproduces the\nWess-Zumino term correctly in the continuum limit and yields the IR fixed point\nin the beta function of the chiral model. Nonperturbatively it shows a sharp\nGaussian distribution for the SU(2) chiral field configurations in the scaling\nregion, where smooth configurations dominate even in the symmetric phase due to\nasymptotic freedom. Crossover is sharp from the strong coupling region where\nthe Wess-Zumino term fluctuates hard and the species doublers' contribution is\nsuspected to affect it."
    },
    {
        "anchor": "Non-perturbative running of the coupling from four flavour lattice QCD\n  with staggered quarks: Using the Schr\\\"odinger functional (SF) with a single staggered fermion field\nwe calculate the SF coupling in four-flavour QCD for a wide range of energies\nand lattice sizes up to $L/a=16$. Preliminary results for the continuum\nextrapolation of the step-scaling function are presented. To reduce cutoff\neffects, one-loop ${\\rm O}(a)$ improvement has been implemented. Various cross\nchecks are made possible by the use of two independent sets of lattices with\neither $T=L+a$ or $T=L-a$.",
        "positive": "Topological transitions in the euclidean 2d U(1)-Higgs model: The two-dimensional U(1)-gauged Higgs model is studied on an euclidean\nlattice of size $L_1\\times L_2$, where the temperature $T=L_2^{-1}$ is of the\norder of the sphaleron mass. The simulation parameters are taken from zero\ntemperature results. By comparison with classical and semiclassical results I\ndiscuss, whether the sphaleron transition rate can be extracted from the\nbehavior of the Chern-Simons number and from the formation of vortices in an\neuclidean simulation at high temperatures."
    },
    {
        "anchor": "Local chiral fermions: Borici's construction of minimally doubled chiral fermions builds on a linear\ncombination of two unitarily related naive fermion actions. Being strictly\nlocal, extremely efficient numerical implementation should be possible. The\nresulting system is symmetric under the subgroup of the hypercubic group that\npreserves a major hypercube diagonal. The symmetry includes both parity even\nand odd transformations, but allows for an anisotropy to appear at finite\nlattice spacing.",
        "positive": "Baryons in 2+1 flavour domain wall QCD: We present results for some of the light baryon masses and their excited\nstates in 2+1 flavour domain wall QCD. We considered several lattice spacings,\nwith the DBW2 and Iwasaki gauge actions and different sea quark masses on a\nvolume of $16^3\\times32$ and a fifth dimension of size 8. All data were\ngenerated on the QCDOC machines. Despite large residual massses and a limited\nnumber of sea quark mass values with which to perform chiral extrapolations,\nour results are in reasonable agreement with experiment and scale within\nerrors. Finite size effects on most ensembles appear to be small."
    },
    {
        "anchor": "Unification of the complex Langevin method and the Lefschetz-thimble\n  method: Recently there has been remarkable progress in solving the sign problem,\nwhich occurs in investigating statistical systems with a complex weight. The\ntwo promising methods, the complex Langevin method and the Lefschetz thimble\nmethod, share the idea of complexifying the dynamical variables, but their\nrelationship has not been clear. Here we propose a unified formulation, in\nwhich the sign problem is taken care of by both the Langevin dynamics and the\nholomorphic gradient flow. We apply our formulation to a simple model in three\ndifferent ways and show that one of them interpolates the two methods by\nchanging the flow time.",
        "positive": "Simulation of dynamical fermions with smeared links: Smearing the gauge links of dynamical configurations removes small scale\nunphysical vacuum fluctuations und thus improves the chiral properties of\nlattice fermions. We present a new algorithm for the simulation of dynamical\nfermions coupled via smeared links based on the standard pure gauge\noverrelaxation and heatbath updatings. Smeared links play a fundamental role in\nmaking this algorithm effective. At fixed lattice spacing the computational\ncost of the algorithm has an extra volume factor due to the finite volume of\nthe lattice region which can be updated. As the continuum limit is approached\nthe physical volume of the updated region remains constant. We simulated four\nflavors of staggered fermions coupled via hypercubic (HYP) smeared links. The\nsimulation cost of the new algorithm on 10 fm^4 volumes is a factor 2-8 larger\nthan with the standard Hybrid Monte Carlo but the improved properties of the\nHYP action allow to gain a factor 2 in the lattice spacing. The new algorithm\ncould be applicable to simulations of more complicated chiral fermionic\nactions, like overlap or perfect actions."
    },
    {
        "anchor": "Monopole fields from vortex sheets reconciling Abelian and center\n  dominance: We describe a new order parameter for the confinement-deconfinement\ntransition in lattice SU(2) Yang-Mills theory. It is expressed in terms of\nmagnetic monopole field correlators represented as sums over sheets of center\nvortices. Our construction establishes a link between \"abelian\" and \"center\ndominance\". It avoids an inconsistency in the treatment of small scales present\nin earlier definitions of monopole fields by respecting Dirac's quantization\ncondition for magnetic fluxes.",
        "positive": "SU(2) Lattice Gauge Theory- Local Dynamics on Non-intersecting Electric\n  flux Loops: We use Schwinger Bosons as prepotentials for lattice gauge theory to define\nlocal linking oper- ators and calculate their action on linking states for 2 +\n1 dimensional SU(2) lattice gauge theory. We develop a diagrammatic technique\nand associate a set of (lattice Feynman) rules to compute the entire loop\ndynamics diagrammatically. The physical loop space is shown to contain only\nnon- intersecting loop configurations after solving the Mandelstam constraint.\nThe smallest plaquette loops are contained in the physical loop space and other\nconfigurations are generated by the action of a set of fusion operators on this\nbasic loop states enabling one to charaterize any arbitrary loop by the basic\nplaquette together with the fusion variables. Consequently, the full\nKogut-Susskind Hamiltonian and the dynamics of all possible non-intersecting\nphysical loops are formulated in terms of these fusion variables."
    },
    {
        "anchor": "On the axial $U(1)$ symmetry at finite temperature: We study the $U(1)_A$ anomaly in two-flavor lattice QCD at finite temperature\nwith the M\\\"obius domain-wall Dirac operator. We generate gauge configurations\nin the temperature range $(0.9, 1.2) T_c$ on different physical volumes, $L=$\n2--4 fm, and lattice spacings. We measure the difference of the\nsusceptibilities of the flavor non-singlet scalar ($\\chi_\\delta$) and\npseudoscalar ($\\chi_\\pi$) mesons. They are related by an axial $U(1)$\ntransformation and the difference vanishes if the axial $U(1)$ symmetry is\nrespected. We identify the source of axial $U(1)$ symmetry breaking at finite\ntemperature in the lowest eigenmodes, for the observable $\\chi_\\pi -\n\\chi_\\delta$. We then reweight the M\\\"obius domain-wall fermion partition\nfunction to that of the overlap-Dirac operator to fully recover chiral\nsymmetry. Our data show a significant discrepancy in the results coming from\nthe M\\\"obius domain-wall valence quarks, the overlap valence quarks on our DWF\nconfigurations and the reweighted ones that have full chiral symmetry. After\nrecovering full chiral symmetry we conclude that the difference $\\chi_\\pi -\n\\chi_\\delta$ shows a suppression in the chiral limit that is compatible with an\neffective restoration of $U(1)_A$ at $T \\gtrsim T_c$ in the scalar meson\nchannels.",
        "positive": "Lorentz gauge fixing and lattice QED: The Gribov ambiguity problem is studied for compact lattice QED within the\nLorentz gauge. In the Coulomb phase, Gribov copies are mainly caused by double\nDirac sheets and zero-momentum modes of the gauge fields. Removing them by\n(non-) periodic gauge transformations allows to reach the absolute extremum of\nthe Lorentz gauge functional. For standard Lorentz gauge fixing the Wilson\nfermion correlator turns out to be strongly effected by the zero-momentum\nmodes. A reliable fermion mass estimate requires the proper treatment of these\nmodes."
    },
    {
        "anchor": "Phase transition of four-dimensional lattice $\u03c6^4$ theory with tensor\n  renormalization group: We investigate the phase transition of the four-dimensional single-component\n$\\phi^4$ theory on the lattice using the tensor renormalization group method.\nWe have examined the hopping parameter dependence of the bond energy and the\nvacuum condensation of the scalar field $\\langle\\phi\\rangle$ at a finite\nquartic coupling $\\lambda$ on large volumes up to $V=1024^4$ in order to detect\nthe spontaneous breaking of the $\\mathbb{Z}_2$ symmetry. Our results show that\nthe system undergoes the weak first-order phase transition at a certain\ncritical value of the hopping parameter. We also make a comparative study of\nthe three-dimensional $\\phi^4$ theory and find that the properties of the phase\ntransition are consistent with the universality class of the three-dimensional\nIsing model.",
        "positive": "The sign problem across the QCD phase transition: The average phase factor of the QCD fermion determinant signals the strength\nof the QCD sign problem. We compute the average phase factor as a function of\ntemperature and baryon chemical potential using a two-flavor NJL model. This\nallows us to study the strength of the sign problem at and above the chiral\ntransition. It is discussed how the $U_A(1)$ anomaly affects the sign problem.\nFinally, we study the interplay between the sign problem and the endpoint of\nthe chiral transition."
    },
    {
        "anchor": "Lattice QCD Study of the Pentaquark Baryons: We study the spin $\\frac12$ hadronic state in quenched lattice QCD to search\nfor a possible $S=+1$ pentaquark resonance. Simulations are carried out on\n$8^3\\times 24$, $10^3\\times 24$, $12^3\\times 24$ and $16^3\\times 24$ lattices\nat $\\beta$=5.7 at the quenched level with the standard plaquette gauge action\nand Wilson quark action. We adopt two independent operators with I=0 and\n$J^P=\\frac12$ to construct a $2\\times 2$ correlation matrix. After the\ndiagonalization of the correlation matrix, we successfully obtain the energies\nof the ground-state and the 1st excited-state in this channel. The volume\ndependence of the energies suggests the existence of a possible resonance state\nslightly above the NK threshold in I=0 and $J^P=\\frac12^-$ channel.",
        "positive": "Qubitization strategies for bosonic field theories: Quantum simulations of bosonic field theories require a truncation in field\nspace to map the theory onto finite quantum registers. Ideally, the truncated\ntheory preserves the symmetries of the original model and has a critical point\nin the same universality class. In this paper, we explore two different\ntruncations that preserve the symmetries of the 1+1-dimensional $O(3)$\nnon-linear $\\sigma$-model - one that truncates the Hilbert space for the unit\nsphere by setting an angular momentum cutoff and a fuzzy sphere truncation\ninspired by non-commutative geometry. We compare the spectrum of the truncated\ntheories in a finite box with the full theory. We use open boundary conditions,\na novel method that improves on the correlation lengths accessible in our\ncalculations. We provide evidence that the angular-momentum truncation fails to\nreproduce the $\\sigma$-model and that the anti-ferromagnetic fuzzy model agrees\nwith the full theory."
    },
    {
        "anchor": "Sampling of General Correlators in Worm Algorithm-based Simulations: Using the complex $\\phi^4$-model as a prototype for a system which is\nsimulated by a worm algorithm, we show that not only the charged correlator\n$<\\phi^{*}(x)\\phi(y)>$, but also more general correlators such as\n$<|\\phi(x)||\\phi(y)|>$ or $<\\text{arg}(\\phi(x))\\text{arg}(\\phi(y))>$, as well\nas condensates like $<|\\phi|>$, can be measured at every step of the Monte\nCarlo evolution of the worm instead of on closed-worm configurations only. The\nmethod generalizes straightforwardly to other systems simulated by worms, such\nas spin or sigma models.",
        "positive": "The crossover from first to second-order finite size scaling: A\n  numerical study Christian Borgs: We consider a particular case of the two dimensional\n  Blume-Emery-Griffiths model to study the finite-size scaling for a field\ndriven first-order phase transition with two coexisting phases not related by a\nsymmetry. For low temperatures we verify the asymptotic (large volume)\npredictions of the rigorous theory of Borgs and Kotecky, including the\npredictions concerning the so-called equal-weight versus equal-height\ncontroversy. Near the critical temperature we show that all data fit onto a\nunique curve, even when the correlation length xi becomes comparable to or\nlarger then the size of the system, provided the linear dimension L of the\nsystem is rescaled by xi."
    },
    {
        "anchor": "K pi scattering and the K* decay width from lattice QCD: K* mesons and in particular the K*(892) were frequently addressed in lattice\nsimulations, but always while ignoring that the K*(892) decays strongly. We\npresent an exploratory extraction of the masses and widths for the K*\nresonances by simulating K pi scattering in p-wave with I = 1/2 on the lattice.\nThe K pi system with total momenta P = 2*pi/L e_z, 2*pi/L (e_x + e_y) and 0,\nthat allows the extraction of phase shifts at several values of K pi relative\nmomenta, is studied. A Breit-Wigner fit of the phase renders a K*(892)\nresonance mass m^{lat} = 891 +/- 14 MeV and the K*(892) -> K pi coupling\ng^{lat} = 5.7 +/- 1.6 compared to the experimental values m^{exp} = 892 MeV and\ng^{exp} = 5.72 +/- 0.06, where g parametrizes the K* -> K pi width. When\nextracting the phase shift around the K*(1410) and K2*(1430) resonances we take\ninto account the mixing of p-wave with d-wave and assume that the scattering is\nelastic in our simulation. This gives us an estimate of the K*(1410) resonance\nmass m^{lat} = 1.33 +/- 0.02 GeV compared to m^{exp} = 1.414 +/- 0.0015 GeV\nassuming the experimental K*(1410) -> K pi coupling. We contrast the resonant I\n= 1/2 channel with the repulsive non-resonant I = 3/2 channel, where the phase\nis found to be negative and small, in agreement with experiment.",
        "positive": "Advanced Lattice QCD: The topics covered by the lectures include Symanzik's effective continuum\ntheory, O(a) improvement, chiral symmetry on the lattice and non-perturbative\nrenormalization."
    },
    {
        "anchor": "Laplacian Abelian Projection: Abelian dominance and Monopole dominance: A comparative study of Abelian and Monopole dominance in the Laplacian and\nMaximally Abelian projected gauges is carried out. Clear evidence for both\ntypes of dominance is obtained for the Laplacian projection. Surprisingly, the\nevidence is much more ambiguous in the Maximally Abelian gauge. This is\nattributed to possible ``long-distance imperfections'' in the maximally abelian\ngauge fixing.",
        "positive": "Asymptotics of Fixed Point Distributions for Inexact Monte Carlo\n  Algorithms: We introduce a simple general method for finding the equilibrium distribution\nfor a class of widely used inexact Markov Chain Monte Carlo algorithms. The\nexplicit error due to the non-commutivity of the updating operators when\nnumerically integrating Hamilton's equations can be derived using the\nBaker-Campbell-Hausdorff formula. This error is manifest in the conservation of\na ``shadow'' Hamiltonian that lies close to the desired Hamiltonian. The fixed\npoint distribution of inexact Hybrid algorithms may then be derived taking into\naccount that the fixed point of the momentum heatbath and that of the molecular\ndynamics do not coincide exactly. We perform this derivation for various\ninexact algorithms used for lattice QCD calculations."
    },
    {
        "anchor": "Sign problem and MEM: The sign problem is notorious in Monte\n  Carlo simulations of lattice QCD with the finite density, lattice field\ntheory (LFT) with a $\\theta$ term and quantum spin models. In this report, to\ndeal with the sign problem, we apply the maximum entropy method (MEM) to LFT\nwith the $\\theta$ term and investigate to what extent the\n  MEM is applicable to this issue. Based on this study, we also make a brief\ncomment about lattice QCD with the finite density in terms of the\n  MEM.",
        "positive": "How to compute one-loop Feynman diagrams in lattice QCD with Wilson\n  fermions: We describe an algebraic algorithm which allows to express every one-loop\nlattice integral with gluon or Wilson-fermion propagators in terms of a small\nnumber of basic constants which can be computed with arbitrary high precision.\nAlthough the presentation is restricted to four dimensions the technique can be\ngeneralized to every space dimension. We also give a method to express the\nlattice free propagator for Wilson fermions in coordinate space as a linear\nfunction of its values in eight points near the origin. This is an essential\nstep in order to apply the recent methods of L\\\" uscher and Weisz to\nhigher-loop integrals with fermions."
    },
    {
        "anchor": "Operator product expansion and quark condensate from Lattice QCD in\n  coordinate space: We present a Lattice QCD determination of the chiral quark condensate based\non a new method. We extract the quark condensate from the operator product\nexpansion of the quark propagator at short euclidean distances, where it\nrepresents the leading contribution in the chiral limit. From this study we\nobtain <\\bar q q>^ms(2 GeV)=-(265+-5+-22 MeV)^3$, in good agreement with\ndeterminations of this quantity based on different approaches. The simulation\nis performed by using the O(a)-improved Wilson action at beta=6.45 on a volume\n32^3\\times70 in the quenched approximation.",
        "positive": "From Lattice Strong Dynamics to Phenomenology: We present updated results on the chiral properties of SU(3) gauge theories\nwith 2 and 6 massless Dirac fermions in the fundamental representation. Our\nfocus is on the ratio $\\langle \\bar{\\psi} \\psi \\rangle / F^3$, where $\\langle\n\\bar{\\psi} \\psi \\rangle$ is the chiral condensate and $F$ is the\npseudo-Nambu-Goldstone-boson decay constant. This ratio is of interest in the\ncontext of fermion mass generation within composite Higgs theories. By\nre-expanding certain ratios using next-to-leading-order chiral perturbation\ntheory, we confirm our previous result of significant enhancement of this ratio\nat $N_f = 6$ over $N_f = 2$."
    },
    {
        "anchor": "Strong coupling expansion for scattering phases in hamiltonian lattice\n  field theories - II. SU(2) gauge theory in (2+1) dimensions: A recently proposed method for a strong coupling analysis of scattering\nphenomena in hamiltonian lattice field theories is applied to the $\\SU2$\nYang-Mills model in $(2+1)$ dimensions. The calculation is performed up to\nsecond order in the hopping parameter. All relevant quantities that\ncharacterize the collision between the lightest glueballs in the elastic region\n-- cross section, phase shifts, resonance parameters -- are determined.",
        "positive": "Continuum EoS for QCD with Nf=2+1 flavors: We report on a continuum extrapolated result [arXiv:1309.5258] for the\nequation of state (EoS) of QCD with $N_f=2+1$ dynamical quark flavors. In this\nstudy, all systematics are controlled, quark masses are set to their physical\nvalues, and the continuum limit is taken using at least three lattice spacings\ncorresponding to temporal extents up to $N_t=16$. A Symanzik improved gauge and\nstout-link improved staggered fermion action is used. Our results are available\nonline [ancillary file to arXiv:1309.5258]."
    },
    {
        "anchor": "Mean Field Phase Diagram of SU(2)xSU(2) Lattice Higgs-Yukawa Model at\n  Finite Lambda: The phase diagram of an SU(2)_L x SU(2)_R lattice Higgs-Yukawa model with\nfinite lambda is constructed using mean field theory. The phase diagram bears a\nsuperficial resemblance to that for infinite lambda, however as lambda is\ndecreased the paramagnetic region shrinks in size. For small lambda the phase\ntransitions remain second order, and no new first order transitions are seen.",
        "positive": "Pion form factors in the epsilon regime: We consider how to extract the pion form factors in the epsilon regime. Using\nthe correlators with non-zero momenta and taking appropriate ratios of them, we\neliminate the dominant finite volume effect from the zero-momentum pion mode.\nOur preliminary lattice result for the pion charge radius is consistent with\nthe experiment."
    },
    {
        "anchor": "Complex Langevin for Lattice QCD at $T=0$ and $\u03bc\\ge 0$: QCD at finite quark-/baryon-number density, which describes nuclear matter,\nhas a sign problem which prevents direct application of standard simulation\nmethods based on importance sampling. When such finite density is implemented\nby the introduction of a quark-number chemical potential $\\mu$, this manifests\nitself as a complex fermion determinant. We apply simulations using the Complex\nLangevin Equation (CLE) which can be applied in such cases. However, this is\nnot guaranteed to give correct results, so that extensive tests are required.\nIn addition, gauge cooling is required to prevent runaway behaviour. We test\nthese methods on 2-flavour lattice QCD at zero temperature on a small ($12^4$)\nlattice at an intermediate coupling $\\beta=6/g^2=5.6$ and relatively small\nquark mass $m=0.025$, over a range of $\\mu$ values from $0$ to saturation.\nWhile this appears to show the correct phase structure with a phase transition\nat $\\mu \\approx m_N/3$ and a saturation density of $3$ at large $\\mu$, the\nobservables show departures from known values at small $\\mu$. We are now\nrunning on a larger lattice ($16^4$) at weaker coupling $\\beta=5.7$. At $\\mu=0$\nthis significantly improves agreement between measured observables and known\nvalues, and there is some indication that this continues to small $\\mu$s. This\nleads one to hope that the CLE might produce correct results in the\nweak-coupling -- continuum -- limit.",
        "positive": "Quantum simulation of the universal features of the Polyakov loop: Lattice gauge theories are fundamental to our understanding of high-energy\nphysics. Nevertheless, the search for suitable platforms for their quantum\nsimulation has proven difficult. We show that the Abelian Higgs model in 1+1\ndimensions is a prime candidate for an experimental quantum simulation of a\nlattice gauge theory. To this end, we use a discrete tensor reformulation to\nsmoothly connect the space-time isotropic version used in most numerical\nlattice simulations to the continuous-time limit corresponding to the\nHamiltonian formulation. The eigenstates of the Hamiltonian are neutral for\nperiodic boundary conditions, but we probe the nonzero charge sectors by either\nintroducing a Polyakov loop or an external electric field. In both cases we\nobtain universal functions relating the mass gap, the gauge coupling, and the\nspatial size which are invariant under the deformation of the temporal lattice\nspacing. We propose to use a physical multi-leg ladder of atoms trapped in\noptical lattices and interacting with Rydberg-dressed interactions to quantum\nsimulate the model and check the universal features. Our results provide a path\nto the analog quantum simulation of lattice gauge theories with atoms in\noptical lattices."
    },
    {
        "anchor": "Leptonic decay constants fK, fD and fDs with Nf = 2+1+1 twisted-mass\n  lattice QCD: We present a lattice QCD calculation of the pseudoscalar decay constants fK,\nfD and fDs performed using the gauge configurations produced by the European\nTwisted Mass Collaboration with Nf = 2 + 1 + 1 dynamical quarks, which include\nin the sea, besides two light mass degenerate quarks, also the strange and\ncharm quarks with masses close to their values in the real world. The\nsimulations are based on a unitary setup for the two light mass-degenerate\nquarks and on a mixed action approach for the strange and charm quarks. We use\ndata simulated at three different values of the lattice spacing in the range\n0.06 - 0.09 fm and at pion masses in the range 210 - 450 MeV. Our main results\nare: fK+ / fpi+ = 1.184 (16), fK+ = 154.4 (2.0) MeV, which incorporate the\nleading strong isospin breaking correction due to the up- and down-quark mass\ndifference, and fK = 155.0 (1.9) MeV, fD = 207.4 (3.8) MeV, fDs = 247.2 (4.1)\nMeV, fDs / fD = 1.192 (22) and (fDs / fD) / (fK / fpi) = 1.003 (14) obtained in\nthe isospin symmetric limit of QCD. Combined with the experimental measurements\nof the leptonic decay rates of kaon, pion, D- and Ds-mesons our results lead to\nthe following determination of the CKM matrix elements: |Vus| = 0.2269 (29),\n|Vcd| = 0.2221 (67) and |Vcs| = 1.014 (24). Using the latest value of |Vud|\nfrom superallowed nuclear beta decays the unitarity of the first row of the CKM\nmatrix is fulfilled at the permille level.",
        "positive": "Lattice QCD Calculation of Flavor Singlet Matrix Elements and N-N\n  Scattering Lengths: We report on our recent study of flavor singlet matrix elements calculated\nwith the wall source method without gauge fixing. Results are presented for the\nmass difference between $\\eta^{\\prime}$ and pseudoscalar octet mesons, the\n$\\pi$-N $\\sigma$ term and the proton axial vector matrix elements. An\nexploratory calculation of the N-N scattering lengths is also discussed\nincluding a phenomenological study with one-boson exchange potentials."
    },
    {
        "anchor": "Lattice QCD at nonzero temperature and density: We discuss some selected recent developments in the field of lattice QCD at\nnonzero temperature and density, describing in particular the transition from\nthe hadronic gas to the quark-gluon plasma, as seen in simulations using Wilson\nfermions.",
        "positive": "Matter on granular space-time: We develop further the formalism of the non-Abelian gauge field theory on a\ncell complex space-time and show how the gauge-invariant action and the\nequations of motion for gauge fields interacting with spinors can be written\nwithout a reference to the geometrical nature of the cells of the cell complex.\nThe general results are illustrated with examples of solutions of equations of\nmotion for U(N) and SU(N) gauge groups."
    },
    {
        "anchor": "Domain wall QCD with physical quark masses: We present results for several light hadronic quantities ($f_\\pi$, $f_K$,\n$B_K$, $m_{ud}$, $m_s$, $t_0^{1/2}$, $w_0$) obtained from simulations of 2+1\nflavor domain wall lattice QCD with large physical volumes and nearly-physical\npion masses at two lattice spacings. We perform a short, O(3)%, extrapolation\nin pion mass to the physical values by combining our new data in a simultaneous\nchiral/continuum `global fit' with a number of other ensembles with heavier\npion masses. We use the physical values of $m_\\pi$, $m_K$ and $m_\\Omega$ to\ndetermine the two quark masses and the scale - all other quantities are outputs\nfrom our simulations. We obtain results with sub-percent statistical errors and\nnegligible chiral and finite-volume systematics for these light hadronic\nquantities, including: $f_\\pi$ = 130.2(9) MeV; $f_K$ = 155.5(8) MeV; the\naverage up/down quark mass and strange quark mass in the $\\bar {\\rm MS}$ scheme\nat 3 GeV, 2.997(49) and 81.64(1.17) MeV respectively; and the neutral kaon\nmixing parameter, $B_K$, in the RGI scheme, 0.750(15) and the $\\bar{\\rm MS}$\nscheme at 3 GeV, 0.530(11).",
        "positive": "Investigation of $B\\bar B$ four-quark systems using lattice QCD: We investigate $B \\bar B$ systems by computing potentials of two static\nquarks in the presence of two quarks of finite mass using lattice QCD. By\nsolving the Schr\\\"odinger equation we check whether these potentials are\nsufficiently attractive to host bound states. Particular focus is put on the\nexperimentally most promising bottomonium-like tetraquark candidate $Z_b^\\pm$\nwith quantum numbers $I(J^P)=1(1^+)$."
    },
    {
        "anchor": "Transport Properties of the Quark-Gluon Plasma -- A Lattice QCD\n  Perspective: Transport properties of a thermal medium determine how its conserved charge\ndensities (for instance the electric charge, energy or momentum) evolve as a\nfunction of time and eventually relax back to their equilibrium values. Here\nthe transport properties of the quark-gluon plasma are reviewed from a\ntheoretical perspective. The latter play a key role in the description of\nheavy-ion collisions, and are an important ingredient in constraining particle\nproduction processes in the early universe. We place particular emphasis on\nlattice QCD calculations of conserved current correlators. These Euclidean\ncorrelators are related by an integral transform to spectral functions, whose\nsmall-frequency form determines the transport properties via Kubo formulae. The\nuniversal hydrodynamic predictions for the small-frequency pole structure of\nspectral functions are summarized. The viability of a quasiparticle description\nimplies the presence of additional characteristic features in the spectral\nfunctions. These features are in stark contrast with the functional form that\nis found in strongly coupled plasmas via the gauge/gravity duality. A central\ngoal is therefore to determine which of these dynamical regimes the quark-gluon\nplasma is qualitatively closer to as a function of temperature. We review the\nanalysis of lattice correlators in relation to transport properties, and\ntentatively estimate what computational effort is required to make decisive\nprogress in this field.",
        "positive": "Finite-volume effects in the evaluation of the K_L - K_S mass difference: The RBC and UKQCD collaborations have recently proposed a procedure for\ncomputing the K_L-K_S mass difference. A necessary ingredient of this procedure\nis the calculation of the (non-exponential) finite-volume corrections relating\nthe results obtained on a finite lattice to the physical values. This requires\na significant extension of the techniques which were used to obtain the\nLellouch-Luscher factor, which contains the finite-volume corrections in the\nevaluation of non-leptonic kaon decay amplitudes. We review the status of our\nstudy of this issue and, although a complete proof is still being developed,\nsuggest the form of these corrections for general volumes and a strategy for\ntaking the infinite-volume limit. The general result reduces to the known\ncorrections in the special case when the volume is tuned so that there is a\ntwo-pion state degenerate with the kaon."
    },
    {
        "anchor": "Strongly coupled gauge theories: What can lattice calculations teach us?: The dynamical origin of electroweak symmetry breaking is an open question\nwith many possible theoretical explanations. Strongly coupled systems\npredicting the Higgs boson as a bound state of a new gauge-fermion interaction\nform one class of candidate models. Due to increased statistics, LHC run II\nwill further constrain the phenomenologically viable models in the near future.\nIn the meanwhile it is important to understand the general properties and\nspecific features of the different competing models.\n  In this work we discuss many-flavor gauge-fermion systems that contain both\nmassless (light) and massive fermions. The former provide Goldstone bosons and\ntrigger electroweak symmetry breaking, while the latter indirectly influence\nthe infrared dynamics. Numerical results reveal that such systems can exhibit a\nlight $0^{++}$ isosinglet scalar, well separated from the rest of the spectrum.\nFurther, when we set the scale via the $vev$ of electroweak symmetry breaking,\nwe predict a 2 TeV vector resonance which could be a generic feature of SU(3)\ngauge theories.",
        "positive": "Flux tubes and topological charges in finite-temperature lattice QCD: Topological properties of the vacuum were investigated in finite-temperature\nlattice QCD without and with dynamical quarks using a local operator of\ntopological charge density and a variant of cooling. Below the deconfinement\ntemperature evidence for flux tube formation was observed in the distribution\nof topological charge density around a static $Q\\bar Q$ pair. With dynamical\nquarks, the flux tube breaks when the distance between the static quark and\nantiquark increases."
    },
    {
        "anchor": "Constrained Hybrid Monte Carlo algorithms for gauge-Higgs models: We develop Hybrid Monte Carlo (HMC) algorithms for constrained Hamiltonian\nsystems of gauge- Higgs models and introduce a new observable for the\nconstraint effective Higgs potential. We use an extension of the so-called\nRattle algorithm to general Hamiltonians for constrained systems, which we\nadapt to the 4D Abelian-Higgs model and the 5D SU(2) gauge theory on the torus\nand on the orbifold. The derivative of the potential is measured via the\nexpectation value of the Lagrange multiplier for the constraint condition and\nallows a much more precise determination of the effective potential than\nconventional histogram methods. With the new method, we can access the\npotential over the full domain of the Higgs variable, while the histogram\nmethod is restricted to a short region around the expectation value of the\nHiggs field in unconstrained simulations, and the statistical precision does\nnot deteriorate when the volume is increased. We further verify our results by\ncomparing to the one-loop Higgs potential of the 4D Abelian-Higgs model in\nunitary gauge and find good agreement. To our knowledge, this is the first time\nthis problem has been addressed for theories with gauge fields. The algorithm\ncan also be used in four dimensions to study finite temperature and density\ntransitions via effective Polyakov loop actions.",
        "positive": "Current progress on the semileptonic form factors for $\\bar{B} \\to\n  D^{\\ast} \\ell \\bar\u03bd$ decay using the Oktay-Kronfeld action: We present recent progress in calculating the semileptonic form factors\n$h_{A_1}(w)$ for the $\\bar{B} \\to D^{\\ast} \\ell \\bar{\\nu}$ decays. We use the\nOktay-Kronfeld (OK) action for the charm and bottom valence quarks and the HISQ\naction for light quarks. We adopt the Newton method combined with the scanning\nmethod to find a good initial guess for the $\\chi^2$ minimizer in the fitting\nof the 2pt correlation functions. The main advantage is that the Newton method\nlets us to consume all the time slices allowed by the physical positivity. We\nreport the first, reliable, but preliminary results for $h_{A_1}(w)/\\rho_{A_1}$\nat zero recoil ($w=1$). Here we use a MILC HISQ ensemble ($a = 0.12$ fm,\n$M_{\\pi}$ = 220 MeV, and $N_f = 2 + 1 + 1$ flavors)."
    },
    {
        "anchor": "Partially quenched chiral perturbation theory for N=1 supersymmetric\n  Yang-Mills theory: Adding a gluino mass term to N=1 supersymmetric Yang-Mills theory breaks\nsupersymmetry softly. In order to approach the supersymmetric continuum limit\nin numerical simulations with the Wilson action, the bare gluino mass has to be\ntuned to the limit of vanishing renormalised gluino mass. This can be done\nefficiently by means of the mass of the adjoint pion, which is, however, an\nunphysical particle. We discuss how the adjoint pion can be defined in the\nframework of partially quenched chiral perturbation theory. A relation between\nits mass and the mass of the gluino, analogous to the Gell-Mann-Oakes-Renner\nrelation of QCD, can be derived.",
        "positive": "Improved local truncation schemes for the higher-order tensor\n  renormalization group method: The higher-order tensor renormalization group is a tensor-network method\nproviding estimates for the partition function and thermodynamical observables\nof classical and quantum systems in thermal equilibrium. At every step of the\niterative blocking procedure, the coarse-grid tensor is truncated to keep the\ntensor dimension under control. For a consistent tensor blocking procedure, it\nis crucial that the forward and backward tensor modes are projected on the same\nlower dimensional subspaces. In this paper we present two methods, the SuperQ\nand the iterative SuperQ method, to construct tensor truncations that reduce or\neven minimize the local approximation errors, while satisfying this constraint."
    },
    {
        "anchor": "Overlap Valence Quarks on a Twisted Mass Sea: We present the results of an investigation of a mixed action approach of\noverlap valence and maximally twisted mass sea quarks. Employing a particular\nmatching condition on the pion mass, we analyze the continuum limit scaling of\nthe pion decay constant and the role of chiral zero modes of the overlap\noperator in this process. We employ gauge field configurations generated by the\nEuropean Twisted Mass Collaboration with linear lattice size $L$ ranging from\n1.3 to 1.9 fm. The continuum limit is taken at a fixed value of $L=1.3$ fm,\nemploying three values of the lattice spacing and two values of the pion mass\nconstructed from sea quarks only.",
        "positive": "SU(2) Lattice Gluon Propagator and Potential Models: We study the bottomonium spectrum using a potential model. Our potential\nincorporates lattice results for the gluon propagator, obtained from\nsimulations of pure SU(2) gauge theory in Landau gauge. The mass of the bottom\nquark is left as a free parameter. The resulting spectrum is compared to the\ncase of the Coulomb plus Linear (or Cornell) Potential."
    },
    {
        "anchor": "Comment on A. Patrascioiu and E. Seiler's paper ``Nonuniformity of the\n  $1/N$ Expansion for Two-Dimensional $O(N)$ Models'': We remind that the non-uniformity in the temperature of the $1/N$ expansion\nfor dimensionful quantities pointed out in Patrascioiu and Seiler's paper is\nnot only compatible with but is predicted by asymptotic freedom, and it is\npresent in the continuum as well as on the lattice. The convergence of the\n$1/N$ expansion for adimensional quantities is perfectly uniform.",
        "positive": "Stabilising complex Langevin simulations: We present updated results of dynamic stabilisation (DS) applied to complex\nLangevin simulations of QCD in the heavy-dense limit and with staggered quarks.\nWe show that DS is able to keep the unitarity norm sufficiently small, which\nleads to excellent agreements with Monte-Carlo simulations, when the latter is\napplicable."
    },
    {
        "anchor": "Monte Carlo simulations of the randomly forced Burgers equation: The behaviour of the one--dimensional random--forced Burgers equation is\ninvestigated in the path integral formalism, using a discrete space--time\nlattice. We show that by means of Monte Carlo methods one may evaluate\nobservables, such as structure functions, as ensemble averages over different\nfield realizations. The regularization of shock solutions to the\nzero--viscosity limit (Hopf-eq.) eventually leads to constraints on lattice\nparameters, required for the stability of the simulations. Insight into the\nformation of localized structures (shocks) and their dynamics is obtained.",
        "positive": "Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte\n  Carlo (RHMC) Algorithm: Improved staggered fermion formulations are a popular choice for lattice QCD\ncalculations. Historically, the algorithm used for such calculations has been\nthe inexact R algorithm, which has systematic errors that only vanish as the\nsquare of the integration step-size. We describe how the exact Rational Hybrid\nMonte Carlo (RHMC) algorithm may be used in this context, and show that for\nparameters corresponding to current state-of-the-art computations it leads to a\nfactor of approximately seven decrease in cost as well as having no step-size\nerrors."
    },
    {
        "anchor": "A Real-Space Renormalization Group for Random Surfaces: We propose a new real-space renormalization group transformation for\ndynamical triangulations. It is shown to preserve geometrical exponents such as\nthe string susceptibility and Hausdorff dimension. We furthermore show evidence\nfor a fixed point structure both in pure gravity and gravity coupled to a\ncritical Ising system. In the latter case we are able to extract estimates for\nthe gravitationally dressed exponents which agree to within 2-3% of the KPZ\nformula.",
        "positive": "Dynamical role of Polyakov loops in the QCD thermodynamics: Polyakov loops $L_a(T), a=3,8,...$ are shown to give the most important\nnonperturbative contribution to the thermodynamic potentials. Derived from the\ngluonic field correlators they enter as factors into free energy. It is shown\nin the $SU(3)$ case that $L_a (T)$ define to a large extent the behavior of the\nfree energy and the trace anomaly $I(T)$, most sensitive to nonperturbative\neffects."
    },
    {
        "anchor": "Pion quasi parton distribution function on a fine lattice: We present a calculation of the bare quasi-PDF (qPDF) of the pion. We perform\nthese calculations using the HotQCD HISQ gauge ensemble for our sea quarks\nalong with a Wilson-Clover valence quark action. Our lattice size is\n$48^3\\times64$, our lattice spacing is set at a = 0.06 fm, and our pion mass is\ntuned to 300 MeV.\n  Utilizing momentum smearing techniques, we compute the bare qPDF boosted up\nto momentum 1.72 GeV. In addition we explore excited state contamination of the\nthree-point correlator.",
        "positive": "Two-dimensional phase structure of SU(2) gauge-Higgs model: We study the phase structure of SU(2) gauge-Higgs model in two dimensions\nusing lattice simulations. We show the result for the plaquette expectation\nvalue, static potential, and W propagator. Our results suggest that a\nconfinement-like region and a Higgs-like region appear even in two dimensions.\nThe behavior of the plaquette expectation value is consistent with a smooth\ncross-over in accordance with the Fradkin-Shenker-Osterwalder-Seiler theorem.\nIn the confinement-like region, the static potential seems to rise linearly\nwith string breaking at large distances, while in the Higgs-like region there\nseems to be a massive behavior which means that the BEH mechanism occurs. The\ncorrelation length obtained from the W propagator has a finite maximum between\nthese phases, which supports no second-order phase transition. Based on these\nresults, we suggest that there is no phase transition in two dimensions."
    },
    {
        "anchor": "Nucleon Magnetic Moments, their Quark Mass Dependence and Lattice QCD\n  Extrapolations: We calculate the quark mass dependence of both isovector and isoscalar\nanomalous magnetic moments of the nucleon in a chiral effective field theory\nwith explicit pion, nucleon and Delta(1232) degrees of freedom to\nleading-one-loop order. In the isovector sector we fit 3 unknown couplings of\nthe effective Lagrangian to available lattice data and obtain a surprisingly\nwell-behaved extrapolation function connecting the chiral limit, experimental\ndata and the lattice simulations. We also discuss the polynomial quark mass\ndependence in the isoscalar sector and finally compare with the Pade formula of\nthe Adelaide group.",
        "positive": "Localization of overlap modes and topological charge, vortices and\n  monopoles in SU(3) LGT: We present selected recent results of the QCDSF collaboration on the\nlocalization and dimensionality of low overlap eigenmodes and of the\ntopological density in the quenched SU(3) vacuum. We discuss the correlations\nbetween the topological structure revealed by overlap fermions without\nfiltering and the confining monopole and P-vortex structure obtained in the\nIndirect Maximal Center Gauge."
    },
    {
        "anchor": "Decay constant of $B_s$ and $B^*_s$ mesons from ${\\rm N_f}=2$ lattice\n  QCD}: We report on a two-flavor lattice QCD estimate of the $B_s$ and $B^*_s$\nleptonic decays parameterized by the decay constants $f_{B_s}$ and $f_{B^*_s}$.\nIn addition to their relevance for phenomenology, their extraction has allowed\nus to investigate whether the \"step scaling in mass\" strategy is suitable with\nWlilson-Clover fermions to smoothly extrapolate quantities of the heavy-strange\nsector up to the bottom scale. From the central value of $f_{D_s}$ quoted by\nFLAG at $N_f=2$ and our ratio $\\frac{f_{B_s}}{f_{D_s}}$, we obtain\n$f_{B_s}=215(10)(2)(^{+2}_{-5})$ MeV and\n$f_{B^*_s}/f_{B_s}=1.02(2)(^{+2}_{-0})$.",
        "positive": "Dual superconductivity and vacuum properties in Yang--Mills theories: We address, within the dual superconductivity model for color confinement,\nthe question whether the Yang-Mills vacuum behaves as a superconductor of type\nI or type II. In order to do that we compare, for the theory with gauge group\nSU(2), the determination of the field penetration depth $\\lambda$ with that of\nthe superconductor correlation length $\\xi$. The latter is obtained by\nmeasuring the temporal correlator of a disorder parameter developed by the Pisa\ngroup to detect dual superconductivity. The comparison places the vacuum close\nto the border between type I and type II and marginally on the type II side. We\nalso check our results against the study of directly measurable effects such as\nthe interaction between two parallel flux tubes, obtaining consistent\nindications for a weak repulsive behaviour. Future strategies to improve our\ninvestigation are discussed."
    },
    {
        "anchor": "Publicising Lattice Field Theory through Visualisation: The gluon field configurations that form the foundation of every lattice QCD\ncalculation contain a rich diversity of emergent nonperturbative structure.\nVisualisations of these phenomena not only serve to explain the concept of a\nnontrivial vacuum but also entertain a diverse audience from research funding\npanels to the next generation of science enthusiasts. In this brief review, a\ncollection of QCD-vacuum visualisations is presented including the structure of\nchromo-electromagnetic fields, centre-cluster evolution at finite temperature,\nthe structure of projected centre vortices, and novel correlations between the\nelectromagnetic fields of QED and the chromo-electromagnetic fields of QCD in\nQED+QCD dynamical-fermion simulations from the QCDSF collaboration.",
        "positive": "Infrared fixed point in the massless twelve-flavor SU(3) gauge-fermion\n  system: We present strong numerical evidence for the existence of an infrared fixed\npoint in the renormalization group flow of the SU(3) gauge-fermion system with\ntwelve massless fermions in the fundamental representation. Our numerical\nsimulations using nHYP-smeared staggered fermions with Pauli-Villars\nimprovement do not exhibit any first-order bulk phase transition in the\ninvestigated parameter region. We utilize an infinite volume renormalization\nscheme based on the gradient flow transformation to determine the\nrenormalization group $\\beta$ function. We identify an infrared fixed point at\n$g^2_{\\mathrm{GF}\\star}=6.60(62)$ in the GF scheme and calculate the leading\nirrelevant critical exponent $\\gamma_{g}^{\\star}=0.199(32)$. Our prediction for\n$\\gamma_{g}^{\\star}$ is consistent with available literature at the\n$1\\mbox{-}2\\sigma$ level."
    },
    {
        "anchor": "The chromomagnetic operator on the lattice: We present our study of the renormalization of the chromomagnetic\noperator,O(CM), which appears in the effective Hamiltonian describing Delta S =\n1 transitions in and beyond the Standard Model. We have computed,\nperturbatively to one-loop, the relevant Green's functions with two\n(quark-quark) and three (quark-quark-gluon) external fields, at nonzero quark\nmasses, using both the lattice and dimensional regularizations. The\nperturbative computation on the lattice is carried out using the maximally\ntwisted-mass action for the fermions, while for the gluons we employed the\nSymanzik improved gauge action for different sets of values of the Symanzik\ncoefficients. We have identified all the operators which can possibly mix with\nO(CM), including lower dimensional and non gauge invariant operators, and we\nhave calculated those elements of the mixing matrix which are relevant for the\nrenormalization of O(CM). We have also performed numerical lattice calculations\nto determine non-perturbatively the mixings of the chromomagnetic operator with\nlower dimensional operators, through proper renormalization conditions. For the\nfirst time the 1/a**2-divergent mixing of the chromomagnetic operator with the\nscalar density has been determined non-perturbatively with high precision.\nMoreover, the 1/a-divergent mixing with the pseudoscalar density, due to the\nbreaking of parity within the twisted-mass regularization of QCD, has been\ncalculated non-perturbatively and found to be smaller than its one-loop\nperturbative estimate. The QCD simulations have been carried out using the\ngauge configurations produced by the European Twisted Mass Collaboration with\nNf = 2 + 1 + 1 dynamical quarks, which include in the sea, besides two light\nmass degenerate quarks, also the strange and charm quarks with masses close to\ntheir physical values.",
        "positive": "Use of even Grassmann variables to construct effective actions for\n  mesons: A quadratic action in even Grassmann variables with the quantum numbers of\nthe pions has been studied. It includes the $\\sigma$-field in order to be\ninvariant under SU(2)_L times SU(2)_R transformations over the quarks. This\naction exhibits the Goldstone phenomenon reducing its symmetry to the O(3)\nisospin invariance. The model has been investigated in the\nStratonovitch-Hubbard representation, in which form it is reminiscent of the\nGell-Mann-Levy model. By the saddle point method a renormalizable expansion in\ninverse powers of the index of nilpotency of the mesonic fields (which is 24),\nis generated. The way it might be used in a new perturbative approach to QCD is\noutlined."
    },
    {
        "anchor": "Computing the static potential using non-string-like trial states: We present a method for computing the static quark-antiquark potential, which\nis not based on Wilson loops, but where the trial states are formed by\neigenvector components of the covariant lattice Laplace operator. We have\ntested this method in SU(2) Yang-Mills theory and have obtained results with\nstatistical errors of similar magnitude compared to a standard Wilson loop\ncomputation. The runtime of the method is, however, significantly smaller, when\ncomputing the static potential not only for on-axis, but also for many off-axis\nquark-antiquark separations, i.e. when a fine spatial resolution is required.",
        "positive": "The dual sector of the \u03c6^4 Theory in 4D: The one-component $\\lambda\\phi^4$ theory in four dimensions in the\nspontaneously broken symmetry phase has a non-trivial, non-perturbative sector\nwhich can be studied by means of a duality transformation of its Ising limit.\nDuality maps this theory to a model of interacting membranes. Physical states\ncorrespond to membrane excitations. The way this non-perturbative behaviour can\nbe reconciled with the triviality of the theory in its continuum limit is\ndiscussed."
    },
    {
        "anchor": "Different definitions of the chemical potential with identical partition\n  function in QCD on a lattice: It is shown that starting from one and the same transfer matrix formulation\nof QCD on a lattice, it is possible to obtain both the action of Hasenfratz and\nKarsch as well as an action where the chemical potential is not coupled to the\ntemporal links.",
        "positive": "Reweighting towards the chiral limit: We propose to perform fully dynamical simulations at small quark masses by\nreweighting in the quark mass. This approach avoids some of the technical\ndifficulties associated with direct simulations at very small quark masses. We\ncalculate the weight factors stochastically, using determinant breakup and low\nmode projection to reduce the statistical fluctuations. We find that the weight\nfactors fluctuate only moderately on nHYP smeared dynamical Wilson-clover\nensembles, and we could successfully reweight 16^4, (1.85fm)^4 volume\nconfigurations from m_q = 20MeV to m_q = 5MeV quark masses, reaching the\nepsilon-regime. We illustrate the strength of the method by calculating the low\nenergy constant F from the epsilon-regime pseudo-scalar correlator."
    },
    {
        "anchor": "Regularity Properties and Pathologies of Position-Space\n  Renormalization-Group Transformations: We reconsider the conceptual foundations of the renormalization-group (RG)\nformalism, and prove some rigorous theorems on the regularity properties and\npossible pathologies of the RG map. Regarding regularity, we show that the RG\nmap, defined on a suitable space of interactions (= formal Hamiltonians), is\nalways single-valued and Lipschitz continuous on its domain of definition. This\nrules out a recently proposed scenario for the RG description of first-order\nphase transitions. On the pathological side, we make rigorous some arguments of\nGriffiths, Pearce and Israel, and prove in several cases that the renormalized\nmeasure is not a Gibbs measure for any reasonable interaction. This means that\nthe RG map is ill-defined, and that the conventional RG description of\nfirst-order phase transitions is not universally valid. For decimation or\nKadanoff transformations applied to the Ising model in dimension $d \\ge 3$,\nthese pathologies occur in a full neighborhood $\\{ \\beta > \\beta_0 ,\\, |h| <\n\\epsilon(\\beta) \\}$ of the low-temperature part of the first-order\nphase-transition surface. For block-averaging transformations applied to the\nIsing model in dimension $d \\ge 2$, the pathologies occur at low temperatures\nfor arbitrary magnetic-field strength. Pathologies may also occur in the\ncritical region for Ising models in dimension $d \\ge 4$. We discuss in detail\nthe distinction between Gibbsian and non-Gibbsian measures, and give a rather\ncomplete catalogue of the known examples. Finally, we discuss the heuristic and\nnumerical evidence on RG pathologies in the light of our rigorous theorems.",
        "positive": "Colour Fields of the Static Pentaquark System Computed in SU(3) Lattice\n  QCD: We compute the colour fields of SU(3) lattice QCD created by static\npentaquark systems, in a $24^3\\times 48$ lattice at $\\beta=6.2$ corresponding\nto a lattice spacing $a=0.07261(85)$ fm. We find that the pentaquark colour\nfields are well described by a multi-Y-type shaped flux tube. The flux tube\njunction points are compatible with Fermat-Steiner points minimizing the total\nflux tube length. We also compare the pentaquark flux tube profile with\ndiquark-diantiquark central flux tube profile in the tetraquark and the\nquark-antiquark fundamental flux tube profile in the meson, and they match,\nthus showing that the pentaquark flux tubes are composed of fundamental flux\ntubes."
    },
    {
        "anchor": "Charmonium near the deconfining transition on the lattice: We study the charmonium properties at finite temperature using quenched\nlattice QCD simulations. Although a simple potential model analysis indicates\nno bound state at $T>1.05T_c$, our analyses of the spatial correlation between\nquark and anti-quark and the spectral function indicate that a bound-state-like\nstructure may survive even above $T_c$.",
        "positive": "Phase diagram at finite temperature and quark density in the strong\n  coupling region of lattice QCD for color SU(3): We study the phase diagram of quark matter at finite temperature (T) and\nchemical potential (mu) in the strong coupling region of lattice QCD for color\nSU(3). Baryon has effects to extend the hadron phase to a larger mu direction\nrelative to Tc at low temperatures in the strong coupling limit. With the 1/g^2\ncorrections, Tc is found to decrease rapidly as g decreases, and the shape of\nthe phase diagram becomes closer to that expected in the real world."
    },
    {
        "anchor": "N=1 super Yang-Mills on the lattice: We present results from a numerical study of N=1 supersymmetric Yang-Mills\ntheory using domain wall fermions. A set of dynamical simulations were\nperformed for the gauge group SU(2) using the Wilson gauge action on 8^3x8 and\n16^3x32 lattices. We considered a range of gluino masses (i.e., fifth dimension\nextents L_s=16-28 and input gluino mass values m_f=0.01-0.04) in order to\nperform chiral limit extrapolations of physical quantities. In these\nproceedings, we summarize our findings from a study of the Dirac spectrum and\npresent new results for the topological charge on beta=2.3, 2.353 and 2.4\nensembles.",
        "positive": "$B \\to \u03c0\\ell\u03bd$ form factors and $|V_{ub}|$ with M\u00f6bius domain wall\n  fermions: We report on a calculation of form factors for the semileptonic decay of $B$\nmeson to pion on $2+1$-flavour lattices with lattice spacings from 0.080 fm\ndown to 0.044 fm. Using the M\\\"obius domain wall fermion action for both sea\nand valence quarks, we simulate pions with masses down to 225 MeV. By utilizing\na range of heavy quark masses up to 2.44 times the mass of the charm quark we\nextrapolate to the physical $b$ quark mass. We discuss the dependence of the\nform factors on the pion mass, heavy quark mass, lattice spacing and the\nmomentum-transfer. We extract the CKM matrix element $|V_{ub}|$ through a\nsimultaneous fit with the $B \\to \\pi\\ell\\nu$ differential branching fractions\nprovided by the Belle and BaBar collaborations after a chiral-continuum and\nphysical $b$ quark extrapolations of our lattice data."
    },
    {
        "anchor": "A framework for the calculation of the $\u0394N\u03b3^*$ transition\n  form factors on the lattice: Using the non-relativistic effective field theory framework in a finite\nvolume, we discuss the extraction of the $\\Delta N\\gamma^*$ transition form\nfactors from lattice data. A counterpart of the L\\\"uscher approach for the\nmatrix elements of unstable states is formulated. In particular, we thoroughly\ndiscuss various kinematic settings, which are used in the calculation of the\nabove matrix element on the lattice. The emerging L\\\"uscher-Lellouch factor and\nthe analytic continuation of the matrix elements into the complex plane are\nalso considered in detail. A full group-theoretical analysis of the problem is\nmade, including the partial-wave mixing and projecting out the invariant form\nfactors from data.",
        "positive": "Chiral Ward identities for Dirac eigenmodes with staggered fermions: We study chiral properties of eigenvalue spectrum for staggered quarks. We\npresent a new method to identify would-be zero modes and nonzero modes using\ntheir symmetry and chiral properties. Here, we review the traditional method\nwith HYP improved staggered quarks, and extend it to a completely new method\nwhich uses the chiral Ward identities and leakage patterns to achieve the goal."
    },
    {
        "anchor": "QCD with Flavored Minimally Doubled Fermions: I discuss minimally doubled fermions fermions as an ultra-local formulation\non the lattice for sea quarks that realize a non-singlet chiral symmetry. I\nintroduce a non-singlet mass term for Karsten-Wilczek fermions and identify the\nappropriate representation of the SU(2) flavor group at finite lattice spacing.\nI present an algebraic proof that the symmetry of the quark determinant under\ncharge conjugation and reflections of the Euclidean axes is preserved for\nKarsten-Wilczek fermions as sea quarks. Finally, I discuss how the flavor\ncomponents in meson correlation functions with Karsten-Wilczek fermions emerge\nnaturally and I show how taste-breaking can be avoided without fine tuning.",
        "positive": "Dirac Spectra of 2-dimensional QCD-like theories: We analyze Dirac spectra of two-dimensional QCD like theories both in the\ncontinuum and on the lattice and classify them according to random matrix\ntheories sharing the same global symmetries. The classification is different\nfrom QCD in four dimensions because the anti-unitary symmetries do not commute\nwith $\\gamma_5$. Therefore in a chiral basis, the number of degrees of freedom\nper matrix element are not given by the Dyson index. Our predictions are\nconfirmed by Dirac spectra from quenched lattice simulations for QCD with two\nor three colors with quarks in the fundamental representation as well as in the\nadjoint representation. The universality class of the spectra depends on the\nparity of the number of lattice points in each direction. Our results show an\nagreement with random matrix theory that is qualitatively similar to the\nagreement found for QCD in four dimensions. We discuss the implications for the\nMermin-Wagner-Coleman theorem and put our results in the context of\ntwo-dimensional disordered systems."
    },
    {
        "anchor": "The Analysis of Space-Time Structure in QCD Vacuum I: Localization vs\n  Global Behavior in Local Observables and Dirac Eigenmodes: The structure of QCD vacuum can be studied from first principles using\nlattice-regularized theory. This line of research entered a qualitatively new\nphase recently, wherein the space-time structure (at least for some quantities)\ncan be directly observed in configurations dominating the QCD path integral,\ni.e. without any subjective processing of typical configurations. This approach\nto QCD vacuum structure does not rely on any proposed picture of QCD vacuum but\nrather attempts to characterize this structure in a model-independent manner,\nso that a coherent physical picture of the vacuum can emerge when such unbiased\nnumerical information accumulates to a sufficient degree. An important part of\nthis program is to develop a set of suitable quantitative characteristics\ndescribing the space-time structure in a meaningful and physically relevant\nmanner. One of the basic pertinent issues here is whether QCD vacuum dynamics\ncan be understood in terms of localized vacuum objects, or whether such objects\nbehave as inherently global entities. The first direct studies of vacuum\nstructure strongly support the latter. In this paper, we develop a formal\nframework which allows to answer this question in a quantitative manner. We\ndiscuss in detail how to apply this approach to Dirac eigenmodes and to basic\nscalar and pseudoscalar composites of gauge fields (action density and\ntopological charge density). The approach is illustrated numerically on overlap\nDirac zeromodes and near-zeromodes. This illustrative data provides direct\nquantitative evidence supporting our earlier arguments for the global nature of\nQCD Dirac eigenmodes.",
        "positive": "Light-quark contributions to the magnetic form factor of the\n  Lambda(1405): In a recent study of the Lambda(1405), the suppression of the strange-quark\ncontribution to the magnetic form factor was interpreted as the discovery of a\ndominant antikaon-nucleon composition for this low-lying state. We confirm this\nresult by calculating the light u- and d-quark contributions to the\nLambda(1405) magnetic form factor in lattice QCD in order to determine the\nextent to which their contributions support this exotic molecular description.\nDrawing on the recent graded-symmetry approach for the flavor-singlet\ncomponents of the Lambda(1405), the separation of connected and disconnected\ncontributions is performed in both the flavor-octet and singlet\nrepresentations. The relationship between light-quark contributions to the\nLambda(1405) magnetic form factor and the connected contributions of the\nnucleon magnetic form factors is established and compared with lattice\ncalculations of the same quantities, confirming the KN molecular structure of\nthe Lambda(1405) in lattice QCD."
    },
    {
        "anchor": "Stout-smearing, gradient flow and $c_{\\text{SW}}$ at one loop order: The one-loop determination of the coefficient $c_\\text{SW}$ of the Wilson\nquark action has been useful to push the leading cut-off effects for on-shell\nquantities to $\\mathcal{O}(\\alpha^2 a)$ and, in conjunction with\nnon-perturbative determinations of $c_\\text{SW}$, to $\\mathcal{O}(a^2)$, as\nlong as no link-smearing is employed. These days it is common practice to\ninclude some overall link-smearing into the definition of the fermion action.\nUnfortunately, in this situation only the tree-level value\n$c_\\text{SW}^{(0)}=1$ is known, and cut-off effects start at\n$\\mathcal{O}(\\alpha a)$. We present some general techniques for calculating one\nloop quantities in lattice perturbation theory which continue to be useful for\nsmeared-link fermion actions. Specifically, we discuss the application to the\n1-loop improvement coefficient $c_\\text{SW}^{(1)}$ for overall stout-smeared\nWilson fermions.",
        "positive": "An additional symmetry in the Weinberg - Salam model: An additional $Z_6$ symmetry hidden in the fermion and Higgs sectors of the\nStandard Model has been found recently. It has a singular nature and is\nconnected to the centers of the SU(3) and SU(2) subgroups of the gauge group. A\nlattice regularization of the Standard Model was constructed that possesses\nthis symmetry. In this paper we report our results on the numerical simulation\nof its Electroweak sector."
    },
    {
        "anchor": "Pion masses in 2-flavor QCD with $\u03b7$ condensation: We investigate some aspects of 2-flavor QCD with $m_u\\not= m_d$ at\nlow-energy, using the leading order chiral perturbation theory including\nanomaly effects. While nothing special happens at $m_u=0$ for the fixed\n$m_d\\not=0$, the neutral pion mass becomes zero at two critical values of\n$m_u$, between which the neutral pion field condenses, leading to a\nspontaneously CP broken phase, the so-called Dashen phase. We also show that\nthe \"topological susceptibility\" in the ChPT diverges at these two critical\npoints. We briefly discuss a possibility that $m_u=0$ can be defined by the\nvanishing the \"topological susceptibility. We finally analyze the case of\n$m_u=m_d=m$ with $\\theta=\\pi$, which is equivalent to $m_u= - m_d=-m$ with\n$\\theta = 0$ by the chiral rotation. In this case, the $\\eta$ condensation\noccurs at small $m$, violating the CP symmetry spontaneously. Deep in the\n$\\eta$ condensation phase, three pions become Nambu-Goldstone bosons, but they\nshow unorthodox behavior at small $m$ that $m_\\pi^2 = O(m^2)$, which, however,\nis shown to be consistent with the chiral Ward-Takahashi identities.",
        "positive": "Maximal variance reduction for stochastic propagators with applications\n  to the static quark spectrum: We study a new method -- maximal variance reduction -- for reducing the\nvariance of stochastic estimators for quark propagators. We find that while\nthis method is comparable to usual iterative inversion for light-light mesons,\na considerable improvement is achieved for systems containing at least one\ninfinitely heavy quark. Such systems are needed for heavy quark effective\ntheory. As an illustration of the effectiveness of the method we present\nresults for the masses of the ground state and excited states of $\\bar{Q}q$\nmesons and $\\bar{Q}qq$ baryons. We compare these results with the experimental\nspectra involving $b$ quarks."
    },
    {
        "anchor": "Electromagnetic Corrections in Staggered Chiral Perturbation Theory: To reduce errors in light-quark mass determinations, it is now necessary to\nconsider electromagnetic contributions to light-meson masses. Calculations\nusing staggered quarks and quenched photons are currently underway.\nSuitably-extended chiral perturbation theory is necessary to extrapolate the\nlattice data to the physical limit. Here we give (preliminary) results for\nlight-meson masses using staggered chiral perturbation theory including\nelectromagnetism, and discuss the extent to which quenched-photon simulations\ncan improve quark-mass calculations.",
        "positive": "Short-flow-time expansion of quark bilinears through\n  next-to-next-to-leading order QCD: The gradient-flow formalism proves to be a useful tool in lattice\ncalculations of quantum chromodynamics. For example, it can be used as a scheme\nto renormalize composite operators by inverting the short-flow-time expansion\nof the corresponding flowed operators. In this paper, we consider the\nshort-flow-time expansion of five quark bilinear operators, the scalar,\npseudoscalar, vector, axialvector, and tensor currents, and compute the\nmatching coefficients through next-to-next-to-leading order QCD. Among other\napplications, our results constitute one ingredient for calculating bag\nparameters of mesons within the gradient-flow formalism on the lattice."
    },
    {
        "anchor": "Direct access to hadronic decay parameters with twisted boundary\n  conditions: Our exploratory study looks for direct access to the resonant hadronic\ntransition amplitude without resorting to the L\\\"uscher formalism. We study the\ndecay $\\Psi(3770)\\to\\bar{D}D$ by applying partially twisted boundary conditions\nto the quenched charm quark, circumventing possible problems with final state\ninteractions. If successful, we could compute the dependence of the transition\namplitude on the charm-quark mass and test the predictions made by\nphenomenological quark-pair-creation models. Finally, we study if and to what\nextent an extraction of the excited state $\\Psi(3770)$ is necessary for this\nanalysis.",
        "positive": "Pion screening mass at finite chemical potential: We present a method to compute the responses of meson screening masses to the\nchemical potential by Taylor expanding the correlator using lattice QCD\nsimulation. We start by comparing the free theory lattice results with the\nanalytical expression. Then, using symmetry arguments, we obtain an expression\nfor the correlator in a series of the chemical potential at finite temperature.\nUsing this, we obtain the lowest order correction to the screening mass at a\nfinite chemical potential for temperatures around 2.5 GeV. Our lattice analysis\nis limited to isoscalar chemical potential for the pseudoscalar channel. The\ncalculations were performed using (2+1)-flavors of the Highly Improved\nStaggered Quark (HISQ/tree) action, with the ratio of the strange quark mass to\nthe light quark mass $m_s/m_\\ell=20$ corresponding to pion masses of 160 MeV."
    },
    {
        "anchor": "Eigenvalues and Eigenvectors of the Staggered Dirac Operator at Finite\n  Temperature: We examine the eigenvalues and eigenvectors of the staggered Dirac operator\non thermal ensembles created in QCD with two flavours of staggered quarks. We\nsee that across the phase transition a gap opens in the spectrum. For finite\nvolume lattices in the low-temperature phase the eigenvectors are extended, but\ngeneric field configurations in the high temperature phase give rise to\nlocalized eigenstates. We examine measures of the stability of such\nlocalization and find that at finite volumes localization occurs through Mott's\nmechanism of the formation of mobility edges. However, the band gap between the\nlocalized and extended states seem to scale to zero in the limit of large\nvolume.",
        "positive": "Bulk-preventing actions for SU(N) gauge theories: We introduce a one-parameter family of SU(N) gauge actions which, when used\nin combination with an HMC update algorithm, prevent the gauge system from\nentering an artificial bulk-\"phase\". We briefly discuss the mechanism behind\nthe bulk-prevention and present test results for different SU(N) gauge groups."
    },
    {
        "anchor": "Electromagnetic Form Factors of Nucleon Excitations in Lattice QCD: Variational analysis techniques in lattice QCD are powerful tools that give\naccess to the full spectrum of QCD. At zero momentum, these techniques are well\nestablished and can cleanly isolate energy eigenstates of either positive or\nnegative parity. In order to compute the form factors of a single energy\neigenstate, we must perform a variational analysis at non-zero momentum. When\nwe do this with baryons, we run into issues with parity mixing in the Dirac\nspinors, as boosted baryons are not eigenstates of parity. Due to this parity\nmixing, care must be taken to ensure that the projected correlation functions\nprovided by the variational analysis correspond to the same states at zero\nmomentum. This can be achieved through the parity-expanded variational analysis\n(PEVA) technique, a novel method developed at the University of Adelaide for\nensuring the successful and consistent isolation of boosted baryons. Utilising\nthis technique, we are able to compute the form factors of baryon excitations\nwithout contamination from other states. We present world-first calculations of\nexcited state nucleon form factors using this new technique.",
        "positive": "Progress in the determination of Mellin moments of the pion LCDA using\n  the HOPE method: The pion light-cone distribution amplitude (LCDA) is a central\nnon-perturbative object of interest for the calculation of high-energy\nexclusive processes in quantum chromodynamics. In this article, we discuss the\ncalculation of the second and fourth Mellin moment of the pion LCDA using a\nheavy-quark operator product expansion. The resulting value for the second\nMellin moment is $ \\langle{ \\xi^2 }\\rangle(\\mu = 2~\\text{GeV})= 0.210 \\pm\n0.013\\text{ (stat.)} \\pm 0.034\\text{ (sys.)}$. This result is compatible with\nthose from previous determinations of this quantity."
    },
    {
        "anchor": "Tensor renormalization group study of two-dimensional U(1) lattice gauge\n  theory with a $\u03b8$ term: We make an analysis of the two-dimensional U(1) lattice gauge theory with a\n$\\theta$ term by using the tensor renormalization group. Our numerical result\nfor the free energy shows good consistency with the exact one at finite\ncoupling constant. The topological charge density generates a finite gap at\n$\\theta=\\pi$ toward the thermodynamic limit. In addition finite size scaling\nanalysis of the topological susceptibility up to $V=L\\times L=1024\\times 1024$\nallows us to determine the phase transition at $\\theta=\\pi$ is the first order.",
        "positive": "Systematics analyses on nucleon isovector observables in 2+1-flavor\n  dynamical domain-wall lattice QCD near physical mass: Analyses on possible systematics in some isovector nucleon observables in the\nRBC+UKQCD 2+1-flavor dynamical domain-wall fermion (DWF) lattice-QCD are\npresented. The vector charge, axial charge, quark momentum and helicity\nfractions, and transversity are discussed using mainly the\nIwasaki\\(\\times\\)DSDR ensemble at pion mass of 170 MeV. No autocorrelation\nissue is observed in the vector charge and quark momentum and helicity\nfractions. Blocked Jack-knife analyses expose significant growth of estimated\nerror for the axial charge with increasing block sizes that are similar to or\nlarger than the known autocorrelation time of the gauge-field topological\ncharge. Similar growth is seen in the transversity. These two observables,\nhowever, do not seem correlated with the topological charge."
    },
    {
        "anchor": "Hadron Spectrum from Lattice QCD: A brief review is given of the lattice QCD calculation of the hadron\nspectrum. The status of current attempts toward inclusion of dynamical up, down\nand strange quarks is summarized focusing on our own work. Recent work on the\npossible existence of pentaquark states are assessed. We touch upon the PACS-CS\nProject for building our next machine for lattice QCD, and conclude with a\nnear-term physics and machine prospects.",
        "positive": "Complex Langevin dynamics at finite chemical potential: mean field\n  analysis in the relativistic Bose gas: Stochastic quantization can potentially be used to simulate theories with a\ncomplex action due to a nonzero chemical potential. We study complex Langevin\ndynamics in the relativistic Bose gas analytically, using a mean field\napproximation. We concentrate on the region with a Silver Blaze problem and\ndiscuss convergence, stability, fixed points, and the severeness of the sign\nproblem. The real distribution satisfying the extended Fokker-Planck equation\nis constructed and its nonlocal form is explained. Finally, we compare the mean\nfield results in finite volume with the numerical data presented in Ref. [1]."
    },
    {
        "anchor": "A linear sigma model for multiflavor gauge theories: We consider a linear sigma model describing $2N_f^2$ bosons ($\\sigma$, ${\\bf\na_0}$, $\\eta '$ and ${\\bf \\pi}$) as an approximate effective theory for a\n$SU(3)$ local gauge theory with $N_f$ Dirac fermions in the fundamental\nrepresentation. The model has a renormalizable $U(N_f)_L\\bigotimes U(N_f)_R$\ninvariant part, which has an approximate $O(2N_f^2)$ symmetry, and two\nadditional terms, one describing the effects of a $SU(N_f)_V$ invariant mass\nterm and the other the effects of the axial anomaly. We calculate the spectrum\nfor arbitrary $N_f$. Using preliminary and published lattice results from the\nLatKMI collaboration, we found combinations of the masses that vary slowly with\nthe explicit chiral symmetry breaking and $N_f$. This suggests that the anomaly\nterm plays a leading role in the mass spectrum and that simple formulas such as\n$M_\\sigma^2\\simeq (2/N_f-C_\\sigma)M_{\\eta '}^2$ should apply in the chiral\nlimit. Lattice measurements of $M_{\\eta '}^2$ and of approximate constants such\nas $C_\\sigma$ could help locating the boundary of the conformal window. We show\nthat our calculation can be adapted for arbitrary representations of the gauge\ngroup and in particular to the minimal model with two sextets, where similar\npatterns are likely to apply.",
        "positive": "Fixed twist dynamics of SO(3) gauge theory: We perform a throughout study of 3+1 dim. SO(3) LGT for any fixed-twist\nbackground. We concentrate in particular on the physically significant trivial\nand 1-twist sectors. Introducing a Z(2) monopole chemical potential the 1st\norder bulk transition is moved down in the strong coupling region and weakened\nto 2nd order in the 4-dim Ising model universality class. In this extended\nphase diagram we gain access to a confined phase in every fixed twist sector of\nthe theory. The Pisa disorder operator is employed together with the Polyakov\nloop to study the confinement-deconfinement transition in each sector. Due to\nthe specific properties of both operators, most results can be used to gain\ninsight in the ergodic theory, where all twist sectors should be summed upon.\nAn explicit mapping of each fixed twist theory to effective positive plaquette\nmodels with fixed twisted boundary conditions is applied to better establish\ntheir properties in the different phases."
    },
    {
        "anchor": "Embedded vortices and their interactions at electroweak crossover: We study properties of Z-vortices in the crossover region of the 3D SU(2)\nHiggs model. Correlators of the vortex currents with gauge field energy and\nHiggs field squared (\"quantum vortex profile\") reveal a structure that can be\ncompared with a classical vortex. We define a core size and a penetration depth\nfrom the vortex profile. Z-vortices are found to interact with each other\nanalogously to Abrikosov vortices in a type-I superconductor.",
        "positive": "Standard Model with the additional $Z_6$ symmetry on the lattice: An additional $Z_6$ symmetry hidden in the fermion and Higgs sectors of the\nStandard Model has been found recently\\cite{BVZ2003}. A lattice regularization\nof the Standard Model was constructed that possesses this symmetry. In\n\\cite{BVZ2004} we have reported our results on the numerical simulation of the\nElectroweak sector of the model. In this paper we report our results on the\nnumerical simulation of the full ($SU(3)\\otimes SU(2) \\otimes U(1)$) model. The\nphase diagram of the model has been investigated using static quark and lepton\npotentials. Various types of monopoles have been constructed. Their densities\nappear to be sensitive to the phase transition lines. Differences between the\nrealizations of the Standard Model which do or do not possess the mentioned\n$Z_6$ symmetry, are discussed."
    },
    {
        "anchor": "Lattice and Continuum Theories: We investigate path integral formalism for continuum theory. It is shown that\nthe path integral for the soft modes can be represented in the form of a\nlattice theory. Kinetic term of this lattice theory has a standard form and\npotential term has additional nonlocal terms which contributions should tend to\nzero in the limit of continuum theory. Contributions of these terms can be\nestimated. It is noted that this representation of path integral may be useful\nto improve lattice calculations taking into account hard modes contribution by\nstandard perturbative expansion. We discuss translation invariance of\ncorrelators and the possibility to construct a lattice theory which keeps\nrotary invariance also.",
        "positive": "Phase Structures of U(2) Gauge Theory with $\u03b8$-Term in 2 dimensions: U(2) lattice gauge theory with $\\theta$-term in 2 space-time dimensions is\ninvestigated. It has non-Abelian real action and Abelian( U(1) type) imaginary\naction. The imaginary action is defined as the standard $\\theta$-term. As the\neffect of renormalization group (RG) transformation, non-Abelian imaginary\naction is induced. After many steps of RG transformation, non-Abelian part will\ndie away. After several steps of RG transformations, renormalized action\napproaches so called heat kernel action. Phase transition is found at $\\theta\n=\\pi$ only."
    },
    {
        "anchor": "Generalized parton distributions of the proton from lattice QCD: Generalized parton distributions (GPDs) are among the most fundamental\nquantities for describing the internal structure of hadrons. In this work, we\npresent results on isovector GPDs of the proton obtained within lattice Quantum\nChromodynamics. We use the quasi-distribution formalism and perform the\ncalculations on an ensemble of $N_f = 2 + 1 + 1$ twisted mass fermions, with\npion mass $M_\\pi=260$~MeV and lattice spacing $a\\simeq 0.093$~fm. Results are\npresented for unpolarized, helicity, and transversity GPDs at zero and nonzero\nskewness with controlled statistical uncertainties. Comparisons with their\nforward limit show qualitative features anticipated from model calculations.",
        "positive": "Charmonium Spectrum from Quenched Anisotropic Lattice QCD: We present a detailed study of the charmonium spectrum using anisotropic\nlattice QCD. We first derive a tree-level improved clover quark action on the\nanisotropic lattice for arbitrary quark mass. The heavy quark mass dependences\nof the improvement coefficients, i.e. the ratio of the hopping parameters\n$\\zeta=K_t/K_s$ and the clover coefficients $c_{s,t}$, are examined at the tree\nlevel. We then compute the charmonium spectrum in the quenched approximation\nemploying $\\xi = a_s/a_t = 3$ anisotropic lattices. Simulations are made with\nthe standard anisotropic gauge action and the anisotropic clover quark action\nat four lattice spacings in the range $a_s$=0.07-0.2 fm. The clover\ncoefficients $c_{s,t}$ are estimated from tree-level tadpole improvement. On\nthe other hand, for the ratio of the hopping parameters $\\zeta$, we adopt both\nthe tree-level tadpole-improved value and a non-perturbative one. We calculate\nthe spectrum of S- and P-states and their excitations. The results largely\ndepend on the scale input even in the continuum limit, showing a quenching\neffect. When the lattice spacing is determined from the $1P-1S$ splitting, the\ndeviation from the experimental value is estimated to be $\\sim$30% for the\nS-state hyperfine splitting and $\\sim$20% for the P-state fine structure. Our\nresults are consistent with previous results at $\\xi = 2$ obtained by Chen when\nthe lattice spacing is determined from the Sommer scale $r_0$. We also address\nthe problem with the hyperfine splitting that different choices of the clover\ncoefficients lead to disagreeing results in the continuum limit."
    },
    {
        "anchor": "Getting even with CLE: In the landscape of approaches toward the simulation of Lattice Models with\ncomplex action the Complex Langevin (CL) appears as a straightforward method\nwith a simple, well defined setup. Its applicability, however, is controlled by\ncertain specific conditions which are not always satisfied. We here discuss the\nprocedures to meet these conditions and the estimation of systematic errors and\npresent some actual achievements.",
        "positive": "Hadron Spectrum with Wilson fermions: We present results of a high statistics study of the quenched spectrum using\nWilson fermions at $\\beta=6.0$ on $32^3 \\times 64$ lattices. We calculate the\nmasses of mesons and baryons composed of both degenerate and non-degenerate\nquarks. Using non-degenerate quark combinations allows us to study baryon mass\nsplittings in detail. We find significant deviations from the lowest order\nchiral expansion, deviations that are consistent with the expectations of\nquenched chiral perturbation theory. We find that there is a $\\sim 20%$\nsystematic error in the extracted value of $m_s$, depending on the meson mass\nratio used to set its value. Using the largest estimate of $m_s$ we find that\nthe extrapolated octet mass-splittings are in agreement with the experimental\nvalues, as is $M_\\Delta - M_N$, while the decuplet splittings are 30% smaller\nthan experiment. Combining our results with data from the GF11 collaboration we\nfind considerable ambiguity in the extrapolation to the continuum limit. Our\npreferred values are $M_N / M_\\rho = 1.38(7)$ and $M_\\Delta / M_\\rho =\n1.73(10)$, suggesting that the quenched approximation is good to only $\\sim\n10-15%$. We also analyze the $O(ma)$ discretization errors in heavy quark\nmasses."
    },
    {
        "anchor": "$|V_{us}|$ from $K_{\\ell 3}$ decay and four-flavor lattice QCD: Using HISQ $N_f=2+1+1$ MILC ensembles with five different values of the\nlattice spacing, including four ensembles with physical quark masses, we have\nperformed the most precise computation to date of the $K\\to\\pi\\ell\\nu$ vector\nform factor at zero momentum transfer,\n$f_+^{K^0\\pi^-}(0)=0.9696(15)_\\text{stat}(12)_\\text{syst}$. This is the first\ncalculation that includes the dominant finite-volume effects, as calculated in\nchiral perturbation theory at next-to-leading order. Our result for the form\nfactor provides a direct determination of the Cabibbo-Kobayashi-Maskawa matrix\nelement $|V_{us}|=0.22333(44)_{f_+(0)}(42)_\\text{exp}$, with a theory error\nthat is, for the first time, at the same level as the experimental error. The\nuncertainty of the semileptonic determination is now similar to that from\nleptonic decays and the ratio $f_{K^+}/f_{\\pi^+}$, which uses $|V_{ud}|$ as\ninput. Our value of $|V_{us}|$ is in tension at the 2--$2.6\\sigma$ level both\nwith the determinations from leptonic decays and with the unitarity of the CKM\nmatrix. In the test of CKM unitarity in the first row, the current limiting\nfactor is the error in $|V_{ud}|$, although a recent determination of the\nnucleus-independent radiative corrections to superallowed nuclear $\\beta$\ndecays could reduce the $|V_{ud}|^2$ uncertainty nearly to that of\n$|V_{us}|^2$. Alternative unitarity tests using only kaon decays, for which\nimprovements in the theory and experimental inputs are likely in the next few\nyears, reveal similar tensions. As part of our analysis, we calculated the\ncorrection to $f_+^{K\\pi}(0)$ due to nonequilibrated topological charge at\nleading order in chiral perturbation theory, for both the full-QCD and the\npartially-quenched cases. We also obtain the combination of low-energy\nconstants in the chiral effective Lagrangian\n$[C_{12}^r+C_{34}^r-(L_5^r)^2](M_\\rho)=(2.92\\pm0.31)\\cdot10^{-6}$.",
        "positive": "Unstable particles in finite volume: The broken phase of the $4$-d\n  $O(4)$ non-linear $\u03c3$-model: According to a proposal of L\\\"uscher it is possible to determine elastic\nscattering phases in infinite volume from the energy spectrum of two-particle\nstates in a periodic box.\n  We demonstrate the applicability of this method in the broken phase of the\n4-dimensional $O(4)$ non-linear $\\sigma$-model in a Monte-Carlo study on finite\nlattices.\n  This non-perturbative approach also permits the study of unstable particles,\nthe $\\sg$-particle in our case. We observe the $\\sg$-resonance and extract its\nmass and its width."
    },
    {
        "anchor": "Perfect Lattice Topology: The Quantum Rotor as a Test Case: Lattice actions and topological charges that are classically and quantum\nmechanically perfect (i.e. free of lattice artifacts) are constructed\nanalytically for the quantum rotor. It is demonstrated that the Manton action\nis classically perfect while the Villain action is quantum perfect. The\ngeometric construction for the topological charge is only perfect at the\nclassical level. The quantum perfect lattice topology associates a topological\ncharge distribution, not just a single charge, with each lattice field\nconfiguration. For the quantum rotor with the classically perfect action and\ntopological charge, the remaining cut-off effects are exponentially suppressed.",
        "positive": "B- and D-meson semileptonic decays with highly improved staggered quarks: We present results for $B_{(s)}$- and $D_{(s)}$-meson semileptonic decays\nfrom ongoing calculations by the Fermilab Lattice and MILC Collaborations. Our\ncalculation employs the highly improved staggered quark (HISQ) action for both\nsea and valence quarks and includes several ensembles with physical-mass up,\ndown, strange, and charm quarks and lattice spacings ranging from\n$a\\approx0.15$ fm down to 0.06 fm. At most lattice spacings, an ensemble with\nphysical-mass light quarks is included. The use of the highly improved action,\ncombined with the MILC Collaboration's gauge ensembles with lattice spacings\ndown to $a\\approx0.042$ fm, allows heavy valence quarks to be treated with the\nsame discretization as the light and strange quarks. This unified treatment of\nthe valence quarks allows (in some cases) for absolutely normalized currents,\nbypassing the need for perturbative matching, which has been a leading source\nof uncertainty in previous calculations of $B$-meson decay form factors by our\ncollaboration. All preliminary form-factor results are blinded."
    },
    {
        "anchor": "Level spacings for weakly asymmetric real random matrices and\n  application to two-color QCD with chemical potential: We consider antisymmetric perturbations of real symmetric matrices in the\ncontext of random matrix theory and two-color quantum chromodynamics. We\ninvestigate the level spacing distributions of eigenvalues that remain real or\nbecome complex conjugate pairs under the perturbation. We work out analytical\nsurmises from small matrices and show that they describe the level spacings of\nlarge random matrices. As expected from symmetry arguments, these level\nspacings also apply to the overlap Dirac operator for two-color QCD with\nchemical potential.",
        "positive": "Wilson flow and scale setting from lattice QCD: We give a determination of the phenomenological value of the Wilson (or\ngradient) flow scales t0 and w0 for 2+1 flavours of dynamical quarks. The\nsimulations are performed keeping the average quark mass constant, which allows\nthe approach to the physical point to be made in a controlled manner. O(a)\nimproved clover fermions are used and together with four lattice spacings this\nallows the continuum extrapolation to be taken."
    },
    {
        "anchor": "Cutoff Effects on Energy-Momentum Tensor Correlators in Lattice Gauge\n  Theory: We investigate the discretization errors affecting correlators of the\nenergy-momentum tensor $T_{\\mu\\nu}$ at finite temperature in SU($N_c$) gauge\ntheory with the Wilson action and two different discretizations of\n$T_{\\mu\\nu}$. We do so by using lattice perturbation theory and\nnon-perturbative Monte-Carlo simulations. These correlators, which are\nfunctions of Euclidean time $x_0$ and spatial momentum ${\\bf p}$, are the\nstarting point for a lattice study of the transport properties of the gluon\nplasma. We find that the correlator of the energy $\\int d^3x T_{00}$ has much\nlarger discretization errors than the correlator of momentum $\\int d^3x\nT_{0k}$. Secondly, the shear and diagonal stress correlators ($T_{12}$ and\n$T_{kk}$) require $\\Nt\\geq 8$ for the $Tx_0={1/2}$ point to be in the scaling\nregion and the cutoff effect to be less than 10%. We then show that their\ndiscretization errors on an anisotropic lattice with $\\as/\\at=2$ are comparable\nto those on the isotropic lattice with the same temporal lattice spacing.\nFinally, we also study finite ${\\bf p}$ correlators.",
        "positive": "Relevance of the axial anomaly at the finite-temperature chiral\n  transition in QCD: We investigate the nature of the finite-temperature chiral transition in QCD\nwith two light flavors, in the case of an effective suppression of the the\nU(1)_A symmetry breaking induced by the axial anomaly, which implies the\nsymmetry breaking U(2)_L X U(2)_R -> U(2)_V, instead of SU(2)_L X SU(2)_R ->\nSU(2)_V. For this purpose, we perform a high-order field-theoretical\nperturbative study of the renormalization-group (RG) flow of the corresponding\nthree-dimensional multiparameter Landau-Ginzburg-Wilson Phi4 theory with the\nsame symmetry-breaking pattern. We confirm the existence of a stable fixed\npoint (FP), and determine its attraction domain in the space of the bare\nquartic parameters. Therefore, the chiral QCD transition might be continuous\nalso if the U(1)_A symmetry is effectively restored at Tc. However, the\ncorresponding universality class differs from the O(4) vector universality\nclass which would describe a continuous transition in the presence of a\nsubstantial U(1)_A symmetry breaking at Tc. We estimate the critical exponents\nof the U(2)_L X U(2)_R -> U(2)_V universality class by computing and analyzing\ntheir high-order perturbative expansions. These results are important to\ndiscriminate among the different scenarios for the scaling behavior of QCD with\ntwo light flavors close to the chiral transition."
    },
    {
        "anchor": "Isocliny in spinor space and Wilson fermions: We show that Clifford algebras are closely related to the study of isoclinic\nsubspaces of spinor spaces and, consequently, to the Hurwitz-Radon matrix\nproblem. Isocliny angles are introduced to parametrize gamma matrices, i.e.,\nmatrix representations of the generators of finite-dimensional Clifford\nalgebras C(m,n). Restricting the consideration to the Clifford algebra C(4,0),\nthis parametrization is then applied to the study of Dirac traces occurring in\nEuclidean lattice quantum field theory within the hopping parameter expansion\nfor Wilson fermions.",
        "positive": "Logarithmic link smearing for full QCD: A Lie-algebra based recipe for smoothing gauge links in lattice field theory\nis presented, building on the matrix logarithm. With or without hypercubic\nnesting, this LOG/HYL smearing yields fat links which are differentiable w.r.t.\nthe original ones. This is essential for defining UV-filtered (\"fat link\")\nfermion actions which may be simulated with a HMC-type algorithm. The effect of\nthis smearing on the distribution of plaquettes and on the residual mass of\ntree-level O(a)-improved clover fermions in quenched QCD is studied."
    },
    {
        "anchor": "Kaon matrix elements in domain-wall QCD with DBW2 gauge action: We present calculations of the decay constants and kaon B-parameter $B_K$ as\nthe first stage of RBC Collaboration's quenched numerical simulations using\nDBW2 gauge action and domain-wall fermions. Some of potential systematic errors\nand consistency to previous works are discussed.",
        "positive": "Medium effects and parity doubling of hyperons across the deconfinement\n  phase transition: We analyse the behaviour of hyperons with strangeness $S=-1$,$-2$,$-3$ in the\nhadronic and quark gluon plasma phases, with particular interest in parity\ndoubling and its emergence as the temperature grows. This study uses our\nFASTSUM anisotropic $N_f\\!\\!=$~2+1 ensembles, with four temperatures below and\nfour above the deconfinement transition temperature, $T_c$. The positive-parity\ngroundstate masses are found to be largely temperature independent below $T_c$,\nwhereas the negative-parity ones decrease considerably as the temperature\nincreases. Close to the transition, the masses are almost degenerate, in line\nwith the expectation from chiral symmetry restoration. This may be of interest\nfor heavy-ion phenomenology. In particular we show an application of this\neffect to the Hadron Resonance Gas model. A clear signal of parity doubling is\nfound above $T_c$ in all hyperon channels, with the strength of the effect\ndepending on the number of $s$-quarks in the baryons."
    },
    {
        "anchor": "Infrared Yang-Mills theory as a spin system. A lattice approach: To verify the conjecture that Yang-Mills theory in the infrared limit is\nequivalent to a spin system whose excitations are knot solitons, a numerical\nalgorithm based on the inverse Monte Carlo method is proposed. To investigate\nthe stability of the effective spin field action, numerical studies of the\nrenormalization group flow for the coupling constants are suggested. A\nuniversality of the effective spin field action is also discussed.",
        "positive": "Roper Resonance in 2+1 Flavor QCD: The low-lying even-parity states of the nucleon are explored in lattice QCD\nusing the PACS-CS collaboration 2+1-flavor dynamical-QCD gauge-field\nconfigurations made available through the International Lattice Datagrid\n(ILDG). The established correlation-matrix approach is used, in which various\nfermion source and sink smearings are utilized to provide an effective basis of\ninterpolating fields to span the space of low-lying energy eigenstates. Of\nparticular interest is the nature of the first excited state of the nucleon,\nthe $N{1/2}^{+}$ Roper resonance of $P_{11}$ pion-nucleon scattering. The Roper\nstate of the present analysis approaches the physical mass, displaying\nsignificant chiral curvature at the lightest quark mass. These full QCD\nresults, providing the world's first insight into the nucleon mass spectrum in\nthe light-quark regime, are significantly different from those of quenched QCD\nand provide interesting insights into the dynamics of QCD."
    },
    {
        "anchor": "Chiral symmetry breaking in (2+1) dimensional QED: We study dynamical mass generation in QED in (2+1) dimensions using\nHamiltonian lattice methods. We use staggered fermions, and perform simulations\nwith explicit dynamical fermions in the chiral limit. We demonstrate that a\nrecently developed method to reduce the fermion sign problem can successfully\nbe applied to this problem. Our results are in agreement with both the strong\ncoupling expansion and with Euclidean lattice simulations.",
        "positive": "Second Order Perturbation Theory for Improved Gluon and Staggered Quark\n  Actions: We present the results of our perturbative calculations of the static quark\npotential, small Wilson loops, the static quark self energy, and the mean link\nin Landau gauge. These calculations are done for the one loop Symanzik improved\ngluon action, and the improved staggered quark action."
    },
    {
        "anchor": "First order phase transitions of spin systems: I review some numerical ways to determine the parameters of systems close to\na first order phase transition point: energy and specific heat of the\ncoexisting phases and interface tension. Numerical examples are given for the\n2-d $q$ states Potts model.",
        "positive": "Nucleon Axial Form Factors from Clover Fermion on 2+1+1-flavor HISQ\n  Lattice: The nucleon axial form factors -- axial $G_A$, induced pseudoscalar\n$\\widetilde{G}_P$ and pseudoscalar $G_P$ -- have displayed large systematics in\nlattice QCD calculations. The major symptoms were the violation of the\npartially conserved axial current (PCAC) relation between the three form\nfactors, and the underestimation of the induced pseudoscalar coupling\n$g_P^\\ast$ and the axial charge radius $r_A$ compared to phenomenological\nestimates. The small $g_P^\\ast$ was a consequence of the failure of the\npion-pole dominance (PPD) hypothesis, especially at low $M_\\pi^2$. The small\ncharge radius $r_A$ and the underestimate of $g_A$ were related. The dominant\nsystematic responsible is the lack of inclusion of low-energy ($N \\pi$) states\nthat are not manifest in the multiexponential fit to the nucleon two-point\ncorrelator. We show that this low-energy state can be determined from the\nthree-point correlator $\\langle N A_4 N \\rangle $ with the insertion of the\ntemporal component of the axial current $A_4$ within the nucleon state, ie, the\nstrategy labeled $S_{A4}$ [1]. Including this low-energy state in fits to\ncontrol excited-state contamination (ESC) gives results for $g_A$, $r_A$, and\n$g_P^\\ast$ that are consistent with experimental/phenomenological values.\nHowever, the systematic uncertainties, especially in data at small $Q^2$, are\nnow much larger."
    },
    {
        "anchor": "Progress on charm semileptonic form factors from 2+1 flavor lattice QCD: Lattice calculations of the form factors for the charm semileptonic decays D\nto K l nu and D to pi l nu provide inputs to direct determinations of the CKM\nmatrix elements |V(cs)| and |V(cd)| and can be designed to validate\ncalculations of the form factors for the bottom semileptonic decays B to pi l\nnu and B to K l l-bar. We are using Fermilab charm (bottom) quarks and asqtad\nstaggered light quarks on the 2+1 flavor asqtad MILC ensembles to calculate the\ncharm (bottom) form factors. We outline improvements to the previous\ncalculation of the charm form factors and detail our progress. We expect our\ncurrent round of data production to allow us to reduce the theoretical\nuncertainties in |V(cs)| and |V(cd)| from 10.5% and 11%, respectively, to about\n7%.",
        "positive": "Valence parton distribution function of pion from fine lattice: We present a lattice QCD study of valence parton distribution inside the pion\nwithin the framework of Large Momentum Effective Theory. We use a mixed action\napproach with 1-HYP smeared valence Wilson clover quarks on 2+1 flavor HISQ sea\nwith the valence quark mass tuned to 300 MeV pion mass. We use $48^3 \\times 64$\nlattice at a fine lattice spacing $a=0.06$ fm for this computation. We\nrenormalize the quasi-PDF matrix element in the non-perturbative RI-MOM scheme.\nAs a byproduct, we test the validity of 1-loop matching procedure by comparing\nthe RI-MOM renormalized quasi-PDF matrix element with off-shell quark external\nstates as computed in the continuum 1-loop perturbation theory with the lattice\nresults at $a=0.04$ and 0.06 fm. By applying the RI-MOM to ${\\bar{\\rm MS}}$\none-loop matching, implemented through a fit to phenomenologically motivated\nPDFs, we obtain the valence PDF of pion."
    },
    {
        "anchor": "Chiral anomalies in the reduced model: On the basis of an observation due to Kiskis, Narayanan and Neuberger, we\nshow that there is a remnant of chiral anomalies in the reduced model when a\nDirac operator which obeys the Ginsparg-Wilson relation is employed for the\nfermion sector. We consider fermions belonging to the fundamental\nrepresentation of the gauge group U(N) or SU(N). For vector-like theories, we\ndetermine a general form of the axial anomaly or the topological charge within\na framework of a U(1) embedding. For chiral gauge theories with the gauge group\nU(N), a remnant of gauge anomaly emerges as an obstruction to a smooth fermion\nintegration measure. The pure gauge action of gauge-field configurations which\ncause these non-trivial phenomena always diverges in the 't Hooft $N\\to\\infty$\nlimit when d>2.",
        "positive": "On the definition of the covariant lattice Dirac operator: In the continuum the definitions of the covariant Dirac operator and of the\ngauge covariant derivative operator are tightly intertwined. We point out that\nthe naive discretization of the gauge covariant derivative operator is related\nto the existence of local unitary operators which allow the definition of a\nnatural lattice gauge covariant derivative. The associated lattice Dirac\noperator has all the properties of the classical continuum Dirac operator, in\nparticular antihermiticy and chiral invariance in the massless limit, but is of\ncourse non-local in accordance to the Nielsen-Ninomiya theorem. We show that\nthis lattice Dirac operator coincides in the limit of an infinite lattice\nvolume with the naive gauge covariant generalization of the SLAC derivative,\nbut contains non-trivial boundary terms for finite-size lattices. Its numerical\ncomplexity compares pretty well on finite lattices with smeared lattice Dirac\noperators."
    },
    {
        "anchor": "Calculation of Nucleon Electric Dipole Moments Induced by Quark\n  Chromo-Electric Dipole Moments: We present initial results of computing nucleon electric dipole moment\ninduced by quark chromo-EDM, CP-violating quark-gluon coupling. Using\nchirally-symmetric domain wall and M\\\"obius fermions with pion mass\n$m_\\pi=172\\text{ MeV}$, we calculate the connected part of the electric dipole\nform factor $F_3(Q^2)$. In addition, we perform an exploratory study of the\nmethod to calculate EDM using uniform background electric field on a lattice\nintroduced without breaking the periodicity in the time direction.",
        "positive": "B spectroscopy with NRQCD and HISQ: Using NRQCD b quarks and HISQ light, strange and charm quarks we have\ncalculated B meson masses and B^*-B splittings. We quote results for a range of\nlattice spacings and sea quark masses, enabling controlled extrapolation to the\nphysical point. Since the $b$ quark masses and lattice spacing are fixed from\nthe \\Upsilon and other meson masses, this allows accurate, parameter-free tests\nof B, B_s, and B_c masses against experiment. We can also predict the mass of\nthe B^*_c meson."
    },
    {
        "anchor": "Inhomogeneous Phases in the Chiral Gross-Neveu Model on the Lattice: We discuss possible existence of inhomogeneous phase in low temperature and\nhigh density region in the 1+1 dimensional chiral Gross-Neveu ( $\\chi$GN$_2$ )\nmodel on the lattice. First we investigate the phase structure of the\n$\\chi$GN$_2$ model at vanishing chemical potential, changing temperature. From\nbehavior of $\\Delta^2 = \\Sigma^2 + \\Pi^2$ as a function of Monte Carlo time, a\ncandidate of an order parameter for chiral symmetry in the $\\chi$GN$_2$ model\nis $\\Delta$. At vanishing chemical potential, we observe restoration of chiral\nsymmetry at high $T$. In low temperature and high chemical potential region, we\nfind existence of inhomogeneous phase in spatial correlation functions of\n$\\sigma$ and $\\pi$. The signal of inhomogeneous phase in correlation function\nof $\\Delta$ is more clearly than that of $\\sigma$ or $\\pi$.",
        "positive": "Hybrid static potentials from Laplacian Eigenmodes: We present a method for computing hybrid static quark-antiquark potentials in\nlattice QCD based on Laplace trial states. They are formed by eigenvector\ncomponents of the covariant lattice Laplace operator and their covariant\nderivatives. The new method does not need complicated gauge link paths between\nthe static quarks and makes off-axis separations easily accessible. We show\nfirst results for $\\Sigma$ and $\\Pi$ together with their excited states on a\ndynamical ensemble."
    },
    {
        "anchor": "Distance between configurations in MCMC simulations and the geometrical\n  optimization of the tempering algorithms: For a given Markov chain Monte Carlo (MCMC) algorithm, we define the distance\nbetween configurations that quantifies the difficulty of transitions. This\ndistance enables us to investigate MCMC algorithms in a geometrical way, and we\ninvestigate the geometry of the simulated tempering algorithm implemented for\nan extremely multimodal system with highly degenerate vacua. We show that the\nlarge scale geometry of the extended configuration space is given by an\nasymptotically anti-de Sitter metric, and argue in a simple, geometrical way\nthat the tempering parameter should be best placed exponentially to acquire\nhigh acceptance rates for transitions in the extra dimension. We also discuss\nthe geometrical optimization of the tempered Lefschetz thimble method, which is\nan algorithm towards solving the numerical sign problem.",
        "positive": "Nucleon strange quark content in 2+1-flavor QCD: We calculate the strange quark content of the nucleon directly from its\ndisconnected three-point function in N_f=2+1 QCD. Chiral symmetry is crucial to\navoid a possibly large contamination due to operator mixing, and is exactly\npreserved by employing the overlap quark action. We also use the all-to-all\nquark propagator and the low-mode averaging technique in order to accurately\ncalculate the relevant nucleon correlator. Our preliminary result extrapolated\nto the physical point is f_{T_s} = 0.013(12)(16). This is in good agreement\nwith our previous estimate in N_f=2 QCD as well as those from our indirect\ncalculations using the Feynman-Hellmann theorem."
    },
    {
        "anchor": "Perturbative renormalization factors for generic $\u0394s=2$ four-quark\n  operators in domain-wall QCD with improved gauge action: We calculate one-loop renormalization factors of generic DeltaS=2 four-quark\noperators for domain-wall QCD with the plaquette gauge action and the Iwasaki\ngauge action. The renormalization factors are presented in the modified minimal\nsubtraction (MS-bar) scheme with the naive dimensional regularization. As an\nimportant application we show how to construct the renormalization factors for\nthe operators contributing to K^0-K^0bar mixing in the supersymmetric models\nwith the use of our results.",
        "positive": "An Analysis of the Hadronic Spectrum from Lattice QCD: I begin by discussing the basic ideas of quantum field theory (QFT). I\nprovide a review of symmetries in physics and then move on to discuss the quark\nmodel. I then review lattice gauge theory with particular attention paid to\nlattice QCD and some of the associated problems. I discuss gauge fields on the\nlattice along with free lattice fermions. I follow this with a definition of\nthe lattice QCD action and discuss how to reproduce the correct continuum\nphysics. I include a discussion of the basic numerical techniques employed in\nlattice simulations. I review methods for putting particles onto the lattice\nand describe how to fit the resulting data. The symmetries of the QCD\nLagrangian are reviewed along with various forms of symmetry breaking in\nphysics, the PCAC relation, the Goldberger-Treiman relation and the spontaneous\nbreakdown of the axial symmetry. I move on to discuss sigma models and finally\narrive at a basic chiral perturbation theory. I present research completed with\nmy supervisor C. Allton and collaborators A.W. Thomas, D.B. Leinweber and R.\nYoung in the final three chapters. This work involves making lattice\npredictions for the Hadronic mass spectrum using extrapolation techniques based\non the predictions of chiral perturbation theory which have been developed by\nthe Adelaide group."
    },
    {
        "anchor": "Eigenvalue spectrum of lattice $\\mathcal{N}=4$ super Yang-Mills: We present preliminary results for the eigenvalue spectrum of\nfour-dimensional ${\\cal N}=4$ super Yang-Mills theory on the lattice. In\nparticular, by studying the the spectral density a measurement of the anomalous\ndimension is made and found to be consistent with zero.",
        "positive": "Efficiently unquenching QCD+QED at O($\u03b1$): We outline a strategy to efficiently include the electromagnetic interactions\nof the sea quarks in QCD+QED. When computing iso-spin breaking corrections to\nhadronic quantities at leading order in the electromagnetic coupling, the\nsea-quark charges result in quark-line disconnected diagrams which are\nchallenging to compute precisely. An analysis of the variance of stochastic\nestimators for the relevant traces of quark propagators helps us to improve the\nsituation for certain flavour combinations and space-time decompositions. We\npresent preliminary numerical results for the variances of the corresponding\ncontributions using an ensemble of $N_\\mathrm{f}=2+1$ domain-wall fermions\ngenerated by the RBC/UKQCD collaboration."
    },
    {
        "anchor": "Cost of dynamical quark simulations: O(a) improved Wilson fermions: I report on cost estimates and algorithmic performance in simulations using 2\nflavours of non-perturbatively O(a) improved Wilson quarks together with the\nWilson plaquette action.",
        "positive": "Meson correlators in the epsilon-regime of two-flavor lattice QCD: We calculate the meson correlators in the $\\epsilon$-regime of two-flavor\nQCD. On a $16^3\\times 32$ lattice with $a\\sim 0.11$ fm, the lattice simulations\nare performed with the dynamical overlap fermions. We reduce the sea quark mass\ndown to $\\sim$ 3 MeV and the valence quark masses are taken in the range 1-4\nMeV. The meson correlators in various channels are compared with the\npredictions of (partially quenched) chiral perturbation theory (ChPT).\nIncluding the NLO order of the $\\epsilon$-expansion, we extract the\nleading-order low energy constants of ChPT, the pion decay constant $F$ and the\nchiral condensate $\\Sigma$, as $F=87.3(5.5)$ MeV and\n$\\Sigma^{\\bar{\\mathrm{MS}}}=[237.8(4.0){MeV}]^3$."
    },
    {
        "anchor": "Locally-smeared operator product expansions: We propose a \"locally-smeared Operator Product Expansion\" (sOPE) to decompose\nnon-local operators in terms of a basis of locally-smeared operators. The sOPE\nformally connects nonperturbative matrix elements of smeared degrees of\nfreedom, determined numerically using the gradient flow, to non-local operators\nin the continuum. The nonperturbative matrix elements do not suffer from\npower-divergent mixing on the lattice, provided the smearing scale is kept\nfixed in the continuum limit. The presence of this smearing scale prevents a\nsimple connection to the standard operator product expansion and therefore\nrequires the construction of a two-scale formalism. We demonstrate the\nfeasibility of our approach using the example of real scalar field theory.",
        "positive": "Review of recent highlights in lattice calculations at finite\n  temperature and finite density: I review some recent lattice results on studying chiral and deconfinement\ntransition in QCD at finite temperature and density, as well as properties of\nstrongly interacting matter at high temperatures. I discuss lattice results on\nthe equation of state, fluctuations of conserved charges, chromo-electric\nscreening as well as the determination of the chiral transition temperature."
    },
    {
        "anchor": "The static-light baryon spectrum from twisted mass lattice QCD: We compute the static-light baryon spectrum by means of Wilson twisted mass\nlattice QCD using N_f = 2 flavors of sea quarks. As light u/d valence quarks we\nconsider quarks, which have the same mass as the sea quarks with corresponding\npion masses in the range 340 MeV < m_PS < 525 MeV, as well as partially\nquenched s quarks, which have a mass around the physical value. We consider all\npossible combinations of two light valence quarks, i.e. Lambda, Sigma, Xi and\nOmega baryons corresponding to isospin I = 0, 1/2, 1 and strangeness S = 0, -1,\n-2 as well as angular momentum of the light degrees of freedom j = 0, 1 and\nparity P = +, -. We extrapolate in the light u/d and in the heavy b quark mass\nto the physical point and compare with available experimental results. Besides\nexperimentally known positive parity states we are also able to predict a\nnumber of negative parity states, which have neither been measured in\nexperiments nor previously been computed by lattice methods.",
        "positive": "Study of the topological vacuum structure of SU(2) gluodynamics at T > 0\n  with overlap fermions and improved action: We study SU(2) gluodynamics at finite temperature near the deconfining phase\ntransition. We create the lattice ensembles using the tadpole improved\nLuscher-Weisz action. The overlap Dirac operator is used to determine the\nfollowing three aspects of vacuum structure: (i) The topological susceptibility\nis evaluated at various temperatures across the phase transition, (ii) the\noverlap fermion spectral density is determined and found to depend on the\nPolyakov loop above the phase transition and (iii) the corresponding\nlocalization properties of low lying eigenmodes are investigated."
    },
    {
        "anchor": "On the non-physical concavity of the quark potentials within the thick\n  center vortex model: Lattice gauge theory results show the confinement for the quark potential in\ndifferent Yang-Mills theories and even the G(2) gauge theory. LGT calculations\nshow that quark potential should have the down concavity behavior. Confinement\nproperties can be explained using the thick center vortex model. However an\nupward concavity is seen in the quark potential intervals using this model.\nAfter study the reason of this concavity, it is shown the non physical\nconcavity can be reduced by taking an arbitrary symmetric vortex flux in the\nspace time plane of the lattice.",
        "positive": "Update on the lattice calculation of $B \\to K^* \u03b3$: We summarise our current results for calculations of the form factors for $B\n\\to K^* \\gamma$, and their extrapolation to the physical b-quark mass."
    },
    {
        "anchor": "Critical behavior of 3D SU(2) gauge theory at finite temperature: exact\n  results from universality: We show that universality arguments, namely the Svetitsky-Yaffe conjecture,\nallow one to obtain exact results on the critical behavior of 3D SU(2) gauge\ntheory at the finite temperature deconfinement transition,through a mapping\ninto the 2D Ising model. In particular, we consider the finite-size scaling\nbehavior of the plaquette operator, which can be mapped into the energy\noperator of the 2D Ising model. We obtain exact predictions for the dependence\nof the plaquette expectation value on the size and shape of the lattice and we\ncompare them to Monte Carlo results, finding complete agreement. We discuss the\napplication of this method to the computation of more general correlators of\nthe plaquette operator at criticality, and its relevance to the study of the\ncolor flux tube structure.",
        "positive": "New Universality Classes for Two-Dimensional $\u03c3$-Models: We argue that the two-dimensional $O(N)$-invariant lattice $\\sigma$-model\nwith mixed isovector/isotensor action has a one-parameter family of nontrivial\ncontinuum limits, only one of which is the continuum $\\sigma$-model constructed\nby conventional perturbation theory. We test the proposed scenario with a\nhigh-precision Monte Carlo simulation for $N=3,4$ on lattices up to $512 \\times\n512$, using a Wolff-type embedding algorithm. [CPU time $\\approx$ 7 years IBM\nRS-6000/320H] The finite-size-scaling data confirm the existence of the\npredicted new family of continuum limits. In particular, the $RP^{N-1}$ and\n$N$-vector models do not lie in the same universality class."
    },
    {
        "anchor": "Confirming the Existence of the strong CP Problem in Lattice QCD with\n  the Gradient Flow: We calculate the electric dipole moment of the nucleon induced by the QCD\ntheta term. We use the gradient flow to define the topological charge and use\n$N_f = 2+1$ flavors of dynamical quarks corresponding to pion masses of $700$,\n$570$, and $410$ MeV, and perform an extrapolation to the physical point based\non chiral perturbation theory. We perform calculations at $3$ different lattice\nspacings in the range of $0.07~{\\rm fm} < a < 0.11$ fm at a single value of the\npion mass, to enable control on discretization effects. We also investigate\nfinite size effects using $2$ different volumes. A novel technique is applied\nto improve the signal-to-noise ratio in the form factor calculations. The very\nmild discretization effects observed suggest a continuum-like behavior of the\nnucleon EDM towards the chiral limit. Under this assumption our results read\n$d_{n}=-0.00152(71)\\ \\bar\\theta\\ e~\\text{fm}$ and $d_{p}=0.0011(10)\\\n\\bar\\theta\\ e~\\text{fm}$. Assuming the theta term is the only source of CP\nviolation, the experimental bound on the neutron electric dipole moment limits\n$\\left|\\bar\\theta\\right| < 1.98\\times 10^{-10}$ ($90\\%$ CL). A first attempt at\ncalculating the nucleon Schiff moment in the continuum resulted in $S_{p} =\n0.50(59)\\times 10^{-4}\\ \\bar\\theta\\ e~\\text{fm}^3$ and $S_{n} = -0.10(43)\\times\n10^{-4}\\ \\bar\\theta\\ e~\\text{fm}^3$.",
        "positive": "Tuning improved anisotropic actions in lattice perturbation theory: We discuss the tuning of the anisotropic clover action and Symanzik-improved\ngauge action in lattice perturbation theory. The fermion action is constructed\nfrom stout-smeared spatial links, which complicates the calculation\nconsiderably. In addition, the full quark-mass dependence of the action\nparameters is included in this study. We present results for the fermion and\ngauge aspect ratios for varying bare aspect ratios, quark masses and smearing\nparameters."
    },
    {
        "anchor": "B_s and B_d mixing in full lattice QCD using NRQCD b quarks: We give a progress report on studies of B_s and B_d mixing with valence NRQCD\nb quarks and asqtad light quarks on the MILC configurations including the\neffect of 2+1 flavours of sea quarks. We explore methods for reducing\nstatistical and systematic errors in the ratio \\xi =\nf_{B_s}\\sqrt{B_{B_s}}/f_{B_d}\\sqrt{B_{B_d}}.",
        "positive": "$1^{-+}$ exotic meson at light quark masses: The mass of the $1^{-+}$ exotic meson, created with hybrid interpolating\nfields, is explored at light quark masses approaching 25 MeV ($m_\\pi / m_\\rho\n\\simeq 1/3$). Access to such light quark masses is facilitated by the use of\nthe Fat-Link Irrelevant Clover (FLIC) fermion action. Additionally, we make use\nof large ($20^3 \\times 40$) lattices to obtain good control of statistical and\nfinite volume errors. Our results indicate that the $1^{-+}$ exotic exhibits\nsignificant curvature close the chiral limit, indicating previous linear\nextrapolations, far from the chiral regime, have overestimated the mass of the\n$1^{-+}$. We find for the first time in lattice studies a $1^{-+}$ mass in\nagreement with the $\\pi_1 (1600)$ candidate. We also find a strangeness $\\pm$1\n$J^P = 1^-$ state with a mass close to 2 GeV."
    },
    {
        "anchor": "Non-perturbative formulation of the static color octet potential: By dressing Polyakov lines with appropriate functionals of the gauge fields,\nwe construct observables describing a fundamental representation static\nquark-antiquark pair in the singlet, adjoint and average channels of SU(N) pure\ngauge theory. Each of the potentials represents a gauge invariant eigenvalue of\nthe Hamiltonian. Numerical simulations are performed for SU(2) in 2+1\ndimensions. The adjoint channel is found to be repulsive at small and confining\nat large separations, suggesting the existence of a metastable (N^2-1)-plet\nbound state. For small distances and temperatures above the deconfinement\ntransition, the leading order perturbative prediction for the ratio of singlet\nand adjoint potentials is reproduced by the lattice data.",
        "positive": "Smooth interpolation of lattice gauge fields by signal processing\n  methods: We digitally filter the Fourier modes of the link angles of an abelian\nlattice gauge field which produces the Fourier modes of a continuum $A_\\mu(x)$\nthat exactly reproduces the lattice links through their definition as phases of\nfinite parallel transport. The constructed interpolation is smooth\n($C^\\infty$), free from transition functions, and gauge equivariant. After\ndiscussing some properties of this interpolation, we discuss the non-abelian\ngeneralization of the method, arriving for SU(2), at a Cayley parametrization\nof the links in terms of the Fourier modes of $A^c_\\mu(x)$. We then discuss the\nuse of a maximum entropy type method to address gauge invariance in the\nnon-abelian case."
    },
    {
        "anchor": "Absence of Parity-Flavor Breaking Phase in QCD with two Flavors of\n  Wilson fermions for beta greater than or equal to 5.0: We present data testing the existence of a parity-flavor breaking phase in\nsimulations of QCD with two flavors of light Wilson fermions. This is done by\nexplicit simulations on lattice sizes of $6^4$, $8^4$ and $10^4$ for a variety\nof values of $\\beta$ and $\\kappa$ as well as the coefficient, $h$, of an\nexplicit breaking term included in the action. We find that at $\\beta=6/g^2 $\nequal to or greater than 5.0 extrapolation in the parameter $h$ as well as in\nthe lattice volume show no indication of a phase where parity and flavor are\nspontaneously broken in the limit of zero $h$.",
        "positive": "Quark chiral condensate from the overlap quark propagator: From the overlap lattice quark propagator calculated in the Landau gauge, we\ndetermine the quark chiral condensate by fitting operator product expansion\nformulas to the lattice data. The quark propagators are computed on domain wall\nfermion configurations generated by the RBC-UKQCD Collaborations with $N_f=2+1$\nflavors. Three ensembles with different light sea quark masses are used at one\nlattice spacing $1/a=1.75(4)$ GeV. We obtain\n$\\langle\\bar\\psi\\psi\\rangle^{\\overline{\\rm MS}}(2\\mbox{\nGeV})=(-305(15)(21)\\mbox{ MeV})^3$ in the SU(2) chiral limit."
    },
    {
        "anchor": "The BlueGene/L Supercomputer: The architecture of the BlueGene/L massively parallel supercomputer is\ndescribed. Each computing node consists of a single compute ASIC plus 256 MB of\nexternal memory. The compute ASIC integrates two 700 MHz PowerPC 440 integer\nCPU cores, two 2.8 Gflops floating point units, 4 MB of embedded DRAM as cache,\na memory controller for external memory, six 1.4 Gbit/s bi-directional ports\nfor a 3-dimensional torus network connection, three 2.8 Gbit/s bi-directional\nports for connecting to a global tree network and a Gigabit Ethernet for I/O.\n65,536 of such nodes are connected into a 3-d torus with a geometry of\n32x32x64. The total peak performance of the system is 360 Teraflops and the\ntotal amount of memory is 16 TeraBytes.",
        "positive": "Short distance physics with heavy quark potentials: We present lattice studies of heavy quark potentials in the quenched\napproximation of QCD at finite temperatures. Both, the color singlet and color\naveraged potentials are calculated. While the potentials are well known at\nlarge distances, we give a detailed analysis of their short distance behavior\n(from 0.015 fm to 1 fm) near the critical temperature. At these distances we\nexpect that the T-dependent potentials go over into the zero temperature\npotential. Indeed, we find evidences that the temperature influence gets\nsuppressed and the potentials starts to become a unique function of the\nunderlying distance scale. We use this feature to normalize the heavy quark\npotentials at short distances and extract the free energy of the quark system\nin a gluonic heat bath."
    },
    {
        "anchor": "Universal Amplitude Ratios in the 3D Ising Model: We present a high precision Monte Carlo study of various universal amplitude\nratios of the three dimensional Ising spin model. Using state of the art\nsimulation techniques we studied the model close to criticality in both phases.\nGreat care was taken to control systematic errors due to finite size effects\nand correction to scaling terms. We obtain $C_+/C_-=4.75(3)$,\n$f_{+,2nd}/f_{-,2nd}=1.95(2)$ and $u^*=14.3(1)$. Our results are compatible\nwith those obtained by field theoretic methods applied to the $\\phi^4$ theory\nand high and low temperature series expansions of the Ising model. The mismatch\nwith a previous Montecarlo study by Ruge et al. remains to be understood.",
        "positive": "Lattice Perturbation Theory: The consideration of quantum fields defined on a spacetime lattice provides\ncomputational techniques which are invaluable for studying gauge theories\nnonperturbatively from first principles. Perturbation theory is an essential\naspect of computations on the lattice, especially for investigating the\nbehavior of lattice theories near the continuum limit. Particularly important\nis its role in connecting the outcome of Monte Carlo simulations to continuum\nphysical results. For these matchings the calculation of the renormalization\nfactors of lattice matrix elements is required. In this review we explain the\nmain methods and techniques of lattice perturbation theory, focusing on the\ncases of Wilson and Ginsparg-Wilson fermions. We will illustrate, among other\ntopics, the peculiarities of perturbative techniques on the lattice, the use of\ncomputer codes for the analytic calculations and the computation of lattice\nintegrals. Discussed are also methods for the computation of 1-loop integrals\nwith very high precision. The review presents in a pedagogical fashion also\nsome of the recent developments in this kind of calculations. The coordinate\nmethod of L\\\"uscher and Weisz is explained in detail. Also discussed are the\nnovelties that Ginsparg-Wilson fermions have brought from the point of view of\nperturbation theory. Particular emphasis is given throughout the paper to the\nrole of chiral symmetry on the lattice and to the mixing of lattice operators\nunder renormalization. The construction of chiral gauge theories regularized on\nthe lattice, made possible by the recent advances in the understanding of\nchiral symmetry, is also discussed. Finally, a few detailed examples of lattice\nperturbative calculations are presented."
    },
    {
        "anchor": "Fermi point in graphene as a monopole in momentum space: We consider the effective field theory of graphene monolayer with the Coulomb\ninteraction between fermions taken into account. The gauge field in momentum\nspace is introduced. The position of the Fermi point coincides with the\nposition of the corresponding monopole. The procedure of extracting such\nmonopoles during lattice simulations is suggested.",
        "positive": "Multi-Grid Monte Carlo via $XY$ Embedding I. General Theory and\n  Two-Dimensional $O(N)$-Symmetric Nonlinear $\u03c3$-Models: We introduce a variant of the multi-grid Monte Carlo (MGMC) method, based on\nthe embedding of an $XY$ model into the target model, and we study its\nmathematical properties for a variety of nonlinear $\\sigma$-models. We then\napply the method to the two-dimensional $O(N)$-symmetric nonlinear\n$\\sigma$-models (also called $N$-vector models) with $N=3,4,8$ and study its\ndynamic critical behavior. Using lattices up to $256 \\times 256$, we find\ndynamic critical exponents $z_{int,{\\cal M}^2} \\approx 0.70 \\pm 0.08$, $0.60\n\\pm 0.07$, $0.52 \\pm 0.10$ for $N=3,4,8$, respectively (subjective 68\\%\nconfidence intervals). Thus, for these asymptotically free models, critical\nslowing-down is greatly reduced compared to local algorithms, but not\ncompletely eliminated; and the dynamic critical exponent does apparently vary\nwith $N$. We also analyze the static data for $N=8$ using a finite-size-scaling\nextrapolation method. The correlation length $\\xi$ agrees with the four-loop\nasymptotic-freedom prediction to within $\\approx 1\\%$ over the interval $12 <\n\\xi < 650$."
    },
    {
        "anchor": "The factorization method for systems with a complex action -a test in\n  Random Matrix Theory for finite density QCD-: Monte Carlo simulations of systems with a complex action are known to be\nextremely difficult. A new approach to this problem based on a factorization\nproperty of distribution functions of observables has been proposed recently.\nThe method can be applied to any system with a complex action, and it\neliminates the so-called overlap problem completely. We test the new approach\nin a Random Matrix Theory for finite density QCD, where we are able to\nreproduce the exact results for the quark number density. The achieved system\nsize is large enough to extract the thermodynamic limit. Our results provide a\nclear understanding of how the expected first order phase transition is induced\nby the imaginary part of the action.",
        "positive": "Exact calculation of disconnected loops: We present an implementation of the disconnected diagram contributions to\nquantities such as the flavor-singlet pseudoscalar meson mass which are\naccelerated by GPGPU technology utilizing the NVIDIA CUDA platform. To enable\nthe exact evaluation of the disconnected loops we use a $16^3 \\times 32$\nlattice and $N_f=2$ Wilson fermions simulated by the SESAM Collaboration. The\ndisconnected loops are also computed using stochastic methods with several\nnoise reduction techniques.\n  In particular, we analyze various dilution schemes as well as the recently\nproposed truncated s olver method. We find consistency among the different\nmethods used for the determination of the $\\eta^\\prime$ mass, albeit that the\ngauge noise for the ensemble studied is large. We also find that the effect of\n'dilution' d oes not go beyond that of optimal statistical noise in many cases.\nIt has been observed, however, that spin dilution does have a significant\neffect for some quantities studied."
    },
    {
        "anchor": "Finite-Temperature Phase Structure of Lattice QCD with the Wilson Quark\n  Action for Two and Four Flavors: We present further analyses of the finite-temperature phase structure of\nlattice QCD with the Wilson quark action based on spontaneous breakdown of\nparity-flavor symmetry. Results are reported on (i) an explicit demonstration\nof spontaneous breakdown of parity-flavor symmetry beyond the critical line,\n(ii) phase structure and order of chiral transition for the case of $N_f=4$\nflavors, and (iii) approach toward the continuum limit.",
        "positive": "Charged pion electric polarizability from four-point functions in\n  lattice QCD: Polarizabilities reveal valuable information on the internal structure of\nhadrons in terms of charge and current distributions. For neutral hadrons, the\nstandard approach is the background field method. But for a charged hadron, its\nacceleration under the applied field complicates the isolation of the\npolarization energy. In this work, we explore an alternative method based on\nfour-point functions in lattice QCD. The approach offers a transparent picture\non how polarizabilities arise from photon, quark, and gluon interactions. We\ncarry out a proof-of-concept simulation on the electric polarizability of a\ncharged pion, using quenched Wilson action on a $24^3\\times 48$ lattice at\n$\\beta=6.0$ with pion mass from 1100 to 370 MeV. We show in detail the\nevaluation and analysis of the four-point correlation functions and report\nresults on charge radius and electric polarizability. Our results from\nconnected diagrams suggest that charged pion $\\alpha_E$ is due to a\ncancellation between elastic and inelastic contributions. It would be\ninteresting to see how the cancellation plays out at smaller pion masses in\nfuture simulations."
    },
    {
        "anchor": "The Anti-Ferromagnetic Vacuum: Certain effective vertices may generate a non-homogeneous, periodic vacuum\nstructure. The excitations above such a vacuum are studied in the framework of\nthe $\\phi^4$ and gauge models. The formation of the non-homogeneous vacuum is\naccompanied by the dynamical breakdown of the space-time inversion symmetry.\nChiral transformation is introduced for bosons in close analogy with lattice\nfermions.",
        "positive": "Physical and unphysical effects in the mixed SU(2)/SO(3) gauge theory: We investigate possible problems with universality in lattice gauge theory\nwhere a mixed fundamental SU(2) and SO(3)-invariant gauge group is used: the\n(second order) finite temperature phase transition becomes involved with first\norder effects with increased SO(3) coupling, and this first order effect has a\nnoticeable coupling dependence for small lattices. We produce evidence that the\nfirst order transition is essentially bulk in nature as generally believed, and\nthat the finite temperature effects start to separate out from the lower end of\nthe bulk effects for a lattice of 8 sites in the finite temperature direction.\nWe strengthen our picture of the first order effects as artefacts by using an\nimproved action: this shifts the end point of the first order line away from\nthe fundamental SU(2) axis."
    },
    {
        "anchor": "Quark mass dependence of the low-lying charmed mesons at one loop in\n  HH$\u03c7$PT: We study the light and heavy quark mass dependence of the low-lying charmed\nmesons in the framework of one-loop HH$\\chi$PT. The low energy constants are\ndetermined by analyzing the available lattice data from different LQCD\nsimulations. Model selection tools are implemented to determine the relevant\nparameters as required by data with a higher precision. Discretization and\nother effects due to the charm quark mass setting are discussed.",
        "positive": "Extracting the Single-Particle Gap in Carbon Nanotubes with Lattice\n  Quantum Monte Carlo: We show how lattice Quantum Monte Carlo simulations can be used to calculate\nelectronic properties of carbon nanotubes in the presence of strong\nelectron-electron correlations. We employ the path integral formalism and use\nmethods developed within the lattice QCD community for our numerical work and\ncompare our results to empirical data of the Anti-Ferromagnetic Mott Insulating\ngap in large diameter tubes."
    },
    {
        "anchor": "A Study of Symmetry Restoration at Finite Temperature in the O(4) Model\n  Using Anisotropic Lattices: Results of investigations of the O(4) spin model at finite temperature using\nanisotropic lattices are presented. In both the large $N$ approximation and the\nnumerical simulations using the Wolff cluster algorithm we find that the ratio\nof the symmetry restoration temperature $T_{\\rm SR}$ to the Higgs mass $m_{\\rm\nH}$ is independent of the anisotropy. We obtain a lower bound of $0.59 \\pm\n0.04$ for the ratio, $T_{\\rm SR}/m_{\\rm H}$, at $m_{\\rm H}a \\simeq 0.5$, which\nis lowered further by about 10% at $m_{\\rm H}a \\simeq 1.$",
        "positive": "Fisher zeros and RG flows for $SU(3)$ with $N_f$ flavors: We calculate the Fisher zeros for $SU(3)$ gauge theory with different $N_f$\nflavors of staggered fermions for various values of the fermion mass. We\ndiscuss the finite-size scaling near the end point of the line of discontinuity\nof $\\bar{\\psi} \\psi$ in the beta-mass plane and in the larger beta-lower mass\nregion. We discuss possible interpretations of these results in terms of\nWilsonian RG flows and their possible relevance to construct composite Higgs\nmodels."
    },
    {
        "anchor": "Expansion coefficient of the pseudo-scalar density using the gradient\n  flow in lattice QCD: We use the Yang-Mills gradient flow to calculate the pseudo-scalar expansion\ncoefficient $c_P^*(t_f)$. This quantity is a key ingredient to obtaining the\nchiral condensate and strange quark content of the nucleon using the Lattice\nQCD formulation, which can ultimately determine the spin independent (SI)\nelastic cross section of dark matter models involving WIMP-nucleon\ninteractions. The goal, using the gradient flow, is to renormalize the chiral\ncondensate and the strange content of the nucleon without a power divergent\nsubtraction. Using Chiral symmetry and the small flow time expansion of the\ngradient flow, the scalar density at zero flow time can be related to the\npseudo-scalar density at non zero flow time. By computing the flow time\ndependance of the pseudo-scalar density over multiple lattices box sizes,\nlattice spacings and pion masses, we can obtain the scalar density of the\nnucleon. Our lattice ensembles are $N_{f}=2+1$, PCAC-CS gauge field\nconfigurations, varying over $m_{\\pi}\\approx \\{410,570,700\\}$~MeV at\n$a=0.0907$~fm, with additional ensembles that vary $a\\approx\n\\{0.1095,0.0936,0.0684\\} $~fm at $m_{\\pi} \\approx 700$~MeV.",
        "positive": "Two-flavour lattice QCD correlation functions in the deconfinement\n  transition region: We report on a lattice QCD calculation with two dynamical flavors of the\nisovector vector correlator in the high-temperature phase. We analyze the\ncorrelator in terms of the associated spectral function by performing a fit for\nthe difference of the thermal and vacuum spectral functions, using also an\nexact sum rule that constrains this difference. Additonally we carry out a\ndirect fit for the thermal spectral function, and obtain good agreement between\nthe two analyses for frequencies below the two-pion threshold. Under the\nassumption that the spectral function is smooth in that region, we give an\nestimate of the electrical conductivity."
    },
    {
        "anchor": "Accelerating Lattice QCD Multigrid on GPUs Using Fine-Grained\n  Parallelization: The past decade has witnessed a dramatic acceleration of lattice quantum\nchromodynamics calculations in nuclear and particle physics. This has been due\nto both significant progress in accelerating the iterative linear solvers using\nmulti-grid algorithms, and due to the throughput improvements brought by GPUs.\nDeploying hierarchical algorithms optimally on GPUs is non-trivial owing to the\nlack of parallelism on the coarse grids, and as such, these advances have not\nproved multiplicative. Using the QUDA library, we demonstrate that by exposing\nall sources of parallelism that the underlying stencil problem possesses, and\nthrough appropriate mapping of this parallelism to the GPU architecture, we can\nachieve high efficiency even for the coarsest of grids. Results are presented\nfor the Wilson-Clover discretization, where we demonstrate up to 10x speedup\nover present state-of-the-art GPU-accelerated methods on Titan. Finally, we\nlook to the future, and consider the software implications of our findings.",
        "positive": "Domain walls, $Z(N)$ charge and $A_0$ condensate: a canonical ensemble\n  study: The deconfinement phase transition is studied in the ensemble canonical with\nrespect to triality. Since this ensemble implies a projection to the zero\ntriality sector of the theory we introduce a quantity which is insensitive to\n$Z(N_c)$ symmetry but can reveal a critical behaviour in the theory with\ndynamical quarks. Further, we argue that in the canonical ensemble description\nof full QCD there exist domains of different $Z(N_c)$ phases which are\ndegenerate and possess normal physical properties. This contradicts the\npredictions of the grand canonical ensemble. We propose a new order parameter\nto test the realization of the discrete $Z(N_c)$ symmetry at finite temperature\nand calculate it for the case of $Z(2)$ gauge fields coupled to fundamental\nfermions."
    },
    {
        "anchor": "Gauge-equivariant flow models for sampling in lattice field theories\n  with pseudofermions: This work presents gauge-equivariant architectures for flow-based sampling in\nfermionic lattice field theories using pseudofermions as stochastic estimators\nfor the fermionic determinant. This is the default approach in state-of-the-art\nlattice field theory calculations, making this development critical to the\npractical application of flow models to theories such as QCD. Methods by which\nflow-based sampling approaches can be improved via standard techniques such as\neven/odd preconditioning and the Hasenbusch factorization are also outlined.\nNumerical demonstrations in two-dimensional U(1) and SU(3) gauge theories with\n$N_f=2$ flavors of fermions are provided.",
        "positive": "Centre Vortices in the Presence of Dynamical Fermions: The behaviour of centre vortices in the presence of dynamical fermions is\nstudied for the first time in the context of the static quark potential and the\nLandau-gauge gluon propagator. These results indicate that in the presence of\ndynamical fermions, centre vortices are able to better encapsulate the\nlong-range behaviour of QCD, compared to previous studies on pure Yang-Mills\nlattices. This work provides strong evidence that centre vortices are\nresponsible for the long-range linear potential and the enhanced infrared gluon\npropagator, which are indicative of confinement in QCD."
    },
    {
        "anchor": "The Eta-prime Meson with Staggered Fermions: We have computed the eta-prime pseudoscalar octet mass splitting using\nstaggered fermions on both dynamical and quenched gauge configurations. We have\nused Wuppertal smeared operators to reduce excited state contributions. We\ncompare our results with the theoretical forms predicted by partially quenched\nchiral perturbation theory in the lowest order. Using lattice volumes of size\n16^3 x 32 with a^{-1}=2GeV we obtain results consistent with the physical\neta-prime mass. We also demonstrate that the flavor singlet piece of the\neta-prime mass comes from zero modes of the Dirac operator.",
        "positive": "'t Hooft tensor for generic gauge group: We study monopoles in gauge theories with generic gauge group. Magnetic\ncharges are in one-to-one correspondence with the second homotopy classes at\nspatial infinity (${\\Pi}_2$), which are therefore identified by the 't Hooft\ntensor. We determine the 't Hooft tensor in the general case. These issues are\nrelevant to the understanding of Color Confinement."
    },
    {
        "anchor": "Gluon propagators and center vortices in gluon plasma: We study electric and magnetic components of the gluon propagators in\nquark-gluon plasma in terms of center vortices by using a quenched simulation\nof SU(2) lattice theory. In the Landau gauge, the magnetic components of the\npropagators are strongly affected in the infrared region by removal of the\ncenter vortices, while the electric components are almost unchanged by this\nprocedure. In the Coulomb gauge, the time-time correlators, including an\ninstantaneous interaction, also have an essential contribution from the center\nvortices. As a result, one finds that magnetic degrees of freedom in the\ninfrared region couple strongly to the center vortices in the deconfinement\nphase.",
        "positive": "Perturbative study for domain-wall fermions in 4+1 dimensions: We investigate a U(1) chiral gauge model in 4+1 dimensions formulated on the\nlattice via the domain-wall method. We calculate an effective action for smooth\nbackground gauge fields at a fermion one loop level. From this calculation we\ndiscuss properties of the resulting 4 dimensional theory, such as gauge\ninvariance of 2 point functions, gauge anomalies and an anomaly in the fermion\nnumber current."
    },
    {
        "anchor": "Magnetic field on lattice U(1)-Higgs and SU(2)xU(1)-Higgs theories: External (hyper)magnetic field can modify the phase structure in U(1)\ngauge+Higgs (Landau-Ginzburg) and SU(2)xU(1) gauge+Higgs (Standard Model)\ntheories. In this talk I discuss how the magnetic field can be implemented on\nthe lattice, and summarize the effects on symmetry breaking phase transitions.",
        "positive": "Energy shift of the three-particle system in a finite volume: Using the three-particle quantization condition recently obtained in the\nparticle-dimer framework, the finite-volume energy shift of the two lowest\nthree-particle scattering states is derived up to and including order $L^{-6}$.\nFurthermore, assuming that a stable dimer exists in the infinite volume, the\nshift for the lowest particle-dimer scattering state is obtained up to and\nincluding order $L^{-3}$. The result for the lowest three-particle state agrees\nwith the results from the literature, and the result for the lowest\nparticle-dimer state reproduces the one obtained by using the Luescher\nequation."
    },
    {
        "anchor": "Hadron spin structure from lattice QCD: We present results on the spin carried by quarks and gluons in the nucleon\nusing lattice QCD simulations with physical values of the light, strange and\ncharm quark masses. We also discuss selective results on the x-dependence of\nparton distribution functions computed in lattice QCD employing the\nquasi-parton distribution approach and the large momentum effective theory.",
        "positive": "Electromagnetic matrix elements for negative parity nucleons: Here we present preliminary results for the evaluation of the electromagnetic\nform factors for the lowest-lying negative-parity, spin-$\\frac{1}{2}$ nucleons,\nnamely the $S_{11}(1535)$ and $S_{11}(1650)$, through the use of the\nvariational method. We find that the characteristics of the electric form\nfactor, $G_{E}$, are similar between these states, however significant\ndifferences are observed between the quark-sector contributions to the magnetic\nform factor, $G_{M}$. Within simple constituent quark models, these states are\nunderstood to be admixtures of $s=\\frac{1}{2}$ and $s=\\frac{3}{2}$ states\ncoupled to orbital angular momentum $\\ell = 1$. Our results reveal a\nqualitative difference in the manner in which the singly-represented quark\nsector contributes to these baryon magnetic form factors."
    },
    {
        "anchor": "Extended investigation of the twelve-flavor $\u03b2$-function: We report new results from high precision analysis of an important BSM gauge\ntheory with twelve massless fermion flavors in the fundamental representation\nof the SU(3) color gauge group. The range of the renormalized gauge coupling is\nextended from our earlier work {Fodor:2016zil} to probe the existence of an\ninfrared fixed point (IRFP) in the $\\beta$-function reported at two different\nlocations, originally in {Cheng:2014jba} and at a new location in\n{Hasenfratz:2016dou}. We find no evidence for the IRFP of the $\\beta$-function\nin the extended range of the renormalized gauge coupling, in disagreement with\n{Cheng:2014jba,Hasenfratz:2016dou}. New arguments to guard the existence of the\nIRFP remain unconvincing {Hasenfratz:2017mdh}, including recent claims of an\nIRFP with ten massless fermion flavors {Chiu:2016uui,Chiu:2017kza} which we\nalso rule out. Predictions of the recently completed 5-loop QCD\n$\\beta$-function for general flavor number are discussed in this context.",
        "positive": "Flavor Singlet Axial Vector Coupling of the Proton with Dynamical Wilson\n  Fermions: We present the results of a full QCD lattice calculation of the flavor\nsinglet axial vector coupling $G_A^1$ of the proton. The simulation has been\ncarried out on a $16^3\\times 32$ lattice at $\\beta=5.6$ with $n_f=2$ dynamical\nWilson fermions. It turns out that the statistical quality of the connected\ncontribution to $G_A^1$ is excellent, whereas the disconnected part is\naccessible but suffers from large statistical fluctuations. Using a 1st order\ntadpole improved renormalization constant $Z_A$, we estimate $G_A^1 =\n0.20(12)$."
    },
    {
        "anchor": "Kaon-kaon scattering at maximal isospin from $N_f=2+1+1$ twisted mass\n  lattice QCD: We present results for the interaction of two kaons at maximal isospin. The\ncalculation is based on 2+1+1 flavour gauge configurations generated by the ETM\nCollaboration (ETMC) featuring pion masses ranging from about 230 MeV to 450\nMeV at three values of the lattice spacing. The elastic scattering length\n$a_0^{I=1}$ is calculated at several values of the bare strange quark and light\nquark masses. We find $M_K a_0 =-0.397(11)(_{-8}^{+0})$ as the result of a\nchiral and continuum extrapolation to the physical point. This number is\ncompared to other lattice results.",
        "positive": "Finite Temperature Transitions in Lattice QCD with Wilson Quarks ---\n  Chiral Transitions and the Influence of the Strange Quark ---: The nature of finite temperature transitions in lattice QCD with Wilson\nquarks is studied near the chiral limit for the cases of 2, 3, and 6 flavors of\ndegenerate quarks ($N_F=2$, 3, and 6) and also for the case of massless up and\ndown quarks and a light strange quark ($N_F=2+1$). Our simulations mainly\nperformed on lattices with the temporal direction extension $N_t=4$ indicate\nthat the finite temperature transition in the chiral limit (chiral transition)\nis continuous for $N_F=2$, while it is of first order for $N_F=3$ and 6. We\nfind that the transition is of first order for the case of massless up and down\nquarks and the physical strange quark where we obtain a value of\n$m_\\phi/m_\\rho$ consistent with the physical value. We also discuss the phase\nstructure at zero temperature as well as that at finite temperatures."
    },
    {
        "anchor": "Constructing a composite Higgs model with built-in large separation of\n  scales: Experimentally the existence of a light 125 GeV Higgs boson is well\nestablished but so far no other heavier resonances have been observed. Viable\nmodels to describe the Higgs boson as composite particle require hence to\nexhibit a large separation of scales. This occurs naturally in systems located\nnear a conformal fixed point irrespective whether the system lies outside or\ninside the conformal window. We demonstrate the latter case by investigating a\nmass-split model with four light and six heavy flavors. By construction\nmass-split models exhibit a large separation of scales and feature in addition\na highly constrained hadron spectrum. We present results based on the low-lying\nconnected meson spectrum. Although the light sector is chirally broken, we show\nthat it exhibits hyperscaling which is typical for conformal systems.",
        "positive": "The strange and charm quark contributions to the anomalous magnetic\n  moment of the muon from lattice QCD: We describe a new technique (published in Phys. Rev. D89 114501) to determine\nthe contribution to the anomalous magnetic moment of the muon coming from the\nhadronic vacuum polarisation using lattice QCD. Our method uses Pad\\'e\napproximants to reconstruct the Adler function from its derivatives at $q^2=0$.\nThese are obtained simply and accurately from time-moments of the vector\ncurrent-current correlator at zero spatial momentum. We test the method using\nstrange quark correlators calculated on MILC Collaboration's $n_f = 2+1+1$ HISQ\nensembles at multiple values of the lattice spacing, multiple volumes and\nmultiple light sea quark masses (including physical pion mass configurations).\nWe find the (connected) contribution to the anomalous moment from the strange\nquark vacuum polarisation to be $a^s_\\mu=53.41(59)\\times 10^{-10}$, and the\ncontribution from charm quarks to be $a^c_\\mu=14.42(39)\\times 10^{-10}$ - 1%\naccuracy is achieved for the strange quark contribution. The extension of our\nmethod to the light quark contribution and to that from the quark-line\ndisconnected diagram is straightforward."
    },
    {
        "anchor": "Strangeness and glue in the nucleon from lattice QCD: We study the strangeness contribution to nucleon matrix elements using Nf=2+1\ndynamical clover fermion configurations generated by the CP-PACS/JLQCD\ncollaboration. In order to evaluate the disconnected insertion (DI), we use the\nZ(4) stochastic method, along with unbiased subtraction from the hopping\nparameter expansion which reduces the off-diagonal noises in the stochastic\nmethod. Furthermore, we find that using many nucleon sources for each\nconfiguration is effective in improving the signal. Our results for the quark\ncontribution to the first moment <x>_q in the DI, and the strangeness magnetic\nmoment show that the statistical errors are under control with these\ntechniques. We also study the gluonic contribution to the nucleon using the\noverlap operator to construct the gauge field tensor, F_{mu,nu}. The\napplication to the calculation of first moment, <x>_G, gives a good signal in\nquenched lattice QCD.",
        "positive": "Improving the dynamical overlap algorithm: We present algorithmic improvements to the overlap Hybrid Monte Carlo\nalgorithm, including preconditioning techniques and improvements to the\ncorrection step, used when one of the eigenvalues of the Kernel operator\nchanges sign, which is now O(\\Delta t^2) exact."
    },
    {
        "anchor": "Absence of chiral symmetry breaking in multi-flavor strongly coupled\n  lattice gauge theories: We consider lattice gauge theories at strong coupling with gauge group\n$U(N_C)$, or $SU(N_C)$ restricted to the meson sector, and coupled to $N_F$\nflavors of fundamental representation staggered fermions. We study the\nformation of a chiral condensate by means of resummation of a hopping\nexpansion. Different classes of graphs become dominant as the parameter\n$(N_F/N_C)$ is varied. By performing graph resummation we obtain an equation\nfor determining the condensate as a function of $(N_F/N_C)$ and mass $m$. For\nvalues of $(N_F/N_C)$ below a critical value one reproduces the well-known\nresult of the existence of a non-vanishing condensate solution in the $m=0$\nlimit. Above the critical $(N_F/N_C)$ value, however, no such solution exists,\nits abrupt disappearance indicating a first order transition to a chirally\nsymmetric phase with composite (colorless) excitation spectrum.",
        "positive": "Heavy-light Mesons and Baryons with b quarks: We present lattice results for the spectrum of mesons containing one heavy\nquark and of baryons containing one or two heavy quarks. The calculation is\ndone in the quenched approximation using the NRQCD formalism for the heavy\nquark. We analyze the dependence of the mass splittings on both the heavy and\nthe light quark masses. Meson P-state fine structure and baryon hyperfine\nsplittings are resolved for the first time. We fix the b quark mass using both\nM_B and M_{\\Lambda_b}, and our best estimate is m_b^\\MSbar(m_b^\\MSbar) =\n4.35(10)({}^{-3}_{+2})(10) GeV. The spectrum, obtained by interpolation to m_b,\nis compared with the experimental data."
    },
    {
        "anchor": "K_l3 form factor with N_f=2+1 dynamical domain wall fermions: A progress\n  report: We present the latest results from the UKQCD/RBC collaborations for the K_l3\nform factor with 2+1 flavours of dynamical domain wall quarks. Simulations are\nperformed on 16^3x32x16 and 24^3x64x16 lattices with three values of the light\nquark mass, allowing for an extrapolation to the chiral limit. After\ninterpolating to zero momentum transfer, we obtain the preliminary result\nf_+^{K\\pi}(0)=0.9609(51) (or \\Delta f = -0.0161(51)), which is in agreement\nwith the result of Leutwyler & Roos.",
        "positive": "Metadynamics Surfing on Topology Barriers in the Schwinger Model: Topological freezing is a well known problem in lattice simulations: with\nshrinking lattice spacing a transition between topological sectors becomes\nincreasingly improbable, leading to a problematic increase of the\nautocorrelation time regarding several observables. We present our\ninvestigation of metadynamics as a solution for topological freezing in the\nSchwinger model. Specifically, we take a closer look at the collective variable\nand its scaling behaviour, visualize the effects of topological freezing and\nhow metadynamics helps in that respect and explore alternatives for a more\nefficient building process. Possible implications for and differences to\nfour-dimensional SU(3) theory are briefly discussed."
    },
    {
        "anchor": "Closed flux tubes in D=2+1 SU(N) gauge theories: dynamics and effective\n  string description: We extend our earlier calculations of the spectrum of closed flux tubes in\nSU(N) gauge theories in 2+1 dimensions, with a focus on questions raised by\nrecent theoretical progress on the effective string action of long flux tubes\nand the world-sheet action for flux tubes of moderate lengths. Our new\ncalculations in SU(4) and SU(8) provide evidence that the leading O(1/l^gamma)\nnon-universal correction to the flux tube ground state energy does indeed have\na power gamma greater than or equal to 7. We perform a study in SU(2), where we\ncan traverse the length at which the Nambu-Goto ground state becomes tachyonic,\nto obtain an all-N view of the spectrum. Our comparison of the k=2 flux tube\nexcitation energies in SU(4) and SU(6) suggests that the massive world sheet\nexcitation associated with the k=2 binding has a scale that knows about the\ngroup and hence the theory in the bulk, and we comment on the potential\nimplications of world sheet massive modes for the bulk spectrum. We provide a\nquantitative analysis of the surprising (near-)orthogonality of flux tubes\ncarrying flux in different SU(N) representations, which implies that their\nscreening by gluons is highly suppressed even at small N.",
        "positive": "The QCD equation of state at finite density from analytical continuation: We determine the equation of state of QCD at finite chemical potential, to\norder $(\\mu_B/T)^6$, for a system of 2+1 quark flavors. The simulations are\nperformed at the physical mass for the light and strange quarks on several\nlattice spacings; the results are continuum extrapolated using lattices of up\nto $N_t=16$ temporal resolution. The QCD pressure and interaction measure are\ncalculated along the isentropic trajectories in the $(T,~\\mu_B)$ plane\ncorresponding to the RHIC Beam Energy Scan collision energies. Their behavior\nis determined through analytic continuation from imaginary chemical potentials\nof the baryonic density. We also determine the Taylor expansion coefficients\naround $\\mu_B=0$ from the simulations at imaginary chemical potentials.\nStrangeness neutrality and charge conservation are imposed, to match the\nexperimental conditions."
    },
    {
        "anchor": "Modified Mean Field approximation for the Ising Model: We study a modified mean-field approximation for the Ising Model in arbitrary\ndimension. Instead of taking a \"central\" spin, or a small \"drop\" of fluctuating\nspins coupled to the effective field of their nearest neighbors as in the\nMean-Field or the Bethe-Peierls-Weiss methods, we take an infinite chain of\nfluctuating spins coupled to the mean field of the rest of the lattice. This\nresults in a significative improvement of the Mean-Field approximation with a\nsmall extra effort.",
        "positive": "Regulated chiral gauge theories: Noncompact chiral abelian gauge theories are defined on the lattice using the\noverlap formalism. The main definitions are presented, the role of anomaly\ncancelation is discussed, and the triviality issue in four dimensions is\nexplained."
    },
    {
        "anchor": "Spin models on Platonic solids and asymptotic freedom: We consider a two-dimensional sigma-model with discrete\nicosahedral/dodecahedral symmetry. We present high-precision finite-size\nnumerical results that show that the continuum limit of this model is different\nfrom the continuum limit of the rotationally invariant O(3) sigma-model.",
        "positive": "Lattice Study of Dense Matter with Two Colors and Four Flavors: We present results from a simulation of SU(2) lattice gauge theory with N_f=4\nflavors of Wilson fermion and non-zero quark chemical potential mu, using the\nsame 12^3x24 lattice, bare gauge coupling, and pion mass in cut-off units as a\nprevious study with N_f=2. The string tension for N_f=4 is found to be\nconsiderably smaller implying smoother gauge field configurations.\nThermodynamic observables and order parameters for superfluidity and color\ndeconfinement are studied, and comparisons drawn between the two theories.\nResults for quark density and pressure as functions of mu are qualitatively\nsimilar for N_f=2 and N_f=4; in both cases there is evidence for a phase in\nwhich baryonic matter is simultaneously degenerate and confined. Results for\nthe stress-energy tensor, however, suggest that while N_f=2 has a regime where\ndilute matter is non-relativistic and weakly-interacting, N_f=4 matter is\nrelativistic and strongly-interacting for all values of mu above onset."
    },
    {
        "anchor": "Hamiltonian effective field theory in elongated or moving finite volume: We extend previous work concerning rest-frame partial-wave mixing in\nHamiltonian effective field theory to both elongated and moving systems, where\ntwo particles are in a periodic elongated cube or have nonzero total momentum,\nrespectively. We also consider the combination of the two systems when\ndirections of the elongation and the moving momentum are aligned. This\nextension should also be applicable in any Hamiltonian formalism. As a\ndemonstration, we analyze lattice QCD results for the spectrum of an isospin-2\n$\\pi\\pi$ scattering system and determine the $s$, $d$, and $g$ partial-wave\nscattering information. The inclusion of lattice simulation results from moving\nframes significantly improves the uncertainty in the scattering information.",
        "positive": "Supercurrent conservation in the lattice Wess-Zumino model with\n  Ginsparg-Wilson fermions: We study supercurrent conservation for the four-dimensional Wess-Zumino model\nformulated on the lattice. The formulation is one that has been discussed\nseveral times, and uses Ginsparg-Wilson fermions of the overlap (Neuberger)\nvariety, together with an auxiliary fermion (plus superpartners), such that a\nlattice version of U(1)_R symmetry is exactly preserved in the limit of\nvanishing bare mass. We show that the almost naive supercurrent is conserved at\none loop. By contrast we find that this is not true for Wilson fermions and a\ncanonical scalar action. We provide nonperturbative evidence for the\nnonconservation of the supercurrent in Monte Carlo simulations."
    },
    {
        "anchor": "Towards a determination of the nucleon EDM from the quark chromo-EDM\n  operator with the gradient flow: In this proceedings, we lay the foundation for computing the contribution of\nquark chromo-electric dipole moment (qCEDM) operator to the nucleon electric\ndipole moment. By applying the gradient flow technique, we can parameterize the\nrenormalization and operator mixing issues associated with the qCEDM operator\non the lattice. As the nucleon mixing angle $\\alpha_N$ is a key component for\ndetermining the neutron and proton electric dipole moments induced by the qCEDM\noperator, we present the formalism and preliminary results for $\\alpha_N$ with\nrespect to the gradient flow time $t_f$. The results are computed on $N_f=2+1$\nWilson-clover lattices provided by PACS-CS. The 3 ensembles have lattice\nspacing values of $a=\\lbrace 0.1095,\\,0.0936,\\,0.0684\\rbrace $fm, whilst\nkeeping a similar $m_{\\pi}\\approx701$MeV, and a fixed box size of\n$L\\approx1.9$fm.",
        "positive": "Stochastic locality and master-field simulations of very large lattices: In lattice QCD and other field theories with a mass gap, the field variables\nin distant regions of a physically large lattice are only weakly correlated.\nAccurate stochastic estimates of the expectation values of local observables\nmay therefore be obtained from a single representative field. Such master-field\nsimulations potentially allow very large lattices to be simulated, but require\nvarious conceptual and technical issues to be addressed. In this talk, an\nintroduction to the subject is provided and some encouraging results of\nmaster-field simulations of the SU(3) gauge theory are reported."
    },
    {
        "anchor": "Probing TeV scale physics via ultra cold neutron decays and calculating\n  non-standard baryon matrix elements: We motivate undertaking precision analyses of neutron decays to look for\nsignatures of new scalar and tensor interactions that can arise in extensions\nof the Standard Model at the TeV scale. The key ingrediant needed to connect\nexperimental data with theoretical analysis are high-precision calculations of\nmatrix elements of isovector bilinear operators between the decaying neutron\nand final state proton. We describe the status of our Lattice QCD program of\nusing valence clover fermions on dynamical N_f=2+1+1 HISQ configurations\ngenerated by the MILC Collaboration. On the theoretical side we use the\neffective field theory method and provide both model independent and dependent\nanalyses to obtain bounds on possible scalar and tensor interactions, both from\nlow energy experiments and LHC data.",
        "positive": "Quark masses from quenched overlap fermions: We compute light and strange quark masses for quenched overlap fermions at\ntwo values of the gauge coupling. The renormalisation is done\nnon-perturbatively. We test the predictions of quenched chiral perturbation\ntheory for the quark mass dependence of the hadron spectrum and see evidence\nfor the existence of chiral logs."
    },
    {
        "anchor": "Computing the eta and eta' Mesons in Lattice QCD: It has been known for a long time that the large experimental singlet-octet\nmass gap in the pseudoscalar meson mass spectrum originates from the anomaly of\nthe axial vector current, i.e. from nonperturbative effects and the nontrivial\ntopological structure of the QCD vacuum. In the N_colour -> infinity limit of\nthe theory, this connection elucidates in the famous Witten-Veneziano relation\nbetween the eta'-mass and the topological susceptibility of the quenched QCD\nvacuum.While lattice QCD has by now produced impressive high precision results\non the flavour nonsinglet hadron spectrum, the determination of the\npseudoscalar singlet mesons from direct correlator studies is markedly lagging\nbehind, due to the computational complexity in handling observables that\ninclude OZI-rule violating diagrams, like the eta' propagator. In this article,\nwe report on some recent progress in dealing with the numerical bottleneck\nproblem.",
        "positive": "Renormalons on the Lattice and the OPE for the plaquette: a status\n  report: The first ten coefficients in the perturbative expansion of the plaquette in\nLattice SU(3) are computed both on a 8^4 and on a 24^4 lattice. They are shown\nto be fully consistent with the growth dictated by the first IR Renormalon and\nwith the expected finite size effects on top of that. As already pointed out a\nfew years ago, this leads to a puzzling result on the smaller lattice: when the\ncontribution associated with the Renormalon is subtracted from Monte Carlo\nmeasurements of the plaquette, what is left over does not scale (as expected)\nas a^4, but as a^2. While the analysis is not yet complete on the larger\nlattice, the implications of such a finding is discussed."
    },
    {
        "anchor": "Anomalies, gauge field topology, and the lattice: Motivated by the connection between gauge field topology and the axial\nanomaly in fermion currents, I use the fourth power of the naive Dirac operator\nto define a local lattice measure of topological charge. For smooth gauge\nfields this reduces to the usual topological density. For typical gauge field\nconfigurations in a numerical simulation, however, quantum fluctuations\ndominate, and the sum of this density over the system does not generally give\nan integer winding. On cooling with respect to the Wilson gauge action,\ninstanton like structures do emerge. As cooling proceeds, these objects tend\nshrink and finally \"fall through the lattice.\" Modifying the action can block\nthe shrinking at the expense of a loss of reflection positivity. The cooling\nprocedure is highly sensitive to the details of the initial steps, suggesting\nthat quantum fluctuations induce a small but fundamental ambiguity in the\ndefinition of topological susceptibility.",
        "positive": "Sphaleron transition rate in the classical 1+1 dimensional abelian Higgs\n  model at finite temperature: We compute the sphaleron transition rate in the 1+1 dimensional abelian Higgs\nmodel at finite temperature, by real time simulation using the classical\ncanonical ensemble."
    },
    {
        "anchor": "Tuning the Tadpole Improved Clover Wilson Action on Coarse Anisotropic\n  Lattices: Wilson quark action, with tadpole improved clover term added, is studied on\ncoarse anisotropic lattices. The bare velocity of light parameter in this\naction is determined non-perturbatively using the pseudo-scalar and vector\nmeson dispersion relations for various values of the gauge coupling $\\beta$ and\nbare quark mass parameter $\\kappa$.",
        "positive": "Precision tests of the J/\u03c8 from full lattice QCD: mass, leptonic\n  width and radiative decay rate to \u03b7_c: We calculate the J/{\\psi} mass, leptonic width and radiative decay rate to\n\\gamma \\eta_c from lattice QCD including u, d and s quarks in the sea for the\nfirst time. We use the Highly Improved Staggered Quark formalism and\nnonperturbatively normalised vector currents for the leptonic and radiative\ndecay rates. Our results are: M_{J/\\psi} -M_{\\eta_c} = 116.5(3.2) MeV;\n\\Gamma(J/{\\psi} to e^+e^-) = 5.48(16) keV; \\Gamma(J/{\\psi} to \\gamma \\eta_c) =\n2.49(19) keV. The first two are in good agreement with experiment, with\n\\Gamma(J/{\\psi} to e^+e^-) providing a test of a decay matrix element in QCD,\nindependent of CKM uncertainties, to 2%. At the same time results for the time\nmoments of the correlation function can be compared to values from the charm\ncontribution to \\Gamma(e^+e^- to hadrons), giving a 1.5% test of QCD. Our\nresults show that an improved experimental error would enable a similarly\nstrong test from \\Gamma(J/{\\psi} to \\gamma \\eta_c)."
    },
    {
        "anchor": "A Numerical Study of the Hierarchical Ising Model: High Temperature\n  Versus Epsilon Expansion: We study numerically the magnetic susceptibility of the hierarchical model\nwith Ising spins ($\\sigma =\\pm 1$) above the critical temperature and for two\nvalues of the epsilon parameter. The integrations are performed exactly, using\nrecursive methods which exploit the symmetries of the model. Lattices with up\nto $2^18$ sites have been used. Surprisingly, the numerical data can be fitted\nvery well with a simple power law of the form $(1- \\beta /\\beta _c )^{- \\gamma}\n$for the {\\it whole} temperature range. The numerical values for $\\gamma $\nagree within a few percent with the values calculated with a high-temperature\nexpansion but show significant discrepancies with the epsilon-expansion. We\nwould appreciate comments about these results.",
        "positive": "Perspectives in Lattice Gravity: We briefly overview the development of Euclidean quantum gravity in four\ndimensions regarded as a branch of statistical mechanics of discretized random\nmanifolds."
    },
    {
        "anchor": "Nucleon-pion-state contamination in lattice computations of the nucleon\n  electromagnetic form factors: The nucleon-pion-state contributions to QCD two-point and three-point\nfunctions relevant for lattice calculations of the nucleon electromagnetic form\nfactors are studied in chiral perturbation theory. To leading order the results\ndepend on a few experimentally known low-energy constants only, and the\nnucleon-pion-state contribution to the form factors can be estimated. The\nnucleon-pion-state contribution to the electric form factor $G_{\\rm E}(Q^2)$ is\nat the +5 percent level for a source-sink separation of 2 fm, and it increases\nwith increasing momentum transfer $Q^2$. For the magnetic form factor the\nnucleon-pion-state contribution leads to an underestimation of $G_{\\rm M}(Q^2)$\nby about $-5$ percent that decreases with increasing $Q^2$. For smaller\nsource-sink separations that are accessible in present-day lattice simulations\nthe impact is larger. Although the ChPT results may not be applicable for these\ntime separations a comparison with recent lattice data works reasonably well.",
        "positive": "Revisiting glueball wave functions at zero and finite temperature: We study the sizes and thermal properties of glueballs in a three dimensional\ncompact Abelian gauge model on improved lattice. We predict the radii of $\\sim\n0.60$ and $\\sim 1.12$ in the units of string tension, or $\\sim 0.28$ and $\\sim\n0.52$ fm, for the scalar and tensor glueballs, respectively. We perform a well\ncontrolled extrapolation of the radii to the continuum limit and observe that\nour results agree with the predicted values. Using Monte Carlo simulations, we\nextract the pole-mass of the lowest scalar and tensor glueballs from the\ntemporal correlators at finite temperature. We see a clear evidence of the\ndeconfined phase, and the transition appears to be similar to that of the\ntwo-dimensional XY model as expected from universality arguments. Our results\nshow no significant changes in the glueball wave functions and masses in the\ndeconfined phase."
    },
    {
        "anchor": "Schr\u00f6dinger functional boundary conditions and improvement of the\n  SU($N$) pure gauge action for $N>3$: The leading method to study the running coupling constant of non-abelian\ngauge theories is based on the Schr\\\"odinger functional scheme. However, the\nboundary conditions and $\\mathcal{O}(a)$ improvement have not been\nsystematically generalized for theories with more than three colors. These\ntheories have applications in BSM model building as well as in the large $N$\nlimit. We have studied the boundary conditions and improvement for the pure\nYang-Mills theory within the Schr\\\"odinger functional scheme. We have\ndetermined for all values of $N$ the boundary fields which provide high\nsignal/noise ratio. Additionally, we have calculated the improvement\ncoefficient $c_t$ for the pure gauge to one loop order for SU($N$) gauge\ntheories with $N=2,\\ldots,8$ from which $N\\geq 4$ are previously unknown.",
        "positive": "On the order of the QCD chiral phase transition for different numbers of\n  quark flavours: The nature of the QCD chiral phase transition in the limit of vanishing quark\nmasses has remained elusive for a long time, since it cannot be simulated\ndirectly on the lattice and is strongly cutoff-dependent. We report on a\ncomprehensive ongoing study using unimproved staggered fermions with\n$N_\\text{f}\\in[2,8]$ mass-degenerate flavours on $N_\\tau\\in\\{4,6,8\\}$ lattices,\nin which we locate the chiral critical surface separating regions with\nfirst-order transitions from crossover regions in the bare parameter space of\nthe lattice theory. Employing the fact that it terminates in a tricritical\nline, this surface can be extrapolated to the chiral limit using tricritical\nscaling with known exponents. Knowing the order of the transitions in the\nlattice parameter space, conclusions for approaching the continuum chiral limit\nin the proper order can be drawn. While a narrow first-order region cannot be\nruled out, we find initial evidence consistent with a second-order chiral\ntransition in all massless theories with $N_\\text{f}\\leq 6$, and possibly up to\nthe onset of the conformal window at $9\\lesssim N_\\text{f}^*\\lesssim 12$. A\nreanalysis of already published $\\mathcal{O}(a)$-improved $N_\\text{f}=3$ Wilson\ndata on $N_\\tau\\in[4,12]$ is also consistent with tricritical scaling, and the\nassociated change from first to second-order on the way to the continuum chiral\nlimit. We discuss a modified Columbia plot and a phase diagram for many-flavour\nQCD that reflect these possible features."
    },
    {
        "anchor": "Update on $B\\to D^\\ast \\ell \u03bd$ form factor at zero-recoil using the\n  Oktay-Kronfeld action: We present an update on the calculation of $\\bar{B}\\to D^\\ast \\ell \\bar{\\nu}$\nsemileptonic form factor at zero recoil using the Oktay-Kronfeld bottom and\ncharm quarks on $N_f=2+1+1$ flavor HISQ ensembles generated by the MILC\ncollaboration. Preliminary results are given for two ensembles with $a\\approx\n0.12$ and $0.09$ fm and $M_\\pi\\approx 310$ MeV. Calculations have been done\nwith a number of valence quark masses, and the dependence of the form factor on\nthem is investigated on the $a\\approx 0.12$ fm ensemble. The excited state is\ncontrolled by using multistate fits to the three-point correlators measured at\n4--6 source-sink separations.",
        "positive": "Scaling analysis of the O(4)-symmetric $\u03a6^4$-theory in the broken\n  phase: We study the $O(4)$-symmetric $ \\Phi^4 $-theory in the scaling region of the\nbroken phase using the standard and a Symanzik improved action with infinite\nbare self-coupling $\\lambda$. A high precision Monte Carlo simulation is\nperformed by applying the reflection cluster algorithm. Employing the histogram\nmethod we analytically continue to a sequence of values of the hopping\nparameter $\\kappa$ neighbouring the actually simulated ones. In the\ninvestigated vicinity of the critical point $\\kappa_{c}$ finite volume effects\naffecting, e.g., the determination of the field expectation value $\\Sigma$ and\nthe mass $m_\\sigma$ of the $\\sigma$-particle are very well described by 1-loop\nrenormalized perturbation theory. We carry out a detailed scaling analysis on a\nhigh level of precision. Finally we discuss the upper bound on the Higgs mass\nfor both kinds of actions."
    },
    {
        "anchor": "Prepotential formulation of SU(3) lattice gauge theory: The SU(3) lattice gauge theory is reformulated in terms of SU(3) prepotential\nharmonic oscillators. This reformulation has enlarged $SU(3)\\otimes U(1)\n\\otimes U(1)$ gauge invariance under which the prepotential operators transform\nlike matter fields. The Hilbert space of SU(3) lattice gauge theory is shown to\nbe equivalent to the Hilbert space of the prepotential formulation satisfying\ncertain color invariant Sp(2,R) constraints. The SU(3) irreducible prepotential\noperators which solve these Sp(2,R) constraints are used to construct SU(3)\ngauge invariant Hilbert spaces at every lattice site in terms of SU(3) gauge\ninvariant vertex operators. The electric fields and the link operators are\nreconstructed in terms of these SU(3) irreducible prepotential operators. We\nshow that all the SU(3) Mandelstam constraints become local and take very\nsimple form within this approach. We also discuss the construction of all\npossible linearly independent SU(3) loop states which solve the Mandelstam\nconstraints. The techniques can be easily generalized to SU(N).",
        "positive": "Temporal meson correlators at finite temperature on quenched anisotropic\n  lattice: We study charmonium correlators at finite temperature in quenched anisotropic\nlattice QCD. The smearing technique is applied to enhance the low energy part\nof the correlator. We use two analysis procedures: the maximum entropy method\nfor extraction of the spectral function without assuming specific form, as an\nestimate of the shape of spectral function, and the $\\chi^2$ fit assuming\ntypical forms as quantitative evaluation of the parameters associated to the\nforms. We find that at $T\\simeq 0.9T_c$ the ground state peak has almost the\nsame mass as at T=0 and almost vanishing width. At $T\\simeq 1.1T_c$, our result\nsuggests that the correlator still has nontrivial peak structure at almost the\nsame position as below $T_c$ with finite width."
    },
    {
        "anchor": "Kaon semi-leptonic form factor in lattice QCD: This talk reviews recent lattice QCD simulations of the K->pi semi-leptonic\nform factor.",
        "positive": "Chromo-electric screening length in 2+1 flavor QCD: We study Polyakov loop as well as correlators of real and imaginary parts of\nthe Polyakov loop in 2+1 flavor QCD at finite temperature. We use hypercubic\n(HYP) smearing to improve the signal in the lattice calculations and to obtain\nreliable results for the correlators at large distances. From the large\ndistance behavior of the correlators we estimate the chromo-electric screening\nlength to be (0.38-44)/T. Furthermore, we show that the short distance\ndistortions due to HYP smearing do not affect the physics of interest"
    },
    {
        "anchor": "Properties of pseudoscalar flavour-singlet mesons from 2+1+1 twisted\n  mass lattice QCD: We study properties of pseudoscalar flavour-singlet mesons from Wilson\ntwisted mass lattice QCD with Nf=2+1+1 dynamical quark flavors. Results for\nmasses are presented at three values of the lattice spacing and light quark\nmasses corresponding to values of the pion mass from 230 MeV to 500 MeV. We\nbriefly discuss scaling effects and the light and strange quark mass dependence\nof the eta mass. In addition we present an exploratory study using\nOsterwalder-Seiler type strange and charm valence quarks. This approach avoids\nsome of the complications of the twisted mass heavy doublet. We present first\nresults for matching valence and unitary actions and a comparison of\nstatistical uncertainties.",
        "positive": "Observations on discretization errors in twisted-mass lattice QCD: I make a number of observations concerning discretization errors in\ntwisted-mass lattice QCD that can be deduced by applying chiral perturbation\ntheory including lattice artifacts. (1) The line along which the PCAC quark\nmass vanishes in the twisted mass-twisted mass plane makes an angle to the\nuntwisted mass axis which is a direct measure of O(a) terms in the chiral\nLagrangian, and is found numerically to be large; (2) Numerical results for\npionic quantities in the mass plane show the qualitative properties predicted\nby chiral perturbation theory, in particular an asymmetry in slopes between\npositive and negative untwisted quark masses; (3) By extending the description\nof the ``Aoki regime'' (where m_q is of size a^2 Lambda_QCD^3) to\nnext-to-leading order in chiral perturbation theory I show how the phase\ntransition lines and lines of maximal twist (using different definitions)\nextend into this region, and give predictions for the functional form of pionic\nquantities; (4) I argue that the recent claim that lattice artifacts at maximal\ntwist have apparent infrared singularities in the chiral limit results from\nexpanding about the incorrect vacuum state. Shifting to the correct vacuum (as\ncan be done using chiral perturbation theory) the apparent singularities are\nsummed into non-singular, and furthermore predicted, forms. I further argue\nthat there is no breakdown in the Symanzik expansion in powers of lattice\nspacing, and no barrier to simulating at maximal twist in the Aoki regime."
    },
    {
        "anchor": "Nucleon form factors and moments of generalized parton distributions\n  using $N_f=2+1+1$ twisted mass fermions: We present results on the axial and the electromagnetic form factors of the\nnucleon, as well as, on the first moments of the nucleon generalized parton\ndistributions using maximally twisted mass fermions. We analyze two N_f=2+1+1\nensembles having pion masses of 210 MeV and 354 MeV at two values of the\nlattice spacing. The lattice scale is determined using the nucleon mass\ncomputed on a total of 18 N_f=2+1+1 ensembles generated at three values of the\nlattice spacing, $a$. The renormalization constants are evaluated\nnon-perturbatively with a perturbative subtraction of ${\\cal O}(a^2)$-terms.\nThe moments of the generalized parton distributions are given in the $\\bar{\\rm\nMS}$ scheme at a scale of $ \\mu=2$ GeV. We compare with recent results obtained\nusing different discretization schemes. The implications on the spin content of\nthe nucleon are also discussed.",
        "positive": "On the universal critical behavior in 3-flavor QCD: We analyze the universal critical behavior at the chiral critical point in\nQCD with three degenerate quark masses. We confirm that this critical point\nlies in the universality class of the three dimensional Ising model. The\nsymmetry of the Ising model, which is Z(2), is not directly realized in the QCD\nHamiltonian. After making an ansatz for the magnetization- and energy-like\noperators as linear admixtures of the chiral condensate and the gluonic action,\nwe determine several non-universal mixing and normalization constants. These\nparameters determine an unambiguous mapping of the critical behavior in QCD to\nthat of the 3d-Ising model. We verify its validity by showing that the thus\nobtained orderparameter scales in accordance with the magnetic equation of\nstate of the 3d-Ising model."
    },
    {
        "anchor": "News from Lattice QCD on Heavy Quark Potentials and Spectral Functions\n  of Heavy Quark States: We discuss recent lattice results on in-medium properties of hadrons and\nfocus on thermal properties of heavy quark bound states. We will clarify the\nrelation between heavy quark free energies and potentials used to analyze the\nmelting of heavy quark bound states. Furthermore, we present calculations of\nmeson spectral functions which indicate that the charmonium ground states,\nJ/psi and eta_c, persist in the quark gluon plasma as well defined resonances\nwith no significant change of their zero temperature masses at least up to T ~\n1.5 T_c. We also briefly comment on the current status of lattice calculations\nat non-vanishing baryon number density.",
        "positive": "The quenched Eguchi-Kawai model revisited: The motivation and construction of the original Quenched Eguchi-Kawai model\nare reviewed, providing much greater detail than in the first, 1982 QEK paper.\nA 2008 article announced that QEK fails as a reduced model because the average\nover permutations of eigenvalues stays annealed. It is shown here that the\noriginal quenching logic naturally leads to a formulation with no annealed\naverage over permutations."
    },
    {
        "anchor": "Complex wave function, Chiral spin order parameter and Phase Problem: We study the two dimensional Hubbard model by use of the ground state\nalgorithm in the Monte Carlo simulation. We employ complex wave functions as\ntrial function in order to have a close look at properties such as chiral spin\norder ($\\chi$SO) and flux phase. For half filling, a particle-hole\ntransformation leads to sum rules with respect to the Green's functions for a\ncertain choice of a set of wave functions. It is then analytically shown that\nthe sum rules lead to the absence of the $\\chi$SO. Upon doping, we are\nconfronted with the sign problem, which in our case %ch appears as a ``phase\nproblem\" due to the phase of the Monte Carlo weights. The average of the phase\nshows an exponential decay as a function of inverse temperature similarly to\nthat of sign by Loh Jr. et. al. . We compare the numerical results with those\nof exact numerical calculations.",
        "positive": "Chiral measurements with the Fixed-Point Dirac operator and construction\n  of chiral currents: In this preliminary study, we examine the chiral properties of the\nparametrized Fixed-Point Dirac operator D^FP, see how to improve its chirality\nvia the Overlap construction, measure the renormalized quark condensate Sigma\nand the topological susceptibility chi_t, and investigate local chirality of\nnear zero modes of the Dirac operator. We also give a general construction of\nchiral currents and densities for chiral lattice actions."
    },
    {
        "anchor": "Fixed Point Actions for Lattice Fermions: The fixed point actions for Wilson and staggered lattice fermions are\ndetermined by iterating renormalization group transformations. In both cases a\nline of fixed points is found. Some points have very local fixed point actions.\nThey can be used to construct perfect lattice actions for asymptotically free\nfermionic theories like QCD or the Gross-Neveu model. The local fixed point\nactions for Wilson fermions break chiral symmetry, while in the staggered case\nthe remnant $U(1)_e \\otimes U(1)_o$ symmetry is preserved. In addition, for\nWilson fermions a nonlocal fixed point is found that corresponds to free chiral\nfermions. The vicinity of this fixed point is studied in the Gross-Neveu model\nusing perturbation theory.",
        "positive": "Topology of $SU(N)$ lattice gauge theories coupled with $\\mathbb{Z}_N$\n  $2$-form gauge fields: We extend the definition of L\\\"uscher's lattice topological charge to the\ncase of $4$d $SU(N)$ gauge fields coupled with $\\mathbb{Z}_N$ $2$-form gauge\nfields. This result is achieved while maintaining the locality, the $SU(N)$\ngauge invariance, and $\\mathbb{Z}_N$ $1$-form gauge invariance, and we find\nthat the manifest $1$-form gauge invariance plays the central role in our\nconstruction. This result gives the lattice regularized derivation of the mixed\n't Hooft anomaly in pure $SU(N)$ Yang-Mills theory between its $\\mathbb{Z}_N$\n$1$-form symmetry and the $\\theta$ periodicity."
    },
    {
        "anchor": "Investigations on the deconfining phase transition in QCD: We investigate the deconfining phase transition in SU(3) pure gauge theory\nand in full QCD with two flavors of staggered fermions by means of a gauge\ninvariant thermal partition functional. In the pure gauge case our finite size\nscaling analysis is in agreement with the well known weak first order phase\ntransition. In the case of 2 flavors full QCD we find that the phase transition\nis consistent with weak first order, contrary to the expectation of a crossover\nfor not too large quark masses.",
        "positive": "HISQ action in dynamical simulations: We report on recent progress in employing the Highly Improved Staggered Quark\n(HISQ) action introduced by the HPQCD/UKQCD collaboration in simulations with\ndynamical fermions. The HISQ action is an order $a^2$ Symanzik-improved action\nwith further suppressed taste symmetry violations. The improvement in taste\nsymmetry is achieved by introducing Fat7 smearing of the original gauge links\nand reunitarization (projection to an element of U(3) or SU(3)) followed by\nAsq-type smearing. Major challenges for calculating the fermion force are\nrelated to the reunitarization step. We present a preliminary study of the HISQ\naction on two 2+1+1 flavor ensembles with the lattice spacing roughly\nequivalent to the MILC asqtad a=0.125 and 0.09 fm ensembles."
    },
    {
        "anchor": "Nonperturbative determination of the QCD potential at O(1/m): The relativistic correction to the QCD static inter-quark potential at O(1/m)\nis investigated nonperturbatively for the first time by using lattice Monte\nCarlo QCD simulations. The correction is found to be comparable with the\nCoulombic term of the static potential when applied to charmonium, and amounts\nto one-fourth of the Coulombic term for bottomonium.",
        "positive": "Relativistic corrections to the static potential at O(1/m) and O(1/m^2): We investigate the relativistic corrections to the static potential, i.e. the\nO(1/m) potential and the O(1/m^2) velocity-dependent potentials, in SU(3)\nlattice gauge theory. They are important ingredients of potential\nnonrelativistic QCD for heavy quarkonium. Utilizing the multi-level algorithm,\nwe obtain remarkably clean signals of these potentials up to r=0.9 fm. We\nobserve long range nonperturbative contributions to these corrections."
    },
    {
        "anchor": "Identification of shallow two-body bound states in finite volume: We discuss signatures of bound-state formation in finite volume via the\nLuscher finite size method. Assuming that the phase-shift formula in this\nmethod inherits all aspects of the quantum scattering theory, we may expect\nthat the bound-state formation induces the sign of the scattering length to be\nchanged. If it were true, this fact provides us a distinctive identification of\na shallow bound state even in finite volume through determination of whether\nthe second lowest energy state appears just above the threshold. We also\nconsider the bound-state pole condition in finite volume, based on Luscher's\nphase-shift formula and then find that the condition is fulfilled only in the\ninfinite volume limit, but its modification by finite size corrections is\nexponentially suppressed by the spatial lattice size L. These theoretical\nconsiderations are also numerically checked through lattice simulations to\ncalculate the positronium spectrum in compact scalar QED, where the short-range\ninteraction between an electron and a positron is realized in the Higgs phase.",
        "positive": "Heavy Quark Diffusion from 2+1 Flavor Lattice QCD with 320 MeV Pion Mass: We present the first calculations of the heavy flavor diffusion coefficient\nusing lattice QCD with light dynamical quarks. For temperatures\n$195\\,\\mathrm{MeV}<T<352\\,\\mathrm{MeV}$, the heavy quark spatial diffusion\ncoefficient is found to be significantly smaller than previous quenched lattice\nQCD and recent phenomenological estimates. The result implies very fast\nhydrodynamization of heavy quarks in the quark-gluon plasma created during\nultrarelativistic heavy-ion collision experiments."
    },
    {
        "anchor": "K --> pi pi matrix elements from mixed action lattice QCD: We present a new method for determining K --> pi pi matrix elements from\nlattice simulations that is less costly than direct simulations of K --> pi pi\nat physical kinematics. It improves, however, upon the traditional \"indirect''\napproach of constructing the K --> pi pi matrix elements using NLO SU(3) ChPT,\nwhich can lead to large higher-order chiral corrections. Using the explicit\nexample of the Delta I =3/2 (27,1) operator to illustrate the method, we obtain\na value for Re(A_2) that agrees with experiment and has a total uncertainty of\n~20%. Although our simulations use domain-wall valence quarks on the MILC\nasqtad-improved gauge configurations, this method is more general and can be\napplied to calculations with any fermion formulation.",
        "positive": "SU(3) gauge theory with four degenerate fundamental fermions on the\n  lattice: As a part of the project studying large $N_f$ QCD, the LatKMI Collaboration\nhas been investigating the SU(3) gauge theory with four fundamental fermions\n(four-flavor QCD). The main purpose of studying four-flavor QCD is to provide a\nqualitative comparison to $N_f= 8$, $12$, $16$ QCD; however, a quantitative\ncomparison to real-world QCD is also interesting. To make such comparisons more\nmeaningful, it is desirable to use the same kind of lattice action\nconsistently, so that qualitative difference of different theories are less\naffected by artifacts of lattice discretization. Here, we adopt the\nhighly-improved staggered quark action with the tree-level Symanzik gauge\naction (HISQ/tree), which is exactly the same as the setup for our simulations\nfor $SU(3)$ gauge theories with $N_f=8$, $12$ and $16$ fundamental\nfermions~\\cite{Aoki:2013xza, Aoki:2012eq, Aoki:2014oma}. In the next section,\nwe show the fermion mass dependence of $F_\\pi$, $\\langle\\bar{\\psi}\\psi\\rangle$,\n$M_\\pi$, $M_\\rho$, $M_N$ and their chiral extrapolations. In section 3,\npreliminary results of the measurement of the mass of the flavor-singlet scalar\nbound state will be reported."
    },
    {
        "anchor": "Monopole clusters, Z(2) vortices and confinement in SU(2): We extend our previous study of magnetic monopole currents in the maximally\nAbelian gauge [hep-lat/9712003] to larger lattices at small lattice spacings\n(20^4 at beta = 2.5 and 32^4 at beta = 2.5115). We confirm that at these weak\ncouplings there continues to be one monopole cluster that is very much longer\nthan the rest and that the string tension, K, is entirely due to it. The\nremaining clusters are compact objects whose population as a function of radius\nfollows a power law that deviates from the scale invariant form, but much too\nweakly to suggest a link with the analytically calculable size distribution of\nsmall instantons. We also search for traces of Z(2) vortices in the Abelian\nprojected fields; either as closed loops of `magnetic' flux or through\nappropriate correlations amongst the monopoles. We find, by direct calculation,\nthat there is no confining condensate of such flux loops. We also find, through\nthe calculation of doubly charged Wilson loops within the monopole fields, that\nthere is no suppression of the q=2 effective string tension out to at distances\nof at least r ~ 1.6/sqrt{K}, suggesting that if there are any vortices they are\nnot encoded in the monopole fields.",
        "positive": "Improved Overlap Fermions: We test exact and approximate Ginsparg-Wilson fermions with respect to their\nchiral and scaling behavior in the 2-flavor Schwinger model. We first consider\nexplicit approximate GW fermions in a short range, then we proceed to their\nchiral correction by means of the ``overlap formula'', and finally we discuss a\nnumerically efficient perturbative chiral correction. In this way we combine\nvery good chiral and scaling properties with a relatively modest computational\neffort."
    },
    {
        "anchor": "Charmonium Spectrum on dynamical anisotropic lattices: We present a first study of the charmonium spectrum on N_f=2 dynamical,\nanisotropic lattices. We take advantage of all-to-all quark propagators to\nbuild spatially extended interpolating operators to increase the overlap with\nstates not easily accessible with point propagators such as radially excited\nstates of eta_c, psi, and chi_c, D-waves and hybrid states.",
        "positive": "Glueball-Like Screening Masses in Pure SU(3) at Finite Temperatures: We investigate the finite-temperature excitation spectrum in the gluon sector\nof $SU(3)$ pure gauge theory through measurements of screening masses in\ncorrelations of loop operators. We develop the classification of such operators\nunder the symmetry group of the `$z$-slice'. In the confined phase of the\ntheory, we find that the spectrum dynamically realises the zero temperature\nsymmetries. We observe a large thermal shift of the $0^{++}$ glueball mass. In\nthe deconfined phase, the spectrum distinguishes between operators coupling to\nelectrically and magnetically polarised gluon fields. The former yields a\nscreening mass equal to the Wilson-line screening mass; the latter, a method\nfor the measurement of the magnetic mass in the high-temperature limit."
    },
    {
        "anchor": "Excitations of single-beauty hadrons: In this work we study the predominantly orbital and radial excitations of\nhadrons containing a single heavy quark. We present meson and baryon mass\nsplittings and ratios of meson decay constants (e.g., $f_{B_s}/f_B$ and\n$f_{B_s'}/f_{B_s}$) resulting from quenched and dynamical two-flavor\nconfigurations. Light quarks are simulated using the chirally improved (CI)\nlattice Dirac operator at valence masses as light as $M_\\pi \\approx 350$ MeV.\nThe heavy quark is approximated by a static propagator, appropriate for the $b$\nquark on our lattices ($1/a \\sim 1-2$ GeV). We also include some preliminary\ncalculations of the $O(1/m_Q^{})$ kinetic corrections to the states, showing,\nin the process, a viable way of applying the variational method to three-point\nfunctions involving excited states. We compare our results with recent\nexperimental findings.",
        "positive": "The thermal photon emissivity at the QCD chiral crossover from imaginary\n  momentum correlators: The thermal photon emissivity at the QCD chiral crossover is investigated\nusing imaginary momentum correlators. These have been measured on a newly\ngenerated $20 \\times 96^3$ lattice-QCD ensemble with $\\mathcal{O}(a)$-improved\nWilson quarks and physical up, down and strange quark masses at a temperature\n$T=154$\\,MeV near the pseudo-critical temperature. In order to realize the\nphoton on-shell condition, the spatially transverse Euclidean correlators have\nto be evaluated at imaginary spatial momenta. Employing a bounding method, we\npresent a preliminary result on the quantity $H_E(\\omega_1)$, which corresponds\nto an energy-moment of the photon spectral function $\\sigma(\\omega)/\\omega$\ndefined by the weight function $1/(\\omega^2+\\omega_n^2)$, the $\\omega_n$ being\ninteger multiples of $2\\pi T$."
    },
    {
        "anchor": "Topological Aspect of Abelian Projected SU(2) Lattice Gauge Theory: We show that the hypothesis of abelian dominance allows QCD-monopoles to\npreserve the topological feature of the QCD vacuum within SU(2) lattice gauge\ntheory. An analytical study is made to find the relationship between the\ntopological charge and QCD-monopoles in the lattice formulation. The\ntopological charge is explicitly represented in terms of the monopole current\nand the abelian component of gauge fields in the abelian dominated system. We\nnumerically examine the relation and demonstrate the abelian dominance in the\ntopological structure by using Monte Carlo simulation.",
        "positive": "SU(3) gauge theory at finite temperature in 2 + 1 dimensions: In this article we will discuss numerical results on screening masses and\nthermodynamic quantities in 2 + 1 dimensional SU(3) gauge theory. We will also\ncompare them to perturbation theory and the dimensionally reduced model."
    },
    {
        "anchor": "Statistical mechanics of vortices from field theory: We study with lattice Monte Carlo simulations the interactions and\nmacroscopic behaviour of a large number of vortices in the 3-dimensional U(1)\ngauge+Higgs field theory, in an external magnetic field. We determine\nnon-perturbatively the (attractive or repelling) interaction energy between two\nor more vortices, as well as the critical field strength H_c, the\nthermodynamical discontinuities, and the surface tension related to the\nboundary between the Meissner phase and the Coulomb phase in the type I region.\nWe also investigate the emergence of vortex lattice and vortex liquid phases in\nthe type II region. For the type I region the results obtained are in\nqualitative agreement with mean field theory, except for small values of H_c,\nwhile in the type II region there are significant discrepancies. These findings\nare relevant for superconductors and some models of cosmic strings, as well as\nfor the electroweak phase transition in a magnetic field.",
        "positive": "Towards the continuum limit of nucleon form factors at the physical\n  point using lattice QCD: We present results for the axial charge and root-mean-square (RMS) radii of\nthe nucleon obtained from 2+1 flavor lattice QCD at the physical point with a\nlarge spatial extent of about 10 fm. Our calculations are performed with the\nPACS10 gauge configurations generated by the PACS Collaboration with the six\nstout-smeared $O(a)$ improved Wilson-clover quark action and Iwasaki gauge\naction at $\\beta$ = 1.82 and 2.00 corresponding to lattice spacings of 0.085 fm\nand 0.063 fm respectively. We first evaluate the value of $g_A/g_V$ , which is\nnot renormalized in the continuum limit and thus ends up with the renormalized\naxial charge. Moreover, we also calculate the nucleon elastic form factors and\ndetermine three kinds of isovector RMS radii such as electric, magnetic and\naxial ones at the two lattice spacings. We finally discuss the discretization\nuncertainties on renormalized axial charge and isovector RMS radii towards the\ncontinuum limit."
    },
    {
        "anchor": "Investigation of the tetraquark candidate $a_0(980)$: technical aspects\n  and preliminary results: We discuss technical aspects and first results of a lattice QCD study of the\n$a_0(980)$ state. We employ various interpolating operators of quark-antiquark,\nmesonic molecule, diquark-antidiquark and two-meson type. Both connected and\ndisconnected contributions including diagrams with closed fermion loops are\ncomputed. To keep statistical errors small, it is essential to optimize the\ncomputation of these diagrams by choosing that combination of techniques most\nappropriate for each type of diagram from the correlation matrix of\ninterpolating operators. We illustrate, how this can be done, by discussing\ncertain diagrams in detail. We also present preliminary results corresponding\nto a $4\\times 4$ submatrix computed with 2+1 flavors of clover fermions.",
        "positive": "Real Representation in Chiral Gauge Theories on the Lattice: The Weyl fermion belonging to the real representation of the gauge group\nprovides a simple illustrative example for L\\\"uscher's gauge-invariant lattice\nformulation of chiral gauge theories. We can explicitly construct the fermion\nintegration measure globally over the gauge-field configuration space in the\narbitrary topological sector; there is no global obstruction corresponding to\nthe Witten anomaly. It is shown that this Weyl formulation is equivalent to a\nlattice formulation based on the Majorana (left--right-symmetric) fermion, in\nwhich the fermion partition function is given by the Pfaffian with a definite\nsign, up to physically irrelevant contact terms. This observation suggests a\nnatural relative normalization of the fermion measure in different topological\nsectors for the Weyl fermion belonging to the complex representation."
    },
    {
        "anchor": "Scaling analysis of FLIC fermion actions: The Fat Link Irrelevant Clover (FLIC) fermion action is a variant of the\n$O(a)$-improved Wilson action where the irrelevant operators are constructed\nusing smeared links. While the use of such smearing allows for the use of\nhighly improved definitions of the field strength tensor $F_{\\mu\\nu},$ we show\nthat the standard 1-loop clover term with a mean field improved coefficient\n$c_{\\rm sw}$ is sufficient to remove the $O(a)$ errors, avoiding the need for\nnon-perturbative tuning. This result enables efficient dynamical simulations in\nQCD with the FLIC fermion action.",
        "positive": "Do we understand the unquenched value of fB?: I review our qualitative understanding of the increase in the value of the B\nmeson decay constant (fB), when dynamical fermions are included in lattice QCD\ncalculations."
    },
    {
        "anchor": "The chiral and deconfinement aspects of the QCD transition: We present results on the chiral and deconfinement properties of the QCD\ntransition at finite temperature. Calculations are performed with 2+1 flavors\nof quarks using the p4, asqtad and HISQ/tree actions. Lattices with temporal\nextent N_tau=6, 8 and 12 are used to understand and control discretization\nerrors and to reliably extrapolate estimates obtained at finite lattice\nspacings to the continuum limit. The chiral transition temperature is defined\nin terms of the phase transition in a theory with two massless flavors and\nanalyzed using O(N) scaling fits to the chiral condensate and susceptibility.\nWe find consistent estimates from the HISQ/tree and asqtad actions and our main\nresult is T_c=154 +/- 9 MeV.",
        "positive": "Net-baryon number fluctuations in (2+1)-flavor QCD: We present a lattice study of net-baryon number fluctuations in (2+1)-flavor\nQCD. The results are based on a Taylor expansion of the pressure with respect\nto the baryon chemical potential. We calculate higher moments of the net-baryon\nnumber fluctuations and compare with the corresponding resonance gas results.\nWe find that for temperature below 0.9T_c the fluctuations seem to agree with\nthe hadron resonance gas predictions. Close to T_c, higher moments are\nincreasingly more sensitive to the critical behavior of the QCD phase\ntransition. Furthermore, we estimate the radius of convergence of the Taylor\nseries as well as the curvature of the transition line in the temperature\nchemical potential plane."
    },
    {
        "anchor": "Supersymmetric QCD on the Lattice: Fine-Tuning of the Yukawa Couplings: We determine the fine-tuning of the Yukawa couplings of supersymmetric QCD,\ndiscretized on a lattice. We use perturbation theory at one-loop level. The\nModified Minimal Subtraction scheme ($\\overline{{\\rm MS}}$) is employed; by its\ndefinition, this scheme requires perturbative calculations, in the continuum\nand/or on the lattice. On the lattice, we utilize the Wilson formulation for\ngluon, quark and gluino fields; for squark fields we use na\\\"ive\ndiscretization. The sheer difficulties of this study lie in the fact that\ndifferent components of squark fields mix among themselves at the quantum level\nand the action's symmetries, such as parity and charge conjugation, allow an\nadditional Yukawa coupling. Consequently, for an appropriate fine-tuning of the\nYukawa terms, these mixings must be taken into account in the renormalization\nconditions. All Green's functions and renormalization factors are analytic\nexpressions depending on the number of colors, $N_c$, the number of flavors,\n$N_f$, and the gauge parameter, $\\alpha$, which are left unspecified. Knowledge\nof these renormalization factors is necessary in order to relate numerical\nresults, coming from nonperturbative studies, to the renormalized, ``physical\"\nGreen's functions of the theory.",
        "positive": "Non-perturbative Gauge-Higgs Unification: Symmetries and Order\n  Parameters: We consider pure SU(N) gauge theories defined on an orbifold lattice,\nanalogous to the S^1/Z_2 gauge theory orbifolds of the continuum, which\naccording to the perturbative analysis do not have a Higgs phase.\nNon-perturbatively the conclusion for N even is the opposite, namely that\nspontaneous symmetry breaking does take place and some of the gauge bosons\nbecome massive. We interpret this new, non-perturbative phenomenon both\nmathematically and physically."
    },
    {
        "anchor": "Observing instantons directly on the lattice without cooling: Based on the study of the simple Abelian Higgs model in $1+1$ dimensions we\nwill present a new method to identify and localize extended instantons. The\nidea is to measure the topological charge on regions somewhat larger than the\nextended instantons so as to average out the ultraviolet fluctuations but\nwithout losing the detailed topological information when going to the full\nspace. The instanton size and probability density can be directly extracted\nfrom this analysis. Local dislocations, which can be avoided for fine enough\nlattices, can be reinterpreted as modified boundary conditions producing\nsectors with net topological charge.",
        "positive": "Precise determination of the three-quark potential in SU(3) lattice\n  gauge theory: We investigate the static interquark potential for the three-quark system in\nSU(3) lattice gauge theory at zero temperature by using Monte Carlo\nsimulations. We extract the potential from the correlation function of the\nthree Polyakov loops, which are computed by employing the multilevel algorithm.\nWe obtain remarkably clean results of the three-quark potential for O(200) sets\nof the three-quark configurations of various sizes and geometries including not\nonly the cases that three quarks are put at the vertices of acute, right, and\nobtuse triangles, but also the extreme cases such that three quarks are put in\nline. We find several new interesting features of the three-quark potential and\nthen discuss its possible functional form."
    },
    {
        "anchor": "Digitizing lattice gauge theories in the magnetic basis: reducing the\n  breaking of the fundamental commutation relations: We present a digitization scheme for the lattice $\\mathrm{SU}(2)$ gauge\ntheory Hamiltonian in the $\\mathit{magnetic}$ $\\mathit{basis}$, where the gauge\nlinks are unitary and diagonal. The digitization is obtained from a particular\npartitioning of the $\\mathrm{SU}(2)$ group manifold, with the canonical momenta\nconstructed by an approximation of the Lie derivatives on this partitioning.\nThis construction, analogous to a discrete Fourier transform, preserves the\nspectrum of the kinetic part of the Hamiltonian and the canonical commutation\nrelations exactly on a subspace of the truncated Hilbert space, while the\nresidual subspace can be projected above the cutoff of the theory.",
        "positive": "Topological Charge in Two Flavors QCD with Optimal Domain-Wall Fermion: We measure the topological charge of the gauge configurations generated by\nlattice simulations of 2 flavors QCD on a $ 16^3 \\times 32 $ lattice, with\nOptimal Domain-Wall Fermion (ODWF) at $ N_s = 16 $ and plaquette gauge action\nat $ \\beta = 5.90 $. Using the Adaptive Thick-Restart Lanczos algorithm, we\nproject the low-lying modes of the 4D effective Dirac operator of ODWF, and\nobtain the topological charge and topological susceptibility. Our result of\ntopological susceptibility agrees with the sea-quark mass dependence predicted\nby the chiral perturbation theory, and provides a determination of the chiral\ncondensate."
    },
    {
        "anchor": "Kaon B-parameter using Overlap Fermions: I present first results from an in-progress calculation of B_K in quenched\napproximation using overlap fermions. My particular implementation of the\noverlap uses a kernel with nearest and next-nearest neighbor interactions and\nHYP-blocked gauge connections. Matching to the continuum NDR regularization is\ndone perturbatively. I present preliminary results at beta=5.9 and 6.1 (lattice\nspacings 0.125 and 0.09 fm) for quark masses, pseudoscalar decay constants, and\nB-parameter -- B_K(NDR(mu=2 GeV) is 0.66(3-4).",
        "positive": "A criterion for lattice supersymmetry: cyclic Leibniz rule: It is old folklore that the violation of Leibniz rule on a lattice is an\nobstruction for constructing a lattice supersymmetric model. While it is still\ntrue for full supersymmetry, we show that a slightly modified form of the\nLeibniz rule, which we call cyclic Leibniz rule (CLR), is actually a criterion\nfor the existence of partial lattice supersymmetry. In one dimension, we find\nsets of lattice difference operator and field multiplication smeared over\nlattice which satisfy the CLR under some natural assumptions such as\ntranslational invariance and locality. Thereby we construct a model of\nsupersymmetric lattice quantum mechanics without spoiling locality. The CLR\nrelation is coincident with the condition that the vanishing of the so-called\nsurface term in the construction by lattice Nicolai map. We can construct\nsuperfield formalism with arbitrary superpotential. This also enables us to\napply safely a localization technique to our model, because the kinetic term\nand the interaction terms of our model are independently invariant under the\nsupersymmetry transformation. A preliminary attempt in finding a solution for\nthe higher dimensional case is also discussed."
    },
    {
        "anchor": "On the generalised eigenvalue method and its relation to Prony and\n  generalised pencil of function methods: We discuss the relation of three methods to determine energy levels in\nlattice QCD simulations: the generalised eigenvalue, the Prony and the\ngeneralised pencil of function methods. All three can be understood as special\ncases of a generalised eigenvalue problem. We show analytically that the\nleading corrections to an energy $E_l$ in all three methods due to unresolved\nstates decay asymptotically exponentially like $\\exp(-(E_{n}-E_l)t)$. Using\nsynthetic data we show that these corrections behave as expected also in\npractice. We propose a novel combination of the generalised eigenvalue and the\nProny method, denoted as GEVM/PGEVM, which helps to increase the energy gap\n$E_{n}-E_l$. We illustrate its usage and performance using lattice QCD\nexamples.",
        "positive": "Thermodynamics of SU(3) Gauge Theory from Gradient Flow: A novel method to study the bulk thermodynamics in lattice gauge theory is\nproposed on the basis of the Yang-Mills gradient flow with a fictitious time t.\nThe energy density (epsilon) and the pressure (P) of SU(3) gauge theory at\nfixed temperature are calculated directly on 32^3 x (6,8,10) lattices from the\nthermal average of the well-defined energy-momentum tensor (T_{mu nu}^R(x))\nobtained by the gradient flow. It is demonstrated that the continuum limit can\nbe taken in a controlled manner from the t-dependence of the flowed data."
    },
    {
        "anchor": "One-loop matching of the $CP$-odd three-gluon operator to the gradient\n  flow: The calculation of the neutron electric dipole moment within effective field\ntheories for physics beyond the Standard Model requires non-perturbative\nhadronic matrix elements of effective operators composed of quark and gluon\nfields. In order to use input from lattice computations, these matrix elements\nmust be translated from a scheme suitable for lattice QCD to the\nminimal-subtraction scheme used in the effective-field-theory framework. The\naccuracy goal in the context of the neutron electric dipole moment necessitates\nat least a one-loop matching calculation. Here, we provide the one-loop\nmatching coefficients for the $CP$-odd three-gluon operator between two\ndifferent minimally subtracted 't Hooft-Veltman schemes and the gradient flow.\nThis completes our program to obtain the one-loop gradient-flow matching\ncoefficients for all $CP$-violating and flavor-conserving operators in the\nlow-energy effective field theory up to dimension six.",
        "positive": "Twist-3 partonic distributions from lattice QCD: Twist-3 partonic distributions contain important information that\ncharacterizes nucleon's structure. In this work, we show our lattice\nexploration of the twist-3 PDFs $g_T(x)$, and $h_L(x)$. We also present our\npreliminary results on the twist-3 GPD $\\tilde{G}_2(x)$. We use the\nquasi-distribution approach to connect the lattice-extracted matrix elements,\nrenormalized in the RI/MOM scheme, to light-cone distributions, applying the\nmatching procedure that we developed in parallel. We also calculate the twist-2\ncounterparts of $g_T(x)$ and $h_L(x)$, i.e. $g_1(x)$, and $h_1(x)$, and test\nthe Wandzura-Wilczek approximation."
    },
    {
        "anchor": "Charmed meson spectroscopy on the lattice: We present a calculation of the spectrum of low-lying D and D_s mesons\ncalculated on 2+1 flavor configurations with Clover-Wilson quarks generated by\nthe PACS-CS collaboration. S- and P-wave states are explored for pion masses\ndown to 156MeV, including some excited states. As a benchmark, a calculation of\nthe low-lying charmonium spectrum is performed. While the charmonium results\nagree favorably with experiment, noticeable differences remain for charmed\nmesons in channels where resonances close to multi-particle thresholds exist.",
        "positive": "Electromagnetic form factors of the nucleon from $N_f = 2 + 1$ lattice\n  QCD: There is a long-standing discrepancy between different measurements of the\nelectric and magnetic radii of the proton. Lattice QCD calculations are a\nwell-suited tool for theoretical investigations of the structure of the nucleon\nfrom first principles. However, all previous lattice studies of the proton's\nelectromagnetic radii have either neglected quark-disconnected contributions or\nwere not extrapolated to the continuum and infinite-volume limit. Here, we\npresent results for the electromagnetic form factors of the proton and neutron\ncomputed on the $(2 + 1)$-flavor Coordinated Lattice Simulations (CLS)\nensembles including both quark-connected and -disconnected contributions. From\nsimultaneous fits to the $Q^2$-, pion-mass, lattice-spacing, and finite-volume\ndependence of the form factors, we determine the electric and magnetic radii\nand the magnetic moments of the proton and neutron. For the proton, we obtain\nas our final values $\\langle r_E^2 \\rangle^p = (0.672 \\pm 0.014$ (stat)${} \\pm\n0.018$ (syst)$)$ fm${}^2$, $\\langle r_M^2 \\rangle^p = (0.658 \\pm 0.012$\n(stat)${} \\pm 0.008$ (syst)$)$ fm${}^2$, and $\\mu_M^p = 2.739 \\pm 0.063$\n(stat)${} \\pm 0.018$ (syst). The magnetic moment is in good agreement with the\nexperimental value, as is the one of the neutron. On the one hand, our result\nfor the electric (charge) radius of the proton clearly points towards a small\nvalue, as favored by muonic hydrogen spectroscopy and the recent\n$ep$-scattering experiment by PRad. Our estimate for the magnetic radius, on\nthe other hand, is well compatible with that inferred from the A1\n$ep$-scattering experiment."
    },
    {
        "anchor": "Gauge cooling for the singular-drift problem in the complex Langevin\n  method --a test in Random Matrix Theory for finite density QCD: Recently, the complex Langevin method has been applied successfully to finite\ndensity QCD either in the deconfinement phase or in the heavy dense limit with\nthe aid of a new technique called the gauge cooling. In the confinement phase\nwith light quarks, however, convergence to wrong limits occurs due to the\nsingularity in the drift term caused by small eigenvalues of the Dirac operator\nincluding the mass term. We propose that this singular-drift problem should\nalso be overcome by the gauge cooling with different criteria for choosing the\ncomplexified gauge transformation. The idea is tested in chiral Random Matrix\nTheory for finite density QCD, where exact results are reproduced at zero\ntemperature with light quarks. It is shown that the gauge cooling indeed\nchanges drastically the eigenvalue distribution of the Dirac operator measured\nduring the Langevin process. Despite its non-holomorphic nature, this\neigenvalue distribution has a universal diverging behavior at the origin in the\nchiral limit due to a generalized Banks-Casher relation as we confirm\nexplicitly.",
        "positive": "Loop inequalities and confinement: We consider correlation inequalities that follow from the well-known loop\nequations of LGT, and their analogues in spin systems. They provide a way of\nbounding long range by short or intermediate range correlations. In several\ncases the method easily reproduces results that otherwise require considerable\neffort to obtain. In particular, in the case of the 2-dimensional O(N) spin\nmodel, where large N analytical results are available, the absence of a phase\ntransition and the exponential decay of correlations for all $\\beta$ is easily\ndemonstrated. We report on the possible application of this technique to the\nanalogous 4-dimensional problem of area law for the Wilson loop in LGT at large\n$\\beta$."
    },
    {
        "anchor": "Fits of finite-volume smeared spectral densities: Motivated by recent progress in the numerical inversion of the Laplace\ntransform, we investigate applications of finite-volume smeared spectral\ndensities. These include the tuning of operator smearing, and the study of the\nfinite-volume spectrum.",
        "positive": "A Lattice Fermion Doublet With A Generalization Of The Ginsparg-Wilson\n  Relation: We present a new staggered discretization of the Dirac operator. In\ncomparison with standard staggered fermions, real and imaginary parts are\nlocated in different nodes. Doubling gives only a doublet of Dirac fermions\nwhich we propose to interpret as a physical (lepton or quark) doublet. Contrary\nto usual staggered fermions, we have no exact chiral symmetry but obtain a\ngeneralization of the Ginsparg-Wilson relation."
    },
    {
        "anchor": "Dirac b quark on the lattice: We perform the first study of treating b, c, and s quarks as Dirac fermions\nin lattice QCD with exact chiral symmetry. On a 32^3 60 lattice with 1/a ~ 7.68\nGeV, we compute point-to-point quark propagators, and measure the\ntime-correlation functions for mesons with quark contents b_bbar, c_bbar,\ns_bbar, and c_cbar. The lowest-lying meson mass spectra, the pseudoscalar decay\nconstants, and the b and c quark masses are determined.",
        "positive": "Dual Wilson Loop and Inter-Monopole Potential in Lattice QCD: We study the dual Wilson loop and the inter-monopole potential(the static\npotential between the color magnetic monopoles) in the maximally abelian gauge\nto clarify the dual Higgs mechanism induced by monopole condensation. There is\nno (color-)electric current in the monopole part, which includes the essence of\nthe nonperturbative QCD, and hence the system can be described by the dual\ngauge field $B_\\mu$ without the singularity like the Dirac string. We find that\nthe dual Wilson loop seems to obey the perimeter law, and the inter-monopole\npotential becomes Yukawa-type in the infrared region. From the inter-monopole\npotential, we estimate the dual gluon mass $m_B$ and the effective size $R$ of\nthe monopole: $m_B \\simeq 0.5$GeV, $R \\simeq 0.35$fm."
    },
    {
        "anchor": "Perturbative renormalization of the first moment of structure functions\n  for domain-wall QCD: Using the domain-wall formulation of lattice fermions, we have computed the\none-loop renormalization factors of one-link operators which measure the first\nnontrivial moment of the unpolarized, polarized and transversity structure\nfunctions, in the flavor nonsinglet sector. The knowledge of these factors is\nnecessary in order to extract physical numbers from domain-wall Monte Carlo\nsimulations of parton distributions.\n  We have automated the perturbative calculations by developing suitable FORM\ncodes. The results show that in many instances the total renormalization\nfactors are almost equal to one, and that hence the corresponding operators\nare, for the appropriate values of the Dirac mass $M$ and the coupling $g_0$,\npractically unrenormalized.",
        "positive": "Sign problem and MEM in lattice field theory with the $\u03b8$ term: Lattice field theory with the $\\theta$ term suffers from the sign problem.\nThe sign problem appears as flattening of the free energy.\n  As an alternative to the conventional method, the Fourier transform method\n  (FTM), we apply the maximum entropy method (MEM) to Monte Carlo data obtained\nusing the CP$^3$ model with the $\\theta$ term.\n  For data without flattening, we obtain the most probable images of the\npartition function ${\\hat{\\cal Z}}(\\theta)$ with rather small errors. The\nresults are quantitatively close to the result obtained with the\n  FTM. Motivated by this fact, we systematically investigate flattening in\nterms of the MEM.\n  Obtained images ${\\hat{\\cal Z}}(\\theta)$ are consistent with the FTM for\nsmall values of $\\theta$, while the behavior of ${\\hat{\\cal Z}}(\\theta)$\ndepends strongly on the default model for large values of $\\theta$.\n  This behavior of ${\\hat{\\cal Z}}(\\theta)$ reflects the flattening phenomenon."
    },
    {
        "anchor": "Studying the phase diagram of the three-flavor Schwinger model in the\n  presence of a chemical potential with measurement- and gate-based quantum\n  computing: We propose an ansatz quantum circuit for the variational quantum eigensolver\n(VQE), suitable for exploring the phase structure of the multi-flavor Schwinger\nmodel in the presence of a chemical potential. Our ansatz is capable of\nincorporating relevant model symmetries via constrains on the parameters, and\ncan be implemented on circuit-based as well as measurement-based quantum\ndevices. We show via classical simulation of the VQE that our ansatz is able to\ncapture the phase structure of the model, and can approximate the ground state\nto a high level of accuracy. Moreover, we perform proof-of-principle\nsimulations on superconducting, gate-based quantum hardware. Our results show\nthat our approach is suitable for current gate-based quantum devices, and can\nbe readily implemented on measurement-based quantum devices once available.",
        "positive": "Technicolor on the Lattice: Technicolor theories provide an elegant mechanism for dynamical electroweak\nsymmetry breaking. We will discuss the use of lattice simulations to study the\nstrongly-interacting dynamics of some of the candidate theories, with matter\nfields in representations other than the fundamental. To be viable candidates\nfor phenomenology, such theories need to be different from a scaled-up version\nof QCD, which were ruled out by LEP precision measurements, and represent a\nchallenge for modern lattice computations."
    },
    {
        "anchor": "Precision $B^*B\u03c0$ coupling from three-flavor lattice QCD: We consider three-flavor QCD and perform a determination of the low-energy\ncoupling $\\hat{g}_\\chi$ of SU(2) Heavy Meson Chiral Perturbation Theory. It is\nthe $B^*B\\pi$ coupling in the limit of static heavy and chiral light quarks and\nhas not been determined with precision thus far. The calculation is performed\non a large set of the $2+1$ flavor CLS ensembles with pion masses from 420 MeV\ndown to 130 MeV. This allows us to significantly reduce the systematic\nuncertainty from the chiral extrapolation compared to previous works. Only a\nweak dependence on the lattice spacing is visible in our results.",
        "positive": "Quarks and Triality in a Finite Volume: In order to understand the puzzle of the free energy of an individual quark\nin QCD, we explicitly construct ensembles with quark numbers $N_V\\neq 0\\!\\mod\n3$, corresponding to non-zero triality in a finite subvolume $V$ on the\nlattice. We first illustrate the basic idea in an effective Polyakov-loop\ntheory for the heavy-dense limit of QCD, and then extend the construction to\nfull Lattice QCD, where the electric center flux through the surface of $V$ has\nto be fixed at all times to account for Gauss's law. This requires introducing\ndiscrete Fourier transforms over closed center-vortex sheets around the spatial\nvolume $V$ between all subsequent time slices, and generalizes the construction\nof 't Hooft's electric fluxes in the purge gauge theory. We derive this same\nresult from a dualization of the Wilson fermion action, and from the transfer\nmatrix formulation with a local $\\mathbb Z_3$-Gauss law to restrict the\ndynamics to sectors with the required center charge in $V$."
    },
    {
        "anchor": "Reply to David's Comment on ``Superinstantons and the Reliability of\n  Perturbation Theory in Non-Abelian Models'': We reply to David's comment (hep-lat/9504017) on our paper Phys.Rev.Lett.\n74(1995)1920.",
        "positive": "Correlation Functions from Quantum Cluster Algorithms: Application to\n  U(1) Quantum Spin and Quantum Link Models: We demonstrate how correlation functions for non-diagonal operators can be\nmeasured with the loop-cluster algorithm for quantum spin models. We introduce\nthe U(1) quantum link model and present the construction of a cluster algorithm\nfor the model. We further show how an improved estimator for Wilson loops can\nbe realized with the flux-cluster algorithm."
    },
    {
        "anchor": "Light meson spectrum with $N_f=2$ dynamical overlap fermions: We present numerical simulation of QCD with two dynamical quark flavors\ndescribed by the overlap fermion action on a $16^3\\times 32\\times (0.12 {\\rm\nfm})^4$ lattice. We calculate pseudo-scalar masses and decay constants and\ninvestigate their chiral properties. We test the consistency of our data with\nthe two-loop chiral perturbation theory predictions, which should also be valid\nat finite lattice spacings because of the exact chiral symmetry, including the\nfinite size effects.",
        "positive": "Chiral perturbation theory for K+ to pi+ pi0 decay in the continuum and\n  on the lattice: In this paper we use one-loop chiral perturbation theory in order to compare\nlattice computations of the K+ to pi+ pi0 decay amplitude with the experimental\nvalue. This makes it possible to investigate three systematic effects that\nplague lattice computations: quenching, finite-volume effects, and the fact\nthat lattice computations have been done at unphysical values of the quark\nmasses and pion external momenta (only this latter effect shows up at tree\nlevel). We apply our results to the most recent lattice computation, and find\nthat all three effects are substantial. We conclude that one-loop corrections\nin chiral perturbation theory help in explaining the discrepancy between\nlattice results and the real-world value. We also revisit B_K, which is closely\nrelated to the K+ to pi+ pi0 decay amplitude by chiral symmetry."
    },
    {
        "anchor": "PLQCD library for Lattice QCD on multi-core machines: PLQCD is a stand-alone software library developed under PRACE for lattice\nQCD. It provides an implementation of the Dirac operator for Wilson type\nfermions and few efficient linear solvers. The library is optimized for\nmulti-core machines using a hybrid parallelization with OpenMP+MPI. The main\nobjectives of the library is to provide a scalable implementation of the Dirac\noperator for efficient computation of the quark propagator. In this\ncontribution, a description of the PLQCD library is given together with some\nbenchmark results.",
        "positive": "Derivative sources in lattice spectroscopy of excited light-quark mesons: We construct efficient interpolating fields for lattice spectroscopy of\nmesons by applying covariant derivatives on Jacobi smeared quark sources. These\ninterpolators are tested in a quenched calculation of excited mesons based on\nthe variational method. We present results for pseudoscalar, scalar, vector and\npseudovector mesons."
    },
    {
        "anchor": "Testing logarithmic violations to scaling in strongly coupled QED: Using very precise measurements of the critical couplings for the chiral\ntransition of non compact $QED_4$ with up to 8 flavours, we analyse the\nbehaviour of the order parameter at the critical point using the equation of\nstate of a logarithmically improved scalar mean field theory, that of the\nNambu-Jona Lasinio theory and a pure power law. The first case is definitively\nexcluded by the numerical data. The stability of the fits for the last two\ncases, as well as the behaviour with the number of flavours of the exponent of\nthe logarithmic violations to the scaling favour clearly a pure power law\nscaling with non mean field exponents.",
        "positive": "A Possible Origin of the Wilson Lattice Fermion: Considering relevant and irrelevant high-dimension operators for ordinary and\nmirror fermions respectively, we show that the Wilson lattice fermion can\noriginate from a spontaneous symmetry breaking phenomenon. Ward identities, due\nto symmetries at the cutoff, guarantee the cancellation of mirror-fermion\ncontributions and the infrared limit can be achieved. The Wilson parameter\nturns out to be fixed at $r\\simeq 0.18$, where the vacuum energy of the system\nis minimized."
    },
    {
        "anchor": "Finite size effect on pseudoscalar meson sector in 2+1 flavor QCD at the\n  physical point: We investigate the finite size effect on pseudoscalar meson masses and decay\nconstants using a subset of the \"PACS10\" configurations which are generated\nkeeping the space-time volumes over (10 fm$)^4$ in 2+1 flavor QCD at the\nphysical point. We have tried two kinds of analyses, fixing $\\kappa$ values or\nmeasured axial Ward identity quark masses. Comparing the results on (5.4\nfm$)^4$ and (10.8 fm$)^4$ lattices, we have found a sizable finite size effect\non the pseudoscalar meson sector in the former analysis: a 2.1(8)%, 4.8(1.6)%,\nand 0.36(31)% finite size effect on $m_\\pi$, $m_{\\rm ud}$, and $f_\\pi$,\nrespectively, on the (5.4 fm$)^4$ lattice. For the latter analysis, the finite\nsize effect on the pseudoscalar meson decay constants is 0.66(33)% for $f_\\pi$,\n0.26(13)% for $f_K$, and 0.40(32)% for $f_K/f_\\pi$. These values with two-sigma\nerror bars are consistent with the predictions from the full one-loop SU(3)\nchiral perturbation theory, which are 0.20% for $f_\\pi$, 0.08% for $f_K$, and\n0.13% for $f_K/f_\\pi$. The finite size effect on the pseudoscalar meson masses\nis hardly detected under the current statistical precision.",
        "positive": "SUSY WT identity in a lattice formulation of 2D $\\mathcal{N}=(2,2)$ SYM: We address some issues relating to a supersymmetric (SUSY) Ward-Takahashi\n(WT) identity in Sugino's lattice formulation of two-dimensional (2D)\n$\\mathcal{N}=(2,2)$ $SU(k)$ supersymmetric Yang-Mills theory (SYM). A\nperturbative argument shows that the SUSY WT identity in the continuum theory\nis reproduced in the continuum limit without any operator\nrenormalization/mixing and tuning of lattice parameters. As application of the\nlattice SUSY WT identity, we show that a prescription for the hamiltonian\ndensity in this lattice formulation, proposed by Kanamori, Sugino and Suzuki,\nis justified also from a perspective of an operator algebra among\ncorrectly-normalized supercurrents. We explicitly confirm the SUSY WT identity\nin the continuum limit to the first nontrivial order in a semi-perturbative\nexpansion."
    },
    {
        "anchor": "Dual Computations of Non-abelian Yang-Mills on the Lattice: In the past several decades there have been a number of proposals for\ncomputing with dual forms of non-abelian Yang-Mills theories on the lattice.\nMotivated by the gauge-invariant, geometric picture offered by dual models and\nsuccessful applications of duality in the U(1) case, we revisit the question of\nwhether it is practical to perform numerical computation using non-abelian dual\nmodels. Specifically, we consider three-dimensional SU(2) pure Yang-Mills as an\naccessible yet non-trivial case in which the gauge group is non-abelian. Using\nmethods developed recently in the context of spin foam quantum gravity, we\nderive an algorithm for efficiently computing the dual amplitude and describe\nMetropolis moves for sampling the dual ensemble. We relate our algorithms to\nprior work in non-abelian dual computations of Hari Dass and his collaborators,\naddressing several problems that have been left open. We report results of spin\nexpectation value computations over a range of lattice sizes and couplings that\nare in agreement with our conventional lattice computations. We conclude with\nan outlook on further development of dual methods and their application to\nproblems of current interest.",
        "positive": "Quarkonium correlation functions at finite temperature in the charm to\n  bottom region: Quarkonium correlation functions at finite temperature were studied in a\nregion of the quark mass for charmonia to bottomonia in quenched lattice QCD\nwith $O(a)$-improved Wilson quarks. Our simulations were performed on large\nisotropic lattices at temperatures in the range from about 0.80$T_c$ to\n1.61$T_c$. We investigated quarkonium behavior in terms of temperature\ndependence as well as quark mass dependence of the quarkonium correlation\nfunctions and related quantities at both vanishing and finite momenta."
    },
    {
        "anchor": "Scaling properties of Wilson loops pierced by P-vortices: P-vortices, in an SU(N) lattice gauge theory, are excitations on the\ncenter-projected Z(N) lattice. We study the ratio of expectation values of\nSU(2) Wilson loops, on the unprojected lattice, linked to a single P-vortex, to\nthat of Wilson loops which are not linked to any P-vortices. When these ratios\nare plotted versus loop area in physical units, for a range of lattice\ncouplings, it is found that the points fall approximately on a single curve,\nconsistent with scaling. We also find that the ratios are rather insensitive to\nthe point where the minimal area of the loop is pierced by the P-vortex.",
        "positive": "Lattice Chiral Symmetry in Fermionic Interacting Theories and the\n  Antifield Formalism: Recently we have discussed realization of an exact chiral symmetry in\ntheories with self-interacting fermions on the lattice, based upon an auxiliary\nfield method. In this paper we describe construction of the lattice chiral\nsymmetry and discuss its structure in more detail. The antifield formalism is\nused to make symmetry consideration more transparent. We show that the quantum\nmaster equation in the antifield formalism generates all the relevant\nWard-Takahashi identities including a Ginsparg-Wilson relation for interacting\ntheories. Solutions of the quantum master equation are obtained in a closed\nform, but the resulting actions are found to be singular. Canonical\ntransformations are used to obtain four types of regular actions. Two of them\nmay define consistent quantum theories. Their Yukawa couplings are the same as\nthose obtained by using the chiral decomposition in the free field algebra.\nInclusion of the complete set of the auxiliary fields is briefly discussed."
    },
    {
        "anchor": "Charm fluctuations in (2+1)-flavor QCD at high temperature: Using the high statistics datasets of the HotQCD Collaboration, generated\nwith the HISQ (2+1)-flavor action for light and strange quarks, and treating\nthe charm sector in the quenched approximation, we analyze the second and\nfourth order cumulants of charm fluctuations and the correlations of charm with\nlighter conserved flavor quantum numbers. We can make use of a factor 100\nlarger statistics on ${N_\\tau =8}$ lattices which never have been used in\nstudies of charm fluctuations. Analyzing correlations of charm fluctuations\nwith baryon number and electric charge fluctuations we can project onto charmed\nbaryon and meson correlations and compare results with quark model extended\nhadron resonance gas model calculations. We aim at a precise determination of\nthe dissociation temperature of charmed hadrons and will probe the sensitivity\nof the fluctuations observables to the presence of multiple-charmed baryons.",
        "positive": "Reflection Positivity of N=1 Wess-Zumino model on the lattice with exact\n  U(1)_R symmetry: By using overlap Majorana fermions, the ${\\cal N}=1$ chiral multiple can be\nformulated so that the supersymmetry is manifest and the vacuum energy is\ncancelled in the free limit, thanks to the bilinear nature of the free action.\nIt is pointed out, however, that in this formulation the reflection positivity\nis violated in the bosonic part of the action, although it is satisfied in the\nfermionic part. It is found that the positivity of the spectral density of the\nbosonic two-point correlation function is ensured only for the spacial momenta\n$a | p_k | \\lesssim 1.72$ $(k=1,2,3)$. It is then argued that in formulating\n${\\cal N}=1$ Wess-Zumino model with the overlap Majorana fermion, one may adopt\na simpler nearest-neighbor bosonic action, discarding the free limit manifest\nsupersymmetry. The model still preserves the would-be U(1)$_R$ symmetry and\nsatisfies the reflection positivity."
    },
    {
        "anchor": "Monte Carlo studies on the expanding behavior of the early universe in\n  the Lorentzian type IIB matrix model: The type IIB matrix model is a conjectured nonperturbative formulation of\nsuperstring theory. Recently the Lorentzian version of the model has been\nstudied by Monte Carlo simulation, and it has been shown that only three out of\nnine spatial directions start to expand after a critical time. We extend this\nwork by investigating the expanding behavior for much longer time. We find that\nthe 3d space expands exponentially for some period of time, which may be\ninterpreted as inflation. We also simulate a simplified model, which is\nexpected to capture some qualitative features of the original model at much\nlater times. We observe that the exponential expansion eventually changes into\na power-law t^(1/2) behavior, which agrees with the expanding behavior of the\nFriedmann-Robertson-Walker (FRW) universe in the radiation dominated era.",
        "positive": "Chiral symmetry breaking in lattice brane QED model: We propose a novel lattice calculation of spontaneous chiral symmetry\nbreaking in QED model with 2+1 dimensional fermion brane. Considering the\nrelativistic action with gauge symmetry we rigorously carry out path integral\nin Monte-Carlo simulation with Fermi-velocity relevant to effective coupling\nconstant. We numerically show the evidence of spontaneous chiral symmetry\nbreaking in strong coupling region with chiral condensate, low-lying mode\ndistribution and Nambu-Goldstone boson spectrum in bare Fermi-velocty $v=0.1$.\nThis is a feasible study to investigate the phase structure of Graphene."
    },
    {
        "anchor": "Polyakov Loops and Finite-Size Effects of Hadron Masses in Lattice Full\n  Q.C.D: The polarization of Polyakov type loops is responsible for the difference\nbetween quenched and unquenched finite size effects on the QCD mass spectrum.\nWith a numerical simulation, using different sea quarks boundary conditions, we\nshow that we can align the spatial Polyakov loops in a predefined direction.\nStarting from these results, we propose a procedure to partially remove the\nPolyakov type contributions in the meson propagators.",
        "positive": "Gauge invariant extremization: Recently, Duncan and Mawhinney introduced a method to find saddle points of\nthe action in simulations of non-abelian lattice gauge theory. The idea, called\n`extremization', is to minimize $\\int(\\delta S/\\delta A_\\mu)^2$ instead of the\naction $S$ itself as in conventional `cooling'. The method was implemented in\nan explicitly gauge variant way, however, and gauge dependence showed up in the\nresults. Here we present a gauge invariant formulaton of extremization on the\nlattice, applicable to any gauge group and any lattice action. The procedure is\nworked out in detail for U(1) and SU(N) lattice gauge theory with the plaquette\naction."
    },
    {
        "anchor": "String tensions of SU(N) gauge theories in 2+1 dimensions: We calculate the energy spectrum of closed strings in SU(N) gauge theories\nwith N=2,3,4,6,8 in 2+1 dimensions to a high accuracy. We attempt to control\nall systematic errors, and this allows us to perform a precise comparison with\ndifferent theoretical predictions.\n  When we study the dependence of the string mass on its length L we find that\nthe Nambu-Goto prediction is a very good approximation down to relatively short\nlengths, where the Luscher term alone is insufficient. We then isolate the\ncorrections to the Luscher term, and compare them to recent theoretical\npredictions, which indeed seem to be mildly preferred by the data.\n  When we take these corrections into account and extract string tensions from\nthe string masses, we find that their continuum limit is lower by 2%-1% from\nthe predictions of Karabli, Kim, and Nair. The discrepancy decreases with N,\nbut when we extrapolate our results to N=oo we still find a discrepancy of\n0.88% which is a 4.5 sigma effect.",
        "positive": "Moebius Fermions: We introduce a new domain wall operator that represents a full (real) Moebius\ntransformation of a given non-chiral Dirac kernel. Shamir's and Borici's domain\nwall fermions are special cases of this new class. By tuning the parameters of\nthe Moebius operator and by introducing a new Red/Black preconditioning, we are\nable to reduce the computational effort substantially."
    },
    {
        "anchor": "Lattice QCD approach to nuclear force: We present our updated results of the nucleon-nucleon potential in quenched\nlattice QCD simulations with the plaquette gauge action and the Wilson quark\naction on the 32^4(\\simeq (4.4 fm)^4) lattice. From the equal-time\nBethe-Salpeter (BS) wave function, the NN potential is constructed through the\nSchroedinger-type equation. Resulting NN potential has all the qualitative\nfeatures which phenomenological potentials commonly have: the repulsive core at\nshort distance and the attractive well at medium and long distances. In the L\n\\to \\infty limit, our NN potential is guaranteed to reproduce the scattering\nlength obtained from the Luescher's formula. The quark mass dependence of the\nNN potential is studied with m_{pi} \\sim 380, 529, 731 MeV. The results suggest\nthat both the repulsive core at short distance and the attractive well at\nmedium distance are enhanced in the light quark mass region.",
        "positive": "Crystalline phases at finite winding densities in a quantum link ladder: Condensed matter physics of gauge theories coupled to fermions can exhibit a\nrich phase structure, but are nevertheless very difficult to study in Monte\nCarlo simulations when they are afflicted by a sign problem. As an alternate\napproach, we use tensor network methods to explore the finite density physics\nof Abelian gauge theories without dynamical matter. As a concrete example, we\nconsider the U(1) gauge invariant quantum link ladder with spin-1/2 gauge\nfields in an external electric field which cause the winding electric fluxes to\ncondense in the ground state. We demonstrate how the electric flux tubes\narrange themselves in the bulk giving rise to crystalline patterns, whose\nperiod can be controlled by tuning the external field. We propose observables\nto detect the transitions in ground state properties not only in numerical\nexperiments, but also in future cold-atom realizations. A systematic procedure\nfor reaching the thermodynamic limit, as well as extending the studies from\nladders to extended geometries is outlined."
    },
    {
        "anchor": "Large Loops of Magnetic Current and Confinement in Four Dimensional\n  $U(1)$ Lattice Gauge Theory: We calculate the heavy quark potential from the magnetic current due to\nmonopoles in four dimensional $U(1)$ lattice gauge theory. The magnetic current\nis found from link angle configurations using the DeGrand-Toussaint\nidentification method. The link angle configurations are generated in a cosine\naction simulation on a $24^4$ lattice. The magnetic current is resolved into\nlarge loops which wrap around the lattice and simple loops which do not.\nWrapping loops are found only in the confined phase. It is shown that the long\nrange part of the heavy quark potential, in particular the string tension, can\nbe calculated solely from the large, wrapping loops of magnetic current.",
        "positive": "Kondo effect with Wilson fermions: We investigate the Kondo effect with Wilson fermions. This is based on a\nmean-field approach for the chiral Gross-Neveu model including four-point\ninteractions between a light Wilson fermion and a heavy fermion. For massless\nWilson fermions, we demonstrate the appearance of the Kondo effect. We point\nout that there is a coexistence phase with both the light-fermion scalar\ncondensate and Kondo condensate, and the critical chemical potentials of the\nscalar condensate are shifted by the Kondo effect. For negative-mass Wilson\nfermions, we find that the Kondo effect is favored near the parameter region\nrealizing the Aoki phase. Our findings will be useful for understanding the\nroles of heavy impurities in Dirac semimetals, topological insulators, and\nlattice simulations."
    },
    {
        "anchor": "Masses of singlet and non-singlet 0++ particles: We compute the mass of the singlet 0++ state using both (psi_bar psi) and\nWilson loop operators from a N_f=2 lattice QCD calculation.",
        "positive": "Monopoles and the 't Hooft tensor for generic gauge group: We study monopoles and corresponding 't Hooft tensor in a generic gauge\ntheory. This issue is relevant to the understanding of color confinement."
    },
    {
        "anchor": "Charmonium and exotics from lattice QCD: We review selected lattice results on the charmonium spectrum and first\nattempts to search for the existence of exotic states. The hadro-quarkonium\nmodel was proposed to interpret some of the exotic states as a quarkonium core\ninside a hadron. We present a lattice study of the hadro-quarkonium model in\nthe limit of static quarks. The charm quark decouples in low energy observables\nand binding energies of charmonium. In a model calculation we are able to\nevaluate the corrections to decoupling of the charm quark in the continuum.",
        "positive": "Abelian gauge theories on the lattice: $\u03b8$-terms and compact gauge\n  theory with(out) monopoles: We discuss a particular lattice discretization of abelian gauge theories in\narbitrary dimensions. The construction is based on gauging the center symmetry\nof a non-compact abelian gauge theory, which results in a Villain type action.\nWe show that this construction has several benefits over the conventional\n$U(1)$ lattice gauge theory construction, such as electric-magnetic duality,\nnatural coupling of the theory to magnetically charged matter in four\ndimensions, complete control over the monopoles and their charges in three\ndimensions and a natural $\\theta$-term in two dimensions. Moreover we show that\nfor bosonic matter our formulation can be mapped to a worldline/worldsheet\nrepresentation where the complex action problem is solved. We illustrate our\nconstruction by explicit dualizations of the $CP(N\\!-\\!1)$ and the gauge Higgs\nmodel in $2d$ with a $\\theta$ term, as well as the gauge Higgs model in $3d$\nwith constrained monopole charges. These models are of importance in low\ndimensional anti-ferromagnets. Further we perform a natural construction of the\n$\\theta$-term in four dimensional gauge theories, and demonstrate the Witten\neffect which endows magnetic matter with a fractional electric charge. We\nextend this discussion to $PSU(N)=SU(N)/\\mathbb Z_N$ non-abelian gauge theories\nand the construction of discrete $\\theta$-terms on a cubic lattice."
    },
    {
        "anchor": "An asymptotic formula for the pion decay constant in a large volume: We derive an asymptotic formula a la Luscher for the finite volume correction\nto the pion decay constant: this is expressed as an integral over the < 3 \\pi |\nA_\\mu|0 > amplitude after proper subtraction of the pion pole contribution. We\nanalyze the formula numerically at leading and next-to-leading order in the\nchiral expansion.",
        "positive": "Operators for scattering of particles with spin: Operators for simulating the scattering of two particles with spin are\nconstructed. Three methods are shown to give the consistent lattice operators\nfor PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar meson,\nvector meson and nucleon. The projection method leads to one or several\noperators $O_{\\Gamma,r,n}$ that transform according to a given irreducible\nrepresentation $\\Gamma$ and row r. However, it gives little guidance on which\ncontinuum quantum numbers of total J, spin S, orbital momentum L or\nsingle-particle helicities $\\lambda_{1,2}$ will be related with a given\noperator. This is remedied with the helicity and partial-wave methods. There\nfirst the operators with good continuum quantum numbers $(J,P,\\lambda_{1,2})$\nor $(J,L,S)$ are constructed and then subduced to the irreps $\\Gamma$ of the\ndiscrete lattice group. The results indicate which linear combinations\n$O_{\\Gamma,r,n}$ of various n have to be employed in the simulations in order\nto enhance couplings to the states with desired continuum quantum numbers. The\ntotal momentum of two hadrons is restricted to zero since parity P is a good\nquantum number in this case."
    },
    {
        "anchor": "Numerical studies on the finite-temperature CP restoration in 4D SU(N)\n  gauge theory at $\u03b8=\u03c0$: Recent studies on the 't Hooft anomaly matching condition have suggested a\nnontrivial phase structure in 4D SU($N$) gauge theory at $\\theta=\\pi$. In the\nlarge-$N$ limit, it has been found that CP symmetry at $\\theta=\\pi$ is broken\nin the confined phase, while it restores in the deconfined phase, which is\nindeed one of the possible scenarios. However, at small $N$, one may find other\nsituations that are consistent with the consequence of the anomaly matching\ncondition. Here we investigate this issue for $N=2$ by direct lattice\ncalculations. The crucial point to note is that the CP restoration can be\nprobed by the sudden change of the tail of the topological charge distribution\nat $\\theta=0$, which can be seen by simulating the theory at imaginary $\\theta$\nwithout the sign problem. Our results suggest that the CP restoration at\n$\\theta=\\pi$ occurs at temperature higher than the deconfining temperature\nunlike the situation in the large-$N$ limit.",
        "positive": "Code Optimization on Kepler GPUs and Xeon Phi: Kepler GTX Titan Black and Kepler Tesla K40 are still the best GPUs for high\nperformance computing, although Maxwell GPUs such as GTX 980 are available in\nthe market. Hence, we measure the performance of our lattice QCD codes using\nthe Kepler GPUs. We also upgrade our code to use the latest CPS (Columbia\nPhysics System) library along with the most recent QUDA (QCD CUDA) library for\nlattice QCD. These new libraries improve the performance of our conjugate\ngradient (CG) inverter so that it runs twice faster than before. We also\ninvestigate the performance of Xeon Phi 7120P coprocessor. It has similar\ncomputing power with the Kepler GPUs in principle. However, its performance for\nour CG code is significantly inferior to that of the GTX Titan Black GPUs at\npresent."
    },
    {
        "anchor": "A fresh look at the confinement mechanism: Topological configurations, monopoles and vortices, successfully describe\nquark confinement and the spontaneous breakdown of chiral symmetry. Despite\ntheir infinite action, these configurations are relevant due to a subtle\ncancellation between action and entropy. A natural explanation for this\nintrinsic fine-tuning is that smooth low action configurations exist which\nconfine and which appear as singular topological objects in certain gauges. To\nreveal these confining semi-classical configurations, a new cooling method is\nproposed which largely reduces the action while preserving the asymptotic\nquark-antiquark potential. First numerical results for a SU(2) gauge theory\nshow that confining configurations with an average plaquette as high as 0.95 do\nexist.",
        "positive": "Monte Carlo simulations on the Lefschetz thimble: taming the sign\n  problem: We present the first practical Monte Carlo calculations of the recently\nproposed Lefschetz thimble formulation of quantum field theories. Our results\nprovide strong evidence that the numerical sign problem that afflicts Monte\nCarlo calculations of models with complex actions can be softened significantly\nby changing the domain of integration to the Lefschetz thimble or\napproximations thereof. We study the interacting complex scalar field theory\n(relativistic Bose gas) in lattices of size up to 8^4 using a computationally\ninexpensive approximation of the Lefschetz thimble. Our results are in\nexcellent agreement with known results. We show that - at least in the case of\nthe relativistic Bose gas - the thimble can be systematically approached and\nthe remaining residual phase leads to a much more tractable sign problem (if at\nall) than the original formulation. This is especially encouraging in view of\nthe wide applicability - in principle - of our method to quantum field theories\nwith a sign problem. We believe that this opens up new possibilities for\naccurate Monte Carlo calculations in strongly interacting systems of sizes much\nlarger that previously possible."
    },
    {
        "anchor": "Radial and orbital excitation energies of charmonium: The charmonium system has several excited states below the energy threshold\nfor decay into $D$ and $\\bar{D}$ mesons, which can in principle be studied\naccurately in lattice QCD. Studies that include many states in the spectrum\nhave typically only been done at one value of the lattice spacing and with\nrelatively heavy light quarks in the sea. Here we give preliminary results for\nradial and orbital excitation energies for charmonium from a calculation on\n2+1+1 MILC configurations at multiple lattice spacings and including physical\nvalues for $u/d$ quark masses. We use the HISQ formulation for $c$ to obtain\nsmall discretisation errors and smeared operators to improve excited state\noverlap.",
        "positive": "Scaling Analysis of Improved Actions for Pure SU(3) Gauge Theory: We have explored the behaviour of some improved actions based on a\nnonperturbative renormalization group (RG) analysis in coupling space. We\ncalculate the RG flow in two-coupling space $(\\boneone,\\bonetwo)$ and examine\nthe restoration of rotational invariance and the scaling of physical quantities\n$(T_c/\\sqrt{\\sigma})$."
    },
    {
        "anchor": "The Anderson transition in QCD with $N_f=2+1+1$ twisted mass quarks:\n  overlap analysis: Chiral Random Matrix Theory has proven to describe the spectral properties of\nlow temperature QCD very well. However, at temperatures above the chiral\nsymmetry restoring transition it can not provide a global description. The\nlevel-spacing distribution in the lower part of the spectrum of the Dirac\noperator is Poisson-like. There the eigenmodes are localized in space-time and\nseparated from the rest of the spectrum by a so-called mobility edge. In\nanalogy to Anderson localization in condensed-matter systems with random\ndisorder this has been called the QCD-Anderson transition. Here, we study the\nlocalization features of the low-lying eigenmodes of the massless overlap\noperator on configurations generated with $N_f=2+1+1$ twisted mass Wilson sea\nquarks and present results concerning the temperature dependence of the\nmobility edge and the mechanism of the quark-mode localization. We have used\nvarious methods to fix the spectral position of the delocalization transition\nand verify that the mobility edge extrapolates to zero at a temperature within\nthe chiral transition region.",
        "positive": "Critical point search from an extended parameter space of lattice QCD at\n  finite temperature and density: Aiming to understand the phase structure of lattice QCD at nonzero\ntemperature and density, we study the phase transitions of QCD in an extended\nparameter space, where the number of flavor and quark masses are considered as\nparameters. Performing simulations of 2 flavor QCD and using the reweighting\nmethod, we investigate (2+Nf) flavor QCD at finite density, where two light\nflavors and Nf massive flavors exist. Calculating probability distribution\nfunctions, we determine the critical surface terminating first order phase\ntransitions in the parameter space of the light quark mass, the heavy quark\nmass and the chemical potential. Through the study of the many flavor system,\nwe discuss the phase structure of QCD at finite density."
    },
    {
        "anchor": "Simulation of the Lattice QCD and Technological Trends in Computation: Simulation of Lattice QCD is a challenging computational problem. Currently,\ntechnological trends in computation show multiple divergent models of\ncomputation. We are witnessing homogeneous multi-core architectures, the use of\naccelerator on-chip or off-chip, in addition to the traditional architectural\nmodels.\n  On the verge of this technological abundance, assessing the performance\ntrade-offs of computing nodes based on these technologies is of crucial\nimportance to many scientific computing applications.\n  In this study, we focus on assessing the efficiency and the performance\nexpected for the Lattice QCD problem on representative architectures and we\nproject the expected improvement on these architectures and their impact on\nperformance for Lattice QCD. We additionally try to pinpoint the limiting\nfactors for performance on these architectures.",
        "positive": "Eguchi-Kawai model with dynamical adjoint fermions: It is believed that fermions in adjoint representation on single site lattice\nwill restore the center symmetry, which is a crucial requirement for the volume\nindependence of large-N lattice gauge theories. We present a perturbative\nanalysis which supports the assumption for overlap fermions, but shows that\ncenter symmetry is broken for naive fermions."
    },
    {
        "anchor": "$\u03c0N \u03c3$ Term and Quark Spin Content of the Nucleon: We report results of our calculation on the $\\pi N\\sigma$ term and quark spin\ncontent of the nucleon on the quenched $16^3 \\times 24$ lattice at $\\beta =\n6.0$. The disconnected insertions which involve contributions from the sea\nquarks are calculated with the stochastic $Z_2$ noise algorithm. As a physical\ntest of the algorithm, we show that the forward matrix elements of the vector\nand pseudoscalar currents for the disconnected insertions are indeed consistent\nwith the known results of zero. We tried the Wuppertal smeared source and found\nit to be more noisy than the point source. With unrenormalized\n$m_q=4.42(17)$MeV, we find the $\\pi N\\sigma$ term to be $39.2\\pm 5.2$ MeV. The\nstrange quark condensate in the nucleon is large, i.e. $\\langle\nN|\\bar{s}s|N\\rangle = 1.16 \\pm 0.54$. For the quark spin content, we find\n$\\Delta u =0.78\\pm 0.07$, $\\Delta d =-0.42\\pm 0.07$, and $\\Delta s = -0.13\\pm\n0.06$. The flavor-singlet axial charge $g_A^1 = \\Delta \\Sigma =0.22\\pm 0.09 $.",
        "positive": "Finite size scaling analysis of intermittency moments in the two\n  dimensional Ising model: Finite size scaling is shown to work very well for the block variables used\nin intermittency studies on a 2-d Ising lattice. The intermittency exponents so\nderived exhibit the expected relations to the magnetic critical exponent of the\nmodel. Email contact: pesch@amoco.saclay.cea.fr"
    },
    {
        "anchor": "Opposite-Parity Contaminations in Lattice Nucleon Form Factors: The recently-introduced Parity Expanded Variational Analysis (PEVA) technique\nallows for the isolation of baryon eigenstates at finite momentum free from\nopposite-parity contamination. In this paper, we establish the formalism for\ncomputing form factors of spin-1/2 states using PEVA. Selecting the vector\ncurrent, we compare the electromagnetic form factors of the ground state\nnucleon extracted via this technique to a conventional parity-projection\napproach. Our results show a statistically significant discrepancy between the\nPEVA and conventional analyses. This indicates that existing calculations of\nmatrix elements of ground state baryons at finite momentum can be affected by\nsystematic errors of ~20% at physical quark masses. The formalism introduced\nhere provides an effective approach to removing these systematic errors.",
        "positive": "Abelian monopoles in finite temperature lattice SU(2) gluodynamics:\n  first study with improved action: The properties of the thermal Abelian color-magnetic monopoles in the\nmaximally Abelian gauge are studied in the deconfinement phase of the lattice\nSU(2) gluodynamics. To check universality of the monopole properties we employ\nthe tadpole improved Symanzik action. The simulated annealing algorithm\ncombined with multiple gauge copies is applied for fixing the maximally Abelian\ngauge to avoid effects of Gribov copies. We compute the density, interaction\nparameters, thermal mass and chemical potential of the thermal Abelian\nmonopoles in the temperature range between Tc and 3Tc. In comparison with\nearlier findings our results for these quantities are improved either with\nrespect to effects of Gribov copies or with respect to lattice artifacts."
    },
    {
        "anchor": "Chiral extrapolation of matrix elements of BSM kaon operators: Models of new physics induce K_0-K_0bar mixing through operators having Dirac\nstructures other than the \"left-left\" form of the Standard Model. To carry out\nthe chiral-continuum extrapolation of results from numerical simulations, one\nneeds to know the quark mass and lattice spacing dependence of the\ncorresponding B-parameters in the partially quenched theory at least at\nnext-to-leading order. For simulations using staggered fermions (such as that\nwe are doing with HYP-smeared valence fermions on the MILC asqtad lattices) one\nmust determine this dependence using staggered chiral perturbation theory\n(SChPT). We have calculated the required dependence in both SU(3) and SU(2)\nSChPT, working at next-to-leading order, and we give here an overview of the\nmethodology and results. The SU(3) SChPT result turns out to be much simpler\nthan that for the Standard Model B_K operator, due to the absence of chiral\nsuppression for the new operators. The SU(2) SChPT result turns out to be\nclosely related to that for B_K: the chiral logarithms are identical, up to an\noperator-dependent sign. Our results are also useful for fermions with chiral\nsymmetry as they provide, in the continuum limit, the partially quenched\ngeneralization of existing continuum results.",
        "positive": "Strategies for an accurate determination of the X(3872) energy from QCD\n  lattice simulations: We develop a method to determine accurately the binding energy of the X(3872)\nfrom lattice data for the $D \\bar D^*$ interaction. We show that, because of\nthe small difference between the neutral and charged components of the X(3872),\nit is necessary to differentiate them in the energy levels of the lattice\nspectrum if one wishes to have a precise determination of the the binding\nenergy of the X(3872). The analysis of the data requires the use of coupled\nchannels. Depending on the number of levels available and the size of the box\nwe determine the precision needed in the lattice energies to finally obtain a\ndesired accuracy in the binding energy."
    },
    {
        "anchor": "The repulsive core of the NN potential and the operator product\n  expansion: We investigate the short distance behavior of the nucleon--nucleon (NN)\npotential defined through the Bethe-Salpeter wave function, by perturbatively\ncalculating anomalous dimensions of 6--quark operators in QCD. Thanks to the\nasymptotic freedom of QCD, the 1-loop estimations give exact results for the\npotential in the zero distance limit. We show that the chiral symmetry of the\ngauge interaction implies the existence of an operator whose anomalous\ndimension is zero for a given quantum number. Furthermore we find that non-zero\nanomalous dimensions of other operators are all negative. These results predict\nthe functional form of the NN potential at short distance, which is a little\nweaker than $r^{-2}$. On the other hand, the computation of the anomalous\ndimension spectrum alone can not determine whether the potential is repulsive\nor attractive at short distance. An additional analytic non-perturbative\nanalysis suggests that the force at short distance is indeed repulsive at low\nenergy as found numerically. Some extensions of the method are briefly\ndiscussed.",
        "positive": "Fluctuations Destroying Long-Range Order in SU(2) Yang-Mills Theory: We study lattice SU(2) Yang-Mills theory with dimension $d\\ge 4$. The model\ncan be expressed as a $(d-1)$-dimensional O(4) non-linear $\\sigma$-model in a\n$d$-dimensional heat bath. As is well known, the non-linear $\\sigma$-model\nalone shows a phase transition. If the quark confinement is a consequence of\nabsence of a phase transition for the Yang-Mills theory, then the fluctuations\nof the heat bath must destroy the long-range order of the non-linear\n$\\sigma$-model. In order to clarify whether this is true, we replace the\nfluctuations of the heat bath with Gaussian random variables, and obtain a\nLangevin equation which yields the effective action of the non-linear\n$\\sigma$-model through analyzing the Fokker-Planck equation. It turns out that\nthe fluctuations indeed destroy the long-range order of the non-linear\n$\\sigma$-model within a mean field approximation estimating a critical point,\nwhereas for the corresponding U(1) gauge theory, the phase transition to the\nmassless phase remains against the fluctuations."
    },
    {
        "anchor": "Remarks on correlators of Polyakov Loops: Polyakov loop eigenvalues and their N-dependence are studied in 2 and 4\ndimensional SU(N) YM theory. The connected correlation function of the single\neigenvalue distributions of two separated Polyakov loops in 2D YM is calculated\nand is found to have a structure differing from the one of corresponding\nhermitian random matrix ensembles. No large $N$ non-analyticities are found for\ntwo point functions in the confining regime. Suggestions are made for\nsituations in which large-N phase transitions involving Polyakov loops might\noccur.",
        "positive": "Singular Vertices and the Triangulation Space of the D-sphere: By a sequence of numerical experiments we demonstrate that generic\ntriangulations of the $D-$sphere for $D>3$ contain one {\\it singular}\n$(D-3)-$simplex. The mean number of elementary $D-$simplices sharing this\nsimplex increases with the volume of the triangulation according to a simple\npower law. The lower dimension subsimplices associated with this\n$(D-3)-$simplex also show a singular behaviour. Possible consequences for the\nDT model of four-dimensional quantum gravity are discussed."
    },
    {
        "anchor": "Simulating the vacuum properties of QCD with dynamical quarks: The vacuum properties of lattice QCD with staggered quarks are investigated\nby an efficient simulation method. I present data for the quark condensate with\nflavor number $N_f=0, ~ 1, ~ 2, ~ 3, ~ 4$ and many quark masses, including the\nvacuum energy in the chiral limit. Obvious sea quark effects are observed in\nsome parameter space. I also describe a mechanism to understand this and a\nformula relating the chiral condensate and zero modes.",
        "positive": "QCD phase diagram with 2-flavor lattice fermion formulations: We propose a new framework for investigating two-flavor lattice QCD with\nfinite temperature and density. We consider the Karsten-Wilczek fermion\nformulation, in which a species-dependent imaginary chemical potential term can\nreduce the number of species to two without losing chiral symmetry. This\nlattice discretization is useful for study on finite-($T$,$\\mu$) QCD since its\ndiscrete symmetries are appropriate for the case. To show its applicability, we\nstudy strong-coupling lattice QCD with temperature and chemical potential. We\nderive the effective potential of the scalar meson field and obtain a critical\nline of the chiral phase transition, which is qualitatively consistent with the\nphenomenologically expected phase diagram. We also discuss that $O(1/a)$\nrenormalization of imaginary chemical potential can be controlled by adjusting\na parameter of a dimension-3 counterterm."
    },
    {
        "anchor": "Fermions on tori in uniform abelian fields: We study Fermi fields defined on tori in the presence of gauge backgrounds\ncarrying non-trivial topology. We show that 2k dimensional field space can\nalternatively be described by fields over a k-dimensional space. This dual\ndescription is particularly natural when the background is uniform and abelian.\nThe reduction in number of dimensions carries over to the lattice. The lattice\nultraviolet regularization induces an infrared regularization of the lower\ndimensional representations. We focus on k=1,2.",
        "positive": "Charmonium-like resonances in coupled $D \\bar D$-$D_s \\bar D_s$\n  scattering: Charmonium-like resonances and bound states with isospin zero and\n$J^{PC}=0^{++},~1^{--},~2^{++},~3^{--}$ are extracted on the lattice. Coupled\n$D\\bar D$ and $D_s\\bar D_s$ scattering suggests three charmonium-like states\nwith $J^{PC}=0^{++}$ in addition to $\\chi_{c0}(1P)$: a so far unobserved $D\\bar\nD$ bound state just below threshold, a conventional resonance likely related to\n$\\chi_{c0}(3860)/\\chi_{c0}(2P)$ and a narrow resonance just below the $D_s\\bar\nD_s$ threshold with a large coupling to $D_s\\bar D_s$ likely related to\n$X(3915)/\\chi_{c0}(3930)$. One-channel $D\\bar D$ scattering renders resonances\nand bound states with $J^{PC}= 1^{--},~2^{++},~3^{--}$ related to the observed\nconventional charmonia. Lattice QCD ensembles from the CLS consortium with\n$m_{\\pi}\\simeq 280$ MeV are utilized."
    },
    {
        "anchor": "A Perturbative Construction of Lattice Chiral Fermions: We perform a renormalization group transformation to construct a lattice\ntheory of chiral fermions. The field variables of the continuum theory are\naveraged over hypercubes to define lattice fields. Integrating out the\ncontinuum variables in perturbation theory we derive a chirally invariant\neffective action for the lattice fields. This is consistent with the\nNielsen-Niniomiya theorem because the effective action is nonlocal. We also\nconstruct the axial current on the lattice and we show that the axial anomaly\nof the continuum theory is reproduced in the Schwinger model. This shows that\nchiral fermions can be regularized on the lattice.",
        "positive": "Nuclear Force from Lattice QCD: The first lattice QCD result on the nuclear force (the NN potential) is\npresented in the quenched level. The standard Wilson gauge action and the\nstandard Wilson quark action are employed on the lattice of the size 16^3\\times\n24 with the gauge coupling beta=5.7 and the hopping parameter kappa=0.1665. To\nobtain the NN potential, we adopt a method recently proposed by CP-PACS\ncollaboration to study the pi pi scattering phase shift. It turns out that this\nmethod provides the NN potentials which are faithful to those obtained in the\nanalysis of NN scattering data. By identifying the equal-time Bethe-Salpeter\nwave function with the Schroedinger wave function for the two nucleon system,\nthe NN potential is reconstructed so that the wave function satisfies the\ntime-independent Schroedinger equation. In this report, we restrict ourselves\nto the J^P=0^+ and I=1 channel, which enables us to pick up unambiguously the\n``central'' NN potential V_{central}(r). The resulting potential is seen to\nposses a clear repulsive core of about 500 MeV at short distance (r < 0.5 fm).\nAlthough the attraction in the intermediate and long distance regions is still\nmissing in the present lattice set-up, our method is appeared to be quite\npromising in reconstructing the NN potential with lattice QCD."
    },
    {
        "anchor": "Controlling Complex Langevin simulations of lattice models by boundary\n  term analysis: One reason for the well known fact that the Complex Langevin (CL) method\nsometimes fails to converge or converges to the wrong limit has been identified\nlong ago: it is insufficient decay of the probability density either near\ninfinity or near poles of the drift, leading to boundary terms that spoil the\nformal argument for correctness. To gain a deeper understanding of this\nphenomenon, in a previous paper we have studied the emergence of such boundary\nterms thoroughly in a simple model, where analytic results can be compared with\nnumerics. Here we continue this type of analysis for more physically\ninteresting models, focusing on the boundaries at infinity. We start with\nabelian and non-abelian one-plaquette models, then we proceed to a Polyakov\nchain model and finally to high density QCD (HDQCD) and the 3D XY model. We\nshow that the direct estimation of the systematic error of the CL method using\nboundary terms is in principle possible.",
        "positive": "Dimensional regularization of Schrodinger Functional correlation\n  functions: The matching between Schrodinger Functional renormalization schemes and\nconventional perturbative schemes is usually done using an intermediate lattice\nscheme. We propose to do the matching directly. This requires the perturbative\nevaluation of Schrodinger Functional correlation functions in the continuum. We\nuse dimensional regularization but due to the lack of translational invariance\nin the Euclidean time direction, we employ a general technique introduced by\nLuscher. In this talk I describe this technique and its application to the\none-loop expansion of correlation functions used in the definition of the\nrenormalized quark mass in the Schrodinger Functional scheme. The divergent\nparts are identified and the computation of finite parts is in progress."
    },
    {
        "anchor": "The Effect of the Low Energy Constants on the Spectral Properties of the\n  Wilson Dirac Operator: We summarize recent analytical results obtained for lattice artifacts of the\nnon-Hermitian Wilson Dirac operator. Hereby we discuss the effect of all three\nlow energy constants. In particular we study the limit of small lattice spacing\nand also consider the regime of large lattice spacing which is closely related\nto the mean field limit. Thereby we extract simple relations between measurable\nquantities like the average number of additional real modes and the low energy\nconstants. These relations may improve the fitting for the low energy\nconstants.",
        "positive": "Towards a Many-Body Treatment of Hamiltonian Lattice SU(N) Gauge Theory: We develop a consistent approach to Hamiltonian lattice gauge theory, using\nthe maximal-tree gauge. The various constraints are discussed and implemented.\nAn independent and complete set of variables for the colourless sector is\ndetermined. A general scheme to construct the eigenstates of the electric\nenergy operator using a symbolic method is described. It is shown how the\none-plaquette problem can be mapped onto a N-fermion problem. Explicit\nsolutions for U(1), SU(2), SU(3), SU(4), and SU(5) lattice gauge theory are\nshown."
    },
    {
        "anchor": "Finite T Electroweak Phase Transition on the Lattice: This talk reviews recent lattice results on the high $T$ electroweak phase\ntransition. A remarkably accurate picture emerges: a) the transition is of\nfirst order for $m_H \\lsim 80$GeV and vanishes for larger $m_H$; b) transition\ntemperature, latent heat and interface tension are known, as well as c) the\nproperties of the broken and symmetric phases. New developments in the\nsphaleron rate calculations are discussed.",
        "positive": "Some continuum physics results from the lattice V-A correlator: We present preliminary results on extractions of the chiral LECs L_10 and\nC_87 and constraints on the excited pseudoscalar state pi(1300) and pi(1800)\ndecay constants obtained from an analysis of lattice data for the flavor ud\nlight quark V-A correlator. A comparison of the results for the correlator to\nthe corresponding mildly-model-dependent continuum results (based primarily on\nexperimental hadronic tau decay data) is also given"
    },
    {
        "anchor": "Monte Carlo Hamiltonian: We suggest how to construct an effective low energy Hamiltonian via Monte\nCarlo starting from a given action. We test it by computing thermodynamical\nobservables like average energy and specific heat for simple quantum systems.",
        "positive": "D Pi scattering and D meson resonances from lattice QCD: The masses and widths of the broad scalar D_0^*(2400) and the axial D_1(2430)\ncharmed-light resonances are extracted by simulating the corresponding D Pi and\nD* Pi scattering on the lattice. The resonance parameters are obtained using a\nBreit-Wigner fit of the elastic phase shifts. The resulting D_0^*(2400) mass is\n351+/-21 MeV above the spin-average 1/4(m_D+3m_{D*}), in agreement with the\nexperimental value of 347+/-29 MeV above. The resulting D_0^* to D Pi coupling\ng^{lat}=2.55+/-0.21 GeV is close to the experimental value g^{exp}<=1.92+/-0.14\nGeV, where g parametrizes the width $\\Gamma\\equiv g^2p^*/s$. The resonance\nparameters for the broad D_1(2430) are also found close to the experimental\nvalues; these are obtained by appealing to the heavy quark limit, where the\nneighboring resonance D_1(2420) is narrow. The calculated I=1/2 scattering\nlengths are a_0=0.81+/-0.14 fm for D Pi and a_0=0.81+/-0.17 fm for D* Pi\nscattering. The simulation of the scattering in these channels incorporates\nquark-antiquark as well as multi-hadron interpolators, and the distillation\nmethod is used for contractions. In addition, the ground and several excited\ncharm-light and charmonium states with various J^P are calculated using\nstandard quark-antiquark interpolators. Our simulations are done in lattice QCD\nwith two-dynamical light quarks at a mass corresponding to m_\\pi\\approx 266\nMeV."
    },
    {
        "anchor": "First moment of the flavour octet nucleon parton distribution function\n  using lattice QCD: We perform a lattice computation of the flavour octet contribution to the\naverage quark momentum in a nucleon, $\\la x\\ra^{(8)}_{\\mu^2 = 4 \\gev^2}$. In\nparticular, we fully take the disconnected contributions into account in our\nanalysis for which we use a generalization of the technique developed in\n\\cite{Dinter:2012tt}. We investigate systematic effects with a particular\nemphasis on the excited states contamination. We find that in the\nrenormalization free ratio $\\frac{\\la x \\ra^{(3)}}{\\la x \\ra^{(8)}}$ (with $\\la\nx \\ra^{(3)}$ the non-singlet moment) the excited state contributions cancel to\na large extend making this ratio a promising candidate for a comparison to\nphenomenological analyses. Our final result for this ratio is in agreement with\nthe phenomenological value and we find, including systematic errors, $\\frac{\\la\nx \\ra^{(3)}}{\\la x \\ra^{(8)}} = 0.39(1)(4)$.",
        "positive": "Static-static-light-light tetraquarks in lattice QCD: I report on a lattice computation of the energy of a system of two light\nquarks and two static antiquarks as a function of the separation of the static\nantiquarks. In terms of hadrons such a system corresponds to a pair of B mesons\nand its energy to the hadronic potential. I present selected results for\ndifferent isospin, spin and parity combinations of the individual B mesons\nmainly focusing on those channels relevant to determine, whether two B mesons\nmay form a bound tetraquark state."
    },
    {
        "anchor": "Strong-coupling expansion of lattice O(N) sigma models: We report progress in the computation and analysis of strong-coupling series\nof two- and three-dimensional ${\\rm O}(N)$ $\\sigma$ models. We show that,\nthrough a combination of long strong-coupling series and judicious choice of\nobservables, one can compute continuum quantities reliably and with a precision\nat least comparable with the best available Monte Carlo data.",
        "positive": "Lattice QCD results on soft and hard probes of strongly interacting\n  matter: We present recent results from lattice QCD relevant for the study of strongly\ninteracting matter as it is produced in heavy ion collision experiments. The\nequation of state at non-vanishing density from a Taylor expansion up to\n$6^{th}$ order will be discussed for a strangeness neutral system and using the\nexpansion coefficients of the series limits on the critical point are\nestimated. Chemical freeze-out temperatures from the STAR and ALICE\nCollaborations will be compared to lines of constant physics calculated from\nthe Taylor expansion of QCD bulk thermodynamic quantities. We show that\nqualitative features of the $\\sqrt{s_{NN}}$ dependence of skewness and kurtosis\nratios of net proton-number fluctuations measured by the STAR Collaboration can\nbe understood from QCD results for cumulants of conserved baryon-number\nfluctuations. As an example for recent progress towards the determination of\nspectral and transport properties of the QGP from lattice QCD, we will present\nconstraints on the thermal photon rate determined from a spectral\nreconstruction of continuum extrapolated lattice correlation functions in\ncombination with input from most recent perturbative calculations."
    },
    {
        "anchor": "Large-$N$ $SU(N)$ Yang-Mills theories with milder topological freezing: We simulate $4d$ $SU(N)$ pure-gauge theories at large $N$ using a parallel\ntempering scheme that combines simulations with open and periodic boundary\nconditions, implementing the algorithm originally proposed by Martin Hasenbusch\nfor $2d$ $CP^{N-1}$ models. That allows to dramatically suppress the\ntopological freezing suffered from standard local algorithms, reducing the\nautocorrelation time of $Q^2$ up to two orders of magnitude. Using this\nalgorithm in combination with simulations at non-zero imaginary $\\theta$ we are\nable to refine state-of-the-art results for the large-$N$ behavior of the\nquartic coefficient of the $\\theta$-dependence of the vacuum energy $b_2$,\nreaching an accuracy comparable with that of the large-$N$ limit of the\ntopological susceptibility.",
        "positive": "An insight on the Proof of Orientifold Planar Equivalence on the Lattice: In a recent paper, Armoni, Shifman and Veneziano (ASV) gave a formal\nnon-perturbative proof of planar equivalence between the bosonic sectors of\nSU(N) super Yang-Mills theory and of a gauge theory with a massless quark in\nthe antisymmetric two-indexes representation. In the case of three colors, the\nlatter theory is nothing but one-flavor QCD. Numerical simulations are\nnecessary to test the validity of that proof and to estimate the size of 1/N\ncorrections. As a first step towards numerical simulations, I will give a\nlattice version of the ASV proof of orientifold planar equivalence in the\nstrong-coupling and large-mass phase."
    },
    {
        "anchor": "$q$ deformed formulation of Hamiltonian SU(3) Yang-Mills theory: We study $\\mathrm{SU}(3)$ Yang-Mills theory in $(2+1)$ dimensions based on\nnetworks of Wilson lines. With the help of the $q$ deformation, networks\nrespect the (discretized) $\\mathrm{SU}(3)$ gauge symmetry as a quantum group,\ni.e., $\\mathrm{SU}(3)_k$, and may enable implementations of $\\mathrm{SU}(3)$\nYang-Mills theory in quantum and classical algorithms by referring to those of\nthe stringnet model. As a demonstration, we perform a mean-field computation of\nthe groundstate of $\\mathrm{SU}(3)_k$ Yang-Mills theory, which is in good\nagreement with the conventional Monte Carlo simulation by taking sufficiently\nlarge $k$. The variational ansatz of the mean-field computation can be\nrepresented by the tensor networks called infinite projected entangled pair\nstates. The success of the mean-field computation indicates that the essential\nfeatures of Yang-Mills theory are well described by tensor networks, so that\nthey may be useful in numerical simulations of Yang-Mills theory.",
        "positive": "A Quantum Perfect Lattice Action for Monopoles and Strings: A quantum perfect lattice action in four dimensions can be derived\nanalytically as a renormalized trajectory when we perform a block spin\ntransformation of monopole currents in a simple but non-trivial case of\nquadratic monopole interactions. The spectrum of the lattice theory is\nidentical to that of the continuum theory. The perfect monopole action is\ntransformed exactly into a lattice action of a string model. A perfect operator\nevaluating a static potential between electric charges is also derived\nexplicitly. If the monopole interactions are weak as in the case of infrared\nSU(2) QCD, the string interactions become strong. The static potential and the\nstring tension is estimated analytically by the use of the strong coupling\nexpansion and the continuum rotational invariance is restored completely."
    },
    {
        "anchor": "Some new results on an old controversy: is perturbation theory the\n  correct asymptotic expansion in nonabelian models?: Several years ago it was found that perturbation theory for two-dimensional\nO(N) models depends on boundary conditions even after the infinite volume limit\nhas been taken termwise, provided $N>2$. There ensued a discussion whether the\nboundary conditions introduced to show this phenomenon were somehow anomalous\nand there was a class of `reasonable' boundary conditions not suffering from\nthis ambiguity. Here we present the results of some computations that may be\ninterpreted as giving some support for the correctness of perturbation theory\nwith conventional boundary conditions; however the fundamental underlying\nquestion of the correctness of perturbation theory in these models and in\nparticular the perturbative $\\beta$ function remain challenging problems of\nmathematical physics.",
        "positive": "Truncated Perfect Actions for Staggered Fermions: We discuss the behavior of free perfect staggered fermions and truncated\nversions thereof. The study includes flavor non-degenerate masses. We suggest a\nnew blocking scheme, which provides excellent locality of the perfect lattice\naction. A truncation procedure adequate for the structure of staggered fermions\nis applied. We consider spectral and thermodynamic properties and compare\ntruncated perfect actions, Symanzik improved and standard staggered fermions in\ntwo and four dimensions."
    },
    {
        "anchor": "The spectral dimension of non-generic branched polymers: We show that the spectral dimension on non-generic branched polymers with\npositive susceptibility exponent is given by $d_s=2/(1+\\gamma)$. For those\nmodels with $\\gamma<0$ we find that $d_s=2$.",
        "positive": "Parameter Tuning of Three-Flavor Dynamical Anisotropic Clover Action: In this work, we perform parameter tuning with dynamical anisotropic clover\nlattices using the Schr\\\"odinger functional and stout-smearing in the fermion\nfield. We find that $\\xi_R/\\xi_0$ is relatively close to 1 in our parameter\nsearch, which allows us to fix $\\xi_0$ in our runs. We proposed to determine\nthe gauge and fermion anisotropy in a Schr\\\"odinger-background small box using\nWilson loop ratios and PCAC masses. We demonstrate that these ideas are\nequivalent to but more efficient than the conventional meson dispersion\napproach. The spatial and temporal clover coefficients are fixed to the\ntree-level tadpole-improved clover values, and we demonstrate that they satisfy\nthe nonperturbative condition determined by Schr\\\"odinger functional method."
    },
    {
        "anchor": "Quantum computing for lattice supersymmetry: Quantum computing promises the possibility of studying the real-time dynamics\nof nonperturbative quantum field theories while avoiding the sign problem that\nobstructs conventional lattice approaches. Current and near-future quantum\ndevices are severely limited by noise, making investigations of simple\nlow-dimensional lattice systems ideal testbeds for algorithm development.\nConsidering simple supersymmetric systems, such as supersymmetric quantum\nmechanics with different superpotentials, allows for the analysis of phenomena\nlike dynamical supersymmetry breaking. We present ongoing work applying quantum\ncomputing techniques to study such theories, targeting real-time dynamics and\nsupersymmetry breaking effects.",
        "positive": "The Consequences of Non-Normality: The non-normality of Wilson-type lattice Dirac operators has important\nconsequences - the application of the usual concepts from the textbook\n(hermitian) quantum mechanics should be reconsidered. This includes an\nappropriate definition of observables and the refinement of computational\ntools. We show that the truncated singular value expansion is the optimal\napproximation to the inverse operator D^{-1} and we prove that due to the\ngamma_5-hermiticity it is equivalent to gamma_5 times the truncated eigenmode\nexpansion of the hermitian Wilson-Dirac operator."
    },
    {
        "anchor": "Numerical methods for the sign problem in Lattice Field Theory: The great majority of algorithms employed in the study of lattice field\ntheory are based on Monte Carlo's importance sampling method, i.e. on\nprobability interpretation of the Boltzmann weight. Unfortunately in many\ntheories of interest one cannot associated a real and positive weight to every\nconfiguration, that is because their action is explicitly complex or because\nthe weight is multiplied by some non positive term. In this cases one says that\nthe theory on the lattice is affected by the sign problem. An outstanding\nexample of sign problem preventing a quantum field theory to be studied, is QCD\nat finite chemical potential. Whenever the sign problem is present, standard\nMonte Carlo methods are problematic to apply and, in general, new approaches\nare needed to explore the phase diagram of the complex theory. Here we will\nreview three of the main candidate methods to deal with the sign problem,\nnamely complex Langevin dynamics, Lefschetz thimbles and density of states\nmethod. We will first study complex Langevin dynamics, combined with the gauge\ncooling method, on the one-dimensional Polyakov line model, and then we will\napply it to pure gauge Yang-Mills theory with a topological theta-term. It\nfollows a comparison between complex Langevin dynamics and the Lefschetz\nthimbles method on three toy models, which are the quartic model, the U(1)\none-link model with a mu dependent determinant, and the SU(2) non abelian\none-link model with complex beta parameter. Lastly, we introduce the density of\nstate method, based on the LLR algorithm, and we will employ it in the study of\nthe relativistic Bose gas at finite chemical potential.",
        "positive": "Renormalization of asymmetric staple-shaped Wilson-line operators in\n  lattice and continuum perturbation theory: In this work, we study the renormalization of nonlocal quark bilinear\noperators containing an asymmetric staple-shaped Wilson line at the one-loop\nlevel in both lattice and continuum perturbation theory. These operators enter\nthe first-principle calculation of transverse momentum-dependent parton\ndistribution functions (TMDPDFs) in lattice QCD using the formulation of Large\nMomentum Effective Theory. We provide appropriate RI$'$-type conditions that\naddress the power and logarithmic divergences, as well as the mixing among\nstaple operators of different Dirac structures, using a number of different\npossible projectors. A variant of RI$'$, including calculations of rectangular\nWilson loops, which cancel the pinch-pole singularities of the staple operators\nat infinite length and reduce residual power divergences, is also employed. We\ncalculate at one-loop order the conversion matrix, which relates the\nquasi-TMDPDFs in the RI$'$-type schemes to the reference scheme $\\overline{\\rm\nMS}$ for arbitrary values of the renormalization momentum scale and of the\ndimensions of the staple."
    },
    {
        "anchor": "Correlating confinement to topological fluctuations near the crossover\n  transition in QCD: We show the existence of strong (anti)correlations between the topological\nhot spots and the local values of the trace of the Polyakov loop in $2+1$\nflavor QCD with physical quark mass, in the vicinity of the crossover\ntransition corresponding to the simultaneous restoration of chiral symmetry and\ndeconfinement. Using sophisticated lattice techniques, we have carefully\nidentified the topological hot spots using quark zero modes and measured the\nshort-distance fluctuations of the Polyakov loop about them, showing how the\nlatter is repelled quite strongly around the peak of the zero modes. Though we\ncould explain some aspects of these correlations within the instanton-dyon\npicture, our work sets the stage for a larger goal towards a systematic study\nof the role of different topological species that interact with the Polyakov\nloop, establishing the strong connection between topology and confinement.",
        "positive": "Critical region of the finite temperature chiral transition: We study a Yukawa theory with spontaneous chiral symmetry breaking and with a\nlarge number N of fermions near the finite temperature phase transition.\nCritical properties in such a system can be described by the mean field theory\nvery close to the transition point. We show that the width of the region where\nnon-trivial critical behavior sets in is suppressed by a certain power of 1/N.\nOur Monte Carlo simulations confirm these analytical results. We discuss\nimplications for the chiral phase transition in QCD."
    },
    {
        "anchor": "Free energy of an SU(2) monopole-antimonopole pair: We present a high-statistic numerical study of the free energy of a\nmonopole-antimonopole pair in pure SU(2) theory. We find that the\nmonopole-antimonopole interaction potential exhibits a screened behavior, as\none would expect in presence of a monopole condensate. Screening occurs both in\nthe low-temperature, confining phase of the theory, and in the high-temperature\ndeconfined phase, with no evidence of a discontinuity of the screening mass\nacross the transition. The mass of the object responsible for the screening at\nlow temperature is approximately twice the established value for the lightest\nglueball, indicating a prevalent coupling to glueball excitations. At high\ntemperature, the screening mass increases. We contrast the behavior of the\nquantum system with that of the corresponding classical system, where the\nmonopole-antimonopole potential is of the Coulomb type.",
        "positive": "Aspects of Precision Calculations of Nucleon Generalized Form Factors\n  with Domain Wall Fermions on an Asqtad Sea: In order to advance lattice calculations of moments of unpolarized, helicity,\nand transversity distributions, electromagnetic form factors, and generalized\nform factors of the nucleon to a new level of precision, this work investigates\nseveral key aspects of precision lattice calculations. We calculate the number\nof configurations required for constant statistical errors as a function of\npion mass, describe the coherent sink method to help achieve these statistics,\nexamine the statistical correlations between separate measurements, study\ncorrelations in the behavior of form factors at different momentum transfer,\nexamine volume dependence, and compare mixed action results with those using\ncomparable dynamical domain wall configurations. We also show selected form\nfactor results and comment on the QCD evolution of our calculations of the\nflavor non-singlet nucleon angular momentum."
    },
    {
        "anchor": "Applications of flow models to the generation of correlated lattice QCD\n  ensembles: Machine-learned normalizing flows can be used in the context of lattice\nquantum field theory to generate statistically correlated ensembles of lattice\ngauge fields at different action parameters. This work demonstrates how these\ncorrelations can be exploited for variance reduction in the computation of\nobservables. Three different proof-of-concept applications are demonstrated\nusing a novel residual flow architecture: continuum limits of gauge theories,\nthe mass dependence of QCD observables, and hadronic matrix elements based on\nthe Feynman-Hellmann approach. In all three cases, it is shown that statistical\nuncertainties are significantly reduced when machine-learned flows are\nincorporated as compared with the same calculations performed with uncorrelated\nensembles or direct reweighting.",
        "positive": "A perturbative study of the chirally rotated Schr\u00f6dinger Functional\n  in QCD: The chirally rotated Schr\\\"odinger functional ($\\chi$SF) renders the\nmechanism of automatic $O(a)$ improvement compatible with the Schr\\\"odinger\nfunctional (SF) formulation. Here we report on the determination to 1-loop\norder in perturbation theory of the renormalization coefficients necessary to\nachieve automatic $O(a)$ improvement and the boundary improvement coefficients\nneeded to eliminate the extra boundary $O(a)$ effects present in any SF\nformulation. After this is done, we perform a set of tests of automatic $O(a)$\nimprovement and of the universality between standard and chirally rotated SF\nformulations."
    },
    {
        "anchor": "Making the most of Taylor expansion and imaginary chemical potential: We present preliminary results for the curvature of the pseudocritical line\nand susceptibilities in Nf = 2 + 1 flavor QCD. The computations are carried out\non lattice sizes of 16x16x16x4, at matching parameters of early work of the\nBielefeld group. Emphasis is placed on the control of systematic errors, by\ncross-validating results obtained by use of the Taylor expansion and\nmeasurements at imaginary chemical potential. To this end, we generalize the\nmagnetic equation of state to the analysis of the number density, and we extend\nit to imaginary values of the chemical potential.",
        "positive": "Monte Carlo Methods for the Self-Avoiding Walk: This article is a pedagogical review of Monte Carlo methods for the\nself-avoiding walk, with emphasis on the extraordinarily efficient algorithms\ndeveloped over the past decade."
    },
    {
        "anchor": "Study of Critical Slowing-Down in $SU(2)$ Landau Gauge Fixing: We study the problem of critical slowing-down for gauge-fixing algorithms\n(Landau gauge) in $SU(2)$ lattice gauge theory on $2$ and $4$ dimensional\nlattices, both numerically and analytically. We consider five such algorithms,\nand we measure four different observables. A detailed discussion and analysis\nof the tuning of these algorithms is also presented.",
        "positive": "Matching effective chiral Lagrangians with dimensional and lattice\n  regularization: We compute the free energy in the presence of a chemical potential coupled to\na conserved charge in effective O($n$) scalar field theory (without explicit\nsymmetry breaking terms) to NNL order for asymmetric volumes in general\n$d$--dimensions, using dimensional (DR) and lattice regularizations. This\nyields relations between the 4-derivative couplings appearing in the effective\nactions for the two regularizations, which in turn allows us to translate\nresults, e.g. the mass gap in a finite periodic box in $d=3+1$ dimensions, from\none regularization to the other. Consistency is found with a new direct\ncomputation of the mass gap using DR. For the case $n=4, d=4$ the model is the\nlow-energy effective theory of QCD with $N_{\\rm f}=2$ massless quarks. The\nresults can thus be used to obtain estimates of low energy constants in the\neffective chiral Lagrangian from measurements of the low energy observables,\nincluding the low lying spectrum of $N_{\\rm f}=2$ QCD in the $\\delta$--regime\nusing lattice simulations, as proposed by Peter Hasenfratz, or from the\nsusceptibility corresponding to the chemical potential used."
    },
    {
        "anchor": "Nonperturbative renormalization of asymmetric staple-shaped operators in\n  twisted mass lattice QCD: Staple-shaped Wilson line operators are necessary for the study of transverse\nmomentum-dependent parton distribution functions (TMDPDFs) in lattice QCD and\nbeyond. In this work, we study the renormalization of such operators in the\ngeneral case of an asymmetric staple. We analyze the mixing pattern of these\noperators using their symmetry properties, where we find that the possible\nmixing is restricted within groups of four operators. We then present numerical\nresults using the regularization independent momentum subtraction (RI/MOM)\nscheme to study the importance of mixing using one operator in particular, the\n$\\gamma_0$ operator. Based on these results, we consider the short distance\nratio (SDR) scheme, which is desirable in the absence of mixing. Finally, we\ninvestigate a variant of the RI/MOM scheme, where the renormalization factors\nare computed at short distances.",
        "positive": "On the efficiency of stochastic volume sources for the determination of\n  light meson masses: We investigate the efficiency of single timeslice stochastic sources for the\ncalculation of light meson masses on the lattice as one varies the quark mass.\nSimulations are carried out with Nf = 2 flavours of non-perturbatively O(a)\nimproved Wilson fermions for pion masses in the range of 450 - 760 MeV. Results\nfor pseudoscalar and vector meson two-point correlation functions computed\nusing stochastic as well as point sources are presented and compared. At fixed\ncomputational cost the stochastic approach reduces the variance considerably in\nthe pseudoscalar channel for all simulated quark masses. The vector channel is\nmore affected by the intrinsic stochastic noise. In order to obtain stable\nestimates of the statistical errors and a more pronounced plateau for the\neffective vector meson mass, a relatively large number of stochastic sources\nmust be used."
    },
    {
        "anchor": "A lattice NRQCD calculation of the $B^0-\\bar{B}^0$ mixing parameter B_B: We present a lattice calculation of the B meson B-parameter B_B using the\nNRQCD action. The heavy quark mass dependence is explicitly studied over a mass\nrange between m_b and 4m_b with the $O(1/m_Q)$ and $O(1/m_Q^2)$ actions. We\nfind that the ratios of lattice matrix elements $<O_N^{lat}>/<A_0^{lat}>^2$ and\n$<O_S^{lat}>/<A_0^{lat}>^2$, which contribute to B_B through mixing, have\nsignificant $1/m_Q$ dependence while that of the leading operator\n$<O_L^{lat}>/<A_0^{lat}>^2$ has little $1/m_Q$ effect. The combined result for\nB_B(m_b) has small but non-zero mass dependence, and the B_B(m_b) becomes\nsmaller by 10% with the 1/m_Q correction compared to the static result. Our\nresult in the quenched approximation at \\beta=5.9 is B_{B_d}(5 GeV) =\n0.75(3)(12), where the first error is statistical and the second is a\nsystematic uncertainty.",
        "positive": "Calculating the $K_L-K_S$ mass difference and $\u03b5_K$ to\n  sub-percent accuracy: The real and imaginary parts of the $K_L-K_S$ mixing matrix receive\ncontributions from all three charge-2/3 quarks: up, charm and top. These give\nboth short- and long-distance contributions which are accessible through a\ncombination of perturbative and lattice methods. We will discuss a strategy to\ncompute both the mass difference, $\\Delta M_K$ and $\\epsilon_K$ to sub-percent\naccuracy, looking in detail at the contributions from each of the three CKM\nmatrix element products $V_{id}^*V_{is}$ for $i=u, c$ and $t$ as described in\nRef. [1]"
    },
    {
        "anchor": "Four-dimensional Yang-Mills theory with a three-dimensional fermion\n  membrane: We study the four-dimensional Yang-Mills theory in the presence of a\nthree-dimensional membrane of fermions by lattice Monte Carlo simulations. We\nanalyze the phase structure of this theory at finite temperature. Below the\nphase transition temperature of the pure Yang-Mills theory, we obtain an\nunconventional phase with spatially-nonuniform vacuum. In this phase, the\nexpectation value of the Polyakov loop is finite on the membrane, and it\nexponentially decays to zero outside the membrane.",
        "positive": "Origin of fermion masses without spontaneous symmetry breaking: Using a simple three dimensional lattice four-fermion model we argue that\nmassless fermions can become massive due to interactions without the need for\nany spontaneous symmetry breaking. Using large scale Monte Carlo calculations\nwithin our model, we show that this non-traditional mass generation mechanism\noccurs at a second order quantum critical point that separates phases with the\nsame symmetries. Universality then suggests that the new origin for the fermion\nmass should be of wide interest."
    },
    {
        "anchor": "Application of fixed scale approach to static quark free energies in\n  quenched and 2+1 flavor lattice QCD with improved Wilson quark action: Free energies between static quarks and Debye screening masses in the\nquark-gluon plasma are studied on the basis of Polyakov-line correlations in\nlattice simulations of 2+1 flavors QCD with the renormalization-group improved\ngluon action and the $O(a)$-improved Wilson quark action. We perform\nsimulations at $m_{\\rm PS}/m_{\\rm V} = 0.63$ (0.74) for light (strange) flavors\nwith lattice sizes of $32^3 \\times N_t$ with $N_t=4$--12. We adopt the\nfixed-scale approach, where temperature can be varied without changing the\nspatial volume and renormalization factor. We find that, at short distance, the\nfree energies of static quarks in color-singlet channel converge to the\nstatic-quark potential evaluated from the Wilson-loop at zero-temperature, in\naccordance with the expected insensitivity of short distance physics to the\ntemperature. At long distance, the free energies of static quarks approach to\ntwice the single-quark free energies, implying that the interaction between\nstatic quarks is fully screened. The screening properties can be well described\nby the screened Coulomb form with appropriate Casimir factor at high\ntemperature. We also discuss a limitation of the fixed-scale approach at high\ntemperature.",
        "positive": "On the magnetic equation of state in (2+1)-flavor QCD: A first study of critical behavior in the vicinity of the chiral phase\ntransition of (2+1)-flavor QCD is presented. We analyze the quark mass and\nvolume dependence of the chiral condensate and chiral susceptibilities in QCD\nwith two degenerate light quark masses and a strange quark. The strange quark\nmass (m_s) is chosen close to its physical value; the two degenerate light\nquark masses (m_l) are varied in a wide range 1/80 \\le m_l/m_s \\le 2/5, where\nthe smallest light quark mass value corresponds to a pseudo-scalar Goldstone\nmass of about 75 MeV. All calculations are performed with staggered fermions on\nlattices with temporal extent Nt=4. We show that numerical results are\nconsistent with O(N) scaling in the chiral limit. We find that in the region of\nphysical light quark mass values, m_l/m_s \\simeq 1/20, the temperature and\nquark mass dependence of the chiral condensate is already dominated by\nuniversal properties of QCD that are encoded in the scaling function for the\nchiral order parameter, the magnetic equation of state. We also provide\nevidence for the influence of thermal fluctuations of Goldstone modes on the\nchiral condensate at finite temperature. At temperatures below, but close to\nthe chiral phase transition at vanishing quark mass, this leads to a\ncharacteristic dependence of the light quark chiral condensate on the square\nroot of the light quark mass."
    },
    {
        "anchor": "$B^0_s - \\bar{B^0_s}$ Mixing Parameters from Unquenched Lattice QCD: We determine hadronic matrix elements relevant for the mass and width\ndifferences, $\\Delta M_s$ & $\\Delta \\Gamma_s$ in the $B^0_s - \\bar{B^0_s}$\nmeson system using fully unquenched lattice QCD. We employ the MILC\ncollaboration gauge configurations that include $u$, $d$ and $s$ sea quarks\nusing the improved staggered quark (AsqTad) action and a highly improved gluon\naction. We implement the valence $s$ quark also with the AsqTad action and use\nNonrelativistic QCD for the valence $b$ quark. For the nonperturbative QCD\ninput into the Standard Model expression for $\\Delta M_s$ we find $f_{B_s}\n\\sqrt{\\hat{B}_{B_s}} = 0.281(21)$GeV. Results for four-fermion operator matrix\nelements entering Standard Model formulas for $\\Delta \\Gamma_s$ are also\npresented.",
        "positive": "Monte Carlo study of Lefschetz thimble structure in one-dimensional\n  Thirring model at finite density: We consider the one-dimensional massive Thirring model formulated on the\nlattice with staggered fermions and an auxiliary compact vector (link) field,\nwhich is exactly solvable and shows a phase transition with increasing the\nchemical potential of fermion number: the crossover at a finite temperature and\nthe first order transition at zero temperature. We complexify its\npath-integration on Lefschetz thimbles and examine its phase transition by\nhybrid Monte Carlo simulations on the single dominant thimble. We observe a\ndiscrepancy between the numerical and exact results in the crossover region for\nsmall inverse coupling $\\beta$ and/or large lattice size $L$, while they are in\ngood agreement at the lower and higher density regions. We also observe that\nthe discrepancy persists in the continuum limit keeping the temperature finite\nand it becomes more significant toward the low-temperature limit. This\nnumerical result is consistent with our analytical study of the model's thimble\nstructure. And these results imply that the contributions of subdominant\nthimbles should be summed up in order to reproduce the first order transition\nin the low-temperature limit."
    },
    {
        "anchor": "Dilaton Chiral Perturbation Theory - Determining Mass and Decay Constant\n  of Technidilaton on the Lattice: We propose a scale-invariant chiral perturbation theory of the\npseudo-Nambu-Goldstone bosons of the chiral symmetry (pion \"pi\") as well as the\nscale symmetry (dilaton \"phi\") for the large N_f QCD. The resultant dilaton\nmass M_phi reads M_phi^2= m_phi^2 + (3-gamma_m)(1+gamma_m)/4 (2 N_f\nF_pi^2/F_phi^2) m_pi^2 + (chiral log corrections), where m_phi, m_pi, gamma_m,\nF_pi and F_phi are the dilaton mass in the chiral limit, the pion mass, mass\nanomalous dimension, decay constants of pi and phi, respectively. The chiral\nextrapolation of the lattice data on M_phi^2 vs m_pi^2 plot then simultaneously\ndetermines (m_phi, F_phi) of the technidilaton in the walking technicolor with\ngamma_m =~1. The chiral logarithmic corrections are explicitly given.",
        "positive": "QCD calculations with optical lattices?: By trapping cold polarizable atoms in periodic potentials created by crossed\nlaser beams, it is now possible to experimentally create \"clean\" lattice\nsystems. Experimentalists have successfully engineered local and\nnearest-neighbor interactions that approximately recreate Hubbard-like models\non table tops. I discuss the possibility of using this new technology in the\ncontext of lattice gauge theory and in particular, relativistic dispersion\nrelations, flavor symmetry, functional derivatives and emerging local gauge\nsymmetry."
    },
    {
        "anchor": "Strongly Interacting Higgs Sector in the Minimal Standard Model?: The triviality Higgs mass bound is studied {\\it without} lattice regulator in\nthe spontaneously broken phase of the four dimensional O(4) symmetric scalar\nfield theory with quartic self-interaction. A higher derivative term is\nintroduced in the kinetic energy of the Lagrangian to keep quantum fluctuations\nfinite while preserving all the symmetries of the model. When viewed as a {\\it\nfinite} field theory in continuum space-time, some excitations of the Higgs\nfield have to be quantized with indefinite metric in the Hilbert space. It is\nshown that the associated ghost particles, which exhibit unusual resonance\nproperties, correspond to a complex conjugate pair of Pauli-Villars regulator\nmasses in the euclidean path integral formulation. The phase diagram of the\nO(4) model is determined in a Monte Carlo simulation which interpolates between\nthe hypercubic lattice regulator and the higher derivative regulator in\ncontinuum space-time. The same method can be used to calculate the triviality\nHiggs mass bound without lattice artifacts. In a large-N analysis, when\ncompared with a hypercubic lattice, we find a relative increase in the\ntriviality bound of the higher derivative regulator suggesting a strongly\ninteracting Higgs",
        "positive": "Determining the glue component of the nucleon: Computing the gluon component of momentum in the nucleon is a difficult and\ncomputationally expensive problem, as the matrix element involves a\nquark-line-disconnected gluon operator which suffers from ultra-violet\nfluctuations. But also necessary for a successful determination is the\nnon-perturbative renormalisation of this operator. As a first step we\ninvestigate here this renormalisation in the RI-MOM scheme. Using quenched QCD\nas an example, a statistical signal is obtained in a direct calculation using\nan adaption of the Feynman-Hellmann technique."
    },
    {
        "anchor": "Tempered Lefschetz thimble method and its application to the Hubbard\n  model away from half filling: The tempered Lefschetz thimble method (TLTM) is a parallel-tempering\nalgorithm towards solving the numerical sign problem. It tames both the sign\nand ergodicity problems simultaneously by tempering the system with the flow\ntime of continuous deformations of the integration region. In this article,\nafter reviewing the basics of the TLTM, we explain a new algorithm within the\nTLTM that enables us to estimate the expectation values precisely with a\ncriterion ensuring global equilibrium and the sufficiency of the sample size.\nTo demonstrate the effectiveness of the algorithm, we apply the TLTM to the\nquantum Monte Carlo simulation of the Hubbard model away from half filling on a\ntwo-dimensional lattice of small size, and show that the obtained numerical\nresults agree nicely with exact values.",
        "positive": "Accelerating the solution of families of shifted linear systems with\n  CUDA: We describe the GPU implementation of shifted or multimass iterative solvers\nfor sparse linear systems of the sort encountered in lattice gauge theory. We\nprovide a generic tool that can be used by those without GPU programming\nexperience to accelerate the simulation of a wide array of theories. We stress\ngenericity, which is important to allow the simulation of candidate theories\nfor new physics at LHC, and for the study of various supersymmetric theories.\nWe find significant speed ups, which we conservatively bound below at at least\ntwelve times, that promise to put a variety of research questions within\npractical reach."
    },
    {
        "anchor": "Cluster algorithms: Cluster algorithms for classical and quantum spin systems are discussed. In\nparticular, the cluster algorithm is applied to classical O(N) lattice actions\ncontaining interactions of more than two spins. The performance of the\nmulti-cluster and single--cluster methods, and of the standard and improved\nestimators are compared. (Lecture given at the summer school on `Advances in\nComputer Simulations', Budapest, July 1996.)",
        "positive": "Continuum limit of finite temperature $\u03bb\u03c6^4_3$ from lattice\n  Monte Carlo: The $\\phi^4_3$ model at finite temperature is simulated on the lattice. For\nfixed $N_t$ we compute the transition line for $N_s \\to \\infty$ by means of\nFinite Size Scaling techniques. The crossings of a Renormalization Group\ntrajectory with the transition lines of increasing $N_t$ give a well defined\nlimit for the critical temperature in the continuum. By considering different\nRG trajectories, we compute $T^c/g$ as a function of the renormalized\nparameters."
    },
    {
        "anchor": "Chiral Ward identities, automatic O(a) improvement and the gradient flow: Non-singlet chiral Ward identities for fermionic operators at positive\nflow-time are derived using standard techniques based on local chiral\nvariations of the action and of local operators. The gradient flow formalism is\napplied to twisted mass fermions and it is shown that automatic O(a)\nimprovement for Wilson twisted mass fermions at maximal twist is a property\nvalid also at positive flow-time. A definition of the chiral condensate that is\nmultiplicatively renormalizable and automatically O(a) improved is then\nderived.",
        "positive": "Continuum extrapolation of finite temperature meson correlation\n  functions in quenched lattice QCD: We explore the continuum limit $a\\rightarrow 0$ of meson correlation\nfunctions at finite temperature. In detail we analyze finite volume and lattice\ncut-off effects in view of possible consequences for continuum physics. We\nperform calculations on quenched gauge configurations using the clover improved\nWilson fermion action. We present and discuss simulations on isotropic\n$N_\\sigma^3\\times 16$ lattices with $N_\\sigma=32,48,64,128$ and $128^3 \\times\nN_\\tau$ lattices with $N_\\tau=16,24,32,48$ corresponding to lattice spacings in\nthe range of $0.01 fm \\lsim a \\lsim\\ 0.031 fm$ at $T\\simeq1.45T_c$. Continuum\nlimit extrapolations of vector meson and pseudo scalar correlators are\nperformed and their large distance expansion in terms of thermal moments is\nintroduced. We discuss consequences of this analysis for the calculation of the\nelectrical conductivity of the QGP at this temperature."
    },
    {
        "anchor": "A comprehensive lattice study of SU(3) glueballs: We present a study of the $SU(3)$ glueball spectrum for all $J^{PC}$ values\nat lattice spacings down to $a^{-1}=3.73 (6)$ GeV ($\\beta=6.4$) using lattices\nof size up to $32^4$. We extend previous studies and show that the continuum\nlimit has effectively been reached. The number of clearly identified $J^{PC}$\nstates has been substantially increased. There are no clear signals for\nspin-exotic glueballs below 3 GeV. A comparison with current experimental\nglueball candidates is made.",
        "positive": "Status of Lattice Flavor Physics: This talk reviews recent lattice QCD calculations relevant for quark flavor\nphysics. Since lattice results must be accurate and precise to play a\ndefinitive role in phenomenology, the focus is on unquenched results of\nquantities which can be calculated most reliably."
    },
    {
        "anchor": "Introduction to Lattice Gaugefixing and Effective Quark and Gluon Masses: This talk was presented to a non-lattice audience at the June, 1992 Paris\nWorkshop on QCD Vacuum Structure. We report on the status of quark and gluon\npropagators in quenched, gaugefixed lattice QCD. In Landau gauge we find that\nthe effective quark mass in the chiral limit is $M_q \\sim 350(40)MeV$. Quark\nand gluon propagators, the slope of the quark dispersion relation, and\neffective masses all appear to depend on gauge. A link-chain picture of lattice\ngaugefixing in the color $N\\to\\infty$ and strong coupling limit, where the\nsystem becomes almost solvable, supports the gauge variance of these numerical\nresults. Subscribers will be given one Postscript file, the Figure included.\nLatex and Axis versions available from KY at kyee@rouge.phys.lsu.edu on\nrequest.",
        "positive": "Gap in the Dirac spectrum and quark propagator symmetries in lattice QCD: Recent studies on lattice QCD have shown the emergence of large symmetries at\nhigh temperature. This includes not only the restoration $SU(n_F)_L \\times\nSU(n_F)_R$, but also the effective emergence of an unexpected symmetry group,\nnamely $SU(2)_{CS}$, which contains $U(1)_A$ as subgroup. At the same time, at\nhigh $T$, a gap in Dirac spectrum appears. As it is argued in several works of\n\\textit{L. Glozman et al.}, there should be a connection between a gap in the\nDirac spectrum and the presence of $SU(2)_{CS}$.In this paper, we analyze\nwhether the quark propagator can be invariant under $SU(n_F)_L \\times\nSU(n_F)_R$ and $SU(2)_{CS}$ transformations, in case of a gap in the Dirac\nspectrum, and consequently the invariance of hadron correlators, giving the\ncondition for a quark propagator to be invariant under $SU(2)_{CS}$."
    },
    {
        "anchor": "The quark mass dependence of the pion mass at infinite N: In planar QCD, in two space time dimensions, the meson eigenvalue equation\nhas a nonlocal structure interpretable as resulting from hidden degrees of\nfreedom. The nonlocality can be reconstructed from the functional form of the\npion mass dependence on quark mass within an expansion starting from a special\none dimensional Schroedinger problem. The one dimensional problem makes the\npion mass depend on the quark mass through a simple quadratic relation which is\nshown to be compatible also with numerical data obtained in four dimensions.",
        "positive": "Perfect Lattice Actions for the Gross-Neveu Model: We apply the method of Hasenfratz and Niedermayer to analytically construct\nperfect lattice actions for the Gross--Neveu model. In the large $N$ limit\nthese actions display an exactly perfect scaling, i.e. cut-off artifacts are\ncompletely eliminated even at arbitrarily short correlation length. Also the\nenergy spectrum coincides with the spectrum in the continuum and continuous\ntranslation and rotation symmetries are restored in physical observables. This\nis the first (analytic) construction of an exactly perfect lattice action at\nfinite correlation length."
    },
    {
        "anchor": "Spectral Methods in Causal Dynamical Triangulations: We show recent results of the application of spectral analysis in the setting\nof the Monte Carlo approach to Quantum Gravity known as Causal Dynamical\nTriangulations (CDT), discussing the behavior of the lowest lying eigenvalues\nof the Laplace-Beltrami operator computed on spatial slices. This kind of\nanalysis provides information about running scales of the theory and about the\ncritical behaviour around a possible second order transition in the CDT phase\ndiagram, discussing the implications for the continuum limit.",
        "positive": "Monte Carlo studies of 3d N=6 SCFT via localization method: We perform Monte Carlo study of the 3d N=6 superconformal U(N)*U(N)\nChern-Simons gauge theory (ABJM theory), which is conjectured to be dual to\nM-theory or type IIA superstring theory on certain AdS backgrounds. Our\napproach is based on a localization method, which reduces the problem to the\nsimulation of a simple matrix model. This enables us to circumvent the\ndifficulties in the original theory such as the sign problem and the SUSY\nbreaking on a lattice. The new approach opens up the possibility of probing the\nquantum aspects of M-theory and testing the AdS_4/CFT_3 duality at the quantum\nlevel. Here we calculate the free energy, and confirm the N^{3/2} scaling in\nthe M-theory limit predicted from the gravity side. We also find that our\nresults nicely interpolate the analytical formulae proposed previously in the\nM-theory and type IIA regimes."
    },
    {
        "anchor": "Pion Polarizabilities and Volume Effects in Lattice QCD: We use chiral perturbation theory to study the extraction of pion\nelectromagnetic polarizabilities from lattice QCD. Chiral extrapolation\nformulae are derived for partially quenched QCD, and quenched QCD simulations.\nOn a torus, volume dependence of electromagnetic observables is complicated by\nSO(4) breaking, as well as photon zero-mode interactions. We determine finite\nvolume corrections to the Compton scattering tensor of pions. We argue,\nhowever, that such results cannot be used to ascertain volume corrections to\npolarizabilities determined in lattice QCD with background field methods.\nConnection is lacking because momentum expansions are not permitted in finite\nvolume. Our argument also applies to form factors. Volume effects for\nelectromagnetic moments cannot be deduced from finite volume form factors.",
        "positive": "Lattice QCD study of antiheavy-antiheavy-light-light tetraquarks based\n  on correlation functions with scattering interpolating operators both at the\n  source and at the sink: We present first results of a recently started lattice QCD investigation of\nantiheavy-antiheavy-light-light tetraquark systems including scattering\ninterpolating operators in correlation functions both at the source and at the\nsink. In particular, we discuss the importance of such scattering interpolating\noperators for a precise computation of the low-lying energy levels. We focus on\nthe $\\bar b \\bar b u d$ four-quark system with quantum numbers $I(J^P) =\n0(1^+)$, which has a ground state below the lowest meson-meson threshold. We\ncarry out a scattering analysis using L\\\"uscher's method to extrapolate the\nbinding energy of the corresponding QCD-stable tetraquark to infinite spatial\nvolume. Our calculation uses clover $u$, $d$ valence quarks and NRQCD $b$\nvalence quarks on gauge-link ensembles with HISQ sea quarks that were generated\nby the MILC collaboration."
    },
    {
        "anchor": "MILC Code Performance on High End CPU and GPU Supercomputer Clusters: With recent developments in parallel supercomputing architecture, many core,\nmulti-core, and GPU processors are now commonplace, resulting in more levels of\nparallelism, memory hierarchy, and programming complexity. It has been\nnecessary to adapt the MILC code to these new processors starting with NVIDIA\nGPUs, and more recently, the Intel Xeon Phi processors. We report on our\nefforts to port and optimize our code for the Intel Knights Landing\narchitecture. We consider performance of the MILC code with MPI and OpenMP, and\noptimizations with QOPQDP and QPhiX. For the latter approach, we concentrate on\nthe staggered conjugate gradient and gauge force. We also consider performance\non recent NVIDIA GPUs using the QUDA library.",
        "positive": "B-meson mixing from full lattice QCD with physical u, d, s and c quarks: We present the first lattice QCD calculation of the $B_s$ and $B_d$ mixing\nparameters with physical light quark masses. We use MILC gluon field\nconfigurations that include $u$, $d$, $s$ and $c$ sea quarks at 3 values of the\nlattice spacing and with 3 values of the $u/d$ quark mass going down to the\nphysical value. We use improved NRQCD for the valence $b$ quarks. Preliminary\nresults show significant improvements over earlier values."
    },
    {
        "anchor": "Staggered Diquarks for the Singly Heavy Baryons: In the staggered fermion formulation of lattice QCD, we construct diquark\noperators to be embedded in singly heavy baryons. The group theoretical\nconnections between the continuum and lattice staggered diquark representations\nare established.",
        "positive": "Canonical Quantization of Two Dimensional Gauge Fields: $SU(N)$ gauge fields on a cylindrical spacetime are canonically quantized via\ntwo routes revealing almost equivalent but different quantizations. After\nremoving all continuous gauge degrees of freedom, the canonical coordinate\n$A_\\mu$ (in the Cartan subalgebra $\\h$) is quantized. The compact route, as in\nlattice gauge theory, quantizes the Wilson loop $W$, projecting out gauge\ninvariant wavefunctions on the group manifold $G$. After a Casimir energy\nrelated to the curvature of $SU(N)$ is added to the compact spectrum, it is\nseen to be a subset of the non-compact spectrum. States of the two\nquantizations with corresponding energy are shifted relative each other, such\nthat the ground state on $G$, $\\chi_0(W)$, is the first excited state\n$\\Psi_1(A_\\mu)$ on $\\h$. The ground state $\\Psi_0(A_\\mu)$ does not appear in\nthe character spectrum as its lift is not globally defined on $G$. Implications\nfor lattice gauge theory and the sum over maps representation of two\ndimensional QCD are discussed."
    },
    {
        "anchor": "Spectrum of screening masses in the (3+1)D SU(2) pure gauge theory near\n  the critical temperature: We study the spectrum of screening masses in the deconfined phase of (3+1)D\nSU(2) pure gauge theory near criticality and compare it with the spectrum of\nbound states in the broken symmetry phase of the 3D Ising model, which is\nrelated to the gauge theory by universality.",
        "positive": "Asymptotic scaling from strong coupling: Strong-coupling analysis of two-dimensional chiral models, extended to 15th\norder, allows for the identification of a scaling region where known continuum\nresults are reproduced with great accuracy, and asymptotic scaling predictions\nare fulfilled. The properties of the large-$N$ second-order phase transition\nare quantitatively investigated."
    },
    {
        "anchor": "String-breaking in quenched QCD: We present results on a new operator for the investigation of string-breaking\neffects in quenched SU(2)-colour QCD. The ground state of a spatially-separated\nstatic-light meson-antimeson pair is a combination of a state with two distinct\nmesons, expected to dominate for large separations, and a state where the light\nquarks have annihilated, which contributes at short distances. The cross-over\nbetween these two regimes provides the string-breaking scale.",
        "positive": "Charm Fluctuations and Deconfinement: We establish that the charmed hadrons start dissociating at the chiral\ncrossover temperature, ${T_{pc}}$, leading to the appearance of charm degrees\nfreedom carrying fractional baryon number. Our method is based on analyzing the\nsecond and fourth-order cumulants of charm (${C}$) fluctuations, and their\ncorrelations with baryon number (${B}$), electric charge (${Q}$) and\nstrangeness (${S}$) fluctuations. The first-time calculation of the ${QC}$\ncorrelations on the high statistics datasets of the HotQCD Collaboration\nenables us to disentangle the contributions from different electrically-charged\ncharm subsectors in the hadronic phase. In particular, we see an enhancement\nover the PDG expectation in the fractional contribution of the ${|Q|}=2$ charm\nsubsector to the total charm partial pressure for ${T<T_{pc}}$; this\nenhancement is in agreement with the Quark Model extended Hadron Resonance Gas\n(QM-HRG) model calculations. Furthermore, the agreement of QM-HRG calculations\nwith the projections onto charmed baryonic and mesonic correlations in\ndifferent charm subsectors indicates the existence of not-yet-discovered\ncharmed hadrons in all charm subsectors below ${T_{pc}}$. We aim at determining\nthe relevant degrees of freedom in temperature range ${T_{pc}<T<340 \\text{\nMeV}}$ by assuming the existence of a non-interacting gas of charmed\nquasi-particles composed of meson, baryon and quark-like excitations above\n$T_{pc}$. Our data suggest that the particles with quantum numbers consistent\nwith quarks start appearing at $T_{pc}$."
    },
    {
        "anchor": "The asymptotic approach to the continuum of lattice QCD spectral\n  observables: We consider spectral quantities in lattice QCD and determine the asymptotic\nbehavior of their discretization errors. Wilson fermion with\nO$(a)$-improvement, (M\\\"obius) Domain wall fermion (DWF), and overlap Dirac\noperators are considered in combination with the commonly used gauge actions.\nWilson fermions and DWF with domain wall height $M_5=1+{\\rm O}(g_0^2)$ have the\nsame, approximate, form of the asymptotic cutoff effects: $ K\\,a^2\\left[\\bar\ng^2(a^{-1})\\right]^{0.760}$. A domain wall height $M_5=1.8$, as often used,\nintroduces large mass-dependent $K'(m)\\,a^2\\left[\\bar\ng^2(a^{-1})\\right]^{0.518}$ effects. Massless twisted mass fermions have the\nsame form as Wilson fermions when the Sheikholeslami-Wohlert term [1] is\nincluded. For their mass-dependent cutoff effects we have information on the\nexponents $\\hat\\Gamma_i$ of $\\bar g^2(a^{-1})$ but not for the pre-factors. For\nstaggered fermions there is only partial information on the exponents.\n  We propose that tree-level ${\\rm O}(a^2)$ improvement, which is easy to do\n[2], should be used in the future -- both for the fermion and the gauge action.\nIt improves the asymptotic behavior in all cases.",
        "positive": "Lambda-nucleon force from lattice QCD: We study the $\\Lambda$-nucleon ($\\Lambda N$) force by using lattice QCD. The\nBethe-Salpeter amplitude is calculated for the lowest scattering state of the\n$\\Lambda N$ so as to obtain the $\\Lambda N$ potential. The numerical\ncalculation is twofold: (i) Full lattice QCD by using 2+1 flavor PACS-CS gauge\nconfigurations with, $\\beta=1.9$, corresponding to the lattice spacing of\n$a=0.0907(13)$ fm, on a $32^3\\times 64$ lattice. A set of parameter\n$(\\kappa_{ud},\\kappa_s)=(0.13770,0.13640)$ is used, which corresponds to\n$m_\\pi\\approx 300$ MeV and $m_K\\approx 594$ MeV. The spatial lattice volume\ncorresponds to (2.86 fm)$^3$. (ii) Quenched lattice QCD with $\\beta=5.7$, the\nlattice spacing of $a=0.1416(9)$ fm, on the $32^3\\times48$ lattice. Two sets of\nhopping parameters $(\\kappa_{ud},\\kappa_s)=(0.1665,0.1643),(0.1670,0.1643)$ are\nused. The spatial lattice volume is (4.5 fm)$^3$. For the full QCD, we find\nthat the $\\Lambda p$ has a relatively strong (weak) repulsive core in the\n$^1S_0$ ($^3S_1$) channel at short distance, while the potential has slight\nattractive region at medium distance. The lowest scattering energy in the\nfinite lattice volume is calculated; Slightly negative values obtained in both\nspin channels. For the quenched QCD, we find that the results are qualitatively\nin agreement with those in the full QCD calculation."
    },
    {
        "anchor": "On the U(2) Lattice Gauge Theory: We study the U(2) lattice gauge theory in the pure gauge sector using the\nsimplest action, with determinant and fundamental terms, having the naive\ncontinuum limit of SU(2)$\\times$U(1). We determine part of the phase diagram of\nthe model and find a first-order critical line which goes through the U(1)\ncritical point. We show how to deduce both the order parameter of the\nfirst-order transition and the U(2) renormalization group flow from the lattice\npotential in the determinant and fundamental representations. We give evidence\nthat a Monte-Carlo simulation of the model is indeed consistent with the\nsymmetric SU(2)$\\times$U(1) continuum limit in the weak coupling pertubative\nregime.",
        "positive": "Kosterlitz-Thouless transition on the worldsheet of the QCD string: We investigate the properties of the QCD string in the Euclidean SU(N) pure\ngauge theory when the space-time dimensions transverse to it are periodic. We\npropose a generalisation of the Luscher-Weisz effective string action for the\nflux-tube energy levels at finite L_perp. As the size of one transverse\ndimension is varied, we predict a Kosterlitz-Thouless transition of the\nworldsheet field theory driven by vortices, after which the periodic component\nof the worldsheet displacement vector develops a mass gap and the effective\ncentral charge drops by one unit. The universal properties of the transition\nare emphasized."
    },
    {
        "anchor": "The 4-D Layer Phase as a Gauge Field Localization: Extensive Study of\n  the 5-D Anisotropic U(1) Gauge Model on the Lattice: We study a 4+1 dimensional pure Abelian Gauge model on the lattice with two\nanisotropic couplings independent of each other and of the coordinates. A first\nexploration of the phase diagram using mean field approximation and monte carlo\ntechniques has demonstrated the existence of a new phase, the so called Layer\nphase, in which the forces in the 4-D subspace are Coulomb-like while in the\ntransverse direction (fifth dimension) the force is confining. This allows the\npossibility of a gauge field localization scheme. In this work the use of\nbigger lattice volumes and higher statistics confirms the existence of the\nLayer phase and furthermore clarifies the issue of the phase transitions'\norder. We show that the Layer phase is separated from the strongly coupled\nphase by a weak first order phase transition. Also we provide evidence that the\nLayer phase is separated by the five-dimensional Coulomb phase with a second\norder phase transition and we give a first estimation of the critical\nexponents.",
        "positive": "QCD Equation of State at nonzero baryon density in external magnetic\n  field: This paper is devoted to the study of QCD equation of state in external\nmagnetic field and nonzero baryon density. Our study is carried out by means of\nlattice simulation with 2+1 dynamical staggered quarks at the physical masses.\nThe simulation is conducted at imaginary baryon chemical potential what allowed\nus to overcome the sign problem. We expand the pressure in the baryon imaginary\nchemical potential and study three leading nonzero coefficients in this\nexpansion. These coefficients were calculated for the following values of\nmagnetic field: $eB=0.3$, $0.6$, $1.2$ GeV$^2$ with the lattice sizes\n$8\\times32^3$, $10\\times40^3$, $12\\times48^3$. Using these data we take\ncontinuum limit for the coefficients. Our results indicate considerable\nenhancement of the expansion coefficients by the magnetic field."
    },
    {
        "anchor": "About the solution of the numerical instability for topological solitons\n  with long range interaction: The computations of solutions of the field equations in the Model of\nTopological Particles, formulated with a scalar SU(2)-field, have shown\ninstabilities leading to discrepancies between the numerical and analytical\nsolutions. We identify the origin of these deviations in misalignments of the\nrotational axes corresponding to the SU(2) elements. The system of a single\nsoliton we use as an example to show that a constraint suppressing the\nwave-like disturbances is able to lead to excellent agreement between the\nresult of the numerical minimisation procedure and the analytical solution.",
        "positive": "The eigenvalue spectrum for dynamical Chirally Improved fermions: We study the eigenvalues of Dirac operators in QCD with two mass degenerate\ndynamical fermions. The gauge configurations have been obtained with HMC and\nthe so-called Chirally Improved fermionic action. We compare eigenvalues\nobtained for the overlap Dirac operator on these configurations with those for\nthe Chirally Improved (CI) operator (studied earlier). Results of Random Matrix\nTheory allow us to determine the chiral condensate."
    },
    {
        "anchor": "Curved domain-wall fermion and its anomaly inflow: We investigate the effect of $U (1)$ gauge field on lattice fermion systems\nwith a curved domain-wall mass term. In the same way as the conventional flat\ndomain-wall fermion, the chiral edge modes appear localized at the wall, whose\nDirac operator contains the induced gravitational potential as well as the\n$U(1)$ vector potential. In the case of $S^1$ domain-wall fermion on a\ntwo-dimensional flat lattice, we find a competition between the\nAharonov-Bohm(AB) effect and gravitational gap in the Dirac eigenvalue\nspectrum, which leads to anomaly of the time-reversal ($T$) symmetry. Our\nnumerical result shows a good consistency with the Atiyah-Patodi-Singer index\ntheorem on a disk inside the $S^1$ domain-wall, which describes the\ncancellation of the $T$ anomaly between the bulk and edge. When the $U(1)$ flux\nis squeezed inside one plaquette, and the AB phase takes a quantized value\n$\\pi$ mod $2\\pi\\mathbb{Z}$, the anomaly inflow drastically changes: the strong\nflux creates another domain-wall around the flux to make the two zero modes\ncoexist. This phenomenon is also observed in the $S^2$ domain-wall fermion in\nthe presence of a magnetic monopole. We find that the domain-wall creation\naround the monopole microscopically explains the Witten effect.",
        "positive": "Screening at finite temperature and density: We present lattice QCD results on heavy quark free energies, extract from its\ntemperature dependence entropy and internal energy contributions, and discuss\nthe onset of medium effects that lead to screening of static quark-antiquark\nsources in a thermal medium. Most results are obtained in (2+1)-flavour QCD on\na line of constant physics with almost realistic quark masses and compared to\nprevious results from 2-flavor QCD as well as pure gauge theory. Furthermore,\nwe discuss results on the density dependence of screening masses that have been\nobtained using a leading order Taylor expansion in the baryon chemical\npotential."
    },
    {
        "anchor": "Light Hadron Spectroscopy with Two Flavors of Dynamical Quarks on the\n  Lattice: We present results of a numerical calculation of lattice QCD with two\ndegenerate flavors of dynamical quarks, identified with up and down quarks, and\nwith a strange quark treated in the quenched approximation. The lattice action\nand simulation parameters are chosen with a view to carrying out an\nextrapolation to the continuum limit as well as chiral extrapolations. Gauge\nconfigurations are generated with a renormalization-group improved gauge action\nand a mean field improved clover quark action at three values of $\\beta$ and\nfour sea quark masses. The sizes of lattice are chosen so that the physical\nspatial size is kept constant. Hadron masses, light quark masses and meson\ndecay constants are measured at five valence quark masses. We also carry out\ncomplementary quenched simulations with the same improved actions. The quenched\nspectrum from this analysis agrees well in the continuum limit with the one of\nour earlier work using the standard action. We find the two-flavor full QCD\nmeson masses in the continuum limit to be much closer to experimental meson\nmasses than those from quenched QCD. We take these results as manifestations of\nsea quark effects in two-flavor full QCD. For baryon masses full QCD values for\nstrange baryons are in agreement with experiment, while they differ\nincreasingly with decreasing strange quark content, resulting in a nucleon mass\nhigher than experiment. The pattern suggests finite size effects as a possible\norigin for this deviation. For light quark masses in the continuum limit we\nobtain values which are reduced by about 25% compared to the values in quenched\nQCD. We also present results for decay constants where large scaling violations\nobstruct a continuum extrapolation. Need for a non-perturbative estimate of\nrenormalization factors is discussed.",
        "positive": "Spectrum of closed k-strings in D=2+1: We calculate the excitation spectrumof closed k-strings in 2+1 dimensional\nSU(N) gauge theories for N = 4, 5 and k = 2. Our results demonstrate that the\nlow-lying spectrum of the k = 2 string falls into sectors that belong to nearly\npure antisymmetric and symmetric representations, showing that k-strings know\nnot only about the centre of the group, but also about the full group. We also\nobserve that the lightest states in each irreducible representation are\nconsistent with what one would expect from an effective string theory that\nbelongs to the same bosonic universality class (Nambu-Goto) as the fundamental\nstring. We find that the corrections compared to the free string theory are of\nO(1), in striking contrast to the very small correction observed for the\nfundamental string. We also observe unbound w = 2 states."
    },
    {
        "anchor": "Extracting Scattering Phase-Shifts in Higher Partial-Waves from Lattice\n  QCD Calculations: L\\\"uscher's method is routinely used to determine meson-meson, meson-baryon\nand baryon-baryon s-wave scattering amplitudes below inelastic thresholds from\nLattice QCD calculations - presently at unphysical light-quark masses. In this\nwork we review the formalism and develop the requisite expressions to extract\nphase-shifts describing meson-meson scattering in partial-waves with\nangular-momentum l<=6 and l=9. The implications of the underlying cubic\nsymmetry, and strategies for extracting the phase-shifts from Lattice QCD\ncalculations, are presented, along with a discussion of the signal-to-noise\nproblem that afflicts the higher partial-waves.",
        "positive": "The pole structure of the Lambda(1405) in a recent QCD simulation: The $\\Lambda(1405)$ baryon is difficult to detect in experiment, absent in\nmany quark model calculations, and supposedly manifested through a two-pole\nstructure. Its uncommon properties made it subject to numerous experimental and\ntheoretical studies in recent years. Lattice-QCD eigenvalues for different\nquark masses were recently reported by the Adelaide group. We compare these\neigenvalues to predictions of a model based on Unitary Chiral Perturbation\nTheory. The UCHPT calculation predicts the quark mass dependence remarkably\nwell. It also explains the overlap pattern with different meson-baryon\ncomponents, mainly $\\pi\\Sigma$ and $\\bar KN$, at different quark masses. More\naccurate lattice QCD data are required to draw definite conclusions on the\nnature of the $\\Lambda(1405)$."
    },
    {
        "anchor": "Gluon propagators in the deep IR region and non-Abelian dual\n  superconductivity for SU(3) Yang-Mills: We have presented non-Abelian dual superconductivity picture in the SU(3)\nYang-Mills(YM) theory, and shown evidences such as the restricted U(2)-field\ndominance and the non-Abelian magnetic monopole dominance in the string\ntension. To establish the dual superconductivity picture, the dual Meissner\neffect in Yang-Mills theory must be examined, and we also presented the\nevidence of non-Abelian dual Meissner effect by measuring chromo-electric flux\ntube in the last lattice conferences.\n  In this talk, by applying a new formulation of the YM theory on a lattice,\nthe we further investigate the non-Abelian dual Meissner effect for SU(3) YM\ntheory through correlation function. We examine non-abelian magnetic monopole\ncurrents as well as color flux created by the quark-antiquark source.",
        "positive": "Non-perturbative determination of the $\u039b$-parameter in the pure\n  SU(3) gauge theory from the twisted gradient flow coupling: We evaluate the $\\Lambda$-parameter in the $\\overline{\\mathrm{MS}}$ scheme\nfor the pure SU(3) gauge theory with the twisted gradient flow (TGF) method. A\nrunning coupling constant $g_{\\mathrm{TGF}}^2(1/L)$ is defined in a finite\nvolume box with size of $L^4$ with the twisted boundary condition. This defines\nthe TGF scheme. Using the step scaling method for the TGF coupling with lattice\nsimulations, we can evaluate the $\\Lambda$-parameter non-perturbatively in the\nTGF scheme. In this paper we determine the dimensionless ratios,\n$\\Lambda_{\\mathrm{TGF}}/\\sqrt{\\sigma}$ and $r_{0}\\Lambda_{\\mathrm{TGF}}$\ntogether with the $\\Lambda$-parameter ratio\n$\\Lambda_{\\mathrm{SF}}/\\Lambda_{\\mathrm{TGF}}$ on the lattices numerically.\nCombined with the known ratio\n$\\Lambda_{\\overline{\\mathrm{MS}}}/\\Lambda_{\\mathrm{SF}}$, we obtain\n$\\Lambda_{\\overline{\\mathrm{MS}}}/\\sqrt{\\sigma} = 0.517(10)(^{+8}_{-7})$ and\n$r_{0}\\Lambda_{\\overline{\\mathrm{MS}}}=0.593(12)(^{+12}_{-9})$, where the first\nerror is statistical one and the second is our estimate of systematic\nuncertainty."
    },
    {
        "anchor": "Critical behavior and continuum scaling of $3D$ $Z(N)$ lattice gauge\n  theories: Three-dimensional $Z(N)$ lattice gauge theories are studied numerically at\nfinite temperature for $N$ = 5, 6, 8, 12, 13, 20 and for $N_t$=2,4,8. For each\nmodel the location of phase transitions and its critical indices are\ndetermined. The scaling of critical points with $N$ is proposed. The data\nobtained enable us to verify the scaling near the continuum limit for the\n$Z(N)$ models at finite temperatures.",
        "positive": "On the phase diagram and the singlet scalar channel in Yang-Mills-Higgs\n  theory: Yang-Mills-Higgs theory is quite a remarkable theory in that it shows very\ndifferent behaviors without phase transitions. It is dominated by the\nBrout-Englert-Higgs mechanism in some domain of the phase diagram, while it is\nessentially QCD-like in another. It is expected that albeit there is no\nqualitative difference, there are substantially quantitative differences\nthroughout the spectrum. This is investigated using lattice theory for the case\nof the scalar singlet channel for more than a hundred different points in the\nphase diagram. It is found that the results deviate partly substantially from\nthe expectations in some cases, but in others justify the picture of a weakly\ninteracting theory - even in cases of rather strong interactions at the\nultraviolet cutoff."
    },
    {
        "anchor": "Critical Exponent for the Density of Percolating Flux: This paper is a study of some of the critical properties of a simple model\nfor flux. The model is motivated by gauge theory and is equivalent to the Ising\nmodel in three dimensions. The phase with condensed flux is studied. This is\nthe ordered phase of the Ising model and the high temperature, deconfined phase\nof the gauge theory. The flux picture will be used in this phase. Near the\ntransition, the density is low enough so that flux variables remain useful.\nThere is a finite density of finite flux clusters on both sides of the phase\ntransition. In the deconfined phase, there is also an infinite, percolating\nnetwork of flux with a density that vanishes as $T \\rightarrow T_{c}^{+}$. On\nboth sides of the critical point, the nonanalyticity in the total flux density\nis characterized by the exponent $(1-\\alpha)$. The main result of this paper is\na calculation of the critical exponent for the percolating network. The\nexponent for the density of the percolating cluster is $ \\zeta = (1-\\alpha) -\n(\\varphi-1)$. The specific heat exponent $\\alpha$ and the crossover exponent\n$\\varphi$ can be computed in the $\\epsilon$-expansion. Since $\\zeta <\n(1-\\alpha)$, the variation in the separate densities is much more rapid than\nthat of the total. Flux is moving from the infinite cluster to the finite\nclusters much more rapidly than the total density is decreasing.",
        "positive": "Massive Overlap Fermions on Anisotropic Lattices: We formulate the massive overlap fermions on anisotropic lattices.\n  We find that the dispersion relation for the overlap fermion resembles the\ncontinuum form in the low-momentum region once the bare parameters are properly\ntuned. The quark self-energy and the quark field renormalization constants are\ncalculated to one-loop in bare lattice perturbation theory.\n  We argue that massive domain wall quarks might be helpful in lattice QCD\nstudies on heavy-light hadron spectroscopy."
    },
    {
        "anchor": "BK-parameter from Nf = 2 twisted mass lattice QCD: We present an unquenched $N_f=2$ lattice computation of the $B_{K}$ parameter\nwhich controls $K^0-\\bar K^0$ oscillations. A partially quenched setup is\nemployed with two maximally twisted dynamical (sea) light Wilson quarks, and\nvalence quarks of both the maximally twisted and the Osterwalder--Seiler\nvariety. Suitable combinations of these two kinds of valence quarks lead to a\nlattice definition of the $B_{K}$ parameter which is both multiplicatively\nrenormalizable and O($a$) improved. Employing the non-perturbative RI-MOM\nscheme, in the continuum limit and at the physical value of the pion mass we\nget $B^{\\rm RGI}_K=0.729\\pm 0.030$, a number well in line with the existing\nquenched and unquenched determinations.",
        "positive": "Critical Behavior of CP^1 at theta = pi, Haldane's Conjecture and the\n  Universality Class: Using an approach to analyze the theta dependence of systems with a\ntheta-term we recently proposed, the critical behavior of CP^1 at theta=pi is\nstudied. We find a region outside the strong coupling regime where Haldane's\nconjecture is verified. The critical line however does not belong to the\nuniversality class of the Wess-Zumino-Novikov-Witten model at topological\ncoupling k=1 since it shows continuously varying critical exponents."
    },
    {
        "anchor": "Euclidean Quantum Field Theory from Variational Dynamics: A variational phase space is constructed for a system of fields on Euclidean\nspace with periodic boundary conditions. An extended action functional is\ndefined such that the Euler-Lagrange equations generate a symplectic flow on\nthe variational phase space. This symplectic flow is numerically integrated as\nit evolves with respect to the variational parameter. Assuming ergodicity, the\nresulting flow samples the Euclidean path integral.",
        "positive": "Monte-Carlo simulation of the chiral Gross-Neveu model: We investigate the two flavor chiral Gross-Neveu model in the Schroedinger\nfunctional on the lattice. The procedure necessary to recover chiral symmetry\nin the continuum limit of this model with Wilson fermions is discussed. We\nintroduce several useful observables and present a first demonstration of the\nfeasibility of Monte-Carlo simulations in this model."
    },
    {
        "anchor": "Quark distribution inside a pion in many-flavor (2 + 1)-dimensional QCD\n  using lattice computations: UV listens to IR: We study the changes in the short-distance quark structure of the\nNambu-Goldstone boson when the long-distance symmetry-breaking scales are\ndepleted controllably. We achieve this by studying the valence Parton\nDistribution Function (PDF) of pion in 2+1 dimensional two-color QCD, with the\nnumber $N$ of massless quarks as the tunable parameter that slides the theory\nfrom being strongly broken for $N=0$ to the conformal window for $N>4$, where\nthe theory is gapped by the fixed finite volume. We perform our study\nnon-perturbatively using lattice simulations with $N=0,2,4,8$ flavors of nearly\nmassless two-component Wilson-Dirac sea quarks and employ the leading-twist\nformalism (LaMET/SDF) to compute the PDF of pion at a fixed valence mass. We\nfind that the relative variations in the first few PDF moments are only mild\ncompared to the changes in decay constant, but the shape of the reconstructed\n$x$-dependent PDF itself dramatically changes from being broad in the\nscale-broken sector to being sharply peaked in the near-conformal region, best\nreflected in PDF shape observables such as the cumulants.",
        "positive": "Pion couplings to the scalar B meson: We present two-flavor lattice QCD estimates of the hadronic couplings\n$g_{B^*_0 B \\pi}$ and $g_{B_1^* B_0^* \\pi}$ that parametrise the non leptonic\ndecays $B^*_0 \\to B \\pi$ and $B^*_1 \\to B_0^* \\pi$. We use CLS two-flavour\ngauge ensembles. Our framework is the Heavy Quark Effective Theory (HQET) in\nthe static limit and solving a Generalized Eigenvalue Problem (GEVP) reveals\ncrucial to disentangle the $B^*_0$($B^*_1$) state from the $B \\pi$($B^*\\pi$)\nstate. This work brings us some experience on how to treat the possible\ncontribution from multihadronic states to correlation functions calculated on\nthe lattice, especially when $S$-wave states are involved."
    },
    {
        "anchor": "Chiral Symmetry and Lattice Fermions: The subject of these summer school lectures are (i) Chiral symmetry; (ii)\nAnomalies; (iii) Domain wall fermions; (iv) Overlap fermions and the\nGinsparg-Wilson equation",
        "positive": "On a first order transition in QCD with up, down and strange quarks: We consider the quark-mass dependence of the baryon octet and decuplet ground\nstate masses. It is predicted that QCD dynamics implies a first order\ntransition when increasing the strange quark mass from its chiral limit towards\nits physical value. Our claim relies on a global fit to the available QCD\nlattice data on such baryon masses. Quantitative results based on an\napplication of the chiral SU(3) Lagrangian at N$^3$LO are discussed. We predict\nan anomalous sector of QCD where stable baryonic matter would be composed of\nlambda or anti-lambda particles rather than nucleons and anti-nucleons."
    },
    {
        "anchor": "A critical comparison of different definitions of topological charge on\n  the lattice: A detailed comparison is made between the field-theoretic and geometric\ndefinitions of topological charge density on the lattice. Their\nrenormalizations with respect to continuum are analysed. The definition of the\ntopological susceptibility, as used in chiral Ward identities, is reviewed.\nAfter performing the subtractions required by it, the different lattice methods\nyield results in agreement with each other. The methods based on cooling and on\ncounting fermionic zero modes are also discussed.",
        "positive": "Stout Smearing for Twisted Mass Fermions: The effect of Stout smearing is investigated in numerical simulations with\ntwisted mass Wilson quarks. The phase transition near zero quark mass is\nstudied on 12^3x24, 16^3x32 and 24^3x48 lattices at lattice spacings a = 0.1 -\n0.125 fm."
    },
    {
        "anchor": "Interplay between sign problem and Z_3 symmetry in three-dimensional\n  Potts model: We construct four kinds of Z3-symmetric three-dimentional (3-d) Potts models,\neach with different number of states at each site on a 3-d lattice, by\nextending the 3-d three-state Potts model. Comparing the ordinary Potts model\nwith the four Z3-symmetric Potts models, we investigate how Z3 symmetry affects\nthe sign problem and see how the deconfinement transition line changes in the\n$\\mu-\\kappa$ plane as the number of states increases, where $\\mu$ $(\\kappa)$\nplays a role of chemical potential (temperature) in the models. We find that\nthe sign problem is almost cured by imposing Z3 symmetry. This mechanism may\nhappen in Z3-symmetric QCD-like theory. We also show that the deconfinement\ntransition line has stronger $\\mu$-dependence with respect to increasing the\nnumber of states.",
        "positive": "Search for Efficient Formulations for Hamiltonian Simulation of\n  non-Abelian Lattice Gauge Theories: Hamiltonian formulation of lattice gauge theories (LGTs) is the most natural\nframework for the purpose of quantum simulation, an area of research that is\ngrowing with advances in quantum-computing algorithms and hardware. It,\ntherefore, remains an important task to identify the most accurate, while\ncomputationally economic, Hamiltonian formulation(s) in such theories,\nconsidering the necessary truncation imposed on the Hilbert space of gauge\nbosons with any finite computing resources. This paper is a first step toward\naddressing this question in the case of non-Abelian LGTs, which further require\nthe imposition of non-Abelian Gauss's laws on the Hilbert space, introducing\nadditional computational complexity. Focusing on the case of SU(2) LGT in 1+1 D\ncoupled to matter, a number of different formulations of the original\nKogut-Susskind framework are analyzed with regard to the dependence of the\ndimension of the physical Hilbert space on boundary conditions, system's size,\nand the cutoff on the excitations of gauge bosons. The impact of such\ndependencies on the accuracy of the spectrum and dynamics is examined, and the\n(classical) computational-resource requirements given these considerations are\nstudied. Besides the well-known angular-momentum formulation of the theory, the\ncases of purely fermionic and purely bosonic formulations (with open boundary\nconditions), and the Loop-String-Hadron formulation are analyzed, along with a\nbrief discussion of a Quantum Link Model of the same theory. Clear advantages\nare found in working with the Loop-String-Hadron framework which implements\nnon-Abelian Gauss's laws a priori using a complete set of gauge-invariant\noperators. Although small lattices are studied in the numerical analysis of\nthis work, and only the simplest algorithms are considered, a range of\nconclusions will be applicable to larger systems and potentially to higher\ndimensions."
    },
    {
        "anchor": "The Static Potential with Hypercubic Blocking: We measure the static potential from Wilson loops constructed using\nhypercubic blocked (HYP) links. The HYP potential agrees with the potential\nmeasured using thin links for distances r/a>=2. We calculated the lowest order\nperturbative expansion of the lattice Coulomb potential of HYP links. These\nresults are used in analyzing the static potential both on quenched and\ndynamical lattices. The statistical accuracy of the potential with HYP links\nimproves by about an order of magnitude, giving a reliable scale even with\nlimited statistics both on quenched and dynamical lattices.",
        "positive": "Comparison of Chiral Fermion Methods: We present a comparison of various five-dimensional representations of chiral\nfermions considering their cost and residual chiral symmetry breaking."
    },
    {
        "anchor": "First Study for the Pentaquark Potential in SU(3) Lattice QCD: The static penta-quark (5Q) potential $V_{\\rm 5Q}$ is studied in SU(3)\nlattice QCD with $16^3\\times 32$ and $\\beta$=6.0 at the quenched level. From\nthe 5Q Wilson loop, $V_{\\rm 5Q}$ is calculated in a gauge-invariant manner,\nwith the smearing method to enhance the ground-state component. $V_{\\rm 5Q}$ is\nwell described by the OGE plus multi-Y Ansatz: a sum of the OGE Coulomb term\nand the multi-Y-type linear term proportional to the minimal total length of\nthe flux-tube linking the five quarks. Comparing with ${\\rm Q \\bar Q}$ and 3Q\npotentials, we find a universality of the string tension, $\\sigma_{\\rm Q \\bar\nQ} \\simeq \\sigma_{\\rm 3Q} \\simeq \\sigma_{\\rm 5Q}$, and the OGE result for\nCoulomb coefficients.",
        "positive": "Chiral phase transition of three flavor QCD with nonzero magnetic field\n  using standard staggered fermions: Lattice simulations for (2+1)-flavor QCD with external magnetic field\ndemonstrated that the quark mass is one of the important parameters responsible\nfor the (inverse) magnetic catalysis. We discuss the dependences of chiral\ncondensates and susceptibilities, the Polyakov loop on the magnetic field and\nquark mass in three degenerate flavor QCD. The lattice simulations are\nperformed using standard staggered fermions and the plaquette action with\nspatial sizes Ns = 16 and 24 and a fixed temporal size Nt = 4. The value of the\nquark masses are chosen such that the system undergoes a first order chiral\nphase transition and crossover with zero magnetic field. We find that in light\nmass regime, the quark chiral condensate undergoes magnetic catalysis in the\nwhole temperature region and the phase transition tend to become stronger as\nthe magnetic field increases. In crossover regime, deconfinement transition\ntemperature is shifted by the magnetic field when quark mass ma is less than\n0.4. The lattice cutoff effects are also discussed."
    },
    {
        "anchor": "Instantons, the QCD Vacuum, and Hadronic Physics: A large body of evidence from lattice calculations indicates that instantons\nplay a major role in the physics of light hadrons. This evidence is summarized,\nand recent results concerning the instanton content of the SU(3) vacuum,\ninstanton contributions to the static potential, and a new class of instanton\nsolutions at finite temperature are reviewed.",
        "positive": "QED corrections to leptonic decay rates: RBC/UKQCD is preparing a calculation of leptonic decay rates including\nisospin breaking corrections using a perturbative approach to include NLO\ncontributions from QED effects. We present preliminary numerical results for a\ncontribution to the leptonic pion decay rate and report on exploratory studies\nof computational techniques based on all-to-all propagators."
    },
    {
        "anchor": "Systematic study of operator dependence in nucleus calculation at large\n  quark mass: Recently it is claimed that there is a significant systematic error from\nexcited state contributions in the nucleus correlation functions by comparing\nwith calculations using the exponential and wall source operators. However, the\nwall source result is obtained in much earlier time than the plateau region. In\norder to investigate the systematic error in the plateau region, we calculate\nthe correlation functions with both the operators in quenched QCD at 0.8 GeV\npion mass and in $N_f=2+1$ QCD at 0.7 GeV pion mass in high accuracy. In this\nreport we present preliminary results of those calculations, and show that the\nenergy shift obtained from the two sources agree with each other, if those are\ndetermined from a region, where both the nucleon and two-nucleon correlation\nfunctions have plateaus.",
        "positive": "The Gross-Neveu model and QCDs chiral phase transition: Quantum chromodynamics has a rather complicated phase structure. The finite\ntemperature, chiral phase structure depends on the number of flavours and to a\nlarge extent on the particular values of the fermion masses. For two massless\nflavours there is a true second order transition. It has been argued that this\ntransition belongs to the universality class of the three-dimensional O(4) spin\nmodel. The arguments have been questioned recently, and the transition was\nclaimed to be mean field behaved. In this lecture we discuss this issue at the\nexample of the three-dimensional, parity symmetric Gross-Neveu model at finite\ntemperature, with a large number N of fermions. At zero temperature there is a\nphase where parity is spontaneously broken. At finite temperature, this model\nhas a parity restoring second order transition. It reveals considerable\nsimilarity to the QCD chiral phase transition. There are related questions here\nconcerning the universality class. We solve this problem essentially by means\nof the following methods: Large N expansion, dimensional reduction in the\nframework of quantum field theory, and high order convergent series expansions\nabout disordered lattice systems."
    },
    {
        "anchor": "Non-relativistic spectrum of two-color QCD at non-zero baryon density: The heavy quarkonium spectrum of Two Color QCD (QC$_2$D) at non-zero quark\nchemical potential $\\mu$ and temperature $T$ with $\\mu/T\\gg1$ has been\ncalculated in both $S$- and $P$-wave channels using a lattice non-relativistic\nformulation of QC$_2$D. As $\\mu$ is varied, the quarkonium spectra reveal three\nseparate regions, corroborating previous findings that there are three distinct\nphysical regimes of QC$_2$D at low temperature and high baryon density:\nhadronic matter, quark/quarkyonic matter, and deconfined matter. The results\nare interpreted in terms of the formation of heavy-light $Qq$ states in the\ntwo-color baryonic medium.",
        "positive": "Multigrid Monte Carlo with higher cycles in the Sine Gordon model: We study the dynamical critical behavior of multigrid Monte Carlo for the two\ndimensional Sine Gordon model on lattices up to 128 x 128. Using piecewise\nconstant interpolation, we perform a W-cycle (gamma=2). We examine whether one\ncan reduce critical slowing down caused by decreasing acceptance rates on large\nblocks by doing more work on coarser lattices. To this end, we choose a higher\ncycle with gamma = 4. The results clearly demonstrate that critical slowing\ndown is not reduced in either case."
    },
    {
        "anchor": "A New Order Parameter for the Higgs Transition in $SU(2)$-Higgs Theory: We investigate the Higgs transition within the four dimensional $SU(2)-$\ngauge-Higgs model in search for an order parameter as a function of the Higgs\nfield hopping parameter, $\\kappa$, using Lattice technique. We measure the\nHiggs condensate after applying Landau Gauge Fixing and study the corresponding\nsusceptibility, magnetization and fourth order Binder cumulant using four\ndifferent spatial volumes with $N_\\tau =2$. The computation is carried out with\ngauge coupling, $\\beta_g = 8$, for a range of scalar self-coupling, $\\lambda =\n\\{0.00010, 0.00350\\}$, with emphasis near the critical end-point. Finite size\nscaling analysis of the gauge fixed condensate and its cumulants agree with the\nstandard $3$d Ising values $\\nu=0.62997$, $\\beta/\\nu=0.518$, $\\gamma/\\nu=1.964$\nat $\\lambda = 0.00150$. These results are in agreement with previous studies\nsuggesting $3$d Ising universality class. The numerical results also indicate\nthat, at the transition point, the gauge fixed condensate vanishes in the\ninfinite volume limit.",
        "positive": "Thermodynamic Lattice Study for Preconformal Dynamics in Strongly\n  Flavored Gauge Theory: By using the lattice Monte-Carlo simulation, we investigate the finite\ntemperature (T) chiral phase transition at color SU(3) gauge theories with\nvarious species of fundamental fermions, and discuss the signal of the\n(pre-)conformality at large Nf (num. of flavors.) via their comparisons. As Nf\nincreases, we observe stronger fermion screening effects which result from a\nlarger fermion multiplicity. We investigate a finite T step-scaling associated\nwith a uniqueness of the critical temperature (Tc) at each Nf, then the\nvanishing step-scaling indicates the emergence of the conformality around Nf* =\n10 - 12. Further, motivated by the functional renormalization group analyses,\nwe examine the Nf dependence of Tc, whose vanishing behavior indicates the\nonset of conformal window around Nf* = 9 - 10."
    },
    {
        "anchor": "Mass splittings and matrix elements of mesons and baryons containing a\n  single heavy quark: We present a study in the quenched approximation of the $B$ parameter $B_B$\nand the decay constant $f_B$ using heavy-quark propagators implemented in the\nstatic approximation, and light-quark propagators computed using an\n$O(a)$-improved fermion action. We find a value of $\\Bbstat$ close unity, and\ndiscuss the systematic errors entering into the calculation. $\\fbstat$ is\nextracted using a variational fitting technique in order to obtain a reliable\nestimate of the ground state.\n  In the second part of the talk, we describe an exploratory study of baryons\ncontaining a single heavy quark, computed using the $O(a)$-improved fermion\naction. We obtain masses generally in good agreement with experiment in both\nthe charm and beauty sectors. We also report preliminary results for the form\nfactor $G_1$ in the semi-leptonic $\\Lambda_b \\rightarrow \\Lambda_c$ transition.",
        "positive": "Non-commutative Differential Calculus and the Axial Anomaly in Abelian\n  Lattice Gauge Theories: The axial anomaly in lattice gauge theories has a topological nature when the\nDirac operator satisfies the Ginsparg-Wilson relation. We study the axial\nanomaly in Abelian gauge theories on an infinite hypercubic lattice by\nutilizing cohomological arguments. The crucial tool in our approach is the\nnon-commutative differential calculus~(NCDC) which makes the Leibniz rule of\nexterior derivatives valid on the lattice. The topological nature of the\n``Chern character'' on the lattice becomes manifest in the context of NCDC. Our\nresult provides an algebraic proof of L\\\"uscher's theorem for a\nfour-dimensional lattice and its generalization to arbitrary dimensions."
    },
    {
        "anchor": "Local Polyakov-loop fluctuation and center domains in quark-gluon plasma\n  with many colors: The deconfinement transition in non-Abelian gauge theory is understood as\nspontaneous breaking of $\\mathbb{Z}_N$ symmetry at high temperatures.\nAccordingly, quark-gluon plasma generally includes some partial cells called\ncenter domains, each with a homogeneous Polyakov-loop expectation value. In\nthis work, constructing an effective action describing the deconfinement vacuum\nof Yang-Mills theory with $N$ colors, we discuss the properties of center\ndomains. First, we evaluate the spatial correlation of local Polyakov-loop\nfluctuation and demonstrate that some fluctuation becomes a\nNambu-Goldstone-like mode in the large-$N$ limit. We also discuss surface\ntension between two $\\mathbb{Z}_N$ center domains. Second, we estimate the\nglobal vacuum-to-vacuum transition in a single center domain. We find that some\nthreshold volume exists, where a domain larger than this volume is stable, and\nvice versa. Identifying the threshold as the lower bound of a stable center\ndomain volume, we quantitatively argue the typical volume scale of center\ndomains.",
        "positive": "Phase diagram of d=4 Ising Model with two couplings: We study the phase diagram of the four dimensional Ising model with first and\nsecond neighbour couplings, specially in the antiferromagnetic region, by using\nMean Field and Monte Carlo methods. From the later, all the transition lines\nseem to be first order except that between ferromagnetic and disordered phases\nin a region including the first-neighbour Ising transition point."
    },
    {
        "anchor": "Longitudinal and transverse meson correlators in the deconfined phase\n  from the lattice: It has long been known that QCD undergoes a deconfining phase transition at\nhigh temperature. One of the consequent features of this new, quark-gluon phase\nis that hadrons become unbounded. In this talk meson correlation functions at\nnon-zero momentum are studied in the deconfined phase using the Maximum Entropy\nMethod.",
        "positive": "Adjoint chromoelectric and -magnetic correlators with gradient flow: When QCD is described by a nonrelativistic effective field theory, operators\nconsisting of gluonic correlators of two chromoelectric or -magnetic fields\nwill often appear in descriptions of quarkonium physics. At zero T, these\ncorrelators give the masses of gluelumps and the moments of these correlators\ncan be used to understand the inclusive P-wave decay of quarkonium. At finite T\nthese correlators define the diffusion of the heavy quarkonium. However, these\ncorrelators come with a divergent term in lattice spacing which needs to be\ntaken care of. We inspect these correlators in pure gauge theory with gradient\nflow smearing, which should allow us to reduce and remove the divergence more\ncarefully. In these proceedings, we focus on the effect of gradient flow to\nthese correlators and the reduction of this divergence."
    },
    {
        "anchor": "Three Topics in Renormalization and Improvement: This is an expanded version of lecture notes, delivered at the XCIII Les\nHouches Summer School (August 2009). Our aim is to present three very specific\ntopics: (i) The consequences of the loss of chiral symmetry in the Wilson\nlattice regularization of the fermionic action and its recovery in the\ncontinuum limit. The treatment of these arguments involves lattice Ward\nidentities. (ii) The definition and properties of mass independent\nrenormalization schemes, which are suitable for a non-perturbative computation\nof various operator renormalization constants. (iii) The modification of the\nWilson fermion action, by the introduction of a chirally twisted mass term\n(known as twisted mass QCD - tmQCD), which results to improved\n(re)normalization and scaling properties for physical quantities of interest.",
        "positive": "Finite temperature QCD with physical $(u/d, s, c)$ domain-wall quarks: In order to understand the role of QCD in the early universe, we perform\nhybrid Monte-Carlo simulation of lattice QCD with $N_f=2+1+1$ optimal\ndomain-wall quarks at the physical point, on the $64^3 \\times\n(6,8,10,12,16,20,64)$ lattices, each with three lattice spacings. The lattice\nspacings and the bare quark masses are determined on the $64^4$ lattices. The\nresulting gauge ensembles provide a basis for studying finite temperature QCD\nwith $N_f=2+1+1 $ domain-wall quarks at the physical point. In this Proceeding,\nwe present our first result on the topological susceptibility of the QCD\nvacuum. The topological charge of each gauge configuration is measured by the\nclover charge in the Wilson flow at the same flow time in physical units, and\nthe topological susceptibility $ \\chi_t(a,T) $ is determined for each ensemble\nwith lattice spacing $a$ and temperature $T$. Using the topological\nsusceptibility $\\chi_t(a,T) $ of 15 gauge ensembles with three lattice spacings\nand different temperatures in the range $T \\sim 155-516 $~MeV, we extract the\ntopological susceptibility $\\chi_t(T)$ in the continuum limit."
    },
    {
        "anchor": "QCD Level Density from Maximum Entropy Method: We propose a method to calculate the QCD level density directly from the\nthermodynamic quantities obtained by lattice QCD simulations with the use of\nthe maximum entropy method (MEM). Understanding QCD thermodynamics from QCD\nspectral properties has its own importance. Also it has a close connection to\nphenomenological analyses of the lattice data as well as experimental data on\nthe basis of hadronic resonances. Our feasibility study shows that the MEM can\nprovide a useful tool to study QCD level density.",
        "positive": "Colour confinement and dual superconductivity of the vacuum - I: We study dual superconductivity of the ground state of SU(2) gauge theory, in\nconnection with confinement. We do that measuring on the lattice a disorder\nparameter describing condensation of monopoles. Confinement appears as a\ntransition to dual superconductor, independent of the abelian projection\ndefining monopoles. Some speculations are made on the existence of a more\nappropriate disorder parameter. A similar study for SU(3) is presented in a\ncompanion paper."
    },
    {
        "anchor": "A Fluctuation Theory of Topological Susceptibility: We investigate the long-range statistical correlations, whereby discuss the\nnature of the undermining interacting/ noninteracting domains and associated\nphase transitions under variations of the quark mass and the mass scale that\ncorresponds to renormalized pion masses and the dimensions of an ensemble of\nslab sub-volumes of an arbitrary simulated lattice. The purpose of this paper\nis to compute the system's stability and its phase structures when it's model\nparameters vary infinitesimally. In particular, we focus on the stability\nproperties and phases of an arbitrary (2+1) flavor QCD configuration under\nfluctuations of its parameters. In order to investigate the nature of\nstatistical and systematic errors, and the presence of noises in the system, we\nexplore fluctuation theory equivalences of the slab sub-volume method of\ncomputing the topological susceptibility with its low energy ChPT counterpart.\nHereby, we find that the ChPT configurations always correspond to a\nnon-interacting statistical basis in the space of the quark mass and the mass\nscale that corresponds to renormalized pion masses. The second system as an\nensemble of finite slab sub-volumes of a simulated lattice turns out to be\ngenerically interacting under fluctuations of the slab dimensions. However, it\nyields an ill-defined degenerate system in the infinitesimal limit of slab\nparameters. It is worth mentioning that implications of the intrinsic geometric\nanalysis are well suited towards the modeling based understanding of the\ngluonic topological charge density fluctuations, quark mass dependence and long\nauto-correlation of the global topology. Finally, we discuss the stability\nproperties of sub-volume simulated lattice improvements towards the\nunderstanding of QCD vacua, the behavior of UV divergences, finite-volume\neffects, statistical precision, simultaneous measurements, and associated\nquantum channel measurements.",
        "positive": "Simulating the Electroweak Phase Transition in the SU(2) Higgs Model: Numerical simulations are performed to study the finite temperature phase\ntransition in the SU(2) Higgs model on the lattice. In the presently\ninvestigated range of the Higgs boson mass, below 50 GeV, the phase transition\nturns out to be of first order and its strength is rapidly decreasing with\nincreasing Higgs boson mass. In order to control the systematic errors, we also\nperform studies of scaling violations and of finite volume effects."
    },
    {
        "anchor": "Using infinite volume, continuum QED and lattice QCD for the hadronic\n  light-by-light contribution to the muon anomalous magnetic moment: In our previous work, the connected and leading disconnected hadronic\nlight-by-light contributions to the muon anomalous magnetic moment (g - 2) have\nbeen computed using lattice QCD ensembles corresponding to physical pion mass\ngenerated by the RBC/UKQCD collaboration. However, the calculation is expected\nto suffer from a significant finite volume error that scales like $1/L^2$ where\n$L$ is the spatial size of the lattice. In this paper, we demonstrate that this\nproblem is cured by treating the muon and photons in infinite volume, continuum\nQED, resulting in a weighting function that is pre-computed and saved with\naffordable cost and sufficient accuracy. We present numerical results for the\ncase when the quark loop is replaced by a muon loop, finding the expected\nexponential approach to the infinite volume limit and consistency with the\nknown analytic result. We have implemented an improved weighting function which\nreduces both discretization and finite volume effects arising from the hadronic\npart of the amplitude.",
        "positive": "More about vacuum structure of Linear Sigma Model: In the study of critical phenomena of QCD, a linear sigma model (LSM) is\noften analyzed as it shares many properties with QCD. Motivated by recent\narguments on effective restoration of the U_A(1) symmetry around the critical\ntemperature, the renormalization group flow of U(2)$\\otimes$U(2) LSM with a\nsmall violation of the U_A(1) symmetry is examined in the traditional epsilon\nexpansion in threedimensions. With a mass-dependent renormalization scheme, we\ninvestigate the attractive basin flowing into the O(4) LSM in the parameter\nspace and its dependence on the size of the U_A(1) breaking. Special emphasis\nis put on how the decoupling of the heavier degrees of freedom occur as\napproaching the O(4) LSM."
    },
    {
        "anchor": "An O(a) modified lattice set-up of the Schr\u00f6dinger functional in SU(3)\n  gauge theory: The set-up of the QCD Schr\\\"odinger functional (SF) on the lattice with\nstaggered quarks requires an even number of points $L/a$ in the spatial\ndirections, while the Euclidean time extent of the lattice, $T/a$, must be odd.\nIdentifying a unique renormalisation scale, $L=T$, is then only possible up to\nO($a$) lattice artefacts. In this article we study such lattices in the pure\nSU(3) gauge theory, where we can also compare to the standard set-up. We\nconsider the SF coupling as obtained from the variation of an SU(3) Abelian and\nspatially constant background field. The O($a$) lattice artefacts can be\ncancelled by the existing O($a$) boundary counterterm. However, its\ncoefficient, $\\ct$, differs at the tree-level from its standard value, so that\none first needs to re-determine the induced background gauge field. The\nperturbative one-loop correction to the coupling allows to determine $\\ct$ to\none-loop order. A few numerical simulations serve to demonstrate that residual\ncutoff effects in the step scaling function are small in both cases, $T=L\\pm a$\nand comparable to the standard case with $T=L$.",
        "positive": "Lattice QCD studies on baryon interactions from L\u00fcscher's finite\n  volume method and HAL QCD method: A comparative study between the L\\\"uscher's finite volume method and the\ntime-dependent HAL QCD method is given for the $\\Xi\\Xi$($^1\\mathrm{S}_0$)\ninteraction as an illustrative example. By employing the smeared source and the\nwall source for the interpolating operators, we show that the effective energy\nshifts $\\Delta E_{\\rm eff} (t)$ in L\\\"uscher's method do not agree between\ndifferent sources, yet both exhibit fake plateaux. On the other hand, the\ninteraction kernels $V(\\vec{r})$ obtained from the two sources in the HAL QCD\nmethod agree with each other already for modest values of $t$. We show that the\nenergy eigenvalues $\\Delta E(L)$ in finite lattice volumes ($L^3$) calculated\nby $V(\\vec{r})$ indicate that there is no bound state in the\n$\\Xi\\Xi(^1\\mathrm{S}_0)$ channel at $m_{\\pi}=0.51$ GeV in 2+1 flavor QCD."
    },
    {
        "anchor": "Perturbative Renormalisation for Low Moments of Generalised Parton\n  Distributions with Clover Fermions: We present the non-forward quark matrix elements of operators with one and\ntwo covariant derivatives needed for the renormalisation of the first and\nsecond moments of generalised parton distributions in one-loop lattice\nperturbation theory using clover fermions. For some representations of the\nhypercubic group commonly used in simulations we define the sets of possible\nmixing operators and compute the one-loop mixing matrices of renormalisation\nfactors. Tadpole improvement is applied to the results and some numerical\nexamples are presented.",
        "positive": "Nucleon Structure from Lattice QCD: We report results on the nucleon structure obtained from the lattice quantum\nchromodynamics calculation. These include the axial, electromagnetic, $\\pi NN$,\nand scalar form factors. The calculation is carried out at $\\beta = 6$ on a\n$16^3 \\times 24$ lattice with 24 quenched gauge configurations. The chiral\nlimit results are extrapolated from several light quark cases. For the\ndisconnected insertion (sea-quark contribution), we used the stochastic\nestimation with the $Z_2$ noise to calculate the diagonal and off-diagonal\ntraces of the inverse matrices with a size of $10^6 \\times 10^6$. It is found\nthat the $Z_2$ noise is the optimal choice and its comparison with the Gaussian\nnoise for our quark matrix is given. For the sea-quark contribution, we report\nresults on the strange condensate in the nucleon and the $\\pi N \\sigma$ term."
    },
    {
        "anchor": "The moment $\\langle x\\rangle_{u-d}$ of the nucleon from $N_f=2$ lattice\n  QCD down to nearly physical quark masses: We present an update of our analysis [1] which includes additional ensembles\nat different quark masses, lattice spacings and volumes, all with high\nstatistics. We use $N_f=2$ mass-degenerate quark flavours, employing the\nnon-perturbatively improved clover action. The lattice matrix elements are\nconverted to the $\\overline{\\rm MS}$ scheme via renormalization factors\ndetermined non-perturbatively in the RI$^\\prime$-MOM scheme. We have\nsystematically investigated excited state contributions, in particular, at the\nsmallest, near physical, pion mass. While our results~(with much increased\nprecision) are consistent with Ref.~[1], comparing with previous determinations\nwe find that excited state contributions can be significant if the quark\nsmearing is not suitably optimized, in agreement with other recent studies. The\ndifference with respect to the value for $\\langle x\\rangle_{u-d}$ extracted\nfrom experimental data is reduced but not resolved. Using lattice sizes in the\nrange $L m_\\pi\\sim 3.4-6.7$, no significant finite volume effects were\nobserved. Performing a controlled continuum limit that may remove the\ndiscrepancy will require simulations at lattice spacings $a< 0.06$ fm.",
        "positive": "Abelian Higgs model with charge conjugate boundary conditions: The abelian Higgs model is studied on the lattice with charge conjugate\nboundary conditions. A locally gauge invariant operator for the charged scalar\nfield is constructed and the charged scalar particle mass is calculated in the\nCoulomb phase of the lattice model. Agreement is found with the mass calculated\nin Coulomb gauge. The gauge invariant scalar field operator is used to\ncalculate the Higgs boson mass in the Higgs region and to show that the charged\nparticle disappears from the spectrum in the confined regime."
    },
    {
        "anchor": "Topological susceptibility and Instanton size distribution from\n  over-improved cooling: We measure the topological susceptibility by cooling with an over-improved\naction. In contrast with usual cooling, large instantons survive over-improved\ncooling {\\em indefinitely}. By varying the parameter of the over-improved\ncooling action, we measure the instanton size distribution.",
        "positive": "Study of the Asymptotic Freedom of 2D Yukawa Models on the Lattice: We investigate on the lattice the Yukawa models in 2 dimensions with Z(2) and\nU(1) symmetries. These models reduce to the usual and chiral Gross-Neveu\nmodels, respectively, when the kinetic and the selfcoupling terms of the scalar\nfield are turned off. The numerical data and mean field arguments suggest that,\nat least for some range of the scalar field hopping parameter, fermion mass is\ndynamically generated for arbitrarily weak Yukawa coupling. The models are\nasymptotically free in this coupling, like the Gross-Neveu models, even when\nthe scalar quartic selfcoupling is strong."
    },
    {
        "anchor": "2D O(3) + 2D QG: It has been suggested that the peak in the specific heat observed numerically\nfor random surface actions with extrinsic curvature on dynamical lattices might\nbe the result of a low mass bound state in an asymptotically free theory,\nrather than the signal for a real phase transition. The $O(3)$ model on a fixed\nlattice displays just such behaviour, but in general transitions appear to be\nweakened when the models concerned are put on dynamical lattices (ie coupled to\n2d quantum gravity). We have therefore performed simulations of the $O(3)$\nmodel on dynamical $\\phi^3$ graphs to see if there is still a peak in the\nspecific heat and compared the results with those on fixed lattices.",
        "positive": "Electromagnetic mass splittings of the low lying hadrons and quark\n  masses from 2+1 flavor lattice QCD+QED: Results are presented for the electromagnetic mass splittings of the low\nlying hadrons.\n  These are used to determine the non-degenerate light quark masses.\n  It is found that m_u=2.24(10)(34), m_d=4.65(15)(32), and $m_s=97.6(2.9)(5.5)$\nMeV (MSbar scheme, 2 GeV scale). The first error is statistical and the second\nsystematic. We find the lowest order electromagnetic splitting\n(m_pi+-m_pi0)_QED=3.38(23) MeV, the splittings including next-to-leading order,\n(m_pi+-m_pi0)_QED=4.50(23) MeV, (m_K+-m_K0)_QED=1.87(10) MeV, and the m_u !=\nm_d contribution to the kaon mass difference, (m_K+-m_K0)_(m_u-m_d)=-5.840(96)\nMeV.\n  All errors are statistical only, and the next-to-leading order pion splitting\nis only approximate; it does not contain all next-to-leading order\ncontributions. We also computed the proton-neutron mass difference, including\nfor the first time, QED interactions in a realistic 2+1 flavor calculation. We\nfind $(m_p-m_n)_{\\rm QED}=0.383(68)$ MeV, (m_p-m_n)_(m_u-m_d)=-2.51(14) MeV,\nand the total m_p-m_n=-2.13(16)(70) MeV, where the first error is statistical,\nand the second, part of the systematic error. We use domain wall fermions and\nthe Iwasaki gauge action (gauge coupling beta=2.13). We use two lattice sizes,\n16^3 and 24^3, to address finite volume effects. Non-compact QED is treated in\nthe quenched approximation.\n  We present new results for the electromagnetic low energy constants in SU(3)\nand SU(2) partially-quenched chiral perturbation theory to the next-to-leading\norder, obtained from fits to our data.\n  Detailed analysis of systematic errors in our results and methods for\nimproving them are discussed. Finally, new analytic results for SU(2)_L x\nSU(2)_R-plus-kaon chiral perturbation theory, including the one-loop logs\nproportional to alpha_em*m, are given."
    },
    {
        "anchor": "Twisted mass QCD in the charm sector: We present preliminary results for the charm quark mass $m_c$ and the $D$ and\n$D_s$ mesons decay constants $f_D$ and $f_{D_s}$ from a lattice QCD calculation\nwith ${\\rm N_f}$ = 2 dynamical fermions. We use the twisted mass fermionic\naction defined at maximal twist so that physical quantities are automatically\n${\\cal O}(a)$ improved. Two lattice spacings are considered. The charm quark\nmass has been renormalised in the RI-MOM scheme. After a matching to the $\\msb$\nscheme, we obtain from the simulation at a fine lattice ($a \\sim 0.09$ fm)\n$m_c^{\\msb}(m_c) = 1.481 \\pm 0.022 \\pm 0.092$ GeV, $f_D = 205 \\pm 13 \\pm 17$\nMeV, $f_{D_s} = 271 \\pm 6 \\pm 6$ MeV and from the simulation at the finer\nlattice ($a \\sim 0.07$ fm) $m_c^{\\msb}(m_c) = 1.474 \\pm 0.041 \\pm 0.132$ GeV,\n$f_D = 230 \\pm 31 \\pm 8$ MeV and $f_{D_s} = 264 \\pm 5 \\pm 8$ MeV. We chose\nthree renormalisation conditions to determine $m_c$: the spread between the\nfinal results contributes to the systematic error. At both lattice spacings,\nparticularly at the finer one, the error on $m_c$ is dominated by present\nuncertainty on the renormalisation constant $Z_P$, which should be reduced\nbefore performing a reliable continuum limit.",
        "positive": "Extensively parallelizable chiral fermion: Chiral symmetry is a key to investigating quantum physics, from condensed\nmatter to particle physics. We propose a novel way of realizing a chiral\nfermion, known as the overlap-Dirac operator, without explicitly calculating\nthe low modes of the Wilson-Dirac operator. We introduce a projection operator\ninspired by the Sakurai-Sugiura method and formulate the exact sign function\nand overlap-Dirac operator with a contour-integral form. Like the\nSakurai-Sugiura method, the proposing method is multi-scale parallelizable,\nwhich fits the multi-core/multi-GPGPU paradigm. We confirm that the quality of\nchiral symmetry realized with the proposed method is sufficient for double\nprecision. We evaluate the strong scaling of the proposing method."
    },
    {
        "anchor": "Tensor renormalization group study of the 3d $O(2)$ model: We calculate thermodynamic potentials and their derivatives for the\nthree-dimensional $O(2)$ model using tensor-network methods to investigate the\nwell-known second-order phase transition. We also consider the model at\nnon-zero chemical potential to study the Silver Blaze phenomenon, which is\nrelated to the particle number density at zero temperature. Furthermore, the\ntemperature dependence of the number density is explored using asymmetric\nlattices. Our results for both zero and non-zero magnetic field, temperature,\nand chemical potential are consistent with those obtained using other methods.",
        "positive": "Singular Vertices in the Strong Coupling Phase of Four--Dimensional\n  Simplicial Gravity: We study four--dimensional simplicial gravity through numerical simulation\nwith special attention to the existence of singular vertices, in the strong\ncoupling phase, that are shared by abnormally large numbers of four--simplices.\nThe second order phase transition from the strong coupling phase into the weak\ncoupling phase could be understood as the disappearance of the singular\nvertices. We also change the topology of the universe from the sphere to the\ntorus."
    },
    {
        "anchor": "Geometric Algorithm for Abelian-Gauge Models: Motivated by the sign problem in several systems, we have developed a\ngeometric simulation algorithm based on the strong coupling expansion which can\nbe applied to abelian pure gauge models. We have studied the algorithm in the\nU(1) model in 3 and 4 dimensions, and seen that it is practical and is\nsimilarly efficient to the standard heat-bath algorithm, but without the\nergodicity problems which comes from the presence of vortices. We have also\napplied the algorithm to the Ising gauge model at the critical point, and we\nfind hints of a better asymptotic behaviour of the autocorrelation time, which\ntherefore suggests the possibility of a smaller dynamical critical exponent\nwith respect to the standard heat-bath algorithm.",
        "positive": "The Static Approximation of Heavy-Light Quark-Systems - A Systematic\n  Lattice Study: We present a study of {\\it finite} $a$ and {\\it volume} effects of the\nleptonic decay constant $f$ of heavy pseudoscalar mesons in the static\napproximation. This study is performed on a number of lattices at $\\beta=$\n5.74,~6.0 and 6.26 covering sizes from about 0.7~$fm$ to 2~$fm$. We confirm\nthat beyond 1.5~$fm$ the volume dependence is negligible. By carefully\nanalysing results obtained using different trial wave functions for the heavy\nmeson we find no dependence on the smearing. We also give results for the mass\ndifference of the scalar - pseudoscalar and the $\\Lambda _{b}$ - pseudoscalar.\nUsing the mass of the pseudoscalar meson we estimate the distance of string\nbreaking in the static quark potential."
    },
    {
        "anchor": "Infrared and ultraviolet properties of the Landau gauge quark propagator: We present a current summary of a program to study the quark propagator using\nlattice QCD. We use the Overlap and ``Asqtad'' quark actions on a number of\nlattice ensembles to assess systematic errors. We comment on the place of this\nwork amongst studies of QCD Green's functions in other formulations. A\npreliminary calculation of the running quark mass is presented.",
        "positive": "Approximate Actions for Lattice QCD Simulation: We describe a systematic approach to generating approximate actions for the\nlattice simulation of QCD. Three different tuning conditions are defined to\nmatch approximate with true actions, and it is shown that these three\nconditions become equivalent when the approximate and true actions are\nsufficiently close. We present a detailed study of approximate actions in the\nlattice Schwinger model together with an exploratory study of full QCD at\nunphysical parameter values. We find that the technicalities of the approximate\naction approach work quite well. However, very delicate tuning is necessary to\nfind an approximate action which gives good predictions for all physical\nobservables. Our best view of the immediate applicability of the methods we\ndescribe is to allow high statistics studies of particular physical observables\nafter a low statistics full fermion simulation has been used to prepare the\nstage."
    },
    {
        "anchor": "Emergent spin: Quantum mechanics and relativity in the continuum imply the well known\nspin-statistics connection. However for particles hopping on a lattice, there\nis no such constraint. If a lattice model yields a relativistic field theory in\na continuum limit, this constraint must \"emerge\" for physical excitations. We\ndiscuss a few models where a spin-less fermion hopping on a lattice gives\nexcitations which satisfy the continuum Dirac equation. This includes such well\nknown systems such as graphene and staggered fermions.",
        "positive": "A First Principles Estimate of Finite Size Effects in Quark-Gluon Plasma\n  Formation: Using lattice simulations of quenched QCD we estimate the finite size effects\npresent when a gluon plasma equilibrates in a slab geometry, i.e., finite width\nbut large transverse dimensions. Significant differences are observed in the\nfree energy density for the slab when compared with bulk behavior. A small\nshift in the critical temperature is also seen. The free energy required to\nliberate heavy quarks relative to bulk is measured using Polyakov loops; the\nadditional free energy required is on the order of 30-40 MeV at 2-3 T_c."
    },
    {
        "anchor": "Gauge fixing, families index theory, and topological features of the\n  space of lattice gauge fields: The families index theory for the overlap lattice Dirac operator is applied\nto derive topological features of the space of SU(N) lattice gauge fields on\nthe 4-torus: The topological sectors, specified by the fermionic topological\ncharge, are shown to contain noncontractible even-dimensional spheres when\n$N\\ge3$, and noncontractible circles in the N=2 case. We describe how certain\nobstructions to the existence of gauge fixings without the Gribov problem in\nthe continuum setting correspond on the lattice to obstructions to the\ncontractibility of these spheres and circles. We also point out a canonical\nconnection on the space of lattice gauge fields with monopole-like\nsingularities associated with the spheres.",
        "positive": "Determination of Freeze-out Conditions from Lattice QCD Calculations: Freeze-out conditions in Heavy Ion Collisions are generally determined by\ncomparing experimental results for ratios of particle yields with theoretical\npredictions based on applications of the Hadron Resonance Gas model. We discuss\nhere how this model dependent determination of freeze-out parameters may\neventually be replaced by theoretical predictions based on equilibrium QCD\nthermodynamics."
    },
    {
        "anchor": "Hyperscaling in the Broken Symmetry Phase of Dyson's Hierarchical Model: We use polynomial truncations of the Fourier transform of the local measure\nto calculate the connected q-point functions of Dyson's hierarchical model in\nthe broken symmetry phase. We show that accurate values of the connected 1, 2\nand 3 point functions can be obtained at large volume and in a limited range of\nconstant external field coupled linearly to the field variable. We introduce a\nnew method to obtain the correct infinite volume and zero external field\nextrapolations. We extract the leading critical exponents and show that they\nobey the scaling and hyperscaling relations with an accuracy ranging from 10^-5\nto 5 10^-3. We briefly discuss how to improve the method of calculation.",
        "positive": "Monopoles in Lattice QCD with Abelian Projection as Quantum Monopoles: Within the context of the Abelian Projection of QCD monopole-like quantum\nexcitations of gauge fields are studied. We start with certain classical\nsolutions, of the SU(2) Yang-Mills field equations, which are not monopole-like\nand whose energy density diverges as $r \\to \\infty$. These divergent classical\nsolutions are then quantized using a modified version of Heisenberg's\nquantization technique for strongly interacting, nonlinear fields. The modified\nHeisenberg quantization technique leads to a system of equations with mixed\nquantum and classical degrees of freedom. By applying a Feynman path\nintegration over the quantum degrees of freedom the quantum-averaged solution\ngives a nondivergent, monopole-like configuration after Abelian Projection."
    },
    {
        "anchor": "Recent Progress in Lattice QCD: Recent progress in Lattice QCD is highlighted. After a brief introduction to\nthe methodology of lattice computations the presentation focuses on three main\ntopics: Hadron Spectroscopy, Hadron Structure and Lattice Flavor Physics. In\neach case a summary of recent computations of selected quantities is provided.",
        "positive": "Validity of ChPT -- is M_\u03c0=135 MeV small enough ?: I discuss the practical convergence of the SU(2) ChPT series in the meson\nsector, based on 2+1 flavor lattice data by the Wuppertal-Budapest and\nBudapest-Marseille-Wuppertal collaborations. These studies employ staggered and\nclover-improved Wilson fermions, respectively. In both cases large box volumes\nand several lattice spacings are used, and the pion masses reach down to the\nphysical mass point. We conclude that LO and NLO low-energy constants can be\ndetermined with controlled systematics, if there is sufficient data between the\nphysical mass point and about 350 MeV pion mass. Exploratory LO+NLO+NNLO fits\nwith a wider range reveal some distress of the chiral series near M_\\pi ~ 400\nMeV and suggest a complete breakdown beyond M_\\pi ~ 500 MeV."
    },
    {
        "anchor": "Thermal quarkonium physics in the pseudoscalar channel: The pseudoscalar correlator is an ideal lattice probe for thermal\nmodifications to quarkonium spectra, given that it is not compromised by a\ncontribution from a large transport peak. We construct a perturbative spectral\nfunction incorporating resummed thermal effects around the threshold and vacuum\nasymptotics above the threshold, and compare the corresponding imaginary-time\ncorrelators with continuum-extrapolated lattice data for quenched SU(3) at\nseveral temperatures. Modest differences are observed, which may originate from\nnon-perturbative mass shifts or renormalization factors, however no resonance\npeaks are needed for describing the quenched lattice data for charmonium at and\nabove T ~ 1.1Tc ~ 350 MeV. For comparison, in the bottomonium case a good\ndescription of the lattice data is obtained with a spectral function containing\na single thermally broadened resonance peak.",
        "positive": "Deconstructing {\\\" U}nsal-Yaffe Reconfinement: In the UY reconfined phase on a lattice the thermal trace is over states\ntransforming in all $SU(N)/Z(N)$ irreducible representations as opposed to only\nover $SU(N)$ singlets in the standard formulation. As $N\\to\\infty$, on a finite\nlattice, the usual Hilbert space becomes orthogonal to the deformed one.\nConcerns about the extended UY proposal for large $N$ Eguchi-Kawai reduction\nare raised."
    },
    {
        "anchor": "Nonperturbative renormalization of the supercurrent in $\\mathcal{N} = 1$\n  Supersymmetric Yang-Mills Theory: In this work, we study the nonperturbative renormalization of the\nsupercurrent operator in $\\mathcal{N} = 1$ Supersymmetric Yang-Mills (SYM)\ntheory, using a gauge-invariant renormalization scheme (GIRS). The proposed\nprescription addresses successfully the unwanted mixing of the supercurrent\nwith other operators of equal or lower dimension, which respect the same global\nsymmetries. This mixing is introduced by the unavoidable breaking of\nsupersymmetry on the lattice. In GIRS all gauge-noninvariant operators, which\nmix with the supercurrent, are excluded from the renormalization procedure. The\none remaining mixing operator is accessible by numerical simulations. We\npresent results for the renormalization of the supercurrent using a GIRS\nscheme. We also compute at one-loop order the conversion matrix which relates\nthe nonperturbative renormalization factors in GIRS to the reference scheme\n$\\bar{\\rm MS}$.",
        "positive": "Non-perturbative renormalization of the axial current in $N_f = 3$\n  lattice QCD with Wilson fermions and tree-level improved gauge action: We non-perturbatively determine the renormalization factor of the axial\nvector current in lattice QCD with $N_f=3$ flavors of Wilson-clover fermions\nand the tree-level Symanzik-improved gauge action. The (by now standard)\nrenormalization condition is derived from the massive axial Ward identity and\nit is imposed among Schr\\\"{o}dinger functional states with large overlap on the\nlowest lying hadronic state in the pseudoscalar channel, in order to reduce\nkinematically enhanced cutoff effects. We explore a range of couplings relevant\nfor simulations at lattice spacings of $\\approx 0.09$ fm and below. An\ninterpolation formula for $Z_A(g_0^2)$, smoothly connecting the\nnon-perturbative values to the 1-loop expression, is provided together with our\nfinal results."
    },
    {
        "anchor": "Improvement of the Staggered Fermion Operators: We present a complete and detailed derivation of the finite lattice spacing\ncorrections to staggered fermion matrix elements. Expanding upon arguments of\nSharpe, we explicitly implement the Symanzik improvement program demonstrating\nthe absence of order $a$ terms in the Symanzik improved action. We propose a\ngeneral program to improve fermion operators to remove $O(a)$ corrections from\ntheir matrix elements, and demonstrate this program for the examples of matrix\nelements of fermion bilinears and $B_K$. We find the former does have $O(a)$\ncorrections while the latter does not.",
        "positive": "Localization in SU(3) gauge theory: In this paper we study the localization transition of Dirac eigenmodes in\nquenched QCD. We determined the temperature dependence of the mobility edge in\nthe quark-gluon plasma phase near the deconfining critical temperature. We\ncalculated the critical temperature where all of the localized modes disappear\nfrom the spectrum and compared it with the critical temperature of the\ndeconfining transition. We found that the localization transition happens at\nthe same temperature as the deconfining transition which indicates a strong\nrelation between the two phenomena."
    },
    {
        "anchor": "The magnetized (2+1)-dimensional Gross-Neveu model at finite density: We perform a lattice study of the ($2+1$)-dimensional Gross-Neveu model in a\nbackground magnetic field $B$ and at non-zero chemical potential $\\mu$. The\ncomplex-action problem arising in our simulations using overlap fermions is\nunder control. For $B=0$ we observe a first-order phase transition in $\\mu$\neven at non-vanishing temperatures. Our main finding, however, is that the rich\nphase structure found in the limit of infinite flavor number $N_\\mathrm{f}$ is\nwashed out by the fluctuations present at $N_\\mathrm{f}=1$. We find no evidence\nfor inverse magnetic catalysis, i.e., the decrease of the order parameter of\nchiral symmetry breaking with $B$ for $\\mu$ close to the chiral phase\ntransition. Instead, the magnetic field tends to enhance the breakdown of\nchiral symmetry for all values of $\\mu$ below the transition. Moreover, we find\nno trace of spatial inhomogeneities in the order parameter. We briefly comment\non the potential relevance of our results for QCD.",
        "positive": "An Estimate of alpha_S from Bottomonium in Unquenched QCD: We estimate the strong coupling constant from the perturbative expansion of\nthe plaquette. The scale is set by the 2S-1S and 1P-1S splittings in\nbottomonium which are computed in NRQCD on dynamical gauge configurations with\nnf=2 degenerate Wilson quarks at intermediate masses. We have increased the\nstatistics of our spectrum calculation in order to reliably extrapolate in the\nsea-quark mass. We find a value of alpha_MS(m_Z) = 0.1118(26) which is somewhat\nlower than previous estimates within NRQCD."
    },
    {
        "anchor": "K to pi and K to 0 in 2+1 Flavor Partially Quenched Chiral Perturbation\n  Theory: We calculate results for K to pi and K to 0 matrix elements to\nnext-to-leading order in 2+1 flavor partially quenched chiral perturbation\ntheory. Results are presented for both the Delta I=1/2 and 3/2 channels, for\nchiral operators corresponding to current-current, gluonic penguin, and\nelectroweak penguin 4-quark operators. These formulas are useful for studying\nthe chiral behavior of currently available 2+1 flavor lattice QCD results, from\nwhich the low energy constants of the chiral effective theory can be\ndetermined. The low energy constants of these matrix elements are necessary for\nan understanding of the Delta I=1/2 rule, and for calculations of\nepsilon'/epsilon using current lattice QCD simulations.",
        "positive": "Operator improvement for Ginsparg-Wilson fermions: The improvement of fermionic operators for Ginsparg-Wilson fermions is\ninvestigated. We present explicit formulae for improved Green's functions,\nwhich apply both on-shell and off-shell."
    },
    {
        "anchor": "Finite volume effects in pion-kaon scattering and reconstruction of the\n  kappa(800) resonance: Simulating the kappa(800) on the lattice is a challenging task that starts to\nbecome feasible due to the rapid progress in recent-years lattice QCD\ncalculations. As the resonance is broad, special attention to finite-volume\neffects has to be paid, because no sharp resonance signal as from avoided level\ncrossing can be expected. In the present article, we investigate the finite\nvolume effects in the framework of unitarized chiral perturbation theory using\nnext-to-leading order terms. After a fit to meson-meson partial wave data,\nlattice levels for piK scattering are predicted. In addition, levels are shown\nfor the quantum numbers in which the sigma(600), f_0(980), a_0(980), phi(1020),\nK*(892), and rho(770) appear, as well as the repulsive channels. Methods to\nextract the kappa(800) signal from the lattice spectrum are presented. Using\npseudo-data, we estimate the precision that lattice data should have to allow\nfor a clear-cut extraction of this resonance. To put the results into context,\nin particular the required high precision on the lattice data, the sigma(600),\nthe P-wave resonances K*(892) and rho(770), and the repulsive piK, pipi phases\nare analyzed as well.",
        "positive": "Variational description of statistical field theories using Daubechies'\n  wavelets: We investigate the description of statistical field theories using\nDaubechies' orthonormal compact wavelets on a lattice. A simple variational\napproach is used to extend mean field theory and make predictions for the\nfluctuation strengths of wavelet coefficients and thus for the correlation\nfunction. The results are compared to Monte Carlo simulations. We find that\nwavelets provide a reasonable description of critical phenomena with only a\nsmall number of variational parameters. This lets us hope for an implementation\nof the renormalization group in wavelet space."
    },
    {
        "anchor": "Helium nuclei, deuteron and dineutron in 2+1 flavor lattice QCD: We calculate the binding energies for multi-nucleon bound states with the\nnuclear mass number less than or equal to 4 in 2+1 flavor QCD at the lattice\nspacing of a = 0.09 fm employing a relatively heavy quark mass corresponding to\nm_pi = 0.51 GeV. To distinguish a bound state from attractive scattering\nstates, we investigate the volume dependence of the energy shift between the\nground state and the state of free nucleons by changing the spatial extent of\nthe lattice from 2.9 fm to 5.8 fm. We conclude that ^4He, ^3He, deuteron and\ndineutron are bound at m_pi = 0.51 GeV. We compare their binding energies with\nthose in our quenched studies and also with several previous investigations.",
        "positive": "The bottomonium melting from screening correlators at high temperature: We study the bottomonium screening masses in a 2+1 flavor QCD medium on the\nlattice using the Highly Improved Staggered Quark(HISQ) discretization for the\nquarks. We focus on a wide temperature range in the region $350~{\\rm MeV}\\le T\n< 1000 ~{\\rm MeV}$, and perform our calculations on three different lattice\nspacings to control the lattice cut-off effects, corresponding to temporal\nlattice extent of $N_\\tau=8,10,12$. From a detailed study of the temperature\ndependence of screening masses we conclude that while the $\\eta_b(1S)$ and\n$\\Upsilon(1S)$ states melt at $T>500$ MeV, the scalar and axial-vector states\n$\\chi_{b0}(1P)$ and $h_b(1P)$ melt already at $T>350$ MeV."
    },
    {
        "anchor": "Localisation of Dirac modes in finite-temperature $\\mathbb{Z}_2$ gauge\n  theory on the lattice: The low-lying Dirac modes become localised at the finite-temperature\ntransition in QCD and in other gauge theories, suggesting a general connection\nbetween their localisation and deconfinement. The simplest model where this\nconnection can be tested is $\\mathbb{Z}_2$ gauge theory in 2+1 dimensions. We\nshow that in this model the low modes in the staggered Dirac spectrum are\ndelocalised in the confined phase and become localised in the deconfined phase.\nWe also show that localised modes correlate with disorder in the Polyakov loop\nconfiguration, in agreement with the \"sea/island\" picture of localisation, and\nwith negative plaquettes. These results further support the conjecture that\nlocalisation and deconfinement are closely related.",
        "positive": "Mitigating topological freezing using out-of-equilibrium simulations: Motivated by the recently-established connection between Jarzynski's equality\nand the theoretical framework of Stochastic Normalizing Flows, we investigate a\nprotocol relying on out-of-equilibrium lattice Monte Carlo simulations to\nmitigate the infamous computational problem of topological freezing. We test\nour proposal on $2d$ $\\mathrm{CP}^{N-1}$ models and compare our results with\nthose obtained adopting the Parallel Tempering on Boundary Conditions proposed\nby M. Hasenbusch, obtaining comparable performances. Our work thus sets the\nstage for future applications combining our Monte Carlo setup with machine\nlearning techniques."
    },
    {
        "anchor": "Relation between bare lattice coupling and MSbar coupling at one loop\n  with general lattice fermions: A compact general integral formula is derived from which the fermionic\ncontribution to the one-loop coefficient in the perturbative expansion of the\nMSbar coupling in powers of the bare lattice coupling can be extracted. It is\nseen to reproduce the known results for unimproved naive, staggered and Wilson\nfermions, and has advantageous features which facilitate the evaluation in the\ncase of improved lattice fermion formulations. This is illustrated in the case\nof Wilson clover fermions, and an expression in terms of known lattice\nintegrals is obtained in this case which gives the coefficient to much greater\nnumerical accuracy than in the previous literature.",
        "positive": "A local factorization of the fermion determinant in lattice QCD: We introduce a factorization of the fermion determinant in lattice QCD with\nWilson-type fermions that leads to a bosonic action which is local in the block\nfields. The interaction among gauge fields on distant blocks is mediated by\nmultiboson fields located on the boundaries of the blocks. The resultant\nmultiboson domain-decomposed hybrid Monte Carlo passes extensive numerical\ntests carried out by measuring standard gluonic observables. The combination of\nthe determinant factorization and of the one of the propagator, that we put\nforward recently, paves the way for multilevel Monte Carlo integration in the\npresence of fermions. We test this possibility by computing the disconnected\ncorrelator of two flavor-diagonal pseudoscalar densities, and we observe a\nsignificant increase of the signal-to-noise ratio due to a two-level\nintegration."
    },
    {
        "anchor": "Computation of Structure Functions From a Lattice Hamiltonian: We compute structure functions in the Hamiltonian formalism on a momentum\nlattice using a physically motivated regularisation that links the maximal\nparton number to the lattice size. We show for the $\\phi ^4 _{3+1}$ theory that\nour method allows to describe continuum physics. The critical line and the\nrenormalised mass spectrum close to the critical line are computed and scaling\nbehaviour is observed in good agreement with L{\\\"u}scher and Weisz' lattice\nresults. We then compute distribution functions and find a $Q^2$ behaviour and\nthe typical peak at $x_B\\rightarrow 0$ like in $QCD$.",
        "positive": "Sparse modeling approach to obtaining the shear viscosity from smeared\n  correlation functions: We propose the sparse modeling method to estimate the spectral function from\nthe smeared correlation functions. We give a description of how to obtain the\nshear viscosity from the correlation function of the renormalized\nenergy-momentum tensor (EMT) measured by the gradient flow method ($C(t,\\tau)$)\nfor the quenched QCD at finite temperature. The measurement of the renormalized\nEMT in the gradient flow method reduces a statistical uncertainty thanks to its\nproperty of the smearing. However, the smearing breaks the sum rule of the\nspectral function and the over-smeared data in the correlation function may\nhave to be eliminated from the analyzing process of physical observables. In\nthis work, we demonstrate that the sparse modeling analysis in the\nintermediate-representation basis (IR basis), which connects between the\nMatsubara frequency data and real frequency data. It works well even using very\nlimited data of $C(t,\\tau)$ only in the fiducial window of the gradient flow.\nWe utilize the ADMM algorithm which is useful to solve the LASSO problem under\nsome constraints. We show that the obtained spectral function reproduces the\ninput smeared correlation function at finite flow-time. Several systematic and\nstatistical errors and the flow-time dependence are also discussed."
    },
    {
        "anchor": "Quark masses and low energy constants in the continuum from the tadpole\n  improved clover ensembles: We present the light-flavor quark masses and low energy constants using the\n2+1 flavor full-QCD ensembles with stout smeared clover fermion action and\nSymanzik gauge actions. Both the fermion and gauge actions are tadpole improved\nself-consistently. The simulations are performed on 11 ensembles at 3 lattice\nspacings $a\\in[0.05,0.11]$ fm, 4 spatial sizes $L\\in[2.5, 5.1]$ fm, 7 pion\nmasses $m_{\\pi}\\in[135,350]$ MeV, and several values of the strange quark mass.\nThe quark mass is defined through the partially conserved axial current (PCAC)\nrelation and renormalized to $\\overline{\\mathrm{MS}}$ 2 GeV through the\nintermediate regularization independent momentum subtraction (RI/MOM) scheme.\nThe systematic uncertainty of using the symmetric momentum subtraction (SMOM)\nscheme is also included. Eventually, we predict $m_u=2.45(22)(20)$ MeV,\n$m_d=4.74(11)(09)$ MeV, and $m_s=98.8(2.9)(4.7)$ MeV with the systematic\nuncertainties from lattice spacing determination, continuum extrapolation and\nrenormalization constant included. We also obtain the chiral condensate\n$\\Sigma^{1/3}=268.6(3.6)(0.7)$ MeV and the pion decay constant $F=86.6(7)(1.4)\n$ MeV in the $N_f=2$ chiral limit, and the next-to-leading order low energy\nconstants $\\ell_3=2.43(54)(05)$ and $\\ell_4=4.322(75)(96)$.",
        "positive": "Dirac spectrum and the BEC-BCS crossover in QCD at nonzero isospin\n  asymmetry: For large isospin asymmetries, perturbation theory predicts the QCD ground\nstate to be a superfluid phase of $u$ and $\\bar{d}$ Cooper pairs. This phase,\nwhich is denoted as the BCS phase, is expected to be smoothly connected to the\nstandard phase with Bose-Einstein condensation (BEC) of charged pions at\n$\\mu_I\\ge m_\\pi/2$ by an analytic crossover. A first hint for the existence of\nthe BCS phase, which is likely characterised by the presence of both,\ndeconfinement and charged pion condensation, is coming from the lattice\nobservation that the deconfinement crossover smoothly penetrates into the BEC\nphase. To further scrutinize the existence of the BCS phase, in this\nproceedings article we investigate the complex spectrum of the massive Dirac\noperator in 2+1-flavor QCD at nonzero temperature and isospin chemical\npotential. The spectral density near the origin is related to the BCS gap via a\ngeneralization of the Banks-Casher relation to the case of complex Dirac\neigenvalues (derived for the zero-temperature, high-density limits of QCD at\nnonzero isospin chemical potential)."
    },
    {
        "anchor": "Homotopy, monopoles and 't Hooft tensor in QCD with generic gauge group: We study monopoles and corresponding 't Hooft tensor in QCD with a generic\ncompact gauge group. This issue is relevant to the understanding of color\nconfinement in terms of dual symmetry.",
        "positive": "Quantum Simulation of Finite Temperature Schwinger Model via Quantum\n  Imaginary Time Evolution: We study the Schwinger model at finite-temperature regime using a\nquantum-classical hybrid algorithm. The preparation of thermal state on quantum\ncircuit presents significant challenges. To address this, we adopt the Thermal\nPure Quantum (TPQ) state approach and apply the Quantum Imaginary Time\nEvolution (QITE) algorithm to implement the necessary imaginary time evolution.\nWe first compute the chiral condensate in the massless Schwinger model,\nverifying its consistency with the analytical solution. We then simulate the\nmassive Schwinger model with non-zero topological $\\theta$-term to investigate\nthe temperature and $\\theta$-dependence of the chiral condensate. Our method\nworks well even at non-zero $\\theta$ regime, while the conventional lattice\nMonte Carlo method suffers from the sign problem in this system."
    },
    {
        "anchor": "Determination of light quark masses from the electromagnetic splitting\n  of pseudoscalar meson masses computed with two flavors of domain wall\n  fermions: We determine the light quark masses from lattice QCD simulations\nincorporating the electromagnetic interaction of valence quarks. The meson\nmasses are calculated on lattice QCD configurations generated by the RBC\nCollaboration for two flavors of dynamical domain wall fermions, which are\ncombined with QED configurations generated via quenched non-compact lattice\nQED. The electromagnetic part of the pion mass splitting is found to be\n$m_{\\pi^+}-m_{\\pi^0}=4.12(21)$ MeV, where only the statistical error is quoted,\nand similarly for the kaon, 1.443(55) MeV. Our results for the light quark\nmasses are $m_u^{\\rm\\bar{MS}}$(2 GeV)=$3.02(27)(19)$ MeV, $m_d^{\\rm\\bar{MS}}$(2\nGeV)=$5.49(20)(34)$ MeV, and $m_s^{\\rm\\bar{MS}}$(2 GeV)=$119.5(56)(74)$ MeV,\nwhere the first error is statistical and the second systematic. By averaging\nover $\\pm e$ to cancel ${\\cal O}(e)$ noise exactly on each combined gauge field\nconfiguration, we are able to work at physical $\\alpha=1/137$ and obtain very\nsmall statistical errors. In our calculation, several sources of systematic\nerror remain, including finite volume, non-zero lattice spacing, chiral\nextrapolation, quenched QED, and quenched strange quark, which may be more\nsignificant than the errors quoted above.",
        "positive": "Lattice QCD with 8 Light Quark Flavors: QCD with eight flavors is studied on $16^3\\times N_t$ lattices with $N_t=4$,\n6, 8, 16 and 32, a dynamical quark mass $ma=0.015$ and lattice coupling\n$\\beta=6/g^2$ between 4.5 and 5.0. For $N_t=16$ and 32, hadron masses and\nscreening lengths are computed for a variety of valence quark masses. The\npreviously observed, strong, first-order transition for $N_t=4$, 6 and 8 is\nseen, for $N_t=16$, to become a $\\beta$-independent, zero-temperature\ntransition characterized by a factor of $\\approx 3$ change in lattice scale.\nThis strong, first-order transition restores chiral symmetry, at least for\n$N_t=4$, 6 and 8, producing a chirally symmetric, weak-coupling phase. However,\nas $N_t$ increases to 16, the chiral symmetry properties of the weak-coupling\nside of the zero-temperature transition are unclear and offer a hint of a\nnormal, finite-temperature, chiral symmetry breaking transition in the\nweak-coupling phase."
    },
    {
        "anchor": "Study of energy-momentum tensor correlation function in $N_f=2+1$ full\n  QCD for QGP viscosities: We study correlation functions of the energy-momentum tensor (EMT) in\n$(2+1)$-flavor full QCD to evaluate QGP viscosities. We adopt nonperturbatively\nimproved Wilson fermion and Iwasaki gauge action. Our degenerate $u$, $d$ quark\nmass is rather heavy with $m_{\\pi}/m_{\\rho}\\simeq0.63$, while the $s$ quark\nmass is set to approximately its physical value. Performing simulations on\nlattices with $N_t=16$ to 6 at a fine lattice spacing of $a=0.07$ fm, the\ntemperature range of $T\\simeq174$--$464$ MeV is covered using the fixed-scale\napproach. We attempt to compute viscosities by three steps: (1) calculate two\npoint correlation functions of non-perturbatively renormalized EMT applying the\ngradient flow method, (2) derive the spectral function from correlation\nfunction, and (3) extract viscosities from the spectral function applying the\nKubo formula. We report on the status of the project and present preliminary\nresults for the shear viscosity in the high temperature phase.",
        "positive": "Magnetic catalysis in the (2+1)-dimensional Gross-Neveu model: We study the Gross-Neveu model in $2+1$ dimensions in an external magnetic\nfield $B$. We first summarize known mean-field results, obtained in the limit\nof large flavor number $N_\\mathrm{f}$, before presenting lattice results using\nthe overlap discretization to study one reducible fermion flavor,\n$N_\\mathrm{f}=1$. Our findings indicate that the magnetic catalysis phenomenon,\ni.e., an increase of the chiral condensate with the magnetic field, persists\nbeyond the mean-field limit for temperatures below the chiral phase transition\nand that the critical temperature grows with increasing magnetic field. This is\nin contrast to the situation in QCD, where the broken phase shrinks with\nincreasing $B$ while the condensate exhibits a non-monotonic $B$-dependence\nclose to the chiral crossover, and we comment on this discrepancy. We do not\nfind any trace of inhomogeneous phases induced by the magnetic field."
    },
    {
        "anchor": "Light quark masses in N_f = 2+1 lattice QCD with Wilson fermions: We present a lattice QCD determination of light quark masses with three\nsea-quark flavours ($N_f = 2+1$). Bare quark masses are known from PCAC\nrelations in the framework of CLS lattice computations with a\nnon-perturbatively improved Wilson-Clover action and a tree-level Symanzik\nimproved gauge action. They are fully non-perturbatively improved, including\nthe recently computed Symanzik counter-term $b_{\\rm A} - b_{\\rm P}$. The mass\nrenormalisation at hadronic scales and the renormalisation group running over a\nwide range of scales are known non-perturbatively in the Schr\\\"odinger\nfunctional scheme. In the present paper we perform detailed extrapolations to\nthe physical point, obtaining (for the four-flavour theory) $m_{u/d}(2{\\rm\nGeV}) = 3.54(12)(9)$ MeV and $m_s(2{\\rm GeV}) = 95.7(2.5)(2.4)$ MeV in the\n$\\bar{MS}$ scheme. For the mass ratio we have $m_s/m_{u/d} = 27.0(1.0)(0.4)$.\nThe RGI values in the three-flavour theory are $M_{u/d} = 4.70(15)(12)$ MeV and\n$M_s = 127.0(3.1)(3.2)$ MeV.",
        "positive": "Flavour symmetry restoration and kaon weak matrix elements in quenched\n  twisted mass QCD: We simulate two variants of quenched twisted mass QCD (tmQCD), with\ndegenerate Wilson quarks of masses equal to or heavier than half the strange\nquark mass. We use Ward identities in order to measure the twist angles of the\ntheory and thus check the quality of the tuning of mass parameters to a physics\ncondition which stays constant as the lattice spacing is varied. Flavour\nsymmetry breaking in tmQCD is studied in a framework of two fully twisted and\ntwo standard Wilson quark flavours, tuned to be degenerate in the continuum.\nComparing pseudoscalar masses, obtained from connected quark diagrams made of\ntmQCD and/or standard Wilson quark propagators, we confirm that flavour\nsymmetry breaking effects, which are at most 5%, decrease as we approach the\ncontinuum limit. We also compute the pseudoscalar decay constant in the\ncontinuum limit, with reduced systematics. As a consequence of improved tuning\nof the mass parameters at $\\beta = 6.1$, we reanalyse our previous $B_K$\nresults. Our main phenomenological findings are $r_0 f_K = 0.421(7)$ and $\\hat\nB_K = 0.735(71)$."
    },
    {
        "anchor": "Precise Neutron Electric Form Factor from Lattice QCD: A new calculation of the neutron electric form factor is described.\nPreliminary results for the connected part on a $20^{3}\\times 32$ lattice are\npresented. The methods for calculating the disconnected part are briefly\ndescribed.",
        "positive": "New extended interpolating operators for hadron correlation functions: New extended interpolating operators made of quenched three dimensional\nfermions are introduced in the context of lattice QCD. The mass of the 3D\nfermions can be tuned in a controlled way to find a better overlap of the\nextended operators with the states of interest. The extended operators have\ngood renormalisation properties and are easy to control when taking the\ncontinuum limit. Moreover the short distance behaviour of the two point\nfunctions built from these operators is greatly improved. The operators have\nbeen numerically implemented and a comparison to point sources and Jacobi\nsmeared sources has been performed on the new CLS configurations."
    },
    {
        "anchor": "Strange electromagnetic form factors of the nucleon with $N_f = 2 + 1$\n  $\\mathcal{O}(a)$-improved Wilson fermions: We present results for the strange contribution to the electromagnetic form\nfactors of the nucleon computed on the CLS ensembles with $N_f=2+1$ flavors of\n$\\mathcal{O}(a)$-improved Wilson fermions and an $\\mathcal{O}(a)$-improved\nvector current. Several source-sink separations are investigated in order to\nestimate the excited-state contamination. We calculate the form factors on six\nensembles with lattice spacings in the range of $a=0.049-0.086\\,\\text{fm}$ and\npion masses in the range of $m_\\pi=200-360\\,\\text{MeV}$, which allows for a\ncontrolled chiral and continuum extrapolation. In the computation of the\nquark-disconnected contributions we employ hierarchical probing as a variance\nreduction technique.",
        "positive": "The Kramers equation simulation algorithm I. Operator analysis: Using an operatorial formalism, we study the Kramers equation and its\napplications to numerical simulations. We obtain classes of algorithms which\nmay be made precise at every desired order in the time step $\\epsilon$ and with\na set of free parameters which can be used to reduce autocorrelations. We show\nthat it is possible to use a global Metropolis test to restore Detailed\nBalance."
    },
    {
        "anchor": "A lattice study of the spin structure of the Lambda hyperon: The internal spin structure of the Lambda is of special importance for the\nunderstanding of the spin structure of hadrons in general. The comparison\nbetween the nucleon and Lambda allows for a test of the relevant\nflavour-symmetry breaking effects. Using nonperturbatively O(a) improved Wilson\nfermions in the quenched approximation we have calculated the first moments of\nthe unpolarised, longitudinally polarised and transversity quark distribution\nfunctions in the Lambda. The results indicate that flavour symmetry breaking\nhas little effect on the internal spin structure, in accordance with model\nbased expectations.",
        "positive": "Partial-wave and helicity operators for the scattering of two hadrons in\n  lattice QCD: Partial-wave operators for lattice QCD are developed in order to facilitate\nthe identification of the spins of two-hadron scattering states corresponding\nto zero total momentum. Taking the periodic boundary conditions for lattice\nstates into account, orthogonal sets of partial-wave operators for orbital\nangular momentum are identified. When combined with the intrinsic spins of the\nhadrons, orthogonal sets of parent operators for total angular momentum $J$ and\nprojection $M$ are obtained. The parent operators are subduced to irreducible\nrepresentations of the octahedral group in order to obtain descendant operators\nfor use in lattice calculations. The descendant operators retain orthogonality\nwith respect to $J$. The spin of a state can be identified by the spin of\nparent operators that dominate creation of the state. For nonzero total\nmomentum, operators are developed for a range of helicities and they are\nsubduced to irreducible representations corresponding to the different\ndirections of total momentum. Sets of operators that include a sufficient range\nof helicities allow identification of spin $J$ when a state couples to\noperators with helicities less than or equal to $J$, but not to operators with\nhigher helicities."
    },
    {
        "anchor": "$B\u03c0$-state contamination in $B$-meson observables: Multi-particle states with additional pions are expected to result in a\nnon-negligible excited-state contamination in lattice simulations. We show that\nheavy meson chiral perturbation theory can be employed to calculate the\ncontamination due to two-particle $B\\pi$ states in various $B$-meson\nobservables like the $B$-meson decay constant and the $BB^*\\pi$ coupling. We\nwork in the static limit and to next-to-leading order in the chiral expansion.\nThe $B\\pi$ states are found to typically overestimate the observables at the\nfew percent level depending on the size of two currently unknown NLO low-energy\ncoefficients. A strategy to independently measure one of them with the 3-point\nfunction of the light axial vector current will be discussed.",
        "positive": "Cluster dynamics for first-order phase transitions in the Potts model: An algorithm for Monte Carlo simulations is proposed in which the parameter\ncontrolling the strength of the transition becomes a dynamical variable and in\nwhich efficient transitions are achieved by cluster steps. It allows to avoid\nthe strongly suppressed tunneling between the phases by travelling easily via\nthe second order region. Numerical results for the Potts model are presented\nwhich demonstrate the advantages of the method."
    },
    {
        "anchor": "Chiral properties of light mesons with $N_f=2+1$ overlap fermions: We present an update of the light meson spectrum with $N_f$=2+1 overlap\nfermions on a $16^3\\times 48$ lattice at five different up and down quark\nmasses and two strange quark masses. Based on our experience with the previous\nsimulation with $N_f=2$, we carry out the chiral extrapolation with the\nprediction of the chiral perturbation theory at the next-to-next-to leading\norder. We also check the consistency of our analysis by using alternative\nchiral extrapolation with a reduced theory in which the strange quark mass is\nintegrated out.",
        "positive": "Distribution of Energy-Momentum Tensor around a Static Quark in the\n  Deconfined Phase of SU(3) Yang-Mills Theory: Energy momentum tensor (EMT) characterizes the response of the vacuum as well\nas the thermal medium under the color electromagnetic fields. We define the EMT\nby means of the gradient flow formalism and study its spatial distribution\naround a static quark in the deconfined phase of SU(3) Yang-Mills theory on the\nlattice. Although no significant difference can be seen between the EMT\ndistributions in the radial and transverse directions except for the sign, the\ntemporal component is substantially different from the spatial ones near the\ncritical temperature $T_c$. This is in contrast to the prediction of the\nleading-order thermal perturbation theory. The lattice data of the EMT\ndistribution also indicate the thermal screening at long distance and the\nperturbative behavior at short distance."
    },
    {
        "anchor": "Strange nucleon electromagnetic form factors from lattice QCD: We evaluate the strange nucleon electromagnetic form factors using an\nensemble of gauge configurations generated with two degenerate maximally\ntwisted mass clover-improved fermions with mass tuned to approximately\nreproduce the physical pion mass. In addition, we present results for the\ndisconnected light quark contributions to the nucleon electromagnetic form\nfactors. Improved stochastic methods are employed leading to high-precision\nresults. The momentum dependence of the disconnected contributions is fitted\nusing the model-independent z-expansion. We extract the magnetic moment and the\nelectric and magnetic radii of the proton and neutron by including both\nconnected and disconnected contributions. We find that the disconnected light\nquark contributions to both electric and magnetic form factors are non-zero and\nat the few percent level as compared to the connected. The strange form factors\nare also at the percent level but more noisy yielding statistical errors that\nare typically within one standard deviation from a zero value.",
        "positive": "Probing the chiral phase transition of N_f=2 clover fermions with\n  valence overlap fermions: Overlap fermions are a powerful tool for investigating the chiral and\ntopological structure of the vacuum and the thermal states of QCD. We study\nvarious chiral and topological aspects of the finite temperature phase\ntransition of N_f=2 flavours of O(a) improved Wilson fermions, using valence\noverlap fermions as a probe. Particular emphasis is placed upon the analysis of\nthe spectral density and the localisation properties of the eigenmodes as well\nas on the local structure of topological charge fluctuations in the vicinity of\nthe chiral phase transition. The calculations are done on 16^3x8 lattices\ngenerated by the DIK collaboration."
    },
    {
        "anchor": "Estimating the Unquenched Strange Quark Mass from the Lattice Axial Ward\n  Identity: We present a determination of the strange quark mass for two flavours (nf=2)\nof light dynamical quarks using the axial Ward identity. The calculations are\nperformed on the lattice using O(a) improved Wilson fermions and include a\nfully non-perturbative determination of the renormalisation constant. In the\ncontinuum limit we find in the MSbar scheme at 2GeV, ms = 111(6)(4)(6)MeV using\nthe force scale r0 = 0.467fm, where the first error is statistical, the second\nand third are systematic due to the fit and scale uncertainties respectively.\nResults are also presented for the light quark mass and the chiral condensate.\nThe corresponding results are also given for r0=0.5fm.",
        "positive": "Continuum Gauge Fields from Lattice Gauge Fields: On the lattice some of the salient features of pure gauge theories and of\ngauge theories with fermions in complex representations of the gauge group seem\nto be lost. These features can be recovered by considering part of the theory\nin the continuum. The prerequisite for that is the construction of continuum\ngauge fields from lattice gauge fields. Such a construction, which is gauge\ncovariant and complies with geometrical constructions of the topological charge\non the lattice, is given in this paper. The procedure is explicitly carried out\nin the $U(1)$ theory in two dimensions, where it leads to simple results."
    },
    {
        "anchor": "Casimir scaling of SU(3) static potentials: Potentials between static colour sources in eight different representations\nare computed in four dimensional SU(3) gauge theory. The simulations have been\nperformed with the Wilson action on anisotropic lattices where the renormalised\nanisotropies have been determined non-perturbatively. After an extrapolation to\nthe continuum limit we are able to exclude any violations of the Casimir\nscaling hypothesis that exceed 5% for source separations of up to 1 fm.",
        "positive": "K^0-\\bar K^0 mixing beyond the standard model and CP-violating\n  electroweak penguins in quenched QCD with exact chiral symmetry: We present results for the \\Delta S=2 matrix elements which are required to\nstudy neutral kaon mixing in the standard model (SM) and beyond (BSM). We also\nprovide leading chiral order results for the matrix elements of the electroweak\npenguin operators which give the dominant \\Delta I=3/2 contribution to direct\nCP violation in K->\\pi\\pi decays. Our calculations were performed with\nNeuberger fermions on two sets of quenched Wilson gauge configurations at\ninverse lattice spacings of approximately 2.2 GeV and 1.5 GeV. All\nrenormalizations were implemented non-perturbatively in the RI/MOM scheme,\nwhere we accounted for sub-leading operator product expansion corrections and\ndiscretization errors. We find ratios of non-SM to SM matrix elements which are\nroughly twice as large as in the only other dedicated lattice study of these\namplitudes. On the other hand, our results for the electroweak penguin matrix\nelements are in good agreement with two recent domain-wall fermion\ncalculations. As a by-product of our study, we determine the strange quark\nmass. Our main results are summarized and discussed in Sec. VII. Within our\nstatistics, we find no evidence for scaling violations."
    },
    {
        "anchor": "Catalysis of chiral symmetry breaking by external magnetic fields in\n  three-dimensional lattice QED: The enhancement of the fermionic condensate due to the presence of both\nhomogeneous and non-homogeneous external magnetic fields is studied for\nthree-dimensional QED.",
        "positive": "2+1 flavor lattice QCD simulation with $O(a)$-improved Wilson quarks: We present simulation details and results for the light hadron spectrum in N\nf = 2 + 1 lattice QCD with the nonperturbatively O(a)-improved Wilson quark\naction and the Iwasaki gauge action. Simulations are carried out at a lattice\nspacing of 0.09 fm on a (2.9fm)^3 box using the PACS-CS computer. We employ the\nLuscher's domain-decomposed HMC algorithm with several improvements to reduce\nthe degenerate up-down quark mass toward the physical value. So far the\nresulting pseudoscalar meson mass is ranging from 702MeV down to 156MeV. We\ndiscuss on the stability and the efficiency of the algorithm. The light harden\nspectrum extrapolated at the physical point is compared with the experimental\nvalues. We also present the values of the quark masses and the pseudoscalar\nmeson decay constants."
    },
    {
        "anchor": "Complex singularities around the QCD critical point at finite densities: Partition function zeros provide alternative approach to study phase\nstructure of finite density QCD. The structure of the Lee-Yang edge\nsingularities associated with the zeros in the complex chemical potential plane\nhas a strong influence on the real axis of the chemical potential. In order to\ninvestigate what the singularities are like in a concrete form, we resort to an\neffective theory based on a mean field approach in the vicinity of the critical\npoint. The crossover is identified as a real part of the singular point. We\nconsider the complex effective potential and explicitly study the behavior of\nits extrema in the complex order parameter plane in order to see how the Stokes\nlines are associated with the singularity. Susceptibilities in the complex\nplane are also discussed.",
        "positive": "Colour Fields Computed in SU(3) Lattice QCD for the Static Tetraquark\n  System: The colour fields created by the static tetraquark system are computed in\nquenched SU(3) lattice QCD, in a 24^3 x 48 lattice at beta=6.2 corresponding to\na lattice spacing a=0.07261(85) fm. We find that the tetraquark colour fields\nare well described by a double-Y, or butterfly, shaped flux tube. The two flux\ntube junction points are compatible with Fermat points minimizing the total\nflux tube length. We also compare the diquark-diantiquark central flux tube\nprofile in the tetraquark with the quark-antiquark fundamental flux tube\nprofile in the meson, and they match, thus showing that the tetraquark flux\ntubes are composed of fundamental flux tubes."
    },
    {
        "anchor": "Delta expansion at low temperatures: In the low temperature phase of the square Ising model, we describe the\ninverse temperature beta as the function of a squared mass M and study the\ncritical behavior of beta(M) via the large M expansion. Using the\ndelta-expansion by which the large mass expansion is transformed into a series\nexhibiting expected scaling behavior, we perform the estimation of the critical\ninverse temperature beta_{c} with the help of linear differential equation to\nbe satisfied by ansatz of beta(M) near the critical point M=0. To improve the\nestimation, the leading correction exponent nu is independently estimated from\nbeta^{(2)}/beta^{(1)} and is used in the estimation of beta_{c}, giving rise to\nremarkable accuracy improvement.",
        "positive": "$SU(2)$ gauge theory in the maximally abelian gauge without monopoles: We present an algorithm for simulation of $SU(2)$ lattice gauge theory under\nthe MA gauge and first numerical results for the theory without abelian\nmonopoles. The results support the idea that nonperturbative interaction arises\nbetween monopoles and residual abelian field and the other interactions are\nperturbative. It is shown that the Gribov region for the theory with the MA\ngauge fixed is non-connected."
    },
    {
        "anchor": "Insights into the Nucleon Spin from Lattice QCD: Flavour singlet contributions to the nucleon spin are elusive due to the fact\nthat they cannot be determined directly in experiment but require\nextrapolations to the small x region. Direct calculations of these\ncontributions are possible using Lattice QCD, however, they pose a significant\ncomputational challenge due to the presence of disconnected quark line\ndiagrams. We report on recent progress in determining these sea quark\ncontributions on the lattice.",
        "positive": "Analysis of the finite temperature transition for 3 flavor QCD using\n  p4-improved staggered fermions: We present a calculation of the transition temperature for 3 flavor QCD using\np4-improved staggered fermions with two different variants of fattened links.\nWe examine various susceptibilities at two different values for the temporal\nextent - $N_t = 4$ and $N_t = 6$ - in the vicinity of the 3 flavor transition\nat vanishing chemical potential. For $N_t = 4$, we study bare quark masses in\nthe range $m_qa = 0.005$ to $m_qa = 0.1$, and for $N_t = 6$, we use $m_qa =\n0.02$ to $m_qa = 0.2$. We also calculate hadron masses and the static quark\npotential at zero temperature in order to set the scale for the transition\ntemperature and to study quark mass and cut-off dependent scaling properties of\nthe transition temperature. A comparison of the R Algorithm and the RHMC\nalgorithm for finite-temperature simulations is also made"
    },
    {
        "anchor": "The Maximal Abelian Gauge in SU(N) Gauge Theories and Thermal Monopoles\n  for N = 3: We discuss and propose a proper extension of the Abelian projection based on\nthe Maximal Abelian Gauge to SU(N) gauge theories. Based, on that, we\ninvestigate the properties of thermal Abelian monopoles in the deconfined phase\nof the SU(3) pure gauge theory. Such properties are very similar to those\nalready found for SU(2), confirming the relevance of the magnetic component\nclose to Tc and the possible condensation of thermal monopoles as the\ndeconfinement temperature is crossed from above. Moreover, we study the\ncorrelation functions among monopoles related to different U(1) subgroups,\nwhich show interesting features and reveal the presence of non-trivial\ninteractions.",
        "positive": "SU(3) lattice gauge autocorrelations with anisotropic action: We report results of autocorrelation measurements in pure $SU(3)$ lattice\ngauge theory. The computations are performed on the {\\sc convex spp1200}\nparallel platform within the {\\sc canopy} programming environment. The focus of\nour analysis is on typical autocorrelation times and optimization of the mixing\nratio between overrelaxation and pseudo-heatbath sweeps for generating gauge\nfield configurations. We study second order tadpole-improved approximations of\nthe Wilson action in the gluon sector, which offers the advantage of working on\nsmaller lattices ($8^3~\\times~16$ and $6^3~\\times$~12~--~30). We also make use\nof anisotropic lattices, with temporal lattice spacing smaller than the spatial\nspacing, which prove useful for calculating noisy correlation functions with\nlarge spatial lattice discretization (of the order of 0.4 fm)."
    },
    {
        "anchor": "Topological charge renormalization: A test case for 3-loop vacuum\n  calculations using overlap fermions and Symanzik improved gluons: We calculate perturbative renormalization properties of the topological\ncharge, using the standard lattice discretization given by a product of twisted\nplaquettes. We use the overlap and clover action for fermions, and the Symanzik\nimproved gluon action for 4- and 6-link loops.\n  We compute the multiplicative renormalization of the topological charge\ndensity to one loop; this involves only the gluon part of the action. The power\ndivergent additive renormalization of the topological susceptibility is\ncalculated to 3 loops.",
        "positive": "Mixed Action Lattice Spacing Effects on the Nucleon Axial Charge: We study the nucleon axial charge in the chiral perturbation theory for a\nmixed lattice action of Ginsparg-Wilson valence quarks and staggered sea\nquarks. In particular, we investigate the lattice spacing $a^2$-dependence of\nthe neutron to proton axial transition matrix element. By using the known\nlow-energy constants (LEC's) and an estimated value of a new LEC which appears\nin the calculation, we see a large lattice spacing effect on $g_A$."
    },
    {
        "anchor": "Gradient Flow Coupling in the SU(2) gauge theory with two adjoint\n  fermions: We study SU(2) gauge theory with two fermion flavors in the adjoint\nrepresentation. Using a clover improved HEX smeared action and the gradient\nflow running coupling allows us to simulate with larger lattice size than\nbefore. We find an infrared fixed point after a continuum extrapolation in the\nrange $4.5 \\lesssim g^{*2} \\lesssim 5$. We also measure the mass anomalous\ndimension and find the value $ 0.25 \\lesssim \\gamma^* \\lesssim 0.28 $ at the\nfixed point.",
        "positive": "The Operator Product Expansion for Radial Lattice Quantization of 3D\n  $\u03c6^4$ Theory: At its critical point, the three-dimensional lattice Ising model is described\nby a conformal field theory (CFT), the 3d Ising CFT. Instead of carrying out\nsimulations on Euclidean lattices, we use the Quantum Finite Elements method to\nimplement radially quantized critical $\\phi^4$ theory on simplicial lattices\napproaching $\\mathbb{R} \\times S^2$. Computing the four-point function of\nidentical scalars, we demonstrate the power of radial quantization by the\naccurate determination of the scaling dimensions $\\Delta_{\\epsilon}$ and\n$\\Delta_{T}$ as well as ratios of the operator product expansion (OPE)\ncoefficients $f_{\\sigma \\sigma \\epsilon}$ and $f_{\\sigma \\sigma T}$ of the\nfirst spin-0 and spin-2 primary operators $\\epsilon$ and $T$ of the 3d Ising\nCFT."
    },
    {
        "anchor": "Relations among Supersymmetric Lattice Gauge Theories via Orbifolding: We show how to derive Catterall's supersymmetric lattice gauge theories\ndirectly from the general principle of orbifolding followed by a variant of the\nusual deconstruction. These theories are forced to be complexified due to a\nclash between charge assignments under U(1)-symmetries and lattice assignments\nin terms of scalar, vector and tensor components for the fermions. Other\nprescriptions for how to discretize the theory follow automatically by\norbifolding and deconstruction. We find that Catterall's complexified model for\nthe two-dimensional N=(2,2) theory has two independent preserved\nsupersymmetries. We comment on consistent truncations to lattice theories\nwithout this complexification and with the correct continuum limit. The\nconstruction of lattice theories this way is general, and can be used to derive\nnew supersymmetric lattice theories through the orbifolding procedure. As an\nexample, we apply the prescription to topologically twisted four-dimensional\nN=2 supersymmetric Yang-Mills theory. We show that a consistent truncation is\nclosely related to the lattice formulation previously given by Sugino.",
        "positive": "Towards an Effective Importance Sampling in Monte Carlo Simulations of a\n  System with a Complex Action: The sign problem is a notorious problem, which occurs in Monte Carlo\nsimulations of a system with a partition function whose integrand is not\npositive. One way to simulate such a system is to use the factorization method\nwhere one enforces sampling in the part of the configuration space which gives\nimportant contribution to the partition function. This is accomplished by using\nconstraints on some observables chosen appropriately and minimizing the free\nenergy associated with their joint distribution functions. These observables\nare maximally correlated with the complex phase. Observables not in this set\nessentially decouple from the phase and can be calculated without the sign\nproblem in the corresponding \"microcanonical\" ensemble. These ideas are applied\non a simple matrix model with very strong sign problem and the results are\nfound to be consistent with analytic calculations using the Gaussian Expansion\nMethod."
    },
    {
        "anchor": "A Preliminary Lattice Study of the Glue in the Nucleon: About half the mass of a hadron is given from gluonic contributions. In this\ntalk we calculate the chromo-electric and chromo-magnetic components of the\nnucleon mass. These computations are numerically difficult due to gluon field\nultra-violet fluctuations. Nevertheless a high statistics feasibility run using\nquenched Wilson fermions seems to show reasonable signals.",
        "positive": "Properties of B-Mesons in Lattice QCD: The results of an extensive study of B-meson properties in quenched lattice\nQCD are presented. The studies are carried out in the static quark limit where\nthe b-quark is taken to be infinitely massive. Our computations rely on a\nmultistate smearing method introduced previously, with smearing functions\ngenerated from a relativistic lattice quark model. Systematic errors arising\nfrom excited state contamination, finite volume effects, and the chiral\nextrapolation for the light quarks are estimated. We obtain continuum results\nfor the mass splitting M_{B_s}- M_{B_u} = 86 (+/-)12(stat) {+7/-9}(syst) MeV,\nthe ratio of decay constants f_{B_s}/f_{B_u} = 1.22 (+/-)0.04(stat) (+/-)0.02\n(syst). For the B-meson decay constant we separately exhibit the sizable\nuncertainties in the extrapolation to the continuum limit a -> 0 and higher\norder perturbative matching. We obtain f_{B} = 188 (+/-)23(stat) (+/-)15(syst)\n{+26/-0}(extrap) (+/-)14 (pert) MeV. ----- [Postscript version of paper\navailable by anonymous ftp at fncrd6.fnal.gov. The file is fb.ps in\nsubdirectory theory.]"
    },
    {
        "anchor": "Partially Quenched Chiral Perturbation Theory and a Massless Up Quark: A\n  Lattice Calculation of the Light-Quark-Mass Ratio: The nontrivial topological structure of the QCD gauge vacuum generates a CP\nbreaking term in the QCD Lagrangian. However, measurements of the neutron\nelectric dipole moment have demonstrated that the term's coefficient is\nunnaturally small, a dilemma known as the strong CP problem. A massless up\nquark is one potential solution, as the term could then be absorbed through\nchiral rotations. Through the light-quark-mass ratio m_u / m_d, leading order\nChiral Perturbation Theory appears to rule this scenario out. However, the\nKaplan-Manohar ambiguity demonstrates that certain strong next-to-leading order\ncorrections are indistinguishable from an up quark mass. Only a direct\ncalculation of the Gasser-Leutwyler coefficient combination 2 L_8 - L_5 can\nresolve the issue. We carry out such a calculation, using partially quenched\nN_f = 3 staggered fermions and hypercubic blocking, and make a quantitative\nassessment of our systematic error. We find 2 L_8 - L_5 = (0.22 +/- 0.14) x\n10^-3, which corresponds to a light-quark-mass ratio of m_u / m_d = 0.408 +/-\n0.035. Thus, the massless-up-quark solution to the strong CP problem is ruled\nout. This is the first calculation of its type to use a physical number of\nlight quarks, N_f = 3, and the first determination of 2 L_8 - L_5 to include a\ncomprehensive study of statistical error.",
        "positive": "$K_L$ - $K_S$ mass difference computed with a 171 MeV pion mass: In this work, we used a $32^3 \\times 64 \\times 32$, 2+1 flavor domain wall\nlattice with Iwasaki+DSDR gauge action. The pion mass is 171 MeV and the kaon\nmass is 492 MeV. We implement the Glashow-Iliopoulos-Maiani (GIM) cancellation\nusing charm quark masses of 750 MeV and 592 MeV. This is an intermediate\ncalculation, in that we are using both a coarse lattice spacing (1/a = 1.37GeV)\nso we expect significant discretization error coming from charm quark mass and\nwe are also using unphysical kinematics for the pion. The main purpose of this\ncalculation is to study the contribution from the two-pion intermediate state\nwhen the energy of a two-pion state is lower than that of the kaon, as well as\nthe corresponding finite volume correction to the $\\Delta M_K$."
    },
    {
        "anchor": "Measuring the interface tension when the electroweak phase transition\n  becomes weak: We measure the interface tension near the phase transition endpoint of the 3d\nSU(2)-Higgs model. The tunnel correlation length method is used and compared to\nother approaches. A modified scaling behaviour for the mass gap as function of\nthe transverse area is proposed.",
        "positive": "Weak coupling expansion of massless QCD with a Ginsparg-Wilson fermion\n  and axial U(1) anomaly: We discuss the weak coupling expansion of massless QCD with the Dirac\noperator which is derived by Neuberger based on the overlap formalism and\nsatisfies the Ginsparg-Wilson relation. The axial U(1) anomaly associated to\nthe chiral transformation proposed by Luscher is calculated as an application\nand is shown to have the correct form of the topological charge density for\nperturbative backgrounds. The coefficient of the anomaly is evaluated as a\nwinding number related to a certain five-dimensional fermion propagator."
    },
    {
        "anchor": "Spin-3/2 baryons from an anisotropic lattice QCD action: The mass spectrum of baryons in the spin-3/2 sector is computed in quenched\nlattice QCD using a tadpole-improved anisotropic action. Both isospin 1/2 and\n3/2 (the traditional decuplet) are considered, as well as members that contain\nstrange quarks. States with positive and negative parities are isolated by\nparity projection, while states with spin-3/2 and spin-1/2 are separated by\nspin projection. The extent to which spin projection is needed is examined. The\nissue of optimal interpolating field is also investigated. The results are\ndiscussed in relation to previous calculations and experiment.",
        "positive": "Determination of the running coupling constant $\u03b1_s$ for Nf=2+1 QCD\n  with the Schroedinger functional scheme: We present an evaluation of the running coupling constant and the quark mass\nrenormalization factor for $N_f=2+1$ QCD. The Schr\\\"odinger functional scheme\nis used as the intermediate scheme to carry out non-perturbative running from\nthe low energy region, where physical input is introduced, to deep in the high\nenergy perturbative region, where conversion to the ${\\ovl{\\rm MS}}$ scheme is\nsafely performed.\n  For numerical simulations we adopted Iwasaki gauge action and\nnon-perturbatively improved Wilson fermion action with the clover term. Seven\nrenormalization scales are used to cover from low to high energy region and\nthree lattice spacings to take the continuum limit at each scale.\n  Physical inputs are introduced from the previous $N_f=2+1$ simulation of the\nCP-PACS/JL-QCD collaboration, which covered the up-down quark mass range\nheavier than $m_\\pi\\sim 500$ MeV, and that of PACS-CS collaboration for much\nlighter quark masses down to $m_\\pi=155$ MeV."
    },
    {
        "anchor": "Instanton Effects in Hadron Spectroscopy in SU(2) (Lattice) Gauge Theory: We describe quenched spectroscopy in SU(2) gauge theory using smoothed gauge\nfield configurations. We investigate the properties of quarks moving in\ninstanton background field configurations, where the sizes and locations of the\ninstantons are taken from simulations of the full gauge theory. By themselves,\nthese multi-instanton configurations do not confine quarks, but they induce\nchiral symmetry breaking.",
        "positive": "Off-diagonal Gluon Mass Generation and Infrared Abelian Dominance in\n  Maximally Abelian Gauge in SU(3) Lattice QCD: In SU(3) lattice QCD formalism, we propose a method to extract gauge fields\nfrom link-variables analytically. With this method, we perform the first study\non effective mass generation of off-diagonal gluons and infrared Abelian\ndominance in the maximally Abelian (MA) gauge in the SU(3) case. Using SU(3)\nlattice QCD, we investigate the propagator and the effective mass of the gluon\nfields in the MA gauge with U(1)$_3 \\timesU(1)_8$ Landau gauge fixing. The\nMonte Carlo simulation is performed on $16^4$ at $\\beta$=5.7, 5.8 and 6.0 at\nthe quenched level. The off-diagonal gluons behave as massive vector bosons\nwith the approximate effective mass $M_{\\mathrm{off}} \\simeq\n1.1-1.2\\mathrm{GeV}$ in the region of $r =0.3-0.8$fm, and the propagation is\nlimited within a short range, while the propagation of diagonal gluons remains\neven in a large range. In this way, infrared Abelian dominance is shown in\nterms of short-range propagation of off-diagonal gluons. Furthermore, we\ninvestigate the functional form of the off-diagonal gluon propagator. The\nfunctional form is well described by the four-dimensional Euclidean Yukawa-type\nfunction $e^{-m_{\\rm off}r}/r$ with $m_{\\rm off} \\simeq 1.3-1.4\\mathrm{GeV}$\nfor $r = 0.1- 0.8$ fm. This also indicates that the spectral function of\noff-diagonal gluons has the negative-value region."
    },
    {
        "anchor": "The Status of D-Theory: Field theories are usually quantized by performing a path integral over\nconfigurations of classical fields. This is the case both in perturbation\ntheory and in Wilson's nonperturbative lattice field theory. D-theory is an\nalternative nonperturbative formulation of field theory in which classical\nfields emerge from the low-energy collective dynamics of discrete quantum\nvariables (quantum spins and their gauge analogs -- quantum links) which\nundergo dimensional reduction. D-theory was developed some time ago as a\ndiscrete approach to U(1) and SU(2) pure gauge theories, extended to SU(N)\ngauge theories and full QCD, and also applied to a variety of other models. On\nthe practical side, D-theory provides a framework for the development of\nefficient numerical methods, such as cluster algorithms. For example, in the\nD-theory formulation of CP(N-1) models one can simulate efficiently at non-zero\nchemical potential or at non-zero vacuum angle theta. On the conceptual side,\nD-theory offers a natural solution for the nonperturbative hierarchy problem of\nchiral symmetry in QCD. We also take a broader nonperturbative view on\nfundamental physics and speculate that D-theory variables -- i.e. quantum spins\nand quantum links -- may be promising candidates for the physical degrees of\nfreedom that Nature has chosen to regularize the standard model physics at\nultra-short distances.",
        "positive": "Numerical Implementation of Gauge-Fixed Fourier Acceleration: In hybrid Monte Carlo evolution, by imposing a physical gauge condition,\nsimple Fourier acceleration can be used to generate conjugate momenta and\npotentially reduce critical slowing down. This modified gauge evolution\nalgorithm does not change the gauge-independent properties of the resulting\ngauge field configurations. We describe this algorithm and it numerical\nimplementation."
    },
    {
        "anchor": "Dark matter on the lattice: Several collaborations have recently performed lattice calculations aimed\nspecifically at dark matter, including work with SU(2), SU(3), SU(4) and SO(4)\ngauge theories to represent the dark sector. Highlights of these studies are\npresented here, after a reminder of how lattice calculations in QCD itself are\nhelping with the hunt for dark matter.",
        "positive": "A new lattice gauge action without scaling artifacts: I describe a new way of constructing a gauge action that eliminates scaling\nartifacts, by writing the continuum formalism in terms of \"gauge links\"\n(Schwinger line integrals) and using the optimal SLAC representation of the\nlattice derivative. Computational performance can be maintained by implementing\nthe action as a \"stochastic\" operator, as has been recently implemented in the\nMILC code for the optimal D-slash operator and the antialiasing filter."
    },
    {
        "anchor": "Non-Perturbative Gauge-Higgs Unification in Five Dimensions: We study the phase diagram and mass spectrum of an $SU(2)$ Gauge-Higgs\nUnification scenario on a five-dimensional orbifold.We observe spontaneous\nsymmetry breaking within the Higgs phase of the theory and, in the vicinity of\na newly discovered phase, we find that the ratio of Higgs to gauge boson masses\ntakes a Standard Model-like value. Precisely in this region of the phase\ndiagram, we observe dimensional reduction via localisation.",
        "positive": "QED on the lattice and numerical perturbative computation of $g-2$: We compute the electron $g$ factor to the $\\mathcal{O}(\\alpha^5)$ order on\nthe lattice in quenched QED. We first study finite volume corrections in\nvarious IR regularization methods to discuss which regularization is optimal\nfor our purpose. We find that in QED$_L$ the finite volume correction to the\neffective mass can have different parametric dependences depending on the size\nof Euclidean time $t$ and match the `naive on-shell result' only at very large\n$t$ region, $t \\gg L$. We adopt finite photon mass regularization to suppress\nfinite volume effects exponentially and also discuss our strategy for selecting\nsimulation parameters and the order of extrapolations to efficiently obtain the\n$g$ factor. We perform lattice simulation using small lattices to test\nfeasibility of our calculation strategy. This study can be regarded as an\nintermediate step toward giving the five-loop coefficient independently of the\npreceding studies."
    },
    {
        "anchor": "Peculiar Properties of SU(2) Gauge Field Thermodynamics on a Finite\n  Lattice. Calculation of Beta-function: The new method of nonperturbative calculation of the beta-function in the\nlattice gauge theory is proposed. The method is based on the finite size\nscaling hypothesis.",
        "positive": "Baryon-Baryon Interactions from Lattice QCD: We report on new attempt to investigate baryon-baryon interactions in lattice\nQCD. From the Bethe-Salpeter (BS) wave function, we have successfully extracted\nthe nucleon-nucleon ($NN$) potentials in quenched QCD simulations, which\nreproduce qualitative features of modern $NN$ potentials. The method has been\nextended to obtain the tensor potential as well as the central potential and\nalso applied to the hyperon-nucleon ($YN$) interactions, in both quenched and\nfull QCD."
    },
    {
        "anchor": "Low-Lying Eigenvalues of the Wilson-Dirac Operator: An exploratory study of the low-lying eigenvalues of the Wilson-Dirac\noperator and their corresonding eigenvectors is presented. Results for the\neigenvalues from quenched and unquenched simulations are discussed. The\neigenvectors are studied with respect to their localization properties in the\nquenched approximation for the cases of SU(2) and SU(3).",
        "positive": "Soliton form factors from lattice simulations: The form factor provides a convenient way to describe properties of\ntopological solitons in the full quantum theory, when semiclassical concepts\nare not applicable. It is demonstrated that the form factor can be calculated\nnumerically using lattice Monte Carlo simulations. The approach is very general\nand can be applied to essentially any type of soliton. The technique is\nillustrated by calculating the kink form factor near the critical point in\n1+1-dimensional scalar field theory. As expected from universality arguments,\nthe result agrees with the exactly calculable scaling form factor of the\ntwo-dimensional Ising model."
    },
    {
        "anchor": "Thermodynamics of SU(N) Yang-Mills theories in 2+1 dimensions I - The\n  confining phase: We compute the equation of state in the confining phase of SU(N) Yang-Mills\ntheories with N=2, 3, 4, 5 and 6 colors in 2+1 dimensions, via lattice\nsimulations. At low enough temperatures, the results are accurately described\nby a gas of glueballs, including all known states below the two-particle\nthreshold. Close to the deconfinement temperature, however, this prediction\nunderestimates the numerical results, and the contribution from heavier\nglueballs has to be included. We show that the spectral density of the latter\ncan be accurately described using a simple bosonic string model.",
        "positive": "Probing nucleon strange and charm distributions with lattice QCD: We present the first lattice-QCD calculation of the unpolarized strange and\ncharm parton distribution functions using large-momentum effective theory\n(LaMET). We use a lattice ensemble with 2+1+1 flavors of highly improved\nstaggered quarks (HISQ) generated by MILC collaboration, with lattice spacing\n$a\\approx 0.12$ fm and $M_\\pi \\approx 310$ MeV, and clover valence fermions\nwith two valence pion masses: 310 and 690 MeV. We use momentum-smeared sources\nto improve the signal up to nucleon boost momentum $P_z=2.18$ GeV, and\ndetermine nonperturbative renormalization factors in RI/MOM scheme. We compare\nour lattice results with the matrix elements obtained from matching the PDFs\nfrom CT18NNLO and NNPDF3.1NNLO global fits. Our data support the assumptions of\nstrange-antistrange and charm-anticharm symmetry that are commonly used in\nglobal PDF fits, and we find smaller than expected parton distribution at mid\nto small $x$."
    },
    {
        "anchor": "Comment on \"Percolation Properties of the 2D Heisenberg Model\": We comment on a recent paper by All\\`es et al.",
        "positive": "Non-Abelian dual superconductivity in SU(3) Yang-Mills theory: dual\n  Meissner effect and type of the vacuum: We have proposed the non-Abelian dual superconductivity picture for quark\nconfinement in the SU(3) Yang-Mills (YM) theory, and have given numerical\nevidences for the restricted-field dominance and the non-Abelian magnetic\nmonopole dominance in the string tension by applying a new formulation of the\nYM theory on a lattice. To establish the non-Abelian dual superconductivity\npicture for quark confinement, we have observed the non-Abelian dual Meissner\neffect in the SU(3) Yang-Mills theory by measuring the chromoelectric flux\ncreated by the quark-antiquark source, and the non-Abelian magnetic monopole\ncurrents induced around the flux. We conclude that the dual superconductivity\nof the SU(3) Yang-Mills theory is strictly the type I and that this type of\ndual superconductivity is reproduced by the restricted field and the\nnon-Abelian magnetic monopole part, in sharp contrast to the SU(2) case: the\nborder of type I and type II."
    },
    {
        "anchor": "A new approach to the two-dimensional $\u03c3$-model with a topological\n  charge: Based on character decomposition, a dual transformation is introduced leading\nto two formulations of the theory which should allow for a removal/softening of\nthe sign problem in the original version. Very preliminar numerical results are\ncommented and remaining problems discussed.",
        "positive": "On Gauged Renormalisation Group Transformations of Lattice Fermions: We construct a hierarchy of lattice fermions, where the coarser lattice Dirac\noperator is the Schur complement of the block UL decomposition of the finer\nlattice operator. We show that the construction is an exact gauged\nrenormalisation group transformation of the lattice action. In particular,\nusing such a transformation and the QCDLAB tool, it is shown how to implement\nthe Ginsparg-Wilson strategy for chiral fermions in the presence of a dynamical\ngauge field. The scheme allows, for the first time, a full multigrid algorithm\nfor lattice quarks."
    },
    {
        "anchor": "Lines of Fisher's zeros as separatrices for complex renormalization\n  group flows: We extend the renormalization group transformation based on the two-lattice\nmatching to the complex inverse temperature plane for Dyson's hierarchical\nIsing model. We consider values of the dimensional parameter above, below and\nexactly at the critical value where the ordered low temperature phase becomes\nimpossible for a real positive temperature. We show numerically that, as the\nvolume increases, the Fisher's zeros appear to accumulate along lines that\nseparate the flows ending on different fixed points. We justify these findings\nin terms of finite size scaling. We argue that the location of the Fisher's\nzeros at large volume determine the phase diagram in the complex plane. We\ndiscuss the implications for nontrivial infrared fixed points in lattice gauge\ntheory.",
        "positive": "Learning Lattice Quantum Field Theories with Equivariant Continuous\n  Flows: We propose a novel machine learning method for sampling from the\nhigh-dimensional probability distributions of Lattice Field Theories, which is\nbased on a single neural ODE layer and incorporates the full symmetries of the\nproblem. We test our model on the $\\phi^4$ theory, showing that it\nsystematically outperforms previously proposed flow-based methods in sampling\nefficiency, and the improvement is especially pronounced for larger lattices.\nFurthermore, we demonstrate that our model can learn a continuous family of\ntheories at once, and the results of learning can be transferred to larger\nlattices. Such generalizations further accentuate the advantages of machine\nlearning methods."
    },
    {
        "anchor": "Lattice calculation of the heavy quark potential at non-zero temperature: We calculated the real and imaginary parts of the static quark anti-quark\npotential at T>0 in 2+1 flavor QCD using correlators of Wilson lines in Coulomb\ngauge and lattices with temporal extent N_tau=12. We find that the real part of\nthe potential is larger than the singlet free energy but smaller than the zero\ntemperature potential. The imaginary part of the potential is similar in size\nto the perturbative HTL result.",
        "positive": "Seeking the Equation of State of Non-Compact Lattice QED: We perform a high statistics calculation of the equation of state for\nnon-compact QED on large lattices. The calculation extends to fermionic\ncorrelation lengths of $\\approx 8$, and it is combined with a finite size\nscaling analysis of the lattice data."
    },
    {
        "anchor": "Electroweak Phase Transitions: Recent developments on the four dimensional (4d) lattice studies of the\nfinite temperature electroweak phase transition (EWPT) are summarized. The\nphase diagram is given in the continuum limit. The finite temperature\nSU(2)-Higgs phase transition is of first order for Higgs-boson masses m_H<66.5\n+/- 1.4 GeV. Above this endpoint only a rapid cross-over can be seen. The full\n4d result agrees completely with that of the dimensional reduction\napproximation. The Higgs-boson endpoint mass in the Standard Model (SM) would\nbe 72.1 +/- 1.4 GeV. Taking into account the LEP Higgs-boson mass lower bound\nexcludes any EWPT in the SM. A one-loop calculation of the static potential in\nthe SU(2)-Higgs model enables a precise comparison between lattice simulations\nand perturbative results. The most popular extension of the SM, the Minimal\nSupersymmetric SM (MSSM) is also studied on 4d lattices.",
        "positive": "Unwrapping phase fluctuations in one dimension: Correlation functions in one-dimensional complex scalar field theory provide\na toy model for phase fluctuations, sign problems, and signal-to-noise problems\nin lattice field theory. Phase unwrapping techniques from signal processing are\napplied to lattice field theory in order to map compact random phases to\nnoncompact random variables that can be numerically sampled without sign or\nsignal-to-noise problems. A cumulant expansion can be used to reconstruct\naverage correlation functions from moments of unwrapped phases, but points\nwhere the field magnitude fluctuates close to zero lead to ambiguities in the\ndefinition of the unwrapped phase and significant noise at higher orders in the\ncumulant expansion. Phase unwrapping algorithms that average fluctuations over\nphysical length scales improve, but do not completely resolve, these issues in\none dimension. Similar issues are seen in other applications of phase\nunwrapping, where they are found to be more tractable in higher dimensions."
    },
    {
        "anchor": "A High Precision Study of the QQ(bar) Potential from Wilson Loops in the\n  Regime of String Breaking: For lattice QCD with two sea quark flavours we compute the static quark\nantiquark potential V(R) in the regime where string breaking is expected. In\norder to increase statistics, we make full use of the lattice information by\nincluding all lattice vectors R to any possible lattice separation in the\ninfrared regime. The corresponding paths between the lattice points are\nconstructed by means of a generalized Bresenham algorithm as known from\ncomputer graphics. As a results we achieve a determination of the unquenched\npotential in the range .8 to 1.5 fm with hitherto unknown precision.\nFurthermore, we demonstrate some error reducing methods for the evaluation of\nthe transition matrix element between two- and four-quark states.",
        "positive": "A lattice regularization of Weyl fermions in a gravitational background: We report on a lattice fermion formulation with a curved domain-wall mass\nterm to nonperturbatively describe fermions in a gravitational background. In\nour previous work in 2022, we showed under the time-reversal symmetry that the\nedge-localized massless Dirac fermion appears on one and two-dimensional\nspherical domain-walls and the spin connection is induced on the lattice in a\nconsistent way with continuum theory. In this work, we extend our study to the\nShamir type curved domain-wall fermions without the time-reversal symmetry. We\nfind in the free fermion case that a single Weyl fermion appears on the edge,\nand feels gravity through the induced spin connection. With a topologically\nnontrivial $U(1)$ gauge potential, however, we find an oppositely chiral zero\nmode at the center where the gauge field is singular."
    },
    {
        "anchor": "Scanning the Topological Sectors of the QCD Vacuum with Hybrid Monte\n  Carlo: We address a long standing issue and determine the decorrelation efficiency\nof the Hybrid Monte Carlo algorithm (HMC), for full QCD with Wilson fermions,\nwith respect to vacuum topology. On the basis of five state-of-the art QCD\nvacuum field ensembles (with 3000 to 5000 trajectories each and\nm_pi/m_rho-ratios in the regime >0.56, for two sea quark flavours) we are able\nto establish, for the first time, that HMC provides sufficient tunneling\nbetween the different topological sectors of QCD. This will have an important\nbearing on the prospect to determine, by lattice techniques, the topological\nsusceptibility of the vacuum, and topology sensitive quantities like the spin\ncontent of the proton, or the eta' mass.",
        "positive": "Stability of lattice QCD simulations and the thermodynamic limit: We study the spectral gap of the Wilson--Dirac operator in two-flavour\nlattice QCD as a function of the lattice spacing $a$, the space-time volume $V$\nand the current-quark mass $m$. It turns out that the median of the probability\ndistribution of the gap scales proportionally to $m$ and that its width is\npractically equal to $a/\\sqrt{V}$. In particular, numerical simulations are\nsafe from accidental zero modes in the large-volume regime of QCD."
    },
    {
        "anchor": "More on the flavor dependence of $m_\\varrho / f_\u03c0$: In previous work, arXiv:1905.01909, we have calculated the $m_\\varrho /\nf_\\pi$ ratio in the chiral and continuum limit for $SU(3)$ gauge theory coupled\nto $N_f = 2,3,4,5,6$ fermions in the fundamental representation. The main\nresult was that this ratio displays no statistically significant\n$N_f$-dependence. In the present work we continue the study of the\n$N_f$-dependence by extending the simulations to $N_f = 7, 8, 9, 10$. Along the\nway we also study in detail the $N_f$-dependence of finite volume effects on\nlow energy observables and a particular translational symmetry breaking\nunphysical, lattice artefact phase specific to staggered fermions.",
        "positive": "Sphaleron rate of $N_f=2+1$ QCD: We compute the sphaleron rate of $N_f=2+1$ QCD at the physical point for a\nrange of temperatures $200$ MeV $\\lesssim T \\lesssim 600$ MeV. We adopt a\nstrategy recently applied in the quenched case, based on the extraction of the\nrate via a modified version of the Backus-Gilbert method from\nfinite-lattice-spacing and finite-smoothing-radius Euclidean topological charge\ndensity correlators. The physical sphaleron rate is finally computed by\nperforming a continuum limit at fixed physical smoothing radius, followed by a\nzero-smoothing extrapolation. Dynamical fermions were discretized using the\nstaggered formulation, which is known to yield large lattice artifacts for the\ntopological susceptibility. However, we find them to be rather mild for the\nsphaleron rate."
    },
    {
        "anchor": "QCD Monopoles on the Lattice and Gauge Invariance: The long standing problem is solved why the number and the location of\nmonopoles observed in Lattice configurations depend on the choice of the gauge\nused to detect them, in contrast to the obvious requirement that monopoles, as\nphysical objects, must have a gauge-invariant status.\n  It is proved, by use of non-abelian Bianchi identities, that monopoles are\nindeed gauge-invariant: the technique used to detect them has instead an\nefficiency which depends on the choice of the abelian projection, in a known\nand controllable way.",
        "positive": "Quark number susceptibilities, strangeness and dynamical confinement: We report first results on the strange quark number susceptibility, chi_s,\nover a large range of temperatures, mainly in the plasma phase of QCD. Chi_s\njumps across the phase transition temperature, T_c, and grows rapidly with\ntemperature above but close to T_c. For all quark masses and susceptibilities\nin the entire temperature range studied, we found significant departures from\nideal-gas values. We also observed a strong correlation between these\nquantities and the susceptibility in the scalar/pseudo-scalar channel,\nsupporting ideas of ``dynamical confinement'' in the high temperature phase of\nthe QCD plasma."
    },
    {
        "anchor": "Gribov horizon under the (lattice) microscope: The infinite color-Coulomb energy of color-charged states is related to\nenhanced density of near-zero modes of the Faddeev-Popov operator in Coulomb\ngauge. We confirm the enhancement in numerical simulations and show that it is\ntied to the presence of percolating center vortex configurations.",
        "positive": "On the spectrum of the QCD Dirac operator: In this lecture we argue that the fluctuations of Dirac eigenvalues on the\nfinest scale, i.e. on the scale of the average level spacing do not depend on\nthe underlying dynamics and can be obtained from a chiral random matrix theory\nwith the same low energy effective theory. We present three pieces of evidence\nsupporting that such microscopic correlations of lattice QCD Dirac spectra are\ngiven by chiral random matrix theory. First, we find that the spectral\ncorrelations of eigenvalues in the bulk of the spectrum obey the\nDyson-Mehta-Wigner statistics. Second, we show that the valence quark mass\ndependence for sufficiently small quark masses, as calculated by the Columbia\ngroup, can be obtained from the microscopic spectral density of chiral random\nmatrix theory. Third, in the framework of chiral random matrix models, we\npresent results showing that the microscopic spectral density is strongly\nuniversal, i.e. is insensitive to the details of the probability distribution."
    },
    {
        "anchor": "Diffusion Models as Stochastic Quantization in Lattice Field Theory: In this work, we establish a direct connection between generative diffusion\nmodels (DMs) and stochastic quantization (SQ). The DM is realized by\napproximating the reversal of a stochastic process dictated by the Langevin\nequation, generating samples from a prior distribution to effectively mimic the\ntarget distribution. Using numerical simulations, we demonstrate that the DM\ncan serve as a global sampler for generating quantum lattice field\nconfigurations in two-dimensional $\\phi^4$ theory. We demonstrate that DMs can\nnotably reduce autocorrelation times in the Markov chain, especially in the\ncritical region where standard Markov Chain Monte-Carlo (MCMC) algorithms\nexperience critical slowing down. The findings can potentially inspire further\nadvancements in lattice field theory simulations, in particular in cases where\nit is expensive to generate large ensembles.",
        "positive": "Phase of the Fermion Determinant for QCD at Finite Chemical Potential: In this lecture we discuss various properties of the phase factor of the\nfermion determinant for QCD at nonzero chemical potential. Its effect on\nphysical observables is elucidated by comparing the phase diagram of QCD and\nphase quenched QCD and by illustrating the failure of the Banks-Casher formula\nwith the example of one-dimensional QCD. The average phase factor and the\ndistribution of the phase are calculated to one-loop order in chiral\nperturbation theory. In quantitative agreement with lattice QCD results, we\nfind that the distribution is Gaussian with a width $\\sim \\mu T \\sqrt V$ (for\n$m_\\pi \\ll T \\ll \\Lambda_{\\rm QCD}$). Finally, we introduce, so-called teflon\nplated observables which can be calculated accurately by Monte Carlo even\nthough the sign problem is severe."
    },
    {
        "anchor": "Topological Index Theorem on the Lattice through the Spectral Flow of\n  Staggered Fermions: We investigate numerically the spectral flow introduced by Adams for the\nstaggered Dirac operator on realistic (quenched) gauge configurations. We\nobtain clear numerical evidence that the definition works as expected: there is\na clear separation between crossings near and far away from the origin, and the\ntopological charge defined through the crossings near the origin agrees, for\nmost configurations, with the one defined through the near-zero modes of large\ntaste-singlet chirality of the staggered Dirac operator. The crossings are much\ncloser to the origin if we improve the Dirac operator used in the definition,\nand they move towards the origin as we decrease the lattice spacing.",
        "positive": "On chiral extrapolations of coupled-channel reaction dynamics for\n  charmed mesons: We perform an analysis of QCD lattice data on masses of charmed meson with\nJ^P = 0^- and J^P =1^- quantum numbers. The quark-mass dependence of the data\nset is used to gain information on the size of counter terms in the chiral\nLagrangian formulated with open-charm mesons. Of particular interest are those\ncounter terms that are active in the exotic flavour sextet channel. A chiral\nexpansion scheme is developed and applied to the lattice data set. An accurate\nreproduction of the lattice data based on ensembles of PACS-CS, MILC, ETMC and\nHSC with pion and kaon masses smaller than 600 MeV is achieved. It is argued\nthat a unique set of low-energy parameters is obtainable only if additional\ninformation from an HSC ensemble on some scattering phase shifts is included in\nour global fits. Based on such low-energy parameters we find a clear signal for\na member of the exotic flavour sextet states in the pi D phase shift, between\nthe eta D and bar K D_s thresholds. A striking dependence of such phase shifts\non the values of the up, down and strange quarks is predicted."
    },
    {
        "anchor": "$D \\rightarrow Kl\u03bd$ semileptonic decay using lattice QCD with HISQ\n  at physical pion masses: The quark flavor sector of the Standard Model is a fertile ground to look for\nnew physics effects through a unitarity test of the Cabbibo-Kobayashi-Maskawa\n(CKM) matrix. We present a lattice QCD calculation of the scalar and the vector\nform factors (over a large $q^2$ region including $q^2 = 0$) associated with\nthe $D \\rightarrow Kl{\\nu}$ semi-leptonic decay. This calculation will then\nallow us to determine the central CKM matrix element, $V_{cs}$ in the Standard\nModel, by comparing the lattice QCD results for the form factors and the\nexperimental decay rate. This form factor calculation has been performed on the\n$N_f =2+1+1$ MILC HISQ ensembles with the physical light quark masses.",
        "positive": "Testing Algorithms for Finite Temperature Lattice QCD: We discuss recent algorithmic improvements in simulating finite temperature\nQCD on a lattice. In particular, the Rational Hybrid Monte Carlo(RHMC)\nalgorithm is employed to generate lattice configurations for 2+1 flavor QCD.\nUnlike the Hybrid R Algorithm, RHMC is reversible, admitting a Metropolis\naccept/reject step that eliminates the $\\mathcal{O}(\\delta t^2)$ errors\ninherent in the R Algorithm. We also employ several algorithmic speed-ups,\nincluding multiple time scales, the use of a more efficient numerical\nintegrator, and Hasenbusch pre-conditioning of the fermion force."
    },
    {
        "anchor": "Aspects of gluon propagation in Landau gauge: spectral densities, and\n  mass scales at finite temperature: We discuss a method to extract the K\\\"all\\'en-Lehmann spectral density of a\nparticle (be it elementary or bound state) propagator and apply it to compute\ngluon spectral densities from lattice data. Furthermore, we also consider the\ninterpretation of the Landau-gauge gluon propagator at finite temperature as a\nmassive-type bosonic propagator.",
        "positive": "Chiral symmetry and spectral properties of the Dirac operator in G2\n  Yang-Mills Theory: We study spontaneous chiral symmetry breaking and the spectral properties of\nthe staggered lattice Dirac operator using quenched gauge configurations for\nthe exceptional group G2, which has a trivial center. In particular we study\nthe system below and above the finite temperature transition and use the\ntemporal boundary conditions of the fermions to probe the system. We evaluate\nseveral observables: The spectral density at the origin, the spectral gap, the\nchiral condensate and the recently proposed dual chiral condensate. We show\nthat chiral symmetry is broken at low temperatures and is restored at high\ntemperatures at the thermodynamic phase transition. Concerning the role of the\nboundary conditions we establish that in all respects the spectral quantities\nbehave for G2 in exactly the same way as for SU(N), when for the latter group\nthe gauge ensemble above T_c is restricted to the sector of configurations with\nreal Polyakov loop."
    },
    {
        "anchor": "Excited Baryons in Lattice QCD: We present first results for the masses of positive and negative parity\nexcited baryons calculated in lattice QCD using an O(a^2)-improved gluon action\nand a fat-link irrelevant clover (FLIC) fermion action in which only the\nirrelevant operators are constructed with APE-smeared links. The results are in\nagreement with earlier calculations of N^* resonances using improved actions\nand exhibit a clear mass splitting between the nucleon and its chiral partner.\nAn correlation matrix analysis reveals two low-lying J^P=(1/2)^- states with a\nsmall mass splitting. The study of different Lambda interpolating fields\nsuggests a similar splitting between the lowest two Lambda1/2^- octet states.\nHowever, the empirical mass suppression of the Lambda^*(1405) is not evident in\nthese quenched QCD simulations, suggesting a potentially important role for the\nmeson cloud of the Lambda^*(1405) and/or a need for more exotic interpolating\nfields.",
        "positive": "Perturbative analysis of twisted volume reduced theories: We discuss the perturbative expansion of SU(N) Yang-Mills theories defined on\na d-dimensional torus of linear size l with twisted boundary conditions,\ngeneralizing previous results in the literature. For a specific class of twist\ntensors depending on a single integer flux value k, we show that perturbative\nresults to all orders depend on the combination lN^(2/d) and a flux-dependent\nangle theta. This implies a new kind of volume independence that holds at\nfinite N and for fixed values of theta. Our results also provide interesting\ninformation about the possible occurrence of tachyonic instabilities at\none-loop order. We support the prescription that instabilities are avoided, if\nthe large N limit is taken keeping theta > theta_c, and appropriately scaling\nthe magnetic flux k with N. Numerical results in 2+1 dimensions provide a test\nof how these ideas extend into the non-perturbative regime."
    },
    {
        "anchor": "Static-light hadrons on a dynamical anisotropic lattice: We present preliminary results for the static-light meson and baryon spectra\nfor $N_f=2$ QCD. The study is performed on an anisotropic lattice and uses a\nnew all-to-all propagator method allowing us to determine particle masses to a\nhigh precision.",
        "positive": "Radiative transitions of doubly charmed baryons in lattice QCD: We evaluate the spin-$3/2 \\to$ spin-$1/2$ electromagnetic transitions of the\ndoubly charmed baryons on 2+1 flavor, $32^3 \\times 64$ PACS-CS lattices with a\npion mass of $156(9)$ MeV/c$^2$. A relativistic heavy quark action is employed\nto minimize the associated systematic errors on charm-quark observables. We\nextract the magnetic dipole, $M1$, and the electric quadrupole, $E2$,\ntransition form factors. In order to make a reliable estimate of the $M1$ form\nfactor, we carry out an analysis by including the effect of excited-state\ncontributions. We find that the $M1$ transition is dominant and light degrees\nof freedom ($u/d$- or $s$-quark) play the leading role. $E2$ form factors, on\nthe other hand, are found to be negligibly small, which in turn, have minimal\neffect on the helicity and transition amplitudes. We predict the decay widths\nand lifetimes of $\\Xi_{cc}^{\\ast +,++}$ and $\\Omega_{cc}^{\\ast +}$ based on our\nresults. Finite size effects on these ensembles are expected to be around 1\\%.\nDifferences in kinematical and dynamical factors with respect to the\n$N\\gamma\\to\\Delta$ transition are discussed and compared to non-lattice\ndeterminations as well keeping possible systematic artifacts in mind. A\ncomparison to $\\Omega_c \\gamma \\rightarrow \\Omega_c^\\ast$ transition and a\ndiscussion on systematic errors related to the choice of heavy quark action are\nalso given. Results we present here are particularly suggestive for\nexperimental facilities such as LHCb, PANDA, Belle II and BESIII to search for\nfurther states."
    },
    {
        "anchor": "Renormalization and topological susceptibility on the lattice: SU(2)\n  Yang-Mills theory: The renormalization functions involved in the determination of the\ntopological susceptibility in the SU(2) lattice gauge theory are extracted by\ndirect measurements, without relying on perturbation theory. The determination\nexploits the phenomenon of critical slowing down to allow the separation of\nperturbative and non-perturbative effects. The results are in good agreement\nwith perturbative computations.",
        "positive": "Finite density QCD phase transition in the heavy quark region: We extend our previous study of the QCD phase structure in the heavy quark\nregion to non-zero chemical potentials. To identify the critical point where\nthe first order deconfining transition terminates, we study an effective\npotential defined by the probability distribution function of the plaquette and\nthe Polyakov loop. The reweighting technique is shown to be powerful in\nevaluating the effective potential in a wide range of the plaquette and\nPolyakov loop expectation values. We adopt the cumulant expansion to overcome\nthe sign problem in the calculation of complex phase of the quark determinant.\nWe find that the method provides us with an intuitive and powerful way to study\nthe phase structure. We estimate the location of the critical point at finite\nchemical potential in the heavy quark region."
    },
    {
        "anchor": "Less naive about supersymmetric lattice quantum mechanics: We explain why naive discretization results that have appeared in\n[hep-lat/0006013] do not appear to yield the desired continuum limit. The\nfermion propagator on the lattice inevitably yields a diagram with nonvanishing\nUV degree D=0 contribution in lattice perturbation theory, in contrast to what\noccurs in the continuum. This diagram gives a finite correction to the boson\n2-point function that must be subtracted off in order to obtain the\nperturbation series of the continuum theory, in the limit where the lattice\nspacing $a$ vanishes. Using a transfer matrix approach, we provide a\nnonperturbative proof that this counterterm suffices to yield the desired\ncontinuum limit. This analysis also allows us to improve the action to O(a). We\ndemonstrate by Monte Carlo simulation that the spectrum of the continuum theory\nis well-approximated at finite but small $a$, for both weak and strong\ncoupling. We contrast the above situation for the naive lattice action to what\noccurs for the supersymmetric lattice action, which preserves a discrete\nversion of half the supersymmetry. There, cancellations between D=0 diagrams\noccur, obviating the need for counterterms.",
        "positive": "Properties of the approximate Yang-Mills ground-state wave functional in\n  2+1 dimensions: We review properties and lattice evidence in support of the recently proposed\ntemporal-gauge Yang-Mills vacuum wave functional in 2+1 dimensions."
    },
    {
        "anchor": "The phase structure of a chirally invariant lattice Higgs-Yukawa model\n  for small and for large values of the Yukawa coupling constant: We consider a chirally invariant lattice Higgs-Yukawa model based on the\nNeuberger overlap operator. As a first step towards the eventual determination\nof Higgs mass bounds we study the phase diagram of the model analytically in\nthe large Nf-limit. We present an expression for the effective potential at\ntree-level in the regime of small Yukawa and quartic coupling constants and\ndetermine the order of the phase transitions. In the case of strong Yukawa\ncouplings the model effectively becomes an O(4)-symmetric non-linear\nsigma-model for all values of the quartic coupling constant. This leads to the\nexistence of a symmetric phase also in the regime of large values of the Yukawa\ncoupling constant. On finite and small lattices, however, strong finite volume\neffects prevent the expectation value of the Higgs field from vanishing thus\nobscuring the existence of the symmetric phase at strong Yukawa couplings.",
        "positive": "A Possible Aoki Phase for Staggered Fermions: The phase diagram for staggered fermions is discussed in the context of the\nstaggered chiral Lagrangian, extending previous work on the subject. When the\ndiscretization errors are significant, there may be an Aoki-like phase for\nstaggered fermions, where the remnant SO(4) taste symmetry is broken down to\nSO(3). We solve explicitly for the mass spectrum in the 3-flavor degenerate\nmass case and discuss qualitatively the 2+1-flavor case. From numerical results\nwe find that current simulations are outside the staggered Aoki phase. As for\nnear-future simulations with more improved versions of the staggered action, it\nseems unlikely that these will be in the Aoki phase for any realistic value of\nthe quark mass, although the evidence is not conclusive."
    },
    {
        "anchor": "Thirring model at finite density in 2+1 dimensions with stochastic\n  quantization: We consider a generalization of the Thirring model in 2+1 dimensions at\nfinite density. We employ stochastic quantization and check for the\napplicability in the finite density case to circumvent the sign problem. To\nthis end we derive analytical results in the heavy dense limit and compare with\nnumerical ones obtained from a complex Langevin evolution. Furthermore we make\nuse of indirect indicators to check for incorrect convergence of the underlying\ncomplex Langevin evolution. The method allows the numerical evaluation of\nobservables at arbitrary values of the chemical potential. We evaluate the\nresults and compare to the (0+1)-dimensional case.",
        "positive": "Three-Dimensional Integrable Models and Associated Tangle Invariants: In this paper we show that the Boltzmann weights of the three-dimensional\nBaxter-Bazhanov model give representations of the braid group, if some suitable\nspectral limits are taken. In the trigonometric case we classify all possible\nspectral limits which produce braid group representations. Furthermore we prove\nthat for some of them we get cyclotomic invariants of links and for others we\nobtain tangle invariants generalizing the cyclotomic ones."
    },
    {
        "anchor": "N=2 Wess-Zumino model on the d=2 Euclidean lattice: We examine the N=2 Wess-Zumino model defined on the $d=2$ Euclidean lattice\nin connection with a restoration of the Leibniz rule in the limit $a\\to0$ in\nperturbatively finite theory. We are interested in the difference between the\nWilson and Ginsparg-Wilson fermions and in the effects of extra interactions\nintroduced by an analysis of Nicolai mapping. As for the Wilson fermion, it\ninduces a linear divergence to individual tadpole diagrams in the limit\n$a\\to0$, which is absent in the Ginsparg-Wilson fermion. This divergence\nsuggests that a careful choice of lattice regularization is required in a\nreliable numerical simulation. As for the effects of the extra couplings\nintroduced by an analysis of Nicolai mapping, the extra couplings do not\ncompletely remedy the supersymmetry breaking in correlation functions induced\nby the failure of the Leibniz rule in perturbation theory, though those\ncouplings ensure the vanishing of vacuum energy arising from disconnected\ndiagrams. Supersymmetry in correlation functions is recovered in the limit\n$a\\to 0$ {\\em with or without} those extra couplings. In the context of lattice\ntheory, it may be properly said that supersymmetry does not improve ultraviolet\nproperties but rather it is well accommodated in theories with good ultraviolet\nproperties.",
        "positive": "Lattice Study of $U_{A}(1)$ Anomaly: The Role of QCD-Monopoles: We investigate the role of QCD-monopoles for the $U_{A}(1)$ anomaly in the\nmaximally abelian gauge within the SU(2) lattice gauge theory. The existence of\nthe strong correlation between instantons and QCD-monopoles in the abelian\ngauge was already shown by both analytic and numerical works including the\nMonte Carlo simulation. Their interrelation brings us a conjecture that the\npresence of QCD-monopoles plays a considerable role on the $U_{A}(1)$ anomaly.\nWe find an evidence for our conjecture on a determination of the fermionic zero\nmodes of the Dirac operator in both the ``monopole removed'' gauge\nconfiguration and the ``photon removed'' gauge configuration."
    },
    {
        "anchor": "Numerical analysis of fractional charge solutions on the torus: We study by numerical methods a particular kind of SU(N) Yang-Mills solutions\nof the Euclidean equations of motion which appear on the torus when twisted\nboundary conditions are imposed. These are instanton-like configurations with\nthe peculiarity of having fractional topological charge. We focus on those\nsolutions with minimal non-trivial action $S=8\\pi^2/\\N$ and extract their\nproperties in a few different cases, paying special attention to the $N \\to\n\\infty$ limit.",
        "positive": "Proton and neutron electromagnetic radii and magnetic moments from\n  lattice QCD: We present results for the electromagnetic form factors of the proton and\nneutron computed on the $(2 + 1)$-flavor Coordinated Lattice Simulations (CLS)\nensembles including both quark-connected and -disconnected contributions. The\n$Q^2$-, pion-mass, lattice-spacing, and finite-volume dependence of our form\nfactor data is fitted simultaneously to the expressions resulting from\ncovariant chiral perturbation theory including vector mesons amended by models\nfor lattice artefacts. From these fits, we determine the electric and magnetic\nradii and the magnetic moments of the proton and neutron, as well as the Zemach\nradius of the proton. To assess the influence of systematic effects, we average\nover various cuts in the pion mass and the momentum transfer, as well as over\ndifferent models for the lattice-spacing and finite-volume dependence, using\nweights derived from the Akaike Information Criterion (AIC)."
    },
    {
        "anchor": "On the study of inclusive semileptonic decays of $B_s$-meson from\n  lattice QCD: In this contribution we describe a recent study focused on the lattice\ncalculation of inclusive decay rates of heavy mesons. We show how the inclusive\ncalculation can be achieved starting from four-point lattice correlation\nfunctions normalised appropriately. The correlators used in this project come\nfrom gauge ensembles provided by the JLQCD and ETM collaborations. An essential\npoint of this method is the extraction of spectral densities from lattice\ncorrelators which is obtained using two of the most recent approaches in the\nliterature. Our results are in remarkable agreement with analytical predictions\nfrom the operator-product expansion. This study represents the first step\ntowards a full lattice QCD study of heavy mesons inclusive semileptonic decays.",
        "positive": "Heat-Kernel Approach to the Overlap Formalism: We present a new regularization method, for d dim (Euclidean) quantum field\ntheories in the continuum formalism, based on the domain wall configuration in\n(1+d) dim space-time. It is inspired by the recent progress in the chiral\nfermions on lattice. The wall \"height\" is given by 1/M, where M is a\nregularization mass parameter and appears as a (1+d) dim Dirac fermion mass.\nThe present approach gives a {\\it thermodynamic view} to the domain wall or the\noverlap formalism in the lattice field theory. We will show qualitative\ncorrespondence between the present continuum results and those of lattice. The\nextra dimension is regarded as the (inverse) {\\it temperature} t. The domains\nare defined by the {\\it directions} of the \"system evolvement\", not by the sign\nof M as in the original overlap formalism. We take the 4 dim QED and 2 dim\nchiral gauge theory as examples. Especially the consistent and covariant\nanomalies are correctly obtained."
    },
    {
        "anchor": "A hidden symmetry in the Standard Model: We found an additional symmetry hidden in the fermion and Higgs sectors of\nthe Standard Model. It is connected to the centers of the SU(3) and SU(2)\nsubgroups of the gauge group. A lattice regularization of the whole Standard\nModel is constructed that possesses this symmetry.",
        "positive": "A model of random center vortex lines in continuous 2+1-dimensional\n  space-time: A picture of confinement in QCD based on a condensate of thick vortices with\nfluxes in the center of the gauge group (center vortices) is studied. Previous\nconcrete model realizations of this picture utilized a hypercubic space-time\nscaffolding, which, together with many advantages, also has some disadvantages,\ne.g., in the treatment of vortex topological charge. In the present work, we\nexplore a center vortex model which does not rely on such a scaffolding.\nVortices are represented by closed random lines in continuous 2+1-dimensional\nspace-time. These random lines are modeled as being piece-wise linear, and an\nensemble is generated by Monte Carlo methods. The physical space in which the\nvortex lines are defined is a torus with periodic boundary conditions. Besides\nmoving, growing and shrinking of the vortex configurations, also reconnections\nare allowed. Our ensemble therefore contains not a fixed, but a variable number\nof closed vortex lines. This is expected to be important for realizing the\ndeconfining phase transition. We study both vortex percolation and the\npotential V (R) between quark and anti-quark as a function of distance R at\ndifferent vortex densities, vortex segment lengths, reconnection conditions and\nat different temperatures. We find three deconfinement phase transitions, as a\nfunction of density, as a function of vortex segment length, and as a function\nof temperature."
    },
    {
        "anchor": "Updated tests of scaling and universality for the spin-spin correlations\n  in the 2D and 3D spin-S Ising models using high-temperature expansions: We have extended, from order 12 through order 25, the high-temperature series\nexpansions (in zero magnetic field) for the spin-spin correlations of the\nspin-S Ising models on the square, simple-cubic and body-centered-cubic\nlattices. On the basis of this large set of data, we confirm accurately the\nvalidity of the scaling and universality hypotheses by resuming several tests\nwhich involve the correlation function, its moments and the exponential or the\nsecond-moment correlation-lengths.",
        "positive": "Improvements to Nucleon Matrix Elements within a $\u03b8$ Vacuum from\n  Lattice QCD: Using the gradient flow, we calculated the nucleon mixing angle $\\alpha_{N}$\nand the nucleon electric dipole moment (EDM) induced by the QCD $\\theta$-term.\nTo do so, we computed the topological charge, and the nucleon two-point and\nthree-point correlation functions. The purpose of these proceedings is to\nexplore how the topological charge density interacts with the nucleon\ninterpolation operators. By understanding this relation, we can try to suppress\nnoise contributions to the $\\alpha_{N}$ and EDM signals by selecting specific\nregions where the signal dominates.\n  Using gauge fields provided by PACS-CS at $N_{f}=2+1$, a first collection of\nensembles were selected at a fixed lattice spacing $a=0.0907$ fm\n($\\beta=1.90$), fixed dimensions $32^{3}\\times 64$ and varying\n$m_{\\pi}\\approx\\lbrace 411,\\,570,\\,701\\rbrace$ MeV. A second collection was\nselected at fixed $m_{\\pi}\\approx701$ MeV, fixed box size of $L\\approx1.9$ fm\nand varying $a=\\lbrace 0.1215,\\,0.0980,\\,0.0685\\rbrace $ fm."
    },
    {
        "anchor": "Heavy and Light Quarks with Lattice Chiral Fermions: The feasibility of using lattice chiral fermions which are free of $O(a)$\nerrors for both the heavy and light quarks is examined. The fact that the\neffective quark propagators in these fermions have the same form as that in the\ncontinuum with the quark mass being only an additive parameter to a chirally\nsymmetric antihermitian Dirac operator is highlighted. This implies that there\nis no distinction between the heavy and light quarks and no mass dependent\ntuning of the action or operators as long as the discretization error $O(m^2\na^2)$ is negligible. Using the overlap fermion, we find that the $O(m^2a^2)$\n(and $O(ma^2)$) errors in the dispersion relations of the pseudoscalar and\nvector mesons and the renormalization of the axial-vector current and scalar\ndensity are small. This suggests that the applicable range of $ma$ may be\nextended to $\\sim 0.56$ with only 5% error, which is a factor of $\\sim 2.4$\nlarger than that of the improved Wilson action. We show that the generalized\nGell-Mann-Oakes-Renner relation with unequal masses can be utilized to\ndetermine the finite $ma$ errors in the renormalization of the matrix elements\nfor the heavy-light decay constants and semileptonic decay constants of the B/D\nmeson.",
        "positive": "Infrared Behaviour of SU(2) Gauge Theory with $N_f$ fundamental flavours: We review our recent results on the infrared behaviour of the SU(2) gauge\ntheory with $N_f$ massless fundamental flavour fermions. We have analyzed the\nrunning of the coupling in SU(2) gauge theories with six and eight fermionic\nflavours using the gradient flow step scaling method. From the running of the\ncoupling, we see a clear indication of an infrared stable fixed point in\ntheories with six and eight flavours. These results are confirmed by our mass\nspectrum study, where we varied the number of flavours from two to six. We also\ncompute the anomalous dimensions of mass and coupling."
    },
    {
        "anchor": "Magnetization and pressures at nonzero magnetic fields in QCD: Two approaches are pursued to determine the magnetization of the QCD vacuum\nat zero and nonzero temperatures using lattice simulations. The first method\nbuilds on pressure anisotropies which are induced by the magnetic field on the\nlattice. The second approach is a novel, generalized version of the integral\nmethod, which exploits the independence of the theory on B for asymptotically\nlarge quark masses. Both approaches give consistent results and confirm that\nthe QCD medium is paramagnetic. Finally, an interesting relation between QCD\nparamagnetism, magnetic catalysis of the QCD condensate and the QED\nbeta-function is pointed out.",
        "positive": "Heavy Quark Effective Theory at one-loop order: An explicit example: We consider correlation functions containing the axial current of one light\nand one heavy quark in the static approximation as well as in full QCD, using\nthe lattice regularization. Up to one-loop order of perturbation theory, we\nstudy the difference between the full and the effective theory in the continuum\nlimit. In the full theory we find a term non-analytic in 1/m, revealing the\nasymptotic character of the 1/m-expansion. In general, deviations from the\nm-to-infinity limit turn out to be small and are well described by the first\nnon-trivial terms when m is a factor 2-3 above the external scale. We also\ninvestigate the mass dependence of discretization errors, and find that the\nbehaviour of the correlation functions at finite lattice spacing differs\nsignificantly from that in the continuum limit when the quark mass is large."
    },
    {
        "anchor": "Light Hadron Masses on Coarse Lattices with Improved Actions: The lattice QCD field is currently undergoing a revolution in the manner in\nwhich improvements of the approach are being implemented. We are examining the\nutility of order-a^2-improved tadpole-improved actions for the light fermion\nsector. The masses of the low-lying hadrons are calculated using the\norder-a^2-improved gluon action and the order-a^2-improved 2-link fermion\naction of Hamber and Wu with further tadpole improvement. Initial results on a\n6^3 x 12 lattice at beta = 6.25 and a 10^3 x 16 lattice at beta = 7.0 are\npresented. The corresponding lattice spacings are approximately 0.40 fm and\n0.24 fm respectively. These lattices provide a constant volume in which the\nscaling of observables is assessed.",
        "positive": "Chern-Simons Diffusion Rate near the Electroweak Phase Transition for\n  $m_H \\approx m_W$: The rate of $B$-violation in the standard model at finite temperature is\nclosely related to the diffusion rate $\\Gamma$ of Chern-Simons number. We\ncompute this rate for $m_H \\approx m_W$ in the classical approximation in an\neffective SU(2)-Higgs model, using Krasnitz's algorithm. The parameters in the\neffective hamiltonian are determined by comparison with dimensional reduction.\nIn the high temperature phase we find $\\Gamma/V (\\alpha_W T)^4 \\approx 1$,\nneglecting a finite renormalization. In the low temperature phase near the\ntransition we find the rate to be much larger than might be expected from\nprevious analytic calculations based on the sphaleron."
    },
    {
        "anchor": "SU(3) quark-antiquark QCD flux tube: We compute the quark-antiquark flux tube for pure gauge SU(3) in space-time 3\n+ 1 dimensions. To increase the signal over noise ratio, we apply the improved\nmultihit and extended smearing techniques. We fit the field densities with an\nappropriate ansatz and we observe both the screening of the color fields and\nthe quantum widening of the flux tube in the mediator plane and in the charge\nplanes.",
        "positive": "The MIXMAX random number generator: In this note, we give a practical solution to the problem of determining the\nmaximal period of matrix generators of pseudo-random numbers which are based on\nan integer-valued unimodular matrix of size NxN known as MIXMAX and arithmetic\ndefined on a Galois field GF[p] with large prime modulus p. The existing theory\nof Galois finite fields is adapted to the present case, and necessary and\nsufficient condition to attain the maximum period is formulated. Three\nefficient algorithms are presented. First, allowing to compute the\nmultiplication by the MIXMAX matrix with O(N) operations. Second, to\nrecursively compute the characteristic polynomial with O(N^2) operations, and\nthird, to apply skips of large number of steps S to the sequence in O(N^2\nlog(S)) operations. It is demonstrated that the dynamical properties of this\ngenerator dramatically improve with the size of the matrix N, as compared to\nthe classes of generators based on sparse matrices and/or sparse characteristic\npolynomials. Finally, we present the implementation details of the generator\nand the results of rigorous statistical testing."
    },
    {
        "anchor": "Supersymmetric lattices: Discretization of supersymmetric theories is an old problem in lattice field\ntheory. It has resisted solution until quite recently when new ideas drawn from\norbifold constructions and topological field theory have been brought to bear\non the question. The result has been the creation of a new class of lattice\ngauge theory in which the lattice action is invariant under one or more\nsupersymmetries. The resultant theories are local and free of doublers and in\nthe case of Yang-Mills theories also possess exact gauge invariance. In\nprinciple they form the basis for a truly non-perturbative definition of the\ncontinuum supersymmetric field theory. In this talk these ideas are reviewed\nwith particular emphasis being placed on ${\\cal N}=4$ super Yang-Mills theory.",
        "positive": "Gauge Theory Couplings on Anisotropic Lattices: The advantage of simulating lattice field theory with quantum computers is\nhamstrung by the limited resources that induce large errors from finite volume\nand sizable lattice spacings. Previous work has shown how classical simulations\nnear the Hamiltonian limit can be used for setting the lattice spacings in\nreal-time through analytical continuation, thereby reducing errors in quantum\nsimulations. In this work, we derive perturbative relations between bare and\nrenormalized quantities in Euclidean spacetime at any anisotropy factor -- the\nratio of spatial to temporal lattice spacings -- and in any spatial dimension\nfor $U(N)$ and $SU(N)$. This reduces the required classical preprocessing for\nquantum simulations. We find less than $10\\%$ discrepancy between our\nperturbative results and those from existing nonperturbative determinations of\nthe anisotropy for $SU(2)$ and $U(1)$ gauge theories. For the discrete groups\n$\\mathbb{Z}_{10}$, $\\mathbb{Z}_{100}$ and $\\mathbb{BI}$, we perform lattice\nMonte Carlo simulations to extract anisotropy factors and observe similar\nagreement with our perturbative results."
    },
    {
        "anchor": "Towards the spectrum of low-lying particles in supersymmetric Yang-Mills\n  theory: We present the current results of our simulations of N=1 supersymmetric\nYang-Mills theory on a lattice. The masses of the gluino-glue particle, the\na-eta-prime, the a-f0 meson, and the scalar glueball are obtained at finer\nlattice spacing than before, and extrapolations towards vanishing gluino mass\nare made. The calculations employ different levels of stout smearing. The\nstatistical accuracy as well as the control of finite size effects and lattice\nartefacts are better than in previous investigations. Taking the statistical\nand systematic uncertainties into account, the extrapolations towards vanishing\ngluino mass of the masses of the fermionic and bosonic states in our present\ncalculations are consistent with the formation of degenerate supermultiplets.",
        "positive": "Instabilities and Non-Reversibility of Molecular Dynamics Trajectories: The theoretical justification of the Hybrid Monte Carlo algorithm depends\nupon the molecular dynamics trajectories within it being exactly reversible. If\ncomputations were carried out with exact arithmetic then it would be easy to\nensure such reversibility, but the use of approximate floating point arithmetic\ninevitably introduces violations of reversibility. In the absence of evidence\nto the contrary, we are usually prepared to accept that such rounding errors\ncan be made small enough to be innocuous, but in certain circumstances they are\nexponentially amplified and lead to blatantly erroneous results. We show that\nthere are two types of instability of the molecular dynamics trajectories which\nlead to this behavior, instabilities due to insufficiently accurate numerical\nintegration of Hamilton's equations, and intrinsic chaos in the underlying\ncontinuous fictitious time equations of motion themselves. We analyze the\nformer for free field theory, and show that it is essentially a finite volume\neffect. For the latter we propose a hypothesis as to how the Liapunov exponent\ndescribing the chaotic behavior of the fictitious time equations of motion for\nan asymptotically free quantum field theory behaves as the system is taken to\nits continuum limit, and explain why this means that instabilities in molecular\ndynamics trajectories are not a significant problem for Hybrid Monte Carlo\ncomputations. We present data for pure $SU(3)$ gauge theory and for QCD with\ndynamical fermions on small lattices to illustrate and confirm some of our\nresults."
    },
    {
        "anchor": "Lattice Simulations and Infrared Conformality: We examine several recent lattice-simulation data sets, asking whether they\nare consistent with infrared conformality. We observe, in particular, that for\nan SU(3) gauge theory with 12 Dirac fermions in the fundamental representation,\nrecent simulation data can be described assuming infrared conformality. Lattice\nsimulations include a fermion mass m which is then extrapolated to zero, and we\nnote that this data can be fit by a small-m expansion, allowing a controlled\nextrapolation. We also note that the conformal hypothesis does not work well\nfor two theories that are known or expected to be confining and chirally\nbroken, and that it does work well for another theory expected to be infrared\nconformal.",
        "positive": "Continuum limit in abelian projected SU(2) lattice gauge theory: We study the continuum limit of the abelian string tension and the density of\nabelian monopoles calculated after carefully fixing the maximal abelian gauge\nby employing the simulated annealing algorithm. We present the evidence that\nthe abelian string tension converges to the nonabelian one in the continuum\nlimit. For the monopole density we confirm earlier findings that the density of\nthe properly defined infrared monopoles has correct scaling while the total\ndensity seems divergent in the continuum limit due to ultraviolate\ncontributions. We also compare with results obtained with the usual iterative\ngauge fixing algorithm."
    },
    {
        "anchor": "Charged particles interaction in both a finite volume and a uniform\n  magnetic field: A formalism for describing charged particles interaction in both a finite\nvolume and a uniform magnetic field is presented. In the case of short-range\ninteraction between charged particles, we show that the factorization between\nshort-range physics and finite volume long-range correlation effect is\npossible, a L\\\"uscher formula-like quantization condition is thus obtained.",
        "positive": "Calculating the hadronic vacuum polarization and leading hadronic\n  contribution to the muon anomalous magnetic moment with improved staggered\n  quarks: We present a lattice calculation of the hadronic vacuum polarization and the\nlowest-order hadronic contribution to the muon anomalous magnetic moment, a_\\mu\n= (g-2)/2, using 2+1 flavors of improved staggered fermions. A precise fit to\nthe low-q^2 region of the vacuum polarization is necessary to accurately\nextract the muon g-2. To obtain this fit, we use staggered chiral perturbation\ntheory, including the vector particles as resonances, and compare these to\npolynomial fits to the lattice data. We discuss the fit results and associated\nsystematic uncertainties, paying particular attention to the relative\ncontributions of the pions and vector mesons. Using a single lattice spacing\nensemble (a=0.086 fm), light quark masses as small as roughly one-tenth the\nstrange quark mass, and volumes as large as (3.4 fm)^3, we find a_\\mu^{HLO} =\n(713 \\pm 15) \\times 10^{-10} and (748 \\pm 21) \\times 10^{-10} where the error\nis statistical only and the two values correspond to linear and quadratic\nextrapolations in the light quark mass, respectively. Considering systematic\nuncertainties not eliminated in this study, we view this as agreement with the\ncurrent best calculations using the experimental cross section for e^+e^-\nannihilation to hadrons, 692.4 (5.9) (2.4)\\times 10^{-10}, and including the\nexperimental decay rate of the tau lepton to hadrons, 711.0 (5.0)\n(0.8)(2.8)\\times 10^{-10}. We discuss several ways to improve the current\nlattice calculation."
    },
    {
        "anchor": "f_B and the Heavy-light Spectrum from NRQCD: The present status of lattice calculations of the B spectrum and f_B, using\nNRQCD for the b quark, is discussed.",
        "positive": "The CKM Lattice Working Group initiative: We present the CKM-LWG, a collection of working groups whose aim is to\ncompile world averages of lattice results relevant for high-energy\nphenomenology."
    },
    {
        "anchor": "Cellular automata and self-organized criticality: Cellular automata provide a fascinating class of dynamical systems capable of\ndiverse complex behavior. These include simplified models for many phenomena\nseen in nature. Among other things, they provide insight into self-organized\ncriticality, wherein dissipative systems naturally drive themselves to a\ncritical state with important phenomena occurring over a wide range of length\nand time scales.",
        "positive": "A new proposal for the fermion doubling problem: In this paper I propose the use of a lattice derivative operator that is\nequivalent to the ideal SLAC derivative operator in all lattice calculations,\nbut without the prohibitively expensive computational cost of the latter. A\npedagogical motivation and derivation of the closed form of the SLAC derivative\nin position space is presented, and the proposed method for its cost-effective\nimplementation is presented in detail."
    },
    {
        "anchor": "Implementation of Symanzik's Improvement Program for Simulations of\n  Dynamical Wilson Fermions in Lattice QCD: We discuss the implementation of a Sheikholeslami-Wohlert term for\nsimulations of lattice QCD with dynamical Wilson fermions as required by\nSymanzik's improvement program. We show that for the Hybrid Monte Carlo or\nKramers equation algorithm standard even-odd preconditioning can be maintained.\nWe design tests of the implementation using analytically and numerically\ncomputed cumulant expansions. We find that, for situations where the average\nnumber of Conjugate Gradient iterations exceeds 200, the overhead is only about\n20%.",
        "positive": "Quark confinement in the Yang-Mills theory with a gauge-invariant gluon\n  mass in view of the gauge-invariant BEH mechanism: In order to clarify the mechanism of quark confinement in the Yang-Mills\ntheory with mass gap, we propose to investigate the massive Yang-Mills model,\nnamely, Yang-Mills theory with ``a gauge-invariant gluon mass term'', which is\nto be deduced from a specific gauge-scalar model with a single radially-fixed\nscalar field under a suitable constraint called the reduction condition. The\ngluon mass term simulates the dynamically generated mass to be extracted in the\nlow-energy effective theory of the Yang-Mills theory and plays the role of a\nnew probe to study the phase structure and confinement mechanism.\n  In this talk, we first explain why such a gauge-scalar model is constructed\nwithout breaking the gauge symmetry through the gauge-independent description\nof the Brout-Englert-Higgs mechanism which does not rely on the spontaneous\nbreaking of gauge symmetry. Then we discuss how the numerical simulations for\nthe proposed massive Yang-Mills theory can be performed by taking into account\nthe reduction condition in the complementary gauge-scalar model on a lattice.\nBy using the reweighting method, we have investigated the effect of the gluon\nmass term to the Wilson loop (the static potential) and the dynamically\ngenerated mass. Moreover, we point out that the adjoint case would gives an\nalternative understanding for the physical meaning of the gauge-covariant\ndecomposition for the Yang-Mills field known as the Cho-Duan-Ge-Faddeev-Niemi\ndecomposition, while the fundamental case would give a novel decomposition\nwhich has been overlooked so far."
    },
    {
        "anchor": "Lattice QCD calculation of $D_s^{*}$ radiative decay using the 2+1\n  Wilson Clover fermion: We perform a lattice calculation on the radiative decay of $D_s^*$ using the\n2+1 Wilson Clover gauge ensembles generated by CLQCD collaboration. The\nradiative transition $D_s^*\\rightarrow D_s\\gamma$ and Dalitz decay\n$D_s^*\\rightarrow D_s e^+e^-$ are studied respectively. After a continuum\nextrapolation using three lattice spacings, we obtain $\\Gamma(D_s^*\\rightarrow\nD_s \\gamma)=0.0549(54)$ keV, which is consistent with previous lattice\ncalculations but with much improved precision. The Dalitz decay rate is also\ncalculated for the first time and the ratio with the radiative transition is\nfound to be $R_{ee}=0.624(3)\\%$. A total decay width of $D_s^*$ can then be\ndetermined as 0.0587(54) keV taking into account the experimental branching\nfraction. Combining with the most recent experimental measurement on the\nbranching fraction of the purely leptonic decay $D_s^{+,*}\\rightarrow\ne^+\\nu_e$, we obtain\n$f_{D_s^*}|V_{cs}|=(190.5^{+55.1}_{-41.7_{\\textrm{stat.}}}\\pm\n12.6_{\\textrm{syst.}})$ MeV, with a significantly improved systematic\nuncertainty compared to $42.7_{\\textrm{syst.}}$ obtained using previous lattice\nprediction of total decay width $0.070(28)$ keV as input.",
        "positive": "Lipatov Pomeron and the Heisenberg chain: It is pointed out that the recently discovered analogy between the QCD\ndescription of the Pomeron exchange and the Heisenberg chain may allow to apply\nlattice techniques to the high energy phenomena."
    },
    {
        "anchor": "The QCD String Spectrum and Conformal Field Theory: The low energy excitation spectrum of the critical Wilson surface is\ndiscussed between the roughening transition and the continuum limit of lattice\nQCD. The fine structure of the spectrum is interpreted within the framework of\ntwo-dimensional conformal field theory.",
        "positive": "Sizes of Lightest Glueballs in SU(3) Lattice Gauge Theory: Standard Monte Carlo simulations have been performed on improved lattices to\nmeasure the wave functions and sizes of the scalar and tensor glueballs at four\nlattice spacings in the range $a= 0.05 - 0.145$ fm. Systematic errors from\ndiscretization and finite volume are studied. Our results in the continuum\nlimit show that the size of the tensor state is approximately two times as\nlarge as that of the scalar glueball."
    },
    {
        "anchor": "Calorons and monopoles from smeared SU(2) lattice fields at non-zero\n  temperature: In equilibrium, at finite temperature below and above the deconfining phase\ntransition, we have generated lattice SU(2) gauge fields and have exposed them\nto smearing in order to investigate the emerging clusters of topological\ncharge. Analysing in addition the monopole clusters according to the maximally\nAbelian gauge, we have been able to characterize part of the topological\nclusters to correspond either to non-static calorons or static dyons in the\ncontext of Kraan-van Baal caloron solutions with non-trivial holonomy. We show\nthat the relative abundance of these calorons and dyons is changing with\ntemperature and offer an interpretation as dissociation of calorons into dyons\nwith increasing temperature. The profile of the Polyakov loop inside the\ntopological clusters and the (model-dependent) accumulated topological cluster\ncharges support this interpretation. Above the deconfining phase transition\nlight dyons (according to Kraan-van Baal caloron solutions with almost trivial\nholonomy) become the most abundant topological objects. They are presumably\nresponsible for the magnetic confinement in the deconfined phase.",
        "positive": "Anomalous transport with overlap fermions: Anomalous correlators of vector and axial currents which enter the Kubo\nformulae for the chiral magnetic and the chiral separation conductivities are\nexplicitly calculated for free overlap fermions on the lattice. The results are\nconfronted with continuum calculations in the finite-temperature\nregularization, and a subtle point of such regularization for chiral magnetic\nconductivity related to the correct counting of the chiral states is\nhighlighted. In agreement with some previous claims in the literature, we find\nthat in a lattice regularization which respects gauge invariance, the chiral\nmagnetic conductivity vanishes. We point out that the relation of anomalous\ntransport coefficients to axial anomaly is nontrivial due to the\nnon-commutativity of their infrared limit and the Taylor expansion in baryon or\nchiral chemical potential. In particular, we argue that the vector and axial\nWard identities fix the asymptotic behavior of anomalous current-current\ncorrelators in the limit of large momenta. Basing on the work of Knecht et al.\non the perturbative non-renormalization of the transverse part of the\ncorrelator of two vector and one axial currents, we demonstrate that the\nrelation of the anomalous vector-vector correlator to axial anomaly holds\nperturbatively in massless QCD but might be subject to non-perturbative\ncorrections. Finally, we identify kinematical regimes in which the anomalous\ntransport coefficients can be extracted from lattice measurements."
    },
    {
        "anchor": "The pion_0 to gamma gamma decay and the chiral anomaly in the\n  quark-composites approach to QCD: We evaluate the pion_0 into two gammas decay amplitude by an effective action\nderived from QCD in the quark composites approach, getting the standard value.\nWe also verify that our effective action correctly reproduces the chiral\nanomaly.",
        "positive": "Monte Carlo study of Schwinger model without the sign problem: Monte Carlo study of the Schwinger model (quantum electrodynamics in one\nspatial dimension) with a topological $\\theta$ term is very difficult due to\nthe sign problem in the conventional lattice formulation. In this paper, we\npoint out that this problem can be circumvented by utilizing the lattice\nformulation of the bosonized Schwinger model, initially invented by Bender et\nal. in 1985. After conducting a detailed review of their lattice formulation,\nwe explicitly validate its correctness through detailed comparisons with\nanalytical and previous numerical results at $\\theta = 0$. We also obtain the\n$\\theta$ dependence of the chiral condensate and successfully reproduce the\nmass perturbation result for small fermion masses $m / g \\lesssim 0.125$. As an\napplication, we perform a precise calculation of the string tension and\nquantitatively reveal the confining properties in the Schwigner model at finite\ntemperature and $\\theta$ region for the first time. In particular, we find that\nthe string tension is negative for noninteger probe charges around $\\theta =\n\\pi$ at low temperatures."
    },
    {
        "anchor": "Gluon chains and the quark-antiquark potential: The flux tube between a quark and an antiquark in Coulomb gauge is imagined\nin the gluon-chain model as a sequence of constituent gluons bound together by\nCoulombic nearest-neighbor interactions. We diagonalize the transfer matrix in\nSU(2) lattice gauge theory in a finite basis of states containing a static\nquark-antiquark pair together with zero, one, and two gluons in Coulomb gauge.\nWe show that while the string tension of the color-Coulomb potential (obtained\nfrom the zero-gluon to zero-gluon element of the transfer matrix) overshoots\nthe true asymptotic string tension by a factor of about three, the inclusion of\na few states with constituent gluons reduces the discrepancy considerably. The\nminimal energy eigenstate of the transfer matrix in the zero-, one-, and\ntwo-gluon basis exhibits a linearly rising potential with the string tension\nonly about 1.4 times larger than the asymptotic one.",
        "positive": "Flattening of the quantum effective potential in fermionic theories: We present methods to constrain fermionic condensates on the level of the\npath integral, which grant access to the quantum effective potential in the\ninfinite volume limit. In the case of a spontaneously broken symmetry, this\npotential possesses a manifestly flat region, which is inaccessible to the\nstandard approach on the lattice. However, by constraining the appropriate\norder parameters such as the chiral condensate, one is then able to probe the\nflat region. We demonstrate our method of constraining fermionic condensates in\nthe 2-dimensional Gross-Neveu model, which exhibits a spontaneously broken\nchiral symmetry. We show how the potential flattens for increasing volume and\nthat the flat region is dominated by inhomogeneous field configurations."
    },
    {
        "anchor": "Chiral Fermions on the Lattice: A recently proposed method for regularizing chiral gauge theories\nnon-perturbatively is discussed in detail. The result is an effective action\nwhich can be computed from the lattice gauge field, and which is suited for\nnumerical simulations.",
        "positive": "Centre Vortex Structure of QCD-Vacuum Fields and Confinement: The non-trivial ground-state vacuum fields of QCD form the foundation of\nmatter. Using modern visualisation techniques, this presentation examines the\nmicroscopic structure of these fields. Of particular interest are the centre\nvortices identified within the ground-state fields of lattice QCD. Our current\nfocus is on understanding the manner in which dynamical fermions in the QCD\nvacuum alter the centre-vortex structure. The impact of dynamical fermions is\nsignificant and provides new insights into the role of centre vortices in\nunderpinning both confinement and dynamical chiral symmetry breaking in QCD."
    },
    {
        "anchor": "Order a improved renormalization constants: We impose the axial and vector Ward identities on local fermion bilinear\noperators in the Sheikholesalami-Wohlert discretization of fermions. From this\nwe obtain all the coefficients needed to improve the theory at O(a), as well as\nthe scale and scheme independent renormalization constants, Z_A, Z_V and\nZ_S/Z_P.",
        "positive": "Symmetric Partitioned Runge-Kutta Methods for Differential Equations on\n  Lie Groups: In this paper, we develop a higher order symmetric partitioned Runge-Kutta\nmethod for a coupled system of differential equations on Lie groups. We start\nwith a discussion on partitioned Runge-Kutta methods on Lie groups of arbitrary\norder. As symmetry is not met for higher orders, we generalize the method to a\nsymmetric partitioned Runge-Kutta (SPRK) scheme. Furthermore, we derive a set\nof coefficients for convergence order 4. The SPRK integration method can be\nused, for example, in simulations of quantum field theories. Finally, we\ncompare the new SPRK scheme numerically with the St\\\"ormer-Verlet scheme, one\nof the state-of-the-art schemes used in this subject."
    },
    {
        "anchor": "Current matrix element in HAL QCD's wave function equivalent potential\n  method: We give a formula to calculate a matrix element of a conserved current in the\neffective quantum mechanics defined by the wave function equivalent potentials\nproposed by HAL QCD collaboration. As a first step, a non-relativistic field\ntheory with two channel coupling is considered as the original theory, with\nwhich a wave function equivalent HAL QCD potential is obtained in a closed\nanalytic form. The external field method is used to derive the formula by\ndemanding that the result should agree with the original theory. With this\nformula, the matrix element is obtained by sandwiching the effective current\noperator between the left and the right eigen functions of the effective\nHamiltonian associated with the HAL QCD potential. In addition to the naive\none-body current, the effective current operator contains an additional\ntwo-body term emerging from the degrees of freedom which has been integrated\nout.",
        "positive": "Glueball Properties at Finite Temperature in SU(3) Anisotropic Lattice\n  QCD: The thermal properties of the glueballs are studied using SU(3) anisotropic\nlattice QCD with beta=6.25, the renormalized anisotropy xi=a_s/a_t=4 over the\nlattice of the size 20^3\\times N_t with N_t = 24, 26, 28, 30, 33, 34, 35, 36,\n37, 38, 40, 43, 45, 50, 72 at the quenched level. To construct a suitable\noperator on the lattice, we adopt the smearing method, and consider its\nphysical meaning in terms of the operator size. First, we construct the\ntemporal correlators G(t) for the 0^{++} and 2^{++} glueballs, using more than\n5,000 gauge configurations at each temperature. We then measure the pole-mass\nof the thermal glueballs from G(t). For the lowest 0^{++} glueball, we observe\na significant pole-mass reduction of about 300 MeV near T_c or m_G(T\\simeq T_c)\n\\simeq 0.8 m_G(T\\sim 0), while its size remains almost unchanged as rho(T)\n\\simeq 0.4fm. Finally, for completeness, as an attempt to take into account the\neffect of thermal width Gamma(T) at finite temperature, we perform a more\ngeneral new analysis of G(t) based on its spectral representation. By adopting\nthe Breit-Wigner form for the spectral function rho(omega), we perform the\nbest-fit analysis as a straightforward extension to the standard pole-mass\nanalysis. The result indicates a significant broadening of the peak as Gamma(T)\n\\sim 300 MeV as well as rather modest reduction of the peak center of about 100\nMeV near T_c for the lowest 0^{++} glueball. The temporal correlators of the\ncolor-singlet modes corresponding to these glueballs above T_c are also\ninvestigated."
    },
    {
        "anchor": "Entropy and the Approach to the Thermodynamic Limit in Three-Dimensional\n  Simplicial Gravity: We present numerical results supporting the existence of an exponential bound\nin the dynamical triangulation model of three-dimensional quantum gravity.Both\nthe critical coupling and various other quantities show a slow power law\napproach to the infinite volume limit.",
        "positive": "Dependence of the static quark free energy on $\u03bc_B$ and the crossover\n  temperature of $N_f = 2+1$ QCD: We study the dependence of the static quark free energy on the baryon\nchemical potential for $N_f = 2+1$ QCD with physical quark masses, in a range\nof temperature spanning from 120~MeV up to 1~GeV and adopting a stout staggered\ndiscretization with two different values of the Euclidean temporal extension,\n$N_t = 6$ and $N_t = 8$. In order to deal with the sign problem, we exploit\nboth Taylor expansion and analytic continuation, obtaining consistent results.\nWe show that the dependence of the free energy on $\\mu_B$ is sensitive to the\nlocation of the chiral crossover, in particular the $\\mu_B$-susceptibility,\ni.e. the linear term in $\\mu_B^2$ in the Taylor expansion of the free energy,\nhas a peak around 150 MeV. We also discuss the behavior expected in the high\ntemperature regime based on perturbation theory, and obtain a good quantitative\nagreement with numerical results."
    },
    {
        "anchor": "Phase structure and the gluon propagator of SU(2) gauge-Higgs model in\n  two dimensions: We study numerically the phase structure and the gluon propagator of the\nSU(2) gauge-Higgs model in two dimensions. First, we calculate gauge-invariant\nquantities, in particular the static potential from Wilson Loop, the W\npropagator, and the plaquette expectation value. Our results suggest that a\nconfinement-like region and a Higgs-like region appear even in two dimensions.\nIn the confinement-like region, the static potential rises linearly, with\nstring breaking at large distances, while in the Higgs-like region, it is of\nYukawa type, consistent with a Higgs-type mechanism. The correlation length\nobtained from the W propagator has a finite maximum between these regions. The\nplaquette expectation value shows a smooth cross-over consistent with the\nFradkin-Shenker-Osterwalder-Seiler theorem. From these results, we suggest that\nthere is no phase transition in two dimensions. We also calculate a\ngauge-dependent order parameter in Landau gauge. Unlike gauge invariant\nquantities, the gauge non-invariant order parameter has a line of discontinuity\nseparating these two regions. Finally we calculate the gluon propagtor. We\ninfer from its infrared behavior that the gluon propagator would vanish at zero\nmomentum in the infinite-volume limit, consistent with an analytical study.",
        "positive": "Inverse Monte-Carlo determination of effective lattice models for SU(3)\n  Yang-Mills theory at finite temperature: This paper concludes our efforts in describing SU(3)-Yang-Mills theories at\ndifferent couplings/temperatures in terms of effective Polyakov-loop models.\nThe associated effective couplings are determined through an inverse Monte\nCarlo procedure based on novel Schwinger-Dyson equations that employ the\nsymmetries of the Haar measure. Due to the first-order nature of the phase\ntransition we encounter a fine-tuning problem in reproducing the correct\nbehavior of the Polyakov-loop from the effective models. The problem remains\nunder control as long as the number of effective couplings is sufficiently\nsmall."
    },
    {
        "anchor": "The Wilson Dirac Spectrum for QCD with Dynamical Quarks: All microscopic correlation functions of the spectrum of the Hermitian Wilson\nDirac operator with any number of flavors with equal masses are computed. In\nparticular, we give explicit results for the spectral density in the physical\ncase with two light quark flavors. The results include the leading effect in\nthe discretization error and are given for fixed index of the Wilson Dirac\noperator. They have been obtained starting from chiral Lagrangians for the\ngenerating function of the Dirac spectrum. Microscopic correlation functions of\nthe real eigenvalues of the Wilson Dirac operator are computed following the\nsame approach.",
        "positive": "Phase structure of three flavor QCD in external magnetic fields using\n  HISQ fermions: We study the phase structure of QCD with three degenerate flavors in the\nexternal magnetic fields using highly improved staggered quarks (HISQ). The\nsimulations are performed on $16^3\\times 6$ lattice. In order to investigate\nthe quark mass dependence of the chiral transition we choose the values of the\nbare quark masses 0.015 and 0.0009375 in the lattice unit, corresponding to\n$m_\\pi=320$ MeV and 80 MeV in the continuum limit. We found no indication of a\nfirst order phase transition in the current window of quark masses and external\nmagnetic fields. Unlike to the case with standard staggered fermions inverse\nmagnetic catalysis is always observed at about the critical temperature. The\nmicroscopic origin of this phenomena are further discussed by looking into the\nDirac eigenvalue spectrum."
    },
    {
        "anchor": "Exploring the chiral regime of $N_f=2$ QCD with mixed actions: We report on our simulations with Neuberger valence fermions on CLS $N_f=2$\nconfigurations with non-perturbatively $O(a)$-improved Wilson sea quarks. We\nconsider the matching of QCD to ChPT in the so called mixed-regime in which the\nsea quarks are in the $p$-regime while the valence quarks are in the\n$\\epsilon$-regime. From this matching, we can get information on $\\Sigma$,\n$L_6$ and the combination $L_8+2L_6+2L_7$.",
        "positive": "SU(2) Lattice Gauge Theory at Nonzero Chemical Potential and Temperature: SU(2) lattice gauge theory with four flavors of quarks is simulated at\nnonzero chemical potential mu and temperature T and the results are compared to\nthe predictions of Effective Lagrangians. Simulations on 16^4 lattices indicate\nthat at zero T the theory experiences a second order phase transition to a\ndiquark condensate state which is well described by mean field theory. Nonzero\nT and mu are studied on 12^3 times 6 lattices. For low T, increasing mu takes\nthe system through a line of second order phase transitions to a diquark\ncondensed phase. Increasing T at high mu, the system passes through a line of\nfirst order transitions from the diquark phase to the quark-gluon plasma phase."
    },
    {
        "anchor": "Lattice study of the Coleman--Weinberg mass in the SU(2)-Higgs model: Radiative symmetry breaking is a well known phenomenon in perturbation\ntheory. We study the problem in a non-perturbative framework, i.e. lattice\nsimulations. The example of the bosonic sector of the SU(2)-Higgs model is\nconsidered. We determine the minimal scalar mass which turns out to be higher\nthan the mass value given by 1-loop continuum perturbation theory.",
        "positive": "Non-gauge fixing approach to chiral gauge theories using staggered\n  fermions: We investigate a proposal for the construction of models with chiral fermions\non the lattice using staggered fermions. In this approach the gauge invariance\nis broken by the coupling of the staggered fermions to the gauge fields.\nMotivated by previous results in the non-gauge invariant massive Yang-Mills\ntheory and certain gauge-fermion models we aim at a dynamical restoration of\nthe gauge invariance in the full quantum model. If the gauge symmetry breaking\nis not too severe, this procedure could lead in the continuum limit to the\ndesired gauge invariant chiral gauge theory. This scenario is very attractive\nsince it does not rely on gauge fixing. We investigate a simple realization of\nthis approach in a U(1) axial-vector model with dynamical fermions in four\ndimensions."
    },
    {
        "anchor": "$K\\to(\u03c0\u03c0)_{I=2}$ decays and twisted boundary conditions: We propose a new method to evaluate the Lellouch-L\\\"uscher factor which\nrelates the $\\Delta I=3/2$ $K\\to\\pi\\pi$ matrix elements computed on a finite\nlattice to the physical (infinite-volume) decay amplitudes. The method relies\non the use of partially twisted boundary conditions, which allow the s-wave\n$\\pi\\pi$ phase shift to be computed as an almost continuous function of the\ncentre-of-mass relative momentum and hence for its derivative to be evaluated.\nWe successfully demonstrate the feasibility of the technique in an exploratory\ncomputation.",
        "positive": "Electromagnetic Self-Duality in a Lattice Model: We formulate a Euclidean lattice theory of interacting elementary spin-half\nelectric and magnetic charges, which we refer to as electrons and magnetic\nmonopoles respectively. The model uses the polymer representation of the\nfermion determinant, and exhibits a self-dual symmetry provided electric charge\n$e$ and magnetic charge $g$ obey the minimal Dirac quantisation condition\n$eg=2\\pi$. In a hopping parameter expansion at lowest order, we show that\nvirtual electron and monopole loops contribute radiative corrections of\nopposite sign to the photon propagator. We argue that in the limit $e\\to0$,\nfermion mass $\\mu\\to0$, the model describes QED together with strongly\ninteracting monopoles whose chiral symmetry is spontaneously broken. Prospects\nfor the existence of an interacting continuum limit at the self-dual point\n$e=g$ are discussed."
    },
    {
        "anchor": "One spatial dimensional finite volume three-body interaction for a\n  short-range potential: In this work, we use McGuire's model to describe scattering of three spinless\nidentical particles in one spatial dimension, we first present analytic\nsolutions of Faddeev's equation for scattering of three spinless particles in\nfree space. The three particles interaction in finite volume is derived\nsubsequently, and the quantization conditions by matching wave functions in\nfree space and finite volume are presented in terms of two-body scattering\nphase shifts. The quantization conditions obtained in this work for short range\ninteraction are L\\\"uscher's formula like and consistent with Yang's results in\n\\cite{Yang:1967bm}.",
        "positive": "Locating analytically critical temperature in some statistical systems: We have found a simple criterion which allows for the straightforward\ndetermination of the order-disorder critical temperatures. The method\nreproduces exactly results known for the two dimensional Ising, Potts and\n$Z(N<5)$ models. It also works for the Ising model on the triangular lattice.\nFor systems which are not selfdual our proposition remains an unproven\nconjecture. It predicts $\\beta_c=0.2656...$ for the two coupled layers of Ising\nspins. Critical temperature of the three dimensional Ising model is related to\nthe free energy of the two layer Ising system."
    },
    {
        "anchor": "Fermion bags, duality and the three dimensional massless lattice\n  Thirring model: The recently proposed fermion bag approach is a powerful technique to solve\nsome four-fermion lattice field theories. Due to the existence of a duality\nbetween strong and weak couplings, the approach leads to efficient Monte Carlo\nalgorithms in both these limits. The new method allows us for the first time to\naccurately compute quantities close to the quantum critical point in the three\ndimensional lattice Thirring model with massless fermions on large lattices.\nThe critical exponents at the quantum critical point are found to be\n$\\nu=0.85(1)$, $\\eta = 0.65(1)$ and $\\eta_\\psi = 0.37(1)$.",
        "positive": "Anomaly Cancellation Condition in Abelian Lattice Gauge Theories: This paper has been withdrawn by the author."
    },
    {
        "anchor": "Color Flux Profiles in SU(2) Lattice Gauge Theory: Results of a high statistics study of chromo field distributions around\nstatic sources in pure SU(2) gauge theory on lattices of volumes $16^4$,\n$32^4$, and $48^3\\times 64$ at $\\beta=2.5$, $2.635$, and $2.74$ are presented.\nWe establish string formation up to physical distances as large as 2 fm.",
        "positive": "On the Nf and a Dependence of BK: We present results of a study of BK using tadpole improved gauge invariant\nstaggered operators. Using three ensembles of 16^3x32 configurations with\nvarying numbers of dynamical flavors, we observe a small dependence on Nf.\nUsing seven quenched ensembles between beta=5.7 and beta=6.2 we extrapolate to\na=0."
    },
    {
        "anchor": "Three dimensional finite temperature SU(3) gauge theory near the phase\n  transition: We have measured the correlation function of Polyakov loops on the lattice in\nthree dimensional SU(3) gauge theory near its finite temperature phase\ntransition. Using a new and powerful application of finite size scaling, we\nfurthermore extend the measurements of the critical couplings to considerably\nlarger values of the lattice sizes, both in the temperature and space\ndirections, than was investigated earlier in this theory. With the help of\nthese measurements we perform a detailed finite size scaling analysis, showing\nthat for the critical exponents of the two dimensional three state Potts model\nthe mass and the susceptibility fall on unique scaling curves. This strongly\nsupports the expectation that the gauge theory is in the same universality\nclass. The Nambu-Goto string model on the other hand predicts that the exponent\n\\nu has the mean field value, which is quite different from the value in the\nabovementioned Potts model. Using our values of the critical couplings we also\ndetermine the continuum limit of the value of the critical temperature in terms\nof the square root of the zero temperature string tension. This value is very\nnear to the prediction of the Nambu-Goto string model in spite of the different\ncritical behaviour.",
        "positive": "Ising Model Universality for Two-Dimensional Lattices: We use the single-cluster Monte Carlo update algorithm to simulate the Ising\nmodel on two-dimensional Poissonian random lattices of Delaunay type with up to\n80\\,000 sites. By applying reweighting techniques and finite-size scaling\nanalyses to time-series data near criticality, we obtain unambiguous support\nthat the critical exponents for the random lattice agree with the exactly known\nexponents for regular lattices, i.e., that (lattice) universality holds for the\ntwo-dimensional Ising model."
    },
    {
        "anchor": "Phase transitions in quantum chromodynamics: The current understanding of finite temperature phase transitions in QCD is\nreviewed. A critical discussion of refined phase transition criteria in\nnumerical lattice simulations and of analytical tools going beyond the\nmean-field level in effective continuum models for QCD is presented.\nTheoretical predictions about the order of the transitions are compared with\npossible experimental manifestations in heavy-ion collisions. Various places in\nphenomenological descriptions are pointed out, where more reliable data for\nQCD's equation of state would help in selecting the most realistic scenario\namong those proposed. Unanswered questions are raised about the relevance of\ncalculations which assume thermodynamic equilibrium. Promising new approaches\nto implement nonequilibrium aspects in the thermodynamics of heavy-ion\ncollisions are described.",
        "positive": "Non-Perturbative Fine-Tuning in Approximately Supersymmetric Models: We present two Fermi-Bose models with an approximate supersymmetry and which\ncan be solved with great accuracy using the renormalization group method. The\nbosonic parts of these models consist in Dyson's hierarchical model with one\nand two scalar components respectively. We discuss the question of the\nperturbative cancellation of divergences and compare with the non-perturbative\nfine-tunings necessary to keep the renormalized mass small in cut-off units. We\nshow evidence for non-perturbative cancellations of quantum corrections,\nhowever, we were not able to achieve exact cancellations without fine-tuning."
    },
    {
        "anchor": "Quenched Light Hadron Spectrum: We present results of a large-scale simulation for the flavor non-singlet\nlight hadron spectrum in quenched lattice QCD with the Wilson quark action.\nHadron masses are calculated at four values of lattice spacing in the range $a\n\\approx$ 0.1 - 0.05 fm on lattices with a physical extent of 3 fm at five quark\nmasses corresponding to $m_\\pi/m_\\rho \\approx 0.75$ - 0.4. The calculated\nspectrum in the continuum limit shows a systematic deviation from experiment,\nthough the magnitude of deviation is contained within 11%. Results for decay\nconstants and light quark masses are also reported.",
        "positive": "Precision Determination of Baryon Masses including Isospin-breaking: We give an update on an ongoing project in which we calculate the masses of\noctet and decuplet baryons including isospin-breaking effects. To this end, we\nemploy single- and two-state-fits to effective masses up to leading order in\nthe expansion in isospin-breaking parameters. In order to remove subjective\nbias on asymptotic masses we furthermore compute an AIC-based model-average of\nour fits, for which we show results on ensembles at lattice spacings of 0.064\nfm and 0.076 fm with corresponding pion masses ranging from 220 MeV to 360 MeV."
    },
    {
        "anchor": "Finite density QCD with a canonical approach: We present a canonical method where the properties of QCD are directly\nobtained as a function of the baryon density rho, rather than the chemical\npotential mu. We apply this method to the determination of the phase diagram of\nfour-flavor QCD. For a pion mass m_pi \\sim 350 MeV, the first-order transition\nbetween the hadronic and the plasma phase gives rise to a co-existence region\nin the T-rho plane, which we study in detail, including the associated\ninterface tension. We obtain accurate results for systems containing up to 30\nbaryons and quark chemical potentials mu up to 2 T. Our T-mu phase diagram\nagrees with the literature when mu/T \\lesssim 1. At larger chemical potential,\nwe observe a ``bending down'' of the phase boundary. We compare the free energy\nin the confined and deconfined phase with predictions from a hadron resonance\ngas and from a free massless quark gas respectively.",
        "positive": "How to Count Kinks: From the Continuum to the Lattice and Back: We investigate the matching between (1+1)-dimensional nonlinear field\ntheories coupled to an external stochastic environment and their lattice\nsimulations. In particular, we focus on how to obtain numerical results which\nare lattice-spacing independent, and on how to extract the correct effective\npotential which emerges from the simulations. As an application, we study the\nthermal production of kink-antikink pairs, obtaining a number density of pairs\nwhich is lattice-spacing independent and the effective barrier for pair\nproduction, i.e., the effective kink mass."
    },
    {
        "anchor": "Toward a novel determination of the strong QCD coupling at the Z-pole: We test here our recently introduced new lattice method for the\n$\\beta$-function defined over infinite Euclidean space-time in the continuum\nfrom scale changes generated by infinitesimal or finite steps of the\nrenormalized gauge coupling on the gradient flow. Harlander and Neumann\ncalculated in this scheme the three-loop approximation to the continuum\n$\\beta$-function. Our goal is the nonperturbative lattice implementation of the\nscheme which we tested originally in the chiral limit of the sextet model and\nin multi-flavor QCD with ten and twelve flavors of massless fermions. Results\nare reported here in the SU(3) Yang-Mills gauge sector without dynamical\nfermions and in ten-flavor QCD with massless femions. The three-loop gradient\nflow based $\\beta$-function of Harlander and Neumann is used to connect the\n$\\Lambda_{\\overline{\\rm MS}}$ scale of the SU(3) Yang-Mills gauge theory with\nthe nonperturbative flow time scale $t_0$, or the equivalent Sommer scale\n$r_0$. Similarly, the $\\Lambda_{\\overline{\\rm MS}}$ scale is connected with a\nselected nonperturbative scale in the ten-flavor theory, a pilot study of our\nnew lattice based nonperturbative $\\beta$-function for high precision\ndetermination of the strong coupling $\\alpha_s$ at the Z-boson pole in QCD with\nthree massless fermion flavors. This goal is an important alternative to\nresults from the finite volume based step $\\beta$-function of the Alpha\ncollaboration. Work is ongoing on direct application of the method to QCD with\nthree massless fermion flavors.",
        "positive": "Bottom spectroscopy on dynamical 2+1 flavor domain wall fermion lattices\n  with a relativistic heavy quark action: Following the successful application of the relativistic heavy quark(RHQ)\naction to the charmonium and charm-strange meson spectrum, we study here the\nbottom system to explore the validity of this method in a regime with larger\nheavy quark momenta. The spectrum is calculated using the same dynamical 2+1\nflavor, $24^3\\times 64$ domain wall fermion lattice configurations generated by\nthe RBC and UKQCD collaborations and used in the earlier charm study. The 3\nparameters in the RHQ action are determined by matching to the experimental\nbottom-strange meson masses and extrapolated to the chiral limit from three\ndifferent sea quark masses. We predict the bottomonium mass spectrum and\ncompare it with experiment. A theoretical estimation is also carried out to\nunderstand the $O(a^2p^2)$ systematic errors found in the numerical study."
    },
    {
        "anchor": "Staggered Chiral Perturbation Theory and the Fourth-Root Trick: Staggered chiral perturbation theory (schpt) takes into account the\n\"fourth-root trick\" for reducing unwanted (taste) degrees of freedom with\nstaggered quarks by multiplying the contribution of each sea quark loop by a\nfactor of 1/4. In the special case of four staggered fields (four flavors,\nnF=4), I show here that certain assumptions about analyticity and phase\nstructure imply the validity of this procedure for representing the rooting\ntrick in the chiral sector. I start from the observation that, when the four\nflavors are degenerate, the fourth root simply reduces nF=4 to nF=1. One can\nthen treat nondegenerate quark masses by expanding around the degenerate limit.\nWith additional assumptions on decoupling, the result can be extended to the\nmore interesting cases of nF=3, 2, or 1. A apparent paradox associated with the\none-flavor case is resolved. Coupled with some expected features of unrooted\nstaggered quarks in the continuum limit, in particular the restoration of taste\nsymmetry, schpt then implies that the fourth-root trick induces no problems\n(for example, a violation of unitarity that persists in the continuum limit) in\nthe lowest energy sector of staggered lattice QCD. It also says that the theory\nwith staggered valence quarks and rooted staggered sea quarks behaves like a\nsimple, partially-quenched theory, not like a \"mixed\" theory in which sea and\nvalence quarks have different lattice actions. In most cases, the assumptions\nmade in this paper are not only sufficient but also necessary for the validity\nof schpt, so that a variety of possible new routes for testing this validity\nare opened.",
        "positive": "Phase Structure of Four Dimensional Simplicial Quantum Gravity: We present the results of a high statistics Monte Carlo study of a model for\nfour dimensional euclidean quantum gravity based on summing over\ntriangulations. We show evidence for two phases; in one there is a logarithmic\nscaling on the mean linear extent with volume, whilst the other exhibits power\nlaw behaviour with exponent 1/2. We are able to extract a finite size scaling\nexponent governing the growth of the susceptibility peak"
    },
    {
        "anchor": "Towards precision heavy flavour physics from lattice QCD: I convey an idea of the significant recent progress, which opens up good\nperspectives for high-precision ab-initio computations in heavy flavour physics\nbased on lattice QCD. This report focuses on the strategy and the challenges of\nfully non-perturbative investigations in the B-meson sector, where the b-quark\nis treated within an effective theory, as followed by the ALPHA Collaboration.\nAs an application, I outline its use to determine the b-quark mass and\nsummarize the status of our ongoing project in the two dynamical flavour\ntheory.",
        "positive": "Strange quarks in quenched twisted mass lattice QCD: Two twisted doublets, one containing the up and down quarks and the other\ncontaining the strange quark with an SU(2)-flavor partner, are used for studies\nin the meson sector. The relevant chiral perturbation theory is presented, and\nquenched QCD simulations (where the partner of the strange quark is not active)\nare performed. Pseudoscalar meson masses and decay constants are computed; the\nvector and scalar mesons are also discussed. A comparison is made to the case\nof an untwisted strange quark, and some effects due to quenching,\ndiscretization, and the definition of maximal twist are explored."
    },
    {
        "anchor": "Phenomenology of a Composite Higgs Model: Several UV complete models of physics beyond the Standard Model are currently\nunder scrutiny, their low-energy dynamics being compared with the experimental\ndata from the LHC. Lattice simulations can play a role in these studies by\nproviding a first principles computations of the low-energy constants that\ndescribe this low-energy dynamics. In this work, we study in detail a specific\nmodel recently proposed by Ferretti, and discuss the potential impact of\nlattice calculations.",
        "positive": "$\u03b8$-dependence and center symmetry in Yang-Mills theories: We investigate the relation between the realization of center symmetry and\nthe dependence on the topological parameter $\\theta$ in $SU(N)$ Yang-Mills\ntheories, exploiting trace deformations as a tool to regulate center symmetry\nbreaking in a theory with a small compactified direction. We consider, in\nparticular, $SU(4)$ gauge theory, which admits two possible independent\ndeformations, and study, as a first step, its phase diagram in the deformation\nplane for two values of the inverse compactified radius going up to $L^{-1}\n\\sim 500$ MeV, comparing the predictions of the effective 1-loop potential of\nthe Polyakov loop with lattice results. The $\\theta$-dependence of the various\nphases is then addressed, up to the fourth order in $\\theta$, by numerical\nsimulations: results are found to coincide, within statistical errors, with\nthose of the standard confined phase iff center symmetry is completely restored\nand independently of the particular way this happens, i.e. either by local\nsuppression of the Polyakov loop traces or by long range disorder."
    },
    {
        "anchor": "Probing Nucleon Structure on the Lattice: The QCDSF/UKQCD collaboration has an ongoing program to calculate nucleon\nmatrix elements with two flavours of dynamical O(a) improved Wilson fermions.\nHere we present recent results on the electromagnetic form factors, the quark\nmomentum fraction <x> and the first three moments of the nucleon's\nspin-averaged and spin-dependent generalised parton distributions, including\npreliminary results with pion masses as low as 320 MeV.",
        "positive": "The equation of state in (2+1)-flavor QCD: We present results for the equation of state in (2+1)-flavor QCD using the\nhighly improved staggered quark action and lattices with temporal extent\n$N_{\\tau}=6,~8,~10$, and $12$. We show that these data can be reliably\nextrapolated to the continuum limit and obtain a number of thermodynamic\nquantities and the speed of sound in the temperature range $(130-400)$ MeV. We\ncompare our results with previous calculations, and provide an analytic\nparameterization of the pressure, from which other thermodynamic quantities can\nbe calculated, for use in phenomenology. We show that the energy density in the\ncrossover region, $145~ {\\rm MeV} \\leq T \\leq 163$ MeV, defined by the chiral\ntransition, is $\\epsilon_c=(0.18-0.5)~{\\rm GeV}/{\\rm fm}^3$, $i.e.$,\n$(1.2-3.1)\\ \\epsilon_{\\rm nuclear}$. At high temperatures, we compare our\nresults with resummed and dimensionally reduced perturbation theory\ncalculations. As a byproduct of our analyses, we obtain the values of the scale\nparameters $r_0$ from the static quark potential and $w_0$ from the gradient\nflow."
    },
    {
        "anchor": "Series studies of the Potts model. III: The 3-state model on the simple\n  cubic lattice: The finite lattice method of series expansion has been used to extend\nlow-temperature series for the partition function, order parameter and\nsusceptibility of the $3$-state Potts model on the simple cubic lattice to\norder $z^{43}$ and the high-temperature expansion of the partition function to\norder $v^{21}$. We use the numerical data to show that the transition is\nfirst-order, and estimate the latent heat, the discontinuity in the\nmagnetisation, and a number of other critical parameters.",
        "positive": "Status of the CP-PACS Project: The CP-PACS Project, which started in April 1992, is a five-year plan to\ndevelop a massively parallel computer for carrying out research in\ncomputational physics with primary emphasis on lattice QCD. This article\ndescribes the architectural design of the CP-PACS computer, the entire\ncomputing system including the front end and mass storage, and results of\nbenchmarks for the expected performance for lattice QCD applications."
    },
    {
        "anchor": "Chiral Effective Theory Methods and their Application to the Structure\n  of Hadrons from Lattice QCD: For many years chiral effective theory (ChEFT) has enabled and supported\nlattice QCD calculations of hadron observables by allowing systematic effects\nfrom unphysical lattice parameters to be controlled. In the modern era of\nprecision lattice simulations approaching the physical point, ChEFT techniques\nremain valuable tools. In this review we discuss the modern uses of ChEFT\napplied to lattice studies of hadron structure in the context of recent\ndeterminations of important and topical quantities. We consider muon g-2,\nstrangeness in the nucleon, the proton radius, nucleon polarizabilities, and\nsigma terms relevant to the prediction of dark-matter-hadron interaction\ncross-sections, among others.",
        "positive": "GW fermion propagators and chiral condensate: By exploiting the chiral symmetry, we derive analytic formulas for the\nmassless and the massive Ginsparg-Wilson fermion propagators. Using these\nformulas, we derive an expression for the chiral condensate which is the order\nparameter for spontaneous chiral symmetry breaking in QCD. These formulas\nprovide the proper way to compute the fermion propagators and may save a\nsignificant amount of computing time especially for large lattices in four\ndimensions."
    },
    {
        "anchor": "Monte Carlo simulations of a supersymmetric matrix model of dynamical\n  compactification in non perturbative string theory: The IKKT or IIB matrix model has been postulated to be a non perturbative\ndefinition of superstring theory. It has the attractive feature that spacetime\nis dynamically generated, which makes possible the scenario of dynamical\ncompactification of extra dimensions, which in the Euclidean model manifests by\nspontaneously breaking the SO(10) rotational invariance (SSB). In this work we\nstudy using Monte Carlo simulations the 6 dimensional version of the Euclidean\nIIB matrix model. Simulations are found to be plagued by a strong complex\naction problem and the factorization method is used for effective sampling and\ncomputing expectation values of the extent of spacetime in various dimensions.\nOur results are consistent with calculations using the Gaussian Expansion\nmethod which predict SSB to SO(3) symmetric vacua, a finite universal extent of\nthe compactified dimensions and finite spacetime volume.",
        "positive": "Lattice Formulation for 2d N=(2,2), (4,4) Super Yang-Mills Theories\n  without Admissibility Conditions: We present a lattice formulation for two-dimensional N=(2,2) and (4,4)\nsupersymmetric Yang-Mills theories that resolves vacuum degeneracy for gauge\nfields without imposing admissibility conditions. Cases of U(N) and SU(N) gauge\ngroups are considered, gauge fields are expressed by unitary link variables,\nand one or two supercharges are preserved on the two-dimensional square\nlattice. There does not appear fermion doubler, and no fine-tuning is required\nto obtain the desired continuum theories in a perturbative argument. This\nformulation is expected to serve as a more convenient basis for numerical\nsimulations. The same approach will also be useful to other two-dimensional\nsupersymmetric lattice gauge theories with unitary link variables constructed\nso far -- for example, N=(8,8) supersymmetric Yang-Mills theory and N=(2,2)\nsupersymmetric QCD."
    },
    {
        "anchor": "Deconfinement transitions in three-dimensional compact lattice Abelian\n  Higgs models with multiple-charge scalar fields: We investigate the nature of the deconfinement transitions in\nthree-dimensional lattice Abelian Higgs models, in which a complex scalar field\nof integer charge $Q\\ge 2$ is minimally coupled with a compact $U(1)$ gauge\nfield. Their phase diagram presents two phases separated by a transition line\nwhere static charges $q$, with $q<Q$, deconfine. We argue that these\ndeconfinement transitions belong to the same universality class as transitions\nin generic three-dimensional ${\\mathbb Z}_Q$ gauge models. In particular, they\nare Ising-like for $Q=2$, of first order for $Q=3$, and belong to the\nthree-dimensional gauge $XY$ universality class for $Q\\ge 4$. This general\nscenario is supported by numerical finite-size scaling analyses of the energy\ncumulants for $Q=2$, $Q=4$, and $Q=6$.",
        "positive": "Lost in Normalization: The consequences of the gauge-coupling dependent normalization-factor of\n$1/g^{\\alpha}$ in the transfer-matrix of 2d U(1) lattice gauge theory are\nexplored. It is seen by the $\\alpha=1$ choice that the lowest energy develops a\nminimum at coupling $g_*=1.125$, leading to a \\textit{multi-valued} Gibbs\nenergy similar to the systems with the first-order phase transition. It is\nargued how the $1/g$ normalization may be regarded as a lost normalization in\nthe commonly used change of variable to the dimensionless angle-variables.\nBased on the continuum limit at the next-leading order and the Ostrogradsky\nformulation of higher-order time-derivatives theories, it is argued that the\nspectrum at continuum is compatible only with the $\\alpha=1$ choice."
    },
    {
        "anchor": "A new algorithm for numerical simulation of Langevin equations: Formulated is a new systematic method for obtaining higher order corrections\nin numerical simulation of stochastic differential equations (SDEs), i.e.,\nLangevin equations. Random walk step algorithms within a given order of finite\n$\\Delta t$, are obtained so as to reproduce within that order a corresponding\ntransition density of the Fokker-Planck equations, in the weak Taylor\napproximation scheme. A great advantage of our method is its\nstraightforwardness such that direct perturbative calculations produce the\nalgorithm as an end result, so that the procedure is tractable by computer.\nExamples in general form for curved space cases as well as flat space cases are\ngiven in some order of approximations. Simulations are performed for specific\nexamples of U(1) system and SU(2) systems, respectively.",
        "positive": "QCD thermodynamics with two flavors of Wilson quarks at N_t=6: We report on a study of hadron thermodynamics with two flavors of Wilson\nquarks on 12^3x6 lattices. We have studied the crossover between the high and\nlow temperature regimes for three values of the hopping parameter, kappa=0.16,\n0.17, and 0.18. At each of these values of kappa we have carried out spectrum\ncalculations on 12^3x24 lattices for two values of the gauge coupling in the\nvicinity of the crossover in order to set an energy scale for our\nthermodynamics calculations and to determine the critical value of the gauge\ncoupling for which the pion and quark masses vanish. For kappa=0.17 and 0.18 we\nfind coexistence between the high and low temperature regimes over 1,000\nsimulation time units indicating either that the equilibration time is\nextremely long or that there is a possibility of a first order phase\ntransition. The pion mass is large at the crossover values of the gauge\ncoupling, but the crossover curve has moved closer to the critical curve along\nwhich the pion and quark masses vanish, than it was on lattices with four time\nslices. In addition, values of the dimensionless quantity T_c/m_rho are in\ncloser agreement with those for staggered quarks than was the case at N_t=4. (A\nPOSTSCRIPT VERSION OF THIS PAPER IS AVAILABLE BY ANONYMOUS FTP FROM\nsarek.physics.ucsb.edu (128.111.8.250) IN THE FILE pub/wilson_thermo.ps)"
    },
    {
        "anchor": "Lattice QCD study of the s-wave $\u03c0\u03c0$ scattering lengths in the I=0\n  and 2 channels: The s-wave pion-pion ($\\pi\\pi$) scattering lengths are computed below the\ninelastic threshold by the L\\\"uscher technique with pion masses ranging from\n240 MeV to 463 MeV. In the Asqtad-improved staggered fermion formulation, we\ncalculate the $\\pi\\pi$ four-point functions for the I=0 and 2 channels with\n\"moving\" wall sources without gauge fixing, and analyze them at the\nnext-to-leading order in the continuum three-flavor chiral perturbation theory.\nAt the physical pion mass, we secure the s-wave $\\pi\\pi$ scattering lengths as\n$m_\\pi a_{\\pi\\pi}^{I=0} = 0.214(4)(7)$ and $m_\\pi a_{\\pi\\pi}^{I=2} =\n-0.04430(25)(40)$ for the I=0 and 2 channels, respectively, where the first\nuncertainties are statistical and second ones are our estimates of several\nsystematic effects. Our lattice results for the s-wave $\\pi\\pi$ scattering\nlengths are in well accordance with available experimental reports and\ntheoretical forecasts at low momentum. A basic ingredient in our study for the\nI=0 case is properly incorporating disconnected diagram. These lattice\ncomputations are carried out with the MILC 2+1 flavor gauge configurations at\ntwo lattice spacings $a \\approx 0.15$ and 0.12 fm.",
        "positive": "Quenched Supersymmetry: We study the effects of quenching in Super-Yang-Mills theory. While\nsupersymmetry is broken, the lagrangian acquires a new flavour $U(1 \\mid 1)$\nsymmetry. The anomaly structure thus differs from the unquenched case. We\nderive the corresponding low-energy effective lagrangian. As a consequence, we\npredict the mass splitting expected in numerical simulations for particles\nbelonging to the lowest-lying supermultiplet."
    },
    {
        "anchor": "More on SU(3) Lattice Gauge Theory in the Fundamental--Adjoint Plane: We present further evidence for the bulk nature of the phase transition line\nin the fundamental--adjoint action plane of SU(3) lattice gauge theory.\nComputing the string tension and some glueball masses along the thermal phase\ntransition line of finite temperature systems with $N_t=4$, which was found to\njoin onto the bulk transition line at its endpoint, we find that the ratio\n$\\sqrt{\\sigma} / T_c$ remains approximately constant. However, the mass of the\n$0^{++}$ glueball decreases as the endpoint of the bulk transition line is\napproached, while the other glueball masses appear unchanged. This is\nconsistent with the notion that the bulk transition line ends in a critical\nendpoint with the continuum limit there being a $\\phi^4$ theory with a\ndiverging correlation length only in the $0^{++}$ channel.",
        "positive": "Lattice study of supersymmetry breaking in N=2 supersymmetric quantum\n  mechanics: We study supersymmetry breaking from a lattice model of N=2 supersymmetric\nquantum mechanics using the direct computational method proposed in\narXiv:1803.07960. The vanishing Witten index is realized as a numerical result\nin high precision. The expectation value of Hamiltonian is evaluated for the\ndouble-well potential. Compared with the previous Monte-Carlo results, the\nobtained vacuum energy coincides with the known values within small errors for\nstrong couplings. The instanton effect is also reproduced for weak couplings.\nThe used computational method helps us to evaluate the effect of finite lattice\nspacings more precisely and to study the mechanism of non-perturbative\nsupersymmetry breaking from lattice computations."
    },
    {
        "anchor": "Finite Temperature Lattice QCD with Clover Fermions: We report on our simulation of finite temperature lattice QCD with two\nflavors of ${\\cal O}(a)$ Symanzik-improved fermions and ${\\cal O}(a^2)$\nSymanzik-improved glue. Our thermodynamic simulations were performed on an $8^3\n\\times 4$ lattice, and we have performed complementary zero temperature\nsimulations on an $8^3 \\times 16$ lattice. We compare our results to those from\nsimulations with two flavors of Wilson fermions and discuss the improvement\nresulting from use of the improved action.",
        "positive": "Heavy quark masses from Fermilab Fermions: Using automated perturbation theory techniques, we have computed the one-loop\nmass of Fermilab fermions, with an improved gluon action. We will present the\nresults of these calculations, and the resulting predictions for the charm and\nbottom quark masses in the MSbar scheme. We report mc(mc) = 1:22(9) GeV and\nmb(mb) = 4:7(4) GeV. In addition we present results for the one-loop\ncoeffcients of the Fermilab action."
    },
    {
        "anchor": "Tackling critical slowing down using global correction steps with\n  equivariant flows: the case of the Schwinger model: We propose a new method for simulating lattice gauge theories in the presence\nof fermions. The method combines flow-based generative models for local gauge\nfield updates and hierarchical updates of the factorized fermion determinant.\nThe flow-based generative models are restricted to proposing updates to\ngauge-fields within subdomains, thus keeping training times moderate while\nincreasing the global volume. We apply our method performs to the 2-dimensional\n(2D) Schwinger model with $N_f=2$ Wilson Dirac fermions and show that no\ncritical slowing down is observed in the sampling of topological sectors up to\n$\\beta=8.45$. Furthermore, we show that fluctuations can be suppressed\nexponentially with the distance between active subdomains, allowing us to\nachieve acceptance rates of up to $99\\%$ for the outer-most accept/reject step\non lattices volumes of up to $V=128\\times128$.",
        "positive": "Progress report on the staggered epsilon'/epsilon project: We report on progress and future plans for calculating kaon weak matrix\nelements for epsilon'/epsilon using staggered fermions."
    },
    {
        "anchor": "Strongly coupled gauge theories towards physics beyond the Standard\n  Model: Strongly coupled gauge theories provide an ultra-violet realization of new\nphysics models for physics beyond the Standard Model of particle physics\narising from composite dynamics. Depending on the gauge group and matter\ncontent, they are expected to exhibit interesting features and rich\nphenomenology, similar or dissimilar to QCD, of which model builders and\nphenomenologists can take advantage. Due to the non-perturbative nature of\nthese theories, first principles lattice calculations are essential to test the\nvalidity of composite models and provide theoretical inputs, that are otherwise\nunattainable, to the experimental searches for new physics. In this\ncontribution, we will review recent efforts in the non-perturbative lattice\nstudies of strongly coupled gauge theories other than QCD in the context of\nphysics beyond the Standard Model by focusing on technical developments and new\nresults.",
        "positive": "Hybrid static potential flux tubes from SU(2) and SU(3) lattice gauge\n  theory: We compute chromoelectric and chromomagnetic flux densities for hybrid static\npotentials in SU(2) and SU(3) lattice gauge theory. In addition to the ordinary\nstatic potential with quantum numbers $\\Lambda_\\eta^\\epsilon = \\Sigma_g^+$, we\npresent numerical results for seven hybrid static potentials corresponding to\n$\\Lambda_\\eta^{(\\epsilon)} = \\Sigma_u^+, \\Sigma_g^-, \\Sigma_u^-, \\Pi_g, \\Pi_u,\n\\Delta_g, \\Delta_u$, where the flux densities of five of them are studied for\nthe first time in this work. We observe hybrid static potential flux tubes,\nwhich are significantly different from that of the ordinary static potential.\nThey are reminiscent of vibrating strings, with localized peaks in the flux\ndensities that can be interpreted as valence gluons."
    },
    {
        "anchor": "Topology at zero and finite T in SU(2) Yang-Mills theory: We determine the topological susceptibility \\chi at T=0 and its behaviour at\nfinite T across the deconfining transition in pure SU(2) gauge theory. We use\nan improved topological charge density operator. \\chi goes to zero above T_c,\nbut more slowly than in SU(3) gauge theory.",
        "positive": "Matrix product decomposition for two- and three-flavor Wilson fermions:\n  Benchmark results in the lattice Gross-Neveu model at finite density: We formulate the path integral of two- and three-flavor Wilson fermion in two\ndimensions as a multilayer Grassmann tensor network by the matrix product\ndecomposition. Thanks to this new description, the memory cost scaling is\nreduced from $\\mathrm{O}(\\mathrm{e}^{N_{f}})$ for the conventional construction\nto $\\mathrm{O}(N_{f})$. Based on this representation, we develop a\ncoarse-graining algorithm where spatially or temporally adjacent Grassmann\ntensors are converted into a canonical form along a virtual direction before we\ncarry out the spacetime coarse-graining. Benchmarking with the lattice\nGross-Neveu model at finite density, we see that the Silver Blaze phenomenon in\nthe pressure and number density is captured with relatively small bond\ndimensions."
    },
    {
        "anchor": "The quark propagator and quark-gluon vertex from lattice QCD at finite\n  temperature: The quark-gluon vertex is an important object of QCD. Studies have shown that\nthis quantity is relevant for the dynamical chiral symmetry breaking pattern in\nthe vacuum. The goal of our project is to obtain the quark-gluon vertex at\nfinite temperature around the deconfinement/chiral transition using the tools\nprovided by lattice QCD. It will be the first time that the quark-gluon vertex\nat finite temperature is determined using lattice QCD. The propagators, which\nare a by-product of this project, are also of interest in themselves. The\nconfigurations used were generated by the FASTSUM collaboration. In this\ncontribution, we describe our motivations and goals, some technical details of\nthe determination and report on the status of the calculation.",
        "positive": "A strong-coupling analysis of two-dimensional O(N) sigma models with\n  N<=2 on square, triangular and honeycomb lattices: The critical behavior of two-dimensional ${\\rm O}(N)$ $\\sigma$ models with\n$N\\leq 2$ on the square, triangular, and honeycomb lattices is investigated by\nan analysis of the strong-coupling expansion of the two-point fundamental\nGreen's function $G(x)$, calculated up to 21st order on the square lattice,\n15th order on the triangular lattice, and 30th order on the honeycomb lattice.\nFor $N<2$ the critical behavior is of power-law type, and the exponents\n$\\gamma$ and $\\nu$ extracted from our strong-coupling analysis confirm exact\nresults derived assuming universality with solvable solid-on-solid models. At\n$N=2$, i.e., for the 2-$d$ XY model, the results from all lattices considered\nare consistent with the Kosterlitz-Thouless exponential approach to\ncriticality, characterized by an exponent $\\sigma=1/2$, and with universality.\nThe value $\\sigma=1/2$ is confirmed within an uncertainty of few per cent. The\nprediction $\\eta=1/4$ is also roughly verified. For various values of $N\\leq\n2$, we determine some ratios of amplitudes concerning the two-point function\n$G(x)$ in the critical limit of the symmetric phase. This analysis shows that\nthe low-momentum behavior of $G(x)$ in the critical region is essentially\nGaussian at all values of $N\\leq 2$. New exact results for the long-distance\nbehavior of $G(x)$ when $N=1$ (Ising model in the strong-coupling phase)\nconfirm this statement."
    },
    {
        "anchor": "Determination of $B_K$ using improved staggered fermions (I): SU(3)\n  chiral perturbation theory fit: We present the results for $B_K$ calculated using HYP-smeared staggered\nfermions using lattices generated by the MILC collaboration using the asqtad\nstaggered action. We have done the calculation on 8 ensembles of these\nlattices, including three different lattice spacings ($a=0.12, 0.09, 0.06$ fm).\nWe fit the data to forms based on those predicted by SU(3) mixed-action\npartially-quenched staggered chiral perturbation theory. Our preliminary result\nis $ B_K(\\text{NDR},\\mu=2\\text{GeV}) = 0.528 \\pm 0.011 \\pm 0.048 $, where the\nfirst error is statistical and the second systematic. The error turns out to be\nlarger than that from an analysis using SU(2) chiral perturbation theory.",
        "positive": "Comparison of Monte Carlo Results for the 3D Ising Interface Tension and\n  Interface Energy with (Extrapolated) Series Expansions: We compare Monte Carlo results for the interface tension and interface energy\nof the 3-dimensional Ising model with Pad\\'e and inhomogeneous differential\napproximants of the low temperature series that was recently extended by Arisue\nto $17^{\\rm th}$ order in $u=\\exp(-4\\beta)$. The series is expected to suffer\nfrom the roughening singularity at $u\\approx 0.196$. The comparison with the\nMonte Carlo data shows that the Pad\\'e and inhomogeneous differential\napproximants fail to improve the truncated series result of the interface\ntension and the interface energy in the region around the roughening\ntransition. The Monte Carlo data show that the specific heat displays a peak in\nthe smooth phase. Neither the truncated series nor the Pad\\'e approximants find\nthis peak. We also compare Monte Carlo data for the energy of the ASOS model\nwith the corresponding low temperature series that we extended to order\n$u^{12}$."
    },
    {
        "anchor": "QCD Phases in Lattice QCD: I review the recent status of lattice QCD calculations at non-zero density.",
        "positive": "Gluon propagator and confinement scenario in Coulomb gauge: We present numerical results in SU(2) lattice gauge theory for the\ninstantaneous part of the gluon propagator in Coulomb gauge D_{44, inst} =\nV_{coul}(R) \\delta(t). Data are taken on lattice volumes 24^4 and 28^4 for 7\nvalues of beta in the interval $2.2 \\leq beta \\leq 2.8$. The data are\nconfronted with the confinement scenario in Coulomb gauge. They are consistent\nwith a linearly rising color-Coulomb potential V_{coul}(R)."
    },
    {
        "anchor": "Lattice study of the simplified model of M-theory: Lattice discretization of the supersymmetric Yang-Mills quantum mechanics is\nreviewed and results of the Monte Carlo simulations of the simplified model are\npresented. The D=4, N=2, quenched system, studied at finite temperature,\nreveals existence of the two distinct regions which may correspond to a black\nhole and the elementary 0-branes phases of the M-theory conjectured in the\nliterature. New results for higher gauge groups N < 9 lead to the similar\npicture, however the nature of the transition between the two phases and its\nprecise scaling with N is yet unresolved.",
        "positive": "Weak Matrix Elements on the Lattice: Recent Developments in K-Physics: Some recent developments in the calculation of weak matrix elements on the\nlattice are reviewed. In particular, we concentrate on the application of MPSTV\nnon-perturbative renormalization method to the operators relevant to kaon\nphysics. The chiral behaviour of the $B_K$ parameter and the long-standing\nquestion of the $\\Delta I=1/2$ rule are discussed."
    },
    {
        "anchor": "Brillouin improvement for Wilson fermions: We present a parameter-free Wilson-type lattice Dirac operator with an\n81-point stencil for the covariant derivative and the Laplacian which attempts\nto minimize the breaking of rotational symmetry near the boundary of the\nBrillouin zone. The usefulness of this \"Brillouin operator\" in practical\napplications is explored by studying the scaling of pseudoscalar decay\nconstants in quenched QCD, with rather good results in the physical charm\nregion. We also investigate the suitability of this operator as a kernel to the\noverlap procedure. Here, the resulting overlap operator is found to be cheaper\nto construct and significantly better localized than the variety with the\nstandard Wilson kernel.",
        "positive": "Excited state systematics in extracting nucleon electromagnetic form\n  factors: We present updated preliminary results for the nucleon electromagnetic form\nfactors for non-perturbatively $\\mathcal{O}(a)$ improved Wilson fermions in\n$N_f=2$ QCD measured on the CLS ensembles. The use of the summed operator\ninsertion method allows us to suppress the influence of excited states in our\nmeasurements. A study of the effect that excited state contaminations have on\nthe $Q^2$ dependence of the extracted nucleon form factors may then be made\nthrough comparisons of the summation method to standard plateau fits, as well\nas to excited state fits."
    },
    {
        "anchor": "Critical Higgs Mass and Temperature Dependence of Gauge Boson Masses in\n  the SU(2) Gauge-Higgs Model: We study the effective 3-D SU(2) Gauge-Higgs model at finite temperature for\nHiggs-masses in the range from $60$ GeV up to $100$ GeV. The first order\nelectroweak phase transition weakens with increasing Higgs-mass and terminates\nat a critical end-point. For Higgs-mass values larger than about\n$m_{H,c}=75.4(6)$ GeV the thermodynamic signature of the transition is\ndescribed by a crossover. Close to this Higgs-mass value we investigate the\nvector boson propagator in Landau gauge. The calculated W-boson screening\nmasses are compared with predictions based on gap equations.",
        "positive": "Nuclear Lattice Simulations with EFT: This proceedings article is a summary of results from work done in\ncollaboration with Bugra Borasoy and Thomas Schaefer. We study nuclear and\nneutron matter by combining chiral effective field theory with non-perturbative\nlattice methods. We present results for hot neutron matter at temperatures 20\nto 40 MeV and densities below twice nuclear matter density."
    },
    {
        "anchor": "Heavy monopole potential in gluodynamics: We discuss predictions for the interaction energy of the fundamental\nmonopoles in gluodynamics introduced via the 't Hooft loop. At short distances,\nthe heavy monopole potential is calculable from first principles. At larger\ndistances, we apply the Abelian dominance models. We discuss the measurements\nwhich would be crucial to distinguish between various models. Non-zero\ntemperatures are also considered. Our predictions are in qualitative agreement\nwith the existing lattice data. We discuss further measurements which would be\ncrucial to check the model.",
        "positive": "Transfer matrix for Kogut-Susskind fermions in the spin basis: In the absence of interaction it is well known that the Kogut-Susskind\nregularizations of fermions in the spin and flavor basis are equivalent to each\nother. In this paper we clarify the difference between the two formulations in\nthe presence of interaction with gauge fields. We then derive an explicit\nexpression of the transfer matrix in the spin basis by a unitary transformation\non that one in the flavor basis which is known. The essential key ingredient is\nthe explicit construction of the fermion Fock space for variables which live on\nblocks. Therefore the transfer matrix generates time translations of two\nlattice units."
    },
    {
        "anchor": "Partially Quenched Gauge Theories and a Application to Staggered\n  Fermions: We extend our lagrangian technique for chiral perturbation theory for\nquenched QCD to include theories in which only some of the quarks are quenched.\nWe discuss the relationship between the partially quenched theory and a theory\nin which only the unquenched quarks are present. We also investigate the\npeculiar infrared divergences associated with the $\\eta'$ in the quenched\napproximation, and find the conditions under which such divergences can appear\nin a partially quenched theory. We then apply our results to staggered fermion\nQCD in which the square root of the fermion determinant is taken, using the\nobservation that this should correspond to a theory with four quarks, two of\nwhich are quenched. [Uses harvmac macro package. No postscipt for the figures\nis available (sorry), but the figures are simple and we include do-it-yourself\ninstructions for drawing them.]",
        "positive": "Casimir scaling and renormalization of Polyakov loops in large-N gauge\n  theories: We study Casimir scaling and renormalization properties of Polyakov loops in\ndifferent irreducible representations in SU(N) gauge theories; in particular,\nwe investigate the approach to the large-N limit, by performing lattice\nsimulations of Yang-Mills theories with an increasing number of colors, from 2\nto 6. We consider the twelve lowest irreducible representations for each gauge\ngroup, and find strong numerical evidence for nearly perfect Casimir scaling of\nthe bare Polyakov loops in the deconfined phase. Then we discuss the\ntemperature dependence of renormalized loops, which is found to be\nqualitatively and quantitatively very similar for the various gauge groups. In\nparticular, close to the deconfinement transition, the renormalized Polyakov\nloop increases with the temperature, and its logarithm reveals a characteristic\ndependence on the inverse of the square of the temperature. At higher\ntemperatures, the renormalized Polyakov loop overshoots one, reaches a maximum,\nand then starts decreasing, in agreement with weak-coupling predictions. The\nimplications of these findings are discussed."
    },
    {
        "anchor": "On the reduction of hypercubic lattice artifacts: This note presents a comparative study of various options to reduce the\nerrors coming from the discretization of a Quantum Field Theory in a lattice\nwith hypercubic symmetry. We show that it is possible to perform an\nextrapolation towards the continuum which is able to eliminate systematically\nthe artifacts which break the O(4) symmetry.",
        "positive": "Tuning anisotropies for dynamical gauge configurations: We present methods and results for the tuning of quark and gluon anisotropies\nfor improved actions in N_f = 2 QCD."
    },
    {
        "anchor": "Where is the confining string in random percolation: The percolating phase of whatever random percolation process resembles the\nconfining vacuum of a gauge theory in most respects, with a string tension\nhaving a well-behaved continuum limit, a non trivial glueball spectrum and a\ndeconfinement transition at a well determined temperature T_c. Simple numerical\nexperiments reveal an underlying, strongly fluctuating, confining string, with\nan internal vortex structure formed by a core trapping inside a Coulomb-like\nphase composed by the vacuum at the percolation threshold. The width of the\ncore almost coincides with 1/T_c and it turns out to be separated form the\nconfining vacuum by a domain wall of definite thickness.",
        "positive": "In-Medium Modifications of Hadron Properties: The in-medium modifications of hadron properties are briefly discussed. We\nrestrict the discussion to the lattice QCD calculations for the hadron masses,\nscreening masses, decay constants and wave functions. We review the progress\nmade so far and describe how to broaden its horizon."
    },
    {
        "anchor": "The Ising Model on a Dynamically Triangulated Disk with a Boundary\n  Magnetic Field: We use Monte Carlo simulations to study a dynamically triangulated disk with\nIsing spins on the vertices and a boundary magnetic field. For the case of zero\nmagnetic field we show that the model possesses three phases. For one of these\nthe boundary length grows linearly with disk area, while the other two phases\nare characterized by a boundary whose size is on the order of the cut-off. A\nline of continuous magnetic transitions separates the two small boundary\nphases. We determine the critical exponents of the continuous magnetic phase\ntransition and relate them to predictions from continuum 2-d quantum gravity.\nThis line of continuous transitions appears to terminate on a line of\ndiscontinuous phase transitions dividing the small boundary phases from the\nlarge boundary phase. We examine the scaling of bulk magnetization and boundary\nmagnetization as a function of boundary magnetic field in the vicinity of this\ntricritical point.",
        "positive": "Independence on the Abelian Projection of Monopole Condensation in QCD: It is proven that dual superconductivity of QCD vacuum in the confining phase\nis an intinsic property, independent on the choice of the abelian projection\nused to define the monopoles."
    },
    {
        "anchor": "$\\langle x\\rangle$ and $\\langle x^2\\rangle$ of the pion PDF from Lattice\n  QCD with $N_f=2+1+1$ dynamical quark flavours: Using Nf=2+1+1 lattice QCD, we determine the fermionic connected\ncontributions to the second and third moment of the pion PDF. Based on gauge\nconfigurations from the European Twisted Mass Collaboration, chiral and\ncontinuum extrapolations are performed using pion masses in the range of 230 to\n500 MeV and three values of the lattice spacing. Finite volume effects are\ninvestigated using different volumes. In order to avoid mixing under\nrenormalisation for the third moment, we use an operator with two non-zero\nspatial components of momentum. Momenta are injected using twisted boundary\nconditions. Our final values read $\\langle x\\rangle=0.2075(106)$ and $\\langle\nx^2\\rangle=0.163(33)$, determined at 2 GeV in the $\\overline{MS}$-scheme and\nwith systematic and statistical uncertainties summend in quadrature.",
        "positive": "Numerical determination of partial spectrum of Hermitian matrices using\n  a Lanczos method with selective reorthogonalization: We introduce a new algorithm for finding the eigenvalues and eigenvectors of\nHermitian matrices within a specified region, based upon the LANSO algorithm of\nParlett and Scott. It uses selective reorthogonalization to avoid the\nduplication of eigenpairs in finite-precision arithmetic, but uses a new bound\nto decide when such reorthogonalization is required, and only reorthogonalizes\nwith respect to eigenpairs within the region of interest. We investigate its\nperformance for the Hermitian Wilson--Dirac operator (\\gamma_5D) in lattice\nquantum chromodynamics, and compare it with previous methods."
    },
    {
        "anchor": "Towards the large volume limit - A method for lattice QCD + QED\n  simulations: We present a method to couple finite-volume QCD to infinite-volume QED by an\nappropriate twist-averaging procedure. We demonstrate the prescription\nnumerically for the leading-order hadronic contribution to the anomalous\nmagnetic moment of the muon and the electro-magnetic pion mass splitting.",
        "positive": "(1+1)-dimensional Baryons from the SU(N) Color-Flavor Transformation: The color-flavor transformation, an identity that connects two integrals,\neach of which is over one of a dual pair of Lie groups acting in the fermionic\nFock space, is extended to the case of the special unitary group. Using this\nextension, a toy model of lattice QCD is studied: N_f species of spinless\nfermions interacting with strongly coupled SU(N_c) lattice gauge fields in 1+1\ndimensions. The color-flavor transformed theory is expressed in terms of gauge\nsinglets, the meson fields, organized into sectors distinguished by the\ndistribution of baryonic flux. A comprehensive analytical and numerical search\nis made for saddle-point configurations of the meson fields, with various\ntopological charges, in the vacuum and single-baryon sectors. Two definitions\nof the static baryon on the square lattice, straight and zigzag, are\ninvestigated. The masses of the baryonic states are estimated using the\nsaddle-point approximation for large N_c."
    },
    {
        "anchor": "QCD confronts heavy-flavor and exotic hadrons: A review of QCD-based theory approaches to study the heavy-flavor and exotic\nhadrons is given. The focus is on the results from lattice QCD and from lattice\nQCD complemented by effective field theories. Both approaches are first briefly\nintroduced and applied in few examples. Then the status of various hadrons\nsectors is presented.",
        "positive": "Numerical study of Yang-Mills classical solutions on the twisted torus: We use the lattice cooling method to investigate the structure of some gauge\nfixed SU(2) Yang-Mills classical solutions of the euclidean equations of motion\nwhich are defined in the 3-torus with symmetric twisted boundary conditions."
    },
    {
        "anchor": "Fermion-Higgs model with Reduced Staggered Fermions: We introduce a lattice fermion-Higgs model with one component `reduced\nstaggered' fermions. In order to use the fermion field as efficiently as\npossible we couple the two {\\em staggered} flavors to the O(4) Higgs field\nleading to a model with only one SU(2) doublet in the scaling region. The\nnumber of fermions is doubled in a numerical investigation of the model with\nthe hybrid Monte Carlo algorithm. We present results for the phase diagram,\nparticle masses and renormalized couplings on lattices ranging in size from\n$6^3 24$ to $16^3 24$.",
        "positive": "Lattice QCD at finite temperature: I discuss recent developments in finite temperature lattice QCD, including\nthe calculation of the transition temperature, equation of state, color\nscreening and meson spectral functions."
    },
    {
        "anchor": "Infinite Volume, Continuum Limit of Valence Approximation Hadron Masses: We obtain estimates of several hadron mass ratios, for Wilson quarks in the\nvalence (quenched) approximation, extrapolated to physical quark mass, infinite\nvolume and zero lattice spacing.",
        "positive": "A Study of PCAC for the Nonperturbative Improvement of the Wilson Action: We present an exploratory study for the nonperturbative determination of the\ncoefficient of the ${\\cal O}(a)$ improvement term to the Wilson action,\n$c_{SW}$. Following the work by L\\\"{u}scher et al., we impose the PCAC relation\nas a nonperturbative improvement condition on $c_{SW}$, without, however, using\nthe Schr\\\"{o}dinger functional in our calculation."
    },
    {
        "anchor": "Conformal window in SU(2) with fundamental fermions: We present the updated results of the infrared behavior of the SU(2) 6 and 8\nfundamental representation fermions. We use the gradient flow method with the\nSchr\\\"odinger functional boundary conditions to measure the running of the\ncoupling in these theories and find fixed points on both. We also measure the\nmass anomalous dimension from these configurations.",
        "positive": "Charmed baryon spectroscopy on the physical point in 2+1 flavor lattice\n  QCD: We investigate the charmed baryon mass spectrum using the relativistic heavy\nquark action on 2+1 flavor PACS-CS configurations previously generated on $32^3\n\\times 64$ lattice. The dynamical up-down and strange quark masses are set to\nthe physical values by using the technique of reweighting to shift the quark\nhopping parameters from the values employed in the configuration generation. At\nthe physical point, the lattice spacing equals $a^{-1}=2.194(10)$ GeV and the\nspatial extent $L=2.88(1)$ fm. Our results for the charmed baryon masses are\nconsistent with experiments except for $\\Xi_{cc}$, which has only weak\nexperimental evidence yet. We also predict mass values for other doubly and\ntriply charmed baryons."
    },
    {
        "anchor": "First-Order Phase Transition of the Schwinger Model with a Quantum\n  Computer: We explore the first-order phase transition in the lattice Schwinger model in\nthe presence of a topological $\\theta$-term by means of the variational quantum\neigensolver (VQE). Using two different fermion discretizations, Wilson and\nstaggered fermions, we develop parametric ansatz circuits suitable for both\ndiscretizations, and compare their performance by simulating classically an\nideal VQE optimization in the absence of noise. The states obtained by the\nclassical simulation are then prepared on the IBM's superconducting quantum\nhardware. Applying state-of-the art error-mitigation methods, we show that the\nelectric field density and particle number, observables which reveal the phase\nstructure of the model, can be reliably obtained from the quantum hardware. To\ninvestigate the minimum system sizes required for a continuum extrapolation, we\nstudy the continuum limit using matrix product states, and compare our results\nto continuum mass perturbation theory. We demonstrate that taking the additive\nmass renormalization into account is vital for enhancing the precision that can\nbe obtained with smaller system sizes. Furthermore, for the observables we\ninvestigate we observe universality, and both fermion discretizations produce\nthe same continuum limit.",
        "positive": "Composite Weak Bosons in a Confining Gauge Theory without Goldstone\n  Bosons: a Strong Coupling Expansion Analysis: We consider a confining Yang-Mills theory without Goldstone Bosons which\ncould describe the bosonic sector of the weak interactions. This model can be\ngauge invariantly regularized on a lattice. A strong coupling analysis of the\nlow lying bound state spectrum indicates that the vector isotriplet bound state\n(the right quantum number to represent the W-boson) could be the lightest state\nif the mass of the pseudoscalar isosinglet is raised sufficiently by the effect\nof the chiral anomaly (in analogy to the $\\eta'$ mechanism of QCD). This work\nis a preliminary study in support to an intensive lattice Monte Carlo analysis\nof the model."
    },
    {
        "anchor": "Matching lattice QC+ED to Nature: The first step of any QFT calculation, aiming at phenomenological\npredictions, is the matching of the theory to Nature. The matching procedure\nfixes the parameters of the theory in terms of an equal number of external\ninputs that, if the theory is expected to reproduce observations, must be\nexperimentally measured physical quantities. At the sub-percent level of\naccuracy QED radiative corrections become important and the theory expected to\ndescribe the hadronic Universe is QCD+QED. Phenomenological predictions\nderiving from lattice QCD calculations do depend, at this level of precision,\nupon the choice of the external inputs used to match/define the approximate\ntheory. In this written version of my talk I concentrate on the theoretical\naspects of the matching procedure of lattice QCD$+$QED and of the definition of\nQCD, strongly advocating a community agreement on the matching scheme to be\nused in future lattice QCD calculations.",
        "positive": "Relation between Confinement and Chiral Symmetry Breaking in Temporally\n  Odd-number Lattice QCD: In the lattice QCD formalism, we investigate the relation between confinement\nand chiral symmetry breaking. A gauge-invariant analytical relation connecting\nthe Polyakov loop and the Dirac modes is derived on a temporally odd-number\nlattice, where the temporal lattice size is odd, with the normal (nontwisted)\nperiodic boundary condition for link-variables. This analytical relation\nindicates that low-lying Dirac modes have little contribution to the Polyakov\nloop, and it is numerically confirmed at the quenched level in both confinement\nand deconfinement phases. This fact indicates no direct one-to-one\ncorrespondence between confinement and chiral symmetry breaking in QCD. Using\nthe relation, we also investigate the contribution from each Dirac mode to the\nPolyakov loop. In the confinement phase, we find a new \"positive/negative\nsymmetry\" of the Dirac-mode matrix element of the link-variable operator, and\nthis symmetry leads to the zero value of the Polyakov loop. In the\ndeconfinement phase, there is no such symmetry and the Polyakov loop is\nnonzero. Also, we develop a new method for spin-diagonalizing the Dirac\noperator on the temporally odd-number lattice modifying the Kogut-Susskind\nformalism."
    },
    {
        "anchor": "Infrared fixed point and anomalous dimensions in a composite Higgs model: We use lattice simulations and the continuous renormalization-group method,\nbased on the gradient flow, to study a candidate theory of composite Higgs and\na partially composite top. The model is an SU(4) gauge theory with four Dirac\nfermions in each of the fundamental and two-index antisymmetric\nrepresentations. We find that the theory has an infrared fixed point at $g^2\n\\simeq 15.5$ in the gradient flow scheme. The mass anomalous dimension of each\nrepresentation is large at the fixed point. On the other hand, the anomalous\ndimensions of top-partner operators do not exceed 0.5 at the fixed point. This\nmay not be large enough for a phenomenologically successful model of partial\ncompositeness.",
        "positive": "Variational calculation of heavy-light meson properties: We present a new method for the study of heavy-light mesons in the static\napproximation of lattice QCD which is optimally effective in isolating ground\nand excited states. With ``MOST'' (Maximal Operator Smearing Technique), the\nheavy quark is smeared at all possible positions relative to the light quark,\nsubject to the constraint of cubic symmetry. With correlation functions\nconstructed using this set as a variational basis, eigenstates of the transfer\nmatrix are projected out at very small time separations, where statistical\nerrors are small. We illustrate the utility of the method with preliminary\nresults for the meson decay constant $f_{B}^{\\rm stat}$, binding energies and\nwave functions of the lowest states. The method produces dynamically-improved\ninterpolating fields which can be used for matrix element calculations."
    },
    {
        "anchor": "Hadronic Parity-Violation on the Lattice: We motivate lattice QCD studies of the parity-violating pion-nucleon coupling\nconstant and extend flavor-conserving hadronic parity-violation from QCD to\npartially-quenched QCD. The parity-violating pion-nucleon coupling and the\nanapole form factor (and moment) of the proton are computed to one-loop order\nin the partially-quenched chiral expansion. For the parity-violating\npion-nucleon interaction, we include the contributions from total derivative\noperators necessary to match the kinematics that will be used in lattice\nsimulations.",
        "positive": "Confinement/deconfinement phase transition in SU(3) Yang-Mills theory in\n  view of dual superconductivity: In the preceeding works, we have given a non-Abelian dual superconductivity\npicture for quark confinement, and demonstrated the numerical evidences on the\nlattice. In this talk, we discuss the confinement and deconfinement phase\ntransition at finite temperature in view of the dual superconductivity. We\ninvestigate chromomagnetic monopole currents induced by chromoelectric flux in\nboth confinement and deconfinement phase by the numerical simulations on a\nlattice at finite temperature, and discuss the role of the chromomagnetic\nmonopole in the confinement/deconfinement phase transition."
    },
    {
        "anchor": "Critical exponents for a spin-charge flip symmetric fixed point in 2+1d\n  with massless Dirac fermions: In the Hamiltonian picture, free spin-$1/2$ Dirac fermions on a bipartite\nlattice have an $O(4)$ (spin-charge) symmetry. Here we construct an interacting\nlattice model with an interaction $V$, which is similar to the Hubbard\ninteraction but preserves the spin-charge flip symmetry. By tuning the coupling\n$V$, we show that we can study the phase transition between the massless\nfermion phase at small-$V$ and a massive fermion phase at large-$V$. We\nconstruct a fermion bag algorithm to study this phase transition and find\nevidence for it to be second order. Numerical study shows that the universality\nclass of the transition is different from the one studied earlier involving the\nHubbard coupling $U$. Here we obtain some critical exponents using lattices up\nto $L=48$.",
        "positive": "Lattice Supersymmetry: Some Ideas from Low Dimensional Models: In the framework of the so called link approach we study exact lattice\nsupersymmetry for the simplest supersymmetric model: N=1 supersymmetry in D=1.\nThe model is described by a lattice with spacing a/2, thus containing twice as\nmany sites as the conventional one. The boson and fermion are related through a\n2pi/a momentum shift, which can provide an interpretation of them being species\ndoublers to each other. An exactly supersymmetric lattice action can be written\nwithin this scheme in momentum representation, which however turns out to be\nnon local in coordinate space."
    },
    {
        "anchor": "Accuracy of Symmetric Partitioned Runge-Kutta Methods for Differential\n  Equations on Lie-Groups: Computer simulations in QCD are based on the discretization of the theory on\na Euclidean lattice. To compute the mean value of an observable, usually the\nHybrid Monte Carlo method is applied. Here equations of motion, derived from an\nHamiltonian, have to be solved numerically. Commonly the Leapfrog\n(Stoermer-Verlet) method or splitting methods with multiple timescales \\`a la\nSexton-Weingarten are used to integrate the dynamical system, defined on a Lie\ngroup. Here we formulate time-reversible higher order integrators based on\nimplicit partitioned Runge-Kutta schemes and show that they allow for larger\nstep-sizes than the Leapfrog method. Since these methods are based on an\ninfinite series of exponential functions, we concentrate on the truncation of\nthis series with respect to the global error and accuracy. Finally, we see that\nthe global error of a SPRK scheme is always even such that a convergence order\nof one is gained for methods with odd convergence order.",
        "positive": "On Majorana fermions on the lattice: The construction of massless Majorana fermions with chiral Yukawa couplings\non the lattice is considered. We find topological obstructions tightly linked\nto those underlying the Nielsen-Ninomiya no-go theorem. In contradistinction to\nchiral fermions the obstructions originate only from the combination of the\nDirac action and the Yukawa term. These findings are used to construct a\nchirally invariant lattice action. We also show that the path intgral of this\ntheory is given by the Pfaffian of the corresponding Dirac operator."
    },
    {
        "anchor": "Renormalization constants of the lattice energy momentum tensor using\n  the gradient flow: We employ a new strategy for a non perturbative determination of the\nrenormalized energy momentum tensor. The strategy is based on the definition of\nsuitable lattice Ward identities probed by observables computed along the\ngradient flow. The new set of identities exhibits many interesting qualities,\narising from the UV finiteness of flowed composite operators. In this paper we\nshow how this method can be used to non perturbatively renormalize the energy\nmomentum tensor for a SU(3) Yang-Mills theory, and report our numerical\nresults.",
        "positive": "Derivation of L\u00fcscher's finite size formula for $N\u03c0$ and $NN$ system: I present derivation of L\\\"uscher's finite size formula for the elastic\n$N\\pi$ and the $NN$ scattering system for several angular momenta from the\nrelativistic quantum field theory."
    },
    {
        "anchor": "Phase transitions in a 3 dimensional lattice loop gas: We investigate, via Monte Carlo simulations, the phase structure of a system\nof closed, nonintersecting but otherwise non-interacting, loops in 3 Euclidean\ndimensions. The loops correspond to closed trajectories of massive particles\nand we find a phase transition as a function of their mass. We identify the\norder parameter as the average length of the loops at equilibrium. This order\nparameter exhibits a sharp increase as the mass is decreased through a critical\nvalue, the behaviour seems to be a cross-over transition. We believe that the\nmodel represents an effective description of the broken-symmetry sector of the\n2+1 dimensional abelian Higgs model, in the extreme strong coupling limit. The\nmassive gauge bosons and the neutral scalars are decoupled, and the relevant\nlow-lying excitations correspond to vortices and anti-vortices. The functional\nintegral can be approximated by a sum over simple, closed vortex loop\nconfigurations. We present a novel fashion to generate non-intersecting closed\nloops, starting from a tetrahedral tessellation of three space. The two phases\nthat we find admit the following interpretation: the usual Higgs phase and a\nnovel phase which is heralded by the appearance of effectively infinitely long\nloops. We compute the expectation value of the Wilson loop operator and that of\nthe Polyakov loop operator. The Wilson loop exhibits perimeter law behaviour in\nboth phases implying that the transition corresponds neither to the restoration\nof symmetry nor to confinement. The effective interaction between external\ncharges is screened in both phases, however there is a dramatic increase in the\npolarization cloud in the novel phase as shown by the energy shift introduced\nby the Wilson loop.",
        "positive": "The profile of the broken string in the confined and deconfined phase in\n  full QCD: We study the profile of the broken string (flux tube) in the maximally\nabelian gauge below and above the finite temperature phase transition in full\nQCD. In the deconfinement phase, the flux tube disappears and the electric\nfield apperas to be Coulomb-like. In the confinement phase, but near $T_c$, at\nshorter distances a flux tube is formed like at zero temperature, while at\nlarger distances the tube disappears similar to the deconfinement phase."
    },
    {
        "anchor": "Quark pseudoscalar vertex and quark mass function with clover fermions :\n  spontaneous symmetry breaking, OPE, symmetry restoration at small volume: We study the quark mass function on hypercubic lattices, in a large range of\nphysical volumes and cutoffs. To avoid the very large Wilson term artefact, we\nexploit the relation between the quark mass function and the pseudoscalar\nvertex in the continuum. We extrapolate to the chiral limit.\n  In function of the physical volume, we observe a striking discontinuity in\nthe properties of chiral extrapolation around a physical volume $L_c 6\n(GeV}^{-1}=1.2 fm$. It is present in the quark mass function, which collapses\nto zero, as well as in the pion mass and the quark condensate as directly\ncalculated from the pseudoscalar correlator. It is strongly reminiscent of the\nphenomenon of chiral symmetry restoration observed by Neuberger and Narayanan\nat $N_C=\\infty$ around the same physical length.\n  In the case of spontaneous symmetry breaking, we confirm that the OPE of the\nquark mass function, involving the quark condensate, is not operative at the\navailable momenta, even taking into account the unusually large high order\ncorrections to the Wilson coefficient calculated by Chetyrkin and Maier ; the\ngap remains large, around a factor 2, even at the largest momenta available to\nus (p \\simeg GeV)",
        "positive": "Chiral properties of two-flavor QCD in small volume and at large lattice\n  spacing: We present results from simulations of two flavors of dynamical overlap\nfermions on 8^4 lattices at three values of the sea quark mass and a lattice\nspacing of about 0.16 fm. We measure the topological susceptibility and the\nchiral condensate. A comparison of the low-lying spectrum of the overlap\noperator with predictions from random matrix theory is made. To demonstrate the\neffect of the dynamical fermions, we compare meson two-point functions with\nquenched results. Algorithmic improvements over a previous publication and the\nperformance of the algorithm are discussed."
    },
    {
        "anchor": "On the B*' --> B transition: We present a first Nf=2 lattice estimate of the hadronic coupling g_12 which\nparametrises the strong decay of a radially excited B* meson into the ground\nstate B meson at zero recoil. We work in the static limit of Heavy Quark\nEffective Theory (HQET) and solve a Generalised Eigenvalue Problem (GEVP),\nwhich is necessary for the extraction of excited state properties. After an\nextrapolation to the continuum limit and a check of the pion mass dependence,\nwe obtain g_12 = -0.17(4).",
        "positive": "Multiple-particle interaction in $1+1$ dimensional lattice model: Finite volume multiple-particle interaction is studied in a two-dimensional\ncomplex $\\phi^4$ lattice model. The existence of analytical solutions to the\n$\\phi^4$ model in two-dimensional space and time makes it a perfect model for\nthe numerical study of finite volume effects of multi-particle interaction. The\nspectra from multiple particles are extracted from the Monte Carlo simulation\non various lattices in several moving frames. The $S$-matrix of multi-particle\nscattering in $\\phi^4$ theory is completely determined by two fundamental\nparameters: single particle mass and the coupling strength of two-to-two\nparticle interaction. These two parameters are fixed by studying\nsingle-particle and two-particle spectra. Due to the absence of the diffraction\neffect in the $\\phi^{4}$ model, three-particle quantization conditions are\ngiven in a simple analytical form. The three-particle spectra from simulation\nshow remarkable agreement with the prediction of exact solutions."
    },
    {
        "anchor": "Hybrid and Orbitally Excited Mesons in Full QCD: We present results for the hybrid meson spectrum produced by gluonic\nexcitations in full QCD using Wilson fermions. For the spin-exotic mesons with\nJ^{PC}=1^{-+}, 0^{+-}, and 2^{+-} we find the lightest state to be 1^{-+} with\na mass of 1.9(2) GeV. Results obtained for orbitally excited mesons are also\npresented.",
        "positive": "The Rational Hybrid Monte Carlo Algorithm: The past few years have seen considerable progress in algorithmic development\nfor the generation of gauge fields including the effects of dynamical fermions.\nThe Rational Hybrid Monte Carlo (RHMC) algorithm, where Hybrid Monte Carlo is\nperformed using a rational approximation in place the usual inverse quark\nmatrix kernel is one of these developments. This algorithm has been found to be\nextremely beneficial in many areas of lattice QCD (chiral fermions, finite\ntemperature, Wilson fermions etc.). We review the algorithm and some of these\nbenefits, and we compare against other recent algorithm developements. We\nconclude with an update of the Berlin wall plot comparing costs of all popular\nfermion formulations."
    },
    {
        "anchor": "Bayesian interpretation of Backus-Gilbert methods: The extraction of spectral densities from Euclidean correlators evaluated on\nthe lattice is an important problem, as these quantities encode physical\ninformation on scattering amplitudes, finite-volume spectra, inclusive decay\nrates, and transport coefficients. In this contribution, we show that the\nBayesian approach to this \"inverse\" problem, based on Gaussian processes, can\nbe reformulated in a way that yields a solution equivalent, up to statistical\nuncertainties, to the one obtained in a Backus-Gilbert approach. After\ndiscussing this equivalence, we point out its implications for a reliable\ndetermination of spectral densities from lattice simulations.",
        "positive": "Chiral Analysis of the Generalized Form Factors of the Nucleon: We apply the methods of Chiral Perturbation Theory to the analysis of the\nfirst moments of the Generalized Parton Distributions in a Nucleon, usually\nknown as generalized form factors. These quantities are currently also under\ninvestigation in Lattice QCD analyses of baryon structure, providing simulation\nresults at large quark masses to be extrapolated to the \"real world\" via Chiral\nEffective Field Theory. We have performed a leading-one-loop calculation in the\ncovariant framework of Baryon Chiral Perturbation Theory (BChPT), predicting\nboth the momentum and the quark-mass dependence for all the vector and axial\n(generalized) form factors. In particular we discuss the results for the limit\nof vanishing four-momentum transfer where the GPD-moments reduce to the well\nknown moments of Parton Distribution Functions (PDFs). We fit our results to\navailable lattice QCD data, extrapolating down to the physical point. We\nconclude by presenting outstanding results from a combined fit to different\nGPDs-moments."
    },
    {
        "anchor": "On light vector mesons and chiral SU(3) extrapolations: A chiral extrapolation of the light vector meson masses in the up, down and\nstrange quark masses of QCD is presented. We apply an effective chiral\nLagrangian based on the hadrogenesis conjecture to QCD lattice ensembles of\nPACS-CS, QCDSF-UKQCD and HSC in the strict isospin limit. The leading orders\nlow-energy constants are determined upon a global fit to the lattice data set.\nWe use the pion and kaon masses as well as the size of the finite volume as\nlattice ensemble parameters only. The quark mass ratio on the various ensembles\nare then predicted in terms of our set of low-energy constants. An accurate\nreproduction of the vector meson masses and quark-mass ratios as provided by\nthe lattice collaborations and the Particle Data Group (PDG) is achieved.\nParticular attention is paid to the \\omega-\\phi mixing phenomenon, which is\ndemonstrated to show a strong quark mass dependence.",
        "positive": "Large N limit of the IKKT matrix model: Using the dynamical triangulation approach we perform a numerical study of a\nsupersymmetric random surface model that corresponds to the large N limit of\nthe four-dimensional version of the IKKT matrix model. We show that the\naddition of fermionic degrees of freedom suppresses the spiky world-sheet\nconfigurations that are responsible for the pathological behaviour of the\npurely bosonic model. We observe that the distribution of the gyration radius\nhas a power-like tail p(R) ~ R^{-2.4}. We check numerically that when the\nnumber of fermionic degrees of freedom is not susy-balanced, p(R) grows with\n$R$ and the model is not well-defined. Numerical sampling of the configurations\nin the tail of the distribution shows that the bosonic degrees of freedom\ncollapse to a one-dimensional tube with small transverse fluctuations. Assuming\nthat the vertex positions can fluctuate independently within the tube, we give\na theoretical argument which essentially explains the behaviour of p(R) in the\ndifferent cases, in particular predicting p(R) ~ R^{-3} in the supersymmetric\ncase. Extending the argument to six and ten dimensions, we predict p(R) ~\nR^{-7} and p(R) ~ R^{-15}, respectively."
    },
    {
        "anchor": "The hadronic vacuum polarization and automatic O(a) improvement for\n  twisted mass fermions: The vacuum polarization tensor and the corresponding vacuum polarization\nfunction are the basis for calculations of numerous observables in lattice QCD.\nExamples are the hadronic contributions to lepton anomalous magnetic moments,\nthe running of the electroweak and strong couplings and quark masses.\nQuantities which are derived from the vacuum polarization tensor often involve\na summation of current correlators over all distances in position space leading\nthus to the appearance of short-distance terms. The mechanism of O(a)\nimprovement in the presence of such short-distance terms is not directly\ncovered by the usual arguments of on-shell improvement of the action and the\noperators for a given quantity. If such short-distance contributions appear,\nthe property of O(a) improvement needs to be reconsidered. We discuss the\neffects of these short-distance terms on the vacuum polarization function for\ntwisted mass lattice QCD and find that even in the presence of such terms\nautomatic O(a) improvement is retained if the theory is tuned to maximal twist.",
        "positive": "Vacuum structure and Casimir scaling in Yang-Mills theories: The vacuum of Yang-Mills theories can be imagined as a magnetically\ndisordered medium with domain structure, with color magnetic flux in each\ndomain quantized in units corresponding to the gauge group center. This model\nleads to the prediction of Casimir scaling, i.e. the proportionality of string\ntensions of potentials (at intermediate distances) between color sources from\nhigher-representations to eigenvalues of the quadratic Casimir operator. I\npresent evidence for Casimir scaling in G(2) lattice gauge theory. I also\ndiscuss support for some ingredients of the model from the recently conjectured\nform of the Yang-Mills ground-state wave-functional."
    },
    {
        "anchor": "Lattice QCD and baryon-baryon interactions: HAL QCD method: In this article, we review the HAL QCD method to investigate baryon-baryon\ninteractions such as nuclear forces in lattice QCD. We first explain our\nstrategy in detail to investigate baryon-baryon interactions by defining\npotentials in field theories such as QCD. We introduce the Nambu-Bethe-Salpeter\n(NBS) wave functions in QCD for two baryons below the inelastic threshold. We\nthen define the potential from NBS wave functions in terms of the derivative\nexpansion, which is shown to reproduce the scattering phase shifts correctly\nbelow the inelastic threshold. Using this definition, we formulate a method to\nextract the potential in lattice QCD. Secondly, we discuss pros and cons of the\nHAL QCD method, by comparing it with the conventional method, where one\ndirectly extracts the scattering phase shifts from the finite volume energies\nthrough the L\\\"uscher's formula. We give several theoretical and numerical\nevidences that the conventional method combined with the naive plateau fitting\nfor the finite volume energies in the literature so far fails to work on\nbaryon-baryon interactions due to contaminations of elastic excited states. On\nthe other hand, we show that such a serious problem can be avoided in the HAL\nQCD method by defining the potential in an energy-independent way. We also\ndiscuss systematics of the HAL QCD method, in particular errors associated with\na truncation of the derivative expansion. Thirdly, we present several results\nobtained from the HAL QCD method, which include (central) nuclear force, tensor\nforce, spin-orbital force, and three nucleon force. We finally show the latest\nresults calculated at the nearly physical pion mass, $m_\\pi \\simeq 146$ MeV,\nincluding hyperon forces which lead to form $\\Omega\\Omega$ and $N\\Omega$\ndibaryons.",
        "positive": "Exploiting the hopping parameter expansion in the hybrid Monte Carlo\n  (HMC) simulation of lattice QCD with two degenerate flavours of Wilson\n  fermions: We show how the hopping parameter expansion at order $\\kappa^2$ and\n$\\kappa^4$ can be exploited in the simulation of lattice QCD with two flavours\nof degenerate Wilson fermions. A natural extension of this idea is a\n\"UV-filtering\" by using rooted polynomials. These approaches can be easily\ncombined with, for example, mass preconditioning. First numerical tests are\nperformed for the Wilson gauge action at $\\beta=5.6$ and $\\kappa=0.156$ and\n$0.1575$."
    },
    {
        "anchor": "Results from Lattice QCD for baryons containing a heavy quark: We present the calculation of the spectrum of baryons containing one heavy\nquark. Heavy baryon and meson mass splittings are computed and compared with\nexperiment. We give preliminary results for the form factor $G_1$ for the\nsemileptonic decay $ \\Lambda_b \\rightarrow \\Lambda_c l \\bar{\\nu} $ and\ninvestigate its flavour symmetry.",
        "positive": "Optimizing Chirality and Scaling of Lattice Fermions: If we construct a lattice fermion formulation, there are a number of goals to\nbe considered: doubling should be avoided; even at finite lattice spacing, we\nwant to represent chiral symmetry in a sound way; and we are seeking a good\nscaling behavior. Conceptually we have to require locality, and for practical\npurposes we even desire a high level of locality. A further issue is a good\napproximation to rotation invariance. Last but not least the formulation should\nbe simple enough to allow for efficient simulations. Here we report on a\nconstruction, which is designed to do justice to all of these goals."
    },
    {
        "anchor": "Particle Projection Using a Complex Langevin Method: Using complex stochastic quantization, we implement a particle-number\nprojection technique on the partition function of spin-1/2 fermions at finite\ntemperature on the lattice. We discuss the method, its application towards\nobtaining the thermal properties of finite Fermi systems in three spatial\ndimensions, and results for the first five virial coefficients of\none-dimensional, attractively interacting fermions.",
        "positive": "Lattice Study of Spectator Effects in $b$-hadron Decays: The Heavy Quark Expansion (HQE) gives an expansion of inclusive decay rates\nof $b$-hadrons as a simultaneous series in $\\alpha_s$ and $1/m_b$, in terms of\nperturbatively defined coefficients and non-perturbative matrix elements.\nSpectator effects arise from the dimension-$6$ operators in the HQE in which\nalong with the heavy quark, a light spectator quark from the hadron\nparticipates in the weak decay. In this work, we provide a lattice\ndetermination of the bare matrix elements that contribute to the spectator\neffects for the $B^+$-meson, $B_d$-meson and the $\\Lambda_b$-baryon. The\ncomputations were performed on two separate lattice spacings of the RBC-UKQCD\n(2+1)-flavor Domain Wall Fermion ensembles. Renormalization and continuum\nextrapolation of the matrix elements have not yet been computed, and are left\nto future work."
    },
    {
        "anchor": "Strong coupling analysis of Aoki phase in Staggered-Wilson fermions: We study strong-coupling lattice QCD with staggered-Wilson fermions, with an\nemphasis on the possibility of spontaneous parity breaking. We perform\neffective potential analysis in the strong-coupling limit. From gap equations\nwe find the pion condensate becomes nonzero in some range of a mass parameter,\nwhich indicates the existence of the parity-broken phase. We also find massless\npions and PCAC relations around the second-order phase boundary. These results\nsuggest that we can take the chiral limit by tuning a mass parameter in lattice\nQCD with staggered-Wilson fermions as with the Wilson fermion.",
        "positive": "Lattice Gauge Fixing, Gribov Copies and BRST Symmetry: We show that a modification of the BRST lattice quantization allows to\ncircumvent an old paradox, formulated by Neuberger, related to lattice Gribov\ncopies and non-perturbative BRST invariance. In the continuum limit the usual\nBRST formulation is recovered."
    },
    {
        "anchor": "Renormalized Polyakov loop in the Fixed Scale Approach: I compute Polyakov loop, the deconfinement order parameter, for SU(2) lattice\ngauge theory using the fixed scale approach for several different scales and\nshow how to obtain a renormalized physical order parameter. The generalization\nto other gauge theories, including quenched or full QCD, is straightforward.",
        "positive": "Three Photon Decay of $J/\u03c8$ from Lattice QCD: Three photon decay rate of $J/\\psi$ is studied using two $N_f=2$ twisted mass\ngauge ensembles with lattice spacings $a\\simeq 0.085$ fm (I) and $0.067$\nfm(II). Using a new method, only the correlation functions directly related to\nthe physical decay width are computed with all polarizations of the initial and\nfinal states summed over. Our results for such rare decay on the two ensembles\nare: $\\mathcal{B}_{I,II}(J/\\psi\\rightarrow 3\\gamma)=(1.614 \\pm 0.016 \\pm\n0.261)\\times 10^{-5},(1.809 \\pm 0.051 \\pm 0.295)\\times 10^{-5}$ where the first\nerrors are statistical and the second are estimates from systematics. We also\npropose a method to analyze the Dalitz plot of the corresponding process based\non the lattice data which can provide direct information for the experiments."
    },
    {
        "anchor": "Leading-order hadronic contribution to the anomalous magnetic moment of\n  the muon from N_f=2+1+1 twisted mass fermions: We present results for the leading order QCD correction to the anomalous\nmagnetic moment of the muon including the first two generations of quarks as\ndynamical degrees of freedom. Several light quark masses are examined in order\nto yield a controlled extrapolation to the physical pion mass. We analyse\nensembles for three different lattice spacings and several volumes in order to\ninvestigate lattice artefacts and finite-size effects, respectively. We also\nprovide preliminary results for this quantity for two flavours of\nmass-degenerate quarks at the physical value of the pion mass.",
        "positive": "Numerical simulation of the $\\mathcal{N}=(2,2)$ Landau-Ginzburg model: The two-dimensional $\\mathcal{N}=(2,2)$ Wess-Zumino (WZ) model with a cubic\nsuperpotential is numerically studied with a momentum-cutoff regularization\nthat preserves supersymmetry. A numerical algorithm based on the Nicolai map is\nemployed and the resulting configurations have no autocorrelation. This system\nis believed to flow to an $\\mathcal{N}=(2,2)$ superconformal field theory\n(SCFT) in the infrared (IR), the $A_2$ model. From a finite-size scaling\nanalysis of the susceptibility of the scalar field in the WZ model, we\ndetermine $1-h-\\Bar{h}=0.616(25)(13)$ for the conformal dimensions $h$ and\n$\\Bar{h}$, while $1-h-\\Bar{h}=0.666...$ for the $A_2$ model. We also measure\nthe central charge in the IR region from a correlation function between\nconserved supercurrents and obtain $c=1.09(14)(31)$ ($c=1$ for the $A_2$\nmodel). These results are consistent with the conjectured emergence of the\n$A_2$ model, and at the same time demonstrate that numerical studies can be\ncomplementary to analytical investigations for this two-dimensional\nsupersymmetric field theory."
    },
    {
        "anchor": "Lattice study on $\u03b7_{c2}$ and X(3872): Properties of $2^{-+}$ charmonium $\\eta_{c2}$ are investigated in quenched\nlattice QCD. The mass of $\\eta_{c2}$ is determined to be 3.80(3) GeV, which is\nclose to the mass of $D$-wave charmonium $\\psi(3770)$ and in agreement with\nquark model predictions. The transition width of $\\eta_{c2}\\to \\gamma J/\\psi$\nis also obtained with a value $\\Gamma=3.8(9)$ keV. Since the possible $2^{-+}$\nassignment to X(3872) has not been ruled out by experiments, our results help\nto clarify the nature of X(3872).",
        "positive": "Lattice simulations of technicolour theories with adjoint fermions and\n  supersymmetric Yang-Mills theory: Theories with fermions in the adjoint representation have several interesting\napplications in extensions of the standard model. The conformal window for\nthese theories is of particular interest for technicolour extensions. We\npresent here our newest results for the spectrum of $N_f=2$ adjoint QCD and\ncompare them with the predictions for a conformal behaviour. The comparison\nwith supersymmetric Yang-Mills theory, investigated with the same methods, will\nhelp to distinguish more clearly the conformal and the confining scenario. The\nspectrum includes additional fermionic states that are not present in QCD. We\nprovide results for the mass of these states and discuss their phenomenological\nrelevance. In addition we have done preliminary investigations of the singlet\nscalar meson state."
    },
    {
        "anchor": "QCD thermodynamics with colour-sextet quarks: We study QCD with two flavours of colour-sextet quarks as a candidate\nwalking-Technicolor theory. We simulate lattice QCD with two flavours of\ncolour-sextet staggered quarks at finite temperatures to observe the scales of\nconfinement and chiral-symmetry breaking. These should give us some indication\nas to whether the massless theory has an infrared fixed point making it a\nconformal field theory, or whether it exhibits confinement and chiral symmetry\nbreaking with a slowly varying coupling constant, i.e. `walks'. We find that\nunlike the case with fundamental quarks, the deconfinement and chiral-symmetry\nrestoration transitions are far apart. The values of $\\beta=6/g^2$ for both\ntransitions increase when $Ta$ is decreased from 1/4 to 1/6 as would be\nexpected for finite temperature transitions of an asymptotically-free field\ntheory. So far we see no suggestion of conformal behaviour.",
        "positive": "Quenched $SU(3)$ hadron spectroscopy using improved fermionic and gauge\n  actions: We present results of quenched $SU(3)$ hadron spectroscopy using $\\order(a)$\nimproved Wilson fermions. The configurations were generated using an\n$\\order(a^2)$ improved 6-link $SU(3)$ pure gauge action at $\\beta$'s\ncorresponding to lattice spacings of $0.43$, $0.25$, $0.20$, $0.18$, and $0.15$\nfm. We find evidence that fermionic scaling violations are consistent with\n$\\order(a^2)$ errors."
    },
    {
        "anchor": "Improved B -> pi l nu_l form factors from the lattice: We present the results of a lattice computation of the form factors for B^0\n->pi^- l^+nu_l decays near zero-recoil. These results will allow a\ndetermination of the CKM matrix element |Vub| when measurements of the\ndifferential decay rate become available. We also provide models for\nextrapolation of the form factors and rate to the full recoil range. Our\ncomputation is performed in the quenched approximation to QCD on a 24^3x48\nlattice at beta=6.2, using a non-perturbatively O(a)-improved action. The\nmasses of all light valence quarks involved are extrapolated to their physical\nvalues.",
        "positive": "Full QCD light hadron spectrum from the CP-PACS: We report on an on-going two-flavor full QCD study on CP-PACS using an\nRG-improved gauge action and a tadpole-improved SW quark action. Runs are made\nfor three lattice spacings $a^{-1}\\approx 0.9$, 1.3, and 2.5 GeV on\n$12^3\\times24$, $16^3\\times32$, and $24^3\\times48$ lattices. Four sea quark\nmasses having $m_{\\rm PS}/m_{\\rm V} \\approx 0.8$--0.6 are simulated, for each\nof which hadron masses are evaluated for valence quark masses corresponding to\n$m_{\\rm PS}/m_{\\rm V} \\approx 0.8$--0.5. Results for hadron and light quark\nmasses are presented and compared with those obtained in quenched QCD."
    },
    {
        "anchor": "Lattice Calculations of Semileptonic Form Factors: We review the results of lattice QCD calculations of form factors for\nsemileptonic decays of D and B mesons. We also mention results for semileptonic\ndecays of b baryons and the rare radiative decay B to K* gamma.",
        "positive": "QCD at Zero Baryon Density and the Polyakov Loop Paradox: We compare the grand canonical partition function at fixed chemical potential\nmu with the canonical partition function at fixed baryon number B, formally and\nby numerical simulations at mu=0 and B=0 with four flavours of staggered\nquarks. We verify that the free energy densities are equal in the thermodynamic\nlimit, and show that they can be well described by the hadron resonance gas at\nT < T_c and by the free fermion gas at T>T_c.\n  Small differences between the two ensembles, for thermodynamic observables\ncharacterising the deconfinement phase transition, vanish with increasing\nlattice size. These differences are solely caused by contributions of non-zero\nbaryon density sectors, which are exponentially suppressed with increasing\nvolume. The Polyakov loop shows a different behaviour: for all temperatures and\nvolumes, its expectation value is exactly zero in the canonical formulation,\nwhereas it is always non-zero in the commonly used grand-canonical formulation.\nWe clarify this paradoxical difference, and show that the non-vanishing\nPolyakov loop expectation value is due to contributions of non-zero triality\nstates, which are not physical, because they give zero contribution to the\npartition function."
    },
    {
        "anchor": "On the calculation and use of non-zero momentum correlators in lattice\n  simulations: In lattice simulations one generally projects correlators over zero spatial\nmomentum to calculate masses and related spectral data. The sum over space\nlattice points, however, discards information which may be useful especially in\nthe calculation of disconnected diagrams. By using momentum conservation, the\ncalculation of non-zero momentum components of disconnected diagrams and other\nquantities related to space convolutions can be done with little additional\ncomputational cost and may be useful in the analysis of disconnected\ncorrelators.",
        "positive": "Renormalization of the static-light axial current: We discuss the determination of the heavy-light axial current renormalization\nin the static approximation, using a new method based on the Schr\\\"odinger\nFunctional (SF). Previous perturbative results for the renormalization constant\nare confirmed."
    },
    {
        "anchor": "Reply to A. Patrascioiu's and E. Seiler's comment on our paper \"The\n  two-phase issue in the O(n) non-linear sigma-model: a Monte Carlo study\": We reply to a comment by A. Patrascioiu and E. Seiler appeared in\nhep-lat/9608138 on our paper hep-lat/9608002.",
        "positive": "Finite Size Analysis of the U(1) Phase Transition using the World-sheet\n  Formulation: We present a high statistics analysis of the pure gauge compact U(1) lattice\ntheory using the the world-sheet or Lagrangian loop representation. We have\napplied a simulation method that deals directly with (gauge invariant) integer\nvariables on plaquettes. As a result we get a significant amelioration of the\nsimulation that allows to work with large lattices avoiding the metaestability\nproblems that appear using the standard Wilson formulation."
    },
    {
        "anchor": "Form factors for rare B decays: strategy, methodology, and numerical\n  study: We investigate the combined use of moving NRQCD and stochastic sources in\nlattice calculations of form factors describing rare B and B_s decays. Moving\nNRQCD leads to a reduction of discretisation errors compared to standard NRQCD.\nStochastic sources are tested for reduction of statistical errors.",
        "positive": "Moments of pseudoscalar meson distribution amplitudes from the lattice: Based on lattice simulations with two flavours of dynamical, O(a)-improved\nWilson fermions we present results for the first two moments of the\ndistribution amplitudes of pseudoscalar mesons at several values of the valence\nquark masses. By extrapolating our results to the physical masses of up/down\nand strange quarks, we find the first two moments of the K^+ distribution\namplitude and the second moment of the pi^+ distribution amplitude. We use\nnonperturbatively determined renormalisation coefficients to obtain results in\nthe MSbar scheme. At a scale of 4 GeV^2 we find a_2^pi=0.201(114) for the\nsecond Gegenbauer moment of the pion's distribution amplitude, while for the\nkaon, a_1^K=0.0453(9)(29) and a_2^K=0.175(18)(47)."
    },
    {
        "anchor": "Pion condensation at lower than physical quark masses: In QCD at large enough isospin chemical potential Bose-Einstein Condensation\n(BEC) takes place, separated from the normal phase by a phase transition. From\nprevious studies the location of the BEC line at the physical point is known.\nIn the chiral limit the condensation happens already at infinitesimally small\nisospin chemical potential for zero temperature according to chiral\nperturbation theory. The thermal chiral transition at zero density might then\nbe affected, depending on the shape of the BEC boundary, by its proximity. As a\nfirst step towards the chiral limit, we perform simulations of 2+1 flavors QCD\nat half the physical quark masses. The position of the BEC transition is then\nextracted and compared with the results at physical masses.",
        "positive": "Low Energy Spectrum of SU(2) Lattice Gauge Theory: An Alternate Proposal\n  via Loop Formulation: We show that, prepotential formulation of gauge theories on honeycomb lattice\nyields local loop states, which are free from any spurious loop degrees of\nfreedom and hence exact and orthonormal. We also illustrate that, the dynamics\nof orthonormal loop states are exactly same in both the square and honeycomb\nlattices. We further extend this construction to arbitrary dimensions.\nUtilizing this result, we make a mean field ansatz for loop configurations for\nSU(2) lattice gauge theory in $2+1$ dimension contributing to the low energy\nsector of the spectrum. Using variational analysis, we show that, this type of\nmean loop configurations has two distinct phases in the strong and weak\ncoupling regime and shows a first order transition at $g=1$. We then propose a\nreduced Hamiltonian to describe the dynamics of the theory within the mean\nfield ansatz. We further work with the mean loop configuration obtained at the\nweak coupling regime and analytically calculate the spectrum of the reduced\nHamiltonian. The spectrum matches with that of the existing literature in this\nregime, establishing our ansatz to be a valid alternate one which is far more\neasier to handle for computation."
    },
    {
        "anchor": "4d Simplicial Quantum Gravity: Matter Fields and the Corresponding\n  Effective Action: Four-dimensional simplicial quantum gravity is modified either by coupling it\nto U(1) gauge fields or by introducing a measure weighted by the orders of the\ntriangles. Strong coupling expansion and Monte Carlo simulations are used.\nAlthough the two modifications of the standard pure-gravity model are\napparently very distinct, they produce strikingly similar results, as far as\nthe geometry of random manifolds is concerned. In particular, for an\nappropriate choice of couplings, the branched polymer phase is replaced by a\ncrinkled phase, characterized by the susceptibility exponent $\\gamma < 0$ and\nthe fractal dimension $d_H > 2$. The quasi-equivalence between the two models\nis exploited to get further insight into the extended phase diagram of the\ntheory.",
        "positive": "A multigrid accelerated eigensolver for the Hermitian Wilson-Dirac\n  operator in lattice QCD: Eigenvalues of the Hermitian Wilson-Dirac operator are of special interest in\nseveral lattice QCD simulations, e.g., for noise reduction when evaluating\nall-to-all propagators. In this paper we present a Davidson-type eigensolver\nthat utilizes the structural properties of the Hermitian Wilson-Dirac operator\n$Q$ to compute eigenpairs of this operator corresponding to small eigenvalues.\nThe main idea is to exploit a synergy between the (outer) eigensolver and its\n(inner) iterative scheme which solves shifted linear systems. This is achieved\nby adapting the multigrid DD-$\\alpha$AMG algorithm to a solver for shifted\nsystems involving the Hermitian Wilson-Dirac operator. We demonstrate that\nupdating the coarse grid operator using eigenvector information obtained in the\ncourse of the generalized Davidson method is crucial to achieve good\nperformance when calculating many eigenpairs, as our study of the local\ncoherence shows. We compare our method with the commonly used software-packages\nPARPACK and PRIMME in numerical tests, where we are able to achieve significant\nimprovements, with speed-ups of up to one order of magnitude and a near-linear\nscaling with respect to the number of eigenvalues. For illustration we compare\nthe distribution of the small eigenvalues of $Q$ on a $64\\times 32^3$ lattice\nwith what is predicted by the Banks-Casher relation in the infinite volume\nlimit."
    },
    {
        "anchor": "Truncation Effects in Monte Carlo Renormalization Group Improved Lattice\n  Actions: We study truncation effects in the SU(3) gauge actions obtained by the Monte\nCarlo renormalization group method. By measuring the heavy quark potential we\nfind that the truncation effects in the actions coarsen the lattice by 40-50 %\nfrom the original blocked lattice. On the other hand, we find that rotational\nsymmetry of the heavy quark potentials is well recovered on such coarse\nlattices, which may indicate that rotational symmetry breaking terms are easily\ncancelled out by adding a short distance operator. We also discuss the\npossibility of reducing truncation effects.",
        "positive": "QCD phase diagram for small densities from simulations at imaginary mu: We present results on the QCD phase diagram for small densities without\nreweighting. Our simulations are performed with an imaginary chemical potential\nmu_I for which the fermion determinant is positive. On an 8^3x4 lattice with 2\nflavors of staggered quarks, we map out the pseudo-critical temperature\nT_c(mu_I). For mu_I/T < pi/3, this is an analytic function whose Taylor\nexpansion converges rapidly, with truncation errors smaller than statistical\nones. The result is analytically continued to give the location of the\npseudo-critical line for real mu_B<500 MeV."
    },
    {
        "anchor": "Chiral Lagrangian and spectral sum rules for two-color QCD at high\n  density: We report on our analytical study of two-color QCD with an even number of\nflavors at high baryon density. Based on the pattern of chiral symmetry\nbreaking induced by BCS-type diquark pairing we construct the low-energy\neffective Lagrangian for the Nambu-Goldstone bosons. We also identify a new\nepsilon-regime at high baryon density and derive Leutwyler-Smilga-type spectral\nsum rules for the complex eigenvalues of the Dirac operator in terms of the\nfermion gap. Our results can in principle be tested in lattice QCD simulations.",
        "positive": "The fate of $U_A(1)$ and topological features of QCD at finite\n  temperature: The nature of chiral phase transition for QCD with two light quark flavors is\nnot yet completely resolved. This is primarily because one has to understand\nwhether or not the anomalous U(1) symmetry in the flavor sector is effectively\nrestored along with the chiral symmetry. Since the physics near the chiral\nphase transition is essentially non-perturbative, we employ first principles\nlattice techniques to address this issue. We use overlap fermions, which have\nexact chiral symmetry on the lattice, to probe the anomalous U(1) symmetry\nviolation of 2+1 flavor dynamical QCD configurations with domain wall fermions.\nThe latter also optimally preserves chiral and flavor symmetries on the\nlattice. We observe that the anomalous U(1) is not effectively restored in the\nchiral crossover region. We perform a systematic study of the finite size and\ncut-off effects since the signals of U(1) violation are sensitive to it. For\nthe same reasons we also compare our results from the continuum extrapolated\nresults of the QCD Dirac spectrum obtained from a different lattice\ndiscretization called Highly Improved Staggered Quarks. Our studies also\nprovide a glimpse of the microscopic topological structures of the QCD medium\nthat are responsible for the strongly interacting nature of the quark gluon\nplasma phase and related to the physics of confinement and chiral symmetry\nbreaking."
    },
    {
        "anchor": "Monopoles, confinement and deconfinement of (2+1)D compact lattice QED\n  in external fields: The compact Abelian model in three space--time dimensions is studied in the\npresence of external electromagnetic fields at finite temperatures. We show\nthat the deconfinement phase transition is independent on the strength of the\nexternal fields. This result is in agreement with our observation that the\nexternal fields create small--size magnetic dipoles from the vacuum which do\nnot influence the confining properties of the model. Contrary to the\ndeconfinement phase, the internal field in the direction of the applied\nexternal field is attenuated in the confinement phase, this screening becomes\nstronger with decreasing temperature.",
        "positive": "Chiral symmetry breaking and monopole dynamics in non-compact QED3\n  coupled to a four-fermi interaction: We present results from the first lattice simulations of three dimensional\nnon-compact quantum electrodynamics (QED3) with N_f four-component fermion\nflavors coupled to a weak Z(2) chirally invariant four-fermi interaction.\nResults with $N_f \\ge 4$ show that the scaling near the strong coupling chiral\ntransition or sharp crossover is determined by the 3d Gross Neveu\nultraviolet-stable renormalization group fixed point. Small deviations of the\nN_f=4 critical exponents from the respective Gross Neveu ones, hint at evidence\nfor non-zero fermion mass generated by the gauge fields dynamics that might\nhave been enhanced by the four-fermi coupling. It is also shown that the\nscaling region is suppressed at weak four-fermi couplings and large N_f values.\nMeasurements of i) a monopole susceptibility which is the polarizability of the\nmonopole configurations, and ii) the density of isolated monopoles, imply that\nfor $N_f \\ge 1$ and weak gauge couplings the monopoles do not affect the\ntheory's confining properties, because they are shielded."
    },
    {
        "anchor": "The static quark potential from a multilevel algorithm for the improved\n  gauge action: We generalize the multilevel algorithm of Luescher and Weisz to study SU(N)\nYang-Mills theories with the tree-level improved gauge action. We test this\nalgorithm, comparing its results with those obtained using the Wilson action,\nin SU(3) and SU(4) Yang-Mills theories in 2+1 and 3+1 dimensions. We measure\nthe static quark potential and extract the Luescher term, predicted by the\nbosonic string theory.",
        "positive": "Thermodynamics at Strong Coupling on Anisotropic Lattices: Lattice QCD with staggered fermions at strong coupling has long been studied\nin a dual representation to circumvent the finite baryon density sign problem.\nMonte Carlo simulations at finite temperature and density require anisotropic\nlattices. Recent results that established the non-perturbative functional\ndependence between the bare anisotropy $\\gamma$ and the physical anisotropy\n$a_s/a_t$ in the chiral limit are now extended to finite quark mass. We\nillustrate how the calibration of the anisotropy works and discuss the\nconsequences of the anisotropy on thermodynamic observables. We also show first\nresults on the energy density and pressure in the QCD phase diagram in the\nstrong coupling regime."
    },
    {
        "anchor": "Evading the sign problem in random matrix simulations: We show how the sign problem occurring in dynamical simulations of random\nmatrices at nonzero chemical potential can be avoided by judiciously combining\nmatrices into subsets. For each subset the sum of fermionic determinants is\nreal and positive such that importance sampling can be used in Monte Carlo\nsimulations. The number of matrices per subset is proportional to the matrix\ndimension. We measure the chiral condensate and observe that the statistical\nerror is independent of the chemical potential and grows linearly with the\nmatrix dimension, which contrasts strongly with its exponential growth in\nreweighting methods.",
        "positive": "Determination of the Gradient Flow Scale $t_0$ from a Mixed Action with\n  Wilson Twisted Mass Valence Quarks: We perform the scale setting procedure of a mixed action setup consisting of\nvalence Wilson twisted mass fermions at maximal twist on CLS ensembles with\n$N_f=2+1$ flavours of $O(a)$-improved Wilson sea quarks. We determine the\ngradient flow scale $t_0$ using pion and kaon masses and decay constants in the\nisospin symmetric limit of QCD as external physical input. We employ model\nvariation techniques to explore the systematic uncertainties in the extraction\nof the ground state signal of lattice observables, as well as for the\ncontinuum-chiral extrapolations. We observe that the combined analysis of the\nmixed action data with that based on $O(a)$-improved Wilson valence quarks,\nprovides an improved control of the extrapolation of $t_0$ to the physical\npoint."
    },
    {
        "anchor": "Numerical corrections to the strong coupling effective Polyakov-line\n  action for finite T Yang-Mills theory: We consider a three-dimensional effective theory of Polyakov lines derived\npreviously from lattice Yang-Mills theory and QCD by means of a resummed strong\ncoupling expansion. The effective theory is useful for investigations of the\nphase structure, with a sign problem mild enough to allow simulations also at\nfinite density. In this work we present a numerical method to determine\nimproved values for the effective couplings directly from correlators of the 4d\nYang-Mills theory. For values of the gauge coupling up to the vicinity of the\nphase transition, the dominant short range effective coupling are well\ndescribed by their corresponding strong coupling series. We provide numerical\nresults also for the longer range interactions, Polyakov lines in higher\nrepresentations as well as four-point interactions, and discuss the growing\nsignificance of non-local contributions as the lattice gets finer. Within this\napproach the critical Yang-Mills coupling $\\beta_c$ is reproduced to better\nthan one percent from a one-coupling effective theory on $N_\\tau=4$ lattices\nwhile up to five couplings are needed on $N_\\tau=8$ for the same accuracy.",
        "positive": "Tuning for Three-flavors of Anisotropic Clover Fermions with Stout-link\n  Smearing: In this work we perform the parameter tuning of three flavors of dynamical\nclover quarks on anisotropic lattices. The fermion action uses\nthree-dimensional spatial stout-link smearing. The gauge anisotropy is\ndetermined in a small box with Schr\\\"odinger background using Wilson-loop\nratios. The fermion anisotropy is obtained from studying the meson dispersion\nrelation with antiperiodic boundary conditions in the time direction. The\nspatial and temporal clover coefficients are fixed to the tree-level\ntadpole-improved values, and we demonstrate that they satisfy the\nnonperturbative conditions as determined by the Schr\\\"odinger functional\nmethod. For the desired lattice spacing $a_s\\approx 0.12$ fm and renormalized\nanisotropy $\\xi=3.5$, we find the gauge and fermionic anisotropies can be fixed\nto quark mass independent values up through the strange quark mass. This work\nlays the foundation needed for further studies of the excited-state hadron\nspectrum."
    },
    {
        "anchor": "Nucleon axial and pseudoscalar form factors from lattice QCD at the\n  physical point: We compute the nucleon axial and induced pseudoscalar form factors using\nthree ensembles of gauge configurations, generated with dynamical light quarks\nwith mass tuned to approximately their physical value. One of the ensembles\nalso includes the strange and charm quarks with their mass close to physical.\nThe latter ensemble has large statistics and finer lattice spacing and it is\nused to obtain final results, while the other two are used for assessing volume\neffects. The pseudoscalar form factor is also computed using these ensembles.\nWe examine the momentum dependence of these form factors as well as relations\nbased on pion pole dominance and the partially conserved axial-vector current\nhypothesis.",
        "positive": "Finite Temperature Phase Diagram of QCD with improved Wilson Fermions: We present results of an ongoing study of two flavour QCD with Wilson\nfermions at finite temperature. We have used tree level Symanzik improvement in\nboth the gauge and fermion part of the action. The phase diagram was previously\ndetermined on an $8^3 \\times 4$ lattice and the existence of Aoki's phase\ndemonstrated. On our current lattice of $12^2 \\times 24 \\times 4$ we have\nextended the set of observables and studied chiral and thermal properties at\nlight quark masses."
    },
    {
        "anchor": "Topological susceptibility in staggered fermion chiral perturbation\n  theory: The topological susceptibility of the vacuum in quantum chromodynamics has\nbeen simulated numerically using the Asqtad improved staggered fermion\nformalism. At nonzero lattice spacing the residual fermion doublers (fermion\n``tastes'') in the staggered fermion formalism give contributions to the\nsusceptibility that deviate from conventional continuum chiral perturbation\ntheory. In this brief report we estimate the taste-breaking artifact and\ncompare it with results of recent simulations, finding that it accounts for\nroughly half of the scaling violation.",
        "positive": "Neutron electric dipole moment using $N_f{=}2{+}1{+}1$ twisted mass\n  fermions: We evaluate the neutron electric dipole moment $\\vert \\vec{d}_N\\vert$ using\nlattice QCD techniques. The gauge configurations analyzed are produced by the\nEuropean Twisted Mass Collaboration using $N_f{=}2{+}1{+}1$ twisted mass\nfermions at one value of the lattice spacing of $a \\simeq 0.082 \\ {\\rm fm}$ and\na light quark mass corresponding to $m_{\\pi} \\simeq 373 \\ {\\rm MeV}$. Our\napproach to extract the neutron electric dipole moment is based on the\ncalculation of the $CP$-odd electromagnetic form factor $F_3(Q^2)$ for small\nvalues of the vacuum angle $\\theta$ in the limit of zero Euclidean momentum\ntransfer $Q^2$. The limit $Q^2 \\to 0$ is realized either by adopting a\nparameterization of the momentum dependence of $F_3(Q^2)$ and performing a fit,\nor by employing new position space methods, which involve the elimination of\nthe kinematical momentum factor in front of $F_3(Q^2)$. The computation in the\npresence of a $CP$-violating term requires the evaluation of the topological\ncharge ${\\cal Q}$. This is computed by applying the cooling technique and the\ngradient flow with three different actions, namely the Wilson, the Symanzik\ntree-level improved and the Iwasaki action. We demonstrate that cooling and\ngradient flow give equivalent results for the neutron electric dipole moment.\nOur analysis yields a value of $\\vert \\vec{d}_N\\vert=0.045(6)(1)\\ \\bar{\\theta}\n\\ e \\cdot {\\rm fm}$ for the ensemble with $m_\\pi=373$ MeV considered."
    },
    {
        "anchor": "Testing the efficiency of different improvement programs: We study the finite-size behaviour of a tree-level on-shell improved action\nfor the N-vector model. We present numerical results for N=3 and analytic\nresults in the large-N limit for the mass gap. We also report a perturbative\ncomputation at one loop of the mass gap for states of spatial momentum p. We\npresent a detailed comparison of the behaviour of this action with that of\nother formulations, including the perfect action, and a critical discussion of\nthe different approaches to the problem of action improvement.",
        "positive": "Determining F_pi from spectral sum rules: We derive spectral sum rules for a system with two quarks coupled to an\nimaginary isospin chemical potential in the \\epsilon regime. The sum rules show\nan explicit dependence on the pion decay constant which should make it possible\nto measure F_pi from the eigenvalue spectrum of this particular Dirac operator."
    },
    {
        "anchor": "Schwinger-Dyson equations in large-N quantum field theories and\n  nonlinear random processes: We propose a stochastic method for solving Schwinger-Dyson equations in\nlarge-N quantum field theories. Expectation values of single-trace operators\nare sampled by stationary probability distributions of the so-called nonlinear\nrandom processes. The set of all histories of such processes corresponds to the\nset of all planar diagrams in the perturbative expansions of the expectation\nvalues of singlet operators. We illustrate the method on the examples of the\nmatrix-valued scalar field theory and the Weingarten model of random planar\nsurfaces on the lattice. For theories with compact field variables, such as\nsigma-models or non-Abelian lattice gauge theories, the method does not\nconverge in the physically most interesting weak-coupling limit. In this case\none can absorb the divergences into a self-consistent redefinition of expansion\nparameters. Stochastic solution of the self-consistency conditions can be\nimplemented as a \"memory\" of the random process, so that some parameters of the\nprocess are estimated from its previous history. We illustrate this idea on the\nexample of two-dimensional O(N) sigma-model. Extension to non-Abelian lattice\ngauge theories is discussed.",
        "positive": "Mapping the Conformal Window: SU(2) with 4, 6 and 10 flavors of fermions: We present studies of the SU(2) gauge theory with 4, 6 and 10 fermion\nflavors. These models are expected to lie on both sides of the edge of the\nconformal window, where the theory has an infrared fixed point. We observe that\nthe coupling grows with the length scale at four flavors, implying QCD-like\nbehavior. At ten flavors the results are compatible with a Bank-Zaks type fixed\npoint. The results at six flavors remain inconclusive: the running is slow\ntowards the infrared but the range and accuracy of the study are insufficient\nfor determining the existence of a fixed point."
    },
    {
        "anchor": "The Chiral Magnetic Effect and chiral symmetry breaking in SU(3)\n  quenched lattice gauge theory: We study some properties of the non-Abelian vacuum induced by strong external\nmagnetic field. We perform calculations in the quenched SU(3) lattice gauge\ntheory with tadpole-improved Luscher-Weisz action and chirally invariant\nlattice Dirac operator. The following results are obtained: The chiral symmetry\nbreaking is enhanced by the magnetic field. The chiral condensate depends on\nthe strength of the applied field as a power function with exponent n = 1.6 +/-\n0.2. There is a paramagnetic polarization of the vacuum. The corresponding\nsusceptibility and other magnetic properties are calculated and compared with\nthe theoretical estimations. There are non-zero local fluctuations of the\nchirality and electromagnetic current, which grow with the magnetic field\nstrength. These fluctuations can be a manifestation of the Chiral Magnetic\nEffect (CME).",
        "positive": "The lattice gradient flow at tree-level and its improvement: The Yang-Mills gradient flow and the observable E(t), defined by the square\nof the field strength tensor at t>0, are calculated at finite lattice spacing\nand tree-level in the gauge coupling. Improvement of the flow, the gauge action\nand the observable are all considered. The results are relevant for two\npurposes. First, the discretization of the flow, gauge action and observable\ncan be chosen in such a way that $O(a^2)$, $O(a^4)$ or even $O(a^6)$\nimprovement is achieved. Second, simulation results using arbitrary\ndiscretizations can be tree-level improved by the perturbatively calculated\ncorrection factor normalized to one in the continuum limit."
    },
    {
        "anchor": "Lattice Simulation of Diquark Condensation in Dense Matter: We present results of a Monte Carlo simulation of a three dimensional\nGross-Neveu model with SU(2)xSU(2) chiral symmetry at non-zero baryon chemical\npotential mu, corresponding to non-zero baryon density. For mu sufficiently\nlarge there is a sharp transition between a phase where the chiral symmetry is\nbroken by a condensate <qbar q> and one where the global U(1) baryon number\nsymmetry appears to be broken by a scalar diquark condensate <qq>. There is\nalso tentative evidence for the formation of a weaker pseudoscalar diquark\ncondensate in the high density phase, which violoates parity.",
        "positive": "Topics in Light Hadron Mass Spectrum in Quenched QCD: Several topics concerning the light hadron spectrum are discussed. Flavor\nsymmetry breaking effects and the problem of quenched chiral logarithm are\nexamined with pion mass data for the Kogut-Susskind quark action, and light\nmeson decay constants for the Wilson action calculated with non-perturbative\nrenormalization constants are discussed. Results for quark masses are also\ngiven both for the Kogut-Susskind and Wilson actions."
    },
    {
        "anchor": "Quantum Critical Phenomena in an $O(4)$ Fermion Chain: We construct a fermionic lattice model containing interacting\nspin-$\\frac{1}{2}$ fermions with an $O(4)$ symmetry. In addition the model\ncontains a $\\mathbb{Z}_2$ chiral symmetry which prevents a fermion mass term.\nOur model is motivated by the ability to study its physics using the\nmeron-cluster algorithm. By adding a strong repulsive Hubbard interaction $U$,\nwe can transform it into the regular Heisenberg anti-ferromagnet. While we can\nstudy our model in any dimension, as a first project we study it in one spatial\ndimension. We discover that our model at $U=0$ can be described as a\nlattice-regularized 2-flavor Gross-Neveu model, where fermions become massive\nsince the $\\mathbb{Z}_2$ chiral symmetry of the model is spontaneously broken.\nWe show numerically that the theory remains massive when $U$ is small. At large\nvalues of $U$ the model is equivalent to the isotropic spin-half\nanti-ferromagnetic chain, which is massless for topological reasons. This\nimplies that our model has a quantum phase transition from a $\\mathbb{Z}_2$\nbroken massive phase to a topologically massless phase as we increase $U$. We\npresent results obtained from our quantum Monte Carlo method near this phase\ntransition.",
        "positive": "$\\mathcal{N}=1$ Supersymmetric SU(3) Gauge Theory with a Twist: We investigate the pure gauge sector of Super-QCD, i.e. Super-Yang-Mills\n(SYM) theory, with focus on the bound states. To improve chiral symmetry as\nwell as supersymmetry at finite lattice spacing, we use a deformed SYM lattice\naction. It contains a twist term, similar to the lattice formulation of twisted\nmass QCD. We present the status of our theoretical and numerical investigation."
    },
    {
        "anchor": "Imaginary chemical potential in QCD at finite temperature: After presenting a brief review of how simulations of QCD with imaginary\nchemical potential can be used to extract physical results, we analyse the\nphase structure of QCD with four flavours of dynamical fermions in the finite\ntemperature - imaginary chemical potential plane, and discuss perspectives for\nrealistic calculations.",
        "positive": "Lattice Computation of the Ghost Propagator in Linear Covariant Gauges: We discuss the subtleties concerning the lattice computation of the ghost\npropagator in linear covariant gauges, and present preliminary numerical\nresults."
    },
    {
        "anchor": "Topological flux sectors in extended U(1) gauge theory on T^4: We consider the 4d compact U(1) gauge theory with fundamental-adjoint action\non a hypertorus. We give a full characterization of the phase diagram of this\nmodel in terms of topological flux sectors.",
        "positive": "The extraction of the axial coupling from finite volume systems: The\n  long and short of it: Due to a pion-pole contribution, the nucleon axial current matrix elements\ncan be visualized in position space as becoming delocalized as the chiral limit\nis approached, with one-third of the current at distance of order the inverse\npion mass. However, this delocalization effect will not cause calculations of\nthe axial coupling in a finite system with standard boundary conditions\n(periodic for boson fields, antiperiodic for fermions) to have large finite\nvolume effects. This is seen by calculating axial coupling using a nonstandard\ncurrent with axial quantum numbers. The matrix elements of this new current\nlacks a pion pole and is not delocalized; however, its zero-momentum matrix\nelement is identical to that of the standard axial current both for infinite\nand finite volumes."
    },
    {
        "anchor": "Numerical study of the SU(2) Yang-Mills vacuum state: Much ado about\n  nothing?: Numerical results for relative weights of test gauge-field configurations in\nthe vacuum of the SU(2) lattice gauge theory in (3+1) dimensions are compared\nwith expectations following from various proposals for the Yang-Mills vacuum\nwave functional that interpolate between the free-field limit and the\ndimensional-reduction form.",
        "positive": "On the Definition of Gauge Field Operators in Lattice Gauge-Fixed\n  Theories: We address the problem of defining the gauge four-potential on the lattice,\nin terms of the natural link variables. Different regularized definitions are\nshown, through non perturbative numerical computation, to converge towards the\nsame continuum renormalized limit."
    },
    {
        "anchor": "The removal of critical slowing down: We present promising initial results of our adaptive multigrid solver\ndeveloped for application directly to the non-Hermitian Wilson-Dirac system in\n4 dimensions, as opposed to the solver developed in [1] for the corresponding\nnormal equations. The key behind the success of this algorithm is the use of an\nadaptive projection onto coarse grids that preserves the near null space of the\nsystem matrix. We demonstrate that the resulting algorithm has weak dependence\non the gauge coupling and exhibits extremely mild critical slowing down in the\nchiral limit.",
        "positive": "Anatomy of SU(3) flux tubes at finite temperature: An attempt to adapt the study of color flux tubes to the case of finite\ntemperature has been made. The field is measured both through the correlator of\ntwo Polyakov loops, one of which connected to a plaquette, and through a\nconnected correlator of Wilson loop and plaquette in the spatial sublattice.\nStill the profile of the flux tube resembles the transverse field distribution\naround an isolated vortex in an ordinary superconductor. The temperature\ndependence of all the parameters characterizing the flux tube is investigated."
    },
    {
        "anchor": "Non-perturbative renormalization and O$(a)$-improvement of the\n  non-singlet vector current with $N_{\\mathrm{f}}=2+1$ Wilson fermions and\n  tree-level Symanzik improved gauge action: In calculating hadronic contributions to precision observables for tests of\nthe Standard Model in lattice QCD, the electromagnetic current plays a central\nrole. Using a Wilson action with O($a$) improvement in QCD with\n$N_{\\mathrm{f}}$ flavors, a counterterm must be added to the vector current in\norder for its on-shell matrix elements to be O($a$) improved. In addition, the\nlocal vector current, which has support on one lattice site, must be\nrenormalized. At O($a$), the breaking of the SU($N_{\\mathrm{f}}$) symmetry by\nthe quark mass matrix leads to a mixing between the local currents of different\nquark flavors. We present a non-perturbative calculation of all the required\nimprovement and renormalization constants needed for the local and the\nconserved electromagnetic current in QCD with $N_{\\mathrm{f}}=2+1$\nO($a$)-improved Wilson fermions and tree-level Symanzik improved gauge action,\nwith the exception of one coefficient, which we show to be order $g_0^6$ in\nlattice perturbation theory. The method is based on the vector and axial Ward\nidentities imposed at finite lattice spacing and in the chiral limit. We make\nuse of lattice ensembles generated as part of the Coordinated Lattice\nSimulations (CLS) initiative.",
        "positive": "Studying the infrared region in Landau gauge QCD: We report on the progress we made in studying the infrared behavior of the\nghost and gluon dressing functions in Landau gauge. Related to this we also\ninvestigate a running coupling given in terms of those functions and compare\nour results to those coming from the Dyson-Schwinger approach. We present first\nnumerical results for the SU(3) ghost-ghost-gluon vertex renormalization\nconstant. In addition the spectrum of low-lying eigenvalues and eigenfunctions\nof the Faddeev-Popov operator is determined. The saturation of the ghost\npropagator in terms of those eigenvalues and eigenmodes is discussed at lower\nmomenta."
    },
    {
        "anchor": "Charmonium correlation and spectral functions at finite temperature: We study the properties of charmonium states at finite temperature in\nquenched QCD on isotropic lattices. We measured charmonium correlators using\nnon-perturbatively $\\cO(a)$ improved clover fermions on fine ($a=0.01$ fm)\nlattices with a relatively large size of $128^{3}\\times 96$, $128^3\\times48$,\n$128^3\\times32$ and $128^3\\times24$ at $0.73~T_c$, $1.46~T_c$, $2.20~T_c$ and\n$2.93~T_c$, respectively. Our analysis suggests that $\\Jpsi$ is melted already\nat $1.46~T_c$ and $\\eta_c$ starts to dissolve at $1.46~T_c$ and does not exist\nat higher temperatures. We also identify the heavy quark transport contribution\nat the spectral function level for the first time.",
        "positive": "Critical Three-Dimensional Ising Model on Spheriods from the Conformal\n  Bootstrap: We construct a conformal map from $\\mathbb{R}^3$ to a three-dimensional\nspheriod, which includes $\\mathbb{S}^3$, a double-cover of the 3-ball, and\n$\\mathbb{R} \\times \\mathbb{S}^2$ as limiting cases. Using the data of the\ncritical three-dimensional Ising model on $\\mathbb{R}^3$ that was computed\nusing the conformal bootstrap method, we numerically estimate the fourth-order\nBinder cumulant of the critical three-dimensional $\\phi^4$ theory on\n$\\mathbb{S}^3$. We expect this estimate will enable an interesting comparison\nbetween the conformal bootstrap and future calculations of critical $\\phi^4$\ntheory on $\\mathbb{S}^3$ using the Quantum Finite Element (QFE) method."
    },
    {
        "anchor": "A Strong-Coupling Analysis of the Lattice $CP^{N-1}$ Models in the\n  Presence of a $\u03b8$ Term: A $\\theta$ term, which couples to topological charge, is added to the lattice\n$CP^{N-1}$ model. The strong-coupling character expansion is developed. The\nseries for the free energy and mass gap are respectively computed to tenth\norder and fourth order. Several features of the strong-coupling analysis\nemerge. One is the loss of superconfinement. Another is that in the\nintermediate coupling constant region, there are indications of a transition to\na deconfining phase when $\\theta$ is sufficiently large. The transition is like\nthe one which has been observed in Monte Carlo simulations of a similar lattice\n$CP^{N-1}$ action.",
        "positive": "Study of Confinement Using the Schroedinger Functional: We use a gauge-invariant effective action defined in terms of the lattice\nSchroedinger functional to investigate vacuum dynamics and confinement in pure\nlattice gauge theories. After a brief introduction to the method, we report\nsome numerical results."
    },
    {
        "anchor": "Static potential and local color fields in unquenched lattice QCD$_3$: String breaking by dynamical quarks in three-dimensional lattice QCD is\nanalyzed through measurements of the potential and the local color-electric\nfield strength generated by a static quark-antiquark pair. Simulations were\ndone for unquenched SU(2) color with two flavors of staggered light quarks. An\nimproved gluon action was used, which allows simulations to be done on coarse\nlattices, providing an extremely efficient means to access the large quark\nseparations and long propagation times at which string breaking occurs. The\nstatic sources were generated using Wilson loop operators, hence no light\nvalence quarks are present in the resulting trial states. Results give\nunambiguous evidence of string breaking. First the static potential is shown to\nsaturate at twice the heavy-light meson mass at large separations. Then it is\ndemonstrated that the local color-electric field strength in the region between\nthe heavy quarks tends towards vacuum values at large separations, the first\ntime that this most graphic effect of quark vacuum polarization on the\nconfining flux-tube has been realized in lattice QCD. Implications of these\nresults for unquenched simulations of four-dimensional QCD are drawn.",
        "positive": "Hidden Conformal Symmetry from the Lattice: We analyze newly expanded and refined data from lattice studies of an SU(3)\ngauge theory with eight Dirac fermions in the fundamental representation. We\nfocus on the light composite states emerging from these studies, consisting of\na set of pseudoscalars and a single light scalar. We first consider the view\nthat this theory is just outside the conformal window. In this case, the\npseudoscalars arise from spontaneous breaking of chiral symmetry. Identifying\nthe scalar in this case as an approximate dilaton, we fit the lattice data to a\ndilaton effective field theory, finding that it yields a good fit even at\nlowest order. For comparison, we then consider the possibility that the theory\nis inside the conformal window. The fermion mass provides a deformation,\ntriggering confinement. We employ simple scaling laws to fit the lattice data,\nand find that it is of lesser quality."
    },
    {
        "anchor": "Continuum limit of field theories regularized on a random lattice: The continuum limit and scaling properties of an asymptotically free field\ntheory regularized on a random lattice are compared with those on a regular\nsquare lattice. We work on random lattices parametrized by a degree of\n``randomness'' $\\kappa$. We show that the continuum limit exists and different\n$\\kappa$ are related by a finite renormalization.",
        "positive": "Strange and charmed baryons using N_f=2 twisted mass QCD: We compute the mass spectrum for strange/charmed baryons in the partially\nquenched approach using N_f=2 twisted mass QCD configurations. We investigate\ntwo main issues: the size of lattice artefacts using three values of the\nlattice spacing (the smallest of which is approximately 0.05 fm) and the\ndependence of baryon masses on meson (or quark) masses. We thus perform a\nglobal fit in order to extrapolate simultaneously to the continuum limit and to\nthe physical point. We estimate the masses of Omega_{sss}, Xi_{dss},\nLambda_{uds}, Omega_{ccc}, Xi_{dcc}, Lambda_{udc}."
    },
    {
        "anchor": "2-flavour $SU(2)$ gauge theory with exponential clover Wilson fermions: Composite Higgs models are a class of models proposed to address the\nhierarchy and naturalness problems associated with the Standard Model\nfundamental scalar Higgs. $SU(2)$ with two fundamental flavours is a minimal\nmodel for the composite Higgs sector which is not yet ruled out by experimental\ndata. We present lattice results for $SU(2)$ with two fundamental mass\ndegenerate flavours. For the fermion action we use the new exponential clover\nWilson fermion action, which offers $O(a)$ improvement. We discuss tuning the\n$c_{\\mathrm{SW}}$ parameter through Schr\\\"{o}dinger functional simulations, the\nscale setting of the ensembles using the Wilson gauge flow, and the low energy\nspectroscopy of the theory including the masses of the pseudoscalar isotriplet\nGoldstone bosons and the vector isotriplet.",
        "positive": "Nonperturbative infrared fixed point in sextet QCD: The SU(3) gauge theory with fermions in the sextet representation is one of\nseveral theories of interest for technicolor models. We have carried out a\nSchrodinger functional (SF) calculation for the lattice theory with two flavors\nof Wilson fermions. We find that the discrete beta function changes sign when\nthe SF renormalized coupling is in the neighborhood of g^2 = 2.0, showing a\nbreakdown of the perturbative picture even though the coupling is weak. The\nmost straightforward interpretation is an infrared-stable fixed point."
    },
    {
        "anchor": "Radiative transition decay width of\n  $\u03c8_2(3823)\\rightarrow\u03b3\u03c7_{c1}$ from lattice QCD: We present an exploratory $N_f=2$ lattice QCD study of $\\psi_2(3823)\\to\n\\gamma \\chi_{c1}$ at a pion mass $m_{\\pi}\\approx 350$~MeV. The related\ntwo-point and three-piont functions are calculated using the distillation\nmethod. The electromagnetic multipole form factor $\\hat{V}(0)=2.083(11)$ for\n$J/\\psi\\to\\gamma \\eta_c$ is consistent with previous lattice results, the form\nfactors $\\hat{E}_1(0)$, $\\hat{M}_2(0)$ and $\\hat{E}_3(0)$ for\n$\\Gamma(\\chi_{c2}\\to\\gamma J/\\psi)$ have the same hierarchy as that derived\nfrom experiments and the predicted decay width $\\Gamma(\\chi_{c2}\\to\\gamma\nJ/\\psi)=368(5)~\\text{keV}$ is in excellent agreement with the PDG value\n$374(10)~\\text{keV}$ and previous lattice QCD results in the quenched\napproximation. The same strategy is applied to the study of the process\n$\\psi_2(3823)\\to \\gamma \\chi_{c1}$ and the partial decay width is predicted to\nbe $337(27)~\\text{keV}$. According to the BESIII constraints on the\n$\\psi_2(3823)$ decay channels and some phenomenological results, we estimate\nthe total width $\\Gamma(\\psi_2(3823))=520(100)~\\text{keV}$.",
        "positive": "Non-perturbative improvement of quark mass renormalization in\n  two-flavour lattice QCD: We non-perturbatively determine the renormalization constant and the\nimprovement coefficients relating the renormalized current and subtracted quark\nmass in O(a) improved two-flavour lattice QCD. We employ the Schr\\\"odinger\nfunctional scheme and fix the physical extent of the box by working at a\nconstant value of the renormalized coupling. Our calculation yields results\nwhich cover two regions of bare parameter space. One is the weak-coupling\nregion suitable for volumes of about half a fermi. By making simulations in\nthis region, quarks as heavy as the bottom can be propagated with the full\nrelativistic QCD action and renormalization problems in HQET can be solved\nnon-perturbatively by a matching to QCD in finite volume. The other region\nrefers to the common parameter range in large-volume simulations of two-flavour\nlattice QCD, where our results have particular relevance for charm physics\napplications."
    },
    {
        "anchor": "Tests of the continuum limit for the $SO(4)$ Principal Chiral Model and\n  the prediction for $\u0141_\\MS$: We investigate the continuum limit in $SO(N)$ Principal Chiral Models\nconcentrating in detail on the $SO(4)$ model and its covering group\nSU(2)xSU(2). We compute the mass gap in terms of Lambda_MS and compare with the\nprediction of Hollowood of $m/\\L_\\MS = 3.8716$. We use the finite-size scaling\nmethod of L\\\"uscher et al. to deduce $m/\\L_\\MS$ and find that for the $SO(4)$\nmodel the computed result of $m/\\L_\\MS \\sim 14$ is in strong disagreement with\ntheory but that a similar analysis of the SU(2)xSU(2) yields excellent\nagreement with theory. We conjecture that for $SO(4)$ violations of the\nfinite-size scaling assumption are severe forthe values of the correlation\nlength, $\\xi$, investigated and that our attempts to extrapolate the results to\nzero lattice spacing, although plausible, are erroneous. Conversely, the\nfinite-size scaling violations in the SU(2)xSU(2) simulation are consistent\nwith perturbation theory and the computed $beta-$function agrees well with the\n3-loop approximation for couplings evaluated at scales $L/a \\le \\xi$, where\n$\\xi$ is measured in units of the lattice spacing, $a$. We conjecture that\nlattice vortex artifacts in the $SO(4)$ model are responsible for delaying the\nonset of the continuum limit until much larger correlation lengths are achieved\nnotwithstanding the apparent onset of scaling. Results for the mass spectrum\nfor SO(N) m, N=8,10 are given whose comparison with theory gives plausible\nsupport to our ideas.",
        "positive": "Resolution of the Landau pole problem in QED: We present new numerical results for the renormalized mass and coupling in\nnon-compact lattice QED with staggered fermions. Implications for the continuum\nlimit and the role of the Landau pole are discussed."
    },
    {
        "anchor": "Gauge theory of Lorentz group on the lattice: The model with the fermions coupled in the non - minimal way to the gauge\ntheory of Lorentz group is considered. The lattice regularization is suggested.\nIt is argued that this model may exist in the phase with broken chiral symmetry\nand without confinement. We speculate about the possibility that this\nconstruction may serve as an origin of the dynamical electroweak symmetry\nbreaking.",
        "positive": "The deconfinement transition in SU(N) gauge theories: We investigate the properties of the deconfinement transition in SU(4) and\nSU(6) gauge theories. We find that it is a `normal' first order transition in\nboth cases, from which we conclude that the transition is first order in the\nN->infinity limit. Comparing our preliminary estimates of the continuum values\nof Tc/sqrt(K) with existing values for SU(2) and SU(3) demonstrates a weak\ndependence on N for all values of N."
    },
    {
        "anchor": "Investigation of the Second Moment of the Nucleon's g1 and g2 Structure\n  Functions in Two-Flavor Lattice QCD: The reduced matrix elements a_2 and d_2 are computed in lattice QCD with\nN_f=2 flavors of light dynamical (sea) quarks. For proton and neutron targets\nwe obtain as our best estimates d_2^(p)=0.004(5) and d_2^(n)=-0.001(3),\nrespectively, in the MSbar scheme at Q^2=5 GeV^2, while for a_2 we find\na_2^(p)=0.077(12) and a_2^(n)=-0.005(5), where the errors are purely\nstatistical.",
        "positive": "B meson excitations with chirally improved light quarks: We present our latest results for the excitations of static-light mesons on\nboth quenched and unquenched lattices, where the light quarks are simulated\nusing the chirally improved (CI) lattice Dirac operator."
    },
    {
        "anchor": "SU(3) flavour breaking and baryon structure: We present results from the QCDSF/UKQCD collaboration for hyperon\nelectromagnetic form factors and axial charges obtained from simulations using\nNf=2+1 flavours of O(a)-improved Wilson fermions. We also consider matrix\nelements relevant for hyperon semileptonic decays. We find flavour-breaking\neffects in hyperon magnetic moments which are consistent with experiment, while\nour results for the connected quark spin content indicates that quarks\ncontribute more to the spin of the Xi baryon than they do to the proton.",
        "positive": "The Pseudo Specific Heat in SU(2) Gauge Theory : Finite Size Dependence\n  and Finite Temperature Effects: We investigate the pseudo specific heat of SU(2) gauge theory near the\ncrossover point on $4^4$ to $16^4$ lattices. Several different methods are used\nto determine the specific heat. The curious finite size dependence of the peak\nmaximum is explained from the interplay of the crossover phenomenon with the\ndeconfinement transition occurring due to the finite extension of the lattice.\nWe find, that for lattices of size $8^4$ and larger the crossover peak is\nindependent of lattice size at $\\beta_{co}=2.23(2)$ and has a peak height of\n$C_{V,co}=1.685(10)$. We conclude therefore that the crossover peak is not the\nresult of an ordinary phase transition. Further, the contributions to $C_V$\nfrom different plaquette correlations are calculated. We find, that at the peak\nand far outside the peak the ratio of contributions from orthogonal and\nparallel plaquette correlations is different. To estimate the finite\ntemperature influence on symmetric lattices far off the deconfinement\ntransition point we calculate the modulus of the lattice average of the\nPolyakov loop on these lattices and compare it to predictions from a random\nwalk model."
    },
    {
        "anchor": "Probing the energy-smeared R-ratio on the lattice: We present a first-principles lattice QCD investigation of the $R$-ratio\nbetween the $e^+e^-$ cross-section into hadrons and that into muons. By using\nthe method of Ref.[1], that allows to extract smeared spectral densities from\nEuclidean correlators, we compute the $R$-ratio convoluted with Gaussian\nsmearing kernels of widths of about $600$ MeV and central energies from $220$\nMeV up to $2.5$ GeV. Our theoretical results are compared with the\ncorresponding quantities obtained by smearing the KNT19 compilation [2] of\n$R$-ratio experimental measurements with the same kernels and, by centring the\nGaussians in the region around the $\\rho$-resonance peak, a tension of about\nthree standard deviations is observed. From the phenomenological perspective,\nwe have not included yet in our calculation QED and strong isospin-breaking\ncorrections and this might affect the observed tension. From the methodological\nperspective, our calculation demonstrates that it is possible to study the\n$R$-ratio in Gaussian energy bins on the lattice at the level of accuracy\nrequired in order to perform precision tests of the Standard Model.",
        "positive": "Low--Temperature Series for Renormalized Operators: the Ferromagnetic\n  Square--Lattice Ising Model.: A method for computing low--temperature series for renormalized operators in\nthe two--dimensional Ising model is proposed. These series are applied to the\nstudy of the properties of the truncated renormalized Hamiltonians when we\nstart at very low temperature and zero field. The truncated Hamiltonians for\nmajority rule, Kadanoff transformation and decimation for $2 \\times 2$ blocks\ndepend on the how we approach the first--order phase--transition line. These\nRenormalization Group transformations are multi--valued and discontinuous at\nthis first--order transition line when restricted to some finite--dimensional\ninteraction space."
    },
    {
        "anchor": "Z(3) Symmetric Dimensional Reduction of (2+1)D QCD: Here we present a candidate for a Z(3)-symmetric reduced action for the\ndescription of the (2+1)D SU(3) gauge theory",
        "positive": "Chiral Lattice Fermions, Minimal Doubling, and the Axial Anomaly: Exact chiral symmetry at finite lattice spacing would preclude the axial\nanomaly. In order to describe a continuum quantum field theory of Dirac\nfermions, lattice actions with purported exact chiral symmetry must break the\nflavor-singlet axial symmetry. We demonstrate that this is indeed the case by\nusing a minimally doubled fermion action. For simplicity we consider the\nAbelian axial anomaly in two dimensions. At finite lattice spacing and with\ngauge interactions, the axial anomaly arises from non-conservation of the\nflavor-singlet current. Similar non-conservation also leads to the axial\nanomaly in the case of the naive lattice action. For minimally doubled actions,\nhowever, fine tuning of the action and axial current is necessary to arrive at\nthe anomaly. Conservation of the flavor non-singlet vector current additionally\nrequires the current to be fine tuned. Finally we determine that the chiral\nprojection of a minimally doubled fermion action can be used to arrive at a\nlattice theory with an undoubled Dirac fermion possessing the correct anomaly\nin the continuum limit."
    },
    {
        "anchor": "Multi-Pion States in Lattice QCD and the Charged-Pion Condensate: The ground-state energies of systems containing up to twelve $\\pi^+$'s in a\nspatial volume V ~ (2.5 fm)^3 are computed in dynamical, mixed-action lattice\nQCD at a lattice spacing of ~ 0.125 fm for four different values of the light\nquark masses. Clean signals are seen for each ground state, allowing for a\nprecise extraction of both the $\\pi^+\\pi^+$ scattering length and\n$\\pi^+\\pi^+\\pi^+$-interaction from a correlated analysis of systems containing\ndifferent numbers of $\\pi^+$'s. This extraction of the $\\pi^+\\pi^+$ scattering\nlength is consistent with than that from the $\\pi^+\\pi^+$-system alone. The\nlarge number of systems studied here significantly strengthens the arguments\npresented in our earlier work and unambiguously demonstrates the presence of a\nlow energy $\\pi^+\\pi^+\\pi^+$-interaction. The equation of state of a $\\pi^+$\ngas is investigated using our numerical results and the density dependence of\nthe isospin chemical potential for these systems agrees well with the\ntheoretical expectations of leading order chiral perturbation theory. The\nchemical potential is found to receive a substantial contribution from the\n$\\pi^+\\pi^+\\pi^+$-interaction at the lighter pion masses. An important\ntechnical aspect of this work is the demonstration of the necessity of\nperforming propagator contractions in greater than double precision to extract\nthe correct results.",
        "positive": "Cold, dense matter via the lattice NJL model: We simulate the lattice Nambu--Jona-Lasinio (NJL) model in 3+1-dimensions at\nnon-zero baryon chemical potential (mu) and zero temperature (T) and treat the\nresults as phenomenologically relevant for cold, dense quark matter.\nMeasurements of the chiral condensate indicate a crossover in the thermodynamic\nlimit, whilst at high chemical potential and zero temperature we observe a\nnon-zero diquark condensate and a gap in the fermion dispersion relation, which\ntogether provide evidence for BCS superfluidity. In particular, the size of gap\nis found to be approximately 15% the value of the vacuum fermion mass and\nroughly independent of mu in the chirally restored phase."
    },
    {
        "anchor": "A simple method to optimize HMC performance: We present a practical strategy to optimize a set of Hybrid Monte Carlo\nparameters in simulations of QCD and QCD-like theories. We specialize to the\ncase of mass-preconditioning, with multiple time-step Omelyan integrators.\nStarting from properties of the shadow Hamiltonian we show how the optimal\nsetup for the integrator can be chosen once the forces and their variances are\nmeasured, assuming that those only depend on the mass-preconditioning\nparameter.",
        "positive": "Semileptonic $B \\to D^{**}$ decays in Lattice QCD : a feasibility study\n  and first results: We compute the decays ${B\\to D^\\ast_0}$ and ${B\\to D^\\ast_2}$ with finite\nmasses for the $b$ and $c$ quarks. We first discuss the spectral properties of\nboth the $B$ meson as a function of its momentum and of the $D^\\ast_0$ and\n$D^\\ast_2$ at rest. We compute the theoretical formulae leading to the decay\namplitudes from the three-point and two-point correlators. We then compute the\namplitudes at zero recoil of ${B\\to D^\\ast_0}$ which turns out not to be\nvanishing contrary to what happens in the heavy quark limit. This opens a\npossibility to get a better agreement with experiment. To improve the continuum\nlimit we have added a set of data with smaller lattice spacing. The ${B\\to\nD^\\ast_2}$ vanishes at zero recoil and we show a convincing signal but only\nslightly more than 1 sigma from 0. In order to reach quantitatively significant\nresults, we plan to fully exploit smaller lattice spacings as well as another\nlattice regularization."
    },
    {
        "anchor": "Spin Polarized Non-Relativistic Fermions in 1+1 Dimensions: We study by Monte Carlo methods the thermodynamics of a spin polarized gas of\nnon-relativistic fermions in 1+1 dimensions. The main result of this work is\nthat our action suffers no significant sign problem for any spin polarization\nin the region relevant for dilute degenerate fermi gases. This lack of sign\nproblem allows us to study attractive spin polarized fermions\nnon-perturbatively at spin polarizations not previously explored. For some\nparameters values we verify results previously obtained by methods which\ninclude an uncontrolled step like complex Langevin and/or analytical\ncontinuation from imaginary chemical potential. For others, larger values of\nthe polarization, we deviate from these previous results.",
        "positive": "Vortices, monopoles and confinement: We construct the creation operator of a vortex using the methods developed\nfor monopoles. The vacuum expectation value of this operator is interpreted as\na disorder parameter describing vortex condensation and is studied numerically\non a lattice in SU(2) gauge theory. The result is that vortices behave in the\nvacuum in a similar way to monopoles. The disorder parameter is different from\nzero in the confined phase, and vanishes at the deconfining phase transition.\nWe discuss this behaviour in terms of symmetry. Correlation functions of the\nvortex creation operator at zero temperature are also investigated. A\ncomparison is made with related results by other groups."
    },
    {
        "anchor": "Interpolating the Free Energy Density Differences of Reweighting Methods: A discussion of the overlap problem of reweighting approaches to evaluating\ncritical phenomenon in fermionic systems is motivated by highlighting the\ndivergence of the joint probability density function of a general ratio. By\nidentifying the bounds for which this integral can be expressed in closed form,\nwe establish criteria for accurately mapping the joint ratio distribution of\ntwo disjoint ensembles through interpolation. The approach is applied to QCD\nwith four staggered flavours to evaluate the critical line in the $\\beta-\\mu$\nplane.",
        "positive": "Non-perturbative renormalization of lattice operators in coordinate\n  space: We present the first numerical implementation of a non-perturbative\nrenormalization method for lattice operators, based on the study of correlation\nfunctions in coordinate space at short Euclidean distance. The method is\napplied to compute the renormalization constants of bilinear quark operators\nfor the non-perturbative O(a)-improved Wilson action in the quenched\napproximation. The matching with perturbative schemes, such as MS-bar, is\ncomputed at the next-to-leading order in continuum perturbation theory. A\nfeasibility study of this technique with Neuberger fermions is also presented."
    },
    {
        "anchor": "A new lattice measurement for potentials between static SU(3) sources: In this article, a new calculation of static potentials between sources of\ndifferent representations in SU(3) gauge group is presented. The results of\nauthor's previous study \\cite{Deld00} at the smallest lattice spacing\n$a_{s}\\simeq0.11$~ fm are shown to have been affected by finite volume effects.\nWithin statistical errors, the new results obtained here are still in agreement\nwith both, Casimir scaling and flux tube counting. There is also no\ncontradiction to the results obtained in Ref.~ \\cite{Bali00} which however\nexclude flux counting.",
        "positive": "Absence of vortex condensation in a two dimensional fermionic XY model: Motivated by a puzzle in the study of two dimensional lattice Quantum\nElectrodynamics with staggered fermions, we construct a two dimensional\nfermionic model with a global U(1) symmetry. Our model can be mapped into a\nmodel of closed packed dimers and plaquettes. Although the model has the same\nsymmetries as the XY model, we show numerically that the model lacks the well\nknown Kosterlitz-Thouless phase transition. The model is always in the gapless\nphase showing the absence of a phase with vortex condensation. In other words\nthe low energy physics is described by a non-compact U(1) field theory. We show\nthat by introducing an even number of layers one can introduce vortex\ncondensation within the model and thus also induce a KT transition."
    },
    {
        "anchor": "Monopole creation operators as confinement--deconfinement order\n  parameters: We study numerically two versions of the monopole creation operators proposed\nby Frohlich and Marchetti. The disadvantage of the old version of the monopole\ncreation operator is due to visibility of the Dirac string entering the\ndefinition of the creation operator in the theories with coexisting electric\nand magnetic charges. This problem does not exist for the new creation operator\nwhich is rather complicated. Using the Abelian Higgs model with a compact gauge\nfield we show that both definitions of the monopole creation operator can serve\nas order parameters for the confinement--deconfinement phase transition. The\nvalue of the monopole condensate for the old version depends on the length of\nDirac string. However, as soon as the length is fixed the old operator\ncertainly discriminates between the phases with condensed and non--condensed\nmonopoles.",
        "positive": "Charm annihilation effects on the hyperfine splitting in charmonium: In calculations of the hyperfine splitting in charmonium, the contributions\nof the disconnected diagrams are considered small and are typically ignored. We\naim to estimate nonperturbatively the size of the resulting correction, which\nmay eventually be needed in high precision calculations of the charmonium\nspectrum. We study this problem in the quenched and unquenched QCD cases. On\ndynamical ensembles the disconnected charmonium propagators contain light modes\nwhich complicate the extraction of the signal at large distances. In the fully\nquenched case, where there are no such light modes, the interpretation of the\nsignal is simplified. We present results from lattices with $a\\approx 0.09$ fm\nand $a\\approx 0.06$ fm."
    },
    {
        "anchor": "$\u03b8$ dependence of $T_c$ in 4d SU(3) Yang-Mills theory with\n  histogram method and the Lee-Yang zeros in the large $N$ limit: The phase diagram on the $\\theta$-$T$ plane in four dimensional SU(3)\nYang-Mills theory is explored. We revisit the $\\theta$ dependence of the\ndeconfinement transition temperature, $T_c(\\theta)$, on the lattice through the\nconstraint effective potential for Polyakov loop. The $\\theta$ term is\nintroduced by the reweighting method, and the critical $\\beta$ is determined to\n$\\theta \\sim 0.75$, where the interpolation in $\\beta$ is carried out by the\nmultipoint reweighting method. The $\\theta$ dependence of $T_c$ obtained here\nturns out to be consistent with the previous result by D'Elia and Negro\n\\cite{DElia:2012pvq,DElia:2013uaf}. We also derive $T_c(\\theta)$ by classifying\nconfigurations into the high and low temperature phases and applying the\nClausius-Clapeyron equation. It is found that the potential barrier in the\ndouble well potential at $T_c(\\theta)$ becomes higher with $\\theta$, which\nsuggests that the first order transition continues robustly above $\\theta \\sim\n0.75$. Using information obtained here, we try to depict the expected $\\theta$\ndependence of the free energy density at $T < T_c(0)$, which crosses the first\norder transition line at an intermediate value of $\\theta$. Finally, how the\nLee-Yang zeros associated with the spontaneous CP violation appear is discussed\nformally in the large $N$ limit, and the locations of them are found to be\n$(\\theta_R,\\theta_I)=\\left( (2m+1)\\pi, \\frac{2n+1}{2\\chi V_4} \\right)$ with $n$\nand $m$ arbitrary integers.",
        "positive": "Investigations of QCD at non-zero isospin density: We investigate the QCD phase diagram as a function of isospin chemical\npotential at a fixed temperature by directly putting large numbers of \\pi^+s\ninto the system. Correlation functions of N \\pi^+s systems involves N!N!\ncontractions, and become extremely expensive when N is large. In order to\nalleviate this problem, a recursion relation of correlation functions has been\nderived in Ref. [1] that substantially reduces the number of independent\ncontractions needed and makes the study of many pions systems be possible. In\nthis proceeding this method is investigated numerically. We have also\nconstructed a new method that is even more efficient, enabling us to study\nsystems of up to 72 \\pi^+s."
    },
    {
        "anchor": "Relativistic $N$-particle energy shift in finite volume: We present a general method for deriving the energy shift of an interacting\nsystem of $N$ spinless particles in a finite volume. To this end, we use the\nnonrelativistic effective field theory (NREFT), and match the pertinent\nlow-energy constants to the scattering amplitudes. Relativistic corrections are\nexplicitly included up to a given order in the $1/L$ expansion. We apply this\nmethod to obtain the ground state of $N$ particles, and the first excited state\nof two and three particles to order $L^{-6}$ in terms of the threshold\nparameters of the two- and three-particle relativistic scattering amplitudes.\nWe use these expressions to analyze the $N$-particle ground state energy shift\nin the complex $\\varphi^4$ theory.",
        "positive": "Numerical study of chiral magnetic effect in quenched SU(2) lattice\n  gauge theory: A possible experimental observation of the chiral magnetic effect in heavy\nion collisions at RHIC was recently reported by the STAR Collaboration. We\nstudy signatures of this effect in SU(2) lattice gluodynamics with the chirally\ninvariant Dirac operator. We find that at zero temperature the local\nfluctuations of an electric current of quarks and chirality fluctuations\nincrease with external Abelian magnetic field. The external magnetic field\nleads to spatial separation of the quark's electric charges. The separation\nincreases with the strength of the magnetic field. As temperature gets higher\nthe dependence of these quantities on the strength of the magnetic field\nbecomes weaker. In the deconfinement phase the local fluctuations of the chiral\ndensity and of the spatial components of the quarks electric current are large\nand are almost independent on the external magnetic field. The local\nfluctuations of the electric charge density decrease with the strength of the\nmagnetic field in this phase."
    },
    {
        "anchor": "Low-Lying Dirac Eigenmodes, Topological Charge Fluctuations and the\n  Instanton Liquid Model: The local structure of low-lying eigenmodes of the overlap Dirac operator is\nstudied. It is found that these modes cannot be described as linear\ncombinations of 't Hooft \"would-be\" zeromodes associated with instanton\nexcitations that underly the Instanton Liquid Model. This implies that the\ninstanton liquid scenario for spontaneous chiral symmetry breaking in QCD is\nnot accurate. More generally, our data suggests that the vacuum fluctuations of\ntopological charge are not effectively dominated by localized lumps of unit\ncharge with which the topological \"would-be\" zeromodes could be associated.",
        "positive": "Large-$N$ limit of the gradient flow in the 2D $O(N)$ nonlinear sigma\n  model: The gradient flow equation in the 2D $O(N)$ nonlinear sigma model with\nlattice regularization is solved in the leading order of the $1/N$ expansion.\nBy using this solution, we analytically compute the thermal expectation value\nof a lattice energy--momentum tensor defined through the gradient flow. The\nexpectation value reproduces thermodynamic quantities obtained by the standard\nlarge-$N$ method. This analysis confirms that the above lattice\nenergy--momentum tensor restores the correct normalization automatically in the\ncontinuum limit, in a system with a non-perturbative mass gap."
    },
    {
        "anchor": "Development of Lattice QCD Tool Kit on Cell Broadband Engine Processor: We report an implementation of a code for SU(3) matrix multiplication on\nCell/B.E., which is a part of our project, Lattice Tool Kit on Cell/B.E.. On\nQS20, the speed of the matrix multiplication on SPE in single precision is\n227GFLOPS and it becomes 20GFLOPS {this vaule was remeasured and corrcted.}\ntogether with data transfer from main memory by DNA transfer, which is 4.6% of\nthe hardware peak speed (460GFLOPS), and is 7.4% of the theoretical peak speed\nof this calculation (268.77GFLOPS). We briefly describe our tuning procedure.",
        "positive": "Infra-red divergences in the large-N expansion: We investigate a vectorial O(N) model with a generic nearest-neighbor\ninteraction W(\\bsigma_i\\cdot \\bsigma_j) (depending on {\\cal N} tunable\nparameters), a Yukawa (and Gross Neveu) model with N_f fermions at finite\ntemperature and the vectorial \\phi^6 model, in the large N (N_f) limit. All\nthis models exhibit a Mean Field critical point for N=\\infinity. When 1/N\nfluctuations are included, infra red divergences appear near the critical\npoint. In the framework of a generalized 1/N expansion we show that these\ndivergences are related to a universal crossover mechanism between the Mean\nField universality class (N=\\infinity) and the nonclassical one for\nN<\\infinity. For the generic nearest-neighbor interaction multicritical points\nare also investigated."
    },
    {
        "anchor": "Algebraic Techniques for Enumerating Self-Avoiding Walks on the Square\n  Lattice: We describe a new algebraic technique for enumerating self-avoiding walks on\nthe rectangular lattice. The computational complexity of enumerating walks of\n$N$ steps is of order $3^{N/4}$ times a polynomial in $N$, and so the approach\nis greatly superior to direct counting techniques. We have enumerated walks of\nup to 39 steps. As a consequence, we are able to accurately estimate the\ncritical point, critical exponent, and critical amplitude.",
        "positive": "Cost of QCD simulations with n_f=2 dynamical Wilson fermions: Cost estimates for simulations of full QCD with n_f=2 Wilson fermions by\nhybrid Monte Carlo are presented. The extrapolations are based on the average\nnumber of iterations of the iterative solver within the fermionic part of the\nHMC molecular dynamics, which is closely related to the minimal eigenvalue of\nM^+M The cost formula is determined as a product of the scaling functions of\niterative solver and integrated autocorrelation time as function of the inverse\nlattice pseudoscalar mass. Timings by SESAM/TxL allow to fix the pre-factor. It\nis demonstrated that a 2-flavor dynamical determination of light hadron masses\nwith a statistical precision comparable to the corresponding quenched results\nfrom CP-PACS can be an appropriate task for a 100 Tflops system."
    },
    {
        "anchor": "Looking for the Logarithms in Four-Dimensional Nambu-Jona-Lasinio Models: We study the problem of triviality in the four dimensional Nambu-Jona-Lasinio\nmodel with discrete chiral symmetry using both large-N expansions and lattice\nsimulations. We find that logarithmic corrections to scaling appear in the\nequation of state as predicted by the large-N expansion. The data from $16^4$\nlattice simulations is sufficiently accurate to distinguish logarithmically\ntrivial scaling from power law scaling. Simulations on different lattice sizes\nreveal an interesting interplay of finite size effects and triviality. We argue\nthat such effects are qualitatively different for theories based on fundamental\nscalar rather than fermion fields. Several lessons learned here can be applied\nto simulations and analyses of more challenging field theories.",
        "positive": "Absence of Chiral Fermions in the Eichten--Preskill Model: The model proposed by Eichten and Preskill for obtaining theories with chiral\nfermions from the lattice is shown to undergo spontaneous symmetry breaking. In\naddition, the fermions appear to be Dirac-like everywhere in the phase diagram\nwith no room for undoubled Weyl fermions. The phase diagram of a closely\nrelated Higgs-Yukawa model is similar to that of the Smit--Swift model, which\nalso does not give rise to chiral fermions. These results cast serious doubts\non the original scenario for the emergence of chiral fermions."
    },
    {
        "anchor": "2+1 flavor domain wall QCD on a (2 fm)^3 lattice: light meson\n  spectroscopy with Ls = 16: We present results for light meson masses and pseudoscalar decay constants\nfrom the first of a series of lattice calculations with 2+1 dynamical flavors\nof domain wall fermions and the Iwasaki gauge action. The work reported here\nwas done at a fixed lattice spacing of about 0.12 fm on a 16^3\\times32 lattice,\nwhich amounts to a spatial volume of (2 fm)^3 in physical units. The number of\nsites in the fifth dimension is 16, which gives m_{res} = 0.00308(4) in these\nsimulations. Three values of input light sea quark masses, m_l^{sea} \\approx\n0.85 m_s, 0.59 m_s and 0.33 m_s were used to allow for extrapolations to the\nphysical light quark limit, whilst the heavier sea quark mass was fixed to\napproximately the physical strange quark mass m_s. The exact rational hybrid\nMonte Carlo algorithm was used to evaluate the fractional powers of the fermion\ndeterminants in the ensemble generation. We have found that f_\\pi = 127(4) MeV,\nf_K = 157(5) MeV and f_K/f_\\pi = 1.24(2), where the errors are statistical\nonly, which are in good agreement with the experimental values.",
        "positive": "Spectra of Lattice Dirac Operators in Non-Trivial Topology Backgrounds: Dirac operators in non-trivial topology backgrounds in a finite box are\nreviewed. We analyze how the formalism translates to the lattice, with special\nemphasis on uniform field backgrounds."
    },
    {
        "anchor": "Axial U(1) symmetry in the chiral symmetric phase of 2-flavor QCD at\n  finite temperature: We discuss the fate of the axial U(1) symmetry in 2-flavor QCD at finite\ntemperature, where the non-singlet chiral symmetry is restored. We first\nsummarize the previous theoretical investigation on the relation between the\neigenvalue density of the Dirac operator and the axial U(1) symmetry. We show\nthat the eigenvalue density near the origin behaves as $\\lambda^\\gamma$ with\n$\\gamma > 2$ in the chirally symmetric phase, where $\\lambda$ is an eigenvalue.\nThis implies that the axial U(1) symmetry is partially restored, so that the\nlow energy symmetry of the theory becomes SU(2)$\\otimes$ SU(2)$\\otimes$ Z$_4$.\nSecondly, we report recent numerical investigations on this issue by lattice\nQCD simulations with lattice chiral fermions such as Overlap or improved\ndomain-wall fermions. Our preliminary results indicate that the eigenvalue\ndensity seems to have a gap at the origin just above $T_c$, the temperature of\nthe chiral symmetry restoration, which implies the axial U(1) symmetry is\neffectively restored at high temperature. We also point out an importance of\nthe exact lattice chiral symmetry to obtain correct results on this issue.",
        "positive": "Radiative Transitions in Charmonium: The form factors for the radiative transitions between charmonium mesons are\ninvestigated. We employ an anisotropic lattice using a Wilson gauge action, and\ndomain-wall fermion action. We extrapolate the form factors to $Q^2 = 0$,\ncorresponding to a real photon, using quark-model-inspired functions. Finally,\ncomparison is made with photocouplings extracted from the measured radiative\nwidths, where known. Our preliminary results find photocouplings commensurate\nwith these experimentally extracted values."
    },
    {
        "anchor": "Higher partial wave contamination in finite-volume 1-to-2 transitions: In their seminal work, Lellouch and L\\\"uscher derived a conversion factor\nrelating a finite-volume matrix element, calculable using numerical lattice\nQCD, with the infinite-volume decay amplitude for $K \\to \\pi \\pi$. The\nconversion factor depends on the $\\pi \\pi \\to \\pi \\pi$ scattering amplitude\nwith the same total isospin (either zero or two) as the $\\pi \\pi$ decay\nchannel. Although an infinite tower of $\\pi \\pi \\to \\pi \\pi$ partial-wave\ncomponents affect the conversion factor, the $S$-wave ($\\ell=0$) component is\nexpected to dominate, and only this contribution is included in the well-known\nLellouch-L\\\"uscher factor, with other $\\pi \\pi \\to \\pi \\pi$ partial-wave\namplitudes formally set to zero. However, as the precision of lattice\ncalculations increases, it may become important to assess the systematic\nuncertainty arising from this approximation. With this motivation, we compare\nthe $S$-wave-only results with those truncated at the next contaminating\npartial wave: the $G$-wave ($\\ell=4$) for zero total momentum in the\nfinite-volume frame and the $D$-wave ($\\ell=2$) otherwise. Using the general\nframework for $1 \\overset{\\mathcal J}{\\to} 2$ transitions, we quantify the\neffect of higher partial waves for systems with zero and non-zero total\nmomentum as well as with anti-periodic boundary conditions, presenting both\ngeneric numerical examples and results for realistic $\\pi \\pi$ amplitudes taken\nfrom chiral perturbation theory and dispersive analysis. We also consider the\naccidental degeneracy occurring in the 8$^{\\text {th}}$ excited state of the\nzero-momentum system. This exhibits qualitatively new features at $\\ell=4$, not\nseen in the $\\ell=0$ truncation.",
        "positive": "Lattice computation of the quark propagator in Landau gauge at finite\n  temperature: We report on the lattice computation of the quark propagator at finite\ntemperature in the Landau gauge, using quenched gauge configurations. The\npropagator form factors are computed for various temperatures, above and below\nthe gluon deconfinement temperature $T_c$, and for all the Matsubara\nfrequencies. Our results suggest a strong connection between quark and gluon\ndeconfinement and chiral symmetry restoration above $T_c$."
    },
    {
        "anchor": "NPR step-scaling across the charm threshold: Matching Non-Perturbative Renormalisation on the lattice and perturbative\nrenormalisation would benefit from higher matching scales, which are needed for\nobservables entering their permile era such as BK. In this work we lay down a\nstrategy, within the Rome-Southampton framework, to push this scale higher\nacross the charm threshold, and apply it to an exploration of the BK running\nfrom 3 GeV to 9 GeV. This is done on Nf = 2+1+1 ensembles generated by the\nRBC-UKQCD collaboration, and features a close study of the discretisation\neffects.",
        "positive": "The Reality of the Fundamental Topological Structure in the QCD Vacuum: Long-range order of a specific kind has recently been found directly in\nconfigurations dominating the regularized QCD path integral. In particular, a\nlow-dimensional global structure was identified in typical space-time\ndistributions of topological charge defined via the overlap Dirac matrix. The\npresence of the order has been concluded from the fact that the structure\ndisappears after random permutation of position coordinates in measured\ndensities. Here we complete the argument for the reality of this structure\n(namely the conjecture that its existence is a consequence of QCD dynamics and\nnot an artifact of the overlap-based definition of lattice topological field)\nby showing that the structure ceases to exist after randomizing the space-time\ncoordinates of the underlying gauge field. This implies that the long-range\norder present in the overlap-based topological density is indeed a\nmanifestation of QCD vacuum, and that the notion of the fundamental structure\n(structure involving relevant features at all scales) is viable."
    },
    {
        "anchor": "High-accuracy two-loop computation of the critical mass for Wilson\n  fermions: We test an algebraic algorithm based on the coordinate-space method,\nevaluating with high accuracy the critical mass for Wilson fermions in lattice\nQCD at two loops. We test the results by using different types of infrared\nregularization.",
        "positive": "Recent results from systematic parameterizations of Ginsparg-Wilson\n  fermions: The Fixed Point Dirac Operator and Chirally Improved Fermions both use large\nnumbers of gauge paths and the full Dirac structure to approximate a solution\nof the Ginsparg-Wilson equation. After a brief review of the two approaches we\npresent recent results for quenched QCD with pion masses down to 210 MeV. We\ndiscuss the limits and advantages of approximate parameterizations and outline\nfuture perspectives."
    },
    {
        "anchor": "Metastable nonconfining states in SU(3) lattice gauge theory with sextet\n  fermions: We study the SU(3) lattice gauge theory, with two flavors of sextet\nWilson-clover fermions, near its finite-temperature phase transition. We find\nmetastable states that have Wilson line expectation values whose complex phases\nare near 2pi/3 or pi. The true equilibrium phase at these couplings and\ntemperatures has its Wilson line oriented only towards the positive real axis,\nin agreement with perturbation theory.",
        "positive": "Multigrid for Chiral Lattice Fermions: Domain Wall: Critical slowing down for the Krylov Dirac solver presents a major obstacle\nto further advances in lattice field theory as it approaches the continuum\nsolution. We propose a new multi-grid approach for chiral fermions, applicable\nto both the 5-d domain wall or 4-d Overlap operator. The central idea is to\ndirectly coarsen the 4-d Wilson kernel, giving an effective domain wall or\noverlap operator on each level. We provide here an explicit construction for\nthe Shamir domain wall formulation with numerical tests for the 2-d Schwinger\nprototype, demonstrating near ideal multi-grid scaling. The framework is\ndesigned for a natural extension to 4-d lattice QCD chiral fermions, such as\nthe M\\\"obius, Zolotarev or Borici domain wall discretizations or directly to a\nrational expansion of the 4-d Overlap operator. For the Shamir operator, the\neffective overlap operator is isolated by the use of a Pauli-Villars\npreconditioner in the spirit of the K\\\"ahler-Dirac spectral map used in a\nrecent staggered MG algorithm [1]."
    },
    {
        "anchor": "The M\u00f6bius Domain Wall Fermion Algorithm: We present a review of the properties of generalized domain wall Fermions,\nbased on a (real) M\\\"obius transformation on the Wilson overlap kernel,\ndiscussing their algorithmic efficiency, the degree of explicit chiral\nviolations measured by the residual mass ($m_{res}$) and the Ward-Takahashi\nidentities. The M\\\"obius class interpolates between Shamir's domain wall\noperator and Bori\\c{c}i's domain wall implementation of Neuberger's overlap\noperator without increasing the number of Dirac applications per conjugate\ngradient iteration. A new scaling parameter ($\\alpha$) reduces chiral\nviolations at finite fifth dimension ($L_s$) but yields exactly the same\noverlap action in the limit $L_s \\rightarrow \\infty$. Through the use of 4d\nRed/Black preconditioning and optimal tuning for the scaling $\\alpha(L_s)$, we\nshow that chiral symmetry violations are typically reduced by an order of\nmagnitude at fixed $L_s$. At large $L_s$ we argue that the observed scaling for\n$m_{res} = O(1/L_s)$ for Shamir is replaced by $m_{res} = O(1/L_s^2)$ for the\nproperly tuned M\\\"obius algorithm with $\\alpha = O(L_s)$",
        "positive": "Lattice simulation of a center symmetric three-dimensional effective\n  theory for SU(2) Yang-Mills: We perform simulations of an effective theory of SU(2) Wilson lines in three\ndimensions. Our action includes a kinetic term, the one-loop perturbative\npotential for the Wilson line, a non-perturbative \"fuzzy-bag\" contribution and\nspatial gauge fields. We determine the phase diagram of the theory and confirm\nthat, at moderately weak coupling, the non-perturbative term leads to\neigenvalue repulsion in a finite region above the deconfining phase transition."
    },
    {
        "anchor": "Impossibility of spontaneous vector flavor symmetry breaking on the\n  lattice: I show that spontaneous breaking of vector flavor symmetry on the lattice is\nimpossible in gauge theories with a positive functional-integral measure, for\ndiscretized Dirac operators linear in the quark masses, if the corresponding\npropagator and its commutator with the flavor symmetry generators can be\nbounded in norm independently of the gauge configuration and uniformly in the\nvolume. Under these assumptions, any order parameter vanishes in the symmetric\nlimit of fermions of equal masses. I show that these assumptions are satisfied\nby staggered, minimally doubled and Ginsparg-Wilson fermions for positive\nfermion mass, for any value of the lattice spacing, and so in the continuum\nlimit if this exists. They are instead not satisfied by Wilson fermions, for\nwhich spontaneous vector flavor symmetry breaking is known to take place in the\nAoki phase. The existence of regularizations unaffected by residual fermion\ndoubling for which the symmetry cannot break spontaneously on the lattice\nestablishes rigorously (at the physicist's level) the impossibility of its\nspontaneous breaking in the continuum for any number of flavors.",
        "positive": "The critical end point of QCD: We investigate the critical end point of QCD with two flavours of light\ndynamical quarks at finite lattice cutoff a=1/4T using a Taylor expansion of\nthe baryon number susceptibility. We find a strong volume dependence of the\nposition of the critical end point. In the large volume limit we obtain T^E/T_c\n\\~ 0.95 and mu_B^E/T^E ~ 1.1, where T_c is the cross over temperature at zero\nchemical potential, and T^E and mu_B^E are the temperature and the baryon\nchemical potential at the critical end point. The small value of mu_B^E places\nit in the range of observability in energy scans at the RHIC."
    },
    {
        "anchor": "Finite-volume correction on the hadronic vacuum polarization\n  contribution to muon g-2 in lattice QCD: We study the finite-volume correction on the hadronic vacuum polarization\ncontribution to the muon g-2 ($a_\\mu^{\\rm hvp}$) in lattice QCD at (near)\nphysical pion mass using two different volumes: $(5.4~{\\rm fm})^4$ and\n$(8.1~{\\rm fm})^4$. We use an optimized AMA technique for noise reduction on\n$N_f=2+1$ PACS gauge configurations with stout-smeared clover-Wilson fermion\naction and Iwasaki gauge action at a single lattice cut-off $a^{-1}=2.33$ GeV.\nThe calculation is performed for the quark-connected light-quark contribution\nin the isospin symmetric limit. We take into account the effects of backward\nstate propagation by extending a temporal boundary condition. In addition we\nstudy a quark-mass correction to tune to the exactly same physical pion mass on\ndifferent volume and compare those correction with chiral perturbation. We find\n$10(26)\\times10^{-10}$ difference for light quark $a_\\mu^{\\rm hvp}$ between\n$(5.4~{\\rm fm})^4$ and $(8.1~{\\rm fm})^4$ lattice in 146 MeV pion.",
        "positive": "Pion mass dependence of the HVP contribution to muon $g-2$: One of the systematic errors in some of the current lattice computations of\nthe HVP contribution to the muon anomalous magnetic moment $g-2$ is that\nassociated with the extrapolation to the physical pion mass. We investigate\nthis extrapolation assuming lattice pion masses in the range of 220 to 440 MeV\nwith the help of two-loop chiral perturbation theory, and find that such an\nextrapolation is unlikely to lead to control of this systematic error at the 1%\nlevel. This remains true even if various proposed tricks to improve the chiral\nextrapolation are taken into account."
    },
    {
        "anchor": "Determination of the Static Potential with Dynamical Fermions: We present in detail a technique to extract the potential between a static\nquark and anti-quark pair from Wilson loops measured on dynamical\nconfigurations. This technique is based on HYP smearing and leads to an\nexponential improvement of the noise-to-signal ratio of Wilson loops. We\nexplain why the correct continuum potential is obtained and show numerical\nevidence that the cut-off effects are small. We present precise results for the\nnon-perturbative potential. As applications, we determine the scale r_0/a and\nstudy the shape of the static potential in the range of distances around r_0,\nwhere it can be compared with phenomenological potential models.",
        "positive": "B-physics computations from Nf=2 tmQCD: We present an accurate lattice QCD computation of the b-quark mass, the B and\nBs decay constants, the B-mixing bag-parameters for the full four-fermion\noperator basis, as well as estimates for \\xi and f_{Bq}\\sqrt{B_q} extrapolated\nto the continuum limit and the physical pion mass. We have used Nf = 2\ndynamical quark gauge configurations at four values of the lattice spacing\ngenerated by ETMC. Extrapolation in the heavy quark mass from the charm to the\nbottom quark region has been carried out using ratios of physical quantities\ncomputed at nearby quark masses, having an exactly known infinite mass limit."
    },
    {
        "anchor": "A non-perturbative study of massive gauge theories: We consider a non-perturbative formulation of an SU(2) massive gauge theory\non a space-time lattice, which is also a discretised gauged non-linear chiral\nmodel. The lattice model is shown to have an exactly conserved global SU(2)\nsymmetry. If a scaling region for the lattice model exists and the lightest\ndegrees of freedom are spin one vector particles with the same quantum numbers\nas the conserved current, we argue that the most general effective theory\ndescribing their low-energy dynamics must be a massive gauge theory. We present\nresults of a exploratory numerical simulation of the model and find indications\nfor the presence of a scaling region where both a triplet vector and a scalar\nremain light.",
        "positive": "The kaon semileptonic form factor in Nf=2+1 domain wall lattice QCD with\n  physical light quark masses: We present the first calculation of the kaon semileptonic form factor with\nsea and valence quark masses tuned to their physical values in the continuum\nlimit of 2+1 flavour domain wall lattice QCD. We analyse a comprehensive set of\nsimulations at the phenomenologically convenient point of zero momentum\ntransfer in large physical volumes and for two different values of the lattice\nspacing. Our prediction for the form factor is f+(0)=0.9685(34)(14) where the\nfirst error is statistical and the second error systematic. This result can be\ncombined with experimental measurements of K->pi decays for a determination of\nthe CKM-matrix element for which we predict |Vus|=0.2233(5)(9) where the first\nerror is from experiment and the second error from the lattice computation."
    },
    {
        "anchor": "The leading hadronic vacuum polarisation on the lattice: After discussing the relevance of a first principles theory-prediction of the\nhadronic vacuum polarisation for Standard Model tests, the theoretical\nchallenges for its computation in lattice QCD are reviewed. New ideas that will\npotentially improve the quality of lattice simulations will be introduced and\nthe status of ongoing simulations will be presented briefly.",
        "positive": "Interglueball potential in SU(N) lattice gauge theory: We report on our calculation of the interglueball potentials in SU(2), SU(3),\nand SU(4) lattice Yang-Mills theories using the indirect (so-called HAL QCD)\nmethod. We use the cluster decomposition error reduction technique to improve\nthe statistical accuracy of the glueball correlators. After calculating the\nglueball scattering cross section in SU(2) Yang-Mills theory and combining with\nthe observational data of the dark matter mass distributions, we derive the\nlower limit on the scale parameter."
    },
    {
        "anchor": "Chiral phase transition at finite temperature and conformal dynamics in\n  large Nf QCD: We investigate the chiral phase transition at finite temperature (T) in\ncolour SU(Nc=3) Quantum Chromodynamics (QCD) with six species of fermions\n(Nf=6) in the fundamental representation by using lattice QCD with improved\nstaggered fermions. By considering lattices with several temporal extensions\nNt, we observe asymptotic scaling for Nt > 4. We then extract the dimensionless\nratio Tc/Lambda_L (Lambda_L = Lattice Lambda-parameter) for Nf = 6 and Nf = 8,\nthe latter relying on our earlier results. Further, we collect the critical\ncouplings beta^c for the chiral phase transition at Nf = 0 (quenched), and Nf =\n4 at a fixed Nt = 6. The results are consistent with enhanced fermionic\nscreening at larger Nf. The Tc/Lambda_L depends very mildly on Nf in the Nf = 0\n- 4 region, starts increasing at Nf = 6, and becomes significantly larger at Nf\n= 8, close to the edge of the conformal window. We discuss interpretations of\nthese results as well as their possible interrelation with preconformal\ndynamics in the light of a functional renormalization group analysis.",
        "positive": "Renormalization of Currents for Massive Fermions: The renormalization of vector and axial-vector currents for massive fermions\n(in the ``Fermilab formalism'') is discussed. We give results for\nnon-degenerate masses, which are needed for semi-leptonic form factors."
    },
    {
        "anchor": "Three-point vertices in Landau-gauge Yang-Mills theory: Vertices are of central importance for constructing QCD bound states out of\nthe individual constituents of the theory, i.e. quarks and gluons. In\nparticular, the determination of three-point vertices is crucial in\nnon-perturbative investigations of QCD. We use numerical simulations of lattice\ngauge theory to obtain results for the 3-point vertices in Landau-gauge SU(2)\nYang-Mills theory in three and four space-time dimensions for various kinematic\nconfigurations. In all cases considered, the ghost-gluon vertex is found to be\nessentially tree-level-like, while the three-gluon vertex is suppressed at\nintermediate momenta. For the smallest physical momenta, reachable only in\nthree dimensions, we find that some of the three-gluon-vertex tensor structures\nchange sign.",
        "positive": "Coulomb gauge on the lattice: From zero to finite temperature: Our previous studies of Coulomb gauge Yang-Mills theory are extended to\nfinite temperature. We investigate the SU(2) static gluon and ghost propagators\nand show results for the Coulomb potential, with a focus on the Gribov\nambiguity. To compute these quantities at high temperatures and to solve\nscaling violations we use the anisotropic Wilson gauge action."
    },
    {
        "anchor": "The Low Energy Constants of $SU(2)$ Partially Quenched Chiral\n  Perturbation Theory from $N_{f}=2+1$ Domain Wall QCD: We have performed fits of the pseudoscalar masses and decay constants, from a\nvariety of RBC-UKQCD domain wall fermion ensembles, to $SU(2)$ partially\nquenched chiral perturbation theory at next-to leading order (NLO) and\nnext-to-next-to leading order (NNLO). We report values for 9 NLO and 8 linearly\nindependent combinations of NNLO partially quenched low energy constants, which\nwe compare to other lattice and phenomenological determinations. We discuss the\nsize of successive terms in the chiral expansion and use our large set of low\nenergy constants to make predictions for mass splittings due to QCD isospin\nbreaking effects and the S-wave $\\pi \\pi$ scattering lengths. We conclude that,\nfor the range of pseudoscalar masses explored in this work, $115~\\mathrm{MeV}\n\\lesssim m_{\\rm PS} \\lesssim 430~\\mathrm{MeV}$, the NNLO $SU(2)$ expansion is\nquite robust and can fit lattice data with percent-scale accuracy.",
        "positive": "Lattice supersymmetric Ward identities: SUSY Ward identities for the N=1 SU(2) SUSY Yang-Mills theory are studied on\nthe lattice in a non-perturbative numerical approach. As a result a\ndetermination of the subtracted gluino mass is obtained."
    },
    {
        "anchor": "Calculation of $c_\\mathrm{SW}$ at one-loop order for Brillouin fermions: The Brillouin action is a Wilson-like lattice fermion action with a 81-point\nstencil, which was found to ameliorate the Wilson action in many respects. The\nSheikholeslami-Wohlert coefficient $c_\\mathrm{SW}$ of the clover improvement\nterm has a perturbative expansion\n$c_\\mathrm{SW}=c_\\mathrm{SW}^{(0)}+g_0^2c_\\mathrm{SW}^{(1)}+\\mathcal{O}(g_0^4)$.\nAt tree-level $c_\\mathrm{SW}^{(0)}=r$ holds for Wilson and Brillouin fermions\nalike. We present the Feynman rules for the Brillouin action in lattice\nperturbation theory, and employ them to calculate the one-loop coefficient\n$c_\\mathrm{SW}^{(1)}$ with plaquette or L\\\"uscher-Weisz gluons. Numerically its\nvalue is found to be about half that of the Wilson action.",
        "positive": "Finite temperature properties of QCD with two flavors and three, four\n  and five colors: I present a numerical study of the crossover between the low temperature\nchirally broken phase and the high temperature chirally restored phase in\n$SU(N_c)$ gauge theory with $N_c=3-5$ colors and $N_f=2$ degenerate fermion\nflavors. Fermion masses span a range of intermediate values (represented by the\nsquared ratio of pseudoscalar to vector meson masses $(m_{PS}/m_V)^2\\sim 0.25$\nto 0.63). Observables include the temperature dependent chiral condensate and\nscreening masses. At each fermion mass these quantities show nearly identical\ntemperature dependence across $N_c$."
    },
    {
        "anchor": "A New Strategy for the Lattice Evaluation of the Leading Order Hadronic\n  Contribution to $(g-2)_\u03bc$: A reliable evaluation of the integral giving the hadronic vacuum polarization\ncontribution to the muon anomalous magnetic moment should be possible using a\nsimple trapezoid-rule integration of lattice data for the subtracted\nelectromagnetic current polarization function in the Euclidean momentum\ninterval $Q^2>Q^2_{min}$, coupled with an $N$-parameter Pad\\'e or other\nrepresentation of the polarization in the interval $0<Q^2<Q^2_{min}$, for\nsufficiently high $Q^2_{min}$ and sufficiently large $N$. Using a physically\nmotivated model for the $I=1$ polarization, and the covariance matrix from a\nrecent lattice simulation to generate associated fake \"lattice data,\" we show\nthat systematic errors associated with the choices of $Q^2_{min}$ and $N$ can\nbe reduced to well below the 1% level for $Q^2_{min}$ as low as 0.1 GeV$^2$ and\nrather small $N$. For such low $Q^2_{min}$, both an NNLO chiral representation\nwith one additional NNNLO term and a low-order polynomial expansion employing a\nconformally transformed variable also provide representations sufficiently\naccurate to reach this precision for the low-$Q^2$ contribution. Combined with\nstandard techniques for reducing other sources of error on the lattice\ndetermination, this hybrid strategy thus looks to provide a promising approach\nto reaching the goal of a sub-percent precision determination of the hadronic\nvacuum polarization contribution to the muon anomalous magnetic moment on the\nlattice.",
        "positive": "The mass spectrum of the Schwinger model with Matrix Product States: We show the feasibility of tensor network solutions for lattice gauge\ntheories in Hamiltonian formulation by applying matrix product states\nalgorithms to the Schwinger model with zero and non-vanishing fermion mass. We\nintroduce new techniques to compute excitations in a system with open boundary\nconditions, and to identify the states corresponding to low momentum and\ndifferent quantum numbers in the continuum. For the ground state and both the\nvector and scalar mass gaps in the massive case, the MPS technique attains\nprecisions comparable to the best results available from other techniques."
    },
    {
        "anchor": "Two-dimensional ${\\cal N} = (2, 2)$ Lattice Gauge Theories with Matter\n  in Higher Representations: We construct two-dimensional ${\\cal N} = (2, 2)$ supersymmetric gauge\ntheories on a Euclidean spacetime lattice with matter in the two-index\nsymmetric and anti-symmetric representations of SU($N_c$) color group. These\nlattice theories preserve a subset of the supercharges exact at finite lattice\nspacing. The method of topological twisting is used to construct such theories\nin the continuum and then the geometric discretization scheme is used to\nformulate them on the lattice. The lattice theories obtained this way are\ngauge-invariant, free from fermion doubling problem and exact supersymmetric at\nfinite lattice spacing. We hope that these lattice constructions further\nmotivate the nonperturbative explorations of models inspired by technicolor,\norbifolding and orientifolding in string theories and the Corrigan-Ramond\nlimit.",
        "positive": "More on strongly coupled quenched QED: We study the critical region of lattice QED4 in the quenched approximation.\nThe issue of triviality is addressed by contrasting simulation results for\n$<\\bar\\psi\\psi>$ and for the susceptibilities with the predictions of two\ncritical scenarios -- powerlaw scaling, and triviality \\`a la Nambu--Jona\nLasinio. We discriminate among the two possibilities with reasonable accuracy\nand we confirm previous results for the critical point and exponents thanks to\nnew analysis strategies and good quality data. The interplay of chiral symmetry\nbreaking with the Goldstone mechanism is studied in detail, and some puzzling\nfeatures of past results are clarified. Chiral symmetry restoration is observed\nin the spectrum: the candidate Goldstone boson decouples in the weak coupling\nphase, while the propagators of the chiral doublets become degenerate. We also\npresent the first measurements of the full mesonic spectrum, relevant for the\nstudy of flavour/ rotational symmetry restoration. The systematic effects\nassociated"
    },
    {
        "anchor": "Counting-Based Effective Dimension and Discrete Regularizations: Fractal-like structures of varying complexity are common in nature, and\nmeasure-based dimensions (Minkowski, Hausdorff) supply their basic geometric\ncharacterization. However, at the level of fundamental dynamics, which is\nquantum, structure does not enter via geometry of fixed sets but is encoded in\nprobability distributions on associated spaces. The question then arises\nwhether a robust notion of fractal measure-based dimension exists for\nstructures represented in this way. Starting from effective number theory, we\nconstruct all counting-based schemes to select effective supports on\ncollections of objects with probabilities and associate the effective counting\ndimension (ECD) with each. We then show that ECD is scheme-independent and,\nthus, a well-defined measure-based dimension with meaning analogous to the\nMinkowski dimension of fixed sets. In physics language, ECD characterizes\nprobabilistic descriptions arising in a theory or model via discrete\n``regularization''. For example, our analysis makes recent surprising results\non effective spatial dimensions in quantum chromodynamics and Anderson models\nwell founded. We discuss how to assess the reliability of regularization\nremovals in practice and perform such analysis in the context of 3d Anderson\ncriticality.",
        "positive": "Lattice construction of mixed 't Hooft anomaly with higher-form symmetry: In this talk, we give the lattice regularized formulation of the mixed 't\nHooft anomaly between the $\\mathbb{Z}_N$ $1$-form symmetry and the $\\theta$\nperiodicity for $4$d pure Yang-Mills theory, which was originally discussed by\nGaiotto $\\textit{et al.}$ in the continuum description. For this purpose, we\ndefine the topological charge of the lattice $SU(N)$ gauge theory coupled with\nthe background $\\mathbb{Z}_N$ $2$-form gauge fields $B_p$ by generalizing\nL\\\"uscher's construction of the $SU(N)$ topological charge. We show that this\nlattice topological charge enjoys the fractional $1/N$ shift completely\ncharacterized by the background gauge field $B_p$, and this rigorously proves\nthe mixed 't Hooft anomaly with the finite lattice spacings. As a consequence,\nthe Yang-Mills vacua at $\\theta$ and $\\theta+2\\pi$ are distinct as the\nsymmetry-protected topological states when the confinement is assumed."
    },
    {
        "anchor": "Lee-Yang zero distribution of high temperature QCD and Roberge-Weiss\n  phase transition: Canonical partition functions and Lee-Yang zeros of QCD at finite density and\nhigh temperature are studied. Recent lattice simulations have confirmed that\nthe free energy of QCD is a quartic function of quark chemical potential at\ntemperature slightly above pseudo-critical temperature $T_c$, as in the case\nwith a gas of free massless fermions.\n  We present analytic derivation of the canonical partition functions and\nLee-Yang zeros for this type of free energy using the saddle point\napproximation. We also perform lattice QCD simulation in a canonical approach\nusing the fugacity expansion of the fermion determinant, and carefully examine\nits reliability. By comparing the analytic and numerical results, we conclude\nthat the canonical partition functions follow the Gaussian distribution of the\nbaryon number, and the accumulation of Lee-Yang zeros of these canonical\npartition functions exhibit the first-order Roberge-Weiss phase transition. We\ndiscuss the validity and applicable range of the result and its implications\nboth for theoretical and experimental studies.",
        "positive": "Nucleon charges and form factors using clover and HISQ ensembles: We present high statistics ($\\mathcal{O}(2\\times 10^5)$ measurements)\npreliminary results on (i) the isovector charges, $g^{u-d}_{A,S,T}$, and form\nfactors, $G^{u-d}_E(Q^2)$, $G^{u-d}_M(Q^2)$, $G^{u-d}_A(Q^2)$, $\\widetilde\nG^{u-d}_P(Q^2)$, $G^{u-d}_P(Q^2)$, on six 2+1-flavor Wilson-clover ensembles\ngenerated by the JLab/W&M/LANL/MIT collaboration with lattice parameters given\nin Table 1. Examples of the impact of using different estimates of the excited\nstate spectra are given for the clover-on-clover data, and as discussed in [1],\nthe biggest difference on including the lower energy (close to $N\\pi$ and\n$N\\pi\\pi$) states is in the axial channel. (ii) Flavor diagonal axial, tensor\nand scalar charges, $g^{u,d,s}_{A,S,T}$, are calculated with the clover-on-HISQ\nformulation using nine 2+1+1-flavor HISQ ensembles generated by the MILC\ncollaboration [2] with lattice parameters given in Table 2. Once finished, the\ncalculations of $g^{u,d,s}_{A,T}$ will update the results given in Refs.[3,4].\nThe estimates for $g^{u,d,s}_{S}$ and $\\sigma_{N\\pi}$ are new. Overall, a large\npart of the focus is on understanding the excited state contamination (ESC),\nand the results discussed provide a partial status report on developing\ndefensible analyses strategies that include contributions of possible low-lying\nexcited states to individual nucleon matrix elements."
    },
    {
        "anchor": "wickop: Lattice Cubic Rotation Operator Generator: This document outlines the usage of a series of python 2.7 scripts designed\nto easily and efficiently create compound operators. This is accomplished by\ncomputing tensor products of smaller building blocks that transform irreducibly\nunder lattice cubic rotational and translational symmetry. In particular, the\ncode has the ability to handle representations of the cubic rotation group with\nany spatial momentum. The key paradigm is to track the momentum separately from\nthe rotations, fully utilizing the abelian structure of the translation\nsubgroup. This goes through the Wigner little group method to classify the\nsubgroup of rotations that leave the momentum direction unchanged. Using little\ngroups circumvents the issue of a volume factor in the number of representation\nmatrices that are needed, instead only requiring the 96 cubic rotation\nrepresentation matrices. Tensor products are computed with character tables and\nClebsch-Gordan coefficients are saved for each decomposition in the tensor\nproduct. The code also builds operators in a consistent basis, ensuring that\noperators that transform in the same representation have the same properties.",
        "positive": "Asymptotic Scaling in the Two-Dimensional $O(3)$ $\u03c3$-Model at\n  Correlation Length $10^5$: We carry out a high-precision Monte Carlo simulation of the two-dimensional\n$O(3)$-invariant $\\sigma$-model at correlation lengths $\\xi$ up to $\\sim 10^5$.\nOur work employs a new and powerful method for extrapolating finite-volume\nMonte Carlo data to infinite volume, based on finite-size-scaling theory. We\ndiscuss carefully the systematic and statistical errors in this extrapolation.\nWe then compare the extrapolated data to the renormalization-group predictions.\nThe deviation from asymptotic scaling, which is $\\approx 25\\%$ at $\\xi \\sim\n10^2$, decreases to $\\approx 4\\%$ at $\\xi \\sim 10^5$."
    },
    {
        "anchor": "Aspects of Confinement in Coulomb Gauge: I present some new results regarding confinement as it appears in Coulomb\ngauge. It is found that: i) a recently proposed Yang-Mills vacuum\nwavefunctional in temporal gauge and 2+1 dimensions yields a Coulomb-gauge\nghost propagator and linear Coulomb potential in good agreement with lattice\nMonte Carlo results; ii) adding a few constituent gluons to heavy\nquark-antiquark states brings the interaction energy much closer to that of the\nstatic quark potential, and suggests the beginnings of gluon-chain formation at\nroughly one fermi; iii) a perturbative approach to Faddeev-Popov eigenvalues\nindicates that the zero eigenvalue at the Gribov horizon may occur either at,\nor away from, p=0, depending on the gauge choice and spacetime dimension. This\nlast result may be relevant to the qualitatively different infrared behavior of\nthe ghost propagator in Coulomb and Landau gauges.",
        "positive": "Three-Dimensional Simplicial Gravity and Degenerate Triangulations: I define a model of three-dimensional simplicial gravity using an extended\nensemble of triangulations where, in addition to the usual combinatorial\ntriangulations, I allow degenerate triangulations, i.e. triangulations with\ndistinct simplexes defined by the same set of vertexes. I demonstrate, using\nnumerical simulations, that allowing this type of degeneracy substantially\nreduces the geometric finite-size effects, especially in the crumpled phase of\nthe model, in other respect the phase structure of the model is not affected."
    },
    {
        "anchor": "Improving Multigrid and Conventional Relaxation Algorithms for\n  Propagators: Practical modifications of deterministic multigrid and conventional\nrelaxation algorithms are discussed. New parameters need not be tuned but are\ndetermined by the algorithms themselves. One modification can be thought of as\n``updating on a last layer consisting of a single site''. It eliminates\ncritical slowing down in computations of bosonic and fermionic propagators in a\nfixed volume. Here critical slowing down means divergence of asymptotic\nrelaxation times as the propagators approach criticality. A remaining volume\ndependence is weak enough in case of bosons so that conjugate gradient can be\noutperformed. However, no answer can be given yet if the same is true for\nstaggered fermions on lattices of realizable sizes. Numerical results are\npresented for propagators of bosons and of staggered fermions in 4-dimensional\n$SU(2)$ gauge fields.",
        "positive": "Perturbative calculations for the HISQ action: the gluon action at\n  $O(N_f\u03b1_sa^2)$: We present a new (and general) algorithm for deriving lattice Feynman rules\nwhich is capable of handling actions as complex as the Highly Improved\nStaggered Quark (HISQ) action. This enables us to perform a perturbative\ncalculation of the influence of dynamical HISQ fermions on the perturbative\nimprovement of the gluonic action in the same way as we have previously done\nfor asqtad fermions. We find the fermionic contributions to the radiative\ncorrections in the L\\\"uscher-Weisz gauge action to be somewhat larger for HISQ\nfermions than for asqtad."
    },
    {
        "anchor": "Fermions in the pseudoparticle approach: The pseudoparticle approach is a numerical technique to compute path\nintegrals without discretizing spacetime. The basic idea is to integrate over\nthose field configurations, which can be represented by a sum of a fixed number\nof localized building blocks (pseudoparticles). In a couple of previous papers\nwe have successfully applied the pseudoparticle approach to pure SU(2)\nYang-Mills theory. In this work we discuss how to incorporate fermionic fields\nin the pseudoparticle approach. To test our method, we compute the phase\ndiagram of the 1+1-dimensional Gross-Neveu model in the large-N limit.",
        "positive": "Number-theory renormalization of vacuum energy: For QFT on a lattice of dimension d>=3, the vacuum energy (both bosonic and\nfermionic) is zero if the Hamiltonian is a function of the square of the\nmomentum, and the calculation of the vacuum energy is performed in the ring of\nresidue classes modulo N. This fact is related to a problem from number theory\nabout the number of ways to represent a number as a sum of $d$ squares in the\nring of residue classes modulo N."
    },
    {
        "anchor": "Positivity violation for the lattice Landau gluon propagator: We present explicit numerical evidence of reflection-positivity violation for\nthe lattice Landau gluon propagator in three-dimensional pure SU(2) gauge\ntheory. We use data obtained at very large lattice volumes (V = 80^3, 140^3)\nand for three different lattice couplings in the scaling region (beta = 4.2,\n5.0, 6.0). In particular, we observe a clear oscillatory pattern in the\nreal-space propagator C(t). We also verify that the (real-space) data show good\nscaling in the range t \\in [0,3] fm and can be fitted using a Gribov-like form.\nThe violation of positivity is in contradiction with a stable-particle\ninterpretation of the associated field theory and may be viewed as a\nmanifestation of confinement.",
        "positive": "Coherent center domains in SU(3) gluodynamics and their percolation at\n  T_c: For SU(3) lattice gauge theory we study properties of static quark sources\nrepresented by local Polyakov loops. We find that for temperatures both below\nand above T_c coherent domains exist where the phases of the local loops have\nsimilar values in the vicinity of the center values 0, +/- 2 pi/3. The cluster\nproperties of these domains are studied numerically. We demonstrate that the\ndeconfinement transition of SU(3) may be characterized by the percolation of\nsuitably defined clusters."
    },
    {
        "anchor": "Finite-temperature phase transition of $N_{f}=3$ QCD with exact center\n  symmetry: For the $Z_{3}$-symmetric lattice QCD-like theory ($Z_3$-QCD), in which\n$SU(3)$ gauge theory is coupled with three fundamental Wilson quarks with\nflavor-dependent twisted boundary conditions, we calculate the expectation\nvalues of Polyakov loop and chiral condensate as functions of temperature on\n$16^3 \\times4$ and $20^3 \\times 4$ lattices with $m_{PS}/m_{V}=0.70$ fixed. We\nfind the first-order phase transition with respect to the $Z_{3}$ center\nsymmetry, where the Polyakov loop exhibits a hysteresis depending on the\ninitial condition of thermalization process. We also show that the crossover\nbehavior of chiral condensate around the critical temperature of the center\ntransition and the manifestation of flavor symmetry breaking in the\nhigh-temperature phase.",
        "positive": "Chiral symmetry breaking at large N_c: We present numerical evidence for the hypothesis that, in the planar limit,\nfour dimensional Euclidean Yang-Mills theory on a finite symmetrical four-torus\nbreaks chiral symmetry spontaneously when the length of the sides l is larger\nthan a critical value l_c with a bilinear condensate whose value is independent\nof l. Therefore spontaneous symmetry breaking occurs at finite volume and\ninfinite N_c reduction holds for the chiral condensate."
    },
    {
        "anchor": "Impact of dynamical charm quarks: We compute and compare the continuum limits of several quantities in QCD with\nand without a dynamical charm quark. We consider both low energy quantities,\nlike the hadronic scales $r_0$ and $t_0$, and high energy quantities, like the\ncharmonium masses.",
        "positive": "3d Lorentzian, Dynamically Triangulated Quantum Gravity: The model of Lorentzian three-dimensional dynamical triangulations provides a\nnon-perturbative definition of three-dimensional quantum gravity. The theory\nhas two phases: a weak-coupling phase with quantum fluctuations around a\n``semiclassical'' background geometry which is generated dynamically despite\nthe fact that the formulation is explicitly background-independent, and a\nstrong-coupling phase where ``classical'' space disintegrates into a foam of\nbaby universes."
    },
    {
        "anchor": "Disconnected hadronic vacuum polarization contribution to the muon g-2\n  with HISQ: We describe a computation of the contribution to the anomalous magnetic\nmoment of the muon from the disconnected part of the hadronic vacuum\npolarization. We use the highly-improved staggered quark (HISQ) formulation for\nthe current density with gauge configurations generated with four flavors of\nHISQ sea quarks. The computation is performed by stochastic estimation of the\ncurrent density using the truncated solver method combined with deflation of\nlow-modes. The parameters are tuned to minimize the computational cost for a\ngiven target uncertainty in the current-current correlation function. The\ncalculation presented here is carried out on a single gauge-field ensemble of\nsize $32^3\\times48$ with an approximate lattice spacing of $\\sim0.15$ fm and\nwith physical sea-quark masses. We describe the methodology and the analysis\nprocedure",
        "positive": "Nucleon electromagnetic form factors in twisted mass lattice QCD: We present results on the nucleon electromagnetic form factors within lattice\nQCD using two flavors of degenerate twisted mass fermions. Volume effects are\nexamined using simulations at two volumes of spatial length L=2.1 fm and L=2.8\nfm. Cut-off effects are investigated using three different values of the\nlattice spacings, namely a=0.089 fm, a=0.070 and a=0.056 fm. The nucleon\nmagnetic moment, Dirac and Pauli radii are obtained in the continuum limit and\nchirally extrapolated to the physical pion mass allowing for a comparison with\nexperiment."
    },
    {
        "anchor": "Spectroscopy of heavy exotic mesons using lattice QCD static potentials\n  and the Born-Oppenheimer approximation: I discuss the investigation of heavy exotic mesons using lattice QCD static\npotentials and the Born-Oppenheimer approximation. I summarize selected recent\nresults for $\\bar{b} \\bar{b} q q$ tetraquarks, for $I = 0$ bottomonium and for\n$I = 1$ bottomonium.",
        "positive": "CP breaking in lattice chiral gauge theories: The CP symmetry is not manifestly implemented for the local and doubler-free\nGinsparg-Wilson operator in lattice chiral gauge theory. We precisely identify\nwhere the effects of this CP breaking appear. We show that they appear in: (I)\nOverall constant phase of the fermion generating functional. (II) Overall\nconstant coefficient of the fermion generating functional. (III) Fermion\npropagator appearing in external fermion lines and the propagator connected to\nYukawa vertices. The first effect appears from the transformation of the path\nintegral measure and it is absorbed into a suitable definition of the constant\nphase factor for each topological sector; in this sense there appears no ``CP\nanomaly''. The second constant arises from the explicit breaking in the action\nand it is absorbed by the suitable weights with which topological sectors are\nsummed. The last one in the propagator is inherent to this formulation and\ncannot be avoided by a mere modification of the projection operator, for\nexample, in the framework of the Ginsparg-Wilson operator. This breaking\nemerges as an (almost) contact term in the propagator when the Higgs field,\nwhich is treated perturbatively, has no vacuum expectation value. In the\npresence of the vacuum expectation value, however, a completely new situation\narises and the breaking becomes intrinsically non-local, though this breaking\nmay still be removed in a suitable continuum limit. This non-local CP breaking\nis expected to persist for a non-perturbative treatment of the Higgs coupling."
    },
    {
        "anchor": "Toward Quantum Computing Phase Diagrams of Gauge Theories with Thermal\n  Pure Quantum States: The phase diagram of strong interactions in nature at finite temperature and\nchemical potential remains largely unexplored theoretically due to inadequacy\nof Monte-Carlo-based computational techniques in overcoming a sign problem.\nQuantum computing offers a sign-problem-free approach but evaluating thermal\nexpectation values is generally resource intensive on quantum computers. To\nfacilitate thermodynamic studies of gauge theories, we propose a generalization\nof thermal-pure-quantum-state formulation of statistical mechanics applied to\nconstrained gauge-theory dynamics, and numerically demonstrate that the phase\ndiagram of a simple low-dimensional gauge theory is robustly determined using\nthis approach, including mapping a chiral phase transition in the model at\nfinite temperature and chemical potential. Quantum algorithms, resource\nrequirements, and algorithmic and hardware error analysis are further discussed\nto motivate future implementations. Thermal pure quantum states, therefore, may\npresent a suitable candidate for efficient thermal-state preparation in gauge\ntheories in the era of quantum computing.",
        "positive": "Multi-Step stochastic correction in dynamical fermion updating\n  algorithms: The advantages of using Multi-Step corrections for simulations of lattice\ngauge theories with dynamical fermions will be discussed. This technique is\nsuited for algorithms based on the Multi-Boson representation of the dynamical\nfermions as well as for the Hybrid Monte-Carlo (HMC) algorithm and variants of\nthe latter, like the Polynomial-HMC. Especially the latter has the power to\ndeal with an odd number of fermion fields--an essential feature necessary for\nrealistic QCD-simulations with up-, down-, and strange-quarks. In particular,\nwe will discuss the application of the multi-step (actually two-step)\ncorrection technique to a PHMC updating algorithm for twisted-mass Wilson\nfermions with non-degenerate fermion masses, as it was used in recent dynamical\nsimulations for N_f=2+1+1 fermion flavors."
    },
    {
        "anchor": "A numerical method to compute derivatives of functions of large complex\n  matrices and its application to the overlap Dirac operator at finite chemical\n  potential: We present a method for the numerical calculation of derivatives of functions\nof general complex matrices. The method can be used in combination with any\nalgorithm that evaluates or approximates the desired matrix function, in\nparticular with implicit Krylov-Ritz-type approximations. An important use case\nfor the method is the evaluation of the overlap Dirac operator in lattice\nQuantum Chromodynamics (QCD) at finite chemical potential, which requires the\napplication of the sign function of a non-Hermitian matrix to some source\nvector. While the sign function of non-Hermitian matrices in practice cannot be\nefficiently approximated with source-independent polynomials or rational\nfunctions, sufficiently good approximating polynomials can still be constructed\nfor each particular source vector. Our method allows for an efficient\ncalculation of the derivatives of such implicit approximations with respect to\nthe gauge field or other external parameters, which is necessary for the\ncalculation of conserved lattice currents or the fermionic force in Hybrid\nMonte-Carlo or Langevin simulations. We also give an explicit deflation\nprescription for the case when one knows several eigenvalues and eigenvectors\nof the matrix being the argument of the differentiated function. We test the\nmethod for the two-sided Lanczos approximation of the finite-density overlap\nDirac operator on realistic $SU(3)$ gauge field configurations on lattices with\nsizes as large as $14\\times14^3$ and $6\\times18^3$.",
        "positive": "QCD Dirac spectrum and components of the gauge field: We analyze the relation between the Dirac spectrum and the gauge field in\nSU(3) lattice QCD. We focus on how components of the gauge field are related to\nthe Dirac spectrum. First, we consider momentum components of the gauge field.\nIt turns out that the broad region of momentum components is relevant for the\nlow-lying Dirac spectrum and zero modes, i.e., topological charges. The\nconnection with chiral random matrix theory is also discussed. Second, we\nconsider an SU(2) subgroup component of the SU(3) gauge field. The SU(2)\nsubgroup component behaves like the SU(2) gauge field in the low-lying Dirac\nspectrum."
    },
    {
        "anchor": "Nucleon Isovector Axial Form Factors: We present results for the isovector axial vector form factors obtained using\nthirteen 2+1+1-flavor highly improved staggered quark (HISQ) ensembles\ngenerated by the MILC collaboration. The calculation of nucleon two- and\nthree-point correlation functions has been done using Wilson-clover fermions.\nIn the analysis of these data, we quantify the sensitivity of the results to\nstrategies used for removing excited state contamination and invoke the\npartially conserved axial current relation between the form factors to choose\nbetween them. Our data driven analysis includes removing contributions from\nmultihadron $N \\pi$ states that make significant contributions. Our final\nresults are: $g_A = 1.295 (50)_\\text{stat}\\,(24)_\\text{sys}$ for the axial\ncharge; $g_S = 1.085 (50)_\\text{stat}\\, (103)_\\text{sys}$ and $g_T = 0.991\n(21)_\\text{stat}\\, (10)_\\text{sys}$ for the scalar and tensor charges; $\\langle\nr_A^2 \\rangle = 0.418 (33)_\\text{stat} (34)_\\text{sys}$ fm${}^2$ for the mean\nsquared axial charge radius, $g_P^\\ast = 9.03(47)_\\text{stat}(42)_\\text{sys} $\nfor the induced pseudoscalar charge; and $g_{\\pi NN} =\n14.14(81)_\\text{stat}(85)_\\text{sys}$ for the pion-nucleon coupling. We also\nprovide a parameterization of the axial form factor $G_A(Q^2)$ over the range\n$0 \\le Q^2 \\le 1$ GeV${}^2$ for use in phenomenology and a comparison with\nother lattice determinations. We find that the various lattice data agree\nwithin 10\\% but are significantly different from the extraction of $G_A(Q^2)$\nfrom the $\\nu$-deuterium scattering data.",
        "positive": "Nucleon Excited States in N$_f$=2 lattice QCD: We investigate the excited states of the nucleon using $N_f=2$ twisted mass\ngauge configurations with pion masses in the range of about 270 MeV to 450 MeV\nand one ensemble of $N_f=2$ Clover fermions at almost physical pion mass. We\nuse two different sets of variational bases and study the resulting generalized\neigenvalue problem. We present results for the two lowest positive and negative\nparity states."
    },
    {
        "anchor": "Exploring the anisotropic HISQ (aHISQ) action: The fate of heavy quarkonia states in quark-gluon plasma is encoded in the\ntemperature dependence of their spectral functions. Reconstruction of spectral\nfunctions from Euclidean lattice correlators is an ill-posed problem. Despite a\nvariety of techniques developed recently, many questions remain unresolved. It\nis known that the situation may be improved using anisotropic ensembles that\nprovide finer resolution in the temporal direction. To date, the effort focused\non Wilson fermions. We report on our first study with anisotropic improved\nstaggered quarks. To compute the spectrum of the anisotropic Highly Improved\nStaggered Quarks (aHISQ) we generated a library of anisotropic pure gauge\nensembles. We discuss the gauge anisotropy tuning that is performed with the\nWilson and Symanzik gradient flow, as well as tuning of the strange quark mass\nand quark anisotropy with aHISQ, using spectrum measurements on quenched\nensembles. Finally, we discuss the impact of anisotropy on pion taste\nsplittings for aHISQ.",
        "positive": "Precise heavy-light meson masses and hyperfine splittings from lattice\n  QCD including charm quarks in the sea: We present improved results for the B and D meson spectrum from lattice QCD\nincluding the effect of u/d,s and c quarks in the sea. For the B mesons the\nHighly Improved Staggered Quark action is used for the sea and light valence\nquarks and NonRelativistic QCD for the b quark including O(\\alpha_s) radiative\ncorrections to many of the Wilson coefficients for the first time. The D mesons\nuse the Highly Improved Staggered Quark action for both valence quarks on the\nsame sea. We find M_{B_s}-M_B=84(2) MeV, M_{B_s}=5.366(8) GeV, M_{B_c}=6.278(9)\nGeV, M_{D_s}=1.9697(33) GeV, and M_{D_s}-M_{D}=101(3) MeV. Our results for the\nB meson hyperfine splittings are M_{B^*}-M_{B}=50(3) MeV,\nM_{B_s^*}-M_{B_s}=52(3) MeV, in good agreement with existing experimental\nresults. This demonstrates that our perturbative improvement of the NRQCD\nchromo-magnetic coupling works for both heavyonium and heavy-light mesons. We\npredict M_{B_c^*}-M_{B_c}=54(3) MeV. We also present first results for the\nradially excited B_c states as well as the orbitally excited scalar B_c0^* and\naxial vector B_c1 mesons."
    },
    {
        "anchor": "Investigation of two-particle contributions to nucleon matrix elements: We investigate contributions of excited states to nucleon matrix elements by\nstudying the two- and three-point functions using nucleon and pion-nucleon\ninterpolating fields. This study is carried out using twisted mass fermion\nensembles with pion masses 346 MeV and 131 MeV. We compare the results obtained\nusing these two ensembles and show preliminary results for nucleon charges.",
        "positive": "N=1 Super Yang-Mills on the Lattice in the Strong Coupling Limit: We study the N=1 supersymmetric SU(N) Yang-Mills theory on the lattice at\nstrong coupling. We analyse and discuss the recent results obtained at strong\ncoupling and large N for the mesonic and fermionic propagators and spectrum."
    },
    {
        "anchor": "RESULTS FOR THE B-MESON DECAY CONSTANT FROM THE APE COLLABORATION: The decay constant for the B-meson in the static limit is calculated using\nthe Wilson and clover actions at various lattice spacings. We show that both\nthe contamination of our results by excited states and the effects finite\nlattice spacing are at most the order of the statistical uncertainties. A\ncomparison is made of our results and those obtained in other studies. Values\nfor $f^{stat}_{B_S}/f^{stat}_B$ and $M_{B_S} - M_B$ are also given.",
        "positive": "Dark matter from one-flavor SU(2) gauge theory: SU(2) gauge theory with a single fermion in the fundamental representation is\na minimal non-Abelian candidate for the dark matter sector, which is presently\nmissing from the standard model. Having only a single flavor provides a natural\nmechanism for stabilizing dark matter on cosmological timescales. Preliminary\nlattice results are presented and discussed in the context of dark matter\nphenomenology."
    },
    {
        "anchor": "Can Sigma Models Describe Finite Temperature Chiral Transitions?: Large-N expansions and computer simulations indicate that the universality\nclass of the finite temperature chiral symmetry restoration transition in the\n3D Gross-Neveu model is mean field theory. This is a counterexample to the\nstandard 'sigma model' scenario which predicts the 2D Ising model universality\nclass. We trace the breakdown of the standard scenario (dimensional reduction\nand universality) to the absence of canonical scalar fields in the model. We\npoint out that our results could be generic for theories with dynamical\nsymmetry breaking, such as Quantum Chromodynamics.",
        "positive": "Numerical Investigation of the 2D N=2 Wess-Zumino Model: We study lattice formulations of the two-dimensional N=2 Wess-Zumino model\nwith a cubic superpotential. Discretizations with and without lattice\nsupersymmetries are compared. We observe that the \"Nicolai improvement\"\nintroduces new problems to simulations of the supersymmetric model. With high\nstatistics we check the degeneracy of bosonic and fermionic masses on the\nlattice. Perturbative mass corrections to one-loop order are compared with\ncontinuum extrapolations of our lattice results in the weakly coupled regime.\nFor intermediate couplings first results of fermionic masses in the continuum\nare presented where deviations from the perturbative result are observed."
    },
    {
        "anchor": "Dynamical Gauge Symmetry Breaking in Strongly Coupled Lattice Theories: We show how a strongly coupled lattice theory consisting of just fermions and\ngauge fields can exhibit a dynamical Higgs mechanism through the formation of a\ngauge invariant four fermion condensate. Furthermore, we argue that this\nlattice Higgs phase may survive into the continuum limit.",
        "positive": "New Higgs physics from the lattice: We report the first results from our comprehensive lattice tool set to\nexplore non-perturbative aspects of Higgs physics in the Standard Model. We\ndemonstrate in Higgs-Yukawa models that Higgs mass lower bounds and upper\nbounds can be determined in lattice simulations when triviality requires the\nnecessity of a finite cutoff to maintain non-zero interactions. The vacuum\ninstability problem is investigated and the lattice approach is compared with\nthe traditional renormalization group procedure which sets similar goals to\ncorrelate lower and upper Higgs mass bounds with the scale of new physics. A\nnovel feature of our lattice simulations is the use of Ginsparg-Wilson fermions\nto represent the effects of Top quark loops in Higgs dynamics. The need for\nchiral lattice fermions is discussed and the approach is extended to full\nTop-Higgs-QCD dynamics. We also report results from our large $N_F$ analysis of\nTop-Higgs Yukawa models to gain analytic insight and to verify our new lattice\ntool set which is deployed in the simulations. The role of non-perturbative\nlattice studies to investigate heavy Higgs particle scenarios is illustrated in\nextensions of the Standard Model."
    },
    {
        "anchor": "Doubly charmed tetraquark: isospin channels and diquark-antidiquark\n  interpolators: We perform a lattice simulation to investigate the doubly charmed tetraquark\n$T^+_{cc}$ observed by the LHCb collaboration, slightly below the $D^{*+}D^0$\nthreshold, with flavor content $cc\\bar{u}\\bar{d}$ and isospin-$0$. Two-meson\ninterpolators are implemented to explore the isospin quantum numbers $I=0$ and\n$I=1$. We observe attraction near the $DD^*$ threshold for $I=0$ and repulsion\nfor $I=1$. Moreover, we also include diquark-antidiquark interpolators to study\ntheir effect on the energy spectrum. There is no significant shift in the\nground state energy when adding diquark-antidiquark interpolators to the\ninterpolator basis when the heavy quark mass is close to the physical charm\nquark mass. However, we observe a non-negligible shift in the second energy\nlevel. This effect has to be taken into account to extract the scattering\namplitude of the $T^+_{cc}$. Finally, with a higher mass (close to the bottom\nquark), the ground state is shifted down significantly. The simulation is\nperformed on $N_f=2+1$ CLS ensembles with $m_\\pi \\simeq 280$ MeV.",
        "positive": "Quark orbital angular momentum in the proton evaluated using a direct\n  derivative method: Quark orbital angular momentum (OAM) in the proton can be calculated directly\ngiven a Wigner function encoding the simultaneous distribution of quark\ntransverse positions and momenta. This distribution can be accessed via proton\nmatrix elements of a quark bilocal operator (the separation in which is Fourier\nconjugate to the quark momentum) featuring a momentum transfer (which is\nFourier conjugate to the quark position). To generate the weighting by quark\ntransverse position needed to calculate OAM, a derivative with respect to\nmomentum transfer is consequently required. This derivative is evaluated using\na direct derivative method, i.e., a method in which the momentum derivative of\na correlator is directly sampled in the lattice calculation, as opposed to\nextracting it a posteriori from the numerical correlator data. The method\nremoves the bias stemming from estimating the derivative a posteriori that was\nseen to afflict a previous exploratory calculation. Data for Ji OAM generated\non a clover ensemble at pion mass $m_{\\pi } = 317\\, \\mbox{MeV} $ are seen to\nagree with the result obtained via the traditional Ji sum rule method. By\nvarying the gauge connection in the quark bilocal operator, also Jaffe-Manohar\nOAM is extracted, and seen to be enhanced significantly compared to Ji OAM."
    },
    {
        "anchor": "Towards fully non-perturbative computation of inelastic $\\ell N$\n  scattering cross sections from lattice QCD: We propose a fully non-perturbative method to compute inelastic\nlepton-nucleon ($\\ell N$) scattering cross sections using lattice QCD. The\nmethod is applicable even at low energies, such as the energy region relevant\nfor the recent and future neutrino-nucleon ($\\nu N$) scattering experiments,\nfor which perturbative analysis is invalidated. The basic building block is the\nforward Compton-scattering amplitude, or the hadronic tensor, computed on a\nEuclidean lattice. Total cross section is constructed from the hadronic tensor\nby multiplying a phase space factor and integrating over the energy and\nmomentum of final hadronic states. The energy integral that induces a sum over\nall possible final states is performed implicitly by promoting the phase space\nfactor to an operator written in terms of the transfer matrix on the lattice.\nThe formalism is imported from that of the inclusive semileptonic B meson decay\n[P. Gambino, S. Hashimoto, arXiv:2005.13730]. It can be generalized to compute\nthe $\\ell N$ scattering cross sections and their moments, as well as the\nvirtual correction to the nuclear $\\beta$-decay. Necessary quark-line\ncontractions for two current insertions corresponding to the Compton amplitude\nto be computed on the lattice are summarized.",
        "positive": "Renormalized Polyakov loop in the Fixed Scale Approach: I compute the deconfinement order parameter for the SU(2) lattice gauge\ntheory, the Polyakov loop, using the fixed scale approach for two different\nscales and show how one can obtain a physical, renormalized, order parameter.\nThe generalization to other gauge theories, including quenched or full QCD, is\nstraightforward."
    },
    {
        "anchor": "Confinement studies in lattice QCD: We describe the current search for confinement mechanisms in lattice QCD. We\nreport on a recent derivation of a lattice Ehrenfest-Maxwell relation for the\nAbelian projection of SU(2) lattice gauge theory. This gives a precise lattice\ndefinition of field strength and electric current due to static sources,\ncharged dynamical fields, gauge fixing and ghosts. In the maximal Abelian gauge\nthe electric charge is anti-screened analogously to the non-Abelian charge.",
        "positive": "Noncompact Lattice Simulations of SU(2) Gauge Theory: Wilson loops have been measured at strong coupling, $\\beta=0.5$, on a $12^4$\nlattice in noncompact simulations of pure SU(2) without gauge fixing. There is\nno sign of quark confinement."
    },
    {
        "anchor": "Tetraquark bound states in the heavy-light heavy-light system: A calculation of the interaction potential of two heavy-light mesons in\nlattice QCD is used to study the existence of tetraquark bound states. The\ninteraction potential of the tetraquark system is calculated on the lattice\nwith 2+1 flavours of dynamical fermions with lattice interpolating fields\nconstructed using colorwave propagators. These propagators provide a new method\nfor constructing all-to-all spatially smeared the interpolating fields, a\ntechnique which allows for a better overlap with the ground state wavefunction\nas well as reduced statistical noise. Potentials are extracted for 24 distinct\nchannels, and are fit with a phenomenological non-relativistic quark model\npotential, from which a determination of the existence of bound states is made\nvia numerical solution of the two body radial Schr\\\"odinger equation.",
        "positive": "The universal effective potential for three-dimensional massive scalar\n  field theory from the Monte Carlo study of the Ising model: We study the low-energy effective action $S_{eff}[\\varphi]$ for the\none-component real scalar field theory in three Euclidean dimensions in the\nsymmetric phase, concentrating on its static part --- effective potential\n$V_{eff}(\\varphi)$. It characterizes the approach to the phase transition in\nall systems that belong to the 3d Ising universality class. We compute it from\nthe probability distributions of the average magnetization in the 3d Ising\nmodel in a homogeneous external field, obtained by Monte Carlo. We find that\nthe $\\varphi^6$ term in $V_{eff}$ is important, while the higher terms can be\nneglected within our statistical errors. Thus we obtain the approximate\neffective action $$ S_{eff} = \\int d^3 x \\left\\{\n  {1 \\over 2} \\partial_\\mu \\varphi \\partial_\\mu \\varphi +\n  {1 \\over 2} m^2 \\varphi^2 + m g_4 \\varphi^4 + g_6 \\varphi^6 \\right\\} , $$\nwith arbitrary mass $m$ that sets the scale, and dimensionless couplings $g_4 =\n0.97 \\pm 0.02$ and $g_6 = 2.05 \\pm 0.15$. The value of $g_4$ is consistent with\nthe renormalization group fixed point coupling. This $V_{eff}$, when used\ninstead of the traditional $a \\varphi^2 + b \\varphi^4$, turns the\nGinzburg--Landau description of the long-wave properties of the 3d theory near\ncriticality into quantitatively accurate. It is also relevant to the theory of\ncosmological phase transitions."
    },
    {
        "anchor": "Heavy Flavors on the Lattice: The lattice QCD results on the hadron spectrum and weak transitions between\nhadrons are briefly reviewed. Hadrons containing heavy quarks c or b are\nconsidered. The focus is on the recent simulations and some older results which\nare particularly relevant in view of the recent experimental discoveries.",
        "positive": "Color confinement and dual superconductivity of the vacuum. III: It is demonstrated that monopole condensation in the confined phase of SU(2)\nand SU(3) gauge theories is independent of the specific Abelian projection used\nto define the monopoles. Hence the dual excitations which condense in the\nvacuum to produce confinement must have magnetic U(1) charge in all the Abelian\nprojections. Some physical implications of this result are discussed."
    },
    {
        "anchor": "On the $\u03b2$- and quark mass dependence of the nuclear transition in\n  the strong coupling regime: Lattice QCD in a dual formulation with staggered fermions is well established\nin the strong coupling limit and allows to perform Monte Carlo simulations at\nfinite baryon chemical potential. We have recently addressed the dependence of\nthe nuclear critical end point as a function of the quark mass $am_q$, and\nseparately as a function of the lattice gauge coupling $\\beta$ in the chiral\nlimit. Here we proceed to determine the dependence of the nuclear transition on\nboth, $am_q$ and $\\beta$, on isotropic lattices and attempt to pinpoint the\ncritical end point for various $\\beta$ where the sign problem is still\nmanageable.",
        "positive": "The Lambert W Function, Laguerre Polynomials, and the Zeros of the QCD\n  Partition Function: We study solutions of a transcendental equation for the complex chemical\npotential at which a random-matrix QCD model can undergo a phase transition at\nzero mass. An explicit solution is obtained in terms of the Lambert W function.\nWe also provide a closed form expression for a QCD random matrix model\npartition function, as a sum of Laguerre polynomials, for complex chemical\npotential and non-zero mass."
    },
    {
        "anchor": "Comparison of Inversion Algorithms for Wilson Fermions on the CM5: This talk presents results of a comparitive study of iterative algorithms\nlike minimal residue ($MR$) and conjugate gradient ($CG$, $BiCG\\gamma_5$, and\n\\bicgstab) used for inverting the Dirac matrix $M$. The tests were done on the\nConnection Machine CM-5 using $32^3 \\times 64$ lattices. The fermion action\nused is of Wilson type, both with and without the clover term. The overall\nconclusion is that preconditioned over-relaxed $MR$ is the simplest, uses the\nleast memory, and is comparable in performance to \\bicgstab. We find these two\nalgorithms to be equally robust, $i.e.$ insensitive to the starting solution\nand to round-off errors.",
        "positive": "Cooling, Physical Scales and Topology: We develop a cooling method controlled by a physical cooling radius that\ndefines a scale below which fluctuations are smoothed out while leaving physics\nunchanged at all larger scales. We apply this method to study topological\nproperties of lattice gauge theories, in particular the behaviour of\ninstantons, dislocations and instanton--anti-instanton pairs. Monte Carlo\nresults for the SU(2) topology are presented. We find that the method provides\na means to prevent instanton--anti-instanton annihilation under cooling. While\nthe instanton sizes are largely independent from the smoothing scale, the\ndensity and pair separations are determined by the particular choice made for\nthis quantity. We discuss the questions this raises for the \"physicality\" of\nthese concepts."
    },
    {
        "anchor": "The Saga of Landau-Gauge Propagators: Gathering New Ammo: Compelling evidence has recently emerged from lattice simulations in favor of\nthe massive solution of the Schwinger-Dyson equations of Landau-gauge QCD. The\nmain objections to these lattice results are based on possible Gribov-copy\neffects. We recently installed at IFSC-USP a new GPU cluster dedicated to the\nstudy of Green's functions. We present here our point of view on the Saga and\nthe status of our project. We also show data for the 2D case on a 2560^2\nlattice.",
        "positive": "Leptonic B- and D-meson decay constants with 2+1 flavors of asqtad\n  fermions: We present the status of our updated D- and B-meson decay-constant analysis,\nbased on the MILC $N_f = 2+1$ asqtad gauge ensembles. Heavy quarks are\nincorporated using the Wilson clover action with the Fermilab interpretation.\nThis analysis includes ensembles at five lattice spacings from a $\\approx$\n0.045 to 0.15 fm, and light sea-quark masses down to 1/20th of the\nstrange-quark mass. Projected error budgets for ratios of decay constants, in\nparticular between bottom- and charm-meson decay constants, are presented."
    },
    {
        "anchor": "Tensor renormalization group analysis of ${\\rm CP}(N-1)$ model in two\n  dimensions: We apply the higher order tensor renormalization group to lattice CP($N-1$)\nmodel in two dimensions. A tensor network representation of CP($N-1$) model is\nderived. We confirm that the numerical results of the CP(1) model without the\n$\\theta$-term using this method are consistent with that of the O(3) model\nwhich is analyzed by the same method in the region $\\beta \\gg 1$ and that\nobtained by Monte Carlo simulation in a wider range of $\\beta$.",
        "positive": "Nucleon isovector scalar charge from overlap fermions: We calculate the nucleon isovector scalar charge in lattice QCD using overlap\nfermions on five ensembles of gauge configurations generated by the RBC/UKQCD\ncollaboration using the domain-wall quark action with $2+1$ dynamical flavors.\nThe five ensembles cover five pion masses, $m_\\pi \\approx$ 139, 171, 302, 337\nand 371 MeV, and four lattice spacings, $a \\approx $ 0.06, 0.08, 0.11 and 0.14\nfm. Three to six valence quark masses are computed on each ensemble to\ninvestigate the pion mass dependence. The extrapolation to the physical pion\nmass, continuum and infinite volume limits is obtained by a global fit of all\ndata to a formula originated from partially quenched chiral perturbation\ntheory. The excited-states contamination is carefully analyzed with 3--5\nsink-source separations and multi-state fits. Our final result, in the\n$\\overline{\\text{MS}}$ scheme at 2 GeV, is $g_{S}^{u-d}= 0.94\n(10)_{stat}(8)_{sys}$, where the first error is the statistical error and the\nsecond is the systematic error."
    },
    {
        "anchor": "Ground-state energy shift of n pions and m kaons in a finite volume: The ground state energy of a collection of n pions and m kaons with short\nrange interactions is calculated for a volume with finite spatial extent L and\nperiodic boundary conditions. This calculation is accomplished to order L^-6 in\nthe large volume expansion. With this result one can extract the various two-\nand three-body interactions between pions and kaons from lattice QCD data.",
        "positive": "Strong coupling series for QCD at finite temperature and density: We discuss the use of strong coupling expansions for Yang-Mills theory and\nQCD at finite temperature and density. In particular we consider the onset of\ntemperature effects for the free energy and screening masses, derive the hadron\nresonance gas model from first principles and compute the weakening of the\ndeconfinement transition with chemical potential."
    },
    {
        "anchor": "Gauge-invariant implementation of the Abelian Higgs model on optical\n  lattices: We present a gauge-invariant effective action for the Abelian Higgs model\n(scalar electrodynamics) with a chemical potential $\\mu$ on a 1+1 dimensional\nlattice. This formulation provides an expansion in the hopping parameter\n$\\kappa$ which we test with Monte Carlo simulations for a broad range of the\ninverse gauge coupling $\\beta_{pl}$ and small values of the scalar\nself-coupling $\\lambda$. In the opposite limit of infinitely large $\\lambda$,\nthe partition function can be written as a traced product of local tensors\nwhich allows us to write exact blocking formulas. Their numerical\nimplementation requires truncations but there is no sign problem for arbitrary\nvalues of $\\mu$. We show that the time continuum limit of the blocked transfer\nmatrix can be obtained numerically and, in the limit of infinite $\\beta_{pl}$\nand with a spin-1 truncation, the small volume energy spectrum is identical to\nthe low energy spectrum of a two-species Bose-Hubbard model in the limit of\nlarge onsite repulsion. We extend this procedure for finite $\\beta_{pl}$ and\nderive a spin-1 approximation of the Hamiltonian. It involves new terms\ncorresponding to transitions among the two species in the Bose-Hubbard model.\nWe propose an optical lattice implementation involving a ladder structure.",
        "positive": "Lattice QCD study of confinement and chiral symmetry breaking with\n  Dirac-mode expansion: Using the eigen-mode of the QCD Dirac operator $\\Slash D=\\gamma^\\mu D^\\mu$,\nwe develop a manifestly gauge-covariant expansion and projection of the QCD\noperators such as the Wilson loop and the Polyakov loop. With this method, we\nperform a direct analysis of the correlation between confinement and chiral\nsymmetry breaking in lattice QCD Monte Carlo calculations. Even after removing\nthe low-lying Dirac modes, which are responsible to chiral symmetry breaking,\nwe find that the Wilson loop obeys the area law, and the string tension or the\nconfinement force is almost unchanged. We find also that the Polyakov loop\nremains to be almost zero even without the low-lying Dirac modes, which\nindicates the Z_3-unbroken confinement phase. These results indicate that\none-to-one correspondence does not hold between confinement and chiral symmetry\nbreaking in QCD."
    },
    {
        "anchor": "Lattice Computation of the Effective Potential in O(2)-Invariant\n  $\u03bb\u03a6^4$ Theory: We present a lattice computation of the effective potential for\nO(2)-invariant $(\\lambda\\Phi^4)_4$ theory in the region of bare parameters\ncorresponding to a classically scale-invariant theory. As expected from\n``triviality'' and as in the one-component theory, we find very good agreement\nwith the one-loop prediction, while a perturbative leading-log improvement of\nthe effective potential fails to reproduce the Monte Carlo data. The mass $m_h$\nof the free shifted radial field is related to the renormalized vacuum\nexpectation value $v_R$ through the same relation $m^2_h=8\\pi^2 v^2_R$ as in\nthe one-component case. This confirms the prediction of a weakly interacting\n2.2 TeV Higgs particle in the standard model.",
        "positive": "Low-mode averaging for baryon correlation functions: The low-mode averaging technique is a powerful tool for reducing large\nfluctuations in correlation functions due to low-mode eigenvalues of the Dirac\noperator. In this work we propose a generalization to baryons and test our\nmethod on two-point correlation functions of left-handed nucleons, computed\nwith quenched Neuberger fermions on a lattice with extension L=1.5 fm. We show\nthat the statistical fluctuations can be reduced and the baryon signal\nsignificantly improved."
    },
    {
        "anchor": "On The Deconfinement Transition in SU(4) Lattice Gauge Theory: The deconfinement transition in SU(4) lattice gauge theory is investigated on\nN_s^3 X N_t lattices for N_s = 8-16 and N_t = 4-8 using a modified Wilson\naction which is expected to be free of any bulk transitions. The susceptibility\nchi_{|L|}^{max}, where L is the order parameter for deconfinement, is found to\nincrease linearly with spatial volume for N_t = 4, 5, and 6, indicating a first\norder deconfinement phase transition. The latent heat of the transition is\nestimated to be approximately 2/3 of the corresponding ideal gas energy density\nat T_c.",
        "positive": "Towards Highly Improved Quark Actions: We describe two ideas useful in the construction of highly improved quark\nactions for simulations on coarse lattices:\n  (1) Field transformations to solve the doubler problem without destroying\ntree-level improvement for on- or off-shell quantities.\n  (2) Anisotropic lattices with smaller temporal than spatial lattice spacing.\nWe present first simulation results for the quenched light hadron and\ncharmonium spectra obtained with a D234 action on anisotropic lattices."
    },
    {
        "anchor": "The HAL QCD potential in $I=1$ $\u03c0\u03c0$ system with the $\u03c1$ meson\n  bound state: In this paper, we investigate the HAL QCD potential in the $I=1$ $\\pi \\pi$\nscattering using the hybrid method for all-to-all propagators, in which a\npropagator is approximated by low-eigenmodes and the remaining high-eigenmode\npart is stochastically estimated. To verify the applicability of the hybrid\nmethod to systems containing quark creation$/$annihilation contributions such\nas the $\\rho$ meson, we calculate the $I=1$ $\\pi\\pi$ potential with the 2+1\nflavor gauge configurations on $16^3 \\times 32$ lattice at the lattice spacing\n$a \\approx 0.12$ fm and $(m_{\\pi},m_{\\rho}) \\approx (870, 1230)$ MeV, in which\nthe $\\rho$ meson appears as a deeply-bound state. While we find that the naive\nstochastic evaluations for quark creation$/$annihilation contributions lead to\nextremely large statistical fluctuations, additional noise reduction methods\nenable us to obtain a sufficiently precise potential, which shows a strong\nattractive force. We also confirm that the binding energy and $k^3 \\cot \\delta$\nobtained from our potential are roughly consistent with an existing $\\rho$\nmeson bound state, within a large systematic error associated with our\ncalculation, whose possible origin is also discussed.",
        "positive": "A further study of the possible scaling region of lattice chiral\n  fermions: In the possible scaling region for an SU(2) lattice chiral fermion advocated\nin {\\it Nucl. Phys.} B486 (1997) 282, no hard spontaneous symmetry breaking\noccurs and doublers are gauge-invariantly decoupled via mixing with composite\nthree-fermion-states that are formed by local multifermion interactions.\nHowever the strong coupling expansion breaks down due to no ``static limit''\nfor the low-energy limit ($pa\\sim 0$). In both neutral and charged channels, we\nfurther analyze relevant truncated Green functions of three-fermion-operators\nby the strong coupling expansion and analytical continuation of these Green\nfunctions in the momentum space. It is shown that in the low-energy limit,\nthese relevant truncated Green functions of three-fermion-states with the\n``wrong'' chiralities positively vanish due to the generalized form factors\n(the wave-function renormalizations) of these composite three-fermion-states\nvanishing as O((pa)^4) for $pa\\sim 0$. This strongly implies that the composite\nthree-fermion-states with ``wrong'' chirality are ``decoupled'' in this limit\nand the low-energy spectrum is chiral, as a consequence, chiral gauge\nsymmetries can be exactly preserved."
    },
    {
        "anchor": "Strong dynamics, composite Higgs and the conformal window: We review recent progress in the lattice investigations of near-conformal\nnon-abelian gauge theories relevant for dynamical symmetry breaking and model\nbuilding of composite Higgs models. The emphasis is placed on the mass spectrum\nand the running renormalized coupling. The role of a light composite scalar\nisosinglet particle as a composite Higgs particle is highlighted.",
        "positive": "Perturbative Renormalisation of the Second Moment of Generalised Parton\n  Distributions: We calculate the non-forward quark matrix elements of operators with two\ncovariant derivatives needed for the renormalisation of the second moment of\ngeneralised parton distributions in one-loop lattice perturbation theory using\nWilson fermions. For some representations of the hypercubic group commonly used\nin simulations we determine the sets of all possible mixing operators. For\nthose representations the one-loop mixing matrices of renormalisation factors\nare found. Due to non-vanishing contributions of operators with external\nordinary derivatives the number of contributing operators increases compared to\nforward matrix elements."
    },
    {
        "anchor": "Regularization and Anomalies in Gauge Theory: Some of the basic issues related to the regularization and anomalies in gauge\ntheory are reviewed, with particular emphasis on the recent development in\nlattice gauge theory. The generalized Pauli-Villars regularization is discussed\nfrom a view point of the covariant regularization of currents, and the\nconstruction of a regularized effective action in terms of covariant currents\nis compared with the lattice formulation of chiral Abelian theory.",
        "positive": "Incorporating $DD\u03c0$ effects and left-hand cuts in lattice QCD studies\n  of the $T_{cc}(3875)^+$: We generalize the relativistic field-theoretic three-particle finite-volume\nscattering formalism to describe generic $DD\\pi$ systems in the charm $C=2$\nsector. This includes the isospin-0 channel, in which the recently discovered\ndoubly-charmed tetraquark $T_{cc}(3875)^+$ is expected to manifest as a pole in\nthe $DD \\pi \\to DD \\pi$ scattering amplitude. The formalism presented here can\nalso be applied to lattice QCD settings in which the $D^*$ is bound and, in\nparticular, remains valid below the left-hand cut in $D D^*$ scattering, thus\nresolving an issue in previous analyses of lattice-determined finite-volume\nenergies."
    },
    {
        "anchor": "Testing Topology Conserving Gauge Actions for Lattice QCD: We explore gauge actions for lattice QCD, which are constructed such that the\noccurrence of small plaquette values is strongly suppressed. Such actions\noriginate from the admissibility condition in order to conserve the topological\ncharge. The suppression of small plaquette values is expected to be\nadvantageous for numerical studies in the $\\epsilon$-regime and also for\nsimulations with dynamical quarks. Performing simulations at a lattice spacing\nof about 0.1 fm, we present numerical results for the static potential, the\nphysical scale $r_0$, the stability of the topological charge history, the\ncondition number of the kernel of the overlap operator and the acceptance rate\nagainst the step size in the local HMC algorithm.",
        "positive": "FK/Fpi from the Budapest-Marseille-Wuppertal Collaboration: Based on a series of lattice calculations we determine the ratio FK/Fpi in\nQCD. With experimental data from kaon decay and nuclear double beta decay, we\nobtain a precise determination of |Vus|. Our simulation includes 2+1 flavours\nof sea quarks, with three lattice spacings, large volumes and a simulated pion\nmass reaching down to about 190 MeV for a full control over the systematic\nuncertainties."
    },
    {
        "anchor": "Equation of State for the SU(3) Gauge Theory: Through a detailed investigation of the $SU(3)$ gauge theory at finite\ntemperature on lattices of various size we can control finite lattice cut-off\neffects in bulk thermodynamic quantities. We calculate the pressure and energy\ndensity of the $SU(3)$ gauge theory on lattices with temporal extent $N_\\tau =\n4$, 6 and 8 and spatial extent $N_\\sigma =16$ and 32. The results are\nextrapolated to the continuum limit. We find a deviation from ideal gas\nbehaviour of (15-20)\\%, depending on the quantity, even at temperatures as high\nas $T\\sim 3T_c$. A calculation of the critical temperature on lattices with\ntemporal extent $N_\\tau = 8$ and 12 and the string tension on $32^4$ lattices\nat the corresponding critical couplings is performed to fix the temperature\nscale. An extrapolation to the continuum limit yields $T_c/\\sqrt{\\sigma} =\n0.629(3)$.",
        "positive": "The Strong CP Problem in the Quantum Rotor: Recent studies have claimed that the strong CP problem does not occur in QCD,\nproposing a new order of limits in volume and topological sectors when studying\nobservables on the lattice. In order to shed light on this issue, we study the\neffect of the topological $\\theta$-term on a simple quantum mechanical rotor\nthat allows a lattice description. The topological susceptibility and the\n$\\theta$-dependence of the energy spectrum are both computed using local\nlattice correlation functions. The sign problem is overcome by considering\nTaylor expansions in $\\theta$ exploiting automatic differentiation methods for\nMonte Carlo processes. Our findings confirm the conventional wisdom on the\nstrong CP problem."
    },
    {
        "anchor": "The Index Theorem and Random Matrix Theory for Improved Staggered Quarks: We study various improved staggered quark Dirac operators on quenched gluon\nbackgrounds in lattice QCD. We find a clear separation of the spectrum of\neigenvalues into high chirality, would-be zero modes and others, in accordance\nwith the Index Theorem. We find the expected clustering of the non-zero modes\ninto quartets as we approach the continuum limit. The predictions of random\nmatrix theory for the epsilon regime are well reproduced. We conclude that\nimproved staggered quarks near the continuum limit respond correctly to QCD\ntopology.",
        "positive": "Symmetry, Confinement and the phase diagram of QCD: A general discussion is presented of the possible symmetries responsible for\nconfinement of color and of their evidence in lattice simulations. The\nconsequences on the phase diagram of $QCD$ are also analyzed."
    },
    {
        "anchor": "Matching Current Correlators in Lattice QCD to Chiral Perturbation\n  Theory: Chiral perturbation theory gives direct and unambiguous predictions for the\nform of various two-point hadronic correlators at low momentum in terms of a\nfinite set of couplings in a chiral Lagrangian. In this paper we study the\nfeasibility of extracting the couplings in the chiral Lagrangian (through\n1-loop order) by fitting two-point correlators computed in lattice QCD to the\npredicted chiral form. The correlators are computed using a pseudofermion\ntechnique yielding all-point quark propagators which allows the computation of\nthe full four-momentum transform of the two-point functions to be obtained\nwithout sacrificing any of the physical content of the unquenched gauge\nconfigurations used. Results are given for an ensemble of dynamical\nconfigurations generated using the truncated determinant algorithm on a large\ncoarse lattice. We also present a new analysis of finite volume effects based\non a finite volume dimensional regularization scheme which preserves the\npower-counting rules appropriate for a chiral Lagrangian.",
        "positive": "On the chiral limit in lattice gauge theories with Wilson fermions: The chiral limit $~\\kappa \\simeq \\kappa_c(\\beta)~$ in lattice gauge theories\nwith Wilson fermions and problems related to near--to--zero ('exceptional')\neigenvalues of the fermionic matrix are studied. For this purpose we employ\ncompact lattice QED in the confinement phase. A new estimator $~\\mpr_{\\pi}~$\nfor the calculation of the pseudoscalar mass $~m_{\\pi}~$ is proposed which does\nnot suffer from 'divergent' contributions at $\\kappa \\simeq \\kappa_c(\\beta)$.\nWe conclude that the main contribution to the pion mass comes from larger\nmodes, and 'exceptional' eigenvalues play {\\it no} physical role. The behaviour\nof the subtracted chiral condensate $~\\langle \\psb \\psi \\rangle_{subt}~$ near\n$~\\kappa_c(\\beta)~$ is determined. We observe a comparatively large value of\n$~\\langle \\psb \\psi \\rangle_{subt} \\cdot Z_P^{-1}~$, which could be interpreted\nas a possible effect of the quenched approximation."
    },
    {
        "anchor": "The Heavy Quark Self-Energy in Nonrelativistic Lattice QCD: The heavy quark self-energy in nonrelativistic lattice QCD is calculated to\n$O(\\alpha_s)$ in perturbation theory. An action which includes all\nspin-independent relativistic corrections to order $v^2$, where $v$ is the\ntypical heavy quark velocity, and all spin-dependent corrections to order $v^4$\nis used. The standard Wilson action and an improved multi-plaquette action are\nused for the gluons. Results for the mass renormalization, wavefunction\nrenormalization, and energy shift are given; tadpole contributions are found to\nbe large. A tadpole improvement scheme in which all link variables are rescaled\nby a mean-field factor is also studied. The effectiveness of this scheme in\noffsetting the large tadpole contributions to the heavy quark renormalization\nparameters is demonstrated.",
        "positive": "Twisted mass chiral perturbation theory at next-to-leading order: We study the properties of pions in twisted mass lattice QCD (with two\ndegenerate flavors) using chiral perturbation theory (ChPT). We work to\nnext-to-leading order (NLO) in a power counting scheme in which m_q ~ a\n\\Lambda_QCD^2, with m_q the physical quark mass and a the lattice spacing. We\nargue that automatic O(a) improvement of physical quantities at maximal twist,\nwhich has been demonstrated in general if m_q >> a \\Lambda_QCD^2, holds even if\nm_q ~ a \\Lambda_QCD^2, as long as one uses an appropriate non-perturbative\ndefinition of the twist angle. We demonstrate this with explicit calculations,\nfor arbitrary twist angle, of all pionic quantities that involve no more than a\nsingle pion in the initial and final states: masses, decay constants, form\nfactors and condensates, as well as the differences between alternate\ndefinitions of twist angle. We also calculate the axial and pseudoscalar form\nfactors of the pion, quantities which violate flavor and parity, and which\nvanish in the continuum limit. These are of interest because they are not\nautomatically O(a) improved at maximal twist. They allow a determination of the\nunknown low energy constants introduced by discretization errors, and provide\ntests of the accuracy of ChPT at NLO. We extend our results into the regime\nwhere m_q ~ a^2 \\Lambda_QCD^3, and argue in favor of a recent proposal that\nautomatic O(a) improvement at maximal twist remains valid in this regime."
    },
    {
        "anchor": "Finite-density QCD, $\\mathcal{PT}$ symmetry, and exotic phases: We study the phase structure of effective models of finite-density QCD using\nanalytic and lattice simulation techniques developed for the study of\nnon-Hermitian and $\\mathcal{PT}$-symmetric QFTs. Finite-density QCD is\nsymmetric under the combined operation of the charge and complex conjugation\noperators $\\mathcal{CK}$, which falls into the class of so-called generalized\n$\\mathcal{PT}$ symmetries. We show that $\\mathcal{PT}$-symmetric quantum field\ntheories can support patterned ground-state field configurations in the\nvicinity of a critical endpoint. We apply our methods to a lattice heavy quark\nmodel at nonzero chemical potential that displays patterning behavior for a\nrange of parameters. We derive a simple approximate criterion for the formation\nof these patterns, which can be used with lattice results.",
        "positive": "Vortices in equilibrium scalar electrodynamics: Scalar electrodynamics can be used to investigate the formation of cosmic\nstrings in the early universe. We present the results of lattice Monte Carlo\nsimulations of an effective three-dimensional U(1)+Higgs theory that describes\nthe equilibrium properties of finite-temperature scalar electrodynamics near\nthe transition. A gauge-invariant criterion for the existence of a vortex is\nused in measuring the properties of the vortex network in the equilibrium state\nboth in the Coulomb and in the Higgs phase of the system. The naive definition\nof the vortex density becomes meaningless in the continuum limit and special\ncare is needed in extracting physical quantities. Numerical evidence for a\nphysical discontinuity in the vortex density is given."
    },
    {
        "anchor": "Taste symmetry breaking with HYP-smeared staggered fermions: We study the impact of hypercubic (HYP) smearing on the size of taste\nbreaking for staggered fermions, comparing to unimproved and to asqtad-improved\nstaggered fermions. As in previous studies, we find a substantial reduction in\ntaste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on\nlattices with spacing $a\\approx 0.1 $fm). In addition, we observe that\ndiscretization effects of next-to-leading order in the chiral expansion (${\\cal\nO}(a^2 p^2)$) are markedly reduced by HYP smearing. Compared to asqtad valence\nfermions, we find that taste-breaking in the pion spectrum is reduced by a\nfactor of 2.5-3, down to a level comparable to the expected size of generic\n${\\cal O}(a^2)$ effects. Our results suggest that, once one reaches a lattice\nspacing of $a\\approx 0.09 $fm, taste-breaking will be small enough after HYP\nsmearing that one can use a modified power counting in which ${\\cal O}(a^2) \\ll\n{\\cal O}(p^2)$, simplify fitting to phenomenologically interesting quantities.",
        "positive": "A Lattice Story of Proton Spin: In this contribution, I summarized the recent Lattice QCD consensuses on the\nquark helicity, plus the investigations on the gluon helicity and orbital\nangular momenta. The preliminary non-perturbative normalized and renormalized\nJi quark and gluon angular momentum results are also reported and compared with\nthe previous 1-loop perturbative renormalized results."
    },
    {
        "anchor": "Large N QCD in two dimensions with a baryonic chemical potential: We consider large N gauge theory on a two dimensional lattice in the presence\nof a baryonic chemical potential. We work with one copy of naive fermion and\nargue that reduction holds even in the presence of a chemical potential.\nAnalytical arguments supported by numerical studies show that there is no phase\ntransition as a function of the baryonic chemical potential.",
        "positive": "Effect of the Schr\u00f6dinger functional boundary conditions on the\n  convergence of step scaling: Recently several lattice collaborations have studied the scale dependence of\nthe coupling in theories with different gauge groups and fermion\nrepresentations using the Schr\\\"odinger functional method. This has motivated\nus to look at the convergence of the perturbative step scaling to its continuum\nlimit with gauge groups SU(2) and SU(3) with Wilson fermions in the\nfundamental, adjoint or sextet representations. We have found that while the\nimproved Wilson action does remove the linear terms from the step scaling, the\nconvergence is extremely slow with the standard choices of the boundary\nconditions for the background field. We show that the situation can be improved\nby careful choice of the boundary fields."
    },
    {
        "anchor": "Overlap for 2D chiral U(1) models: The overlap formulation is applied to an anomaly free combination of chiral\nfermions coupled to U(1) gauge fields on a 2D torus. Evidence is presented that\ngauge averaging the overlap phases in these models produces correct continuum\nresults.",
        "positive": "Portable QCD codes for Massively Parallel Processors. UKQCD\n  collaboration: We present a new set of QCD codes in both message passing and data parallel\nversions. The message passing package used is PARMACS, although other packages\nmay be used. Data parallel software is written in High Performance fortran, an\nemerging standard based on Fortran 90. Software engineering methods have been\napplied to a physics application to create thoroughly tested and documented\ncodes for the next generation of massively parallel supercomputers."
    },
    {
        "anchor": "Partially quenched chiral perturbation theory in the epsilon-regime: We calculate meson correlators in the epsilon-regime within partially\nquenched chiral perturbation theory. The valence quark masses and sea quark\nmasses can be chosen arbitrary and all non-degenerate. Taking some of the sea\nquark masses to infinity, one obtains a smooth connection among the theories\nwith different number of flavors, as well as the quenched theory. These results\ncan be directly compared with lattice QCD simulations.",
        "positive": "Curvature of the chiral pseudo-critical line in QCD: continuum\n  extrapolated results: We determine the curvature of the pseudo-critical line of strong interactions\nby means of numerical simulations at imaginary chemical potentials. We consider\n$N_f=2+1$ stout improved staggered fermions with physical quark masses and the\ntree level Symanzik gauge action, and explore four different sets of lattice\nspacings, corresponding to $N_t = 6,8,10,12$, in order to extrapolate results\nto the continuum limit. Our final estimate is $\\kappa = 0.0135(20)$."
    },
    {
        "anchor": "$\u03c1$ mesons in strong abelian magnetic field in SU(3) lattice gauge\n  theory: We explore the masses of neutral and charged $\\rho$ mesons in strong abelian\nmagnetic field in $SU(3)$ gluodynamics. The behaviour of the ground state\nenergy of these particles in the external magnetic field depends on its spin\nprojection $s_z$ on the axis of external magnetic field. The masses of $\\rho^0$\nmeson with $s_z=\\pm 1$ increase with the field. The masses of $\\rho^{\\pm}$\nmesons with zero spin also grow with the magnetic field. The ground state\nenergies of $\\rho^{-}$ meson with $s_z=-1$ and $\\rho^{+}$ meson with $s_z=+1$\ndiminish as a function of the field, while the energies of $\\rho^{+}$ meson\nwith $s_z=-1$ and $\\rho^{-}$ meson with $s_z=+1$ rise with the field value.",
        "positive": "Two-current correlations in the pion on the lattice: We perform a systematic study of the correlation functions of two quark\ncurrents in a pion using lattice QCD. We obtain good signals for all but one of\nthe relevant Wick contractions of quark fields. We investigate the quark mass\ndependence of our results and test the importance of correlations between the\nquark and the antiquark in the pion. Our lattice data are compared with\npredictions from chiral perturbation theory."
    },
    {
        "anchor": "Chiral perturbation theory, dispersion relations and final state\n  interactions in K -> pi pi: We discuss the recent literature on the treatment of final state interactions\nin K -> pi pi. Various approaches are compared and particular emphasis is given\nto the possibility of combining dispersive methods with lattice input. Recent\nresults on the dependence of various quantities on the quark masses at order\np^6 in the chiral expansion are presented and the relevance for the lattice\ncalculations is discussed.",
        "positive": "LQCD at non zero isospin chemical potential: Systems of non-zero isospin chemical potential are studied from a canonical\napproach by computing correlation functions with the quantum numbers of $N\n\\pi^+$'s ($C_{N \\pi}$). In order to reduce the number of contractions required\nin calculating $C_{N \\pi}$ for a large $N$ in the Wick's theorem, we\nconstructed a few new algorithms. With these new algorithms, systems with\nisospin charge up to 72 are investigated on three anisotropic gauge ensembles\nwith a pion mass of $390 \\rm{MeV}$, and with lattice spatial extents $L \\sim\n{2.0, 2.5, 3.0} \\rm{fm}$. The largest isospin density of $\\rho_I \\approx 9\n\\rm{fm}^{-3}$ is achieved in the smallest volume, and the QCD phase diagram is\ninvestigated at a fixed low temperature at varying isospin chemical potentials,\n$m_{\\pi} \\le \\mu_I \\le 4.5 m_{\\pi}$. By investigating the behaviour of the\nextracted energy density of the system at different isospin chemical\npotentials, we numerically identified the conjectured transition to a\nBose-Einstein condensation state at $\\mu_I \\ge m_{\\pi}$."
    },
    {
        "anchor": "Casimir scaling of domain wall tensions in the deconfined phase of D=3+1\n  SU(N) gauge theories: We perform lattice calculations of the spatial 't Hooft k-string tensions in\nthe deconfined phase of SU(N) gauge theories for N=2,3,4,6. These equal (up to\na factor of T) the surface tensions of the domain walls between the\ncorresponding (Euclidean) deconfined phases. For T much larger than Tc our\nresults match on to the known perturbative result, which exhibits Casimir\nScaling, being proportional to k(N-k). At lower T the coupling becomes stronger\nand, not surprisingly, our calculations show large deviations from the\nperturbative T-dependence. Despite this we find that the behaviour proportional\nto k(N-k) persists very accurately down to temperatures very close to Tc. Thus\nthe Casimir Scaling of the 't Hooft tension appears to be a `universal' feature\nthat is more general than its appearance in the low order high-T perturbative\ncalculation. We observe the `wetting' of these k-walls at T around Tc and the\n(almost inevitable) `perfect wetting' of the k=N/2 domain wall. Our\ncalculations show that as T tends to Tc the magnitude of the spatial `t Hooft\nstring tension decreases rapidly. This suggests the existence of a (would-be)\n't Hooft string condensation transition at some temperature which is close to\nbut below Tc. We speculate on the `dual' relationship between this and the\n(would-be) confining string condensation at the Hagedorn temperature that is\nclose to but above Tc.",
        "positive": "Form factors for the decay processes $B_c^+ \\to D^0 \\ell^+ \u03bd_{\\ell}$\n  and $B_c^+ \\to D_s^+ \\ell^+ \\ell^-$ from lattice QCD: We present results of the first lattice QCD calculations of the weak matrix\nelements for the decays $B_c^+ \\to D^0 \\ell^+ \\nu_{\\ell}$, $B_c^+ \\to D_s^+\n\\ell^+ \\ell^-$ and $B_c^+ \\to D_s^+ \\nu \\overline{\\nu}$. Form factors across\nthe entire physical $q^2$ range are then extracted and extrapolated to the\ncontinuum limit with physical quark masses. Results are derived from\ncorrelation functions computed on MILC collaboration gauge configurations with\nthree different lattice spacings and including 2+1+1 flavours of sea quarks in\nthe Highly Improved Staggered Quark (HISQ) formalism. HISQ is also used for all\nof the valence quarks. The uncertainty on the decay widths from our form\nfactors for $B_c^+ \\to D^0 \\ell^+ \\nu_{\\ell}$ is similar in size to that from\nthe present value for $V_{ub}$. We obtain the ratio $\\Gamma (B_{c}^{+}\n\\rightarrow D^0 \\mu^{+} \\nu_{\\mu}) /\\left|\\eta_{\\mathrm{EW}} V_{u\nb}\\right|^{2}=4.43(63) \\times 10^{12} \\mathrm{~s}^{-1}$. Combining our form\nfactors with those found previously by HPQCD for $B_{c}^{+} \\rightarrow J /\n\\psi \\mu^{+} \\nu_{\\mu}$, we find $\\left|V_{cb}/V_{ub} \\right|^2 \\Gamma( B_c^+\n\\to D^0 \\mu^+ \\nu_\\mu )/\\Gamma(B_{c}^{+} \\rightarrow J / \\psi \\mu^{+}\n\\nu_{\\mu}) = 0.257(36)_{B_c \\to D}(18)_{B_c \\to J/\\psi}$. We calculate the\ndifferential decay widths of $B_c^+ \\to D_s^+ \\ell^+ \\ell^-$ across the full\n$q^2$ range, and give integrated results in $q^2$ bins that avoid possible\neffects from charmonium and $u \\overline{u}$ resonances. For example, we find\nthat the ratio of differential branching fractions integrated over the range\n$q^2 = 1 \\; \\mathrm{GeV}^2 - 6 \\; \\mathrm{GeV}^2$ for $B_c^+ \\to D_s^+ \\mu^+\n\\mu^-$ and $B_{c}^{+} \\rightarrow J / \\psi \\mu^{+} \\nu_{\\mu}$ is $6.31{\\tiny\n}(90)_{B_c \\to D_s}(65)_{B_c \\to J/\\psi} \\times 10^{-6}$. We also give results\nfor the branching fraction of $B_c^+ \\to D_s^+ \\nu \\overline{\\nu}$."
    },
    {
        "anchor": "Monopoles and deconfinement transition in finite temperature $SU(2)$ QCD: We investigate the role of monopoles in the deconfinement transition of\nfinite temperature $SU(2)$ QCD in the maximally abelian gauge. In the\nconfinement phase a long monopole loop exists in each configuration, whereas no\nlong loop exists in the deep deconfinement region. Balancing of the energy and\nthe entropy of loops of the maximally extended monopoles can explain the\noccurrence of the deconfinement transition.",
        "positive": "Performance Tests of the Kramers Equation and Boson Algorithms for\n  Simulations of QCD: We present a performance comparison of the Kramers equation and the boson\nalgorithms for simulations of QCD with two flavors of dynamical Wilson fermions\nand gauge group $SU(2)$. Results are obtained on $6^312$, $8^312$ and $16^4$\nlattices. In both algorithms a number of optimizations are installed."
    },
    {
        "anchor": "Large N transition in the 2D SU(N)xSU(N) nonlinear sigma model: We consider the characteristic polynomial associated with the smoothed two\npoint function in two dimensional large N principal chiral model. We\nnumerically show that it undergoes a transition at a critical distance of the\norder of the correlation length. The transition is in the same universality\nclass as two dimensional large N QCD.",
        "positive": "Comparing Tensor Renormalization Group and Monte Carlo calculations for\n  spin and gauge models: We show that the Tensor Renormalization Group (TRG) method can be applied to\nO(N) spin models, principal chiral models and pure gauge theories (Z2, U(1) and\nSU(2)) on (hyper) cubic lattices. We explain that contrarily to some common\nbelief, it is very difficult to write compact formulas expressing the\nblockspinning of lattice models. We show that in contrast to other approaches,\nthe TRG formulation allows us to write exact blocking formulas with numerically\ncontrollable truncations. The basic reason is that the TRG blocking separates\nneatly the degrees of freedom inside the block and which are integrated over,\nfrom those kept to communicate with the neighboring blocks. We argue that the\nTRG is a method that can handle large volumes, which is crucial to approach\nquasi-conformal systems. The method can also get rid of some sign problems. We\ndiscuss recent results regarding the critical properties of the 2D O(2)\nnonlinear sigma model with complex beta and chemical potential. As some of\nthese results appeared in a recently published paper (PRD 88, 056005) and two\nrecent preprints (arXiv:1309.4963 and arXiv:1309.6623), these proceedings\nrather emphasize the conceptual aspects of our ongoing effort."
    },
    {
        "anchor": "$B \\rightarrow D l \u03bd$ Form Factors at Non-Zero Recoil and Extraction\n  of $|V_{cb}|$: We present a lattice QCD calculation of the $B \\rightarrow D l \\nu$\nsemileptonic decay form factors $f_+(q^2)$ and $f_0(q^2)$ for the entire\nphysical $q^2$ range. Non-relativistic QCD (NRQCD) bottom quarks and Highly\nImproved Staggered Quark (HISQ) charm and light quarks are employed together\nwith $N_f = 2+1$ MILC gauge configurations. A joint fit to our lattice and\nBaBar experimental data allows an extraction of the CKM matrix element\n$|V_{cb}|$. We also determine the phenomenologically interesting ratio $R(D) =\n{\\cal B}(B \\rightarrow D \\tau \\nu_\\tau) / {\\cal B}(B \\rightarrow D l \\nu_l)$\n($l = e, \\mu$). We find $|V_{cb}|_{excl.}^{B \\rightarrow D} = 0.0402(17)(13)$,\nwhere the first error consists of the lattice simulation errors and the\nexperimental statistical error and the second error is the experimental\nsystematic error. For the branching fraction ratio we find $R(D) = 0.300(8)$.",
        "positive": "Coulomb gauge studies of SU(3) Yang-Mills theory on the lattice: We study the infrared behaviour of lattice SU(3) Yang-Mills theory in Coulomb\ngauge in terms of the ghost propagator, the Coulomb potential and the\ntransversal and the time-time component of the equal-time gluon propagator. In\nparticular, we focus on the Gribov problem and its impact on the observables.\nWe observe that the simulated annealing method is advantageous for fixing the\nCoulomb gauge in large volumes. We study finite size and discretization\neffects. While finite size effects can be controlled by the cone cut, and the\nghost propagator and the Coulomb potential become scaling functions with the\ncylinder cut, the equal-time gluon propagator does not show scaling in the\nconsidered range of the inverse coupling constant. The ghost propagator is\ninfrared enhanced. The Coulomb potential is now extended to considerably lower\nmomenta and shows a more complicated infrared regime. The Coulomb string\ntension satisfies Zwanziger's inequality, but its estimate can be considered\nonly preliminary because of the systematic Gribov effect that is particularly\nstrong for the Coulomb potential."
    },
    {
        "anchor": "Coulomb gauge Gribov copies and the confining potential: We study the approach, initiated by Marinari et al., to the static\ninter-quark potential based on Polyakov lines of finite temporal extent,\nevaluated in Coulomb gauge. We show that, at small spatial separations, the\npotential can be understood as being between two separately gauge invariant\ncolour charges. At larger separations Gribov copies obstruct the\nnon-perturbative identification of individually gauge invariant colour states.\nWe demonstrate, for the first time, how gauge invariance can be maintained\nquite generally by averaging over Gribov copies. This allows us to extend the\nanalysis of the Polyakov lines and the corresponding, gauge invariant\nquark-antiquark state to all distance scales. Using large scale lattice\nsimulations, we show that this interpolating state possesses a good overlap\nwith the ground state in the quark-antiquark sector and yields the full static\ninter-quark potential at all distances. A visual representation of the Gribov\ncopies on the lattice is also presented.",
        "positive": "In Search of the Chiral Regime: A critical appraisal is given of a recent analysis of the quark-mass and\nfinite-size dependence of unquenched lattice QCD data for the nucleon mass. We\nuse this forum to estimate the boundary of the chiral regime for nucleon\nproperties."
    },
    {
        "anchor": "A new scheme for the running coupling constant in gauge theories using\n  Wilson loops: We propose a new renormalization scheme of the running coupling constant in\ngeneral gauge theories using the Wilson loops. The renormalized coupling\nconstant is obtained from the Creutz ratio in lattice simulations and the\ncorresponding perturbative coefficient at the leading order. The latter can be\ncalculated by adopting the zeta-function resummation techniques. We perform a\nbenchmark test of our scheme in quenched QCD with the plaquette gauge action.\nThe running of the coupling constant is determined by applying the step-scaling\nprocedure. Using several methods to improve the statistical accuracy, we show\nthat the running coupling constant can be determined in a wide range of energy\nscales with relatively small number of gauge configurations.",
        "positive": "Kramers-Wannier duality and worldline representation for the SU(2)\n  principal chiral model: In this letter we explore different representations of the SU(2) principal\nchiral model on the lattice. We couple chemical potentials to two of the\nconserved charges to induce finite density. This leads to a complex action such\nthat the conventional field representation cannot be used for a Monte Carlo\nsimulation. Using the recently developed Abelian color flux approach we derive\na new worldline representation where the partition sum has only real and\npositive weights, such that a Monte Carlo simulation is possible. In a second\nstep we transform the model to new dual variables in the Kramers-Wannier (KW)\nsense, such that the constraints are automatically fulfilled, and we obtain a\nsecond representation free of the complex action problem. We implement\nexploratory Monte Carlo simulations for both, the worldline, as well as the\nKW-dual form, for cross-checking the two dualizations and a first assessment of\ntheir potential for dual simulations."
    },
    {
        "anchor": "Electroweak Phase Transition and Numerical Simulations in the SU(2)\n  Higgs Model: Recent progress in non-perturbative investigations of the electroweak phase\ntransition is reviewed, with special emphasis on numerical simulations in the\nfour-dimen\\-sional SU(2) Higgs model.",
        "positive": "The search for new physics in $B \\to K \\ell^+\\ell^-$ and $B \\to K\n  \u03bd\\bar\u03bd$ using precise lattice QCD form factors: We present HPQCD's improved scalar, vector and tensor form factors for $B \\to\nK$ semileptonic decays, using the heavy-HISQ formalism for more accurate\nnormalisation of the weak currents. Working with masses close to the physical\n$b$ on the finest ensemble and including three ensembles with physical light\nquarks, we cover the full physical $q^2$ range with good precision. Our\nuncertainties at $q^2=0$ are a factor of three better than earlier work.\n  We compare Standard Model observables using our form factors to experimental\nmeasurements for the rare flavour changing neutral current processes $B \\to K\n\\ell^+\\ell^-$ and $B \\to K \\nu\\bar{\\nu}$ and discuss the significance of the\ntensions that arise."
    },
    {
        "anchor": "Some Insights into the Method of Center Projection: We present several new results which pertain to the successes of center\nprojection in maximal center gauge (MCG). In particular, we show why any center\nvortex, inserted \"by hand\" into a thermalized lattice configuration, will be\namong the set of vortices found by the center projection procedure. We show\nthat this \"vortex-finding property\" is lost when gauge-field configurations are\nfixed to Landau gauge prior to the maximal center gauge fixing; this fact\naccounts for the loss of center dominance in the corresponding projected\nconfigurations. Variants of maximal center (adjoint Landau) gauge are proposed\nwhich correctly identify relevant center vortices.",
        "positive": "Fermion Doubling and Gauge Invariance on Random Lattices: Random-lattice fermions have been shown to be free of the doubling problem if\nthere are no interactions or interactions of a non-gauge nature. On the other\nhand, gauge interactions impose stringent constraints as expressed by the\nWard-Takahashi identities which could revive the free-field suppressed doubler\nmodes in loop diagrams. Comparing random lattice, naive and Wilson fermions in\ntwo dimensional abelian background gauge theory, we show that indeed the\ndoublers are revived for random lattices in the continuum limit. Some\nimplications of the persistent doubling phenomenon on random lattices are also\ndiscussed."
    },
    {
        "anchor": "Unquenching the Landau Gauge Lattice Propagators and the Gribov Problem: The gluon and ghost propagators are computed using both quenched and\ndynamical configurations for the same lattice spacings. The Wilson fermions are\nsimulated at several quark masses. Furthermore, the effect of the Gribov copies\nis evaluated for all sets of configurations.",
        "positive": "Nucleon structure functions with domain wall fermions: We present a quenched lattice QCD calculation of the first few moments of the\npolarized and un-polarized structure functions of the nucleon. Our calculations\nare done using domain wall fermions and the DBW2 gauge action with inverse\nlattice spacing ~1.3GeV, physical volume approximatelly (2.4 fm)^3, and light\nquark masses down to about 1/4 the strange quark mass. Values of the individual\nmoments are found to be significantly larger than experiment, as in past\nlattice calculations, but interestingly the chiral symmetry of domain wall\nfermions allows for a precise determination of the ratio of the flavor\nnon-singlet momentum fraction to the helicity distribution, which is in very\ngood agreement with experiment. We discuss the implications of this result.\nNext, we show that the chiral symmetry of domain wall fermions is useful in\neliminating mixing of power divergent lower dimensional operators with twist-3\noperators. Finally, we find the isovector tensor charge at renormalization\nscale 2 GeV in the MS bar scheme to be 1.192(30), where the error is the\nstatistical error only."
    },
    {
        "anchor": "Hadron Structure on the Lattice: A few chosen nucleon properties are described from a lattice QCD perspective:\nthe nucleon sigma term and the scalar strangeness in the nucleon; the vector\nform factors in the nucleon, including the vector strangeness contribution, as\nwell as parity breaking effects like the anapole and electric dipole moment;\nand finally the axial and tensor charges of the nucleon. The status of the\nlattice calculations is presented and their potential impact on phenomenology\nis discussed.",
        "positive": "Update on $f_B$: We describe the current status of the MILC collaboration computation of\n$f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$ and their ratios. Progress over the past\nyear includes: better statistics and plateaus at $\\beta=6.52$ (quenched),\n$\\beta=5.6$ ($N_F=2$) and $\\beta=5.445$ ($N_F=2$), new runs with a wide range\nof dynamical quark masses at $\\beta=5.5$ ($N_F=2$), an estimate of the\nsystematic errors due to the chiral extrapolation, and an improved analysis\nwhich consistently takes into account both the correlations in the data at\nevery stage and the systematic effects due to changing fitting ranges."
    },
    {
        "anchor": "Virtual Photon Emission in Leptonic Decays of Pseudoscalar Mesons: We present a preliminary non-perturbative lattice calculation of the form\nfactors entering the processes $K\\to \\ell\\,\\nu_\\ell\\,\\ell'^+\\,\\ell'^-$ and of\nthe corresponding branching ratios. These form factors describe the interaction\nbetween the mediating virtual photon and the internal hadronic structure of the\nmeson. By separating them from the point-like contribution to the matrix\nelement we are able to isolate and reconstruct the structure-dependent\ncontribution to the decay width. Our numerical analysis employs only one gauge\nensemble and so it is affected by systematic uncertainties due to the missing\ncontinuum and physical point extrapolation. Despite this, we already find a\nreasonable agreement with the experimental data and with the next to leading\norder Chiral Perturbation Theory predictions. The method is general and can be\napplied to any pseudoscalar meson, though for heavier mesons the possibility of\ninternal lighter states becomes problematic and still needs a proper study. A\nnon-perturbative, model-independent lattice evaluation of these processes would\nallow further progress in the theoretical predictions of SM hadronic quantities\nand in the search of New Physics.",
        "positive": "Unitarity of the infinite-volume three-particle scattering amplitude\n  arising from a finite-volume formalism: In a previous publication, two of us derived a relation between the\nscattering amplitude of three identical bosons, $\\mathcal M_3$, and a real\nfunction referred to as the {divergence-free} K matrix and denoted $\\mathcal\nK_{\\text{df},3}$. The result arose in the context of a relation between\nfinite-volume energies and $\\mathcal K_{\\text{df},3}$, derived to all orders in\nthe perturbative expansion of a generic low-energy effective field theory. In\nthis work we set aside the role of the finite volume and focus on the\ninfinite-volume relation between $\\mathcal K_{\\text{df},3}$ and $\\mathcal M_3$.\nWe show that, for any real choice of $\\mathcal K_{\\text{df},3}$, $\\mathcal M_3$\nsatisfies the three-particle unitarity constraint to all orders. Given that\n$\\mathcal K_{\\text{df},3}$ is also free of a class of kinematic divergences,\nthe function may provide a useful tool for parametrizing three-body scattering\ndata. Applications include the phenomenological analysis of experimental data\n(where the connection to the finite volume is irrelevant) as well as\ncalculations in lattice quantum chromodynamics (where the volume plays a key\nrole)."
    },
    {
        "anchor": "Studying and removing effects of fixed topology in a quantum mechanical\n  model: At small lattice spacing, or when using e.g. overlap fermions, lattice QCD\nsimulations tend to become stuck in a single topological sector. Physical\nobservables then differ from their full QCD counterparts by 1/V corrections,\nwhere V is the spacetime volume. Brower et al. and Aoki et al. have derived\nequations by means of a saddle point approximation, to determine and to remove\nthese corrections. We extend these equations and apply them to a simple toy\nmodel, a quantum mechanical particle on a circle in a square well potential at\nfixed topology. This model can be solved numerically up to arbitrary precision\nand allows to explore effects arising due to fixed topology. We investigate the\nrange of validity and accuracy of the above mentioned equations, to remove such\nfixed topology effects.",
        "positive": "A Lattice Study of $(\\bar{D}_1 D^{*})^\\pm$ Near-threshold Scattering: In this exploratory lattice study, low-energy near threshold scattering of\nthe $(\\bar{D}_1 D^{*})^\\pm$ meson system is analyzed using lattice QCD with\n$N_f=2$ twisted mass fermion configurations. Both s-wave ($J^P=0^-$) and p-wave\n($J^P=1^+$) channels are investigated. It is found that the interaction between\nthe two charmed mesons is attractive near the threshold in both channels. This\ncalculation provides some hints in the searching of resonances or bound states\naround the threshold of $(\\bar{D}_1 D^{*})^\\pm$ system."
    },
    {
        "anchor": "Testing volume independence of large N gauge theories on the lattice: For a pure SU(N) gauge theory on the lattice we test if the expectation\nvalues of small Wilson loops become volume independent in the large N limit.",
        "positive": "Towards robust constraints on nuclear effective field theory from\n  lattice QCD: We will discuss several new results from the NPLQCD Collaboration that\ncombine lattice QCD results on (hyper)nuclear systems at unphysical pion masses\ntogether with nuclear effective field theories. Two-baryon channels with\nstrangeness $0$ to $-4$ are analyzed, with findings that point to interesting\nsymmetries observed in hypernuclear forces as predicted in the limit of QCD\nwith a large number of colors. Also, several matrix elements of light nuclei\nare studied. The tritium axial charge, related to the Gamow-Teller matrix\nelement, and the longitudinal momentum fraction of $^3$He that is carried by\nthe isovector combination of $u$ and $d$ are extracted and extrapolated to the\nphysical point. For this latter case, it can be seen how including lattice\nresults to experimental determinations can have imminent potential to enable\nmore precise determinations and to reveal the QCD origins of the EMC effect."
    },
    {
        "anchor": "Instantons and monopoles in lattice QCD: We analyze the interplay of topological objects in four-dimensional QCD on\nthe lattice. The distributions of color magnetic monopoles in the maximum\nabelian gauge are computed around instantons in both pure and full QCD. We find\nan enhanced probability for monopoles inside the core of an instanton on gauge\nfield average. This feature is independent of the topological charge definition\nused. For specific gauge field configurations we visualize the situation\ngraphically. Moreover we investigate how monopole loops and instantons are\ncorrelated with the chiral condensate. Strong evidence is found that clusters\nof the quark condensate and topological objects coexist locally on individual\nconfigurations.",
        "positive": "Nucleon Sigma Terms with $N_f = 2 + 1$ O($a$)-improved Wilson fermions: We present a lattice-QCD based analysis of the nucleon sigma terms using\ngauge ensembles with $N_f = 2 + 1$ flavors of ${\\cal O}(a)$-improved Wilson\nfermions, with a complete error budget concerning excited-state contaminations,\nthe chiral interpolation as well as finite-size and lattice spacing effects. We\ncompute the sigma terms determined directly from the matrix elements of the\nscalar currents. The chiral interpolation is based on SU(3) baryon chiral\nperturbation theory using the extended on-mass shell renormalization scheme.\nFor the pion nucleon sigma term, we obtain $\\sigma_{\\pi N} = (43.7\\pm3.6)$ MeV,\nwhere the error includes our estimate of the aforementioned systematics. The\ntension with extractions based on dispersion theory persists at the\n2.4-$\\sigma$ level. For the strange sigma term, we obtain a non-zero value,\n$\\sigma_s=(28.6\\pm9.3)$ MeV."
    },
    {
        "anchor": "Broken Symmetries from Minimally Doubled Fermions: Novel chirally symmetric fermion actions containing the minimum amount of\nfermion doubling have been recently proposed in the literature. We study the\nsymmetries and renormalization of these actions and find that in each case,\ndiscrete symmetries, such as parity and time-reversal, are explicitly broken.\nConsequently, when the gauge interactions are included, these theories\nradiatively generate relevant and marginal operators. Thus the restoration of\nthese symmetries and the approach to the continuum limit require the\nfine-tuning of several parameters. With some assumptions, we show that this\nbehavior is unavoidable for actions displaying minimal fermion doubling.",
        "positive": "Gauge Fixing on the Lattice without Ambiguity: A new gauge fixing condition is discussed, which is (lattice) rotation\ninvariant, has the `smoothness' properties of the Landau gauge but can be\nefficiently computed and is unambiguous for almost all lattice gauge field\nconfigurations."
    },
    {
        "anchor": "The Schwinger Model with Perfect Staggered Fermions: We construct a new perfect action for free staggered fermions, which is more\nlocal than the one obtained from the standard block average scheme. This pays\noff in superior properties after a short ranged truncation. This action is\n``gauged by hand'' and tested in Schwinger model simulations by means of a new\nvariant of hybrid MC. Using ``fat links'' for the gauge field, we obtain a tiny\n``pion'' mass down to \\beta \\approx 1.5, and the ``eta'' mass follows very\nclosely the prediction of asymptotic scaling.",
        "positive": "Lattice field computations via recursive numerical integration: We investigate the application of efficient recursive numerical integration\nstrategies to models in lattice gauge theory from quantum field theory. Given\nthe coupling structure of the physics problems and the group structure within\nlattice cubature rules for numerical integration, we show how to approach these\nproblems efficiently by means of Fast Fourier Transform techniques. In\nparticular, we consider applications to the quantum mechanical rotor and\ncompact U(1) lattice gauge theory, where the physical dimensions are two and\nthree. This proceedings article reviews our results presented in J. Comput.\nPhys 443 (2021) 110527."
    },
    {
        "anchor": "Lattice QCD results on cumulant ratios at freeze-out: Ratios of cumulants of net proton-number fluctuations measured by the STAR\nCollaboration show strong deviations from a skellam distribution, which should\ndescribe thermal properties of cumulant ratios, if proton-number fluctuations\nare generated in equilibrium and a hadron resonance gas (HRG) model would\nprovide a suitable description of thermodynamics at the freeze-out temperature.\nWe present some results on sixth order cumulants entering the calculation of\nthe QCD equation of state at non-zero values of the baryon chemical potential\n(mu_B) and discuss limitations on the applicability of HRG thermodynamics\ndeduced from a comparison between QCD and HRG model calculations of cumulants\nof conserved charge fluctuations. We show that basic features of the\n$\\mu_B$-dependence of skewness and kurtosis ratios of net proton-number\nfluctuations measured by the STAR Collaboration resemble those expected from a\nO(mu_B^2) QCD calculation of the corresponding net baryon-number cumulant\nratios.",
        "positive": "Pion decay in magnetic fields: The leptonic decay of the charged pion in the presence of background magnetic\nfields is investigated using quenched Wilson fermions. It is demonstrated that\nthe magnetic field opens up a new channel for this decay. The magnetic\nfield-dependence of the decay constants for both the ordinary and the new\nchannel is determined. Using these inputs from QCD, we calculate the total\ndecay rate perturbatively."
    },
    {
        "anchor": "An Extraction of Vcb from the Semi-Leptonic B->D* Decay: We present an extraction of Vcb from a lattice calculation of the B->D* decay\nmatrix elements. We obtain |Vcb| \\sqrt{ \\frac{ \\tauB }{ 1.49 ps } } = 0.037^{+3\n\\ +5}_{-3 \\ -5} from a single parameter fit to the new CLEO data. Email\nnmh@uk.ac.ed.ph.th",
        "positive": "Nonperturbative Studies of Quantum Gravity: We investigate quantum gravity in the path integral formulation using the\nRegge calculus. Restricting the quadratic link lengths of the originally\ntriangular lattice the path integral can be transformed to the partition\nfunction of a spin system with higher couplings on a Kagome lattice. Various\nmeasures acting as external field were considered. Extensions to matter fields\nand higher dimensions are discussed."
    },
    {
        "anchor": "Electromagnetic Polarizabilities: Lattice QCD in Background Fields: Chiral perturbation theory makes definitive predictions for the extrinsic\nbehavior of hadrons in external electric and magnetic fields. Near the chiral\nlimit, the electric and magnetic polarizabilities of pions, kaons, and nucleons\nare determined in terms of a few well-known parameters. In this limit, hadrons\nbecome quantum mechanically diffuse as polarizabilities scale with the inverse\nsquare-root of the quark mass. In some cases, however, such predictions from\nchiral perturbation theory have not compared well with experimental data.\nUltimately we must turn to first principles numerical simulations of QCD to\ndetermine properties of hadrons, and confront the predictions of chiral\nperturbation theory. To address the electromagnetic polarizabilities, we\nutilize the background field technique. Restricting our attention to\ncalculations in background electric fields, we demonstrate new techniques to\ndetermine electric polarizabilities and baryon magnetic moments for both\ncharged and neutral states. As we can study the quark mass dependence of\nobservables with lattice QCD, the lattice will provide a crucial test of our\nunderstanding of low-energy QCD, which will be timely in light of ongoing\nexperiments, such as at COMPASS and HI\\gamma S.",
        "positive": "Fermionic quantum field theories as probabilistic cellular automata: A class of fermionic quantum field theories with interactions is shown to be\nequivalent to probabilistic cellular automata, namely cellular automata with a\nprobability distribution for the initial states. Probabilistic cellular\nautomata on a one-dimensional lattice are equivalent to two - dimensional\nquantum field theories for fermions. They can be viewed as generalized Ising\nmodels on a square lattice and therefore as classical statistical systems. As\nquantum field theories they are quantum systems. Thus quantum mechanics emerges\nfrom classical statistics. As an explicit example for an interacting fermionic\nquantum field theory we describe a type of discretized Thirring model as a\ncellular automaton. The updating rule of the automaton is encoded in the step\nevolution operator that can be expressed in terms of fermionic annihilation and\ncreation operators. The complex structure of quantum mechanics is associated to\nparticle -- hole transformations. The naive continuum limit exhibits Lorentz\nsymmetry. We exploit the equivalence to quantum field theory in order to show\nhow quantum concepts as wave functions, density matrix, non-commuting operators\nfor observables and similarity transformations are convenient and useful\nconcepts for the description of probabilistic cellular automata."
    },
    {
        "anchor": "Majorana fermions on the lattice: The Monte Carlo simulation of Majorana fermions is discussed on the example\nof supersymmetric Yang-Mills (SYM) theory.",
        "positive": "Magnetic Moments of Negative-Parity Baryons from Lattice QCD: We report preliminary results for the magnetic moments of negative-parity\nbaryons extracted from mass shifts in the presence of static external magnetic\nfields. The calculations are done on $24^3\\times 48$ quenched lattices using\nstandard Wilson actions, with $\\beta$=6.0 and pion mass down to about 520 MeV,\nand 1000 configurations. Reasonable signals for the negative-parity states are\nobserved and the sign of their magnetic moments is established. The results are\ncompared to model calculations."
    },
    {
        "anchor": "The confining string and its breaking in QCD: We point out that the world sheet swept by the confining string in presence\nof dynamical quarks can belong to two different phases, depending on the number\nof charge species and the quark masses. When it lies in the normal phase (as\nopposed to the tearing one) the string breaking is invisible in the Wilson\nloop, while is manifest in operators composed of disjoint sources, as observed\nin many numerical experiments. We work out an explicit formula for the\ncorrelator of Polyakov loops at finite temperature, which is then compared with\nrecent lattice data, both in the quenched case and in presence of dynamical\nquarks. The analysis in the quenched case shows that the free bosonic string\nmodel describes accurately the data for distances larger than ~ 0.75 fm. In the\nunquenched case we derive predictions on the dependence of the static potential\non the temperature which are compatible with the lattice data.",
        "positive": "Primitive Quantum Gates for an $SU(2)$ Discrete Subgroup: Binary\n  Octahedral: We construct a primitive gate set for the digital quantum simulation of the\n48-element binary octahedral ($\\mathbb{BO}$) group. This nonabelian discrete\ngroup better approximates $SU(2)$ lattice gauge theory than previous work on\nthe binary tetrahedral group at the cost of one additional qubit -- for a total\nof six -- per gauge link. The necessary primitives are the inversion gate, the\ngroup multiplication gate, the trace gate, and the $\\mathbb{BO}$ Fourier\ntransform."
    },
    {
        "anchor": "Evidence for hard chiral logarithms in quenched lattice QCD: We present the first direct evidence that quenched QCD differs from full QCD\nin the chiral ($m_q \\rightarrow 0$) limit, as predicted by chiral perturbation\ntheory, from our quenched lattice QCD simulations at $\\beta = 6/g^2 = 6.0$. We\nmeasured the spectrum of light hadrons on $16^3 \\times 64$, $24^3 \\times 64$\nand $32^3 \\times 64$, using staggered quarks of masses $m_q=0.01$, $m_q=0.005$\nand $m_q=0.0025$. The pion masses showed clear evidence for logarithmic\nviolations of the PCAC relation $m_{\\pi}^2 \\propto m_q$, as predicted by\nquenched chiral perturbation theory. The dependence on spatial lattice volume\nprecludes this being a finite size effect. No evidence was seen for such chiral\nlogarithms in the behaviour of the chiral condensate\n$\\langle\\bar{\\psi}\\psi\\rangle$.",
        "positive": "Monopole Condensation in Gauge Theory Vacuum: The condensation of monopoles (dual superconductivity) of QCD vacuum is\nreviewed. Direct evidence is produced that the system, in the confined phase,\nis a dual superconductor."
    },
    {
        "anchor": "Lattice QCD at non-zero temperature and baryon density: Lectures given at the Summer School on \"Modern perspectives in lattice QCD\",\nLes Houches, August 3-28, 2009",
        "positive": "Scalar mesons moving in a finite volume and the role of partial wave\n  mixing: Phase shifts and resonance parameters can be obtained from finite-volume\nlattice spectra for interacting pairs of particles, moving with nonzero total\nmomentum. We present a simple derivation of the method that is subsequently\napplied to obtain the pi pi and pi K phase shifts in the sectors with total\nisospin I=0 and I=1/2, respectively. Considering different total momenta, one\nobtains extra data points for a given volume that allow for a very efficient\nextraction of the resonance parameters in the infinite-volume limit.\nCorrections due to the mixing of partial waves are provided. We expect that our\nresults will help to optimize the strategies in lattice simulations, which aim\nat an accurate determination of the scattering and resonance properties."
    },
    {
        "anchor": "An example of optimal field cut in lattice gauge perturbation theory: We discuss the weak coupling expansion of a one plaquette SU(2) lattice gauge\ntheory. We show that the conventional perturbative series for the partition\nfunction has a zero radius of convergence and is asymptotic. The average\nplaquette is discontinuous at g^2=0. However, the fact that SU(2) is compact\nprovides a perturbative sum that converges toward the correct answer for\npositive g^2. This alternate methods amounts to introducing a specific coupling\ndependent field cut, that turns the coefficients into g-dependent quantities.\nGeneralizing to an arbitrary field cut, we obtain a regular power series with a\nfinite radius of convergence. At any order in the modified perturbative\nprocedure, and for a given coupling, it is possible to find at least one (and\nsometimes two) values of the field cut that provide the exact answer. This\noptimal field cut can be determined approximately using the strong coupling\nexpansion. This allows us to interpolate accurately between the weak and strong\ncoupling regions. We discuss the extension of the method to lattice gauge\ntheory on a D-dimensional cubic lattice.",
        "positive": "Rho meson decay width in SU(2) gauge theories with 2 fundamental\n  flavours: SU(2) gauge theories with two quark flavours in the fundamental\nrepresentation are among the most promising theories of composite dynamics\ndescribing the electroweak sector. Three out of five Goldstone bosons in these\nmodels become the longitudinal components of the W and Z bosons giving them\nmass. Like in QCD, we expect a spectrum of excitations which appear as\nresonances in vector boson scattering, in particular the vector resonance\ncorresponding to the rho-meson in QCD. In this talk I will present the\npreliminary results of the first calculation of the rho-meson decay width in\nthis theory, which is analogous to rho to two pions decay calculation in QCD.\nThe results presented were calculated in a moving frame with total momentum\n(0,0,1) on two ensembles. Future plans include using 3 moving frames on a\nlarger set of ensembles to extract the resonance parameters more reliably and\nalso take the chiral and continuum limits."
    },
    {
        "anchor": "Ginsparg-Wilson operators and a no-go theorem: If one uses a general class of Ginsparg-Wilson operators, it is known that CP\nsymmetry is spoiled in chiral gauge theory for a finite lattice spacing and the\nMajorana fermion is not defined in the presence of chiral symmetric Yukawa\ncouplings. We summarize these properties in the form of a theorem for the\ngeneral Ginsparg-Wilson relation.",
        "positive": "Chiral condensate from the spectrum of the staggered Dirac operator: The chiral condensate is computed from the mode number of the staggered Dirac\noperator. This result is compared with those obtained with other approaches,\nbased on the quark mass dependence of the topological susceptibility and of the\npion mass."
    },
    {
        "anchor": "On the possibility of the critical behavior of LGT in the area of\n  asymptotically large \u03b2: Coupling dependence on lattice spacing and size is estimated analytically at\n\\beta -> \\infty region where for a->0 the critical area is shifted in\naccordance with Callan-Symanzik relation. In considered approximation no trace\nof critical behavior is found in this area.",
        "positive": "Alternating Descent Method for Gauge Cooling of Complex Langevin\n  Simulations: We study the gauge cooling technique for the complex Langevin method applied\nto the computation in lattice quantum chromodynamics. We propose a new solver\nof the minimization problem that optimizes the gauge, which does not include\nany parameter in each iteration, and shows better performance than the\nclassical gradient descent method especially when the lattice size is large.\nTwo numerical tests are carried out to show the effectiveness of the new\nalgorithm."
    },
    {
        "anchor": "Heavy quark physics from lattice QCD: I review the current status of lattice calculations of heavy quark\nquantities. Particular emphasis is placed on leptonic and semileptonic decay\nmatrix elements.",
        "positive": "Taylor expansions and Pad\u00e9 approximations for Lefschetz thimbles and\n  beyond: Deforming the domain of integration after complexification of the field\nvariables is an intriguing idea to tackle the sign problem. In thimble\nregularization the domain of integration is deformed into an union of manifolds\ncalled Lefschetz thimbles. On each thimble the imaginary part of the action\nstays constant and the sign problem disappears. A long standing issue of this\napproach is how to determine the relative weight to assign to each thimble\ncontribution in the (multi)-thimble decomposition. Yet this is an issue one has\nto face, as previous work has shown that different theories exist for which the\ncontributions coming from thimbles other than the dominant one cannot be\nneglected. Historically, one of the first examples of such theories is the\none-dimensional Thirring model. Here we discuss how Taylor expansions can be\nused to by-pass the need for multi-thimble simulations. If multiple, disjoint\nregions can be found in the parameters space of the theory where only one\nthimble gives a relevant contribution, multiple Taylor expansions can be\ncarried out in those regions to reach other regions by single thimble\nsimulations. Better yet, these Taylor expansions can be bridged by Pad\\'e\ninterpolants. Not only does this improve the convergence properties of the\nseries, but it also gives access to information about the analytical structure\nof the observables. The true singularities of the observables can be recovered.\nWe show that this program can be applied to the one-dimensional Thirring model\nand to a (simple) version of HDQCD. But the general idea behind our strategy\ncan be helpful beyond thimble regularization itself, i.e. it could be valuable\nin studying the singularities of QCD in the complex $\\mu_B$ plane. Indeed this\nis a program that is currently being carried out by the Bielefeld-Parma\ncollaboration."
    },
    {
        "anchor": "The lattice Landau gauge photon propagator for 4D compact QED: In this work we report on the Landau gauge photon propagator computed for\npure gauge 4D compact QED in the confined and deconfined phases and for large\nlattices volumes: $32^4$, $48^4$ and $96^4$. In the confined phase, compact QED\ndevelops mass scales that render the propagator finite at all momentum scales\nand no volume dependence is observed for the simulations performed.\nFurthermore, for the confined phase the propagator is compatible with a Yukawa\nmassive type functional form. For the deconfined phase the photon propagator\nseems to approach a free field propagator as the lattice volume is increased.\nIn both cases, we also investigate the static potential and the average value\nof the number of Dirac strings in the gauge configurations $m$. In the confined\nphase the mass gap translates into a linearly growing static potential, while\nin the deconfined phase the static potential approaches a constant at large\nseparations. Results shows that $m$ is, at least, one order of magnitude larger\nin the confined phase and confirm that the appearance of a confined phase is\nconnected with the topology of the gauge group.",
        "positive": "Finite temperature QCD with $N_f=2+1+1$ Wilson twisted mass fermions at\n  physical pion, strange and charm masses: We discuss recent progress in studying Quantum Chromodynamics at finite\ntemperature using $N_f=2+1+1$ Wilson twisted mass fermions. Particular interest\nis in QCD symmetries and their breaking and restoration. First, we discuss the\nbehaviour of the $\\eta'$ meson at finite temperature, which is tightly\nconnected to the axial and chiral symmetries. The results suggest a small\ndecrease of the $\\eta'$ mass in the pseudo-critical region coming close to the\nnon-anomalous contribution and subsequent growth at large temperatures. Second,\nwe present the first results of lattice simulations of Quantum Chromodynamics\nwith $N_f=2+1+1$ twisted mass Wilson fermions at physical pion, strange and\ncharm masses. We estimate the chiral pseudo-critical temperatures for different\nobservables. Our preliminary results are consistent with a second order\ntransition in the chiral limit, however other scenarios are not excluded."
    },
    {
        "anchor": "Can the complex Langevin method see the deconfinement phase transition\n  in QCD at finite density?: Exploring the phase diagram of QCD at finite density is a challenging problem\nsince first-principle calculations based on standard Monte Carlo methods suffer\nfrom the sign problem. As a promising approach to this issue, the complex\nLangevin method (CLM) has been pursued intensively.In this work, we investigate\nthe applicability of the CLM in the vicinity of the deconfinement phase\ntransition using the four-flavor staggered fermions. In particular, we look for\na signal of the expected first order phase transition within the validity\nregion of the CLM.",
        "positive": "Temperature dependence of instantons in QCD: We investigate the temperature dependence of the instanton contents of gluon\nfields, using unquenched lattice QCD and the cooling method. The instanton size\nparameter deduced from the correlation function decreases from 0.44fm below the\nphase-transition temperature $T_c$ ($\\approx 150$MeV) to 0.33fm at 1.3 $T_c$.\nThe instanton charge distribution is Poissonian above $T_c$, but it deviates\nfrom the convoluted Poisson at low temperature. The topological susceptibility\ndecreases rapidly below $T_c$, showing the apparent restoration of the $U(1)_A$\nsymmetry already at $T \\approx T_c$."
    },
    {
        "anchor": "Pionic couplings to the lowest heavy-light mesons of positive and\n  negative parity: We present the method and compute the strong couplings of the lowest and\nfirst orbitally excited heavy-light mesons to a soft pion in the static heavy\nquark limit on the lattice. Besides the usual g^ and \\~g couplings, we were\nable to make the first computation of the coupling h using the relevant radial\ndistributions. Our results are obtained from the simulations of QCD with Nf=2\nlight Wilson-Clover quarks, combined with the improved static quark actions.\nThe hierarchy among couplings that emerges from our study is \\~g < g^ < h.",
        "positive": "Baryon axial charges from Chirally Improved fermions - first results: We present first results from dynamical Chirally Improved (CI) fermion\nsimulations for the axial charge $G_A$ of various hadrons. We work with 16^3x32\nlattices of spatial extent 2.4 fm and use the variational method with a\nsuitable basis of Jacobi-smeared interpolators to suppress contaminations from\nexcited states."
    },
    {
        "anchor": "Domain wall quarks and kaon weak matrix elements: We present lattice calculations of kaon matrix elements with domain wall\nfermions. Using lattices with beta=5.85, 6.0, and 6.3, we estimate B_K(approx 2\nGeV)=0.628(47) in quenched QCD which is consistent with previous calculations.\nAt beta=6.0 and 5.85 we find the ratio f_K/m_rho in agreement with the\nexperimental value, within errors. These results support expectations that O(a)\nerrors are exponentially suppressed in low energy (E<< a^{-1}) observables, and\nindicate that domain wall fermions have good scaling behavior at relatively\nstrong couplings. We also demonstrate that the axial current numerically\nsatisfies the lattice analog of the usual continuum axial Ward identity.",
        "positive": "Gauge Fixing on the Lattice and the Gibbs Phenomenon: We discuss global gauge fixing on the lattice, specifically to the lattice\nLandau gauge, with the goal of understanding the question of why the process\nbecomes extremely slow for large lattices. We construct an artificial\n\"gauge-fixing\" problem which has the essential features encountered in\nactuality. In the limit in which the size of the system to be gauge fixed\nbecomes infinite, the problem becomes equivalent to finding a series expansion\nin functions which are related to the Jacobi polynomials. The series converges\nslowly, as expected. It also converges non-uniformly, which is an observed\ncharacteristic of gauge fixing. In the limiting example, the non-uniformity\narises through the Gibbs phenomenon."
    },
    {
        "anchor": "A lattice study of the strangeness content of the nucleon: We determine the quark contributions to the nucleon spin Delta s, Delta u and\nDelta d as well as their contributions to the nucleon mass, the sigma-terms.\nThis is done by computing both, the quark line connected and disconnected\ncontributions to the respective matrix elements, using the non-perturbatively\nimproved Sheikholeslami-Wohlert Wilson Fermionic action. We simulate n_F=2 mass\ndegenerate sea quarks with a pion mass of about 285 MeV and a lattice spacing a\n= 0.073 fm. The renormalization of the matrix elements involves mixing between\ncontributions from different quark flavours. The pion-nucleon sigma-term is\nextrapolated to physical quark masses exploiting the sea quark mass dependence\nof the nucleon mass. We obtain the renormalized value sigma_{piN}=38(12) MeV at\nthe physical point and the strangeness fraction\nf_{Ts}=sigma_s/m_N=0.012(14)(+10-3) at our larger than physical sea quark mass.\nFor the strangeness contribution to the nucleon spin we obtain in the MSbar\nscheme at the renormalization scale of 2.71 GeV Delta s = -0.020(10)(2).",
        "positive": "Zooming-in on the SU(2) fundamental domain: For SU(2) gauge theories on the three-sphere we analyse the Gribov horizon\nand the boundary of the fundamental domain in the 18 dimensional subspace that\ncontains the tunnelling path and the sphaleron and on which the energy\nfunctional is degenerate to second order in the fields. We prove that parts of\nthis boundary coincide with the Gribov horizon with the help of bounds on the\nfundamental modular domain."
    },
    {
        "anchor": "Precision check on triviality of phi^4 theory by a new simulation method: We report precise simulations of phi^4 theory in the Ising limit. A recent\ntechnique to stochastically evaluate the all-order strong coupling expansion is\ncombined with exact identities in the closely related Aizenman random current\nrepresentation. In this way high precision estimates of the renormalized\ncoupling are possible at low CPU cost. As a sample application we present\nresults for the unbroken phase of the Ising model in dimensions 3, 4 and 5 and\ninvestigate the question of triviality by studying a finite size scaling\ncontinuum limit.",
        "positive": "Charm quark system at the physical point of 2+1 flavor lattice QCD: We investigate the charm quark system using the relativistic heavy quark\naction on 2+1 flavor PACS-CS configurations previously generated on $32^3\n\\times 64$ lattice. The dynamical up-down and strange quark masses are set to\nthe physical values by using the technique of reweighting to shift the quark\nhopping parameters from the values employed in the configuration generation. At\nthe physical point, the lattice spacing equals $a^{-1}=2.194(10)$ GeV and the\nspatial extent $L=2.88(1)$ fm. The charm quark mass is determined by the\nspin-averaged mass of the 1S charmonium state, from which we obtain $m_{\\rm\ncharm}^{\\msbar}(\\mu = m_{\\rm charm}^{\\msbar}) = 1.260(1)(6)(35)$ GeV, where the\nerrors are due to our statistics, scale determination and renormalization\nfactor. An additional systematic error from the heavy quark is of order\n$\\alpha_s^2 f(m_Q a)(a \\Lambda_{QCD})$, which is estimated to be a percent\nlevel if the factor $f(m_Q a)$ analytic in $m_Q a$ is of order unity. Our\nresults for the charmed and charmed-strange meson decay constants are\n$f_D=226(6)(1)(5)$ MeV, $f_{D_s}=257(2)(1)(5)$ MeV, again up to the heavy quark\nerrors of order $\\alpha_s^2 f(m_Q a)(a \\Lambda_{QCD})$. Combined with the CLEO\nvalues for the leptonic decay widths, these values yield $|V_{cd}| =\n0.205(6)(1)(5)(9)$, $|V_{cs}| = 1.00(1)(1)(3)(3)$, where the last error is on\naccount of the experimental uncertainty of the decay widths."
    },
    {
        "anchor": "The Renormalized Trajectory of the O(N) Non-linear Sigma Model: The renormalized trajectory (RT) is determined from two different Monte Carlo\nrenormalization group techniques with $\\delta$-function block spin\ntransformation in the multi-dimensional coupling parameter space of the\ntwo-dimensional non-linear sigma model with O(3) symmetry. At a correlation\nlength $\\xi \\approx 3$-$5$, the RT is shown to break away from the straight\nline of the fixed point trajectory (FPT) which is orthogonal to the critical\nsurface and originates from the ultraviolet fixed point (UVFP). The large $N$\ncalculation of the RT is also presented in the coupling parameter space of the\nmost general bilinear Hamiltonian. The RT in the large $N$ approximation\nexhibits a similar shape with the sharp break occurring at a somewhat smaller\ncorrelation length.",
        "positive": "Accelerating Wilson Fermion Matrix Inversions by Means of the Stabilized\n  Biconjugate Gradient Algorithm: The stabilized biconjugate gradient algorithm BiCGStab recently presented by\nvan der Vorst is applied to the inversion of the lattice fermion operator in\nthe Wilson formulation of lattice Quantum Chromodynamics. Its computational\nefficiency is tested in a comparative study against the conjugate gradient and\nminimal residual methods. Both for quenched gauge configurations at beta= 6.0\nand gauge configurations with dynamical fermions at beta=5.4, we find BiCGStab\nto be superior to the other methods. BiCGStab turns out to be particularly\nuseful in the chiral regime of small quark masses."
    },
    {
        "anchor": "Dynamics of a lattice 2-group gauge theory model: We study a simple lattice model with local symmetry, whose construction is\nbased on a crossed module of finite groups. Its dynamical degrees of freedom\nare associated both to links and faces of a four-dimensional lattice. In\nspecial limits the discussed model reduces to certain known topological quantum\nfield theories. In this work we focus on its dynamics, which we study both\nanalytically and using Monte Carlo simulations. We prove a factorization\ntheorem which reduces computation of correlation functions of local observables\nto known, simpler models. This, combined with standard Krammers-Wannier type\ndualities, allows us to propose a detailed phase diagram, which form is then\nconfirmed in numerical simulations. We describe also topological charges\npresent in the model, its symmetries and symmetry breaking patterns. The\ncorresponding order parameters are the Polyakov loop and its generalization,\nwhich we call a Polyakov surface. The latter is particularly interesting, as it\nis beyond the scope of the factorization theorem. As shown by the numerical\nresults, expectation value of Polyakov surface may serve to detects all phase\ntransitions and is sensitive to a value of the topological charge.",
        "positive": "Kaon B parameter from quenched domain-wall QCD: We report on a calculation of $B_K$ with domain wall fermion action in\nquenched QCD. Simulations are made with a renormalization group improved gauge\naction at $\\beta=2.6$ and 2.9 corresponding to $a^{-1}\\approx 2$GeV and 3GeV.\nEffects due to finite fifth dimensional size $N_5$ and finite spatial size\n$N_\\sigma$ are examined in detail. Matching to the continuum operator is made\nperturbatively at one loop order. We obtain $B_K(\\mu = 2 GeV)=\n0.5746(61)(191)$, where the first error is statistical and the second error\nrepresents an estimate of scaling violation and ${\\cal O}(\\alpha^2)$ errors in\nthe renormalization factor added in quadrature, as an estimate of the continuum\nvalue in the $\\msbar$ scheme with naive dimensional regularization. This value\nis consistent, albeit somewhat small, with $B_K(\\mu = 2 {GeV})= 0.628(42)$\nobtained by the JLQCD Collaboration using the Kogut-Susskind quark action.\nResults for light quark masses are also reported."
    },
    {
        "anchor": "The $N_t=6$ equation of state for two flavor QCD: We improve the calculation of the equation of state for two flavor QCD by\nsimulating on $N_t=6$ lattices at appropriate values of the couplings for the\ndeconfinement/chiral symmetry restoration crossover. For $am_q=0.0125$ the\nenergy density rises rapidly to approximately 1 ${\\rm GeV/fm^3}$ just after the\ncrossover($m_\\pi/m_\\rho\\approx 0.4$ at this point). Comparing with our previous\nresult for $N_t=4$~\\cite{eos}, we find large finite $N_t$ corrections as\nexpected from free field theory on finite lattices. We also provide formulae\nfor extracting the speed of sound from the measured quantities.",
        "positive": "Heavy Baryon Specroscopy from the Lattice: The results of an exploratory lattice study of heavy baryon spectroscopy are\npresented. We have computed the full spectrum of the eight baryons containing a\nsingle heavy quark, on a $24^3\\times 48$ lattice at $\\beta=6.2$, using an\n$O(a)$-improved fermion action. We discuss the lattice baryon operators and\ngive a method for isolating the contributions of the spin doublets\n$(\\Sigma,\\Sigma^*)$, $(\\Xi',\\Xi^*)$ and $(\\Omega,\\Omega^*)$ to the correlation\nfunction of the relevant operator. We compare our results with the available\nexperimental data and find good agreement in both the charm and the beauty\nsectors, despite the long extrapolation in the heavy quark mass needed in the\nlatter case. We also predict the masses of several undiscovered baryons. We\ncompute the $\\Lambda-\\mbox{pseudoscalar meson}$ and $\\Sigma-\\Lambda$ mass\nsplittings. Our results, which have errors in the range $ 10-30\\%$, are in good\nagreement with the experimental numbers. For the $\\Sigma^*-\\Sigma$ mass\nsplitting, we find results considerably smaller than the experimental values\nfor both the charm and the beauty baryons, although in the latter case the\nexperimental results are still preliminary. This is also the case for the\nlattice results for the hyperfine splitting for the heavy mesons."
    },
    {
        "anchor": "Multipolynomial Monte Carlo Trace Estimation: In lattice QCD the calculation of disconnected quark loops from the trace of\nthe inverse quark matrix has large noise variance. A multilevel Monte Carlo\nmethod is proposed for this problem that uses different degree polynomials on a\nmultilevel system. The polynomials are developed from the GMRES algorithm for\nsolving linear equations. To reduce orthogonalization expense, the highest\ndegree polynomial is a composite or double polynomial found with a polynomial\npreconditioned GMRES iteration. Matrix deflation is used in three different\nways: in the Monte Carlo levels, in the main solves, and in the deflation of\nthe highest level double polynomial. A numerical comparison with optimized\nHutchinson is performed on a quenched \\(24^4\\) lattice. The results demonstrate\nthat the new Multipolynomial Monte Carlo method can significantly improve the\ntrace computation for matrices that have a difficult spectrum due to small\neigenvalues.}",
        "positive": "Isospin Effects by Mass Reweighting: Most of today's lattice simulations are performed in the isospin symmetric\nlimit of the light quark sector. Mass reweighting is a technique to include\neffects of isospin breaking in the sea quarks at moderate numerical cost. We\nwill give a summary of our recent results on fine lattices with light quark\nmasses and will show how light quark masses can be extracted by introducing\nsuitable tuning conditions for the bare mass parameters.\n  In general the reweighting factor introduces additional fluctuations and thus\nincreases the statistical uncertainties. In the case of isospin reweighting\nthis factor is a ratio of fermion determinants. The stochastic evaluation of\nthe determinants potentially leads to stochastic noise in observables. We show\nthe quark mass and the volume dependence of these fluctuations."
    },
    {
        "anchor": "Lattice-continuum relations for 3d SU(N)+Higgs theories: 3d lattice studies have recently attracted a lot of attention, especially in\nconnection with finite temperature field theories. One ingredient in these\nstudies is a perturbative computation of the 2-loop lattice counterterms, which\nare exact in the continuum limit. We extend previous such results to SU(N)\ngauge theories with Higgs fields in the fundamental and adjoint\nrepresentations. The fundamental SU(3)xSU(2) case might be relevant for the\nelectroweak phase transition in the MSSM, and the adjoint case for the GUT\nphase transition and for QCD in the high temperature phase. We also revisit the\nstandard SU(2)xU(1) and U(1) theories.",
        "positive": "Meson and baryon spectrum for QCD with two light dynamical quarks: We present results of meson and baryon spectroscopy using the Chirally\nImproved Dirac operator on lattices of size 16**3 x 32 with two mass-degenerate\nlight sea quarks. Three ensembles with pion masses of 322(5), 470(4) and 525(7)\nMeV and lattice spacings close to 0.15 fm are investigated. Results on ground\nand excited states for several channels are given, including spin two mesons\nand hadrons with strange valence quarks. The analysis of the states is done\nwith the variational method, including two kinds of Gaussian sources and\nderivative sources. We obtain several ground states fairly precisely and find\nradial excitations in various channels. Excited baryon results seem to suffer\nfrom finite size effects, in particular at small pion masses. We discuss the\npossible appearance of scattering states in various channels, considering\nmasses and eigenvectors. Partially quenched results in the scalar channel\nsuggest the presence of a 2-particle state, however, in most channels we cannot\nidentify them. Where available, we compare our results to results of quenched\nsimulations using the same action."
    },
    {
        "anchor": "A lattice QCD perspective on weak decays of b and c quarks Snowmass 2022\n  White Paper: Lattice quantum chromodynamics has proven to be an indispensable method to\ndetermine nonperturbative strong contributions to weak decay processes. In this\nwhite paper for the Snowmass community planning process we highlight\nachievements and future avenues of research for lattice calculations of weak\n$b$ and $c$ quark decays, and point out how these calculations will help to\naddress the anomalies currently in the spotlight of the particle physics\ncommunity. With future increases in computational resources and algorithmic\nimprovements, percent level (and below) lattice determinations will play a\ncentral role in constraining the standard model or identifying new physics.",
        "positive": "The potential of the effective Polyakov line action from the underlying\n  lattice gauge theory: I adapt a numerical method, previously applied to investigate the Yang-Mills\nvacuum wavefunctional, to the problem of extracting the effective Polyakov line\naction from SU(N) lattice gauge theories, with or without matter fields. The\nmethod can be used to find the variation of the effective Polyakov line action\nalong any trajectory in field configuration space; this information is\nsufficient to determine the potential term in the action, and strongly\nconstrains the possible form of the kinetic term. The technique is illustrated\nfor both pure and gauge-Higgs SU(2) lattice gauge theory at finite temperature.\nA surprise, in the pure gauge theory, is that the potential of the\ncorresponding Polyakov line action contains a non-analytic (yet\ncenter-symmetric) term proportional to |P|^3, where P is the trace of the\nPolyakov line at a given point, in addition to the expected analytic terms\nproportional to even powers of P."
    },
    {
        "anchor": "Quantum Theory with Many Degrees of Freedom from Monte Carlo Hamiltonian: With our recently proposed effective Hamiltonian via Monte Carlo, we are able\nto compute low energy physics of quantum systems. The advantage is that we can\nobtain not only the spectrum of ground and excited states, but also wave\nfunctions. The previous work has shown the success of this method in\n(1+1)-dimensional quantum mechanical systems. In this work we apply it to\nhigher dimensional systems.",
        "positive": "Controlling quark mass determinations non-perturbatively in\n  three-flavour QCD: The determination of quark masses from lattice QCD simulations requires a\nnon-perturbative renormalization procedure and subsequent scale evolution to\nhigh energies, where a conversion to the commonly used MS-bar scheme can be\nsafely established. We present our results for the non-perturbative running of\nrenormalized quark masses in Nf=3 QCD between the electroweak and a hadronic\nenergy scale, where lattice simulations are at our disposal. Recent theoretical\nadvances in combination with well-established techniques allows to follow the\nscale evolution to very high statistical accuracy, and full control of\nsystematic effects."
    },
    {
        "anchor": "All About the Neutron from Lattice QCD: I describe how simulations of lattice QCD using the path integral formulation\nprovide the two basic quantum mechanical properties of QCD, its ground state in\nwhich correlation functions are calculated, and Fock state wavefunctions\nbetween which matrix elements of operators are calculated. Both constructs are\nstochastic, so unfortunately one gets no intuitive picture or even a\nqualitative understanding of what they look like, nevertheless they contain and\ndisplay all the subtleties of the quantum field theory. Today, these\nsimulations provide many quantities that are impacting phenomenology and\nexperiments. I illustrate the methods and the steps in the analysis using, as\nexamples, three observables: the isovector charges of the nucleon, the\ncontribution of the quark's intrinsic spin to the nucleon spin, and the\npion-nucleon sigma term.",
        "positive": "The relevance of center vortices: We show remnants of chiral symmetry breaking in the center-projected theory.\nWe construct and study an unambiguous definition of center vortices."
    },
    {
        "anchor": "One-loop matching factors for staggered bilinear operators with improved\n  gauge actions: We present results for one-loop perturbative matching factors using bilinear\noperators composed of improved staggered fermions, using unimproved (Wilson)\nand improved (Symanzik, Iwasaki, and DBW2) gluon actions. We consider two\nfermions actions---HYP/$\\bar{\\text{Fat7}}$-smeared and \"asqtad\". The former is\nbeing used in calculations of electroweak matrix elements, while the latter\nhave been used extensively by the MILC collaboration. We observe that using the\nimproved gluon action leads to small reductions in the perturbative\ncorrections, but that these reductions are smaller than those obtained when\nmoving from the tadpole-improved naive staggered action to either HYP-smeared\nor asqtad action.",
        "positive": "Physical Results from 2+1 Flavor Domain Wall QCD and SU(2) Chiral\n  Perturbation Theory: We have simulated QCD using 2+1 flavors of domain wall quarks on a $(2.74\n{\\rm fm})^3$ volume with an inverse lattice scale of $a^{-1} = 1.729(28)$ GeV.\nThe up and down (light) quarks are degenerate in our calculations and we have\nused four values for the ratio of light quark masses to the strange (heavy)\nquark mass in our simulations: 0.217, 0.350, 0.617 and 0.884. We have measured\npseudoscalar meson masses and decay constants, the kaon bag parameter $B_K$ and\nvector meson couplings. We have used SU(2) chiral perturbation theory, which\nassumes only the up and down quark masses are small, and SU(3) chiral\nperturbation theory to extrapolate to the physical values for the light quark\nmasses. While next-to-leading order formulae from both approaches fit our data\nfor light quarks, we find the higher order corrections for SU(3) very large,\nmaking such fits unreliable. We also find that SU(3) does not fit our data when\nthe quark masses are near the physical strange quark mass. Thus, we rely on\nSU(2) chiral perturbation theory for accurate results. We use the masses of the\n$\\Omega$ baryon, and the $\\pi$ and $K$ mesons to set the lattice scale and\ndetermine the quark masses. We then find $f_\\pi = 124.1(3.6)_{\\rm\nstat}(6.9)_{\\rm syst} {\\rm MeV}$, $f_K = 149.6(3.6)_{\\rm stat}(6.3)_{\\rm syst}\n{\\rm MeV}$ and $f_K/f_\\pi = 1.205(0.018)_{\\rm stat}(0.062)_{\\rm syst}$. Using\nnon-perturbative renormalization to relate lattice regularized quark masses to\nRI-MOM masses, and perturbation theory to relate these to $\\bar{\\rm MS}$ we\nfind $ m_{ud}^{\\bar{\\rm MS}}(2 {\\rm GeV}) = 3.72(0.16)_{\\rm stat}(0.33)_{\\rm\nren}(0.18)_{\\rm syst} {\\rm MeV}$ and $m_{s}^{\\bar{\\rm MS}}(2 {\\rm GeV}) =\n107.3(4.4)_{\\rm stat}(9.7)_{\\rm ren}(4.9)_{\\rm syst} {\\rm MeV}$."
    },
    {
        "anchor": "The Dual Meissner Effect and Magnetic Displacement Currents: The dual Meissner effect is observed without monopoles in quenched $SU (2)$\nQCD with Landau gauge-fixing. Magnetic displacement currents which are\ntime-dependent Abelian magnetic fields play a role of solenoidal currents\nsqueezing Abelian electric fields. Monopoles are not always necessary to the\ndual Meissner effect. The squeezing of the electric flux means the dual London\nequation and the massiveness of the Abelian electric fields as an asymptotic\nfield. The mass generation of the Abelian electric fields is related to a gluon\ncondensate $<A^a_{\\mu}A^a_{\\mu}>\\neq 0$ of mass dimension 2.",
        "positive": "Recent progress in lattice calculations of properties of open-charm\n  mesons: Recent progress in lattice calculations of properties of open-charm mesons,\nboth regular and exotic, is reviewed, with an emphasis on spectroscopy. After\nreviewing recent calculations of excited state energy levels I will discuss\nprogress in extracting hadronic masses and widths of charmed states from\nLattice QCD simulations including low-lying scattering channels directly, to\ndetermine phase shift data and bound state/ resonance properties. With regard\nto other properties results from recent calculations of the $DD^*\\pi$ and\n$DD\\rho$, $D^*D^*\\rho$ couplings are presented. Beyond regular mesons, searches\nfor explicitly exotic (tetraquark) states are also reviewed."
    },
    {
        "anchor": "Matrix Elements of the Singlet Axial Current in the Proton: We present a method to estimate the matrix element of the singlet axial\ncurrent within a polarized proton state using lattice QCD. The method relies on\nusing the Adler-Bell-Jackiw anomaly and gives the desired result in the chiral\nlimit. We show that this method fails in the quenched approximation. For heavy\nquarks one does not expect much difference between simulations including\ndynamical quarks and those done in the quenched approximation. For that reason\nwe explore numerical methods on an existing set of quenched configurations. The\ndata obtained in this exploratory study show a poor statistical signal.",
        "positive": "Static quark anti-quark free and internal energy in 2-flavor QCD and\n  bound states in the QGP: We present results on heavy quark free energies in 2-flavour QCD. The\ntemperature dependence of the interaction between static quark anti-quark pairs\nwill be analyzed in terms of temperature dependent screening radii, which give\na first estimate on the medium modification of (heavy quark) bound states in\nthe quark gluon plasma. Comparing those radii to the (zero temperature) mean\nsquared charge radii of cha rmonium states indicates that the $J/\\psi$ may\nsurvive the phase transition as a bound state, while $\\chi_c$ and $\\psi'$ are\nexpected to show significant thermal modifications at temperatures close to the\ntransition. Furthermore we will analyze the relation between heavy quark free\nenergies, entropy contributions and internal energy and discuss their relation\nto potential models used to analyze the melting of heavy quark bound states\nabove the deconfinement temperature. Results of different groups and various\npotential models for bound states in the deconfined phase of QCD are compared."
    },
    {
        "anchor": "The Critical Exponents of Crystalline Random Surfaces: We report on a high statistics numerical study of the crystalline random\nsurface model with extrinsic curvature on lattices of up to $64^2$ points. The\ncritical exponents at the crumpling transition are determined by a number of\nmethods all of which are shown to agree within estimated errors. The\ncorrelation length exponent is found to be $\\nu=0.71(5)$ from the\ntangent-tangent correlation function whereas we find $\\nu=0.73(6)$ by assuming\nfinite size scaling of the specific heat peak and hyperscaling. These results\nimply a specific heat exponent $\\alpha=0.58(10)$; this is a good fit to the\nspecific heat on a $64^2$ lattice with a $\\chi^2$ per degree of freedom of 1.7\nalthough the best direct fit to the specific heat data yields a much lower\nvalue of $\\alpha$. Our measurements of the normal-normal correlation functions\nsuggest that the model in the crumpled phase is described by an effective field\ntheory which deviates from a free field theory only by super-renormalizable\ninteractions.",
        "positive": "Pseudoscalar flavor-singlet mesons from lattice QCD: We investigate the masses and mixing of $\\eta$, $\\eta'$ mesons in the\nframework of twisted mass lattice QCD with $N_f=2+1+1$ dynamical quark flavors.\nFor the first time we perform a controlled chiral and continuum extrapolation\nto obtain physical results. To this end, we have analyzed 17 gauge ensembles\nwith pion masses ranging from $220\\,\\mathrm{MeV}$ to $500\\,\\mathrm{MeV}$ and at\nthree values of the lattice spacing. This calculation became feasible through\nthe application of a powerful variance reduction technique for the computation\nof quark-disconnected diagrams together with several improvements in the final\nanalysis, including a correction of the relevant correlation functions for\nresidual topological finite volume effects. We obtain physical results for the\nmasses $M_{\\eta}=557(11)_\\mathrm{stat}(03)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$ and\n$M_{\\eta'}=911(64)_\\mathrm{stat}(03)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$, as well\nas the mixing angle in the quark flavor basis\n$\\phi=38.8(2.2)_\\mathrm{stat}(2.4)_{\\chi\\mathrm{PT}}^\\circ$, in excellent\nagreement with other results from phenomenology. Similarly, for the physical\nvalues of the decay constant parameters we find\n$f_l=125(5)_\\mathrm{stat}(6)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$ and\n$f_s=178(4)_\\mathrm{stat}(1)_{\\chi\\mathrm{PT}}\\,\\mathrm{MeV}$. Finally, we\npresent a test of the Veneziano Witten formula using our lattice data."
    },
    {
        "anchor": "Continuum limit of parton distribution functions from the\n  pseudo-distribution approach on the lattice: Precise exploration of the partonic structure of the nucleon is one of the\nmost important aims of high-energy physics. In recent years, it has become\npossible to address this topic with first-principle lattice QCD investigations.\nIn this talk, we focus on the so-called pseudo-distribution approach to\ndetermine the isovector unpolarized PDFs. In particular, we employ three\nlattice spacings to study discretization effects and extract the distributions\nin the continuum limit, at a pion mass of around 370 MeV. Also, for the first\ntime with pseudo-PDFs, we explore effects of the 2-loop matching from pseudo-\nto light-cone distributions.",
        "positive": "New Universality Classes in One--Dimensional $O(N)$--Invariant\n  Spin--Models with an $n$--Parametric Action: An action with $n$ parameters, which generalizes the $O(N) - R P^{N-1}$\n-model, is considered in one dimension for general $N$. We use asymptotic\nexpansion techniques to determine where the model becomes critical and show\nthat for the actions considered there exists a family of hypersurfaces whose\nasymptotic behaviour determines a one-parameter family of new universality\nclasses. They interpolate between the $O(N)$-vector-model-class and the $R\nP^{N-1}$-model-class. Furthermore continuum limits are discussed, including the\nexceptional case $N=2$."
    },
    {
        "anchor": "Visualizing resonances in finite volume: In present work, we explore and experiment an alternative approach of\nstudying resonance properties in finite volume. By analytic continuing finite\nlattice size $L$ into complex plane, the oscillating behavior of finite volume\nGreen's function is mapped into infinite volume Green's function corrected by\nexponentially decaying finite volume effect. The analytic continuation\ntechnique thus can be applied to study resonance properties directly in finite\nvolume dynamical equations.",
        "positive": "Spectroscopy, Scaling and Critical Indices in Strongly Coupled Quenched\n  QED: The interplay of spectroscopy, scaling laws and critical indices is studied\nin strongly coupled quenched QED. Interpreted as a model of technicolor having\nstrong interactions at short distances, we predict the techni-meson mass\nspectrum in a simplified model of a dynamically generated top quark mass $M_f$.\nOur results support the strict inequality that the techni-sigma mass $M_\\sigma$\nis less than twice the dynamical quark mass $M_f$, and confirm that the\ntechni-pion is a Nambu-Goldstone boson. The level ordering $0 = M_\\pi <\nM_\\sigma < 2M_f < M_\\rho < M_{a1} $ is found.An equation of state, and scaling\nlaws are derived for the techni-meson masses by exploiting correlation length\nscaling. The resulting universality relations are confirmed by simulations on\n$16^4$, $32\\times 16^3$ and $32^4$ lattices. The anomalous dimension $\\eta$ is\nmeasured to be approximatively $0.50$ in good agreement with past lattice\nsimulations and hyperscaling relations, as well as with the analytic solution\nof the quenched, planar gauged Nambu-Jona Lasinio model solved by continuum\nSchwinger-Dyson equation techniques."
    },
    {
        "anchor": "Deconfinement transition and dimensional cross-over in the 3D gauge\n  Ising model: We present a high precision Monte Carlo study of the finite temperature $Z_2$\ngauge theory in 2+1 dimensions. The duality with the 3D Ising spin model allows\nus to use powerful cluster algorithms for the simulations. For temporal\nextensions up to $N_t=16$ we obtain the inverse critical temperature with a\nstatistical accuracy comparable with the most accurate results for the bulk\nphase transition of the 3D Ising model. We discuss the predictions of T. W.\nCapehart and M.E. Fisher for the dimensional crossover from 2 to 3 dimensions.\nOur precise data for the critical exponents and critical amplitudes confirm the\nSvetitsky-Yaffe conjecture. We find deviations from Olesen's prediction for the\ncritical temperature of about 20%.",
        "positive": "Integrable structures in LGTs near the deconfinement transition: In this contribution we review some recent results about the emergence of 2D\nintegrable systems in 3D Lattice Gauge Theories near the deconfinement\ntransition. We focus on some concrete examples involving the flux tube\nthickness, the ratio of k-string tensions and Polyakov loops correlators in\nvarious models."
    },
    {
        "anchor": "Superconductivity and Chiral Symmetry Breaking with Fermion Clusters: Cluster variables have recently revolutionized numerical work in certain\nmodels involving fermionic variables. This novel representation of fermionic\npartition functions is continuing to find new applications. After describing\nresults from a study of a two dimensional Hubbard type model that confirm a\nsuperconducting transition in the Kosterlitz-Thouless universality class, we\nshow how a cluster type algorithm can be devised to study the chiral limit of\nstrongly coupled lattice gauge theories with staggered fermions.",
        "positive": "The QCD Equation of State with almost Physical Quark Masses: We present results on the equation of state in QCD with two light quark\nflavors and a heavier strange quark. Calculations with improved staggered\nfermions have been performed on lattices with temporal extent Nt =4 and 6 on a\nline of constant physics with almost physical quark mass values; the pion mass\nis about 220 MeV, and the strange quark mass is adjusted to its physical value.\nHigh statistics results on large lattices are obtained for bulk thermodynamic\nobservables, i.e. pressure, energy and entropy density, at vanishing quark\nchemical potential for a wide range of temperatures, 140 MeV < T < 800 MeV. We\npresent a detailed discussion of finite cut-off effects which become\nparticularly significant for temperatures larger than about twice the\ntransition temperature. At these high temperatures we also performed\ncalculations of the trace anomaly on lattices with temporal extent Nt=8.\nFurthermore, we have performed an extensive analysis of zero temperature\nobservables including the light and strange quark condensates and the static\nquark potential at zero temperature. These are used to set the temperature\nscale for thermodynamic observables and to calculate renormalized observables\nthat are sensitive to deconfinement and chiral symmetry restoration and become\norder parameters in the infinite and zero quark mass limits, respectively."
    },
    {
        "anchor": "Towards the N_f=2 deconfinement transition temperature with O(a)\n  improved Wilson fermions: A lot of effort in lattice simulations over the last years has been devoted\nto studies of the QCD deconfinement transition. Most state-of-the-art\nsimulations use rooted staggered fermions, while Wilson fermions are affected\nby large systematic uncertainties, such as coarse lattices or heavy sea quarks.\nHere we report on an ongoing study of the transition, using two degenerate\nflavours of nonperturbatively $\\Ord(a)$ improved Wilson fermions. We start with\n$N_{t}=12$ and 16 lattices and pion masses of 600 to 450 MeV, aiming at chiral\nand continuum limits with light quarks.",
        "positive": "$B_s$-$\\bar{B_s}$ mixing from lattice QCD: We study the $B^0_s-\\bar{B^0_s}$ mixing amplitude in Standard Model by\ncomputing the relevant hadronic matrix element in the static limit of lattice\nHQET with the Neuberger light quark action. In the quenched approximation, and\nafter matching to the $\\bar{\\rm MS}$ scheme in QCD, we obtain\n$\\hat{B}^{\\bar{\\rm MS},{\\rm NLO}}_{B_s}(m_b)=0.940(16)(22)$."
    },
    {
        "anchor": "Hybrid Monte Carlo with Wilson Dirac operator on the Fermi GPU: In this article we present our implementation of a Hybrid Monte Carlo\nalgorithm for Lattice Gauge Theory using two degenerate flavours of\nWilson-Dirac fermions on a Fermi GPU. We find that using registers instead of\nglobal memory speeds up the code by almost an order of magnitude. To map the\narray variables to scalars, so that the compiler puts them in the registers, we\nuse code generators. Our final program is more than 10 times faster than a\ngeneric single CPU.",
        "positive": "Search for the possible S=+1 Pentaquark states in Quenched Lattice QCD: We study spin $\\frac12$ hadronic states in quenched lattice QCD to search for\na possible $S=+1$ pentaquark resonance. Simulations are carried out on\n$8^3\\times 24$, $10^3\\times 24$, $12^3\\times 24$ and $16^3\\times 24$ lattices\nat $\\beta$=5.7 at the quenched level with the standard plaquette gauge action\nand the Wilson quark action. We adopt a Dirichlet boundary condition in the\ntime direction for the quark to circumvent the possible contaminations due to\nthe (anti)periodic boundary condition for the quark field, which are peculiar\nto the pentaquark. By diagonalizing the $2\\times 2$ correlation matrices\nconstructed from two independent operators with the quantum numbers\n$(I,J)=(0,\\frac12)$, we successfully obtain the energies of the lowest state\nand the 2nd-lowest state in this channel. The analysis of the volume dependence\nof the energies and spectral weight factors indicates that a resonance state is\nlikely to exist slightly above the NK threshold in $(I,J^P)=(0,\\frac12^-)$\nchannel."
    },
    {
        "anchor": "Chiral Determinant as an Overlap of Two Vacua: The effective action induced by chiral fermions can be written, formally, as\nan overlap of two states. These states are the Fock ground states of\nHamiltonians for fermions in even dimensional space with opposite sign mass\nterms coupled to identical static vector potentials. A perturbative analysis of\nthe overlap in the continuum framework produces the correct anomaly for Abelian\ngauge fields in two dimensions. When a lattice transfer matrix formalism is\napplied in the direction perpendicular to a domain wall on which chiral\nfermions live a lattice version of the overlap is obtained. The real part of\nthe overlap is nonperturbatively defined and previous work indicates that the\nreal part of the vacuum polarization tensor in four dimensions has the correct\ncontinuum limit for a chiral theory. The phase of the overlap represents the\nimaginary part of the chiral action and suffers from ambiguities.",
        "positive": "The chirally improved quark propagator and restoration of chiral\n  symmetry: The chirally improved (CI) quark propagator in Landau gauge is calculated in\ntwo flavor lattice Quantum Chromodynamics. Its wave-function renormalization\nfunction $Z(p^2)$ and mass function $M(p^2)$ are studied. To minimize lattice\nartifacts, tree-level improvement of the propagator and tree-level correction\nof the lattice dressing functions is applied. Subsequently the CI quark\npropagator under Dirac operator low-mode removal is investigated. The\ndynamically generated mass in the infrared domain of the mass function is found\nto dissolve continuously as a function of the reduction level and strong\nsuppression of $Z(p^2)$ for small momenta is observed."
    },
    {
        "anchor": "Quantum algorithms for transport coefficients in gauge theories: In the future, ab initio quantum simulations of heavy ion collisions may\nbecome possible with large-scale fault-tolerant quantum computers. We propose a\nquantum algorithm for studying these collisions by looking at a class of\nobservables requiring dramatically smaller volumes: transport coefficients.\nThese form nonperturbative inputs into theoretical models of heavy ions; thus,\ntheir calculation reduces theoretical uncertainties without the need for a\nfull-scale simulation of the collision. We derive the necessary lattice\noperators in the Hamiltonian formulation and describe how to obtain them on\nquantum computers. Additionally, we discuss ways to efficiently prepare the\nrelevant thermal state of a gauge theory.",
        "positive": "Local gauge symmetry on optical lattices?: The versatile technology of cold atoms confined in optical lattices allows\nthe creation of a vast number of lattice geometries and interactions, providing\na promising platform for emulating various lattice models. This opens the\npossibility of letting nature take care of sign problems and real time\nevolution in carefully prepared situations. Up to now, experimentalists have\nsucceeded to implement several types of Hubbard models considered by condensed\nmatter theorists. In this proceeding, we discuss the possibility of extending\nthis effort to lattice gauge theory. We report recent efforts to establish the\nstrong coupling equivalence between the Fermi Hubbard model and SU(2) pure\ngauge theory in 2+1 dimensions by standard determinantal methods developed by\nRobert Sugar and collaborators. We discuss the possibility of using dipolar\nmolecules and external fields to build models where the equivalence holds\nbeyond the leading order in the strong coupling expansion."
    },
    {
        "anchor": "A Study of Meson Correlators at Finite Temperature: We present results for mesonic propagators in temporal and spatial directions\nat T below and above the deconfining transition in quenched QCD. Anisotropic\nlattices are used to get enough information in the temporal direction. We use\nthe Wilson fermion action for light quarks and Fermilab action for heavy\nquarks.",
        "positive": "B and bottomonium spectroscopy from lattice NRQCD with charm in the sea: We give results for B, Bs, Bc and bottomonium spectroscopy using NRQCD heavy\nquarks and HISQ valence and sea quarks. Five MILC ensembles of gluon\nconfigurations with three values of the lattice spacing and m(light)/m(strange)\nvalues down to 0.1 are used that include 2+1+1 flavours of sea quark.\nSystematic errors in the NRQCD action are improved through the radiative\ncorrection of the coefficients of terms at v^4. Improved results for S-wave and\nP-wave bottomonium states are discussed as well as a prediction for the full\nD-wave spectrum. Preliminary results for the ground state B meson masses are\nalso presented."
    },
    {
        "anchor": "A proposal of a Renormalization Group transformation: We propose a family of renormalization group transformations characterized by\nfree parameters that may be tuned in order to reduce the truncation effects. As\na check we test them in the three dimensional XY model. The Schwinger--Dyson\nequations are used to study the renormalization group flow.",
        "positive": "Equilibrium Thermodynamics of Lattice QCD: Lattice QCD allows us to simulate QCD at non-zero temperature and/or\ndensities. Such equilibrium thermodynamics calculations are relevant to the\nphysics of relativistic heavy-ion collisions. I give a brief review of the\nfield with emphasis on our work."
    },
    {
        "anchor": "Anisotropy tuning with the Wilson flow: We use the Wilson flow to define the gauge anisotropy at a given physical\nscale. We demonstrate the use of the anisotropic flow by performing the tuning\nof the bare gauge anisotropy in the tree-level Symanzik action for several\nlattice spacings and target anisotropies. We use this method to tune the\nanisotropy parameters in full QCD, where we also exploit the diminishing effect\nof a well chosen smearing on the renormalization of the fermion anisotropy.",
        "positive": "Scaling test of the P4-improved staggered fermion action: We present a scaling study of the QCD spectrum using a smeared P4 staggered\nfermion formulation, in which three, five, and seven-link staples are added to\nreduce the effects of flavor symmetry breaking. These studies are performed on\nquenched lattices generated using the one-loop improved Symanzik gauge action,\nwith Beta=10/g^2=7.40,7.75,8.00. The corresponding lattice spacings are a = .31\nfm, .21 fm, and .14 fm. Particularly, we study the O(a^2) flavor symmetry\nviolations in the pion spectrum as well as the scaling dependence of m_rho,\nmeasured in physical units, on lattice spacing. These results are compared\nagainst previous results for the Asqtad action."
    },
    {
        "anchor": "Topological properties of minimally doubled fermions in two space-time\n  dimensions: The two-dimensional Schwinger model is used to explore how lattice fermion\noperators perceive the global topological charge $q \\in \\mathbb{Z}$ of a given\nbackground gauge field. We focus on Karsten-Wilczek and Borici-Creutz fermions,\nwhich are minimally doubled, and compare them to Wilson, Brillouin, naive,\nstaggered and Adams fermions. For each operator the eigenvalue spectrum in a\nbackground with $q \\neq 0$ is determined along with the chiralities of the\neigenmodes, and the spectral flow of the pertinent hermitean operator is worked\nout. We find that Karsten-Wilczek and Borici-Creutz fermions perceive the\nglobal topological charge $q$ in the same way as staggered and naive fermions\ndo.",
        "positive": "Investigations in 1+1 dimensional lattice $\u03c6^4$ theory: In this work we perform a detailed numerical analysis of (1+1) dimensional\nlattice $\\phi^4$ theory. We explore the phase diagram of the theory with two\ndifferent parameterizations. We find that symmetry breaking occurs only with a\nnegative mass-squared term in the Hamiltonian. The renormalized mass $m_R$ and\nthe field renormalization constant $Z$ are calculated from both coordinate\nspace and momentum space propagators in the broken symmetry phase. The critical\ncoupling for the phase transition and the critical exponents associated with\n$m_R$, $Z$ and the order parameter are extracted using a finite size scaling\nanalysis of the data for several volumes. The scaling behavior of $Z$ has the\ninteresting consequence that $<\\phi_R>$ does not scale in 1+1 dimensions. We\nalso calculate the renormalized coupling constant $ \\lambda_R$ in the broken\nsymmetry phase. The ratio $ \\lambda_R/m_R^2 $ does not scale and appears to\nreach a value independent of the bare parameters in the critical region in the\ninfinite volume limit."
    },
    {
        "anchor": "$\u039b_b \\to \u039b^*(1520)\\ell^+\\ell^-$ form factors from lattice\n  QCD: We present the first lattice QCD determination of the $\\Lambda_b \\to\n\\Lambda^*(1520)$ vector, axial vector, and tensor form factors that are\nrelevant for the rare decays $\\Lambda_b \\to \\Lambda^*(1520)\\ell^+\\ell^-$. The\nlattice calculation is performed in the $\\Lambda^*(1520)$ rest frame with\nnonzero $\\Lambda_b$ momenta, and is limited to the high-$q^2$ region. An\ninterpolating field with covariant derivatives is used to obtain good overlap\nwith the $\\Lambda^*(1520)$. The analysis treats the $\\Lambda^*(1520)$ as a\nstable particle, which is expected to be a reasonable approximation for this\nnarrow resonance. A domain-wall action is used for the light and strange\nquarks, while the $b$ quark is implemented with an anisotropic clover action\nwith coefficients tuned to produce the correct $B_s$ kinetic mass, rest mass,\nand hyperfine splitting. We use three different ensembles of lattice\ngauge-field configurations generated by the RBC and UKQCD collaborations, and\nperform extrapolations of the form factors to the continuum limit and physical\npion mass. We give Standard-Model predictions for the $\\Lambda_b \\to\n\\Lambda^*(1520)\\ell^+\\ell^-$ differential branching fraction and angular\nobservables in the high-$q^2$ region.",
        "positive": "Non-perturbative renormalization constants and light quark masses: We present the results of an extensive non-perturbative calculation of the\nrenormalization constants of bilinear quark operators for the\nnon-perturbatively O(a)-improved Wilson action. The results are obtained at\nfour values of the lattice coupling, by using the RI/MOM and the Ward\nidentities methods. A new non-perturbative renormalization technique, which is\nbased on the study of the lattice correlation functions at short distance in\nx-space, is also numerically investigated. We then use our non-perturbative\ndetermination of the quark mass renormalization constants to compute the values\nof the strange and the average up/down quark masses. After performing an\nextrapolation to the continuum limit, we obtain ms^msbar(2 GeV) = (106 +- 2 +-\n8) MeV and ml^msbar(2 GeV)=(4.4 +- 0.1 +- 0.4) MeV."
    },
    {
        "anchor": "Some Answered and Unanswered Questions About the Structure of the Set of\n  Fermionic Actions with GWL Symmetry: Several issues related to the question \"How simple can Ginsparg-Wilson\nfermionic actions be?\" are discussed, and it is suggested that simplicity in\nthe eigenspace should be looked for.",
        "positive": "Series expansions for lattice Green functions: Lattice Green functions appear in lattice gauge theories, in lattice models\nof statistical physics and in random walks. Here, space coordinates are treated\nas parameters and series expansions in the mass are obtained. The singular\npoints in arbitrary dimensions are found. For odd dimensions these are branch\npoints with half odd-integer exponents, while for even dimensions they are of\nthe logarithmic type. The differential equations for one, two and three\ndimensions are derived, and the general form for arbitrary dimensions is\nindicated. Explicit series expressions are found in one and two dimensions.\nThese series are hypergeometric functions. In three and higher dimensions the\nseries are more complicated. Finally an algorithmic method by Vohwinkel,\nLuscher and Weisz is shown to generalize to arbitrary anisotropies and mass."
    },
    {
        "anchor": "High-loop perturbative renormalization constants for Lattice QCD (II):\n  three-loop quark currents for tree-level Symanzik improved gauge action and\n  n_f=2 Wilson fermions: Numerical Stochastic Perturbation Theory was able to get three- (and even\nfour-) loop results for finite Lattice QCD renormalization constants. More\nrecently, a conceptual and technical framework has been devised to tame finite\nsize effects, which had been reported to be significant for (logarithmically)\ndivergent renormalization constants. In this work we present three-loop results\nfor fermion bilinears in the Lattice QCD regularization defined by tree-level\nSymanzik improved gauge action and n_f=2 Wilson fermions. We discuss both\nfinite and divergent renormalization constants in the RI'-MOM scheme. Since\nrenormalization conditions are defined in the chiral limit, our results also\napply to Twisted Mass QCD, for which non-perturbative computations of the same\nquantities are available. We emphasize the importance of carefully accounting\nfor both finite lattice space and finite volume effects. In our opinion the\nlatter have in general not attracted the attention they would deserve.",
        "positive": "Curvature of the critical line on the plane of quark chemical potential\n  and pseudo scalar meson mass for three-flavor QCD: We investigate the phase structure of three-flavor QCD in the presence of\nfinite quark chemical potential $\\mu/T\\lesssim1.2$ by using the\nnon-perturbatively $O(a)$ improved Wilson fermion action on lattices with a\nfixed temporal extent $N_{\\rm t}=6$ and varied spatial linear extents $N_{\\rm\ns}=8,10,12$. Especially, we focus on locating the critical end point that\ncharacterizes the phase structure, and extracting the curvature of the critical\nline on the $\\mu$-$m_{\\pi}$ plane. For Wilson-type fermions, the correspondence\nbetween bare parameters and physical parameters is indirect. Hence we present a\nstrategy to transfer the bare parameter phase structure to the physical one, in\norder to obtain the curvature. Our conclusion is that the curvature is\npositive. This implies that, if one starts from a quark mass in the region of\ncrossover at zero chemical potential, one would encounter a first-order phase\ntransition when one raises the chemical potential."
    },
    {
        "anchor": "Mellin moments of spin dependent and independent PDFs of the pion and\n  rho meson: We compute the second moments of pion and rho parton distribution functions\n(PDFs) in lattice QCD with $N_f = 2+1$ flavors of improved Wilson fermions. We\ndetermine both singlet and non-singlet flavor combinations and, for the first\ntime, take disconnected contributions fully into account. In the case of the\nrho, we also calculate the additional contribution arising from the $b_1$\nstructure function. The numerical analysis includes 26 ensembles, mainly\ngenerated by the CLS effort, with pion masses ranging from 420MeV down to\n214MeV and with 5 different lattice spacings in the range of 0.1fm to 0.05fm.\nThis enables us to take the continuum limit, as well as to resolve the quark\nmass dependencies reliably. Additionally we discuss the contaminations of rho\ncorrelation functions by two-pion states.",
        "positive": "A Framework for Systematic Study of QCD Vacuum Structure I: Kolmogorov\n  Entropy and the Principle of Chiral Ordering: In this series of articles we describe a systematic approach to studying QCD\nvacuum structure using the methods of lattice gauge theory. Our framework\nincorporates four major components. (i) The recently established existence of\nspace-time order at all scales (fundamental structure) observed directly in\ntypical configurations of regularized path-integral ensembles. (ii) The notion\nof scale-dependent vacuum structure (effective structure) providing the means\nfor representing and quantifying the influence of fluctuations at various\nscales on physical observables (phenomena). (iii) The unified description of\ngauge and fermionic aspects of the theory which facilitates a high level of\nspace-time order in the path-integral ensembles. (iv) The strict ``Bottom-Up''\napproach wherein the process of identifying the vacuum structure proceeds\ninductively, using the information from valid lattice QCD ensembles as the only\ninput. In this work we first elaborate on the meaning of the notion of\nspace-time order in a given configuration which is conceptually at the heart of\nthe path-integral approach to vacuum structure. It is argued that the\nalgorithmic complexity of binary strings associated with coarse-grained\ndescriptions of the configuration provides a relevant quantitative measure. The\ncorresponding ensemble averages define the ranking of different lattice\ntheories at given cutoff by the degree of space-time order generated via their\ndynamics. We then introduce the set of local transformations of a\nconfiguration, chiral orderings, in which the transformed gauge connection\nrepresents an effective matrix phase acquired by chiral fermion when hopping\nover a given link. It is proposed that chiral orderings facilitate the\nevolution in the set of actions which increases the degree of space-time order\nwhile preserving the physical content of the theory, and should thus be used in\nthe search for the fundamental QCD vacuum structure. The relation to\nrenormalization group ideas is discussed, and the first step in general\nformulation of effective lattice QCD realizing the notion of scale-dependent\nvacuum structure is given."
    },
    {
        "anchor": "Hopping Parameter Expansion for Heavy-Light Systems: We present a technique which permits the calculation of two-point functions\nof operators containing one heavy quark and an arbitrary number of light quarks\nas analytic functions of the heavy-quark mass. It is based on the standard\nJacobi linear solver used for the calculation of quark propagators. Results for\nthe heavy-light pseudoscalar and vector meson masses are obtained on 16^3x48\nlattices at beta = 6.2 using the Wilson fermion action, and agree with\npublished data. The incorporation of smeared operators and $O(a)$-improved\nactions presents no problems.",
        "positive": "Heavy hadrons on $N_f=2$ and $2+1$ improved clover-Wilson lattices: We present the masses of singly ($B$, $B_s$, $\\Lambda_b$, $\\Sigma_b$, etc.),\ndoubly ($B_c$, $\\eta_b$, $\\Upsilon$, $\\Xi_{bc}$, $\\Xi_{bb}$, etc.), and triply\n($\\Omega_{bcc}$, $\\Omega_{bbc}$, $\\Omega_{bbb}$, etc.) heavy hadrons arising\nfrom (QCDSF-UKQCD) lattices with improved clover-Wilson light quarks. For the\nbottom quark, we use an $O(a,v^4)$-improved version of lattice NRQCD. Part of\nthe bottomonia spectrum is used to provide an alternative scale and to\ndetermine the physical quark mass and radiative corrections used in the\nheavy-quark action. Results for spin splittings, opposite parities, and, in\nsome cases, excited states are presented. Higher lying states and baryons with\ntwo light quarks appear to be especially affected by the relatively small\nvolumes of this (initially) initial study. This and other systematics are\nbriefly discussed."
    },
    {
        "anchor": "Static Energy in ($2+1+1$)-Flavor Lattice QCD: Scale Setting and Charm\n  Effects: We present results for the static energy in ($2+1+1$)-flavor QCD over a wide\nrange of lattice spacings and several quark masses, including the physical\nquark mass, with ensembles of lattice-gauge-field configurations made available\nby the MILC Collaboration. We obtain results for the static energy out to\ndistances of nearly $1$~fm, allowing us to perform a simultaneous determination\nof the scales $r_{1}$ and $r_{0}$, as well as the string tension $\\sigma$. For\nthe smallest three lattice spacings we also determine the scale $r_{2}$. Our\nresults for $r_{0}/r_{1}$ and $r_{0}\\sqrt{\\sigma}$ agree with published\n($2+1$)-flavor results. However, our result for $r_{1}/r_{2}$ differs\nsignificantly from the value obtained in the ($2+1$)-flavor case, which is most\nlikely due to the effect of the charm quark. We also report results for\n$r_{0}$, $r_{1}$, and $r_{2}$ in~fm, with the former two being slightly lower\nthan published ($2+1$)-flavor results. We study in detail the effect of the\ncharm quark on the static energy by comparing our results on the finest two\nlattices with the previously published ($2+1$)-flavor QCD results at similar\nlattice spacing. We find that for $r > 0.2$~fm our results on the static energy\nagree with the ($2+1$)-flavor result, implying the decoupling of the charm\nquark for these distances. For smaller distances, on the other hand, we find\nthat the effect of the dynamical charm quark is noticeable. The lattice results\nagree well with the two-loop perturbative expression of the static energy\nincorporating finite charm mass effects. This is the first time that the\ndecoupling of the charm quark is observed and quantitatively analyzed on\nlattice data of the static energy.",
        "positive": "Phase Structure of Compact $QED_3$ with Massless Fermions: In the framework of (2+1)-dimensional compact lattice QED with light\nfermions, we investigate the phase diagram in the $(\\beta, N)$ plane. The\napproximations involved are related to an expansion of the effective fermionic\naction as a power series of the flavor number $N$. We also develop a new\nmechanism for understanding the $N-$critical phenomenon in the full theory. Our\nresults for the specific heat indicate that only one phase does exist. We give\nstrong evidences that this qualitative result should not be changed with the\ninclusion of higher order terms in the $N$ expansion."
    },
    {
        "anchor": "Random Matrix Models for the Hermitian Wilson-Dirac operator of QCD-like\n  theories: We introduce Random Matrix Models for the Hermitian Wilson-Dirac operator of\nQCD-like theories. We show that they are equivalent to the $\\epsilon$-limit of\nthe chiral Lagrangian for Wilson chiral perturbation theory. Results are\nobtained for two-color QCD with quarks in the fundamental representation of the\ncolor group as well as any-color QCD with quarks in the adjoint representation.\nFor $N_c=2$ we also have obtained the lattice spacing dependence of the\nquenched average spectral density for a fixed value of the index of the Dirac\noperator. Comparisons with direct numerical simulations of the random matrix\nensemble are shown.",
        "positive": "Implementation of the conjugate gradient algorithm on FPGA devices: Results of porting parts of the Lattice Quantum Chromodynamics code to modern\nFPGA devices are presented. A single-node, double precision implementation of\nthe Conjugate Gradient algorithm is used to invert numerically the Dirac-Wilson\noperator on a 4-dimensional grid on a Xilinx Zynq evaluation board. The code is\ndivided into two software/hardware parts in such a way that the entire\nmultiplication by the Dirac operator is performed in programmable logic, and\nthe rest of the algorithm runs on the ARM cores. Optimized data blocks are used\nto efficiently use data movement infrastructure allowing to reach intervals of\n1 clock cycle. We show that the FPGA implementation can offer a comparable\nperformance compared to that obtained using Intel Xeon Phi KNL."
    },
    {
        "anchor": "Unitarity Bounds for Semileptonic Decays in Lattice QCD: In this work we discuss in detail the non-perturbative determination of the\nmomentum dependence of the form factors entering in semileptonic decays using\nunitarity and analyticity constraints. The method contains several new elements\nwith respect to previous proposals and allows to extract, using suitable\ntwo-point functions computed non-perturbatively, the form factors at low\nmomentum transfer $q^2$ from those computed explicitly on the lattice at large\n$q^2$, without any assumption about their $q^2$-dependence. The approach will\nbe very useful for exclusive semileptonic $B$-meson decays, where the direct\ncalculation of the form factors at low $q^2$ is particularly difficult due to\nlarge statistical fluctuations and discretisation effects. As a testing ground\nwe apply our approach to the semileptonic $D \\to K \\ell \\nu_\\ell$ decay, where\nwe can compare the results of the unitarity approach to the explicit direct\nlattice calculation of the form factors in the full $q^2$-range. We show that\nthe method is very effective and that it allows to compute the form factors\nwith rather good precision.",
        "positive": "Fluctuation Induced First Order Phase Transitions: We study a $U(N)\\times U(N)$ symmetric scalar field model in four and three\ndimensions. First, using our data in four dimensions in the weak coupling\nregion, we demonstrate explicitly that the observed first order phase\ntransition is induced by quantum fluctuations. Next, based on the\nrenormalization group and our new simulation results in three dimensions we\nargue that even if the $U_A(1)$ symmetry is restored below the critical\ntemperature the QCD finite temperature chiral phase transition for two flavor\ncould be extremely weak first order. Contribution to Lattice '93 proceedings.\nNeeds espcrc2.sty file (included). Search Figure1.ps, Figure2.ps, ... for\npostscript files."
    },
    {
        "anchor": "Free energy of the self-interacting relativistic lattice Bose gas at\n  finite density: The density of state approach has recently been proposed as a potential route\nto circumvent the sign problem in systems at finite density. In this study,\nusing the Linear Logarithmic Relaxation (LLR) algorithm, we extract the\ngeneralised density of states, which is defined in terms of the imaginary part\nof the action, for the self-interacting relativistic lattice Bose gas at finite\ndensity. After discussing the implementation and testing the reliability of our\napproach, we focus on the determination of the free energy difference between\nthe full system and its phase-quenched counterpart. Using a set of lattices\nranging from $4^4$ to $16^4$ , we show that in the low density phase, this\noverlap free energy can be reliably extrapolated to the thermodynamic limit.\nThe numerical precision we obtain with the LLR method allows us to determine\nwith sufficient accuracy the expectation value of the phase factor, which is\nused in the calculation of the overlap free energy, down to values of ${\\cal\nO}(10^{-480})$. When phase factor measurements are extended to the dense phase,\na change of behaviour of the overlap free energy is clearly visible as the\nchemical potential crosses a critical value. Using fits inspired by the\napproximate validity of mean-field theory, which is confirmed by our\nsimulations, we extract the critical chemical potential as the non-analyticity\npoint in the overlap free energy, obtaining a value that is in agreement with\nother determinations. Implications of our findings and potential improvements\nof our methodology are also discussed.",
        "positive": "Magnetic and electric screening masses from Polyakov-loop correlations: Screening properties of the quark gluon plasma are studied from Polyakov-loop\ncorrelation in lattice QCD simulations with two flavors of improved Wilson\nquarks at temperatures $T/\\Tpc \\simeq 1$--4 where $\\Tpc$ is the pseudocritical\ntemperature. Using the Euclidean-time reflection symmetry and the charge\nconjugation symmetry, we introduce various types of Polyakov-loop correlation\nfunctions and extract screening masses in magnetic and electric sectors. We\nfind that the temperature dependence of the screening masses are well described\nby the weak coupling expansion. We also find that a ratio of the screening\nmasses in the electric sector to the magnetic sector shows qualitative\nagreement with a prediction from the dimensionally-reduced effective field\ntheory and the N=4 supersymmetric Yang-Mills theory at $1.3 < T/\\Tpc < 3$."
    },
    {
        "anchor": "Fractality and other properties of center domains at finite temperature\n  Part 1: SU(3) lattice gauge theory: Using finite temperature SU(3) lattice gauge theory in the fixed scale\napproach we analyze center properties of the local Polyakov loop L(x). We\nconstruct spatial clusters of points x where the phase of L(x) is near the same\ncenter element and study their properties as a function of temperature. We find\nthat below the deconfinement transition the clusters form objects with a\nfractal dimension D < 3. As the temperature is increased, the largest cluster\nstarts to percolate and its dimensionality approaches D=3. The fractal\nstructure of the clusters in the transition region may have implications\nregarding both the small shear viscosity and the large opacity of the Quark\nGluon Plasma observed in heavy-ion collision experiments.",
        "positive": "Vacuum correlators at short distances from lattice QCD: We propose a method to help control cutoff effects in the short-distance\ncontribution to integrated correlation functions, such as the hadronic vacuum\npolarization (HVP), using the corresponding screening correlators computed at\nfinite temperature. The strategy is investigated with Wilson fermions at\nleading order, which reveals a logarithmically-enhanced lattice artifact in the\nshort-distance contribution, whose coefficient is determined at this order. We\nthen perform a numerical study with $N_\\mathrm{f}=2$ O($a$)-improved Wilson\nfermions and a temperature $T\\approx250~\\mathrm{MeV}$, with lattice spacings\ndown to $a\\approx0.03~\\mathrm{fm}$, which suggests good control can be achieved\non the short-distance contribution to the HVP and the Adler function at large\nvirtuality. Finally, we put forward a scheme to compute the complete HVP\nfunction at arbitrarily large virtualities using a step-scaling in the\ntemperature."
    },
    {
        "anchor": "Low-energy Scattering of $(D\\bar{D}^{*})^\\pm$ System And the\n  Resonance-like Structure $Z_c(3900)$: In this exploratory lattice study, low-energy scattering of the\n$(D\\bar{D}^{*})^\\pm$ meson system is analyzed using lattice QCD with $N_f=2$\ntwisted mass fermion configurations with three pion mass values. The\ncalculation is performed within single-channel L\\\"uscher's finite-size\nformalism. The threshold scattering parameters, namely the scattering length\n$a_0$ and the effective range $r_0$, for the $s$-wave scattering in $J^P=1^+$\nchannel are extracted. For the cases in our study, the interaction between the\ntwo charmed mesons is weakly repulsive. Our lattice results therefore do not\nsupport the possibility of a shallow bound state for the two mesons for the\npion mass values we studied. This calculation provides some useful information\non the nature of the newly discovered resonance-like structure $Z_c(3900)$ by\nvarious experimental groups.",
        "positive": "Three-quark systems in MA and MC projected QCD: We study three quark systems in Maximally Abelian (MA) and Maximal Center\n(MC) projected QCD on quenched SU(3) lattice, and also in the monopole/photon\npart, where only the color-electric/magnetic current exists, using the Hodge\ndecomposition. First, we perform the quantitative study of the three-quark (3Q)\npotential V_{3Q} and the string tension \\sigma_{3Q} in baryons. For MA\nprojected QCD, the monopole part and MC projected QCD, we find that the\nconfinement potential in V_{3Q} obeys the Y-Ansatz and the string tension\n\\sigma_{3Q} is approximately equal to that in SU(3) QCD. The universality of\nthe string tension, \\sigma_{3Q} \\simeq \\sigma_{Q\\bar Q}, is also found between\nthe 3Q and the Q\\bar Q potentials. We find a strong similarity of the\ninter-quark potential between the monopole part and MC projected QCD. In\ncontrast, almost no confinement force is found in the inter-quark potential in\nthe photon part. Next, we study the spectrum of light hadrons in MA projected\nQCD and the monopole/photon part, paying attention to the N-\\Delta mass\nsplitting. We find that the N-\\Delta mass splitting is significantly reduced in\nMA projected QCD and the monopole part, where the one-gluon-exchange effect or\nthe Coulomb-potential part is largely reduced due to the Abelianization or the\nHodge decomposition. This fact seems to indicate that the main origin of the\nmass splitting is one-gluon exchange."
    },
    {
        "anchor": "Leading order hadronic contribution to g-2 from twisted mass QCD: We calculate the leading order hadronic contribution to the muon anomalous\nmagnetic moment using twisted mass lattice QCD. The pion masses range from 330\nMeV to 650 MeV. We use two lattice spacings, a=0.079 fm and 0.063 fm, to study\nlattice artifacts. Finite-size effects are studied for two values of the pion\nmass, and we calculate the disconnected contributions for four ensembles.\nParticular attention is paid to the dominant contributions of the vector\nmesons, both phenomenologically and from our lattice calculation.",
        "positive": "Predicting the singlet vector channel in a partially Higgsed gauge\n  theory: We study a toy version of a grand-unified theory on the lattice: An $SU(3)$\ngauge theory, which experiences a Brout-Englert-Higgs effect due to a single\nHiggs field in the fundamental representation. This yields a perturbative\nbreaking pattern $SU(3) \\rightarrow SU(2)$. We investigate the singlet vector\nchannel, finding an apparently non-degenerate and massive ground state. This is\nin contradistinction to the perturbative prediction of three massless and five\nmassive vector states, even though the correlation functions of the gauge\nbosons exhibit a weak-coupling behavior, being almost tree-level-like. However,\na combination of perturbation theory with the Fr\\\"ohlich-Morchio-Strocchi\nmechanism allows to predict the physical spectrum in this channel."
    },
    {
        "anchor": "A test of Taylor- and modified Taylor-expansion: We compare Taylor expansion and a modified variant of Taylor expansion, which\nincorporates features of the fugacity series, for expansions in the chemical\npotential around a zero-density lattice field theory. As a first test we apply\nboth series to the cases of free fermions and free bosons. Convergence and\nother properties are analyzed.",
        "positive": "From Spectroscopy to the Strong Coupling Constant with Heavy Wilson\n  Quarks: In this work we present lattice calculations of the masses of P-wave mesons\nusing Monte Carlo simulations. Our valence fermions are defined by the Wilson\naction. Our gauge fields are generated with both dynamical staggered fermions\nat a lattice coupling $\\beta\\equiv 6/g^2=5.6$ for sea quark masses of\n$am_q=0.010$ and 0.025, and in the quenched approximation at $\\beta=6.0$. We\npresent results for charm and charmonium spectroscopy and use them to compute\nthe strong coupling constant $\\alpha_s$. We compare our results to those of\nother recent lattice calculations and experiments."
    },
    {
        "anchor": "Thermodynamics with 3 and 2+1 Flavors of Improved Staggered Quarks: We present preliminary results from exploring the phase diagram of finite\ntemperature QCD with three degenerate flavors and with two light flavors and\nthe mass of the third held approximately at the strange quark mass. We use an\norder $\\alpha_s^2 a^2, a^4$ Symanzik improved gauge action and an order\n$\\alpha_s a^2, a^4$ improved staggered quark action. The improved staggered\naction leads to a dispersion relation with diminished lattice artifacts, and\nhence better thermodynamic properties. It decreases the flavor symmetry\nbreaking of staggered quarks substantially, and we estimate that at the\ntransition temperature for an $N_t=8$ to $N_t=10$ lattice {\\em all} pions will\nbe lighter than the lightest kaon. Preliminary results on lattices with\n$N_t=4$, 6 and 8 are presented.",
        "positive": "Lattice artefacts in the Schr\u00f6dinger Functional coupling for strongly\n  interacting theories: Models of Dynamical Electroweak Symmetry Breaking are expected to display a\nquasi-conformal scaling behaviour in order to accommodate experimental\nconstraints. The scaling properties of a theory can be studied using finite\nvolume renormalisation schemes. Among these, the most practical ones are based\non the Schr\\\"odinger Functional (SF). However, lattices accessible in nu-\nmerical simulations suffer from potentially large cutoff effects and special\ncare has to be taken to remove these effects. Here we will study the standard\nsetup of the SF with Wilson quarks and a setup with chirally rotated boundary\nconditions. We study the step scaling function for SU(2) and SU(3) gauge groups\nin the fundamental, 2-index symmetric and adjoint representations. We per- form\nthe O(a)-improvement of both setups to 1-loop order in perturbation theory, and\nwe describe a way of minimising higher order cutoff effects by a redefinition\nof the renormalised coupling."
    },
    {
        "anchor": "Hadronic light-by-light scattering contribution to the muon $g-2$ from\n  lattice QCD: semi-analytical calculation of the QED kernel: Hadronic light-by-light scattering is one of the virtual processes that\ncauses the gyromagnetic factor $g$ of the muon to deviate from the value of two\npredicted by Dirac's theory. This process makes one of the largest\ncontributions to the uncertainty of the Standard Model prediction for the muon\n$(g-2)$. Lattice QCD allows for a first-principles approach to computing this\nnon-perturbative effect. In order to avoid power-law finite-size artifacts\ngenerated by virtual photons in lattice simulations, we follow a\ncoordinate-space approach involving a weighted integral over the vertices of\nthe QCD four-point function of the electromagnetic current carried by the\nquarks. Here we present in detail the semi-analytical calculation of the QED\npart of the amplitude, employing position-space perturbation theory in\ncontinuous, infinite four-dimensional Euclidean space. We also provide some\nuseful information about a computer code for the numerical implementation of\nour approach that has been made public at https://github.com/RJHudspith/KQED.",
        "positive": "On the spectrum of closed k=2 flux tubes in D=2+1 SU(N) gauge theories: We calculate the energy spectrum of a k=2 flux tube that is closed around a\nspatial torus, as a function of its length l. We do so for SU(4) and SU(5)\ngauge theories in 2 space dimensions. We find that to a very good approximation\nthe eigenstates belong to the irreducible representations of the SU(N) group\nrather than just to its center, Z_N. We obtain convincing evidence that the\nlow-lying states are, for l not too small, very close to those of the\nNambu-Goto free string theory (in flat space-time). The correction terms appear\nto be typically of O(1) in appropriate units, much as one would expect if the\nbosonic string model were an effective string theory for the dynamics of these\nflux tubes. This is in marked contrast to the case of fundamental flux tubes\nwhere such corrections have been found to be unnaturally small. Moreover we\nfind that these corrections appear to be particularly small when the `phonons'\nalong the string have the same momentum, and large when their momentum is\nopposite. This provides information about the detailed nature of the\ninteractions in the effective string theory. We have searched for, but not\nfound, extra states that would arise from the excitation of the massive modes\npresumably associated with the non-trivial structure of the flux tube."
    },
    {
        "anchor": "Chiral Symmetry and the Residual Mass in Lattice QCD with the Optimal\n  Domain-Wall Fermion: We derive the axial Ward identity for lattice QCD with domain-wall fermions,\nand from which we obtain a formula for the residual mass (45)-(46), that can be\nused to measure the chiral symmetry breaking due to the finite extension Ns in\nthe fifth dimension. Furthermore, we obtain an upper bound for the residual\nmass in lattice QCD with the optimal domain-wall fermion.",
        "positive": "Momentum space topology in the lattice gauge theory: Momentum space topology of relativistic gauge theory is considered. The\ntopological invariants in momentum space are introduced for the case, when\nthere is the mass gap while the fermion Green functions admit zeros. The index\ntheorem is formulated that relates the number of massless particles and\ngeneralized unparticles at the phase transitions to the jumps of the\ntopological invariants. The pattern is illustrated by the lattice model with\noverlap fermions."
    },
    {
        "anchor": "$N_f=2+1+1$ renormalisation of four-quark operators: When several four-quark operators are allowed to mix through renormalisation,\nthis can considerably amplify the problems coming from perturbative truncation\nand discretisation effects. In this work we investigate whether our previous\n$B_K$ strategy can conveniently be generalised to a wider set of operators,\ncorresponding to the so-called \"SUSY $B_K$\" basis of four-quark operators. We\nshow that the discretisation effects, when plotted as a function of $ap$, are\nsurprisingly independent of the lattice spacing. They appear reasonably under\ncontrol up to very large energy scales. This allows us to discuss the effect of\nvarying the intermediate scale on which the perturbative matching is done, and\ntherefore the prospects of future high-precision studies with a\nRome-Southampton renormalisation.",
        "positive": "Deflated BiCGStab for linear equations in QCD problems: The large systems of complex linear equations that are generated in QCD\nproblems often have multiple right-hand sides (for multiple sources) and\nmultiple shifts (for multiple masses). Deflated GMRES methods have previously\nbeen developed for solving multiple right-hand sides. Eigenvectors are\ngenerated during solution of the first right-hand side and used to speed up\nconvergence for the other right-hand sides. Here we discuss deflating\nnon-restarted methods such as BiCGStab. For effective deflation, both left and\nright eigenvectors are needed. Fortunately, with the Wilson matrix, left\neigenvectors can be derived from the right eigenvectors. We demonstrate for\ndifficult problems with kappa near kappa_c that deflating eigenvalues can\nsignificantly improve BiCGStab. We also will look at improving solution of\ntwisted mass problems with multiple shifts. Projecting over previous solutions\nis an easy way to reduce the work needed."
    },
    {
        "anchor": "Axial Anomaly in Lattice Abelian Gauge Theory in Arbitrary Dimensions: Axial anomaly of lattice abelian gauge theory in hyper-cubic regular lattice\nin arbitrary even dimensions is investigated by applying the method of exterior\ndifferential calculus. The topological invariance, gauge invariance and\nlocality of the axial anomaly determine the explicit form of the topological\npart. The anomaly is obtained up to a multiplicative constant for finite\nlattice spacing and can be interpreted as the Chern character of the abelian\nlattice gauge theory.",
        "positive": "Improved Nonrelativistic QCD for Heavy Quark Physics: We construct an improved version of nonrelativistic QCD for use in lattice\nsimulations of heavy quark physics, with the goal of reducing systematic errors\nfrom all sources to below 10\\%. We develop power counting rules to assess the\nimportance of the various operators in the action and compute all leading order\ncorrections required by relativity and finite lattice spacing. We discuss\nradiative corrections to tree level coupling constants, presenting a procedure\nthat effectively resums the largest such corrections to all orders in\nperturbation theory. Finally, we comment on the size of nonperturbative\ncontributions to the coupling constants."
    },
    {
        "anchor": "O(a) improved twisted mass lattice QCD: Lattice QCD with Wilson quarks and a chirally twisted mass term (tmQCD) has\nbeen introduced in refs. [1,2]. We here apply Symanzik's improvement programme\nto this theory and list the counterterms which arise at first order in the\nlattice spacing a. Based on the generalised transfer matrix, we define the\ntmQCD Schrodinger functional and use it to derive renormalized on-shell\ncorrelation functions. By studying their continuum approach in perturbation\ntheory we then determine the new O(a) counterterms of the action and of a few\nquark bilinear operators to one-loop order.",
        "positive": "Pion and Kaon Distribution Amplitudes from lattice QCD: towards the\n  continuum limit: We present the current status of a non-perturbative lattice calculation of\nthe moments of the pion and kaon distribution amplitudes by the RQCD\ncollaboration. Our investigation is carried out using $N_f=2+1$ dynamical,\nnon-perturbatively O(a)-improved Wilson fermions on the CLS ensembles with 5\ndifferent lattice spacings and pion masses down to the physical pion mass. A\ncombined continuum and chiral extrapolation to the physical point is performed\nalong two independent quark mass trajectories simultaneously. We employ\nmomentum smearing in order to decrease the contamination by excited states and\nincrease statistical precision."
    },
    {
        "anchor": "Neutral B Mixing in Staggered Chiral Perturbation Theory: I calculate, at one loop in staggered chiral perturbation theory, the matrix\nelements of the complete set of five local operators that may contribute to B\nmixing both in the Standard Model and in beyond-the-Standard-Model theories.\nLattice computations of these matrix elements by the Fermilab Lattice/MILC\ncollaborations (and earlier by the HPQCD collaboration) convert a light\nstaggered quark into a naive quark, and construct the relevant 4-quark\noperators as local products of two local bilinears, each involving the naive\nlight quark and the heavy quark. This particular representation of the\noperators turns out to be important in the chiral calculation, and it results\nin the presence of \"wrong-spin\" operators, whose contributions however vanish\nin the continuum limit. If the matrix elements of all five operators are\ncomputed on the lattice, then no additional low energy constants are required\nto describe wrong-spin chiral effects.",
        "positive": "QCD Critical Point and Complex Chemical Potential Singularities: The thermodynamic singularities of QCD in the plane of complex baryo-chemical\npotential mu are studied. Predictions are made using scaling and universality\narguments in the vicinity of the massless quark limit. The results are\nillustrated by a calculation of complex mu singularities in a random matrix\nmodel at finite temperature. Implications for lattice QCD simulations aimed at\nlocating the QCD critical point are discussed."
    },
    {
        "anchor": "High statistics study of in-medium S- and P-wave quarkonium states in\n  lattice Non-relativistic QCD: Many measurements of quarkonium suppression at the LHC, e.g. the nuclear\nmodification factor $R_{AA}$ of $J/\\Psi$, are well described by a multitude of\ndifferent models. Thus pinpointing the underlying physics aspects is difficult\nand guidance based on first principles is needed. Here we present the current\nstatus of our ongoing high precision study of in-medium spectral properties of\nboth bottomonium and charmonium based on NRQCD on the lattice. This effective\nfield theory allows us to capture the physics of quarkonium without modeling\nassumptions in a thermal QCD medium. In our study a first principles and\nrealistic description of the QCD medium is provided by state-of-the-art\nlattices of the HotQCD collaboration at almost physical pion mass. Our updated\nresults corroborate a picture of sequential modification of states with respect\nto their vacuum binding energy. Using a novel low-gain variant of the Bayesian\nBR method for reconstructing spectral functions we find that remnant features\nof the Upsilon may survive up to $T\\sim400$MeV, while the $\\chi_b$ signal\ndisappears around $T\\sim270$MeV. The $c\\bar{c}$ analysis hints at melting of\n$\\chi_c$ below $T\\sim190$MeV while some $J/\\Psi$ remnant feature might survive\nup to $T\\sim245$MeV. An improved understanding of the numerical artifacts in\nthe Bayesian approach and the availability of increased statistics have made\npossible a first quantitative study of the in-medium ground state masses, which\ntend to lower values as $T$ increases, consistent with lattice potential based\nstudies.",
        "positive": "Gauge and Higgs Boson Masses from an Extra Dimension: We present novel calculations of the mass hierarchy of the $SU(2)$ pure gauge\ntheory on a space-time lattice with an orbifolded fifth dimension. This theory\nhas three parameters; the gauge coupling $\\beta$, the anisotropy $\\gamma$,\nwhich is a measure of the ratio of the lattice spacing in the four dimensions\nto that in the fifth dimension, and the extent of the extra dimension $N_{5}$.\nUsing a large basis of scalar and vector operators we explore in detail the\nspectrum along the $\\gamma = 1$ line, and for the first time we investigate the\nspectrum for $\\gamma \\neq 1$."
    },
    {
        "anchor": "Setting the scale for the CLS $2 + 1$ flavor ensembles: We present measurements of a combination of the decay constants of the light\npseudoscalar mesons and the gradient flow scale $t_0$, which allow to set the\nscale of the lattices generated by CLS with $2 + 1$ flavors of\nnon-perturbatively improved Wilson fermions. Mistunings of the quark masses are\ncorrected for by measuring the derivatives of observables with respect to the\nbare quark masses.",
        "positive": "On the Extraction of Low-energy Constants of Single- and Double-$\u03b2$\n  Decays from Lattice QCD: A Sensitivity Analysis: Lattice quantum chromodynamics (LQCD) has the promise of constraining\nlow-energy constants (LECs) of nuclear effective field theories (EFTs) from\nfirst-principles calculations that incorporate the dynamics of quarks and\ngluons. Given the Euclidean and finite-volume nature of LQCD outputs, complex\nmappings are developed in recent years to obtain the Minkowski and\ninfinite-volume counterparts of LQCD observables. In particular, as LQCD is\nmoving toward computing a set of important few-nucleon matrix elements at the\nphysical values of the quark masses, it is important to investigate whether the\nanticipated precision of LQCD spectra and matrix elements will be sufficient to\nguarantee tighter constraints on the relevant LECs than those already obtained\nfrom phenomenology, considering the non-trivial mappings involved. With a focus\non the leading-order LECs of the pionless EFT, $L_{1,A}$ and $g_{\\nu}^{NN}$,\nwhich parametrize, respectively, the strength of the isovector axial two-body\ncurrent in a single-$\\beta$ decay (and other related processes such $pp$\nfusion), and of the isotensor contact two-body operator in the neutrinoless\ndouble-$\\beta$ decay within the light neutrino exchange scenario, the expected\nuncertainty on future extractions of $L_{1,A}$ and $g_{\\nu}^{NN}$ are examined\nusing synthetic data at the physical values of the quark masses. It is observed\nthat achieving small uncertainties in $L_{1,A}$ will be challenging, and\n(sub)percent-level precision in the two-nucleon spectra and matrix elements is\nessential in reducing the uncertainty on this LEC compared to the existing\nconstraints. On the other hand, the short-distance coupling of the neutrinoless\ndouble-$\\beta$ decay, $g_{\\nu}^{NN}$, is shown to be less sensitive to\nuncertainties on both LQCD energies and the matrix element, and can likely be\nconstrained with percent-level precision in the upcoming LQCD calculations."
    },
    {
        "anchor": "Dynamical Flavour Symmetry Breaking by a Magnetic Field in Lattice QED_3: We perform a lattice study, in the quenched approximation, of dynamical mass\ngeneration in a system of relativistic (Dirac) fermions, coupled to an Abelian\ngauge field in (2+1)-dimensions, in the presence of an external (constant)\nmagnetic field, perpendicular to the spatial planes. It is shown that a strong\nmagnetic field catalyzes chiral symmetry breaking, in agreement with results in\nthe continuum. The r\\^ole of the higher-Landau poles in inducing a critical\ntemperature above which the phenomenon disappears is pointed out. We also\ndiscuss the implications of this model on the opening of a gap in doped\nantiferromagnetic superconductors.",
        "positive": "Exploring QCD at small sea quark masses with improved Wilson-type quarks: We explore the region of small sea quark masses below $m_{PS}/m_V=0.5$ in\ntwo-flavor QCD using a mean-field improved clover quark action and an\nRG-improved gauge action at $a \\simeq 0.2$ fm on $12^3 \\times 24$ and $16^3\n\\times 24$ lattices. We find that instability of the standard BiCGStab\nalgorithm at small quark masses can be mostly removed by the BiCGStab(DS-$L$)\nalgorithm, which employs $L$-th minimal residual polynomials with a dynamical\nselection of $L$. We also find singular spikes of $\\Delta H$ in the HMC\nalgorithm at moderate values of $\\Delta\\tau$. Nature of the spike is studied.\nWe also study finite-size effects and chiral properties of meson masses."
    },
    {
        "anchor": "Improved Semileptonic Form Factor Calculations in Lattice QCD: We investigate the computational efficiency of two stochastic based\nalternatives to the Sequential Propagator Method used in Lattice QCD\ncalculations of heavy-light semileptonic form factors. In the first method, we\nreplace the sequential propagator, which couples the calculation of two of the\nthree propagators required for the calculation, with a stochastic propagator so\nthat the calculations of all three propagators are independent. This method is\nmore flexible than the Sequential Propagator Method but introduces stochastic\nnoise. We study the noise to determine when this method becomes competitive\nwith the Sequential Propagator Method, and find that for any practical\ncalculation it is competitive with or superior to the Sequential Propagator\nMethod. We also examine a second stochastic method, the so-called ``one-end\ntrick\", concluding it is relatively inefficient in this context. The\ninvestigation is carried out on two gauge field ensembles, using the\nnon-perturbatively improved Wilson-Sheikholeslami-Wohlert action with N_f=2\nmass-degenerate sea quarks. The two ensembles have similar lattice spacings but\ndifferent sea quark masses. We use the first stochastic method to extract\n${\\mathcal O}(a)$-improved, matched lattice results for the semileptonic form\nfactors on the ensemble with lighter sea quarks, extracting f_+(0).",
        "positive": "A recursive approach to determine correlation functions in multi-baryon\n  systems: We propose a recursive algorithm for the calculation of multi-baryon\ncorrelation functions that combines the advantages of a recursive approach with\nthose of the recently proposed unified contraction algorithm. The independent\ncomponents of the correlators are built recursively by adding the baryons one\nafter the other in a given order. The list of nonzero independent components is\nalso constructed in a recursive manner, significantly reducing the resources\nrequired for this step. We computed the number of operations required to\ncalculate the correlators up to Be^8, and observed a significant speedup\ncompared to other techniques. For the calculation of He^4 and Be^8 correlation\nfunctions in the fully relativistic case O(10^8) operations are required,\nwhereas for non-relativistic operators this number can be reduced to e.g.\nO(10^4) in the case of He^4."
    },
    {
        "anchor": "Unexpected results in asymptotically free quantum field theories: We study the behavior of asymptotically free (AF) spin and gauge models when\ntheir continuous symmetry group is replaced by different discrete non-Abelian\nsubgroups. Precise numerical results with relative errors down to O(0.1%)\nsuggest that the models with large subgroups are in the universality class of\nthe underlying original models. We argue that such a scenario is consistent\nwith the known properties of AF theories. The small statistical errors allow a\ndetailed investigation of the cut-off effects also. At least up to correlation\nlengths ~300 they follow effectively an O(a) rather than the expected O(a^2)\nform both in the O(3) and in the dodecahedron model.",
        "positive": "Phase Diagram of the Dirac Spectrum at Nonzero Chemical Potential: The Dirac spectrum of QCD with dynamical fermions at nonzero chemical\npotential is characterized by three regions, a region with a constant\neigenvalue density, a region where the eigenvalue density shows oscillations\nthat grow exponentially with the volume and the remainder of the complex plane\nwhere the eigenvalue density is zero. In this paper we derive the phase diagram\nof the Dirac spectrum from a chiral Lagrangian. We show that the constant\neigenvalue density corresponds to a pion condensed phase while the strongly\noscillating region is given by a kaon condensed phase. The normal phase with\nnonzero chiral condensate but vanishing Bose condensates coincides with the\nregion of the complex plane where there are no eigenvalues."
    },
    {
        "anchor": "Wilson chiral perturbation theory for dynamical twisted mass fermions vs\n  lattice data - a case study: We compute the low lying eigenvalues of the Hermitian Dirac operator in\nlattice QCD with $N_{\\rm f} = 2+1+1$ twisted mass fermions. We discuss whether\nthese eigenvalues are in the $\\epsilon$-regime or the $p$-regime of Wilson\nchiral perturbation theory ($\\chi$PT) for twisted mass fermions. Reaching the\ndeep $\\epsilon$-regime is practically unfeasible with presently typical\nsimulation parameters, but still the few lowest eigenvalues of the employed\nensemble evince some characteristic $\\epsilon$-regime features. With this\nconclusion in mind, we develop a fitting strategy to extract two low energy\nconstants from analytical $\\epsilon$-regime predictions at a fixed index. Thus,\nwe obtain results for the chiral condensate and the low energy constant $W_8$.\nWe also discuss how to improve both the theoretical calculation and the lattice\ncomputation.",
        "positive": "HQET at order 1/m: I. Non-perturbative parameters in the quenched\n  approximation: We determine non-perturbatively the parameters of the lattice HQET Lagrangian\nand those of the time component of the heavy-light axial-vector current in the\nquenched approximation. The HQET expansion includes terms of order 1/m. Our\nresults allow to compute, for example, the heavy-light spectrum and B-meson\ndecay constants in the static approximation and to order 1/m in HQET. The\ndetermination of the parameters is separated into universal and non-universal\nparts. The universal results can be used to determine the parameters for\nvarious discretizations. The computation reported in this paper uses the\nplaquette gauge action and the \"HYP1/2\" action for the b-quark described by\nHQET. The parameters of the current also depend on the light-quark action, for\nwhich we choose non-perturbatively O(a)-improved Wilson fermions."
    },
    {
        "anchor": "Constituent Quarks, Diquarks and the N-Delta Mass Splitting: We analyze hadron as well as quark and diquark correlation functions in\nLandau gauge in order to extract information on the spin dependence of the\nquark-quark interaction. We find evidence that the N-Delta mass splitting can\nbe attributed to the spin dependence of the interaction between quarks in a\ncolour anti-triplet state with spin 0 and 1, respectively. The lightest\nexcitations are observed in the S=0 channel. However, no evidence for a deeply\nbound diquark state is found.",
        "positive": "Deconfinement transition line with the Complex Langevin equation up to\n  $\u03bc/T \\sim 5$: We study the deconfinement transition line in QCD for quark chemical\npotentials up to $\\mu_q \\sim 5 T$ ($\\mu_B \\sim 15 T$). To circumvent the sign\nproblem we use the complex Langevin equation with gauge cooling. The plaquette\ngauge action is used with two flavors of naive Wilson fermions at a relatively\nheavy pion mass of roughly 1.3 GeV. A quadratic dependence describes the\ntransition line well on the whole chemical potential range."
    },
    {
        "anchor": "U(1) Gauge Theory with Villain Action on Spherical Lattices: We have studied the U(1) gauge field theory with Villain (periodic Gaussian)\naction on spherelike lattices. The effective size of the systems studied ranges\nfrom 6 to 16. We do not observe any 2-state signal in the distribution function\nof the plaquette expectation value at the deconfining phase transition. The\nobserved finite-size scaling behavior is consistent with a second order phase\ntransition. The obtained value of the critical exponent is nu =0.366(12) and\nthus neither Gaussian (nu = 0.5) nor discontinuous (nu=0.25) type, indicating a\nnontrivial continuum limit.",
        "positive": "Heavy-light decay constants with three dynamical flavors: We present preliminary results for the heavy-light leptonic decay constants\nin the presence of three light dynamical flavors. We generate dynamical\nconfigurations with improved staggered and gauge actions and analyze them for\nheavy-light physics with tadpole improved clover valence quarks. When the scale\nis set by $m_\\rho$, we find an increase of approximately 23% in $f_B$ with\nthree dynamical flavors over the quenched case. Discretization errors appear to\nbe small (of order 3% or less) in the quenched case but have not yet been\nmeasured in the dynamical case."
    },
    {
        "anchor": "Improved Langevin Methods for Spin Systems: We investigate methods for variance reduction and the elimination of\nsystematic error in a Fourier accelerated Langevin scheme for general spin\nmodels. We present results for the $SU(3)\\times SU(3)/SU(3)$ model in\ntwo-dimensions that are consistent wit h those from multi-grid methods. We\nargue that the timing for the Langevin method makes it comparable to multi-grid\nfor a given level of error.",
        "positive": "On the Meissner effect in SU(2) lattice gauge theory: We investigate the dual superconductor model of color confinement in SU(2)\nlattice gauge theory. We find that the transverse distribution of the\nlongitudinal chromoelectric field between static quarks displays the dual\nMeissner effect. We also give evidence that the problem of color confinement\ncould be approached in the framework of the 't~Hooft's Abelian projection."
    },
    {
        "anchor": "Domain wall filters: We propose using the extra dimension separating the domain walls carrying\nlattice quarks of opposite handedness to gradually filter out the ultraviolet\nfluctuations of the gauge fields that are felt by the fermionic excitations\nliving in the bulk. This generalization of the homogeneous domain wall\nconstruction has some theoretical features that seem nontrivial.",
        "positive": "Numerical study of the $\\mathcal{N}=2$ Landau--Ginzburg model: It is believed that the two-dimensional massless $\\mathcal{N}=2$ Wess--Zumino\nmodel becomes the $\\mathcal{N}=2$ superconformal field theory (SCFT) in the\ninfrared (IR) limit. We examine this theoretical conjecture of the\nLandau--Ginzburg (LG) description of the $\\mathcal{N}=2$ SCFT by numerical\nsimulations on the basis of a supersymmetric-invariant momentum-cutoff\nregularization. We study a single supermultiplet with cubic and quartic\nsuperpotentials. From two-point correlation functions in the IR region, we\nmeasure the scaling dimension and the central charge, which are consistent with\nthe conjectured LG description of the $A_2$ and $A_3$ minimal models,\nrespectively. Our result supports the theoretical conjecture and, at the same\ntime, indicates a possible computational method of correlation functions in the\n$\\mathcal{N}=2$ SCFT from the LG description."
    },
    {
        "anchor": "A non-perturbative mechanism for elementary particle mass generation: Taking inspiration from lattice QCD data, we argue that a finite\nnon-perturbative contribution to the quark mass is generated as a consequence\nof the dynamical phenomenon of spontaneous chiral symmetry breaking, in turn\ntriggered by the explicitly breaking of chiral symmetry induced by the critical\nWilson term in the action. In pure lattice QCD this mass term cannot be\nseparated from the unavoidably associated linearly divergent contribution.\nHowever, if QCD is enlarged to a theory where also a scalar field is present,\ncoupled to an SU(2) doublet of fermions via a Yukawa and a Wilson-like term,\nthen in the phase where the scalar field takes a non-vanishing expectation\nvalue, a dynamically generated and \"naturally\" light fermion mass (numerically\nunrelated to the expectation value of the scalar field) is conjectured to\nemerge at a critical value of the Yukawa coupling where the symmetry of the\nmodel is maximally enhanced. Masses dynamically generated in this way display a\nnatural hierarchy according to which the stronger is the strongest of the\ninteractions the fermion is subjected to the larger is its mass.",
        "positive": "Excited-State Effective Masses in Lattice QCD: We apply black-box methods, i.e. where the performance of the method does not\ndepend upon initial guesses, to extract excited-state energies from\nEuclidean-time hadron correlation functions. In particular, we extend the\nwidely used effective-mass method to incorporate multiple correlation functions\nand produce effective mass estimates for multiple excited states. In general,\nthese excited-state effective masses will be determined by finding the roots of\nsome polynomial. We demonstrate the method using sample lattice data to\ndetermine excited-state energies of the nucleon and compare the results to\nother energy-level finding techniques."
    },
    {
        "anchor": "Sampling Nambu-Goto theory using Normalizing Flows: Effective String Theory (EST) is a non-perturbative framework used to\ndescribe confinement in Yang-Mills theory through the modeling of the\ninterquark potential in terms of vibrating strings. An efficient numerical\nmethod to simulate such theories where analytical studies are challenging is\nstill lacking. However, in recent years a new class of deep generative models\ncalled Normalizing Flows (NFs) has been proposed to sample lattice field\ntheories more efficiently than traditional Monte Carlo methods. In this\ncontribution, we show a proof of concept of the application of NFs to EST\nregularized on the lattice. Namely, we introduce Physics-Informed Stochastic\nNormalizing Flows and we use them to sample the Nambu-Goto string action with\ntwo goals: use the known analytical results of this theory as a benchmark and\ndemonstrate the efficiency of our method in obtaining new results of physical\ninterest and in particular in providing a numerical proof for a conjecture\nregarding the width of the string.",
        "positive": "Anti-Ferromagnetic Condensate in Yang-Mills Theory: SU(2) gauge theory with competing interactions is shown to possess a rich\nphase structure with anti-ferromagnetic vacua. It is argued that the phase\nboundaries persist in the weak coupling limit suggesting the existence of\ndifferent renormalized continuum theories for QCD."
    },
    {
        "anchor": "The Scalar Strange Content of the Nucleon from Lattice QCD: The scalar strange-quark matrix element of the nucleon is computed with\nlattice QCD. A mixed-action scheme is used with domain-wall valence fermions\ncomputed on the staggered MILC sea-quark configurations. The matrix element is\ndetermined by making use of the Feynman-Hellmann theorem which relates this\nstrange matrix element to the change in the nucleon mass with respect to the\nstrange-quark mass. The final result of this calculation is m_s < N | s-bar s|\nN > = 49 +-10 +- 15 MeV and, correspondingly f_s = m_s < N | s-bar s |N > / m_N\n= 0.051 +- 0.011 +- 0.016. Given the lack of a quantitative comparison of this\nphenomenologically important quantity determined from various lattice QCD\ncalculations, we take the opportunity to present such an average. The resulting\nconservative determination is f_s = 0.043 +- 0.011.",
        "positive": "Parton distribution functions from Lattice QCD: We present recent results on the first moments of parton distributions using\ngauge configurations generated with two degenerate flavors of light twisted\nmass quarks with pion mass fixed approximately to its physical value. We also\npresent a first study of the vector parton distribution function using a\ntwisted mass ensemble at pion mass of 373 MeV."
    },
    {
        "anchor": "QCD Strings as Constrained Grassmannian Sigma Model:: We present calculations for the effective action of string world sheet in R3\nand R4 utilizing its correspondence with the constrained Grassmannian sigma\nmodel. Minimal surfaces describe the dynamics of open strings while harmonic\nsurfaces describe that of closed strings. The one-loop effective action for\nthese are calculated with instanton and anti-instanton background, reprsenting\nN-string interactions at the tree level. The effective action is found to be\nthe partition function of a classical modified Coulomb gas in the confining\nphase, with a dynamically generated mass gap.",
        "positive": "New Developments in Lattice QCD: Calculation of Flavor Singlet Nucleon\n  Matrix Elements and Hadron Scattering Lengths: Recent developments in lattice QCD calculation of flavor singlet nucleon\nmatrix elements are reviewed. Substantial sea quark contributions are found in\nthe $\\pi$-$N\\ \\sigma$ term and the quark spin content of the nucleon such that\nthe total magnitude including valence contributions is in reasonable agreement\nwith experiments. Some problems with flavor non-singlet nucleon matrix elements\nare pointed out. Recent work on lattice QCD calculation of hadron scattering\nlength is also discussed."
    },
    {
        "anchor": "High Statistics Analysis using Anisotropic Clover Lattices: (I) Single\n  Hadron Correlation Functions: We present the results of high-statistics calculations of correlation\nfunctions generated with single-baryon interpolating operators on an ensemble\nof dynamical anisotropic gauge-field configurations generated by the Hadron\nSpectrum Collaboration using a tadpole-improved clover fermion action and\nSymanzik-improved gauge action. A total of 292,500 sets of measurements are\nmade using 1194 gauge configurations of size 20^3 x 128 with an anisotropy\nparameter \\xi= b_s/b_t = 3.5, a spatial lattice spacing of b_s=0.1227\\pm 0.0008\nfm, and pion mass of m_\\pi ~ 390 MeV. Ground state baryon masses are extracted\nwith fully quantified uncertainties that are at or below the ~0.2%-level in\nlattice units. The lowest-lying negative-parity states are also extracted\nalbeit with a somewhat lower level of precision. In the case of the nucleon,\nthis negative-parity state is above the N\\pi threshold and, therefore, the\nisospin-1/2 \\pi N s-wave scattering phase-shift can be extracted using\nLuescher's method. The disconnected contributions to this process are included\nindirectly in the gauge-field configurations and do not require additional\ncalculations. The signal-to-noise ratio in the various correlation functions is\nexplored and is found to degrade exponentially faster than naive expectations\non many time-slices. This is due to backward propagating states arising from\nthe anti-periodic boundary conditions imposed on the quark-propagators in the\ntime-direction. We explore how best to distribute computational resources\nbetween configuration generation and propagator measurements in order to\noptimize the extraction of single baryon observables.",
        "positive": "Recent Results from the FASTSUM Collaboration: The FASTSUM Collaboration has developed a comprehensive research programme in\nthermal QCD using 2+1 flavour, anisotropic ensembles. In this talk, we\nsummarise some of our recent results including thermal hadron spectrum\ncalculations using our ``Generation 2L'' ensembles which have pion masses of\n239(1) MeV. These include open charm mesons and charm baryons. We also\nsummarise our work using the Backus Gilbert approach to determining the\nspectral function of the NRQCD bottomonium system. Finally, we review our\ndetermination of the interquark potential in the same system, but using our\n``Generation 2'' ensembles which have heavier pion masses of 384(4) MeV."
    },
    {
        "anchor": "Tensor form factor for the $D \\to \u03c0(K)$ transitions with Twisted Mass\n  fermions: We present a preliminary lattice calculation of the $D \\to \\pi$ and $D \\to K$\ntensor form factors $f_T(q^2)$ as a function of the squared 4-momentum transfer\n$q^2$. ETMC recently computed the vector and scalar form factors $f_+(q^2)$ and\n$f_0(q^2)$ describing $D \\to \\pi(K) \\ell \\nu$ semileptonic decays analyzing the\nvector current and the scalar density. The study of the weak tensor current,\nwhich is directly related to the tensor form factor, completes the set of\nhadronic matrix element regulating the transition between these two\npseudoscalar mesons within and beyond the Standard Model where a non-zero\ntensor coupling is possible. Our analysis is based on the gauge configurations\nproduced by the European Twisted Mass Collaboration with $N_f = 2 + 1 + 1$\nflavors of dynamical quarks. We simulated at three different values of the\nlattice spacing and with pion masses as small as 210 MeV and with the valence\nheavy quark in the mass range from $\\simeq 0.7\\, m_c$ to $\\simeq 1.2\\, m_c$.\nThe matrix element of the tensor current are determined for a plethora of\nkinematical conditions in which parent and child mesons are either moving or at\nrest. As for the vector and scalar form factors, Lorentz symmetry breaking due\nto hypercubic effects is clearly observed in the data. We will present\npreliminary results on the removal of such hypercubic lattice effects.",
        "positive": "The finite-temperature phase structure of lattice QCD with twisted-mass\n  Wilson fermions: We report progress in our exploration of the finite-temperature phase\nstructure of two-flavour lattice QCD with twisted-mass Wilson fermions and a\ntree-level Symanzik-improved gauge action for a temporal lattice size\nN_{\\tau}=8. Extending our investigations to a wider region of parameter space\nwe gain a global view of the rich phase structure. We identify the finite\ntemperature transition/crossover for a non-vanishing twisted-mass parameter in\nthe neighbourhood of the zero-temperature critical line at sufficiently high\n\\beta. Our findings are consistent with Creutz's conjecture of a conical shape\nof the finite temperature transition surface. Comparing with NLO lattice chiral\nperturbation theory we achieve an improved understanding of this shape."
    },
    {
        "anchor": "Rigorous QCD Predictions for Decays of P-Wave Quarkonia: Rigorous QCD predictions for decay rates of the P-wave states of heavy\nquarkonia are presented. They are based on a new factorization theorem which is\nvalid to leading order in the heavy quark velocity and to all orders in the\nrunning coupling constant of QCD. The decay rates for all four P states into\nlight hadronic or electromagnetic final states are expressed in terms of two\nphenomenological parameters, whose coefficients are perturbatively calculable.\nLogarithms of the binding energy encountered in previous perturbative\ncalculations of P-wave decays are factored into a phenomenological parameter\nthat is related to the probability for the heavy quark-antiquark pair to be in\na color-octet S-wave state. Applying these predictions to charmonium, we use\nmeasured decay rates for the $\\chione$ and $\\chitwo$ to predict the decay rates\nof the $\\chizero$ and $h_c$.",
        "positive": "Parallel Tempering in Lattice QCD with O(a)-Improved Wilson Fermions: We present details of our investigation of the Parallel Tempering algorithm.\nWe consider the application of action matching technology to the selection of\nparameters. We then present a simple model of the autocorrelations for a\nparticular parallel tempered system. Finally we present numerical results from\napplying the algorithm to lattice QCD with O(a)-improved dynamical fermions\nwith twin ensemble systems"
    },
    {
        "anchor": "The Three Dimensional Thirring Model for Small N_f: We formulate the three dimensional Thirring model on a spacetime lattice and\nstudy it for various even numbers of fermion flavors N_f by Monte Carlo\nsimulation. We find clear evidence for spontaneous chiral symmetry breaking at\nstrong coupling, contradicting the predictions of the 1/N_f expansion. The\ncritical point appears to correspond to an ultra-violet fixed point of the\nrenormalisation group; a fit to a RG-inspired equation of state in the vicinity\nof the fixed point yields distinct critical exponents for N_f=2 and N_f=4,\nwhile no fit is found for N_f=6, suggesting there is a critical number N_fc<6\nbeyond which no chiral symmetry breaking occurs. The spectrum of the N_f=2\ntheory is studied; the states examined vary sharply but continuously across the\ntransition.",
        "positive": "Lattice inputs for the determination of $|V_{cd}|$ and $|V_{cs}|$ from\n  (semi-)leptonic decays: This paper is a review of recent lattice QCD results for $D$ and $D_s$ meson\nleptonic and semileptonic decays. The theory inputs needed for the\ndetermination of $V_{cd}$ and $V_{cs}$ from experimental results are the meson\ndecay constants (leptonic decays) and the form factors (semileptonic decays).\nIn addition one can compare the shape of the form factors from lattice QCD and\nexperiment, and use the full experimental $q^2$ range (partial decay rates in\n$q^2$ bins) to determine the CKM matrix elements."
    },
    {
        "anchor": "Noncompact Gauge-Invariant Simulations of U(1), SU(2), and SU(3): We have applied a new gauge-invariant, noncompact, Monte Carlo method to\nsimulate the $U(1)$, $SU(2)$, and $SU(3)$ gauge theories on $8^4$ and $12^4$\nlattices. The Creutz ratios of the Wilson loops agree with the exact results\nfor $U(1)$ for $\\beta \\ge 0.5$ apart from a renormalization of the charge. The\n$SU(2)$ and $SU(3)$ Creutz ratios robustly display quark confinement at $\\beta\n= 0.5$ and $\\beta = 2$, respectively. At much weaker coupling, the $SU(2)$ and\n$SU(3)$ Creutz ratios agree with perturbation theory after a renormalization of\nthe coupling constant. For $SU(3)$ the scaling window is near $ \\beta = 2 $,\nand the relation between the string tension $\\sigma $ and our lattice QCD\nparameter $ \\Lambda_L $ is $\\sqrt{\\sigma} \\approx 5 \\Lambda_L$.",
        "positive": "QCD in a moving frame: an exploratory study: The framework of shifted boundary conditions has proven to be a very powerful\ntool for the non-perturbative investigation of thermal quantum field theories.\nFor instance, it has been successfully considered for the determination of the\nequation of state of SU(3) Yang-Mills theory with high accuracy. The set-up can\nbe generalized to QCD and it is expected to lead to a similar breakthrough. We\npresent first results for QCD with three flavours of non-perturbatively\nO($a$)-improved Wilson fermions and shifted boundary conditions."
    },
    {
        "anchor": "Derivative expansion in the HAL QCD method for a separable potential: We investigate how the derivative expansion in the HAL QCD method works to\nextract physical observables, using a separable potential in quantum mechanics,\nwhich is solvable but highly non-local in the coordinate system. We consider\nthree cases for inputs to determine the HAL QCD potential in the derivative\nexpansion, (1) energy eigenfunctions (2) time-dependent wave functions as\nsolutions to the time dependent Schr\\\"odinger equation with some boundary\nconditions (3) time-dependent wave function made by a linear combination of\nfinite number of eigenfunctions at low energy to mimic the finite volume\neffect. We have found that, for all three cases, the potentials provide\nreasonable scattering phase shifts even at the leading order of the derivative\nexpansion, and they give more accurate results as the order of the expansion\nincreases. By comparing the above results with those from the formal derivative\nexpansion for the separable potential, we conclude that the derivative\nexpansion is not a way to obtain the potential but a method to extract physical\nobservables such as phase shifts and binding energies, and that the scattering\nphase shifts from the derivative expansion in the HAL QCD method converge to\nthe exact ones much faster than those from the formal derivative expansion of\nthe separable potential.",
        "positive": "Finite volume corrections to LECs in Wilson and staggered ChPT: We study the simultaneous effect of finite volume and finite lattice spacing\ncorrections in the framework of chiral perturbation theory (ChPT) in the\nepsilon regime, for both the Wilson and staggered formulations. In particular\nthe finite volume corrections to the low energy constants (LECs) in Wilson and\nstaggered ChPT are computed to next-to-leading order (NLO) in the\n\\epsilon-expansion. For Wilson with N_f = 2 flavours and staggered with generic\nN_f the partition function at NLO can be rewritten as the LO partition function\nwith renormalized effective LECs."
    },
    {
        "anchor": "Operator product expansion and quark condensate from LQCD in coordinate\n  space: We perform an exploratory study of the operator product expansion of the\nquark propagator on the lattice at short distance in coordinate space. This\npermits a simple determination of the quark condensate, <qq>^MS(2 GeV)=(-265\\pm\n5\\pm 22 MeV)^3, and of the renormalization constant of the quark field, Z^MS(2\nGeV)=0.871 \\pm 0.003 \\pm 0.020. This new method also provides a remarkable\nnon-perturbative test of the OPE predictions at short distance in QCD.",
        "positive": "Determining the mass anomalous dimension through the eigenmodes of Dirac\n  operator: We define a scale-dependent effective mass anomalous dimension from the\nscaling of the mode number of the massless Dirac operator, which connects the\nperturbative $\\gamma_m$ of an asymptotically-free system to the universal\n$\\gamma_m^{\\star}$ at a conformal fixed point. We use a stochastic algorithm to\nmeasure the mode number up to the cutoff scale on lattices as large as $48^4$.\nFocusing on SU(3) lattice gauge theory with $N_f = 12$ massless fundamental\nfermions, we examine systematic effects due to finite volumes and non-zero\nfermion masses. Our results suggest the existence of an infrared fixed point\nwith $\\gamma_m^{\\star} \\approx 0.25$. Our method provides a unique probe to\nstudy systems from the UV to the IR. It is universal and can be applied to any\nlattice model of interest, including both chirally-broken and IR-conformal\nsystems."
    },
    {
        "anchor": "Modelling the quark propagator: The quark propagator is at the core of lattice hadron spectrum calculations\nas well as studies in other nonperturbative schemes. We investigate the quark\npropagator with an improved staggered action (Asqtad) and an improved gluon\naction, which provides good quality data down to small quark masses. This is\nused to construct ans\\\"{a}tze suitable for model hadron calculations as well as\nadding to our intuitive understanding of QCD.",
        "positive": "Bianchi Identities and Degeneracy of Chromomagnetic Fields in SU(2)\n  Gluodynamics: We investigate the non-Abelian Bianchi identities in pure SU(2) lattice\nYang-Mills theory in three and four dimensions. The non-Abelian Stokes theorem\nproposed recently allows to formulate the Bianchi identities in terms of local\nphysical fluxes. Then the violation of Bianchi identities becomes a well\ndefined concept ultimately related to chromomagnetic fields degeneracy points.\nWe present numerical evidences that in D=4 the suppression of the Bianchi\nidentities violation destroys confinement while the removal of the degeneracy\npoints drives the theory to the topologically non-trivial sector."
    },
    {
        "anchor": "Wavelet-induced renormalization group for the Landau-Ginzburg model: The scale hierarchy of wavelets provides a natural frame for renormalization.\nExpanding the order parameter of the Landau-Ginzburg/$\\Phi^4$ model in a basis\nof compact orthonormal wavelets explicitly exhibits the coupling between scales\nthat leads to non-trivial behavior. The locality properties of Daubechies'\nwavelets enable us to derive the qualitative renormalization flow of the\nLandau-Ginzburg model from Gaussian fluctuations in wavelet space.",
        "positive": "Axial U(1) symmetry and mesonic correlators at high temperature in\n  $N_f=2$ lattice QCD: We investigate the high-temperature phase of QCD using lattice QCD\nsimulations with $N_f = 2$ dynamical M\\\"obius domain-wall fermions. On\ngenerated configurations, we study the axial $U(1)$ symmetry, overlap-Dirac\nspectra, screening masses from mesonic correlators, and topological\nsusceptibility. We find that some of the observables are quite sensitive to\nlattice artifacts due to a small violation of the chiral symmetry. For those\nobservables, we reweight the M\\\"obius domain-wall fermion determinant by that\nof the overlap fermion. We also check the volume dependence of observables. Our\ndata near the chiral limit indicates a strong suppression of the axial $U(1)$\nanomaly at temperatures $\\geq$ 220 MeV."
    },
    {
        "anchor": "Thermodynamics of free Domain Wall fermions: Studying various thermodynamic quantities for the free domain wall fermions\nfor both finite and infinite fifth dimensional extent N_5, we find that the\nlattice corrections are minimum for $N_T\\geq10$ for both energy density and\nsusceptibility, for its irrelevant parameter M in the range 1.45-1.50. The\ncorrection terms are, however, quite large for small lattice sizes of\n$N_T\\leq8$. We propose modifications of the domain wall operator, as well as\nthe overlap operator, to reduce the finite cut-off effects to within 10% of the\ncontinuum results of the thermodynamic quantities for the currently used\nN_T=6-8 lattices. Incorporating chemical potential, we show that \\mu^2\ndivergences are absent for a large class of such domain wall fermion actions\nalthough the chiral symmetry is broken for $\\mu\\neq0$.",
        "positive": "In Medium Hadron Properties: We discuss modifications of hadron properties in the heat bath extracted from\nEuclidian correlation functions and spectral functions r econstructed with the\nMaximum Entropy Method. To investigate the cut-off dependencies we perform\nsimulation on various lattice sizes and present the result of an analytic\ncalculation of the mesonic spectral functions in the infinite temperature\nlimit."
    },
    {
        "anchor": "The electric dipole moment of the nucleon from simulations at imaginary\n  vacuum angle theta: We compute the electric dipole moment of proton and neutron from lattice QCD\nsimulations with N_f=2 flavors of dynamical quarks at imaginary vacuum angle\ntheta. The calculation proceeds via the CP odd form factor F_3. A novel feature\nof our calculation is that we use partially twisted boundary conditions to\nextract F_3 at zero momentum transfer. As a byproduct, we test the QCD vacuum\nat nonvanishing theta.",
        "positive": "Hadronic Resonances from Lattice QCD: The determination of the pattern of hadronic resonances as predicted by\nQuantum Chromodynamics requires the use of non-perturbative techniques. Lattice\nQCD has emerged as the dominant tool for such calculations, and has produced\nmany QCD predictions which can be directly compared to experiment. The concepts\nunderlying lattice QCD are outlined, methods for calculating excited states are\ndiscussed, and results from an exploratory Nucleon and Delta baryon spectrum\nstudy are presented."
    },
    {
        "anchor": "The $B_{(s)} \\to D_{(s)}l\u03bd$ Decay with Highly Improved Staggered\n  Quarks and NRQCD: We report on progress of a lattice QCD calculation of the $B\\to Dl\\nu$ and\n$B_s\\to D_s l\\nu$ semileptonic form factors. We use a relativistic staggered\naction (HISQ) for light and charm quarks, and an improved non-relativistic\n(NRQCD) action for bottom, on the second generation MILC ensembles.",
        "positive": "Monte Carlo Methods in Quantum Field Theory: In these lecture notes some applications of Monte Carlo integration methods\nin Quantum Field Theory - in particular in Quantum Chromodynamics - are\nintroduced and discussed."
    },
    {
        "anchor": "Performance of a Lattice Quantum Chromodynamics Kernel on the Cell\n  Processor: The implementation of a proof-of-concept Lattice Quantum Chromodynamics\nkernel on the Cell processor is described in detail, illustrating issues\nencountered in the porting process. The resulting code performs up to 45GFlop/s\nper socket, indicating that the Cell processor is likely to be a good platform\nfor future Lattice QCD calculations.",
        "positive": "QPACE -- a QCD parallel computer based on Cell processors: QPACE is a novel parallel computer which has been developed to be primarily\nused for lattice QCD simulations. The compute power is provided by the IBM\nPowerXCell 8i processor, an enhanced version of the Cell processor that is used\nin the Playstation 3. The QPACE nodes are interconnected by a custom,\napplication optimized 3-dimensional torus network implemented on an FPGA. To\nachieve the very high packaging density of 26 TFlops per rack a new water\ncooling concept has been developed and successfully realized. In this paper we\ngive an overview of the architecture and highlight some important technical\ndetails of the system. Furthermore, we provide initial performance results and\nreport on the installation of 8 QPACE racks providing an aggregate peak\nperformance of 200 TFlops."
    },
    {
        "anchor": "Glueballs on the three-sphere: We study the non-perturbative effects of the global features of the\nconfiguration space for SU(2) gauge theory on the three-sphere. The strategy is\nto reduce the full problem to an effective theory for the dynamics of the\nlow-energy modes. By explicitly integrating out the high-energy modes, the\none-loop correction to the effective hamiltonian is obtained. Imposing the\n$\\theta$ dependence through boundary conditions in configuration space\nincorporates the non-perturbative effects of the non-contractable loops in the\nfull configuration space. After this we obtain the glueball spectrum of the\neffective theory with a variational method.",
        "positive": "Lattice QCD Calculation of the $\u03c1$ Meson Decay Width: We present a lattice QCD calculation of the $\\rho$ meson decay width via the\n$P$-wave scattering phase shift for the I=1 two-pion system. Our calculation\nuses full QCD gauge configurations for $N_f=2$ flavors generated using a\nrenormalization group improved gauge action and an improved Wilson fermion\naction on a $12^3\\times24$ lattice at $m_\\pi/m_\\rho=0.41$ and the lattice\nspacing $1/a=0.92 {\\rm GeV}$. The phase shift calculated with the use of the\nfinite size formula for the two-pion system in the moving frame shows a\nbehavior consistent with the existence of a resonance at a mass close to the\nvector meson mass obtained in spectroscopy. The decay width estimated from the\nphase shift is consistent with the experiment, when the quark mass is scaled to\nthe realistic value."
    },
    {
        "anchor": "$K$ to $\u03c0\u03c0$ Decay amplitudes from Lattice QCD: We report a direct lattice calculation of the $K$ to $\\pi\\pi$ decay matrix\nelements for both the $\\Delta I=1/2$ and 3/2 amplitudes $A_0$ and $A_2$ on 2+1\nflavor, domain wall fermion, $16^3\\times32\\times16$ lattices. This is a\ncomplete calculation in which all contractions for the required ten, four-quark\noperators are evaluated, including the disconnected graphs in which no quark\nline connects the initial kaon and final two-pion states. These lattice\noperators are non-perturbatively renormalized using the Rome-Southampton method\nand the quadratic divergences are studied and removed. This is an important but\nnotoriously difficult calculation, requiring high statistics on a large volume.\nIn this paper we take a major step towards the computation of the physical\n$K\\to\\pi\\pi$ amplitudes by performing a complete calculation at unphysical\nkinematics with pions of mass 422\\,MeV at rest in the kaon rest frame. With\nthis simplification we are able to resolve Re$(A_0)$ from zero for the first\ntime, with a 25% statistical error and can develop and evaluate methods for\ncomputing the complete, complex amplitude $A_0$, a calculation central to\nunderstanding the $\\Delta =1/2$ rule and testing the standard model of CP\nviolation in the kaon system.",
        "positive": "Lattice Gauge Fixing for Parameter Dependent Covariant Gauges: We propose a non-perturbative procedure to fix generic covariant gauges on\nthe lattice. Varying the gauge parameter, this gauge fixing provides a concrete\nmethod to check numerically the gauge dependence of correlators measured on the\nlattice. The new algorithm turns out to converge with a good efficiency. As a\npreliminary physical result, we find a sensitive dependence of the gluon\npropagator on the gauge parameter."
    },
    {
        "anchor": "Topological Susceptibility to the One-Loop Order in Chiral Perturbation\n  Theory: We derive the topological susceptibility to the one-loop order in the chiral\neffective theory of QCD, for an arbitrary number of flavors.",
        "positive": "Loop formulation of supersymmetric Yang-Mills quantum mechanics: We derive the fermion loop formulation of N=4 supersymmetric SU(N) Yang-Mills\nquantum mechanics on the lattice. The loop formulation naturally separates the\ncontributions to the partition function into its bosonic and fermionic parts\nwith fixed fermion number and provides a way to control potential fermion sign\nproblems arising in numerical simulations of the theory. Furthermore, we\npresent a reduced fermion matrix determinant which allows the projection into\nthe canonical sectors of the theory and hence constitutes an alternative\napproach to simulate the theory on the lattice."
    },
    {
        "anchor": "Improving the Lattice QCD Hamiltonian: Improvement of the Hamiltonian in lattice gauge theory is considered. We give\nexplicit expressions for classical improvement and discuss also quantum\ncorrections.",
        "positive": "Nucleon in a periodic magnetic field: Finite-volume aspects: The paper presents an extension and a refinement of our previous work on the\nextraction of the doubly virtual forward Compton scattering amplitude on the\nlattice by using the background field technique, Phys. Rev. D 95, 031502 (2017)\n(arXiv:1610.05545). The zero frequency limit for the periodic background field\nis discussed, in which the well-known result is reproduced. Further, an upper\nlimit for the magnitude of the external field is established for which the\nperturbative treatment is still possible. Finally, the framework is set for the\nevaluation of the finite-volume corrections allowing for the analysis of\nupcoming lattice results."
    },
    {
        "anchor": "Real-Time-Evolution of Heavy Quarks in the Glasma: We introduce a novel real-time formulation of lattice NRQCD designed for\nsimulations in the background of an highly occupied gluon field. By evolving\nquarks in the background of a dynamically evolving gluon field we computed the\ntime-evolution of heavy-quarkonium spectral functions as well as the static and\nfor finitely heavy quarks generalised potential. We conclude that the back\nreaction of the quarks is necessary for any binding process. Here we discuss\nthe methodology, our results and the origin of the absence of a binding\nprocess.",
        "positive": "The High-Temperature Expansion of the Hierarchical Ising Model: From\n  Poincar\u00e9 Symmetry to an Algebraic Algorithm: We show that the hierarchical model at finite volume has a symmetry group\nwhich can be decomposed into rotations and translations as the familiar\nPoincar\\'e groups. Using these symmetries, we show that the intricate sums\nappearing in the calculation of the high-temperature expansion of the magnetic\nsusceptibility can be performed, at least up to the fourth order, using\nelementary algebraic manipulations which can be implemented with a computer.\nThese symmetries appear more clearly if we use the 2-adic fractions to label\nthe sites. We then apply the new algebraic methods to the calculation of\nquantities having a random walk interpretation. In particular, we show that the\nprobability of returning at the starting point after $m$ steps has poles at\n$D=-2,-4,....-2m$ , where $D$ is a free parameter playing a role similar to the\ndimensionality in nearest neighbor models."
    },
    {
        "anchor": "Gluons, quarks and deconfinement at high density: We compute gluon and quark propagators in 2-colour QCD at large baryon\nchemical potential mu. The gluon propagator is found to be antiscreened in the\nsuperfluid, confined phase and screened in the large-mu, deconfined phase. We\npresent the first attempt to determine corresponding electric and magnetic\ngluon masses. The quark propagator undergoes dramatic modifications in the\nsuperfluid region as a result of the formation of a superfluid gap. These\nmodifications include the appearance of zero crossings in the vector part of\nthe (normal) quark propagator, a large suppression of the scalar part, and the\nemergence of anomalous propagation.",
        "positive": "A streamlined method for chiral fermions on the lattice: We discuss the use of renormalization counterterms to restore the chiral\ngauge symmetry in a lattice theory of Wilson fermions. We show that a large\nclass of counterterms can be implemented automatically by making a simple\nmodification to the fermion determinant."
    },
    {
        "anchor": "O(a) Perturbative improvement for Wilson fermions: The coefficient of the O(a)-improved\n  Sheikholeslami-Wohlert action for Wilson fermions are perturbatively\ndetermined at one-loop level and estimated at two-loop level.",
        "positive": "Update of $|V_{cb}|$ from the $\\bar{B}\\to D^*\\ell\\bar\u03bd$ form factor\n  at zero recoil with three-flavor lattice QCD: We compute the zero-recoil form factor for the semileptonic decay\n$\\bar{B}^0\\to D^{*+}\\ell^-\\bar{\\nu}$ (and modes related by isospin and charge\nconjugation) using lattice QCD with three flavors of sea quarks. We use an\nimproved staggered action for the light valence and sea quarks (the MILC\n\\asqtad\\ configurations), and the Fermilab action for the heavy quarks. Our\ncalculations incorporate higher statistics, finer lattice spacings, and lighter\nquark masses than our 2008 work. As a byproduct of tuning the new data set, we\nobtain the $D_s$ and $B_s$ hyperfine splittings with few-MeV accuracy. For the\nzero-recoil form factor, we obtain $\\mathcal{F}(1)=0.906(4)(12)$, where the\nfirst error is statistical and the second is the sum in quadrature of all\nsystematic errors. With the latest HFAG average of experimental results and a\ncautious treatment of QED effects, we find $|V_{cb}| = (39.04 \\pm\n0.49_\\text{expt} \\pm 0.53_\\text{QCD} \\pm 0.19_\\text{QED})\\times10^{-3}$. The\nQCD error is now commensurate with the experimental error."
    },
    {
        "anchor": "Effects of higher dimension operators on the Standard Model Higgs sector: We study the effect of higher dimension operators on the electroweak finite\ntemperature phase transition in two sectors of the Standard Model. Firstly, the\nHiggs-Yukawa sector, consisting of the Higgs doublet and the massive Standard\nModel fermions, is studied with an approximate method, Extended Mean Field\nTheory. Secondly, the gauge-Higgs sector, consisting of the Higgs doublet and\nthe gauge fields of the weak interaction, is studied using Monte Carlo\nsimulations. In both cases we find that a cutoff scale of around 1.5 TeV is\nneeded to make the electroweak phase transition first order at the experimental\nvalue of the Higgs boson mass, which is a requirement for making electroweak\nbaryogenesis viable.",
        "positive": "Lattice field theory results for hybrid static potentials at short\n  quark-antiquark separations and their parametrization: We present SU(3) lattice Yang-Mills data for hybrid static potentials from\nfive ensembles with different small lattice spacings and the corresponding\nparametrizations for quark-antiquark separations $0.08\\,\\text{fm} \\le r \\le\n1.12\\,\\text{fm}$. We remove lattice discretization errors at tree level of\nperturbation theory and partly at order $a^2$ as well as the $a$-dependent self\nenergy. In particular the tree-level improvement of static potentials is\ndiscussed in detail and two methods are compared. The resulting\nparametrizations are expected to represent continuum limit results for hybrid\nstatic potentials within statistical errors."
    },
    {
        "anchor": "Flux-tubes in three-dimensional lattice gauge theories: Flux-tubes in different representations of SU(2) and U(1) lattice gauge\ntheories in three dimensions are measured. Wilson loops generate heavy\n``quark-antiquark'' pairs in fundamental ($j=1/2$), adjoint ($j=1$), and\nquartet ($j=3/2$) representations of SU(2). The first direct lattice\nmeasurements of the flux-tube cross-section ${\\cal A}_j$ as a function of\nrepresentation are made. It is found that ${\\cal A}_j \\approx {\\rm constant}$,\nto about 10\\%. Results are consistent with a connection between the string\ntension $\\sigma_j$ and ${\\cal A}_j$ suggested by a simplified flux-tube model,\n$\\sigma_j = g^2 j(j+1) / (2 {\\cal A}_j)$ [$g$ is the gauge coupling], given\nthat $\\sigma_j$ scales like the Casimir $j(j+1)$, as observed in previous\nlattice studies in both three and four dimensions. The results can discriminate\namong phenomenological models of the physics underlying confinement. Flux-tubes\nfor singly- and doubly-charged Wilson loops in compact QED$_3$ are also\nmeasured. It is found that the string tension scales as the squared-charge and\nthe flux-tube cross-section is independent of charge to good approximation.\nThese SU(2) and U(1) simulations lend some support, albeit indirectly, to a\nconjecture that the dual superconductor mechanism underlies confinement in\ncompact gauge theories in both three and four dimensions.",
        "positive": "Static quark anti-quark interactions in zero and finite temperature QCD.\n  I. Heavy quark free energies, running coupling and quarkonium binding: We analyze heavy quark free energies in 2-flavor QCD at finite temperature\nand the corresponding heavy quark potential at zero temperature. Static quark\nanti-quark sources in color singlet, octet and color averaged channels are used\nto probe thermal modifications of the medium. The temperature dependence of the\nrunning coupling, $\\alpha_{qq}(r,T)$, is analyzed at short and large distances\nand is compared to zero temperature as well as quenched calculations. In parts\nwe also compare our results to recent findings in 3-flavor QCD. We find that\nthe characteristic length scale below which the running coupling shows almost\nno temperature dependence is almost twice as large as the Debye screening\nradius. Our analysis supports recent findings which suggest that $\\chi_c$ and\n$\\psi\\prime$ are suppressed already at the (pseudo-) critical temperature and\nthus give a probe for quark gluon plasma production in heavy ion collision\nexperiments, while $J/\\psi$ may survive the transition and will dissolve at\nhigher temperatures."
    },
    {
        "anchor": "Improved Lattice QCD Actions for Hadron Phenomenology: The masses and dispersions of light hadrons are calculated in lattice QCD\nusing an order a^2 tadpole-improved gluon action and the Dchi34 action, an\norder a^2 tadpole-improved next-nearest-neighbor fermion action originally\nproposed by Hamber and Wu. Two lattices of constant volume with lattice\nspacings of approximately 0.40 fm and 0.24 fm are considered. The results\nreveal some scaling violations at the coarser lattice spacing on the order of\n5%. At the finer lattice spacing, the calculated N/rho mass ratio reproduces\nstate-of-the-art results using unimproved actions. Good dispersion and\nrotational invariance up to momenta p*a the order of 1 are also found. The\nrelative merit of alternative choices for improvement operators is assessed\nthrough close comparisons with other plaquette-based tadpole-improved actions.",
        "positive": "B and Bs semileptonic decay form factors with NRQCD/HISQ quarks: We discuss our ongoing effort to calculate form factors for several B and Bs\nsemileptonic decays. We have recently completed the first unquenched\ncalculation of the form factors for the rare decay B -> K ll. Extrapolated over\nthe full kinematic range of q^2 via model-independent z expansion, these form\nfactor results allow us to calculate several Standard Model observables. We\ncompare with experiment (Belle, BABAR, CDF, and LHCb) where possible and make\npredictions elsewhere. We discuss preliminary results for Bs -> K l nu which,\nwhen combined with anticipated experimental results, will provide an\nalternative exclusive determination of |Vub|. We are exploring the possibility\nof using ratios of form factors for this decay with those for the unphysical\ndecay Bs -> eta_s as a means of significantly reducing form factor errors. We\nare also studying B -> pi l nu, form factors for which are combined with\nexperiment in the standard exclusive determination of |Vub|. Our simulations\nuse NRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad\nconfigurations."
    },
    {
        "anchor": "Mass Splitting in a Linear Sigma Model: We derived the tree level spectrum to an extension to the linear sigma model\ndescribing an EFT for an $SU(3)_c$ gauge theory with $N_f$ flavors of fermions\nand $N_1$ fermions have a mass $m_l$ and $N_2$ fermions have a mass $m_h$. We\nexamined the effects of a small mass splitting on single mass data for 8 and 12\nflavors of fermions corresponding to the unperturbed case. Our intention is to\nencourage more simulations of split mass theories with 8, 10 and 12 flavors of\nfermions.",
        "positive": "Topology near the transition temperature in lattice gluodynamics\n  analyzed by low lying modes of the overlap Dirac operator: Topological objects of $SU(3)$ gluodynamics are studied at the infrared scale\nnear the transition temperature with the help of zero and near-zero modes of\nthe overlap Dirac operator. We construct UV filtered topological charge\ndensities corresponding to three versions of the temporal boundary condition\napplied to this operator, for which the zero mode is known to be located on\ncorresponding three constituent dyons (antidyons) in the reference case of an\nanalytical (anti)caloron solution. The clustering of the three topological\ncharge densities marks the positions of three types of dyons and antidyons\nwhich can therefore be considered as present in equilibrium (Monte Carlo)\ngluonic fields at the given resolution scale. We classify them either as\nconstituents of nondissociated (anti)calorons or as constituents of (anti)dyon\npairs or as isolated (anti)dyons. The pattern of the Polyakov loop describing\nthe centers and the interior of these clusters is observed after a limited\nnumber of overimproved cooling steps and resembles the description known from\nanalytical caloron solutions."
    },
    {
        "anchor": "Kaon mixing matrix elements from beyond-the-Standard-Model operators in\n  staggered chiral perturbation theory: Models of new physics induce K-Kbar mixing operators having Dirac structures\nother than the \"left-left\" form of the Standard Model. We calculate the\nfunctional form of the corresponding B-parameters at next-to-leading order in\nboth SU(3) and SU(2) staggered chiral perturbation theory (SChPT). Numerical\nresults for these matrix elements are being generated using improved staggered\nfermions; our results can be used to extrapolate these matrix elements to the\nphysical light and strange quark masses. The SU(3) SChPT results turn out to be\nmuch simpler than that for the Standard Model B_K operator, due to the absence\nof chiral suppression in the new operators. The SU(2) SChPT result is of\nsimilar simplicity to that for B_K. In fact, in the latter case, the chiral\nlogarithms for two of the new B-parameters are identical to those for B_K,\nwhile those for the other two new B-parameters are of opposite sign. In\naddition to providing results for the 2+1 flavor theory in SU(3) SChPT and the\n1+1+1 flavor theory in SU(2) SChPT, we present the corresponding continuum\npartially quenched results, as these are not available in the literature.",
        "positive": "Precise Determination of the I=2 pipi Scattering Length from\n  Mixed-Action Lattice QCD: The I=2 pipi scattering length is calculated in fully-dynamical lattice QCD\nwith domain-wall valence quarks on the asqtad-improved coarse MILC\nconfigurations (with fourth-rooted staggered sea quarks) at four light-quark\nmasses. Two- and three-flavor mixed-action chiral perturbation theory at\nnext-to-leading order is used to perform the chiral and continuum\nextrapolations. At the physical charged pion mass, we find m_pi a_pipi(I=2) =\n-0.04330 +- 0.00042, where the error bar combines the statistical and\nsystematic uncertainties in quadrature."
    },
    {
        "anchor": "Recent progress on cluster and meron algorithms for strongly correlated\n  systems: Ab-initio studies of strongly interacting bosonic and fermionic systems is\ngreatly facilitated by efficient Monte Carlo algorithms. This article\nemphasizes this requirement, and outlines the ideas behind the construction of\nthe cluster algorithms and illustrates them via specific examples. Numerical\nstudies of fermionic systems at finite densities and at real-times are\nsometimes hindered by the infamous sign problem, which is also discussed. The\nconstruction of meron cluster algorithms, which can solve certain sign problems\nare discussed. Cluster algorithms which can simulate certain pure Abelian gauge\ntheories (realized as quantum link models) are also discussed.",
        "positive": "Interpolation of Non-abelian Lattice Gauge Fields: We propose a method for interpolating non-abelian lattice gauge fields to the\ncontinuum, or to a finer lattice, which satisfies the properties of (i)\ntransverse continuity, (ii) (lattice) rotation and translation covariance,\n(iii) gauge covariance, (iv) locality. These are the properties required for\nuse in our earlier proposal for non-perturbative formulation and simulation of\nchiral gauge theories."
    },
    {
        "anchor": "Polyakov Loop Percolation and Deconfinement in SU(2) Gauge Theory: The deconfinement transition in SU(2) gauge theory and the magnetization\ntransition in the Ising model belong to the same universality class. The\ncritical behaviour of the Ising model can be characterized either as\nspontaneous breaking of the Z_2 symmetry of spin states or as percolation of\nappropriately defined spin clusters. We show that deconfinement in SU(2) gauge\ntheory can be specified as percolation of Polyakov loop clusters with\nFortuin-Kasteleyn bond weights, leading to the same (Onsager) critical\nexponents as the conventional order-disorder description based on the Polyakov\nloop expectation value.",
        "positive": "Green's Function Monte Carlo study of correlation functions in the\n  (2+1)D U(1) lattice gauge theory: A ``forward walking'' Quantum Monte Carlo (QMC) algorithm has been developed\nto calculate correlation functions for the Hamiltonian lattice formulation of\nU(1) Yang-Mills theory in (2+1) dimensions. It is shown that Wilson loops can\nbe calculated with high accuracy. Creutz ratios are used to determine the\nstring tension, which agrees with results from other approaches. Timelike\ncorrelations are used to estimate the mass gaps, which agree with series\nexpansion results in the strong coupling regime."
    },
    {
        "anchor": "Nucleon-pion-state contamination in lattice calculations of the axial\n  form factors of the nucleon: The nucleon-pion-state contribution to QCD two- and three-point functions\nused in the calculation of the axial form factors of the nucleon are studied in\nchiral perturbation theory. For physically small quark masses the nucleon-pion\nstates are expected to dominante the excited-state contamination at large\neuclidean time separations. To leading order in chiral perturbation theory the\nresults depend on two experimentally well-known low-energy constants only and\nthe nucleon-pion-state contribution can be reliably estimated. The\nnucleon-pion-state contribution to the axial form factor $G_{\\rm A}(Q^2)$ is at\nthe 5 percent level for source-sink separations of 2 fm and shows almost no\ndependence on the momentum transfer $Q^2$. In contrast, for the induced pseudo\nscalar form factor $G_{\\rm P}(Q^2)$ the nucleon-pion-state contribution shows a\nrather strong dependence on $Q^2$ and leads to a 10 to 40 percent\nunderestimation of $G_{\\rm P}(Q^2)$ at small momentum transfers. Applying the\nChPT results to recent lattice data generated by the PACS collaboration we find\nagreement with experimental data and the predictions of the pion-pole dominance\nmodel.",
        "positive": "First exploratory calculation of the long-distance contributions to the\n  rare kaon decays $K\\to\u03c0\\ell^+\\ell^-$: The rare decays of a kaon into a pion and a charged lepton/antilepton pair\nproceed via a flavour changing neutral current and therefore may only be\ninduced beyond tree level in the Standard Model. This natural suppression makes\nthese decays sensitive to the effects of potential New Physics. The CP\nconserving $K\\to\\pi \\ell^+\\ell^-$ decay channels however are dominated by a\nsingle photon exchange; this involves a sizeable long-distance hadronic\ncontribution which represents the current major source of theoretical\nuncertainty. Here we outline our methodology for the computation of the\nlong-distance contributions to these rare decay amplitudes using lattice QCD\nand present the numerical results of the first exploratory studies of these\ndecays in which all but the disconnected diagrams are evaluated. The domain\nwall fermion ensembles of the RBC and UKQCD collaborations are used, with a\npion mass of $M_{\\pi}\\sim 430\\,\\mathrm{MeV}$ and a kaon mass of $M_{K}\\sim\n625\\,\\mathrm{MeV}$. In particular we determine the form factor, $V(z)$, of the\n$K^+\\to\\pi^+\\ell^+\\ell^-$ decay from the lattice at small values of\n$z=q^2/M_{K}^{2}$, obtaining $V(z)=1.37(36),\\, 0.68(39),\\, 0.96(64)$ for the\nthree values of $z=-0.5594(12),\\, -1.0530(34),\\, -1.4653(82)$ respectively."
    },
    {
        "anchor": "Study of QCD critical point using the canonical ensemble method: The existence of the QCD critical point at non-zero baryon density is not\nonly of great interest for experimental physics but also a challenge for the\ntheory. Any hint of the existence of the first order phase transition and,\nparticularly, its critical point will be valuable towards a full understanding\nof the QCD phase diagram. We use lattice simulation based on the canonical\nensemble method to explore the finite baryon density and finite temperature\nregion and look for the QCD critical point. As a benchmark, we run simulations\nfor the four degenerate flavor QCD where we observe a clear signal of the\nexpected first order phase transition. In the two flavor case, we do not see\nany signal for temperatures as low as $0.83 \\rm{T_c}$. Although our real world\ncontains two light quarks and one heavier quark, three degenerate flavor case\nshares a lot of similar phase structures as the QCD. We scan the phase diagram\nusing clover fermions with $m_\\pi \\approx 700{MeV}$ on $6^3\\times4$ lattices.\nThe baryon chemical potential is measured as we increase the baryon number and\nwe see the characteristic \"S-shape\" that signals the first order phase\ntransition. We determine the phase boundaries by Maxwell construction and\nreport our preliminary results for the location of critical point for the\npresent lattice.",
        "positive": "Inverse problems, real-time dynamics and lattice simulations: The determination of real-time dynamics of strongly coupled quantum fields is\na central goal of modern nuclear and particle physics, which requires insight\ninto quantum field theory beyond the weak-coupling approximation. While lattice\nQCD has provided vital insights into the non-perturbative static properties of\nquarks and gluons it hides their real-time dynamics behind an ill-posed inverse\nproblem. In this proceeding I will discuss developments in tackling the inverse\nproblem on the lattice and touch upon progress in the direct simualtion of\nreal-time dynamics."
    },
    {
        "anchor": "Some nucleon isovector observables from 2+1-flavor domain-wall QCD at\n  the physical pion mass: The current status of the LHP and RBC joint calculations of the nucleon\nisovector form factors and low moments of structure functions with a 2+1-flavor\ndynamical domain-wall fermion (DWF) lattice-QCD ensemble at the physical pion\nmass generated by RBC and UKQCD Collaborations with a momentum cutoff of\n1.730(4) GeV and lattice spatial extent of 5.476(12) fm is reported. About ten\npercent of the statistics reported in Lattice 2014 were found with an incorrect\nboundary condition in time but correcting for it resulted in less than\none-percent difference.",
        "positive": "Unphysical properties of the static quark-antiquark four-point\n  correlator in Landau gauge: We consider the four point connected correlator representing a static\nquark-antiquark pair separated by a spatial distance R, propagating for a\nEuclidean time T. This function is computed by lattice Monte Carlo in SU(2)\npure gauge theory at lattice couplings $\\beta=2.2$ and $\\beta=2.5$ in both\nCoulomb and Landau gauges. The Coulomb gauge correlator is well behaved, and is\ndominated at large T by a state whose energy grows linearly as $\\sigma R$, with\n$\\sigma$ the known asymptotic string tension. The connected correlator in\nLandau gauge behaves differently. At intermediate R there is clear evidence of\na linear potential, but the corresponding string tension extrapolates to zero\nat large T. At large R the connected correlator becomes negative; moreover\nthere are strong finite size effects. These numerical results suggest that\nunphysical states dominate the large Euclidean time behavior of this Landau\ngauge correlator."
    },
    {
        "anchor": "${\\cal N} = 2^*$ Yang-Mills on the Lattice: The ${\\cal N} = 2^*$ Yang-Mills theory in four dimensions is a non-conformal\ntheory that appears as a mass deformation of maximally supersymmetric ${\\cal N}\n= 4$ Yang-Mills theory. This theory also takes part in the AdS/CFT\ncorrespondence and its gravity dual is type IIB supergravity on the\nPilch-Warner background. The finite temperature properties of this theory have\nbeen studied recently in the literature. It has been argued that at large $N$\nand strong coupling this theory exhibits no thermal phase transition at any\nnon-zero temperature. The low temperature ${\\cal N} = 2^*$ plasma can be\ncompared to the QCD plasma. We provide a lattice construction of ${\\cal N} =\n2^*$ Yang-Mills on a hypercubic lattice starting from the ${\\cal N} = 4$ gauge\ntheory. The lattice construction is local, gauge-invariant, free from fermion\ndoubling problem and preserves a part of the supersymmetry. This\nnonperturbative formulation of the theory can be used to provide a highly\nnontrivial check of the AdS/CFT correspondence in a non-conformal theory.",
        "positive": "New DoS approaches to finite density lattice QCD: We present two new suggestions for density of states (DoS) approaches to\nfinite density lattice QCD. Both proposals are based on the recently developed\nand successfully tested DoS FFA technique, which is a DoS approach for bosonic\nsystems with a complex action problem. The two different implementations of DoS\nFFA we suggest for QCD make use of different representations of finite density\nlattice QCD in terms of suitable pseudo-fermion path integrals. The first\nproposal is based on a pseudo-fermion representation of the grand canonical QCD\npartition sum, while the second is a formulation for the canonical ensemble. We\nwork out the details of the two proposals and discuss the results of\nexploratory 2-d test studies for free fermions at finite density, where exact\nreference data allow one to verify the final results and intermediate steps."
    },
    {
        "anchor": "Thermal Fluctuations of Chern-Simons Numbers in the Lattice SU(2) Higgs\n  Model: We study the temperature dependence of the Chern-Simons number fluctuations\nin the SU(2) Higgs Model on Euclidean lattices with spatial sizes up to 20^3.\nTemperatures well above the Higgs phase transition $T_H$ are achieved on\nanisotropic lattices. Numerical results are compared to perturbative results on\nfinite lattices as well as in continuum perturbation theory. We find\nqualitative agreement with perturbative estimates and see at high temperatures\na tendency towards static configurations. Up to temperatures $T \\simeq 2T_H$ we\nfind indication that tunneling between vacuums with different Chern-Simons\nnumbers are still exponentially suppressed. (Full PostScript file available via\nEmail from plache@physw.uni-bielefeld.de )",
        "positive": "Supersymmetric quiver gauge theories on the lattice: In this paper we detail the lattice constructions of several classes of\nsupersymmetric quiver gauge theories in two and three Euclidean spacetime\ndimensions possessing exact supersymmetry at finite lattice spacing. Such\nconstructions are obtained through the methods of topological twisting and\ngeometric discretization of Euclidean Yang--Mills theories with eight and\nsixteen supercharges in two and three dimensions. We detail the lattice\nconstructions of two-dimensional quiver gauge theories possessing four and\neight supercharges and three-dimensional quiver gauge theories possessing eight\nsupercharges."
    },
    {
        "anchor": "Numerical study of tree-level improved lattice gradient flows in pure\n  Yang-Mills theory: We study several types of tree-level improvement in the Yang-Mills gradient\nflow method in order to reduce the lattice discretization errors in line with\nFodor et al. [arXiv:1406.0827]. The tree-level $\\mathcal{O}(a^2)$ improvement\ncan be achieved in a simple manner, where an appropriate weighted average is\ncomputed between two definitions of the action density $\\langle E(t)\\rangle$\nmeasured at every flow time $t$. We further develop the idea of achieving the\ntree-level $\\mathcal{O}(a^4)$ improvement. For testing our proposal, we present\nnumerical results for $\\langle E(t) \\rangle$ obtained on gauge configurations\ngenerated with the Wilson and Iwasaki gauge actions at three lattice spacings\n($a\\approx 0.1, 0.07,$ and 0.05 fm). Our results show that tree-level improved\nflows significantly eliminate the discretization corrections on $t^2\\langle\nE(t)\\rangle$ in the relatively small-$t$ regime. To demonstrate the feasibility\nof our tree-level improvement proposal, we also study the scaling behavior of\nthe dimensionless combinations of the $\\Lambda_{\\overline{\\textrm{MS}}}$\nparameter and the new reference scale $t_X$, which is defined through\n$t_X^2\\langle E(t_X)\\rangle=X$ for the smaller $X$, e.g., $X= 0.15$. It is\nfound that $\\sqrt{t_{0.15}}\\Lambda_{\\overline{\\textrm{MS}}}$ shows a nearly\nperfect scaling behavior as a function of $a^2$ regardless of the types of\ngauge action and flow, after tree-level improvement is achieved up to\n$\\mathcal{O}(a^4)$. Further detailed study of the scaling behavior exposes the\npresence of the remnant $\\mathcal{O}(g^{2n} a^2)$ corrections, which are beyond\nthe tree level. Although our proposal is not enough to eliminate all\n$\\mathcal{O}(a^2)$ effects, we show that the $\\mathcal{O}(g^{2n} a^2)$\ncorrections can be well under control even by the simplest tree-level\n$\\mathcal{O}(a^2)$ improved flow.",
        "positive": "Nf=2+1 dynamical Wilson quark simulation toward the physical point: We present preliminary results of the PACS-CS project which simulates 2+1\nflavor lattice QCD toward the physical point with the nonperturbatively\nO(a)-improved Wilson quark action and the Iwasaki gauge action. Calculations\nare carried out at beta=1.9 on a 32^3x64 lattice with the use of the\ndomain-decomposed HMC algorithm to reduce the up-down quark mass. The resulting\npseudoscalar meson masses range from 730 MeV down to 210 MeV. We discuss the\nphysical results including the chiral analysis in the pseudoscalar meson sector\nand the hadron spectrum. Some algorithmic issues are also discussed."
    },
    {
        "anchor": "Nucleon isovector couplings in Nf = 2 + 1 lattice QCD at the physical\n  point: We present results for the scalar and tensor isovector-couplings ($g_S$ and\n$g_T$) of the nucleon measured at the physical point ($M_{\\pi}=135$ MeV) with a\nsingle lattice spacing of $0.085\\ \\mathrm{fm}$ in 2+1 flavor QCD. Our\ncalculations are carried out with two ensembles of gauge configurations\ngenerated by the PACS Collaboration with nonperturbatively ${\\cal O}(a)$\nimproved Wilson quark action and Iwasaki gauge action on $(10.9\\ {\\rm fm})^4$\nand $(5.5\\ {\\rm fm})^4$ lattices, where the finite-size effect on the nucleon\nmass was not shown at the level of the statistical precision less than 0.5%. We\ncompute the nucleon three-point correlation functions in the vector, axial,\nscalar, and tensor channels. We confirm that our previous result of the nucleon\naxial coupling on the large spatial volume of $(10.9\\ {\\rm fm})^4$ has no\nfinite-size effect at the level of the statistical precision of 1.9%. For the\nrenormalization, we first renormalize $g_S$ and $g_T$ nonperturbatively using\nthe RI/SMOM$_{(\\gamma_\\mu)}$ scheme, a variant of Rome-Southampton RI/MOM\nscheme with reduced systematic errors, as the intermediate scheme. We evaluate\nour final results at the renormalization scale of 2 GeV in the $\\overline{\\rm\nMS}$ scheme through matching procedure between the RI/SMOM$_{(\\gamma_\\mu)}$ and\n$\\overline{\\rm MS}$ schemes with the help of perturbation theory, and then\nobtain $g_S=0.927(71)_{\\rm stat}(22)_{\\rm syst}$ and $g_T=1.036(6)_{\\rm\nstat}(20)_{\\rm syst}$.",
        "positive": "Systematic Uncertainties in $B_K$ with Improved Staggered Fermions: We study three sources of error in our calculation of $B_K$ using HYP-smeared\nstaggered fermions on the MILC asqtad lattices. These are (1) dependence on the\nlight sea quark mass; (2) finite volume effects; and (3) the impact of an order\nof magnitude increase in the number of measurements. Our main results are (1)\nthe dependence on the light sea-quark mass is weaker than expected by naive\ndimensional analysis, (2) including finite volume effects in SU(2) staggered\nchiral perturbation theory fits leads to a very small change in $B_K$, of size\n$\\approx 0.1%$, and (3) increasing the statistics on one of the coarse MILC\nlattices resolves a potential discrepancy with other coarse results."
    },
    {
        "anchor": "Valence calculation of the electric polarizability on nHYP-Clover\n  ensembles: We present preliminary calculations for the electric polarizability of the\nneutral pion and neutron on three dynamically generated nHYP-Clover ensembles.\nWe use two different pion masses ($m_{\\pi} \\simeq 300$ and 220 MeV) to gauge\nthe chiral behavior. The effects of partial quenching are analyzed by computing\na string of partial quenched valence masses for each ensemble. We also analyzed\nthe volume dependence using elongated lattices, where the elongation is in the\ndirection of the electric field.",
        "positive": "Exploring possibly existing $q q \\bar b \\bar b$ tetraquark states with\n  $q q = ud, ss, cc$: We compute potentials of two static antiquarks in the presence of two quarks\n$qq$ of finite mass using lattice QCD. In a second step we solve the\nSchr\\\"odinger equation, to determine, whether the resulting potentials are\nsufficiently attractive to host a bound state, which would indicate the\nexistence of a stable $q q \\bar b \\bar b$ tetraquark. We find a bound state for\n$qq=(ud-du)/\\sqrt{2}$ with corresponding quantum numbers $I(J^ P)=0(1^+)$ and\nevidence against the existence of bound states with isospin $I=1$ or $qq \\in\n\\{cc,ss \\}$"
    },
    {
        "anchor": "Deflated Hermitian Lanczos Methods for Multiple Right-Hand Sides: A deflated and restarted Lanczos algorithm to solve hermitian linear systems,\nand at the same time compute eigenvalues and eigenvectors for application to\nmultiple right-hand sides, is described. For the first right-hand side,\neigenvectors with small eigenvalues are computed while simultaneously solving\nthe linear system. Two versions of this algorithm are given. The first is\ncalled Lan-DR and is based on conjugate gradient (CG) implementation of the\nLanczos algorithm. This version will be optimal for the hermitian positive\ndefinite case. The second version is called MinRes-DR and is based on the\nminimum residual (MinRes) implementation of Lanczos algorithm. This version is\noptimal for indefinite hermitian systems where the CG algorithm is subject to\ninstabilities. For additional right-hand sides, we project over the calculated\neigenvectors to speed up convergence. The algorithms used for subsequent\nright-hand sides are called D-CG and D-MinRes respectively. After some\nintroductory examples are given, we show tests for the case of Wilson fermions\nat kappa critical. A considerable speed up in the convergence is observed\ncompared to unmodified CG and MinRes.",
        "positive": "Implications of Poincare symmetry for thermal field theories in\n  finite-volume: The analytic continuation to an imaginary velocity $i\\xi$ of the canonical\npartition function of a thermal system expressed in a moving frame has a\nnatural implementation in the Euclidean path-integral formulation in terms of\nshifted boundary conditions. Writing the Boltzmann factor as\n$\\exp[-L_0(H-i\\xi.P)]$, the Poincare invariance underlying a relativistic\ntheory implies a dependence of the free-energy on $L_0$ and the shift $\\xi$\nonly through the combination $\\beta= L_0 \\sqrt{1+\\xi^2}$. This in turn implies\na set of Ward identities, some of which were previously derived by us, among\nthe correlators of the energy-momentum tensor. In the infinite-volume limit\nthey lead to relations among the cumulants of the total energy distribution and\nthose of the momentum, i.e. they connect the energy and the momentum\ndistributions in the canonical ensemble. In finite volume the Poincare symmetry\ntranslates into exact relations among partition functions and correlation\nfunctions defined with different sets of (generalized) periodic boundary\nconditions. They have interesting applications in lattice field theory. In\nparticular, they offer Ward identities to renormalize non-perturbatively the\nenergy-momentum tensor and novel ways to compute thermodynamic potentials. At\nfixed bare parameters they also provide a simple method to vary the temperature\nin much smaller steps than with the standard procedure."
    },
    {
        "anchor": "New Method for Dynamical Fermions and Chiral-Symmetry Breaking: The reasons for the feasibility of the Microcanonical Fermionic Average\n($MFA$) approach to lattice gauge theory with dynamical fermions are discussed.\nWe then present a new exact algorithm, which is free from systematic errors and\nconvergent even in the chiral limit.",
        "positive": "Comparison of topological charge definitions in Lattice QCD: In this paper, we show a comparison of different definitions of the\ntopological charge on the lattice. We concentrate on one small-volume ensemble\nwith 2 flavours of dynamical, maximally twisted mass fermions and use three\nmore ensembles to analyze the approach to the continuum limit. We investigate\nseveral fermionic and gluonic definitions. The former include the index of the\noverlap Dirac operator, the spectral flow of the Wilson--Dirac operator and the\nspectral projectors. For the latter, we take into account different\ndiscretizations of the topological charge operator and various smoothing\nschemes to filter out ultraviolet fluctuations: the gradient flow, stout\nsmearing, APE smearing, HYP smearing and cooling. We show that it is possible\nto perturbatively match different smoothing schemes and provide a well-defined\nsmoothing scale. We relate the smoothing parameters for cooling, stout and APE\nsmearing to the gradient flow time $\\tau$. In the case of hypercubic smearing\nthe matching is performed numerically. We investigate which conditions have to\nbe met to obtain a valid definition of the topological charge and\nsusceptibility and we argue that all valid definitions are highly correlated\nand allow good control over topology on the lattice."
    },
    {
        "anchor": "Lattice study of the scalar and baryon spectra in many-flavor QCD: In the search for a composite Higgs boson in walking technicolor models, many\nflavor QCD, in particular with $N_f=8$, is an attractive candidate, and has\nbeen found to have a composite flavor-singlet scalar as light as the pion.\nBased on lattice simulations of this theory with the HISQ action, we will\npresent our preliminary results on the scalar decay constant using the\nfermionic bilinear operator, and on the mass of the lightest baryon state which\ncould be a dark matter candidate. Combining these two results, implications for\ndark matter direct detection are also discussed.",
        "positive": "Lattice simulation of $SU(2)$ dark glueball with machine learning: We study the mass and scattering cross section of $SU(2)$ glueballs as dark\nmatter candidates using lattice simulations. We employ both naive and improved\n$SU(2)$ gauge actions in $3+1$ dimensions with several $\\beta$ values, and\nadopt both the tranditional Monte Carlo method and the flow-based model based\non machine learning techniques to generate lattice configurations. The mass of\nthe scalar glueball with $J^{PC}=0^{++}$ and the NBS wave function are\ncalculated. Using the Runge-Kutta method, we extract the glueball interaction\npotential and scattering cross section. From the observational constraints, we\nobtain the lower bound of the mass of scalar glueball candidates as potential\ncomponents of dark matter."
    },
    {
        "anchor": "Hadron Mass Extraction from Lattice QCD: The extraction of quantities from lattice QCD calculations at realistic quark\nmasses is of considerable importance. Whilst physical quark masses are some way\noff, the recent advances in the calculation of hadron masses within full QCD\nnow invite improved extrapolation methods. We show that, provided the correct\nchiral behaviour of QCD is respected in the extrapolation to realistic quark\nmasses, one can indeed obtain a fairly reliable determination of masses, the\nsigma commutator and the J parameter. We summarise these findings by presenting\nthe nonanalytic behaviour of nucleon and rho masses in the standard Edinburgh\nplot.",
        "positive": "P-wave Radial distributions of a Heavy-light meson on a lattice: This is a follow-up to our earlier work for the charge (vector) and matter\n(scalar) distributions for S-wave states in a heavy-light meson, where the\nheavy quark is static and the light quark has a mass about that of the strange\nquark. The calculation is again carried out with dynamical fermions on a\n16^3x24 lattice with a lattice spacing of about 0.14 fm. It is shown that\nseveral features of the S- and P-wave distributions are in qualitative\nagreement with what one expects from a simple one-body Dirac equation\ninterpretation."
    },
    {
        "anchor": "With missing title of the paper. Overrelaxation Algorithm for coupled\n  Gauge-Higgs systems: In this letter we extent the overrelaxation algorithm, known to be very\nefficient in gauge theories, to coupled gauge-Higgs systems with a particular\nemphasis on the update of the radial mode of the Higgs field. Our numerical\ntests of the algorithm show that the autocorrelation times can be reduced\nsubstantially.",
        "positive": "Leading isospin breaking effects in the HVP contribution to $a_\u03bc$\n  and to the running of $\u03b1$: The anomalous magnetic moment of the muon $a_{\\mu}$ and the running of the\nelectromagnetic coupling $\\alpha$ play a fundamental role in beyond Standard\nModel (SM) physics searches. Non-perturbative hadronic contributions to both\nquantities, which are related to the hadronic vacuum polarization (HVP)\nfunction consisting of two electromagnetic currents, are a main source of\nuncertainty in the SM prediction. We compute the HVP function in lattice\nQCD+QED applying the time-momentum representation method. We expand the\nrelevant correlation functions around the isosymmetric limit. In particular, we\nfocus on leading isospin breaking effects taking quark-connected contributions\ninto account, which we evaluate on isosymmetric $N_{\\mathrm{f}}=2+1$ QCD gauge\nensembles generated by the CLS initiative with non-perturbatively\n$O(a)$-improved Wilson fermions."
    },
    {
        "anchor": "Modeling the Landau-Gauge Ghost Propagator in 2, 3 and 4 Space-Time\n  Dimensions: We present an analytic description of numerical results for the ghost\npropagator G(p^2) in minimal Landau gauge on the lattice. The data were\nproduced in the SU(2) case using the largest lattice volumes to date, for d =\n2, 3 and 4 space-time dimensions. Our proposed form for G(p^2) is derived from\nthe one-loop relation between ghost and gluon propagators, considering a\ntree-level ghost-gluon vertex and our previously obtained gluon-propagator\nresults \\cite{Cucchieri:2011ig}. Although this one-loop expression is not a\ngood description of the data, it leads to a one-parameter fit of our\nghost-propagator data with a generally good value of \\chi^2/dof, comparable to\nother fitting forms used in the literature. At the same time, we present a\nsimple parametrization of the difference between the lattice data and the\none-loop predictions.",
        "positive": "Systematic effects of the quenched approximation on the strong penguin\n  contribution to epsilon'/epsilon: We discuss the implementation and properties of the quenched approximation in\nthe calculation of the left-right, strong penguin contributions (i.e. Q_6) to\nepsilon'/epsilon. The coefficient of the new chiral logarithm, discovered by\nGolterman and Pallante, which appears at leading order in quenched chiral\nperturbation theory is evaluated using both the method proposed by those\nauthors and by an improved approach which is free of power divergent\ncorrections. The result implies a large quenching artifact in the contribution\nof Q_6 to epsilon'/epsilon. This failure of the quenched approximation affects\nonly the strong penguin operators and so does not affect the Q_8 contribution\nto epsilon'/epsilon nor Re A_0, Re A_2 and thus the Delta I=1/2 rule at tree\nlevel in chiral perturbation theory."
    },
    {
        "anchor": "Lattice study of 4d {\\cal N}=1 super Yang-Mills theory with dynamical\n  overlap gluino: We report on a lattice simulation result for four-dimensional {\\cal N}=1\nSU(2) super Yang-Mills theory with the dynamical overlap gluino. We study the\nspectrum of the overlap Dirac operator at three different gluino masses m=0.2,\n0.1 and 0.05 with the Iwasaki action on a 8^3 \\times 16 lattice. We find that\nthe lowest eigenvalue distributions are in good agreement with the prediction\nfrom the random matrix theory. Moreover the mass dependence of the condensate\nis almost constant, which gives a clean chiral limit. Our results for the\ngluino condensate in the chiral limit is < \\bar{\\psi} \\psi > r_0^3 = 0.63(12),\nwhere r_0 is the Sommer scale.",
        "positive": "Phase diagram of non-degenerate Wilson and twisted mass fermions: In this talk we determine the phase diagram and pion spectrum for Wilson and\ntwisted-mass fermions in the presence of non-degeneracy between the up and down\nquark and discretization errors. We find that the CP-violating phase of the\ncontinuum theory, which occurs for sufficiently large non-degeneracy, is\ncontinuously connected to the Aoki phase found in the lattice theory with\ndegenerate quarks. Both for the Aoki and first-order scenarios, this results in\na critical surface along which at least one of the pions is massless. In the\npion spectrum, we focus mainly on the untwisted case, where there is\ncompetition between the effects of non-degeneracy and discretization errors. A\nmore extensive analysis can be found in our recent paper [11]."
    },
    {
        "anchor": "Two dimensional lattice Gross--Neveu model with domain-wall fermions: We investigate the two dimensional lattice Gross--Neveu model in large flavor\nnumber limit using the domain-wall fermion formulation, as a toy model of\nlattice QCD. We study nonperturbative behaviorn of the restoration of chiral\nsymmetry of the domain-wall fermions as the extent of the extra dimension\n$(N_s)$ is increased to infinity. We find the the parity broken phase (Aoki\nphase) for finite $N_s$, and study the phase diagram, which is related to the\nmechanism of the chiral restoration in $N_s\\to\\infty$ limit. The continuum\nlimit is taken and $O(a)$ scaling violation of observables vanishes in\n$N_s\\to\\infty$ limit. We also examine the systematic dependencies of\nobservables to the parameters.",
        "positive": "Gapless Dirac Spectrum at High Temperature: Using the overlap Dirac operator I show that, contrary to some expectations,\neven well above the critical temperature there is not necessarily a gap in the\nDirac spectrum in pure SU(2) gauge theory. This happens when the Polyakov loop\nand the fermion boundary condition combine to give close to periodic boundary\ncondition for the fermions in the time direction. In this Polyakov loop sector\nthere is a non-vanishing density of Dirac eigenvalues around zero which implies\nthat chiral symmetry is spontaneously broken. I demonstrate this both directly\nand also by finding good agreement with the random matrix theory prediction for\nthe distribution of the lowest Dirac eigenvalue. I show that the chiral\ncondensate increases with the temperature therefore it is very unlikely to be\nexplained by topological fluctuations that become rapidly smaller above T_c.\nFinally I show that it is only a small fraction of the lowest Dirac eigenvalues\nthat decide which Polyakov loop sector is favored by the fermion determinant if\ndynamical fermions are turned on. This provides a qualitative understanding of\nhow the loss of confinement above T_c implies the restoration of chiral\nsymmetry."
    },
    {
        "anchor": "Scaling and Quantum Geometry in 2d Gravity: We review the status of understanding of the fractal structure of the quantum\nspacetime of 2d gravity coupled to conformal matter with c <= 1, with emphasis\nput on the results obtained last year.",
        "positive": "Finite-volume effects in moving frames: We determine the quantization condition for the energy levels of two\ninteracting particles in a finite box in a ``moving frame'', i.e. one in which\nthe total momentum of pions is non-zero. This condition is valid up to\ncorrections which fall exponentially withe the box size, and holds only below\nthe inelastic threshold. It is derived using field theoretic methods, using a\ngeneralization of previous summation formulae relating sums and integrals over\nmomenta. The result agrees with that obtained earlier by Rummakainen and\nGottlieb using a relativistic quantum mechanical approach. Technically, we\nexpand the finite-volume four-point Green function in terms of the\ninfinite-volume Bethe-Salpeter kernel, and determine the position of the poles.\nThe final result is written in terms of the two-pion scattering phase shift.\nOur result can be used to facilitate the determination of the scattering phase\nshift, and can be used to generalize the Lellouch-L\\\"uscher formula relating\nfinite-volume two-particle matrix elements to those in infinite volume."
    },
    {
        "anchor": "State mixing and masses of the $\u03c0^0$, $\u03b7$ and $\u03b7^\\prime$ mesons\n  from $n_f=1+1+1$ lattice QCD+QED: We present a lattice analysis of the light pseudoscalar mesons with\nconsideration for the mixing between the flavour-neutral states $\\pi^0$, $\\eta$\nand $\\eta^\\prime$. We extract the masses and flavour compositions of the\npseudoscalar meson nonet in $n_f=1+1+1$ lattice QCD+QED around an SU(3)-flavour\nsymmetric point, and observe flavour-symmetry features of the extracted data,\nalong with preliminary extrapolation results for the flavour compositions at\nthe physical point. A key result of this work is the observed mass splitting\nbetween the $\\pi^0$ and $\\eta$ on our ensembles, which is found to exhibit\nbehaviour that is simply related to the corresponding flavour compositions.",
        "positive": "Topological Summation of Observables Measured with Dynamical Overlap\n  Fermions: HMC histories for light dynamical overlap fermions tend to stay in a fixed\ntopological sector for many trajectories, so that the different sectors are not\nsampled properly. Therefore the suitable summation of observables, which have\nbeen measured in separate sectors, is a major challenge. We explore several\ntechniques for this issue, based on data for the chiral condensate and the\n(analogue of the) pion mass in the 2-flavour Schwinger model with dynamical\noverlap-hypercube fermions."
    },
    {
        "anchor": "Generalized Ginsparg-Wilson relations: We give a general derivation of Ginsparg-Wilson relations for both Dirac and\nMajorana fermions in any dimension. These relations encode continuous and\ndiscrete chiral, parity and time reversal anomalies and will apply to the\nvarious classes of free fermion topological insulators and superconductors (in\nthe framework of a relativistic quantum field theory in Euclidean spacetime).\nWe show how to formulate the exact symmetries of the lattice action and the\nrelevant index theorems for the anomalies.",
        "positive": "The static energy of a quark-antiquark pair from Laplacian eigenmodes: We test a method for computing the static quark-antiquark potential in\nlattice QCD, which is not based on Wilson loops, but where the trial states are\nformed by eigenvector components of the covariant lattice Laplace operator. The\nruntime of this method is significantly smaller than the standard Wilson loop\ncalculation, when computing the static potential not only for on-axis, but also\nfor many off-axis quark-antiquark separations, i.e., when a fine spatial\nresolution is required. We further improve the signal by using multiple\neigenvector pairs, weighted with Gaussian profile functions of the eigenvalues,\nproviding a basis for a generalized eigenvalue problem (GEVP), as it was\nrecently introduced to improve distillation in meson spectroscopy. We show\nresults with the new method for the static potential with dynamical fermions\nand demonstrate its efficiency compared to traditional Wilson loop\ncalculations. The method presented here can also be applied to compute hybrid\nor tetra-quark potentials and to static-light systems."
    },
    {
        "anchor": "A New Approach to the Problem of Dynamical Quarks in Numerical\n  Simulations of Lattice QCD: Lattice QCD with an even number of degenerate quark flavours is shown to be a\nlimit of a local bosonic field theory. The action of the bosonic theory is real\nand bounded from below so that standard simulation algorithms can be expected\nto apply. The feasibility of such calculations is discussed, but no practical\ntests have yet been made.",
        "positive": "Scaling behavior of $f_{B}$ with NRQCD: We investigate the scaling behavior of the $B$ meson decay constant $f_B$ and\n$f_{B_{s}}$ at $\\beta$$=$$5.7, 5.9, 6.1$, employing the NRQCD heavy quark\naction and the clover light quark action. Mixing effect from dimension-4\noperator in the heavy-light axial-vector current is studied, and we find that\nthe $a$ dependence of $f_B$ is significantly reduced. Our preliminary result\nfor the decay constants in the quenched approximation is\n$f_{B}$$=$$162(^{+35}_{-18})$ MeV, $f_{B_{s}}$$=$$190(^{+40}_{-19})$ MeV, and\n$f_{B_{s}}/f_{B}$$=$$1.18(^{+6}_{-6})$."
    },
    {
        "anchor": "Scattering amplitudes from finite-volume spectral functions: A novel proposal is outlined to determine scattering amplitudes from\nfinite-volume spectral functions. The method requires extracting smeared\nspectral functions from finite-volume Euclidean correlation functions, with a\nparticular complex smearing kernel of width $\\epsilon$ which implements the\nstandard $i\\epsilon$-prescription. In the $L \\to \\infty$ limit these smeared\nspectral functions are therefore equivalent to Minkowskian correlators with a\nspecific time ordering to which a modified LSZ reduction formalism can be\napplied. The approach is presented for general $m \\to n$ scattering amplitudes\n(above arbitrary inelastic thresholds) for a single-species real scalar field,\nalthough generalization to arbitrary spins and multiple coupled channels is\nlikely straightforward. Processes mediated by the single insertion of an\nexternal current are also considered. Numerical determination of the\nfinite-volume smeared spectral function is discussed briefly and the interplay\nbetween the finite volume, Euclidean signature, and time-ordered\n$i\\epsilon$-prescription is illustrated perturbatively in a toy example.",
        "positive": "Moving NRQCD for B Form Factors at High Recoil: We derive the continuum and lattice tree-level moving NRQCD (mNRQCD) through\norder 1/m^2. mNRQCD is a generalization of NRQCD for dealing with hadrons with\nnonzero velocity u_mu. The quark's total momentum is written as P^mu=Mu^mu+k^mu\nwhere k^mu << Mu^mu is discretized and Mu^mu is treated exactly. Radiative\ncorrections to couplings on the lattice are discussed. mNRQCD is particularly\nuseful for calculating B->pi and B->D form factors since errors are similar at\nlow and high recoil."
    },
    {
        "anchor": "Linking $U(2)\\times U(2)$ to $O(4)$ model via decoupling: The nature of chiral phase transition of massless two flavor QCD depends on\nthe fate of flavor singlet axial symmetry $U_A(1)$ at the critical temperature\n($T_c$). Assuming that a finite $U_A(1)$ breaking remains at $T_c$, the\ncorresponding three dimensional effective theory is composed of four massless\nand four massive scalar fields. We study the renormalization group flow of the\neffective theory in the $\\epsilon$-expansion, using a mass dependent\nrenormalization scheme, and determine the region of the attractive basin\nflowing into the $O(4)$ fixed point with a focus on its dependence on the size\nof the $U_A(1)$ breaking. The result is discussed from a perspective of the\ndecoupling of massive fields. It is pointed out that, although the effective\ntheory inside the attractive basin eventually reaches the $O(4)$ fixed point,\nthe approaching rate, one of the universal exponents, is different from that of\nthe standard $O(4)$ model. We present the reason for this peculiarity, and\npropose a novel possibility for chiral phase transition in two-flavor QCD.",
        "positive": "Gribov horizon and Gribov copies effect in lattice Coulomb gauge: Following a recent proposal by Cooper and Zwanziger we investigate via\n$SU(2)$ lattice simulations the effect on the Coulomb gauge propagators and on\nthe Gribov-Zwanziger confinement mechanism of selecting the Gribov copy with\nthe smallest non-trivial eigenvalue of the Faddeev-Popov operator, i.e.~the one\nclosest to the Gribov horizon. Although such choice of gauge drives the ghost\npropagator towards the prediction of continuum calculations, we find that it\nactually overshoots the goal. With increasing computer time, we observe that\nGribov copies with arbitrarily small eigenvalues can be found. For such a\nmethod to work one would therefore need further restrictions on the gauge\ncondition to isolate the physically relevant copies, since e.g.~the Coulomb\npotential $V_C$ defined through the Faddeev-Popov operator becomes otherwise\nphysically meaningless. Interestingly, the Coulomb potential alternatively\ndefined through temporal link correlators is only marginally affected by the\nsmallness of the eigenvalues."
    },
    {
        "anchor": "Moments of Parton Distributions Functions from Lattice QCD at the\n  Physical Point: We present a Lattice QCD calculation of the second Mellin moments of the\nnucleon axial, vector and tensor parton distribution functions (PDFs). The\ncalculation is performed at the physical pion mass with two different lattice\nspacings, and includes both zero and non-zero nucleon momenta. In our\npreliminary analysis, we identify operators that greatly reduce excited-state\ncontamination.",
        "positive": "A filtering technique for the temporally reduced matrix of the Wilson\n  fermion determinant: The Wilson fermion determinant can be written in the form of a series\nexpansion in fugacity $\\xi=\\exp(\\mu/T)$, provided that the eigenmodes of the\ntemporally reduced operator are obtained. Since the calculation of all\neigenmodes rapidly becomes prohibitive for larger volumes, we develop a method\nto calculate only the low-energy eigenmodes of the reduced matrix using a\nmatrix filetering technique. This provides a basis for an approximation to\nneglect uninteresting ultraviolet contributions."
    },
    {
        "anchor": "The domain-wall model in an asymptotic-free dynamics: We investigate a possibility that the rough gauge problem, which have\nappeared to be a main reason for failures of lattice chiral gauge theories, is\ncured by an asymptotic-free dynamics. Taking the domain-wall model in 2(+1)\ndimensions with SU(2) gauge group, we carry out the quenched simulation of\ngauge fields in the extra dimension. By studying fermion spectra in several\nvolumes, we show that the chiral zero modes exist on the wall without having\nthe spontaneous symmetry breaking thanks to the asymptotic-free dynamics. This\nresult suggests that the rough gauge problem is solved in some class of lattice\nchiral fermions as well as in 4 dimensions if an asymptotic-free dynamics is\nincorporated.",
        "positive": "Abelian Monopoles and Action Density in SU(2) Gluodynamics on the\n  Lattice: We show that the extended Abelian magnetic monopoles in the Maximal Abelian\nprojection of lattice SU(2) gluodynamics are locally correlated with the\nmagnetic and the electric parts of the SU(2) action density. These correlations\nare observed in the confined and in the deconfined phases."
    },
    {
        "anchor": "Phase diagram of the quantum O(2)-model in 2+1 dimensions: The quantum O(2) model in 2+1 dimensions is studied by simulating the 3d O(2)\nmodel near criticality. Finite densities are introduced by a non-zero chemical\npotential mu, and the worm algorithm is used to circumvent the sign problem.\nThe renormalisation is discussed in some detail. We find that the onset value\nof the chemical potential coincides with the mass gap. The mu-dependence of the\ndensity rules out Bose-Einstein condensation and might be compatible with an\ninteracting Fermi gas. The mu-T phase diagram is explored using the density and\nthe magnetic susceptibility. In the cold, but dense regime of the phase\ndiagram, we find a superfluid phase.",
        "positive": "The Phase Diagram of Strong Coupling QCD including Gauge Corrections: The strong coupling limit of lattice QCD with staggered fermions has been\nstudied for decades, both via Monte Carlo and via mean field theory. In this\nmodel, the finite density sign problem can be made mild and the full phase\ndiagram can be obtained, even in the chiral limit. It is however desirable to\nunderstand the effect of a finite lattice gauge coupling $\\beta$ on the phase\ndiagram in the $\\mu-T$ plane in order to understand how it evolves into the\nphase diagram of continuum QCD. Here we discuss how to construct a partition\nfunction for non-zero lattice coupling, exact to $\\mathcal{O}(\\beta)$, and\npresent corresponding Monte Carlo results, in particular for corrections to the\nchiral susceptibility and to the phase diagram."
    },
    {
        "anchor": "Infrared properties of a prototype model for beyond-Standard Model\n  physics: We construct a prototype BSM model based on the SU(3) color gauge group and a\ncombination of 4 light (massless) and 8 heavy flavors. In the infrared, the\nSU(4) flavor chiral symmetry is spontaneously broken, while in the ultraviolet\nthis model exhibits the properties of the $N_f=12$ conformal fixed point.\nRenormalization group considerations predict the spectrum of such a system to\nshow hyperscaling, i.e. dimensionless ratios of hadron masses or decay\nconstants are independent of the heavy mass. Hyperscaling is present for bound\nstates of light, heavy, or a combination of heavy and light flavors and leads\nto a strongly predictive model. Despite chiral symmetry breaking, this system\nfeatures a spectrum exhibiting a very non-QCD like behavior. Furthermore, the\ngauge coupling becomes an irrelevant parameter. We support these expectations\nby presenting numerical results based on four different values of the heavy\nquark mass $am_h$, up to six different values of the light quark mass\n$am_\\ell$, and include, for the first time, preliminary data at a second value\nof the gauge coupling $\\beta$. Our model can be embedded in scenarios\ndescribing the Higgs boson either as a pseudo Nambu-Goldstone boson or a\ndilaton-like particle.",
        "positive": "The Kosterlitz-Thouless Universality Class: We examine the Kosterlitz-Thouless universality class and show that essential\nscaling at this type of phase transition is not self-consistent unless\nmultiplicative logarithmic corrections are included. In the case of specific\nheat these logarithmic corrections are identified analytically. To identify\nthose corresponding to the susceptibility we set up a numerical method\ninvolving the finite-size scaling of Lee-Yang zeroes. We also study the density\nof zeroes and introduce a new concept called index scaling. We apply the method\nto the XY-model and the closely related step model in two dimensions. The\ncritical parameters (including logarithmic corrections) of the step model are\ncompatable with those of the XY-model indicating that both models belong to the\nsame universality class. This result then raises questions over how a vortex\nbinding scenario can be the driving mechanism for the phase transition.\nFurthermore, the logarithmic corrections identified numerically by our methods\nof fitting are not in agreement with the renormalization group predictions of\nKosterlitz and Thouless."
    },
    {
        "anchor": "Spectrum of the Dirac Operator and Inversion Algorithms with Dynamical\n  Staggered Fermions: Complete spectra of the staggered Dirac operator $\\Dirac$ are determined in\nfour-dimensional $SU(2)$ gauge fields with and without dynamical fermions.\n  An attempt is made to relate the performance of multigrid and conjugate\ngradient algorithms for propagators with the distribution of the eigenvalues\nof~$\\Dirac$.",
        "positive": "Mass spectrum of $2$-dimensional $\\mathcal{N}=(2,2)$ super Yang-Mills\n  theory on the lattice: In the present work we analyse $\\mathcal{N}=(2,2)$ supersymmetric Yang-Mills\n(SYM) theory in two dimensions by means of lattice simulations. The theory\narises as dimensional reduction of $\\mathcal{N}=1$ SYM theory in four\ndimensions. As in other gauge theories with extended supersymmetry, the\nclassical scalar potential has flat directions which may destabilize numerical\nsimulations. In addition, the fermion determinant need not be positive and this\nsign-problem may cause further problems in a stochastic treatment. We\ndemonstrate that $\\mathcal{N}=(2,2)$ super Yang-Mills theory has actually no\nsign problem and that the flat directions are lifted and thus stabilized by\nquantum corrections. Only the bare mass of the scalars experience a finite\nadditive renormalization in this finite theory. On various lattices with\ndifferent lattice constants we determine the scalar masses and hopping\nparameters for which the supersymmetry violating terms are minimal. By studying\nfour Ward identities and by monitoring the $\\pi$-mass we show that\nsupersymmetry is indeed restored in the continuum limit. In the second part we\ncalculate the masses of the low-lying bound states. We find that in the\ninfinite-volume and supersymmetric continuum limit the Veneziano-Yankielowicz\nsuper-multiplet becomes massless and the Farrar-Gabadadze-Schwetz\nsuper-multiplet decouples from the theory. In addition, we estimate the masses\nof the excited mesons in the Veneziano-Yankielowicz multiplet. We observe that\nthe gluino-glueballs have comparable masses to the excited mesons."
    },
    {
        "anchor": "Index and overlap construction for staggered fermions: Recent developments regarding index and overlap construction for staggered\nfermions are reviewed, highlighting the surprising and unexpected aspects.",
        "positive": "Equation of state at finite density in two-flavor QCD with improved\n  Wilson quarks: We study the equation of state in two-flavor QCD at finite temperature and\ndensity. Simulations are made with the RG-improved gluon action and the\nclover-improved Wilson quark action. Along the lines of constant physics for\n$m_{\\rm PS}/m_{\\rm V} = 0.65$ and 0.80, we compute the derivatives of the quark\ndeterminant with respect to the quark chemical potential $\\mu_q$ up to the\nfourth order at $\\mu_q=0$. We adopt several improvement techniques in the\nevaluation. We study thermodynamic quantities and quark number susceptibilities\nat finite $\\mu_q$ using these derivatives. We find enhancement of the quark\nnumber susceptibility at finite $\\mu_q$, in accordance with previous\nobservations using staggered-type quarks. This suggests the existence of a\nnearby critical point."
    },
    {
        "anchor": "Ab-initio study of dibaryons with highest bottom number: We present the first lattice study of dibaryons with highest bottom number.\nUtilizing a set of state-of-the-art lattice QCD ensembles and methodologies, we\ndetermine the ground state of dibaryon composed of two $\\Omega_{bbb}$ baryons.\nWe extract the related scattering amplitude in the $^1S_0$ channel and find a\nsub-threshold pole, which signifies an unambiguous evidence for a deeply bound\n$\\Omega_{bbb}-\\Omega_{bbb}$ dibaryon. The binding energy of such a state as\ndictated by this pole singularity is found to be -81($^{+14}_{-16}$) MeV. We\nquantify various systematic uncertainties involved in this determination,\nincluding those related to the excited state contamination and Coulomb\nrepulsion between the bottom quarks.",
        "positive": "An exact representation of the fermion dynamics in terms of Poisson\n  processes: We present a simple derivation of a Feynman-Kac type formula to study\nfermionic systems. In this approach the real time or the imaginary time\ndynamics is expressed in terms of the evolution of a collection of Poisson\nprocesses. A computer implementation of this formula leads to a family of\nalgorithms parametrized by the values of the jump rates of the Poisson\nprocesses. From these an optimal algorithm can be chosen which coincides with\nthe Green Function Monte Carlo (GFMC) method in the limit when the latter\nbecomes exact."
    },
    {
        "anchor": "Probing the proton and its excitations in full QCD: We present a first look at the application of variational techniques for the\nextraction of the electromagnetic properties of an excited nucleon system. In\nparticular, we include preliminary results for charge radii and magnetic\nmoments of the proton, its first even-parity excitation and the $\\Delta^{+}$.",
        "positive": "The spectrum of charmonium-like vector mesons in lattice QCD: We present the first lattice results of the spectrum of exotic vector mesons\nextracted from the molecular and diquark-antidiquark operators, with quark\nfields c-q-cbar-qbar, and c-s-cbar-qbar (c-q-cbar-sbar) respectively, in\nlattice QCD with exact chiral symmetry. Our results suggest that X(3872) and\nY(4260) are in the spectrum of QCD, with J^{PC} = 1^{++} and 1^{--}\nrespectively. Moreover, we obtain the spectrum of heavier exotic mesons with\nc-s-cbar-ubar (c-u-cbar-sbar), c-s-cbar-dbar (c-d-cbar-sbar), c-s-cbar-sbar,\nand c-c-cbar-cbar, as the first theoretical predictions from lattice QCD."
    },
    {
        "anchor": "Kinematics of Multigrid Monte Carlo: We study the kinematics of multigrid Monte Carlo algorithms by means of\nacceptance rates for nonlocal Metropolis update proposals. An approximation\nformula for acceptance rates is derived. We present a comparison of different\ncoarse-to-fine interpolation schemes in free field theory, where the formula is\nexact. The predictions of the approximation formula for several interacting\nmodels are well confirmed by Monte Carlo simulations. The following rule is\nfound: For a critical model with fundamental Hamiltonian H(phi), absence of\ncritical slowing down can only be expected if the expansion of <H(phi + psi)>\nin terms of the shift psi contains no relevant (mass) term. We also introduce a\nmultigrid update procedure for nonabelian lattice gauge theory and study the\nacceptance rates for gauge group SU(2) in four dimensions.",
        "positive": "Testing mixed action approaches to meson spectroscopy with twisted mass\n  sea quarks: We explore and compare three mixed action setups with Wilson twisted mass sea\nquarks and different valence quark actions: (1) Wilson twisted mass, (2) Wilson\ntwisted mass + clover and (3) Wilson + clover. Our main goal is to reduce\nlattice discretization errors in mesonic spectral quantities, in particular to\nreduce twisted mass parity and isospin breaking."
    },
    {
        "anchor": "Form factors in lattice QCD: Lattice simulations of QCD have produced precise estimates for the masses of\nthe lowest-lying hadrons which show excellent agreement with experiment. By\ncontrast, lattice results for the vector and axial vector form factors of the\nnucleon show significant deviations from their experimental determination. We\npresent results from our ongoing project to compute a variety of form factors\nwith control over all systematic uncertainties. In the case of the pion\nelectromagnetic form factor we employ partially twisted boundary conditions to\nextract the pion charge radius directly from the linear slope of the form\nfactor near vanishing momentum transfer. In the nucleon sector we focus\nspecifically on the possible contamination from contributions of higher excited\nstates. We argue that summed correlation functions offer the possibility of\neliminating this source of systematic error. As an illustration of the method\nwe discuss our results for the axial charge, gA, of the nucleon.",
        "positive": "A one-loop study of matching conditions for static-light flavor currents: Heavy Quark Effective Theory (HQET) computations of semi-leptonic decays,\ne.g. B -> pi l nu, require the knowledge of the parameters in the effective\ntheory for all components of the heavy-light flavor currents. So far\nnon-perturbative matching conditions have been employed only for the time\ncomponent of the axial current. Here we perform a check of matching conditions\nfor the time component of the vector current and the spatial component of the\naxial vector current up to one-loop order of perturbation theory and to lowest\norder of the 1/m-expansion. We find that the proposed observables have small\nhigher order terms in the 1/m-series and are thus excellent candidates for a\nnon-perturbative matching procedure."
    },
    {
        "anchor": "Dynamical Quark Effects on Light Quark Masses: We present results for light quark masses from a systematic lattice QCD study\nwith two degenerate flavors of dynamical quarks. Simulations are made with a\nrenormalization-group improved gauge action and a mean-field improved clover\nquark action for sea quark masses corresponding to $m_{\\rm PS}/m_{\\rm V}\n\\approx 0.8$--0.6 and the lattice spacing $a=0.22$--0.11 fm. In the continuum\nlimit we find $m_{ud}^{\\bar{MS}}(2 {\\rm GeV})=3.44^{+0.14}_{-0.22}$ MeV using\nthe $\\pi$ and $\\rho$ meson masses as physical input, and $m_s^{\\bar{MS}}(2 {\\rm\nGeV})=88^{+4}_{-6}$ MeV or $90^{+5}_{-11}$ MeV with the $K$ or $\\phi$ meson\nmass as additional input. The quoted errors represent statistical and\nsystematic combined, the latter including those from continuum and chiral\nextrapolations, and from renormalization factors. Compared to quenched results,\ntwo flavors of dynamical quarks reduce quark masses by about 25%.",
        "positive": "Wilson fermions with chirally twisted mass: Lattice formulations of QCD with Wilson fermions and a chirally twisted quark\nmass matrix provide an attractive framework for non-perturbative numerical\nstudies. Owing to reparameterization invariance, the limiting continuum theory\nis just QCD. No spurious quark zero modes, which are responsible for the\nproblem with exceptional configurations, can occur at finite values of the\nquark mass. Moreover, the details of the lattice formulation can be adjusted so\nas to simplify the renormalization and the O($a$) improvement of several\nquantities of phenomenological relevance. The first exploratory studies in the\nquenched approximation yield very encouraging results."
    },
    {
        "anchor": "Cutoff effects in twisted mass lattice QCD: We present a first numerical study of lattice QCD with O(a) improved Wilson\nquarks and a chirally twisted mass term. Renormalized correlation functions are\nderived from the Schroedinger functional and evaluated in an intermediate\nspace-time volume of size 0.75^3 x 1.5 fm^4. In the quenched approximation\nprecise results are then obtained with a moderate computational effort,\nallowing for a detailed study of the continuum approach. The latter is\ndiscussed in terms of observables which converge to meson masses and decay\nconstants in the limit of large space-time volume. In the O(a) improved theory\nwe find residual cutoff effects to be at the level of a few percent for lattice\nspacings of about 0.1 fm.",
        "positive": "Fermions as global correction in lattice QCD: The fermion determinant is a highly non-local object and its logarithm is an\nextensive quantity. For these reasons it is widely believed that the\ndeterminant cannot be treated in acceptance steps of gauge link configurations\nthat differ in a large fraction of the links. However, for exact factorisations\nof the determinant that separate the ultraviolet from the infra-red modes of\nthe Dirac operator it is known that the latter show less variation under\nchanges of the gauge field compared to the former. Using a factorisation based\non recursive domain decomposition allows for a hierarchical algorithm that\nstarts with pure gauge updates of the links within the domains and ends after a\nnumber of filters with a global acceptance step. We find that the global\nacceptance rate is high on moderate lattice sizes. Whether this type of\nalgorithm can help in curing the problem of critical slowing down is presently\nunder study."
    },
    {
        "anchor": "Low lying charmonium states at the physical point: We present results for the mass splittings of low-lying charmonium states\nfrom a calculation with Wilson clover valence quarks with the Fermilab\ninterpretation on an asqtad sea. We use five lattice spacings and two values of\nthe light sea quark mass to extrapolate our results to the physical point.\nSources of systematic uncertainty in our calculation are discussed and we\ncompare our results for the 1S hyperfine splitting, the 1P-1S splitting and the\nP-wave spin orbit and tensor splittings to experiment.",
        "positive": "Recent progress on nucleon form factors: The form factors of the nucleon provide key information on nucleon\nproperties. When confronted with precisely measured observables from\nexperiments, they serve as benchmark quantities for lattice calculations. On\nthe other hand lattice determinations may serve as vital theory input for the\ninterpretation of experiments, e.g. in neutrino-nucleus scattering. I review\nrecent progress in the calculation of nucleon form factors on the lattice and\nits relevance to future experiments."
    },
    {
        "anchor": "The eta mass and NNLO Three-Flavor Partially Quenched Chiral\n  Perturbation Theory: We show how to resum neutral propagators to all orders in Partially Quenched\nChiral Perturbation Theory. We calculate the relevant quantities to\nnext-to-next-to-leading order (NNLO). Using these results we show how to extend\nthe proposal by Sharpe and Shoresh for determining the parameters relevant for\nthe eta mass from partially quenched lattice QCD calculations to NNLO.",
        "positive": "External Momentum, Volume Effects, and the Nucleon Magnetic Moment: We analyze the determination of volume effects for correlation functions that\ndepend on an external momentum. As a specific example, we consider finite\nvolume nucleon current correlators, and focus on the nucleon magnetic moment.\nBecause the multipole decomposition relies on SO(3) rotational invariance, the\nstructure of such finite volume corrections is unrelated to infinite volume\nmultipole form factors. One can deduce volume corrections to the magnetic\nmoment only when a zero-mode photon coupling vanishes, as occurs at\nnext-to-leading order in heavy baryon chiral perturbation theory. To deduce\nsuch finite volume corrections, however, one must assume continuous momentum\ntransfer. In practice, volume corrections with momentum transfer dependence are\nrequired to address the extraction of the magnetic moment, or other observables\nthat arise in momentum dependent correlation functions. Additionally we shed\nsome light on a puzzle concerning differences in lattice form factor data at\nequal values of momentum transfer squared."
    },
    {
        "anchor": "Localization of lattice fermions: lessons for overlap: Lattice fermions in a fluctuating gauge field can show localization, much\nlike electrons in a disordered potential. We study the spectrum of localized\nand extended states of supercritical Wilson fermions in gauge ensembles\ngenerated with plaquette and improved actions. When the Wilson fermion operator\nis used to construct the overlap kernel, the mobility edge, that is the\nboundary between the localized and extended states, determines the range of the\nkernel.",
        "positive": "Lattice QCD at finite baryon density using analytic continuation: We simulate lattice QCD with two flavors of Wilson fermions at imaginary\nbaryon chemical potential. Results for the baryon number density computed in\nthe confining and deconfining phases at imaginary baryon chemical potential are\nused to determine the baryon number density and higher cumulants at the real\nchemical potential via analytical continuation."
    },
    {
        "anchor": "Investigating the topological structure of quenched lattice QCD with\n  overlap fermions by using multi-probing approximation: The topological charge density and topological susceptibility are determined\nby multi-probing approximation using overlap fermions in quenched SU(3) gauge\ntheory. Then we investigate the topological structure of the quenched QCD\nvacuum, and compare it with results from the all-scale topological density, the\nresults are consistent. Random permuted topological charge density is used to\ncheck whether these structures represent underlying ordered properties.\nPseudoscalar glueball mass is extracted from the two-point correlation function\nof the topological charge density. We study $3$ ensembles of different lattice\nspacing $a$ with the same lattice volume $16^{3}\\times32$, the results are\ncompatible with the results of all-scale topological charge density, and the\ntopological structures revealed by multi-probing are much closer to all-scale\ntopological charge density than that by eigenmode expansion.",
        "positive": "Thermodynamics of 1-flavor QCD: We present first results, for heavy to moderate quark masses, of a study of\nthermodynamic properties of 1-flavor QCD, using the multiboson algorithm."
    },
    {
        "anchor": "Nucleon generalized form factors with twisted mass fermions: We present results on the nucleon form factors, momentum fraction and\nhelicity moment for $N_f=2$ and $N_f=2+1+1$ twisted mass fermions for a number\nof lattice volumes and lattice spacings. First results for a new $N_f=2$\nensemble at the physical pion mass are also included. The implications of these\nresults on the spin content of the nucleon are discussed taking into account\nthe disconnected contributions at one pion mass.",
        "positive": "Negative moment of inertia and rotational instability of gluon plasma: Using first-principle numerical simulations of the lattice SU(3) gauge\ntheory, we calculate the isothermal moment of inertia of the rigidly rotating\ngluon plasma. We find that the moment of inertia unexpectedly takes a negative\nvalue below the \"supervortical temperature\" $T_s = 1.50(10) T_c$, vanishes at\n$T = T_s$, and becomes a positive quantity at higher temperatures. The negative\nmoment of inertia indicates a thermodynamic instability of rigid rotation. We\nderive the condition of thermodynamic stability of the vortical plasma and show\nhow it relates to the scale anomaly and the magnetic gluon condensate. The\nrotational instability of gluon plasma shares a striking similarity with the\nrotational instabilities of spinning Kerr and Myers-Perry black holes."
    },
    {
        "anchor": "Lattice studies of the $Sp(4)$ gauge theory with two fundamental and\n  three antisymmetric Dirac fermions: We consider the $Sp(4)$ gauge theory coupled to $N_f=2$ fundamental and\n$n_f=3$ antisymmetric flavours of Dirac fermions in four dimensions. This\ntheory serves as the microscopic origin for composite Higgs models with\n$SU(4)/Sp(4)$ coset, supplemented by partial top compositeness. We study\nnumerically its lattice realisation, and couple the fundamental plaquette\naction to Wilson-Dirac fermions in mixed representations, by adopting a\n(rational) hybrid Monte Carlo method, to perform non-trivial tests of the\nproperties of the resulting lattice theory.\n  We find evidence of a surface (with boundaries) of first-order bulk phase\ntransitions in the three-dimensional space of bare parameters (one coupling and\ntwo masses). Explicit evaluation of the Dirac eigenvalues confirms the expected\npatterns of global symmetry breaking. After investigating finite volume effects\nin the weak-coupling phase of the theory, for the largest available lattice we\nstudy the mass spectra of the lightest spin-0 and spin-1 flavoured mesons\ncomposed of fermions in each representation, and of the lightest half-integer\nspin composite particle made of fermions in different representations -- the\nchimera baryon. This work sets the stage for future systematical studies of the\nnon-perturbative dynamics in phenomenologically relevant regions of parameter\nspace.",
        "positive": "Multi-point Pad\u00e8 for the study of phase transitions: from the Ising\n  model to lattice QCD: The Bielefeld Parma collaboration has recently put forward a method to\ninvestigate the QCD phase diagram based on the computation of Taylor series\ncoefficients at both zero and imaginary values of the baryonic chemical\npotential. The method is based on the computation of multi-point Pad\\`e\napproximants. We review the methodological aspects of the computation and, in\norder to gain confidence in the approach, we report on the application of the\nmethod to the two-dimensional Ising model (probably the most popular arena for\ntesting tools in the study of phase transitions). Besides showing the\neffectiveness of the multi-point Pad\\`e approach, we discuss what these results\ncan suggest in view of further progress in the study of the QCD phase diagram.\nWe finally report on very preliminary results in which we look for Pad\\`e\napproximants at different temperatures and fixed values of the (imaginary)\nbaryonic chemical potential."
    },
    {
        "anchor": "TKNN formula for general lattice Hamiltonian in odd dimensions: Topological insulators in odd dimensions are characterized by topological\nnumbers. We prove the well-known relation between the topological number given\nby the Chern character of the Berry curvature and the Chern-Simons level of the\nlow energy effective action for a general class of Hamiltonians bilinear in the\nfermion with general U(1) gauge interactions including non-minimal couplings by\nan explicit calculation. A series of Ward-Takahashi identities are crucial to\nrelate the Chern-Simons level to a winding number, which could then be directly\nreduced to Chern character of Berry curvature by carrying out the integral over\nthe temporal momenta.",
        "positive": "Instanton effects on chiral symmetry breaking and hadron spectroscopy: This project aims to give indications to find monopole and instanton effects\nin QCD on the observables by experiments. First, we add the monopole and\nanti-monopole to the QCD vacuum of the quenched SU(3) and calculate the\nphysical observables using the eigenvalues and eigenvectors of the overlap\nDirac operator that preserves the exact chiral symmetry. We have found that the\nadditional monopole and anti-monopole make the long monopole loops are closely\nrelated to the quark confinement without changing the vacuum structure.\nFurthermore, we have confirmed that the additional monopole and anti-monopole\ncreate instantons and anti-instantons are closely associated with the chiral\nsymmetry breaking. We have shown that the chiral condensate (minus value)\ndecreases in direct proportion to the square root of the number density of the\ninstantons and anti-instantons. The decay constants and masses of pion and kaon\nincrease in direct proportion to the one-fourth root of the number density of\nthe instantons and anti-instantons. This report estimates the eta meson mass\nusing these outcomes as the input values, and the eta-prime meson mass is\ncalculated in two ways: (i) Substituting the numerical results of the\ntopological charge and pion decay constant to the Witten and Veneziano mass\nformula. (ii) Calculating the correlations of the disconnected (hairpin)\ngraphs. The preliminary results of the eta-prime meson mass estimated in the\nquenched SU(3) are as follows. (i) m$_{\\eta'}$ = 1.055(15)$\\times10^{3}$ [MeV]\n(at the continuum limit). (ii) m$_{\\eta'}$ = 1.04(2)$\\times10^{3}$ [MeV] (at\nthe chiral and continuum limits). Finally, we demonstrate that the eta-prime\nmeson mass becomes heavy with increasing the number density of the instantons\nand anti-instantons."
    },
    {
        "anchor": "Five-dimensional Gauge Theories in a warped background: The phase diagram of five-dimensional anisotropic gauge theories in a flat\nbackground has been extensively explored during the last decade. Here, we\npresent novel results for the phase structure of the five-dimensional\nanisotropic SU(2) model embedded in a warped background. The static potential\nin the deconfining region of the phase diagram, close to the transition to the\nlayered phase, provides evidence of a Yukawa mass, suggesting that the system\nis in a 4D Higgs-like phase. As no symmetry has been broken by the boundary\nconditions, this phase appears to be due to the warp factor. Whether the system\nis dimensionally reduced from a 5D phase to this 4D Higgs-like phase, which\nwould provide a mechanism for dimensional reduction via localization, remains\nopen.",
        "positive": "Finite volume effects using lattice chiral perturbation theory: Lattice regularization is used to perform chiral perturbation theory\ncalculations in finite volume. The lattice spacing is chosen small enough to be\nirrelevant, and numerical results are obtained from simple summations."
    },
    {
        "anchor": "Construction of $bb\\bar{u}\\bar{d}$ tetraquark states on lattice with\n  NRQCD bottom and HISQ up/down quarks: We construct $bb\\bar{u}\\bar{d}$ states on lattice using NRQCD action for\nbottom and HISQ action for the light up/down quarks. The NRQCD-HISQ tetraquark\noperators are constructed for \"bound\" $[bb][\\bar{u}\\bar{d}]$ and \"molecular\"\n$[b\\bar{u}] [b\\bar{d}]$ states. Corresponding to these different operators, two\ndifferent appropriately tuned light quark masses are needed to obtain the\ndesired spectra. We explain this requirement of different $m_{u/d}$ in the\nlight of relativised quark model involving Hartree-Fock calculation. The mass\nspectra of double bottom tetraquark states are obtained on MILC $N_f=2+1$\nAsqtad lattices at three different lattice spacings. Variational analysis has\nbeen carried out to obtain the relative contribution of \"bound\" and \"molecular\"\nstates to the energy eigenstates.",
        "positive": "The Phase Diagram of Two Color QCD: I present recent results from lattice simulations of SU(2) gauge theory with\nNf=2 Wilson quark flavors, at non-zero quark chemical potential. The\nthermodynamic equation of state is discussed along with the nature of the high\ndensity matter which forms. It is conjectured that deconfinement may mean\ndifferent things for bulk and Fermi surface phenomena."
    },
    {
        "anchor": "Leptonic decay constants f_Ds and f_D in three flavor lattice QCD: We determine the leptonic decay constants in three flavor unquenched lattice\nQCD. We use O(a^2)-improved staggered light quarks and O(a)-improved charm\nquarks in the Fermilab heavy quark formalism. Our preliminary results, based\nupon an analysis at a single lattice spacing, are f_Ds = 263(+5-9)(+/-24) MeV\nand f_D = 225(+11-13)(+/-21) MeV. In each case, the first reported error is\nstatistical while the is the combined systematic uncertainty.",
        "positive": "Truncated Determinant Approach to Light Dynamical Quarks: Virtual quark effects in lattice QCD are studied in an approach where the\ninfrared modes are included in a precise and gauge-invariant manner. At fixed\nphysical volume the required number of modes does not increase in the continuum\nlimit, and the acceptance is tolerable even for very light quark masses.\nTopological charge distributions at varying quark mass, and the static quark\npotential, showing the onset of string-breaking, are presented in both QED2 and\nQCD4."
    },
    {
        "anchor": "Can lattice data for two heavy-light mesons be understood in terms of\n  simply two-quark potentials?: By comparing lattice data for the two heavy-light meson system (Q^2 qbar^2)\nwith a standard many-body approach employing only interquark potentials, it is\nshown that the use of unmodified two-quark potentials leads to a gross\noverestimate of the binding energy.",
        "positive": "The scalar radius of the pion from Lattice QCD in the continuum limit: We extend our study of the pion scalar radius in two-flavour lattice QCD to\ninclude two additional lattice spacings as well as lighter pion masses,\nenabling us to perform a combined chiral and continuum extrapolation. We find\ndiscretisation artefacts to be small for the radius, and confirm the importance\nof the disconnected diagrams in reproducing the correct chiral behaviour. Our\nfinal result for the scalar radius of the pion at the physical point is\n$\\left\\langle r^2\\right\\rangle^\\pi_{\\rm S}=0.600\\pm0.052$ fm$^2$, corresponding\nto a value of $\\overline{\\ell}_4=4.54\\pm0.30$ for the low-energy constant\n$\\overline{\\ell}_4$ of NLO chiral perturbation theory."
    },
    {
        "anchor": "Finite Size Scaling, Fisher Zeroes and N=4 Super Yang-Mills: We investigate critical slowing down in the local updating continuous-time\nQuantum Monte Carlo method by relating the finite size scaling of Fisher Zeroes\nto the dynamically generated gap, through the scaling of their respective\ncritical exponents. As we comment, the nonlinear sigma model representation\nderived through the hamiltonian of our lattice spin model can also be used to\ngive a effective treatment of planar anomalous dimensions in N=4 SYM. We\npresent scaling arguments from our FSS analysis to discuss quantum corrections\nand recent 2-loop results, and further comment on the prospects of extending\nthis approach for calculating higher twist parton distributions.",
        "positive": "Vacuum structure as seen by overlap fermions: Three complementary views on the QCD vacuum structure, all based on\neigenmodes of the overlap operator, are reported in their interrelation: (i)\nspectral density, localization and chiral properties of the modes, (ii) the\npossibility of filtering the field strength with the aim to detect selfdual and\nantiselfdual domains and (iii) the various faces of the topological charge\ndensity, with and without a cutoff \\lambda_{\\rm cut} = O(\\Lambda_{QCD}). The\ntechniques are tested on quenched SU(3) configurations."
    },
    {
        "anchor": "The Polyakov loop models in the large N limit: Phase diagram at finite\n  density: The 't Hooft-Veneziano limit of various U(N) and SU(N) Polyakov loop models\nis constructed at finite temperature and non-zero baryon chemical potential. In\nthis paper we calculate the free energy, its derivatives, the Polyakov loop\nexpectation values and the baryon density. The phase diagram is described in\ndetails.",
        "positive": "Scattering in a Simple 2-d Lattice Model: L\\\"uscher has suggested a method to determine phase shifts from the finite\nvolume dependence of the two-particle energy spectrum. We apply this to two\nmodels in d=2: (a) the Ising model, (b) a system of two Ising fields with\ndifferent mass and coupled through a 3-point term, both considered in the\nsymmetric phase. The Monte Carlo simulation makes use of the cluster updating\nand reduced variance operator techniques. For the Ising system we study in\nparticular O($a^2$) effects in the phase shift of the 2-particle scattering\nprocess."
    },
    {
        "anchor": "Hadronic Physics from the Lattice: We present the lattice gauge theory approach to evaluating non-perturbative\nhadronic interactions from first principles. We discuss applications to\nglueballs, inter-quark potentials, the running coupling constant, the light\nhadron spectrum and the pseudoscalar decay constant $f_P$.",
        "positive": "Exploring strange nucleon form factors on the lattice: We discuss techniques for evaluating sea quark contributions to hadronic form\nfactors on the lattice and apply these to an exploratory calculation of the\nstrange electromagnetic, axial, and scalar form factors of the nucleon. We\nemploy the Wilson gauge and fermion actions on an anisotropic 24^3 x 64\nlattice, probing a range of momentum transfer with Q^2 < 1 GeV^2. The strange\nelectric and magnetic form factors, G_E^s(Q^2) and G_M^s(Q^2), are found to be\nsmall and consistent with zero within the statistics of our calculation. The\nlattice data favor a small negative value for the strange axial form factor\nG_A^s(Q^2) and exhibit a strong signal for the bare strange scalar matrix\nelement <N|ss|N>_0. We discuss the unique systematic uncertainties affecting\nthe latter quantity relative to the continuum, as well as prospects for\nimproving future determinations with Wilson-like fermions."
    },
    {
        "anchor": "Results in the static approximation: We present a comprehensive study of finite volume and lattice spacing effects\non observables calculated in the static approximation. Ground state projection\nusing smearing techniques is studied at $\\beta=6.26$. We give high statics\nresults for the pseudoscalar decay constant after extrapolating to the chiral\nand continuum limit. In addition results for mass splittings and the distance\nof string breaking in the $Q\\bar{Q}$ potential are presented.",
        "positive": "Higher order fluctuations and correlations of conserved charges from\n  lattice QCD: We calculate several diagonal and non-diagonal fluctuations of conserved\ncharges in a system of 2+1+1 quark flavors with physical masses, on a lattice\nwith size $48^3\\times12$. Higher order fluctuations at $\\mu_B=0$ are obtained\nas derivatives of the lower order ones, simulated at imaginary chemical\npotential. From these correlations and fluctuations we construct ratios of\nnet-baryon number cumulants as functions of temperature and chemical potential,\nwhich satisfy the experimental conditions of strangeness neutrality and\nproton/baryon ratio. Our results qualitatively explain the behavior of the\nmeasured cumulant ratios by the STAR collaboration."
    },
    {
        "anchor": "String Effects in the Wilson Loop: a high precision numerical test: We test numerically the effective string description of the infrared limit of\nlattice gauge theories in the confining regime. We consider the 3d Z(2) lattice\ngauge theory, and we define ratios of Wilson loops such that the predictions of\nthe effective string theory do not contain any adjustable parameters. In this\nway we are able to obtain a degree of accuracy high enough to show\nunambiguously that the flux--tube fluctuations are described, in the infrared\nlimit, by an effective bosonic string theory.",
        "positive": "The Running Coupling From Lattice QCD: A recent lattice calculation of the QCD running coupling is presented. The\ncoupling is extracted from the force between two static quarks in the framework\nof the valence quark approximation. A value of the Lambda-parameter for zero\nquark flavours is determined: Lambda_msbar=0.630(38)\\sqrt{\\sigma}\n=293(18)^{+25}_{-63} MeV. The first error is statistical, the second stems from\nthe overall scale uncertainty in the string tension sigma. Combining this value\nwith results from full QCD lattice simulations, we end up with the estimate\n$\\Lambda^{(4)}_{\\overline{MS}}=129(8)^{+43}_{-60}$~MeV or\n$\\alpha_{\\overline{MS}}(m_Z)=0.102^{+06}_{-11}$."
    },
    {
        "anchor": "Pseudo-Critical Temperature and Thermal Equation of State from $N_f=2$\n  Twisted Mass Lattice QCD: We report about the current status of our ongoing study of the chiral limit\nof two-flavor QCD at finite temperature with twisted mass quarks. We estimate\nthe pseudo-critical temperature $T_c$ for three values of the pion mass in the\nrange of $m_\\mathrm{PS} \\simeq 300$ and $500 \\mathrm{MeV}$ and discuss\ndifferent chiral scenarios.\n  Furthermore, we present first preliminary results for the trace anomaly,\npressure and energy density. We have studied several discretizations of\nEuclidean time up to $N_\\tau=12$ in order to assess the continuum limit of the\ntrace anomaly. From its interpolation we evaluate the pressure and energy\ndensity employing the integral method. Here, we have focussed on two pion\nmasses with $m_\\mathrm{PS} \\simeq 400$ and $700 \\mathrm{MeV}$.",
        "positive": "Finite-Volume QED Corrections to Decay Amplitudes in Lattice QCD: We demonstrate that the leading and next-to-leading finite-volume effects in\nthe evaluation of leptonic decay widths of pseudoscalar mesons at $O(\\alpha)$\nare universal, i.e. they are independent of the structure of the meson. This is\nanalogous to a similar result for the spectrum but with some fundamental\ndifferences, most notably the presence of infrared divergences in decay\namplitudes. The leading non-universal, structure-dependent terms are of\n$O(1/L^2)$ (compared to the $O(1/L^3)$ leading non-universal corrections in the\nspectrum). We calculate the universal finite-volume effects, which requires an\nextension of previously developed techniques to include a dependence on an\nexternal three-momentum (in our case, the momentum of the final state lepton).\nThe result can be included in the strategy proposed in\nRef.\\,\\cite{Carrasco:2015xwa} for using lattice simulations to compute the\ndecay widths at $O(\\alpha)$, with the remaining finite-volume effects starting\nat order $O(1/L^2)$. The methods developed in this paper can be generalised to\nother decay processes, most notably to semileptonic decays, and hence open the\npossibility of a new era in precision flavour physics."
    },
    {
        "anchor": "Lattice calculation of the strangeness and electromagnetic nucleon form\n  factors: We report on recent lattice QCD calculations of the strangeness magnetic\nmoment of the nucleon and the nucleon electromagnetic form factors, when we\nallow the electromagnetic current to connect to quark loops as well as to the\nvalence quarks. Our result for the strangeness magnetic moment is\nG_M^s(0)=-0.36+/-0.20. The sea contributions from the u and d quarks are about\n80% larger. However, they cancel to a large extent due to their electric\ncharges, resulting in a smaller net sea contribution of -0.097+/-0.037 mu_N to\nthe nucleon magnetic moment. As far as the neutron to proton magnetic moment\nratio is concerned, this sea contribution tends to cancel out the cloud-quark\neffect from the Z-graphs and results in a ratio of -0.68+/-0.04 which is close\nto the SU(6) relation and the experiment. The strangeness Sachs electric\nmean-square radius <r_s^2>_E is found to be small and negative and the total\nsea contributes substantially to the neutron electric form factor.",
        "positive": "On the Transition from Crystalline to Dynamically Triangulated Surfaces: We consider methods of interpolating between the crystalline and dynamically\ntriangulated random surface models. We argue that actions based on the\ndeviation from six of the coordination number at a site are inadequate and\npropose an alternative based on Alexander moves. Two simplified models, one of\nwhich has a phase transition and the other of which does not, are discussed."
    },
    {
        "anchor": "The high-temperature expansions of the higher susceptibilities for the\n  Ising model in general dimension d: The high-temperature expansion coefficients of the ordinary and the higher\nsusceptibilities of the spin-1/2 nearest-neighbor Ising model are calculated\nexactly up to the 20th order for a general d-dimensional (hyper)-simple-cubical\nlattice. These series are analyzed to study the dependence of critical\nparameters on the lattice dimensionality. Using the general $d$ expression of\nthe ordinary susceptibility, we have more than doubled the length of the\nexisting series expansion of the critical temperature in powers of 1/d.",
        "positive": "Finite-size scaling for two-flavor QCD and comparison with O(N) models: The chiral transition for two-flavor QCD is predicted to be in the same\nuniversality class as the 3d O(4) model. This prediction is verified in the\nWilson case, but not for the staggered-fermion case. The comparison is usually\ndone assuming infinite-volume behavior. Here we make an analysis of existing\nstaggered-fermion data using finite-size scaling and normalizing the QCD data.\nWe find better agreement for larger quark masses."
    },
    {
        "anchor": "Perturbative renormalization of moments of quark momentum, helicity and\n  transversity distributions with overlap and Wilson fermions: Using overlap as well as Wilson fermions, we have computed the one-loop\nrenormalization factors of ten non-singlet operators which measure the third\nmoment of quark momentum and helicity distributions (the lowest two having been\ncomputed in a previous paper), as well as the lowest three moments of the $g_2$\nstructure function and the lowest two non-trivial moments of the $h_1$\ntransversity structure function (plus the tensor charge). These factors are\nneeded to extract physical observables from Monte Carlo simulations of the\ncorresponding matrix elements.\n  An exact chiral symmetry is maintained in our calculations with overlap\nfermions, and its most important consequence here is that the operators\nmeasuring $g_2$ do not show any of the power-divergent mixings with operators\nof lower dimension which are present in the Wilson case. Many of our results\nfor Wilson fermions are also new; for the remaining ones, we agree with the\nliterature except in one case. The computations have been carried out using the\nsymbolic language FORM, in a general covariant gauge, which turns out also to\nbe useful in checking the gauge-invariance of the final results.",
        "positive": "Non-Gaussianities in the topological charge distribution of the SU(3)\n  Yang--Mills theory: We study the topological charge distribution of the SU(3) Yang--Mills theory\nwith high precision in order to be able to detect deviations from Gaussianity.\nThe computation is carried out on the lattice with high statistics Monte Carlo\nsimulations by implementing a naive discretization of the topological charge\nevolved with the Yang--Mills gradient flow. This definition is far less\ndemanding than the one suggested from Neuberger's fermions and, as shown in\nthis paper, in the continuum limit its cumulants coincide with those of the\nuniversal definition appearing in the chiral Ward identities. Thanks to the\nrange of lattice volumes and spacings considered, we can extrapolate the\nresults for the second and fourth cumulant of the topological charge\ndistribution to the continuum limit with confidence by keeping finite volume\neffects negligible with respect to the statistical errors. Our best results for\nthe topological susceptibility is t_0^2*chi=6.67(7)*10^-4, where t_0 is a\nstandard reference scale, while for the ratio of the forth cumulant over the\nsecond we obtain R=0.233(45). The latter is compatible with the expectations\nfrom the large Nc expansion, while it rules out the theta-behavior of the\nvacuum energy predicted by the dilute instanton model. Its large distance from\n1 implies that, in the ensemble of gauge configurations that dominate the path\nintegral, the fluctuations of the topological charge are of quantum\nnon-perturbative nature."
    },
    {
        "anchor": "The CKM matrix and CP violation (in the continuum approximation): The first part of this talk reviews recent developments in flavor physics\nthat can be made without detailed understanding of hadronic physics, driven by\nthe data. The error of sin(2beta) has shrunk below 5%, and the measurements of\nalpha and gamma have reached interesting precisions. For the first time, there\nare significant constraints on the deviations from the standard model in B-Bbar\nmixing and in b->s and b->d transitions. In the second part, I review some\ntheoretical developments for exclusive semileptonic and nonleptonic B decays\nthat have become possible using the soft-collinear effective theory. I\nconcentrate on topics where the recent progress has model independent\nimplications for interpreting the data.",
        "positive": "A stochastic approach to the reconstruction of spectral functions in\n  lattice QCD: We present a Stochastic Optimization Method (SOM) for the reconstruction of\nthe spectral functions (SPFs) from Euclidean correlation functions. In this\napproach the SPF is parameterized as a sum of randomly distributed boxes. By\nvarying the width, location and height of the boxes stochastically an optimal\nSPF can be obtained. Using this approach we reproduce mock SPFs fairly well,\nwhich contain sharp resonance peaks, transport peaks and continuum spectra. We\nalso analyzed the charmonium correlators obtained from $N_{\\tau}$=96, 48, 32\nlattices using SOM and found similar conclusion on the dissociation\ntemperatures of charmonium ground states as that obtained using the Maximum\nEntropy Method."
    },
    {
        "anchor": "Higher order finite volume quantization conditions for two spinless\n  particles: Lattice QCD calculations of scattering phaseshifts and resonance parameters\nin the two-body sector are becoming precision studies. Early calculations\nemployed L\\\"uscher's formula for extracting these quantities at lowest order.\nAs the calculations become more ambitious, higher-order relations are required.\nIn this study we present a way to validate the higher-order quantization\nconditions. This is an important step given the involved derivations of these\nformulae. We derive and validate quantization conditions up to $\\ell=5$ partial\nwaves in both cubic and elongated geometries, and for states zero and non-zero\ntotal momentum. For all 45 quantization conditions we considered (22 in cubic\nbox, 23 in elongated box) we find perfect agreement.",
        "positive": "Hadrons with a heavy colour-adjoint particle: We discuss the spectrum of hadrons with a heavy colour-adjoint particle -\nmotivated by the gluino of supersymmetry. Using the lattice approach, we\nexplore in detail the gluonic bound states - the `glueballino' or `gluelump'.\nWe also make a first determination of the spectrum of the `adjoint mesons' -\nwhich have a light quark and antiquark bound to the heavy adjoint particle. A\ncomparison of the spectra of these two systems is also made."
    },
    {
        "anchor": "Study of the scalar charmed-strange meson Ds0*(2317) with chiral\n  fermions: The recently discovered charmed-strangemeson Ds0*(2317) has been speculated\nto be a tetraquark mesonium. We study this suggestion with overlap fermions on\n2+1 flavor domain wall fermion configurations. We use 4-quark interpolating\noperatorswith Z4 grid sources on two lattices (16\\times16\\times16\\times32 and\n24\\times24\\times24 times64) to study the volume dependence of the states in an\nattempt to discern the nature of the states in the four-quark correlator to see\nif they are all two-meson scattering states or if one is a tetraquark mesonium.\nWe also use the hybrid boundary condition method for this purpose which is\ndesigned to lift the two-meson states in energy while leaving the tetraquark\nmesonium unchanged. We find that the volume method is not effective in the\npresent case due to the fact that the scattering states spectrum is closely\npacked for such heavy states so that one cannot separate out individual\nscattering states since the volume dependence is skewed as a result. However,\nthe hybrid boundary condition method works and we found that the four-quark\ncorrelators can be fitted with a tower of two-meson scattering states. We\nconclude that we do not see a tetraquark mesonium in the Ds0*(2317) meson\nregion.",
        "positive": "Statistical properties at the spectrum edge of the QCD Dirac operator: The statistical properties of the spectrum of the staggered Dirac operator in\nan SU(2) lattice gauge theory are analyzed both in the bulk of the spectrum and\nat the spectrum edge. Two commonly used statistics, the number variance and the\nspectral rigidity, are investigated. While the spectral fluctuations at the\nedge are suppressed to the same extent as in the bulk, the spectra are more\nrigid at the edge. To study this effect, we introduce a microscopic unfolding\nprocedure to separate the variation of the microscopic spectral density from\nthe fluctuations. For the unfolded data, the number variance shows oscillations\nof the same kind as before unfolding, and the average spectral rigidity becomes\nlarger than the one in the bulk. In addition, the short-range statistics at the\norigin is studied. The lattice data are compared to predictions of chiral\nrandom-matrix theory, and agreement with the chiral Gaussian Symplectic\nEnsemble is found."
    },
    {
        "anchor": "Lattice formulation of ${\\cal N}=4$ super Yang-Mills theory: We construct a lattice action for ${\\cal N}=4$ super Yang-Mills theory in\nfour dimensions which is local, gauge invariant, free of spectrum doubling and\npossesses a single exact supersymmetry. Our construction starts from the\nobservation that the fermions of the continuum theory can be mapped into the\ncomponent fields of a single real anticommuting Kahler-Dirac field. The\noriginal supersymmetry algebra then implies the existence of a nilpotent scalar\nsupercharge $Q$ and a corresponding set of bosonic superpartners. Using this\nfield content we write down a $Q$-exact action and show that, with an\nappropriate change of variables, it reduces to a well-known twist of ${\\cal\nN}=4$ super Yang-Mills theory due to Marcus. Using the discretization\nprescription developed in an earlier paper on the ${\\cal N}=2$ theory in two\ndimensions we are able to translate this geometrical action to the lattice.",
        "positive": "Kaons on the lattice: I review recent lattice results in kaon physics, particularly in the\ndetermination of V_{us} and the B_K parameter of K^0-\\bar{K}^0 mixing. I use\nlattice data to argue for the need of developing SU(2)_L \\times SU(2)_R chiral\nperturbation theory for kaon physics and discuss some recent progress in\nachieving this. In particular it is shown that for K_{\\ell 3} decays at q^2=0\n(where q is the momentum transfer between the kaon and the pion), the chiral\nlogarithms can be calculated in spite of the fact that the external pion\ncarries half the energy of the kaon (in the kaon's rest frame), because these\nlogarithms arise from soft internal loops. Future prospects, including\napplications to K\\to\\pi\\pi decays are discussed. The need to define and exploit\nrenormalization schemes which can simultaneously be implemented numerically in\nlattice simulations and used in higher-order perturbative calculations is\nexplained."
    },
    {
        "anchor": "A Determination of Interface Free Energies: We determine the interface free energy $F_{o.d.}$ between disordered and\nordered phases in the q=10 and q=20 2-d Potts models using the results of\nmulticanonical Monte Carlo simulations on $L^2$ lattices, and suitable finite\nvolume estimators. Our results, when extrapolated to the infinite volume limit,\nagree to high precision with recent analytical calculations. At the transition\npoint $\\beta_t$ the probability distribution function of the energy exhibits\ntwo maxima. Their locations have $1/L^2$ corrections, in contradiction with\nclaims of $1/L$ behavior made in the literature. Our data show a flat region\ninbetween the two maxima which characterizes two domain configurations.",
        "positive": "Nuclear force with LapH smearing: The nuclear forces are determined by combining the HAL QCD method and a new\ntype of source smearing technique. The new smearing is a projection to a space\nspanned by the lowest-lying eigenvectors of the free Laplacian operator on a\nlattice, which enables efficient calculation of hadron correlators at an\naffordable cost by utilizing the hadron-level momentum conservations. We find\nthat this new approach reduces the statistical and systematic errors in the\nresultant nuclear forces."
    },
    {
        "anchor": "A Quarkyonic Phase in Dense Two Color Matter?: We present results from simulations of Two Color QCD with two Wilson quark\nflavors in the presence of a quark chemical potential mu at two different\nlattice spacings. The equation of state, conformal anomaly, superfluid order\nparameter and Polyakov line are all discussed. Our results suggest that the\ntransition from hadronic to quark matter, and that from confined to deconfined\nmatter occur at distinct values of mu, consistent with the existence of a\nquarkyonic phase in this model.",
        "positive": "Search for the Theta^+(1540) in lattice QCD: We report on a study of the pentaquark Theta^+(1540), using a variety of\ndifferent interpolating fields. We use Chirally Improved fermions in\ncombination with Jacobi smeared quark sources to improve the signal and get\nreliable results even for small quark masses. The results of our quenched\ncalculations, which have been done on a 12^3 x 24 lattice with a lattice\nspacing of a = 0.148 fm, do not provide any evidence for the existence of a\n\\Theta^+ with positive parity. We do observe, however, a signal compatible with\nnucleon-kaon scattering state. For the negative parity the results are\ninconclusive, due to the potential mixture with nucleon-kaon and N^*-kaon\nscattering states."
    },
    {
        "anchor": "Tensor network approach to 2D Yang-Mills theories: We propose a novel tensor network representation for two-dimensional\nYang-Mills theories with arbitrary compact gauge groups. In this method, tensor\nindices are directly given by group elements with no direct use of the\ncharacter expansion. We apply the tensor renormalization group method to this\ntensor network for $SU(2)$ and $SU(3)$, and find that the free energy density\nand the energy density are accurately evaluated. We also show that the singular\nvalue decomposition of a tensor has a group theoretic structure and can be\nassociated with the character expansion.",
        "positive": "Towards the topological susceptibility with overlap fermions: Using a reweighting technique combined with a low-mode truncation of the\nfermionic determinant, we estimate the quark-mass dependence of the QCD\ntopological susceptibility with overlap fermions. In contrast to previous\nlattice simulations which all used non-chiral fermions, our results appear to\nbe consistent with the simple continuum model of D\\\"urr. This indicates that at\ncurrent lattice spacings the use of the index theorem might not be justified\nand the fermionic definition of the charge might be needed."
    },
    {
        "anchor": "Excited meson spectroscopy with two chirally improved quarks: The excited isovector meson spectrum is explored using two chirally improved\ndynamical quarks. Seven ensembles, with pion masses down to \\approx 250 MeV are\ndiscussed and used for extrapolations to the physical point. Strange mesons are\ninvestigated using partially quenched s-quarks. Using the variational method,\nwe extract excited states in several channels and most of the results are in\ngood agreement with experiment.",
        "positive": "The investigations of the $P$-wave $B_s$ states combining quark model\n  and lattice QCD in the coupled channel framework: Combining the quark model, the quark-pair-creation mechanism and $B^{(*)}\\bar\nK$ interaction, we have investigated the near-threshold $P$-wave $B_s$ states\nin the framework of the Hamiltonian effective field theory. With the heavy\nquark flavor symmetry, all the parameters are determined in the $D_s$ sector by\nfitting the lattice data. The masses of the bottom-strange partners of the\n$D^{*}_{s0}(2317)$ and $D^{*}_{s1}(2460)$ are predicted to be\n$M_{B^{*}_{s0}}=5730.2_{-1.5}^{+2.4}$ MeV and $M_{B^{*}_{s1}}=\n5769.6_{-1.6}^{+2.4}$ MeV, respectively, which are well consistent with the\nlattice QCD simulation. The two $P$-wave $B_s$ states are the mixtures of the\nbare $\\bar b s$ core and $B^{(*)}\\bar K$ component. Moreover, we find a\ncrossing point between the energy levels with and without the interaction\nHamiltonian in the finite volume spectrum in the $0^+$ case, which corresponds\nto a CDD (Castillejo-Dalitz-Dyson) zero in the $T$-matrix of the $B\\bar K$\nscattering. This CDD zero will help deepen the insights of the near-threshold\nstates and can be examined by future lattice calculation."
    },
    {
        "anchor": "Recent progress on chiral symmetry breaking in QCD: I review recent progress achieved on the lattice in the quantitative\ncomprehension of chiral symmetry breaking in QCD. Emphasis is given to the\nrecent precise computations of the spectral density of the Dirac operator in\nthe continuum limit, and of the topological susceptibility.",
        "positive": "The String Tension in Gauge Theories: a Suggestion for a New Measurement\n  Method: We discuss a new method for testing confinement and measuring the string\ntension (in the Coulomb gauge). Our numerical simulations demonstrate that the\nproblems related to Gribov copies are not harmful and that the method is\neffective in the case of pure gauge Q.C.D.. We discuss the relevance of the\nmethod for studying gauge theories coupled to fermionic matter."
    },
    {
        "anchor": "Gell-Mann-Oakes-Renner relation for multiple chiral symmetries: As a first step towards considering a chiral perturbation theory for overlap\nfermions, we investigate whether there are any ambiguities in the expression\nfor the pion mass resulting from multiple chiral symmetries. The concern is\nthat, calculating the conserved current for Ginsparg Wilson chiral symmetries\nin the usual way, different expressions of the chiral symmetries lead to\ndifferent currents. This implies an ambiguity in the definition of the pion and\npion decay constant for all Ginsparg-Wilson expressions of the Dirac operator,\nincluding the overlap operator. We use a renormalisation group mapping\nprocedure to consider local chiral symmetry transformations for a continuum\nGinsparg-Wilson \"Dirac-operator.\" We find that this naturally leads to an\nexpression for the conserved current that differs from the standard expression\nby cut-off artefacts, but is independent of which of the Ginsparg-Wilson\nsymmetries is chosen. We recover the standard expressions for the massive Dirac\noperator, propagator, and chiral condensate. With this in place, we proceed to\ncalculate the pion mass in the mapped theory as a function of the quark mass,\nand discover a unique expression for $F_\\pi$ and $m_\\pi$, recovering the usual\nGell-Mann-Oakes-Renner relation, baring the substitution of the chiral\ncondensate with its modified value. We hypothesise that the argument can be\ncarried directly over to the lattice theory.",
        "positive": "Clover improvement, spectrum and Atiyah-Singer index theorem for the\n  Dirac operator on the lattice: We study the role of the O(a)-improving clover term for the spectrum of the\nlattice Dirac operator using cooled and thermalized SU(2) gauge field\nconfigurations. For cooled configurations we observe improvement of the\nspectral properties when adding the clover term. For the thermalized case\n(12^4, beta = 2.4) without clover term we find a rather bad separation of\nphysical and doubler branches making a probabilistic interpretation of the\nAtiyah-Singer index theorem on the lattice questionable for this beta and\nlattice size. Adding the clover term leads to the creation of additional real\neigenvalues which come in pairs of opposite chirality thus further worsening\nthe situation for the index theorem."
    },
    {
        "anchor": "Free caloron gas in high temperature quenched QCD: Across the finite temperature transition to the quark-gluon plasma, the QCD\ntopological susceptibility decreases sharply. Thus in the high temperature\nphase the remaining topological objects (possibly calorons) form a weakly\ninteracting dilute gas. The overlap Dirac operator, through its exact zero\nmodes, allows one to measure the net topological charge. We show that\nseparately the number of positively and negatively charged topological objects\ncan also be extracted from the low end of the overlap Dirac spectrum. We find\nthat slightly above the phase transition their number distributions are already\nconsistent with an ideal gas of non-interacting topological objects.",
        "positive": "Dirac-mode expansion of quark number density and its implications of the\n  confinement-deconfinement transition: We investigate the quark number density at finite imaginary chemical\npotential by using the Dirac-mode expansion. In the large quark mass region, it\nis found that the quark number density can be expressed by the Polyakov loop\nand its conjugate in all order of the large quark mass expansion. Then, there\nare no specific Dirac-modes which dominantly contribute to the quark number\ndensity. In comparison, the small quark mass region is explored by using the\nquenched lattice QCD simulation. We found that the absolute value of the quark\nnumber density strongly depends on the low-lying Dirac-modes, but its sign does\nnot. This means that the existence of the Roberge-Weiss transition which is\ncharacterized by the singular behavior of the quark number density is not\nsensitive to low-lying Dirac-modes. This property enables us to discuss the\nconfinement-deconfinement transition from the behavior of the quark number\ndensity via the quark number holonomy."
    },
    {
        "anchor": "Deconfinement in SU(2) Yang-Mills theory as a center vortex percolation\n  transition: By fixing lattice Yang-Mills configurations to the maximal center gauge and\nsubsequently applying the technique of center projection, one can identify\ncenter vortices in these configurations. Recently, center vortices have been\nshown to determine the string tension between static quarks at finite\ntemperatures (center dominance); also, they correctly reproduce the deconfining\ntransition to a phase with vanishing string tension. After verifying center\ndominance also for the so-called spatial string tension, the present analysis\nfocuses on the global topology of vortex networks. General arguments are given\nsupporting the notion that the deconfinement transition in the center vortex\npicture takes the guise of a percolation transition. This transition is\ndetected in Monte Carlo experiments by concentrating on various slices through\nthe closed vortex surfaces; these slices, representing loops in lattice\nuniverses reduced by one dimension, clearly exhibit the expected transition\nfrom a percolating to a non-percolating, deconfined, phase. The latter phase\ncontains a large proportion of vortex loops winding around the lattice in the\nEuclidean time direction. At the same time, an intuitive picture clarifying the\npersistence of the spatial string tension in the deconfined phase emerges.",
        "positive": "A novel probe of the vacuum of the lattice gluodynamics: We introduce a notion of minimal number of negative links on the lattice for\na given original configuration of SU(2) fields. Negative links correspond to a\nlarge potential, not necessarily large action. The idea is that the minimal\nnumber of negative links is a gauge invariant notion. To check this hypothesis\nwe measure correlator of two negative links, averaged over all the directions,\nas function of the distance between the links. The inverse correlation length\ncoincides within the error bars with the lightest glueball mass."
    },
    {
        "anchor": "Singularities of QCD in the complex chemical potential plane: We study the thermodynamic singularities of QCD in the complex chemical\npotential plane by a numerical simulation of lattice QCD, and discuss a method\nto understand the nature of the QCD phase transition at finite density from the\ninformation of the singularities. The existence of singular points at which the\npartition function (Z) vanishes is expected in the complex plane. These are\ncalled Lee-Yang zeros or Fisher zeros. We investigate the distribution of these\nsingular points using the data obtained by a simulation of two-flavor QCD with\np4-improved staggered quarks. The convergence radius of a Taylor expansion of\nln Z in terms of the chemical potential is also discussed.",
        "positive": "Quarkonium at non-zero isospin density: We calculate the energies of quarkonium bound states in the presence of a\nmedium of nonzero isospin density using lattice QCD. The medium, created using\na canonical (fixed isospin charge) approach, induces a reduction of the\nquarkonium energies. As the isospin density increases, the energy shifts first\nincrease and then saturate. The saturation occurs at an isospin density close\nto that where previously a qualitative change in the behaviour of the energy\ndensity of the medium has been observed, which was conjectured to correspond to\na transition from a pion gas to a Bose-Einstein condensed phase. The reduction\nof the quarkonium energies becomes more pronounced as the heavy-quark mass is\ndecreased, similar to the behaviour seen in two-colour QCD at non-zero quark\nchemical potential. In the process of our analysis, the $\\eta_b$-$\\pi$ and\n$\\Upsilon$-$\\pi$ scattering phase shifts are determined at low momentum. An\ninterpolation of the scattering lengths to the physical pion mass gives\n$a_{\\eta_b,\\pi} = 0.0025(8)(6)$ fm and $a_{\\Upsilon,\\pi} = 0.0030(9)(7)$ fm."
    },
    {
        "anchor": "Gauge field smearing and controlled continuum extrapolations: Two popular methods to reduce discretisation effects are Symanzik improvement\nand gauge field smearing in the Dirac operator. Tree-level $O(a^2)$-improved\nWilson fermions can be obtained from $O(a)$-improved Wilson fermions by adding\none dimension-6 operator to the action. For gauge field smearing one wants to\navoid the situation when too much smearing leads to uncontrolled continuum\nextrapolations as the short distance behaviour is mutilated. We focus on the\ngradient flow formalism as it allows to study both smearing and physical flow.\nWe investigate the effect of smearing on the scaling towards the continuum\nlimit in pure gauge theory on the example of Creutz ratios, which provide a\nmeasure of the physical forces felt by the fermions. For suitable smearing\nstrengths we also investigate the change when the Wilson gradient flow is\nreplaced by stout smearing.",
        "positive": "Flow-based sampling for lattice field theories: Critical slowing down and topological freezing severely hinder Monte Carlo\nsampling of lattice field theories as the continuum limit is approached.\nRecently, significant progress has been made in applying a class of generative\nmachine learning models, known as \"flow-based\" samplers, to combat these\nissues. These generative samplers also enable promising practical improvements\nin Monte Carlo sampling, such as fully parallelized configuration generation.\nThese proceedings review the progress towards this goal and future prospects of\nthe method."
    },
    {
        "anchor": "Asymptotic scaling corrections in QCD with Wilson fermions from the\n  3-loop average plaquette: We calculate the 3-loop perturbative expansion of the average plaquette in\nlattice QCD with N_f massive Wilson fermions and gauge group SU(N). The\ncorrections to asymptotic scaling in the corresponding energy scheme are also\nevaluated. We have also improved the accuracy of the already known pure gluonic\nresults at 2 and 3 loops.",
        "positive": "Extraction of HQE parameters from unquenched lattice data on\n  pseudoscalar and vector heavy-light meson masses: We present a precise lattice computation of pseudoscalar and vector\nheavy-light meson masses for heavy-quark masses ranging from the physical charm\nmass up to $\\simeq 4$ times the physical b-quark mass. We employ the gauge\nconfigurations generated by the European Twisted Mass Collaboration (ETMC) with\n$N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a\n\\simeq 0.062, 0.082, 0.089$ fm) with pion masses in the range $M_\\pi \\simeq 210\n- 450$ MeV. The heavy-quark mass is simulated directly on the lattice up to\n$\\simeq 3$ times the physical charm mass. The interpolation to the physical\n$b$-quark mass is performed using the ETMC ratio method, based on ratios of the\nmeson masses computed at nearby heavy-quark masses, and adopting the kinetic\nmass scheme. The extrapolation to the physical pion mass and to the continuum\nlimit yields $m_b^{\\rm kin}(1~\\mbox{GeV}) = 4.61 (20)$ GeV, which corresponds\nto $\\overline{m}_b(\\overline{m}_b) = 4.26 (18)$ GeV in the $\\overline{MS}$\nscheme. The lattice data are analyzed in terms of the Heavy Quark Expansion\n(HQE) and the matrix elements of dimension-4 and dimension-5 operators are\nextracted with a good precision, namely: $\\overline{\\Lambda} = 0.552 (26)$ GeV,\n$\\mu_\\pi^2 = 0.321 (32)$ GeV$^2$ and $\\mu_G^2(m_b) = 0.253 (25)$ GeV$^2$. The\ndata also allow for a rough estimate of the dimension-6 operator matrix\nelements. As the HQE parameters play a crucial role in the inclusive\ndetermination of the Cabibbo-Kobayashi-Maskawa matrix elements $V_{ub}$ and\n$V_{cb}$, their precise determination on the lattice may eventually validate\nand improve the analyses based on fits to the semileptonic moments."
    },
    {
        "anchor": "Some remarks on the Ginsparg-Wilson fermion: We note that Fujikawa's proposal of generalization of the Ginsparg-Wilson\nrelation is equivalent to setting $R = (a \\gamma_5 D)^{2k}$ in the original\nGinsparg-Wilson relation $D \\gamma_5 + \\gamma_5 D = 2 a D R \\gamma_5 D$. An\nexplicit realization of D follows from the Overlap construction. The general\nproperties of D are derived. The chiral properties of these higher-order (k >\n0) realizations of Overlap Dirac operator are compared to those of the\nNeuberger-Dirac operator (k = 0), in terms of the fermion propagator, the axial\nanomaly and the fermion determinant in a background gauge field. Our present\nresults (up to lattice size 16 x 16) indicate that the chiral properties of the\nNeuberger-Dirac operator are better than those of higher-order ones.",
        "positive": "The $N_f= 2$ chiral phase transition from imaginary chemical potential\n  with Wilson Fermions: The order of the thermal transition in the chiral limit of QCD with two\ndynamical flavours of quarks is a long-standing issue. Still, it is not\ndefinitely known whether the transition is of first or second order in the\ncontinuum limit. Which of the two scenarios is realized has important\nimplications for the QCD phase diagram and the existence of a critical endpoint\nat finite densities. Settling this issue by simulating at successively\ndecreased pion mass was not conclusive yet. Recently, an alternative approach\nwas proposed, extrapolating the first order phase transition found at imaginary\nchemical potential to zero chemical potential with known exponents, which are\ninduced by the Roberge-Weiss symmetry. For staggered fermions on $N_t=4$\nlattices, this results in a first order transition in the chiral limit. Here we\nreport of $N_t=4$ simulations with Wilson fermions, where the first order\nregion is found to be large."
    },
    {
        "anchor": "Scattering from finite-volume energies including higher partial waves\n  and multiple decay channels: A new implementation of estimating the two-to-two $K$-matrix from\nfinite-volume energies based on the Luescher formalism is described. The method\nincludes higher partial waves and multiple decay channels, and the fitting\nprocedure properly includes all covariances and statistical uncertainties. The\nmethod is also simpler than previously used procedures. Formulas and software\nfor handling total spins up to $S=2$ and orbital angular momenta up to $L=6$\nare presented.",
        "positive": "Center dominance, Casimir scaling, and confinement in lattice gauge\n  theory: We present numerical evidence that supports the theory of quark confinement\nbased on center vortex condensation. We introduce a special gauge (\"maximal\ncenter gauge\") and center projection, suitable for identification of center\nvortices. Main focus is then put on the connection of vortices in center\nprojection to \"confiners\" in full, unprojected gauge-field configurations.\nTopics briefly discussed include: the relation between vortices and monopoles,\nfirst results for SU(3), and the problem of Casimir scaling."
    },
    {
        "anchor": "Continuum Moment Equations on the Lattice: An analysis is given as to why one can not directly evaluate continuum moment\nequations, i.e., equations involving powers of the position variable times\ncharge, current, or energy/momentum operators, on the lattice. I examine two\ncases: a three point function evaluation of the nucleon magnetic moment and a\nfour point function (charge overlap) evaluation of the pseudoscalar charge\nradius.",
        "positive": "Electromagnetic splitting of quark and pseudoscalar meson masses from\n  dynamical QCD + QED: Lattice QCD simulations are now reaching a precision where electromagnetic\ncorrections from QED become important. In investigating the effects of SU(3)\nbreaking due to quark mass differences within QCD, a group-theoretical analysis\nof the mass dependence greatly helped us organize our results. We now do the\nsame with electromagnetic charge effects by extending the calculations to\ndynamical 1+1+1 flavor QCD + QED."
    },
    {
        "anchor": "Calculation of derivative of nucleon form factors in $N_f = 2+1$ lattice\n  QCD at $M_\u03c0= 138$ MeV on a (5.5 fm)$^3$ volume: We present a direct calculation for the first derivative of the isovector\nnucleon form factors with respect to the momentum transfer $q^2$ using the\nlower moments of the nucleon 3-point function in the coordinate space. Our\nnumerical simulations are performed using the $N_f = 2 + 1$ nonperturbatively\n$O(a)$-improved Wilson quark action and Iwasaki gauge action near the physical\npoint, corresponding to the pion mass $M_\\pi =138$ MeV, on a (5.5 fm)$^4$\nlattice at a single lattice spacing of $a = 0.085$ fm. In the momentum\nderivative approach, we can directly evaluate the mean square radii for the\nelectric, magnetic, and axial-vector form factors, and also the magnetic moment\nwithout the $q^2$ extrapolation to the zero momentum point. These results are\ncompared with the ones determined by the standard method, where the $q^2$\nextrapolations of the corresponding form factors are carried out by fitting\nmodels. We find that the new results from the momentum derivative method are\nobtained with a larger statistical error than the standard method, but with a\nsmaller systematic error associated with the data analysis. Within the total\nerror range of the statistical and systematic errors combined, the two results\nare in good agreement. On the other hand, two variations of the momentum\nderivative of the induced pseudoscalar form factor at the zero momentum point\nshow some discrepancy. It seems to be caused by a finite volume effect, since a\nsimilar trend is not observed on a large volume, but seen on a small volume in\nour pilot calculations at a heavier pion mass of $M_{\\pi}= 510$ MeV.\nFurthermore, we discuss an equivalence between the momentum derivative method\nand the similar approach with the point splitting vector current.",
        "positive": "Doubly charmed tetraquark $T_{cc}^+$ in (2+1)-flavor QCD near physical\n  point: We study the doubly charmed tetraquark state $T_{cc}^+$ by the HAL QCD method\napplied to the $D^*D$ system in $(2+1)$ flavor lattice QCD at nearly physical\npion mass, $m_\\pi= 146$ MeV. We obtain the attractive potential at all\ndistances in the $S$-wave of the isoscalar $D^* D$ system, whose long distance\nbehavior is well described by the two-pion exchange (TPE), and it generates a\nvirtual pole near $D^* D$ threshold with a pole position $E_{\\rm pole} = -59\n(^{+53}_{-99}) (^{+2}_{-67})$ keV and an inverse scattering length\n$1/a_0=0.05(5)(^{+2}_{-2})$ fm$^{-1}$. The virtual pole turns into a loosely\nbound state pole if the pion mass in the TPE potential is extrapolated to the\nphysical value, $m_\\pi =135$ MeV. The potential at the physical pion mass is\nshown to give a semi-quantitative description of the $D^0 D^0\\pi^+$ mass\nspectrum at the LHCb."
    },
    {
        "anchor": "Review of Baryon Spectroscopy in Lattice QCD: The complex patterns of the hadronic spectrum have puzzled physicists since\nthe early discovery of the \"particle zoo\" in the 1960s. Today, the properties\nof these myriad particles are understood to be the result of quantum\nchromodynamics (QCD) with some modification by the electroweak interactions.\nDespite the discovery of this fundamental theory, the description of the\nhadronic spectrum has long been dominated by phenomenological models, due to\nthe difficulties of addressing QCD in the strong-coupling regime, where\nnonperturbative effects are essential. By making numerical calculations in\ndiscretized spacetime, lattice gauge theory enables the ab initio study of many\nlow-energy properties of QCD. Significant efforts are underway internationally\nto use lattice QCD to directly compute properties of ground and excited-state\nbaryons. Detailed knowledge of the hadronic spectrum will provide insight into\nthe character of these states beyond what can be extracted from models.\n  In this review, I will focus on the latest progress in lattice calculations\nof the $P_{11}(1440)$, the poorly known hyperon spectrum and the energies of\nhighly-excited states of the nucleon, Delta and other light-flavor baryons. In\nthe heavy-flavor sector, I will concentrate on recent lattice-QCD calculations\nof baryon masses, particularly those that make predictions concerning\nyet-to-be-discovered baryons, such as $\\Omega_{cc}$, $\\Xi^\\prime_b$ or\ntriply-heavy baryons.",
        "positive": "Frustration in Finite Density QCD: We present a detailed analysis of the QCD partition function in the Grand\nCanonical formalism. Using the fugacity expansion we find evidence for\nnumerical instabilities in the standard evaluation of its coefficients. We\ndiscuss the origin of this problem and propose an issue to it. The correct\nanalysis shows no evidence for a discontinuity in the baryonic density in the\nstrong coupling limit. The moderate optimism that was inspired by the Grand\nCanonical Partition Function calculations in the last years has to be\nconsidered ill-founded."
    },
    {
        "anchor": "Weyl Neutrinos on a Lattice: An Explicit Construction: Introducing a new and universally applicable discretizing technique, I\nconstruct a class of local and unitary lattice theories of Weyl neutrinos; this\nsolves a longstanding and allegedly unsolvable problem in quantum field theory.\nEn route, I also prove a general ``go'' theorem that all Lagrangian-density\nbased continuum quantum field theories can be lattice-regularized.\n  (INFORMAL ABSTRACT: You didn't study the Nielsen-Ninomiya theorem, only\ntrusted the authors to have proven ``the absence of neutrinos on a lattice''.\nWell, they didn't. Nor can anyone else: every continuum theory can be\nlattice-regularized. A proof of that, plus an explicit construction of lattice\nneutrinos: if you read only one paper this year, here it is! From now on, this\nis how chiral fermions should be latticized. All else is gaslight.)",
        "positive": "Canonical fermion determinants in lattice QCD - Numerical evaluation and\n  properties: We analyze canonical fermion determinants, i.e., fermion determinants\nprojected to a fixed quark number q. The canonical determinants are computed\nusing a dimensional reduction formula and are studied for pure SU(3) gauge\nconfigurations in a wide range of temperatures. It is demonstrated that the\ncenter sectors of the Polyakov loop very strongly manifest themselves in the\nbehavior of the canonical determinants in the deconfined phase, and we discuss\nphysical implications of this finding. Furthermore the distribution of the\nquark sectors is studied as a function of the temperature."
    },
    {
        "anchor": "Exploring the epsilon regime with lattice Wilson fermions: We study the impact of explicit chiral symmetry breaking of lattice Wilson\nfermions on mesonic correlators in the epsilon-regime using Wilson chiral\nperturbation theory. We generalize the epsilon-expansion of continuum chiral\nperturbation theory to nonzero lattice spacing a and distinguish various\nregimes. It turnes out that lattice corrections are highly suppressed, as long\nas quark masses are of the order a\\Lambda^2_QCD. The lattice spacing effects\nbecome more pronounced for smaller quark masses and may lead to non-trivial\ncorrections of the continuum results at next-to-leading order. We compute these\ncorrections for standard current and density correlation functions. A fit to\nlattice data shows that these corrections are small, as expected.",
        "positive": "Encoding field theories into gravities: We propose a method to give a $d+1$ geometry from a $d$ dimensional quantum\nfield theory in the large N expansion. We first construct a $d+1$ dimensional\nfield from the $d$ dimensional one using the gradient flow equation, whose flow\ntime $t$ represents the energy scale of the system such that $t\\rightarrow 0$\ncorresponds to the ultra-violet (UV) while $t\\rightarrow\\infty$ to the\ninfra-red (IR). We define the induced metric using $d+1$ dimensional field\noperators. We show that the metric defined in this way becomes classical in the\nlarge N limit: quantum fluctuations of the metric are suppressed as 1/N due to\nthe large $N$ factorization property. As a concrete example, we apply our\nmethod to the O(N) non-linear $\\sigma$ model in two dimensions. We calculate\nthe three dimensional induced metric, which describes an AdS space in the\nmassless limit. We finally discuss several open issues for future\ninvestigations."
    },
    {
        "anchor": "Application of chiral perturbation theory to 2+1 flavor lattice QCD with\n  O(a)-improved Wilson quarks: We apply chiral perturbation theory to the pseudoscalar meson mass and decay\nconstant data obtained in the PACS-CS Project toward 2+1 flavor lattice QCD\nsimulations with the O(a)-improved Wilson quarks. We examine the existence of\nchiral logarithms in the quark mass range from m_{ud}=47 MeV down to 6 MeV on a\n(2.8 fm)^3 box with the lattice spacing a=0.09 fm. Several low energy constants\nare determined. We also discuss the magnitude of finite size effects based on\nchiral perturbation theory.",
        "positive": "Mass of a quantum 't Hooft-Polyakov monopole: The quantum mechanical mass of 't Hooft-Polyakov monopoles in the\nfour-dimensional Georgi-Glashow is calculated non-perturbatively using lattice\nMonte Carlo simulations. This is done by imposing twisted boundary conditions\nthat ensure there is one unit of magnetic charge on the lattice, and measuring\nthe free energy difference between this ensemble and the vacuum. In the\nweak-coupling limit, the results can be used to determine the quantum\ncorrection to the classical mass, once renormalisation of couplings is taken\nproperly into account. The methods can also be used to study the masses at\nstrong coupling, i.e., near the critical point, where there are hints of a\npossible electric-magnetic duality."
    },
    {
        "anchor": "Constraining a fourth generation of quarks: non-perturbative Higgs boson\n  mass bounds: We present a non-perturbative determination of the upper and lower Higgs\nboson mass bounds with a heavy fourth generation of quarks from numerical\nlattice computations in a chirally symmetric Higgs-Yukawa model. We find that\nthe upper bound only moderately rises with the quark mass while the lower bound\nincreases significantly, providing additional constraints on the existence of a\nstraight-forward fourth quark generation. We examine the stability of the lower\nbound under the addition of a higher dimensional operator to the scalar field\npotential using perturbation theory, demonstrating that it is not significantly\naltered for small values of the coupling of this operator. For a Higgs boson\nmass of $\\sim125\\mathrm{GeV}$ we find that the maximum value of the fourth\ngeneration quark mass is $\\sim300\\mathrm{GeV}$, which is already in conflict\nwith bounds from direct searches.",
        "positive": "New gauge-independent transition separating confinement-Higgs phase in\n  the lattice gauge-fundamental scalar model: The lattice gauge-scalar model with the scalar field in the fundamental\nrepresentation of the gauge group has a single confinement-Higgs phase which is\nwell-known as the Fradkin-Shenker-Osterwalder-Seiler analytic continuity\ntheorem: Confinement and Higgs regions are subregions of an analytically\ncontinued single phase and there are no thermodynamics phase transitions\nbetween them. In this talk, however, we show that we can define new type of\noperators which enable to separate completely the confinement phase and the\nHiggs phase. In fact, they are constructed in the gauge-invariant procedure by\ncombining the original scalar field and the so-called color-direction field\nwhich is obtained by change of field variables based on the gauge-covariant\ndecomposition of the gauge field due to Cho-Duan-Ge-Shabanov and Faddeev-Niemi.\nWe perform the numerical simulations for the model with SU(2) gauge group\nwithout any gauge fixing and find a new transition line which agrees with the\nconventional thermodynamic transition line in the weak gauge coupling and\ndivides the confinement-Higgs phase into two separate phases, confinement and\nthe Higgs, in the strong gauge coupling. All results are obtained in the\ngauge-independent way, since no gauge fixing has been imposed in the numerical\nsimulations. Moreover, we give a physical interpretation for the new transition\nfrom the viewpoint of the spontaneous breaking of a global symmetry. This talk\nis based on the preprint [1]."
    },
    {
        "anchor": "The anti-B --> D* lepton anti-neutrino form factor at zero recoil and\n  the determination of V(cb): We summarize our lattice QCD study of the form factor at zero recoil in the\ndecay anti-B --> D* lepton anti-neutrino. After careful consideration of all\nsources of systematic uncertainty, we find,\n  h_A1(1) = 0.913(+0.024-0.017)(+0.017-0.030), where the first uncertainty is\nfrom statistics and fitting while the second combined uncertainty is from all\nother systematic effects.",
        "positive": "Dual representation for massless fermions with chemical potential and\n  U(1) gauge fields: Complex action problems coming from either a chemical potential or a\ntopological term have been solved for several models in recent years by mapping\nthem to so-called dual degrees of freedom. In terms of these dual variables the\npartition sum has only real and positive contributions such that a Monte Carlo\nsimulation is possible. In this paper we discuss a dual representation for\nmassless staggered fermions in two dimensions coupled to a U(1) gauge field. We\ninclude a topological term, and for the case of several flavors with vanishing\ntotal charge also a chemical potential. We show that the real and positive\ndualization can also be generalized to a system of nanowires (1+1 dimensional\nfermions) coupled to a 3+1 dimensional U(1) gauge field."
    },
    {
        "anchor": "Dual lattice simulation of the U(1) gauge-Higgs model at finite density\n  - an exploratory proof-of-concept study: The U(1) gauge-Higgs model with two flavors of opposite charge and a chemical\npotential is mapped exactly to a dual representation where matter fields\ncorrespond to loops of flux and the gauge fields are represented by surfaces.\nThe complex action problem of the conventional formulation at finite chemical\npotential mu is overcome in the dual representation and the partition sum has\nonly real and non-zero contributions. We simulate the model in the dual\nrepresentation using a generalized worm algorithm, explore the phase diagram\nand study condensation phenomena at finite mu.",
        "positive": "The pion quasiparticle in the low-temperature phase of QCD: We investigate the properties of the pion quasiparticle in the\nlow-temperature phase of two-flavor QCD on the lattice with support from chiral\neffective theory. We find that the pion quasiparticle mass is significantly\nreduced compared to its value in the vacuum, by contrast with the static\nscreening mass, which increases with temperature. By a simple argument, near\nthe chiral limit the two masses are expected to determine the quasiparticle\ndispersion relation. Analyzing two-point functions of the axial charge density\nat non-vanishing spatial momentum, we find that the predicted dispersion\nrelation and the residue of the pion pole are simultaneously consistent with\nthe lattice data at low momentum. The test, based on fits to the correlation\nfunctions, is confirmed by a second analysis using the Backus-Gilbert method."
    },
    {
        "anchor": "Hot electroweak matter near to the endpoint of the phase transition: The electroweak phase transition is investigated near to its endpoint in the\nframework of an effective three-dimensional model. We measure the very weak\ninterface tension with the tunneling correlation length method. First results\nfor the mass spectrum and the corresponding wave functions in the symmetric\nphase are presented.",
        "positive": "Lattice Fermions and Chiral Symmetry: We propose a formulation of lattice fermions with one-sided differences that\nis hermitian, chirally symmetric (barring a bare mass term) and completely free\nof doubling. To obtain the axial anomaly in perturbation theory it was\nnecessary to break chiral symmetry on the lattice only through a bare mass term\nfor the physical fermion. The chiral limit may be taken once the continuum\nlimit is reached. We comment on the role of the mass term with examples\nelsewhere in field theory."
    },
    {
        "anchor": "One-Flavor Algorithms for Simulation of Lattice QCD with Domain-Wall\n  Fermion: EOFA versus RHMC: We compare the performances of the exact one-flavor algorithm (EOFA) and the\nrational hybrid Monte Carlo algorithm (RHMC), for dynamical simulations of\nlattice QCD with domain-wall fermion.",
        "positive": "Generalized L\u00fcscher's Formula in Multichannel Baryon-Baryon Scattering: In this paper, L\\\"uscher's formula is generalized to the case of two\nspin-$\\frac{1}{2}$ particles in two-channel scattering based on Ref.\n\\cite{Li:2012bi}. This is first done in a non-relativistic quantum mechanics\nmodel and then generalized to quantum field theory. We show that L\\\"uscher's\nformula obtained from these two different methods are equivalent up to terms\nthat are exponentially suppressed in the box size. This formalism can be\nreadily applied to future lattice QCD calculations."
    },
    {
        "anchor": "Bottomonium spectrum at order v^6 from domain-wall lattice QCD: precise\n  results for hyperfine splittings: The bottomonium spectrum is computed in dynamical 2+1 flavor lattice QCD,\nusing NRQCD for the b quarks. The main calculations in this work are based on\ngauge field ensembles generated by the RBC and UKQCD collaborations with the\nIwasaki action for the gluons and a domain-wall action for the sea quarks.\nLattice spacing values of approximately 0.08 fm and 0.11 fm are used, and\nsimultaneous chiral extrapolations to the physical pion mass are performed. As\na test for gluon discretization errors, the calculations are repeated on two\nensembles generated by the MILC collaboration with the Luscher-Weisz gauge\naction. Gluon discretization errors are also studied in a lattice potential\nmodel using perturbation theory for four different gauge actions. The\nnonperturbative lattice QCD results for the radial and orbital bottomonium\nenergy splittings obtained from the RBC/UKQCD ensembles are found to be in\nexcellent agreement with experiment. To get accurate results for spin\nsplittings, the spin-dependent order-v^6 terms are included in the NRQCD\naction, and suitable ratios are calculated such that most of the unknown\nradiative corrections cancel. The cancellation of radiative corrections is\nverified explicitly by repeating the calculations with different values of the\ncouplings in the NRQCD action. Using the lattice ratios of the S-wave hyperfine\nand the 1P tensor splitting, and the experimental result for the 1P tensor\nsplitting, the 1S hyperfine splitting is found to be\n60.3+-5.5(stat)+-5.0(syst)+-2.1(exp) MeV, and the 2S hyperfine splitting is\npredicted to be 23.5+-4.1(stat)+-2.1(syst)+-0.8(exp) MeV.",
        "positive": "Lattice Investigations of the Running Coupling: A review of investigations of running couplings using lattice techniques is\ngiven. This includes i) studies of the running of particular non-perturbatively\ndefined renormalized couplings in pure gauge theories over a range of energies,\nand ii) how estimates of $\\alpha_{\\overline{MS}}(m_Z)$ in lattice QCD are\npresently obtained."
    },
    {
        "anchor": "Lattice simulations with $N_f=2+1$ improved Wilson fermions at a fixed\n  strange quark mass: The explicit breaking of chiral symmetry of the Wilson fermion action results\nin additive quark mass renormalization. Moreover, flavour singlet and\nnon-singlet scalar currents acquire different renormalization constants with\nrespect to continuum regularization schemes. This complicates keeping the\nrenormalized strange quark mass fixed when varying the light quark mass in\nsimulations with $N_f=2+1$ sea quark flavours. Here we present and validate our\nstrategy within the CLS (Coordinated Lattice Simulations) effort to achieve\nthis in simulations with non-perturbatively order-$a$ improved Wilson fermions.\nWe also determine various combinations of renormalization constants and\nimprovement coefficients.",
        "positive": "Semileptonic $B\\to\u03c0\\ell\u03bd$, $B\\to D\\ell\u03bd$, $B_s\\to K\\ell\u03bd$, and\n  $B_s\\to D_s\\ell\u03bd$ decays: We present updates for our nonperturbative lattice QCD calculations to\ndetermine semileptonic form factors for exclusive $B\\to \\pi\\ell\\nu$, $B\\to D\n\\ell\\nu$, $B_s\\to K\\ell \\nu$, and $B_s\\to D_s\\ell\\nu$ decays. Our calculation\nis based on RBC-UKQCD's set of $2+1$-dynamical-flavor gauge field ensembles. In\nthe valence sector we use domain wall fermions for up/down, strange and charm\nquarks, whereas bottom quarks are simulated with the relativistic heavy quark\naction. The continuum limit is based on three lattice spacings. Using\nkinematical $z$ expansions we aim to obtain form factors over the full $q^2$\nrange. These form factors are the basis for predicting ratios addressing lepton\nflavor universality or, when combined with experimental results, to obtain CKM\nmatrix elements $|V_{ub}|$ and $|V_{cb}|$."
    },
    {
        "anchor": "Universality check of the overlap fermions in the Schroedinger\n  functional: I examine some properties of the overlap operator in the Schroedinger\nfunctional formulated by Luescher at perturbative level. By investigating\nspectra of the free operator and one-loop coefficient of the Schroedinger\nfunctional coupling, I confirm the universality at tree and one-loop level.\nFurthermore, I address cutoff effects of the step scaling function and it turns\nout that the lattice artifacts for the overlap operator are comparable with\nthose of the clover actions.",
        "positive": "Progress on the nature of the QCD thermal transition as a function of\n  quark flavors and masses: We investigate to which extent we can exploit the dependence of the order of\nthe chiral transition on the number of light degenerate flavors $N_\\text{f}$,\nre-interpreted as continuous parameter in the path integral formulation, as a\nmeans to perform a controlled chiral extrapolation and deduce the order of the\ntransition for the case $N_\\text{f}=2$, which is still under debate."
    },
    {
        "anchor": "Supersymmetric gauge theories on the lattice: Pfaffian phases and the\n  Neuberger 0/0 problem: Recently a class of supersymmetric gauge theories have been successfully\nimplemented on the lattice. However, there has been an ongoing debate on\nwhether lattice versions of some of these theories suffer from a sign problem,\nwith independent simulations for the ${\\cal N} = (2, 2)$ supersymmetric\nYang-Mills theories in two dimensions yielding seemingly contradictory results.\nHere, we address this issue from an interesting theoretical point of view. We\nconjecture that the sign problem observed in some of the simulations is related\nto the so called Neuberger 0/0 problem, which arises in ordinary\nnon-supersymmetric lattice gauge theories, and prevents the realization of\nBecchi-Rouet-Stora-Tyutin symmetry on the lattice. After discussing why we\nexpect a sign problem in certain classes of supersymmetric lattice gauge\ntheories far from the continuum limit, we argue that these problems can be\nevaded by use of a non-compact parametrization of the gauge link fields.",
        "positive": "Chiral phase transition in a lattice fermion--gauge--scalar model with\n  U(1) gauge symmetry: The chiral phase transition induced by a charged scalar field is investigated\nnumerically in a lattice fermion-gauge-scalar model with U(1) gauge symmetry,\nproposed recently as a model for dynamical fermion mass generation. For very\nstrong gauge coupling the transition is of second order and its scaling\nproperties are very similar to those of the Nambu--Jona-Lasinio model. However,\nin the vicinity of the tricritical point at somewhat weaker coupling, where the\ntransition changes the order, the scaling behavior is different. Therefore it\nis worthwhile to investigate the continuum limit of the model at this point."
    },
    {
        "anchor": "Performance of several Lanczos eigensolvers with HISQ fermions: We investigate the state-of-the-art Lanczos eigensolvers available in the\nGrid and QUDA libraries. They include Implicitly Restarted Lanczos,\nThick-Restart Lanczos, and Block Lanczos. We measure and analyze their\nperformance for the Highly Improved Staggered Quark (HISQ) Dirac operator. We\nalso discuss optimization of Chebyshev acceleration.",
        "positive": "Excitations of static isolated fermions in the Higgs phase of gauge\n  Higgs theory: A spectrum of localized excitations of isolated static fermions has been\ndiscovered in several different gauge Higgs theories. In lattice numerical\nsimulations, we show that the charged elementary particles can have the\nspectrum of excitations in the Higgs phase of SU(3) gauge Higgs theory, $q=2$\nAbelian Higgs theory, Landau-Ginzburg theory, and in chiral U(1) gauge Higgs\ntheory. Possibly these excited states of the isolated fermions can be observed\nin ARPES studies of conventional superconductors. Also, we consider that\nsimilar kinds of excitations could exist in other gauge Higgs theories, such as\nthe electroweak sector of the Standard Model."
    },
    {
        "anchor": "Renormalization of the Lattice Heavy Quark Classical Velocity: In the lattice formulation of the Heavy Quark Effective Theory (LHQET), the\nclassical velocity is renormalized. The origin of this renormalization is the\nreduction of Lorentz (or O(4)) invariance to (hyper)cubic invariance. The\nrenormalization is finite and depends on the form of the decretization of the\nreduced heavy quark Dirac equation. For the Forward Time - Centered Space\ndiscretization, the renormalization is computed both perturbatively, to one\nloop, and non-perturbatively using an ensemble of lattices provided by the\nFermilab lattice collaboration. The estimates of the leading (linear) shift\nagree, and indicate that for small classical velocities, the renormalized\nvelocity is reduced by about 25-30% relative to its bare (input) value.",
        "positive": "Overcoming the sign problem in 1-dimensional QCD by new integration\n  rules with polynomial exactness: In this paper we describe a new integration method for the groups $U(N)$ and\n$SU(N)$, for which we verified numerically that it is polynomially exact for\n$N\\le 3$. The method is applied to the example of 1-dimensional QCD with a\nchemical potential. We explore, in particular, regions of the parameter space\nin which the sign problem appears due the presence of the chemical potential.\nWhile Markov Chain Monte Carlo fails in this region, our new integration method\nstill provides results for the chiral condensate on arbitrary precision,\ndemonstrating clearly that it overcomes the sign problem. Furthermore, we\ndemonstrate that our new method leads to orders of magnitude reduced errors\nalso in other regions of parameter space."
    },
    {
        "anchor": "Non-perturbative Renormalization of Bilinear Operators on Fine Lattice: We present results of the wave function renormalization factor $Z_q$ and mass\nrenormalization factor $Z_m$ obtained using non-perturbative renormalization\n(NPR) method in the RI-MOM scheme with HYP improved staggered quarks. We use\nfine ensembles of MILC asqtad lattices ($N_f = 2+1$) with $28^3 \\times 96$\ngeometry, $a \\approx 0.09$\\,fm, and $am_\\ell/am_s = 0.0062/0.031 $. We also\nstudy on scalability of $Z_q$ and $Z_m$ by comparing the results on the coarse\nand fine ensembles.",
        "positive": "Status of the MILC light pseudoscalar meson project: We discuss the current status of our calculation of the physics of pi and K\nmesons using three dynamical flavors of improved staggered quarks. This year,\nwe have a new ensemble with a lattice spacing of 0.06 fm and a light sea mass\nof 0.2 m_s, as well as significant increases in statistics at several coarser\nlattice spacings and/or heavier sea masses. Results for decay constants, quark\nmasses, low energy constants, condensates, and V_{us} are presented."
    },
    {
        "anchor": "A determination of the average up-down, strange and charm quark masses\n  from $N_f=2+1+1$: We present a lattice QCD determination of the average up-down, strange and\ncharm quark masses based on simulations performed by the European Twisted Mass\nCollaboration with $N_f = 2 + 1 + 1$ dynamical fermions. We simulated at three\ndifferent values of the lattice spacing, the smallest being approximately\n$0.06fm$, and with pion masses as small as $210 \\text{MeV}$. Our results are:\n$m_{ud}(2\\text{GeV})=3.70(17)\\text{MeV}$,\n$m_s(2\\text{GeV})=99.2(3.9)\\text{MeV}$, $m_c(m_c)=1.350(49)\\text{GeV}$,\n$m_s/m_{ud}=26.64(30)$ and $m_c/m_s=11.65(12)$.",
        "positive": "Theoretical analysis of multi-boson algorithm with local and global\n  update of bosonic fields: We estimate theoretically the cost of the multi-boson method in the\nnon-hermitian approximation. It is shown that it is proportional to $V(\\log\nV)^2/m^4$. For a global update of the scalar fields the cost decreases by a\nfactor $m$ with a $\\log V$ overhead."
    },
    {
        "anchor": "Critical behavior of 3D Z(N) lattice gauge theories at zero temperature: Three-dimensional $Z(N)$ lattice gauge theories at zero temperature are\nstudied for various values of $N$. Using a modified phenomenological\nrenormalization group, we explore the critical behavior of the generalized\n$Z(N)$ model for $N=2,3,4,5,6,8$. Numerical computations are used to simulate\nvector models for $N=2,3,4,5,6,8,13,20$ for lattices with linear extension up\nto $L=96$. We locate the critical points of phase transitions and establish\ntheir scaling with $N$. The values of the critical indices indicate that the\nmodels with $N>4$ belong to the universality class of the three-dimensional\n$XY$ model. However, the exponent $\\alpha$ derived from the heat capacity is\nconsistent with the Ising universality class. We discuss a possible resolution\nof this puzzle. We also demonstrate the existence of a rotationally symmetric\nregion within the ordered phase for all $N\\geq 5$ at least in the finite\nvolume.",
        "positive": "Two-colour QCD at finite fundamental quark-number density and related\n  theories: We are simulating SU(2) Yang-Mills theory with four flavours of dynamical\nquarks in the fundamental representation of SU(2) `colour' at finite chemical\npotential, mu for quark number, as a model for QCD at finite baryon number\ndensity. In particular we observe that for mu large enough this theory\nundergoes a phase transition to a state with a diquark condensate which breaks\nquark-number symmetry. In this phase we examine the spectrum of light scalar\nand pseudoscalar bosons and see evidence for the Goldstone boson associated\nwith this spontaneous symmetry breaking. This theory is closely related to QCD\nat finite chemical potential for isospin, a theory which we are now studying\nfor SU(3) colour."
    },
    {
        "anchor": "Decay constants from twisted mass QCD: We present results for chiral extrapolations of the mass and decay constants\nof the rho meson. The data sets used are the nf=2 unquenched gauge\nconfigurations generated with twisted mass fermions by the European Twisted\nMass Collaboration. We describe a calculation of three decay constants in\ncharmonium and explain why they are required.",
        "positive": "The vector and axial currents in Wilson chiral perturbation theory: We reconsider the construction and matching of the vector and axial currents\nin Wilson Chiral Perturbation Theory (WChPT), the low-energy effective theory\nfor lattice QCD with Wilson fermions. In particular, we discuss in detail the\nimpact of the finite renormalization of the currents on their matching from the\nlattice theory to WChPT.We explicitly show that imposing chiral Ward-Takahashi\nidentities on the currents leads, in general, to additional terms of O(a) in\nthe axial current. We illustrate the impact on physical quantities by computing\nthe pion decay constant to one-loop order in the two flavor theory. Our result\ndiffers from previously published ones."
    },
    {
        "anchor": "Flux tube delocalization at the deconfinement point: We study the behaviour of the flux tube thickness in the vicinity of the\ndeconfinement transition. We show, using effective string methods, that in this\nregime the square width increases linearly and not logarithmically with the\ninterquark distance. The amplitude of this linear growth is an increasing\nfunction of the temperature and diverges as the deconfinement transition is\napproached from below. These predictions are in good agreement with a set of\nsimulations performed in the 3d gauge Ising model.",
        "positive": "Phases of a strongly coupled four-fermion theory: We present ongoing investigations of a four-dimensional lattice field theory\nwith four massless reduced staggered fermions coupled through an\nSU(4)-invariant four-fermion interaction. As in previous studies of\nfour-fermion and Higgs--Yukawa models with different lattice fermion\ndiscretizations, we observe a strong-coupling phase in which the system\ndevelops a mass gap without breaking any lattice symmetry. This symmetric\nstrong-coupling phase is separated from the symmetric weak-coupling phase by a\nnarrow region of four-fermi coupling in which the system exhibits long-range\ncorrelations."
    },
    {
        "anchor": "Towards SU(2) invariant formulation of the monopole confinement\n  mechanism: The type of the vacuum is studied numerically in the maximally Abelian (MA)\ngauge and in the Landau (LA) gauge of SU(2) gluodynamics. The type of the\nvacuum is determined by a ratio between the dual coherence and the dual\npenetration lengths. The dual penetration length is determined from\ncorrelations between Wilson loops and electric fields in both gauges. The dual\ncoherence length is found from correlations between Wilson loops and\ndimension-2 operators both in the MA and the LA gauges. This determination of\nthe coherence length is supported by theoretical and numerical observation that\nthe dimension-2 gluon operators in the studied gauges have a strong correlation\nwith the monopole current determined in the MA gauge. We find numerically that\nthe dual penetration lengths and the dual coherence lengths in the LA and the\nMA gauges are almost the same. Therefore we conclude, that in both gauges the\ntype of the vacuum in the confinement phase is near to the border between the\ntype 1 and the type 2 dual superconductors.",
        "positive": "Radial Correlations between two quarks: In nuclear many-body problems the short-range correlation between two\nnucleons is well described by the corresponding correlation in the {two}-body\nproblem. Therefore, as a first step in any attempt at an analogous description\nof many-quark systems, it is necessary to know the two-quark correlation. With\nthis in mind, we study the light quark distribution in a heavy-light meson with\na static heavy quark. The charge and matter radial distributions of these\nheavy-light mesons are measured on a lattice with a light quark mass about that\nof the strange quark. Both distributions can be well fitted upto r approx 0.7\nfm with the exponential form w_i^2(r), where w_i(r)=A exp(-r/r_i). For the\ncharge(c) and matter(m) distributions r_c approx 0.32(2) fm and r_m \\approx\n0.24(2) fm. We also discuss the normalisation of the total charge (defined to\nbe unity in the continuum limit) and matter integrated over all space, finding\n1.30(5) and 0.4(1) respectively for a lattice spacing approx 0.17 fm."
    },
    {
        "anchor": "Fate of the Tetraquark Candidate Zc(3900) from Lattice QCD: The possible exotic meson $Z_{c}(3900)$, found in $e^+ e^-$ reactions, is\nstudied by the method of coupled-channel scattering in lattice QCD. The\ninteraction among $\\pi J/\\psi$, $\\rho \\eta_{c}$ and $\\bar{D}D^{*}$ channels is\nderived from (2+1)-flavor QCD simulations at $m_{\\pi}=410$-$700$ MeV. The\ninteraction is dominated by the off-diagonal $\\pi J/\\psi$-$\\bar{D}D^{*}$ and\n$\\rho \\eta_{c}$-$\\bar{D}D^{*}$ couplings, which indicates that the\n$Z_{c}(3900)$ is not a usual resonance but a threshold cusp.\nSemi-phenomenological analyses with the coupled-channel interaction are\npresented to confirm this conclusion.",
        "positive": "Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: $I=3/2$ $\u03c0K$\n  Scattering Length: In this paper we report on results for the s-wave scattering length of the\n$\\pi$-$K$ system in the $I=3/2$ channel from $N_f=2+1+1$ Lattice QCD. The\ncalculation is based on gauge configurations generated by the European Twisted\nMass Collaboration with pion masses ranging from about $230$ to\n$450\\,\\text{MeV}$ at three values of the lattice spacing. Our main result reads\n$M_{\\pi}\\,a_0^{3/2,\\text{phys}} = -0.059(2)$. Using chiral perturbation theory\nwe are also able to estimate $M_{\\pi}\\,a_0^{1/2,\\text{phys}} = 0.163(3)$. The\nerror includes statistical and systematic uncertainties, and for the latter in\nparticular errors from the chiral and continuum extrapolations."
    },
    {
        "anchor": "Responses of hadrons to chemical potential at finite temperature: We present a framework to compute the responses of hadron masses to the\nchemical potential in lattice QCD simulations. As a first trial, the screening\nmass of the pseudoscalar meson and its first and second responses are\nevaluated. We present results on a $16\\times 8^2\\times 4$ lattice with two\nflavors of staggered quarks below and above $T_c$. The responses to both the\nisoscalar and isovector chemical potentials are obtained. They show different\nbehavior in the low and the high temperature phases, which may be explained as\na consequence of chiral symmetry breaking and restoration, respectively.",
        "positive": "Non-relativistic bound states in a finite volume: We derive general results for the mass shift of bound states with angular\nmomentum l >= 1 in a periodic cubic box in two and three spatial dimensions.\nOur results have applications to lattice simulations of hadronic molecules,\nhalo nuclei, and Feshbach molecules. The sign of the mass shift can be related\nto the symmetry properties of the state under consideration. We verify our\nanalytical results with explicit numerical calculations. Moreover, we comment\non the relations connecting the effective range parameter, the binding momentum\nof a given state and the asymptotic normalization coefficient of the\ncorresponding wave function. We give explicit expressions for this relation in\nthe shallow binding limit."
    },
    {
        "anchor": "Center vortices, magnetic condensate and confinement in a simple gauge\n  system: The confining mechanisms of 't Hooft and Mandelstam have a simple microscopic\nrealization in 3D Z2 gauge theory: the center vortex and the magnetic monopole\ncondensation are associated, in the set of configurations contributing to the\nconfining phase, to the presence of two kinds of infinite clusters. These\ngenerate the area law of the large Wilson loops and the universal finite size\neffects produced by the quantum fluctuations of the bosonic string describing\nthe infrared behavior of the flux tube.",
        "positive": "First-Order Signals in Compact QED with Monopole Suppressed Boundaries: Pure gauge compact QED on hypercubic lattices is considered with periodically\nclosed monopole currents suppressed. We compute observables on sublattices\nwhich are nested around the centre of the lattice in order to locate regions\nwhere translation symmetry is approximately recovered. Our Monte Carlo\nsimulations on $24^4$-lattices give indications for a first-order nature of the\nU(1) phase transition."
    },
    {
        "anchor": "$B_K$ from improved staggered fermions using SU(3) chiral perturbation\n  theory: We present recent progress in our calculation of $B_K$ with improved\nstaggered fermions using chiral extrapolations based on SU(3) staggered chiral\nperturbation theory. We have accumulated significantly higher statistics on the\ncoarse, fine, and ultrafine MILC asqtad lattices. This leads to a reduction in\nstatistical error and an improved continuum extrapolation. Our updated result\nis $\\hat{B}_K = B_K(\\text{RGI}) = 0.737 \\pm 0.003(\\text{stat}) \\pm 0.046\n(\\text{sys})$. This is consistent with the result obtained using chiral\nextrapolations based on SU(2) staggered chiral perturbation theory, although\nthe total error is somewhat larger with the SU(3) analysis.",
        "positive": "Standard-model prediction for direct CP violation in $K\\to\u03c0\u03c0$ decay: We report the first lattice QCD calculation of the complex kaon decay\namplitude $A_0$ with physical kinematics, using a $32^3\\times 64$ lattice\nvolume and a single lattice spacing $a$, with $1/a= 1.3784(68)$ GeV. We find\nRe$(A_0) = 4.66(1.00)(1.26) \\times 10^{-7}$ GeV and Im$(A_0) =\n-1.90(1.23)(1.08) \\times 10^{-11}$ GeV, where the first error is statistical\nand the second systematic. The first value is in approximate agreement with the\nexperimental result: Re$(A_0) = 3.3201(18) \\times 10^{-7}$ GeV while the second\ncan be used to compute the direct CP violating ratio\nRe$(\\varepsilon'/\\varepsilon)=1.38(5.15)(4.59)\\times 10^{-4}$, which is\n$2.1\\sigma$ below the experimental value $16.6(2.3)\\times 10^{-4}$. The real\npart of $A_0$ is CP conserving and serves as a test of our method while the\nresult for Re$(\\varepsilon'/\\varepsilon)$ provides a new test of the\nstandard-model theory of CP violation, one which can be made more accurate with\nincreasing computer capability."
    },
    {
        "anchor": "Study of QCD Phase Diagram with Non-Zero Chiral Chemical Potential: In this paper we report on lattice simulations of SU(3)-QCD with non-zero\nchiral chemical potential. We focus on the influence of the chiral chemical\npotential on the confinement/deconfinement phase transition and the\nbreaking/restoration of chiral symmetry. The simulation is carried out with\ndynamical Wilson fermions. We find that the critical temperature rises as the\nchiral chemical potential grows.",
        "positive": "QCD at nonzero chemical potential: recent progress on the lattice: We summarise recent progress in simulating QCD at nonzero baryon density\nusing complex Langevin dynamics. After a brief outline of the main idea, we\ndiscuss gauge cooling as a means to control the evolution. Subsequently we\npresent a status report for heavy dense QCD and its phase structure, full QCD\nwith staggered quarks, and full QCD with Wilson quarks, both directly and using\nthe hopping parameter expansion to all orders."
    },
    {
        "anchor": "Exact fermion zero-mode for the new calorons: We construct the fermion zero-mode for arbitrary charge one SU(n) calorons\nwith non-trivial holonomy, both in the finite temperature context\n(anti-periodic boundary conditions in time) and in the Kaluza-Klein\ncompactification context (periodic boundary conditions in time). The zero-mode\nis localised on one of the constituent monopoles and we discuss a relation to\nthe Callias index theorem.",
        "positive": "Pseudoscalar decay constants $f_K/f_\u03c0$, $f_D$ and $f_{D_s}$ with $N_f\n  = 2 + 1 + 1$ ETMC configurations: We present a lattice QCD calculation of the pseudoscalar decay constants\n$f_K$, $f_D$ and $f_{D_s}$ performed by the European Twisted Mass Collaboration\nwith $N_f = 2 + 1 + 1$ dynamical fermions. We simulated at three different\nvalues of the lattice spacing, the smallest being approximately $0.06fm$, and\nwith pion masses as small as $210$MeV. Our main results are:\n$f_{K^+}/f_{\\pi^+}=1.183(17)$, $f_{K^+}=154.4(2.1)$MeV,\n$f_{D_s}=242.1(8.3)$MeV, $f_D=201.9(8.0)$MeV, $f_{D_s}/f_D=1.199(25)$ and\n$(f_{D_s}/f_D) / (f_K/f_\\pi) = 1.005(15)$."
    },
    {
        "anchor": "Progress applying density of states for gravitational waves: Many models of composite dark matter feature a first-order confinement\ntransition in the early Universe, which would produce a stochastic background\nof gravitational waves that will be searched for by future gravitational-wave\nobservatories. We present work in progress using lattice field theory to\npredict the properties of such first-order transitions. Targeting SU(N)\nYang--Mills theories, this work employs the Logarithmic Linear Relaxation (LLR)\ndensity of states algorithm to avoid super-critical slowing down at the\ntransition.",
        "positive": "The hadronic light-by-light scattering contribution to the muon\n  anomalous magnetic moment from lattice QCD: We report the first result for the hadronic light-by-light scattering\ncontribution to the muon anomalous magnetic moment with all errors\nsystematically controlled. Several ensembles using 2+1 flavors of physical mass\nM\\\"obius domain-wall fermions, generated by the RBC/UKQCD collaborations, are\nemployed to take the continuum and infinite volume limits of finite volume\nlattice QED+QCD. We find $a_\\mu^{\\rm HLbL} =\n7.87(3.06)_\\text{stat}(1.77)_\\text{sys}\\times 10^{-10}$. Our value is\nconsistent with previous model results and leaves little room for this\nnotoriously difficult hadronic contribution to explain the difference between\nthe Standard Model and the BNL experiment."
    },
    {
        "anchor": "Finite Size Effects in Nucleon Masses in Dynamical QCD: For lattice calculations with light dynamical quarks, finite size effects\nhave become an important aspect. We study finite size effects in nucleon masses\non N_f=2 dynamical lattices of 1-2 fm. Predictions for the finite size effects\nare obtained in one-loop chiral perturbation theory.",
        "positive": "Light hadron spectrum and quark masses: Recent developments in lattice QCD calculations of the light hadron spectrum\nand quark masses are reviewed."
    },
    {
        "anchor": "The pi+ pi+ scattering length from maximally twisted mass lattice QCD: We calculate the s-wave pion-pion scattering length in the isospin I=2\nchannel in lattice QCD for pion masses ranging from 270 Mev to 485 Mev using\ntwo flavors of maximally twisted mass fermions at a lattice spacing of 0.086\nfm. Additionally, we check for lattice artifacts with one calculation at a\nfiner lattice spacing of 0.067 fm. We use chiral perturbation theory at\nnext-to-leading order to extrapolate our results. At the physical pion mass, we\nfind m_pi a_pipi(I=2)=-0.04385(28)(38) for the scattering length, where the\nfirst error is statistical and the second is our estimate of several systematic\neffects.",
        "positive": "Chiral transition temperature and aspects of deconfinement in 2+1 flavor\n  QCD with the HISQ/tree action: We present results on the chiral transition temperature Tc in 2+1 flavor QCD\nextrapolated to the continuum limit and the physical light quark mass. The\nextrapolations are based on the data from simulations on lattices with temporal\nextent Ntau=6, 8 and 12 with the HISQ/tree and Ntau=8 and 12 with the asqtad\naction. The chiral transition is analyzed in terms of universal O(N) scaling\nfunctions. After performing simultaneous asqtad and HISQ/tree continuum\nextrapolation the chiral transition temperature is Tc=154 +/- 9 MeV. We also\ndiscuss the deconfinement aspects of the transition in terms of the\nrenormalized Polyakov loop, fluctuations and correlations of several conserved\ncharges and the trace anomaly."
    },
    {
        "anchor": "A Fresh Look at the Chemical Potential on the Lattice: Lattice techniques are the most reliable ones to investigate the QCD phase\ndiagram in the temperature-baryon density (chemical potential) plane. These\ntechniques are, however, well-known to be saddled with a variety of problems at\nnonzero density. I address here the old question of placing the baryonic\n(quark) chemical potential on the lattice and point out its important\nconsequences for the current and future experimental searches of the QCD\ncritical point.",
        "positive": "Continuum limit of the mobility edge and taste-degeneracy effects in\n  high-temperature lattice QCD with staggered quarks: We study the effects of taste degeneracy on the continuum scaling of the\nlocalization properties of the staggered Dirac operator in high-temperature QCD\nusing numerical simulations on the lattice, focusing in particular on the\nposition of the mobility edge separating localized and delocalized modes at the\nlow end of the spectrum. We find that, if the continuum limit is approached at\nfixed spatial volume, the restoration of taste symmetry leads to sizeable\nsystematic effects on estimates for the mobility edge obtained from spectral\nstatistics, which become larger and larger as the lattice spacing is decreased.\nSuch systematics, however, are found to decrease if the volume is increased at\nfixed lattice spacing. We argue that spectral statistics estimate correctly the\nposition of the mobility edge in the thermodynamic limit at fixed spacing, and\nsupport this with an independent numerical analysis based directly on the\nproperties of the Dirac eigenvectors, that are unaffected by taste degeneracy.\nWe then provide a theoretical argument justifying the exchange of the\nthermodynamic and continuum limits when studying localization. This allows us\nto use spectral statistics to determine the position of the mobility edge, and\nto obtain a controlled continuum extrapolation of the mobility edge for the\nfirst time."
    },
    {
        "anchor": "Complete Monopole Dominance of the Static Quark Potential: In earlier work, we used a gauge independent Abelian Decomposition to show\nthat Abelian degrees of freedom are wholly responsible for the static quark\npotential. The restricted Abelian field can be split into two terms, a Maxwell\nterm and a $\\theta$ (Dirac) term. The $\\theta$ term's contribution to the\nstring tension can be analysed theoretically and numerically, and arises\nbecause of the existence of a certain type of monopole. While the Abelian field\ncan be constructed without gauge fixing, its two component parts are\ngauge-dependent, with a gauge transformation moving the topological features\nfrom one part to another. This allows us to isolate and identify the\ntopological objects responsible for confinement by constructing a gauge where\nthe $\\theta$ term wholly accounts for the string tension. We confirm the\npresence of these monopoles in lattice simulations of SU(2) Yang-Mills theory.",
        "positive": "Numerical investigations of Supersymmetric Yang-Mills Quantum Mechanics\n  with 4 supercharges: We report on our non-perturbative investigations of supersymmetric Yang-Mills\nquantum mechanics with 4 supercharges. We employ two independent numerical\nmethods. First of them is the cut Fock space method whose numerical\nimplementation was recently generalized to include the SU(N) gauge group. It\nallowed us to calculate for the first time the spectrum of the model with SU(3)\nsymmetry in all fermionic sectors. Independently, we implemented the Rational\nHybrid Monte Carlo algorithm and reproduced the accessible part of the\nlow-energy spectrum of the model with SU(2) gauge symmetry. We argue that by\nsimulating at imaginary chemical potential one can get access to observables\ndefined in sectors of Hilbert space with a given quark number."
    },
    {
        "anchor": "Gauge invariance of color confinement due to the dual Meissner effect\n  caused by Abelian monopoles: The mechanism of non-Abelian color confinement is studied in SU(2) lattice\ngauge theory in terms of the Abelian fields and monopoles extracted from\nnon-Abelian link variables without adopting gauge fixing.\n  Firstly, the static quark-antiquark potential and force are computed with the\nAbelian and monopole Polyakov loop correlators, and the resulting string\ntensions are found to be identical to the non-Abelian string tension. These\npotentials also show the scaling behavior with respect to the change of lattice\nspacing.\n  Secondly, the profile of the color-electric field between a quark and an\nantiquark is investigated with the Abelian and monopole Wilson loops. The\ncolor-electric field is squeezed into a flux tube due to monopole supercurrent\nwith the same Abelian color direction. The parameters corresponding to the\npenetration and coherence lengths show the scaling behavior, and the ratio of\nthese lengths, i.e, the Ginzburg-Landau parameter, indicates that the vacuum\ntype is near the border of the type1 and type2 (dual) superconductor.\n  These results are summarized that the Abelian fundamental charge defined in\nan arbitrary color direction is confined inside a hadronic state by the dual\nMeissner effect. As the color-neutral state in any Abelian color direction\ncorresponds to the physical color-singlet state, this effect explains\nnon-Abelian color confinement and supports the existence of a gauge-invariant\nmechanism of color confinement due to the dual Meissner effect caused by\nAbelian monopoles.",
        "positive": "Complex Langevin dynamics and other approaches at finite chemical\n  potential: I review the presence of the sign problem in lattice QCD at nonzero baryon\ndensity and its relation with the overlap and Silver Blaze problems. I then\ndiscuss progress in some cases where the sign problem can be handled, either\nbecause the sign problem is absent or because it is milder than in full QCD.\nSome time is spent on effective three-dimensional models, which can be treated\nwith a variety of methods. I conclude with a discussion of the applicability of\ncomplex Langevin dynamics at nonzero density."
    },
    {
        "anchor": "Spontaneous supersymmetry breaking in the two-dimensional N=1\n  Wess-Zumino model: We study the phase diagram of the two-dimensional N=1 Wess-Zumino model on\nthe lattice using Wilson fermions and the fermion loop formulation. We give a\ncomplete nonperturbative determination of the ground state structure in the\ncontinuum and infinite volume limit. We also present a determination of the\nparticle spectrum in the supersymmetric phase, in the supersymmetry broken\nphase and across the supersymmetry breaking phase transition. In the\nsupersymmetry broken phase we observe the emergence of the Goldstino particle.",
        "positive": "Strong coupling effective theory with heavy fermions: We extend the recently developed strong coupling, dimensionally reduced\nPolyakov-loop effective theory from finite-temperature pure Yang-Mills to\ninclude heavy fermions and nonzero chemical potential by means of a hopping\nparameter expansion. Numerical simulation is employed to investigate the\nweakening of the deconfinement transition as a function of the quark mass. The\ntractability of the sign problem in this model is exploited to locate the\ncritical surface in the (M/T, mu/T, T) space over the whole range of chemical\npotentials from zero up to infinity."
    },
    {
        "anchor": "Structure of Critical Lines in Quenched Lattice QCD with the Wilson\n  Quark Action: The structure of critical lines of vanishing pion mass for the Wilson quark\naction is examined in quenched lattice QCD. The numerical evidence is presented\nthat critical lines spread into five branches beyond beta=5.6-5.7 at zero\ntemperature. It is also shown that critical lines disappear in the deconfined\nphase for the case of finite temperatures.",
        "positive": "New results with colour-sextet quarks: We study QCD with 2 and 3 flavours of colour-sextet quarks. The 2-flavour\ntheory is a candidate Walking Technicolor theory. Since we are attempting to\ndistinguish whether this theory is walking or conformal, we also study the\n3-flavour theory, which is believed to be conformal, for comparison. We\nsimulate lattice QCD with 2 and 3 flavours of colour-sextet staggered quarks at\nfinite temperatures to determine the scales of confinement and chiral-symmetry\nbreaking from the positions of the deconfinement and chiral-symmetry\nrestoration transitions. Unlike the case with fundamental quarks, these\ntransitions are far apart. For 2 flavours the values of beta=6/g^2 for both\ntransitions increase as Ta is decreased from 1/4 to 1/6 to 1/8, as expected for\na theory whose coupling runs to smaller values as the lattice spacing is\ndecreased. However, for the chiral transition, the increase in beta between\nTa=1/4 and Ta=1/6 is much larger than the increase between Ta=1/6 and Ta=1/8.\nThis suggests that between Ta=1/4 and Ta=1/6 we are at strong coupling where\nthe theory is effectively quenched, while between Ta=1/6 and Ta=1/8 we are\nemerging into the weak coupling regime. It will require even smaller Ta values\nto determine whether the running of the chiral-transition coupling is\ncontrolled by asymptotic freedom and the theory walks, or if it reaches a\nnon-zero limit when the transition becomes a bulk transition and the theory is\nconformal. The 3 flavour case at Ta=1/4 and Ta=1/6 behaves similarly to the 2\nflavour case. Since this theory is expected to be conformal, the interpretation\nthat we are seeing strong-coupling behaviour, inaccessible from the\nweak-coupling limit (continuum) is the most likely interpretation."
    },
    {
        "anchor": "QCD equation of state with 2+1 flavors of improved staggered quarks: We report results for the interaction measure, pressure and energy density\nfor nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In\nour simulations we use a Symanzik improved gauge action and the Asqtad $O(a^2)$\nimproved staggered quark action for lattices with temporal extent $N_t=4$ and\n6. The heavy quark mass $m_s$ is fixed at approximately the physical strange\nquark mass and the two degenerate light quarks have masses $m_{ud}\\approx0.1\nm_s$ or $0.2 m_s$. The calculation of the thermodynamic observables employs the\nintegral method where energy density and pressure are obtained by integration\nover the interaction measure.",
        "positive": "Modified SO(3) Lattice Gauge Theory at non zero T with Parallel\n  Tempering: Monopole and Vortex Condensation: The deconfinement transition is studied close to the continuum limit of SO(3)\nlattice gauge theory. High barriers for tunnelling among different twist\nsectors causing loss of ergodicity for local update algorithms are circumvented\nby means of parallel tempering. We compute monopole and center vortex free\nenergies both within the confining phase and through the deconfinement\ntransition. We discuss in detail the general problem of defining order\nparameters for adjoint actions."
    },
    {
        "anchor": "Developments in the position-space approach to the HLbL contribution to\n  the muon $g-2$ on the lattice: The measurement of the anomalous magnetic moment of the muon and its\nprediction allow for a high-precision test of the Standard Model (SM). In this\nproceedings article we present ongoing work combining lattice QCD and continuum\nQED in order to determine an important SM contribution to the magnetic moment,\nthe hadronic light-by-light contribution. We compute the quark-connected\ncontribution in the Mainz position-space approach and investigate the\nlong-distance part of our data using calculations of the $\\pi^0$-pole and\ncharged pion loop contributions.",
        "positive": "Lattice Improvement in Lattice Effective Field Theory: Lattice calculations using the framework of effective field theory have been\napplied to a wide range few-body and many-body systems. One of the challenges\nof these calculations is to remove systematic errors arising from the nonzero\nlattice spacing. Fortunately, the lattice improvement program pioneered by\nSymanzik provides a formalism for doing this. While lattice improvement has\nalready been utilized in lattice effective field theory calculations, the\neffectiveness of the improvement program has not been systematically\nbenchmarked. In this work we use lattice improvement to remove lattice errors\nfor a one-dimensional system of bosons with zero-range interactions. We\nconstruct the improved lattice action up to next-to-next-to-leading order and\nverify that the remaining errors scale as the fourth power of the lattice\nspacing for observables involving as many as five particles. Our results\nprovide a guide for increasing the accuracy of future calculations in lattice\neffective field theory with improved lattice actions."
    },
    {
        "anchor": "The Free Energy of Spherical Bubbles in Lattice SU(3) Gauge Theory: We study the coefficients of the expansion $F(R) = 1/3 c_3 R^3 + 1/2 c_2 R^2\n+ c_1 R$ of the free energy of spherical bubbles at $T=T_c$ in pure glue QCD\nusing lattice Monte Carlo techniques. The coefficient $c_3$ vanishes at $T=T_c$\nand our results suggest that the sign and the order of magnitude of $c_1$ is in\nagreement with the value $c_1=\\pm 32\\pi T_c^2/9$ (- for hadronic bubbles in\nquark phase, + for quark bubbles in hadronic phase) computed by Mardor and\nSvetitsky from the MIT bag model. The parameter $c_2$ is small in agreement\nwith earlier determinations.",
        "positive": "Non-analyticity in scale in the planar limit of QCD: Using methods of numerical Lattice Gauge Theory we show that in the limit of\na large number of colors, properly regularized Wilson loops have an eigenvalue\ndistribution which changes non-analytically as the overall size of the loop is\nincreased. This establishes a large-N phase transition in continuum planar\ngauge theory, a fact whose precise implications remain to be worked out."
    },
    {
        "anchor": "Topological Susceptibility in Two Flavors Lattice QCD with the Optimal\n  Domain-Wall Fermion: We determine the topological susceptibility of the gauge configurations\ngenerated by lattice simulations using two flavors of optimal domain-wall\nfermion on the $ 16^3 \\times 32 $ lattice with length 16 in the fifth\ndimension, at the lattice spacing $ a \\simeq 0.1 $ fm. Using the adaptive\nthick-restart Lanczos algorithm, we project the low-lying eigenmodes of the\noverlap Dirac operator, and obtain the topological charge of each\nconfiguration, for eight ensembles with pion masses in the range $ 220-550 $\nMeV. From the topological charge, we compute the topological susceptibility and\nthe second normalized cumulant. Our result of the topological susceptibility\nagrees with the sea-quark mass dependence predicted by the chiral perturbation\ntheory and provides a determination of the chiral condensate,\n$\\Sigma^{\\bar{MS}}(2 GeV)=[259(6)(7) MeV]^3 $, and the pion decay constant\n$F_\\pi = 92(12)(2)$ MeV.",
        "positive": "Charmonium resonances from 2+1 flavor CLS lattices: Many exotic charmonium resonances have been identified recently in\nexperiment, however their nature and properties are mostly unknown. Algorithmic\nand theoretical progress in lattice calculations has enabled reliable numerical\ninvestigation of the spectrum below the strong decay threshold, while the study\nof charmonium resonances remains an open challenge. The main difficulty to\novercome is the presence of many open decay channels which are coupled\ntogether, resulting in a complex finite volume quantization condition. We\nreport on our recent progress towards the determination of single-channel and\ncoupled-channel scattering matrices in the scalar and vector channels on CLS\nensembles. We also present an update concerning the study of the charmonium\nspectrum in moving frames."
    },
    {
        "anchor": "Nucleon-Nucleon Potential and its Non-locality in Lattice QCD: By the quenched lattice QCD simulation for two nucleons with finite\nscattering energy, validity of the delivative expansion of the general\nnucleon-nucleon potential U(r,r') = V(r, {\\nabla}_r) \\delta^3(r-r') is studied.\nThe relative kinetic energy between two nucleons is introduced through the\nanti-periodic boundary condition in the spatial directions. On a hypercubic\nlattice with the lattice spacing a ~ 0.137 fm and the spatial extent L_s ~ 4.4\nfm with the pion mass m_{\\pi} ~ 530 MeV, the local potentials for two different\nenergies (E ~ 0 MeV and 45 MeV) are compared and found to be identical within\nstatistical errors, which validates the local approximation of U(r,r') up to\nE=45 MeV for the central and tensor potentials. Central potentials in the\nspin-singlet channel for different orbital angular momentums (l=0 and l=2) at E\n~ 45 MeV are also found to be the same within the errors, which also supports\nthe local approximation.",
        "positive": "Towards the phase diagram of cold and dense heavy QCD: The thermodynamics of QCD with sufficiently heavy dynamical quarks can be\ndescribed by a three-dimensional Polyakov loop effective theory, obtained after\na truncated character and hopping expansion. We investigate the resulting phase\ndiagram for low temperatures by mean field methods. Taking into account\nchemical potentials for both baryon number and isospin, we obtain clear signals\nfor a liquid-gas type transition to baryon matter at $\\mu_I=0$ and a\nBose-Einstein condensation transition at $\\mu_B=0$, as well as for their\nconnection when both chemical potentials are non-zero."
    },
    {
        "anchor": "Lattice quantum gravity with scalar fields: We consider the four-dimensional Euclidean dynamical triangulations lattice\nmodel of quantum gravity based on triangulations of $S^{4}$. We couple it\nminimally to a scalar field in the quenched approximation. Our results suggest\na multiplicative renormalization for the mass of the scalar field which is\nconsistent with the shift symmetry of the discretized lattice action. We\ndiscuss the possibility of measuring the mass anomalous dimension and the\ngravitational binding energy between two scalar test particles, where a\nnegative bound state energy would imply that this model has an attractive\ngravitational force.",
        "positive": "Long-distance contributions to weak amplitudes: The calculation of the long-distance contribution to the $K^0-\\bar{K}^0$ mass\nmatrix is divided into three parts: First, the calculation of the matrix\nelement between kaon states of the product of two space-time integrated,\n$\\Delta S=1$, four-quark weak operators. Second an RI/MOM subtraction to remove\nthe short distance part of this matrix element in a fashion consistent with the\ncalculation of the physical short distance part. Third an application of the\nLellouch-Luscher method, generalized to second order in the weak interactions,\nto control finite volume errors. Such an approach promises to permit accurate\nlattice calculation of the $K_L$-$K_S$ mass difference and the long-distance\ncontributions to $\\epsilon_K$."
    },
    {
        "anchor": "Hermitizing the HAL QCD potential in the derivative expansion: A formalism is given to hermitize the HAL QCD potential, which needs to be\nnon-hermitian except the leading order (LO) local term in the derivative\nexpansion as the Nambu-Bethe-Salpeter (NBS) wave functions for different\nenergies are not orthogonal to each other. It is shown that the non-hermitian\npotential can be hermitized order by order to all orders in the derivative\nexpansion. In particular, the next-to-leading order (NLO) potential can be\nexactly hermitized without approximation. The formalism is then applied to a\nsimple case of $\\Xi \\Xi (^{1}S_{0}) $ scattering, for which the HAL QCD\ncalculation is available to the NLO. The NLO term gives relatively small\ncorrections to the scattering phase shift and the LO analysis seems justified\nin this case. We also observe that the local part of the hermitized NLO\npotential works better than that of the non-hermitian NLO potential. The\nhermitian version of the HAL QCD potential is desirable for comparing it with\nphenomenological interactions and also for using it as a two-body interaction\nin many body systems.",
        "positive": "GPDs in asymmetric frames: It is often taken for granted that Generalized Parton Distributions (GPDs)\nare defined in the \"symmetric\" frame, where the transferred momentum is\nsymmetrically distributed between the incoming/outgoing hadrons. However, such\nframes pose computational challenges for the lattice QCD practitioners. In\nthese proceedings, we lay the foundation for lattice QCD calculations of GPDs\nin \"asymmetric\" frames, where the transferred momentum is not symmetrically\ndistributed between the incoming/outgoing hadrons. The novelty of our work\nrelies on the parameterization of the matrix elements in terms of\nLorentz-invariant amplitudes, which not only helps in establishing relations\nbetween the said frames but also helps in isolating higher-twist\ncontaminations. As an example, we focus on the unpolarized GPDs for spin-1/2\nparticles."
    },
    {
        "anchor": "Short flow-time coefficients of CP-violating operators: Measurements of a permanent neutron electric dipole moment (EDM) potentially\nprobe Beyond-the-Standard Model (BSM) sources of CP-violation. At low energy\nthe CP-violating BSM interactions are parametrized by flavor-conserving\nCP-violating operators of dimension higher than four. QCD calculations of the\nnucleon matrix elements of these operators are required to fully reconstruct\nthe sources and magnitudes of the different CP-violating contributions to the\nnucleon EDM. Herein we study the quark-chromo electric dipole moment (qCEDM)\noperator and the three-gluon Weinberg operator. The non-perturbative\ndetermination, using lattice QCD, of the nucleon matrix elements of these\nCP-violating operators is hampered by their short-distance behavior. Under\nrenormalization these operators mix with lower dimensional operators, which\ninduces power divergences in the lattice spacing, as the continuum limit is\napproached. We study the short-distance behavior of the qCEDM and the Weinberg\noperators using the gradient flow. We perform a short flow time expansion and\ndetermine, in perturbation theory, the expansion coefficients of the\nlinearly-divergent terms stemming from the mixing with the pseudoscalar density\nand the topological charge, confirming the expectations of the operator product\nexpansion. We introduce a new method to perform calculations at non-zero\nflow-time for arbitrary values of the external momenta. This method allows us\nto work in four dimensions for most of the calculations described in this\npaper, avoiding the complications associated with defining $\\gamma_5$ in\ngeneric d dimensions. We show that leading contributions in the external\nmomenta can be reproduced by defining $\\gamma_5$ using the 't\nHooft-Veltman-Breitenlohner-Maison scheme.",
        "positive": "Dirac-K\u00e4hler fermions and exact lattice supersymmetry: We discuss a new approach to putting supersymmetric theories on the lattice.\nThe basic idea is to start from a {\\it twisted} formulation of the underlying\nsupersymmetric theory in which the fermions are represented as grassmann valued\nantisymmetric tensor fields. The original supersymmetry algebra is replaced by\na twisted algebra which contains a scalar nilpotent supercharge $Q$.\nFurthermore the action of the theory can then be written as the $Q$-variation\nof some function. The case of ${\\cal N}=2$ super Yang-Mills theory in two\ndimensions is discussed in some detail. We then present our proposal for\ndiscretizing this theory and derive the resultant lattice action. The latter is\nlocal, free of spectrum doubling, gauge invariant and preserves the scalar\nsupercharge invariance exactly. Some preliminary numerical results are then\npresented. The approach can be naturally generalized to yield a lattice action\nfor ${\\cal N}=4$ super Yang-Mills in four dimensions."
    },
    {
        "anchor": "Determination of the renormalized heavy-quark mass in Lattice QCD: We study on the lattice the correlator of heavy-quark currents in the\nvicinity of vanishing momentum. The renormalized charmed quark mass, the\nrenormalized strong coupling constant and gluon condensate can be defined in\nterms of the derivatives of that correlator at zero momentum. We analyze\nquenched Monte-Carlo data on a small lattice $8^3*16$ for $\\beta=6$. We\ngeneralize dispersion relations to the lattice theory in a simple way and use\nthem successfully to fit the correlator at both small and large distances. We\nfit the short-distance part of the correlator with the relevant expressions of\nperturbative QCD on the lattice and obtain the value of the renormalized quark\nmass $m_c^{\\bar{MS}}(m_c)\\,=\\,1.20(4)\\,GeV$.",
        "positive": "The Improvement Program in Nonrelativistic Lattice QCD: Progress in the improvement program in nonrelativistic lattice QCD is\noutlined. The leading radiative corrections to the heavy-quark mass\nrenormalization, energy shift, and two important kinetic coupling coefficients\nare presented. The reliability of tadpole-improved perturbation theory in\ndetermining the energy shift and mass renormalization is demonstrated."
    },
    {
        "anchor": "Scalar field Restricted Boltzmann Machine as an ultraviolet regulator: Restricted Boltzmann Machines (RBMs) are well-known tools used in Machine\nLearning to learn probability distribution functions from data. We analyse RBMs\nwith scalar fields on the nodes from the perspective of lattice field theory.\nStarting with the simplest case of Gaussian fields, we show that the RBM acts\nas an ultraviolet regulator, with the cutoff determined by either the number of\nhidden nodes or a model mass parameter. We verify these ideas in the scalar\nfield case, where the target distribution is known, and explore implications\nfor cases where it is not known using the MNIST data set. We also demonstrate\nthat infrared modes are learnt quickest.",
        "positive": "Dual Abrikosov vortex between confined charges: We show that the dual Abrikosov vortex between quark and antiquark in Abelian\nProjected SU(2) gauge theory is insensitive to truncation of all loops except\nthe large monopole cluster noted by Hart and Teper. As the transverse distance\nincreases, the discrepancy decreases, suggesting that the London penetration\ndepth determined by the tail is invariant under the truncation of short loops."
    },
    {
        "anchor": "On the continuum limit of the lattice chiral anomaly trace relation: Different aspects concerning the rigorous definition of the traces and\ndeterminants of the operators involved in a procedure ---proposed by Neuberger\nand others--- for avoiding fermion doublers on the lattice, are considered. A\nresult of the analysis is that it seems unclear that the consequences derived\nfrom the independent treatment of the traces of the two operators contributing\nto the index relation on the lattice, as carried out in recent manuscripts, can\nbe given rigorous mathematical footing, in particular, that these treatments\ncan commute with the continuum limit ---the lattice regularized trace being\nadditive all the way through the limit, while the otherwise regularized trace\nin the continuum is not so.",
        "positive": "Hagedorn spectrum and thermodynamics of SU(2) and SU(3) Yang-Mills\n  theories: We present a high-precision lattice calculation of the equation of state in\nthe confining phase of SU(2) Yang-Mills theory. We show that the results are\ndescribed very well by a gas of massive, non-interacting glueballs, provided\none assumes an exponentially growing Hagedorn spectrum. The latter can be\nderived within an effective bosonic closed-string model, leading to a\nparameter-free theoretical prediction, which is in perfect agreement with our\nlattice results. Furthermore, when applied to SU(3) Yang-Mills theory, this\neffective model accurately describes the lattice results reported by Bors\\'anyi\net al. in JHEP 07 (2012) 056."
    },
    {
        "anchor": "The Isgur-Wise Limit on the Lattice: We construct the Isgur-Wise limit of QCD in a form appropriate to lattice\ngauge theory techniques. The formulation permits a calculation of heavy quark\nprocesses even when the momentum transfers are much larger than the inverse\nlattice spacing. Applications include semi-leptonic heavy quark decay and\nscattering processes, including the computation of the nonperturbative part of\nthe Isgur-Wise universal function.",
        "positive": "Critical behaviour of the O(3) nonlinear sigma model with topological\n  term at theta=pi from numerical simulations: We investigate the critical behaviour at theta=pi of the two-dimensional O(3)\nnonlinear sigma model with topological term on the lattice. Our method is based\non numerical simulations at imaginary values of theta, and on scaling\ntransformations that allow a controlled analytic continuation to real values of\ntheta. Our results are compatible with a second order phase transition, with\nthe critical exponent of the SU(2)_1 Wess-Zumino-Novikov-Witten model, for\nsufficiently small values of the coupling."
    },
    {
        "anchor": "Chiral Symmetry Breaking from Center Vortices: We analyze the creation of near-zero modes from would-be zero modes of\nvarious topological charge contributions from classical center vortices in\nSU(2) lattice gauge theory. We show that colorful spherical vortex and\ninstanton configurations have very similar Dirac eigenmodes and also vortex\nintersections are able to give rise to a finite density of near-zero modes,\nleading to chiral symmetry breaking via the Banks-Casher formula. We discuss\nthe influence of the magnetic vortex fluxes on quarks and how center vortices\nmay break chiral symmetry.",
        "positive": "What we are learning about the Quark Structure of Hadrons from Lattice\n  QCD?: Developments in lattice field theory and computer technology have led to\ndramatic advances in the use of lattice QCD to explore the quark structure of\nhadrons. This talk will describe selected examples, including structure\nfunctions, electromagnetic form factors, the nucleon axial charge, the origin\nof the nucleon spin, the transverse structure of the nucleon, and the nucleon\nto Delta transition form factor."
    },
    {
        "anchor": "More about the Grassmann tensor renormalization group: We derive a general formula of the tensor network representation for\n$d$-dimensional lattice fermions with ultra-local interactions, including\nWilson fermions, staggered fermions, and domain-wall fermions. The Grassmann\ntensor is concretely defined with auxiliary Grassmann variables that play a\nrole in bond degrees of freedom. Compared to previous works, our formula does\nnot refer to the details of lattice fermions and is derived by using the\nsingular value decomposition for the given Dirac matrix without any ad-hoc\ntreatment for each fermion. We numerically test our formula for free Wilson and\nstaggered fermions and find that it properly works for them. We also find that\nWilson fermions show better performance than staggered fermions in the tensor\nrenormalization group approach, unlike the Monte Carlo method.",
        "positive": "Miscellanies of $ K^0 - \\bar{K}^0 $ mixing and $ B_K $: We have computed $ B_K $, using two different methods with staggered fermions\non a $ 16^3 \\times 40 $ lattice at $ \\beta = 5.7 $ with two dynamical flavors\nof a mass 0.01. % Using an improved wall source method, we have studied a\nseries of non-degenerate quark antiquark pairs and observed no effect on $ B_K\n$, although effects were seen on the individual terms making up $ B_K $."
    },
    {
        "anchor": "Axial charges of hyperons and charmed baryons using $N_f=2+1+1$ twisted\n  mass fermions: The axial couplings of the low lying baryons are evaluated using a total of\nfive ensembles of dynamical twisted mass fermion gauge configurations. The\nsimulations are performed using the Iwasaki gauge action and two degenerate\nflavors of light quarks, and a strange and a charm quark fixed to approximately\ntheir physical values at two values of the coupling constant. The lattice\nspacings, determined using the nucleon mass, are $a=0.082$ fm and $a=0.065$ fm\nand the simulations cover a pion mass in the range of about 210 MeV to 430 MeV.\nWe study the dependence of the axial couplings on the pion mass in the range of\nabout 210 MeV to 430 MeV as well as the $SU(3)$ breaking effects as we decrease\nthe light quark mass towards its physical value.",
        "positive": "Lattice QCD with Suppressed High Momentum Modes of the Dirac Operator: I define lattice fermions in five Euclidean dimensions and the corresponding\neffective theory in four dimensions. The main properties of these theories\ninclude the suppression of high momentum modes of the lattice Dirac operator\nand their ability to continuously interpolate between quenched and dynamical\nfermions. In particular, the standard formulation of lattice QCD can be viewed\nas a limiting case of the theory."
    },
    {
        "anchor": "Topological charge unfreezing with AMReX: A new approach to the problem of topological freezing in gauge theories is\nintroduced in which a physical volume preserving coarsening of the lattice\ninduces sufficient energy variation in the Hamiltonian to overcome large\ntopological barriers. Though the process is not reversible, the physical volume\npreserving aspect minimises the time spent rethermalisating the lattice after\ncoarsening periods, which we then treat as a new ensemble disjoint from\nprevious runs. We have tested this technique on the pure gauge 2D Schwinger\nmodel and find that topological sampling rates are improved. We also\ndemonstrate that autocorrelation times for extensive observables are restored\nto their pre-coarsening values after coarsening periods over a acceptably short\nsimulation time.",
        "positive": "Isospin breaking and the chiral condensate: With two degenerate quarks, the chiral condensate exhibits a jump as the\nquark masses pass through zero. I discuss how this single transition splits\ninto two Ising like transitions when the quarks are made non-degenerate. The\norder parameter is the expectation of the neutral pion field. The transitions\nrepresent long distance coherent phenomena occuring without the Dirac operator\nhaving vanishingly small eigenvalues."
    },
    {
        "anchor": "Update: Accurate Determinations of alpha_s from Realistic Lattice QCD: We use lattice QCD simulations, with MILC configurations (including vacuum\npolarization from u, d, and s quarks), to update our previous determinations of\nthe QCD coupling constant. Our new analysis uses results from 6 different\nlattice spacings and 12 different combinations of sea-quark masses to\nsignificantly reduce our previous errors. We also correct for\nfinite-lattice-spacing errors in the scale setting, and for nonperturbative\nchiral corrections to the 22 short-distance quantities from which we extract\nthe coupling. Our final result is alpha_V(7.5GeV,nf=3) = 0.2120(28), which is\nequivalent to alpha_msbar(M_Z,n_f=5)= 0.1183(8). We compare this with our\nprevious result, which differs by one standard deviation.",
        "positive": "Large-N reduction of SU(N) Yang-Mills theory with massive adjoint\n  overlap fermions: We study four dimensional large-N SU(N) Yang-Mills theory coupled to adjoint\noverlap fermions on a single site lattice. Lattice simulations along with\nperturbation theory show that the bare quark mass has to be taken to zero as\none takes the continuum limit in order to be in the physically relevant\ncenter-symmetric phase. But, it seems that it is possible to take the continuum\nlimit with any renormalized quark mass and still be in the center-symmetric\nphysics. We have also conducted a study of the correlations between Polyakov\nloop operators in different directions and obtained the range for the Wilson\nmass parameter that enters the overlap Dirac operator."
    },
    {
        "anchor": "Electromagnetic Form Factors for the $\u039b$(1405): Building on our successful technique to isolate the otherwise-elusive\n$\\Lambda$(1405) using correlation matrix techniques and multiple source and\nsink smearings, we present calculations of the quark sector contributions to\nthe electric form factors of the $\\Lambda$(1405). Using the PACS-CS\n$(2+1)$-flavour full-QCD ensembles available through the ILDG, our calculations\nreveal behaviour consistent with the development of a non-trivial molecular\n$\\overline{K}N$ bound-state component as one approaches the physical values of\nthe $u$ and $d$ quark masses.",
        "positive": "Possible evidence for the mass shift of $\u03b7$' meson at finite\n  temperature: Topological charge distributions of SU(3) gauge theory at finite temperature\nare calculated on the lattice with high statistics in a manner of free from the\nuncertainty of $\\beta$-function. Clear temperature dependence of the\ntopological charge distribution is obtained. Combining the present result with\nthe recent study about the relation between the masses of $\\eta$ meson system\nand the gauge field topology, we obtain $m_{\\eta'}(T)/m_{\\eta'}(0) = 0.86 \\pm\n0.02$ and $0.69 \\pm 0.01$ for $T=0.75 T_c$ and $T=0.93 T_c$, respectively. The\nresult shows the first clear evidence of the mass shift of $\\eta'$ meson at\nfinite temperature."
    },
    {
        "anchor": "Chiral Symmetry Breaking in Planar QED in External Magnetic Fields: We investigate planar quantum electrodynamics (QED) with two degenerate\nstaggered fermions in an external magnetic field on the lattice. We argue that\nin external magnetic fields there is dynamical generation of mass for\ntwo-dimensional massless Dirac fermions in the weak-coupling region. We\nextrapolate our lattice results to the quantum Hall effect in graphene.",
        "positive": "HQET at order 1/m: III. Decay constants in the quenched approximation: We report on the computation of the $B_s$ meson decay constant in Heavy Quark\nEffective Theory on the lattice. The next to leading order corrections in the\nHQET expansion are included non-perturbatively. We estimate higher order\ncontributions to be very small. The results are extrapolated to the continuum\nlimit, the main systematic error affecting the computation is therefore the\nquenched approximation used here. The Generalized Eigenvalue Problem and the\nuse of all-to-all propagators are important technical ingredients of our\napproach that allow to keep statistical and systematic errors under control. We\nalso report on the decay constant $f_{B'_s}$ of the first radially excited\nstate in the $B_s$ sector, computed in the static limit."
    },
    {
        "anchor": "Vacuum structure of gauge theory on lattice with two parallel plaquette\n  action: We perform Monte Carlo simulations of a lattice gauge system with an action\nwhich contains two parallel plaquettes. The action is defined as a product of\ngauge group variables over two parallel plaquettes belonging to a given\nthree-dimensional cube. The peculiar property of this system is that it has\nstrong degeneracy of the vacuum state inherited from corresponding gonihedric\n$Z_2$ gauge spin system. These vacuua are well separated and can not be\nconnected by a gauge transformation. We measure different observables in these\nvacuua and compare their properties.",
        "positive": "Non-perturbative determination of improvement coefficients using\n  coordinate space correlators in $N_f=2+1$ lattice QCD: We determine quark mass dependent order $a$ improvement terms of the form\n$b_Jam$ for non-singlet scalar, pseudoscalar, vector and axialvector currents\nusing correlators in coordinate space on a set of CLS ensembles. These have\nbeen generated employing non-perturbatively improved Wilson Fermions and the\ntree-level L\\\"uscher-Weisz gauge action at $\\beta = 3.4, 3.46, 3.55$ and $3.7$,\ncorresponding to lattice spacings ranging from $a \\approx 0.085$ fm down to\n$0.05$ fm. In the $N_f=2+1$ flavour theory two types of improvement\ncoefficients exist: $b_J$, proportional to non-singlet quark mass combinations,\nand $\\bar{b}_J$ (or $\\tilde{b}_J$), proportional to the trace of the quark mass\nmatrix. Combining our non-perturbative determinations with perturbative\nresults, we quote Pad\\'e approximants parameterizing the $b_J$ improvement\ncoefficients within the above window of lattice spacings. We also give\npreliminary results for $\\tilde{b}_J$ at $\\beta=3.4$."
    },
    {
        "anchor": "Applications of the Stochastic LapH Method: Progress in computing the hadron spectrum in lattice QCD using stochastic\nLapH quark propaga- tors is described. The stochastic LapH algorithm is a\nparticular quark smearing algorithm that also allows the computation of\nall-to-all quark propagators. All-to-all quark propagators are required in our\napproach of using a large set of spatially extended hadron operators and\nexplicit multi- particle operators to access excited states. We report on the\nprogress made in the various isospin channels on 2+1 dynamical, anisotropic\nlattices generated by the Hadron Spectrum Collaboration.",
        "positive": "Absence of sign problem in the (saddle point approximation of the)\n  nilpotency expansion of QCD at finite chemical potential: We have developed a method to derive the (approximate) quark contribution to\nthe fermion free energy of QCD on a lattice, at finite temperature and chemical\npotential, with Kogut-Susskind fermions in the flavor basis. We show here the\nexpression at zero temperature. This result has been obtained at the lowest\norder of the nilpotency expansion. At this order the well known \"sign problem\"\ndoes not arise and the quark contribution to the action can be used as a\nstatistical weight in the Monte Carlo simulations."
    },
    {
        "anchor": "Isovector Axial Charge and Form Factors of Nucleons from Lattice QCD: I present an overview of the calculations of the isovector axial vector form\nfactor of the nucleon, $G_A(Q^2)$, using lattice QCD. Based on a comparison of\nresults from various collaborations, a case is made that lattice results are\nnow consistent within 10\\%. A similar level of uncertainty is found also in the\naxial charge $g_A^{u-d}$, the mean squared axial charge radius, $\\langle r_A^2\n\\rangle$, the induced pseudoscalar charge $g_P^\\ast$, and the pion-nucleon\ncoupling $g_{\\pi NN}$. These lattice results for $G_A(Q^2)$ are already\ncompatible with those obtained from the recent MINER$\\nu$A experiment but lie\n2-3$\\sigma$ higher than the phenomenological extraction from the old\n$\\nu$-deuterium bubble chamber scattering data for $Q^2 > 0.3$~GeV${}^2$. Fits\nto our data show that the dipole ansatz does not have enough parameters to\nparameterize the form factor over the range $0 \\le Q^2 \\le 1$~GeV${}^2$,\nwhereas even a $z^2$ truncation of the $z$-expansion or a low order Pad\\'e are\nsufficient. Looking ahead, lattice QCD calculations will provide increasingly\nprecise results over the range $0 \\le Q^2 \\lesssim 1$~GeV${}^2$, and\nMINER$\\nu$A-like experiments will extend the range to $Q^2 \\sim 2$~GeV${}^2$ or\nhigher. To increase precision of lattice data to the percent level, new\ndevelopments are needed to address two related issues: the exponentially\nfalling signal-to-noise ratio in all nucleon correlation functions and removing\nexcited state contributions. Nevertheless, even with the current methodology,\nsignificant reduction in errors is expected over the next few years with higher\nstatistics data on more ensembles closer to the physical point.",
        "positive": "Expansion Aspect of Color Transparency on the Lattice: The opportunity to observe color transparency (CT) is determined by how\nrapidly a small-sized hadronic wave packet expands. Here we use SU(2) lattice\ngauge theory with Wilson fermions in the quenched approximation to investigate\nthe expansion. The wave packet is modeled by a point hadronic source, often\nused as an interpolating field in lattice calculations. The procedure is to\ndetermine the Euclidean time (t), pion channel, Bethe-Salpeter amplitude\n$\\Psi(r,t)$, and then evaluate $b^2(t)=\\int d^3 r \\Psi(r,t) r^2 sin^2 \\theta\n\\Psi_{\\pi}(r)$. This quantity represents the soft interaction of a small-sized\nwave packet with a pion. The time dependence of $b^2(t)$ is fit as a\nsuperposition of three states, which is found sufficient to reproduce a reduced\nsize wave packet. Using this superposition allows us to make the analytic\ncontinuation required to study the wave packet expansion in real time. We find\nthat the matrix elements of the soft interaction $\\hat b^2$ between the excited\nand ground state decrease rapidly with the energy of the excited state."
    },
    {
        "anchor": "Manifestations of magnetic vortices in equation of state of Yang-Mills\n  plasma: The vacuum of Yang-Mills theory contains singular stringlike objects\nidentified with center (magnetic) vortices. Percolation of magnetic vortices is\nknown to be responsible for the color confinement in the low-temperature phase\nof the theory. In our work we study properties of the vortices at finite\ntemperature using lattice simulations of SU(2) gauge theory. We show that\nmagnetic vortices provide a numerically large contribution to thermodynamic\nquantities of the gluon plasma in Yang-Mills theory. In particular, we observe\nthat in the deconfinement phase at temperatures T_c < T < 3 T_c the magnetic\ncomponent of the gluon plasma produces a negative (ghostlike) contribution to\nthe anomaly of the energy-momentum tensor. In the confinement phase the vortex\ncontribution is positive. The thermodynamical significance of the magnetic\nobjects allows us to suggest that the quark-gluon plasma may contain a\ndeveloped network of magnetic flux tubes. The existence of the vortex network\nmay lead to observable effects in the quark-gluon plasma because the\nchromomagnetic field of the vortices should scatter and drag quarks.",
        "positive": "Excited-state spectroscopy of triply-bottom baryons from lattice QCD: The spectrum of baryons containing three b quarks is calculated in\nnonperturbative QCD, using the lattice regularization. The energies of ten\nexcited bbb states with J^P = 1/2^+, 3/2^+, 5/2^+, 7/2^+, 1/2^-, and 3/2^- are\ndetermined with high precision. A domain-wall action is used for the up-, down-\nand strange quarks, and the bottom quarks are implemented with NRQCD. The\ncomputations are done at lattice spacings of a \\approx 0.11 fm and a \\approx\n0.08 fm, and the results demonstrate the improvement of rotational symmetry as\na is reduced. A large lattice volume of (2.7 fm)^3 is used, and extrapolations\nof the bbb spectrum to realistic values of the light sea-quark masses are\nperformed. All spin-dependent energy splittings are resolved with total\nuncertainties of order 1 MeV, and the dependence of these splittings on the\ncouplings in the NRQCD action is analyzed."
    },
    {
        "anchor": "Perturbative lattice artefacts in the SF coupling for\n  technicolor-inspired models: Viable candidate theories for electroweak dynamical symmetry breaking are\nexpected to show (near) conformal behaviour in order to accommodate current\nphenomenological constraints. In principle, renormalisation group studies using\nfinite volume renormalisation schemes are well-suited to verify this property\nin a given model. The most practical schemes are based on the Schrodinger\nfunctional (SF), but suffer from potentially large O(a) effects. Some care has\nto be taken to remove these effects and to set up a scheme where cutoff effects\nare small and under control. We here take a step in this direction by analysing\nvarious set-ups for the SF coupling at one-loop order in perturbation theory.",
        "positive": "Topological defects and equation of state of gluon plasma: We show that the degrees of freedom associated with magnetic monopole- and\nvortexlike gluonic configurations make a strong contribution to the anomaly of\nthe energy-momentum tensor of Yang-Mills theory in the deconfinement phase\nimmediately above the critical temperature. As is well known in\nzero-temperature Yang-Mills theory, the monopoles and vortices are constituents\nof a generic gluonic object in which the two neighbor monopoles are connected\ntogether by a segment of vortex string. Our results provide evidence that the\nmonopole-vortex chains in SU(2) gauge theory and their SU(3) counterparts, the\nmonopole-vortex nets, are thermodynamically relevant degrees of freedom in the\ngluonic plasma."
    },
    {
        "anchor": "Four fermion operators and the search for BSM Physics: We report on Monte Carlo simulations focused on elucidating the phase\nstructure of a SU(2) gauge theory containing $N_f$ Dirac fermion flavors\ntransforming in the fundamental representation of the group and interacting\nthrough an additional chirally invariant four fermion term. Pairs of physical\nflavors are implemented using the two tastes present in a reduced staggered\nfermion formulation of the theory with the Yukawa interactions necessary for\ngenerating the four fermion term preserving the usual shift symmetries. We\nobserve a crossover in the behavior of the chiral condensate for strong four\nfermi coupling associated with the generation of a dynamical mass for the\nfermions. At weak gauge coupling this crossover is consistent with the usual\ncontinuous phase transition seen in the pure (ungauged) NJL model. However, if\nthe gauge coupling is strong enough to cause confinement we observe a much more\nrapid crossover in the chiral condensate consistent with a first order phase\ntransition.",
        "positive": "From Ji to Jaffe-Manohar orbital angular momentum in Lattice QCD using a\n  direct derivative method: A Lattice QCD approach to quark orbital angular momentum in the proton based\non generalized transverse momentum-dependent parton distributions (GTMDs) is\nenhanced methodologically by incorporating a direct derivative technique. This\nimprovement removes a significant numerical bias that had been seen to afflict\nresults of a previous study. In particular, the value obtained for Ji quark\norbital angular momentum is reconciled with the one obtained independently via\nJi's sum rule, validating the GMTD approach. Since GTMDs simultaneously contain\ninformation about the quark impact parameter and transverse momentum, they\npermit a direct evaluation of the cross product of the latter. They are defined\nthrough proton matrix elements of a quark bilocal operator containing a Wilson\nline; the choice in Wilson line path allows one to continuously interpolate\nfrom Ji to Jaffe-Manohar quark orbital angular momentum. The latter is seen to\nbe significantly enhanced in magnitude compared to Ji quark orbital angular\nmomentum, confirming previous results."
    },
    {
        "anchor": "Phase structure of U(1) lattice gauge theory with monopole term: We investigate four-dimensional compact U(1) lattice gauge theory with a\nmonopole term added to the Wilson action. First we consider the phase structure\nat negative $\\beta$, revealing some properties of a third phase region there,\nin particular the existence of a number of different states. Then our present\nstudies concentrate on larger values of the monopole coupling $\\lambda$ where\nthe confinement-Coulomb phase transition turns out to become of second order.\nPerforming a finite-size analysis we find that the critical exponent $\\nu$ is\nclose to, however, different from the gaussian value and that in the range\nconsidered $\\nu$ increases somewhat with $\\lambda$.",
        "positive": "Quenched divergences in the deconfined phase of SU(2) gauge theory: The spectrum of the overlap Dirac operator in the deconfined phase of\nquenched gauge theory is known to have three parts: exact zeros arising from\ntopology, small nonzero eigenvalues that result in a non-zero chiral\ncondensate, and the dense bulk of the spectrum, which is separated from the\nsmall eigenvalues by a gap. In this paper, we focus on the small nonzero\neigenvalues in an SU(2) gauge field background at $\\beta=2.4$ and $N_T=4$. This\nlow-lying spectrum is computed on four different spatial lattices ($12^3$,\n$14^3$, $16^3$, and $18^3$). As the volume increases, the small eigenvalues\nbecome increasingly concentrated near zero in such a way as to strongly suggest\nthat the infinite volume condensate diverges."
    },
    {
        "anchor": "Leading isospin-breaking corrections to pion, kaon and charmed-meson\n  masses with Twisted-Mass fermions: We present a lattice computation of the isospin-breaking corrections to\npseudoscalar meson masses using the gauge configurations produced by the\nEuropean Twisted Mass collaboration with $N_f = 2 + 1 + 1$ dynamical quarks at\nthree values of the lattice spacing ($a \\simeq 0.062, 0.082$ and $0.089$ fm)\nwith pion masses in the range $M_\\pi \\simeq 210 - 450$ MeV. The strange and\ncharm quark masses are tuned at their physical values. We adopt the RM123\nmethod based on the combined expansion of the path integral in powers of the\n$d$- and $u$-quark mass difference ($\\widehat{m}_d - \\widehat{m}_u$) and of the\nelectromagnetic coupling $\\alpha_{em}$. Within the quenched QED approximation,\nwhich neglects the effects of the sea-quark charges, and after the\nextrapolations to the physical pion mass and to the continuum and infinite\nvolume limits, we provide results for the pion, kaon and (for the first time)\ncharmed-meson mass splittings, for the prescription-dependent parameters\n$\\epsilon_{\\pi^0}$, $\\epsilon_\\gamma(\\overline{MS}, 2~\\mbox{GeV})$,\n$\\epsilon_{K^0}(\\overline{MS}, 2~\\mbox{GeV})$, related to the violations of the\nDashen's theorem, and for the light quark mass difference $(\\widehat{m}_d -\n\\widehat{m}_u)(\\overline{MS}, 2~\\mbox{GeV})$.",
        "positive": "Short distance singularities and automatic O($a$) improvement: the cases\n  of the chiral condensate and the topological susceptibility: Short-distance singularities in lattice correlators can modify their Symanzik\nexpansion by leading to additional O($a$) lattice artifacts. At the example of\nthe chiral condensate and the topological susceptibility, we show how to\naccount for these lattice artifacts for Wilson twisted mass fermions and show\nthat the property of automatic O($a$) improvement is preserved at maximal\ntwist."
    },
    {
        "anchor": "Entanglement entropy from non-equilibrium lattice simulations: Entanglement entropy encodes important features of strongly interacting\nquantum many-body systems and gauge theories, but its analytical study is still\nlimited to systems with high level of symmetry. This motivates the search for\nefficient techniques to investigate this quantity numerically, through Monte\nCarlo calculations on the lattice. In this contribution, we discuss the\ncomputation of the entropic c-function by means of an algorithm based on\nJarzynski's equality, which is an exact theorem from non equilibrium\nstatistical mechanics. After presenting benchmark results for the Ising model\nin two dimensions, where our algorithm successfully reproduces the analytical\npredictions from conformal field theory, we discuss its generalization to the\nthree-dimensional Ising model, for which we were able to extract universal\nterms beyond the area law. Finally we point out some future generalizations of\nthis calculation.",
        "positive": "$t \\to 0$ extrapolation function in SF$t$X method for the\n  energy-momentum tensor: We theoretically clarify the functional form to be used in $t \\to 0$\nextrapolation in the small flow time expansion (SF$t$X) method for the\nenergy-momentum tensor (EMT), which facilitates lattice simulation of the EMT\nbased on the gradient flow. We argue that in the $t \\to 0$ extrapolation\nanalysis, lattice data should be fitted by a power function in $g(\\mu(t))$, the\nflow time dependent running coupling, where the power is determined by the\nperturbation order we consider. From actual lattice data, we confirm the\nvalidity of the extrapolation function. Using the new extrapolation function,\nwe present updated lattice results for thermodynamics quantities in quenched\nQCD; our results are consistent with the previous study [arXiv:1812.06444] but\nwe obtain smaller errors due to reduction of systematic errors."
    },
    {
        "anchor": "Thermodynamics of two flavor QCD from imaginary chemical potentials: We study QCD thermodynamics in presence of two independent imaginary chemical\npotentials coupled to two degenerate flavors of staggered quarks. Analytic\ncontinuation is used to determine non-linear susceptibilities, to test the\nHadron Resonance Gas (HRG) model below the zero density critical temperature,\nTc, and to determine the average phase factor of the fermion determinant.\nDeviations from HRG predictions, of the order of a few percent, are clearly\nvisible for temperatures T > 0.95 Tc. The determination of non-linear\nsusceptibilities, using different interpolating functions for analytic\ncontinuation, gives consistent results and in agreement with Taylor expansion\ncomputations, apart from some systematic effects at or right above Tc. Results\nfor the average phase factor are compared with the predictions of Chiral\nPerturbation Theory; below Tc we are able to distinguish the contribution of\ndifferent hadron states, which is positive (i.e. tends to mitigate the sign\nproblem) in the case of baryons.",
        "positive": "Measures of critical exponents in the four dimensional site percolation: Using finite-size scaling methods we measure the thermal and magnetic\nexponents of the site percolation in four dimensions, obtaining a value for the\nanomalous dimension very different from the results found in the literature. We\nalso obtain the leading corrections-to-scaling exponent and, with great\naccuracy, the critical density."
    },
    {
        "anchor": "Random matrix model of QCD at finite density and the nature of the\n  quenched limit: We use a random matrix model to study chiral symmetry breaking in QCD at\nfinite chemical potential $\\mu$. We solve the model and compute the eigenvalue\ndensity of the Dirac matrix on a complex plane. A naive ``replica trick'' fails\nfor $\\mu\\neq0$: we find that quenched QCD is not a simple $n\\to0$ limit of QCD\nwith $n$ quarks. It is the limit of a theory with $2n$ quarks: $n$ quarks with\noriginal action and $n$ quarks with conjugate action. The results agree with\nearlier studies of lattice QCD at $\\mu\\neq0$ and provide a simple analytical\nexplanation of a long-standing puzzle.",
        "positive": "Diseases with rooted staggered quarks: Calculations using staggered quarks augmented with a root of the fermion\ndeterminant to reduce doubling give a qualitatively incorrect behavior in the\nsmall quark mass region. Attempts to circumvent this problem for the continuum\nlimit involve an unproven combination of unphysical states, a loss of\nunitarity, and a rather peculiar non-commutation of limits."
    },
    {
        "anchor": "Connected Correlators in Random Geometries: We analyze correlation functions in a toy model of a random geometry\ninteracting with matter. We show that in general the connected correlator will\ncontain a long-range scaling part which is in some sense a remnant of the\ndisconnected part. This result supports the previously conjectured general form\nof correlation functions. We discuss the interplay between matter and geometry\nand the role of the symmetry in the matter sector.",
        "positive": "Chiral Analysis of Quenched Baryon Masses: We extend to quenched QCD an earlier investigation of the chiral structure of\nthe masses of the nucleon and the delta in lattice simulations of full QCD.\nEven after including the meson-loop self-energies which give rise to the\nleading and next-to-leading non-analytic behaviour (and hence the most rapid\nvariation in the region of light quark mass), we find surprisingly little\ncurvature in the quenched case. Replacing these meson-loop self-energies by the\ncorresponding terms in full QCD yields a remarkable level of agreement with the\nresults of the full QCD simulations. This comparison leads to a very good\nunderstanding of the origins of the mass splitting between these baryons."
    },
    {
        "anchor": "Interface Tension of the Electroweak Phase Transition: In our nonperturbative lattice investigation we study the interface tension\nof the finite-temperature electroweak phase transition. In this analysis the\nHiggs mass has been chosen to be about $35$ GeV. At the transition point of a\nfinite volume system, tunnelling between the symmetric and the Higgs phase\ntakes place. This phenomenon leads to a splitting of the ground state, which\ncan be used to determine the interface tension. The result obtained this way\nagrees with the result of the two-coupling method and with the prediction of\nthe perturbative approach.",
        "positive": "Mixed Action Simulations on Staggered Background; Interpretation and\n  Result for the 2-flavor QCD Chiral Condensate: Growing evidence indicates that in the continuum limit the rooted staggered\naction is in the correct QCD universality class, the non-local terms arising\nfrom taste breaking can be viewed as lattice artifacts. In this paper we\nconsider the 2-flavor Asqtad staggered action at a lattice spacing of\napproximately 0.13 fm and probe the properties of the staggered configurations\nby an overlap valence Dirac operator. By comparing the distribution of the\noverlap eigenmodes to continuum QCD predictions we investigate if/when the\nlattice artifacts are small as a function of the staggered quark mass. We\ndefine a matching overlap quark mass where the lattice corrections are minimal\nfor the topological susceptibility and from the eigenmode distribution we\npredict the 2-flavor chiral condensate. Our results indicate that the staggered\nconfigurations are consistent with 2-flavor continuum QCD up to small lattice\nartifacts, and predict a consistent value for the infinite volume chiral\ncondensate."
    },
    {
        "anchor": "Properties of Overlap and Domain Wall Fermions in the 2+1D Thirring\n  Model: We present some results pertaining to partially quenched formulations of the\noverlap/domain wall operator with the Thirring model in 2+1D. Auxiliary fields\nare generated with a Shamir domain wall approach and measurements of\neigenvalues and condensates are contrasted with different overlap operators.\nThe numerical challenge posed by a non-compact formulation is highlighted, and\nthe effective use of lower accuracy sea fermions is demonstrated.",
        "positive": "A variational Monte Carlo algorithm for lattice gauge theories with\n  continuous gauge groups: a study of (2+1)-dimensional compact QED with\n  dynamical fermions at finite density: Lattice gauge theories coupled to fermionic matter account for many\ninteresting phenomena in both high energy physics and condensed matter physics.\nCertain regimes, e.g. at finite fermion density, are difficult to simulate with\ntraditional Monte Carlo algorithms due to the so-called sign-problem. We\npresent a variational, sign-problem-free Monte Carlo method for lattice gauge\ntheories with continuous gauge groups and apply it to (2+1)-dimensional compact\nQED with dynamical fermions at finite density. The variational ansatz is\nformulated in the full gauge field basis, i.e. without having to resort to\ntruncation schemes for the $U(1)$ gauge field Hilbert space. The ansatz\nconsists of two parts: first, a pure gauge part based on Jastrow-type ansatz\nstates (which can be connected to certain neural-network ansatz states) and\nsecondly, on a fermionic part based on gauge-field dependent fermionic Gaussian\nstates. These are designed in such a way that the gauge field integral over all\nfermionic Gaussian states is gauge-invariant and at the same time still\nefficiently tractable. To ensure the validity of the method we benchmark the\npure gauge part of the ansatz against another variational method and the full\nansatz against an existing Monte Carlo simulation where the sign-problem is\nabsent. Moreover, in limiting cases where the exact ground state is known we\nshow that our ansatz is able to capture this behavior. Finally, we study a\nsign-problem affected regime by probing density-induced phase transitions."
    },
    {
        "anchor": "Lattice $(\u03a6^4)_4$ Effective Potential Giving Spontaneous Symmetry\n  Breaking and the Role of the Higgs Mass: We present a critical reappraisal of the available results on the broken\nphase of $\\lambda(\\Phi^4)_4$ theory, as obtained from rigorous formal analyses\nand from lattice calculations. All the existing evidence is compatible with\nSpontaneous Symmetry Breaking but dictates a trivially free shifted field that\nbecomes controlled by a quadratic hamiltonian in the continuum limit. As\nrecently pointed out, this implies that the simple one-loop effective potential\nshould become effectively exact. Moreover, the usual naive assumption that the\nHiggs mass-squared $m^2_h$ is proportional to its ``renormalized''\nself-coupling $\\lambda_R$ is not valid outside perturbation theory: the\nappropriate continuum limit has $m_h$ finite and vanishing $\\lambda_R$. A Monte\nCarlo lattice computation of the $\\lambda(\\Phi^4)_4$ effective potential, both\nin the single-component and in the O(2)-symmetric cases, is shown to agree very\nwell with the one-loop prediction. Moreover, its perturbative leading-log\nimprovement (based on the concept of $\\lambda_R$) fails to reproduce the Monte\nCarlo data. These results, while supporting in a new fashion the peculiar\n``triviality'' of the $\\lambda(\\Phi^4)_4$ theory, also imply that, outside\nperturbation theory, the magnitude of the Higgs mass does not give a measure of\nthe observable interactions in the scalar sector of the standard model.",
        "positive": "Evidence for quenched chiral logs: Using the pole shifting procedure of the modified quenched approximation\n(MQA) to cure the exceptional configuration problem, accurate hadron hadron\nspectrum calculations can be obtained at very light quark mass. Here we use the\nMQA to extend and improve our previous investigation of chiral logs in the pion\nmass. At beta=5.7 for Wilson fermion, we see clear evidence for quenched chiral\nlogarithms in the pion mass as a function of quark mass. The size of the\nobserved chiral log exponent delta is in good agreement with the value obtained\nfrom a direct calculation of the eta' hairpin diagram."
    },
    {
        "anchor": "The physics of eight flavours: We study Quantum Chromodynamics with eight flavours by use of lattice\nsimulations and present evidence that the theory still breaks chiral symmetry\nin the zero temperature, continuum limit. This confirms that the lower end of\nthe conformal window of QCD lies above Nf = 8.",
        "positive": "Nonperturbative Renormalization of Operators in Near-Conformal Systems\n  Using Gradient Flows: We propose a continuous real space renormalization group transformation based\non gradient flow, allowing for a numerical study of renormalization without the\nneed for costly ensemble matching. We apply our technique in a pilot study of\nSU$(3)$ gauge theory with $N_f = 12$ fermions in the fundamental\nrepresentation, finding the mass anomalous dimension to be $\\gamma_m =\n0.23(6)$, consistent with other perturbative and lattice estimates. We also\npresent the first lattice calculation of the nucleon anomalous dimension in\nthis theory, finding $\\gamma_N = 0.05(5)$."
    },
    {
        "anchor": "Nucleon structure functions from dynamical (2+1)-flavor domain wall\n  fermions: We report lattice-volume independence of low moments of nucleon structure\nfunctions from the coarse RIKEN-BNL-Columbia (RBC) and UKQCD joint dynamical\n(2+1)-flavor domain-wall fermions (DWF) ensembles at the lattice cut off of\n(a^{-1}\\sim1.7) GeV. The isovector quark momentum fraction, (< x >_{u-d}), and\nhelicity fraction, (< x >_{\\Delta u - \\Delta d}), both fully non-perturbatively\nrenormalized are studied on two spatial volumes of ((\\sim {\\rm 2.7 fm})^3) and\n((\\sim {\\rm 1.8 fm})^3). Their naturally renormalized ratio, (< x >_{u-d}/< x\n>_{\\Delta u - \\Delta d}), is not affected by any finite-size effect. It does\nnot depend strongly on light quark mass and does agree well with the\nexperiment. The respective absolute values, fully non-perturbatively\nrenormalized, do not show any finite-size effect either. They show trending\ntoward the respective experimental values at the lightest up- and down-quark\nmass. This trending down to the experimental values appears to be a real\nphysical effect driven by lighter quarks. The observations are in contrast to\nthe huge finite-size effect seen in the axial-current form factors.",
        "positive": "Non--perturbative tests of the fixed point action for SU(3) gauge theory: In this paper (the second of a series) we extend our calculation of a\nclassical fixed point action for lattice $SU(3)$ pure gauge theory to include\ngauge configurations with large fluctuations. The action is parameterized in\nterms of closed loops of link variables. We construct a few-parameter\napproximation to the classical FP action which is valid for short correlation\nlengths. We perform a scaling test of the action by computing the quantity $G =\nL \\sqrt{\\sigma(L)}$ where the string tension $\\sigma(L)$ is measured from the\ntorelon mass $\\mu = L \\sigma(L)$. We measure $G$ on lattices of fixed physical\nvolume and varying lattice spacing $a$ (which we define through the\ndeconfinement temperature). While the Wilson action shows scaling violations of\nabout ten per cent, the approximate fixed point action scales within the\nstatistical errors for $ 1/2 \\ge aT_c \\ge 1/6$. Similar behaviour is found for\nthe potential measured in a fixed physical volume."
    },
    {
        "anchor": "The Gluon Propagator: We discuss the current state of what is known non-perturbatively about the\ngluon propagator in QCD, with emphasis on the information coming from lattice\nsimulations. We review the specification of the lattice Landau gauge and the\nprocedure for calculating the gluon propagator on the lattice. We also discuss\nsome of the difficulties in non-perturbative calculations, especially Gribov\ncopy issues. We trace the evolution of lattice simulations over the past dozen\nyears, emphasizing how the improvement in computations has led not only to more\nprecise determinations of the propagator, but has allowed more detailed\ninformation about it to be extracted.",
        "positive": "Light hadron spectroscopy on the lattice with the non-perturbatively\n  improved Wilson action: We present results for the light meson masses and decay constants as obtained\nfrom calculations with the non-perturbatively improved (`Alpha') action and\noperators on a 24^3 \\times 64 lattice at beta = 6.2, in the quenched\napproximation. The analysis was performed in a way consistent with O(a)\nimprovement. We obtained: reasonable agreement with experiment for the\nhyperfine splitting; f_K=156(17) MeV, f_pi =139(22) MeV, f_K/f_pi = 1.13(4) ;\nf_{K*}=219(7) MeV, f_rho =199(15) MeV, f_phi =235(4) MeV; f_{K*}^{T}(2 GeV) =\n178(10) MeV, f_rho^{T}(2 GeV) =165(11) MeV, where f_V^{T} is the coupling of\nthe tensor current to the vector mesons; the chiral condensate\n<\\bar{q}q>^\\bar{MS} (2 GeV)= - (253 +/- 25 MeV)^3. Our results are compared to\nthose obtained with the unimproved Wilson action. We also verified that the\nfree-boson lattice dispersion relation describes our results very accurately\nfor a large range of momenta."
    },
    {
        "anchor": "Confinement Artifacts in the U(1) and SU(2) Compact Lattice Gauge\n  Theories: We identify the artifact that causes confinement at strong coupling in\ncompact U(1) lattice gauge theory and show that most of the string tension in\ncompact SU(2) lattice gauge theory is due to plaquettes of negative trace.",
        "positive": "The Z(2) gauge model revisited: as a possible testbed for the\n  confinement and chiral symmetry phase transition of SU(2) lattice gauge\n  theory: Adopting the cooling technique to smooth the discontinuous Z(2) lattice gauge\nfield, we found that on SU(2) gauge configurations obtained by this smoothing\nthere exists clear discontinuity of the topological property at almost the same\npoint as the confinement-deconfinement phase transition of the original Z(2)\ngauge theory. This observation suggests the possibility that Z(2) gauge model\nmight be a testbed for analyzing the relation between the confinement and the\nchiral phase transition in which the topological objects are believed to play\ncrucial roles."
    },
    {
        "anchor": "Identifying spin and parity of charmonia in flight with lattice QCD: The spectrum of charmonium resonances contains a number of unanticipated\nstates along with several conventional quark-model excitations. The hadrons of\ndifferent quantum numbers $J^P$ appear in a fairly narrow energy band, where\n$J^P$ refers to the spin-parity of a hadron at rest. This poses a challenge for\nLattice QCD studies of (coupled-channel) meson-meson scattering aimed at the\ndetermination of scattering amplitudes and resonance pole positions. A wealth\nof information for this purpose can be obtained from the lattice spectra in\nframes with nonzero total momentum. These are particularly dense since hadrons\nwith different $J^P$ contribute to any given lattice irreducible\nrepresentation. This is because $J^P$ is not a good quantum number in flight,\nand also because the continuum symmetry is reduced on the lattice. In this\npaper we address the assignment of the underlying continuum $J^P$ quantum\nnumbers to charmonia in flight using a $N_f = 2 + 1$ CLS ensemble. As a first\nstep, we apply the single-hadron approach, where only interpolating fields of\nquark-antiquark type are used. The approach follows techniques previously\napplied to the light meson spectrum by the Hadron Spectrum Collaboration. The\nresulting spectra of charmonia with assigned $J^P$ will provide valuable\ninformation for the parameterization of (resonant) amplitudes in future\ndeterminations of resonance properties with lattice QCD.",
        "positive": "Hadron Structure: This is a review of recent developments in hadron structure within the\nframework of Lattice QCD. The main focus is on recent achievements in the\nevaluation of nucleon quantities, such as the axial charge, electromagnetic\nform factors, the Dirac and Pauli radii, the quark momentum fraction and the\nspin content of the nucleon, in view of simulations at pion masses very close\nto their physical value. A discussion of the systematic uncertainties and the\ncomputation of the disconnected contributions using dynamical simulations is\nalso included. Results emerging the properties of particles other than the\nnucleon are summarized, highlighting selected hyperon and meson form factors."
    },
    {
        "anchor": "Quenched Chiral Perturbation Theory to one loop: We calculate the divergences of the generating functional of quenched Chiral\nPerturbation Theory at one loop, and renormalize the theory by an appropriate\ndefinition of the counterterms. We show that the quenched chiral logarithms can\nbe reabsorbed in the renormalization of the B_0 parameter which, at lowest\norder, is proportional to the vacuum expectation value of the scalar quark\ndensity. Finally, we calculate several quantities at one loop to analyze the\nmodifications induced by quenching in the finite part of the one-loop\ncorrections. We point out that some of the finite loop corrections may diverge\nin the chiral limit.",
        "positive": "Heavy meson masses and decay constants from relativistic heavy quarks in\n  full lattice QCD: We determine masses and decay constants of heavy-heavy and heavy-charm\npseudoscalar mesons as a function of heavy quark mass using a fully\nrelativistic formalism known as Highly Improved Staggered Quarks for the heavy\nquark. We are able to cover the region from the charm quark mass to the bottom\nquark mass using MILC ensembles with lattice spacing values from 0.15 fm down\nto 0.044 fm. We obtain f_{B_c} = 0.427(6) GeV; m_{B_c} = 6.285(10) GeV and\nf_{\\eta_b} = 0.667(6) GeV. Our value for f_{\\eta_b} is within a few percent of\nf_{\\Upsilon} confirming that spin effects are surprisingly small for heavyonium\ndecay constants. Our value for f_{B_c} is significantly lower than potential\nmodel values being used to estimate production rates at the LHC. We discuss the\nchanging physical heavy-quark mass dependence of decay constants from\nheavy-heavy through heavy-charm to heavy-strange mesons. A comparison between\nthe three different systems confirms that the B_c system behaves in some ways\nmore like a heavy-light system than a heavy-heavy one. Finally we summarise\ncurrent results on decay constants of gold-plated mesons."
    },
    {
        "anchor": "Twisted reduction in large N QCD with adjoint Wilson fermions: The twisted space-time reduced model of large $N$ QCD with various flavours\nof adjoint Wilson fermions is constructed applying the symmetric twist boundary\nconditions with flux $k$. The models with one and two flavours show distinctive\nbehaviours. For the two flavor case, the string tension, calculated at $N=289$,\napproaches zero as we decrease the quark mass in a way consistent with the\ntheory being governed by an infrared fixed point. In contrast, the string\ntension for the case of a single adjoint Wilson fermion remains finite as the\nquark mass decreases to zero, supporting that this is a confining theory.",
        "positive": "Diquark Representations for Singly Heavy Baryons with Light Staggered\n  Quarks: In the staggered fermion formulation of lattice QCD, we construct diquark\noperators which are to be embedded in singly heavy baryons. The group\ntheoretical connections between continuum and lattice staggered diquark\nrepresentations are established."
    },
    {
        "anchor": "Digital quantum simulation and Pseudoquantum Simulation of\n  $\\mathbb{Z}_2$ Gauge Higgs Model: We present a quantum algorithm for digital quantum simulation of the\n$\\mathbb{Z}_2$ gauge-Higgs model on a $3\\times 3$ lattice, which is based on\nTrotter decomposition, the quantum adiabatic algorithm and its circuit\nrealization. Then we perform a classical demonstration, dubbed a pseudoquantum\nsimulation, on a GPU simulator. We obtain useful results on this model, which\nsuggest the topological properties of the deconfined phase and help to clarify\nthe phase diagram. It is suggested that the tricitical point, where the\nsecond-order critical lines of deconfinement-confinement transition and of\ndeconfinement-Higgs transition meet, seems to be on the the first-order\ncritical line of confinement-Higgs transition, at a point other than the end of\nthis critical line.",
        "positive": "$G_2$-QCD: Spectroscopy and the phase diagram at zero temperature and\n  finite density: Due to the fermion sign problem, standard lattice Monte-Carlo method for QCD\nfail at small temperatures and high baryon densities. $G_2$-QCD, QCD with the\ngauge group $SU(3)$ replaced by the exceptional Lie group $G_2$, can be\nsimulated using lattice techniques at these densities, and can therefore\nprovide an illustration of the possible phase structure. Here we present a\nsystematic investigation of the ground-state hadronic spectrum using lattice\nsimulations for different quark masses in several hadronic sectors. We then\nshow that the different hadronic scales of Goldstone bosons, intermediate\nbosons, and baryons is reflected in the phase structure at finite density."
    },
    {
        "anchor": "The running coupling of the minimal sextet composite Higgs model: We compute the renormalized running coupling of SU(3) gauge theory coupled to\nN_f = 2 flavors of massless Dirac fermions in the 2-index-symmetric (sextet)\nrepresentation. This model is of particular interest as a minimal realization\nof the strongly interacting composite Higgs scenario. A recently proposed\nfinite volume gradient flow scheme is used. The calculations are performed at\nseveral lattice spacings with two different implementations of the gradient\nflow allowing for a controlled continuum extrapolation and particular attention\nis paid to estimating the systematic uncertainties. For small values of the\nrenormalized coupling our results for the beta-function agree with perturbation\ntheory. For moderate couplings we observe a downward deviation relative to the\n2-loop beta-function but in the coupling range where the continuum\nextrapolation is fully under control we do not observe an infrared fixed point.\nThe explored range includes the locations of the zero of the 3-loop and the\n4-loop beta-functions in the MSbar scheme. The absence of a non-trivial zero in\nthe beta-function in the explored range of the coupling is consistent with our\nearlier findings based on hadronic observables, the chiral condensate and the\nGMOR relation. The present work is the first to report continuum\nnon-perturbative results for the sextet model.",
        "positive": "M\u00f6bius domain-wall fermions on gradient-flowed dynamical HISQ\n  ensembles: We report on salient features of a mixed lattice QCD action using valence\nM\\\"{o}bius domain-wall fermions solved on the dynamical $N_f=2+1+1$ HISQ\nensembles generated by the MILC Collaboration. The approximate chiral symmetry\nproperties of the valence fermions are shown to be significantly improved by\nutilizing the gradient-flow scheme to first smear the HISQ configurations. The\ngreater numerical cost of the M\\\"{o}bius domain-wall inversions is mitigated by\nthe highly efficient QUDA library optimized for NVIDIA GPU accelerated compute\nnodes. We have created an interface to this optimized QUDA solver in Chroma. We\nprovide tuned parameters of the action and performance of QUDA using ensembles\nwith the lattice spacings $a \\simeq \\{0.15, 0.12, 0.09\\}$ fm and pion masses\n$m_\\pi \\simeq \\{310, 220,130\\}$ MeV. We have additionally generated two new\nensembles with $a\\sim0.12$ fm and $m_\\pi\\sim\\{400, 350\\}$ MeV. With a fixed\nflow-time of $t_{gf}=1$ in lattice units, the residual chiral symmetry breaking\nof the valence fermions is kept below 10\\% of the light quark mass on all\nensembles, $m_{res} \\lesssim 0.1\\times m_l$, with moderate values of the fifth\ndimension $L_5$ and a domain-wall height $M_5 \\leq 1.3$. As a benchmark\ncalculation, we perform a continuum, infinite volume, physical pion and kaon\nmass extrapolation of $F_{K^\\pm}/F_{\\pi^\\pm}$ and demonstrate our results are\nindependent of flow-time, and consistent with the FLAG determination of this\nquantity at the level of less than one standard deviation."
    },
    {
        "anchor": "Thermodynamics of Lattice QCD with 2 Quark Flavours: Chiral Symmetry and\n  Topology: We have studied the restoration of chiral symmetry in lattice QCD at the\nfinite temperature transition from hadronic matter to a quark-gluon plasma. By\nmeasuring the screening masses of flavour singlet and non-singlet meson\nexcitations, we have seen evidence that, although flavour chiral symmetry is\nrestored at this transition, flavour singlet (U(1)) axial symmetry is not. We\nconclude that this indicates that instantons continue to play an important role\nin the quark-gluon plasma phase.",
        "positive": "Electromagnetic form factors of the Delta baryon: We develop a methodology that enables us to extract accurately the\nelectromagnetic Delta form factors and their momentum dependence. We test our\napproach in the quenched approximation as a preparation for a study using\ndynamical fermions. Our calculation of the four form factors covers pion masses\nbetween about 410 MeV and 560 MeV on lattices with a size of 2.9 fm and a\nlattice spacing 0.09 fm. From the form factors we are able to obtain estimates\nof the magnetic moment and the charge radius of the Delta, which we compare to\nexisting experimental and theoretical results.Our non-zero result for the\nelectric quadrupole form factor signals a deformation of the Delta, pointing to\nan oblate charge distribution."
    },
    {
        "anchor": "Topological susceptibility of QCD with dynamical M\u00f6bius domain wall\n  fermions: We compute the topological susceptibility $\\chi_t$ of lattice QCD with $2+1$\ndynamical quark flavors described by the M\\\"obius domain wall fermion.\nViolation of chiral symmetry as measured by the residual mass is kept at\n$\\sim$1 MeV or smaller. We measure the fluctuation of the topological charge\ndensity in a `slab' sub-volume of the simulated lattice using the method\nproposed by Bietenholz {\\it et al.} The quark mass dependence of $\\chi_t$ is\nconsistent with the prediction of chiral perturbation theory, from which the\nchiral condensate is extracted as $\\Sigma^{\\overline{\\rm MS}} (\\mbox{2GeV}) =\n[274(13)(29)\\mbox{MeV}]^3$, where the first error is statistical and the second\none is systematic. Combining the results for the pion mass $M_\\pi$ and decay\nconstant $F_\\pi$, we obtain $\\chi_t = 0.229(03)(13)M_\\pi^2F_\\pi^2$ at the\nphysical point.",
        "positive": "Lattice QCD Study of $B$-meson Decay Constants from ETMC: We discuss a lattice QCD computation of the $B$-meson decay constants by the\nETM collaboration where suitable ratios allow to reach the bottom quark sector\nby combining simulations around the charm-quark mass with an exactly known\nstatic limit. The different steps involved in this ratio method are discussed\ntogether with an account of the assessment of various systematic effects. A\ncomparison of results from simulations with two and four flavour dynamical\nquarks is presented."
    },
    {
        "anchor": "Singlet vs Nonsinglet Perturbative Renormalization factors of Staggered\n  Fermion Bilinears: In this paper we present the perturbative computation of the difference\nbetween the renormalization factors of flavor singlet\n($\\sum_f\\bar\\psi_f\\Gamma\\psi_f$, $f$: flavor index) and nonsinglet\n($\\bar\\psi_{f_1} \\Gamma \\psi_{f_2}, f_1 \\neq f_2$) bilinear quark operators\n(where $\\Gamma =\n\\mathbb{1},\\,\\gamma_5,\\,\\gamma_{\\mu},\\,\\gamma_5\\,\\gamma_{\\mu},\\,\n\\gamma_5\\,\\sigma_{\\mu\\,\\nu}$) on the lattice. The computation is performed to\ntwo loops and to lowest order in the lattice spacing, using Symanzik improved\ngluons and staggered fermions with twice stout-smeared links. The stout\nsmearing procedure is also applied to the definition of bilinear operators. A\nsignificant part of this work is the development of a method for treating some\nnew peculiar divergent integrals stemming from the staggered formalism. Our\nresults can be combined with precise simulation results for the renormalization\nfactors of the nonsinglet operators, in order to obtain an estimate of the\nrenormalization factors for the singlet operators. The results have been\npublished in Physical Review D.",
        "positive": "Three-dimensional lattice U(1) gauge-Higgs model at low $m_H$: We study the non-compact version of the U(1) gauge-Higgs model in three\ndimensions for $m_H = 30 GeV.$ We found that, using this formulation, rather\nmodest lattices approach quite well the infinite volume behaviour.The phase\ntransition is first order, as expected for this Higgs mass. The latent heat (in\nunits of $T_{cr}^4$) is compatible with the predictions of the two-loop\neffective potential; it is an order of magnitude less than the corresponding\nSU(2) value. The transition temperature and $<\\varphi^* \\varphi>$ in units of\nthe critical temperature are also compatible with the perturbative results."
    },
    {
        "anchor": "Twisted mass fermions: neutral pion masses from disconnected\n  contributions: Twisted mass fermions allow light quarks to be explored but with the\nconsequence that there are mass splittings, such as between the neutral and\ncharged pion. Using a direct calculation of the connected neutral pion\ncorrelator and stochastic methods to evaluate the disconnected correlations, we\ndetermine the neutral pion mass. We explore the dependence on lattice spacing\nand quark mass in quenched QCD. For dynamical QCD, we determine the sign of the\nsplitting which is linked, via chiral PT, to the nature of the phase transition\nat small quark mass.",
        "positive": "Master-field simulations of O(a)-improved lattice QCD: Algorithms,\n  stability and exactness: In master-field simulations of lattice QCD, the expectation values of\ninterest are obtained from a single or at most a few representative gauge-field\nconfigurations on very large lattices. If the light quarks are included, the\ngeneration of these fields using standard techniques is however challenging in\nview of various algorithmic instabilities and precision issues. Ways to\novercome these problems are described here for the case of the O(a)-improved\nWilson formulation of lattice QCD and the viability of the proposed measures is\nthen checked in extensive simulations of the theory with 2+1 flavours of\nquarks."
    },
    {
        "anchor": "Few-body physics on a space-time lattice in the worldline approach: We formulate the physics of two species of non-relativistic hard-core bosons\nwith attractive or repulsive delta function interactions on a space-time\nlattice in the worldline approach. We show that worm algorithms can efficiently\nsample the worldline configurations in any fixed particle-number sector if the\nchemical potential is tuned carefully. Since fermions can be treated as\nhard-core bosons up to a permutation sign, we apply this approach to study\nnon-relativistic fermions. The fermion permutation sign is an observable in\nthis approach and can be used to extract energies in each particle-number\nsector. In one dimension, non-relativistic fermions can only permute across\nboundaries, and so our approach does not suffer from sign problems in many\ncases, unlike the auxiliary field method. Using our approach, we discover\nlimitations of the recently proposed complex Langevin calculations in one\nspatial dimension for some parameter regimes. In higher dimensions, our method\nsuffers from the usual fermion sign problem. Here we provide evidence that it\nmay be possible to alleviate this problem for few-body physics",
        "positive": "Gradient Flow: Perturbative and Non-Perturbative Renormalization: We review the gradient flow for gauge and fermion fields and its applications\nto lattice gauge theory computations. Using specific examples, we discuss the\ninterplay between perturbative and non-perturbative calculations in the context\nof renormalization with the gradient flow."
    },
    {
        "anchor": "(Lattice) Propagators and Extraction of Spectral Densities: In this proceeding, we explain a few steps for an alternative extraction of\nthe spectral density of a two-point function (propagator) based on a discrete\nset of data points. We present a so-called Tikhonov regularization of this\nparticular inverse problem. We test it on 2 cases: lattice 0++} glueball data\nand mock gluon data.",
        "positive": "Masses and decay constants of D(s)* and B(s)* mesons with Nf = 2 + 1 + 1\n  twisted mass fermions: We present a lattice calculation of the masses and decay constants of\n$D_{(s)}^*$ and $B_{(s)}^*$ mesons using the gauge configurations produced by\nthe European Twisted Mass Collaboration (ETMC) with $N_f = 2 + 1 + 1$ dynamical\nquarks at three values of the lattice spacing $a \\sim (0.06 - 0.09)$ fm. Pion\nmasses are simulated in the range $M_\\pi \\simeq (210 - 450)$ MeV, while the\nstrange and charm sea-quark masses are close to their physical values. We\ncompute the ratios of vector to pseudoscalar masses and decay constants for\nvarious values of the heavy-quark mass $m_h$ in the range $0.7\nm_c^{\\mathrm{phys}} \\lesssim m_h \\lesssim 3 m_c^{\\mathrm{phys}}$. In order to\nreach the physical b-quark mass, we exploit the Heavy Quark Effective Theory\nprediction that, in the static limit of infinite heavy-quark mass, the\nconsidered ratios are equal to one. At the physical point our results are:\n$M_{D^*} / M_{D} = 1.0769(79)$, $M_{D^*_{s}} / M_{D_{s}} = 1.0751(56)$, $\nf_{D^*} / f_{D} = 1.078(36),$ $f_{D^*_{s}} / f_{D_{s}} = 1.087(20)$, $M_{B^*} /\nM_{B} = 1.0078(15)$, $M_{B^*_{s}} / M_{B_{s}} = 1.0083(10)$, $f_{B^*} / f_{B} =\n0.958(22)$ and $f_{B^*_{s}} / f_{B_{s}} = 0.974(10)$. Combining them with the\nexperimental values of the pseudoscalar meson masses (used as input to fix the\nquark masses) and the values of the pseudoscalar decay constants calculated by\nETMC, we get: $M_{D^*} = 2013(14)~\\mathrm{MeV}$, $ M_{D_s^*} =\n2116(11)~\\mathrm{MeV}$, $f_{D^*} = 223.5(8.4)~\\mathrm{MeV}$, $f_{D_s^*} =\n268.8(6.6)~\\mathrm{MeV}$, $M_{B^*} = 5320.5(7.6)~\\mathrm{MeV}$, $M_{B_s^*} =\n5411.36(5.3)~\\mathrm{MeV}$, $f_{B^*} = 185.9(7.2)~\\mathrm{MeV}$ and $f_{B_s^*}\n= 223.1(5.4)~\\mathrm{MeV}$."
    },
    {
        "anchor": "Exploring the nature of chiral phase transition in two-flavor QCD using\n  extra heavy quarks: Chiral phase transition of two flavor QCD at finite quark masses is known to\nbe crossover except near the chiral limit, but it can turn to a first order\ntransition when adding many extra flavors. This property is used to explore the\nnature of the phase transition of massless two flavor QCD using lattice\nnumerical simulations. The extra heavy flavors being incorporated in the form\nof the hopping parameter expansion through the reweighting, the number of the\nextra flavors and their masses appear only in a single parameter, defined by\n$h$. We determine the critical value of the parameter, at which the first order\nand the crossover regions are separated, and examine its dependence on the two\nflavor mass. The lattice calculations are carried out at $N_t$=4, and show that\nthe critical value does not depend on the two flavor mass in the range we have\nstudied ($0.46 \\le m_\\pi/m_\\rho \\le 0.66$) and appears to remain finite and\npositive in the chiral limit, suggesting that the phase transition of massless\ntwo flavor QCD is of second order.",
        "positive": "The density of states approach to the sign problem: Approaches to the sign problem based on the density of states have been\nrecently revived by the introduction of the LLR algorithm, which allows us to\ncompute the density of states itself with exponential error reduction. In this\nwork, after a review of the generalities of the method, we show recent results\nfor the Bose gas in four dimensions, focussing on the identification of\npossible systematic errors and on methods of controlling the bias they can\nintroduce in the calculation."
    },
    {
        "anchor": "Lattice Coulomb propagators, effective energy and confinement: We show that in the lattice Hamiltonian limit all Coulomb gauge propagators\nare consistent with the Gribov-Zwanziger confinement mechanism, with an IR\nenhanced effective energy for quarks and gluons and a diverging ghost form\nfactor compatible with a dual-superconducting vacuum. Multiplicative\nrenormalizability is ensured for all static correlators, while for non-static\nones their energy dependence plays a crucial role in this respect. Moreover,\nfrom the Coulomb potential we can extract the Coulomb string tension \\sigma_C ~\n2 \\sigma.",
        "positive": "B decays to radially excited D: We discuss the possibility to measure in present experiments, especially\nLHCb, the non leptonic decay branching ratio $B \\to D' \\pi$, and emphasize\nphenomenological implications on $B \\to D' l \\nu$ semileptonic decay. We have\nestimated by lattice QCD the $D'$ decay constant $f_{D'}$ that parameterizes\nthe $D'$ emission contribution to the Class-III non leptonic decay $B^- \\to D^0\n\\pi^-$. In addition, we provide a new estimate of the decay constants\n$f_{D_{s,q}}$ which read $f_{D_{s}}=252(3)$ MeV and\n$f_{D_{s}}/f_{D}=1.23(1)(1)$."
    },
    {
        "anchor": "Nucleon and $N^* (1535)$ Distribution Amplitudes: The QCDSF collaboration has investigated the distribution amplitudes and\nwavefunction normalization constants of the nucleon and its parity partner, the\n$N^* (1535)$. We report on recent progress in the calculation of these\nquantities on configurations with two dynamical flavors of\n$\\mathcal{O}(a)$-improved Wilson fermions. New data at pion masses of\napproximately 270 MeV helps in significantly reducing errors in the\nextrapolation to the physical point.",
        "positive": "A simple construction of fermion measure term in U(1) chiral lattice\n  gauge theories with exact gauge invariance: In the gauge invariant formulation of U(1) chiral lattice gauge theories\nbased on the Ginsparg-Wilson relation, the gauge field dependence of the\nfermion measure is determined through the so-called measure term. We derive a\nclosed formula of the measure term on the finite volume lattice. The Wilson\nline degrees of freedom (torons) of the link field are treated separately to\ntake care of the global integrability. The local counter term is explicitly\nconstructed with the local current associated with the cohomologically trivial\npart of the gauge anomaly in a finite volume. The resulted formula is very\nclose to the known expression of the measure term in the infinite volume with a\nsingle parameter integration, and would be useful in practical implementations."
    },
    {
        "anchor": "Isospin splittings of meson and baryon masses from three-flavor lattice\n  QCD + QED: Lattice QCD simulations are now reaching a precision where isospin breaking\neffects become important. Previously, we have developed a program to\nsystematically investigate the pattern of flavor symmetry beaking within QCD\nand successfully applied it to meson and baryon masses involving up, down and\nstrange quarks. In this Letter we extend the calculations to QCD + QED and\npresent our first results on isospin splittings in the pseudoscalar meson and\nbaryon octets. In particular, we obtain the nucleon mass difference of\n$M_n-M_p=1.35(18)(8)\\,\\mbox{MeV}$ and the electromagnetic contribution to the\npion splitting $M_{\\pi^+}-M_{\\pi^0}=4.60(20)\\,\\mbox{MeV}$. Further we report\nfirst determination of the separation between strong and electromagnetic\ncontributions in the $\\bar{MS}$ scheme.",
        "positive": "Finite-volume and partial quenching effects in the magnetic\n  polarizability of the neutron: There has been much progress in the experimental measurement of the electric\nand magnetic polarizabilities of the nucleon. Similarly, lattice QCD\nsimulations have recently produced dynamical QCD results for the magnetic\npolarizability of the neutron approaching the chiral regime. In order to\ncompare the lattice simulations with experiment, calculation of partial\nquenching and finite-volume effects is required prior to an extrapolation in\nquark mass to the physical point. These dependencies are described using chiral\neffective field theory. Corrections to the partial quenching effects associated\nwith the sea-quark-loop electric charges are estimated by modelling corrections\nto the pion cloud. These are compared to the uncorrected lattice results. In\naddition, the behaviour of the finite-volume corrections as a function of pion\nmass is explored. Box sizes of approximately 7 fm are required to achieve a\nresult within 5% of the infinite-volume result at the physical pion mass. A\nvariety of extrapolations are shown at different box sizes, providing a\nbenchmark to guide future lattice QCD calculations of the magnetic\npolarizabilities. A relatively precise value for the physical magnetic\npolarizability of the neutron is presented, beta_n = 1.93(11)stat(8)sys x 10^-4\nfm^3, which is in agreement with current experimental results."
    },
    {
        "anchor": "Density of States FFA analysis of SU(3) lattice gauge theory at a finite\n  density of color sources: We present a Density of States calculation with the Functional Fit Approach\n(DoS FFA) in SU(3) lattice gauge theory with a finite density of static color\nsources. The DoS FFA uses a parameterized density of states and determines the\nparameters of the density by fitting data from restricted Monte Carlo\nsimulations with an analytically known function. We discuss the implementation\nof DoS FFA and the results for a qualitative picture of the phase diagram in a\nmodel which is a further step towards implementing DoS FFA in full QCD. We\ndetermine the curvature $\\kappa$ in the $\\mu$-$T$ phase diagram and find a\nvalue close to the results published for full QCD.",
        "positive": "Stable and quasi-stable confining SU(N) strings in D=2+1: We investigate the low-lying spectrum of closed confining flux-tubes that\nwind around a spatial torus in D=2+1 and carry flux in different\nrepresentations of SU(N). We focus on our most recent calculations for N=6 and\n{\\beta}=171, where the calculated low-energy physics is very close to the\ncontinuum and large-N limits. We investigate the adjoint, 84, 120, k = 2A, 2S\nand k = 3A, 3M, 3S representations and show that the corresponding flux-tubes\ndo exist. Similarly to the results for the fundamental representation, the\nground state of a flux-tube with momentum along its axis appears to be well\ndescribed by Nambu-Goto all the way down to very short tubes. In contrast,\nexcited states have much larger deviations from Nambu-Goto. We discuss whether\nthese states are non-string-like and associated with excitations of massive\nflux-tube modes."
    },
    {
        "anchor": "On Witten's global anomaly for higher SU(2) representations: The spectral flow of the overlap operator is computed numerically along a\npath connecting two gauge fields which differ by a topologically non-trivial\ngauge transformation. The calculation is performed for SU(2) in the 3/2 and 5/2\nrepresentation. An even-odd pattern for the spectral flow as predicted by\nWitten is verified. The results are, however, more complicated than naively\nexpected.",
        "positive": "Perturbation theory vs. simulation for tadpole improvement factors in\n  pure gauge theories: We calculate the mean link in Landau gauge for Wilson and improved SU(3)\nanisotropic gauge actions, using two loop perturbation theory and Monte Carlo\nsimulation employing an accelerated Langevin algorithm. Twisted boundary\nconditions are employed, with a twist in all four lattice directions\nconsiderably improving the (Fourier accelerated) convergence to an improved\nlattice Landau gauge. Two loop perturbation theory is seen to predict the mean\nlink extremely well even into the region of commonly simulated gauge couplings\nand so can be used remove the need for numerical tuning of self-consistent\ntadpole improvement factors. A three loop perturbative coefficient is inferred\nfrom the simulations and is found to be small. We show that finite size effects\nare small and argue likewise for (lattice) Gribov copies and double Dirac\nsheets."
    },
    {
        "anchor": "Properties of light pseudoscalars from lattice QCD with HISQ ensembles: We fit lattice-QCD data for light-pseudoscalar masses and decay constants,\nfrom HISQ configurations generated by MILC, to SU(3) staggered chiral\nperturbation theory. At present such fits have rather high values of\nchi^2/d.o.f., possibly due to the lack of ensembles with lighter-than-physical\nsea strange-quark masses. We propose solutions to this problem for future work.\nWe also perform simple linear interpolations near the physical point on two\nensembles with different lattice spacings, and obtain the preliminary result\n(f_K / f_pi)^phys = 1.1872(41) in the continuum limit.",
        "positive": "Nucleon spin structure from lattice QCD: In this lattice QCD study we evaluate the nucleon spin decomposition to\nquarks and gluons contributions. We employ one gauge ensemble of maximally\ntwisted mass fermions with two degenerate light quarks tuned to approximately\nreproduce the physical pion mass. We find that both spin sum and momentum sum\nare satisfied within the current statistical and systematic accuracy."
    },
    {
        "anchor": "Existence and Non-Existence of Doubly Heavy Tetraquark Bound States: In this work we investigate the existence of bound states for doubly heavy\ntetraquark systems $ \\bar{Q}\\bar{Q}'qq' $ in a full lattice-QCD computation,\nwhere heavy bottom quarks are treated in the framework of non-relativistic QCD.\nWe focus on three systems with quark content $ \\bar{b}\\bar{b}ud $, $\n\\bar{b}\\bar{b}us $ and $ \\bar{b}\\bar{c}ud $. We show evidence for the existence\nof $ \\bar{b}\\bar{b}ud $ and $ \\bar{b}\\bar{b}us $ bound states, while no binding\nappears to be present for $ \\bar{b}\\bar{c}ud $. For the bound four-quark states\nwe also discuss the importance of various creation operators and give an\nestimate of the meson-meson and diquark-antidiquark percentages.",
        "positive": "An iterative method to compute the overlap Dirac operator at nonzero\n  chemical potential: The overlap Dirac operator at nonzero quark chemical potential involves the\ncomputation of the sign function of a non-Hermitian matrix. In this talk we\npresent an iterative method, first proposed by us in Ref. [1], which allows for\nan efficient computation of the operator, even on large lattices. The starting\npoint is a Krylov subspace approximation, based on the Arnoldi algorithm, for\nthe evaluation of a generic matrix function. The efficiency of this method is\nspoiled when the matrix has eigenvalues close to a function discontinuity. To\ncure this, a small number of critical eigenvectors are added to the Krylov\nsubspace, and two different deflation schemes are proposed in this augmented\nsubspace. The ensuing method is then applied to the sign function of the\noverlap Dirac operator, for two different lattice sizes. The sign function has\na discontinuity along the imaginary axis, and the numerical results show how\ndeflation dramatically improves the efficiency of the method."
    },
    {
        "anchor": "(1+1)-d U(1) Quantum link models from effective Hamiltonians of dipolar\n  molecules: We study the promising idea of using dipolar molecular systems as analog\nquantum simulators for quantum link models, which are discrete versions of\nlattice gauge theories. In a quantum link model the link variables have a\nfinite number of degrees of freedom and discrete values. We construct the\neffective Hamiltonian of a system of dipolar molecules with electric\ndipole-dipole interactions, where we use the tunable parameters of the system\nto match it to the target Hamiltonian describing a U(1) quantum link model in\n1+1 dimensions.",
        "positive": "Towards charm physics with stabilised Wilson fermions: We report on a first study towards the use of stabilised Wilson fermions in\nheavy flavour physics. In particular, we are interested in fixing the charm\nquark mass via various physical observables and to inspect cut-off effects\narising from different choices. This is done on large-volume OpenLat ensembles\nwith periodic boundary conditions. Two different ways of fixing the charm quark\nmass are explored, namely using the mass of the $D$- and $\\eta_{\\rm c}$-meson\nas physical inputs. We furthermore give an update on our determination of the\nnon-singlet axial current improvement coefficient $c_{\\rm A}$."
    },
    {
        "anchor": "Precision lattice QCD calculations and predictions of fundamental\n  physics in heavy quark systems: I describe the recent success in performing accurate calculations of the\neffects of the strong force on particles containing bottom and charm quarks.\nSince quarks are never seen in isolation, and so cannot be studied directly,\nnumerical simulations are key to understanding the properties of these\nparticles and extracting information about the quarks. The results have direct\nimpact on the worldwide experimental programme that is aiming to determine the\nparameters of the Standard Model of particle physics precisely and thereby\nuncover or constrain the possibilities for physics beyond the Standard Model.\nThe numerical simulation of the strong force is a huge computational task and\nthe recent success is the result of international collaboration in developing\ntechniques that are fast enough to do the calculations on powerful\nsupercomputers.",
        "positive": "Self-learning Monte-Carlo for non-abelian gauge theory with dynamical\n  fermions: In this paper, we develop the self-learning Monte-Carlo (SLMC) algorithm for\nnon-abelian gauge theory with dynamical fermions in four dimensions to resolve\nthe autocorrelation problem in lattice QCD. We perform simulations with the\ndynamical staggered fermions and plaquette gauge action by both in HMC and SLMC\nfor zero and finite temperature to examine the validity of SLMC. We confirm\nthat SLMC can reduce autocorrelation time in non-abelian gauge theory and\nreproduces results from HMC. For finite temperature runs, we confirm that SLMC\nreproduces correct results with HMC, including higher-order moments of the\nPolyakov loop and the chiral condensate. Besides, our finite temperature\ncalculations indicate that four flavor QC${}_2$D with $\\hat{m} = 0.5$ is likely\nin the crossover regime in the Colombia plot."
    },
    {
        "anchor": "Thermodynamics and Finite size scaling in Scalar Field Theory: In this work we consider the 1-component real scalar $\\phi^4$ theory in 4\nspace-time dimensions on the lattice and investigate the finite size scaling of\nthermodynamic quantities to study whether the thermodynamic limit is attained.\nThe results are obtained for the symmetric phase of the theory.",
        "positive": "Progress and prospects of lattice supersymmetry: Supersymmetry plays prominent roles in the study of quantum field theory and\nin many proposals for potential new physics beyond the standard model, while\nlattice field theory provides a non-perturbative regularization suitable for\nstrongly interacting systems. Lattice investigations of supersymmetric field\ntheories are currently making significant progress, though many challenges\nremain to be overcome. In this brief overview I discuss particularly notable\nprogress in three areas: supersymmetric Yang--Mills (SYM) theories in fewer\nthan four dimensions, as well as both minimal N=1 SYM and maximal N=4 SYM in\nfour dimensions. I also highlight super-QCD and sign problems as prominent\nchallenges that will be important to address in future work."
    },
    {
        "anchor": "Two dimensional fermions in three dimensional YM: Dirac fermions in the fundamental representation of SU(N) live on the surface\nof a cylinder embedded in $R^3$ and interact with a three dimensional SU(N)\nYang Mills vector potential preserving a global chiral symmetry at finite $N$.\nAs the circumference of the cylinder is varied from small to large, the chiral\nsymmetry gets spontaneously broken in the infinite $N$ limit at a typical bulk\nscale. Replacing three dimensional YM by four dimensional YM introduces\nnon-trivial renormalization effects.",
        "positive": "Effects of Dense Quark Matter on Gluon Propagators in Lattice QC$_2$D: The transverse and longitudinal gluon propagators in the Landau gauge are\nstudied in the two-color lattice QCD at nonzero quark chemical potential\n$\\mu_q$. Parameterization of the momentum dependence of the propagators is\nprovided for all values of chemical potential under study. We find that the\nlongitudinal propagator is infrared suppressed at nonzero $\\mu_q$ with\nsuppression increasing with increasing $\\mu_q$. The transverse propagator\ndependence on $\\mu_q$ was found to be opposite: it is enhanced at large\n$\\mu_q$. It is found, respectively, that the electric screening mass is\nincreasing while the magnetic screening mass is decreasing with increasing\n$\\mu_q$. Nice agreement between the electric screening mass computed from the\nlongitudinal propagator and the Debye mass computed earlier from the singlet\nstatic quark-antiquark potential was found. We discuss how the dependence of\nthe propagators on the chemical potential correlates with the respective\ndependence of the string tension. Additionally, we consider the difference\nbetween two propagators as a function of the momentum and make interesting\nobservations."
    },
    {
        "anchor": "Comparison of Improved Perturbative Methods: In many cases of interest, the perturbative series based on conventional\nFeynman diagrams have a zero radius of convergence. Series with a finite radius\nof convergence can be obtained by either introducing a large field cutoff or by\nreplacing the exponential of the perturbation by a sequence of approximants as\nrecently proposed by Pollet, Prokof'ev, and Svistunov. We compare these two\nmethods for integrals and quantum mechanical problems. The two methods perform\nwell in complementary regime (strong coupling for the large field cutoff and\nintermediate coupling for the other method). We briefly discuss potential\napplications for lattice gauge theory with compact groups (which have a\nbuild-in large field cutoff).",
        "positive": "Which Higgs-Yukawa systems can possess non-trivial fixed points: We argue that non-trivial fixed points bordering on the paramagnetic and\nferromagnetic phases are most likely to exist in the Higgs-Yukawa systems that\nhave a connected domain with the paramagnetic phase and no ferrimagnetic phase.\nWe find three examples of such systems; among them is the U(1) system with\nnaive fermions."
    },
    {
        "anchor": "PDFs in small boxes: PDFs can be studied directly using lattice QCD by evaluating matrix elements\nof non-local operators. A number of groups are pursuing numerical calculations\nand investigating possible systematic uncertainties. One systematic that has\nreceived less attention is the effect of calculating in a finite spacetime\nvolume. Here we present first attempts to assess the role of the finite volume\nfor spatially non-local operators. We find that these matrix elements may\nsuffer from large finite-volume artifacts and more careful investigation is\nneeded.",
        "positive": "3+1D $\u03b8$-Term on the Lattice from the Hamiltonian Perspective: Quantum and tensor network simulations have emerged as prominent sign-problem\nfree approaches to lattice gauge theories. Unlike conventional Markov chain\nMonte Carlo methods, they are based on the Hamiltonian formulation. In this\ntalk, we fill a gap in the literature and present the first derivation of the\nHamiltonian 3+1D $\\theta$-term -- which is an important sign-problem afflicted\nterm -- for Abelian and non-Abelian lattice gauge theories. Furthermore, we\nperform exact diagonalization for a 3+1D U(1) lattice gauge theory including\nthe $\\theta$-term on a unit periodic cube. Our numerical results reveal a novel\nphase transition at fixed values of $\\theta$ in the strong-coupling regime. The\ntransition is evidenced by an avoided level crossing in the ground state\nenergy, as well as sudden changes in the plaquette expectation value, the\nelectric energy density, and the topological charge density. Extensions of our\nwork to larger lattices can be readily performed using state-of-the-art tensor\nnetwork simulations. Moreover, our work provides a concrete starting point for\nan eventual quantum simulation of the $\\theta$-dependent phase structure and\ndynamics of lattice gauge theories in 3+1D. This talk is mainly based on [1].\nWe expand beyond [1] by including a derivation of the (non-)Abelian\nfixed-length Higgs term in the Hamiltonian formulation for future studies of\n(non-)Abelian-Higgs models with a $\\theta$-term."
    },
    {
        "anchor": "QCD phase transition with two flavors of Wilson quarks using a RG\n  improved action: The finite temperature QCD phase transition is studied on the lattice with\ndegenerate two flavors of Wilson quarks. Motivated by reported strange\nbehaviors with the standard action on lattices with the temporal extention\n$N_t=4$ and 6, a renormalization group improved gauge action is applied. On an\n$N_t=4$ lattice, the strange behaviors observed with the standard action are\nremoved with our improved action. The finite temperature transition is\ncontinuous in the chiral limit and it becomes quite smooth in all observables\nwe studied when we increase the quark mass by increasing $\\beta$ along the\ncrossover line.",
        "positive": "$B_c$ and $\u03a5$ Spectra from Lattice NRQCD - Results at $\u03b2$ =\n  5.7: We update our results for the heavy-heavy spectrum at $\\beta$ = 5.7, using\nNRQCD. This includes a scaling comparison with the $\\Upsilon$ spectrum at\n$\\beta$ = 6.0 and first lattice predictions for the $B_c$ spectrum."
    },
    {
        "anchor": "Sigma term and strangeness content of octet baryons: By using lattice QCD computations we determine the sigma terms and\nstrangeness content of all octet baryons by means of an application of the\nHellmann-Feynman theorem. In addition to polynomial and rational expressions\nfor the quark mass dependence of octet members, we use SU(3) covariant baryon\nchiral perturbation theory to perform the extrapolation to the physical up and\ndown quark masses. Our N_f=2+1 lattice ensembles include pion masses down to\nabout 190 MeV in large volumes (M_\\pi L > 4), and three values of the lattice\nspacing. Our main results are the nucleon sigma term \\sigma_{\\pi N} =\n39(4)(^{+18}_{-7}) and the strangeness content y_{N} = 0.20(7)(^{+13}_{-17}).\nUnder the assumption of validity of covariant baryon \\chi PT in our range of\nmasses one finds y_{N} = 0.276(77)(^{+90}_{-62}).",
        "positive": "Lattice QCD analysis for relation between quark confinement and chiral\n  symmetry breaking: The Polyakov loop and the Dirac modes are connected via a simple analytical\nrelation on the temporally odd-number lattice, where the temporal lattice size\nis odd with the normal (nontwisted) periodic boundary condition. Using this\nrelation, we investigate the relation between quark confinement and chiral\nsymmetry breaking in QCD. In this paper, we discuss the properties of this\nanalytical relation and numerically investigate each Dirac-mode contribution to\nthe Polyakov loop in both confinement and deconfinement phases at the quenched\nlevel. This relation indicates that low-lying Dirac modes have little\ncontribution to the Polyakov loop, and we numerically confirmed this fact. From\nour analysis, it is suggested that there is no direct one-to-one corresponding\nbetween quark confinement and chiral symmetry breaking in QCD. Also, in the\nconfinement phase, we numerically find that there is a new \"positive/negative\nsymmetry\" in the Dirac-mode matrix elements of link-variable operator which\nappear in the relation and the Polyakov loop becomes zero because of this\nsymmetry. In the deconfinement phase, this symmetry is broken and the Polyakov\nloop is non-zero."
    },
    {
        "anchor": "Background field technique and renormalization in lattice gauge theory: Lattice gauge theory with a background gauge field is shown to be\nrenormalizable to all orders of perturbation theory. No additional counterterms\nare required besides those already needed in the absence of the background\nfield. The argument closely follows the treatment given earlier for the case of\ndimensional regularization by Kluberg-Stern and Zuber. It is based on the BRS,\nbackground gauge and shift symmetries of the lattice functional integral.",
        "positive": "SU(3) Quantum Spin Ladders as a Regularization of the CP(2) Model at\n  Non-Zero Density: From Classical to Quantum Simulation: Quantum simulations would be highly desirable in order to investigate the\nfinite density physics of QCD. $(1+1)$-d $\\mathbb{C}P(N-1)$ quantum field\ntheories are toy models that share many important features of QCD: they are\nasymptotically free, have a non-perturbatively generated massgap, as well as\n$\\theta$-vacua. $SU(N)$ quantum spin ladders provide an unconventional\nregularization of $\\mathbb{C}P(N-1)$ models that is well-suited for quantum\nsimulation with ultracold alkaline-earth atoms in an optical lattice. In order\nto validate future quantum simulation experiments of $\\mathbb{C}P(2)$ models at\nfinite density, here we use quantum Monte Carlo simulations on classical\ncomputers to investigate $SU(3)$ quantum spin ladders at non-zero chemical\npotential. This reveals a rich phase structure, with single- or double-species\nBose-Einstein \"condensates\", with or without ferromagnetic order."
    },
    {
        "anchor": "Redesigning Lattice QCD: There has been major progress in recent years in the development of improved\ndiscretizations of the QCD action, current operators, etc for use in numerical\nsimulations that employ very coarse lattices. These lectures review the field\ntheoretic techniques used to design these discretizations, techniques for\ntesting and tuning the new formalisms that result, and recent simulation\nresults employing these formalisms.",
        "positive": "A Multicanonical Algorithm and the Surface Free Energy in SU(3) Pure\n  Gauge Theory: We present a multicanonical algorithm for the SU(3) pure gauge theory at the\ndeconfinement phase transition. We measure the tunneling times for lattices of\nsize L^3x2 for L=8,10, and 12. In contrast to the canonical algorithm the\ntunneling time increases only moderately with L. Finally, we determine the\ninterfacial free energy applying the multicanonical algorithm."
    },
    {
        "anchor": "Eguchi-Kawai reduction with one flavor of adjoint Moebius fermion: We study the single site lattice gauge theory of SU(N) coupled to one Dirac\nflavor of fermion in the adjoint representation. We utilize M\\\"obius fermions\nfor this study, and accelerate the calculation with graphics processing units\n(GPUs). Our Monte Carlo simulations indicate that for sufficiently large\ninverse 't Hooft coupling b = 1/g^2 N, and for N \\leq 10 the distribution of\ntraced Polyakov loops has \"fingers\" that extend from the origin. However, in\nthe massless case the distribution of eigenvalues of the untraced Polyakov loop\nbecomes uniform at large N, indicating preservation of center symmetry in the\nthermodynamic limit. By contrast, for a large mass and large b, the\ndistribution is highly nonuniform in the same limit, indicating spontaneous\ncenter symmetry breaking. These conclusions are confirmed by comparing to the\nquenched case, as well as by examining another observable based on the average\nvalue of the modulus of the traced Polyakov loop. The result of this\ninvestigation is that with massless adjoint fermions center symmetry is\nstabilized and the Eguchi-Kawai reduction should be successful; this is in\nagreement with most other studies.",
        "positive": "Schr\"odinger functional at negative flavour number: The scaling of the Schr\"odinger functional coupling is studied numerically\nand perturbatively for an SU(3) lattice gauge field coupled to an O(a) improved\nbosonic spinor field. This corresponds to QCD with minus two light flavours and\nis used as a numerically less costly test case for real QCD. A suitable\nalgorithm is developed, and the influence of the matter fields on the continuum\nlimit and the lattice artefacts are studied in detail."
    },
    {
        "anchor": "The Vortex-Finding Property of Maximal Center (and Other) Gauges: We argue that the ``vortex-finding'' property of maximal center gauge, i.e.\nthe ability of this gauge to locate center vortices inserted by hand on any\ngiven lattice, is the key to its success in extracting the vortex content of\nthermalized lattice configurations. We explain how this property comes about,\nand why it is expected not only in maximal center gauge, but also in an\ninfinite class of gauge conditions based on adjoint-representation link\nvariables. In principle, the vortex-finding property can be foiled by Gribov\ncopies. This fact is relevant to a gauge-fixing procedure devised by Kovacs and\nTomboulis, where we show that the loss of center dominance, found in their\nprocedure, is explained by a corresponding loss of the vortex-finding property.\nThe association of center dominance with the vortex-finding property is\ndemonstrated numerically in a number of other gauges.",
        "positive": "The QCD Critical Point : marching towards continuum: We present results of our simulations of QCD with two light dynamical quarks\non a 32^3 X 8 lattice at a current quark mass tuned to have the Goldstone pion\nmass of about 230 MeV. Employing the Taylor expansion method we proposed\nearlier, we estimate the radius of convergence of the series for the baryonic\nsusceptibility by using terms up to eighth order. Together with our earlier\nresults, corresponding to the same physical parameters but on coarser lattices\nat respectively 1.33 times and twice the lattice cut-off (a), we were able to\nattempt a march towards the continuum limit."
    },
    {
        "anchor": "Electric polarizability of neutral hadrons from dynamical lattice QCD\n  ensembles: We present a valence calculation of the electric polarizability of the\nneutron, neutral pion, and neutral kaon on two dynamically generated\nnHYP-clover ensembles. The pion masses for these ensembles are 227(2) MeV and\n306(1) MeV, which are the lowest ones used in polarizability studies. This is\npart of a program geared towards determining these parameters at the physical\npoint. We carry out a high statistics calculation that allows us to: (1)\nperform an extrapolation of the kaon polarizability to the physical point; we\nfind $\\alpha_K =0.269(43)\\times10^{-4}$fm$^{3}$, (2) quantitatively compare our\nneutron polarizability results with predictions from $\\chi$PT, and (3) analyze\nthe dependence on both the valence and sea quark masses. The kaon\npolarizability varies slowly with the light quark mass and the extrapolation\ncan be done with high confidence.",
        "positive": "Valence quarks in the QCD plasma: quark number susceptibilities and\n  screening: We have investigated the quark sector of quenched QCD for 1.5\\le T/Tc\\le3 in\nthe continuum limit, using two different lattice discretisations of quarks and\nextrapolating from lattice spacings between 1/4T and 1/14T. At these\ntemperatures, the flavour off-diagonal susceptibility, chi_{ud}/T^2, is\ncompatible with zero at each lattice spacing, and hence also in the continuum\nlimit. In the continuum limit, the light quark susceptibilities are about 10%\nless than the ideal gas results even at the highest T, in agreement with hard\nthermal loop predictions but marginally below a resummed perturbative\ncomputation. For the mass range appropriate to the strange quark, the flavour\ndiagonal susceptibility is significantly smaller. Our estimate of the\nWroblewski parameter is compatible with observations at RHIC and SPS. The\ncontinuum limit of screening masses in all (local) quark-bilinears is very\nclose to the ideal gas results."
    },
    {
        "anchor": "Lattice QCD study of $g_A^{N^*N^*}$ with two flavors of dynamical quarks: We report the first lattice QCD result of the axial charge of N(1535),\n$g_A^{N^*N^*}$. The measurement is performed with two flavors of dynamical\nquarks employing the renormalization-group improved gauge action at\n$\\beta$=1.95 and the mean-field improved clover quark action with the hopping\nparameters, $\\kappa$=0.1375, 0.1390 and 0.1400. In order to avoid the signal\ncontaminations by N(1650) lying just 100 MeV above N(1535), we construct\n2$\\times$2 correlation matrices and diagonalize them so that clear signal\nseparation can be found. The wraparound contributions in the correlator, which\ncan be another source of signal contamination, are eliminated by imposing the\nDirichlet boundary condition in the temporal direction. We find that the axial\ncharge of N(1535) takes small values as $g_A^{N^*N^*}\\sim 0.2$, independent of\nquark masses, in the pion-mass range of 0.7 to 1.1 GeV.",
        "positive": "Temperature Dependence of Extended and Fractional SU(3) Monopole\n  Currents: We examine in pure SU(3) the dependence of extended monopole current k and\ncross-species extended monopole current k^{cross} on temperature t, monopole\nsize L, and fractional monopole charge 1/q. We find that features of both k and\nk^{cross} are sensitive to t for a range of L and q. In particular, the\nspatial-temporal asymmetry ratios of both k and k^{cross} are sensitive over a\nrange of L and q to the SU(3) deconfinement transition. The motivation for\nstudying cross, extended, and fractional monopoles in SU(3) is given."
    },
    {
        "anchor": "The Monte Carlo method in quantum field theory: This series of six lectures is an introduction to using the Monte Carlo\nmethod to carry out nonperturbative studies in quantum field theories. Path\nintegrals in quantum field theory are reviewed, and their evaluation by the\nMonte Carlo method with Markov-chain based importance sampling is presented.\nProperties of Markov chains are discussed in detail and several proofs are\npresented, culminating in the fundamental limit theorem for irreducible Markov\nchains. The example of a real scalar field theory is used to illustrate the\nMetropolis-Hastings method and to demonstrate the effectiveness of an\naction-preserving (microcanonical) local updating algorithm in reducing\nautocorrelations. The goal of these lectures is to provide the beginner with\nthe basic skills needed to start carrying out Monte Carlo studies in quantum\nfield theories, as well as to present the underlying theoretical foundations of\nthe method.",
        "positive": "Polyakov loop correlators and cyclic Wilson loop from lattice QCD: We discuss color screening in 2+1 flavor QCD in terms of free energies of a\nstatic quark-antiquark pair. Thermal modifications of long distance\ncorrelations in quark-antiquark systems are studied in terms of static meson\ncorrelators. We calculate the Polyakov loop correlator, the color-singlet\nWilson line correlator in Coulomb gauge and the cyclic Wilson loop on lattices\nusing the HISQ/Tree action and almost physical quark mases with $N_\\tau= 4, 6,\n8, 10, 12$. We present results in the continuum limit for temperatures up to $T\n\\lesssim 650$ MeV and discuss the linear divergence of the cyclic Wilson loop."
    },
    {
        "anchor": "Algorithms for Domain Wall Fermions: We discuss algorithms for domain wall fermions focussing on accelerating\nHybrid Monte Carlo sampling of gauge configurations. Firstly a new multigrid\nalgorithm for domain wall solvers and secondly a domain decomposed hybrid monte\ncarlo approach applied to large subvolumes and optimised for GPU accelerated\nnodes. We propose a formulation of DD-RHMC that is suitable for the simulation\nof odd numbers of fermions.",
        "positive": "Numerical Study of Periodic Instanton Configurations in Two-dimensional\n  Abelian Higgs Theory: Numerical minimization of the Euclidean action of the two-dimensional Abelian\nHiggs model is used to construct periodic instantons, the euclidean field\nconfigurations with two turning points describing transitions between the\nvicinities of topologically distinct vacua. Periodic instantons are found at\nany energy ( up to the sphaleron energy $E_{sph}$ ) and for wide range of\nparameters of the theory. We obtain the dependence of the action and the energy\nof periodic instanton on its period; these quantities directly determine the\nprobability of certain multiparticle scattering events."
    },
    {
        "anchor": "Charm sea effects on charmonium decay constants and heavy meson masses: We estimate the effects on the decay constants of charmonium and on heavy\nmeson masses due to the charm quark in the sea. Our goal is to understand\nwhether for these quantities $N_f=2+1$ lattice QCD simulations provide results\nthat can be compared with experiments or whether $N_f=2+1+1$ QCD including the\ncharm quark in the sea needs to be simulated. We consider two theories, $N_f=0$\nQCD and QCD with $N_f=2$ charm quarks in the sea. The charm sea effects (due to\ntwo charm quarks) are estimated comparing the results obtained in these two\ntheories, after matching them and taking the continuum limit. The absence of\nlight quarks allows us to simulate the $N_f=2$ theory at lattice spacings down\nto $0.023$ fm that are crucial for reliable continuum extrapolations. We find\nthat sea charm quark effects are below $1\\%$ for the decay constants of\ncharmonium. Our results show that decoupling of charm works well up to energies\nof about $500$ MeV. We also compute the derivatives of the decay constants and\nmeson masses with respect to the charm mass. For these quantities we again do\nnot see a significant dynamical charm quark effect, albeit with a lower\nprecision. For mesons made of a charm quark and a heavy antiquark, whose mass\nis twice that of the charm quark, sea effects are only about $0.1\\%$ in the\nratio of vector to pseudoscalar masses.",
        "positive": "Scaling behavior of chiral phase transition in two-flavor QCD with\n  improved Wilson quarks at finite density: We study scaling behavior of a chiral order parameter performing a simulation\nof two-flavor QCD with improved Wilson quarks. It has been shown that the\nscaling behavior of the chiral order parameter defined by a Ward-Takahashi\nidentity agrees with the scaling function of the three-dimensional O(4) spin\nmodel at zero chemical potential. We extend the scaling study to finite density\nQCD. Calculating derivatives of the chiral order parameter with respect to the\nchemical potential in two-flavor QCD, the scaling property of chiral phase\ntransition is discussed in the low density region. We moreover calculate the\ncurvature of the phase boundary of the chirl phase transition in the\ntemperature and chemical potential plane assuming the O(4) scaling relation."
    },
    {
        "anchor": "Chiral properties of SU(3) sextet fermions: SU(3) gauge theory with overlap fermions in the 2-index symmetric (sextet)\nand fundamental representations is considered. A priori it is not known what\nthe pattern of chiral symmetry breaking is in a higher dimensional\nrepresentation although the general expectation is that if two representations\nare both complex, the breaking pattern will be the same. This expectation is\nverified for the sextet at N_f = 0 in several exact zero mode sectors. It is\nshown that if the volume is large enough the same random matrix ensemble\ndescribes both the sextet and fundamental Dirac eigenvalues. The number of zero\nmodes for the sextet increases approximately 5-fold relative to the fundamental\nin accordance with the index theorem for small lattice spacing but zero modes\nwhich do not correspond to integer topological charge do exist at larger\nlattice spacings. The zero mode number dependence of the random matrix model\npredictions correctly match the simulations in each sector and each\nrepresentation.",
        "positive": "The nonperturbative contribution to asymptotic masses: In gauge theories, charged particles obey modified dispersion due to medium\ninteractions (forward scattering), leading at high energies $E \\geq T$ to an\nasymptotic mass-squared $m^2_\\infty$. We calculate the infrared part of this\nmass nonperturbatively for the theory of the strong interactions, QCD, through\na lattice treatment of its low-energy effective description, Electrostatic QCD\n(EQCD). Incorporation of these results into a nonperturbative determination of\nthe effective thermal mass will require a still-incomplete next-to-leading\norder perturbative matching of this quantity to full QCD."
    },
    {
        "anchor": "Comment on \"The QCD axion beyond the classical level: A lattice study\": We rebut the claim by Nakamura and Schierholz [1] that the mass of a\npotential axion needs to be no less than ~230MeV pointing out errors in both\ntheir analytic argument and numerical simulations.",
        "positive": "Reweighting complex Langevin trajectories: Although the complex Langevin method can solve the sign problem in\nsimulations of theories with complex actions, the method will yield the wrong\nresults if known validity conditions are not satisfied. We present a novel\nmethod to compute observables for a target ensemble by reweighting complex\ntrajectories generated with the complex Langevin method for an auxiliary\nensemble having itself a complex action. While it is imperative that the\nvalidity conditions be satisfied for the auxiliary ensemble, there are no such\nrequirements for the target ensemble. This allows us to enlarge the\napplicability range of the complex Langevin method. We illustrate this at the\nhand of a one-dimensional partition function and two-dimensional\nstrong-coupling QCD."
    },
    {
        "anchor": "The phase structure of QCD: We review recent results on the phase structure of QCD and bulk QCD\nthermodynamics. In particular we discuss how universal critical scaling related\nto spontaneous breaking of the chiral symmetry manifests itself in recent\nlattice QCD simulations and how the knowledge on non-universal scaling\nparameter can be utilized in the exploration of the QCD phase diagram. We also\nshow how various (generalized) susceptibilities can be employed to characterize\nproperties of QCD matter at low and hight temperatures, related to deconfining\naspects of the QCD transition. Finally, we address the input these lattice QCD\ncalculation can provide for our under standing of the matter created in heavy\nion collisions and in particular on the freeze-out conditions met in the\nhydrodynamic evolution of this matter.",
        "positive": "Interactions of two and three mesons including higher partial waves from\n  lattice QCD: We study two- and three-meson systems composed either of pions or kaons at\nmaximal isospin using Monte Carlo simulations of lattice QCD. Utilizing the\nstochastic LapH method, we are able to determine hundreds of two- and\nthree-particle energy levels, in nine different momentum frames, with high\nprecision. We fit these levels using the relativistic finite-volume formalism\nbased on a generic effective field theory in order to determine the parameters\nof the two- and three-particle K-matrices. We find that the statistical\nprecision of our spectra is sufficient to probe not only the dominant $s$-wave\ninteractions, but also those in $d$ waves. In particular, we determine for the\nfirst time a term in the three-particle K-matrix that contains two-particle $d$\nwaves. We use three $N_f=2+1$ CLS ensembles with pion masses of $200$, $280$,\nand $340\\;$MeV. This allows us to study the chiral dependence of the scattering\nobservables, and compare to the expectations of chiral perturbation theory."
    },
    {
        "anchor": "A calculation of the shear viscosity in SU(3) gluodynamics: We perform a lattice Monte-Carlo calculation of the two-point functions of\nthe energy-momentum tensor at finite temperature in the SU(3) gauge theory.\nUnprecedented precision is obtained thanks to a multi-level algorithm. The\nlattice operators are renormalized non-perturbatively and the classical\ndiscretization errors affecting the correlators are corrected for. A robust\nupper bound for the shear viscosity to entropy density ratio is derived, eta/s\n< 1.0, and our best estimate is eta/s = 0.134(33) at T=1.65Tc under the\nassumption of smoothness of the spectral function in the low-frequency region.",
        "positive": "Chiral restoration of the momentum space quark propagator through Dirac\n  low-mode truncation: We calculate the chirally improved (CI) Landau gauge quark propagator in two\nflavor lattice Quantum Chromodynamics and study thereon the effects of Dirac\nlow-mode removal. The application of tree-level improvement of the propagator\nand tree-level correction of the lattice dressing functions removes the leading\ndiscretization artifacts. We find the dynamically generated mass in the\ninfrared domain of the mass function to dissolve continuously with the\nreduction level and furthermore we observe strong suppression of the\nwave-function renormalization function for small momenta."
    },
    {
        "anchor": "Singlet Free Energies and Renormalized Polyakov Loop in full QCD: We calculate the free energy of a static quark anti-quark pair and the\nrenormalized Polyakov loop in 2+1- and 3- flavor QCD using $16^3 \\times 4$ and\n$16^3 \\times 6$ lattices and improved staggered p4 action. We also compare the\nrenormalized Polyakov loop with the results of our earlier studies.",
        "positive": "Strong-coupling effective action(s) for SU(3) Yang-Mills: We apply strong-coupling expansion techniques to finite-temperature lattice\npure gauge theory, obtaining dimensionally reduced $Z_N$-symmetric effective\ntheories. The analytic mappings between the effective couplings and the\noriginal one, viz. $\\beta$, allow to estimate the transition point $\\beta_c$ of\nthe 4D theory for a large range of the imaginary-time extent $N_\\tau$ of the\nlattice. We study the models for SU(3) via Monte Carlo simulation, finding\nsatisfactory agreement with the critical point of the original theories\nespecially at low $N_\\tau$. We have fixed an error in the group measure used in\narXiv:1010.0951 and provide here the correct numerical results."
    },
    {
        "anchor": "Splittings of low-lying charmonium masses at the physical point: We present high-precision results from lattice QCD for the mass splittings of\nthe low-lying charmonium states. For the valence charm quark, the calculation\nuses Wilson-clover quarks in the Fermilab interpretation. The gauge-field\nensembles are generated in the presence of up, down, and strange sea quarks,\nbased on the improved staggered (asqtad) action, and gluon fields, based on the\none-loop, tadpole-improved gauge action. We use five lattice spacings and two\nvalues of the light sea quark mass to extrapolate the results to the physical\npoint. An enlarged set of interpolating operators is used for a variational\nanalysis to improve the determination of the energies of the ground states in\neach channel. We present and implement a continuum extrapolation within the\nFermilab interpretation, based on power-counting arguments, and thoroughly\ndiscuss all sources of systematic uncertainty. We compare our results for\nvarious mass splittings with their experimental values, namely, the 1S\nhyperfine splitting, the 1P-1S splitting and the P-wave spin-orbit and tensor\nsplittings. Given the uncertainty related to the width of the resonances, we\nfind excellent agreement.",
        "positive": "Perturbation theory predictions and Monte Carlo simulations for the 2-d\n  O(n) non-linear sigma-model: By using the results of a high-statistics (O(10^7) measurements) Monte Carlo\nsimulation we test several predictions of perturbation theory on the O(n)\nnon-linear sigma-model in 2 dimensions. We study the O(3) and O(8) models on\nlarge enough lattices to have a good control on finite-size effects. The\nmagnetic susceptibility and three different definitions of the correlation\nlength are measured. We check our results with large-n expansions as well as\nwith standard formulae for asymptotic freedom up to 4 loops in the standard and\neffective schemes.\n  For this purpose the weak coupling expansions of the energy up to 4 loops for\nthe standard action and up to 3 loops for the Symanzik action are calculated.\nFor the O(3) model we have used two different effective schemes and checked\nthat they lead to compatible results. A great improvement in the results is\nobtained by using the effective scheme based on the energy at 3 and 4 loops. We\nfind that the O(8) model follows very nicely (within few per mille) the\nperturbative predictions. For the O(3) model an acceptable agreement (within\nfew per cent) is found."
    },
    {
        "anchor": "Semi-leptonic decays heavy-light to heavy light: We present results for the QCD matrix elements involved in semi-leptonic\ndecays of B-mesons into pseudo scalar heavy light states. The application of\nNRQCD heavy quarks allows for quark masses around the physical b-quark. We\ninvestigate the dependence of the form factors on the external momenta and\nlooked at the mass dependence at zero recoil. For the first time, results for\nradially excited decay products are presented.",
        "positive": "Lattice calculations of the leading hadronic contribution to (g-2)_mu: We report on our ongoing project to calculate the leading hadronic\ncontribution to the anomalous magnetic moment of the muon a_mu^HLO using two\ndynamical flavours of non-perturbatively O(a) improved Wilson fermions. In this\nstudy, we changed the vacuum polarisation tensor to a combination of local and\npoint-split currents which significantly reduces the numerical effort.\nPartially twisted boundary conditions allow us to improve the momentum\nresolution of the vacuum polarisation tensor and therefore the determination of\nthe leading hadronic contribution to (g-2)_mu. We also extended the range of\nensembles to include a pion mass below 200 MeV which allows us to check the\nnon-trivial chiral behaviour of a_mu^HLO."
    },
    {
        "anchor": "A note on the lattice Dirac-Kaehler equation: A lattice version of the Dirac-Kaehler equation (DKE) describing fermions was\ndiscussed in articles by Becher and Joos. The decomposition of lattice\nDirac-Kaehler fields (inhomogeneous cochains) to lattice Dirac fields remained\nas an open problem. I show that it is possible to extract Dirac fields from the\nDKE and discuss the resulting lattice Dirac equation.",
        "positive": "Hadron Properties just before Deconfinement: We have investigated hadron screening masses, the chiral condensate, and the\npion decay constant close to the deconfinement phase transition in the confined\nphase of QCD. The simulations were done in the quenched approximation, on a\nlattice of size \\mbox{$32^{3}\\times 8$}. We examined temperatures ranging from\n$0.75\\tc$ up to $0.92\\tc$. We see no sign of a temperature dependence in the\nchiral condensate or the meson properties, but some temperature dependence for\nthe nucleon screening mass is not excluded."
    },
    {
        "anchor": "Series expansions without diagrams: We discuss the use of recursive enumeration schemes to obtain low and high\ntemperature series expansions for discrete statistical systems. Using linear\ncombinations of generalized helical lattices, the method is competitive with\ndiagramatic approaches and is easily generalizable. We illustrate the approach\nusing the Ising model and generate low temperature series in up to five\ndimensions and high temperature series in three dimensions. The method is\ngeneral and can be applied to any discrete model. We describe how it would work\nfor Potts models.",
        "positive": "Taming the Leibniz Rule on the Lattice: We study a product rule and a difference operator equipped with Leibniz rule\nin a general framework of lattice field theory. It is shown that the difference\noperator can be determined by the product rule and some initial data through\nthe Leibniz rule. This observation leads to a no-go theorem that it is\nimpossible to construct any difference operator and product rule on a lattice\nwith the properties of (i) translation invariance, (ii) locality and (iii)\nLeibniz rule. We present a formalism to overcome the difficulty by an infinite\nflavor extension or a matrix expression of a lattice field theory."
    },
    {
        "anchor": "The static energy in 2+1+1-flavor QCD: We report on the status of the analysis of the static energy in\n$2+1+1$-flavor QCD. The static energy is obtained by measuring Wilson line\ncorrelators in Coulomb gauge using the HISQ action, yielding the scales\n$r_{0}/a$, $r_{1}/a$, $r_{2}/a$, their ratios, and the string tension $\\sigma\nr_{i}^{2}$. We put emphasis on the possible effects due to the dynamical\ncharm-quark by comparing the lattice results to continuum results of the static\nenergy with and without a massive flavor at two-loop accuracy. We employ\ngauge-field ensembles from the HotQCD and MILC Collaborations.",
        "positive": "Applications of Partially Quenched Chiral Perturbation Theory: Partially quenched theories are theories in which the valence- and sea-quark\nmasses are different. Here, we will discuss the nonanalytic one-loop\ncorrections to some physical quantities, using partially quenched chiral\nperturbation theory. In particular, we will focus on the results for Goldstone\nboson masses to illustrate the general features of our calculation."
    },
    {
        "anchor": "Assorted weak matrix elements involving the bottom quark: As part of a larger project to estimate the fB decay constant, we are\nrecalculating fB_static using a variational smearing method in an effort to\nimprove accuracy. Preliminary results for the static B_B parameter and HQET two\npoint functions are also presented.",
        "positive": "Critical endpoint in the continuum limit and critical endline at $N_{\\rm\n  T}=6$ of the finite temperature phase transition of QCD with clover fermions: We investigate the critical endpoints of the finite temperature phase\ntransition of QCD at zero chemical potential. We employ the\nrenormalization-group improved Iwasaki gauge action and non-perturbatively\nO(a)-improved Wilson-clover fermion action. The critical endpoints are\ndetermined by using the intersection point of kurtosis, employing the\nmulti-parameter, multi-ensemble reweighting method. We present results for the\ncritical endline at $N_{\\rm T}$ = 6 and the continuum extrapolation for the\ncritical endpoint of the SU(3)-flavor symmetric point."
    },
    {
        "anchor": "The pion vector form factor from lattice QCD and NNLO chiral\n  perturbation theory: We present a comprehensive study of the electromagnetic form factor, the\ndecay constant and the mass of the pion computed in lattice QCD with two\ndegenerate O(a)-improved Wilson quarks at three different lattice spacings in\nthe range 0.05-0.08fm and pion masses between 280 and 630MeV at m_pi L >~ 4.\nUsing partially twisted boundary conditions and stochastic estimators, we\nobtain a dense set of precise data points for the form factor at very small\nmomentum transfers, allowing for a model-independent extraction of the charge\nradius. Chiral Perturbation Theory (ChPT) augmented by terms which model\nlattice artefacts is then compared to the data. At next-to-leading order the\neffective theory fails to produce a consistent description of the full set of\npion observables but describes the data well when only the decay constant and\nmass are considered. By contrast, using the next-to-next-to-leading order\nexpressions to perform global fits result in a consistent description of all\ndata. We obtain <r^2_pi>=0.481(33)(13)fm^2 as our final result for the charge\nradius at the physical point. Our calculation also yields estimates for the\npion decay constant in the chiral limit, F_pi/F=1.080(16)(6), the quark\ncondensate, Sigma^{1/3}_MSbar(2GeV)=261(13)(1)MeV and several low-energy\nconstants of SU(2) ChPT.",
        "positive": "Improving the Partial-Global Stochastic Metropolis Update for Dynamical\n  Smeared Link Fermions: We discuss several methods that improve the partial-global stochastic\nMetropolis (PGSM) algorithm for smeared link staggered fermions. We present\nautocorrelation time measurements and argue that this update is feasible even\non reasonably large lattices."
    },
    {
        "anchor": "(Semi)leptonic kaon decays and neutral kaon mixing from lattice QCD: We review recent progress on leptonic and semileptonic kaon decays and\nneutral kaon mixing from lattice QCD.",
        "positive": "Bulk and finite-temperature transitions in SU(3) gauge theories with\n  many light fermions: We investigate finite-temperature transitions in SU(3) lattice gauge theories\nwith Nf=8 and 12 staggered fermions in the fundamental representation. For both\nof these systems, we have observed a strongly-coupled lattice phase in which\nthe single-site shift symmetry of the staggered action is spontaneously broken.\nHere we report new results for finite-temperature transitions on 24^3x12 and\n32^3x16 lattice volumes, contrasting the 8- and 12-flavor systems. While the\nNf=12 finite-temperature transitions accumulate at the bulk transition bounding\nthe strongly-coupled lattice phase, the Nf=8 finite-temperature transitions are\nable to pass through the bulk transition, and behave as expected for a QCD-like\nsystem. We discuss our current results and the work in progress to complete our\ninvestigation of the finite-temperature phase diagram."
    },
    {
        "anchor": "Separation of Infrared and Bulk in Thermal QCD: New thermal phase of QCD, featuring scale invariance in the infrared (IR),\nwas proposed to exist both in the pure-glue (N$_f$=0) and the ``real-world\"\n(N$_f$=2+1) settings. Among key aspects of the proposal is that the system in\nthis {\\em IR phase} separates into two independent components: the\nscale-invariant IR part and the non-invariant bulk. Such scenario requires\nnon-analyticities in the theory and, in case of pure-glue QCD, they were found\nto arise via Anderson-like mobility edges in Dirac spectra ($\\lambda_\\fir \\!=\\!\n0$, $\\pm \\lambda_\\text{A} \\!\\neq\\! 0$) manifested in dimension function\n$d_\\fir(\\lambda)$. Here we present first evidence that this mechanism is also\nat work in ``real-world QCD\" (N$_f$=2+1 theory at physical quark masses and\n$a\\!=\\!0.105\\,$fm), supporting the existence of the proposed IR regime.\nDimensional jump between zero-modes and lowest near-zero modes very close to\nunity ($d_\\fir\\!=\\!3$ vs $d_\\fir \\!\\simeq \\!2$) was found.",
        "positive": "Estimated Errors in |Vcd|/|Vcs| from Semileptonic D Decays: We estimate statistical and systematic errors in the extraction of the CKM\nratio |Vcd|/|Vcs| from exclusive D-meson semileptonic decays using lattice QCD\nand anticipated new experimental results."
    },
    {
        "anchor": "A Mixed Action Analysis of $\u03b7$ and $\u03b7'$ Mesons: We study $\\eta$ and $\\eta'$ mesons and their mixing angle in a mixed action\napproach with so-called Osterwalder-Seiler valence quarks on a Wilson twisted\nmass sea. The gauge configurations have been generated by ETMC for $N_f=2+1+1$\ndynamical quark flavours and for three values of the lattice spacing. The main\nresults are that differences in between the mixed action and the unitary\napproach vanish towards the continuum limit with the expected rate of\n$\\mathcal{O}(a^2)$. The individual size of the lattice artifacts depends,\nhowever, strongly on the observable used to match unitary and valence actions.\nMoreover, we show that for the $\\eta$ mass valence and valence plus sea quark\nmass dependence differ significantly. Hence, in this case a re-tuning of the\nsimulation parameters in the valence sector only is not sufficient to\ncompensate for mismatches in the original quark masses.",
        "positive": "SU(3) deconfining phase transition with finite volume corrections due to\n  a confined exterior: Using the geometry of a double-layered torus we investigate the deconfining\nphase transition of pure SU(3) lattice gauge theory by Markov chain Monte Carlo\nsimulations. In one layer, called \"outside\", the temperature is set below the\ndeconfining temperature and in the other, called \"inside\", it is iterated to a\npseudo-transition temperature. Lattice sizes are chosen in a range suggested by\nthe physical volumes achieved in relativistic heavy ion collisions and both\ntemperatures are kept close enough to stay in the SU(3) scaling region.\nProperties of the transition are studied as function of the volume for three\noutside temperatures. When compared with infinite volume extrapolations, small\nvolume corrections of the deconfining temperature and width become competitive\nwith those found by including quarks. Effective finite size scaling exponents\nof the specific and Polyakov loop susceptibilities are also calculated."
    },
    {
        "anchor": "Extracting Electric Polarizabilities from Lattice QCD: Charged and neutral, pion and kaon electric polarizabilities are extracted\nfrom lattice QCD using an ensemble of anisotropic gauge configurations with\ndynamical clover fermions. We utilize classical background fields to access the\npolarizabilities from two-point correlation functions. Uniform background\nfields are achieved by quantizing the electric field strength with the proper\ntreatment of boundary flux. These external fields, however, are implemented\nonly in the valence quark sector. A novel method to extract charge particle\npolarizabilities is successfully demonstrated for the first time.",
        "positive": "Ginsparg-Wilson Pions Scattering in a Sea of Staggered Quarks: We calculate isospin 2 pion-pion scattering in chiral perturbation theory for\na partially quenched, mixed action theory with Ginsparg-Wilson valence quarks\nand staggered sea quarks. We point out that for some scattering channels, the\npower-law volume dependence of two pion states in nonunitary theories such as\npartially quenched or mixed action QCD is identical to that of QCD. Thus one\ncan extract infinite volume scattering parameters from mixed action\nsimulations. We then determine the scattering length for both 2 and 2+1 sea\nquarks in the isospin limit. The scattering length, when expressed in terms of\nthe pion mass and the decay constant measured on the lattice, has no\ncontributions from mixed valence-sea mesons, thus it does not depend upon the\nparameter, C_Mix, that appears in the chiral Lagrangian of the mixed theory. In\naddition, the contributions which nominally arise from operators appearing in\nthe mixed action O(a^2 m_q) Lagrangian exactly cancel when the scattering\nlength is written in this form. This is in contrast to the scattering length\nexpressed in terms of the bare parameters of the chiral Lagrangian, which\nexplicitly exhibits all the sicknesses and lattice spacing dependence allowed\nby a partially quenched mixed action theory. These results hold for both 2 and\n2+1 flavors of sea quarks."
    },
    {
        "anchor": "Some exact results on the QCD critical point: We show, in a model-independent manner, that the QCD critical point can\nappear only inside the pion condensation phase of the phase-quenched QCD as\nlong as the contribution of flavor-disconnected diagrams is negligible. The\nsign problem is known to be maximally severe in this region, implying that the\nQCD critical point is reachable by the present lattice QCD techniques only if\nthere is an enhancement of the flavor-disconnected contribution at finite\nbaryon chemical potential.",
        "positive": "QCD phase structure in strong magnetic fields: In this proceedings we discuss the natural connection between the reduction\nof neutral pion mass in the vacuum, and the magnetic catalysis as well as the\nreduction of transition temperature in the external magnetic field. We also\npresent the first results on fluctuations of and correlations among conserved\ncharges in strong magnetic fields from lattice QCD computations."
    },
    {
        "anchor": "Meson spectral functions with chirally symmetric lattice fermions: In order to enhance our understanding of spectral functions in lattice QCD\nobtained with the help of the Maximum Entropy Method, we study meson spectral\nfunctions for lattice fermions with chiral symmetry. In particular we analyse\nlattice artefacts for standard overlap, overlap hypercube and domain wall\nfermions in the free field limit. We also present first results for\npseudoscalar spectral functions in dynamical QCD with 2+1 flavours of domain\nwall fermions, using data generated by the UKQCD and RBC collaborations on\nQCDOC machines.",
        "positive": "The derivative expansion of the renormalization group: By writing the flow equations for the continuum Legendre effective action\n(a.k.a. Helmholtz free energy) with respect to a particular form of smooth\ncutoff, and performing a derivative expansion up to some maximum order, a set\nof differential equations are obtained which at FPs (Fixed Points) reduce to\nnon-linear eigenvalue equations for the anomalous scaling dimension $\\eta$.\nIllustrating this by expanding (single component) scalar field theory, in two,\nthree and four dimensions, up to second order in derivatives, we show that the\nmethod is a powerful and robust means of discovering and quantifying\nnon-perturbative continuum limits (continuous phase transitions)."
    },
    {
        "anchor": "Unphysical Poles of Domain Wall Fermions at finite $L_s$: We investigate the origin and behavior of oscillations observed in the hadron\ncorrelators constructed from the domain wall fermion (DWF) for different\nparameters involved in lattice QCD simulations. This oscillatory behavior at\nearly time slices hinders the extraction of excited states in hadron\nspectroscopy. Furthermore, the deviation from exponential decay may have a\nsignificant impact on fermion loop calculations performed on the lattice. We\npresent results for several well-known implementations of the DWF actions. We\nextend the study of Shamir DWF action to include Bori\\c{c}i and M\\\"{o}bius DWF\nactions by analyzing the poles of 4D quark propagator. For each action\nconsidered, we find an unphysical mode when analyzing the pole structure of the\nfree DWF propagator for a finite extent of the $5^{\\text{th}}$ dimension $L_s$,\nand we show that this mode is responsible for the oscillatory behavior observed\nin hadron correlators. We have performed numerical checks on these results and\nhave found that the presence of oscillatory behavior is sensitive to the DWF\nparameters $a_5$, $b_5$, $c_5$ and DW height $M$. To minimize oscillations, our\nresults suggest that one should choose $M a_5<1$ for the Shamir and Bori\\c{c}i\nDWFs, and $M(b_5-c_5)<1$ for M\\\"{o}bius DWF when $M>1$. For each calculation\nconsidered, the Bor\\c{c}i DWF displayed the smallest magnitude of oscillation\nwhen compared to the Shamir and M\\\"{o}bius DWF actions using the same input\nparameters.",
        "positive": "Lattice study of a magnetic contribution to heavy quark momentum\n  diffusion: Heavy quarks placed within a hot QCD medium undergo Brownian motion,\ncharacterized by specific transport coefficients. Their determination can be\nsimplified by expanding them in $T/M$, where $T$ is the temperature and $M$ is\na heavy quark mass. The leading term in the expansion originates from the\ncolour-electric part of a Lorentz force, whereas the next-to-leading order\ninvolves the colour-magnetic part. We measure a colour-magnetic 2-point\ncorrelator in quenched QCD at $T \\sim 1.2 ... 2.0 T_{\\rm c}^{ }$. Employing\nmultilevel techniques and non-perturbative renormalization, a good signal is\nobtained, and its continuum extrapolation can be estimated. Modelling the shape\nof the corresponding spectral function, we subsequently extract the momentum\ndiffusion coefficient, $\\kappa$. For charm (bottom) quarks, the magnetic\ncontribution adds $\\sim 30\\%$ ($10\\%$) to the electric one. The same increases\napply also to the drag coefficient, $\\eta$. As an aside, the colour-magnetic\nspectral function is computed at NLO."
    },
    {
        "anchor": "Pion electric polarizability from lattice QCD: Electromagnetic polarizabilities are important parameters for understanding\nthe interaction between photons and hadrons. For pions these quantities are\npoorly constrained experimentally since they can only be measured indirectly.\nNew experiments at CERN and Jefferson Lab are planned that will measure the\npolarizabilities more precisely. Lattice QCD can be used to compute these\nquantities directly in terms of quark and gluons degrees of freedom, using the\nbackground field method. We present results for the electric polarizability for\ntwo different quark masses, light enough to connect to chiral perturbation\ntheory. These are currently the lightest quark masses used in polarizability\nstudies.",
        "positive": "Smoothing algorithms for projected center-vortex gauge fields: We study the application of $\\mathrm{SU}(3)$ gauge field smoothing methods to\n$\\mathrm{Z}(3)$-projected center-vortex gauge fields. Due to the\nproportionality of the vortex links to the identity, naive applications of\nthese methods are either ineffectual or limited in scope, containing subtle\nissues which are not obviously manifest. To overcome these issues we introduce\ncentrifuge preconditioning, a novel method applied prior to smoothing that\nrotates the links away from the center while preserving the fundamental\nstructure of the vortex field. Additionally, the concept of vortex-preserved\nannealed smoothing is formulated to ensure the smoothing procedure maintains\nthe underlying vortex structure. The application of these new methods in the\ncontext of annealed smoothing applied to vortex fields is shown to successfully\nachieve the desired smoothness condition required for the study of more\nadvanced operators."
    },
    {
        "anchor": "Parton Distribution Function with Non-perturbative Renormalization from\n  Lattice QCD: We present lattice results for the isovector unpolarized parton distribution\nwith nonperturbative RI/MOM-scheme renormalization on the lattice. In the\nframework of large-momentum effective field theory (LaMET), the full\nBjorken-$x$ dependence of a momentum-dependent quasi-distribution is calculated\non the lattice and matched to the ordinary lightcone parton distribution at\none-loop order, with power corrections included. The important step of RI/MOM\nrenormalization that connects the lattice and continuum matrix elements is\ndetailed in this paper. A few consequences of the results are also addressed\nhere.",
        "positive": "Finite-volume energy shift of the three-pion ground state: Using the framework of non-relativistic effective field theory, the\nfinite-volume ground-state energy shift is calculated up-to-and-including\n$O(L^{-6})$ for the system of three pions in the channel with the total isospin\n$I=1$. The relativistic corrections are included perturbatively, up to the same\norder in the inverse of the box size $L$. The obtained explicit expression,\ntogether with the known result for the system with maximal isospin $I=3$, can\nbe used for the extraction of two independent effective three-body couplings\nfrom the measured ground-state spectrum of three pions."
    },
    {
        "anchor": "Comparison of Lattice Coulomb Gauge Wave Functions in Quenched\n  Approximation and with Dynamical Fermions: We present a comparison of Coulomb gauge wave functions from $6/{g^2}=6.0$\nquenched simulations with two simulations which include the effects of\ndynamical fermions: simulations with two flavors of dynamical staggered quarks\nand valence Wilson quarks at $6/{g^2}=5.6$ and simulations with two flavors of\ndynamical Wilson quarks and Wilson valence quarks, at $6/{g^2}=5.3$. The\nspectroscopy of these systems is essentially identical. Parameterizations of\nthe wave functions are presented which can be used as interpolating fields for\nspectroscopy calculations. The sizes of particles are calculated using these\nparameterized wave functions. The resulting sizes are small, approximately half\nthe sizes of the physical states. The charge radius of the neutron, which\nprovides an indication of the asymmetries between the wave functions of up and\ndown quarks, is calculated. Although the size of the nucleon in these\nsimulations is small, the ratio of the charge radius of the neutron to that of\nthe proton is consistent with the physical value. We find no significant\ndifferences between the quenched and dynamical simulations.",
        "positive": "Color flux tubes in $SU(3)$ Yang-Mills theory: an investigation with the\n  connected correlator: In this work we perform an investigation of the flux tube between two static\ncolor sources in four dimensional $SU(3)$ Yang-Mills theory, using the so\ncalled connected correlator. Contrary to most previous studies we do not use\nany smoothing algorithm to facilitate the evaluation of the correlator, that is\nperformed using only stochastically exact techniques. We first examine the\nrenormalization properties of the connected operator, then we present our\nnumerical data for the longitudinal chromoelectric component of the flux tube,\nthat are used to extract the dual superconductivity parameters."
    },
    {
        "anchor": "Strong Coupling Model for String Breaking on the Lattice (LATTICE'98): A model for string breaking on the lattice is formulated using strong\ncoupling ideas. It gives an explicit picture of string breaking, in the\npresence of dynamical quarks, as a mixing process between a string state and a\ntwo-meson state. An analysis of the Wilson loop shows that the evolution of the\nmixing angle as a function of separation may obscure the expected crossover\neffect. If a sufficiently extensive mixing region exists then an appropriate\ncombination of transition amplitudes may help reveal the effect. The\nsensitivity of the mixing region to the values of the meson energy and the\ndynamical quark mass is explored.",
        "positive": "Light hadron spectroscopy with O(a) improved dynamical fermions: We present results for the hadron spectrum and static quark potential from a\nsimulation with two flavours of $O(a)$ improved dynamical Wilson fermions at\n$\\beta=5.2$. We address the issues of sea quark dependence of observables and\nfinite-size effects."
    },
    {
        "anchor": "The second order hydrodynamic transport coefficient $\u03ba$ for the\n  gluon plasma from the lattice: The quark gluon plasma produced in heavy ion collisions behaves like an\nalmost ideal fluid described by viscous hydrodynamics with a number of\ntransport coefficients. The second order coefficient $\\kappa$ is related to a\nEuclidean correlator of the energy-momentum tensor at vanishing frequency and\nlow momentum. This allows for a lattice determination without maximum entropy\nmethods or modelling, but the required lattice sizes represent a formidable\nchallenge. We calculate $\\kappa$ in leading order lattice perturbation theory\nand simulations on $120^3\\times 6,8$ lattices with $a<0.1$ fm. In the\ntemperature range $2T_\\mathrm{c}-10T_\\mathrm{c}$ we find $\\kappa=0.36(15)T^2$.\nThe error covers both a suitably rescaled AdS/CFT prediction as well as,\nremarkably, the result of leading order perturbation theory. This suggests that\nappropriate noise reduction methods on the lattice and NLO perturbative\ncalculations could provide an accurate QCD prediction in the near future.",
        "positive": "Neutrino Oscillation and Lattice QCD: Next generation high-precision neutrino scattering experiments have the goal\nof measuring the as-of-yet unknown parameters governing neutrino oscillation.\nThis effort is hampered by the use of large nuclear targets: secondary\ninteractions within a nucleus can confuse the interpretation of experimental\ndata, leading to ambiguities about the initial neutrino interaction in\nscattering events. The distribution of energies for neutrino events must\ninstead be inferred from the responses of a sum of dissimilar event topologies.\nFor this reason, precise neutrino cross sections on nucleon targets are of\nvital importance to the neutrino oscillation experimental program. On the other\nhand, the necessary experimental data for neutrino scattering with elementary\ntargets are scarce because of the weak interaction cross section, which leads\nto poorly-constrained nucleon and nuclear cross sections. Lattice QCD is\nuniquely positioned to provide the requisite nucleon amplitudes needed to\nenable high-precision oscillation experiments. In particular, LQCD has the\nability to probe axial matrix elements that are challenging to isolate or\ncompletely inaccessible to experiments. In these proceedings, I will discuss\nsome of my work to quantify neutrino cross sections with realistic uncertainty\nestimates, primarily focusing on neutrino quasielastic scattering and the\nnucleon axial form factor. I will also outline how the needs of next-generation\nneutrino oscillation experimental programs can be met with modern dedicated\nLQCD computations."
    },
    {
        "anchor": "On the decoupling of mirror fermions: An approach to the formulation of chiral gauge theories on the lattice is to\nstart with a vector-like theory, but decouple one chirality (the \"mirror\"\nfermions) using strong Yukawa interactions with a chirally coupled \"Higgs\"\nfield. While this is an attractive idea, its viability needs to be tested with\nnonperturbative studies. The model that we study here, the so-called \"3-4-5\"\nmodel, is anomaly free and the presence of massless states in the mirror sector\nis not required by anomaly matching arguments, in contrast to the \"1-0\" model\nthat was studied previously. We have computed the polarization tensor in this\ntheory and find a directional discontinuity that appears to be nonzero in the\nlimit of an infinite lattice, which is equivalent to the continuum limit at\nfixed physical volume. We show that a similar behavior occurs for the free\nmassless Ginsparg-Wilson fermion, where the polarization tensor is known to\nhave a directional discontinuity in the continuum limit. We thus find support\nfor the conclusion that in the continuum limit of the 3-4-5 model, there are\nmassless charged modes in the mirror sector so that it does not decouple from\nthe light sector. The value of the discontinuity we obtain allows for two\ninterpretations: either a chiral gauge theory does not emerge and mirror-sector\nfermions in a chiral anomaly free representation remain massless, or a massless\nvectorlike mirror fermion appears. We end by discussing some questions for\nfuture study.",
        "positive": "Magnetic catalysis and inverse catalysis for heavy pions: We investigate the QCD phase diagram for nonzero background magnetic fields\nusing first-principles lattice simulations. At the physical point (in terms of\nquark masses), the thermodynamics of this system is controlled by two opposing\neffects: magnetic catalysis (enhancement of the quark condensate) at low\ntemperature and inverse magnetic catalysis (reduction of the condensate) in the\ntransition region. While the former is known to be robust and independent of\nthe details of the interactions, inverse catalysis arises as a result of a\ndelicate competition, effective only for light quarks. By performing\nsimulations at different quark masses, we determine the pion mass above which\ninverse catalysis does not take place in the transition region anymore. Even\nfor pions heavier than this limiting value - where the quark condensate\nundergoes magnetic catalysis - our results are consistent with the notion that\nthe transition temperature is reduced by the magnetic field. These findings\nwill be useful to guide low-energy models and effective theories of QCD."
    },
    {
        "anchor": "Equation of State at Finite Density from Imaginary Chemical Potential: We perform two flavor QCD simulations with an imaginary chemical potential\nand measure derivatives of the pressure up to 4th order as a function of the\nimaginary chemical potential and the temperature $T \\in [0.83 T_c, 2 T_c]$. For\ntemperatures $T \\geq T_c$, these derivatives are fitted by a Taylor series in\n$\\mu/T$ about $\\mu=0$. A fit limited to 4th order describes the data poorly at\nall temperatures, showing that we are sensitive to 6th order contributions.\nSimilarly, a 6th order fit fails for temperatures $T_c \\leq T \\leq 1.05 T_c$,\nshowing the need for 8th order terms. Thus, our method may offer a\ncomputational advantage over the direct measurement of Taylor coefficients at\n$\\mu=0$. At temperatures $T \\leq T_c$, we fit our data with a hadron resonance\ngas ansatz. The fit starts to fail at $T \\gtrsim 0.95 T_c$. Using our fits, we\nalso reconstruct the equation of state as a function of real quark and isospin\nchemical potentials.",
        "positive": "New Results From UKQCD Using the Cray T3D: Measuring Gluonic Observables: We report on a set of simulations performed at several values of the lattice\nspacing on the Cray T3D at Edinburgh. Different methods to extract the lattice\nscale from the static quark potential are discussed."
    },
    {
        "anchor": "Computing Masses and Surface Tension from Effective Transfer Matrices: We propose an effective transfer-matrix method that allows a measurement of\ntunnelling correlation lengths that are orders of magnitude larger than the\nlattice extension. Combining this method with a particularly efficient\nimplementation of the multimagnetical algorithm we were able to determine the\ninterface tension of the 3D Ising model close to criticality with a relative\nerror of less than 1 per cent.",
        "positive": "A Framework for Lattice QCD Calculations on GPUs: Computing platforms equipped with accelerators like GPUs have proven to\nprovide great computational power. However, exploiting such platforms for\nexisting scientific applications is not a trivial task. Current GPU programming\nframeworks such as CUDA C/C++ require low-level programming from the developer\nin order to achieve high performance code. As a result porting of applications\nto GPUs is typically limited to time-dominant algorithms and routines, leaving\nthe remainder not accelerated which can open a serious Amdahl's law issue. The\nlattice QCD application Chroma allows to explore a different porting strategy.\nThe layered structure of the software architecture logically separates the\ndata-parallel from the application layer. The QCD Data-Parallel software layer\nprovides data types and expressions with stencil-like operations suitable for\nlattice field theory and Chroma implements algorithms in terms of this\nhigh-level interface. Thus by porting the low-level layer one can effectively\nmove the whole application in one swing to a different platform. The\nQDP-JIT/PTX library, the reimplementation of the low-level layer, provides a\nframework for lattice QCD calculations for the CUDA architecture. The complete\nsoftware interface is supported and thus applications can be run unaltered on\nGPU-based parallel computers. This reimplementation was possible due to the\navailability of a JIT compiler (part of the NVIDIA Linux kernel driver) which\ntranslates an assembly-like language (PTX) to GPU code. The expression template\ntechnique is used to build PTX code generators and a software cache manages the\nGPU memory. This reimplementation allows us to deploy an efficient\nimplementation of the full gauge-generation program with dynamical fermions on\nlarge-scale GPU-based machines such as Titan and Blue Waters which accelerates\nthe algorithm by more than an order of magnitude."
    },
    {
        "anchor": "Corrections to Finite-Size Scaling in the Lattice N-Vector Model for\n  Infinite N: We compute the corrections to finite-size scaling for the N-vector model on\nthe square lattice in the large-N limit. We find that corrections behave as log\nL/L^2. For tree-level improved hamiltonians corrections behave as 1/L^2. In\ngeneral l-loop improvement is expected to reduce this behaviour to 1/(L^2\n\\log^l L). We show that the finite-size-scaling and the perturbative limit do\nnot commute in the calculation of the corrections to finite-size scaling. We\npresent also a detailed study of the corrections for the RP^N-model.",
        "positive": "Covariant gauge on the lattice: a new implementation: We derive a new implementation of linear covariant gauges on the lattice,\nbased on a minimizing functional that can be interpreted as the Hamiltonian of\na spin-glass model in a random external magnetic field. We show that our method\nsolves most problems encountered in earlier implementations, mostly related to\nthe no-go condition formulated by L. Giusti, Nucl. Phys. B 498, 331 (1997). We\ncarry out tests in the SU(2) case in four space-time dimensions. We also\npresent preliminary results for the transverse gluon propagator at different\nvalues of the gauge parameter xi."
    },
    {
        "anchor": "Is there any gender/race bias in hep-lat primary publication?\n  Machine-Learning Evaluation of Author Ethnicity and Gender: In this work, we analyze papers that are classified as primary hep-lat to\nstudy whether there is any race or gender bias in the journal-publication\nprocess. We implement machine learning to predict the race and gender of\nauthors based on their names and look for measurable differences between\npublication outcomes based on author classification. We would like to invite\ndiscussion on how journals can make improvements in their editorial process and\nhow institutions or grant offices should account for these publication\ndifferences in gender and race.",
        "positive": "Topological susceptibility in finite temperature QCD with physical\n  $(u/d, s, c)$ domain-wall quarks: We perform hybrid Monte-Carlo (HMC) simulation of lattice QCD with\n$N_f=2+1+1$ domain-wall quarks at the physical point, on the $64^3 \\times\n(64,20,16,12,10,8,6)$ lattices, each with three lattice spacings. The lattice\nspacings and the bare quark masses are determined on the $64^4$ lattices. The\nresulting gauge ensembles provide a basis for studying finite temperature QCD\nwith $N_f=2+1+1 $ domain-wall quarks at the physical point. In this paper, we\ndetermine the topological susceptibility of the QCD vacuum for $T > T_c \\sim\n150 $ MeV. The topological charge of each gauge configuration is measured by\nthe clover charge in the Wilson flow at the same flow time in physical units,\nand the topological susceptibility $ \\chi_t(a,T) $ is determined for each\nensemble with lattice spacing $a$ and temperature $T$. Using the topological\nsusceptibility $\\chi_t(a,T) $ of 15 gauge ensembles with three lattice spacings\nand different temperatures in the range $T \\sim 155-516 $ MeV, we extract the\ntopological susceptibility $\\chi_t(T)$ in the continuum limit. To compare our\nresults with others, we survey the continuum extrapolated $\\chi_t(T)$ in\nlattice QCD with $N_f=2+1(+1)$ dynamical quarks at/near the physical point, and\ndiscuss their discrepancies. Moreover, a detailed discussion on the reweighting\nmethod for domain-wall fermion is presented."
    },
    {
        "anchor": "Study of the Leutwyler-Smilga regimes: Lessons for full QCD simulations: Some key points out of my recent study of the characteristic features of the\nsmall ($x \\ll 1$), intermediate ($x \\simeq 1$) and large ($x \\gg 1$)\nLeutwyler-Smilga regimes for QCD-type theories in a finite volume ($x = V\n\\Sigma m$) are presented, and a few immediate consequences for full QCD\nsimulations are discussed.",
        "positive": "Detecting Dual Superconductivity in the Ground State of Gauge Theory: We explicitly construct a monopole creation operator: its vacuum expectation\nvalue is an order parameter for dual superconductivity, in that, if different\nfrom zero, it signals a spontaneous breaking of the $U(1)$ symmetry\ncorresponding to monopole charge conservation. This operator is tested by\nnumerical simulations in compact $U(1)$ gauge theory. Our construction provides\na general recipe for detection of the condensation of any topological soliton.\nIn particular our operator can be used to detect dual superconductivity of the\nQCD vacuum."
    },
    {
        "anchor": "The multi-flavor Schwinger model with chemical potential - Overcoming\n  the sign problem with Matrix Product States: During recent years there has been an increasing interest in the application\nof matrix product states, and more generally tensor networks, to lattice gauge\ntheories. This non-perturbative method is sign problem free and has already\nbeen successfully used to compute mass spectra, thermal states and phase\ndiagrams, as well as real-time dynamics for Abelian and non-Abelian gauge\nmodels. In previous work we showed the suitability of the method to explore the\nzero-temperature phase structure of the multi-flavor Schwinger model at\nnon-zero chemical potential, a regime where the conventional Monte Carlo\napproach suffers from the sign problem. Here we extend our numerical study by\nlooking at the spatially resolved chiral condensate in the massless case. We\nrecover spatial oscillations, similar to the theoretical predictions for the\nsingle-flavor case, with a chemical potential dependent frequency and an\namplitude approximately given by the homogeneous zero density condensate value.",
        "positive": "The Index of a Ginsparg-Wilson Dirac operator: A novel feature of a Ginsparg-Wilson lattice Dirac operator is discussed.\nUnlike the Dirac operator for massless fermions in the continuum, this lattice\nDirac operator does not possess topological zero modes for any\ntopologically-nontrivial background gauge fields, even though it is\nexponentially-local, doublers-free, and reproduces correct axial anomaly for\ntopologically-trivial gauge configurations."
    },
    {
        "anchor": "Tadpole renormalization and relativistic corrections in lattice NRQCD: We make a comparison of two tadpole renormalization schemes in the context of\nthe quarkonium hyperfine splittings in lattice NRQCD. Improved gauge-field and\nNRQCD actions are analyzed using the mean-link $u_{0,L}$ in Landau gauge, and\nusing the fourth root of the average plaquette $u_{0,P}$. Simulations are done\nfor $c\\bar c$, $b\\bar c$, and $b\\bar b$ systems. The hyperfine splittings are\ncomputed both at leading and at next-to-leading order in the relativistic\nexpansion. Results are obtained at lattice spacings in the range of about\n0.14~fm to 0.38~fm. A number of features emerge, all of which favor tadpole\nrenormalization using $u_{0,L}$. This includes much better scaling behavior of\nthe hyperfine splittings in the three quarkonium systems when $u_{0,L}$ is\nused. We also find that relativistic corrections to the spin splittings are\nsmaller when $u_{0,L}$ is used, particularly for the $c\\bar c$ and $b\\bar c$\nsystems. We also see signs of a breakdown in the NRQCD expansion when the bare\nquark mass falls below about one in lattice units. Simulations with $u_{0,L}$\nalso appear to be better behaved in this context: the bare quark masses turn\nout to be larger when $u_{0,L}$ is used, compared to when $u_{0,P}$ is used on\nlattices with comparable spacings. These results also demonstrate the need to\ngo beyond tree-level tadpole improvement for precision simulations.",
        "positive": "Automatic differentiation for error analysis: We present ADerrors.jl, a software for linear error propagation and analysis\nof Monte Carlo data. Although the focus is in data analysis in Lattice QCD,\nwhere estimates of the observables have to be computed from Monte Carlo\nsamples, the software also deals with variables with uncertainties, either\ncorrelated or uncorrelated. Thanks to automatic differentiation techniques\nlinear error propagation is performed exactly, even in iterative algorithms\n(i.e. errors in parameters of non-linear fits). In this contribution we present\nan overview of the capabilities of the software, including access to\nuncertainties in fit parameters and dealing with correlated data. The software,\nwritten in julia, is available for download and use in\nhttps://gitlab.ift.uam-csic.es/alberto/aderrors.jl"
    },
    {
        "anchor": "On the phase structure of QCD with Wilson fermions: The phase structure of lattice QCD with Wilson fermions is discussed.\nAnalytic and numerical evidences are given for the spontaneous breaking of\nparity and flavor symmetry, which naturally explains the existence of the\nmassless pion at the critical hopping parameter $K_c$ without recourse to the\nchiral symmetry absent in the Wilson fermion formulation. New numerical\nevidences are also presented for the multiple structure of the critical lines\nin the weak coupling region. A connection between the phase structure and the\nfinite temperature phase transition is briefly mentioned.",
        "positive": "Baryons with Ginsparg-Wilson quarks in a staggered sea: We determine the masses and magnetic moments of the octet baryons in chiral\nperturbation theory formulated for a mixed lattice action of Ginsparg-Wilson\nvalence quarks and staggered sea quarks. Taste-symmetry breaking does not occur\nat next-to-leading order in the combined lattice-spacing and chiral expansion.\nExpressions derived for masses and magnetic moments are required for addressing\nlattice artifacts in mixed-action simulations of these observables."
    },
    {
        "anchor": "Quark propagator in the Landau gauge: The Landau gauge quark propagator in momentum space is investigated using the\nO(a)-improved Sheikholeslami--Wohlert (SW) quark action with a tree-level\nmean-field improved coefficient c_sw. We have studied the unimproved definition\nof the quark propagator, as well as two different tree-level O(a)-improved\npropagators. The ultraviolet behavior of the free lattice propagator is studied\nfor each of these in order to establish which of them provides the most\nreliable description of the quark propagator up to the medium momentum regime.\nA general method of tree-level correction is introduced. This exploits\nasymptotic freedom and removes much of the trivial lattice artifacts at medium\nto high momenta. We obtain results for the quark propagator which are\nqualitatively similar to those typically used in quark models. A simple\nextrapolation of the infrared quark mass M(p^2=0) to the chiral limit gives\n(298+/-8+/-30) MeV, which is consistent with phenomenological expectations.",
        "positive": "Fitting Correlated Data: We discuss fitting correlated data - with the example of hadron mass\nspectroscopy in mind. The main conclusion is that the method of minimising\ncorrelated $\\chi^2$ is unreliable if the data sample is too small."
    },
    {
        "anchor": "102 PFLOPS Lattice QCD quark solver on Fugaku: We present results on the world's first over 100 PFLOPS single precision\nlattice QCD quark solver on the japanese new supercomputer Fugaku. We achieve a\nfactor 38 time speedup from the supercomputer K on the same problem size,\n$192^4$, with 102 PFLOPS, 10% floating-point operation efficiency against\nsingle precision floating-point operation peak. The evaluation region is the\nsingle precision BiCGStab for a Clover-Wilson Dirac matrix with Schwarz\nAlternating Procedure domain decomposition preconditioning using Jacobi\niteration for the local domain matrix inversion.",
        "positive": "Multi-Pion Systems in Lattice QCD and the Three-Pion Interaction: The ground-state energies of 2, 3, 4 and 5 \\pi^+'s in a spatial volume V (2.5\nfm)^3 are computed with lattice QCD. By eliminating the leading contribution\nfrom three-\\pi^+ interactions, particular combinations of these n-\\pi^+\nground-state energies provide precise extractions of the \\pi^+\\pi^+ scattering\nlength in agreement with that obtained from calculations involving only two\n\\pi^+'s. The three-\\pi^+ interaction can be isolated by forming other\ncombinations of the n-\\pi^+ ground-state energies. We find a result that is\nconsistent with a repulsive three-\\pi^+ interaction for m_\\pi < 352 MeV."
    },
    {
        "anchor": "Monte Carlo Study of the 3D Thirring Model: I review three different non-perturbative approaches to the three dimensional\nThirring model: the 1/N_f expansion, Schwinger-Dyson equations, and Monte Carlo\nsimulation. Simulation results are presented to support the existence of a\nnon-perturbative fixed point at a chiral symmetry breaking phase transition for\nN_f=2 and 4, but not for N_f=6. Spectrum calculations for $N_f=2$ reveal\nconventional level ordering near the transition.",
        "positive": "Worm algorithms for the 3-state Potts model with magnetic field and\n  chemical potential: We discuss worm algorithms for the 3-state Potts model with external field\nand chemical potential. The complex phase problem of this system can be\novercome by using a flux representation where the new degrees of freedom are\ndimer and monomer variables. Working with this representation we discuss two\ndifferent generalizations of the conventional Prokof'ev-Svistunov algorithm\nsuitable for Monte Carlo simulations of the model at arbitrary chemical\npotential and evaluate their performance."
    },
    {
        "anchor": "Constraint HMC algorithms for gauge-Higgs models: We present the construction of constraint HMC algorithms for gauge-Higgs\nmodels in order to measure the effective Higgs potential. In particular we\nfocus on SU(2) Gauge-Higgs Unification models in five dimensions. Previous\nsimulations have identified regions in the Higgs phase of these models which\nhave properties of 4D adjoint or Abelian Higgs models. We want to test this\nrelationship by comparing the effective potentials in five and four dimensions.",
        "positive": "N=1 super Yang-Mills on a (3+1) dimensional transverse lattice with one\n  exact supersymmetry: We formulate ${\\cal N}$=1 super Yang-Mills theory in 3+1 dimensions on a two\ndimensional transverse lattice using supersymmetric discrete light cone\nquantization in the large-$N_c$ limit. This formulation is free of fermion\nspecies doubling. We are able to preserve one supersymmetry. We find a rich,\nnon-trivial behavior of the mass spectrum as a function of the coupling\n$g\\sqrt{N_c}$, and see some sort of \"transition\" in the structure of a bound\nstate as we go from the weak coupling to the strong coupling. Using a toy model\nwe give an interpretation of the rich behavior of the mass spectrum. We present\nthe mass spectrum as a function of the winding number for those states whose\ncolor flux winds all the way around in one of the transverse directions. We use\ntwo fits to the mass spectrum and the one that has a string theory\njustification appears preferable. For those states whose color flux is\nlocalized we present an extrapolated value for $m^2$ for some low energy bound\nstates in the limit where the numerical resolution goes to infinity."
    },
    {
        "anchor": "Constrained curve fitting for semi-parametric models with radial basis\n  function networks: Common to many analysis pipelines in lattice gauge theory and the broader\nscientific discipline is the need to fit a semi-parametric model to data. We\npropose a fit method that utilizes a radial basis function network to\napproximate the non-parametric component of such models. The approximate\nparametric model is fit to data using the basin hopping global optimization\nalgorithm. Parameter constraints are enforced through Gaussian priors. The\nviability of our method is tested by examining its use in a finite-size scaling\nanalysis of the $q$-state Potts model and $p$-state clock model with $q=2,3$\nand $p=4,\\infty$.",
        "positive": "Progress in generating gauge ensembles with Stabilized Wilson Fermions: The continued generation of $N_f=2+1$ quark flavor gauge configurations using\nstabilized Wilson fermions by the open lattice initiative (OpenLat) is\nreported. We present the status of our ongoing production and show updates on\nincreasing statistics at the four lattice spacings $a=0.12, 0.094, 0.077$ and\n$0.064$ fm. Aside from the $SU(3)$ flavor symmetric point we discuss\nadvancements in going towards physical pion masses. We show preliminary results\nof the pion decay constants, extending previous results, and discuss further\nvalidation observables on the available ensembles."
    },
    {
        "anchor": "Precision electromagnetic structure of decuplet baryons in the chiral\n  regime: The electromagnetic properties of the baryon decuplet are calculated in\nquenched QCD on a 20^3 x 40 lattice with a lattice spacing of 0.128 fm using\nthe fat-link irrelevant clover (FLIC) fermion action with quark masses\nproviding a pion mass as low as 300 MeV. Magnetic moments and charge radii are\nextracted from the electric and magnetic form factors for each individual quark\nsector. From these, the corresponding baryon properties are constructed. We\npresent results for the higher order moments of the spin-3/2 baryons, including\nthe electric quadrupole moment E2 and the magnetic octupole moment M3. The\nworld's first determination of a non-zero M3 form factor for the Delta baryon\nis presented. With these results we provide a conclusive analysis which shows\nthat decuplet baryons are deformed. We compare the decuplet baryon results from\na similar lattice calculation of the octet baryons. We establish that the\nenvironment sensitivity is far less pronounced in the case of the decuplet\nbaryons compared to that in the octet baryons. A surprising result is that the\ncharge radii of the decuplet baryons are generally smaller than that of the\noctet baryons. The magnetic moment of the Delta^+ reveals a turn over in the\nlow quark mass region, making it smaller than the proton magnetic moment. These\nresults are consistent with the expectations of quenched chiral perturbation\ntheory. A similar turn over is also noticed in the magnetic moment of the\nSigma^*0, but not for Xi^* where only kaon loops can appear in quenched QCD.\nThe electric quadrupole moment of the Omega^- baryon is positive when the\nnegative charge factor is included, and is equal to 0.86 +- 0.12 x 10^-2 fm^2,\nindicating an oblate shape.",
        "positive": "Evaluating Grassmann Integrals: I discuss a simple numerical algorithm for the direct evaluation of multiple\nGrassmann integrals. The approach is exact, suffers no Fermion sign problems,\nand allows arbitrarily complicated interactions. Memory requirements grow\nexponentially with the interaction range and the transverse size of the system.\nLow dimensional systems of order a thousand Grassmann variables can be\nevaluated on a workstation. The technique is illustrated with a spinless\nfermion hopping along a one dimensional chain."
    },
    {
        "anchor": "Remarks on the quantum gravity interpretation of 4D dynamical\n  triangulation: We review some of the phenomenology in 4D dynamical triangulation and explore\nits interpretation in terms of a euclidean effective action of the continuum\nform $\\intx \\sqrt{g} [\\mu -\\frac{1}{16\\pi G} R + \\cdots]$.",
        "positive": "Effective string theory description of the interface free energy: We compare the predictions of the Nambu-Goto effective string model with a\nset of high precision Monte Carlo results for interfaces with periodic boundary\nconditions in the 3D Ising model. We compute the free energy in the covariant\ngauge exactly, up to the inclusion of the Liouville mode. The perturbative\nexpansion of this result agrees both with the result evaluated several years\nago by Dietz and Filk in the physical gauge and with a recent calculation with\nthe Polchinski-Strominger action. We also derive the effective string spectrum\nwhich, because of the different boundary conditions, is very different from the\nwell known one of Arvis. Taking into proper account the effective string\ncorrections and exploiting some technical improvements in the simulations we\nobtain precise estimate of the amplitude ratios T_c/\\sqrt{sigma},\nm_{0++}/\\sqrt{\\sigma} and sigma xi_{2nd}^2. We also discuss the behaviour of\nthe effective string free energy in the dimensional reduction limit (i.e., near\nthe deconfinement transition of the dual 3d gauge Ising model) and its\nrelationship with the 2d Ising model interfaces"
    },
    {
        "anchor": "Four Fermion Interactions in Non-Abelian Gauge Theory: We continue our earlier study of the phase structure of a SU(2) gauge theory\nwhose action contains additional chirally invariant four fermion interactions.\nOur lattice theory uses a reduced staggered fermion formalism to generate two\nDirac flavors in the continuum limit. In the current study we have tried to\nreduce lattice spacing and taste breaking effects by using an improved fermion\naction incorporating stout smeared links. As in our earlier study we observe\ntwo regimes; for weak gauge coupling the chiral condensate behaves as an order\nparameter differentiating a phase at small four fermi coupling where the\ncondensate vanishes from a phase at strong four fermi coupling in which chiral\nsymmetry is spontaneously broken. This picture changes qualitatively when the\ngauge coupling is strong enough to cause confinement; in this case we observe a\nfirst order phase transition for some critical value of the four fermi coupling\nassociated with a strong enhancement of the chiral condensate. We observe that\nthis critical four fermi coupling varies monotonically with bare gauge coupling\n- decreasing, as expected, as the gauge coupling is increased. We have checked\nthat these results remain stable under differing levels of smearing. They\nappear to rule out the appearance of new fixed points associated with chirally\ninvariant four fermion interactions in confining non abelian gauge theories.",
        "positive": "Hybrid Monte Carlo Simulation with Fourier Acceleration of the $N=2$\n  Principal Chiral Model in two Dimensions: Motivated by the similarity to QCD, specifically the property of asymptotic\nfreedom, we simulate the dynamics of the SU(2) $\\times$ SU(2) model in two\ndimensions using the Hybrid Monte Carlo algorithm. By introducing Fourier\nAcceleration, we show that critical slowing down is largely avoided and\nincreases the simulation efficiency by up to a factor of 300. This yields\nnumerical predictions at a precision exceeding that of existing studies and\nallows us to verify the onset of asymptotic scaling."
    },
    {
        "anchor": "Topology in lattice QCD: The status of topology on the lattice is reviewed. Recent results show that\nthe topological susceptibility chi can be unambigously determined. Different\nmethods, if properly implemented, give results consistent with each other. For\nSU(3) the Witten-Veneziano prediction is confirmed. Preliminary results for\nfull QCD are presented. The problem there is that the usual hybrid montecarlo\nalgorithm has severe difficulty to thermalize topology. Possible ways out are\nunder study.",
        "positive": "Lattice QCD for Small Computers: These lectures discuss field theoretic techniques that might allow for\nrealistic simulations of lattice QCD on small computers."
    },
    {
        "anchor": "Proton lifetime bounds from chirally symmetric lattice QCD: We present results for the matrix elements relevant for proton decay in Grand\nUnified Theories (GUTs). The calculation is performed at a fixed lattice\nspacing a^{-1}=1.73(3) GeV using 2+1 flavors of domain wall fermions on\nlattices of size 16^3\\times32 and 24^3\\times64 with a fifth dimension of length\n16. We use the indirect method which relies on an effective field theory\ndescription of proton decay, where we need to estimate the low energy\nconstants, \\alpha = -0.0112(25) GeV^3 and \\beta = 0.0120(26) GeV^3. We relate\nthese low energy constants to the proton decay matrix elements using leading\norder chiral perturbation theory. These can then be combined with experimental\nbounds on the proton lifetime to bound parameters of individual GUTs.",
        "positive": "Topology in the 2d Heisenberg Model under Gradient Flow: The 2d Heisenberg model --- or 2d O(3) model --- is popular in condensed\nmatter physics, and in particle physics as a toy model for QCD. Along with\nother analogies, it shares with 4d Yang-Mills theories, and with QCD, the\nproperty that the configurations are divided in topological sectors. In the\nlattice regularisation the topological charge $Q$ can still be defined such\nthat $Q \\in \\mathbb{Z}$. It has generally been observed, however, that the\ntopological susceptibility $\\chi_{\\rm t} = \\langle Q^2 \\rangle / V$ does not\nscale properly in the continuum limit, i.e. that the quantity $\\chi_{\\rm t}\n\\xi^2$ diverges for $\\xi \\to \\infty$ (where $\\xi$ is the correlation length in\nlattice units). Here we address the question whether or not this divergence\npersists after the application of the Gradient Flow."
    },
    {
        "anchor": "Real Space Renormalization Group Analysis of U(1)-Gauge Theory with\n  theta-term in 2 Dimensions: U(1) lattice gauge theory with $\\theta$-term is investigated by real space\nrenormalization group approach. Flows of renormalized coupling constants are\nanalyzed. For each $\\theta$, renormalization flows converge to a single\ntrajectory irrespective of bare coupling constants of real action. For $\\theta\n\\not= \\pi$ the system is in the confinement phase controlled by an infrared\nfixed point. We found a phase transition at $\\theta = \\pi$. Imaginary part of\nthe action given by $\\theta$-term stays fixed under renormalization group\ntransformations leading to deconfinement.",
        "positive": "The quark-composites approach to QCD: The nucleon-pion interaction: We derive the pion-nucleon interaction in the framework of a new perturbative\napproach to QCD, based on the use of quark composites as fundamental variables.\nThe composites with the quantum numbers of the nucleons are assumed as new\nintegration variables in the Berezin integral which defines the partition\nfunction, while the composites with the quantum numbers of the chiral mesons\nare replaced by auxiliary bosonic fields. The action is modified by the\naddition of irrelevant operators which provide the kinetic terms for these\ncomposites, and the quark action is treated as a perturbation. The resulting\nexpansion has the quark confinement built in. To first order we get the\npion-nucleon interaction of the Yukawa model."
    },
    {
        "anchor": "Exploring the infrared gluon and ghost propagators using large\n  asymmetric lattices: We report on the infrared limit of the quenched lattice Landau gauge gluon\npropagator computed from large asymmetric lattices. In particular, the\ncompatibility of the pure power law infrared solution $(q^2)^{2\\kappa}$ of the\nDyson-Schwinger equations is investigated and the exponent $\\kappa$ is\nmeasured. The lattice data favours $\\kappa \\sim 0.52$, which would imply a\nvanishing zero momentum gluon propagator as predicted by the Kugo-Ojima\nconfinement mechanism and the Zwanziger horizon condition. Results for the\nghost propagator and for the running coupling constant are shown.",
        "positive": "Smooth Random Surfaces from Tight Immersions?: We investigate actions for dynamically triangulated random surfaces that\nconsist of a gaussian or area term plus the {\\it modulus} of the gaussian\ncurvature and compare their behavior with both gaussian plus extrinsic\ncurvature and ``Steiner'' actions."
    },
    {
        "anchor": "The $\\bar{s}s$ content of the D-meson at infinite coupling: We calculate the $\\bar{s}s$ condensate in the D - and B - mesons using the\nunquenched hopping parameter expansion at infinite coupling for the Wilson\nlattice action. We discuss the phenomenological relevance of our result.",
        "positive": "Dynamically-coupled partial-waves in $\u03c1\u03c0$ isospin-2 scattering from\n  lattice QCD: We present the first determination of $\\rho \\pi$ scattering, incorporating\ndynamically-coupled partial-waves, using lattice QCD, a first-principles\nnumerical approach to QCD. Considering the case of isospin-2 $\\rho \\pi$, we\ncalculate partial-wave amplitudes with $J \\le 3$ and determine the degree of\ndynamical mixing between the coupled $S$ and $D$-wave channels with $J^P=1^+$.\nThe analysis makes use of the relationship between scattering amplitudes and\nthe discrete spectrum of states in the finite volume lattice. Constraints on\nthe scattering amplitudes are provided by over one hundred energy levels\ncomputed on two lattice volumes at various overall momenta and in several\nirreducible representations of the relevant symmetry groups. The spectra follow\nfrom variational analyses of matrices of correlations functions computed with\nlarge bases of meson-meson operators. Calculations are performed with\ndegenerate light and strange quarks tuned to the physical strange quark mass so\nthat $m_\\pi \\sim 700$ MeV, ensuring that the $\\rho$ is stable against strong\ndecay. This work demonstrates the successful application of techniques, opening\nthe door to calculations of scattering processes that incorporate the effects\nof dynamically-coupled partial-waves, including those involving resonances or\nbound states."
    },
    {
        "anchor": "Non-perturbative improvement of the axial current in N_f=3 lattice QCD\n  with Wilson fermions and tree-level improved gauge action: The coefficient c_A required for O(a) improvement of the axial current in\nlattice QCD with N_f=3 flavors of Wilson fermions and the tree-level\nSymanzik-improved gauge action is determined non-perturbatively. The standard\nimprovement condition using Schroedinger functional boundary conditions is\nemployed at constant physics for a range of couplings relevant for simulations\nat lattice spacings of ~ 0.09 fm and below. We define the improvement condition\nprojected onto the zero topological charge sector of the theory, in order to\navoid the problem of possibly insufficient tunneling between topological\nsectors in our simulations at the smallest bare coupling. An interpolation\nformula for c_A(g_0^2) is provided together with our final results.",
        "positive": "Safety versus triviality on the lattice: We present the first numerical study of the ultraviolet dynamics of\nnon-asymptotically free gauge-fermion theories at large number of matter\nfields. As testbed theories we consider non-abelian SU(2) gauge theories with\n24 and 48 Dirac fermions on the lattice. For these number of flavors asymptotic\nfreedom is lost and the theories are governed by a gaussian fixed point at low\nenergies. In the ultraviolet they can develop a physical cutoff and therefore\nbe trivial, or achieve an interacting safe fixed point and therefore be\nfundamental at all energy scales. We demonstrate that the gradient flow method\ncan be successfully implemented and applied to determine the renormalized\nrunning coupling when asymptotic freedom is lost. Additionally, we prove that\nour analysis is connected to the gaussian fixed point as our results nicely\nmatch with the perturbative beta function. Intriguingly, we observe that it is\nhard to achieve large values of the renormalized coupling on the lattice. This\nmight be an early sign of the existence of a physical cutoff and imply that a\nlarger number of flavors is needed to achieve the safe fixed point. A more\nconservative interpretation of the results is that the current lattice action\nis unable to explore the deep ultraviolet region where safety might emerge. Our\nwork constitutes an essential step towards determining the ultraviolet fate of\nnon asymptotically free gauge theories."
    },
    {
        "anchor": "Quantum kink and its excitations: We show how detailed properties of a kink in quantum field theory can be\nextracted from field correlation functions. This makes it possible to study\nquantum kinks in a fully non-perturbative way using Monte Carlo simulations. We\ndemonstrate this by calculating the kink mass as well as the spectrum and\napproximate wave functions of its excitations. This way of measuring the kink\nmass has clear advantages over the existing approaches based on creation and\nannihilation operators or the kink free energy. Our methods are straightforward\nto generalise to more realistic theories and other defect types.",
        "positive": "General Ginsparg-Wilson fermions and index: We show rigorously that for general Ginsparg-Wilson fermions the dimensions\nof the geometric eigenspace and of the algebraic one for zero modes agree so\nthat the index theorem on the lattice is not spoiled by unwanted additional\nterms."
    },
    {
        "anchor": "Predictions with Lattice QCD: In recent years, we used lattice QCD to calculate some quantities that were\nunknown or poorly known. They are the $q^2$ dependence of the form factor in\nsemileptonic $D\\to Kl\\nu$ decay, the leptonic decay constants of the $D^+$ and\n$D_s$ mesons, and the mass of the $B_c$ meson. In this paper, we summarize\nthese calculations, with emphasis on their (subsequent) confirmation by\nmeasurements in $e^+e^-$, $\\gamma p$ and $\\bar{p}p$ collisions.",
        "positive": "An Improvement to the Linear Accept/Reject Algorithm: We study the improvement of Kennedy-Kuti's linear accept/reject algorithm\nwith different ordering criterion and modified Bhanot-Kennedy estimator of\n$e^{\\Delta H}$ to reduce probability-bound violation. A new stochastic Monte\nCarlo algorithm to accommodate the probability-bound violation is proposed."
    },
    {
        "anchor": "Eradication of singularities in the next-to-leading order RG evolution\n  for the \u0394S = 1 effective Hamiltonian with 3 quark flavours: We consider the renormalization group evolution for the operators in the\n$\\Delta S=1$ effective Hamiltonian with 3 active quark flavors, which is needed\nin the numerical analysis of data sets for $\\epsilon'/\\epsilon$ calculated in\nlattice QCD. Singularities are present in the original solution of Buras et al.\nat next-to-leading order. We show how these can be eradicated through a method\nof analytic continuation to obtain the correct finite solution in this case.\nFurthermore, we trace the origin of the singularities to a breakdown of the\napproach of Buras et al. in the 3 flavour case, and show how it can be\nrectified so that singularitites are absent from the beginning.",
        "positive": "Gradient flow scale-setting with $N_f=2+1+1$ Wilson-clover twisted-mass\n  fermions: We present a determination of the gradient flow scales $w_0$, $\\sqrt{t_0}$\nand $t_0/w_0$ in isosymmetric QCD, making use of the gauge ensembles produced\nby the Extended Twisted Mass Collaboration (ETMC) with $N_f=2+1+1$ flavours of\nWilson-clover twisted-mass quarks including configurations close to the\nphysical point for all dynamical flavours. The simulations are carried out at\nthree values of the lattice spacing and the scale is set through the PDG value\nof the pion decay constant, yielding $w_0=0.17383(63)$ fm,\n$\\sqrt{t_0}=0.14436(61)$ fm and $t_0/w_0=0.11969(62)$ fm. Finally, fixing the\nkaon mass to its isosymmetric value, we determine the ratio of the kaon and\npion leptonic decay constants to be $f_K/f_{\\pi}=1.1995(44)$."
    },
    {
        "anchor": "Light Glueball masses using the Multilevel Algorithm: Following the multilevel scheme we present an error reduction algorithm for\nextracting glueball masses from monte-carlo simulations of pure SU(3) lattice\ngauge theory. We look at the two lightest states viz. the $0^{++}$ and\n$2^{++}$. Our method involves looking at correlations between large Wilson\nloops and does not require any smearing of links. The error bars we obtain are\nat the moment comparable to those obtained using smeared operators. We also\npresent a comparison of our method with the naive method.",
        "positive": "Form factors for the charm-baryon semileptonic decay $\u039e_c\\to \u039e\\ell\n  \u03bd$ from domain-wall lattice QCD: Recent experimental progress measuring the branching fractions of the\nheavy-baryon semileptonic decays $\\Xi_c\\to \\Xi \\ell \\nu$ has stimulated\ntheoretical interest and motivates precise lattice calculations of the form\nfactors. Here we present such a calculation using domain-wall fermions for the\nup, down, and strange quarks, and an anisotropic clover action for the charm\nquark. We use four ensembles generated by the RBC and UKQCD collaborations,\nwith lattice spacings between 0.111 and 0.073 fm and pion masses ranging from\n420 to 230 MeV. Our preliminary results for the form factors are larger in\nmagnitude than previous lattice results."
    },
    {
        "anchor": "Dirac Strings and the Nonperturbative Photon Propagator in Compact QED: A ``3D'' Mathematica@-generated picture of monopoles and Dirac strings in\n$D=2+1$ compact QED is given. In the Villain approximation, the monopole part\nof the partition function factorizes from the Dirac string part, which\ngenerates the photon propagator. Numerical experiments in exact compact QED\nconfirm this result: photon mass pole $M_\\gamma$, originally nonzero, is\ninsensitive to monopole prohibition but almost vanishes if Dirac strings are\nprohibited.",
        "positive": "Equation of State of Nucleon Matters from Lattice QCD Simulations: Nucleon matters are studied based on QCD. We extract nucleon-nucleon\ninteraction from lattice QCD simulations in a recently developed approach, and\nthen derive the equations of state of the symmetric nuclear matter and the pure\nneutron matter, at zero temperature, in the Brueckner-Hartree-Fock framework.\nWe find that QCD reproduce known features of the symmetric nuclear matter, such\nas the self-binding and saturation, at some values of quark mass. We find also\nthat the pure neutron matter become more stiff at large density as quark mass\ndecrease. We apply these equations of state to neutron star and study its mass\nand radius."
    },
    {
        "anchor": "The Phase Diagram for the anisotropic SU(2) Adjoint Higgs Model in 5D:\n  Lattice Evidence for Layered Structure: We explore, by Monte Carlo and Mean Field methods, the five--dimensional\nSU(2) adjoint Higgs model. We allow for the possibility of different couplings\nalong one direction, describing the so--called anisotropic model. This study is\nmotivated by the possibility of the appearance of four--dimensional layered\ndynamics. Actually, our results lead to the conclusion that the establishment\nof a layered phase in four dimensions described by U(1) symmetry is possible,\nthe extra dimension being confined due to the SU(2) gauge symmetry. The\nfive-dimensional adjoint Higgs model turns out to have a layered phase, in\ncontradistinction with what is known about the pure SU(2) model.",
        "positive": "Two-dimensional lattice for four-dimensional N=4 supersymmetric\n  Yang-Mills: We construct a lattice formulation of a mass-deformed two-dimensional N=(8,8)\nsuper Yang-Mills theory with preserving two supercharges exactly. Gauge fields\nare represented by compact unitary link variables, and the exact supercharges\non the lattice are nilpotent up to gauge transformations and SU(2)_R rotations.\nDue to the mass deformation, the lattice model is free from the vacuum\ndegeneracy problem, which was encountered in earlier approaches, and flat\ndirections of scalar fields are stabilized giving discrete minima representing\nfuzzy S^2. Around the trivial minimum, quantum continuum theory is obtained\nwith no tuning, which serves a nonperturbative construction of the IIA matrix\nstring theory. Moreover, around the minimum of k-coincident fuzzy spheres,\nfour-dimensional N=4 U(k) super Yang-Mills theory with two commutative and two\nnoncommutative directions emerges. In this theory, sixteen supersymmetries are\nbroken by the mass deformation to two. Assuming the breaking is soft, we give a\nscenario leading to undeformed N=4 super Yang-Mills on R^4 without any fine\ntuning. As an evidence for the validity of the assumption, some computation of\n1-loop radiative corrections is presented."
    },
    {
        "anchor": "QCD Phase Diagram with Imaginary Chemical Potential: We report our recent results on the QCD phase diagram obtained from the\nlattice QCD simulation. The location of the phase boundary between hadronic and\nQGP phases in the two-flavor QCD phase diagram is investigated. The imaginary\nchemical potential approach is employed, which is based on Monte Carlo\nsimulations of the QCD with imaginary chemical potential and analytic\ncontinuation to the real chemical potential region.",
        "positive": "The $\u03a5$ and $\u03a5^{\\prime}$ Leptonic Widths, $a_\u03bc^b$ and\n  $m_b$ from full lattice QCD: We determine the decay rate to leptons of the ground-state $\\Upsilon$ meson\nand its first radial excitation in lattice QCD for the first time. We use\nradiatively-improved NRQCD for the $b$ quarks and include $u$, $d$, $s$ and $c$\nquarks in the sea with $u/d$ masses down to their physical values. We find\n$\\Gamma(\\Upsilon \\rightarrow e^+e^-)$ = 1.19(11) keV and\n$\\Gamma(\\Upsilon^{\\prime} \\rightarrow e^+e^-)$ = 0.69(9) keV, both in good\nagreement with experiment. The decay constants we obtain are included in a\nsummary plot of meson decay constants from lattice QCD given in the\nConclusions. We also test time-moments of the vector current-current correlator\nagainst values determined from the $b$ quark contribution to $\\sigma(e^+e^-\n\\rightarrow \\mathrm{hadrons})$ and calculate the $b$-quark piece of the\nhadronic vacuum polarisation contribution to the anomalous magnetic moment of\nthe muon, $a_{\\mu}^b = 0.271(37) \\times 10^{-10}$. Finally we determine the\n$b$-quark mass, obtaining in the $\\overline{MS}$ scheme,\n$\\overline{m}_b(\\overline{m}_b, n_f=5)$ = 4.196(23) GeV, the most accurate\nresult from lattice QCD to date."
    },
    {
        "anchor": "Color confinement, chiral symmetry breaking, and catalytic effect\n  induced by monopole and instanton creations: Our research reveals the relations among monopoles, color confinement,\ninstantons, and chiral symmetry breaking which experiments can detect, by\nnumerical calculations of lattice gauge theory. We first add a monopole and an\nanti-monopole varying their magnetic charges to the gauge field configurations\nin the quenched approximation of quantum chromodynamics (QCD), by applying the\nmonopole creation operator and investigate the effects of the added monopoles\nand anti-monopoles on color confinement. Second, we reveal the quantitative\nrelations among instantons, anti-instantons, and observables using the\neigenvalues and eigenvectors of the overlap Dirac operator, which are\ncalculated using the normal configurations and the configurations with the\nadditional monopoles and anti-monopoles. Finally, we ascertain the outcomes by\ncomparing them with the predictions. We have already discovered the catalytic\neffect: the decay width of the charged pion becomes wider and its lifetime\nbecomes shorter than the experimental outcomes by increasing the number density\nof instantons and anti-instantons. However, the outcomes in the previous study\nwere obtained using one lattice volume and lattice spacing. In this research,\nwe improve the previous study using a variety of configurations of different\nlattice volumes and values of the lattice spacing from low to finite\ntemperatures. The main purposes of this study are to inspect the influences of\nthe finite lattice volume and discretization on the observables and\nquantitative relations that we have obtained in our previous research and to\nacquire the interpolated results at the continuum limit.",
        "positive": "Translational Anomaly in Chiral Gauge Theories on a Torus and the\n  Overlap Formalism: We point out that a fermion determinant of a chiral gauge theory on a 2D\ntorus has a phase ambiguity proportional to the Polyakov loops along the\nboundaries, which can be reproduced by the overlap formalism. We show that the\nrequirement on the fermion determinant that a singularity in the gauge field\ncan be absorbed by a change of the boundary condition for the fermions, is not\ncompatible with translational invariance in general. As a consequence, the\ngauge anomaly for singular gauge transformations discovered by\nNarayanan-Neuberger actually exists in any 2D U(1) chiral gauge theory unless\nthe theory is vector-like. We argue that the gauge anomaly is peculiar to the\noverlap formalism with the Wigner-Brillouin phase choice and that it is not\nnecessarily a property required in the continuum. We also generalize our\nresults to any even dimension."
    },
    {
        "anchor": "Machines and Algorithms: I discuss the evolution of computer architectures with a focus on QCD and\nwith reference to the interplay between architecture, engineering, data motion\nand algorithms. New architectures are discussed and recent performance results\nare displayed. I also review recent progress in multilevel solver and\nintegation algorithms.",
        "positive": "The behavior of the sextic coupling for the the three-dimensional\n  $\u03c6^4 $ theory: In this work we use the lattice regularization method to study the behavior\nof the six point renormalized coupling constant defined at zero momentum for\nthe three-dimensional $\\phi^4 $ theory in the intermediate and strong coupling\ndomain. The result is in good agreement with the corresponding study in the\nIsing limit."
    },
    {
        "anchor": "Field strength correlations in the QCD vacuum at short distance: We determine by numerical simulations on a lattice the gauge--invariant\ntwo--point correlation function of the gauge field strengths in the QCD vacuum,\ndown to a distance of 0.1 fm.",
        "positive": "$B^0_{(s)}$-mixing matrix elements from lattice QCD for the Standard\n  Model and beyond: We calculate---for the first time in three-flavor lattice QCD---the hadronic\nmatrix elements of all five local operators that contribute to neutral $B^0$-\nand $B_s$-meson mixing in and beyond the Standard Model. We present a complete\nerror budget for each matrix element and also provide the full set of\ncorrelations among the matrix elements. We also present the corresponding bag\nparameters and their correlations, as well as specific combinations of the\nmixing matrix elements that enter the expression for the neutral $B$-meson\nwidth difference. We obtain the most precise determination to date of the\nSU(3)-breaking ratio $\\xi = 1.206(18)(6)$, where the second error stems from\nthe omission of charm sea quarks, while the first encompasses all other\nuncertainties. The threefold reduction in total uncertainty, relative to the\n2013 Flavor Lattice Averaging Group results, tightens the constraint from $B$\nmixing on the Cabibbo-Kobayashi-Maskawa (CKM) unitarity triangle. Our\ncalculation employs gauge-field ensembles generated by the MILC Collaboration\nwith four lattice spacings and pion masses close to the physical value. We use\nthe asqtad-improved staggered action for the light valence quarks, and the\nFermilab method for the bottom quark. We use heavy-light meson chiral\nperturbation theory modified to include lattice-spacing effects to extrapolate\nthe five matrix elements to the physical point. We combine our results with\nexperimental measurements of the neutral $B$-meson oscillation frequencies to\ndetermine the CKM matrix elements $|V_{td}| = 8.00(34)(8) \\times 10^{-3}$,\n$|V_{ts}| = 39.0(1.2)(0.4) \\times 10^{-3}$, and $|V_{td}/V_{ts}| =\n0.2052(31)(10)$, which differ from CKM-unitarity expectations by about\n2$\\sigma$. These results and others from flavor-changing-neutral currents point\ntowards an emerging tension between weak processes that are mediated at the\nloop and tree levels."
    },
    {
        "anchor": "Quenched chiral logarithms in lattice QCD with overlap Dirac quarks: We examine quenched chiral logarithms in lattice QCD with overlap Dirac\nquarks. From our data of m_pi^2, we determine the coefficient of quenched\nchiral logarithm delta = 0.203(14), 0.176(17), 0.193(17) and 0.200(13) for\nlattices of sizes 8^3 times 24, 10^3 times 24, 12^3 times 24 and 16^3 times 32\nrespectively. Also, for the first three lattice sizes, we measure the index\nsusceptibility of the overlap Dirac operator, and use the exact relation\nbetween the index susceptibility and the eta' mass in quenched chiral\nperturbation theory to obtain an independent determination of delta =\n0.198(27), 0.173(24), 0.169(22), which are in good agreement with those\ndetermined from m_pi^2.",
        "positive": "Role of inhomogeneities in the flattening of the quantum effective\n  potential: We investigate the role of inhomogeneous field configurations in systems with\na spontaneously broken continuous global symmetry. Spontaneous breaking is\nusually defined as a specific double limit, first infinite volume at finite\nexplicit breaking sources, which are then extrapolated to zero. We consider a\ndifferent approach in which the order parameter is constrained under the path\nintegral, which we simulate using lattice Monte Carlo techniques. In this way\nwe access the flat region of the effective potential and we show that\ninhomogeneous configurations are dominant there. We topologically classify the\nimportant configurations and measure the excess energy stored in the\ninhomogeneities allowing for the definition of a generalized differential\nsurface tension. We show that this contribution becomes negligible at large\nvolumes restoring the flatness of the effective potential in the thermodynamic\nlimit."
    },
    {
        "anchor": "Spectroscopy and Renormalisation Group Flow of a Lattice\n  Nambu-Jona-Lasinio Model: We investigate a lattice Nambu--Jona-Lasinio model both by the Monte Carlo\nmethod and Schwinger-Dyson equations. A comparison allows the discussion of\nfinite size effects and the extrapolation to infinite volume. We pay special\nattention to the identification of particles and resonances. This enables us to\ndiscuss renormalisation group flows in the neighbourhood of the critical\ncoupling where the chiral symmetry breaking phase transition takes place. In no\nregion of the bare parameter space do we find renormalisability for the model.",
        "positive": "Universality in the Gross-Neveu model: We consider universal finite size effects in the large-N limit of the\ncontinuum Gross-Neveu model as well as in its discretized versions with Wilson\nand with staggered fermions. After extrapolation to zero lattice spacing the\nlattice results are compared to the continuum values."
    },
    {
        "anchor": "Lattice QCD at non-zero temperature and density: Soon after the formulation of Quantum Chromodynamics in 1972 its\nregularization on Euclidean space-time lattices had been introduced by Kenneth\nWilson. This paved ground for numerical studies of non-perturbative aspects of\nQCD, first shown by Michael Creutz. Ever since these first lattice QCD\ncalculations the exploration of the QCD phase diagram and the thermodynamics of\nstrong-interaction matter at non-zero temperature and density was pursued\nvigorously. In this brief review I try to highlight some of the results on QCD\nthermodynamics obtain during the last 42 years through lattice QCD\ncalculations.",
        "positive": "Numerical Study of Finite Size Scaling for First Order Phase Transitions: I present results of simulations of the q=10 and q=20 2-d Potts models in the\ntransition region. The asymptotic finite size behavior sets in only for\nextremely large lattices. We learn from this simulation that finite size\nscaling cannot be used to decide that a transition is first order."
    },
    {
        "anchor": "Exploring the phase diagram of sextet QCD: As a follow up to the previous talk about the beta function of SU(3) gauge\ntheory with Nf=2 symmetric representation (clover) fermions [arXiv:0809.2885\n[hep-lat]], we describe our explorations of the beta-kappa plane, away from the\nmassless limit. Our simulations are mostly done on lattices of length L=8 and\n12. We observe a phase transition from a strong coupling confined phase to a\ndeconfined, chirally restored phase. The line of transitions avoids (so far)\nthe location of the infrared fixed point discussed in the last talk.",
        "positive": "Study of unstable particle through the spectral function in O(4)\n  $\u03c6^4$ theory: We test application of the maximum entropy method to decompose the states\ncontributing to the unstable $\\sigma$ correlation function through the spectral\nfunction in the four dimensional O(4) $\\phi^4$ theory. Reliable results are\nobtained for the $\\sigma$ mass and two-particle $\\pi\\pi$ state energy using\nonly the $\\sigma$ correlation function. We also find that the property of the\n$\\sigma$ particle is different between the unstable ($m_{\\sigma}/m_{\\pi}>2$)\nand stable ($m_{\\sigma}/m_{\\pi}<2$) cases."
    },
    {
        "anchor": "Direct Laplacian Center Gauge: We introduce a variation of direct maximal center gauge fixing: the ``direct\nLaplacian'' center gauge. The new procedure overcomes certain shortcomings of\nmaximal center gauge, associated with Gribov copies, that were pointed out by\nBornyakov et al. in hep-lat/0009035.",
        "positive": "Matching lattice and continuum axial-vector and vector currents with\n  NRQCD and HISQ quarks: We match the continuum and lattice axial vector and vector currents at one\nloop in perturbation theory. For the heavy quarks we use the nonrelativistic\nQCD (NRQCD) action and for the light quarks the Highly Improved Staggered Quark\n(HISQ) action. We present results for both massless and massive HISQ quarks and\nas part of the matching procedure we include a discussion of the one loop HISQ\nrenormalisation parameters."
    },
    {
        "anchor": "Masses and decay constants of $D_{(s)}^*$ and $B_{(s)}^*$ mesons in\n  Lattice QCD with $N_f = 2 + 1 + 1$ twisted-mass fermions: We present a lattice calculation of the decay constants and masses of\n$D_{(s)}^*$ and $B_{(s)}^*$ mesons using the gauge configurations produced by\nthe European Twisted Mass Collaboration (ETMC) with $N_f = 2 + 1 + 1$ dynamical\nquarks and at three values of the lattice spacing $a \\sim 0.06 - 0.09$ fm. Pion\nmasses are simulated in the range $m_{\\pi} \\sim 210 - 450$ MeV, while the\nstrange and charm quark masses are close to their physical values. We computed\nthe ratios of vector to pseudoscalar decay constants or masses for various\nvalues of the heavy-quark mass $m_h$ in the range $0.7 m_c^{phys} \\lesssim m_h\n\\lesssim 3 m_c^{phys}$. In order to reach the physical b-quark mass, we\nexploited the HQET prediction that, in the static limit of infinite heavy-quark\nmass, all the considered ratios are equal to one. We obtain: $ f_{D^*}/f_{D} =\n1.078(36),$ $m_{D^*}/m_{D} = 1.0769(79)$, $f_{D^*_{s}}/f_{D_{s}} = 1.087(20)$,\n$m_{D^*_{s}}m_{D_{s}} = 1.0751(56)$, $f_{B^*}/f_{B} = 0.958(22)$,\n$m_{B^*}/m_{B} = 1.0078(15)$, $f_{B^*_{s}}/f_{B_{s}} = 0.974(10)$ and\n$m_{B^*_{s}}/m_{B_{s}} = 1.0083(10)$. Combining them with the corresponding\nexperimental masses from the PDG and the pseudoscalar decay constants\ncalculated by ETMC, we get: $f_{D^*} = 223.5(8.4)~\\mathrm{MeV}$, $m_{D^*} =\n2013(14)~\\mathrm{MeV}$, $f_{D^*_{s}} = 268.8(6.6)~\\mathrm{MeV}$, $ m_{D^*_{s}}\n= 2116(11)~\\mathrm{MeV}$, $f_{B^*} = 185.9(7.2)~\\mathrm{MeV}$, $m_{B^*} =\n5320.5(7.6)~\\mathrm{MeV}$, $f_{B^*_{s}} = 223.1(5.4)~\\mathrm{MeV}$ and\n$m_{B^*_{s}}= 5411.36(5.3)~\\mathrm{MeV}$.",
        "positive": "The QCD sign problem and dynamical simulations of random matrices: At nonzero quark chemical potential dynamical lattice simulations of QCD are\nhindered by the sign problem caused by the complex fermion determinant. The\nseverity of the sign problem can be assessed by the average phase of the\nfermion determinant. In an earlier paper we derived a formula for the\nmicroscopic limit of the average phase for general topology using chiral random\nmatrix theory. In the current paper we present an alternative derivation of the\nsame quantity, leading to a simpler expression which is also calculable for\nfinite-sized matrices, away from the microscopic limit. We explicitly prove the\nequivalence of the old and new results in the microscopic limit. The results\nfor finite-sized matrices illustrate the convergence towards the microscopic\nlimit. We compare the analytical results with dynamical random matrix\nsimulations, where various reweighting methods are used to circumvent the sign\nproblem. We discuss the pros and cons of these reweighting methods."
    },
    {
        "anchor": "The pi-N Sigma term - a lattice investigation: A lattice calculation of the pi-N sigma term is described using dynamical\nstaggered fermions. Preliminary results give a sea term comparable in magnitude\nto the valence term.",
        "positive": "Lattice calculation of coordinate-space vector and axial-vector current\n  correlators in QCD: We study the vector and axial-vector current correlators in perturbative and\nnon-perturbative regimes of QCD. The correlators in Euclidean coordinate space\nare calculated on the lattice using the M\\\"obius domain-wall fermion\nformulation at three lattice spacings covering 0.044--0.080~fm. The dynamical\nquark effects of $2+1$ light flavors are included. The sum $V+A$ and the\ndifference $V-A$ of the vector ($V$) and axial-vector ($A$) current correlators\ncalculated on the lattice after extrapolating to the physical point agree with\nthose converted from the ALEPH experimental data of hadronic $\\tau$ decays. The\nlevel of the agreement in the $V+A$ channel is about $1.3\\sigma$ or smaller in\nthe region of $|x|\\ge0.4$~fm, while that in the $V-A$ channel is about\n$1.8\\sigma$ at $|x|=0.74$~fm and smaller at other distances. We also extract\nthe hiral condensate from the short-distance correlators on the lattice using\nthe PCAC relation. Its result extrapolated to the chiral and continuum limit is\ncompatible with other estimates at low energies."
    },
    {
        "anchor": "Large-$q$ expansion of the two-dimensional $q$-state Potts model by the\n  finite lattice method: We have calculated the large-$q$ expansion for the energy and magnetization\ncumulants at the first order phase transition point in the two-dimensional\n$q$-state Potts model to the 21st or 23rd order in $1/\\sqrt{q}$ using the\nfinite lattice method. The obtained series allow us to give highly convergent\nestimates of the cumulants for $q>4$. The results confirm us the correctness of\nthe conjecture by Bhattacharya {\\em et al.} on the asymptotic behavior of the\nenergy cumulants for $q \\to 4_+$ and a similar new conjecture on the\nmagnetization cumulants.",
        "positive": "Study of finite temperature QCD with 2+1 flavors via Taylor expansion\n  and imaginary chemical potential: We study QCD with 2+1 flavors at nonzero temperature and nonzero chemical\npotential. We present preliminary results obtained from lattice calculations\nperformed with an improved staggered fermions action (p4-action) on lattice\nwith temporal extent N_t = 4 on a line of constant physics with the strange\nquark mass adjusted to its physical value and a pion mass of about 220 MeV. We\ncompute at imaginary chemical potential and compare with Taylor expansion\nresults. We focus our study on a range of temperatures 0.94 < T/T_c < 1.08."
    },
    {
        "anchor": "Generalised Parton Distributions from Lattice Feynman-Hellmann\n  Techniques: We report on the use of Feynman-Hellmann techniques to calculate the\noff-forward Compton amplitude (OFCA) in lattice QCD. At leading-twist, the\nEuclidean OFCA is parameterised by the Mellin moments of generalised parton\ndistributions (GPDs). Hence we extract GPD moments for two values of the soft\nmomentum transfer, $t=-1.10, -2.20\\;\\text{GeV}^2$ and zero-skewness kinematics\nat an unphysical pion mass of $m_{\\pi}\\approx 470\\;\\text{MeV}$. This includes\nthe first determination of the $n=4$ moments.",
        "positive": "Finite-size Scaling of Meson Propagators: Using quenched chiral perturbation theory we compute meson correlation\nfunctions at finite volume and fixed gauge field topology. We also present the\ncorresponding analytical predictions for the unquenched theory at fixed gauge\nfield topology. These results can be used to measure the low-energy parameters\nof the chiral Langrangian from lattice simulations in volumes much smaller than\none pion Compton wavelength."
    },
    {
        "anchor": "Direct Improvement of Hamiltonian Lattice Gauge Theory: We demonstrate that a direct approach to improving Hamiltonian lattice gauge\ntheory is possible. Our approach is to correct errors in the Kogut-Susskind\nHamiltonian by incorporating additional gauge invariant terms. The coefficients\nof these terms are chosen so that the order $a^2$ classical errors vanish. We\nconclude with a brief discussion of tadpole improvement in Hamiltonian lattice\ngauge theory.",
        "positive": "Chiral behavior of light meson form factors in 2+1 flavor QCD with exact\n  chiral symmetry: We present a study of chiral behavior of light meson form factors in QCD with\nthree flavors of overlap quarks. Gauge ensembles are generated at single\nlattice spacing 0.12 fm with pion masses down to 300 MeV. The pion and kaon\nelectromagnetic form factors and the kaon semileptonic form factors are\nprecisely calculated using the all-to-all quark propagator. We discuss their\nchiral behavior using the next-to-next-to-leading order chiral perturbation\ntheory."
    },
    {
        "anchor": "Scaling studies of QCD with the dynamical HISQ action: We study the lattice spacing dependence, or scaling, of physical quantities\nusing the highly improved staggered quark (HISQ) action introduced by the\nHPQCD/UKQCD collaboration, comparing our results to similar simulations with\nthe asqtad fermion action. Results are based on calculations with lattice\nspacings approximately 0.15, 0.12 and 0.09 fm, using four flavors of dynamical\nHISQ quarks. The strange and charm quark masses are near their physical values,\nand the light-quark mass is set to 0.2 times the strange-quark mass. We look at\nthe lattice spacing dependence of hadron masses, pseudoscalar meson decay\nconstants, and the topological susceptibility. In addition to the commonly used\ndetermination of the lattice spacing through the static quark potential, we\nexamine a determination proposed by the HPQCD collaboration that uses the decay\nconstant of a fictitious \"unmixed s bar s\" pseudoscalar meson. We find that the\nlattice artifacts in the HISQ simulations are much smaller than those in the\nasqtad simulations at the same lattice spacings and quark masses.",
        "positive": "Field-strength correlators for QCD in a magnetic background: We present the results of an exploratory study (by means of Monte Carlo\nsimulations on the lattice) of the properties of the gauge-invariant two-point\ncorrelation functions of the gauge-field strengths for $N_f=2$ QCD at zero\ntemperature and in the presence of a magnetic background field: the analysis\nprovides evidence for the emergence of anisotropies in the nonperturbative part\nof the correlators and for an increase of the gluon condensate as a function of\nthe external magnetic field."
    },
    {
        "anchor": "Semileptonic Form Factors: I report the current status of the heavy-light decay constants, the bag\nparameters and the semileptonic form factors. I compare the heavy-light decay\nconstants with Wilson-Wilson and clover-clover fermions. Systematic errors such\nas scale setting and renormalization factors are also discussed. 1/M\ndependences for the heavy-light semileptonic form factors near $q^2 = q^2_max$\nwith clover-clover and NRQCD-Wilson fermions are found to be small.",
        "positive": "Axial anomaly and Ginsparg-Wilson fermions in the Lattice Dirac Sea\n  picture: The axial anomaly equation in 1+1 dimensional QED is obtained on the lattice\nfor fermions obeying the Ginsparg-Wilson relation. We make use of the\nproperties of the Lattice Dirac sea to investigate the connection between the\nanomaly and the Ginsparg-Wilson operator in the Hamiltonian picture. The\ncorrect anomaly is reproduced for gauge fields whose characteristic time is\nmuch larger than the lattice spacing, which is the regime where the adiabatic\napproximation applies. A non-zero Wilson $r$ parameter is necessary to get the\ncorrect anomaly. The anomaly is shown to be independent of $r$ for $r>0.5$. The\ngeneralization to 3+1 dimensions is also discussed."
    },
    {
        "anchor": "On Lattice Calculation of Electric Dipole Moments and Form Factors of\n  the Nucleon: We analyze commonly used expressions for computing the nucleon electric\ndipole form factors (EDFF) $F_3$ and moments (EDM) on a lattice and find that\nthey lead to spurious contributions from the Pauli form factor $F_2$ due to\ninadequate definition of these form factors when parity mixing of lattice\nnucleon fields is involved. Using chirally symmetric domain wall fermions, we\ncalculate the proton and the neutron EDFF induced by the CP-violating quark\nchromo-EDM interaction using the corrected expression. In addition, we\ncalculate the electric dipole moment of the neutron using background electric\nfield that respects time translation invariance and boundary conditions, and\nfind that it decidedly agrees with the new formula but not the old formula for\n$F_3$. Finally, we analyze some selected lattice results for the nucleon EDM\nand observe that after the correction is applied, they either agree with zero\nor are substantially reduced in magnitude, thus reconciling their difference\nfrom phenomenological estimates of the nucleon EDM.",
        "positive": "Scale-dependent mass anomalous dimension from Dirac eigenmodes: We investigate the eigenmodes of the massless Dirac operator to extract the\nscale-dependent fermion mass anomalous dimension gamma_m(mu). By combining\nsimulations on multiple lattice volumes, and when possible several gauge\ncouplings, we are able to measure the anomalous dimension across a wide range\nof energy scales. The method that we present is universal and can be applied to\nany lattice model of interest, including both conformal or chirally broken\nsystems. We consider SU(3) lattice gauge theories with Nf=4, 8 and 12 light or\nmassless fermions. The 4-flavor model behaves as expected for a QCD-like system\nand demonstrates that systematic effects are manageable in practical lattice\ncalculations. Our 12-flavor results are consistent with the existence of an\ninfrared fixed point, at which we predict the scheme-independent mass anomalous\ndimension gamma_m^*=0.32(3). For the 8-flavor model we observe a large\nanomalous dimension across a wide range of energy scales. Further investigation\nis required to determine whether Nf=8 is chirally broken and walking, or if it\npossesses a strongly-coupled conformal fixed point."
    },
    {
        "anchor": "Thermodynamics of 2 and 3 flavour QCD: We discuss recent results on the thermodynamics of QCD in the presence of\nlight dynamical quark degrees of freedom. In particular, we concentrate on an\nanalysis of the flavour and quark mass dependence of the QCD phase diagram, the\nequation of state and the transition temperature. Moreover, we present recent\nresults on the heavy quark free energy.",
        "positive": "Excited isovector mesons using the stochastic LapH method: The spectrum of excited isovector mesons is studied using a 32^3 x 256\nanisotropic lattice with u,d quark masses set to give a pion mass near 240 MeV.\nResults in the bosonic isovector nonstrange symmetry channels of zero total\nmomentum are presented using correlation matrices of unprecedented size. In\naddition to spatially-extended single-meson operators, large numbers of\ntwo-meson operators are used, involving a wide variety of light isovector,\nisoscalar, and strange meson operators of varying relative momenta. All needed\nWick contractions are efficiently evaluated using a stochastic method of\ntreating the low-lying modes of quark propagation that exploits Laplacian\nHeaviside quark-field smearing. Level identification is discussed."
    },
    {
        "anchor": "Update on (2+1+1)-flavor QCD equation of state: We report on preliminary results from the calculations of the QCD equation of\nstate for 2+1+1 flavors using HISQ action. The calculations are performed on\nlattices with temporal extents $N_{\\tau}=6,~8,~10$, and $12$ and aspect ratio\n$N_{\\sigma}/N_{\\tau}=4$. We find that there is a significant contribution to\nthe pressure from charm quarks at temperatures $T> 300$ MeV.",
        "positive": "A Lattice Calculation of Parton Distributions: We report on our exploratory study for the direct evaluation of the parton\ndistribution functions from lattice QCD, based on a recently proposed new\napproach. We present encouraging results using Nf = 2 + 1 + 1 twisted mass\nfermions with a pion mass of about 370 MeV. The focus of this work is a\ndetailed description of the computation, including the lattice calculation, the\nmatching to an infinite momentum and the nucleon mass correction. In addition,\nwe test the effect of gauge link smearing in the operator to estimate the\ninfluence of the Wilson line renormalization, which is yet to be done."
    },
    {
        "anchor": "N* Masses from an Anisotropic Lattice QCD Action: We report N* masses in the spin 3/2 sector from a highly-improved anisotropic\naction. States with both positive and negative parity are isolated via a parity\nprojection method. The extent to which spin projection is needed is examined.\nThe gross features of the splittings from the nucleon ground state show a trend\nconsistent with experimental results at the quark masses explored.",
        "positive": "Renormalisation of composite operators in lattice QCD: perturbative\n  versus nonperturbative: The perturbative and nonperturbative renormalisation of quark-antiquark\noperators in lattice QCD with two flavours of clover fermions is investigated\nwithin the research programme of the QCDSF collaboration. Operators with up to\nthree derivatives are considered. The nonperturbative results based on the\nRI-MOM scheme are compared with estimates from one- and two-loop lattice\nperturbation theory."
    },
    {
        "anchor": "Topology induced first-order phase transitions in lattice quantum\n  gravity: Causal Dynamical Triangulations (CDT) is a lattice formulation of quantum\ngravity, suitable for Monte-Carlo simulations which have been used to study the\nphase diagram of the model. It has four phases characterized by different\ndominant geometries, denoted phase $A$, $B$, $C$ and $C_b$. In this article we\nanalyse the $A-B$ and the $B-C$ {phase} transitions in the case where the\ntopology of space is that of the three-torus. This completes the phase diagram\nof CDT for such a spatial topology. We observe that the order of a phase\ntransition of spacetime geometries can depend on the topology of spacetime.",
        "positive": "Spin models in complex magnetic fields: a hard sign problem: Coupling spin models to complex external fields can give rise to interesting\nphenomena like zeroes of the partition function (Lee-Yang zeroes, edge\nsingularities) or oscillating propagators. Unfortunately, it usually also leads\nto a severe sign problem that can be overcome only in special cases; if the\npartition function has zeroes, the sign problem is even\nrepresentation-independent at these points. In this study, we couple the\nN-state Potts model in different ways to a complex external magnetic field and\ndiscuss the above mentioned phenomena and their relations based on analytic\ncalculations (1D) and results obtained using a modified cluster algorithm\n(general D) that in many cases either cures or at least drastically reduces the\nsign-problem induced by the complex external field."
    },
    {
        "anchor": "Index Theorem and Overlap Formalism with Naive and Minimally Doubled\n  Fermions: We present a theoretical foundation for the index theorem in naive and\nminimally doubled lattice fermions by studying the spectral flow of a Hermitean\nversion of Dirac operators. We utilize the point splitting method to implement\nflavored mass terms, which play an important role in constructing proper\nHermitean operators. We show the spectral flow correctly detects the index of\nthe would-be zero modes which is determined by gauge field topology and the\nnumber of species doublers. Using the flavored mass terms, we present new types\nof overlap fermions from the naive fermion kernels, with a number of flavors\nthat depends on the choice of the mass terms.",
        "positive": "On the running of the bare coupling in SU(N) lattice gauge theories: Interpreting the way that the SU(3) bare lattice coupling runs with the\nlattice spacing is complicated by the fact that there is a smooth cross-over\nregion in which the strong coupling expansion transforms into a weak-coupling\none. For N > 4, however, there is a first order bulk transition that cleanly\nseparates the strong and weak coupling regimes. We find that in this case the\ncalculated string tension can be readily fitted throughout the weak coupling\nregion by a standard 3-loop expression modified by lattice spacing corrections\nof the expected form. While our fits demand the presence of the latter, they do\nnot constrain the perturbative coupling scheme enough to enable us to extract a\nusefully accurate value of a(beta) in units of Lambda_MSbar. To resolve this\nambiguity we turn to SU(3) where we use the Schrodinger Functional coupling\nscheme to extract a value of r_0 x Lambda_SF as a benchmark. We then find that\nthe Parisi mean-field improved coupling scheme closely reproduces this result.\nWe also develop a comparison between different schemes that does not rely on\nthe calculation of any physical quantity and which can therefore be applied\nmuch further into weak coupling. Again the Parisi scheme is favoured over the\nothers that we compare. Using the mean-field scheme we have fitted the values\nof the string tension that have been calculated for N=2 to N=8, to obtain\nLambda_MSbar/sqrt(sigma) = 0.503(2)(40) + 0.33(3)(3)/N^2 for N > 2, where the\nfirst error is statistical and the second is our estimate of the systematic\nerror from all sources."
    },
    {
        "anchor": "High-loop perturbative renormalization constants for Lattice QCD (I):\n  finite constants for Wilson quark currents: We present a high order perturbative computation of the renormalization\nconstants Z_V, Z_A and of the ratio Z_P/Z_S for Wilson fermions. The\ncomputational setup is the one provided by the RI'-MOM scheme. Three- and\nfour-loop expansions are made possible by Numerical Stochastic Perturbation\nTheory. Results are given for various numbers of flavours and/or (within a\nfinite accuracy) for generic n_f up to three loops. For the case n_f=2 we also\npresent four-loop results. Finite size effects are well under control and the\ncontinuum limit is taken by means of hypercubic symmetric Taylor expansions.\nThe main indetermination comes from truncation errors, which should be assessed\nin connection with convergence properties of the series. The latter is best\ndiscussed in the framework of Boosted Perturbation Theory, whose impact we try\nto assess carefully. Final results and their uncertainties show that high-loop\nperturbative computations of Lattice QCD RC's are feasible and should not be\nviewed as a second choice. As a by-product, we discuss the perturbative\nexpansion for the critical mass, also for which results are for generic n_f up\nto three loops, while a four-loop result is obtained for n_f=2.",
        "positive": "Chromoelectric and chromomagnetic correlators at high temperature from\n  gradient flow: The heavy quark diffusion coefficient is encoded in the spectral functions of\nthe chromoelectric and the chromomagnetic correlators that are calculable on\nthe lattice. We study the chromoelectric and the chromomagnetic correlator in\nthe deconfined phase of SU(3) gauge theory using Symanzik flow at two\ntemperatures $1.5T_c$ and $10000 T_c$, with $T_c$ being the phase transition\ntemperature. To control the lattice discretization errors and perform the\ncontinuum limit we use several temporal lattice extents $N_t=16,20,24$ and 28.\nWe observe that the flow time dependence of the chromomagnetic correlator is\nquite different from chromoelectric correlator most likely due to the anomalous\ndimension of the former as has been pointed out recently in the literature."
    },
    {
        "anchor": "Wilson loops in very high order lattice perturbation theory: We calculate Wilson loops of various sizes up to loop order $n=20$ for\nlattice sizes of $L^4 (L=4, 6, 8, 12)$ using the technique of Numerical\nStochastic Perturbation Theory in quenched QCD. This allows to investigate the\nbehaviour of the perturbative series at high orders. We discuss three models to\nestimate the perturbative series: a renormalon inspired fit, a heuristic fit\nbased on an assumed power-law singularity and boosted perturbation theory. We\nhave found differences in the behavior of the perturbative series for smaller\nand larger Wilson loops at moderate $n$. A factorial growth of the coefficients\ncould not be confirmed up to $n=20$. From Monte Carlo measured plaquette data\nand our perturbative result we estimate a value of the gluon condensate\n$<\\frac{\\alpha}{\\pi}GG>$.",
        "positive": "Calculating composite-particle spectra in Hamiltonian formalism and\n  demonstration in 2-flavor QED$_{1+1\\text{d}}$: We consider three distinct methods to compute the mass spectrum of gauge\ntheories in the Hamiltonian formalism: (1) correlation-function scheme, (2)\none-point-function scheme, and (3) dispersion-relation scheme. The first one\nexamines spatial correlation functions as we do in the conventional Euclidean\nMonte Carlo simulations. The second one uses the boundary effect to efficiently\ncompute the mass spectrum. The third one constructs the excited states and fits\ntheir energy using the dispersion relation with selecting quantum numbers. Each\nmethod has its pros and cons, and we clarify such properties in their\napplications to the mass spectrum for the 2-flavor massive Schwinger model at\n$m/g=0.1$ and $\\theta=0$ using the density-matrix renormalization group (DMRG).\nWe note that the multi-flavor Schwinger model at small mass $m$ is a strongly\ncoupled field theory even after the bosonizations, and thus it deserves to\nperform the first-principles numerical calculations. All these methods mostly\nagree and identify the stable particles, pions $\\pi_a$ ($J^{PG}=1^{-+}$), sigma\nmeson $\\sigma$ ($J^{PG}=0^{++}$), and eta meson $\\eta$ ($J^{PG}=0^{--}$). In\nparticular, we find that the mass of $\\sigma$ meson is lighter than twice the\npion mass, and thus $\\sigma$ is stable against the decay process, $\\sigma \\to\n\\pi\\pi$. This is consistent with the analytic prediction using the WKB\napproximation, and, remarkably, our numerical results are so close to the\nWKB-based formula between the pion and sigma-meson masses,\n$M_\\sigma/M_\\pi=\\sqrt{3}$."
    },
    {
        "anchor": "Quark-hadron phase structure, thermodynamics and magnetization of QCD\n  matter: SU($3$) Polyakov linear-sigma model (PLSM) is systematically implemented to\ncharacterize the quark-hadron phase structure and to determine various\nthermodynamic quantities and magnetization of the QCD matter. In mean-field\napproximation, the dependence of the chiral order-parameter on finite magnetic\nfield is also calculated. In a wide range of temperatures and magnetic field\nstrengths, various thermodynamic quantities including trace anomaly, speed of\nsound squared, entropy density, specific heat are presented and some magnetic\nproperties are described, as well. Wherever available these results are\nconfronted to recent lattice QCD calculations. The temperature dependence of\nthese quantities confirms our previous result that the transition temperature\nis reduced with the increase in the magnetic field strength, i.e. QCD matter is\nto be characterized by an inverse magnetic catalysis. Furthermore, the\ntemperature dependence of the magnetization shows that the conclusion that the\nQCD matter has paramagnetic properties slightly below and far above the\npseudo-critical temperature, is confirmed, as well. The excellent agreement\nwith recent lattice calculations proves that our QCD-like approach (PLSM) seems\nto possess the correct degrees-of-freedom in both hadronic and partonic phases\nand describes well the dynamics deriving confined hadrons to deconfined\nquark-gluon plasma.",
        "positive": "Lattice QCD, O.P.E. and the Standard Model: A number of old and new methods for computing $K\\to\\pi\\pi$ amplitudes on the\nlattice are reevaluated. They all involve a non-perturbative determination of\nmatching coefficients. I will show how problems related to operator mixing can\nbe greatly reduced by introducing the O.P.E. of hadronic currents directly on\nthe lattice. Applications to the evaluation of CP-symmetric ($\\Delta I = 1/2$\nrule) and CP-violating ($\\epsilon '/\\epsilon$) processes are presented."
    },
    {
        "anchor": "Non-perturbative running and renormalization of kaon four-quark\n  operators with nf=2+1 domain-wall fermions: We compute the renormalization factors of four-quark operators needed for the\nstudy of $K\\to\\pi\\pi$ decay in the $\\Delta I=3/2$ channel. We evaluate the\nZ-factors at a low energy scale ($\\mu_0=1.145 \\GeV$) using four different\nnon-exceptional RI-SMOM schemes on a large, coarse lattice ($a\\sim 0.14\\fm$) on\nwhich the bare matrix elements are also computed. Then we compute the\nuniversal, non-perturbative, scale evolution matrix of these renormalization\nfactors between $\\mu_0$ and $3\\GeV$. We give the numerical results for the\ndifferent steps of the computation in two different non-exceptional lattice\nschemes, and the connection to $\\msbar$ at $3\\GeV$ is made using one-loop\nperturbation theory.",
        "positive": "Diquark properties from full QCD lattice simulations: We study diquarks on the lattice in the background of a static quark, in a\ngauge-invariant formalism with quark masses down to almost physical $m_\\pi$. We\ndetermine mass differences between diquark channels as well as diquark-quark\nmass differences. The lightest and next-to-lightest diquarks have \"good\"\nscalar, $\\bar{3}_F$, $\\bar{3}_c$, $J^P=0^+$, and \"bad\" axial vector, $6_F$,\n$\\bar{3}_c$, $J^P=1^+$, quantum numbers, and a bad-good mass difference for\n$ud$ flavors, $198(4)~\\rm{MeV}$, in excellent agreement with phenomenological\ndeterminations. Quark-quark attraction is found only in the \"good\" diquark\nchannel. We extract a corresponding diquark size of $\\sim 0.6~\\rm{fm}$ and\nperform a first exploration of the \"good\" diquark shape, which is shown to be\nspherical. Our results provide quantitative support for modeling the low-lying\nbaryon spectrum using good light diquark effective degrees of freedom."
    },
    {
        "anchor": "Color Screening in Quantum Chromodynamics: We review lattice studies of the color screening in the quark-gluon plasma.\nWe put the phenomena related to the color screening into the context of similar\naspects of other physical systems (electromagnetic plasma or cold nuclear\nmatter). We discuss the onset of the color screening and its signature and\nsignificance in the QCD transition region, and elucidate at which temperature\nand to which extent the weak-coupling picture based on hard thermal loop\nexpansion, potential nonrelativistic QCD, or dimensionally-reduced QCD\nquantitatively captures the key properties of the color screening. We discuss\nthe different regimes pertaining to the color screening and thermal\ndissociation of the static quarks in depth for various spatial correlation\nfunctions that are studied on the lattice, and clarify the status of their\nasymptotic screening masses. We finally discuss the screening correlation\nfunctions of dynamical mesons with a wide range of flavor and spin content, and\nhow they conform with expectations for low- and high-temperature behavior.",
        "positive": "The SU(2) Confining Vacuum as a Dual Superconductor: We investigate the dual superconductivity hypothesis in pure SU(2) lattice\ngauge theory. We find evidence of the dual Meissner effect both in the\nmaximally Abelian gauge and without gauge fixing. We also obtain a rather good\nextimation of the string tension using the value of the London penetration\nlength."
    },
    {
        "anchor": "Running coupling and mass anomalous dimension of SU(3) gauge theory with\n  two flavors of symmetric-representation fermions: We have measured the running coupling constant of SU(3) gauge theory coupled\nto Nf=2 flavors of symmetric representation fermions, using the Schrodinger\nfunctional scheme. Our lattice action is defined with hypercubic smeared links\nwhich, along with the larger lattice sizes, bring us closer to the continuum\nlimit than in our previous study. We observe that the coupling runs more slowly\nthan predicted by asymptotic freedom, but we are unable to observe fixed point\nbehavior before encountering a first order transition to a strong coupling\nphase. This indicates that the infrared fixed point found with the thin-link\naction is a lattice artifact. The slow running of the gauge coupling permits an\naccurate determination of the mass anomalous dimension for this theory, which\nwe observe to be small, gamma_m < 0.6, over the range of couplings we can\nreach. We also study the bulk and finite-temperature phase transitions in the\nstrong coupling region.",
        "positive": "Finite size effects and scaling in lattice CP(N-1): We present model predictions for the spectrum of $CP^{N-1}$ in a periodic box\nand use them to interpret the strong finite size effects observed in lattice\nsimulations at medium values of $N$. The asymptotic scaling behaviour of\nalternative lattice actions is discussed along with some aspects of multigrid\nalgorithm efficiency."
    },
    {
        "anchor": "RG flow in an exactly solvable model with fluctuating geometry: A recently proposed renormalization group technique, based on the\nhierarchical structures present in theories with fluctuating geometry, is\nimplemented in the model of branched polymers. The renormalization group\nequations can be solved analytically, and the flow in coupling constant space\ncan be determined.",
        "positive": "QCD phase transition in the chiral limit: We present a lattice QCD based determination of the chiral phase transition\ntemperature in QCD with two massless (up and down) and one strange quark having\nits physical mass. We propose and calculate two novel estimators for the chiral\ntransition temperature for several values of the light quark masses,\ncorresponding to Goldstone pion masses in the range of $58~{\\rm MeV}\\lesssim\nm_\\pi\\lesssim 163~{\\rm MeV}$. The chiral phase transition temperature is\ndetermined by extrapolating to vanishing pion mass using universal scaling\nanalysis. After thermodynamic, continuum and chiral extrapolations we find the\nchiral phase transition temperature $T_c^0=132^{+3}_{-6}$ MeV. We also present\nsome preliminary calculations on interplay of effective $U_A(1)$ restoration\nand chiral phase transition towards chiral limit."
    },
    {
        "anchor": "Lattice study of hybrid static potentials: We report about a recently started project with the aim to compute hybrid\nstatic potentials using lattice gauge theory. First preliminary results for\npure SU(2) Yang-Mills theory are presented.",
        "positive": "Heavy light mesons at a larger lattice spacing: We present results on the spectrum of B and D mesons including radial\nexcitations and discuss the pseudoscalar decay constant. The results are\nobtained at beta=5.7 in the quenched approximation using NRQCD for the heavy\nquark. To study scaling violations we also compare to results obtained at\nbeta=6.0."
    },
    {
        "anchor": "pi-pi Scattering in Twisted Mass Chiral Perturbation Theory: In this report we describe both I=2 and I=0 pi-pi scattering for twisted mass\nlattice QCD utilizing twisted mass chiral perturbation theory at\nnext-to-leading order. Focusing on the lattice spacing (b) corrections, we\ndemonstrate that in the exotic I=2, I_3=+-2 channels, the leading scaling\nviolations of pi-pi scattering at maximal twist begin at O(m_pi^2 b^2). This is\nnot the case in any other isospin channel, for which the scaling violations at\nmaximal twist begin at O(b^2). Furthermore, we demonstrate the existence of a\nmixing between the I=2, I_3 = 0 and I=0 scattering channels due to the breaking\nof isospin symmetry by the twisted mass term. The mixing term, although\nformally next-to-leading order, is relatively large, thus necessitating the use\nof a coupled channel analysis. We argue that this mixing likely renders the\ncomputation of the I=0 channel impractical with twisted mass lattice QCD.",
        "positive": "Equation of State from Lattice QCD Calculations: We provide a status report on the calculation of the Equation of State (EoS)\nof QCD at finite temperature using lattice QCD. Most of the discussion will\nfocus on comparison of recent results obtained by the HotQCD and\nWuppertal-Budapest (W-B) collaborations. We will show that very significant\nprogress has been made towards obtaining high precision results over the\ntemperature range of T=150-700 MeV. The various sources of systematic\nuncertainties will be discussed and the differences between the two\ncalculations highlighted. Our final conclusion is that the lattice results of\nEoS are getting precise enough to justify being used in the phenomenological\nanalysis of heavy ion experiments at RHIC and LHC."
    },
    {
        "anchor": "Toward a systematic analysis of the fourth-root trick: In this note I briefly discuss ideas related to the so-called fourth-root\ntrick. A decomposition of the ``rooted'' fermion effective action into Wilson\nfermions and a nonlocal, lattice spacing suppressed functional is presented,\ncomplete with link interactions. Some proposals are given for analytical,\nnonperturbative studies of the fourth-root trick.",
        "positive": "Light hadronic physics using domain wall fermions in quenched lattice\n  QCD: In the past year domain wall fermion simulations have moved from exploratory\nstages to the point where systematic effects can be studied with different\ngauge couplings, volumes, and lengths in the fifth dimension. Results are\npresented here for the chiral condensate, the light hadron spectrum, and the\nstrange quark mass. We focus especially on the pseudoscalar meson mass and show\nthat, in small volume, the correlators used to compute it can be contaminated\nto different degrees by topological zero modes. In large volume a nonlinear\nextrapolation to the chiral limit, e.g. as expected from quenched chiral\nperturbation theory, is needed in order to have a consistent picture of low\nenergy chiral symmetry breaking effects."
    },
    {
        "anchor": "On tadpole improvement for staggered fermions: An explanation is proposed for the fact that Lepage--Mackenzie tadpole\nimprovement does not work well for staggered fermions. The idea appears to work\nfor all renormalization constants which appear in the staggered fermion\nself-energy. Wilson fermions are also discussed.",
        "positive": "Static quark potential and effective string corrections in the (2+1)-d\n  SU(2) Yang-Mills theory: We report on a very accurate measurement of the static quark potential in\nSU(2) Yang-Mills theory in (2+1) dimensions in order to study the corrections\nto the linear behaviour. We perform numerical simulations at zero and finite\ntemperature comparing our results with the corrections given by the effective\nstring picture in these two regimes. We also check for universal features\ndiscussing our results together with those recently published for the (2+1)-d\nZ(2) and SU(3) pure gauge theories."
    },
    {
        "anchor": "The determination of $\u03b1_s$ by the ALPHA collaboration: We review the ALPHA collaboration strategy for obtaining the QCD coupling at\nhigh scale. In the three-flavor effective theory it avoids the use of\nperturbation theory at $\\alpha > 0.2$ and at the same time has the physical\nscales small compared to the cutoff $1/a$ in all stages of the computation. The\nresult $\\Lambda_\\overline{MS}^{(3)}=332(14)$~MeV is translated to\n$\\alpha_\\overline{MS}(m_Z)=0.1179(10)(2)$ by use of (high order) perturbative\nrelations between the effective theory couplings at the charm and beauty quark\n\"thresholds\". The error of this perturbative step is discussed and estimated as\n$0.0002$.",
        "positive": "Series studies of the Potts model. I: The simple cubic Ising model: The finite lattice method of series expansion is generalised to the $q$-state\nPotts model on the simple cubic lattice.\n  It is found that the computational effort grows exponentially with the square\nof the number of series terms obtained, unlike two-dimensional lattices where\nthe computational requirements grow exponentially with the number of terms. For\nthe Ising ($q=2$) case we have extended low-temperature series for the\npartition functions, magnetisation and zero-field susceptibility to $u^{26}$\nfrom $u^{20}$. The high-temperature series for the zero-field partition\nfunction is extended from $v^{18}$ to $v^{22}$. Subsequent analysis gives\ncritical exponents in agreement with those from field theory."
    },
    {
        "anchor": "Renormalization of four-fermion operators for higher twist calculations: The evaluation of the higher twist contributions to Deep Inelastic Scattering\namplitudes involves a non trivial choice of operator bases for the higher\norders of the OPE expansion of the two hadronic currents. In this talk we\ndiscuss the perturbative renormalization of the four-fermion operators that\nappear in the above bases.",
        "positive": "Phase structure of compactified $SU(N)$ gauge theories in magnetic\n  backgrounds: We discuss the properties of non-abelian gauge theories formulated on\nmanifolds with compactified dimensions and in the presence of fermionic fields\ncoupled to magnetic backgrounds. We show that different phases may emerge,\ncorresponding to different realizations of center symmetry and translational\ninvariance, depending on the compactification radius and on the magnitude of\nthe magnetic field. Our discussion focuses on the case of an $SU(3)$ gauge\ntheory in 4 dimensions with fermions fields in the fundamental representation,\nfor which we provide some exploratory numerical lattice results."
    },
    {
        "anchor": "Magnetic Moments of Delta and Omega^- Baryons with Dynamical Clover\n  Fermions: We calculate the magnetic dipole moment of the Delta(1232) and Omega^-\nbaryons with 2+1-flavors of clover fermions on anisotropic lattices using a\nbackground magnetic field. This is the first dynamical calculation of these\nmagnetic moments using a background field technique. The calculation for\nOmega^- is done at the physical strange quark mass, with the result in units of\nthe physical nuclear magneton mu_Omega^-= -1.93(8)(12) (where the first error\nis statistical and the second is systematic) compared to the experimental\nnumber: -2.02(5). The Delta has been studied at three unphysical quark masses,\ncorresponding to pion mass m_pi = 366, 438, and 548 MeV. The pion mass\ndependence is compared with the behavior obtained from chiral effective field\ntheory.",
        "positive": "Confining force and running coupling with twelve fundamental and two\n  sextet fermions: We investigate two models of much recent interest in lattice Beyond Standard\nModel studies: N_f=2 fermions in the 2-index symmetric (sextet) representation,\nand N_f=12 fermions in the fundamental representation, both with SU(3) gauge\nsymmetry. We present results at fixed lattice spacing for the static fermion\npotential and force as measured via lattice simulations. We show indications\nthat both models are confining in the chiral limit and that neither theory is\nconformal. This is consistent with our findings for the mass spectrum, which\nindicate that chiral symmetry is spontaneously broken in both theories."
    },
    {
        "anchor": "Ward Identity of the Vector Current and the Decay Rate of\n  $\u03b7_c\\rightarrow\u03b3\u03b3$ in Lattice QCD: Using a recently proposed method arXiv:1910.11597 (Yu Meng et al.), we study\nthe two-photon decay rate of $\\eta_c$ using two $N_f=2$ twisted mass gauge\nensembles with lattice spacings $0.067$fm and $0.085$fm. The results obtained\nfrom these two ensembles can be extrapolated in a naive fashion to the\ncontinuum limit, yielding a result that is consistent with the experimental one\nwithin two standard deviations. To be specific, we obtain the results for\ntwo-photon decay of $\\eta_c$ as $\\mathcal{B}(\\eta_c\\rightarrow 2\\gamma)=\n1.29(3)(18)\\times 10^{-4}$ where the first error is statistical and the second\nis our estimate for the systematic error caused by the finite lattice spacing.\nIt turns out that Ward identity for the vector current is of vital importance\nwithin this new method. We find that the Ward identity is violated for local\ncurrent with a finite lattice spacing, however it will be restored after the\ncontinuum limit is taken.",
        "positive": "Building the International Lattice Data Grid: We present the International Lattice Data Grid (ILDG), a loosely federated\ngrid of grids for sharing data from Lattice Quantum Chromodynamics (LQCD)\nsimulations. The ILDG comprises of metadata, file format and web-service\nstandards, which can be used to wrap regional data-grid interfaces, allowing\nseamless access to catalogues and data in a diverse set of collaborating\nregional grids. We discuss the technological underpinnings of the ILDG,\nprimarily the metadata and the middleware, and offer a critique of its various\naspects with the hindsight of the design work and the first full year of\nproduction."
    },
    {
        "anchor": "Evidence of Strong Correlation between Instanton and QCD-monopole on\n  SU(2) Lattice: The correlation between instantons and QCD-monopoles is studied both in the\nlattice gauge theory and in the continuum theory. An analytical study in the\nPolyakov-like gauge, where $A_4(x)$ is diagonalized, shows that the\nQCD-monopole trajectory penetrates the center of each instanton, and becomes\ncomplicated in the multi-instanton system. Using the SU(2) lattice with $16^4$,\nthe instanton number is measured in the singular (monopole-dominating) and\nregular (photon-dominating) parts, respectively. The monopole dominance for the\ntopological charge is found both in the maximally abelian gauge and in the\nPolyakov gauge.",
        "positive": "2+1 flavor QCD calculation of <x> and <x^2>: We calculate the connected insertions of the nucleon three-point function to\nstudy the first few moments of the unpolarized structure functions of the\nnucleon. (The disconnected insertions are discussed elsewhere in these\nproceedings). The calculation employs the CP-PACS/JLQCD 2+1 dynamical clover\nfermions on a 16^3x32 lattice with lattice spacing a=0.1219 fm. The sequential\nsource technique, using non-zero and zero momentum point nucleon field as the\nsecondary source, is applied enabling a study of different currents at various\nmomentum transfer."
    },
    {
        "anchor": "ILDG Middleware Working Group Status Report: We report on the status of the ILDG Middleware Working Group.",
        "positive": "Lattice QCD with Domain-Wall Fermions: We study the quenched lattice QCD using domain-wall fermions at $\\beta=6.0$.\nBehaviors of both pion mass and the explicit breaking term in the axial\nWard-Takahashi identity support the existence of the chiral zero modes. We\nobserve a good agreement between the pion decay constants $f_\\pi$ from both the\nconserved axial current and the local current perturbatively renormalized at\n1-loop. Finally the possible existence of the parity broken phase is also\nexamined in this model."
    },
    {
        "anchor": "Phase diagram of the lattice SU(2) Higgs model: We perform a detailed study of the phase diagram of the lattice Higgs SU(2)\nmodel with fixed Higgs field length. Consistently with previsions based on the\nFradkin Shenker theorem we find a first order transition line with an endpoint\nwhose position we determined. The diagram also shows cross-over lines: the\ncross-over corresponding to the pure SU(2) bulk is also present at nonzero\ncoupling with the Higgs field and merges with the one that continues the line\nof first order transition beyond the critical endpoint. At high temperature the\nfirst order line becomes a crossover, whose position moves by varying the\ntemperature.",
        "positive": "NPR determination of quark masses from the HISQ action: I report on a calculation of bilinear Z-factors needed for determining Z_m\nusing non-perturbative renormalization (NPR) on n_f=2+1+1 HISQ ensembles.\nRI/MOM and RI/SMOM schemes are studied. These will provide an independent\ndetermination of quark masses in addition to other methods being used by the\nHPQCD collaboration."
    },
    {
        "anchor": "The spectrum and mass anomalous dimension of SU(2) adjoint QCD with two\n  Dirac flavours: In this work we present the results of our investigation of \\su{2} gauge\ntheory with two Dirac fermions in the adjoint representation (aQCD2), which\nbelongs to the class of strongly interacting gauge theories that are of basic\ninterest for extensions of the Standard Model. We have done numerical lattice\nsimulations of this theory at two different values of the gauge coupling and\nseveral fermion masses. Our results include the particle spectrum and the mass\nanomalous dimension. The spectrum contains new exotic fermion-gluon states and\nflavour-singlet mesons. The mass anomalous dimension is determined from the\nscaling of the masses and the mode number. The remnant dependence of the\nuniversal mass ratios and mass anomalous dimension on the gauge coupling\nindicates the relevance of scaling corrections, such that earlier estimations\nfor the universal fixed point value of the mass anomalous dimension are\nincomplete without their inclusion.",
        "positive": "Center Dominance and Z2 Vortices in SU(2) Lattice Gauge Theory: We find, in close analogy to abelian dominance in maximal abelian gauge, the\nphenomenon of center dominance in maximal center gauge for $SU(2)$ lattice\ngauge theory. Maximal center gauge is a gauge-fixing condition that preserves a\nresidual $Z_2$ gauge symmetry; ``center projection'' is the projection of\n$SU(2)$ link variables onto $Z_2$ center elements, and ``center dominance'' is\nthe fact that the center-projected link elements carry most of the information\nabout the string tension of the full theory. We present numerical evidence that\nthe thin $Z_2$ vortices of the projected configurations are associated with\n``thick'' $Z_2$ vortices in the unprojected configurations. The evidence also\nsuggests that the thick $Z_2$ vortices may play a significant role in the\nconfinement process."
    },
    {
        "anchor": "The hadronic vacuum polarization contribution to $(g-2)_\u03bc$ from $2+1$\n  flavours of O($a$) improved Wilson quarks: We report on our ongoing project to determine the leading-order hadronic\nvacuum polarisation contribution to the muon $g-2$, using ensembles with\n$N_f=2+1$ flavours of O($a$) improved Wilson quarks generated by the CLS\neffort, with pion masses down to the physical value. We employ O($a$) improved\nversions of the local and conserved vector currents to compute the\ncontributions of the light, strange and charm quarks to $(g-2)_\\mu$, using the\ntime-momentum representation. We perform a detailed investigation of the\nsystematic effects arising from constraining the long-distance regime of the\nvector correlator. To this end we make use of auxiliary calculations in the\niso-vector channel using distillation and the L\\\"uscher formalism. Our results\nare corrected for finite-volume effects by computing the timelike pion form\nfactor in finite and infinite volume. For certain parameter choices, the\ncorrections computed in this way can also be confronted with results determined\non different volumes. Currently, the overall precision of our results is\nlimited by the uncertainties in the lattice scale.",
        "positive": "Nuclear forces on the lattice: Recent studies by the NPLQCD collaboration of hadronic interactions using\nlattice QCD are reviewed, with an emphasis on a recent calculation of\nmeson-baryon scattering lengths. Ongoing high-statistics calculations of baryon\ninteractions are also reviewed. In particular, new insights into the\nsignal/noise problems that plague correlation functions involving baryons are\ndiscussed."
    },
    {
        "anchor": "On The Origin of the OZI Rule in QCD: The OZI rule is prominent in hadronic phenomena only because OZI violation is\ntypically an order of magnitude smaller than expected from large N_c arguments.\nWith its standard ^3P_0 pair creation operator for hadronic decays by flux tube\nbreaking, the quark model respects the OZI rule at tree level and exhibits the\ncancellations between OZI-violating meson loop diagrams required for this\ndramatic suppression. However, if the quark model explanation for these\ncancellations is correct, then OZI violation would be expected to be large in\nthe nonet with the same quantum numbers as the pair creation operator: the\n0^{++} mesons. Experiment is currently unable to identify these mesons, but we\nreport here on a lattice QCD calculation which confirms that the OZI rule\narises from QCD in the vector and axial vector mesons as observed, and finds a\nlarge violation of the rule in the scalar mesons as anticipated by the quark\nmodel. In view of this result, we make some remarks on possible connections\nbetween the ^3P_0 pair creation model, scalar mesons, and the U_A(1) anomaly\nresponsible for the large OZI violation which drives the \\eta' mass. In\nparticular, we note that our result favors the large N_c and not the instanton\ninterpretation of the solution to the \\eta' mass problem.",
        "positive": "Hadronic vacuum polarization and muon g-2 from magnetic susceptibilities\n  on the lattice: We present and test a new method to compute the hadronic vacuum polarization\nfunction in lattice simulations. This can then be used, e.g., to determine the\nleading hadronic contribution to the anomalous magnetic moment of the muon. The\nmethod is based on computing susceptibilities with respect to external\nelectromagnetic plane wave fields and allows for a precision determination of\nboth the connected and the disconnected contributions to the vacuum\npolarization. We demonstrate that the statistical errors obtained with our\nmethod are much smaller than those quoted in previous lattice studies,\nprimarily due to a very effective suppression of the errors of the disconnected\nterms. These turn out to vanish within small errors, enabling us to quote an\nupper limit. We also comment on the accuracy of the vacuum polarization\nfunction determined from present experimental R-ratio data."
    },
    {
        "anchor": "Chiral-even axial twist-3 GPDs of the proton from lattice QCD: This work presents the first lattice-QCD calculation of the twist-3 axial\nquark GPDs for the proton using the large-momentum effective theory approach.\nWe calculate matrix elements with momentum-boosted proton states and a\nnon-local axial operator. The calculation is performed using one ensemble of\ntwo degenerate light, a strange and a charm quark ($N_f=2+1+1$) of maximally\ntwisted mass fermions with a clover term. The ensemble has a volume\n$32^3\\times64$, lattice spacing 0.0934 fm, and corresponds to a pion mass of\n260 MeV. The matrix elements are calculated for three values of the proton\nmomentum, namely 0.83, 1.25, and 1.67 GeV. The light-cone GPDs are defined in\nthe symmetric frame, which we implement here with a (negative) 4-momentum\ntransfer squared of 0.69, 1.38, and 2.76 GeV$^2$, all at zero skewness. We also\nconduct several consistency checks, including assessing the local limit of the\ntwist-3 GPDs and examining the Burkhardt-Cottingham-type as well as\nEfremov-Teryaev-Leader-type sum rules.",
        "positive": "Lattice quark masses: a non-perturbative measurement: We discuss the renormalization of different definitions of quark masses in\nthe Wilson and the tree-level improved SW-Clover fermionic action. For the\nimproved case we give the correct relationship between the quark mass and the\nhopping parameter. Using perturbative and non-perturbative renormalization\nconstants, we extract quark masses in the $\\MSbar$ scheme from Lattice QCD in\nthe quenched approximation at $\\beta=6.0$, $\\beta=6.2$ and $\\beta=6.4$ for both\nactions. We find: $\\bar{m}^{\\MSbar}(2 GeV)=5.7 \\pm 0.1 \\pm 0.8$ MeV,\n$m_s^{\\MSbar}(2GeV)= 130 \\pm 2 \\pm 18 $ MeV and $m_c^{\\MSbar}(2 GeV) = 1662\\pm\n30\\pm 230$ MeV."
    },
    {
        "anchor": "$\u03c1$ and $K^*$ resonances on the lattice at nearly physical quark\n  masses and $N_f=2$: Working with a pion mass $m_\\pi \\approx 150$ MeV, we study $\\pi\\pi$ and\n$K\\pi$ scattering using two flavours of non-perturbatively improved Wilson\nfermions at a lattice spacing $a\\approx 0.071$ fm. Employing two lattice\nvolumes with linear spatial extents of $N_s=48$ and $N_s=64$ points and moving\nframes, we extract the phase shifts for p-wave $\\pi\\pi$ and $K\\pi$ scattering\nnear the $\\rho$ and $K^*$ resonances.Comparing our results to those of previous\nlattice studies, that used pion masses ranging from about 200 MeV up to 470\nMeV, we find that the coupling $g_{\\rho\\pi\\pi}$ appears to be remarkably\nconstant as a function of $m_{\\pi}$.",
        "positive": "Hyperon Form Factors from N_f=2+1 QCD: We present results from the QCDSF/UKQCD collaboration for the electromagnetic\nand semi-leptonic form factors for the hyperons. The simulations are performed\non our new ensembles generated with 2+1 flavours of dynamical O(a)-improved\nWilson fermions. A unique feature of these configurations is that the quark\nmasses are tuned so that the singlet quark mass is held fixed at its physical\nvalue. We use 5 such choices of the individual quark masses on 24^3x48 lattices\nwith a lattice spacing of about 0.078 fm."
    },
    {
        "anchor": "Chiral limit of QCD: This talk contains an analysis of quenched chiral perturbation theory and its\nconsequences. The chiral behavior of a number of quantities such as the pion\nmass $m_\\pi^2$, the Bernard-Golterman ratios $R$ and $\\chi$, the masses of\nnucleons, and the kaon B-parameter are examined to see if the singular terms\ninduced by the additional Goldstone boson,$\\eta'$, are visible in present data.\nThe overall conclusion (different from what I presented at the lattice meeting)\nof this analysis is that, with some caveats on the extra terms induced by\n$\\eta'$ loops, the standard expressions break down when extrapolating the\nquenched data with $m_q < m_s/2$ to physical light quarks. I then show that due\nto the single and double poles in the quenched $\\eta'$, the axial charge of the\nproton cannot be calculated using the Adler-Bell-Jackiw anomaly condition. I\nconclude with a review of the status of the calculation of light quark masses\nfrom lattice QCD.",
        "positive": "The QCD Equation of State: Results for the equation of state in 2+1 flavor QCD at zero net baryon\ndensity using the Highly Improved Staggered Quark (HISQ) action by the HotQCD\ncollaboration are presented. The strange quark mass was tuned to its physical\nvalue and the light (up/down) quark masses fixed to $m_l = 0.05m_s$\ncorresponding to a pion mass of 160 MeV in the continuum limit. Lattices with\ntemporal extent $N_t=6$, 8, 10 and 12 were used. Since the cutoff effects for\n$N_t>6$ were observed to be small, reliable continuum extrapolations of the\nlattice data for the phenomenologically interesting temperatures range $130\n\\mathord{\\rm MeV} < T < 400 \\mathord{\\rm MeV}$ could be performed. We discuss\nstatistical and systematic errors and compare our results with other published\nworks."
    },
    {
        "anchor": "Wave Function of the Roper from Lattice QCD: We apply the eigenvectors from a variational analysis in lattice QCD to\nsuccessfully extract the wave function of the Roper state, and a higher mass\nP_11 state of the nucleon. We use the 2+1 flavour 32^3x64 PACS-CS\nconfigurations at a near physical pion mass of 156 MeV. We find that both\nstates exhibit a structure consistent with a constituent quark model. The Roper\nd-quark wave function contains a single node consistent with a 2S state, and\nthe third state wave function contains two, consistent with a 3S state. A\ndetailed comparison with constituent quark model wave functions is carried out,\nobtained from a Coulomb plus ramp potential. These results validate the\napproach of accessing these states by constructing a variational basis composed\nof different levels of fermion source and sink smearing. Furthermore,\nsignificant finite volume effects are apparent for these excited states which\nmix with multi-particle states, driving their masses away from physical values\nand enabling the extraction of resonance parameters from lattice QCD\nsimulations.",
        "positive": "Meson thermal masses at different temperatures: We determine the ground state meson masses at low temperature using\nsimulations with $2+1$ flavours of improved Wilson-clover fermions.\nSubsequently we study the effect of increasing the temperature of the hadron\ngas, including the transition to the quark-gluon plasma, as well as the\nrestoration of $SU(2)_A$ chiral symmetry. We use the FASTSUM anisotropic,\nfixed-scale Generation2L ensembles and consider mesons with light, strange and\ncharm content."
    },
    {
        "anchor": "Dirac and Pauli form factors from lattice QCD: We present a comprehensive analysis of the electromagnetic form factors of\nthe nucleon from a lattice simulation with two flavors of dynamical\nO(a)-improved Wilson fermions. A key feature of our calculation is that we make\nuse of an extensive ensemble of lattice gauge field configurations with four\ndifferent lattice spacings, multiple volumes, and pion masses down to m_\\pi ~\n180 MeV. We find that by employing Kelly-inspired parametrizations for the\nQ^2-dependence of the form factors, we are able to obtain stable fits over our\ncomplete ensemble. Dirac and Pauli radii and the anomalous magnetic moments of\nthe nucleon are extracted and results at light quark masses provide evidence\nfor chiral non-analytic behavior in these fundamental observables.",
        "positive": "The mass of the b-quark from lattice NRQCD and lattice perturbation\n  theory: We present a determination of the b-quark mass accurate through O(\\alpha_s^2)\nin perturbation theory and including partial contributions at O(\\alpha_s^3).\nNonperturbative input comes from the calculation of the Upsilon and B_s\nenergies in lattice QCD including the effect of u, d and s sea quarks. We use\nan improved NRQCD action for the b-quark. This is combined with the heavy quark\nenergy shift in NRQCD determined using a mixed approach of high-beta simulation\nand automated lattice perturbation theory. Comparison with experiment enables\nthe quark mass to be extracted: in the MS bar scheme we find m_b(m_b) =\n4.166(43) GeV."
    },
    {
        "anchor": "Comparative study of topological charge: Comparative study of topological charge is performed. Topological charges are\nmeasured by a cloverleaf operator on smoothed gauge configurations. Various\ntypes of smoothing techniques are employed. Agreement of topological charges in\nfermionic and gluonic definitions is examined. High consistency is observed\nbetween topological charges obtained by improved smoothing methods and those by\nthe index theorem with the overlap-Dirac operator.",
        "positive": "A qubit model for U(1) lattice gauge theory: A conceptually simple model for strongly interacting compact U(1) lattice\ngauge theory is expressed as operators acting on qubits. The number of\nindependent gauge links is reduced to its minimum through the use of Gauss's\nlaw. The model can be implemented with any number of qubits per gauge link, and\na choice as small as two is shown to be useful. Real-time propagation and\nreal-time collisions are observed on lattices in two spatial dimensions. The\nextension to three spatial dimensions is also developed, and a first look at\n3-dimensional real-time dynamics is presented."
    },
    {
        "anchor": "B Meson Decay Constants Using NRQCD: Recent results for B meson decay constants with NRQCD b-quarks and clover\nlight quarks are discussed. Perturbative matching factors through O($\\alpha/M$)\nare now available and incorporated into the analyses. An O($\\alpha a$)\nimprovement term to the heavy-light axial current is identified and included.\nThe slope of $f_{PS}\\sqrt{M_{PS}}$ versus $1/M_{PS}$ is significantly reduced\nby these corrections.",
        "positive": "Confining vs. conformal scenario for SU(2) with adjoint fermions.\n  Gluonic observables: Walking technicolor is a mechanism for electroweak symmetry breaking without\nHiggs field. The Higgs mechanism is provided by chiral symmetry breaking in the\ntechnicolor theory. An essential ingredient is the vicinity to an IR fixed\npoint, which could reconcile technicolor with the electroweak precision tests.\nSU(2) gauge theory with two Dirac adjoint fermions has been proposed as a\ncandidate for walking technicolor. Understanding whether this theory is\nconfining or IR-conformal is a challenging problem, which can be addressed by\nmeans of numerical simulations. We have pointed out that a clean signal for the\nexistence of an IR fixed point in this theory can be obtained by comparing the\nmesonic and gluonic sectors. We review some technical details of our\ncalculations. Possible systematic errors are discussed."
    },
    {
        "anchor": "The Compton amplitude and nucleon structure functions in lattice QCD: The structure of hadrons relevant for deep-inelastic scattering are\ncompletely characterised by the Compton amplitude. A direct calculation of the\nCompton amplitude in a lattice QCD setup provides a way to accessing the\nstructure functions, circumventing the operator mixing and renormalisation\nissues of the standard operator product expansion approach. In this\ncontribution, we focus on the QCDSF/UKQCD Collaboration's advances in\ncalculating the forward Compton amplitude via an implementation of the\nsecond-order Feynman-Hellmann theorem. We highlight our progress in\ninvestigating the moments of nucleon structure functions.",
        "positive": "The Phase Diagram of a U(1) Higgs-Yukawa Model at Finite $\u03bb$: In this paper we investigate how the phase diagram of a U(1) symmetric\nHiggs-Yukawa system depends on the scalar self coupling $\\lambda$. The phase\ndiagram of similar models with continuous symmetry were extensively studied in\nthe infinite scalar self coupling $\\lambda=\\infty$ limit. Recent analytical and\nnumerical calculations at zero self coupling showed qualitatively different\nphase diagram, raising the question of the $\\lambda$ dependence of the phase\ndiagram. Here we use analytical (large $N_f$, perturbative and mean field)\napproximations as well as numerical simulations to investigate the system."
    },
    {
        "anchor": "Pion and Kaon Distribution Amplitudes in the Continuum Limit: We present a lattice-QCD calculation of the pion, kaon and $\\eta_s$\ndistribution amplitudes using large-momentum effective theory (LaMET). Our\ncalculation is carried out using three ensembles with 2+1+1 flavors of highly\nimproved staggered quarks (HISQ), generated by MILC collaboration, at 310 MeV\npion mass with 0.06, 0.09 and 0.12 fm lattice spacings. We use clover fermion\naction for the valence quarks and tune the quark mass to match the lightest\nlight and strange masses in the sea. The resulting lattice matrix elements are\nnonperturbatively renormalized in regularization-independent\nmomentum-subtraction (RI/MOM) scheme and extrapolated to the continuum. We use\ntwo approaches to extract the $x$-dependence of the meson distribution\namplitudes: 1) we fit the renormalized matrix elements in coordinate space to\nan assumed distribution form through a one-loop matching kernel; 2) we use a\nmachine-learning algorithm trained on pseudo lattice-QCD data to make\npredictions on the lattice data. We found the results are consistent between\nthese methods with the latter method giving a less smooth shape. Both\napproaches suggest that as the quark mass increases, the distribution amplitude\nbecomes narrower. Our pion distribution amplitude has broader distribution than\npredicted by light-front constituent-quark model, and the moments of our pion\ndistributions agree with previous lattice-QCD results using the operator\nproduction expansion.",
        "positive": "Baryon Number, Strangeness and Electric Charge Fluctuations in QCD at\n  High Temperature: We analyze baryon number, strangeness and electric charge fluctuations as\nwell as their correlations in QCD at high temperature. We present results\nobtained from lattice calculations performed with an improved staggered fermion\naction (p4-action) at two values of the lattice cut-off with almost physical up\nand down quark masses and a physical value for the strange quark mass. We\ncompare these results, with an ideal quark gas at high temperature and a hadron\nresonance gas model at low temperature. We find that fluctuations and\ncorrelations are well described by the former already for temperatures about\n1.5 times the transition temperature. At low temperature qualitative features\nof the lattice results are quite well described by a hadron resonance gas\nmodel. Higher order cumulants, which become increasingly sensitive to the light\npions, however show deviations from a resonance gas in the vicinity of the\ntransition temperature."
    },
    {
        "anchor": "Quark-gluon vertex from Nf=2 lattice QCD: We study the quark-gluon vertex in the limit of vanishing gluon momentum\nusing lattice QCD with 2 flavors of O(a) improved Wilson fermions, for several\nlattice spacings and quark masses. We find that all three form factors in this\nkinematics have a significant infrared strength, and that both the leading form\nfactor $\\lambda_1$, multiplying the tree-level vertex structure, and the\nscalar, chiral symmetry breaking form factor $\\lambda_3$ are significantly\nenhanced in the infrared compared to the quenched (Nf=0) case. These\nenhancements are orders of magnitude larger than predicted by one-loop\nperturbation theory. We find only a weak dependence on the lattice spacing and\nquark mass.",
        "positive": "Two Color QCD beyond the BEC regime: We present results of simulations of Two Color QCD using two flavors of\nWilson quark in the fundamental representation, at non-zero quark chemical\npotential mu, on an 8^3x16 lattice. Results for the quark number density, quark\nand gluon energy densities, and superfluid condensate are qualitatively\ndistinct from the behaviour expected on the assumption that the dominant\ndegrees of freedom are tightly bound scalar diquarks which Bose condense;\nrather the scaling with mu is more suggestive of a Fermi surface disrupted by a\nCooper pair condensate. We also present evidence both for screening of the\nstatic potential, and color deconfinement, arising solely as a result of a\nnon-zero quark density."
    },
    {
        "anchor": "Surface width of the Solid-On-Solid models: The low-temperature series for the surface width of the Absolute value\nSolid-On-Solid model and the Discrete Gaussian model both on the square lattice\nand on the triangular lattice are generated to high orders using the improved\nfinite-lattice method. The series are analyzed to give the critical points of\nthe roughening phase transition for each model.",
        "positive": "Multi-Quarks and Two-Baryon Interaction in Lattice QCD: We study multi-quark (3Q,4Q,5Q) systems in lattice QCD. We perform the\ndetailed studies of multi-quark potentials in lattice QCD to clarify the\ninter-quark interaction in multi-quark systems. We find that all the\nmulti-quark potentials are well described by the OGE Coulomb plus multi-Y-type\nlinear potential, i.e., the multi-Y Ansatz. For multi-quark systems, we observe\nlattice QCD evidences of ``flip-flop'', i.e., flux-tube recombination. These\nlattice QCD studies give an important bridge between elementary particle\nphysics and nuclear physics."
    },
    {
        "anchor": "Observations on staggered fermions at non-zero lattice spacing: We show that the use of the fourth-root trick in lattice QCD with staggered\nfermions corresponds to a non-local theory at non-zero lattice spacing, but\nargue that the non-local behavior is likely to go away in the continuum limit.\nWe give examples of this non-local behavior in the free theory, and for the\ncase of a fixed topologically non-trivial background gauge field. In both\nspecial cases, the non-local behavior indeed disappears in the continuum limit.\nOur results invalidate a recent claim that at non-zero lattice spacing an\nadditive mass renormalization is needed because of taste-symmetry breaking.",
        "positive": "The QCD phase diagram from analytic continuation: We present the crossover line between the quark gluon plasma and the hadron\ngas phases for small real chemical potentials. First we determine the effect of\nimaginary values of the chemical potential on the transition temperature using\nlattice QCD simulations. Then we use various formulas to perform an analytic\ncontinuation to real values of the baryo-chemical potential. Our data set\nmaintains strangeness neutrality to match the conditions of heavy ion physics.\nThe systematic errors are under control up to $\\mu_B\\approx 300$ MeV. For the\ncurvature of the transition line we find that there is an approximate agreement\nbetween values from three different observables: the chiral susceptibility,\nchiral condensate and strange quark susceptibility. The continuum extrapolation\nis based on $N_t=$ 10, 12 and 16 lattices. By combining the analysis for these\nthree observables we find, for the curvature, the value $\\kappa = 0.0149 \\pm\n0.0021$."
    },
    {
        "anchor": "First order transition regions in the quark masses and chemical\n  potential parameter space of QCD: We investigate the phase transitions of (2+Nf)-flavor QCD, where two light\nflavors and Nf massive flavors exist, aiming to understand the phase structure\nof (2+1)-flavor QCD. Performing simulations of 2-flavor QCD with improved\nstaggered and Wilson fermions and using the reweighting method, we calculate\nprobability distribution functions in the many-flavor QCD. Through the shape of\ndistribution functions, we determine the critical surface terminating first\norder phase transitions in the parameter space of the light quark mass, heavy\nquark mass and the chemical potential, and find that the first order region\nbecomes larger with Nf. We then study the critical surface at finite density\nfor large Nf and the first order region is found to become wider with the\nincreasing chemical potential. On the other hand, the light quark mass\ndependence of the critical mass of heavy quarks seems weak in the region we\ninvestigated. The result of this weak dependence suggests that the critical\nmass of heavy quark remains finite in the chiral limit of 2-flavors and there\nexists a second order transition region on the line of the 2-flavor massless\nlimit above the tri-critical point. Moreover, we extend the study of 2-flavor\nQCD at finite density to the case of a complex chemical potential and\ninvestigate the singularities where the partition function vanishes, so-called\nLee-Yang zeros. The plaquette effective potential is computed in the complex\nplane. We find that the shape of the effective potential changes from\nsingle-well on the real axis to double-well at large imaginary chemical\npotential and the double-well potential causes the singularities.",
        "positive": "Non-Hermitian Polynomial Hybrid Monte Carlo: We report on a new variant of the hybrid Monte Carlo algorithm employing a\npolynomial approximation of the inverse of the non-Hermitian Dirac-Wilson\noperator. Our approximation relies on simple and stable recurrence relations of\ncomplex Chebyshev polynomials. First performance figures are presented."
    },
    {
        "anchor": "Baryon-baryon interaction of strangeness S=-1 sector: We present our recent studies on hyperon-nucleon (YN) interactions in the\nstrangeness S=-1 that $p\\Lambda, \\Sigma^0 p$ and $\\Sigma^+ n$, by extracting\ncorresponding potentials through Nambu-Bethe-Salpeter wave functions. We\ncalculate $\\Lambda N$ and $\\Sigma N$ potentials in the isospin I=3/2 channel,\nusing the $N_f=2+1$ gauge configurations generated by PACS-CS collaboration and\nemploying an improved method to obtain potentials in lattice QCD simulations.\nFor the $^1S_0$ channel, the central $\\Sigma N (I=3/2, ^1S_0)$ potential and\nthe central $\\Lambda N (^1S_0)$ potential are found to be very similar. In the\nspin triplet ($^3S_1-^3D_1$) channels, the central $\\Lambda N(^3S_1-^3D_1)$\npotential is attractive while the central $\\Sigma N(I=3/2, ^3S_1-^3D_1)$\npotentials is repulsive. Tensor potentials, on the other hand, are rather weak\nin the diagonal part of both $\\Lambda N$ and $\\Sigma N(I=3/2)$ systems.",
        "positive": "Trace anomaly form factors from lattice QCD: The hadron mass can be obtained through the calculation of the trace of the\nenergy momentum tensor (EMT) in the hadron which includes the trace anomaly and\nsigma terms. The anomaly due to the conformal symmetry breaking is believed to\nbe an important ingredient for hadron mass generation and confinement. In this\nwork, we will present the calculation of the glue part of the trace anomaly\nform factors of the pion up to $Q^2\\sim 4.3~\\mathrm{GeV}^2$ and the nucleon up\nto $Q^2\\sim 1~\\mathrm{GeV}^2$. The calculations are performed on a domain wall\nfermion (DWF) ensemble with overlap valence quarks at 7 valence pion masses\nvarying from $\\sim 250~\\mathrm{MeV}$ to $\\sim 540~\\mathrm{MeV}$, including the\nunitary point $\\sim 340$ MeV. We calculate the radius of the glue trace anomaly\nfor the pion and the nucleon from the $z$-expansion. By performing a\ntwo-dimensional Fourier transform on the glue trace anomaly form factors in the\ninfinite momentum frame with no energy transfer, we also obtain their spatial\ndistributions for several valence quark masses. The results are extrapolated to\nthe physical pion mass. We find the pion's form factor changes sign, as does\nits spatial distribution, for light quark masses. This explains how the trace\nanomaly contribution to the pion mass approaches zero toward the chiral limit."
    },
    {
        "anchor": "Two-point Correlator Fits on HISQ Ensembles: We present our methods to fit the two point correlators for light, strange,\nand charmed pseudoscalar meson physics with the highly improved staggered quark\n(HISQ) action. We make use of the least-squares fit including the full\ncovariance matrix of the correlators and including Gaussian constraints on some\nparameters. We fit the correlators on a variety of the HISQ ensembles. The\nlattice spacing ranges from 0.15 fm down to 0.06 fm. The light sea quark mass\nranges from 0.2 times the strange quark mass down to the physical light quark\nmass. The HISQ ensembles also include lattices with different volumes and with\nunphysical values of the strange quark mass. We use the results from this work\nto obtain our preliminary results of $f_D$, $f_{D_s}$, $f_{D_s}/f_{D}$, and\nratios of quark masses presented in another talk [1].",
        "positive": "Determination of F_pi from Distributions of Dirac Operator Eigenvalues\n  with Imaginary Density: In the epsilon-regime of lattice QCD one can get an accurate measurement of\nthe pion decay constant F_pi by monitoring how just one single Dirac operator\neigenvalue splits into two when subjected to two different external vector\nsources. Because we choose imaginary chemical potentials our Dirac eigenvalues\nremain real. Based on the relevant chiral Random Two-Matrix Theory we derive\nindividual eigenvalue distributions in terms of density correlations functions\nto leading order in the finite-volume epsilon-expansion. As a simple byproduct\nwe also show how the associated individual Dirac eigenvalue distributions and\ntheir correlations can be computed directly from the effective chiral\nLagrangian."
    },
    {
        "anchor": "Lattice gradient flow with tree-level $\\mathcal{O}(a^4)$ improvement in\n  pure Yang-Mills theory: Following a recent paper by Fodor et al. (arXiv:1406.0827), we reexamine\nseveral types of tree-level improvements on the flow action with various gauge\nactions in order to reduce the lattice discretization errors in the Yang-Mills\ngradient flow method. We propose two types of tree-level, $\\mathcal{O}(a^4)$\nimproved lattice gradient flow including the rectangle term in both the flow\nand gauge action within the minimal way. We then perform numerical simulations\nwith the simple plaquette gauge action for testing our proposal. Our numerical\nresults of the expectation value of the action density, $\\langle E(t)\\rangle$,\nshow that two $\\mathcal{O}(a^4)$ improved flows significantly eliminate the\ndiscretization corrections in the small flow time $t$ regime. On the other\nhand, the values of $t^2\\langle E(t)\\rangle$ in the large $t$ regime, where the\nlattice spacing dependence of the tree-level term dies out as inverse powers of\n$t/a^2$, are different between the results given by two optimal flows leading\nto the same $\\mathcal{O}(a^4)$ improvement at tree level. This may suggest that\nnon-negligible $\\mathcal{O}(g^2 a^2)$ effect sets in the large $t$ regime,\nwhere the running coupling $g(1/\\sqrt{8t})$ becomes large.",
        "positive": "Universality and Quark Masses of the Staggered Fermion Action: Staggered fermions with 4 tastes are expected to describe 4-flavor QCD in the\ncontinuum limit, therefore at finite lattice spacing the staggered determinant\nshould be equivalent to an SU(4) flavor-symmetric system up to lattice\nartifacts. This equivalence is the starting point of the 4th root trick used to\nreduce the number of fermion flavors and provides the only consistent\ndescription of 2 or 1 flavor systems. In this paper we argue that the quark\nmass of the underlying flavor symmetric theory differs from the staggered mass\nby an additive term due to the taste breaking of the staggered action. The\nrelation is the same for 2 and 1 flavor fermions. This additive mass shift\nimplies that at finite lattice spacing staggered simulations correspond to\nheavier quark masses than indicated by the staggered Goldstone pion and that\nstaggered fermions cannot reach the chiral limit at finite lattice spacing."
    },
    {
        "anchor": "Empirical Baye's Method and Test in Very Light Quark Range from The\n  Overlap Lattice QCD: Based on Bayesian theorem an empirical Baye's method is discussed. A\nprogramming chart for mass spectrum fitting is suggested. A weakly constrained\nway for getting priors to solve the chiral log data fitting singularity is\ntested.",
        "positive": "DIS Structure Functions in Lattice QCD: In this talk I present the complete 1-loop perturbative computation of the\nrenormalization constants and mixing coefficients of quark and gluon lattice\noperators of rank two and three whose hadronic elements enter in the\ndetermination of the first and second moment of Deep Inelastic Scattering\nStructure Functions, making use of the nearest-neighbor improved\n``clover-leaf'' lattice QCD action.\n  To perform the huge amount of calculations required for the evaluation of all\nthe relevant Feynman diagrams, extensive use of symbolic manipulation languages\nlike Schoonschip and Form has been made."
    },
    {
        "anchor": "The Polyakov Loop and the Eigenvalues of the Dirac Operator: Aiming at the link between confinement and chiral symmetry the Polyakov loop\nrepresented as a spectral sum of eigenvalues of the Dirac operator was subject\nof recent studies. We analyze the volume dependence as well as the continuum\nbehavior of this quantity for quenched QCD using staggered fermions.\nFurthermore, we present first results using dynamical configurations.",
        "positive": "Decays of mesons with charm quarks on the lattice: We investigate mesons containing charm quarks on fine lattices with a^{-1}\n\\sim 5 GeV. The quenched approximation is employed using the Wilson gauge\naction at \\beta = 6.6 and nonperturbatively O(a) improved Wilson quarks. We\npresent results for decay constants using various interpolating fields and give\npreliminary results for form factors of semileptonic decays of D_s mesons to\nlight pseudoscalar mesons."
    },
    {
        "anchor": "Test of the Skyrme Effective Field Theory Using Quenched Lattice QCD: The Skyrme effective field theory is tested by evaluating nucleon ground\nstate matrix elements of the correlation functions for two flavor density\noperators and two pseudoscalar density operators in the Skyrme model and\ncomparing them with results in quenched lattice QCD. The possiblility of using\nquenched lattice QCD to study higher-order terms in effective field theory is\nalso discussed.",
        "positive": "Staggered Lattice Artifacts in 3-Flavor Heavy Baryon Chiral Perturbation\n  Theory: Motivated by simulation results for octet and decuplet baryon masses using\n2+1 flavors of light staggered quarks, we are incorporating staggered lattice\nartifacts into heavy baryon chiral perturbation theory, calculating the masses\nof various staggered baryons, and studying the connection between the staggered\nbaryons of the chiral theory and the staggered baryons of simulations. We\npresent order (m_q)^(3/2) loop contributions to the masses of several staggered\nnucleons and discuss interpolating fields that create these states."
    },
    {
        "anchor": "Exploratory Lattice QCD Study of the Rare Kaon Decay\n  $K^+\\to\u03c0^+\u03bd\\bar\u03bd$: We report a first, complete lattice QCD calculation of the long-distance\ncontribution to the $K^+\\to\\pi^+\\nu\\bar{\\nu}$ decay within the standard model.\nThis is a second-order weak process involving two four-Fermi operators that is\nhighly sensitive to new physics and being studied by the NA62 experiment at\nCERN. While much of this decay comes from perturbative, short-distance physics\nthere is a long-distance part, perhaps as large as the planned experimental\nerror, which involves nonperturbative phenomena. The calculation presented\nhere, with unphysical quark masses, demonstrates that this contribution can be\ncomputed using lattice methods by overcoming three technical difficulties: (i)\na short-distance divergence that results when the two weak operators approach\neach other, (ii) exponentially growing, unphysical terms that appear in\nEuclidean, second-order perturbation theory, and (iii) potentially large\nfinite-volume effects. A follow-on calculation with physical quark masses and\ncontrolled systematic errors will be possible with the next generation of\ncomputers.",
        "positive": "Partial quenching and chiral symmetry breaking: Partially quenched chiral perturbation theory assumes that valence quarks\npropagating on gauge configurations prepared with sea quarks of different\nmasses will form a chiral condensate as the valence quark mass goes to zero. I\npresent a counterexample involving non-degenerate sea quarks where the valence\ncondensate does not form."
    },
    {
        "anchor": "On the Landau Ginzburg theory of MAG projected SU(2) lattice gauge\n  theory: Maximal Abelian gauge fixing and subsequent Abelian projection of SU(2)\nlattice gauge theory defines closed trajectories of magnetic monopoles. These\ntrajectories can be interpreted in terms of an effective scalar field theory of\nthe MAG monopoles using the worldline representation of the functional\ndeterminants. Employing the monopole worldlines detected in the numerical\nsimulation, we show that a scalar bound state exists. The screening mass $m$ of\nthis state properly scales towards the continuum limit. We find m ~ 1.3 $GeV\nwhen the string tension sigma = 440 MeV is used as reference scale.",
        "positive": "Nucleon isovector form factors from physical-mass 2+1-flavor dynamical\n  domain-wall QCD: The current status is reported of joint lattice numerical calculations by LHP\nand RBC collaborations of isovector nucleon form factors using 2+1-flavor\nphysical-mass domain-wall fermions ensemble at a lattice cutoff $a^{-1}$ of\n1.730(4) GeV and spatial volume of $(La=\\mbox{\\rm 5.471(13)fm})^3$ generated\njointly by RBC and UKQCD collaborations."
    },
    {
        "anchor": "'t Hooft vertices, partial quenching, and rooted staggered QCD: We discuss the properties of 't Hooft vertices in partially quenched and\nrooted versions of QCD in the continuum. These theories have a physical\nsubspace, equivalent to ordinary QCD, that is contained within a larger space\nthat includes many unphysical correlation functions. We find that the 't Hooft\nvertices in the physical subspace have the expected form, despite the presence\nof unphysical 't Hooft vertices appearing in correlation functions that have an\nexcess of valence quarks (or ghost quarks). We resolve an apparent paradox that\narises when one uses rooted staggered fermions to study one-flavor QCD, by\nshowing how, in partially quenched theories, it is possible to have spontaneous\nsymmetry breaking of a non-anomalous symmetry in finite volume. Using these\nresults, we demonstrate that arguments recently given by Creutz--claiming to\ndisprove the validity of rooted staggered QCD--are incorrect. In particular,\nthe unphysical 't Hooft vertices do not present an obstacle to the recovery of\ntaste symmetry in the continuum limit.",
        "positive": "Infrared fixed point of the 12-fermion SU(3) gauge model based on\n  2-lattice MCRG matching: I investigate an SU(3) gauge model with 12 fundamental fermions. The\nphysically interesting region of this strongly coupled system can be influenced\nby an ultraviolet fixed point due to lattice artifacts. I suggest to use a\ngauge action with an additional negative adjoint plaquette term that lessens\nthis problem. I also introduce a new analysis method for the 2-lattice matching\nMonte Carlo renormalization group technique that significantly reduces finite\nvolume effects. The combination of these two improvements allows me to measure\nthe bare step scaling function in a region of the gauge coupling where it is\nclearly negative, indicating a positive renormalization group $\\beta$ function\nand infrared conformality."
    },
    {
        "anchor": "Scattering phaseshift formulas for mesons and baryons in elongated boxes: We derive L\\\"{u}scher phaseshift formulas for two-particle states in boxes\nelongated in one of the dimensions. Such boxes offer a cost-effective way of\nvarying the relative momentum of the particles. Boosted states in the elongated\ndirection, which allow wider access to energies, are also considered. The\nformulas for the various scenarios (moving and zero-momentum states in cubic\nand elongated boxes) are compared and relations between them are clarified. The\nresults are applicable to a wide set of meson-meson and meson-baryon elastic\nscattering processes, with the two-particle system having equal or unequal\nmasses.",
        "positive": "Fast algorithms for simulating chiral fermions in U(1)lattice gauge\n  theory: In order to develop fast inversion algorithms we have used overlap solvers in\ntwo dimensions. Lattice QED theory with U(1) group symmetry in two dimensional\nspace-times dimensions has always been a testing ground for algorithms. By the\nother side, motivated by our previews work that the two-grid algorithm converge\nfaster than the standard iterative methods for overlap inversion but not for\nall quark masses, we thought to test this idea in less dimensions such as U(1)\ngauge theory. Our main objective of this paper it is to implement and develop\nthe idea of a two level algorithm in a new algorithm coded in QCDLAB. This\nimplementation is presented in the preconditioned GMRESR algorithm, as our new\ncontribution in QCDLAB package. The preconditioned part of our algorithm,\ndifferent from the one of [18], is the approximation of the overlap operator\nwith the truncated overlap operator with finite N3 dimension. We have tested it\nfor 100 statistically independent configurations on 32 x 32 lattice background\nU(1) field at coupling constant \\b{eta}=1 and for different bare quark masses\nmq = [0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1]. We have compared the\nconvergence history of the preconditioned GMRESR residual norm with another\noverlap inverter of QCDLAB as an optimal one, such as SHUMR. We have shown that\nour algorithm converges faster than SHUMR for different quark masses. Also, we\nhave demonstrated that it saves more time for light quarks compared to SHUMR\nalgorithm. Our algorithm is approximately independent from the quark mass. This\nis a key result in simulations with chiral fermions in lattice theories. By the\nother side, if we compare the results of [18] for quark mass 0.1 in SU(3),\nresults that our chosen preconditioned saves a factor of 2 but in U(1). Our\nnext step is to test this algorithm in SU(3) and to adopt it in parallel."
    },
    {
        "anchor": "SU(2) Flux Distributions on Finite Lattices: We studied SU(2) flux distributions on four dimensional euclidean lattices\nwith one dimension very large. By choosing the time direction appropriately we\ncan study physics in two cases: one is finite volume in the zero temperature\nlimit, another is finite temperature in the the intermediate to large volume\nlimit. We found that for cases of beta > beta crit there is no intrinsic string\nformation. Our lattices with beta > beta crit belong to intermediate volume\nregion, and the string tension in this region is due to finite volume effects.\nIn large volumes we found evidence for intrinsic string formation.",
        "positive": "The nature of the thermal phase transition with Wilson quarks: We describe a series of simulations of high temperature QCD with two flavors\nof Wilson quarks aimed at clarifying the nature of the high temperature phase\nfound in current simulations. Most of our work is with four time slices,\nalthough we include some runs with six and eight time slices for comparison. In\naddition to the usual thermodynamic observables we study the quark mass defined\nby the divergence of the axial current and the quark propagator in the Landau\ngauge. We find that the sharpness of the $N_t=4$ thermal transition has a\nmaximum around $\\kappa=0.19$ and $6/g^2=4.8$."
    },
    {
        "anchor": "Search for H dibaryon on the lattice: We investigate the H-dibaryon, an $I(J^{P})=0(0^{+})$ with $s=-2$, in the\nchiral and continuum regimes on anisotropic lattices in quenched QCD.\nSimulations are performed on very coarse lattices with refined techniques to\nobtain results with high accuracy over a spatial lattice spacing in the range\nof $a_{s} \\sim 0.19 - 0.41$ fm. We present results for the energy difference\nbetween the ground state energy of the hexa-quark stranglet and the free\ntwo-baryon state from our ensembles. A negative binding energy observed in the\nchirally extrapolated results leads to the conclusion that the measured\nhexa-quark state is bound. This is further confirmed by the attractive\ninteraction in the continuum limit with the observed H-dibaryon bound by $\\sim\n47$ MeV.",
        "positive": "Finite Temperature Spacelike Gluon Propagators in Lattice Momentum Space: We study the behaviour of lattice momentum-space gluon propagators for a pure\n$SU(2)$ gauge theory at finite temperature. We find out that the magnetic mass\nis $0.26 g^2(T) T$; we have repeated the same calculations in three dimensions."
    },
    {
        "anchor": "Further results on O(a) improved lattice QCD to one-loop order of\n  perturbation theory: We present results at one-loop order of perturbation theory for various\nimprovement coefficients in on-shell O($a$) improved lattice QCD. In particular\nwe determine the additive counterterm required for on-shell improvement of the\nisovector vector current. Employing a general mass-independent renormalization\nscheme we also obtain the coefficients of the O($a$) counterterms which are\nproportional to the quark mass in the improved isovector pseudo-scalar, axial\nvector and vector operators. In the latter case a comparison with a recent\nnon-perturbative study is made.",
        "positive": "Topological Summation in Lattice Gauge Theory: In gauge theories the field configurations often occur in distinct\ntopological sectors. In a lattice regularised system with chiral fermions,\nthese sectors can be defined by referring to the Atiyah-Singer Index Theorem.\nHowever, if such a model is simulated with local updates of the lattice gauge\nconfiguration, the Monte Carlo history tends to get stuck in one sector for\nmany steps, in particular on fine lattices. Then expectation values can be\nmeasured only within specific sectors. Here we present a pilot study in the\n2-flavour Schwinger model which explores methods of approximating the complete\nresult for an observable - corresponding to a suitable sum over all sectors -\nbased on numerical measurements in a few specific topological sectors. We also\nprobe various procedures for an indirect evaluation of the topological\nsusceptibility, starting from such topologically restricted measurements."
    },
    {
        "anchor": "$O(4)$-symmetric position-space renormalization of lattice operators: We extend the position-space renormalization procedure, where renormalization\nfactors are calculated from Green's functions in position space, by introducing\na technique to take the average of Green's functions over spheres. In addition\nto reducing discretization errors, this technique enables the resulting\nposition-space correlators to be evaluated at any physical distance, making\nthem continuous functions similar to the $O(4)$-symmetric position-space\nGreen's functions in the continuum theory but with a residual dependence on a\nregularization parameter, the lattice spacing $a$. We can then take the\ncontinuum limit of these renormalized quantities calculated at the same\nphysical renormalization scale $|x|$ and investigate the resulting\n$|x|$-dependence to identify the appropriate renormalization window.\n  As a numerical test of the spherical averaging technique, we determine the\nrenormalized light and strange quark masses by renormalizing the scalar\ncurrent. We see a substantial reduction of discretization effects on the scalar\ncurrent correlator and an enhancement of the renormalization window. The\nnumerical simulation is carried out with $2+1$-flavor domain-wall fermions at\nthree lattice cutoffs in the range 1.79--3.15~GeV.",
        "positive": "Singularities of the Partition Function for the Ising Model Coupled to\n  2d Quantum Gravity: We study the zeros in the complex plane of the partition function for the\nIsing model coupled to 2d quantum gravity for complex magnetic field and real\ntemperature, and for complex temperature and real magnetic field, respectively.\nWe compute the zeros by using the exact solution coming from a two matrix model\nand by Monte Carlo simulations of Ising spins on dynamical triangulations. We\npresent evidence that the zeros form simple one-dimensional curves in the\ncomplex plane, and that the critical behaviour of the system is governed by the\nscaling of the distribution of the singularities near the critical point.\nDespite the small size of the systems studied, we can obtain a reasonable\nestimate of the (known) critical exponents."
    },
    {
        "anchor": "Improved Error Estimate for the Valence Approximation: We construct a systematic mean-field-improved coupling constant and quark\nloop expansion for corrections to the valence (quenched) approximation to\nvacuum expectation values in the lattice formulation of QCD. Terms in the\nexpansion are evaluated by a combination of weak coupling perturbation theory\nand a Monte Carlo algorithm.",
        "positive": "Heavy quark diffusion coefficient with gradient flow: The heavy quark diffusion coefficient is encoded in the spectral functions of\nthe chromo-electric and the chromo-magnetic correlators, of which the latter\ndescribes the T/M contribution. We study these correlators at two different\ntemperatures $T=1.5T_c$ and $T=10^4T_c$ in the deconfined phase of SU(3) gauge\ntheory. We use gradient flow for noise reduction. We perform both continuum and\nzero flow time limits to extract the heavy quark diffusion coefficient. Our\nresults imply that the mass suppressed effects in the heavy quark diffusion\ncoefficient are 20% for bottom quarks and 34% for charm quark at $T=1.5T_c$."
    },
    {
        "anchor": "The D234 action for light quarks: We investigate a new light fermion action (the ``D234'' action), which is\naccurate up to $\\O(a^3)$ and tadpole-improved $\\O(a \\alpha_s)$ errors. Using\nD234 with Symanzik- and tadpole-improved glue we find evidence that continuum\nresults for the quenched hadron spectrum (pion, rho and nucleon) can be\nobtained on coarse lattices.",
        "positive": "Hadron Interactions from lattice QCD: We review our strategy to study hadron interactions from lattice QCD using\nnewly proposed potential method. We first explain our strategy in the case of\nnuclear potentials and its application to nuclear physics. We then discuss the\norigin of the repulsive core, by adding strange quarks to the system. We also\nexplore a possibility for H-dibaryon to exist in flavor SU(3) limit of lattice\nQCD. We conclude the paper with an application of our strategy to investigate\nthe maximum mass of neutron stars."
    },
    {
        "anchor": "The melting and abundance of open charm hadrons: Ratios of cumulants of conserved net charge fluctuations are sensitive to the\ndegrees of freedom that are carriers of the corresponding quantum numbers in\ndifferent phases of strong interaction matter. Using lattice QCD with 2+1\ndynamical flavors and quenched charm quarks we calculate second and fourth\norder cumulants of net charm fluctuations and their correlations with other\nconserved charges such as net baryon number, electric charge and strangeness.\nAnalyzing appropriate ratios of these cumulants we probe the nature of charmed\ndegrees of freedom in the vicinity of the QCD chiral crossover region. We show\nthat for temperatures above the chiral crossover transition temperature,\ncharmed degrees of freedom can no longer be described by an uncorrelated gas of\nhadrons. This suggests that the dissociation of open charm hadrons and the\nemergence of deconfined charm states sets in just near the chiral crossover\ntransition. Till the crossover region we compare these lattice QCD results with\ntwo hadron resonance gas models --including only the experimentally established\ncharmed resonances and also including additional states predicted by quark\nmodel and lattice QCD calculations. This comparison provides evidence for so\nfar unobserved charmed hadrons that contribute to the thermodynamics in the\ncrossover region.",
        "positive": "An Analytic Study of the Phase Structure of Lattice QCD with Wilson\n  Fermions at Infinitely Strong Coupling: The phase structure of lattice QCD with two flavors and Wilson fermions is\nstudied analytically. At $\\beta=0$ we obtain rigorous lower and upper bounds\nfor the critical hopping parameter $k_c(0)$ from a convergent hopping parameter\nexpansion to infinite order. The result supports the value $k_c(0)=\\frac{1}{4}$\nobserved in Monte Carlo simulations."
    },
    {
        "anchor": "QCD topology and axion's properties from Wilson twisted mass lattice\n  simulations: We present the results on topological susceptibility and chiral observables\nin $N_f=2+1+1$ QCD for temperature range $120<T<600$ MeV. The lattice\nsimulations are performed with Wilson twisted mass fermions at physical pion,\nstrange and charm masses. In high-$T$ region $T\\gtrsim 300$ MeV the chiral\nobservables are shown to follow leading order Griffith analyticity, and the\ntopological susceptibility follows a power-law decay as in the instanton dilute\ngas models. The measured topological susceptibility is used to estimate the\nmass of QCD axion. The resulting axion mass constraints are in agreement with\nour previous studies at higher pion masses.",
        "positive": "Towards a theoretical description of dense QCD: The properties of matter at finite baryon densities play an important role\nfor the astrophysics of compact stars as well as for heavy ion collisions or\nthe description of nuclear matter. Because of the sign problem of the quark\ndeterminant, lattice QCD cannot be simulated by standard Monte Carlo at finite\nbaryon densities. I review alternative attempts to treat dense QCD with an\neffective lattice theory derived by analytic strong coupling and hopping\nexpansions, which close to the continuum is valid for heavy quarks only, but\nshows all qualitative features of nuclear physics emerging from QCD. In\nparticular, the nuclear liquid gas transition and an equation of state for\nbaryons can be calculated directly from QCD. A second effective theory based on\nstrong coupling methods permits studies of the phase diagram in the chiral\nlimit on coarse lattices."
    },
    {
        "anchor": "The overlooked significance of the unbiased exponential phasefactor in\n  the determination of the finite-density lattice QCD equation of state: Within the framework of (2+1)-flavor QCD at finite temperature and chemical\npotential, we present results using high statistics data and demonstrate how\nthe phasefactor of low order unbiased exponential resummation offers excellent\nprediction, proving to be an alternative reliable estimator of the radius of\nconvergence of the eighth order QCD Taylor series at finite baryon density\nmeasured using the ratio and the Merci-Roberts estimators. We construct a new\nnon-trivial unbiased phasefactor for complex isospin chemical potentials $\\muI$\nand highlight its novelty. We find that this new unbiased phasefactor is very\nmuch capable of indicating the onset of non-monotonicity in finite $\\muI$\nthermodynamics, which we illustrate by comparing the phasefactor results with\nthat of low order cumulants of $\\muI$ fluctuations for non-vanishing $\\muI$. We\nalso furnish results establishing that this unbiased phasefactor is reliable in\nmanifesting the beginning of the overlap problem for finite, real $\\muI$. The\nerrorbars increase drastically across the indications provided by the\nphasefactor which becomes very apparent from the coincidence between the\nphasefactor and the maximum of the errorbar slopes.",
        "positive": "Twelve fundamental and two sextet fermion flavors: We report extended simulation results and their new analysis in two important\ngauge theories with twelve fermion flavors in the fundamental SU(3) color\nrepresentation and two fermions in the sextet representation. We probe the\n$N_f=12$ model with respect to the conformal window using mass deformed finite\nsize scaling (FSS) theory driven by the fermion mass anomalous dimension. Our\nresults at fixed gauge coupling show problems with the conformal scenario of\nthe $N_f=12$ model. In the sextet model with two flavors, under the conformal\nhypothesis, we determine large values for the anomalous fermion mass dimension\nwith $\\gamma\\geq 1$. Since our sextet analysis favors the chiral symmetry\nbreaking hypothesis without conformality, the large exponent $\\gamma$ could\nplay an important role in understanding the composite Higgs mechanism. The new\nresults discussed here include our extended data sets and exceed what was\npresented at the conference."
    },
    {
        "anchor": "Progress Report on Computing Excited-State Hadron Masses in Lattice QCD: Our progress in computing the spectrum of excited baryons and mesons in\nlattice QCD is described. Sets of spatially-extended hadron operators with a\nvariety of different momenta are used. A new method of stochastically\nestimating the low-lying effects of quark propagation is utilized which allows\nreliable determinations of temporal correlations of both single-hadron and\nmulti-hadron operators. The method is tested on the isoscalar mesons in the\nscalar, pseudoscalar, and vector channels, and on the two-pion system of total\nisospin I=0,1,2.",
        "positive": "Direct determination of the strange and light quark condensates from\n  full lattice QCD: We determine the strange quark condensate from lattice QCD for the first time\nand compare its value to that of the light quark and chiral condensates. The\nresults come from a direct calculation of the expectation value of the trace of\nthe quark propagator followed by subtraction of the appropriate perturbative\ncontribution, derived here, to convert the non-normal-ordered $m\\bar{\\psi}\\psi$\nto the $\\bar{MS}$ scheme at a fixed scale. This is then a well-defined physical\n`nonperturbative' condensate that can be used in the Operator Product Expansion\nof current-current correlators. The perturbative subtraction is calculated\nthrough $\\mathcal{O}(\\alpha_s)$ and estimates of higher order terms are\nincluded through fitting results at multiple lattice spacing values. The gluon\nfield configurations used are `second generation' ensembles from the MILC\ncollaboration that include 2+1+1 flavors of sea quarks implemented with the\nHighly Improved Staggered Quark action and including $u/d$ sea quarks down to\nphysical masses. Our results are : $<\\bar{s}{s}>^{\\bar{MS}}(2 \\mathrm{GeV})=\n-(290(15) \\mathrm{MeV})^3$, $<\\bar{l}{l}>^{\\bar{MS}}(2\\, \\mathrm{GeV})=\n-(283(2) \\mathrm{MeV})^3$, where $l$ is a light quark with mass equal to the\naverage of the $u$ and $d$ quarks. The strange to light quark condensate ratio\nis 1.08(16). The light quark condensate is significantly larger than the chiral\ncondensate in line with expectations from chiral analyses. We discuss the\nimplications of these results for other calculations."
    },
    {
        "anchor": "An Improved Upper Bound for the Ground State Energy of Fermion Lattice\n  Models: We present an improved upper bound for the ground state energy of lattice\nfermion models with sign problem. The bound can be computed by numerical\nsimulation of a recently proposed family of deformed Hamiltonians with no sign\nproblem. For one dimensional models, we expect the bound to be particularly\neffective and practical extrapolation procedures are discussed. In particular,\nin a model of spinless interacting fermions and in the Hubbard model at various\nfilling and Coulomb repulsion we show how such techniques can estimate ground\nstate energies and correlation function with great accuracy.",
        "positive": "Effects of Improvement: $f_\u03c0$ and $m_q$: We present a study of the effects of improvement on light-quark physics using\nthe Fermilab formalism. The calculations were performed at three different\nlattice spacings, with the SW action and traditional Wilson action (both\ntadpole improved). We find that $O(a)$ effects for the decay constant $f_\\pi$\nand quark mass $m_q$ can be successfully removed using the tadpole-improved SW\naction in the light-quark regime."
    },
    {
        "anchor": "Kaon physics: a lattice perspective: I critically review recent lattice QCD results relevant for kaon\nphenomenology, as well as the methods that are used to obtain them. The focus\nis on calculations with N_f=2 and N_f=2+1 flavors of sea quarks. Concerning\nmethodology, the subjects covered include a discussion of how best to\nextrapolate and/or interpolate results to the physical quark-mass point, a\nscheme for assessing the extent to which a lattice QCD calculation includes the\nvarious effects required to compute a given quantity reliably and a procedure\nfor averaging lattice results. The phenomenological topics that I review\ncomprise leptonic and semileptonic kaon decays, as well as neutral kaon mixing\nand CP violation in K->\\pi\\pi decays.",
        "positive": "Two-Color QCD with Chiral Chemical Potential: The phase diagram of two-color QCD with a chiral chemical potential is\nstudied on the lattice. The focus is on the confinement/deconfinement phase\ntransition and the breaking/restoration of chiral symmetry. The simulations are\ncarried out with dynamical staggered fermions without rooting. The dependence\nof the Polyakov loop, the chiral condensate and the corresponding\nsusceptibilities on the chiral chemical potential and the temperature are\npresented."
    },
    {
        "anchor": "Hadronic Spectral Functions above the QCD Phase Transition: We extract the spectral functions in the scalar, pseudo-scalar, vector, and\naxial vector channels above the deconfinement phase transition temperature (Tc)\nusing the maximum entropy method (MEM). We use anisotropic lattices, 32^3 * 32,\n40, 54, 72, 80, and 96 (corresponding to T = 2.3 Tc --> 0.8 Tc), with the\nrenormalized anisotropy xi = 4.0 to have enough temporal data points to carry\nout the MEM analysis. Our result suggests that the spectral functions continue\nto possess non-trivial structures even above Tc and in addition that there is a\nqualitative change in the state of the deconfined matter between 1.5 Tc and 2\nTc.",
        "positive": "Baryonic states in supersymmetric Yang-Mills theory: In $\\mathcal{N}$=1 supersymmetric Yang-Mills theory the superpartner of the\ngluon is the gluino, which is a spin 1/2 Majorana particle in the adjoint\nrepresentation of the gauge group. Combining three gluinos, it is possible to\nform colour neutral bound states, analogous to baryons in QCD. The correlation\nfunctions of the corresponding baryonic operators contain a contribution\nrepresented by a `sunset diagram', and in addition, unlike in QCD, another\ncontribution represented by a `spectacle diagram'. We present first results\nfrom an implementation and calculation of these objects, obtained from\nnumerical simulations of supersymmetric Yang-Mills theory."
    },
    {
        "anchor": "Quark Contraction Tool -- QCT: We present a Mathematica package for the calculation of Wick contractions in\nquantum field theories - QCT. Furthermore the package aims at automatically\ngenerating code for the calculation of physical matrix elements, suitable for\nnumerical evaluation in a C++ program. To that end commonly used algebraic\nmanipulations for the calculation of matrix elements in lattice QCD are\nimplemented.",
        "positive": "Complex-Temperature Singularities of the Susceptibility in the $d=2$\n  Ising Model. I. Square Lattice: We investigate the complex-temperature singularities of the susceptibility of\nthe 2D Ising model on a square lattice. From an analysis of low-temperature\nseries expansions, we find evidence that as one approaches the point $u=u_s=-1$\n(where $u=e^{-4K}$) from within the complex extensions of the FM or AFM phases,\nthe susceptibility has a divergent singularity of the form $\\chi \\sim\nA_s'(1+u)^{-\\gamma_s'}$ with exponent $\\gamma_s'=3/2$. The critical amplitude\n$A_s'$ is calculated. Other critical exponents are found to be\n$\\alpha_s'=\\alpha_s=0$ and $\\beta_s=1/4$, so that the scaling relation\n$\\alpha_s'+2\\beta_s+\\gamma_s'=2$ is satisfied. However, using exact results for\n$\\beta_s$ on the square, triangular, and honeycomb lattices, we show that\nuniversality is violated at this singularity: $\\beta_s$ is lattice-dependent.\nFinally, from an analysis of spin-spin correlation functions, we demonstrate\nthat the correlation length and hence susceptibility are finite as one\napproaches the point $u=-1$ from within the symmetric phase. This is confirmed\nby an explicit study of high-temperature series expansions."
    },
    {
        "anchor": "Automatic differentiation for error analysis of Monte Carlo data: Automatic Differentiation (AD) allows to determine exactly the Taylor series\nof any function truncated at any order. Here we propose to use AD techniques\nfor Monte Carlo data analysis. We discuss how to estimate errors of a general\nfunction of measured observables in different Monte Carlo simulations. Our\nproposal combines the $\\Gamma$-method with Automatic differentiation, allowing\nexact error propagation in arbitrary observables, even those defined via\niterative algorithms. The case of special interest where we estimate the error\nin fit parameters is discussed in detail. We also present a freely available\nfortran reference implementation of the ideas discussed in this work.",
        "positive": "'t Hooft surface in lattice gauge theory: We discuss the lattice formulation of the 't Hooft surface, that is, the\ntwo-dimensional surface operator of a dual variable. The 't Hooft surface\ndescribes the world sheets of topological vortices. We derive the formulas to\ncalculate the expectation value of the 't Hooft surface in the multiple-charge\nlattice Abelian Higgs model and in the lattice non-Abelian Higgs model. As the\nfirst demonstration of the formula, we compute the intervortex potential in the\ncharge-2 lattice Abelian Higgs model."
    },
    {
        "anchor": "The QCD Equation of State to $\\mathcal{O}(\u03bc_B^4)$ from Lattice QCD: We present first results from a first-principles calculation of the QCD\nequation of state to $\\mathcal{O}(\\mu_B^4)$, where $\\mu_B$ is the baryon\nchemical potential. We find that second-order corrections are sufficient for a\nlarge part of the freeze-out temperature and baryon chemical potential range\nachieved by the RHIC beam energy scan. Nevertheless, higher-order corrections\nare necessary to extend the validity of the equation of state down to beam\nenergies $s^{1/2}_{NN}\\sim 20$ GeV.",
        "positive": "Light Hadron Masses and Decay Constants: The extraction of the light hadron spectrum from a first-principle Quantum\nChromodynamics approach is a profound application for lattice simulations of\nQuantum Chromodynamics.\n  This review will cover recent lattice results for the masses and decay\nconstants of the light hadrons. In particular, the applicability of different\napproaches for the extrapolation towards the physical point will be discussed."
    },
    {
        "anchor": "Topological Susceptibility in Lattice QCD with Two Flavors of Dynamical\n  Quarks: We present a study of the topological susceptibility in lattice QCD with two\ndegenerate flavors of dynamical quarks. The topological charge is measured on\ngauge configurations generated with a renormalization group improved gauge\naction and a mean field improved clover quark action at three values of\n$\\beta=6/g^2$, corresponding to lattice spacings of $a \\approx 0.22$, 0.16 and\n0.11 fm, with four sea quark masses at each $\\beta$. The study is supplemented\nby simulations of pure SU(3) gauge theory with the same gauge action at 5\nvalues of $\\beta$ with lattice spacings 0.09 fm$\\simlt a \\simlt$0.27 fm. We\nemploy a field theoretic definition of the topological charge together with\ncooling. For the topological susceptibility in the continuum limit of pure\nSU(3) gauge theory we obtain $\\chi_t^{1/4} = 197^{+13}_{-16}$ MeV where the\nerror shows statistical and systematic ones added in quadrature. In full QCD\n$\\chi_t$ at heavy sea quark masses is consistent with that of pure SU(3) gauge\ntheory. A decrease of $\\chi_t$ toward light quark masses, as predicted by the\nanomalous Ward-Takahashi identity for U(1) chiral symmetry, becomes clearer for\nsmaller lattice spacings. The cross-over in the behavior of $\\chi_t$ from heavy\nto light sea quark masses is discussed.",
        "positive": "Lattice Regularized QCD at Finite Temperature: During the first part of this review we will focus on the thermodynamics of\n$SU(N)$ gauge theories at finite temperature. We will present results from a\ncalculation of electric and magnetic screening masses for the gluons, discuss\ncalculations of the critical temperature in units of the string tension and\nbulk thermodynamic quantities like the energy density and pressure. In\nparticular, the latter calculations have now reached a stage where $O(a^2)$\ncut-off effects can be controlled systematically and an extrapolation to the\ncontinuum limit can be performed. In the second part we discuss the critical\nbehaviour of QCD with light quarks. We analyze the chiral transition in\n2-flavour QCD and present results on the temperature dependence of hadron\nproperties."
    },
    {
        "anchor": "Thermal effects on quark-gluon mixed condensate g<\\bar{q} \u03c3G q>\n  from lattice QCD: We present the first study of the thermal effects on the quark-gluon mixed\ncondensate g<\\bar{q} \\sigma G q>, which is another chiral order parameter, in\nSU(3)c lattice QCD with the Kogut-Susskind fermion at the quenched level. Using\nthe lattices at \\beta=6.0, 6.1, 6.2 in high statistics, we calculate the mixed\ncondensate as well as the quark condensate in the chiral limit for the\ntemperature 0MeV <= T <= 500MeV. Except for the sharp decrease of both the\ncondensates around T_c \\simeq 280MeV, the thermal effects are found to be weak\nbelow T_c. We also find that the ratio m_0^2 = g<\\bar{q} \\sigma G q>/\n<\\bar{q}q> is almost independent of the temperature even in the very vicinity\nof T_c. This result indicates nontrivial similarity in the chiral behaviors of\nthe two different condensates.",
        "positive": "Fermionic observables in Numerical Stochastic Perturbation Theory: We present technical details of fermionic observables computations in NSPT.\nIn particular we discuss the construction of composite operators starting from\nthe inverse Dirac operator building block, the subtraction of UV divergences\nand the treatment of irrelevant contributions in extracting the continuum\nlimit."
    },
    {
        "anchor": "Monte Carlo Simulations with Indefinite and Complex-Valued Measures: A method is presented to tackle the sign problem in the simulations of\nsystems having indefinite or complex-valued measures. In general, this new\napproach is shown to yield statistical errors smaller than the crude Monte\nCarlo using absolute values of the original measures. Exactly solvable,\none-dimensional Ising models with complex temperature and complex activity\nillustrate the considerable improvements and the workability of the new method\neven when the crude one fails.",
        "positive": "Light Meson Form Factors at near Physical Masses: The ability for most hadrons to decay via strong interactions prevents the\ndirect measurement of their electromagnetic properties. However, a detailed\nunderstanding of how these resonant states feature in scattering processes can\nallow one to disentangle such information from photo production processes. In\nparticular, there has been increasing interest in the determination of magnetic\ndipole moments using such methods. In a recent study, Gudino et al. provide the\nfirst experimental determination of the magnetic dipole moment of the rho\nmeson. To facilitate a comparison with this experimental determination, we\npresent a calculation of the rho meson and pion electromagnetic form factors\ncalculated in the framework of Lattice QCD. Using the PACS-CS 2+1 flavour full\nQCD gauge field configurations, we are able to access low $Q^2$ values at\nnear-physical quark masses. Through the use of variational techniques, we\ncontrol excited state systematics in the matrix elements of the lowest-lying\nstates and gain access to the matrix elements of the first excited state. Our\ndetermination of the rho meson $g$-factor $g_{\\rho} = 2.21(8)$ is in excellent\nagreement with this experimental determination, but with a significantly\nsmaller uncertainty."
    },
    {
        "anchor": "The magnetic susceptibility in QCD: Recently much work has been devoted to the study of QCD coupled to a\nbackground magnetic field. Strongly interacting matter acts as a magnetic\nmedium and it is natural to study the properties of this medium, in particular\nto understand if it behaves like a diamagnetic or a paramagnetic material. A\nserious difficulty in studying these properties by means of LQCD simulations is\nthe quantization of the magnetic field in a toroidal geometry. We will expose a\nmethod to overcome this difficulty and we will present data obtained for the\n$N_f=2$ theory that show that the QCD medium is paramagnetic.",
        "positive": "Large $N_c$ Thermodynamics with Dynamical Fermions: We present a progress report on our investigation of the thermodynamics of\nQCD with $N_f=2$ flavors of dynamical Wilson fermions in the limit of a large\nnumber of colors $N_c$. To date, studies of the thermodynamics of QCD at large\n$N_c$ have been limited to the quenched approximation, i.e., to the behavior of\npure $\\mathrm{SU}(N_c)$ gauge theory at large $N_c$. This is the first study of\nthermodynamics at large $N_c$ using dynamical fermions, and thus the first\nstudy able to test whether the quenched approximation is a valid way to\ninvestigate large $N_c$ thermodynamics. After reviewing 't Hooft's large $N_c$\nlimit, we discuss the automation we use to make this study feasible, and\nfinally compare our preliminary physics results for $\\mathrm{SU}(3-5)$ with\nlarge $N_c$ expectations."
    },
    {
        "anchor": "Electromagnetic form factors at large momenta from lattice QCD: Accessing hadronic form factors at large momentum transfers has traditionally\npresented a challenge for lattice QCD simulations. Here we demonstrate how a\nnovel implementation of the Feynman-Hellmann method can be employed to\ncalculate hadronic form factors in lattice QCD at momenta much higher than\npreviously accessible. Our simulations are performed on a single set of gauge\nconfigurations with three flavours of degenerate mass quarks corresponding to\n$m_\\pi \\approx 470 \\text{ MeV}$. We are able to determine the electromagnetic\nform factors of the pion and nucleon up to approximately $6 \\text{ GeV}^2$,\nwith results for $G_E/G_M$ in the proton agreeing well with experimental\nresults.",
        "positive": "Parallel Programming with Matrix Distributed Processing: Matrix Distributed Processing (MDP) is a C++ library for fast development of\nefficient parallel algorithms. It constitues the core of FermiQCD. MDP enables\nprogrammers to focus on algorithms, while parallelization is dealt with\nautomatically and transparently. Here we present a brief overview of MDP and\nexamples of applications in Computer Science (Cellular Automata), Engineering\n(PDE Solver) and Physics (Ising Model)."
    },
    {
        "anchor": "Lemon: an MPI parallel I/O library for data encapsulation using LIME: We introduce Lemon, an MPI parallel I/O library that is intended to allow for\nefficient parallel I/O of both binary and metadata on massively parallel\narchitectures. Motivated by the demands of the Lattice Quantum Chromodynamics\ncommunity, the data is stored in the SciDAC Lattice QCD Interchange Message\nEncapsulation format. This format allows for storing large blocks of binary\ndata and corresponding metadata in the same file. Even if designed for LQCD\nneeds, this format might be useful for any application with this type of data\nprofile. The design, implementation and application of Lemon are described. We\nconclude with presenting the excellent scaling properties of Lemon on state of\nthe art high performance computers.",
        "positive": "The Overlap-Dirac Operator: Topology and Chiral Symmetry Breaking: We review the spectral flow techniques for computing the index of the overlap\nDirac operator including results relevant for SUSY Yang-Mills theories. We\ndescribe properties of the overlap Dirac operator, and methods to implement it\nnumerically. We use the results from the spectral flow to illuminate the\ndifficulties in numerical calculations involving domain wall and overlap\nfermions."
    },
    {
        "anchor": "Exploring the phase diagram of QCD with complex Langevin simulations: Simulations of QCD with a finite chemical potential typically lead to a\nsevere sign problem, prohibiting any standard Monte Carlo approach. Complex\nLangevin simulations provide an alternative to sample path integrals with\noscillating weight factors and therefore potentially enable the determination\nof the phase diagram of QCD. Here we present results for QCD in the limit of\nheavy quarks and show evidence that the phase diagram can be mapped out by\ndirect simulation. We apply adaptive step-size scaling and adaptive gauge\ncooling to ensure the convergence of these simulations.",
        "positive": "An Effective Action for Finite Temperature QCD with Fermions: Using lattice perturbation theory at finite temperature, we compute for\nstaggered fermions the one-loop fermionic corrections to the spatial and\ntemporal plaquette couplings as well as the leading $Z_N$ symmetry breaking\ncoupling. Numerical and analytical considerations indicate that the finite\ntemperature corrections to the zero-temperature calculation of A. Hasenfratz\nand T. DeGrand are small for small values of $\\kappa = {1\\over 2m_F}$, but\nbecome significant for intermediate values of $\\kappa$. The effect of these\nfinite temperature corrections is to ruin the agreement of the\nHasenfratz-DeGrand calculation with Monte Carlo data. We conjecture that the\nfinite temperature corrections are suppressed nonperturbatively at low\ntemperatures, resolving this apparent disagreement. The $Z_N$ symmetry breaking\ncoupling is small; we argue that it may change the order of the transition\nwhile having little effect on the critical value of $\\beta$."
    },
    {
        "anchor": "Density of states techniques for lattice field theories using the\n  functional fit approach (FFA): We discuss a variant of density of states (DoS) techniques for lattice field\ntheories, the so-called \"functional fit approach\" (FFA). The DoS FFA is based\non a density of states rho(x) which is parameterized on small intervals of the\nargument x of rho(x). On these intervals restricted Monte Carlo simulations\nwith an additional Boltzmann factor exp(lambda x) allow to determine rho(x)\nvery precisely by obtaining its parameters from fitting the Monte Carlo data to\na known function of lambda. We describe the method in detail and show its\napplicability in four different systems, three of which have a complex action\nproblem: The SU(3) spin model with a chemical potential, U(1) lattice gauge\ntheory, the Z(3) spin model with chemical potential, and 2-dimensional U(1)\nlattice gauge theory with a topological term. In all cases we compare to\nreference calculations, which partly were done in a dual formulation where the\ncomplex action problem is absent. In all four cases we find a very encouraging\nperformance of the DoS FFA.",
        "positive": "Complex Heavy-Quark Potential at Finite Temperature from Lattice QCD: We calculate for the first time the complex potential between a heavy quark\nand antiquark at finite temperature across the deconfinement transition in\nlattice QCD. The real and imaginary part of the potential at each separation\ndistance $r$ is obtained from the spectral function of the thermal Wilson loop.\nWe confirm the existence of an imaginary part above the critical temperature\n$T_C$, which grows as a function of $r$ and underscores the importance of\ncollisions with the gluonic environment for the melting of heavy quarkonia in\nthe quark-gluon-plasma."
    },
    {
        "anchor": "Properties of canonical determinants and a test of fugacity expansion\n  for finite density lattice QCD with Wilson fermions: We analyze canonical determinants, i.e., grand canonical determinants\nprojected to a fixed net quark number. The canonical determinants are the\ncoefficients in a fugacity expansion of the grand canonical determinant and we\nevaluate them as the Fourier moments of the grand canonical determinant with\nrespect to imaginary chemical potential, using a dimensional reduction\ntechnique. The analysis is done for two mass-degenerate flavors of Wilson\nfermions at several temperatures below and above the confinement/deconfinement\ncrossover. We discuss various properties of the canonical determinants and\nanalyse the convergence of the fugacity series for different temperatures.",
        "positive": "$N_f = 1+2+1$ QCD+QED simulations with C$^\\star$ boundary conditions: We give an update on the ongoing effort of the RC$^\\star$ collaboration to\ngenerate fully dynamical QCD+QED configurations with C$^\\star$ boundary\nconditions using the openQ$^\\star$D code. The simulations are tuned to the\nU-symmetric point ($m_d=m_s$) with pions at $m_{\\pi^\\pm}\\approx 400$ MeV. The\nsplitting of the light mesons is used as one of three tuning observables and\nfixed to $m_{K^0} - m_{K^\\pm} \\approx 5$ MeV and $m_{K^0} - m_{K^\\pm} \\approx\n25$ MeV on ensembles with renormalized electromagnetic coupling\n$\\alpha_\\mathrm{R} \\approx \\alpha_\\mathrm{phys.}$ and $\\alpha_\\mathrm{R}\\approx\n5.5 \\alpha_\\mathrm{phys.}$ respectively. We will discuss some details\nconcerning our tuning strategy and present the calculation of the meson and\nbaryon masses. Finally, we will also present a cost analysis for our\nsimulations. More technical details on finite-volume effects and the tuning can\nbe found in A. Cotellucci's proceedings."
    },
    {
        "anchor": "The three-loop beta-fuction of QCD with the clover action: We calculate, to 3 loops in perturbation theory, the bare $\\beta$-function of\nQCD, formulated on the lattice with the clover fermionic action. The dependence\nof our result on the number of colors $N$, the number of fermionic flavors\n$N_f$, as well as the clover parameter $c_{SW}$, is shown explicitly.\n  A direct outcome of our calculation is the two-loop relation between the bare\ncoupling constant $g_0$ and the one renormalized in the MS-bar scheme.\n  Further, we can immediately derive the three-loop correction to the relation\nbetween the lattice $\\Lambda$-parameter and $g_0$, which is important in checks\nof asymptotic scaling. For typical values of $c_{SW}$, this correction is found\nto be very pronounced.",
        "positive": "Finite-Temperature Spectral Functions from the Functional\n  Renormalization Group: We present a method to obtain spectral functions at finite temperature from\nthe Functional Renormalization Group. Our method is based on a\nthermodynamically consistent truncation of the flow equations for 2-point\nfunctions with analytically continued frequency components in the originally\nEuclidean external momenta. For the uniqueness of this continuation at finite\ntemperature we furthermore implement the physical Baym-Mermin boundary\nconditions. Results are presented for mesonic spectral functions obtained from\na two-flavor quark-meson model."
    },
    {
        "anchor": "Proton decay matrix elements on the lattice: Hadronic matrix elements of proton decay are essential ingredients to bridge\nthe grand unification theory to low energy observables like proton lifetime. In\nthis paper we non-perturbatively calculate the matrix elements, relevant for\nthe process of a nucleon decaying into a pseudoscalar meson and an anti-lepton\nthrough generic baryon number violating four-fermi operators. Lattice QCD with\n2+1 flavor dynamical domain-wall fermions with the {\\it direct} method, which\nis direct measurement of matrix element from three-point function without\nchiral perturbation theory, are used for this study to have good control over\nthe lattice discretization error, operator renormalization, and chiral\nextrapolation. The relevant form factors for possible transition process from\nan initial proton or neutron to a final pion or kaon induced by all types of\nthree quark operators are obtained through three-point functions of\n(nucleon)-(three-quark operator)-(meson) with physical kinematics. In this\nstudy all the relevant systematic uncertainties of the form factors are taken\ninto account for the first time, and the total error is found to be the range\n30%-40% for $\\pi$ and 20%-40% for $K$ final states.",
        "positive": "Comparing topological charge definitions using topology fixing actions: We investigate both the hyperbolic action and the determinant ratio action\ndesigned to fix the topological charge on the lattice. We show to what extent\ntopology is fixed depending on the parameters of these actions, keeping the\nphysical situation fixed. At the same time the agreement between different\ndefinitions of topological charge - the field theoretic and the index\ndefinition - is directly correlated to the degree topology is fixed. Moreover,\nit turns out that the two definitions agree very well. We also study finite\nvolume effects arising in the static potential and related quantities due to\ntopology fixing."
    },
    {
        "anchor": "QCD with overlap fermions: Running coupling and the 3-loop beta-function: We calculate the relation between the bare coupling constant g_0 and the\nMSbar-renormalized coupling g_MS: g_0 = Z_g(g_0,a \\mu) g_MS, to 2 loops in\nperturbation theory. We employ the standard Wilson action for gluons and the\noverlap action for fermions. For convenience, we have worked with the\nbackground field technique, which only requires evaluation of 2-point Green's\nfunction for the problem at hand. Our results depend explicitly on the number\nof fermion flavors (N_f) and colors (N). Since the dependence of Z_g on the\noverlap parameter rho cannot be extracted analytically, we tabulate our results\nfor different values in the allowed range of rho (0 < rho < 2), focusing on\nvalues which are being used most frequently in simulations. Knowledge of Z_g\nallows us to derive the 3-loop coefficient of the bare beta-function\n(beta_L(g_0)) which, unlike the 1- and 2-loop coefficients, is\nregularization-dependent. The nontrivial dependence of Z_g and of beta_L(g_0)\non rho is plotted for various choices of N, N_f.",
        "positive": "Neutral B Meson Mixing and Heavy-light Decay Constants from Quenched\n  Lattice QCD: We present high-statistics results for neutral $B$-meson mixing and\nheavy-light-meson leptonic decays in the quenched approximation from\ntadpole-improved clover actions at $\\beta = 6.0$ and $\\beta = 6.2$. We consider\nquantities such as $B_{B_{d(s)}}$, $f_{D_{d(s)}}$, $f_{B_{d(s)}}$ and the full\n$\\Delta B=2$ matrix elements as well as the corresponding SU(3)-breaking\nratios. These quantities are important for determining the CKM matrix element\n$|V_{td}|$."
    },
    {
        "anchor": "Multiscale Monte Carlo equilibration: Two-color QCD with two fermion\n  flavors: We demonstrate the applicability of a recently proposed multiscale\nthermalization algorithm to two-color quantum chromodynamics (QCD) with two\nmass-degenerate fermion flavors. The algorithm involves refining an ensemble of\ngauge configurations that had been generated using a renormalization group (RG)\nmatched coarse action, thereby producing a fine ensemble that is close to the\nthermalized distribution of a target fine action; the refined ensemble is\nsubsequently rethermalized using conventional algorithms. Although the\ngeneralization of this algorithm from pure Yang-Mills theory to QCD with\ndynamical fermions is straightforward, we find that in the latter case, the\nmethod is susceptible to numerical instabilities during the initial stages of\nrethermalization when using the hybrid Monte Carlo algorithm. We find that\nthese instabilities arise from large fermion forces in the evolution, which are\nattributed to an accumulation of spurious near-zero modes of the Dirac\noperator. We propose a simple strategy for curing this problem, and demonstrate\nthat rapid thermalization--as probed by a variety of gluonic and fermionic\noperators--is possible with the use of this solution. In addition, we study the\nsensitivity of rethermalization rates to the RG matching of the coarse and fine\nactions, and identify effective matching conditions based on a variety of\nmeasured scales.",
        "positive": "Isospin splittings in the decuplet baryon spectrum from dynamical\n  QCD+QED: We report a new analysis of the isospin splittings within the decuplet baryon\nspectrum. Our numerical results are based upon five ensembles of dynamical\nQCD+QED lattices. The analysis is carried out within a flavour-breaking\nexpansion which encodes the effects of breaking the quark masses and\nelectromagnetic charges away from an approximate SU(3) symmetric point. The\nresults display total isospin splittings within the approximate SU(2)\nmultiplets that are compatible with phenomenological estimates. Further, new\ninsight is gained into these splittings by separating the contributions arising\nfrom strong and electromagnetic effects. We also present an update of earlier\nresults on the octet baryon spectrum."
    },
    {
        "anchor": "Recent results on B mixing and decay constants from HPQCD: We review recent results for B_d and B_s mixing parameters using MILC N_f=2+1\nlattices, NRQCD b-quarks and AsqTad light quarks. Latest numbers for decay\nconstants f_B and f_{B_s} are also presented. Combining our lattice results\nwith experimental determinations of the mass differences \\Delta M_d and \\Delta\nM_s leads to an important ratio of elements of the CKM matrix,\n|V_{td}|/|V_{ts}| = 0.214(1)(5) and an updated Standard Model number for the\nbranching fraction Br(B_s -> mu^+ mu^-) = 3.19(19) x 10^{-9}. Preliminary new\nresults for f_{B_s} based on other actions are also described.",
        "positive": "The Density of States Method at Finite Chemical Potential: We study the density of states method to explore the phase diagram of the\nchiral transition on the temperature and quark chemical potential plane. Four\nquark flavors are used in the analysis. Though the method is quite expensive\nsmall lattices show an indication for a triple-point connecting three different\nphases on the phase diagram."
    },
    {
        "anchor": "Heavy Dynamical Fermions in Lattice QCD: It is expected that the only effect of heavy dynamical fermions in QCD is to\nrenormalize the gauge coupling. We derive a simple expression for the shift in\nthe gauge coupling induced by $N_f$ flavors of heavy fermions. We compare this\nformula to the shift in the gauge coupling at which the\nconfinement-deconfinement phase transition occurs (at fixed lattice size) from\nnumerical simulations as a function of quark mass and $N_f$. We find remarkable\nagreement with our expression down to a fairly light quark mass. However,\nsimulations with eight heavy flavors and two light flavors show that the eight\nflavors do more than just shift the gauge coupling. We observe\nconfinement-deconfinement transitions at $\\beta=0$ induced by a large number of\nheavy quarks. We comment on the relevance of our results to contemporary\nsimulations of QCD which include dynamical fermions.",
        "positive": "Schroedinger functional formalism with domain-wall fermion: Finite volume renormalization scheme is one of the most fascinating scheme\nfor non-perturbative renormalization on lattice.\n  By using the step scaling function one can follow running of renormalized\nquantities with reasonable cost.\n  It has been established the Schroedinger functional is very convenient to\ndefine a field theory in a finite volume for the renormalization scheme.\n  The Schroedinger functional, which is characterized by a\n  Dirichlet boundary condition in temporal direction, is well defined and works\nwell for the Yang-Mills theory and QCD with the Wilson fermion.\n  However one easily runs into difficulties if one sets the same sort of the\nDirichlet boundary condition for the overlap Dirac operator or the domain-wall\nfermion.\n  In this paper we propose an orbifolding projection procedure to impose the\nSchroedinger functional Dirichlet boundary condition on the domain-wall\nfermion."
    },
    {
        "anchor": "Charmonium spectrum including higher spin and exotic states: We study the charmonium spectrum including higher spin and exotic states. We\nuse the Sheikholeslami-Wilson (clover) action for $N_f=2$ sea quarks as well as\nfor the charm valence quark. In order to access excited states we apply a\nvariational method with a basis of highly optimized operators.",
        "positive": "Lattice QCD with a chiral twist: In these lectures I explain how chiral symmetry of continuum QCD naturally\nleads to a class of lattice regularisations known as twisted mass QCD (tmQCD).\nAs compared to standard Wilson quarks, its advantages are the absence of\nunphysical zero modes, the possibility to circumvent lattice renormalisation\nproblems and automatic O(a) improvement. On the other hand, the physical parity\nand flavour symmetries are explicitly broken. I discuss these aspects and then\nturn to the theory in a finite space-time volume with Schroedinger functional\nboundary conditions. Again, chiral transformations of the continuum theory may\nbe used as a guide to formulate an alternative lattice regularisation of the\nSchr\\\"odinger functional, with interesting applications to renormalization\nproblems in QCD."
    },
    {
        "anchor": "Search for Chiral Fermion Actions on Non-Orthogonal Lattices: The graphene-inspired fermion actions recently proposed by Creutz and Borici\nhave sparked interest in the use of non-orthogonal lattices in lattice QCD.\nThese fermion actions have the desired chiral symmetry and have the minimal\ndoubling required by the Nielsen-Ninomiya no-go theorem. However, due to the\nlack of discrete symmetries, radiative corrections in the gauged lattice theory\nwill lead to the generation of unwanted relevant and marginal operators. Other\nsimilarly motivated non-orthogonal fermion actions avoid these unwanted\noperators, but introduce incorrect continuum behavior or excessive fermion\ndoubling. A delicate balance of symmetry is required for chiral symmetry,\nminimal doubling, and no relevant operators, and to date, no non-orthogonal\nlattice action has accomplished this balance.",
        "positive": "Speeding up finite step-size updating of full QCD on the lattice: We propose various improvements of finite step-size updating for full QCD on\nthe lattice that might turn finite step-size updating into a viable alternative\nto the hybrid Monte Carlo algorithm. These improvements are noise reduction of\nthe noisy estimator of the fermion determinant, unbiased inclusion of the\nhopping parameter expansion and a multi-level Metropolis scheme. First\nnumerical tests are performed for the 2 dimensional Schwinger model with two\nflavours of Wilson fermions and for QCD two flavours of Wilson fermions and\nSchr\"odinger functional boundary conditions."
    },
    {
        "anchor": "Calculation of $\u0394I = 3/2$ kaon weak matrix elements including\n  two-pion interaction effects in finite volume: We calculate $\\Delta I = 3/2$ kaon decay matrix elements using domain wall\nfermions and the DBW2 gauge action at one coarse lattice spacing corresponding\nto $a^{-1} = 1.3$ GeV. We employ the Lellouch and L\\\"uscher formula and its\nextention for non-zero total momentum to extract the infinite volume,\ncenter-of-mass frame decay amplitudes. The decay amplitudes obtained from the\nmethods correspond to those from the indirect method with full order chiral\nperturbation theory. We confirm that the result is consistent with the previous\nresult calculated with H-parity (anti-periodic) boundary condition by\ninvestigating the relative momentum dependence. We evaluate the decay amplitude\nRe$A_2$ at the physical point by a chiral extrapolation with a polynomial\nfunction of $m_\\pi^2$ and the relative momentum as well as the Delta I = 3/2\nelectroweak penguin contributions to $\\epsilon^\\prime / \\epsilon$. We found\nthat the result of Re$A_2$ reasonably agrees with the experiment.",
        "positive": "Neutral B-meson mixing from three-flavor lattice QCD: Determination of\n  the SU(3)-breaking ratio \u03be: We study SU(3)-breaking effects in the neutral B_d-\\bar B_d and B_s-\\bar B_s\nsystems with unquenched N_f=2+1 lattice QCD. We calculate the relevant matrix\nelements on the MILC collaboration's gauge configurations with asqtad-improved\nstaggered sea quarks. For the valence light-quarks (u, d, and s) we use the\nasqtad action, while for b quarks we use the Fermilab action. We obtain\n\\xi=f_{B_s}\\sqrt{B_{B_s}}/f_{B_d}\\sqrt{B_{B_d}}=1.268+-0.063. We also present\nresults for the ratio of bag parameters B_{B_s}/B_{B_d} and the ratio of CKM\nmatrix elements |V_{td}|/|V_{ts}|. Although we focus on the calculation of \\xi,\nthe strategy and techniques described here will be employed in future extended\nstudies of the B mixing parameters \\Delta M_{d,s} and \\Delta\\Gamma_{d,s} in the\nStandard Model and beyond."
    },
    {
        "anchor": "Scaling tests in $\\Or(a)$--improved quenched lattice QCD: We present a scaling investigation of renormalized correlation functions in\n$\\Or(a)$--improved quenched lattice QCD. As one observable the renormalized\nPCAC quark mass is considered, others are constructed such that they become the\nvector meson mass, and the pseudoscalar and vector meson decay constants in\nlarge volume. Presently, we remain in intermediate volume, $(0.75^3\\times1.5)\n{fm}^4$, and study the approach to the continuum limit.",
        "positive": "Pion valence quark distribution from current-current correlation in\n  lattice QCD: We extract the pion valence quark distribution $q^\\pi_{\\rm v}(x)$ from\nlattice QCD (LQCD) calculated matrix elements of spacelike correlations of one\nvector and one axial vector current analyzed in terms of QCD collinear\nfactorization, using a new short-distance matching coefficient calculated to\none-loop accuracy. We derive the Ioffe time distribution of the two-current\ncorrelations in the physical limit by investigating the finite lattice spacing,\nvolume, quark mass, and higher-twist dependencies in a simultaneous fit of\nmatrix elements computed on four gauge ensembles. We find remarkable\nconsistency between our extracted $q^\\pi_{\\rm v}(x)$ and that obtained from\nexperimental data across the entire $x$-range. Further, we demonstrate that the\none-loop matching coefficient relating the LQCD matrix computed in position\nspace to the $q_{\\rm v}^{\\pi}(x)$ in momentum space has well-controlled\nbehavior with Ioffe time. This justifies that LQCD calculated current-current\ncorrelations are good observables for extracting partonic structures by using\nQCD factorization, which complements to the global effort to extract partonic\nstructure from experimental data."
    },
    {
        "anchor": "Lattice Lindblad simulation: We perform the real-time lattice simulation of an open quantum system, which\nis based on the Schwinger-Keldysh path integral representation of the Lindblad\nformalism. Although the real-time simulation generally suffers from the sign\nproblem, there exist a few exceptional cases. We focus on a sign-problem-free\nsystem of a non-relativistic spinless fermion and analyze time evolution under\ndriving and dissipation.",
        "positive": "Topology, fermionic zero modes and flavor singlet correlators in finite\n  temperature QCD: We compute the screening correlators in the sigma and eta' flavor singlet\nchannels in finite temperature QCD with 2 light quark flavors. Together with\nthe correlators in the pi and delta channels, these are used to discuss several\nissues related to symmetry restoration and the nature of the QCD phase\ntransition. Our calculations span a range of temperature extending from\napproximately 125 MeV to 170 MeV and are carried out in the context of a\nstaggered fermion formulation on a 16^3x8 lattice. In addition to the\ncomputation at a fixed quark mass (am_q=0.00625), we discuss the issue of the\nchiral limit. After careful consideration of the zero-mode shift lattice\nartefact, we present rather strong (topological) arguments in favor of the\nnon-restoration of U_A(1) at T_c."
    },
    {
        "anchor": "A cluster algorithm for Lattice Gauge Theories: A new algorithm for simulating compact U(1) lattice gauge theory in three\ndimensions is presented which is based on global changes in the configuration\nspace. We show that this algorithm provides an effective way to extract\npartition functions at given external flux. As an application, we study\nnumerically the finite temperature deconfinement phase transition.",
        "positive": "Running quark mass in two flavor QCD: We present first results for the step scaling function sigma_P of the\nrenormalization factor Z_P of the pseudoscalar density. The simulations are\nperformed within the framework of the Schroedinger functional with two flavors\nof O(a) improved Wilson fermions. The knowledge of sigma_P is required to\ncompute the renormalization group invariant quark masses. We also study the\nperformance of a variant of the HMC algorithm using two pseudofermion fields."
    },
    {
        "anchor": "Nucleon form factors on a large volume lattice near the physical point\n  in 2+1 flavor QCD: We present results for the isovector nucleon form factors measured on a\n$96^4$ lattice at almost the physical pion mass with a lattice spacing of 0.085\nfm in 2+1 flavor QCD. The configurations are generated with the stout-smeared\n$O(a)$-improved Wilson quark action and the Iwasaki gauge action at\n$\\beta$=1.82. The pion mass at the simulation point is about 146 MeV. A large\nspatial volume of $(8.1~{\\rm fm})^3$ allows us to investigate the form factors\nin the small momentum transfer region. We determine the isovector electric\nradius and magnetic moment from nucleon electric ($G_E$) and magnetic ($G_M$)\nform factors as well as the axial-vector coupling $g_A$. We also report on the\nresults of the axial-vector ($F_A$), induced pseudoscalar ($F_P$) and\npseudoscalar ($G_P$) form factors in order to verify the axial Ward-Takahashi\nidentity in terms of the nucleon matrix elements, which may be called the\ngeneralized Goldberger-Treiman relation.",
        "positive": "Interactions of $\u03c0K$, $\u03c0\u03c0K$ and $KK\u03c0$ systems at maximal\n  isospin from lattice QCD: We study the interactions of systems of two and three nondegenerate mesons\ncomposed of pions and kaons at maximal isospin using lattice QCD, specifically\n$\\pi^+K^+$, $\\pi^+\\pi^+K^+$ and $K^+K^+\\pi^+$. Utilizing the stochastic LapH\nmethod, we determine the spectrum of these systems on two CLS $N_f=2+1$\nensembles with pion masses of $200$ MeV and $340$ MeV, and include many levels\nin different momentum frames. We constrain the K matrices describing two- and\nthree-particle interactions by fitting the spectrum to the results predicted by\nthe finite-volume formalism, including up to $p$ waves. This requires also\nresults for the $\\pi^+\\pi^+$ and $K^+ K^+$ spectrum, which have been obtained\npreviously on the same configurations. We explore different fitting strategies,\ncomparing fits to energy shifts with fits to energies boosted to the rest\nframe, and also comparing simultaneous global fits to all relevant two- and\nthree-particle channels to those where we first fit two-particle channels and\nthen add in the three-particle information. We provide the first determination\nof the three-particle K matrix in $\\pi^+\\pi^+K^+$ and $K^+ K^+ \\pi^+$ systems,\nfinding statistically significant nonzero results in most cases. We include $s$\nand $p$ waves in the K matrix for $\\pi^+ K^+$ scattering, finding evidence for\nan attractive $p$-wave scattering length. We compare our results to Chiral\nPerturbation Theory, including an investigation of the impact of discretization\nerrors, for which we provide the leading order predictions obtained using\nWilson Chiral Perturbation Theory."
    },
    {
        "anchor": "Chiral magnetic effect in lattice QCD with a chiral chemical potential: We perform a first lattice QCD simulation including two-flavor dynamical\nfermion with a chiral chemical potential. Because the chiral chemical potential\ngives rise to no sign problem, we can exactly analyze a chirally imbalanced QCD\nmatter by the Monte Carlo simulation. By applying an external magnetic field to\nthis system, we obtain a finite induced current along the magnetic field, which\ncorresponds to the chiral magnetic effect. The obtained induced current is\nproportional to the magnetic field and to the chiral chemical potential, which\nis consistent with an analytical prediction.",
        "positive": "Double-pass variants for multi-shift BiCGstab(ell): In analogy to Neuberger's double-pass algorithm for the Conjugate Gradient\ninversion with multi-shifts we introduce a double-pass variant for\nBiCGstab(ell). One possible application is the overlap operator of QCD at\nnon-zero chemical potential, where the kernel of the sign function is\nnon-Hermitian. The sign function can be replaced by a partial fraction\nexpansion, requiring multi-shift inversions. We compare the performance of the\nnew method with other available algorithms, namely partial fraction expansions\nwith restarted FOM inversions and the Krylov-Ritz method using nested Krylov\nsubspaces."
    },
    {
        "anchor": "Large N lattice QCD and its extended strong-weak connection to the\n  hypersphere: We calculate an effective Polyakov line action of QCD at large Nc and large\nNf from a combined lattice strong coupling and hopping expansion working to\nsecond order in both, where the order is defined by the number of windings in\nthe Polyakov line. We compare with the action, truncated at the same order, of\ncontinuum QCD on S^1 x S^d at weak coupling from one loop perturbation theory,\nand find that a large Nc correspondence of equations of motion found in\n\\cite{Hollowood:2012nr} at leading order, can be extended to the next order.\nThroughout the paper, we review the background necessary for computing higher\norder corrections to the lattice effective action, in order to make higher\norder comparisons more straightforward.",
        "positive": "Coupling Yang-Mills with Causal Dynamical Triangulations: We discuss the algorithmic problem of minimal coupling gauge fields of the\nYang-Mills type to Quantum Gravity in the approach known as Causal Dynamical\nTriangulations (CDT) as a step towards studying, ultimately, systems of gravity\ncoupled with bosonic and fermionic matter. We first describe the algorithm for\ngeneral dimensions and gauge groups and then focus on the results obtained from\nsimulations of 2d CDT coupled to gauge fields with U{(1)} and SU{(2)} gauge\ngroups, where we studied both observables related to gravity and gauge fields,\nand compared them with analogous simulations in the static flat case."
    },
    {
        "anchor": "Spurious poles in a finite volume: Using effective-range expansion for the two-body amplitudes may generate\nspurious sub-threshold poles outside of the convergence range of the expansion.\nIn the infinite volume, the emergence of such poles leads to the\ninconsistencies in the three-body equations, e.g., to the breakdown of\nunitarity. We investigate the effect of the spurious poles on the three-body\nquantization condition in a finite volume and show that it leads to a peculiar\ndependence of the energy levels on the box size $L$. Furthermore, within a\nsimple model, it is demonstrated that the procedure for the removal of these\npoles, which was recently proposed in Ref.[1] in the infinite volume, can be\nadapted to the finite-volume calculations. The structure of the exact energy\nlevels is reproduced with an accuracy that systematically improves order by\norder in the EFT expansion.",
        "positive": "The unitary Fermi gas at finite temperature: momentum distribution and\n  contact: The Unitary Fermi Gas (UFG) is one of the most strongly interacting systems\nknown to date, as it saturates the unitarity bound on the quantum mechanical\nscattering cross section. The UFG corresponds to a two-component Fermi gas in\nthe limit of short interaction range and large scattering length, and is\ncurrently realized in ultracold-atom experiments via Feshbach resonances. While\neasy to define, the UFG poses a challenging quantum many-body problem, as it\nlacks any characteristic scale other than the density. As a consequence,\naccurate quantitative predictions of the thermodynamic properties of the UFG\nrequire Monte Carlo calculations. However, significant progress has also been\nmade with purely analytical methods. Notably, in 2005 Tan derived a set of\nexact thermodynamic relations in which a universal quantity known as the\n\"contact\" C plays a crucial role. Recently, C has also been found to determine\nthe prefactor of the high- frequency power-law decay of correlators as well as\nthe right-hand-sides of shear- and bulk viscosity sum rules. The contact is\ntherefore a central piece of information on the UFG in equilibrium as well as\naway from equilibrium. In this talk we describe some of the known aspects of\nFermi gases at and around unitarity, show our latest Monte Carlo results for\nthe contact at finite temperature, and summarize the open questions in the\nfield, some of which we are starting to answer using large-scale Monte Carlo\ncalculations by adapting methods from Lattice QCD."
    },
    {
        "anchor": "Alternatives to the stochastic \"noise vector\" approach: Several important observables, like the quark condensate and the Taylor\ncoefficients of the expansion of the QCD pressure with respect to the chemical\npotential, are based on the trace of the inverse Dirac operator and of its\npowers. Such traces are traditionally estimated with \"noise vectors\"\nsandwiching the operator. We explore alternative approaches based on polynomial\napproximations of the inverse Dirac operator.",
        "positive": "Towards the continuum limit of a $(1+1)$d quantum link Schwinger model: The solution of gauge theories is one of the most promising applications of\nquantum technologies. Here, we discuss the approach to the continuum limit for\n$U(1)$ gauge theories regularized via finite-dimensional Hilbert spaces of\nquantum spin-$S$ operators, known as quantum link models. For quantum\nelectrodynamics (QED) in one spatial dimension, we numerically demonstrate the\ncontinuum limit by extrapolating the ground state energy, the scalar, and the\nvector meson masses to large spin lengths $S$, large volume $N$, and vanishing\nlattice spacing $a$. By exactly solving Gauss' law for arbitrary $S$, we obtain\na generalized PXP spin model and count the physical Hilbert space dimension\nanalytically. This allows us to quantify the required resources for reliable\nextrapolations to the continuum limit on quantum devices. We use a functional\nintegral approach to relate the model with large values of half-integer spins\nto the physics at topological angle $\\Theta=\\pi$. Our findings indicate that\nquantum devices will in the foreseeable future be able to quantitatively probe\nthe QED regime with quantum link models."
    },
    {
        "anchor": "Study of the pion-mass dependence of $\u03c1$-meson properties in lattice\n  QCD: We collect spectra extracted in the $I=\\ell=1$ $\\pi\\pi$ sector provided by\nvarious lattice QCD collaborations and study the $m_\\pi$ dependence of\n$\\rho$-meson properties using Hamiltonian Effective Field Theory (HEFT). In\nthis unified analysis, the coupling constant and cutoff mass, characterizing\nthe $\\rho - \\pi \\pi$ vertex, are both found to be weakly dependent on $m_\\pi$,\nwhile the mass of the bare $\\rho$, associated with a simple quark-model state,\nshows a linear dependence on $m_\\pi^2$. Both the lattice results and\nexperimental data can be described well. Drawing on HEFT's ability to describe\nthe pion mass dependence of resonances in a single formalism, we map the\ndependence of the phase shift as a function of $m_\\pi$, and expose interesting\ndiscrepancies in contemporary lattice QCD results.",
        "positive": "Third moments of conserved charges in QCD phase diagram: We point out that the third moments of conserved charges, the baryon and\nelectric charge numbers, and energy, as well as their mixed moments, change\ntheir signs around the QCD phase boundary in the temperature and baryon\nchemical potential plane. These signs can be measured in relativistic heavy ion\ncollisions, and will give clear information on the phase structure of QCD and\nthe state of the system in the early stage of relativistic heavy ion\ncollisions. The behaviors of these moments on the temperature axis and at small\nquark chemical potential can be analyzed in lattice QCD simulations. We\nemphasize that the third moments obtained on the lattice, together with the\nexperimental results, will provide a deep understanding about the QCD phase\ndiagram and the location of the state created in heavy ion collisions."
    },
    {
        "anchor": "Simulations of $ SU(2) $ lattice gauge theory with dynamical reduced\n  staggered fermions: We simulate $ SU(2) $ lattice gauge theory using dynamical reduced staggered\nfermions. The latter lead to two rather than four Dirac fermions in the\ncontinuum limit. We review the derivation and properties of reduced staggered\nfermions and show that in the case of fields in the fundamental representation\nof $SU(2)$ the theory does not exhibit a sign problem and can be simulated\nusing the RHMC algorithm. We present results on lattices up to $16^4$ for a\nwide range of bare fermion masses. We find a single site condensate appears at\nstrong coupling that spontaneously breaks the one global $U(1)$ symmetry\nremaining in the reduced fermion action.",
        "positive": "Solving DWF Dirac Equation Using Multisplitting Preconditioned Conjugate\n  Gradient: We show that using the multisplitting algorithm as a preconditioner for\nconjugate gradient inversion of the domain wall fermion Dirac operator could\neffectively reduce the inter-node communication cost, at the expense of\nperforming more on-node floating point operations. This method could be useful\nfor supercomputers with far more on-node flops than inter-node communication\nbandwidth."
    },
    {
        "anchor": "Tricritical Behavior of Two-Dimensional Scalar Field Theories: We compute by Monte Carlo numerical simulations the critical exponents of\ntwo-dimensional scalar field theories at the $\\lambda\\phi^6$ tricritical point.\nThe results are in agreement with the Zamolodchikov conjecture based on\nconformal invariance.",
        "positive": "Doubly Charmed Tetraquark $T^+_{cc}$ from Lattice QCD near Physical\n  Point: The doubly charmed tetraquark $T^+_{cc}$ recently discovered by the LHCb\nCollaboration is studied on the basis of $(2+1)$-flavor lattice QCD simulations\nof the $D^*D$ system with nearly physical pion mass $m_\\pi=146$ MeV. The\ninteraction of $D^*D$ in the isoscalar and $S$-wave channel, derived from the\nhadronic spacetime correlation by the HAL QCD method, is attractive for all\ndistances and leads to a near-threshold virtual state with a pole position\n$E_\\text{pole}=-59\\left(^{+53}_{-99}\\right)\\left(^{+2}_{-67}\\right)$ keV and a\nlarge scattering length $1/a_0=0.05(5)\\left(^{+2}_{-2}\\right)~\\text{fm}^{-1}$.\nThe virtual state is shown to evolve into a loosely bound state as $m_\\pi$\ndecreases to its physical value by using a potential modified to $m_\\pi=135$\nMeV based on the pion-exchange interaction. Such a potential is found to give a\nsemiquantitative description of the LHCb data on the $D^0D^0\\pi^+$ mass\nspectrum. Future study is necessary to perform physical-point simulations with\nthe isospin-breaking and open three-body-channel effects taken into account."
    },
    {
        "anchor": "Meson-meson interactions -- from static to dynamic valence quarks: A method for the extraction of an effective meson-meson potential from Green\nfunctions, which can be obtained from a lattice simulation, is presented.\nSimulations are carried out for compact QED and QCD in four dimensions using\nthe quenched approximation and the hopping parameter expansion. In a further\nstudy, a heavy-light meson is considered employing a conjugate gradient\nalgorithm for the light propagators. Due to the Pauli exclusion principle, the\nresults for QED indicate the existence of a hard core, but for QCD there is\nstrong attraction at small meson distances.",
        "positive": "The status of US Teraflops-scale projects: The current status of United States projects pursuing Teraflops-scale\ncomputing resources for lattice field theory is discussed. Two projects are in\nexistence at this time: the Multidisciplinary Teraflops Project, incorporating\nthe physicists of the QCD Teraflops Collaboration, and a smaller project,\ncentered at Columbia, involving the design and construction of a 0.8 Teraflops\ncomputer primarily for QCD."
    },
    {
        "anchor": "Analysis of unstable particle with the maximum entropy method in O(4)\n  $\u03c6^4$ theory on the lattice: We explore applications of the maximum entropy method (MEM) to determine\nproperties of unstable particles using the four-dimensional O(4) $\\phi^4$\ntheory as a laboratory. The spectral function of the correlation function of\nthe unstable $\\sigma$ particle is calculated with MEM, and shown to yield\nreliable results for both the mass of $\\sigma$ and the energy of the two-pion\nstate. Calculations are also made for the case in which $\\sigma$ is stable.\nDistinctive differences in the volume dependence of the $\\sigma$ mass and\ntwo-pion energy for the stable and unstable cases are analyzed in terms of\nperturbation theory.",
        "positive": "A novel approach to nonperturbative renormalization of singlet and\n  nonsinglet lattice operators: A novel method for nonperturbative renormalization of lattice operators is\nintroduced, which lends itself to the calculation of renormalization factors\nfor nonsinglet as well as singlet operators. The method is based on the\nFeynman-Hellmann relation, and involves computing two-point correlators in the\npresence of generalized background fields arising from introducing additional\noperators into the action. As a first application, and test of the method, we\ncompute the renormalization factors of the axial vector current $A_\\mu$ and the\nscalar density $S$ for both nonsinglet and singlet operators for $N_f=3$\nflavors of SLiNC fermions. For nonsinglet operators, where a meaningful\ncomparison is possible, perfect agreement with recent calculations using\nstandard three-point function techniques is found."
    },
    {
        "anchor": "Spin and Gauge Systems on Spherical Lattices: We present results for 2D and 4D systems on lattices with topology homotopic\nto the surface of a (hyper) sphere $S^2$ or $S^4$. Finite size scaling is\nstudied in situations with phase transitions of first and second order type.\nThe Ising and Potts models exhibit the expected behaviour; for the 4D pure\ngauge $U(1)$ theory we find consistent scaling indicative of a second order\nphase transition with critical exponent $\\nu\\simeq 0.36(1)$.",
        "positive": "How the PHMC algorithm samples configuration space: We show that in practical simulations of lattice QCD with two dynamical light\nfermion species the PHMC algorithm samples configuration space differently from\nthe commonly used HMC algorithm."
    },
    {
        "anchor": "The chiral phase transition from strong to weak coupling: The order of the chiral phase transition of lattice QCD with unimproved\nstaggered fermions is known to depend on the number of quark flavours, their\nmasses and the lattice spacing. Previous studies in the literature for $N_f \\in\n\\{ 3,4 \\}$ show first-order transitions, which weaken with decreasing lattice\nspacing. Here we investigate what happens when lattices are made coarser to\nestablish contact to the strong coupling region. For $N_f \\in \\{4,8 \\}$ we find\na drastic weakening of the transition when going from $N_{\\tau}=4$ to\n$N_{\\tau}=2$, which is consistent with a second-order chiral transition\nreported in the literature for $N_f=4$ in the strong coupling limit. This\nimplies a non-monotonic behaviour of the critical quark or pseudo-scalar meson\nmass, which separates first-order transitions from crossover behaviour, as a\nfunction of lattice spacing.",
        "positive": "Glueball matrix elements: a lattice calculation and applications: We compute the matrix elements of the energy-momentum tensor between glueball\nstates and the vacuum in SU(3) lattice gauge theory and extrapolate them to the\ncontinuum. These matrix elements may play an important phenomenological role in\nidentifying glue-rich mesons. Based on a relation derived long ago by the ITEP\ngroup for J/psi radiative decays, the scalar matrix element leads to a\nbranching ratio for the glueball that is at least three times larger than the\nexperimentally observed branching ratio for the f_0 mesons above 1GeV. This\nsuggests that the glueball component must be diluted quite strongly among the\nknown scalar mesons. Finally we review the current best continuum determination\nof the scalar and tensor glueball masses, the deconfining temperature, the\nstring tension and the Lambda parameter, all in units of the Sommer reference\nscale, using calculations based on the Wilson action."
    },
    {
        "anchor": "Quenched Spectroscopy for the N=1 Super-Yang-Mills Theory: We present results for the Quenched SU(2) N=1 Super-Yang-Mills spectrum at\n$\\beta=2.6$, on a $V=16^3 \\times 32$ lattice, in the OZI approximation. This is\na first step towards the understanding of the chiral limit of lattice N=1 SUSY.",
        "positive": "Non-perturbative improvement of the vector current in Wilson lattice QCD: Many observables of interest in lattice QCD are extracted from correlation\nfunctions involving the vector current. If Wilson fermions are used, it is\ntherefore of practical importance that, besides the action, the current be\nO($a$) improved in order to remove the leading discretization errors from the\nobservables. Here we introduce and apply a new method to determine the\nimprovement coefficient for the two most widely used discretizations of the\ncurrent."
    },
    {
        "anchor": "Testing fixed points in the 2D O(3) non-linear sigma model: Using high statistic numerical results we investigate the properties of the\nO(3) non-linear 2D sigma-model. Our main concern is the detection of an\nhypothetical Kosterlitz-Thouless-like (KT) phase transition which would\ncontradict the asymptotic freedom scenario. Our results do not support such a\nKT-like phase transition.",
        "positive": "On the Higgs-Confinement Complementarity: It has been noticed long ago that in Higgs models with `complete symmetry\nbreaking' one can move from the confinement to the Higgs regime without\ncrossing a phase boundary, a fact sometimes called referred to as\n`complementarity'. In a recent paper some doubt was raised about the\ncorrectness of the mathematics underlying this fact and it was claimed that the\nsupposed `flaw' would resolve the `paradox' seen in this complementarity. Here\nwe briefly revisit the facts both from a mathematical and a physical point of\nview and point out that (a) there is no paradox and (b) there is no flaw in the\nmathematical reasoning."
    },
    {
        "anchor": "Strangeonium-like hybrids on the lattice: The strangeonium-like $s\\bar{s}g$ hybrids are investigated from lattice QCD\nin the quenched approximation. In the Coulomb gauge, spatially extended\noperators are constructed for $1^{--}$ and $(0,1,2)^{-+}$ states with the color\noctet $s\\bar{s}$ component being separated from the chromomagnetic field\nstrength by spatial distances $r$, whose matrix elements between the vacuum and\nthe corresponding states are interpreted as Bethe-Salpeter (BS) wave functions.\nIn each of the $(1,2)^{-+}$ channels, the masses and the BS wave functions are\nreliably derived. The $1^{-+}$ ground state mass is around 2.1-2.2 GeV, and\nthat of $2^{-+}$ is around 2.3-2.4 GeV, while the masses of the first excited\nstates are roughly 1.4 GeV higher. This mass splitting is much larger than the\nexpectation of the phenomenological flux-tube model or constituent gluon model\nfor hybrids, which is usually a few hundred MeV. The BS wave functions with\nrespect to $r$ show clear radial nodal structures of non-relativistic two-body\nsystem, which imply that $r$ is a meaningful dynamical variable for these\nhybrids and motivate a color halo picture of hybrids that the color octet\n$s\\bar{s}$ is surrounded by gluonic degrees of freedom. In the $1^{--}$\nchannel, the properties of the lowest two states comply with those of\n$\\phi(1020)$ and $\\phi(1680)$. We have not obtained convincing information\nrelevant to $\\phi(2170)$ yet, however, we argue that whether $\\phi(2170)$ is a\nconventional $s\\bar{s}$ meson or a $s\\bar{s}g$ hybrid within the color halo\nscenario, the ratio of partial decay widths $\\Gamma(\\phi \\eta)$ and $\\Gamma\n(\\phi \\eta')$ observed by BESIII can be understood by the mechanism of hadronic\ntransition of a strangeonium-like meson along with the $\\eta-\\eta'$ mixing.",
        "positive": "Equation of state for pure SU(3) gauge theory on anisotropic lattices: We present results for the equation of state for pure SU(3) gauge theory\nobtained on anisotropic lattices with the anisotropy $\\xi \\equiv a_s/a_t = 2$.\nThe pressure and energy density are calculated on $N_t / \\xi = 4, 5$ and 6\nlattices with the integral method. They are found to satisfy the leading\n$1/N_t^2$ scaling from our coarsest lattice $N_t/\\xi=4$. This enables us to\ncarry out well controlled continuum extrapolations. We find that the pressure\nand energy density agree with those obtained using the isotropic plaquette\naction, but have smaller and more reliable errors."
    },
    {
        "anchor": "The 3d O(4) model as an effective approach to the QCD phase diagram: The QCD phase diagram is one of the most prominent outstanding puzzles within\nthe Standard Model. Various experiments, which aim at its exploration beyond\nsmall baryon density, are operating or in preparation. From the theoretical\nside, this is an issue of non-perturbative QCD, and therefore of lattice\nsimulations. However, a finite baryon density entails a technical problem\n(known as the ``sign problem''), which has not been overcome so far. Here we\npresent a study of an effective theory, the O(4) non-linear sigma model. It\nperforms spontaneous symmetry breaking with the same Lie group structure as\n2-flavor QCD in the chiral limit, which strongly suggests that they belong to\nthe same universality class. Since we are interested in high temperature, we\nfurther assume dimensional reduction to the 3d O(4) model, which implies\ntopological sectors. As pointed out by Skyrme, Wilczek and others, its\ntopological charge takes the r\\^{o}le of the baryon number. Hence the baryon\nchemical potential $\\mu_{B}$ appears as an imaginary vacuum angle, which can be\nincluded in the lattice simulation without any sign problem. We present\nnumerical results for the critical line in the chiral limit, and for the\ncrossover in the presence of light quark masses. Their shapes are compatible\nwith other predictions, but up to the value of about $\\mu_{B} \\approx 300~{\\rm\nMeV}$ we do not find the notorious Critical Endpoint (CEP).",
        "positive": "Status of the QPACE Project: We give an overview of the QPACE project, which is pursuing the development\nof a massively parallel, scalable supercomputer for LQCD. The machine is a\nthree-dimensional torus of identical processing nodes, based on the PowerXCell\n8i processor. The nodes are connected by an FPGA-based, application-optimized\nnetwork processor attached to the PowerXCell 8i processor. We present a\nperformance analysis of lattice QCD codes on QPACE and corresponding hardware\nbenchmarks."
    },
    {
        "anchor": "Progress in calculation of the fourth Mellin moment of the pion\n  light-cone distribution amplitude using the HOPE method: The pion light-cone distribution amplitude (LCDA) is a central\nnon-perturbative object of interest for the calculation of high-energy\nexclusive processes in quantum chromodynamics. This article describes the\nprogress in the lattice QCD calculation of the fourth Mellin moment of the pion\nLCDA using a heavy-quark operator product expansion (HOPE).",
        "positive": "Scalar correlators near the 3-flavor thermal critical point: We investigate screening masses at both sides of the first order finite\ntemperature transition with 3 quark flavors using the nonperturbatively\nimproved clover fermion action and the Iwasaki gauge action. We have developed\nthe method of hierarchical truncations with stochastic probing to accelerate\nthe noise estimator for evaluating quark loops at every spatial lattice slices.\nAt parameter values we study, the flavor singlet scalar meson has a screening\nmass about half of the pion screening mass. It becomes lighter as the system\napproaches the critical endpoint."
    },
    {
        "anchor": "Gauge-fixing approach to lattice chiral gauge theories: We review the status of our recent work on the gauge-fixing approach to\nlattice chiral gauge theories. New numerical results in the reduced version of\na model with a U(1) gauge symmetry are presented which strongly indicate that\nthe factorization of the correlation functions of the left-handed neutral and\nright-handed charged fermion fields, which we established before in\nperturbation theory, holds also nonperturbatively.",
        "positive": "Charm Current-Current Correlators in Twisted Mass Lattice QCD: The current correlator method has been shown to be a practical tool to\nextract the charm quark mass and strong coupling constant from Lattice QCD data\nas an alternative to the sum rule approach using experimental electron-positron\nannihilation cross section data. We report on the progress of an investigation\nof charm current-current correlators in N_f=2 Twisted Mass Lattice QCD. Upon\ndetermining the temporal moments of the current correlators we compare to the\nlow-energy expansion of the moments in perturbative QCD and calculate the charm\nquark mass and strong coupling constant and in case of the vector current\ncorrelator directly compare both methods."
    },
    {
        "anchor": "Hadron Properties in the Vicinity of $T_c$: Modifications of hadron masses and some of their basic properties with\ntemperature or nuclear density are considered as one possible signature for the\nformation of dense hadronic matter in nuclear collisions. We discuss here some\nbasic results on the temperature dependence of hadron properties obtained from\ncalculations of hadron correlation functions, the chiral condensate as well as\nthe equation of state in finite temperature lattice QCD.",
        "positive": "Determining the conformal window: SU(2) gauge theory with N_f = 4, 6 and\n  10 fermion flavours: We study the evolution of the coupling in SU(2) gauge field theory with\n$N_f=4$, 6 and 10 fundamental fermion flavours on the lattice. These values are\nchosen close to the expected edges of the conformal window, where the theory\npossesses an infrared fixed point. We use improved Wilson-clover action, and\nmeasure the coupling in the Schr\\\"odinger functional scheme. At four flavours\nwe observe that the couping grows towards the infrared, implying QCD-like\nbehaviour, whereas at ten flavours the results are compatible with a Banks-Zaks\ntype infrared fixed point. The six flavour case remains inconclusive: the\nevolution of the coupling is seen to become slower at the infrared, but the\naccuracy of the results falls short from fully resolving the fate of the\ncoupling. We also measure the mass anomalous dimension for the $N_f=6$ case."
    },
    {
        "anchor": "Chiral symmetry on the lattice: As a non-perturbative and gauge invariant regularization the lattice provides\na tool for deeper understanding of the celebrated Yang-Mills theory, QCD and\nchiral gauge theories. For illustration, I discuss some analytic developments\non the lattice related to chiral symmetry, chiral fermions and improvement\nprograms. Chiral symmetry on the lattice has an amazing history, and it might\ninfluence our perception of a symmetry beyond this example.",
        "positive": "Progress in understanding confinement: A few aspects of the mechanism of confinement of color by monopole\ncondensation are reviewed."
    },
    {
        "anchor": "Development in Lattice QCD: After a brief discussion of the promise and limitations of the lattice\ntechnique, I review lattice QCD results for several quantities of\nphenomenological interest. These are: matrix elements for heavy-to-light meson\ndecays, leptonic decay constants f_B and f_D, the parameters B_B and B_K for\nneutral B and K meson mixing respectively, the strong coupling constant, light\nquark masses and the lightest scalar glueball mass.",
        "positive": "Lattice calculation for unitary fermions in a finite box: A fundamental constant in systems of unitary fermions is the so-called\nBertsch parameter, the ratio of the ground state energy for spin paired unitary\nfermions to that for free fermions at the same density. I discuss how we\ncomputed this parameter as well as the pairing gap using a recently developed\nlattice construction for unitary fermions, by measuring correlation functions\nfor up to 38 fermions in a finite box. Our calculation illustrates interesting\nissues facing the study of many-body states on the lattice, which may\neventually be confronted in QCD calculations as well."
    },
    {
        "anchor": "Lines of Constant Physics in a Five-Dimensional Gauge-Higgs Unification\n  Scenario: We report on the progress in the study of a five-dimensional SU(2)\nGauge-Higgs Unification model. In this non-perturbative study, the Higgs\nmechanism is triggered by the spontaneous breaking of a global symmetry. In the\nsame region of the phase diagram, we observe both dimensional reduction and the\nratio of Higgs and Z boson masses to take the value known from experiment. We\npresent the first results on the construction of a line of constant physics in\nthis region, including the prediction for the mass scale of the first excited\nstates of the Higgs and gauge bosons.",
        "positive": "QCD Anderson transition with overlap valence quarks on a twisted-mass\n  sea: In this work we probe the QCD Anderson transition by studying spectral\ndistributions of the massless overlap operator on gauge configurations created\nby the twisted mass at finite temperature collaboration (tmfT) with 2+1+1\nflavors of dynamical quarks and the Iwasaki gauge action. We assess finite-size\nand discretization effects by considering two different lattice spacings and\nseveral physical volumes, and mimic the approach to the continuum limit through\nstereographic projection. Fitting the inflection points of the participation\nratios of the overlap Dirac eigenmodes, we obtain estimates of the temperature\ndependence of the mobility edge, below which quark modes are localized. We\nobserve that it is well-described by a quadradic polynomial and systematically\nvanishes at temperatures below the pseudo-critical one of the chiral\ntransition. In fact, our best estimates within errors overlap with that of the\nchiral phase transition temperature of QCD in the chiral limit."
    },
    {
        "anchor": "Square Gravity: We simulate the Ising model on dynamical quadrangulations using a\ngeneralization of the flip move for triangulations with two aims: firstly, as a\nconfirmation of the universality of the KPZ/DDK exponents of the Ising phase\ntransition, worthwhile in view of some recent surprises with other sorts of\ndynamical lattices; secondly, to investigate the transition of the Ising\nantiferromagnet on a dynamical loosely packed (bipartite) lattice. In the\nlatter case we show that it is still possible to define a staggered\nmagnetization and observe the antiferromagnetic analogue of the transition.",
        "positive": "Phase Structure of Lattice N=4 Super Yang-Mills: We make a first study of the phase diagram of four-dimensional N=4 super\nYang-Mills theory regulated on a space-time lattice. The lattice formulation we\nemploy is both gauge invariant and retains at all lattice spacings one exactly\npreserved supersymmetry charge. Our numerical results are consistent with the\nexistence of a single deconfined phase at all observed values of the bare\ncoupling."
    },
    {
        "anchor": "Lattice QCD predictions for shapes of event distributions along the\n  freezeout curve in heavy-ion collisions: We present lattice QCD results along the freezeout curve of heavy-ion\ncollisions for the ongoing RHIC energy scan as well as the LHC heavy-ion runs\nplanned for this year. The skew and kurtosis of the event distribution of\nbaryon number are positive at all energies studied, We predict three ratios of\nnon-linear susceptibilities along the freezeout curve as functions of the\ncolliding energy, Sqrt[S_{NN}]. They have smooth behaviour except in the\nvicinity of a critical point; this can have multiple benefits.",
        "positive": "Excitations of isolated static charges in the charge $q=2$ abelian Higgs\n  model: We present lattice Monte Carlo evidence of stable excitations of isolated\nstatic charges in the Higgs phase of the charge $q=2$ abelian Higgs model.\nThese localized excitations are excited states of the interacting fields\nsurrounding the static charges. Since the $q=2$ abelian Higgs model is a\nrelativistic version of the Landau-Ginzburg effective action of a\nsuperconductor, we conjecture that excited states of this kind might be\nrelevant in a condensed matter context. Taken together with recent related work\nin SU(3) gauge Higgs theory, our result suggests that a massive fermion\nexcitation spectrum may be a general feature of gauge Higgs theories."
    },
    {
        "anchor": "The QCD EoS from simulations on BlueGene L Supercomputers at LLNL and\n  NYBlue: We present results for the QCD Equation of State (EoS) obtained using\nsimulations of lattice QCD at zero chemical potential. Our high statistics\nresults compare improved asqtad and p4fat3 staggered quarks on lattices with a\ntemporal extent N_tau = 6 and 8 and light quark masses approximately one fifth\nand one tenth the strange quark mass. We find that the two actions give\nconsistent results and estimate that the trace anomaly (epsilon - 3p)/T^4\nobtained on N_tau = 8 lattices represents the continuum value to better than\n20% uncertainty over the temperature range 140-700 MeV. The precision in the\nestimates of energy density and pressure are better, therefore, we conclude\nthat lattice estimates of the energy density and pressure should be used in the\nphenomenological analysis of RHIC and LHC data. We also find a consistent\npicture of the crossover temperature from all observables studied, with the\nbest estimated range to be 185-195 MeV. These calculations are being carried\nout on the IBM BlueGene/L supercomputer at Lawrence Livermore National\nLaboratory and at the New York Center for Computational Science (NYBlue).",
        "positive": "Fast K System Generators of Pseudorandom Numbers: We suggest fast algorithm for the matrix generator of pseudorandom numbers\nbased on Kolmogorov-Anosov K systems which has been proposed earlier. This\nalgorithm reduces $N^{2}$ operation of the matrix generator to $NlnN$ and\nessentially reduces the generation time. It also clarifies the algebraic\nstructure of this type of K system generators."
    },
    {
        "anchor": "Bit Level Correlations in Some Pseudorandom Number Generators: We present results of extensive bit level tests on some pseudorandom number\ngenerators which are commonly used in physics applications. The generators have\nfirst been tested with an extended version of the $d$-tuple test. Second, we\nhave developed a novel {\\it cluster test} where a physical analogy of the\nbinary numbers with the two dimensional Ising model has been utilized. We\ndemonstrate that the new test is rather powerful in finding periodic\ncorrelations on bit level. Results of both test methods are presented for each\nbit of the output of the generators. Some generators exhibit clear bit level\ncorrelations but we find no evidence of discernible correlations for\ngenerators, which have recently produced systematic errors in Monte Carlo\nsimulations.",
        "positive": "Gluon 2- and 3-Point Correlation Functions on the Lattice: I present some preliminary results, obtained in collaboration with C. Bernard\nand A. Soni, for the lattice evaluation of 2- and 3-point gluon correlation\nfunctions in momentum space, with emphasis on the amputated 3-gluon vertex\nfunction. The final goal of this approach is the study of the running QCD\ncoupling constant as defined from the amputated 3-gluon vertex."
    },
    {
        "anchor": "Pion Valence Quark Distribution from Matrix Element Calculated in\n  Lattice QCD: We present the first exploratory lattice QCD calculation of the pion valence\nquark distribution extracted from spatially separated current-current\ncorrelations in coordinate space. We show that an antisymmetric combination of\nvector and axial-vector currents provides direct information on the pion\nvalence quark distribution. Using the collinear factorization approach, we\ncalculate the perturbative tree-level kernel for this current combination and\nextract the pion valence distribution. The main goal of this article is to\ndemonstrate the efficacy of this general lattice QCD approach in the reliable\nextraction of parton distributions. With controllable power corrections and a\ngood understanding of the lattice systematics, this method has the potential to\nserve as a complementary to the many efforts to extract parton distributions in\nglobal analyses from experimentally measured cross sections. We perform our\ncalculation on an ensemble of 2+1 flavor QCD using the isotropic-clover fermion\naction, with lattice dimensions $32^3\\times 96$ at a lattice spacing\n\\mbox{$a=0.127$ fm} and the quark mass equivalent to a pion mass $m_\\pi \\simeq\n416$ MeV.",
        "positive": "String effects in the 3d gauge Ising model: We compare the predictions of the effective string description of confinement\nwith a set of Montecarlo data for the 3d gauge Ising model at finite\ntemperature. Thanks to a new algorithm which makes use of the dual symmetry of\nthe model we can reach very high precisions even for large quark-antiquark\ndistances. We are thus able to explore the large R regime of the effective\nstring. We find that for large enough distances and low enough temperature the\ndata are well described by a pure bosonic string. As the temperature increases\nhigher order corrections become important and cannot be neglected even at large\ndistances. These higher order corrections seem to be well described by the\nNambu-Goto action truncated at the first perturbative order."
    },
    {
        "anchor": "Strong coupling analysis of the large-N 2-d lattice chiral models: Two dimensional large-N chiral models on the square and honeycomb lattices\nare investigated by a strong coupling analysis. Strong coupling expansion turns\nout to be predictive for the evaluation of continuum physical quantities, to\nthe point of showing asymptotic scaling. Indeed in the strong coupling region a\nquite large range of beta values exists where the fundamental mass agrees,\nwithin about 5% on the square lattice and about 10% on the honeycomb lattice,\nwith the continuum predictions in the %%energy scheme.",
        "positive": "Variants of fattening and flavor symmetry restoration: We study the effects of different \"fat link\" actions for Kogut-Susskind\nquarks on flavor symmetry breaking. Our method is mostly empirical - we compute\nthe pion spectrum with different valence quark actions on common sets of sample\nlattices. Different actions are compared, as best we can, at equivalent\nphysical points. We find significant reductions in flavor symmetry breaking\nrelative to the conventional or to the \"link plus staple\" actions, with a\nreasonable cost in computer time. We also develop and test a scheme for\napproximate unitarization of the fat links. While our tests have concentrated\non the valence quark action, our results will be useful in designing\nsimulations with dynamical quarks."
    },
    {
        "anchor": "Microscopic Spectral Density of the Dirac Operator in Quenched QCD: Measurements of the lowest-lying eigenvalues of the staggered fermion Dirac\noperator are made on ensembles of equilibrium gauge field configurations in\nquenched SU(3) lattice gauge theory. The results are compared with exact\nanalytical predictions in the microscopic finite-volume scaling regime.",
        "positive": "Large-scale computation of the exponentially expanding universe in a\n  simplified Lorentzian type IIB matrix model: The type IIB matrix model is a conjectured nonperturbative formulation of\nsuperstring theory. Recent studies on the Lorentzian version of the model have\nshown that only three out of nine spatial directions start to expand after some\ncritical time. On the other hand, due to the unbounded action of the Lorentzian\nmodel, one has to introduce infrared (IR) cutoffs in order to make the\npartition function finite. In this work we investigate whether the effects of\nthe IR cutoffs disappear in the infinite volume limit. For that purpose, we\nstudy a simplified model with large matrix size up to $N=256$ by Monte Carlo\nsimulation. First we confirm the exponentially expanding behavior of the\n\"universe\". Then we generalize the form of the IR cutoffs by one parameter, and\nfind that the results become universal in some region of the parameter. It is\nsuggested that the effects of IR cutoffs disappear in this region, which is\nconfirmed also from the studies of Schwinger-Dyson equations."
    },
    {
        "anchor": "Confinement and the vortex vacuum of SU(2) lattice gauge theory: The vortex theory which emerges from SU(2) lattice gauge theory by center\nprojection is briefly reviewed. In this vortex picture, quark confinement is\ndue to percolating (closed) vortices which are randomly linked to the Wilson\nloop. The deconfinement phase transition appears as a de-percolation phase\ntransition.",
        "positive": "Speeding up Domain Wall Fermion Algorithms using QCDLAB: Simulating lattice QCD with chiral fermions and indeed using Domain Wall\nFermions continues to be challenging project however large are concurrent\ncomputers. One obvious bottleneck is the slow pace of prototyping using the low\nlevel coding which prevails in most, if not all, lattice projects. Recently, we\ncame up with a new proposal, namely QCDLAB, a high level language interface,\nwhich we believe will boost our endeavours to rapidly code lattice prototype\napplications in lattice QCD using MATLAB/OCTAVE language and environment. The\nfirst version of the software, QCDLAB 1.0 offers the general framework on how\nto achieve this goal by simulating set of the lattice Schwinger model {\\tt\nhttp://phys.fshn.edu.al/qcdlab.html}. In this talk we introduce QCDLAB 1.1,\nwhich extends QCDLAB 1.0 capabilities for real world lattice computations with\nWilson and Domain Wall fermions."
    },
    {
        "anchor": "Improved Measure of Local Chirality: It is popular to probe the structure of the QCD vacuum indirectly by studying\nindividual fermion eigenmodes, because this provides a natural way to filter\nout UV fluctuations. The double-peaking in the distribution of the local chiral\norientation parameter (X) has been offered as evidence, by some, in support of\na particular model of the vacuum. Here we caution that the X-distribution\npeaking varies significantly with various versions of the definition of X.\nFurthermore, each distribution varies little from that resulting from a random\nreshuffling of the left-handed (and independently the right-handed) fields,\nwhich destroys any QCD-induced left-right correlation; that is, the\ndouble-peaking is mostly a phase-space effect. We propose a new universal\ndefinition of the X parameter whose distribution is uniform for randomly\nreshuffled fields. Any deviations from uniformity for actual data can then be\ndirectly attributable to QCD-induced dynamics. We find that the familiar double\npeak disappears.",
        "positive": "The $I=1$, $J=1$ channel of the O(4) $\u03bb\u03c6^4_4$ theory: A Monte Carlo simulation of the $O(4)$ $\\lambda \\phi^4$ theory in the broken\nphase is performed on a hypercubic lattice in search of an $I=1$, $J=1$\nresonance. We investigate the region of the cutoff theory where the interaction\nis strong as it is there that a resonance would be expected to have a better\nchance to form. In that region the presence of an $I=1$, $J=1$ resonance with\nmass below the cutoff is excluded. NOTE: The full ps file is also available via\nanonymous ftp to ftp.scri.fsu.edu. To get the ps file, ftp to this address and\nuse for username \"anonymous\" and for password your name. The file is in the\ndirectory pub/vranas (to go to that directory type: cd pub/vranas) and is\ncalled lat92_proc_rho.ps (to get it type: get lat92_proc_rho.ps)"
    },
    {
        "anchor": "The Critical Mass of Wilson Fermions: A Comparison of Perturbative and\n  Monte Carlo Results: We calculate the critical value of the hopping parameter, $\\kappa_c$, in\nLattice QCD with Wilson fermions, to two loops in perturbation theory.\n  This quantity is an additive renormalization; as such, it is characterized\nnot only by the standard caveats regarding the asymptotic nature of\nperturbative results, but also by a linear divergence in the lattice spacing.\nConsequently, our calculation tests rather stringently the limits of\napplicability of perturbation theory.\n  We compare our results to non perturbative evaluations of $\\kappa_c$ coming\nfrom Monte Carlo simulations.\n  Finally, we apply a tadpole improvement technique on our results; this shifts\nthem quite favourably towards the non perturbative values.",
        "positive": "Single site model of large N gauge theories coupled to adjoint fermions: We consider a single site large N gauge theory coupled to adjoint fermions at\nweak coupling. We study the distribution of the eigenvalues of the link\nvariables using a four-dimensional density function. We show that it is\npossible to recover the infinite-volume continuum limit for a certain range of\nfermion flavors if we use fermions with a bare mass of zero."
    },
    {
        "anchor": "Derivation of Chiral Lagrangians from Random Lattice QCD: In our work we extend the ideas of the derivation of the chiral effective\ntheory from the lattice QCD [1] to the case of the random lattice\nregularization of QCD. Such procedure allows in principle to find contribution\nof any order into the chiral effective lagrangian. It is shown that an infinite\nsubseries of the chiral perturbation can be summed up into tne Born-Infeld term\nand the logarithmic correction to them.",
        "positive": "Finite-size scaling and deconfinement transition: the case of 4D SU(2)\n  pure gauge theory: A recently introduced method for determining the critical indices of the\ndeconfinement transition in gauge theories, already tested for the case of 3D\nSU(3) pure gauge theory, is applied here to 4D SU(2) pure gauge theory. The\nmethod is inspired by universality and based on the finite size scaling\nbehavior of the expectation value of simple lattice operators, such as the\nplaquette. We obtain an accurate determination of the critical index $\\nu$, in\nagreement with the prediction of the Svetitsky-Yaffe conjecture."
    },
    {
        "anchor": "Pion Scattering in Wilson Chiral Perturbation Theory: We compute the scattering amplitude in Wilson Chiral Perturbation Theory for\ntwo flavors. The lattice spacing effects due to the explicit chiral symmetry\nbreaking are kept through O(a^2), and we consider the regime where the quark\nmass m is of order a^2 Lambda_^3. Analytic expressions for the scattering\nlengths in different isospin channels are given. As a result of the O(a^2)\nterms the scattering lengths do not vanish in the chiral limit. Moreover,\nadditional chiral logarithms proportional to a^2 ln M_pi^2 are present in the\none-loop results. These contributions can obscure the continuum chiral\nlogarithms and the determination of low-energy constants from numerical lattice\nsimulations.",
        "positive": "A lattice study of $\u039b_b$ semileptonic decay: We present results from a lattice study of the semileptonic decay $\\Lambda_b\n\\to \\Lambda_c l \\nu_l $. We use $O(a^2, \\alpha_s a^2)$ improved quenched\nlattices of the MILC collaboration, with lattice spacing $\\sim 0.13$ fm. For\nthe valence quarks, the tadpole-improved clover action is used, with the\nFermilab method employed for the heavy quarks. Form factors are extracted from\nthe vector as well as the axial-vector part of the current."
    },
    {
        "anchor": "Theoretical Bounds on New Four-Fermion Interactions and TeV Scale\n  Physics: The standard model weak interactions can be described by four-fermion V-A\noperators at low energies. New physics at the TeV scale can, however, generate\nthe other Lorentz structures. In this talk, we review the constraints on such\ninteractions from nuclear and hadronic decays, as well as from collider\nsearches. Currently the most stringent bounds come from the analysis of the 0+\nto 0+ nuclear and the pi to e nu gamma radiative pion decays. In the near\nfuture, the ultracold neutron beta decay experiments and the direct LHC\nmeasurements will compete in setting the most stringent bounds, provided,\nhowever, that the neutron-to-proton non-perturbative transition matrix elements\ncan be calculated to a level of 10-20% accuracy.",
        "positive": "Resolving Exceptional Configurations in Quenched Lattice QCD: Quenched lattice QCD calculations with Wilson-type fermions at small quark\nmasses are impeded by exceptional configurations. We show how this problem can\nbe resolved in a practicable way without changing the physics in the chiral\nlimit."
    },
    {
        "anchor": "An estimate of the hadronic vacuum polarization disconnected\n  contribution to the anomalous magnetic moment of the muon from lattice QCD: The quark-line disconnected diagram is a potentially important ingredient in\nlattice QCD calculations of the hadronic vacuum polarization contribution to\nthe anomalous magnetic moment of the muon. It is also a notoriously difficult\none to evaluate. Here, for the first time, we give an estimate of this\ncontribution based on lattice QCD results that have a statistically significant\nsignal, albeit at one value of the lattice spacing and an unphysically heavy\nvalue of the $u/d$ quark mass. We use HPQCD's method of determining the\nanomalous magnetic moment by reconstructing the Adler function from\ntime-moments of the current-current correlator at zero spatial momentum. Our\nresults lead to a total (including $u$, $d$ and $s$ quarks) quark-line\ndisconnected contribution to $a_{\\mu}$ of $-0.15\\%$ of the $u/d$ hadronic\nvacuum polarization contribution with an uncertainty which is 1\\% of that\ncontribution.",
        "positive": "Dual Abrikosov vortices in U(1) and SU(2) lattice gauge theories: The spatial distribution of fields and currents in confining theories can\ngive direct evidence of dual superconductivity. We review the behavior of\nvortices in the lattice Higgs effective theory. We discuss the techniques for\nfinding these properties and calculating the superconductivity parameters in\nlattice simulations. We have seen dual Abrikosov vortices directly in pure U(1)\nand SU(2) and others have also seen them in SU(3). We review the duality\ntransformation for U(1) in order to connect the U(1) results to a dual Higgs\ntheory.\n  In the non-Abelian cases the system appears to be near the borderline between\ntype I and II. We also discuss the response of the persistent currents to\nexternal fields."
    },
    {
        "anchor": "Curvature of the chiral pseudo-critical line in QCD: We determine the curvature of the pseudo-critical line of strong interactions\nby means of numerical simulations at imaginary chemical potentials. We consider\n$N_f=2+1$ stout improved staggered fermions with physical quark masses and the\ntree level Symanzik gauge action, and explore two different sets of lattice\nspacings, corresponding to temporal extensions $N_t = 6$ and $N_t = 8$. Both\nthe renormalized chiral condensate and the renormalized chiral susceptibility\nare used to locate the transition. The determinations obtained from the two\nquantities are in good agreement, a preliminary continuum extrapolation yields\n$\\kappa = 0.013(2)(1)$. We also investigate the impact of a non-zero strange\nquark chemical potential and compare our results to previous determinations in\nthe literature, discussing the possible sources of systematic errors affecting\nthe various procedures.",
        "positive": "Topological Charge Distribution and $CP^1$ Model with $\u03b8$ Term: The two dimensional $CP^1$ model with $\\theta$ term is simulated. We compute\nthe topological charge distribution $P(Q)$ by employing the ``set method\" and\n``trial function method\", which are effective in the calculations for very wide\nrange of $Q$ and large volume. The distribution $P(Q)$ shows the Gaussian\nbehavior in the small $\\beta$ (inverse coupling constant) region and deviates\nfrom it in the large $\\beta$ region. The free energy and its moment are\ncalculated as a function of $\\theta$. For small $\\beta$, the partition function\nis given by the elliptic theta function, and the distribution of its zeros on\nthe complex $\\theta$ plane leads to the first order phase transition at\n$\\theta=\\pi$. In the large $\\beta$ region, on the other hand, this first order\nphase transition disappears, but definite conclusion concerning the transition\nis not reached due to large errors."
    },
    {
        "anchor": "Lattice QCD study for relation between confinement and chiral symmetry\n  breaking on temporally odd-number lattice: We investigate the contribution from each Dirac modes to the Polyakov loop\nbased on a gauge-invariant analytical relation connecting the Polyakov loop and\nthe Dirac modes on a temporally odd-number lattice, where the temporal lattice\nsize is odd, with the normal (nontwisted) periodic boundary condition. The\ndumping factor in the relation plays crucial role for the negligible\ncontribution of low-lying Dirac modes to the Polyakov loop. The zero-value of\nthe Polyakov loop in the confinement phase is due to the ``positive/negative\nsymmetry'' of the Dirac-mode contribution to the Polyakov loop. In the\ndeconfinement phase, there is no such symmetry.",
        "positive": "Physical Observables from Lattice QCD at Fixed Topology: Because present Monte Carol algorithms for lattice QCD may become trapped in\na given topological charge sector when one approaches the continuum limit, it\nis important to understand the effect of calculating at fixed topology. In this\nwork, we show that although the restriction to a fixed topological sector\nbecomes irrelevant in the infinite volume limit, it gives rise to\ncharacteristic finite size effects due to contributions from all\n$\\theta$-vacua. We calculate these effects and show how to extract physical\nresults from numerical data obtained at fixed topology."
    },
    {
        "anchor": "Deep Learning Beyond Lefschetz Thimbles: The generalized thimble method to treat field theories with sign problems\nrequires repeatedly solving the computationally-expensive holomorphic flow\nequations. We present a machine learning technique to bypass this problem. The\ncentral idea is to obtain a few field configurations via the flow equations to\ntrain a feed-forward neural network. The trained network defines a new manifold\nof integration which reduces the sign problem and can be rapidly sampled. We\npresent results for the $1+1$ dimensional Thirring model with Wilson fermions\non sizable lattices. In addition to the gain in speed, the parameterization of\nthe integration manifold we use avoids the \"trapping\" of Monte Carlo chains\nwhich plagues large-flow calculations, a considerable shortcoming of the\nprevious attempts.",
        "positive": "Nucleon axial and tensor charges with dynamical overlap quarks: We report on our calculation of the nucleon axial and tensor charges in\n2+1-flavor QCD with dynamical overlap quarks. Gauge ensembles are generated at\na single lattice spacing 0.12 fm and at a strange quark mass close to its\nphysical value. We employ the all-mode-averaging technique to calculate the\nrelevant nucleon correlation functions, and the disconnected quark loop is\nefficiently calculated by using the all-to-all quark propagator. We present our\npreliminary results for the isoscalar and isovector charges obtained at pion\nmasses $m_\\pi$ = 450 and 540 MeV."
    },
    {
        "anchor": "Fisher's zeros as boundary of renormalization group flows in complex\n  coupling spaces: We propose new methods to extend the renormalization group transformation to\ncomplex coupling spaces. We argue that the Fisher's zeros are located at the\nboundary of the complex basin of attraction of infra-red fixed points. We\nsupport this picture with numerical calculations at finite volume for\ntwo-dimensional O(N) models in the large-N limit and the hierarchical Ising\nmodel. We present numerical evidence that, as the volume increases, the\nFisher's zeros of 4-dimensional pure gauge SU(2) lattice gauge theory with a\nWilson action, stabilize at a distance larger than 0.15 from the real axis in\nthe complex beta=4/g^2 plane. We discuss the implications for proofs of\nconfinement and searches for nontrivial infra-red fixed points in models beyond\nthe standard model.",
        "positive": "Developments in lattice QCD for matter at high temperature and density: A brief overview of the QCD phase diagram at nonzero temperature and density\nis provided. It is explained why standard lattice QCD techniques are not\nimmediately applicable for its determination, due to the sign problem. We then\ndiscuss a selection of recent lattice approaches that attempt to evade the sign\nproblem and classify them according to the underlying principle: constrained\nsimulations (density of states, histograms), holomorphicity (complex Langevin,\nLefschetz thimbles), partial summations (clusters, subsets, bags) and change in\nintegration order (strong coupling, dual formulations)."
    },
    {
        "anchor": "$DDK$ system in finite volume: The $DDK$ 3-body system is supposed to be bound due to the strongly\nattractive interaction between the $D$ meson and the $K$ meson in the isospin\nzero channel. The minimum quark content of this 3-body bound state is\n$cc\\bar{q}\\bar{s}$ with $q=u,d$. It will be an explicitly exotic tetraquark\nstate once discovered. In order to confirm the phenomenological study of the\n$DDK$ system, we can refer to lattice QCD as a powerful theoretical tool\nparallel to the experiment measurement. In this paper, a 3-body quantization\ncondition scheme is derived via the non-relativistic effective theory and the\nparticle-dimer picture in finite volume. Lattice spectrum of this 3-body system\nis calculated within the existing model inputs. The spectrum shows various\ninteresting properties of the $DDK$ system, and it may reveal the nature of the\n$D^*(2317)$. This predicated spectrum is expected to be tested in future\nlattice simulations.",
        "positive": "Lattice QCD constraints on the parton distribution functions of\n  ${}^3\\text{He}$: The fraction of the longitudinal momentum of ${}^3\\text{He}$ that is carried\nby the isovector combination of $u$ and $d$ quarks is determined using lattice\nQCD for the first time. The ratio of this combination to that in the\nconstituent nucleons is found to be consistent with unity at the few-percent\nlevel from calculations with quark masses corresponding to $m_\\pi\\sim 800$ MeV,\nextrapolated to the physical quark masses. This constraint is consistent with,\nand significantly more precise than, determinations from global nuclear parton\ndistribution function fits. Including the lattice QCD determination of the\nmomentum fraction in the nNNPDF global fitting framework results in the\nuncertainty on the isovector momentum fraction ratio being reduced by a factor\nof 2.5, and thereby enables a more precise extraction of the $u$ and $d$ parton\ndistributions in ${}^3\\text{He}$."
    },
    {
        "anchor": "Chiral phase transition temperature in (2+1)-Flavor QCD: We present a lattice QCD based determination of the chiral phase transition\ntemperature in QCD with two degenerate, massless quarks and a physical strange\nquark mass. We propose and calculate two novel estimators for the chiral\ntransition temperature for several values of the light quark masses,\ncorresponding to Goldstone pion masses in the range of $58~{\\rm MeV}\\lesssim\nm_\\pi\\lesssim 163~{\\rm MeV}$. The chiral phase transition temperature is\ndetermined by extrapolating to vanishing pion mass using universal scaling\nanalysis. Finite volume effects are controlled by extrapolating to the\nthermodynamic limit using spatial lattice extents in the range of $2.8$-$4.5$\ntimes the inverse of the pion mass. Continuum extrapolations are carried out by\nusing three different values of the lattice cut-off, corresponding to lattices\nwith temporal extent $N_\\tau=6,\\ 8$ and $12$. After thermodynamic, continuum\nand chiral extrapolations we find the chiral phase transition temperature\n$T_c^0=132^{+3}_{-6}$ MeV.",
        "positive": "Gluon Parton Distribution of the Pion and Nucleon from Lattice QCD: We present the $x$-dependent nucleon and pion gluon distribution from lattice\nQCD using the pseudo-PDF approach, on lattice ensembles with $2+1+1$ flavors of\nhighly improved staggered quarks (HISQ), generated by MILC Collaboration. We\nuse clover fermions for the valence action and momentum smearing to achieve\npion boost momentum up to 2.56~GeV on three lattice spacings $a\\approx 0.9,\n0.12$ and 0.15~fm and three pion masses $M_{\\pi}\\approx 220$, 310 and 690~MeV.\nWe compare our pion and preliminary nucleon gluon results with the\ndetermination by global fits."
    },
    {
        "anchor": "On the temperature dependence of the electrical conductivity in hot\n  quenched lattice QCD: Extending our recent work, we report on a calculation of the vector current\ncorrelation function for light valence quarks in the deconfined phase of\nquenched QCD in the temperature range 1.16Tc<T<2.98Tc. After performing a\nsystematic analysis of the in fluence of cut-off effects on light quark meson\ncorrelators using clover improved Wilson fermions, we discuss resulting\nconstraints on the electrical conductivity in a quark gluon plasma.",
        "positive": "Resonances in an external field: the 1+1 dimensional case: Using non-relativistic effective field theory in 1+1 dimensions, we\ngeneralize Luescher's approach for resonances in the presence of an external\nfield. This generalized approach provides a framework to study the\ninfinite-volume limit of the form factor of a resonance determined in lattice\nsimulations."
    },
    {
        "anchor": "Nucleon and pion structure with lattice QCD simulations at physical\n  value of the pion mass: We present results on the nucleon scalar, axial and tensor charges as well as\non the momentum fraction, and the helicity and transversity moments. The pion\nmomentum fraction is also presented. The computation of these key observables\nis carried out using lattice QCD simulations at a physical value of the pion\nmass. The evaluation is based on gauge configurations generated with two\ndegenerate sea quarks of twisted mass fermions with a clover term. We\ninvestigate excited states contributions with the nucleon quantum numbers by\nanalyzing three sink-source time separations. We find that, for the scalar\ncharge, excited states contribute significantly and to a less degree to the\nnucleon momentum fraction and helicity moment. Our analysis yields a value for\nthe nucleon axial charge agrees with the experimental value and we predict a\nvalue of 1.027(62) in the $\\overline{\\text{MS}}$ scheme at 2 GeV for the\nisovector nucleon tensor charge directly at the physical point. The pion\nmomentum fraction is found to be $\\langle\nx\\rangle_{u-d}^{\\pi^\\pm}=0.214(15)(^{+12}_{-9})$ in the $\\overline{\\rm MS}$ at\n2 GeV.",
        "positive": "Study of Chiral Symmetry and $U(1)_A$ using Spatial Correlators for\n  $N_f=2+1$ QCD at finite temperature with Domain Wall Fermions: Based on simulations of 2+1 flavor lattice QCD with M\\\"obius domain wall\nfermions at high temperatures, we compute a series of spatial correlation\nfunctions to study the screening masses in mesonic states. We compare these\nmasses with the symmetry relations for various quark masses and lattice sizes\nat temperatures above the critical point. Using these spatial correlation\nfunctions we examine the $SU(2)_L \\times SU(2)_R$ symmetry as well as the\nanomalously broken axial $U(1)_A$ symmetry. Additionally we explore a possible\nand emergent chiral-spin symmetry $SU(2)_{CS}$."
    },
    {
        "anchor": "Grid: OneCode and FourAPIs: We discuss a substantial update to the Grid software library for Lattice QCD,\nenabling it to port to multiple GPU architectures while retaining CPU\nvectorisation and SIMD execution within OpenMP threads. The GPU environments\nsupported include vendor specific Nvidia CUDA and AMD HIP environments and a\n(mostly) standards based SYCL implementation. This is performed by an internal\nabstraction interface giving single source cross-platform performance\nportability across all number of planned Exascale architectures, and all those\nplanned by the US Department of Energy.",
        "positive": "Applications of Lattice Gauge Equivariant Neural Networks: The introduction of relevant physical information into neural network\narchitectures has become a widely used and successful strategy for improving\ntheir performance. In lattice gauge theories, such information can be\nidentified with gauge symmetries, which are incorporated into the network\nlayers of our recently proposed Lattice Gauge Equivariant Convolutional Neural\nNetworks (L-CNNs). L-CNNs can generalize better to differently sized lattices\nthan traditional neural networks and are by construction equivariant under\nlattice gauge transformations. In these proceedings, we present our progress on\npossible applications of L-CNNs to Wilson flow or continuous normalizing flow.\nOur methods are based on neural ordinary differential equations which allow us\nto modify link configurations in a gauge equivariant manner. For simplicity, we\nfocus on simple toy models to test these ideas in practice."
    },
    {
        "anchor": "Core -- a New Method for Solving Hamiltonian Lattice Systems: The COntractor REnormalization group (CORE) approximation, a new method for\nsolving Hamiltonian lattice systems, is introduced. The approach combines\nvariational and contraction techniques with the real-space renormalization\ngroup approach and is systematically improvable. Since it applies to lattice\nsystems of infinite extent, the method is suitable for studying critical\nphenomena and phase structure; systems with dynamical fermions can also be\ntreated. The method is tested using the 1+1-dimensional Ising model.",
        "positive": "Application of heavy-quark effective theory to lattice QCD: II.\n  Radiative corrections to heavy-light currents: We apply heavy-quark effective theory to separate long- and short-distance\neffects of heavy quarks in lattice gauge theory. In this approach, the inverse\nheavy-quark mass and the lattice spacing are treated as short distances, and\ntheir effects are lumped into short-distance coefficients. We show how to use\nthis formalism to match lattice gauge theory to continuum QCD, order by order\nin the heavy-quark expansion. In this paper, we focus on heavy-light currents.\nIn particular, we obtain one-loop results for the matching factors of lattice\ncurrents, needed for heavy-quark phenomenology, such as the calculation of\nheavy-light decay constants, and heavy-to-light transition form factors.\nResults for the Brodsky-Lepage-Mackenzie scale $q^*$ are also given."
    },
    {
        "anchor": "Aharonov-Bohm effect, Center Monopoles and Center Vortices in SU(2)\n  Lattice Gluodynamics: SU(2) gluodynamics is investigated numerically and analytically in the\n(Indirect) Maximal Center gauge at finite temperature. The center vortices are\nshown to be condensed in the confinement phase and dilute in the deconfinement\nphase. A new physical object, center monopole, is constructed. We show that the\ncenter monopole condensate is the order parameter of deconfinement phase\ntransition. The linking of the vortex worldsheets and quark trajectories is\nidentified with the Aharonov-Bohm interaction in an effective Abelian Higgs\ntheory. We conclude that the confinement in the Maximal Center gauge can be\nexplained by a new mechanism called \"the real superconductor mechanism\".",
        "positive": "Lattice DIS Structure Functions: We present the computation, in lattice QCD, of the renormalization constants\nand mixing coefficients of operators that measure the first two moments of DIS\nStructure Functions. These calculations have been performed using the\nSheikholeslami-Wohlert O(a) improved ``clover'' action, which is known to\nreduce the systematic error associated with the finiteness of the lattice\nspacing a. Due to the complexities of the computations, we have developed,\nusing the computer languages Schoonschip and Form, general codes that are able\nto automatically carry out all the analytic lattice manipulations."
    },
    {
        "anchor": "QCD vacuum and confinement: This course consists of two lectures. In the first lecture I discuss why a\nnon perturbative formulation of QCD is needed, and I show that lattice\nformulation copes with this need, even if it mainly produces numerical results.\nIn the second lecture I discuss how lattice can help to understand the\ndeconfinement transition.Such understanding is also important to predict\nparameters that can help in the interpretation of heavy ions high energy\nexperiments.",
        "positive": "Topological fermion condensates from anomalies: We show that a class of fermion theory formulated on a compact, curved\nmanifold will generate a condensate whose magnitude is determined only by the\nvolume and Euler characteristic of the space. The construction requires that\nthe fermions be treated as K\\\"{a}hler-Dirac fields and the condensate arises\nfrom an anomaly associated with a $U(1)$ global symmetry which is subsequently\nbroken to a discrete subgroup. Remarkably the anomaly survives under\ndiscretization of the space which allows us to compute the condensate on an\narbitrary triangulation. The results, being topological in character, should\nhold in a wide range of gravitationally coupled fermion theories both classical\nand quantum"
    },
    {
        "anchor": "B -> D l nu form factors and the determination of |Vcb|: The zero recoil limit of the B -> D l nu form factors is calculated on the\nlattice, which provides a model-independent determination of |Vcb|. Considering\na ratio of form factors, in which the bulk of statistical and systematic errors\ncancel, we obtain a precise result both for h_+(1) and for h_-(1).",
        "positive": "A Numerical Study of the 2-Flavour Schwinger Model with Dynamical\n  Overlap Hypercube Fermions: We present numerical results for the 2-flavour Schwinger model with dynamical\nchiral lattice fermions. We insert an approximately chiral hypercube Dirac\noperator into the overlap formula to construct the overlap hypercube operator.\nThis is an exact solution to the Ginsparg-Wilson relation, with an excellent\nlevel of locality and scaling. Due to its similarity with the hypercubic\nkernel, a low polynomial in this kernel provides a numerically efficient Hybrid\nMonte Carlo force. We measure the microscopic Dirac spectrum and discuss the\ncorresponding scale-invariant parameter, which takes a surprising form. This is\nan interesting case, since Random Matrix Theory is unexplored for this setting,\nwhere the chiral condensate {\\Sigma} vanishes in the chiral limit. We also\nmeasure {\\Sigma} and the \"pion\" mass, in distinct topological sectors. In this\ncontext we discuss and probe the topological summation of observables by\nvarious methods, as well as the evaluation of the topological susceptibility.\nThe feasibility of this summation is essential for the prospects of dynamical\noverlap fermions in QCD."
    },
    {
        "anchor": "Scaling of FLIC Fermions: Hadron masses are calculated in quenched lattice QCD on a variety of lattices\nin order to probe the scaling behavior of the Fat-Link Irrelevant Clover (FLIC)\nfermion action, a fat-link clover fermion action in which the purely irrelevant\noperators of the fermion action are constructed using APE-smeared links. The\nscaling analysis indicates FLIC fermions provide a new form of nonperturbative\nO(a) improvement where near-continuum results are obtained at finite lattice\nspacing.",
        "positive": "Cutoff effects for Wilson twisted mass fermions at tree-level of\n  perturbation theory: We study cutoff effects at tree-level of perturbation theory for standard\nWilson and Wilson twisted mass fermionic lattice actions with Nf=2 flavour\ndegenerate quarks. The discretization effects are investigated by computing the\nmass spectrum and decay amplitudes for different hadron interpolating fields\nand the scaling behaviour towards the continuum limit is analyzed. It is shown\nthat the Wilson and the mass average methods are equivalent and lead to O(a)\nimproved R5-parity even lattice observables. We also demonstrate that automatic\nO(a) improvement works in case of Wilson twisted mass fermions at maximal twist\nand that this improvement is realized even if the condition of maximal twist is\nachieved only up to O(a) cutoff effects. We demonstrate that in the chiral\nlimit standard Wilson fermions show scaling violations of O(a^2) while for\nmaximally twisted mass fermions these violations are only of O(a^4). For our\nanalytical calculations, lattices with sizes L=aN and periodic boundary\nconditions in the spatial directions have been chosen while infinite extension\nin the time direction is considered."
    },
    {
        "anchor": "Examples of renormalization group transformations for image sets: Using the example of configurations generated with the worm algorithm for the\ntwo-dimensional Ising model, we propose renormalization group (RG)\ntransformations, inspired by the tensor RG, that can be applied to sets of\nimages. We relate criticality to the logarithmic divergence of the largest\nprincipal component. We discuss the changes in link occupation under the RG\ntransformation, suggest ways to obtain data collapse, and compare with the two\nstate tensor RG approximation near the fixed point.",
        "positive": "Light Hadron Spectrum in Quenched Lattice QCD with Staggered Quarks: Without chiral extrapolation, we achieved a realistic nucleon to (\\rho)-meson\nmass ratio of (m_N/m_\\rho = 1.23 \\pm 0.04 ({\\rm statistical}) \\pm 0.02 ({\\rm\nsystematic})) in our quenched lattice QCD numerical calculation with staggered\nquarks. The systematic error is mostly from finite-volume effect and the\nfinite-spacing effect is negligible. The flavor symmetry breaking in the pion\nand (\\rho) meson is no longer visible. The lattice cutoff is set at 3.63 (\\pm)\n0.06 GeV, the spatial lattice volume is (2.59 (\\pm) 0.05 fm)(^3), and bare\nquarks mass as low as 4.5 MeV are used. Possible quenched chiral effects in\nhadron mass are discussed."
    },
    {
        "anchor": "Dynamical overlap fermions: techniques and results: We summarize our recent investigations of lattice QCD with dynamical overlap\nfermions. We sketch algorithmic issues and our approach to solving them. We\nshow our measurement of the topological susceptibility. We describe a\ncomputation of the chiral condensate using an analysis of the distribution of\neigenmodes of the Dirac operator and Random Matrix Theory.",
        "positive": "M.C.R.G. Study of Fixed-connectivity Surfaces: We apply Monte Carlo Renormalization group to the crumpling transition in\nrandom surface models of fixed connectivity. This transition is notoriously\ndifficult to treat numerically. We employ here a Fourier accelerated Langevin\nalgorithm in conjunction with a novel blocking procedure in momentum space\nwhich has proven extremely successful in $\\lambda\\phi^4$. We perform two\nsuccessive renormalizations in lattices with up to $64^2$ sites. We obtain a\nresult for the critical exponent $\\nu$ in general agreement with previous\nestimates and similar error bars, but with much less computational effort. We\nalso measure with great accuracy $\\eta$. As a by-product we are able to\ndetermine the fractal dimension $d_H$ of random surfaces at the crumpling\ntransition."
    },
    {
        "anchor": "Simulating at Realistic Quark Masses: Light quark masses: We present new results for light quark masses. The calculations are performed\nusing two flavours of $O(a)$ improved Wilson fermions. We have reached lattice\nspacings as small as $a \\sim 0.07$fm and pion masses down to $m_{\\pi} \\sim\n340$MeV in our simulations. This gives us significantly better control on the\nchiral and continuum extrapolations.",
        "positive": "One Loop Renormalization of Fermilab Fermions: We discuss the current status of our automatic perturbation theory program as\napplied to Fermilab Fermions. We give an overview of our methods, a discussion\nof tree level matching, and one loop results for the coefficients of the higher\ndimension kinetic operators."
    },
    {
        "anchor": "Isovector Axial Form Factor of the Nucleon from Lattice QCD: The isovector axial form factor of the nucleon plays a key role in\ninterpreting data from long-baseline neutrino oscillation experiments. We\npresent a lattice QCD calculation of this form factor, introducing a new method\nto directly extract its z-expansion from lattice correlators. Our final\nparameterization of the form factor, which extends up to spacelike virtualities\nof 0.7 GeV^2 with fully quantified uncertainties, agrees with previous lattice\ncalculations but is significantly less steep than neutrino-deuterium scattering\ndata suggests.",
        "positive": "Off-diagonal correlators of conserved charges from lattice QCD and how\n  to relate them to experiment: Like fluctuations, non-diagonal correlators of conserved charges provide a\ntool for the study of chemical freeze-out in heavy ion collisions. They can be\ncalculated in thermal equilibrium using lattice simulations, and be connected\nto moments of event-by-event net-particle multiplicity distributions. We\ncalculate them from continuum extrapolated lattice simulations at $\\mu_B=0$,\nand present a finite-$\\mu_B$ extrapolation, comparing two different methods. In\norder to relate the grand canonical observables to the experimentally available\nnet-particle fluctuations and correlations, we perform a Hadron Resonance Gas\n(HRG) model analysis, which allows us to completely break down the\ncontributions from different hadrons. We then construct suitable hadronic\nproxies for fluctuations ratios, and study their behavior at finite chemical\npotentials. We also study the effect of introducing acceptance cuts, and argue\nthat the small dependence of certain ratios on the latter allows for a direct\ncomparison with lattice QCD results, provided that the same cuts are applied to\nall hadronic species. Finally, we perform a comparison for the constructed\nquantities for experimentally available measurements from the STAR\nCollaboration. Thus, we estimate the chemical freeze-out temperature to 165 MeV\nusing a strangeness-related proxy. This is a rather high temperature for the\nuse of the Hadron Resonance Gas, thus, further lattice studies are necessary to\nprovide first principle results at intermediate $\\mu_B$."
    },
    {
        "anchor": "A No-Go Theorem for the Compatibility between Involutions of the First\n  Order Differentials on a Lattice and the Continuum Limit: We prove that the following three properties can not match each other on a\nlattice, that differentials of coordinate functions are algebraically dependent\nto their involutive conjugates, that the involution on a lattice is an\nantihomomorphism and that differential calculus has a natural continuum limit.",
        "positive": "QCD on 2+2 anisotropic lattices: We discuss the implementation of QCD on 2+2 anisotropic lattices. Technical\ndetails regarding the choice of the action as well as perturbative and\nnon-perturbative improvement are analyzed. The physical applications of the\nprogram are presented."
    },
    {
        "anchor": "Numerical Study of the Ghost-Gluon Vertex in Landau gauge: We present a numerical study of the ghost-gluon vertex and of the\ncorresponding renormalization function \\widetilde{Z}_1(p^2) in minimal Landau\ngauge for SU(2) lattice gauge theory. Data were obtained for three different\nlattice volumes (V = 4^4, 8^4, 16^4) and for three lattice couplings \\beta =\n2.2, 2.3, 2.4. Gribov-copy effects have been analyzed using the so-called\nsmeared gauge fixing. We also consider two different sets of momenta (orbits)\nin order to check for possible effects due to the breaking of rotational\nsymmetry. The vertex has been evaluated at the asymmetric point (0;p,-p) in\nmomentum-subtraction scheme. We find that \\widetilde{Z}_1(p^2) is approximately\nconstant and equal to 1, at least for momenta p > ~ 1 GeV. This constitutes a\nnonperturbative verification of the so-called nonrenormalization of the Landau\nghost-gluon vertex. Finally, we use our data to evaluate the running coupling\nconstant \\alpha_s(p^2).",
        "positive": "Quark mass dependence of hadron masses from lattice QCD: We discuss lattice methods to obtain the derivatives of a lattice meson mass\nwith respect to the bare sea and valence quark masses. Applications are made to\nquenched and dynamical fermion configurations. We find evidence for significant\ndifferences between quenched and dynamical fermion configurations. We discuss\nhow to relate dependence on the bare lattice parameters to more\nphenomenologically useful quantities."
    },
    {
        "anchor": "Chiral condensate from the twisted mass Dirac operator spectrum: We present the results of our computation of the chiral condensate with\n$N_f=2$ and $N_f=2+1+1$ flavours of maximally twisted mass fermions. The\ncondensate is determined from the Dirac operator spectrum, applying the\nspectral projector method proposed by Giusti and Luscher. We use 3 lattice\nspacings and several quark masses at each lattice spacing to perform the chiral\nand continuum extrapolations. We study the effect of the dynamical strange and\ncharm quarks by comparing our results for $N_f=2$ and $N_f=2+1+1$ dynamical\nflavours.",
        "positive": "The scalar and tensor glueballs in the valence approximation: We evaluate the infinite volume, continuum limit of $0^{++}$ and $2^{++}$\nglueball masses in the valence approximation. We find $m_{0^{++}} = 1740 \\pm 71\n$~MeV and $m_{2^{++}} = 2359 \\pm 128 $~MeV, consistent with the interpretation\nof $f_0 ( 1710 )$ as the lightest scalar glueball."
    },
    {
        "anchor": "The Higgs phase as a spin glass phase in D=5 dimensional SU(2) gauge\n  Higgs theory: According to recent work of Greensite and Matsuyama, the Higgs phase of a\ngauge Higgs theory is distinguished from the confinement and massless phases by\nthe spontaneous breaking of a global center subgroup of the gauge group, and by\nconfinement type. This is contrary to the notion that there is no essential\ndistinction between the Higgs and confinement phases when the Higgs field is in\nthe fundamental representation of the gauge group. Although this new symmetry\nbreaking order parameter has been investigated in $D=4$ dimensions, there is so\nfar no check in a non-abelian gauge theory containing a massless as well as\nconfinement/Higgs phases, where the prediction is that the symmetry breaking\norder parameter will show transition lines separating the massless to Higgs and\nconfinement to Higgs phases, but not the massless to confinement phase. In this\nwork we map out the phase structure of the $D=5$ dimensional model, according\nto both the symmetry breaking parameter and thermodynamic observables, and\ncheck the assertion regarding the massless to confinement phase.",
        "positive": "Lattice QCD Applications on QPACE: QPACE is a novel massively parallel architecture optimized for lattice QCD\nsimulations. A single QPACE node is based on the IBM PowerXCell 8i processor.\nThe nodes are interconnected by a custom 3-dimensional torus network\nimplemented on an FPGA. The compute power of the processor is provided by 8\nSynergistic Processing Units. Making efficient use of these accelerator cores\nin scientific applications is challenging. In this paper we describe our\nstrategies for porting applications to the QPACE architecture and report on\nperformance numbers."
    },
    {
        "anchor": "Phases of three dimensional large N QCD on a continuum torus: It is established by numerical means that continuum large N QCD defined on a\nthree dimensional torus can exist in four different phases. They are (i)\nconfined phase; (ii) deconfined phase; (iii) small box at zero temperature and\n(iv) small box at high temperatures.",
        "positive": "Nucleon Structure and Hyperon Form factor from Lattice QCD: In this work, I report the latest lattice QCD calculations of nucleon and\nhyperon structure from chiral fermions in 2+1-flavor dynamical simulations. All\ncalculations are done with a chirally symmetric fermion action, domain-wall\nfermions, for valence quarks. % I begin with the latest lattice results on the\nnucleon structure, focusing on results from RBC/UKQCD using 2+1-flavor chiral\nfermion actions. We find the chiral-extrapolated axial coupling constant at\nphysical pion mass point to be 1.23(5), consistent with experimental value. The\nrenormalization constants for the structure functions are obtained from\nRI/MOM-scheme non-perturbative renormalization. We find first moments of the\npolarized and unpolarized nucleon structure functions at zero transfer momentum\nto be 0.133(13) and 0.203(23) respectively, using continuum chiral\nextrapolation. These are consistent with the experimental values, unlike\nprevious calculations which have been 50% larger. We also have a prediction for\nthe transversity, which we find to be 0.56(4). The twist-3 matrix element is\nconsistent with zero which agrees with the prediction of the Wandzura-Wilczek\nrelation.\n  In the second half of this work, I report an indirect dynamical estimation of\nthe strangeness proton magnetic moments using mixed actions. With the analysis\nof hyperon form factors and using charge symmetry, the strangeness of proton is\nfound to be $-0.066(26)$, consistent with the Adelaide-JLab Collaboration's\nresult. The hyperon $\\Sigma$ and $\\Xi$ axial coupling constants are also\nperformed for the first time in a lattice calculation, $g_{\\Sigma\\Sigma}=\n0.441(14)$ and $g_{\\Xi\\Xi} = -0.277(11)$."
    },
    {
        "anchor": "Lattice study of semileptonic form factors with twisted boundary\n  conditions: We apply twisted boundary conditions to lattice QCD simulations of\nthree-point correlation functions in order to access spatial components of\nhadronic momenta different from the integer multiples of 2 pi / L. We calculate\nthe vector and scalar form factors relevant to the K -> pi semileptonic decay\nand consider all the possible ways of twisting one of the quark lines in the\nthree-point functions. We show that the momentum shift produced by the twisted\nboundary conditions does not introduce any additional noise and easily allows\nto determine within a few percent statistical accuracy the form factors at\nquite small values of the four-momentum transfer, which are not accessible when\nperiodic boundary conditions are considered. The use of twisted boundary\nconditions turns out to be crucial for a precise determination of the form\nfactor at zero-momentum transfer, when a precise lattice point sufficiently\nclose to zero-momentum transfer is not accessible with periodic boundary\nconditions.",
        "positive": "Cutoff effects of heavy quark vacuum polarization at one-loop order: The charm-quark mass is typically not so far from the cutoff 1/a in lattice\nsimulations. Its determinant may then potentially introduce large cutoff\neffects. We choose the O(a)-improved Wilson formulation and compute the vacuum\npolarization effects in two rather different observables at one-loop order. One\nis the quark-antiquark static force and the other the Schroedinger functional\ncoupling; in addition we investigate two more quantities resulting from the\nlatter. In all the cases the lattice artifacts due to the charm-quark are small\nwhen compared to the gluonic effects. This indicates that the inclusion of\ncharm-quarks in dynamical fermion simulations is typically not a problem."
    },
    {
        "anchor": "Screening Masses of Hot SU(2) Gauge Theory from the 3d Adjoint Higgs\n  Model: We study the Landau gauge propagators of the lattice SU(2) 3d adjoint Higgs\nmodel, considered as an effective theory of high temperature 4d SU(2) gauge\ntheory. From the long distance behaviour of the propagators we extract the\nscreening masses. The propagators are studied both in the symmetric and the\nbroken phases of the 3d Higgs model. It is shown that the pole masses extracted\nfrom the propagators in the symmetric phase agree well with the screening\nmasses obtained recently in finite temperature SU(2) theory, while propagators\nmeasured in the broken phase show quite a different behaviour. This suggest\nthat the symmetric phase of the 3d model corresponds to the deconfined phase of\nthe 4d SU(2) gauge theory. The relation of the propagator masses to the masses\nextracted from gauge invariant correlators and the mass gap of pure 3d SU(2)\ngauge theory is also discussed.",
        "positive": "Dynamics of the Conformal Mode and Simplicial Gravity: We review the derivation of the Liouville action in 2DQG via the trace\nanomaly and emphasize how a similar approach can be used to derive an effective\naction describing the long wavelength dynamics of the conformal factor in 4D.\nIn 2D we describe how to make an explicit connection between dynamical\ntriangulations and this continuum theory, and present results which confirm the\nequivalance of the two approaches. By reconstructing a lattice conformal mode\nfrom DT simulations it should be possible to test this equivalence in 4D also."
    },
    {
        "anchor": "Chiral Fermions on the Lattice through Gauge Fixing -- Perturbation\n  Theory: We study the gauge-fixing approach to the construction of lattice chiral\ngauge theories in one-loop weak-coupling perturbation theory. We show how\ninfrared properties of the gauge degrees of freedom determine the nature of the\ncontinuous phase transition at which we take the continuum limit. The fermion\nself-energy and the vacuum polarization are calculated, and confirm that, in\nthe abelian case, this approach can be used to put chiral gauge theories on the\nlattice in four dimensions. We comment on the generalization to the nonabelian\ncase.",
        "positive": "Renormalization of Massive Lattice Fermions: The renormalization of a general action for massive lattice fermions is\ndiscussed. The analysis applies for all $m_q a$. Preliminary results for the\nself energy at one loop in perturbation theory are presented."
    },
    {
        "anchor": "Finite Volume Effects in Self Coupled Geometries: By integrating the pressure equation at the surface of a self coupled\ncurvilinear boundary, one may obtain asymptotic estimates of energy shifts,\nwhich is especially useful in lattice QCD studies of nonrelativistic bound\nstates. Energy shift expressions are found for periodic (antiperiodic) boundary\nconditions on antipodal points, which require Neumann (Dirichlet) boundary\nconditions for even parity states and Dirichlet (Neumann) boundary conditions\nfor odd parity states. It is found that averaging over periodic and\nantiperiodic boundary conditions is an effective way of removing the asymptotic\nenergy shifts from the boundary. Asymptotic energy shifts from boxes with self\ncoupled walls are also considered and shown to be effectively antipodal. The\nenergy shift equations are illustrated by the solution of the bounded harmonic\noscillator and hydrogen atoms.",
        "positive": "$D$ to $K$ semileptonic decay form factors from HISQ light and charm\n  quarks: We present a study of $D \\rightarrow K, l \\nu$ semileptonic decays on the\nlattice which employs the HISQ action for both the charm and the light quarks.\nWe work with MILC unquenched $N_f = 2 + 1$ lattices and determine the scalar\nform factor $f_0(q^2)$. This form factor is obtained from a scalar current\nmatrix element that does not require any operator matching. We find $f^{D\n\\rightarrow K}_0(0) \\equiv f^{D \\rightarrow K}_+(0) = 0.747(19)$ in the chiral\nplus continuum limit and hereby improve the theory error on this quantity by a\nfactor of $\\sim$4 compared to previous lattice determinations. Combining the\nnew theory result with recent experimental measurements of the product $f^{D\n\\rightarrow K}_+(0) * |V_{cs}| $ from BaBar and CLEO-c leads to a very precise\ndirect determination of the CKM matrix element $|V_{cs}| $, $|V_{cs}| =\n0.961(11)(24)$, where the first error comes from experiment and the second is\nthe lattice QCD theory error."
    },
    {
        "anchor": "Fermion mass in the Wilson-Yukawa approach for chiral Yukawa theory: We consider a modification of the Wilson-Yukawa model to overcome its\ndifficulty that the fermion mass is not proportional to the Higgs vacuum\nexpectation value. In the modification scalar and fermionic regulator fields\nare introduced so that all the physical fermion fields possess shift symmetry\nwhen the Yukawa coupling vanishes. With the fermionic hopping parameter\nexpansion it is shown that the fermion mass is proportional to the Higgs vacuum\nexpectation value and that the coupling of fermion to the external gauge field\ncan be chiral if the hopping parameter of the scalar regulator field is taken\nto the critical value.",
        "positive": "Lattice study on $\u03c0K $ scattering with moving wall source: The s-wave pion-kaon ($\\pi K$) scattering lengths at zero momentum are\ncalculated in lattice QCD with sufficiently light $u/d$ quarks and strange\nquark at its physical value by the finite size formula. The light quark masses\ncorrespond to $m_\\pi = 0.330 - 0.466$ GeV. In the \"Asqtad\" improved staggered\nfermion formulation, we measure the $\\pi K$ four-point correlators for both\nisospin $I=1/2$ and 3/2 channels, and analyze the lattice simulation data at\nthe next-to-leading order in the continuum three-flavor chiral perturbation\ntheory, which enables us a simultaneous extrapolation of $\\pi K$ scattering\nlengths at physical point. We adopt a technique with the moving wall sources\nwithout gauge fixing to obtain the substantiable accuracy, moreover, for $I =\n1/2$ channel, we employ the variational method to isolate the contamination\nfrom the excited states. Extrapolating to the physical point yields the\nscattering lengths as $m_\\pi a_{3/2} = -0.0505(19)$ and $m_\\pi a_{1/2} =\n0.1827(37)$ for $I=3/2$ and 1/2 channels, respectively. Our simulation results\nfor $\\pi K$ scattering lengths are in agreement with the experimental reports\nand theoretical predictions, and can be comparable with other lattice\nsimulations. These simulations are carried out with MILC $N_f = 2+1$ flavor\ngauge configurations at lattice spacing $a \\approx 0.15$ fm."
    },
    {
        "anchor": "Localization at the quenched SU(3) phase transition: It is known that the deconfining transition of QCD is accompanied by the\nappearance of localized eigenmodes at the low end of the Dirac spectrum. In the\nquenched case localization appears exactly at the critical temperature of\ndeconfinement. In the present work, using quenched simulations exactly at the\ncritical temperature, we show that the localization properties of low Dirac\nmodes change abruptly between the confined and deconfined phase. This means\nthat in the real Polyakov loop sector, the mobility edge has a discontinuity at\nthe critical temperature. In contrast, in the complex sector, there is no such\ndiscontinuity at $T_c$, even the lowest Dirac modes remain delocalized at the\ncritical temperature in the deconfined phase.",
        "positive": "Computation of the b-quark Mass with Perturbative Matching at the\n  Next-to-Next-to-Leading Order: We compute the two-loop term in the perturbation series for the quark-mass in\nthe lattice Heavy Quark Effective Theory. This is an ingredient in the matching\nfactor required to obtain the $b$-quark mass from lattice simulations of the\nHQET. Combining our calculations with numerical results from the APE\ncollaboration, we find, at two-loop order, $\\bar m_b \\equiv\nm_b^{\\bar{MS}}(m_b^{\\bar{MS}}) =4.41\\pm 0.05\\pm 0.10 $GeV. It was expected that\nthe two-loop term would have a significant effect and this is indeed what we\nfind. Depending on the choice of \"reasonable\" coupling constant in the one-loop\nestimates the result for $\\bar m_b$ can change by several hundred MeV when the\ntwo-loop terms are included."
    },
    {
        "anchor": "Octet baryon isovector charges from $N_f = 2 + 1$ lattice QCD: We determine the axial, scalar and tensor isovector charges of the nucleon,\nsigma and cascade baryons as well as the difference between the up and down\nquark masses, $m_u-m_d$. We employ gauge ensembles with $N_f=2+1$\nnon-perturbatively improved Wilson fermions at six values of the lattice\nspacing in the range $a\\approx (0.039 - 0.098) \\,$fm, generated by the\nCoordinated Lattice Simulations (CLS) effort. The pion mass $M_\\pi$ ranges from\naround $430 \\, $MeV down to a near physical value of $130 \\, $MeV and the\nlinear spatial lattice extent $L$ varies from $6.5\\,M_{\\pi}^{-1}$ to\n$3.0\\,M_{\\pi}^{-1}$, where $L M_\\pi \\geq 4$ for the majority of the ensembles.\nThis allows us to perform a controlled interpolation/extrapolation of the\ncharges to the physical mass point in the infinite volume and continuum limit.\nInvestigating SU(3) flavour symmetry, we find moderate symmetry breaking\neffects for the axial charges at the physical quark mass point, while no\nsignificant effects are found for the other charges within current\nuncertainties.",
        "positive": "Multigrid Algorithms for Domain-Wall Fermions: We describe an adaptive multigrid algorithm for solving inverses of the\ndomain-wall fermion operator. Our multigrid algorithm uses an adaptive\nprojection of near-null vectors of the domain-wall operator onto coarser\nfour-dimensional lattices. This extension of multigrid techniques to a chiral\nfermion action will greatly reduce overall computation cost, and the\nelimination of the fifth dimension in the coarse space reduces the relative\ncost of using chiral fermions compared to discarding this symmetry. We\ndemonstrate near-elimination of critical slowing as the quark mass is reduced\nand small volume dependence, which may be suppressed by taking advantage of the\nrecursive nature of the algorithm."
    },
    {
        "anchor": "Heavy light tetraquarks from Lattice QCD: We present preliminary results from a lattice calculation of tetraquark\nstates in the charm and bottom sector of the type $ud\\bar{b}\\bar{b}$,\n$us\\bar{b}\\bar{b}$, $ud\\bar{c}\\bar{c}$ and $sc\\bar{b}\\bar{b}$. These\ncalculations are performed on $N_f = 2 + 1 + 1$ MILC ensembles with lattice\nspacing of $a = 0.12~\\mathrm{fm} $ and $a=0.06~\\mathrm{fm} $. A relativistic\naction with overlap fermions is employed for the light and charm quarks while a\nnon-relativistic action with non-perturbatively improved coefficients is used\nin the bottom sector. Preliminary results provide a clear indication of\npresence of energy levels below the relevant thresholds of different tetraquark\nstates. While in double charm sector we find shallow bound levels, our results\nsuggest deeply bound levels with double bottom tetraquarks.",
        "positive": "Constraints on the IR behavior of the ghost propagator in Yang-Mills\n  theories: We present rigorous upper and lower bounds for the momentum-space ghost\npropagator G(p) of Yang-Mills theories in terms of the smallest nonzero\neigenvalue (and of the corresponding eigenvector) of the Faddeev-Popov matrix.\nWe apply our analysis to data from simulations of SU(2) lattice gauge theory in\nLandau gauge, using the largest lattice sizes to date. Our results suggest\nthat, in three and in four space-time dimensions, the Landau-gauge ghost\npropagator is not enhanced as compared to its tree-level behavior. This is also\nseen in plots and fits of the ghost dressing function. In the two dimensional\ncase, on the other hand, we find that G(p) diverges as p^{-2-2 kappa} with\nkappa \\approx 0.15, in agreement with Ref. [1]. We note that our discussion is\ngeneral, although we make an application only to pure gauge theory in Landau\ngauge. Most of our simulations have been performed on the IBM supercomputer at\nthe University of Sao Paulo."
    },
    {
        "anchor": "The non-perturbative QCD Debye mass from a Wilson line operator: According to a proposal by Arnold and Yaffe, the non-perturbative\ng^2T-contribution to the Debye mass in the deconfined QCD plasma phase can be\ndetermined from a single Wilson line operator in the three-dimensional pure\nSU(3) gauge theory. We extend a previous SU(2) measurement of this quantity to\nthe physical SU(3) case. We find a numerical coefficient which is more accurate\nand smaller than that obtained previously with another method, but still very\nlarge compared with the naive expectation: the correction is larger than the\nleading term up to T ~ 10^7 T_c, corresponding to g^2 ~ 0.4. At moderate\ntemperatures T ~ 2 T_c, a consistent picture emerges where the Debye mass is\nm_D ~ 6T, the lightest gauge invariant screening mass in the system is ~ 3T,\nand the purely magnetic operators couple dominantly to a scale ~ 6T. Electric\n(~ gT) and magnetic (~ g^2T) scales are therefore strongly overlapping close to\nthe phase transition, and the colour-electric fields play an essential role in\nthe dynamics.",
        "positive": "An ideal toy model for confining, walking and conformal gauge theories:\n  the O(3) sigma model with theta-term: A toy model is proposed for four dimensional non-abelian gauge theories\ncoupled to a large number of fermionic degrees of freedom. As the number of\nflavors is varied the gauge theory may be confining, walking or conformal. The\ntoy model mimicking this feature is the two dimensional O(3) sigma model with a\ntheta-term. For all theta the model is asymptotically free. For small theta the\nmodel is confining in the infra red, for theta = pi the model has a non-trivial\ninfra red fixed point and consequently for theta slightly below pi the coupling\nwalks. The first step in investigating the notoriously difficult systematic\neffects of the gauge theory in the toy model is to establish non-perturbatively\nthat the theta parameter is actually a relevant coupling. This is done by\nshowing that there exist quantities that are entirely given by the total\ntopological charge and are well defined in the continuum limit and are\nnon-zero, despite the fact that the topological susceptibility is divergent.\nMore precisely it is established that the differences of connected correlation\nfunctions of the topological charge (the cumulants) are finite and non-zero and\nconsequently there is only a single divergent parameter in Z(theta) but\notherwise it is finite. This divergent constant can be removed by an\nappropriate counter term rendering the theory completely finite even at theta >\n0."
    },
    {
        "anchor": "Fractal Dimension of Gauge-fixing Defects: The fractal dimension $D_f$ of sites resisting Landau or maximal Abelian(MA)\ngauge fixing in lattice $SU(3)$ gluodynamics is defined and computed. In Landau\ngauge such sites clump into $D_f\\sim 1$ clusters in the confining phase. In the\nfinite temperature phase their dimensionality drops to $D_f < 1$, that is,\nclustering seems to dissipate. In contrast, MA gauge resistant sites fail to\nexhibit a notable tendency to cluster at any temperature.",
        "positive": "The Schr\u00f6dinger functional in lattice QCD with exact chiral symmetry: Similarly to the interaction lagrangian, the possible boundary conditions in\nquantum field theories on space-time manifolds with boundaries are strongly\nconstrained by the symmetry and scaling properties of the theory. Based on this\ngeneral insight, a lattice formulation of the QCD Schr\\\"odinger functional is\nproposed for the case where the lattice Dirac operator in the bulk of the\nlattice coincides with the Neuberger--Dirac operator. The construction\nsatisfies all basic requirements (locality, symmetries, hermiticity) and is\nsuitable for numerical simulations."
    },
    {
        "anchor": "Emergent phenomena from centre vortices: Quark confinement is perhaps the most important emergent property of the\ntheory of quantum chromodynamics. Herein we review some key aspects of centre\nvortices in SU(3) lattice gauge theory. Starting from the original Monte Carlo\ngauge fields, a vortex identification procedure yields vortex-removed and\nvortex-only backgrounds. The comparison between the original `untouched' Monte\nCarlo gauge fields and these so called vortex-modified ensembles has provided a\nvariety of results that support the notion that centre vortices are fundamental\nto confinement in pure gauge theory. For the first time we perform direct\nnumerical tests of the response of centre vortices to the presence of dynamical\nquarks in SU(3).",
        "positive": "On Scale Determination in Lattice QCD with Dynamical Quarks: Dependence of a/r_c (inverse Sommer parameter in units of lattice spacing a)\non am_q (quark mass in lattice unit) has been observed in all lattice QCD\nsimulations with sea quarks including the ones with improved actions. How much\nof this dependence is a scaling violation has remained an intriguing question.\nOur approach has been to investigate the issue with an action with known\nlattice artifacts, i.e., the standard Wilson quark and gauge action with\nbeta=5.6 and 2 degenerate flavors of sea quarks on 16^3 times 32 lattices. In\norder to study in detail the sea quark mass dependence, measurements are\ncarried out at eight values of the PCAC quark mass values am_q from about 0.07\nto below 0.015. Though scaling violations may indeed be present for relatively\nlarge am_q, a consistent scenario at sufficiently small am_q seems to emerge in\nthe mass-independent scheme where for a fixed beta, 1/r_0 and sqrt{sigma} have\nlinear dependence on m_q as physical effects similar to the quark mass\ndependence of the rho mass. We present evidence for this scenario and\naccordingly extract the lattice scale (a = 0.0805(7) fm, a^{-1} = 2.45(2) GeV)\nby chiral extrapolation to the physical point."
    },
    {
        "anchor": "Lattice QCD with Domain Decomposition on Intel Xeon Phi Co-Processors: The gap between the cost of moving data and the cost of computing continues\nto grow, making it ever harder to design iterative solvers on extreme-scale\narchitectures. This problem can be alleviated by alternative algorithms that\nreduce the amount of data movement. We investigate this in the context of\nLattice Quantum Chromodynamics and implement such an alternative solver\nalgorithm, based on domain decomposition, on Intel Xeon Phi co-processor (KNC)\nclusters. We demonstrate close-to-linear on-chip scaling to all 60 cores of the\nKNC. With a mix of single- and half-precision the domain-decomposition method\nsustains 400-500 Gflop/s per chip. Compared to an optimized KNC implementation\nof a standard solver [1], our full multi-node domain-decomposition solver\nstrong-scales to more nodes and reduces the time-to-solution by a factor of 5.",
        "positive": "Background field Landau mode operators for the nucleon: The introduction of a uniform background magnetic field breaks\nthree-dimensional spatial symmetry for a charged particle and introduces Landau\nmode effects. Standard quark operators are inefficient at isolating the nucleon\ncorrelation function at nontrivial field strengths. We introduce novel quark\noperators constructed from the two-dimensional Laplacian eigenmodes that\ndescribe a charged particle on a finite lattice. These eigenmode-projected\nquark operators provide enhanced precision for calculating nucleon energy\nshifts in a magnetic field. Preliminary results are obtained for the neutron\nand proton magnetic polarisabilities using these methods."
    },
    {
        "anchor": "Quark Chromoelectric Dipole Moment Contribution to the Neutron Electric\n  Dipole Moment: The quark chromo-electric dipole moment operator and the pseudo-scalar\nfermion bilinear with which it mixes under renormalization can both be included\nin a calculation of the electromagnetic form factor of the nucleon using the\nSchwinger source method. A preliminary calculation of these operators using\nclover quarks on HISQ lattices generated by MILC collaboration will be\npresented showing the quality of the signal in the correlators necessary for\ncalculating the neutron electric dipole moment.",
        "positive": "The Confinement Problem in Lattice Gauge Theory: I review investigations of the quark confinement mechanism that have been\ncarried out in the framework of SU(N) lattice gauge theory. The special role of\nZ(N) center symmetry is emphasized."
    },
    {
        "anchor": "Combining ordinary and topological finite volume effects for fixed\n  topology simulations: In lattice quantum field theories with topological sectors, simulations at\nfine lattice spacings --- with typical algorithms --- tend to freeze\ntopologically. In such cases, specific topological finite size effects have to\nbe taken into account to obtain physical results, which correspond to infinite\nvolume or unfixed topology. Moreover, when a theory like QCD is simulated in a\nmoderate volume, one also has to overcome ordinary finite volume effects (not\nrelated to topology freezing). To extract physical results from simulations\naffected by both types of finite volume effects, we extend a known relation\nbetween hadron masses at fixed and unfixed topology by additionally\nincorporating ordinary finite volume effects. We present numerical results for\nSU(2) Yang-Mills theory.",
        "positive": "Critical behavior of the correlation function of three-dimensional O(N)\n  models in the symmetric phase: We present new strong-coupling series for O(N) spin models in three\ndimensions, on the cubic and diamond lattices. We analyze these series to\ninvestigate the two-point Green's function G(x) in the critical region of the\nsymmetric phase. This analysis shows that the low-momentum behavior of G(x) is\nessentially Gaussian for all N from zero to infinity. This result is also\nsupported by a large-N analysis."
    },
    {
        "anchor": "An investigation into a wavelet accelerated gauge fixing algorithm: We introduce an acceleration algorithm for coulomb gauge fixing, using the\ncompactly supported wavelets introduced by Daubechies. The algorithm is similar\nto Fourier acceleration. Our provisional numerical results for $SU(3)$ on\n$8^{4}$ lattices show that the acceleration based on the DAUB6 transform can\nreduce the number of iterations by a factor up to 3 over the unaccelerated\nalgorithm. The reduction in iterations for Fourier acceleration is\napproximately a factor of 7.",
        "positive": "Center Vortices at N > 4 Colors: We discuss two issues related to the physics of center vortices in pure SU(N)\nlattice gauge theory at large N: (1) Center vortices are stable classical\nsolutions of the Wilson action, as well as of a wide class of improved lattice\nactions, for any N > 4. (2) The natural scaling of k-string tensions at large\nN, in the vortex picture of confinement, is \\sigma(k)=k \\sigma(1). This is the\ncommon large N limit of Casimir and Sine Law scaling. The crucial feature for\nexplaining this behavior is the existence of center monopoles."
    },
    {
        "anchor": "Four-quark energies in SU(2) lattice Monte Carlo using a tetrahedral\n  geometry: This contribution -- a continuation of earlier work -- reports on recent\ndevelopments in the calculation and understanding of 4-quark energies generated\nusing lattice Monte Carlo techniques.",
        "positive": "A definition of the running coupling constant in a twisted SU(2) lattice\n  gauge theory: We propose a definition of the running coupling constant in a SU(2) lattice\ngauge theory with twisted boundary conditions. It is based on the correlation\nof Polyakov loops extended in a twisted direction at a distance which is a\nfixed fraction of the totale lattice size. We make the perturbative calculation\nwhich connects this definition to standard regularization schemes. We find\nLambda_Twisted-Polyakov/Lambda_MSbar = 1.6136(2)."
    },
    {
        "anchor": "On the energy momentum dispersion in the lattice regularization: For a free scalar boson field and for U(1) gauge theory finite volume\n(infrared) and other corrections to the energy-momentum dispersion in the\nlattice regularization are investigated calculating energy eigenstates from the\nfall off behavior of two-point correlation functions. For small lattices the\nsquared dispersion energy defined by $E_{\\rm\ndis}^2=E_{\\vec{k}}^2-E_0^2-4\\sum_{i=1}^{d-1}\\sin(k_i/2)^2$ is in both cases\nnegative ($d$ is the Euclidean space-time dimension and $E_{\\vec{k}}$ the\nenergy of momentum $\\vec{k}$ eigenstates). Observation of $E_{\\rm dis}^2=0$ has\nbeen an accepted method to demonstrate the existence of a massless photon\n($E_0=0$) in 4D lattice gauge theory, which we supplement here by a study of\nits finite size corrections. A surprise from the lattice regularization of the\nfree field is that infrared corrections do {\\it not} eliminate a difference\nbetween the groundstate energy $E_0$ and the mass parameter $M$ of the free\nscalar lattice action. Instead, the relation $E_0=\\cosh^{-1} (1+M^2/2)$ is\nderived independently of the spatial lattice size.",
        "positive": "Numerical simulation of random paths with a curvature dependent action: We study an ensemble of closed random paths, embedded in R^3, with a\ncurvature dependent action. Previous analytical results indicate that there is\nno crumpling transition for any finite value of the curvature coupling.\nNevertheless, in a high statistics numerical simulation, we observe two\ndifferent regimes for the specific heat separated by a rather smooth structure.\nThe analysis of this fact warns us about the difficulties in the interpretation\nof numerical results obtained in cases where theoretical results are absent and\na high statistics simulation is unreachable. This may be the case of random\nsurfaces."
    },
    {
        "anchor": "The hadronic vacuum polarization contribution to $(g_\u03bc-2)$: Lattice\n  QCD+QED calculations: The anomalous magnetic moment of the muon $a_\\mu$ is one of the most accurate\nquantities in Particle Physics. The long-standing discrepancy of about $3.7$\nstandard deviations between the experimental value and the prediction of the\nStandard Model could represent an intriguing indication of New Physics. The\nexperiments at Fermilab (E989) and at J-PARC (E34) aim at reducing\nsignificantly the experimental uncertainty, thus making the theoretical one due\nto hadronic corrections the main limitation of this stringent test of the\nStandard Model. In this contribution we present the results of a\nfirst-principles lattice calculation of the hadronic vacuum polarization (HVP)\ncontribution to $a_\\mu$, including electromagnetic and $SU(2)$-breaking\ncorrections. Our determination, $a_\\mu^{\\rm HVP} = 682.0 ~ (18.7) \\cdot\n10^{-10}$, turns out to be in agreement with recent theoretical determinations\nbased on the dispersive analyses of the experimental cross section data for the\nannihilation process $e^+e^- \\to hadrons$. Furthermore, we provide for the\nfirst time a lattice estimate for the missing part of $a_\\mu^{\\rm HVP}$ not\ncovered in the MUonE experiment, $\\left[a_\\mu^{\\rm HVP}\\right]_> = 91.6 ~ (2.0)\n\\cdot 10^{-10}$.",
        "positive": "Taylor expansions on Lefschetz thimbles (and not only that): Thimble regularisation is a possible solution to the sign problem, which is\nevaded by formulating quantum field theories on manifolds where the imaginary\npart of the action stays constant (Lefschetz thimbles). A major obstacle is due\nto the fact that one in general needs to collect contributions coming from more\nthan one thimble. Here we explore the idea of performing Taylor expansions on\nLefschetz thimbles. We show that in some cases we can compute expansions in\nregions where only the dominant thimble contributes to the result in such a way\nthat these (different, disjoint) regions can be bridged. This can most\neffectively be done via Pad\\'e approximants. In this way multi-thimble\nsimulations can be circumvented. The approach can be trusted provided we can\nshow that the analytic continuation we are performing is a legitimate one,\nwhich thing we can indeed show. We briefly discuss two prototypal computations,\nfor which we obtained a very good control on the analytical structure (and\nsingularities) of the results. All in all, the main strategy that we adopt is\nsupposed to be valuable not only in the thimble approach, which thing we\nfinally discuss."
    },
    {
        "anchor": "Extrapolating semileptonic form factors using Bayesian-inference fits\n  regulated by unitarity and analyticity: We discuss our recently proposed model-independent framework for fitting\nhadronic form-factor data, which are often only available at discrete\nkinematical points, using parameterisations based on unitarity and analyticity.\nThe accompanying dispersive bound on the form factors (unitarity constraint) is\nused to regulate the ill-posed fitting problem and allow model-independent\npredictions over the entire physical range. Kinematical constraints, for\nexample for the vector and scalar form factors in semileptonic meson decays,\ncan be imposed exactly. The core formulae are straight-forward to implement\nwith standard math libraries. We demonstrate the method for the exclusive\nsemileptonic decay $B_s\\to K\\ell\\nu$, an example requiring one to use a\ngeneralisation of the original Boyd Grinstein Lebed (BGL) unitarity constraint.\nWe further present a first application of the method to $B \\to D^*\\ell \\nu$\ndecays.",
        "positive": "Strange nucleon form factors and isoscalar charges with $N_f=2+1$\n  $\\mathcal{O}(a)$-improved Wilson fermions: We report on our calculation of the strange contribution to the vector and\naxial vector form factors. The strange charge radii, magnetic moment, and axial\ncharge are extracted by model independent $z$-expansion fits to the\n$Q^2$-dependence of the respective form factors. Furthermore, the isoscalar\ncontribution to the axial and tensor charge is investigated by combining the\ncalculation of connected and disconnected diagrams. The required\nrenormalization is performed with the Rome-Southampton method. We make use of\nthe CLS $N_f=2+1$ $\\mathcal{O}(a)$-improved Wilson fermion ensembles. Results\nare reported for pion masses in the range $m_\\pi=200-360\\,\\text{MeV}$ and\nlattice spacings $a=0.05-0.086\\,\\text{fm}$."
    },
    {
        "anchor": "Hypercubic Smeared Links for Dynamical Fermions: We investigate a variant of hypercubic gauge link smearing where the SU(3)\nprojection is replaced with a normalization to the corresponding unitary group.\nThis smearing is differentiable and thus suitable for use in dynamical fermion\nsimulations using molecular dynamics type algorithms. We show that this\nsmearing is as efficient as projected hypercubic smearing in removing\nultraviolet noise from the gauge fields. We test the normalized hypercubic\nsmearing in dynamical improved (clover) Wilson and valence overlap simulations.",
        "positive": "The Nuclear Yukawa Model on a Lattice: We present the results of the quantum field theory approach to nuclear Yukawa\nmodel obtained by standard lattice techniques. We have considered the simplest\ncase of two identical fermions interacting via a scalar meson exchange.\nCalculations have been performed using Wilson fermions in the quenched\napproximation. We found the existence of a critical coupling constant above\nwhich the model cannot be numerically solved. The range of the accessible\ncoupling constants is below the threshold value for producing two-body bound\nstates. Two-body scattering lengths have been obtained and compared to the non\nrelativistic results."
    },
    {
        "anchor": "Finite Size Scaling of Probability Distributions in SU(2) Lattice Gauge\n  Theory and Phi^4 Field Theory: For a system near a second order phase transition, the probability\ndistribution for the order parameter can be given a finite size scaling form.\nThis fact is used to compare the finite temperature phase transition for the\nWilson lines in d=3+1 SU(2) lattice gauge theory with the phase transition in\nd=3 phi^4 field theory. I exhibit the finite size scaled probability\ndistributions in the form of a function of two variables (the reduced\n`temperature' and the magnetization) for both models. The two surfaces look\nidentical, and an analysis of the errors also suggests that they are the same.\nThis strengthens the idea that the SU(2) effective line theory is in the Ising\nuniversality class. I argue for the wider application of the method used here.",
        "positive": "The Staggered Fermion for the Gross-Neveu Model at Non-zero Temperature\n  and Density: The 2+1d Gross-Neveu model with finite density and finite temperature are\nstudied by the staggered fermion discretization. The kinetic part of this\nstaggered fermion in momentum space is used to build the relation between the\nstaggered fermion and Wilson-like fermion. In the large Nf limit (the number Nf\nof staggered fermion flavors), the chiral condensate and fermion density are\nsolved from the gap equation in momentum space, and thus the phase diagram of\nfermion coupling, temperature and chemical potential are obtained. Moreover, an\nanalytic formula for the inverse of the staggered fermion matrix are given\nexplicitly, which can be calculated easily by parallelization. The\ngeneralization to the 1+1d and 3+1d cases are also considered."
    },
    {
        "anchor": "Center Vortices and Chiral Symmetry Breaking in SU(2) Lattice Gauge\n  Theory: We investigate the chiral properties of near-zero modes for thick classical\ncenter vortices in SU (2) lattice gauge theory as examples of the phenomena\nwhich may arise in a vortex vacuum. In particular we analyze the creation of\nnear-zero modes from would-be zero modes of various topological charge\ncontributions from center vortices. We show that classical colorful spherical\nvortex and instanton ensembles have almost identical Dirac spectra and the\nlow-lying eigenmodes from spherical vortices show all characteristic properties\nfor chiral symmetry breaking. We further show that also vortex intersections\nare able to give rise to a finite density of near-zero modes, leading to chiral\nsymmetry breaking via the Banks-Casher formula. We discuss the mechanism by\nwhich center vortex fluxes contribute to chiral symmetry breaking.",
        "positive": "Polyakov loop in 2+1 flavor QCD: We study the temperature dependence of the renormalized Polyakov loop in 2+1\nflavor QCD for temperatures T<210 MeV. We extend previous calculations by the\nHotQCD collaboration using the highly improved staggered quark action and\nperform a continuum extrapolation of the renormalized Polyakov loop. We compare\nthe lattice results with the prediction of non-interacting static-light hadron\nresonance gas, which describes the temperature dependence of the renormalized\nPolyakov loop up to T<140 MeV but fails above that temperature. Furthermore, we\ndiscuss the temperature dependence of the light and strange quark condensates."
    },
    {
        "anchor": "B-parameters of the complete set of matrix elements of (Delta B = 2)\n  operators from the lattice: We compute on the lattice the ``bag'' parameters of the five (Delta B = 2)\noperators of the supersymmetric basis, by combining their values determined in\nfull QCD and in the static limit of HQET. The extrapolation of the QCD results\nfrom the accessible heavy-light meson masses to the B-meson mass is constrained\nby the static result. The matching of the corresponding results in HQET and in\nQCD is for the first time made at NLO accuracy in the MSbar(NDR)\nrenormalization scheme. All results are obtained in the quenched approximation.",
        "positive": "The principle of indirect elimination: The principle of indirect elimination states that an algorithm for solving\ndiscretized differential equations can be used to identify its own\nbad-converging modes. When the number of bad-converging modes of the algorithm\nis not too large, the modes thus identified can be used to strongly improve the\nconvergence. The method presented here is applicable to any standard algorithm\nlike Conjugate Gradient, relaxation or multigrid. An example from theoretical\nphysics, the Dirac equation in the presence of almost-zero modes arising from\ninstantons, is studied. Using the principle, bad-converging modes are removed\nefficiently. Applied locally, the principle is one of the main ingredients of\nthe Iteratively Smooting Unigrid algorithm."
    },
    {
        "anchor": "Microscopic Encoding of Macroscopic Universality: Scaling Properties of\n  Dirac Eigenspectra near QCD Chiral Phase Transition: Macroscopic properties of the strong interaction near its chiral phase\ntransition exhibit scaling behaviors, which are the same as those observed\nclose to the magnetic transition in a 3-dimensional classical spin system with\n$O(4)$ symmetry. We show that the universal scaling properties of the chiral\nphase transition in Quantum Chromodynamics (QCD) at the macroscale are, in\nfact, encoded within the microscopic energy levels of its fundamental\nconstituents, the quarks. We establish a connection between the cumulants of\nthe chiral order parameter, i.e., the chiral condensate, and the correlations\namong the energy levels of quarks, i.e., the eigenspectra of the massless QCD\nDirac operator. This relation elucidates how the fluctuations of the chiral\ncondensate arise from the correlations within the infrared part of the energy\nspectra of quarks, and naturally leads to a generalization of the Banks-Casher\nrelation for the cumulants of the chiral condensate. Then, through (2+1)-flavor\nlattice QCD calculations with varying light quark masses near the QCD chiral\ntransition, we demonstrate that the correlations among the infrared part of the\nDirac eigenvalue spectra exhibit same universal scaling behaviors as expected\nof the cumulants of the chiral condensate. We find that these universal scaling\nbehaviors extend up to the physical values of the up and down quark masses. Our\nstudy reveals how the hidden scaling features at the microscale give rise to\nthe macroscopic universal properties of QCD.",
        "positive": "High Precision Renormalization Group Study of the Roughening Transition: We confirm the Kosterlitz-Thouless scenario of the roughening transition for\nthree different Solid-On-Solid models: the Discrete Gaussian model, the\nAbsolute-Value-Solid-On-Solid model and the dual transform of the XY model with\nstandard (cosine) action. The method is based on a matching of the\nrenormalization group flow of the candidate models with the flow of a bona fide\nKT model, the exactly solvable BCSOS model. The Monte Carlo simulations are\nperformed using efficient cluster algorithms. We obtain high precision\nestimates for the critical couplings and other non-universal quantities. For\nthe XY model with cosine action our critical coupling estimate is\n$\\beta_R^{XY}=1.1197(5)$. For the roughening coupling of the Discrete Gaussian\nand the Absolute-Value-Solid-On-Solid model we find $K_R^{DG}=0.6645(6)$ and\n$K_R^{ASOS}=0.8061(3)$, respectively."
    },
    {
        "anchor": "Solution of symmetry equation and hierarchy of self dual Yang-Mills\n  systems: The solution of symmetry equation of Yang-Mills self dual system is found in\nexplicit form of its raising Hamiltonian operator. Thus explicit form of\nequations of self dual Yang Mills hierarchy is constructed.",
        "positive": "Renormalization functions for Nf=2 and Nf=4 Twisted Mass fermions: We present results on the renormalization functions of the quark field and\nfermion bilinears with up to one covariant derivative. For the fermion part of\nthe action we employ the twisted mass formulation with $N_f{=}2$ and $N_f{=}4$\ndegenerate dynamical quarks, while in the gluon sector we use the Iwasaki\nimproved action. The simulations for $N_f{=}4$ have been performed for pion\nmasses in the range of 390MeV - 760MeV and at three values of the lattice\nspacing, $a$, corresponding to $\\beta{=}1.90,\\,1.95,\\,2.10$. The $N_f{=}2$\naction includes a clover term with $c_{\\rm sw}{=}1.57551$ at $\\beta{=}2.10$,\nand three ensembles at different values of $m_\\pi$.\n  The evaluation of the renormalization functions is carried out in the RI$'$\nscheme using a momentum source. The non-perturbartive evaluation is\ncomplemented with a perturbative computation, which is carried out at one-loop\nlevel and to all orders in the lattice spacing, $a$. For each renormalization\nfunction computed non-perturbatively we subtract the corresponding lattice\nartifacts to all orders in $a$, so that a large part of the cut-off effects is\neliminated.\n  The renormalization functions are converted to the ${\\overline{\\rm MS}}$\nscheme at a reference energy scale of $\\mu{=}2$ GeV after taking the chiral\nlimit."
    },
    {
        "anchor": "On the convergence of the chiral expansion for the baryon ground-state\n  masses: We study the chiral expansion of the baryon octet and decuplet masses in the\nisospin limit. It is illustrated that a chiral expansion of the one-loop\ncontributions is rapidly converging up to quark masses that generously\nencompasses the mass of the physical strange quark. We express the successive\norders in terms of physical meson and baryon masses. In addition, owing to\nspecific correlations amongst the chiral moments, we suggest a reordering of\nterms that make the convergence properties more manifest. Explicit expressions\nup to chiral order five are derived for all baryon masses at the one-loop\nlevel. The baryon masses obtained do not depend on the renormalization scale.\nOur scheme is tested against QCD lattice data, where the low-energy parameters\nare systematically correlated by large-Nc sum rules. A reproduction of the\nbaryon masses from PACS-CS, LHPC, HSC, NPLQCD, QCDSF-UKQCD and ETMC is achieved\nfor ensembles with pion and kaon masses smaller than 600 MeV. Predictions for\nbaryon masses on ensembles from CLS as well as all low-energy constants that\nenter the baryon masses at N3LO are made.",
        "positive": "Charged particles interaction in both a finite volume and a uniform\n  magnetic field II: topological and analytic properties of a magnetic system: In present work, we discuss some topological features of charged particles\ninteracting a uniform magnetic field in a finite volume. The edge state\nsolutions are presented, as a signature of non-trivial topological systems, the\nenergy spectrum of edge states show up in the gap between allowed energy bands.\nBy treating total momentum of two-body system as a continuous distributed\nparameter in complex plane, the analytic properties of solutions of finite\nvolume system in a magnetic field is also discussed."
    },
    {
        "anchor": "Axial couplings of heavy hadrons from domain-wall lattice QCD: We calculate matrix elements of the axial current for static-light mesons and\nbaryons in lattice QCD with dynamical domain wall fermions. We use partially\nquenched heavy hadron chiral perturbation theory in a finite volume to extract\nthe axial couplings g_1, g_2, and g_3 from the data. These axial couplings\nallow the prediction of strong decay rates and enter chiral extrapolations of\nmost lattice results in the b sector. Our calculations are performed with two\nlattice spacings and with pion masses down to 227 MeV.",
        "positive": "I=2 Pion Scattering Phase Shift with Wilson Fermions: We present a lattice QCD calculation of the scattering phase shift for the\nI=2 $S$-wave two-pion system using the finite size method proposed by\nL\\\"uscher. We work in the quenched approximation employing the standard\nplaquette action at $\\beta=5.9$ for gluons and the Wilson fermion action for\nquarks. The phase shift is extracted from the energy eigenvalues of the\ntwo-pion system, which are obtained by a diagonalization of the pion 4-point\nfunction evaluated for a set of relative spatial momenta. In order to change\nmomentum of the two-pion system, calculations are carried out on $24^3\\times\n60$, $32^3\\times 60$, and $48^3\\times 60$ lattices. The phase shift is\nsuccessfully calculated over the momentum range $0 < p^2 < 0.3 {\\rm GeV}^2$."
    },
    {
        "anchor": "Improved determination of $B_K$ with staggered quarks: We present results for the kaon mixing parameter $B_K$ obtained using\nimproved staggered fermions on a much enlarged set of MILC asqtad lattices.\nCompared to our previous publication, which was based largely on a single\nensemble at each of the three lattice spacings $a\\approx 0.09\\;$fm, $0.06\\;$fm\nand $0.045\\;$fm, we have added seven new fine and four new superfine ensembles,\nwith a range of values of the light and strange sea-quark masses. We have also\nincreased the number of measurements on one of the original ensembles. This\nallows us to do controlled extrapolations in the light and strange sea-quark\nmasses, which we do simultaneously with the continuum extrapolation. This\nreduces the extrapolation error and improves the reliability of our error\nestimates. Our final result is $\\hat{B}_K = 0.7379 \\pm 0.0047 (\\text{stat}) \\pm\n0.0365 (\\text{sys})$.",
        "positive": "A lattice study of light scalar tetraquarks with isopins 0, 1/2 and 1: The observed mass pattern of scalar resonances below 1 GeV gives preference\nto the tetraquark assignment over the conventional $\\bar qq$ assignment for\nthese states. We present a search for tetraquarks with isospins 0,1/2,1 in\nlattice QCD, where isospin channels 1/2 and 1 have not been studied before. Our\nsimulation uses Chirally Improved fermions on quenched gauge configurations. We\ndetermine three energy levels for each isospin using the variational method.\nThe ground state is consistent with the scattering state, while the two excited\nstates have energy above 2 GeV. Therefore we find no indication for light\ntetraquarks at our range of pion masses 344-576 MeV."
    },
    {
        "anchor": "SYM on the lattice: Non-perturbative predictions and numerical simulations in supersymmetric\nYang-Mills (SYM) theories are reviewed.",
        "positive": "Strong coupling expansion Monte Carlo: We give an overview on recently accomplished successful generalizations of\n`worm' or loop gas simulation methods to O(N) and CP(N-1) sigma models and to\nsimple fermion models. Beside the advantage of (practically) eliminated\ncritical slowing down we also explain additional opportunities to estimate some\nobservables with extremely improved signal to noise levels."
    },
    {
        "anchor": "Frequency-splitting estimators for single-propagator traces: In these proceedings we address the computation of quark-line disconnected\ndiagrams in lattice QCD. The evaluation of these diagrams is required for many\nphenomenologically interesting observables, but suffers from large statistical\nerrors due to the vacuum and random-noise contributions to their variances.\nMotivated by a theoretical analysis of the variances, we introduce a new family\nof stochastic estimators of single-propagator traces built upon a frequency\nsplitting combined with a hopping expansion of the quark propagator, and test\ntheir efficiency in two-flavour QCD with pions as light as 190 MeV. The use of\nthese estimators reduces the cost of the computation by one to two orders of\nmagnitude over standard estimators depending on the fermion bilinear. As a\nconcrete application, we show the impact of these findings on the computation\nof the hadronic vacuum polarization contribution to the muon anomalous magnetic\nmoment.",
        "positive": "Monopoles of the Dirac type and color confinement in QCD: We present results of $SU(3)$ Monte-Carlo studies of a new color confinement\nscheme proposed recently due to Abelian-like monopoles of the Dirac type\ncorresponding in the continuum limit to violation of the non-Abelian Bianchi\nidentities (VNABI). The simulations are done without any additional\ngauge-fixing smoothing the vacuum. We get for the first time, in pure $SU(3)$\nsimulations with the standard Wilson action, (1) the perfect Abelian dominance\nwith respect to the static potentials on $12^4\\sim 16^4$ lattices at\n$\\beta=5.6-5.8$ using the multilevel method. (2) The perfect monopole as well\nas Abelian dominances with respect to the static potentials by evaluating the\nPolyakov loop correlators on $24^3\\times4$ at $\\beta=5.6$. The Abelian photon\npart gives zero string tension. (3) The Abelian dual Meissner effect is\nobserved with respect to the Abelian gauge field and Abelian monopoles. The\nAbelian electric field of a color is squeezed due to the solenoidal monopole\ncurrent with the corresponding color. Although the scaling and the volume\ndependence are not yet studied in $SU(3)$, the present results and the previous\n$SU(2)$ results are consistent with the new Abelian picture of color\nconfinement that each one of eight (three in $SU(2)$) colored electric flux is\nsqueezed by the corresponding colored Abelian-like monopole of the Dirac type\ncorresponding to VNABI."
    },
    {
        "anchor": "Lattice study of conformality in twelve-flavor QCD: We study infrared conformality of the twelve-flavor QCD on the lattice.\nUtilizing the highly improved staggered quarks (HISQ) type action which is\nuseful to study the continuum physics, we analyze the lattice data of the mass\nand the decay constant of a pseudoscalar meson and the mass of a vector meson\nas well at several values of lattice spacing and fermion mass. Our result is\nconsistent with the conformal hypothesis for the mass anomalous dimension\n$\\gamma_m \\sim 0.4-0.5$.",
        "positive": "Center Vortices at Strong Couplings and All Couplings: Motivations for the center vortex theory of confinement are discussed. In\nparticular, it is noted that the abelian dual Meissner effect, which is the\nsignature of dual superconductivity, cannot adequately describe the confining\nforce at large distance scales. A long-range effective action is derived from\nstrong-coupling lattice gauge theory in D=3 dimensions, and it is shown that\ncenter vortices emerge as the stable saddlepoints of this action. Thus, in the\ncase of strong couplings, the vortex picture is arrived at analytically. I also\nrespond briefly to a recent criticism regarding maximal center gauge."
    },
    {
        "anchor": "Dynamical coupled-channel approaches on a momentum lattice: Dynamical coupled-channel approaches are a widely used tool in hadronic\nphysics that allow to analyze different reactions and partial waves in a\nconsistent way. In such approaches the basic interactions are derived within an\neffective Lagrangian framework and the resulting pseudo-potentials are then\nunitarized in a coupled-channel scattering equation. We propose a scheme that\nallows for a solution of the arising integral equation in discretized momentum\nspace for periodic as well as twisted boundary conditions. This permits to\nstudy finite size effects as they appear in lattice QCD simulations. The new\nformalism, at this stage with a restriction to S-waves, is applied to\ncoupled-channel models for the sigma(600), f0(980), and a0(980) mesons, and\nalso for the Lambda(1405) baryon. Lattice spectra are predicted.",
        "positive": "The masses of the mesons and baryons. Part V. The neutrino branch\n  particles: We have determined theoretically the rest mass of the muon neutrino at 50\nmilli-eV and the rest mass of the electron neutrino at 5 meV, as well as, to 1%\naccuracy, the ratio of the masses of the stable elementary particles which\ndecay by weak decays. We assume that the particles of the neutrino branch\nconsist of a cubic, isotropic nuclear lattice, held together by the weak\nnuclear force. The eigenfrequencies of the lattice are calculated with Born's\ntheory of cubic lattices. Only neutrinos are required to explain the so-called\nstable particles of the neutrino branch."
    },
    {
        "anchor": "The Lattice Mean-Field Approximation of Gauge-Higgs Unification on the\n  Orbifold: A possible extension of the Standard Model of elementary particles is\nGauge-Higgs unification, where the Higgs field is identified with (some of) the\nextra dimensional components of a five-dimensional gauge field. In this\nscenario there is evidence for the potential and the mass of the Higgs field to\nbe finite. Here we show the behavior of the static potential of a\nfive-dimensional SU(2) lattice gauge theory with orbifold boundary conditions.\nThe potentials are computed within the mean-field approximation including first\norder corrections.",
        "positive": "Confinement in the Deconfined Phase: A numerical study with a cluster\n  algorithm: We have previously found analytically a very unusual and unexpected form of\nconfinement in SU(3) Yang-Mills theory. This confinement occurs in the\ndeconfined phase of the theory. The free energy of a single static test quark\ndiverges, even though it is contained in deconfined bulk phase and there is no\nQCD string present. This phenomenon occurs in cylindrical volumes with a\ncertain choice of spatial boundary conditions. We examine numerically an\neffective model for the Yang-Mills theory and, using a cluster algorithm, we\nobserve this unusual confinement. We also find a new way to determine the\ninterface tension of domain walls separating distinct bulk phases."
    },
    {
        "anchor": "Reflection Positivity of Free Overlap Fermions: It is shown that free lattice fermions defined by overlap Dirac operator\nfulfill the Osterwalder-Schrader reflection positivity condition with respect\nto the link-reflection. The proof holds true in non-gauge models with\ninteractions such as chiral Yukawa models.",
        "positive": "Strong-coupling expansion of chiral models: The strong-coupling character expansion of lattice models is reanalyzed in\nthe perspective of its complete algorithmization. The geometric problem of\nidentifying, counting, and grouping together all possible contributions is\ndisentangled from the group-theoretical problem of weighting them properly. The\nfirst problem is completely solved for all spin models admitting a\ncharacter-like expansion and for arbitrary lattice connectivity. The second\nproblem is reduced to the evaluation of a class of invariant group integrals\ndefined on simple graphs. Since these integrals only depend on the global\nsymmetry of the model, results obtained for principal chiral models can be used\nwithout modifications in lattice gauge theories. By applying the techniques and\nresults obtained we study the two-dimensional principal chiral models on the\nsquare and honeycomb lattice. These models are a prototype field theory sharing\nwith QCD many properties. Strong-coupling expansions for Green's functions are\nderived up to 15th and 20th order respectively. Large-$N$ and $N=\\infty$\nresults are presented explicitly. Related papers are devoted to a discussion of\nthe results."
    },
    {
        "anchor": "Glueball masses in 2+1 dimensional SU(N) gauge theories with twisted\n  boundary conditions: We analyze 2+1 dimensional Yang-Mills theory regularized on a lattice with\ntwisted boundary conditions in the spatial directions. In previous work it was\nshown that the observables in the non-zero electric flux sectors obey the\nso-called $x$-scaling, i.e. depend only on the dimensionless variable $x\\propto\nNL/b$ and the angle $\\tilde\\theta$ given by the parameters of the twist ($L$\nbeing the length of the spatial torus and $b$ the inverse 't Hooft coupling).\nIt is conjectured that this scaling is obeyed by all physical quantities. In\nthis work we extend the previous analyses to the zero electric flux (glueball)\nsector. We study the mass of the lightest scalar glueball in two theories with\ndifferent $N$ but matching $x$ and $\\tilde\\theta$ in a wide range of couplings\nfrom the perturbative small-volume regime to the non-perturbative one. We find\nthat the results are consistent with the $x$-scaling hypothesis.",
        "positive": "Real-time dynamics of proton decay: Substituting Skyrmion for nucleon, one can potentially see -- in real time --\nhow the monopole is catalysing the proton (or neutron) decay, and even obtain a\nplausible estimate for catalysis cross-section. Here we discuss the key aspects\nof a practical implementation of such approach and demonstrate how one can\novercome the main technical problems: Gauss constraint violation and\nreflections at the boundaries."
    },
    {
        "anchor": "$Z_6$ symmetry, electroweak transition, and magnetic monopoles at high\n  temperature: We consider the lattice realization of the Standard Model with an additional\n$Z_6$ symmetry. Numerical simulations were performed on the asymmetric lattice,\nwhich corresponds to the finite temperature theory. Our choice of parameters\ncorresponds to large Higgs masses ($M_H > 90$ Gev). The phase diagram was\ninvestigated and has been found to be different from that of the usual lattice\nrealization of the Standard Model. It has been found, that the\nconfinement-deconfinement phase transition lines for the SU(2) and SU(3) fields\ncoincide. The transition line between Higgs and symmetric deconfinement parts\nof the phase diagram and the confinement-deconfinement transition line meet in\na triple point. The transition between Higgs and symmetric parts of the phase\ndiagram corresponds to the finite temperature electroweak transition/crossover.\nWe see for the first time evidence that Nambu monopoles are condensed at\n$T>T_c$ while at $T<T_c$ their condensate vanishes.",
        "positive": "Gribov Noise on the Lattice Axial Current Renormalisation Constant: We study the influence of Gribov copies, in the Landau gauge, on the lattice\nrenormalisation constant of the axial current, obtained from a Ward identity on\nquark state correlation functions, with the Clover action, in quenched SU(3)\ngauge theory. A comparison between the gauge invariant determination of the\nrenorma= lization constant and the gauge dependent one is discussed. We find\nthat the residual gauge freedom associated to Gribov copies induces observable\neffects, which, at the level of numerical accuracy of our simulation, are\nincluded in the statistical uncertainty inherent in a Monte Carlo simulation.\nDoubling the statistics suggests that the fluctuation due to the lattice Gribov\nambiguity scales down at least as fast as a pure statistical error."
    },
    {
        "anchor": "The lattice Landau gauge gluon propagator at zero and finite temperature: We study the Landau gauge gluon propagator at zero and finite temperature\nusing lattice simulations. Particular attention is given to the finite size\neffects and to the infrared behaviour.",
        "positive": "Chiral symmetry breaking and monopoles: To understand the relation between the chiral symmetry breaking and\nmonopoles, the chiral condensate which is the order parameter of the chiral\nsymmetry breaking is calculated in the $\\overline{\\mbox{MS}}$ scheme at 2\n[GeV]. First, we add one pair of monopoles, varying the monopole charges\n$m_{c}$ from zero to four, to SU(3) quenched configurations by a monopole\ncreation operator. The low-lying eigenvalues of the Overlap Dirac operator are\ncomputed from the gauge links of the normal configurations and the\nconfigurations with additional monopoles. Next, we compare the distributions of\nthe nearest-neighbor spacing of the low-lying eigenvalues with the prediction\nof the random matrix theory. The low-lying eigenvalues not depending on the\nscale parameter $\\Sigma$ are compared to the prediction of the random matrix\ntheory. The results show the consistency with the random matrix theory. Thus,\nthe additional monopoles do not affect the low-lying eigenvalues. Moreover, we\ndiscover that the additional monopoles increase the scale parameter $\\Sigma$.\nWe then evaluate the chiral condensate in the $\\overline{\\mbox{MS}}$ scheme at\n2 [GeV] from the scale parameter $\\Sigma$ and the renormalization constant\n$Z_{S}$. The final results clearly show that the chiral condensate linearly\ndecreases by increasing the monopole charges."
    },
    {
        "anchor": "Yang-Mills Theory in lambda-Gauges: The gauge-independent phenomenon of color confinement in Yang-Mills theory\nmanifests itself differently in different gauges. Therefore, the gauge\ndependence of quantities related to the infrared structure of the theory\nbecomes important for understanding the confinement mechanism. Particularly\nuseful are classes of gauges that are controlled by a single gauge parameter.\nWe present results on propagators and the color-Coulomb potential for the\nso-called lambda-gauges, which interpolate between the (minimal) Landau gauge\nand the (minimal complete) Coulomb gauge. Results are reported for the SU(2)\nlattice gauge theory in three and four space-time dimensions. We investigate\nespecially intermediate and low momenta. We find a continuous evolution of all\nquantities with the gauge parameter, except at zero four-momentum.",
        "positive": "Critical temperature in QCD with two flavors of dynamical quarks: We present results obtained in QCD with two flavors of non-perturbatively\nimproved Wilson fermions at finite temperature on $16^3 \\times 8$ and $24^3\n\\times 10$ lattices. We determine the transition temperature in the range of\nquark masses $0.6<m_\\pi/m_\\rho<0.8$ at lattice spacing a$\\approx$0.1 fm and\nextrapolate the transition temperature to the continuum and to the chiral\nlimits. We also discuss the order of phase transition."
    },
    {
        "anchor": "Towards a holographic description of cosmology: Renormalisation of the\n  energy-momentum tensor of the dual QFT: In the holographic approach to cosmology, cosmological observables are\ndescribed in terms of correlators of a three-dimensional boundary quantum field\ntheory. As a concrete model, we study the 3$d$ massless $SU(N)$ scalar matrix\nfield theory. In this work, we focus on the renormalisation of the\nenergy-momentum tensor 2-point function, which can be related to the CMB power\nspectra. Here we present a non-perturbative procedure to remove divergences\nresulting from the loss of translational invariance on the lattice, by imposing\nWard identities. This will allow us to make predictions for the CMB power\nspectra in the regime where the dual QFT is non-perturbative.",
        "positive": "Comment on \"Valence QCD: Connecting QCD to the Quark Model\": I criticize certain conclusions about the physics of hadrons drawn from a\n\"valence QCD\" approximation to QCD."
    },
    {
        "anchor": "Center Vortex Model for the Infrared Sector of SU(3) Yang-Mills Theory -\n  Vortex Free Energy: The vortex free energy is studied in the random vortex world-surface model of\nthe infrared sector of SU(3) Yang-Mills theory. The free energy of a center\nvortex extending into two spatial directions, which is introduced into\nYang-Mills configurations when acting with the 't Hooft loop operator, is\nverified to furnish an order parameter for the deconfinement phase transition.\nIt is shown to exhibit a weak discontinuity at the critical temperature,\ncorresponding to the weak first order character of the transition.",
        "positive": "Topological susceptibility in Lattice QCD with unimproved Wilson\n  fermions: We address a long standing problem regarding topology in lattice simulations\nof QCD with unimproved Wilson fermions. Earlier attempt with unimproved Wilson\nfermions at \\beta =5.6 to verify the suppression of topological susceptibility\nwith decreasing quark mass (m_q) was unable to unambiguously confirm the\nsuppression. We carry out systematic calculations for two degenerate flavours\nat two different lattice spacings (\\beta = 5.6 and 5.8). The effects of quark\nmass, lattice volume and the lattice spacing on the spanning of different\ntopological sectors are presented. We unambiguously demonstrate the suppression\nof the topological susceptibility with decreasing quark mass, expected from\nchiral Ward identity and chiral perturbation theory."
    },
    {
        "anchor": "Critical universality and hyperscaling revisited for Ising models of\n  general spin using extended high-temperature series: We have extended through beta^{23} the high-temperature expansion of the\nsecond field derivative of the susceptibility for Ising models of general spin,\nwith nearest-neighbor interactions, on the simple cubic and the body-centered\ncubic lattices. Moreover the expansions for the nearest-neighbor correlation\nfunction, the susceptibility and the second correlation moment have been\nextended up to beta^{25}. Taking advantage of these new data, we can improve\nthe accuracy of direct estimates of critical exponents and of hyper-universal\ncombinations of critical amplitudes such as the renormalized four-point\ncoupling g_r or the quantity usually denoted by R^{+}_{xi}. We have used a\nvariety of series extrapolation procedures and, in some of the analyses, we\nhave assumed that the leading correction-to-scaling exponent theta is universal\nand roughly known. We have also verified, to high precision, the validity of\nthe hyperscaling relation and of the universality property both with regard to\nthe lattice structure and to the value of the spin.",
        "positive": "Nuclear Reactions from Lattice QCD: One of the overarching goals of nuclear physics is to rigorously compute\nproperties of hadronic systems directly from the fundamental theory of strong\ninteractions, Quantum Chromodynamics (QCD). In particular, the hope is to\nperform reliable calculations of nuclear reactions which will impact our\nunderstanding of environments that occur during big bang nucleosynthesis, the\nevolution of stars and supernovae, and within nuclear reactors and high\nenergy/density facilities. Such calculations, being truly ab initio, would\ninclude all two-nucleon and three- nucleon (and higher) interactions in a\nconsistent manner. Currently, lattice QCD provides the only reliable option for\nperforming calculations of some of the low- energy hadronic observables. With\nthe aim of bridging the gap between lattice QCD and nuclear many-body physics,\nthe Institute for Nuclear Theory held a workshop on Nuclear Reactions from\nLattice QCD on March 2013. In this review article, we report on the topics\ndiscussed in this workshop and the path planned to move forward in the upcoming\nyears."
    },
    {
        "anchor": "Hadron Mass Predictions of the Valence Approximation to Lattice QCD: We evaluate the infinite volume, continuum limits of eight hadron mass ratios\npredicted by lattice QCD with Wilson quarks in the valence (quenched)\napproximation. Each predicted ratio differs from the corresponding observed\nvalue by less than 6\\%.",
        "positive": "Casimir boundaries, monopoles, and deconfinement transition in 3+1\n  dimensional compact electrodynamics: Compact U(1) gauge theory in 3+1 dimensions possesses the confining phase,\ncharacterized by a linear raise of the potential between particles with\nopposite electric charges at sufficiently large inter-particle separation. The\nconfinement is generated by condensation of Abelian monopoles at strong gauge\ncoupling. We study the properties of monopoles and the deconfining order\nparameter in zero-temperature theory in the presence of ideally conducting\nparallel metallic boundaries (plates) usually associated with the Casimir\neffect. Using first-principle numerical simulations in compact U(1) lattice\ngauge theory, we show that as the distance between the plates diminishes, the\nvacuum in between the plates experiences a deconfining transition. The phase\ndiagram in the space of the gauge coupling and the inter-plane distance is\nobtained."
    },
    {
        "anchor": "Exploration of SU(N_c) gauge theory with many Wilson fermions at strong\n  coupling: We explore aspects of the phase structure of SU(2) and SU(3) lattice gauge\ntheories at strong coupling with many flavours $N_f$ of Wilson fermions in the\nfundamental representation. The pseudoscalar meson mass as a function of\nhopping parameter is observed to deviate from the expected analytic dependence,\nat least for sufficiently large $N_f$. Implications of this effect are\ndiscussed, including the relevance to recent searches for an infrared fixed\npoint.",
        "positive": "The $D_s$, $D^+$, $B_s$ and $B$ decay constants from $2+1$ flavor\n  lattice QCD: We present a study of the $D$ and $B$ leptonic decay constants on the MILC\n$N_f=2+1$ asqtad gauge ensembles using asqtad-improved staggered light quarks\nand clover heavy quarks in the Fermilab interpretation. Our previous analysis\n\\cite{Bazavov:2011aa} computed the decay constants at lattice spacings $a\n\\approx 0.14, 0.11$ and $0.083$ fm. We have extended the simulations to finer\n$a \\approx 0.058$ and $0.043$ fm lattice spacings, and have also increased\nstatistics; this allows us to address many important sources of uncertainty.\nTechnical advances include a two-step two-point fit procedure, better tuning of\nthe heavy quark masses and a better determination of the axial-vector current\nmatching. The present analysis remains blinded, so here we focus on the\nimprovements and their predicted impact on the error budget compared to the\nprior analysis."
    },
    {
        "anchor": "RI/MOM and RI/SMOM renormalization of quark bilinear operators using\n  overlap fermions: We present the vector, scalar and tensor renormalization constants (RCs)\nusing overlap fermions with either regularization independent momentum\nsubtraction (RI/MOM) or symmetric momentum subtraction (RI/SMOM) as the\nintermediate scheme on the lattice with lattice spacings $a$ from 0.04 fm to\n0.12 fm. Our gauge field configurations from the MILC and RBC/UKQCD\ncollaborations include sea quarks using either the domain wall or the HISQ\naction, respectively. The results show that RI/MOM and RI/SMOM can provide\nconsistent renormalization constants to the $\\overline{\\textrm{MS}}$ scheme,\nafter proper $a^2p^2$ extrapolations. But at $p\\sim 2$\\,GeV, both RI/MOM and\nRI/SMOM suffer from nonperturbative effects which cannot be removed by the\nperturbative matching. The comparison between the results with different sea\nactions also suggests that the renormalization constant is discernibly\nsensitive to the lattice spacing but not to the bare gauge coupling in the\ngauge action.",
        "positive": "Signal/noise optimization strategies for stochastically estimated\n  correlation functions: Numerical studies of quantum field theories usually rely upon an accurate\ndetermination of stochastically estimated correlation functions in order to\nextract information about the spectrum of the theory and matrix elements of\noperators. The reliable determination of such correlators is often hampered by\nan exponential degradation of signal/noise at late time separations. We\ndemonstrate that it is sometimes possible to achieve significant enhancements\nof signal/noise by appropriately optimizing correlators with respect to the\nsource and sink interpolating operators, and highlight the large range of\npossibilities that are available for this task. The ideas are discussed for\nboth a toy model, and single hadron correlators in the context of quantum\nchromodynamics."
    },
    {
        "anchor": "Interpretation of topologically restricted measurements in lattice\n  sigma-models: We consider models with topological sectors, and difficulties with their\nMonte Carlo simulation. In particular we are concerned with the situation where\na simulation has an extremely long auto-correlation time with respect to the\ntopological charge. Then reliable numerical measurements are possible only\nwithin single topological sectors. The challenge is to assemble such restricted\nmeasurements to obtain an approximation for the full-fledged result, which\ncorresponds to the correct sampling over the entire set of configurations.\nUnder certain conditions this is possible, and it provides in addition an\nestimate for the topological susceptibility chi_t. Moreover, the evaluation of\nchi_t might be feasible even from data in just one topological sector, based on\nthe correlation of the topological charge density. Here we present numerical\ntest results for these techniques in the framework of non-linear sigma-models.",
        "positive": "Analysis of the scalar mesons on the Lattice: We study the possibility that the scalar mesons exist as four-quark states.\nThe energy shift of two pseudoscalar mesons as a function of spatial lattice\nsize makes a distinction between bound states and scattering states of\nfour-quark states. We calculate the four-quark state in the quenched\napproximation, ignoring the two-quark annihilation diagrams and the vacuum\nchannels. We perform a calculation of pseudoscalar meson scattering amplitudes,\nusing N_f=2 Wilson fermion and plaquette/Iwasaki gauge actions. We obtain the\nindication that the four-quark states in the case of the isospin zero (I=0) and\ntwo (I=2) channels are no bound states. And we find that the bound energy\ndepends strongly on pion mass rather than the ratio of pion mass to rho meson\nmass."
    },
    {
        "anchor": "Nucleon form factors and root-mean-square radii on a (10.8 fm$)^4$\n  lattice at the physical point: We present the nucleon form factors and root-mean-square (RMS) radii measured\non a (10.8 fm$)^4$ lattice at the physical point. We compute the form factors\nat small momentum transfer region in $q^2\\le 0.102$ GeV$^2$ with the standard\nplateau method choosing four source-sink separation times $t_{\\rm sep}$ from\n0.84 to 1.35 fm to examine the possible excited state contamination. We obtain\nthe electric and magnetic form factors and their RMS radii for not only the\nisovector channel but also the proton and neutron ones without the disconnected\ndiagram. We also obtain the axial-vector coupling and the axial radius from the\naxial-vector form factor. We find that these three form factors do not show\nlarge $t_{\\rm sep}$ dependence in our lattice setup. On the other hand, the\ninduced pseudoscalar and pseudoscalar form factors show the clear effects of\nthe excited state contamination, which affect the generalized\nGoldberger-Treiman relation.",
        "positive": "Measuring Diquark Condensation in Lattice Simulations of Dense Matter: We discuss general aspects of the possibility of Bose condensation of diquark\npairs in systems of dense matter. Lattice field theory simulations are\npresented for model four-fermion theories which are expected to manifest the\nphenomenon, and results from measurements of both diquark two-point and\none-point functions presented. Whilst initial results are promising, there\nremain systematic effects needing to be understood."
    },
    {
        "anchor": "Taste violations in the scalar correlator in mixed action simulations: We study the behavior of the isovector scalar correlator, which is\nparticularly sensitive to lattice artifacts, using domain-wall valence quarks\non a staggered sea (generated by the MILC collaboration). We analyze this\naccording to the prediction from chiral perturbation theory determined by\nPrelovsek, which indicates that the leading unitarity violations come from\ntaste breaking effects. We show that our data behaves in the way predicted by\nPrelovsek, thus verifying that the largest contribution to the violations of\nunitarity which arise at finite lattice spacing can be described by the\nmixed-action chiral perturbation theory.",
        "positive": "B0-B0bar mixing in the static approximation from the Schroedinger\n  Functional and twisted mass QCD: We discuss the renormalisation properties of parity-odd Delta B=2 operators\nwith the heavy quark treated in the static approximation. Via twisted mass QCD\n(tmQCD), these operators provide the matrix elements relevant for the B0-B0bar\nmixing amplitude. The layout of a non-perturbative renormalisation programme\nfor the operator basis, using Schroedinger Functional techniques, is described.\nFinally, we report our results for a one-loop perturbative study of various\nrenormalisation schemes with Wilson-type lattice regularisations, which allows,\nin particular, to compute the NLO anomalous dimensions of the operators in the\nSF schemes of interest."
    },
    {
        "anchor": "Virtual Bond Percolation for Ising Cluster Dynamics: The Fortuin-Kasteleyn mapping between the Ising model and the site-bond\ncorrelated percolation model is shown to be only one of an infinite class of\nexact mappings. These new cluster representations are a result of\n\"renormalized\" percolation rules correlated to entire blocks of spins. For\nexample these rules allow for percolation on \"virtual\" bonds between spins not\npresent in the underlying Hamiltonian. As a consequence we can define new\nrandom cluster theories each with its own Monte Carlo cluster dynamics that\nexactly reproduce the Ising model. By tuning parameters on the critical\npercolation surface, it is demonstrated numerically that cluster algorithms can\nbe formulated for the 2-d and 3-d Ising model that have smaller\nautocorrelations than the original Swendsen-Wang algorithm.",
        "positive": "On the strange quark mass with improved staggered quarks: We present results on the sum of the masses of light and strange quark using\nimproved staggered quarks. Our calculation uses 2+1 flavours of dynamical\nquarks. The effects of the dynamical quarks are clearly visible."
    },
    {
        "anchor": "Scaling in Steiner Random Surfaces: It has been suggested that the modified Steiner action functional has\ndesirable properties for a random surface action. In this paper we investigate\nthe scaling of the string tension and massgap in a variant of this action on\ndynamically triangulated random surfaces and compare the results with the\ngaussian plus extrinsic curvature actions that have been used previously.",
        "positive": "Study of gauge (in)dependence of monopole dynamics: We investigated the gauge (in)dependence of the confinement mechanism due to\nmonopole condensation in SU(2) lattice QCD by various abelian projections. We\nfound (1) the string tension can be reproduced by monopoles alone also in\nPolyakov gauge and (2) the behaviors of the Polyakov loop at the critical\ntemperature seem to be explained by the uniformity breaking of the monopole\ncurrents in every gauge."
    },
    {
        "anchor": "Exotic and conventional mesons from lattice: Recent results on meson spectroscopy from lattice QCD are reviewed. The\nemphasis is on interesting states near thresholds like $Z_c^+(3900)$, $X(3872)$\nand $D_{s0}^*(2317)$. Another focus is on the meson resonances in light,\nstrange and charm sector, where the resonance masses as well as the strong\ndecay widths are extracted from the lattice.",
        "positive": "Nucleon axial coupling from Lattice QCD: We present state-of-the-art results from a lattice QCD calculation of the\nnucleon axial coupling, $g_A$, using M\\\"obius Domain-Wall fermions solved on\nthe dynamical $N_f = 2 + 1 + 1$ HISQ ensembles after they are smeared using the\ngradient-flow algorithm. Relevant three-point correlation functions are\ncalculated using a method inspired by the Feynman-Hellmann theorem, and\ndemonstrate significant improvement in signal for fixed stochastic samples. The\ncalculation is performed at five pion masses of $m_\\pi\\sim \\{400, 350, 310,\n220, 130\\}$~MeV, three lattice spacings of $a\\sim\\{0.15, 0.12, 0.09\\}$~fm, and\nwe do a dedicated volume study with $m_\\pi L\\sim\\{3.22, 4.29, 5.36\\}$. Control\nover all relevant sources of systematic uncertainty are demonstrated and\nquantified. We achieve a preliminary value of $g_A = 1.285(17)$, with a\nrelative uncertainty of 1.33\\%."
    },
    {
        "anchor": "Measurement of hadron masses in 2-color finite density QCD: We investigate hadron spectra in 2-color QCD using lattice simulation with\n$N_{f}=2$ at low temperature and finite density in which there appears not only\nthe hadronic phase but also the superfluid phase. We first calculate the pion\nand rho meson spectrum, which is well-known from previous works. The spectral\nordering of these mesons flips around the quark chemical potential\n$\\mu=m^{0}_{\\pi}/2$ ($m^{0}_{\\pi}$: the pion mass at $\\mu=0$), where the phase\ntransition between the hadronic and superfluid phases occurs. For $\\mu \\gtrsim\nm^{0}_{\\pi}/2$, the effective mass for the pion linearly increases while the\none for the rho meson monotonically decreases. Furthermore, we measure hadron\nspectra with the isospin $I=0$ and the angular momentum $J^{P}=0^{\\pm}$. The\neffective masses for the meson, diquark, and antidiquark with the same quantum\nnumber become degenerate just below $\\mu = m^{0}_{\\pi}/2$, and the three\nhadrons have the same mass in the superfluid phase. It suggests that mixing\noccurs between spectra associating with mesons and baryons due to the\n$U(1)_{B}$ symmetry breaking. This phenomenon can be explained in the linear\nsigma model with the approximate $SU(4)$ Pauli-Gursey symmetry.",
        "positive": "Quenched Static force from generalized Wilson loops with gradient flow: We compute the static force on the lattice in the quenched case directly\nthrough generalized Wilson loops. We modify the Wilson loop by inserting an\n$E$-field component on one of the temporal Wilson lines. However, chromo-field\ncomponents prevent us from performing the continuum limit properly, hence, we\nuse gradient flow to renormalize the field insertion. As a result, we obtain\ncontinuum results and compare them to perturbative expression to extract\n$\\Lambda_0$, and we predict the value $\\sqrt{8t_0}\n\\Lambda_{\\overline{\\textrm{MS}}}^{n_f=0} =0.629^{+22}_{-26}$. This work serves\nas preparation for similar operators with field insertions required in\nnonrelativistic effective field theories."
    },
    {
        "anchor": "Phase structure of twisted Eguchi-Kawai model: Twisted Eguchi-Kawai model is a useful tool for studying the large-N gauge\ntheory. It can also provide a nonperturbative formulation of the gauge theory\non noncommutative spaces. Recently it was found that the Z_N^4 symmetry in this\nmodel, which is crucial for the above applications, can break spontaneously in\nthe intermediate coupling region. In this article, we study the phase structure\nof this model using the Monte-Carlo simulation. In particular, we elaborately\ninvestigate the symmetry breaking point from the weak coupling side. The\nsimulation results show that we cannot take a continuum limit for this model.",
        "positive": "Decorrelating Topology with HMC: The investigation of the decorrelation efficiency of the HMC algorithm with\nrespect to vacuum topology is a prerequisite for trustworthy full QCD\nsimulations, in particular for the computation of topology sensitive\nquantities. We demonstrate that for mpi/mrho ratios <= 0.69 sufficient\ntunneling between the topological sectors can be achieved, for two flavours of\ndynamical Wilson fermions close to the scaling region beta=5.6. Our results are\nbased on time series of length 5000 trajectories."
    },
    {
        "anchor": "Progress in Simulations with Twisted Mass Fermions at the Physical Point: In this contribution, results from $N_f=2$ lattice QCD simulations at one\nlattice spacing using twisted mass fermions with a clover term at the physical\npion mass are presented. The mass splitting between charged and neutral pions\n(including the disconnected contribution) is shown to be around\n$20(20)~\\mathrm{MeV}$. Further, a first measurement using the clover twisted\nmass action of the average momentum fraction of the pion is given. Finally, an\nanalysis of pseudoscalar meson masses and decay constants is presented\ninvolving linear interpolations in strange and charm quark masses. Matching to\nmeson mass ratios allows the calculation of quark mass ratios:\n$\\mu_s/\\mu_l=27.63(13)$, $\\mu_c/\\mu_l=339.6(2.2)$ and $\\mu_c/\\mu_s=12.29(10)$.\nFrom this mass matching the quantities $f_K=153.9(7.5)~\\mathrm{MeV}$,\n$f_D=219(11)~\\mathrm{MeV}$, $f_{D_s}=255(12)~\\mathrm{MeV}$ and\n$M_{D_s}=1894(93)~\\mathrm{MeV}$ are determined without the application of\nfinite volume or discretization artefact corrections and with errors dominated\nby a preliminary estimate of the lattice spacing.",
        "positive": "Equation of state in (2+1) flavor QCD at high temperatures: We calculate the Equation of State at high temperatures in (2+1) flavor QCD\nusing the highly improved staggered quark (HISQ) action. We study the lattice\nspacing dependence of the pressure at high temperatures using lattices with\ntemporal extent $N_{\\tau}=6,~8,~10$ and $12$ and perform continuum\nextrapolations. We also give a continuum estimate for the Equation of State up\nto temperatures $T=2\\,$GeV, which are then compared with results of the\nweak-coupling calculations. We find reasonable agreement with the HTL\ncalculation at the highest temperatures and a tension with the EQCD calculation\nof a few percent, with the lattice results in the middle between both."
    },
    {
        "anchor": "Nonperturbative tests of the renormalization of mixed clover-staggered\n  currents in lattice QCD: The Fermilab Lattice and MILC collaborations have shown in one-loop lattice\nQCD perturbation theory that the renormalization constants of vector and\naxial-vector mixed clover-asqtad currents are closely related to the product of\nthose for clover-clover and asqtad-asqtad (local) vector currents. To be useful\nfor future higher precision calculations this relationship must be valid beyond\none-loop and very general. We test its validity nonperturbatively using clover\nand Highly Improved Staggered (HISQ) strange quarks, utilising the absolute\nnormalization of the HISQ temporal axial current. We find that the\nrenormalization of the mixed current differs from the square root of the\nproduct of the pure HISQ and pure clover currents by $2-3\\%$. We also compare\ndiscretization errors between the clover and HISQ formalisms.",
        "positive": "Perturbative two- and three-loop coefficients from large beta Monte\n  Carlo: Perturbative coefficients for Wilson loops and the static quark self-energy\nare extracted from Monte Carlo simulations at large beta on finite volumes,\nwhere all the lattice momenta are large. The Monte Carlo results are in\nexcellent agreement with perturbation theory through second order. New results\nfor third order coefficients are reported. Twisted boundary conditions are used\nto eliminate zero modes and to suppress Z_3 tunneling."
    },
    {
        "anchor": "The Leptonic Decay Constants of $\\bar{Q}q$ Mesons and the Lattice\n  Resolution: We present a high statistics study of the leptonic decay constant $f_P$ of\nheavy pseudoscalar mesons using propagating heavy Wilson quarks within the\nquenched approximation, on lattices covering sizes from about 0.7~fm to 2~fm.\nVarying $\\beta$ between 5.74 and 6.26 we observe a sizeable $a$ dependence of\n$f_P$ when one uses the quark field normalization that was suggested by\nKronfeld and Mackenzie, compared with the weaker dependence observed for the\nstandard relativistic norm. The two schemes come into agreement when one\nextrapolates to $a \\rightarrow 0$. The extrapolations needed to reach the\ncontinuum quantity $f_B$ introduce large errors and lead to the value\n$f_B=0.18(5)$~GeV in the quenched approximation. This suggests that much more\neffort will be needed to obtain an accurate lattice prediction for $f_B$.",
        "positive": "Chiral transition and deconfinement in QCD: The study of QCD with two light dynamical fermions is of fundamental\nimportance to understand the mechanism of color confinement. We present results\nof a numerical investigation on the order of the chiral phase transition with\n$N_f = 2$ by use of a novel strategy in finite size scaling analysis. We\ncompare the critical behaviour of the specific heat, of the chiral\nsusceptibility and of the equation of state with the possible critical\nbehaviours. A second order transition in the O(4) and O(2) universality classes\nare excluded by our data and substantial evidence emerges for a first order\ntransition. Like in most of previous works we have used the standard staggered\naction with $L_t = 4$: possible scaling violations and the need for further\nstudies are discussed."
    },
    {
        "anchor": "Three neutrons from Lattice QCD: We present a study on ab-initio calculations of three-neutron correlators\nfrom Lattice QCD. We extend the method of baryon blocks to systems of three\nspacially displaced baryons. This allows the measurement of three-neutron\n$p$-wave correlators with total spin $S=1/2$ and $3/2$. In addition, we use\nautomatic code generation that has high flexibility and allows for easy\ninclusion of additional channels in the future while optimizing the evaluation\nof contractions. Our measurements were performed on a newly generated $96\\times\n48^3$ Clover-Wilson gauge field ensemble with $m_{\\pi} \\approx\n370\\,\\text{MeV}$. We present preliminary results of our calculations of one\npion and nucleon as well as two nucleon ($2N$) and three neutron ($3n$)\ncorrelators.",
        "positive": "Two body scattering length of Yukawa model on a lattice: The extraction of scattering parameters from Euclidean simulations of a\nYukawa model in a finite volume with periodic boundary conditions is analyzed\nboth in non relativistic quantum mechanics and in quantum field theory."
    },
    {
        "anchor": "Solving the Dirac equation on QPACE: We discuss the implementation and optimization challenges for a Wilson-Dirac\nsolver with Clover term on QPACE, a parallel machine based on Cell processors\nand a torus network. We choose the mixed-precision Schwarz preconditioned FGCR\nalgorithm in order to circumvent network bandwidth and latency constraints, to\nmake efficient use of the multicore parallelism and on-chip memory, and to\nachieve flexibility in the choice of lattice sizes. We present benchmarks on up\nto 256 QPACE nodes showing an aggregate sustained performance of about 10\nTFlops for the complete solver and very good scaling.",
        "positive": "Roberge-Weiss transitions at imaginary isospin chemical potential: At finite imaginary values of the chemical potential, QCD is free of the sign\nproblem. Moreover, at high temperatures the partition function exhibits a new\nsymmetry (the Roberge-Weiss symmetry) connecting phases with different\norientations of the Polyakov loop, and the corresponding phase transitions\nbetween these. In this contribution we investigate the perturbative one-loop\neffective potential for the Polyakov loop in the presence of imaginary isospin\nas well as baryon chemical potentials. This leads to a novel phase diagram,\nwhich reveals an interesting insight about the rich phase structure of the\nsystem and the center symmetry breaking. We check the perturbative results\nusing direct lattice simulations."
    },
    {
        "anchor": "Resonance parameters of the rho-meson from asymmetrical lattices: We present a lattice QCD calculation of the parameters of the $\\rho$ meson\ndecay. The study is carried out on spatially asymmetric boxes using\nnHYP-smeared clover fermions with two mass-degenerate quark flavors. Our\ncalculations are carried out at a pion mass $m_\\pi=304(2)$ MeV on the set of\nlattices $V=24^2\\times \\eta 24\\times48$ with $\\eta=1.0,1.25$, and 2.0 with\nlattice spacing $a=0.1255(7)$ fm. The resonance mass $m_\\rho=827(3)(5)$ MeV and\ncoupling constant $g_{\\rho\\pi\\pi}=6.67(42)$ are calculate using the P-wave\nscattering phase shifts. We construct a 2$\\times$2 correlation matrix to\nextract the energy of the scattering states and compute the phase shifts using\nthe finite volume formula. By varying the degree of asymmetry, we are able to\ncompute a set of phase shifts that are evenly distributed throughout the\nspectral region where the $\\rho$ decays.",
        "positive": "Non-commutative Solitons in Finite Quantum Mechanics: We construct the unitary evolution operators that realize the quantization of\nlinear maps of SL(2,R) over phase spaces of arbitrary integer discretization N\nand show the non-trivial dependence on the arithmetic nature of N. We discuss\nthe corresponding uncertainty principle and construct the corresponding\ncoherent states, that may be interpreted as non-commutative solitons."
    },
    {
        "anchor": "Efficient glueball simulations on anisotropic lattices: Monte Carlo results for the low-lying glueball spectrum using an improved,\nanisotropic action are presented. Ten simulations at lattice spacings ranging\nfrom 0.2 to 0.4 fm and two different anisotropies have been performed in order\ndemonstrate the advantages of using coarse, anisotropic lattices to calculate\nglueball masses. Our determinations of the tensor (2++) and pseudovector (1+-)\nglueball masses are more accurate than previous Wilson action calculations.",
        "positive": "Heat Bath Efficiency with Metropolis-Type Updating: We illustrate for 4D SU(2) and U(1) lattice gauge theory that sampling with a\nbiased Metropolis scheme is essentially equivalent to using the heat bath\nalgorithm. Only, the biased Metropolis method can also be applied when an\nefficient heat bath algorithm does not exist."
    },
    {
        "anchor": "Phase structure of pure SU(3) lattice gauge theory in 5 dimensions: We investigate the nonperturbative phase structure of five-dimensional SU(3)\npure Yang-Mills theory on the lattice. We perform numerical simulations using\nthe Wilson plaquette gauge action on an anisotropic lattice with a\nfour-dimensional lattice spacing (a4) and with an independent value in the\nfifth dimension (a5). We investigate both cases of a4 > a5 and a4 < a5. The\nPolyakov loops in the fourth and the fifth directions are observed, and we find\nthat there are four possible phases for the anisotropic five-dimensional\nquenched QCD theory on the lattice. We determine the critical values of the\nlattice bare coupling and the anisotropy parameter for each phase transition.\nFurthermore, we find that the two center domains where the Polyakov loop have\nlocally different charges of the center symmetry appears in single\nconfiguration in the specific region of the lattice parameters.",
        "positive": "Scattering in the pion-nucleon negative parity channel in lattice QCD: We study the coupled pion-nucleon system (negative parity, isospin 1/2) based\non a lattice QCD simulation for nf=2 mass degenerate light quarks. Both,\nstandard 3-quarks baryon operators as well as meson-baryon (4+1)-quark\noperators are included. This is an exploratory study for just one lattice size\nand lattice spacing and at a pion mass of 266 MeV. Using the distillation\nmethod and variational analysis we determine energy levels of the lowest\neigenstates. Comparison with the results of simple 3-quark correlation studies\nexhibits drastic differences and a new level appears. A clearer picture of the\nnegative parity nucleon spectrum emerges. For the parameters of the simulation\nwe may assume elastic s-wave scattering and can derive values of the phase\nshift."
    },
    {
        "anchor": "Confining Classical Configurations: We construct a family of smooth, almost self-dual, non-thermalized SU(2)\ngauge field configurations, and measure the average of the fundamental, adjoint\nand spin $\\frac{3}{2}$ representation Wilson loops on them. We get area law in\nall three cases. We also study thermalised configurations at $\\beta= 2.325$\nafter cooling. The ratio of string tension in the spin j representation over\nthat in the fundamental, stays constant with cooling.",
        "positive": "Topological susceptibility and the sampling of field space in $N_f=2$\n  lattice QCD simulations: We present a measurement of the topological susceptibility in two flavor QCD.\nIn this observable, large autocorrelations are present and also sizable cutoff\neffects have to be faced in the continuum extrapolation. Within the statistical\naccuracy of the computation, the result agrees with the expectation from\nleading order chiral perturbation theory."
    },
    {
        "anchor": "QCD phase diagram in a magnetic background for different values of the\n  pion mass: We investigate the behavior of the pseudo-critical temperature of $N_f = 2+1$\nQCD as a function of a static magnetic background field for different values of\nthe pion mass, going up to $m_\\pi \\simeq 660$ MeV. The study is performed by\nlattice QCD simulations, adopting a stout staggered discretization of the\ntheory on lattices with $N_t = 6$ slices in the Euclidean temporal direction;\nfor each value of the pion mass the temperature is changed moving along a line\nof constant physics. We find that the decrease of $T_c$ as a function of $B$,\nwhich is observed for physical quark masses, persists in the whole explored\nmass range, even if the relative variation of $T_c$ appears to be a decreasing\nfunction of $m_\\pi$, approaching zero in the quenched limit. The location of\n$T_c$ is based on the renormalized quark condensate and its susceptibility;\ndeterminations based on the Polyakov loop lead to compatible results. On the\ncontrary, inverse magnetic catalysis, i.e. the decrease of the quark condensate\nas a function of $B$ in some temperature range around $T_c$, is not observed\nwhen the pion mass is high enough. That supports the idea that inverse magnetic\ncatalysis might be a secondary phenomenon, while the modifications induced by\nthe magnetic background on the gauge field distribution and on the confining\nproperties of the medium could play a primary role in the whole range of pion\nmasses",
        "positive": "Lattice QCD on PCs?: Current PC processors are equipped with vector processing units and have\nother advanced features that can be used to accelerate lattice QCD programs.\nClusters of PCs with a high-bandwidth network thus become powerful and\ncost-effective machines for numerical simulations."
    },
    {
        "anchor": "The excited hadron spectrum in lattice QCD using a new method of\n  estimating quark propagation: Progress in determining the spectrum of excited baryons and mesons in lattice\nQCD is described. Large sets of carefully-designed hadron operators have been\nstudied and their effectiveness in facilitating the extraction of excited-state\nenergies is demonstrated. A new method of stochastically estimating the\nlow-lying effects of quark propagation is proposed which will allow reliable\ndeterminations of temporal correlations of single-hadron and multi-hadron\noperators.",
        "positive": "Joint Contour Net analysis of lattice QCD data: Lattice Quantum Chromodynamics (QCD) is an approach used by theoretical\nphysicists to model the strong nuclear force. This works at the sub-nuclear\nscale to bind quarks together into hadrons including the proton and neutron.\nOne of the long term goals in lattice QCD is to produce a phase diagram of QCD\nmatter as thermodynamic control parameters temperature and baryon chemical\npotential are varied. The ability to predict critical points in the phase\ndiagram, known as phase transitions, is one of the on-going challenges faced by\ndomain scientists. In this work we consider how multivariate topological\nvisualisation techniques can be applied to simulation data to help domain\nscientists predict the location of phase transitions. In the process it is\nintended that applying these techniques to lattice QCD will strengthen the\ninterpretation of output from multivariate topological algorithms, including\nthe joint contour net. Lattice QCD presents an interesting opportunity for\nusing these techniques as it offers a rich array of interacting scalar fields\nfor analysis; however, it also presents unique challenges due to its reliance\non quantum mechanics to interpret the data."
    },
    {
        "anchor": "Ghost-gluon coupling, power corrections and $\u039b_{\\bar{\\rm MS}}$\n  from lattice QCD with a dynamical charm: This paper is a first report on the determination of $\\Lambda_{\\msbar}$ from\nlattice simulations with 2+1+1 twisted-mass dynamical flavours {\\it via} the\ncomputation of the ghost-gluon coupling renormalized in the MOM Taylor scheme.\nWe show this approach allows a very good control of the lattice artefacts and\nconfirm the picture from previous works with quenched and ${\\rm N}_f$=2\ntwisted-mass field configurations which prove the necessity to include\nnon-perturbative power corrections in the description of the running. We\nprovide with an estimate of $\\Lambda_{\\msbar}$ in very good agreement with\nexperimental results. To our knowledge it is the first calculation with a\ndynamical charm quark which makes the running up to $\\alpha_s(M_Z)$ much safer.",
        "positive": "Excited Baryon Spectroscopy from Lattice QCD: Finite Size Effect and\n  Hyperfine Mass Splitting: A study of the finite-size effect is carried out for spectra of both\nground-state and excited-state baryons in quenched lattice QCD using Wilson\nfermions. Our simulations are performed at beta=6.2 with three different\nspatial sizes, La~1.6, 2.2 and 3.2 fm. It is found that the physical lattice\nsize larger than 3 fm is required for delta states in all spin-parity\n(J^{P}=1/2^{+/-}, 3/2^{+/-}) channels and also negative-parity nucleon state\n(J^{P}=1/2^{-}) even in the rather heavy quark mass region. We also find a\npeculiar behavior of the finite-size effect on the hyperfine mass splittings\nbetween the nucleon and the delta in both parity channels."
    },
    {
        "anchor": "$\u039b_b \\to \u039b\\ell^+ \\ell^-$ form factors, differential\n  branching fraction, and angular observables from lattice QCD with\n  relativistic $b$ quarks: Using $(2+1)$-flavor lattice QCD, we compute the 10 form factors describing\nthe $\\Lambda_b \\to \\Lambda$ matrix elements of the $b \\to s$ vector, axial\nvector, and tensor currents. The calculation is based on gauge field ensembles\ngenerated by the RBC and UKQCD Collaborations with a domain-wall action for the\n$u$, $d$, and $s$ quarks and the Iwasaki gauge action. The $b$ quark is\nimplemented using an anisotropic clover action, tuned nonperturbatively to the\nphysical point, and the currents are renormalized with a mostly nonperturbative\nmethod. We perform simultaneous chiral, continuum, and kinematic extrapolations\nof the form factors through modified $z$ expansions. Using our form factor\nresults, we obtain precise predictions for the $\\Lambda_b \\to \\Lambda(\\to p^+\n\\pi^-) \\mu^+ \\mu^-$ differential branching fraction and angular observables in\nthe Standard Model.",
        "positive": "The endpoint of the first-order phase transition of the SU(2)\n  gauge-Higgs model on a 4-dimensional isotropic lattice: We study the first-order finite-temperature electroweak phase transition of\nthe SU(2) gauge-Higgs model defined on a 4-dimensional isotropic lattice with\ntemporal extension N_t=2. Finite-size scaling study of Lee-Yang zeros yields\nthe value of the Higgs self coupling of the endpoint at lambda_c=0.00116(16).\nAn independent analysis of Binder cumulant gives a consistent value for the\nendpoint. Combined with our zero-temperature measurement of Higgs and W boson\nmasses, this leads to M_{H,c}=73.3 +- 6.4 GeV for the critical Higgs boson mass\nbeyond which the electroweak transition turns into a crossover."
    },
    {
        "anchor": "Overlap Quark Propagator in Landau Gauge: The properties of the quark propagator in Landau gauge in quenched QCD are\nexamined for the overlap quark action. The overlap quark action satisfies the\nGinsparg-Wilson relation and as such provides an exact lattice realization of\nchiral symmetry. This in turn implies that the quark action is free of ${\\cal\nO}(a)$ errors. We present results using the standard Wilson fermion kernel in\nthe overlap formalism on a $12^3\\times 24$ lattice at a spacing of 0.125 fm. We\nobtain the nonperturbative momentum-dependent wavefunction renormalization\nfunction $Z(p)$ and the nonperturbative mass function $M(p)$ for a variety of\nbare masses. We perform a simple extrapolation to the chiral limit for these\nfunctions. We clearly observe the dynamically generated infrared mass and\nconfirm the qualitative behavior found for the Landau gauge quark propagator in\nearlier studies. We attempt to extract the quark condensate from the asymptotic\nbehavior of the mass function in the chiral limit.",
        "positive": "The H dibaryon on the lattice: We present our final results for the mass of the six quark flavor singlet\nstate (J^P=0^+, S=-2) called H dibaryon, which would be the lightest possible\nstrangelet in the context of strange quark matter. The calculations are\nperformed in quenched QCD on (8-24)^3 x 30 lattices with the (1,2) Symanzik\nimproved gauge action and the clover fermion action. Furthermore the fuzzing\ntechnique for the fermion fields and smearing of the gauge fields is applied in\norder to enhance the overlap with the ground state. Depending on the lattice\nsize we observe an H mass slightly above or comparable with the \\Lambda\\Lambda\nthreshold for strong decay. Therefore a bound H dibaryon state seemed to be\nruled out by our simulation."
    },
    {
        "anchor": "Phase diagram of Yang-Mills theories in the presence of a theta term: We study the phase diagram of non-Abelian pure gauge theories in the presence\nof a topological theta term. The dependence of the deconfinement temperature on\ntheta is determined on the lattice both by analytic continuation and by\nreweighting, obtaining consistent results. The general structure of the diagram\nis discussed on the basis of large-N considerations and of the possible\nanalogies and dualities existing with the phase diagram of QCD in presence of\nan imaginary baryon chemical potential.",
        "positive": "The quark-mass dependence of elastic $\u03c0K$ scattering from QCD: We present a determination of the isospin-1/2 elastic $\\pi K$ scattering\namplitudes in S and P partial waves using lattice Quantum Chromodynamics. The\namplitudes, constrained for a large number of real-valued energy points, are\nobtained as a function of light-quark mass, corresponding to four pion masses\nbetween 200 and 400 MeV. Below the first inelastic threshold, the P-wave\nscattering amplitude is dominated by a single pole singularity that evolves\nfrom being a stable bound-state at the highest quark mass into a narrow\nresonance that broadens as the pion and kaon masses are reduced. As in\nexperiment, the S-wave amplitude does not exhibit an obviously resonant\nbehavior, but instead shows a slow rise from threshold, which is not\ninconsistent with the presence of a $\\kappa$/$K_0^\\star(700)$-like resonance at\nthe considered quark masses. As has been found in analyses of experimental\nscattering data, simple analytic continuations into the complex energy plane of\nprecisely-determined lattice QCD amplitudes on the real energy axis are not\nsufficient to model-independently determine the existence and properties of\nthis state. The spectra and amplitudes we present will serve as an input for\nincreasingly elaborate amplitude analysis techniques that implement more of the\nanalytic structure expected at complex energies."
    },
    {
        "anchor": "Propagators in lattice Coulomb gauge and confinement mechanisms: We discuss the gluon propagator in 3- and 4-dimensional Yang-Mills theories\nin Coulomb gauge and compare it with the corresponding Landau gauge propagator,\nshowing that for both the relevant IR mass scale coincides. We also report\npreliminary results on Coulomb gauge ghost form factor and quark propagators\nand give a comment on the gluon propagator's strong coupling limit.",
        "positive": "Two dimensional fermions in four dimensional YM: Dirac fermions in the fundamental representation of SU(N) live on a two\ndimensional torus flatly embedded in $R^4$. They interact with a four\ndimensional SU(N) Yang Mills vector potential preserving a global chiral\nsymmetry at finite $N$. As the size of the torus in units of\n$\\frac{1}{\\Lambda_{SU(N)}}$ is varied from small to large, the chiral symmetry\ngets spontaneously broken in the infinite $N$ limit."
    },
    {
        "anchor": "Instantons and Chiral Symmetry on the Lattice: I address the question of how much of QCD in the chiral limit is reproduced\nby instantons. After reconstructing the instanton content of smoothed Monte\nCarlo lattice configurations, I compare hadron spectroscopy on this instanton\nensemble to the spectroscopy on the original ``physical'' smoothed\nconfigurations using a chirally optimised clover fermion action. By studying\nthe zero mode zone in simple instances I find that the optimised action gives a\nsatisfactory description of it. Through the Banks-Casher formula, instantons by\nthemselves are shown to break chiral symmetry but hadron correlators on the\ninstanton backgrounds are strongly influenced by free quark propagation. This\nresults in unnaturally light hadrons and a small splitting between the vector\nand the pseudoscalar meson channels. Superimposing a perturbative ensemble of\nzero momentum gauge field fluctuations (torons) on the instantons is found to\nbe enough to eliminate the free quarks and restore the physical hadron\ncorrelators. I argue that the torons that are present only in finite volumes,\nare probably needed to compensate the unnaturally large finite size effects due\nto the lack of confinement in the instanton ensemble.",
        "positive": "Lattice quark propagator with staggered quarks in Landau and Laplacian\n  gauges: We report on the lattice quark propagator using standard and improved\nStaggered quark actions, with the standard, Wilson gauge action. The standard\nKogut-Susskind action has errors of \\oa{2} while the ``Asqtad'' action has\n\\oa{4}, \\oag{2}{2} errors. The quark propagator is interesting for studying the\nphenomenon of dynamical chiral symmetry breaking and as a test-bed for\nimprovement. Gauge dependent quantities from lattice simulations may be\naffected by Gribov copies. We explore this by studying the quark propagator in\nboth Landau and Laplacian gauges. Landau and Laplacian gauges are found to\nproduce very similar results for the quark propagator."
    },
    {
        "anchor": "Nucleon-nucleon interactions via Lattice QCD: Methodology --HAL QCD\n  approach to extract hadronic interactions in lattice QCD--: We review the potential method in lattice QCD, which has recently been\nproposed to extract nucleon-nucleon interactions via numerical simulations. We\nfocus on the methodology of this approach by emphasizing the strategy of the\npotential method, the theoretical foundation behind it, and special numerical\ntechniques. We compare the potential method with the standard finite volume\nmethod in lattice QCD, in order to make pros and cons of the approach clear. We\nalso present several numerical results for the nucleon-nucleon potentials.",
        "positive": "A perturbative study of two four-quark operators in finite volume\n  renormalization schemes: Starting from the QCD Schroedinger functional (SF), we define a family of\nrenormalization schemes for two four-quark operators, which are, in the chiral\nlimit, protected against mixing with other operators. With the appropriate\nflavour assignments these operators can be interpreted as part of either the\n$\\Delta F=1$ or $\\Delta F=2$ effective weak Hamiltonians. In view of lattice\nQCD with Wilson-type quarks, we focus on the parity odd components of the\noperators, since these are multiplicatively renormalized both on the lattice\nand in continuum schemes. We consider 9 different SF schemes and relate them to\ncommonly used continuum schemes at one-loop order of perturbation theory. In\nthis way the two-loop anomalous dimensions in the SF schemes can be inferred.\nAs a by-product of our calculation we also obtain the one-loop cutoff effects\nin the step-scaling functions of the respective renormalization constants, for\nboth O(a) improved and unimproved Wilson quarks. Our results will be needed in\na separate study of the non-perturbative scale evolution of these operators."
    },
    {
        "anchor": "Continuum Study of Heavy Quark Diffusion: We report on a lattice investigation of heavy quark momentum diffusion within\nthe pure SU(3) plasma above the deconfinement transition with the quarks\ntreated to leading order in the heavy mass expansion. We measure the relevant\n\"colour-electric\" Euclidean correlator and based on several lattice spacing's\nperform the continuum extrapolation. This is necessary not only to remove\ncut-off effects but also the analytic continuation for the extraction of\ntransport coefficients is well-defined only when a continuous function of the\nEuclidean time variable is available. We pay specific attention to scale\nsetting in SU(3). In particular we present our determination for the critical\ntemperature $T_c=1/({N_\\tau}a) $ at values of $N_\\tau \\le 22$.",
        "positive": "Melting Instantons, Domain Walls, and Large N: Monte Carlo studies of $CP^{N-1}$ sigma models have shown that the structure\nof topological charge in these models undergoes a sharp transition at\n$N=N_c\\approx 4$. For $N<N_c$ topological charge is dominated by small\ninstantons, while for $N>N_c$ it is dominated by extended, thin,\n1-dimensionally coherent membranes of topological charge, which can be\ninterpreted as domain walls between discrete quasi-stable vacua. These vacua\ndiffer by a unit of background electric flux. The transition can be identified\nas the delocalization of topological charge, or \"instanton melting,\" a\nphenomenon first suggested by Witten to resolve the conflict between instantons\nand large $N$ behavior. Implications for $QCD$ are discussed."
    },
    {
        "anchor": "WW Scattering Parameters via Pseudoscalar Phase Shifts: Using domain-wall lattice simulations, we study pseudoscalar-pseudoscalar\nscattering in the maximal isospin channel for an SU(3) gauge theory with two\nand six fermion flavors in the fundamental representation. This calculation of\nthe S-wave scattering length is related to the next-to-leading order\ncorrections to WW scattering through the low-energy coefficients of the chiral\nLagrangian. While two and six flavor scattering lengths are similar for a fixed\nratio of the pseudoscalar mass to its decay constant, six-flavor scattering\nshows a somewhat less repulsive next-to-leading order interaction than its\ntwo-flavor counterpart. Estimates are made for the WW scattering parameters and\nthe plausibility of detection is discussed.",
        "positive": "A no-go theorem for the Majorana fermion on a lattice: A variant of the Nielsen--Ninomiya no-go theorem is formulated. This theorem\nstates that, under several assumptions, it is impossible to write down a\ndoubler-free Euclidean lattice action of a single Majorana fermion in $8k$ and\n$8k+1$ dimensions."
    },
    {
        "anchor": "Improved results for the mass spectrum of N=1 supersymmetric SU(3)\n  Yang-Mills theory: This talk summarizes the results of the DESY-M\\\"unster collaboration for\n$\\mathcal{N}=1$ supersymmetric Yang-Mills theory with the gauge group SU(3). It\nis an updated status report with respect to our preliminary data presented at\nthe last conference. In order to control the lattice artefacts we have now\nconsidered a clover improved fermion action and different values of the gauge\ncoupling.",
        "positive": "Future Perspectives in Lattice Field Theory: I review some of the contributions which lattice simulations are likely to\nmake during the next five years or so to the development of our understanding\nof particle physics. Particular emphasis is given to the evaluation of\nnon-perturbative QCD effects in experimentally measurable amplitudes, and the\ncorresponding extraction of fundamental parameters."
    },
    {
        "anchor": "Glueball Regge Trajectories: We investigate the spectrum of glueballs in 3D and 4D SU(N) gauge theories.\nOur motivation is to determine whether the states lie on straight Regge\ntrajectories. To this end we develop new lattice techniques to reliably\ndetermine the states carrying higher spin. It has been conjectured for a long\ntime that glueballs are the physical states lying on the pomeron, the\ntrajectory responsible for the slowly rising hadronic cross-sections at large\ncentre-of-mass energy.",
        "positive": "Non-perturbative renormalization by decoupling: We propose a new strategy for the determination of the QCD coupling. It\nrelies on a coupling computed in QCD with $N_{\\rm f} \\geq 3$ degenerate heavy\nquarks at a low energy scale $\\mu_{\\rm dec}$, together with a non-perturbative\ndetermination of the ratio $\\Lambda/\\mu_{\\rm dec}$ in the pure gauge theory. We\nexplore this idea using a finite volume renormalization scheme for the case of\n$N_{\\rm f} = 3$ QCD, demonstrating that a precise value of the strong coupling\n$\\alpha_s$ can be obtained. The idea is quite general and can be applied to\nsolve other renormalization problems, using finite or infinite volume\nintermediate renormalization schemes."
    },
    {
        "anchor": "Lattice Supersymmetry via Twisting: We describe how the usual supercharges of extended supersymmetry may be {\\it\ntwisted} to produce a BRST-like supercharge $Q$. The usual supersymmetry\nalgebra is then replaced by a twisted algebra and the action of the twisted\ntheory is shown to be generically $Q$-exact. In flat space the twisting\nprocedure can be regarded as a change of variables carrying no physical\nsignificance. However, the twisted theories can often be transferred to the\nlattice while preserving the twisted supersymmetry. As an example we construct\na lattice version of the two-dimensional supersymmetric sigma model.",
        "positive": "A multilevel algorithm for flow observables in gauge theories: We study the possibility of using multilevel algorithms for the computation\nof correlation functions of gradient flow observables. For each point in the\ncorrelation function an approximate flow is defined which depends only on links\nin a subset of the lattice. Together with a local action this allows for\nindependent updates and consequently a convergence of the Monte Carlo process\nfaster than the inverse square root of the number of measurements. We\ndemonstrate the feasibility of this idea in the correlation functions of the\ntopological charge and the energy density."
    },
    {
        "anchor": "Lattice Landau gauge with stochastic quantisation: We calculate Landau gauge ghost and gluon propagators in pure SU(2) lattice\ngauge theory in two, three and four dimensions. The gauge fixing method we use,\nsc. stochastic quantisation, serves as a viable alternative approach to\nstandard gauge fixing algorithms. We also investigate the spectrum of the\nFaddeev-Popov operator. At insufficiently accurate gauge fixing, we find\nevidence that stochastic quantisation samples configurations close to the\nGribov horizon. Standard gauge fixing does so only at specific parameters;\notherwise, there is a clear difference. However, this difference disappears if\nthe gauge is fixed to sufficient accuracy. In this case, we confirm previous\nlattice results for the gluon and ghost propagator in two, three and four\ndimensions.",
        "positive": "Determination of the properties of vector mesons in external magnetic\n  field by Quenched $SU(3)$ Lattice QCD: We investigate the ground state energies of vector $\\rho^{\\pm}$ and $K^{\\pm\n*}$ mesons depending on the magnetic field value in the $SU(3)$ lattice gauge\ntheory. It has been shown that the energy of a vector particle depends on its\nspin projection on the field axis. The magnetic dipole polarizability and\nhyperpolarizabilities give significant contributions to the energy value which\nprevents the formation of the charged vector meson condensate at high magnetic\nfields. We calculate the g-factor of $\\rho^{\\pm}$ and $K^{\\pm*}$ mesons and the\ndipole magnetic polarizability of $\\rho^{\\pm}$ mesons."
    },
    {
        "anchor": "The Compton Amplitude, lattice QCD and the Feynman-Hellmann approach: A major objective of lattice QCD is the computation of hadronic matrix\nelements. The standard method is to use three-point and four-point correlation\nfunctions. An alternative approach, requiring only the computation of two-point\ncorrelation functions is to use the Feynman-Hellmann theorem. In this talk we\ndevelop this method up to second order in perturbation theory, in a context\nappropriate for lattice QCD. This encompasses the Compton Amplitude (which\nforms the basis for deep inelastic scattering) and hadron scattering. Some\nnumerical results are presented showing results indicating what this approach\nmight achieve.",
        "positive": "Excited states of massive fermions in a chiral gauge theory: It is shown numerically, in a chiral U(1) gauge Higgs theory in which the\nleft and right-handed fermion components have opposite U(1) charges, that the\nspectrum of gauge and Higgs fields surrounding a static fermion contains both a\nground state and at least one stable excited state. To bypass the difficulties\nassociated with dynamical fermions in a lattice chiral gauge theory we consider\nonly static fermion sources in a quenched approximation, at fixed lattice\nspacing and couplings, and with a lattice action along the lines suggested long\nago by Smit and Swift."
    },
    {
        "anchor": "Fixed-scale approach to finite-temperature lattice QCD with shifted\n  boundaries: We study the thermodynamics of the SU(3) gauge theory using the fixed-scale\napproach with shifted boundary conditions. The fixed-scale approach can reduce\nthe numerical cost of the zero-temperature part in the equation of state\ncalculations, while the number of possible temperatures is limited by the\ninteger $N_t$, which represents the temporal lattice extent. The shifted\nboundary conditions can overcome such a limitation while retaining the\nadvantages of the fixed-scale approach. Therefore, our approach enables the\ninvestigation of not only the equation of state in detail, but also the\ncalculation of the critical temperature with increased precision even with the\nfixed-scale approach. We also confirm numerically that the boundary conditions\nsuppress the lattice artifact of the equation of state, which has been\nconfirmed in the non-interacting limit.",
        "positive": "Hadron Spectroscopy: Recent results on the hadron spectroscopy from lattice QCD are reviewed with\nemphasis on the meson sector and in particular on quarkonium-like $XYZ$ states.\nI report on the first rigorous treatment of the near-threshold states $X(3872)$\nand $D_s^0(2317)$, and the lattice searches for $Z_c^+(3900)$, $X(4140)$ and\ndouble-charm tetraquark states. Meson resonances in light, strange and charm\nsector are reviewed, where the resonances masses as well as the strong decay\nwidths are reported. The first lattice QCD simulation of two coupled-channels\nis discussed."
    },
    {
        "anchor": "Iterative methods for overlap and twisted mass fermions: We present a comparison of a number of iterative solvers of linear systems of\nequations for obtaining the fermion propagator in lattice QCD. In particular,\nwe consider chirally invariant overlap and chirally improved Wilson (maximally)\ntwisted mass fermions. The comparison of both formulations of lattice QCD is\nperformed at four fixed values of the pion mass between 230MeV and 720MeV. For\noverlap fermions we address adaptive precision and low mode preconditioning\nwhile for twisted mass fermions we discuss even/odd preconditioning. Taking the\nbest available algorithms in each case we find that calculations with the\noverlap operator are by a factor of 30-120 more expensive than with the twisted\nmass operator.",
        "positive": "Antiferromagnetic 4-d O(4) Model: We study the phase diagram of the four dimensional O(4) model with first\n(beta1) and second (beta2) neighbor couplings, specially in the beta2 < 0\nregion, where we find a line of transitions which seems to be second order. We\nalso compute the critical exponents on this line at the point beta1 =0 (F4\nlattice) by Finite Size Scaling techniques up to a lattice size of 24, being\nthese exponents different from the Mean Field ones."
    },
    {
        "anchor": "Glueballs, strings and topology in SU(N) gauge theory: I show how one can use lattice methods to calculate various continuum\nproperties of SU(N) gauge theories; in part to explore old ideas that N=3 might\nbe close to N=infinity. I describe calculations of the low-lying `glueball'\nmass spectrum, of the string tensions of k-strings and of topological\nfluctuations for N=2,3,4,5. We find that mass ratios appear to show a rapid\napproach to the large-N limit, and, indeed, can be described all the way down\nto SU(2) using just a leading O(1/NxN) correction. We confirm that the smooth\nlarge-N limit we find is confining and is obtained by keeping a constant 't\nHooft coupling. We find that the ratio of the k=2 string tension to the k=1\nfundamental string tension is much less than the naive (unbound) value of 2 and\nis considerably greater than the naive bag model prediction; in fact we find\nthat it is consistent, within quite small errors, with either the\nM(-theory)QCD-inspired conjecture or with `Casimir scaling'. Finally I describe\ncalculations of the topological charge of the gauge fields. We observe that, as\nexpected, the density of small-size instantons vanishes rapidly as N increases,\nwhile the topological susceptibility appears to have a non-zero N=infinity\nlimit.",
        "positive": "Applying Groebner Bases to Solve Reduction Problems for Feynman\n  Integrals: We describe how Groebner bases can be used to solve the reduction problem for\nFeynman integrals, i.e. to construct an algorithm that provides the possibility\nto express a Feynman integral of a given family as a linear combination of some\nmaster integrals. Our approach is based on a generalized Buchberger algorithm\nfor constructing Groebner-type bases associated with polynomials of shift\noperators. We illustrate it through various examples of reduction problems for\nfamilies of one- and two-loop Feynman integrals. We also solve the reduction\nproblem for a family of integrals contributing to the three-loop static quark\npotential."
    },
    {
        "anchor": "Quark masses and the chiral condensate with a non-perturbative\n  renormalization procedure: We determine the quark masses and the chiral condensate in the MSbar scheme\nat NNLO from Lattice QCD in the quenched approximation at beta=6.0, beta=6.2\nand beta=6.4 using both the Wilson and the tree-level improved SW-Clover\nfermion action. We extract these quantities using the Vector and the Axial Ward\nIdentities and non-perturbative values of the renormalization constants. We\ncompare the results obtained with the two methods and we study the O(a)\ndependence of the quark masses for both actions.",
        "positive": "Twelve massless flavors and three colors below the conformal window: We report new results for a frequently discussed gauge theory with twelve\nfermion flavors in the fundamental representation of the SU(3) color gauge\ngroup. The model, controversial with respect to its conformality, is important\nin non-perturbative studies searching for a viable composite Higgs mechanism\nBeyond the Standard Model (BSM). To resolve the controversy, we subject the\nmodel to opposite hypotheses inside and outside of the conformal window. In the\nfirst hypothesis we test chiral symmetry breaking ($\\chi{\\rm SB}$) with its\nGoldstone spectrum, $F_\\pi$, the $\\chi{\\rm SB}$ condensate, and several\ncomposite hadron states as the fermion mass is varied in a limited range with\nour best effort to control finite volume effects and extrapolation to the\nmassless chiral limit. Supporting results for $\\chi{\\rm SB}$ from the running\ncoupling based on the force between static sources and some preliminary\nevidence for the finite temperature transition are also presented. In the\nsecond test for the alternate hypothesis we probe conformal behavior driven by\na single anomalous mass dimension under the assumption of unbroken chiral\nsymmetry. Our results show a very low level of confidence in the conformal\nscenario. Staggered lattice fermions with stout-suppressed taste breaking are\nused throughout the simulations."
    },
    {
        "anchor": "Magnetic Catalysis in Graphene Effective Field Theory: We report on the first observation of magnetic catalysis at zero temperature\nin a fully nonperturbative simulation of the graphene effective field theory.\nUsing lattice gauge theory, a nonperturbative analysis of the theory of\nstrongly-interacting, massless, (2+1)-dimensional Dirac fermions in the\npresence of an external magnetic field is performed. We show that in the\nzero-temperature limit, a nonzero value for the chiral condensate is obtained\nwhich signals the spontaneous breaking of chiral symmetry. This result implies\na nonzero value for the dynamical mass of the Dirac quasiparticle. This in turn\nhas been posited to account for the quantum-Hall plateaus that are observed at\nlarge magnetic fields.",
        "positive": "Detecting critical points from Lee-Yang edge singularities in lattice\n  QCD: A new approach is presented to explore the singularity structure of lattice\nQCD in the complex chemical potential plane. Our method can be seen as a\ncombination of the Taylor expansion and analytic continuation approaches. Its\nnovelty lies in using rational (Pad\\'e) approximants for studying Lee-Yang edge\nsingularities. We present a calculation of the cumulants of the net-baryon\nnumber as a function of a purely imaginary baryon number chemical potential,\nobtained with highly improved staggered quarks at temporal lattice extent of\n$N_\\tau=4,6$. We construct various rational function approximations of the\nlattice data and determine their poles (and roots) in the complex plane. We\ncompare the position of the closest pole to the theoretically expected position\nof the Lee-Yang edge singularity. At high temperature, we find scaling that is\nin accordance with the expected power law behavior of the Roberge-Weiss\ntransition while a different behavior is found for $T\\lesssim 170$ MeV."
    },
    {
        "anchor": "Playing with the kinetic term in the HMC: The HMC algorithm, combining the advantages of molecular dynamics and\nMonte-Carlo methods, is the most efficient algorithm to simulate QCD including\nthe effects of sea quarks. In the standard approach momentum fields are\ngenerated with a Gaussian probability density. In this work I will explore\nanother possibility. By using a Lorentz distribution one can dynamically impose\na cutoff in the rate of change of the coordinates that potentially could have a\nbetter behavior. I will present some results in pure SU(2) gauge theory.",
        "positive": "Lowest-lying Tetra-Quark Hadrons in Anisotropic Lattice QCD: We present a detailed study of lowest-lying $q^{2}\\bar{q}^{2}$ hadrons in\nquenched improved anisotropic lattice QCD. Using the $\\pi\\pi$ and\ndiquark-antidiquark local and smeared operators, we attempt to isolate the\nsignal for $I(J^{P})=0(0^{+}), 2(0^{+})$ and $1(1^{+})$ states in two flavour\nQCD. In the chiral limit of light-quark mass region, the lowest scalar $4q$\nstate is found to have a mass, $m^{I=0}_{4q}=927(12)$ MeV, which is slightly\nlower than the experimentally observed $f_{0}(980)$. The results from our\nvariational analysis do not indicate a signature of a tetraquark resonance in\nI=1 and I=2 channels. After the chiral extrapolation the lowest $1(1^{+})$\nstate is found to have a mass, $m^{I=1}_{4q}=1358(28)$ MeV. We analysed the\nstatic $4q$ potential extracted form a tetraquark Wilson loop and illustrated\nthe behaviour of the $4q$ state as a bound state, unbinding at some critical\ndiquark separation. From our analysis we conclude that scalar $4q$ system\nappears as a two-pion scattering state and that there is no spatially-localised\n$4q$ state in the light-quark mass region."
    },
    {
        "anchor": "Extraction of lattice QCD spectral densities from an ensemble of trained\n  machines: In this talk we discuss a novel method, that we have presented in Ref. [1],\nto extract hadronic spectral densities from lattice correlators by using deep\nlearning techniques. Hadronic spectral densities play a crucial role in the\nstudy of the phenomenology of strong-interacting particles and the problem of\ntheir extraction from Euclidean lattice correlators has already been approached\nin the literature by using machine learning techniques. A distinctive feature\nof our method is a model-independent training strategy that we implement by\nparametrizing the training sets over a functional space spanned by Chebyshev\npolynomials. The other distinctive feature is a reliable estimate of the\nsystematic uncertainties that we obtain by introducing an ensemble of machines\nin order to study numerically the asymptotic limits of infinitely large\nnetworks and training sets. The method is validated on a very large set of\nrandom mock data and also in the case of lattice QCD data.",
        "positive": "More chiral operators on the lattice: Instead of the Ginsparg-Wilson (GW) relation we only require generalized\nchiral symmetry and show that this results in a larger class of Dirac operators\ndescribing massless fermions, which in addition to GW fermions and to the ones\nproposed by Fujikawa includes many more general ones. The index turns out to\ndepend solely on a basic unitary operator. We use spectral representations to\nanalyze the new class and to obtain detailed properties. We also show that our\nweaker conditions still lead properly to Weyl fermions and to chiral gauge\ntheories."
    },
    {
        "anchor": "Out-of-equilibrium simulations to fight topological freezing: Calculations of topological observables in lattice gauge theories with\ntraditional Monte Carlo algorithms have long been known to be a difficult task,\nowing to the effects of long autocorrelations times. Several mitigation\nstrategies have been put forward, including the use of open boundary conditions\nand methods such as parallel tempering. In this contribution we examine a new\napproach based on out-of-equilibrium Monte Carlo simulations. Starting from\nthermalized configurations with open boundary conditions on a line defect,\nperiodic boundary conditions are gradually switched on. A sampling of\ntopological observables is then shown to be possible with a specific\nreweighting-like technique inspired by Jarzynski's equality. We discuss the\nefficiency of this approach using results obtained for the 2-dimensional\n$\\mathrm{CP}^{N-1}$ models. Furthermore, we outline the implementation of our\nproposal in the context of Stochastic Normalizing Flows, as they share the same\ntheoretical framework of the non-equilibrium transformations we perform, and\ncan be thought of as their generalization.",
        "positive": "Perturbative Renormalization of quasi-PDFs: In this paper we present results for the renormalization of gauge invariant\nnonlocal fermion operators which contain a Wilson line, to one-loop level in\nlattice perturbation theory. Our calculations have been performed for\nWilson/clover fermions and a wide class of Symanzik improved gluon actions. The\nextended nature of such long-link operators results in a nontrivial\nrenormalization, including contributions which diverge linearly as well as\nlogarithmically with the lattice spacing, along with additional finite factors.\nOn the lattice there is also mixing among certain subsets of these nonlocal\noperators; we calculate the corresponding finite mixing coefficients, which are\nnecessary in order to disentangle individual matrix elements for each operator\nfrom lattice simulation data. Finally, extending our perturbative setup, we\npresent non-perturbative prescriptions to extract the linearly divergent\ncontributions."
    },
    {
        "anchor": "Study of the Higgs-Yukawa theory in the strong-Yukawa coupling regime: In this article, we present an ongoing lattice study of the Higgs-Yukawa\nmodel, in the regime of strong-Yukawa coupling, using overlap fermions. We\ninvestigated the phase structure in this regime by computing the Higgs vacuum\nexpectation value, and by exploring the finite-size scaling behaviour of the\nsusceptibility corresponding to the magnetisation. Our preliminary results\nindicate the existence of a second-order phase transition when the Yukawa\ncoupling becomes large enough, at which the Higgs vacuum expectation value\nvanishes and the susceptibility diverges.",
        "positive": "Possible Color Octet Quark-Anti-Quark Condensate in the Instanton Model: Inspired by a recent proposal for a Higgs description of QCD we study the\npossible formation of a color-octet/flavor-octet quark-anti-quark condensate in\nthe instanton liquid model. For this purpose we calculate two-point correlation\nfunctions of color-singlet and octet quark-anti-quark operators. We find long\nrange order in the standard $<\\bar{\\psi}\\psi>$ channel, but not in the\ncolor-octet channel. We emphasize that similar calculations in lattice QCD can\ncheck whether or not a color-flavor locked Higgs phase is realized in QCD at\nzero temperature and baryon density."
    },
    {
        "anchor": "Energy-momentum tensor from the Yang-Mills gradient flow: The product of gauge fields generated by the Yang-Mills gradient flow for\npositive flow times does not exhibit the coincidence-point singularity and a\nlocal product is thus independent of the regularization. Such a local product\ncan furthermore be expanded by renormalized local operators at zero flow time\nwith finite coefficients that are governed by renormalization group equations.\nUsing these facts, we derive a formula that relates the small flow-time\nbehavior of certain gauge-invariant local products and the correctly-normalized\nconserved energy-momentum tensor in the Yang-Mills theory. Our formula provides\na possible method to compute the correlation functions of a well-defined\nenergy-momentum tensor by using lattice regularization and Monte Carlo\nsimulation.",
        "positive": "New phases of finite temperature gauge theory from an extended action: We study the behavior of the order parameter, the phase diagram, and the\nthermodynamics of exotic phases of finite temperature gauge theory. Lattice\nsimulations were performed in SU(3) and SU(4) with an adjoint Polyakov loop\nterm added to the standard Wilson action. In SU(3), the pattern of Z(3)\nsymmetry breaking in the new phase is distinct from the pattern observed in the\ndeconfined phase. In SU(4), the Z(4) symmetry is spontaneously broken down to\nZ(2), representing a partially-confined phase. The existence of the new phases\nis confirmed in analytical calculations of the free energy based on\nhigh-temperature perturbation theory."
    },
    {
        "anchor": "QCD thermodynamics at zero and finite densities with improved Wilson\n  quarks: The WHOT-QCD Collaboration is pushing forward lattice studies of QCD at\nfinite temperatures and densities using improved Wilson quarks. We first\npresent results on QCD at zero and finite densities with two flavors of\ndegenerate quarks (N_F=2 QCD) adopting the conventional fixed-Nt approach. We\nthen report on the status of a study of N_F=2+1 QCD adopting a fixed-scale\napproach armed with the T-integration method which we have developed.",
        "positive": "Evading the sign problem in random matrix simulations: In this talk we show how the sign problem, occurring in dynamical simulations\nof random matrices at nonzero chemical potential, can be avoided by judiciously\ncombining matrices into subsets. One can prove that these subsets have real and\npositive weights such that importance sampling can be used in Monte Carlo\nsimulations. The number of matrices per subset is proportional to the matrix\ndimension. We measure the chiral condensate and observe that the statistical\nerror is independent of the chemical potential and grows linearly with the\nmatrix dimension, which contrasts strongly with its exponential growth in\nreweighting methods."
    },
    {
        "anchor": "Constraining the QCD phase diagram by tricritical lines at imaginary\n  chemical potential: We present unambiguous evidence from lattice simulations of QCD with three\ndegenerate quark species for two tricritical points in the (T,m) phase diagram\nat fixed imaginary \\mu/T=i\\pi/3 mod 2\\pi/3, one in the light and one in the\nheavy mass regime. These represent the boundaries of the chiral and\ndeconfinement critical lines continued to imaginary chemical potential,\nrespectively. It is demonstrated that the shape of the deconfinement critical\nline for real chemical potentials is dictated by tricritical scaling and\nimplies the weakening of the deconfinement transition with real chemical\npotential. The generalization to non-degenerate and light quark masses is\ndiscussed.",
        "positive": "Phase ambiguity of the measure for continuum Majorana fermions: Integrating over a continuum Majorana fermion formally yields a functional\npfaffian. We show that the phase of this pfaffian is ambiguous, as it depends\non the choice of basis. This ambiguity is naturally resolved within a\nnon-perturbative lattice definition, allowing us to discuss the relation\nbetween the phase of the lattice pfaffian and the effective $\\theta$ angle of\nthe theory. We also resolve an apparent paradox regarding the induced $\\theta$\nangle when a theory of $N$ Dirac fermions in a real representation of the gauge\ngroup is re-expressed in terms of $2N$ Majorana fermions. We discuss how all\nthis is reflected in chiral perturbation theory."
    },
    {
        "anchor": "B-meson decay constants: a more complete picture from full lattice QCD: We extend the picture of $B$-meson decay constants obtained in lattice QCD\nbeyond those of the $B$, $B_s$ and $B_c$ to give the first full lattice QCD\nresults for the $B^*$, $B^*_s$ and $B^*_c$. We use improved NonRelativistic QCD\nfor the valence $b$ quark and the Highly Improved Staggered Quark (HISQ) action\nfor the lighter quarks on gluon field configurations that include the effect of\n$u/d$, $s$ and $c$ quarks in the sea with $u/d$ quark masses going down to\nphysical values. For the ratio of vector to pseudoscalar decay constants, we\nfind $f_{B^*}/f_B$ = 0.941(26), $f_{B^*_s}/f_{B_s}$ = 0.953(23) (both $2\\sigma$\nless than 1.0) and $f_{B^*_c}/f_{B_c}$ = 0.988(27). Taking correlated\nuncertainties into account we see clear indications that the ratio increases as\nthe mass of the lighter quark increases. We compare our results to those using\nthe HISQ formalism for all quarks and find good agreement both on decay\nconstant values when the heaviest quark is a $b$ and on the dependence on the\nmass of the heaviest quark in the region of the $b$. Finally, we give an\noverview plot of decay constants for gold-plated mesons, the most complete\npicture of these hadronic parameters to date.",
        "positive": "Heavy-light hadrons and their excitations: We study the excitations of hadrons containing a single heavy quark. We\npresent meson and baryon mass splittings and ratios of meson decay constants\nresulting from quenched and dynamical two-flavor configurations. Light quarks\nare simulated using the Chirally Improved (CI) lattice Dirac operator. The\nheavy quark is approximated by a static propagator, appropriate for the $b$\nquark on our lattices ($1/a \\sim 1-2$ GeV). We also include some preliminary\ncalculations of the heavy-quark kinetic corrections to the states."
    },
    {
        "anchor": "Pseudo-scalar meson spectral properties in the chiral crossover region\n  of QCD: Determining the type of excitations that can exist in a thermal medium is key\nto understanding how hadronic matter behaves at extreme temperatures. In this\nwork we study this question for pseudo-scalar mesons comprised of light-strange\nand strange-strange quarks, analysing how their low-energy spectral properties\nare modified as one passes through the high-temperature chiral crossover region\nbetween $T=145.6 \\, \\text{MeV}$ and $172.3 \\, \\text{MeV}$. We utilise the\nnon-perturbative constraints satisfied by correlation functions at finite\ntemperature in order to extract the low-energy meson spectral function\ncontributions from spatial correlator lattice data in $N_{f}=2+1$ flavour QCD.\nThe robustness of these contributions are tested by comparing their predictions\nwith data for the corresponding temporal correlator at different momentum\nvalues. We find that around the pseudo-critical temperature $T_{\\text{pc}}$ the\ndata in both the light-strange and strange-strange channels is consistent with\nthe presence of a distinct stable particle-like ground state component, a\nso-called thermoparticle excitation. As the temperature increases this\nexcitation undergoes collisional broadening, and this is qualitatively the same\nin both channels. These findings suggest that pseudo-scalar mesons in QCD have\na bound-state-like structure at low energies within the chiral crossover region\nwhich is still strongly influenced by the vacuum states of the theory.",
        "positive": "Simulating Four-Dimensional Simplicial Gravity using Degenerate\n  Triangulations: We extend a model of four-dimensional simplicial quantum gravity to include\ndegenerate triangulations in addition to combinatorial triangulations\ntraditionally used. Relaxing the constraint that every 4-simplex is uniquely\ndefined by a set of five distinct vertexes, we allow triangulations containing\nmultiply connected simplexes and distinct simplexes defined by the same set of\nvertexes. We demonstrate numerically that including degenerated triangulations\nsubstantially reduces the finite-size effects in the model. In particular, we\nprovide a strong numerical evidence for an exponential bound on the entropic\ngrowth of the ensemble of degenerate triangulations, and show that a\ndiscontinuous crumpling transition is already observed on triangulations of\nvolume N_4 ~= 4000."
    },
    {
        "anchor": "An explicit example of HQET at one-loop order of perturbation theory: As an explicit example of HQET, we construct correlation functions containing\na heavy-light axial current, both in the static approximation and in full QCD.\nThis enables us to investigate the size of finite mass effects. As we use the\nlattice regularisation, we can also check the mass dependence of discretisation\nerrors.",
        "positive": "Tetraquark systems $\\bar bb\\bar du$ in the static limit and lattice QCD: Two hadrons with exotic quark content $Z_b^+\\simeq \\bar bb \\bar du$ were\ndiscovered by Belle. We present a lattice study of the $\\bar bb\\bar du$ systems\nwith various quantum numbers using static bottom quarks. Only one set of\nquantum numbers that couples to $Z_b$ and $\\Upsilon\\;\\pi$ was explored on the\nlattice before; these studies found an attractive potential between $B$ and\n$\\bar B^*$ resulting in a bound state below the threshold. The present study\nconsiders the other three sets of quantum numbers. Eigenenergies of the $\\bar\nbb \\bar du$ system are extracted as a function of separation between $b$ and\n$\\bar b$. The resulting eigenenergies do not show any sizable deviation from\nnoninteracting energies of the systems $\\bar bb+\\bar du$ and $\\bar bu+\\bar db$,\nso no significant attraction or repulsion is found. A slight exception is a\nsmall attraction between $B$ and $\\bar B^*$ at small distance for the quantum\nnumber that couples to $Z_b$ and $\\eta_b\\;\\rho$."
    },
    {
        "anchor": "Monopoles, topology of the Standard Model, and unification of\n  interactions at Tev scale: It is shown that unification of strong and Electroweak interactions at Tev\nscale may lead to appearance of topologically stable monopoles with masses of\nthe order of 40 Tev. Those monopoles may play an important role in the early\nUniverse, at finite temperature. They may even be condensed at high enough\ntemperature. The lattice model for investigation of this phenomenon is\npresented.",
        "positive": "Infrared fixed point in SU(2) gauge theory with adjoint fermions: We apply Schrodinger-functional techniques to the SU(2) lattice gauge theory\nwith N_f=2 flavors of fermions in the adjoint representation. Our use of\nhypercubic smearing enables us to work at stronger couplings than did previous\nstudies, before encountering a critical point and a bulk phase boundary.\nMeasurement of the running coupling constant gives evidence of an infrared\nfixed point g* where 1/g*^2 = 0.20(4)(3). At the fixed point, we find a mass\nanomalous dimension gamma_m(g*) = 0.31(6)."
    },
    {
        "anchor": "Nonperturbative renormalization of staple-shaped Wilson line operators\n  in lattice QCD: Quark bilinear operators with staple-shaped Wilson lines are used to study\ntransverse-momentum-dependent parton distribution functions (TMDPDFs) from\nlattice quantum chromodynamics (QCD). Here, the renormalization factors for the\nisovector operators, including all mixings between operators with different\nDirac structures, are computed nonperturbatively in the\nregularization-independent momentum subtraction scheme for the first time. This\nstudy is undertaken in quenched QCD with three different lattice spacings. With\nWilson flow applied to the gauge fields in the calculations, the operator\nmixing pattern due to chiral symmetry breaking with the lattice regularization\nis found to be significantly different from that predicted by one-loop lattice\nperturbation theory calculations. These results constitute a critical step\ntowards the systematic extraction of TMDPDFs from lattice QCD.",
        "positive": "Lattice Yang-Mills theory at finite densities of heavy quarks: SU(N_c) Yang-Mills theory is investigated at finite densities of N_f heavy\nquark flavors. The calculation of the (continuum) quark determinant in the\nlarge-mass limit is performed by analytic methods and results in an effective\ngluonic action. This action is then subject to a lattice representation of the\ngluon fields and computer simulations. The approach maintains the same number\nof quark degrees of freedom as in the continuum formulation and a physical\nheavy quark limit (to be contrasted with the quenched approximation N_f -> 0).\nThe proper scaling towards the continuum limit is manifest. We study the\npartition function for given values of the chemical potential as well as the\npartition function which is projected onto a definite baryon number. First\nnumerical results for an SU(2) gauge theory are presented. We briefly discuss\nthe breaking of the color-electric string at finite densities and shed light\nonto the origin of the overlap problem inherent in the Glasgow approach."
    },
    {
        "anchor": "New developments for dual methods in lattice field theory at non-zero\n  density: In recent years the complex action problem of lattice field theory at finite\ndensity was overcome for several system by mapping them to dual variables (flux\nlines and surfaces). We illustrate this mapping for the case of the U(1) gauge\nHiggs system and present some representative physics results for this model.\nConceptual challenges such as spectroscopy in the dual approach, as well as\nalgorithmic developments are discussed and related ideas for systems with\nfermions are addressed. Models where the dual variables approach solves the\ncomplex action problem can serve as reference systems for other approaches to\nfinite density lattice field theory and we discuss some examples. Finally we\naddress the strategy of a partial dualization in certain limits, e.g., for\nstrong coupling and large mass.",
        "positive": "Non-perturbative renormalization of tensor bilinears in Schr\u00f6dinger\n  Functional schemes: We present preliminary result for the study of the renormalization group\nevolution of tensor bilinears in Schr\\\"odinger Functional (SF) schemes for\n$N_f=0$ and $N_f=2$ QCD with non-perturbatively $\\mathcal{O}(a)$-improved\nWilson fermions. First $N_f=2+1$ results (proceeding in parallel with the\nongoing computation of the running quark masses [1] are also discussed. A\none-loop perturbative calculation of the discretisation effects for the\nrelevant step scaling functions has been carried out for both Wilson and\n$\\mathcal{O}(a)$-improved actions and for a large number of lattice\nresolutions. We also calculate the two-loop anomalous dimension in SF schemes\nfor tensor currents through a scheme matching procedure with RI and\n$\\overline{\\rm MS}$. Thanks to the SF iterative procedure the non-perturbative\nrunning over two orders of magnitude in energy scales, as well as the\ncorresponding Renormalization Group Invariant operators, have been determined."
    },
    {
        "anchor": "High loop renormalization constants by NSPT: a status report: We present an update on Numerical Stochastic Perturbation Theory projects for\nLattice QCD, which are by now run on apeNEXT. As a first issue, we discuss a\nstrategy to tackle finite size effects which can be quite sizeable in the\ncomputation of logarithmically divergent renormalization constants. Our first\nhigh loop determination of quark bilinears for Wilson fermions was limited to\nfinite constants and finite ratios. A precise determination of Z_P and Z_S (and\nhence of Z_m) now becomes possible. We also give an account of computations for\nactions different from the standard regularization we have taken into account\nso far (Wilson gauge action and Wilson fermions). In particular, we present the\nstatus of computations for the Lattice QCD regularization defined by tree level\nSymanzik improved gauge action and Wilson fermions, which became quite popular\nin recent times. We also take the chance to discuss the related topic of the\ncomputation of the gluon and ghost propagators (which we undertook in\ncollaboration with another group). This is relevant in order to better\nunderstand non-perturbative computations of propagators aiming at\nqualitative/quantitative understanding of confinement.",
        "positive": "On the Quantum Geometry of String Theory: The IKKT or IIB matrix model has been proposed as a non-perturbative\ndefinition of type IIB superstring theories. It has the attractive feature that\nspace--time appears dynamically. It is possible that lower dimensional\nuniverses dominate the theory, therefore providing a dynamical solution to the\nreduction of space--time dimensionality. We summarize recent works that show\nthe central role of the phase of the fermion determinant in the possible\nrealization of such a scenario."
    },
    {
        "anchor": "Investigating $\\mathbf{N \\to N\u03c0}$ axial matrix elements: Excited state contamination is one of the most challenging sources of\nsystematics to tackle in the determination of nucleon matrix elements and form\nfactors. The signal-to-noise problem prevents one from considering large\nsource-sink time separations for the three-point functions to ensure ground\nstate dominance. Instead, relevant analyses consider multi-state fits. Excited\nstate contributions are particularly significant in the axial channel. In this\nwork, we confront the problem directly. Since the major source of contamination\nis understood to be related to pion production, we consider three-point\ncorrelation functions with a nucleon operator at the source and a nucleon-pion\ninterpolating operator at the sink, which allows studies of $N \\to N\\pi$ matrix\nelements. We discuss the construction of these three-point correlation\nfunctions and we solve the generalized eigenvalue problem (GEVP) using\ndifferent sets of nucleon and nucleon-pion interpolators. The analysis is\nperformed on the CLS ensemble A653 with $m_\\pi \\approx 420$ MeV. Results were\ngenerated with valence quark masses corresponding to $m_\\pi \\approx 1750$ MeV\nand $m_\\pi \\approx 420$ MeV.",
        "positive": "On the existence of the critical point in finite density lattice QCD: We propose a method to probe the nature of phase transitions in lattice QCD\nat finite temperature and density, which is based on the investigation of an\neffective potential as a function of the average plaquette. We analyze data\nobtained in a simulation of two-flavor QCD using p4-improved staggered quarks\nwith bare quark mass $m/T = 0.4$, and find that a first order phase transition\nline appears in the high density regime for $\\mu_q/T \\simge 2.5$. We also\ndiscuss the difference between the phase structures of QCD with non-zero quark\nchemical potential and non-zero isospin chemical potential."
    },
    {
        "anchor": "A $N_f = 2 + 1 + 1$ \"twisted\" determination of the $b$-quark mass,\n  $f_{B}$ and $f_{B_s}$: We present a lattice QCD determination of the $b$-quark mass and of the\n$f_{B_s}$ and $f_B$ decay constants performed with $N_f = 2 + 1 + 1$ twisted\nmass Wilson fermions. We have used simulations at three values of the lattice\nspacing generated by ETMC with pion masses ranging from 210 to 440 MeV. To\nobtain physical quantities we performed a combined chiral and continuum limit\nand an extrapolation in the heavy quark mass from the charm to the $b$-quark\nregion using suitable ratios calculated at nearby heavy-quark masses having an\nexactly known static limit. Our results are: $m_b(m_b) = 4.29 (13)$ GeV, $f_B =\n196 (9)$ MeV, $f_{B_s} = 235 (9)$ MeV, $f_{B_s} / f_B = 1.201 (25)$,\n$(f_{B_s}/f_B)/(f_K/f_\\pi) = 1.007 (16)$ and $(f_{B_s}/f_B)/(f_{D_s}/f_D) =\n1.008 (13)$.",
        "positive": "Anomaly non-renormalization, lattice QFT and universality of transport\n  coefficients: Recently new methods have been introduced to investigate the\nnon-renormalization properties of the anomalies at a non perturbative level and\nin presence of a lattice. The issue is relevant in a number of problems ranging\nfrom the anomaly-free construction of chiral lattice gauge theory with large\ncut-off to the universality properties observed in transport coefficients in\ncondensed matter systems. A review of main results and future perspectives is\npresented."
    },
    {
        "anchor": "Lattice gauge equivariant convolutional neural networks: We propose Lattice gauge equivariant Convolutional Neural Networks (L-CNNs)\nfor generic machine learning applications on lattice gauge theoretical\nproblems. At the heart of this network structure is a novel convolutional layer\nthat preserves gauge equivariance while forming arbitrarily shaped Wilson loops\nin successive bilinear layers. Together with topological information, for\nexample from Polyakov loops, such a network can in principle approximate any\ngauge covariant function on the lattice. We demonstrate that L-CNNs can learn\nand generalize gauge invariant quantities that traditional convolutional neural\nnetworks are incapable of finding.",
        "positive": "The renormalised quark mass in the Schrodinger functional of lattice QCD\n  - a one-loop calculation with a non-vanishing background field: The critical quark mass, at which the renormalised mass vanishes, is computed\nin the Schrodinger functional scheme with a non vanishing background field at\none-loop order of perturbation theory. Further one-loop calculations are done\nfor the renormalisation constant of the pseudo scalar density and for several\ndiscretisation errors and compared to results obtained with a vanishing\nbackground field."
    },
    {
        "anchor": "New developments in multi-meson systems: New developments in the study of multi-meson systems are reviewed. We\nhighlight a new recursive algorithm for generating the requisite contractions\nneeded for studying complex systems of mesons involving large numbers of\nparticles or multiple species of particles. First results on mixed species\nsystems involving pions and kaons are also presented.",
        "positive": "Supergravity from Gauge Theory: Gauge/gravity duality is the conjecture that string theories have dual\ndescriptions as gauge theories. Weakly-coupled gravity is dual to\nstrongly-coupled gauge theories, ideal for lattice calculations. I will show\nprecision lattice calculations that confirm large-N continuum D0-brane quantum\nmechanics correctly reproduces the leading-order supergravity prediction for a\nblack hole's internal energy---the first leading-order test of the\nduality---and constrains stringy corrections."
    },
    {
        "anchor": "Disconnected quark loop contributions to nucleon observables in lattice\n  QCD: We perform a high statistics calculation of disconnected fermion loops on\nGraphics Processing Units for a range of nucleon matrix elements extracted\nusing lattice QCD. The isoscalar electromagnetic and axial vector form factors,\nthe sigma-terms and the momentum fraction and helicity are among the quantities\nwe evaluate. We compare the disconnected contributions to the connected ones\nand give the physical implications on nucleon observables that probe its\nstructure.",
        "positive": "SU(3) gauge theory with sextet fermions: SU(3) gauge theory coupled to N_f = 2 fermions in the sextet representation\nis a promising candidate for a technicolor inspired Standard Model extension.\nIn this note the progress in the past few years aimed at understanding the\nnon-perturbative properties of the model is reviewed. The main difficulties\nlying ahead in order to make robust conclusions from lattice simulations are\noutlined."
    },
    {
        "anchor": "Deconfinement, Chiral Symmetry Breaking and Chiral Polarization: We examine the feasibility of the proposition that there is a temperature\nrange T$_c$ < T < T$_{ch}$ in N$_f$=0 QCD, where real Polyakov line\n(deconfined) vacuum exhibits valence spontaneous chiral symetry breaking and\ndynamical chiral polarization of Dirac eigenmodes. Detailed finite-volume\nanalysis convincingly demonstrates the existence of such phase at fixed cutoff\n(a=0.085 fm). Moreover, it is found that this behavior also takes place closer\nto the continuum limit (a=0.060 fm) without qualitative change in its\nproperties.",
        "positive": "Squared width and profile of the confining flux tube in the U(1) LGT in\n  3D: The dual formulation of the compact U(1) lattice gauge theory in three\nspacetime dimensions allows to finely study the squared width and the profile\nof the confining flux tube on a wide range of physical interquark distances.\nThe results obtained in Monte Carlo simulations are compared with the\npredictions of the effective bosonic-string model and with the dual\nsuperconductor model. While the former fails at describing the data from a\nquantitative point of view, the latter is in good agreement with it. An\ninterpretation of these results is proposed in light of the particular features\nof the U(1) lattice gauge theory in 3D and a comparison with non-Abelian gauge\ntheories in four spacetime dimensions is discussed."
    },
    {
        "anchor": "The IR gluon propagator from lattice QCD: The gluon propagator is computed in large asymmetric lattices, accessing\nmomenta around 100 MeV and smaller. Our study tries to check the compatibility\nof the recent solutions of the gluon-ghost Dyson-Schwinger equations with\nlattice results. In particular the exponent $\\kappa$, which characterizes the\nsolutions for the infrared, is measured. Results favours a vanishing zero\nmomentum gluon propagator. We also report on the compatibility of various\nfunctional forms used to fit the Dyson-Schwinger solution for the full range of\nmomenta and the lattice gluon propagator.",
        "positive": "Surface modes and parity violation in Schwinger model on the lattice: The phase diagram of the Schwinger model on the lattice with Wilson fermions\nis investigated in the Hartree-Fock approximation. In case of single flavour\n(not directly amenable to simulations), the calculation indicates the existence\nof the parity violating phase at both weak and intermediate-to-strong\ncouplings. Hartree-Fock vacuum sustains a nonzero electric field in this broken\nphase. The phase structure of the model with two flavours is also discussed."
    },
    {
        "anchor": "Form factors for semi-leptonic B decays: We report on form factors for the B->K l^+ l^- semi-leptonic decay process.\nWe use several lattice spacings from a=0.12 fm down to 0.06 fm and a variety of\ndynamical quark masses with 2+1 flavors of asqtad quarks provided by the MILC\nCollaboration. These ensembles allow good control of the chiral and continuum\nextrapolations. The b-quark is treated as a clover quark with the Fermilab\ninterpretation. We update our results for f_\\parallel and f_\\perp, or,\nequivalently, f_+ and f_0. In addition, we present new results for the tensor\nform factor f_T. Model independent results are obtained based upon the\nz-expansion.",
        "positive": "Precision computation of hybrid static potentials in SU(3) lattice gauge\n  theory: We perform a precision computation of hybrid static potentials with quantum\nnumbers $\\Lambda_\\eta^\\epsilon =\n\\Sigma_g^-,\\Sigma_u^+,\\Sigma_u^-,\\Pi_g,\\Pi_u,\\Delta_g,\\Delta_u$ using SU(3)\nlattice gauge theory. The resulting potentials are used to estimate masses of\nheavy $\\bar{c} c$ and $\\bar{b} b$ hybrid mesons in the Born-Oppenheimer\napproximation. Part of the lattice gauge theory computation, which we discuss\nin detail, is an extensive optimization of hybrid static potential creation\noperators. The resulting optimized operators are expected to be essential for\nfuture projects concerning the computation of 3-point functions as e.g. needed\nto study spin corrections, decays or the gluon distribution of heavy hybrid\nmesons."
    },
    {
        "anchor": "Adiabatic continuity and confinement in supersymmetric Yang-Mills theory\n  on the lattice: This work is a step towards merging the ideas that arise from semi-classical\nmethods in continuum QFT with analytic/numerical lattice field theory. In this\ncontext, we consider Yang-Mills theories coupled to fermions in the adjoint\nrepresentation. These theories have the remarkable property that confinement\nand discrete chiral symmetry breaking can persist at weak coupling on small\n(non-thermal) $\\mathbb R^3 \\times S^1$. This work presents a lattice\ninvestigation of Yang-Mills with one adjoint Majorana fermion, $\\mathcal N=1$\nsuper Yang-Mills, and opens the prospect to understand a number of\nnon-perturbative phenomena, such as the mechanism of confinement, mass gap,\nchiral and center symmetry realizations both in lattice and continuum\nanalytically. We study the compactification of this theory on the lattice with\nperiodic and thermal boundary conditions. We provide numerical evidence for the\nconjectured absence of the phase transitions with periodic boundary conditions\nfor sufficiently light lattice fermions (stability of center-symmetry),\nsuppression of the chiral transition, and also provide a diagnostic for abelian\nvs. non-abelian confinement, based on per-site Polyakov loop eigenvalue\ndistribution functions. In numerical and perturbative investigations we\nidentify the role of the lattice artefacts that become relevant in the very\nsmall radius regime, and resolve some puzzles in the naive comparison between\ncontinuum and lattice.",
        "positive": "Spectator Effects in Inclusive Decays of Beauty Hadrons: We evaluate the matrix elements of the four-quark operators which contribute\nto the lifetimes of $B$-mesons and the $\\Lambda_b$-baryon. We find that the\nspectator effects are not responsible for the discrepancy between the\ntheoretical prediction and experimental measurement of the ratio of lifetimes\n$\\tau(\\Lambda_b)/\\tau(B)$."
    },
    {
        "anchor": "Spin Effects in Heavy Hybrid Mesons on an Anisotropic Lattice: We present a quenched calculation of lowest bottomonium hybrid states on an\nanisotropic lattice with Landau mean-link tadpole improvement, using the\nimproved NRQCD Hamiltonian. We investigate the quark-spin s=0,1 sectors, which\ncontain both the non-exotic 1-- and the exotic 1-+, and demonstrate their\ndegeneracy in the case of the lowest order Hamiltonian. Both states are found\nat around 1.6 GeV above the Upsilon ground state. We examine the spin-splitting\nfor several hybrid states that is due to the magnetic moment term in the NRQCD\nHamiltonian, all other terms having negligible effect. The spin splittings are\nwell resolved outside errors and are surprisingly large, and we investigate\ntheir dependence on the strength of the magnetic term. We calculate one\ncontribution to these splittings using the Born-Oppenheimer picture for hybrids\nand show that the observed size of the effect is plausibly explained by mixing\nwith hybrid states with more than one constituent gluon.",
        "positive": "Lattice calculation of matrix elements relevant for Delta I=1/2 rule and\n  epsilon-prime: We have gained enough statistical precision to distinguish signal from noise\nin matrix elements of all operators relevant for the Delta I=1/2 rule in kaon\ndecays and for the direct CP violation parameter epsilon-prime. We confirm\nsignificant enhancement of Delta I=1/2 transitions observed in experiments,\nalthough a few large systematic uncertainties remain in our predictions:\nhigher-order chiral corrections and lattice spacing dependence. The estimate of\nepsilon-prime parameter is further complicated by the problem of matching\nlattice and continuum operators."
    },
    {
        "anchor": "Localization properties of lattice fermions with plaquette and improved\n  gauge actions: We determine the location $\\lambda_c$ of the mobility edge in the spectrum of\nthe hermitian Wilson operator in pure-gauge ensembles with plaquette, Iwasaki,\nand DBW2 gauge actions. The results allow mapping a portion of the (quenched)\nAoki phase diagram. We use Green function techniques to study the localized and\nextended modes. Where $\\lambda_c>0$ we characterize the localized modes in\nterms of an average support length and an average localization length, the\nlatter determined from the asymptotic decay rate of the mode density. We argue\nthat, since the overlap operator is commonly constructed from the Wilson\noperator, its range is set by the value of $\\lambda_c^{-1}$ for the Wilson\noperator. It follows from our numerical results that overlap simulations\ncarried out with a cutoff of 1 GeV, even with improved gauge actions, could be\nafflicted by unphysical degrees of freedom as light as 250 MeV.",
        "positive": "A Euclidean Lattice Construction of Supersymmetric Yang-Mills Theories\n  with Sixteen Supercharges: We formulate supersymmetric Euclidean spacetime Ad* lattices whose classical\ncontinuum limits are U(N) supersymmetric Yang-Mills theories with sixteen\nsupercharges in d=1,2,3 and 4 dimensions. This family includes the especially\ninteresting N=4 supersymmetry in four dimensions, as well as a Euclidean path\nintegral formulation of Matrix Theory on a one dimensional lattice."
    },
    {
        "anchor": "Static potential in the SU(2) Higgs model: We present results for the static potential in the confinement phase of the\nSU(2) Higgs model on the lattice. Introducing a suitable matrix correlation\nfunction we observe string breaking at a distance r_b ~ 1.8 r_0, where the\nlength scale r_0 has a value r_0 ~ 0.5 fm in QCD. The method presented here may\nlead the way towards a treatment of string breaking in QCD.",
        "positive": "Canonical Momenta in Digitized SU(2) Lattice Gauge Theory: Definition\n  and Free Theory: Hamiltonian simulations of quantum systems require a finite-dimensional\nrepresentation of the operators acting on the Hilbert space H. Here we give a\nprescription for gauge links and canonical momenta of an SU(2) gauge theory,\nsuch that the matrix representation of the former is diagonal in H. This is\nachieved by discretising the sphere $S_3$ isomorphic to SU(2) and the\ncorresponding directional derivatives. We show that the fundamental commutation\nrelations are fulfilled up to discretisation artefacts. Moreover, we directly\nconstruct the Casimir operator corresponding to the Laplace-Beltrami operator\non $S_3$ and show that the spectrum of the free theory is reproduced again up\nto discretisation effects. Qualitatively, these results do not depend on the\nspecific discretisation of SU(2), but the actual convergence rates do."
    },
    {
        "anchor": "A quenched study of the Schroedinger functional with chirally rotated\n  boundary conditions: applications: In a previous paper [1], we have discussed the non-perturbative tuning of the\nchirally rotated Schroedinger functional (XSF). This tuning is required to\neliminate bulk O(a) cutoff effects in physical correlation functions. Using our\ntuning results obtained in [1] we perform scaling and universality tests\nanalyzing the residual O(a) cutoff effects of several step-scaling functions\nand we compute renormalization factors at the matching scale. As an example of\npossible application of the XSF we compute the renormalized strange quark mass\nusing large volume data obtained from Wilson twisted mass fermions at maximal\ntwist.",
        "positive": "Analytic expansions of multi-hadron finite-volume energies: I.\n  Two-particle states: We derive analytic expansions for the finite-volume energies of\nweakly-interacting two-particle systems, using the general relations between\nscattering amplitudes and energies derived by L\\\"uscher and others. The\nrelations hold for ground and excited states with both zero and non-zero total\nmomentum in the finite-volume frame. A number of instructive aspects arise in\nthe derivation, including the role of accidental degeneracies and the\nimportance of defining a power-counting scheme in the expansions. The results\ngive intuition concerning the imprint of weakly-interacting systems on the\nenergy spectrum, while also providing a useful basis for the analogous results\nconcerning three-particle excited states, to appear."
    },
    {
        "anchor": "Monte Carlo Study of Strongly-Interacting Degenerate Fermions: a Model\n  for Voltage-Biased Bilayer Graphene: We formulate a model of N_f=4 flavors of relativistic fermion in 2+1d in the\npresence of a chemical potential mu coupled to two flavor doublets with\nopposite sign, akin to isopsin chemical potential in QCD. This is argued to be\nan effective theory for low energy electronic excitations in bilayer graphene,\nin which an applied voltage between the layers ensures equal populations of\nparticles on one layer and holes on the other. The model is then reformulated\non a spacetime lattice using staggered fermions, and in the absence of a sign\nproblem, simulated using an orthodox hybrid Monte Carlo algorithm. With the\ncoupling strength chosen to be close to a quantum critical point believed to\nexist for N_f<N_fc\\approx4.8, it is found that there is a region below\nsaturation where both the carrier density and a particle-hole \"excitonic\"\ncondensate scale anomalously with increasing mu, much more rapidly that the\ncorresponding quantities in free field theory, while the conventional chiral\ncondensate is strongly suppressed. The corresponding ground state is speculated\nto be a strongly-correlated degenerate fermion system, with a remnant Fermi\nsurface distorted by a superfluid excitonic condensate. The model thus shows\nqualitatively different behaviour to any model with mu=/=0 previously studied\nby lattice simulation.",
        "positive": "The Kaon B-parameter from Quenched Domain-Wall QCD: We present numerical results for the kaon B-parameter, B_K, determined in the\nquenched approximation of lattice QCD. Our simulations are performed using\ndomain-wall fermions and the renormalization group improved, DBW2 gauge action\nwhich combine to give quarks with good chiral symmetry at finite lattice\nspacing. Operators are renormalized non-perturbatively using the RI/MOM scheme.\nWe study scaling by performing the simulation on two different lattices with\na^{-1} = 1.982(30) and 2.914(54) GeV. We combine this quenched scaling study\nwith an earlier calculation of B_K using two flavors of dynamical, domain-wall\nquarks at a single lattice spacing to obtain\nB_K(MS,NDR,mu=2GeV)=0.563(21)(39)(30), were the first error is statistical, the\nsecond systematic (without quenching errors) and the third estimates the error\ndue to quenching."
    },
    {
        "anchor": "Stealth dark matter spectrum using LapH and Irreps: We present non-perturbative lattice calculations of the low-lying meson and\nbaryon spectrum of the SU(4) gauge theory with fundamental fermion\nconstituents. This theory is one instance of stealth dark matter, a class of\nstrongly coupled theories, where the lowest mass stable baryon is the dark\nmatter candidate. This work constitutes the first milestone in the program to\nstudy stealth dark matter self-interactions. Here, we focus on reducing excited\nstate contamination in the single baryon channel by applying the Laplacian\nHeaviside method, as well as projecting our baryon operators onto the\nirreducible representations of the octahedral group. We compare our resulting\nspectrum to previous work involving Gaussian smeared non-projected operators\nand find good agreement with reduced statistical uncertainties. We also present\nthe spectrum of the low-lying odd-parity baryons for the first time.",
        "positive": "Massless Decoupled Doublers: Chiral Yukawa Models and Chiral Gauge\n  Theories: We present a new method for regularizing chiral theories on the lattice. The\narbitrariness in the regularization is used in order to decouple massless\nreplica fermions. A continuum limit with only one fermion is obtained in\nperturbation theory and a Golterman-Petcher like symmetry related to the\ndecoupling of the replicas in the non-perturbative regime is identified. In the\ncase of Chiral Gauge Theories gauge invariance is broken at the level of the\nregularization, so our approach shares many of the characteristics of the Rome\napproach."
    },
    {
        "anchor": "Quantum Spins and Quantum Links: The D-Theory Approach to Field Theory: A new non-perturbative approach to quantum field theory is proposed. Instead\nof performing a path integral over configurations of classical fields, D-theory\nworks with discrete quantized variables. Classical spin fields are replaced by\nquantum spins, and classical gauge fields are replaced by quantum links. The\nclassical fields of a d-dimensional quantum field theory reappear as low-energy\neffective degrees of freedom of the discrete variables, provided the\n(d+1)-dimensional D-theory is massless. When the extent of the extra Euclidean\ndimension becomes small in units of the correlation length, an ordinary\nd-dimensional quantum field theory emerges by dimensional reduction. The\nD-theory formulation of some spin models and gauge theories is constructed\nexplicitly. In particular, QCD emerges as a quantum link model.",
        "positive": "Effective Lagrangian for the Polyakov line on a lattice: We formulate a method for computing the effective Lagrangian of the Polyakov\nline on the lattice. Using mean field approximation we calculate the effective\npotential for high temperatures. The result agrees with recent lattice\nsimulations. We reveal a new type of ultraviolet divergence (coming from\nlongitudinal gluons) which dominates the effective potential and explains the\ndiscrepancy of the lattice simulations and standard perturbative calculations\nperformed in covariant gauges."
    },
    {
        "anchor": "Possible New Phase of Thermal QCD: Using lattice simulations, we show that there is a phase of thermal QCD,\nwhere the spectral density $\\rho(\\lambda)$ of Dirac operator changes as\n$1/\\lambda$ for the infrared eigenvalues $\\lambda<T$. This behavior persists\nover the entire low energy band we can resolve accurately, over three orders of\nmagnitude on our largest volumes. We propose that in this \"IR phase\", the\nwell-known non-interacting scale invariance at very short distances (UV,\n$\\lambda \\rightarrow \\infty$, asymptotic freedom), coexists with very different\ninteracting type of scale invariance at long distances (IR, $\\lambda<T$). Such\ndynamics may be responsible for the unusual fluidity properties of the medium\nobserved at RHIC and LHC. We point out its connection to the physics of\nBanks-Zaks fixed point, leading to the possibility of massless glueballs in the\nfluid. Our results lead to the classification of thermal QCD phases in terms of\nIR scale invariance. The ensuing picture naturally subsumes the standard chiral\ncrossover feature at $\"\\!T_c\\!\" \\,\\approx 155$ MeV. Its crucial new aspect is\nthe existence of temperature $T_{IR}$ (200 MeV $< T_{IR} < $ 250 MeV) marking\nthe onset of IR phase and possibly a true phase transition.",
        "positive": "Lattice representation of vector and chiral gauge theories: A lattice derivative is defined as a discrete Fourier transform of momentum\non a finite lattice. Species doublers are removed with anti-periodic boundary\nconditions. U(1) chiral transformation is modified to reproduce chiral anomaly.\nChiral gauge theories can be constructed on the lattice using a single Weyl\nfermion as a building block."
    },
    {
        "anchor": "On Scale Determination in Lattice QCD with Dynamical Quarks: Dependence of $a/r_c$ (inverse Sommer parameter in units of lattice spacing\n$a$) on $am_q$ (quark mass in lattice unit) has been observed in all lattice\nQCD simulations with sea quarks including the ones with improved actions. How\nmuch of this dependence is a scaling violation has remained an intriguing\nquestion. Our approach has been to investigate the issue with an action with\nknown lattice artifacts, i.e., the standard Wilson quark and gauge action with\n$\\beta=5.6$ and 2 degenerate flavors of sea quarks on $ 16^3 \\times 32 $\nlattices. In order to study in detail the sea quark mass dependence,\nmeasurements are carried out at eight values of the Wilson hopping parameter\n$\\kappa$ in the range 0.156 - 0.158 corresponding to PCAC quark mass values\n$am_q$ from about 0.07 to below 0.015. We analyze the static potential by\nfitting to the familiar phenomenological form and extract $a/r_c$. Though\nscaling violations may indeed be present for relatively large $am_q$, a\nconsistent scenario at sufficiently small $am_q$ seems to emerge in the\nmass-independent scheme where for a fixed $\\beta$, $1/r_0$ and $\\sqrt{\\sigma}$\nhave linear dependence on $m_q$ as physical effects similar to the quark mass\ndependence of the rho mass. We present evidence for this scenario and\naccordingly extract the lattice scale $a$ by chiral extrapolation to the\nphysical point. Care has been exercised to determine optimal values of all\nfitting parameters and accuracy of the chiral extrapolation. An independent\ndetermination of the scale $a$ by chiral extrapolation of the rho mass is\nconsistent with the scale obtained above ($a$ = 0.08041(12)(77) fm, $a^{-1}$ =\n2.454(4)(23) GeV).",
        "positive": "Operator product expansion on the lattice: analytic Wilson coefficients: We present first results for Wilson coefficients of operators up to first\norder in the covariant derivatives for the case of Wilson fermions. They are\nderived from the off-shell Compton scattering amplitude\n$\\mathcal{W}_{\\mu\\nu}(a,p,q)$ of massless quarks with momentum $p$. The Wilson\ncoefficients are classified according to the transformation of the\ncorresponding operators under the hypercubic group H(4). We give selected\nexamples for a special choice of the momentum transfer $q$. All Wilson\ncoefficients are given in closed analytic form and in an expansion in powers of\n$a$ up to first corrections."
    },
    {
        "anchor": "Large logarithmic rescaling of the scalar condensate: new lattice\n  evidences: Using two different methods, we have determined the rescaling of the scalar\ncondensate $Z\\equiv Z_\\phi$ near the critical line of a 4D Ising model. Our\nlattice data, in agreement with previous numerical indications, support the\nbehavior $Z_\\phi\\sim \\ln ({\\Lambda})$, $\\Lambda$ being the ultraviolet cutoff.\nThis result is predicted in an alternative description of symmetry breaking\nwhere there are no upper bounds on the Higgs boson mass from `triviality'.",
        "positive": "Quark number susceptibilities at high temperatures: We calculate second and fourth order quark number susceptibilities for 2+1\nflavor QCD in the high temperature region. In our study we use two improved\nstaggered fermion formulations, namely the highly improved staggered quark\nformulation, and the so-called p4 formulation, as well as several lattice\nspacings. Second order quark number susceptibilities are calculated using both\nimproved staggered fermion formulations, and we show that in the continuum\nlimit the two formulations give consistent results. The fourth order quark\nnumber susceptibilities are studied only using the p4 formulation and at\nnon-zero lattice spacings. We compare our results on quark number\nsusceptibilities with recent weak coupling calculations, and find that these\nagree reasonably well with the lattice calculations within the estimated\nuncertainties."
    },
    {
        "anchor": "The dynamics of zero modes in lattice gauge theory---difference between\n  SU(2) and SU(3) in 4D: The dynamics of zero modes in gauge theory is highly nontrivial due to its\nnonperturbative nature even in the case where the other modes can be treated\nperturbatively. One of the related issues concerns the possible instability of\nthe trivial vacuum $A_\\mu(x)=0$ due to the existence of nontrivial degenerate\nvacua known as \"torons\". Here we investigate this issue for the 4D SU(2) and\nSU(3) pure Yang-Mills theories on the lattice by explicit Monte Carlo\ncalculation of the Wilson loops and the Polyakov line at large $\\beta$. While\nwe confirm the leading $1/\\beta$ predictions obtained around the trivial vacuum\nin both SU(2) and SU(3) cases, we find that the subleading term vanishes only\nlogarithmically in the SU(2) case unlike the power-law decay in the SU(3) case.\nIn fact, the 4D SU(2) case is marginal according to the criterion by Coste et\nal. Here we show that the trivial vacuum dominates in this case due to large\nfluctuations of the zero modes around it, thereby providing a clear\nunderstanding of the observed behaviors.",
        "positive": "Study of Instanton Contributions to Moments of Nucleon Spin-Dependent\n  Structure Functions: Instantons are the natural mechanism in non-perturbative QCD to remove\nhelicity from valence quarks and transfer it to gluons and quark-antiquark\npairs. To understand the extent to which instantons explain the so-called \"spin\ncrisis\" in the nucleon, we calculate moments of spin-dependent structure\nfunctions in quenched QCD and compare them with the results obtained with\ncooled configurations from which essentially all gluon contributions except\ninstantons have been removed. Preliminary results are presented."
    },
    {
        "anchor": "Determining the order of SU(3) deconfining phase transition: An effective spin model for the finite temperature non-abelian lattice gauge\ntheory is derived. The outcome is the surprising result that only nearest\nneighbor coupling survives, thus confirming the well known numerical results\nthat the deconfining phase transition of the (3+1)-dimensional $SU(3)$ pure\ngauge theory is first order.",
        "positive": "4d Simplicial Quantum Gravity with a Non-Trivial Measure: We study 4d simplicial quantum gravity in the dynamical triangulation\napproach with a non-trivial class of measures. We find that the measure\ncontribution plays an important role, influencing the phase diagram and the\nnature of the (possible) critical theory. We discuss how the lattice theory\ncould be used to fix the quantum measure in a non-ambiguous way."
    },
    {
        "anchor": "Lattice Simulations of the Thermodynamics of Strongly Interacting\n  Elementary Particles and the Exploration of New Phases of Matter in\n  Relativistic Heavy Ion Collisions: At high temperatures or densities matter formed by strongly interacting\nelementary particles (hadronic matter) is expected to undergo a transition to a\nnew form of matter - the quark gluon plasma - in which elementary particles\n(quarks and gluons) are no longer confined inside hadrons but are free to\npropagate in a thermal medium much larger in extent than the typical size of a\nhadron. The transition to this new form of matter as well as properties of the\nplasma phase are studied in large scale numerical calculations based on the\ntheory of strong interactions - Quantum Chromo Dynamics (QCD). Experimentally\nproperties of hot and dense elementary particle matter are studied in\nrelativistic heavy ion collisions such as those currently performed at the\nrelativistic heavy ion collider (RHIC) at BNL. We review here recent results\nfrom studies of thermodynamic properties of strongly interacting elementary\nparticle matter performed on Teraflops-Computer. We present results on the QCD\nequation of state and discuss the status of studies of the phase diagram at\nnon-vanishing baryon number density.",
        "positive": "Low energy effective action of domain-wall fermion and the\n  Ginsparg-Wilson relation: We derive the effective action of the light fermion field of the domain-wall\nfermion, which is referred as $q(x)$ by Furman and Shamir. The inverse of the\neffective Dirac operator turns out to be identical to the inverse of the\ntruncated overlap Dirac operator, except a local contact term which would give\nthe chiral symmetry breaking in the Ginsparg-Wilson relation. This result\nallows us to relate the light fermion field and the fermion field described by\nthe truncated overlap Dirac operator and to understand the chiral property of\nthe light fermion through the exact chiral symmetry based on the\nGinsparg-Wilson relation."
    },
    {
        "anchor": "Search for a bound H-dibaryon using local six-quark interpolating\n  operators: We present early results from a lattice QCD study seeking a bound\n$H$-dibaryon using $N_f=2$ flavors of $O(a)$ improved Wilson fermions and a\nquenched strange quark. We compute a matrix of two-point functions using\noperators consisting of the two independent local products of six\npositive-parity-projected quarks with the appropriate quantum numbers, which\nbelong to the singlet and 27-plet irreducible representations of flavor SU(3).\nTo expand this basis, we also independently vary the quark-field smearing, and\napply a new scheme to reduce the noise caused by smearing. We then find the\nground-state mass by solving the generalized eigenvalue problem. We show\nresults from ensembles with pion masses 451 MeV and 1 GeV, and compare with\nother lattice calculations.",
        "positive": "Distribution of Magnetic Monopoles within cubes in Compact QED: Earlier investigations showed local minima in the monopole-antimonopole\npotential in U(1) gauge theory on the lattice. In this paper we localize\nmonopoles of Monte-Carlo configurations. A statistical analysis of localization\nmeasurements gives us the probability density which we compare with the\npotential found in [1]. We find the monopoles mainly located either in the\ncenter of three-dimensional cubes or on the interface between two cubes. This\nagrees with the position of minima and maxima of the monopole-antimonopole\npotential."
    },
    {
        "anchor": "Supersymmetry breaking in two dimensions: the lattice N=1 Wess-Zumino\n  model: We study dynamical supersymmetry breaking by non perturbative lattice\ntechniques in a class of two-dimensional N=1 Wess-Zumino models. We work in the\nHamiltonian formalism and analyze the phase diagram by analytical\nstrong-coupling expansions and explicit numerical simulations with Green\nFunction Monte Carlo methods.",
        "positive": "GrassmannTN: a Python package for Grassmann tensor network computations: We present GrassmannTN, a Python package for the computation of the Grassmann\ntensor network. The package is built to assist in the numerical computation\nwithout the need to input the fermionic sign factor manually. It prioritizes\ncoding readability by designing every tensor manipulating function around the\ntensor subscripts. The computation of the Grassmann tensor renormalization\ngroup and Grassmann isometries using GrassmannTN are given as the use case\nexamples."
    },
    {
        "anchor": "Monte Carlo Study of the Yukawa Coupled Two Spin Ising Model: We consider a particular 4 state spin system composed of two Ising spins\n(~$s_x, \\; \\sigma_x$~) with independent hopping parameters $\\kappa_1,\n\\kappa_2$, coupled by a bilinear Yukawa term, $y s_x \\sigma_x$. The Yukawa term\nis solely responsible for breaking the global $ Z_2 \\times Z_2$ symmetry down\nto $Z_2$. This model is intended as an illustration of general coupled Higgs\nsystem where scalars can arise both as composite and elementary excitations.\nFor the Ising example in 2d, we give convincing numerical evidence of the\nuniversality of the two spin system with the one spin Ising model, by Monte\nCarlo simulations and finite scaling analysis . We also show that as we\napproach the phase transition, universality arises by a separation of low mass\nspin waves from an extra set of spin waves with an energy gap that diverges as\nthe correlations length diverges",
        "positive": "The electroweak sphaleron on the lattice: We study the properties of the electroweak sphaleron on a finite lattice. The\ncooling algorithm for saddle points is used to obtain the static classical\nsolutions of the SU(2)-Higgs field theory. Results are presented for\n$M_H=\\infty, M_W, 0.75M_W$. After performing finite size scaling we find good\nagreement with the results obtained from variational approaches. Of relevance\nfor numerical determinations of the transition rate is that the lattice\nartefacts are surprisingly small for $M_W\\approx M_H$."
    },
    {
        "anchor": "Logarithmic Corrections to Scaling in the $XY_2$--Model: We study the distribution of partition function zeroes for the $XY$--model in\ntwo dimensions. In particular we find the scaling behaviour of the end of the\ndistribution of zeroes in the complex external magnetic field plane in the\nthermodynamic limit (the Yang--Lee edge) and the form for the density of these\nzeroes. Assuming that finite--size scaling holds, we show that there have to\nexist logarithmic corrections to the leading scaling behaviour of thermodynamic\nquantities in this model. These logarithmic corrections are also manifest in\nthe finite--size scaling formulae and we identify them numerically. The method\npresented here can be used to check the compatibility of scaling behaviour of\nodd and even thermodynamic functions in other models too.",
        "positive": "Smearing and filtering methods in lattice QCD - a quantitative\n  comparison: We systematically compare three filtering methods used to extract topological\nexcitations from lattice gauge configurations, namely smearing, Laplace\nfiltering and the filtered fermionic topological charge (with chirally improved\nfermions). Each of these techniques introduces ambiguities, like its parameter\ndependence. We show, however, that all these methods can be tuned to each other\nover a broad range of filtering levels and that they reveal very similar\ntopological structures. For these common structures we find an interesting\npower-law relating the number and packing fraction of clusters of filtered\ntopological charge."
    },
    {
        "anchor": "Adaptive Step Size for Hybrid Monte Carlo Algorithm: We implement an adaptive step size method for the Hybrid Monte Carlo a\nlgorithm. The adaptive step size is given by solving a symmetric error\nequation. An integr ator with such an adaptive step size is reversible.\nAlthough we observe appreciable variations of the step size, the overhead of\nthe method exceeds its benefits. We propose an explanation for this phenomenon.",
        "positive": "Renormalization Group Invariant Matrix Elements of DS = 2 and DI = 3/2\n  Four-Fermion Operators without Quark Masses: We introduce a new parameterization of four-fermion operator matrix elements\nwhich does not involve quark masses and thus allows a reduction of systematic\nuncertainties. In order to simplify the matching between lattice and continuum\nrenormalization schemes, we express our results in terms of renormalization\ngroup invariant B-parameters which are renormalization-scheme and scale\nindependent. As an application of our proposal, matrix elements of DI=3/2 and\nSUSY DS =2 operators have been computed. The calculations have been performed\nusing the tree-level improved Clover lattice action at two different values of\nthe strong coupling constant (beta=6/g^2=6.0 and 6.2), in the quenched\napproximation. Renormalization constants and mixing coefficients of lattice\noperators have been obtained non-perturbatively. Using lowest order ChiPT, we\nalso obtain <Pi Pi| O_7|K >^{NDR}_{I=2} = (0.11\\pm 0.02) GeV^4 and <Pi Pi|\nO_8|K >^{NDR}_{I=2} = (0.51\\pm 0.05) GeV^4 at mu=2 GeV."
    },
    {
        "anchor": "The topological susceptibility and f_pi from lattice QCD: We study the topological susceptibility, chi, in QCD with two quark flavours\nusing lattice field configurations that have been produced with an O(a)\nimproved quark action. We find clear evidence for the expected suppression at\nsmall quark mass, and examine the variation of chi with this mass. The\nresulting estimate of the pion decay constant, f_pi = 105 +/- 6 ^{+18}_{-10}\nMeV, is consistent with the experimental value of ~93 MeV. We compare chi to\nthe large-N_c prediction and find consistency over a large range of quark\nmasses. We discuss the benefits of the non-perturbative action improvement\nscheme and of the stategy of keeping the lattice spacing (nearly) fixed as the\nquark mass is varied. We compare our results with other studies and suggest why\nsuch a quark mass dependence has not always been seen.",
        "positive": "Scaling Properties of the Probability Distribution of Lattice Gribov\n  Copies: We study the problem of the Landau gauge fixing in the case of the SU(2)\nlattice gauge theory. We show that the probability to find a lattice Gribov\ncopy increases considerably when the physical size of the lattice exceeds some\ncritical value $\\approx2.75/\\sqrt{\\sigma}$, almost independent of the lattice\nspacing. The impact of the choice of the copy on Green functions is presented.\nWe confirm that the ghost propagator depends on the choice of the copy, this\ndependence decreasing for increasing volumes above the critical one. The gluon\npropagator as well as the gluonic three-point functions are insensitive to\nchoice of the copy (within present statistical errors). Finally we show that\ngauge copies which have the same value of the minimisation functional ($\\int\nd^4x (A^a_\\mu)^2$) are equivalent, up to a global gauge transformation, and\nyield the same Green functions."
    },
    {
        "anchor": "Excited states and precision results for nucleon charges and form\n  factors: The exponentially falling signal-to-noise ratio in all nucleon correlation\nfunctions, and the presence of towers of multihadron excited states with\nrelatively small mass gaps makes extraction of matrix elements of various\noperators within the ground state nucleon challenging. Theoretically, the\nallowed positive parity states with the smallest mass gaps are the $N(\\bm\np)\\pi(-\\bm p)$, $N(\\bm 0)\\pi(\\bm 0)\\pi(\\bm 0)$, $N(\\bm p)\\pi(\\bm 0)$, $N(\\bm\n0)\\pi(\\bm p),\\ \\ldots$, states. A priori, the contribution of these states\narises at one loop in chiral perturbation theory ($\\chi$PT), however, in many\ncases the contributions are enhanced. In this talk, I will review four such\ncases: the correlation functions from which the axial form factors, electric\nand magnetic form factors, the $\\Theta$-term contribution to neutron electric\ndipole moment (nEDM), and the pion-nucleon sigma term are extracted. Including\nappropriate multihadron states in the analysis can lead to significantly\ndifferent results compared to standard analyses with the mass gaps taken from\nfits to 2-point functions. The $\\chi$PT case for $N \\pi$ states is the most\nclear in the axial/pseudoscalar form factors which need to satisfy the PCAC\nrelation between them. Our analyses, supported by $\\chi$PT, suggests similarly\nlarge effects in the calculations of the $\\Theta$-term and the pion-nucleon\nsigma term that have significant phenomenological implications.",
        "positive": "Topography of the hot sphaleron Transitions: By numerical simulations in {\\it real time} we provide evidence in favour of\nsphaleron like transitions in the hot, symmetric phase of the electroweak\ntheory. Earlier performed observations of a change in the Chern-Simons number\nare supplemented with a measurement of the lowest eigenvalues of the\nthree-dimensional staggered fermion Dirac operator and observations of the\nspatial extension of energy lumps associated with the transition. The\nobservations corroborate on the interpretation of the change in Chern-Simons\nnumbers as representing continuum physics, not lattice artifacts. By combining\nthe various observations it is possible to follow in considerable detail the\ntime-history of thermal fluctuations of the classical gauge-field\nconfigurations responsible for the change in the Chern-Simons number."
    },
    {
        "anchor": "Quenched charmonium near the continuum limit: We study relativistic charmonium on very fine quenched lattices (beta=6.4 and\n6.6). We concentrate on the calculation of the hyperfine splitting between\neta_c and J/psi, aiming for a controlled continuum extrapolation of this\nquantity. Results for the eta_c and J/psi wave functions are also presented.",
        "positive": "Testing the $\\mathrm{SU}(2)$ lattice Hamiltonian built from $S_3$\n  partitionings: We test a possible digitization of $\\mathrm{SU}(2)$ lattice gauge theories\nbased on partitionings of the sphere $S_3$. In our construction the link\noperators are unitary and diagonal, with eigenvalues determined by the vertices\nof the partitioning. The canonical momenta are finite difference operators\napproximating the Lie derivatives on the manifold. In this formalism we\nimplement the standard Wilson Hamiltonian. We show results for a 2-site\nSchwinger-type model in 1D and a single-plaquette system in 2D. Our\ncalculations are performed on a classical computer, though in principle they\ncan be implemented also on a quantum device."
    },
    {
        "anchor": "High Temperature QCD and Dimensional Reduction: In this talk I will first give a short discussion of some lattice results for\nQCD at finite temperature. I will then describe in some detail the technique of\ndimensional reduction, which in principle is a powerful technique to obtain\nresults on the long distance properties of the quark-gluon plasma. Finally I\nwill describe some new results, which test the technique in a simpler model,\nnamely three dimensional gauge theory.",
        "positive": "Observing Long Colour Flux Tubes in SU(2) Lattice Gauge Theory: We present results of a high statistics study of the chromo field\ndistribution between static quarks in SU(2) gauge theory on lattices of volumes\n16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm\nat beta=2.5, beta=2.635, and beta=2.74. We establish string formation over\nphysical distances as large as 2 fm. The results are tested against Michael's\nsum rules. A detailed investigation of the transverse action and energy flux\ntube profiles is provided. As a by-product, we obtain the static lattice\npotential in unpreceded accuracy."
    },
    {
        "anchor": "Solution of the Gribov problem from gauge invariance: A new approach to gauge fixed Yang-Mills theory is derived using the\nPolyakov-Susskind projection techniques to build gauge invariant states. In our\napproach, in contrast to the Faddeev-Popov method, the Gribov problem does not\nprevent the gauge group from being factored out of the partition function.\nLattice gauge theory is used to illustrate the method via a calculation of the\nstatic quark-antiquark potential generated by the gauge fields in the\nfundamental modular region of Coulomb gauge.",
        "positive": "Progress and prospects for heavy flavour physics on the lattice: I review recent progress in lattice computations relevant for $B$- and charm\nphysics, focusing on decay and mixing amplitudes with a direct impact on CKM\nanalysis. Emphasis is put on the interplay with the upcoming new generation of\nexperimental results, and the subsequent challenges for lattice computations in\nthe heavy quark sector."
    },
    {
        "anchor": "Lattice study of \"f$_{0}$(600) or $\u03c3$\": We investigate the propagator of \"f$_{0}$(600) or the $\\sigma$\" by the\nfull-QCD simulation with Wilson fermions. We calculate the mesonic correlator\nin the I=0, $J^P=0^{+}$ channel on the $8^{3} \\times 16$ lattice. Plaquet\naction and Wilson fermion action are adopted. A coupling constant $\\beta$ is\nset to 4.8 and three kinds of hopping parameter, $\\kappa$=0.1846, 0.1874 and\n0.1891 are assayed. The disconnected diagram in the propagator is evaluated\nthrough taking average over 500 or 1000 Z2 noise. Simulations with the larger\nhopping parameter provide us with less noisy results. Though the statistics is\nnot yet enough, our results indicate the existence of a pole with a mass in\nalmost the same order as that of the $\\rho$.",
        "positive": "Chiral fermions on a finite lattice: We discuss how to formulate Dirac fermion operator on a finite lattice such\nthat it can provide a nonperturbative regularization for massless fermion\ninteracting with a background gauge field."
    },
    {
        "anchor": "Confinement within the use of Minkowski space integral representation: We determine the gluonic spectral function $SU(3)$ Yang-Mills theory as well\nas we found fermionic spectral functions in the strong quenched QED where we\nfound new solutions. Our novel technique provides solutions with the usual\nbranch cut for propagators while not showing any pole structure at the first\nRiemann sheet (identical with entire complex plane) of complex square of\nmomentum. Implications and further utilizations are briefly adressed for QCD\nand Standard model calculations.",
        "positive": "Two-colour QCD at finite density with two flavours of staggered quarks: In this contribution we revisit simulations of two-color QCD with rooted\nstaggered quarks at finite density, where baryon-number spontaneously breaks\nand a diquark condensate forms. We thereby pay special attention to simulating\noutside the lattice-artifact bulk phase, in which $Z_2$ monopoles condense, and\ninvestigate some of the consequences of this, e.g. on the chiral and the\ndiquark condensate which were known to be well described by chiral effective\nfield theory. Not surprisingly, on finer lattices outside the bulk phase the\nquark condensate now requires additive renormalization before it can be\ncompared with effective field theory predictions. The subtraction must\nnecessarily depend on the chemical potential, however. The diquark condensate\nis not affected by this problem and remains in good agreement with these\npredictions. We also compare staggered with Wilson quarks to demonstrate that\nthe two fermion discretizations yield qualitatively different results well\nbelow half-filling already. We close with prelimiary results for the Goldstone\nspectrum to demonstrate that the continuum pattern is recovered also with\nstaggered quarks outside the bulk phase."
    },
    {
        "anchor": "QCD on GPUs: cost effective supercomputing: The exponential growth of floating point power in graphics processing units\n(GPUs), together with their low cost, has given rise to an attractive platform\nupon which to deploy lattice QCD calculations. GPUs are essentially many\n(O(100)) core chips, that are programmed using a massively threaded\nenvironment, and so are representative of the future of high performance\ncomputing (HPC). The large ratio of raw floating point operations per second to\nmemory bandwidth that is characteristic of GPUs necessitates that unique\nalgorithmic design choices are made to harness their full potential. We review\nthe progress to date in using GPUs for large scale calculations, and contrast\nGPUs against more traditional HPC architectures",
        "positive": "Towards fully bayesian analyses in Lattice QCD: We present a promising method to learn physical parameters from a bayesian\ninference, using modern tools to replace both our traditional fits and the way\nerrors are computed and propagated. A few models are built as illustrations for\na realistic case with Lattice QCD data, and appear to extract a lot of\ninformation with good stability. We discuss the evaluation of these models with\neither a fully bayesian approach or information criteria, as well as the\nmodel-building challenges which remain to be solved."
    },
    {
        "anchor": "Renormalization of infrared contributions to the QCD pressure: Thanks to dimensional reduction, the infrared contributions to the QCD\npressure can be obtained from two different three-dimensional effective field\ntheories, called the Electrostatic QCD (Yang-Mills plus adjoint Higgs) and the\nMagnetostatic QCD (pure Yang-Mills theory). Lattice measurements have been\ncarried out within these theories, but a proper interpretation of the results\nrequires renormalization, and in some cases also improvement, i.e. the removal\nof terms of O(a) or O(a^2). We discuss how these computations can be\nimplemented and carried out up to 4-loop level with the help of Numerical\nStochastic Perturbation Theory.",
        "positive": "Nuclear correlation functions in lattice QCD: We consider the problem of calculating the large number of Wick contractions\nnecessary to compute states with the quantum numbers of many baryons in lattice\nQCD. We consider a constructive approach and a determinant-based approach and\nshow that these methods allow the required contractions to be performed in\ncomputationally manageable amount of time for certain choices of interpolating\noperators. Examples of correlation functions computed using these techniques\nare shown for the quantum numbers of the light nuclei, He, Be, C, O and Si."
    },
    {
        "anchor": "Chiral phase transition in (2 + 1)-flavor QCD: The chiral phase transition temperature $T_{c}^{0}$ is a fundamental quantity\nof QCD. To determine this quantity we have performed simulations of (2 +\n1)-flavor QCD using the Highly Improved Staggered Quarks (HISQ/tree) action on\n$N_{\\tau}=6, 8$ and 12 lattices with aspect ratios $N_{\\sigma}/N_{\\tau}$\nranging from 4 to 8. In our simulations the strange quark mass is fixed to its\nphysical value $m_{s}^{\\rm{phy}}$, and the values of two degenerate light quark\nmasses $m_{l}$ are varied from $m_{s}^{\\rm{phy}}/20$ to $m_{s}^{\\rm{phy}}/160$\nwhich correspond to a Goldstone pion mass $m_{\\pi}$ ranging from 160 MeV to 55\nMeV in the continuum limit. By investigating the light quark mass dependence\nand the volume dependence of various chiral observables, e.g. chiral\nsusceptibilities and Binder cumulants, no evidence for a first order phase\ntransition in our current quark mass window is found. Two estimators $T_{60}$\nand $T_{\\delta}$ are proposed to extract the chiral phase transition\ntemperature $T_{c}^{0}$ in the chiral and continuum limit and our current\nestimate for $T_{c}^{0}$ is $132_{-6}^{+3}$ MeV.",
        "positive": "Determining Lines of Constant Physics in the Confinement Phase of the\n  SU(2) Higgs Model: We present a method for finding lines of constant physics in the confinement\nphase of the SU(2) Higgs model on the lattice. The model is considered at\nfinite values of the cut-off where it behaves like an effective field theory\nwith three independent couplings. In particular, a renormalised quantity\nsensitive to a variation of the bare Higgs quartic self-coupling is constructed\nfrom generalised Binder cumulants. Numerical results for the non-perturbative\nmatching of the bare parameters of the model between beta=2.2 and beta=2.4 are\npresented."
    },
    {
        "anchor": "Partially conserved axial vector current and applications: We investigate implications of the use of the point-split axial vector\ncurrent derived from a Wilson like fermionic action. We compute the\ncorresponding renormalization factor nonperturbatively for one beta value. The\naxial charge gA calculated from this nonlocal current is found to be nearer to\nthe physical value than computed with the local axial vector current --\ncomputed both on the same lattice with the same action.",
        "positive": "Tensor Network study of the (1+1)-dimensional Thirring Model: Tensor Network methods have been established as a powerful technique for\nsimulating low dimensional strongly-correlated systems for over two decades.\nEmploying the formalism of Matrix Product States, we investigate the phase\ndiagram of the massive Thirring model. We also show the possibility of studying\nsoliton dynamics and topological phase transition via the Thirring model."
    },
    {
        "anchor": "Fermion number anomaly with the fluffy mirror fermion: Quite recently, Grabowska and Kaplan presented a 4-dimensional lattice\nformulation of chiral gauge theories based on the chiral overlap operator. We\nstudy this formulation from the perspective of the fermion number anomaly and\npossible associated phenomenology. A simple argument shows that the consistency\nof the formulation implies that the fermion with the opposite chirality to the\nphysical one, the \"fluffy mirror fermion\" or \"fluff\", suffers from the fermion\nnumber anomaly in the same magnitude (with the opposite sign) as the physical\nfermion. This immediately shows that if at least one of the fluff quarks is\nmassless, the formulation provides a simple viable solution to the strong CP\nproblem. Also, if the fluff interacts with gravity essentially in the same way\nas the physical fermion, the formulation can realize the asymmetric dark matter\nscenario.",
        "positive": "Various Super Yang-Mills Theories with Exact Supersymmetry on the\n  Lattice: We continue to construct lattice super Yang-Mills theories along the line\ndiscussed in the previous papers \\cite{sugino, sugino2}. In our construction of\n${\\cal N}=2, 4$ theories in four dimensions, the problem of degenerate vacua\nseen in \\cite{sugino} is resolved by extending some fields and soaking up\nwould-be zero-modes in the continuum limit, while in the weak coupling\nexpansion some surplus modes appear both in bosonic and fermionic sectors\nreflecting the exact supersymmetry. A slight modification to the models is made\nsuch that all the surplus modes are eliminated in two- and three-dimensional\nmodels obtained by dimensional reduction thereof. ${\\cal N}=4, 8$ models in\nthree dimensions need fine-tuning of three and one parameters respectively to\nobtain the desired continuum theories, while two-dimensional models with ${\\cal\nN}=4, 8$ do not require any fine-tuning."
    },
    {
        "anchor": "Aspects of Dynamical Symmetry Breaking on a Lattice: In the context of four-fermion and gauge interactions, the Schwinger-Dyson\nequation for the fermion self-energy function is studied with the Wilson\nfermion on a lattice. We find that the critical line obtained by Bardeen, Leung\nand Love is modified. No additional Goldstone bosons appear in the spectrum of\nfundamental particles. Massive solutions to the Schwinger-Dyson equation turn\nout to be possible for a small gauge coupling.",
        "positive": "Fixed Scale Approach to Equation of State in Lattice QCD: A new approach to study the equation of state in finite-temperature QCD is\nproposed on the lattice. Unlike the conventional method in which the temporal\nlattice size $N_t$ is fixed, the temperature $T$ is varied by changing $N_t$ at\nfixed lattice scale. The pressure of the hot QCD plasma is calculated by the\nintegration of the trace anomaly with respect to $T$ at fixed lattice scale.\nThis \"$T$-integral method\" is tested in quenched QCD on isotropic and\nanisotropic lattices and is shown to give reliable results especially at\nintermediate and low temperatures."
    },
    {
        "anchor": "Summary Talk at Chiral '99: A brief summary of talks relating to massless lattice fermions is presented.\nThis summary is not a review and reading it certainly is no substitute to\nreading the various original contributions.",
        "positive": "Chiral symmetry restoration, eigenvalue density of Dirac operator and\n  axial U(1) anomaly at finite temperature: We reconsider constraints on the eigenvalue density of the Dirac operator in\nthe chiral symmetric phase of 2 flavor QCD at finite temperature. To avoid\npossible ultra-violet(UV) divergences, we work on a lattice, employing the\noverlap Dirac operator, which ensures the exact \"chiral\" symmetry at finite\nlattice spacings. Studying multi-point correlation functions in various\nchannels and taking their thermodynamical limit (and then taking the chiral\nlimit), we obtain stronger constraints than those found in the previous\nstudies: both the eigenvalue density at the origin and its first and second\nderivatives vanish in the chiral limit of 2 flavor QCD. In addition we show\nthat the axial U(1) anomaly becomes invisible in susceptibilities of scalar and\npseudo scalar mesons, suggesting that the 2nd order chiral phase transition\nwith the O(4) scaling is not realized in 2 flavor QCD. Possible lattice\nartifacts when non-chiral lattice Dirac operator is employed are briefly\ndiscussed."
    },
    {
        "anchor": "Domain wall fermions with improved gauge actions: We study the chiral properties of quenched domain wall fermions with several\ngauge actions. We demonstrate that the residual chiral symmetry breaking, which\nis present for a finite number of lattice sites in the fifth dimension ($L_s$),\ncan be substantially suppressed using improved gauge actions. In particular the\nSymanzik action, the Iwasaki action, and a renormalization group improved gauge\naction, called doubly blocked Wilson (DBW2), are studied and compared to the\nWilson action. All improved gauge actions studied show a reduction in the\nadditive residual quark mass, $\\mres$. Remarkably, in the DBW2 case $\\mres$ is\nroughly two orders of magnitude smaller than the Wilson gauge action at\n$a^{-1}=2$ GeV and $L_s=16$. Significant reduction in $\\mres$ is also realized\nat stronger gauge coupling corresponding to $a^{-1}=1.3$ GeV. As our numerical\ninvestigation indicates, this reduction is achieved by reducing the number of\ntopological lattice dislocations present in the gauge field configurations. We\nalso present detailed results for the quenched light hadron spectrum and the\npion decay constant using the DBW2 gauge action.",
        "positive": "openQ*D code: a versatile tool for QCD+QED simulations: We present the open-source package openQ*D-1.0, which has been primarily, but\nnot uniquely, designed to perform lattice simulations of QCD+QED and QCD, with\nand without C* boundary conditions, and O(a) improved Wilson fermions. The use\nof C* boundary conditions in the spatial direction allows for a local and\ngauge-invariant formulation of QCD+QED in finite volume, and provides a\ntheoretically clean setup to calculate isospin-breaking and radiative\ncorrections to hadronic observables from first principles. The openQ*D code is\nbased on openQCD-1.6 and NSPT-1.4. In particular it inherits from openQCD-1.6\nseveral core features, e.g. the highly optimized Dirac operator, the locally\ndeflated solver, the frequency splitting for the RHMC, or the 4th order OMF\nintegrator."
    },
    {
        "anchor": "B Physics From NRQCD With Dynamical Fermions: We present {\\it preliminary} results for the spectrum and decay constants of\nB mesons using NRQCD heavy and Wilson light quarks on configurations at\n$\\beta=5.6$ with two dynamical flavours of staggered fermions. All terms to\norder $1/M_Q$ are included in the NRQCD action; matrix elements are corrected\nto this order by calculating the small components of the heavy quark\npropagator.",
        "positive": "Exploring Bosonic and Fermionic Link Models on $(3+1)-$d tubes: Quantum link models (QLMs) have attracted a lot of attention in recent times\nas a generalization of Wilson's lattice gauge theories (LGT), and are\nparticularly suitable for realization on quantum simulators and computers.\nThese models are known to host new phases of matter and act as a bridge between\nparticle and condensed matter physics. In this article, we study the Abelian\n$U(1)$ lattice gauge theory in $(3+1)$-d tubes using large-scale exact\ndiagonalization (ED). We are then able to motivate the phase diagram of the\nmodel with finite size scaling techniques (FSS), and in particular propose the\nexistence of a Coulomb phase. Furthermore, we introduce the first models\ninvolving fermionic quantum links, which generalize the gauge degrees of\nfreedom to be of fermionic nature. We prove that while the spectra remain\nidentical between the bosonic and the fermionic versions of the\n$U(1)$-symmetric quantum link models in $(2+1)$-d, they are different in\n$(3+1)$-d. We discuss the prospects of realizing the magnetic field\ninteractions as correlated hopping in quantum simulator experiments."
    },
    {
        "anchor": "Isovector Charges of the Nucleon from 2+1+1-flavor Lattice QCD: We present high statistics results for the isovector charges $g^{u-d}_A$,\n$g^{u-d}_S$ and $g^{u-d}_T$ of the nucleon. Calculations were carried out on\neleven ensembles of gauge configurations generated by the MILC collaboration\nusing highly improved staggered quarks (HISQ) action with 2+1+1 dynamical\nflavors. These ensembles span four lattice spacings $a \\approx$ 0.06, 0.09,\n0.12 and 0.15 fm and light-quark masses corresponding to $M_\\pi \\approx$ 135,\n225 and 315 MeV. Excited-state contamination in the nucleon 3-point correlation\nfunctions is controlled by including up to three-states in the spectral\ndecomposition. Remaining systematic uncertainties associated with lattice\ndiscretization, lattice volume and light-quark masses are controlled using a\nsimultaneous fit in these three variables. Our final estimates of the isovector\ncharges in the $\\overline{\\text{MS}}$ scheme at 2 GeV are $g_A^{u-d} =\n1.218(25)(30)$, $g_S^{u-d} = 1.022(80)(60) $ and $g_T^{u-d} = 0.989(32)(10)$.\nThe first error includes statistical and all systematic uncertainties except\nthat due to the extrapolation ansatz, which is given by the second error\nestimate. We provide a detailed comparison with the recent result of $g_A^{u-d}\n= 1.271(13)$ by the CalLat collaboration and argue that our error estimate is\nmore realistic. Combining our estimate for $g_S^{u-d}$ with the difference of\nlight quarks masses $(m_d-m_u)^{\\rm QCD}=2.572(66)$ MeV given by the\nMILC/Fermilab/TUMQCD collaboration for 2+1+1-flavor theory, we obtain\n$(M_N-M_P)^{\\rm QCD} = 2.63(27)$ MeV. We update the low-energy constraints on\nnovel scalar and tensor interactions, $\\epsilon_{S}$ and $\\epsilon_{T}$, at the\nTeV scale by combining our new estimates for $g^{u-d}_S$ and $g^{u-d}_T$ with\nprecision low-energy nuclear experiments, and find them comparable to those\nfrom the ATLAS and the CMS experiments at the LHC.",
        "positive": "Avoiding the boson sign problem at finite chemical potential: The usual path integral formulation for scalar particles at finite density\ninvolves a sign problem, making numerical simulation impractical. We present\nalternative methods free of this difficulty. We apply these approaches to phi^4\ntheory in 2+1 dimensions, presenting preliminary numerical results for physical\nquantities in the vicinity of the phase transition in the T-mu plane."
    },
    {
        "anchor": "Non-perturbative phase structure of the bosonic BMN matrix model: We study the bosonic part of the BMN matrix model for wide ranges of\ntemperatures, values of the deformation parameter, and numbers of colors $16\n\\leq N \\leq 48$. Using lattice computations, we analyze phase transitions in\nthe model, observing a single first-order transition from a uniform to a gapped\nphase for all values of the deformation parameter. We study the functional form\nof the dependence of the critical temperature on the deformation parameter, to\ndescribe how our results smoothly interpolate between the limits of the bosonic\nBFSS model and the gauged Gaussian model.",
        "positive": "The density in the density of states method: It has been suggested that for QCD at finite baryon density the distribution\nof the phase angle, i.e. the angle defined as the imaginary part of the\nlogarithm of the fermion determinant, has a simple Gaussian form. This\ndistribution provides the density in the density of states approach to the sign\nproblem. We calculate this phase angle distribution using i) the hadron\nresonance gas model; and ii) a combined strong coupling and hopping parameter\nexpansion in lattice gauge theory. While the former model leads only to a\nGaussian distribution, in the latter expansion we discover terms which cause\nthe phase angle distribution to deviate, by relative amounts proportional to\npowers of the inverse lattice volume, from a simple Gaussian form. We show that\ndespite the tiny inverse-volume deviation of the phase angle distribution from\na simple Gaussian form, such non-Gaussian terms can have a substantial impact\non observables computed in the density of states/reweighting approach to the\nsign problem."
    },
    {
        "anchor": "Quantum Algorithms for Open Lattice Field Theory: Certain aspects of some unitary quantum systems are well-described by\nevolution via a non-Hermitian effective Hamiltonian, as in the Wigner-Weisskopf\ntheory for spontaneous decay. Conversely, any non-Hermitian Hamiltonian\nevolution can be accommodated in a corresponding unitary system + environment\nmodel via a generalization of Wigner-Weisskopf theory. This demonstrates the\nphysical relevance of novel features such as exceptional points in quantum\ndynamics, and opens up avenues for studying many body systems in the complex\nplane of coupling constants. In the case of lattice field theory, sparsity\nlends these channels the promise of efficient simulation on standardized\nquantum hardware. We thus consider quantum operations that correspond to\nSuzuki-Lee-Trotter approximation of lattice field theories undergoing\nnon-Hermitian time evolution, with potential applicability to studies of spin\nor gauge models at finite chemical potential, with topological terms, to\nquantum phase transitions - a range of models with sign problems. We develop\nnon-Hermitian quantum circuits and explore their promise on a benchmark, the\nquantum one-dimensional Ising model with complex longitudinal magnetic field,\nshowing that observables can probe the Lee-Yang edge singularity. The\ndevelopment of attractors past critical points in the space of complex\ncouplings indicates a potential for study on near-term noisy hardware.",
        "positive": "Probing the topological structure of the QCD vacuum with overlap\n  fermions: Overlap fermions implement exact chiral symmetry on the lattice and are thus\nan appropriate tool for investigating the chiral and topological structure of\nthe QCD vacuum. We study various chiral and topological aspects on\nLuescher-Weisz-type quenched gauge field configurations using overlap fermions\nas a probe. Particular emphasis is placed upon the analysis of the spectral\ndensity and the localisation properties of the eigenmodes as well as on the\nlocal structure of topological charge fluctuations."
    },
    {
        "anchor": "The QCD crossover at finite chemical potential from lattice simulations: We provide the most accurate results for the QCD transition line so far. We\noptimize the definition of the crossover temperature $T_c$, allowing for its\nvery precise determination, and extrapolate from imaginary chemical potential\nup to real $\\mu_B \\approx 300$ MeV. The definition of $T_c$ adopted in this\nwork is based on the observation that the chiral susceptibility as a function\nof the condensate is an almost universal curve at zero and imaganiary $\\mu_B$.\nWe obtain the parameters $\\kappa_2=0.0153(18)$ and $\\kappa_4=0.00032(67)$ as a\ncontinuum extrapolation based on $N_t=10,12$ and $16$ lattices with physical\nquark masses. We also extrapolate the peak value of the chiral susceptibility\nand the width of the chiral transition along the crossover line. In fact, both\nof these are consistent with a constant function of $\\mu_B$. We see no sign of\ncriticality in the explored range.",
        "positive": "A Numerical Study of Spectral Flows of Hermitian Wilson-Dirac Operator\n  and the Index Theorem in Abelian Gauge Theories on Finite Lattices: We investigate the index of the Neuberger's Dirac operator in abelian gauge\ntheories on finite lattices by numerically analyzing the spectrum of the\nhermitian Wilson-Dirac operator for a continuous family of gauge fields\nconnecting different topological sectors. By clarifying the characteristic\nstructure of the spectrum leading to the index theorem we show that the index\ncoincides to the topological charge for a wide class of gauge field\nconfigurations. We also argue that the index can be found exactly for some\nspecial but nontrivial configurations in two dimensions by directly analyzing\nthe spectrum."
    },
    {
        "anchor": "The strong coupling constant from lattice QCD with N_f=2 dynamical\n  quarks: We compute $\\Lambda_{\\bar{MS}}$ for two flavors of light dynamical quarks\nusing non-perturbatively $O(a)$ improved Wilson fermions. We improve on a\nrecent calculation by employing Pad\\'e-improved two-loop and three-loop\nperturbation theory to convert the lattice numbers to the $\\bar{MS}$ scheme.",
        "positive": "Simple patterns for non-linear susceptibilities near T_c: Non-linear susceptibilities upto the eighth order have been constructed in\nQCD with 2 flavours of dynamical quarks. Beyond leading order, they exhibit\npeaks at the cross over temperature, T_c. By analyzing their behaviour in\ndetail, we find that the dominant contributions near T_c come from a set of\noperators with a remarkably simple topology. Any effective theory of QCD near\nT_c must be able to explain these regularities."
    },
    {
        "anchor": "Chiral Lattice Fermions From Staggered Fields: We describe a proposal for constructing a lattice theory that we argue may be\ncapable of yielding free Weyl fermions in the continuum limit. The model\nemploys reduced staggered fermions and uses site parity dependent Yukawa\ninteractions of Fidkowski-Kitaev type to gap a subset of the lattice fermions\nwithout breaking symmetries. The possibility for such symmetric mass generation\nis tied to the cancellation of certain discrete anomalies arising in the\ncontinuum limit. The latter place strong constraints on the number of lattice\nfermions -- constraints that are satisfied by this model. We present numerical\nresults for the model in two dimensions which support this sc",
        "positive": "Non-perturbative renormalization and running of Delta F=2 four-fermion\n  operators in the SF scheme: We present preliminary results of a non-perturbative study of the\nscale-dependent renormalization constants of a complete basis of Delta F=2\nparity-odd four-fermion operators that enter the computation of hadronic\nB-parameters within the Standard Model (SM) and beyond. We consider\nnon-perturbatively O(a) improved Wilson fermions and our gauge configurations\ncontain two flavors of massless sea quarks. The mixing pattern of these\noperators is the same as for a regularization that preserves chiral symmetry,\nin particular there is a \"physical\" mixing between some of the operators. The\nrenormalization group running matrix is computed in the continuum limit for a\nfamily of Schrodinger Functional (SF) schemes through finite volume recursive\ntechniques. We compute non-perturbatively the relation between the\nrenormalization group invariant operators and their counterparts renormalized\nin the SF at a low energy scale, together with the non-perturbative matching\nmatrix between the lattice regularized theory and the various SF schemes."
    },
    {
        "anchor": "Confinement and string breaking for QED$_2$ in the Hamiltonian picture: The formalism of matrix product states is used to perform a numerical study\nof 1+1 dimensional QED -- also known as the (massive) Schwinger model -- in the\npresence of an external static `quark' and `antiquark'. We obtain a detailed\npicture of the transition from the confining state at short interquark\ndistances to the broken-string `hadronized' state at large distances and this\nfor a wide range of couplings, recovering the predicted behavior both in the\nweak and strong coupling limit of the continuum theory. In addition to the\nrelevant local observables like charge and electric field, we compute the\n(bipartite) entanglement entropy and show that subtraction of its vacuum value\nresults in a UV-finite quantity. We find that both string formation and string\nbreaking leave a clear imprint on the resulting entropy profile. Finally, we\nalso study the case of fractional probe charges, simulating for the first time\nthe phenomenon of partial string breaking.",
        "positive": "Extracting the Pion Distribution Amplitude from Lattice QCD through\n  Pseudo-Distributions: The Light-Cone Distribution Amplitude (LCDA) encodes the non-perturbative\ninformation of the leading Fock component of the hadron wave function,\ntherefore required for processes including exclusive hadron production. As the\npseudo-Nambu-Goldstone boson of QCD, the nonperturbative structure of the pion\nis of particular interest. Progress on the Lattice QCD calculation of the pion\nLCDA on ${\\cal O}(a)$-improved Wilson fermion ensembles at several lattice\nspacings is presented. Excited-state systematics are taken into account within\na Bayesian Model Averaging framework. A Renormalization-Group-Invariant (RGI)\nratio of matrix elements is formed for further extraction of the pion LCDA."
    },
    {
        "anchor": "Monopole and instanton effects on connected and disconnected\n  correlations for scalar density: This study investigates the effects on the connected and disconnected\ncorrelations for the scalar density that are induced by created monopoles and\ninstantons in the QCD vacuum. To reveal the effects, we add a monopole and\nanti-monopole pair in the gauge field configurations in \\textit{SU}(3) by\napplying the monopole creation operator to the vacuum. We vary the magnetic\ncharges of the monopole and anti-monopole and increase the number of monopoles\nand anti-monopoles in the configurations. The Dirac operator of overlap\nfermions preserves the exact chiral symmetry in lattice gauge theory and exact\nzero-modes exist in its spectrum. The eigenvalues and eigenvectors of the\noverlap Dirac operator have been calculated using these configurations, and the\nnumbers of instantons and anti-instantons which are created by these additional\nmonopoles and anti-monopoles have been estimated from the numbers of\ntopological charges in our previous studies. In this study, we demonstrate the\npreliminary results that instantons and monopoles influence the masses that are\nevaluated from the connected and disconnected correlation functions for the\nscalar density using low-lying eigenvalues and eigenvectors of the overlap\nDirac operator.",
        "positive": "Progress in kaon physics on the lattice: CKM-unitarity, direct and indirect CP-violation and the \\Delta I=1/2 rule in\nfull lattice QCD are the focus of this talk. To this end I will discuss and\ncompare recent lattice results for leptonic, semi-leptonic and non-leptonic\ndecays of the kaon and neutral kaon mixing and I will motivate current best\nestimates f_K/f_\\pi=1.198(10), f_+^{K\\pi}(0)=0.964(5) and \\hat{B}_K=0.720(39).\nMoreover new theoretical advances that will improve the quality of these\ncomputations in the future will be discussed."
    },
    {
        "anchor": "The hadronic vacuum polarization function with O(a)-improved Wilson\n  fermions - an update: We present an update of our lattice QCD study of the vacuum polarization\nfunction using O$(a)$-improved $N_ {\\rm f} =2$ Wilson fermions with increased\nstatistics and a large set of momenta. The resulting points are highly\ncorrelated and thus require a correlated fitting procedure. We employ an\nextended frequentist method to estimate the systematic uncertainties due to the\nmomentum dependence and to the continuum and chiral extrapolations. We present\npreliminary results of the leading order hadronic contribution of the anomalous\nmagnetic moment of the muon $\\left(a_\\mu^{\\mathrm{HLO}}\\right)$ at the physical\npoint for $u,d,s$ and $c$ valence quarks.",
        "positive": "Domain wall fermions in vector theories: Applications of Domain Wall fermions to various vector-like lattice theories\nare reviewed with an emphasis on QCD thermodynamics. Methods for improving\ntheir chiral properties at strong coupling are discussed and results from\nimplementing them are presented."
    },
    {
        "anchor": "Measuring the aspect ratio renormalization of anisotropic-lattice gluons: Using tadpole inproved actions we investigate the consistency between\ndifferent methods of measuring the aspect ratio renormalization of\nanisotropic-lattice gluons for bare aspect ratios \\chi_0=4,6,10 and inverse\nlattice spacing in the range a_s^{-1}=660-840 MeV. The tadpole corrections to\nthe action, which are established self-consistently, are defined for two cases,\nmean link tadpoles in Landau gauge and gauge invariant mean plaquette tadpoles.\nParameters in the latter case exhibited no dependence on the spatial lattice\nsize, L, while in the former, parameters showed only a weak dependence on L\neasily extrapolated to L=\\infty.\n  The renormalized anisotropy \\chi_R was measured using both the torelon\ndispersion relation and the sideways potential method. We found good agreement\nbetween these different approaches. Any discrepancy was at worst 3-4% which is\nconsistent with the effect of lattice artifacts that for the torelon we\nestimate as O(\\a_Sa_s^2/R^2) where R is the flux-tube radius.\n  We also present some new data that suggests that rotational invariance is\nestablished more accurately for the mean-link action than the plaquette action.",
        "positive": "Status of the apeNEXT project: We present the current status of the apeNEXT project. Aim of this project is\nthe development of the next generation of APE machines which will provide\nmulti-teraflop computing power. Like previous machines, apeNEXT is based on a\ncustom designed processor, which is specifically optimized for simulating QCD.\nWe discuss the machine design, report on benchmarks, and give an overview on\nthe status of the software development."
    },
    {
        "anchor": "Distributions of the Phase Angle of the Fermion Determinant in QCD: The distribution of the phase angle and the magnitude of the fermion\ndeterminant as well as its correlations with the baryon number and the chiral\ncondensate are studied for QCD at non zero quark chemical potential. Results\nare derived to one-loop order in chiral perturbation theory. We find that the\ndistribution of the phase angle is Gaussian for small chemical potential and a\nperiodic Lorentzian when the quark mass is inside the support of the Dirac\nspectrum. The baryon number and chiral condensate are computed as a function of\nthe phase of the fermion determinant and we discuss the severe cancellations\nwhich occur upon integration over the angle. We compute the distribution of the\nmagnitude of the fermion determinant as well as the baryon number and chiral\ncondensate at fixed magnitude.\n  Finally, we consider QCD in one Euclidean dimension where it is shown\nanalytically, starting from the fundamental QCD partition function, that the\ndistribution of the phase of the fermion determinant is a periodic Lorentzian\nwhen the quark mass is inside the spectral density of the Dirac operator.",
        "positive": "Glue Spin $S_G$ in The Longitudinally Polarized Nucleon: We present a lattice QCD calculation of the glue spin $S_G$ in the nucleon\nfor the first time. It was recently shown that the first moment of the glue\nhelicity distribution could be obtained through the cross-product of the the\nelectric field $\\vec{E}$ and the physical gauge field $\\vec{A}_{phys}$ with the\nnon-Abelian Coulomb gauge condition, i.e. $\\int d^3 x\\, \\,\\vec{E}(x) \\times\n\\vec{A}_{phys}(x)$ in the infinite momentum frame. We use the gauge field\ntensor from the overlap Dirac operator to check the frame dependence and\ncalculate glue spin with several momenta. The calculation is carried out with\nvalence overlap fermion on 2+1 flavor DWF gauge configurations on the $24^3\n\\times 64$ lattice with $a^{-1}=1.77$ GeV with the light sea quark mass\ncorresponding to a pion mass of 330 MeV."
    },
    {
        "anchor": "First determination of the strange and light quark masses from full\n  lattice QCD: We compute the strange quark mass $m_s$ and the average of the $u$ and $d$\nquark masses $\\hat m$ using full lattice QCD with three dynamical quarks\ncombined with experimental values for the pion and kaon masses. The simulations\nhave degenerate $u$ and $d$ quarks with masses $m_u=m_d\\equiv \\hat m$ as low as\n$m_s/8$, and two different values of the lattice spacing. The bare lattice\nquark masses obtained are converted to the $\\msbar$ scheme using perturbation\ntheory at $O(alpha_s)$. Our results are: $m_s^\\msbar$(2 GeV) = 76(0)(3)(7)(0)\nMeV, $\\hat m^\\msbar$(2 GeV) = 2.8(0)(1)(3)(0) MeV and $m_s/\\hat m$ =\n27.4(1)(4)(0)(1), where the errors are from statistics, simulation,\nperturbation theory, and electromagnetic effects, respectively.",
        "positive": "Conserved charge fluctuations at vanishing net-baryon density from\n  Lattice QCD: We present here continuum extrapolated results for all 2nd order cumulants\nusing the most recent results obtained by the HotQCD collaboration in\n(2+1)-flavor QCD. We constrain the applicability of various HRG models by\npresenting a detailed comparison of our results based on different sets of\nhadron spectra as well as with virial expansion based model calculations. A\ncomparison with our lattice QCD results for 2nd order cumulants with models\nthat parametrize repulsive interactions among baryons and anti-baryons in a\nhadron resonance gas through a single excluded volume parameter (EVHRG) is also\nshown."
    },
    {
        "anchor": "Computation of the quarkonium and meson-meson composition of the\n  $\u03a5(nS)$ states and of the new $\u03a5(10753)$ Belle resonance from\n  lattice QCD static potentials: We compute the composition of the bottomonium $\\Upsilon(nS)$ states\n(including $\\Upsilon(10860)$) and the new $\\Upsilon(10753)$ resonance reported\nby Belle in terms of quarkonium and meson-meson components. We use a recently\ndeveloped novel approach utilizing lattice QCD string breaking potentials for\nthe study of resonances. This approach is based on the Born Oppenheimer\napproximation and the unitary emergent wave method and allows to compute the\npoles of the $\\mbox{S}$ matrix. We focus on $I=0$ bottomonium $S$ wave bound\nstates and resonances, where the Schr\\\"odinger equation is a set of coupled\ndifferential equations. One of the channels corresponds to a confined heavy\nquark-antiquark pair $\\bar b b$, the others to pairs of heavy-light mesons. In\na previous study only one meson-meson channel $\\bar{B}^{(\\ast)} B^{(\\ast)}$ was\nconsidered. Now we also include the closed strangeness channel\n$\\bar{B}_s^{(\\ast)} B_s^{(\\ast)}$ extending our formalism significantly to have\na more realistic description of bottomonium. We confirm the new Belle resonance\n$\\Upsilon(10753)$ as a dynamical meson-meson resonance with around $85 \\%$\nmeson-meson content. Moreover, we identify $\\Upsilon(4S)$ and $\\Upsilon(10860)$\nas states with both sizable quarkonium and meson-meson contents. With these\nresults we contribute to the clarification of ongoing controversies in the\nvector bottomonium spectrum.",
        "positive": "Calculating the running coupling in strong electroweak models: One possibility for Beyond Standard Model physics is a new\nstrongly-interacting gauge theory. One way to determine if a non-abelian gauge\ntheory is QCD-like or conformal is to measure the running of the renormalized\ngauge coupling. We define the renormalized coupling from Wilson loop ratios,\nand measure these ratios via lattice simulations. We test this method in SU(3)\npure gauge theory and show some first results for simulations with dynamical\nfermions in the fundamental representation."
    },
    {
        "anchor": "Critical behaviour of the Ginzburg-Landau model in the type II region: We study the critical behaviour of the three-dimensional U(1) gauge+Higgs\ntheory (Ginzburg-Landau model) at large scalar self-coupling \\lambda (``type II\nregion'') by measuring various correlation lengths as well as the\nAbrikosov-Nielsen-Olesen vortex tension. We identify different scaling regions\nas the transition is approached from below, and carry out detailed comparisons\nwith the criticality of the 3d O(2) symmetric scalar theory.",
        "positive": "Resonance properties from lattice energy levels using chiral effective\n  field theory: We use the chiral effective field theory to study the lattice finite-volume\nenergy levels from the meson-meson scattering. The hadron resonance properties\nand the scattering amplitudes at physical masses are determined from the\nlattice energy levels calculated at unphysically large pion masses. The results\nfrom the $\\pi\\eta, K\\bar{K}$ and $\\pi\\eta'$ coupled-channel scattering and the\n$a_0(980)$ resonance are explicitly given as a concrete example."
    },
    {
        "anchor": "Review of lattice results concerning low-energy particle physics: We review lattice results related to pion, kaon, D- and B-meson physics with\nthe aim of making them easily accessible to the particle physics community.\nMore specifically, we report on the determination of the light-quark masses,\nthe form factor f+(0), arising in the semileptonic K -> pi transition at zero\nmomentum transfer, as well as the decay constant ratio fK/fpi and its\nconsequences for the CKM matrix elements Vus and Vud. Furthermore, we describe\nthe results obtained on the lattice for some of the low-energy constants of\nSU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory. We review the\ndetermination of the BK parameter of neutral kaon mixing as well as the\nadditional four B parameters that arise in theories of physics beyond the\nStandard Model. The latter quantities are an addition compared to the previous\nreview. For the heavy-quark sector, we provide results for mc and mb (also new\ncompared to the previous review), as well as those for D- and B-meson decay\nconstants, form factors, and mixing parameters. These are the heavy-quark\nquantities most relevant for the determination of CKM matrix elements and the\nglobal CKM unitarity-triangle fit. Finally, we review the status of lattice\ndeterminations of the strong coupling constant alpha_s.",
        "positive": "On the interrelation between monopoles, vortices, topological charge and\n  chiral symmetry breaking: an analysis using overlap fermions for SU(2): We study the properties of configurations from which P-vortices on one hand\nor Abelian monopoles on the other hand have been removed. We find that the zero\nmodes and the band of non-zero modes close to zero disappear from the spectrum\nof the overlap Dirac operator, confirming the absence of topological charge and\nquark condensate. The different behavior of the modified ensembles under\nsmearing compared to the unmodified Monte Carlo ensemble corroborates these\nfindings. The gluonic topological susceptibility rapidly approaches zero in\naccordance with Q_{index}=0. The remaining (ultraviolet) monopoles without\nvortices and -- to a less extent -- the remaining vortices without monopoles\nare unstable under smearing whereas smearing of the unmodified Monte Carlo\nensemble effects the monopoles and vortices only by smoothing, reducing the\ndensity only slightly."
    },
    {
        "anchor": "Aspects of the thermal phase transition of QCD with small chemical\n  potential: We propose a new method to investigate the thermal properties of QCD with a\nsmall chemical potential $(\\mu)$. The derivatives of the phase transition point\nwith respect to $\\mu$ are computed for 2 flavors of p4-improved staggered\nfermions. We moreover comment on the complex phase of the fermion determinant\nin finite-density QCD.",
        "positive": "On static quark anti-quark potential at non-zero temperature: We study Wilson loops at non-zero temperature and extract the static quark\npotential from them. The extracted potentials are larger than the singlet free\nenergies and do not show screening for $T<190$ MeV."
    },
    {
        "anchor": "Study of SU(3) vortex-like configurations with a new maximal center\n  gauge fixing method: We present a new way of fixing the gauge to (direct) maximal center gauge in\nSU(N) Yang-Mills theory and apply this method to SU(3) configurations which are\nvortex-like. We study the structure of the Z_3 configurations obtained after\ncenter-projecting the SU(3) ones.",
        "positive": "High Temperature QCD: I review recent results on QCD at high temperature on a lattice. Steady\nprogress with staggered fermions and Wilson type fermions allow a quantitative\ndescription of hot QCD whose accuracy in many cases parallels that of zero\ntemperature studies. Simulations with chiral quarks are coming of age, and\ntogheter with theoretical developments trigger interesting developments in the\nanalysis of the critical region. Issues related with the universality class of\nthe chiral transition and the fate of the axial symmetry are discussed in the\nlight of new numerical and analytical results. Transport coefficients and\nanalysis of bottomonium spectra compare well with results of heavy ion\ncollisions at RHIC and LHC. Model field theories, lattice simulations and high\ntemperature systematic expansions help building a coherent picture of the high\ntemperature phase of QCD. The (strongly coupled) Quark Gluon Plasma is heavily\ninvestigated, and asserts its role as an inspiring theoretical laboratory."
    },
    {
        "anchor": "Resonance study of SU(2) model with 2 fundamental flavours of fermions: Composite Higgs models are promising candidate models to address the\nlong-standing naturalness problem in the Standard Model. Among them, the most\nminimal one is the SU(2) with 2 flavours of fermions in the fundamental\nrepresentation of the gauge group. An important prediction in these models is\nthe existence of resonance spectrum in vector boson scattering. Here we study\nthe lowest such resonance, which is the equivalent of rho resonance in QCD. We\ndescribe the scan of the parameter space using the clover-improved Wilson\nfermions with Symanzik improved gauge action and then show the first results\nfor the mass and width of the rho resonance in this model.",
        "positive": "$B_7$, $B_8$ and chiral Ward identities: We present recent progress in understanding weak matrix elements on the\nlattice. We use HYP staggered fermions in quenched QCD to study numerically\nvarious properties of the $K^+\\to\\pi^+$ amplitudes of the electroweak penguin\noperators $Q_7$ and $Q_8$. We check chiral Ward identities to probe the\nvalidity of using improved staggered fermions in the calculation of weak matrix\nelements. We address the issue of mixing with unphysical lower dimension\noperators, which causes a divergent term in the case of the $\\Delta I = 1/2$\namplitudes. We propose a particular subtraction method as the best choice. We\nalso measure the gold-plated ratio $R$ originally suggested by Becirevic and\nVilladoro."
    },
    {
        "anchor": "Effects of finite volume on the $K_L$-$K_S$ mass difference: Phenomena that involve two or more on-shell particles are particularly\nsensitive to the effects of finite volume and require special treatment when\ncomputed using lattice QCD. In this paper we generalize the results of\nL\\\"uscher, and Lellouch and L\\\"uscher, which determine the leading order\neffects of finite volume on the two-particle spectrum and two-particle decay\namplitudes to determine the finite-volume effects in the second order mixing of\nthe $K^0$ and $\\overline{K^0}$ states. We extend the methods of Kim, Sachrajda\nand Sharpe to provide a direct, uniform treatment of these three, related,\nfinite-volume corrections. In particular, the leading, finite-volume\ncorrections to the $K_L$-$K_S$ mass difference $\\Delta M_K$ and the CP\nviolating parameter $\\epsilon_K$ are determined, including the potentially\nlarge effects which can arise from the near degeneracy of the kaon mass and the\nenergy of a finite-volume, two-pion state.",
        "positive": "Backpropagating Hybrid Monte Carlo algorithm for fast Lefschetz thimble\n  calculations: The Picard-Lefschetz theory has been attracting much attention as a tool to\nevaluate a multi-variable integral with a complex weight, which appears in\nvarious important problems in theoretical physics. The idea is to deform the\nintegration contour based on Cauchy's theorem using the so-called gradient flow\nequation. In this paper, we propose a fast Hybrid Monte Carlo algorithm for\nevaluating the integral, where we \"backpropagate\" the force of the fictitious\nHamilton dynamics on the deformed contour to that on the original contour,\nthereby reducing the required computational cost by a factor of the system\nsize. Our algorithm can be readily extended to the case in which one integrates\nover the flow time in order to solve not only the sign problem but also the\nergodicity problem that occurs when there are more than one thimbles\ncontributing to the integral. This enables, in particular, efficient\nidentification of all the dominant saddle points and the associated thimbles.\nWe test our algorithm by calculating the real-time evolution of the wave\nfunction using the path integral formalism."
    },
    {
        "anchor": "New algorithm for gauge fixing in SU(2) lattice gauge theory: An overrelaxed variant of simulated annealing is applied to the problem of\nmaximally abelian gauge fixing. The superiority of this algorithm over the\ncommonly used relaxation procedure is demonstrated. Biases on non gauge\ninvariant quantities due to gauge fixing ambiguities are discussed.",
        "positive": "Ginsparg-Wilson Formulation of 2D N =(2,2) SQCD with Exact Lattice\n  Supersymmetry: In this paper, we introduce the overlap Dirac operator, which satisfies the\nGinsparg-Wilson relation, to the matter sector of two-dimensional N=(2,2)\nlattice supersymmetric QCD (SQCD) with preserving one of the supercharges. It\nrealizes the exact chiral flavor symmetry on the lattice, to make possible to\ndefine the lattice action for general number of the flavors of fundamental and\nanti-fundamental matter multiplets and for general twisted masses. Furthermore,\nsuperpotential terms can be introduced with exact holomorphic or\nanti-holomorphic structure on the lattice. We also consider the lattice\nformulation of matter multiplets charged only under the central U(1) (the\noverall U(1)) of the gauge group G=U(N), and then construct lattice models for\ngauged linear sigma models with exactly preserving one supercharge and their\nchiral flavor symmetry."
    },
    {
        "anchor": "Non-Perturbative Renormalization in Lattice Field Theory: Non-perturbative renormalization of lattice composite operators plays a\ncrucial role in many applications of lattice field theory. We sketch the\ngeneral problems involved in this task and the methods which are currently used\nto cope with them. We present a detailed investigation of a new approach based\non the operator product expansion. We test the new method on the\ntwo-dimensional O(3) sigma-model and discuss its advantages and limitations.\nPh.D. thesis at Scuola Normale Superiore, Pisa, Italy.",
        "positive": "Lattice QCD Anatomy via the Energy-Momentum Component of Gluons: In this thesis, we perform the lattice QCD analysis via the energy-momentum\ncomponent of gluons. By introducing the momentum cutoff to the link variable,\nwe investigate which energy-momentum components of gluons induce each QCD\nphenomenon. We use the Landau gauge for the most part of the lattice QCD\nanalysis. In lattice QCD, we analyze color confinement, spontaneous chiral\nsymmetry breaking, topological charge, and the related topics. We also discuss\nseveral comparisons with effective theories. As for color confinement, we\ncalculate the quark-antiquark potential, the color flux tube, and meson masses.\nFrom quantitative analysis, we find that color confinement is induced by the\nlow-momentum component below 1.5 GeV. As for spontaneous chiral symmetry\nbreaking, we calculate the chiral condensate and the Dirac spectrum.\nSpontaneous chiral symmetry breaking is induced by the broad low-momentum\ncomponent which ranges even above 1.5 GeV. The present result suggests that\ncolor confinement and spontaneous chiral symmetry breaking are induced by\nsomehow different energy-momentum components of gluons. As for topological\ncharge, we calculate the topological charge density and the Dirac zero mode.\nTopological charge is induced by the broad energy-momentum component, which is\nsimilar to spontaneous chiral symmetry breaking."
    },
    {
        "anchor": "Dynamical Simulations with Smeared Link Staggered Fermions: One of the most serious problems of the staggered fermion lattice action is\nflavor symmetry violation. Smeared link staggered fermions can improve flavor\nsymmetry by an order of magnitude relative to the standard thin link action.\nOver the last few years different smearing transformations have been proposed,\nboth with perturbatively and non-perturbatively determined coefficients. What\nhindered the acceptance and more general use of smeared link fermions until now\nis the relative difficulty of dynamical simulations and the lack of\nperturbative calculations with these actions. In both areas there have been\nsignificant improvement lately, that I will review in this paper.",
        "positive": "The Roberge-Weiss endpoint in N_f = 2 QCD: We present the results of extensive simulations regarding the critical\nbehavior at the endpoint of the Roberge-Weiss transition for N_f = 2 QCD. We\nconfirm early evidence, presented in arXiv:0909.0254, according to which the\nRoberge-Weiss endpoint is first order in the limit of large or small quark\nmasses, and second order for intermediate masses. A systematic study of the\ntransition strength as a function of the quark mass in the first order regions,\npermits us to estimate the tricritical values of the quark mass separating the\nsecond order region from the first order ones."
    },
    {
        "anchor": "The running of the bare coupling in SU(N) gauge theories: For N>4 there is a first order bulk transition that cleanly separates the\nstrong and weak coupling regimes of SU(N) lattice gauge theories with the\nplaquette action. We find that in this case the calculated string tension can\nbe readily fitted throughout the weak coupling region by a standard 3-loop\nperturbative expression modified by lattice spacing corrections of the expected\nform. While our fits demand the presence of the latter, they are not\nconstraining enough to tell us which of the various bare coupling schemes is a\n`good' one, in the sense that terms in the beta-function beyond 3-loops are\nindeed negligible (in the relevant range of scales). To resolve this ambiguity\nwe work in SU(3), using the Schrodinger Functional coupling scheme as a\nbenchmark, and find that the Parisi mean-field improved coupling scheme matches\nit very well. Using the latter scheme, we have fitted the values of the string\ntension that have been calculated for SU(3) to SU(8), to obtain\nLambda_MSbar/sqrt(sigma) = 0.503(2)(40) + 0.33(3)(3)/N**2, where the first\nerror is statistical and the second is our estimate of the systematic error\nfrom all sources.",
        "positive": "A meron cluster solution for the sign problem of the two-dimensional\n  O(3) model: The two-dimensional O(3) model at a vacuum angle theta=pi is investigated.\nThis model has a severe sign problem. By a Wolff cluster algorithm an integer\nor half-integer topological charge is assigned to each cluster. The meron\nclusters (clusters with half-integer topological charge) are used to construct\nan improved estimator for the correlation function of two spins at theta=pi.\nOnly configurations with 0 and 2 merons contribute to this correlation\nfunction.\n  An algorithm, that generates configurations with only 0 and 2 merons, is\nconstructed and numerical simulations at theta=pi are performed.\n  The numerical results indicate the presence of long range correlations at\ntheta=pi."
    },
    {
        "anchor": "Using Approximating Polynomials in Partial-Global Dynamical Simulations: Smeared link fermionic actions can be straightforwardly simulated with\npartial-global updating. The efficiency of this simulation is greatly increased\nif the fermionic matrix is written as a product of several near-identical\nterms. Such a break-up can be achieved using polynomial approximations for the\nfermionic matrix. In this paper we will focus on methods of determining the\noptimum polynomials.",
        "positive": "A QUDA-branch to compute disconnected diagrams in GPUs: Although QUDA allows for an efficient computation of many QCD quantities, it\nis surprinsingly lacking tools to evaluate disconnected diagrams, for which\nGPUs are specially well suited. We aim to fill this gap by creating our own\nbranch of QUDA, which includes new kernels and functions required to calculate\nfermion loops using several methods and fermionic regularizations."
    },
    {
        "anchor": "The Schroedinger functional coupling in quenched QCD at low energies: Existing non-perturbative computations of the running coupling of quenched\nQCD in the Schroedinger functional scheme are extended to scales mu lying much\ndeeper in the low-energy regime. We are able to reach 1/mu ~ 0.9 fm, where a\nsignificant deviation from its perturbative evolution is observed.",
        "positive": "Nucleon form factors from high statistics mixed-action calculations with\n  2+1 flavors: We present new high-statistics results for nucleon form factors at pion\nmasses of approximately 290, 350, 500, and 600 MeV using a mixed action of\ndomain wall valence quarks on an improved staggered sea. We perform chiral fits\nto both vector and axial form factors and compare our results to experiment."
    },
    {
        "anchor": "Thermodynamics of Lattice QCD with 2 Light Dynamical (Staggered) Quark\n  Flavours on a $16^3\\times 8$ Lattice: Lattice QCD with 2 light staggered quark flavours is being simulated on a\n$16^3\\times8$ lattice to study the transition from hadronic matter to a quark\ngluon plasma. We have completed runs at $m_q=0.0125$ and are extending this to\n$m_q=0.00625$. We also examine the addition of a non-dynamical \"strange\" quark.\nThermodynamic order parameters are being measured across the transition and\nfurther into the plasma phase, as are various screening lengths. No evidence\nfor a first order transition is seen, and we estimate the transition\ntemperature to be $TY_c=143(7) MeV$.",
        "positive": "Strange quark mass and Lambda parameter by the ALPHA collaboration: We determine f_K for lattice QCD in the two flavor approximation with\nnon-perturbatively improved Wilson fermions. The result is used to set the\nscale for dimensionful quantities in CLS/ALPHA simulations. To control its\ndependence on the light quark mass, two different strategies for the chiral\nextrapolation are applied. Combining f_K and the bare strange quark mass with\nnon-perturbative renormalization factors and step scaling functions computed in\nthe Schroedinger Functional, we determine the RGI strange quark mass and the\nLambda parameter in units of f_K."
    },
    {
        "anchor": "Towards Lattice QCD Baryon Forces at the Physical Point: First Results: Lattice QCD calculations of baryon forces are performed for the first time\nwith (almost) physical quark masses. $N_f = 2+1$ dynamical clover fermion gauge\nconfigurations are generated at the lattice spacing of $a \\simeq 0.085$ fm on a\n$(96 a)^4 \\simeq (8.2 {\\rm fm})^4$ lattice with quark masses corresponding to\n$(m_\\pi, m_K) \\simeq (146, 525)$ MeV. Baryon forces are calculated using the\ntime-dependent HAL QCD method. In this report, we study $\\Xi\\Xi$ and $NN$\nsystems both in $^1S_0$ and $^3S_1$-$^3D_1$ channels, and the results for the\ncentral and tensor forces as well as phase shifts in the $\\Xi\\Xi$ $(^1S_0)$\nchannel are presented.",
        "positive": "Gluon Propagator in the Infrared Region: The gluon propagator is calculated in quenched QCD for two different lattice\nsizes (16^3x48 and 32^3x64) at beta=6.0. The volume dependence of the\npropagator in Landau gauge is studied. The smaller lattice is instrumental in\nrevealing finite volume and anisotropic lattice artefacts. Methods for\nminimising these artefacts are developed and applied to the larger lattice\ndata. New structure seen in the infrared region survives these conservative\ncuts to the lattice data. This structure serves to rule out a number of models\nthat have appeared in the literature. A fit to a simple analytical form\ncapturing the momentum dependence of the nonperturbative gluon propagator is\nalso reported."
    },
    {
        "anchor": "Finite-Size Scaling on the Ising Coexistence Line: We report tests of finite-size scaling ansatzes in the low temperature phase\nof the two-dimensional Ising model. For moments of the magnetisation density,\nwe find good agreement with the new ansatz of Borgs and Koteck\\'y, and clear\nevi consequences of the convexity of the free energy are not adequately treated\nin either of these approaches.\\lb {\\it Keywords}\\/: Finite-size scaling, 2-d\nIsing, pure-phase susceptibility.",
        "positive": "$B_s\u03c0^+$ scattering and search for X(5568) with lattice QCD: We investigate $B_s\\pi^+$ scattering in s-wave using lattice QCD in order to\nsearch for an exotic resonance X(5568) with flavor $\\bar b s \\bar d u$; such a\nstate was recently reported by D0 but was not seen by LHCb. If X(5568) with\n$J^P=0^+$ exists, it can strongly decay only to $B_s\\pi^+$ and lies\nsignificantly below all other thresholds, which makes a lattice search for\nX(5568) cleaner and simpler than for other exotic candidates. Both an elastic\nresonance in $B_s\\pi^+$ as well as a deeply bound $B^+\\bar K^0$ would lead to\ndistinct signatures in the energies of lattice eigenstates, which are not seen\nin our simulation. We therefore do not find a candidate for X(5568) with\n$J^P=0^+$ in agreement with the recent LHCb result. The extracted $B_s\\pi^+$\nscattering length is compatible with zero within the error."
    },
    {
        "anchor": "Spectral density of the Dirac-Ginsparg-Wilson operator, chiral $U(1)_A$\n  anomaly, and analyticity in the high temperature phase of $QCD$: Using general properties of the $Q=0$ topological sector we previously argued\nthat a vector-like theory, with chiral $U(1)_A$ anomaly, and exact non-Abelian\nchiral symmetry, should exhibit divergent susceptibilities in the chiral limit,\nthe two-flavor Schwinger model being a paradigmatic example of the realization\nof this scenario. Two flavor $QCD$ at $T>T_c$ satisfies all the above\nconditions, and it is also expected that the $U(1)_A$ axial symmetry remains\neffectively broken in its high temperature phase. Therefore we would expect a\nnon-analyticity in the quark mass dependence of the free energy density, in\ncontrast with the Dilute Instanton Gas Approximation (DIGA) prediction. We\ninvestigate in this work whether the aforementioned results can also be\nreproduced making only use of standard properties of the spectral density of\nthe Dirac operator, without having to resort to general properties of the $Q=0$\ntopological sector. We show that the only way to derive a non-trivial\n$\\theta$-dependence, and an analytical free energy density in $QCD$ with two\ndegenerate flavors is that the spectral density, $\\rho\\left(\\lambda,m\\right)$,\nof the absolute value of the non-zero modes of the Dirac-Ginsparg-Wilson\noperator develops a $m^2\\delta(\\lambda)$ function in the thermodynamic limit.\nThis is the expected result in the DIGA, where interactions between instantons\nin the dilute gas are fully neglected. However, at temperatures close to $T_c$\nthe interaction between instantons should become non-negligible, and the\nsplitting from zero of the near-zero modes, which has been neglected in the\nDIGA, should be taken into account. Therefore we expect that the\n$m^2\\delta(\\lambda)$ contribution to the spectral density is no longer correct\nat these temperatures, and that the free energy density becomes a non-analytic\nfunction of the quark mass.some clarifications added",
        "positive": "Z_2 Monopoles and Deconfinement Phase Transition in SU(2) Lattice Gauge\n  Theory: The paper has been withdrawn"
    },
    {
        "anchor": "$B$ Meson Matrix Elements from Various Heavy Quark Effective Theories: Various properties of heavy-light mesons are determined, including decay\nconstants, the $B_{B}$-parameter, and the Isgur-Wise function. The heavy\n(bottom) quark is simulated with the static, NRQCD and/or (fixed-velocity)\nlattice-HQET effective theories, using optimally-smeared sources as produced by\nthe ``Maximal Operator Smearing Technique''.",
        "positive": "I=2 Pion Scattering Length with Wilson Fermions: We present results for I=2 pion scattering length with the Wilson fermions in\nthe quenched approximation. The finite size method presented by L\\\"uscher is\nemployed, and calculations are carried out at $\\beta=5.9$, 6.1, and 6.3. In the\ncontinuum limit, we obtain a result in reasonable agreement with the\nexperimental value."
    },
    {
        "anchor": "$\\mathcal{N}=1$ Super-Yang-Mills theory on the lattice with twisted mass\n  fermions: Super-Yang-Mills theory (SYM) is a central building block for supersymmetric\nextensions of the Standard Model of particle physics. Whereas the weakly\ncoupled subsector of the latter can be treated within a perturbative setting,\nthe strongly coupled subsector must be dealt with a non-perturbative approach.\nSuch an approach is provided by the lattice formulation. Unfortunately a\nlattice regularization breaks supersymmetry and consequently the mass\ndegeneracy within a supermultiplet. In this article we investigate the\nproperties of $\\mathcal{N}=1$ supersymmetric SU(3) Yang-Mills theory with a\nlattice Wilson Dirac operator with an additional parity mass, similar as in\ntwisted mass lattice QCD. We show that a special $45^\\circ$ twist effectively\nmoves the mass splitting of the chiral partners. Thus, at finite lattice\nspacing both chiral and supersymmetry are enhanced resulting in an improved\ncontinuum extrapolation. Furthermore, we show that for the non-interacting\ntheory at $45^\\circ$ twist discretization errors of order $\\mathcal{O}(a)$ are\nsuppressed, suggesting that the same happens for the interacting theory as\nwell. As an aside, we demonstrate that the DD$\\alpha$AMG multigrid algorithm\naccelerates the inversion of the Wilson Dirac operator considerably. On a\n$16^3\\times 32$ lattice, speed-up factors of up to 20 are reached if commonly\nused algorithms are replaced by the DD$\\alpha$AMG.",
        "positive": "Vortex-Line Percolation in the Three-Dimensional Complex Ginzburg-Landau\n  Model: We study the phase transition of the three-dimensional complex |psi|^4 theory\nby considering the geometrically defined vortex-loop network as well as the\nmagnetic properties of the system in the vicinity of the critical point. Using\nhigh-precision Monte Carlo techniques we examine an alternative formulation of\nthe geometrical excitations in relation to the global O(2)-symmetry breaking,\nand check if both of them exhibit the same critical behavior leading to the\nsame critical exponents and therefore to a consistent description of the phase\ntransition. Different percolation observables are taken into account and\ncompared with each other. We find that different definitions of constructing\nthe vortex-loop network lead to different results in the thermodynamic limit,\nand the percolation thresholds do not coincide with the thermodynamic phase\ntransition point."
    },
    {
        "anchor": "Hidden charm molecules in finite volume: In the present paper we address the interaction of pairs of charmed mesons\nwith hidden charm in a finite box. We use the interaction from a recent model\nbased on heavy quark spin symmetry that predicts molecules of hidden charm in\nthe infinite volume. The energy levels in the box are generated within this\nmodel, and from them some synthetic data are generated. These data are then\nemployed to study the inverse problem of getting the energies of the bound\nstates and phase shifts for $D \\bar D$ or $D^* {\\bar D}^*$. Different\nstrategies are investigated using the lowest two levels for different values of\nthe box size, carrying a study of the errors produced. Starting from the upper\nlevel, fits to the synthetic data are carried out to determine the scattering\nlength and effective range plus the binding energy of the ground state. A\nsimilar strategy using the effective range formula is considered with a\nsimultaneous fit to the two levels, one above and the other one below\nthreshold. This method turns out to be more efficient than the other one.\nFinally, a method based on the fit to the data by means of a potential and a\nloop function conveniently regularized, turns out to be very efficient and\nallows to produce accurate results in the infinite volume starting from levels\nof the box with errors far larger than the uncertainties obtained in the final\nresults. A regularization method based on Gaussian wave functions turns out to\nbe rather efficient in the analysis and as a byproduct a practical and fast\nmethod to calculate the L\\\"uscher function with high precision is presented.",
        "positive": "The basics and applications of the tempered Lefschetz thimble method for\n  the numerical sign problem: The numerical sign problem has long been a major obstacle to first-principles\ncalculations in various important fields of physics. We report that the\nrecently proposed algorithm, tempered Lefschetz thimble method (TLTM), and its\nworldvolume extension (WV-TLTM) can be a promising solution in its trustability\nand versatility."
    },
    {
        "anchor": "HQET Flavor Currents Using Automated Lattice Perturbation Theory: Matrix elements of heavy-light flavor currents play an important role in\nmodern particle physics and precise theory predictions are of interest for\nphenomenology. Heavy Quark Effective Theory (HQET) is a valuable tool to obtain\nsuch predictions. In the HQET matching program of the ALPHA collaboration\npresently only the temporal component of the axial vector current is included.\nExtending the matching to the temporal component of the vector current and the\nspatial components of the axial vector current thus seems desirable. Here we\npresent a recent one-loop study in lattice perturbation theory to test two\ncandidate matching observables for these currents for their quality to guide\nfuture non-perturbative investigations.",
        "positive": "Effects of a potential fourth fermion generation on the upper and lower\n  Higgs boson mass bounds: We study the effect of a potential fourth fermion generation on the upper and\nlower Higgs boson mass bounds. This investigation is based on the numerical\nevaluation of a chirally invariant lattice Higgs-Yukawa model emulating the\nsame Higgs-fermion coupling structure as in the Higgs sector of the electroweak\nStandard Model. In particular, the considered model obeys a Ginsparg-Wilson\nversion of the underlying ${SU}(2)_L\\times {U}(1)_Y$ symmetry, being a global\nsymmetry here due to the neglection of gauge fields in this model. We present\nour results on the modification of the upper and lower Higgs boson mass bounds\ninduced by the presence of a hypothetical very heavy fourth quark doublet.\nFinally, we compare these findings to the standard scenario of three fermion\ngenerations."
    },
    {
        "anchor": "Quantum Mechanics \u00e0 la Langevin and Supersymmetry: We study quantum mechanics in the stochastic formulation, using the\nfunctional integral approach. The noise term enters the classical action as a\nlocal contribution of anticommuting fields. The partition function is not\ninvariant under ${\\mathcal N}=1$ SUSY, but can be obtained from a, manifestly,\nsupersymmetric expression, upon fixing a local fermionic symmetry, called\n$\\kappa-$symmetry. The kinetic term for the fermions is a total derivative and\ncan contribute only on the boundaries. We define combinations that scale\nappropriately, as the lattice spacing is taken to zero and the lattice size to\ninfinity and provide evidence, by numerical simulations, that the correlation\nfunctions of the auxiliary field do satisfy Wick's theorem. We show, in\nparticular, that simulations can be carried out using a purely bosonic action.\n  The physical import is that the classical trajectory, $\\phi(\\tau)$, becomes a\n(chiral) superfield, $(\\phi(\\tau),\\psi_{\\alpha}(\\tau),F(\\tau))$, when quantum\nfluctuations are taken into account.",
        "positive": "Zemach radius of the proton from lattice QCD: We present the first lattice-QCD result for the Zemach radius of the proton.\nOur calculation includes both quark-connected and -disconnected diagrams and\nassesses all sources of systematic uncertainties arising from excited-state\ncontributions, finite-volume effects and the continuum extrapolation. At the\nphysical point, we obtain $r_Z^p = ( 1.013 \\pm 0.010\\ (\\mathrm{stat}) \\pm\n0.012\\ (\\mathrm{syst}) )~\\mathrm{fm}$, which suggests a small value of the\nZemach radius, but is compatible with most of the experimental studies."
    },
    {
        "anchor": "Exact finite-size scaling with corrections in the two-dimensional Ising\n  model with special boundary conditions: The two-dimensional Ising model with Brascamp-Kunz boundary conditions has a\npartition function more amenable to analysis than its counterpart on a torus.\nThis fact is exploited to exactly determine the full finite-size scaling\nbehaviour of the Fisher zeroes of the model. Moreover, exact results are also\ndetermined for the scaling of the specific heat at criticality, for the\nspecific-heat peak and for the pseudocritical points. All corrections to\nscaling are found to be analytic and the shift exponent $\\lambda$ does not\ncoincide with the inverse of the correlation length exponent $1/\\nu$.",
        "positive": "Ginsparg-Wilson Relation and Spin Chains: The Baxter 8-vertex model is equivalent to a particular lattice formulation\nof a self-interacting, massive Dirac fermion theory. In the time-continuum\nlimit, the lattice Hamiltonian (XYZ spin chain) can be explicitly transformed\nto a lattice Dirac Hamiltonian. We show that the kernel describing the\nquadratic part of this Hamiltonian satisfies a one-dimensional version of the\nGinsparg-Wilson relation. The corresponding conserved charge is derived and\ncompared with the conserved arrow number of the 8-vertex model."
    },
    {
        "anchor": "SU(3) gauge invariant lattice QCD exploration of the dual superconductor\n  picture in flux tube fusion, in the dual gluon mass, and in the dual\n  Ginzburg-Landau parameters: The colour fields, created by a static gluon-quark-antiquark system, are\ncomputed in quenched SU(3) lattice QCD, in a $24^3\\times 48$ lattice at\n$\\beta=6.2$ and $a=0.07261(85)\\,fm$. We compute the hybrid Wilson Loop\nincluding the cases when the gluon and the antiquark are superposed, i. e., the\nquark-antiquark case and when the quark and antiquark are superposed, i. e.,\nthe gluon-gluon case. The Casimir scaling is investigated, in the two gluon\nglueball case the Casimir scaling is consistent with the formation of an\nadjoint string. Measuring the decay of the tail in the mid section of the flux\ntube for the two gluon glueball and for the quark-antiquark meson, we determine\nthe penetration length and present a gauge invariant effective dual gluon mass\nof $0.905\\pm0.163\\,\\text{GeV}$. We also try to determine the coherence length\ncomparing our results with the dual Ginzburg-Landau approach. With the\npenetration length and the possible coherence length we determine a putative\nGinzburg-Landau dimensionless parameter, which is possibly consistent with a\ntype II superconductor picture. These results are obtained at fixed\nquark-antiquark distance of 0.58 fm.",
        "positive": "Quark Confinement and the Renormalization Group: Recent approaches to quark confinement are reviewed, with an emphasis on\ntheir connection to renormalization group methods. Basic concepts related to\nconfinement are introduced: the string tension, Wilson loops and Polyakov\nlines, string breaking, string tension scaling laws, center symmetry breaking,\nand the deconfinement transition at non-zero temperature. Current topics\ndiscussed include confinement on $R^3\\times S^1$, the real-space\nrenormalization group, the functional renormalization group, and the\nSchwinger-Dyson equation approach to confinement."
    },
    {
        "anchor": "Non-Relativistic QCD for Heavy Quark Systems: We employ a nonrelativistic version of QCD (NRQCD) to study heavy\nquark-antiquark bound states in the lowest approximation without fine\nstructure. We use gluon configurations on a 16^3 by 48 lattice at beta=6.2 from\nthe UKQCD collaboration. For quark masses in the vicinity of the b we obtain\nbound state masses for S, P and both types of D wave. We also detect signals\nfor two types of hybrids (quark,antiquark,gluon states). The results are\nsufficiently accurate to confirm that the values of the D wave mass from both\nlattice D waves coincide indicating that the cubical invariance of the lattice\nis restored to full rotational invariance at large distance.\n  Our results also show that the S-P splitting is indeed insensitive to\nvariations in the bare quark mass from Ma=1.0 to Ma=1.9.",
        "positive": "Modeling few-body resonances in finite volume: Under the assumption of separable interactions, we illustrate how the\nfew-body quantization condition may be formulated in terms of phase shifts in\ngeneral, which may be useful for describing and modeling of few-body resonances\nin finite volume."
    },
    {
        "anchor": "Contents of Lattice 2000 Proceedings: We give here a compilation of papers presented at Lattice 2000 (XVIII Intl.\nSymposium on Lattice Field Theory, Bangalore, India, 17-22 August 2000). The\ntable of contents provides links to papers on the e-print arXiv.",
        "positive": "Weyl and ghost fermions on the lattice: Nielsen-Ninomiya theorem forbids Weyl fermions on the lattice which respect\nthe full hypercubic symmetry. By giving up this assumption in a specific way,\nit is possible to formulate a lattice theory with a single Weyl fermion in four\ndimensions and a sextet of Dirac particles in two dimensions. This way, the\nmeaning of the theorem in relation to the doubling problem on the lattice is\nclarified. Whether the proposal will be suited for future lattice computations\nwill depend on the effects the extra particles will have in the interacting\ntheory."
    },
    {
        "anchor": "Susceptibilities, the Specific Heat and a Cumulant in Two-Flavour QCD: We study the quark mass dependence of various response functions, which\ncontribute to chiral susceptibilities and the specific heat in the staggered\nfermion formulation of two-flavour QCD. This yields information about the\ncritical exponents $\\alpha$, $\\beta$ and $\\delta$. In the case of the chiral\nsusceptibility, obtained as derivative of the chiral order parameter with\nrespect to the quark mass, we calculate all contributions. This allows to\nconstruct a cumulant of the order parameter, which is a scaling function and\nyields a direct determination of the critical exponent $\\delta$. All our\nresults are consistent with a second order phase transition.",
        "positive": "Application of tensor network method to two dimensional lattice\n  $\\mathcal{N}=1$ Wess-Zumino model: We study a tensor network formulation of the two dimensional lattice\n$\\mathcal{N}=1$ Wess-Zumino model with Wilson derivatives for both fermions and\nbosons. The tensor renormalization group allows us to compute the partition\nfunction without the sign problem, and basic ideas to obtain a tensor network\nfor both fermion and scalar boson systems were already given in previous works.\nIn addition to improving the methods, we have constructed a tensor network\nrepresentation of the model including the Yukawa-type interaction of Majorana\nfermions and real scalar bosons. We present some numerical results."
    },
    {
        "anchor": "Quenched QCD at finite temperature with overlap Fermions: We study quenched QCD just above the phase transition temperature using\noverlap Fermions. Exact zero modes of the overlap operator are localized.\nChiral symmetry is restored, as indicated by the behavior of the chiral\ncondensate after subtracting the effects of zero modes. The vector and\npseudo-scalar screening masses are close to ideal gas values.",
        "positive": "Critical Equalities for Potts Models: We apply a simple analytical criterion for locating critical temperatures to\nPotts models on square and triangular lattices. In the self-dual case, i.e. on\nthe square lattice we reproduce known exact values of the critical temperature\nand derive the internal energy of the model at the critical point. For the\nPotts model on the triangular lattice we obtain very good numerical estimate of\nthe critical temperature and also of the internal energy at the critical point."
    },
    {
        "anchor": "Efficient solution of the multi-channel L\u00fcscher determinant condition\n  through eigenvalue decomposition: We present a method for efficiently finding solutions of L\\\"uscher's\nquantisation condition, the equation which relates two-particle scattering\namplitudes to the discrete spectrum of states in a periodic spatial volume of\nfinite extent such as that present in lattice QCD. The approach proposed is\nbased on an eigenvalue decomposition in the space of coupled-channels and\npartial-waves, which proves to have several desirable and simplifying features\nthat are of great benefit when considering problems beyond simple elastic\nscattering of spinless particles. We illustrate the method with a toy model of\nvector-vector scattering featuring a high density of solutions, and with an\napplication to explicit lattice QCD energy level data describing $J^P=1^-$ and\n$1^+$ scattering in several coupled channels.",
        "positive": "Long range correlations in branched polymers: We study the correlation functions in the branched polymer model. Although\nthere are no correlations in the grand canonical ensemble, when looking at the\ncanonical ensemble we find negative long range power like correlations. We\npropose that a similar mechanism explains the shape of recently measured\ncorrelation functions in the elongated phase of 4d simplicial gravity."
    },
    {
        "anchor": "1+1+1 flavor QCD+QED simulation at the physical point: We present our progress report on 1+1+1 flavor QCD+QED simulation at the\nphysical point. Calculations are carried out with 2+1 flavor QCD gauge\nconfigurations generated by the PACS-CS Collaboration. The dynamical QED effect\nand the up-down quark mass difference are incorporated by the reweighting\ntechnique. We also discuss some physics results.",
        "positive": "The determination of alpha_s from lattice QCD with 2+1 flavors of\n  dynamical quarks: We describe the first lattice determination of the strong coupling constant\nwith 3 flavors of dynamical quarks. The method follows previous analyses in\nusing a perturbative expansion for the plaquette and Upsilon spectroscopy to\nset the scale. Using dynamical configurations from the MILC collaboration with\n2+1 flavors of dynamical quarks we are able to avoid previous problems of\nhaving to extrapolate to 3 light flavors from 0 and 2. Our results agree with\nour previous work: alpha_s_MSbar(M_Z) = 0.121(3)."
    },
    {
        "anchor": "QCD and the eta prime Mass: Instantons or Confinement?: We argue that lattice calculations of the $\\eta'$ mass in QCD with $N_c=2$\ncolors performed at non-zero baryon chemical potential can be used to study the\nmechanism responsible for the mass of the $\\eta'$. QCD with two colors is an\nideal laboratory because it exhibits confinement, chiral symmetry breaking and\na would-be $U(1)_A$ Goldstone boson at all densities. Since the instanton\ndensity and the confinement scale vary with density in a very different way,\ninstantons are clearly distinguishable from other possible mechanisms. There is\nan instanton prediction for the $\\eta'$ mass at large density that can be\ncompared to lattice results. The density dependence of the instanton\ncontribution is a simple consequence of the integer topological charge carried\nby the instanton. We also argue that $N_c=3$ color QCD at finite isospin\ndensity can be used in order to study the origin of OZI-violation in the scalar\nsector.",
        "positive": "Transverse Structure of Nucleon Parton Distributions from Lattice QCD: This work presents the first calculation in lattice QCD of three moments of\nspin-averaged and spin-polarized generalized parton distributions in the\nproton. It is shown that the slope of the associated generalized form factors\ndecreases significantly as the moment increases, indicating that the transverse\nsize of the light-cone quark distribution decreases as the momentum fraction of\nthe struck parton increases."
    },
    {
        "anchor": "Meson screening mass at finite chemical potential: Knowledge of the screening masses at finite chemical potential can provide\ninsight into the nature of the QCD phase diagram. However, lattice studies at\nfinite chemical potential suffer from the well-known issue of the sign problem,\nwhich has made the calculation of observables such as screening correlators and\nscreening masses at finite chemical potential quite challenging. One way to\nproceed is by expanding the observable in a Taylor series in the chemical\npotential and hence calculating the finite-density corrections to the\nobservable. In this talk, we will use this approach to calculate the screening\nmass of the pseudoscalar meson at finite temperatures and chemical potential by\nexpanding the screening correlator in a Taylor series in the chemical\npotential. We will present our results for the second derivative of the\nscreening mass w.r.t. the chemical potential. Our calculation was done on $64^3\n\\times 8$ lattices generated using the (2+1) HISQ/tree action.",
        "positive": "Probing the finite temperature phase transition with Nf=2\n  nonperturbatively improved Wilson fermions: The critical temperature and the nature of the QCD finite temperature phase\ntransition are determined for Nf=2 dynamical flavors of nonperturbatively\nimproved Wilson fermions. The calculations are performed on large lattices with\ntemporal extents Nt=12, 10 and 8, and lattice spacings down to a = 0.075 fm. We\nfind the deconfinement and chiral phasetransitions to take place at the same\ntemperature. Our results are in broad agreement with a second order phase\ntransition in the chiral limit. The critical temperature at the physical quark\nmass is found to be Tc = 174(3)(6) MeV."
    },
    {
        "anchor": "Low-temperature expansion in link formulation. II: We extend our previous analysis to arbitrary two dimensional SU(N) principal\nchiral model in a link formulation. A general expression for the second order\ncoefficient of fixed distance correlation function is given in terms of Green\nfunctions. This coefficient is calculated for distance 1 and is proven to be\npath independent. We also study the weak coupling expansion of the free energy\nof one dimensional SU(N) model and explain why it is non-uniform in the volume.\nFurther, we investigate the contribution of holonomy operators to the\nlow-temperature expansion in two dimensions. All our results agree with the\nconventional expansion. Nevertheless, we give some example which indicates that\nthe expansion in the link formulation can also suffer from ambiguities\npreviously found in the conventional perturbation theory.",
        "positive": "Axial vector current of exact chiral symmetry on the lattice: We discuss the exact chiral symmetry and its spontaneous breakdown in lattice\nQCD with the Dirac operators satisfying the Ginsparg-Wilson relation. The axial\nvector current, which turns out to be related to the vector current simply by\nthe insertion of the operator \\gamma_5 (1-aD), is explicitly constructed in the\ncase of the Neuberger-Dirac operator. We also consider an Euclidean proof of\nthe Nambu-Goldstone theorem using the Ward-Takahashi identity of this symmetry."
    },
    {
        "anchor": "Fate of the conformal fixed point with twelve massless fermions and\n  SU(3) gauge group: We report new results on the conformal properties of an important strongly\ncoupled gauge theory, a building block of composite Higgs models beyond the\nStandard Model. With twelve massless fermions in the fundamental representation\nof the SU(3) color gauge group, an infrared fixed point of the $\\beta$-function\nwas recently reported in the theory (Cheng:2014jba) with uncertainty in the\nlocation of the critical gauge coupling inside the narrow $[ 6.0<g_*^2<6.4]$\ninterval and widely accepted since as the strongest evidence for a conformal\nfixed point and scale invariance in the theory with model-building\nimplications. Using the exact same renormalization scheme as the previous\nstudy, we show that no fixed point of the $\\beta$-function exists in the\nreported interval. Our findings eliminate the only seemingly credible evidence\nfor conformal fixed point and scale invariance in the $N_f=12$ model whose\ninfrared properties remain unresolved. The implications of the recently\ncompleted 5-loop QCD beta function for arbitrary flavor number are discussed\nwith respect to our work.",
        "positive": "Kaon Mixing Beyond the SM from Nf=2 tmQCD and model independent\n  constraints from the UTA: We present the first unquenched, continuum limit, lattice QCD results for the\nmatrix elements of the operators describing neutral kaon oscillations in\nextensions of the Standard Model. Owing to the accuracy of our calculation on\n\\Delta S=2 weak Hamiltonian matrix elements, we are able to provide a refined\nUnitarity Triangle analysis improving the bounds coming from model independent\nconstraints on New Physics. In our non-perturbative computation we use a\ncombination of Nf=2 maximally twisted sea quarks and Osterwalder-Seiler valence\nquarks in order to achieve both O(a)-improvement and continuum-like\nrenormalization properties for the relevant four-fermion operators. The\ncalculation of the renormalization constants has been performed\nnon-perturbatively in the RI-MOM scheme. Based on simulations at four values of\nthe lattice spacing and a number of quark masses we have\nextrapolated/interpolated our results to the continuum limit and physical\nlight/strange quark masses."
    },
    {
        "anchor": "The Strangeness and Charmness of Nucleon from Overlap Fermions: The calculation of the strangeness and charmness of the nucleon is presented\nwith overlap fermion action on 2+1 flavor domain wall fermion configurations.\nWe adopt stochastic grid sources and the low mode substitution technique to\nimprove the signals of nucleon correlation functions and the loops. The\ncalculation is done on a $24^3\\times 64$ lattice with $m_l=0.005$, $m_h=0.04$,\nand $a^{-1}=1.73\\,{\\rm GeV}$. We find $ f_{T_{s}} = 0.048(15)$ and $f_{T_{c}} =\n0.029(43)$.",
        "positive": "QCD Monopoles and Chiral Symmetry Breaking on SU(2) Lattices: Pseudoscalar correlator is measured in a singular (monopole dominant) and a\nregular (photon dominant) parts of a maximal abelian field on SU(2) lattice. In\nthe abelian field and its singular part, light pseudoscalar boson are observed\nsimilar to that in SU(2) field. On the other hand , the correlator in the\nregular part behaves like a product of free quark and anti-quark. Obtained\nresults give a support for a possibility that monopole condensation is\nresponsible for chiral symmetry breaking as well as confinement. Correlation\nbetween monopoles and instantons is also investigated by observing topological\ncharge. A field including monopoles carrys topological charge with good\ncorrelation to that in original SU(2) gauge field while that including only\nphotons shows no topological charge."
    },
    {
        "anchor": "Exploring phase diagram of $N_f=3$ QCD at $\u03bc=0$ with HISQ fermions: We studied the QCD phase transition as a function of quark mass in the\n$N_f=3$ QCD at vanishing baryon density. Lattice simulations have been\nperformed using Highly Improved Staggered Quarks on $N_{\\tau}=6$ lattices with\nquark masses that correspond to pion masses in the region $80 \\lesssim m_{\\pi}\n\\lesssim 230 $MeV. We found no evidence of the first order phase transition in\nthe current pion mass window. The pion mass at the critical point where the\nfirst order phase transition starts is estimated to be $m^c_{\\pi}\\lesssim 45$\nMeV.",
        "positive": "Wilson--Yukawa Chiral Model on Lattice and Non-commutative Geometry: Based upon the mathematical formulas of Lattice gauge theory and\nnon-commutative geometry differential calculus, we developed an approach of\ngeneralized gauge theory on a product of the spacetime lattice and the two\ndiscrete points(or a $Z_2$ discrete group). We introduce a differentiation for\nnon-nearest-neighbour points and find that this differentiation may lead to the\nintroduction of Wilson term in the free fermion Lagrangian on lattice. The\nWilson-Yukawa chiral model on lattice is constructed by the generalized gauge\ntheory and a toy model and Smit-Swift model are studied."
    },
    {
        "anchor": "Lattice calculation of $D_s$ to $\u03b7^{(\\prime)}$ semi-leptonic decay\n  form factors: We report lattice results of $D_s$ meson semi-leptonic decay form factors to\n$\\eta$ and $\\eta'$ mesons. This decay process contains disconnected fermion\nloops, which are challenging in lattice calculations. Our result shows that the\ndisconnected loops give significant contributions to the form factors.",
        "positive": "<x>_{u-d} from lattice QCD at nearly physical quark masses: We determine the second Mellin moment of the isovector quark parton\ndistribution function <x>_{u-d} from lattice QCD with N_f=2 sea quark flavours,\nemploying the non-perturbatively improved Wilson-Sheikholeslami-Wohlert action\nat a pseudoscalar mass of 157(6) MeV. The result is converted\nnon-perturbatively to the RI'-MOM scheme and then perturbatively to the MSbar\nscheme at a scale mu = 2 GeV. As the quark mass is reduced we find the lattice\nprediction to approach the value extracted from experiments."
    },
    {
        "anchor": "Critical slowing down and error analysis in lattice QCD simulations: We study the critical slowing down towards the continuum limit of lattice QCD\nsimulations with Hybrid Monte Carlo type algorithms. In particular for the\nsquared topological charge we find it to be very severe with an effective\ndynamical critical exponent of about 5 in pure gauge theory. We also consider\nWilson loops which we can demonstrate to decouple from the modes which slow\ndown the topological charge. Quenched observables are studied and a comparison\nto simulations of full QCD is made. In order to deal with the slow modes in the\nsimulation, we propose a method to incorporate the information from slow\nobservables into the error analysis of physical observables and arrive at safer\nerror estimates.",
        "positive": "Equation of state for two-flavor QCD with an improved Wilson quark\n  action at non-zero chemical potential: The QCD thermodynamics on the lattice provides fundamental theoretical\ngrounds to analyze the various experimental data in relativistic heavy ion\ncollisions. So far, most of the numerical simulations on the lattice have been\nperformed by using the staggered-type fermion actions. Therefore it is\nimportant to carry out studies using different fermion formulations to test the\nuncertainties of the lattice QCD results. For this purpose, we perform\nsystematic simulations of two-flavor QCD with an improved Wilson quark action\nto investigate the equation of state. We report the current status of our\nproject and show the preliminary results of the Taylor expansion coefficients\nof the thermodynamic grand partition function in terms of chemical potential."
    },
    {
        "anchor": "Jet quenching from the lattice: We present a lattice study of the momentum broadening experienced by a hard\nparton in the quark-gluon plasma. In particular, the contributions to this\nreal-time phenomenon from soft modes are extracted from a set of\ngauge-invariant operators in a dimensionally reduced effective theory\n(electrostatic QCD), which can be simulated on a Euclidean lattice. At the\ntemperatures accessible to present experiments, the soft contributions to the\njet quenching parameter are found to be quite large. We compare our results to\nphenomenological models and to holographic computations.",
        "positive": "Dynamical Eightfold Way in Strongly Coupled Lattice QCD: We obtain from the quark-gluon dynamics, the Gell'Mann-Ne'eman eightfold way\nbaryons in an imaginary-time functional integral formulation of 3+1 lattice QCD\nin the strong coupling regime (small hopping parameter $\\kappa>0$). The model\nhas ${\\rm SU}(3)_c$ gauge and global ${\\rm SU}(3)_f$ flavor symmetries. In the\nsubspace of the physical Hilbert space of vectors with an odd number of quarks,\nthe baryons are associated with isolated dispersion curves in the\nenergy-momentum spectrum. The spin 1/2 octet and spin 3/2 decuplet baryons have\nasymptotic mass $-3\\ln\\kappa$ and for each baryon there is an antibaryon with\nidentical spectral properties. All the masses have the form\n$M=-3\\ln\\kappa-3\\kappa^3/4+\\kappa^6 r(\\kappa)$, with $r(\\kappa)$ real analytic.\nFor each member of the octet $r(\\kappa)$ is the same; for each member of the\ndecuplet, $r(0)$ is the same. So, there is no mass splitting within the octet,\nand within the decuplet up to and including ${\\cal O}(\\kappa^6)$. However,\nthere is an octet-decuplet mass difference of $3\\kappa^6/4+{\\cal O}(\\kappa^7)$.\nThe baryon and antibaryon spectrum is the only one up to near the meson-baryon\nthreshold of nearly $-5\\ln\\kappa$. A decoupling of hyperplane method is used to\nnaturally unveil the form of the baryon composite fields (no a priori\nguesswork), to show the existence of particles and their multiplicities using a\nspectral representation for the two-baryon correlation. We also obtain the\n(anti-)baryon dispersion curves which admit the representation $w(\\kappa,\\vec\np)= -3\\ln\\kappa -3\\kappa^3/4+\\kappa^3\\sum_{j=1,2,3} (1-\\cos ^j)/4+r(\\kappa,\\vec\np)$, where $r(\\kappa,\\vec p)$ is of ${\\cal O}(\\kappa^6)$."
    },
    {
        "anchor": "SU(N) gauge theories in 2+1 dimensions: We calculate the mass spectra and string tensions of SU(2), SU(3), SU(4) and\nSU(5) gauge theories in 2+1 dimensions. We do so by simulating the\ncorresponding lattice theories and then extrapolating dimensionless mass ratios\nto the continuum limit. We find that such mass ratios are, to a first\napproximation, independent of the number of colours and that the remaining\ndependence can be accurately reproduced by a simple O(1/N.N) correction. This\nprovides us with a prediction of these mass ratios for all SU(N) theories in\n2+1 dimensions and demonstrates that these theories are already `close' to\nN=infinity for N=2. We find that the theory retains a non-zero confining string\ntension as N goes to infinity and that the dimensionful coupling g.g is\nproportional to 1/N at large N, when expressed in units of the dynamical length\nscale of the theory. During the course of these calculations we study in detail\nthe effects of including over-relaxation in the Monte Carlo, of using a\nmean-field improved coupling to extrapolate to the continuum limit, and the use\nof space-time asymmetric lattice actions to resolve heavy glueball correlators.",
        "positive": "A derivative-based approach for the leading order hadronic contribution\n  to $g_\u03bc-2$: We describe a lattice approach to calculating the leading-order hadronic\ncontribution to the anomalous magnetic moment of the muon. We employ lattice\nmomentum derivatives, in both the spatial and temporal directions, to determine\nthe hadronic vacuum polarization scalar at low momenta and construct a smooth,\nintregrable function in this momentum region. The method is tested on one\nhex-smeared Wilson-quark lattice ensemble with physical pion masses."
    },
    {
        "anchor": "Thermodynamics of Two Flavor QCD to Sixth Order in Quark Chemical\n  Potential: We present results of a simulation of 2-flavor QCD on a 4x16^3 lattice using\np4-improved staggered fermions with bare quark mass m/T=0.4. Derivatives of the\nthermodynamic grand canonical partition function Z(V,T,mu_u,mu_d) with respect\nto chemical potentials mu_(u,d) for different quark flavors are calculated up\nto sixth order, enabling estimates of the pressure and the quark number density\nas well as the chiral condensate and various susceptibilities as functions of\nmu_q = (mu_u + mu_d)/2 via Taylor series expansion. Furthermore, we analyze\nbaryon as well as isospin fluctuations and discuss the relation between the\nradius of convergence of the Taylor series and the chiral critical point in the\nQCD phase diagram. We argue that bulk thermodynamic observables do not, at\npresent, provide direct evidence for the existence of a chiral critical point\nin the QCD phase diagram. Results are compared to high temperature perturbation\ntheory as well as a hadron resonance gas model.",
        "positive": "New higher-order transition in causal dynamical triangulations: We reinvestigate the recently discovered bifurcation phase transition in\nCausal Dynamical Triangulations (CDT) and provide further evidence that it is a\nhigher order transition. We also investigate the impact of introducing matter\nin the form of massless scalar fields to CDT. We discuss the impact of scalar\nfields on the measured spatial volumes and fluctuation profiles in addition to\nanalysing how the scalar fields influence the position of the bifurcation\ntransition."
    },
    {
        "anchor": "Scattering of unstable particles in a finite volume: the case of pi rho\n  scattering and the a1(1260) resonance: We present a way to evaluate the scattering of unstable particles quantized\nin a finite volume with the aim of extracting physical observables for infinite\nvolume from lattice data. We illustrate the method with the $\\pi\\rho$\nscattering which generates dynamically the axial-vector $a_1(1260)$ resonance.\nEnergy levels in a finite box are evaluated both considering the $\\rho$ as a\nstable and unstable resonance and we find significant differences between both\ncases. We discuss how to solve the problem to get the physical scattering\namplitudes in the infinite volume, and hence phase shifts, from possible\nlattice results on energy levels quantized inside a finite box.",
        "positive": "Non-perturbatively gauge-fixed compact $U(1)$ lattice gauge theory: An extensive study of the compact $U(1)$ lattice gauge theory with a higher\nderivative gauge-fixing term and a suitable counter-term has been undertaken to\ndetermine the nature of the possible continuum limits for a wide range of the\nparameters, especially at strong gauge couplings ($g>1$), adding to our\nprevious study at a single gauge coupling $g=1.3$ \\cite{DeSarkar2016}. Our\nmajor conclusion is that a continuum limit of free massless photons (with the\nredundant pure gauge degrees of freedom decoupled) is achieved at any gauge\ncoupling, not necessarily small, provided the coefficient $\\tilde{\\kappa}$ of\nthe gauge-fixing term is sufficiently large. In fact, the region of continuous\nphase transition leading to the above physics in the strong gauge coupling\nregion is found to be analytically connected to the point $g=0$ and\n$\\tilde{\\kappa} \\rightarrow \\infty$ where the classical action has a global\nunique minimum, around which weak coupling perturbation theory in bare\nparameters is defined, controlling the physics of the whole region. A second\nmajor conclusion is that, local algorithms like Multihit Metropolis fail to\nproduce faithful field configurations with large values of the coefficient\n$\\tilde{\\kappa}$ of the higher derivative gauge-fixing term and at large\nlattice volumes. A global algorithm like Hybrid Monte Carlo, although at times\nslow to move out of metastabilities, generally is able to produce faithful\nconfigurations and has been used extensively in the current study."
    },
    {
        "anchor": "Screening without screening: baryon energy at high baryon density: We compute the Coulomb interaction energy of dense sets of static quarks in a\ncompact volume (much smaller than the lattice volume) containing one quark per\nlattice site. The quark color charges are combined into either a set of\nthree-quark nucleon states, or into a non-factorizable \"one big hadron\" state.\nIn both cases we find that the energy per quark is roughly constant as the\nvolume of quarks increases. A surprise is that if we construct the nucleon\nstates from sets of three quarks chosen at random in the volume, then the\nenergy per quark remains roughly constant, even as the average distance between\nquarks in a nucleon state grows as the volume increases. This energy dependence\nof a nucleon in a dense medium is at odds with the behavior of an isolated\nnucleon as quark separation increases, and for static quarks it is not easily\nexplicable in terms of some version of Debye screening.",
        "positive": "Lowest eigenvalues of the Dirac operator for two color QCD at nonzero\n  chemical potential: We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)\nand U(1) gauge theory as well as in full QCD with two colors and finite\nchemical potential. Along the strong-coupling axis up to the phase transition,\nthe low-lying Dirac spectrum of these quantum field theories is well described\nby random matrix theory and exhibits universal behavior. Related results for\ngauge theories with minimal coupling are discussed in the chirally symmetric\nphase and no universality is seen for the microscopic spectral densities."
    },
    {
        "anchor": "A new moving frame to extract scattering phases in lattice QCD: We present a derivation of the finite-size formulae in a moving frame with\ntotal momentum P=(2\\pi/L)(e1+e2). These formulae allow us to calculate the\nS-wave and P-wave scattering phases at more energies with a fixed lattice size\nand thus help us to determine the resonance parameters precisely.",
        "positive": "Progress in the Nucleon Electric Dipole Moment Calculations in Lattice\n  QCD: Electric dipole moments (EDMs), which are sought as evidence of CP violation,\nrequire lattice calculations to connect constraints from experiments to limits\non the strong CP violation within QCD or CP violation in new physics beyond the\nstandard model. Nucleon EDM calculations on a lattice are notoriously hard due\nto large statistical noise, chiral symmetry violating effects, and potential\nmixing of the EDM and the anomalous magnetic moment of the nucleon. In this\nreport, details of ongoing lattice calculations of proton and neutron EDMs\ninduced by the QCD $\\theta$-term and the quark chromo-EDM, the lowest-dimension\neffective CP-violating quark-gluon interaction are presented. Our calculation\nemploys chiral-symmetric fermion discretization. An assessment of feasibility\nof nucleon EDM calculations at the physical point is discussed."
    },
    {
        "anchor": "Free fermionic propagators on a lattice: A method used recently to obtain a formalism for classical fields with\nnon-local actions preserving chiral symmetry and uniqueness of fermion fields\nyields a discrete version of Huygens' principle with free discrete propagators\nthat recover their continuum forms in certain limit.",
        "positive": "Non-perturbative thermal QCD at all temperatures: the case of mesonic\n  screening masses: We present a strategy based on the step-scaling technique to study\nnon-perturbatively thermal QCD up to very high temperatures. As a first\nconcrete application, we compute the flavour non-singlet meson screening masses\nat 12 temperatures covering the range from $T \\sim 1$ GeV up to $\\sim 160$ GeV\nin the theory with three massless quarks. The calculation is carried out by\nMonte Carlo simulations on the lattice by considering large spatial extensions\nin order to have negligible finite volume effects. For each temperature we have\nsimulated 3 or 4 values of the lattice spacing, so as to perform the continuum\nlimit extrapolation with confidence at a few permille accuracy. Chiral symmetry\nrestoration manifests itself in our results through the degeneracy of the\nvector and the axial vector channels and of the scalar and the pseudoscalar\nones. In the entire range of temperatures explored, the meson screening masses\ndeviate from the free theory result, $2 \\pi T$, by at most a few percent. These\ndeviations, however, cannot be explained by the known leading term in the QCD\ncoupling constant $g$ up to the highest temperature, where other contributions\nare still very relevant. In particular the vector-pseudoscalar mass splitting\nturns out to be of $O(g^4)$ in the entire range explored, and it remains\nclearly visible up to the highest temperature, where the two screening masses\nare still significantly different within our numerical precision. The pattern\nof different contributions that we have found explains why it has been\ndifficult in the past to match non-perturbative lattice results at $T \\sim 1$\nGeV with the analytic behaviour at asymptotically high temperatures."
    },
    {
        "anchor": "The continuum limit of the quark mass step scaling function in quenched\n  lattice QCD: The renormalisation group running of the quark mass is determined\nnon-perturbatively for a large range of scales, by computing the step scaling\nfunction in the Schroedinger Functional formalism of quenched lattice QCD both\nwith and without O(a) improvement. A one-loop perturbative calculation of the\ndiscretisation effects has been carried out for both the Wilson and the\nClover-improved actions and for a large number of lattice resolutions. The\nnon-perturbative computation yields continuum results which are regularisation\nindependent, thus providing convincing evidence for the uniqueness of the\ncontinuum limit. As a byproduct, the ratio of the renormalisation group\ninvariant quark mass to the quark mass, renormalised at a hadronic scale, is\nobtained with very high accuracy.",
        "positive": "Field Theoretic Calculation of the Universal Amplitude Ratio of\n  Correlation Lengths in 3D-Ising Systems: In three-dimensional systems of the Ising universality class the ratio of\ncorrelation length amplitudes for the high- and low-temperature phases is a\nuniversal quantity. Its field theoretic determination apart from the\n$\\epsilon$-expansion represents a gap in the existing literature. In this\narticle we present a method, which allows to calculate this ratio by\nrenormalized perturbation theory in the phases with unbroken and broken\nsymmetry of a one-component $\\phi^4$-theory in fixed dimensions $D=3$. The\nresults can be expressed as power series in the renormalized coupling constant\nof either of the two phases, and with the knowledge of their fixed point values\nnumerical estimates are obtainable. These are given for the case of a two-loop\ncalculation."
    },
    {
        "anchor": "Gauge invariant extremization on the lattice: Recently, a method was proposed and tested to find saddle points of the\naction in simulations of non-abelian lattice gauge theory. The idea, called\n`extremization', is to minimize $\\int(\\dl S/\\dl A_\\mu)^2$. The method was\nimplemented in an explicitly gauge variant way, however, and gauge dependence\nshowed up in the results.\n  Here we show how extremization can be formulated in a way that preserves\ngauge invariance on the lattice. The method applies to any gauge group and any\nlattice action. The procedure is worked out in detail for the standard\nplaquette action with gauge groups U(1) and SU(N).",
        "positive": "Extended hadron and two-hadron operators of definite momentum for\n  spectrum calculations in lattice QCD: Multi-hadron operators are crucial for reliably extracting the masses of\nexcited states lying above multi-hadron thresholds in lattice QCD Monte Carlo\ncalculations. The construction of multi-hadron operators with significant\ncoupling to the lowest-lying multi-hadron states of interest involves combining\nsingle hadron operators of various momenta. The design and implementation of\nlarge sets of spatially-extended single-hadron operators of definite momentum\nand their combinations into two-hadron operators are described. The single\nhadron operators are all assemblages of gauge-covariantly-displaced, smeared\nquark fields. Group-theoretical projections onto the irreducible\nrepresentations of the symmetry group of a cubic spatial lattice are used in\nall isospin channels. Tests of these operators on 24^3 x 128 and 32^3 x 256\nanisotropic lattices using a stochastic method of treating the low-lying modes\nof quark propagation which exploits Laplacian Heaviside quark-field smearing\nare presented. The method provides reliable estimates of all needed\ncorrelations, even those that are particularly difficult to compute, such as\neta eta -> eta eta in the scalar channel, which involves the subtraction of a\nlarge vacuum expectation value. A new glueball operator is introduced, and the\nevaluation of the mixing of this glueball operator with a quark-antiquark\noperator, pi-pi, and eta-eta operators is shown to be feasible."
    },
    {
        "anchor": "Chiral Corrections to Lattice Calculations of Charge Radii: Logarithmic divergences in pion and proton charge radii associated with\nchiral loops are investigated to assess systematic uncertainties in current\nlattice determinations of charge radii. The chiral corrections offer a possible\nsolution to the long standing problem of why present lattice calculations yield\nproton and pion radii which are similar in size.",
        "positive": "Dimensionally reduced U(1)+Higgs theory in the broken phase: We apply dimensional reduction to the finite temperature U(1)+Higgs theory\nand study the properties of the reduced 3-dimensional theory in the broken\nphase using lattice Monte Carlo simulations. We compute analytically the scalar\ncondensate in optimized 2-loop perturbation theory and the correlators in\n1-loop perturbation theory. These quantities are also calculated numerically.\nThe two results for the condensate agree well but a 25\\% difference is observed\nfor the scalar correlator, indicating the need for optimized 2-loop\nperturbative results."
    },
    {
        "anchor": "Non-equilibrium Higgs transition in classical scalar electrodynamics: Real time rearrangement of particle spectra is studied numerically in a U(1)\nGauge+Higgs system, in the unitary gauge and in three spatial dimensions. The\ncold system starts from the symmetric phase. Evolution of the partial energy\ndensities and pressures reveal well-defined equations of state for the\nlongitudinal and transversal gauge fields very early. Longitudinal modes are\nexcited more efficiently and thermalize the slowest. Hausdorff-dimension of the\nHiggs-defect manifold, eventually seeding vortex excitations is thoroughly\ndiscussed. Scaling dependence of the vortex density on the characteristic time\nof the symmetry breaking transition is established.",
        "positive": "Anomalous Chiral Behavior in Quenched Lattice QCD: A study of the chiral behavior of pseudoscalar masses and decay constants is\ncarried out in quenched lattice QCD with Wilson fermions. Using the modified\nquenched approximation (MQA) to cure the exceptional configuration problem,\naccurate results are obtained for pion masses as low as $\\approx$ 200 MeV. The\nanomalous chiral log effect associated with quenched $\\eta'$ loops is studied\nin both the relation between $m_{\\pi}^2$ vs. $m_q$ and in the light-mass\nbehavior of the pseudoscalar and axial vector matrix elements. The size of\nthese effects agrees quantitatively with a direct measurement of the $\\eta'$\nhairpin graph, as well as with a measurement of the topological susceptibility,\nthus providing several independent and quantitatively consistent determinations\nof the quenched chiral log parameter $\\delta$. For $\\beta=5.7$ with\nclover-improved fermions $(C_{sw} =1.57)$ all results are consistent with\n$\\delta=0.065\\pm 0.013$ ."
    },
    {
        "anchor": "What we can learn from two-dimensional QCD-like theories at finite\n  density: We study generic properties of strongly interacting matter at finite density\nas relevant to heavy-ion collisions at moderate beam energies or the physics of\nneutron stars and their mergers. Because of the fermion-sign problem in lattice\nQCD, here we simulate QCD-like theories without this problem at finite density.\nThese theories (two-color QCD, G2-QCD, or adjoint QCD) typically contain\nbosonic baryons, for example diquarks, or other more exotic states of matter.\nIt is therefore important to understand the effects of such bosonic matter and\ndisentangle them from fermionic baryons where they exist to draw conclusions\nfor QCD. Simulations of these theories, for instance G2-QCD, reveal an\ninteresting and rich phase diagram at zero temperature. Many open questions\narise, partly due to the lack of high precision or large volume/continuum data.\nThis is the reason why we study two-dimensional QCD-like theories. In this\ncontribution we shall discuss differences between QCD-like theories at baryon\nchemical and isospin chemical potential. Furthermore we present simulation\nresults on the phase diagram and spectroscopy at finite density for G2- and\ntwo-color-QCD and compare it to free lattice fermions.",
        "positive": "High accuracy simulations of d=4 SU(3) qcd-string: We present here the results of our high accuracy simulations of $q\\bar q$\npotential in $d=4$ SU(3) Yang-Mills theory. We measure this quantity by\nmeasuring the {\\it Polyakov Loop Correlators} using the {\\it exponential\nvariance reduction technique(multilevel)} of Luscher and Weisz. We further use\nnumerical integration of the one-link integrals of SU(3) theory by adopting\ntechniques proposed by de Forcrand and Roiesnell achieving significant speed-up\nin the process. Measurements were done at $\\beta = 5.7$ on $24^3x32$ as well as\n$32^4$ lattices for separations between the Polyakov loops in the range $r =\n2-9$ in lattice units. We analyse the results in terms of the force between\n$q\\bar q$ pair as well as in terms of a {\\em scaled second derivative} of the\npotential. We show that the data is accurate enough to distinguish between\ndifferent string models and that it seems to favour the expression for ground\nstate energy of a Nambu-Goto string. We conclude by discussing future plans."
    },
    {
        "anchor": "The decay constant of the first excited pion from lattice QCD: We review the theory that predicts that the decay constant of the excited\nlight pseudo-scalar mesons are suppressed in the chiral limit relative to the\npion decay constant. We compute the decay constant of the first excited pion\n($\\pi^\\prime$) using unquenched QCD at a fixed lattice spacing with sea quarks\nof mass as low as a third the mass of the strange quark. The final result is\nvery sensitive to the improvement conditions. We obtain $f_{\\pi^\\prime} /\nf_{\\pi}$ = 0.078(93) in the chiral limit.",
        "positive": "Vortices, Symmetry Breaking, and Temporary Confinement in SU(2)\n  Gauge-Higgs Theory: We further investigate center vortex percolation and Coulomb gauge remnant\nsymmetry breaking in the SU(2) gauge-Higgs model. We show that string breaking\nis visible in Polyakov line correlators on the center projected lattice, that\nour usual numerical tests successfully relate P-vortices to center vortices,\nand that vortex removal removes the linear potential, as in the pure gauge\ntheory. This data suggests that global center symmetry is not essential to the\nvortex confinement mechanism. But we also find that the line of vortex\npercolation-depercolation transitions, and the line of remnant symmetry\nbreaking transitions, do not coincide in the SU(2)-Higgs phase diagram. This\nnon-uniqueness of transition lines associated with non-local order parameters\nfavors a straightforward interpretation of the Fradkin-Shenker theorem, namely:\nthere is no unambiguous distinction, in the SU(2) gauge-Higgs models, between a\n\"confining\" phase and a Higgs phase."
    },
    {
        "anchor": "Chiral Lagrangians from lattice gauge theories in the strong coupling\n  limit: We derive nonlinear sigma models (chiral Lagrangians) over symmetric spaces\nU(n), U(2n)/Sp(2n), and U(2n)/O(2n) from U(N), O(N), and Sp(2N) lattice gauge\ntheories coupled to n flavors of staggered fermions, in the large-N and g^2 N\nlimit. To this end, we employ Zirnbauer's color-flavor transformation. We prove\nthe spatial homogeneity of the vacuum configurations of mesons by explicitly\nsolving the large-N saddle point equations, and thus establish the above\npatterns of spontaneous chiral symmetry breaking without any assumptions.",
        "positive": "$\\mathbf{c_\\textbf{SW}}$ at One-Loop Order for Brillouin Fermions: Wilson-like Dirac operators can be written in the form\n$D=\\gamma_\\mu\\nabla_\\mu-\\frac {ar}{2} \\Delta$. For Wilson fermions the standard\ntwo-point derivative $\\nabla_\\mu^{(\\mathrm{std})}$ and 9-point Laplacian\n$\\Delta^{(\\mathrm{std})}$ are used. For Brillouin fermions these are replaced\nby improved discretizations $\\nabla_\\mu^{(\\mathrm{iso})}$ and\n$\\Delta^{(\\mathrm{bri})}$ which have 54- and 81-point stencils respectively. We\nderive the Feynman rules in lattice perturbation theory for the Brillouin\naction and apply them to the calculation of the improvement coefficient\n${c_\\mathrm{SW}}$, which, similar to the Wilson case, has a perturbative\nexpansion of the form\n${c_\\mathrm{SW}}=1+{c_\\mathrm{SW}}^{(1)}g_0^2+\\mathcal{O}(g_0^4)$. For $N_c=3$\nwe find ${c_\\mathrm{SW}}^{(1)}_\\mathrm{Brillouin} =0.12362580(1) $, compared to\n${c_\\mathrm{SW}}^{(1)}_\\mathrm{Wilson} = 0.26858825(1)$, both for $r=1$."
    },
    {
        "anchor": "On the topological content of SU(2) gauge fields below T_c: Finite temperature Euclidean SU(2) lattice gauge fields generated in the\nconfinement phase close to the deconfinement phase transition are subjected to\ncooling. The aim is to identify long-living, almost-classical local excitations\nwhich carry (generically non-integer) topological charge. Two kinds of spatial\nboundary conditions (fixed holonomy and standard periodic boundary conditions)\nare applied. For the lowest-action almost-classical configurations we find that\ntheir relative probability semi-quantitatively agrees for both types of\nboundary conditions. We find calorons with unit topological charge as well as\n(anti-)selfdual lumps (BPS-monopoles or dyons) combined in pairs of non-integer\n(equal or opposite sign) topological charge. For calorons and separated pairs\nof equal-sign dyons obtained by cooling we have found that (i) the gluon field\nis well-described by Kraan-van Baal solutions of the Euclidean Yang-Mills field\nequations and (ii) the lowest Wilson-fermion modes are well-described by\nanalytic solutions of the corresponding Dirac equation. For metastable\nconfigurations found at higher action, the multi-center structure can be\ninterpreted in terms of dyons and antidyons, using the gluonic and fermionic\nindicators as in the dyon-pair case. Additionally, the Abelian monopole\nstructure and field strength correlators between the centers are useful to\nanalyse the configurations in terms of dyonic constituents. We argue that a\nsemi-classical approximation of the non-zero temperature path integral should\nbe built on superpositions of solutions with non-trivial holonomy.",
        "positive": "What we do understand of Colour Confinement: A review is presented of what we understand of colour confinement in QCD.\nLattice formulation provides evidence that QCD vacuum is a dual superconductor:\nthe chromoelectric field of a $q\\bar q$ pair is constrained by dual Meissner\neffect into a dual Abrikosov flux tube and the static potential energy is\nproportional to the distance."
    },
    {
        "anchor": "The gluon condensate from gauge invariant vortex vacuum texture: In SU(2) lattice gauge theory, a new self-restricted cooling procedure is\ndeveloped to uncover the gauge invariant vortex vacuum texture. The emerging\nvortex vacuum structure amounts to the full string tension and gives rise to a\nmass dimension four condensate which is of pure vortex origin.",
        "positive": "Landau gauge gluon and ghost propagators from two-flavor lattice QCD at\n  T > 0: In this contribution we extend our unquenched computation of the Landau gauge\ngluon and ghost propagators in lattice QCD at non-zero temperature. The study\nwas aimed at providing input for investigations employing continuum functional\nmethods. We show data which correspond to pion mass values between 300 and 500\nMeV and are obtained for a lattice size 32**3 x 12. The longitudinal and\ntransversal components of the gluon propagator turn out to change smoothly\nthrough the crossover region, while the ghost propagator exhibits only a very\nweak temperature dependence. For a pion mass of around 400 MeV and the\nintermediate temperature value of approx. 240 MeV we compare our results with\nadditional data obtained on a lattice with smaller Euclidean time extent N_t =\n8, 10 and find a reasonable scaling behavior."
    },
    {
        "anchor": "Masses, Decay Constants and Electromagnetic Form-factors with Twisted\n  Boundary Conditions: Using Chiral Perturbation Theory at one-loop we analyze the consequences of\ntwisted boundary conditions. We point out that due to the broken Lorentz and\nreflection symmetry a number of unexpected terms show up in the expressions. We\nexplicitly discuss the pseudo-scalar octet masses, axial-vector and\npseudo-scalar decay constants and electromagnetic form-factors. We show how the\nWard identities are satisfied using the momentum dependent masses and the\nnon-zero vacuum-expectation-values values for the electromagnetic (vector)\ncurrents. Explicit expressions at one-loop are provided and an appendix\ndiscusses the needed one-loop twisted finite volume integrals.",
        "positive": "Abelian projection and studies of gauge-variant quantities in lattice\n  QCD without gauge fixing: We suggest a new (dynamical) Abelian projection of the lattice QCD. It\ncontains no gauge condition imposed on gauge fields so that Gribov copying is\navoided. Configurations of gauge fields that turn into monopoles in the Abelian\nprojection can be classified in a gauge invariant way. In the continuum limit,\nthe theory respects the Lorentz invariance. A similar dynamical reduction of\nthe gauge symmetry is proposed for studies of gauge-variant correlators (like a\ngluon propagator) in lattice QCD. Though the procedure is harder for numerical\nsimulations, it is free of gauge fixing artifacts, like the Gribov horizon and\ncopies."
    },
    {
        "anchor": "High Precision Simulation Techniques for Lattice Field Theory: An overview is given over the recently developed and now widely used Monte\nCarlo algorithms with reduced or eliminated critical slowing down. The basic\ntechniques are overrelaxation, cluster algorithms and multigrid methods. With\nthese tools one is able to probe much closer than before the universal\ncontinuum behavior of field theories on the lattice.",
        "positive": "Screening of sources in higher representations of SU(N) gauge theories\n  at zero and finite temperature: Completion of the Svetitsky-Yaffe conjecture in some (2+1) dimensional SU(N)\ngauge theories allows mapping Polyakov loops in higher representations of the\ngauge group into suitable conformal operators of the corresponding 2D CFT. As a\nconsequence, the critical exponents of the correlators of these Polyakov loops\nare determined. The functional form of these correlators suggests a general\nAnsatz to describe the large-distance screening of higher-representation\nsources at zero temperature in any space-time dimension. A generalised Wilson\nloop in which along part of its trajectory a source is converted in a gauge\ninvariant way into higher representations with same N-ality could be used to\nestimate the decay scale of the unstable strings"
    },
    {
        "anchor": "Recent Developments in Monte Carlo Simulations of First-Order Phase\n  Transitions: In the past few years considerable progress has been made in Monte Carlo\nsimulations of first-order phase transitions and in the analysis of the\nresulting finite-size data. In this paper special emphasis will be placed on\nmulticanonical simulations using multigrid update techniques, on numerical\nestimates of interface tensions, and on accurate methods for determining the\ntransition point and latent heat.",
        "positive": "Exploring Higgs Sector Spectroscopy: The Higgs sector of the standard model is field-theoretically a very\ninteresting theory. Because strong and weak coupling domains are continuously\nconnected, only quantitative changes distinguish the various regions.\nEspecially, this is true for the asymptotic spectrum, which can only consist\nout of gauge-invariant composite, i. e. bound, states. Since in some regions of\nparameter space even Regge trajectories are expected to exist, there is\nimmediately the possibility that resonances may also be present in the\nparameter region characteristic of the standard model Higgs sector. This\npossibility is discussed in some detail, starting from the definition of the\ntheory to spectroscopy, including excited state analysis, to some\nconsiderations whether this could have experimental consequences. The strongest\nlimitation for this exploration turns out to be that the gauge coupling without\nfermions runs much faster, and the gauge sector is therefore potentially\naffected."
    },
    {
        "anchor": "Relativistic-invariant formulation of the NREFT three-particle\n  quantization condition: A three-particle quantization condition on the lattice is written down in a\nmanifestly relativistic-invariant form by using a generalization of the\nnon-relativistic effective field theory (NREFT) approach. Inclusion of the\nhigher partial waves is explicitly addressed. A partial diagonalization of the\nquantization condition into the various irreducible representations of the\n(little groups of the) octahedral group has been carried out both in the\ncenter-of-mass frame and in moving frames. Furthermore, producing synthetic\ndata in a toy model, the relativistic invariance is explicitly demonstrated for\nthe three-body bound state spectrum.",
        "positive": "The Schwinger function, confinement and positivity violation in pure\n  gauge QED: The lattice regularized pure gauge compact U(1) theory is an ideal laboratory\nto explore how confinement is realized as its phase diagram has a confined and\na deconfined phase that depends on the value of the coupling constant, i.e. on\n$\\beta$. Herein, the connection between confinement and positivity violation\nthrough the Schwinger function associated with the Landau gauge photon\npropagator is investigated. The simulations reported show a very clear link\nbetween the realization of confinement and positivity violation of the photon\nSchwinger function and, therefore, of the photon K\\\"all\\'en-Lehmann spectral\ndensity. Furthermore, a mass scale that characterizes the decay of the\nSchwinger function for small time separations is computed and used to\ndistinguish the two phases of the theory."
    },
    {
        "anchor": "Pion in a Box: The residual mass of the pion in a finite spatial box at vanishing quark\nmasses, the mass gap, is computed with two flavors of dynamical clover\nfermions. The result is compared with predictions of chiral perturbation theory\nin the delta regime.",
        "positive": "A survey of large N continuum phase transitions: The main focus of this talk is the physics of large N QCD on a continuum\ntorus. A cascade of phase transitions associated with the breaking of U(1)\nsymmetries will be discussed. The continuum Wilson loop as a function of its\narea will be discussed along with its universality properties and the\nassociated double scaling limit. Some recent progress in twisted Eguchi-Kawai\nis presented. Gauge field topology and $\\theta$ vacuua are also discussed in\nthe context of large N gauge theories. Phase transitions in 2D large N\nprincipal chiral models are compared with similar transitions in large $N$\ngauge theories. Finally, connections to some topics in string theory and\ngravity are briefly described."
    },
    {
        "anchor": "Quark localization in QCD above $T_c$: It was previously found that at high temperature the lowest part of the QCD\nDirac spectrum consists of localized modes obeying Poisson statistics. Higher\nup in the spectrum, modes become delocalized and their statistics can be\ndescribed by random matrix theory. The transition from localized to delocalized\nmodes is analogous to the Anderson metal-insulator transition. Here we use\ndynamical QCD simulations with staggered quarks to study this localization\nphenomenon. We show that the \"mobility edge\", separating localized and\ndelocalized modes, scales properly in the continuum limit and rises steeply\nwith the temperature. Using very high statistics simulations in large volumes\nwe find that the density of localized modes scales precisely with the spatial\nvolume and even at $T=2.6T_{c}$ the lowest part of the spectrum extends all the\nway down to zero with no evidence of a spectral gap.",
        "positive": "Bound state of two-nucleon systems in quenched lattice QCD: We address the issue of bound state in the two-nucleon system in lattice QCD\nwith the quenched approximation at the lattice spacing of a =0.128 fm using a\nheavy quark mass corresponding to m_pi = 0.8 GeV. To distinguish a bound state\nfrom an attractive scattering state, we investigate the volume dependence of\nthe energy difference between the ground state and the free two-nucleon state\nby changing the spatial extent of the lattice from 3.1 fm to 12.3 fm. A finite\nenergy difference left in the infinite spatial volume limit leads us to the\nconclusion that the measured ground states for not only spin triplet but also\nsinglet channels are bounded. Furthermore the existence of the bound state is\nconfirmed by investigating the properties of the energy for the first excited\nstate obtained by 2x2 diagonalization method. The scattering lengths for both\nchannels are evaluated by the finite volume formula derived by Luscher."
    },
    {
        "anchor": "Universality of the Nf=2 Running Coupling: We investigate universality of the Nf=2 running coupling in the Sch\\\"odinger\nfunctional scheme, by calculating the step scaling function in lattice QCD with\nthe renorm alization group (RG) improved gauge action at both weak(u=0.9796)\nand strong(u=3.3340) couplings, where u=\\bar{g}^2_SF with \\bar{g}_SF being the\nrunning coupling in this scheme. In our main calculations, we use the\ntree-level value for O(a) improvement coefficients of boundary gauge fields. In\naddition we employ the 1-loop value for them in order to see how scaling\nbehaviours are affected by them. In the continuum limit, the step scaling\nfunction obtained from the RG improved gauge actions agrees with the previous\nresult obtained from the plaquette action within errors at both couplings,\nthough errors of our result are larger. Combined fits using all data with the\nRG improved action as well as the plaquette action reduce errors in the\ncontinuum limit by 2% at the weak coupling and 22% at the strong coupling.",
        "positive": "SU(N) Gauge Theories with C-Periodic Boundary Conditions: II. Small\n  Volume Dynamics: The dynamics of SU(N) gauge theories, especially for N=3, in a small\nC-periodic box are investigated. We identify the fields that mimimize the\nenergy---the torons---and determine which of these ``classical'' vacua are\nstable quantum mechanically. The stable torons break cubic symmetry, which has\ninteresting consequences on the spectrum. At any of the stable torons there are\nalso quartic modes. Since all C-periodic boundary conditions are\ngauge-equivalent, we choose a convenient version, for which the quartic modes\nare constant modes, and compute the effective Hamiltonian to one loop in\nperturbation theory."
    },
    {
        "anchor": "Light hadron spectroscopy with O(a) improved dynamical fermions: We present the first results for the static quark potential and the light\nhadron spectrum using dynamical fermions at $\\beta=5.2$ using an O(a) improved\nWilson fermion action together with the standard Wilson plaquette action for\nthe gauge part. Sea quark masses were chosen such that the pseudoscalar-vector\nmass ratio, m_PS/m_V$, varies from 0.86 to 0.67. Finite-size effects are\nstudied by using three different volumes, 8^3\\cdot 24, 12^3\\cdot 24 and\n16^3\\cdot 24. Comparing our results to previous ones obtained using the\nquenched approximation, we find evidence for sea quark effects in quantities\nlike the static quark potential and the vector-pseudoscalar hyperfine\nsplitting.",
        "positive": "Thermodynamics for SU(2) pure gauge theory using gradient flow: We present the scale-setting function and the equation of state of the pure\nSU(2) gauge theory using the gradient flow method. We propose a reference scale\nt0 for the SU(2) gauge theory satisfying $t^2\\langle E \\rangle|_{t=t_0} = 0.1$.\nThis reference value is fixed by a natural scaling-down of the standard\nt0-scale for the SU(3) gauge theory based on the perturbative analyses. We also\nshow the thermodynamic quantities as a function of $T/T_c$, which are derived\nby the energy-momentum tensor using the small flow time expansion of the\ngradient flow."
    },
    {
        "anchor": "Quantization and simulation of Born-Infeld non-linear electrodynamics on\n  a lattice: Born-Infeld non-linear electrodynamics arises naturally as a field theory\ndescription of the dynamics of strings and branes. Most analyses of this theory\nhave been limited to studying it as a classical field theory. We quantize this\ntheory on a Euclidean 4-dimensional space-time lattice and determine its\nproperties using Monte-Carlo simulations. The electromagnetic field around a\nstatic point charge is measured using Luscher-Weisz methods to overcome the\nsign problem associated with the introduction of this charge. The D field\nappears identical to that of Maxwell QED. However, the E field is enhanced by\nquantum fluctuations, while still showing the short distance screening observed\nin the classical theory. In addition, whereas for the classical theory, the\nscreening increases without bound as the non-linearity increases, the quantum\ntheory approaches a limiting conformal field theory.",
        "positive": "Behaviour of the topological susceptibility in two colour QCD across the\n  finite density transition: The behaviour of the topological susceptibility \\chi in QCD with two colours\nand 8 flavours of quarks is studied at nonzero temperature on the lattice\nacross the finite density transition. It is shown that the signal of \\chi drops\nabruptly at a critical chemical potential \\mu_c, much as it happens at the\nfinite temperature and zero density transition. The Polyakov loop and the\nchiral condensate undergo their transitions at the same critical value \\mu_c.\nAt a value \\mu_s of the chemical potential, called saturation point, which in\nour case satisfies \\mu_s > \\mu_c, Pauli blocking supervenes and consequently\nthe theory becomes quenched."
    },
    {
        "anchor": "Laplacian Abelian Projection: A new partial gauge fixing condition for the abelian projection is\nintroduced. It is based on the lowest-lying eigenvector of a covariant\nLaplacian operator. This gauge is smooth and free of lattice Gribov copies.\nThese properties are important for an unambiguous computation of the abelian\nprojected gauge field configuration.",
        "positive": "The QCD spectrum with three quark flavors: We present results from a lattice hadron spectrum calculation using three\nflavors of dynamical quarks - two light and one strange, and quenched\nsimulations for comparison. These simulations were done using a one-loop\nSymanzik improved gauge action and an improved Kogut-Susskind quark action. The\nlattice spacings, and hence also the physical volumes, were tuned to be the\nsame in all the runs to better expose differences due to flavor number. Lattice\nspacings were tuned using the static quark potential, so as a byproduct we\nobtain updated results for the effect of sea quarks on the static quark\npotential. We find indications that the full QCD meson spectrum is in better\nagreement with experiment than the quenched spectrum. For the 0++ (a0) meson we\nsee a coupling to two pseudoscalar mesons, or a meson decay on the lattice."
    },
    {
        "anchor": "Volume reduction through perturbative Wilson loops: We derive the perturbative expansion of Wilson loops to order g^4 in a SU(N)\nlattice gauge theory with twisted boundary conditions. Our expressions show\nthat the thermodynamic limit is attained at infinite N for any number of\nlattice sites and allow to quantify the deviations from volume independence at\nfinite large N as a function of the twist.",
        "positive": "Quenched QCD at finite temperature with chiral Fermions: We study physics at temperatures just above the QCD phase transition (Tc)\nusing chiral (overlap) Fermions in the quenched approximation of lattice QCD.\nExact zero modes of the overlap Dirac operator are localized and their\nfrequency of occurrence drops with temperature. This is closely related to\naxial U(1) symmetry, which remains broken up to 2Tc. After subtracting the\neffects of these zero modes, chiral symmetry is restored, as indicated by the\nbehavior of the chiral condensate. The pseudoscalar and vector screening masses\nare close to ideal gas values."
    },
    {
        "anchor": "Glueball scattering cross section in lattice SU(2) Yang-Mills theory: We calculate the scattering cross section between two $0^{++}$ glueballs in\n$SU(2)$ Yang-Mills theory on lattice at $\\beta = 2.1, 2.2, 2.3, 2.4$, and 2.5\nusing the indirect (HAL QCD) method. We employ the cluster-decomposition error\nreduction technique and use all space-time symmetries to improve the signal. In\nthe use of the HAL QCD method, the centrifugal force was subtracted to remove\nthe systematic effect due to nonzero angular momenta of lattice discretization.\nFrom the extracted interglueball potential we determine the low energy glueball\neffective theory by matching with the one-glueball exchange process. We then\ncalculate the scattering phase shift, and derive the relation between the\ninterglueball cross section and the scale parameter $\\Lambda$ as $\\sigma_{\\phi\n\\phi} = (2 - 51) \\Lambda^{-2}$ (stat.+sys.). From the observational constraints\nof galactic collisions, we obtain the lower bound of the scale parameter, as\n$\\Lambda > 60$ MeV. We also discuss the naturalness of the Yang-Mills theory as\nthe theory explaining dark matter.",
        "positive": "Chiral Gauge Theories and Fermion-Higgs Systems: Summary talk presented at the Conference on Lattice Field Theory, Amsterdam,\nSeptember, 1992. Abstract: The status of several proposals for defining a\ntheory of chiral fermions on the lattice is reviewed and some new estimates for\nthe upper bound on the Higgs mass are presented."
    },
    {
        "anchor": "Charged pion electric polarizability from lattice QCD: We present a calculation of the charged pion electric polarizability using\nthe background field method. To extract the mass-shift induced by the electric\nfield for the accelerated charged particle we fit the lattice QCD correlators\nusing correlators derived from an effective model. The methodology outlined in\nthis study (boundary conditions, fitting procedure, etc.) is designed to ensure\nthat the results are invariant under gauge transformations of the background\nfield. We apply the method to four $N_f=2$ dynamical ensembles to extract\n$\\alpha_{\\pi^\\pm}$ at pion mass of $315$ MeV.",
        "positive": "Running coupling in SU(2) gauge theory with two adjoint fermions: We study SU(2) gauge theory with two Dirac fermions in the adjoint\nrepresentation of the gauge group on the lattice. Using clover improved Wilson\nfermion action with hypercubic truncated stout smearing we perform simulations\nat larger coupling than earlier. We measure the evolution of the coupling\nconstant using the step scaling method with Schr\\\"odinger functional and study\nthe remaining discretization effects. At weak coupling we observe significant\ndiscretization effects, which make it difficult to obtain a fully controlled\ncontinuum limit. Nevertheless, the data remains consistent with the existence\nof a fixed point in the interval $2.2\\lesssim g^{\\ast 2}\\lesssim 3$. We also\nmeasure the anomalous dimension and find its value at the fixed point is\n$\\gamma^\\ast\\simeq 0.2\\pm 0.03$."
    },
    {
        "anchor": "Correlations and fluctuations from lattice QCD: We present the new results of the Wuppertal-Budapest lattice QCD\ncollaboration on flavor diagonal and non-diagonal quark number susceptibilities\nwith 2+1 staggered quark flavors, in a temperature regime between 120 and 400\nMeV. A Symanzik improved gauge and a stout-link improved staggered fermion\naction is utilized; the light and strange quark masses are set to their\nphysical values. Lattices with $N_t=6, 8, 10, 12$ are used. We perform a\ncontinuum extrapolation of those observables for which the scaling regime is\nreached, and discretization errors are under control.",
        "positive": "Hadron Scattering in an Asymmetric Box: We propose to study hadron-hadron scattering using lattice QCD in an\nasymmetric box which allows one to access more non-degenerate low-momentum\nmodes for a given volume. The conventional L\\\"{u}scher's formula applicable in\na symmetric box is modified accordingly. To illustrate the feasibility of this\napproach, pion-pion elastic scattering phase shifts in the I=2, J=0 channel are\ncalculated within quenched approximation using improved gauge and Wilson\nfermion actions on anisotropic lattices in an asymmetric box. After the chiral\nand continuum extrapolation, we find that our quenched results for the\nscattering phase shifts in this channel are consistent with the experimental\ndata when the three-momentum of the pion is below 300MeV. Agreement is also\nfound when compared with previous theoretical results from lattice and other\nmeans. Moreover, with the usage of asymmetric volume, we are able to compute\nthe scattering phases in the low-momentum range (pion three momentum less than\nabout 350MeV in the center of mass frame) for over a dozen values of the pion\nthree-momenta, much more than using the conventional symmetric box with\ncomparable volume."
    },
    {
        "anchor": "Chiral extrapolation of lattice moments of proton quark distributions: We present the resolution of a long-standing discrepancy between the moments\nof parton distributions calculated from lattice QCD and their experimental\nvalues. We propose a simple extrapolation formula for the moments of the\nnonsinglet quark distribution u-d, as a function of quark mass, which embodies\nthe general constraints imposed by the chiral symmetry of QCD. The inclusion of\nthe leading nonanalytic behavior leads to an excellent description of both the\nlattice data and the experimental values of the moments.",
        "positive": "Effective Chiral Lagrangians and Lattice QCD: We propose a general method to obtain accurate estimates for some of the\n\"low-energy constants\" in the one-loop effective chiral Lagrangian by means of\nsimulating lattice QCD. In particular, the method is sensitive to those\nconstants whose values are required to test the hypothesis of a massless\nup-quark. Initial tests performed in the quenched approximation confirm that\ngood statistical precision can be achieved. As a byproduct we obtain an\naccurate estimate for the ratio of pseudoscalar decay constants, F_K/F_pi, in\nthe quenched approximation, which lies 10% below the experimental result. The\nquantities that serve to extract the low-energy constants also allow a test of\nthe scaling behaviour of different discretizations of QCD and a search for the\neffects of dynamical quarks."
    },
    {
        "anchor": "Chiral Properties of Strong Interactions in a Magnetic Background: We investigate the chiral properties of QCD in presence of a magnetic\nbackground field and in the low temperature regime, by lattice numerical\nsimulations of N_f = 2 QCD. We adopt a standard staggered discretization, with\na pion mass around 200 MeV, and explore a range of magnetic fields (180 MeV)^2\n\\leq|e|B \\leq (700 MeV)^2, in which we study magnetic catalysis, i.e. the\nincrease of chiral symmetry breaking induced by the background field. We\ndetermine the dependence of the chiral condensate on the external field,\ncompare our results with existing model predictions and show that a substantial\ncontribution to magnetic catalysis comes from the modified distribution of\nnon-Abelian gauge fields, induced by the magnetic field via dynamical quark\nloop effects.",
        "positive": "The muon anomalous magnetic moment, a view from the lattice: We review some of the issues that arise in attempts to compute the hadronic\ncorrections to the muon anomalous magnetic moment using Lattice QCD. We\nconcentrate on the dominant contribution, which requires an accurate evaluation\nof the hadronic vacuum polarization."
    },
    {
        "anchor": "Wave Functions and Spectrum in Hot Electroweak Matter for Large Higgs\n  Masses: We present results for the wave functions and the screening mass spectrum for\nquantum numbers $0^{++}$, $1^{--}$ and $2^{++}$ in the three-dimensional\nSU(2)-Higgs model near to the phase transition line below the endpoint and in\nthe crossover region. Varying the 3D gauge couplings we study the behaviour\nalong a line of constant physics towards the continuum limit in both phases. In\nthe crossover region the changing spectrum of screening states versus\ntemperature is examined showing the aftermath of the phase transition at lower\nHiggs mass. Different to smearing concepts we used large sets of operators with\nvarious extensions allowing to identify wave functions in position space.",
        "positive": "Non-Perturbative U(1) Gauge Theory at Finite Temperature: For compact U(1) lattice gauge theory (LGT) we have performed a finite size\nscaling analysis on $N_{\\tau} N_s^3$ lattices for $N_{\\tau}$ fixed by\nextrapolating spatial volumes of size $N_s\\le 18$ to $N_s\\to\\infty$. Within the\nnumerical accuracy of the thus obtained fits we find for $N_{\\tau}=4$, 5 and~6\nsecond order critical exponents, which exhibit no obvious $N_{\\tau}$\ndependence. The exponents are consistent with 3d Gaussian values, but not with\neither first order transitions or the universality class of the 3d XY model. As\nthe 3d Gaussian fixed point is known to be unstable, the scenario of a yet\nunidentified non-trivial fixed point close to the 3d Gaussian emerges as one of\nthe possible explanations."
    },
    {
        "anchor": "The Svetitsky-Yaffe conjecture for the plaquette operator: According to the Svetitsky-Yaffe conjecture, a (d+1)-dimensional pure gauge\ntheory undergoing a continuous deconfinement transition is in the same\nuniversality class as a d-dimensional statistical model with order parameter\ntaking values in the center of the gauge group. We show that the plaquette\noperator of the gauge theory is mapped into the energy operator of the\nstatistical model. For d=2, this identification allows us to use conformal\nfield theory techniques to evaluate exactly the correlation functions of the\nplaquette operator at the critical point. In particular, we can evaluate\nexactly the plaquette expectation value in presence of static sources, which\ngives some new insight in the structure of the color flux tube in mesons and\nbaryons.",
        "positive": "Curvature of the pseudocritical line in (2+1)-flavor QCD with HISQ\n  fermions: We study QCD with (2+1)-HISQ fermions at nonzero temperature and nonzero\nimaginary baryon chemical potential. Monte Carlo simulations are performed\nusing the MILC code along the line of constant physics with a light to strange\nmass ratio of $m_l/m_s=1/20$ on lattices up to $48^3 \\times 12$ to check for\nfinite cutoff effects. We determine the curvature of the pseudocritical line\nextrapolated to the continuum limit."
    },
    {
        "anchor": "Physics from the lattice: glueballs in QCD; topology; SU(N) for all N: Lectures given at the Isaac Newton Institute, NATO-ASI School on\n\"Confinement, Duality and Non-Perturbative Aspects of QCD\", 23 June - 4 July,\n1997.",
        "positive": "Computation of the chiral condensate using $N_f=2$ and $N_f=2+1+1$\n  dynamical flavors of twisted mass fermions: We apply the spectral projector method, recently introduced by Giusti and\nL\\\"uscher, to compute the chiral condensate using $N_f=2$ and $N_f=2+1+1$\ndynamical flavors of maximally twisted mass fermions. We present our results\nfor several quark masses at three different lattice spacings which allows us to\nperform the chiral and continuum extrapolations. In addition we report our\nanalysis on the $O(a)$ improvement of the chiral condensate for twisted mass\nfermions. We also study the effect of the dynamical strange and charm quarks by\ncomparing our results for $N_f=2$ and $N_f=2+1+1$ dynamical flavors."
    },
    {
        "anchor": "Infrared Abelian Dominance and Dual Higgs Mechanism in Maximally Abelian\n  Gauge: We study infrared abelian dominance and the dual Higgs mechanism in the\nmaximally abelian (MA) gauge using the lattice QCD Monte Carlo simulation. In\nthe MA gauge, the off-diagonal gluon phase tends to be random, and the\noff-diagonal gluon $A_\\mu^\\pm$ acquires the effective mass as $M_{\\rm off}\n\\simeq$ 1.2 GeV. From the monopole current in the MA gauge, we extract the dual\ngluon field $B_\\mu$ and estimate the dual gluon mass as $m_B \\simeq $ 0.5 GeV.\nThe QCD-monopole structure is also investigated in terms of off-diagonal\ngluons. From the lattice QCD in the MA gauge, the dual Ginzburg-Landau (DGL)\ntheory can be constructed as a realistic infrared effective theory based on\nQCD.",
        "positive": "Evidence for layered symmetry breaking in SU(2) lattice gauge theory: Simulations of four-dimensional SU(2) lattice gauge theory are performed with\npartial axial gauge fixing trees spanning three of the four dimensions. The\nremaining SU(2) gauge symmetry, global in three directions and local in one, is\nfound to break spontaneously at weak coupling, with the average\nfourth-dimension-pointing link in each perpendicular hyperplane as order\nparameter. The symmetry is restored at strong coupling. Symmetry breaking in\neach hyperplane appears to be independent, and occurs regardless of boundary\nconditions. The associated phase transition is likely coincident with the\nPolyakov loop transition."
    },
    {
        "anchor": "Scaling of Pseudo-Critical Couplings in Two-Flavour QCD: We study the scaling behaviour of the pseudo-critical couplings for the\nchiral phase transition in two-flavour QCD. We show that all existing results\nfrom lattice simulations on lattices with temporal extent $N_\\tau = 4$, 6 and 8\ncan be mapped onto a universal scaling curve. The relevant combination of\ncritical exponents, $\\beta\\delta$, is consistent with the scaling behaviour\nexpected for a second order phase transition with $O(4)$ exponents. At present,\nscaling according to the $O(2)$ symmetry group can, however, not be ruled out.",
        "positive": "Dynamical Fermion on Random-Block Lattice: Massless fermion field interacting with abelian dynamical gauge field on\n2-dimensional random-block lattices are investigated using Hybrid Monte Carlo\nsimulations. Preliminary results of the Wilson loop and the chiral correlation\nfunction are in agreement with the continuum Schwinger model."
    },
    {
        "anchor": "Deriving exact results for Ising-like models from the cluster variation\n  method: The cluster variation method (CVM) is an approximation technique which\ngeneralizes the mean field approximation and has been widely applied in the\nlast decades, mainly for finding accurate phase diagrams of Ising-like lattice\nmodels. Here we discuss in which cases the CVM can yield exact results,\nconsidering: (i) one-dimensional systems and strips (in which case the method\nreduces to the transfer matrix method), (ii) tree-like lattices and (iii) the\nso-called disorder points of euclidean lattice models with competitive\ninteractions in more than one dimension.",
        "positive": "From lattice QCD to predictions of scattering phase shifts at the\n  physical point: The Hadron Spectrum Collaboration (HSC) presented new results on two of their\nensembles for s-wave scattering phase shifts in the open-charm sector of QCD.\nFor such ensembles we have made predictions that are based on the chiral\nLagrangian that were published two years ago. In this talk we confront our\nphase shifts with those of HSC. A remarkably consistent picture emerges. In\nparticular there is mounting evidence for the existence of a flavor-sextet\nstate in the $D \\pi$ and $D^*\\pi$ channels, that show a striking quark-mass\ndependence."
    },
    {
        "anchor": "Thermal dilepton rates from quenched lattice QCD: We present new lattice results on the continuum extrapolation of the vector\ncurrent correlation function. Lattice calculations have been carried out in the\ndeconfined phase at a temperature of 1.1 Tc, extending our previous results at\n1.45 Tc, utilizing quenched non-perturbatively clover-improved Wilson fermions\nand light quark masses. A systematic analysis on multiple lattice spacings\nallows to perform the continuum limit of the correlation function and to\nextract spectral properties in the continuum limit.\n  Our current analysis suggests the results for the electrical conductivity are\nproportional to the temperature and the thermal dilepton rates in the quark\ngluon plasma are comparable for both temperatures. Preliminary results of the\ncontinuum extrapolated correlation function at finite momenta, which relates to\nthermal photon rates, are also presented.",
        "positive": "Renormalization Group Analysis of Lattice Theories and Improved Lattice\n  Action. II -- four-dimensional non-abelian SU(N) gauge model: A new block spin renormalization group transformation for SU(N) gauge models\nis proposed near the non-trivial fixed point in perturbation theory and thereby\nthe expectation values of various Wilson loops on the renormalized trajectory\nnear the fixed point are explicitly obtained. An improved action is obtained as\nin a preceding paper and a criterion for the scaling behavior of physical\nquantities is also given."
    },
    {
        "anchor": "$B_s \\rightarrow D_s^*$ Form Factors for the full $q^2$ range from\n  Lattice QCD: We compute the Standard Model semileptonic vector and axial-vector form\nfactors for $B_s\\to D_s^*$ decay across the full $q^2$ range using lattice QCD.\nWe use the Highly Improved Staggered Quark (HISQ) action for all valence\nquarks, enabling us to normalise weak currents nonperturbatively. We use gluon\nfield configurations including $u$, $d$, $s$ and $c$ HISQ sea quarks and\nmultiple HISQ heavy quarks with masses from the $c$ mass up to that of the $b$\non our finest lattices. We determine the physical form factors, with which we\nconstruct the differential and total rates for $\\Gamma(B_s^0\\to\nD_s^{*-}\\ell^+{\\nu}_\\ell)$. We find\n$\\Gamma_{\\ell=e}/|\\eta_\\mathrm{EW}V_{cb}|^2=2.07(17)_\\mathrm{latt}(2)_\\mathrm{EM}\\times\n10^{13} ~\\mathrm{s}^{-1}$,\n$\\Gamma_{\\ell=\\mu}/|\\eta_\\mathrm{EW}V_{cb}|^2=2.06(16)_\\mathrm{latt}(2)_\\mathrm{EM}\\times\n10^{13} ~\\mathrm{s}^{-1}$ and\n$\\Gamma_{\\ell=\\tau}/|\\eta_\\mathrm{EW}V_{cb}|^2=5.14(37)_\\mathrm{latt}(5)_\\mathrm{EM}\\times\n10^{12} ~\\mathrm{s}^{-1}$, where $\\eta_\\mathrm{EW}$ contains the electroweak\ncorrection to $G_F$, the first uncertainty is from our lattice calculation, and\nthe second allows for long-distance QED effects. We compute the ratio\n$R(D_s^{*-})\\equiv\n\\Gamma_{\\ell=\\tau}/\\Gamma_{\\ell=\\mu}=0.2490(60)_\\mathrm{latt}(35)_\\mathrm{EM}$\nand obtain a value for the ratio of decay rates $\\Gamma_{\\ell=\\mu}(B_s\\to\nD_s)/\\Gamma_{\\ell=\\mu}(B_s\\to D_s^*)=0.443(40)_\\mathrm{latt}(4)_\\mathrm{EM}$,\nwhich agrees well with recent LHCb results. We determine $|V_{cb}|=42.2\n(1.5)_\\mathrm{latt}(1.7)_\\mathrm{exp}(0.4)_\\mathrm{EM} \\times 10^{-3}$ by\ncombining our lattice results across the full q^2 range with experimental\nresults from LHCb. A comparison of our results to the normalised differential\ndecay rate from LHCb shows good agreement. We also test the impact of new\nphysics couplings on observables sensitive to lepton flavor universality\nviolation.",
        "positive": "The low-lying baryon spectrum with two dynamical twisted mass fermions: The masses of the low lying baryons are evaluated using two degenerate\nflavors of twisted mass sea quarks corresponding to pseudo scalar masses in the\nrange of about 270-500 MeV. The strange valence quark mass is tuned to\nreproduce the mass of the kaon in the physical limit. The tree-level Symanzik\nimproved gauge action is employed. We use lattices of spatial size 2.1 fm and\n2.7 fm at two values of the lattice spacing with $r_0/a=5.22(2)$ and\n$r_0/a=6.61(3)$. We check for both finite volume and cut-off effects on the\nbaryon masses. We performed a detailed study of the chiral extrapolation of the\noctet and decuplet masses using SU(2) $\\chi$PT. The lattice spacings determined\nusing the nucleon mass at the physical point are consistent with the values\nextracted using the pion decay constant. We examine the issue of isospin\nsymmetry breaking for the octet and decuplet baryons and its dependence on the\nlattice spacing. We show that in the continuum limit isospin breaking is\nconsistent with zero, as expected. The baryon masses that we find after taking\nthe continuum limit and extrapolating to the physical limit are in good\nagreement with experiment."
    },
    {
        "anchor": "Low-Temperature Series for Ising Model by Finite-Lattice Method: We have calculated the low-temperature series for the second moment of the\ncorrelation function in $d=3$ Ising model to order $u^{26}$ and for the free\nenergy of Absolute Value Solid-on-Solid (ASOS) model to order $u^{23}$, using\nthe finite-lattice method.",
        "positive": "Excited-Nucleon Spectroscopy with 2+1 Fermion Flavors: We present progress made by the Hadron Spectrum Collaboration (HSC) in\ndetermining the tower of excited nucleon states using 2+1-flavor anisotropic\nclover lattices. The HSC has been investigating interpolating operators\nprojected into irreducible representations of the cubic group in order to\nbetter calculate two-point correlators for nucleon spectroscopy; results are\npublished for quenched and 2-flavor anisotropic Wilson lattices. In this work,\nwe present the latest results using a new technique, distillation, which allows\nus to reach higher statistics than before. Future directions will be outlined\nat the end."
    },
    {
        "anchor": "Distance between configurations in Markov chain Monte Carlo simulations: For a given Markov chain Monte Carlo algorithm we introduce a distance\nbetween two configurations that quantifies the difficulty of transition from\none configuration to the other configuration. We argue that the distance takes\na universal form for the class of algorithms which generate local moves in the\nconfiguration space. We explicitly calculate the distance for the Langevin\nalgorithm, and show that it certainly has desired and expected properties as\ndistance. We further show that the distance for a multimodal distribution gets\ndramatically reduced from a large value by the introduction of a tempering\nmethod. We also argue that, when the original distribution is highly multimodal\nwith large number of degenerate vacua, an anti-de Sitter-like geometry\nnaturally emerges in the extended configuration space.",
        "positive": "Towards a Non-Perturbative Calculation of DIS Wilson Coefficients: We verify the operator product expansion (OPE) of deep inelastic scattering\n(DIS) on the lattice and present first results of a non-perturbative\ncalculation of the Wilson coefficients."
    },
    {
        "anchor": "Thermodynamics of Four-Flavour QCD with Improved Staggered Fermions: We have calculated the pressure and energy density in four-flavour QCD using\nimproved fermion and gauge actions. We observe a strong reduction of finite\ncut-off effects in the high temperature regime, similar to what has been noted\nbefore for the SU(3) gauge theory. Calculations have been performed on\n$16^3\\times 4$ and 16^4 lattices for two values of the quark mass, $ma = 0.05$\nand 0.1. A calculation of the string tension at zero temperature yields a\ncritical temperature $T_c/\\sqrt{\\sigma} = 0.407 \\pm 0.010$ for the smaller\nquark mass value.",
        "positive": "The static quark potential for dynamical domain wall fermion simulations: We present preliminary results for the static quark potential computed on\nsome of the DWF lattice configurations generated by the RBC-UKQCD\ncollaborations. Most of these results were obtained using Wilson lines joining\nspatial planes fixed into the Coulomb gauge. We compare the results from this\nmethod with the earlier ones on $16^3 \\times 32$ lattices using Bresenham\nspatial paths with APE smeared link variables. Some preliminary results on\n$24^3 \\times 64$ lattices are also presented."
    },
    {
        "anchor": "Momentum transfer dependence of kaon semileptonic form factor on (10\n  fm)$^4$ at the physical point: We calculate the kaon semileptonic form factors using the two sets of the\nPACS10 configuration, whose physical volumes are more than (10 fm)$^4$ at the\nphysical point. The lattice spacings are 0.063 and 0.085 fm. The configurations\nwere generated using the Iwasaki gauge action and $N_f=2+1$ stout-smeared\nnonperturbatively $O(a)$-improved Wilson quark action. From the momentum\ntransfer dependence of the form factors, we evaluate the slope and curvature\nfor the form factors at the zero momentum transfer. Furthermore, we calculate\nthe phase space factor, which is used to obtain $|V_{us}|$ through the kaon\nsemileptonic decay. These results are compared with previous lattice results\nand experimental values.",
        "positive": "Lattice QCD on upcoming Arm architectures: Recently Arm introduced a new instruction set called Scalable Vector\nExtension (SVE), which supports vector lengths up to 2048 bits. While SVE\nhardware will not be generally available until about 2021, we believe that\nfuture SVE-based architectures will have great potential for Lattice QCD. In\nthis contribution we discuss key aspects of SVE and describe how we implemented\nSVE in the Grid Lattice QCD framework."
    },
    {
        "anchor": "The $\u03be/\u03be_{2nd}$ ratio as a test for Effective Polyakov Loop Actions: Effective Polyakov line actions are a powerful tool to study the finite\ntemperature behaviour of lattice gauge theories. They are much simpler to\nsimulate than the original (3+1) dimensional LGTs and are affected by a milder\nsign problem. However it is not clear to which extent they really capture the\nrich spectrum of the original theories, a feature which is instead of great\nimportance if one aims to address the sign problem. We propose here a simple\nway to address this issue based on the so called second moment correlation\nlength $\\xi_{2nd}$. The ratio $\\xi/\\xi_{2nd}$ between the exponential\ncorrelation length and the second moment one is equal to 1 if only a single\nmass is present in the spectrum, and becomes larger and larger as the\ncomplexity of the spectrum increases. Since both $\\xi_{exp}$ and $\\xi_{2nd}$\nare easy to measure on the lattice, this is an economic and effective way to\nkeep track of the spectrum of the theory. In this respect we show using both\nnumerical simulation and effective string calculations that this ratio\nincreases dramatically as the temperature decreases. This non-trivial behaviour\nshould be reproduced by the Polyakov loop effective action.",
        "positive": "The rate of photon production in the quark-gluon plasma from lattice QCD: We calculate the thermal rate of real-photon production in the quark-gluon\nplasma at a temperature of $T=254$ MeV using lattice QCD. The calculation is\nbased on the difference between the spatially transverse and longitudinal parts\nof the polarization tensor, which has the advantage of falling off rapidly at\nlarge frequencies. We obtain this linear combination in the time-momentum\nrepresentation from lattice QCD with two flavors of quarks in the continuum\nlimit with a precision of about two parts per mille. Applying a theoretically\nmotivated fit ansatz for the associated spectral function, we obtain values for\nthe photon rate that are in line with QCD weak-coupling calculations; for\nphoton momenta $ 1.0\\leq k[{\\rm GeV}]\\leq 1.4$, our non-perturbative results\nconstrain the rate to be no larger than twice the weak-coupling prediction. We\nalso provide a physics interpretation of the electromagnetic spectral functions\nvalid for all frequencies and momenta."
    },
    {
        "anchor": "Lattice gauge theories in the presence of a linear gauge-symmetry\n  breaking: We study the effects of gauge-symmetry breaking (GSB) perturbations in\nthree-dimensional lattice gauge theories with scalar fields. We study this\nissue at transitions in which gauge correlations are not critical and the gauge\nsymmetry only selects the gauge-invariant scalar degrees of freedom that become\ncritical. A paradigmatic model in which this behavior is realized is the\nlattice CP(1) model or, more generally, the lattice Abelian-Higgs model with\ntwo-component complex scalar fields and compact gauge fields. We consider this\nmodel in the presence of a linear GSB perturbation. The gauge symmetry turns\nout to be quite robust with respect to the GSB perturbation: the continuum\nlimit is gauge-invariant also in the presence of a finite small GSB term. We\nalso determine the phase diagram of the model. It has one disordered phase and\ntwo phases that are tensor and vector ordered, respectively. They are separated\nby continuous transition lines, which belong to the O(3), O(4), and O(2) vector\nuniversality classes, and which meet at a multicritical point. We remark that\nthe behavior at the CP(1) gauge-symmetric critical point substantially differs\nfrom that at transitions in which gauge correlations become critical, for\ninstance at transitions in the noncompact lattice Abelian-Higgs model that are\ncontrolled by the charged fixed point: in this case the behavior is extremely\nsensitive to GSB perturbations.",
        "positive": "The U(1) Gross-Neveu Model at Non-Zero Chemical Potential: The four-fermi model with continuous chiral symmetry is studied in three\ndimensions at non-zero chemical potential $\\mu$ using both the $1/N_f$\nexpansion and computer simulations. For strong coupling this model\nspontaneously breaks its U(1) chiral symmetry at zero chemical potential and\nthe Goldstone mechanism is realized through massless pions. The computer\nsimulation predicts a critical chemical potential $\\mu_c$ close to the lightest\nfermion mass in the model. As $\\mu$ is increased beyond $\\mu_c$, the pion\nscreening mass increases rapidly from zero to a nonvanishing value indicating\nsymmetry restoration. Some lessons are drawn relevant to lattice QCD\nsimulations at non-zero $\\mu$."
    },
    {
        "anchor": "Species Doublers as Super Multiplet Partners in Lattice Supersymmetry: We propose a new lattice superfield formalism in momentum representation\nwhich accommodates species doublers of the lattice fermions and their bosonic\ncounterparts as super multiplets. We explicitly show that one dimensional $N=2$\nmodel with interactions has exact supersymmetry on the lattice for all super\ncharges with lattice momentum. In coordinate representation the finite\ndifference operator is made to satisfy Leibnitz rule by introducing a non local\nproduct, the \"star\" product, and the exact lattice supersymmetry is realized.\nSupersymmetric Ward identities are shown to be satisfied at one loop level.",
        "positive": "Physics From Breit-Frame Regularization Of a Lattice Hamiltonian: We suggest a Hamiltonian formulation on a momentum lattice using a physically\nmotivated regularization using the Breit-frame which links the maximal parton\nnumber to the lattice size. This scheme restricts parton momenta to positive\nvalues in each spatial direction. This leads to a drastic reduction of degrees\nof freedom compared to a regularization in the rest frame (center at zero\nmomentum). We discuss the computation of physical observables like (i) mass\nspectrum in the critical region, (ii) structure and distribution functions,\n(iii) $S$-matrix, (iv) finite temperature and finite density thermodynamics in\nthe Breit-frame regularization. For the scalar $\\phi^{4}_{3+1}$ theory we\npresent numerical results for the mass spectrum in the critical region. We\nobserve scaling behavior for the mass of the ground state and for some higher\nlying states. We compare our results with renormalization group results by\nL\\\"uscher and Weisz. Using the Breit-frame, we calculate for $QCD$ the relation\nbetween the $W^{\\mu \\nu}$ tensor, structure functions (polarized and\nunpolarized) and quark distribution functions. We use the improved parton-model\nwith a scale dependence and take into account a non-zero parton mass. In the\nBjorken limes we find the standard relations between $F_{1}$, $F_{2}$, $g_{1}$\nand the quark distribution functions. We discuss the r\\^ole of helicity. We\npresent numerical results for parton distribution functions in the scalar\nmodel. For the $\\phi^{4}$-model we find no bound state with internal parton\nstructure. For the $\\phi^{3}$-model we find a distribution function with parton\nstructure similar to Altarelli-Parisi behavior of $QCD$."
    },
    {
        "anchor": "Recent progress in applying lattice QCD to kaon physics: Standard lattice calculations in kaon physics are based on the evaluation of\nmatrix elements of local operators between two single-hadron states or a\nsingle-hadron state and the vacuum. Recent progress in lattice QCD has gone\nbeyond these standard observables. I will review the status and prospects of\nlattice kaon physics with an emphasis on non-leptonic $K\\to\\pi\\pi$ decay and\nlong-distance processes including $K^0$-$\\overline{K^0}$ mixing and rare kaon\ndecays.",
        "positive": "The fluctuational region on the phase diagram of lattice Weinberg -\n  Salam model: The lattice Weinberg - Salam model without fermions is investigated\nnumerically for the realistic choice of bare coupling constants correspondent\nto the value of the Weinberg angle $\\theta_W \\sim 30^o$, and the fine structure\nconstant $\\alpha \\sim {1/100}$. On the phase diagram there exists the vicinity\nof the phase transition between the physical Higgs phase and the unphysical\nsymmetric phase, where the fluctuations of the scalar field become strong. The\nclassical Nambu monopole can be considered as an embryo of the unphysical\nsymmetric phase within the physical phase. In the fluctuational region quantum\nNambu monopoles are dense and, therefore, the perturbation expansion around\ntrivial vacuum cannot be applied. The maximal value of the cutoff at the given\nvalues of coupling constants calculated using the lattices of sizes $8^3\\times\n16$, $12^3\\times 16$, and $16^4$ is $\\Lambda_c \\sim 1.4 \\pm 0.2$ Tev. As the\nlattice sizes used are rather small we consider this result as preliminary."
    },
    {
        "anchor": "Vortex induced confinement and the Kugo-Ojima confinement criterion: The SU(2) Yang-Mills gluon and ghost Green-functions are studied in Landau\ngauge by means of lattice gauge simulations. A focal point is their low energy\nbehavior since in particular the Kugo-Ojima confinement criterion relates a\ndiverging ghost form factor at vanishing momentum transfer to the confining\ncapabilities of the theory. This divergence is verified by numerical\nsimulations. Removing the confining vortices from the lattice ensembles\nconverts SU(2) Yang-Mills theory in a non-confining theory. It is shown that in\nthis modified theory the divergence of the ghost propagator disappears.",
        "positive": "MRHS multigrid solver for Wilson-clover fermions: We describe our implementation of a multigrid solver for Wilson-clover\nfermions, which increases parallelism by solving for multiple right-hand sides\n(MRHS) simultaneously. The solver is based on Grid and thus runs on all\ncomputing architectures supported by the Grid framework. We present detailed\nbenchmarks of the relevant kernels, such as hopping and clover term on the\nvarious multigrid levels, intergrid operators, and reductions. The benchmarks\nwere performed on the JUWELS Booster system at J\\\"ulich Supercomputing Centre,\nwhich is based on Nvidia A100 GPUs. For example, solving a $24^3\\times128$\nlattice on 16 GPUs, the overall speedup obtained solely from MRHS is about 10x."
    },
    {
        "anchor": "Confinement-Deconfinement transition in $SU(2)+$Higgs Theory: We study the confinement-deconfinement transition in $SU(2)$ gauge theory in\nthe presence of massless bosons using lattice Monte Carlo simulations. The\nnature of this transition depends on the temporal extent ($N_\\tau$) of the\nEuclidean lattice. We find that the transition is a cross-over for $N_\\tau=2,4$\nand second order with $3D$ Ising universality class for $N_\\tau=8$. Our results\nshow that the second order transition is accompanied by realization of the\n$Z_2$ symmetry.",
        "positive": "Entanglement Entropy due to the Presence of Static Quarks: We study the entanglement of gluon fields in presence of a static $Q\\bar Q$\npair in quenched QCD. Using the replica method, we investigate the $q=2$ Renyi\nentropy of the entanglement of gluon fields inside and in the vicinity of the\nconfining QCD string between the quark and the antiquark. We find that there is\nexcess entropy of gluon entanglement compared to vacuum fluctuations. This\nexcess of entanglement entropy is associated with the gluon flux tube, and we\nfind that it has a finite non-zero value in the continuum. We investigate the\ndependence of gluon entanglement on the geometry of longitudinal and transverse\npartitioning of the flux tube. Our preliminary results suggest scaling of the\nentanglement entropy with the area of the boundary overlapping with the flux\ntube."
    },
    {
        "anchor": "Applications of Chiral Perturbation theory to lattice QCD: These lectures describe the use of effective field theories to extrapolate\nresults from the parameter region where numerical simulations of lattice QCD\nare possible to the physical parameters (physical quark masses, infinite\nvolume, vanishing lattice spacing, etc.). After a brief introduction and\noverview, I discuss three topics: 1) Chiral perturbation theory in the\ncontinuum; 2) The inclusion of discretization effects into chiral perturbation\ntheory, focusing on the application to Wilson and twisted-mass lattice\nfermions; 3) Extending chiral perturbation theory to describe partially\nquenched QCD.",
        "positive": "A lattice estimate of the g_{D^* D pi} coupling: We present the results of the first direct determination of the g_{D^* D pi}\ncoupling using lattice QCD. From our simulations in the quenched approximation,\nwe obtain g_{D^* D pi} = 18.8 +/- 2.3^{+1.1}_{-2.0} and hat(g) = 0.67 +/-\n0.08^{+0.04}_{-0.06}. It is in agreement with a recent experimental result from\nCLEO."
    },
    {
        "anchor": "On the Spectrum of Lattice Dirac Operators: With the Schwinger model as example I discuss properties of lattice Dirac\noperators, with some emphasis on Monte Carlo results for topological charge,\nchiral fermions and eigenvalue spectra.",
        "positive": "Thimble regularization at work: from toy models to chiral random matrix\n  theories: We apply the Lefschetz thimble formulation of field theories to a couple of\ndifferent problems. We first address the solution of a complex 0-dimensional\nphi^4 theory. Although very simple, this toy-model makes us appreciate a few\nkey issues of the method. In particular, we will solve the model by a correct\naccounting of all the thimbles giving a contribution to the partition function\nand we will discuss a number of algorithmic solutions to simulate this (simple)\nmodel. We will then move to a chiral random matrix (CRM) theory. This is a\nsomehow more realistic setting, giving us once again the chance to tackle the\nsame couple of fundamental questions: how many thimbles contribute to the\nsolution? how can we make sure that we correctly sample configurations on the\nthimble? Since the exact result is known for the observable we study (a\ncondensate), we can verify that, in the region of parameters we studied, only\none thimble contributes and that the algorithmic solution that we set up works\nwell, despite its very crude nature. The deviation of results from phase\nquenched results highlights that in a certain region of parameter space there\nis a quite important sign problem. In view of this, the success of our thimble\napproach is quite a significant one."
    },
    {
        "anchor": "Investigation of the Perturbative Expansion of Moments of Heavy Quark\n  Correlators for $N_f=0$: The QCD-coupling is a necessary input in the computation of many observables,\nand the parametric error on input parameters can be a dominant source of\nuncertainty. The coupling can be extracted by comparing high order perturbative\ncomputations and lattice evaluated moments of mesonic two-point functions with\nheavy quarks, which provide a high energy scale for perturbation theory. The\ntruncation of the perturbative series is an important systematic uncertainty.\nWe report on our attempt to study this issue by measuring pseudo-scalar\ntwo-point functions in volumes of $L=2\\, \\text{fm}$ with twisted-mass Wilson\nfermions in the quenched approximation. We use full twist, the non-perturbative\nclover term and lattice spacings down to $a=0.015\\,\\text{fm}$ to tame the\nsizable discretization effects. Our preliminary results indicate that either\nhigher order perturbative corrections or the continuum limit are not under\nsufficient control despite our small lattice spacings and quark masses\nextending beyond $2\\,m_{\\text{charm}}$.",
        "positive": "Reply to Isgur's Comments on Valence QCD: We reply to Nathan Isgur's critique that is directed at some of the\nconclusions drawn from the lattice simulation of valence QCD, regarding the\nvalence quark model and effective chiral theories."
    },
    {
        "anchor": "Light-cone Distribution Amplitudes of the Nucleon and Negative Parity\n  Nucleon Resonances from Lattice QCD: We present the results of a lattice study of light-cone distribution\namplitudes (DAs) of the nucleon and negative parity nucleon resonances using\ntwo flavors of dynamical (clover) fermions on lattices of different volumes and\npion masses down to m_pi = 150 MeV. We find that the three valence quarks in\nthe proton share their momentum in the proportion 37% : 31% : 31%, where the\nlarger fraction corresponds to the u-quark that carries proton helicity, and\ndetermine the value of the wave function at the origin in position space, which\nturns out to be small compared to the existing estimates based on QCD sum\nrules. Higher-order moments are constrained by our data and are all compatible\nwith zero within our uncertainties. We also calculate the normalization\nconstants of the higher-twist DAs that are related to the distribution of quark\nangular momentum. Furthermore, we use the variational method and customized\nparity projection operators to study the states with negative parity. In this\nway we are able to separate the contributions of the two lowest states that, as\nwe argue, possibly correspond to N*(1535) and a mixture of N*(1650) and the\npion-nucleon continuum, respectively. It turns out that the state that we\nidentify with N*(1535) has a very different DA as compared to both the second\nobserved negative parity state and the nucleon, which may explain the\ndifference in the decay patterns of N*(1535) and N*(1650) observed in\nexperiment.",
        "positive": "Fermionic Spectrum on General Dimensional Hyperdiamond Lattice: Withdrawn: replaced by e-Print: arXiv:0907.3774"
    },
    {
        "anchor": "D -> \u03c0l \u03bdand D -> K l \u03bdform factors with Nf=2+1+1 Twisted\n  fermions: We present a lattice QCD determination of the vector and scalar form factors\nof the semileptonic decays D->\\pi l \\nu and D -> K l \\nu which are relevant for\nthe extraction of the CKM matrix elements |Vcd| and |Vcs| from experimental\ndata. Our analysis is based on the gauge configurations produced by the\nEuropean Twisted Mass Collaboration with Nf = 2+1+1 dynamical fermions. We\nsimulated at three different values of the lattice spacing and with pion masses\nas small as 210 MeV. Our preliminary estimates for the vector form factor at\nzero 4-momentum transfer are f+(D -> \\pi)(0) = 0.610 (23) and f+(D -> K)(0) =\n0.747 (22), where the uncertainties are only statistical. By combining our\nresults with the experimental values of f+(D -> \\pi)(0) |Vcd| and f+(D -> K)(0)\n|Vcs| we obtain |Vcd| = 0.2336 (93) and |Vcs| = 0.975 (30), which together with\nthe PDG determination of |Vcb| are in agreement with the unitarity constraint\nof the Standard Model.",
        "positive": "Penta-quark in Anisotropic Lattice QCD: Penta-quark (5Q) baryons are studied using anisotropic lattice QCD for\nhigh-precision measurement of temporal correlators. A non-NK-type interpolating\nfield is employed to study the 5Q states with J^P=1/2^{\\pm} and I=0. In\nJ^P=1/2^+ channel, the lowest-lying state is found at m_{5Q} \\simeq 2.25 GeV,\nwhich is too massive to be identified as the Theta^+(1540). In J^P=1/2^-\nchannel, the lowest-lying state is found at m_{5Q} \\simeq 1.75 GeV. To\ndistinguish a compact 5Q resonance state from an NK scattering state, a new\nmethod with ``hybrid boundary condition (HBC)'' is proposed. As a result of the\nHBC analysis, the observed state in the negative-parity channel turns out to be\nan $NK$ scattering state."
    },
    {
        "anchor": "Lattice Fermions Based on Higher-Dimensional Hyperdiamond Lattices: In this paper we generalize to higher dimensions several types of fermion\nactions on the hyperdiamond lattice including a two-parameter class of\nminimal-doubling fermions \"Creutz fermion\" and a simple fermion with sufficient\ndiscrete symmetry \"BBTW fermion\". Then it is shown that they possess some\nproperties in common with the four-dimensional case: BBTW fermions in higher\neven dimensions inevitably yield unphysical degrees of freedom. Creutz fermions\nare defined on the distorted lattices, and they lose the high discrete symmetry\nof the original lattices. We also find properties specific to the\nhigher-dimensional cases. The parameter range for Creutz action to yield\nminimal-doubling and physical fermions becomes narrower with the dimension\ngetting higher, thus it becomes more and more difficult to realize\nminimal-doubling. In addition, we generalize the subspecies of Creutz and BBTW\nactions including a new class of minimal-doubling actions \"Appended Creutz\naction\".",
        "positive": "Low temperature expansion of the gonihedric Ising model: We investigate a model of closed $(d-1)$-dimensional soft-self-avoiding\nrandom surfaces on a $d$-dimensional cubic lattice. The energy of a surface\nconfiguration is given by $E=J(n_{2}+4k n_{4})$, where $n_{2}$ is the number of\nedges, where two plaquettes meet at a right angle and $n_{4}$ is the number of\nedges, where 4 plaquettes meet. This model can be represented as a\n$\\Z_{2}$-spin system with ferromagnetic nearest-neighbour-, antiferromagnetic\nnext-nearest-neighbour- and plaquette-interaction. It corresponds to a special\ncase of a general class of spin systems introduced by Wegner and Savvidy. Since\nthere is no term proportional to the surface area, the bare surface tension of\nthe model vanishes, in contrast to the ordinary Ising model. By a suitable\nadaption of Peierls argument, we prove the existence of infinitely many ordered\nlow temperature phases for the case $k=0$. A low temperature expansion of the\nfree energy in 3 dimensions up to order $x^{38}$ ($x={e}^{-\\beta J}$) shows,\nthat for $k>0$ only the ferromagnetic low temperature phases remain stable. An\nanalysis of low temperature expansions up to order $x^{44}$ for the\nmagnetization, susceptibility and specific heat in 3 dimensions yields critical\nexponents, which are in agreement with previous results."
    },
    {
        "anchor": "The running coupling from lattice gauge theory:: I discuss some calculations of the running coupling in SU($N$) gauge theories\nfrom lattice simulations, centering on the work of the UKQCD collaboration.\nThis talk is introductory in nature; full details have been published\nelsewhere.",
        "positive": "A path-integral representation of the free one-flavour staggered-fermion\n  determinant: Lattice fermion actions are constructed with path integrals which are\nequivalent to the free one-flavour staggered fermion determinant. The Dirac\noperators used are local and have an identical spectrum of states to the\nstaggered theory. Operators obeying a generalised Ginsparg-Wilson relation are\ndeveloped."
    },
    {
        "anchor": "Absence of bilinear condensate in three-dimensional QED: There are plausibility arguments that QED in three dimensions has a critical\nnumber of flavors of massless two-component fermions, below which scale\ninvariance is broken by the presence of bilinear condensate. We present\nnumerical evidences from our lattice simulations using dynamical overlap as\nwell as Wilson-Dirac fermions for the absence of bilinear condensate for any\neven number of flavors of two-component fermions. Instead, we find evidences\nfor the scale-invariant nature of three-dimensional QED.",
        "positive": "Strongly interacting dynamics and the search for new physics at the LHC: We present results for the spectrum of a strongly interacting SU(3) gauge\ntheory with $N_f = 8$ light fermions in the fundamental representation.\nCarrying out non-perturbative lattice calculations at the lightest masses and\nlargest volumes considered to date, we confirm the existence of a remarkably\nlight singlet scalar particle. We explore the rich resonance spectrum of the\n8-flavor theory in the context of the search for new physics beyond the\nstandard model at the Large Hadron Collider (LHC). Connecting our results to\nmodels of dynamical electroweak symmetry breaking, we estimate the vector\nresonance mass to be about 2 TeV with a width of roughly 450 GeV, and predict\nadditional resonances with masses below ~3 TeV."
    },
    {
        "anchor": "Large N and confining flux tubes as strings - a view from the lattice: I begin these three lectures by describing some of the useful things that we\nhave learned about large-N gauge theories using lattice simulations. For\nexample that the theory is confining in that limit, that for many quantities\nSU(3) is close to SU(oo), and that this includes the strongly coupled gluon\nplasma just above Tc, thus providing some of the justification needed to make\nuse of gauge-gravity duality in analysing QCD at RHIC/LHC temperatures. I then\nturn, in a more detailed discussion, to recent progress on the problem of what\neffective string theory describes confining flux tubes. I describe lattice\ncalculations of the energy spectrum of closed loops of confining flux, and some\ndramatic analytic progress in extending the `universal Luscher correction' to\nterms that are of higher order in 1/l, where l is the length of the string.\nBoth approaches point increasingly to the Nambu-Goto free string theory as\nbeing the appropriate starting point for describing string-like degrees of\nfreedom in SU(N) gauge theories.",
        "positive": "The Infrared Limit of the QCD Dirac Spectrum: The distribution of the low-lying QCD Dirac spectrum is analyzed by means of\npartial quenched chiral perturbation theory. We identify an energy scale below\nwhich the valence quark mass dependence of the QCD partition function is given\nby chiral Random Matrix Theory. This is the the domain where the low-energy QCD\npartition function is dominated by the fluctuations of the mass term of the\nGoldstone bosons. In mesoscopic physics this domain is known the ergodic domain\nand the corresponding energy scale is the Thouless energy."
    },
    {
        "anchor": "Hadron form factors using density-density correlators: Gauge invariant density-density correlators yield detailed information on\nhadron structure. Hadron deformation and form factors can be extracted for\nmomentum transfers up to about 6 GeV$^2$. We use stochastic techniques and\ndilution to compute the all to all propagator required for the exact evaluation\nof density-density correlators. We present first results for the pion form\nfactor.",
        "positive": "B Meson Semileptonic Form Factors from Unquenched Lattice QCD: The semileptonic process, B --> \\pi l \\nu, is studied via full QCD Lattice\nsimulations. We use unquenched gauge configurations generated by the MILC\ncollaboration. These include the effect of vacuum polarization from three quark\nflavors: the $s$ quark and two very light flavors ($u/d$) of variable mass\nallowing extrapolations to the physical chiral limit. We employ Nonrelativistic\nQCD to simulate the $b$ quark and a highly improved staggered quark action for\nthe light sea and valence quarks. We calculate the form factors $f_+(q^2)$ and\n$f_0(q^2)$ in the chiral limit for the range 16 GeV$^2 \\leq q^2 < q^2_{max}$\nand obtain $\\int^{q^2_{max}}_{16 GeV^2} [d\\Gamma/dq^2] dq^2 / |v_{ub}|^2 =\n1.46(35) ps^{-1}$. Combining this with a preliminary average by the Heavy\nFlavor Averaging Group (HFAG'05) of recent branching fraction data for\nexclusive B semileptonic decays from the BaBar, Belle and CLEO collaborations,\nleads to $|V_{ub}| = 4.22(30)(51) \\times 10^{-3}$. PLEASE NOTE APPENDIX B with\nan ERRATUM, to appear in Physical Review D, to the published version of this\ne-print (Phys.Rev.D 73, 074502 (2006)). Results for the form factor $f_+(q^2)$\nin the chiral limit have changed significantly. The last two sentences in this\nabstract should now read; \"We calculate the form factor $f_+(q^2)$ and\n$f_0(q^2)$ in the chiral limit for the range 16 Gev$^2 \\leq q^2 < q^2_{max}$\nand obtain $\\int^{q^2_{max}}_{16 GeV^2} [d\\Gamma/dq^2] dq^2 / |V_{ub}|^2 =\n2.07(57)ps^{-1}$. Combining this with a preliminary average by the Heavy Flavor\nAveragibg Group (HFAG'05) of recent branching fraction data for exclusive B\nsemileptonic decays from the BaBar, Belle and CLEO collaborations, leads to\n$|V_{ub}| = 3.55(25)(50) \\times 10^{-3}$.\""
    },
    {
        "anchor": "Topology and Low Lying Fermion Modes: Recent results concerning the relation of topology and low-lying fermion\nmodes are summarized.",
        "positive": "Scattering in the quenched approximation: We study, in the quenched approximation, Luescher's relation between pion\nscattering lengths and the finite-volume energy of two pions at rest. The\nquenched relation is drastically different from the full theory one; in\nparticular, ``enhanced finite-volume corrections\" of order $L^0=1$ and $L^{-2}$\noccur at one loop ($L$ is the linear size of the box), due to the special\nproperties of the $\\eta'$ in the quenched approximation. Numerical examples\nshow that the size of these effects can be substantial."
    },
    {
        "anchor": "Smeared quasidistributions in perturbation theory: Quasi and pseudo distributions provide a new approach to determining parton\ndistribution functions (PDFs) from first principles' calculations of quantum\nchromodynamics (QCD). Here I calculate the flavor nonsinglet unpolarized quasi\ndistribution at one loop in perturbation theory, using the gradient flow to\nremove ultraviolet divergences. I demonstrate that, as expected, the gradient\nflow does not change the infrared structure of the quasi distribution at one\nloop and use the results to match the smeared matrix elements to those in the\n$\\ms$ scheme. This matching calculation is required to relate numerical results\nobtained from nonperturbative lattice QCD computations to light-front PDFs\nextracted from global analyses of experimental data.",
        "positive": "Topological charge on the lattice: a field theoretical view of the\n  geometrical approach: We construct sequences of ``field theoretical'' (analytical) lattice\ntopological charge density operators which formally approach geometrical\ndefinitions in 2-d $CP^{N-1}$ models and 4-d $SU(N)$ Yang Mills theories. The\nanalysis of these sequences of operators suggests a new way of looking at the\ngeometrical method, showing that geometrical charges can be interpreted as\nlimits of sequences of field theoretical (analytical) operators. In\nperturbation theory renormalization effects formally tend to vanish along such\nsequences. But, since the perturbative expansion is asymptotic, this does not\nnecessarily lead to well behaved geometrical limits. It indeed leaves open the\npossibility that non-perturbative renormalizations survive."
    },
    {
        "anchor": "Determinant Calculations Using Random Walk Worldline Loops: We use statistical ensembles of worldline loops generated by random walk on\nhypercubic lattices to calculate matter determinants in background Yang-Mills\nfields.",
        "positive": "Recent Developments in $x$-dependent Structure Calculations: First principles calculations of the Bjorken-$x$ dependence of hadron\nstructure have been a long-standing challenge for lattice QCD. This year marks\na significant milestone: the first determinations of parton distribution\nfunctions, which capture the longitudinal momentum structure of fast-moving\nhadrons, at physical pion masses. Moreover, there has been significant progress\nin our understanding of the theoretical frameworks underpinning these\ncalculations, although not all sources of systematic uncertainty have been\nfully explored. I review the various approaches to extracting $x$-dependent\nhadron structure from lattice QCD and highlight recent results in both the\nmeson and baryon sectors."
    },
    {
        "anchor": "Exploring the QCD vacuum - (some) recent developments in confinement and\n  topology: I start by giving a brief overview over new developments in the area of\nconfinement and topology. As an example for the interrelations between\ntopological objects, instantons at finite temperature are discussed. Then I\nfocus on new insights into the structure of the QCD vacuum obtained through\nfiltering methods, in particular those based on decompositions w.r.t. fermionic\neigenmodes.",
        "positive": "Exploring the QCD phase diagram via reweighting from isospin chemical\n  potential: We investigate the QCD phase diagram for small values of baryon and strange\nquark chemical potentials from simulations at non-zero isospin chemical\npotential. Simulations at pure isospin chemical potential are not hindered by\nthe sign problem and pion condensation can be observed for sufficiently large\nisospin chemical potentials. We study how the related phase boundary evolves\nwith baryonic and strange chemical potentials via reweighting in quark chemical\npotentials and discuss our results. Furthermore, we propose and implement an\nalternative method to approach nonzero baryon (and strange quark) chemical\npotentials. This method involves simulations where physical quarks are paired\nwith auxiliary quarks in unphysical \"isospin\" doublets and a decoupling of the\nauxiliary quarks by mass reweighting."
    },
    {
        "anchor": "Study of the pseudoscalar glueball in $J/\u03c8$ radiative decays: We aim to explore the production rate of the pseudoscalar glueball in\n$J/\\psi$ radiative decay by lattice QCD in quenched approximation. The\ncalculation is performed on three anisotropic lattices with the spatial lattice\nspacing ranging from 0.222(2) fm to 0.110(1) fm. As a calibration of some\nsystematical uncertainties, we first extract the $M1$ form factor $\\hat{V}(0)$\nof the process $J/\\psi\\to\\gamma\\eta_{c}$ and get the result\n$\\hat{V}(0)=1.933(41)$ in the continuum limit, which gives the partial width\n$\\Gamma(J/\\psi\\to\\gamma\\eta_{c})=2.47(11)$ keV. These results are in agreement\nwith that of previous lattice studies. As for the pseudoscalar glueball\n$G_{0^{-+}}$, its mass is derived to be $2.395(14)$ GeV, and the form factor\n$\\hat{V}(0)$ of the process $J/\\psi\\to\\gamma G_{0^{-+}}$ is determined to be\n$\\hat{V}(0)=0.0246(43)$ after continuum extrapolation. Finally, the production\nrate of the pseudoscalar glueball is predicted to be $2.31(90)\\times10^{-4}$,\nwhich is much smaller than that of conventional light $q\\bar{q}$ $\\eta$ states.\nAfter the subtraction of the phase space factor, the couplings of $J/\\psi\nX\\gamma$ are similar where $X$ stands for $\\eta$ states and the pseudoscalar\nglueball. Possibly, the $U_{A}(1)$ anomaly plays an important role for the\nlarge couplings of gluons to the flavor singlet $\\eta$ states in $J/\\psi$\nradiative decays.",
        "positive": "Lattice Calculation of Nucleon Isovector Axial Charge with Improved\n  Currents: We employ dimension-4 operators to improve the local vector and axial-vector\ncurrents and calculate the nucleon isovector axial coupling $g^3_A$ with\noverlap valence on $2+1$-flavor Domain Wall Fermion sea. Using the equality of\n$g^3_A$ from the spatial and temporal components of the axial-vector current as\na normalization condition, we find that $g_A^3$ is increased by a few percent\ntowards the experimental value. The excited-state contamination has been taken\ninto account with three time separations between the source and sink. The\nimproved axial charges $g_A^{3}(24I)=1.22(4)$ and $g_A^{3}(32I)=1.21(3)$ are\nobtained on a $24^3\\times 64$ lattice at pion mass of 330 MeV and a $32^3\\times\n64$ lattice at pion mass 300 MeV are increased by $3.4\\%$ and $1.7\\%$ from\ntheir unimproved values, respectively. We have also used clover fermion on the\nsame DWF configurations and find the same behavior for the local axial charge\nas that of the overlap fermion."
    },
    {
        "anchor": "Finite-density lattice QCD and sign problem: current status and open\n  problems: This an English translation of a review of finite-density lattice QCD. The\noriginal version in Japanese appeared in Soryushiron Kenkyu Vol 31 (2020) No.\n1.",
        "positive": "On the Measure of Simplicial Quantum Gravity in Four Dimensions: We study quantum gravity in the path-integral formulation using the Regge\ncalculus. In spite of the unbounded gravitational action the existence of an\nentropy-dominated phase is confirmed. The influence of various types of\nmeasures on this phase structure is investigated and our results are compared\nwith those obtained by dynamical triangulation."
    },
    {
        "anchor": "Lattice QCD Results at Finite Temperature and Density: Recent lattice results on QCD at finite temperatures and densities are\nreviewed. Two new and independent techniques give compatible results for\nphysical quantities. The phase line separating the hadronic and quark-gluon\nplasma phases, the critical endpoint and the equation of state are discussed.",
        "positive": "Multi-particle interpolating operators in quantum field theories with\n  cubic symmetry: Numerical studies of lattice quantum field theories are conducted in finite\nspatial volumes, typically with cubic symmetry in the spatial coordinates.\nMotivated by these studies, this work presents a general algorithm to construct\nmulti-particle interpolating operators for quantum field theories with cubic\nsymmetry. The algorithm automates the block diagonalization required to combine\nmultiple operators of definite linear momentum into irreducible representations\nof the appropriate little group. Examples are given for distinguishable and\nindistinguishable particles including cases with both zero and non-zero spin.\nAn implementation of the algorithm is publicly available at\nhttps://github.com/latticeqcdtools/mhi."
    },
    {
        "anchor": "Moving NRQCD for heavy-to-light form factors on the lattice: We formulate Non-Relativistic Quantum Chromodynamics (NRQCD) on a lattice\nwhich is boosted relative to the usual discretization frame. Moving NRQCD\n(mNRQCD) allows us to treat the momentum for the heavy quark arising from the\nframe choice exactly. We derive mNRQCD through O(1/m^2,v^4), as accurate as the\nNRQCD action in present use, both in the continuum and on the lattice with\nO(a^4) improvements. We have carried out extensive tests of the formalism\nthrough calculations of two-point correlators for both heavy-heavy\n(bottomonium) and heavy-light (B_s) mesons in 2+1 flavor lattice QCD and\nobtained nonperturbative determinations of energy shift and external momentum\nrenormalization. Comparison to perturbation theory at O(\\alpha_s) is also made.\nThe results demonstrate the effectiveness of mNRQCD. In particular we show that\nthe decay constants of heavy-light and heavy-heavy mesons can be calculated\nwith small systematic errors up to much larger momenta than with standard\nNRQCD.",
        "positive": "Thermodynamics of lattice QCD with 2 flavours of colour-sextet quarks: A\n  model of walking/conformal Technicolor: QCD with two flavours of massless colour-sextet quarks is considered as a\nmodel for conformal/walking Technicolor. If this theory possess an infrared\nfixed point, as indicated by 2-loop perturbation theory, it is a\nconformal(unparticle) field theory. If, on the other hand, a chiral condensate\nforms on the weak-coupling side of this would-be fixed point, the theory\nremains confining. The only difference between such a theory and regular QCD is\nthat there is a range of momentum scales over which the coupling constant runs\nvery slowly (walks). In this first analysis, we simulate the lattice version of\nQCD with two flavours of staggered quarks at finite temperatures on lattices of\ntemporal extent $N_t=4$ and 6. The deconfinement and chiral-symmetry\nrestoration couplings give us a measure of the scales associated with\nconfinement and chiral-symmetry breaking. We find that, in contrast to what is\nseen with fundamental quarks, these transition couplings are very different.\n$\\beta=6/g^2$ for each of these transitions increases significantly from\n$N_t=4$ and $N_t=6$ as expected for the finite temperature transitions of an\nasymptotically-free theory. This suggests a walking rather than a conformal\nbehaviour, in contrast to what is observed with Wilson quarks. In contrast to\nwhat is found for fundamental quarks, the deconfined phase exhibits states in\nwhich the Polyakov loop is oriented in the directions of all three cube roots\nof unity. At very weak coupling the states with complex Polyakov loops undergo\na transition to a state with a real, negative Polyakov loop."
    },
    {
        "anchor": "Constraining the QCD phase diagram at finite temperature and density: Neither the chiral limit nor finite baryon density can be simulated directly\nin lattice QCD, which severely limits our understanding of the QCD phase\ndiagram. In this review I collect results for the phase structure in an\nextended parameter space of QCD, with varying numbers of flavours, quark\nmasses, colours, lattice spacings, imaginary and isospin chemical potentials.\nSuch studies help in understanding the underlying symmetries and degrees of\nfreedom, and are beginning to provide a consistent picture constraining the\npossibilities for the physical phase diagram.",
        "positive": "Unphysical phases in staggered chiral perturbation theory: We study the phase diagram for staggered quarks using chiral perturbation\ntheory. In beyond-the-standard-model simulations using a large number ($>8$) of\nstaggered fermions, unphysical phases appear for coarse enough lattice spacing.\nWe argue chiral perturbation theory can be used to interpret one of these\nphases. In addition, we show only three broken phases for staggered quarks\nexist, at least for lattice spacings in the regime $a^2\\ll \\Lambda^2_{\\rm\nQCD}$."
    },
    {
        "anchor": "Renormalisation of the scalar energy-momentum tensor with the Wilson\n  flow: The non-perturbative computation of the energy-momentum tensor can be used to\nstudy the scaling behaviour of strongly coupled quantum field theories. The\nWilson flow is an essential tool to find a meaningful formulation of the\nenergy-momentum tensor on the lattice. We extend recent studies of the\nrenormalisation of the energy-momentum tensor in four-dimensional gauge theory\nto the case of a three-dimensional scalar theory to investigate its intrinsic\nstructure and numerical feasibility on a more basic level. In this paper, we\ndiscuss translation Ward identities, introduce the Wilson flow for scalar\ntheory, and present our results for the renormalisation constants of the scalar\nenergy-momentum tensor.",
        "positive": "Dynamical supersymmetry breaking and phase diagram of the lattice\n  Wess-Zumino model: We study dynamical supersymmetry breaking and the transition point by\nnon-perturbative lattice techniques in a class of two-dimensional N=1\nWess-Zumino model. The method is based on the calculation of rigorous lower\nbounds on the ground state energy density in the infinite-lattice limit. Such\nbounds are useful in the discussion of supersymmetry phase transition. The\ntransition point is determined with this method and then compared with recent\nresults based on large-scale Green Function Monte Carlo simulations with good\nagreement."
    },
    {
        "anchor": "Banks-Casher-type relations for complex Dirac spectra: For theories with a sign problem there is no analog of the Banks-Casher\nrelation. This is true in particular for QCD at nonzero quark chemical\npotential. However, for QCD-like theories without a sign problem the\nBanks-Casher relation can be extended to the case of complex Dirac eigenvalues.\nWe derive such extensions for the zero-temperature, high-density limits of\ntwo-color QCD, QCD at nonzero isospin chemical potential, and adjoint QCD. In\nall three cases the density of the complex Dirac eigenvalues at the origin is\nproportional to the BCS gap squared.",
        "positive": "The strangeness content of the nucleon: We evaluate the matrix element of $\\bar{q} q$ in hadron states on a lattice.\nWe find substantial mixing of the connected and disconnected contributions so\nthat the lattice result that the disconnected contribution to the nucleon is\nlarge does not imply that the $\\bar{s} s$ content is large. This has\nimplications for dark matter searches."
    },
    {
        "anchor": "Failure of Universality in Noncompact Lattice Field Theories: The nonuniversal behavior of two noncompact nonlinear sigma models is\ndescribed. When these theories are defined on a lattice, the behavior of the\norder parameter (magnetization) near the critical point is sensitive to the\ndetails of the lattice definition. This is counter to experience and to\nexpectations based on the ideas of universality.",
        "positive": "Renormalization of the effective theory for heavy quarks at small\n  velocity: The slope of the Isgur-Wise function at the normalization point,\n$\\xi^{(1)}(1)$,is one of the basic parameters for the extraction of the $CKM$\nmatrix element $V_{cb}$ from exclusive semileptonic decay data. A method for\nmeasuring this parameter on the lattice is the effective theory for heavy\nquarks at small velocity $v$. This theory is a variant of the heavy quark\neffective theory in which the motion of the quark is treated as a perturbation.\nIn this work we study the lattice renormalization of the slow heavy quark\neffective theory. We show that the renormalization of $\\xi^{(1)}(1)$ is not\naffected by ultraviolet power divergences, implying no need of difficult\nnon-perturbative subtractions. A lattice computation of $\\xi^{(1)}(1)$ with\nthis method is therefore feasible in principle. The one-loop renormalization\nconstants of the effective theory for slow heavy quarks are computed to order\n$v^2$ together with the lattice-continuum renormalization constant of\n$\\xi^{(1)}(1)$ . We demonstrate that the expansion in the heavy-quark velocity\nreproduces correctly the infrared structure of the original (non-expanded)\ntheory to every order. We compute also the one-loop renormalization constants\nof the slow heavy quark effective theory to higher orders in $v^2$ and the\nlattice-continuum renormalization constants of the higher derivatives of the\n$\\xi$ function. Unfortunately, the renormalization constants of the higher\nderivatives are affected by ultraviolet power divergences, implying the\nnecessity of numerical non-perturbative subtractions. The lattice computation\nof higher derivatives of the Isgur-Wise function seems therefore problematic."
    },
    {
        "anchor": "Gauge theories with fermions in two-index representations: After some introductory comments on the peculiar features of slowly running\ntheories, I will report results obtained using the Schrodinger functional\ntechnique for two gauge theories that are believed to lie near the bottom of\nthe conformal window: the SU(3) theory with two adjoint Dirac fermions, and the\nSU(4) theory with six Dirac fermions in the two-index antisymmetric\nrepresentation. In both cases we find a small beta function in strong coupling,\nbut we cannot confirm or rule out an infrared fixed point. In both theories the\nmass anomalous dimension levels off, staying well below 0.5, much like the\ntheories with fermions in the two-index symmetric representation investigated\nearlier.",
        "positive": "Light hadron spectroscopy and pseudoscalar decay constants: I review recent lattice QCD results on light hadron spectroscopy and\npseudoscalar decay constants."
    },
    {
        "anchor": "Lattice QCD calculation of form factors for $\u039b_b \\to \u039b(1520)\n  \\ell^+ \\ell^-$ decays: Experimental results for mesonic $b \\to s \\mu^+ \\mu^-$ decays show a pattern\nof deviations from Standard-Model predictions, which could be due to new\nfundamental physics or due to an insufficient understanding of hadronic\neffects. Additional information on the $b \\to s \\mu^+ \\mu^-$ transition can be\nobtained from $\\Lambda_b$ decays. This was recently done using the process\n$\\Lambda_b \\to \\Lambda \\mu^+ \\mu^-$, where the $\\Lambda$ is the lightest\nstrange baryon. A further interesting channel is $\\Lambda_b \\to p^+ K^- \\mu^+\n\\mu^-$, where the $p^+ K^-$ final state receives contributions from multiple\nhigher-mass $\\Lambda$ resonances. The narrowest and most prominent of these is\nthe $\\Lambda(1520)$, which has $J^P=\\frac32^-$. Here we present an ongoing\nlattice QCD calculation of the relevant $\\Lambda_b \\to \\Lambda(1520)$ form\nfactors. We discuss the choice of interpolating field for the $\\Lambda(1520)$,\nand explain our method for extracting the fourteen $\\Lambda_b \\to\n\\Lambda(1520)$ helicity form factors from correlation functions that are\ncomputed in the $\\Lambda(1520)$ rest frame. We present preliminary numerical\nresults at a pion mass of 340 MeV and a lattice spacing of 0.11 fm. This\ncalculation uses a domain-wall action for the $u$, $d$, and $s$ quarks and a\nrelativistic heavy-quark action for the $b$ quark, and is based on gauge-field\nconfigurations generated by the RBC and UKQCD Collaborations.",
        "positive": "Infinite volume, three-body scattering formalisms in the presence of\n  bound states: Strong interactions produce a rich spectrum of resonances that decay into\nthree or more hadrons. Understanding their phenomenology requires a theoretical\nframework to extract parameters fromexperimental data and Lattice QCD\nsimulations of hadron scattering. Two classes of relativistic three-body\napproaches are currently being pursued: the EFT-based and unitarity-based one.\nWe consider a model of relativistic three-body scattering with an S-wave bound\nstate in the two-body sub-channel using both formalisms. We present and discuss\nnumerical solutions for the multi-hadron scattering amplitudes in different\nkinematical regions, obtained from integral equationsof the EFT-based approach.\nThe connection of our work to the ongoing program of computingthe three-body\nspectrum from the lattice is highlighted. Finally, we show how to generalizethe\nunitarity-based framework to include all relevant open channels, discuss the\nnonphysicalsingularities near the physical region, and show how to eliminate\nthem in a simple case."
    },
    {
        "anchor": "Two-flavor lattice QCD simulation in the epsilon-regime with exact\n  chiral symmetry: We perform lattice simulations of two-flavor QCD using Neuberger's overlap\nfermion, with which the exact chiral symmetry is realized at finite lattice\nspacings. The epsilon-regime is reached by decreasing the light quark mass down\nto 3 MeV on a 16^3 32 lattice with a lattice spacing \\sim 0.11 fm. We find a\ngood agreement of the low-lying Dirac eigenvalue spectrum with the analytical\npredictions of the chiral random matrix theory, which reduces to the chiral\nperturbation theory in the epsilon-regime. The chiral condensate is extracted\nas \\Sigma(2 GeV) = (251(7)(11) MeV)^3, where the errors are statistical and an\nestimate of the higher order effects in the epsilon-expansion.",
        "positive": "Dimensional transmutation in the longitudinal sector of equivariantly\n  gauge-fixed Yang-Mills theory: We study the pure-gauge sector of an $SU(N)$ gauge theory, equivariantly\ngauge fixed to $SU(N-1)\\times U(1)$, which is an asymptotically free non-linear\nsigma model in four dimensions. We show that dimensional transmutation takes\nplace in the large-$N$ limit, and elaborate on the relevance of this result for\na speculative scenario in which the strong longitudinal dynamics gives rise to\na novel Higgs-Coulomb phase."
    },
    {
        "anchor": "Hamiltonian Monte Carlo simulation of the two-dimensional Wess-Zumino\n  model: We study a Hamiltonian lattice version of the two-dimensional Wess-Zumino\nmodel. Preliminary results obtained by Quantum Monte Carlo with a\nmany-parameter guiding wave function are presented. We analyze the pattern of\nsupersymmetry breaking by measuring the ground state energy and a set of\nsupersymmetric Ward identities. The algorithm is quite effective and allows\nvery precise measurements.",
        "positive": "Lattice calculation of the pion mass difference\n  $M_{\u03c0^{+}}-M_{\u03c0^{0}}$ at order $\\mathcal{O}(\u03b1_{em})$: We present a lattice calculation of the charged/neutral pion mass difference\n$M_{\\pi^{+}}-M_{\\pi^{0}}$ at order $\\mathcal{O}(\\alpha_{em})$ using the gauge\nconfigurations produced by the Extended Twisted Mass Collaboration with\n$N_{f}=2+1+1$ dynamical quark flavours at three values of the lattice spacing\n($a \\simeq 0.062, 0.082, 0.089~{\\rm fm}$) and pion masses in the range $M_{\\pi}\n\\simeq 250-500~{\\rm MeV}$. We employ the RM123 method and expand the\npath-integral around the isospin symmetric point at leading order in the\nelectromagnetic coupling $\\alpha_{em}$. Making use of the recently proposed RTM\nscheme, we evaluate the full $\\mathcal{O}(\\alpha_{em})$ contribution, with the\ninclusion of the disconnected diagram. At the physical point, after performing\nthe continuum and infinite volume extrapolation, we obtain the value\n$M_{\\pi^{+}}-M_{\\pi^{0}}= 4.622~(95)~{\\rm MeV}$ which is in good agreement with\nthe experimental result $[ M_{\\pi^{+}} - M_{\\pi^{0}} ]^{exp.} = 4.5936(5)~{\\rm\nMeV}$."
    },
    {
        "anchor": "Lattice Gauge Fields and Noncommutative Geometry: Conventional approaches to lattice gauge theories do not properly consider\nthe topology of spacetime or of its fields. In this paper, we develop a\nformulation which tries to remedy this defect. It starts from a cubical\ndecomposition of the supporting manifold (compactified spacetime or spatial\nslice) interpreting it as a finite topological approximation in the sense of\nSorkin. This finite space is entirely described by the algebra of cochains with\nthe cup product. The methods of Connes and Lott are then used to develop gauge\ntheories on this algebra and to derive Wilson's actions for the gauge and Dirac\nfields therefrom which can now be given geometrical meaning. We also describe\nvery natural candidates for the QCD theta term and Chern-Simons action\nsuggested by this algebraic formulation. Some of these formulations are simpler\nthan currently available alternatives. The paper treats both the functional\nintegral and Hamiltonian approaches.",
        "positive": "Vacuum type of SU(2) gluodynamics in maximally Abelian and Landau gauges: The vacuum type of SU(2) gluodynamics is studied using Monte-Carlo\nsimulations in maximally Abelian (MA) gauge and in Landau (LA) gauge, where the\ndual Meissner effect is observed to work. The dual Meissner effect is\ncharacterized by the coherence and the penetration lengths. Correlations\nbetween Wilson loops and electric fields are evaluated in order to measure the\npenetration length in both gauges. The coherence length is shown to be fixed in\nthe MA gauge from measurements of the monopole density around the static\nquark-antiquark pair. It is also shown numerically that a dimension 2 gluon\noperator A^+A^-(s) and the monopole density has a strong correlation as\nsuggested theoretically. Such a correlation is observed also between the\nmonopole density and A^2(s)= A^+A^-(s) + A^3A^3(s) condensate if the remaining\nU(1) gauge degree of freedom is fixed to U(1) Landau gauge (U1LA). The\ncoherence length is determined numerically also from correlations between\nWilson loops and A^+A^-(s) and A^2(s) in MA + U1LA gauge. Assuming that the\nsame physics works in the LA gauge, we determine the coherence length from\ncorrelations between Wilson loops and A^2(s). Penetration lengths and coherence\nlengths in the two gauges are almost the same. The vacuum type of the\nconfinement phase in both gauges is near to the border between the type 1 and\nthe type 2 dual superconductors."
    },
    {
        "anchor": "Confinement from Gauge Invariance in 2+1 Dimensions: It is shown, in D=2+1 dimensions, that by merely imposing non-abelian gauge\ninvariance on the temporal gauge ground state wavefunctional of an abelian\ngauge theory, a confining state is obtained.",
        "positive": "Towards an Abelian Formulation of Lattice QCD Confinement: We probe for operators occurring in the APQCD(``abelian-projected QCD'')\naction by evaluating abelian-projected $1$-plaquette spectral densities in pure\ngauge $SU(3)$ fixed to maximal abelian gauge. Couplings $B_{APQCD}(q,L)$ are\nextracted from the spectral densities for each representation $q$, $L\\times L$\nplaquette. While APQCD is dominated by a $q=L=1$ resonance, we also find\nevidence for weakly coupled $L=2$ plaquettes. Moreover, since $B_{APQCD}(1,1) >\nB_{QED}(1,1)$ even if $\\beta_{QED} > \\beta_c$, $L>1$ plaquettes must be\nsignificant since APQCD is confining."
    },
    {
        "anchor": "Nonperturbative infrared finiteness in super-renormalisable scalar\n  quantum field theory: We present a study of the IR behaviour of a three-dimensional\nsuper-renormalisable quantum field theory (QFT) consisting of a scalar field in\nthe adjoint of $SU(N)$ with a $\\varphi^4$ interaction. A bare mass is required\nfor the theory to be massless at the quantum level. In perturbation theory the\ncritical mass is ambiguous due to infrared (IR) divergences and we indeed find\nthat at two-loops in lattice perturbation theory the critical mass diverges\nlogarithmically. It was conjectured long ago in [Jackiw 1980, Appelquist 1981]\nthat super-renormalisable theories are nonperturbatively IR finite, with the\ncoupling constant playing the role of an IR regulator. Using a combination of\nMarkov-Chain-Monte-Carlo simulations of the lattice-regularised theory, both\nfrequentist and Bayesian data analysis, and considerations of a corresponding\neffective theory we gather evidence that this is indeed the case.",
        "positive": "Equation of state in 2+1 flavor QCD with improved Wilson quarks by the\n  fixed scale approach: We study the equation of state in 2+1 flavor QCD with nonperturbatively\nimproved Wilson quarks coupled with the RG-improved Iwasaki glue. We apply the\n$T$-integration method to nonperturbatively calculate the equation of state by\nthe fixed-scale approach. With the fixed-scale approach, we can purely vary the\ntemperature on a line of constant physics without changing the system size and\nrenormalization constants. Unlike the conventional fixed-$N_t$ approach, it is\neasy to keep scaling violations small at low temperature in the fixed scale\napproach. We study 2+1 flavor QCD at light quark mass corresponding to\n$m_\\pi/m_\\rho \\simeq 0.63$, while the strange quark mass is chosen around the\nphysical point. Although the light quark masses are heavier than the physical\nvalues yet, our equation of state is roughly consistent with recent results\nwith highly improved staggered quarks at large $N_t$."
    },
    {
        "anchor": "The Delta-resonance in a finite volume: We study the extraction of Delta-resonance parameters from lattice data for\nsmall quark masses, corresponding to the case of an unstable Delta. To this\nend, we calculate the spectrum of the correlator of two Delta-fields in a\nfinite Euclidian box up-to-and-including O(epsilon^3) in the small scale\nexpansion using infrared regularization. On the basis of our numerical study,\nwe argue that the extraction of the parameters of the Delta-resonance (in\nparticular, of the mass and the pion-nucleon-delta coupling constant) from the\nmeasured volume dependence of the lowest energy levels should be feasible.",
        "positive": "B-physics with $N_f=2$ Wilson fermions: We report the final results of the ALPHA collaboration for some B-physics\nobservables: $f_B$, $f_{B_s}$ and $m_b$. We employ CLS configurations with 2\nflavors of $O(a)$ improved Wilson fermions in the sea and pion masses ranging\ndown to 190 MeV. The b-quark is treated in HQET to order $1/m_b$. The\nrenormalization, the matching and the improvement were performed\nnon-perturbatively, and three lattice spacings reaching $a=0.048$ fm are used\nin the continuum extrapolation."
    },
    {
        "anchor": "Physics of the Electroweak Phase Transition at M_H <= 70 GeV in a\n  3-dimensional SU(2)-Higgs Model: Physical parameters of the electroweak phase transition in a 3d effective\nlattice SU(2)-Higgs model are presented. The phase transition temperatures,\nlatent heats and continuum condensate discontinuities are measured at Higgs\nmasses of about 70 and 35 GeV. Masses and Higgs condensates are compared to\nperturbation theory in the broken phase. In the symmetric phase bound states\nand the static force are determined.",
        "positive": "A novel computation of the thermodynamics of the SU(3) Yang-Mills theory: We present an accurate computation of the Equation of State of the SU(3)\nYang-Mills theory using shifted boundary conditions in the temporal direction.\nIn this framework, the entropy density s can be obtained in a simple way from\nthe expectation value of the space-time components T0k of the energy-momentum\ntensor. At each given value of the temperature, s is measured in an independent\nway at several values of the lattice spacing. The extrapolation to the\ncontinuum limit shows small discretization effects with respect to the\nstatistical errors of approximatively 0.5%."
    },
    {
        "anchor": "Study of Cluster Fluctuations in Two-dimensional q-State Potts Model: The two-dimensional Potts Model with 2 to 10 states is studied using a\ncluster algorithm to calculate fluctuations in cluster size as well as commonly\nused quantities like equilibrium averages and the histograms for energy and the\norder parameter. Results provide information about the variation of cluster\nsizes depending on the temperature and the number of states. They also give\nevidence for first-order transition when energy and the order parameter related\nmeasurables are inconclusive on small size lattices.",
        "positive": "Simple Matrix Elements with Dynamical Fermions: We report on studies of simple matrix elements from simulations with two\nflavors of sea quarks, both staggered and Wilson. We show the decay constants\nof vector and pseudoscalar mesons. The effects of sea quarks are small. These\nsimulations are done at relatively large lattice spacing compared to most\nquenched studies."
    },
    {
        "anchor": "A Stochastic Method for Computing Hadronic Matrix Elements: We present a stochastic method for the calculation of baryon three-point\nfunctions that is more versatile compared to the typically used sequential\nmethod. We analyze the scaling of the error of the stochastically evaluated\nthree-point function with the lattice volume and find a favorable\nsignal-to-noise ratio suggesting that our stochastic method can be used\nefficiently at large volumes to compute hadronic matrix elements.",
        "positive": "Surface Tension, Surface Stiffness, and Surface Width of the\n  3-dimensional Ising Model on a Cubic Lattice: We compute properties of the interface of the 3-dimensional Ising model for a\nwide range of temperatures and for interface extensions up to 64 by 64. The\ninterface tension sigma is obtained by integrating the surface energy density\nover the inverse temperature beta. The surface stiffness coefficient kappa is\ndetermined. We also study universal quantities like xi^2 sigma and xi^2 kappa.\nThe behavior of the interfacial width on lattices up to 512 times 512 times 27\nis also investigated."
    },
    {
        "anchor": "The meson spectrum of large N gauge theories: We present our preliminary results on the determination of the low lying\nmeson spectrum for pure gauge theory in the large $N$ limit. Some results are\nalso shown for the theory with two flavours of quarks in the adjoint\nrepresentation.",
        "positive": "Combinatorics of Lattice QCD at Strong Coupling: Thermodynamics in the strong coupling limit of lattice QCD has features which\nmay be similar to those of continuum QCD, such as a chiral critical end point\nand a nuclear liquid gas transition. Here I compare the combinatorics of\nstaggered and Wilson fermions in the strong coupling limit for arbitrary number\nof colors and flavors. The partition functions can be considered as an\nexpansions in hadronic spatial hoppings from the static limit, where both\ndiscretizations can be expressed via formulae with coefficients of distinct\ncombinatorial interpretation. The corresponding multiplicites of hadronic\nstates are evaluated using generalizations of Catalan numbers and Lucas\npolynomials. I outline how quantum Monte Carlo simulations can be carried out\nin general, and summarize recent results on the gauge corrections to the strong\ncoupling limit."
    },
    {
        "anchor": "The Scalar Quarkonium Spectrum and Quarkonium-Glueball Mixing: We evaluate the valence approximation to the mass of scalar quarkonium and to\nthe mixing energy between scalar quarkonium and the lightest scalar glueball\nfor a range of different lattice sizes and quark masses. Our results support\nthe identification of $f_0(1710)$ as the lightest scalar glueball.",
        "positive": "Image-processing the topological charge density in the CP(N-1) model: We study the topological charge density distribution using the\ntwo-dimensional $CP^{N-1}$ model. We numerically compute not only the\ntopological susceptibility, which is a spatially global quantity to probe\ntopological properties of the whole system, but also the topological charge\ncorrelator with finite momentum. We perform Fourier power spectrum analysis for\nthe topological charge density for various values of the inverse temperature\n$\\beta$. We propose to utilize the Fourier entropy as a convenient measure to\ncharacterize spatial distribution patterns and demonstrate that the Fourier\nentropy exhibits nontrivial temperature dependence. We also consider the\nsnapshot entropy defined with the singular value decomposition, which also\nturns out to behave nonmonotonically with the temperature. We give a possible\ninterpretation suggested from the strong-coupling analysis."
    },
    {
        "anchor": "The path optimization for the sign problem of low dimensional QCD: The path optimization has been proposed to weaken the sign problem which\nappears in some field theories such as finite density QCD. In this method, we\noptimize the integration path in complex plain to enhance the average phase\nfactor. In this study, we discuss the application of this method to low\ndimensional QCD as a first step of finite density QCD.",
        "positive": "Numerical studies of Minimally Doubled Fermions: We have performed the first numerical study of minimally doubled fermions of\nthe Karsten-Wilczek class in the quenched approximation. This requires fixing\nthe counterterms, which arise due to hypercubic symmetry breaking induced by\nthe Karsten-Wilczek term. Non-perturbative renormalisation criteria are\nformulated after a detailed study of the parameter dependence of mesonic\nobservables. Minimisation of the mass anisotropy of the pseudoscalar ground\nstate fixes non-perturbative renormalisation conditions for the counterterm\ncoefficients. These anisotropies are mapped out by probing different euclidean\ncomponents of the transfer matrix through calculations of the pseudoscalar\nground state mass in different directions. The chiral behaviour of the\npseudoscalar ground state is studied with the tuned Karsten-Wilczek action for\nmultiple lattice spacings. Light pseudoscalar masses ($ M_{PS} \\lesssim\n250\\,MeV $) were achieved in the quenched approximation without encountering\nexceptional configurations. The presence of quenched chiral logarithms is\nstudied under the tentative assumption of Goldstone Boson-like behaviour."
    },
    {
        "anchor": "Determination of $B_K$ using improved staggered fermions (II) SU(2)\n  chiral perturbation theory fit: We present results for $B_K$ calculated using HYP-smeared improved staggered\nfermions on the MILC asqtad lattices. In this report, the data is analyzed\nusing the results of SU(2) staggered chiral perturbation theory (SChPT). We\noutline the derivation of the NLO SU(2) SChPT result, explain our fitting\nprocedure, and outline how we estimate systematic errors. We also show the\nlight sea-quark mass and lattice spacing dependence for both SU(2) and\nSU(3)-based analyses. Our preliminary result from the SU(2) analysis is\n$B_K(\\text{NDR}, \\mu = 2 \\text{GeV}) = 0.512 \\pm 0.014 \\pm 0.034$ and\n$\\hat{B}_K = B_K(\\text{RGI})= 0.701 \\pm 0.019 \\pm 0.047$. This is somewhat more\naccurate than our result from the SU(3) analysis. It is consistent with results\nobtained using valence domain-wall fermions",
        "positive": "Self-avoiding random surfaces with fluctuating topology: A gas of self-avoiding surfaces with an arbitrary polynomial coupling to the\ngaussian curvature and an extrinsic curvature term can be realized in a\nthree-dimensional Ising bcc lattice with only three local couplings. Similar\nthree parameter realizations are valid also in other lattices. The relation\nbetween the crumpling transition and the roughening is discussed. It turns out\nthat the mean area of these surfaces is proportional to its genus."
    },
    {
        "anchor": "Mesonic Wavefunctions in the three-dimensional Gross-Neveu model: We present results from a numerical study of bound state wavefunctions in the\n(2+1)-dimensional Gross-Neveu model with staggered lattice fermions at both\nzero and nonzero temperature. Mesonic channels with varying quantum numbers are\nidentified and analysed. In the strongly coupled chirally broken phase at T=0\nthe wavefunctions expose effects due to varying the interaction strength more\neffectively than straightforward spectroscopy. In the weakly coupled chirally\nrestored phase information on fermion - antifermion scattering is recovered. In\nthe hot chirally restored phase we find evidence for a screened interaction.\nThe T=0 chirally symmetric phase is most readily distinguished from the\nsymmetric phase at high T via the fermion dispersion relation.",
        "positive": "Opening the Rome-Southampton window for operator mixing matrices: We show that the running of operators which mix under renormalization can be\ncomputed fully non-perturbatively as a product of continuum step scaling\nmatrices. These step scaling matrices are obtained by taking the \"ratio\" of Z\nmatrices computed at different energies in an RI-MOM type scheme for which\ntwisted boundary conditions are an essential ingredient. Our method allows us\nto relax the bounds of the Rome-Southampton window. We also explain why such a\nmethod is important in view of the light quark physics program of the RBC-UKQCD\ncollaborations. To illustrate our method, using n_f=2+1 domain-wall fermions,\nwe compute the non-perturbative running matrix of four-quark operators needed\nin K->pipi decay and neutral kaon mixing. Our results are then compared to\nperturbation theory."
    },
    {
        "anchor": "Critical Point Correlation Function for the 2D Random Bond Ising Model: High accuracy Monte Carlo simulation results for 1024*1024 Ising system with\nferromagnetic impurity bonds are presented. Spin-spin correlation function at a\ncritical point is found to be numerically very close to that of a pure system.\nThis is not trivial since a critical temperature for the system with impurities\nis almost two times lower than pure Ising $T_c$. Finite corrections to the\ncorrelation function due to combined action of impurities and finite lattice\nsize are described.",
        "positive": "Numerical simulation of high quark densities in QCD with two colours: The DESY-Swansea Collaboration performed numerical simulations investigating\nSU(2) lattice gauge theory at non-zero chemical potential with one staggered\nquark flavour in the adjoint representation. This lattice model has similar\nfeatures to QCD itself and its study gives interesting insights into some open\nproblems of high density quark matter. In particular the role of the ``sign\nproblem'' can be clarified in connection with diquark condensation and the\nphase diagram."
    },
    {
        "anchor": "Two-dimensional Lattice Gross-Neveu Model with Wilson Fermion Action at\n  Finite Temperature and Chemical Potential: We investigate the phase structure of the two-dimensional lattice Gross-Neveu\nmodel formulated with the Wilson fermion action to leading order of 1/N\nexpansion. Structural change of the parity-broken phase under the influence of\nfinite temperature and chemical potential is studied. The connection between\nthe lattice phase structure and the chiral phase transition of the continuum\ntheory is clarified.",
        "positive": "1+1+1 flavor QCD + QED simulation at the physical point: We present the results of 1+1+1 flavor QCD+QED simulation at the physical\npoint, in which the dynamical quark effects in QED and the up-down quark mass\ndifference are incorporated by the reweighting technique. The physical quark\nmasses together with the lattice spacing are determined with $m_{\\pi^+}$,\n$m_{K^+}$, $m_{K^0}$ and $m_{\\Omega^-}$ as physical inputs. Calculations are\ncarried out using a set of 2+1 flavor QCD configurations near the physical\npoint generated by the non-perturbatively $O(a)$-improved Wilson quark action\nand the Iwasaki gauge action at $\\beta=1.9$ on a $32^3\\times 64$ lattice. We\nevaluate the values of the up, down and strange quark masses individually with\nnon-perturbative QCD renormalization."
    },
    {
        "anchor": "The phase structure of the 3-d Thirring model: We study the phase structure of the Thirring model in 3-d and find it to be\ncompatible with the existence of a non gaussian fixed point of RG. A Finite\nSize Scaling argument is included in the equation of state in order to avoid\nthe assumptions usually needed to extrapolate to the thermodynamical limit.",
        "positive": "Maximizing the Bang Per Bit: Reducing memory traffic is critical to accelerate Lattice QCD computations on\nmodern processors, given that such computations are memory-bandwidth bound. A\ncommonly used strategy is mixed-precision solvers, however, these require\ncareful treatment to ensure stable convergence. We give an overview of the\nstrategies employed in QUDA to stabilize mixed-precision variants of Conjugate\nGradient (CG), and its multi-shift brethren. Through the use of customized\nnumerical storage formats we can significantly improve upon the precision\nachievable compared to IEEE numerical formats, increasing both the solver\nprecision and stability achievable at fixed word size. We give examples using\nBiCGStab(l) and multi-shift CG solvers using the HISQ operator."
    },
    {
        "anchor": "Structure-dependent electromagnetic finite-volume effects through order\n  $1/L^3$: We consider electromagnetic finite-volume effects through order $1/L^3$ in\ndifferent formulations of QED, where $L$ is the periodicity of the spatial\nvolume. An inherent problem at this order is the appearance of\nstructure-dependent quantities related to form factors and the analytical\nstructure of the correlation functions. The non-local constraint of the widely\nused QED$_{\\textrm{L}}$ regularization gives rise to structure-dependent\neffects that are difficult to evaluate analytically and can act as a precision\nbottleneck in lattice calculations. For this reason, we consider general volume\nexpansions relevant for the mass spectrum as well as leptonic decay rates in\nQED$_{\\textrm{C}}$, QED$_{\\textrm{L}}$ and QED$_{\\textrm{L}}^{\\textrm{IR}}$,\nthe latter being a class of non-local formulations generalising\nQED$_{\\textrm{L}}$. One choice within this class is QED$_{\\textrm{r}}$, first\nintroduced at this conference, and we show that the effects of non-locality for\nthe $1/L^3$ term in the expansion can be removed. We observe that there are\nstill $1/L^3$ contributions unrelated to the (non-)locality of the studied QED\nformulations, but rather to collinear singularities in the physical amplitudes.",
        "positive": "Low energy constants from the MILC Collaboration: Based on ongoing simulations, we update our results for low energy constants,\ndecay constants, and light quark masses. The simulations employ three dynamical\nflavors of improved staggered quarks."
    },
    {
        "anchor": "Quenched Chiral Perturbation Theory for Baryons: We develop chiral perturbation theory for baryons in quenched QCD. Quenching\n(the elimination of diagrams containing virtual quark loops) is achieved by\nextending the Lagrangian method of Bernard and Golterman, and is implemented in\na theory where baryons are treated as fixed velocity sources. Our method\nrequires that the octet baryons be represented by a three index tensor rather\nthan by the usual matrix field. We calculate the leading non-analytic\ncorrections to the masses of octet and decuplet baryons. In QCD these are\nproportional to $M_\\pi^3$. We find that quenching alters the $M_\\pi^3$ terms,\nbut does not completely remove them. In addition, we find non-analytic\ncontributions to baryon masses proportional to $M_\\pi$ and $M_\\pi^2 \\log\nM_\\pi$. These terms, which are artifacts of quenching, dominate over the\n$M_\\pi^3$ terms for sufficiently small quark masses. We also point out various\npecularities of the quenched theory, most notably that the $\\Delta$ baryon can\ndecay (if kinematically allowed), in the sense that its two point function will\nbe dominated at long Euclidean times by a nucleon plus pion intermediate state.",
        "positive": "General kinematics of the three-gluon vertex from quenched lattice QCD: We present new results for the transversely projected three-gluon vertex from\nquenched lattice QCD simulations using standard Wilson action. While previous\nworks focused in some particular kinematics such as the symmetric $(q^2 = r^2 =\np^2)$ and soft-gluon $(p = 0)$ cases, here we will present a detailed analysis\nof the bisectoral case $(r^2 = q^2 \\ne p^2)$ where the transversely projected\nvertex can be cast in terms of three independent tensors. The lattice data show\na clear dominance of the form-factor corresponding to the tree-level tensor,\nwhose dependence on the momenta can be almost entirely expressed in terms of\nthe symmetric combination of the momenta $s^2=(q^2+r^2+p^2)/2$."
    },
    {
        "anchor": "$K_{\\ell 3}$ form factors at the physical point: Toward the continuum\n  limit: We present updated results for the form factors of the kaon semileptonic\n$(K_{\\ell 3})$ decay process calculated with $N_f = 2 + 1$ nonperturbatively\n$O(a)$-improved Wilson quark action and Iwasaki gauge action at the physical\npoint on large volumes of more than (10 fm)$^4$. In addition to our previous\ncalculation at the lattice spacing $a = 0.085$ fm, we perform a calculation at\nthe second lattice spacing of $0.063$ fm. Using the results for the form\nfactors extracted from 3-point functions with the local and also conserved\nvector currents at the two lattice spacings, continuum extrapolation and\ninterpolation of the momentum transfer are carried out simultaneously to obtain\nthe value of the form factor $f_+(0)$ at the zero momentum transfer in the\ncontinuum limit. After investigation of stability of $f_+(0)$ against several\nfit forms and different data, we obtain $f_+(0) = 0.9615(10)(^{+47}_{\\\n-3})(5)$, where the first, second, and third errors are statistical, systematic\nerrors from choice of the fit forms and isospin breaking effect, respectively.\nCombining our value of $f_+(0)$ and experimental input of the $K_{\\ell 3}$\ndecay, one of the Cabibbo-Kobayashi-Maskawa matrix elements $|V_{us}|$ is\ndetermined as $|V_{us}| = 0.2252(^{\\ +5}_{-12})$, whose error contains the\nexperimental one as well as that in the lattice calculation. This value is\nreasonably consistent with the ones determined from recent lattice QCD results\nof $f_+(0)$ and also the one determined through the kaon leptonic decay\nprocess. We observe some tension between our value and $|V_{us}|$ evaluated\nfrom the unitarity of the CKM matrix with $|V_{ud}|$, while it depends on the\nsize of the error of $|V_{ud}|$. It is also found that $|V_{us}|$ determined\nwith our phase space integrals through six $K_{\\ell 3}$ decay processes is\nconsistent with the above one using $f_+(0)$.",
        "positive": "Staggered fermions simulations on GPUs: We present our implementation of the RHMC algorithm for staggered fermions on\nGraphics Processing Units using the NVIDIA CUDA programming language. While\nprevious studies exclusively deal with the Dirac matrix inversion problem, our\ncode performs the complete MD trajectory on the GPU. After pointing out the\nmain bottlenecks and how to circumvent them, we discuss the performance of our\ncode."
    },
    {
        "anchor": "The low-lying mass spectrum of the N=1 SU(2) SUSY Yang-Mills theory with\n  Wilson fermions: We analyze the low energy spectrum of bound states of the N=1 SU(2) SUSY\nYang-Mills Theory (SYM). This work continues the investigation of the\nnon-perturbative properties of SYM by Monte Carlo simulations in the Wilson\ndiscretization with dynamical gluinos. The dynamics of the gluinos is included\nby the Two-Step Multi-Bosonic Algorithm (TSMB) for dynamical fermions. A new\nset of configurations has been generated on a 16^3x32 lattice at beta=2.3 and\nkappa=0.194. The analysis also includes sets of configurations previously\ngenerated on a smaller (12^3x24) lattice at kappa=0.1925, 0.194 and 0.1955.\nGuided by predictions from low energy Lagrangians, we consider spin-1/2, scalar\nand pseudoscalar particles. The spectrum of SYM is a challenging subject of\ninvestigation because of the extremely noisy correlators. In particular,\nmeson-like correlators contain disconnected contributions. The larger\ntime-extention of the 16^3x32 lattice allows to observe two-state signals in\nthe effective mass. Finite-volume effects are monitored by comparing results\nfrom the two lattice sizes.",
        "positive": "The decay constants ${\\mathbf{f_D}}$ and ${\\mathbf{f_{D_{s}}}}$ in the\n  continuum limit of ${\\mathbf{N_f=2+1}}$ domain wall lattice QCD: We present results for the decay constants of the $D$ and $D_s$ mesons\ncomputed in lattice QCD with $N_f=2+1$ dynamical flavours. The simulations are\nbased on RBC/UKQCD's domain wall ensembles with both physical and unphysical\nlight-quark masses and lattice spacings in the range 0.11--0.07$\\,$fm. We\nemploy the domain wall discretisation for all valence quarks.\n  The results in the continuum limit are\n$f_D=208.7(2.8)_\\mathrm{stat}\\left(^{+2.1}_{-1.8}\\right)_\\mathrm{sys}\\,\\mathrm{MeV}$\nand\n$f_{D_{s}}=246.4(1.3)_\\mathrm{stat}\\left(^{+1.3}_{-1.9}\\right)_\\mathrm{sys}\\,\\mathrm{MeV}$\nand\n$f_{D_s}/f_D=1.1667(77)_\\mathrm{stat}\\left(^{+57}_{-43}\\right)_\\mathrm{sys}$.\nUsing these results in a Standard Model analysis we compute the predictions\n$|V_{cd}|=0.2185(50)_\\mathrm{exp}\\left(^{+35}_{-37}\\right)_\\mathrm{lat}$ and\n$|V_{cs}|=1.011(16)_\\mathrm{exp}\\left(^{+4}_{-9}\\right)_\\mathrm{lat}$ for the\nCKM matrix elements."
    },
    {
        "anchor": "Some Comments on Multigrid Methods for Computing Propagators: I make three conceptual points regarding multigrid methods for computing\npropagators in lattice gauge theory: 1) The class of operators handled by the\nalgorithm must be stable under coarsening. 2) Problems related by symmetry\nshould have solution methods related by symmetry. 3) It is crucial to\ndistinguish the vector space $V$ from its dual space $V^*$. All the existing\nalgorithms violate one or more of these principles.",
        "positive": "Justification of the complex Langevin method with the gauge cooling\n  procedure: Recently there has been remarkable progress in the complex Langevin method,\nwhich aims at solving the complex action problem by complexifying the dynamical\nvariables in the original path integral. In particular, a new technique called\nthe gauge cooling was introduced and the full QCD simulation at finite density\nhas been made possible in the high temperature (deconfined) phase or with heavy\nquarks. Here we provide a rigorous justification of the complex Langevin method\nincluding the gauge cooling procedure. We first show that the gauge cooling can\nbe formulated as an extra term in the complex Langevin equation involving a\ngauge transformation parameter, which is chosen appropriately as a function of\nthe configuration before cooling. The probability distribution of the\ncomplexified dynamical variables is modified by this extra term. However, this\nmodification is shown not to affect the Fokker-Planck equation for the\ncorresponding complex weight as far as observables are restricted to gauge\ninvariant ones. Thus we demonstrate explicitly that the gauge cooling can be\nused as a viable technique to satisfy the convergence conditions for the\ncomplex Langevin method. We also discuss the \"gauge cooling\" in 0-dimensional\nsystems such as vector models or matrix models."
    },
    {
        "anchor": "Effective Monopole Potential for SU(2) Lattice Gluodynamics in Spatial\n  Maximal Abelian Gauge: We investigate the dual superconductor hypothesis in finite-temperature SU(2)\nlattice gluodynamics in the Spatial Maximal Abelian gauge. This gauge is more\nphysical than the ordinary Maximal Abelian gauge due to absence of\nnon-localities in temporal direction. We show numerically that in the Spatial\nMaximal Abelian gauge the probability distribution of the abelian monopole\nfield is consistent with the dual superconductor mechanism of confinement: the\nabelian condensate vanishes in the deconfinement phase and is not zero in the\nconfinement phase.",
        "positive": "Disordered fermions, extra dimensions and a solvable Yang-Mills theory: Generalizing disorder couplings of the SYK model by means of SU(N) matrices\nwe formulate a lattice model of fermions in d+1 dimensions. Integration of\nfermions yields an effective theory of Yang-Mills fields in d dimensions, the\nlatter approaching the standard Yang-Mills theory in the case of heavy fermions\nand the classical limit of vanishing coupling constant of the theory. Quantum\nmechanically, the theory is solved using large N approximation of the dual\neffective theory of Hermitian matrices in d dimensions. The theory is\nasymptotically free and confines the color. In case of massless fermions the\nemerging theory is an asymptotic safe QCD theory. We discuss also the\nrelationship of this theory to the SYK model."
    },
    {
        "anchor": "Gluon PDF for the proton using the twisted mass formulation of lattice\n  QCD: We present results of the x-dependence of the unpolarized gluon PDF for the\nproton. We use an $N_f=2+1+1$ ensemble of maximally twisted mass fermions with\nclover improvement and the Iwasaki improved gluon action. The quark masses are\ntuned so that the pion mass is 260 MeV. We use a $32^3\\times64$ lattice size\nwith a lattice spacing $a=0.093$ fm giving a spatial extent of 3 fm. We employ\nthe pseudo-distribution approach and obtain the light-cone Ioffe time\ndistribution (ITD) combining data for nucleon momentum boosts up to 1.67 GeV\nand Wilson line lengths, $z$, up to 0.56 fm. We explore systematic effects such\nas the dependence on the maximum value of $z$ entering the fits to obtain the\ngluon PDF.",
        "positive": "Distribution of the color fields around static quarks: Flux tube\n  profiles: We report detailed calculations of the profiles of energy and action\ndensities in the quark-antiquark string in SU(2) lattice gauge theory."
    },
    {
        "anchor": "Precision tests of the J/psi from full lattice QCD: mass, leptonic width\n  and radiative decay rate to eta_c: We show results from calculations in full lattice QCD of the mass, leptonic\nwidth and radiative decay rate to eta_c of the J/psi meson. These provide few %\ntests of QCD. Another (1.5%) test comes from comparison of time-moments of the\nvector charmonium correlator with results derived from the experimental values\nof R(e+e- to hadrons) in the charm region.",
        "positive": "Nonperturbative Determination of Collins-Soper Kernel from Quasi\n  Transverse-Momentum Dependent Wave Functions: In the framework of large-momentum effective theory at one-loop matching\naccuracy, we perform a lattice calculation of the Collins-Soper kernel which\ngoverns the rapidity evolution of transverse-momentum-dependent (TMD)\ndistributions. We first obtain the quasi TMD wave functions at three different\nmeson momenta on a lattice with valence clover quarks on a dynamical HISQ sea\nand lattice spacing $a=0.12$~fm from MILC, and renormalize the pertinent linear\ndivergences using Wilson loops. Through one-loop matching to the light-cone\nwave functions, we determine the Collins-Soper kernel with transverse\nseparation up to 0.6~fm. We study the systematic uncertainties from operator\nmixing and scale dependence, as well as the impact from higher power\ncorrections. Our results potentially allow for a determination of the soft\nfunction and other transverse-momentum dependent quantities at one-loop\naccuracy."
    },
    {
        "anchor": "Heavy quark thermodynamics in full QCD: We analyze the large-distance behaviour of static quark-anti-quark pair\ncorrelations in QCD. The singlet free energy is calculated and the entropy\ncontribution to it is identified allowing us to calculate the excess internal\nenergy. The free energy has a sharp drop in the critical region, leading to\nsharp peaks in both excess entropy and internal energy.",
        "positive": "Generalising the Ginsparg-Wilson relation: Lattice Supersymmetry from\n  Blocking Transformations: The Ginsparg-Wilson relation is extended to interacting field theories with\ngeneral linear symmetries. Our relation encodes the remnant of the original\nsymmetry in terms of the blocked fields and guides the construction of\ninvariant lattice actions. We apply this approach in the case of lattice\nsupersymmetry. An additional constraint has to be satisfied because of the\nappearance of a derivative operator in the symmetry transformations. The\nsolution of this constraint leads to non-local SLAC-type derivatives. We\ninvestigate the corresponding kinetic operators on the lattice within an exact\nsolution of supersymmetric quantum mechanics. These solutions - analogues of\nthe overlap operator for supersymmetry - can be made local through a specific\nchoice of the blocking kernel. We show that the corresponding relation allows\nfor local lattice symmetry operators as well as local lattice actions. We argue\nthat for interacting theories the lattice action is polynomial in the fields\nonly under special circumstances, which is exemplified within an exact\nsolution."
    },
    {
        "anchor": "Latent heat of the large N finite temperature phase transition: Reduced large N gauge theories have a phase with unbroken center symmetry and\nphases in which that symmetry is broken for Polyakov loops in one or more\nlattice directions. The phase with unbroken symmetry is associated with the\nzero temperature, infinite volume, infinite N theory while the phase in which\nthe symmetry is broken in just one lattice direction has been conjectured to be\nthe spatial reduction of the high temperature, infinite volume, infinite N\ntheory. Measurements of the scaling properties of the latent heat of the\ntransition between these phases test that hypothesis. The results indicate a\nnon-zero latent heat in the continuum limit. Substantial finite spacing effects\nremain, and finer lattices will be needed to confirm physical scaling.",
        "positive": "Lattice Index Theorem and Fractional Topological Charge: We study topological properties of classical spherical center vortices with\nthe low-lying eigenmodes of the Dirac operator in the fundamental and adjoint\nrepresentations using both the overlap and asqtad staggered fermion\nformulations. In particular we address the puzzle raised in a previous work of\nour group [Phys.\\ Rev.\\ D 77, 14515 (2008)], where we found a violation of the\nlattice index theorem with the overlap Dirac operator in the fundamental\nrepresentation even for \"admissible\" gauge fields. Here we confirm the\ndiscrepancy between the topological charge and the index of the Dirac operator\nalso for asqtad staggered fermions and the adjoint representation. Numerically,\nthe discrepancy equals the sum of the winding numbers of the spheres when they\nare regarded as maps $\\mathbbm R^3 \\cup \\{\\infty\\} \\to SU(2)$. Furthermore we\nfind some evidence for fractional topological charge during cooling the\nspherical center vortex on a $40^3 \\times 2$ lattice. The object with\ntopological charge $Q=1/2$ we identify as a Dirac monopole with a gauge field\nfading away at large distances. Therefore even for periodic boundary conditions\nit does not need an antimonopole."
    },
    {
        "anchor": "Smearing Center Vortices: We smear Z(2) center vortices in lattice gauge configurations such as to\nrecover thick vortices with full SU(2) Yang-Mills information. In particular,\nwe address the problem that using Z(2) configurations in conjunction with\noverlap (or chirally improved) fermions is problematic due to their lack of\nsmoothness. Our method allows us to regain this smoothness and simultaneously\nmaintain the center vortex structure. We verify our method with various gluonic\nand fermionic observables and find good agreement between smeared vortex\nconfigurations and full SU(2).",
        "positive": "Disappearance of the Abrikosov vortex above the deconfining phase\n  transition in SU(2) lattice gauge theory: We calculate the solenoidal magnetic monopole current and electric flux\ndistributions at finite temperature in the presence of a static quark antiquark\npair. The simulation was performed using SU(2) lattice gauge theory in the\nmaximal Abelian gauge. We find that the monopole current and electric flux\ndistributions are quite different below and above the finite temperature\ndeconfining phase transition point and agree with predictions of the\nGinzburg-Landau effective theory."
    },
    {
        "anchor": "Nonperturbative Renormalization of the Quark Chromoelectric Dipole\n  Moment with the Gradient Flow:Power Divergences: The CP-violating quark chromoelectric dipole moment (qCEDM) operator,\ncontributing to the electric dipole moment (EDM), mixes under renormalization\nand particularly on the lattice with the pseudoscalar density. The mixing\ncoefficient is power-divergent with the inverse lattice spacing squared,\n$1/a^2$, regardless of the lattice action used. We use the gradient flow to\ndefine a multiplicatively renormalized qCEDM operator and study its behavior at\nsmall flow time. We determine nonperturbatively the linearly divergent\ncoefficient with the flow time, $1/t$, up to subleading logarithmic\ncorrections, and compare it with the 1-loop perturbative expansion in the bare\nand renormalized strong coupling. We also discuss the O($a$) improvement of the\nqCEDM defined at positive flow time.",
        "positive": "Coulomb string tension, asymptotic string tension, and the gluon chain: We compute, via numerical simulations, the non-perturbative Coulomb potential\nof pure SU(3) gauge theory in Coulomb gauge. We find that that the Coulomb\npotential scales nicely in accordance with asymptotic freedom, that the Coulomb\npotential is linear in the infrared, and that the Coulomb string tension is\nabout four times larger than the asymptotic string tension. We explain how it\nis possible that the asymptotic string tension can be lower than the Coulomb\nstring tension by a factor of four."
    },
    {
        "anchor": "Exotica and the Confining Flux: Recent developments in Quantum Chromodynamics (QCD) are reviewed on three\nmajor topics where nonperturbative gluon excitations of the QCD vacuum and the\nphysical properties of the confining flux play a central role: (1) New lattice\nresults on the spectrum and wave functions of heavy quark-antiquark molecules,\nknown as heavy hybrids, will be discussed. (2) Recent advances on the glueball\nspectrum in lattice QCD will be presented with some theoretical observations.\n(3) Progress in our understanding of the nonperturbative internal structure of\nthe confining flux and its excitation spectrum will be reported.",
        "positive": "Understanding Color Confinement: Some aspects are discussed of the mechanism of color confinement in QCD by\ncondensation of magnetic monopoles in the vacuum."
    },
    {
        "anchor": "On the SU(2)-Higgs Phase Transition: The properties of the Confinement-Higgs phase transition in the SU(2)-Higgs\nmodel with fixed modulus are investigated. We show that the system exhibits a\ntransient behavior up to L=24 along which the order of the phase transition\ncannot be discerned. To get stronger conclusions about this point, without\ngoing to prohibitive large lattice sizes, we have introduced a second\n(next-to-nearest neighbors) gauge-Higgs coupling, k2. On this extended\nparameter space we find a line of phase transitions which become increasely\nweaker as k2 tends to 0. The results point to a first order character for the\ntransition with the standard action (k2 = 0).",
        "positive": "Phase structure analysis of CP(N-1) model using Tensor renormalization\n  group: The phase structure of the lattice CP($N-1$) model in two dimensions is\nanalyzed by the tensor renormalization group (TRG) method. We focus on the case\n$N=2$ and compare the numerical result of the TRG method with that of the\nstrong-coupling analysis in the presence of the $\\theta$ term and investigate\nthe nature of the phase transition at $\\theta=\\pi$."
    },
    {
        "anchor": "Comparative Benchmarks of full QCD Algorithms: We report performance benchmarks for several algorithms that we have used to\nsimulate the Schr\"odinger functional with two flavors of dynamical quarks. They\ninclude hybrid and polynomial hybrid Monte Carlo with preconditioning. An\nappendix describes a method to deal with autocorrelations for nonlinear\nfunctions of primary observables as they are met here due to reweighting.",
        "positive": "On the Determination of Nonleptonic Kaon Decays from $K\\to\u03c0$ Matrix\n  Elements: The coupling constants of the order $p^2$ low-energy weak effective\nlagrangian can be determined from the $K\\to\\pi$ and $K\\to 0$ weak matrix\nelements, choosing degenerate quark masses for the first of these. However, for\ntypical values of quark masses in Lattice QCD computations, next-to-leading\n$O(p^4)$ corrections are too large to be ignored, and will need to be included\nin future analyses. Here we provide the complete $O(p^4)$ expressions for these\nmatrix elements obtained from Chiral Perturbation Theory, valid for partially\nquenched QCD with $N$ degenerate sea quarks. Quenched QCD corresponds to the\nspecial case N=0. We also discuss the role of the $\\eta'$ meson in some detail,\nand we give numerical examples of the size of chiral logarithms."
    },
    {
        "anchor": "QCDUtils: This manual describes a set of utilities developed for Lattice QCD\ncomputations. They are collectively called QCDUtils. They comprise a set of\nPython programs each of them with a specific function: download gauge ensembles\nfrom the public NERSC repository, convert between formats, split files by\ntime-slices, compile and run physics algorithms, generate visualizations in the\nform of VTK files, convert the visualizations into images, perform bootstrap\nanalysis of results, fit the results of the analysis, and plot those results.\nThese tools implement the typical workflow of most Lattice QCD computations and\nautomate it by enforcing filename conventions: the output of one tool is read\nby the next tool in the workflow. This manual is organized as a series of\nautonomous recipes which can be combined together.",
        "positive": "On the Viability of Lattice Perturbation Theory: In this paper we show that the apparent failure of QCD lattice perturbation\ntheory to account for Monte Carlo measurements of perturbative quantities\nresults from choosing the bare lattice coupling constant as the expansion\nparameter. Using instead ``renormalized'' coupling constants defined in terms\nof physical quantities, like the heavy-quark potential, greatly enhances the\npredictive power of lattice perturbation theory. The quality of these\npredictions is further enhanced by a method for automatically determining the\ncoupling-constant scale most appropriate to a particular quantity. We present a\nmean-field analysis that explains the large renormalizations relating lattice\nquantities, like the coupling constant, to their continuum analogues. This\nsuggests a new prescription for designing lattice operators that are more\ncontinuum-like than conventional operators. Finally, we provide evidence that\nthe scaling of physical quantities is asymptotic or perturbative already at\n$\\beta$'s as low as 5.7, provided the evolution from scale to scale is analyzed\nusing renormalized perturbation theory. This result indicates that reliable\nsimulations of (quenched) QCD are possible at these same low $\\beta$'s."
    },
    {
        "anchor": "Mitigating a discrete sign problem with extreme learning machines: An extreme learning machine is a neural network in which only the weights in\nthe last layer are changed during training; for such networks training can be\nperformed efficiently and deterministically. We use an extreme learning machine\nto construct a control variate that tames the sign problem in the classical\nIsing model at imaginary external magnetic field. Using this control variate,\nwe directly compute the partition function at imaginary magnetic field in two\nand three dimensions, yielding information on the positions of Lee-Yang zeros.",
        "positive": "On the determination of low-energy constants for $\u0394S=1$\n  transitions: We present our preliminary results for three-point correlation functions\ninvolving the operators entering the $\\Delta{S}=1$ effective Hamiltonian with\nan active charm quark, obtained using overlap fermions in the quenched\napproximation. This is the first computation carried out for valence quark\nmasses small enough so as to permit a matching to Quenched Chiral Perturbation\nTheory in the $\\epsilon$-regime. The commonly observed large statistical\nfluctuations are tamed by means of low-mode averaging techniques, combined with\nrestrictions to individual topological sectors. We also discuss the matching of\nthe resulting hadronic matrix elements to the effective low-energy constants\nfor $\\Delta{S}=1$ transitions. This involves (a) finite-volume corrections\nwhich can be evaluated at NLO in Quenched Chiral Perturbation Theory, and (b)\nthe short-distance renormalization of the relevant four-quark operators in\ndiscretizations based on the overlap operator. We discuss perturbative\nestimates for the renormalization factors and possible strategies for their\nnon-perturbative evaluation. Our results can be used to isolate the\nlong-distance contributions to the $\\Delta I=1/2$ rule, coming from physics\neffects around the intrinsic QCD scale."
    },
    {
        "anchor": "Phase structure of hot dense QCD by a histogram method: We study the phase structure of QCD at high temperature and density by\nlattice QCD simulations adopting a histogram method. The quark mass dependence\nand the chemical potential dependence of the nature of phase transition are\ninvestigated focusing on the probability distribution function (histogram). The\nshape of the distribution function changes with the quark mass and chemical\npotential. Through the shape of the distribution, the critical surface which\nseparates the first order transition and crossover regions in the heavy quark\nregion is determined for the (2+1)-flavor case. Moreover, we determined the\ncritical point at finite density for two-flavor QCD with an intermediate quark\nmass, using a Gaussian approximation of the complex phase distribution of the\nquark determinant. The chemical potential dependence of the critical quark mass\nis also evaluated in the situation where two light quarks and many massive\nquarks exist. We find that the first order transition region becomes wider with\nthe chemical potential in the many-flavor QCD.",
        "positive": "Case studies of near-conformal $\u03b2$-functions: We present updated results for the non-perturbative $\\beta$-function of SU(3)\ngauge theories with $N_f = 12$ or 10 massless flavors in the fundamental rep or\n$N_f = 2$ in the sextet rep, measured with staggered fermions. New data at\nfiner lattice spacing and our previously introduced method, the infinitesimal\n$\\beta$-function, strengthen the case that the $N_f = 12$ model has no infrared\nfixed point up to $g^2 = 7.2$. We show how underestimated cutoff dependence in\none domain wall study for $N_f = 10$ has been corrected, which is now\nconsistent with staggered results showing a monotonically increasing\n$\\beta$-function. A consistent theme is that too small volumes can lead to\napparent fixed points which vanish towards the continuum limit. We also apply\nthe infinitesimal $\\beta$-function method to the $N_f = 10$ model, finding\nconsistent behavior with the finite-step $\\beta$-function. Ongoing simulations\nand analysis for the sextet model confirm our previous results from weak to\nstrong coupling with a non-zero $\\beta$-function throughout, in quantitative\ndifference to Wilson fermion simulations~\\cite{Hasenfratz:2015ssa}."
    },
    {
        "anchor": "Fast evaluation and locality of overlap fermions: In order to construct improved overlap fermions, we start from a short ranged\napproximate Ginsparg-Wilson fermion and insert it into the overlap formula. We\nshow that its polynomial evaluation is accelerated considerably compared to the\nstandard Neuberger fermion. In addition the degree of locality is strongly\nimproved.",
        "positive": "Monopole Condensation and Color Confinement: New evidence is discussed of monopole condensation in the vacuum of SU(2) and\nSU(3) gauge theories. Monopoles defined by different abelian projections do\ncondense in the transition to the confined phase and show the same behavior.\nFor SU(2) critical indices are determined by finite size scaling analysis and\nthe results agree with the 3d Ising Model, as expected."
    },
    {
        "anchor": "The Microscopic Representation of Complex Macroscopic Phenomena\n  (Critical Slowing Down - A Blessing in Disguise): Many complex systems are representable as macroscopic set of elements which\ninteract by simple rules. The complex macroscopically relevant phenomena are\nthen the result of the generic emergence of a space-time multi-scale dynamics.\nCritical Slowing Down labels the emerging global features and describes their\ncomplex collective evolution. This paradigm is quite universal and extends to a\nvery wide range of systems and disciplines.",
        "positive": "The flux tube profile in full QCD: We measure the spatial distribution of all components of the color fields\nsurrounding a static quark antiquark pair in QCD with (2+1) HISQ flavors. We\nisolate the nonperturbative component of the longitudinal chromoelectric color\nfield responsible for the linear term in the confining potential."
    },
    {
        "anchor": "Reversibility Violation in the Hybrid Monte Carlo Algorithm: We investigate reversibility violations in the Hybrid Monte Carlo algorithm.\nThose violations are inevitable when computers with finite numerical precision\nare being used. In SU(2) gauge theory, we study the dependence of observables\non the size of the reversibility violations. While we cannot find any\nstatistically significant deviation in observables related to the simulated\nphysical model, algorithmic specific observables signal an upper bound for\nreversibility violations below which simulations appear unproblematic. This\nempirically derived condition is independent of problem size and parameter\nvalues, at least in the range of parameters studied here.",
        "positive": "Non-Perturbative Renormalisation of the Lattice $\u0394s=2$\n  Four-Fermion Operator: We compute the renormalised four-fermion operator $O^{\\Delta S=2}$ using a\nnon-perturbative method recently introduced for determining the renormalisation\nconstants of generic lattice composite operators. Because of the presence of\nthe Wilson term, $O^{\\Delta S=2}$ mixes with operators of different\nchiralities. A projection method to determine the mixing coefficients is\nimplemented. The numerical results for the renormalisation constants have been\nobtained from a simulation performed using the SW-Clover quark action, on a\n$16^3 \\times 32$ lattice, at $\\beta=6.0$. We show that the use of the constants\ndetermined non-perturbatively improves the chiral behaviour of the lattice kaon\nmatrix element $\\<\\bar K^0| O^{\\Delta S=2} | K^0\\>_{\\latt}$."
    },
    {
        "anchor": "Universal formula for the flavor non-singlet axial-vector current from\n  the gradient flow: By employing the gradient/Wilson flow, we derive a universal formula that\nexpresses a correctly normalized flavor non-singlet axial-vector current of\nquarks. The formula is universal in the sense that it holds independently of\nregularization and especially holds with lattice regularization. It is also\nconfirmed that, in the lowest non-trivial order of perturbation theory, the\ntriangle diagram containing the formula and two flavor non-singlet vector\ncurrents possesses non-local structure that is compatible with the triangle\nanomaly.",
        "positive": "Coordinate-space calculation of the window observable for the hadronic\n  vacuum polarization contribution to $(g-2)_\u03bc$: The `intermediate window quantity' of the hadronic vacuum polarization\ncontribution to the anomalous magnetic moment of the muon allows for a\nhigh-precision comparison between the data-driven approach and lattice QCD. The\nexisting lattice results, which presently show good consistency among each\nother, are in strong tension with the data-driven determination. In order to\ncheck for a potentially common source of systematic error of the lattice\ncalculations, which are all based on the time-momentum representation (TMR), we\nperform a calculation using a Lorentz-covariant coordinate-space (CCS)\nrepresentation. We present results for the isovector and the connected\nstrange-quark contributions to the intermediate window quantity at a reference\npoint in the $(m_\\pi,m_K)$ plane, in the continuum and infinite-volume limit,\nbased on four different lattice spacings. Our results are in good agreement\nwith those of the recent TMR-based Mainz-CLS publication."
    },
    {
        "anchor": "Neutron and proton electric dipole moments from $N_f=2+1$ domain-wall\n  fermion lattice QCD: We present a lattice calculation of the neutron and proton electric dipole\nmoments (EDM's) with $N_f=2+1$ flavors of domain-wall fermions. The neutron and\nproton EDM form factors are extracted from three-point functions at the\nnext-to-leading order in the $\\theta$ vacuum of QCD. In this computation, we\nuse pion masses 0.33 and 0.42 GeV and 2.7 fm$^3$ lattices with Iwasaki gauge\naction and a 0.17 GeV pion and 4.6 fm$^3$ lattice with I-DSDR gauge action, all\ngenerated by the RBC and UKQCD collaborations. The all-mode-averaging technique\nenables an efficient and high statistics calculation. Chiral behavior of\nlattice EDM's is discussed in the context of baryon chiral perturbation theory.\nIn addition, we also show numerical evidence on relationship of three- and\ntwo-point correlation function with local topological distribution.",
        "positive": "Low-energy $D^{*+}D^0_1$ Scattering and the Resonance-like Structure\n  $Z^+(4430)$: Low-energy scattering of $D^*$ and $D_1$ meson are studied using quenched\nlattice QCD with improved lattice actions on anisotropic lattices. The\ncalculation is performed within L\\\"uscher's finite-size formalism which\nestablishes the relation between the scattering phase in the infinite volume\nand the exact energy level in the finite volume. The threshold scattering\nparameters, namely the scattering length $a_0$ and the effective range $r_0$,\nfor the s-wave scattering in $J^P=0^-$ channel are extracted. After the chiral\nand continuum extrapolations, we obtain: $a_0=2.52(47)$fm and $r_0=0.7(1)$fm\nwhere the errors are purely statistical. Based on these results, we discuss the\npossibility of a shallow bound state for the two charmed mesons within the\nnon-relativistic potential scattering model. It is argued that, albeit the\ninteraction between the two charmed mesons being attractive, it is unlikely\nthat they can form a shallow bound state in this channel. This calculation\nprovides some useful information on the nature of the newly discovered\nresonance-like structure $Z^+(4430)$ by the Belle Collaboration."
    },
    {
        "anchor": "Lattice field theory with torsion: Inspired by the duality between gravity and defects in crystals, we study\nlattice field theory with torsion. The torsion is realized by a line defect of\na lattice, namely a dislocation. As the first application, we perform the\nnumerical computation for vector and axial currents induced by a screw\ndislocation. This current generation is called the chiral torsional effect. We\nalso derive the analytical formula for the chiral torsional effect in the\ncontinuum limit.",
        "positive": "Scalar fields on fluctuating hyperbolic geometries: We present results on the behavior of the boundary-boundary correlation\nfunction of scalar fields propagating on discrete two-dimensional random\ntriangulations representing manifolds with the topology of a disk. We use a\ngravitational action that includes a curvature squared operator, which favors a\nregular tessellation of hyperbolic space for large values of its coupling. We\nprobe the resultant geometry by analyzing the propagator of a massive scalar\nfield and show that the conformal behavior seen in the uniform hyperbolic space\nsurvives as the coupling approaches zero. The analysis of the boundary\ncorrelator suggests that holographic predictions survive, at least, weak\nquantum gravity corrections. We then show how such an $R^2$ operator might be\ninduced as a result of integrating out massive lattice fermions and show\npreliminary result for boundary correlation functions that include the effects\nof this fermionic backreaction on the geometry."
    },
    {
        "anchor": "Two-current transition amplitudes with two-body final states: We derive the on-shell form of amplitudes containing two external currents\nwith a single hadron in the initial state and two hadrons in the final state,\ndenoted as $1+\\mathcal{J}\\to 2+\\mathcal{J}$. This class of amplitude is\nrelevant in precision tests of the Standard Model as well as for exploring the\nstructure of excited states in the QCD spectrum. We present a model-independent\ndescription of the amplitudes where we sum to all orders in the strong\ninteraction. From this analytic form we are able to extract transition and\nelastic resonance form factors consistent with previous work as well as a novel\nCompton-like amplitude coupling a single particle state to a resonance. The\nresults also hold for reactions where the one-particle state is replaced with\nthe vacuum, namely $\\mathcal{J}\\to 2+\\mathcal{J}$ amplitudes. We also\ninvestigate constraints placed upon the formalism for the case of a conserved\nvector current in the form of the Ward-Takahashi identity. The formalism\npresented here is valid for currents of arbitrary Lorentz structure and quantum\nnumbers with spinless hadrons where any number of two-particle intermediate\nchannels may be open. When combined with the appropriate finite-volume\nframework, this work facilitates the extraction of physical observables from\nthis class of amplitudes via lattice QCD calculations.",
        "positive": "Resonance form factors from finite-volume correlation functions with the\n  external field method: A novel method for the extraction of form factors of unstable particles on\nthe lattice is proposed. The approach is based on the study of two-particle\nscattering in a static, spatially periodic external field by using a\ngeneralization of the L\\\"uscher method in the presence of such a field. It is\nshown that the resonance form factor is given by the derivative of the\nresonance pole position in the complex plane with respect to the coupling\nconstant to the external field. Unlike the standard approach, this proposal\ndoes not suffer from problems caused by the presence of the triangle diagram."
    },
    {
        "anchor": "A non-perturbative study of the action parameters for\n  anisotropic-lattice quarks: A quark action designed for highly anisotropic lattice simulations is\ndiscussed. The mass-dependence of the parameters in the action is studied and\nthe results are presented. Applications of this action in studies of heavy\nquark quantities are described and results are presented from simulations at an\nanisotropy of six, for a range of quark masses from strange to bottom.",
        "positive": "Exploring a new SU(4) symmetry of meson interpolators: In recent lattice calculations it has been discovered that mesons upon\ntruncation of the quasi-zero modes of the Dirac operator obey a symmetry larger\nthan the $SU(2)_L \\times SU(2)_R\\times U(1)_A$ symmetry of the QCD Lagrangian.\nThis symmetry has been suggested to be $SU(4) \\supset SU(2)_L \\times\nSU(2)_R\\times U(1)_A$ that mixes not only the u- and d-quarks of a given\nchirality, but also the left- and right-handed components. Here it is\ndemonstrated that bilinear $\\overline{q}q$ interpolating fields of a given spin\n$J \\geq 1$ transform into each other according to irreducible representations\nof $SU(4)$ or, in general, $SU(2N_F)$. This fact together with the coincidence\nof the correlation functions establishes $SU(4)$ as a symmetry of the $J \\geq\n1$ mesons upon quasi-zero mode reduction. It is shown that this symmetry is a\nsymmetry of the confining instantaneous charge-charge interaction in QCD.\nDifferent subgroups of $SU(4)$ as well as the $SU(4)$ algebra are explored."
    },
    {
        "anchor": "Multi-Representation Dynamics of SU(4) Composite Higgs Models: Chiral\n  Limit and Spectral Reconstructions: We present a lattice study of the $SU(4)$ gauge theory with two Dirac\nfermions in the fundamental and two in the two-index antisymmetric\nrepresentation, a model close to a theory of partial compositeness. Focus of\nthis work are the methodologies behind the computation of the spectrum and the\nextrapolation of the chiral point for a theory with matter in multiple\nrepresentations. While being still technical, this study provides important\nsteps towards a non-perturbative understanding of the spectrum of theories of\npartial compositeness, which present a richer dynamics compared to\nsingle-representation theories. The multi-representation features are studied\nfirst in perturbation theory, and then non-perturbatively by adopting a dual\noutlook on lattice data through a joint analysis of time-momentum correlation\nfunctions and smeared spectral densities.",
        "positive": "Error reduction using machine learning on Ising worm simulation: We develop a method to improve on the statistical errors for higher moments\nusing machine learning techniques. We present here results for the dual\nrepresentation of the Ising model with an external field, derived via the high\ntemperature expansion and simulated by the worm algorithm. We compare two ways\nof measuring the same set of observables, without and with machine learning:\nmoments of the magnetization and the susceptibility can be improved by using\nthe decision tree method to train the correlations between the higher moments\nand the second moment obtained from an integrated 2-point function. Those\nresults are compared in small volumes to analytic predictions."
    },
    {
        "anchor": "Charmonium Spectroscopy From Lattice NRQCD: We present the first set of results for Charmonium Spectroscopy using\nNon-Relativistic QCD (NRQCD). For the NRQCD action the leading order\nspin-dependent and next to leading order spin-independent interactions have\nbeen included. Clear signals for the s and p hyperfine splittings have been\nobserved as well as various orbital states.",
        "positive": "Coulomb Confinement from the Yang-Mills Vacuum State in 2+1 Dimensions: The Coulomb-gauge ghost propagator, and the color-Coulomb potential, are\ncomputed in an ensemble of configurations derived from our recently proposed\nYang-Mills vacuum wavefunctional in 2+1 dimensions. The results are compared to\nthe corresponding values obtained by standard Monte Carlo simulations in three\nEuclidean dimensions. The agreement is quite striking for the Coulomb-gauge\nghost propagator. The color-Coulomb potential rises linearly at large\ndistances, but its determination suffers from rather large statistical\nfluctuations, due to configurations with very low values of $\\mu_0$, the lowest\neigenvalue of the Coulomb-gauge Faddeev-Popov operator. However, if one imposes\ncuts on the data, effectively leaving out configurations with very low $\\mu_0$,\nthe agreement of the potential in both sets of configurations is again\nsatisfactory, although the errorbars grow systematically as the cutoff is\neliminated."
    },
    {
        "anchor": "Deconfinement Phase Transition in Bosonic BMN Model at General Coupling: We present our analysis of the deconfinement phase transition in the bosonic\nBMN matrix model. The model is investigated using a non-perturbative lattice\nframework. We used the Polyakov loop as the order parameter to monitor the\nphase transition, and the results were verified using the separatrix ratio. The\ncalculations are performed using a large number of colors and a broad range of\ntemperatures for all couplings. Our results indicate a first-order phase\ntransition in this theory for all the coupling values that connect the\nperturbative and non-perturbative regimes of the theory.",
        "positive": "Enumerating Copies in the First Gribov Region on the Lattice in up to\n  four Dimensions: The covariant gauges are known to suffer from the Gribov problem: even after\nfixing a gauge non-perturbatively, there may still exist residual copies which\nare physically equivalent to each other, called Gribov copies. While the\ninfluence of Gribov copies in the relevant quantities such as gluon propagators\nhas been heavily debated in recent studies, the significance of the role they\nplay in the Faddeev--Popov procedure is hardly doubted. We concentrate on\nGribov copies in the first Gribov region, i.e., the space of Gribov copies at\nwhich the Faddeev--Popov operator is strictly positive (semi)definite. We\ninvestigate compact U($1$) as the prototypical model of the more complicated\nstandard model group SU($N_{c}$). With our Graphical Processing Unit (GPU)\nimplementation of the relaxation method we collect up to a few million Gribov\ncopies per orbit. We show that the numbers of Gribov copies even in the first\nGribov region increase exponentially in two, three and four dimensions.\nFurthermore, we provide strong indication that the number of Gribov copies is\ngauge orbit dependent."
    },
    {
        "anchor": "Stochastic computation of $g-2$ in QED: We perform a numerical computation of the anomalous magnetic moment ($g-2$)\nof the electron in QED by using the stochastic perturbation theory. Formulating\nQED on the lattice, we develop a method to calculate the coefficients of the\nperturbative series of $g-2$ without the use of the Feynman diagrams. We\ndemonstrate the feasibility of the method by performing a computation up to the\n$\\alpha^3$ order and compare with the known results. This program provides us\nwith a totally independent check of the results obtained by the Feynman\ndiagrams and will be useful for the estimations of not-yet-calculated higher\norder values. This work provides an example of the application of the numerical\nstochastic perturbation theory to physical quantities, for which the external\nstates have to be taken on-shell.",
        "positive": "Recent lattice results on finite temerature and density QCD, part II: We discuss recent progress in studies of QCD thermodynamics with almost\nphysical light quark masses and a physical value of the strange quark mass. We\nsummarize results on the transition temperature in QCD and analyze the relation\nbetween deconfinement and chiral symmetry restoration."
    },
    {
        "anchor": "Message passing on the QCDSP supercomputer: The QCDSP machines were designed for lattice gauge calculations. For planning\nit is crucial to explore this architecture for other computationally intensive\ntasks. Here I describe an implementation of a simple message passing scheme.\nWith the objective being simplicity, I introduce a small number of generic\nfunctions for manipulating a large data set spread over the machine. I test the\nscheme on three applications: a fast Fourier transform, arbitrary dimension\nSU(N) pure lattice gauge theory, and the manipulation of Fermionic Fock states\nthrough a distributed hash table. These routines compile both on QCDSP and a\nUnix workstation.",
        "positive": "The rho meson decay constant using a tadpole-improved action: The rho meson decay constant and the associated renormalization factor are\ncomputed in the quenched approximation on coarse lattices using a\ntadpole-improved action which is corrected at the classical level to O(a^2).\nThe improvement is displayed by comparing to Wilson action calculations."
    },
    {
        "anchor": "On the Structure of the Yang-Mills Vacuum: In this talk I will discuss the current picture of color confinement. In\nparticular, I will show how it can be tested microscopically. It is stressed\nthat the color magnetic monopoles in this picture are dyons. Furthermore, the\nrole of instantons is illuminated.",
        "positive": "Electrical conductivity of the quark-gluon plasma: perspective from\n  lattice QCD: A discussion on the electrical conductivity of the quark-gluon plasma as\ndetermined by lattice QCD is given. After a reminder of basic definitions and\nexpectations, various methods for spectral reconstruction are reviewed,\nincluding the use of Ans\\\"atze and sum rules, the Maximum Entropy and\nBackus-Gilbert methods, and Tikhonov regularisation. A comprehensive overview\nof lattice QCD results obtained so far is given, including a comparison of the\ndifferent lattice formulations. A noticeable consistency for the conductivities\nobtained is seen, in spite of the differences in the lattice setups and\nspectral reconstruction methods. It is found that in the case of quenched QCD\nlittle temperature dependence of $\\sigma/T$ is seen in the temperature range\ninvestigated, while for QCD with dynamical quarks a reduction of $\\sigma/T$ in\nthe vicinity of the thermal crossover is observed, compared to its value in the\nQGP. Several open questions are posed at the end."
    },
    {
        "anchor": "Lee-Yang edge singularities in 2+1 flavor QCD with imaginary chemical\n  potential: We present results of the location of the closest singularities in the\ncomplex chemical potential plane using a novel method. These results are\nobtained with (2+1)-flavor of highly improved staggered quarks (HISQ) on\nlattices with temporal extent of Nt=4,6. We show that the scaling is consistent\nwith the expected scaling of the Lee-Yang edge singularities in the vicinity of\nthe Roberge-Weiss (RW) transition. We determine various non-universal\nparameters using 3D Ising model scaling functions that map QCD in the scaling\nregion of the RW transition. Furthermore, as a preliminary result we discuss\nhow the Lee-Yang edge singularity can be used to probe the chiral phase\ntransition in QCD. The singularity obtained close to the chiral phase\ntransition temperature Tc seems to be in agreement with the expected scaling of\nthe Lee-Yang edge singularity. As an outlook, we discuss the scaling of the\nLee-Yang edge singularity in the vicinity of a possible critical end point in\nQCD, at even lower temperatures. In the future, such a scaling analysis might\nhint on the existence and the location of the critical end point. The work\npresented here is a part of an ongoing project of Bielefeld Parma joint\ncollaboration.",
        "positive": "$B \\to D^* l \u03bd$ with staggered chiral perturbation theory: An unquenched calculation of the form factor for $B\\to D^* l \\nu$ is needed\nto improve the determination of $|V_{cb}|$. The MILC lattices, computed with a\n2+1 improved staggered action for the light quarks, are well suited to this\npurpose. The relevant staggered chiral perturbation theory (SChPT) must be\nknown in order to correctly account for the \"taste\" breaking discretization\neffects associated with the staggered quarks to NLO in $1/ m_{D^*}$. This SChPT\ncalculation is presented."
    },
    {
        "anchor": "Numerical Studies of the Double Scaling Limit in Large N Reduced Model: We study the two-dimensional Eguchi-Kawai model as a toy model of the IIB\nmatrix model, which has been recently proposed as a nonperturbative definition\nof the type IIB superstring theory. While the planar limit of the model is\nknown to reproduce the two-dimensional Yang-Mills theory, we find through Monte\nCarlo simulation that the model allows a different large $N$ limit, which can\nbe considered as the double scaling limit in matrix models.",
        "positive": "Searching for Yang-Lee zeros in O($N$) models: Near the second order phase transition point, QCD with two flavours of\nmassless quarks can be approximated by an O($4$) model, where a symmetry\nbreaking external field $H$ can be added to play the role of quark mass. The\nLee-Yang theorem states that the equation of state in this model has a branch\ncut along the imaginary $H$ axis for $|Im[H]|>H_c$, where $H_c$ indicates a\nsecond order critical point. This point, known as Lee-Yang edge singularity, is\nof importance to the thermodynamics of the system. We report here on ongoing\nwork to determine the location of $H_c$ via complex Langevin simulations."
    },
    {
        "anchor": "Making use of the International Lattice Data Grid: The International Lattice Data Grid (ILDG) continues stable operation for\nabout one year and has accumulated a lot of valuable configurations. After a\nbrief review of the ILDG system, we highlight large physics projects, whose\nconfigurations are already available on the grid or will be open to the public\nin the near future. With such information, one can make better use of the ILDG.\nStatistics about the ILDG is also reported.",
        "positive": "Grid: A next generation data parallel C++ QCD library: In this proceedings we discuss the motivation, implementation details, and\nperformance of a new physics code base called Grid. It is intended to be more\nperformant, more general, but similar in spirit to QDP++\\cite{QDP}. Our\napproach is to engineer the basic type system to be consistently fast, rather\nthan bolt on a few optimised routines, and we are attempt to write all our\noptimised routines directly in the Grid framework. It is hoped this will\ndeliver best known practice performance across the next generation of\nsupercomputers, which will provide programming challenges to traditional scalar\ncodes.\n  We illustrate the programming patterns used to implement our goals, and\nadvances in productivity that have been enabled by using new features in C++11."
    },
    {
        "anchor": "Properties of phase transitions of higher order: There is only limited experimental evidence for the existence in nature of\nphase transitions of Ehrenfest order greater than two. However, there is no\nphysical reason for their non-existence, and such transitions certainly exist\nin a number of theoretical models in statistical physics and lattice field\ntheory. Here, higher-order transitions are analysed through the medium of\npartition function zeros. Results concerning the distributions of zeros are\nderived as are scaling relations between some of the critical exponents.",
        "positive": "Gauge-invariant strings in the 3d U(1)+Higgs theory: We describe how the strings, which are classical solutions of the continuum\nthree-dimensional U(1)+Higgs theory, can be studied on the lattice. The effect\nof an external magnetic field is also discussed and the first results on the\nstring free energy are presented. It is shown that the string free energy can\nbe used as an order parameter when the scalar self-coupling is large and the\ntransition is continuous."
    },
    {
        "anchor": "Colour fields in gauge invariant quenched SU(3) Lattice QCD: he colour fields, created by static sources belonging to different SU(3)\nrepresentations, from the 3 to the 27, are computed in quenched SU(3) lattice\nQCD, in a 24^3 x 48 lattice at beta=6.2 and a=0.07261(85) fm. We utilize the\ntechnique of generalized Wilson Loops to localize the sources, correlated with\nplaquettes to measure the respective colour fields. We investigate the Casimir\nscaling of the fields, measured in the static potentials by Bali. We also study\nthe coherence length, comparing with the dual Ginzburg-Landau approach. With\nthe penetration and coherence lengths we determined the Ginzburg-Landau\ndimensionless parameter, this result is consistent with a type II\nsuperconductor picture, and with an effective dual gluon mass of 0.905 +- 0.163\nGeV.",
        "positive": "The gradient flow coupling in the Schr\u00f6dinger Functional: We study the perturbative behavior of the Yang-Mills gradient flow in the\nSchr\\\"odinger Functional, both in the continuum and on the lattice. The energy\ndensity of the flow field is used to define a running coupling at a scale given\nby the size of the finite volume box. From our perturbative computation we\nestimate the size of cutoff effects of this coupling to leading order in\nperturbation theory. On a set of Nf=2 gauge field ensembles in a physical\nvolume of L ~ 0.4 fm we finally demonstrate the suitability of the coupling for\na precise continuum limit due to modest cutoff effects and high statistical\nprecision."
    },
    {
        "anchor": "Progress in lattice algorithms: The development of Monte Carlo algorithms for generating gauge field\nconfigurations with dynamical fermions and methods for extracting the most\ninformation from ensembles are summarised.",
        "positive": "From Monte Carlo Integration to Quantum Chromo Dynamics (an\n  introduction): In these lectures we provide a short introduction to the Monte Carlo\nintegration method and its applications. We show how the origin of ultraviolet\ndivergences if Field Theories is in the undefined formal product of\ndistributions and how one can define the Path Integral in terms of regularized\ndistributions in order to cancel these divergences. This technique provides the\nonly non perturbative regularization procedure of continuum Field Theories and,\nat the same time, provides a practical method to compute correlation (Green)\nfunctions (using Monte Carlo integration for the regularized path integrals).\nWe then apply these tools to formulate QCD on a lattice. Some of the examples\nare accompanied by complete computer programs."
    },
    {
        "anchor": "'t Hooft Loops, Electric Flux Sectors and Confinement in SU(2)\n  Yang-Mills Theory: We use 't Hooft loops of maximal size on finite lattices to calculate the\nfree energy in the sectors of SU(2) Yang-Mills theory with fixed electric flux\nas a function of temperature and (spatial) volume. Our results provide evidence\nfor the mass gap. The confinement of electric fluxes in the low temperature\nphase and their condensation in the high temperature phase are demonstrated. In\na surprisingly large scaling window around criticality, the transition is\nquantitatively well described by universal exponents and amplitude ratios\nrelating the properties of the two phases.",
        "positive": "Particle-dimer approach for the Roper resonance in a finite volume: We propose a new finite-volume approach which implements two- and three-body\ndynamics in a transparent way based on an Effective Field Theory Lagrangian.\nThe formalism utilizes a particle-dimer picture and formulates the quantization\nconditions based on the self-energy of the decaying particle. The formalism is\nstudied for the case of the Roper resonance, using input from lattice QCD and\nphenomenology. Finally, finite-volume energy eigenvalues are predicted and\ncompared to existing results of lattice QCD calculations. This crucially\nprovides initial guidance on the necessary level of precision for the\nfinite-volume spectrum."
    },
    {
        "anchor": "Investigation of the Critical Behavior of the Critical Point of the Z2\n  Gauge Lattice: We investigate, through Monte-Carlo simulations, the nature of the second\norder point in a $Z_2$ (Bosonic) + $Z_2$ gauge theory in four dimensions.\nDetailed analysis of the critical exponents point to the Ising universality\nclass. Relevancy to extended models and possible Non-Gaussian behavior is\ndiscussed.",
        "positive": "Prospects for the stout smearing as an equivalent approach to the Wilson\n  flow: We present the equivalence between the Wilson flow and the stout smearing.\nThe similarity between these two methods was first pointed out by L\\\"uscher's\noriginal paper on the Wilson flow. We first show the analytical equivalence of\ntwo methods, which indicates that the finite stout smearing parameter induces\n${\\cal O}(a^2)$ correction. We secondly show that they remain equivalent in\nnumerical simulations within some numerical precision even with finite cutoffs\nand stout smearing parameters by directly comparing the expectation values of\nthe action density and we shortly mention the use of the equivalence."
    },
    {
        "anchor": "Twisted mass QCD for weak matrix elements: I report on the application of tmQCD techniques to the computation of\nhadronic matrix elements of four-fermion operators. Emphasis is put on the\ncomputation of $B_K$ in quenched QCD performed by the ALPHA Collaboration. The\nextension of tmQCD strategies to the study of neutral $B$-meson mixing is\nbriefly discussed. Finally, some remarks are made concerning proposals to apply\ntmQCD to the computation of $K\\to\\pi\\pi$ amplitudes.",
        "positive": "Photon operators for lattice gauge theory: Photon operators with the proper $J^{PC}$ quantum numbers are constructed,\nincluding one made of elementary plaquettes. In compact U(1) lattice gauge\ntheory, these explicit photon operators are shown to permit direct confirmation\nof the massive and massless states on each side of the phase transition. In the\nabelian Higgs model, these explicit photon operators avoid some excited state\ncontamination seen with the traditional composite operator, and allow more\ndetailed future studies of the Higgs mechanism."
    },
    {
        "anchor": "B $\\to$ $\u03c0$ form factor with 2 flavours of $O(a)$ improved Wilson\n  quarks: The determinations of $|V_{\\rm ub}|$ from the exclusive branching ratios of\n$B\\to \\tau \\nu$ and $B \\to \\pi l \\nu$ tend to show a tension at the level of\n$3\\sigma$ \\cite{Beringer:1900zz}. On the theoretical side they depend on the\nlattice computation of the hadronic matrix elements $f_{\\rm B}$ and the $B\\to\n\\pi$ form factor $f_+(q^2)$. To understand the tension, improved precision and\na careful analysis of the systematics involved are necessary. Working towards\nthis goal, we present preliminary lattice results of the ALPHA collaboration\nfor the $B\\to \\pi$ form factor $f_+(q^2)$ with $N_{\\rm f}=2$ flavours of\n$O(a)$-improved Wilson fermions. Our computation uses HQET in the static limit,\npion masses ranging down to $\\sim250$ MeV, large volumes with $m_\\pi L >4$,\nthree lattice spacings, and non-perturbative renormalization. We describe the\ntechniques adopted to reduce the statistical noise (stochastic all-to-all with\nfull time dilution) and the contamination from excited states (smearing for the\nB and the pion). We estimate the size of the chiral and continuum\nextrapolations. We discuss the impact our result could have to clarify the\nabove mentioned discrepancy in the determination of $|V_{\\rm ub}|$.",
        "positive": "Lattice Calculation of D- and B-meson Semileptonic Decays, using the\n  Clover Action at beta=6.0 on APE: We present the results of a high statistics lattice calculation of hadronic\nform factors relevant for $D-$ and $B-$meson semi-leptonic decays into light\npseudoscalar and vector mesons. The results have been obtained by averaging\nover 170 gauge field configurations, generated in the quenched approximation,\nat $\\beta=6.0$, on a $18^3 \\times 64$ lattice, using the $O(a)$-improved\nSW-Clover action.From the study of the matrix element $<K^-\\vert J_\\mu \\vert\nD^0>$, we obtain $f_+ (0)=0.78\\pm 0.08$ and from the matrix element $<\\bar K^{*\n0}\\vert J_\\mu \\vert D^+>$ we obtain $V(0)=1.08\\pm 0.22$, $A_1(0)=0.67\\pm 0.11$\nand $A_2(0)=0.49\\pm 0.34$. We also obtain the ratios $V(0)/A_1(0)=1.6\\pm 0.3$\nand $A_2(0)/A_1(0)= 0.7\\pm 0.4$. Our predictions for the different form factors\nare in good agreement with the experimental data, although, in the case of\n$A_2(0)$, the errors are still too large to draw any firm conclusion. With the\nhelp of the Heavy Quark Effective Theory (HQET) we have also extrapolated the\nlattice results to $B$-meson decays. The form factors follow a behaviour\ncompatible with the HQET predictions. Our results are in agreement with a\nprevious lattice calculation, performed at $\\beta=6.4$, using the standard\nWilson action."
    },
    {
        "anchor": "New Phases of SU(3) and SU(4) at Finite Temperature: The addition of an adjoint Polyakov loop term to the action of a pure gauge\ntheory at finite temperature leads to new phases of SU(N) gauge theories. For\nSU(3), a new phase is found which breaks Z(3) symmetry in a novel way; for\nSU(4), the new phase exhibits spontaneous symmetry breaking of Z(4) to Z(2),\nrepresenting a partially confined phase in which quarks are confined, but\ndiquarks are not. The overall phase structure and thermodynamics is consistent\nwith a theoretical model of the effective potential for the Polyakov loop based\non perturbation theory.",
        "positive": "Domain-wall and overlap fermions at nonzero quark chemical potential: We have recently given a construction of the overlap Dirac operator at\nnonzero quark chemical potential. Here, we introduce a quark chemical potential\nin the domain-wall fermion formalism and show that our earlier result is\nreproduced if the extent of the fifth dimension is taken to infinity and its\nlattice spacing is taken to zero. We also extend this result to include a bare\nquark mass, consider its continuum limit, and prove a number of properties of\nthe overlap operator at nonzero quark chemical potential. In particular, we\nshow that the relation between the anomaly and the index of the overlap\noperator remains valid."
    },
    {
        "anchor": "Determining the low energy parameters of Wilson Chiral Perturbation\n  Theory: We report preliminary results of a Wilson Chiral Perturbation Theory (WChPT)\nanalysis of twisted mass lattice QCD data. The quenched data, previously\npublished by two different groups, was generated with two definitions for the\ncritical quark mass and shows a strong non-linear quark mass dependence for\nsmall quark masses for the pion mass definition (``bending phenomenon''). We\nfind that WChPT describes this characteristic curvature fairly well. Fits to\nthe data provide estimates for combinations of low-energy parameters, even\nthough the errors are sizable.",
        "positive": "Exact Nonperturbative Renormalization: We propose an exact renormalization group equation for Lattice Gauge\nTheories, that has no dependence on the lattice spacing. We instead relate the\nlattice spacing properties directly to the continuum convergence of the support\nof each local plaquette. Equivalently, this is formulated as a convergence\nprescription for a characteristic polynomial in the gauge coupling that allows\nthe exact meromorphic continuation of a nonperturbative system arbitrarily\nclose to the continuum limit."
    },
    {
        "anchor": "Leading-order hadronic contributions to the electron and tau anomalous\n  magnetic moments: The leading hadronic contributions to the anomalous magnetic moments of the\nelectron and the $\\tau$-lepton are determined by a four-flavour lattice QCD\ncomputation with twisted mass fermions. The continuum limit is taken and\nsystematic uncertainties are quantified. Full agreement with results obtained\nby phenomenological analyses is found.",
        "positive": "Exploring free-form smearing for bottomonium and B meson spectroscopy: Free-form smearing was designed as a way to implement source operators of any\ndesired shape. A variation of the method is introduced that reduces the\ncomputational cost by reducing the number of link multiplications to its\nabsolute minimum. Practical utility is demonstrated through calculations of\nbottomonium and B meson masses."
    },
    {
        "anchor": "Topological susceptibility in full QCD at zero and finite temperature: We present a study of the topological susceptibility $\\chi$ on the lattice\nfor full QCD with 2 and 4 flavours of staggered fermions at zero and finite\ntemperature T. We find that $\\chi$ presents a sharp drop across the\ndeconfinement transition. We also study the dependence of $\\chi$ on the quark\nmass at T=0: we have no conclusive evidence for the expected chiral behaviour.",
        "positive": "The Thermal Width of the Glueball at Non-Zero Temperature: We use SU(3) anisotropic lattice QCD at quenched level to study the 0++\nglueball correlator at various temperature taking into account the possible\nexistence of the thermal width in the ground-state peak. For this purpose, we\nadopt the Breit-Wigner ansatz for the appropriate fit-function for the lattice\ndata obtained with 5,500-9,900 gauge configurations at each T. The results show\nthe significant thermal width broadening as Gamma(T_c) \\sim 300 MeV with a\nreduction in the peak center as Delta omega_0(T_c) \\sim 100 MeV near the\ncritical temperature T_c."
    },
    {
        "anchor": "Pion mass splitting and phase structure in Twisted Mass QCD: In the framework of Wilson Chiral Perturbation Theory, we study the effect\ninduced by a twisted Wilson term, as it appears in Twisted Mass QCD (with 2\ndegenerate quarks). In particular we consider the vacuum orientation and the\npion masses. The computations are done to NLO both in the mass and in the\nlattice spacing (i.e. to O(a^2)). There are no restrictions on the relative\nsize of lattice artifacts with respect to the physical mass, thus allowing, in\nprinciple, to bridge between the physical regime and the unphysical one, where\nlattice artifacts tend to dominate. The inclusion of O(a^2) lattice artifacts\ncan account for the splitting of degeneracy of the three pion masses. Moreover\nO(a^2) terms are necessary to model non trivial behaviors of the vacuum\norientation such as possible Aoki phases. It turns out that these last two\nphenomena are determined by the same constant.",
        "positive": "Supersymmetric Yang-Mills theory on the lattice: Recent development in numerical simulations of supersymmetric Yang-Mills\n(SYM) theories on the lattice is reviewed."
    },
    {
        "anchor": "The phase diagram of the three-dimensional Z2 gauge Higgs system at zero\n  and finite temperature: We study the effect of adding a matter field to the Z2 gauge model in three\ndimensions at zero and finite temperature. Up to a given value of the parameter\nregulating the coupling, the matter field produces a slight shift of the\ntransition line without changing the universality class of the pure gauge\ntheory, as seen by finite size scaling analysis or by comparison, in the finite\ntemperature case, to exact formulas of conformal field theory. At zero\ntemperature the critical line turns into a first-order transition. The fate of\nthis kind of transition in the finite temperature case is discussed.",
        "positive": "Exact duality and local dynamics in SU(N) lattice gauge theory: We construct exact duality transformations in pure SU(N) Hamiltonian lattice\ngauge theory in (2+1) dimension. This duality is obtained by making a series of\niterative canonical transformations on the SU(N) electric vector fields and\ntheir conjugate magnetic vector potentials on the four links around every\nplaquette. The resulting dual description is in terms of the magnetic scalar\nfields or plaquette flux loops and their conjugate electric scalar potentials.\nUnder SU(N) gauge transformations they both transform like adjoint matter\nfields. The dual Hamiltonian describes the nonlocal self-interactions of these\nplaquette flux loops in terms of the electric scalar potentials and with\ninverted coupling. We show that these nonlocal loop interactions can be made\nlocal and converted into minimal couplings by introducing SU(N) auxiliary gauge\nfields along with new plaquette constraints. The matter fields can be included\nthrough minimal coupling. The techniques can be easily generalized to (3+1)\ndimensions."
    },
    {
        "anchor": "Lattice calculation of the $D_{s}$ meson radiative form factors over the\n  full kinematical range: We compute the structure-dependent axial and vector form factors for the\nradiative leptonic decays $D_s\\to \\ell\\nu_\\ell\\gamma$, where $\\ell$ is a\ncharged lepton, as functions of the energy of the photon in the rest frame of\nthe $D_s$ meson. The computation is performed using gauge-field configurations\nwith 2+1+1 sea-quark flavours generated by the European Twisted Mass\nCollaboration and the results have been extrapolated to the continuum limit.\nFor the vector form factor we observe a very significant partial cancellation\nbetween the contributions from the emission of the photon from the strange\nquark and that from the charm quark. The results for the form factors are used\nto test the reliability of various Anz\\\"atze based on single-pole dominance and\nits extensions, and we present a simple parametrization of the form factors\nwhich fits our data very well and which can be used in future phenomenological\nanalyses. Using the form factors we compute the differential decay rate and the\nbranching ratio for the process $D_s\\to e\\nu_e\\gamma$ as a function of the\nlower cut-off on the photon energy. With a cut-off of 10 MeV for example, we\nfind a branching ratio of Br$(E_\\gamma>10\\,\\mathrm{MeV})=4.4(3)\\times 10^{-6}$\nwhich, unlike some model calculations, is consistent with the upper bound from\nthe BESIII experiment Br$(E_\\gamma>10\\,\\mathrm{MeV})<1.3\\times 10^{-4}$ at 90%\nconfidence level. Even for photon energies as low as 10 MeV, the decay $D_s\\to\ne\\nu_e\\gamma$ is dominated by the structure-dependent contribution to the\namplitude (unlike the decays with $\\ell=\\mu$ or $\\tau$), confirming its value\nin searches for hypothetical new physics as well as in determining the\nCabibbo-Kobayashi-Maskawa (CKM) parameters at $O(\\alpha_\\mathrm{em})$, where\n$\\alpha_{\\mathrm{em}}$ is the fine-structure constant.",
        "positive": "Neutron electric dipole moment on the lattice: We carry out a feasibility study toward a lattice QCD calculation of the\nneutron electric dipole moment (NEDM) in the presence of the $\\theta$ term\nusing two different approaches. In the first method, we calculate the CP-odd\nelectromagnetic form factor $F_3$, which becomes the NEDM in the zero momentum\ntransfer limit. At the first order in $\\theta$, we derive a formula connecting\nthe lattice three-point function to the CP-odd electromagnetic form factor. In\nthe second method we directly extract the NEDM from the energy difference\nbetween spin-up and spin-down neutron states in the presence of a constant\nelectric field, without expanding a small but non-zero $\\theta$. We test both\napproaches numerically, employing the domain-wall quark action with the RG\nimproved gauge action in quenched QCD at $a^{-1}\\simeq 2$ GeV on a $16^3\\times\n32\\times 16$ lattice, and further applying the second method to the clover\nquark action at a similar lattice spacing and nucleon mass. We obtain good\nsignals from both approaches. In particular the second method works well with\nboth fermion formulations."
    },
    {
        "anchor": "Quasi parton distributions and the gradient flow: We propose a new approach to determining quasi parton distribution functions\n(PDFs) from lattice quantum chromodynamics. By incorporating the gradient flow,\nthis method guarantees that the lattice quasi PDFs are finite in the continuum\nlimit and evades the thorny, and as yet unresolved, issue of the\nrenormalization of quasi PDFs on the lattice. In the limit that the flow time\nis much smaller than the length scale set by the nucleon momentum, the moments\nof the smeared quasi PDF are proportional to those of the light-front PDF. We\nuse this relation to derive evolution equations for the matching kernel that\nrelates the smeared quasi PDF and the light-front PDF. As part of this\ndiscussion, we elucidate the relationship between the quasi and light-front\nPDFs.",
        "positive": "Scaling property of domain-wall QCD in perturbation theory: We estimate the lattice artifacts in loop correction perturbatively for\ndomain-wall QCD with infinite number of extra flavors. We find that there\nappear no ${\\cal O}(a)$ errors in renormalization factors of quark wave\nfunction, mass and quark bilinear operators at one and two loop level with\noff-shell quark momentum. Our proof is based on even or oddness of the quantum\ncorrection in terms of the quark external momentum and mass, and it can be\nextended to any loop level."
    },
    {
        "anchor": "Introduction to transverse lattice gauge theory: I review a new treatment of an old idea for light-front quantization of\nlattice gauge theories and give new results from some illustrative\ncalculations: [I] transverse lattice gauge theory; [II] pure glue; [III] heavy\nsources and winding modes; [IV] an example -- large-N QCD in 2+1 dimensions.",
        "positive": "Non-Local effective SU(2) Polyakov-loop models from inverse Monte-Carlo\n  methods: The strong-coupling expansion of the lattice gauge action leads to\nPolyakov-loop models that effectively describe gluodynamics at low\ntemperatures, and together with the hopping expansion of the fermion\ndeterminant provides insight into the QCD phase diagram at finite density and\nlow temperatures, although for rather heavy quarks. At higher temperatures the\nstrong-coupling expansion breaks down and it is expected that the interactions\nbetween Polyakov loops become non-local. Here, we therefore test how well pure\nSU(2) gluodynamics can be mapped onto different non-local Polyakov models with\ninverse Monte-Carlo methods. We take into account Polyakov loops in higher\nrepresentations and gradually add interaction terms at larger distances. We are\nparticularly interested in extrapolating the range of non-local terms in\nsufficiently large volumes and higher representations. We study the\ncharacteristic fall-off in strength of the non-local couplings with the\ninteraction distance, and its dependence on the gauge coupling in order to\ncompare our results to existing proposals for non-local effective actions."
    },
    {
        "anchor": "$I=0$ $\u03c0\u03c0$ $s$-wave scattering length from lattice QCD: We deliver lattice results for the $I=0$ $\\pi\\pi$ elastic $s$-wave scattering\nlength calculated with the MILC $N_f=3$ flavors of the Asqtad-improved\nstaggered fermions. The scattering phase shifts are determined by L\\\"uscher's\nformula from the energy-eigenvalues of $\\pi\\pi$ systems at one center of mass\nframe and four moving frames using the moving wall source technique. Our\nmeasurements are good enough to resolve the scattering length $a$ and effective\nrange $r$, moreover, it allows us to roughly estimate the shape parameter $P$.\nUsing our lattice results, the scattering length $a$ and effective range $r$ at\nthe physical point are extrapolated by chiral perturbation theory. Our results\nare reasonably consistent with the Roy equation determinations and the newer\nexperimental data. Numerical computations are carried out with two MILC fine\n($a\\approx0.09$~fm, $L^3 \\times T = 40^3\\times 96$) and one MILC superfine\n($a\\approx0.06$~fm, $L^3 \\times T = 48^3\\times 144$) lattice ensembles at three\npion masses of $m_\\pi\\sim247~{\\rm MeV}$, $249~{\\rm MeV}$, and $314~{\\rm MeV}$,\nrespectively.",
        "positive": "Quark mass dependence of quarkonium properties at finite temperature: Quarkonium properties at finite temperature have been studied with quark\nmasses of the charm and bottom quarks. Our simulations have been performed in\nquenched QCD with the $O(a)$-improved Wilson quarks on large and fine isotropic\nlattices with the spatial lattice extents $N_\\sigma =$ 96, 192 and the\ncorresponding lattice spacings $a =$ 0.0190, 0.00967 fm, respectively, at\ntemperatures in a range between about 0.7$T_c$ and 1.4$T_c$. We show\ntemperature and quark mass dependence of quarkonium correlation functions and\nrelated physical quantities: the quark number susceptibility and the heavy\nquark diffusion constant."
    },
    {
        "anchor": "Color screening in (2+1)-flavor QCD: We study correlation functions of spatially separated static quark-antiquark\npairs in (2+1)-flavor QCD in order to investigate onset and nature of color\nscreening at high temperatures. We perform lattice calculations in a wide\ntemperature range, $140 \\le T \\le 5814\\,{\\rm MeV}$, using the highly improved\nstaggered quark action and several lattice spacings to control discretization\neffects. By comparing at high temperatures our lattice results to weak-coupling\ncalculations as well as to the zero temperature result for the energy of a\nstatic quark-antiquark pair, we observe that color screening sets in at $rT\n\\approx 0.3$. Furthermore, we also observe that in the range $0.3 \\lesssim r T\n\\lesssim 0.6$ weak-coupling calculations in the framework of suitable effective\nfield theories provide an adequate picture of color screening.",
        "positive": "Relativistic, model-independent determination of electromagnetic\n  finite-size effects beyond the point-like approximation: We present a relativistic and model-independent method to derive\nstructure-dependent electromagnetic finite-size effects. This is a systematic\nprocedure, particularly well-suited for automatization, which works at\narbitrarily high orders in the large-volume expansion. Structure-dependent\ncoefficients appear as zero-momentum derivatives of physical form factors which\ncan be obtained through experimental measurements or auxiliary lattice\ncalculations. As an application we derive the electromagnetic finite-size\neffects on the pseudoscalar meson mass and leptonic decay amplitude, through\norders $\\mathcal{O}(1/L^3)$ and $\\mathcal{O}(1/L^2)$, respectively. The\nstructure dependence appears at this order through the meson charge radius and\nthe real radiative leptonic amplitude, which are known experimentally."
    },
    {
        "anchor": "Octet Baryon Magnetic Moments from Lattice QCD: Approaching Experiment\n  from a Three-Flavor Symmetric Point: Lattice QCD calculations with background magnetic fields are used to\ndetermine the magnetic moments of the octet baryons. Computations are performed\nat the physical value of the strange quark mass, and two values of the light\nquark mass, one corresponding to the three-flavor symmetric point, where the\npion mass is 800 MeV, and the other corresponding to a pion mass of 450 MeV.\nThe moments are found to exhibit only mild pion-mass dependence when expressed\nin terms of appropriately chosen magneton units- the natural baryon magneton. A\ncurious pattern is revealed among the anomalous baryon magnetic moments which\nis linked to the constituent quark model, however, careful scrutiny exposes\nadditional features. Relations expected to hold in the large-Nc limit of QCD\nare studied; and, in one case, a clear preference for the quark model over the\nlarge-Nc prediction is found. The magnetically coupled Lambda-Sigma system is\ntreated in detail at the three-flavor symmetric point, with the lattice QCD\nresults comparing favorably with predictions based on SU(3)F symmetry. This\nanalysis enables the first extraction of the isovector transition magnetic\npolarizability. The possibility that large magnetic fields stabilize strange\nmatter is explored, but such a scenario is found to be unlikely.",
        "positive": "Short Strings and New Physics Perspectives in QCD: Within the (dual) Abelian Higgs model, confining strings do not disappear at\nsmall distances but rather become short strings. In compact 3D electrodynamics,\nas we argue here, the confining strings are also manifested at small distances\nin unusual power corrections, disobeying the standard rules of the Operator\nProduct expansion. In the most interesting case of QCD, there is yet no\nderivation of short strings and we turn to phenomenology to find evidence pro\nor contra their existence. The short strings in QCD lead to non-standard power\ncorrections. A tentative conclusion of the analysis of existing data, both in\nnumerical simulations and in real experiments, is that the novel power\ncorrections are present, at least at the mass scale of 1-2 GeV."
    },
    {
        "anchor": "A new technique for solving the freezing problem in the complex Langevin\n  simulation of 4D SU(2) gauge theory with a theta term: We apply the complex Langevin method (CLM) to overcome the sign problem in 4D\nSU(2) gauge theory with a theta term extending our previous work on the 2D U(1)\ncase. The topology freezing problem can be solved by using open boundary\nconditions in all spatial directions, and the criterion for justifying the CLM\nis satisfied even for large $\\theta$ as far as the lattice spacing is\nsufficiently small. However, we find that the CP symmetry at $\\theta=\\pi$\nremains to be broken explicitly even in the continuum and infinite-volume\nlimits due to the chosen boundary conditions. In particular, this prevents us\nfrom investigating the interesting phase structures suggested by the 't Hooft\nanomaly matching condition. We also try the so-called subvolume method, which\nturns out to have a similar problem. We therefore discuss a new technique\nwithin the CLM, which enables us to circumvent the topology freezing problem\nwithout changing the boundary conditions.",
        "positive": "Lattice QCD ensembles with four flavors of highly improved staggered\n  quarks: We present results from our simulations of quantum chromodynamics (QCD) with\nfour flavors of quarks: u, d, s, and c. These simulations are performed with a\none-loop Symanzik improved gauge action, and the highly improved staggered\nquark (HISQ) action. We are generating gauge configurations with four values of\nthe lattice spacing ranging from 0.06 fm to 0.15 fm, and three values of the\nlight quark mass, including the value for which the Goldstone pion mass is\nequal to the physical pion mass. We discuss simulation algorithms, scale\nsetting, taste symmetry breaking, and the autocorrelations of various\nquantities. We also present results for the topological susceptibility which\ndemonstrate the improvement of the HISQ configurations relative to those\ngenerated earlier with the asqtad improved staggered action."
    },
    {
        "anchor": "Anatomy of Isolated Monopole in Abelian Projection of SU(2) Lattice\n  Gauge Theory: We study the structure of the isolated static monopoles in the maximal\nAbelian projection of SU(2) lattice gluodynamics. Our estimation of the\nmonopole radius is $ \\approx 0.06 fm$.",
        "positive": "Colorful SU(2) center vortices in the continuum and on the lattice: The spherical vortex as introduced in [Phys. Rev. D77, 014515 (2008)] is\ngeneralized. A continuum form of the spherical vortex is derived and\ninvestigated in detail. The discrepancy between the gluonic lattice topological\ncharge and the index of the lattice Dirac operator described in previous papers\nis identified as a discretization effect. The importance of the investigations\nfor Monte Carlo configurations is discussed."
    },
    {
        "anchor": "Chiral Phase Transition at Strong Coupling in Lattice QCD: We study the chiral phase transition with staggered fermions on the lattice\nat finite temperature in the strong coupling limit. The thermodynamic potential\nis derived in the large $d$ approximation where $d+1$ is the dimension of space\ntime. Our calculation is simpler than the conventional method and leads to a\nsimple physical interpretation for the approximation scheme.",
        "positive": "Kaon semileptonic decays with $N_f=2+1+1$ HISQ fermions and physical\n  light-quark masses: We discuss the reduction of errors in the calculation of the form factor\n$f_+^{K \\pi}(0)$ with HISQ fermions on the $N_f=2+1+1$ MILC configurations from\nincreased statistics on some key ensembles, new data on ensembles with lattice\nspacings down to 0.042 fm and the study of finite-volume effects within\nstaggered ChPT. We also study the implications for the unitarity of the CKM\nmatrix in the first row and for current tensions with leptonic determinations\nof $\\vert V_{us}\\vert$."
    },
    {
        "anchor": "The two-dimensional O(3) model at nonzero density: from dual lattice\n  simulations to repulsive bosons: We discuss the thermodynamics of the O(3) nonlinear sigma model in 1+1\ndimensions at nonzero chemical potential (equivalent to a magnetic field). In\nits conventional field theory representation the model suffers from a sign\nproblem. By dualizing the lattice model we present, for the first time, nonzero\ndensity data of an asymptotically free theory with dynamical mass-gap. We find\na quantum phase transition at zero temperature where as a function of the\nchemical potential the density assumes a nonzero value. We present evidence for\na corresponding dynamical critical exponent z close to 2. The low energy O(3)\nmodel is conjectured to be described by a massive boson triplet with repulsive\ninteractions. We confirm the universal square root behavior expected for such a\nsystem at low density (and temperature) and compare our data to the results of\nBethe ansatz solutions of the relativistic and non-relativistic one-dimensional\nBose gas. We also comment on a potential Berezinskii-Kosterlitz-Thouless\ntransition at nonzero density.",
        "positive": "Further Precise Determinations of $\u03b1_s$ from Lattice QCD: We present a new determination of the strong coupling constant from lattice\nQCD simulations. We use four different short-distance quantities to obtain the\ncoupling, three different (infrared) meson splittings to tune the simulation\nparameters, and a wide range of lattice spacings, quark masses, and lattice\nvolumes to test for systematic errors. Our final result consists of ten\ndifferent determinations of $\\alpha^{(3)}_{P}(8.2 GeV)$, which agree well with\neach other and with our previous results. The most accurate of these, when\nevolved perturbatively to the $Z^0$ mass, gives $\\alpha^{(5)}_{\\msbar}(M_Z) =\n.1174(24)$. We compare our results with those obtained from other recent\nlattice simulations."
    },
    {
        "anchor": "From Loops to Surfaces: The generating function for all antisymmetric characters of a Wilson loop\nmatrix in SU(N) Yang Mills theory is the partition function of a fermion living\non the curve describing the loop. This generalizes to fermion subsystems living\non higher dimensional submanifolds, for example, surfaces. This write-up also\ncontains some extra background, in response to some questions raised during the\noral presentation.",
        "positive": "Fundamental Composite Higgs Dynamics on the Lattice: SU(2) with Two\n  Flavors: In reference [1] a unified description, both at the effective and fundamental\nLagrangian level, of models of composite Higgs dynamics was proposed. In the\nunified framework the Higgs itself can emerge, depending on the way the\nelectroweak symmetry is embedded, either as a pseudo-Goldstone boson or as a\nmassive excitation of the condensate. The most minimal fundamental description\nconsists of an SU(2) gauge theory with two Dirac fermions transforming\naccording to the defining representation of the gauge group. We therefore\nprovide first principle lattice results for the massive spectrum of this\ntheory. We confirm the chiral symmetry breaking phenomenon and determine the\nlightest spin-one axial and vector masses. The knowledge of the energy scale at\nwhich new states will appear at the Large Hadron Collider is of the utmost\nrelevance to guide experimental searches of new physics."
    },
    {
        "anchor": "Can Lorentz-breaking fermionic condensates form in large N\n  strongly-coupled Lattice Gauge Theories?: The possibility of Lorentz symmetry breaking (LSB) has attracted considerable\nattention in recent years for a variety of reasons, including the attractive\nprospect of the graviton as a Goldstone boson. Though a number of effective\nfield theory analyses of such phenomena have recently been given it remains an\nopen question whether they can take place in an underlying UV complete theory.\nHere we consider the question of LSB in large N lattice gauge theories in the\nstrong coupling limit. We apply techniques that have previously been used to\ncorrectly predict the formation of chiral symmetry breaking condensates in this\nlimit. Generalizing such methods to other composite operators we find that\ncertain LSB condensates can indeed form. In addition, the interesting\npossibility arises of condensates that 'lock' internal with external\nsymmetries.",
        "positive": "Vortex fermion on the lattice: The domain wall fermion formalism in lattice gauge theory is much\ninvestigated recently. This is set up by reducing 4+1 dimensional theory to low\nenergy effective 4 dimensional one. In order to look around other possibilities\nof realizing chiral fermion on the lattice, we construct vortex fermion by\nreducing 4+2 dimensional theory to low energy effective 4 dimensional one on\nthe lattice. In extra 2 dimensions we propose a new lattice regularization\nwhich has a discrete rotational invariance but not a translational one. In\norder to eliminate doubling species in the naive construction we introduce the\nextended Wilson term which is appropriate to our model. We propose two models\nfor convenience and show that a normalizable zero mode solution appears at the\ncore of the vortex."
    },
    {
        "anchor": "Moments of generalized parton distributions and quark angular momentum\n  of the nucleon: The internal structure of hadrons is important for a variety of topics,\nincluding the hadron form factors, proton spin and spin asymmetry in polarized\nproton scattering.\n  For a systematic study generalized parton distributions (GPDs) encode\nimportant information on hadron structure in the entire impact parameter space.\nWe report on a computation of nucleon GPDs based on simulations with two\ndynamical non-perturbatively improved Wilson quarks with pion masses down to\n350MeV. We present results for the total angular momentum of quarks with chiral\nextrapolation based on covariant baryon chiral perturbation theory.",
        "positive": "D*-->Dpi and D*-->Dgamma decays: Axial coupling and Magnetic moment of\n  D* meson: The axial coupling and the magnetic moment of D*-meson or, more specifically,\nthe couplings g(D*Dpi) and g(D*Dgamma), encode the non-perturbative QCD effects\ndescribing the decays D*-->Dpi and D*-->Dgamma. We compute these quantities by\nmeans of lattice QCD with Nf=2 dynamical quarks, by employing the Wilson\n(\"clover\") action. On our finer lattice (a=0.065 fm) we obtain: g(D*Dpi)=20 +/-\n2, and g(D0*D0gamma)=[2.0 +/- 0.6]/GeV. This is the first determination of\ng(D0*D0gamma) on the lattice. We also provide a short phenomenological\ndiscussion and the comparison of our result with experiment and with the\nresults quoted in the literature."
    },
    {
        "anchor": "Comments on \"Various Super Yang-Mills Theories with Exact Supersymmetry\n  on the Lattice\": We make corrections on the paper by Sugino [{\\it JHEP} {\\bf 0501} (2005)\n016].",
        "positive": "$B_K$ in unquenched QCD using improved staggered fermions: We present preliminary results for $B_K$ calculated using improved staggered\nfermions with a mixed action (HYP-smeared staggered valence quarks and AsqTad\nstaggered sea quarks). We investigate the effect of non-degenerate quarks on\n$B_K$ and attempt to estimate the ${\\cal O}(a^2)$ effect due to non-Goldstone\npions in loops. We fit the data to continuum partially quenched chiral\nperturbation theory. We find that the quality of fit for $B_K$ improves if we\ninclude non-degenerate quark mass combinations. We also observe, however, that\nthe fitting curve deviates from the data points in the light quark mass region.\nThis may indicate the need to include taste-breaking in pion loops."
    },
    {
        "anchor": "Chiral dynamics in the low-temperature phase of QCD: We investigate the low-temperature phase of QCD and the crossover region with\ntwo light flavors of quarks. The chiral expansion around the point $(T,m=0)$ in\nthe temperature vs. quark-mass plane indicates that a sharp real-time\nexcitation exists with the quantum numbers of the pion. An exact sum rule is\nderived for the thermal modification of the spectral function associated with\nthe axial charge density; the (dominant) pion pole contribution obeys the sum\nrule. We determine the two parameters of the pion dispersion relation using\nlattice QCD simulations and test the applicability of the chiral expansion. The\ntime-dependent correlators are also analyzed using the Maximum Entropy Method,\nyielding consistent results. Finally, we test the predictions of the chiral\nexpansion around the point $(T=0,m=0)$ for the temperature dependence of static\nobservables.",
        "positive": "Flavour Singlet Mesons in Full QCD on the Lattice: We apply spectral methods to compute the OZI-rule suppressed loop-loop\ncorrelators in the pseudoscalar meson flavour singlet channel. Using SESAM\nconfigurations (obtained with two degenerate sea quark flavours on 16x16x16x32\nlattices at beta = 5.6 with standard Wilson action), we find for the first time\nclear evidence for mass plateau formation in the eta' channel of this theory.\nAs a consequence, we observe a clear signal of a mass gap persistent under\nchiral extrapolation. This sets the stage for a more realistic two-channel\napproach, where partially quenched strange quarks would be included, in\naddition to u, d sea quarks."
    },
    {
        "anchor": "Oscillatory behavior of the domain wall fermions revisited: In the generic domain wall fermion formulation of chiral fermions on the\nlattice, the zero modes of the four-dimensional Wilson fermion operator with\nthe negative mass parameter $-M_5$ introduce unphysical massive modes\npropagating in the four-dimensional spacetime. In the free fermion case, the\npole mass of this kind of unphysical modes is given by $\\tilde{E}=\\ln(1-M_5)$,\nwhich acquires an imaginary part, $i\\pi$, when $M_5>1$ and results in an\noscillatory behavior of the domain wall fermion propagator in time. The\nexistence of the unphysical modes in the presence of gauge fields is\ninvestigated in the mean field approximation, and their physical consequences\nare discussed. In addition, we also give a semiquantitative criterion for\ntuning $M_5$ in the realistic numerical study.",
        "positive": "Universal aspects in the equation of state for Yang-Mills theories: We present high-precision lattice calculations of the thermodynamics of\nYang-Mills theories with different gauge groups. In the confining phase, we\nshow that the equation of state is described remarkably well by a gas of\nmassive, non-interacting glueballs, provided that an effective bosonic\nclosed-string model is used to derive an exponentially growing Hagedorn\nspectrum for the heavy states. In particular, this model describes very\naccurately the results for the SU(3) theory reported by Bors\\'anyi et al. in\nJHEP 07 (2012) 056, as well as a novel set of lattice data for the SU(2)\ntheory. In addition, we also also show that the equation of state in the\ndeconfined phase exhibits a near perfect proportionality to the number of gluon\ndegrees of freedom, including for the Yang-Mills theory based on the\nexceptional, center-less gauge group $G_2$."
    },
    {
        "anchor": "Lattice QCD with Exponentially Small Chirality Breaking: A new multifermion formulation of lattice QCD is proposed. The model is free\nof spectrum doubling and preserves all nonanomalous chiral symmetries up to\nexponentially small corrections. It is argued that a small number of fermion\nfields may provide a good approximation making computer simulations feasible.",
        "positive": "Matrix product variational formulation for lattice gauge theory: For hamiltonian lattice gauge theory, we introduce the matrix product anzats\ninspired from density matrix renormalization group. In this method,\nwavefunction of the target state is assumed to be a product of finite matrices.\nAs a result, the energy becomes a simple function of the matrices, which can be\nevaluated using a computer. The minimum of the energy function corresponds to\nthe vacuum state. We show that the S=1/2 Heisenberg chain model are well\ndescribed with the ansatz. The method is also applied to the two-dimensional\nS=1/2 Heisenberg and U(1) plaquette chain models."
    },
    {
        "anchor": "Walking near a Conformal Fixed Point: the 2-d O(3) Model at theta near\n  pi as a Test Case: Slowly walking technicolor models provide a mechanism for electroweak\nsymmetry breaking whose nonperturbative lattice investigation is rather\nchallenging. Here we demonstrate walking near a conformal fixed point\nconsidering the 2-d lattice O(3) model at vacuum angle $\\theta \\approx \\pi$.\nThe essential features of walking technicolor models are shared by this toy\nmodel and can be accurately investigated by numerical simulations. We show\nresults for the running coupling and the beta-function and we perform a finite\nsize scaling analysis of the massgap close to the conformal point.",
        "positive": "Towards sampling complex actions: Path integrals with complex actions are encountered for many physical systems\nranging from spin- or mass-imbalanced atomic gases and graphene to quantum\nchromo-dynamics at finite density to the non-equilibrium evolution of quantum\nsystems. Many computational approaches have been developed for tackling the\nsign problem emerging for complex actions. Among these, complex Langevin\ndynamics has the appeal of general applicability. One of its key challenges is\nthe potential convergence of the dynamics to unphysical fixed points. The\nstatistical sampling process at such a fixed point is not based on the physical\naction and hence leads to wrong predictions. Moreover, its unphysical nature is\nhard to detect due to the implicit nature of the process. In the present work\nwe set up a general approach based on a Markov chain Monte Carlo scheme in an\nextended state space. In this approach we derive an explicit real sampling\nprocess for generalized complex Langevin dynamics. Subject to a set of\nconstraints, this sampling process is the physical one. These constraints\noriginate from the detailed-balance equations satisfied by the Monte Carlo\nscheme. This allows us to re-derive complex Langevin dynamics from a new\nperspective and establishes a framework for the explicit construction of new\nsampling schemes for complex actions."
    },
    {
        "anchor": "Griffiths Inequalities for some O(n) Classical Spin Models with $n\\ge 3$: The first and second Griffiths inequalities are proved for some classical\nO($n$)-invariant spin models (including Euclidean quantum field theories) for\nany $n$. The proof assumes a certain condition on an integral transform of the\nmeasure. Some examples are discussed.",
        "positive": "Finite-temperature phase structure of SU(4) gauge theory with multiple\n  fermion representations: We investigate the phase structure of SU(4) gauge theory with the gauge field\nsimultaneously coupled to two flavors of fermion in the fundamental\nrepresentation and two flavors of fermion in the two-index antisymmetric\nrepresentation. We find that the theory has only two phases, a low-temperature\nphase with both species of fermion confined and chirally broken, and a\nhigh-temperature phase with both species of fermion deconfined and chirally\nrestored. The single phase transition in the theory appears to be first order,\nin agreement with theoretical predictions."
    },
    {
        "anchor": "Infrared behavior and infinite-volume limit of gluon and ghost\n  propagators in Yang-Mills theories: Lattice studies of the infrared behavior of gluon and ghost propagators are a\nkey probe of confinement scenarios in Yang-Mills theories. However,\nfinite-volume effects become an important issue as the infrared limit is\napproached. By considering general quantities -- namely an associated\nsusceptibility in the gluon case and properties of the lowest-lying eigenmode\nof the Faddeev-Popov matrix in the ghost case -- one can derive rigorous upper\nand lower bounds for the propagators. The bounds allow a better control over\nthe extrapolation of lattice results to the infinite-volume limit. In the case\nof the gluon propagator, an intuitive statistical argument suggests a precise\nvolume dependence for the bounds. This dependence is nicely confirmed by the\nlattice data, leading to a finite gluon propagator at zero momentum. At the\nsame time, an enhancement of the ghost propagator in the infrared limit seems\nunlikely. Our analysis is applied to the case of Landau gauge and SU(2) gauge\ngroup, using the largest lattice sizes to date.",
        "positive": "Equation of state of a hot-and-dense quark gluon plasma: lattice\n  simulations at real $\u03bc_B$ vs. extrapolations: The equation of state of the quark gluon plasma is a key ingredient of heavy\nion phenomenology. In addition to the traditional Taylor method, several novel\napproximation schemes have been proposed with the aim of calculating it at\nfinite baryon density. In order to gain a pragmatic understanding of the limits\nof these schemes, we compare them to direct results at $\\mu_B>0$, using\nreweighting techniques free from an overlap problem. We use 2stout improved\nstaggered fermions with 8 time-slices and cover the entire RHIC BES range in\nthe baryochemical potential, up to $\\mu_B/T=3$."
    },
    {
        "anchor": "Evidence of effective axial U(1) symmetry restoration at high\n  temperature QCD: We study the axial U(1) symmetry at finite temperature in two-flavor lattice\nQCD. Employing the Mobius domain-wall fermions, we generate gauge\nconfigurations slightly above the critical temperature Tc with different\nlattice sizes L = 2-4 fm. Our action allows frequent topology tunneling while\nkeeping good chiral symmetry close enough to that of overlap fermions. This\nallows us to recover full chiral symmetry by an overlap/domain-wall\nreweighting. Above the phase transition, a strong suppression of the low-lying\nmodes is observed in both of overlap and domain-wall Dirac spectra. We,\nhowever, find a sizable violation of the Ginsparg-Wilson relation in the Mobius\ndomain-wall Dirac eigenmodes, which dominates the signals of the axial U(1)\nsymmetry breaking near the chiral limit. We also find that the use of overlap\nfermion only in the valence sector is dangerous since it suffers from the\nartifacts due to partial quenching. Reweighting the Mobius domain-wall fermion\ndeterminant to that of the overlap fermion, we observe the axial U(1) breaking\nto vanish in the chiral limit, which is stable against the changes of the\nlattice volume and lattice spacing.",
        "positive": "Running coupling constant and mass anomalous dimension of six-flavor\n  SU(2) gauge theory: In the exploration of viable models of dynamical electroweak symmetry\nbreaking, it is essential to locate the lower end of the conformal window and\nknow the mass anomalous dimensions there for a variety of gauge theories. We\ncalculate, with the Schr\\\"odinger functional scheme, the running coupling\nconstant and the mass anomalous dimension of SU(2) gauge theory with six\nmassless Dirac fermions in the fundamental representation. The calculations are\nperformed on $6^4$ - $24^4$ lattices over a wide range of lattice bare\ncouplings to take the continuum limit. The discretization errors for both\nquantities are removed perturbatively. We find that the running slows down and\ncomes to a stop at $0.06 \\lesssim 1/g^2 \\lesssim 0.15$ where the mass anomalous\ndimension is estimated to be $0.26 \\lesssim \\gamma^*_m \\lesssim 0.74$."
    },
    {
        "anchor": "Charm quark mass using a massive nonperturbative renormalisation scheme: We present a first numerical implementation of a massive nonperturbative\nrenormalisation scheme, RI/mSMOM, in the study of heavy quarks using the\ndomain-wall fermion action. In particular, we calculate renormalisation\nconstants for fermion bilinears at non-vanishing heavy-quark masses and compare\nthe approach to the continuum of the renormalised charm-quark mass with that\nfrom a mass-independent scheme.",
        "positive": "Quark antiquark energies and the screening mass in a Quark-Gluon plasma\n  at low and high temperatures: We discuss quark antiquark energies and the screening mass in hot QCD using\nthe non-perturbative lattice approach. For this purpose we analyze properties\nof quark antiquark energies and entropies at infinitely large separation of the\nquark antiquark pair at low and high temperatures. In the limit of high\ntemperatures these energies and entropies can be related perturbatively to the\ntemperature dependence of the Debye mass and the coupling. On the one hand our\nanalysis thus suggests that the quark antiquark energies at (infinite) large\ndistances are rather related to the Debye screening mass and the coupling than\nto the temperature dependence of heavy-light meson masses. On the other hand we\nfind no or only little differences in all mass scales introduced by us when\nchanging from quenched to 2-flavor QCD at temperatures which are only\nmoderately above the phase transition."
    },
    {
        "anchor": "The phase diagram of QCD with two and four flavors: results with HYP\n  fermions: We study the finite temperature phase transition of four and two flavor\nstaggered fermions with hypercubic smeared link actions. These preliminary\nstudies suggest that the improved flavor symmetry of the fermionic action can\nhave a significant effect on the finite temperature phase diagram.",
        "positive": "Spontaneous symmetry breaking on the lattice generated by Yukawa\n  interaction: We study by numerical simulation a lattice Yukawa model with naive fermions\nat intermediate values of the Yukawa coupling $y$ when the nearest neighbour\ncoupling $\\kp$ of the scalar field $\\Phi$ is very weakly ferromagnetic ($\\kp\n\\approx 0$) or even antiferromagnetic ($\\kappa < 0$) and the nonvanishing value\nof $\\vev$ is generated by the Yukawa interaction. The renormalized Yukawa\ncoupling $y_R$ achieves here its maximal value and this $y$-region is thus of\nparticular importance for lattice investigations of strong Yukawa interaction.\nHowever, here the scalar field propagators have a very complex structure caused\nby fermion loop corrections and by the proximity of phases with\nantiferromagnetic properties. We develop methods for analyzing these\npropagators and for extracting the physical observables. We find that going\ninto the negative $\\kp$ region, the scalar field renormalization constant\nbecomes small and $y_R$ does not seem to exceed the unitarity bound, making the\nexistence of a nontrivial fixed point in the investigated Yukawa model quite\nunlikely."
    },
    {
        "anchor": "A lattice implementation of the eta-invariant and effective action for\n  chiral fermions on the lattice: We consider a lattice implementation of the eta-invariant, using the complex\nphase of the determinant of the simplified domain-wall fermion, which couples\nto an interpolating five-dimensional gauge field. We clarify the relation to\nthe effective action for chiral Ginsparg-Wilson fermions. The integrability,\nwhich holds true for anomaly-free theories in the classical continuum limit, is\nnot assured on the lattice with a finite spacing. A lattice expression for the\nfive-dimensional Chern-Simons term is obtained.",
        "positive": "Lattice Landau gauge quark propagator and the quark-gluon vertex: We report preliminary results of our ongoing lattice computation of the\nLandau gauge quark propagator and the soft gluon limit of the quark-gluon\nvertex with 2 flavors of dynamical O(a) improved Wilson fermions."
    },
    {
        "anchor": "Gribov Copies and Gauge Fixing in Lattice Gauge Theories: We address the problem of the gauge fixing versus Gribov copies in lattice\ngauge theories. For the Landau gauge, results show that a suitable combination\nof evolutionary algorithms with traditional steepest descent methods identifies\nthe global maximum of the optimisation function. We discuss the performance of\nthe combined algorithm on small cubic lattices for SU(2) and SU(3).",
        "positive": "Exploring S-Wave Threshold Effects in QCD: A Heavy-Light Approach: QCD exhibits complex dynamics near S-wave two-body thresholds. For light\nmesons, we see this in the failure of quark models to explain the $f_0(500)$\nand $K_0^*(700)$ masses. For charmonium, an unexpected $X(3872)$ state appears\nat the open charm threshold. In heavy-light systems, analogous threshold\neffects appear for the lowest $J^P = 0^+$ and $1^+$ states in the $D_s$ and\n$B_s$ systems. Here we describe how lattice QCD can be used to understand these\nthreshold dynamics by smoothly varying the strange-quark mass when studying the\nheavy-light systems. Small perturbations around the physical strange quark mass\nare used so to always remain near the physical QCD dynamics. This calculation\nis a straightforward extension of those already in the literature and can be\nundertaken by multiple lattice QCD collaborations with minimal computational\ncost."
    },
    {
        "anchor": "Measurement of the penetration depth and coherence length in U(1) and\n  SU(2) dual Abrikosov vortices: We calculate the electric field and the curl of the magnetic monopole current\nfor U(1) and for SU(2) in the maximal abelian gauge in the mid- plane between a\nquark antiquark pair. The results can be understood as a dual Abrikosov vortex\nin the Ginzburg-Landau theory.",
        "positive": "The closed string spectrum of SU(N) gauge theories in 2+1 dimensions: We use lattice techniques to study the closed-string spectrum of SU(N) gauge\ntheories in 2+1 dimensions. We calculate the energies of the lowest lying ~30\nstates for strings with lengths between l ~ 0.45 fm and l ~ 3 fm, and compare\nto different theoretical predictions. We obtain unambiguous evidence that the\nclosed-strings are in the universality class of the Nambu-Goto free bosonic\nstring. Moreover, we clearly see that our data can be described by a covariant\nstring theory with a small/moderate correction down to very short distance\nscales, and possibly on all distance scales at large-N."
    },
    {
        "anchor": "Quark Flavor Physics Review: I review the status of lattice-QCD calculations relevant to quark flavor\nphysics. The recent availability of physical-mass ensembles with large physical\nvolumes generated by a growing number of lattice collaborations is an exciting\ndevelopment and I discuss their impact on the landscape of lattice flavor\nphysics calculations. The activities of the newly formed FLAG-2 collaboration\nwhich provides averages of quantities calculated in lattice QCD that are\nrelevant for quark flavor physics are also discussed. My talk covers (a subset\nof) the same quantities reviewed by FLAG-2, including results for $K$,\n$D_{(s)}$, and $B_{(s)}$ meson decay constants and semileptonic decay form\nfactors, as well as for hadronic matrix elements of neutral ($K$, $D$, and\n$B_{(s)}$) meson mixing. I also briefly discuss recent progress towards\nunderstanding nonleptonic $K$ decay and long-distance contributions to $\\Delta\nm_K$.",
        "positive": "Color halo scenario of charmonium-like hybrids: The internal structures of $J^{PC}=1^{--}, (0,1,2)^{-+}$ charmonium-like\nhybrids are investigated under lattice QCD in the quenched approximation. We\ndefine the Bethe-Salpeter wave function $\\Phi_n(r)$ in the Coulomb gauge as the\nmatrix element of a spatially extended hybrid-like operator $\\bar{c}{c}g$\nbetween the vacuum and $n$-th state for each $J^{PC}$ with $r$ being the\nspatial separation between a localized $\\bar{c}c$ component and the\nchromomagnetic strength tensor. These wave functions exhibit some similarities\nfor states with the aforementioned different quantum numbers, and their\n$r$-behaviors (no node for the ground states and one node for the first excited\nstates) imply that $r$ can be a meaningful dynamical variable for these states.\nAdditionally, the mass splittings of the ground states and first excited states\nof charmonium-like hybrids in these channels are obtained for the first time to\nbe approximately 1.2-1.4 GeV. These results do not support the flux-tube\ndescription of heavy-quarkonium-like hybrids in the Born-Oppenheimer\napproximation. In contrast, a charmonium-like hybrid can be viewed as a \"color\nhalo\" charmonium for which a relatively localized color octet $\\bar{c}c$ is\nsurrounded by gluonic degrees of freedom, which can readily decay into a\ncharmonium state along with one or more light hadrons. The color halo picture\nis compatible with the decay properties of $Y(4260)$ and suggests LHCb and\nBelleII to search for $(0,1,2)^{-+}$ charmonium-like hybrids in\n$\\chi_{c0,1,2}\\eta$ and $J/\\psi \\omega (\\phi)$ final states."
    },
    {
        "anchor": "More about exactly massless quarks on the lattice: In a previous publication [hep-lat/9707022] I showed that the fermion\ndeterminant for strictly massless quarks can be written on the lattice as $\\det\nD$, where $D$ is a certain finite square matrix explicitly constructed from the\nlattice gauge fields. Here I show that $D$ obeys the Ginsparg-Wilson relation\n$D\\gamma_5 D = D\\gamma_5 +\\gamma_5 D$.",
        "positive": "Searching for diquarks in hadrons: Since the early days of QCD, it has been argued that inside hadrons quarks\norganise into substructures. Among those, popular pictures of various phenomena\n(including exotica and colour superconductivity) give a prominent role to\ndiquarks, i.e. to colour antitriplet combinations of two quarks. Using a\ngauge-invariant setup, which combines the diquark with a static quark, we study\nspatial correlations of the two light quarks inside the diquark. After\nillustrating the setup, we discuss our first results for both the scalar\n(``good'') and the spin one (``bad'') diquark channels. In a regime in which\n$m_{\\pi} \\simeq 830$ MeV, our data show unambiguously that a scalar diquark\nforms with a size of $\\simeq$ 0.9 fm. For the vector diquark we are able to put\na lower bound of 4.1(7) fm on its size. We also investigate the mass splitting\nbetween the good and the bad diquark; our findings are compatible with\nphenomenologically inspired predictions for this quantity."
    },
    {
        "anchor": "A Preliminary Determination of the Second Mellin Moment of the Pion's\n  Distribution Amplitude Using the Heavy Quark Operator Product Expansion: We explore the feasibility of determining Mellin moments of the pion's light\ncone distribution amplitude using the heavy quark operator product expansion\n(HOPE) method. As the first step of a proof of principle study we pursue a\ndetermination of the second Mellin moment. We discuss our choice of kinematics\nwhich allows us to successfully extract the moment at low pion momentum. We\ndescribe the numerical simulation, and describe the data analysis, which leads\nus to a preliminary determination of the second Mellin moment in the continuum\nlimit in the quenched approximation as $\\langle\\xi^2\\rangle=0.19(7)$ in the\n$\\bar{\\text{MS}}$ scheme at 2 GeV.",
        "positive": "The Scaling of Exact and Approximate Ginsparg-Wilson Fermions: We construct a number of lattice fermions, which fulfill the Ginsparg-Wilson\nrelation either exactly or approximately, and test them in the framework of the\n2-flavor Schwinger model. We start from explicit approximations within a short\nrange, and study this formulation, as well as its correction to an exact\nGinsparg-Wilson fermion by the ``overlap formula''. Then we suggest a new\nmethod to realize this correction perturbatively, without using the tedious\nsquare root operator. In this way we combine many favorable properties: good\nchiral behavior, small mass renormalization, excellent scaling and rotational\ninvariance, as well as a relatively modest computational effort, which makes\nsuch formulations most attractive for QCD."
    },
    {
        "anchor": "The Deconfinement Transition on Coarse Lattices: We compute the critical temperature $T_c$ for the deconfinement transition of\npure QCD on coarse lattices, with $N_t = 2, 3, 4$, and lattice spacings from\n.33 fm to .15 fm. We employ a perturbatively improved gluon action designed to\nremove order $a^2$ and $\\alpha_s a^2$ errors. We find that $T_c$ in units of\nthe charmonium 1P--1S splitting and the torelon mass is independent of $a$ to\nwithin approximately 5\\%.",
        "positive": "Schr\u00f6dinger functional boundary conditions and improvement for N>3: The standard method to calculate non-perturbatively the evolution of the\nrunning coupling of a SU(N) gauge theory is based on the Schr\\\"odinger\nfunctional (SF). In this paper we construct a family of boundary fields for\ngeneral values of N which enter the standard definition of the SF coupling. We\nprovide spatial boundary conditions for fermions in several representations\nwhich reduce the condition number of the squared Dirac operator. In addition,\nwe calculate the O(a) improvement coefficients for N>3 needed to remove\nboundary cutoff effects from the gauge action. After this, residual cutoff\neffects on the step scaling function are shown to be very small even when\nconsidering non-fundamental representations. We also calculate the ratio of\nLambda parameters between the MS-bar and SF schemes."
    },
    {
        "anchor": "Hybrid mesons from quenched QCD: We use lattice methods to evaluate from first principles the spectrum of\nhybrid mesons produced by gluonic excitations in quenched QCD with quark masses\nnear the strange quark mass. For the spin-exotic mesons with $J^{PC}=1^{-+},\\\n0^{+-}$, and $2^{+-}$ which are not present in the quark model, we determine\nthe lightest state to be $1^{-+}$ with mass of 2.0(2) GeV.",
        "positive": "5D Maximally Supersymmetric Yang-Mills on the Lattice: We provide details of the lattice construction of five-dimensional maximally\nsupersymmetric Yang-Mills theory. The lattice theory is supersymmetric, gauge\ninvariant and free from spectrum doublers. Such a supersymmetric lattice\nformulation is interesting as it can be used for non-perturbative explorations\nof the five-dimensional theory, which has a known gravitational dual."
    },
    {
        "anchor": "Novel Algorithms for Computing Correlation Functions of Nuclei: The computational cost required to calculate nuclear correlation functions\ngrows factorially in the number of quarks, making the study of large nuclei\ninaccessible to ab initio study using lattice QCD at the present time. However,\nthe tensor expressions corresponding to many of these correlation functions\nexhibit a high degree of permutation symmetry that can be exploited to reduce\ncomputational work. We present promising speed-ups for certain choices of\ninterpolating operators using two new algorithms for computing nuclear\ncorrelation functions.",
        "positive": "Low-mode deflation for twisted-mass and RHMC reweighting in lattice QCD: We propose improved estimators to compute the reweighting factors which are\nneeded for lattice QCD calculations that rely on twisted-mass reweighting for\nthe light quark contribution and the Rational Hybrid Monte Carlo (RHMC)\nalgorithm for non-degenerate quark masses. This is the case for a number of\nmodern large-scale simulations based on O(a) improved Wilson fermions. We find\na significant reduction of uncertainties for the reweighting factors at similar\ncomputational cost compared to the conventional estimation. This leads to a\nsignificant increase in precision for phenomenologically relevant observables\nwith high correlation to the low eigenmodes of the Wilson-Dirac operator in the\npresence of exceptionally small eigenvalues. Supplementary details regarding\nthe spectral gap of the light quark Dirac operator on the 2+1 flavor\nlarge-volume ensembles explored in this study can be found in an accompanying\nappendix."
    },
    {
        "anchor": "Short Range Operator Contributions to $0\u03bd\u03b2\u03b2$ decay from LQCD: The search for neutrinoless double beta decay of nuclei is believed to be one\nof the most promising means to search for new physics. Observation of this very\nrare nuclear process, which violates Lepton Number conservation, would imply\nthe neutrino sector has a Majorana mass component and may also provide an\nexplanation for the universe matter-antimatter asymmetry of the universe. In\nthe case where a heavy intermediate particle is exchanged in this process, QCD\ncontributions from short range interactions become relevant and the calculation\nof matrix elements with four-quark operators becomes necessary. In these\nproceedings we will discuss our current progress in the calculation of these\nfour-quark operators from LQCD.",
        "positive": "Light Nuclei and Hypernuclei from Quantum Chromodynamics in the Limit of\n  SU(3) Flavor Symmetry: The binding energies of a range of nuclei and hypernuclei with atomic number\nA <= 4 and strangeness |s| <= 2, including the deuteron, di-neutron,\nH-dibaryon, 3He, Lambda 3He, Lambda 4He, and Lambda Lambda 4He, are calculated\nin the limit of flavor-SU(3) symmetry at the physical strange quark mass with\nquantum chromodynamics (without electromagnetic interactions). The nuclear\nstates are extracted from Lattice QCD calculations performed with n_f=3\ndynamical light quarks using an isotropic clover discretization of the\nquark-action in three lattice volumes of spatial extent L ~ 3.4 fm, 4.5 fm and\n6.7 fm, and with a single lattice spacing b ~ 0.145 fm."
    },
    {
        "anchor": "A lattice study of the Faddeev-Niemi effective action: We perform a lattice analysis of the Faddeev-Niemi effective action\nconjectured to describe the low energy sector of SU(2) Yang-Mills theory. We\ngeneralize the effective action such that it contains all operators built from\na unit color vector field n with O(3)-symmetry and maximally four derivatives.\nTo avoid the presence of Goldstone bosons, we include explicit symmetry\nbreaking terms parametrized by an external field h of mass-dimension two. We\nfind a mass gap of the order of 1.5 GeV.",
        "positive": "K \\to \u03c0\u03c0decay amplitudes from the lattice: In order to directly compute physical two-pion K-decay amplitudes using\nlattice methods we must prepare a two-pion state with non-zero relative\nmomentum. Building upon a proposal of Lellouch and L\\\"uscher, we describe a\nfinite-volume method to realize such a state as the lowest energy state of two\npions."
    },
    {
        "anchor": "Temperature dependence of bulk viscosity within lattice simulation of\n  $SU(3)$--gluodynamics: In this paper the temperature dependence of the $SU(3)$--gluodynamics bulk\nviscosity is studied within lattice simulations. To carry out this study we\nmeasure the correlation function of the trace of the energy-momentum tensor for\na set of temperatures within the range $T/T_c \\in (0.9, 1.5)$. To extract the\nbulk viscosity from the correlation function we apply the Backus-Gilbert method\nand the Tikhonov regularization method. We show that the ratio $\\zeta/s$ is\nsmall in the region $T/T_c \\geqslant 1.1-1.2$ and in the vicinity of the\ntransition $T/T_c \\leqslant 1.1-1.2$ it quickly rises. Our results are in\nagreement with previous lattice studies and in a reasonable agreement with\nother phenomenological approaches. Obtained values of the bulk viscosity are\nsignificantly larger than perturbative results, what confirms that QGP is a\nstrongly correlated system.",
        "positive": "Preconditioning of Improved and ``Perfect'' Fermion Actions: We construct a locally-lexicographic SSOR preconditioner to accelerate the\nparallel iterative solution of linear systems of equations for two improved\ndiscretizations of lattice fermions: the Sheikholeslami-Wohlert scheme where a\nnon-constant block-diagonal term is added to the Wilson fermion matrix and\nrenormalization group improved actions which incorporate couplings beyond\nnearest neighbors of the lattice fermion fields. In case (i) we find the block\nllssor-scheme to be more effective by a factor about 2 than odd-even\npreconditioned solvers in terms of convergence rates, at beta=6.0. For type\n(ii) actions, we show that our preconditioner accelerates the iterative\nsolution of a linear system of hypercube fermions by a factor of 3 to 4."
    },
    {
        "anchor": "Hadron Spectrum in a Two-Colour Baryon-Rich Medium: The hadron spectrum of SU(2) lattice gauge theory with two flavours of Wilson\nquark is studied on an 8^3x16 lattice using all-to-all propagators, with\nparticular emphasis on the dependence on quark chemical potential mu. As mu is\nincreased from zero the diquark states with non-zero baryon number B respond as\nexpected, while states with B=0 remain unaffected until the onset of non-zero\nbaryon density at mu=m_pi/2. Post onset the pi-meson mass increases in\naccordance with chiral perturbation theory while the rho becomes lighter. In\nthe diquark sector a Goldstone state associated with a superfluid ground state\ncan be identified. A further consequence of superfluidity is an approximate\ndegeneracy between mesons and baryons with the same spacetime and isospin\nquantum numbers. Finally we find tentative evidence for the binding of states\nwith kaon quantum numbers within the baryonic medium.",
        "positive": "Staggered domain wall fermions: Staggered Domain Wall Fermions (SDWF) combine the attractive chiral\nproperties of staggered fermions with those of domain wall fermions. SDWF\ndescribe four flavors with exact U(1)xU(1) flavor chiral symmetry. An extra\nlattice dimension is introduced and the full SU(4)xSU(4) flavor chiral symmetry\nis recovered as its size is increased. Here, the free theory of SDWF is\ndescribed and a preliminary discussion of the interacting case is presented.\nSDWF may be well suited for numerical simulation of lattice QCD thermodynamics."
    },
    {
        "anchor": "Implementing Hybrid Monte Carlo with stout-smeared chirally improved\n  Dirac operators: We discuss our implementation of dynamical Ginsparg-Wilson type fermions\nusing a stout-smeared chirally improved Dirac operator. Such operators have\nbeen studied extensively in quenched calculations within the\nBern-Graz-Regensburg (BGR) collaboration. Here we discuss the development and\ntesting of the Hybrid Monte Carlo algorithm with this Dirac operator. We study\nthe chiral properties of this operator in a dynamical setup, comparing, e.g.,\nthe spectra of the operator for the dynamical and quenched cases. We then\ndiscuss quantitative features of the algorithm like autocorrelation and\nperformance.",
        "positive": "Scaling analysis of the magnetic monopole mass and condensate in the\n  pure U(1) lattice gauge theory: We observe the power law scaling behavior of the monopole mass and condensate\nin the pure compact U(1) gauge theory with the Villain action. In the Coulomb\nphase the monopole mass scales with the exponent \\nu_m=0.49(4). In the\nconfinement phase the behavior of the monopole condensate is described with\nremarkable accuracy by the exponent \\beta_{exp}=0.197(3). Possible implications\nof these phenomena for a construction of a strongly coupled continuum U(1)\ngauge theory are discussed."
    },
    {
        "anchor": "Explicitly real form of the Wilson-Dirac matrix for SU(2): The Wilson-Dirac matrix for SU(2) with I=1/2 fermions is written in an\nexplicitly real form. The basis change relating it to the conventional form in\nwhich the matrix has complex entries is also given. Some applications are\npresented.",
        "positive": "High Precision determination of the pi, K, D and D_s decay constants\n  from lattice QCD: We determine $D$ and $D_s$ decay constants from lattice QCD with 2% errors, 4\ntimes better than experiment and previous theory: $f_{D_s}$ = 241(3) MeV, $f_D$\n= 207(4) MeV and $f_{D_s}/f_D$ = 1.164(11).\n  We also obtain $f_K/f_{\\pi}$ = 1.189(7) and $(f_{D_s}/f_D)/(f_K/f_{\\pi})$ =\n0.979(11). Combining with experiment gives $V_{us}$=0.2262(14) and\n$V_{cs}/V_{cd}$ of 4.43(41). We use a highly improved quark discretization on\nMILC gluon fields that include realistic sea quarks fixing the $u/d, s$ and $c$\nmasses from the $\\pi$, $K$, and $\\eta_c$ meson masses. This allows a stringent\ntest against experiment for $D$ and $D_s$ masses for the first time (to within\n7 MeV)."
    },
    {
        "anchor": "Inverse Monte-Carlo and Demon Methods for Effective Polyakov Loop Models\n  of SU(N)-YM: We study effective Polyakov loop models for SU(N) Yang-Mills theories at\nfinite temperature. In particular effective models for SU(3) YM with an\nadditional adjoint Polyakov loop potential are considered. The rich phase\nstructure including a center and anti-center directed phase is reproduced with\nan effective model utilizing the inverse Monte-Carlo method. The demon method\nas a possibility to obtain the effective models' couplings is compared to the\nmethod of Schwinger-Dyson equations. Thermalization effects of microcanonical\nand canonical demon method are analyzed. Finally the elaborate canonical demon\nmethod is applied to the finite temperature SU(4) YM phase transition.",
        "positive": "Detecting Dual Superconductivity in the Ground State of Gauge Theories -\n  II: A monopole creation operator is constructed: its vacuum expectation value is\nan order parameter for dual superconductivity in that, if different from zero\nit signals spontaneous breaking of the U(1) symmetry corresponding to monopole\ncharge conservation. The operator is tested on compact U(1) gauge theory on\nlattice. For SU(2) gauge theory it clearly demonstrates that confinement is\nproduced by dual superconductivity."
    },
    {
        "anchor": "Microscopic Encoding of Macroscopic Universality in QCD Chiral Phase\n  Transition: We reveal that the universal scaling properties of the chiral phase\ntransition in quantum chromodynamics (QCD) at the macroscale are, in fact,\nencoded within the microscopic energy levels of its fundamental constituents,\nthe quarks. We introduce a novel relation between the cumulants of the chiral\norder parameter, i.e., the chiral condensate, and the correlations among the\nenergy levels of quarks, i.e., the eigenspectra of the massless QCD Dirac\noperator. This relation elucidates how the fluctuations of the chiral\ncondensate arise from the correlations within the infrared part of the energy\nspectra of quarks, and naturally leads to a generalization of the Banks-Casher\nrelation for the cumulants of the chiral condensate. Then, through (2+1)-flavor\nlattice QCD calculations using HISQ action with varying light quark masses\naround the chiral phase transition temperature, we demonstrate that the\ncorrelations among the infrared part of the Dirac eigenvalue spectra exhibit\nsame universal scaling behaviors as expected of the cumulants of the chiral\ncondensate. We find that these universal scaling behaviors extend up to the\nphysical values of the up and down quark masses.",
        "positive": "Instantons and Surface Tension at a First-Order Transition: We study the dynamics of the first order phase transition in the two\ndimensional 15-state Potts model, both at and off equilibrium. We find that\nphase changes take place through nucleation in both cases, and finite volume\neffects are described well through an instanton computation. Thus a dynamical\nmeasurement of the surface tension is possible. We find that the order-disorder\nsurface tension is compatible with perfect wetting. An accurate treatment of\nfluctuations about the instanton solution is seen to be of great importance."
    },
    {
        "anchor": "On the consistency of the Aoki-phase: Lattice QCD with two flavors of Wilson fermions can exhibit spontaneous\nbreaking of flavor and parity, with the resulting \"Aoki phase\" characterized by\nthe non-zero expectation value $<\\bar\\psi \\gamma_5 \\tau_3 \\psi>\\ne0$. This\nphenomenon can be understood using the chiral effective theory appropriate to\nthe Symanzik effective action. Within this standard analysis, the\nflavor-singlet pseudoscalar expectation value vanishes: $<i \\bar\\psi \\gamma_5\n\\psi>=0$. A recent reanalysis has questioned this understanding, arguing that\neither the Aoki-phase is unphysical, or that there are additional phases in\nwhich $<i \\bar\\psi \\gamma_5 \\psi>\\ne0$. The reanalysis uses the properties of\nprobability distribution functions for observables built of fermion fields and\nexpansions in terms of the eigenvalues of the hermitian Wilson-Dirac operator.\nHere I show that the standard understanding of the Aoki-phase is, in fact,\nconsistent with the approach used in the reanalysis. Furthermore, if one\nassumes that the standard understanding is correct, one can use the methods of\nthe reanalysis to derive lattice generalizations of the continuum sum rules of\nLeutwyler and Smilga.",
        "positive": "Surface worm algorithm for abelian Gauge-Higgs systems on the lattice: The Prokof'ev Svistunov worm algorithm was originally developed for models\nwith nearest neighbor interactions that in a high temperature expansion are\nmapped to systems of closed loops. In this work we present the surface worm\nalgorithm (SWA) which is a generalization of the worm algorithm concept to\nabelian Gauge-Higgs models on a lattice which can be mapped to systems of\nsurfaces and loops (dual representation). Using Gauge-Higgs models with gauge\ngroups Z(3) and U(1) we compare the SWA to the conventional approach and to a\nlocal update in the dual representation. For the Z(3) case we also consider\nfinite chemical potential where the conventional representation has a sign\nproblem which is overcome in the dual representation. For a wide range of\nparameters we find that the SWA clearly outperforms the local update."
    },
    {
        "anchor": "More on the properties of the first Gribov region in Landau gauge: Complete gauge-fixing beyond perturbation theory in non-Abelian gauge\ntheories is a non-trivial problem. This is particularly evident in covariant\ngauges, where the Gribov-Singer ambiguity gives an explicit formulation of the\nproblem. In practice, this is a problem if gauge-dependent quantities between\ndifferent methods, especially lattice and continuum methods, should be\ncompared: Only when treating the Gribov-Singer ambiguity in the same way is the\ncomparison meaningful. To provide a better basis for such a comparison the\nstructure of the first Gribov region in Landau gauge, a subset of all possible\ngauge copies satisfying the perturbative Landau gauge condition, will be\ninvestigated. To this end, lattice gauge theory will be used to investigate a\ntwo-dimensional projection of the region for SU(2) Yang-Mills theory in two,\nthree, and four dimensions for a wide range of volumes and discretizations.",
        "positive": "$B_c \\to B_{s(d)}$ form factors: We present results of the first lattice QCD calculations of $B_c \\to B_s$ and\n$B_c \\to B_d$ weak matrix elements. Results are derived from correlation\nfunctions computed on MILC Collaboration gauge configurations with lattice\nspacings between $0.12$ [fm] and $0.06$ [fm] including 2+1+1 flavours of\ndynamical sea quarks in the Highly Improved Staggered Quark (HISQ) formalism.\nForm factors across the entire physical $q^2$ range are then extracted and\nextrapolated to the physical-continuum limit. Two different formalisms are\nemployed for the bottom quark: non-relativistic QCD (NRQCD) and heavy-HISQ.\nChecking agreement between these two approaches is an important test of our\nstrategies for heavy quarks on the lattice."
    },
    {
        "anchor": "A practical solution to the sign problem in a matrix model for dynamical\n  compactification: The matrix model formulation of superstring theory offers the possibility to\nunderstand the appearance of 4d space-time from 10d as a consequence of\nspontaneous breaking of the SO(10) symmetry. Monte Carlo studies of this issue\nis technically difficult due to the so-called sign problem. We present a\npractical solution to this problem generalizing the factorization method\nproposed originally by two of the authors (K.N.A. and J.N.). Explicit Monte\nCarlo calculations and large-N extrapolations are performed in a simpler matrix\nmodel with similar properties, and reproduce quantitative results obtained\npreviously by the Gaussian expansion method. Our results also confirm that the\nspontaneous symmetry breaking indeed occurs due to the phase of the fermion\ndeterminant, which vanishes for collapsed configurations. We clarify various\ngeneric features of this approach, which would be useful in applying it to\nother statistical systems with the sign problem.",
        "positive": "Wilson fermions quark bilinears to three loops: Quark currents renormalization constants can in principle be safely computed\nin lattice perturbation theory. In practice, traditional lattice perturbative\ncomputations are quite cumbersome, so that so far only the first loop results\nwere available. By making use of Numerical Stochastic Perturbation Theory we\nreached three (and with less statistical precision even four) loops, both in\nquenched and in unquenched theory. Convergence properties of the series can be\nassessed and omparison with non perturbative results (where available) can be\nmade: high loops computations of renormalization constants can be a valuable\ntool for lattice QCD."
    },
    {
        "anchor": "Phases of the three-state Potts model in three spatial dimensions: The three-state Potts model is numerically investigated on three-dimensional\nsimple cubic lattices of up to \\(128^3\\) volume, concentrating on the\nneighborhood of the first-order phase transition separating the ordered and\ndisordered phases. In both phases clusters of like spins are observed with\nirregular boundaries. In the ordered phase the two different non-favored spins\nare found to attract each other with a long but finite range. As a result, the\nneighborhoods of the non-favored spins are interpreted as domains of the\ndisordered phase. This explains why the first-order phase transitions\nassociated with the global \\(Z_3\\) symmetry, including the SU(3) pure-gauge\none, are so weak.",
        "positive": "On the Analog Strong CP Problem in the $CP^{N-1}$ Models: Addressed is the question of whether a natural mechanism exists to resolve\nthe strong CP problem. The analogous issue for the two-dimensional $CP^{N-1}$\nmodels is analyzed using computer simulations."
    },
    {
        "anchor": "Consistency between L\u00fcscher's finite volume method and HAL QCD method\n  for two-baryon systems in lattice QCD: There exist two methods to study two-baryon systems in lattice QCD: the\ndirect method which extracts eigenenergies from the plateaux of the temporal\ncorrelator and the HAL QCD method which extracts observables from the non-local\npotential associated with the tempo-spatial correlator. Although the two\nmethods should give the same results theoretically, qualitatively different\nresults have been reported. Recently, we pointed out that the separation of the\nground state from the excited states is crucial to obtain sensible results in\nthe former, while both states provide useful signals in the latter. In this\npaper, we identify the contribution of each state in the direct method by\ndecomposing the two-baryon correlators into the finite-volume eigenmodes\nobtained from the HAL QCD method. We consider the $\\Xi\\Xi$ system in the\n$^1$S$_0$ channel at $m_\\pi = 0.51$ GeV in 2+1 flavor lattice QCD using the\nwall and smeared quark sources. We demonstrate that the \"pseudo-plateau\" at\nearly time slices (t = 1~2 fm) from the smeared source in the direct method\nindeed originates from the contamination of the excited states, and the true\nplateau with the ground state saturation is realized only at t > 5~15 fm\ncorresponding to the inverse of the lowest excitation energy. We also\ndemonstrate that the two-baryon operator can be optimized by utilizing the\nfinite-volume eigenmodes, so that (i) the finite-volume energy spectra from the\nHAL QCD method agree with those from the optimized temporal correlator and (ii)\nthe correct spectra would be accessed in the direct method only if highly\noptimized operators are employed. Thus we conclude that the long-standing issue\non the consistency between the L\\\"uscher's finite volume method and the HAL QCD\nmethod for two baryons is now resolved: They are consistent with each other\nquantitatively only if the excited contamination is properly removed in the\nformer.",
        "positive": "Two Flavors of Staggered Fermions with Smeared Links: Staggered fermions with smeared links can have greatly improved chiral\nproperties. In a recent paper we introduced a simple and effective method to\nsimulate four flavors of staggered smeared link fermions. In this work we\nextend the four flavor method to two flavors. We define the two flavor action\nby the square root of the four flavor fermionic determinant and show that by\nusing a polynomial approximation the two flavor action can be evaluated with\nthe necessary accuracy. We test this method by studying the finite temperature\nphase structure with hypercubic smeared (HYP) link staggered action on N_t=4\ntemporal lattices."
    },
    {
        "anchor": "QCD with two flavors of Wilson fermions: The QCD vacuum, the Aoki vacuum\n  and other vacua: We discuss the vacuum structure of QCD with two flavors of Wilson fermions.\nWe derive two possible scenarios: (i) If the spectral density\n$\\rho_U(\\lambda,\\kappa)$ of the overlap hamiltonian in a fixed background gauge\nfield is not symmetric in $\\lambda$, Hermiticity is violated and Hermiticity\nviolation effects could influence numerical determinations of the $\\eta$ meson\nmass if we are not near enough to the continuum limit, where Hermiticity should\nbe recovered; (ii) otherwise we argue that, under certain assumptions, new\nphases appear beside the Aoki phase, which can be characterized by a\nnonvanishing vacuum expectation value of\n$i\\bar\\psi_u\\gamma_5\\psi_u+i\\bar\\psi_d\\gamma_5\\psi_d$, and with vacuum states\nthat cannot be connected with the Aoki vacua by parity-flavor symmetry\ntransformations. Quenched numerical simulations suggest that the second\nscenario is more likely realized.",
        "positive": "Masses and decay constants of the B-system in Lattice QCD: Heavy-light bound states are studied in Lattice QCD with emphasis on\nparameters of the B-system relevant to experiment. Results are obtained on\nlattices with lattice spacings from about 0.15 fm to 0.06 fm corresponding to\n$\\beta=5.74, 6.0$ and 6.26, and covering sizes from about 0.7 fm to 2 fm. From\nour results at the infinite quark mass limit and from propagating heavy quarks\nwith mass of about 1-2.5 GeV we extrapolate to the b-quark mass to obtain the\ndecay constant of the B-meson as well as the mass of $\\Lambda_b$ in the\ncontinuum. The necessary extrapolations introduce rather large errors and lead\nto the value $f_B=180(50)$ MeV. We compare with the results from other lattice\ngroups as well as with predictions coming from sum rules. The phenomenological\nconsequences of this value of $f_B$, together with new experimental\nconstraints, are briefly discussed."
    },
    {
        "anchor": "Thimble regularisation of YM fields: crunching a hard problem: Thimble regularisation of Yang Mills theories is still to a very large extent\nterra incognita. We discuss a couple of topics related to this big issue. 2d YM\ntheories are in principle good candidates as a working ground. An analytic\nsolution is known, for which one can switch from a solution in terms of a sum\nover characters to a form which is a sum over critical points. We would be\ninterested in an explicit realisation of this mechanism in the lattice\nregularisation, which is actually quite hard to work out. A second topic is the\ninclusion of a topological term in the lattice theory, which is the prototype\nof a genuine sign problem for pure YM fields. For both these challenging\nproblems we do not have final answers. We present the current status of our\nstudy.",
        "positive": "Investigation of New Methods for Numerical Stochastic Perturbation\n  Theory in $\\varphi^4$ Theory: Numerical stochastic perturbation theory is a powerful tool for estimating\nhigh-order perturbative expansions in lattice field theory. The standard\nalgorithms based on the Langevin equation, however, suffer from several\nlimitations which in practice restrict the potential of this technique. In this\nwork we investigate some alternative methods which could in principle improve\non the standard approach. In particular, we present a study of the recently\nproposed Instantaneous Stochastic Perturbation Theory, as well as a formulation\nof numerical stochastic perturbation theory based on Generalized Hybrid\nMolecular Dynamics algorithms. The viability of these methods is investigated\nin $\\varphi^4$ theory."
    },
    {
        "anchor": "The Continuum Limit of One-Dimensional Quantum Regge Calculus with\n  Massive Bosons: The most essential problems in Regge calculus discretization are the\ndefinitions of the partition function and the integral measure for\nlink--length. In recent work, by considering the one--dimensional case, it was\nsuggested that we should define the partition function in a certain form. But\nin that work, the model which authors used was over simplified hence the\nconclusions may be unreliable. To confirm their claim, we consider a case that\nis more realistic.",
        "positive": "Physical Point Simulation in 2+1 Flavor Lattice QCD: We present the results of the physical point simulation in 2+1 flavor lattice\nQCD with the nonperturbatively $O(a)$-improved Wilson quark action and the\nIwasaki gauge action at $\\beta=1.9$ on a\n  $32^3 \\times 64$ lattice. The physical quark masses together with the lattice\nspacing is determined with $m_\\pi$, $m_K$ and $m_\\Omega$ as physical inputs.\nThere are two key algorithmic ingredients to make possible the direct\nsimulation at the physical point: One is the mass-preconditioned\ndomain-decomposed HMC algorithm to reduce the computational cost. The other is\nthe reweighting technique to adjust the hopping parameters exactly to the\nphysical point. The physics results include the hadron spectrum, the quark\nmasses and the pseudoscalar meson decay constants. The renormalization factors\nare nonperturbatively evaluated with the Schr{\\\"o}dinger functional method. The\nresults are compared with the previous ones obtained by the chiral\nextrapolation method."
    },
    {
        "anchor": "Determining QCD Low-Energy Couplings from lattice simulations: Different strategies for the computation of QCD low-energy couplings by\nmatching lattice QCD with the chiral effective theory are reviewed. After\nrecalling the main features of the chiral effective theory in the epsilon- and\np- regimes, the current status of the determination of leading order (Sigma, F)\nand next-to-leading order (l_i, L_i) low-energy constants is summarised,\nfocusing in particular on recent results obtained with N_f=2 and N_f=2+1\nsimulations.",
        "positive": "Quantum geometry of 2d gravity coupled to unitary matter: We show that there exists a divergent correlation length in 2d quantum\ngravity for the matter fields close to the critical point provided one uses the\ninvariant geodesic distance as the measure of distance. The corresponding\nreparameterization invariant two-point functions satisfy all scaling relations\nknown from the ordinary theory of critical phenomena and the KPZ exponents are\ndetermined by the power-like fall off of these two-point functions. The only\ndifference compared to flat space is the appearance of a dynamically generated\nfractal dimension d_h in the scaling relations. We analyze numerically the\nfractal properties of space-time for Ising and three-states Potts model coupled\nto 2d dimensional quantum gravity using finite size scaling as well as small\ndistance scaling of invariant correlation functions. Our data are consistent\nwith d_h=4, but we cannot rule out completely the conjecture d_H =\n-2\\alpha_1/\\alpha_{-1}, where \\alpha_{-n} is the gravitational dressing\nexponent of a spin-less primary field of conformal weight (n+1,n+1). We compute\nthe moments <L^n> and the loop-length distribution function and show that the\nfractal properties associated with these observables are identical, with good\naccuracy, to the pure gravity case."
    },
    {
        "anchor": "O(a^2) cutoff effects in lattice Wilson fermion simulations: In this paper we propose to interpret the large discretization artifacts\naffecting the neutral pion mass in maximally twisted lattice QCD simulations as\nO(a^2) effects whose magnitude is roughly proportional to the modulus square of\nthe (continuum) matrix element of the pseudoscalar density operator between\nvacuum and one-pion state. The numerical size of this quantity is determined by\nthe dynamical mechanism of spontaneous chiral symmetry breaking and turns out\nto be substantially larger than its natural magnitude set by the value of\nLambda_QCD.",
        "positive": "Isovector and flavor diagonal charges of the nucleon from 2+1+1 flavor\n  QCD: We present high-statistics results for the isovector and flavor diagonal\ncharges of the proton using 11 ensembles of 2+1+1 flavor HISQ fermions. In the\nisospin symmetric limit, results for the neutron are given by the $u\n\\leftrightarrow d$ interchange. A chiral-continuum fit with leading order\ncorrections was made to extract the connected and disconnected contributions in\nthe continuum limit and at $M_\\pi=135$ MeV. All results are given in the\n$\\overline{MS}$ scheme at 2 GeV. The isovector charges, $g_A^{u-d} =\n1.218(25)(30)$, $g_S^{u-d} = 1.022(80)(60) $ and $g_T^{u-d} = 0.989(32)(10)$,\nare used to obtain low-energy constraints on novel scalar and tensor\ninteractions, $\\epsilon_{S}$ and $\\epsilon_{T}$, at the TeV scale. The flavor\ndiagonal axial charges are: $g_A^u \\equiv \\Delta u \\equiv \\langle 1\n\\rangle_{\\Delta u^+} = 0.777(25)(30)$, $g_A^d \\equiv \\Delta d \\equiv \\langle 1\n\\rangle_{\\Delta d^+} = -0.438(18)(30)$, and $g_A^s \\equiv \\Delta s \\equiv\n\\langle 1 \\rangle_{\\Delta s^+} = -0.053(8)$. Their sum gives the total quark\ncontribution to the proton spin, $\\sum_{q=u,d,s} (\\frac{1}{2} \\Delta q) =\n0.143(31)(36)$. This result is in good agreement with the recent COMPASS\nanalysis $0.13 < \\frac{1}{2} \\Delta \\Sigma < 0.18$. Implications of results for\nthe flavor diagonal tensor charges, $g_T^u = 0.784(28)(10)$, $g_T^d =\n-0.204(11)(10)$ and $g_T^s = -0.0027(16)$ for constraining the quark electric\ndipole moments and their contributions to the neutron electric dipole moment\nare discussed. These flavor diagonal charges also give the strength of the\ninteraction of dark matter with nucleons via axial and tensor mediators."
    },
    {
        "anchor": "Ordered vs Disordered: Correlation Lengths of 2D Potts Models at \u03b2_t: We performed Monte Carlo simulations of two-dimensional $q$-state Potts\nmodels with $q=10,15$, and $20$ and measured the spin-spin correlation function\nat the first-order transition point $\\beta_t$ in the disordered and ordered\nphase. Our results for the correlation length $\\xi_d(\\beta_t)$ in the\ndisordered phase are compatible with an analytic formula. Estimates of the\ncorrelation length $\\xi_o(\\beta_t)$ in the ordered phase yield strong numerical\nevidence that $R \\equiv \\xi_o(\\beta_t)/\\xi_d(\\beta_t) = 1$.",
        "positive": "Critical point and scale setting in SU(3) plasma: An update: We explore a method developed in statistical physics which has been argued to\nhave exponentially small finite-volume effects, in order to determine the\ncritical temperature Tc of pure SU(3) gauge theory close to the continuum\nlimit. The method allows us to estimate the critical coupling betac of the\nWilson action for temporal extents up to Nt ~ 20 with < 0.1% uncertainties.\nMaking use of the scale setting parameters r0 and sqrt{t0} in the same range of\nbeta-values, these results lead to the independent continuum extrapolations Tc\nr0 = 0.7457(45) and Tc sqrt{t0} = 0.2489(14), with the latter originating from\na more convincing fit. Inserting a conversion of r0 from literature\n(unfortunately with much larger errors) yields Tc / LambdaMSbar = 1.24(10)."
    },
    {
        "anchor": "QCD Thermodynamics with an almost realistic quark mass spectrum: We will report on the status of a new large scale calculation of\nthermodynamic quantities in QCD with light up and down quarks corresponding to\nan almost physical light quark mass value and a heavier strange quark mass.\nThese calculations are currently being performed on the QCDOC Teraflops\ncomputers at BNL. We will present new lattice calculations of the transition\ntemperature and various susceptibilities reflecting properties of the chiral\ntransition. All these quantities are of immediate interest for heavy ion\nphenomenology.",
        "positive": "Understanding the nature of baryon resonances: This presentation opens with a brief review of lattice QCD calculations\nshowing the $2s$ radial excitation of the nucleon sits at approximately 2 GeV,\nwell above the Roper resonance position. We then proceed to reconcile this\nobservation with experimental scattering data. While the idea of dressing\nquark-model states in a coupled-channel analysis to describe scattering data\nhas been around for decades, it's now possible to bring these descriptions to\nthe finite-volume of lattice QCD for confrontation with lattice-QCD\ncalculations. This combination of lattice QCD and experiment demands that we\nreconsider our preconceived notions about the quark-model and its excitation\nspectrum. We close with a discussion of an unanticipated resolution to the\nmissing baryon resonances problem."
    },
    {
        "anchor": "Investigating some technical improvements to glueball calculations: We briefly discuss some issues concerning including the pseudoscalar glueball\ninterpolating operators into the variational basis for computing the masses of\nthe eta and etaprime mesons. As a start we present some preliminary results for\nthe correlators from pseudoscalar glueball operators on nf = 2+1+1 twisted mass\ngauge configurations. Preliminary results for the effect of open boundary\nconditions on the masses of three glueballs computed in quenched QCD are\npresented. The statistics of glueball correlators are briefly discussed.",
        "positive": "Fast Fermion Monte Carlo: Three possibilities to speed up the Hybrid Monte Carlo algorithm are\ninvestigated. Changing the step-size adaptively brings no practical gain. On\nthe other hand, substantial improvements result from using an approximate\nHamiltonian or a preconditioned action."
    },
    {
        "anchor": "Domain-Wall Induced Quark Masses in Topologically-Nontrivial Background: In the domain-wall formulation of chiral fermion, the finite separation\nbetween domain-walls ($L_s$) induces an effective quark mass ($m_{\\rm eff}$)\nwhich complicates the chiral limit. In this work, we study the size of the\neffective mass as the function of $L_s$ and the domain-wall height $m_0$ by\ncalculating the smallest eigenvalue of the hermitian domain-wall Dirac operator\nin the topologically-nontrivial background fields. We find that, just like in\nthe free case, $m_{\\rm eff}$ decreases exponentially in $L_s$ with a rate\ndepending on $m_0$. However, quantum fluctuations amplify the wall effects\nsignificantly. Our numerical result is consistent with a previous study of the\neffective mass from the Gell-Mann-Oakes-Renner relation.",
        "positive": "Center Dominance Recovered: Direct Laplacian Center Gauge: We introduce a variation of direct maximal center gauge fixing: the \"direct\nLaplacian\" center gauge. The new procedure consists of first fixing to the\nLaplacian adjoint Landau gauge, followed by overrelaxation to the nearby Gribov\ncopy of the direct maximal center gauge. Certain shortcomings of maximal center\ngauge, associated with Gribov copies, are overcome in the new gauge, in\nparticular center dominance is recovered."
    },
    {
        "anchor": "Symmetries of mesons after unbreaking of chiral symmetry and their\n  string interpretation: Using the chirally invariant overlap Dirac operator we remove its\nlowest-lying quasizero modes from the valence quark propagators and study\nevolution of isovector mesons with J=1. At the truncation level about 50 MeV\nSU(2)_L \\times SU(2)_R and U(1)_A symmetries get restored. However, we observe\na degeneracy not only within the chiral and U(1)_A multiplets, but also a\ndegeneracy of all possible chiral multiplets, i.e., the observed quantum levels\nhave a symmetry larger than U(2)_L \\times U(2)_R and their energy does not\ndepend on the spin orientation of quarks and their parities. We offer a\npossible interpretation of these energy levels as the quantum levels of the\ndynamical QCD string. The structure of the radial J=1 spectrum is compatible\nwith E =(n_r +1)\\hbar\\omega with \\hbar\\omega = 900 \\pm 70 MeV.",
        "positive": "The transfer matrix with Kogut-Susskind fermions: A transfer matrix for gauge theories on a lattice with Kogut-Susskind\nfermions in the flavour basis is constructed and some difficulties in the\nspin-diagonal basis are pointed out."
    },
    {
        "anchor": "Lattice study on QCD-like theory with exact center symmetry: We investigate QCD-like theory with exact center symmetry, with emphasis on\nthe finite-temperature phase transition concerning center and chiral\nsymmetries. On the lattice, we formulate center symmetric $SU(3)$ gauge theory\nwith three fundamental Wilson quarks by twisting quark boundary conditions in a\ncompact direction ($Z_3$-QCD model). We calculate the expectation value of\nPolyakov loop and the chiral condensate as a function of temperature on 16^3 x\n4 and 20^3 x 4 lattices along the line of constant physics realizing\n$m_{PS}/m_{V}=0.70$. We find out the first-order center phase transition, where\nthe hysteresis of the magnitude of Polyakov loop exists depending on\nthermalization processes. We show that chiral condensate decreases around the\ncritical temperature in a similar way to that of the standard three-flavor QCD,\nas it has the hysteresis in the same range as that of Polyakov loop. We also\nshow that the flavor symmetry breaking due to the twisted boundary condition\ngets qualitatively manifest in the high-temperature phase. These results are\nconsistent with the predictions based on the chiral effective model in the\nliterature. Our approach could provide novel insights to the nonperturbative\nconnection between the center and chiral properties.",
        "positive": "Nucleon Transversity Distribution in the Continuum and Physical Mass\n  Limit from Lattice QCD: We report a state-of-the-art lattice QCD calculation of the isovector quark\ntransversity distribution of the proton in the continuum and physical mass\nlimit using large-momentum effective theory. The calculation is done at four\nlattice spacings $a=\\{0.098,0.085,0.064,0.049\\}$~fm and various pion masses\nranging between $220$ and $350$ MeV, with proton momenta up to $2.8$ GeV. The\nresult is non-perturbatively renormalized in the hybrid scheme with self\nrenormalization which treats the infrared physics at large correlation distance\nproperly, and extrapolated to the continuum, physical mass and infinite\nmomentum limit. We also compare with recent global analyses for the nucleon\nisovector quark transversity distribution."
    },
    {
        "anchor": "G parity boundary conditions and Delta I = 1/2, K to pi pi decays: The use of G-parity boundary conditions to compute Delta I = 1/2, K to pi pi\ndecays is reviewed and a method to consistently treat both the pions and kaon\nin full QCD proposed. This approach creates a physical, final-state, pion\nmomentum using a 3 fm box and avoids statistical noise coming from pions with\nsmaller momentum.",
        "positive": "One-loop lattice study of composite bilinear operators in Supersymmetric\n  QCD: We study 4-dimensional SQCD with gauge group SU(Nc) and Nf flavors of chiral\nsupermultiplets on the lattice. We perform extensive calculations of matrix\nelements and renormalization factors of composite operators in Perturbation\nTheory. In particular, we compute the renormalization factors of quark and\nsquark bilinears, as well as their mixing at the quantum level with gluino and\ngluon bilinear operators. From these results we construct correctly\nrenormalized composite operators, which are free of mixing effects and may be\nemployed in non-perturbative studies of Supersymmetry. All our calculations\nhave been performed with massive matter fields, in order to regulate the\ninfrared singularities which are inherent in renormalizing squark bilinears.\nFurthermore, the quark and squark propagators are computed in momentum space\nwith nonzero masses.\n  This work is a feasibility study for lattice computations relevant to a\nnumber of observables, such as spectra and distribution functions of hadrons,\nbut in the context of supersymmetric QCD, as a forerunner to lattice\ninvestigations of SUSY extensions of the Standard Model."
    },
    {
        "anchor": "The First Moment of the Kaon Distribution Amplitude from N_f=2+1 Domain\n  Wall Fermions: We present a lattice computation of the first moment of the kaon's\nleading-twist distribution amplitude. We use ensembles with 2+1 dynamical\nflavours of domain wall fermions and the Iwasaki gauge action from the RBC and\nUKQCD joint dataset. We observe the expected chiral behaviour and obtain\n<\\xi>(2GeV)=3/5a_K^1(2GeV)=0.032(3), which agrees very well with other results\nobtained using QCD sum-rules and the recent lattice result from the UKQCD/QCDSF\ncollaboration.",
        "positive": "Peeping into the SU(2) Gauge Vacuum: We study thermalised configurations of SU(2) gauge fields by cooling. An\nanalysis of the effect of cooling is presented and global and statistical\ninformation is extracted."
    },
    {
        "anchor": "Hybrid meson decay from lattice QCD: Besides the conventional hadrons containing valence quarks and valence\nantiquarks, quantum chromodynamics (QCD) suggests the existence of the hybrid\nhadrons containing valence gluons in addition to the quarks and antiquarks, and\nsome experiments may have found some. A decisive experimental confirmation of\nits existence, however, is still needed. At present, lattice simulations have\noffered the practicable ways of theoretically guiding us to search for the\nhybrid states.\n  In this dissertation, we study the spectroscopy and the decay rate of the\nheavy hybrid mesons made of a heavy $b$ quark, a heavy $\\bar b$ antiquark, and\na gluon ($b\\bar{b}g$) to selected channels, and use lattice methods to extract\nthe transition matrix elements in full QCD. We are particular interested in the\nspin-exotic hybrid mesons.\n  For sufficiently heavy quarks (e.g., $b$ quark), we use the leading\nBorn-Oppenheimer (LBO) approximation to calculate the static potential energy\nat all $b\\bar{b}$ separations. Then, by solving the Schr\\\"odinger equation with\nthis potential, we reconstruct the motion of the heavy quarks. In a similar way\nwe can determine decay rates. In this dissertation, we use the numerical\nlattice method to calculate the mass of the $f_0$ meson at a single lattice\nspacing and light quark mass, namely, $m_{f_0} = (768 \\pm 136)$ MeV. Most of\nall we consider the decay channels involving the production of a scalar meson.\nWe obtain the partial decay rate ($\\Gamma$) for the channel $ H \\rightarrow\n\\chi_b + \\pi + \\pi $, namely, $ \\Gamma = 3.62(98)$ MeV. All of our results are\nconsistent with those of other researchers. Knowledge of the masses and the\ndecay rates should help us considerably in experimental searches for the hybrid\nmesons.",
        "positive": "A Solution to the Strong CP Problem: One may argue that QCD solves the strong CP problem by itself, without having\nto introduce new symmetries and particles. To test this idea, a lattice\nsimulation is performed. The problem is investigated in the CP$^3$ model first.\nIt is found that the model has a first order phase transition in $\\theta$ from\na confining phase at small $\\theta$ to a deconfining phase at large $\\theta$,\nand that the critical value of $\\theta$ decreases towards zero as $\\beta$ is\ntaken to infinity. This suggests that $\\theta$ is tuned to zero in the\ncontinuum limit. Preliminary studies of the SU(2) Yang-Mills theory in four\ndimensions show a phase transition in $\\theta$ as well, so that it is quite\nlikely that the strong CP problem in QCD is solved along the same line."
    },
    {
        "anchor": "CP-PACS results for light hadron spectrum in quenched and two-flavor\n  full QCD: We present a summary of our results for the light hadron spectrum in quenched\nlattice QCD and preliminary ones in two-flavor full QCD. For the quenched\nhadron spectrum we find that the mass formulae predicted by quenched chiral\nperturbation theory(QChPT) give a good description of our results. Employing\nthe QChPT mass formulae for chiral extrapolations we conclude that the mass\nspectrum in the continuum limit deviates unambiguously and systematically from\nexperiment. For our two-flavor full QCD results we focus on the dynamical quark\neffects on the light hadron spectrum.",
        "positive": "Lattice gauge theory for Haldane conjecture and central-branch Wilson\n  fermion: We develop the $(1+1)$d lattice $U(1)$ gauge theory in order to define\n$2$-flavor massless Schwinger model, and discuss its connection with Haldane\nconjecture. We propose to use the central-branch Wilson fermion, which is\ndefined by relating the mass, $m$, and the Wilson parameter, $r$, as $m+2r=0$.\nThis setup gives two massless Dirac fermions in the continuum limit, and it\nturns out that no fine-tuning of $m$ is required because the extra $U(1)$\nsymmetry at the central branch, $U(1)_{\\bar{V}}$, prohibits the additive mass\nrenormalization. Moreover, we show that Dirac determinant is positive\nsemi-definite and this formulation is free from the sign problem, so the Monte\nCarlo simulation of the path integral is possible. By identifying the symmetry\nat low energy, we show that this lattice model has the mixed 't Hooft anomaly\nbetween $U(1)_{\\bar{V}}$, lattice translation, and lattice rotation. We discuss\nits relation to the anomaly of half-integer anti-ferromagnetic spin chains, so\nour lattice gauge theory is suitable for numerical simulation of Haldane\nconjecture. Furthermore, it gives new and strict understanding on parity-broken\nphase (Aoki phase) of $2$d Wilson fermion."
    },
    {
        "anchor": "Discretization effects and the scalar meson correlator in mixed-action\n  lattice simulations: We study discretization effects in a mixed-action lattice theory with\ndomain-wall valence quarks and Asqtad-improved staggered sea quarks. At the\nlevel of the chiral effective Lagrangian, discretization effects in the\nmixed-action theory give rise to two new parameters as compared to the lowest\norder Lagrangian for staggered fermions -- the residual quark mass, m_res, and\nthe mixed valence-sea meson mass-splitting, Delta_mix. We find that the size of\nm_res is approximately four times smaller than our lightest valence quark mass\non our coarser lattice spacing, and comparable to that of simulations by RBC\nand UKQCD. We also find that the size of Delta_mix is comparable to the\nsmallest of the staggered meson taste-splittings measured by MILC. Because\nlattice artifacts are different in the valence and sea sectors of the\nmixed-action theory, they give rise to unitarity-violating effects that\ndisappear in the continuum limit. Such effects are expected to be mild for many\nquantities of interest, but are significant in the case of the isovector scalar\n(a_0) correlator. Specifically, once m_res, Delta_mix, and two other parameters\nthat can be determined from the light pseudoscalar spectrum are known, the\ntwo-particle intermediate state \"bubble\" contribution to the scalar correlator\nis completely predicted within mixed-action chiral perturbation theory\n(MAChPT). We find that the behavior of the scalar meson correlator is\nquantitatively consistent with the MAChPT prediction; this supports the claim\nthat MAChPT describes the dominant unitarity-violating effects in the\nmixed-action theory and can be used to remove lattice artifacts and recover\nphysical quantities.",
        "positive": "First order signatures in 4D pure compact U(1) gauge theory with\n  toroidal and spherical topologies: We study the pure compact U(1) gauge theory with the extended Wilson action\n(\\beta, \\gamma couplings) by finite size scaling techniques, in lattices\nranging from L=6 to L=24 in the region of \\gamma <= 0 with toroidal and\nspherical topologies. The phase transition presents a double peak structure\nwhich survives in the thermodynamical limit in the torus. In the sphere the\nevidence support the idea of a weaker, but still first order, phase transition.\nFor negative values of gamma the transition becomes weaker and larger lattices\nare needed to find its asymptotic behaviour. Along the transient region the\nbehaviour is the typical one of a weak first order transition for both\ntopologies, with a region where 1/d < nu < 0.5, which becomes nu compatible\nwith 1/d when larger lattices are used."
    },
    {
        "anchor": "Automated lattice perturbation theory: I review recent developments in automated lattice perturbation theory.\nStarting with an overview of lattice perturbation theory, I focus on the three\nautomation packages currently \"on the market\": HiPPy/HPsrc, Pastor and\nPhySyCAl. I highlight some recent applications of these methods, particularly\nin B physics. In the final section I briefly discuss the related, but distinct,\napproach of numerical stochastic perturbation theory.",
        "positive": "Quenched Results for Light Quark Physics with Overlap Fermions: We present results of a quenched QCD simulation with overlap fermions on a\nlattice of volume V = 16^3X32 at beta=6.0, which corresponds approximatively to\na lattice cutoff of 2 GeV and an extension of 1.4 fm. From the two-point\ncorrelation functions of bilinear operators we extract the pseudoscalar meson\nmasses and the corresponding decay constants. From the GMOR relation we\ndetermine the chiral condensate and, by using the K-meson mass as experimental\ninput, we compute the sum of the strange and average up-down quark masses (m_s\n+ \\hat m). The needed logarithmic divergent renormalization constant Z_S is\ncomputed with the RI/MOM non-perturbative renormalization technique. Since the\noverlap preserves chiral symmetry at finite cutoff and volume, no divergent\nquark mass and chiral condensate additive renormalizations are required and the\nresults are O(a) improved."
    },
    {
        "anchor": "The dependence of observables on action parameters: Many applications in Lattice field theory require to determine the Taylor\nseries of observables with respect to action parameters. A primary example is\nthe determination of electromagnetic corrections to hadronic processes. We show\ntwo possible solutions to this general problem, one based on reweigting, that\ncan be considered a generalization of the RM123 method. The other based on the\nideas of Numerical Stochastic Perturbation Theory (NSPT) in the Hamiltonian\nformulation. We show that 1) the NSPT-based approach shows a much reduced\nvariance in the determination of the Taylor coefficients, and 2) That both\napproaches are related by a change of variables. Numerical results are shown\nfor the case of $\\lambda-\\phi^4$ in 4 dimensions, but we expect these\nobservations to be general. We conclude by commenting on the possible use of\nMachine Learning techniques to find similar change of variables that can\npotentially reduce the variance in Taylor coefficients.",
        "positive": "Study of Hadron Masses with Faddeev-Popov Eigenmode Projection in the\n  Coulomb Gauge: Using SU(3) lattice QCD, we investigate role of spatial gluons for hadron\nmasses in the Coulomb gauge, considering the relation between QCD and the quark\nmodel. From the Coulomb-gauge configurations at the quenched level on a $16^3\n\\times 32$ lattice at $\\beta$ = 6.0, we consider the $\\vec{A} = 0$ projection,\nwhere all the spatial gluon fields are set to zero. In this projection, the\ninter-quark potential is unchanged. We investigate light hadron masses and find\nthat nucleon and delta baryon masses are almost degenerate. This result\nsuggests that the N-$\\Delta$ mass difference arises from the color-magnetic\ninteractions, which is consistent with the quark model picture. Next, as a\ngeneralization of this projection, we expand spatial gluon fields in terms of\nFaddeev-Popov eigenmodes and leave only some partial components. We find that\nthe ${\\rm N}-\\Delta$ and $0^{++}-2^{++}$ glueball mass splittings are almost\nreproduced only with 1 \\% low-lying components. This suggests that low-lying\ncolor-magnetic interaction leads to the hadron mass splitting."
    },
    {
        "anchor": "Dual representation for 1+1 dimensional fermions interacting with 3+1\n  dimensional U(1) gauge fields: We study a system of nanowires, i.e., the theory of 1+1 dimensional massless\nfermions interacting with 3+1 dimensional U(1) gauge fields. When allowing for\nnon-zero chemical potentials, this system has a complex action problem in the\nconventional formulation. We show that the partition sum can be mapped to a\ndual representation where the fermions correspond to dimers and oriented loops\non 2-dimensional planes embedded in 4 dimensions. The dual degrees of freedom\nfor the gauge fields are surfaces that either are closed or bounded by the\nfermion loops. In terms of the dual variables the complex action problem is\novercome and Monte Carlo simulations are possible for arbitrary chemical\npotentials.",
        "positive": "First results from simulations of supersymmetric lattices: We conduct the first numerical simulations of lattice theories with exact\nsupersymmetry arising from the orbifold constructions of\n\\cite{Cohen:2003xe,Cohen:2003qw,Kaplan:2005ta}. We consider the $\\cQ=4$ theory\nin $D=0,2$ dimensions and the $\\cQ=16$ theory in $D=0,2,4$ dimensions. We show\nthat the U(N) theories do not possess vacua which are stable\nnon-perturbatively, but that this problem can be circumvented after truncation\nto SU(N). We measure the distribution of scalar field eigenvalues, the spectrum\nof the fermion operator and the phase of the Pfaffian arising after integration\nover the fermions. We monitor supersymmetry breaking effects by measuring a\nsimple Ward identity. Our results indicate that simulations of ${\\cal N}=4$\nsuper Yang-Mills may be achievable in the near future."
    },
    {
        "anchor": "Two-dimensional gluon propagators in maximally Abelian gauge in SU(2)\n  Lattice QCD: Using SU(2) lattice QCD in two dimensions, we study diagonal and off-diagonal\ngluon propagators in the maximally Abelian gauge (MAG) with U(1)$_3$ Landau\ngauge fixing. These propagators are investigated both in momentum space and\ncoordinate space. The Monte Carlo simulation is performed at $\\beta=7.99,\n30.5,$ and $120$ on $62^2, 128^2,$ and $256^2$ at the quenched level. In the\nmomentum space, the transverse component of the diagonal gluon propagator shows\nsuppression with increasing $\\beta$ in the infrared region and the dressing\nfunction at $\\beta=120$ has a maximum at $p^2 \\simeq 4$GeV, while the\ntransverse component of the off-diagonal gluon propagator does not show the\n$\\beta$-dependence and the dressing function does not have a maximum. This\nbehavior indicates that the effect of the Gribov copies is found for the\ndiagonal gluon, consistent with the result obtained by the Gribov-Zwanziger\naction in the MAG. In addition, this behavior supports that the Abelian\ndominance is not found in two dimensions. In the coordinate space, the diagonal\ngluon propagator decreases as $\\beta$ increases at long distance. In\nparticular, at $\\beta=120$ the diagonal propagator decreases more rapidly with\nincreasing distance than the off-diagonal propagator. These behaviors also\nindicate the presence of Gribov copies and no Abelian dominance in two\ndimensions. Furthermore, we also study these propagators at\nzero-spatial-momentum. The result suggests that all of the spectral functions\nof diagonal and off-diagonal gluons would have negative regions and thus they\nshow the violation of the Kallen-Lehmann representation.",
        "positive": "The static quark potential in full QCD: We report results on the static quark potential in two-flavor full QCD. The\ncalculation is performed for three values of lattice spacing $a^{-1}\\approx\n0.9, 1.3$ and 2.5 GeV on $12^3{\\times}24, 16^3{\\times}32$ and $24^3{\\times}48$\nlattices respectively, at sea quark masses corresponding to $m_\\pi/m_\\rho\n\\approx 0.8-0.6$. An RG-improved gauge action and a tadpole-improved SW clover\nquark action are employed. We discuss scaling of $m_{\\rho}/\\sqrt{\\sigma}$ and\neffects of dynamical quarks on the potential."
    },
    {
        "anchor": "Techniques for using the overlap-Dirac operator to calculate hadron\n  spectroscopy: We report on our progress in using the overlap-Dirac fermion operator in\nsimulations of lattice QCD. We have investigated the Lanczos based method of\nBorici, as well as various rational approximations, to calculate the step\nfunction in the overlap-Dirac operator. The QCD simulations were performed at\nbeta = 5.85 with a lattice volume of 8**3*32.",
        "positive": "Lattice gauge theory with staggered fermions: how, where, and why (not): Many results from lattice QCD of broad importance to particle and nuclear\nphysics are obtained with 2+1 flavors of staggered sea quarks. In the continuum\nlimit, staggered fermions yield four species, called tastes. To reduce the\nnumber of tastes to one (per flavor), the simulation employs the fourth root of\nthe four-taste staggered fermion determinant. This talk surveys evidence in\nfavor of this procedure, refutes recent criticisms, and reviews recent\nalgorithmic and technical improvements. Physics results are covered in other\nplenary talks."
    },
    {
        "anchor": "The Volume Source Technique for flavor singlets: a second look: We reconsider the Volume Source Technique (VST) for the determination of\nflavor singlet quantities on the lattice. We point out a difficulty arising in\nthe case of fermions in real representations of the gauge group and propose an\nimproved version of the method (IVST) based on random gauge transformations of\nthe background configuration. We compare the performance of IVST with the\nmethod based on stochastic estimators (SET). We consider the case of the N=1\nSupersymmetric Yang-Mills Theory (SYM), where just one fermionic flavor is\npresent, the gluino in the adjoint representation, and only flavor singlet\nstates are possible. The work is part of an inclusive analysis of the spectrum\nof the lightest particles of the theory, based on the simulation of the model\non a $16^3\\cdot32$ lattice with dynamical gluinos in the Wilson scheme.",
        "positive": "The SU(3) spin model with chemical potential by series expansion\n  techniques: The $SU(3)$ spin model with chemical potential corresponds to a simplified\nversion of QCD with static quarks in the strong coupling regime. It has been\nstudied previously as a testing ground for new methods aiming to overcome the\nsign problem of lattice QCD. In this work we show that the equation of state\nand the phase structure of the model can be determined to reasonable accuracy\nby a linked cluster expansion. In particular, we compute the free energy to\n14-th order in the nearest neighbour coupling. The resulting predictions for\nthe equation of state and the location of the critical end point agree with\nnumerical determinations to ${\\cal O}(1\\%)$ and ${\\cal O}(10\\%)$, respectively.\nWhile the accuracy for the critical couplings is still limited at the current\nseries depth, the approach is equally applicable at zero and non-zero imaginary\nor real chemical potential, as well as to effective QCD Hamiltonians obtained\nby strong coupling and hopping expansions."
    },
    {
        "anchor": "Gauge-invariant renormalization of fermion bilinears and energy-momentum\n  tensor on the lattice: We study a gauge-invariant renormalization scheme (GIRS) for composite\noperators, regularized on the lattice, by extending the coordinate space\n(X-space) scheme proposed some years ago. In this scheme, Green's functions of\nproducts of gauge-invariant operators located at different spacetime points are\nconsidered. Due to the gauge-invariant nature of GIRS, gauge fixing is not\nneeded in the lattice simulations. Also, when operator mixing occurs, the\ngauge-variant operators (BRST variations and operators which vanish by the\nequations of motion) can be safely excluded from the renormalization process.\n  We propose a number of variants of GIRS, including integration over time\nslices of the operator insertion point in a Green's function, which may lead to\nreduced statistical noise in lattice simulations. We employ these variants in\nthe renormalization of fermion bilinear operators and the study of mixing\nbetween the gluon and quark energy-momentum tensor operators. We extract the\none-loop conversion factors relating the nonperturbative renormalization\nfactors in different versions of GIRS to the reference scheme of $\\overline{\\rm\nMS}$.",
        "positive": "3d N=4 Super-Yang-Mills on a Lattice: In this paper we explore a new approach to studying three-dimensional N=4\nsuper-Yang-Mills on a lattice. Our strategy is to complexify the\nDonaldson-Witten twist of four-dimensional N=2 super-Yang-Mills to make it\namenable to a lattice formulation and we find that lattice gauge invariance\nforces the model to live in at most three dimensions. We analyze the\nrenormalization of the lattice theory and show that uncomplexified\nthree-dimensional N=4 super-Yang-Mills can be reached in the continuum limit by\nsupplementing the lattice action with appropriate mass terms."
    },
    {
        "anchor": "Chirally Extended Quantum Chromodynamics: We propose an extended Quantum Chromodynamics (XQCD) Lagrangian in which the\nfermions are coupled to elementary scalar %$\\sigma$ and $\\pi$ fields through a\nYukawa coupling which preserves chiral invariance. Our principle motivation is\nto find a new lattice formulation for QCD which avoids the source of critical\nslowing down usually encountered as the bare quark mass is tuned to the chiral\nlimit. The phase diagram and the weak coupling limit for XQCD are studied. They\nsuggest a conjecture that the continuum limit of XQCD is the same as the\ncontinuum limit of conventional lattice formulation of QCD. As examples of such\nuniversality, we present the large N solutions of two prototype models for\nXQCD, in which the mass of the spurious pion and sigma resonance go to infinity\nwith the cut-off. Even if the universality conjecture turns out to be false, we\nbelieve that XQCD will still be useful as a low energy effective action for QCD\nphenomenology on the lattice. Numerical simulations are recommended to further\ninvestigate the possible benefits of XQCD in extracting QCD predictions.\nPostscript files for figures are attached. Search for strings \"fig11.ps\",\n\"fig22.ps\", \"fig33.ps\".",
        "positive": "Time Dependence of Nucleon Correlation Functions in Chiral Perturbation\n  Theory: We consider corrections to nucleon correlation functions arising from times\nthat are far from the asymptotic limit. For such times, the single nucleon\nstate is contaminated by the pion-nucleon and pion-delta continuum. We use\nheavy baryon chiral perturbation theory to derive the spectral representation\nof the nucleon two-point function. Finite time corrections to the axial current\ncorrelation function are also derived. Pion-nucleon excited state contributions\ndrive the axial correlator upward, while contributions from the interference of\npion-delta and pion-nucleon states drive the axial correlator downward. Our\nresults can be compared qualitatively to optimized nucleon correlators\ncalculated in lattice QCD, because the chiral corrections characterize only\nlow-energy excitations above the ground state. We show that improved nucleon\noperators can lead to an underestimation of the nucleon axial charge."
    },
    {
        "anchor": "Geometrical clusterization of Polyakov loops in SU(2) lattice\n  gluodynamics: The liquid droplet formula is applied to an analysis of the properties of\ngeometrical (anti)clusters formed in SU(2) gluodynamics by the Polyakov loops\nof the same sign. Using this approach, we explain the phase transition in SU(2)\ngluodynamics as a transition between two liquids during which one of the liquid\ndroplets (the largest cluster of a certain Polyakov loop sign) experiences a\ncondensation, while the droplet of another liquid (the next to the largest\ncluster of the opposite sign of Polyakov loop) evaporates. The clusters of\nsmaller sizes form two accompanying gases, which behave oppositely to their\nliquids. The liquid droplet formula is used to analyze the size distributions\nof the gaseous (anti)clusters. The fit of these distributions allows us to\nextract the temperature dependence of surface tension and the value of Fisher\ntopological exponent $\\tau$ for both kinds of gaseous clusters. It is shown\nthat the surface tension coeficient of gaseous (anti)clusters can serve as an\norder parameter of the deconfinement phase transition in SU(2) gluodynamics.\nThe Fisher topological exponent $\\tau$ of clusters and anticlusters is found to\nhave the same value $1.806 \\pm 0.008$. This value disagrees with the famous\nFisher droplet model, but it agrees well with an exactly solvable model of the\nnuclear liquid-gas phase transition. This finding may evidence for the fact\nthat the SU(2) gluodynamics and this exactly solvable model of nuclear\nliquid-gas phase transition are in the same universality class.",
        "positive": "The negative-parity spin-1/2 $\u039b$ baryon spectrum from lattice QCD\n  and effective theory: The spectrum of the negative-parity spin-1/2 $\\Lambda$ baryons is studied\nusing lattice QCD and hadronic effective theory in a unitarized coupled-channel\nframework. A direct comparison between the two approaches is possible by\nconsidering the hadronic effective theory in a finite volume and with hadron\nmasses and mesonic decay constants that correspond to the situation studied on\nthe lattice. Comparing the energy level spectrum and $SU(3)$ flavor\ndecompositions of the individual states, it is found that the lowest two states\nextracted from lattice QCD can be identified with one of the two\n$\\Lambda(1405)$-poles and the $\\Lambda(1670)$ resonance. The quark mass\ndependences of these two lattice QCD levels are in good agreement with their\neffective theory counterparts. However, as current lattice QCD studies still\nrely on three-quark operators to generate the physical states, clear signals\ncorresponding to the meson-baryon scattering states, that appear in the finite\nvolume effective theory calculation, are not yet seen."
    },
    {
        "anchor": "A solution for infinite variance problem of fermionic observables: Fermionic Monte Carlo calculations with continuous auxiliary fields often\nencounter infinite variance problem from fermionic observables. This issue\nrenders the estimation of observables unreliable, even with an infinite number\nof samples. In this work, we show that the infinite variance problem stems from\nthe fermionic determinant. Also, we propose an approach to address this problem\nby employing a reweighting method that utilizes the distribution from an extra\ntime-slice. Two strategies to compute the reweighting factor are explored: one\ninvolves truncating and analytically calculating the reweighting factor, while\nthe other employs a secondary Monte Carlo estimation. With Hubbard model as a\ntestbed, we demonstrate that utilizing the sub-Monte Carlo estimation, coupled\nwith an unbiased estimator, offers a solution that effectively mitigates the\ninfinite variance problem at a minimal additional cost.",
        "positive": "Classical U(1) Lattice Gauge Theory in D=2: Under the hypothesis of no topological structure below a certain scale, we\nprove that any U(1) lattice configuration corresponds to a classical U(1) gauge\nfield with zero local field strength; i.e. any local representative of the\npullback connection one-form is a pure gauge and the local curvature two-form\nis thus identical zero. The topological information is completely carried by\nthe chart transitions. To each such U(1) lattice configuration we assign a\nChern number, which generally depends on the reconstruction of the bundle and\nis only unique under certain restrictions."
    },
    {
        "anchor": "Analytic calculation of the 1-loop effective action for the\n  O(N+1)-symmetric 2-dimensional nonlinear sigma-model: Polyakov's calculation of the effective action for the 2d nonlinear\nsigma-Model is generalized by purely analytic means to include contributions\nwhich are not UV-divergent and which depend on the choice of block spin. An\nanalytic approximation to the background field which determines the classical\nperfect action is given, and approximations to the 1-loop correction are found.\nThe results should be useful for numerical simulations.",
        "positive": "Axial U(1) symmetry at high temperatures in $N_f=2+1$ lattice QCD with\n  chiral fermions: We study the $U(1)_A$ anomaly in the high-temperature phase of $N_f=2+1$\nlattice QCD with chiral fermions. Gauge ensembles are generated with M\\\"obius\ndomain-wall (MDW) fermions, and in the measurements the determinant is\nreweighted to that of overlap fermions. We report the results for the overlap\nDirac spectrum, $U(1)_A$ susceptibility, and topological susceptibility at\n$T=204$ and $175$ MeV."
    },
    {
        "anchor": "Partial deconfinement in QCD at $N=3$ and $N=\\infty$: We describe how the general mechanism of partial deconfinement applies to\nlarge-$N$ QCD and the partially-deconfined phase inevitably appears between\ncompletely-confined and completely-deconfined phases. Furthermore, we propose\nhow the partial deconfinement can be observed in the real-world QCD with SU(3)\ngauge group. We propose the relationship between the behaviors of the Polyakov\nloop and other quantities. We test our proposal against lattice simulation data\nand find a nontrivial matching.",
        "positive": "Broken Symmetry and Fractionalized Flux Strings in a Staggered U(1) Pure\n  Gauge Theory: Inspired by self-adjoint extensions of the electric field operator in the\nHamiltonian formalism, we extend the Wilsonian framework of Abelian lattice\ngauge theory by introducing a modified action parameterized by an angle\n$\\alpha$, where the ordinary Wilson theory corresponds to $\\alpha=0$. Choosing\ninstead $\\alpha=\\pi$ (the \"staggered\" case) gives the only other theory in the\nfamily which preserves all symmetries of the original model at the microscopic\nlevel. We study the case of $3D$ $\\mathrm{U}(1)$ pure gauge theory, simulating\nthe staggered case of this model numerically in its dual formulation. We find\nevidence of a continuum limit with a spontaneously broken $\\mathbb{Z}_2$\nsingle-site translational symmetry, in contrast to the ordinary theory.\nMoreover, the confining string fractionalizes into multiple strands which\nseparate spatial regions in distinct ground states of the broken symmetry."
    },
    {
        "anchor": "A Quenched Exploration of Heavy Quark Moments and their Perturbative\n  Expansion: The parametric error on the QCD-coupling can be a dominant source of\nuncertainty in several important observables. One way to extract the coupling\nis to compare high order perturbative computations with lattice evaluated\nmoments of heavy quark two-point functions. The truncation of the perturbative\nseries is a sizable systematic uncertainty that needs to be under control. In\nthis contribution we give an update on our study arXiv:hep-lat/2203.07936v1 on\nthis issue. We measure pseudo-scalar two-point functions in volumes of $L=2$ fm\nwith twisted-mass Wilson fermions in the quenched approximation. We use full\ntwist, the non-perturbative clover term and lattice spacings down to $a=0.010$\nfm to tame the large discretization effects. Our results show that both the\ncontinuum extrapolations and the extrapolation of the $\\Lambda$-parameter to\nthe asymptotic perturbative region are very challenging.",
        "positive": "Space-time symmetric qubit regularization of the asymptotically free\n  two-dimensional O(4) model: We explore if space-time symmetric lattice field theory models with a finite\nHilbert space per lattice site can reproduce asymptotic freedom in the\ntwo-dimensional $O(4)$ model. We focus on a simple class of such models with a\nfive dimensional local Hilbert space. We demonstrate how even the simplest\nmodel reproduces asymptotic freedom within the D-theory formalism but at the\ncost of increasing the size of the Hilbert space through coupling several\nlayers of a two-dimensional lattice. We then argue that qubit regularization\ncan be viewed as an effective field theory (EFT) even if the continuum limit\ncannot be reached, as long as we can tune the model close enough to the\ncontinuum limit where perturbation theory, or other analytical techniques,\nbecome viable. We construct a simple lattice model on a single layer with a\nfour dimensional local Hilbert space that acts like an excellent EFT of the\noriginal theory."
    },
    {
        "anchor": "The PHMC algorithm for simulations of dynamical fermions: II -\n  Performance analysis: We compare the performance of the PHMC algorithm with the one of the HMC\nalgorithm in practical simulations of lattice QCD. We show that the PHMC\nalgorithm can lead to an acceleration of numerical simulations. It is\ndemonstrated that the PHMC algorithm generates configurations carrying small\nisolated eigenvalues of the lattice Dirac operator and hence leads to a\nsampling of configuration space that is different from that of the HMC\nalgorithm.",
        "positive": "Scattering processes and resonances from lattice QCD: The vast majority of hadrons observed in nature are not stable under the\nstrong interaction, rather they are resonances whose existence is deduced from\nenhancements in the energy dependence of scattering amplitudes. The study of\nhadron resonances offers a window into the workings of quantum chromodynamics\n(QCD) in the low-energy non-perturbative region, and in addition, many probes\nof the limits of the electroweak sector of the Standard Model consider\nprocesses which feature hadron resonances. From a theoretical standpoint, this\nis a challenging field: the same dynamics that binds quarks and gluons into\nhadron resonances also controls their decay into lighter hadrons, so a complete\napproach to QCD is required. Presently, lattice QCD is the only available tool\nthat provides the required non-perturbative evaluation of hadron observables.\nIn this article, we review progress in the study of few-hadron reactions in\nwhich resonances and bound-states appear using lattice QCD techniques. We\ndescribe the leading approach which takes advantage of the periodic finite\nspatial volume used in lattice QCD calculations to extract scattering\namplitudes from the discrete spectrum of QCD eigenstates in a box. We explain\nhow from explicit lattice QCD calculations, one can rigorously garner\ninformation about a variety of resonance properties, including their masses,\nwidths, decay couplings, and form factors. The challenges which currently limit\nthe field are discussed along with the steps being taken to resolve them."
    },
    {
        "anchor": "The Hadronic Spectrum and Confined Phase in (1+1)-Dimensional Massive\n  Yang-Mills Theory: Massive Yang-Mills theory is known to be renormalizable in 1+1 dimensions.\nThe gluon mass is introduced by coupling the gauge field to an SU(N) principal\nchiral nonlinear sigma model. The proof of renormalizability relies on the\nasymptotic freedom of the sigma model. However, renormalization forces the\ngluon mass to infinity. The continuum theory is in a confined phase rather than\na Higgs phase. The physical excitations of the system are hadron-like bound\nstates of sigma model particles. We calculate the massive spectrum of\nmeson-like bound states analytically, using the exact S-matrix of the sigma\nmodel. The baryon-like spectrum can be found in principle by solving a quantum\nmechanical N-body problem. We remark on the evidence for the confined phase\nfound for SU(2) in recent lattice simulations by Gongyo and Zwanziger. Their\nsimulations show evidence for a Higgs-like phase which seems to disappear with\nincreasing volume, finding agreement with our analysis in the continuum.",
        "positive": "Lattice Study of the Massive Schwinger Model with $\u03b8$ Term under\n  L\u00fcscher's \"Admissibility\" Condition: L\\\"uscher's ``admissibility'' condition on the gauge field space plays an\nessential role in constructing lattice gauge theories which has exact chiral\nsymmetries. We apply the gauge action proposed by L\\\"uscher with the\ndomain-wall fermion action to the numerical simulation of the massive Schwinger\nmodel. We find this action can generate configurations in each topological\nsector separately without any topology changes. By developing a new method to\nsum over different topological sectors, we calculate meson masses in\nnonzero-$\\theta$ vacuum."
    },
    {
        "anchor": "The determination of alpha_s(M_z) from perturbative analyses of\n  short-distance-sensitive lattice QCD observables revisited: The determination of alpha_s(M_Z) via perturbative analyses of\nshort-distance-sensitive lattice observables is revisited, incorporating new\nlattice data and performing a modified version of the original analysis. The\nanalysis employs two high-intrinsic-scale observables, log (W_11) and\nlog(W_12), and one lower-intrinsic-scale observable, log(W_12/u_0^6). We find\ngood consistency among the values extracted using the different observables and\na final result, alpha_s(M_Z)=0.1192(11), in excellent agreement with various\nrecent non-lattice determinations, as well as with the results of a similar,\nbut not identical, re-analysis by the HPQCD collaboration. The relation between\nthe two re-analyses is discussed, focussing on the complementarity of the two\napproaches.",
        "positive": "Lattice QCD study of $\u03c0\u03a3-\\bar{K}N$ scattering and the\n  $\u039b(1405)$ resonance: A lattice QCD computation of the coupled channel $\\pi\\Sigma-\\bar{K}N$\nscattering amplitudes in the $\\Lambda(1405)$ region is detailed. Results are\nobtained using a single ensemble of gauge field configurations with $N_{\\rm f}\n= 2+1$ dynamical quark flavors and $m_{\\pi} \\approx 200$ MeV and\n$m_K\\approx487$ MeV. Hermitian correlation matrices using both single baryon\nand meson-baryon interpolating operators for a variety of different total\nmomenta and irreducible representations are used. Several parametrizations of\nthe two-channel scattering $K$-matrix are utilized to obtain the scattering\namplitudes from the finite-volume spectrum. The amplitudes, continued to the\ncomplex energy plane, exhibit a virtual bound state below the $\\pi\\Sigma$\nthreshold and a resonance pole just below the $\\bar{K}N$ threshold."
    },
    {
        "anchor": "Color confinement and dual superconductivity: an update: The evidence for dual superconductivity as a mechanism for color confinement\nis reviewed. New developments are presented for full QCD, i.e. in the presence\nof dynamical quarks.",
        "positive": "Quark spin-orbit correlations in the proton: Generalized transverse momentum-dependent parton distributions (GTMDs)\nprovide a comprehensive framework for imaging the internal structure of the\nproton. In particular, by encoding the simultaneous distribution of quark\ntransverse positions and momenta, they allow one to directly access\nlongitudinal quark orbital angular momentum, and, moreover, to correlate it\nwith the quark helicity. The relevant GTMD is evaluated through a lattice\ncalculation of a proton matrix element of a quark bilocal operator (the\nseparation in which is Fourier conjugate to the quark momentum) featuring a\nmomentum transfer (which is Fourier conjugate to the quark position), as well\nas the Dirac structure appropriate for capturing the quark helicity. The\nweighting by quark transverse position requires a derivative with respect to\nmomentum transfer, which is obtained in unbiased fashion using a direct\nderivative method. The lattice calculation is performed directly at the\nphysical pion mass, using domain wall fermions to mitigate operator mixing\neffects. Both the Jaffe-Manohar as well as the Ji quark spin-orbit correlations\nare extracted, yielding evidence for a strong quark spin-orbit coupling in the\nproton."
    },
    {
        "anchor": "Topological Obstruction in Block-spin Transformations: Block-spin transformations from a fine lattice to a coarse one are shown to\ngive rise to a one-to-one correspondence between the zero-modes of the\nGinsparg-Wilson Dirac operators. The index is then preserved under the blocking\nprocess. Such a one-to-one correspondence is violated and the block-spin\ntransformation becomes necessarily ill-defined when the absolute value of the\nindex is larger than 2rN, where N is the number of the sites on the coarse\nlattice and r is the dimension of the gauge group representation of the fermion\nvariables.",
        "positive": "A high statistics study of the beta-function in the SU(2) lattice\n  thermodynamics: The beta-function is investigated on the lattice in SU(2) gluodynamics. It is\ndetermined within a scaling hypothesis while a lattice size fixed to be taken\ninto account. The functions calculated are compared with the ones obtained in\nthe continuum limit. Graphics processing units (GPU) are used as a computing\nplatform that allows gathering a huge amount of statistical data. Numerous\nbeta-functions are analyzed for various lattices. The coincidence of the\nlattice beta-function and the analytical expression in the region of the phase\ntransition is shown. New method for estimating a critical coupling value is\nproposed."
    },
    {
        "anchor": "Background field method in the gradient flow: The Yang--Mills gradient flow and its extension to the fermion field provide\na very general method to obtain renormalized observables in gauge theory. The\nmethod is applicable also with non-perturbative regularization such as lattice.\nThe gradient flow thus offers useful probes to study non-perturbative dynamics\nof gauge theory. In this work, aiming at possible simplification in\nperturbative calculations associated with the gradient flow, a modification of\nthe gauge-fixed version of the flow equation, which preserves gauge covariance\nunder the background gauge transformation, is proposed. This formulation allows\nfor example a very quick one-loop calculation of the small flow time expansion\nof a composite operator that is relevant to the construction of a lattice\nenergy--momentum tensor. Some details of the calculation, which have not been\ngiven elsewhere, are presented.",
        "positive": "Lattice calculations and the muon anomalous magnetic moment: Anomalous magnetic moment of the muon, $a_{\\mu}=(g_{\\mu}-2)/2$, is one of the\nmost precisely measured quantities in particle physics and it provides a\nstringent test of the Standard Model. The planned improvements of the\nexperimental precision at Fermilab and at J-PARC propel further reduction of\nthe theoretical uncertainty of $a_{\\mu}$. The hope is that the efforts on both\nsides will help resolve the current discrepancy between the experimental\nmeasurement of $a_{\\mu}$ and its theoretical prediction, and potentially gain\ninsight into new physics. The dominant sources of the uncertainty in the\ntheoretical prediction of $a_{\\mu}$ are the errors of the hadronic\ncontributions. I will discuss recent progress on determination of hadronic\ncontributions to $a_{\\mu}$ from lattice calculations."
    },
    {
        "anchor": "Relevant Gluonic Momentum for Confinement and Gauge-Invariant Formalism\n  with Dirac-mode Expansion: We investigate the relevant gluon-momentum region for confinement in lattice\nQCD on $16^4$ at $\\beta$=5.7, 5.8 and 6.0, based on the Fourier expansion. We\nfind that the string tension $\\sigma$, i.e., the confining force, is almost\nunchanged even after removing the high-momentum gluon component above 1.5GeV in\nthe Landau gauge. In fact, the confinement property originates from the\nlow-momentum gluon component below 1.5GeV, which is the upper limit to\ncontribute to $\\sigma$. In the relevant region, smaller gluon momentum\ncomponent is more important for confinement. Next, we develop a manifestly\ngauge-covariant expansion of the QCD operator such as the Wilson loop, using\nthe eigen-mode of the QCD Dirac operator $\\gamma^\\mu D^\\mu$. With this method,\nwe perform a direct analysis of the correlation between confinement and chiral\nsymmetry breaking in lattice QCD on $6^4$ at $\\beta$=5.6. As a remarkable fact,\nthe confinement force is almost unchanged even after removing the low-lying\nDirac modes, which are responsible to chiral symmetry breaking. This indicates\nthat one-to-one correspondence does not hold for between confinement and chiral\nsymmetry breaking in QCD.",
        "positive": "Lattice quantum chromodynamics at large isospin density: 6144 pions in a\n  box: We present an algorithm to compute correlation functions for systems with the\nquantum numbers of many identical mesons from lattice quantum chromodynamics\n(QCD). The algorithm is numerically stable and allows for the computation of\n$n$-pion correlation functions for $n \\in \\{ 1, \\dots, N\\}$ using a single $N\n\\times N$ matrix decomposition, improving on previous algorithms. We apply the\nalgorithm to calculations of correlation functions with up to 6144 $\\pi^+$s\nusing two ensembles of gauge field configurations generated with quark masses\ncorresponding to a pion mass $m_\\pi = 170$ MeV and spacetime volumes of\n$(4.4^3\\times 8.8)\\ {\\rm fm}^4$ and $(5.8^3\\times 11.6)\\ {\\rm fm}^4$. We also\ndiscuss statistical techniques for the analysis of such systems, in which the\ncorrelation functions vary over many orders of magnitude. In particular, we\nobserve that the many-pion correlation functions are well approximated by\nlog-normal distributions, allowing the extraction of the energies of these\nsystems. Using these energies, the large-isospin-density, zero-baryon-density\nregion of the QCD phase diagram is explored. A peak is observed in the energy\ndensity at an isospin chemical potential $\\mu_I\\sim 1.5 m_\\pi$, signalling the\ntransition into a Bose-Einstein condensed phase. The isentropic speed of sound\nin the medium is seen to exceed the ideal-gas (conformal) limit ($c_s^2\\leq\n1/3$) over a wide range of chemical potential before falling towards the\nasymptotic expectation at $\\mu_I\\sim 15 m_\\pi$. These, and other thermodynamic\nobservables, indicate that the isospin chemical potential must be large for the\nsystem to be well described by an ideal gas or perturbative QCD."
    },
    {
        "anchor": "Borici-Creutz fermions on 2-dim lattice: Minimally doubled fermion proposed by Creutz and Borici is a promising chiral\nfermion formulation on lattice. In this work, we present excited state mass\nspectroscopy for the meson bound states in Gross-Neveu model using\nBorici-Creutz fermion. We also evaluate the effective fermion mass as a\nfunction of coupling constant which shows a chiral phase transition at strong\ncoupling. The lowest lying meson in 2-dimensional QED is also obtained using\nBorici-Creutz fermion.",
        "positive": "Meson-Nucleon Scattering Amplitudes from Lattice QCD: Lattice QCD calculations of resonant meson-meson scattering amplitudes have\nimproved significantly due to algorithmic and computational advances. However,\nprogress in meson-nucleon scattering has been slower due to difficulties in\ncomputing the necessary correlation functions, the exponential signal-to-noise\nproblem, and the finite-volume treatment of scattering with fermions.\nNonetheless, first benchmark calculations have now been performed. The status\nof lattice QCD calculations of meson-nucleon scattering amplitudes is reviewed\ntogether with comments on future prospects."
    },
    {
        "anchor": "Leibniz rule and exact supersymmetry on lattice: a case of\n  supersymmetrical quantum mechanics: We propose a new formulation of lattice theory. It is given by a matrix form\nand suitable for satisfying Leibniz rule on lattice. The theory may be\ninterpreted as a multi-flavor system. By realizing the difference operator as a\ncommutator, we may obtain exact supersymmetric theories on lattice explicitly.\nSome problems such as locality and single flavor reduction are also commented.",
        "positive": "Fortran MPI Checkerboard Code for SU(3) Lattice Gauge Theory I: We document Fortran MPI checkerboard code for Markov Chain Monte Carlo\nsimulations of pure SU(3) lattice gauge theory with the Wilson action on a\nD-dimensional double-layered torus. This includes the usual torus with periodic\nboundary conditions as an optional case. We use Cabibbo-Marinari heatbath\ncheckerboard updating. Parallelization on sublattices is implemented in all D\ndirections and can be restricted to less than D directions. The parallelization\ntechniques of this paper can be used for any model with interactions of link\nvariables defined on plaquettes."
    },
    {
        "anchor": "Instanton and Meron Physics in Lattice QCD: Lattice field theory provides a quantitative tool to study the role of\nnonperturbative semiclassical configurations in QCD. This talk briefly reviews\nour present understanding of the role of instantons in QCD and describes in\ndetail new developments in the study of merons on the lattice.",
        "positive": "Chiral condensate from the Banks-Casher relation: We report on our ongoing project of determining the chiral condensate of\ntwo-flavor QCD from the Banks-Casher relation. We compute the mode number of\nthe O(a)-improved Wilson-Dirac operator for several values of \\Lambda, and we\ndiscuss different fitting strategies to extract the chiral condensate from its\nmass and \\Lambda dependence. Our preliminary results haven been obtained at two\ndifferent lattice spacings by using CLS-configurations."
    },
    {
        "anchor": "2D Lorentzian Gravity as 2D Euclidean Gravity with Ising Spins: We suggest a generalization of the dynamical triangulation approach to\nquantum gravity with both timelike and spacelike edges, which can serve as a\ntoy model for quantum gravity in the Lorentz sector in two dimensions. It is\npossible to consider the model in a purely Lorentzian sector or to relax this\nconstraint and allow local signature changing moves. We show that, with\nsuitable conventions, the model is equivalent to an Ising model coupled to 2D\nEuclidean quantum gravity and conduct a preliminary numerical simulation of the\nLorentz sector.",
        "positive": "Static magnetic susceptibility in finite-density SU(2) lattice gauge\n  theory: We study static magnetic susceptibility $\\chi(T, \\mu)$ in $SU(2)$ lattice\ngauge theory with $N_f = 2$ light flavours of dynamical fermions at finite\nchemical potential $\\mu$. Using linear response theory we find that $SU(2)$\ngauge theory exhibits paramagnetic behavior in both the high-temperature\ndeconfined regime and the low-temperature confining regime. Paramagnetic\nresponse becomes stronger at higher temperatures and larger values of the\nchemical potential. For our range of temperatures $0.727 \\leq T/T_c \\leq 2.67$,\nthe first coefficient of the expansion of $\\chi(T, \\mu)$ in even powers of\n$\\mu/T$ around $\\mu=0$ is close to that of free quarks and lies in the range\n$(2 \\ldots 5) \\cdot 10^{-3}$. The strongest paramagnetic response is found in\nthe diquark condensation phase at $\\mu > m_{\\pi}/2$."
    },
    {
        "anchor": "Quantum Link Models with Many Rishon Flavors and with Many Colors: Quantum link models are a novel formulation of gauge theories in terms of\ndiscrete degrees of freedom. These degrees of freedom are described by quantum\noperators acting in a finite-dimensional Hilbert space. We show that for\ncertain representations of the operator algebra, the usual Yang-Mills action is\nrecovered in the continuum limit. The quantum operators can be expressed as\nbilinears of fermionic creation and annihilation operators called rishons.\nUsing the rishon representation the quantum link Hamiltonian can be expressed\nentirely in terms of color-neutral operators. This allows us to study the large\nN_c limit of this model. In the 't Hooft limit we find an area law for the\nWilson loop and a mass gap. Furthermore, the strong coupling expansion is a\ntopological expansion in which graphs with handles and boundaries are\nsuppressed.",
        "positive": "Machine learning spectral functions in lattice QCD: We study the inverse problem of reconstructing spectral functions from\nEuclidean correlation functions via machine learning. We propose a novel neural\nnetwork, SVAE, which is based on the variational autoencoder (VAE) and can be\nnaturally applied to the inverse problem. The prominent feature of the SVAE is\nthat a Shannon-Jaynes entropy term having the ground truth values of spectral\nfunctions as prior information is included in the loss function to be\nminimized. We train the network with general spectral functions produced from a\nGaussian mixture model. As a test, we use correlators generated from four\ndifferent types of physically motivated spectral functions made of one\nresonance peak, a continuum term and perturbative spectral function obtained\nusing non-relativistic QCD. From the mock data test we find that the SVAE in\nmost cases is comparable to the maximum entropy method (MEM) in the quality of\nreconstructing spectral functions and even outperforms the MEM in the case\nwhere the spectral function has sharp peaks with insufficient number of data\npoints in the correlator. By applying to temporal correlation functions of\ncharmonium in the pseudoscalar channel obtained in the quenched lattice QCD at\n0.75 $T_c$ on $128^3\\times96$ lattices and $1.5$ $T_c$ on $128^3\\times48$\nlattices, we find that the resonance peak of $\\eta_c$ extracted from both the\nSVAE and MEM has a substantial dependence on the number of points in the\ntemporal direction ($N_\\tau$) adopted in the lattice simulation and $N_\\tau$\nlarger than 48 is needed to resolve the fate of $\\eta_c$ at 1.5 $T_c$."
    },
    {
        "anchor": "New Algorithm of the Finite Lattice Method for the High-temperature\n  Expansion of the Ising Model in Three Dimensions: We propose a new algorithm of the finite lattice method to generate the\nhigh-temperature series for the Ising model in three dimensions. It enables us\nto extend the series for the free energy of the simple cubic lattice from the\nprevious series of 26th order to 46th order in the inverse temperature. The\nobtained series give the estimate of the critical exponent for the specific\nheat in high precision.",
        "positive": "First experiences with HMC for dynamical overlap fermions: We describe an HMC algorithm for dynamical overlap fermions which makes use\nof their good chiral properties. We test the algorithm in the Schwinger model.\nTopological sectors are readily changed even in the massless case."
    },
    {
        "anchor": "Electromagnetic properties of hadrons with two flavors of dynamical\n  domain wall fermions: We present the determination of the light quark masses using electromagnetic\nsplittings of pions and kaons. The meson masses are calculated on $SU(3)\\times\nU(1)$ gauge configurations, where SU(3) gauge fields include sea quark effects\nof two degenerate flavors and the U(1) gauge fields are incorporated in\nnon-compact form. Possible sources of systematic uncertainty are discussed.",
        "positive": "Chiral behavior of baryon magnetic moments: The utility of chiral effective field theory, constructed in a manner in\nwhich loop contributions are suppressed as one moves outside the power-counting\nregime, is explored for baryon magnetic moments. Opportunities for the study of\nsignificant chiral curvature in valence and full QCD and the nontrivial\nbehavior of strange- and light-quark contributions to the magnetic moment of\nthe Lambda baryon are highlighted."
    },
    {
        "anchor": "Study of the running coupling constant in 10-flavor QCD with the\n  Schroedinger functional method: The electroweak gauge symmetry is allowed to be spontaneously broken by the\nstrongly interacting vector-like gauge dynamics. When the gauge coupling of a\ntheory runs slowly in a wide range of energy scale, the theory is extremely\ninteresting. This may open up the possibility that the origin of all masses may\nbe traced back to the gauge theory. We use the SF method to determine the scale\ndependence of the gauge coupling of 10-flavor QCD. Preliminary results are\nreported.",
        "positive": "Correlation Function in Ising Models: We simulated the fourier transform of the correlation function of the Ising\nmodel in two and three dimensions using a single cluster algorithm with\nimproved estimators. The simulations are in agreement with series expansion and\nthe available exact results in $d=2$, which shows, that the cluster algorithm\ncan succesfully be applied for correlations. We show as a further result that\nour data do not support a hypothesis of Fisher that in any $d=2$ lattice the\nfourier transform of the correlation function depends on the lattice generating\nfunction only. In $d=3$ our simulation are again in agreement with the results\nfrom the series expansion, except for the amplitudes $f_{\\pm}$, where we find\n$f_+/f_-=2.06(1)$."
    },
    {
        "anchor": "Chiral behavior of kaon semileptonic form factors in lattice QCD with\n  exact chiral symmetry: We calculate the kaon semileptonic form factors in lattice QCD with three\nflavors of dynamical overlap quarks. Gauge ensembles are generated at pion\nmasses as low as 290 MeV and at a strange quark mass near its physical value.\nWe precisely calculate relevant meson correlators using the all-to-all quark\npropagator. Twisted boundary conditions and the reweighting technique are\nemployed to vary the momentum transfer and the strange quark mass. We discuss\nthe chiral behavior of the form factors by comparing with chiral perturbation\ntheory and experiments.",
        "positive": "In-medium heavy quarkonium from lattice NRQCD: We present the final results from a multi-year study of the in-medium\nspectral properties of heavy quarkonium bound states on the lattice. In this\nwork we combine high statistics $N_f=2+1$ ensembles from the HotQCD\ncollaboration with the effective theory NRQCD and improved Bayesian spectral\nreconstruction methods. We corroborate with high precision the hierarchical\nin-medium modification of quarkonium states with respect to their vacuum\nbinding energy and provide updated values on melting temperatures. In\nparticular we are able to understand previous disagreements between different\nBayesian methods as resulting from underestimated systematic uncertainties. The\nmain quantitative result is a robust determination of the in-medium mass shifts\nof quarkonium ground states, which we find are negative, consistent with the\nbehavior observed in strongly coupled pNRQCD potential based computations."
    },
    {
        "anchor": "Analytic Estimate of the Order Parameter for Monopole Condensation in\n  QCD: The disorder parameter $<\\mu>$ for the condensation of monopoles in QCD is\nestimated analytically in terms of gauge invariant field strength correlators.\nThe continuum limit is discussed.",
        "positive": "Instanton vacuum at finite density of quark matter: We study light quark interactions in the instanton liquid at finite\nquark/baryon number density analyzing chiral and diquark condensates and\ninvestigate the behaviors of quark dynamical mass and both condensates together\nwith instanton liquid density as a function of quark chemical potential. We\nconclude the quark impact (estimated in the tadpole approximation) on the\ninstanton liquid could shift color superconducting phase transition to higher\nvalues of the chemical potential bringing critical quark matter density to the\nvalues essentially higher than conventional nuclear one."
    },
    {
        "anchor": "Benchmarking and tuning the MILC code on clusters and supercomputers: Recently, we have benchmarked and tuned the MILC code on a number of\narchitectures including Intel Itanium and Pentium IV (PIV), dual-CPU Athlon,\nand the latest Compaq Alpha nodes. Results will be presented for many of these,\nand we shall discuss some simple code changes that can result in a very\ndramatic speedup of the KS conjugate gradient on processors with more advanced\nmemory systems such as PIV, IBM SP and Alpha.",
        "positive": "Finite Size Effects on the QCD Spectrum Revisited: We have continued our study of finite size effects in the QCD spectrum on\nlattices ranging in size from $8^3\\times 24$ to $16^3\\times24$. We have\nincreased our statistics for quark mass $am_q=0.025$ for the smallest lattice\nsize. In addition, we have studied quark mass 0.0125 for lattice sizes\n$12^3\\times24$ and $16^3\\times24$. These lattice sizes correspond to a box\n1.8--3.6 fm on a side when the rho mass at zero quark mass is used to set the\nscale. We discuss the nucleon to rho mass ratio at a smaller value of\n$m_\\pi/m_\\rho$ than previously studied with two dynamical flavors."
    },
    {
        "anchor": "Thermal imaginary part of a real-time static potential from classical\n  lattice gauge theory simulations: Recently, a finite-temperature real-time static potential has been introduced\nvia a Schr\\\"odinger-type equation satisfied by a certain heavy quarkonium\nGreen's function. Furthermore, it has been pointed out that it possesses an\nimaginary part, which induces a finite width for the tip of the quarkonium peak\nin the thermal dilepton production rate. The imaginary part originates from\nLandau-damping of low-frequency gauge fields, which are essentially classical\ndue to their high occupation number. Here we show how the imaginary part can be\nmeasured with classical lattice gauge theory simulations, accounting\nnon-perturbatively for the infrared sector of finite-temperature field theory.\nWe demonstrate that a non-vanishing imaginary part indeed exists\nnon-perturbatively; and that its value agrees semi-quantitatively with that\npredicted by Hard Loop resummed perturbation theory.",
        "positive": "The bulk transition of QCD with twelve flavors and the role of\n  improvement: We study the SU(3) gauge theory with Nf=12 flavors in the fundamental\nrepresentation by use of lattice simulations with staggered fermions. With a\nnon-improved action we observe a chiral zero-temperature (bulk) transition\nseparating a region at weak coupling, where chiral symmetry is realized, from a\nregion at strong coupling where chiral symmetry is broken. With improved\nactions, a more complicated pattern emerges, and in particular two first order\ntransitions in the chiral limit appear. We observe that at sufficiently strong\ncoupling the next-to-nearest neighbor terms of the improved lattice action are\nno longer irrelevant and can indeed modify the pattern observed without\nimprovement. Baryon number conservation can be realized in an unusual way,\nallowing for an otherwise prohibited oscillating term in the pseudoscalar\nchannel. We discuss the phenomenon by means of explicit examples borrowed from\nstatistical mechanics. Finally, these observations can also be useful when\nsimulating other strongly coupled systems on the lattice, such as graphene."
    },
    {
        "anchor": "Gauge-Fixed Fourier Acceleration: For an asymptotically free theory, a promising strategy for eliminating\nCritical Slowing Down (CSD) is na\\\"ive Fourier acceleration. This requires the\nintroduction of gauge-fixing into the action, in order to isolate the\nasymptotically decoupled Fourier modes. In this article, we present our\napproach and results from a gauge-fixed Fourier-accelerated hybrid Monte Carlo\nalgorithm, using an action that softly fixes the gauge links to Landau gauge.\nWe compare the autocorrelation times with those of the pure hybrid Monte Carlo\nalgorithm. We work on a small-volume lattice at weak coupling. We present\npreliminary results and obstacles from working with periodic boundary\nconditions, and then we present results from using fixed, equilibrated boundary\nlinks to avoid $\\mathbb{Z}_3$ and other topological barriers and to anticipate\napplying a similar acceleration to many small cells in a large,\nphysically-relevant lattice volume.",
        "positive": "Rigidity and percolation of center vortices: Effective action of center vortices in SU(2) lattice gauge theory is\ninvestigated by studying the correlation between the action density on their\nworldsheets and their geometric properties. It turns out that center vortices\nare rigid, however, their dynamics is more complicated than that of rigid\nrandom surfaces, since some coupling constants have nonstandard scaling\ndimensions. As a result, the properties of center vortices are almost\ncompletely determined by curvature-dependent effects. This, in turn, provides a\nqualitative explanation of vortex percolation."
    },
    {
        "anchor": "Continuum-limit scaling of overlap fermions as valence quarks: We present the results of a mixed action approach, employing dynamical\ntwisted mass fermions in the sea sector and overlap valence fermions, with the\naim of testing the continuum limit scaling behaviour of physical quantities,\ntaking the pion decay constant as an example. To render the computations\npractical, we impose for this purpose a fixed finite volume with lattice size\n$L\\approx1.3$ fm. We also briefly review the techniques we have used to deal\nwith overlap fermions.",
        "positive": "Pion and Rho Structure Functions from Lattice QCD: We calculate the lower moments of the deep-inelastic structure functions of\nthe pion and the rho meson on the lattice. Of particular interest to us are the\nspin-dependent structure functions of the rho. The calculations are done with\nWilson fermions and for three values of the quark mass, so that we can perform\nan extrapolation to the chiral limit."
    },
    {
        "anchor": "String breaking by light and strange quarks in QCD: The energy spectrum of a system containing a static quark anti-quark pair is\ncomputed for a wide range of source separations using lattice QCD with\n$N_\\mathrm{f}=2+1$ dynamical flavours. By employing a variational method with a\nbasis including operators resembling both the gluon string and systems of two\nseparated static mesons, the first three energy levels are determined up to and\nbeyond the distance where it is energetically favourable for the vacuum to\nscreen the static sources through light- or strange-quark pair creation,\nenabling both these screening phenomena to be observed. The separation\ndependence of the energy spectrum is reliably parameterised over this\nsaturation region with a simple model which can be used as input for subsequent\ninvestigations of quarkonia above threshold and heavy-light and heavy-strange\ncoupled-channel meson scattering.",
        "positive": "Quark confinement and gauge invariant monopoles in SU(2) YM: We give a short review of recently obtained results on a new lattice\nformulation of the non-linear change of variables which was once called the\nCho--Faddeev--Niemi decomposition in SU(2) Yang-Mills theory.\n  Based on this formulation, we proposed a new gauge-invariant definition of\nthe magnetic monopole current which guarantees the magnetic charge\nquantization. We also demonstrated the magnetic monopole dominance in the\nstring tension in SU(2) Yang-Mills theory on a lattice. Our formulation enables\none to reproduce in the gauge-invariant way remarkable results obtained so far\nonly in the Maximally Abelian gauge."
    },
    {
        "anchor": "Bound H-dibaryon in Flavor SU(3) Limit of Lattice QCD: The flavor-singlet H-dibaryon, which has strangeness -2 and baryon number 2,\nis studied by the approach recently developed for the baryon-baryon\ninteractions in lattice QCD. The flavor-singlet central potential is derived\nfrom the spatial and imaginary-time dependence of the Nambu-Bethe-Salpeter wave\nfunction measured in N_f=3 full QCD simulations with the lattice size of L = 2,\n3, 4 fm. The potential is found to be insensitive to the volume, and it leads\nto a bound H-dibaryon with the binding energy of 30 - 40 MeV for the\npseudo-scalar meson mass of 673 - 1015 MeV.",
        "positive": "Blasting through lattice calculations using CUDA: Modern graphics hardware is designed for highly parallel numerical tasks and\nprovides significant cost and performance benefits. Graphics hardware vendors\nare now making available development tools to support general purpose high\nperformance computing. Nvidia's CUDA platform, in particular, offers direct\naccess to graphics hardware through a programming language similar to C. Using\nthe CUDA platform we have implemented a Wilson-Dirac operator which runs at an\neffective 68 Gflops on the Tesla C870. The recently released GeForce GTX 280\nruns this same code at 92 Gflops, and we expect further improvement pending\ncode optimization."
    },
    {
        "anchor": "Green functions in graphene monolayer with Coulomb interactions taken\n  into account: We consider the low energy effective field model of graphene monolayer.\nCoulomb interactions are taken into account. The model is simulated numerically\nusing the lattice discretization with staggered fermions. The two point\nfermionic Green functions are calculated. We find that in the insulator phase\nthese Green functions almost do not depend on energy. This indicates that the\neffective field model (in its insulator phase) does not correspond to the real\ngraphene.",
        "positive": "RI/(S)MOM renormalizations of overlap quark bilinears with different\n  levels of hypercubic smearing: On configurations with 2+1-flavor dynamical domain-wall fermions, we\ncalculate the RI/(S)MOM renormalization constants (RC) of overlap quark\nbilinears. Hypercubic (HYP) smearing is used to construct the overlap Dirac\noperator. We investigate the possible effects of the smearing on discretization\nerrors in the RCs by varying the level of smearing from 0 to 1 and 2. The\nlattice is of size $32^3\\times64$ and with lattice spacing $1/a=2.383(9)$ GeV.\nThe RCs in the $\\overline{\\rm MS}$ scheme at 2 GeV are given at the end, with\nthe uncertainty of $Z_T$ reaching $\\le1$% for the tensor current. Results of\nthe renormalized quark masses and hadron matrix elements show that the\nrenormalization procedure suppresses the $\\sim$ 30% difference of the bare\nquantities with or without HYP smearing into the 3%-5% level."
    },
    {
        "anchor": "The Coupled Cluster Method in Hamiltonian Lattice Field Theory: SU(2)\n  Glueballs: The glueball spectrum within the Hamiltonian formulation of lattice gauge\ntheory (without fermions) is calculated for the gauge group SU(2) and for two\nspatial dimensions.\n  The Hilbert space of gauge-invariant functions of the gauge field is\ngenerated by its parallel-transporters on closed paths along the links of the\nspatial lattice. The coupled cluster method is used to determine the spectrum\nof the Kogut-Susskind Hamiltonian in a truncated basis. The quality of the\ndescription is studied by computing results from various truncations, lattice\nregularisations and with an improved Hamiltonian.\n  We find consistency for the mass ratio predictions within a scaling region\nwhere we obtain good agreement with standard lattice Monte Carlo results.",
        "positive": "Quenched lattice QCD at finite isospin density and related theories: We study quenched QCD at finite chemical potential, $\\mu_I$, for the third\ncomponent of isospin and quenched two-colour QCD at finite chemical potential,\n$\\mu$, for quark number. In contrast to the quenched approximation to QCD at\nfinite quark-number chemical potential, the quenched approximations to these\ntheories behave similarly to the full theories. The reason is that these\ntheories have real positive fermion determinants. In both of these theories\nthere is some critical chemical potential above which the charge coupled to the\nchemical potential is spontaneously broken. In each case, the transition\nappears to be second order. We study the scaling properties near the critical\npoint using scaling functions suggested by effective (chiral) Lagrangians and\nfind evidence for scaling with mean-field critical exponents in each case. The\nsubtleties associated with observing the critical scaling of these theories are\ndiscussed."
    },
    {
        "anchor": "Universality of a truncated sigma-model: Bosonic quantum field theories, even when regularized using a finite lattice,\npossess an infinite dimensional Hilbert space and, therefore, cannot be\nsimulated in quantum computers with a finite number of qubits. A truncation of\nthe Hilbert space is then needed and the physical results are obtained after a\ndouble limit: one to remove the truncation and another to remove the regulator\n(the continuum limit). A simpler alternative is to find a model with a finite\ndimensional Hilbert space belonging to the same universality class as the\ncontinuum model (a \"qubitization\"), so only the space continuum limit is\nrequired. A qubitization of the $1+1$ dimensional asymptotically free $O(3)$\nnonlinear $\\sigma$-model based on ideas of non-commutative geometry was\npreviously proposed arXiv:1903.06577 and, in this paper, we provide evidence\nthat it reproduces the physics of the $\\sigma$-model both in the infrared and\nthe ultraviolet regimes.",
        "positive": "Renormalisation of quark bilinears with Nf=2 Wilson fermions and\n  tree-level improved gauge action: We present results for the renormalisation constants of bilinear quark\noperators, using the Nf=2 twisted mass Wilson action at maximal twist (which\nguarantees automatic O(a) improvement) and the tree-level Symanzik improved\ngauge action. The scale-independent renormalisation constants are computed with\na new method, which makes use of both standard twisted mass and\nOsterwalder-Seiler fermions. Moreover, the results from an RI-MOM calculation\nare presented for both scale independent and scale dependent renormalisation\nconstants."
    },
    {
        "anchor": "Classification of sign-problem-free relativistic fermions on the basis\n  of the Majorana positivity: We classify the sign-problem-free relativistic fermion actions on the basis\nof the Majorana representation. In the Majorana representation, the\nsign-problem-free condition is given by the semi-positivity of a Pfaffian. We\nshow that the known sign-problem-free actions of the Dirac fermions, which are\nusually understood from the semi-positivity of a determinant, e.g., the action\nof quantum chromodynamics with nonzero chiral chemical potential or nonzero\nisospin chemical potential, can also be understood from the semi-positivity of\na Pfaffian. We also derive new classes of the sign-problem-free relativistic\nfermion actions with Majorana-type source terms.",
        "positive": "Gibbs sampling of complex valued distributions: A new technique is explored for the Monte Carlo sampling of complex-valued\ndistributions. The method is based on a heat bath approach where the\nconditional probability is replaced by a positive representation of it on the\ncomplex plane. Efficient ways to construct such representations are also\nintroduced. The performance of the algorithm is tested on small and large\nlattices with a $\\lambda\\phi^4$ theory with quadratic nearest-neighbor complex\ncoupling. The method works for moderate complex couplings, reproducing\nreweighting and complex Langevin results and fulfilling various Schwinger-Dyson\nrelations."
    },
    {
        "anchor": "Combining the color structures and intersection points of thick center\n  vortices and low-lying Dirac modes: We investigate several examples of Yang-Mills gauge configurations containing\ncenter vortex structures, including intersection points between vortices and\nnontrivial color structures residing on the vortex world-surfaces. Various\ntopological charge contributions of the color structures and intersection\npoints are studied in these configurations. Low-lying eigenmodes of the\n(overlap) Dirac operator in the presence of these vortex backgrounds are\nanalyzed. The results indicate characteristic properties for spontaneous chiral\nsymmetry breaking.",
        "positive": "Unpolarized gluon distribution in the nucleon from lattice quantum\n  chromodynamics: In this study, we present a determination of the unpolarized gluon Ioffe-time\ndistribution in the nucleon from a first principles lattice quantum\nchromodynamics calculation. We carry out the lattice calculation on a\n$32^3\\times 64$ ensemble with a pion mass of $358$ MeV and lattice spacing of\n$0.094$ fm. We construct the nucleon interpolating fields using the\ndistillation technique, flow the gauge fields using the gradient flow, and\nsolve the summed generalized eigenvalue problem to determine the glounic matrix\nelements. Combining these techniques allows us to provide a statistically\nwell-controlled Ioffe-time distribution and unpolarized gluon PDF. We obtain\nthe flow time independent reduced Ioffe-time pseudo-distribution, and calculate\nthe light-cone Ioffe-time distribution and unpolarized gluon distribution\nfunction in the $\\overline{\\rm MS}$ scheme at $\\mu = 2$ GeV, neglecting the\nmixing of the gluon operator with the quark singlet sector. Finally, we compare\nour results to phenomenological determinations."
    },
    {
        "anchor": "The topological susceptibility of SU(3) gauge theory near T_c: We compute the topological susceptibility chi_t in SU(3) lattice gauge theory\nusing fermionic methods based on the Atiyah-Singer index theorem. Near the\nphase transition we find a smooth crossover behavior for chi_t with values\ndecreasing from (191(5) MeV)^4 to (100(5) MeV)^4 as we increase the temperature\nfrom 0.88 T_c to 1.31 T_c, showing that topological excitations exist far above\nT_c. Our study is the first large scale analysis of the topological\nsusceptibility at high temperature based on the index theorem and the results\nagree well with field theoretical methods.",
        "positive": "Three-body resonances in the $\\varphi^4$ theory: We study the properties of three-body resonances using a lattice complex\nscalar $\\varphi^4$ theory with two scalars, with parameters chosen such that\none heavy particle can decay into three light ones. We determine the two- and\nthree-body spectra for several lattice volumes using variational techniques,\nand then analyze them with two versions of the three-particle finite-volume\nformalism: the Relativistic Field Theory approach and the Finite-Volume\nUnitarity approach. We find that both methods provide an equivalent description\nof the energy levels, and we are able to fit the spectra using simple\nparametrizations of the scattering quantities. By solving the integral\nequations of the corresponding three-particle formalisms, we determine the pole\nposition of the resonance in the complex energy-plane and thereby its mass and\nwidth. We find very good agreement between the two methods at different values\nof the coupling of the theory."
    },
    {
        "anchor": "Renormalization of CP-Violating Pure Gauge Operators in Perturbative QCD\n  Using the Gradient Flow: We use the Yang-Mills gradient flow to study the mixing of CP-violating pure\ngauge operators in continuum QCD with special attention to Weinberg's d=6\npurely gluonic operator. The gradient flow allows for a relatively clear\nderivation of the Wilson coefficients of the CP-violating effective\nHamiltonian. This calculation is the first step towards a high-energy matching\nof matrix elements involving the CP-violating operators between the\nperturbative and lattice regimes.",
        "positive": "Study of two color QCD on large lattices: We study two colors lattice QCD (QC$_2$D) with two flavors of staggered\nfermions on $40^4$ and $32^4$ lattices with lattice spacing $a =0.048$~fm in\nthe wide range of the quark chemical potential $\\mu_q$. Our focus is on the\nconfinement-deconfinement transition in this theory. Thus we compute the string\ntension from the Wilson loops and the static quark free energy from the\nPolyakov loops. We find that the deconfinement transition found earlier in the\nrange $\\mu_q \\approx 800 - 1000$ MeV is shifted to higher values. This shift is\nattributed to decreasing of the lattice spacing used in our simulations in\ncomparison with the earlier study."
    },
    {
        "anchor": "What is chiral susceptibility probing?: In the early days of QCD, the axial $U(1)$ anomaly was considered as a\ntrigger for the breaking of the $SU(2)_L\\times SU(2)_R$ symmetry through\ntopological excitations of gluon fields. However, it has been a challenge for\nlattice QCD to quantify the effect. In this work, we simulate QCD at high\ntemperatures with chiral fermions. The exact chiral symmetry enables us to\nseparate the contribution from the axial $U(1)$ breaking from others among the\nsusceptibilities in the scalar and pseudoscalar channels. Our result in\ntwo-flavor QCD indicates that the chiral susceptibility, which is\nconventionally used as a probe for $SU(2)_L\\times SU(2)_R$ breaking, is\nactually dominated by the axial $U(1)$ breaking at temperatures $T\\ge 165$ MeV.",
        "positive": "Scalar Glueball Decay: We evaluate the coupling constant for the lightest scalar glueball to decay\nto pseudoscalar meson pairs. The calculation is done in the valence\napproximation on a $16^3 \\times 24$ lattice at $\\beta = 5.70$ for two different\nvalues of pseudoscalar meson mass."
    },
    {
        "anchor": "Conformality in twelve-flavour QCD: The spectrum of twelve-flavor QCD has been studied in details by the LatKMI\ncollaboration. In this proceeding we present our updated results for the\nspectrum obtained with the HISQ action at two lattice spacings, several volumes\nand fermion masses. In particular, we emphasize the existence of a\nflavor-singlet scalar state parametrically light with respect to the rest of\nthe spectrum, first reported in our paper. This feature is expected to be\npresent for theories in the conformal window, but the lattice calculation of\nsuch a state is difficult and requires noise-reduction techniques together with\nlarge statistics, in order to evaluate disconnected diagrams. Being able to\nprovide a robust observed connection between a light flavor-singlet scalar and\n(near-)conformality is an important step towards observing a light composite\nHiggs boson in walking technicolor theories on the lattice. We also show\nupdated results for the mass anomalous dimension $\\gamma_m$ obtained from\nvarious spectral quantities, including the string tension, under the assumption\nthat the theory is inside the conformal window.",
        "positive": "Lattice calculation of $\u03ba$ meson: We study the $\\kappa$ meson in 2+1 flavor QCD with sufficiently light $u/d$\nquarks. Using numerical simulation we measure the point-to-point $\\kappa$\ncorrelators in the \"Asqtad\" improved staggered fermion formulation. We analyze\nthose correlators using the rooted staggered chiral perturbation theory\n(rS$\\chi$PT), particular attention is paid to the bubble contribution. After\nchiral extrapolation, we obtain the physical $\\kappa$ mass with $828\\pm97$ MeV,\nwhich is within the recent experimental value $800\\sim900$MeV. These numerical\nsimulations are carried out with MILC 2+1 flavor gauge configurations at\nlattice spacing $a \\approx 0.12$ fm."
    },
    {
        "anchor": "Progress on Complex Langevin simulations of a finite density matrix\n  model for QCD: We study the Stephanov model, which is an RMT model for QCD at finite\ndensity, using the Complex Langevin algorithm. Naive implementation of the\nalgorithm shows convergence towards the phase quenched or quenched theory\nrather than to intended theory with dynamical quarks. A detailed analysis of\nthis issue and a potential resolution of the failure of this algorithm are\ndiscussed. We study the effect of gauge cooling on the Dirac eigenvalue\ndistribution and time evolution of the norm for various cooling norms, which\nwere specifically designed to remove the pathologies of the complex Langevin\nevolution. The cooling is further supplemented with a shifted representation\nfor the random matrices. Unfortunately, none of these modifications generate a\nsubstantial improvement on the complex Langevin evolution and the final results\nstill do not agree with the analytical predictions.",
        "positive": "Lattice QCD and Three-particle Decays of Resonances: Most strong-interaction resonances have decay channels involving three or\nmore particles, including many of the recently discovered $X$, $Y$ and $Z$\nresonances. In order to study such resonances from first principles using\nlattice QCD, one must understand finite-volume effects for three particles in\nthe cubic box used in calculations. Here we review efforts to develop a\nthree-particle quantization condition that relates finite-volume energies to\ninfinite-volume scattering amplitudes. We describe in detail the three\napproaches that have been followed, and present new results on the relationship\nbetween the corresponding results. We show examples of the numerical\nimplementation of all three approaches and point out the important issues that\nremain to be resolved."
    },
    {
        "anchor": "Lattice $B \\to D^{(*)}$ form factors, $R(D^{(*)})$, and $|V_{cb}|$: I discuss recent progress in lattice calculations of $B \\to D^{(*)} \\ell \\nu$\nform factors, important for the precision determination of $|V_{cb}|$ in the\nStandard Model (SM), and for testing SM expectations of lepton flavor\nuniversality in observables $R(D^{(*)})$. I also discuss progress in\ncalculations of the related $b \\to c$ semileptonic decays $B_s \\to D_s^{(*)}\n\\ell \\nu$ and $B_c \\to J/\\psi \\, \\ell \\nu$ now experimentally accessible at the\nLHC.",
        "positive": "Nucleon Gluon Distribution Function from 2+1+1-Flavor Lattice QCD: The parton distribution functions (PDFs) provide process-independent\ninformation about the quarks and gluons inside hadrons. Although the gluon PDF\ncan be obtained from a global fit to experimental data, it is not constrained\nwell in the large-$x$ region. Theoretical gluon-PDF studies are much fewer than\nthose of the quark PDFs. In this work, we present the first lattice-QCD results\nthat access the $x$-dependence of the gluon unpolarized PDF of the nucleon. The\nlattice calculation is carried out with nucleon momenta up to 2.16 GeV, lattice\nspacing $a\\approx0.12$ fm, with valence pion masses of 310 and 690 MeV. We use\nreduced Ioffe-time distributions to cancel the renormalization and implement a\none-loop perturbative pseudo-PDF matching to the lightcone distribution. Our\nmatrix element results in coordinate space are consistent with those obtained\nfrom the global PDF fits of CT18 NNLO and NNPDF3.1 NNLO. Our fitted gluon PDF\nextrapolated to the physical pion mass gives consistent results in the $x >\n0.3$ region."
    },
    {
        "anchor": "Pion-pion interaction in the I=1 channel: We present preliminary results of a new approach to the study of the\npion-pion system in the I=1 channel. The Bethe-Salpeter wave function of the\ntwo-pion system is computed on the ground state and the first excited state.\nFrom these, we attempt to extract an interaction kernel (potential) which can\nthen be used to extract observables such as the phase shifts. In a first trial,\nwe use rather large pion masses $m_\\pi \\sim 1.05$ GeV and $m_\\pi \\sim 0.68$ GeV\nwhich do not allow rho decay.",
        "positive": "A different kind of string: In U(1) lattice gauge theory in three spacetime dimensions, the problem of\nconfinement can be studied analytically in a semi-classical approach, in terms\nof a gas of monopoles with Coulomb-like interactions. In addition, this theory\ncan be mapped to a spin model via an exact duality transformation, which allows\none to perform high-precision numerical studies of the confining potential.\nTaking advantage of these properties, we carried out an accurate investigation\nof the effective string describing the low-energy properties of flux tubes in\nthis confining gauge theory. We found striking deviations from the expected\nNambu-Goto-like behavior, and, for the first time, evidence for contributions\nthat can be described by a term proportional to the extrinsic curvature of the\neffective string worldsheet. Such term is allowed by Lorentz invariance, and\nits presence in the infrared regime of the U(1) model was indeed predicted by\nPolyakov several years ago. Our results show that this term scales as expected\naccording to Polyakov's solution, and becomes the dominant contribution to the\neffective string action in the continuum limit. We also demonstrate\nanalytically that the corrections to the confining potential induced by the\nextrinsic curvature term can be related to the partition function of the\nmassive perturbation of a c=1 bosonic conformal field theory. The implications\nof our results for SU(N) Yang-Mills theories in three and in four spacetime\ndimensions are discussed."
    },
    {
        "anchor": "Lattice study on a tetra-quark state $T_{bb}$ in the HAL QCD method: We study a doubly-bottomed tetra-quark state $(bb\\bar{u}\\bar{d})$ with\nquantum number $I(J^P)=0(1^+)$, denoted by $T_{bb}$, in lattice QCD with the\nNon-Relativistic QCD (NRQCD) quark action for $b$ quarks. Employing\n$(2+1)$-flavor gauge configurations at $a \\approx 0.09$ {fm} on $32^3\\times 64$\nlattices, we have extracted the coupled channel potential between\n$\\bar{B}\\bar{B}^*$ and $\\bar{B}^* \\bar{B}^*$ in the HAL QCD method, which\npredicts an existence of a bound $T_{bb}$ below the $\\bar{B}\\bar{B}^*$\nthreshold. By extrapolating results at $m_\\pi\\approx 410,\\, 570,\\, 700$ {MeV}\nto the physical pion mass $m_\\pi\\approx140$ {MeV}, we obtain a biding energy\nwith its statistical error as $E_{\\rm binding}^{\\rm (single)} = 155(17)$ MeV\nand $E_{\\rm binding}^{\\rm (coupled)} = 83(10)$ MeV, where ``coupled\" means that\neffects due to virtual $\\bar{B}^* \\bar{B}^*$ states are included through the\ncoupled channel potential, while only a potential for a single\n$\\bar{B}\\bar{B}^*$ channel is used in the analysis for ``single\". A comparison\nshows that the effect from virtual $\\bar{B}^* \\bar{B}^*$ states is quite\nsizable to the binding energy of $T_{bb}$. We estimate systematic errors to be\n$\\pm 20$ MeV at most, which are mainly caused by the NRQCD approximation for\n$b$ quarks.",
        "positive": "A Few Points on Point-to-Point Correlation Functions: The short-time regime of QCD two-point correlation functions is examined\nthrough a QCD-Sum-Rule-inspired continuum model. QCD Sum Rule techniques are\ntested and alternate nucleon interpolating fields are discussed. The techniques\npresented here may be of practical use in determining heavy-light meson decay\nconstants."
    },
    {
        "anchor": "Precision Lattice Calculation of SU(2) 't Hooft loops: The [dual] string tension of a spatial 't Hooft loop in the deconfined phase\nof Yang-Mills theory can be formulated as the tension of an interface\nseparating different Z_N deconfined vacua. We review the 1-loop perturbative\ncalculation of this interface tension in the continuum and extend it to the\nlattice. The lattice corrections are large. Taking these corrections into\naccount, we compare Monte Carlo measurements of the dual string tension with\nperturbation theory, for SU(2). Agreement is observed at the 2% level, down to\ntemperatures O(10) T_c.",
        "positive": "Novel phases in strongly coupled four-fermion theories: We study a lattice model comprising four massless reduced staggered fermions\nin four dimensions coupled through an $SU(4)$-invariant four-fermion\ninteraction. We present both theoretical arguments and numerical evidence that\nno bilinear fermion condensates are present for any value of the four-fermi\ncoupling, in contrast to earlier studies of Higgs--Yukawa models with different\nexact lattice symmetries. At strong coupling we observe the formation of a\nfour-fermion condensate and a mass gap in spite of the absence of bilinear\ncondensates. Unlike those previously studied systems we do not find a\nferromagnetic phase separating this strong-coupling phase from the massless\nweak-coupling phase. Instead we observe long-range correlations in a narrow\nregion of the coupling, still with vanishing bilinear condensates. While our\nnumerical results come from relatively small lattice volumes that call for\ncaution in drawing conclusions, if this novel phase structure is verified by\nfuture investigations employing larger volumes it may offer the possibility for\nnew continuum limits for strongly interacting fermions in four dimensions."
    },
    {
        "anchor": "|V_cd| from D Meson Leptonic Decays: We present an update of the D meson decay constant f_D using the Highly\nImproved Staggered Quark (HISQ) action for valence charm and light quarks on\nMILC N_f = 2+1 lattices. The new determination incorporates HPQCD's improved\nscale r_1^{N_f = 2+1} = 0.3133(23) fm, accurately retuned bare charm quark\nmasses and data from an ensemble that is more chiral than in our previous\ncalculations. We find f_D = 208.3(3.4) MeV. Combining the new f_D with D -> \\mu\n\\nu\\ branching fraction data from CLEO-c, we extract the CKM matrix element\n|V_cd| = 0.223(10)_{exp.}(4)_{lat.}. This value is in excellent agreement with\n|V_cd| from D semileptonic decays and from neutrino scattering experiments and\nhas comparable total errors. We determine the ratio between semileptonic form\nfactor and decay constant and find [f^{D -> \\pi}_+(0) / f_D ]_{lat.} = 3.20(15)\nGeV^{-1} to be compared with the experimental value of [f^{D -> \\pi}_+(0) / f_D\n]_{exp.} = 3.19(18) GeV^{-1}. Finally, we mention recent preliminary but\nalready more accurate D -> \\mu \\nu\\ branching fraction measurements from BES\nIII and discuss their impact on precision |V_cd| determinations in the future.",
        "positive": "Generalized Potts-Models and their Relevance for Gauge Theories: We study the Polyakov loop dynamics originating from finite-temperature\nYang-Mills theory. The effective actions contain center-symmetric terms\ninvolving powers of the Polyakov loop, each with its own coupling. For a\nsubclass with two couplings we perform a detailed analysis of the statistical\nmechanics involved. To this end we employ a modified mean field approximation\nand Monte Carlo simulations based on a novel cluster algorithm. We find\nexcellent agreement of both approaches. The phase diagram exhibits both first\nand second order transitions between symmetric, ferromagnetic and\nantiferromagnetic phases with phase boundaries merging at three tricritical\npoints. The critical exponents $\\nu$ and $\\gamma$ at the continuous transition\nbetween symmetric and antiferromagnetic phases are the same as for the 3-state\nspin Potts model."
    },
    {
        "anchor": "Ising model as a $U(1)$ Lattice Gauge Theory with a $\u03b8$-term: We discuss a gauged XY model a $\\theta$-term on an arbitrary lattice in 1+1\ndimensions, and show that the theory reduces exactly to the 2d Ising model on\nthe dual lattice in the limit of the strong gauge coupling, provided that the\ntopological term is defined via the Villain action. We discuss the phase\ndiagram by comparing the strong and weak gauge coupling limits, and perform\nMonte Carlo simulations at intermediate couplings. We generalize the duality to\nhigher-dimensional Ising models using higher-form U(1) gauge field analogues.",
        "positive": "Determination of LambdaMS from the gluon and ghost propagators in Landau\n  gauge: We give an update on our lattice determination of r_0 LambdaMS for different\nNf. Our calculations employ the strong coupling constant in the minimal MOM\nscheme for QCD in Landau gauge, and we report here on our progress towards a\nquantitative understanding of the intrinsic lattice discretization artifacts at\nlarge momenta. This is important for a high-precision analysis, in particular\nfor the unquenched calculations for which the access to small lattice spacings\nis restricted by the available gauge configurations."
    },
    {
        "anchor": "Nicolai mapping vs. exact chiral symmetry on the lattice: Two-dimensional N=2 Wess-Zumino model is constructed on the lattice through\nNicolai mapping with Ginsparg-Wilson fermion. The Nicolai mapping requires a\ncertain would-be surface term in the bosonic action which ensures the vacuum\nenergy cancellation even on the lattice, but inevitably breaks chiral symmetry.\nWith the Ginsparg-Wilson fermion, the holomorphic structure of the would-be\nsurface term is maintained, leaving a discrete subgroup of the exact chiral\nsymmetry intact for a monomial scalar potential. By this feature both boson and\nfermion can be kept massless on the lattice without any fine-tuning.",
        "positive": "On the Interaction in Lattice Gauge Theory: Haag's theorem states that if a quantum field theory is Lorentz invariant and\nirreducible, there is no interaction picture. But if we construct quantum field\ntheory on a discrete lattice spacetime, its representation will be reducible\nand the interaction picture will be restored again."
    },
    {
        "anchor": "Tensor representations of lattice vertices from hypercubic symmetry: We present a symmetry-based method for obtaining suitable tensor descriptions\nof lattice vertex functions without spinor components. The approach is based on\nfinding the polynomial functions of vertex momenta, which satisfy the\nappropriate tensor transformation laws under hypercubic symmetry\ntransformations. We use the method to find the most general possible (up to\nfinite volume effects) basis decompositions for lattice vectors and second-rank\ntensors. The leading-order non-continuum versions of these representations are\nthen applied to the Landau gauge gluon propagator and ghost-gluon vertex of\nMonte Carlo simulations, to reveal two interesting insights. First, it is\ndemonstrated numerically and analytically that there exist special kinematic\nconfigurations where the basis descriptions of both functions reduce to their\ncontinuum analogues. Second, for the gluon two-point correlator it is shown\nthat the rate at which the function approaches its continuum form in the\ninfrared is independent of the lattice gauge coupling $\\beta$ (when working in\nlattice units): the said rate depends on kinematics alone and is ultimately\ndictated by the numerical gauge-fixing procedure. We also comment on how this\nreflects on the lattice investigations of the anomalous magnetic moment of the\nmuon. Finally, we argue how our findings can be used to directly test some of\nthe continuum extrapolation methods.",
        "positive": "Threshold expansion of the three-particle quantization condition: We recently derived a quantization condition for the energy of three\nrelativistic particles in a cubic box. Here we use this condition to study the\nenergy level closest to the three-particle threshold when the total\nthree-momentum vanishes. We expand this energy in powers of $1/L$, where $L$ is\nthe linear extent of the finite volume. The expansion begins at ${\\cal\nO}(1/L^3)$, and we determine the coefficients of the terms through ${\\cal\nO}(1/L^6)$. As is also the case for the two-particle threshold energy, the\n$1/L^3$, $1/L^4$ and $1/L^5$ coefficients depend only on the two-particle\nscattering length $a$. These can be compared to previous results obtained using\nnonrelativistic quantum mechanics and we find complete agreement. The $1/L^6$\ncoefficients depend additionally on the two-particle effective range $r$ (just\nas in the two-particle case) and on a suitably defined threshold three-particle\nscattering amplitude (a new feature for three particles). A second new feature\nin the three-particle case is that logarithmic dependence on $L$ appears at\n$\\mathcal O(1/L^6)$. Relativistic effects enter at this order, and the only\ncomparison possible with the nonrelativistic result is for the coefficient of\nthe logarithm, where we again find agreement. For a more thorough check of the\n$1/L^6$ result, and thus of the quantization condition, we also compare to a\nperturbative calculation of the threshold energy in relativistic $\\lambda\n\\phi^4$ theory, which we have recently presented. Here all terms can be\ncompared and we find full agreement."
    },
    {
        "anchor": "Large-N mesons: We present an update of our project of computing the meson spectrum and decay\nconstants in large-N QCD. The results are obtained in the quenched\napproximation with the Wilson fermion action for N = 2, 3, 4, 5, 6, 7 and 17\nand extrapolated to infinite N. We non-perturbatively determine the\nrenormalization factors for local quark bilinears that are needed to compute\nthe decay constants. We extrapolate our SU(7) results to the continuum limit,\nemploying four different lattice spacings.",
        "positive": "Extracting $F_\u03c0$ from small lattices: unquenched results: We calculate the response of the microscopic Dirac spectrum to an imaginary\nisospin chemical potential for QCD with two dynamical flavors in the chiral\nlimit. This extends our previous calculation from the quenched to the\nunquenched theory. The resulting spectral correlation function in the\n$\\epsilon$-regime provides here, too, a new and efficient way to measure\n$F_\\pi$ on the lattice. We test the method in a hybrid Monte Carlo simulation\nof the theory with two staggered quarks."
    },
    {
        "anchor": "Gliding down the QCD transition line, from $N_f=2$ till the onset of\n  conformality: We review the hot QCD transition with varying number of flavors, from two\ntill the onset of the conformal window. We discuss the universality class for\n$N_f=2$, along the critical line for two massless light flavors, and a third\nflavor whose mass serves as an interpolator between $N_f = 2$ and $N_f=3$. We\nidentify a possible scaling window for the 3D $O(4)$ universality class\ntransition, and its crossover to a mean field behaviour. We follow the\ntransition from $N_f=3$ to larger $N_f$, when it remains of first order, with\nan increasing coupling strength; we summarize its known properties, including\npossible cosmological applications as a model for a strong electroweak\ntransition. The first order transition, and its accompanying second order\nendpoint, finally morphs into the essential singularity at the onset of the\nconformal window, following the singular behaviour predicted by the Functional\nRenormalization Group.",
        "positive": "Hadronic decay of a scalar B meson from the lattice: We explore the transitions B$(0^+)$ to B $\\pi$ and B$_s(0^+)$ to B K from\nlattice QCD with $N_f=2$ flavours of sea quark, using the static approximation\nfor the heavy quark. We evaluate the effective coupling constants, predicting a\nB$(0^+)$ to B $\\pi$ width of around 160 MeV. Our result for the coupling\nstrength adds to the evidence that the B$_s(0^+)$ meson is not predominantly a\nmolecular state (BK)."
    },
    {
        "anchor": "The Spectral Structure of Correlator Matrices: In lattice QCD spectrum calculations, it is desirable to obtain multiple\nexcited state energies in each symmetry channel. Typically, one constructs\nseveral interpolating operators for the symmetry channel of interest, forms the\n`correlator matrix' of all possible two-point functions, and uses the\nvariational method to obtain as many energy levels as possible. We present a\ndetailed look at this last step, starting from a discussion of the symmetry\nproperties and spectral structure of the correlator matrix. We continue by\nmotivating and describing the variational method, before discussing some\nconceptual and practical challenges concerning the light baryon sector. We\nconclude by mentioning some alternate spectrum extraction methods currently\nunder study. Throughout, we attempt to quantify all approximations and\nassumptions, and we illustrate our points using a nucleon correlator matrix\nestimated on dynamical two-flavor lattice data.",
        "positive": "Cluster-Algorithm-Amenable Models of Gauge Fields and Matter: Typical fermion algorithms require the computation (or sampling) of the\nfermion determinant. We focus instead on cluster algorithms which do not\ninvolve the determinant and involve a more physically relevant sampling of the\nconfiguration space. We develop new cluster algorithms and design classes of\nmodels for fermions coupled to $\\mathbb{Z}_2$ and $U(1)$ gauge fields that are\namenable to being simulated by these cluster algorithms in a sign-problem free\nway. Such simulations should contain rich phase diagrams and are particularly\nrelevant for quantum simulator experiments."
    },
    {
        "anchor": "Finite-Size Scaling on the Ising Coexistence Line: We study the finite-size scaling of moments of the magnetization in the\nlow-temperature phase of the two-dimensional Ising model.",
        "positive": "L\u00fcscher's finite size method with twisted boundary conditions: an\n  application to $J/\u03c8$-$\u03c6$ system to search for narrow resonance: We investigate an application of twisted boundary conditions for study of\nlow-energy hadron-hadron interactions with L\\\"ushcer's finite size method. It\nallows us to calculate the phase shifts for elastic scattering of two hadrons\nat any small value of the scattering momentum even in a finite volume. We then\ncan extract model independent information of low-energy scattering parameters\nsuch as the scattering length, the effective range and the effective volume\nfrom the $S$-wave and $P$-wave scattering phase shifts through the effective\nrange expansion. This approach also enables us to examine the existence of\nnear-threshold and narrow resonance states, of which characteristic is observed\nin many of newly discovered charmonium-like $XYZ$ mesons. As a simple example,\nwe demonstrate our method for low-energy $J/\\psi$-$\\phi$ scatterings to search\nfor Y(4140) resonance using 2+1 flavor PACS-CS gauge configurations at the\nlightest pion mass, $m_{\\pi}=156$ MeV."
    },
    {
        "anchor": "Monte Carlo Simulations with Complex-Valued Measure: A simulation method based on the RG blocking is shown to yield statistical\nerrors smaller than that of the crude MC using absolute values of the original\nmeasures. The new method is particularly suitable to apply to the sign problem\nof indefinite or complex-valued measures. We demonstrate the many advantages of\nthis method in the simulation of 2D Ising model with complex-valued\ntemperature.",
        "positive": "Restoring rotational invariance for lattice QCD propagators: This note presents a method to reduce the discretization errors appearing\nwhen solving a Quantum Field Theory in a hypercubic lattice in both position\nand momentum-space. The method exploits the artifacts that break rotational\nsymmetry to recover rotationally invariant results for two-point Green\nfunctions. We show that a combination of the results obtained in position and\nmomentum space can be useful to signal the presence of rotationally invariant\nartifacts making use of their approximate Fourier transforms in the continuum.\nThe method will be introduced using a Klein-Gordon propagator, and a direct\napplication to gluon propagator in quenched lattice QCD will be given."
    },
    {
        "anchor": "Polynomial Subtraction Method for Disconnected Quark Loops: The polynomial subtraction method, a new numerical approach for reducing the\nnoise variance of Lattice QCD disconnected matrix elements calculation, is\nintroduced in this paper. We use the MinRes polynomial expansion of the QCD\nmatrix as the approximation to the matrix inverse and get a significant\nreduction in the variance calculation. We compare our results with that of the\nperturbative subtraction and find that the new strategy yields a faster\ndecrease in variance which increases with quark mass.",
        "positive": "Universality of the Axial Anomaly in Lattice QCD: We prove that lattice QCD generates the axial anomaly in the continuum limit\nunder very general conditions on the lattice action, which includes the case of\nGinsparg-Wilson fermions. The ingredients going into the proof are gauge\ninvariance, locality of the Dirac operator, absence of fermion doubling, the\ngeneral form of the lattice Ward identity, and the power counting theorem of\nReisz. The results generalize in an obvious way to SU(N) lattice gauge\ntheories."
    },
    {
        "anchor": "Transverse momentum distributions of quarks in the nucleon from Lattice\n  QCD: Transverse momentum dependent parton distribution functions (TMDPDFs) encode\ninformation about the intrinsic motion of quarks inside the nucleon. They are\nimportant non-perturbative ingredients in our understanding of, e.g., azimuthal\nasymmetries and other qualitative features in semi-inclusive deep inelastic\nscattering experiments. We present first calculations on the lattice, based on\nMILC gauge configurations and propagators from LHPC. They yield polarized and\nunpolarized transverse momentum dependent quark densities and enable us to test\nthe assumption of factorization in x and transverse momentum. The operators we\nemploy are non-local and contain a Wilson line, whose renormalization requires\nthe removal of a divergence linear in the cutoff 1/a.",
        "positive": "Improved method for calculating nucleon strangeness: The strange quark content of the nucleon, as well as other matrix elements,\ncan be calculated on the lattice by examining correlations between the nucleon\npropagator and the quark condensate. The largest contribution to statistical\nerror comes from fluctuations in the condensate far from the propagation region\nthat contribute only noise. We will report on a technique for considering only\nthe condensate near the propagation region, significantly reducing the\nstatistical error."
    },
    {
        "anchor": "Progress on a canonical finite density algorithm: We test the finite density algorithm in the canonical ensemble which combines\nthe HMC update with the accept/reject step according to the ratio of the\nfermion number projected determinant to the unprojected one as a way of\navoiding the determinant fluctuation problem. We report our preliminary results\non the Polyakov loop in different baryon number sectors which exhibit\ndeconfinement transitions on small lattices. The largest density we obtain\naround $T_c$ is an order of magnitude larger than that of nuclear matter. From\nthe conserved vector current, we calculate the quark number and verify that the\nmixing of different baryon sectors is small.",
        "positive": "On the Deconfinement Phase Transition in Hot Gauge Theories with\n  Dynamical Matter Fields: The phase structure of hot gauge theories with dynamical matter fields is\nreexamined in the canonical ensemble with respect to triality. Since this\nensemble implies a projection to the zero triality sector of the theory we\nintroduce a proper quantity which is able to reveal a critical behaviour of the\ntheory with fundamental quarks. We discuss the properties of both the\nchromoelectric and chromomagnetic sectors of the theory and show while electric\ncharges carrying a unit of Z(N) charge are screened at high temperatures by\ndynamical matter loops, this is not the case for the Z(N) magnetic flux. An\norder parameter is constructed to probe the realization of local discrete Z(N)\nsymmetry in the magnetic sector. We argue it can be used to detect a\ndeconfinement phase being defined in terms of the screening mechanism as a\nphase of unscreened Z(N) flux. It may be detectable at long range via the\nAharonov-Bohm effect. We discuss the possible phase structure of QCD in this\napproach."
    },
    {
        "anchor": "Physics at Tevatron Run II: We present recent physics results from the Tevatron Collider experiments CDF\nand D0. (contribution to Lattice 2004)",
        "positive": "Testing importance sampling on a quantum annealer for strong coupling\n  SU(3) gauge theory: $SU(N_c)$ gauge theories in the strong coupling limit can be described by\ninteger variables representing monomers, dimers and baryon loops. We\ndemonstrate how the D-wave quantum annealer can perform importance sampling on\n$U(N_c)$ gauge theory in the strong coupling formulation of this theory. In\naddition to causing a sign problem in importance sampling, baryon loops induce\na complex QUBO matrix which cannot be optimized by the D-Wave annealer. Instead\nwe show that simulating the sign-problem free quenched action on the D-Wave is\nsufficient when combined with a sign reweighting method. As the first test on\n$SU(3)$ gauge theory, we simulate on $2 \\times 2$ lattice and compare the\nresults with its analytic solutions."
    },
    {
        "anchor": "Vector meson at non-zero baryon density and zero sound: We present simulation results of the (2+1)d four-fermion model with a baryon\nchemical potential. We examine temporal correlation functions of the vector\nmeson, and find evidence of phonon-like behavior characterised by a linear\ndispersion relation in the long wavelength limit. We also discuss the\nconsistency of our numerical results with analytical solutions to the Boltzmann\nequation corresponding to zero sound. We argue that our results provide the\nfirst evidence for a collective excitation in a lattice simulation.",
        "positive": "Partially quenched QCD with a chemical potential: Using a chiral random matrix theory we can now derive the low energy\npartition functions and Dirac eigenvalue correlations of QCD with different\nchemical potentials for the dynamical and valence quarks. The results can also\nbe extended to complex (and purely imaginary) chemical potential. We also\ndiscuss possible applications such as fitting to low energy constants and\nunderstanding the phase diagrams of the full and partially quenched theories."
    },
    {
        "anchor": "Four Fermion Models at Non-Zero Density: I review the properties of the three-dimensional Gross-Neveu model formulated\nwith non-zero chemical potential and temperature, focussing on results obtained\nby lattice Monte Carlo simulation.",
        "positive": "The pion-pion Interaction in the rho Channel in Finite Volume: The aim of this paper is to investigate an efficient strategy that allows to\nobtain pi-pi phase shifts and rho meson properties from QCD lattice data with\nhigh precision. For this purpose we evaluate the levels of the pi-pi system in\nthe rho channel in finite volume using chiral unitary theory. We investigate\nthe dependence on the pi mass and compare with other approaches which use QCD\nlattice calculations and effective theories. We also illustrate the errors\ninduced by using the conventional Luscher approach instead of a more accurate\none recently developed that takes into account exactly the relativistic two\nmeson propagators. Finally we make use of this latter approach to solve the\ninverse problem, getting pi-pi phase shifts from \"synthetic\" lattice data,\nproviding an optimal strategy and showing which accuracy is needed in these\ndata to obtain the $\\rho$ properties with a desired accuracy."
    },
    {
        "anchor": "mu-Squared Dependent Deviation of the Non Perturbative ZA,MOM from the\n  True Axial Renormalisation Constant, Implied by Ward Identity: It is recalled why, as already stated in a previous paper, there seems to be\nan inconsistency in identifying the non perturbative ZA,MOM as the\nrenormalisation of the axial current, or equivalently, in setting as\nnormalisation condition that the renormalised vertex=1 at p^2 = mu^2 at some\nrenormalisation scale mu, where p is the momentum in the legs. Indeed, unlike\nthe vector case, the Ward-Takahashi (WT) identity for the axial current is\nshown to imply both the renormalisation scale independence of ZA and a mu2\ndependence of ZA,MOM. This mu^2 dependence is simply related to certain\ninvariants in the pseudoscalar vertex and can persist in the chiral limit due\nto the spontaneous breaking of chiral symmetry (pion pole). It is seen clearly\nin the mu^2 dependence of some lattice calculations of ZA,MOM/ZV,MOM near the\nchiral limit.",
        "positive": "Simulating QCD at finite density with static quarks: We study lattice QCD in the limit that the quark mass and chemical potential\nare simultaneously made large, resulting in a controllable density of quarks\nwhich do not move; this is similar in spirit to the quenched approximation for\nzero density QCD. In this approximation we find that the deconfinement\ntransition seen at zero density becomes a smooth crossover for any nonzero\ndensity at which we simulated, and that at low enough temperature chiral\nsymmetry remains broken at all densities."
    },
    {
        "anchor": "Architectural choices for the Columbia 0.8 Teraflops machine: We discuss the hardware design choices made in our 16K-node 0.8 Teraflops\nsupercomputer project, a machine architecture optimized for full QCD\ncalculations. The efficiency of the conjugate gradient algorithm in terms of\nbalance of floating-point operations, memory handling and utilization, and\ncommunication overhead is addressed. We also discuss the technological\ninnovations and software tools that facilitate hardware design and what\nopportunities these give to the academic community.",
        "positive": "An alternate smearing method for Wilson loops in lattice QCD: A gauge field link smearing method developed for calculations with staggered\nfermions, namely the use of unitarized fat7 links, is applied to mesonic and\nbaryonic Wilson loop calculations. This method is found to be very effective\nfor reducing statistical fluctuations for large Wilson loops. Examination of\nchromo-electric field distributions shows that self-interactions of the static\nsources are reduced when unitarized fat7 smearing is used but long-distance\ninter-quark effects are unchanged."
    },
    {
        "anchor": "The canonical approach to Finite Density QCD: We present a canonical approach to study properties of QCD at finite baryon\ndensity rho, and apply it to the determination of the phase diagram of\nfour-flavour QCD. For a pion mass of about 350 MeV, the first-order transition\nbetween the hadronic and the plasma phase gives rise to a co-existence region\nin the T-rho plane, which we study in detail. We obtain accurate results for\nsystems containing up to 30 baryons and quark chemical potentials mu up to 2T.\nOur T-mu phase diagram agrees with the literature when mu/T < 1. At larger\nchemical potential, we observe a ``bending down'' of the phase boundary. We\ncharacterise the two phases with simple models: the hadron resonance gas in the\nhadronic phase, the free massless quark gas in the plasma phase.",
        "positive": "$D_s$ physics from fine lattices: We present a preliminary analysis of the charm quark mass and the mass and\ndecay constant $f_{D_s}$ of the $D_s$ meson obtained from dynamical simulations\nof $N_f = 2$ Wilson QCD on the large and fine lattices simulated by the CLS\neffort."
    },
    {
        "anchor": "Lattice Quantum Gravity: EDT and CDT: This article is an overview of the use of so-called Euclidean Dynamical\nTriangulations (EDT) and Causal Dynamical Triangulations (CDT) as lattice\nregularizations of quantum gravity. The lattice regularizations have been very\nsuccessful in the case of two-dimensional quantum gravity, where the lattice\ntheories indeed provide regularizations of continuum well defined quantum\ngravity theories. In four-dimensional spacetime the Einstein-Hilbert action\nleads to a theory of gravity which is not renormalizable as a perturbative\nquantum theory around flat spacetime. It is discussed how lattice gravity in\nthe form of EDT or CDT can be used to search for a non-perturbative UV fixed\npoint of the lattice renormalization group in the spirit of asymptotic safety.\nIn this way it might be possible to define a quantum theory of gravity also at\nlengthscales smaller than the Planck length.",
        "positive": "Dynamical QCD simulations on anisotropic lattices: The simulation of QCD on dynamical (Nf=2) anisotropic lattices is described.\nA method for nonperturbative renormalisation of the parameters in the\nanisotropic gauge and quark actions is presented. The precision with which this\ntuning can be carried out is determined in dynamical simulations on 8^3x48 and\n8^3x80 lattices."
    },
    {
        "anchor": "QCD thermodynamics with continuum extrapolated dynamical overlap\n  fermions: We study the finite temperature transition in QCD with two flavors of\ndynamical fermions at a pseudoscalar pion mass of about 350 MeV. We use\nlattices with temporal extent of $N_t$=8, 10 and 12. For the first time in the\nliterature a continuum limit is carried out for several observables with\ndynamical overlap fermions. These findings are compared with results obtained\nwithin the staggered fermion formalism at the same pion masses and extrapolated\nto the continuum limit. The presented results correspond to fixed topology and\nits effect is studied in the staggered case. Nice agreement is found between\nthe overlap and staggered results.",
        "positive": "Damaging 2D Quantum Gravity: We investigate numerically the behaviour of damage spreading in a Kauffman\ncellular automaton with quenched rules on a dynamical $\\phi^3$ graph, which is\nequivalent to coupling the model to discretized 2D gravity. The model is\ninteresting from the cellular automaton point of view as it lies midway between\na fully quenched automaton with fixed rules and fixed connectivity and a\n(soluble) fully annealed automaton with varying rules and varying connectivity.\nIn addition, we simulate the automaton on a fixed $\\phi^3$ graph coming from a\n2D gravity simulation as a means of exploring the graph geometry."
    },
    {
        "anchor": "$B - \\bar B$ Mixing in the HQET: We present a high statistics, quenched lattice calculation of the\nB-parameters $B_{B_d}$ and $B_{B_s}$, computed at lowest order in the HQET. The\nresults were obtained using a sample of 600 quenched gauge field\nconfigurations, generated by Monte Carlo simulation at $\\beta=6.0$ on a\n$24^{3}\\times 40$ lattice. For the light quarks the SW-Clover action was used;\nthe propagator of the lattice HQET was also tree-level improved. Our best\nestimate of the renormalization scale independent B-parameter is $\\hat{B}_{B_d}\n= 1.03 \\pm 0.06 \\pm 0.18$. $\\hat{B}_{B_d}$ has been obtained by using\n``boosted'' perturbation theory to calculate the renormalization constants\nwhich relate the matrix elements of the lattice operators to the corresponding\namplitudes in the continuum. Due to the large statistics, the errors in the\nextraction of the matrix elements of the relevant bare operators are rather\nsmall. The main systematic error, corresponding to $\\pm 0.18$ in the above\nresult, comes from the uncertainty in the evaluation of the renormalization\nconstants, for which the one-loop corrections are rather large. The\nnon-perturbative evaluation of these constants will help to reduce the final\nerror. We also obtain $\\hat{B}_{B_s}/\\hat{B}_{B_d} = 1.01 \\pm 0.01$ and\n$f^2_{B_s}\\hat{B}_{B_s}/f^2_{B_d}\\hat{B}_{B_d} = 1.38 \\pm 0.07$.",
        "positive": "Complex-Temperature Properties of the Ising Model on 2D Heteropolygonal\n  Lattices: Using exact results, we determine the complex-temperature phase diagrams of\nthe 2D Ising model on three regular heteropolygonal lattices, $(3 \\cdot 6 \\cdot\n3 \\cdot 6)$ (kagom\\'{e}), $(3 \\cdot 12^2)$, and $(4 \\cdot 8^2)$ (bathroom\ntile), where the notation denotes the regular $n$-sided polygons adjacent to\neach vertex. We also work out the exact complex-temperature singularities of\nthe spontaneous magnetisation. A comparison with the properties on the square,\ntriangular, and hexagonal lattices is given. In particular, we find the first\ncase where, even for isotropic spin-spin exchange couplings, the nontrivial\nnon-analyticities of the free energy of the Ising model lie in a\ntwo-dimensional, rather than one-dimensional, algebraic variety in the\n$z=e^{-2K}$ plane."
    },
    {
        "anchor": "Lattice simulations of $G_2$-QCD at finite density: $G_2$-QCD, in which the exceptional Lie group $G_2$ replaces the $SU(3)$\ngauge group of QCD, does not suffer from a fermion sign problem. It can\ntherefore be simulated also at comparatively low temperatures and high\ndensities on the lattice, which hence allows to map out the phase diagram of\nthis QCD-like theory. We briefly review some of our previous results from such\nfinite density simulations to then present further evidence for a first-order\ntransition to what might be called $G_2$-nuclear matter. In order to isolate\ndiquark condensation effects, we introduce simulations with Majorana fermions\nand diquark sources. This allows to disentangle states in the spectrum that are\nconnected by charge conjugation. We discuss chiral symmetry in the presence of\ndiquark sources and present first results from our ongoing large-scale\nsimulations.",
        "positive": "Progress towards a lattice determination of (moments of) nucleon\n  structure functions: Using unimproved and non-perturbatively O(a) improved Wilson fermions,\nresults are given for the three lowest moments of unpolarised nucleon structure\nfunctions. Renormalisation, chiral extrapolation and the continuum limit of the\nmatrix elements are briefly discussed. The simulations are performed for both\nquenched and two flavours of unquenched fermions. No obvious sign of deviation\nfrom linearity in the chiral extrapolations are found. (This is most clearly\nseen in our quenched unimproved data, which extends to lighter quark mass.)\nPossible quenching effects also seem to be small. The lowest moment thus\nremains too large, so it seems to be necessary to reach smaller quark masses in\nnumerical simulations."
    },
    {
        "anchor": "The colour adjoint static potential from Wilson loops with generator\n  insertions and its physical interpretation: We discuss the non-perturbative computation and interpretation of a colour\nadjoint static potential based on Wilson loops with generator insertions.\nNumerical lattice results for SU(2) gauge theory are presented and compared to\ncorresponding perturbative results.",
        "positive": "Light Quark Masses from Lattice QCD: We present estimates of the masses of light quarks using lattice data. Our\nmain results are based on a global analysis of all the published data for\nWilson, Sheikholeslami-Wohlert (clover), and staggered fermions, both in the\nquenched approximation and with $n_f=2$ dynamical flavors. We find that the\nvalues of masses with the various formulations agree after extrapolation to the\ncontinuum limit for the $n_f=0$ theory. Our best estimates, in the MSbar scheme\nat $\\mu=2 GeV$, are $\\mbar=3.4 +- 0.4 +- 0.3 MeV$ and $m_s = 100 +- 21 +- 10\nMeV$ in the quenched approximation. The $n_f=2$ results, $\\mbar = 2.7 +- 0.3 +-\n0.3 MeV$ and $m_s = 68 +- 12 +- 7 MeV$, are preliminary. (A linear\nextrapolation in $n_f$ would further reduce these estimates for the physical\ncase of three dynamical flavors.) These estimates are smaller than\nphenomenological estimates based on sum rules, but maintain the ratios\npredicted by chiral perturbation theory. The new results have a significant\nimpact on the extraction of $\\epsilon'/\\epsilon$ from the Standard Model. Using\nthe same lattice data we estimate the quark condensate using the\nGell-Mann-Oakes-Renner relation. Again the three formulations give consistent\nresults after extrapolation to $a=0$, and the value turns out to be\ncorrespondingly larger, roughly preserving $m_s \\vev{\\bar \\psi \\psi}$."
    },
    {
        "anchor": "Phase structure and confinement properties of noncompact gauge theories\n  II. Z(N) Wilson loop and effective noncompact model: An approach to studying lattice gauge models in the weak coupling region is\nproposed. Conceptually, it is based on the crucial role of the original Z(N)\nsymmetry and the invariant gauge group measure. As an example, we calculate an\neffective model from the compact Wilson formulation of the SU(2) gauge theory\nin $d=3D3$ dimensions at zero temperature. Confining properties and phase\nstructure of the effective model are studied in details.",
        "positive": "Disconnected Loops with Twisted Mass Lattice QCD: We give a general introduction and discussion of the issues involved in using\nthe twisted mass formulation of lattice fermions in the context of disconnected\nloop calculations, including a short orientation on the present experimental\nsituation for nucleon strange quark form factors. A prototype calculation of\nthe disconnected part of the nucleon scalar form factor is described."
    },
    {
        "anchor": "Isospin-$\\frac{1}{2}$ $D\u03c0$ scattering and the $D_0^*$ resonance: Preliminary lattice QCD results for $D\\pi$ scattering in isospin\n$I=\\frac{1}{2}$ channel are presented. Utilizing the $N_f=2+1$ Wilson-Clover\nconfiguration at two volumes ($L^3 \\times T=32^3 \\times 96$ and $48^3 \\times\n96$) with the same lattice spacing ($a=0.07746(18)$ fm) and pion mass ($m_\\pi\n\\approx 303$ MeV), various two-particle operators in both the COM and the\nmoving frames are constructed and the corresponding finite-volume spectra are\ndetermined from their correlation functions. The $S$ and $P$-wave scattering\nphase shifts are then extracted using the L\\\"uscher approach, assuming\nnegligible contributions from higher partial waves. A virtual state associated\nwith the $D_0^*$ is also identified.",
        "positive": "Precision charmonium and D physics from lattice QCD and determination of\n  the charm quark mass: I will describe recent results from the HPQCD collaboration using a new very\naccurate method for charm quarks in lattice QCD, that we have used in\ncalculations including the full effect of u, d and s sea quarks. Multiple\nvalues of the lattice spacing and of the u, d and s sea quark masses allow us\nto extrapolate reliably, with a full error budget, to the real world. This\nopens up the field of charm physics to precision lattice QCD tests. So far we\nhave calculated the D and D_s meson masses to 6 MeV, having fixed the charm\nquark mass from the eta_c meson. Our D and D_s decay constants (determined to\n2%) make an interesting comparison to CLEO-c results as we await improved\nexperimental errors. We are also able to determine the charm quark mass to an\naccuracy of 1% using charmonium correlators and high-order continuum QCD\nperturbation theory. Future calculations are briefly discussed."
    },
    {
        "anchor": "LatticeQCD using OpenCL: We report on our implementation of LatticeQCD applications using OpenCL. We\nfocus on the general concept and on distributing different parts on hybrid\nsystems, consisting of both CPUs (Central Processing Units) and GPUs (Graphic\nProcessing Units).",
        "positive": "m_b and f_Bs from a combination of HQET and QCD: We compute the mass of the b-quark and the B_s meson decay constant in\nquenched lattice QCD using a combination of HQET and the standard relativistic\nQCD Lagrangian. We start from a small volume, where one can directly deal with\nthe b-quark, and compute the evolution to a big volume, where the finite size\neffects are negligible through step scaling functions which give the change of\nthe observables when L is changed to 2L. In all steps we extrapolate to the\ncontinuum limit, separately in HQET and in QCD for masses below m_b. The point\nm_b is then reached by an interpolation of the continuum results. With r_0=0.5\nfm and the experimental B_s and K masses we find f_Bs=191(6) MeV and the\nrenormalization group invariant mass M_b=6.89(11) GeV, translating into\nm_b(m_b)=4.42(7) GeV in the MS-bar scheme."
    },
    {
        "anchor": "Approaching nuclear interactions with lattice QCD: Nuclei make up the majority of the visible matter in the Universe; obtaining\na first principles description of the nuclear properties and interactions\nbetween nuclei directly from the underlying theory of the strong interaction,\nQuantum Chromodynamics (QCD), is one of the main goals of the nuclear physics\ncommunity. Although the theory was established nearly fifty years ago, the\ncomplexities of QCD at low energies precludes analytical solutions of the\nsimplest hadronic systems, let alone the features of the nuclear forces. In\nthis thesis we follow the lattice QCD approach, according to which QCD is\nsolved non-perturbatively in a discretized space-time via large-scale numerical\ncalculations. Specifically, the interactions between two octet baryons, with\nstrangeness ranging from 0 to -4, are studied at low energies with\nlarger-than-physical quark masses, and the low-energy coefficients in pionless\neffective field thepry relevant for two-baryon interactions, including those\nresponsible for SU(3) flavor-symmetry breaking, are constrained.",
        "positive": "Center Vortices and the Gribov Horizon: We show how the infinite color-Coulomb energy of color-charged states is\nrelated to enhanced density of near-zero modes of the Faddeev-Popov operator,\nand calculate this density numerically for both pure Yang-Mills and gauge-Higgs\nsystems at zero temperature, and for pure gauge theory in the deconfined phase.\nWe find that the enhancement of the eigenvalue density is tied to the presence\nof percolating center vortex configurations, and that this property disappears\nwhen center vortices are either removed from the lattice configurations, or\ncease to percolate. We further demonstrate that thin center vortices have a\nspecial geometrical status in gauge-field configuration space: Thin vortices\nare located at conical or wedge singularities on the Gribov horizon. We show\nthat the Gribov region is itself a convex manifold in lattice configuration\nspace. The Coulomb gauge condition also has a special status; it is shown to be\nan attractive fixed point of a more general gauge condition, interpolating\nbetween the Coulomb and Landau gauges."
    },
    {
        "anchor": "Lattice QCD investigation of a doubly-bottom $\\bar{b} \\bar{b} u d$\n  tetraquark with quantum numbers $I(J^P) = 0(1^+)$: We use lattice QCD to investigate the spectrum of the $\\bar{b} \\bar{b} u d$\nfour-quark system with quantum numbers $I(J^P) = 0(1^+)$. We use five different\ngauge-link ensembles with $2+1$ flavors of domain-wall fermions, including one\nat the physical pion mass, and treat the heavy $\\bar{b}$ quark within the\nframework of lattice nonrelativistic QCD. Our work improves upon previous\nsimilar computations by considering in addition to local four-quark\ninterpolators also nonlocal two-meson interpolators and by performing a\nL\\\"uscher analysis to extrapolate our results to infinite volume. We obtain a\nbinding energy of $(-128 \\pm 24 \\pm 10) \\, \\textrm{MeV}$, corresponding to the\nmass $(10476 \\pm 24 \\pm 10) \\, \\textrm{MeV}$, which confirms the existence of a\n$\\bar{b} \\bar{b} u d$ tetraquark that is stable with respect to the strong and\nelectromagnetic interactions.",
        "positive": "Phase structure of lattice QCD at finite temperature for 2+1 flavors of\n  Kogut-Susskind quarks: We report on a study of the finite-temperature chiral transition on an\n$N_t=4$ lattice for 2+1 flavors of Kogut-Susskind quarks. We find the point of\nphysical quark masses to lie in the region of crossover, in agreement with\nresults of previous studies. Results of a detailed examination of the\n$m_{u,d}=m_s$ case indicate vanishing of the screening mass of $\\sigma$ meson\nat the end point of the first-order transition."
    },
    {
        "anchor": "The continuum limit in the quenched approximation: Previous work at $6/g^2=5.7$ with quenched staggered quarks is extended with\nnew calculations at 5.85 and 6.15 on lattices up to $32^3\\times 64$. These\ncalculations allow a more detailed study of extrapolation in quark mass, finite\nvolume and lattice spacing than has heretofore been possible. We discuss how\nclosely the quenched spectrum approaches that of the real world.",
        "positive": "Twisted mass QCD and lattice approaches to the $\u0394I = 1/2$ rule: Twisted mass lattice QCD (tmQCD), generalised to four Wilson quark flavours,\ncan be used for the computation of some weak matrix elements related to $\\Delta\nI=1/2$ transitions. Besides eliminating unphysical zero modes, tmQCD may\nalleviate long-standing renormalisation problems of the four-quark operators\nwhich contribute to CP-conserving $K\\to\\pi$ transitions. With an active charm\nquark, the renormalisation of the $K\\to\\pi$ matrix elements requires at most\nthe subtraction of a linearly divergent counterterm. Furthermore, in the\n(partially) quenched approximation the twist angles can be chosen so that only\na finite counterterm needs to be subtracted."
    },
    {
        "anchor": "Finding the effective Polyakov line action for SU(3) gauge theories at\n  finite chemical potential: Motivated by the sign problem, we calculate the effective Polyakov line\naction corresponding to certain SU(3) lattice gauge theories on a ${16^3 \\times\n6}$ lattice via the \"relative weights\" method introduced in our previous\narticles. The calculation is carried out at $\\beta=5.6,5.7$ for the pure gauge\ntheory, and at $\\beta=5.6$ for the gauge field coupled to a relatively light\nscalar particle. In the latter example we determine the effective theory also\nat finite chemical potential, and show how observables relevant to phase\nstructure can be computed in the effective theory via mean field methods. In\nall cases a comparison of Polyakov line correlators in the effective theory and\nthe underlying lattice gauge theory, computed numerically at zero chemical\npotential, shows accurate agreement down to correlator magnitudes of order\n$10^{-5}$. We also derive the effective Polyakov line action corresponding to a\ngauge theory with heavy quarks and large chemical potential, and apply mean\nfield methods to extract observables.",
        "positive": "SO(2N) and SU(N) gauge theories in 2+1 dimensions: We perform an exploratory investigation of how rapidly the physics of SO(2N)\ngauge theories approaches its N=oo limit. This question has recently become\ntopical because SO(2N) gauge theories are orbifold equivalent to SU(N) gauge\ntheories, but do not have a finite chemical potential sign problem. We consider\nonly the pure gauge theory and, because of the inconvenient location of the\nlattice strong-to-weak coupling 'bulk' transition in 3+1 dimensions, we largely\nconfine our numerical calculations to 2+1 dimensions. We discuss analytic\nexpectations in both D=2+1 and D=3+1, show that the SO(6) and SU(4) spectra do\nindeed appear to be the same, and show that a number of mass ratios do indeed\nappear to agree in the large-N limit. In particular SO(6) and SU(3) gauge\ntheories are quite similar except for the values of the string tension and\ncoupling, both of which differences can be readily understood."
    },
    {
        "anchor": "Dynamic Critical Behavior of Multi-Grid Monte Carlo for Two-Dimensional\n  Nonlinear $\u03c3$-Models: We introduce a new and very convenient approach to multi-grid Monte Carlo\n(MGMC) algorithms for general nonlinear $\\sigma$-models: it is based on\nembedding an $XY$ model into the given $\\sigma$-model, and then updating the\ninduced $XY$ model using a standard $XY$-model MGMC code. We study the dynamic\ncritical behavior of this algorithm for the two-dimensional $O(N)$\n$\\sigma$-models with $N = 3,4,8$ and for the $SU(3)$ principal chiral model. We\nfind that the dynamic critical exponent $z$ varies systematically between these\ndifferent asymptotically free models: it is approximately 0.70 for $O(3)$, 0.60\nfor $O(4)$, 0.50 for $O(8)$, and 0.45 for $SU(3)$. It goes without saying that\nwe have no theoretical explanation of this behavior.",
        "positive": "Comment on `Asymptotic Scaling in the Two-Dimensional O(3) sigma-Model\n  at Correlation Length 10^5' by S. Caracciolo et al: We explain why in our view an extrapolation from small lattices containing\nonly perturbative information cannot be sufficient to determine nonperturbative\nqunatities and therefore cannot lead to a trustworthy determination of the\ncorrelation length."
    },
    {
        "anchor": "The two-dimensional twisted reduced principal chiral model revisited: Motivated by our previous study of the Twisted Eguchi-Kawai model for non\nminimal twists, we re-examined the behaviour of the reduced version of the two\ndimensional principal chiral model. We show that this single matrix model\nreproduces the same features as the standard lattice model. In particular,\nscaling towards the continuum limit, the correct value of the internal energy,\nthe magnetic susceptibility and the mass gap. Given our capacity to reach\nlarger values of $N$, we use the reduced model to study the nature and\nproperties of its large $N$ phase transition existing at intermediate coupling.\nWe conclude that the transition is of first order",
        "positive": "Past, present, and future of precision determinations of the QCD\n  coupling from lattice QCD: Non-perturbative scale-dependent renormalization problems are ubiquitous in\nlattice QCD as they enter many relevant phenomenological applications. They\nrequire solving non-perturbatively the renormalization group equations for the\nQCD parameters and matrix elements of interest in order to relate their\nnon-perturbative determinations at low energy to their high-energy counterparts\nneeded for phenomenology. Bridging the large energy separation between the\nhadronic and perturbative regimes of QCD, however, is a notoriously difficult\ntask. In this contribution we focus on the case of the QCD coupling. We\ncritically address the common challenges that state-of-the-art lattice\ndeterminations have to face in order to be significantly improved. In addition,\nwe review a novel strategy that has been recently put forward in order to solve\nthis non-perturbative renormalization problem and discuss its implications for\nfuture precision determinations. The new ideas exploit the decoupling of heavy\nquarks to match $N_{\\rm f}$-flavor QCD and the pure Yang-Mills theory. Through\nthis matching the computation of the non-perturbative running of the coupling\nin QCD can be shifted to the computationally much easier to solve pure-gauge\ntheory. We shall present results for the determination of the\n$\\Lambda$-parameter of $N_{\\rm f}=3$-flavor QCD where this strategy has been\napplied and proven successful. The results demonstrate that these techniques\nhave the potential to unlock unprecedented precision determinations of the QCD\ncoupling from the lattice. The ideas are moreover quite general and can be\nconsidered to solve other non-perturbative renormalization problems."
    },
    {
        "anchor": "D-decays with unquenched Lattice QCD: We discuss the recent progress in computing the D-meson decay constant and\nD->pi l nu form factors from the lattice QCD simulations with Nf=2 dynamical\nusing Wilson quarks. We report fD=201(20)MeV and F+(1GeV^2)/fD=4.04(78)GeV^-1\nat a=0.08fm.",
        "positive": "Updating algorithms with multi-step stochastic correction: Nested multi-step stochastic correction offers a possibility to improve\nupdating algorithms for numerical simulations of lattice gauge theories with\nfermions. The corresponding generalisations of the two-step multi-boson (TSMB)\nalgorithm as well as some applications with hybrid Monte Carlo (HMC) algorithms\nare considered."
    },
    {
        "anchor": "Calculation of the renormalized charmed-quark mass in Lattice QCD: The correlator of heavy-quark currents is calculated in quenched Lattice QCD\non a $16^3 \\times 32$-lattice for $\\beta= { 6, 6.3 }$. The renormalized charmed\nquark mass is extracted from the short-distance part of that correlator:\n$m_c^{\\overline{MS}}(m_c) = 1.22(5) GeV$. We study the sensitivity of our data\nto the strong coupling constant.",
        "positive": "Finite size analysis of the 3D gonihedric Ising model with k=0: This paper has been withdrawn"
    },
    {
        "anchor": "The spectrum of the three-dimensional adjoint Higgs model and hot SU(2)\n  gauge theory: We compute the mass spectrum of the SU(2) adjoint Higgs model in 2+1\ndimensions at several points located in the (metastable) confinement region of\nits phase diagram. We find a dense spectrum consisting of an almost unaltered\nrepetition of the glueball spectrum of the pure gauge theory, and additional\nbound states of adjoint scalars. For the parameters chosen, the model\nrepresents the effective finite temperature theory for pure SU(2) gauge theory\nin four dimensions, obtained after perturbative dimensional reduction.\nComparing with the spectrum of screening masses obtained in recent simulations\nof four-dimensional pure gauge theory at finite temperature, for the low lying\nstates we find quantitative agreement between the full and the effective theory\nfor temperatures as low as T = 2 Tc. This establishes the model under study as\nthe correct effective theory, and dimensional reduction as a viable tool for\nthe description of thermodynamic properties. We furthermore compare the\nperturbative contribution O(g.T) with the non-perturbative contributions\nO(g^2.T) and O(g^3.T) to the Debye mass. The latter turns out to be dominated\nby the scale g^2.T, whereas higher order contributions are small corrections.",
        "positive": "Topologically invariant transformation for lattice fermions: A transformation is devised to convert any lattice Dirac fermion operator\ninto a Ginsparg-Wilson Dirac fermion operator. For the standard Wilson-Dirac\nlattice fermion operator, the transformed new operator is local, free of O(a)\nlattice artifacts, has correct axial anomaly in the trivial sector, and is not\nplagued by the notorious problems (e.g., additive mass renormalization) which\noccur to the standard Wilson-Dirac lattice fermion operator."
    },
    {
        "anchor": "Heavy-light baryonic mass splittings from the lattice: We present lattice estimates of the mass of the heavy-light baryons\n$\\Lambda_b$ and $\\Xi_b$ obtained using propagating heavy quarks. For\n$\\Lambda_b$ our result is $M_{\\Lambda_b}=5.728 \\pm 0.144 \\pm 0.018$ GeV, after\nextrapolation to the continuum limit and in the quenched approximation.",
        "positive": "Approximate Ginsparg-Wilson fermions: A first test: We construct a 4-d lattice Dirac operator D using a systematical expansion in\nterms of simple operators on the lattice. The Ginsparg-Wilson equation turns\ninto a system of coupled equations for the expansion coefficients of D. We\nsolve these equations for a finite parametrization of D and find an approximate\nsolution of the Ginsparg-Wilson equation. We analyze the spectral properties of\nour D for various ensembles of quenched SU(3) configurations. Improving the\ngauge field action considerably improves the spectral properties of our D."
    },
    {
        "anchor": "Instantaneous interquark potential in generalized Landau gauge in SU(3)\n  lattice QCD: a possible gauge for the quark potential model: We investigate \"instantaneous interquark potential\", an interesting\ngauge-dependent quantity defined from the spatial correlator $<\\mathrm{Tr}\n[U_4^\\dagger(s)U_4(s')]>$ of the temporal link-variable $U_4$, in detail in\ngeneralized Landau gauge using SU(3) quenched lattice QCD. While the\ninstantaneous potential has no linear part in the Landau gauge, in the Coulomb\ngauge, it is expressed by the Coulomb plus linear potential, where the slope is\n2-3 times larger than the physical string tension, and the lowest energy state\nis considered to be a gluon-chain state. Using the generalized Landau gauge, we\nfind that the instantaneous potential can be continuously described between the\nLandau and the Coulomb gauges, and it approximately reproduces the physical\ninterquark potential in a specific intermediate gauge, which we call\n\"$\\lambda_C$-gauge\". This $\\lambda_C$-gauge is expected to provide a\nquark-potential-model picture, where dynamical gluons do not appear. We also\ninvestigate $T$-length terminated Polyakov-line correlator and its\ncorresponding \"finite-time potential\" in generalized Landau gauge.",
        "positive": "Charmed and light pseudoscalar meson decay constants from four-flavor\n  lattice QCD with physical light quarks: We compute the leptonic decay constants $f_{D^+}$, $f_{D_s}$, and $f_{K^+}$,\nand the quark-mass ratios $m_c/m_s$ and $m_s/m_l$ in unquenched lattice QCD\nusing the experimentally determined value of $f_{\\pi^+}$ for normalization. We\nuse the MILC highly improved staggered quark (HISQ) ensembles with four\ndynamical quark flavors---up, down, strange, and charm---and with both physical\nand unphysical values of the light sea-quark masses. The use of physical pions\nremoves the need for a chiral extrapolation, thereby eliminating a significant\nsource of uncertainty in previous calculations. Four different lattice spacings\nranging from $a\\approx 0.06$ fm to $0.15$ fm are included in the analysis to\ncontrol the extrapolation to the continuum limit. Our primary results are\n$f_{D^+} = 212.6(0.4)({}^{+1.0}_{-1.2})\\ \\mathrm{MeV}$, $f_{D_s} =\n249.0(0.3)({}^{+1.1}_{-1.5})\\ \\mathrm{MeV}$, and $f_{D_s}/f_{D^+} =\n1.1712(10)({}^{+29}_{-32})$, where the errors are statistical and total\nsystematic, respectively. The errors on our results for the charm decay\nconstants and their ratio are approximately two to four times smaller than\nthose of the most precise previous lattice calculations. We also obtain\n$f_{K^+}/f_{\\pi^+} = 1.1956(10)({}^{+26}_{-18})$, updating our previous result,\nand determine the quark-mass ratios $m_s/m_l = 27.35(5)({}^{+10}_{-7})$ and\n$m_c/m_s = 11.747(19)({}^{+59}_{-43})$. When combined with experimental\nmeasurements of the decay rates, our results lead to precise determinations of\nthe CKM matrix elements $|V_{us}| = 0.22487(51) (29)(20)(5)$,\n$|V_{cd}|=0.217(1) (5)(1)$ and $|V_{cs}|= 1.010(5)(18)(6)$, where the errors\nare from this calculation of the decay constants, the uncertainty in the\nexperimental decay rates, structure-dependent electromagnetic corrections, and,\nin the case of $|V_{us}|$, the uncertainty in $|V_{ud}|$, respectively."
    },
    {
        "anchor": "Absence of confinement in the absence of vortices: We consider the Wilson loop expectation in SU(2) lattice gauge theory in the\npresence of constraints. The constraints eliminate from the functional measure\ngauge field configurations whose physical interpretation is that of thick\ncenter vortices linking with the loop. We give a simple proof that, for\ndimension $d \\geq 3$, the so constrained Wilson loop follows perimeter law,\ni.e. non-confining behavior, at weak coupling (low temperature). Thus the\npresence of vortex configurations is a necessary condition for confinement.",
        "positive": "No confinement without Coulomb confinement: We compare the physical potential $V_D(R)$ of an external quark-antiquark\npair in the representation $D$ of SU(N), to the color-Coulomb potential $V_{\\rm\ncoul}(R)$ which is the instantaneous part of the 44-component of the gluon\npropagator in Coulomb gauge, $D_{44}(\\vx,t) = V_{\\rm coul}(|\\vx|) \\delta(t)$ +\n(non-instantaneous). We show that if $V_D(R)$ is confining, $\\lim_{R \\to\n\\infty}V_D(R) = + \\infty$, then the inequality $V_D(R) \\leq - C_D V_{\\rm\ncoul}(R)$ holds asymptotically at large $R$, where $C_D > 0$ is the Casimir in\nthe representation $D$. This implies that $ - V_{\\rm coul}(R)$ is also\nconfining."
    },
    {
        "anchor": "Towards studying the structural differences between the pion and its\n  radial excitation: We present an exploratory lattice QCD investigation of the differences\nbetween the valence quark structure of pion and its radial excitation\n$\\pi(1300)$ in a fixed finite volume using the leading-twist factorization\napproach. We present evidences that the first pion excitation in our lattice\ncomputation is a single particle state that is likely to be the finite volume\nrealization of $\\pi(1300)$. An analysis with reasonable priors result in better\nestimates of the excited state PDF and the moments, wherein we find evidence\nthat the radial excitation of pion correlates with an almost two-fold increase\nin the momentum fraction of valence quarks. This proof-of-principle work\nestablishes the viability of future lattice computations incorporating larger\noperator basis that can resolve the structural changes accompanying hadronic\nexcitation.",
        "positive": "Conformal dimensions in the large charge sectors at the O(4)\n  Wilson-Fisher fixed point: We study the O(4) Wilson-Fisher fixed point in 2+1 dimensions in fixed\nlarge-charge sectors identified by products of two spin-j representations\n$(j_L, j_R)$. Using effective field theory we derive a formula for the\nconformal dimensions $D(j_L, j_R)$ of the leading operator in terms of two\nconstants, $c_{3/2}$ and $c_{1/2}$, when the sum $j_L + j_R$ is much larger\nthan the difference $|j_L-j_R|$. We compute $D(j_L,j_R)$ when $j_L = j_R$ with\nMonte Carlo calculations in a discrete formulation of the O(4) lattice field\ntheory, and show excellent agreement with the predicted formula and estimate\n$c_{3/2}=1.068(4)$ and $c_{1/2}=0.083(3)$."
    },
    {
        "anchor": "Antiferromagnetic Potts Models on the Square Lattice: We study the antiferromagnetic $q$-state Potts model on the square lattice\nfor $q=3$ and $q=4$, using the Wang-Swendsen-Koteck\\'y Monte Carlo algorithm\nand a new finite-size-scaling extrapolation method. For $q=3$ we obtain good\ncontrol up to correlation length $\\xi \\sim 5000$; the data are consistent with\n$\\xi(\\beta) = A e^{2\\beta} \\beta (1 + a_1 e^{-\\beta} + \\ldots)$ as\n$\\beta\\to\\infty$. For $q=4$ the model is disordered even at zero temperature.",
        "positive": "First studies of the phase diagram of N=1 supersymmetric Yang-Mills\n  theory: The behavior of supersymmetric theories at finite temperatures differs from\nthat of other theories in certain aspects. Due to the different thermal\nstatistics of bosons and fermions, supersymmetry is explicitly broken for any\nnon-zero value of the temperature. We study N=1 supersymmetric Yang-Mills\ntheory on the lattice at finite temperatures. This model is the simplest\nsupersymmetric extension of the pure gauge sector of QCD, describing the\ninteractions between gluons and their fermionic superpartners, the gluinos. At\nzero temperature the theory confines like QCD, and chiral symmetry is\nspontaneously broken. At high temperatures, deconfinement and chiral symmetry\nrestoration are expected to take place, but it is not known whether these two\nphase transitions coincide or not. First results on this topic, obtained in\nnumerical simulations on the lattice, will be presented and discussed."
    },
    {
        "anchor": "New tests of the gauge-fixing approach to lattice chiral gauge theories: We report on recent progress with the gauge-fixing approach to lattice chiral\ngauge theories. The bosonic sector of the gauge-fixing approach is studied with\nfully dynamical U(1) gauge fields. We demonstrate that it is important to\nformulate the Lorentz gauge-fixing action such that the dense set of lattice\nGribov copies is removed, and the gauge-fixing action has a unique absolute\nminimum. We then show that the spectrum in the continuum limit contains only\nthe desired massless photon, as expected.",
        "positive": "Recent Progress in Lattice QCD Thermodynamics: This review gives a critical assessment of the current state of lattice\nsimulations of QCD thermodynamics and what it teaches us about hot hadronic\nmatter. It outlines briefly lattice methods for studying QCD at nonzero\ntemperature and zero baryon number density with particular emphasis on\nassessing and reducing cutoff effects. It discusses a variety of difficulties\nwith methods for determining the transition temperature. It uses results\nreported recently in the literature and at this conference for illustration,\nespecially those from a major study carried out by the HotQCD collaboration."
    },
    {
        "anchor": "Effects of the disconnected flavor singlet corrections on the hyperfine\n  splitting in charmonium: Experimentally the charmonium hyperfine splitting is\n$M_{J/\\psi}-M_{\\eta_c}=117$ MeV and current lattice results are generally below\nthis value. The difference could be due to the effects of the disconnected\nflavor singlet diagrams which have not been included in these calculations.\nPrevious attempts to determine the disconnected flavor singlet corrections have\nled just to rough estimates in the range of $\\pm 20$ MeV. We present\npreliminary results for these corrections calculated on fine ($a\\approx 0.09$\nfm) Asqtad 2+1 flavor lattices provided by the MILC Collaboration.",
        "positive": "Extraction of $B_s \\to D^{(*)}_s$ form factors from ${ N_f}=2$ lattice\n  QCD: We report on a two-flavour lattice QCD study of the $B_s \\to D_s$ and $B_s\n\\to D^*_s$ transitions parameterized, in the heavy quark limit, by the form\nfactors ${\\cal G}$, and $h_{A_1}$, $h_{A_2}$ and $h_{A_3}$, respectively. In\nthe search for New Physics through tests of lepton flavour universality, $B_s$\ndecay channels are complementary to the $B$ decays widely studied at $B$\nfactories and LHCb, while on the theory side they can be better controlled than\nthe $B_c$ and $\\Lambda_b$ decays. The purpose of this exploratory two-flavour\nstudy is, in preparation for future analyses of lattice QCD simulations with\n${N_f>2}$ and physical quark-masses, to gain experience on a suitable method\nfor a lattice extraction of form factors associated with $b \\to c$ currents\nthat may yield tighter control over systematic effects like contamination from\nexcited states and cut-off effects. We obtain the zero-recoil values ${\\cal\nG}^{B_s \\to D_s}(1)=1.03(14)$ and $h^{B_s \\to D^*_s}(1)=0.85(16)$."
    },
    {
        "anchor": "S-parameter and pseudo-Nambu-Goldstone boson mass from lattice QCD: We present a lattice calculation of $L_{10}$, one of the low energy constants\nin Chiral Perturbation Theory, and the charged-neutral pion squared mass\nsplitting, using dynamical overlap fermion. Exact chiral symmetry of the\noverlap fermion allows us to reliably extract these quantities from the\ndifference of the vacuum polarization functions for vector and axial-vector\ncurrents. In the context of the technicolor models, these two quantities are\nread as the $S$-parameter and the pseudo-Nambu-Goldstone boson mass\nrespectively, and play an important role in discriminating the models from\nothers. This calculation can serve as a feasibility study of the lattice\ntechniques for more general technicolor gauge theories.",
        "positive": "CORE Technology and Exact Hamiltonian Real-Space Renormalization Group\n  Transformations: The COntractor REnormalization group (CORE) method, a new approach to solving\nHamiltonian lattice systems, is presented. The method defines a systematic and\nnonperturbative means of implementing Kadanoff-Wilson real-space\nrenormalization group transformations using cluster expansion and contraction\ntechniques. We illustrate the approach and demonstrate its effectiveness using\nscalar field theory, the Heisenberg antiferromagnetic chain, and the\nanisotropic Ising chain. Future applications to the Hubbard and t-J models and\nlattice gauge theory are discussed."
    },
    {
        "anchor": "Heavy-Light Decay Constants with Dynamical Gauge Configurations and\n  Wilson or Improved Valence Quark Action: We describe a calculation of heavy-light decay constants including virtual\nquark loop effects. We have generated dynamical gauge configurations at three\n$\\beta$ values using two flavors of Kogut-Susskind quarks with a range of\nmasses. These are analyzed with a Wilson valence quark action. Preliminary\nresults based on a ``fat-link'' clover valence quark action are also reported.\nResults from the two methods differ by 30 to 50 MeV, which is presumably due to\nsignificant - but as yet unobserved - lattice spacing dependence in one or both\nof the approaches.",
        "positive": "Determination of Lee-Yang edge singularities in QCD by rational\n  approximations: We report updated results on the determination of Lee-Yang edge (LYE)\nsingularities in $N_f = 2+1$ QCD using highly improved staggered quarks (HISQ)\nwith physical masses on $N_\\tau = 4, 6, 8$ lattices. The singularity structure\nof QCD in the complex $\\mu_B$ plane is probed using conserved charges\ncalculated at imaginary $\\mu_B$. The location of the singularities is\ndetermined by studying the (uncancelled) poles of multi-point Pad\\'e\napproximants. We show that close to the Roberge-Weiss (RW) transition, the\nlocation of the LYE singularities scales according to the $3$-$d$ $Z(2)$\nuniversality class. By combining the new $N_\\tau = 6$ data with the $N_\\tau =\n4$ data from our previous analysis we extract a rough estimate for the RW\ntemperature in the continuum limit. We also discuss some preliminary results\nfor the singularities close to the chiral phase transition obtained from\nsimulations on $N_\\tau = 6, 8$ lattices."
    },
    {
        "anchor": "Dimensional reduction from five-dimensional gauge theories: We study the phase diagram of five-dimensional SU(2) gauge theories on\nanisotropic lattices with periodic boundary conditions. We locate a line of\nfirst order bulk phase transitions and second order phase transitions related\nto breaking of the center along one direction. A reduction to four dimensions\noccurs through compactification of one dimension but not only. By choosing a\nlattice spacing in the extra dimension larger than in the other dimensions, we\nfind hints that the hyperplanes orthogonal to the extra dimension decouple from\neach other. Our analysis is based on measurements of Polyakov loops, the static\npotential extracted from Wilson loops and renormalized couplings defined\nthrough the static force and its derivative.",
        "positive": "Lattice Gauge Fields Topology Uncovered by Quaternionic sigma-model\n  Embedding: We investigate SU(2) gauge fields topology using new approach, which exploits\nthe well known connection between SU(2) gauge theory and quaternionic\nprojective sigma-models and allows to formulate the topological charge density\nentirely in terms of sigma-model fields. The method is studied in details and\nfor thermalized vacuum configurations is shown to be compatible with\noverlap-based definition. We confirm that the topological charge is distributed\nin localized four dimensional regions which, however, are not compatible with\ninstantons. Topological density bulk distribution is investigated at different\nlattice spacings and is shown to possess some universal properties."
    },
    {
        "anchor": "On the linear increase of the flux tube thickness near the deconfinement\n  transition: We study the flux tube thickness of a generic Lattice Gauge Theory near the\ndeconfining phase transition. It is well known that the effective string model\npredicts a logarithmic increase of the flux tube thickness as a function of the\ninterquark distance for any confining LGT at zero temperature. It is perhaps\nless known that this same model predicts a linear increase in the vicinity of\nthe deconfinement transition. We present a precise derivation of this result\nand compare it with a set of high precision simulations in the case of the 3d\ngauge Ising model.",
        "positive": "Simulating lattice field theories on multiple thimbles: Simulating thimble regularization of lattice field theory can be tricky when\nmore than one thimble is to be taken into account. A couple of years ago we\nproposed a solution for this problem. More recently this solution proved to be\neffective in the case of 0+1 dimensional QCD. A few lessons we can learnt,\nincluding the role of symmetries and general hints on algorithmic solutions."
    },
    {
        "anchor": "The chiral limit of non-compact QED(3): Non-compact QED(3) with four-component fermion flavor content larger than or\nequal to two is studied numerically near the chiral limit to understand its\nchiral symmetry breaking features. We monitor discretization and finite size\neffects on the chiral condensate by simulating the model at different values of\nthe gauge coupling on lattices ranging in size from 10^3 to 50^3. Our upper\nbound for the dimensionless condensate beta^2<psibarpsi> in the N_f=2 case is\n5x10^{-5}.",
        "positive": "The QCD crossover at zero and non-zero baryon densities from Lattice QCD: We map out the QCD crossover line $\\frac{T_c(\\mu_B)}{T_c(0)} = 1 - \\kappa_2\n\\left( \\frac{\\mu_B}{T_c(0)} \\right)^2 - \\kappa_4 \\left( \\frac{\\mu_B}{T_c(0)}\n\\right)^4 + \\mathcal{O}(\\mu_B^6)$ for the first time up to\n$\\mathcal{O}(\\mu_B^4)$ for a strangeness neutral system by performing a Taylor\nexpansion of chiral observables in temperature $T$ and chemical potentials\n$\\mu$. At vanishing chemical potential, we report a crossover temperature\n$T_c(0) = (156.5 \\pm 1.5)\\;\\mathrm{MeV}$ defined by the average of several\nsecond-order chiral susceptibilities. For a system with thermal conditions\nappropriate for a heavy-ion collision, we determined a curvature from the\nsubtracted condensate as $\\kappa_2 = 0.0120(20)$ and from the disconnected\nsusceptibility as $\\kappa_2 = 0.0123(30)$. The next order $\\kappa_4$ is\nsignificantly smaller. We also report the crossover temperature as a function\nof the chemical potentials for: baryon-number, electric charge, strangeness and\nisospin. Additionally, we find that $T_c(\\mu_B)$ is in agreement with lines of\nconstant energy density and constant entropy density. Along this crossover\nline, we study net baryon-number fluctuations and show that their increase is\nsubstantially smaller compared to that obtained in HRG model calculations.\nSimilarly, we analyze chiral susceptibility fluctuations along the crossover\nline and show that these are constant. We conclude that no signs for a\nnarrowing of the crossover region can be found for baryon chemical potential\n$\\mu_B < 250\\;\\mathrm{MeV}$."
    },
    {
        "anchor": "Lattice QCD calculation of form factors describing the rare decays $B\n  \\to K^* \\ell^+ \\ell^-$ and $B_s \\to \u03c6\\ell^+ \\ell^-$: The rare decays $B^0 \\to K^{*0} \\mu^+ \\mu^-$ and $B_s \\to \\phi \\mu^+ \\mu^-$\nare now being observed with enough precision to test Standard Model\npredictions. A full understanding of these decays requires accurate\ndeterminations of the corresponding hadronic form factors. Here we present\nresults of lattice QCD calculations of the $B \\to K^*$ and $B_s \\to \\phi$ form\nfactors; we also determine the form factors relevant for the tree-level decays\n$B_s \\to K^* \\ell \\nu$. We use full-QCD configurations including 2+1 flavors of\nsea quarks using an improved staggered action, and we employ lattice\nnon-relativistic QCD to describe the bottom quark.",
        "positive": "The $\u039b(1405)$ from Lattice QCD: Determining the Finite-volume\n  Spectra: This work presents technical details of determining the finite-volume energy\nspectra for the scattering amplitude of the coupled-channel $\\pi\\Sigma -\n\\bar{K}N$ from lattice QCD data. The importance of reliably extracting such\nspectra lies in the crucial dependence of the hadronic scattering amplitudes\nanalysis on the energy spectrum when using L\\\"{u}scher's formalism. Results of\nthe methods used are presented and the final finite-volume spectra are shown.\nThe analysis of the scattering amplitude based on these results, exhibits a\ntwo-pole structure for the $\\Lambda(1405)$, a virtual bound state below the\n$\\pi\\Sigma$ threshold and a resonance pole right below the $\\bar{K}N$\nthreshold."
    },
    {
        "anchor": "K^+ -> pi^+ pi^0 Decays on Finite Volumes and at Next-to-Leading Order\n  in the Chiral Expansion: We present the ingredients necessary for the determination of physical K->pi\npi decay amplitudes for Delta I=3/2 transitions, from lattice simulations at\nunphysical kinematics and the use of chiral perturbation theory at\nnext-to-leading order. In particular we derive the expressions for the matrix\nelements <pi pi(I=2)|O_W|K>, where O_W is one of the operators appearing in the\nDelta S=1 weak Hamiltonian, in terms of low-energy constants at next-to-leading\norder in the chiral expansion. The one-loop chiral corrections are evaluated\nfor arbitrary masses and momenta, both in full QCD and in the quenched\napproximation. We also investigate the finite-volume effects in this procedure.",
        "positive": "Strings, quantum gravity and non-commutative geometry on the lattice: I review recent progress in understanding non-perturbative aspects of string\ntheory, quantum gravity and non-commutative geometry using lattice methods."
    },
    {
        "anchor": "Application of heavy-quark effective theory to lattice QCD: I. Power\n  Corrections: Heavy-quark effective theory (HQET) is applied to lattice QCD with Wilson\nfermions at fixed lattice spacing a. This description is possible because\nheavy-quark symmetries are respected. It is desirable because the ultraviolet\ncutoff $1/a$ in current numerical work and the heavy-quark mass $m_Q$ are\ncomparable. Effects of both short distances, a and $1/m_Q$, are captured fully\ninto coefficient functions, which multiply the operators of the usual HQET.\nStandard tools of HQET are used to develop heavy-quark expansions of lattice\nobservables and, thus, to propagate heavy-quark discretization errors. Three\nexplicit examples are given: namely, the mass, decay constant, and semileptonic\nform factors of heavy-light mesons.",
        "positive": "The chirally rotated Schr\u00f6dinger functional: theoretical expectations\n  and perturbative tests: The chirally rotated Schr\\\"odinger functional ($\\chi$SF) with massless\nWilson-type fermions provides an alternative lattice regularization of the\nSchr\\\"odinger functional (SF), with different lattice symmetries and a common\ncontinuum limit expected from universality. The explicit breaking of flavour\nand parity symmetries needs to be repaired by tuning the bare fermion mass and\nthe coefficient of a dimension 3 boundary counterterm. Once this is achieved\none expects the mechanism of automatic O($a$) improvement to be operational in\nthe $\\chi$SF, in contrast to the standard formulation of the SF. This is\nexpected to significantly improve the attainable precision for step-scaling\nfunctions of some composite operators. Furthermore, the $\\chi$SF offers new\nstrategies to determine finite renormalization constants which are\ntraditionally obtained from chiral Ward identities. In this paper we consider a\ncomplete set of fermion bilinear operators, define corresponding correlation\nfunctions and explain the relation to their standard SF counterparts. We\ndiscuss renormalization and O($a$) improvement and then use this set-up to\nformulate the theoretical expectations which follow from universality.\nExpanding the correlation functions to one-loop order of perturbation theory we\nthen perform a number of non-trivial checks. In the process we obtain the\naction counterterm coefficients to one-loop order and reproduce some known\nperturbative results for renormalization constants of fermion bilinears. By\nconfirming the theoretical expectations, this perturbative study lends further\nsupport to the soundness of the $\\chi$SF framework and prepares the ground for\nnon-perturbative applications."
    },
    {
        "anchor": "Adjoint Wilson Line in SU(2) Lattice Gauge Theory: The behavior of the adjoint Wilson line in finite-temperature, $SU(2)$,\nlattice gauge theory is discussed. The expectation value of the line and the\nassociated excess free energy reveal the response of the finite-temperature\ngauge field to the presence of an adjoint source. The value of the adjoint line\nat the critical point of the deconfining phase transition is highlighted. This\nis not calculable in weak or strong coupling. It receives contributions from\nall scales and is nonanalytic at the critical point. We determine the general\nform of the free energy. It includes a linearly divergent term that is\nperturbative in the bare coupling and a finite, nonperturbative piece. We use a\nsimple flux tube model to estimate the value of the nonperturbative piece. This\nprovides the normalization needed to estimate the behavior of the line as one\nmoves along the critical curve into the weak coupling region.",
        "positive": "Axial Nucleon form factors from lattice QCD: We present results on the nucleon axial form factors within lattice QCD using\ntwo flavors of degenerate twisted mass fermions. Volume effects are examined\nusing simulations at two volumes of spatial length $L=2.1$ fm and $L=2.8$ fm.\nCut-off effects are investigated using three different values of the lattice\nspacings, namely $a=0.089$ fm, $a=0.070$ fm and $a=0.056$ fm. The nucleon axial\ncharge is obtained in the continuum limit and chirally extrapolated to the\nphysical pion mass enabling comparison with experiment."
    },
    {
        "anchor": "Renormalization constants for $N_{\\rm f}=2+1+1$ twisted mass QCD: We summarize recent non-perturbative results obtained for the renormalization\nconstants computed in the RI'-MOM scheme for $N_{\\rm f}=2+1+1$ twisted mass\nQCD. Our implementation employs the Iwasaki gauge action and four dynamical\ndegenerate twisted mass fermions. Renormalization constants for scalar,\npseudo-scalar, vector and axial operators, as well as the quark propagator\nrenormalization, are computed at three different values of the lattice spacing,\ntwo different volumes and several values of the twisted mass. Our method allows\nfor a precise cross-check of the running, because of the particular proper\ntreatment of the hypercubic artifacts. Preliminary results for twist-2\noperators are also presented.",
        "positive": "Scattering length from BS wave function inside the interaction range: We evaluate $I=2$ two-pion scattering length through the scattering amplitude\nobtained by the Bethe-Salpeter wave function inside the interaction range. The\nscattering length is computed with $m_\\pi = 0.52-0.86$ GeV in the quenched\nlattice QCD. Furthermore, the half-off-shell amplitude is calculated, from\nwhich the effective range is extracted. Our results are compared with those by\nthe conventional finite size method and by chiral perturbation theory to\nconfirm consistency."
    },
    {
        "anchor": "Higher-twist contributions to the Structure Functions coming from\n  4-fermion operators: We evaluate the contribution of a class of higher-twist operators to the\nlowest moment of the Structure Functions, by computing appropriate matrix\nelements of six four-fermion operators in the quenched approximation. Their\nperturbative renormalization constants and mixing coefficients are calculated\nin the 't Hooft-Veltman scheme of dimensional regularization, using codes\nwritten in the algebraic manipulation computer language FORM.",
        "positive": "The running coupling of QCD with four flavors: We have calculated the step scaling function and the running coupling of QCD\nin the Schroedinger functional scheme with four flavors of O(a) improved Wilson\nquarks. Comparisons of our non-perturbative results with 2-loop and 3-loop\nperturbation theory as well as with non-perturbative data for only two flavors\nare made."
    },
    {
        "anchor": "G_2 gauge theory at finite temperature: The gauge group being centreless, $G_2$ gauge theory is a good laboratory for\nstudying the role of the centre of the group for colour confinement in\nYang-Mills gauge theories. In this paper, we investigate $G_2$ pure gauge\ntheory at finite temperature on the lattice. By studying the finite size\nscaling of the plaquette, the Polyakov loop and their susceptibilities, we show\nthat a deconfinement phase transition takes place. The analysis of the\npseudocritical exponents give strong evidence of the deconfinement transition\nbeing first order. Implications of our findings for scenarios of colour\nconfinement are discussed.",
        "positive": "Transfer matrix and nonperturbative renormalization of fermionic\n  currents in lattice QCD: The functional integral representation for fermionic observables on the\nlattice is studied. In particular, Grassmannian representations of the scalar\n$\\hatJ^{(S)}$ and pseudoscalar $\\hatJ^{(P)}$ currents and pseudoscalar\ncorrelator are derived. It is also discussed the connection between the\nfermionic Fock space and boundary conditions along the time direction."
    },
    {
        "anchor": "Tata lectures on overlap fermions: Overlap formalism deals with the construction of chiral gauge theories on the\nlattice. These set of lectures provide a pedagogical introduction to the\nsubject with emphasis on chiral anomalies and gauge field topology. Subtleties\nassociated with the generating functional for gauge theories coupled to chiral\nfermions are discussed.",
        "positive": "Lattice study on two-color QCD with six flavors of dynamical quarks: We study the dynamics of SU(2) gauge theory with NF=6 Dirac fermions by means\nof lattice simulation to investigate if they are appropriate to realization of\nelectroweak symmetry breaking. The discrete analogue of beta function for the\nrunning coupling constant defined under the Schroedinger functional boundary\ncondition are computed on the lattices up to linear size of L/a=24 and preclude\nthe existence of infrared fixed point below 7.6. Gluonic observables such as\nheavy quark potential, string tension, Polyakov loop suggest that the target\nsystem is in the confining phase even in the massless quark limit."
    },
    {
        "anchor": "P-Vortices, Gauge Copies, and Lattice Size: We study the dependence of the center-projected string tension on both the\nlattice size, and the number of gauge copies used for maximal center gauge\nfixing. We show that a recent finding of Bornyakov, Komarov, Polikarpov, and\nVeselov (hep-lat/0002017), indicating a substantial breakdown of center\ndominance in maximal center gauge, is only obtained for rather small lattice\nvolumes, and is not found in numerical simulations on larger lattices. It is\nshown that center-projected Creutz ratios approach the full asymptotic string\ntension as lattice size increases, and that the P-vortex density is consistent,\nat moderately weak couplings, with 2-loop scaling behavior.",
        "positive": "Finite size dependence of scaling functions of the three-dimensional\n  O(4) model in an external field: We calculate universal finite size scaling functions for the order parameter\nand the longitudinal susceptibility of the three-dimensional O(4) model. The\nphase transition of this model is supposed to be in the same universality class\nas the chiral transition of two-flavor QCD. The scaling functions serve as a\ntesting device for QCD simulations on small lattices, where, for example,\npseudocritical temperatures are difficult to determine. In addition, we have\nimproved the infinite volume limit parametrization of the scaling functions by\nusing newly generated high statistics data for the 3d O(4) model in the high\ntemperature region on an L=120 lattice."
    },
    {
        "anchor": "Zone methods and the fermion sign problem: We review a recently proposed approach to the problem of alternating signs\nfor fermionic many body Monte Carlo simulations in finite temperature\nsimulations. We derive an estimate for fermion wandering lengths and introduce\nthe notion of permutation zones, special regions of the lattice where identical\nfermions may interchange and outside of which they may not. Using successively\nlarger permutation zones, one can extrapolate to obtain thermodynamic\nobservables in regimes where direct simulation is impossible.",
        "positive": "Variants of L\u00fcscher's fermion algorithm: We study improved variants of L\\\"uscher's algorithm, including the cases of\nstaggered fermions and finite density."
    },
    {
        "anchor": "Universality and Chaos in Quantum Field Theories: We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)\ngauge theory and in full QCD as well as in quenched U(1) theory on various\nlattice sizes. As a measure of the fluctuation properties of the eigenvalues,\nwe consider the nearest-neighbor spacing distribution, $P(s)$. We further study\ntwo-color QCD at nonzero chemical potential, $\\mu$, by constructing the spacing\ndistribution of adjacent eigenvalues in the complex plane. We find that in all\nregions of their phase diagrams, compact lattice gauge theories have bulk\nspectral correlations given by random matrix theory, which is an indication for\nquantum chaos. In the confinement phase, the low-lying Dirac spectrum of these\nquantum field theories is well described by random matrix theory, exhibiting\nuniversal behavior.",
        "positive": "The First Calculation for the Mass of the Ground $4^{++}$ Glueball State\n  on Lattice: Under the quenched approximation, we perform a lattice calculation for the\nmass of the ground $4^{++}$ glueball state in $E^{++}$ channel on a $D=3+1$\nlattice. Our calculation shows that the mass of this state is\n$M_G(4^{++})=3.65(6)(18)GeV$, which rules out the $4^{++}$ or mainly $4^{++}$\nglueball interpretation for $\\xi(2230)$."
    },
    {
        "anchor": "Low Energy Chiral Lagrangian Parameters for Scalar and Pseudoscalar\n  Mesons: We present results of a high-statistics study of scalar and pseudoscalar\nmeson propagators in quenched QCD at two values of lattice spacing, beta = 5.7\nand 5.9, with clover-improved Wilson fermions. The study of the chiral limit is\nfacilitated by the pole-shifting ansatz of the modified quenched approximation.\nPseudoscalar masses and decay constants are determined as a function of quark\nmass and quenched chiral log effects are estimated. A study of the flavor\nsinglet eta prime hairpin diagram yields a precise determination of the eta\nprime mass insertion. The corresponding value of the quenched chiral log\nparameter delta is compared with the observed QCL effects. Removal of QCL\neffects from the scalar propagator allows a determination of the mass of the\nlowest lying isovector scalar $q\\bar{q}$ meson.",
        "positive": "Stripes from (noncommutative) stars: We show that lattice regularization of noncommutative field theories can be\nused to study non-perturbative vacuum phases. Specifically we provide evidence\nfor the existence of a striped phase in two-dimensional noncommutative scalar\nfield theory"
    },
    {
        "anchor": "Proposal for Topologically Unquenched QCD: A proposal is presented for simulating an improvement on quenched QCD with\ndynamical fermions which interact with the gluon configuration only via the\ntopological index of the latter. Strengths and shortcomings of the method are\ndiscussed and it is argued that the approximation - though being crude - shares\nsome qualitative aspects of full QCD which relate to the issue of chiral\nsymmetry breaking.",
        "positive": "Phase transition strengths from the density of partition function zeroes: We report on a new method to extract thermodynamic properties from the\ndensity of partition function zeroes on finite lattices. This allows direct\ndetermination of the order and strength of phase transitions numerically.\nFurthermore, it enables efficient distinguishing between first- and\nsecond-order transitions, elucidates crossover between them and illuminates the\norigins of finite-size scaling. The power of the method is illustrated in\ntypical applications for both Fisher and Lee-Yang zeroes."
    },
    {
        "anchor": "Long distance contributions to the rare kaon decay\n  $K\\to\u03c0\\ell^{+}\\ell^{-}$: The rare decays of a kaon into a pion and a charged lepton/antilepton pair\nproceed via a flavour changing neutral current and therefore may only be\ninduced beyond tree level in the Standard Model. This natural suppression makes\nthese decays sensitive to the effects of potential New Physics. To discern such\nNew Physics one must be able to control the errors on the Standard Model\nprediction of the decay amplitude. These particular decay channels however are\ndominated by a single photon exchange; this involves a sizeable long-distance\nhadronic contribution which represents the current major source of theoretical\nuncertainty. Here we outline our methodology for the computation of the long\ndistance contributions to these rare decay amplitudes using lattice QCD, and\npresent the numerical results of some exploratory studies using the Domain Wall\nFermion ensembles of the RBC and UKQCD collaborations.",
        "positive": "Large-N_f behavior of the Yukawa model: analytic results: We investigate the Yukawa model in which $N_f$ fermions are coupled with a\nscalar field $\\phi$ through a Yukawa interaction. The phase diagram is rather\nwell understood. If the fermions are massless, there is a chiral transition at\n$T_c$: for $T < T_c$ chiral symmetry is spontaneously broken. At $N_f=\\infty$\nthe transition is mean-field like, while, for any finite $N_f$, standard\narguments predict Ising behavior. This apparent contradiction has been\nexplained by Kogut et al., who showed by scaling arguments and Monte Carlo\nsimulations that in the large-$N_f$ limit the width of the Ising critical\nregion scales as a power of $1/N_f$, so that only mean-field behavior is\nobserved for $N_f$ strictly equal to infinity. We will show how the results of\nKogut et al. can be recovered analytically in the framework of a generalized\n$1/N_f$ expansion. The method we use is a simple generalization of the method\nwe have recently applied to a two-dimensional generalized Heisenberg model."
    },
    {
        "anchor": "BSM Kaon Mixing at the Physical Point: We present a progress update on the calculation of beyond the standard model\n(BSM) kaon mixing matrix elements at the physical point. Simulations are\nperformed using 2+1 flavour domain wall lattice QCD with the Iwasaki gauge\naction at 3 lattice spacings and with pion masses ranging from 430 MeV to the\nphysical pion mass.",
        "positive": "Improving center vortex detection by usage of center regions as guidance\n  for the direct maximal center gauge: The center vortex model of quantum chromodynamic states that vortices, closed\ncolor-magnetic flux, percolate the vacuum. Vortices are seen as the relevant\nexcitations of the vacuum, causing confinement and dynamical chiral symmetry\nbreaking. In an appropriate gauge, as \\textit{direct maximal center gauge},\nvortices are detected by projecting onto the center degrees of freedom. Such\ngauges suffer from Gribov copy problems: different local maxima of the\ncorresponding gauge functional can result in different predictions of the\nstring tension. By using non-trivial center regions, that is, regions whose\nboundary evaluates to a non-trivial center element, a resolution of this issue\nseems possible. We use such non-trivial center regions to guide simulated\nannealing procedures, preventing an underestimation of the string tension in\norder to resolve the Gribov copy problem."
    },
    {
        "anchor": "The Integrable Bootstrap Program at Large N and its Applications in\n  Gauge Theory: We present results for the large-$N$ limit of the (1+1)-dimensional principal\nchiral sigma model. This is an asymptotically-free $N\\times N$ matrix-valued\nfield with massive excitations. All the form factors and the exact correlation\nfunctions of the Noether-current operator and the energy-momentum tensor are\nfound, from Smirnov's form-factor axioms. We consider (2+1)-dimensional\n$SU(\\infty)$ Yang-Mills theory as an array of principal chiral models with a\ncurrent-current interaction. We discuss how to use our new form factors to\ncalculate physical quantities in this gauge theory.",
        "positive": "Properties of QCD vacuum from lattice: A disorder parameter is constructed which signals the condensation of\nvortices. The construction is tested by numerical simulations. Advances in the\nunderstanding of the basic properties of QCD vacuum will be reported. Three\nmain subjects will be touched: 1) Condensation of monopoles and confinement. 2)\nTopology, or instanton physics. 3) Gauge invariant field strength correlators,\nand their behaviour across the deconfining phase transition."
    },
    {
        "anchor": "Three relativistic neutrons in a finite volume: We generalize the relativistic field-theoretic (RFT) three-particle\nfinite-volume formalism to systems of three identical, massive, spin-$1/2$\nfermions, such as three neutrons. This allows, in principle, for the\ndetermination of the three-neutron interaction from the finite-volume spectrum\nof three-neutron states, which can be obtained from lattice QCD calculations.",
        "positive": "Approximate dual representation for Yang-Mills SU(2) gauge theory: An approximate dual representation for non-Abelian lattice gauge theories in\nterms of a new set of dynamical variables, the plaquette occupation numbers\n(PONs) that are natural numbers, is discussed. They are the expansion indices\nof the local series of the expansion of the Boltzmann factors for every\nplaquette of the Yang-Mills action. After studying the constraints due to gauge\nsymmetry, the SU(2) gauge theory is solved using Monte Carlo simulations. For a\nPONs configuration the weight factor is given by Haar-measure integrals over\nall links whose integrands are products of powers of plaquettes. Herein,\nupdates are limited to changes of the PON at a plaquette or all PONs on a\ncoordinate plane. The Markov chain transition probabilities are computed\nemploying truncated maximal trees and the Metropolis algorithm. The algorithm\nperformance is investigated with different types of updates for the plaquette\nmean value over a large range of $\\beta$s. Using a $12^4$ lattice very good\nagreement with a conventional heath bath algorithm is found for the strong and\nweak coupling limits. Deviations from the latter being below 0.1% for $2.5 <\n\\beta < 3$. The mass of the lightest $J^{PC}=0^{++}$ glueball is evaluated and\nreproduces the results found in the literature."
    },
    {
        "anchor": "A note on ultraviolet suppressed quasi-optimal domain wall fermions: In a recent work Chiu proposed to modify domain wall fermions that allow in\nan optimal way fewer number of flavors than in the standard case. This is done\nusing a variant of doamin wall fermions, the so-called truncated overlap\nfermions. In this note I discuss the possibility to implement his proposal for\nthe original variant of domain wall fermions. I make also some remarks on\ndynamical simulations with ultraviolet suppressed domain wall fermions.",
        "positive": "Non-perturbative Renormalization of Quark bilinears: We compute non-perturbatively the renormalization constants of quark\nbilinears on the lattice in the quenched approximation at three values of the\ncoupling beta=6/g_0^2=6.0,6.2,6.4 using both the Wilson and the tree-level\nimproved SW-Clover fermion action. We perform a Renormalization Group analysis\nat the next-to-next-to-leading order and compute Renormalization Group\ninvariant values for the constants. The results are applied to obtain a fully\nnon-perturbative estimate of the vector and pseudoscalar decay constants."
    },
    {
        "anchor": "Group Theoretical Construction of Nucleon Operators using All-to-All\n  Quark Propagators: We describe a method to construct irreducible baryon operators using\nall-to-all quark propagators. It was demonstrated earlier that a large basis of\nextended baryon operators on anisotropic, quenched lattices can be used to\nreliably extract the masses of 5 or more excited states in the nucleon channel.\nAll-to-all quark propagators are expected to be needed when studying these\nexcited states on light, dynamical configurations because contributions from\nmulti-particle states are expected to be significant. The dilution method is\nused to approximate the all-to-all quark propagators. Low-lying eigenmodes can\nalso be used if necessary. For efficient computation of matrix elements of the\ninterpolating operators, the algorithms should exploit the fact that many\nextended baryon operators can be obtained from the different linear\ncombinations of three-quark colour-singlet operators. The sparseness of the\ndiluted noise vectors also afford several computation simplifications. Some\npreliminary results are presented for nucleon effective masses.",
        "positive": "Renormalization group flow of linear sigma model with $U_A(1)$ anomaly: In the presence of finite $U_A(1)$ breaking, chiral phase transition of\nmassless two-flavor QCD is studied by tracing the renormalization group flow of\nthe corresponding effective theory. In the framework of the $\\epsilon$\nexpansion, it is found that the nature of the phase transition depends on the\ninitial condition for the parameters of the effective theory and that, when it\nundergoes second order phase transition, one of the universal exponents shows a\ndifferent value from that in the standard $O(4)$ linear sigma model. We discuss\nthat the origin of the difference is attributed to a non-decoupling effect. The\npresent status of the calculation of the effective potential is presented."
    },
    {
        "anchor": "Three fermions in a box: I calculate finite-volume effects for three identical spin-1/2 fermions in a\nbox assuming short-ranged repulsive interactions of `natural size'. This\nanalysis employs standard perturbation theory in powers of 1/L, where L^3 is\nthe volume of the box. I give results for the ground states in the A_1, T_1,\nand E cubic representations.",
        "positive": "Electromagnetic properties of doubly charmed baryons in Lattice QCD: We compute the electromagnetic properties of \\Xi_cc baryons in 2+1 flavor\nLattice QCD. By measuring the electric charge and magnetic form factors of\n\\Xi_cc baryons, we extract the magnetic moments, charge and magnetic radii as\nwell as the \\Xi_cc \\Xi_cc \\rho coupling constant, which provide important\ninformation to understand the size, shape and couplings of the doubly charmed\nbaryons. We find that the two heavy charm quarks drive the charge radii and the\nmagnetic moment of \\Xi_cc to smaller values as compared to those of, e.g., the\nproton."
    },
    {
        "anchor": "Spectrum of quenched twisted mass lattice QCD at maximal twist: Hadron masses are computed from quenched twisted mass lattice QCD for a\ndegenerate doublet of up and down quarks with the twist angle set to pi/2,\nsince this maximally twisted theory is expected to be free of linear\ndiscretization errors. Two separate definitions of the twist angle are used,\nand the hadron masses for these two cases are compared. The flavor breaking,\nthat can arise due to twisting, is discussed in the context of mass splittings\nwithin the Delta(1232) multiplet.",
        "positive": "Axial Vector Form Factors from Lattice QCD that Satisfy the PCAC\n  Relation: Previous lattice QCD calculations of axial vector and pseudoscalar form\nfactors show significant deviation from the partially conserved axial current\n(PCAC) relation between them. Since the original correlation functions satisfy\nPCAC, the observed deviations from the operator identity cast doubt on whether\nall the systematics in the extraction of form factors from the correlation\nfunctions are under control. We identify the problematic systematic as a missed\nexcited state, whose energy as a function of the momentum transfer squared,\n$Q^2$, is determined from the analysis of the 3-point functions themselves. Its\nmass is much smaller than those of the excited states previously considered and\nincluding it impacts the extraction of all the ground state matrix elements.\nThe form factors extracted using these mass/energy gaps satisfy PCAC and other\nconsistency conditions, and validate the pion-pole dominance hypothesis. We\nalso show that the extraction of the axial charge $g_A$ is very sensitive to\nthe value of the mass gaps of the excited states used and current lattice data\ndo not provide an unambiguous determination of these, unlike the $Q^2 \\neq 0$\ncase. To highlight the differences and improvement between the conventional\nversus the new analysis strategy, we present a comparison of results obtained\non a physical pion mass ensemble at $a\\approx 0.0871\\,\\mathrm{fm}$. With the\nnew strategy, we find $g_A = 1.30(6)$. A very significant improvement over\nprevious lattice results is found for the axial charge radius $r_A =\n0.74(6)\\,\\mathrm{fm}$, extracted using the $z$-expansion to parameterize the\n$Q^2$ behavior of $G_A(Q^2)$, and $g_P^\\ast = 8.06(44)$ obtained using the pion\npole-dominance ansatz to fit the $Q^2$ behavior of the induced pseudoscalar\nform factor $\\widetilde{G}_P(Q^2)$."
    },
    {
        "anchor": "Locality Properties of a New Class of Lattice Dirac Operators: A new class of lattice Dirac operators $D$ which satisfy the index theorem\nhave been recently proposed on the basis of the algebraic relation\n$\\gamma_{5}(\\gamma_{5}D) + (\\gamma_{5}D)\\gamma_{5} =\n2a^{2k+1}(\\gamma_{5}D)^{2k+2}$. Here $k$ stands for a non-negative integer and\n$k=0$ corresponds to the ordinary Ginsparg-Wilson relation. We analyze the\nlocality properties of Dirac operators which solve the above algebraic\nrelation.\n  We first show that the free fermion operator is analytic in the entire\nBrillouin zone for a suitable choice of parameters $m_{0}$ and $r$, and there\nexists a well-defined ``mass gap'' in momentum space, which in turn leads to\nthe exponential decay of the operator in coordinate space for any finite $k$.\nThis mass gap in the free fermion operator suggests that the operator is local\nfor sufficiently weak background gauge fields. We in fact establish a finite\nlocality domain of gauge field strength for\n$\\Gamma_{5}=\\gamma_{5}-(a\\gamma_{5}D)^{2k+1}$ for any finite $k$, which is\nsufficient for the cohomological analyses of chiral gauge theory. We also\npresent a crude estimate of the localization length defined by an exponential\ndecay of the Dirac operator, which turns out to be much shorter than the one\ngiven by the general Legendre expansion.",
        "positive": "Improved Hamiltonians for Quantum Simulations: Quantum simulations of lattice gauge theories for the foreseeable future will\nbe hampered by limited resources. The historical success of improved lattice\nactions in classical simulations strongly suggests that Hamiltonians with\nimproved discretization errors will reduce quantum resources, i.e. require\n$\\gtrsim 2^d$ fewer qubits in quantum simulations for lattices with $d$ spatial\ndimensions. In this work, we consider $\\mathcal{O}(a^2)$-improved Hamiltonians\nfor pure gauge theories and design the corresponding quantum circuits for its\nreal-time evolution in terms of primitive gates. An explicit demonstration for\n$\\mathbb{Z}_2$ gauge theory is presented including exploratory tests using the\nibm_perth device."
    },
    {
        "anchor": "The exact equivalence of the two-flavour strong coupling lattice\n  Schwinger model with Wilson fermions to a vertex model: In this paper a method previously employed by Salmhofer to establish an exact\nequivalence of the one-flavour strong coupling lattice Schwinger model with\nWilson fermions to some 8-vertex model is applied to the case with two\nflavours. As this method is fairly general and can be applied to strong\ncoupling QED and purely fermionic models with any (sufficiently small) number\nof Wilson fermions in any dimension the purpose of the present study is mainly\na methodical one in order to gain some further experience with it. In the paper\nthe vertex model equivalent to the two-flavour strong coupling lattice\nSchwinger model with Wilson fermions is found. It turns out to be some modified\n3-state 20-vertex model on the square lattice, which can also be understood as\na regular 6-state vertex model. In analogy with the one- flavour case, this\nmodel can be viewed as some loop model.",
        "positive": "Implementation of Simultaneous Inversion of a Multi-shifted Dirac Matrix\n  for Twisted-Mass Fermions within DD-\u03b1AMG: At physical light quark masses, efficient linear solvers are crucial for\ncarrying out the millions of inversions of the Dirac matrix required for\nobtaining high statistics in quark correlation functions. Adaptive algebraic\nmulti-grid methods have proven to be very efficient in such cases, exhibiting\nmild critical slowing down towards very light quark masses and outperforming\ntraditional solver methods, such as the conjugate gradient method, at the\nphysical point. We will discuss our implementations of simultaneous inversion\nof a (degenerate) Dirac matrix for twisted-mass fermions for multiple\nright-hand-sides (rhs) with multi-shifts and block-Krylov solvers. The\nimplementation is carried out within the community library DD$\\alpha$AMG, which\nimplements aggregation-based Domain Decomposition adaptive algebraic multi-grid\nmethods. The block-Krylov solvers are provided via the Fast Accurate Block\nLinear krylOv Solver (Fabulous) library and can be used at coarser levels. Our\ncode inverts Dirac matrices with different twisted-mass terms and for multiple\nrhs simultaneously and is thus also suitable for components within a typical\nlattice QCD simulation workflow, such as the rational approximation. We show\npreliminary results on scalability and compare the performance of our\nimplementation when using different Block-Krylov solver techniques."
    },
    {
        "anchor": "Strongly Coupled Graphene on the Lattice: The two-dimensional carbon allotrope graphene has recently attracted a lot of\nattention from researchers in the disciplines of Lattice Field Theory, Lattice\nQCD and Monte Carlo calculations. This interest has been prompted by several\nremarkable properties of the conduction electrons in graphene. For instance,\nthe conical band structure of graphene at low energies is strongly reminiscent\nof relativistic Dirac fermions. Also, due the low Fermi velocity of v_F =\nc/300, where c is the speed of light in vacuum, the physics of the conduction\nelectrons in graphene is qualitatively similar to Quantum Electrodynamics in a\nstrongly coupled regime. In turn, this opens up the prospect of the\nexperimental realization of gapped, strongly correlated states in the\nelectronic phase diagram of graphene. Here, we review the experimental and\ntheoretical motivations for Lattice Field Theory studies of graphene, and\ndescribe the directions that such research is likely to progress in during the\nnext few years. We also give a brief overview of the two main lattice theories\nof graphene, the hexagonal Hubbard theory and the low-energy Dirac theory.\nFinally, we describe the prospect of extracting response functions, such as the\nelectric conductivity, using Lattice Field Theory calculations.",
        "positive": "Exploring Correlation Methods to Determine QCD beta-Functions on the\n  Lattice: We investigate -- as an alternative to usual Monte Carlo Renormalization\nGroup methods -- the feasibility of extracting QCD beta-functions directly from\na lattice analysis of correlations between the action and Wilson loops. We test\nthis correlation technique numerically in four dimensional SU(2) gauge theory,\non a 16^4 lattice at beta = 2.5 and find very promising results."
    },
    {
        "anchor": "Non-Compact QED_3 with N_f=1 and N_f=4: We present numerical results for non-compact three-dimensional QED for\nnumbers of flavors N_f=1 and N_f=4.In particular, we address the issue of\nwhether chiral symmetry is spontaneously broken in the continuum limit, and\nobtain a positive answer for N_f=1, with a dimensionless condensate estimated\nto be beta^2<psibarpsi> ~= O(10^-3), implying that the critical number of\nflavors N_fc>1. We also compare the N_f=1 and N_f=4 models by analysing the\ntransition from strong to weak coupling behaviour using an equation of state\nbased on a continuous phase transition. While some qualitative differences\nemerge, it appears difficult to determine whether N_f=4 lies above or below\nN_fc.",
        "positive": "Topology at the Deconfinement Transition Uncovered by Inverse Blocking\n  in SU(2) Pure Gauge Theory with Fixed Point Action: Renormalization group transformations as discussed recently in deriving fixed\npoint actions are used to analyse the vacuum structure near to the\ndeconfinement temperature. Monte Carlo configurations are generated using the\nfixed point action. We compare equilibrium configurations with configurations\nobtained by inverse blocking from a coarser lattice. The absence of short range\nvacuum fluctuations in the latter does not influence the string tension. For\nthe inversely blocked configurations we find the following: (i) the topological\nsusceptibility chi_top is consistent with the phenomenological value in the\nconfinement phase, (ii) chi_top drops across the deconfinement transition,\n(iii) density and size of instantons are estimated, (iv) the topological\ndensity is found to be correlated to Abelian monopole currents and (v) the\ndensity of spacelike monopole currents becomes a confinement order parameter."
    },
    {
        "anchor": "Lattice QCD with mismatched Fermi surfaces: We study two flavor fermions with mismatched chemical potentials in quenched\nlattice QCD. We first consider a large isospin chemical potential, where a\ncharged pion is condensed, and then introduce a small mismatch between the\nchemical potentials of the up quark and the anti-down quark. We find that the\nhomogeneous pion condensate is destroyed by the mismatch of the chemical\npotentials. We also find that the two-point correlation function shows spatial\noscillation, which indicates an inhomogeneous ground state, although it is not\nmassless but massive in the present simulation setup.",
        "positive": "Specific heat and energy for the three-dimensional O(2) model: We investigate the three-dimensional O(2) model on lattices of size 8^3 to\n160^3 close to the critical point at zero magnetic field. We confirm explicitly\nthe value of the critical coupling J_c found by Ballesteros et al. and estimate\nthere the universal values of g_r and xi/L. At the critical point we study the\nfinite size dependencies of the energy density epsilon and the specific heat C.\nWe find that the nonsingular part of the specific heat C_{ns} is linearly\ndependent on 1/alpha. From the critical behaviour of the specific heat for T\nnot T_c on the largest lattices we determine the universal amplitude ratio\nA+/A-. The alpha- dependence of this ratio is close to the phenomenological\nrelation A+/A- = 1-4alpha."
    },
    {
        "anchor": "Monte Carlo Simulations of BFSS and IKKT Matrix Models: In this thesis, we studied the bosonic BFSS and IKKT matrix models using\nMonte Carlo simulations. First, we explored some toy models to check the\nvalidity of the numerical simulations. Then we simulated the BFSS matrix model\nusing Hamiltonian Monte Carlo (HMC) algorithm. In the BFSS matrix model, we\nused the Polyakov loop as an order parameter to investigate the large-N\nbehaviour of this model at different temperatures. Our simulations confirmed\nthat the model exhibits a confinement-deconfinement phase transition as the\ntemperature of the system is varied. Besides the Polyakov loop, other\nobservables such as internal energy and extent of space were also computed. In\nthe bosonic IKKT model, we studied the spontaneous symmetry breaking (SSB) of\nSO(10) symmetry using the moment of inertia tensor and found that there is no\nSSB of SO(10) symmetry in this model. Besides the eigenvalues of the moment of\ninertia tensor, other observable such as extent of spacetime was also computed.\nWe also studied the simulation theory of the phase-quenched IKKT model.",
        "positive": "Computing Nucleon Charges with Highly Improved Staggered Quarks: This work continues our program of lattice-QCD baryon physics using staggered\nfermions for both the sea and valence quarks. We present a proof-of-concept\nstudy that demonstrates, for the first time, how to calculate baryon matrix\nelements using staggered quarks for the valence sector. We show how to relate\nthe representations of the continuum staggered flavor-taste group\n$\\text{SU}(8)_{FT}$ to those of the discrete lattice symmetry group. The\nresulting calculations yield the normalization factors relating staggered\nbaryon matrix elements to their physical counterparts. We verify this\nmethodology by calculating the isovector vector and axial-vector charges $g_V$\nand $g_A$. We use a single ensemble from the MILC Collaboration with 2+1+1\nflavors of sea quark, lattice spacing $a\\approx 0.12$ fm, and a pion mass\n$M_\\pi\\approx305$ MeV. On this ensemble, we find results consistent with\nexpectations from current conservation and neutron beta decay. Thus, this work\ndemonstrates how highly-improved staggered quarks can be used for precision\ncalculations of baryon properties, and, in particular, the isovector nucleon\ncharges."
    },
    {
        "anchor": "Calculating $B_K$ using a mixed action: We present preliminary results of $B_K$ calculated using improved staggered\nfermions with the mixed action (valence quarks = HYP staggered fermions and sea\nquarks = AsqTad staggered fermions). We analyze the data based upon the\nprediction by Van de Water and Sharpe. A hint of consistency with the\nprediction is observed. We also present preliminary results of $B_8^{(3/2)}$\nand $B_7^{(3/2)}$.",
        "positive": "A finite box as a tool to distinguish free quarks from confinement at\n  high temperatures: Above the pseudocritical temperature T_c of chiral symmetry restoration a\nchiral spin symmetry (a symmetry of the color charge and of electric\nconfinement) emerges in QCD. This implies that QCD is in a confining mode and\nthere are no free quarks. At the same time correlators of operators constrained\nby a conserved current behave as if quarks were free. This explains observed\nfluctuations of conserved charges and the absence of the rho-like structures\nseen via dileptons. An independent evidence that one is in a confining mode is\nvery welcome. Here we suggest a new tool how to distinguish free quarks from a\nconfining mode. If we put the system into a finite box, then if the quarks are\nfree one necessarily obtains a remarkable diffractive pattern in the propagator\nof a conserved current. This pattern is clearly seen in a lattice calculation\nin a finite box and it vanishes in the infinite volume limit as well as in the\ncontinuum. In contrast, the full QCD calculations in a finite box show the\nabsence of the diffractive pattern implying that the quarks are confined."
    },
    {
        "anchor": "Sigma terms and strangeness content of the nucleon with $Nf=2+1+1$\n  twisted mass fermions: We investigate excited state contaminations in a direct computation of the\nnucleon $\\sigma$-terms. This is an important source of systematic effects that\nneeds to be controlled besides the light quark mass dependence and lattice\nartefacts. We use maximally twisted mass fermions with dynamical light\n($u$,$d$), strange and charm degrees of freedom. Employing an efficient\nstochastic evaluation of the disconnected contribution available for twisted\nmass fermions, we show that the effect of excited states is large in particular\nfor the strange $\\sigma$-terms, where it can be as big as $O(\\gtrsim 40%$).\nThis leads to the unfortunate conclusion that even with a source-sink\nseparation of $\\sim 1.5 \\fm$ and a good statistical accuracy it is not clear,\nwhether excited state effects are under control for this quantity.",
        "positive": "Applicability of the two-particle quantization condition to\n  partially-quenched theories: Partial quenching allows one to consider correlation functions and amplitudes\nthat do not arise in the corresponding unquenched theory. For example, physical\n$s$-wave pion scattering can be decomposed into $I=0$ and $2$ amplitudes,\nwhile, in a partially-quenched extension, the larger symmetry group implies\nthat there are more than two independent scattering amplitudes. It has been\nproposed that the finite-volume quantization condition of L\\\"uscher holds for\nthe correlation functions associated with each of the two-particle amplitudes\nthat arise in partially-quenched theories. Using partially-quenched chiral\nperturbation theory, we show that this proposal fails for those correlation\nfunctions for which the corresponding one-loop amplitudes do not satisfy\n$s$-wave unitarity. For partially-quenched amplitudes that, while being\nunphysical, do satisfy one-loop $s$-wave unitarity, we argue that the proposal\nis plausible. Implications for previous work are discussed."
    },
    {
        "anchor": "Curvature of the phase transition line in the mu-T plane: We determined the curvature of the phase transition line in the mu-T plane\nusing a Taylor expansion in mu. The Polyakov loop and the strange quark number\nsusceptibility were measured to locate the pseudocritical line. The analysis\nwas carried out on Nt=4,6,8,10 lattices generated with a Symanzik improved\ngauge and stout-link improved (2+1) flavour staggered fermion action using\nphysical quark masses.",
        "positive": "Loop, String, and Hadron Dynamics in SU(2) Hamiltonian Lattice Gauge\n  Theories: The question of how to efficiently formulate Hamiltonian gauge theories is\nexperiencing renewed interest due to advances in building quantum simulation\nplatforms. We introduce a reformulation of an SU(2) Hamiltonian lattice gauge\ntheory---a loop-string-hadron (LSH) formulation---that describes dynamics\ndirectly in terms of its loop, string, and hadron degrees of freedom, while\nalleviating several disadvantages of quantumly simulating the Kogut-Susskind\nformulation. This LSH formulation transcends the local loop formulation of\n$d+1$-dimensional lattice gauge theories by incorporating staggered quarks,\nfurnishing the algebra of gauge-singlet operators, and being used to\nreconstruct dynamics between states that have Gauss's law built in to them. LSH\noperators are then factored into products of \"normalized\" ladder operators and\ndiagonal matrices, priming them for classical or quantum information\nprocessing. Self-contained expressions of the Hamiltonian are given up to\n$d=3$. The LSH formalism makes little use of structures specific to SU(2) and\nits conceptual clarity makes it an attractive approach to apply to other\nnon-Abelian groups like SU(3)."
    },
    {
        "anchor": "Improvements for Vachaspati-Vilenkin-type Algorithms for Cosmic String\n  and Disclination Formation: We derive various consistency requirements for Vachaspati-Vilenkin type\nMonte-Carlo simulations of cosmic string formation or disclination formation in\nliquid crystals. We argue for the use of a tetrakaidekahedral lattice in such\nsimulations. We also show that these calculations can be carried out on\nlattices which are formally infinite, and do not necessitate the specification\nof any boundary conditions. This way string defects can be traced up to much\nlarger lengths than on finite lattices. The simulations then fall into a more\ngeneral class of simulations of self-interacting walks, which occupy the\nunderlying lattice very sparsely. An efficient search algorithm is essential.\nWe discuss various search strategies, and demonstrate how to implement hash\ntables with collision resolution by open addressing. The time to trace a string\ndefect is then proportional only to the string length.",
        "positive": "Investigation of the phase structure of a chirally-invariant\n  Higgs-Yukawa model: We present new data on our ongoing project on the investigation of the phase\nstructure of the Higgs-Yukawa model at large bare Yukawa couplings. The data\npresented last year are extended in terms of statistics, the number of bare\nYukawa couplings at existing, and new larger volumes. In addition, this study\nis extended by a finite temperature project at the physical top quark mass m_t\n=175 GeV and a hypothetical fourth generation top quark with a mass of m_t'\n=700 GeV ."
    },
    {
        "anchor": "Semileptonic form factor ratio B_s->D_s/B->D and its application to\n  BR(B^0_s->\u03bc^+\u03bc^-): We present a (2+1)-flavor lattice QCD calculation of the form factor ratio\nbetween the semileptonic decays $\\bar{B}^0_s \\to D^+_sl^-\\bar{\\nu} $ and\n$\\bar{B}^0 \\to D^+l^-\\bar{\\nu} $. This ratio is an important theoretical input\nto the hadronic determination of the $B$ meson fragmentation fraction ratio\n$f_s/f_d$ which enters in the measurement of $\\mathrm{BR}(B^0_s\\to\n\\mu^+\\mu^-)$. Small lattice spacings and high statistics enable us to simulate\nthe decays with a dynamic final $D$ meson of small momentum and reliably\nextract the hadronic matrix elements at nonzero recoil. We report our\npreliminary result for the form factor ratio at the corresponding momentum\ntransfer of the two decays $f_0^{(s)}(M^2_\\pi)/f_0^{(d)}(M^2_K)$.",
        "positive": "Approximate degeneracy of $J=1$ spatial correlators in high temperature\n  QCD: We study spatial isovector meson correlators in $N_f=2$ QCD with dynamical\ndomain-wall fermions on $32^3\\times 8$ lattices at temperatures $T=220-380$\nMeV. We measure the correlators of spin-one ($J=1$) operators including vector,\naxial-vector, tensor and axial-tensor. Restoration of chiral $U(1)_A$ and\n$SU(2)_L \\times SU(2)_R$ symmetries of QCD implies degeneracies in\nvector--axial-vector ($SU(2)_L \\times SU(2)_R$) and tensor--axial-tensor\n($U(1)_A$) pairs, which are indeed observed at temperatures above $T_c$.\nMoreover, we observe an approximate degeneracy of all $J=1$ correlators with\nincreasing temperature. This approximate degeneracy suggests emergent\n$SU(2)_{CS}$ and $SU(4)$ symmeries at high temperatures, that mix left- and\nright-handed quarks."
    },
    {
        "anchor": "Non-perturbatively renormalised light quark masses from a lattice\n  simulation with N_f=2: We present results for the light quark masses obtained from a lattice QCD\nsimulation with N_f=2 degenerate Wilson dynamical quark flavours. The sea quark\nmasses of our lattice, of spacing a ~ 0.06 fm, are relatively heavy, i.e., they\ncover the range corresponding to 0.60 <~ M_P/M_V <~ 0.75. After implementing\nthe non-perturbative RI-MOM method to renormalise quark masses, we obtain\nm_{ud}^{MS}(2 GeV)=4.3 +- 0.4^{+1.1}_{-0} MeV, and m_s^{MS}(2 GeV)=101 +-\n8^{+25}_{-0} MeV, which are about 15% larger than they would be if renormalised\nperturbatively. In addition, we show that the above results are compatible with\nthose obtained in a quenched simulation with a similar lattice.",
        "positive": "Rationale for UV-filtered clover fermions: We study the contributions Sigma_0 and Sigma_1, proportional to a^0 and a^1,\nto the fermion self-energy in Wilson's formulation of lattice QCD with\nUV-filtering in the fermion action. We derive results for m_{crit} and the\nrenormalization factors Z_S, Z_P, Z_V, Z_A to 1-loop order in perturbation\ntheory for several filtering recipes (APE, HYP, EXP, HEX), both with and\nwithout a clover term. The perturbative series is much better behaved with\nfiltering, in particular tadpole resummation proves irrelevant. Our\nnon-perturbative data for m_{crit} and Z_A/(Z_m*Z_P) show that the combination\nof filtering and clover improvement efficiently reduces the amount of chiral\nsymmetry breaking -- we find residual masses am_{res}=O(10^{-2})."
    },
    {
        "anchor": "The pion and proton mass in finite volume: We calculate the finite volume effects for the pion and nucleon mass. For the\npion mass we present the results of a full two-loop calculation in chiral\nperturbation theory. The outcome shows that the resummed version of the Luscher\nformula we presented in an earlier work does indeed give an excellent\napproximation to the two-loop result. In view of this result we apply the same\nresummed formula to the nucleon mass. In the nucleon sector the extension of\nthe chiral expansion to higher quark masses appears to be more problematic and\nit is therefore more difficult to make reliable predictions for the size of the\nfinite volume effects. We present some preliminary numerical estimates.",
        "positive": "The $I=1$ pion-pion scattering amplitude and timelike pion form factor\n  from $N_{\\rm f} = 2+1$ lattice QCD: The elastic $I=1$ $p$-wave $\\pi\\pi$ scattering amplitude is calculated\ntogether with the isovector timelike pion form factor using lattice QCD with\n$N_{\\rm f}=2+1$ dynamical quark flavors. Wilson clover ensembles generated by\nthe Coordinated Lattice Simulations (CLS) initiative are employed at four\nlattice spacings down to $a = 0.05\\,\\mathrm{fm}$, several pion masses down to\n$m_{\\pi} = 200\\,\\mathrm{MeV}$, and spatial volumes of extent $L =\n3.1-5.5\\,\\mathrm{fm}$. The set of measurements on these ensembles, which is\npublicly available, enables an investigation of systematic errors due to the\nfinite lattice spacing and spatial volume. The $\\pi\\pi$ scattering amplitude is\nfit on each ensemble by a Breit-Wigner resonance lineshape, while the form\nfactor is described better by a thrice-subtracted dispersion relation than the\nGounaris-Sakurai parametrization."
    },
    {
        "anchor": "Dilaton chiral perturbation theory at next-to-leading order: We apply dilaton chiral perturbation theory (dChPT) at next-to-leading order\nto lattice data from the LatKMI collaboration for the eight-flavor SU(3) gauge\ntheory. In previous work, we found that leading-order dChPT does not account\nfor these data, but that a model extension of leading-order dChPT with a\nvarying mass anomalous dimension describes these data well. Here we calculate\nthe next-to-leading order corrections for the pion mass and decay constant. We\nfocus on these quantities, as data for the dilaton mass are of poorer quality.\nThe application of next-to-leading order dChPT is difficult because of the\nlarge number of new low-energy constants, and the results of our fits turn out\nto be inconclusive. They suggest -- yet cannot firmly establish -- that the\nLatKMI mass range might be outside the scope of dChPT.",
        "positive": "Polyakov Loop Susceptibility and Correlators in the Chiral Limit: In quenched QCD the Polyakov loop is an order parameter of the deconfinement\ntransition, but with decreasing quark mass, the peak in the Polyakov loop\nsusceptibility becomes less pronounced, and it loses its interpretation as an\nindicator for deconfinement. For this $N_f=2+1$ HISQ study, we fix the strange\nquark mass $m_s$ at its physical value and investigate the dependence of the\nPolyakov loop on the light quark mass $m_l$ in the range $m_s/m_l=27-160$,\nfollowing $m_l$ toward the chiral limit. In particular we will look how the\ninflection point and susceptibility behave as we decrease $m_l$, to see whether\none finds any indication of a crossover, and therefore whether the Polyakov\nloop is sensitive to the chiral phase transition. Preliminary results show no\nsignal of a crossover from the real part of the Polyakov loop in the vicinity\nof the chiral crossover. Closely related is an investigation of Polyakov loop\ncorrelations and the Debye mass in this limit. Preliminary results suggest\nlittle or no dependence on $m_l$."
    },
    {
        "anchor": "The QCD Sign Problem for Small Chemical Potential: The expectation value of the complex phase factor of the fermion determinant\nis computed in the microscopic domain of QCD at nonzero chemical potential. We\nfind that the average phase factor is non-vanishing below a critical value of\nthe chemical potential equal to the half the pion mass and vanishes\nexponentially in the volume for larger values of the chemical potential. This\nholds for QCD with dynamical quarks as well as for quenched and phase quenched\nQCD. The average phase factor has an essential singularity for zero chemical\npotential and cannot be obtained by analytic continuation from imaginary\nchemical potential or by means of a Taylor expansion. The leading order\ncorrection in the $p$-expansion of the chiral Lagrangian is calculated as well.",
        "positive": "BRST symmetry vs. Horizon condition in Yang-Mills theories: We show that in SU(2) Yang-Mills theories a simple relation exists between\nlattice gluon propagators in Coulomb and Landau gauge and discuss the physical\nimplications of such result. In particular, the realization of the\nGribov-Zwanziger confinement mechanism in Coulomb gauge, linked to\ndual-superconductivity, would imply that the standard BRST charge must be ill\ndefined non perturbatively. As a consequence, the Kugo-Ojima confinement\ncriterion, which relies on BRST charge conservation beyond perturbation theory,\nwould not be fulfilled."
    },
    {
        "anchor": "Compact U(1) Gauge Theory on Lattices with Trivial Homotopy Group: We study the pure gauge model on a lattice manifold with trivial fundamental\nhomotopy group, homotopically equivalent to an $S_4$. Monopole loops may\nfluctuate freely on that lattice without restrictions due to the boundary\nconditions. For the original Wilson action on the hypertorus there is an\nestablished two-state signal in energy distribution functions which disappears\nfor the new geometry. Our finite size scaling analysis suggests stringent upper\nbounds on possible discontinuities in the plaquette action. However, no\nconsistent asymptotic finite size scaling behaviour is observed.",
        "positive": "Perturbative analysis for Kaplan's lattice chiral fermions: Perturbation theory for lattice fermions with domain wall mass terms is\ndeveloped and is applied to investigate the chiral Schwinger model formulated\non the lattice by Kaplan's method. We calculate the effective action for gauge\nfields to one loop, and find that it contains a longitudinal component even for\nanomaly-free cases. From the effective action we obtain gauge anomalies and\nChern-Simons current without ambiguity. We also show that the current\ncorresponding to the fermion number has a non-zero divergence and it flows off\nthe wall into the extra dimension. Similar results are obtained for a proposal\nby Shamir, who used a constant mass term with free boundaries instead of domain\nwalls."
    },
    {
        "anchor": "Revisiting the flux tube spectrum of 3d SU(2) lattice gauge theory: We perform a high precision measurement of the spectrum of the QCD flux tube\nin three-dimensional $\\SU(2)$ gauge theory at multiple lattice spacings. We\ncompare the results at large $q\\bar{q}$ separations $R$ to the spectrum\npredicted by the effective string theory, including the leading order boundary\nterm with a non-universal coefficient. We find qualitative agreement with the\npredictions from the leading order Nambu-Goto string theory down to small\nvalues of $R$, while, at the same time, observing the predicted splitting of\nthe second excited state due to the boundary term. On fine lattices and at\nlarge $R$ we observe slight deviations from the EST predictions for the first\nexcited state.",
        "positive": "Possible Failure of Asymptotic Freedom in Two-Dimensional $RP^2$ and\n  $RP^3$ $\u03c3$-Models: We have simulated the two-dimensional $RP^2$ and $RP^3$ $\\sigma$-models, at\ncorrelation lengths up to about 220 (resp.\\ 30), using a Wolff-type embedding\nalgorithm. We see no evidence of asymptotic scaling. Indeed, the data rule out\nthe conventional asymptotic scaling scenario at all correlation lengths less\nthan about $10^{9}$ (resp.\\ $10^{5}$). Moreover, they are consistent with a\ncritical point at $\\beta \\approx 5.70$ (resp.\\ 6.96), only 2\\% (resp.\\ 5\\%)\nbeyond the largest $\\beta$ at which we ran. Preliminary studies of a mixed\n$S^{N-1}/RP^{N-1}$ model (i.e. isovector + isotensor action) show a similar\nbehavior when $\\beta_T \\to \\infty$ with $\\beta_V$ fixed $\\ltapprox 0.6$, while\nthey are consistent with conventional asymptotic freedom along the lines\n$\\beta_T/\\beta_V$ fixed $\\ltapprox 2$. Taken as a whole, the data cast doubt on\n(though they do not completely exclude) the idea that $RP^{N-1}$ and $S^{N-1}$\n$\\sigma$-models lie in the same universality class."
    },
    {
        "anchor": "Dense baryonic matter in strong coupling lattice gauge theory: We investigate the strong coupling limit of lattice QCD in the Hamiltonian\nformulation for systems with non-zero baryon density. In leading order the\nHamiltonian looks like an antiferromagnet that is invariant under global\nU(N_f)xU(N_f) and local SU(N_c). Physically it describes meson dynamics with a\nfixed background of baryon density. We study this Hamiltonian with several\nbaryon number distributions, and concentrate on the global symmetries of the\nground state and on the properties of low lying excitations. In particular, for\nuniform non-zero baryon density we write the partition function as a path\nintegral that is tractable in the limit of large N_c. We find that the ground\nstate spontaneously breaks chiral symmetry as well as discrete lattice\nrotations in a way that depends on N_f and the density. The low energy\nexcitations include type I and type II Goldstone bosons. The energies of the\nlatter are of order 1/N_c, and are quadratic in momentum. Bosons of either type\ncan develop anisotropic dispersion relations.",
        "positive": "Anomalous finite-size scaling at thermal first-order transitions in\n  systems with disordered boundary conditions: We investigate the equilibrium and off-equilibrium behaviors of systems at\nthermal first-order transitions (FOTs) when the boundary conditions favor one\nof the two phases. As a theoretical laboratory we consider the two-dimensional\nPotts model. We show that an anomalous finite-size scaling emerges in systems\nwith open boundary conditions favoring the disordered phase, associated with a\nmixed regime where the two phases are spatially separated. Correspondingly, if\nthe system is slowly heated across the transition, the characteristic times of\nthe off-equilibrium dynamics scale with a power of the size. We argue that\nthese features generally apply to systems at FOTs, when boundary conditions\nfavor one of the two phases. In particular, they should be relevant for the\nexperimental search of FOTs of the quark-gluon plasma in heavy-ion collisions."
    },
    {
        "anchor": "The $B \\to D \\ell \u03bd$ form factors at nonzero recoil and $|V_{cb}|$\n  from $2+1$-flavor lattice QCD: We present the first unquenched lattice-QCD calculation of the hadronic form\nfactors for the exclusive decay $\\overline{B} \\rightarrow D \\ell\n\\overline{\\nu}$ at nonzero recoil. We carry out numerical simulations on\nfourteen ensembles of gauge-field configurations generated with 2+1 flavors of\nasqtad-improved staggered sea quarks. The ensembles encompass a wide range of\nlattice spacings (approximately 0.045 to 0.12 fm) and ratios of light (up and\ndown) to strange sea-quark masses ranging from 0.05 to 0.4. For the $b$ and $c$\nvalence quarks we use improved Wilson fermions with the Fermilab\ninterpretation, while for the light valence quarks we use asqtad-improved\nstaggered fermions. We extrapolate our results to the physical point using\nrooted staggered heavy-light meson chiral perturbation theory. We then\nparameterize the form factors and extend them to the full kinematic range using\nmodel-independent functions based on analyticity and unitarity. We present our\nfinal results for $f_+(q^2)$ and $f_0(q^2)$, including statistical and\nsystematic errors, as coefficients of a series in the variable $z$ and the\ncovariance matrix between these coefficients. We then fit the lattice\nform-factor data jointly with the experimentally measured differential decay\nrate from BaBar to determine the CKM matrix element, $|V_{cb}|=(39.6 \\pm\n1.7_{\\rm QCD+exp} \\pm 0.2_{\\rm QED})\\times 10^{-3}$. As a byproduct of the\njoint fit we obtain the form factors with improved precision at large recoil.\nFinally, we use them to update our calculation of the ratio $R(D)$ in the\nStandard Model, which yields $R(D) = 0.299(11)$.",
        "positive": "Density Matrix Renormalisation Group Approach to the Massive Schwinger\n  Model: The massive Schwinger model is studied, using a density matrix\nrenormalisation group approach to the staggered lattice Hamiltonian version of\nthe model. Lattice sizes up to 256 sites are calculated, and the estimates in\nthe continuum limit are almost two orders of magnitude more accurate than\nprevious calculations. Coleman's picture of `half-asymptotic' particles at\nbackground field theta = pi is confirmed. The predicted phase transition at\nfinite fermion mass (m/g) is accurately located, and demonstrated to belong in\nthe 2D Ising universality class."
    },
    {
        "anchor": "Two-Loop Computation of the Schroedinger Functional in Pure SU(3)\n  Lattice Gauge Theory: We compute the Schroedinger functional (SF) for the case of pure SU(3) gauge\ntheory at two-loop order in lattice perturbation theory. This allows us to\nextract the three-loop beta-function in the SF-scheme. These results are\nrequired to compute the running coupling, the Lambda-parameter and quark masses\nby finite size techniques with negligible systematic errors. In addition, we\ncan now implement two-loop O(a) improvement in simulations and extend and study\nseries in alternative (\"tadpole-improved\") bare couplings.",
        "positive": "Hybrid Monte Carlo with Fat Link Fermion Actions: The use of APE smearing or other blocking techniques in lattice fermion\nactions can provide many advantages. There are many variants of these fat link\nactions in lattice QCD currently, such as FLIC fermions. The FLIC fermion\nformalism makes use of the APE blocking technique in combination with a\nprojection of the blocked links back into the special unitary group. This\nreunitarisation is often performed using an iterative maximisation of a gauge\ninvariant measure. This technique is not differentiable with respect to the\ngauge field and thus prevents the use of standard Hybrid Monte Carlo simulation\nalgorithms. The use of an alternative projection technique circumvents this\ndifficulty and allows the simulation of dynamical fat link fermions with\nstandard HMC and its variants. The necessary equations of motion for FLIC\nfermions are derived, and some initial simulation results are presented. The\ntechnique is more general however, and is straightforwardly applicable to other\nsmearing techniques or fat link actions."
    },
    {
        "anchor": "Strangeness in the nucleon from a mixed action calculation: The contributions of strange quarks to the nucleon mass and the nucleon spin\nare investigated in a mixed action scheme employing domain wall valence quarks\nand quark loops on MILC asqtad dynamical fermion ensembles. Results are\npresented for pion masses 495 MeV and 356 MeV.",
        "positive": "Effects of Dynamical Quarks in UKQCD Simulations: Recent results from the UKQCD Collaboration's dynamical simulations are\npresented. The main feature of these ensembles is that they have a fixed\nlattice spacing and volume, but varying sea quark mass from infinite\n(corresponding to the quenched simulation) down to roughly that of the strange\nquark mass. The main aim of this work is to uncover dynamical quark effects\nfrom these ``matched'' ensembles. We obtain some evidence of dynamical quark\neffects in the static quark potential with less effects in the hadronic\nspectrum."
    },
    {
        "anchor": "A note on the solutions of the Ginsparg-Wilson relation: The role of R in the solutions of the Ginsparg-Wilson relation is discussed.",
        "positive": "Chiral condensate in the quenched Schwinger model: A numerical investigation of the quenched Schwinger model on the lattice\nusing the overlap Dirac operator points to a divergent chiral condensate."
    },
    {
        "anchor": "Exact Chiral Symmetry with a non-perturbative cutoff: The main ideas behind the new ways to preserve chiral symmetries for lattice\nfermions are presented. The discussion is focused on vector-like fermions, the\ncase relevant for lattice QCD.",
        "positive": "Chiral symmetry restoration at large chemical potential in strongly\n  coupled SU(N) gauge theories: We show that at sufficiently large chemical potential SU(N) lattice gauge\ntheories in the strong coupling limit with staggered fermions are in a chirally\nsymmetric phase. The proof employs a polymer cluster expansion which exploits\nthe anisotropy between timelike and spacelike directions in the presence of a\nquark chemical potential $\\mu$. The expansion is shown to converge in the\ninfinite volume limit at any temperature for sufficiently large $\\mu$. All\nexpectations of chirally non-invariant local fermion operators vanish\nidentically, or, equivalently, their correlations cluster exponentially, within\nthe expansion. The expansion itself may serve as a computational tool at large\n$\\mu$ and strong coupling."
    },
    {
        "anchor": "Lee-Yang Zeroes and Logarithmic Corrections in the $\u03a6^4_4$ Theory: The leading mean-field critical behaviour of $\\phi^4_4$-theory is modified by\nmultiplicative logarithmic corrections. We analyse these corrections both\nanalytically and numerically. In particular we present a finite-size scaling\ntheory for the Lee-Yang zeroes and temperature zeroes, both of which exhibit\nlogarithmic corrections. On lattices from size $8^4$ to $24^4$, Monte-Carlo\ncluster methods and multi-histogram techniques are used to determine the\npartition function zeroes closest to the critical point. Finite-size scaling\nbehaviour is verified and the logarithmic corrections are found to be in good\nagreement with our analytical predictions.",
        "positive": "Perturbative renormalization of the first two moments of non-singlet\n  quark distributions with overlap fermions: Using the overlap-Dirac operator proposed by Neuberger, we have computed in\nlattice QCD the one-loop renormalization factors of ten operators which measure\nthe lowest two moments of unpolarized and polarized non-singlet quark\ndistributions. These factors are necessary to extract physical numbers from\nMonte Carlo simulations made with overlap fermions.\n  An exact chiral symmetry is maintained in all our results, and the\nrenormalization constants of corresponding unpolarized and polarized operators\nwhich differ by a $\\gamma_5$ matrix have the same value. We have considered two\nlattice representations for each continuum operator. The computations have been\ncarried out using the symbolic language FORM, in a general covariant gauge. In\nsome simple cases they have also been checked by hand."
    },
    {
        "anchor": "Fitting Correlated Hadron Mass Spectrum Data: We discuss fitting hadronic Green functions versus time $t$ to extract mass\nvalues in quenched lattice QCD. These data are themselves strongly correlated\nin $t$. With only a limited number of data samples, the method of minimising\ncorrelated $\\chi^2$ is unreliable. We explore several methods of modelling the\ncorrelations among the data set by a few parameters which then give a stable\nand sensible fit even if the data sample is small. In particular these models\ngive a reliable estimate of the goodness of fit.",
        "positive": "Extending the eigCG algorithm to non-symmetric linear systems with\n  multiple right-hand sides: For Hermitian positive definite linear systems and eigenvalue problems, the\neigCG algorithm is a memory efficient algorithm that solves the linear system\nand simultaneously computes some of its eigenvalues. The algorithm is based on\nthe Conjugate-Gradient (CG) algorithm, however, it uses only a window of the\nvectors generated by the CG algorithm to compute approximate eigenvalues. The\nnumber and accuracy of the eigenvectors can be increased by solving more\nright-hand sides. For Hermitian systems with multiple right-hand sides, the\ncomputed eigenvectors can be used to speed up the solution of subsequent\nsystems. The algorithm was tested on Lattice QCD problems by solving the normal\nequations and was shown to give large speed up factors and to remove the\ncritical slowing down as we approach light quark masses. Here, an extension to\nthe non-symmetric case based on the two-sided Lanczos algorithm is given. The\nnew algorithm is tested on Lattice QCD problems and is shown to give promising\nresults. We also study the removal of the critical slowing down and compare\nresults with those of the eigCG algorithm. We also discuss the case when the\nsystem is gamma5-Hermitian."
    },
    {
        "anchor": "Improving the Volume Dependence of Two-Body Binding Energies Calculated\n  with Lattice QCD: Volume modifications to the binding of two-body systems in large cubic\nvolumes of extent L depend upon the total momentum and exponentially upon the\nratio of L to the size of the boosted system. Recent work by Bour et al\ndetermined the momentum dependence of the leading volume modifications to\nnonrelativistic systems with periodic boundary conditions imposed on the\nsingle-particle wavefunctions, enabling them to numerically determine the\nscattering of such bound states using a low-energy effective field theory and\nLuscher's finite-volume method. The calculation of bound nuclear systems\ndirectly from QCD using Lattice QCD has begun, and it is important to reduce\nthe systematic uncertainty introduced into such calculations by the finite\nspatial extent of the gauge-field configurations. We extend the work of Bour et\nal from nonrelativistic quantum mechanics to quantum field theory by\ngeneralizing the work of Luscher and of Gottlieb and Rummukainen to boosted\ntwo-body bound states. The volume modifications to binding energies can be\nexponentially reduced from ~ e^{-kappa L}/L to ~ e^{-2 kappa L}/L in\nnonrelativistic systems (where kappa is the binding momentum of the state) by\nforming particular combinations of the binding energies determined in the four\nlowest-lying boosted systems. Relativistic corrections to this combination, and\nothers, that violate the exponential reduction are determined. An analysis of\nwhat can be expected from Lattice QCD calculations of the deuteron is\nperformed, the results of which are representative of a generic loosely bound\nsystem.",
        "positive": "U(1) lattice gauge theory with a topological action: We investigate the phase diagram of the compact $U(1)$ lattice gauge theory\nin four dimensions using a non-standard action which is invariant under\ncontinuous deformations of the plaquette angles. Just as for the Wilson action,\nwe find a weakly first order transition, separating a confining phase where\nmagnetic monopoles condense, and a Coulomb phase where monopoles are dilute. We\nalso find a third phase where monopoles are completely absent. The topological\naction offers an algorithmic advantage for the computation of the free energy."
    },
    {
        "anchor": "Higgs compositeness in $\\mathrm{Sp}(2N)$ gauge theories --- The pure\n  gauge model: As a first step in the study of $\\mathrm{Sp}(2N)$ composite Higgs models, we\nobtained a set of novel numerical results for the pure gauge $\\mathrm{Sp}(4)$\nlattice theory in 3+1 space-time dimensions. Results for the continuum\nextrapolations of the string tension and the glueball mass spectrum are\npresented and their values are compared with the same quantities in\nneighbouring $\\mathrm{SU}(N)$ models.",
        "positive": "The form factors for B -> pi l nu semileptonic decay from 2+1 flavors of\n  domain-wall fermions: We present a calculation of the B -> pi l nu form factors with domain-wall\nlight quarks and relativistic b-quarks on the lattice. We work with the 2+1\nflavor domain-wall fermion and Iwasaki gauge-field ensembles generated by the\nRBC and UKQCD Collaborations. The chiral-continuum extrapolation is performed\nusing SU(2) hard-pion chiral perturbation theory. To extrapolate the lattice\nform factors to the full kinematic range, we use the model independent\nz-parameterization and impose the kinematic constraint f_+(0) = f_0(0) at zero\nmomentum transfer."
    },
    {
        "anchor": "Adaptive Multigrid Algorithm for the QCD Dirac-Wilson Operator: We present a new multigrid solver that is suitable for the Dirac operator in\nthe presence of disordered gauge fields. The key behind the success of the\nalgorithm is an adaptive projection onto the coarse grids that preserves the\nnear null space. The resulting algorithm has weak dependence on the gauge\ncoupling and exhibits mild critical slowing down in the chiral limit. Results\nare presented for the Wilson Dirac operator of the 2d U(1) Schwinger model.",
        "positive": "Simulations of Discrete Random Geometries: Simplicial Quantum Gravity\n  and Quantum String Theory: I investigate two discrete models of random geometries, namely simplicial\nquantum gravity and quantum string theory. In four-dimensional simplicial\nquantum gravity, I show that the addition of matter gauge fields to the model\nis capable of changing its phase structure by replacing the branched polymers\nof the pure gravity model with a new phase that has a negative string\nsusceptibility exponent and a fractal dimension of four. Some of the results\nare derived from a strong coupling expansion of the model, a technique which is\nused here for the first time in this context. In quantum string theory, I study\na discrete version of the IIB superstring. I show that the divergences\nencountered in the discretization of the bosonic string are eliminated in the\nsupersymmetric case. I give theoretical arguments for the appearance of\none-dimensional structures in the region of large system extents that manifest\nas a power-law tail in the link length distribution; this is confirmed by\nnumerical simulations of the model. I also examine a lower-dimensional version\nof the IKKT matrix model, in which a similar effect can be observed."
    },
    {
        "anchor": "Lattice QCD calculation of the two-photon exchange contribution to the\n  muonic-hydrogen Lamb shift: We develop a method for lattice QCD calculation of the two-photon exchange\n(TPE) contribution to the muonic-hydrogen Lamb shift. To demonstrate the\nfeasibility of this method, we also present an exploratory study with a gauge\nensemble at $m_\\pi = 142$ MeV. By adopting the infinite-volume reconstruction\n(IVR) method along with an optimized subtraction scheme, we obtain a\npreliminary result of the TPE contribution which agrees well with previous\ncalculation using other methods and one magnitude smaller compare to the large\n$\\sim300~\\mu$eV discrepancy for the proton radius puzzle.",
        "positive": "B Physics on the Lattice: $\\overline\u039b$, $\u03bb_{1}$,\n  $\\overline{m}_{b}(\\overline{m}_{b})$, $\u03bb_2$, $B^{0}-\\bar{B}^{0}$\n  mixing, $\\fb$ and all that: We present a short review of our most recent high statistics lattice\ndeterminations in the HQET of the following important parameters in B physics:\nthe B--meson binding energy, $\\overline{\\Lambda}$ and the kinetic energy of the\nb quark in the B meson, $\\lambda_1$, which due to the presence of power\ndivergences require a non--perturbative renormalization to be defined; the\n$\\overline{MS}$ running mass of the b quark,\n$\\overline{m}_{b}(\\overline{m}_{b})$; the $B^{*}$--$B$ mass splitting, whose\nvalue in the HQET is determined by the matrix element of the chromo--magnetic\noperator between B meson states, $\\lambda_2$; the B parameter of the\n$B^{0}$--$\\bar{B}^{0}$ mixing, $B_{B}$, and the decay constant of the B meson,\n$f_{B}$. All these quantities have been computed using a sample of $600$ gauge\nfield configurations on a $24^{3}\\times 40$ lattice at $\\beta=6.0$. For\n$\\overline{\\Lambda}$ and $\\overline{m}_{b}(\\overline{m}_{b})$, we obtain our\nestimates by combining results from three independent lattice simulations at\n$\\beta=6.0$, $6.2$ and $6.4$ on the same volume."
    },
    {
        "anchor": "Listening to Noise: We show how sign problems in simulations of many-body systems can manifest\nthemselves in the form of heavy-tailed correlator distributions, similar to\nwhat is seen in electron propagation through disordered media. We propose an\nalternative statistical approach for extracting ground state energies in such\nsystems, illustrating the method with a toy model and with lattice data for\nunitary fermions and for baryons in QCD.",
        "positive": "Improved analysis of nucleon isovector charges and twist-2 matrix\n  elements on CLS $N_f=2+1$ ensembles: Preliminary results are presented for nucleon isovector charges and twist-2\nmatrix elements which have been obtained employing an improved analysis\nstrategy to deal with excited-state contamination. The set of CLS $N_f=2+1$\ngauge ensembles in this study has been extended compared to our 2018\ncalculation, including an ensemble at physical quark masses. Besides the\naddition of new ensembles, the number of gauge configurations and measurements\nhas been increased on several of the existing ensembles and the analysis has\nbeen extended to include additional source-sink separations. The ensembles\ncover a range of the light quark mass corresponding to $M_\\pi\\approx\n0.130\\,\\mathrm{MeV} \\ldots 350\\,\\mathrm{MeV}$, four values of the lattice\nspacing $a\\approx0.05\\,\\mathrm{fm}\\ldots0.09\\,\\mathrm{fm}$ and a large range of\nvolumes. Results at the physical point are computed for each observable from a\ncombined chiral, continuum and finite-volume extrapolation."
    },
    {
        "anchor": "Lattice fermions with complex mass: We present evidence in the Schwinger model that rooted staggered fermions may\ncorrectly describe the m<0 sector of a theory with an odd number of flavors. We\npoint out that in QCD-type theories with a complex-valued quark mass every\nnon-chiral action essentially \"borrows\" knowledge about the\ntheta-transformation properties from the overlap action.",
        "positive": "Comparison of the gradient flow with cooling in $SU(3)$ pure gauge\n  theory: The gradient (Wilson) flow has been introduced recently in order to provide a\nsolid theoretical framework for the smoothing of ultraviolet noise in lattice\ngauge configurations. It is interesting to ask how it compares with other, more\nheuristic and numerically cheaper smoothing techniques, such as standard\ncooling. In this study we perform such a comparison, focusing on observables\nrelated to topology. We show that, already for moderately small lattice\nspacings, standard cooling and the gradient flow lead to equivalent results,\nboth for average quantities and configuration by configuration."
    },
    {
        "anchor": "Update on onium masses with three flavors of dynamical quarks: We update results presented at Lattice 2005 on charmonium masses. New\nensembles of gauge configurations with 2+1 flavors of improved staggered quarks\nhave been analyzed. Statistics have been increased for other ensembles. New\nresults are also available for P-wave mesons and for bottomonium on selected\nensembles.",
        "positive": "Lattice SU(2) on GPU's: We discuss the CUDA approach to the simulation of pure gauge Lattice SU(2).\nCUDA is a hardware and software architecture developed by NVIDIA for computing\non the GPU. We present an analysis and performance comparison between the GPU\nand CPU with single precision. Analysis with single and multiple GPU's, using\nCUDA and OPENMP, are also presented. In order to obtain a high performance, the\ncode must be optimized for the GPU architecture, i.e., an implementation that\nexploits the memory hierarchy of the CUDA programming model. Using GPU texture\nmemory and minimizing the data transfers between CPU and GPU, we achieve a\nspeedup of $200\\times$ using 2 NVIDIA 295 GTX cards relative to a serial CPU,\nwhich demonstrates that GPU's can serve as an efficient platform for scientific\ncomputing. With multi-GPU's we are able, in one day computation, to generate 1\n000 000 gauge configurations in a $48^4$ lattice with $\\beta=6.0$ and calculate\nthe mean average plaquette. We present results for the mean average plaquette\nin several lattice sizes for different $\\beta$. Finally we present results for\nthe mean average Polyakov loop at finite temperature."
    },
    {
        "anchor": "Charge transport and vector meson dissociation across the thermal phase\n  transition in lattice QCD with two light quark flavors: We compute and analyze correlation functions in the isovector vector channel\nat vanishing spatial momentum across the deconfinement phase transition in\nlattice QCD. The simulations are carried out at temperatures $T/T_c=0.156, 0.8,\n1.0, 1.25$ and $1.67$ with $T_c\\simeq203$MeV for two flavors of Wilson-Clover\nfermions with a zero-temperature pion mass of $\\simeq270$MeV. Exploiting exact\nsum rules and applying a phenomenologically motivated ansatz allows us to\ndetermine the spectral function $\\rho(\\omega,T)$ via a fit to the lattice\ncorrelation function data. From these results we estimate the electrical\nconductivity across the deconfinement phase transition via a Kubo formula and\nfind evidence for the dissociation of the $\\rho$ meson by resolving its\nspectral weight at the available temperatures. We also apply the Backus-Gilbert\nmethod as a model-independent approach to this problem. At any given frequency,\nit yields a local weighted average of the true spectral function. We use this\nmethod to compare kinetic theory predictions and previously published\nphenomenological spectral functions to our lattice study.",
        "positive": "The renormalised $\\mathrm{O}(a)$ improved vector current in\n  three-flavour lattice QCD with Wilson quarks: We present the results of a non-perturbative determination of the improvement\ncoefficient $c_\\mathrm{V}$ and the renormalisation factor $Z_\\mathrm{V}$, which\ndefine the renormalised vector current in three-flavour $\\mathrm{O}(a)$\nimproved lattice QCD with Wilson quarks and tree-level Symanzik-improved gauge\naction. In case of the improvement coefficient, we consider both lattice\ndescriptions of the vector current, the local as well as the conserved (i.e.,\npoint-split) one. Our improvement and normalisation conditions are based on\nmassive chiral Ward identities and numerically evaluated in the Schr\\\"odinger\nfunctional setup, which allows to eliminate finite quark mass effects in a\ncontrolled way. In order to ensure a smooth dependence of the renormalisation\nconstant and improvement coefficients on the bare gauge coupling, our\ncomputation proceeds along a line of constant physics, covering the typical\nrange of lattice spacings $0.04\\,\\mathrm{fm}\\lesssim a\\lesssim\n0.1\\,\\mathrm{fm}$ that is useful for phenomenological applications. Especially\nfor the improvement coefficient of the local vector current, we report\nsignificant differences between the one-loop perturbative estimates and our\nnon-perturbative results."
    },
    {
        "anchor": "Progress on Meson-Baryon Scattering: Progress in computing various meson-baryon scattering amplitudes is presented\non a single ensemble from the Coordinated Lattice Simulations (CLS) consortium\nwith $m_\\pi=200$ MeV and $N_f=2+1$ dynamical fermions. The finite-volume\nL\\\"uscher approach is employed to determine the lowest few partial waves from\nground- and excited-state energies computed from correlation matrices rotated\nin a single pivot using a generalized eigenvector solution. This analysis\nrequires evaluating matrices of correlation functions between single- and\ntwo-hadron interpolating operators which are projected onto definite spatial\nmomenta and finite-volume irreducible representations. The stochastic LapH\nmethod is used to estimate all needed quark propagators. Preliminary results\nare presented for $I=\\frac{1}{2}, \\frac{3}{2}$ $N\\pi$ amplitudes including the\n$\\Delta(1232)$ resonance and the $I=0$ $S$-wave amplitude with unit strangeness\nrelevant for the $\\Lambda(1405)$.",
        "positive": "From asymptotic freedom to $\u03b8$ vacua: Qubit embeddings of the O(3)\n  nonlinear $\u03c3$ model: Conventional lattice formulations of $\\theta$ vacua in the $1+1$-dimensional\n$\\text{O}(3)$ nonlinear sigma model suffer from a sign problem. Here, we\nconstruct the first sign-problem-free regularization for arbitrary $\\theta$.\nUsing efficient lattice Monte Carlo algorithms, we demonstrate how a\nHamiltonian model of spin-$\\tfrac12$ degrees of freedom on a 2-dimensional\nspatial lattice reproduces both the infrared sector for arbitrary $\\theta$, as\nwell as the ultraviolet physics of asymptotic freedom. Furthermore, as a model\nof qubits on a two-dimensional square lattice with only nearest-neighbor\ninteractions, it is naturally suited for studying the physics of $\\theta$ vacua\nand asymptotic freedom on near-term quantum devices. Our construction\ngeneralizes to $\\theta$ vacua in all $\\text{CP}(N-1)$ models, solving a long\nstanding sign problem."
    },
    {
        "anchor": "The $SU(\\infty)$ twisted gradient flow running coupling: We measure the running of the $SU(\\infty)$ 't Hooft coupling by performing a\nstep scaling analysis of the Twisted Eguchi-Kawai (TEK) model, the SU($N$)\ngauge theory on a single site lattice with twisted boundary conditions. The\ncomputation relies on the conjecture that finite volume effects for SU(N) gauge\ntheories defined on a 4-dimensional twisted torus are controlled by an\neffective size parameter $\\tilde l = l \\sqrt{N}$, with $l$ the torus period. We\nset the scale for the running coupling in terms of $\\tilde l$ and use the\ngradient flow to define a renormalized 't Hooft coupling $\\lambda(\\tilde l)$.\nIn the TEK model, this idea allows the determination of the running of the\ncoupling through a step scaling procedure that uses the rank of the group as a\nsize parameter. The continuum renormalized coupling constant is extracted in\nthe zero lattice spacing limit, which in the TEK model corresponds to the large\n$N$ limit taken at fixed value of $\\lambda(\\tilde l)$. The coupling constant is\nthus expected to coincide with that of the ordinary pure gauge theory at $N\n=\\infty$. The idea is shown to work and permits us to follow the evolution of\nthe coupling over a wide range of scales. At weak coupling we find a remarkable\nagreement with the perturbative two-loop formula for the running coupling.",
        "positive": "Pion Valence Structure from Ioffe Time Pseudo-Distributions: We present a calculation of the pion valence quark distribution extracted\nusing the formalism of reduced Ioffe time pseudo-distributions or more commonly\nknown as pseudo-PDFs. Our calculation is carried out on two different 2+1\nflavor QCD ensembles using the isotropic-clover fermion action, with lattice\ndimensions $24^3\\times 64$ and $32^3\\times 96$ at the lattice spacing of\n$a=0.127$ fm, and with the quark mass equivalent to a pion mass of $m_\\pi\n\\simeq 415$ MeV. We incorporate several combinations of smeared-point and\nsmeared-smeared pion source-sink interpolation fields in obtaining the lattice\nQCD matrix elements using the summation method. After one-loop perturbative\nmatching and combining the pseudo-distributions from these two ensembles, we\nextract the pion valence quark distribution using a phenomenological functional\nform motivated by the global fits of parton distribution functions. We also\ncalculate the lowest four moments of the pion quark distribution through the\n\"OPE without OPE\". We present a qualitative comparison between our lattice QCD\nextraction of the pion valence quark distribution with that obtained from\nglobal fits and previous lattice QCD calculations."
    },
    {
        "anchor": "Meson correlators above deconfinement: We review recent progress in studying spectral functions for mesonic\nobservables at finite temperatures, by analysis of imaginary time correlators\ndirectly calculated on isotropic lattices. Special attention is paid to the\nlattice artifacts present in such calculations.",
        "positive": "Analysis of the Schroedinger Functional with Chirally Rotated Boundary\n  Conditions: The Schroedinger functional provides a valuable tool to perform\nnon-perturbative renormalization on the lattice, in particular in a mass\nindependent scheme. We study two different types of chirally rotated\nSchroedinger functional boundary conditions which have been recently proposed\nto retain the bulk automatic O(a) improvement of massless Wilson fermions in\nfinite volume. We investigate the spectral properties and the quark propagators\nwhich derive from these two proposals in the continuum at tree-level of\nperturbation theory."
    },
    {
        "anchor": "Recent Results on the Abelian Projection of Lattice Gluodynamics: The abelian projection of lattice gluodynamics is reviewed. The main topics\nare: abelian and monopole dominance, monopole condensate as the disorder\nparameter, effective abelian Lagrangian, monopoles in the instanton field,\nAharonov -- Bohm effect on the lattice.",
        "positive": "On Witten's global anomaly for higher SU(2) representations: The spectral flow of the overlap operator is computed numerically along a\nparticular path in gauge field space. The path connects two gauge equivalent\nconfigurations which differ by a gauge transformation in the non-trivial class\nof pi_4(SU(2)). The computation is done with the SU(2) gauge field in the\nfundamental, the 3/2, and the 5/2 representation. The number of eigenvalue\npairs that change places along this path is established for these three\nrepresentations and an even-odd pattern predicted by Witten is verified."
    },
    {
        "anchor": "Study of the phase diagram of dense two-color QCD within lattice\n  simulation: In this paper we carry out a low-temperature scan of the phase diagram of\ndense two-color QCD with $N_f=2$ quarks. The study is conducted using lattice\nsimulation with rooted staggered quarks. At small chemical potential we observe\nthe hadronic phase, where the theory is in a confining state, chiral symmetry\nis broken, the baryon density is zero and there is no diquark condensate. At\nthe critical point $\\mu = m_{\\pi}/2$ we observe the expected second order\ntransition to Bose-Einstein condensation of scalar diquarks. In this phase the\nsystem is still in confinement in conjunction with non-zero baryon density, but\nthe chiral symmetry is restored in the chiral limit. We have also found that in\nthe first two phases the system is well described by chiral perturbation\ntheory. For larger values of the chemical potential the system turns into\nanother phase, where the relevant degrees of freedom are fermions residing\ninside the Fermi sphere, and the diquark condensation takes place on the Fermi\nsurface. In this phase the system is still in confinement, chiral symmetry is\nrestored and the system is very similar to the quarkyonic state predicted by\nSU($N_c$) theory at large $N_c$.",
        "positive": "The transversity parton distribution function of the nucleon using the\n  pseudo-distribution approach: We present a determination of the non-singlet transversity parton\ndistribution function (PDF) of the nucleon, normalized with respect to the\ntensor charge at $\\mu^2=2$ GeV$^2$ from lattice quantum chromodynamics. We\napply the pseudo-distribution approach, using a gauge ensemble with a lattice\nspacing of 0.094 fm and the light quark mass tuned to a pion mass of 358 MeV.\nWe extract the transversity PDF from the analysis of the short-distance\nbehavior of the Ioffe-time pseudo-distribution using the leading-twist\nnext-to-leading order (NLO) matching coefficients calculated for transversity.\nWe reconstruct the $x$-dependence of the transversity PDF through an expansion\nin a basis of Jacobi polynomials in order to reduce the PDF ansatz dependence.\nWithin the limitations imposed by a heavier-than-physical pion mass and a fixed\nlattice spacing, we present a comparison of our estimate for the valence\ntransversity PDF with the recent global fit results based on single transverse\nspin asymmetry. We find the intrinsic nucleon sea to be isospin symmetric with\nrespect to transversity."
    },
    {
        "anchor": "Computational Methods in Quantum Field Theory: After a brief introduction to the statistical description of data, these\nlecture notes focus on quantum field theories as they emerge from lattice\nmodels in the critical limit. For the simulation of these lattice models,\nMarkov chain Monte-Carlo methods are widely used. We discuss the heat bath and,\nmore modern, cluster algorithms. The Ising model is used as a concrete\nillustration of important concepts such as correspondence between a theory of\nbranes and quantum field theory or the duality map between strong and weak\ncouplings. The notes then discuss the inclusion of gauge symmetries in lattice\nmodels and, in particular, the continuum limit in which quantum Yang-Mills\ntheories arise.",
        "positive": "Heavy Quarks on the Lattice: I review the basic ideas behind lattice QCD calculations that involve charm\nand bottom quarks. I report on the progress in getting the correct hyperfine\nsplitting in charmonium from lattice QCD. Some of the basic technology behind\nnumerical lattice QCD calculations is explained by studying some specific\nexamples: computation of the charm quark mass, and the calculation of fB."
    },
    {
        "anchor": "Monte Carlo Calculation of the Surface Free Energy for the 2d 7-state\n  Potts Model, and an Estimate for 4d SU(3) Gauge Theory: Using the recently proposed multicanonical ensemble, we perform Monte Carlo\nsimulation for the 2d 7-state Potts model and calculate its surface free energy\ndensity (surface tension) to be $2 f^s = 0.0241 \\pm 0.0010$. This is an order\nof magnitude smaller than other estimates in the recent literature. Relying on\nexisting Monte Carlo data, we also give a preliminary estimate for the surface\ntension of 4d SU(3) lattice gauge theory with $L_t=2$.",
        "positive": "Approximation of the determinant of large sparse symmetric positive\n  definite matrices: This paper is concerned with the problem of approximating the determinant of\nA for a large sparse symmetric positive definite matrix A. It is shown that an\nefficient solution of this problem is obtained by using a sparse approximate\ninverse of A. The method is explained and theoretical properties are discussed.\nA posteriori error estimation techniques are presented. Furthermore, results of\nnumerical experiments are given which illustrate the performance of this new\nmethod."
    },
    {
        "anchor": "Decomposition of the static potential in the Maximal Abelian gauge: Decomposition of SU(2) gauge field into the monopole and monopoleless\ncomponents is studied in the Maximal Abelian gauge using Monte-Carlo\nsimulations in lattice SU(2) gluodynamics as well as in two-color QCD with both\nzero and nonzero quark chemical potential. The interaction potential between\nstatic charges is calculated for each component and their sum is compared with\nthe non-Abelian static potential. A good agreement is found in the confinement\nphase. Implications of this result are discussed.",
        "positive": "Evidence for X(3872) from DD* scattering on the lattice: A candidate for the charmonium(like) state X(3872) is found 11 +/- 7 MeV\nbelow the DD* threshold using dynamical Nf=2 lattice simulation with J^PC=1^++\nand I=0. This is the first lattice simulation that establishes a candidate for\nX(3872) in addition to the nearby scattering states D D* and J/psi omega, which\ninevitably have to be present in dynamical QCD. We extract large and negative\nDD* scattering length a_0=-1.7 +/- 0.4 fm and the effective range r_0=0.5 +/-\n0.1 fm, but their reliable determination will have to wait for a simulation on\na larger volume. In I=1 channel, only the D D* and J/psi rho scattering states\nare found and no candidate for X(3872). This is in agreement with the\ninterpretation that X(3872) is dominantly I=0, while its small I=1 component\narises solely from the isospin breaking and is therefore absent in our\nsimulation with m_u=m_d."
    },
    {
        "anchor": "New methods to measure phase transition strength: A recently developed technique to determine the order and strength of phase\ntransitions by extracting the density of partition function zeroes (a\ncontinuous function) from finite-size systems (a discrete data set) is\ngeneralized to systems for which (i) some or all of the zeroes occur in\ndegenerate sets and/or (ii) they are not confined to a singular line in the\ncomplex plane. The technique is demonstrated by application to the case of free\nWilson fermions.",
        "positive": "Chiral symmetry restoration in the three-dimensional four-fermion model\n  at non-zero temperature and density: The three-dimensional four-fermion model with a Z_2 chiral symmetry and N=4\nfermion species in the system is investigated numerically at non-zero\ntemparature and chemical potential. The phase diagram in the (chemical\npotential, temperature) plane is mapped out quantitatively. A detailed finite\nsize scaling analysis shows that the zero temperature and non-zero chemical\npotential chiral phase transition is first order, whereas the non-zero\ntemperature and non-zero chemical potential transition remains second order\ndown to very low temperatures. Quantitative results for the location of the end\nof the first order line are given. The simulations at T=0 provided no evidence\nfor a nuclear liquid-gas transition."
    },
    {
        "anchor": "Finite temperature effective string corrections in (3+1)D SU(2) lattice\n  gauge theory: We study the effective string corrections to the inter-quark potential at\nfinite temperature by simulating the SU(2) lattice gauge theory in four\ndimensions. We provide the first numerical evidence that the logarithmic\ncorrection to the potential, which was recently proposed to be a signature of\nthe effective string at finite temperature, is universal also in (3+1)D gauge\ntheory, thus extending previous results limited to the (2+1)D case.",
        "positive": "Computation of correlation matrices for tetraquark candidates with $J^P\n  = 0^+$ and flavor structure $q_1 \\bar{q_2} q_3 \\bar{q}_3$: The conjecture that several recently observed mesons have a structure, which\nis not dominated by an ordinary quark-antiquark pair, but by a four-quark\nstructure, is being actively investigated both theoretical and experimentally.\nSuch a state may be characterized as a mesonic molecule or as a\ndiquark-antidiquark pair. Lattice QCD provides a theoretically sound framework\nto study such states. To quantitatively investigate the internal structure of\nsuch mesons, one needs to precisely compute correlation matrices containing\nseveral interpolating operators including two and four quarks. Here we discuss\ncertain technical aspects of such correlation matrices suited to study\ntetraquark candidates with $J^P = 0^+$ and flavor structure $q_1 \\bar{q_2} q_3\n\\bar{q}_3$, e.g.\\ the $a_0(980)$ meson, the $D_{s0}^\\ast$ meson and some of the\ncharged $c \\bar{c}$ $X$ states. Some numerical results for the $a_0(980)$ meson\nare presented."
    },
    {
        "anchor": "Using a new analysis method to extract excited states in the scalar\n  meson sector: We explore a method to extract energy eigenstates, called Athens Model\nIndependent Analysis Scheme (AMIAS), which is an alternative to solving\nstandard Generalized Eigenvalue Problems (GEVP). The method is based on\nstatistically sampling the space of fit parameters according to the $\\chi^2$\nvalue of the fit function. The method is particularly suited for correlators or\ncorrelation matrices with strong contributions from several energy eigenstates\nand for rather noisy data, e.g. for correlators with disconnected and partly\ndisconnected diagrams. We apply the method to the analysis of the $J^P = 0^+$\nchannel in the context of our investigation of the $a_0(980)$ meson and point\nout advantages compared to the GEVP.",
        "positive": "Form Factors for B -> pi l nu-bar_l and B -> K* gamma Decays on the\n  Lattice: We present a unified method for analysing form factors in B -> pi l nu-bar_l\nand B -> K* gamma decays. The analysis provides consistency checks on the q^2\nand 1/M extrapolations necessary to obtain the physical decay rates. For the\nfirst time the q^2 dependence of the form factors is obtained at the B scale.\nIn the B -> pi l nu-bar_l case, we show that pole fits to f^+ may not be\nconsistent with the q^2 behaviour of f^0, leading to a possible factor of two\nuncertainty in the decay rate and hence in the value of |V_{ub}|^2 deduced from\nit. For B -> K* gamma, from the combined analysis of form factors T_1 and T_2,\nwe find the hadronisation ratio R_{K^*} of the exclusive B -> K* gamma to the\ninclusive b -> s gamma rates is of order 35% or 15% for constant and pole-type\nbehaviour of T_2 respectively."
    },
    {
        "anchor": "Sinle-valued and spinor representations of orientation-preserved\n  four-dimensional cubic group: We calculate the single-valued and spinor representations of $SO_4$, the\norientation-preserved subgroup of $O_4$, on the base of our previous work on\nfour-dimensional cubic group $O_4$.",
        "positive": "Landau Gauge Fixing on GPUs and String Tension: We explore the performance of CUDA in performing Landau gauge fixing in\nLattice QCD, using the steepest descent method with Fourier acceleration. The\ncode performance was tested in a Tesla C2070, Fermi architecture. We also\npresent a study of the string tension at finite temperature in the confined\nphase. The string tension is extracted from the color averaged free energy and\nfrom the color singlet using Landau gauge fixing."
    },
    {
        "anchor": "Local topological and chiral properties of QCD: To elucidate the role played by instantons in chiral symmetry breaking, we\nexplore their properties in full QCD, around the critical temperature. We study\nin particular spatial correlations between low-lying Dirac eigenmodes and\ninstantons. Our measurements are compared with the predictions of\ninstanton-based models.",
        "positive": "Supersymmetric QCD: Renormalization and Mixing of Composite Operators: We study $4$-dimensional SQCD with gauge group $SU(N_c)$ and $N_f$ flavors of\nchiral super-multiplets on the lattice. We perform extensive calculations of\nmatrix elements and renormalization factors of composite operators in\nPerturbation Theory. In particular, we compute the renormalization factors of\nquark and squark bilinears, as well as their mixing at the quantum level with\ngluino and gluon bilinear operators. From these results we construct correctly\nrenormalized composite operators, which are free of mixing effects and may be\nemployed in non-perturbative studies of Supersymmetry. All our calculations\nhave been performed with massive matter fields, in order to regulate the\ninfrared singularities which are inherent in renormalizing squark bilinears.\nFurthermore, the quark and squark propagators are computed in momentum space\nwith nonzero masses.\n  This work is a feasibility study for lattice computations relevant to a\nnumber of observables, such as spectra and distribution functions of hadrons,\nbut in the context of supersymmetric QCD, as a forerunner to lattice\ninvestigations of SUSY extensions of the Standard Model."
    },
    {
        "anchor": "Spectral Functions of Hadrons in Lattice QCD: Using the maximum entropy method, spectral functions of the pseudo-scalar and\nvector mesons are extracted from lattice Monte Carlo data of the imaginary time\nGreen's functions. The resonance and continuum structures as well as the ground\nstate peaks are successfully obtained. Error analysis of the resultant spectral\nfunctions is also given on the basis of the Bayes probability theory.",
        "positive": "Some effects of the anisotropy in a simple lattice gauge model at finite\n  temperature: Monte Carlo simulations are carried out on the (3+1)-dimensional Z(2)\nanisotropic lattice model, and a new method to simulate extremely anisotropic\nlattice systems with discrete symmetries is proposed. Dependence of the\ntemporal and spatial average plaquette, Wilson loops on the anisotropy\nparameter is presented."
    },
    {
        "anchor": "The static force from generalized Wilson loops on the lattice using\n  gradient flow: The static QCD force from the lattice can be used to extract\n$\\Lambda_{\\overline{\\textrm{MS}}}$, which determines the running of the strong\ncoupling. Usually, this is done with a numerical derivative of the static\npotential. However, this introduces additional systematic uncertainties; thus,\nwe use another observable to measure the static force directly. This observable\nconsists of a Wilson loop with a chromoelectric field insertion. We work in the\npure SU(3) gauge theory. We use gradient flow to improve the signal-to-noise\nratio and to address the field insertion. We extract\n$\\Lambda_{\\overline{\\textrm{MS}}}^{n_f=0}$ from the data by exploring different\nmethods to perform the zero flow time limit. We obtain the value $\\sqrt{8t_0}\n\\Lambda_{\\overline{\\textrm{MS}}}^{n_f=0} =0.629^{+22}_{-26}$, where $t_0$ is a\nflow time reference scale. We also obtain precise determinations of several\nscales: $r_0/r_1$, $\\sqrt{8 t_0}/r_0$, $\\sqrt{8 t_0}/r_1$ and we compare to the\nliterature. The gradient flow appears to be a promising method for calculations\nof Wilson loops with chromolectric and chromomagnetic insertions in quenched\nand unquenched configurations.",
        "positive": "Approaching $SU(2)$ gauge dynamics with smeared $Z(2)$ vortices: We present a method to smear (center projected) $Z(2)$ vortices in lattice\ngauge configurations such as to embed vortex physics into a full $SU(2)$ gauge\nconfiguration framework. In particular, we address the problem that using\n$Z(2)$ configurations in conjunction with overlap (or chirally improved)\nfermions is problematic due to their lack of smoothness. Our method allows us\nto regain this smoothness and simultaneously maintain the center vortex\nstructure. We verify our method with various gluonic and fermionic observables."
    },
    {
        "anchor": "Axial couplings in heavy hadron chiral perturbation theory at the\n  next-to-leading order: We present calculations of axial-current matrix elements between various\nheavy-meson and heavy-baryon states to the next-to-leading order in heavy\nhadron chiral perturbation theory in the p-regime. When compared with data from\nlattice computations or experiments, these results can be used to determine the\naxial couplings in the chiral Lagrangian. Our calculation is performed in\npartially-quenched chiral perturbation theory for both SU(4|2) and SU(6|3). We\nincorporate finite-size effects arising from a single Goldstone meson wrapping\naround the spatial volume. Results for full QCD with two and three flavours can\nbe obtained straightforwardly by taking the sea-quark masses to be equal to the\nvalence-quark masses. To illustrate the impact of our chiral perturbation\ntheory calculation on lattice computations, we analyse the SU(2) full QCD\nresults in detail. We also study one-loop contributions relevant to the heavy\nhadron strong-decay amplitudes involving final-state Goldstone bosons, and\ndemonstrate that the quark-mass dependence of these amplitudes can be\nsignificantly different from that of the axial current matrix elements\ncontaining only single hadron external states.",
        "positive": "Generalizing the relativistic quantization condition to include all\n  three-pion isospin channels: We present a generalization of the relativistic, finite-volume,\nthree-particle quantization condition for non-identical pions in isosymmetric\nQCD. The resulting formalism allows one to use discrete finite-volume energies,\ndetermined using lattice QCD, to constrain scattering amplitudes for all\npossible values of two- and three-pion isospin. As for the case of identical\npions considered previously, the result splits into two steps: The first\ndefines a non-perturbative function with roots equal to the allowed energies,\n$E_n(L)$, in a given cubic volume with side-length $L$. This function depends\non an intermediate three-body quantity, denoted $\\mathcal{K}_{\\mathrm{df},3}$,\nwhich can thus be constrained from lattice QCD input. The second step is a set\nof integral equations relating $\\mathcal{K}_{\\mathrm{df},3}$ to the physical\nscattering amplitude, $\\mathcal M_3$. Both of the key relations, $E_n(L)\n\\leftrightarrow \\mathcal{K}_{\\mathrm{df},3}$ and\n$\\mathcal{K}_{\\mathrm{df},3}\\leftrightarrow \\mathcal M_3$, are shown to be\nblock-diagonal in the basis of definite three-pion isospin, $I_{\\pi \\pi \\pi}$,\nso that one in fact recovers four independent relations, corresponding to\n$I_{\\pi \\pi \\pi}=0,1,2,3$. We also provide the generalized threshold expansion\nof $\\mathcal{K}_{\\mathrm{df},3}$ for all channels, as well as parameterizations\nfor all three-pion resonances present for $I_{\\pi\\pi\\pi}=0$ and\n$I_{\\pi\\pi\\pi}=1$. As an example of the utility of the generalized formalism,\nwe present a toy implementation of the quantization condition for\n$I_{\\pi\\pi\\pi}=0$, focusing on the quantum numbers of the $\\omega$ and $h_1$\nresonances."
    },
    {
        "anchor": "Centre vortex structure in the presence of dynamical fermions: An analysis of the geometry and structure of centre vortices in the presence\nof dynamical fermions is performed. A variety of metrics are used to measure\nthe matrix structure of the vortex-modified gauge fields. Visualisations of\ncentre vortices are presented and percolating clusters are identified. The size\nof secondary vortex clusters is analysed, with substantial differences observed\nbetween the pure Yang-Mills and dynamical fermion case. Vortex fields are\nrepresented as directed graphs, with branching points acting as the vertices.\nThis representation leads to a novel picture of vortex branching as a binomial\nprocess. These results elucidate the change in the centre vortex vacuum induced\nby the introduction of dynamical fermions.",
        "positive": "Charm Physics with Domain Wall Fermions and Physical Pion Masses: We present RBC/UKQCD's charm project using $N_f=2+1$ flavour ensembles with\ninverse lattice spacings in the range $1.73-2.77\\,\\mathrm{GeV}$ and two\nphysical pion mass ensembles. Domain wall fermions are used for the light as\nwell as the charm quarks. We discuss our strategy for the extraction of the\ndecay constants $f_D$ and $f_{D_s}$ and their extrapolation to the continuum\nlimit, physical pion masses and the physical heavy quark mass. Our preliminary\nresults are $f_D=208.7(2.8)\\,\\mathrm{MeV}$ and\n$f_{D_s}=246.4(1.9)\\,\\mathrm{MeV}$ where the quoted error is statistical only.\nWe outline our current approach to extend the reach in the heavy quark mass and\npresent preliminary results."
    },
    {
        "anchor": "Boundary condition for Staggered Fermion in Lattice Schr\u00f6dinger\n  Functional of QCD: The fermionic part of the Schr\\\"odinger functional of QCD is formulated in\nthe lattice regularization with the staggered fermion. The boundary condition\nimposed on the staggered fermion field are examined in terms of the\nfour-component Dirac spinor. The boundary terms are different from those of the\nSymanzik's theory in the flavor structure due to the species doubling. It is\nargued that, in the case of the homogeneous Dirichlet boundary condition,\nsurface divergence does not occur if the link variables of gauge field are\nintroduced on the original lattice, not on the blocked one. Its application to\nthe numerical calculation of the running coupling constant in QCD is discussed.",
        "positive": "Effective Field Theories for Quantum Chromodynamics on the Lattice: Light and heavy-light (b) hadrons are among the most interesting and among\nthe most challenging quantities to calculate in lattice gauge theory. One would\nlike to avoid discretization effects from very heavy quarks and to calculate\nchiral extrapolations and to calculate finite volume effects from light quarks\nor to minimize these effects. For this one uses effective theories: Chiral\nPerturbation Theory and Nonrelativistic QCD or Heavy Quark Effective Theory.\nLattice results are reviewed on hadrons containing light quarks and light and b\nquarks, and discussed in the framework of effective theories."
    },
    {
        "anchor": "Mass Determination from Constraint Effective Potential: The Constraint Effective Potential (CEP) allows a determination of the mass\nand other quantities directly, without relying upon asymptotic correlator\ndecays. We report and discuss the results of some mass calculations in\n$(\\lambda \\Phi^4)_4$, obtained from CEP and our improved version of CEP (ICEP).",
        "positive": "Further discussions on a possible lattice chiral gauge theory: In a possible $SU_L(2)$ lattice chiral gauge theory with a large multifermion\ncoupling, we try to further clarify the threshold phenomenon: the possibility\nthat the right-handed three-fermion state turns into the virtual states of its\nconstituents (free chiral fermions) in the low-energy limit. Provided this\nphenomenon occurs, we discuss the chiral gauge coupling, Ward identities and\nthe gauge anomaly within the gauge-invariant prescription of the perturbative\nchiral gauge theory."
    },
    {
        "anchor": "Interpreting the lattice monopoles in the continuum terms: We review briefly current interpretation of the lattice monopoles, defined\nwithin the Maximal Abelian Projection, in terms of the continuum theory. We\nemphasize, in particular, that the lattice data, at the presently available\nlattices, indicate that the monopoles are associated with singular fields. This\nnote is prompted by a recent analysis hep-lat/0211005 which is based on an\nimplicit assumption that the fields are regular.",
        "positive": "Effective Potential for Polyakov Loops in Lattice QCD: Toward the derivation of an effective theory for Polyakov loops in lattice\nQCD, we examine Polyakov loop correlation functions using the multi-level\nalgorithm which was recently developed by Luscher and Weisz."
    },
    {
        "anchor": "Singular gauge potentials and the gluon condensate at zero temperature: We consider a new cooling procedure which separates gluon degrees of freedom\nfrom singular center vortices in SU(2) LGT in a gauge invariant way. Restricted\nby a cooling scale $\\kappa^4/\\sigma^2$ fixing the residual SO(3) gluonic action\nrelative to the string tension, the procedure is RG invariant. In the limit\n$\\kappa \\to 0$ a pure Z(2) vortex texture is left. This {\\it minimal} vortex\ncontent does not contribute to the string tension. It reproduces, however, the\nlowest glueball states. With an action density scaling like $a^4$ with $\\beta$,\nit defines a finite contribution to the action density at T=0 in the continuum\nlimit. We propose to interpret this a mass dimension 4 condensate related to\nthe gluon condensate. Similarly, this vortex texture is revealed in the Landau\ngauge.",
        "positive": "Determination of the chiral condensate from QCD Dirac spectrum on the\n  lattice: We calculate the chiral condensate of QCD with 2, 2+1 and 3 flavors of sea\nquarks. Lattice QCD simulations are performed employing dynamical overlap\nfermions with up and down quark masses covering a range between 3 and 100 MeV.\nOn L ~ 1.8-1.9 fm lattices at a lattice spacing ~ 0.11 fm, we calculate the\neigenvalue spectrum of the overlap-Dirac operator. By matching the lattice data\nwith the analytical prediction from chiral perturbation theory at the\nnext-to-leading order, the chiral condensate in the massless limit of up and\ndown quarks is determined."
    },
    {
        "anchor": "The Infrared behaviour of the gluon propagator in SU(2) and SU(3)\n  without lattice Gribov copies: We present lattice results for the gluon propagator for SU(2) and SU(3) in\nthe Laplacian gauge which avoids lattice Gribov copies. In SU(3) we compare\nwith the most recent lattice calculation in Landau gauge and with various\napproximate solutions of the Dyson Schwinger equations (DSE).",
        "positive": "Matrix elements relevant for Delta I=1/2 rule and epsilon-prime from\n  Lattice QCD with staggered fermions: We perform a study of matrix elements relevant for the Delta I=1/2 rule and\nthe direct CP-violation parameter epsilon-prime from first principles by\ncomputer simulation in Lattice QCD. We use staggered (Kogut-Susskind) fermions,\nand employ the chiral perturbation theory method for studying K to 2 Pi decays.\nHaving obtained a reasonable statistical accuracy, we observe an enhancement of\nthe Delta I=1/2 amplitude, consistent with experiment within our large\nsystematic errors. Finite volume and quenching effects have been studied and\nwere found small compared to noise. The estimates of epsilon-prime are hindered\nby large uncertainties associated with operator matching. In this paper we\nexplain the simulation method, present the results and address the systematic\nuncertainties."
    },
    {
        "anchor": "Insight into the Scalar Mesons from a Lattice Calculation: We study the possibility that the light scalar mesons are (qbar qbar q q)\nstates rather than (qbar q). We perform a lattice QCD calculation of\npseudoscalar meson scattering amplitudes, ignoring quark loops and quark\nannihilation, and find indications that for sufficiently heavy quarks there is\na stable four-quark bound state with J^{PC}=0^{++} and non-exotic flavor\nquantum numbers.",
        "positive": "Topological sampling through windings: We propose a modification of the Hybrid Monte Carlo (HMC) algorithm that\novercomes the topological freezing of a two-dimensional $U(1)$ gauge theory\nwith and without fermion content. This algorithm includes reversible jumps\nbetween topological sectors$-$winding steps$-$combined with standard HMC steps.\nThe full algorithm is referred to as winding HMC (wHMC), and it shows an\nimproved behaviour of the autocorrelation time towards the continuum limit. We\nfind excellent agreement between the wHMC estimates of the plaquette and\ntopological susceptibility and the analytical predictions in the $U(1)$ pure\ngauge theory, which are known even at finite $\\beta$. We also study the\nexpectation values in fixed topological sectors using both HMC and wHMC, with\nand without fermions. Even when topology is frozen in HMC$-$leading to\nsignificant deviations in topological as well as non-topological\nquantities$-$the two algorithms agree on the fixed-topology averages. Finally,\nwe briefly compare the wHMC algorithm results to those obtained with\nmaster-field simulations of size $L\\sim 8 \\times 10^3$."
    },
    {
        "anchor": "Fermion Bag Approach for Massive Thirring Model at Finite Density: We consider the 2+1 dimensional massive Thirring model with one flavor at\nfinite density. Two numerical methods, fermion bag approach and complex\nLangevin dynamics, are used to calculate the chiral condensate and fermion\ndensity of this model. The numerical results obtained by fermion bag approach\nare compared with those obtained by complex Langevin dynamics. They are also\ncompared with those obtained under phase quenched approximation. We show that\nin some range of fermion coupling strength and chemical potential the sign\nproblem in fermion bag approach is mild, while it becomes severe for the\ncomplex Langevin dynamics.",
        "positive": "Chiral Fermions and Anomalies on a Finite Lattice: A recent proposal by Kaplan for a chiral gauge theory on the lattice is\ntested with background gauge fields. The spectrum of the finite lattice\nHamiltonian is calculated and the existence of a chiral fermion is\ndemonstrated. Lattice doublers are found to decouple. The flavor anomalies,\nwhich are in agreement with the continuum anomaly relation, are obeserved on a\nfinite lattice. Non-trivial anomaly cancellation is observed in a chiral gauge\ncurrent."
    },
    {
        "anchor": "Static quark anti-quark interactions at zero and finite temperature QCD.\n  II.Quark anti-quark internal energy and entropy: We analyze the change in free energy, internal energy and entropy due to the\npresence of a heavy quark anti-quark pair in a QCD heat bath. The internal\nenergies and entropies are introduced as intensive observables calculated\nthrough thermal derivatives of the QCD partition function containing additional\nstatic color sources. The quark anti-quark internal energy and, in particular,\nthe entropy clearly signal the phase change from quark confinement below and\ndeconfinement above the transition and both observables are introduced such\nthat they survive the continuum limit. The intermediate and large distance\nbehavior of the energies reflect string breaking and color screening phenomena.\nThis is used to characterize the energies which are needed to dissolve heavy\nquarkonium states in a thermal medium. Our discussion supports recent findings\nwhich suggest that parts of the quarkonium systems may survive the phase\ntransition and dissolve only at higher temperatures.",
        "positive": "Continuum Scaling from Large Mass Expansion on the Lattice: Delta\n  Expansion Applied to the Anharmonic Oscillator: We dilate the scaling region of the lattice anharmonic oscillator at strong\ncoupling by introducing the parameter delta. Performing expansion in delta, the\ncalculation of the mass gap in the continuum limit via the series expansion\neffective at large lattice spacings is then studied. We show that the dilation\non the mass parameter M recovers the scaling behavior of the hopping parameter\nbeta and allows for precise approximation of the mass gap."
    },
    {
        "anchor": "Spectral Flow and Index Theorem for Staggered Fermions: We investigate numerically the spectral flow introduced by Adams for the\nstaggered Dirac operator on realistic gauge configurations. We study both the\nunimproved and the HISQ Dirac operators. We compare the spectral flow index\nwith the index obtained by identifying low-lying modes of large chirality.",
        "positive": "Thermal monopole condensation in QCD with physical quark masses: Thermal monopoles, identified after Abelian projection as magnetic currents\nwrapping non-trivially around the thermal circle, are studied in $N_f = 2+1$\nQCD at the physical point. The distribution in the number of wrappings, which\nin pure gauge theories points to a condensation temperature coinciding with\ndeconfinement, points in this case to around 275 MeV, almost twice the QCD\ncrossover temperature $T_c$; similar indications emerge looking for the\nformation of a percolating current cluster. The possible relation with other\nnon-perturbative phenomena observed above $T_c$ is discussed."
    },
    {
        "anchor": "A lattice formulation of the Atiyah-Patodi-Singer index: Atiyah-Singer index theorem on a lattice without boundary is well understood\nowing to the seminal work by Hasenfratz et al. But its extension to the system\nwith boundary (the so-called Atiyah- Patodi-Singer index theorem), which plays\na crucial role in T-anomaly cancellation between bulk- and edge-modes in 3+1\ndimensional topological matters, is known only in the continuum theory and no\nlattice realization has been made so far. In this work, we try to\nnon-perturbatively define an alternative index from the lattice domain-wall\nfermion in 3+1 dimensions. We will show that this new index in the continuum\nlimit, converges to the Atiyah-Patodi-Singer index defined on a manifold with\nboundary, which coincides with the surface of the domain-wall.",
        "positive": "Color superconductivity in ultra-dense quark matter: At ultra-high density, matter is expected to form a degenerate Fermi gas of\nquarks in which there is a condensate of Cooper pairs of quarks near the Fermi\nsurface. This phenomenon is called color superconductivity. In these\nproceedings I review the underlying physics of color superconductivity and our\ncurrent understanding of the possible phases of real-world quark matter. Then I\nconsider how lattice gauge theorists would proceed to investigate the phase\nstructure of dense quark matter if it were possible to perform the path\nintegral numerically, i.e. if the sign problem had been solved."
    },
    {
        "anchor": "Y-type Flux-Tube Formation and Gluonic Excitations in Baryons: From QCD\n  to Quark Model: Using SU(3) lattice QCD, we perform the first systematic study for the\nground-state three-quark (3Q) potential $V_{\\rm 3Q}^{\\rm g.s.}$ and the 1st\nexcited-state 3Q potential $V_{\\rm 3Q}^{\\rm e.s.}$, {\\it i.e.}, the energies of\nthe ground state and the 1st excited state of the gluon field in the presence\nof the static three quarks. From the accurate and thorough calculation for more\nthan 300 different patterns of 3Q systems, the static ground-state 3Q potential\n$V_{\\rm 3Q}^{\\rm g.s.}$ is found to be well described by the Coulomb plus\nY-type linear potential, {\\it i.e.}, Y-Ansatz, within 1%-level deviation. As a\nclear evidence for Y-Ansatz, Y-type flux-tube formation is actually observed on\nthe lattice in maximally-Abelian projected QCD. For more than 100 patterns of\n3Q systems, we calculate the 1st excited-state 3Q potential $V_{\\rm 3Q}^{\\rm\ne.s.}$ in quenched lattice QCD, and find the gluonic excitation energy $\\Delta\nE_{\\rm 3Q} \\equiv V_{\\rm 3Q}^{\\rm e.s.}-V_{\\rm 3Q}^{\\rm g.s.}$ to be about 1\nGeV. This large gluonic-excitation energy is conjectured to ensure the success\nof the quark model for the low-lying hadrons even without gluonic excitations.",
        "positive": "Flow-based density of states for complex actions: Emerging sampling algorithms based on normalizing flows have the potential to\nsolve ergodicity problems in lattice calculations. Furthermore, it has been\nnoted that flows can be used to compute thermodynamic quantities which are\ndifficult to access with traditional methods. This suggests that they are also\napplicable to the density-of-states approach to complex action problems. In\nparticular, flow-based sampling may be used to compute the density directly, in\ncontradistinction to the conventional strategy of reconstructing it via\nmeasuring and integrating the derivative of its logarithm. By circumventing\nthis procedure, the accumulation of errors from the numerical integration is\navoided completely and the overall normalization factor can be determined\nexplicitly. In this proof-of-principle study, we demonstrate our method in the\ncontext of two-component scalar field theory where the $O(2)$ symmetry is\nexplicitly broken by an imaginary external field. First, we concentrate on the\nzero-dimensional case which can be solved exactly. We show that with our\nmethod, the Lee-Yang zeroes of the associated partition function can be\nsuccessfully located. Subsequently, we confirm that the flow-based approach\ncorrectly reproduces the density computed with conventional methods in one- and\ntwo-dimensional models."
    },
    {
        "anchor": "Threshold expansion formula of $N$-boson in finite volume from\n  variational approach: In present work, we show how the threshold expansion formula of $N$ identical\nbosons in finite volume may be derived by iterations of Faddeev-type coupled\ndynamical equations. The energy shift of $N$-boson system near threshold is\ndominated by zero momenta mode of $N$-body amplitudes with all particles nearly\nstatic. The dominant zero momenta mode and sub-leading non-zero momenta mode\ncontributions are connected through finite volume Faddeev-type coupled\ndynamical equations. Eliminating non-zero momenta modes by iterations\nultimately yields an analytic expression that can be solved by threshold\nexpansion.",
        "positive": "Evidence for discrete chiral symmetry breaking in N=1 supersymmetric\n  Yang-Mills theory: In a numerical Monte Carlo simulation of SU(2) Yang-Mills theory with\ndynamical gauginos we find evidence for two degenerate ground states at the\nsupersymmetry point corresponding to zero gaugino mass. This is consistent with\nthe expected pattern of spontaneous discrete chiral symmetry breaking $Z_4 \\to\nZ_2$ caused by gaugino condensation."
    },
    {
        "anchor": "New results for thermal interquark bottomonium potentials using NRQCD\n  from the HAL QCD method: We report progress in the calculation of the thermal interquark potential of\nbottomonium using the HAL QCD method applied to bottom quarks in the\nnon-relativistic approximation (i.e. NRQCD). We exploit the fast Fourier\ntransform algorithm, using a momentum space representation, to efficiently\ncalculate NRQCD correlation functions of non-local mesonic S-wave states, and\nthus obtain the potential for temperatures in both the hadronic and plasma\nphases. This work was performed on our anisotropic 2+1 flavour ''Generation 2''\nFASTSUM ensembles.",
        "positive": "Constraining the gauge-fixed Lagrangian in minimal Landau gauge: A continuum formulation of gauge-fixing resolving the Gribov-Singer ambiguity\nremains a challenge. Finding a Lagrangian formulation of operational\nresolutions in numerical lattice calculations, like minimal Landau gauge, would\nbe one possibility. Such a formulation will here be constrained by\nreconstructing the Dyson-Schwinger equation for which the lattice\nminimal-Landau-gauge ghost propagator is a solution. It is found that this\nrequires an additional term. As a by-product new, high precision lattice\nresults for the ghost-gluon vertex in three and four dimensions are obtained."
    },
    {
        "anchor": "Proton mass decomposition: We report the results on the proton mass decomposition and also on the\nrelated quark and glue momentum fractions. The results are based on overlap\nvalence fermions on four ensembles of $N_f = 2+1$ DWF configurations with three\nlattice spacings and volumes, and several pion masses including the physical\npion mass. With 1-loop perturbative calculation and proper normalization of the\nglue operator, we find that the $u, d,$ and $s$ quark masses contribute 9(2)\\%\nto the proton mass. The quark energy and glue field energy contribute 31(5)\\%\nand 37(5)\\% respectively in the $\\overline{MS}$ scheme at $\\mu = 2$ GeV. The\ntrace anomaly gives the remaining 23(1)\\% contribution. The $u,d,s$ and glue\nmomentum fractions in the $\\overline{MS}$ scheme are consistent with the global\nanalysis at $\\mu = 2$ GeV.",
        "positive": "Quenched QCD with fixed-point and chirally improved fermion: In this contribution we present results from quenched QCD simulations with\nthe parameterized fixed-point (FP) and the chirally improved (CI) Dirac\noperator. Both these operators are approximate solutions of the Ginsparg-Wilson\nequation and have good chiral properties. We focus our discussion on\nobservables sensitive to chirality. In particular we explore pion masses down\nto 210 MeV in light hadron spectroscopy, quenched chiral logs, the pion decay\nconstant and the pion scattering length. We discuss finite volume effects,\nscaling properties of the FP and CI operators and performance issues in their\nnumerical implementation."
    },
    {
        "anchor": "QCD with one compact spatial dimension: The realization of global symmetries can depend on the geometry of the\nunderlying space. In particular, compactification can lead to spontaneous\nbreaking of such symmetries. Four-dimensional QCD with fundamental\nrepresentation fermions embedded in a space with one compact spatial dimension\nhas a critical length, at which the theory undergoes a phase transition and\ndevelops a ground state that is no longer charge conjugation invariant. We show\nthis behavior with simulations of three color, four flavor QCD. We use unrooted\nstaggered fermion at two values of the lattice spacing and several quark\nmasses. We discuss the dependence of the transition on the dynamical fermion\nmass as well as its connection to the finite temperature and chiral phase\ntransitions.",
        "positive": "Gradient flow running coupling in SU(2) Nf=6 flavors: We present preliminary results of the running of the coupling in SU(2) gauge\ntheory with 6 massless fundamental representation fermion flavors. We measure\nthe coupling using the gradient flow method with Schr\\\"odinger functional\nboundary conditions. The results are consistent with the perturbation theory in\nthe weak coupling and we see an indication of an infrared fixed point at strong\ncoupling."
    },
    {
        "anchor": "Applying constrained simulations for low temperature lattice QCD at\n  finite baryon chemical potential: We study the density of states method as well as reweighting to explore the\nlow temperature phase diagram of QCD at finite baryon chemical potential. We\nuse four flavors of staggered quarks, a tree-level Symanzik improved gauge\naction and four stout smearing steps on lattices with $N_s=4,6,8$ and $N_t=6 -\n16$. We compare our results to that of the phase quenched ensemble and also\ndetermine the pion and nucleon masses. In the density of states approach we\napplied pion condensate or gauge action density fixing. We found that the\ndensity of states method performs similarly to reweighting. At $T \\approx 100$\nMeV, we found an indication of the onset of the quark number density at around\n$\\mu/m_N \\sim 0.16 - 0.18$ on $6^4$ lattices at $\\beta=2.9$.",
        "positive": "Chiral Defect Fermions and the Layered Phase: Chiral defect fermions on the lattice in 4+1 dimensions are analyzed using\nmean field theory. The fermion propagator has a localized chiral mode in weak\ncoupling but loses it when the coupling in the unphysical fifth direction\nbecomes too large. A layered phase \\`a la Fu-Nielsen appears where the theory\nis vector-like in every layer."
    },
    {
        "anchor": "First study of the gluon-quark-antiquark static potential in SU(3)\n  Lattice QCD: We study the long distance interaction for hybrid hadrons, with a static\ngluon, a quark and an antiquark with lattice QCD techniques. A Wilson loop\nadequate to the static hybrid three-body system is developed and, using a 24^3\nx 48 periodic lattice with beta=6.2 and a ~ 0.075 fm, two different geometries\nfor the gluon-quark segment and the gluon-antiquark segment are investigated.\nWhen these segments are perpendicular, the static potential is compatible with\nconfinement realized with a pair of fundamental strings, one linking the gluon\nto the quark and another linking the same gluon to the antiquark. When the\nsegments are parallel and superposed, the total string tension is larger and\nagrees with the Casimir Scaling measured by Bali. This can be interpreted with\na type-II superconductor analogy for the confinement in QCD, with repulsion of\nthe fundamental strings and with the string tension of the first topological\nexcitation of the string (the adjoint string) larger than the double of the\nfundamental string tension.",
        "positive": "Phase Transitions in Two-Dimensional Traffic Flow Models: We introduce two simple two-dimensional lattice models to study traffic flow\nin cities. We have found that a few basic elements give rise to the\ncharacteristic phase diagram of a first-order phase transition from a freely\nmoving phase to a jammed state, with a critical point. The jammed phase\npresents new transitions corresponding to structural transformations of the\njam. We discuss their relevance in the infinite size limit."
    },
    {
        "anchor": "Spectrum and Wave Functions of Excited States in Lattice Gauge Theory: We suggest a new method to compute the spectrum and wave functions of excited\nstates. We construct a stochastic basis of Bargmann link states, drawn from a\nphysical probability density distribution and compute transition amplitudes\nbetween stochastic basis states. From such transition matrix we extract wave\nfunctions and the energy spectrum. We apply this method to $U(1)_{2+1}$ lattice\ngauge theory. As a test we compute the energy spectrum, wave functions and\nthermodynamical functions of the electric Hamiltonian and compare it with\nanalytical results. We find excellent agreement. We observe scaling of energies\nand wave functions in the variable of time. We also present first results on a\nsmall lattice for the full Hamiltonian including the magnetic term.",
        "positive": "Octet baryon mass splittings from up-down quark mass differences: Using an SU(3) flavour symmetry breaking expansion in the quark mass, we\ndetermine the QCD component of the neutron-proton, Sigma and Xi mass splittings\nof the baryon octet due to up-down (and strange) quark mass differences.\nProvided the average quark mass is kept constant, the expansion coefficients in\nour procedure can be determined from computationally cheaper simulations with\nmass degenerate sea quarks and partially quenched valence quarks. Full details\nand numerical results are given in ref 1."
    },
    {
        "anchor": "Quark Confinement in the Deconfined Phase: In cylindrical volumes with C-periodic boundary conditions in the long\ndirection, static quarks are confined even in the gluon plasma phase due to the\npresence of interfaces separating the three distinct high-temperature phases.\nAn effective \"string tension\" is computed analytically using a dilute gas of\ninterfaces. At T_c, the deconfined-deconfined interfaces are completely wet by\nthe confined phase and the high-temperature \"string tension\" turns into the\nusual string tension below T_c. Finite size formulae are derived, which allow\nto extract interface and string tensions from the expectation value of a single\nPolyakov loop. A cluster algorithm is built for the 3-d three-state Potts model\nand an improved estimator for the Polyakov loop is constructed, based on the\nnumber of clusters wrapping around the C-periodic direction of the cluster.",
        "positive": "Nucleon isovector couplings from 2+1 flavor lattice QCD at the physical\n  point: We present results on the axial, scalar and tensor isovector-couplings of the\nnucleon from 2+1 flavor lattice QCD with physical light quarks ($m_\\pi$ = 135\nMeV) in large spatial volume of (10.8 fm)$^3$. The calculations are carried out\nwith the PACS10 gauge configurations generated by the PACS Collaboration with\nthe stout-smeared $\\mathcal{O}(a)$ improved Wilson fermions and Iwasaki gauge\naction at $\\beta=1.82$ corresponding to the lattice spacing of 0.084 fm. For\nthe renormalization, we use the RI/SMOM scheme, a variant of Rome-Southampton\nRI/MOM scheme with reduced systematic errors, as the intermediate scheme. We\nthen evaluate our final results in the $\\overline{\\rm MS}$ scheme at a scale of\n2 GeV, using the continuum perturbation theory for the matching scale of\nRI/SMOM and $\\overline{\\rm MS}$ schemes and running."
    },
    {
        "anchor": "Chiralspin symmetry and confinement: Interesting lattice QCD simulations at high temperature in QCD and particular\ntruncated studies have shown the emergence of an unexpected group symmetry, so\ncalled \\textit{chiralspin}. However this is not a symmetry of the QCD action\nfor free quarks, which makes unclear the transition to deconfinement at high\ntemperature in QCD. Therefore we try to redefine this group so that is a\nsymmetry of free quark action and it is consistent with the presence of\ndeconfinement in QCD.",
        "positive": "Gauge theory of things alive and universal dynamics: Positing complex adaptive systems made of agents with relations between them\nthat can be composed, it follows that they can be described by gauge theories\nsimilar to elementary particle theory and general relativity. By definition, a\nuniversal dynamics is able to determine the time development of any such system\nwithout need for further specification. The possibilities are limited, but one\nof them - reproduction fork dynamics - describes DNA replication and is the\nbasis of biological life on earth. It is a universal copy machine and a\nrenormalization group fixed point. A universal equation of motion in continuous\ntime is also presented."
    },
    {
        "anchor": "Calculation of BSM Kaon B-parameters using Staggered Quarks: We present updated results for kaon B-parameters for operators arising in\nmodels of new physics. We use HYP-smeared staggered quarks on the $N_f = 2+1$\nMILC asqtad lattices. During the last year we have added new ensembles, which\nhas necessitated chiral-continuum fitting with more elaborate fitting\nfunctions. We have also corrected an error in a two-loop anomalous dimension\nused to evolve results between different scales. Our results for the\nbeyond-the-Standard-Model B-parameters have total errors of $5-10$\\%. We find\nthat the discrepancy observed last year between our results and those of the\nRBC/UKQCD and ETM collaborations for some of the B-parameters has been reduced\nfrom $4\\!-\\!5\\,\\sigma$ to $2\\!-\\!3\\,\\sigma$.",
        "positive": "Confinement and Chiral Symmetry, a Lattice QCD test of AdS/QCD: We use lattice QCD simulations to test some of the predictions of proposed\nAdS/QCD (holographic) duals for QCD. In particular, these duals predict that\nthe scale of chiral symmetry breaking ($\\chi$SB) can be varied independently\nfrom that of confinement, with the proviso that the scale of $\\chi$SB cannot be\nlonger than that of confinement. We simulate lattice QCD with 2 quarks in the\nfundamental representation of colour and with additional 4-fermion interactions\n(suggested by AdS/QCD), at finite temperatures. For sufficiently strong\n4-fermion interactions, the deconfinement and $\\chi$SB transitions occur at\ndifferent temperatures, the separation depending on the 4-fermion coupling.\nThis confirms that the scales of confinement and $\\chi$SB are, in general,\ndifferent."
    },
    {
        "anchor": "Distance between various discretized fermion actions: We present the leading order mixed-action effect $\\Delta_{\\rm mix}\\equiv\nm_{\\pi,{\\rm vs}}^2-\\frac{m_{\\pi,{\\rm vv}}^2+m_{\\pi,{\\rm ss}}^2}{2}$ using HISQ,\nclover or overlap valence fermion actions on gauge ensembles using various sea\nfermion actions across a widely-used lattice spacing range $a\\in\n[0.04,0.19]$~fm. The results suggest that $\\Delta_{\\rm mix}$ decreases as the\nfourth order of the lattice spacing on the gauge ensembles with dynamical\nchiral sea fermions, such as Domain wall or HISQ fermions. When a clover sea\nfermion action which has explicit chiral symmetry breaking is used in the\nensemble, $\\Delta_{\\rm mix}$ can be much larger regardless of the valence\nfermion action used.",
        "positive": "Yang-Mills Ground State in 2+1 Dimensions and Temporal Gauge: A gauge-invariant wavefunctional is proposed as an approximation to the\nground state of Yang-Mills theory in 2+1 dimensions, quantized in temporal\ngauge. The proposed vacuum state is the true ground state of the appropriate\nHamiltonian in both the free-field limit, and in a zero mode strong-field\nlimit. Confinement, in this approach, arises via dimensional reduction, and we\npresent numerical results for the mass gap. The issue of color screening is\nbriefly discussed."
    },
    {
        "anchor": "Multi-Polynomial Monte Carlo for Trace Estimation in Lattice QCD: Estimating the trace of the inverse of a large matrix is an important problem\nin lattice quantum chromodynamics. A multilevel Monte Carlo method is proposed\nfor this problem that uses different degree polynomials for the levels. The\npolynomials are developed from the GMRES algorithm for solving linear\nequations. To reduce orthogonalization expense, the highest degree polynomial\nis a composite or double polynomial found with a polynomial preconditioned\nGMRES iteration. Added to some of the Monte Carlo pieces is deflation of\neigenvalues that reduces the variance. Deflation is also used for finding a\nreduced degree deflated polynomial. The new Multipolynomial Monte Carlo method\ncan significantly improve the trace computation for matrices that have a\ndifficult spectrum due to small eigenvalues.",
        "positive": "Lessons from the 3d U(1) Gross-Neveu Model: The effectiveness of the Glasgow algorithm is explored via implementation in\nthe 3d U(1) Gross-Neveu model and the realisation of the Goldstone mechanism in\nthis model is compared and contrasted with its realisation in QCD."
    },
    {
        "anchor": "APEmille: a parallel processor in the teraflop range: APEmille is a SIMD parallel processor under development at the Italian\nNational Institute for Nuclear Physics (INFN). APEmille is very well suited for\nLattice QCD applications, both for its hardware characteristics and for its\nsoftware and language features. APEmille is an array of custom arithmetic\nprocessors arranged on a tridimensional torus. The replicated processor is a\npipelined VLIW device performing integer and single/double precision IEEE\nfloating point operations. The processor is optimized for complex computations\nand has a peak performance of 528Mflop at 66MHz and of 800Mflop at 100MHz. In\nprinciple an array of 2048 nodes is able to break the Tflops barrier. A\npowerful programming language named TAO is provided and is highly optimized for\nQCD. A C++ compiler is foreseen. Specific data structures, operators and even\nstatements can be defined by the user for each different application. Effort\nhas been made to define the language constructs for QCD.",
        "positive": "Mass anomalous dimension from Dirac eigenmode scaling in conformal and\n  confining systems: The mode number of the Dirac operator scales with an exponent related to the\nmass anomalous dimension gamma_m. This relation holds both in IR-conformal\nsystems, as well as in confining systems for large enough eigenvalues. We\ninvestigate the Nf=4, 8 and 12 flavor SU(3) systems at several couplings near\nthe chiral limit, and show that in general the scaling exponent varies with the\neigenvalue, describing the dependence of gamma_m on the energy (or,\nequivalently, on the running coupling). This energy dependence can be explored\neven with fixed lattice parameters (bare coupling and mass). We find that for\nthe 4 flavor system the mass anomalous dimension decreases as the energy\nincreases, consistent with perturbative expectations. For the 8 flavor system\nthe energy dependence is too weak to be observable at present. The 12 flavor\nsystem at our strongest couplings shows the anomalous dimension increasing with\nenergy, consistent with backward flow and the presence of an infrared fixed\npoint. At weaker couplings we determine a preliminary value for the mass\nanomalous dimension of the 12 flavor system at the infrared fixed point,\ngamma_m^*=0.27(3)."
    },
    {
        "anchor": "Multigrid accelerated simulations for Twisted Mass fermions: Simulations at physical quark masses are affected by the critical slowing\ndown of the solvers. Multigrid preconditioning has proved to deal effectively\nwith this problem. Multigrid accelerated simulations at the physical value of\nthe pion mass are being performed to generate $N_f = 2$ and $N_f = 2 + 1 + 1$\ngauge ensembles using twisted mass fermions. The adaptive aggregation-based\ndomain decomposition multigrid solver, referred to as DD-$\\alpha$AMG method, is\nemployed for these simulations. Our simulation strategy consists of an hybrid\napproach of different solvers, involving the Conjugate Gradient (CG),\nmulti-mass-shift CG and DD-$\\alpha$AMG solvers. We present an analysis of the\nmultigrid performance during the simulations discussing the stability of the\nmethod. This significant speeds up the Hybrid Monte Carlo simulation by more\nthan a factor $4$ at physical pion mass compared to the usage of the CG solver.",
        "positive": "A novel gauge invariant multi-state smearing technique: We present an investigation of a gauge invariant smearing technique that\nallows the construction of smearing functions with arbitrary radial behaviour,\nby foresaking the space filling nature of traditional smearing techniques. This\nis applied to both heavy-heavy, heavy-light, and light-light systems with one\nparticular choice of radial ``wavefunction'' - the hydrogenic solutions - and\nwe find good stability for both fitted masses and amplitudes of the radially\nexcited states. The dependence of the amplitudes on the smearing radius is\ndemonstrated to be well understood, while near optimal smearing radii may be\nfound with extremely low statistics using a property of the smeared-local\ncorrelator. The smearing technique is inexpensive since it is non-iterative,\nachieves a good signal to noise ratio, and can be altered to use wavefunctions\nfrom, say, potential models or the Bethe-Salpether equations in future\nsimulations."
    },
    {
        "anchor": "Twisted Mass Finite Volume Effects: We calculate finite volume effects on the pion masses and decay constant in\ntwisted mass lattice QCD (tmLQCD) at finite lattice spacing. We show that the\nlighter neutral pion in tmLQCD gives rise to finite volume effects that are\nexponentially enhanced when compared to those arising from the heavier charged\npions. We demonstrate that the recent two flavour twisted mass lattice data can\nbe better fitted when twisted mass effects in finite volume corrections are\ntaken into account.",
        "positive": "A nucleon in a tiny box: We use Chiral Perturbation Theory to compute the nucleon mass-shift due to\nfinite volume and temperature effects. Our results are valid up to\nnext-to-leading order in the \"\\eps-regime\" (mL ~ m\\beta << 1) as well as in the\n\"p-regime\" (mL ~ m\\beta >> 1). Based on the two leading orders, we discuss the\nconvergence of the expansion as a function of the lattice size and quark\nmasses. This result can be used to extrapolate lattice results obtained from\nlattice sizes smaller than the pion cloud, avoiding the numerical simulation of\nphysics under theoretical control. An extraction of the low-energy coefficient\nc_3 of the chiral Lagrangean from lattice simulations at small volumes and a\n``magic'' ratio \\beta=1.22262 L might be possible."
    },
    {
        "anchor": "Topical Results on Lattice Chiral Fermions in the CFA: We report new results on the lattice regularization of the chiral Schwinger\nmodel and the chiral U(1) model in four dimensions in the CFA.",
        "positive": "Effective string description of the interquark potential in the 3D U(1)\n  lattice gauge theory: The U(1) lattice gauge theory in three dimensions is a perfect laboratory to\nstudy the properties of the confining string. On the one hand, thanks to the\nmapping to a Coulomb gas of monopoles, the confining properties of the model\ncan be studied semi-classically. On the other hand, high-precision numerical\nestimates of Polyakov loop correlators can be obtained via a duality map to a\nspin model. This allowed us to perform high-precision tests of the universal\nbehavior of the effective string and to find macroscopic deviations with\nrespect to the expected Nambu-Goto predictions. These corrections could be\nfitted with very good precision including a contribution (which is consistent\nwith Lorentz symmetry) proportional to the square of the extrinsic curvature in\nthe effective string action, as originally suggested by Polyakov. Performing\nour analysis at different values of $\\beta$ we were able to show that this term\nscales as expected by Polyakov's solution and dominates in the continuum. We\nalso discuss the interplay between the extrinsic curvature contribution and the\nboundary correction induced by the Polyakov loops."
    },
    {
        "anchor": "The phase structure of a chirally invariant lattice Higgs-Yukawa model -\n  numerical simulations: The phase diagram of a chirally invariant lattice Higgs-Yukawa model is\nexplored by means of numerical simulations. The results revealing a rich phase\nstructure are compared to analytical large Nf calculations which we performed\nearlier. The analytical and numerical results are in excellent agreement at\nlarge values of Nf. In the opposite case the large Nf computation still gives a\ngood qualitative description of the phase diagram. In particular we find\nnumerical evidence for the predicted ferrimagnetic phase at intermediate values\nof the Yukawa coupling constant and for the symmetric phase at strong Yukawa\ncouplings. Emphasis is put on the finite size effects which can hide the\nexistence of the latter symmetric phase.",
        "positive": "Accurate simulation of the finite density lattice Thirring model: We present a study of the finite density lattice Thirring model in 1+1\ndimensions using the world-line/fermion-bag algorithm. The model has features\nsimilar to QCD and provides a test case for exploring the accuracy of various\nmethods of solving sign problems. In the massless limit and with open boundary\nconditions we show that the sign problem is an artifact of the auxiliary field\napproach and is completely eliminated in the fermion bag approach. With\nperiodic boundary conditions the sign problem is mild in the fermion bag\nmethod. We present accurate results for various quantities in the model that\ncan be used as a benchmark for comparison with other methods of solving sign\nproblems."
    },
    {
        "anchor": "Interaction potential in compact three-dimensional QED with mixed action: We use a variational wave function to calculate the energy of the interaction\nbetween external charges in the compact Abelian gauge theory in 2+1 dimensions\nwith mixed action. Our variational wave functions preserve the compact gauge\ninvariance of the theory both in the vacuum and in the charged sectors. We find\nthat a good estimate of the interaction energy is obtained only when we allow\nmore variational parameters in the charged sector than in the vacuum sector.\nThese extra parameters are the profile of an induced electric field. We find\nthat the theory has a two-phase structure: When the charge-2 coupling is large\nand negative there is no mass gap in the theory and no confinement, while\notherwise a mass gap is generated dynamically and the theory confines charges.\nThe pure Wilson theory is in the confining phase.",
        "positive": "Weak Matrix Elements of Beyond the Standard Model $\u0394s=2$\n  four-quark operators from nf=2+1 Domain-Wall fermions: We report on our computation of the hadronic matrix elements of the\nfour-quark operators needed for the study of $K^0-{\\bar K^0}$ mixing beyond the\nStandard Model (SM). We consider nf=2+1 Domain-Wall fermions on Iwasaki gauge\naction with lightest unitary pion of 290 MeV and a single lattice spacing\na=0.086 fm. The renormalization is performed non-perturbatively through the\nRI-MOM scheme and our results are converted perturbatively to MSbar. We have\nestimated the various systematic errors. Our results confirm a previous\nquenched study, where large ratios of non-SM to SM matrix elements were\nobtained."
    },
    {
        "anchor": "Effects of magnetic fields on quark-antiquark interactions: We discuss some recent results obtained in the study of strong\nquark-antiquark interactions in the presence of intense external magnetic\nfields by means of lattice QCD simulations. We confirm previous findings and\nshow that both at zero and finite temperature the external field induces\nanisotropies in the static quark potential. An in-depth study suggests that the\neffects are essentially due to the variation of the string tension whose\nangular dependence can be nicely parametrized by the first allowed term in a\nFourier expansion. In the confined phase at high temperature, we observe that\nthe suppression of the string tension is enhanced as the strength of the\nexternal field increases. Our results support the idea that the loss of\nconfining properties is the dominant effect related to the decrease of $T_c$ as\na function of $B$.",
        "positive": "Discretized Laplacians on an Interval and their Renormalization Group: The Laplace operator admits infinite self-adjoint extensions when considered\non a segment of the real line. They have different domains of essential\nself-adjointness characterized by a suitable set of boundary conditions on the\nwave functions. In this paper we show how to recover these extensions by\nstudying the continuum limit of certain discretized versions of the Laplace\noperator on a lattice. Associated to this limiting procedure, there is a\nrenormalization flow in the finite dimensional parameter space describing the\ndicretized operators. This flow is shown to have infinite fixed points,\ncorresponding to the self-adjoint extensions characterized by scale invariant\nboundary conditions. The other extensions are recovered by looking at the other\ntrajectories of the flow."
    },
    {
        "anchor": "An Exploratory Study of Nucleon-Nucleon Scattering Lengths in Lattice\n  QCD: An exploratory study is made of the nucleon-nucleon $s$-wave scattering\nlengths in quenched lattice QCD with the Wilson quark action. The $\\pi$-$N$ and\n$\\pi$-$\\pi$ scattering lengths are also calculated for comparison. The\ncalculations are made with heavy quarks corresponding to $m_\\pi/m_\\rho\\approx\n0.73-0.95$. The results show that the $N$-$N$ system has an attractive force in\nboth spin-singlet and triplet channels, with their scattering lengths\nsignificantly larger than those for the $\\pi$-$N$ and $\\pi$-$\\pi$ cases, a\ntrend which is qualitatively consistent with the experiment. Problems toward a\nmore realistic calculation for light quarks are discussed.",
        "positive": "Spin 3/2 Penta-quarks in anisotropic lattice QCD: A high-precision mass measurement for the pentaquark (5Q) Theta^+ in\nJ^P=3/2^{\\pm} channel is performed in anisotropic quenched lattice QCD using a\nlarge number of gauge configurations as N_{conf}=1000. We employ the standard\nWilson gauge action at beta=5.75 and the O(a) improved Wilson (clover) quark\naction with kappa=0.1210(0.0010)0.1240 on a 12^3 \\times 96 lattice with the\nrenormalized anisotropy as a_s/a_t = 4. The Rarita-Schwinger formalism is\nadopted for the interpolating fields. Several types of the interpolating fields\nwith isospin I=0 are examined such as (a) the NK^*-type, (b) the\n(color-)twisted NK^*-type, (c) a diquark-type. The chiral extrapolation leads\nto only massive states, i.e., m_{5Q} \\simeq 2.1-2.2 GeV in J^P=3/2^- channel,\nand m_{5Q} = 2.4-2.6 GeV in J^P=3/2^+ channel. The analysis with the hybrid\nboundary condition(HBC) is performed to investigate whether these states are\ncompact 5Q resonances or not. No low-lying compact 5Q resonance states are\nfound below 2.1GeV."
    },
    {
        "anchor": "$m_c$ (and $m_b$) from lattice QCD: Quark mass determinations based on lattice QCD simulations have continued to\nmake strides in recent years. Here I review that progress with a focus on\ndevelopments computing the charm (and bottom) quark masses since the 2015\nedition of CHARM. These advances have resulted in groups now quoting\n(sub-)percent-level precision for these quantities, and, importantly, using a\nvariety of techniques subject to differing systematic uncertainties.\nImprovements to quantify the effects of QED are also now being included. I will\nhighlight three of the strategies being used to determine $m_c$ at this level\nof precision.",
        "positive": "Improving dynamical lattice QCD simulations through integrator tuning\n  using Poisson brackets and a force-gradient integrator: We show how the integrators used for the molecular dynamics step of the\nHybrid Monte Carlo algorithm can be further improved. These integrators not\nonly approximately conserve some Hamiltonian $H$ but conserve exactly a nearby\nshadow Hamiltonian $\\tilde{H}$. This property allows for a new tuning method of\nthe molecular dynamics integrator and also allows for a new class of\nintegrators (force-gradient integrators) which is expected to reduce\nsignificantly the computational cost of future large-scale gauge field ensemble\ngeneration."
    },
    {
        "anchor": "Efficient vacuum state preparation for quantum simulation of strongly\n  interacting local quantum field theories: We present an efficient approach for preparing ground states in the context\nof strongly interacting local quantum field theories on quantum computers. The\napproach produces the vacuum state in a time proportional to the square-root of\nthe volume, which is a square-root improvement in speed compared to traditional\napproaches. The approach exploits a novel method for traversing the path in\nparameter space in which the resources scale linearly with a path length\nsuitably defined in parameter space. Errors due to practical limitations are\ncontrolled and do not exhibit secular growth along the path. The final accuracy\ncan be arbitrarily improved with an additive cost, which is independent of the\nvolume and grows slower than logarithmically with the overlap between the state\nproduced and the exact ground state. We expect that the method could\npotentially hold practical value not only within the realm of quantum field\ntheories but also in addressing other challenges involving long path lengths.",
        "positive": "Twisted Mass, Overlap and Creutz Fermions: Cut-off Effects at Tree-level\n  of Perturbation Theory: We study cutoff effects at tree-level of perturbation theory for maximally\ntwisted mass Wilson, overlap and the recently proposed Creutz fermions. We\ndemonstrate that all three kind of lattice fermions exhibit the expected O(a^2)\nscaling behaviour in the lattice spacing. In addition, the sizes of these\ncutoff effects are comparable for the three kinds of lattice fermions\nconsidered here. Furthermore, we analyze situations when twisted mass fermions\nare not exactly at maximal twist and when overlap fermions are studied in\ncomparison to twisted mass fermions when the quark masses are not matched."
    },
    {
        "anchor": "Overlap for Majorana-Weyl fermions: The power of the overlap formalism is illustrated by regularizing theories\nbased on Majorana-Weyl fermions.",
        "positive": "A lattice QCD study of the $B \\to \u03c0\u03c0\\ell \\bar\u03bd$ transition: $V_{ub}$ is the smallest and least known of all CKM matrix elements; the\ncommunity currently determines its magnitude primarily through the exclusive\nprocess $B\\to\\pi\\ell\\bar{\\nu}$. Here we present our progress toward a lattice\nQCD determination of the $V_{ub}$ matrix element from a novel transition --\n$B\\to\\pi\\pi\\ell\\bar{\\nu}$ process, where the $\\pi\\pi$ system is in a $P$ wave\nand scattering features the $\\rho(770)$ resonance as an enhancement. We perform\nour calculation on $N_f=2+1$ isotropic clover fermions on a lattice of\n$L\\approx 3.6$ fm and a pion mass of $\\approx 320$ MeV; for the $b$-quark we\nuse the anisotropic clover action. After a brief overview of the theoretical\nframework, we will discuss some preliminary results."
    },
    {
        "anchor": "Equation of state of QCD at finite chemical potential from an\n  alternative expansion scheme: The equation of state of Quantum Chromodynamics (QCD) at finite density is\ncurrently known only in a limited range in the baryon chemical potential\n$\\mu_B$. This is due to fundamental shortcomings of traditional methods such as\nTaylor expansion around $\\mu_B=0$. In this contribution, we present an\nalternative scheme that displays substantially improved convergence over the\nTaylor expansion method. We calculate the alternative expansion coefficients in\nthe continuum, and show our results for the thermodynamic observables up to\n$\\mu_B/T\\le3.5$.",
        "positive": "Comparison of 4d and 3d Lattice Results for the Electroweak Phase\n  Transition: We compare 4d lattice results for the finite temperature phase transition in\nthe SU(2)+Higgs model with 3d lattice results for the phase transition in the\ncorresponding dimensionally reduced effective theory. While the large errorbars\nand the lack of a relation of the 4d lattice gauge coupling to continuum\nphysics prevent rigorous conclusions, the results are nevertheless compatible.\nThis provides a direct non-perturbative check of dimensional reduction in the\npresent context."
    },
    {
        "anchor": "Nonrelativistic lattice study of stoponium: We calculate the bound state properties of stoponium using lattice\nformulation of nonrelativistic effective field theory for stop which is moving\nnonrelativistically in the rest frame of stoponium. Our calculation method is\nsimilar to that employed in lattice nonrelativistic quantum chromodynamics\n(NRQCD) studies for charmonium and bottominum. Using $16^3 \\times 256$ quenched\nlattice gauge field configurations at $a^{-1} = 50(1) {\\rm GeV}$, we obtain the\nstopoinium mass and the lattice matrix element which is related to the\nwavefunction at the origin for the $1S$ state and find that the lattice\n$|R_{1S} (0)|^2/M_{1S}^3$ is $3.5 \\sim 4$ larger than that from a potential\nmodel calculation for $200 {\\rm GeV} \\le M_{1S} \\le 800 {\\rm GeV}$.",
        "positive": "Excited meson radiative transitions from lattice QCD using variationally\n  optimized operators: We explore the use of optimized operators, designed to interpolate only a\nsingle meson eigenstate, in three-point correlation functions with a\nvector-current insertion. These operators are constructed as linear\ncombinations in a large basis of meson interpolating fields using a variational\nanalysis of matrices of two-point correlation functions. After performing such\na determination at both zero and non-zero momentum, we compute three-point\nfunctions and are able to study radiative transition matrix elements featuring\nexcited state mesons. The required two- and three-point correlation functions\nare efficiently computed using the distillation framework in which there is a\nfactorization between quark propagation and operator construction, allowing for\na large number of meson operators of definite momentum to be considered. We\nillustrate the method with a calculation using anisotopic lattices having three\nflavors of dynamical quark all tuned to the physical strange quark mass,\nconsidering form-factors and transitions of pseudoscalar and vector meson\nexcitations. The dependence on photon virtuality for a number of form-factors\nand transitions is extracted and some discussion of excited-state phenomenology\nis presented."
    },
    {
        "anchor": "A precise determination of the psibar-psi anomalous dimension in\n  conformal gauge theories: A strategy for computing the psibar-psi anomalous dimension at the fixed\npoint in infrared-conformal gauge theories from lattice simulations is\ndiscussed. The method is based on the scaling of the spectral density of the\nDirac operator or rather its integral, the mode number. It is relatively cheap,\nmainly for two reasons: (a) the mode number can be determined with quite high\naccuracy, (b) the psibar-psi anomalous dimension is extracted from a fit of\nseveral observables on the same set of configurations (no scaling in the\nLagrangian parameters is needed). As an example the psibar-psi anomalous\ndimension has been computed in the SU(2) theory with 2 Dirac fermions in the\nadjoint representation of the gauge group, and has been found to be 0.371(20).\nIn this particular case, the proposed strategy has proved to be very robust and\neffective.",
        "positive": "Pion Decay Constant, $Z_A$ and Chiral Log from Overlap Fermions: We report our calculation of the pion decay constant $f_\\pi$, the axial\nrenormalization constant $Z_A$, and the quenched chiral logarithms from the\noverlap fermions. The calculation is done on a quenched $20^4$ lattice at\n$a=0.148$ fm using tree level tadpole improved gauge action. The smallest pion\nmass we reach is about 280 MeV. The lattice size is about 4 times the Compton\nwavelength of the lowest mass pion."
    },
    {
        "anchor": "Scalar Quarkonium Masses: We evaluate the valence approximation to the mass of scalar quarkonium for a\nrange of different parameters. Our results strongly suggest that the infinite\nvolume continuum limit of the mass of $s\\overline{s}$ scalar quarkonium lies\nwell below the mass of $f_J(1710)$. The resonance $f_0(1500)$ appears to the\nbest candidate for $s\\overline{s}$ scalar quarkonium.",
        "positive": "Topological susceptibility and string tension in the lattice CP(N)\n  models: In the lattice CP(N) models we studied the problems related to the measure of\nthe topological susceptibility and the string tension . We perfomed numerical\nsimulations at N=4 and N=10. In order to test the universality, we adopted two\ndifferent lattice formulations. Scaling and universality tests led to the\nconclusion that at N=10 the geometrical approach gives a good definition of\nlattice topological susceptibility. On the other hand, N=4 proved not to be\nlarge enough to suppress the unphysical configurations, called dislocations,\ncontributing to the topological susceptibility. We obtained other\ndeterminations of the topological susceptibility by the field theoretical\nmethod, wich relies on a local definition of the lattice topological charge\ndensity, and the cooling method. They gave quite consistent results, showing\nscaling and universality. The large-N expansion predicts an exponential area\nlaw behavior for sufficiently large Wilson loops, which implies confinement,\ndue to the dynamical matter fields and absence of the screening phenomenon. We\ndetermined the string tension, without finding evidence of screening effects."
    },
    {
        "anchor": "The Status of Lattice Calculations of the Nucleon Structure Functions: We review our progress on the lattice calculation of low moments of both the\nunpolarised and polarised nucleon structure functions.",
        "positive": "Bosonization and the lattice: the $d=2$ Gross-Neveu model: We consider the lattice formulation of bosonized quantum field theories. As a\nnon trivial example, we study the two dimensional Gross-Neveu model. Analytical\ninvestigations and direct numerical simulation strongly suggest that the\nlattice model reproduces the continuum physics. Anticommuting fields are not\nrequired and there are not related doubling problems. (3 PostScript figures\navailable from the author)"
    },
    {
        "anchor": "An Efficient Algorithm for QCD with Light Dynamical Quarks: A new approach to the inclusion of virtual quark effects in lattice QCD\nsimulations is presented. Infrared modes which build in the chiral physics in\nthe light quark mass limit are included exactly and in a gauge invariant way.\nAt fixed physical volume the number of relevant infrared modes does not\nincrease as the continuum limit is approached. The acceptance of our procedure\ndoes not decrease substantially in the limit of small quark masses. Two\nalternative approaches are discussed for including systematically the remaining\nultraviolet modes. In particular, we present evidence that these modes are\naccurately described by an effective action involving only small Wilson loops.",
        "positive": "Gluinos on the lattice: quenched calculations: As a preparation for the numerical study of the SU(2) gauge theory with\ngluinos, the spectral properties of the fermion matrix and the masses of\npseudoscalar and scalar states are investigated in the quenched approximation.\nThe behaviour of the disconnected fermion diagrams on small lattices is also\nstudied."
    },
    {
        "anchor": "End Point of a First-Order Phase Transition in Many-Flavor Lattice QCD\n  at Finite Temperature and Density: Towards the feasibility study of the electroweak baryogenesis in realistic\ntechnicolor scenario, we investigate the phase structure of (2+Nf)-flavor QCD,\nwhere the mass of two flavors is fixed to a small value and the others are\nheavy. For the baryogenesis, an appearance of a first order phase transition at\nfinite temperature is a necessary condition. Using a set of configurations of\ntwo-flavor lattice QCD and applying the reweighting method, the effective\npotential defined by the probability distribution function of the plaquette is\ncalculated in the presence of additional many heavy flavors. Through the shape\nof the effective potential, we determine the critical mass of heavy flavors\nseparating the first order and crossover regions and find it to become larger\nwith Nf. We moreover study the critical line at finite density and the first\norder region is found to become wider as increasing the chemical potential.\nPossible applications to real (2+1)-flavor QCD are discussed.",
        "positive": "Perturbative Corrections for Staggered Four-Fermion Operators: We present results for one-loop matching coefficients between continuum\nfour-fermion operators, defined in the Naive Dimensional Regularization scheme,\nand staggered fermion operators of various types. We calculate diagrams\ninvolving gluon exchange between quark lines, and ``penguin'' diagrams\ncontaining quark loops. For the former we use Landau gauge operators, with and\nwithout $O(a)$ improvement, and including the tadpole improvement suggested by\nLepage and Mackenzie.For the latter we use gauge-invariant operators. Combined\nwith existing results for two-loop anomalous dimension matrices and one-loop\nmatching coefficients, our results allow a lattice calculation of the\namplitudes for $K\\bar K$ mixing and $K\\to\\pi\\pi$ decays with all corrections of\n$O(g^2)$ included. We also discuss the mixing of $\\Delta S=1$ operators with\nlower dimension operators, and show that, with staggered fermions, only a\nsingle lower dimension operator need be removed by non-perturbative\nsubtraction."
    },
    {
        "anchor": "Glueball Mass Predictions of the Valence Approximation to Lattice QCD: We evaluate the infinite volume, continuum limit of glueball masses in the\nvalence (quenched) approximation to lattice QCD. For the lightest scalar and\ntensor states we obtain masses of $1648 \\pm 58$ MeV and $2267 \\pm 104$ MeV,\nrespectively.",
        "positive": "A gauge invariant study of the monopole condensation in non Abelian\n  lattice gauge theories: We investigate the Abelian monopole condensation in finite temperature SU(2)\nand SU(3) pure lattice gauge theories. To this end we introduce a gauge\ninvariant disorder parameter built up in terms of the lattice Schr\\\"odinger\nfunctional. Our numerical results show that the disorder parameter is different\nfrom zero and Abelian monopole condense in the confined phase. On the other\nhand our numerical data suggest that the disorder parameter tends to zero, in\nthe thermodynamic limit, when the gauge coupling constant approaches the\ncritical deconfinement value. In the case of SU(3) we also compare the\ndifferent kinds of Abelian monopoles which can be defined according to the\nchoice of the Abelian subgroups."
    },
    {
        "anchor": "Simulation of supersymmetric models on the lattice without a sign\n  problem: Simulations of supersymmetric models on the lattice with (spontaneously)\nbroken supersymmetry suffer from a fermion sign problem related to the\nvanishing of the Witten index. We propose a novel approach which solves this\nproblem in low dimensions by formulating the path integral on the lattice in\nterms of fermion loops. The formulation is based on the exact hopping expansion\nof the fermionic action and allows the explicit decomposition of the partition\nfunction into bosonic and fermionic contributions. We devise a simulation\nalgorithm which separately samples the fermionic and bosonic sectors, as well\nas the relative probabilities between them. The latter then allows a direct\ncalculation of the Witten index and the corresponding Goldstino mode. Finally,\nwe present results from simulations on the lattice for the spectrum and the\nWitten index for N=2 supersymmetric quantum mechanics.",
        "positive": "Multigrid solver for clover fermions: We present an adaptive multigrid Dirac solver developed for Wilson clover\nfermions which offers order-of-magnitude reductions in solution time compared\nto conventional Krylov solvers. The solver incorporates even-odd\npreconditioning and mixed precision to solve the Dirac equation to double\nprecision accuracy and shows only a mild increase in time to solution for\ndecreasing quark mass. We show actual time to solution on production lattices\nin comparison to conventional Krylov solvers and will also discuss the setup\nprocess and its relative cost to the total solution time."
    },
    {
        "anchor": "Fermion bag solutions to some sign problems in four-fermion field\n  theories: Lattice four-fermion models containing $N$ flavors of staggered fermions,\nthat are invariant under $Z_2$ and U(1) chiral symmetries, are known to suffer\nfrom sign problems when formulated using the auxiliary field approach. Although\nthese problems have been ignored in previous studies, they can be severe. In\nthis talk, we show that the sign problems disappear when the models are\nformulated in the fermion bag approach, allowing us to solve them rigorously\nfor the first time.",
        "positive": "Nucleon-pion-state contributions in the determination of the nucleon\n  axial charge: The nucleon-pion-state contributions to QCD 2- and 3-point functions used in\nthe calculation of the nucleon axial charge are studied in chiral perturbation\ntheory. For sufficiently small quark masses and large volumes the nucleon-pion\nstates are expected to have smaller total energy than the single-particle\nexcited states. To leading order in chiral perturbation theory the results do\nnot depend on low-energy constants associated with the interpolating nucleon\nfields and apply to local as well as smeared interpolators. The\nnucleon-pion-state contribution is found to be at the few percent level."
    },
    {
        "anchor": "Decay amplitudes to three hadrons from finite-volume matrix elements: We derive relations between finite-volume matrix elements and infinite-volume\ndecay amplitudes, for processes with three spinless, degenerate and either\nidentical or non-identical particles in the final state. This generalizes the\nLellouch-L\\\"uscher relation for two-particle decays and provides a strategy for\nextracting three-hadron decay amplitudes using lattice QCD. Unlike for two\nparticles, even in the simplest approximation, one must solve integral\nequations to obtain the physical decay amplitude, a consequence of the\nnontrivial finite-state interactions. We first derive the result in a\nsimplified theory with three identical particles, and then present the\ngeneralizations needed to study phenomenologically relevant three-pion decays.\nThe specific processes we discuss are the CP-violating $K \\to 3\\pi$ weak decay,\nthe isospin-breaking $\\eta \\to 3\\pi$ QCD transition, and the electromagnetic\n$\\gamma^*\\to 3\\pi$ amplitudes that enter the calculation of the hadronic vacuum\npolarization contribution to muonic $g-2$.",
        "positive": "Zero-modes of the QED Neuberger Dirac operator: We consider $4d$ compact lattice QED in the quenched approximation. First, we\nbriefly summarize the spectrum of the staggered Dirac operator and its\nconnection with random matrix theory. Afterwards we present results for the\nlow-lying eigenmodes of the Neuberger overlap-Dirac operator. In the strong\ncoupling phase we find exact zero-modes. Subsequently we discuss possibly\nrelated topological excitations of the U(1) lattice gauge theory."
    },
    {
        "anchor": "2+1 Flavor Domain Wall Fermion QCD Lattices: Ensemble Production and\n  (some) Properties: The RBC and UKQCD Collaborations continue to produce 2+1 flavor domain wall\nfermion ensembles, currently focusing on an ensemble with a $96^3 \\times 192$\nvolume on SUMMIT at ORNL with $1/a \\approx 2.8$ GeV, and smaller ensembles at\nstronger couplings. The $1/a \\approx 2.8$ GeV ensemble uses the Exact One\nFlavor Algorithm for the strange quark, along with the Multisplitting\nPreconditioned Conjugate Gradient for solving the Dirac equation. We report on\nour progress and experience to date with the evolution of this ensemble.",
        "positive": "Scalar and Tensor Glueballs on Asymmetric Coarse Lattices: Scalar and tensor glueball spectrum is studied using an improved gluonic\naction on asymmetric lattices in the pure SU(3) gauge theory. The smallest\nspatial lattice spacing is about 0.08fm which makes the extrapolation to the\ncontinuum limit more reliable. In particular, attention is paid to the scalar\nglueball mass which is known to have problems in the extrapolation. Converting\nour lattice results to physical units using the scale set by the static quark\npotential, we obtain the following results for the glueball masses:\n$M_G(0^{++})=1730(90)MeV$ for the scalar glueball mass and\n$M_G(2^{++})=2400(95)MeV$ for the tensor glueball."
    },
    {
        "anchor": "Strongly coupled N=1 SYM theory on the lattice: We propose a strong coupling expansion as a possible tool to obtain\nqualitative and quantitative informations about N=1 SYM theory. We point out\nthe existence of a mapping between strongly coupled lattice N=1 SYM theory and\na generalized SO(4) antiferromagnetic spin system.",
        "positive": "Status of the APENet project: We present the current status of APENet, our custom 3-dimensional\ninterconnect architecture for PC clusters environment. We report some\nmicro-benchmarks on our recent large installation as well as new developments\non the software and hardware side. The low level device driver has been\nreworked by following a custom hardware RDMA architecture, and MPICH-VMI, an\nimplementation of the MPI library, has been ported to APENet."
    },
    {
        "anchor": "Bloch Waves in Minimal Landau Gauge and the Infinite-Volume Limit of\n  Lattice Gauge Theory: By exploiting the similarity between Bloch's theorem for electrons in\ncrystalline solids and the problem of Landau gauge-fixing in Yang-Mills theory\non a \"replicated\" lattice, one is able to obtain essentially infinite-volume\nresults from numerical simulations performed on a relatively small lattice.\nThis approach, proposed by D. Zwanziger in \\cite{Zwanziger:1993dh}, corresponds\nto taking the infinite-volume limit for Landau-gauge field configurations in\ntwo steps: firstly for the gauge transformation alone, while keeping the\nlattice volume finite, and secondly for the gauge-field configuration itself.\nThe solutions to the gauge-fixing condition are then given in terms of Bloch\nwaves. Applying the method to data from Monte Carlo simulations of pure SU(2)\ngauge theory in two and three space-time dimensions, we are able to evaluate\nthe Landau-gauge gluon propagator for lattices of linear extent up to sixteen\ntimes larger than that of the simulated lattice. The approach is reminiscent of\nFisher and Ruelle's construction of the thermodynamic limit in classical\nstatistical mechanics.",
        "positive": "Symmetries and Interactions from Lattice QCD: Precision experimental tests of the Standard Model of particle physics (SM)\nare one of our best hopes for discovering what new physics lies beyond the SM\n(BSM). Key in the search for new physics is the connection between theory and\nexperiment. Forging this connection for searches involving low-energy hadronic\nor nuclear environments requires the use of a non-perturbative theoretical\ntool, lattice QCD. We present two recent lattice QCD calculations by the CalLat\ncollaboration relevant for new physics searches: the nucleon axial coupling,\n$g_A$, whose precise value as predicted by the SM could help point to new\nphysics contributions to the so-called \"neutron lifetime puzzle\", and hadronic\nmatrix elements of short-ranged operators relevant for neutrinoless double beta\ndecay searches."
    },
    {
        "anchor": "Nucleon generalized form factors from lattice QCD with nearly physical\n  quark masses: We determine generalized form factors of the nucleon from lattice simulations\nwith $N_f = 2$ mass-degenerate non-perturbatively improved\nWilson-Sheikholeslami-Wohlert fermions down to a pion mass of 150 MeV. We also\npresent the resulting isovector quark angular momentum. Possible excited-state\ncontaminations are investigated with correlated simultaneous fits.",
        "positive": "Probing TeV scale physics in precision UCN decays: We present the calculation of matrix elements of iso-vector scalar, axial and\ntensor charges between a neutron and a proton state on dynamical $N_f=2+1+1$\nHISQ configurations generated by the MILC Collaboration using valence clover\nfermions. These matrix elements are needed to probe novel scalar and tensor\ninteractions in neutron beta-decay that can arise in extensions to the Standard\nModel at the TeV scale. Results are presented at one value of the lattice\nspacing, $a=0.12$ fm, and two values of light quarks corresponding to\n$M_\\pi=310$ and $220$ MeV. We discuss two sources of systematic errors,\ncontribution of excited states to these matrix elements and the renormalization\nconstants, and the efficacy of methods used to control them."
    },
    {
        "anchor": "Pion form factors from two-flavor lattice QCD with exact chiral symmetry: We calculate pion vector and scalar form factors in two-flavor lattice QCD\nand study the chiral behavior of the vector and scalar radii <r^2>_{V,S}.\nNumerical simulations are carried out on a 16^3 x 32 lattice at a lattice\nspacing of 0.12 fm with quark masses down to \\sim m_s/6, where m_s is the\nphysical strange quark mass. Chiral symmetry, which is essential for a direct\ncomparison with chiral perturbation theory (ChPT), is exactly preserved in our\ncalculation at finite lattice spacing by employing the overlap quark action. We\nutilize the so-called all-to-all quark propagator in order to calculate the\nscalar form factor including the contributions of disconnected diagrams and to\nimprove statistical accuracy of the form factors. A detailed comparison with\nChPT reveals that the next-to-next-to-leading-order contributions to the radii\nare essential to describe their chiral behavior in the region of quark mass\nfrom m_s/6 to m_s/2. Chiral extrapolation based on two-loop ChPT yields\n<r^2>_V=0.409(23)(37)fm and <r^2>_S=0.617(79)(66)fm, which are consistent with\nphenomenological analysis. We also present our estimates of relevant low-energy\nconstants.",
        "positive": "Relativistic corrections to the static potential from generalized Wilson\n  loops at finite flow time: We present results from an ongoing project concerned with the computation of\n$\\mathcal{O}(1/m_Q)$ and $\\mathcal{O}(1/m_Q^2)$ relativistic corrections to the\nstatic potential. These corrections are extracted from Wilson loops with two\nchromo-field insertions. We use gradient flow, which allows to renormalize the\ninserted fields and leads to a significantly improved signal-to-noise ratio,\nproviding access to loops with large spatial and temporal extents."
    },
    {
        "anchor": "Phase structure of electroweak vacuum in a strong magnetic field: the\n  lattice results: Using first-principle lattice simulations, we demonstrate that in the\nbackground of a strong magnetic field (around $10^{20}$ T), the electroweak\nsector of the vacuum experiences two consecutive crossover transitions\nassociated with dramatic changes in the zero-temperature dynamics of the vector\n$W$ bosons and the scalar Higgs particles, respectively. Above the first\ncrossover, we observe the appearance of large, inhomogeneous structures\nconsistent with a classical picture of the formation of $W$ and $Z$ condensates\npierced by vortices. The presence of the $W$ and $Z$ condensates supports the\nemergence of the exotic superconducting and superfluid properties induced by a\nstrong magnetic field in the vacuum. We find evidence that the vortices form a\ndisordered solid or a liquid rather than a crystal. The second transition\nrestores the electroweak symmetry. Such conditions can be realized in the\nnear-horizon region of the magnetized black holes.",
        "positive": "Lambda Phenomena: the Lambda points of liquid Helium and chiral QCD: The superfluid transition of liquid Helium shares an interesting phenomenon\nwith the chiral limit of QCD: the specific heat is finite at the critical\npoint, but has a cusp. From this follows an interesting mixture of universal\nand non-universal features at the critical point. Through the CP symmetry of\nchiral QCD, this has implications for the fourth order baryon number\nsusceptibility and susceptibilities of higher orders. Investigations of such a\nscaling will show us whether O(4) scaling is an accurate description of\nbaryon-free QCD when the pion mass is realistic."
    },
    {
        "anchor": "Some physics of the two-dimensional $\\mathcal{N}=(2,2)$ supersymmetric\n  Yang-Mills theory: Lattice Monte Carlo study: We illustrate some physical application of a lattice formulation of the\ntwo-dimensional $\\mathcal{N}=(2,2)$ supersymmetric SU(2) Yang-Mills theory with\na (small) supersymmetry breaking scalar mass. Two aspects, power-like behavior\nof certain correlation functions (which implies the absence of the mass gap)\nand the static potential $V(R)$ between probe charges in the fundamental\nrepresentation, are considered. For the latter, for $R\\lesssim1/g$, we observe\na linear confining potential with a finite string tension. This confining\nbehavior appears distinct from a theoretical conjecture that a probe charge in\nthe fundamental representation is screened in two-dimensional gauge theory with\nan adjoint massless fermion, although the static potential for $R\\gtrsim1/g$\nhas to be systematically explored to conclude real asymptotic behavior in large\ndistance.",
        "positive": "Renormalization factor of four fermi operators with clover fermion and\n  Iwasaki gauge action: Renormalization factors of four-quark operators are perturbatively calculated\nfor the improved Wilson fermion with clover term and the Iwasaki gauge action.\nA main application shall be the $K\\to\\pi\\pi$ decay amplitude and the\ncalculation is restricted to the parity odd operator, for which the operators\nare multiplicatively renormalizable without mixing with wrong operators that\nhave different chiral structures."
    },
    {
        "anchor": "Lattice QCD in curved spacetimes: We formulate the lattice QCD simulation with background classical\ngravitational fields. This formulation enables us to study nonperturbative\naspects of quantum phenomena in curved spacetimes from the first principles. As\nthe first application, we perform the simulation with the\nFriedmann-Lemaitre-Robertson-Walker metric and analyze particle production in\nthe expanding universe.",
        "positive": "Lattice QCD with two dynamical flavors of domain wall quarks: We present results from the first large-scale study of two flavor QCD using\ndomain wall fermions (DWF), a chirally symmetric fermion formulation which has\nproven to be very effective in the quenched approximation. We work on lattices\nof size 16^3x32, with a lattice cut-off of a^{-1}\\approx 1.7 GeV, and dynamical\n(or sea) quark masses in the range m_{strange}/2 \\simle m_{sea} \\simle\nm_{strange}. After discussing the algorithmic and implementation issues\ninvolved in simulating dynamical DWF, we report on the low-lying hadron\nspectrum, decay constants, static quark potential, and the important kaon weak\nmatrix element describing indirect CP violation in the Standard Model, B_K. In\nthe latter case we include the effect of non-degenerate quark masses (m_s \\neq\nm_u = m_d), finding B_K(MS-bar, 2 GeV) = 0.495(18)."
    },
    {
        "anchor": "Dual Higgs Theory for Color Confinement: We study theoretical bases of the dual Higgs theory for confinement physics\nin QCD in terms of monopoles and the gluon configuration in the maximally\nabelian (MA) gauge. Abelian dominance for the confinement force can be\nanalytically proved by regarding the off-diagonal angle variable as a random\nvariable in the lattice formalism. In the long-distance scale, the contribution\nof off-diagonal gluons to the Wilson loop cancels each other and exhibits a\nperimeter law behavior, which leads to exact abelian dominance on the string\ntension if the finite size effect of the Wilson loop is removed. We investigate\nthe appearance of the monopole in the QCD vacuum, considering the role of\noff-diagonal gluons. The monopole carries a large fluctuation of the gluon\nfield and provides a large abelian action in abelian projected QCD. Due to the\npartial cancellation between the abelian part and the off-diagonal part of the\nQCD action, the monopole can appear in QCD without large cost of the QCD\naction. The off-diagonal gluon is necessary for existence of the monopole at\nthe short-distance scale. We study monopole condensation, which is the\nrequirement of the dual Higgs theory, by comparing the QCD vacuum with the\nmonopole-current system. We find that ``entropy'' of monopole-current dominates\nthan its ``energy'', and the monopole seems to be condensed at the infrared\nscale in the QCD vacuum.",
        "positive": "Preliminary QCD phase transition line for 695 MeV dynamical staggered\n  fermions from effective Polyakov line actions: We present a phase diagram for SU(3) lattice gauge theory with 695 MeV\ndynamical staggered fermions, in the plane of temperature and chemical\npotential, obtained from effective Polyakov line actions. The derivation is via\nthe method of relative weights, and the effective theories are solved at finite\nchemical potential by mean field theory."
    },
    {
        "anchor": "Pions in Lattice QCD with the Overlap Fermions at Strong Gauge Coupling: In the previous paper we developed a strong-coupling expansion for the\nlattice QCD with the overlap fermions and showed that L\\\"usher's \"extended\"\nchiral symmetry is spontaneously broken in some parameter region of the overlap\nfermions. In this paper, we obtain a low-energy effective action and show that\nthere exist quasi-Nambu-Goldsone bosons which are identified as the pions. The\npion field is a {\\em nonlocal} composite field of quark and anti-quark even at\nthe strong-coupling limit because of the nonlocality of the overlap fermion\nformalism and L\\\"usher's chiral symmetry. The pions become massless in the\nlimit of the vanishing bare-quark mass as it is desired.",
        "positive": "Eigenvalue spectrum and scaling dimension of lattice $\\mathcal{N} = 4$\n  supersymmetric Yang-Mills: We investigate the lattice regularization of $\\mathcal{N} = 4$ supersymmetric\nYang-Mills theory, by stochastically computing the eigenvalue mode number of\nthe fermion operator. This provides important insight into the non-perturbative\nrenormalization group flow of the lattice theory, through the definition of a\nscale-dependent effective mass anomalous dimension. While this anomalous\ndimension is expected to vanish in the conformal continuum theory, the finite\nlattice volume and lattice spacing generically lead to non-zero values, which\nwe use to study the approach to the continuum limit. Our numerical results,\ncomparing multiple lattice volumes, 't Hooft couplings, and numbers of colors,\nconfirm convergence towards the expected continuum result, while quantifying\nthe increasing significance of lattice artifacts at larger couplings."
    },
    {
        "anchor": "Which Chiral Symmetry is Restored in High Temperature QCD?: Sigma models for the high temperature phase transition in quantum\nchromodynamics (QCD) suggest that at high temperature the SU(N_f) x SU(N_f)\nchiral symmetry becomes exact, but the anomalous axial U(1) symmetry need not\nbe restored. In numerical lattice simulations, traditional methods for\ndetecting symmetry restoration have sought multiplets in the screening mass\nspectrum. However, these methods were imprecise and the results, so far,\nincomplete. With improved statistics and methodology, we are now able to offer\nevidence for a restoration of the SU(2) x SU(2) chiral symmetry just above the\ncrossover, but not of the axial U(1) chiral symmetry.",
        "positive": "Exploring the infrared Landau gauge propagators using large asymmetric\n  lattices: We report on the infrared limit of the quenched lattice Landau gauge gluon\nand ghost propagators computed from large asymmetric lattices. In particular,\nthe compatibility of the pure power law infrared solutions of the\nDyson-Schwinger equations with the lattice data is investigated and the\nexponent $\\kappa$ is measured. The gluon lattice data favour $\\kappa \\sim\n0.52$, which would imply a vanishing zero momentum gluon propagator. For the\nsubset of lattices where the ghost propagator was computed, the data is not\ncompatible with a pure power law. Our data also show a decreasing running\ncoupling in the infrared region. Furthermore, positivity violation for the\ngluon propagator is also verified."
    },
    {
        "anchor": "The critical end point in QCD: In this talk I present the logic behind, and examine the reliability of,\nestimates of the critical end point (CEP) of QCD using the Taylor expansion\nmethod.",
        "positive": "Chern-Simons theory on the lattice: We present new proposals for the representation of a Chern-Simons term on the\nlattice. In the first part, such a term is constructed from the fermion\ndeterminant, and in the second part directly from the Abelian gauge term. In\nboth cases, the parity transformation is modified on the lattice without\naffecting its continuum limit."
    },
    {
        "anchor": "Gauge invariant input to neural network for path optimization method: We investigate the efficiency of a gauge invariant input to a neural network\nfor the path optimization method. While the path optimization with a completely\ngauge-fixed link-variable input has successfully tamed the sign problem in a\nsimple gauge theory, the optimization does not work well when the gauge degrees\nof freedom remain. We propose to employ a gauge invariant input, such as\nplaquette, to overcome this problem. The efficiency of the gauge invariant\ninput to the neural network is evaluated for the 2-dimensional $U(1)$ gauge\ntheory with a complex coupling. The average phase factor is significantly\nenhanced by the path optimization with the plaquette input, indicating good\ncontrol of the sign problem. It opens a possibility that the path optimization\nis available to complicated gauge theories, including Quantum Chromodynamics,\nin a realistic setup.",
        "positive": "Numerical Stability of Lanczos Methods: The Lanczos algorithm for matrix tridiagonalisation suffers from strong\nnumerical instability in finite precision arithmetic when applied to evaluate\nmatrix eigenvalues. The mechanism by which this instability arises is well\ndocumented in the literature. A recent application of the Lanczos algorithm\nproposed by Bai, Fahey and Golub allows quadrature evaluation of inner products\nof the form $\\psi^\\dagger g(A) \\psi$. We show that this quadrature evaluation\nis numerically stable and explain how the numerical errors which are such a\nfundamental element of the finite precision Lanczos tridiagonalisation\nprocedure are automatically and exactly compensated in the Bai, Fahey and Golub\nalgorithm. In the process, we shed new light on the mechanism by which roundoff\nerror corrupts the Lanczos procedure"
    },
    {
        "anchor": "EoS of finite density QCD with Wilson fermions by Multi-Parameter\n  Reweighting and Taylor expansion: The equation of state (EoS), quark number density and susceptibility at\nnonzero quark chemical potential $\\mu$ are studied in lattice QCD simulations\nwith a clover-improved Wilson fermion of 2-flavors and RG-improved gauge\naction. To access nonzero $\\mu$, we employ two methods : a multi-parameter\nreweighting (MPR) in $\\mu$ and $\\beta$ and Taylor expansion in $\\mu/T$. The use\nof a reduction formula for the Wilson fermion determinant enables to study the\nreweighting factor in MPR explicitly and heigher-order coefficients in Taylor\nexpansion free from errors of noise method, although calculations are limited\nto small lattice size. As a consequence, we can study the reliability of the\nthermodynamical quantities through the consistency of the two methods, each of\nwhich has different origin of the application limit.\n  The thermodynamical quantities are obtained from simulations on a $8^3\\times\n4$ lattice with an intermediate quark mass($m_{\\rm PS}/m_{\\rm V}=0.8)$. The MPR\nand Taylor expansion are consistent for the EoS and number density up to\n$\\mu/T\\sim 0.8$ and for the number susceptibility up to $\\mu/T \\sim 0.6$. This\nimplies within a given statistics that the overlap problem for the MPR and\ntruncation error for the Taylor expansion method are negligible in these\nregions.\n  In order to make MPR methods work, the fluctuation of the reweighting factor\nshould be small. We derive the equation of the reweighting line where the\nfluctuation is small, and show that the equation of the reweighting line is\nconsistent with the fluctuation minimum condition.",
        "positive": "Correlated Dirac Eigenvalues and Axial Anomaly in Chiral Symmetric QCD: We introduce novel relations between the derivatives\n[$\\partial^{n}\\rho(\\lambda, m_{l})/\\partial m_{l}^n$] of the Dirac eigenvalue\nspectrum [$\\rho(\\lambda, m_{l})$] with respect to the light sea quark mass\n($m_{l}$) and the $(n+1)$-point correlations among the eigenvalues ($\\lambda$)\nof the massless Dirac operator. Using these relations we present lattice QCD\nresults for $\\partial^{n}\\rho(\\lambda, m_{l})/\\partial m_{l}^n$ ($n=1, 2, 3$)\nfor $m_{l}$ corresponding to pion masses $m_\\pi=160-55$ MeV, and at a\ntemperature of about 1.6 times the chiral phase transition temperature.\nCalculations were carried out using (2+1) flavors of highly improved staggered\nquarks with the physical value of strange quark mass, three lattice spacings\n$a=0.12, 0.08, 0.06$ fm, and lattices having aspect ratios $4-9$. We find that\n$\\rho(\\lambda\\to0, m_{l})$ develops a peaked structure. This peaked structure\narises due to non-Poisson correlations within the infrared part of the Dirac\neigenvalue spectrum, becomes sharper as $a\\to0$, and its amplitude is\nproportional to $m_{l}^2$. We demonstrate that this $\\rho(\\lambda\\to0,m_l)$ is\nresponsible for the manifestations of axial anomaly in two-point correlation\nfunctions of light scalar and pseudoscalar mesons. After continuum and chiral\nextrapolations we find that axial anomaly remains manifested in two-point\ncorrelation functions of scalar and pseudoscalar mesons in the chiral limit."
    },
    {
        "anchor": "Nature of the Roberge-Weiss transition end points in two-flavor lattice\n  QCD with Wilson quarks: We make simulations with 2 flavor Wilson fermions to investigate the nature\nof the end points of Roberge-Weiss (RW) first order phase transition lines. The\nsimulations are carried out at 9 values of the hopping parameter $\\kappa$\nranging from 0.155 to 0.198 on different lattice spatial volume. The Binder\ncumulants, susceptibilities and reweighted distributions of the imaginary part\nof Polyakov loop are employed to determine the nature of the end points of RW\ntransition lines. The simulations show that the RW end points are of first\norder at the values of $\\kappa$ in our simulations.",
        "positive": "The Charmonium Potential at Non-Zero Temperature: The potential between charm and anti-charm quarks is calculated\nnon-perturbatively using physical, rather than static quarks at temperatures on\nboth sides of the deconfinement transition $T_{\\rm C}$, using a lattice\nsimulation with 2+1 dynamical quark flavours. We used the HAL QCD\ntime-dependent method, originally developed for inter-nucleon potentials. Our\nlattices are anisotropic, with temporal lattice spacing less than the spatial\none which enhances the information content of our correlators at each\ntemperature. Local-extended charmonium correlators were calculated efficiently\nby contracting propagators in momentum rather than coordinate space. We find no\nsignificant variation in the central potential for temperatures in the confined\nphase. As the temperature increases into the deconfinement phase, the potential\nflattens, consistent with the expected weakening interaction. We fit the\npotential to both the (a) Cornell and (b) Debye-screened potential forms, with\nthe latter better reproducing the data. The zero temperature string tension\nobtained from (a) agrees with results obtained elsewhere, and it decreases with\ntemperature, but at a slower rate than from the static quark approximation. The\nDebye mass from (b) is close to zero for small temperatures, but starts to\nincrease rapidly around $T_{\\rm C}$. The spin-dependent potential is found to\nhave a repulsive core and a distinct temperature dependence above $T_{\\rm C}$\nat distances $\\sim 1$ fm."
    },
    {
        "anchor": "$q\\bar q$-potential: a critical reappraisal: We show how it is possible to define and compute the potential between $q$\nand $\\bar q$ external sources in the singlet and octet (adjoint) representation\nof the colour group.",
        "positive": "Heavy Baryon Spectroscopy: We present the preliminary results of an exploratory study of heavy baryon\nspectroscopy, using the $O(a)$-improved fermionic action. Estimates of masses\nand splittings at the charm and beauty physical limit are reported."
    },
    {
        "anchor": "Effective Constraint Potential for Abelian Monopole in SU(2) Lattice\n  Gauge Theory: We describe numerical calculation results for the probability distribution of\nthe value of the monopole creation operator in the SU(2) lattice gluodynamics.\nWe work in the maximal abelian projection. It occurs that at low temperatures,\nbelow the deconfinement phase transition, the maximum of the distribution is\nshifted from zero, which means that the effective constraint potential is of\nthe Higgs type. Above the phase transition the minimum of the potential (the\nmaximum of the monopole field distribution) is at the zero value of the\nmonopole field. This fact confirms the existence of the abelian monopole\ncondensate in the confinement phase of lattice gluodynamics, and agrees with\nthe dual superconductor model of the confining vacuum.",
        "positive": "Composite phenomenology as a target for lattice QCD: Some recent beyond Standard Model phenomenology is based on new strongly\ninteracting dynamics of $SU(N)$ gauge fields coupled to various numbers of\nfermions. When $N=3$ these systems are analogues of QCD, although the fermion\nmasses are typically different from -- and heavier than -- the ones of real\nworld QCD. Many quantities needed for phenomenology from these models have been\ncomputed on the lattice. We are writing a guide for these phenomenologists,\ntelling them about lattice results. We'll tell you (some of) what they are\ninterested in knowing."
    },
    {
        "anchor": "The $\u03c1$ and $A$ mesons in strong abelian magnetic field in SU(2)\n  lattice gauge theory: We calculated correlators of vector, axial and pseudoscalar currents in\nexternal strong abelian magnetic field according to SU(2) gluodynamics. The\nmasses of neutral $\\rho$ and $A$ mesons with various spin projections to the\naxis parallel to the external magnetic field B have been calculated. We found\nthat the masses of neutral mesons with zero spin $s=0$ decrease in increasing\nmagnetic field, while the masses of the $\\rho$ and $A$ mesons with spin $s=\\pm\n1$ increase in the mentioned field. Also we performed extrapolation and\nrenormalization of masses on the lattice.",
        "positive": "Massive photons: an infrared regularization scheme for lattice QCD+QED: Standard methods for including electromagnetic interactions in lattice\nquantum chromodynamics calculations result in power-law finite-volume\ncorrections to physical quantities. Removing these by extrapolation requires\ncostly computations at multiple volumes. We introduce a photon mass to\nalternatively regulate the infrared, and rely on effective field theory to\nremove its unphysical effects. Electromagnetic modifications to the hadron\nspectrum are reliably estimated with a precision and cost comparable to\nconventional approaches that utilize multiple larger volumes. A significant\noverall cost advantage emerges when accounting for ensemble generation. The\nproposed method may benefit lattice calculations involving multiple charged\nhadrons, as well as quantum many-body computations with long-range Coulomb\ninteractions."
    },
    {
        "anchor": "The I=2 pipi S-wave Scattering Phase Shift from Lattice QCD: The pi+pi+ s-wave scattering phase-shift is determined below the inelastic\nthreshold using Lattice QCD. Calculations were performed at a pion mass of\nm_pi~390 MeV with an anisotropic n_f=2+1 clover fermion discretization in four\nlattice volumes, with spatial extent L~2.0, 2.5, 3.0 and 3.9 fm, and with a\nlattice spacing of b_s~0.123 fm in the spatial direction and b_t b_s/3.5 in the\ntime direction. The phase-shift is determined from the energy-eigenvalues of\npi+pi+ systems with both zero and non-zero total momentum in the lattice volume\nusing Luscher's method. Our calculations are precise enough to allow for a\ndetermination of the threshold scattering parameters, the scattering length a,\nthe effective range r, and the shape-parameter P, in this channel and to\nexamine the prediction of two-flavor chiral perturbation theory: m_pi^2 a r =\n3+O(m_pi^2/Lambda_chi^2). Chiral perturbation theory is used, with the Lattice\nQCD results as input, to predict the scattering phase-shift (and threshold\nparameters) at the physical pion mass. Our results are consistent with\ndeterminations from the Roy equations and with the existing experimental phase\nshift data.",
        "positive": "Critical Exponents for U(1) Lattice Gauge Theory at Finite Temperature: For compact U(1) lattice gauge theory (LGT) we have performed a finite size\nscaling analysis on $N_{\\tau} N_s^3$ lattices for $N_{\\tau}$ fixed and\n$N_s\\to\\infty$, approaching the phase transition from the confined phase. For\n$N_{\\tau}=4$, 5 and 6 our data contradict the expected scenario that this\ntransition is either first order or in the universality class of the 3d XY\nmodel. If there are no conceptional flaws in applying the argument that the\nGaussian fixed point in 3d is unstable to our systems, estimates of the\ncritical exponents $\\alpha/\\nu$, $\\gamma/\\nu$, $(1-\\beta)/\\nu$ and $2-\\eta$\nindicate the existence of a new, non-trivial renormalization group fixed point\nfor second order phase transitions in 3d. Such a fixed point would be of\nimportance for renormalization group theory and statistical physics."
    },
    {
        "anchor": "Emergence of the rho resonance from the HAL QCD potential: In this article, we report the $\\rho$ resonance study using the HAL QCD\nmethod. We calculate the $I=1$ $\\pi \\pi$ potential at $m_{\\pi} \\approx 0.41$\nGeV by a combination of the one-end trick, sequential propagator and covariant\napproximation averaging (CAA). Thanks to those techniques, we determine the\nnon-local $I=1$ $\\pi \\pi$ potential at the next-to-next-to-leading order\n(N$^2$LO) of the derivative expansion for the first time and obtain the pole of\nthe S-matrix corresponding to the $\\rho$ resonance. We also discuss the\ncomparison between our result and a previous calculation, done by L\\\"uscher's\nmethod.",
        "positive": "Leptonic D_s decays in two-flavour lattice QCD: We report on a two-flavour lattice QCD study of the D_s and D_s^* leptonic\ndecays parameterized by the decay constants f_{D_s} and f_{D_s^*}. As the\nphenomenology in the D_s sector seems very promising in the next years with the\nexperiments LHCb and Belle II, it is worth putting a big effort in lattice\ncomputations regarding its non-perturbative QCD contributions. Before examining\nmore challenging processes such as hadron-hadron transitions, a natural first\nstep is to address some basic aspects in the context of leptonic decays, where\nsystematic uncertainties from excited state contaminations and cut-off effects\nin the computation of charmed meson decay matrix elements can be investigated\nin a more straightforward setting."
    },
    {
        "anchor": "Precision SU(3) lattice thermodynamics for a large temperature range: We present the equation of state (pressure, trace anomaly, energy density and\nentropy density) of the SU(3) gauge theory from lattice field theory in an\nunprecedented precision and temperature range. We control both finite size and\ncut-off effects. The studied temperature window (0.7...1000 T_c) stretches from\nthe glueball dominated system into the perturbative regime, which allows us to\ndiscuss the range of validity of these approaches. We also determine the\npreferred renormalization scale of the Hard Thermal Loop scheme and we fit the\nunknown g^6 order perturbative coefficient at extreme high temperatures T>100\nT_c. We furthermore quantify the nonperturbative contribution to the trace\nanomaly using a simple functional form. Our high precision data allows one to\nhave a complete theoretical description of the equation of state from T=0 all\nthe way to the phase transition, through the transition region into the\nperturbative regime up to the Stefan-Boltzmann limit. We will discuss this\ndescription, too.",
        "positive": "The Sphaleron Rate at the Electroweak Crossover: The baryon number is violated in the Standard Model by non-perturbative\nsphaleron transitions. At temperatures above the electroweak scale, the rate of\nthe sphaleron transitions is unsuppressed and has been accurately measured\nusing effective theories on the lattice. At temperatures substantially below\nthe electroweak scale, the Higgs field expectation value is large and the\nsphaleron rate is strongly suppressed. Here analytical estimates are\nsufficient. The sphaleron rate, however, has not been calculated in the\nintermediate temperature range with physical Standard Model parameters. In this\nwork we use an effective electroweak theory on the lattice with multicanonical\nand real-time simulation methods to calculate the sphaleron rate through the\nelectroweak crossover at Higgs masses of 115 GeV and 160 GeV. The results are\nsignificant e.g. for Leptogenesis scenarios."
    },
    {
        "anchor": "Large-N QCD at strong transverse lattice gauge coupling: We had previously obtained an integral equation for mesons in transverse\nlattice QCD, in the limit of large number of colours and strong transverse\nlattice gauge coupling [1]. This equation is a generalisation of the 't Hooft\nequation [2], by inclusion of the spin degrees of freedom. We analyse this\nequation to extract spectral properties and light-front wavefunctions of\nmesons. We also extend the method to study baryon properties in the same limit.",
        "positive": "Nonabelian lattice theories: Consistent measures and strata: The role of consistent measures in the rigorous construction of nonabelian\nlattice theories is analized. General conditions that measures must fulfill to\ninsure consistency, positivity and a mass gap are obtained. The impact of\nnongeneric strata on the nature of the Hamiltonian lattice potential is also\ndiscussed."
    },
    {
        "anchor": "Moments of nucleon distribution amplitudes from irreducible three-quark\n  operators: Semi-exclusive and exclusive processes are becoming more and more important\nin high energy physics since they are excellently suited to study the internal\nhadronic structure. To analyze such processes the knowledge of the hadron\ndistribution amplitudes, which are universal for different reactions, is\nessential. Only rather indirect information on these nonperturbative functions\ncan be obtained from measurements. In this work we report on a lattice QCD\ncomputation of moments of nucleon distribution amplitudes using suitable\nthree-quark operators. However, these operators have to be renormalized and the\nmixing is even more complicated than in the continuum. Using the symmetry group\nof the hypercubic lattice we therefore derive and implement irreducibly\ntransforming three-quark operators, which allow us to control the mixing\npattern and will finally lead to quantitative predictions in the MSbar scheme.\nWe present preliminary results for leading-twist and next-to-leading twist\nnucleon distribution amplitudes based on the QCDSF/UKQCD simulations with 2\nflavors of dynamical clover fermions.",
        "positive": "Hadronic Light by Light Contributions to the Muon Anomalous Magnetic\n  Moment With Physical Pions: The current measurement of muonic $g - 2$ disagrees with the theoretical\ncalculation by about 3 standard deviations. Hadronic vacuum polarization (HVP)\nand hadronic light by light (HLbL) are the two types of processes that\ncontribute most to the theoretical uncertainty. The current value for HLbL is\nstill given by models. I will describe results from a first-principles lattice\ncalculation with a 139 MeV pion in a box of 5.5 fm extent. Our current\nnumerical strategies, including noise reduction techniques, evaluating the HLbL\namplitude at zero external momentum transfer, and important remaining\nchallenges, in particular those associated with finite volume effects, will be\ndiscussed."
    },
    {
        "anchor": "Stringy excitation and role of UV gluons in lattice QCD: Using SU(3) quenched lattice QCD, we study ground-state and low-lying\neven-parity excited-state potentials of quark-antiquark systems in terms of the\ngluon-momentum component in the Coulomb gauge. By introducing UV-cut in the\ngluon-momentum space, we investigate the \"UV-gluon sensitivity\" of the\nground-state and excited-state potentials and the stringy excitation\nquantitatively. Even after cutting off high-momentum gluon component above\n1.5GeV, the IR part of the ground-state potential is almost unchanged. On the\nother hand, the change of excited-state potential is more significant by the\ncut of UV-gluons. However, even after the removal of UV-gluons, the magnitude\nof the low-lying gluonic excitation remains to be of the order of 1GeV.",
        "positive": "Thermal Phase Transition in the NJL Model of QCD: We present results from numerical studies of the NJL model with two massless\nquarks at nonzero temperature. We show that the model undergoes a second order\nchiral phase transition which belongs to the 3d O(4) spin model universality\nclass."
    },
    {
        "anchor": "Monopoles and the Chiral Phase Transition in $SU(2)$ Lattice Gauge\n  Theory: In the quenched approximation we use the abelian and monopole fields from\nabelian projection in SU(2) lattice gauge theory to numerically compute the\nvalue of the chiral condensate. The condensate calculated using abelian\nprojection is observed to vanish at the same critical temperature as the full\nSU(2) theory predicts.",
        "positive": "QCD thermodynamics with stabilized Wilson fermions: Stabilized Wilson fermions are a reformulation of Wilson clover fermions that\nincorporates several numerical stabilizing techniques, but also a local change\nof the fermion action - the original clover term being replaced with an\nexponentiated version of it. We intend to apply the stabilized Wilson fermions\ntoolbox to the thermodynamics of QCD, starting on the $N_f=3$ symmetric line on\nthe Columbia plot, and to compare the results with those obtained with other\nfermion discretizations."
    },
    {
        "anchor": "Toward accurate form factors for $B$-to-light meson decay from lattice\n  QCD: We present the results of a lattice QCD calculation of the scalar and vector\nform factors for the unphysical $B_s\\to\\eta_s$ decay, over the full physical\nrange of $q^2$. This is a useful testing ground both for lattice QCD and for\nour wider understanding of the behaviour of form factors. Calculations were\nperformed using the highly improved staggered quark (HISQ) action on $N_f = 2 +\n1 + 1$ gluon ensembles generated by the MILC Collaboration with an improved\ngluon action and HISQ sea quarks. We use three lattice spacings and a range of\nheavy quark masses from that of charm to bottom, all in the HISQ formalism.\nThis permits an extrapolation in the heavy quark mass and lattice spacing to\nthe physical point and nonperturbative renormalisation of the vector matrix\nelement on the lattice. We find results in good agreement with previous work\nusing nonrelativistic QCD $b$ quarks and with reduced errors at low $q^2$,\nsupporting the effectiveness of our heavy HISQ technique as a method for\ncalculating form factors involving heavy quarks. A comparison with results for\nother decays related by SU(3) flavour symmetry shows that the impact of\nchanging the light daughter quark is substantial but changing the spectator\nquark has very little effect. We also map out form factor shape parameters as a\nfunction of heavy quark mass and compare to heavy quark effective theory\nexpectations for mass scaling at low and high recoil. This work represents an\nimportant step in the progression from previous work on heavy-to-heavy decays\n($b\\to c$) to the numerically more challenging heavy-to-light decays.",
        "positive": "First lattice evidence for a non-trivial renormalization of the Higgs\n  condensate: General arguments related to ``triviality'' predict that, in the broken phase\nof $(\\lambda\\Phi^4)_4$ theory, the condensate $<\\Phi>$ re-scales by a factor\n$Z_{\\phi}$ different from the conventional wavefunction-renormalization factor,\n$Z_{prop}$. Using a lattice simulation in the Ising limit we measure\n$Z_{\\phi}=m^2 \\chi$ from the physical mass and susceptibility and $Z_{prop}$\nfrom the residue of the shifted-field propagator. We find that the two $Z$'s\ndiffer, with the difference increasing rapidly as the continuum limit is\napproached. Since $Z_{\\phi}$ affects the relation of $<\\Phi>$ to the Fermi\nconstant it can sizeably affect the present bounds on the Higgs mass."
    },
    {
        "anchor": "Nucleon and $\u03a9$ Baryon Masses with All-HISQ Fermions at the\n  Physical Point: We present the results of the nucleon and $\\Omega$ baryon masses using\nstaggered action for both valence and sea quarks. Three ensembles with the\nphysical pion mass at approximate lattice spacings of $0.15$, $0.12$, and\n$0.088$fm are employed to extrapolate the masses to continuum and we obtain\n$M_N = 964(16)$ MeV and $M_\\Omega = 1678(9)$. Both statistical and systematic\nuncertainties are included in the nucleon mass, whereas only the statistical\nuncertainty is accounted for in the $\\Omega$ baryon mass.",
        "positive": "Are magnetic monopoles hadrons?: The charges of magnetic monopoles are constrained to a multiple of $2\\pi$\ntimes the inverse of the elementary unit electric charge. In the standard\nmodel, quarks have fractional charge, raising the question of whether the basic\nmagnetic monople unit is a multiple of $2 \\pi/e$ or three times that. A simple\nlattice construction shows how a magnetic monopole of the lower strength is\npossible if it interacts with gluonic fields as well. Such a monopole is thus a\nhadron. This is consistent with the construction of magnetic monopoles in grand\nunified theories."
    },
    {
        "anchor": "Determinant of a new fermionic action on a lattice - (I): We investigate, analytically and numerically, the fermion determinant of a\nnew action on a (1+1)-dimensional Euclidean lattice. In this formulation the\ndiscrete chiral symmetry is preserved and the number of fermion components is a\nhalf of that of Kogut-Susskind. In particular, we show that our fermion\ndeterminant is real and positive for U(1) gauge group under specific\nconditions, which correspond to gauge conditions on the infinite lattice. It is\nalso shown that the determinant is real and positive for SU(N) gauge group\nwithout any condition.",
        "positive": "How perturbative are heavy sea quarks?: Effects of heavy sea quarks on the low energy physics are described by an\neffective theory where the expansion parameter is the inverse quark mass,\n1/$M$. At leading order in 1/$M$ (and neglecting light quark masses) the\ndependence of any low energy quantity on $M$ is given in terms of the ratio of\n$\\Lambda$ parameters of the effective and the fundamental theory. We define a\nfunction describing the scaling with the mass $M$. We find that its\nperturbative expansion is very reliable for the bottom quark and also seems to\nwork very well at the charm quark mass. The same is then true for the ratios of\n$\\Lambda^{(4)}/\\Lambda^{(5)}$ and $\\Lambda^{(3)}/\\Lambda^{(4)}$, which play a\nmajor r\\^ole in connecting lattice determinations of $\\alpha^{(3)}_{MSbar}$\nfrom the three-flavor theory with $\\alpha^{(5)}_{MSbar}(M_Z)$. Also the charm\nquark content of the nucleon, relevant for dark matter searches, can be\ncomputed accurately from perturbation theory.\n  We investigate a very closely related model, namely QCD with $N_f=2$ heavy\nquarks. Our non-perturbative information is derived from simulations on the\nlattice, with masses up to the charm quark mass and lattice spacings down to\nabout 0.023 fm followed by a continuum extrapolation. The non-perturbative mass\ndependence agrees within rather small errors with the perturbative prediction\nat masses around the charm quark mass. Surprisingly, from studying solely the\nmassive theory we can make a prediction for the ratio\n$Q^{1/\\sqrt{t_0}}_{0,2}=[\\Lambda \\sqrt{t_0(0)}]_{N_f=2}/[\\Lambda\n\\sqrt{t_0}]_{N_f=0}$, which refers to the chiral limit in $N_f=2$. Here $t_0$\nis the Gradient Flow scale of [1]. The uncertainty for $Q$ is estimated to be\n2.5%. For the phenomenologically interesting $\\Lambda^{(3)}/\\Lambda^{(4)}$, we\nconclude that perturbation theory introduces errors which are at most at the\n1.5% level, far smaller than other current uncertainties."
    },
    {
        "anchor": "Computational Ergodicity of $s^4$: It is known that there are four-manifolds which are not algorithmically\nrecognizable. This implies that there exist triangulations of these manifolds\nwhich are separated by large barriers from the point of view of the computer\nalgorithm. We have not observed these barriers for triangulations of $S^4$.",
        "positive": "Thermodynamics of the ideal overlap quarks on the lattice: The thermodynamics of massless ideal gas of overlap quarks has been\ninvestigated both analytically and numerically for both zero and nonzero baryon\nchemical potential. Any \\mu^2-divergence is shown analytically to be absent for\na class of actions with nonzero chemical potential. All such actions are shown\nto violate chiral invariance. While the parameter M can be shown to be\nirrelevant in the continuum limit, as expected, it is shown numerically that\nthe continuum limit can be reached with relatively coarser lattices for certain\nranges of M. Numerical limitations of the existing method of introduction of\nchemical potential are demonstrated. Finally we also show that the energy\ndensity for the massive overlap fermions has the correct continuum limit."
    },
    {
        "anchor": "Anomaly at finite density and chiral fermions on lattice: Using both perturbation theory in the Euclidean formalism as well as the\nnon-perturbative Fujikawa's method, we verify that the chiral anomaly equation\nremains unaffected in continuum QCD in the presence of nonzero chemical\npotential, \\mu. We extend our considerations to lattice fermions with exact\nchiral symmetry and discuss the consequences for the recent Bloch-Wettig\nproposal for the Dirac operator at finite chemical potential. We propose a new\nsimpler method of incorporating \\mu.",
        "positive": "Spectrum of excited states using the stochastic LapH method: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Our first results in the zero-momentum bosonic I=1, S=0, T1u+\nsymmetry sector of QCD using a correlation matrix of 56 operators are\npresented. In addition to a dozen spatially-extended meson operators, 44\ntwo-meson operators are used, involving a wide variety of light isovector,\nisoscalar, and strange meson operators of varying relative momenta. All needed\nWick contractions are efficiently evaluated using a stochastic method of\ntreating the low-lying modes of quark propagation that exploits Laplacian\nHeaviside quark-field smearing. Level identification is discussed."
    },
    {
        "anchor": "Theta dependence in the large N limit: Studies of the large $N$ behaviour of the topological properties of gauge\ntheories typically focused on the large $N$ scaling of the topological\nsusceptibility. A much more difficult task is the study of the behaviour of\nhigher cumulants of the topological charge in the large $N$ limit, which up to\nnow remained elusive. We will present first results confirming the expected\nlarge $N$ scaling of the coefficient commonly denoted by $b_2$, related to the\nkurtosis of the topological charge.",
        "positive": "Transdimensional equivalence of universal constants for Fermi gases at\n  unitarity: I present lattice Monte Carlo calculations for a universal four-component\nFermi gas confined to a finite box and to a harmonic trap in one spatial\ndimension. I obtain the values xi_1d = 0.370(4) and xi_1d = 0.372(1),\nrespectively, for the Bertsch parameter, a nonperturbative universal constant\ndefined as the (square of the) energy of the untrapped (trapped) system\nmeasured in units of the free gas energy. The Bertsch parameter for the\none-dimensional system is consistent to within ~1% uncertainties with the most\nrecent numerical and experimental estimates of the analogous Bertsch parameter\nfor a three-dimensional spin-1/2 Fermi gas at unitarity. The finding suggests\nthe intriguing possibility that there exists a universality between two\nconformal theories in different dimensions. To lend support to this study, I\nalso compute continuum extrapolated ground state energies for four and five\nfermions confined to a harmonic trap and demonstrate the restoration of a\nVirial theorem in the continuum limit. The continuum few-body energies obtained\nare consistent with exact analytical calculations to within ~1.0% and ~0.25%\nstatistical uncertainties, respectively."
    },
    {
        "anchor": "Stochastic normalizing flows as non-equilibrium transformations: Normalizing flows are a class of deep generative models that provide a\npromising route to sample lattice field theories more efficiently than\nconventional Monte Carlo simulations. In this work we show that the theoretical\nframework of stochastic normalizing flows, in which neural-network layers are\ncombined with Monte Carlo updates, is the same that underlies\nout-of-equilibrium simulations based on Jarzynski's equality, which have been\nrecently deployed to compute free-energy differences in lattice gauge theories.\nWe lay out a strategy to optimize the efficiency of this extended class of\ngenerative models and present examples of applications.",
        "positive": "Parity doubling of nucleons, Delta and Omega baryons across the\n  deconfinement phase transition: In this work we analyse positive- and negative-parity channels for the\nnucleon (spin $1/2$ octet), $\\Delta$ and $\\Omega$ baryons (spin $3/2$ decuplet)\nusing lattice QCD. In Nature, at zero temperature, chiral symmetry is\nspontaneously broken, causing positive- and negative-parity ground states to\nhave different masses. However, chiral symmetry is expected to be restored (for\nmassless quarks) around the crossover temperature, implying that the two\nopposite parity channels should become degenerate. Here we study what happens\nin a temperature range which includes both the hadronic and the quark gluon\nplasma (QGP) phase. By analysing the correlation and spectral functions via\nexponential fits and the Maximum Entropy Method respectively, we have found\nparity doubling for the nucleon and $\\Delta$ baryon channels in the QGP phase.\nFor the $\\Omega$ baryon we see a clear signal of parity doubling at the\ncrossover temperature, which is however not complete, due to the nonzero\nstrange quark mass. Moreover, in-medium effects in the hadronic phase are\nevident for all three baryons, in particular for the negative-parity ground\nstates. This might have implications for the hadron resonance gas model. In\nthis work we used the FASTSUM anisotropic $N_f = 2 + 1$ ensembles."
    },
    {
        "anchor": "Computing the nucleon Dirac radius directly at $Q^2=0$: We describe a lattice approach for directly computing momentum derivatives of\nnucleon matrix elements using the Rome method, which we apply to obtain the\nisovector magnetic moment and Dirac radius. We present preliminary results\ncalculated at the physical pion mass using a 2HEX-smeared Wilson-clover action.\nFor removing the effects of excited-state contamination, the calculations were\ndone at three source-sink separations and the summation method was used.",
        "positive": "Static quark potential and string tension for compact U(1) in (2+1)\n  dimensions: Compact U(1) lattice gauge theory in (2+1) dimensions is studied on\nanisotropic lattices using Standard Path Integral Monte Carlo techniques. We\nextract the static quark potential and the string tension from 1.0 <= Dtau <=\n0.333 simulations at 1.0 <= beta <= 3.0. Estimating the actual value of the\nrenormalization constant, (c = 44), we observe the evidence of scaling in the\nstring tension for 1.4142 <= beta <= 2.5; with the asymptotic behaviour in the\nlarge-beta limit given by K sqrt(beta) = e^(-2.494 beta +2.29). Extrapolations\nare made to the extreme anisotropic or \"Hamiltonian\" limit, and comparisons are\nmade with previous estimates obtained by various other methods in the\nHamiltonian formulation."
    },
    {
        "anchor": "Lattice Charge Overlap II: Aspects of Charged Pion Polarizability: Formulas are developed for use in lattice studies of charged hadron\npolarizabilities. In particular, the valence quark different-flavor component\nof the charged pion polarizability is examined on a $16^{3}\\times 24$ lattice\nat $\\beta=6.0$ using Wilson fermions. Using the elastic limit results of Part I\nof this series, it is concluded that this represents a small negative component\nof the full charged polarizabilty.",
        "positive": "Lattice results for $D/D_s$ leptonic and semileptonic decays: This review article summarizes recent lattice QCD results for $D$ and $D_s$\nmeson leptonic and semileptonic decays. Knowing the meson decay constants and\nsemileptonic form factors from theory, one can extract CKM elements $V_{cd}$\nand $V_{cs}$ from experimental results. At present, the most accurate results\nfor decay constants are from the Fermilab Lattice and MILC Collaborations: $f_D\n= 212.5 \\pm 0.5_{\\mathrm{stat}} {}^{+0.6}_{-1.5} |_{\\mathrm{syst}}$ MeV and\n$f_{D_s} = 248.9 \\pm 0.2_{\\mathrm{stat}} {}^{+0.5}_{-1.6}|_{\\mathrm{syst}}$\nMeV, giving $V_{cd} = 0.2184 \\pm 0.009_{\\mathrm{expt}} {}^{+0.0008}_{-0.0016}\n|_{\\mathrm{lattice}}$ and $V_{cs} = 1.017 \\pm 0.02_{\\mathrm{expt}}\n{}^{+0.002}_{-0.007} |_{\\mathrm{lattice}}$. The shapes of the semileptonic form\nfactors from lattice QCD agree very well with experiment, and the accuracy is\ncurrently at the 2-5% level for $D \\to \\pi\\ell\\nu$ and 1-2% for $D \\to\nK\\ell\\nu$. Extracting the CKM elements from the semileptonic decays yields\n$V_{cd} = 0.225(6)_{\\mathrm{expt}}(10)_{\\mathrm{lattice}}$ (HPQCD\nCollaboration) and $V_{cs} = 0.963(5)_{\\mathrm{expt}}(14)_{\\mathrm{lattice}}$\n(HPQCD Collaboration). These lattice calculations also revealed that the\nsemileptonic form factors are insensitive to whether the spectator quark is a\nlight or strange quark."
    },
    {
        "anchor": "Simulation of Lattice Gauge Action from the Overlap Operator: We show the result of the lattice gauge field tensor which is derived from\nthe classical continuum limit of the overlap Dirac operator. By analogous\nconstruction, it was recently proposed that the gauge action can be obtained\nfrom the overlap operator as well which is proportional to Tr a D_{ov}. We\ndiscuss how to carry out Monte Carlo simulations of such a gauge action\ntogether with the overlap fermion.",
        "positive": "Heavy-light meson decay constants with N_f=3: During the past year the MILC Collaboration has continued its study of\nheavy-light meson decay constants with three dynamical quarks. Calculations\nhave been extended to a second lattice spacing of about 0.09 fm. At this\nlattice spacing, there are results in the quenched approximation and for three\nsets of dynamical quark mass: m_l=m_s; m_l=0.4 m_s and m_l=0.2 m_s, where m_l\nis the light mass for the u and d quarks and m_s is the strange quark mass. At\nthe coarser lattice spacing, for which results were presented at Lattice 2001,\nstatistics have been increased for two sets of quark masses and three\nadditional sets of quark masses have been studied, giving a total of eight\ncombinations used to interpolate between the quenched and chiral limits. When\nthese calculations are completed, we can study the decay constants taking into\naccount both chiral and continuum extrapolations."
    },
    {
        "anchor": "Parton physics from a heavy-quark operator product expansion: Lattice\n  QCD calculation of the second moment of the pion distribution amplitude: The pion light-cone distribution amplitude (LCDA) is a central\nnon-perturbative object of interest for high-energy exclusive processes in\nquantum chromodynamics. In this article, the second Mellin moment of the pion\nLCDA is determined as a proof-of-concept calculation for the first numerical\nimplementation of the heavy-quark operator product expansion (HOPE) method. The\nresulting value for the second Mellin moment, determined in quenched QCD at a\npion mass of $m_\\pi=550$ MeV at a factorization scale of 2 GeV is $ \\langle\n\\xi^2 \\rangle = 0.210 \\pm 0.013\\text{ (stat.)} \\pm 0.034\\text{ (sys.)}$. This\nresult is compatible with those from previous determinations of this quantity.",
        "positive": "Two-pole nature of the $\u039b(1405)$ from lattice QCD: This letter presents the first lattice QCD computation of the coupled channel\n$\\pi\\Sigma-\\bar{K}N$ scattering amplitudes at energies near $1405\\,{\\rm MeV}$.\nThese amplitudes contain the resonance $\\Lambda(1405)$ with strangeness $S=-1$\nand isospin, spin, and parity quantum numbers $I(J^P)=0(1/2^-)$. However,\nwhether there is a single resonance or two nearby resonance poles in this\nregion is controversial theoretically and experimentally. Using single-baryon\nand meson-baryon operators to extract the finite-volume stationary-state\nenergies to obtain the scattering amplitudes at slightly unphysical quark\nmasses corresponding to $m_\\pi\\approx200$ MeV and $m_K\\approx487$ MeV, this\nstudy finds the amplitudes exhibit a virtual bound state below the $\\pi\\Sigma$\nthreshold in addition to the established resonance pole just below the\n$\\bar{K}N$ threshold. Several parametrizations of the two-channel $K$-matrix\nare employed to fit the lattice QCD results, all of which support the two-pole\npicture suggested by $SU(3)$ chiral symmetry and unitarity."
    },
    {
        "anchor": "Representation of Complex Probabilities: Let a ``complex probability'' be a normalizable complex distribution $P(x)$\ndefined on $\\R^D$. A real and positive probability distribution $p(z)$, defined\non the complex plane $\\C^D$, is said to be a positive representation of $P(x)$\nif $\\langle Q(x)\\rangle_P = \\langle Q(z)\\rangle_p$, where $Q(x)$ is any\npolynomial in $\\R^D$ and $Q(z)$ its analytical extension on $\\C^D$. In this\npaper it is shown that every complex probability admits a real representation\nand a constructive method is given. Among other results, explicit positive\nrepresentations, in any number of dimensions, are given for any complex\ndistribution of the form Gaussian times polynomial, for any complex\ndistributions with support at one point and for any periodic Gaussian times\npolynomial.",
        "positive": "Higgs mass bounds from a chirally invariant lattice Higgs-Yukawa model\n  with overlap fermions: We study the parameter dependence of the Higgs mass in a chirally invariant\nlattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure\nas in the Higgs sector of the electroweak Standard Model. Eventually, the aim\nis to establish upper and lower Higgs mass bounds. Here we present our\npreliminary results on the lower Higgs mass bound at several selected values\nfor the cutoff and give a brief outlook towards the upper Higgs mass bound."
    },
    {
        "anchor": "Graphene: from materials science to particle physics: Since its discovery in 2004, graphene, a two-dimensional hexagonal carbon\nallotrope, has generated great interest and spurred research activity from\nmaterials science to particle physics and vice versa. In particular, graphene\nhas been found to exhibit outstanding electronic and mechanical properties, as\nwell as an unusual low-energy spectrum of Dirac quasiparticles giving rise to a\nfractional quantum Hall effect when freely suspended and immersed in a magnetic\nfield. One of the most intriguing puzzles of graphene involves the\nlow-temperature conductivity at zero density, a central issue in the design of\ngraphene-based nanoelectronic components. While suspended graphene experiments\nhave shown a trend reminiscent of semiconductors, with rising resistivity at\nlow temperatures, most theories predict a constant or even decreasing\nresistivity. However, lattice field theory calculations have revealed that\nsuspended graphene is at or near the critical coupling for excitonic gap\nformation due to strong Coulomb interactions, which suggests a simple and\nstraightforward explanation for the experimental data. In this contribution we\nreview the current status of the field with emphasis on the issue of gap\nformation, and outline recent progress and future points of contact between\ncondensed matter physics and Lattice QCD.",
        "positive": "A new framework to tune an improved relativistic heavy-quark action: We introduce a new non-perturbative method to tune the parameters of the\nColumbia formulation of an anisotropic, clover-improved relativistic\nheavy-quark (RHQ) action. By making use of suitable observables which can be\ncomputed at a sequence of heavy-quark mass values, employing an $O(a)$-improved\ndiscretized action with domain-wall chiral fermion, and safely interpolated\nbetween the accessible heavy-quark mass region and the static point predicted\nby heavy-quark effective theory, we are able to precisely determine the unknown\ncoefficients of the RHQ action. In this proof-of-principle study we benefit\nfrom the RBC/UKQCD Iwasaki gauge configurations with $2+1$ flavors of dynamical\nquarks, at three values of the lattice spacing varying from $0.11$ to $0.062$\nfm. Preliminary results and applications to bottom spectroscopy are also\npresented."
    },
    {
        "anchor": "Non-Perturbatively Improved Quenched Hadron Spectroscopy: We make a quenched lattice simulation of hadron spectroscopy at beta=6.2 with\nthe Wilson action non-perturbatively improved. With respect to the unimproved\ncase, the estimate of the lattice spacing is less influenced by the choice of\ninput hadron masses. We study also the effects of using an improved quark mass\nin the fits to the dependence of hadron masses upon quark masses.",
        "positive": "Gradient flow step-scaling function for SU(3) with twelve flavors: We calculate the step scaling function, the lattice analog of the\nrenormalization group $\\beta$-function, for an SU(3) gauge theory with twelve\nflavors. The gauge coupling of this system runs very slowly, which is reflected\nin a small step scaling function, making numerical simulations particularly\nchallenging. We present a detailed analysis including the study of systematic\neffects of our extensive data set generated with twelve dynamical flavors using\nthe Symanzik gauge action and three times stout smeared M\\\"obius domain wall\nfermions. Using up to $32^4$ volumes, we calculate renormalized couplings for\ndifferent gradient flow schemes and determine the step-scaling $\\beta$ function\nfor a scale change $s=2$ on up to five different lattice volume pairs. Our\npreferred analysis is fully $O(a^2)$ Symanzik improved and uses Zeuthen flow\ncombined with the Symanzik operator. We find an infrared fixed point within the\nrange $5.2 \\le g_c^2 \\le 6.4$ in the $c=0.250$ finite volume gradient flow\nscheme. We account for systematic effects by calculating the step-scaling\nfunction based on alternative flows (Wilson or Symanzik) as well as operators\n(Wilson plaquette, clover) and also explore the effects of the perturbative\ntree-level improvement."
    },
    {
        "anchor": "Light and Strange Hadron Spectroscopy with Dynamical Wilson Fermions: We present the final analysis of the light and strange hadron spectra from a\nfull QCD lattice simulation with two degenerate dynamical sea quark flavours at\n$\\beta = 5.6$ on a $16^3 \\times 32$ lattice. Four sets of sea quark masses\ncorresponding to the range $.69 \\leq m_\\pi/m_\\rho \\leq .83$ are investigated.\n  For reference we also ran a quenched simulation at $\\beta_{\\sf eff} = 6.0$,\nwhich is the point of equal lattice spacing, $a_{\\rho}^{-1}$. In the light\nsector, we find the chiral extrapolation to physical u- and d- masses to\npresent a major source of uncertainty, comparable to the expected size of\nunquenching effects. From linear and quadratic fits we can estimate the errors\non the hadron masses made from light quarks to be on a 15 % level prior to the\ncontinuum extrapolation. For the hadrons with strange valence quark content,\nthe $N_F = 2$ approximation to QCD appears not to cure the well-known failure\nof quenched QCD to reproduce the physical $K-K^*$ splitting.",
        "positive": "Enumeration of self avoiding trails on a square lattice using a transfer\n  matrix technique: We describe a new algebraic technique, utilising transfer matrices, for\nenumerating self-avoiding lattice trails on the square lattice. We have\nenumerated trails to 31 steps, and find increased evidence that trails are in\nthe self-avoiding walk universality class. Assuming that trails behave like $A\n\\lambda ^n n^{11 \\over 32}$, we find $\\lambda = 2.72062 \\pm 0.000006$ and $A =\n1.272 \\pm 0.002$."
    },
    {
        "anchor": "Long distance contribution to $K_{L}$-$K_{S}$ mass difference: We present a method to non-perturbatively determine the long-distance\ncontribution to the $K_{L}$-$K_{S}$ mass difference. The calculation is\nperformed on 2+1 flavor, domain wall fermion, $16^3\\times32$ configurations\nwith a 421 MeV pion mass and a kaon mass of 559 MeV . We include only\ncurrent-current operators and drop all disconnected diagrams in the\ncalculation. The largest contribution comes from quadratically divergent, short\ndistance lattice artifacts. This quadratic divergence is eliminated through the\nGIM mechanism by introducing a valence charm quark. The remaining short\ndistance effects are then removed by using RI/MOM technique which allows their\nexact replacement by the physical short distance part.",
        "positive": "Spectrum of the open QCD flux tube and its effective string description\n  I: 3d static potential in SU(N=2,3): We perform a high precision measurement of the static $q\\bar{q}$ potential in\nthree-dimensional SU($N$) gauge theory with $N=2,3$ and compare the results to\nthe potential obtained from the effective string theory. In particular, we show\nthat the exponent of the leading order correction in $1/R$ is 4, as predicted,\nand obtain accurate results for the continuum limits of the string tension and\nthe non-universal boundary coefficient $\\bar{b}_2$, including an extensive\nanalysis of all types of systematic uncertainties. We find that the magnitude\nof $\\bar{b}_2$ decreases with increasing $N$, leading to the possibility of a\nvanishing $\\bar{b}_2$ in the large $N$ limit. In the standard form of the\neffective string theory possible massive modes and the presence of a rigidity\nterm are usually not considered, even though they might give a contribution to\nthe energy levels. To investigate the effect of these terms, we perform a\nsecond analysis, including these contributions. We find that the associated\nexpression for the potential also provides a good description of the data. The\nresulting continuum values for $\\bar{b}_2$ are about a factor of 2 smaller than\nin the standard analysis, due to contaminations from an additional $1/R^4$\nterm. However, $\\bar{b}_2$ shows a similar decrease in magnitude with\nincreasing $N$. In the course of this extended analysis we also obtain\ncontinuum results for the masses appearing in the additional terms and we find\nthat they are around twice as large as the square root of the string tension in\nthe continuum and compatible between SU(2) and SU(3) gauge theory. In the\nfollow up papers we will extend our investigations to the large $N$ limit and\nexcited states of the open flux tube."
    },
    {
        "anchor": "Semi-analytical Proof of Abelian Dominance on Confinement in the\n  Maximally Abelian Gauge: We study abelian dominance for confinement in terms of the local gluon\nproperties in the maximally abelian (MA) gauge in a semi-analytical manner with\nthe help of the lattice QCD. The global Weyl symmetry persistently remains as\nthe relic of SU($N_c$) in the MA gauge, and provides the ambiguity on the\nelectric and magnetic charges. We derive the criterion on the SU($N_c$)-gauge\ninvariance in terms of the residual symmetry in the abelian gauge. In the\nlattice QCD, we find microscopic abelian dominance on the link variable for the\nwhole region of $\\beta$ in the MA gauge. The off-diagonal angle variable, which\nis not constrained by the MA-gauge fixing condition, tends to be random besides\nthe residual gauge degrees of freedom. Within the random-variable approximation\nfor the off-diagonal angle variable, we prove that off-diagonal gluon\ncontribution to the Wilson loop obeys the perimeter law in the MA gauge, and\nshow exact abelian dominance for the string tension, although small deviation\nis brought by the finite size effect of the Wilson loop in the actual lattice\nQCD simulation.",
        "positive": "Phase structure of lattice Yang-Mills theory on ${\\mathbb T}^2 \\times\n  {\\mathbb R}^2$: We study properties of SU(2) Yang-Mills theory on a four-dimensional\nEuclidean spacetime in which two directions are compactified into a finite\ntwo-dimensional torus ${\\mathbb T}^2$ while two others constitute a large\n${\\mathbb R}^2$ subspace. This Euclidean ${\\mathbb T}^2 \\times {\\mathbb R}^2$\nmanifold corresponds simultaneously to two systems in a (3+1) dimensional\nMinkowski spacetime: a zero-temperature theory with two compactified spatial\ndimensions and a finite-temperature theory with one compactified spatial\ndimension. Using numerical lattice simulations we show that the model exhibits\ntwo phase transitions related to the breaking of center symmetries along the\ncompactified directions. We find that at zero temperature the transition lines\ncross each other and form the Greek letter $\\gamma$ in the phase space\nparametrized by the lengths of two compactified spatial dimensions. There are\nfour different phases. We also demonstrate that the compactification of only\none spatial dimension enhances the confinement property and, consequently,\nincreases the critical deconfinement temperature."
    },
    {
        "anchor": "Improved lattice actions for supersymmetric quantum mechanics: We analyze the Euclidean version of supersymmetric quantum mechanics on the\nlattice by means of a numerical path integral. We consider two different\nlattice derivatives and improve the actions containing them with respect to\nsupersymmetry by systematically adding interaction terms with non-zero extent.\nTo quantize this improvement, we measure boson and fermion masses and Ward\nidentities for the naive as well as the improved models. The masses are\ndegenerate in all models, but the magnitude of the Ward identities decreases\nsignificantly for both derivative operators using the improved actions. This is\na clear sign that the breaking of supersymmetry due to lattice artifacts is\nreduced.",
        "positive": "Quenched Chiral Perturbation Theory for Baryons: We develop quenched chiral perturbation theory for baryons using the\ngraded-symmetry formalism of Bernard and Golterman and calculate non-analytic\ncontributions to the baryon masses coming from quenched chiral loops. The usual\nterm proportional to $m_{q}^{3/2}$ is substantially altered due to the\ncancellation of diagrams with internal quark loops. In addition, the $\\eta'$\n``hairpin'' vertex leads to a new correction, proportional to $m_{q}^{1/2}$. We\ncompare our results to numerical lattice data and use them to estimate the size\nof the quenching error in the octet baryon masses."
    },
    {
        "anchor": "Gribov copies and gauge variant correlators in U(1) lattice gauge theory: We discuss the influence of Dirac sheets and zero-momentum modes on the gauge\nvariant photon correlators $\\Gamma(\\tau;\\vp)$ with $\\vp\\ne 0$ and $\\vp =0$ in\nthe pure gauge U(1) theory. A special attention has been paid to the $\\beta$-\nand volume-dependence of this influence. Numerical simulations are performed on\n$12\\times 6^3$ and $24\\times 12^3$ lattices at different $y\\beta$'s in the\nCoulomb phase.",
        "positive": "Unbreaking chiral symmetry: In Quantum Chromodynamics (QCD) the eigenmodes of the Dirac operator with\nsmall absolute eigenvalues have a close relationship to the dynamical breaking\nof the chiral symmetry. In a simulation with two dynamical quarks, we study the\nbehavior of meson propagators when removing increasingly more of those modes in\nthe valence sector, thus partially removing effects of chiral symmetry\nbreaking. We find that some of the symmetry aspects are restored (e.g., the\nmasses of $\\rho$ and $a_1$ approach each other) while confining properties\npersist."
    },
    {
        "anchor": "A Relativistic $O(a^2)$ Improved Action for Heavy Quarks: We extend the Fermilab formalism for heavy quarks to develop an $O(a^2)$\nimproved relativistic action. We discuss our construction of the action,\nincluding the identification of redundant operators and the calculation of the\nimprovement coefficients.",
        "positive": "The Higgs boson resonance width from a chiral Higgs-Yukawa model on the\n  lattice: The Higgs boson is a central part of the electroweak theory and is crucial to\ngenerate masses for quarks, leptons and the weak gauge bosons. We use a\n4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the\nelectroweak model to compute physical quantities in the path integral approach\nwhich is evaluated by means of Monte Carlo simulations thus allowing for fully\nnon perturbative calculations. The chiral symmetry of the model is incorporated\nby using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa\nmodel does not involve the weak gauge bosons and furthermore, only a degenerate\ndoublet of top- and bottom quarks are incorporated. The goal of this work is to\nstudy the resonance properties of the Higgs boson and its sensitivity to the\nstrength of the quartic self coupling."
    },
    {
        "anchor": "Monopoles and Gluon Fields in QCD in the Maximally Abelian Gauge: We study monopoles and gluon fields in QCD in the maximally abelian (MA)\ngauge in the context of the dual superconductor picture for confinement. In the\nabelian gauge, unit-charge magnetic monopoles appear, but multi-charge\nmonopoles do not in general cases. The appearance of the monopole is studied\nusing the gauge-connection formalism in relation to the SU($N_c$) singular\ngauge transformation. The relevant role of off-diagonal gluons is found for the\nappearance of monopoles in the abelian gauge in QCD. We study the gluon-field\nproperties around the monopole in the MA gauge in terms of the action density\nusing the lattice QCD. The monopole provides infinitely large field\nfluctuations in the abelian sector. In the MA gauge, off-diagonal gluons are\nstrongly suppressed but largely remain around the monopole, which indicates the\neffective size and the structure of monopoles. We find the large cancellation\nbetween the abelian part and the off-diagonal part of the action density around\nthe monopole in the MA gauge. Owing to this cancellation, the monopole can\nappear in QCD without large cost of the QCD action. Finally, we generalize the\nframework of the abelian projection, {\\it i.e.} the extraction of the abelian\ngauge manifold from QCD, by introducing the `gluonic Higgs field' $\\vec\n\\phi_D[A_\\mu(x)]$ defined from the ${\\rm SU}(N_c)$ covariant derivative $\\hat\nD_\\mu$. By way of $\\vec \\phi_D[A_\\mu(x)]$, the maximally abelian projection can\nbe performed in the gauge-covariant manner without the notion of gauge fixing\nin principle.",
        "positive": "Density of states for gravitational waves: We present ongoing investigations of the first-order confinement transition\nof a composite dark matter model, to predict the resulting spectrum of\ngravitational waves. To avoid long autocorrelations at the first-order\ntransition, we employ the Logarithmic Linear Relaxation (LLR) density of states\nalgorithm. After testing our calculations by reproducing existing results for\ncompact U(1) lattice gauge theory, we focus on the pure-gauge SU(4) theory\nrelated to the Stealth Dark Matter model."
    },
    {
        "anchor": "A study of center and chiral symmetry realization in thermal\n  $\\mathcal{N}=1$ super Yang-Mills theory using the gradient flow: The realization of center and chiral symmetries in $\\mathcal{N}=1$ super\nYang-Mills theory (SYM) is investigated on a four-dimensional Euclidean lattice\nby means of Monte Carlo methods. At zero temperature this theory is expected to\nconfine external fundamental charges and to have a non-vanishing gaugino\ncondensate, which breaks the non-anomalous Z$_{2\\textrm{N}_{c}}$ chiral\nsymmetry. In previous studies at finite temperatures, the phase transitions\ncorresponding to deconfinement and chiral restoration were observed to occur at\nroughly the same critical temperature for SU(2) gauge group. We find further\nevidences for this observation from new measurements at smaller lattice\nspacings using the fermion gradient flow, and we discuss the agreement of our\nfindings with conjectures from superstring theory. The implementation of the\ngradient flow technique allows us also to estimate, for the first time, the\ncondensate at zero temperatures and zero gaugino mass with Wilson fermions.",
        "positive": "Instanton contributions to the low-lying hadron mass spectrum: The role of instanton-like objects in the QCD vacuum on the mass spectrum of\nlow-lying light hadrons is explored in lattice QCD. Using over-improved\nstout-link smearing, tuned to preserve instanton-like objects in the QCD\nvacuum, the evolution of the mass spectrum under smearing is examined. The\ncalculation is performed using a $20^3\\times40$ dynamical\nfat-link-irrelevant-clover (FLIC) fermion action ensemble with lattice spacing\n0.126 fm. Through the consideration of a range of pion masses, the effect of\nthe vacuum instanton content is compared at a common pion mass. While the\nqualitative features of ground-state hadrons are preserved on\ninstanton-dominated configurations, the excitation spectrum experiences\nsignificant changes. The underlying physics revealed shows little similarity to\nthe direct-instanton interaction predictions of the instanton liquid model."
    },
    {
        "anchor": "Fitting a sum of exponentials to lattice correlation functions using a\n  non-uniform prior: Excited states are extracted from lattice correlation functions using a\nnon-uniform prior on the model parameters. Models for both a single exponential\nand a sum of exponentials are considered, as well as an alternate model for the\northogonalization of the correlation functions. Results from an analysis of\ntorelon and glueball operators indicate the Bayesian methodology compares well\nwith the usual interpretation of effective mass tables produced by a\nvariational procedure. Applications of the methodology are discussed.",
        "positive": "Monte Carlo results for three-dimensional self-avoiding walks: We discuss possible sources of systematic errors in the computation of\ncritical exponents by renormalization-group methods, extrapolations from exact\nenumerations and Monte Carlo simulations. A careful Monte Carlo determination\nof the susceptibility exponent gamma for three-dimensional self-avoiding walks\nhas been used to test the claimed accuracy of the various methods."
    },
    {
        "anchor": "Beyond the Standard Model: Charting Fundamental Interactions via Lattice\n  Simulations: After the discovery of the Higgs boson, the primary objective of the Large\nHadron Collider (LHC) experiments is to identify new physics beyond the\nStandard Model (SM). One of the most intriguing possibilities would be the\ndiscovery of non-perturbative phenomena in electroweak physics. In fact both\nATLAS and CMS are providing crucial precision tests of the Higgs sector. Most\nstrikingly, there is no conclusive evidence yet on whether the Higgs boson is\nelementary or composite. Lattice simulations can play a key role in advancing\nour theoretical understanding of strongly coupled gauge theories relevant for\nextensions of the SM and the LHC program. In this talk I will review the state\nof beyond the SM (BSM) lattice studies aimed to chart the phase diagram and to\nuncover the properties of strongly coupled gauge theories.",
        "positive": "Lattice computation of the electromagnetic contributions to kaon and\n  pion masses: We present a lattice calculation of the electromagnetic (EM) effects on the\nmasses of light pseudoscalar mesons. The simulations employ 2+1 dynamical\nflavors of asqtad QCD quarks, and quenched photons. Lattice spacings vary from\n$\\approx 0.12$ fm to $\\approx 0.045$ fm. We compute the quantity $\\epsilon$,\nwhich parameterizes the corrections to Dashen's theorem for the $K^+$-$K^0$ EM\nmass splitting, as well as $\\epsilon_{K^0}$, which parameterizes the EM\ncontribution to the mass of the $K^0$ itself. An extension of the\nnonperturbative EM renormalization scheme introduced by the BMW group is used\nin separating EM effects from isospin-violating quark mass effects. We correct\nfor leading finite-volume effects in our realization of lattice electrodynamics\nin chiral perturbation theory, and remaining finite-volume errors are\nrelatively small. While electroquenched effects are under control for\n$\\epsilon$, they are estimated only qualitatively for $\\epsilon_{K^0}$, and\nconstitute one of the largest sources of uncertainty for that quantity. We find\n$\\epsilon = 0.78(1)_{\\rm stat}({}^{+\\phantom{1}8}_{-11})_{\\rm syst}$ and\n$\\epsilon_{K^0}=0.035(3)_{\\rm stat}(20)_{\\rm syst}$. We then use these results\non 2+1+1 flavor pure QCD HISQ ensembles and find $m_u/m_d = 0.4529(48)_{\\rm\nstat}( {}_{-\\phantom{1}67}^{+150})_{\\rm syst}$."
    },
    {
        "anchor": "Lattice searches for tetraquarks and mesonic molecules: light scalar\n  mesons and XYZ states: Searches for tetraquarks and mesonic molecules in lattice QCD are briefly\nreviewed. In the light quark sector the most serious candidates are the\nlightest scalar resonances sigma, kappa, a0 and f0. In the hidden-charm sector\nI discuss lattice simulations of X(3872), Y(4260), Y(4140) and Z^+(4430). The\nmost serious challenge in all these lattice studies is the presence of\nscattering states in addition to possible tetraquark/molecular states. The\navailable methods for distinguishing both are reviewed and the main conclusions\nof the simulations are presented.",
        "positive": "Scaling Lattice QCD beyond 100 GPUs: Over the past five years, graphics processing units (GPUs) have had a\ntransformational effect on numerical lattice quantum chromodynamics (LQCD)\ncalculations in nuclear and particle physics. While GPUs have been applied with\ngreat success to the post-Monte Carlo \"analysis\" phase which accounts for a\nsubstantial fraction of the workload in a typical LQCD calculation, the initial\nMonte Carlo \"gauge field generation\" phase requires capability-level\nsupercomputing, corresponding to O(100) GPUs or more. Such strong scaling has\nnot been previously achieved. In this contribution, we demonstrate that using a\nmulti-dimensional parallelization strategy and a domain-decomposed\npreconditioner allows us to scale into this regime. We present results for two\npopular discretizations of the Dirac operator, Wilson-clover and improved\nstaggered, employing up to 256 GPUs on the Edge cluster at Lawrence Livermore\nNational Laboratory."
    },
    {
        "anchor": "Where the electroweak phase transition ends: We give a more precise characterisation of the end of the electroweak phase\ntransition in the framework of the effective 3d SU(2)--Higgs lattice model than\nhas been given before. The model has now been simulated at gauge couplings\nbeta_G=12 and 16 for Higgs masses M_H^*=70, 74, 76 and 80 GeV up to lattices\n96^3 and the data have been used for reweighting. The breakdown of finite\nvolume scaling of the Lee-Yang zeroes indicates the change from a first order\ntransition to a crossover at lambda_3/g_3^2=0.102(2) in rough agreement with\nresults of Karsch et al (hep-lat/9608087) at \\beta_G=9 and smaller lattices.\nThe infinite volume extrapolation of the discontinuity Delta < phi^+ phi >\n/g_3^2 turns out to be zero at lambda_3/g_3^2=0.107(2) being an upper limit. We\ncomment on the limitations of the second method.",
        "positive": "The Shape of Covariantly Smeared Sources in Lattice QCD: Covariantly smeared sources are commonly used in lattice QCD to enhance the\nprojection onto the ground state. Here we investigate the dependence of their\nshape on the gauge field background and find that the presence of localized\nconcentrations of magnetic field can lead to strong distortions which reduce\nthe smearing radii achievable by iterative smearing prescriptions. In\nparticular, as $a\\to 0$, iterative procedures like Jacobi smearing require\nincreasingly large iteration counts in order to reach physically-sized smearing\nradii $r_{sm}\\sim$ 0.5 fm, and the resulting sources are strongly distorted. To\nbypass this issue, we propose a covariant smearing procedure (``free-form\nsmearing'') that allows us to create arbitrarily shaped sources, including in\nparticular Gaussians of arbitrary radius."
    },
    {
        "anchor": "Status of a minimal composite Higgs theory: We analyze three sets of gauge ensembles in our extended physics program of a\nparticularly important BSM gauge theory with a fermion doublet in the two-index\nsymmetric (sextet) representation of the SU(3) BSM color gauge group. Our\ninvestigations include chiral symmetry breaking $\\rm{(\\chi SB)}$ in the\np-regime and $\\epsilon$-regime, the mass of the composite ${\\rm 0^{++}}$\nscalar, resonance spectroscopy, new physics from gauge anomaly constraints, and\nthe role of stable sextet BSM baryons with Electroweak interactions in dark\nmatter searches. Important new goals include studies of the ${\\rm 0^{++}}$\nscalar entangled with Goldstone dynamics in the p-regime and the\n$\\epsilon$-regime, the resonance spectrum with particular attention to emerging\nLHC signals, like recent hints for diphoton excess at 750 GeV or diboson\nanomalies in the 2 TeV range. All results reported here are preliminary before\njournal publication including some post-conference material for the discussion.",
        "positive": "Fermion determinants in matrix models of QCD at nonzero chemical\n  potential: The presence of a chemical potential completely changes the analytical\nstructure of the QCD partition function. In particular, the eigenvalues of the\nDirac operator are distributed over a finite area in the complex plane, whereas\nthe zeros of the partition function in the complex mass plane remain on a\ncurve. In this paper we study the effects of the fermion determinant at nonzero\nchemical potential on the Dirac spectrum by means of the resolvent, G(z), of\nthe QCD Dirac operator. The resolvent is studied both in a one-dimensional U(1)\nmodel (Gibbs model) and in a random matrix model with the global symmetries of\nthe QCD partition function. In both cases we find that, if the argument z of\nthe resolvent is not equal to the mass m in the fermion determinant, the\nresolvent diverges in the thermodynamic limit. However, for z =m the resolvent\nin both models is well defined. In particular, the nature of the limit $z\n\\rightarrow m$ is illuminated in the Gibbs model. The phase structure of the\nrandom matrix model in the complex m and \\mu-planes is investigated both by a\nsaddle point approximation and via the distribution of Yang-Lee zeros. Both\nmethods are in complete agreement and lead to a well-defined chiral condensate\nand quark number density."
    },
    {
        "anchor": "Low-energy particle physics and chiral extrapolations: In this review I discuss the role of chiral extrapolations for the\ndetermination of several phenomenologically relevant quantities, including\nlight quark masses, meson decay constants and the axial charge of the nucleon.\nIn particular, I investigate whether chiral extrapolations are sufficiently\ncontrolled in order to rightfully claim the accuracy which is quoted in recent\ncompilations of these quantities. While this is the case for the masses of the\nlight quarks and the ratio fK/fpi of decay constants, small inconsistencies in\nthe chiral and continuum behaviour of individual decay constants fK and fpi, as\nwell as the hadronic radii r0, r1 remain and must be clarified. In the case of\nthe nucleon axial charge, gA, the chiral behaviour is still poorly understood\ndue to the presence of other systematic effects.",
        "positive": "Towards a precise lattice determination of the leading hadronic\n  contribution to (g-2)_mu: We report on our computation of the leading hadronic contribution to the\nanomalous magnetic moment of the muon using two dynamical flavours of\nnon-perturbatively O(a) improved Wilson fermions. The strange quark is\nintroduced in the quenched approximation. Partially twisted boundary conditions\nare applied to improve the momentum resolution in the relevant integral. Our\nresults, obtained at three different values of the lattice spacing, allow for a\npreliminary study of discretization effects. We explore a wide range of lattice\nvolumes, namely 2 fm < L < 3 fm, with pion masses from 600 to 280 MeV and\ndiscuss different chiral extrapolations to the physical point. We observe a\nnon-trivial dependence of a_mu(HLO) on m_pi especially for small pion masses.\nThe final result, a_mu(HLO)=618(64)*10^(-10), is obtained by considering only\nthe quark connected contribution to the vacuum polarization. We present a\ndetailed analysis of systematic errors and discuss how they can be reduced in\nfuture simulations."
    },
    {
        "anchor": "Effective noise reduction techniques for disconnected loops in Lattice\n  QCD: Many Lattice QCD observables of phenomenological interest include so-called\nall-to-all propagators. The computation of these requires prohibitively large\ncomputational resources, unless they are estimated stochastically. This is\nusually done. However, the computational demand can often be further reduced by\none order of magnitude by implementing sophisticated unbiased noise reduction\ntechniques. We combine both well known and novel methods that can be applied to\na wide range of problems. We concentrate on calculating disconnected\ncontributions to nucleon structure functions, as one realistic benchmark\nexample. In particular we determine the strangeness contributions to the\nnucleon, <N|ss|N>, and to the spin of the nucleon, Delta s.",
        "positive": "Correlation functions between topological objects -- field theoretic\n  versus geometric definitions: We analyze topological objects in pure gluonic $SU(2)$ lattice gauge theory\nand compute correlation functions between instantons and monopoles. Concerning\nthe instantons we use geometric and field theoretic definitions of the\ntopological charge. On a $12^3\\times 4$ lattice it turns out that topological\nquantities have a non-trivial local correlation. The auto-correlation functions\nof the topological charge depend on cooling for both definitions. We fit the\ncorrelation functions to exponentials and obtain screening masses."
    },
    {
        "anchor": "A factorization algorithm to compute Pfaffians: We describe an explicit algorithm to factorize an even antisymmetric N^2\nmatrix into triangular and trivial factors. This allows for a straight forward\ncomputation of Pfaffians (including their signs) at the cost of N^3/3 flops.",
        "positive": "Nucleon Electromagnetic Form Factors in the Continuum Limit from\n  2+1+1-flavor Lattice QCD: Results are presented for the nucleon isovector electromagnetic form factors\nusing 11 ensembles generated by the MILC collaboration using the 2+1+1-flavors\nHISQ action. They span 4 lattice spacings $a \\sim$ 0.06, 0.09, 0.12 and 0.15~fm\nand 3 values of $M_\\pi \\sim 135, 225$ and 315 MeV. High-statistics estimates\nare used to perform a simultaneous extrapolation in the lattice spacing,\nlattice volume and light-quark masses. The $Q^2$ dependence over the range\n0.05-1.4 ${\\rm GeV}^2$ is investigated using both the $z$-expansion and the\ndipole form. Final $z$-expansion estimates for the isovector r.m.s. radius are\n$r_E = 0.769(27)(30)$ fm $r_M = 0.671(48)(76)$ fm and $\\mu^{p-n} =\n3.939(86)(138)$ Bohr magneton. The first error is the combined uncertainty from\nthe leading-order analysis, and the second is an estimate of the additional\nuncertainty due to using the leading order chiral-continuum-finite-volume fits.\nThe dipole estimates, $r_E = 0.765(11)(8)$ fm, $r_M = 0.704(21)(29)$ fm and\n$\\mu^{p-n} = 3.975(84)(125)$, are consistent with those from the $z$-expansion\nbut with smaller errors. Our analysis highlights three points. First, all data\nfrom the eleven ensembles and existing lattice data on, or close to, physical\nmass ensembles from other collaborations collapses more clearly onto a single\ncurve when plotted versus $Q^2/M_N^2$ as compared to $Q^2$ with the scale set\nby quantities other than $M_N$. The difference between these two analyses is\nindicative of discretization errors, some of which presumably cancel when the\ndata are plotted versus $Q^2/M_N^2$. Second, the size of the remaining\ndeviation of this common curve from the Kelly curve is small and can be\naccounted for by statistical and possible systematic uncertainties. Third, to\nimprove lattice estimates, high statistics data for $Q^2 < 0.1$ ${\\rm GeV}^2$\nare needed."
    },
    {
        "anchor": "Composite flavor-singlet scalar in twelve-flavor QCD: We report the calculation of the flavor-singlet scalar in the SU(3) gauge\ntheory with the degenerate twelve fermions in the fundamental representation\nusing a HISQ-type action at a fixed $\\beta$. In order to reduce the large\nstatistical error coming from the vacuum-subtracted disconnected correlator, we\nemploy a noise reduction method and a large number of configurations. We\nobserve that the flavor-singlet scalar is lighter than the pion in this theory\nfrom the calculations with the fermion bilinear and gluonic operators. This\npeculiar feature is considered to be due to the infrared conformality of this\ntheory, and it is a promissing signal for a walking technicolor, where a light\ncomposite Higgs boson is expected to emerge by approximate conformal dynamics.",
        "positive": "Egalitarian Improvement to Democracy: Quark renormalization constants in\n  N_f=2 QCD: We present our results on the non-perturbative evaluation of the\nrenormalization constant for the quark field, $Z_q$, in Landau gauge within\nRI-MOM scheme. Using three lattice spacing we are able to isolate lattice\nartefacts of various origin, both perturbative and non-perturbative. In\nparticular, the existence of the dimension-two gluon-condensate is discussed,\nand confirmed."
    },
    {
        "anchor": "Exact Extended Supersymmetry on a Lattice: Twisted N=2 Super Yang-Mills\n  in Two Dimensions: We propose a lattice action for two dimensional super Yang-Mills theory with\na twisted N=2 supersymmetry. The extended supersymmetry is fully and exactly\nrealized on the lattice. The method employed is quite general and its extension\nto the N=4 supersymmetry in four dimensions is briefly presented. The lattice\nhas a new type of ``fermionic'' links, where odd Grassmann variables,\nsupercharges and fermionic connections sit. The Leibniz rule is preserved on\nthe lattice, although in a modified ``shifted'' form that takes into account\nthe link nature of both derivatives and supercharges. Superfields are\nsemi-local objects and superfield expansion is naturally embedded in the\nlattice structure. The Dirac-K\\\"ahler twist generates the extended twisted\nsupersymmetry, turning the multiplicity of species doublers into the\nmultiplicity due to the extended supersymmetry. In this way the balance between\nbosonic and fermionic degrees of freedom is preserved.",
        "positive": "Pseudoscalar transition form factors and the hadronic light-by-light\n  contribution to the muon $g-2$: We present preliminary results from our calculation of the pseudoscalar\ntransition form factors of the $\\eta$ and $\\eta'$ mesons using staggered quarks\non $N_f=2+1+1$ gauge ensembles generated by the Budapest-Marseille-Wuppertal\ncollaboration. These transition form factors are an important input for the\nhadronic light-by-light contribution to the muon $(g-2)$. We first elaborate on\nthe extraction of the masses of the $\\eta$ and $\\eta'$ mesons, that mix under\nthe dynamics of QCD. Thereafter, we show our preliminary results for the\npseudoscalar transition form factors, focusing on the $\\eta$ meson in the\nabsence of mixing."
    },
    {
        "anchor": "Lattice QCD determination of m_b, f_B and f_Bs with twisted mass Wilson\n  fermions: We present a lattice QCD determination of the b quark mass and of the B and\nB_s decay constants, performed with N_f=2 twisted mass Wilson fermions, by\nsimulating at four values of the lattice spacing. In order to study the b quark\non the lattice, two methods are adopted in the present work, respectively based\non suitable ratios with exactly known static limit and on the interpolation\nbetween relativistic data, evaluated in the charm mass region, and the static\npoint, obtained by simulating the HQET on the lattice. The two methods provide\nresults in good agreement. For the b quark mass in the MSbar scheme and for the\ndecay constants we obtain m_b(m_b)=4.29(14) GeV, f_B=195(12) MeV, f_Bs=232(10)\nMeV and f_Bs/f_B=1.19(5). As a byproduct of the analysis we also obtain the\nresults for the f_D and f_Ds decay constants: f_D=212(8) MeV, f_Ds=248(6) MeV\nand f_Ds/f_D=1.17(5).",
        "positive": "Transverse-Momentum-Dependent Wave Functions of Pion from Lattice QCD: We present a first lattice QCD calculation of the\ntransverse-momentum-dependent wave functions (TMDWFs) of the pion using\nlarge-momentum effective theory. Numerical simulations are based on one\nensemble with 2+1+1 flavors of highly improved staggered quarks action with\nlattice spacing $a=0.121$~fm from the MILC Collaboration, and one with 2 +1\nflavor clover fermions and tree-level Symanzik gauge action generated by the\nCLS Collaboration with $a=0.098$~fm. As a key ingredient, the soft function is\nfirst obtained by incorporating the one-loop perturbative contributions and a\nproper normalization. Based on this and the equal-time quasi-TMDWFs simulated\non the lattice, we extract the light-cone TMDWFs. The results are comparable\nbetween the two lattice ensembles and a comparison with phenomenological\nparametrization is made. Our studies provide a first attempt of $ab$ $initio$\ncalculation of TMDWFs which will eventually lead to crucial theory inputs for\nmaking predictions for exclusive processes under QCD factorization."
    },
    {
        "anchor": "Decay constants $f_B$ and $f_{B_s}$ from HISQ simulations: We give a progress report on a project aimed at a high-precision calculation\nof the decay constants $f_B$ and $f_{B_s}$ from simulations with HISQ heavy and\nlight valence and sea quarks. Calculations are carried out with several heavy\nvalence-quark masses on ensembles with 2+1+1 flavors of HISQ sea quarks at five\nlattice spacings and several light sea-quark mass ratios $m_{ud}/m_s$,\nincluding approximately physical sea-quark masses. This range of parameters\nprovides excellent control of the continuum limit and of heavy-quark\ndiscretization errors. We present a preliminary error budget with projected\nuncertainties of 2.2~MeV and 1.5~MeV for $f_B$ and $f_{B_s}$, respectively.",
        "positive": "Thermodynamics and reference scale of SU(3) gauge theory from gradient\n  flow on fine lattices: We study the parametrization of lattice spacing and thermodynamics of SU(3)\ngauge theory on the basis of the Yang-Mills gradient flow on fine lattices. The\nlattice spacing of the Wilson gauge action is determined over a wide range\n$6.3\\le\\beta\\le7.5$ with high accuracy. The measurements of the flow time and\nlattice spacing dependences of the expectation values of the energy-momentum\ntensor are performed on fine lattices."
    },
    {
        "anchor": "High loop renormalization constants for Wilson fermions/Symanzik\n  improved gauge action: We present the current status of our computation of quark bilinear\nrenormalization constants for Wilson fermions and Symanzik improved gauge\naction. Computations are performed in Numerical Stochastic Perturbation Theory.\nVolumes range from 10^4 to 32^4. Renormalization conditions are those of the\nRI'-MOM scheme, imposed at different values of the physical scale. Having\nmeasurements available at several momenta, irrelevant effects are taken into\naccount by means of hypercubic symmetric Taylor expansions. Finite volumes\neffects are assessed repeating the computations at different lattice sizes. In\nthis way we can extrapolate our results to the continuum limit, in infinite\nvolume.",
        "positive": "Chiral Yukawa models in the planar limit: We consider the most general renormalizable chiral Yukawa model with\n$SU(3)_{\\rm color}$ replaced by $SU(N_c)$, $SU(2)_{\\rm L}$ replaced by $SU(N_w\n)$ and $U(1)_{Y}$ replaced by $U(1)^{N_w -1}$ in the limit $N_c\n\\rightarrow\\infty$, $N_w \\rightarrow\\infty$ with the ratio\n$\\rho=\\sqrt{{N_w}\\over{N_c}} \\ne 0,\\infty$ held fixed. Since for $N_w \\ge 3$\nonly one renormalizable Yukawa coupling per family exists and there is no\nmixing between families the limit is appropriate for the description of the\neffects of a heavy top quark when all the other fermions are taken to be\nmassless. A rough estimate of the triviality bound on the Yukawa coupling is\nequivalent to $m_t \\le 1~TeV$."
    },
    {
        "anchor": "Nonequilibrium Aspects of Quantum Field Theory: We have developed a method for extracting equilibrium observables from\nnon-equilibrium simulations by rapidly changing the temperature and recording\nthe subsequent evolution of the Polyakov loop. Both nucleation and spinodal\ndecomposition are observed to occur. In the latter case the Polyakov loop\ncorrelation function shows exponential growth for wavenumbers less than or\nequal to the critical wavenumber k_c. We have constructed the bare as wee as\nthe effective potential for the Polyakov loop, from which k_c and m_D/k_c can\nbe extracted as a function of temperature. The shift from spinodal\ndecomposition to nucleation as the dominant equilibration mechanism occurs at\nthe spinodal temperature that separates these two regimes.",
        "positive": "On the behaviour of spatial Wilson loops in the high temperature phase\n  of Lattice Gauge Theories: The behaviour of the space-like string tension in the high temperature phase\nis studied. Data obtained in the $Z_2$ gauge model in (2+1) dimensions are\ncompared with predictions of a simple model of a fluctuating flux tube with\nfinite thickness. It is shown that in the high temperature phase contributions\ncoming from the fluctuations of the flux tube vanish. As a consequence we also\nshow that in (2+1) dimensional gauge theories the thickness of the flux tube\ncoincides with the inverse of the deconfinement temperature."
    },
    {
        "anchor": "Positive-parity Excited-states of the Nucleon in Quenched Lattice QCD: Positive-parity spin-1/2 excitations of the nucleon are explored in lattice\nQCD. The variational method is used in this investigation and several\ncorrelation matrices are employed. As our focus is on the utility and\nmethodology of the variational approach, we work in the quenched approximation\nto QCD. Various sweeps of Gaussian fermion-field smearing is applied at the\nsource and at the sink of $\\chi_{1}\\bar\\chi_{1}$ and $\\chi_{1}\\chi_{2}$\ncorrelation functions to obtain a large basis of operators. Using several\ndifferent approaches for constructing basis interpolators, we demonstrate how\nimproving the basis can split what otherwise might be interpreted as a single\nstate into multiple eigenstates. Consistency of the extracted excited energy\nstates are explored over various dimensions of the correlation matrices. The\nuse of large correlation matrices is emphasized for the reliable extraction of\nthe excited eigenstates of QCD.",
        "positive": "Chiral fermions on the lattice and index relations: Comparing recent lattice results on chiral fermions and old continuum results\nfor the index puzzling questions arise. To clarify this issue we start with a\ncritical reconsideration of the results on finite lattices. We then work out\nvarious aspects of the continuum limit. After determining bounds and norm\nconvergences we obtain the limit of the anomaly term. Collecting our results\nthe index relation of the quantized theory gets established. We then compare in\ndetail with the Atiyah-Singer theorem. Finally we analyze conventional\ncontinuum approaches."
    },
    {
        "anchor": "The Kaon B-parameter with the Wilson Quark Action using Chiral Ward\n  Identities: A lattice QCD calculation of the kaon $B$ parameter $B_K$ is carried out with\nthe Wilson quark action in the quenched approximation at $\\beta=6/g^2=5.9-6.5$.\nThe mixing problem of the $\\Delta s=2$ four-quark operators is solved\nnon-perturbatively with full use of chiral Ward identities employing four\nexternal quarks with an equal off-shell momentum in the Landau gauge. This\nmethod, without invoking any effective theory, enables us to construct the weak\nfour-quark operators exhibiting good chiral behavior. Our results for $B_K$\nwith the non-perturbative mixing coefficients show small scaling violation\nbeyond the lattice cut-off $a^{-1}\\sim 2.5 $GeV. Our estimate concludes\n$B_K(NDR, 2 GeV)=0.69(7)$ at $a^{-1}=2.7-4.3$GeV, which agrees with the value\nobtained with the Kogut-Susskind quark action. For comparison we also calculate\n$B_K$ with one-loop perturbative mixing coefficients. While this yields\nincorrect values at finite lattice spacing, a linear extrapolation to the\ncontinuum limit as a function of $a$ leads to a result consistent with those\nobtained with the Ward identity method.",
        "positive": "Mass Deformed Exact S-parameter in Conformal Theories: We use the exact expression for the S parameter in the perturbative region of\nthe conformal window to establish its dependence on the explicit introduction\nof fermion masses. We demonstrate that the relative ordering with which one\nsends to zero either the fermion mass or the external momentum leads to\ndrastically different limiting values of S. Our results apply to any fermion\nmatter representation and can be used as benchmark for the determination of\ncertain relevant properties of the conformal window of any generic vector like\ngauge theory with fermionic matter. We finally suggest the existence of a\nuniversal lower bound on the opportunely normalized S parameter and explore its\ntheoretical and phenomenological implications. Our exact results constitute an\nideal framework to correctly interpret the lattice studies of the conformal\nwindow of strongly interacting theories."
    },
    {
        "anchor": "Computation of the string tension in three dimensions using large N\n  reduction: We numerically compute the string tension in the large N limit of three\ndimensional Yang-Mills theory using Wilson loops. Space-time Wilson loops are\nformed using smeared space-like links and unsmeared time-like links. We use\npartial reduction and both unfolded and folded Wilson loops in the analysis.",
        "positive": "Center vortex model for the infrared sector of SU(3) Yang-Mills theory:\n  Topological susceptibility: The topological susceptibility of the SU(3) random vortex world-surface\nensemble, an effective model of infrared Yang-Mills dynamics, is investigated.\nThe model is implemented by composing vortex world-surfaces of elementary\nsquares on a hypercubic lattice, supplemented by an appropriate specification\nof vortex color structure on the world-surfaces. Topological charge is\ngenerated in this picture by writhe and self-intersection of the vortex\nworld-surfaces. Systematic uncertainties in the evaluation of the topological\ncharge, engendered by the hypercubic construction, are discussed. Results for\nthe topological susceptibility are reported as a function of temperature and\ncompared to corresponding measurements in SU(3) lattice Yang-Mills theory. In\nthe confined phase, the topological susceptibility of the random vortex\nworld-surface ensemble appears quantitatively consistent with Yang-Mills\ntheory. As the temperature is raised into the deconfined regime, the\ntopological susceptibility falls off rapidly, but significantly less so than in\nSU(3) lattice Yang-Mills theory. Possible causes of this deviation, ranging\nfrom artefacts of the hypercubic description to more physical sources, such as\nthe adopted vortex dynamics, are discussed."
    },
    {
        "anchor": "Three particles in a finite volume: Within the non-relativistic potential scattering theory, we derive a\ngeneralized version of the L\\\"uscher formula, which includes three-particle\ninelastic channels. Faddeev equations in a finite volume are discussed in\ndetail. It is proved that, even in the presence of the three-particle\nintermediate states, the discrete spectrum in a finite box is determined by the\ninfinite-volume elements of the scattering S-matrix up to corrections,\nexponentially suppressed at large volumes.",
        "positive": "TWQCD's dynamical DWF project: We present an overview of our project of simulation of unquenched lattice QCD\nwith optimal domain-wall quarks, using a GPU cluster currently constituting of\n16 units of Nvidia Tesla S1070 plus 64 graphic cards with Nvidia GTX285 (total\n128 GPUs with 128 Teraflops peak), attaining sustained computing power of 15.36\nTeraflops. The first production run in two-flavor QCD is on-going, using the\nIwasaki gauge action on a set of lattices with sizes $ 16^3 \\times\n(32,10,8,6,4) \\times (16,32) $ at the lattice spacing $ a \\sim 0.1$ fm, with\neight sea quark masses down to $ m_\\pi \\simeq 200 $ MeV. We outline our\nsimulation algorithm, and describe the present status of the production run.\nPreliminary results of pseudoscalar mass and decay constant are also presented."
    },
    {
        "anchor": "Dynamical fermion simulations using Luescher's local bosonic action\n  algorithm: The two-flavour Schwinger model is used to test the local boson action\nalgorithm of M Luescher. The autocorrelation time is found to rise linearly\nwith the number of auxiliary boson fields. An extension to the algorithm is\nproposed which exactly reproduces the full dynamical partition function for any\nnumber of boson fields.",
        "positive": "Renormalization of non-local gluon operators in lattice perturbation\n  theory: In this study, we investigate the renormalization of a complete set of\ngauge-invariant non-local gluon operators up to one-loop in lattice\nperturbation theory. Our computations have been performed in both dimensional\nand lattice regularizations, using the Wilson gluon action, leading to the\nrenormalization functions in the modified Minimal Subtraction\n$(\\overline{\\text{MS}})$ scheme, as well as conversion factors from the\nmodified regularization invariant $(RI')$ scheme to $\\overline{\\text{MS}}$."
    },
    {
        "anchor": "Quarkonia correlators and spectral functions from lattice QCD: I discuss recent progress in calculating quarkonia correlators and spectral\nfunctions on the lattice in relation with the problem of quarkonia dissolution\nat high temperatures and heavy quark transport in Quark Gluon Plasma.",
        "positive": "Recent results from heavy flavour physics on the lattice: We discuss some recent lattice results on a few selected hadronic quantities\nrelevant for heavy flavour phenomenology and present some recent theoretical\ndevelopments. We put the emphasis on the challenges, which have to be faced, on\nthe way to precise heavy flavour physics from the lattice. We also discuss the\nimportance in the search for New Physics of possible future lattice studies of\nthe form factors entering B --> K and B --> K* semileptonic decays."
    },
    {
        "anchor": "A Lecture on Chiral Fermions: This is an informal and approximate transcription of a talk presented at the\nDESY workshop, September 27--29, 1995. The basic message is that real and long\noverdue progress is taking place on the problem of regulating\nnon--perturbatively chiral gauge theories. Several approaches are reviewed with\nemphasis on the overlap and some of the questions raised about it. No claim for\ncompleteness or objectivity is made.",
        "positive": "Casimir Scaling vs. Abelian Dominance in QCD String Formation: We show that the hypothesis of abelian dominance in maximal abelian gauge,\nwhich is known to work for Wilson loops in the fundamental representation,\nfails for Wilson loops in higher group representations. Monte Carlo simulations\nare performed on lattice $SU(2)$ gauge theory, in $D=3$ dimensions, in the\nmaximal abelian gauge, in the confined phase. It is well-known that Creutz\nratios extracted from loops in various group representations are proportional\nto the quadratic Casimir of each representation, in a distance interval from\nthe confinement scale to the point where color screening sets in. In contrast\nwe find numerically, in the same interval, that string tensions extracted from\nloops built from abelian projected configurations are the same for the\nfundamental and $j=3/2$ representations, and vanish for the adjoint\nrepresentation. In addition, we perform a lattice Monte Carlo simulation of the\nGeorgi-Glashow model in $D=3$ dimensions. We find that the\nrepresentation-dependence of string tensions is that of pure Yang-Mills in the\nsymmetric phase, but changes abruptly to equal tensions for the $j=1/2,~3/2$\nrepresentations, and zero tension for $j=1$, at the transition to the Higgs\nphase. Our results indicate that an effective abelian theory at the confinement\nscale, invoking {\\it only} degrees of freedom (monopoles and photons)\nassociated with a particular Cartan subalgebra, is inadequate to describe the\nactual interquark potential in an unbroken non-abelian gauge theory."
    },
    {
        "anchor": "String-like theory as solution to the sign problem of a finite density\n  gauge theory: Z3 gauge theory with dynamical (bosonic) matter is studied in 4 dimensions\nwith a finite chemical potential. This theory could be viewed as an effective\ntheory describing the centre vortex picture of QCD colour confinement, but it\nis studied here with local interactions as theory in its own right. It is shown\nthat the sign-problem can be solved by dualisation. The dual theory is derived:\nthe pure gauge sector is a theory of closed membranes with Nambu-Goto action,\nand matter is described by open branes bounded by closed matter loops. The\nbrane theory is simulated with Monte-Carlo techniques. Some evidence is found\nthat the theory possesses a weakly-renormalisable phase with the scale set by a\nmass gap. Deconfinement at low temperatures and finite chemical potentials\nappears as a percolation transition for matter loops.",
        "positive": "Integrals over SU(N): In this paper we calculate a number of integrals over SU(N) of interest in\nHamiltonian Lattice Gauge Theory calculations."
    },
    {
        "anchor": "Comparison of the mass preconditioned HMC and the DD-HMC algorithm for\n  two-flavour QCD: Mass preconditioned HMC and DD-HMC are among the most popular algorithms to\nsimulate Wilson fermions. We present a comparison of the performance of the two\nalgorithms for realistic quark masses and lattice sizes. In particular, we use\nthe locally deflated solver of the DD-HMC environment also for the mass\npreconditioned simulations.",
        "positive": "Unqueched Kogut-Susskind quark propagator in Lattice Landau Gauge QCD: Quark propagators of the unquenched Kogut-Susskind(KS) fermion obtained from\nthe gauge configurations of the MILC collaboration are measured after Landau\ngauge fixing and using the Staple+Naik action. Presence of the $\\bar q q$\ncondensates and $A^2$ condensates in the dynamical mass $M(q)$ and the quark\nwave function renormalization $Z_\\psi(q^2)$ are investigated. We obtain the\ncorrelation of the renormalization factor of the running coupling taken at\n$\\mu\\sim 6$GeV and that of the quark wave function renormalization\n$Z_\\psi(q^2)$ of the Staple+Naik action. The mass function $\\displaystyle M(q)$\nis finite at $q=0$ and its chiral limit is $\\sim 0.38$GeV. We compared the\nresults corrected by the scale of the vertex renormalization and the tadpole\nrenormalization with the corresponding values obtained by the Asqtad action\nwithout renormalization and observed good agreement.Implication of infrared\nfinite $Z_2(q)=1/Z_\\psi(q^2)$ to the Kugo-Ojima confinement criterion is\ndiscussed."
    },
    {
        "anchor": "$B_c \\rightarrow J/\u03c8$ Form Factors for the full $q^2$ range from\n  Lattice QCD: We present the first lattice QCD determination of the $B_c \\rightarrow\nJ/\\psi$ vector and axial-vector form factors. These will enable experimental\ninformation on the rate for $B_c$ semileptonic decays to $J/\\psi$ to be\nconverted into a value for $V_{cb}$. Our calculation covers the full physical\n$q^2$ range of the decay and uses non-perturbatively renormalised lattice\ncurrents. We use the Highly Improved Staggered Quark (HISQ) action for all\nvalence quarks on the second generation MILC ensembles of gluon field\nconfigurations including $u$, $d$, $s$ and $c$ HISQ sea quarks. Our HISQ heavy\nquarks have masses ranging upwards from that of $c$; we are able to reach that\nof the $b$ on our finest lattices. This enables us to map out the dependence on\nheavy quark mass and determine results in the continuum limit at the $b$. We\nuse our form factors to construct the differential rates for $B_c^- \\rightarrow\nJ/\\psi \\mu^- \\bar{\\nu}_\\mu$ and obtain a total rate with $7\\%$ uncertainty:\n$\\Gamma(B_c^-\\rightarrow J/\\psi\n\\mu^-\\bar{\\nu}_{\\mu})/|\\eta_{\\mathrm{EW}}V_{cb}|^2 = 1.73(12)\\times 10^{13}\n~\\mathrm{s}^{-1}$. Including values for $V_{cb}$, $\\eta_{\\mathrm{EW}}$ and\n$\\tau_{B_c}$ yields a branching fraction for this decay mode of\n0.0150(11)(10)(3) ~with uncertainties from lattice QCD,\n$\\eta_\\mathrm{EW}V_{cb}$ and $\\tau_{B_c}$ respectively.",
        "positive": "A nonperturbative determination of c_A and the scaling of f_pi and\n  m^{MSbar}: We calculate the $O(a)$ improvement coefficient for the axial-vector current\nusing the nonperturbative method proposed by the LANL group. Results for the\ncoefficient in the range $\\beta=5.93$ to 6.2 are presented. We find $c_A$ is\nclose to the 1-loop tadpole-improved perturbative value. In addition, scaling\nof the pseudoscalar decay constant and renormalised quark mass is improved\ncompared to that obtained using the (larger) $c_A$ values obtained by the ALPHA\ncollaboration."
    },
    {
        "anchor": "Hadron Deformation and Form Factors from Lattice QCD: We review the current status of lattice QCD studies of the nucleon system. In\nparticular, we focus on the determination of the shape of the nucleon by\nprobing its wave function as well as by evaluating the N to Delta transition\nform factors.",
        "positive": "Gluon propagators and the choice of the gauge field in SU(2) theory on\n  the lattice: We study numerically magnetic $G_M(p)$ and electric $G_E(p)$ gluon\npropagators and their dependence on the choice of the lattice gauge field\n$\\caa_{x\\mu}$ in SU(2) gauge theory, especially, in the low--momentum limit. We\nfind that two different $\\caa_{x\\mu}$ definitions are equivalent up to a\ntrivial renormalization of the propagator, at least, in the main approximation."
    },
    {
        "anchor": "Confining Bond Rearrangement in the Random Center Vortex Model: We present static meson-meson and baryon--anti-baryon potentials in Z(2) and\nZ(3) random center vortex models for the infrared sector of Yang-Mills theory,\ni.e., hypercubic lattice models of random vortex world-surfaces. In particular,\nwe calculate Polyakov loop correlators of two static mesons resp.\n(anti-)baryons in a center vortex background and observe that their expectation\nvalues follow the minimal area law and show bond rearrangement behavior. The\nstatic meson-meson and baryon--anti-baryon potentials are compared with\ntheoretical predictions and lattice QCD simulations.",
        "positive": "Topology of dynamical lattice configurations including results from\n  dynamical overlap fermions: We investigate how the topological charge density in lattice QCD simulations\nis affected by violations of chiral symmetry caused by the fermion action. To\nthis end we compare lattice configurations generated with a number of different\nactions including first configurations generated with exact dynamical overlap\nquarks. We visualize the topological profiles after mild smearing. In the\ntopological charge correlator we measure the size of the positive core, which\nis known to shrink to zero extension in the continuum limit. To leading order\nwe find the core size to scale linearly with the lattice spacing with the same\ncoefficient for all actions, even including quenched simulations. In the\nsubleading term the different actions vary over a range of about 10 %. Our\nfindings suggest that non-chiral lattice actions at current lattice spacings do\nnot differ much for observables related to topology, both among themselves and\ncompared to overlap fermions."
    },
    {
        "anchor": "On decay width of heavy quarkonia in QGP: Quarkonia are some of the most important probes of the medium created in\nrelativistic heavy ion collision experiments, but it is still difficult to get\nquantitative results for its behavior in the plasma. Here I discuss the decay\nwidth of a heavy quarkonium system, and calculate the gluodissociation width of\nbottomonia. In the end I comment on study of quarkonia as open quantum systems.",
        "positive": "DMRG study of the higher-charge Schwinger model and its 't Hooft anomaly: The charge-$q$ Schwinger model is the $(1+1)$-dimensional quantum\nelectrodynamics (QED) with a charge-$q$ Dirac fermion. It has the\n$\\mathbb{Z}_q$ $1$-form symmetry and also enjoys the $\\mathbb{Z}_q$ chiral\nsymmetry in the chiral limit, and there is a mixed 't Hooft anomaly between\nthose symmetries. We numerically study the charge-$q$ Schwinger model in the\nlattice Hamiltonian formulation using the density-matrix renormalization group\n(DMRG). When applying DMRG, we map the Schwinger model to a spin chain with\nnonlocal interaction via Jordan-Wigner transformation, and we take the open\nboundary condition instead of the periodic one to make the Hilbert space\nfinite-dimensional. When computing the energy density or chiral condensate, we\nfind that using local operators significantly reduces the boundary effect\ncompared with the computation of corresponding extensive quantities divided by\nthe volume. To discuss the consequence of the 't Hooft anomaly, we carefully\ntreat the renormalization of the chiral condensates, and then we confirm that\nWilson loops generate the discrete chiral transformations in the continuum\nlimit."
    },
    {
        "anchor": "Single flavour optimisations to Hybrid Monte Carlo: It has become increasingly important to include one or more individual\nflavours of dynamical fermion in lattice QCD simulations. This is due in part\nto the advent of QCD+QED calculations, where isospin symmetry breaking means\nthat the up, down, and strange quarks must be treated separately. These\nsingle-flavour pseudofermions are typically implemented as rational\napproximations to the inverse of the fermion matrix, using the technique known\nas Rational Hybrid Monte Carlo (RHMC). Over the years, a wide range of methods\nhave been developed for accelerating simulations of two degenerate flavours of\npseudofermion, while there are comparatively fewer such techniques for\nsingle-flavour pseudofermions. Here, we investigate two different filtering\nmethods that can be applied to RHMC for simulating single-flavour\npseudofermions, namely polynomial filtering (PF-RHMC), and filtering via\ntruncations of the ordered product (tRHMC). A novel integration step-size\ntuning technique based on the characteristic scale is also introduced. Studies\nare performed on two different lattice volumes, demonstrating that one can\nachieve significant reductions in the computational cost of single-flavour\nsimulations with these filtering techniques.",
        "positive": "Magnetic catalysis (and inverse catalysis) at finite temperature in\n  two-color lattice QCD: Two-color lattice QCD with N_f=4 staggered fermion degrees of freedom (no\nrooting trick is applied) with equal electric charge q is studied in a\nhomogeneous magnetic background field B and at non-zero temperature T. In order\nto circumvent renormalization as a function of the bare coupling we apply a\nfixed-scale approach. We study the influence of the magnetic field on the\ncritical temperature. At rather small pseudo-scalar meson mass ($m_{\\pi}\n\\approx 175 \\mathrm{MeV} \\approx T_c(B=0)$) we confirm a monotonic rise of the\nquark condensate $<\\bar{\\psi} \\psi>$ with increasing magnetic field strength,\ni.e. magnetic catalysis, as long as one is staying within the confinement or\ndeconfinement phase. In the transition region we find indications for a\nnon-monotonic behavior of $T_c(B)$ at low magnetic field strength ($qB<0.8\n\\mathrm{GeV}^2$) and a clear rise at stronger magnetic field. The conjectured\nexistence of a minimum value $T_c(B^{*}) < T_c(B=0)$ would leave a temperature\nwindow for a decrease of $<\\bar{\\psi} \\psi>$ with rising $B$ (inverse magnetic\ncatalysis) also in the present model."
    },
    {
        "anchor": "Leading Isospin Breaking effects in nucleon and $\u0394$ masses: We present a lattice calculation of the leading corrections to the masses of\nnucleons and $\\Delta$ resonances. These are obtained in QCD+QED at $1$st order\nin the Isospin Breaking parameters $\\alpha_{EM}$, the electromagnetic coupling,\nand $\\frac{{\\hat{m}}_d - {\\hat{m}}_u}{\\Lambda_{QCD}}$, coming from the mass\ndifference between $u$ and $d$ quarks.",
        "positive": "Gradient flow, confinement, and magnetic monopole in U(1) lattice gauge\n  theory: In the gradient flow method of lattice gauge theory, coarse graining is\nperformed so as to reduce the action, and as the coarse graining progresses,\nthe field strength becomes very small. However, the confinement property that\nparticles interact strongly is not lost by the gradient flow. It is seemingly\nmysterious, and something stable against coarse graining is expected to be\nbehind the nature of confinement. By performing Monte Carlo simulations of U(1)\nlattice gauge theory, we discuss the relationship between the gradient flow and\nmagnetic monopoles created by the compactness of the U(1) gauge group. Many\nmagnetic monopoles are generated in the confinement phase but not so many in\nthe deconfinement phase. Since the monopole is a kind of topological quantity,\nthe number of monopoles does not change much by the coarse graining. To\ninvestigate why the confinement properties are not lost by the gradient flow,\nwe computed Wilson loops and Polyakov loops separating them into the field\nstrength and the monopole contributions. We found that the field strength,\nwhich decreases with the gradient flow, does not affect confinement properties,\nand the monopole and the confinement properties are strongly related.\nFurthermore, we discuss the relationship between the magnetic monopole and the\ncenter symmetry, which is the symmetry broken by the confinement phase\ntransition."
    },
    {
        "anchor": "The $\u03b5$-regime of dilaton chiral perturbation theory: The $\\epsilon$-regime of dilaton chiral perturbation theory is introduced. We\ncompute the dilaton mass, the chiral condensate and the topological\nsusceptibility in the $\\epsilon$-regime, as a function of the fermion mass. The\nmicroscopic spectral density of the Dirac operator is obtained from dilaton\nchiral perturbation theory. Our main result is that the chiral condensate and\nthe spectral density are related to their counterparts from ordinary chiral\nperturbation theory via a simple scaling relation. This relation originates\nfrom the mass dependence of the dilaton potential, and is valid in both the\n$\\epsilon$-regime and the $p$-regime. In the $\\epsilon$-regime, moreover, all\nresults agree with the universal predictions to leading order in $\\epsilon$.",
        "positive": "Excited States of the Nucleon in 2+1 Flavor QCD: Recent developments on the determination of the spin-1/2 spectrum of the\nnucleon in full QCD are presented. Our focus is on the PACS-CS 2+1 flavor\nconfigurations made available through the ILDG. Using correlation matrix\ntechniques, in which a wide variety of gauge-invariant Gaussian-smeared\nfermion-propagator sources and sinks are considered, excited states are\ndetermined. We consider several correlation matrices of various sizes, each\nconstructed with a different set of basis interpolators, in order to\ndemonstrate the invariance of the eigenstates on the basis choice. Of\nparticular interest is the approach to the elusive Roper resonance and we\nreport preliminary results in full QCD."
    },
    {
        "anchor": "Finite size scaling for 4-flavor QCD with finite chemical potential: We explore the phase diagram spanned by the temperature and the chemical\npotential for 4-flavor QCD by the phase-reweighting approach. In order to\ndetermine the order of phase transition, we perform finite size scaling studies\nfor various quantities, for example, susceptibility, kurtosis and\nChalla-Landau-Binder cumulant. At the parameter (beta=1.60, kappa=0.1371,\nc_sw=1.9655 and N_T=4), where the Kentucky group reported a first-order phase\ntransition in their canonical simulation, we observe that the transition is\nconsistent with being of first order.",
        "positive": "Comparison of finite-size-scaling functions for 3d O(N) spin models to\n  QCD: We calculate numerically universal finite-size-scaling functions of the\nmagnetization for the three-dimensional O(4) and O(2) spin models. The approach\nof these functions to the infinite-volume scaling functions is studied in\ndetail on the critical and pseudocritical lines. For this purpose we determine\nthe pseudocritical line in two different ways. We find that the asymptotic form\nof the finite-size-scaling functions is already reached at small values of the\nscaling variable. A comparison with QCD lattice data for two flavours of\nstaggered fermions shows a similar finite-size behaviour which is compatible\nwith that of the spin models."
    },
    {
        "anchor": "Two-colour QCD at non-zero temperature in the presence of a strong\n  magnetic field: In this talk we report on our study of two-colour lattice QCD with N_f=4\nstaggered fermion degrees of freedom with equal electric charge q in a\nhomogeneous magnetic field B at non-zero temperature T. We find indications for\na non-monotonic behaviour of the critical temperature as a function of the\nmagnetic field strength and, as a consequence, for the occurence of `inverse\nmagnetic catalysis' within the transition region for magnetic fields in the\nrange 0 < qB < 0.7 GeV^2.",
        "positive": "Eigenmodes of covariant Laplacian in SU(2) Yang-Mills vacuum: higher\n  representations: The study of lowest eigenmodes of the covariant Laplacian in fundamental\nrepresentation of the gauge group revealed their specific localization\nproperties. These may bear information on confinement of fundamental scalar\nparticles in SU(2) Yang-Mills vacuum. It was expected that scalar particle\neigenmodes in other representations would be localized in different physical\nvolumes. However simulations show strikingly different results for the adjoint\nand higher (J=3/2) representations. Apart from much higher extent of\nlocalization, we find evidence of different scaling behavior of localized\neigenmodes."
    },
    {
        "anchor": "Lattice Results for Vector Meson Couplings and Parton Distribution\n  Amplitudes: We present results for the couplings of light vector mesons to vector and\ntensor currents and on the low moments of the light-cone distribution\namplitudes of the pion and kaon. The calculations are performed on the RBC and\nUKQCD collaborations' ensembles generated with the Iwasaki gauge action and\nwith 2+1 flavours of domain wall fermions. The (preliminary) results for the\nratios of the couplings of the vector meson to the vector and tensor currents\n(f_V and f^T_V respectively) in the MSbar scheme at 2GeV are:\nf_\\rho^T/f_\\rho=0.681(20); f_{K^\\ast}^T/f_{K^\\ast}=0.712(11) and\nf_\\phi^T/f_\\phi=0.751(9). For the first moment of the kaon's distribution\namplitude we find (in the same scheme and at the same scale) <xi>_K=0.029(2)\nand for the second moment <xi^2>_\\pi=0.28(3) and <xi^2>_K=0.27(2).",
        "positive": "Estimating excited states contamination of $B \\to \u03c0$ form factors\n  using heavy meson chiral perturbation theory: Using Heavy Meson Chiral Perturbation Theory (HMChPT), the $B^* \\pi$ excited\nstates contamination of the $B \\to \\pi$ vector form factors is computed to NLO\nin the chiral expansion and in the static limit. The results suggest that the\nexcited states for $h_\\parallel$ are of the order of a few percent whereas\n$h_\\perp$ receives large negative contributions and thus might be significantly\nunderestimated in lattice simulations."
    },
    {
        "anchor": "Hamiltonian lattice gauge theory: wavefunctions on large lattices: We discuss an algorithm for the approximate solution of Schrodinger's\nequation for lattice gauge theory, using lattice SU(3) as an example. A basis\nis generated by repeatedly applying an effective Hamiltonian to a ``starting\nstate.'' The resulting basis has a cluster decomposition and long-range\ncorrelations. One such basis has about 10^4 states on a 10X10X10 lattice. The\nHamiltonian matrix on the basis is sparse, and the elements can be calculated\nrapidly. The lowest eigenstates of the system are readily calculable.",
        "positive": "Quark Confinement in Multi-Flavor Quantum Chromodynamics: It is investigated how quark confinement depends on the number of flavors,\n$N_f$, in QCD on the lattice with Wilson quarks. We strengthen and extend the\nconclusion reported at {\\it Lattice 91}: (1) For $N_f \\le 6$ the finite\ntemperature deconfining transition/crossover line crosses the chiral limit at\nfinite $\\beta$. We identify the crossing point for $N_f=2$ and 6 on a $T=4$\nlattice, where $T$ is the lattice size in the temporal direction. We find the\nphase transition at the crossing point is continuous for $N_f=2$, while it is\nof first order for $N_f=6$. (2) For $N_f \\ge 7$, the $T$-independent\ndeconfining transition observed at $\\beta=0$ extends up to $\\beta=4.5$ with the\ncritical quark mass $m_{\\rm quark} = O(a^{-1})$, where $a$ is the lattice\nspacing."
    },
    {
        "anchor": "Statistical tweaks and flow scale from masses: We compare lattice scales determined from the vector meson mass and the\nWilson flow scale w_0 in QCD with two-flavours of rooted naive staggered\nfermions over a wide range of lattice spacing and quark mass. We find that the\ndistributions of meson correlation functions are non-Gaussian. We modify the\nstatistical analysis to take care of the non-Gaussianity. Current day\nimprovements in the statistical quality of data on hadron correlations further\nallow us to simplify certain aspects of the analysis of masses. We examine\nthese changes through the analysis of pions and apply them to the vector meson.\nWe compare the flow scale determined using the rho mass with that using\nLambda_{MSbar}.",
        "positive": "Complex Langevin dynamics for SU(3) gauge theory in the presence of a\n  theta term: One of the yet unsolved questions of QCD in the context of the Standard Model\nis to explain the strong CP problem. A way to look for a better understanding\nof it is to investigate the theory in the presence of a non-zero topological\ntheta term. On the lattice such a term is complex: hence it introduces a sign\nproblem which, in general, limits the applicability of standard Monte Carlo\nmethods. Here we will discuss the approach of complex Langevin dynamics and\nshow results for both real and imaginary values of theta. We also report on our\nexperience with the gradient flow for real and imaginary theta."
    },
    {
        "anchor": "Non-renormalization theorem in a lattice supersymmetric theory and the\n  cyclic Leibniz rule: N=4 supersymmetric quantum mechanical model is formulated on the lattice. Two\nsupercharges, among four, are exactly conserved with the help of the cyclic\nLeibniz rule without spoiling the locality. In use of the cohomological\nargument, any possible local terms of the effective action are classified into\ntwo categories which we call type-I and type-II, analogous to the D- and\nF-terms in the supersymmetric field theories. We prove non-renormalization\ntheorem on the type-II terms which include mass and interaction terms with\nkeeping a lattice constant finite, while type-I terms such as the kinetic terms\nhave nontrivial quantum corrections.",
        "positive": "Review on the inclusion of isospin breaking effects in lattice\n  calculations: Isospin symmetry is explicitly broken in the Standard Model by the non-zero\ndifferences of mass and electric charge between the up and down quarks. Both of\nthese corrections are expected to have a comparable size of the order of one\npercent relatively to hadronic energies. Although these contributions are\nsmall, they play a crucial role in hadronic and nuclear physics. In this review\nwe explain how to properly define QCD and QED on a finite and discrete\nspace-time so that isospin corrections to hadronic observables can be computed\nab-initio. We then consider the different approaches to compute lattice\ncorrelation functions of QCD and QED observables. Finally we summarise the\nactual lattice results concerning the isospin corrections to the light hadron\nspectrum."
    },
    {
        "anchor": "A pion decay constant in the multi-flavor Schwinger model: The pion decay constant $F_{\\pi}$ plays an important role in QCD and in\nChiral Perturbation Theory. It is hardly known, however, that a corresponding\nconstant exists in the Schwinger model with $N_{\\rm f} \\geq 2$ degenerate\nfermion flavors. In this case, the ``pion'' does not decay and $F_{\\pi}$is\ndimensionless. Still, $F_{\\pi}$ can be defined by 2d analogies to the\nGell-Mann--Oakes--Renner relation, the Witten--Veneziano formula and the\nresidual ``pion'' mass in the $\\delta$-regime. With suitable assumptions, and\nby inserting simulation data, these QCD-inspired relations are all compatible\nwith $F_{\\pi} \\simeq 1/\\sqrt{2\\pi}$ at zero fermion mass, as we observe for\n$N_{\\rm f} = 2, \\dots , 6$. We conclude that this is a meaningful constant in\nthe multi-flavor Schwinger model.",
        "positive": "Dyson's Instability in Lattice Gauge Theory: We discuss Dyson's argument that the vacuum is unstable under a change g^2 ->\n- g^2, in the context of lattice gauge theory. For compact gauge groups, the\npartition function is well defined at negative g^2, but the average plaquette P\nhas a discontinuity when g^2 changes sign. This reflects a change of vacuum\nrather than a loss of vacuum. In addition, P has poles in the complex g^2\nplane, located at the complex zeros of the partition function (Fisher's zeros).\nWe discuss the relevance of these singularities for lattice perturbation\ntheory. We present new methods to locate Fisher's zeros using numerical values\nfor the density of state in SU(2) and U(1) pure gauge theory. We briefly\ndiscuss similar issues for O(N) nonlinear sigma models where the local\nintegrals are also over compact spaces."
    },
    {
        "anchor": "Is strong CP invariance due to a massless up quark?: A standing mystery in the Standard Model is the unnatural smallness of the\nstrong CP violating phase. A massless up quark has long been proposed as one\npotential solution. A lattice calculation of the constants of the chiral\nLagrangian essential for the determination of the up quark mass, 2 alpha_8 -\nalpha_5, is presented. We find 2 alpha_8 - alpha_5 = 0.29 +/- 0.18, which\ncorresponds to m_u / m_d = 0.410 +/- 0.036. This is the first such calculation\nusing a physical number of dynamical light quarks, N_f = 3.",
        "positive": "Probing the QCD vacuum with overlap fermions: We use low lying eigenvectors of the overlap-Dirac operator as a probe of the\nQCD vacuum. If instantons play a significant role one would expect the low\nlying eigenmodes of the overlap-Dirac operator to consist mainly of the mixed\n``would be zero modes''. Then, the eigenmodes should exhibit local chirality.\nStudying a recently introduced local chirality parameter, we find evidence\nsupporting this picture."
    },
    {
        "anchor": "Dynamical fermions, centre vortices, and emergent phenomena: The non-trivial ground-state vacuum fields of QCD form the foundation of\nmatter. Here we examine the centre vortices identified within the ground-state\nfields of lattice QCD. We aim to understand the manner in which dynamical\nfermions in the QCD vacuum alter the centre-vortex structure. Using modern\nvisualisation techniques, the centre-vortex structure of pure-gauge and\ndynamical-fermion fields is quantified and compared. We then explore the impact\nthis modified structure has on measures of confinement and dynamical mass\ngeneration. The string tension of the static quark potential,\npositivity-violation in the gluon propagator, and dynamical mass generation in\nthe overlap quark propagator are of particular interest. The impact of\ndynamical fermions is significant and provides new insights into the role of\ncentre vortices in underpinning both confinement and dynamical chiral symmetry\nbreaking in QCD.",
        "positive": "Two-loop relation between the bare lattice coupling and the MSbar\n  coupling in pure SU(N) gauge theories: We report the result of a computation of the relation between the\nrenormalized coupling in the MSbar scheme of dimensional regularization and the\nbare coupling in the standard lattice formulation of the SU(N) Yang-Mills\ntheory to two-loop order of perturbation theory and discuss some of its\nimplications."
    },
    {
        "anchor": "Machine learning mapping of lattice correlated data: We discuss a novel approach based on machine learning (ML) regression models\nto reduce the computational cost of disconnected diagrams in lattice QCD\ncalculations. This method creates a mapping between the results of fermionic\nloops computed at different quark masses and flow times. The ML model, trained\nwith just a small fraction of the complete data set, provides similar\npredictions and uncertainties over the calculation done over the whole\nensemble, resulting in a significant computational gain.",
        "positive": "Chiral Effects of Quenched Eta-Prime Loops: Preliminary results of a study of quenched chiral logarithms at beta=5.7 are\npresented. Four independent determinations of the quenched chiral log parameter\ndelta are obtained. Two of these are from estimates of the eta-prime mass, one\nfrom the residue of the hairpin diagram and the other from the topological\nsusceptibility combined with the Witten-Veneziano formula. The other two\ndeterminations of delta are from measurement of virtual eta-prime loop effects\nin mpi^2 vs. quark mass and in the chiral behavior of the pseudoscalar decay\nconstant. All results are consistent with delta=.080(15). The expected absence\nof quenched chiral logs in the axial-vector decay constant is also observed."
    },
    {
        "anchor": "Structure Functions, Form Factors, and Lattice QCD: We present results towards the calculation of the pion electric form factor\nand structure function on a $16^3\\times 24$ lattice using charge overlap. By\nsacrificing Fourier transform information in two directions, it is seen that\nthe longitudinal four point function can be extracted with reasonable error\nbars at low momentum.",
        "positive": "One-Loop Self Energy and Renormalization of the Speed of Light for some\n  Anisotropic Improved Quark Actions: One-loop corrections to the fermion rest mass M_1, wave function\nrenormalization Z_2 and speed of light renormalization C_0 are presented for\nlattice actions that combine improved glue with clover or D234 quark actions\nand keep the temporal and spatial lattice spacings, a_t and a_s, distinct. We\nexplore a range of values for the anisotropy parameter \\chi = a_s/a_t and treat\nboth massive and massless fermions."
    },
    {
        "anchor": "Multiresolution decomposition of quantum field theories using wavelet\n  bases: We investigate both theoretical and computational aspects of using wavelet\nbases to decouple physics on different scales in quantum field theory.",
        "positive": "Mesonic String of Diquark-Quark Configuration at Finite Temperature: We investigate the distance and temperatures scale for which the string in\nbaryonic quark configuration approaches the limiting behavior of mesonic\nstrings in pure Yang-Mills SU(3) lattice gauge theory. We calculate and compare\nthe numerical values of the Polyakov loop correlators and the width profile of\nboth diquark-quark $(QQ)Q$ and mesonic $Q\\bar{Q}$ strings. We find the\ndiquark-quark configuration to exhibit an identical behavior to the mesonic\nstring for the potential and energy-density width profile for temperature near\nthe end of QCD plateau. In the vicinity of the deconfinement point; however,\nthe symmetry in the energy-width profile with the meson does not manifest at\nboth short and intermediate distance scales. Moreover, we observe significantly\ndifferent numerical values for Polyakov loop correlators corresponding to each\nsystem. The splitting of the two identical system suggest that, in the high\ntemperature region of the confined phase of QCD, the subsisted baryonic\ndecouplet states overlap with the excited mesonic spectrum yielding the\ndiquark-quark symmetry with the meson inexact in a small enough neighborhood of\nthe critical point $T_{c}$."
    },
    {
        "anchor": "Lattice investigation of heavy meson interactions: We report on a lattice investigation of heavy meson interactions and of\ntetraquark candidates with two very heavy quarks. These two quarks are treated\nin the static limit, while the other two are up, down, strange or charm quarks\nof finite mass. Various isospin, spin and parity quantum numbers are\nconsidered.",
        "positive": "The thermodynamics of heavy light hadrons at freezeout: In the discussion of hadronization at or close to the freeze-out curve\nstatistical (hadron resonance gas) models play an important role. In\nparticular, in the charmonium sector, regeneration models are considered which\nrely on the fact that charmonium states can form again already at temperatures\nwell above the QCD transition or hadronization temperature. An important\ningredient in these considerations is the regeneration or hadronization of open\ncharm states. In this talk we report on a lattice QCD analysis of correlations\nof open strange and charm with other conserved quantum numbers like the net\nbaryon number and electric charge. We analyze the temperature range in which an\nuncorrelated hadron resonance gas (HRG) provides an adequate description of\nsuch correlations. This limits the range of validity of HRG based\nthermodynamics in open flavor channels and provides an estimate for the melting\ntemperature of heavy-light hadrons."
    },
    {
        "anchor": "On U(1) Gauge Theory Transfer-Matrix in Fourier Basis: The properties of the transfer-matrix of U(1) lattice gauge theory in the\nFourier basis are explored. Among other statements it is shown: 1) the\ntransfer-matrix is block-diagonal, 2) all consisting vectors of a block are\nknown based on an arbitrary block vector, 3) the ground-state belongs to the\nzero-mode's block. The emergence of maximum-points in matrix-elements as\nfunctions of the gauge coupling is clarified. Based on explicit expressions for\nthe matrix-elements we present numerical results as tests of our statements.",
        "positive": "High Precision Verification of the Kosterlitz Thouless Scenario: We verify the Kosterlitz Thouless scenario for three different SOS\n(solid-on-solid) models, including the dual transforms of XY-models with\nVillain and with cosine action. The method is based on a matching of the\nrenormalization group (RG) flow of the candidate models with the flow of a bona\nfide KT model, the exactly solvable BCSOS model. We obtain high precision\nestimates for the critical couplings and other non-universal quantities."
    },
    {
        "anchor": "The magnetized Gross-Neveu model at finite chemical potential: We study the (2+1)-dimensional Gross-Neveu model at non-zero chemical\npotential and subjected to a homogeneous background magnetic field. We do so\nboth analytically, in the limit of an infinite number of fermion flavors in\nwhich mean-field approaches become exact, as well as on the lattice for a\nsingle flavor. The rich and exotic phase structure observed in the mean-field\nlimit is found to be destroyed when strong quantum fluctuations are present in\nthe system. Instead, in the phase of spontaneously broken chiral symmetry the\nmagnetic field enhances this breaking for all choices of parameters. As a\nbyproduct, we find indications for a first-order phase transition in the\nchemical potential for vanishing magnetic field but also provide hints that\nthis could rather be a finite-size than a finite-flavor-number effect.",
        "positive": "Domain Wall Fermions for Planar Physics: In 2+1 dimensions, Dirac fermions in reducible, i.e. four-component\nrepresentations of the spinor algebra form the basis of many interesting model\nfield theories and effective descriptions of condensed matter phenomena. This\npaper explores lattice formulations which preserve the global U(2N ) symmetry\npresent in the massless limit, and its breakdown to U(N)xU(N) implemented by\nthree independent and parity-invariant fermion mass terms. I set out\ngeneralisations of the Ginsparg-Wilson relation, leading to a formulation of an\noverlap operator, and explore the remnants of the global symmetries which\ndepart from the continuum form by terms of order of the lattice spacing. I also\ndefine a domain wall formulation in 2+1+1d, and present numerical evidence, in\nthe form of bilinear condensate and meson correlator calculations in quenched\nnon-compact QED using reformulations of all three mass terms, to show that\nU(2N) symmetry is recovered in the limit that the domain-wall separation tends\nto infinity. The possibility that overlap and domain wall formulations of\nreducible fermions may coincide only in the continuum limit is discussed."
    },
    {
        "anchor": "Calculation of the $K_L-K_S$ mass difference for physical quark masses: In this article, I will present the status of our calculation of the\ndifference between the masses of the long- and short-lived neutral K mesons,\n$\\Delta m_K$ predicted by the Standard Model. This calculation is performed on\nan ensemble of 152, $64^3 \\times 128$ gauge configurations with an inverse\nlattice spacing of 2.36 GeV and physical quark masses. The results from\ndifferent methods of analysis and our progress toward obtaining a final result\nwill be discussed.",
        "positive": "$D$-meson semileptonic form factors at zero momentum transfer in\n  (2+1+1)-flavor lattice QCD: We present a calculation of the $D\\to K \\ell \\nu$ and $D\\to\\pi \\ell \\nu$\nsemileptonic form factors at $q^2=0$, which enable determinations of the CKM\nmatrix elements $\\lvert{V_{cs}}\\rvert$ and $\\lvert{V_{cd}}\\rvert$,\nrespectively. We use gauge-field configurations generated by the MILC\ncollaboration with four flavors of highly-improved staggered (HISQ) quarks,\nanalyzing several ensembles including those with physical pion masses and\napproximate lattice spacings ranging from 0.12~fm to 0.042~fm. We also use the\nHISQ action for the valence quarks. We employ twisted boundary conditions to\ncalculate the form factors at zero momentum transfer directly. We use\nheavy-light-meson chiral perturbation theory modified for energetic pions and\nkaons, and supplemented by terms to describe the lattice-spacing dependence, to\nobtain preliminary results at the physical point and in the continuum limit."
    },
    {
        "anchor": "Quadratically optimized polynomials for fermion simulations: Quadratically optimized polynomials are described which are useful in\nmulti-bosonic algorithms for Monte Carlo simulations of quantum field theories\nwith fermions. Algorithms for the computation of the coefficients and roots of\nthese polynomials are described and their implementation in the algebraic\nmanipulation language Maple is discussed. Tests of the evaluation of\npolynomials on dynamical fermion configurations are performed. In a simple\nspecial case the obtained polynomial approximations are compared to Chebyshev\npolynomials.",
        "positive": "Light hadron and diquark spectroscopy in quenched QCD with overlap\n  quarks on a large lattice: A simulation of quenched QCD with the overlap Dirac operator has been\ncompleted using 100 Wilson gauge configurations at beta = 6 on an 18^3 x 64\nlattice and at beta = 5.85 on a 14^3 x 48 lattice, both in Landau gauge. We\npresent results for light meson and baryon masses, meson final state \"wave\nfunctions,\" and other observables, as well as some details on the numerical\ntechniques that were used. Our results indicate that scaling violations, if\nany, are small. We also present an analysis of diquark correlations using the\nquark propagators generated in our simulation."
    },
    {
        "anchor": "Hadron Structure from Lattice QCD: The structure of neutrons, protons, and other strongly interacting particles\nis now being calculated in full, unquenched lattice QCD with quark masses\nentering the chiral regime. This talk describes selected examples, including\nthe nucleon axial charge, structure functions, electromagnetic form factors,\nthe origin of the nucleon spin, the transverse structure of the nucleon, and\nthe nucleon to Delta transition form factor.",
        "positive": "Wilson and Domainwall Kernels on Oakforest-PACS: We report the performance of Wilson and Domainwall Kernels on a new Intel\nXeon Phi Knights Landing based machine named Oakforest-PACS, which is co-hosted\nby University of Tokyo and Tsukuba University and is currently fastest in\nJapan. This machine uses Intel Omni-Path for the internode network. We compare\nperformance with several types of implementation including that makes use of\nthe Grid library. The code is incorporated with the code set Bridge++."
    },
    {
        "anchor": "Analytic Continuation in Two-color Finite Density QCD and Chiral Random\n  Matrix Model: Two-color finite density QCD is free from the sign problem, and it is thus\nregarded as a good model to check the validity of the analytic continuation\nmethod. We study the method in terms of the corresponding chiral random matrix\nmodel. It is found that at temperatures slightly higher than the pseudo\ncritical temperature, the ratio type of extrapolated function works well in\naccordance with the results of the Monte Carlo simulations.",
        "positive": "Charmed Meson Scattering from Lattice QCD: State-of-the-art lattice QCD calculations of scattering amplitudes in\ncoupled-channel $D\\pi$, $D\\eta$ and $D_{s}\\bar{K}$ scattering, as well elastic\n$DK$ scattering are discussed. The methodology employed allows a determination\nof the relevant poles in the scattering matrix, while also providing a measure\nof the coupling of each channel to a given pole. By investigating $S$, $P$ and\n$D$ wave interactions, the nature of states with $J^{P} = 0^{+}$, relevant for\nthe $D^{*}_{0}(2400)$ and $D^{*}_{s0}(2317)$, as well as states with $J^{P} =\n1^{-}, 2^{+}$ are discussed."
    },
    {
        "anchor": "The Paraldor Project: Paraldor is an experiment in bringing the power of categorical languages to\nlattice QCD computations. Our target language is Aldor, which allows the\ncapture of the mathematical structure of physics directly in the structure of\nthe code using the concepts of categories, domains and their\ninter-relationships in a way which is not otherwise possible with current\npopular languages such as Fortran, C, C++ or Java. By writing high level\nphysics code portably in Aldor, and implementing switchable machine dependent\nhigh performance back-ends in C or assembler, we gain all the power of\ncategorical languages such as modularity, portability, readability and\nefficiency.",
        "positive": "C-Periodicity and the Physical Mass in the 3-State Potts Model: The standard infinite-volume definition of connected correlation function and\nparticle mass in the 3-state Potts model can be implemented in Monte Carlo\nsimulations by using C-periodic spatial boundary conditions. This avoids both\nthe breaking of translation invariance (cold wall b.c.) and the phase-dependent\nand thus possibly biased evaluation of data (periodic boundary cconditions).\nThe numerical feasibility of the standard definitions is demonstrated by sample\ncomputations on a 24*24*48 lattice."
    },
    {
        "anchor": "Cooling study of Dirac sheets in SU(3) lattice gauge theory below T_c: Using a standard cooling method for SU(3) lattice gauge fields constant\nAbelian magnetic field configurations are extracted after dyon-antidyon\nconstituents forming metastable Q=0 configurations have annihilated. These\nso-called Dirac sheets, standard and non-standard ones, corresponding to the\ntwo U(1) subgroups of the SU(3) group, have been found to be stable if emerging\nfrom the confined phase, close to the deconfinement phase transition, with\nsufficiently nontrivial Polyakov loop values. On a finite lattice we find a\nnice agreement of the numerical observations with the analytic predictions\nconcerning the stability of Dirac sheets depending on the value of the Polyakov\nloop.",
        "positive": "The RHMC algorithm for theories with unknown spectral bounds: The Rational Hybrid Monte Carlo (RHMC) algorithm extends the Hybrid Monte\nCarlo algorithm for lattice QCD simulations to situations involving fractional\npowers of the determinant of the quadratic Dirac operator. This avoids the\nupdating increment ($dt$) dependence of observables which plagues the Hybrid\nMolecular-dynamics (HMD) method. The RHMC algorithm uses rational\napproximations to fractional powers of the quadratic Dirac operator. Such\napproximations are only available when positive upper and lower bounds to the\noperator's spectrum are known. We apply the RHMC algorithm to simulations of 2\ntheories for which a positive lower spectral bound is unknown: lattice QCD with\nstaggered quarks at finite isospin chemical potential and lattice QCD with\nmassless staggered quarks and chiral 4-fermion interactions ($\\chi$QCD). A\nchoice of lower bound is made in each case, and the properties of the RHMC\nsimulations these define are studied. Justification of our choices of lower\nbounds is made by comparing measurements with those from HMD simulations, and\nby comparing different choices of lower bounds."
    },
    {
        "anchor": "Up-, down-, strange-, charm-, and bottom-quark masses from four-flavor\n  lattice QCD: We calculate the up-, down-, strange-, charm-, and bottom-quark masses using\nthe MILC highly improved staggered-quark ensembles with four flavors of\ndynamical quarks. We use ensembles at six lattice spacings ranging from\n$a\\approx0.15$~fm to $0.03$~fm and with both physical and unphysical values of\nthe two light and the strange sea-quark masses. We use a new method based on\nheavy-quark effective theory (HQET) to extract quark masses from heavy-light\npseudoscalar meson masses. Combining our analysis with our separate\ndetermination of ratios of light-quark masses we present masses of the up,\ndown, strange, charm, and bottom quarks. Our results for the\n$\\overline{\\text{MS}}$-renormalized masses are $m_u(2~\\text{GeV}) =\n2.130(41)$~MeV, $m_d(2~\\text{GeV}) = 4.675(56)$~MeV, $m_s(2~\\text{GeV}) =\n92.47(69)$~MeV, $m_c(3~\\text{GeV}) = 983.7(5.6)$~MeV, and $m_c(m_c) =\n1273(10)$~MeV, with four active flavors; and $m_b(m_b) = 4195(14)$~MeV with\nfive active flavors. We also obtain ratios of quark masses $m_c/m_s =\n11.783(25)$, $m_b/m_s = 53.94(12)$, and $m_b/m_c = 4.578(8)$. The result for\n$m_c$ matches the precision of the most precise calculation to date, and the\nother masses and all quoted ratios are the most precise to date. Moreover,\nthese results are the first with a perturbative accuracy of $\\alpha_s^4$. As\nbyproducts of our method, we obtain the matrix elements of HQET operators with\ndimension 4 and 5: $\\overline{\\Lambda}_\\text{MRS}=555(31)$~MeV in the minimal\nrenormalon-subtracted (MRS) scheme, $\\mu_\\pi^2 = 0.05(22)~\\text{GeV}^2$, and\n$\\mu_G^2(m_b)=0.38(2)~\\text{GeV}^2$. The MRS scheme [Phys. Rev. D97, 034503\n(2018), arXiv:1712.04983 [hep-ph]] is the key new aspect of our method.",
        "positive": "A study of topological quantities of lattice QCD by a modified DCGAN\n  frame: A modified deep convolutional generative adversarial network (M-DCGAN) frame\nis proposed to study the N-dimensional (ND) topological quantities in lattice\nQCD based on the Monte Carlo (MC) simulations. We construct a new scaling\nstructure including fully connected layers to support the generation of\nhigh-quality high-dimensional images for the M-DCGAN. Our results show that the\nM-DCGAN scheme of the Machine learning should be helpful for us to calculate\nefficiently the 1D distribution of topological charge and the 4D topological\ncharge density compared with the case by the MC simulation alone."
    },
    {
        "anchor": "Large Field Cutoffs Make Perturbative Series Converge: For lambda phi^4 problems, convergent perturbative series can be obtained by\ncutting off the large field configurations. The modified series converge to\nvalues exponentially close to the exact ones. For lambda larger than some\ncritical value, the method outperforms Pade approximants and Borel summations.\nWe discuss some aspects of the semi-classical methods used to calculate the\nmodified Feynman rules and estimate the error associated with the procedure. We\nprovide a simple numerical example where the procedure works despite the fact\nthat the Borel sum has singularities on the positive real axis.",
        "positive": "Hausdorff dimension of fermions on a random lattice: Geometric properties of lattice quantum gravity in two dimensions are studied\nnumerically via Monte Carlo on Euclidean Dynamical Triangulations. A new\ncomputational method is proposed to simulate gravity coupled with fermions,\nwhich allows the study of interacting theories on a lattice, such as\nnon-Riemannian gravity models. This was tested on Majorana spinors, where we\nobtained a Hausdorff dimension dW = 4.22 +/- 0.03, consistent with the bounds\nfrom the literature 4.19 < dH < 4.21."
    },
    {
        "anchor": "Application of preconditioned block BiCGGR to the Wilson-Dirac equation\n  with multiple right-hand sides in lattice QCD: There exist two major problems in application of the conventional block\nBiCGSTAB method to the O(a)-improved Wilson-Dirac equation with multiple\nright-hand-sides: One is the deviation between the true and the recursive\nresiduals. The other is the convergence failure observed at smaller quark\nmasses for enlarged number of the right-hand-sides. The block BiCGGR algorithm\nwhich was recently proposed by the authors succeeds in solving the former\nproblem. In this article we show that a preconditioning technique allows us to\nimprove the convergence behavior for increasing number of the right-hand-sides.",
        "positive": "Chronological Inversion Method for the Dirac Matrix in Hybrid Monte\n  Carlo: In Hybrid Monte Carlo simulations for full QCD, the gauge fields evolve\nsmoothly as a function of Molecular Dynamics time. Here we investigate improved\nmethods of estimating the trial or starting solutions for the Dirac matrix\ninversion as superpositions of a chronological sequence of solutions in the\nrecent past. By taking as the trial solution the vector which minimizes the\nresidual in the linear space spanned by the past solutions, the number of\nconjugate gradient iterations per unit MD time is decreased by at least a\nfactor of 2. Extensions of this basic approach to precondition the conjugate\ngradient iterations are also discussed."
    },
    {
        "anchor": "Low-lying mode contribution to the quenched meson correlators in the\n  epsilon-regime: We present a quenched calculation of meson correlators with the overlap\nfermion at very small masses 2.6--13 MeV. In this region the pion Compton\nwavelength is larger than our lattice size L\\simeq 1.23fm and the system is in\nthe so-called epsilon-regime of chiral perturbation theory. We found that the\nscalar and pseudo-scalar correlators are precisely approximated by a few\nhundred low-lying fermion eigenmodes in this regime, whereas axial-vector\ncorrelator receives significant contributions from higher eigenmodes. We also\nmeasure the disconnected pseudo-scalar correlator, which is well saturated with\nthe low-lying modes. Matching these lattice data with the one-loop expressions\nfor the correlators in quenched chiral perturbation theory, we evaluate the\ndecay constant F_pi and the chiral condensate Sigma as well as the parameters\nm_0 and alpha, which describe the artifacts of the quenched approximation.",
        "positive": "Renormalization constants for one-derivative fermion operators in\n  twisted mass QCD: We present perturbative and non-perturbative results on the renormalization\nconstants of the local and one-derivative vector and axial vector operators.\nNon-perturbative results are obtained using the twistedmassWilson fermion\nformulation employing two degenerate dynamical quarks and the tree-level\nSymanzik improved gluon action for pion masses in the range of about 450-260\nMeV and at there values of the lattice spacing, namely 0.055 fm, 0.070 fm and\n0.089 fm. Subtraction of O(a^2) terms is carried out by performing the\nperturbative evaluation of these operators at 1- loop and up to O(a^2). The\nrenormalization conditions are defined in the RI'-MOM scheme, for both\nperturbative and non-perturbative results. The Z-factors, obtained for\ndifferent values of the renormalization scale, are evolved perturbatively to a\nreference scale set by the inverse of the lattice spacing. In addition, they\nare translated to MS-bar at 2 GeV using 3-loop perturbative results for the\nconversion factors."
    },
    {
        "anchor": "First results for SU(2) Yang-Mills with one adjoint Dirac Fermion: We present a first exploratory study of SU(2) gauge theory with one Dirac\nflavour in the adjoint representation. We provide initial results for the\nspectroscopy and the anomalous dimension for the chiral condensate. Our\ninvestigation indicates that the theory is conformal or near-conformal, with an\nanomalous dimension of order one. A discussion of the relevance of these\nfindings in relation to walking technicolor scenarios is also presented.",
        "positive": "Global obstructions to gauge-invariance in chiral gauge theory on the\n  lattice: It is shown that certain global obstructions to gauge-invariance in chiral\ngauge theory, described in the continuum by Alvarez-Gaume and Ginsparg, are\nexactly reproduced on the lattice in the Overlap formulation at small non-zero\nlattice spacing (i.e. close to the classical continuum limit). As a\nconsequence, the continuum anomaly cancellation condition $d_R^{abc}=0$ is seen\nto be a necessary (although not necessarily sufficient) condition for anomaly\ncancellation on the lattice in the Overlap formulation."
    },
    {
        "anchor": "Tuning the Hybrid Monte Carlo algorithm using molecular dynamics forces'\n  variances: Within the HMC algorithm, we discuss how, by using the shadow Hamiltonian and\nthe Poisson brackets, one can achieve a simple factorization in the dependence\nof the Hamiltonian violations upon either the algorithmic parameters or the\nparameters specifying the integrator. We consider the simplest case of a second\norder (nested) Omelyan integrator and one level of Hasenbusch splitting of the\ndeterminant for the simulations of a QCD-like theory (with gauge group SU(2)).\nGiven the specific choice of the integrator, the Poisson brackets reduce to the\nvariances of the molecular dynamics forces. We show how the factorization can\nbe used to optimize in a very economical and simple way both the algorithmic\nand the integrator parameters with good accuracy.",
        "positive": "The Non-Perturbative ${\\cal O}(g^6)$ Contribution to the Free Energy of\n  Hot SU(N) Gauge Theory: The non-perturbative input necessary for the determination of the ${\\cal\nO}(g^6)$ part of the weak coupling expansion of the free energy density for\nSU(2) and SU(3) gauge theories is estimated. Although the perturbative\ninformation completing the contribution to this order is missing, we give\narguments that the magnetic fluctuations are dominated by screened elementary\nmagnetic gluons."
    },
    {
        "anchor": "New insights into the problem with a singular drift term in the complex\n  Langevin method: The complex Langevin method aims at performing path integral with a complex\naction numerically based on complexification of the original real dynamical\nvariables. One of the poorly understood issues concerns occasional failure in\nthe presence of logarithmic singularities in the action, which appear, for\ninstance, from the fermion determinant in finite density QCD. We point out that\nthe failure should be attributed to the breakdown of the relation between the\ncomplex weight that satisfies the Fokker-Planck equation and the probability\ndistribution associated with the stochastic process. In fact, this problem can\noccur in general when the stochastic process involves a singular drift term. We\nshow, however, in a simple example that there exists a parameter region in\nwhich the method works although the standard reweighting method is hardly\napplicable.",
        "positive": "$b\\bar b u\\bar d$ four-quark systems in the Born-Oppenheimer\n  approximation: prospects and challenges: We summarize previous work on $\\bar b \\bar bud$ four-quark systems in the\nBorn-Oppenheimer approximation and discuss first steps towards an extension to\nthe theoretically more challenging $b\\bar b u\\bar d$ system. Strategies to\nidentify a possibly existing $b\\bar b u\\bar d$ bound state are discussed and\nfirst numerical results are presented."
    },
    {
        "anchor": "Z_2 Monopoles, Vortices and the Universality of the SU(2) Deconfinement\n  Transition: We investigate the effect of $Z_2$ magnetic monopoles and vortices on the\nfinite temperature deconfinement phase transition in the fundamental - adjoint\nSU(2) lattice gauge theory. In the limit of complete suppression of the $Z_2$\nmonopoles, the mixed action for the SU(2) theory in its Villain form is shown\nto be self-dual under the exchange of the fundamental and adjoint couplings. By\nfurther suppressing the $Z_2$ vortices we show that the extended model reduces\nto the Wilson action with a modified coupling. The universality of the SU(2)\ndeconfinement phase transition with the Ising model is therefore expected to\nremain intact in the entire plane of the fundamental-adjoint couplings in the\ncontinuum limit. The self-duality arguments related to the suppression of $Z_2$\nmonopoles are also applicable to the Villain form of mixed action for the SU(N)\ntheory with $Z_{N}$ magnetic monopoles.",
        "positive": "On the low fermionic eigenmode dominance in QCD on the lattice: We demonstrate the utility of a spectral approximation to fermion loop\noperators using low-lying eigenmodes of the hermitian Dirac-Wilson matrix, Q.\nThe investigation is based on a total of 400 full QCD vacuum configurations,\nwith two degenerate flavors of dynamical Wilson fermions at beta =5.6, at two\ndifferent sea quark masses. The spectral approach is highly competitive for\naccessing both topological charge and disconnected diagrams, on large lattices\nand small quark masses. We propose suitable partial summation techniques that\nprovide sufficient saturation for estimating Tr Q^{-1}, which is related to the\ntopological charge. In the effective mass plot of the eta' meson we achieved a\nconsistent early plateau formation, by ground state projecting the connected\npiece of its propagator."
    },
    {
        "anchor": "Non-Gaussian numerical errors versus mass hierarchy: We probe the numerical errors made in renormalization group calculations by\nvarying slightly the rescaling factor of the fields and rescaling back in order\nto get the same (if there were no round-off errors) zero momentum 2-point\nfunction (magnetic susceptibility). The actual calculations were performed with\nDyson's hierarchical model and a simplified version of it. We compare the\ndistributions of numerical values obtained from a large sample of rescaling\nfactors with the (Gaussian by design) distribution of a random number generator\nand find significant departures from the Gaussian behavior. In addition, the\naverage value differ (robustly) from the exact answer by a quantity which is of\nthe same order as the standard deviation. We provide a simple model in which\nthe errors made at shorter distance have a larger weight than those made at\nlarger distance. This model explains in part the non-Gaussian features and why\nthe central-limit theorem does not apply.",
        "positive": "Improved Currents for Heavy Quarks: We discuss lattice artifacts for matrix elements of hadrons containing one or\nmore heavy quark. In particular, we analyze interrelations between lattice\nartifacts and the $1/m_Q$ expansion. The implications for calculations of\nheavy-light decay constants and of semi-leptonic form factors are discussed."
    },
    {
        "anchor": "Testing a new method for scattering in finite volume in the $\u03c6^4$\n  theory: We test an alternative proposal by Bruno and Hansen [1] to extract the\nscattering length from lattice simulations in a finite volume. For this, we use\na scalar $\\phi^4$ theory with two mass nondegenerate particles and explore\nvarious strategies to implement this new method. We find that the results are\ncomparable to those obtained from the L\\\"uscher method, with somewhat smaller\nstatistical uncertainties at larger volumes.",
        "positive": "A smoother approach to scaling by suppressing monopoles and vortices: Suppressing monopoles and vortices by introducing large chemical potentials\nfor them in the Wilson action for the SU(2) lattice gauge theory, we study the\nnature of the deconfinement phase transition on N_sigma^3 X N_tau lattices for\nN_tau =4, 5, 6 and 8 and N_sigma = 8-16. Using finite size scaling theory, we\nobtain \\omega = 1.93 +/- 0.03 for N_tau = 4, in excellent agreement with\nuniversality. The critical couplings for N_tau= 4, 5, 6 and 8 lattices exhibit\nlarge shifts towards the strong coupling region when compared with the usual\nWilson action, and suggest a lot smoother approach to scaling."
    },
    {
        "anchor": "Lattice determination of $I= 0$ and 2 $\u03c0\u03c0$ scattering phase shifts\n  with a physical pion mass: Phase shifts for $s$-wave $\\pi\\pi$ scattering in both the $I=0$ and $I=2$\nchannels are determined from a lattice QCD calculation performed on 741 gauge\nconfigurations obeying G-parity boundary conditions with a physical pion mass\nand lattice size of $32^3\\times 64$. These results support our recent study of\ndirect CP violation in $K\\to\\pi\\pi$ decay \\cite{Abbott:2020hxn}, improving our\nearlier 2015 calculation \\cite{Bai:2015nea}. The phase shifts are determined\nfor both stationary and moving $\\pi\\pi$ systems, at three ($I=0$) and four\n($I=2$) different total momenta. We implement several $\\pi\\pi$ interpolating\noperators including a scalar bilinear \"$\\sigma$\" operator and paired\nsingle-pion bilinear operators with the constituent pions carrying various\nrelative momenta. Several techniques, including correlated fitting and a\nbootstrap determination of p-values have been used to refine the results and a\ncomparison with the generalized eigenvalue problem (GEVP) method is given. A\ndetailed systematic error analysis is performed which allows phase shift\nresults to be presented at a fixed energy.",
        "positive": "Taste non-Goldstone, flavor-charged pseudo-Goldstone boson masses in\n  staggered chiral perturbation theory: We calculate the masses of taste non-Goldstone pions and kaons in staggered\nchiral perturbation theory through next-to-leading order in the standard power\ncounting. The results can be used to quantitatively understand taste violations\nin existing lattice data generated with staggered fermions and to extract the\n$u$, $d$, and $s$ quark masses and Gasser-Leutwyler parameters from the\nexperimentally observed spectrum. The expressions for the non-Goldstone masses\ncontain low-energy couplings unique to the non-Goldstone sector. With two\nexceptions these enter as coefficients of analytic terms; all the new couplings\ncan be fixed by performing spectrum calculations. We report one-loop results\nfor the quenched case and the fully dynamical and partially quenched 1+1+1 and\n2+1 flavor cases in the chiral SU(3) and SU(2) theories."
    },
    {
        "anchor": "Pseudoscalar decay constants of kaon and D-mesons from Nf=2 twisted mass\n  Lattice QCD: We present the results of a lattice QCD calculation of the pseudoscalar meson\ndecay constants fpi, fK, fD and fDs, performed with Nf=2 dynamical fermions.\nThe simulation is carried out with the tree-level improved Symanzik gauge\naction and with the twisted mass fermionic action at maximal twist. We have\nconsidered for the final analysis three values of the lattice spacing, a~0.10\nfm, 0.09 fm and 0.07 fm, with pion masses down to mpi~270 MeV. Our results for\nthe light meson decay constants are fK=158.1(2.4) MeV and fK/fpi=1.210(18).\n  From the latter ratio, by using the experimental determination of\nGamma(K-->mu nu_mu (gamma))/ Gamma(pi--> mu nu_mu (gamma)) and the average\nvalue of |Vud| from nuclear beta decays, we obtain |Vus|=0.2222(34), in good\nagreement with the determination from semileptonic Kl3 decays and the unitarity\nconstraint. For the D and Ds meson decay constants we obtain fD=197(9) MeV,\nfDs=244(8) MeV and fDs/fD=1.24(3). Our result for fD is in good agreement with\nthe CLEO experimental measurement. For fDs our determination is smaller than\nthe PDG 2008 experimental average but in agreement with a recent improved\nmeasurement by CLEO at the 1.4 sigma level.",
        "positive": "Study of shear viscosity of SU (2)-gluodynamics within lattice\n  simulation: This paper is devoted to the study of two-point correlation function of the\nenergy-momentum tensor T_{12}T_{12} for SU(2)-gluodynamics within lattice\nsimulation of QCD. Using multilevel algorithm we carried out the measurement of\nthe correlation function at the temperature T/T_c = 1.2. It is shown that\nlattice data can be described by spectral functions which interpolate between\nhydrodynamics at low frequencies and asymptotic freedom at high frequencies.\nThe results of the study of spectral functions allowed us to estimate the ratio\nof shear viscosity to the entropy density {\\eta}/s = 0.134 +- 0.057."
    },
    {
        "anchor": "One-loop matching of Delta S=2 four-quark operators with improved\n  staggered fermions: We compute O(alpha_s) lattice-to-continuum perturbative matching coefficients\nfor the Delta S=2 flavor changing four-quark operators for the Asqtad improved\nstaggered action. In conjunction with lattice simulations with three flavors of\nlight, dynamical quarks, our results yield an unquenched determination of B_K,\nthe parameter that determines the amount of indirect CP violation in the\nneutral kaon system. Its value is an important input for the unitarity triangle\nanalysis of weak decays.",
        "positive": "Riemannian Manifold HMC with fermions: We report on our study of the Riemannian Manifold HMC (RMHMC) algorithm with\nthe mass term for the gauge momenta replaced by rational functions of the gauge\ncovariant Laplace operator. A comparison of HMC and RMHMC on a 2+1+1 flavor\ndynamical ensemble with lattice spacing a ~0.05fm shows increased rate of\nchange in long distance modes, identified by Wilson flowed energy, per fermion\nmolecular dynamics step."
    },
    {
        "anchor": "QCD thermodynamics with two flavours of Wilson fermions on large\n  lattices: We explore the phase diagram of two flavour QCD at vanishing chemical\npotential using dynamical O(a)-improved Wilson quarks. In the approach to the\nchiral limit we use lattices with a temporal extent of N_t=16 and spatial\nextent L=32,48 and 64 to enable the extrapolation to the thermodynamic limit\nwith small discretisation effects. In addition to an update on the scans at\nconstant \\kappa, reported earlier, we present first results from scans along\nlines of constant physics at a pion mass of 290 MeV. We probe the transition\nusing the Polyakov loop and the chiral condensate, as well as spectroscopic\nobservables such as screening masses.",
        "positive": "A Lattice Calculation of the Isgur-Wise Function: We calculate the Isgur-Wise function ($\\xi_0$) by measuring the heavy-heavy\nmeson transition matrix element on the lattice in the quenched approximation.\nThe standard Wilson action is used for both the heavy and the light quarks. Our\nnumerical results are compared with various model calculations and experimental\ndata. In particular, using a linear fit, we find $\\rho^2 = 1.24\\pm .26 \\pm .26\n$. (The slope of $\\xi_0$ at the zero-recoil point is $-\\rho^2$.) Using instead\nthe parametrization of $\\xi_0$ suggested by Neubert and Rieckert and fitting\nthe lattice data up to $v\\cdot v' \\sim 1.2$, we find\n$\\rho^2_{NR}=1.41\\pm.19\\pm.19$"
    },
    {
        "anchor": "Lattice QCD Simulations in External Background Fields: We discuss recent results and future prospects regarding the investigation,\nby lattice simulations, of the non-perturbative properties of QCD and of its\nphase diagram in presence of magnetic or chromomagnetic background fields.\nAfter a brief introduction to the formulation of lattice QCD in presence of\nexternal fields, we focus on studies regarding the effects of external fields\non chiral symmetry breaking, on its restoration at finite temperature and on\ndeconfinement. We conclude with a few comments regarding the effects of\nelectromagnetic background fields on gluodynamics.",
        "positive": "Heavy Quarkonia beyond Deconfinement and Real Time Lattice Simulations: Since the initial investigation by Matsui and Satz heavy quark bound states\nat finite temperature have been subject to numerous studies. The derivation of\na finite-temperature potential from first principles was attempted only\nrecently however, by generalising the Schroedinger equation which is\nsuccessfully employed for the description of quarkonia at zero temperature to a\nthermal setting. In this note the finite-temperature static potential is\nderived to leading order using resummed perturbation theory. The modification\nof the heavy quarkonium spectral function by an imaginary part of the potential\nappearing at finite temperature is discussed. Additionally, the extent of\npossible corrections due to non-perturbative processes is assessed by employing\nreal-time lattice techniques based on kinetic theory."
    },
    {
        "anchor": "Excited spectroscopy of mesons containing charm quarks from lattice QCD: We present highly excited spectra of charmonium, charm-light and\ncharm-strange mesons using the dynamical anisotropic lattices of the Hadron\nSpectrum Collaboration. The use of novel techniques has allowed us to extract\nthese spectra with a high degree of statistical precision, while also enabling\nus to observe states as high as spin-4, states with exotic quantum numbers and\ncandidate gluonic excitations. We discuss the phenomenology of these spectra,\nand also present preliminary results of D{\\pi} scattering considering only the\nlowest partial wave in the isospin-3/2 channel.",
        "positive": "Four-quark flux distribution and binding in lattice SU(2): The full spatial distribution of the color fields of two and four static\nquarks is measured in lattice SU(2) field theory at separations up to 1 fm at\nbeta=2.4. The four-quark case is equivalent to a qbar q qbar q system in SU(2)\nand is relevant to meson-meson interactions. By subtracting two-body flux tubes\nfrom the four-quark distribution we isolate the flux contribution connected\nwith the four-body binding energy. This contribution is further studied using a\nmodel for the binding energies. Lattice sum rules for two and four quarks are\nused to verify the results."
    },
    {
        "anchor": "Nucleon Helicity Generalized Parton Distribution at Physical Pion Mass\n  from Lattice QCD: The generalized parton distributions (GPDs) offer a window on\nthree-dimensional imaging of the nucleon, providing understanding of how the\nfundamental properties of the nucleon, such as its mass and spin, arise from\nthe underlying quark and gluon degrees of freedom. In this work, we present the\nfirst lattice calculation of the nucleon isovector helicity GPD at physical\npion mass, using an $a \\approx 0.09$ fm lattice ensemble with 2+1+1 flavors of\nhighly improved staggered quarks generated by MILC Collaboration. We perform\nthe GPD calculation in Breit frame using averaged nucleon boost momentum $P_z\n\\approx 2.2$ GeV with nonzero momentum transfers in $[0.2,1.0]\\text{ GeV}^2$.\nNonperturbative renormalization in RI/MOM scheme is used to obtain the\nquasi-distribution before matching to the lightcone GPDs. The three-dimensional\ndistribution $\\tilde{H}(x,Q^2)$ is presented, along with the three-dimensional\nnucleon tomography and impact-parameter--dependent distribution for selected\nBjorken $x$ at $\\mu=3$ GeV in $\\overline{\\text{MS}}$ scheme.",
        "positive": "Exploring the Dynamics of Three-Dimensional Lattice Gauge Theories by\n  External Fields: We investigate the dynamics of three-dimensional lattice gauge theories by\nmeans of an external Abelian magnetic field. For the SU(2) lattice gauge theory\nwe find evidence of the unstable modes."
    },
    {
        "anchor": "Dynamical determination of B_K from improved staggered quarks: The scaling corrections that affected previous staggered calculations of B_K\nhave been proved to be reduced by using improved actions (HYP, Asqtad) in the\nquenched approximation. This improved behaviour allows us to perform a reliable\ndynamical calculation of B_K including quark vacuum polarization effects using\nthe MILC (2+1) flavour dynamical configurations. We report here on the results\nfrom such dynamical calculation. We also discuss the renormalization effects\nwith the Asqtad action.",
        "positive": "Systematics of the HAL QCD Potential at Low Energies in Lattice QCD: The $\\Xi\\Xi$ interaction in the $^1$S$_0$ channel is studied to examine the\nconvergence of the derivative expansion of the non-local HAL QCD potential at\nthe next-to-next-to-leading order (N$^2$LO). We find that (i) the leading order\npotential from the N$^2$LO analysis gives the scattering phase shifts\naccurately at low energies, (ii) the full N$^2$LO potential gives only small\ncorrection to the phase shifts even at higher energies below the inelastic\nthreshold, and (iii) the potential determined from the wall quark source at the\nleading order analysis agrees with the one at the N$^2$LO analysis except at\nshort distances, and thus, it gives correct phase shifts at low energies. We\nalso study the possible systematic uncertainties in the HAL QCD potential such\nas the inelastic state contaminations and the finite volume artifact for the\npotential and find that they are well under control for this particular system."
    },
    {
        "anchor": "Correlation Functions and Confinement in Scalar QCD: The complete knowledge of a theory is encoded in its correlation functions.\nThus non-perturbative effects, like confinement in QCD, is necessarily\ncontained in these correlation functions. As a consequence, a number of\nconfinement scenarios make predictions for the behavior of these correlation\nfunctions. Non-perturbative methods, like lattice calculations, permit to\ncalculate the correlation functions and test these predictions. To avoid the\nentanglement with chiral symmetry breaking and the costs of full fermion\nsimulations, here scalar QCD will be used as a role model, as it is expected\nthat confinement operates in the same way. We present results on both two-point\nfunctions and three-point functions for the case of two colors and two flavors\nof scalars, and compare them to the predictions.",
        "positive": "The Z3 model with the density of states method: In this contribution we apply a new variant of the density of states method\nto the Z3 spin model at finite density. We use restricted expectation values\nevaluated with Monte Carlo simulations and study their dependence on a control\nparameter lambda. We show that a sequence of one-parameter fits to the\nMonte-Carlo data as a function of lambda is sufficient to completely determine\nthe density of states. We expect that this method has smaller statistical\nerrors than other approaches since all generated Monte Carlo data are used in\nthe determination of the density. We compare results for magnetization and\nsusceptibility to a reference simulation in the dual representation of the Z3\nspin model and find good agreement for a wide range of parameters."
    },
    {
        "anchor": "Phase Transition in the Two Dimensional Classical XY Model: For the two dimensional classical XY model we present extensive high\n-temperature -phase bulk data extracted based on a novel finite size scaling\n(FSS) Monte Carlo technique, along with FSS data near criticality. Our data\nverify that $\\eta=1/4$ sets in near criticality, and clarify the nature of\ncorrection to the leading scaling behavior. However, the result of standard FSS\nanalysis near criticality is inconsistent with other predictions of\nKosterlitz's renormalization group approach.",
        "positive": "Finite isospin density probe for conformality: A new method of employing an isospin chemical potential for QCD-like theories\nwith different number of colors, number of fermion flavors, and in different\nfermion representations is proposed. The isospin chemical potential, which can\nbe simulated on the lattice due to its positive definite determinant gives a\nmeans to probe both confining theories and IR conformal theories without\nadjusting the lattice spacing and size. As the quark mass is reduced, the\nisospin chemical potential provides an avenue to extract the chiral condensate\nin confining theories through the resulting pseudoscalar condensate. For IR\nconformal theories, the mass anomalous dimension can be extracted in the\nconformal window through \"finite density\" scaling since the isospin chemical\npotential is coupled to a conserved current. In both of these approaches, the\nisospin chemical potential can be continuously varied for each ensemble at\ncomparable costs while maintaining the hierarchy between the lattice size and\nlattice spacing. In addition to exploring these methods, finite volume and\nlattice spacing effects are investigated."
    },
    {
        "anchor": "Laplacian modes for calorons and as a filter: We compute low-lying eigenmodes of the gauge covariant Laplace operator on\nthe lattice at finite temperature. For classical configurations we show how the\nlowest mode localizes the monopole constituents inside calorons and that it\nhops upon changing the boundary conditions. The latter effect we observe for\nthermalized backgrounds, too, analogously to what is known for fermion zero\nmodes. We propose a new filter for equilibrium configurations which provides\nlink variables as a truncated sum involving the Laplacian modes. This method\nnot only reproduces classical structures, but also preserves the confining\npotential, even when only a few modes are used.",
        "positive": "Gluons in charmoniumlike states: The mass components of charmoniumlike states are investigated through the\ndecomposition of QCD energy-momentum tensor (EMT) on lattice. The quark mass\ncontribution $\\langle H_m\\rangle$ and the momentum fraction $\\langle x\\rangle$\nof valence charm quark and antiquark are calculated for conventional $1S,1P,1D$\ncharmonia and the exotic $1^{-+}$ charmoniumlike state, based on the $N_f=2+1$\ngauge configurations generated by the RBC/UKQCD collaboration. It is found that\n$\\langle H_m\\rangle$ is close to each other and around 2.0 to 2.2 GeV for these\nstates, which implies that the mass splittings among these states come almost\nfrom the gluon contribution of QCD trace anomaly. The $\\langle x\\rangle$ of the\n$1^{-+}$ state is only around 0.55, while that in conventional charmonia is\naround 0.7 to 0.8. This difference manifests that the proportion of light\nquarks and gluons in the $1^{-+}$ charmoniumlike state is significantly larger\nthan conventional states."
    },
    {
        "anchor": "Baryon magnetic moments in the external field method: We present a calculation of the magnetic moments of the baryon octet and\ndecuplet using the external field method and standard Wilson gauge and fermion\nactions in the quenched approximation. Progressively smaller static magnetic\nfields are introduced on a $24^4$ latticeat beta=6.0 and the pion mass is\nprobed down to about 500 MeV. Magnetic moments are extracted from the linear\nresponse of the masses to the external field.",
        "positive": "Running coupling in SU(2) with adjoint fermions: We present a measurement of the Schr\\\"odinger Functional running coupling in\nSU(2) lattice gauge theory with adjoint fermions. We use HEX smearing and\nclover improvement to reduce the discretization effects. We obtain a robust\ncontinuum limit for the step scaling, which confirms the existence of a\nnon-trivial fixed point."
    },
    {
        "anchor": "Sign problems, noise, and chiral symmetry breaking in a QCD-like theory: The Nambu-Jona-Lasinio model reduced to 2+1 dimensions has two different path\nintegral formulations: at finite chemical potential one formulation has a\nsevere sign problem similar to that found in QCD, while the other does not. At\nlarge N, where N is the number of flavors, one can compute the probability\ndistributions of fermion correlators analytically in both formulations. In the\nformer case one finds a broad distribution with small mean; in the latter one\nfinds a heavy tailed positive distribution amenable to the cumulant expansion\ntechniques developed in earlier work. We speculate on the implications of this\nmodel for QCD.",
        "positive": "Baryon masses with dynamical twisted mass fermions: We present results on the mass of the nucleon and the $\\Delta$ using two\ndynamical degenerate twisted mass quarks. The evaluation is performed at four\nquark masses corresponding to a pion mass in the range of 690-300 MeV on\nlattices of size 2.1 fm and 2.7 fm. We check for cutoff effects by evaluating\nthese baryon masses on lattices of spatial size 2.1 fm with lattice spacings\n$a(\\beta=3.9)=0.0855(6)$ fm and $a(\\beta=4.05)=0.0666(6)$ fm, determined from\nthe pion sector and find them to be within our statistical errors. Lattice\nresults are extrapolated to the physical limit using continuum chiral\nperturbation theory.\n  The nucleon mass at the physical point provides a determination of the\nlattice spacing. Using heavy baryon chiral perturbation theory at ${\\cal\nO}(p^3)$ we find $a(\\beta=3.9)=0.0879(12)$ fm, with a systematic error due to\nthe chiral extrapolation estimated to be about the same as the statistical\nerror. This value of the lattice spacing is in good agreement with the value\ndetermined from the pion sector. We check for isospin breaking in the\n$\\Delta$-system. We find that $\\Delta^{++,-}$ and $\\Delta^{+,0}$ are almost\ndegenerate pointing to small flavor violating effects."
    },
    {
        "anchor": "Strong-Isospin Breaking in the Neutron-Proton Mass Difference: We determine the strong-isospin violating component of the neutron-proton\nmass difference from fully-dynamical lattice QCD and partially-quenched QCD\ncalculations of the nucleon mass, constrained by partially-quenched chiral\nperturbation theory at one-loop level. The lattice calculations were performed\nwith domain-wall valence quarks on MILC lattices with rooted staggered\nsea-quarks at a lattice spacing of b ~ 0.125 fm, lattice spatial size of L~2.5\nfm and pion masses ranging from m_pi~290 MeV to ~350 MeV. At the physical value\nof the pion mass, we predict M_n - M_p |(d-u) = 2.26 +- 0.57 +- 0.42 +- 0.10\nMeV where the first error is statistical, the second error is due to the\nuncertainty in the ratio of light-quark masses, eta=m_u/m_d, determined by\nMILC, and the third error is an estimate of the systematic due to chiral\nextrapolation.",
        "positive": "Lattice regularizations of $\u03b8$ vacua: Anomalies and qubit models: Anomalies are a powerful way to gain insight into possible lattice\nregularizations of a quantum field theory. In this work, we argue that the\ncontinuum anomaly for a given symmetry can be matched by a\nmanifestly-symmetric, local, lattice regularization in the same spacetime\ndimensionality only if (i) the symmetry action is offsite, or (ii) if the\ncontinuum anomaly is reproduced exactly on the lattice. We consider lattice\nregularizations of a class of prototype models of QCD: the (1+1)-dimensional\nasymptotically-free Grassmannian nonlinear sigma models (NLSMs) with a $\\theta$\nterm. Using the Grassmannian NLSMs as a case study, we provide examples of\nlattice regularizations in which both possibilities are realized. For\npossibility (i), we argue that Grassmannian NLSMs can be obtained from\n$\\mathrm{SU}(N)$ antiferromagnets with a well-defined continuum limit,\nreproducing both the infrared physics of $\\theta$ vacua and the ultraviolet\nphysics of asymptotic freedom. These results enable the application of new\nclassical algorithms to lattice Monte Carlo studies of these quantum field\ntheories, and provide a viable realization suited for their quantum simulation.\nOn the other hand, we show that, perhaps surprisingly, the conventional lattice\nregularization of $\\theta$ vacua due to Berg and L\\\"uscher reproduces the\nanomaly exactly on the lattice, providing a realization of the second\npossibility."
    },
    {
        "anchor": "Fast Krylov Space Methods for Calculation of Quark Propogator: Different recently developed Krylov space methods for solving linear systems\nare studied and compared for the solution of the Dirac equation on the lattice.\nStabilized Biconjugate Gradient (BiCGstab2) is shown to be a robust and\nefficient solver for the calculation of the Wilson quark propagator in lattice\nQCD.",
        "positive": "Polyakov line actions from $SU(3)$ lattice gauge theory with dynamical\n  fermions: first results via relative weights: We apply the relative weights method to extract an effective Polyakov line\naction, at finite chemical potential, from an underlying $SU(3)$ lattice gauge\ntheory with dynamical fermions. The center-symmetry breaking terms in the\neffective theory are fit to a form suggested by the hopping-parameter\nexpansion, and the effective action is solved at finite chemical potential by a\nmean field approach. We present preliminary results for one-link staggered\nfermions with mass $ma=1.0$ and Wilson gauge action at $\\beta=5.4$ on\n$L^3\\times4$ lattices with $L=16$."
    },
    {
        "anchor": "Domain-wall fermions with $U(1)$ dynamical gauge fields: We have carried out a numerical simulation of a domain-wall model in\n$(2+1)$-dimensions, in the presence of a dynamical gauge field only in an extra\ndimension, corresponding to the weak coupling limit of a ( 2-dimensional )\nphysical gauge coupling. Using a quenched approximation we have investigated\nthis model at $\\beta_{s} ( = 1 / g^{2}_{s} ) =$ 0.5 ( ``symmetric'' phase),\n1.0, and 5.0 (``broken'' phase), where $g_s$ is the gauge coupling constant of\nthe extra dimension. We have found that there exists a critical value of a\ndomain-wall mass $m_{0}^{c}$ which separates a region with a fermionic zero\nmode on the domain-wall from the one without it, in both symmetric and broken\nphases. This result suggests that the domain-wall method may work for the\nconstruction of lattice chiral gauge theories.",
        "positive": "Double parton distributions with flavor interference from lattice QCD: We study double parton distributions with flavor interference in the nucleon\nand compare them with previous results for the flavor diagonal case. We\ninvestigate both unpolarized and polarized partons, and we compare our lattice\nresults with those obtained from the simple description of the proton in terms\nof an SU(6) symmetric three-quark wave function."
    },
    {
        "anchor": "Finite temperature study of the axial U(1) symmetry on the lattice with\n  overlap fermion formulation: We examine the axial U(1) symmetry near and above the finite temperature\nphase transition in two-flavor QCD using lattice QCD simulations. Although the\naxial U(1) symmetry is always violated by quantization, (i.e.) the chiral\nanomaly, the correlation functions may manifest effective restoration of the\nsymmetry in the high temperature phase. We explicitly study this possibility by\ncalculating the meson correlators as well as the Dirac operator spectral\ndensity near the critical point. Our numerical simulations are performed on a\n$16^3\\times 8$ lattice with two flavors of dynamical quarks represented by the\noverlap fermion formalism. Chiral symmetry and its violation due to the axial\nanomaly is manifestly realized with this formulation, which is a prerequisite\nfor the study of the effective restoration of the axial U(1) symmetry. In order\nto avoid discontinuity in the gauge configuration space, which occurs for the\nexactly chiral lattice fermions, the simulation is confined in a fixed\ntopological sector. It induces finite volume effect, which is well described by\na formula based on the Fourier transform from the $\\theta$-vacua. We confirm\nthis formula at finite temperature by calculating the topological\nsusceptibility in the quenched theory. Our two flavor simulations show\ndegeneracy of the meson correlators and a gap in the Dirac operator spectral\ndensity, which implies that the axial U(1) symmetry is effectively restored in\nthe chirally symmetric phase.",
        "positive": "Progress in Gauge-Higgs Unification on the Lattice: We study a five-dimensional pure SU(2) gauge theory formulated on the\norbifold and discretized on the lattice by means of Monte Carlo simulations.\nThe gauge symmetry is explicitly broken to U(1) at the orbifold boundaries. The\naction is the Wilson plaquette action with a modified weight for the boundary\nU(1) plaquettes. We study the phase transition and present results for the\nspectrum and the shape of the static potential on the boundary. The latter is\nsensitive to the presence of a massive Z-boson, in good agreement with the\ndirectly measured Z-boson mass. The results may support an alternative view of\nthe lattice orbifold (stemming from its mean-field study) as a 5d bosonic\nsuperconductor."
    },
    {
        "anchor": "RI/MOM Renormalization Window and Goldstone Pole Contamination: We perform a comparative study of the ratio of lattice (Wilson fermion)\nrenormalization constants Z_P/Z_S, obtained non-perturbatively from the RI/MOM\nrenormalization conditions and from Ward Identities of on- and off-shell\nGreen's functions. The off-shell Ward Identity used in this work relies on\ncorrelation functions with non-degenerate quark masses. We find that, due to\ndiscretization effects, there is a 10-15% discrepancy between the two Ward\nIdentity determinations at current bare couplings (beta values). The RI/MOM\nresult is in the same range and has a similar systematic error of 10-15%. Thus,\ncontrary to a previous claim, the contamination of the RI/MOM result from the\npresence of a Goldstone pole at scales of about 2 GeV is subdominant, compared\nto finite cutoff effects.",
        "positive": "Dynamical Chirally Improved Quarks: First Results for Hadron Masses: We present first results for a study with two mass-degenerate dynamical\nChirally Improved (CI) fermions on lattices of spatial extent 2.4 fm. The CI\nDirac operator obeys the Ginsparg-Wilson condition in good approximation. The\npion mass we use is still large O(470 MeV) for the 16**3*32 lattices with\nlattice spacing of 0.15 fm. The hadron masses are obtained with the variational\ntechnique and the results compared with earlier quenched calculations with\nsimilar lattice parameters. We find indications for the isovector, scalar meson\na0(980) near the experimental value, in contradistinction to quenched results\nwhich always produced a mass value compatible with the first excitation\na0(1450)."
    },
    {
        "anchor": "More methods for calculating the topological charge (density) of SU(N)\n  lattice gauge fields in 3+1 dimensions: We revisit old ideas that smearing or blocking an SU(N) lattice gauge field,\nor averaging over an ensemble of fields created in the neighbourhood of that\nfield, can reduce the high frequency fluctuations sufficiently that the naive\nlattice operator for the topological charge density is able to provide a\nreliable measure of the topological charge of the field. We show that these\nthree methods do indeed provide additional simple methods for calculating the\ntotal topological charge, with smearing particularly economical at current\ncouplings. More interestingly, the ensemble average method can also be used to\nexpose the distribution in space-time of the topological charge and this\nconceptually transparent, albeit computationally expensive, method provides a\nuseful benchmark against which to compare other methods. Using this benchmark\nwe find that a few smearing steps are also reliable in exposing the\ndistribution in space-time of the topological charge, thus providing a very\neconomical and simple method for doing so. We also use the same benchmark to\ndetermine what is the number of `cooling' sweeps one needs to perform in order\nto expose the charge density reliably.",
        "positive": "Searching for low-lying multi-particle thresholds in lattice\n  spectroscopy: We explore the Euclidean-time tails of odd-parity nucleon correlation\nfunctions in a search for the S-wave pion-nucleon scattering-state threshold\ncontribution. The analysis is performed using 2+1 flavor 32^3 x 64 PACS-CS\ngauge configurations available via the ILDG. Correlation matrices composed with\nvarious levels of fermion source/sink smearing are used to project low-lying\nstates. The consideration of 25,600 fermion propagators reveals the presence of\nmore than one state in what would normally be regarded as an\neigenstate-projected correlation function. This observation is in accord with\nthe scenario where the eigenstates contain a strong mixing of single and\nmulti-particle states but only the single particle component has a strong\ncoupling to the interpolating field. Employing a two-exponential fit to the\neigenvector-projected correlation function, we are able to confirm the presence\nof two eigenstates. The lower-lying eigenstate is consistent with a N-pi\nscattering threshold and has a relatively small coupling to the three-quark\ninterpolating field. We discuss the impact of this small scattering-state\ncontamination in the eigenvector projected correlation function on previous\nresults presented in the literature."
    },
    {
        "anchor": "Performance of Complex Langevin Simulation in 0+1 dimensional massive\n  Thirring model at finite density: Statistical sampling with the complex Langevin (CL) equation is applied to\n(0+1)-dimensional Thirring model, and its uniform-field variant, at finite\nfermion chemical potential $\\mu$. The CL simulation reproduces a crossover\nbehavior which is similar to but actually deviating from the exact solution in\nthe transition region, where we confirm that the CL simulation becomes\nsusceptible to the drift singularities, i.e., zeros of the fermion determinant.\nIn order to simulate the transition region with the CL method correctly, we\nexamine two approaches, a reweighting method and a model deformation, in both\nof which a single thimble with an attractive fixed point practically covers the\nintegration domain and the CL sampling avoids the determinant zeros. It turns\nout that these methods can reproduce the correct crossover behavior of the\noriginal model with using reference ensembles in the complexified space.\nHowever, they need evaluation of the reweighting factor, which scales with the\nsystem size exponentially. We discuss feasibility of applying these methods to\nthe Thirring model and to more realistic theories.",
        "positive": "Numerical properties of staggered overlap fermions: We report the results of a numerical study of staggered overlap fermions,\nfollowing the construction of Adams which reduces the number of tastes from 4\nto 2 without fine-tuning. We study the sensitivity of the operator to the\ntopology of the gauge field, its locality and its robustness to fluctuations of\nthe gauge field. We make a first estimate of the computing cost of a quark\npropagator calculation, and compare with Neuberger's overlap."
    },
    {
        "anchor": "Baryon structure from Lattice QCD: We present recent lattice results on the baryon spectrum, nucleon\nelectromagnetic and axial form factors, nucleon to $\\Delta$ transition form\nfactors as well as the $\\Delta$ electromagnetic form factors. The masses of the\nlow lying baryons and the nucleon form factors are calculated using two\ndegenerate flavors of twisted mass fermions down to pion mass of about 270 MeV.\nWe compare to the results of other collaborations. The nucleon to $\\Delta$\ntransition and $\\Delta$ form factors are calculated in a hybrid scheme, which\nuses staggered sea quarks and domain wall valence quarks. The dominant dipole\nnucleon to $\\Delta$ transition form factor is also evaluated using dynamical\ndomain wall fermions. The transverse density distributions of the $\\Delta$ in\nthe infinite momentum frame are extracted using the form factors determined\nfrom lattice QCD.",
        "positive": "Breaking the gauge symmetry in lattice gauge-invariant models: We consider the role that gauge symmetry breaking terms play on the continuum\nlimit of gauge theories in three dimensions. As a paradigmatic example we\nconsider scalar electrodynamics in which $N_f$ complex scalar fields interact\nwith a U(1) gauge field. We discuss under which conditions a gauge-symmetry\nbreaking term destabilizes the critical behavior (continuum limit) of the\ngauge-invariant theory. We find that the gauge symmetry is robust at\ntransitions at which gauge fields are not critical. At charged transitions,\nwhere gauge fields are critical, gauge symmetry is lost as soon as the\nperturbation is added."
    },
    {
        "anchor": "Lattice investigation of the phase diagram of the 1+1 dimensional\n  Gross-Neveu model at finite number of fermion flavors: We explore the phase structure of the 1+1 dimensional Gross-Neveu model at\nfinite number of fermion flavors using lattice field theory. Besides a chirally\nsymmetric phase and a homogeneously broken phase we find evidence for the\nexistence of an inhomogeneous phase, where the condensate is a spatially\noscillating function. Our numerical results include a crude $\\mu$-$T$ phase\ndiagram.",
        "positive": "Improving many flavor QCD simulations using multiple GPUs: We accelerate many-flavor lattice QCD simulations using multiple GPUs.\nMultiple pseudo-fermion fields are introduced additively and independently for\neach flavor in the many-flavor HMC algorithm. Using the independence of each\npseudo-fermion field and the blocking technique for the quark solver, we can\nassign the solver task to each GPU card. In this report we present the blocking\ntechnique for the many-flavor dynamical QCD simulations. We investigate the\neffect of the blocking and the acceleration with the multiple GPUs for the\nSchr\\\"{o}dinger functional simulations with Wilson SU(3) plaquette gauge action\nand $N_f=10$ Wilson fermions. Five pseudo-fermion fields are introduced and the\nquark solver task is distributed in the ratio of 2:3 to two GPUs. We expect a\n40% timing reduction from the single GPU case and have observed a 34% timing\nreduction in the test simulations."
    },
    {
        "anchor": "The chiral phase transition in two-flavor QCD from imaginary chemical\n  potential: We investigate the order of the finite temperature chiral symmetry\nrestoration transition for QCD with two massless fermions, by using a novel\nmethod, based on simulating imaginary values of the quark chemical potential\n$\\mu=i\\mu_i,\\mu_i\\in\\mathbb{R}$. Our method exploits the fact that, for low\nenough quark mass $m$ and large enough chemical potential $\\mu_i$, the chiral\ntransition is decidedly first order, then turning into crossover at a critical\nmass $m_c(\\mu)$. It is thus possible to determine the critical line in the $m -\n\\mu^2$ plane, which can be safely extrapolated to the chiral limit by taking\nadvantage of the known tricritical indices governing its shape. We test this\nmethod with standard staggered fermions and the result of our simulations is\nthat $m_c(\\mu=0)$ is positive, so that the phase transition at zero density is\ndefinitely first order in the chiral limit, on our coarse $N_t=4$ lattices with\n$a\\simeq 0.3\\,\\mathrm{fm}$.",
        "positive": "K -> pion Semileptonic Form Factors from Two-Flavor Lattice QCD: We present new lattice results of the K -> pion semileptonic form factors\nobtained from simulations with two flavors of dynamical twisted-mass fermions,\nusing pion masses as light as 260 MeV. Our main result is f+(0) = 0.9560 (84),\nwhich, combined with the latest experimental data for Kl3 decays, leads to\n|V_{us}| = 0.2267 (5)_exp (20)_f+(0). Using the PDG(2008) determinations of\n|Vud| and |Vub| our result implies for the unitarity relation |Vud|**2 +\n|Vus|**2 + |Vub|**2 = 1.0004 (15). For the O(p**6) term of the chiral expansion\nof f+(0) we get Df = f+(0) - 1 - f2 = -0.0214 (84)."
    },
    {
        "anchor": "Spectroscopy in the 2+1$d$ Thirring Model with $N=1$ Domain Wall\n  Fermions: We employ the domain wall fermion (DWF) formulation of the Thirring model on\na lattice in 2+1+1 dimensions and perform $N=1$ flavor Monte Carlo simulations.\nAt a critical interaction strength the model features a spontaneous\n$\\mathrm{U}(2)\\rightarrow\\mathrm{U}(1)\\otimes \\mathrm{U}(1)$ symmetry breaking;\nwe analyse the induced spin-0 mesons, both Goldstone and non-Goldstone, as well\nas the correlator of the fermion quasiparticles, in both resulting phases.\nCrucially, we determine the anomalous dimension $\\eta_\\psi\\approx 3$ at the\ncritical point, in stark contrast with the Gross-Neveu model in 3$d$ and with\nresults obtained with staggered fermions. Our numerical simulations are\ncomplemented by an analytical treatment of the free fermion correlator, which\nexhibits large early-time artifacts due to branch cuts in the propagator\nstemming from unbound interactions of the fermion with its heavy doublers.\nThese artifacts are generalisable beyond the Thirring model, being an intrinsic\nproperty of DWF, or more generally Ginsparg-Wilson fermions.",
        "positive": "Sampling the lattice Nambu-Goto string using Continuous Normalizing\n  Flows: Effective String Theory (EST) represents a powerful non-perturbative approach\nto describe confinement in Yang-Mills theory that models the confining flux\ntube as a thin vibrating string. EST calculations are usually performed using\nthe zeta-function regularization: however there are situations (for instance\nthe study of the shape of the flux tube or of the higher order corrections\nbeyond the Nambu-Goto EST) which involve observables that are too complex to be\naddressed in this way. In this paper we propose a numerical approach based on\nrecent advances in machine learning methods to circumvent this problem. Using\nas a laboratory the Nambu-Goto string, we show that by using a new class of\ndeep generative models called Continuous Normalizing Flows it is possible to\nobtain reliable numerical estimates of EST predictions."
    },
    {
        "anchor": "New approach to the Dirac spectral density in lattice gauge theory\n  applications: We report tests and results from a new approach to the spectral density and\nthe mode number distribution of the Dirac operator in lattice gauge theories.\nThe algorithm generates the spectral density of the lattice Dirac operator as a\ncontinuous function over all scales of the complete eigenvalue spectrum. This\nis distinct from an earlier method where the integrated spectral density (mode\nnumber) was calculated efficiently for some preselected fixed range of the\nintegration. The new algorithm allows global studies like the chiral condensate\nfrom the Dirac spectrum at any scale including the cutoff-dependent IR and UV\nrange of the spectrum. Physics applications include the scale-dependent mass\nanomalous dimension, spectral representation of composite fermion operators,\nand the crossover transition from the $\\epsilon$-regime of Random Matrix Theory\nto the p-regime in chiral perturbation theory. We present thorough tests of the\nalgorithm in the 2-flavor sextet SU(3) gauge theory that we continue to pursue\nfor its potential as a minimal realization of the composite Higgs scenario.",
        "positive": "Computers for Lattice QCD: The architecture and capabilities of the computers currently in use for\nlarge-scale lattice QCD calculations are described and compared. Based on this\npresent experience, possible future directions are discussed."
    },
    {
        "anchor": "Iso-vector and Iso-scalar Tensor Charges of the Nucleon from Lattice QCD: We present results for the iso-vector and flavor diagonal tensor charges\n$g^{u-d}_T$, $g^{u}_T$, $g^{d}_T$, and $g^{s}_T$ needed to probe novel tensor\ninteractions at the TeV scale in neutron and nuclear $\\beta$-decays and the\ncontribution of the quark electric dipole moment (EDM) to the neutron EDM. The\nlattice QCD calculations were done using nine ensembles of gauge configurations\ngenerated by the MILC collaboration using the HISQ action with 2+1+1 dynamical\nflavors. These ensembles span three lattice spacings $a \\approx 0.06, 0.09$ and\n$0.12 $ fm and three quark masses corresponding to the pion masses $M_\\pi\n\\approx 130, 220$ and $310 $ MeV. Using estimates from these ensembles, we\nquantify all systematic uncertainties and perform a simultaneous extrapolation\nin the lattice spacing, volume and light quark masses for the connected\ncontributions. The final estimates of the connected nucleon (proton) tensor\ncharge for the iso-vector combination is $g_T^{u-d} = 1.020(76) $ in the\n$\\bar{\\text{MS}}$ scheme at $2$ GeV. The additional disconnected quark loop\ncontributions needed for the flavor-diagonal matrix elements are calculated\nusing a stochastic estimator employing the truncated solver method with the\nall-mode-averaging technique. We find that the size of the disconnected\ncontribution is smaller than the statistical error in the connected\ncontribution. This allows us to bound the disconnected contribution and include\nit as an additional uncertainty in the flavor-diagonal charges. After a\ncontinuum extrapolation, we find $g_T^{u} = 0.774(66) $, $g_T^{d} = -0.233(28)\n$ and $g_T^{u+d} = 0.541(67) $. The strangeness tensor charge, that can make a\nsignificant contribution to the neutron EDM due to the large ratio\n$m_s/m_{u,d}$, is $g_T^{s}=0.008(9)$ in the continuum limit.",
        "positive": "Non-Universal Quantities from Dual RG Transformations: Using a simplified version of the RG transformation of Dyson's hierarchical\nmodel, we show that one can calculate all the non-universal quantities entering\ninto the scaling laws by combining an expansion about the high-temperature\nfixed point with a dual expansion about the critical point. The magnetic\nsusceptibility is expressed in terms of two dual quantities transforming\ncovariantly under the RG transformation and has a smooth limit in the\nhigh-temperature limit. Using the analogy with hamiltonian systems, the\nsimplified example discussed here is similar to the anharmonic oscillator,\nwhile more realistic examples can be tought of as coupled oscillators allowing\nresonance phenomena."
    },
    {
        "anchor": "Chiral Anomaly in Lattice QCD with Twisted Mass Wilson Fermion: The flavour singlet axial Ward identity with Osterwalder-Seiler twisted mass\nWilson fermion action is studied on a finite lattice, with finite fermion mass\nand the Wilson parameter r up to 1. Approach to the infinite volume chiral\nlimit and emergence of the anomaly is significantly better than that obtained\nwith O(a) and O(a^2) improved fermion actions. We have shown explicitly that up\nto O(g^2), parity violating terms cancel in the Ward identity even at finite\nvolume and finite lattice spacing.",
        "positive": "Partial Wave Mixing in Hamiltonian Effective Field Theory: Within general partial-wave mixing, a method for reducing the high dimension\nof the finite-volume Hamiltonian from Hamiltonian effective field theory is\nproposed. This method provides a new viewpoint on partial-wave mixing, and a\nset of matrices that can reflect the degree of partial-wave mixing. An example\nof isospin-2 $\\pi\\pi$ scattering is used to examine the consistency between\nthis method and L\\\"{u}scher's method."
    },
    {
        "anchor": "Thermal D mesons from anisotropic lattice QCD: We present results for correlators and spectral functions of open charm\nmesons using 2+1 flavours of clover fermions on anisotropic lattices. The D\nmesons are found to dissociate close to the deconfinement crossover temperature\nTc. Our preliminary results suggest a shift in the thermal D meson mass below\nTc. Mesons containing strange quarks exhibit smaller thermal modifications than\nthose containing light quarks.",
        "positive": "Histogram method in finite density QCD with phase quenched simulations: We propose a new approach to finite density QCD based on a histogram method\nwith phase quenched simulations at finite chemical potential. Integrating\nnumerically the derivatives of the logarithm of the quark determinant with\nrespect to the chemical potential, we calculate the reweighting factor and the\ncomplex phase of the quark determinant. The complex phase is handled with a\ncumulant expansion to avoid the sign problem. We examine the applicability of\nthis method."
    },
    {
        "anchor": "Lattice QCD calculation of the Collins-Soper kernel from quasi TMDPDFs: This work presents a lattice quantum chromodynamics (QCD) calculation of the\nnonperturbative Collins-Soper kernel, which describes the rapidity evolution of\nquark transverse-momentum-dependent parton distribution functions. The kernel\nis extracted at transverse momentum scales in the range 400 MeV $< q_T < 1.7$\nGeV in a calculation with dynamical fermions and quark masses corresponding to\na larger-than-physical pion mass, $m_\\pi=538(1)$ MeV. It is found that\ndifferent approaches to extract the Collins-Soper kernel from the same\nunderlying lattice QCD matrix elements yield significantly different results\nand uncertainty estimates, revealing that power corrections, such as those\nassociated with higher-twist effects, and perturbative matching between quasi\nand light-cone beam functions, cannot be neglected.",
        "positive": "A study of the 't Hooft loop in SU(2) Yang-Mills theory: We study the behaviour of the spatial and temporal 't Hooft loop at zero and\nfinite temperature in the 4D SU(2) Yang-Mills theory, using a new numerical\nmethod. In the deconfined phase $T>T_c$, the spatial 't Hooft loop exhibits a\ndual string tension, which vanishes at $T_c$ with 3D Ising-like critical\nexponent."
    },
    {
        "anchor": "Relations Between Monopoles, Instantons and Chiral Condensate: We analyze the interplay of topological objects in four dimensional QCD. The\ndistributions of color magnetic monopoles obtained in the maximum abelian gauge\nare computed around instantons in both pure and full QCD. We find an enhanced\nprobability of encountering monopoles inside the core of an instanton on gauge\nfield average. For specific gauge field configurations we visualize the\nsituation graphically. Moreover we investigate how monopole loops and\ninstantons are locally correlated with the chiral condensate.",
        "positive": "Gauge-invariant Renormalization of the Gluino-Glue operator: We study the Gluino-Glue operator in the context of Supersymmetric ${\\cal\nN}{=}1$ Yang-Mills (SYM) theory. This composite operator is gauge invariant,\nand it is directly connected to light bound states of the theory; its\nrenormalization is very important as a necessary step for the study of\nlow-lying bound states via numerical simulations. We make use of a\nGauge-Invariant Renormalization Scheme (GIRS). This requires the calculation of\nthe Green's function of a product of two Gluino-Glue operators, situated at\ndistinct space-time points. Within this scheme, the mixing with non-gauge\ninvariant operators which have the same quantum numbers is inconsequential. We\ncompute the one-loop conversion factor relating the GIRS scheme to\n$\\overline{\\rm MS}$. This conversion factor can be used in order to convert to\n$\\overline{\\rm MS}$ Green's functions which are obtained via lattice\nsimulations and are renormalized nonperturbatively in GIRS."
    },
    {
        "anchor": "The B*Bpi coupling using relativistic heavy quarks: We report on a calculation of the B*Bpi coupling in lattice QCD. The strong\nmatrix element for a B* to Bpi transition is directly related to the leading\norder low-energy constant in heavy meson chiral perturbation theory (HMChPT)\nfor B mesons. We carry out our calculation directly at the b-quark mass using a\nnon-perturbatively tuned clover action that controls discretization effects of\norder pa and (ma)^n for all n. Our analysis is performed on RBC/UKQCD gauge\nconfigurations using domain-wall fermions and the Iwasaki gauge action at two\nlattice spacings of ainverse = 1.729(25) GeV, ainverse = 2.281(28) GeV, and\nunitary pion masses down to 290 MeV. We achieve good statistical precision and\ncontrol all systematic uncertainties, giving a final result for the HMChPT\ncoupling g_b = 0.56(3)stat(7)sys in the continuum and at the physical\nlight-quark masses. This is the first calculation performed directly at the\nphysical b-quark mass and lies in the region one would expect from carrying out\nan interpolation between previous results at the charm mass and at the static\npoint.",
        "positive": "Determination of charm quark mass from temporal moments of charmonium\n  correlator with Mobius domain-wall fermion: We extract the charm quark mass and the strong coupling constant from the\ncharmonium current correlators calculated with $n_f = 2 + 1$ Mobius domain wall\nfermions. We match our lattice calculation for the temporal moments of the\ncorrelator with perturbative result known up to four-loop order, and extract\nthe charm quark mass with uncertainty less than 1%. Using the temporal moments,\nwe also confirm the correlators in the vector channel to be consistent with the\nexperimental data for the R-ratio. We used the ensembles generated by the JLQCD\ncollaboration at lattice spacings $a$ = 0.080 fm, 0.055 fm and 0.044 fm."
    },
    {
        "anchor": "The strong coupling regime of twelve flavors QCD: We summarize the results recently reported in Ref.[1] [A. Deuzeman, M.P.\nLombardo, T. Nunes da Silva and E. Pallante,\"The bulk transition of QCD with\ntwelve flavors and the role of improvement\"] for the SU(3) gauge theory with\nNf=12 fundamental flavors, and we add some numerical evidence and theoretical\ndiscussion. In particular, we study the nature of the bulk transition that\nseparates a chirally broken phase at strong coupling from a chirally restored\nphase at weak coupling. When a non-improved action is used, a rapid crossover\nis observed at small bare quark masses. Our results confirm a first order\nnature for this transition, in agreement with previous results we obtained\nusing an improved action. As shown in Ref.[1], when improvement of the action\nis used, the transition is preceded by a second rapid crossover at weaker\ncoupling and an exotic phase emerges, where chiral symmetry is not yet broken.\nThis can be explained [1] by the non hermiticity of the improved lattice\nTransfer matrix, arising from the competition of nearest-neighbor and\nnon-nearest neighbor interactions, the latter introduced by improvement and\nbecoming increasingly relevant at strong coupling and coarse lattices. We\nfurther comment on how improvement may generally affect any lattice system at\nstrong coupling, be it graphene or non abelian gauge theories inside or\nslightly below the conformal window.",
        "positive": "Nucleon-pion-state contribution in lattice calculations of moments of\n  parton distribution functions: We employ chiral perturbation theory to calculate the nucleon-pion-state\ncontribution to the 3-point correlation functions measured in lattice QCD to\ncompute various moments of parton distribution functions (quark momentum\nfraction, helicity and transversity moment). We estimate the impact of the\nnucleon-pion-state contribution on the plateau method for lattice simulations\nwith a physical pion mass. The nucleon-pion-state contribution results in an\noverestimation of all three moments. The overestimation is at the 5-20% level\nfor source-sink separations of about 1.5 fm."
    },
    {
        "anchor": "Kenneth Wilson and lattice QCD: We discuss the physics and computation of lattice QCD, a space-time lattice\nformulation of quantum chromodynamics, and Kenneth Wilson's seminal role in its\ndevelopment. We start with the fundamental issue of confinement of quarks in\nthe theory of the strong interactions, and discuss how lattice QCD provides a\nframework for understanding this phenomenon. A conceptual issue with lattice\nQCD is a conflict of space-time lattice with chiral symmetry of quarks. We\ndiscuss how this problem is resolved. Since lattice QCD is a non-linear quantum\ndynamical system with infinite degrees of freedom, quantities which are\nanalytically calculable are limited. On the other hand, it provides an ideal\ncase of massively parallel numerical computations. We review the long and\ndistinguished history of parallel-architecture supercomputers designed and\nbuilt for lattice QCD. We discuss algorithmic developments, in particular the\ndifficulties posed by the fermionic nature of quarks, and their resolution. The\ntriad of efforts toward better understanding of physics, better algorithms, and\nmore powerful supercomputers have produced major breakthroughs in our\nunderstanding of the strong interactions. We review the salient results of this\neffort in understanding the hadron spectrum, the Cabibbo-Kobayashi-Maskawa\nmatrix elements and CP violation, and quark-gluon plasma at high temperatures.\nWe conclude with a brief summary and a future perspective.",
        "positive": "Generalized parton distributions and transversity from full lattice QCD: We present here the latest results from the QCDSF collaboration for moments\nof generalized parton distributions and transversity in two-flavour QCD,\nincluding a preliminary analysis of the pion mass dependence."
    },
    {
        "anchor": "Nucleon structure in lattice QCD with dynamical domain-wall fermions\n  quarks: We report RBC and RBC/UKQCD lattice QCD numerical calculations of nucleon\nelectroweak matrix elements with dynamical domain-wall fermions (DWF) quarks.\nThe first, RBC, set of dynamical DWF ensembles employs two degenerate flavors\nof DWF quarks and the DBW2 gauge action. Three sea quark mass values of 0.04,\n0.03 and 0.02 in lattice units are used with about 200 gauge configurations\neach. The lattice cutoff is about 1.7 GeV and the spatial volume is about (1.9\nfm)^3. Despite the small volume, the ratio of the isovector vector and axial\ncharges g_A/g_V and that of structure function moments <x>_{u-d}/<x>_{Delta u -\nDelta d} are in agreement with experiment, and show only very mild quark mass\ndependence. The second, RBC/UK, set of ensembles employs one strange and two\ndegenerate (up and down) dynamical DWF quarks and Iwasaki gauge action. The\nstrange quark mass is set at 0.04, and three up/down mass values of 0.03, 0.02\nand 0.01 in lattice units are used. The lattice cutoff is about 1.6 GeV and the\nspatial volume is about (3.0 fm)^3. Even with preliminary statistics of 25-30\ngauge configurations, the ratios g_A/g_V and <x>_{u-d}/<x>_{Delta u - Delta d}\nare consistent with experiment and show only very mild quark mass dependence.\nAnother structure function moment, d_1, though yet to be renormalized, appears\nsmall in both sets.",
        "positive": "Algorithms for Lattice QCD with Dynamical Fermions: We consider recent progress in algorithms for generating gauge field\nconfigurations that include the dynamical effects of light fermions. We survey\nwhat has been achieved in recent state-of-the-art computations, and examine the\ntrade-offs between performance and control of systematic errors. We briefly\nreview the use of polynomial and rational approximations in Hybrid Monte Carlo\nalgorithms, and some of the theory of on-shell chiral fermions on the lattice.\nThis provides a theoretical framework within which we compare algorithmic\nalternatives for their implementation; and again we examine the trade-offs\nbetween speed and error control."
    },
    {
        "anchor": "A Lattice Study of the Two-photon Decay Widths for Scalar and\n  Pseudo-scalar Charmonium: In this exploratory study, two photon decay widths of pseudo-scalar\n($\\eta_c$) and scalar ($\\chi_{c0}$) charmonium are computed using two ensembles\nof $N_f=2$ twisted mass lattice QCD gauge configurations. The simulation is\nperformed two lattice ensembles with lattice spacings $a=0.067$ fm with size\n$32^3\\times{64}$ and $a=0.085$ fm with size $24^3\\times{48}$, respectively. The\nresults for the decay widths for the two charmonia are obtained which are in\nthe right ballpark however smaller than the experimental ones. Possible reasons\nfor these discrepancies are discussed.",
        "positive": "Hadronic fluctuations and correlations at nonzero chemical potential: We present a lattice study of fluctuations and correlations among the\nconserved charges baryon number and strangeness in (2+1)-flavor QCD. The\nlattice calculations are based on a Taylor expansion of the pressure. Results\nare presented at zero and nonzero density on lattices with four and six time\nslices, corresponding to a lattice spacing of $a\\approx 0.25$ fm and $a\\approx\n0.16$ fm, respectively. The quark masses are almost physical, i.e. the light\nquark mass has been chosen to one tenth of the physical strange quark mass\nwhile the strange quark mass has been set to its physical value. We find that\nall analyzed fluctuations and correlations develop a peak at nonzero density,\nwhen they are treated in an expansion up to sixth order. Especially below the\ncritical temperature ($T_c$) fluctuations and correlations increase\ndrastically, whereas above $T_c$ they are rather unaffected."
    },
    {
        "anchor": "Preconditioning the non-relativistic many-fermion problem: Preconditioning is at the core of modern many-fermion Monte Carlo algorithms,\nsuch as Hybrid Monte Carlo, where the repeated solution of a linear problem\ninvolving an ill-conditioned matrix is needed. We report on a performance\ncomparison of three preconditioning strategies, namely Chebyshev polynomials,\nstrong-coupling approximation and weak-coupling expansion. We use conjugate\ngradient (CG) on the normal equations as well as stabilized biconjugate\ngradient (BiCGStab) as solvers and focus on the fermion matrix of the unitary\nFermi gas. Our results indicate that BiCGStab is by far the most efficient\nstrategy, both in terms of the number of iterations and matrix-vector\noperations.",
        "positive": "Coupling of the light vector meson to the vector and to the tensor\n  current: We present results for the coupling of the light vector mesons to the tensor\ncurrent, relative to the standard vector meson decay constants. From an\nO(a)-improved lattice study, performed at three values of the lattice spacing\nin the quenched approximation, our final values (in the continuum limit), in\nthe MS-scheme at 2 GeV, are: (f^T/f)_rho =0.72(2)(+2/-0), (f^T/f)_K* =0.74(2),\n(f^T/f)_phi =0.76(1)."
    },
    {
        "anchor": "Renormalisation of one-link quark operators for overlap fermions with\n  L\u00fcscher-Weisz gauge action: We compute lattice renormalisation constants of one-link quark operators\n({\\it i.e.} operators with one covariant derivative) for overlap fermions and\nL\\\"uscher-Weisz gauge action in one-loop perturbation theory. Among others,\nsuch operators enter the calculation of moments of polarised and unpolarised\nhadron structure functions. Results are given for \\beta=8.45, \\beta=8.0 and\nmass parameter \\rho=1.4, which are commonly used in numerical simulations. We\napply mean field (tadpole) improvement to our results.",
        "positive": "Topological charge density around static colour sources in lattice QCD\n  with dynamical quarks: We update our numerical investigation of topological structures around static\nquarks in pure gauge QCD by results of the first runs including dynamical\nquarks. Simulations were performed on an $8^3\\times4$ lattice, with $SU(3)$\nWilson action, with 3 flavours of quarks of equal mass, both in the confinement\nand deconfinement phase. In the confinement phase we observe indications for\nthe existence of a flux tube between a static quark and antiquark, flux-tube\nbreaking for large separations, and local correlation between the topological\ncharge density and chiral condensate. In the deconfinement phase almost all\nconfigurations turn out to be topologically trivial."
    },
    {
        "anchor": "Isospin breaking corrections to meson masses and the hadronic vacuum\n  polarization: a comparative study: We calculate the strong isospin breaking and QED corrections to meson masses\nand the hadronic vacuum polarization in an exploratory study on a\n$64\\times24^3$ lattice with an inverse lattice spacing of $a^{-1}=1.78$ GeV and\nan isospin symmetric pion mass of $m_\\pi=340$ MeV. We include QED in an\nelectro-quenched setup using two different methods, a stochastic and a\nperturbative approach. We find that the electromagnetic correction to the\nleading hadronic contribution to the anomalous magnetic moment of the muon is\nsmaller than $1\\%$ for the up quark and $0.1\\%$ for the strange quark, although\nit should be noted that this is obtained using unphysical light quark masses.\nIn addition to the results themselves, we compare the precision which can be\nreached for the same computational cost using each method. Such a comparison is\nalso made for the meson electromagnetic mass-splittings.",
        "positive": "Propagator of the lattice domain wall fermion and the staggered fermion: The propagator of the domain wall fermion is calculated from the gauge\nconfigurations of the RBC-UKQCD collaborations with 2+1 dynamical flavors of\n$16^3\\times 32\\times 16$ lattice. The ambiguity of the phase is adjusted such\nthat the overlap of the solution of the conjugate gradient method and the plane\nwave at the source becomes real. The mass function becomes close to those of\nKogut-Susskind fermion, but no anomalous behavior for $u/d$-quark mass and\ns-quark mass ratio close to 0.75 appears."
    },
    {
        "anchor": "THE QCD ABACUS: A New Formulation for Lattice Gauge Theories: A quantum Hamiltonian is constructed for SU(3) lattice QCD entirely from\ncolor triplet Fermions --- the standard quarks and a new Fermionic\n``constituent'' of the gluon we call ``rishons''. The quarks are represented by\nDirac spinors on each site and the gauge fields by rishon-antirishon bilinears\non each link which together with the local gauge transforms are the generators\nof an SU(6) algebra. The effective Lagrangian for the path integral lives in\n$R^4 \\times S^1$ Euclidean space with a compact ``fifth time'' of circumference\n($\\beta$) and non-Abelian charge ($e^2$) both of which carry dimensions of\nlength. For large $\\beta$, it is conjectured that continuum QCD is reached and\nthat the dimensionless ratio $g^2 = e^2/\\beta$ becomes the QCD gauge coupling.\nThe quarks are introduced as Kaplan chiral Fermions at either end of the finite\nslab in fifth time. This talk will emphasize the gauge and algebraic structure\nof the rishon or link Fermions and the special properties that may lead to fast\ndiscrete dynamics for numerical simulations and new theoretical insight.",
        "positive": "Pomerons and Lattices: a Progress Report: We report on some attempts to use lattice QCD to investigate topics in strong\ninteractions phenomenology which are usually interpreted in terms of soft\nPomeron exchange."
    },
    {
        "anchor": "Strange and charm HVP contributions to the muon ($g - 2)$ including QED\n  corrections with twisted-mass fermions: We present a lattice calculation of the Hadronic Vacuum Polarization (HVP)\ncontribution of the strange and charm quarks to the anomalous magnetic moment\nof the muon including leading-order electromagnetic corrections. We employ the\ngauge configurations generated by the European Twisted Mass Collaboration\n(ETMC) with $N_f = 2+1+1$ dynamical quarks at three values of the lattice\nspacing ($a \\simeq 0.062, 0.082, 0.089$ fm) with pion masses in the range\n$M_\\pi \\simeq 210 - 450$ MeV. The strange and charm quark masses are tuned at\ntheir physical values. Neglecting disconnected diagrams and after the\nextrapolations to the physical pion mass and to the continuum limit we obtain:\n$a_\\mu^s(\\alpha_{em}^2) = (53.1 \\pm 2.5) \\cdot 10^{-10}$,\n$a_\\mu^s(\\alpha_{em}^3) = (-0.018 \\pm 0.011) \\cdot 10^{-10}$ and\n$a_\\mu^c(\\alpha_{em}^2) = (14.75 \\pm 0.56) \\cdot 10^{-10}$,\n$a_\\mu^c(\\alpha_{em}^3) = (-0.030 \\pm 0.013) \\cdot 10^{-10}$ for the strange\nand charm contributions, respectively.",
        "positive": "Semileptonic decays of K and D mesons in 2+1 flavor QCD: The experimentally measured rates of the semileptonic decays K -> pi l nu and\nD -> K(pi) l nu can be combined with lattice calculations of the associated\nform factors to precisely extract the CKM matrix elements |V_{us}| and\n|V_{cs(d)}|. We report on the status of form factor calculations with Fermilab\ncharm quarks and staggered light quarks on the 2+1 flavor asqtad staggered MILC\nensembles. Analysis of data for the D -> pi l nu form factor provides a\nnontrivial test of our methods via comparison with CLEO data. We discuss the\nuse of HISQ valence quarks to calculate the K -> pi l nu form factor f_+^{K\npi}(0) and describe tests of our method."
    },
    {
        "anchor": "SU(3) centre vortices underpin confinement and dynamical chiral symmetry\n  breaking: The mass function of the nonperturbative quark propagator in SU(3) gauge\ntheory shows only a weak dependence on the vortex content of the gauge\nconfigurations. Of particular note is the survival of dynamical mass generation\non vortex-free configurations having a vanishing string tension. This admits\nthe possibility that mass generation associated with dynamical chiral symmetry\nbreaking persists without confinement. In this presentation, we examine the\nlow-lying ground-state hadron spectrum of the pi, rho, N and Delta and discover\nthat while dynamical mass generation persists in the vortex-free theory, it is\nnot connected to dynamical chiral symmetry breaking. In this way, centre\nvortices in SU(3) gauge theory are intimately linked to both confinement and\ndynamical chiral symmetry breaking. We conclude that centre vortices are the\nessential underlying feature of the QCD vacuum.",
        "positive": "Non-perturbative O(a)-improvement of Wilson quark action in three-flavor\n  QCD with plaquette gauge action: We perform a non-perturbative determination of the O(a)-improvement\ncoefficient c_SW for the Wilson quark action in three-flavor QCD with the\nplaquette gauge action. Numerical simulations are carried out in a range of\n\\beta=12.0-5.2 on a single lattice size of 8^3x16 employing the Schr\\\"odinger\nfunctional setup of lattice QCD. As our main result, we obtain an interpolation\nformula for c_SW and the critical hopping parameter K_c as a function of the\nbare coupling. This enables us to remove O(a) scaling violation from physical\nobservables in future numerical simulation in the wide range of \\beta. Our\nanalysis with a perturbatively modified improvement condition for c_SW suggests\nthat finite volume effects in c_SW are not large on the 8^3x16 lattice. We\ninvestigate N_f dependence of c_SW by additional simulations for N_f=4, 2 and 0\nat \\beta=9.6. As a preparatory step for this study, we also determine c_SW in\ntwo-flavor QCD at \\beta=5.2. At this \\beta, several groups carried out\nlarge-scale calculations of the hadron spectrum, while no systematic\ndetermination of c_SW has been performed."
    },
    {
        "anchor": "New Universality Class in three dimensions: the Antiferromagnetic $RP^2$\n  model: We present the results of a Monte Carlo simulation of the $RP^2$ model in\nthree dimensions with negative coupling. We observe a second order phase\ntransition between the disordered phase and an antiferromagnetic, unfrustrated,\nordered one. We measure, with a Finite Size Scaling analysis, the thermal\nexponent, obtaining $\\nu=0.784(8)$. We have found two magnetic-type relevant\noperators whose related $\\eta$ exponents are $0.038(2)$ and $1.338(8)$\nrespectively.",
        "positive": "Three-particle systems with resonant subprocesses in a finite volume: In previous work, we have developed a relativistic, model-independent\nthree-particle quantization condition, but only under the assumption that no\npoles are present in the two-particle K matrices that appear as scattering\nsubprocesses. Here we lift this restriction, by deriving the quantization\ncondition for identical scalar particles with a G-parity symmetry, in the case\nthat the two-particle K matrix has a pole in the kinematic regime of interest.\nAs in earlier work, our result involves intermediate infinite-volume quantities\nwith no direct physical interpretation, and we show how these are related to\nthe physical three-to-three scattering amplitude by integral equations. This\nwork opens the door to study processes such as $a_2 \\to \\rho \\pi \\to \\pi \\pi\n\\pi$, in which the $\\rho$ is rigorously treated as a resonance state."
    },
    {
        "anchor": "Partially Quenched Chiral Perturbation Theory to NNLO: This paper summarizes the recent calculations of the masses and decay\nconstants of the pseudoscalar mesons at the two-loop level, or NNLO, in\nPartially Quenched Chiral Perturbation Theory (PQxPT). Possible applications\ninclude chiral extrapolations of Lattice QCD, as well as the determination of\nthe low-energy constants (LEC:s) of QCD.",
        "positive": "Towards finite density QCD with Taylor expansions: We analyze general convergence properties of the Taylor expansion of\nobservables to finite chemical potential in the framework of an effective 2+1\nflavor Polyakov-quark-meson model. To compute the required higher order\ncoefficients a novel technique based on algorithmic differentiation has been\ndeveloped. Results for thermodynamic observables as well as the phase structure\nobtained through the series expansion up to 24th order are compared to the full\nmodel solution at finite chemical potential. The available higher order\ncoefficients also allow for resummations, e.g. Pade series, which improve the\nconvergence behavior. In view of our results we discuss the prospects for\nlocating the QCD phase boundary and a possible critical endpoint with the\nTaylor expansion method."
    },
    {
        "anchor": "Random Walks with Long-Range Self-Repulsion on Proper Time: We introduce a model of self-repelling random walks where the short-range\ninteraction between two elements of the chain decreases as a power of the\ndifference in proper time. Analytic results on the exponent $\\nu$ are obtained.\nThey are in good agreement with Monte Carlo simulations in two dimensions. A\nnumerical study of the scaling functions and of the efficiency of the algorithm\nis also presented.",
        "positive": "New MC determination of the critical coupling in $\u03c6^4_2$ theory: We investigate the non-perturbative features of $\\phi^4_2$ theory in two\ndimensions, using Monte Carlo lattice methods. In particular we determine the\nratio $f_0 \\equiv g/\\mu^2$, where g is the unrenormalised coupling, in the\ninfinite volume and continuum limit. Our final result is $f_0$ = 11.055(14)."
    },
    {
        "anchor": "Testing the Witten-Veneziano Formula on the Lattice: In this proceeding contribution we report on a test of the famous\nWitten-Veneziano formula using lattice techniques. We perform dedicated\nquenched simulations and apply the spectral projector method to determine the\ntopological susceptibility in pure Yang-Mills theory. In order to compute the\nrelevant meson masses and the flavor singlet decay constant we employ lattice\nQCD with $N_f=2+1+1$ dynamical Wilson twisted mass fermions. Taking the\ncontinuum and the $SU(2)$ chiral limits we find good agreement within\nuncertainties for both sides of the formula.",
        "positive": "Exact chiral symmetry, topological charge and related topics: It has been shown recently that Dirac operators satisfying the\nGinsparg-Wilson relation provide a solution of the chirality problem in QCD at\nfinite lattice spacing. We discuss different ways to construct these operators\nand their properties. The possibility to define lattice chiral gauge theories\nis briefly discussed as well."
    },
    {
        "anchor": "Mesons Above The Deconfining Transition: We analyze temporal and spatial meson correlators in quenched lattice QCD at\nT>0. Above T_c we find different masses and (spatial) screening masses, signals\nof plasma formation, and indication of persisting mesonic excitations.",
        "positive": "tmLQCD: a program suite to simulate Wilson Twisted mass Lattice QCD: We discuss a program suite for simulating Quantum Chromodynamics on a\n4-dimensional space-time lattice. The basic Hybrid Monte Carlo algorithm is\nintroduced and a number of algorithmic improvements are explained. We then\ndiscuss the implementations of these concepts as well as our parallelisation\nstrategy in the actual simulation code. Finally, we provide a user guide to\ncompile and run the program."
    },
    {
        "anchor": "Monopoles, spectra of overlap fermions, and eta-prime meson in external\n  magnetic fields: The effects of external magnetic fields on monopoles, spectra of the overlap\nDirac operator, instantons, and the mass of the eta-prime meson are examined by\nconducting lattice QCD simulations. The uniform external magnetic fields are\napplied to gauge field configurations with $N_{f}$ = 2 + 1 flavor quarks. The\nbare quark masses are tuned in order to obtain the physical values of the pion\nmass and of the ratio $\\frac{m_{s}}{m_{u, d}}$. Standard configurations and\nconfigurations with applied external magnetic fields are generated in the color\nconfinement and deconfinement phases. The intensity of external magnetic fields\nvaries from $e|B|$ = 0.57 to 1.14 [GeV$^{2}$]. To examine the influence of\nexternal magnetic fields on monopoles, we first calculate the monopole density,\nmeasure the lengths of the monopole loops and compare them with the absolute\nvalue of the Polyakov loops. Next, using the generated configurations, we\ncompute the eigenvalues and eigenvectors of the overlap Dirac operator, which\npreserves exact chiral symmetry. To investigate how external magnetic fields\naffect the spectra of the overlap Dirac operator, we compute spectral\ndensities, compare fluctuations of the eigenvalues of the overlap Dirac\noperator with the predictions of random matrix theory, and estimate the number\nof instantons and anti-instantons from the topological charges. In addition, we\nanalyze smearing effects on these observables and chiral symmetry breaking.\nFinally, we calculate the decay constant of the pseudoscalar meson, the chiral\ncondensate, and the square mass of the eta-prime meson using the eigenvalues\nand eigenvectors. We then extrapolate the numerical results in the chiral limit\nand demonstrate the effects of external magnetic fields on the extrapolation\nresults. This article presents preliminary results.",
        "positive": "Coherent center domains from local Polyakov loops: We analyze properties of local Polyakov loops using quenched as well as\ndynamical SU(3) gauge configurations for a wide range of temperatures. It is\ndemonstrated that for both, the confined and the deconfined regime, the local\nPolyakov loop prefers phase values near the center elements 1, exp(i 2 pi/3),\nexp(-i 2 pi/3). We divide the lattice sites into three sectors according to\nthese phases and show that the sectors give rise to the formation of clusters.\nFor a suitable definition of these clusters we find that in the quenched case\ndeconfinement manifests itself as the onset of percolation of the clusters. A\npossible continuum limit of the center clusters is discussed."
    },
    {
        "anchor": "Coupling Constants for Scalar Glueball Decay: We evaluate the partial decay widths of the lightest scalar glueball to pairs\nof pseudoscalar quark-antiquark states. The calculation is done in the valence\n(quenched) approximation on a $16^3 \\time 24$ lattice at $\\beta = 5.7$. These\npredictions and values obtained earlier for the infinite volume continuum limit\nof the scalar glueball's mass are in good agreement with the observed\nproperties of $f_J(1710)$ and inconsistent with all other observed meson\nresonances.",
        "positive": "Locality and Efficient Evaluation of Lattice Composite Fields:\n  Overlap-Based Gauge Operators: We propose a novel general approach to locality of lattice composite fields,\nwhich in case of QCD involves locality in both quark and gauge degrees of\nfreedom. The method is applied to gauge operators based on the overlap Dirac\nmatrix elements, showing for the first time their local nature on realistic\npath-integral backgrounds. The framework entails a method for efficient\nevaluation of such non-ultralocal operators, whose computational cost is\nvolume-indepenent at fixed accuracy, and only grows logarithmically as this\naccuracy approaches zero. This makes computation of useful operators, such as\noverlap-based topological density, practical. The key notion underlying these\nfeatures is that of exponential insensitivity to distant fields, made rigorous\nby introducing the procedure of statistical regularization. The scales\nassociated with insensitivity property are useful characteristics of non-local\ncontinuum operators."
    },
    {
        "anchor": "Mesons at large Nc from lattice QCD: We calculate the pion and rho meson masses in quenched SU(N) gauge theories\nfor N = 2, 3, 4 and 6. Extrapolating these results to the chiral and large-N\nlimits, we find m_rho = (1.670 +/- 0.024) sqrt(sigma) = (741 +/- 11) MeV for\nthe rho meson mass at a fixed lattice spacing a \\approx 0.2093 sqrt(sigma)\n\\approx 0.093 fm where we use the (arbitrary) value (444 MeV)^2 for the string\ntension. We estimate a continuum limit large-N value, m_rho = 1.77 +/- 0.05\nsqrt(sigma). We find 1/N^2 corrections to be small and we compare our results\nto predictions from AdS/QCD.",
        "positive": "Taming lattice artifacts with Pauli--Villars fields: As fermions are added to a lattice gauge theory, one is driven to stronger\nbare coupling in order to maintain the same renormalized coupling. Stronger\nbare couplings are usually associated with larger gauge fluctuations, leading\nto larger cutoff effects and more expensive simulations. In theories with many\nlight fermions, sometimes the desired physical region cannot be reached before\nencountering a phase boundary. We show that these undesired effects can be\nreduced by adding Pauli--Villars fields. We reach significantly larger\nrenormalized couplings while at the same time damping short-distance\nfluctuations of the gauge field. This may allow for controlled continuum\nextrapolations from large lattice spacings."
    },
    {
        "anchor": "Dual representation of Polyakov loop in 3d SU(2) lattice Yang-Mills\n  theory: We consider the expectation value of a Polyakov loop in 3d SU(2) lattice\nYang--Mills theory and transform it to the dual representation in terms of sums\nover spins. The spin dependence of the amplitudes is computed explicitly by a\ngraphical method. We also determine the asymptotic (large spin) limit of the\namplitude factors.",
        "positive": "Polymer-Chain Adsorption Transition at a Cylindrical Boundary: In a recent letter, a simple method was proposed to generate solvable models\nthat predict the critical properties of statistical systems in hyperspherical\ngeometries. To that end, it was shown how to reduce a random walk in $D$\ndimensions to an anisotropic one-dimensional random walk on concentric\nhyperspheres. Here, I construct such a random walk to model the\nadsorption-desorption transition of polymer chains growing near an attractive\ncylindrical boundary such as that of a cell membrane. I find that the fraction\nof adsorbed monomers on the boundary vanishes exponentially when the adsorption\nenergy decreases towards its critical value. When the adsorption energy rises\nbeyond a certain value above the critical point whose scale is set by the\nradius of the cell, the adsorption fraction exhibits a crossover to a linear\nincrease characteristic to polymers growing near planar boundaries."
    },
    {
        "anchor": "Scale r_0 and the static potential from the CLS lattices: We report on the measurement of the static potential and the scale r_0 from\nHYP-smeared Wilson loops in two flavour QCD. We analyse the quark mass\ndependence of the potential and r_0 at three lattice spacings. We also compare\nthe QCD static potential around distance r_0 with the static potential obtained\nfrom potential models.",
        "positive": "Localised distributions and criteria for correctness in complex Langevin\n  dynamics: Complex Langevin dynamics can solve the sign problem appearing in numerical\nsimulations of theories with a complex action. In order to justify the\nprocedure, it is important to understand the properties of the real and\npositive distribution, which is effectively sampled during the stochastic\nprocess. In the context of a simple model, we study this distribution by\nsolving the Fokker-Planck equation as well as by brute force and relate the\nresults to the recently derived criteria for correctness. We demonstrate\nanalytically that it is possible that the distribution has support in a strip\nin the complexified configuration space only, in which case correct results are\nexpected."
    },
    {
        "anchor": "Nucleon structure from 2+1 flavor domain wall QCD at nearly physical\n  pion mass: The RBC and UKQCD collaborations have been investigating hadron physics in\nnumerical lattice quantum chromodynamics (QCD) with (2+1) flavors of dynamical\ndomain wall fermions (DWF) quarks that preserves continuum-like chiral and\nflavor symmetries. The strange quark mass is adjusted to physical value via\nreweighting and degenerate up and down quark masses are set as light as\npossible. In a recent study of nucleon structure we found a strong dependence\non pion mass and lattice spatial extent in isovector axialvector-current form\nfactors. This is likely the first credible evidence for the pion cloud\nsurrounding nucleon. Here we report the status of nucleon structure\ncalculations with a new (2+1)-flavor dynamical DWF ensembles with much lighter\npion mass of 180 and 250 MeV and a much larger lattice spatial exent of 4.6 fm.\nA combination of the Iwasaki and dislocation-suppressing-determinant-ratio\n(I+DSDR) gauge action and DWF fermion action allows us to generate these\nensembles at cutoff of about 1.4 GeV while keeping the residual breaking of\nchiral symmetry sufficiently small. Nucleon source Gaussian smearing has been\noptimized. Preliminary nucleon mass estimates are 0.98 and 1.05 GeV.",
        "positive": "Dirac Eigenvalue spectrum of $N_f$=2+1 QCD towards the chiral limit\n  using HISQ fermions: We utilize the eigenvalue filtering technique combined with the stochastic\nestimate of the mode number to determine the eigenvalue spectrum. Simulations\nof (2 + 1)-flavor QCD are performed using the Highly Improved Staggered Quarks\n(HISQ/tree) action on $N_{\\tau}$ = 8 lattices with aspect ratios\n$N_{\\sigma}/N_{\\tau}$ ranging from 5 to 7. The strange quark mass is fixed to\nits physical value $m_{s}^{\\rm phy}$, and the light quark masses $m_{l}$ are\nvaried from $m_{s}^{\\rm phy}/40$ to $m_{s}^{\\rm phy}/160$ which correspond to\npion mass $m_{\\pi}$ ranging from 110 MeV to 55 MeV in the continuum limit. We\ncompute the chiral condensate and $\\chi_{\\pi} - \\chi_{\\delta}$ through the\neigenvalue spectrum obtained from the the eigenvalue filtering method. We\ncompare these results with those obtained from a direct calculation of the\nobservables which involves inversions of the fermion matrix using the\nstochastic \"noise vector\" method. We find that these approaches yield\nconsistent results. Furthermore, we also investigate the quark mass and\ntemperature dependences of the Dirac eigenvalue density at zero eigenvalues to\ngain more insights about the $U_A(1)$ symmetry breaking in QCD."
    },
    {
        "anchor": "Blockspin renormalization-group study of color confinement due to\n  violation of the non-Abelian Bianchi identity: Block-spin transformation of topological defects is applied to the violation\nof the non-Abelian Bianchi identity (VMABI) on lattice defined as Abelian\nmonopoles. To get rid of lattice artifacts, we introduce various techniques\nsmoothing the vacuum. The effective action can be determined by adopting the\ninverse Monte-Carlo method. The coupling constants $F(i)$ of the effective\naction depend on the coupling of the lattice action $\\beta$ and the number of\nthe blocking step $n$. But it is found that $F(i)$ satisfy a beautiful scaling,\nthat is, they are a function of the product $b=na(\\beta)$ alone for lattice\ncoupling constants $3.0\\le\\beta\\le3.9$ and the steps of blocking $1\\le n\\le\n12$. The effective action showing the scaling behavior can be regarded as an\nalmost perfect action corresponding to the continuum limit, since $a\\to 0$ as\n$n\\to\\infty$ for fixed $b$. The almost perfect action showing the scaling is\nfound to be independent of the smooth gauges adopted here. Then we compare the\nresults with those obtained by the analytic blocking method of topological\ndefects from the continuum. The infrared monopole action can be transformed\ninto that of the string model. The physical string tension and the lowest\nglueball mass can be evaluated \\textit{analytically} by the strong-coupling\nexpansion of the string model. We get $\\sqrt{\\sigma}\\simeq\n1.3\\sqrt{\\sigma_{phys}}$ for $b\\ge 1.0\\ \\ (\\sigma_{phys}^{-1/2})$, whereas the\nscalar glueball mass is kept to be near $M(0^{++})\\sim\n3.7\\sqrt{\\sigma_{phys}}$. Also we can almost reproduce \\textit{analytically}\nthe scaling function of the squared monopole density determined numerically for\nlarge $b$ region $b>1.2\\ (\\sigma_{phys}^{-1/2})$.",
        "positive": "A multisite microcanonical updating method: We have made a study of several update algorithms using the XY model. We find\nthat sequential local overrelaxation is not ergodic at the scale of typical\nMonte Carlo simulation time. We have introduced a new multisite microcanonical\nupdate method, which yields results compatible with those of random\noverrelaxation and the microcanonical demon algorithm, which are very much\nslower, all being incompatible with the sequential overrelaxation results."
    },
    {
        "anchor": "The anomalous dimension at the infrared fixed point of Nf = 12 SU(3)\n  theory: We propose a novel renormalization scheme for the hadronic operators. As an\nexample, we show the numerical simulation result for the anomalous dimension of\nthe pseudo scalar operator of the SU(3) gauge theory coupled to Nf = 12\nfundamental fermions. The anomalous dimension of the pseudo scalar operator is\nrelated with the mass renormalization factor of the fermion thought the\npartially conserved axial-vector current (PCAC) relation. We derive the mass\nanomalous dimension at the infrared fixed point (IRFP) of the theory, and find\nthat it is given by gamma_m^*= 0.044_{-0.024}^{+0.025} (stat.)_{-0}^{+0.057}\n(syst.)_{-0.032}^{+0} (syst.), where the first systematic error comes from the\nuncertainty of the continuum extrapolation while the second one comes from the\nuncertainty of the value of the coupling constant at the IRFP.",
        "positive": "Lattice Monte Carlo Data versus Perturbation Theory: The differences between lattice Monte Carlo data and perturbation theory are\nusually associated with the ``bad'' behaviour of the bare lattice coupling g_0\ndue to the effects of large (and unknown) higher order coefficients in the g_0\nperturbative series. In this philosophy a new, renormalised coupling g' is\ndefined with the aim of reducing the higher order coefficients of the\nperturbative series in g'. An improvement in the agreement between lattice data\nand this new perturbation series is generally observed.\n  In this paper an alternative scenario is discussed where lattice artifacts\nare proposed as the cause of the disagreement between lattice data and the\ng_0-perturbative series. We find that this interpretation provides excellent\nagreement between lattice data and perturbation theory in g_0 corrected for\nlattice artifacts. We show that this viewpoint leads typically to an order of\nmagnitude improvement in the agreement between lattice data and perturbation\ntheory, compared to typical g' perturbation expansions. The success of this\nprocedure leads to a determination of Lambda_MSbar^{N_f=0} of 220 +- 20 MeV.\nLattice data studied includes quenched values of the string tension, the\nhadronic scale r_0, the discrete beta function Delta\\beta, M_rho, f_pi and the\n1P-1S splitting in charmonium. The new 3-loop term of the lattice beta-\nfunction has been incorporated in this study.\n  A discussion of the implication of this result for lattice calculations is\npresented."
    },
    {
        "anchor": "Axial-Current Matrix Elements in Light Nuclei from Lattice QCD: I present results from the first lattice QCD calculations of axial-current\nmatrix elements in light nuclei, performed by the NPLQCD collaboration.\nPrecision calculations of these matrix elements, and the subsequent extraction\nof multi-nucleon axial-current operators, are essential in refining theoretical\npredictions of the proton-proton fusion cross section, neutrino-nucleus cross\nsections and $\\beta\\beta$-decay rates of nuclei. In addition, they are expected\nto shed light on the phenomenological quenching of $g_A$ that is required in\nnuclear many-body calculations.",
        "positive": "Net baryon number fluctuations across the chiral phase transition at\n  finite density in the strong coupling lattice QCD: We investigate the net-baryon number fluctuations across the chiral phase\ntransition at finite density in the strong coupling and chiral limit. Mesonic\nfield fluctuations are taken into account by using the auxiliary field\nMonte-Carlo method. We find that the higher-order cumulant ratios, $S\\sigma$\nand $\\kappa\\sigma^2$, show oscillatory behavior around the phase boundary at\n$\\mu/T\\gtrsim 0.2$, and there exists the region where the higher-order cumulant\nratios are negative. The negative region of $\\kappa\\sigma^2$ is found to shrink\nwith increasing lattice size. This behavior agrees with the expectations from\nthe scaling analysis."
    },
    {
        "anchor": "Phase structure and critical point in heavy-quark QCD at finite\n  temperature: We study phase structure and critical point of finite-temperature QCD in the\nheavy-quark region applying the hopping parameter expansion (HPE). We first\nstudy finite-size scaling on the critical point on $N_t=4$ lattices with large\nspatial volumes taking the leading order (LO) and the next-to-leading order\n(NLO) effects of the HPE, and find that the critical scaling of the Z(2)\nuniversality class expected around the critical point of two-flavor QCD is\nrealized when the aspect ratio of the lattice is larger than about 9. This\nenables us to determine the critical point in the thermodynamic limit with high\nprecisions. By a study of the convergence of the HPE, we confirm that the\nresult of the critical point with the LO (NLO) approximation of the HPE is\nfairly accurate for $N_t=4$ (6), while we need to incorporate higher order\neffects for larger $N_t$. To extend the study to large $N_t$ lattices, we then\ndevelop a method to take the effects of higher-order terms of the HPE up to a\nsufficiently high order. We report on the status of our study on $N_t = 6$\nlattice adopting the new method.",
        "positive": "Chiral Perturbation Theory and Weak Matrix Elements: I describe recent developments in quenched chiral perturbation theory (QChPT)\nand the status of weak matrix elements involving light quarks. I illustrate\nhow, with improved statistical errors, and with calculations of the masses of\nbaryons containing non-degenerate quarks, there is now a clear need for\nextrapolations of higher order than linear in the quark mass. I describe how\nQChPT makes predictions for the functional forms to use in such extrapolations,\nand emphasize the distinction between contributions coming from chiral loops\nwhich are similar to those present in unquenched theories, and those from\n$\\eta'$ loops which are pure quenched artifacts. I describe a fit to the baryon\nmasses using the predictions of QChPT. I give a status report on the numerical\nevidence for $\\eta'$ loops, concluding that they are likely present, and are\ncharacterized by a coupling $\\delta=0.1-0.2$. I use the difference between\nchiral loops in QCD and quenched QCD to estimate the quenching errors in a\nvariety of quantities. I then turn to results for matrix elements, largely from\nquenched simulations. Results for quenched decay constants cannot yet be\nreliably extrapolated to the continuum limit. By contrast, new results for\n$B_K$ suggest a continuum, ``quenched'' value of $B_K(NDR, 2 GeV) = 0.5977 \\pm\n0.0064 \\pm 0.0166$, based on a quadratic extrapolation in $a$. The theoretical\nbasis for using a quadratic extrapolation has been confirmed. For the first\ntime there is significant evidence that unquenching changes $B_K$, and my\nestimate for the value in QCD is $B_K(NDR, 2 GeV) = 0.66 \\pm 0.02 \\pm 0.11$.\nHere the second error is a conservative estimate of the systematic error due to\nuncertainties in the effect of quenching. A less conservative viewpoint reduces\n$0.11$ to $0.03$."
    },
    {
        "anchor": "Wilson flow with naive staggered quarks: Scale setting for QCD with two flavours of staggered quarks is examined using\nWilson flow over a factor of four change in both the lattice spacing and the\npion mass. The statistics needed to keep the errors in the flow scale fixed is\nfound to increase approximately as the inverse square of the lattice spacing.\nTree level improvement of the scales t_0 and w_0 is found to be useful in most\nof the range of lattice spacings we explore. The scale uncertainty due to\nremaining lattice spacing effects is found to be about 3%. The ratio\nw_0/\\sqrt{t_0} is N_f dependent and we find its continuum limit to be 1.106 \\pm\n0.007 (stat) \\pm 0.005 (syst) for m_\\pi w_0 \\simeq 0.3.",
        "positive": "Measure of Autocorrelation Times of Local Hybrid Monte Carlo Algorithm\n  for Lattice QCD: We report on a study of the autocorrelation times of the local version of the\nHybrid Monte Carlo (LHMC) algorithm for pure gauge $SU(3)$. We compare LHMC to\nstandard multi-hit Metropolis and to the global version of the same HMC. For\nevery algorithm we measure the autocorrelation time for a variety of\nobservables and the string tension as a function of beta. The measurements\nperformed on 8^4 and 16^4 lattices indicate that the autocorrelation time of\nLHMC is significantly shorter than for the other two algorithms."
    },
    {
        "anchor": "Lattice Results for Heavy Light Matrix Elements: Lattice results for heavy light matrix elements are reviewed and some of\ntheir implications are very briefly discussed. Despite the fact that in most\ncases the lattice results for weak matrix elements at the moment have only a\nmodest accuracy of about 20--30\\% they already have important phenomenological\nrepercussions; e.g.\\ for $V_{td}/V_{ts}$, $x_s/x_d$ and $B\\to K^\\ast\\gamma$.\nPresented at the XXVII International Conference on High Energy Physics,\nGlasgow, July 1994.",
        "positive": "SO(3) Yang-Mills theory on the lattice: We numerically investigate the phase structure of pure SO(3) LGT at zero and\nnon-zero temperature in the presence of a Z2 blind monopole chemical potential.\nThe physical meaning of the different phases, a possible symmetry breaking\nmechanism as well as the existence of an order parameter for the finite\ntemperature phase transition are discussed."
    },
    {
        "anchor": "Colour flux-tubes in static Pentaquark systems: The colour fields created by the static tetraquark and pentaquark systems are\ncomputed in quenched SU(3) lattice QCD, with gauge invariant lattice operators,\nin a 24^3 x 48 lattice at beta=6.2 . We generate our quenched configurations\nwith GPUs, and detail the respective benchmanrks in different SU(N) groups.\nWhile at smaller distances the coulomb potential is expected to dominate, at\nlarger distances it is expected that fundamental flux tubes, similar to the\nflux-tube between a quark and an antiquark, emerge and confine the quarks. In\norder to minimize the potential the fundamental flux tubes should connect at\n120o angles. We compute the square of the colour fields utilizing plaquettes,\nand locate the static sources with generalized Wilson loops and with APE\nsmearing. The tetraquark system is well described by a double-Y-shaped\nflux-tube, with two Steiner points, but when quark-antiquark pairs are close\nenough the two junctions collapse and we have an X-shaped flux-tube, with one\nSteiner point. The pentaquark system is well described by a three-Y-shaped\nflux-tube where the three flux the junctions are Steiner points.",
        "positive": "Toward the excited isoscalar meson spectrum from lattice QCD: We report on the extraction of an excited spectrum of isoscalar mesons using\nlattice QCD. Calculations on several lattice volumes are performed with a range\nof light quark masses corresponding to pion masses down to about 400 MeV. The\ndistillation method enables us to evaluate the required disconnected\ncontributions with high statistical precision for a large number of meson\ninterpolating fields. We find relatively little mixing between light and\nstrange in most JPC channels; one notable exception is the pseudoscalar sector\nwhere the approximate SU(3)F octet, singlet structure of the {\\eta}, {\\eta}' is\nreproduced. We extract exotic JPC states, identified as hybrid mesons in which\nan excited gluonic field is coupled to a color-octet qqbar pair, along with\nnon-exotic hybrid mesons embedded in a qqbar-like spectrum."
    },
    {
        "anchor": "Thermodynamics of heavy-light hadrons: Ratios of cumulants of conserved net charge fluctuations are sensitive to the\ndegrees of freedom that are carriers of the corresponding quantum numbers in\ndifferent phases of strong interaction matter. We calculate second and fourth\norder cumulants of net charm and strange fluctuations and their correlations\nwith other conserved charges such as net baryon number and electric charge.\nSimulation are performed on $N_\\tau$=6 and 8 lattices using the Highly Improved\nStaggered Quark (HISQ) action with a light to strange quark mass ratio of 1/20\nand having charm quarks treated in the quenched approximation. Analysing\nappropriate ratios of these cumulants we observe that both open strange and\ncharm hadrons start to get dissociated in the chiral crossover region. We\nprovide indirect evidence for the existence of additional, experimentally yet\nunobserved open charm and strange hadrons from QCD thermodynamics. This is done\nby comparing lattice QCD results to Hadron Resonance Gas (HRG) model\ncalculations performed with a hadron spectrum as listed in the Particle Data\nTables as well as with a spectrum predicted in the relativistic quark model and\nobserved in lattice QCD calculations. We also discuss the influence of these\nexperimentally yet unobserved states on the determination of freeze-out\ntemperature and chemical potentials from heavy ion collision experiments. We\nfound that including these additional states in the HRG model leads to a\nsystematic 5-8 MeV decrease in the freeze-out temperature of strange hadrons.",
        "positive": "Large N Lattice QED: We study the $\\beta, N$ critical behaviour of non compact QED with $N$\nspecies of light fermions, using a method we have proposed for unquenched\nsimulations. We find that there exist two phase transition lines: one, second\norder, and the other, first order, that approaches asymptotically the $\\beta=0$\naxis. These two lines have different physical origin, the second one being\nentirely due to fermions effects. We discuss the effect of the approximation\nused, in terms of an expansion of the effective action in powers of $N$, and\nconclude that the general features should not be affected by this\napproximation."
    },
    {
        "anchor": "Bubble contributions to scalar correlators with mixed actions: WWithin mixed-action chiral perturbation theory (MA$\\chi$PT), Sasa's\nderivation of the bubble contribution to scalar $a_0$ meson is extended to\nthose of scalar $\\kappa$ and $\\sigma$ mesons. We revealed that $\\kappa$ bubble\nhas two double poles and $\\sigma$ bubble contains a quadratic-in-$t^2$ growth\nfactor stemming from the multiplication of two double poles for a general mass\ntuning of valence quarks and sea quarks. The corresponding preliminary\nanalytical expressions in MA$\\chi$PT with 2+1 chiral valence quarks and 2+1\nstaggered sea quarks will be helpful for lattice studies of scalar mesons.",
        "positive": "Higher moments of charge fluctuations in QCD at high temperature: We present lattice results for baryon number, strangeness and electric charge\nfluctuations as well as their correlations at finite temperature and vanishing\nchemical potentials, i.e. under conditions relevant for RHIC and LHC. We find\nthat the fluctuations change rapidly at the transition temperature $T_c$ and\napproach the ideal quark gas limit already at approximately $1.5T_c$. This\nindicates that quarks are the relevant degrees of freedom that carry the\nquantum numbers of conserved charges at $T\\geq 1.5T_c$. At low temperature,\nqualitative features of the lattice results are well described by a hadron\nresonance gas model."
    },
    {
        "anchor": "Heavy-light decay constants using clover valence quarks and three\n  flavors of dynamical improved staggered quarks: Starting in 2001, the MILC Collaboration began a large scale calculation of\nheavy-light meson decay constants using clover valence quarks on ensembles of\nthree flavor configurations. For the coarse configurations, with a=0.12 fm,\neight combinations of dynamical light and strange quarks have been analyzed.\nFor the fine configurations, with a=0.09 fm, three combinations of quark masses\nare studied. Since we last reported on this calculation, statistics have been\nincreased on the fine ensembles, and, more importantly, a preliminary value for\nthe perturbative renormalization of the axial-vector current has become\navailable. Thus, results for f_B, f_{B_s}, f_D and f_{D_s} can, in principle,\nbe calculated in MeV, in addition to decay-constant ratios that were calculated\npreviously.",
        "positive": "Delta Expansion on the Lattice and Dilated Scaling Region: A new kind of delta expansion is applied on the lattice to the d=2 non-linear\nsigma model at N=infinity and N=1 which corresponds to the Ising model. We\nintroduce the parameter delta for the dilation of the scaling region of the\nmodel with the replacement of the lattice spacing a to (1-delta)^{1/2}a. Then,\nwe demonstrate that the expansion in delta admits an approximation of the\nscaling behavior of the model at both limits of N from the information at a\nlarge lattice spacing a."
    },
    {
        "anchor": "Vacuum alignment and lattice artifacts: When a subgroup of the flavor symmetry group of a gauge theory is weakly\ncoupled to additional gauge fields, the vacuum tends to align such that the\ngauged subgroup is unbroken. At the same time, the lattice discretization\ntypically breaks the flavor symmetry explicitly, and can give rise to new\nlattice-artifact phases with spontaneously broken symmetries. We discuss the\ninterplay of these two phenomena, using chiral lagrangian techniques. Our first\nexample is two-flavor Wilson QCD coupled to electromagnetism. We also consider\nexamples of theories with staggered fermions, and demonstrate that recent\nclaims in the literature based on the use of staggered fermions are incorrect.",
        "positive": "Study of charm and beauty in QGP from unquenched lattice QCD: We present charmonium and bottomonium correlators and corresponding\nreconstructed spectral functions from full QCD calculations in the pseudoscalar\nchannel. Correlators are obtained using a mixed-action approach,\nclover-improved Wilson valence quarks on gauge field configurations generated\nwith $N_f=2+1$ HISQ sea quarks, with physical strange quark masses and light\nquark masses corresponding to $m_\\pi=315$ MeV. The charm and bottom quark\nmasses are tuned to reproduce the experimental mass spectrum of the spin\naveraged quarkonium vector mesons from the particle data group. For the\nspectral reconstruction, we use models based on perturbative spectral functions\nfrom different frequency regions like resummed thermal contributions around the\nthreshold from pNRQCD and vacuum contributions well above the threshold. We\nshow preliminary results of the reconstructed spectral function obtained for\nthe first time in our study for full QCD."
    },
    {
        "anchor": "Tricritical point in strongly coupled U(1) gauge theory with fermions\n  and scalars: We investigate the tricritical point in the lattice fermion--gauge--scalar\nmodel with U(1) gauge symmetry. In the vicinity of this point, in the phase\nwith the broken chiral symmetry, we observe the scaling behavior of the chiral\ncondensate and of the masses of composite fermion and composite scalar,\nindicating the existence of an interesting continuum limit of the model at this\npoint.",
        "positive": "Toward tensor renormalization group study of three-dimensional\n  non-Abelian gauge theory: We propose a method to represent the path integral over gauge fields as a\ntensor network. We introduce a trial action with variational parameters and\ngenerate gauge field configurations with the weight defined by the trial\naction. We construct initial tensors with indices labelling these gauge field\nconfigurations. We perform the tensor renormalization group with the initial\ntensors and optimize the variational parameters. As a first step to the TRG\nstudy of non-Abelian gauge theory in more than two dimensions, we apply this\nmethod to three-dimensional pure SU(2) gauge theory. Our result for the free\nenergy agrees with the analytical results in weak and strong coupling regimes."
    },
    {
        "anchor": "Probing the QCD Vacuum Using External Fields: The QCD vacuum can be studied using external fields. We report here results\nrespectively obtained probing the lattice QCD vacuum by means of an abelian\nmonopole field and of an abelian chromomagnetic field",
        "positive": "Finite temperature and confinement along the extra dimensions studied on\n  a five-dimensional U(1) lattice gauge model: In this paper we study the properties of the phase diagram of a simple extra\ndimensional model on the lattice at finite temperature. We consider the\nfive-dimensional pure gauge abelian model with anisotropic couplings which at\nzero temperature exhibits a new interesting phase, the layer phase. This phase\nis characterized by a massless photon living on the four dimensional subspace\nand confinement along the extra dimension. We show that, as long as the\ntemperature takes a non zero value the aforementioned layer phase disappears.\nIt would be equivalent to assume that at finite temperature the\nhigher-dimensional lattice model loses any feature of the layered structure due\nto the deconfinement which opens up the interactions between the\nthree-dimensional subspaces at finite temperature."
    },
    {
        "anchor": "Decoupling of Photon Propagator in Compact QED: In compact QED$_{2+1}$ quantum monopole fluctuations induce confinement by\nexpelling electric flux in a dual Meissner effect. Guided by Landau-Ginzburg\ntheory, one might guess that the inverse London penetration depth\n$\\lambda^{-1}$---the only physical mass scale---equals the photon propagator\nmass pole $M_\\gamma$. I show this is not true. Indeed, in the Villain\napproximation the monopole part of the partition function factorizes from the\nphoton part, whose dynamical variables are Dirac strings. Since Dirac strings\nare gauge-variant structures, I conclude that $M_\\gamma$ is physically\nirrelevant: it is not a blood relative of $\\lambda$ or any other quantity in\nthe gauge-invariant sector. This result is confirmed by numerical simulations\nin the full theory, where $M_\\gamma$ is not sensitive to monopole prohibition\nbut essentially vanishes if Dirac strings are prohibited.",
        "positive": "X(3872) and Y(4140) using diquark-antidiquark operators with lattice QCD: We discuss a recent lattice study of charmonium-like mesons with\n$J^{PC}=1^{++}$ and three quark contents $\\bar cc\\bar du$, $\\bar cc(\\bar uu +\n\\bar dd)$ and $\\bar cc\\bar ss$, where the latter two can mix with $\\bar cc$. In\nthis quantum channel, the long known exotic candidate, X(3872), resides. This\nsimulation employs $N_f=2$, $m_\\pi=266~$MeV and a large basis of $\\bar cc$,\ntwo-meson and diquark-antidiquark interpolating fields, with diquarks in both\nanti-triplet and sextet color representations. It aims at the possible\nsignatures of four-quark exotic states. Along the way, we discuss the relations\nbetween the diquark-antidiquark operators and the two-meson operators via the\nFierz transformations."
    },
    {
        "anchor": "Lattice QCD Impact on Determination of CKM Matrix: Status and Prospects: Lattice QCD is an important tool for theoretical input for flavor physics.\nThere have been four reviews by the Flavour Lattice Averaging Group (FLAG).\nThis talk will review the current status of the magnitude of eight of the nine\nCKM matrix elements, borrowing heavily from the most recent FLAG review\n(co-authored by the speaker). Future prospects for improving the determination\nof the CKM matrix will be discussed.",
        "positive": "The nature of the finite temperature QCD transition as a function of the\n  quark masses: The finite temperature QCD transition for physical quark masses is a\ncrossover. For smaller quark masses a first-order phase transition is expected.\nUsing Symanzik improved gauge and stout improved fermion action for 2+1 flavour\nstaggered QCD we give estimates/bounds for the phase line separating the\nfirst-order region from the crossover one. The calculations are carried out on\ntwo different lattice spacings. Our conclusion for the critical mass is $m_0\n\\lesssim 0.07 \\cdot m_{phys}$ for $N_T=4$ and $m_0 \\lesssim 0.12 \\cdot\nm_{phys}$ for $N_T=6$ lattices."
    },
    {
        "anchor": "Finite temperature phase transition, adjoint Polyakov loop and topology\n  in SU(2) LGT: We investigate the phase structure of pure SU(2) LGT at finite temperature in\nthe mixed fundamental and adjoint representation modified with a Z2 monopole\nchemical potential. The decoupling of the finite temperature phase transition\nfrom unphysical zero temperature bulk phase transitions is analyzed with\nspecial emphasis on the continuum limit. The possible relation of the adjoint\nPolyakov loop to an order parameter for the finite temperature phase transition\nand to the topological structure of the theory is discussed.",
        "positive": "One loop calculation of SUSY Ward-Takahashi identity on lattice with\n  Wilson fermion: One loop correction to the SUSY Ward-Takahashi identity is calculated on\nlattice with Wilson fermion. The supersymmetry on lattice is broken explicitly\nby the gluino mass and the lattice artifact. We should fine tune parameters in\nthe theory to the point given by the additive mass correction in order to\neliminate the breaking effect of lattice artifact. It is shown that the\nadditive mass correction appearing from the SUSY Ward-Takahashi identity\ncoincide with that from the axial $U(1)_R$ symmetry as was suggested by Curci\nand Veneziano. Two important symmetries of the super Yang-Mills theory can be\nrecovered simultaneously in the continuum with a single fine tuning.\n  Operator mixing of the supercurrent are also investigated. We find that the\nsupercurrent mixes only with a gauge invariant current $T_\\mu$ which is related\nto the gamma-trace anomaly."
    },
    {
        "anchor": "One-loop perturbative coupling of $A$ and $A_\\star$ through the chiral\n  overlap operator: Recently, Grabowska and Kaplan constructed a four-dimensional lattice\nformulation of chiral gauge theories on the basis of the chiral overlap\noperator. At least in the tree-level approximation, the left-handed fermion is\ncoupled only to the original gauge field~$A$, while the right-handed one is\ncoupled only to the gauge field~$A_\\star$, a deformation of~$A$ by the gradient\nflow with infinite flow time. In this paper, we study the fermion one-loop\neffective action in their formulation. We show that the continuum limit of this\neffective action contains local interaction terms between $A$ and~$A_\\star$,\neven if the anomaly cancellation condition is met. These non-vanishing terms\nwould lead an undesired perturbative spectrum in the formulation.",
        "positive": "Field sparsening for the construction of the correlation functions in\n  lattice QCD: Two field-sparsening methods, namely the sparse-grid method and the random\nfield selection method, are used in this paper for the construction of the\n2-point and 3-point correlation functions in lattice QCD. We argue that, due to\nthe high correlation among the lattice correlators at different field points\nassociated with source, current, and sink locations, one can save a lot of\ncomputational time by performing the summation over a subset of the lattice\nsites. Furthermore, with this strategy, one only needs to store a small\nfraction of the full quark propagators. It is found that the number of field\npoints can be reduced by a factor of $\\sim$100 for the point-source operator\nand a factor of $\\sim$1000 for the Gaussian-smeared operator, while the\nuncertainties of the correlators only increase by $\\sim$15\\%. Therefore, with a\nmodest cost of the computational resources, one can approach the precision of\nthe all-to-all correlators using the field-sparsening methods."
    },
    {
        "anchor": "Strange quark content of the nucleon: We discuss the calculation of disconnected diagrams needed for determining\nthe strange quark content of the nucleon on the lattice. We present results for\nthe strange scalar form factor and the related parameter f_Ts, which enters\ninto the cross-section for the scattering of dark matter off nuclei in\nsupersymmetric extensions of the standard model. In addition, we present\nresults for the strange contribution to the nucleon's axial and electromagnetic\nform factors. The calculations were performed with two dynamical flavors of\nWilson fermions on a 24^3 x 64 anisotropic lattice with a_s = 3a_t = 0.11 fm\nand M_pi ~ 400 MeV.",
        "positive": "Correlations and Binding in 4D Dynamical Triangulation: We study correlations on the euclidean spacetimes generated in Monte Carlo\nsimulations of the model. In the elongated phase, curvature correlations appear\nto fall off like a fractional power. Near the transition to the crumpled phase\nthis power is consistent with 4. We also present improved data of our\ncomputations of the binding energy of test particles."
    },
    {
        "anchor": "Static quark free energies at finite temperature with two flavors of\n  improved Wilson quarks: Polyakov loop correlations at finite temperature in two-flavor QCD are\nstudied in lattice simulations with the RG-improved gluon action and the\nclover-improved Wilson quark action. From the simulations on a $16^3 \\times 4$\nlattice, we extract the free energies, the effective running coupling $g_{\\rm\neff}(T)$ and the Debye screening mass $m_D(T)$ for various color channels of\nheavy quark--quark and quark--anti-quark pairs above the critical temperature.\nThe free energies are well approximated by the screened Coulomb form with the\nappropriate Casimir factors. The magnitude and the temperature dependence of\nthe Debye mass are compared to those of the next-to-leading order thermal\nperturbation theory and to a phenomenological formula given in terms of $g_{\\rm\neff}(T)$. Also we made a comparison between our results with the Wilson quark\nand those with the staggered quark previously reported.",
        "positive": "Thermodynamics for two flavor QCD: We conclude our analysis of the N_t=6 equation of state for two flavor QCD,\nfirst described at last year's conference. We have obtained new runs at\nam_q=0.025 and improved runs at am_q=0.0125. The results are extrapolated to\nm_q=0, and we extract the speed of sound as well. We also present evidence for\na restoration of the SU(2) X SU(2) chiral symmetry just above the crossover,\nbut not of the axial U(1) chiral symmetry."
    },
    {
        "anchor": "Lattice Field Theory with the Sign Problem and the Maximum Entropy\n  Method: Although numerical simulation in lattice field theory is one of the most\neffective tools to study non-perturbative properties of field theories, it\nfaces serious obstacles coming from the sign problem in some theories such as\nfinite density QCD and lattice field theory with the $\\theta$ term. We\nreconsider this problem from the point of view of the maximum entropy method.",
        "positive": "Resonance Scattering Phase Shifts in a 2-d Lattice Model: We study a simple 2-d model representing two fields with different mass and a\n3-point coupling term. The phase shift in the resonating 2-particle channel is\ndetermined from the energy spectrum obtained in Monte Carlo simulations on\nfinite lattices. Masses and wave function renormalization constants of the\nfields as well as mass and width of the resonance are determined and discussed.\nThe representation of scattering states in terms of the considered operators is\nanalysed."
    },
    {
        "anchor": "Simulating chiral magnetic effect and anomalous transport phenomena in\n  the pre-equilibrium stages of heavy-ion collisions: We present a first principles approach to study the Chiral Magnetic Effect\nduring the pre-equilibrium stage of a heavy-ion collision. We discuss the\ndynamics of the Chiral Magnetic Effect and Chiral Magnetic Wave based on\nreal-time lattice simulations with dynamical (Wilson and Overlap) fermions\nsimultaneously coupled to color and electromagnetic fields. While for light\nquarks we observe a dissipation-less transport of charges as in anomalous\nhydrodynamics, we demonstrate that for heavier quarks the effects of explicit\nchiral symmetry breaking lead to a significant reduction of the associated\ncurrents.",
        "positive": "Non-Abelian string breaking phenomena with Matrix Product States: Using matrix product states, we explore numerically the phenomenology of\nstring breaking in a non-Abelian lattice gauge theory, namely 1+1 dimensional\nSU(2). The technique allows us to study the static potential between external\nheavy charges, as traditionally explored by Monte Carlo simulations, but also\nto simulate the real-time dynamics of both static and dynamical fermions, as\nthe latter are fully included in the formalism. We propose a number of\nobservables that are sensitive to the presence or breaking of the flux string,\nand use them to detect and characterize the phenomenon in each of these setups."
    },
    {
        "anchor": "Properties of the renormalized quark mass in the Schrodinger functional\n  with a non-vanishing background field: We compute the current quark mass in the Schrodinger functional with a\nnon-vanishing background field at one loop order of perturbation theory. The\nresults are used to obtain the critical mass at which the renormalized quark\nmass vanishes, and some lattice artefacts at one loop order.",
        "positive": "Staggered Fermion, its Symmetry and Ichimatsu-Patterned Lattice: We investigate exact symmetries of a staggered fermion in D dimensions. The\nDirac operator is reformulated by SO(2D) Clifford algebra. The chiral symmetry,\nrotational invariance and parity symmetries are clarified in any dimension.\nLocal scalar and pseudo-scalar modes are definitely determined, in which we\nfind non-standard modes. The relation to Ichimatsu-patterned lattice approach\nis discussed."
    },
    {
        "anchor": "Electromagnetic Corrections to Meson Masses and the HVP: We present an exploratory study of the electromagnetic corrections to meson\nmasses and the hadronic vacuum polarization using $N_f=2+1$ Domain Wall\nfermions. These corrections are estimated with two different approaches, a\nstochastic approach using $U(1)$ gauge configurations for the photon fields,\nand a perturbative approach through a QED perturbative expansion of the QCD+QED\npath integral. We compare results and statistical errors from both methods.",
        "positive": "The QCD Equation of state and critical end-point estimates at $\\mathcal\n  O(\u03bc_B^6)$: We present results for the QCD Equation of State at non-zero chemical\npotentials corresponding to the conserved charges in QCD using Taylor expansion\nupto sixth order in the baryon number, electric charge and strangeness chemical\npotentials. The latter two are constrained by the strangeness neutrality and a\nfixed electric charge to baryon number ratio. In our calculations, we use the\nHighly Improved Staggered Quarks (HISQ) discretization scheme at physical quark\nmasses and at different values of the lattice spacings to control lattice\ncut-off effects. Furthermore we calculate the pressure along lines of constant\nenergy density, which serve as proxies for the freeze-out conditions and\ndiscuss their dependence on $\\mu_B$ , which is necessary for hydrodynamic\nmodelling near freezeout. We also provide an estimate of the radius of\nconvergence of the Taylor series from the 6th order coefficients which provides\na new constraint on the location of the critical end-point in the T-$\\mu_B$\nplane of the QCD phase diagram."
    },
    {
        "anchor": "Topological Susceptibility on Dynamical Staggered Fermion Configurations: The topological susceptibility is one of the few physical quantities that\ndirectly measure the properties of the QCD vacuum. Chiral perturbation theory\npredicts that in the small quark mass limit the topological susceptibility\ndepends quadratically on the pion mass, approaching zero in the chiral limit.\nLattice calculations have difficulty reproducing this behavior. In this paper\nwe study the topological susceptibility on dynamical staggered fermion\nconfigurations. Our results indicate that the lattice spacing has to be small,\naround a~0.1fm for thin link staggered fermion actions to show the expected\nchiral behavior. Our preliminary result indicates that fat link fermions, on\nthe other hand, reproduce the theoretical expectations even on lattices with\na~0.17fm. We argue that this is due to the improved flavor symmetry of fat link\nfermionic actions.",
        "positive": "Lee-Yang edge singularities in lattice QCD : A systematic study of\n  singularities in the complex $\u03bc_B$ plane using rational approximations: A new approach is presented to explore the singularity structure of lattice\nQCD at imaginary chemical potential. Our method can be seen as a combination of\nthe Taylor expansion and analytic continuation approaches. Its novelty lies in\nusing rational (Pad\\'e) approximants for studying Lee Yang edge singularities.\nThe motivation for using rational approximants will be exhibited. We will\nprovide some confidence in our approach based on numerical experiments\nperformed on well-motivated \"toy models\". Our focus lies in identifying\nsingularities of the net-baryon number density in the complex $\\mu_B$ plane. To\nthis end we have found signatures of the Roberge-Weiss critical point(and\nChiral singularities -- subject to some caveats). In this contribution we will\ndiscuss the setup, simulation parameters and results obtained for 2+1 flavor\nQCD in the complex $\\mu_B/T$ plane."
    },
    {
        "anchor": "Model study of the sign problem in a mean-field approximation: We study the sign problem of the fermion determinant at nonzero baryon\nchemical potential. For this purpose we apply a simple model derived from\nQuantum Chromodynamics, in the limit of large chemical potential and mass. For\nSU(2) color, there is no sign problem and the mean-field approximation is\nsimilar to data from the lattice. For SU(3) color the sign problem is\nunavoidable, even in a mean-field approximation. We apply a phase-reweighting\nmethod, combined with the mean-field approximation, to estimate thermodynamic\nquantities. We also investigate the mean-field free energy using a saddle-point\napproximation.",
        "positive": "High-loop perturbative renormalization constants for Lattice QCD (III):\n  three-loop quark currents for Iwasaki gauge action and n_f=4 Wilson fermions: This is the third of a series of papers on three-loop computation of\nrenormalization constants for Lattice QCD. Our main point of interest are\nresults for the regularization defined by Iwasaki gauge action and n_f=4 Wilson\nfermions. Our results for quark bilinears renormalized according to the RI'-MOM\nscheme can be compared to non-perturbative results. The latter are available\nfor Twisted Mass QCD: being defined in the chiral limit, renormalization\nconstants must be the same. We also address more general problems. In\nparticular, we discuss a few methodological issues connected to summing the\nperturbative series such as the effectiveness of Boosted Perturbation Theory\nand the disentanglement of irrelevant and finite volume contributions.\nDiscussing these issues we consider ont only the new results of this paper, but\nalso those for the regularization defined by tree-level Symanzik improved gauge\naction and n_f=2 Wilson fermions, which we presented in a recent paper of ours.\nWe finally comment to which extent the techniques we put at work in the NSPT\ncontext can provide a fresher look into the lattice version of the RI'-MOM\nscheme."
    },
    {
        "anchor": "An estimate of the eta and eta-prime meson masses in Nf=2+1 lattice QCD: Masses of the eta and eta-prime mesons are estimated in Nf=2+1 lattice QCD\nwith the non-perturbatively O(a) improved Wilson quark action and the Iwasaki\nRG-improved gluon action, using CP-PACS/JLQCD configurations on a 16^3 x 32\nlattice at beta=1.83 (lattice spacing is 0.122 fm). We apply a stochastic noise\nestimator technique combined with smearing method to evaluate correlators among\nflavor SU(2) singlet pseudoscalar operators and strange pseudoscalar operators\nfor 10 combinations of up/down and strange quark masses. The correlator matrix\nis then diagonalized to identify signals for mass eigenstates. Masses of the\nground state and the first excited state extrapolated to the physical point are\nm_eta= 0.545(16) GeV and m_eta-prime= 0.871(46) GeV, being close to the\nexperimental values of the eta and eta-prime masses.",
        "positive": "Topological susceptibility from the twisted mass Dirac operator spectrum: We present results of our computation of the topological susceptibility with\n$N_f=2$ and $N_f=2+1+1$ flavours of maximally twisted mass fermions, using the\nmethod of spectral projectors. We perform a detailed study of the quark mass\ndependence and discretization effects. We make an attempt to confront our data\nwith chiral perturbation theory and extract the chiral condensate from the\nquark mass dependence of the topological susceptibility. We compare the value\nwith the results of our direct computation from the slope of the mode number.\nWe emphasize the role of autocorrelations and the necessity of long Monte Carlo\nruns to obtain results with good precision. We also show our results for the\nspectral projector computation of the ratio of renormalization constants\n$Z_P/Z_S$."
    },
    {
        "anchor": "Unquenched simulations with N_f=2 light quark flavours: The quark mass dependence of meson masses and decay constants in N_f=2 QCD is\nstudied at a fixed gauge coupling with different dynamical quark masses.\nPartially Quenched Wilson Chiral Perturbation Theory (PQWchiPT) is applied to\nobtain the extrapolation to zero quark mass. It is shown, that in our analysis\nNNLO-terms play a more important role than O(a)-terms, which can be neglected.\nAlso we compare our results with recent CP-PACS results.",
        "positive": "Lattice simulation of SU(2) gauge theory with chirally symmetric\n  fermions: We numerically study the SU(2) gauge theory with two dynamical flavors of the\ndomain-wall fermions in fundamental representation. The meson spectra and the\nresidual mass are measured on three lattice volumes and at two values of gauge\ncoupling so as to investigate the finite volume effect. On generated\nconfigurations, eigenvalues of the overlap fermion operator are determined and\ncompared to the random matrix theory. To quantify the effect of violation of\nthe exact chiral symmetry, we measure the correlation between the eigenvectors\nof the domain-wall and the overlap operators."
    },
    {
        "anchor": "Polyakov loop effects on the phase diagram in strong-coupling lattice\n  QCD: We investigate the Polyakov loop effects on the QCD phase diagram by using\nthe strong-coupling (1/g^2) expansion of the lattice QCD (SC-LQCD) with one\nspecies of unrooted staggered quark, including O}(1/g^4) effects. We take\naccount of the effects of Polyakov loop fluctuations in Weiss mean-field\napproximation (MFA), and compare the results with those in the Haar-measure MFA\n(no fluctuation from the mean-field). The Polyakov loops strongly suppress the\nchiral transition temperature in the second-order/crossover region at small\nchemical potential, while they give a minor modification of the first-order\nphase boundary at larger chemical potential. The Polyakov loops also account\nfor a drastic increase of the interaction measure near the chiral phase\ntransition. The chiral and Polyakov loop susceptibilities have their peaks\nclose to each other in the second-order/crossover region. In particular in\nWeiss MFA, there is no indication of the separated deconfinement transition\nboundary from the chiral phase boundary at any chemical potential. We discuss\nthe interplay between the chiral and deconfinement dynamics via the bare quark\nmass dependence of susceptibilities.",
        "positive": "Percolation and Deconfinement in SU(2) Gauge Theory: Cluster percolation and second order thermal phase transitions show an\namazing number of common features: power laws of the variables at criticality,\nscaling relations of the critical exponents and universality of the critical\nindices. Because of that, percolation theory seems to be an ideal framework to\ndevise a geometrical picture of a second order phase transition; the leading\ncharacters of the phenomenon are ordered domains, whose size increases while\napproaching the threshold until they fuse into a spanning structure, so that\nthe order from local becomes global. Such a geometrical picture is known to be\nsuccessful in the Ising model. The clusters are site-bond clusters, i.e. they\nare built by joining nearest-neighbouring aligned spins with some\ntemperature-dependent bond probability. In this work we extend this result to a\nwide variety of theories, from continuous Ising-like models to O(n) models. On\nthe grounds of these results, we devise a percolation picture for the confining\nphase transition of SU(2) pure gauge theory, exploiting its analogies with the\nIsing model. The cluster definition is obtained by constructing suitable\neffective theories for SU(2), which admit an equivalent percolation\nformulation."
    },
    {
        "anchor": "Spectral density analysis of time correlation functions in lattice QCD\n  using the maximum entropy method: We study various aspects of extracting spectral information from time\ncorrelation functions of lattice QCD by means of Bayesian inference with an\nentropic prior, the maximum entropy method (MEM). Correlator functions of a\nheavy-light meson-meson system serve as a repository for lattice data with\ndiverse statistical quality. Attention is given to spectral mass density\nfunctions, inferred from the data, and their dependence on the parameters of\nthe MEM. We propose to employ simulated annealing, or cooling, to solve the\nBayesian inference problem, and discuss practical issues of the approach.",
        "positive": "Normalizing flows for the real-time sign problem: We discuss the application of normalizing flows to bosonic lattice field\ntheories with real-time sign problems. A normalizing flow, once it is found for\nsuch a lattice field theory, is guaranteed to solve its sign problem. We argue\nfor the existence of normalizing flows for bosonic lattice field theories in\nthe Schwinger-Keldish formalism in a few ways. We then discuss how this\nexistence is a specific feature of bosonic theories: such arguments break down\nfor fermionic systems, whether at finite density or in real-time."
    },
    {
        "anchor": "Shaken, but not stirred - Potts model coupled to quantum gravity: We investigate the critical behaviour of both matter and geometry of the\nthree-state Potts model coupled to two-dimensional Lorentzian quantum gravity\nin the framework of causal dynamical triangulations. Contrary to what general\narguments of the effects of disorder suggest, we find strong numerical evidence\nthat the critical exponents of the matter are not changed under the influence\nof quantum fluctuations in the geometry, compared to their values on fixed,\nregular lattices. This lends further support to previous findings that quantum\ngravity models based on causal dynamical triangulations are in many ways better\nbehaved than their Euclidean counterparts.",
        "positive": "Landau-Ginzburg-Wilson approach to critical phenomena in the presence of\n  gauge symmetries: We critically reconsider the Landau-Ginzburg-Wilson (LGW) approach to\ncritical phenomena in the presence of gauge symmetries. In the LGW framework,\nto obtain the universal features of a continuous transition, one identifies the\norder parameter Phi and considers the corresponding most general Phi4 field\ntheory that has the same symmetries as the original model. In the presence of\ngauge symmetries, one usually considers a gauge-invariant order parameter and a\nLGW field theory that is invariant under the global symmetries of the original\nmodel. We show that this approach, in which the gauge dynamics is effectively\nintegrated out, may sometimes lead to erroneous conclusions on the nature of\nthe critical behavior. As an explicit example, we show that the above-described\nLGW approach generally fails for the three-dimensional ferromagnetic and\nantiferromagnetic CP(N-1) models, which are invariant under global U(N) and\nlocal U(1) transformations. We point out possible implications for the\nfinite-temperature chiral transition of nuclear matter."
    },
    {
        "anchor": "The continuum limit of the lattice Gribov problem, and a solution based\n  on Hodge decomposition: We study gauge fixing via the standard local extremization algorithm for\n2-dimensional $U(1)$. On a lattice with spherical topology $S^2$ where all\ncopies are lattice artifacts, we find that the number of these 'Gribov' copies\ndiverges in the continuum limit. On a torus, we show that lattice artifacts can\nlead to the wrong evaluation of the gauge-invariant correlation length, when\nmeasured via a gauge-fixed procedure; this bias does not disappear in the\ncontinuum limit. We then present a new global approach, based on Hodge\ndecomposition of the gauge field, which produces a unique smooth field in\nLandau gauge, and is economically powered by the FFT. We also discuss the use\nof this method for examining topological objects, and its extensions to\nnon-abelian gauge fields.",
        "positive": "Exotic mesons in quenched lattice QCD: Since gluons in QCD are interacting fundamental constituents just as quarks\nare, we expect that in addition to mesons made from a quark and an antiquark,\nthere should also be glueballs and hybrids (bound states of quarks, antiquarks\nand gluons). In general, these states would mix strongly with the conventional\nq-bar-q mesons. However, they can also have exotic quantum numbers inaccessible\nto q-bar-q mesons. Confirmation of such states would give information on the\nrole of \"dynamical\" color in low energy QCD. In the quenched approximation we\npresent a lattice calculation of the masses of mesons with exotic quantum\nnumbers. These hybrid mesons can mix with four quark (q-bar-q-bar-q-q) states.\nThe quenched approximation partially suppresses this mixing. Nonetheless, our\nhybrid interpolating fields also couple to four quark states. Using a four\nquark source operator, we demonstrate this mixing for the 1-+ meson. Using the\nconventional Wilson quark action, we calculate both at reasonably light quark\nmasses, intending to extrapolate to small quark mass, and near the charmed\nquark mass, where we calculate the masses of some c-bar-c-g hybrid mesons. The\nhybrid meson masses are large --- over 4 GeV for charmonium and more than twice\nthe vector meson mass at our smallest quark mass, which is near the strange\nquark mass."
    },
    {
        "anchor": "QCD Spectrum --- 1996: Progress on the calculation of the spectrum from lattice calculations is\nreviewed. Particular emphasis is placed on discussing our ability to control\npossible systematic errors coming from finite volume, and extrapolations in\nquark mass and lattice spacing. Recent approaches based on improved actions are\ncompared.",
        "positive": "Individual eigenvalue distributions for chGSE-chGUE crossover and\n  determination of low-energy constants in two-color QCD+QED: We compute statistical distributions of individual low-lying eigenvalues of\nrandom matrix ensembles interpolating chiral Gaussian symplectic and unitary\nensembles. To this aim we use the Nystrom-type discretization of Fredholm\nPfaffians and resolvents of the dynamical Bessel kernel containing a single\ncrossover parameter \\rho. The \\rho-dependent distributions of the four smallest\neigenvalues are then used to fit the Dirac spectra of modulated SU(2) lattice\ngauge theory, in which the reality of the staggered SU(2) Dirac operator is\nweakly violated either by the U(1) gauge field or by a constant background\nflux. Combined use of individual eigenvalue distributions is effective in\nreducing statistical errors in \\rho; its linear dependence on the imaginary\nchemical potential \\mu_I enables precise determination of the pseudo-scalar\ndecay constant F of the SU(2) gauge theory from a small lattice. The\nU(1)-coupling dependence of an equivalent of F^2 \\mu_I^2 in the SU(2) x U(1)\ntheory is also obtained."
    },
    {
        "anchor": "Finite-size scaling and the deconfinement transition in gauge theories: We introduce a new method for determining the critical indices of the\ndeconfinement transition in gauge theories. The method is based on the finite\nsize scaling behavior of the expectation value of simple lattice operators,\nsuch as the plaquette. We test the method for the case of SU(3) pure gauge\ntheory in (2+1) dimensions and obtain a precise determination of the critical\nindex $\\nu$, in agreement with the prediction of the Svetitsky-Yaffe\nconjecture.",
        "positive": "The PHMC algorithm for simulations of dynamical fermions: I --\n  description and properties: We give a detailed description of the so-called Polynomial Hybrid Monte Carlo\n(PHMC) algorithm. The effects of the correction factor, which is introduced to\nrender the algorithm exact, are discussed, stressing their relevance for the\nstatistical fluctuations and (almost) zero mode contributions to physical\nobservables. We also investigate rounding-error effects and propose several\nways to reduce memory requirements."
    },
    {
        "anchor": "Is the Up Quark Massless?: Several lattice calculations of a combination of the low energy constants of\nthe chiral Lagrangian, 2\\alpha_8-\\alpha_5, are presented. This combination is\ncritical for the preclusion of a massless up quark. The result found is\n2\\alpha_8-\\alpha_5 = 0.115 \\pm 0.051^{stat} \\pm 0.25^{syst}, which is well\noutside of the range allowed by a massless up quark.",
        "positive": "Two-color QCD at high density: QCD at high chemical potential has interesting properties such as\ndeconfinement of quarks. Two-color QCD, which enables numerical simulations on\nthe lattice, constitutes a laboratory to study QCD at high chemical potential.\nAmong the interesting properties of two-color QCD at high density is the\ndiquark condensation, for which we present recent results obtained on a finer\nlattice compared to previous studies. The quark propagator in two-color QCD at\nnon-zero chemical potential is referred to as the Gor'kov propagator. We\nexpress the Gor'kov propagator in terms of form factors and present recent\nlattice simulation results."
    },
    {
        "anchor": "Progress in $x$-dependent partonic distributions from lattice QCD: We review the latest progress in lattice QCD calculations of the partonic\nstructure of hadrons. This structure is, in particular, described in terms of\n$x$-dependent distributions, the simplest of which are the standard parton\ndistribution functions (PDFs). The lattice calculations rely on matrix elements\nprobing spatial correlations between partons in a boosted hadron, that can be\nmatched to light-cone correlations defining the relevant distributions. We\ndiscuss the recent theoretical and practical refinements of this strategy, as\nwell as new exploratory directions. The latter include generalized parton\ndistributions (GPDs), distributions beyond leading twist, flavor-singlet\ndistributions and transverse-momentum dependent PDFs (TMDs). We also shortly\nconsider the potential future impact of lattice data on phenomenology.",
        "positive": "News on Disconnected Diagrams: We present evidence for disconnected contributions to the $\\sigma_{\\pi N}$\nterm and the flavor singlet axial coupling $g_A^0$ of the proton on full QCD\nconfigurations, which are obtained by means of improved stochastic estimator\ntechniques. Furthermore we discuss results from the fermionic determination of\nthe topological charge of the QCD vacuum (in the spirit of the Athiya-Singer\ntheorem) again achieved with stochastic estimator methods. It turns out that\nthis approach provides an monitor for the tunneling efficiency of the HMC on\nQCD with dynamical Wilson fermions which is independent on the pure gluonic\nmethod that implies cooling."
    },
    {
        "anchor": "Dyson instability for 2D nonlinear O(N) sigma models: For lattice models with compact field integration (nonlinear sigma models\nover compact manifolds and gauge theories with compact groups) and satisfying\nsome discrete symmetry, the change of sign of the bare coupling g_0^2 at zero\nresults in a mere discontinuity in the average energy rather than the\ncatastrophic instability occurring in theories with integration over\narbitrarily large fields. This indicates that the large order of perturbative\nseries and the non-perturbative contributions should have unexpected features.\nUsing the large-N limit of 2-dimensional nonlinear O(N) sigma model, we discuss\nthe complex singularities of the average energy for complex 't Hooft coupling\nlambda= g_0^2N. A striking difference with the usual situation is the absence\nof cut along the negative real axis. We show that the zeros of the partition\nfunction can only be inside a clover shape region of the complex lambda plane.\nWe calculate the density of states and use the result to verify numerically the\nstatement about the zeros. We propose dispersive representations of the\nderivatives of the average energy for an approximate expression of the\ndiscontinuity. The discontinuity is purely non-perturbative and contributions\nat small negative coupling in one dispersive representation are essential to\nguarantee that the derivatives become exponentially small when lambda -> 0^+ We\ndiscuss the implications for gauge theories.",
        "positive": "Multi-hadron operators with all-to-all quark propagators: Hadron spectroscopy on dynamical configurations are faced with the\ndifficulties of dealing with the mixing of single particle states and\nmulti-hadron states (for large spatial volumes and light dynamical quarks\nmasses). It is conceivable that explicit multi-hadron interpolating operators\nwill be necessary for obtaining sufficiently good overlap onto multi-hadron\nstates in order to extract the low-lying excitation spectrum. We explore here\nthe feasibility of using four noise diluted all-to-all quark propagators in the\nconstruction of explicit two-hadron operators on quenched, anisotropic\nlattices. Our longer term goal is to use these operators on large anisotropic,\ndynamical configurations for hadron spectroscopy."
    },
    {
        "anchor": "Overview of lattice calculations of the $x$-dependence of PDFs, GPDs and\n  TMDs: For a long time, lattice QCD was unable to address the $x$-dependence of\npartonic distributions, direct access to which is impossible in Euclidean\nspacetime. Recent years have brought a breakthrough for such calculations when\nit was realized that partonic light-cone correlations can be accessed through\nspatial correlations computable on the lattice. Appropriately devised\nobservables can be factorized into physical PDFs via a perturbative procedure\ncalled matching, analogous to the standard factorization of experimental cross\nsections. In this short review, aimed at a broader high-energy and nuclear\nphysics community, we discuss the recent highlights of this research program.\nKey concepts are outlined, followed by a case study illustrating the typical\nstage of current lattice extractions and by a brief review of the most recent\nexplorations. We finalize with a number of messages for the prospects of\nlattice determinations of partonic structure.",
        "positive": "Nucleon structure from stochastic estimators: Using stochastic estimators for connected meson and baryon three-point\nfunctions has successfully been tried in the past years. Compared to the\nstandard sequential source method we trade the freedom to compute the\ncurrent-to-sink propagator independently of the hadron sink for additional\nstochastic noise in our observables. In the case of the nucleon we can use this\nfreedom to compute many different sink-momentum/polarization combinations,\nwhich grants access to more virtualities. We will present preliminary results\non the scalar, electro-magnetic and axial form factors of the nucleon in\n$N_f=2+1$ lattice QCD and contrast the performance of the stochastic method to\nthe sequential source method. We find the stochastic method to be competitive\nin terms of errors at fixed cost."
    },
    {
        "anchor": "A Proposal of a Renormalization Group Transformation for Lattice Field\n  Theories: We propose a new Real Space Renormalization Group transformation useful for\nMonte Carlo calculations in theories with global or local symmetries. From\nrelaxation arguments we define the block-spin transformation with two tunable\nfree parameters, adapted to the system's action. Varying them it is possible to\nplace the fixed point very close to the simulation point. We show how the\nmethod works in a simple model with global symmetry: the three dimensional XY\nmodel.",
        "positive": "Lattice QCD for Cosmology: We present a full result for the equation of state (EoS) in 2+1+1 (up/down,\nstrange and charm quarks are present) flavour lattice QCD. We extend this\nanalysis and give the equation of state in 2+1+1+1 flavour QCD. In order to\ndescribe the evolution of the universe from temperatures several hundreds of\nGeV to several tens of MeV we also include the known effects of the electroweak\ntheory and give the effective degree of freedoms. As another application of\nlattice QCD we calculate the topological susceptibility (chi) up to the few GeV\ntemperature region. These two results, EoS and chi, can be used to predict the\ndark matter axion's mass in the post-inflation scenario and/or give the\nrelationship between the axion's mass and the universal axionic angle, which\nacts as a initial condition of our universe."
    },
    {
        "anchor": "New One-Flavor Hybrid Monte Carlo Simulation Method for Lattice Fermions\n  with gamma-five Hermiticity: We propose a new method for Hybrid Monte Carlo (HMC) simulations with odd\nnumbers of dynamical fermions on the lattice. It employs a different approach\nfrom polynomial or rational HMC. In this method, gamma-five hermiticity of the\nlattice Dirac operators is crucial and it can be applied to Wilson,\ndomain-wall, and overlap fermions. We compare HMC simulations with two\ndegenerate flavors and (1 + 1) degenerate flavors using optimal domain-wall\nfermions. The ratio of the efficiency, (number of accepted trajectories) /\n(simulation time), is about 3:2. The relation between pseudofermion action of\nchirally symmetric lattice fermions in four-dimensional(overlap) and\nfive-dimensional(domain-wall) representation are also analyzed.",
        "positive": "Neutral Kaon mixing beyond the Standard Model: We compute the hadronic matrix elements of the four-quark operators needed\nfor the study of $K^0-{\\bar K^0}$ mixing beyond the Standard Model. We have\nused $n_f=2+1$ flavours of domain wall fermion (DWF) at two values of the\nlattice spacing ($a\\approx0.08$ and $a\\approx0.11\\text{fm}$) and with lightest\nunitary pion mass of $\\approx300\\,\\text{MeV}$. Renormalisation is performed\nnon-perturbatively and the impact of different intermediate momentum schemes is\ninvestigated."
    },
    {
        "anchor": "Topological vacuum structure of the Schwinger model with matrix product\n  states: We numerically study the single-flavor Schwinger model with a topological\n$\\theta$-term, which is practically inaccessible by standard lattice Monte\nCarlo simulations due to the sign problem. By using numerical methods based on\ntensor networks, especially the one-dimensional matrix product states, we\nexplore the non-trivial $\\theta$-dependence of several lattice and continuum\nquantities in the Hamiltonian formulation. In particular, we compute the\nground-state energy, the electric field, the chiral fermion condensate, and the\ntopological vacuum susceptibility for positive, zero, and even negative fermion\nmass. In the chiral limit, we demonstrate that the continuum model becomes\nindependent of the vacuum angle $\\theta$, thus respecting CP invariance, while\nlattice artifacts still depend on $\\theta$. We also confirm that negative\nmasses can be mapped to positive masses by shifting $\\theta\\rightarrow \\theta\n+\\pi$ due to the axial anomaly in the continuum, while lattice artifacts\nnon-trivially distort this mapping. This mass regime is particularly\ninteresting for the (3+1)-dimensional QCD analog of the Schwinger model, the\nsign problem of which requires the development and testing of new numerical\ntechniques beyond the conventional Monte Carlo approach.",
        "positive": "Decay constants $f_B$ and $f_{B_s}$ and quark masses $m_b$ and $m_c$\n  from HISQ simulations: We present a progress report on our calculation of the decay constants $f_B$\nand $f_{B_s}$ from lattice-QCD simulations with highly-improved staggered\nquarks. Simulations are carried out with several heavy valence-quark masses on\n$(2+1+1)$-flavor ensembles that include charm sea quarks. We include data at\nsix lattice spacings and several light sea-quark masses, including an\napproximately physical-mass ensemble at all but the smallest lattice spacing,\n0.03 fm. This range of parameters provides excellent control of the continuum\nextrapolation to zero lattice spacing and of heavy-quark discretization errors.\nFinally, using the heavy-quark effective theory expansion we present a method\nof extracting from the same correlation functions the charm- and bottom-quark\nmasses as well as some low-energy constants appearing in the heavy-quark\nexpansion."
    },
    {
        "anchor": "Lattice results on gluon and ghost propagators in Landau gauge: We present clear evidence of strong effects of Gribov copies in Landau gauge\ngluon and ghost propagators computed on the lattice at small momenta by\nemploying a new approach to Landau gauge fixing and a more effective numerical\nalgorithm. It is further shown that the new approach substantially decreases\nnotorious finite-volume effects.",
        "positive": "CP and T violation in non-perturbative chiral gauge theories: We give a completely general derivation revealing the precise origin and the\nquantitative effects of CP and T violations in chiral gauge theories on the\nlattice."
    },
    {
        "anchor": "Mass spectra of mesons containing charm quarks - continuum limit results\n  from twisted mass fermions: We present results from an ongoing computation of masses of $D$ mesons, $D_s$\nmesons and charmonium, including both ground states and several parity and\nangular momentum excitations. We employ 2+1+1 flavours of dynamical maximally\ntwisted mass fermions at three lattice spacings and three $u/d$ quark masses at\neach lattice spacing. We consider different combinations of valence quark\ndiscretizations, with either identical or opposite signs in front of the\ntwisted mass terms. In the end, our setup allows for a good control of\ndifferent kinds of systematic effects, in particular the quark mass dependence\nof the resulting meson masses and cut-off effects. We obtain good agreement\nwith experiment for the majority of states and we discuss improvements that\nwill be made to finalize the analysis.",
        "positive": "Fortran MPI Checkerboard Code for SU(3) Lattice Gauge Theory II: We study the performance of MPI checkerboard code for SU(3) lattice gauge\ntheory as function of the number of MPI processes, which run in parallel on an\nidentical number of CPU cores. Computing platforms explored are a small PC\ncluster at FSU and the Cray at NERSC."
    },
    {
        "anchor": "Quantum Behaviour of the Flux Tube: A comparison between QFT predictions\n  and lattice gauge theory simulations: We review some universal features of the colour flux tube of gauge theories\nin the confining phase predicted by the infrared conformal limit of the\nunderlying string theory. In particular we discuss shape effects in Wilson\nloops and rederive in a general way the logarithmic growth of the mean square\nwidth of the flux tube as a function of the interquark separation. Recent data\non three-dimensional Z_2 gauge theory, combined with high precision data on the\ninterface physics of the 3D Ising model fit nicely to this behaviour over a\nrange of more than two orders of magnitude",
        "positive": "Physical observables from boundary artifacts: scalar glueball in\n  Yang-Mills theory: By relating the functional averages of a generic scalar operator in\nsimulations with Open (O) and Periodic (P) boundary conditions (BCs)\nrespectively for $SU(3)$ lattice gauge theory, we show that the scalar glueball\nmass and the glueball to vacuum matrix element can be extracted very\nefficiently from the former. Numerical results are compared with those\nextracted from the two point function of the time slice energy density (both\nPBC and OBC). The scaling properties of the mass and the matrix element are\nstudied with the help of Wilson (gradient) flow."
    },
    {
        "anchor": "Themodynamics for pure SU($2$) gauge theory using gradient flow: We study the equation of state of pure SU($2$) gauge theory using Monte Carlo\nsimulations. The scale-setting of lattice parameters has been carried by using\nthe gradient flow. We propose a reference scale $t_0$ for the SU($2$) gauge\ntheory satisfying $t^2 \\langle E \\rangle|_{t=t_0} =0.1$, which is fixed by a\nnatural scaling-down of the standard $t_0$-scale for the SU($3$) case based on\nperturbative analyses. We also show the thermodynamic quantities as a function\nof $T/T_c$, which are derived by the energy-momentum tensor using the small\nflow-time expansion of the gradient flow.",
        "positive": "Overlap valence quarks on a twisted mass sea: a case study for mixed\n  action Lattice QCD: We discuss a Lattice QCD mixed action investigation employing Wilson\nmaximally twisted mass sea and overlap valence fermions. Using four values of\nthe lattice spacing, we demonstrate that the overlap Dirac operator assumes a\npoint-like locality in the continuum limit. We also show that by adopting\nsuitable matching conditions for the sea and valence theories a consistent\ncontinuum limit for the pion decay constant and light baryon masses can be\nobtained. Finally, we confront results for sea-valence mixed meson masses and\nthe valence scalar correlator with corresponding expressions of chiral\nperturbation theory. This allows us to extract low energy constants of mixed\naction chiral perturbation which characterize the strength of unitarity\nviolations in our mixed action setup."
    },
    {
        "anchor": "Complex Langevin simulation of QCD at finite density and low temperature\n  using the deformation technique: We study QCD at finite density and low temperature by using the complex\nLangevin method. We employ the gauge cooling to control the unitarity norm and\nintroduce a deformation parameter in the Dirac operator to avoid the\nsingular-drift problem. The reliability of the obtained results are judged by\nthe probability distribution of the magnitude of the drift term. By making\nextrapolations with respect to the deformation parameter using only the\nreliable results, we obtain results for the original system. We perform\nsimulations on a $4^3\\times 3$ lattice and show that our method works well even\nin the region where the reweighting method fails due to the severe sign\nproblem. As a result we observe a delayed onset of the baryon number density as\ncompared with the phase-quenched model, which is a clear sign of the Silver\nBlaze phenomenon.",
        "positive": "Detecting monopoles on the lattice: We address the issue why the number and the location of magnetic monopoles\ndetected on lattice configurations are gauge dependent, in contrast with the\nphysical expectation that monopoles have a gauge invariant status. By use of\nthe Non-Abelian Bianchi Identities we show that monopoles are gauge invariant,\nbut the efficiency of the technique usually adopted to detect them depends on\nthe choice of the gauge in a well understood way. In particular we have studied\na class of gauges which interpolates between the Maximal Abelian gauge, where\nall monopoles are observed, and the Landau gauge, where all monopoles escape\ndetection."
    },
    {
        "anchor": "A Study of Gluon Propagator on Coarse Lattice: We study gluon propagator in Landau gauge with lattice QCD, where we use an\nimproved lattice action. The calculation of gluon propagator is performed on\nlattices with the lattice spacing from 0.40 fm to 0.24 fm and with the lattice\nvolume from $(2.40 fm)^4$ to $(4.0 fm)^4$. We try to fit our results by two\ndifferent ways, in the first one we interpret the calculated gluon propagators\nas a function of the continuum momentum, while in the second we interpret the\npropagators as a function of the lattice momentum. In the both we use models\nwhich are the same in continuum limit. A qualitative agreement between two\nfittings is found.",
        "positive": "$B \\rightarrow \u03c0\\ell \u03bd$ with M\u00f6bius Domain Wall Fermions: We report on the status of our calculation of the exclusive semileptonic\ndecay, $B\\rightarrow \\pi \\ell \\nu$; a key process in the determination of the\nCKM matrix element $|V_{ub}|$. The M\\\"{o}bius domain wall action is used for\nboth light and heavy quarks on gauge ensembles that include the effects of\n$2+1$ flavours of quarks in the sea at three values of the lattice spacing:\n$a\\approx 0.08~\\mathrm{fm}$, $a\\approx0.055~\\mathrm{fm}$, and\n$a\\approx0.044~\\mathrm{fm}$. Pion masses go down to $300~\\mathrm{MeV}$ while\nheavy quarks masses are as large as $2.44m_c$. We present preliminary results\nof form factors from this process, showing dependence on momentum transfer,\nlattice spacing, and the heavy quark mass."
    },
    {
        "anchor": "SESAM and TXL Results for Wilson Action--A Status Report: Results from two studies of full QCD with two flavours of dynamical Wilson\nfermions are presented. At beta=5.6, the region 0.83 > m_pi/m_rho > 0.56 at\nm_pia > 0.23 L^{-1} is explored. The SESAM collaboration has generated\nensembles of about 200 statistically independent configurations on a 16^3 x\n32-lattice at three different kappa-values and is entering the final phase of\ndata analysis. The TXL simulation on a 24^3 x 40-lattice at two kappa-values\nhas reached half statistics and data analysis has started recently, hence most\nresults presented here are preliminary. The focus of this report is fourfold:\nwe demonstrate that algorithmic improvements like fast Krylov solvers and\nparallel preconditioning recently introduced can be put into practise in full\nQCD simulations, we present encouraging observations as to the critical\ndynamics of the Hybrid Monte Carlo algorithm in the approach to the chiral\nlimit, we mention signal improvements of noisy estimator techniques for\ndisconnected diagrams to the pi-N sigma term, and we report on SESAM's results\nfor light hadron spectrum, light quark masses, and heavy quarkonia.",
        "positive": "The index theorem in QCD with a finite cut-off: The fixed point Dirac operator on the lattice has exact chiral zero modes on\ntopologically non-trivial gauge field configurations independently whether\nthese configurations are smooth, or coarse. The relation $n_L-n_R = Q^{FP}$,\nwhere $n_L$ $(n_R)$ is the number of left (right)-handed zero modes and\n$Q^{FP}$ is the fixed point topological charge holds not only in the continuum\nlimit, but also at finite cut-off values. The fixed point action, which is\ndetermined by classical equations, is local, has no doublers and complies with\nthe no-go theorems by being chirally non-symmetric. The index theorem is\nreproduced exactly, nevertheless. In addition, the fixed point Dirac operator\nhas no small real eigenvalues except those at zero, i.e. there are no\n'exceptional configurations'."
    },
    {
        "anchor": "Quark mass renormalization with non-exceptional momenta: Renormalization conditions imposed on quark bilinear vertex functions in the\nconventional RI/MOM scheme use exceptional momentum configurations. With\npractical values for the lattice cutoff, these vertex functions are\ncontaminated with unwanted low energy physics (pion pole, zero modes, etc),\nwhich is a large source of systematic error. These effects can be reduced by\nusing non-exceptional momenta. We discuss the quark mass renormalization with\nnon-exceptional momenta using 2+1 flavor domain wall fermions based on a\nrecently proposed RI/SMOM scheme.",
        "positive": "Quarkonium spin structure in lattice NRQCD: Numerical simulations of the quarkonium spin splittings are done in the\nframework of lattice nonrelativistic quantum chromodynamics (NRQCD). At leading\norder in the velocity expansion the spin splittings are of $O(M_Q v^4)$, where\n$M_Q$ is the renormalized quark mass and $v^2$ is the mean squared quark\nvelocity. A systematic analysis is done of all next-to-leading order\ncorrections. This includes the addition of $O(M_Q v^6)$ relativistic\ninteractions, and the removal of $O(a^2 M_Q v^4)$ discretization errors in the\nleading-order interactions. Simulations are done for both S- and P-wave mesons,\nwith a variety of heavy quark actions and over a wide range of lattice\nspacings. Two prescriptions for the tadpole improvement of the action are also\nstudied in detail: one using the measured value of the average plaquette, the\nother using the mean link measured in Landau gauge. Next-to-leading order\ninteractions result in a very large reduction in the charmonium splittings,\ndown by about 60% from their values at leading order. There are further\nindications that the velocity expansion may be poorly convergent for\ncharmonium. Prelimary results show a small correction to the hyperfine\nsplitting in the Upsilon system."
    },
    {
        "anchor": "The density of states method in Yang-Mills theories and first order\n  phase transitions: Extensions of the standard model that lead to first-order phase transitions\nin the early universe can produce a stochastic background of gravitational\nwaves, which may be accessible to future detectors. Thermodynamic observables\nat the transition, such as the latent heat, can be determined by lattice\nsimulations, and then used to predict the expected signatures in a given\ntheory. In lattice calculations, the emergence of metastabilities in proximity\nof the phase transition may make the precise determination of these observables\nquite challenging, and may lead to large uncontrolled numerical errors. In this\ncontribution, we discuss as a prototype lattice calculation the first order\ndeconfinement transition that arises in the strong SU(3) Yang-Mills sector. We\nadopt the novel logarithmic linear relaxation method, which can provide a\ndetermination of the density of states of the system with exponential error\nsuppression. Thermodynamic observables can be reconstructed with a controlled\nerror, providing a promising direction for accurate model predictions in the\nfuture.",
        "positive": "A novel nonperturbative renormalization scheme for local operators: The gradient flow exponentially suppresses ultraviolet field fluctuations and\nremoves ultraviolet divergences (up to a multiplicative fermionic wavefunction\nrenormalization). It can be used to describe real-space Wilsonian\nrenormalization group transformations and determine the corresponding beta\nfunction. We propose a new nonperturbative renormalization scheme for local\ncomposite fermionic operators that uses the gradient flow and is amenable to\nlattice QCD calculations. We present preliminary nonperturbative results for\nthe running of quark bilinear operators in this scheme and outline the\ncalculation of perturbative matching to the MS-bar scheme."
    },
    {
        "anchor": "A Ginsparg-Wilson Approach to Lattice Chern-Simons Theory: The concept of lattice modified symmetry formulations is adapted to the\nparity symmetry of gauge fields and applied to the pure Abelian Chern-Simons\naction in three dimensions. We derive an analogue of the Ginsparg-Wilson\nrelation for the parity anti-symmetry, which is motivated from the perfect\nlattice action, and which we denote as the Chern-Simons-Ginsparg-Wilson\nrelation (CSGWR). In addition to the overlap type solutions, we construct\nexplicitly simple and local polynomial solutions to the CSGWR. We show that\nthese actions are exactly invariant under a lattice modified parity\ntransformation. That transformation is local as well, and it turns into the\nstandard parity transformation in the continuum limit.",
        "positive": "Phenomenology from the Lattice: In recent years the precision of lattice calculations has improved hugely,\nand the results are making a very significant impact in particle physics\nphenomenology. Indeed there is no alternative general method which can be used\nin the evaluation of nonperturbative strong interaction effects for a wide\nvariety of physical processes. In this talk I discuss a selection of topics in\nflavour physics, including \\textit{mature} quantities for which lattice\ncalculations have been performed for a long time (e.g. the determination of the\n$V_{us}$ CKM matrix element and $B_K$), quantities which we are now learning to\nstudy (e.g. $K\\to\\pi\\pi$ decays amplitudes and the spectrum and mixing of\n$\\eta-\\eta^\\prime$ mesons) and important phenomenological quantities for which\na large amount of experimental data is available but which we do not yet\nunderstand how to approach in lattice simulations (e.g. nonleptonic B-decays).\nThe improvement in precision and the extension of the range of processes which\ncan be studied using lattice QCD has to be continued vigorously if precision\nflavour physics is to play a complementary role to large $p_\\perp$ discovery\nexperiments at the LHC in unravelling the next level of fundamental physics."
    },
    {
        "anchor": "Meson screening masses from lattice QCD with two light and the strange\n  quark: We present results for screening masses of mesons built from light and\nstrange quarks in the temperature range of approximately between 140 MeV to 800\nMeV. The lattice computations were performed with 2+1 dynamical light and\nstrange flavors of improved (p4) staggered fermions along a line of constant\nphysics defined by a pion mass of about 220 MeV and a kaon mass of 500 MeV. The\nlattices had temporal extents Nt = 4, 6 and 8 and aspect ratios of Ns / Nt \\geq\n4. At least up to a temperature of 140 MeV the pseudo-scalar screening mass\nremains almost equal to the corresponding zero temperature pseudo-scalar (pole)\nmass. At temperatures around 3Tc (Tc being the transition temperature) the\ncontinuum extrapolated pseudo-scalar screening mass approaches very close to\nthe free continuum result of 2 \\pi T from below. On the other hand, at high\ntemperatures the vector screening mass turns out to be larger than the free\ncontinuum value of 2 \\pi T. The pseudo-scalar and the vector screening masses\ndo not become degenerate even for a temperature as high as 4Tc. Using these\nmesonic spatial correlation functions we have also investigated the restoration\nof chiral symmetry and the effective restoration of the axial symmetry. We have\nfound that the vector and the axial-vector screening correlators become\ndegenerate, indicating chiral symmetry restoration, at a temperature which is\nconsistent with the QCD transition temperature obtained in previous studies. On\nthe other hand, the pseudo-scalar and the scalar screening correlators become\ndegenerate only at temperatures larger than 1.3Tc, indicating that the\neffective restoration of the axial symmetry takes place at a temperature larger\nthan the QCD transition temperature.",
        "positive": "Charm as a domain wall fermion in quenched lattice QCD: We report a study describing the charm quark by a domain-wall fermion (DWF)\nin lattice quantum chromodynamics (QCD). Our study uses a quenched gauge\nensemble with the DBW2 rectangle-improved gauge action at a lattice cutoff of\n$a^{-1} \\sim 3$ GeV. We calculate masses of heavy-light (charmed) and\nheavy-heavy (charmonium) mesons with spin-parity $J^P = 0^\\mp$ and $1^\\mp$,\nleptonic decay constants of the charmed pseudoscalar mesons ($D$ and $D_s$),\nand the $D^0$-$\\bar{D^0}$ mixing parameter. The charm quark mass is found to be\n$m^{\\bar{\\rm MS}}_{c}(m_{c})=1.24(1)(18)$ GeV. The mass splittings in\ncharmed-meson parity partners $\\Delta_{q,J=0}$ and $\\Delta_{q, J=1}$ are\ndegenerate within statistical errors, in accord with experiment, and they\nsatisfy a relation $\\Delta_{q=ud, J} > \\Delta_{q=s, J}$, also consistent with\nexperiment. A C-odd axial vector charmonium state, $h_c), lies 22(11) MeV above\nthe $\\chi_{c1}$ meson, or $m_{h_{c}} = 3533(11)_{\\rm stat.}$ MeV using the\nexperimental $\\chi_{c1}) mass. However, in this regard, we emphasize\nsignificant discrepancies in the calculation of hyperfine splittings on the\nlattice. The leptonic decay constants of $D$ and $D_s$ mesons are found to be\n$f_D=232(7)_{\\rm stat.}(^{+6}_{-0})_{\\rm chiral}(11)_{\\rm syst.}$ MeV and\n$f_{D_s}/f_{D} = 1.05(2)_{\\rm stat.}(^{+0}_{-2})_{\\rm chiral}(2)_{\\rm syst.}$,\nwhere the first error is statistical, the second a systematic due to chiral\nextrapolation and the third error combination of other known systematics. The\n$D^0$-$\\bar{D^0}$ mixing bag parameter, which enters the $\\Delta C = 2$\ntransition amplitude, is found to be $B_D(2{GeV})=0.845(24)_{\\rm\nstat.}(^{+24}_{-6})_{\\rm chiral}(105)_{\\rm syst.}$."
    },
    {
        "anchor": "Searching for continuous phase transitions in 5D SU(2) lattice gauge\n  theory: We study the phase diagram of 5-dimensional $SU(2)$ Yang-Mills theory on the\nlattice. We consider two extensions of the fundamental plaquette Wilson action\nin the search for the continuous phase transition suggested by the $4+\\epsilon$\nexpansion. The extensions correspond to new terms in the action: i) a unit size\nplaquette in the adjoint representation or ii) a two-unit sided square\nplaquette in the fundamental representation. We use Monte Carlo to sample the\nfirst and second derivative of the entropy near the confinement phase\ntransition, with lattices up to $12^{5}$. While we exclude the presence of a\nsecond order phase transition in the parameter space we sampled for model i),\nour data is not conclusive in some regions of the parameter space of model ii).",
        "positive": "2018 Update on $\\varepsilon_K$ with lattice QCD inputs: We present updated results for $\\varepsilon_K$ determined directly from the\nstandard model (SM) with lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $F_K$, and $m_c$. We find that\nthe standard model with exclusive $|V_{cb}|$ and other lattice QCD inputs\ndescribes only 70% of the experimental value of $|\\varepsilon_K|$ and does not\nexplain its remaining 30%, which leads to a strong tension in $|\\varepsilon_K|$\nat the $4\\sigma$ level between the SM theory and experiment. We also find that\nthis tension disappears when we use the inclusive value of $|V_{cb}|$ obtained\nusing the heavy quark expansion based on QCD sum rules."
    },
    {
        "anchor": "Renormalization of strongly coupled U(1) lattice gauge theories: Recent numerical studies of the 4D pure compact U(1) lattice gauge theory, I\nhave participated in, are reviewed. We look for a possibility to construct an\ninteresting nonperturbatively renormalizable continuum theory at the phase\ntransition between the confinement and Coulomb phases. First I describe the\nnumerical evidence, obtained from calculation of bulk observables on spherical\nlattices, that the theory has a non-Gaussian fixed point. Further the\ngauge-ball spectrum in the confinement phase is presented and its universality\nconfirmed. The unexpected result is that, in addition to massive states, the\ntheory contains a very light, possibly massless scalar gauge ball. I also\nsummarize results of studies of the compact U(1) lattice theory with fermion\nand scalar matter fields and point out that at strong coupling it represents a\nmodel of dynamical fermion mass generation.",
        "positive": "Topological clusters in SU(2) gluodynamics at finite temperature and the\n  evidence for KvB calorons: We report on our search for Kraan-van Baal calorons in finite temperature\nSU(2) lattice ensembles. We also discuss recent progress made in developing a\ncaloron-anticaloron gas model decribing confinement and deconfinement in the\ncontext of trivial and non-trivial holonomy."
    },
    {
        "anchor": "Symmetry and Z_2-Orbifolding Approach in Five-dimensional Lattice Gauge\n  Theory: In a lattice gauge-Higgs unification scenario using a Z_2-orbifolded\nextra-dimension, we find a new global symmetry in a case of SU(2) bulk gauge\nsymmetry. It is a global symmetry on sites in a fixed point with respect to\nZ_2-orbifolding, independent of the bulk gauge symmetry. It is shown that the\nvacuum expectation value of a Z_2-projected Polyakov loop is a good order\nparameter of the new symmetry. The effective theory on lattice is also\ndiscussed.",
        "positive": "Renormalization of bilinear quark operators for the chirally improved\n  lattice Dirac operator: We compute non-perturbative renormalization constants of fermionic bilinears\nfor the chirally improved lattice fermions in the quenched approximation of\nQCD. We address finite size effects and the influence of Gribov copies. Our\nresults are presented in the RI' and MSbar schemes as well as in RGI form and\nwe discuss relations between the renormalization constants implied by chiral\nsymmetry. After publication we corrected the numerator of the first coefficient\nof \\alpha_s^3 in (24) from 3696847 to 3890527, which yields a 0.2% higher value\nof the conversion coefficient at \\mu=2 GeV."
    },
    {
        "anchor": "QCD at nonzero temperature and density: The properties of hot hadronic matter are of great importance to the studies\nof heavy-ion collisions, cosmology and compact star formation. I briefly\noutline the current methods in use in the lattice simulations of QCD\nthermodynamics at zero and nonzero density. I discuss the most recent results\nfor the QCD phase transition, critical behavior and the equation of state.",
        "positive": "Fluctuations of conserved charges in strong magnetic fields from lattice\n  QCD: We present the first lattice QCD results of the second order fluctuations of\nand correlations among net baryon number, electric charge and strangeness in\n(2+1)-flavor lattice QCD in the presence of a background magnetic field with\nphysical pion mass $m_{\\pi}=135$ MeV. To mimic the magnetic field strength\nproduced in the early stage of heavy-ion collision experiments we use 6\ndifferent values of the magnetic field strength up to $ \\sim $10$m_{\\pi}^2$. We\nfind that the correlations between baryon number and electric charge along the\ntransition line are substantially affected by magnetic fields in the current\n$eB$ window, which could be useful for probing the existence of a magnetic\nfield in heavy-ion collision experiments."
    },
    {
        "anchor": "Deconfinement and Quarkonium Suppression: Modifications in the production pattern of heavy quark bound states have long\nbeen considered to provide sensitive signatures for the thermal properties of\ndense matter created in heavy ion collisions. The original concept of Matsui\nand Satz for quarkonium suppression as signature for deconfinement in heavy ion\ncollisions has been challenged recently through lattice studies of spectral\nfunctions, which indicate the persistence of heavy quark bound states at\ntemperatures well above the transition, as well as through the refined analysis\nof hadronization and recombination models, which take into account the thermal\nevolution of the medium generated in a heavy ion collision. We will review here\nrecent developments on these topics.",
        "positive": "The sigma meson from lattice QCD with two-pion interpolating operators: In this article we describe our studies of the sigma meson, f_0(500), using\ntwo-pion correlation functions. We use lattice quantum chromodynamics in the\nquenched approximation with so-called clover fermions. By working at unphysical\npion masses we are able to identify a would-be resonance with mass less than $2\nm_\\pi$, and then extrapolate to the physical point. We include the most\nimportant annihilation diagram, which is \"partially disconnnected\" or \"single\nannihilation.\" Because this diagram is quite expensive to compute, we introduce\na somewhat novel technique for the computation of all-to-all diagrams, based on\nmomentum sources and a truncation in momentum space. In practice, we use only\n${\\bf p}=0$ modes, so the method reduces to wall sources. At the point where\nthe mass of the pion takes its physical value, we find a resonance in the\n$0^{++}$ two-pion channel with a mass of approximately $609 \\pm 80$ MeV,\nconsistent with the expected properties of the sigma meson, given the\napproximations we are making."
    },
    {
        "anchor": "Finite volume effects for nucleon and heavy meson masses: We apply the resummed version of the L\\\"uscher formula to analyze finite\nvolume corrections to the mass of the nucleon and of heavy mesons. We show that\nby applying the subthreshold expansion of the scattering amplitudes one can\nexpress the finite volume corrections in terms of only a few physical\nobservables and the size of the box. In the case of the nucleon, the available\ninformation about the quark mass dependence of these physical quantities is\ndiscussed and used to assess the finite volume corrections to the nucleon mass\nas a function of the quark mass including a detailed analysis of the remaining\nuncertainties. For heavy mesons, the L\\\"uscher formula is derived both fully\nrelativistically and in a nonrelativistic approximation and a first attempt at\na numerical analysis is made.",
        "positive": "Conserving Lattice Gauge Theory for Finite Systems: In this contribution I discuss a recent proposal of a novel action for\nlattice gauge theory for finite systems, which accommodates non-periodic\nspatial boundary conditions. Drawing on the summation-by-parts formulation of\nfinite differences and finite volume strategies of computational\nelectrodynamics, an action is constructed that implements the proper integral\nform of Gauss' law and exhibits an inherently symmetric energy momentum tensor,\nall while realizing automatic ${\\cal O}(a)$ improvement. Its central\ningredients are illustrated using Abelian gauge theory as example."
    },
    {
        "anchor": "Radiative decays of charmonia on the lattice: We present the results of our lattice QCD study of the hadronic matrix\nelements relevant to the physical radiative J/psi -> eta_c gamma and hc ->\neta_c gamma decays. From computations with Nf=2 dynamical quark in twisted mass\nQCD at four lattice spacings, we were able to take the continuum limit and\nobtained Gamma(J/psi -> eta_c gamma) = 2.64(11) keV and Gamma(hc -> eta_c\ngamma) = 0.72(5) MeV. We also computed the the hyperfine splitting and found\nthat it does not depend from the sea quark mass and we obtain Delta = m_J/psi -\nm_eta_c = 112(4) MeV.",
        "positive": "Lattice study of vacuum polarization function and determination of\n  strong coupling constant: We calculate the vacuum polarization functions on the lattice using the\noverlap fermion formulation.By matching the lattice data at large momentum\nscales with the perturbative expansion supplemented by Operator Product\nExpansion (OPE), we extract the strong coupling constant $\\alpha_s(\\mu)$ in\ntwo-flavor QCD as $\\Lambda^{(2)}_{\\overline{MS}}$ = $0.234(9)(^{+16}_{- 0})$\nGeV, where the errors are statistical and systematic, respectively. In\naddition, from the analysis of the difference between the vector and\naxial-vector channels, we obtain some of the four-quark condensates."
    },
    {
        "anchor": "Thermodynamics and heavy-quark free energies at finite temperature and\n  density with two flavors of improved Wilson quarks: Thermodynamics of two-flavor QCD at finite temperature and density is studied\non a $16^3 \\times 4$ lattice, using a renormalization group improved gauge\naction and the clover improved Wilson quark action. In the simulations along\nlines of constant $m_{\\rm PS}/m_{\\rm V}$, we calculate the Taylor expansion\ncoefficients of the heavy-quark free energy with respect to the quark chemical\npotential ($\\mu_q$) up to the second order. By comparing the expansion\ncoefficients of the free energies between quark($Q$)and antiquark($\\bar{Q}$),\nand between $Q$ and $Q$, we find a characteristic difference at finite $\\mu_q$\ndue to the first order coefficient of the Taylor expansion. We also calculate\nthe quark number and isospin susceptibilities, and find that the second order\ncoefficient of the quark number susceptibility shows enhancement around the\npseudo-critical temperature.",
        "positive": "Dynamical Fermions with Fat Links: We present and test a new method for simulating dynamical fermions with fat\nlinks. Our construction is based on the introduction of auxiliary but dynamical\ngauge fields and works with any fermionic action and can be combined with any\nfermionic updating. In our simulation we use an over-relaxation step which\nmakes it effective. For four flavors of staggered fermions first results\nindicate that flavor symmetry at a lattice spacing a~0.2 fm is restored to a\nfew percent. With the standard action this amount of flavor symmetry\nrestoration is achieved at a~0.07 fm. We estimate that the overall\ncomputational cost is reduced by at least a factor 10."
    },
    {
        "anchor": "Density of states and Fisher's zeros in compact U(1) pure gauge theory: We present high-accuracy calculations of the density of states using\nmulticanonical methods for lattice gauge theory with a compact gauge group U(1)\non 4^4, 6^4 and 8^4 lattices. We show that the results are consistent with weak\nand strong coupling expansions. We present methods based on Chebyshev\ninterpolations and Cauchy theorem to find the (Fisher's) zeros of the partition\nfunction in the complex beta=1/g^2 plane. The results are consistent with\nreweighting methods whenever the latter are accurate. We discuss the volume\ndependence of the imaginary part of the Fisher's zeros, the width and depth of\nthe plaquette distribution at the value of beta where the two peaks have equal\nheight. We discuss strategies to discriminate between first and second order\ntransitions and explore them with data at larger volume but lower statistics.\nHigher statistics and even larger lattices are necessary to draw strong\nconclusions regarding the order of the transition.",
        "positive": "Monopoles and hadron spectrum in quenched QCD: We study quenched hadron spectra with Wilson fermion in abelian gauge fields\nextracted by maximal abelian projection and in fields induced by monopoles on\n$16^3 \\times 32 $ and $ 12^3 \\times 24$ lattices. Pion mass squared and quark\nmass defined through the axial Ward identity satisfy the PCAC relation. Gross\nfeatures of the light hadron spectra are almost similar to those in SU(3) gauge\nfields if normalization is made by the square root of the string tension. It is\nalso shown that no sizable dynamical mass generation is found in the present\nrange of $\\kappa$ when the monopole degree of freedom is removed from the\nabelian fields or from the SU(3) gauge fields."
    },
    {
        "anchor": "Self-organized criticality: I review the concept of self-organized criticality, wherein dissipative\nsystems naturally drive themselves to a critical state with important phenomena\noccurring over a wide range of length and time scales. Several exact results\nare demonstrated for the Abelian sandpile.",
        "positive": "The Nambu-Jona-Lasinio model with staggered fermions: We investigate the neighbourhood of the chiral phase transition in a lattice\nNambu--Jona-Lasinio model, using both Monte Carlo methods and lattice\nSchwinger-Dyson equations."
    },
    {
        "anchor": "On the $D^*_s$ and charmonia leptonic decays: Among the different scenarios of New Physics, those with an extended Higgs\nsector are examined with a lot of attention. Recent experimental observations\nof several anomalies in flavour physics with respect to expectations of the\nStandard Model further motivate the effort of phenomenologists. First,\ninformations about the $R_{D_s}$ ratio, a test of lepton flavour universality\nequivalent to $R_D$, already measured, but with the $s$ quark as spectator, are\nawaited in coming years to constrain the corner of an extended Higgs sector\nwith charged doublets. On another side, leptonic widths of pseudoscalar\nquarkonia are particularly interesting to test an extended Higgs sector with a\nlight CP-odd Higgs boson singlet, through the study of its mixing with\nquarkonia states. Hadronic parameters entering those processes have to be\ndetermined from lattice QCD with enough confidence on the control of systematic\nerrors. We report on the very first step of a long-term program tackled with\n${\\rm N_f}=2$ Wilson-Clover fermions to put relevant constraints on extensions\nof the Higgs sector: extraction of decay constants of $D^*_s$, $\\eta_c$,\n$\\eta_c(2S)$, $J/\\psi$ and $\\psi(2S)$ with lattice ensembles provided by the\nCLS effort, considering 2 lattice spacings and a large range of pion masses to\nestimate cut-off effects and extrapolate results to the chiral limit.",
        "positive": "Unexpected Results in the Chiral Limit with Staggered Fermions: A cluster algorithm is constructed and applied to study the chiral limit of\nthe strongly coupled lattice Schwinger model involving staggered fermions. The\nalgorithm is based on a novel loop representation of the model. Finite size\nscaling of the chiral susceptibility based on data from lattices of size up to\n$64\\times 64$ indicates the absence of long range correlations at strong\ncouplings. Assuming that there is no phase transition at a weaker coupling, the\nresults imply that all mesons acquire a mass at non-zero lattice spacings.\nAlthough this does not violate any known physics, it is surprising since\ntypically one expects a single pion to remain massless at non-zero lattice\nspacings in the staggered fermion formulation."
    },
    {
        "anchor": "Nonperturbative running of the quark mass for $N_f=3$ QCD from the\n  chirally rotated Schr\u00f6dinger Functional: We study the Renormalisation Group (RG) running of the quark mass, for\n$N_f=3$ QCD with Wilson fermions in a mixed action setup, with standard\nSchr\\\"odinger Functional (SF) boundary conditions for sea quarks and chirally\nrotated Schr\\\"odinger Functional ($\\chi$SF) boundary conditions for valence\nquarks. This necessitates the tuning of the boundary factor $z_f(g_0^2)$ of the\n$\\chi$SF valence action, in order to ensure that QCD symmetries are fully\nrecovered in the continuum. The properties of this novel setup are monitored\nthrough the ratios $Z_S/Z_P$ and $\\Sigma_S/\\Sigma_P$ of the renormalisation\nparameters and step scaling functions of the scalar and pseudoscalar densities.\nWhere comparison is possible, our $Z_S/Z_P$ results are found to agree with\nprevious determinations, based on a mass ratio method arXiv:1906.03445 and Ward\nidentities arXiv:2005.01352, arXiv:2101.10969, with Schr\\\"odinger Functional\nboundary conditions. The behaviour of $\\Sigma_S/\\Sigma_P$ confirms the\ntheoretical expectations of $\\chi$SF QCD, related to the restoration of the\ntheory's symmetries in the continuum limit. From the step scaling function of\nthe pseudoscalar density we obtain the quark mass RG-running function from\nhadronic to perturbative energy scales. This is fully compatible with the\nearlier result obtained in a similar setup for Wilson quarks with Schr\\\"odinger\nFunctional boundary conditions arXiv:1802.05243 and provides a strong\nuniversality test for the two lattice setups.",
        "positive": "Numerical results from large N reduced QCD_2: Some results in QCD_2 at large N are presented using the reduced model on the\nlattice. Overlap fermions are used to compute meson propagators."
    },
    {
        "anchor": "Equivariant Transformer is all you need: Machine learning, deep learning, has been accelerating computational physics,\nwhich has been used to simulate systems on a lattice. Equivariance is essential\nto simulate a physical system because it imposes a strong induction bias for\nthe probability distribution described by a machine learning model. This\nreduces the risk of erroneous extrapolation that deviates from data symmetries\nand physical laws. However, imposing symmetry on the model sometimes occur a\npoor acceptance rate in self-learning Monte-Carlo (SLMC). On the other hand,\nAttention used in Transformers like GPT realizes a large model capacity. We\nintroduce symmetry equivariant attention to SLMC. To evaluate our architecture,\nwe apply it to our proposed new architecture on a spin-fermion model on a\ntwo-dimensional lattice. We find that it overcomes poor acceptance rates for\nlinear models and observe the scaling law of the acceptance rate as in the\nlarge language models with Transformers.",
        "positive": "On the renormalization of the Polyakov loop: We discuss a non-perturbative renormalization of n-point Polyakov loop\ncorrelation functions by explicitly introducing a renormalization constant for\nthe Polyakov loop operator on a lattice deduced from the short distance\nproperties of 2-point correlators. We calculate this constant for the\nSU(3)gauge theory."
    },
    {
        "anchor": "Lattice calculation of isospin corrections to Kl2 and Kl3 decays: In this talk I discuss the theoretical issues associated with lattice\ncalculations of isospin breaking corrections to hadronic matrix elements. I\nconcentrate on the calculation of QCD isospin breaking effects for the Kl2 and\nKl3 decay rates and illustrate the recent lattice results obtained by the RM123\ncollaboration.",
        "positive": "Singular values of the Dirac operator at nonzero density: At nonzero density the eigenvalues of the Dirac operator move into the\ncomplex plane, while its singular values remain real and nonnegative. In\nQCD-like theories, the singular-value spectrum carries information on the\ndiquark (or pionic) condensate. We have constructed low-energy effective\ntheories in different density regimes and derived a number of exact results for\nthe Dirac singular values, including Banks-Casher-type relations for the\ndiquark (or pionic) condensate, Smilga-Stern-type relations for the slope of\nthe singular-value density, and Leutwyler-Smilga-type sum rules for the inverse\nsingular values. We also present a rigorous index theorem for non-Hermitian\nDirac operators."
    },
    {
        "anchor": "Lattice Approach to Light Scalars: I report on lattice QCD calculations that study the properties of the a0 and\nf0 mesons.",
        "positive": "Schwinger-Keldysh on the lattice: a faster algorithm and its application\n  to field theory: A new algorithm is developed allowing the Monte Carlo study of a 1 + 1\ndimensional theory in real time. The main algorithmic development is to avoid\nthe explicit calculation of the Jacobian matrix and its determinant in the\nupdate process. This improvement has a wide applicability and reduces the cost\nof the update in thimble-inspired calculations from O(N^3) to less than O(N^2).\nAs an additional feature, the algorithm leads to improved Monte Carlo\nproposals. We exemplify the use of the algorithm to the real time dynamics of a\nscalar {\\phi}^4 theory with weak and strong couplings."
    },
    {
        "anchor": "Nucleon structure with dynamical (2+1)-flavor domain wall fermions\n  lattice QCD: We report isovector form factors and low moments of isovector structure\nfunctions of nucleon from the coarse RIKEN-BNL-Columbia (RBC) and UKQCD joint\ndynamical (2+1)-flavor domain-wall fermions (DWF) ensembles. The lattice cut\noff is estimated at (a^{-1}=1.7) GeV. The lattice volume is as large as 2.7 fm\nacross. We carefully optimize the nucleon source/sink separation in time to\nabout 1.4 fm. Unexpectedly large finite-size effect in the axial charge is\nfound. The effect scales with a single variable, the product (m_\\pi L) of the\npion mass (m_\\pi) and lattice spatial linear extent (L), and sets in at around\n(m_\\pi L = 5). We also discuss momentum-transfer dependence of the vector,\ninduced tensor, axial-vector and induced pesudo-scalar form factors.\n  From structure functions, fully non-perturbatively renormalized iso-vector\nquark momentum fraction, (< x >_{u-d}), helicity fraction, (< x >_{\\Delta u -\n\\Delta d}), and transversity, (< 1 >_{\\delta u - \\delta d}), are reported, as\nwell as an unrenormalized twist-3 coefficient, (d_1). The ratio of the momentum\nto helicity fractions, (< x >_{u-d}/< x >_{\\Delta u - \\Delta d}), does not\ndepend on light quark mass and agree well with the experiment. Their respective\nabsolute values, fully renormalized, shows interesting trending toward the\nrespective experimental values at the lightest light quark mass.",
        "positive": "The Optical Potential on the Lattice: The extraction of hadron-hadron scattering parameters from lattice data by\nusing the L\\\"uscher approach becomes increasingly complicated in the presence\nof inelastic channels. We propose a method for the direct extraction of the\ncomplex hadron-hadron optical potential on the lattice, which does not require\nthe use of the multi-channel L\\\"uscher formalism. Moreover, this method is\napplicable without modifications if some inelastic channels contain three or\nmore particles."
    },
    {
        "anchor": "Improved non-perturbative renormalization without $c_{NGI}$: Recently, a method for O(a) improvement of composite operators has been\nproposed which uses the large momentum behavior of fixed gauge quark and gluon\ncorrelation functions (G. Martinelli et al., hep-lat/0106003). A practical\nproblem with this method is that a particular improvement coefficient,\n$c_{NGI}$, which has a gauge non-covariant form, is difficult to determine.\nHere I work out the size of the errors made in improvement coefficients and\nphysical quantities if one does not include the $c_{NGI}$ term.",
        "positive": "Gauge invariance of the Abelian dual Meissner effect in pure SU(2) QCD: The dual Meissner effect is described and numerically observed in a\ngauge-invariant way in lattice Monte-Carlo simulations in pure SU(2) QCD. The\nsqueezing of the non-Abelian electric field between a pair of static quark and\nanti-quark occurs due to the solenoidal current coming from the gauge-invariant\nmonopole-like quantity. Preliminary results are obtained with respect to the\nvacuum type of the confinement phase. The SU(2) QCD vacuum seems near the\nborder between the type 1 and the type 2 dual superconductors. The theoretical\nbackground of this idea is published in another report\n\\cite{Suzuki:2005lat051}. Here we show numerical results in this note."
    },
    {
        "anchor": "Confinement without a center: the exceptional group G(2): We discuss theories with the exceptional centerless gauge group G(2), paying\nattention to confinement and the pattern of chiral symmetry breaking.\nExploiting the Higgs mechanism to break the symmetry down to SU(3), we also\npresent how the familiar features of confinement and chiral symmetry breaking\nof SU(3) gauge theories reemerge. G(2) gauge theories show up as an unusual\ntheoretical framework to study SU(3) gauge theories without the ``luxury'' of a\ncenter.",
        "positive": "Poisson statistics in the high temperature QCD Dirac spectrum: We analyze the eigenvalue statistics of the staggered Dirac operator above\n$T_{c}$ in QCD with 2+1 flavors of dynamical quarks. We use physical quark\nmasses in our simulations. We compare the eigenvalue statistics from several\nparts of the Dirac spectrum with the predictions of Random Matrix Theory for\nthis universality class and with Poisson statistics. We show that at the low\nend of the spectrum the eigenmodes are localized and obey Poisson statistics.\nAbove a boundary region the eigenmodes become delocalized and obey Random\nMatrix statistics. Thus the QCD Dirac spectrum with physical dynamical quarks\nalso has the Poisson to Random Matrix transition previously seen in the\nquenched SU(2) theory."
    },
    {
        "anchor": "Deconfinement in Yang-Mills: a conjecture for a general gauge Lie group\n  G: Svetitsky and Yaffe have argued that -- if the deconfinement phase transition\nof a (d+1)-dimensional Yang-Mills theory with gauge group G is second order --\nit should be in the universality class of a d-dimensional scalar model\nsymmetric under the center C(G) of G. These arguments have been investigated\nnumerically only considering Yang-Mills theory with gauge symmetry in the\nG=SU(N) branch, where C(G)=Z(N). The symplectic groups Sp(N) provide another\nextension of SU(2)=Sp(1) to general N and they all have the same center Z(2).\nHence, in contrast to the SU(N) case, Sp(N) Yang-Mills theory allows to study\nthe relevance of the group size on the order of the deconfinement phase\ntransition keeping the available universality class fixed. Using lattice\nsimulations, we present numerical results for the deconfinement phase\ntransition in Sp(2) and Sp(3) Yang-Mills theories both in (2+1)d and (3+1)d. We\nthen make a conjecture on the order of the deconfinement phase transition in\nYang-Mills theories with general Lie groups SU(N), SO(N), Sp(N) and with\nexceptional groups G(2), F(4), E(6), E(7), E(8). Numerical results for G(2)\nYang-Mills theory at finite temperature in (3+1)d are also presented.",
        "positive": "Fermionic topological charge of families of lattice gauge fields: Topological charge of families of lattice gauge fields is defined\nfermionically via families index theory for the overlap Dirac operator. Certain\nobstructions to gauge invariance of the overlap chiral fermion determinant, as\nwell as the lattice analogues of certain obstructions to gauge fixings without\nthe Gribov problem, have natural descriptions in this context."
    },
    {
        "anchor": "Lattice renormalization of the static quark derivative operator: We give the analytical expressions and numerical values of radiative\ncorrections to the covariant derivative operator on the static quark line, used\nfor the lattice calculation of the Isgur-Wise form factors $\\tau_{1/2}(1)$ and\n$\\tau_{3/2}(1)$. Those corrections induce an enhancement of renormalized\nquantities if an hypercubic blocking is applied to the Wilson line, whereas\nthere is a reduction without such a blocking.",
        "positive": "Lattice gauge action suppressing near-zero modes of H_W: We propose a lattice action including unphysical Wilson fermions with a\nnegative mass m_0 of the order of the inverse lattice spacing. With this\naction, the exact zero mode of the hermitian Wilson-Dirac operator H_W(m_0)\ncannot appear and near-zero modes are strongly suppressed. By measuring the\nspectral density rho(lambda_W), we find a gap near lambda_W=0 on the\nconfigurations generated with the standard and improved gauge actions. This gap\nprovides a necessary condition for the proof of the exponential locality of the\noverlap-Dirac operator by Hernandez, Jansen, and Luescher. Since the number of\nnear-zero modes is small, the numerical cost to calculate the matrix sign\nfunction of H_W(m_0) is significantly reduced, and the simulation including\ndynamical overlap fermions becomes feasible. We also introduce a pair of\ntwisted mass pseudo-fermions to cancel the unwanted higher mode effects of the\nWilson fermions. The gauge coupling renormalization due to the additional\nfields is then minimized. The topological charge measured through the index of\nthe overlap-Dirac operator is conserved during continuous evolutions of gauge\nfield variables."
    },
    {
        "anchor": "The Schrodinger functional with chirally rotated boundary conditions: Using orbifold techniques I construct the Schrodinger functional (SF) for a\ndoublet of Wilson quarks with chirally rotated boundary conditions. This allows\nto perform checks of universality: for instance, the renormalized SF coupling\nconstant, defined with either boundary conditions, must have a unique continuum\nlimit. Similarly, SF correlation functions in twisted mass QCD and standard QCD\ncan be defined such that they share a common continuum limit. An additional\nbenefit of the new set-up consists in the observation that all the bulk O(a)\ncounterterms to the action and composite operators become irrelevant in the\nchiral limit. This implies that (ratios of) SF renormalization constants can be\nautomatically O(a) improved, up to the effect of unavoidable boundary\ncounterterms. As a first application we calculate the running coupling for Nf=2\nflavours in the SF-scheme to one-loop order of perturbation theory.\nUniversality of the continuum limit is confirmed and the irrelevance of the\nSheikholeslami-Wohlert term in the action is demonstrated explicitly",
        "positive": "Matrix elements of heavy-light mesons from a fine lattice: Results on semileptonic decay matrix elements of heavy-light mesons and\ncharmonium spectrum and decay constant using a fine quenched lattice are\npresented."
    },
    {
        "anchor": "Two-loop Sunset Integrals at Finite Volume: We show how to compute the two-loop sunset integrals at finite volume, for\nnon-degenerate masses and non-zero momentum. We present results for all\nintegrals that appear in the Chiral Perturbation Therory ($\\chi$PT) calculation\nof the pseudoscalar meson masses and decay constants at NNLO, including the\ncase of Partially Quenched $\\chi$PT. We also provide numerical implementations\nof the finite-volume sunset integrals, and review the results for one-loop\nintegrals at finite volume.",
        "positive": "Reducing finite-size effects with reweighted renormalization group\n  transformations: We combine histogram reweighting techniques with the two-lattice matching\nMonte Carlo renormalization group method to conduct computationally efficient\ncalculations of critical exponents on systems with moderately small lattice\nsizes. The approach, which relies on the construction of renormalization group\nmappings between two systems of identical lattice size to partially eliminate\nfinite-size effects, and the use of histogram reweighting to obtain\ncomputationally efficient results in extended regions of parameter space, is\nutilized to explicitly determine the renormalized coupling parameters of the\ntwo-dimensional $\\phi^{4}$ scalar field theory and to extract multiple critical\nexponents. We conclude by quantifying the computational benefits of the\napproach and discuss how reweighting opens up the opportunity to extend Monte\nCarlo renormalization group methods to systems with complex-valued actions."
    },
    {
        "anchor": "Bottomonium above deconfinement in lattice nonrelativistic QCD: We study the temperature dependence of bottomonium for temperatures in the\nrange $0.4 T_c < T < 2.1 T_c$, using nonrelativistic dynamics for the bottom\nquark and full relativistic lattice QCD simulations for $N_f=2$ light flavors\non a highly anisotropic lattice. We find that the $\\Upsilon$ is insensitive to\nthe temperature in this range, while the $\\chi_b$ propagators show a crossover\nfrom the exponential decay characterizing the hadronic phase to a power-law\nbehaviour consistent with nearly-free dynamics at $T \\simeq 2 T_c$.",
        "positive": "Interacting staggered domain wall fermions: The behavior of staggered domain wall fermions in the presence of gauge\nfields is presented. In particular, their response to gauge fields with\nnontrivial topology is discussed."
    },
    {
        "anchor": "Perturbative calculation of improvement coefficients to O(g^2a) for\n  bilinear quark operators in lattice QCD: We calculate the O(g^2 a) mixing coefficients of bilinear quark operators in\nlattice QCD using a standard perturbative evaluation of on-shell Green's\nfunctions. Our results for the plaquette gluon action are in agreement with\nthose previously obtained with the Schr\\\"odinger functional method. The\ncoefficients are also calculated for a class of improved gluon actions having\nsix-link terms.",
        "positive": "Isolating the Roper Resonance in Lattice QCD: We present results for the first positive parity excited state of the\nnucleon, namely, the Roper resonance ($N^{{{1/2}}^{+}}$=1440 MeV) from a\nvariational analysis technique. The analysis is performed for pion masses as\nlow as 224 MeV in quenched QCD with the FLIC fermion action. A wide variety of\nsmeared-smeared correlation functions are used to construct correlation\nmatrices. This is done in order to find a suitable basis of operators for the\nvariational analysis such that eigenstates of the QCD Hamiltonian may be\nisolated. A lower lying Roper state is observed that approaches the physical\nRoper state.\n  To the best of our knowledge, the first time this state has been identified\nat light quark masses using a variational approach."
    },
    {
        "anchor": "Electromagnetic mass difference on the lattice: We calculate electromagnetic mass difference of mesons using a method\nproposed by Duncan {\\it et al}. The RG-improved gauge action and the\nnon-compact Abelian gauge action are employed to generate configurations. Quark\npropagators in the range of $m_{PS}/m_{V}=0.76-0.51$ are obtained with the\nmeanfield-improved clover quark action. Chiral and continuum extrapolations are\nperformed and the results are compared with experiments. Finite size effects\nare also examined. Quark masses are extracted from the measured spectrum. Our\npreliminary values for light quark masses are $m_{u}^{\\bar{MS}}(\\mu =2 {GeV}) =\n3.03(19)$ MeV, $m_{d}^{\\bar{MS}}(\\mu = 2 {GeV}) = 4.44(28)$ MeV,\n$m_{s}^{\\bar{MS}}(\\mu = 2 {GeV}) = 99.2(52)$ MeV.",
        "positive": "Getting Around the Nielsen-Ninomiya Theorem, towards the Rome Approach: The ``no-go'' theorem of Nielsen and Ninomiya has been the most tenacious\nobstacle against the construction of a chiral gauge theory with reasonable low\nenergy spectrum, couplings and anomaly. In this paper we construct a model\nwhich supplements the usual (bilinear in the Fermi fields) lagrangian with\nquadrilinear fermionic terms. We show that in a certain region of the parameter\nspace the difficulties of the ``no-go'' theorem may be overcome, and a\n``renormalized'' perturbative strategy can be carried out, akin to the one\nfollowed in the Rome Approach (RA), whose counterterms are forced to be gauge\ninvariant."
    },
    {
        "anchor": "String effects in Polyakov loop correlators: We compare the predictions of the effective string description of confinement\nin finite temperature gauge theories to high precision Monte Carlo data for the\nthree-dimensional Z(2) gauge theory. We show that string interaction effects\nbecome more relevant as the temperature is increased towards the deconfinement\none, and are well modeled by a Nambu-Goto string action.",
        "positive": "4D $\\mathcal{N}=1$ SYM supercurrent on the lattice in terms of the\n  gradient flow: The gradient flow[1-5] gives rise to a versatile method to construct\nrenormalized composite operators in a regularization-independent manner. By\nadopting this method, the authors of~Refs.[6-9] obtained the expression of\nNoether currents on the lattice in the cases where the associated symmetries\nare broken by lattice regularization. We apply the same method to the Noether\ncurrent associated with supersymmetry, i.e., the supercurrent. We consider the\n4D $\\mathcal{N}=1$ super Yang--Mills theory and calculate the renormalized\nsupercurrent in the one-loop level in the Wess--Zumino gauge. We then\nre-express this supercurrent in terms of the flowed gauge and flowed gaugino\nfields[10]."
    },
    {
        "anchor": "Complex Langevin simulations for $PT$-symmetric models: Self-interacting scalar quantum field theories possessing $PT$-symmetry are\nphysically admissible since their energy spectrum is real and bounded below.\nHowever, models with $PT$-invariant potentials can have complex actions in\ngeneral and a non-perturbative study of such systems using methods based on\ntraditional Monte Carlo is hindered due to numerical sign problem. In this work\nwe employ complex Langevin based on stochastic quantization to study\ntwo-dimensional scalar field theories, including the ones exhibiting\n$PT$-symmetry. We also study the simplest supersymmetric version of these\nsystems and address the question on dynamical supersymmetry breaking.",
        "positive": "Separation-of-charge confinement and the Higgs transition in SU(3) gauge\n  Higgs theory: With SU(3) gauge Higgs theory as an example, we examine critically the idea\nthat the confinement property in an SU(N) gauge-Higgs theory, with the Higgs\nfield in the fundamental representation, persists in an unbroken SU(N-1)\nsubgroup."
    },
    {
        "anchor": "Lattice QCD with QCDLAB: QCDLAB is a set of programs, written in GNU Octave, for lattice QCD\ncomputations. Version 2.0 includes the generation of configurations for the\nSU(3) theory, computation of rectangle Wilson loops as well as the low lying\nmeson spectrum with Wilson fermions. Version 2.1 includes also the computation\nof the low lying meson spectrum using minimally doubled chiral fermions. In\nthis paper, we give a brief tutorial on lattice QCD computations using QCDLAB.",
        "positive": "Axial U(1) symmetry and Dirac spectra in high-temperature phase of\n  $N_f=2$ lattice QCD: The axial $U(1)$ symmetry in the high-temperature phase is investigated with\n$N_f = 2$ lattice QCD simulations. The gauge ensembles are generated with\nM\\\"obius domain-wall fermions, and the overlap/domain-wall reweighting is\napplied. We find that the $U(1)_A$ susceptibility evaluated from the spectrum\nof overlap-Dirac eigenvalues is strongly suppressed in the chiral limit. We\nalso study its volume dependence."
    },
    {
        "anchor": "Overlap Fermion in External Gravity: On a lattice, we construct an overlap Dirac operator which describes the\npropagation of a Dirac fermion in external gravity. The local Lorentz symmetry\nis manifestly realized as a lattice gauge symmetry, while the general\ncoordinate invariance is expected to be restored only in the continuum limit.\nThe lattice index density in the presence of a gravitational field is\ncalculated.",
        "positive": "Twisted mass chiral perturbation theory for 2+1+1 quark flavours: We present results for the masses of pseudoscalar mesons in twisted mass\nlattice QCD with a degenerate doublet of u and d quarks and a non-degenerate\ndoublet of s and c quarks in the framework of next-to-leading order chiral\nperturbation theory, including lattice effects up to O(a^2). The masses depend\non the two twist angles for the light and heavy sectors. For maximal twist in\nboth sectors, O(a)-improvement is explicitly exhibited. The mixing of\nflavour-neutral mesons is also discussed, and results in the literature for the\ncase of degenerate s and c quarks are corrected."
    },
    {
        "anchor": "Vortex Dynamics in Classical Non--Abelian Spin Models: We discuss the abelian vortex dynamics in the abelian projection approach to\nnon-abelian spin models. We show numerically that in the three-dimensional\nSU(2) spin model in the Maximal Abelian projection the abelian off-diagonal\nvortices are not responsible for the phase transition contrary to the diagonal\nvortices. A generalization of the abelian projection approach to SU(N) spin\nmodels is briefly discussed.",
        "positive": "A new approach to noncompact lattice qed with light fermions: We discuss detailed simulations of the non compact abelian model coupled to\nlight fermions, using a method previously developed that includes the effects\nof the fermionic interactions in an effective action. The approximations\ninvolved are related to an expansion in the flavour number. We address the\nproblem of the (non) triviality of the theory through a study of the analytical\nproperties of the effective action as a function of the pure gauge energy. New\nnumerical results for the plaquette energy, chiral condensate and a qualitative\nanalysis of the phase diagram are also presented."
    },
    {
        "anchor": "Electric polarizability of the neutron in dynamical quark ensembles: The background field method for measuring the electric polarizability of the\nneutron is adapted to the dynamical quark case, resulting in the calculation of\n(certain space-time integrals over) three- and four-point functions. Particular\ncare is taken to disentangle polarizability effects from the effects of\nsubjecting the neutron to a constant background gauge field; such a field is\nnot a pure gauge on a finite lattice and engenders a mass shift of its own. At\na pion mass of m_pi = 759 MeV, a small, slightly negative electric\npolarizability is found for the neutron.",
        "positive": "The size of the pion from full lattice QCD with physical $u$, $d$, $s$\n  and $c$ quarks: We present the first calculation of the electromagnetic form factor of the\n$\\pi$ meson at physical light quark masses. We use configurations generated by\nthe MILC collaboration including the effect of $u$, $d$, $s$ and $c$ sea quarks\nwith the Highly Improved Staggered Quark formalism. We work at three values of\nthe lattice spacing on large volumes and with $u$/$d$ quark masses going down\nto the physical value. We study scalar and vector form factors for a range in\nspace-like $q^2$ from 0.0 to -0.1 $\\mathrm{GeV}^2$ and from their shape we\nextract mean square radii. Our vector form factor agrees well with experiment\nand we find $\\langle r^2 \\rangle_V = 0.403(18)(6) \\,\\mathrm{fm}^2$. For the\nscalar form factor we include quark-line disconnected contributions which have\na significant impact on the radius. We give the first results for SU(3)\nflavour-singlet and octet scalar mean square radii, obtaining: $\\langle r^2\n\\rangle_S^{\\mathrm{singlet}} = 0.506(38)(53) \\mathrm{fm}^2$ and $\\langle r^2\n\\rangle_S^{\\mathrm{octet}} = 0.431(38)(46) \\mathrm{fm}^2$. We discuss the\ncomparison with expectations from chiral perturbation theory."
    },
    {
        "anchor": "Topology in the SU(N_f) chiral symmetry restored phase of unquenched QCD\n  and axion cosmology II: We investigate the physical consequences of the survival of the effects of\nthe U(1)_A anomaly in the chiral symmetric phase of QCD, and show that the free\nenergy density is a singular function of the quark mass m, in the chiral limit,\nand that the $\\sigma$ and $\\bar\\pi$ susceptibilities diverge in this limit at\nany $T\\ge T_c$. We also show that the difference between the $\\bar\\pi$ and\n$\\bar\\delta$ susceptibilities diverges in the chiral limit at any $T\\ge T_c$, a\nresult which seems to be excluded by recent results of Tomiya et al. from\nnumerical simulations of two-flavor QCD. We also discuss on the generalization\nof these results to the $N_f\\ge 3$ model.",
        "positive": "Current correlators in the coordinate space at short distances: We calculate the vector and axial-vector current correlators in the\ncoordinate space and compare them with the experimental information obtained\nthrough the spectral functions of hadronic tau decays measured by ALEPH.\nLattice data are obtained with 2+1 Mobius domain-wall fermions at three lattice\nspacings 0.044, 0.055 and 0.080 fm and the continuum limit is taken. The\ncorrelators calculated on the lattice after extrapolating to the physical point\nagree with those converted from the ALEPH data."
    },
    {
        "anchor": "Potts Flux Tube Model at Nonzero Chemical Potential: We model the deconfinement phase transition in quantum chromodynamics at\nnonzero baryon number density and large quark mass by extending the flux tube\nmodel (three-state, three-dimensional Potts model) to nonzero chemical\npotential. In a direct numerical simulation we confirm mean-field-theory\npredictions that the deconfinement transition does not occur in a baryon-rich\nenvironment.",
        "positive": "A New Method of Calculating the Running Coupling Constant: We propose a new method to compute the running coupling constant of gauge\ntheories on the lattice. We first give the definition of the running coupling\nin the new scheme using the Wilson loops in a finite volume, and explain how\nthe running of the coupling constant is extracted from the measurement of the\nvolume dependence. The perturbative calculation of the renormalization constant\nto define the scheme is also given at the leading order. As a benchmark test of\nthe new scheme we apply the method the case of the quenched QCD. We show the\npreliminary result from our numerical simulations which are carried out with\nplaquette gauge action for various lattice sizes and bare lattice couplings.\nWith techniques to improve the statistical accuracy, we show that we can\ndetermine the non-perturbative running of the coupling constant in a wide range\nof the energy scale with relatively small number of gauge configurations in our\nscheme. We compare our lattice data of the running coupling constant with\nperturbative renormalization group evolution at one- and two-loop order, and\nconfirm the consistency between them at high energy."
    },
    {
        "anchor": "Heavy Quark Anti-Quark Free Energy and the Renormalized Polyakov Loop: We calculate the colour averaged and colour singlet free energies of static\nquark anti-quark sources placed in a thermal gluonic heat bath. We discuss the\nrenormalization of these free energies using the short distance properties of\nthe zero temperature heavy quark potential. This leads to the definition of the\nrenormalized Polyakov loop as an order parameter for the deconfinement phase\ntransition of the SU(3) gauge theory which is well behaved in the continuum\nlimit.",
        "positive": "Perturbative expansion of the energy of static sources at large orders\n  in four-dimensional SU(3) gauge theory: We determine the infinite volume coefficients of the perturbative expansions\nof the self-energies of static sources in the fundamental and adjoint\nrepresentations in SU(3) gluodynamics to order \\alpha^{20} in the strong\ncoupling parameter \\alpha. We use numerical stochastic perturbation theory,\nwhere we employ a new second order integrator and twisted boundary conditions.\nThe expansions are obtained in lattice regularization with the Wilson action\nand two different discretizations of the covariant time derivative within the\nPolyakov loop. Overall, we obtain four different perturbative series. For all\nof them the high order coefficients display the factorial growth predicted by\nthe conjectured renormalon picture, based on the operator product expansion.\nThis enables us to determine the normalization constants of the leading\ninfrared renormalons of heavy quark and heavy gluino pole masses and to\ntranslate these into the modified minimal subtraction scheme (MS). We also\nestimate the four-loop \\beta-function coefficient of the lattice scheme."
    },
    {
        "anchor": "Volume scaling of Dirac eigenvalues in SU(3) lattice gauge theory with\n  color sextet fermions: I observe a rough volume-dependent scaling of the low eigenvalues of a chiral\nDirac operator in lattice studies of SU(3) lattice gauge theory with two\nflavors of color sextet fermions, in its weak-coupling phase. The mean value of\nthe ith eigenvalue scales with the simulation volume V=L^4 as <lambda_i>L^p\n~zeta_i, where zeta_i is a volume-independent constant. The exponent p is about\n1.4. A possible explanation for this phenomenon is that p is the leading\nrelevant exponent associated with the fermion mass dependence of correlation\nfunctions in a theory whose zero-mass limit is conformal.",
        "positive": "Hyperon-Nucleon Scattering from Fully-Dynamical Lattice QCD: We present results of the first fully-dynamical lattice QCD determination of\nhyperon-nucleon scattering. One s-wave phase shift was determined for n Lambda\nscattering in both spin-channels at pion masses of 350, 490, and 590 MeV, and\nfor n Sigma- scattering in both spin channels at pion masses of 490, and 590\nMeV. The calculations were performed with domain-wall valence quarks on\ndynamical, staggered gauge configurations with a lattice spacing of b ~ 0.125\nfm."
    },
    {
        "anchor": "Towards the chiral phase transition in the Roberge-Weiss plane: We discuss the interplay between chiral and center sector phase transitions\nthat occur in QCD with an imaginary quark chemical potential $\\mu=i(2n+1) \\pi\nT/3$. Based on a finite size scaling analysis in (2+1)-flavor QCD using HISQ\nfermions with a physical strange quark mass and a range of light quark masses,\nwe show that the endpoint of the line of first-order Roberge-Weiss (RW)\ntransitions between center sectors is second order for light quark masses\n$m_l\\ge m_s/320$, and that it belongs to the $3$-d, $Z(2)$ universality class.\nThe operator for the chiral condensate behaves like an energy-like operator in\nan effective spin model for the RW phase transition. As a consequence, for any\nnon-zero value of the quark mass, the chiral condensate will have an infinite\nslope at the RW phase transition temperature, $T_{RW}$. Its fluctuation, the\ndisconnected chiral susceptibility, behaves like the specific heat in $Z(2)$\nsymmetric models and diverges in the infinite volume limit at the RW phase\ntransition temperature $T_{RW}$ for any non-zero value of the light quark\nmasses. Our analysis suggests the critical temperatures for the RW phase\ntransition and the chiral phase transition coincide in the RW plane. On\nlattices with temporal extent $N_\\tau=4$, we find in the chiral limit\n$T_{\\chi}=T_{RW}=195(1)~$MeV.",
        "positive": "Hadronic form factors in Lattice QCD at small and vanishing momentum\n  transfer: The introduction of partially twisted boundary conditions allows weak and\nelectromagnetic form factors to be evaluated at specified values of the\nhadronic momenta (and hence momentum transfers) in lattice simulations. We\npresent and demonstrate this technique for the computation of the K->pi\nsemileptonic form factor at zero momentum transfer and for the electromagnetic\nform factor of the pion at arbitrarily small momentum transfers. These\nexploratory computations are carried out in full QCD with 3 flavours of sea\nquarks, but with only two values of m_u=m_d which limits our ability to perform\nthe chiral extrapolations. The results should therefore be viewed primarily as\na demonstration of the feasibility of the method. For the K-> pi form factor we\ncompare the new technique to the conventional approach and for the pion form\nfactor we assess our results for very small momentum transfer with the help of\nchiral perturbation theory."
    },
    {
        "anchor": "Introduction of the chemical potential in the overlap formalism: We investigate the possibility of coupling a chemical potential only to the\nphysical chiral fermions on the lattice starting from the many body state\ndescription of overlap fermions. After developing the formalism for a chiral\ngauge theory, we focus our attention on the case of free fermions coupled to a\nvector like chemical potential and discuss the issue of zero temperature\ndivergences.",
        "positive": "Pion decay constant for the Kogut-Susskind quark action in quenched\n  lattice QCD: We present a study for the pion decay constant $f_\\pi$ in the quenched\napproximation to lattice QCD with the Kogut-Susskind (KS) quark action, with\nthe emphasis given to the renormalization problems. Numerical simulations are\ncarried out at the couplings $\\beta = 6.0$ and 6.2 on $32^3\\times 64$ and\n$48^3\\times 64$ lattices, respectively. The pion decay constant is evaluated\nfor all KS flavors via gauge invariant and non-invariant axial vector currents\nwith the renormalization constants calculated by both non-perturbative method\nand perturbation theory. We obtain $f_\\pi = 89(6)$ MeV in the continuum limit\nas the best value using the partially conserved axial vector current, which\nrequires no renormalization. From a study for the other KS flavors we find that\nthe results obtained with the non-perturbative renormalization constants are\nwell convergent among the KS flavors in the continuum limit, confirming\nrestoration of $\\rm SU(4)_A$ flavor symmetry, while perturbative\nrenormalization still leaves an apparent flavor breaking effect even in the\ncontinuum limit."
    },
    {
        "anchor": "Nucleon Structure in Lattice QCD using twisted mass fermions: We present results on the nucleon form factors and moments of generalized\nparton distributions obtained within the twisted mass formulation of lattice\nQCD. We include a discussion of lattice artifacts by examining results at\ndifferent volumes and lattice spacings. We compare our results with those\nobtained using different discretization schemes and to experiment.",
        "positive": "Over-Improved Stout-Link Smearing: A new over-improved stout-link smearing algorithm, designed to stabilise\ninstanton-like objects, is presented. A method for quantifying the selection of\nthe over-improvement parameter, $\\epsilon$, is demonstrated. The new smearing\nalgorithm is compared with the original stout-link smearing, and Symanzik\nimproved smearing through calculations of the topological charge and\nvisualisations of the topological charge density."
    },
    {
        "anchor": "Baryon-Baryon Interactions and Spin-Flavor Symmetry from Lattice Quantum\n  Chromodynamics: Lattice quantum chromodynamics is used to constrain the interactions of two\noctet baryons at the SU(3) flavor-symmetric point, with quark masses that are\nheavier than those in nature (equal to that of the physical strange quark mass\nand corresponding to a pion mass of $\\approx 806~\\tt{MeV}$). Specifically, the\nS-wave scattering phase shifts of two-baryon systems at low energies are\nobtained with the application of L\\\"uscher's formalism, mapping the energy\neigenvalues of two interacting baryons in a finite volume to the two-particle\nscattering amplitudes below the relevant inelastic thresholds. The values of\nthe leading-order low-energy scattering parameters in the irreducible\nrepresentations of SU(3) are consistent with an approximate SU(6) spin-flavor\nsymmetry in the nuclear and hypernuclear forces that is predicted in the\nlarge-$N_c$ limit of QCD. The two distinct SU(6)-invariant interactions between\ntwo baryons are constrained at this value of the quark masses, and their values\nindicate an approximate accidental SU(16) symmetry. The SU(3) irreducible\nrepresentations containing the $NN~({^1}S_0)$, $NN~({^3}S_1)$ and\n$\\frac{1}{\\sqrt{2}}(\\Xi^0n+\\Xi^-p)~({^3}S_1)$ channels unambiguously exhibit a\nsingle bound state, while the irreducible representation containing the\n$\\Sigma^+ p~({^3}S_1)$ channel exhibits a state that is consistent with either\na bound state or a scattering state close to threshold. These results are in\nagreement with the previous conclusions of the NPLQCD collaboration regarding\nthe existence of two-nucleon bound states at this value of the quark masses.",
        "positive": "Pion mass dependence of the nucleon mass in the chiral quark soliton\n  model: The dependence of the nucleon mass on the mass of the pion is studied in the\nframework of the chiral quark-soliton model. A remarkable agreement is observed\nwith lattice data from recent full dynamical simulations. The possibility and\nlimitations to use the model results as a guideline for the chiral\nextrapolation of lattice data are discussed."
    },
    {
        "anchor": "Heavy Quarks on Anisotropic Lattices: The Charmonium Spectrum: We present results for the mass spectrum of $c{\\bar c}$ mesons simulated on\nanisotropic lattices where the temporal spacing $a_t$ is only half of the\nspatial spacing $a_s$. The lattice QCD action is the Wilson gauge action plus\nthe clover-improved Wilson fermion action. The two clover coefficients on an\nanisotropic lattice are estimated using mean links in Landau gauge. The bare\nvelocity of light $\\nu_t$ has been tuned to keep the anisotropic, heavy-quark\nWilson action relativistic. Local meson operators and three box sources are\nused in obtaining clear statistics for the lowest lying and first excited\ncharmonium states of $^1S_0$, $^3S_1$, $^1P_1$, $^3P_0$ and $^3P_1$. The\ncontinuum limit is discussed by extrapolating from quenched simulations at four\nlattice spacings in the range 0.1 - 0.3 fm. Results are compared with the\nobserved values in nature and other lattice approaches. Finite volume effects\nand dispersion relations are checked.",
        "positive": "Results from a Non-Perturbative Renormalization of Lattice Operators: We propose a general renormalization method, which avoids completely the use\nof lattice perturbation theory. We present the results from its numerical\napplications to two-fermion operators on a $16^3 \\times 32$ lattice, at\n$\\beta=6.0$."
    },
    {
        "anchor": "Color Screening by Pions: Lattice QCD is used to calculate the potential between a static quark and\nanti-quark in the presence of a finite density of pi^+'s. Correlation functions\nof multiple pi^+'s are used in conjunction with Wilson-loop correlators to\ndetermine the difference between the Q\\overline{Q}-potential in free-space and\nin the presence of a pion condensate. The modifications to the potential are\nfound to have significant dependence on the Q\\overline{Q} separation over the\nrange r < 1 fm explored in this work. Our results are consistent with the\npion-condensate behaving as a (nonlinear) chromo-dielectric.",
        "positive": "Chern-Simons term and Topological Charge on the Lattice: In a somewhat overlooked work by Seiberg, a definition of the topological\ncharge for SU(N) lattice fields was given. Here, it is shown that Seibergs and\nL\\\"{u}schers charge definition are related up to the section of the bundle.\nWith the continued interest in baryon number violating processes, Seibergs\npaper is useful since it allows for a Chern-Simons number also."
    },
    {
        "anchor": "$\u03b8$ dependence of 4D $SU(N)$ gauge theories in the large-$N$ limit: We study the large-$N$ scaling behavior of the $\\theta$ dependence of the\nground-state energy density $E(\\theta)$ of four-dimensional (4D) $SU(N)$ gauge\ntheories and two-dimensional (2D) $CP^{N-1}$ models, where $\\theta$ is the\nparameter associated with the Lagrangian topological term. We consider its\n$\\theta$ expansion around $\\theta=0$, $E(\\theta)-E(0) = {1\\over 2}\\chi\n\\,\\theta^2 ( 1 + b_2 \\theta^2 + b_4\\theta^4 +\\cdots)$ where $\\chi$ is the\ntopological susceptibility and $b_{2n}$ are dimensionless coefficients. We\nfocus on the first few coefficients $b_{2n}$, which parametrize the deviation\nfrom a simple Gaussian distribution of the topological charge at $\\theta=0$. We\npresent a numerical analysis of Monte Carlo simulations of 4D $SU(N)$ lattice\ngauge theories for $N=3,\\,4,\\,6$ in the presence of an imaginary $\\theta$ term.\nThe results provide a robust evidence of the large-$N$ behavior predicted by\nstandard large-$N$ scaling arguments, i.e. $b_{2n}= O(N^{-2n})$. In particular,\nwe obtain $b_2=\\bar{b}_2/N^2 + O(1/N^4)$ with $\\bar{b}_2=-0.23(3)$. We also\nshow that the large-$N$ scaling scenario applies to 2D $CP^{N-1}$ models as\nwell, by an analytic computation of the leading large-$N$ dependence.",
        "positive": "Decay Constants of Pseudoscalar $D$-mesons in Lattice QCD with\n  Domain-Wall Fermion: We present the first study of the masses and decay constants of the\npseudoscalar $ D $ mesons in two flavors lattice QCD with domain-wall fermion.\nThe gauge ensembles are generated on the $24^3 \\times 48 $ lattice with the\nextent $ N_s = 16 $ in the fifth dimension, and the plaquette gauge action at $\n\\beta = 6.10 $, for three sea-quark masses with corresponding pion masses in\nthe range $260-475$ MeV. We compute the point-to-point quark propagators, and\nmeasure the time-correlation functions of the pseudoscalar and vector mesons.\nThe inverse lattice spacing is determined by the Wilson flow, while the strange\nand the charm quark masses by the masses of the vector mesons $ \\phi(1020) $\nand $ J/\\psi(3097) $ respectively. Using heavy meson chiral perturbation theory\n(HMChPT) to extrapolate to the physical pion mass, we obtain $ f_D =\n202.3(2.2)(2.6) $ MeV and $ f_{D_s} = 258.7(1.1)(2.9) $ MeV."
    },
    {
        "anchor": "Probing novel TeV physics through precision calculations of scalar and\n  tensor charges of the nucleon: We present an update on the calculation of matrix elements of iso-vector\nscalar, axial and tensor charges between a neutron and a proton state. These\nmatrix elements are needed to probe novel scalar and tensor interactions in\nneutron beta-decay that can arise in extensions of the Standard Model at the\nTeV scale. Our calculations are being done using valence clover fermions on\ndynamical N_f=2+1+1 HISQ configurations generated by the MILC Collaboration. We\nprovide preliminary estimates of the dependence of these matrix elements on the\nlight quark masses, lattice spacing, and the time separation between the source\nand sink of the nucleons. We also find that the renormalization constants\ncalculated using the RI-sMOM scheme are close to unity for the HYP smeared HISQ\nlattices.",
        "positive": "Calculating the chiral condensate of QCD at infinite coupling using a\n  generalised lattice diagrammatic approach: We develop a lattice diagrammatic technique for calculating the chiral\ncondensate of QCD at infinite coupling inspired by recent work of Tomboulis and\nearlier work from the 80's. The technique involves calculating the contribution\nof gauge link diagrams formed from all possible combinations of a number of\nsub-diagram types. This is achieved by performing a resummation, using a\ntruncated number of sub-diagram types. We show how to calculate the relevant\nsub-diagrams, including a new technique for evaluating group integrals with\narbitrary number of gauge link elements, using Young Projectors. Including up\nto four different diagram types we calculate the chiral condensate as a\nfunction of Nf, and show that two real solutions result, which are non-zero for\nall integer Nf. We analyse these solutions and find signs of convergence of the\nexpansion at small Nf. We discuss sources of error associated with this\napproach in detail and implement a technique to reduce over-counting of\ndiagrams."
    },
    {
        "anchor": "Quark structure from the lattice Operator Product Expansion: We have reported elsewhere in this conference on our continuing project to\ndetermine non-perturbative Wilson coefficients on the lattice, as a step\ntowards a completely non-perturbative determination of the nucleon structure.\nIn this talk we discuss how these Wilson coefficients can be used to extract\nNachtmann moments of structure functions, using the case of off-shell\nLandau-gauge quarks as a first simple example. This work is done using overlap\nfermions, because their improved chiral properties reduce the difficulties due\nto operator mixing.",
        "positive": "Spectral and transport properties from lattice QCD: In these lecture notes we will discuss recent progress in extracting spectral\nand transport properties from lattice QCD. We will focus on results of probes\nof the thermal QCD medium as well as transport coefficients which are important\ningredients for hydrodynamic and transport models that describe the evolution\nof the produced medium. These include electromagnetic probes, like the rates of\nemitted photons and dileptons, quarkonium spectral functions as well as\ntransport coefficients like the electrical conductivity or heavy flavor\ndiffusion coefficients of the quark gluon plasma (QGP). All these real time\nquantities are encoded in the vector meson spectral function. A direct\ndetermination of the spectral functions is not possible in Euclidean lattice\nQCD calculations but they can be analytically continued from imaginary to real\ntime. Therefore it is possible to relate the spectral function to the\ncorresponding Euclidean correlation functions. In the following sections we\nwill discuss the procedure to determine the required correlation functions and\nthe extraction of the spectral functions from lattice QCD correlators. We will\nillustrate the concepts and methods to obtain spectral functions and related\nphysical observables from continuum extrapolated correlation functions. We will\nfocus here on results obtained from continuum extrapolated lattice correlation\nfunctions, which requires large and fine lattices, which so far was only\npossible in quenched approximation. We will only give a brief introduction to\nlattice QCD and refer to the textbooks [1,2,3,4] and lecture notes [5] for more\ndetailed introductions to lattice field theory. For the topics addressed in\nthis lecture note we also like to refer to the overview articles on QCD\nthermodynamics and the QCD phase transition [5,6,7] and quarkonium in extreme\nconditions [8]."
    },
    {
        "anchor": "QCD in the heavy dense regime: Large $N_c$ and quarkyonic matter: After combined character and hopping expansions and integration over the\nspatial gauge links, lattice QCD reduces to a three-dimensional $SU(3)$\nPolyakov loop model with complicated interactions. A simple truncation of the\neffective theory is valid for heavy quarks on reasonably fine lattices and can\nbe solved by linked cluster expansion in its effective couplings. This was used\nealier to demonstrate the onset transition to baryon matter in the cold and\ndense regime. Repeating these studies for general $N_c$, one finds that for\nlarge $N_c$ the onset transition becomes first-order, and the pressure scales\nas $p\\sim N_c$ through three consecutive orders in the hoppoing expansion.\nThese features are consistent with the formal definition of quarkyonic matter\ngiven in the literature. We discuss the implications for $N_c=3$ and physical\nQCD.",
        "positive": "Formulation of chiral gauge theories: We present a formulation of chiral gauge theories, which admits more general\nspectra of Dirac operators and reveals considerably more possibilities for the\nstructure of the chiral projections. Our two forms of correlation functions\nboth also apply in the presence of zero modes and for any value of the index.\nThe decomposition of the total set of pairs of bases into equivalence classes\nis carefully analyzed. Transformation properties are derived."
    },
    {
        "anchor": "Gravitational form factors of the proton from lattice QCD: The gravitational form factors (GFFs) of a hadron encode fundamental aspects\nof its structure, including its shape and size as defined from e.g., its energy\ndensity. This work presents a determination of the flavor decomposition of the\nGFFs of the proton from lattice QCD, in the kinematic region $0\\leq -t\\leq\n2~\\text{GeV}^2$. The decomposition into up-, down-, strange-quark, and gluon\ncontributions provides first-principles constraints on the role of each\nconstituent in generating key proton structure observables, such as its\nmechanical radius, mass radius, and $D$-term.",
        "positive": "Lattice Monte Carlo methods for systems far from equilibrium: We present a new numerical Monte Carlo approach to determine the scaling\nbehavior of lattice field theories far from equilibrium. The presented methods\nare generally applicable to systems where classical-statistical fluctuations\ndominate the dynamics. As an example, these methods are applied to the\nrandom-force-driven one-dimensional Burgers' equation - a model for\nhydrodynamic turbulence. For a self-similar forcing acting on all scales the\nsystem is driven to a nonequilibrium steady state characterized by a Kolmogorov\nenergy spectrum. We extract correlation functions of single- and multi-point\nquantities and determine their scaling spectrum displaying anomalous scaling\nfor high-order moments. Varying the external forcing we are able to tune the\nsystem continuously from equilibrium, where the fluctuations are short-range\ncorrelated, to the case where the system is strongly driven in the infrared. In\nthe latter case the nonequilibrium scaling of small-scale fluctuations are\nshown to be universal."
    },
    {
        "anchor": "The critical line of QCD with four degenerate quarks: We determine the pseudo-critical couplings at imaginary chemical potentials\nby high-statistics Monte Carlo simulations of QCD with four degenerate quarks\nat non-zero temperature and baryon density by the method of analytic\ncontinuationan. We reveal deviations from the simple quadratic dependence on\nthe chemical potential visible in earlier works on the same subject. Finally,\nwe discuss the implications of our findings for the shape of the\npseudo-critical line at real chemical potential, comparing different possible\nextrapolations.",
        "positive": "Exploring the worldline formulation of the Potts model: We revisit the issue of worldline formulations for the q-state Potts model\nand discuss a worldline representation in arbitrary dimensions which also\nallows for magnetic terms. For vanishing magnetic field we implement a Hodge\ndecomposition for resolving the constraints with dual variables, which in two\ndimensions implies self-duality as a simple corollary. We present exploratory\n2-d Monte Carlo simulations in terms of the worldlines, based on worm\nalgorithms. We study both, vanishing and non-zero magnetic field, and explore q\nbetween q = 2 and q = 30, i.e., Potts models with continuous, as well as strong\nfirst order transitions."
    },
    {
        "anchor": "Three-quark ground-state potential in the SU(3) lattice QCD: With the smearing technique, the three-quark (3Q) ground-state potential\n$V_{\\rm 3Q}$ is numerically extracted in the SU(3)$_c$ lattice QCD Monte Carlo\nsimulation with $12^3 \\times 24$ and $\\beta=5.7$ at the quenched level. With\naccuracy better than a few %, $V_{\\rm 3Q}$ is well described by a sum of a\nconstant $C_{\\rm 3Q}$, the two-body Coulomb part $-A_{\\rm 3Q}\\sum_{i<j}\n\\frac1{|{\\bf r}_i-{\\bf r}_j|}$ and the three-body linear confinement part\n$\\sigma_{\\rm 3Q} L_{\\rm min}$, where $L_{\\rm min}$ denotes the minimal length\nof the color flux tube linking the three quarks. By comparing with the Q-$\\bar\n{\\rm Q}$ potential, we find a universal feature of the string tension as\n$\\sigma_{\\rm 3Q} \\simeq \\sigma_{\\rm Q \\bar Q}$ and the one-gluon-exchange\nresult for the Coulomb coefficient as $A_{\\rm 3Q} \\simeq \\frac12 A_{\\rm Q \\bar\nQ}$. All our results including the constant term are consistent with the\nrequirement on the diquark limit in the lattice regularization.",
        "positive": "Bound states on the lattice with partially twisted boundary conditions: We propose a method to study the nature of exotic hadrons by determining the\nwave function renormalization constant $Z$ from lattice simulations. It is\nshown that, instead of studying the volume-dependence of the spectrum, one may\ninvestigate the dependence of the spectrum on the twisting angle, imposing\ntwisted boundary conditions on the fermion fields on the lattice. In certain\ncases, e.g., the case of the $DK$ bound state which is addressed in detail, it\nis demonstrated that the partial twisting is equivalent to the full twisting up\nto exponentially small corrections."
    },
    {
        "anchor": "Parton Distribution Amplitudes and Non-Perturbative Renormalisation: We present results for the first two moments of the light-cone distribution\namplitudes of the pion and kaon pseudo-scalar mesons and of the rho, K* and phi\nvector mesons. The calculations are performed on the RBC/UKQCD collaborations'\nensembles generated with the Iwasaki gauge action and with 2+1 flavours of\ndomain wall fermions. In addition we also provide some results on the necessary\nnon-perturbative renormalisation which we perform using the Rome-Southampton\nmethod. We discuss the benefits of the momentum source approach such as much\nsmaller statistical errors and the possibility to see effects of the\ndiscretisation.",
        "positive": "Fisher's zeros of quasi-Gaussian densities of states: We discuss apparent paradoxes regarding the location of the zeros of the\npartition function in the complex $\\beta$ plane (Fisher's zeros) of a pure\nSU(2) lattice gauge theory in 4 dimensions. We propose a new criterion to draw\nthe region of the complex $\\beta$ plane where reweighting methods can be\ntrusted when the density of states is almost but not exactly Gaussian. We\npropose new methods to infer the existence of zeros outside of this region. We\ndemonstrate the reliability of these proposals with quasi Gaussian Monte Carlo\ndistributions where the locations of the zeros can be calculated by independent\nnumerical methods. The results are presented in such way that the methods can\nbe applied for general lattice models. Applications to specific lattice models\nwill be discussed in a separate publication."
    },
    {
        "anchor": "Functional Fit Approach (FFA) for Density of States method: SU(3) spin\n  system and SU(3) lattice gauge theory with static color sources: We apply a recently developed variant of the Density of States (DoS) method,\nthe so-called Functional Fit Approach (FFA) to two different models: the SU(3)\nspin model and SU(3) lattice gauge theory with static color sources. Both\nmodels can be derived from QCD and inherit the complex action problem at finite\ndensity. We discuss the implementation of DoS FFA in the two models and compute\nobservables related to the particle density. For the SU(3) spin model we show\nthat the results are in good agreement with the results from a Monte Carlo\nsimulation in the dual formulation, which is free of the complex action\nproblem. For the case of SU(3) lattice gauge theory with static color sources\nwe present first results for the particle number as a function of the coupling\nfor different values of the chemical potential.",
        "positive": "Spectral study of a chiral limit without chiral condensate: Random Matrix Theory (RMT) has elaborated successful predictions for Dirac\nspectra in field theoretical models. However, a generic assumption by RMT has\nbeen a non-vanishing chiral condensate $\\Sigma$ in the chiral limit. Here we\nconsider the 2-flavour Schwinger model, where this assumption does not hold. We\nsimulated this model with dynamical overlap hypercube fermions, and entered\nterra incognita by analysing this Dirac spectrum. The usual RMT prediction for\nthe unfolded level spacing distribution in a unitary ensemble is precisely\nconfirmed. The microscopic spectrum does not perform a Banks-Casher plateau.\nInstead the obvious expectation is a density of the lowest eigenvalue\n$\\lambda_{1}$ which increases $\\propto \\lambda_{1}^{1/3}$. That would\ncorrespond to a scale-invariant parameter $\\propto \\lambda V^{3/4}$, which is,\nhowever, incompatible with our data. Instead we observe to high precision a\nscale-invariant parameter $z \\propto \\lambda V^{5/8}$. This surprising result\nimplies a microscopic spectral density $\\propto \\lambda_1^{3/5}$, which still\nremains to be understood in the light of RMT."
    },
    {
        "anchor": "BCS Diquark Condensation in the 3+1d Lattice NJL Model: We present preliminary evidence of BCS diquark condensation in the 3+1\ndimensional Nambu-Jona-Lasinio (NJL) model at non-zero chemical potential (mu)\non the lattice. Large N results are used to match the model's parameters to low\nenergy, zero density phenomenology. A diquark source j is added in a partially\nquenched approximation to enable the measurement of lattice diquark\nobservables. In particular measurements are made of the diquark condensate and\nsusceptibilities as functions of j which support the existence of a BCS phase\nat high mu.",
        "positive": "Lattice QCD and Chiral Lagrangians: After a very brief review of the formalism of lattice gauge theories we show\nhow one can calculate the parameters of the continuum chiral Lagrangians\nproceeding through the derivation of an effective lattice chiral Lagrangian as\nan intermediary step. The derivation is done in the strong coupling limit. We\nalso discuss how the derivation could be carried out in the intermediate\ncoupling domain by numerical simulation techniques. Based on a lecture given by\nC. Rebbi at the 1993 ICTP Summer School in High Energy Physics and Cosmology,\nto be published in the proceedings of the School (World Scientific Publishing -\nSingapore - 1994.)"
    },
    {
        "anchor": "Ghost-gluon coupling, power corrections and $\u039b_{\\bar{MS}}$ from\n  twisted-mass lattice QCD at $N_f=2$: A non-perturbative calculation of the ghost-gluon running QCD coupling\nconstant is performed using $N_f=2$ twisted-mass dynamical fermions. The\nextraction of $\\Lambda_{\\bar{MS}}$ in the chiral limit reveals the presence of\na non-perturbative OPE contribution that is assumed to be dominated by a\ndimension-two $\\VEV{A^2}$ condensate. In this contest a novel method for\ncalibrating the lattice spacing in lattice simulations is presented.",
        "positive": "CP breaking in lattice chiral gauge theory: The CP symmetry is not manifestly implemented for the local and doubler-free\nGinsparg-Wilson operator in lattice chiral gauge theory. We precisely identify\nwhere the effects of this CP breaking appear."
    },
    {
        "anchor": "Evading the model sign problem in the PNJL model with repulsive\n  vector-type interaction via path optimization: We discuss the sign problem in the Polyakov loop extended Nambu--Jona-Lasinio\nmodel with repulsive vector-type interaction by using the path optimization\nmethod. In this model, both of the Polyakov loop and the vector-type\ninteraction cause the model sign problem, and several prescriptions have been\nutilized even in the mean field treatment. In the path optimization method,\nintegration variables are complexified and the integration path (manifold) is\noptimized to evade the sign problem, or equivalently to enhance the average\nphase factor. Within the homogeneous field ansatz, the path is optimized by\nusing the feedforward neural network. We find that the assumptions adopted in\nprevious works, $\\mathrm{Re}\\,A_8 \\simeq 0$ and $\\mathrm{Re}\\,\\omega \\simeq 0$,\ncan be justified from the Monte-Carlo configurations sampled on the optimized\npath. We also derive the Euler-Lagrange equation for the optimal path to\nsatisfy. The two optimized paths, the solution of the Euler-Lagrange equation\nand the variationally optimized path, agree with each other in the region with\nlarge statistical weight.",
        "positive": "Coulomb and Landau Gauge Fixing in GPUs using CUDA and MILC: In this work, we present the GPU implementation of the overrelaxation and\nsteepest descent method with Fourier acceleration methods for Laudau and\nCoulomb gauge fixing using CUDA for SU(N) with N>2. A multi-GPU implementation\nof the overrelaxation method is also presented using MPI and CUDA. The GPU\nperformance was measured on BlueWaters and compared against the gauge fixing of\nthe CPU MILC code."
    },
    {
        "anchor": "Volume dependences from lattice chiral perturbation theory: The physics of pions within a finite volume is explored using lattice\nregularized chiral perturbation theory. This regularization scheme permits a\nstraightforward computational approach to be used in place of analytical\ncontinuum techniques. Using the pion mass, decay constant, form factor and\ncharge radius as examples, it is shown how numerical results for volume\ndependences are obtained at the one-loop level from simple summations.",
        "positive": "Interaction of confining vortices in SU(2) lattice gauge theory: Center projection of SU(2) lattice gauge theory allows to isolate magnetic\nvortices as confining configurations. The vortex density scales according to\nthe renormalization group, implying that the vortices are physical objects\nrather than lattice artifacts. Here, the binary correlations between points at\nwhich vortices pierce a given plane are investigated. We find an attractive\ninteraction between the vortices. The correlations show the correct scaling\nbehavior and are therefore physical. The range of the interaction is found to\nbe (0.4 +/- 0.2) fm, which should be compared with the average planar vortex\ndensity of approximately 2 vortices/fm^2. We comment on the implications of\nthese results for recent discussions of the Casimir scaling behavior of higher\ndimensional representation Wilson loops in the vortex confinement picture."
    },
    {
        "anchor": "Tensor form factor of $D \\to \u03c0(K) \\ell \u03bd$ and $D \\to \u03c0(K) \\ell\n  \\ell$ decays with $N_f=2+1+1$ twisted-mass fermions: We present the first lattice Nf=2+1+1 determination of the tensor form factor\n$f_T^{D \\pi(K)}(q^2)$ corresponding to the semileptonic and rare $D \\to \\pi(K)$\ndecays as a function of the squared 4-momentum transfer $q^2$. Together with\nour recent determination of the vector and scalar form factors we complete the\nset of hadronic matrix elements regulating the semileptonic and rare $D \\to\n\\pi(K)$ transitions within and beyond the Standard Model, when a non-zero\ntensor coupling is possible. Our analysis is based on the gauge configurations\nproduced by ETMC with Nf=2+1+1 flavors of dynamical quarks, which include in\nthe sea, besides two light mass-degenerate quarks, also the strange and charm\nquarks with masses close to their physical values. We simulated at three\ndifferent values of the lattice spacing and with pion masses as small as 220\nMeV. The matrix elements of the tensor current are determined for plenty of\nkinematical conditions in which parent and child mesons are either moving or at\nrest. As in the case of the vector and scalar form factors, Lorentz symmetry\nbreaking due to hypercubic effects is clearly observed also in the data for the\ntensor form factor and included in the decomposition of the current matrix\nelements in terms of additional form factors. After the extrapolations to the\nphysical pion mass and to the continuum and infinite volume limits we determine\nthe tensor form factor in the whole kinematical region accessible in the\nexperiments. A set of synthetic data points, representing our results for\n$f_T^{D \\pi(K)}(q^2)$ for several selected values of $q^2$, is provided and the\ncorresponding covariance matrix is also available. At zero four-momentum\ntransfer we get $f_T^{D \\pi}(0) = 0.506 (79)$ and $f_T^{D K}(0) = 0.687 (54)$,\nwhich correspond to $f_T^{D \\pi}(0)/f_+^{D \\pi}(0) = 0.827 (114)$ and $f_T^{D\nK}(0)/f_+^{D K}(0)= 0.898 (50)$.",
        "positive": "Scalar and tensor charmonium resonances in coupled-channel scattering\n  from QCD: We determine $J^{PC}=0^{++}$ and $2^{++}$ hadron-hadron scattering amplitudes\nin the charmonium energy region up to 4100 MeV using lattice QCD, a\nfirst-principles approach to QCD. Working at $m_\\pi\\approx 391$ MeV, more than\n200 finite-volume energy levels are computed and these are used in extensions\nof the L\\\"uscher formalism to determine infinite-volume coupled-channel\nscattering amplitudes. We find that this energy region contains a single\n$\\chi_{c0}$ and a single $\\chi_{c2}$ resonance. Both are found as pole\nsingularities on the closest unphysical Riemann sheet, just below 4000 MeV with\nwidths around 70 MeV. The largest couplings are to kinematically-closed $D^*\n\\bar{D}^*$ channels in $S$-wave, and couplings to several decay channels\nconsisting of pairs of open-charm mesons are found to be large and significant\nin both cases. Above the ground state $\\chi_{c0}$, no other scalar bound-states\nor near-$D\\bar{D}$ threshold resonances are found, in contrast to several\ntheoretical and experimental studies."
    },
    {
        "anchor": "FLAG Review 2021: We review lattice results related to pion, kaon, $D$-meson, $B$-meson, and\nnucleon physics with the aim of making them easily accessible to the nuclear\nand particle physics communities. More specifically, we report on the\ndetermination of the light-quark masses, the form factor $f_+(0)$ arising in\nthe semileptonic $K \\to \\pi$ transition at zero momentum transfer, as well as\nthe decay constant ratio $f_K/f_\\pi$ and its consequences for the CKM matrix\nelements $V_{us}$ and $V_{ud}$. Furthermore, we describe the results obtained\non the lattice for some of the low-energy constants of $SU(2)_L\\times SU(2)_R$\nand $SU(3)_L\\times SU(3)_R$ Chiral Perturbation Theory. We review the\ndetermination of the $B_K$ parameter of neutral kaon mixing as well as the\nadditional four $B$ parameters that arise in theories of physics beyond the\nStandard Model. For the heavy-quark sector, we provide results for $m_c$ and\n$m_b$ as well as those for the decay constants, form factors, and mixing\nparameters of charmed and bottom mesons and baryons. These are the heavy-quark\nquantities most relevant for the determination of CKM matrix elements and the\nglobal CKM unitarity-triangle fit. We review the status of lattice\ndeterminations of the strong coupling constant $\\alpha_s$. We consider nucleon\nmatrix elements, and review the determinations of the axial, scalar and tensor\nbilinears, both isovector and flavor diagonal. Finally, in this review we have\nadded a new section reviewing determinations of scale-setting quantities.",
        "positive": "$K \u03c0$ scattering and the $K^*(892)$ resonance in 2+1 flavor QCD: In this project, we will compute the form factors relevant for $B \\to K^*(\\to\nK \\pi)\\ell^+\\ell^-$ decays. To map the finite-volume matrix elements computed\non the lattice to the infinite-volume $B \\to K \\pi$ matrix elements, the $K\n\\pi$ scattering amplitude needs to be determined using L\\\"uscher's method. Here\nwe present preliminary results from our calculations with $2+1$ flavors of\ndynamical clover fermions. We extract the $P$-wave scattering phase shifts and\ndetermine the $K^*$ resonance mass and the $K^* K \\pi$ coupling for two\ndifferent ensembles with pion masses of $317(2)$ and $178(2)$ MeV."
    },
    {
        "anchor": "Weyl fermions on a finite lattice: The phenomenon of unpaired Weyl fermions appearing on the sole 2n-dimensional\nboundary of a (2n+1)-dimensional manifold with massive Dirac fermions was\nrecently analyzed in a companion paper by one of the authors. In this Letter we\nshow that similar unpaired Weyl edge states can be seen on a finite lattice. In\nparticular, we consider the discretized Hamiltonian for a Wilson fermion in\n(2+1) dimensions with a 1+1 dimensional boundary and continuous time. We\ndemonstrate that the low lying boundary spectrum is indeed Weyl-like: it has a\nlinear dispersion relation and definite chirality and circulates in only one\ndirection around the boundary. We comment on how our results are consistent\nwith Nielsen-Ninomiya theorem. This work removes one potential obstacle facing\nthe program for regulating chiral gauge theories recently proposed by one of\nthe authors.",
        "positive": "Mean field theory of effective spin models as a baryon fugacity\n  expansion: The free energy of effective spin or \"Polyakov line\" models with a chemical\npotential, based on the U(N) group, does not depend on the chemical potential.\nIn a mean field-inspired expansion, we show how the condition of unit\ndeterminant, taking U(N) to SU(N), reintroduces the chemical potential, and\nallows us to express the free energy, as a function of mean field variational\nparameters, in terms of an expansion in the baryon (rather than the quark)\nfugacity at each lattice site. We solve the SU(3) mean field equations\nnumerically to determine the phase diagram and compute observables. We also\ncalculate the first corrections to the leading order mean field results, and\nfind that these can significantly shift the endpoint of a line of first order\ntransitions. The problem of deriving an effective spin model from full QCD is\ndiscussed."
    },
    {
        "anchor": "Lattice Flavourdynamics: I present a selection of recent lattice results in flavourdynamics, including\nthe status of the calculation of quark masses and a variety of weak matrix\nelements relevant for the determination of CKM matrix elements. Recent\nimprovements in the momentum resolution of lattice computations and progress\ntowards precise computations of $K\\to\\pi\\pi$ decay amplitudes are also\nreviewed.",
        "positive": "Spectroscopy with Local Multi-hadron Interpolators in Lattice QCD: The positive-parity nucleon spectrum is studied in 2 + 1 flavour lattice QCD\nin an attempt to discover novel low-lying energy eigenstates in the region of\nthe Roper resonance. In this work, we employ standard three-quark interpolating\nfields and introduce new local five-quark meson-baryon operators that hold the\npossibility of revealing new states that have been missed in previous studies.\nMotivated by phenomenological arguments, five-quark interpolators based on the\n$\\sigma{N}$, $\\pi{N}$ and $a_0{N}$ channels are constructed. Despite the\nintroduction of qualitatively different operators, no novel energy levels are\nextracted near the regime of the Roper resonance."
    },
    {
        "anchor": "Lattice QCD study of static quark and antiquark correlations at finite\n  $T$ via entanglement entropies: With the aim of clarification of color correlations among quarks, we\ninvestigate the color correlation between a static quark and an antiquark\n(static $q\\bar q$) below and above the phase transition temperature $T_c$\nthrough the entanglement entropy(EE). By a quenched lattice QCD calculation on\nan anisotropic lattice adopting the standard Wilson gauge action in the Coulomb\ngauge, we compute a reduced density matrix $\\rho$ defined in the color space,\nand the entanglement entropy $S_{\\rm EE}$ constructed from $\\rho$. The spatial\nvolume is $L^3 = 24^3$ and the temporal extents are $N_T =\n12,13,14,15,16,18,20$ and $24$, with a gauge coupling $\\beta = 5.75$ and a\nrenormalized anisotropy $\\xi = 4.0$, which corresponds to temperatures between\n180 and 370 MeV. From an analysis of $\\rho$ and $S_{\\rm EE}$, the color\ncorrelation between $q\\bar q$ pairs is obtained as a function of the interquark\ndistance $R$ and the temperature $T$. Below $T_c$, the $R$-dependence of the\ncolor correlation resembles that at $T=0$: the quark's color correlation\ngradually decreases as $R$ increases due to the color screening by in-between\ngluons. Above $T_c$, due to the deconfinement phase transition, the color\ncorrelation among quarks is found to quickly dissappear. Further, we\ninvestigate the color screening effect via the screening mass defined by\n$\\rho$, and discuss the differences in the screening properties between the\nsmall and large R regions.",
        "positive": "B-meson spectroscopy in HQET at order 1/m: We present a study of the B spectrum performed in the framework of Heavy\nQuark Effective Theory expanded to next-to-leading order in 1/m and\nnon-perturbative in the strong coupling. Our analyses have been performed on\nNf=2 lattice gauge field ensembles corresponding to three different lattice\nspacings and a wide range of pion masses. We obtain the Bs-meson mass and\nhyperfine splittings of the B- and Bs-mesons that are in good agreement with\nthe experimental values and examine the mass difference m_{Bs}-m_B as a further\ncross-check of our previous estimate of the b-quark mass. We also report on the\nmass splitting between the first excited state and the ground state in the B\nand Bs systems."
    },
    {
        "anchor": "Chiral perturbation theory, finite size effects and the\n  three-dimensional $XY$ model: We study finite size effects of the d=3 $XY$ model in terms of the chiral\nperturbation theory. We calculate by Monte Carlo simulations physical\nquantities which are, to order of $(1/L)^2$, uniquely determined only by two\nlow energy constants. They are the magnetization and the helicity modulus (or\nthe Goldstone boson decay constant) in infinite volume. We also pay a special\nattention to the region of the validity of the two possible expansions in the\ntheory.",
        "positive": "Non-Abelian dual Meissner effect in SU(3) Yang-Mills theory and\n  confinement/deconfinement phase transition at finite temperature: The dual superconductivity is a promising mechanism for quark confinement. We\nhave proposed the non-Abelian dual superconductivity picture for SU(3)\nYang-Mills theory, and showed the restricted field dominance (called\nconventionally Abelian dominance), and non-Abelian magnetic monopole dominance\nin the string tension. We have further demonstrated by measuring the\nchromoelectric flux that the non-Abelian dual Meissner effect exists and\ndetermined that the dual superconductivity for SU(3) case is of type I, which\nis in sharp contrast to the SU(2) case: the border of type I and type II.\n  In this talk, we focus on the confinement/deconfinement phase transition and\nthe non-Abelian dual superconductivity at a finite temperature: We measure the\nPolyakov loop average and correlator and investigate the restricted field\ndominance in the Polyakov loop. Then, we measure the chromoelectric flux\nbetween a pair of static quark and antiquark created by a pair of Polyakov\nloops, and investigate the non-Abelian dual Meissner effect and its relevance\nto the phase transition."
    },
    {
        "anchor": "Modelling the Quark Determinant in Full QCD Simulations: The computational requirements and dynamics of Monte Carlo simulations of\nunquenched QCD incorporating the infrared quark eigenmodes (up to $\\approx\n\\Lambda_{QCD}$) exactly and UV modes via a loop representation are discussed.\nThe accuracy of such a loop representation is studied for a variety of lattice\nvolumes and quark masses. The method has been successfully applied for lattices\nup to 10$^3$x20 at $a \\simeq$0.17F with improved (clover) action, and allows\nsimulations at or near kappa critical.",
        "positive": "Lattice sine-Gordon model: We obtain nonperturbative results on the sine-Gordon model using the lattice\nfield technique. In particular, we employ the Fourier accelerated hybrid Monte\nCarlo algorithm for our studies. We find the critical temperature of the theory\nbased on autocorrelation time, as well as the finite size scaling of the\n\"thickness\" observable used in an earlier lattice study by Hasenbusch et al. We\nstudy the entropy, which is smooth across all temperatures, supportive of an\ninfinite order transition. This system has a well-known duality with the\nmassive Thirring model, which can play the role of a toy models for\nMontonen-Olive duality in N=4 super-Yang-Mills theory, since it relates\nsolitons to elementary field excitations. Our research lays a groundwork for\nsuch study on the lattice."
    },
    {
        "anchor": "Analytic continuation of the critical line: suggestions for QCD: We perform a numerical study of the systematic effects involved in the\ndetermination of the critical line at real baryonic chemical potential by\nanalytic continuation from results obtained at imaginary chemical potentials.\nWe present results obtained in theories free of the sign problem, such as\ntwo-color QCD with finite baryonic density and three-color QCD with finite\nisospin chemical potential, and comment on general features which could be\nrelevant also to the continuation of the critical line in real QCD at finite\nbaryonic density.",
        "positive": "Susceptibilities and screening masses in two flavor QCD: We studied QCD with two flavors of dynamical staggered quarks at finite\ntemperature, with a bare sea quark mass of about 17 MeV. We report\ninvestigations of baryon, isospin, charge and strangeness susceptibilities, as\nwell as screening masses obtained from correlators of local and one-link\nseparated meson operators. These were studied as functions of valence quark\nmass at several temperatures. Our results for susceptibilities deviate\nsignificantly from ideal gas values, and even more from the weak coupling\nseries. We also report the first measurement of off-diagonal quark number\nsusceptibilities below the transition temperature, Tc, where they are the main\ncontribution to charge fluctuations. We present evidence for a close connection\nbetween the susceptibilities and the screening masses."
    },
    {
        "anchor": "The equation of state of QCD at finite chemical potential: We obtain the baryon number density, n, and the excess contribution to the\npressure, Delta P, at finite chemical potential, mu_B, and temperature, T, by\nresumming the Taylor series expansion in a lattice computation with lattice\nspacing of 1/(4T) and two flavours of quarks at three different quark masses.\nThe method proceeds by giving a critical mu_B and limits on the critical\nexponent, and permits reliable estimations of the errors in resummed\nquantities. We find that n and Delta P are insensitive to the quark mass. We\nalso report the bulk isothermal compressibility, kappa, over a range of T and\nmu_B.",
        "positive": "Chiral transition and deconfinement in N_f = 2 QCD: The transition is studied by means of a disorder parameter detecting\ncondensation of magnetic monopoles in the vacuum. The deconfining transition is\nfound to coincide with the chiral transition and the susceptibility \\rho,\nrelated to the disorder parameter, is consistent with a first order phase\ntransition."
    },
    {
        "anchor": "Dirac-mode expansion for confinement and chiral symmetry breaking: We develop a manifestly gauge-covariant expansion and projection using the\neigen-mode of the QCD Dirac operator. Applying this method to the Wilson loop\nand the Polyakov loop, we perform a direct analysis of the correlation between\nconfinement and chiral symmetry breaking in SU(3) lattice QCD calculation on\n6^4 at beta=5.6 at the quenched level. Notably, the Wilson loop is found to\nobey the area law, and the slope parameter corresponding to the string tension\nor the confinement force is almost unchanged, even after removing the low-lying\nDirac modes, which are responsible to chiral symmetry breaking. We find also\nthat the Polyakov loop remains to be almost zero even without the low-lying\nDirac modes, which indicates the Z_3-unbroken confinement phase. These results\nindicate that one-to-one correspondence does not hold between confinement and\nchiral symmetry breaking in QCD.",
        "positive": "Momentum dependence of the N to Delta transition form factors: We present a new method to determine the momentum dependence of the N to\nDelta transition form factors and demonstrate its effectiveness in the quenched\ntheory at $\\beta=6.0$ on a $32^3 \\times 64$ lattice. We address a number of\ntechnical issues such as the optimal combination of matrix elements and the\nsimultaneous overconstrained analysis of all lattice vector momenta\ncontributing to a given momentum transfer squared, $Q^2$."
    },
    {
        "anchor": "Charmed Baryon Spectroscopy from Lattice QCD with $N_f=2+1+1$ flavors: We present preliminary results of the calculation of the positive-parity\nground state charm baryon spectrum using of N_f=2+1+1$ dynamical quarks. The\ncalculation uses a relativistic heavy-quark action for the valence charm quark,\nclover-Wilson fermions for the valence light quarks and HISQ sea quarks. The\nspectrum is calculated with a lightest pion mass around 220 MeV and two lattice\nspacings ($a\\sim0.12$ fm and 0.09 fm) are used to extrapolate to continuum\nlimit. Our preliminary results are consistent with the currently measured\nbaryon spectrum, except for the isospin-averaged $J=1/2$ $\\Xi_{cc}$ which is\napproximately $2 \\sigma$ above the SELEX observed value. We predict the\nyet-to-be-discovered double and triple-charm baryons $\\Xi_{cc}^*$,\n$\\Omega_{cc}$, $\\Omega_{cc}^*$, $\\Omega_{ccc}$ to have masses 3665(42)(29) MeV,\n3694(40)(45) MeV, 3739(35)(21) MeV and 4782(24)(28) MeV, respectively.",
        "positive": "The Phase Diagram and Spectrum of Gauge-Fixed Abelian Lattice Gauge\n  Theory: We consider a lattice discretization of a covariantly gauge-fixed abelian\ngauge theory. The gauge fixing is part of the action defining the theory, and\nwe study the phase diagram in detail. As there is no BRST symmetry on the\nlattice, counterterms are needed, and we construct those explicitly. We show\nthat the proper adjustment of these counterterms drives the theory to a new\ntype of phase transition, at which we recover a continuum theory of (free)\nphotons. We present both numerical and (one-loop) perturbative results, and\nshow that they are in good agreement near this phase transition. Since\nperturbation theory plays an important role, it is important to choose a\ndiscretization of the gauge-fixing action such that lattice perturbation theory\nis valid. Indeed, we find numerical evidence that lattice actions not\nsatisfying this requirement do not lead to the desired continuum limit. While\nwe do not consider fermions here, we argue that our results, in combination\nwith previous work, provide very strong evidence that this new phase transition\ncan be used to define abelian lattice chiral gauge theories."
    },
    {
        "anchor": "Improved actions for the two-dimensional sigma-model: For the O(N) sigma-model we studied the improvement program for actions with\ntwo- and four-spin interactions. An interesting example is an action which is\nreflection-positive, on-shell improved, and has all the coupling defined on an\nelementary plaquette. We show the large N solution and preliminary Monte Carlo\nresults for N=3.",
        "positive": "New actions for minimally doubled fermions and their counterterms: Minimally doubled fermions provide a cheap and convenient way of simulating\nquarks which preserve chiral symmetry. It has been established that two actions\nof this kind (known as Borici-Creutz and Karsten-Wilczek) require the tuning of\nthree counterterms in order to be properly renormalized. Here we construct some\nmore general minimally doubled actions and investigate the properties of their\ncounterterms."
    },
    {
        "anchor": "Effective field theories for QCD with rooted staggered fermions: Even highly improved variants of lattice QCD with staggered fermions show\nsignificant violations of taste symmetry at currently accessible lattice\nspacings. In addition, the \"rooting trick\" is used in order to simulate with\nthe correct number of light sea quarks, and this makes the lattice theory\nnonlocal, even though there is good reason to believe that the continuum limit\nis in the correct universality class. In order to understand scaling\nviolations, it is thus necessary to extend the construction of the Symanzik\neffective theory to include rooted staggered fermions. We show how this can be\ndone, starting from a generalization of the renormalization-group approach to\nrooted staggered fermions recently developed by one of us. We then explain how\nthe chiral effective theory follows from the Symanzik action, and show that it\nleads to \"rooted\" staggered chiral perturbation theory as the correct chiral\ntheory for QCD with rooted staggered fermions. We thus establish a direct link\nbetween the renormalization-group based arguments for the correctness of the\ncontinuum limit and the success of rooted staggered chiral perturbation theory\nin fitting numerical results obtained with the rooting trick. In order to\ndevelop our argument, we need to assume the existence of a standard\npartially-quenched chiral effective theory for any local partially-quenched\ntheory. Other technical, but standard, assumptions are also required.",
        "positive": "$B\\to K^* \u03b3$ decay on APE: We present results for the radiative decay $B\\to K^* \\gamma$, obtained by\nusing the Clover action at $\\beta = 6.0$ on APE. The compatibility between the\nscaling laws predicted by the Heavy Quark Effective Theory (HQET) and pole\ndominance is discussed. The final result depends crucially on the assumed\n$q^2$-dependence of the form factors."
    },
    {
        "anchor": "Scaling tests of the improved Kogut-Susskind quark action: Improved lattice actions for Kogut-Susskind quarks have been shown to improve\nrotational symmetry and flavor symmetry. In this work we find improved scaling\nbehavior of the rho and nucleon masses expressed in units of a length scale\nobtained from the static quark potential, and better behavior of the Dirac\noperator in instanton backgrounds.",
        "positive": "Percolation of Vortices in the 3D Abelian Lattice Higgs Model: The compact Abelian Higgs model is simulated on a cubic lattice where it\npossesses vortex lines and pointlike magnetic monopoles as topological defects.\nThe focus of this high-precision Monte Carlo study is on the vortex network,\nwhich is investigated by means of percolation observables. In the region of the\nphase diagram where the Higgs and confinement phases are separated by a\nfirst-order transition, it is shown that the vortices percolate right at the\nphase boundary, and that the first-order nature of the transition is reflected\nby the network. In the crossover region, where the phase boundary ceases to be\nfirst order, the vortices are shown to still percolate. In contrast to other\nobservables, the percolation observables show finite-size scaling. The\nexponents characterizing the critical behavior of the vortices in this region\nare shown to fall in the random percolation universality class."
    },
    {
        "anchor": "Light hadron spectroscopy: I review the progress that has been made in light hadron spectroscopy from\nlattice QCD, since the LATTICE'94 conference in Bielefeld.",
        "positive": "The Analysis of Space-Time Structure in QCD Vacuum II: Dynamics of\n  Polarization and Absolute X-Distribution: We propose a framework for quantitative evaluation of dynamical tendency for\npolarization in arbitrary random variable that can be decomposed into a pair of\northogonal subspaces. The method uses measures based on comparisons of given\ndynamics to its counterpart with statistically independent components. The\nformalism of previously considered X-distributions is used to express the\naforementioned comparisons, in effect putting the former approach on solid\nfooting. Our analysis leads to definition of a suitable correlation coefficient\nwith clear statistical meaning. We apply the method to the dynamics induced by\npure-glue lattice QCD in local left-right components of overlap Dirac\neigenmodes. It is found that, in finite physical volume, there exists a\nnon-zero physical scale in the spectrum of eigenvalues such that eigenmodes at\nsmaller (fixed) eigenvalues exhibit convex X-distribution (positive\ncorrelation), while at larger eigenvalues the distribution is concave (negative\ncorrelation). This chiral polarization scale thus separates a regime where\ndynamics enhances chirality relative to statistical independence from a regime\nwhere it suppresses it, and gives an objective definition to the notion of\n\"low\" and \"high\" Dirac eigenmode. We propose to investigate whether the\npolarization scale remains non-zero in the infinite volume limit, in which case\nit would represent a new kind of low energy scale in QCD."
    },
    {
        "anchor": "On the evaluation of universal non-perturbative constants in O(N) sigma\n  models: We investigate the relation between on-shell and zero-momentum\nnon-perturbative quantities entering the parametrization of the two-point\nGreen's function of two-dimensional non-linear O(N) sigma models. We present\naccurate estimates of ratios of mass-scales and renormalization constants,\nobtained by an analysis of the strong-coupling expansion of the two-point\nGreen's function. These ratios allow to connect exact known on-shell results\nwith typical zero-momentum lattice evaluations. Our results are supported by\nthe 1/N-expansion.",
        "positive": "String breaking mechanisms induced by magnetic and electric condensates: The normal confining phase of gauge theories is characterised by the\ncondensation of magnetic monopoles and center vortices. Sometimes in coupled\ngauge system one finds another phase with simultaneous condensation of electric\nand magnetic charges. In both phases the confining string breaks down at a\ngiven scale because of pair creation, however the mechanism is different. In\nthe former case the string breaking is a mixing phenomenon which is invisible\nin the Wilson loop. On the contrary, in presence of both electric and magnetic\ncondensates the string breaking can be observed even in the Wilson loops.\nNumerical experiments on a 3D $Z_2$ gauge-Higgs system neatly show this new\nphenomenon."
    },
    {
        "anchor": "Handling Excited States on the Lattice: The GEVP Method: High-precision calculations of hadron spectroscopy are a crucial task for\nLattice QCD. State-of-the-art techniques are needed to disentangle the\ncontributions from different energy states, such as solving the generalized\neigenvalue problem (GEVP) for zero-momentum hadron correlators in an efficient\nway. We review the method and discuss its application in the determination of\nthe $B_s$-meson spectrum using (quenched) nonperturbative HQET at order\n$1/m_b$.",
        "positive": "SU(3) hybrid static potentials at small quark-antiquark separations from\n  fine lattices: We summarize our recent lattice gauge theory computation of the $\\Pi_u$ and\n$\\Sigma_u^-$ hybrid static potentials at small quark-antiquark separations. We\nprovide parameterizations of the resulting lattice data points, which can be\nused for investigating masses and properties of heavy hybrid mesons in the\nBorn-Oppenheimer approximation."
    },
    {
        "anchor": "Recent progress on nuclear potentials from lattice QCD: A new method for nuclear potentials is reviewed. The strategy to extract the\npotential from the Nambu-Bethe-Salpeter wave function in lattice QCD is\nexplained and the first result based on the method is presented in quenched\nQCD. The recent progress of the method is summarized.",
        "positive": "Opportunities, Challenges, and Fantasies in Lattice QCD: Some important problems in quantitative QCD will certainly yield to hard work\nand adequate investment of resources, others appear difficult but may be\naccessible, and still others will require essentially new ideas. Here I\nidentify several examples in each class."
    },
    {
        "anchor": "Neutron-antineutron oscillations on the lattice: One possible low energy process due to beyond the Standard Model (BSM)\nphysics is the neutron-antineutron transition, where baryon number changes by\ntwo units. In addition to providing a source of baryon number violation in the\nearly universe, interactions of this kind are natural in grand unified theories\n(GUTs) with Majorana neutrinos that violate lepton number. Bounds on these\noscillations can greatly restrict a variety of GUTs, while a non-zero signal\nwould be a \"smoking gun\" for new physics; however, to make a reliable\nprediction, the six-quark nucleon-antinucleon matrix elements must first be\ncalculated non-perturbatively via lattice QCD. We review the current\nunderstanding of this quantity, describe the lattice formalism, and present\npreliminary results from $32^3\\times256$ clover-Wilson lattices with a pion\nmass of 390 MeV.",
        "positive": "Investigation of the Domain Wall Fermion Approach to Chiral Gauge\n  Theories on the Lattice: We investigate a recent proposal to construct chiral gauge theories on the\nlattice using domain wall fermions. We restrict ourselves to the finite volume\ncase, in which two domain walls are present, with modes of opposite chirality\non each of them. We couple the chiral fermions on only one of the domain walls\nto a gauge field. In order to preserve gauge invariance, we have to add a\nscalar field, which gives rise to additional light mirror fermion and scalar\nmodes. We argue that in an anomaly free model these extra modes would decouple\nif our model possesses a so-called strong coupling symmetric phase. However,\nour numerical results indicate that such a phase most probably does not exist.\n---- Note: 9 Postscript figures are appended as uuencoded compressed tar file."
    },
    {
        "anchor": "Numerical study for the c-dependence of fractal dimension in\n  two-dimensional quantum gravity: We numerically investigate the fractal structure of two-dimensional quantum\ngravity coupled to matter central charge c for $-2 \\leq c \\leq 1$. We\nreformulate Q-state Potts model into the model which can be identified as a\nweighted percolation cluster model and can make continuous change of Q, which\nrelates c, on the dynamically triangulated lattice. The c-dependence of the\ncritical coupling is measured from the percolation probability and\nsusceptibility. The c-dependence of the string susceptibility of the quantum\nsurface is evaluated and has very good agreement with the theoretical\npredictions. The c-dependence of the fractal dimension based on the finite size\nscaling hypothesis is measured and has excellent agreement with one of the\ntheoretical predictions previously proposed except for the region near\n$c\\approx 1$.",
        "positive": "First results with non-perturbative fermion improvement: We present initial results for light hadron masses and nucleon structure\nfunctions using a recent proposal for eliminating all $O(a)$ effects from\nWilson fermion simulations in the quenched approximation. With initially\nlimited statistics, we find a much more linear APE plot and a value of the\naxial coupling $g_A$ nearer to the experimental point than with comparable runs\nusing unimproved Wilson fermions."
    },
    {
        "anchor": "Determination of the QCD coupling from the static energy and the free\n  energy: We present two determinations of the strong coupling \\(\\alpha_s\\). The first\none is from the static energy at three-loop accuracy, and may be considered an\nupdate of earlier determinations by some of us. The new analysis includes new\nlattice data at smaller lattice spacings, and reaches distances as short as\n\\(0.0237\\,{\\rm fm}\\). We present a comprehensive and detailed estimate of the\nerror sources that contribute to the uncertainty of the final result,\n$\\alpha_s(M_Z)=0.11660^{+0.00110}_{-0.00056}$. The second determination is\nbased on lattice data for the singlet free energy at finite temperature up to\ndistances as small as \\(0.0081\\,{\\rm fm}\\), from which we obtain\n$\\alpha_s(M_Z)=0.11638^{+0.0009 5}_{-0.00087}$.",
        "positive": "The QCD equation of state from improved staggered fermions: We calculate the equation of state in 2+1 flavor QCD at finite temperature\nwith physical strange quark mass and almost physical light quark masses using\nlattices with temporal extent $N_{\\tau}=8$. Calculations have been performed\nwith two different improved staggered fermion actions, the asqtad and p4\nactions. Overall, we find good agreement between results obtained with these\ntwo $O(a^2)$ improved staggered fermion discretization schemes. A comparison\nwith earlier calculations on coarser lattices is performed to quantify\nsystematic errors in current studies of the equation of state. We also present\nresults for observables that are sensitive to deconfining and chiral aspects of\nthe QCD transition on $N_\\tau=6$ and 8 lattices. We find that deconfinement and\nchiral symmetry restoration happen in the same narrow temperature interval."
    },
    {
        "anchor": "Removing fermion doublers in chiral gauge theories on the lattice: A method for removing fermion doublers in anomaly free chiral gauge theories\non the lattice is proposed. It is proven that the resulting continuum theory is\ngauge invariant and does not require noninvariant counterterms of fine tuning\nof parameters.",
        "positive": "Zeta-regularized Lattice Field Theory with Lorentzian background metrics: Lattice field theory is a very powerful tool to study Feynman's path integral\nnon-perturbatively. However, it usually requires Euclidean background metrics\nto be well-defined. On the other hand, a recently developed regularization\nscheme based on Fourier integral operator $\\zeta$-functions can treat Feynman's\npath integral non-pertubatively in Lorentzian background metrics. In this\narticle, we formally $\\zeta$-regularize lattice theories with Lorentzian\nbackgrounds and identify conditions for the Fourier integral operator\n$\\zeta$-function regularization to be applicable. Furthermore, we show that the\nclassical limit of the $\\zeta$-regularized theory is independent of the\nregularization. Finally, we consider the harmonic oscillator as an explicit\nexample. We discuss multiple options for the regularization and analytically\nshow that they all reproduce the correct ground state energy on the lattice and\nin the continuum limit. Additionally, we solve the harmonic oscillator on the\nlattice in Minkowski background numerically."
    },
    {
        "anchor": "Simulation of Scalar Field Theories with Complex Actions: We develop a method for the simulation of scalar field theories with complex\nactions which is local, simple to implement and can be used in any number of\nspace-time dimensions. For model systems satisfying the $\\mathcal{PT}$ symmetry\ncondition $L^{*}(\\phi)=L(-\\phi)$, the complex weight problem is reduced to a\nsign problem. The sign problem is eliminated completely for a large subclass of\nthese models; this class includes models within the $i\\phi^{3}$ universality\nclass, and also models with nonzero chemical potential. Simulations of models\nfrom this subclass show a rich set of behaviors. Propagators may exhibit damped\noscillations, indicating a clear violation of spectral positivity. Modulated\nphases occur in some models, exhibiting striping and other pattern-forming\nbehaviors. These field theory models are connected to complex systems where\npattern formation occurs because of competition between interactions at two\ndifferent length scales.",
        "positive": "Density and correlations of topological objects near the transition\n  temperature in lattice gluodynamics: Topological lumps are known to be present in gluonic fields of SU(3)\ngluodynamics. Near the transition temperature they were classified either as\nconstituents of nondissociated (anti)calorons, or as constituents of (anti)dyon\npairs, or as isolated (anti)dyons. In this paper we study the density and\ncorrelation functions of these objects at temperature T/T_c=0.96."
    },
    {
        "anchor": "Lattice N=4 three-dimensional super-Yang-Mills: We describe our recent work on the lattice formulation of N=4\nthree-dimensional super-Yang-Mills. Our formulation was based on the\nDonaldson-Witten twist, but we have also been studying the formulation based on\nthe Blau-Thompson twist by Joseph. We find in the latter case there is a single\ncounterterm necessary to restore supersymmetry in the continuum limit, and that\nthis counterterm can be computed with a two-loop calculation in lattice\nperturbation theory. It is crucial that this three-dimensional model is\nsuper-renormalizable. We also describe some of the motivations for studying\nthree-dimensional theories, including mirror symmetry and holographic\ncosmology.",
        "positive": "GPU Acceleration of Swendson-Wang Dynamics: When simulating a lattice system near its critical temperature, local\nalgorithms for modeling the system's evolution can introduce very large\nautocorrelation times into sampled data. This critical slowing down places\nrestrictions on the analysis that can be completed in a timely manner of the\nbehavior of systems around the critical point. Because it is often desirable to\nstudy such systems around this point, a new algorithm must be introduced.\nTherefore, we turn to cluster algorithms, such as the Swendsen-Wang algorithm\nand the Wolff clustering algorithm. They incorporate global updates which\ngenerate new lattice configurations with little correlation to previous states,\neven near the critical point. We look to accelerate the rate at which these\nalgorithm are capable of running by implementing and benchmarking a parallel\nimplementation of each algorithm designed to run on GPUs under NVIDIA's CUDA\nframework. A 17 and 90 fold increase in the computational rate was respectively\nexperienced when measured against the equivalent algorithm implemented in\nserial code."
    },
    {
        "anchor": "Scattering of dark pions in an Sp(4) gauge theory: In this work we consider strongly interacting dark matter candidates as\ncomposite states of $N_f=2$ fermions charged under a dark $Sp(4)$ gauge group\nin the fundamental representation. We give expressions that allow the\ncalculation of correlation functions of two pseudo-Nambu-Goldstone-bosons with\nlattice field theory and present first results on the scattering phase shift in\nthe isospin-2 channel in the theory from first principles. We give a lower\nlimit on the dark matter particle mass by comparing our results with\nastrophysical constraints on the cross-section.",
        "positive": "Algorithmic aspects of multicanonical simulations: Monte Carlo (MC) simulations of many systems, in particular those with\nconflicting constraints, can be considerably speeded up by using multicanonical\nor related methods. Some of these approaches sample with a-priori unknown\nweight factors. After introducing the concept, I shall focus on two aspects:\n(i) Opinions about the optimal choice of weight factors. (ii) Methods to get\nweight factor estimates, with emphasize on a multicanonical recursion."
    },
    {
        "anchor": "Continuum results for light hadrons from 2+1 flavor DWF ensembles: From simultaneous fits to the data from the 2+1 flavor DWF ensembles\ngenerated by the RBC and UKQCD collaborations at two different lattice\nspacings, we present preliminary continuum results for light hadrons. We focus\non light pseudoscalar decay constants and quark masses. Several approaches to\nthe calculation of the lattice spacing are discussed and the errors associated\nwith the chiral extrapolation are explained. We make use of reweighting in the\ndynamical strange quark mass such that our ensembles have a self-consistently\ndetermined strange quark mass.",
        "positive": "The Origins of Lattice Gauge Theory: An anecdotal account of the author's role in the origins of lattice gauge\ntheory, prepared for delivery on the thirtieth anniversary of the publication\nof \"Confinement of Quarks\" [Phys. Rev. D10 (1974) 2445]."
    },
    {
        "anchor": "Gluon and Ghost Propagators in Landau Gauge on the Lattice: We study the ultraviolet behaviour of the ghost and gluon propagators in\nquenched QCD using lattice simulations. Extrapolation of the lattice data\ntowards the continuum allows to use perturbation theory to extract\n$\\Lambda_{\\text{QCD}}$ - the fundamental parameter of the pure gauge theory.\nThe values obtained from the ghost and gluon propagators are coherent. The\nresult for pure gauge SU(3) at three loops is $\\Lambda_{\\ms}\\approx\n320\\text{MeV}$. However this value does depend strongly upon the order of\nperturbation theory and upon the renormalisation description of the continuum\npropagators. Moreover, this value has been obtained without taking into account\npossible power corrections to the short-distance behaviour of correlation\nfunctions.",
        "positive": "Contents of LAT97 Proceedings: We give here the contents pages for the Proceedings of the Lattice '97\nconference (15th International Symposium on Lattice Field Theory) that took\nplace in July 1997 in Edinburgh, Scotland. The contents are in html form with\nclickable links to the papers that exist on the hep-lat archive. We hope that\nthis will make it easier to access the output of the conference in a systematic\nway. Comments on how useful this is/ how it could be improved should be sent to\nc.davies@physics.gla.ac.uk."
    },
    {
        "anchor": "A Dual Algorithm for Non-abelian Yang-Mills coupled to Dynamical\n  Fermions: We extend the dual algorithm recently described for pure, non-abelian\nYang-Mills on the lattice to the case of lattice fermions coupled to\nYang-Mills, by constructing an ergodic Metropolis algorithm for dynamic\nfermions that is local, exact, and built from gauge-invariant boson-fermion\ncoupled configurations. For concreteness, we present in detail the case of\nthree dimensions, for the group SU(2) and staggered fermions, however the\nalgorithm readily generalizes with regard to group and dimension. The treatment\nof the fermion determinant makes use of a polymer expansion; as with previous\nproposals making use of the polymer expansion in higher than two dimensions,\nthe critical question for practical applications is whether the presence of\nnegative amplitudes can be managed in the continuum limit.",
        "positive": "Deconfinement critical point of heavy quark effective lattice theories: Effective three-dimensional Polyakov loop theories derived from QCD by strong\ncoupling and hopping expansions are valid for heavy quarks and can also be\napplied to finite chemical potential $\\mu$, due to their considerably milder\nsign problem. We apply the Monte-Carlo method to the $N_f=1,2$ effective\ntheories up to $\\mathcal{O}(\\kappa^4)$ in the hopping parameter at $\\mu=0$ to\ndetermine the critical quark mass, at which the first-order deconfinement phase\ntransition terminates. The critical end point obtained from the effective\ntheory to order $\\mathcal{O}(\\kappa^2)$ agrees well with 4-dimensional QCD\nsimulations with a hopping expanded determinant by the WHOT-QCD collaboration.\nWe also compare with full QCD simulations and thus obtain a measure for the\nvalidity of both the strong coupling and the hopping expansion in this regime."
    },
    {
        "anchor": "Heavy quark momentum diffusion coefficient from the lattice: We report progress towards computing the heavy quark momentum diffusion\ncoefficient from the lattice correlator of two chromoelectric fields attached\nto a Polyakov loop in pure SU(3) gauge theory. Using a multilevel algorithm and\ntree-level improvement, we study the behavior of the diffusion coefficient as a\nfunction of temperature in the wide range $1.1 < T/Tc < 10^4$.",
        "positive": "Heavy Quark Potentials and Quarkonia Binding: I review recent progress in studying in-medium modification of inter-quark\nforces at finite temperature in lattice QCD. Some applications to the problem\nof quarkonium binding in potential models is also discussed."
    },
    {
        "anchor": "Calorons and localization of quark eigenvectors in lattice QCD: We analyze the localization properties for eigenvectors of the Dirac operator\nin quenched lattice QCD in the vicinity of the deconfinement phase transition.\nStudying the characteristic differences between the Z_3 sectors above the\ncritical temperature T_c, we find indications for the presence of calorons.",
        "positive": "Vanishing of the anomaly in lattice chiral gauge theory: The anomaly cancellation is a basic property of the Standard Model, crucial\nfor its consistence. We consider a lattice chiral gauge theory of massless\nWilson fermions interacting with a non-compact massive U(1) field coupled with\nleft and right handed fermions in four dimensions. We prove in the infinite\nvolume limit, for weak coupling and inverse lattice step of the order of boson\nmass, that the anomaly vanishes up to subleading corrections and under the same\ncondition as in the continuum. The proof is based on a combination of exact\nRenormalization Group, non perturbative decay bounds of correlations and\nlattice symmetries."
    },
    {
        "anchor": "The three-dimensional, three state Potts model in a negative external\n  field: We investigate the critical behaviour of the three-dimensional, three state\nPotts model in presence of a negative external field h, i.e. disfavouring one\nof the three states. A genuine phase transition is present for all values of\n|h|, corresponding to the spontaneous breaking of a residual Z_2 symmetry. The\ntransition is first/second order respectively for small/large values of |h|,\nwith a tricritical field h_tric separating the two regimes. We provide, using\ndifferent and consistent approaches, a precise determination of h_tric; we also\ncompare with previous studies and discuss the relevance of our investigation to\nanalogous studies of the QCD phase diagram in presence of an imaginary chemical\npotential.",
        "positive": "Perfect Lattice Actions for Quarks and Gluons: We use perturbation theory to construct perfect lattice actions for quarks\nand gluons. The renormalized trajectory for free massive quarks is identified\nby blocking directly from the continuum. We tune a parameter in the\nrenormalization group transformation such that for 1-d configurations the\nperfect action reduces to the nearest neighbor Wilson fermion action. The fixed\npoint action for free gluons is also obtained by blocking from the continuum.\nFor 2-d configurations it reduces to the standard plaquette action. Classically\nperfect quark and gluon fields, quark-gluon composite operators and vector and\naxial vector currents are constructed as well. Also the quark-antiquark\npotential is derived from the classically perfect Polyakov loop. The\nquark-gluon and 3-gluon perfect vertex functions are determined to leading\norder in the gauge coupling. We also construct a new block factor $n$\nrenormalization group transformation for QCD that allows to extend our results\nbeyond perturbation theory. For weak fields it leads to the same perfect action\nas blocking from the continuum. For arbitrarily strong 2-d Abelian gauge fields\nthe Manton plaquette action is classically perfect for this transformation."
    },
    {
        "anchor": "Simulations with Complex Measure: A method is proposed to handle the sign problem in the simulation of systems\nhaving indefinite or complex-valued measures. In general, this new approach,\nwhich is based on renormalisation blocking, is shown to yield statistical\nerrors smaller than the crude Monte Carlo method using absolute values of the\noriginal measures. The improved method is applied to the 2D Ising model with\ntemperature generalised to take on complex values. It is also adapted to\nimplement Monte Carlo Renormalisation Group calculations of the magnetic and\nthermal critical exponents.",
        "positive": "Lattice simulation of $QC_2D$ with $N_f=2$ at non-zero baryon density: The lattice simulations of $QC_2D$ with two flavors of staggered fermions and\nnon-zero quark chemical potential $\\mu_q$ have been performed. Dependencies of\nthe Polyakov loop, chiral condensate and baryon number density on $\\mu_q$ were\nstudied. We found that an increase of the baryon chemical potential leads to\nchiral symmetry restoration. At small values of $\\mu_q$, our results for the\nbaryon number density agree with ChPT predictions."
    },
    {
        "anchor": "Extending the eigCG algorithm to nonsymmetric Lanczos for linear systems\n  with multiple right-hand sides: The technique that was used to build the EigCG algorithm for sparse symmetric\nlinear systems is extended to the nonsymmetric case using the BiCG algorithm.\nWe show that, similarly to the symmetric case, we can build an algorithm that\nis capable of computing a few smallest magnitude eigenvalues and their\ncorresponding left and right eigenvectors of a nonsymmetric matrix using only a\nsmall window of the BiCG residuals while simultaneously solving a linear system\nwith that matrix. For a system with multiple right-hand sides, we give an\nalgorithm that computes incrementally more eigenvalues while solving the first\nfew systems and then uses the computed eigenvectors to deflate BiCGStab for the\nremaining systems. Our experiments on various test problems, including Lattice\nQCD, show the remarkable ability of EigBiCG to compute spectral approximations\nwith accuracy comparable to that of the unrestarted, nonsymmetric Lanczos.\nFurthermore, our incremental EigBiCG followed by appropriately restarted and\ndeflated BiCGStab provides a competitive method for systems with multiple\nright-hand sides.",
        "positive": "Using $K^0\u03c0^-\\to\u03c0^-$ transitions to compute $K\\to(\u03c0\u03c0)_{I=0}$\n  decay amplitudes at NLO in the chiral expansion: It is proposed to compute matrix elements for the (unphysical) $K^0\\pi^-\\to\n\\pi^-$ transition to determine the next-to-leading order low energy constants\nof the weak chiral Lagrangian. This allows us to evaluate $K\\to(\\pi\\pi)_{I=0}$\ndecay amplitudes at this level of precision. This approach has several\nsignificant advantages over the use of $K\\to\\pi\\pi$ transitions, most notably\nthe elimination of s-channel disconnected diagrams and the use of fewer\ninversions."
    },
    {
        "anchor": "Random matrix model approach to chiral symmetry: We review the application of random matrix theory (RMT) to chiral symmetry in\nQCD. Starting from the general philosophy of RMT we introduce a chiral random\nmatrix model with the global symmetries of QCD. Exact results are obtained for\nuniversal properties of the Dirac spectrum: i) finite volume corrections to\nvalence quark mass dependence of the chiral condensate, and ii) microscopic\nfluctuations of Dirac spectra. Comparisons with lattice QCD simulations are\nmade. Most notably, the variance of the number of levels in an interval\ncontaining $n$ levels on average is suppressed by a factor $(\\log n)/\\pi^2 n$.\nAn extension of the random matrix model model to nonzero temperatures and\nchemical potential provides us with a schematic model of the chiral phase\ntransition. In particular, this elucidates the nature of the quenched\napproximation at nonzero chemical potential.",
        "positive": "A New Approach to Construct the Operator on Lattice for the Calculation\n  of Glueball Masses: We develop a new approach to construct the operator on lattice for the\ncalculation of glueball mass, which is based on the connection between the\ncontinuum limit of the chosen operator and the quantum number $J^{PC}$ of the\nstate studied. The spin of the state studied is then determined uniquely and\ndirectly in numerical simulation. Furthermore, the approach can be applied to\ncalculate the mass of glueball states (ground or excited states) with any spin\n$J$ including $J\\geq 4$. Under the quenched approximation, we present\npre-calculation results for the masses of $0^{++}$ state and $2^{++}$ state,\nwhich are $1754(85)(86)MeV$ and $2417(56)(117)MeV$, respectively."
    },
    {
        "anchor": "Lattice monopole action in pure SU(3) QCD: We obtain an almost perfect monopole action numerically after abelian\nprojection in pure SU(3) lattice QCD. Performing block-spin transformations on\nthe dual lattice, the action fixed depends only on a physical scale b. Monopole\ncondensation occurs for large b region. The numerical results show that\ntwo-point monopole interactions are dominant for large b. We next perform the\nblock-spin transformation analytically in a simplified case of two-point\nmonopole interactions with a Wilson loop on the fine lattice. The perfect\noperator evaluating the static quark potential on the coarse b-lattice are\nderived. The monopole partition function can be transformed into that of the\nstring model. The static potential and the string tension are estimated in the\nstring model framework. The rotational invariance of the static potential is\nrecovered, but the string tension is a little larger than the physical one.",
        "positive": "Supercurrent Renormalization in $\\mathcal{N}=1$ Supersymmetric\n  Yang-Mills Theory: In this work we study the renormalization of the SUSY Noether current in\nSupersymmetric $\\mathcal{N}$ = 1 Yang-Mills (SYM) theory on the lattice. In\nparticular, we study the mixing of the current with all other compatible\noperators of dimension 7/2 and 5/2, leading from the lattice-regularized to the\n$\\overline{\\rm MS}$-renormalized operator basis. We perform our task in two\nways:\n  (a) We compute, in dimensional regularization, the conversion factors\nrelating the $\\overline{\\rm MS}$ scheme to an intermediate gauge-invariant\ncoordinate-space scheme. In this second scheme, renormalization can be\nperformed via lattice simulations. This could help to investigate the breaking\nof SUSY on the lattice and strategies towards simulations of supersymmetric\nQCD. Here we present some preliminary numerical results.\n  (b) We use lattice perturbation theory and compute, to one loop, various two-\nand three-point functions. We consider mixing with all relevant\ngauge-noninvariant operators, which contain also ghost fields."
    },
    {
        "anchor": "Curvature of the chiral phase transition line from the magnetic equation\n  of state of (2+1)-flavor QCD: We analyze the dependence of the chiral phase transition temperature on\nbaryon number and strangeness chemical potentials by calculating the leading\norder curvature coefficients in the light and strange quark flavor basis as\nwell as in the conserved charge ($B, S$) basis. Making use of scaling\nproperties of the magnetic equation of state (MEoS) and including diagonal as\nwell as off-diagonal contributions in the expansion of the energy-like scaling\nvariable that enters the parametrization of the MEoS, allows to explore the\nvariation of $T_c(\\mu_B,\\mu_S) = T_c ( 1 - (\\kappa_2^B \\hat{\\mu}_B^2 +\n\\kappa_2^S \\hat{\\mu}_S^2 + 2\\kappa_{11}^{BS} \\hat{\\mu}_B \\hat{\\mu}_S))$ along\ndifferent lines in the $(\\mu_B,\\mu_S)$ plane. On lattices with fixed cut-off in\nunits of temperature, $aT=1/8$, we find $\\kappa_2^B=0.015(1)$,\n$\\kappa_2^S=0.0124(5)$ and $\\kappa_{11}^{BS}=-0.0050(7)$. We show that the\nchemical potential dependence along the line of vanishing strangeness chemical\npotential is about 10\\% larger than along the strangeness neutral line. The\nlatter differs only by about $3\\%$ from the curvature on a line of vanishing\nstrange quark chemical potential, $\\mu_s=0$. We also show that close to the\nchiral limit the strange quark mass contributes like an energy-like variable in\nscaling relations for pseudo-critical temperatures. The chiral phase transition\ntemperature decreases with decreasing strange quark mass, $T_c(m_s)=\nT_c(m_s^{\\rm phy}) (1 - 0.097(2) (m_s-m_s^{\\rm phys})/m_s^{\\rm phy}+{\\cal\nO}((\\Delta m_s)^2)$.",
        "positive": "Constraints on the Existence of Chiral Fermions in Interacting Lattice\n  Theories: It is shown that an interacting theory, defined on a regular lattice, must\nhave a vector-like spectrum if the following conditions are satisfied:\n(a)~locality, (b)~relativistic continuum limit without massless bosons, and\n(c)~pole-free effective vertex functions for conserved currents.\n  The proof exploits the zero frequency inverse retarded propagator of an\nappropriate set of interpolating fields as an effective quadratic hamiltonian,\nto which the Nielsen-Ninomiya theorem is applied."
    },
    {
        "anchor": "Aspects of scaling and scalability for flow-based sampling of lattice\n  QCD: Recent applications of machine-learned normalizing flows to sampling in\nlattice field theory suggest that such methods may be able to mitigate critical\nslowing down and topological freezing. However, these demonstrations have been\nat the scale of toy models, and it remains to be determined whether they can be\napplied to state-of-the-art lattice quantum chromodynamics calculations.\nAssessing the viability of sampling algorithms for lattice field theory at\nscale has traditionally been accomplished using simple cost scaling laws, but\nas we discuss in this work, their utility is limited for flow-based approaches.\nWe conclude that flow-based approaches to sampling are better thought of as a\nbroad family of algorithms with different scaling properties, and that\nscalability must be assessed experimentally.",
        "positive": "Creutz Ratios From Color-Truncated Lattice Configurations: We investigate whether information about Creutz ratios is encoded,\nseparately, in each gluon color component of numerically generated lattice\nconfigurations. Working in SU(2) lattice gauge theory in Landau gauge, we set\ntwo of the three gluon color components to zero, and compensate for the loss of\ntwo-thirds of the fluctuation by simply rescaling the remaining component by a\nfactor of $\\sqrt{3}$. Creutz ratios are then computed with this \"abelianized\"\nconfiguration. We find that the Creutz ratios of loops constructed from\nabelianized links converge to the usual Creutz ratios in the scaling regime."
    },
    {
        "anchor": "BRST-Symmetry Breaking and Bose-Ghost Propagator in Lattice Minimal\n  Landau Gauge: The Bose-ghost propagator has been proposed as a carrier of the confining\nforce in Yang-Mills theories in minimal Landau gauge. We present the first\nnumerical evaluation of this propagator, using lattice simulations for the\nSU(2) gauge group in the scaling region. Our data are well described by a\nsimple fitting function, which is compatible with an infrared-enhanced\nBose-ghost propagator. This function can also be related to a massive gluon\npropagator in combination with an infrared-free (Faddeev-Popov) ghost\npropagator. Since the Bose-ghost propagator can be written as the vacuum\nexpectation value of a BRST-exact quantity and should therefore vanish in a\nBRST-invariant theory, our results provide the first numerical manifestation of\nBRST-symmetry breaking due to restriction of gauge-configuration space to the\nGribov region.",
        "positive": "Universality and the Deconfinement Phase Transition in SU(2) Lattice\n  Gauge Theory: We study the three dimensional fundamental-adjoint $SU(2)$ lattice gauge\ntheory at non-zero temperatures by Monte Carlo simulations. On an $8^3 \\times\n2$ lattice, at $\\beta_A = 1.1$, where $\\beta_A$ is the adjoint coupling, we\nfind no evidence of any transition at the location of a previously known bulk\nphase transition around $\\beta = 1.33$. Moreover, the deconfinement transition\nat $ \\beta_A = 1.1$ occurs at $\\beta=1.20$ and is of first order for $\\beta_A\n\\ge 1.1$, thus implying a change of universality class from that of the Wilson\naction at $\\beta_A=0$. Computations of the plaquette susceptibility and the\ntemporal and spatial Polyakov loops on $8^3 \\times 4$ and $16^3 \\times 8$\nlattices at $\\beta_A = 1.1$ further support these conclusions and suggest that\nthe previously claimed bulk transition around $\\beta = 1.33$ is, in fact, the\nfirst order deconfinement transition. Simulations at larger $\\beta_A$ and the\nmeasurements of the mass gaps from the correlation functions of temporal and\nspatial Polyakov loops also confirm the temperature dependent nature of the\nabove transition. The consequences of our results on universality are\ndiscussed."
    },
    {
        "anchor": "The $N_f=2$ QCD chiral phase transition with Wilson fermions at zero and\n  imaginary chemical potential: The order of the thermal phase transition in the chiral limit of Quantum\nChromodynamics (QCD) with two dynamical flavors of quarks is a long-standing\nissue and still not known in the continuum limit. Whether the transition is\nfirst or second order has important implications for the QCD phase diagram and\nthe existence of a critical endpoint at finite densities. We follow a recently\nproposed approach to explicitly determine the region of first order chiral\ntransitions at imaginary chemical potential, where it is large enough to be\nsimulated, and extrapolate it to zero chemical potential with known critical\nexponents. Using unimproved Wilson fermions on coarse $N_t=4$ lattices, the\nfirst order region turns out to be so large that no extrapolation is necessary.\nThe critical pion mass $m_\\pi^c\\approx 560$ MeV is by nearly a factor 10 larger\nthan the corresponding one using staggered fermions. Our results are in line\nwith investigations of three-flavour QCD using improved Wilson fermions and\nindicate that the systematic error on the two-flavour chiral transition is\nstill of order 100\\%.",
        "positive": "Casimir scaling in G(2) lattice gauge theory: We computed potentials between static color sources from the six lowest\nrepresentations of G(2) lattice gauge theory, in numerical simulations with the\nWilson action on asymmetric lattices with nonperturbatively estimated values of\nthe bare anisotropy. We present evidence for (approximate) Casimir scaling of\nthe obtained intermediate string tensions. The agreement with the\nCasimir-scaling prediction improves by increasing the coupling beta in the\nweak-coupling region above the crossover observed in G(2) gauge theory. The\nresult naturally fits into confinement models with magnetic disorder and vacuum\ndomain structure, but may represent a challenge for other approaches."
    },
    {
        "anchor": "Reducing cutoff effects in maximally twisted lattice QCD close to the\n  chiral limit: When analyzed in terms of the Symanzik expansion, lattice correlators of\nmulti-local (gauge-invariant) operators with non-trivial continuum limit\nexhibit in maximally twisted lattice QCD ``infrared divergent'' cutoff effects\nof the type a^{2k}/(m_\\pi^2)^{h}, 2k\\geq h\\geq 1 (k,h integers), which tend to\nbecome numerically large when the pion mass gets small. We prove that, if the\naction is O(a) improved a` la Symanzik or, alternatively, the critical mass\ncounter-term is chosen in some ``optimal'' way, these lattice artifacts are\nreduced to terms that are at worst of the order a^{2}(a^2/m_\\pi^2)^{k-1}, k\\geq\n1. This implies that the continuum extrapolation of lattice results is smooth\nat least down to values of the quark mass, m_q, satisfying the order of\nmagnitude inequality m_q >a^2\\Lambda^3_{\\rm QCD}.",
        "positive": "Many flavor QCD as exploration of the walking behavior with the\n  approximate IR fixed point: We present the first report of the LatKMI collaboration on the the lattice\nQCD simulation performed at the KMI computer, \"$\\varphi$\", for the cases of 4\nflavors and 8 flavors, the latter being expected to be a candidate for the\nwalking technicolor having an approximate scale invariance near the infrared\nfixed point. The simulation was carried out based on the highly improved\nstaggered quark (HISQ) action. In this proceedings, we report preliminary\nresults on the spectrum, analyzed through the chiral perturbation theory and\nthe finite-size hyperscaling. We observe qualitatively different behavior of\nthe 8-flavor case in contrast to the 4-flavor case which shows clear indication\nof the hadronic phase as in the usual QCD."
    },
    {
        "anchor": "Two-photon decay of $\u03c0^0$ from two-flavor lattice QCD: We study the correction to the radiative $\\pi^0$ decay width due to finite\nlight quark mass. Using lattice QCD with the overlap fermion formulation, we\ncalculate the three-point function of the form $<PV_\\mu V_\\nu>$ in the\n(Euclidean) momentum space, which corresponds to the $\\pi^0\\rightarrow\n\\gamma^*\\gamma^*$ amplitude. To fit the lattice data, we use two different\nmodifications of vector meson dominance (VMD) ansatz. One is a combined form of\nVMD with the next-to-leading order (NLO) chiral perturbation theory (ChPT), and\nthe other is a resummed form of pion-loop diagrams. We extract one of the low\nenergy constants in NLO ChPT, and estimate $\\pi^0\\rightarrow \\gamma\\gamma$\ndecay width including finite mass correction.",
        "positive": "Exploring the Roper wave function in Lattice QCD: Using a correlation matrix analysis consisting of a variety of smearings, the\nCSSM Lattice collaboration has successfully isolated states associated with the\nRoper resonance and other \"exotic\" excited states such as the $\\Lambda(1405)$\non the lattice at near-physical pion masses. We explore the nature of the Roper\nby examining the eigenvectors that arise from the variational analysis,\ndemonstrating that the Roper state is dominated by the $\\chi_1$ nucleon\ninterpolator and only poorly couples to $\\chi_2.$ By examining the probability\ndistribution of the Roper on the lattice, we find a structure consistent with a\nconstituent quark model. In particular, the Roper $d$-quark wave function\ncontains a single node consistent with a $2S$ state. A detailed comparison with\nconstituent quark model wave functions is carried out, validating the approach\nof accessing these states by constructing a variational basis composed of\ndifferent levels of fermion source and sink smearing."
    },
    {
        "anchor": "The gluon propagator close to criticality: The deconfinement phase transition of pure Yang-Mills theory at finite\ntemperature is reflected in the behavior of gauge-fixed gluonic correlation\nfunctions. This is one of many examples of how physical information can be\nextracted from gauge-dependent correlations which is not always obvious. Here,\nwe study the behavior of the Landau-gauge gluon propagator of pure SU(2) across\nthe phase transition in 2+1 and 3+1 dimensions in order to assess to what\nextend the corresponding critical behavior is reflected in these correlations.\nWe discuss why it should emerge from a continuum perspective and test our\nexpectations in lattice simulations. A comparison with SU(3) furthermore\nreveals quite clear indications for a sensitivity of the gluon propagator to\nthe order of the transition.",
        "positive": "A Lattice Study of the Nucleon Excited States with Domain Wall Fermions: We present results of our numerical calculation of the mass spectrum for\nisospin one-half and spin one-half non-strange baryons, i.e. the ground and\nexcited states of the nucleon, in quenched lattice QCD. We use a new lattice\ndiscretization scheme for fermions, domain wall fermions, which possess almost\nexact chiral symmetry at non-zero lattice spacing. We make a systematic\ninvestigation of the negative-parity $N^*$ spectrum by using two distinct\ninterpolating operators at $\\beta=6/g^2=6.0$ on a $16^3 \\times 32 \\times 16$\nlattice. The mass estimates extracted from the two operators are consistent\nwith each other. The observed large mass splitting between this state,\n$N^*(1535)$, and the positive-parity ground state, the nucleon N(939), is well\nreproduced by our calculations. We have also calculated the mass of the first\npositive-parity excited state and found that it is heavier than the\nnegative-parity excited state for the quark masses studied."
    },
    {
        "anchor": "New Method for the Extrapolation of Finite-Size Data to Infinite Volume: We present a simple and powerful method for extrapolating finite-volume Monte\nCarlo data to infinite volume, based on finite-size-scaling theory. We discuss\ncarefully its systematic and statistical errors, and we illustrate it using\nthree examples: the two-dimensional three-state Potts antiferromagnet on the\nsquare lattice, and the two-dimensional $O(3)$ and $O(\\infty)$ $\\sigma$-models.\nIn favorable cases it is possible to obtain reliable extrapolations (errors of\na few percent) even when the correlation length is 1000 times larger than the\nlattice.",
        "positive": "Review of lattice results concerning low energy particle physics: We review lattice results relevant for pion and kaon physics with the aim of\nmaking them easily accessible to the particle physics community. Specifically,\nwe review the determination of the light-quark masses, the form factor f_+(0),\nrelevant for the semileptonic K -> pi transition at zero momentum transfer as\nwell as the ratio f_K/f_pi of decay constants and discuss the consequences for\nthe elements V_{us} and V_{ud} of the CKM matrix. Furthermore, we describe the\nresults obtained on the lattice for some of the low-energy constants of\nSU(2)_LxSU(2)_R and SU(3)_LxSU(3)_R Chiral Perturbation Theory and review the\ndetermination of the B_K parameter of neutral kaon mixing. We introduce quality\ncriteria and use these when forming averages. Although subjective and\nimperfect, these criteria may help the reader to judge different aspects of\ncurrent lattice computations. Our main results are summarized in section 1.2,\nbut we stress the importance of the detailed discussion that underlies these\nresults and constitutes the bulk of the present review."
    },
    {
        "anchor": "Density matrix renormalization group in a two-dimensional\n  $\u03bb\u03c6^4$ Hamiltonian lattice model: Density matrix renormalization group (DMRG) is applied to a (1+1)-dimensional\n$\\lambda\\phi^4$ model. Spontaneous breakdown of discrete $Z_2$ symmetry is\nstudied numerically using vacuum wavefunctions. We obtain the critical coupling\n$(\\lambda/\\mu^2)_{\\rm c}=59.89\\pm 0.01$ and the critical exponent\n$\\beta=0.1264\\pm 0.0073$, which are consistent with the Monte Carlo and the\nexact results, respectively. The results are based on extrapolation to the\ncontinuum limit with lattice sizes $L=250,500$, and 1000. We show that the\nlattice size L=500 is sufficiently close to the the limit $L\\to\\infty$.",
        "positive": "Vacuum State of Lattice Gauge Theory with Fermions in 2+1 Dimensions: We investigate the vacuum state of the lattice gauge theory with fermions in\n2+1 dimensions. The vacuum in the Hermite form for the fermion part is\nobtained; the vacuum in the unitary form has been proposed by Luo and Chen. It\nis shown that the Hermite vacuum has a lower energy than the unitary one\nthrough the variational method."
    },
    {
        "anchor": "Thermodynamics of strongly-coupled lattice QCD in the chiral limit: In the strong coupling limit, $n$-point functions in lattice QCD with\nstaggered fermions can be rewritten exactly as sums over constrained\nconfigurations of monomers, dimers, and baryon loops covering the spacetime\nlattice. Worm algorithms provide efficient global sampling methods over such\nensembles, and are particularly efficient in the chiral limit. We study the\nthermodynamics of strongly-coupled U(3) and SU(3) lattice QCD with one massless\nstaggered fermion using such methods, and compare the results with the\nrelativistic pion gas down to low temperatures O(15 MeV).",
        "positive": "Lattice QCD and heavy ion collisions: a review of recent progress: In the last few years, numerical simulations of QCD on the lattice have\nreached a new level of accuracy. A wide range of thermodynamic quantities is\nnow available in the continuum limit and for physical quark masses. This allows\na comparison with measurements from heavy ion collisions for the first time.\nFurthermore, calculations of dynamical quantities are also becoming available.\nThe combined effort from first principles and experiment allows us to gain an\nunprecedented understanding of the properties of quark-gluon plasma. I will\nreview the state-of-the-art results from lattice simulations and connect them\nto the experimental information from RHIC and the LHC."
    },
    {
        "anchor": "Electric Polarizability of Hadrons: The electric polarizability of a hadron allows an external electric field to\nshift the hadron mass. We try to calculate the electric polarizability for\nseveral hadrons from their quadratic response to the field at a=0.17fm using an\nimproved gauge field and the clover quark action. Results are compared to\nexperiment where available.",
        "positive": "Meson spectral functions at nonzero momentum in hot QCD: We present preliminary results for meson spectral functions at nonzero\nmomentum, obtained from quenched lattice QCD simulations at finite temperature\nusing the Maximal Entropy Method. Twisted boundary conditions are used to have\naccess to many momenta p~T. For light quarks, we observe a drastic modification\nwhen heating the system from below to above Tc. In particular, for the vector\nspectral density we find a nonzero spectral weight at all energies."
    },
    {
        "anchor": "Infrared fixed point of QCD, critical flavor number and triality\n  automorphism of octonions: We show that the discrepancy on the critical flavor number of fermions\n$N_f^c$ for the appearance of the infrared fixed point based on the t'Hooft\nanomaly matching condition and derived from the Schr\\\"odinger functional method\n($N_f^c\\sim 9)$ and the experimental analysis of the JLab group using Bjorken\nsum rule and GDH sum rule, and our lattice simulation($N_f^c\\sim 3$) could be\nresolved by assuming the topological structure of the infrared fixed point is\nnot that of $U(1)^3$ but that of $G_2$ with triality automorphism of octonions\nwhich appear in the product of quaternions.\n  The agreement of the infrared fixed point of the running coupling measured in\nlattice simulations with use of the quaternion real condition and the\nprediction of the BLM renormalization theory might be due to the boundary\ncondition on $S^3\\times R$ manifold of quaternion. The form factor of a proton\nmeasured via Ward identity through the difference of the inverse propagator at\nmomentum p+q/2 and at p-q/2 agrees with the phenomenological dipole fit.",
        "positive": "Power Counting Regime of Chiral Extrapolation and Beyond: Finite-range regularised (FRR) chiral effective field theory is presented in\nthe context of approximation schemes ubiquitous in modern lattice QCD\ncalculations. Using FRR techniques, the power-counting regime (PCR) of chiral\nperturbation theory can be estimated. To fourth-order in the expansion at the\n1% tolerance level, we find m_\\pi < 180 MeV for the PCR, extending only a small\ndistance beyond the physical pion mass."
    },
    {
        "anchor": "Pure SU(3) lattice gauge theory using operators and states: We study pure SU(3) gauge theory on a large lattice, using Schrodinger's\nequation. Our approximate solution uses a basis of roughly 1000 states. Gauge\ninvariance is recovered when the color content of the ground state is\nextrapolated to zero. We are able to identify the gauge invariant excitations\nthat remain when the extrapolation is performed. In the weak coupling limit, we\nobtain promising results when we compare the excitation energies (masses) to\nknown results, which we derive. We discuss the application of our\nnonperturbative method to the regime where glueballs are present.",
        "positive": "Improved Spectroscopy of Minimal Walking Technicolor: We present an improved study of spectroscopic observables in the $SU(2)$\nYang-Mills theory with two adjoint fermions. We make an improvement on the\nprecision of previous results which clarify the scale of finite volume effects\npresent. This analysis adds to the evidence for near-conformal dynamics of this\ntheory, while indicating a preference for a low anomalous mass dimension of the\nmassless theory."
    },
    {
        "anchor": "Direct detection of metal-insulator phase transitions using the modified\n  Backus-Gilbert method: The detection of the (semi)metal-insulator phase transition can be extremely\ndifficult if the local order parameter which characterizes the ordered phase is\nunknown.In some cases, it is even impossible to define a local order parameter:\nthe most prominent example of such system is the spin liquid state. This state\nwas proposed to exist in theHubbard model on the hexagonal lattice in a region\nbetween the semimetal phase and the antiferromagnetic insulator phase. The\nexistence of this phase has been the subject of a long debate. In order to\ndetect these exotic phases we must use alternative methods to those used for\nmore familiar examples of spontaneous symmetry breaking. We have modified the\nBackus-Gilbert method of analytic continuation which was previously used in the\ncalculation of the pion quasiparticle mass in lattice QCD. The modification of\nthe method consists of the introduction of the Tikhonov regularization scheme\nwhich was used to treat the ill-conditioned kernel. This modified\nBackus-Gilbert method is applied to the Euclidean propagators in momentum space\ncalculated using the hybridMonte Carlo algorithm. In this way, it is possible\nto reconstruct the full dispersion relation and to estimate the mass gap, which\nis a direct signal of the transition to the insulating state. We demonstrate\nthe utility of this method in our calculations for the Hubbard model on the\nhexagonal lattice. We also apply the method to the metal-insulator phase\ntransition in the Hubbard-Coulomb model on the square lattice.",
        "positive": "Noise reduction algorithm for Glueball correlators: We present an error reduction method for obtaining glueball correlators from\nmonte carlo simulations of SU(3) lattice gauge theory. We explore the scalar\nand tensor channels at three different lattice spacings. Using this method we\ncan follow glueball correlators to temporal separations even up to 1 fermi. We\nestimate the improvement over the naive method and compare our results with\nexisting computations."
    },
    {
        "anchor": "Vector condensation in QCD: The response of the QCD vacuum to quark chemical potentials on the order of\nthe pion mass is studied within the context of chiral perturbation theory. For\ntwo colour QCD diquark condensation sets in when the baryon chemical potential\nbecomes larger than the pion mass. This leading order result is confirmed at\nnext to leading order. Next a set of massive spin-one vectors is included in\nthe effective Lagrangian and the vector masses are calculated at leading order.\nMassless vector modes appear when the baryon chemical potential is equal to the\nmass of the lightest vector at zero chemical potential. This suggest vector\ncondensation.",
        "positive": "Vortices in the SU(2)-Higgs model -- Vortices and the covariant adjoint\n  Laplacian: Vortices in the SU(2)--Higgs model: The presence of a fundamental Higgs in\nthe SU(N)-Higgs model yields color screening at some finite distance. Whereas\nthe transition to the Higgs \"phase\" is accompanied by a suppression of\nprojected center vortices, there is nearly no influence of color screening on\nthe vortex properties in the confined \"phase\". Hence the behavior of the Wilson\nloop can be described in both phases within the vortex picture of confinement.\n  Vortices and the covariant adjoint Laplacian: Laplacian center gauge is a\nmethod to localize center vortices in SU(N) gauge theory. We show that the\neigenvectors of the covariant adjoint Laplacian identify vortices for a special\nclass of gauge field configurations. However, for Monte Carlo generated\nconfigurations, modified approaches are required."
    },
    {
        "anchor": "Calculation of $K \\to \u03c0\u03c0$ decay amplitudes with improved Wilson\n  fermion action in lattice QCD: We present our result for the $K\\to\\pi\\pi$ decay amplitudes for both the\n$\\Delta I=1/2$ and $3/2$ processes with the improved Wilson fermion action.\nExpanding on the earlier works by Bernard {\\it et al.} and by Donini {\\it et\nal.}, we show that mixings with four-fermion operators with wrong chirality are\nabsent even for the Wilson fermion action for the parity odd process in both\nchannels due to CPS symmetry. Therefore, after subtraction of an effect from\nthe lower dimensional operator, a calculation of the decay amplitudes is\npossible without complications from operators with wrong chirality, as for the\ncase with chirally symmetric lattice actions. As a first step to verify the\npossibility of calculations with the Wilson fermion action, we consider the\ndecay amplitudes at an unphysical quark mass $m_K \\sim 2 m_\\pi$. Our\ncalculations are carried out with $N_f=2+1$ gauge configurations generated with\nthe Iwasaki gauge action and nonperturbatively $O(a)$-improved Wilson fermion\naction at $a=0.091\\,{\\rm fm}$, $m_\\pi=280\\,{\\rm MeV}$, and $m_K=580\\,{\\rm MeV}$\non a $32^3\\times 64$ ($La=2.9\\,{\\rm fm}$) lattice. For the quark loops in the\npenguin and disconnected contributions in the $I=0$ channel, the combined\nhopping parameter expansion and truncated solver method work very well for\nvariance reduction. We obtain, for the first time with a Wilson-type fermion\naction, that ${\\rm Re}A_0 = 60(36) \\times10^{ -8}\\,{\\rm GeV}$ and ${\\rm Im}A_0\n=-67(56) \\times10^{-12}\\,{\\rm GeV}$ for a matching scale $q^* =1/a$. The\ndependence on the matching scale $q^*$ for these values is weak.",
        "positive": "Perturbative renormalization for static and domain-wall bilinears and\n  four-fermion operators with improved gauge actions: We calculate one-loop renormalization factors for heavy-light bilinears as\nwell as four-fermion operators relevant for $B^{0} - \\bar{B}^{0}$ mixing\ncalculations on the lattice. We use the static approximation for heavy quarks\nand the domain-wall formulation for light quarks. We present results for\ndifferent choices of improved gauge action."
    },
    {
        "anchor": "Chiral Symmetry, Renormalization Group and Fixed Points for Lattice\n  Fermions: We discuss fixed point actions for various types of free lattice fermions.\nThe iterated block spin renormalization group transformation yields lines of\nlocal but chiral symmetry breaking fixed points. For staggered fermions at\nleast the $U(1) \\otimes U(1)$ symmetry can be preserved. This provides a basis\nfor approximating perfect actions for asymptotically free theories far from the\ncritical surface. For a class of lattice fermions that includes Wilson fermions\nwe find in addition one non local but chirally invariant fixed point. Its\nvicinity is studied in the framework of the Gross Neveu model with weak four\nFermi interaction.",
        "positive": "Problems with the Quenched Approximation in the Chiral Limit: In the quenched approximation, loops of the light singlet meson (the $\\eta'$)\ngive rise to a type of chiral logarithm absent in full QCD. These logarithms\nare singular in the chiral limit throwing doubt upon the utility of the\nquenched approximation. In previous work, I summed a class of diagrams, leading\nto non-analytic power dependencies such as $\\cond\\propto\nm_q^{-\\delta/(1+\\delta)}$. I suggested, however, that these peculiar results\ncould be redefined away. Here I give an alternative derivation of the results,\nbased on the renormalization group, and argue that they cannot be redefined\naway. I discuss the evidence (or lack thereof) for such effects in numerical\ndata."
    },
    {
        "anchor": "Comments on lattice gauge theories with infrared-attractive fixed points: Theories of interacting gauge fields and fermions can possess a running gauge\ncoupling with an infrared attractive fixed point (IRFP). We present a minimal\ndescription of the physics of these systems and comment on some simple\nexpectations for results from lattice simulations done within the basin of\nattraction of the IRFP in these theories.",
        "positive": "Quantization of empty space: We suggest to use \"minimal\" choice of quantum gravity theory, that is the\nquantum field theory, in which space-time is seen as Riemannian space and\nmetric (or vierbein field) is the dynamical variable. We then suggest to use\nthe simplest acceptable action, that is the squared curvature action. The\ncorrespondent model is renormalizable, has the correct classical limit without\nmatter and can be explored using Euclidian path integral formalism. In order to\nget nonperturbative results one has to put this model on the lattice. While\ndoing so serious problems with measure over dynamical variables are\nencountered, which were not solved until present. We suggest to solve them\nusing the representation of Riemannian space as a limiting case of Riemann -\nCartan space, where the Poincare group connection plays the role of dynamical\nvariable. We construct manifestly gauge invariant discretization of Riemann -\nCartan space. Lattice realization of Poincare gauge transformation naturally\nacts on the dynamical variables of the constructed discretization. There exists\nlocal measure invariant under this gauge transformation, which could be used as\na basic element of lattice path integral methods. The correspondent lattice\nmodel appears to be useful for numerical simulations."
    },
    {
        "anchor": "Determination of c_sw in N_f=3+1 Lattice QCD with massive Wilson\n  fermions: We develop a strategy for the non-perturbative determination of the\nO(a)-improvement coefficient c_sw for Wilson fermions with massive sea quarks.\nThe improvement condition is defined via the PCAC relation in the Schr\\\"odinger\nfunctional. It is imposed along a line of constant physics designed to be close\nto the correct mass of the charm quark. The numerical work uses the tree-level\nimproved L\\\"uscher-Weisz gauge action in N_f=3+1 Lattice QCD.",
        "positive": "Topology and Chiral Symmetry in QCD with Overlap Fermions: We briefly review the overlap formalism for chiral gauge theories, the\noverlap Dirac operator for massless fermions and its connection to domain wall\nfermions. We describe properties of the overlap Dirac operator, and methods to\nimplement it numerically. Finally, we give some examples of quenched\ncalculations of chiral symmetry breaking and topology with overlap fermions."
    },
    {
        "anchor": "High statistics calculations of quenched QCD spectrum using various\n  quark sources: We present the results for the hadron spectrum calculated on 400\nconfigurations using point source, wall source and 8-cubic sources, in quenched\nQCD with Wilson fermions at $\\beta=6.0$ and $K=0.155$ on a $24^3 \\times 54$\nlattice. The results for the ground state masses obtained with three types of\nquark sources agree well with each other. Masses of the first excited states\nappear consistent with experimental values within large errors.",
        "positive": "A Hamiltonian lattice study of the two-dimensional Wess-Zumino model: We investigate a Hamiltonian lattice version of the two-dimensional\nWess-Zumino model by Quantum Monte Carlo simulations. In order to study the\npattern of supersymmetry breaking, we measure the ground state energy and the\ncorrelation length along a trajectory approaching the continuum limit. The\nalgorithm is very effective in measuring the ground state energy, and adequate\nfor the correlation length."
    },
    {
        "anchor": "Numerical determination of the $\u039b$-parameter in SU(3) gauge theory\n  from the twisted gradient flow coupling: We estimate the $\\Lambda$-parameter in the $\\overline{\\mathrm{MS}}$ scheme\nfor the SU(3) pure gauge theory with the twisted gradient flow method\nnon-perturbatively. We obtain\n$\\Lambda_{\\overline{\\mathrm{MS}}}/\\sqrt{\\sigma}=0.527(13)(10)$ and\n$r_{0}\\Lambda_{\\overline{\\mathrm{MS}}}=0.605(15)(5)$ which are consistent with\nthe known values.This demonstrates the validity of the present method.",
        "positive": "Signal-to-noise improvement through neural network contour deformations\n  for 3D $SU(2)$ lattice gauge theory: Complex contour deformations of the path integral have been demonstrated to\nsignificantly improve the signal-to-noise ratio of observables in previous\nstudies of two-dimensional gauge theories with open boundary conditions. In\nthis work, new developments based on gauge fixing and a neural network\ndefinition of the deformation are introduced, which enable an effective\napplication to theories in higher dimensions and with generic boundary\nconditions. Improvements of the signal-to-noise ratio by up to three orders of\nmagnitude for Wilson loop measurements are shown in $SU(2)$ lattice gauge\ntheory in three spacetime dimensions."
    },
    {
        "anchor": "Interfaces in hot gauge theory: The string tension at low T and the free energy of domain walls at high T can\nbe computed from one and the same observable. We show by explicit calculation\nthat domain walls in hot Z(2) gauge theory have good thermodynamical behaviour.\nThis is due to roughening of the wall, which expresses the restoration of\ntranslational symmetry.",
        "positive": "Spectral density calculations in a heavy-light meson-meson system: A system of two static quarks, at fixed distances r, and two light quarks is\nstudied on an anisotropic lattice. Excitations by operators emphasizing quark\nor gluon degrees of freedom are examined. The maximum entropy method is applied\nin the spectral analysis. These simulations ultimately aim at learning about\nmechanisms of hadronic interaction."
    },
    {
        "anchor": "Thermodynamic properties of QCD in external magnetic fields: We consider the effect of strong external electromagnetic fields on\nthermodynamic observables in QCD, through lattice simulations with 1+1+1\nflavors of staggered quarks at physical quark masses. Continuum extrapolated\nresults are presented for the light quark condensates and for their tensor\npolarizations, as functions of the temperature and the magnetic field. We find\nthe light condensates to undergo inverse magnetic catalysis in the transition\nregion, in a manner that the transition temperature decreases with growing\nmagnetic field. We also compare the results to other approaches and lattice\nsimulations. Furthermore, we relate the tensor polarization to the spin part of\nthe magnetic susceptibility of the QCD vacuum, and show that this contribution\nis diamagnetic.",
        "positive": "Analytic continuation of the critical line in 2-color QCD at nonzero\n  temperature and density: We determine the pseudo-critical line in the temperature - chemical potential\nplane of 2-color QCD by direct Monte Carlo simulations and by analytic\ncontinuation from imaginary chemical potential."
    },
    {
        "anchor": "Brief Review of Multicanonical Simulations: Recent progress of simulations with non-canonical weight factors is\nsummarized.",
        "positive": "Low and high spin mesons from $N_f=2$ Clover-Wilson lattices: We present results for excited meson spectra from $N_f=2$ clover-Wilson\nconfigurations provided by the CP-PACS Collaboration. In our study we\ninvestigate both low and high spin mesons. For spin-0 and spin-1 mesons, we are\nespecially interested in the excited states. To access these states we\nconstruct several different interpolators from quark sources of different\nspatial smearings and calculate a matrix of correlators. For this matrix we\nthen solve a generalized eigenvalue problem. For spin-2 and spin-3, we extract\nonly the lowest lying states."
    },
    {
        "anchor": "Constant contribution in meson correlators at finite temperature: We discuss a constant contribution to meson correlators at finite\ntemperature. In the deconfinement phase of QCD, a colored single quark state is\nallowed as a finite energy state, which yields to a contribution of wraparound\nquark propagation to temporal meson correlators. We investigate the effects in\nthe free quark case and quenched QCD at finite temperature. The ``scattering''\ncontribution causes a constant mode in meson correlators with zero spatial\nmomentum and degenerate quark masses, which can dominate the correlators in the\nregion of large imaginary times. In the free spectral function, the\ncontribution yields a term proportional to $\\omega\\delta(\\omega)$. Therefore\nthis contribution is related to transport phenomena in the quark gluon plasma.\nIt is possible to distinguish the constant contribution from the other part\nusing several analysis methods proposed in this paper. As a result of the\nanalyses, we find that drastic changes in charmonium correlators for $\\chi_c$\nstates just above the deconfinement transition are due to the constant\ncontribution. The other differences in the $\\chi_c$ states are small. It may\nindicate the survival of $\\chi_c$ states after the deconfinement transition\nuntil, at least, $1.4T_c$.",
        "positive": "On the color structure of Yang-Mills theory with static sources in a\n  periodic box: We present an exploratory numerical study on the lattice of the color\nstructure of the wave functionals of the SU(3) Yang-Mills theory in the\npresence of a $q\\bar q$ static pair. In a spatial box with periodic boundary\nconditions we discuss the fact that all states contributing to the Feynman\npropagation kernel are global color singlets. We confirm this numerically by\ncomputing the correlations of gauge-fixed Polyakov lines with color-twisted\nboundary conditions in the time direction. The values of the lowest energies in\nthe color singlet and octet external source sectors agree within statistical\nerrors, confirming that both channels contribute to the lowest (global singlet)\nstate of the Feynman kernel. We then study the case of homogeneous boundary\nconditions in the time direction for which the gauge-fixing is not needed. In\nthis case the lowest energies extracted in the singlet external source sector\nagree with those determined with periodic boundary conditions, while in the\noctet sector the correlator is compatible with being null within our\nstatistical errors. Therefore consistently only the singlet external source\ncontribution has a non-vanishing overlap with the null-field wave functional."
    },
    {
        "anchor": "Nucleon Charges, Form-factors and Neutron EDM: We present an update of our analysis of statistical and systematic errors in\nthe calculation of iso-vector scalar, axial and tensor charges of the nucleon.\nThe calculations are done using $N_f=2+1+1$ flavor HISQ ensembles generated by\nthe MILC Collaboration at three values of the lattice spacing ($a=0.12,\\ 0.09,$\nand $0.06$ fm) and three values of the quark mass ($M_\\pi \\approx 310,\\ 220$\nand $130$ MeV); and clover fermions for calculating the correlation functions,\ni.e., we use a clover-on-HISQ lattice formulation. The all-mode-averaging\nmethod allows us to increase the statistics by a factor of eight for the same\ncomputational cost leading to a better understanding of and control over\nexcited state contamination. Our current results, after extrapolation to the\ncontinuum limit and physical pion mass are $g_A^{u-d} = 1.21(3)$, $g_T^{u-d} =\n1.005(59)$ and $g_S^{u-d} = 0.95(12) $. Further checks of control over all\nsystematic errors, especially in $g_A^{u-d}$, are still being performed. Using\nresults for the flavor-diagonal charges, $g_T^{u} $, $g_T^{d} $ and $g_T^{s}$,\nwe analyze contributions of the quark electric dipole moment to the neutron EDM\nand the consequences for split SUSY model.",
        "positive": "Nature of the finite temperature transition in QCD with strange quark: The finite temperature transition in QCD is studied using Wilson quarks for\nthe cases of $N_F=2$, 3 and 2+1. For $N_F=2$ the transition is smooth in the\nchiral limit on both $\\nt=4$ and 6 lattices. For $N_F=3$, clear two state\nsignals are observed for $\\beta\\leq4.7$ on $8^2\\times10 \\times4$ and\n$12^3\\times4$ lattices, which implies the transition is first order for $m_q\n\\simm{<} 140$ MeV. For $N_F=2+1$ we study two cases of $m_s \\simeq 150$ and 400\nMeV with $m_u=m_d \\simeq 0$. In contrast to a previous result with staggered\nquarks, two state signals are clearly observed for both cases, suggesting a\nfirst order QCD phase transition in the real world."
    },
    {
        "anchor": "Formulating Light Cone QCD on the Lattice: We present the near light cone Hamiltonian $H$ in lattice QCD depending on\nthe parameter $\\eta$, which gives the distance to the light cone. Since the\nvacuum has zero momentum we can derive an effective Hamiltonian $H_{eff}$ from\n$H$ which is only quadratic in the momenta and therefore solvable by standard\nmethods. An approximate ground state wave functional is determined\nvariationally in the limit $\\eta \\to 0$.",
        "positive": "Lattice QCD Green's functions in maximally Abelian gauge: infrared\n  Abelian dominance and the quark sector: On lattice gauge field configurations with 2+1 dynamical quark flavors, we\ninvestigate the momentum space quark and gluon propagators in the combined\nmaximally Abelian plus $U(1)_3\\times U(1)_8$ Landau gauge. We extract the gluon\nfields from the lattice link variables and study the diagonal and off-diagonal\ngluon propagators. We find that the infrared region of the transverse diagonal\ngluon propagator is strongly enhanced compared to the off-diagonal propagator.\nThe Dirac operator from the Asqtad action is inverted on the diagonal and\noff-diagonal gluon backgrounds separately. In agreement with the hypothesis of\ninfrared Abelian dominance, we find that the off-diagonal gluon background\nhardly gives rise to any non-trivial quark dynamics while the quark propagator\nfrom the diagonal gluon background closely resembles its Landau gauge\ncounterpart."
    },
    {
        "anchor": "Finite-density QCD transition in magnetic field background: Using numerical simulations of lattice QCD with physical quark masses, we\nreveal the influence of magnetic-field background on chiral and deconfinement\ncrossovers in finite-temperature QCD at low baryonic density. In the absence of\nthermodynamic singularity, we identify these transitions with inflection points\nof the approximate order parameters: normalized light-quark condensate and\nrenormalized Polyakov loop, respectively. We show that the quadratic curvature\nof the chiral transition temperature in the ``temperature--chemical potential''\nplane depends rather weakly on the strength of the background magnetic field.\nAt weak magnetic fields, the thermal width of the chiral crossover gets\nnarrower as the density of the baryon matter increases, possibly indicating a\nproximity to a real thermodynamic phase transition. Remarkably, the curvature\nof the chiral thermal width flips its sign at $eB_{\\mathrm{fl}} \\simeq\n0.6\\,\\mathrm{GeV}^2$, so that above the flipping point $B > B_{\\mathrm{fl}}$,\nthe chiral width gets wider as the baryon density increases. Approximately at\nthe same strength of magnetic field, the chiral and deconfining crossovers\nmerge together at $T \\approx 140\\,\\mathrm{MeV}$. The phase diagram in the\nparameter space ``temperature-chemical potential-magnetic field'' is outlined,\nand single-quark entropy and single-quark magnetization are explored. The\ncurvature of the chiral thermal width allows us to estimate an approximate\nposition of the chiral critical endpoint at zero magnetic field:\n$(T_c^{\\text{CEP}}, \\mu_B^{\\text{CEP}})= (100(25)\\, \\text{MeV},\\\n800(140)\\,\\text{MeV})$.",
        "positive": "The scaling functions of the free energy density and its derivatives for\n  the 3d O(4) model: We derive direct representations of the scaling functions of the 3d O(4)\nmodel which are relevant for comparisons to other models, in particular QCD.\nThis is done in terms of expansions in the scaling variable z= t/h^{1/Delta}.\nThe expansions around z=0 and the corresponding asymptotic ones for z --> +-\ninfinity overlap such that no interpolation is needed. The expansion\ncoefficients are determined numerically from the data of a previous high\nstatistics simulation of the O(4) model on a three-dimensional lattice of\nlinear extension L=120. From the scaling function of the magnetization we\ncalculate the leading asymptotic coefficients of the scaling function of the\nfree energy density. As a result we obtain the universal amplitude ratio\nA^+/A^-=1.84(4) for the specific heat. Comparing the scaling function of the\nenergy density to the data we find the non-singular part of the energy density\nepsilon_{ns}(T) with high precision and at the same time excellent scaling\nproperties."
    },
    {
        "anchor": "Theta term instead of the Higgs field in Electroweak theory: We consider the electroweak theory without fundamental scalar field. The\ntopological excitation of the SU(2)*U(1) theory (the monopole) plays the role\nof the Higgs field, it carries the SU(2)*U(1) topological charge due to the\ntheta--term of the special type.",
        "positive": "Matter near to the Endpoint of the Electroweak Phase Transition: Wave functions and the screening mass spectrum in the 3D SU(2)-Higgs model\nnear to the phase transition line below the endpoint and in the crossover\nregion are calculated. In the crossover region the changing spectrum versus\ntemperature is examined showing the aftermath of the phase transition at lower\nHiggs mass. Large sets of operators with various extensions are used allowing\nto identify wave functions in position space."
    },
    {
        "anchor": "Preliminary heavy-light decay constants from the MILC collaboration: Preliminary results from the MILC collaboration for $f_B$, $f_{B_s}$, $f_D$,\n$f_{D_s}$ and their ratios are presented. We compute in the quenched\napproximation at $\\beta=6.3$, 6.0 and 5.7 with Wilson light quarks and static\nand Wilson heavy quarks. We attempt to quantify systematic errors due to finite\nvolume, finite lattice spacing, large $am$, and fitting and extrapolation\nuncertainties. The hopping parameter approach of Henty and Kenway is used to\ntreat the heavy quarks; the sources are Coulomb gauge gaussians.",
        "positive": "A Lattice Study of Semi-leptonic Decays of $D$-Mesons: We present results of a lattice computation of the matrix elements of the\nvector and axial-vector currents which are relevant for the semi-leptonic\ndecays $D \\rightarrow K$ and $D \\rightarrow K^*$. The computations are\nperformed in the quenched approximation to lattice QCD on a $24^3 \\times 48$\nlattice at $\\beta=6.2$ using an $O(a)$-improved fermionic action."
    },
    {
        "anchor": "Meson Screening Masses at high Temperature in quenched QCD with improved\n  Wilson Quarks: We report on a lattice investigation of improved quenched Wilson fermions\nabove and below the confinement-deconfinement phase transition. Results on\nmeson screening masses as well as spatial wave functions are presented.\nMoreover, the meson dispersion relation is studied. Below the critical\ntemperature we do not observe any significant temperature effect while above\n$T_c$ the data are consistent with a leading free quark behavior.",
        "positive": "Phase diagram of the G(2) Higgs model and G(2)-QCD: We investigate gauge theories based on the smallest exceptional simple lie\ngroup G(2). Our first model considered here is G(2) Yang-Mills coupled to a\nfundamental Higgs field. In 4 spacetime dimensions we explore the phase diagram\nof the theory, showing that at larger Higgs masses the first order\ndeconfinement phase transition turns into a crossover and therefore connects\nthe low temperature confined phase with the high temperature deconfined phase.\nThe second model investigated is G(2) Yang-Mills coupled to fundamental\nfermions. It shares many features with QCD, especially fermionic baryons, but\ndue to the absence of the fermion sign problem we can investigate this theory\nwith Monte Carlo techniques even at low temperature and high baryonic density.\nFirst results on small lattices are presented."
    },
    {
        "anchor": "Tensor networks for High Energy Physics: contribution to Snowmass 2021: Tensor network methods are becoming increasingly important for high-energy\nphysics, condensed matter physics and quantum information science (QIS). We\ndiscuss the impact of tensor network methods on lattice field theory, quantum\ngravity and QIS in the context of High Energy Physics (HEP). These tools will\ntarget calculations for strongly interacting systems that are made difficult by\nsign problems when conventional Monte Carlo and other importance sampling\nmethods are used. Further development of methods and software will be needed to\nmake a significant impact in HEP. We discuss the roadmap to perform quantum\nchromodynamics (QCD) related calculations in the coming years. The research is\nlabor intensive and requires state of the art computational science and\ncomputer science input for its development and validation. We briefly discuss\nthe overlap with other science domains and industry.",
        "positive": "3 Into 2 Doesn't Go: (almost) chiral gauge theory on the lattice: Kaplan recently proposed a novel lattice chiral gauge theory in which the\nbare theory is defined on $(2n+1)$-dimensions, but the continuum theory emerges\nin $2n$-dimensions. We explore whether the resulting theory reproduces all the\nfeatures of continuum chiral gauge theory in the case of two-dimensional axial\nSchwinger model. We find that one can arrange for the two-dimensional\nperturbation expansion to be reproduced successfully. However, the theory fails\nto reproduce the 2-dimensional fermion nonconservation."
    },
    {
        "anchor": "Conserved Charge Fluctuations from Lattice QCD and the Beam Energy Scan: We discuss the next-to-leading order Taylor expansion of ratios of cumulants\nof net-baryon number fluctuations. We focus on the relation between the\nskewness ratio, $S_B\\sigma_B = \\chi_3^B/\\chi_1^B$, and the kurtosis ratio,\n$\\kappa_B\\sigma_B^2 =\\chi_4^B/\\chi_2^B$. We show that differences in these two\ncumulant ratios are small for small values of the baryon chemical potential.\nThe next-to-leading order correction to $\\kappa_B\\sigma_B^2$ however is\napproximately three times larger than that for $S_B\\sigma_B$. The former thus\ndrops much more rapidly with increasing beam energy, $\\sqrt{s_{NN}}$. We argue\nthat these generic patterns are consistent with current data on cumulants of\nnet-proton number fluctuations measured by the STAR Collaboration at\n$\\sqrt{s_{NN}}\\ge 19.6$~GeV.",
        "positive": "Exploring the HMC trajectory-length dependence of autocorrelation times\n  in lattice QCD: We study autocorrelation times of physical observables in lattice QCD as a\nfunction of the molecular dynamics trajectory length in the hybrid Monte-Carlo\nalgorithm. In an interval of trajectory lengths where energy and reversibility\nviolations can be kept under control, we find a variation of the integrated\nautocorrelation times by a factor of about two in the quantities of interest.\nTrajectories longer than conventionally used are found to be superior both in\nthe Nf=0 and Nf=2 examples considered here. We also provide evidence that they\nlead to faster thermalization of systems with light quarks."
    },
    {
        "anchor": "Non-trivial phase structure of $N_f=3$ QCD with $O(a)$-improved Wilson\n  fermion at zero temperature: JLQCD collaboration recently started the $N_f=3$ QCD simulations with the\n$O(a)$-improved Wilson fermion action employing an exact fermion algorithm\ndeveloped for odd number of quark flavors. It is found that this theory has an\nunexpected non-trivial phase structure in the $(\\beta,\\kappa)$ plane even at\nzero temperature. A detailed study is made to understand the nature of the\nobserved phase transitions and to find the way of avoiding untolerably large\nlattice artifacts associated with the phase transition.",
        "positive": "Linking continuum and lattice quark mass functions via an effective\n  charge: The quark mass function is computed both by solving the quark propagator\nDyson-Schwinger equation and from lattice simulations implementing overlap and\nDomain-Wall fermion actions for valence and sea quarks, respectively. The\nresults are confronted and seen to produce a very congruent picture, showing a\nremarkable agreement for the explored range of current-quark masses. The\neffective running-interaction is based on a process-independent charge rooted\non a particular truncation of the Dyson-Schwinger equations in the gauge\nsector, establishing thus a link from there to the quark sector and inspiring a\ncorrelation between the emergence of gluon and hadron masses."
    },
    {
        "anchor": "A numerical study of Goldstone-mode effects and scaling functions of the\n  three-dimensional O(2) model: We investigate numerically the three-dimensional O(2) model on 8^3-160^3\nlattices as a function of the magnetic field H. In the low-temperature phase we\nverify the H-dependence of the magnetization M induced by the Goldstone modes\nand determine M in the thermodynamic limit on the coexistence line both by\nextrapolation and by chiral perturbation theory. We compute two critical\namplitudes from the scaling behaviours on the coexistence line and on the\ncritical line. In both cases we find negative corrections to scaling. With\nadditional high temperature data we calculate the scaling function and show\nthat it has a smaller slope than that of the O(4) model. For future tests of\nQCD lattice data we study as well finite-size-scaling functions.",
        "positive": "Monte Carlo Renormalization Group analysis of QCD in two dimensional\n  coupling space: We report our results of the Monte Carlo Renormalization Group analysis in\ntwo dimensional coupling space. The qualitative features of the RG flow are\ndescribed with a phenomenological RG equation. The dependence on the lattice\nspacing for various actions provides the conditions to determine the parameters\nentering the RG equation."
    },
    {
        "anchor": "Exploring Three Nucleon Forces in Lattice QCD: We study the three nucleon force in Nf=2 dynamical clover fermion lattice\nQCD, utilizing the Nambu-Bethe-Salpeter wave function of the three nucleon\nsystem. Since parity-odd two nucleon potentials are not available in lattice\nQCD at this moment, we develop a new formulation to extract the genuine three\nnucleon force which requires only the information of parity-even two nucleon\npotentials. In order to handle the extremely expensive calculation cost, we\nconsider a specific three-dimensional coordinate configuration for the three\nnucleons. We find that the linear setup is advantageous, where nucleons are\naligned linearly with equal spacings. The lattice calculation is performed with\n16^3 x 32 configurations at \\beta=1.95, m_\\pi=1.13 GeV generated by CP-PACS\nCollaboration, and the result of the three nucleon force in triton channel is\npresented.",
        "positive": "Odd-flavor Hybrid Monte Carlo Algorithm for Lattice QCD: We discuss hybrid Monte Carlo algorithms for odd-flavor lattice QCD\nsimulations. The algorithms include a polynomial approximation which enables us\nto simulate odd-flavor QCD in the framework of the hybrid Monte Carlo\nalgorithm. In order to make the algorithms exact, the correction factor to the\npolynomial approximation is also included in an economical, stochastic way. We\ntest the algorithms for $n_f=1$, 1+1 and 2+1 flavors and compare results with\nother algorithms."
    },
    {
        "anchor": "The construction of generalized Dirac operators on the lattice: We discuss the steps to construct Dirac operators which have arbitrary\nfermion offsets, gauge paths, a general structure in Dirac space and satisfy\nthe basic symmetries (gauge symmetry, hermiticity condition, charge\nconjugation, hypercubic rotations and reflections) on the lattice. We give an\nextensive set of examples and offer help to add further structures.",
        "positive": "Extracting Nucleon Magnetic Moments and Electric Polarizabilities from\n  Lattice QCD in Background Electric Fields: Nucleon properties are investigated in background electric fields. As the\nmagnetic moments of baryons affect their relativistic propagation in constant\nelectric fields, electric polarizabilities cannot be determined without\nknowledge of magnetic moments. This is analogous to the experimental situation,\nfor which determination of polarizabilities from the Compton amplitude requires\nsubtraction of Born terms. With the background field method, we devise\ncombinations of nucleon correlation functions in constant electric fields that\nisolate magnetic moments and electric polarizabilities. Using an ensemble of\nanisotropic gauge configurations with dynamical clover fermions, we demonstrate\nhow both observables can be determined from lattice QCD simulations in\nbackground electric fields. We obtain results for the neutron and proton,\nhowever, our study is currently limited to electrically neutral sea quarks. The\nvalue we extract for the nucleon isovector magnetic moment is comparable to\nthose obtained from measuring lattice three-point functions at similar pion\nmasses."
    },
    {
        "anchor": "Application of Quadrature Methods for Re-Weighting in Lattice QCD: Re-weighting is a useful tool that has been employed in Lattice QCD in\ndifferent contexts including, tuning the strange quark mass, approaching the\nlight quark mass regime, and simulating electromagnetic fields on top of QCD\ngauge configurations. In case of re-weighting the sea quark mass, the\nre-weighting factor is given by the ratio of the determinants of two Dirac\noperators $D_a$ and $D_b$. A popular approach for computing this ratio is to\nuse a pseudofermion representation of the determinant of the composite operator\n$\\Omega=D_a(D_b^\\dagger D_b)^{-1} D_a^\\dagger$. Here, we study using quadrature\nmethods together with noise vectors to compute the ratio of determinants. We\nshow that, with quadrature methods each determinant can be computed separately\nusing the operators $\\Omega_a=D_a^\\dagger D_a$ and $\\Omega_b=D_b^\\dagger D_b$.\nWe also discuss using bootstrap re-sampling to remove the bias from the\ndeterminant estimator.",
        "positive": "Lattice study of continuity and finite-temperature transition in\n  two-dimensional SU(N) x SU(N) Principal Chiral Model: We present first-principle lattice study of the two-dimensional SU(N) x SU(N)\nPrincipal Chiral Model (PCM) on the cylinder R x S1 with variable\ncompactification length L0 of S1 and with both periodic and ZN-symmetric\ntwisted boundary conditions. For both boundary conditions our numerical results\ncan be interpreted as signatures of a weak crossover or phase transition\nbetween the regimes of small and large L0. In particular, at small L0\nthermodynamic quantities exhibit nontrivial dependence on L0, and the static\ncorrelation length exhibits a weak enhancement at some \"critical\" value of L0.\nWe also observe important differences between the two boundary conditions,\nwhich indicate that the transition scenario is more likely in the periodic case\nthan in the twisted one. In particular, the enhancement of correlation length\nfor periodic boundary conditions becomes more pronounced at large N, and\npractically does not depend on N for twisted boundary conditions. Using\nGradient Flow we study non-perturbative content of the theory and find that the\npeaks in the correlation length appear when the length L0 becomes comparable\nwith the typical size of unitons, unstable saddle points of PCM. With twisted\nboundary conditions these saddle points become effectively stable and\none-dimensional in the regime of small N L0, whereas at large N L0 they are\nvery similar to the two-dimensional unitons with periodic boundary conditions.\nIn the context of adiabatic continuity conjecture for PCM with twisted boundary\nconditions, our results suggest that while the effect of the compactification\nis clearly different for different boundary conditions, one still cannot\nexclude the possibility of a weak crossover separating the strong-coupling\nregime at large N L0 and the Dunne-Unsal regime at small N L0 with twisted\nboundary conditions."
    },
    {
        "anchor": "The QCD equation of state with asqtad staggered fermions: We report on our result for the equation of state (EOS) with a Symanzik\nimproved gauge action and the asqtad improved staggered fermion action at\n$N_t=4$ and 6. In our dynamical simulations with 2+1 flavors we use the inexact\nR algorithm and here we estimate the finite step-size systematic error on the\nEOS. Finally we discuss the non-zero chemical potential extension of the EOS\nand give some preliminary results.",
        "positive": "Evidence for fine tuning of fermionic modes in lattice gluodynamics: We consider properties of zero and near-zero fermionic modes in lattice\ngluodynamics. The modes are known to be sensitive to the topology of the\nunderlying gluonic fields in the quantum vacuum state of the gluodynamics. We\nfind evidence that these modes are fine tuned, that is exhibit sensitivity to\nboth physical (one can say, hadronic) scale and to the ultraviolet cutoff.\nNamely, the density of the states is in physical units while the localization\nvolume of the modes tends to zero in physical units with the lattice spacing\ntending to zero. We discuss briefly possible theoretical implications and also\ninclude some general, review-type remarks."
    },
    {
        "anchor": "Flavor physics with $\u039b_b$ baryons: At the LHC, bottom baryons are being produced in unprecedented quantities,\nwhich opens up a new field for flavor physics. For example, the decay\n$\\Lambda_b \\to p \\mu^- \\bar{\\nu}$ can be used to obtain a novel determination\nof the CKM matrix element $|V_{ub}|$, and the decay $\\Lambda_b \\to \\Lambda\n\\mu^+ \\mu^-$ probes the weak interactions at the loop level. The first lattice\ncalculations of the relevant $\\Lambda_b \\to p$ and $\\Lambda_b \\to \\Lambda$ form\nfactors have recently been performed using domain-wall light quarks and static\n$b$ quarks. To further reduce the theoretical uncertainty, one has to go beyond\nthe static approximation. Here I present new calculations of $\\Lambda_b \\to p$,\n$\\Lambda_b \\to \\Lambda$, and $\\Lambda_b \\to \\Lambda_c$ form factors using a\nrelativistic heavy-quark action.",
        "positive": "Light Hadron Masses in QCD with Valence Wilson Quarks at beta=6.25 from\n  a Parallel PC Cluster: We present results for $\\pi$, $\\rho$ and proton and $\\Delta$ masses from our\nrecently built Pentium cluster. The previous results for quenched Wilson\nfermions by MILC and GF11 collaborations are compared at $\\beta=6/g^2$=5.7 and\n5.85 with the same parameters on the $8^3\\times32$ lattice. New data are shown\nat $\\beta$=6.25 on the $12^3\\times36$ and $16^3\\times32$ lattices. Such a\nlarger $\\beta$ value is useful for extrapolating the lattice results to the\ncontinuum limit. The smearing technique is systematically investigated and\nshown to greatly improve the spectrum data."
    },
    {
        "anchor": "Abelian color cycle and abelian color flux dualization methods for\n  non-abelian lattice field theories: In this thesis we present the application of the \\textit{abelian color cycle}\n(ACC) and the \\textit{abelian color flux} (ACF) methods to several models: the\nSU(2) principal chiral model, the SU(2) gauge theory with staggered fermions\nand QCD with staggered fermions. The key step of our approaches consists in\ndecomposing the action of the model one is considering into its minimal units.\nFor gauge theories those minimal terms are complex numbers, which we refer to\nas abelian color cycles, while for fermions the action is decomposed into\nGrassmann bilinears, which we called abelian color fluxes. As a result of these\ndecompositions the actions are sums of commuting terms, and thus one can\nproceed with the dualization of the theory as in the abelian case, by\nfactorizing and expanding the Boltzmann weight. The expansion indices,\nso-called dual variables, become the new degrees of freedom for the description\nof the system once the conventional fields are integrated out. The integration\nover the conventional fields results into weight factors and constraints. The\nconstraints implement the symmetries of the theory in the dual form and imply\nthat the dual configurations which contribute to the long range physics are\nworldsheets for the gauge degrees of freedom and worldlines for matter fields.\nOn the other hand, the weight factors allow one to organize the dual partition\nfunction into a strong coupling series of which all terms are known in closed\nform. Moreover, the form of the dependence on the chemical potential allows one\nto identify the net-particle number as the total net temporal winding number of\nthe worldlines in the dual representation.",
        "positive": "2d quantum gravity with discrete edge lengths: An approximation of the Standard Regge Calculus (SRC) was proposed by the\n$Z_2$-Regge Model ($Z_2$RM). There the edge lengths of the simplicial complexes\nare restricted to only two possible values, both always compatible with the\ntriangle inequalities. To examine the effect of discrete edge lengths, we\ndefine two models to describe the transition from the $Z_2$RM to the SRC. These\nmodels allow to choose the number of possible link lengths to be $n =\n{4,8,16,32,64,...}$ and differ mainly in the scaling of the quadratic link\nlengths. The first extension, the $X^1_n$-Model, keeps the edge lengths limited\nand still behaves rather similar to the \"spin-like\" $Z_2$RM. The vanishing\ncritical cosmological constant is reproduced by the second extension, the\n$X^C_n$-Model, which allows for increasing edge lengths. In addition the area\nexpectation values are consistent with the scaling relation of the SRC."
    },
    {
        "anchor": "Semileptonic $D \\rightarrow \u03c0\\ell \u03bd$, $D \\rightarrow K \\ell \u03bd$\n  and $D_s \\rightarrow K \\ell \u03bd$ decays with 2+1f domain wall fermions: We present the status of our project to calculate $D \\to \\pi \\ell \\nu$, $D\n\\to K \\ell \\nu$ and $D_s \\to K \\ell \\nu$ semileptonic form factors using domain\nwall fermions for both heavy and light quarks. Our computations are performed\nusing RBC/UKQCD's set of 2+1 flavour domain wall fermion and Iwasaki gauge\nfield ensembles. We plan to calculate three-point functions covering the full,\nphysically allowed kinematic range. Given that the signal decays faster than\nthe noise, unambiguously and reliably extracting the ground state is critical\nfor success. We include an analysis of operator diagonalisation within several\npossible $2 \\times 2$ operator bases and find an admixture of gauged fixed wall\nand $\\mathbb{Z} \\left( 2 \\right)$ wall sources to be acceptable at both zero\nand non-zero momentum. Initial results for semileptonic form factors are\npresented for first ensembles.",
        "positive": "$\u03c7$SF near the electroweak scale: We employ the chirally rotated Schr\\\"odinger functional ($\\chi$SF) to study\ntwo-point fermion bilinear correlation functions used in the determination of\n$Z_{A,V,S,P,T}$ on a series of well-tuned ensembles. The gauge configurations,\nwhich span renormalisation scales from 4 to 70~GeV, are generated with $N_{\\rm\nf}=3$ massless flavors and Schr\\\"odinger Functional (SF) boundary conditions.\nValence quarks are computed with $\\chi$SF boundary conditions. We show\npreliminary results on the tuning of the $\\chi$SF Symanzik coefficient $z_f$\nand the scaling of the axial current normalization $Z_{\\rm A}$. Moreover we\ncarry out a detailed comparison with the expectations from one-loop\nperturbation theory. Finally we outline how automatically\n$\\mathrm{O}(a)$-improved $B_{\\rm K}$ matrix elements, including BSM\ncontributions, can be computed in a $\\chi$SF renormalization scheme."
    },
    {
        "anchor": "Performance of the Cray T3D and Emerging Architectures on Canopy QCD\n  Applications: The Cray T3D, an MIMD system with NUMA shared memory capabilities and in\nprinciple very low communications latency, can support the Canopy framework for\ngrid-oriented applications. CANOPY has been ported to the T3D, with the intent\nof making it available to a spectrum of users. The performance of the T3D\nrunning Canopy has been benchmarked on five QCD applications extensively run on\nACPMAPS at Fermilab, requiring a variety of data access patterns. The net\nperformance and scaling behavior reveals an efficiency relative to peak Gflops\nalmost identical to that achieved on ACPMAPS. Detailed studies of the major\nfactors impacting performance are presented. Generalizations applying this\nanalysis to the newly emerging crop of commercial systems reveal where their\nlimitations will lie. On these applications, efficiencies of above 25\\% are not\nto be expected; eliminating overheads due to Canopy will improve matters, but\nby less than a factor of two.",
        "positive": "Beyond the Standard Model corrections to $K^0-\\bar{K}^0$ mixing: We calculate the B-parameters for operators arising in theories of new\nphysics beyond the standard model (BSM) using HYP-smeared improved staggered\nfermions on the MILC asqtad lattices with N_f = 2+1 flavors. We use three\ndifferent lattice spacings (a ~ 0.045, 0.06 and 0.09 fm) at a fixed ratio of\nlight to strange quarks, m_l/m_s = 1/5, to obtain the continuum results.\nOperator matching is done using perturbative matching at one-loop order, and\nresults are run to 2 or 3 GeV using two-loop running in the MS-bar scheme. For\nthe chiral and continuum extrapolations, we use SU(2) staggered chiral\nperturbation theory. We present preliminary results with only statistical\nerrors."
    },
    {
        "anchor": "Weyl fermions on the lattice and the non-abelian gauge anomaly: Starting from the Ginsparg-Wilson relation, a general construction of chiral\ngauge theories on the lattice is described. Local and global anomalies are\neasily discussed in this framework and a closed expression for the effective\naction can be obtained. Particular attention is paid to the non-abelian gauge\nanomaly, which is shown to be related to a local topological field on the\nlattice representing the Chern character in 4+2 dimensions.",
        "positive": "Percolation and Deconfinement in SU(2) Gauge Theory: We show that deconfinement in SU(2) gauge theory can be described by the\npercolation of site-bond clusters of like-sign Polyakov loops. In particular,\nwe find that in 2+1 dimensions the percolation variables coincide with those of\nthe 2-dimensional Ising model."
    },
    {
        "anchor": "Baryon Density Correlations in the Quark Plasma, MIMD Lattice\n  Calculation: As part of an ongoing effort to characterize the high temperature phase of\nQCD, we measure the quark baryon density in the vicinity of a fixed test quark\nand compare it with similar measurements at low temperature and at the\ncrossover temperature. Such an observable has also been studied by the Vienna\ngroup. We find an extremely weak correlation at high temperature, suggesting\nthat small color singlet clusters are unimportant in the thermal ensemble. We\nalso find that at T = 0.75 T_c the induced quark number shows a surprisingly\nlarge component attributable to baryonic screening. A simulation of a simple\nflux tube model produces results that suggest a plausible scenario: As the\ncrossover temperature is approached from below, baryonic states proliferate.\nAbove the crossover temperature the mean size of color singlet clusters grows\nexplosively, resulting in an effective electrostatic deconfinement.",
        "positive": "Solutions of the Ginsparg-Wilson relation and improved domain wall\n  fermions: We discuss a number of lattice fermion actions solving the Ginsparg-Wilson\nrelation. We also consider short ranged approximate solutions. In particular,\nwe are interested in reducing the lattice artifacts, while avoiding (or\nsuppressing) additive mass renormalization. In this context, we also arrive at\na formulation of improved domain wall fermions."
    },
    {
        "anchor": "Pseudoscalar-meson--octet-baryon coupling constants in two-flavor\n  lattice QCD: We evaluate the $\\pi N!N$, $\\pi\\Sigma\\Sigma$, $\\pi\\Lambda\\Sigma$, $K\\Lambda\nN$ and $K \\Sigma N $ coupling constants and the corresponding monopole masses\nin lattice QCD with two flavors of dynamical quarks. The parameters\nrepresenting the SU(3)-flavor symmetry are computed at the point where the\nthree quark flavors are degenerate at the physical $s$-quark mass. In\nparticular, we obtain $\\alpha\\equiv F/(F+D)=0.395(6)$. The quark-mass\ndependences of the coupling constants are obtained by changing the $u$- and the\n$d$-quark masses. We find that the SU(3)-flavor parameters have weak quark-mass\ndependence and thus the SU(3)-flavor symmetry is broken by only a few percent\nat each quark-mass point we consider.",
        "positive": "Optimisation of complex integration contours at higher order: We continue our study of contour deformation as a practical tool for dealing\nwith the sign problem using the $d$-dimensional Bose gas with non-zero chemical\npotential as a toy model. We derive explicit expressions for contours up to the\nsecond order with respect to a natural small parameter and generalise these\ncontours to an ansatz for which the evaluation of the Jacobian is fast\n($O(1)$). We examine the behaviour of the various proposed contours as a\nfunction of space-time dimensionality, the chemical potential, and lattice size\nand geometry and use the mean phase factor as a measure of the severity of the\nsign problem. In turns out that this method leads to a substantial reduction of\nthe sign problem and that it becomes more efficient as space-time\ndimensionality is increased. Correlations among contributions to\n$\\operatorname{Im}\\langle S \\rangle$ play a key role in determining the mean\nphase factor and we examine these correlations in detail."
    },
    {
        "anchor": "Topology in 2D CP**(N-1) models on the lattice: a critical comparison of\n  different cooling techniques: Two-dimensional CP**(N-1) models are used to compare the behavior of\ndifferent cooling techniques on the lattice. Cooling is one of the most\nfrequently used tools to study on the lattice the topological properties of the\nvacuum of a field theory. We show that different cooling methods behave in an\nequivalent way. To see this we apply the cooling methods on classical\ninstantonic configurations and on configurations of the thermal equilibrium\nensemble. We also calculate the topological susceptibility by using the cooling\ntechnique.",
        "positive": "Twisted-mass reweighting for O(a) improved Wilson fermions: We test the reweighting of the quark determinant of O(a) improved Wilson\nfermions in the domain-decomposed hybrid Monte-Carlo algorithm. Specifically,\nwe implement a reweighting in a twisted-mass parameter proposed by Palombi and\nL\\\"uscher in $N_{\\rm f}=2$ QCD. We find that at equal acceptance rate, the\nalgorithm is significantly more stable on a $32\\times64^3$ lattice upon\nswitching on the reweighting parameter. At the same time, the reweighting\nfactor does not fluctuate strongly and hence is under control. At equal\nstatistics, the uncertainty on the pion correlator is comparable to the case of\nthe standard, unreweighted algorithm."
    },
    {
        "anchor": "Meson masses and decay constants at large $N$: Meson masses and decay constants in the large $N$ limit of SU($N$) gauge\ntheory are determined using the twisted Eguchi-Kawai reduced model. To this\nend, we make use of a recently defined smearing method valid on the one-point\nlattice. This procedure, in combination with a variational analysis, allows to\nobtain reliable values for these quantities.",
        "positive": "Non-perturbative renormalization of four-quark operators and B_K with\n  Schroedinger functional scheme in quenched domain-wall QCD: We present non-perturbative renormalization factors for $\\Delta S=2$\nfour-quark operators in quenched domain-wall QCD using the Schroedinger\nfunctional method. Non-perturbative renormalization factor for $B_K$ is\nevaluated at hadronic scale. Combined with the non-perturbative RG running\nobtained by the Alpha collaboration, our result yields renormalization factor\nwhich converts lattice bare $B_K$ to the renormalization group invariant one.\nWe apply the renormalization factor to bare $B_K$ previously obtained by the\nCP-PACS collaboration with the quenched domain-wall QCD(DWQCD). We compare our\nresult with previous ones obtained by perturbative renormalization factors,\ndifferent renormalization schemes or different quark actions. We also show that\nchiral symmetry breaking effects in the renormalization factor are numerically\nsmall."
    },
    {
        "anchor": "Quenched Charmed Meson Spectra using Tadpole Improved Quark Action on\n  Anisotropic Lattices: Charmed meson charmonium spectra are studied with improved quark actions on\nanisotropic lattices. We measured the pseudo-scalar and vector meson dispersion\nrelations for 4 lowest lattice momentum modes with quark mass values ranging\nfrom the strange quark to charm quark with 3 different values of gauge coupling\n$\\beta$ and 4 different values of bare speed of light $\\nu$. With the bare\nspeed of light parameter $\\nu$ tuned in a mass-dependent way, we study the mass\nspectra of $D$, $D_s$, $\\eta_c$,\n  $D^{\\ast}$, $D_s^{\\ast}$ and $J/\\psi$ mesons.\n  The results extrapolated to the continuum limit are compared with the\nexperiment and qualitative agreement is found.",
        "positive": "Scaling test of fermion actions in the Schwinger model: We discuss the scaling behaviour of different fermion actions in dynamical\nsimulations of the 2-dimensional massive Schwinger model. We have chosen\nWilson, hypercube, twisted mass and overlap fermion actions. As physical\nobservables, the pion mass and the scalar condensate are computed for the above\nmentioned actions at a number of coupling values and fermion masses. We also\ndiscuss possibilities to simulate overlap fermions dynamically avoiding\nproblems with low-lying eigenvalues of the overlap kernel."
    },
    {
        "anchor": "Ab-initio Determination of Light Hadron Masses: More than 99% of the mass of the visible universe is made up of protons and\nneutrons. Both particles are much heavier than their quark and gluon\nconstituents, and the Standard Model of particle physics should explain this\ndifference. We present a full ab-initio calculation of the masses of protons,\nneutrons and other light hadrons, using lattice quantum chromodynamics. Pion\nmasses down to 190 mega electronvolts are used to extrapolate to the physical\npoint with lattice sizes of approximately four times the inverse pion mass.\nThree lattice spacings are used for a continuum extrapolation. Our results\ncompletely agree with experimental observations and represent a quantitative\nconfirmation of this aspect of the Standard Model with fully controlled\nuncertainties.",
        "positive": "Exploring Lee-Yang and Fisher Zeros in the 2D Ising Model through\n  Multi-Point Pad\u00e9 Approximants: We present a numerical calculation of the Lee-Yang and Fisher zeros of the 2D\nIsing model using multi-point Pad\\'{e} approximants. We perform simulations for\nthe 2D Ising model with ferromagnetic couplings both in the absence and in the\npresence of a magnetic field using a cluster spin-flip algorithm. We show that\nit is possible to extract genuine signature of Lee Yang and Fisher zeros of the\ntheory through the poles of magnetization and specific heat, using multi-point\nPad\\'{e} method. We extract the poles of magnetization using Pad\\'{e}\napproximants and compare their scaling with known results. We verify the circle\ntheorem associated to the well known behaviour of Lee Yang zeros. We present\nour finite volume scaling analysis of the zeros done at $T=T_c$ for a few\nlattice sizes, extracting to a very good precision the (combination of)\ncritical exponents $\\beta \\delta$. The computation at the critical temperature\nis performed after the latter has been determined via the study of Fisher\nzeros, thus extracting both $\\beta_c$ and the critical exponent $\\nu$. Results\nalready exist for extracting the critical exponents for the Ising model in 2\nand 3 dimensions making use of Fisher and Lee Yang zeros. In this work,\nmulti-point Pad\\'{e} is shown to be competitive with this respect and thus a\npowerful tool to study phase transitions."
    },
    {
        "anchor": "Challenges in Hadronic Form Factor Calculations: There is an extensive history of form factor calculations on the lattice,\nprimarily with ground states for both initial and final states. However, there\nhave never been any radially excited transition form factor calculations.\nFurthermore, the lattice faces difficulty in extracting signal from noise at\nlarge transfer momenta ($Q^2$). These measurements could give important\ntheoretical input to experiments, such as those of JLab's 12 GeV program and\nstudies of deformation of the nucleon. In this work, I will present a simple\ntechnique to resolve both of these difficulties and present results from\nanisotropic configurations showing improved signals for excited-state\nquantities. It should also be possible to apply this technique to isotropic\nlattices for calculating large-$Q^2$ form factors.",
        "positive": "Charmonium dissociation temperatures in lattice QCD with a finite volume\n  technique: Dissociation temperatures of J/\\psi, \\psi', and \\chi_c states play key roles\nin the sequential J/\\psi suppression scenario for high energy heavy ion\ncollisions. We report on a study of charmonium dissociation temperatures in\nquenched lattice QCD. On anisotropic lattices, we first subtract the effects of\nthe constant mode in finite temperature meson correlators, which have lead to\nunphysical results in previous studies. We then extract ground and first exited\nstate masses by diagonalizing correlation functions among different source and\nsink operators. To distinguish bound states from scattering states, we first\ncompare the charmonium mass spectra under different spatial boundary\nconditions, and examine the shape and the volume-dependence of their\nBethe-Salpeter wave functions. From these studies, we found so far no sign of\nscattering states up to about 2.3T_c."
    },
    {
        "anchor": "Revealing Topological Structure in the SU(2) Vacuum: In this paper we derive a simple parametrization of the cycling method\ndeveloped by us in our earlier work. The new method, called renormalization\ngroup (RG) mapping, consists of a series of carefully tuned APE-smearing steps.\nWe study the relation between cycling and RG mapping. We also investigate in\ndetail how smooth instantons and instanton-anti-instanton pairs behave under\nthe RG mapping transformation. We use the RG mapping technique to study the\ntopological susceptibility and instanton size distribution of SU(2) gauge\ntheory. We find scaling in both quantities in a wide range of coupling values.\nOur result for the topological susceptibility, chi^1/4=220(6) MeV, agrees with\nour earlier results.",
        "positive": "Fractionally charged Wilson loops as a probe of $\u03b8$-dependence in\n  $CP^{N-1}$ sigma models: Instantons vs. large N: The behavior of Wilson loops with fractional charge is used to study the\n$\\theta$-dependence of the free energy density $\\epsilon(\\theta)$ for the\n$CP^1$, $CP^5$, and $CP^9$ sigma models in two spacetime dimensions. The\nfunction $\\epsilon(\\theta)$ is extracted from the area law for a Wilson loop of\ncharge $q=\\theta/2\\pi$. For $CP^1$, $\\epsilon(\\theta)$ is smooth in the region\n$\\theta\\approx\\pi$ and well-described by a dilute instanton gas throughout the\nrange $0<\\theta<2\\pi$. For $CP^5$ and $CP^9$ the energy exhibits a clear cusp\nand evidence for discrete, degenerate vacua at $\\theta = \\pi$, as expected from\nlarge $N$ arguments. For $CP^9$ the $\\theta$-dependence is in good quantitative\nagreement with the leading order large $N$ prediction\n$\\epsilon(\\theta)={1/2}\\chi_t\\theta^2$ throughout the range $0<\\theta<\\pi$."
    },
    {
        "anchor": "Medium-heavy nuclei from nucleon-nucleon interactions in lattice QCD: On the basis of the Brueckner-Hartree-Fock method with the nucleon-nucleon\nforces obtained from lattice QCD simulations, the properties of the\nmedium-heavy doubly-magic nuclei such as 16^O and 40^Ca are investigated. We\nfound that those nuclei are bound for the pseudo-scalar meson mass M_PS ~ 470\nMeV. The mass number dependence of the binding energies, single-particle\nspectra and density distributions are qualitatively consistent with those\nexpected from empirical data at the physical point, although these hypothetical\nnuclei at heavy quark mass have smaller binding energies than the real nuclei.",
        "positive": "Particle density probability distribution function and center symmetry\n  breaking in finite density lattice gauge theories: We study the nature of the phase transition at high temperature and high\ndensity in lattice gauge theories by focusing on the probability distribution\nfunction, which represents the probability that a certain density will be\nrealized in a heat bath. The probability distribution function is obtained by\nconstructing a canonical partition function by fixing the number of particles\nfrom the grand partition function. However, if the Z3 center symmetry, which is\nimportant for understanding the finite temperature phase transition of SU(3)\nlattice gauge theory, is maintained on a finite lattice, the probability\ndistribution function is always zero, except when the number of particles is a\nmultiple of 3. For U(1) gauge theory, this problem is more extreme. The\nprobability distribution becomes zero when the particle number is not zero. In\nthis study, we find a solution to this problem and propose a method of avoiding\nthe sign problem, which is an important problem at finite density, using the\ncenter symmetry. This problem is essentially the same as the problem that the\nexpectation value of the Polyakov loop is always zero when calculating with\nfinite volume. In the case of U(1) lattice gauge theory with heavy fermions,\nnumerical simulations are actually performed, and we demonstrate that the\nprobability distribution function at a finite density can be calculated by the\nmethod proposed in this study."
    },
    {
        "anchor": "Worldlines and worldsheets for non-abelian lattice field theories:\n  Abelian color fluxes and Abelian color cycles: We discuss recent developments for exact reformulations of lattice field\ntheories in terms of worldlines and worldsheets. In particular we focus on a\nstrategy which is applicable also to non-abelian theories: traces and\nmatrix/vector products are written as explicit sums over color indices and a\ndual variable is introduced for each individual term. These dual variables\ncorrespond to fluxes in both, space-time and color for matter fields (Abelian\ncolor fluxes), or to fluxes in color space around space-time plaquettes for\ngauge fields (Abelian color cycles). Subsequently all original degrees of\nfreedom, i.e., matter fields and gauge links, can be integrated out.\nIntegrating over complex phases of matter fields gives rise to constraints that\nenforce conservation of matter flux on all sites. Integrating out phases of\ngauge fields enforces vanishing combined flux of matter- and gauge degrees of\nfreedom. The constraints give rise to a system of worldlines and worldsheets.\nIntegrating over the factors that are not phases (e.g., radial degrees of\nfreedom or contributions from the Haar measure) generates additional weight\nfactors that together with the constraints implement the full symmetry of the\nconventional formulation, now in the language of worldlines and worldsheets. We\ndiscuss the Abelian color flux and Abelian color cycle strategies for three\nexamples: the SU(2) principal chiral model with chemical potential coupled to\ntwo of the Noether charges, SU(2) lattice gauge theory coupled to staggered\nfermions, as well as full lattice QCD with staggered fermions. For the\nprincipal chiral model we present some simulation results that illustrate\nproperties of the worldline dynamics at finite chemical potentials.",
        "positive": "Electric form factors of the octet baryons from lattice QCD and chiral\n  extrapolation: We apply a formalism inspired by heavy baryon chiral perturbation theory with\nfinite-range regularization to dynamical $2+1-$flavor CSSM/QCDSF/UKQCD\nCollaboration lattice QCD simulation results for the electric form factors of\nthe octet baryons. The electric form factor of each octet baryon is\nextrapolated to the physical pseudoscalar masses, after finite-volume\ncorrections have been applied, at six fixed values of $Q^2$ in the range\n0.2-1.3 GeV$^2$. The extrapolated lattice results accurately reproduce the\nexperimental form factors of the nucleon at the physical point, indicating that\nomitted disconnected quark loop contributions are small. Furthermore, using the\nresults of a recent lattice study of the magnetic form factors, we determine\nthe ratio $\\mu_p G^p_E/G^p_M$. This quantity decreases with $Q^2$ in a way\nqualitatively consistent with recent experimental results."
    },
    {
        "anchor": "Baryon magnetic moments in the background field method: We present a calculation of the magnetic moments for the baryon octet and\ndecuplet using the background-field method and standard Wilson gauge and\nfermion actions in the quenched approximation of lattice QCD. Progressively\nsmaller static magnetic fields are introduced on a $24^4$ lattice at beta=6.0\nand the pion mass is probed down to about 500 MeV. Magnetic moments are\nextracted from the linear response of the masses to the background field.",
        "positive": "A comparison of the cut-off effects for Twisted Mass, Overlap and Creutz\n  fermions at tree-level of Perturbation Theory: In this paper we investigate the cutoff effects at tree-level of perturbation\ntheory for three different lattice regularizations of fermions -- maximally\ntwisted mass Wilson, overlap and Creutz fermions. We show that all three kinds\nof fermions exhibit the expected $O(a^2)$ scaling behaviour in the lattice\nspacing. Moreover, the size of these cutoff effects for the considered\nquantities i.e. the pseudoscalar correlation function $C_{PS}$, the mass\n$m_{PS}$ and the decay constant $f_{PS}$ is comparable for all of them."
    },
    {
        "anchor": "Search for Lambda^2/p^2 corrections to the QCD running coupling: We investigate the occurrence of power terms $(Lambda^2/p^2$ in the running\nQCD coupling by analysing non-perturbative measurements of $\\alpha_s(p)$ at\nquite low momenta obtained from the lattice three-gluon vertex. Our study\nprovides some evidence for such a contribution. The phenomenological\nimplications of such a presence are reviewed.",
        "positive": "Simple Hadronic Matrix Elements with Wilson Valence Quarks and Dynamical\n  Staggered Fermions at ${\\bf 6/g^2=5.6}$: We have measured some simple matrix elements for pseudoscalar and vector\nmesons made of Wilson valence quarks and staggered sea quarks at $\\beta=5.6$ at\nsea quark masses $am_q=0.01$ and 0.025. Our measurements include the decay\nconstants of pseudoscalars (including $f_D$), the wave function at the origin\n(or decay constant) of vector mesons, and the calculation of quark masses from\ncurrent algebra. The effects of sea quarks on the simulations are small. We\nmake comparisons to quenched simulations at similar values of the lattice\nspacing ($1/a \\simeq 2$ GeV)."
    },
    {
        "anchor": "UV-filtered overlap fermions: We discuss the kernel spectrum, locality properties and the axial-vector\nrenormalization constant of UV-filtered overlap fermions. We find that\nUV-filtered overlap fermions have a better conditioned kernel, better locality\nand an axial-vector renormalization constant closer to 1 than their unfiltered\ncounterparts, even if the shift parameter $\\rho$ is simply set to 1.",
        "positive": "Monte Carlo studies of antiferromagnetic spin models in three dimensions: We study several antiferromagnetic formulations of the O(3) spin model in\nthree dimensions by means of Monte Carlo simulations. We discuss about the\nvacua properties and analyze the phase transitions. Using Finite Size Scaling\nanalysis we conclude that all phase transitions found are of first order"
    },
    {
        "anchor": "The chiral phase transition for QCD with sextet quarks: QCD with 2 massless colour-sextet quarks is studied as a model of Walking\nTechnicolor. We simulate lattice QCD with 2 light color-sextet staggered quarks\nat finite temperature, and use the dependence of the coupling at the chiral\ntransition on the temporal extent, $N_t$, of the lattice in lattice units to\nstudy the running of the bare lattice coupling with lattice spacing. Our goal\nis to determine whether this theory is QCD-like and `walks', or if it is\nconformal. If it is QCD-like, the coupling at the chiral transition should tend\nto zero as $N_t \\rightarrow \\infty$ in a manner controlled by asymptotic\nfreedom, i.e. by the perturbative $\\beta$-function. On the other hand, if this\ntheory is conformal, this coupling will approach a non-zero limit in the $N_t\n\\rightarrow \\infty$ limit. We are extending our simulations on an $N_t=8$\nlattice to determine the position of the chiral transition with greater\naccuracy, and are performing simulations on an $N_t=12$ lattice.",
        "positive": "Finite Volume Effects and Quenched Chiral Logarithms: We have measured the valence pion mass and the valence chiral condensate on\nlattice configurations generated with and without dynamical fermions. We find\nthat our data and that of others is well represented by a linear relationship\nbetween $m_{\\pi}^2$ and the valence quark mass, with a non-zero intercept. For\nour data, we relate the intercept to finite volume effects visible in the\nvalence chiral condensate. We see no evidence for the singular behavior\nexpected from quenched chiral logarithms."
    },
    {
        "anchor": "Matrix product states for gauge field theories: The matrix product state formalism is used to simulate Hamiltonian lattice\ngauge theories. To this end, we define matrix product state manifolds which are\nmanifestly gauge invariant. As an application, we study 1+1 dimensional one\nflavour quantum electrodynamics, also known as the massive Schwinger model, and\nare able to determine very accurately the ground state properties and\nelementary one-particle excitations in the continuum limit. In particular, a\nnovel particle excitation in the form of a heavy vector boson is uncovered,\ncompatible with the strong coupling expansion in the continuum. We also study\nnon-equilibrium dynamics by simulating the real-time evolution of the system\ninduced by a quench in the form of a uniform background electric field.",
        "positive": "Quasi-PDFs from Twisted mass fermions at the physical point: We present results for the flavor non-singlet u-d parton distribution\nfunctions within the nucleon using the quasi-PDF approach. The lattice\ncalculation is performed by employing the twisted mass formulation and two\ngauge ensembles, having $N_f = 2$ and $N_f = 2 + 1 + 1$ dynamical fermions with\nmasses tuned to their physical value. For the $N_f = 2$ physical point\nensemble, the unpolarized, helicity and transversity distributions are computed\nfor three values of the nucleon momentum, namely [6, 8, 10]$\\pi/L$\ncorresponding to [0.83,1.11,1.38] GeV. Upon renormalization, we find that, as\nthe nucleon momentum increases, the lattice results approach the\nphenomenological distributions resulting from analyses of deep inelastic\nscattering data, opening a promising path for a direct evaluation of parton\ndistributions from the QCD Lagrangian. For the $N_f = 2 + 1 + 1$ physical point\nensemble, we present preliminary results for the unpolarized distribution\nextracted from a nucleon boosted by $8\\pi/L$ or 0.97 GeV."
    },
    {
        "anchor": "Preliminary results of $\u0394I=1/2$ and $3/2$, $K$ to $\u03c0\u03c0$ Decay\n  Amplitudes from Lattice QCD: We report a direct lattice calculation of the $K$ to $\\pi\\pi$ decay matrix\nelements for both $\\Delta I=1/2$ and $3/2$ channels on 2+1 flavor, domain wall\nfermion, $16^3\\times32$ lattices with zero $\\pi\\pi$ relative momentum and\n$m_\\pi=420$ MeV. All $K^0$ to $\\pi\\pi$ contractions are carefully listed and\ncalculated. The decay into the isospin zero $\\pi\\pi$ final state, which\nreceives contributions from the disconnected graphs, is very difficult to\ncalculate, but a clear signal in the similar disconnected $\\pi\\pi$ correlator\ncan be seen. Preliminary results, some with large errors, will be presented for\nthe various contributions to the renormalized weak matrix elements $A_0$ and\n$A_2$. We obtain Re$(A_0)$ with $25%$ error in the case of zero momentum on\nshell decay, and find a factor of 6 enhancement for the $\\Delta I=1/2$ rule in\nthe $420$ MeV pion system.",
        "positive": "The QCD phase diagram for external magnetic fields: The effect of an external (electro)magnetic field on the finite temperature\ntransition of QCD is studied. We generate configurations at various values of\nthe quantized magnetic flux with $N_f=2+1$ flavors of stout smeared staggered\nquarks, with physical masses. Thermodynamic observables including the chiral\ncondensate and susceptibility, and the strange quark number susceptibility are\nmeasured as functions of the field strength. We perform the renormalization of\nthe studied observables and extrapolate the results to the continuum limit\nusing $N_t=6,8$ and 10 lattices. We also check for finite volume effects using\nvarious lattice volumes. We find from all of our observables that the\ntransition temperature $T_c$ significantly decreases with increasing magnetic\nfield. This is in conflict with various model calculations that predict an\nincreasing $T_c(B)$. From a finite volume scaling analysis we find that the\nanalytic crossover that is present at B=0 persists up to our largest magnetic\nfields $eB \\approx 1 \\textmd{GeV}^2$, and that the transition strength\nincreases mildly up to this $eB\\approx1 \\textmd{GeV}^2$."
    },
    {
        "anchor": "Quantum gravity and spin systems: A new method for nonperturbative investigations of quantum gravity is\npresented in which the simplicial path integral is approximated by the\npartition function of a spin system. This facilitates analytical and numerical\ncomputations considerably. In two dimensions equivalence to an Ising model with\nternary couplings is recovered. First simulations in four dimensions indicate\nstrong similarities to the phase structure of original Regge theory.",
        "positive": "Approximation Theory for Matrices: We review the theory of optimal polynomial and rational Chebyshev\napproximations, and Zolotarev's formula for the sign function over the range\n(\\epsilon \\leq |z| \\leq1). We explain how rational approximations can be\napplied to large sparse matrices efficiently by making use of partial fraction\nexpansions and multi-shift Krylov space solvers."
    },
    {
        "anchor": "Study of the hadronic contributions to the running of the QED coupling\n  and the weak mixing angle: The electromagnetic coupling receives significant contributions to its\nrunning from non-perturbative QCD effects. We present an update of a lattice\nQCD study of the Adler function and of its application to the determination of\nthe running of the QED coupling. We perform a high-statistics computation with\ntwo flavours of O$(a)$ improved Wilson fermions in a large range of momentum\ntransfer $Q^2$. The running of the electromagnetic coupling, including\ncontributions from $u$, $d$, $s$ and $c$ valence quarks, is compared to\nphenomenological determinations at intermediate $Q^2$ values. An extension of\nthis study to the determination of the hadronic contributions to the running of\nthe weak mixing angle is also described.",
        "positive": "The dual of non-Abelian Lattice Gauge Theory: Non-Abelian Lattice Gauge Theory in Euclidean space-time of dimension d>=2\nwhose gauge group is any compact Lie group is related to a Spin Foam Model by\nan exact strong-weak duality transformation. The group degrees of freedom are\nintegrated out and replaced by combinatorial expressions involving irreducible\nrepresentations and intertwiners of the gauge group. This transformation is\navailable for the partition function, for the expectation value of observables\n(spin networks), and for the correlator of centre monopoles which is a ratio of\npartition functions in the original model and an ordinary expectation value in\nthe dual formulation."
    },
    {
        "anchor": "Form factor for Dalitz decays from $J/\u03c8$ to light pseudoscalars: We calculate the form factor $M(q^2)$ for the Dalitz decay $J/\\psi\\to\n\\gamma^*(q^2)\\eta_{(N_f=1)}$ with $\\eta_{(N_f)}$ being the SU($N_f$) flavor\nsinglet pseudoscalar meson. The difference among the partial widths\n$\\Gamma(J/\\psi\\to \\gamma \\eta_{(N_f)})$ at different $N_f$ can be attributed in\npart to the $\\mathbf{U}_A(1)$ anomaly that induces a $N_f$ scaling. $M(q^2)$'s\nin $N_f=1,2$ are both well described by the single pole model\n$M(q^2)=M(0)/(1-q^2/\\Lambda^2)$. Combined with the known experimental results\nof the Dalitz decays $J/\\psi\\to Pe^+e^-$, the pseudoscalar mass $m_P$\ndependence of the pole parameter $\\Lambda$ is approximated by\n$\\Lambda(m_P^2)=\\Lambda_1(1-m_P^2/\\Lambda_2^2)$ with\n$\\Lambda_1=2.64(4)~\\mathrm{GeV}$ and $\\Lambda_2=2.97(33)~\\mathrm{GeV}$. These\nresults provide inputs for future theoretical and experimental studies on the\nDalitz decays $J/\\psi\\to Pe^+e^-$.",
        "positive": "Monopoles, confinement and deconfinement in lattice compact QED in\n  (2+1)D with external fields: Finite temperature compact electrodynamics in (2+1) dimensions is studied in\nthe presence of external electromagnetic fields. The deconfinement temperature\nis found to be insensitive to the external fields. This result corroborates our\nobservation that external fields create additional small--size magnetic dipoles\nfrom the vacuum which do not spoil the confining properties of the model at low\ntemperature. However, the Polyakov loop is not an order parameter of\nconfinement. It can vanish in deconfinement in the presence of external field.\nThis does not mean the restoration of confinement for certain external field\nfluxes. As a next step in the study of (2+1)D QED, the influence of monopoles\non the photon propagator is studied. First results are presented showing this\nconnection in the confining phase (without external field)."
    },
    {
        "anchor": "Flux tubes and string breaking in three dimensional SU(2) Yang-Mills\n  theory: We consider the three dimensional SU(2) Yang-Mills theory with adjoint static\ncolor sources, studying by lattice simulations how the shape of the flux tube\nchanges when increasing the distance between them. The disappearance of the\nflux tube at string breaking is quite abrupt, but precursors of this phenomenon\nare present already when the separation between the sources is smaller than its\ncritical value, a fact that influences also some details of the static\npotential.",
        "positive": "Universality and the approach to the continuum limit in lattice gauge\n  theory: The universality of the continuum limit and the applicability of renormalized\nperturbation theory are tested in the SU(2) lattice gauge theory by computing\ntwo different non-perturbatively defined running couplings over a large range\nof energies. The lattice data (which were generated on the powerful APE\ncomputers at Rome II and DESY) are extrapolated to the continuum limit by\nsimulating sequences of lattices with decreasing spacings. Our results confirm\nthe expected universality at all energies to a precision of a few percent. We\nfind, however, that perturbation theory must be used with care when matching\ndifferent renormalized couplings at high energies."
    },
    {
        "anchor": "The static quark potential in three flavor QCD: We study the effects of dynamical quarks on the static quark potential at\ndistances shorter than those where string breaking is expected. Quenched\ncalculations and calculations with three flavors of dynamical quarks are done\non sets of lattices with the lattice spacings matched within about one percent.\nThe effect of the sea quarks on the shape of the potential is clearly visible.\nWe investigate the consequences of these effects in a very crude model, namely\nsolving Schroedinger's equation in the resulting potential.",
        "positive": "Naive Lattice Fermion without Doublers: We discuss the naive lattice fermion without the issue of doublers. A local\nlattice massless fermion action with chiral symmetry and hermiticity cannot\navoid the doubling problem from the Nielsen-Ninomiya theorem. Here we adopt the\nforward finite-difference deforming the $\\gamma_5$-hermiticity but preserving\nthe continuum chiral-symmetry. The lattice momentum is not hermitian without\nthe continuum limit now. We demonstrate that there is no doubling issue from an\nexact solution. The propagator only has one pole in the first-order accuracy.\nTherefore, it is hard to know the avoiding due to the non-hermiticity. For the\nsecond-order, the lattice propagator has two poles as before. This case also\ndoes not suffer from the doubling problem. Hence separating the forward\nderivative from the backward one evades the doublers under the field theory\nlimit. Simultaneously, it is equivalent to breaking the hermiticity. In the\nend, we discuss the topological charge and also demonstrate the numerical\nimplementation of the Hybrid Monte Carlo."
    },
    {
        "anchor": "Lattice QCD Spectroscopy with an Improved Wilson Fermion Action: We study the hadronic spectrum in quenched lattice QCD using an improved\nWilson fermion action (Hamber-Wu(1983),Eguchi-Kawamoto(1984)) at $\\beta= 5.7$\nand $\\beta =6.0$. We find a systematic reduction of the finite spacing effects\ncompared to the results obtained by using the standard Wilson action.",
        "positive": "Large-N phase transitions in the spectrum of products of complex\n  matrices: It is shown that the simplest multiplicative random complex matrix model\ngeneralizes the large-N phase structure found in the unitary case: A\nperturbative regime is joined to a nonperturbative regime at a point of\nnonanalyticity."
    },
    {
        "anchor": "Continuum limit of hyperon vector coupling $f_1(0)$ from 2+1 flavor\n  domain wall QCD: We determine the hyperon vector couplings $f_1(0)$ for $\\Sigma^{-}\\rightarrow\nnl^-\\bar{\\nu_l}$ and $\\Xi^0\\rightarrow\\Sigma^{+}l^-\\bar{\\nu_l}$ semileptonic\ndecays in the continuum limit with (2+1)-flavors of dynamical domain-wall\nfermions, using the Iwasaki gauge action at two different lattice spacings of\n$a$=0.114(2) and 0.086(2) fm. A theoretical estimation of flavor SU(3)-breaking\neffect on the vector coupling is required to extract $V_{us}$ from the\nexperimental rate of hyperon beta decays. We obtain the vector couplings\n$f_1(0)$ for $\\Sigma\\rightarrow N$ and $\\Xi\\rightarrow \\Sigma$ beta-decays with\nan accuracy of less than one percent. We then find that lattice results of\n$f_1(0)$ combined with the best estimate of $|V_{us}|$ with imposing\nCabibbo-Kobayashi-Maskawa (CKM) unitarity are slightly deviated from the\nexperimental result of $|V_{us}f_1(0)|$ for the $\\Sigma\\rightarrow N$\nbeta-decay. This discrepancy can be attributed to an assumption made in the\nexperimental analysis on $|V_{us}f_1(0)|$, where the induced second-class form\nfactor $g_2$ is set to be zero regardless of broken SU(3) symmetry. We report\non this matter and then estimate the possible value of $g_2(0)$, which is\nevaluated from the experimental decay rate with our lattice result of $f_1(0)$\nunder the first-row CKM-unitarity condition.",
        "positive": "Physical matrix elements for Delta I = 3/2 channel K to pi pi decays: K to pi pi matrix elements of the electroweak operator Q_(27,1)^Delta I=3/2\nare calculated on the RBC/UKQCD 32^3 x 64, L_s=16 lattices, using 2+1 dynamical\nflavors and domain wall fermions, with an inverse lattice spacing of\na^(-1)=2.42(4) GeV. Data is interpolated or extrapolated to energy conserving\nkinematics and a preliminary calculation of the experimental parameter |A_2| is\nperformed."
    },
    {
        "anchor": "Status of next-generation $\u039b_b \\to p, \u039b, \u039b_c$\n  form-factor calculations: I present preliminary results of next-generation lattice-QCD calculations of\nthe $\\Lambda_b \\to p$, $\\Lambda_b \\to \\Lambda$, and $\\Lambda_b \\to \\Lambda_c$\nform factors based on RBC/UKQCD gauge-field ensembles with 2+1 flavors of\ndomain-wall fermions. Compared to the work published in 2015 and 2016, the new\ncalculations include three additional ensembles (one with 139 MeV pion mass,\none with 0.073 fm lattice spacing, and one with another volume) and were\nperformed with a more accurate tuning of the charm and bottom anisotropic\nclover action parameters.",
        "positive": "Two-loop evaluation of large Wilson loops with overlap fermions: the\n  b-quark mass shift, and the quark-antiquark potential: We compute, to two loops in pertubation theory, the fermionic contribution to\nrectangular RxT Wilson loops, for different values of R and T.\n  We use the overlap fermionic action. We also employ the clover action, for\ncomparison with existing results in the literature.\n  In the limit R, T -> Infinity our results lead to the shift in the b-quark\nmass. We also evaluate the perturbative static potential as T -> Infinity."
    },
    {
        "anchor": "A test of a new simulation algorithm for dynamical quarks: Some results of test runs on a $6^3\\times 12$ lattice with Wilson quarks and\ngauge group SU(2) for a previously proposed fermion algorithm by A. Slavnov are\npresented.",
        "positive": "Screening of the topological charge in a correlated instanton vacuum: Screening of the topological charge due to he fermion-induced interactions is\nan important phenomenon, closely related with the resolution of the strong CP\nand U(1) problems. We study the mechanism of such screening in a 'correlated\ninstanton vacuum', as opposed to the 'random' one. Both scalar and pseudoscalar\ngluonic correlators are analyzed by means of an observable that minimizes\nfinite size effects. Screening of the topological charge is established. This\nallows us to calculate the $\\eta'$ mass without having to invert the Dirac\noperator. We suggest that this method might be used in lattice QCD calculations\nas well. Our results for the screening of the topological charge are in\nagreement with the chiral Ward identities, and the scalar gluonic correlator\nsatisfies a low energy theorem first derived by Novikov et al.\n\\cite{Novikov-etal}. We also propose to evaluate the topological susceptibility\nin the Witten-Veneziano formula not in an infinite box in an world $without$\nfermions but in an infinitesimal box in a world $with$ fermions."
    },
    {
        "anchor": "The ``Spin'' Structure of the Nucleon - a lattice investigation: We will discuss here an indirect lattice evaluation of the baryon axial\nsinglet current matrix element. This quantity may be related to the fraction of\nnucleon spin carried by the quarks. The appropriate structure function has\nrecently been measured (EMC experiment). As in this experiment, we find that\nthe quarks do not appear to carry a large component of the nucleon spin.",
        "positive": "On strongly coupled quenched QED4, again: chiral symmetry breaking,\n  Goldstone mechanism and the nature of the continuum limit: We explore the possibility of a trivial continuum limit of strongly coupled\nquenched QED4 by contrasting our results with a Nambu--Jona Lasinio equation of\nstate. The data does not compare favorably with such scenario. We study in\ndetail the interplay of chiral symmetry breaking with the Goldstone mechanism,\nand clarify some puzzling features of past results."
    },
    {
        "anchor": "Prospects for large N gauge theories on the lattice: I will review recent progress on addressing large N gauge theories on the\nlattice. The focus will be put on the use of large N volume independence as an\neffective tool to compute non-perturbative dynamics at, otherwise unreachable,\nlarge number of colours. A selection of results will be presented and future\nprospects and challenges for the study of large N QCD and various extensions\nwill be discussed.",
        "positive": "Study of constant mode in charmonium correlators at finite temperature: Recent studies on the spectral function of charmonium in lattice QCD suggest\nsurvival of $J/\\psi$ state in the deconfinement phase till relatively high\ntemperature. Based on the studies, different scenarios of $J/\\psi$ suppression\nare discussed to understand experimental results in the Heavy Ion Collision\nexperiments. The scenarios require the information on the dissociation\ntemperatures of $\\chi_c$ and $\\psi'$ as well as that of $J/\\psi$. In order to\ninvestigate these states in finite temperature lattice QCD, we have to consider\nan effect of a characteristic constant mode in the correlators. As a result of\nthe study on the constant mode, we find that most drastic change in charmonium\ncorrelators for $\\chi_c$ states just above the deconfinement transition are\ncaused by the constant mode. It may indicate the survival of $\\chi_c$ states\nafter the deconfinement transition until, at least, $1.4T_c$."
    },
    {
        "anchor": "Models of Walking Technicolor on the Lattice: We study QCD with 2 colour-sextet quarks as a walking-Technicolor candidate.\nAs such it provides a description of the Higgs sector of the standard model, in\nwhich the Higgs field is replaced by the Goldstone `pions' of this QCD-like\ntheory, and the Higgs itself is the $\\sigma$. Such a theory will need to be\nextended if it is to also give masses to the quarks and leptons. What we are\nattempting to determine is whether it is indeed QCD-like and hence walking, or\nif it has an infrared fixed point making it a conformal field theory. We do\nthis by simulating its lattice version at finite temperature and observing the\nrunning of the bare (lattice) coupling at the chiral transition, as the lattice\nspacing is varied, and comparing this running with that predicted by 2-loop\nperturbation theory. Our results on lattices with temporal extents ($N_t$) up\nto 12 indicate that the coupling runs, but not as fast as asymptotic freedom\npredicts. We discuss our program for studying the zero-temperature\nphenomenology of this theory.",
        "positive": "Tensor Charge of the Nucleon on the Lattice: Tensor charge of the nucleon, which will be measured in Drell-Yan processes\nin polarized proton-proton collisions at RHIC, are studied in quenched lattice\nQCD simulation. On the 16$^3\\times$ 20 lattice with $\\beta=5.7$, connected\nparts of the tensor charge are determined with small statistical error, while\nthe disconnected parts are found to be small with relatively large error bars.\nFlavor-singlet tensor charge ($\\delta \\Sigma = \\delta u + \\delta d + \\delta s$)\nis not suppressed as opposed to the flavor singlet axial charge ($\\Delta \\Sigma\n= \\Delta u + \\Delta d + \\Delta s$)."
    },
    {
        "anchor": "Quark Mass Dependence of Heavy Quark Diffusion Coefficient from Lattice\n  QCD: We present the first study of the quark mass dependence of the heavy quark\nmomentum and spatial diffusion coefficients using lattice QCD with light\ndynamical quarks corresponding to a pion mass of 320 MeV. We find that, for the\ntemperature range 195 MeV $<T<$ 293 MeV, the spatial diffusion coefficients of\nthe charm and bottom quarks are smaller than those obtained in phenomenological\nmodels that describe the $p_T$ spectra and elliptic flow of open heavy flavor\nhadrons.",
        "positive": "Light Scalar Meson and Decay Constant in SU(3) Gauge Theory with Eight\n  Dynamical Flavors: The SU(3) gauge theory with $N_f=8$ nearly massless Dirac fermions has long\nbeen of theoretical and phenomenological interest due to the near-conformality\narising from its proximity to the conformal window. One particularly\ninteresting feature is the emergence of a relatively light, stable\nflavor-singlet scalar meson $\\sigma$ $(J^{PC}=0^{++})$ in contrast to the\n$N_f=2$ theory QCD. In this work, we study the finite-volume dependence of the\n$\\sigma$ meson correlation function computed in lattice gauge theory and\ndetermine the $\\sigma$ meson mass and decay constant extrapolated to the\ninfinite-volume limit. We also determine the infinite volume mass and decay\nconstant of the flavor-nonsinglet scalar meson $a_0$."
    },
    {
        "anchor": "O(a) improvement of lattice QCD with two flavors of Wilson quarks: We consider O(a) improvement for two flavor lattice QCD. The improvement term\nin the action is computed non-perturbatively for a large range of the bare\ncoupling. The position of the critical line and higher order lattice artifacts\nremaining after improvement are estimated. We also discuss the behavior of the\nHMC algorithm in our simulations.",
        "positive": "$I=1$ and $I=2$ $\u03c0-\u03c0$ scattering phase shifts from $N_{\\mathrm{f}} =\n  2+1$ lattice QCD: The $I=1$ $p$-wave and $I=2$ $s$-wave elastic $\\pi$-$\\pi$ scattering\namplitudes are calculated from a first-principles lattice QCD simulation using\na single ensemble of gauge field configurations with $N_{\\mathrm{f}} = 2+1$\ndynamical flavors of anisotropic clover-improved Wilson fermions. This ensemble\nhas a large spatial volume $V=(3.7\\mathrm{fm})^3$, pion mass $m_{\\pi} =\n230\\mathrm{MeV}$, and spatial lattice spacing $a_s = 0.11\\mathrm{fm}$.\nCalculation of the necessary temporal correlation matrices is efficiently\nperformed using the stochastic LapH method, while the large volume enables an\nimproved energy resolution compared to previous work. For this single ensemble\nwe obtain $m_{\\rho}/m_{\\pi} = 3.350(24)$, $g_{\\rho\\pi\\pi} = 5.99(26)$, and a\nclear signal for the $I=2$ $s$-wave. The success of the stochastic LapH method\nin this proof-of-principle large-volume calculation paves the way for\nquantitative study of the lattice spacing effects and quark mass dependence of\nscattering amplitudes using state-of-the-art ensembles."
    },
    {
        "anchor": "Phase transitions and non-analyticities in large N gauge theories: We investigate numerically various phase transitions and non-analyticities at\nlarge N using both twisted Eguchi-Kawai space-time reduction and the standard\nWilson theory.",
        "positive": "First lattice study of low-energy charmonium-hadron interaction: We study the scattering lengths of charmonia (J/psi and eta_c) with light\nhadrons (pi, rho and N) by the quenched lattice QCD simulations on 24x24x24x48,\n32x32x32x48 and 48x48x48x48 lattices with the lattice spacing a = 0.068 fm. The\nscattering length is extracted by using the Luscher's phase-shift formula\ntogether with the measurement of the energy shift Delta E of two hadrons on the\nlattice. We find that there exist attractive interactions in all channels,\nJ/psi(eta_c)-pi, J/psi(eta_c)-rho and J/psi(eta_c)-N: The s-wave J/psi-pi\n(eta_c-pi) scattering length is determined as 0.0119+-0.0039 fm (0.0113+-0.0035\nfm) and the corresponding elastic cross section at the threshold becomes\n0.018+0.013-0.010 mb (0.016+0.011-0.008 mb). Also, the J/psi-N (eta_c-N)\nspin-averaged scattering length is 0.71+-0.48 fm (0.70+-0.66 fm), which is at\nleast an order of magnitude larger than the charmonium-pion scattering length.\nThe volume dependence of the energy shifts is also investigated to check the\nexpected 1/L^3 behavior of Delta E at a large spatial size L."
    },
    {
        "anchor": "Normalizing flows for lattice gauge theory in arbitrary space-time\n  dimension: Applications of normalizing flows to the sampling of field configurations in\nlattice gauge theory have so far been explored almost exclusively in two\nspace-time dimensions. We report new algorithmic developments of\ngauge-equivariant flow architectures facilitating the generalization to\nhigher-dimensional lattice geometries. Specifically, we discuss masked\nautoregressive transformations with tractable and unbiased Jacobian\ndeterminants, a key ingredient for scalable and asymptotically exact flow-based\nsampling algorithms. For concreteness, results from a proof-of-principle\napplication to SU(3) lattice gauge theory in four space-time dimensions are\nreported.",
        "positive": "Scaling and ChPT Description of Pions from N_f=2 twisted mass QCD: We study light-quark observables by means of dynamical lattice QCD\nsimulations using two flavours of twisted mass fermions at maximal twist. We\nemploy chiral perturbation theory to describe our data for the pion mass and\ndecay constant. In this way, we extract precise determinations for the\nlow-energy constants of the effective theory as well as for the light-quark\nmass and the chiral condensate."
    },
    {
        "anchor": "Progress report on computing the disconnected QCD and the QCD plus QED\n  hadronic contributions to the muon's anomalous magnetic moment: We report progress on calculating the contribution to the anomalous magnetic\nmoment of the muon from the disconnected hadronic diagrams with light and\nstrange quarks and the valence QED contribution to the connected diagrams. The\nlattice QCD calculations use the highly-improved staggered quark (HISQ)\nformulation. The gauge configurations were generated by the MILC Collaboration\nwith four flavors of HISQ sea quarks with physical sea-quark masses.",
        "positive": "Lattice QCD Calculations of the Sigma Commutator: As a direct source of information on chiral symmetry breaking within QCD, the\nsigma commutator is of considerable importance. With recent advances in the\ncalculation of hadron masses within full QCD it is of interest to see whether\nthe sigma commutator can be calculated directly from the dependence of the\nnucleon mass on the input quark mass. We show that provided the correct chiral\nbehaviour of QCD is respected in the extrapolation to realistic quark masses\none can indeed obtain a fairly reliable determination of the sigma commutator\nusing present lattice data. Within two-flavour, dynamical-fermion QCD the value\nobtained lies in the range 45 to 55 MeV."
    },
    {
        "anchor": "Exploring the structure of the quenched QCD vacuum with overlap fermions: Overlap fermions have an exact chiral symmetry on the lattice and are thus an\nappropriate tool for investigating the chiral and topological structure of the\nQCD vacuum. We study various chiral and topological aspects of quenched gauge\nfield configurations. This includes the localization and chiral properties of\nthe eigenmodes, the local structure of the ultraviolet filtered field strength\ntensor, as well as the structure of topological charge fluctuations. We\nconclude that the vacuum has a multifractal structure.",
        "positive": "The Running Coupling from SU(3) Lattice Gauge Theory: {}From an accurate determination of the inter-quark potential, one can study\nthe running coupling constant for a range of $R$-values and hence estimate the\nscale $\\Lambda_{\\msbar} $. Detailed results are presented for $SU(3)$ pure\ngauge theory."
    },
    {
        "anchor": "Determination of $\\overline{m}_b/\\overline{m}_c$ and $\\overline{m}_b$\n  from $n_f=4$ lattice QCD$+$QED: We extend HPQCD's earlier $n_f=4$ lattice-QCD analysis of the ratio of\n$\\overline{\\mathrm{MSB}}$ masses of the $b$ and $c$ quark to include results\nfrom finer lattices (down to 0.03fm) and a new calculation of QED contributions\nto the mass ratio. We find that\n$\\overline{m}_b(\\mu)/\\overline{m}_c(\\mu)=4.586(12)$ at renormalization scale\n$\\mu=3$\\,GeV. This result is nonperturbative. Combining it with HPQCD's recent\nlattice QCD$+$QED determination of $\\overline{m}_c(3\\mathrm{GeV})$ gives a new\nvalue for the $b$-quark mass: $\\overline{m}_b(3\\mathrm{GeV}) = 4.513(26)$GeV.\nThe $b$-mass corresponds to $\\overline{m}_b(\\overline{m}_b, n_f=5) =\n4.202(21)$GeV. These results are the first based on simulations that include\nQED.",
        "positive": "Critical behaviour of the 1D q-state Potts model with long-range\n  interactions: The critical behaviour of the one-dimensional q-state Potts model with\nlong-range interactions decaying with distance r as $r^{-(1+\\sigma)}$ has been\nstudied in the wide range of parameters $0 < \\sigma \\le 1$ and $\\frac{1}{16}\n\\le q \\le 64$. A transfer matrix has been constructed for a truncated range of\ninteractions for integer and continuous q, and finite range scaling has been\napplied. Results for the phase diagram and the correlation length critical\nexponent are presented."
    },
    {
        "anchor": "Flux tubes at finite temperature: The chromoelectric field generated by a static quark-antiquark pair, with its\npeculiar tube-like shape, can be nicely described, at zero temperature, within\nthe dual superconductor scenario for the QCD confining vacuum. In this work we\ninvestigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory,\nthe fate of chromoelectric flux tubes across the deconfinement transition. We\nfind that, as the temperature is increased towards and above the deconfinement\ntemperature $T_c$, the amplitude of the field inside the flux tube gets\nsmaller, while the shape of the flux tube does not vary appreciably across\ndeconfinement. This scenario with flux-tube \"evaporation\" above $T_c$ has no\ncorrespondence in ordinary (type-II) superconductivity, where instead the\ntransition to the phase with normal conductivity is characterized by a\ndivergent fattening of flux tubes as the transition temperature is approached\nfrom below. We present also some evidence about the existence of flux-tube\nstructures in the magnetic sector of the theory in the deconfined phase.",
        "positive": "Partial restoration of chiral symmetry in the color flux tube: Using the quark eigenmodes computed on the lattice with the overlap-Dirac\noperator, we investigate the spatial distribution of the chiral condensate\naround static color sources corresponding to quark-antiquark and three-quark\nsystems. A flux structure of chromo fields appears in the presence of such\ncolor charges. The magnitude of the chiral condensate is reduced inside the\ncolor flux, which implies partial restoration of chiral symmetry inside\nhadrons. Taking a static baryon source in a periodic box as a toy model of\nnuclear matter, we estimate the magnitude of the chiral symmetry restoration as\na function of baryon matter density."
    },
    {
        "anchor": "M_b and f_B from non-perturbatively renormalized HQET with Nf=2 light\n  quarks: We present an updated analysis of the non-perturbatively renormalized b-quark\nmass and B meson decay constant based on CLS lattices with two dynamical\nnon-perturbatively improved Wilson quarks. This update incorporates additional\nlight quark masses and lattice spacings in large physical volume to improve\nchiral extrapolations and to reach the continuum limit. We use Heavy Quark\nEffective Theory (HQET) including 1/m_b terms with non-perturbative\ncoefficients based on the matching of QCD and HQET developed by the ALPHA\ncollaboration during the past years.",
        "positive": "Deconfinement Transition in Large N Lattice Gauge Theory: We study analytically the phase diagram of the pure $SU(N)$ lattice gauge\ntheory at finite temperature, and we attempt to estimate the critical\ndeconfinement temperature. We apply large $N$ techniques to the Wilson and to\nthe Heat Kernel action, and we study the resulting models both in the strong\ncoupling and in the weak coupling limits. Using the Heat Kernel action, we\nestablish an interesting connection between the Douglas-Kazakov phase\ntransition of two-dimensional QCD and the deconfining transition in $d$\ndimensions. The analytic results obtained for the critical temperature compare\nwell with Montecarlo simulations of the full theory in $(2+1)$ and in $(3+1)$\ndimensions."
    },
    {
        "anchor": "Magnetic moments of light nuclei from lattice quantum chromodynamics: We present the results of lattice QCD calculations of the magnetic moments of\nthe lightest nuclei, the deuteron, the triton and ${}^3$He, along with those of\nthe neutron and proton. These calculations, performed at quark masses\ncorresponding to $m_\\pi \\sim 800$ MeV, reveal that the structure of these\nnuclei at unphysically heavy quark masses closely resembles that at the\nphysical quark masses. In particular, we find that the magnetic moment of\n${}^3$He differs only slightly from that of a free neutron, as is the case in\nnature, indicating that the shell-model configuration of two spin-paired\nprotons and a valence neutron captures its dominant structure. Similarly a\nshell-model-like moment is found for the triton, $\\mu_{{}^3{\\rm H}} \\sim\n\\mu_p$. The deuteron magnetic moment is found to be equal to the nucleon\nisoscalar moment within the uncertainties of the calculations.",
        "positive": "Lattice Hadron Structure: Applications within and beyond QCD: Study of the hadronic matrix elements can provide not only tests of the QCD\nsector of the Standard Model (in comparing with existing experiments) but also\nreliable low-energy hadronic quantities applicable to a wide range of\nbeyond-the-Standard Model scenarios where experiments or theoretical\ncalculations are limited or difficult. On the QCD side, progress has been made\nin the notoriously difficult problem of addressing gluonic structure inside the\nnucleon, reaching higher-$Q^2$ region of the form factors, and providing a\ncomplete picture of the proton spin. However, even further study and\nimprovement of systematic uncertainties are needed. There are also proposed\ncalculations of higher-order operators in the neutron electric dipole moment\nLagrangian, which would be useful when combined with effective theory to probe\nBSM. Lattice isovector tensor and scalar charges can be combined with upcoming\nneutron beta-decay measurements of the Fierz interference term and neutrino\nasymmetry parameter to probe new interactions in the effective theory,\nrevealing the scale of potential new TeV particles. Finally, I revisit the\nsystematic uncertainties in recent calculations of $g_A$ and review prospects\nfor future calculations."
    },
    {
        "anchor": "Solving the PCAC puzzle for nucleon axial and pseudoscalar form factors: It has been observed in multiple lattice determinations of isovector axial\nand pseudoscalar nucleon form factors, that, despite the fact that the partial\nconservation of the axialvector current is fulfilled on the level of\ncorrelation functions, the corresponding relation for form factors (sometimes\ncalled the generalized Goldberger-Treiman relation in the literature) is broken\nrather badly. In this work we trace this difference back to excited state\ncontributions and propose a new projection method that resolves this problem.\nWe demonstrate the efficacy of this method by computing the axial and\npseudoscalar form factors as well as related quantities on ensembles with two\nflavors of improved Wilson fermions using pion masses down to 150 MeV. To this\nend, we perform the $z$-expansion with analytically enforced asymptotic\nbehaviour and extrapolate to the physical point.",
        "positive": "Searching for the critical endpoint in QCD with two quark flavors: I present a method which can be used to locate the expected critical endpoint\nof the phase diagram of QCD with two light quark flavors. I illustrate the\nideas on a suitable Random Matrix Model and show preliminary results in QCD"
    },
    {
        "anchor": "First Evidence of $N_f$-Dependence in the QCD Interquark Potential: We present a lattice calculation of the interquark potential between static\nquarks in a ``full'' QCD simulation with 2 flavours of dynamical Wilson-quarks\nat three intermediate sea-quark masses. We work at $\\beta = 5.6$ on lattice\nsize of $16^3 \\times 32$ with 100 configurations per sea-quark mass. We compare\nthe full QCD potential with its quenched counterpart at equal lattice spacing,\n$a^{-1} \\simeq 2.0$ GeV, which is at the onset of the quenched scaling regime.\nWe find that the full QCD potential lies consistently below that of quenched\nQCD. We see no evidence for string-breaking effects on these lattice volumes,\n$V \\simeq (1.5\\,\\,{\\rm fm})^3$.",
        "positive": "A numerical and theoretical study of multilevel performance for\n  two-point correlator calculations: An investigation of the performance of the multilevel algorithm in the\napproach to criticality has been undertaken using the Ising model, performing\nsimulations across a range of temperatures. Numerical results show that the\nperformance of multilevel in this system deteriorates as the correlation length\nis increased with respect to the lattice size. The statistical error of the\nlongest correlator in the system is reduced in a multilevel setup when the\ncorrelation length is less than one-tenth of the lattice size, while for longer\ncorrelation lengths multilevel performs more poorly than a computer-time\nequivalent single level algorithm. A theoretical model of this performance\nscaling is outlined, and shows remarkable accuracy when compared to numerical\nresults. This theoretical model may be applied to other systems with more\ncomplex spectra to predict if multilevel techniques are likely to result in\nimproved statistics."
    },
    {
        "anchor": "First Lattice QCD determination of semileptonic decays of\n  charmed-strange baryons $\u039e_c$: While the standard model is the most successfully theory to describe all\ninteractions and constituents in elementary particle physics, it has been\nconstantly examined for over four decades. Weak decays of charm quarks can\nmeasure the coupling strength of quarks in different families and serve as an\nideal probe for CP violation. As the lowest charm-strange baryons with three\ndifferent flavors, $\\Xi_c$ baryons (made of $csu$ or $csd$) have been\nextensively studied in experiments at the large hadron collider and in\nelectron-positron collision. However the lack of reliable knowledge in theory\nbecomes the unavoidable obstacle in the way. In this work, we use the\nstate-of-the-art Lattice QCD techniques, and generate 2+1 clover fermion\nensembles with two lattice spacings, $a=(0.108{\\rm fm},0.080{\\rm fm})$. We then\npresent the first {\\it ab-initio} lattice QCD determination of form factors\ngoverning $\\Xi_{c}\\to \\Xi \\ell^+\\nu_{\\ell}$, analogous with the notable\n$\\beta$-decay of nuclei. Our theoretical results for decay widths are\nconsistent with and about two times more precise than the latest measurements\nby ALICE and Belle collaborations. Together with experimental measurements, we\nindependently determine the quark-mixing matrix element $|V_{cs}|$, which is\nfound in good agreement with other determinations.",
        "positive": "Anomaly cancellation condition in lattice effective electroweak theory: The anomaly cancellation is at the basis of the perturbative consistence of\nthe Standard Model and it provides a partial explanation of charge\nquantization. We consider an effective Electroweak theory on a lattice, with a\nquartic interaction describing the weak forces and an interaction with the e.m.\nfield. We prove the validity of the anomaly cancellation at a non perturbative\nlevel and with a finite lattice cut-off, even if the lattice breaks some\nimportant symmetries, on which perturbative arguments for the cancellation are\nbased. The method of the proof has analogies with the one adopted for\nestablishing universality in transport of quantum materials."
    },
    {
        "anchor": "The Landau gauge gluon and ghost propagators in 4D SU(3) gluodynamics in\n  large lattice volumes: We present recent results of the Landau gauge gluon and ghost propagators in\nSU(3) pure gauge theory at Wilson \\beta=5.7 for lattice sizes up to 80^4\ncorresponding to physical volumes up to (13.2 fm)^4. In particular, we focus on\nfinite-volume and Gribov copy effects. We employ a gauge fixing method that\ncombines a simulated annealing algorithm with finalizing overrelaxation. We\nfind the gluon propagator for the largest volumes and at q^2 ~ 0.01 GeV^2 to\nbecome flat. Although not excluded by our data, there is still no clear\nindication of a gluon propagator tending towards zero in the zero-momentum\nlimit. New data for the ghost propagator are reported, too.",
        "positive": "Polyakov loops and SU(2) staggered Dirac spectra: We consider the spectrum of the staggered Dirac operator with SU(2) gauge\nfields. Our study is motivated by the fact that the antiunitary symmetries of\nthis operator are different from those of the SU(2) continuum Dirac operator.\nIn this contribution, we investigate in some detail staggered eigenvalue\nspectra close to the free limit. Numerical experiments in the quenched\napproximation and at very large $\\beta$-values show that the eigenvalues occur\nin clusters consisting of eight eigenvalues each. We can predict the locations\nof these clusters for a given configuration very accurately by an analytical\nformula involving Polyakov loops and boundary conditions. The spacing\ndistribution of the eigenvalues within the clusters agrees with the chiral\nsymplectic ensemble of random matrix theory, in agreement with theoretical\nexpectations, whereas the spacing distribution between the clusters tends\ntowards Poisson behavior."
    },
    {
        "anchor": "Recent progress in finite temperature lattice QCD: I review recent progress in the determination of the QCD phase diagram at\nfinite temperature, in investigations of the nature of the transition or\ncrossover from the hadronic phase to the quark-gluon plasma phase and in the\ndetermination of the equation of state. This talk will focus on results at zero\nchemical potential.",
        "positive": "On the Infinite Variance Problem in Fermion Models: Monte Carlo calculations of fermionic systems with continuous auxiliary\nfields frequently suffer from a diverging variance. If a system has the\ninfinite variance problem, one cannot estimate observables reliably even with\nan infinite number of samples. In this paper, we explore a method to deal with\nthis problem based on sampling according to the distribution of a system with\nan extra time-slice. The necessary reweighting factor is computed both\nperturbatively and through a secondary Monte Carlo. We show that the Monte\nCarlo reweigthing coupled to the use of a non-biased estimator of the\nreweigthing factor leads to a method that eliminates the infinite variance\nproblem at a very small extra cost. We compute the double occupancy in the\nHubbard model at half-filling to demonstrate the method and compare the results\nto well established results obtained by other methods."
    },
    {
        "anchor": "Entropy of spatial monopole currents in pure SU(2) QCD at finite\n  temperature: We study properties of space-like monopole trajectories in the Maximal\nAbelian gauge of quenched SU(2) QCD at the finite temperature. We concentrate\non infrared monopole clusters which are responsible for the confinement\nproperties of the theory. We determine numerically the effective action of the\nmonopoles projected onto the three-dimensional time-slice. Then we derive the\nlength distributions of the monopole loops and fix their entropy.",
        "positive": "Point-Split Lattice Operators for B Decays: The matrix element which determines the B meson decay constant can be\nmeasured on the lattice using an effective field theory for heavy quarks.\nVarious discretizations of the heavy-light bilinears which appear in this and\nother B decay matrix elements are possible. The heavy-light bilinear currently\nused for the determination of the B meson decay constant on the lattice suffers\na substantial one-loop renormalization. In this paper, we compute the one-loop\nrenormalizations of the discretizations in which the heavy and light fields in\nthe bilinear are separated by one lattice spacing, and discuss their\napplication. Readers of this paper may also be interested in our paper on the\napplication of Symanzik's improvement program to heavy-light currents (paper\nnumber 9203221 on hep-ph)."
    },
    {
        "anchor": "Introducing Fermionic Link Models: Quantum link models (QLMs) are extensions of Wilson-type lattice gauge\ntheories, and show rich physics beyond the phenomena of conventional Wilson\ngauge theories. Here we explore the physics of $U(1)$ symmetric QLMs, both\nusing a more conventional quantum spin-1/2 representation, as well as a\nfermionic representation. In 2D, we show that both bosonic and fermionic QLMs\ndisplay the same physics. We then explore the models in 3D and find different\nbehavior for the two QLMs. For the bosons, we see evidence for a quantum phase\ntransition from a symmetry broken phase to a potential quantum spin liquid\nphase. For the fermions, we identify not one but two distinct phases in\naddition to a symmetry broken phase. We explore the symmetries of the ground\nstate in the strong coupling limit, which breaks lattice symmetries and examine\nthe spectrum for both models.",
        "positive": "Confined Charged Particles in C-periodic Volumes: Charged particles in an Abelian Coulomb phase are non-local infraparticles\nthat are surrounded by a cloud of soft photons which extends to infinity.\nGauss' law prevents the existence of charged particles in a periodic volume. In\na $C$-periodic volume, which is periodic up to charge conjugation, on the other\nhand, charged particles can exist. This includes vortices in the $3$-d\nXY-model, magnetic monopoles in $4$-d $\\mathrm{U}(1)$ gauge theory, as well as\nprotons and other charged particles in QCD coupled to QED. In four dimensions\nnon-Abelian charges are confined. Hence, in an infinite volume non-Abelian\ninfraparticles cost an infinite amount of energy. However, in a $C$-periodic\nvolume non-Abelian infraparticles (whose energy increases linearly with the box\nsize) can indeed exist. Investigating these states holds the promise of\ndeepening our understanding of confinement."
    },
    {
        "anchor": "Photon production rate from Transverse-Longitudinal ($T-L$) mesonic\n  correlator on the lattice: Thermal photons from the QGP provide important information about the\ninteraction among plasma constituents. The photon production rate from a\nthermally equilibrated system is proportional to the transverse spectral\nfunction $\\rho_T(\\omega=|\\vec k|, \\vec k)$. One can also calculate the photon\nproduction rate from the difference between $\\rho_T(\\omega,\\vec k)$\n(transverse) and $\\rho_L(\\omega,\\vec k)$ (longitudinal) projections, as\n$\\rho_L$ vanishes on the photon point. Because the UV part of $\\rho_T-\\rho_L$\nis suppressed, the corresponding Euclidean correlator receives most of its\ncontribution from the IR part. We calculate the $T\\!-\\!L$ correlator on\n$N_f=2+1$ flavour HISQ configurations with $m_l=m_s/5$ at temperature of about\n$1.15\\,T_{pc}$ (220 MeV). We have used two ans\\\"{a}tze for the spectral\nfunction: 1) A polynomial connected to the UV region consistent with OPE\nexpansion and 2) a hydro-inspired spectral function. We have also applied the\nBackus-Gilbert method to estimate the spectral function. All these different\napproaches are combined to estimate the photon production rate.",
        "positive": "Tensor renormalization group approach to (1+1)-dimensional Hubbard model: We investigate the metal-insulator transition of the (1+1)-dimensional\nHubbard model in the path-integral formalism with the tensor renormalization\ngroup method. The critical chemical potential $\\mu_{\\rm c}$ and the critical\nexponent $\\nu$ are determined from the $\\mu$ dependence of the electron density\nin the thermodynamic limit. Our results for $\\mu_{\\rm c}$ and $\\nu$ show\nconsistency with an exact solution based on the Bethe ansatz. Our encouraging\nresults indicate the applicability of the tensor renormalization group method\nto the analysis of higher-dimensional Hubbard models."
    },
    {
        "anchor": "The flavour and quark mass dependence of thermodynamic quantities in\n  lattice QCD: The dependence of thermodynamic properties of QCD on the number of quark\nflavours is investigated. Lattice results for the equation of state are\npresented for 2, 2+1 and 3 quark flavours. The simulations have been performed\nwith the improved p4-staggered fermion and a Symanzik improved gluon action on\nlattices of size 16^3 x 4",
        "positive": "Speed of sound exceeding the conformal bound in dense 2-color QCD: We review recent works on the Monte Carlo simulations of dense two-color QCD\n(QC$_2$D) by focusing on the phase diagram, the equation of state, and the\nsound velocity at nonzero quark chemical potential. A possible upper bound of\nthe sound velocity is known as the conformal bound, namely, $c_s^2/c^2 \\leq\n1/3$. The sound velocity is below the bound at least in the case of\nfinite-temperature QCD. However, our recent work~\\cite{Iida:2022hyy} shows the\nbreaking of this bound in dense QC$_2$D. This phenomenon was previously unknown\nfrom any lattice calculations. We also discuss recent related works including\nlattice studies on QCD at nonzero isospin chemical potential, some effective\nmodel analyses, and an analysis based on recent neutron star observations.\nThese works also suggest the breaking of the conformal bound."
    },
    {
        "anchor": "Monte Carlo Methods for the Self-Avoiding Walk: This article is a pedagogical review of Monte Carlo methods for the\nself-avoiding walk, with emphasis on the extraordinarily efficient algorithms\ndeveloped over the past decade. Many more details can be found in\nhep-lat/9405016.",
        "positive": "An new order parameter with renormalized Polyakov loops: It is well established that physical quantities like the heavy quark\npotentials get temperature independent at sufficiently short distances. As a\nfirst application of this feature we suggest a new order parameter for the\nconfinement/deconfinement phase transition. Our investigations are based on\nrecent lattice studies."
    },
    {
        "anchor": "The Influence of Instantons on the Quark Propagator: We use over-improved stout-link smearing to investigate the presence and\nnature of instantons on the lattice. We find that smearing can remove\nshort-range effects with little damage to the long-range structure of the gauge\nfield, and that after around 50 sweeps this process is complete. There are more\nsignificant risks for very high levels of smearing beyond 100 sweeps. We are\nthus able to produce gauge configurations dominated by instanton effects. We\nthen calculate the overlap quark propagator on these configurations, and thus\nthe non-perturbative mass function. We find that smeared configurations\nreproduce the majority of dynamical mass generation, and conclude that\ninstantons are primarily responsible for the dynamical generation of mass.",
        "positive": "Lattice gluodynamics at negative g^2: We consider Wilson's SU(N) lattice gauge theory (without fermions) at\nnegative values of beta= 2N/g^2 and for N=2 or 3. We show that in the limit\nbeta -> -infinity, the path integral is dominated by configurations where links\nvariables are set to a nontrivial element of the center on selected non\nintersecting lines. For N=2, these configurations can be characterized by a\nunique gauge invariant set of variables, while for N=3 a multiplicity growing\nwith the volume as the number of configurations of an Ising model is observed.\nIn general, there is a discontinuity in the average plaquette when g^2 changes\nits sign which prevents us from having a convergent series in g^2 for this\nquantity. For N=2, a change of variables relates the gauge invariant\nobservables at positive and negative values of beta. For N=3, we derive an\nidentity relating the observables at beta with those at beta rotated by +-\n2pi/3 in the complex plane and show numerical evidence for a Ising like first\norder phase transition near beta=-22. We discuss the possibility of having\nlines of first order phase transitions ending at a second order phase\ntransition in an extended bare parameter space."
    },
    {
        "anchor": "Scalar-matter-gluon interaction: A full non-perturbative treatment of gauge theories requires to include\nmatter fields on equal footing with the gauge fields. Scalar matter can act as\na role model for generic matter, as many questions, e.g. confinement, can be\nposed without referring to a particular Lorentz structure. Due to their rather\nsimple structure they are also useful to develop methods.\n  One possible way to describe gauge theories beyond perturbation theory is\nbased on correlation functions. After a short discussion of the setup, lattice\ngauge theory is used to analyze the interaction of gluons with quenched\nfundamental and adjoint scalars. Both the two-point and three-point correlation\nfunctions for massive and massless adjoint and fundamental scalars will be\ndetermined, in minimal Landau gauge. The findings are in agreement with the\npossibility that scalars are only slightly affected by the interaction with\ngluons. The results are compared briefly with dynamical, massive scalars,\nshowing no significant changes in the confinement region compared to the\nquenched case.",
        "positive": "Shearing approach to gauge invariant Trotterization: Universal quantum simulations of gauge field theories are exposed to the risk\nof gauge symmetry violations when it is not known how to compile the desired\noperations exactly using the available gate set. In this letter, we show how\ntime evolution can be compiled in an Abelian gauge theory -- if only\napproximately -- without compromising gauge invariance, by graphically\nmotivating a block-diagonalization procedure. When gauge invariant interactions\nare associated with a \"spatial network\" in the space of discrete quantum\nnumbers, it is seen that cyclically shearing the spatial network converts\nsimultaneous updates to many quantum numbers into conditional updates of a\nsingle quantum number: ultimately, this eliminates any need to pass through\n(and acquire overlap onto) unphysical intermediate configurations. Shearing is\nexplicitly applied to gauge-matter and magnetic interactions of lattice QED.\nThe features that make shearing successful at preserving Abelian gauge symmetry\nmay also be found in non-Abelian theories, bringing one closer to gauge\ninvariant simulations of quantum chromodynamics."
    },
    {
        "anchor": "Finite temperature behaviour of glueballs in Lattice Gauge Theories: We propose a new method to compute glueball masses in finite temperature\nLattice Gauge Theories which at low temperature is fully compatible with the\nknown zero temperature results and as the temperature increases leads to a\nglueball spectrum which vanishes at the deconfinement transition. We show that\nthis definition is consistent with the Isgur-Paton model and with the expected\ncontribution of the glueball spectrum to various thermodynamic quantities at\nfinite temperature. We test our proposal with a set of high precision numerical\nsimulations in the 3d gauge Ising model and find a good agreement with our\npredictions.",
        "positive": "Deflation and Flexible SAP-Preconditioning of GMRES in Lattice QCD\n  Simulation: The simulation of lattice QCD on massively parallel computers stimulated the\ndevelopment of scalable algorithms for the solution of sparse linear systems.\nWe tackle the problem of the Wilson-Dirac operator inversion by combining a\nSchwarz alternating procedure (SAP) in multiplicative form with a flexible\nvariant of the GMRES-DR algorithm. We show that restarted GMRES is not able to\nconverge when the system is poorly conditioned. By adding deflation in the form\nof the FGMRES-DR algorithm, an important fraction of the information produced\nby the iterates is kept between successive restarts leading to convergence in\ncases in which FGMRES stagnates."
    },
    {
        "anchor": "The equation of state at high temperatures from lattice QCD: We present results for the equation of state upto previously unreachable,\nhigh temperatures. Since the temperature range is quite large, a comparison\nwith perturbation theory can be done directly.",
        "positive": "Non-perturbative renormalisation of left-left four-fermion operators\n  with Neuberger fermions: We outline a general strategy for the non-perturbative renormalisation of\ncomposite operators in discretisations based on Neuberger fermions, via a\nmatching to results obtained with Wilson-type fermions. As an application, we\nconsider the renormalisation of the four-quark operators entering the Delta S=1\nand Delta S=2 effective Hamiltonians. Our results are an essential ingredient\nfor the determination of the low-energy constants governing non-leptonic kaon\ndecays."
    },
    {
        "anchor": "Four fermion condensates in $SU(2)$ Yang-Mills-Higgs theory on a lattice: We study a model of four reduced staggered fields transforming in the\nbifundamental representation of a $SU(2)\\times SU(2)$ symmetry group where just\none of the SU(2) factors is gauged. This field content and symmetries are\nsimilar to a Higgs-Yukawa model that has been studied recently. The key\nobservation in the latter work is that fermions acquire masses at strong\ncoupling via the formation of a symmetric four fermion condensate in contrast\nto the more usual symmetry breaking bilinear condensate seen in eg. NJL models.\nThe current work attempts to see whether this structure survives when the four\nfermi interactions are replaced by gauge interactions and to explore the\nresulting phase diagram.",
        "positive": "Extracting three-body observables from finite-volume quantities: Scattering and transition amplitudes with three-hadron final states play an\nimportant role in nuclear and particle physics. However, predicting such\nquantities using numerical Lattice QCD is very difficult, in part because of\nthe effects of Euclidean time and finite volume. In this review we highlight\nrecent formal developments that work towards overcoming these issues. We\norganize the presentation into three parts: large volume expansions,\nnon-relativistic nonperturbative analyses, and nonperturbative studies based in\nrelativistic field theory.\n  In the first part we discuss results for ground state energies and matrix\nelements given by expanding in inverse box length, $1/L$. We describe\ncomplications that arise at $\\mathcal O(1/L^6)$ and include a table summarizing\nthe results of different calculations.\n  In the second part we summarize three recent non-relativistic\nnon-perturbative studies and highlight the main conclusions of these works.\nThis includes demonstrating that the three-particle finite-volume spectrum is\ndetermined, up to exponentially suppressed effects, by on-shell amplitudes, as\nwell as recovering a finite-volume quantization condition for scattering a\nstable particle off a two-particle bound state. In this part we also highlight\nrecent work concerning a three-particle bound state in a finite volume.\n  In the third and final part, we review recent work based in non-perturbative\nrelativistic field theory. Here the finite-volume spectrum has been related to\nan intermediate infinite-volume quantity which itself is related via a known\nintegral equation to the relativistic, model-independent three-particle\nscattering amplitude. We motivate the appearance of the intermediate quantity,\nexplain how it is related to the standard amplitude, and discuss prospects for\nusing the result to constrain three-particle observables."
    },
    {
        "anchor": "Masses and Decay Constants of Pseudoscalar Mesons to Two Loops in\n  Two-Flavor Partially Quenched Chiral Perturbation Theory: This paper presents a first study of the masses and decay constants of the\ncharged, or flavor-off-diagonal, pseudoscalar mesons to two loops for two\nflavors of sea-quarks, in Partially Quenched Chiral Perturbation Theory\n(PQ$\\chi$PT). Explicit analytical expressions up to ${\\cal O}(p^6)$ in the\nmomentum expansion are given. The calculations have been performed within the\nsupersymmetric formulation of PQ$\\chi$PT. A numerical analysis is done to\nindicate the size of the corrections.",
        "positive": "Distribution of the k-th smallest Dirac operator eigenvalue : an update: Based on the exact relationship to random matrix theory, we present an\nalternative method of evaluating the probability distribution of the k-th\nsmallest Dirac eigenvalue in the epsilon-regime of QCD and QCD-like theories.\nBy utilizing the Nystrom-type discretization of Fredholm determinants and\nPfaffians, practical trouble of evaluating multiple integrations is\ncircumvented and technical restrictions on the parities of the number of\nflavors and of the topological charge present in our previous treatment for\nbeta=1 and 4 cases [Phys. Rev. D 63, 045012 (2001)] are partly lifted. This\nmethod is also applied to the distributions of spacings between k-th\nnearest-neighboring levels in the mobility edges of Anderson Hamiltonian and\nDirac operator in high-temperature QCD."
    },
    {
        "anchor": "Electromagnetic finite-size effects to the hadronic vacuum polarization: In order to reduce the current hadronic uncertainties in the theory\nprediction for the anomalous magnetic moment of the muon, lattice calculations\nneed to reach sub-percent accuracy on the hadronic-vacuum-polarization\ncontribution. This requires the inclusion of $\\mathcal{O}(\\alpha)$\nelectromagnetic corrections. The inclusion of electromagnetic interactions in\nlattice simulations is known to generate potentially large finite-size effects\nsuppressed only by powers of the inverse spatial extent. In this paper we\nderive an analytic expression for the $\\mathrm{QED}_{\\mathrm{L}}$ finite-volume\ncorrections to the two-pion contribution to the hadronic vacuum polarization at\nnext-to-leading order in the electromagnetic coupling in scalar QED. The\nleading term is found to be of order $1/L^{3}$ where $L$ is the spatial extent.\nA $1/L^{2}$ term is absent since the current is neutral and a photon far away\nthus sees no charge and we show that this result is universal. Our analytical\nresults agree with results from the numerical evaluation of loop integrals as\nwell as simulations of lattice scalar $U(1)$ gauge theory with stochastically\ngenerated photon fields. In the latter case the agreement is up to\nexponentially suppressed finite-volume effects. For completeness we also\ncalculate the hadronic vacuum polarization in infinite volume using a basis of\n2-loop master integrals.",
        "positive": "The finite temperature phase transition from domain wall fermions: We present results on the finite temperature QCD transition with 2+1 flavors\nusing Domain Wall Fermions (DWF) with the Dislocation Suppressing Determinant\nRatio (DSDR). In particular, we discuss how the use of DSDR allows us to study\nthe finite temperature transition at the coarse lattice spacings corresponding\nto the transition region (T = 139 - 195 MeV) with DWF at N_\\tau = 8. The\nresidual chiral symmetry breaking at these lattice spacings is sufficiently\nsmall so that a constant pion mass of m_\\pi \\approx 200 MeV is obtained in our\ncalculations. The strange quark mass is set to near its physical value. We show\nresults on the restoration of chiral symmetry and deconfinement at finite\ntemperature."
    },
    {
        "anchor": "Non-perturbative determination of Z_A^{stat} in quenched QCD: We non-perturbatively calculate the renormalization factor of the static\naxial vector current in O(a) improved quenched lattice QCD. Its scale\ndependence is mapped out in the Schroedinger functional scheme by means of a\nrecursive finite-size scaling technique, taking the continuum limit in each\nstep. We also obtain Z_A^{stat} for Wilson fermions in order to renormalize\nexisting unimproved data on F_B^{bare} non-perturbatively.",
        "positive": "Finite-volume formalism in the $2 \\xrightarrow[]{H_I+H_I} 2$ transition:\n  an application to the lattice QCD calculation of double beta decays: We present the formalism for connecting a second-order electroweak\n$2\\xrightarrow[]{H_I+H_I}2$ transition amplitudes in the finite volume (with\ntwo hadrons in the initial and final states) to the physical amplitudes in the\ninfinite volume. Our study mainly focus on the case where the low-lying\nintermediate state consists of two scattering hadrons. As a side product we\nalso reproduce the finite-volume formula for $2\\xrightarrow[]{H_I}2$\ntransition, originally obtained by Brice\\~no and Hansen. With the available\nfinite-volume formalism, we further discuss how to treat with the finite-volume\nproblem in the double beta decays $nn\\to pp ee\\bar{\\nu}\\bar{\\nu}$ and $nn\\to pp\nee$."
    },
    {
        "anchor": "Semileptonic form factors for $B \\to D^\\ast\\ell\u03bd$ at nonzero recoil\n  from 2 + 1-flavor lattice QCD: We present the first unquenched lattice-QCD calculation of the form factors\nfor the decay $B\\rightarrow D^\\ast\\ell\\nu$ at nonzero recoil. Our analysis\nincludes 15 MILC ensembles with $N_f=2+1$ flavors of asqtad sea quarks, with a\nstrange quark mass close to its physical mass. The lattice spacings range from\n$a\\approx 0.15$ fm down to $0.045$ fm, while the ratio between the light- and\nthe strange-quark masses ranges from 0.05 to 0.4. The valence $b$ and $c$\nquarks are treated using the Wilson-clover action with the Fermilab\ninterpretation, whereas the light sector employs asqtad staggered fermions. We\nextrapolate our results to the physical point in the continuum limit using\nrooted staggered heavy-light meson chiral perturbation theory. Then we apply a\nmodel-independent parametrization to extend the form factors to the full\nkinematic range. With this parametrization we perform a joint\nlattice-QCD/experiment fit using several experimental datasets to determine the\nCKM matrix element $|V_{cb}|$. We obtain $\\left|V_{cb}\\right| = (38.40 \\pm\n0.68_{\\textrm{th}} \\pm 0.34_{\\textrm{exp}} \\pm 0.18_{\\textrm{EM}})\\times\n10^{-3}$. The first error is theoretical, the second comes from experiment and\nthe last one includes electromagnetic and electroweak uncertainties, with an\noverall $\\chi^2\\text{/dof} = 126/84$, which illustrates the tensions between\nthe experimental data sets, and between theory and experiment. This result is\nin agreement with previous exclusive determinations, but the tension with the\ninclusive determination remains. Finally, we integrate the differential decay\nrate obtained solely from lattice data to predict $R(D^\\ast) = 0.265 \\pm\n0.013$, which confirms the current tension between theory and experiment.",
        "positive": "The hadronic vacuum polarization of the muon from four-flavor lattice\n  QCD: We present an update on the ongoing calculations by the Fermilab Lattice,\nHPQCD, and MILC Collaboration of the leading-order (in electromagnetism)\nhadronic vacuum polarization contribution to the anomalous magnetic moment of\nthe muon. Our project employs ensembles with four flavors of highly improved\nstaggered fermions, physical light-quark masses, and four lattice spacings\nranging from $a \\approx 0.06$ to 0.15 fm for most of the results thus far."
    },
    {
        "anchor": "Decay constants with Wilson fermions at $\u03b2=6.0$: We present results of a high statistics study of $f_\\pi$, $f_K$, $f_D$,\n$f_{D_s}$, and $f_V^{-1}$ in the quenched approximation using Wilson fermions\nat $\\beta=6.0$ on $32^3 \\times 64$ lattices. We find that the various sources\nof systematic errors (due to setting the quark masses, renormalization\nconstant, and lattice scale) are now larger than the statistical errors. Our\nbest estimates, without extrapolation to the continuum limit, are $f_\\pi=134(4)\n\\MeV$, $f_K =159(3) \\MeV$, $f_D = 229(7) \\MeV$, $f_{D_s} = 260(4) \\MeV$, and\n$f_V^{-1}(m_\\rho) = 0.33(1)$, where only statistical errors have been shown. We\ndiscuss the extrapolation to the continuum limit by combining our data with\nthose from other collaborations.",
        "positive": "P-vortices, nexuses and effects of gauge copies: We perform the careful study of the gauge copies problem for the direct\ncenter projection in SU(2) lattice gauge theory. Our results indicate that this\ngauge is not appropriate for the investigation of the center vortices. We also\nshow that the point-like objects, nexuses, are important for the confinement\ndynamics."
    },
    {
        "anchor": "Acceleration of the Arnoldi method and real eigenvalues of the\n  non-Hermitian Wilson-Dirac operator: In this paper, we present a method for the computation of the low-lying real\neigenvalues of the Wilson-Dirac operator based on the Arnoldi algorithm. These\neigenvalues contain information about several observables. We used them to\ncalculate the sign of the fermion determinant in one-flavor QCD and the sign of\nthe Pfaffian in N=1 super Yang-Mills theory. The method is based on polynomial\ntransformations of the Wilson-Dirac operator, leading to considerable\nimprovements of the computation of eigenvalues. We introduce an iterative\nprocedure for the construction of the polynomials and demonstrate the\nimprovement in the efficiency of the computation. In general, the method can be\napplied to operators with a symmetric and bounded eigenspectrum.",
        "positive": "Tensor renormalization group study of the non-Abelian Higgs model in two\n  dimensions: We study the $SU(2)$ gauge-Higgs model in two Euclidean dimensions using the\ntensor renormalization group (TRG) approach. We derive a tensor formulation for\nthis model in the unitary gauge and compare the expectation values of different\nobservables between TRG and Monte Carlo simulations finding excellent agreement\nbetween the two methods. In practice we find the TRG method to be far superior\nto Monte Carlo simulation for calculations of the Polyakov loop correlation\nfunction which is used to extract the static quark potential."
    },
    {
        "anchor": "A lattice calculation of the pion form factor with Ginsparg-Wilson-type\n  fermions: Results for Monte Carlo calculations of the electromagnetic vector and scalar\nform factors of the pion in a quenched simulation are presented. We work with\ntwo different lattice volumes up to a spatial size of 2.4 fm at a lattice\nspacing of 0.148 fm. The pion form factors in the space-like region are\ndetermined for pion masses down to 340 MeV.",
        "positive": "QED effects in the pseudoscalar meson sector: We present results on the pseudoscalar meson masses from a fully dynamical\nsimulation of QCD+QED. We concentrate particularly on violations of isospin\nsymmetry. We calculate the $\\pi^+$-$\\pi^0$ splitting and also look at other\nisospin violating mass differences. We have presented results for these isospin\nsplittings in arXiv:1508.06401 [hep-lat]. In this paper we give more details of\nthe techniques employed, discussing in particular the question of how much of\nthe symmetry violation is due to QCD, arising from the different masses of the\n$u$ and $d$ quarks, and how much is due to QED, arising from the different\ncharges of the quarks. This decomposition is not unique, it depends on the\nrenormalisation scheme and scale. We suggest a renormalisation scheme in which\nDashen's theorem for neutral mesons holds, so that the electromagnetic\nself-energies of the neutral mesons are zero, and discuss how the self-energies\nchange when we transform to a scheme such as $\\bar{MS}$, in which Dashen's\ntheorem for neutral mesons is violated."
    },
    {
        "anchor": "Equation of state and speed of sound of isospin-asymmetric QCD on the\n  lattice: We determine the QCD equation of state at nonzero temperature in the presence\nof an isospin asymmetry between the light quark chemical potentials on the\nlattice. Our simulations employ $N_f=2+1$ flavors of dynamical staggered quarks\nat physical masses, using three different lattice spacings. The main results\nare based on a two-dimensional spline interpolation of the isospin density,\nfrom which all relevant quantities can be obtained analytically. In particular,\nwe present results for the pressure, the interaction measure, the energy and\nentropy densities, as well as the speed of sound. Remarkably, the latter is\nfound to exceed its ideal gas limit deep in the pion condensed phase, the first\naccount of the violation of this limit in first principles QCD. Finally, we\nalso compute the phase diagram in the temperature -- isospin density plane for\nthe first time. The data for all observables will be useful for the\nbenchmarking of effective theories and low-energy models of QCD and are\nprovided in ancillary files for simple reuse.",
        "positive": "Leading hadronic contribution to the muon magnetic moment from lattice\n  QCD: We compute the leading order hadronic vacuum polarization (LO-HVP)\ncontribution to the anomalous magnetic moment of the muon, $(g_\\mu-2)$, using\nlattice QCD. Calculations are performed with four flavors of 4-stout-improved\nstaggered quarks, at physical quark masses and at six values of the lattice\nspacing down to 0.064~fm. All strong isospin breaking and electromagnetic\neffects are accounted for to leading order. The infinite-volume limit is taken\nthanks to simulations performed in volumes of sizes up to 11~fm. Our result for\nthe LO-HVP contribution to $(g_\\mu-2)$ has a total uncertainty of 0.8\\%.\nCompared to the result of the dispersive approach for this contribution, ours\nsignificantly reduces the tension between the standard model prediction for\n$(g_\\mu-2)$ and its measurement."
    },
    {
        "anchor": "On the phase diagram of 2d Lorentzian Quantum Gravity: The phase diagram of 2d Lorentzian quantum gravity (LQG) coupled to conformal\nmatter is studied. A phase transition is observed at $c=c_{\\rm crit}$\n($1/2<c_{\\rm crit}<4$) which can be thought of as the analogue of the $c=1$\nbarrier of Euclidean quantum gravity (EQG). The non--trivial properties of the\nquantum geometry are discussed.",
        "positive": "The 4D SU(3) gauge theory with an imaginary theta term: We study the scaling behavior of the 4D SU(3) lattice gauge theory in the\npresence of a theta term, by Monte Carlo simulations computing the topological\nproperties at imaginary theta. The numerical results provide a good evidence of\nscaling in the continuum limit. The imaginary theta dependence of the\nground-state energy turns out to be well described by the first few terms of\nrelated expansions around theta=0, providing accurate estimates of the first\nfew coefficients, up to O(theta^6)."
    },
    {
        "anchor": "Is trivial the antiferromagnetic RP(2) model in four dimensions?: We study the antiferromagnetic RP(2) model in four dimensions. We find a\nsecond order transition with two order parameters, one ferromagnetic and the\nother antiferromagnetic. The antiferromagnetic sector has mean-field critical\nexponents and a renormalized coupling which goes to zero in the continuum\nlimit. The exponents of the ferromagnetic channel are not the mean-field ones,\nbut the difference can be interpreted as logarithmic corrections. We perform a\ndetailed analysis of these corrections and conclude the triviality of the\ncontinuum limit of this model.",
        "positive": "The anomalous magnetic moment of the muon: status of Lattice QCD\n  calculations: In recent years, the anomalous magnetic moment of the muon has triggered a\nlot of activity in the lattice QCD community because a persistent tension of\nabout $3.5~\\sigma$ is observed between the phenomenological estimate and the\nBrookhaven measurement. The current best phenomenological estimate has an\nuncertainty comparable to the experimental one and the error is completely\ndominated by hadronic effects: the leading order hadronic vacuum polarization\n(HVP) contribution and the hadronic light-by-light (HLbL) scattering\ncontribution. Both are accessible via lattice simulations and a reduction of\nthe error by a factor 4 is required in view of the forthcoming experiments at\nFermilab and J-PARC whose results, expected in the next few years, should\nreduce the experimental precision down to the level of $0.14~$ppm. In this\narticle, I review the status of lattice calculations of those quantities,\nstarting with the HVP. This contribution has now reached sub-percent precision\nand requires a careful understanding of all sources of systematic errors. The\nHLbL contribution, that is much smaller, still contributes significantly to the\nerror. This contribution is more challenging to compute, but rapid progress has\nbeen made on the lattice in the last few years."
    },
    {
        "anchor": "Light-cone PDFs and GPDs from Lattice QCD: In this article, we review recent lattice calculations on the $x$-dependence\nof PDFs and GPDs from lattice QCD.",
        "positive": "Numerical confirmation of analytic predictions for the finite volume\n  mass gap of the XY-model: Recent exact predictions for the massive scaling limit of the two dimensional\nXY-model are based on the equivalence with the sine-Gordon theory and include\ndetailed results on the finite size behavior. The so-called step-scaling\nfunction of the mass gap is simulated with very high precision and found\nconsistent with analytic results in the continuum limit. To come to this\nconclusion, an also predicted form of a logarithmic decay of lattice artifacts\nwas essential to use for the extrapolation."
    },
    {
        "anchor": "B-meson decay constants from improved lattice NRQCD and physical u, d, s\n  and c sea quarks: We present the first lattice QCD calculation of the decay constants f_B and\nf_{B_s} with physical light quark masses. We use configurations generated by\nthe MILC collaboration including the effect of u, d, s and c HISQ sea quarks at\nthree lattice spacings and with three u/d quark mass values going down to the\nphysical value. We use improved NRQCD for the valence b quarks. Our results are\nf_B = 0.186(4) GeV, f_{B_s} = 0.224(5) GeV, f_{B_s}/f_B = 1.205(7) and\nM_{B_s}-M_B=85(2) MeV, superseding earlier results with NRQCD b quarks. We\ndiscuss the implications of our results for the Standard Model rates for B_s ->\nmu+ mu- and B -> tau nu.",
        "positive": "Performance of lattice QCD programs on CP-PACS: The CP-PACS is a massively parallel MIMD computer with the theoretical peak\nspeed of 614 GFLOPS which has been developed for computational physics\napplications at the University of Tsukuba, Japan. We report on the performance\nof the CP-PACS computer measured during recent production runs using our\nQuantum Chromodynamics code for the simulation of quarks and gluons in particle\nphysics. With the full 2048 processing nodes, our code shows a sustained speed\nof 237.5 GFLOPS for the heat-bath update of gluon variables, 264.6 GFLOPS for\nthe over-relaxation update, and 325.3 GFLOPS for quark matrix inversion with an\neven-odd preconditioned minimal residual algorithm."
    },
    {
        "anchor": "Radiative decay of the resonant $K^*$ and the $\u03b3K \\to K \u03c0$\n  amplitude from lattice QCD: We present the first calculation in lattice QCD of the process $\\gamma K \\to\nK\\pi$ in which the narrow $K^*$ vector resonance appears. Using a lattice on\nwhich the pion has a mass of 284 MeV, we determine the transition amplitude at\n128 points in the $(Q^2, E_{K\\pi})$ plane, and find suitable resonant\nscattering descriptions. We demonstrate the need to account for $S$--wave\n$K\\pi$ elastic scattering when converting the finite-volume matrix elements\ncomputed in lattice QCD to the physically relevant infinite-volume matrix\nelements, even when we are primarily interested in the $P$--wave amplitude.\nAnalytically continuing parameterizations of the $\\gamma K \\to K\\pi$ amplitude\nto the $K^*$ resonance pole, we obtain the $K^{*+} \\to K^+ \\gamma$ transition\nform-factor, and compare the $Q^2=0$ value to the corresponding value extracted\nfrom the experimental partial-decay width.",
        "positive": "String tension and removal of lattice coarsening effects in Monte Carlo\n  Renormalization Group: We study the computation of the static quark potential under decimations in\nthe Monte Carlo Renormalization Group (MCRG). Employing a multi-representation\nplaquette action, we find that fine-tuning the decimation prescription so that\nthe MCRG equilibrium self-consistency condition is satisfied produces dramatic\nimprovement at large distances. In particular, lattice coarsening (change of\neffective lattice spacing on action-generated lattices after decimation) is\nnearly eliminated. Failure to correctly tune the decimation, on the other hand,\nproduces large coarsening effects, of order 50% or more, consistent with those\nseen in previous studies. We also study rotational invariance restoration at\nshort distances, where no particular improvement is seen for this action."
    },
    {
        "anchor": "Parton distribution functions beyond leading twist from lattice QCD: The\n  $h_L(x)$ case: We report the first-ever calculation of the isovector flavor combination of\nthe chiral-odd twist-3 parton distribution $h_L(x)$ for the proton from lattice\nQCD. We employ gauge configurations with two degenerate light, a strange and a\ncharm quark ($N_f=2+1+1$) of maximally twisted mass fermions with a clover\nimprovement. The lattice has a spatial extent of 3 fm and lattice spacing of\n0.093 fm. The values of the quark masses lead to a pion mass of $260$ MeV. We\nuse a source-sink time separation of 1.12 fm to control contamination from\nexcited states. Our calculation is based on the quasi-distribution approach,\nwith three values for the proton momentum: 0.83 GeV, 1.25 GeV, and 1.67 GeV.\nThe lattice data are renormalized non-perturbatively using the RI$'$ scheme,\nand the final result for $h_L(x)$ is presented in the $\\overline{\\rm MS}$\nscheme at the scale of 2 GeV. Furthermore, we compute in the same setup the\ntransversity distribution, $h_1(x)$, which allows us, in particular, to compare\n$h_L(x)$ to its Wandzura-Wilczek approximation. We also combine results for the\nisovector and isoscalar flavor combinations to disentangle the individual quark\ncontributions for $h_1(x)$ and $h_L(x)$, and address the Wandzura-Wilczek\napproximation in that case as well.",
        "positive": "Quarkonium correlators and spectral functions at zero and finite\n  temperature from Fermilab action: We study charmonium and bottomonium systems at zero and finite temperatures\nusing Lattice QCD with Fermilab action on anisotropic lattices."
    },
    {
        "anchor": "Finite Temperature QCD on the Lattice -- Status 2010: In the last couple of years, there has been big progress in finite\ntemperature QCD on the lattice. Large-scale dynamical simulations of 2+1 flavor\nQCD with various improved staggered quark actions have been started to produce\nresults for various thermodynamic quantities which are extrapolated to the\ncontinuum limit at around physical quark masses, and thus are capable for a\ndirect comparison with experiment. At the same time, the theoretical uneasiness\nwith staggered-type lattice quarks motivated several groups to accelerate\nstudies with Wilson-type quarks and lattice chiral quarks. In this review, I\ndiscuss these important developments in finite temperature QCD made in the past\nyear.",
        "positive": "Combining the complex Langevin method and the generalized\n  Lefschetz-thimble method: The complex Langevin method and the generalized Lefschetz-thimble method are\ntwo closely related approaches to the sign problem, which are both based on\ncomplexification of the original dynamical variables. The former can be viewed\nas a generalization of the stochastic quantization using the Langevin equation,\nwhereas the latter is a deformation of the integration contour using the\nso-called holomorphic gradient flow. In order to clarify their relationship, we\npropose a formulation which combines the two methods by applying the former\nmethod to the real variables that parametrize the deformed integration contour\nin the latter method. Three versions, which differ in the treatment of the\nresidual sign problem in the latter method, are considered. By applying them to\na single-variable model, we find, in particular, that one of the versions\ninterpolates the complex Langevin method and the original Lefschetz-thimble\nmethod."
    },
    {
        "anchor": "RTNN: The new parallel machine in Zaragoza: I report on the development of RTNN, a parallel computer designed as a 4^4\nhypercube of 256 T9000 transputer nodes, each with 8 MB memory. The peak\nperformance of the machine is expected to be 2.5 Gflops.",
        "positive": "A calculation of the gauge anomaly with the chiral overlap operator: We investigate the property of the effective action with the chiral overlap\noperator, which was derived by Grabowska and Kaplan. They proposed a lattice\nformulation of four-dimensional chiral gauge theory, which is derived from\ntheir domain-wall formulation. In this formulation, an extra dimension is\nintroduced and the gauge field along the extra dimension is evolved by the\ngradient flow. The chiral overlap operator satisfies the Ginsparg-Wilson\nrelation and only depends on the gauge fields on the two boundaries. In this\npaper, we start from the arbitrary even-dimensional chiral overlap operator. We\ntreat the gauge fields on the two boundaries independently, and derive the\ngeneral expression to calculate the gauge anomaly with the chiral overlap\noperator in the continuum limit. As a result, we show that the gauge anomalies\nwith the chiral overlap operator in two, four, and six dimensions in the\ncontinuum limit is equivalent to those known in the continuum theory up to\ntotal derivatives."
    },
    {
        "anchor": "Computer Stochastics in Scalar Quantum Field Theory: This is a series of lectures on Monte Carlo results on the non-perturbative,\nlattice formulation approach to quantum field theory. Emphasis is put on 4D\nscalar quantum field theory. I discuss real space renormalization group, fixed\npoint properties and logarithmic corrections, partition function zeroes, the\ntriviality bound on the Higgs mass, finite size effects, Goldstone bosons and\nchiral perturbation theory, and the determination of scattering phase shifts\nfor some scalar models.",
        "positive": "Semileptonic B to D decays at nonzero recoil with 2+1 flavors of\n  improved staggered quarks: The Fermilab Lattice-MILC collaboration is completing a comprehensive program\nof heavy-light physics on the MILC (2+1)-flavor asqtad ensembles with lattice\nspacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as\n1/20. We use the Fermilab interpretation of the clover action for heavy valence\nquarks and the asqtad action for light valence quarks. The central goal of the\nprogram is to provide ever more exacting tests of the unitarity of the CKM\nmatrix. We give a progress report on one part of the program, namely the\nanalysis of the semileptonic decay B to D at both zero and nonzero recoil.\nAlthough final results are not presented, we discuss improvements in the\nanalysis methods, the statistical errors, and the parameter coverage that we\nexpect will lead to a significant reduction in the final error for |V_cb| from\nthis decay channel."
    },
    {
        "anchor": "Partially quenched chiral perturbation theory without $\u03a6_0$: This paper completes the argument that lattice simulations of partially\nquenched QCD can provide quantitative information about QCD itself, with the\naid of partially quenched chiral perturbation theory. A barrier to doing this\nhas been the inclusion of $\\Phi_0$, the partially quenched generalization of\nthe $\\eta'$, in previous calculations in the partially quenched effective\ntheory. This invalidates the low energy perturbative expansion, gives rise to\nmany new unknown parameters, and makes it impossible to reliably calculate the\nrelation between the partially quenched theory and low energy QCD. We show that\nit is straightforward and natural to formulate partially quenched chiral\nperturbation theory without $\\Phi_0$, and that the resulting theory contains\nthe effective theory for QCD without the $\\eta'$. We also show that previous\nresults, obtained including $\\Phi_0$, can be reinterpreted as applying to the\ntheory without $\\Phi_0$. We contrast the situation with that in the quenched\neffective theory, where we explain why it is necessary to include $\\Phi_0$.\n  We also compare the derivation of chiral perturbation theory in partially\nquenched QCD with the standard derivation in unquenched QCD. We find that the\nformer cannot be justified as rigorously as the latter, because of the absence\nof a physical Hilbert space. Finally, we present an encouraging result:\nunphysical double poles in certain correlation functions in partially quenched\nchiral perturbation theory can be shown to be a property of the underlying\ntheory, given only the symmetries and some plausible assumptions.",
        "positive": "Canonical approach to finite density QCD with multiple precision\n  computation: We calculate the baryon chemical potential ($\\mu_B$) dependence of\nthermodynamic observables, i.e., pressure, baryon number density and\nsusceptibility by lattice QCD using the canonical approach. We compare the\nresults with those by the multi parameter reweighting (MPR) method; Both\nmethods give very consistent values in the regions where errors of the MPR are\nunder control. The canonical method gives reliable results over $\\mu_\nB/T=3$,with $T$ being temperature. Multiple precision operations play an\nimportant roll in the evaluation of canonical partition functions."
    },
    {
        "anchor": "Continuum extrapolation of energies of a four-quark system in lattice\n  gauge theory: A continuum extrapolation of static two- and four-quark energies calculated\nin quenched SU(2) lattice Monte Carlo is carried out based on Sommer's method\nof setting the scale. The beta-function is obtained as a side product of the\nextrapolations. Four-quark binding energies are found to be essentially\nconstant at beta >= 2.35 unlike the two-body potentials. A model for four-quark\nenergies, with explicit gluonic degrees of freedom removed, is fitted to these\nenergies and the behaviour of the parameters of the model is investigated. An\nextension of the model using the first excited states of the two-body gluon\nfield as additional basis states is found to be necessary for quarks at the\ncorners of regular tetrahedra.",
        "positive": "Topological susceptibility with the improved Asqtad action: As a test of the chiral properties of the improved Asqtad (staggered fermion)\naction, we have been measuring the topological susceptibility as a function of\nquark masses for 2 + 1 dynamical flavors. We report preliminary results, which\nshow reasonable agreement with leading order chiral perturbation theory for\nlattice spacing less than 0.1 fm. The total topological charge, however, shows\nstrong persistence over Monte Carlo time."
    },
    {
        "anchor": "Random Matrix Theory and Dirac Spectrum at Nonzero Temperature and\n  Density: We investigate the eigenvalue spectrum of the staggered Dirac matrix in SU(3)\ngauge theory and in full QCD as well as in quenched U(1) theory on various\nlattice sizes. As a measure of the fluctuation properties of the eigenvalues,\nwe study the nearest-neighbor spacing distribution, $P(s)$. We further study\nlattice QCD at nonzero chemical potential, $\\mu$, by constructing the spacing\ndistribution of adjacent eigenvalues in the complex plane. We find that in all\nregions of their phase diagrams, compact lattice gauge theories have bulk\nspectral correlations given by random matrix theory, which is an indication for\nquantum chaos.",
        "positive": "Dynamic Critical Behavior of the Swendsen-Wang Algorithm: The\n  Two-Dimensional 3-State Potts Model Revisited: We have performed a high-precision Monte Carlo study of the dynamic critical\nbehavior of the Swendsen-Wang algorithm for the two-dimensional 3-state Potts\nmodel. We find that the Li-Sokal bound ($\\tau_{int,E} \\geq const \\times C_H$)\nis almost but not quite sharp. The ratio $\\tau_{int,E} / C_H$ seems to diverge\neither as a small power ($\\approx 0.08$) or as a logarithm."
    },
    {
        "anchor": "Negative-parity Baryon Masses using an O(a)-improved Fermion Action: We present a calculation of the mass of the lowest-lying negative-parity\nJ=1/2- state in quenched QCD. Results are obtained using a non-perturbatively\nO(a)-improved clover fermion action, and a splitting is found between the mass\nof the nucleon and its parity partner. The calculation is performed on two\nlattice volumes and at three lattice spacings, enabling a study of both\nfinite-volume and finite lattice-spacing uncertainties. A comparison is made\nwith results obtained using the unimproved Wilson fermion action.",
        "positive": "A disorder parameter for dual superconductivity in gauge theories: A detailed discussion is given of the disorder parameter for dual\nsuperconductivity of lattice gauge theories, introduced in a previous paper,\nand of its relation to other approaches. New lattice data are reported. Among\nother results, we find that the dual superconductivity of compact U(1) is type\nII."
    },
    {
        "anchor": "Phase diagram of the three-dimensional NJL model: With the exception of confinement the three-dimensional Nambu-Jona-Lasinio\n(NJL_3) model incorporates many of the essential properties of QCD. We discuss\nthe critical properties of the model at nonzero temperature T and/or nonzero\nchemical potential $\\mu$. We show that the universality class of the thermal\ntransition is that of the d=2 classical spin model with the same symmetry. We\nprovide evidence for the existence of a tricritical point in the\n($\\mu$,temperature) plane. We also discuss numerical results by Hands et al.\nwhich showed that the system is critical for $\\mu>\\mu_c$ and the diquark\ncondensate is zero.",
        "positive": "Mass Renormalization of the Schwinger Model with Wilson and Staggered\n  Fermions in the Hamiltonian Lattice Formulation: Lattice computations in the Hamiltonian formulation have so far mainly\nfocused on staggered fermions. In these proceedings, we study Wilson fermions\nin the Hamiltonian formulation and propose a new method to determine the\nresulting mass shift. As a benchmark study, we examine the one-flavour\nSchwinger model with Wilson fermions and a topological $\\theta$-term using\nmatrix product states. Wilson fermions explicitly break chiral symmetry; thus,\nthe bare mass of the lattice model receives an additive renormalization. In\norder to measure this mass shift directly, we develop a method that is suitable\nfor the Hamiltonian formulation, which relies on the fact that the vacuum\nexpectation value of the electric field density vanishes when the renormalized\nmass is zero. We examine the dependence of the mass shift on the lattice\nspacing, the lattice volume, the $\\theta$-parameter, and the Wilson parameter.\nUsing the mass shift, we then perform the continuum extrapolation of the\nelectric field density and compare the resulting mass dependence to the\nanalytical predictions of mass perturbation theory. We demonstrate that\nincorporating the mass shift significantly improves the continuum\nextrapolation. Finally, we apply our method to the same model using staggered\nfermions instead of Wilson fermions and compare the resulting mass shift to\nrecent theoretical predictions."
    },
    {
        "anchor": "The ice-limit of Coulomb gauge Yang-Mills theory: In this paper we describe gauge invariant multi-quark states generalising the\npath integral framework developed by Parrinello, Jona-Lasinio and Zwanziger to\namend the Faddeev-Popov approach. This allows us to produce states such that,\nin a limit which we call the ice-limit, fermions are dressed with glue\nexclusively from the fundamental modular region associated with Coulomb gauge.\nThe limit can be taken analytically without difficulties, avoiding the Gribov\nproblem. This is llustrated by an unambiguous construction of gauge invariant\nmesonic states for which we simulate the static quark--antiquark potential.",
        "positive": "QCD in magnetic fields: from Hofstadter's butterfly to the phase diagram: I revisit the problem of a charged particle on a two-dimensional lattice\nimmersed in a constant (electro)magnetic field, and discuss the energy spectrum\n- Hofstadter's butterfly - from a new, quantum field theoretical perspective.\nIn particular, I point out that there is an intricate interplay between a) the\nstructure of the butterfly at low magnetic flux, b) the absence of asymptotic\nfreedom in QED and c) the enhancement of the quark condensate by a magnetic\nfield at zero temperature. I proceed to discuss the response of the QCD\ncondensate to the magnetic field at nonzero temperatures in four space-time\ndimensions, present the resulting phase diagram and compare it to low-energy\nmodel predictions."
    },
    {
        "anchor": "Moments of proton GPDs from the OPE of nonlocal quark bilinears up to\n  NNLO: For the first time, we present a lattice QCD determination of Mellin moments\nof unpolarized generalized parton distributions (GPDs) of the proton from an\nanalysis of the quasi-GPD matrix elements within the short-distance\nfactorization framework. We perform our calculation on an $N_f$=2+1+1 twisted\nmass fermions ensemble with a clover improvement at lattice spacing $a=0.093$\nfm and a pion mass of $m_\\pi=260$ MeV. Focusing on the zero-skewness case, the\niso-vector and iso-scalar quasi-GPDs are calculated from the $\\gamma_0$\ndefinition, as well as a recently proposed Lorentz-invariant definition. We\nutilize data on both symmetric and asymmetric kinematic frames, which allows us\nto obtain the Mellin moments for several values of the momentum transfer, $-t$,\nin the range 0.17 to $2.77~\\rm{GeV}^2$. We use the ratio scheme for GPDs, i.e.\nrenormalization group invariant ratios with leading-twist factorization formula\nand perturbatively calculated matching coefficients up to the\nnext-next-to-leading order (NNLO) to extract Mellin moments of GPDs, which are\nconsistent with renormalization-group improved results. We compare our\ndetermination from quasi-GPDs with the results extracted using standard\ncalculations of Mellin moments of local operators, specifically those related\nto the electromagnetic and gravitational form factors. We estimated the moments\nof GPDs up to the fifth ones for the first time. By extrapolating the Mellin\nmoments to $-t=0$, we obtained the quark charges, momentum fraction, as well as\nthe angular momentum contributions to the proton spin. The impact parameter\nspace interpretation of the GPD moments is discussed, which provides insights\ninto the spatial distribution of unpolarized quarks and their correlations in\nthe transverse plane of an unpolarized or transversely polarized proton.",
        "positive": "Comment on \"Superinstantons and the Reliability of Perturbation Theory\n  in Non-Abelian Models\": In a recent letter (hep-lat/9311019) A. Patrascioiu and E. Seiler argued that\nwhen taking into account \"superinstantons configurations\" the perturbative\nexpansion and the beta-function of the two-dimensional non-linear sigma-model\nare modified at two loops order. I point out that: (1) perturbation theory in a\nsuperinstanton background is infra-red singular beyond three loops; (2) the new\ninfra-red singular terms, which change the two loop terms, come from singular\noperators - describing superinstanton insertions - in the OPE; (3) taking into\naccount these operators, the beta-function is not modified. Therefore the\nresults of Patrascioiu and Seiler do not contradict perturbation theory."
    },
    {
        "anchor": "Tuning of the strange quark mass with optimal reweighting: Quark mass reweighting can be used to tune the mass of dynamical quarks. The\nbasic idea is to use gauge field ensembles generated at some bare mass\nparameters to evaluate observables at different bare sea quark masses. This\ninvolves the computation of so called reweighing factors which are given as\nratios of fermion determinants. In the case of simulations including the\nstrange quark, reweighting can be used to improve the approach towards physical\nquark masses. Optimal reweighting strategies combine a change of the strange\nquark mass with a change of the light quark masses in order to minimize the\nfluctuations of the reweighting factor. We present numerical test of such\nstrategies for recent CLS2 simulations and a software package for mass\nreweighting based on openQCD.",
        "positive": "Symmetry Breaking in an Extended O(2) Model: Motivated by attempts to quantum simulate lattice models with continuous\nAbelian symmetries using discrete approximations, we study an extended-O(2)\nmodel in two dimensions that differs from the ordinary O(2) model by the\naddition of an explicit symmetry breaking term $-h_q\\cos(q\\varphi)$. Its\ncoupling $h_q$ allows to smoothly interpolate between the O(2) model ($h_q=0$)\nand a $q$-state clock model ($h_q\\rightarrow\\infty$). In the latter case, a\n$q$-state clock model can also be defined for noninteger values of $q$. Thus,\nsuch a limit can also be considered as an analytic continuation of an ordinary\n$q$-state clock model to noninteger $q$. In previous work, we established the\nphase diagram for noninteger $q$ in the infinite coupling limit\n($h_q\\rightarrow\\infty$). We showed that there is a second-order phase\ntransition at low temperature and a crossover at high temperature. In this\nwork, we seek to establish the phase diagram at finite values of the coupling\nusing Monte Carlo and tensor methods. We show that for noninteger $q$, the\nsecond-order phase transition at low temperature and crossover at high\ntemperature persist to finite coupling. For integer $q=2,3,4$, we know there is\na second-order phase transition at infinite coupling (i.e. the well-known clock\nmodels). At finite coupling, we find that the critical exponents for $q=3,4$\nvary with the coupling, and for $q=4$ the transition may turn into a BKT\ntransition at small coupling. We comment on the similarities and differences of\nthe phase diagrams with those of quantum simulators of the Abelian-Higgs model\nbased on ladder-shaped arrays of Rydberg atoms."
    },
    {
        "anchor": "Exact results for supersymmetric quantum mechanics on the lattice: We discuss N=2 supersymmetric quantum mechanics on the lattice using the\nfermion loop formulation. In this approach the system naturally decomposes into\na bosonic and fermionic sector. This allows us to deal with the sign problem\narising in the context of broken supersymmetry due to the vanishing of the\nWitten index. Employing transfer matrix techniques we obtain exact results at\nfinite lattice spacing and are hence able to study how the continuum limit is\napproached. In particular, we determine how supersymmetry is restored and how,\nin the case of broken supersymmetry, the goldstino mode emerges.",
        "positive": "Roles of the color antisymmetric ghost propagator in the infrared QCD: The results of Coulomb gauge and Landau gauge lattice QCD simulation do not\nagree completely with continuum theory. There are indications that the ghost\npropagator in the infrared region is not purely color diagonal as in high\nenergy region. After presenting lattice simulation of configurations produced\nwith Kogut-Susskind fermion (MILC collaboration) and those with domain wall\nfermion (RBC/UKQCD collaboration), I investigate in triple gluon vertex and the\nghost-gluon-ghost vertex how the square of the color antisymmetric ghost\ncontributes. Then the effect of the vertex correction to the gluon propagator\nand the ghost propagator is investigated.\n  Recent Dyson-Schwinger equation analysis suggests the ghost dressing function\n$G(0)=$ finite and no infrared enhancement or $\\alpha_G=0$. But the ghost\npropagator renormalized by the loop containing a product of color antisymmetric\nghost is expected to behave as $< c\\bar c>_r =-\\frac{G(q^2)}{q^2}$ with\n$G(q^2)\\propto q^{-2(1+\\alpha_G)}$ with $\\alpha_G = 0.5$, if the fixed point\nscenario is valid. I interpret the $\\alpha_G=0$ solution should contain a\nvertex correction. The infrared exponent of our lattice Landau gauge gluon\npropagator of the RBC/UKQCD is $\\kappa=\\alpha_G=-0.5$ and that of MILC is about\n-0.7.\n  The implication for the Kugo-Ojima color confinement criterion, QCD effective\ncoupling and the Slavnov identity are given."
    },
    {
        "anchor": "Two Color Matter in the Quenched Approximation: We study a quenched SU(2) lattice gauge theory in 4d in which the spatial\ngauge ensemble $\\{U_i\\}$ is generated from a 3d gauge-Higgs model and the\ntimelike link variables are ``reconstructed'' from the Higgs fields. The\nresulting ensemble is used to study quenched quark propagation with non-zero\nchemical potential $\\mu$. While it proves possible to alter the strength of the\ninter-quark interaction by changing the parameters of the dimensionally reduced\nmodel, there is no evidence for any region of parameter space where quarks\nexhibit deconfined behaviour or thermodynamic observables scale as if there\nwere a Fermi surface.",
        "positive": "A General Method for Non-Perturbative Renormalization of Lattice\n  Operators: We propose a non-perturbative method for computing the renormalization\nconstants of generic composite operators. This method is intended to reduce\nsome systematic errors, which are present when one tries to obtain physical\npredictions from the matrix elements of lattice operators. We also present the\nresults of a calculation of the renormalization constants of several\ntwo-fermion operators, obtained, with our method, by numerical simulation of\n$QCD$, on a $16^3 \\times 32$ lattice, at $\\beta=6.0$. The results of this\nsimulation are encouraging, and further applications to four-fermion operators\nand to the heavy quark effective theory are proposed."
    },
    {
        "anchor": "Abelian dominance and the dual Meissner effect in local unitary gauges\n  in SU(2) gluodynamics: Performing highly precise Monte-Carlo simulations of SU(2) gluodynamics, we\nobserve for the first time Abelian dominance in the confining part of the\nstatic potential in local unitary gauges such as the F12 gauge. We also study\nthe flux-tube profile between the quark and antiquark in these local unitary\ngauges and find a clear signal of the dual Meissner effect. The Abelian\nelectric field is found to be squeezed into a flux tube by the monopole\nsupercurrent. This feature is the same as that observed in the non-local\nmaximally Abelian gauge. These results suggest that the Abelian confinement\nscenario is gauge independent. Observing the important role of space-like\nmonopoles in the Polyakov gauge also indicates that the monopoles defined on\nthe lattice do not necessarily correspond to those proposed by 't Hooft in the\ncontext of Abelian projection.",
        "positive": "Gradient flow and scale setting on MILC HISQ ensembles: We report on a scale determination with gradient-flow techniques on the\n$N_f=2+1+1$ highly improved staggered quark ensembles generated by the MILC\nCollaboration. The ensembles include four lattice spacings, ranging from\napproximately 0.15 to 0.06 fm, and both physical and unphysical values of the\nquark masses. The scales $\\sqrt{t_0}/a$ and $w_0/a$ and their tree-level\nimprovements, $\\sqrt{t_{0,{\\rm imp}}}$ and $w_{0,{\\rm imp}}$, are computed on\neach ensemble using Symanzik flow and the cloverleaf definition of the energy\ndensity $E$. Using a combination of continuum chiral-perturbation theory and a\nTaylor-series ansatz for the lattice-spacing and strong-coupling dependence,\nthe results are simultaneously extrapolated to the continuum and interpolated\nto physical quark masses. We determine the scales $\\sqrt{t_0} =\n0.1416({}_{-5}^{+8})$ fm and $w_0 = 0.1714({}_{-12}^{+15})$ fm, where the\nerrors are sums, in quadrature, of statistical and all systematic errors. The\nprecision of $w_0$ and $\\sqrt{t_0}$ is comparable to or more precise than the\nbest previous estimates, respectively. We then find the continuum mass\ndependence of $\\sqrt{t_0}$ and $w_0$, which will be useful for estimating the\nscales of new ensembles. We also estimate the integrated autocorrelation length\nof $\\langle E(t) \\rangle$. For long flow times, the autocorrelation length of\n$\\langle E \\rangle$ appears to be comparable to that of the topological charge."
    },
    {
        "anchor": "Fermion-scalar interactions with domain wall fermions: Domain wall fermions are defined on a lattice with an extra direction the\nsize of which controls the chiral properties of the theory. When gauge fields\nare coupled to domain wall fermions the extra direction is treated as an\ninternal flavor space. Here it is found that this is not the case for scalar\nfields. Instead, the interaction takes place only along the link that connects\nthe boundaries of the extra direction. This reveals a richness in the way\ndifferent spin particles are coupled to domain wall fermions. As an\napplication, 4-Fermi models are studied using large N techniques and the\nresults are supported by numerical simulations with N=2. It is found that the\nchiral properties of domain wall fermions in these models are good across a\nlarge range of couplings and that a phase with parity-flavor broken symmetry\ncan develop for negative bare masses if the number of sites along the extra\ndirection is finite.",
        "positive": "Color dependence of tensor and scalar glueball masses in Yang-Mills\n  theories: We report the masses of the lightest spin-0 and spin-2 glueballs obtained in\nan extensive lattice study of the continuum and infinite volume limits of\n$Sp(N_c)$ gauge theories for $N_c=2,4,6,8$. We also extrapolate the combined\nresults towards the large-$N_c$ limit. We compute the ratio of scalar and\ntensor masses, and observe evidence that this ratio is independent of $N_{c}$.\nOther lattice studies of Yang-Mills theories at the same space-time dimension\nprovide a compatible ratio. We further compare these results to various\nanalytical ones and discuss them in view of symmetry-based arguments related to\nthe breaking of scale invariance in the underlying dynamics, showing that a\nconstant ratio might emerge in a scenario in which the $0^{++}$ glueball is\ninterpreted as a dilaton state."
    },
    {
        "anchor": "Tetraquark interpolating fields in a lattice QCD investigation of the\n  $D_{s0}^\\ast(2317)$ meson: We investigate the $D_{s0}^\\ast(2317)$ meson using lattice QCD and\nconsidering correlation functions of several $\\bar{c} s$ two-quark and $\\bar{c}\ns (\\bar{u} u + \\bar{d} d)$ four-quark interpolating fields. These interpolating\nfields generate different structures in color, spin and position space\nincluding quark-antiquark pairs, tetraquarks and two-meson scattering states.\nFor our computation we use an ensemble simulated with pion mass $m_\\pi \\approx\n0.296 \\, \\textrm{GeV}$ and spatial volume of extent $2.90 \\, \\textrm{fm}$. We\nfind in addition to the expected spectrum of two-meson scattering states\nanother state around $60 \\, \\textrm{MeV}$ below the $D K$ threshold, which we\ninterpret as the $D_{s0}^\\ast(2317)$ meson. This state couples predominantly to\na quark-antiquark interpolating field and only weakly to a $D K$ two-meson\ninterpolating field. The coupling to the tetraquark interpolating fields is\nessentially zero, rendering a tetraquark interpretation of the\n$D_{s0}^\\ast(2317)$ meson rather unlikely. Moreover, we perform a scattering\nanalysis using L\\\"uscher's method and the effective range approximation to\ndetermine the $D_{s0}^\\ast(2317)$ mass for infinite spatial volume. We find\nthis mass $51 \\, \\textrm{MeV}$ below the $D K$ threshold, rather close to both\nour finite volume result and the experimentally observed value.",
        "positive": "Hadronic Parity Violation from 4-quark Interactions: We present an exploratory investigation of the parity odd $\\Delta I = 1$\npion-nucleon coupling $h_\\pi^1$ from lattice QCD. Based on the PCAC relation,\nwe study the parity-conserving effective Hamiltonian and extract the coupling\nby determining the nucleon mass splitting arising from the effective 4-quark\ninteractions using the Feynman-Hellmann theorem. We present preliminary results\nof the mass shift for a $32^3 \\times 64$ ensemble of $N_f = 2 + 1 + 1$ twisted\nmass fermions at pion mass $260$ MeV and lattice spacing $a = 0.097$ fm."
    },
    {
        "anchor": "The Yang-Mills deconfinement transition from a high temperature\n  expansion: The high temperature expansion is an analytical tool to study critical\nphenomena in statistical mechanics. We apply this method to 3d effective\ntheories of Polyakov loops, which have been derived from 4d lattice Yang-Mills\nby means of resummed strong coupling expansions. In particular, the Polyakov\nloop susceptibility is computed as a power series in the effective couplings. A\nPad\\'e analysis then provides the location of the phase transition in the\neffective theory, which can be mapped back to the parameters of 4d Yang-Mills.\nOur purely analytical results for the critical couplings $\\beta_c(N_\\tau)$\nagree to better than $10\\%$ with those from Monte Carlo simulations. For the\ncase of $SU(2)$, also the critical exponent $\\gamma$ is predicted accurately,\nwhile a first-order nature as for $SU(3)$ cannot be identified by a Pad\\'e\nanalysis. The method can be generalized to include fermions and finite density.",
        "positive": "Leading hadronic contributions to the running of the electroweak\n  coupling constants from lattice QCD: The quark-connected leading-order hadronic contributions to the running of\nthe electromagnetic fine structure constant, $\\alpha_{\\rm QED}$, and the weak\nmixing angle, $\\theta_W$, are determined by a four-flavour lattice QCD\ncomputation with twisted mass fermions. Full agreement of the results with a\nphenomenological analysis is observed with an even comparable statistical\nuncertainty. We show that the uncertainty of the lattice calculation is\ndominated by systematic effects which then leads to significantly larger errors\nthan obtained by the phenomenological analysis."
    },
    {
        "anchor": "The Pion-Nucleon sigma-Term with Dynamical Wilson Fermions: We calculate connected and disconnected contributions to the flavour singlet\nscalar density amplitude of the nucleon in a full QCD lattice simulation with\n$n_f=2$ dynamical Wilson fermions at $\\beta=5.6$ on a $16^3 \\times 32$ lattice.\nWe find that both contributions are of similar size at the light quark mass. We\narrive at the estimate $\\sigma_{\\pi N} = 18(5)$MeV. Its smallness is directly\nrelated to the apparent decrease of $u$, $d$ quark masses when unquenching QCD\nlattice simulations. The $y$ parameter can be estimated from a semi-quenched\nanalysis, in which there are no strange quarks in the sea, the result being\n$y=0.59(13)$.}",
        "positive": "Simulating the massive Schwinger model with chiral defect fermions: Some time ago Kaplan proposed a new model for the description of chiral\nfermions on the lattice by adding an extra dimension for the fermions. A\nvariant of this proposal was introduced by Shamir and can be used to describe\nvector-like theories in even dimensions. We used this model for the simulation\nof the massive Schwinger model at different gauge couplings. The prediction\nthat the fermion mass gets only multiplicative renormalization was tested and\nverified."
    },
    {
        "anchor": "On the nature of an emergent symmetry in QCD: Remarkable symmetry properties appear to arise in lattice calculations of\ncorrelation functions in which the lowest-lying eigenmodes of the Dirac\noperator in quark propagators are removed by hand. The Banks-Casher relation\nties the chiral condensate to the density of low lying modes; thus, it is\nplausible that removal of such modes could lead to a regime where spontaneous\nchiral symmetry breaking does not occur. Surprising, a pattern of identical\ncorrelation functions was observed that is larger than can be explained by a\nrestoration of chiral symmetry. This suggests that a larger symmetry---one that\nis not present in the QCD lagrangian---emerges when these modes are removed.\nPreviously it was argued that this emergent symmetry was SU(4). However, when\nthe low-lying modes are removed, the correlation functions of sources in the\nSU(4) 15-plet of spin-1 mesons appear to coincide with the correlation function\nof the SU(4) singlet. A natural explanation for this is an emergent symmetry\nlarger than SU(4). In this work, it is shown that there exists no continuous\nsymmetry whose generators in the field theory are spatial integrals of local\noperators that can account for the full pattern of identical correlation\nfunctions unless the apparent coincidence of the singlet channel with the\n15-plet is accidental.",
        "positive": "Finite-size scaling tests for SU(3) lattice gauge theory with color\n  sextet fermions: The observed slow running of the gauge coupling in SU(3) lattice gauge theory\nwith two flavors of color sextet fermions naturally suggests it is a theory\nwith one relevant coupling, the fermion mass, and that at zero mass correlation\nfunctions decay algebraically. I perform a finite-size scaling study on\nsimulation data at two values of the bare gauge coupling with this assumption\nand observe a common exponent for the scaling of the correlation length with\nthe fermion mass, y_m ~ 1.5. An analysis of the scaling of valence Dirac\neigenvalues at one of these bare couplings produces a similar number."
    },
    {
        "anchor": "Neutral B-meson mixing from full lattice QCD at the physical point: We calculate the bag parameters for neutral $B$-meson mixing in and beyond\nthe Standard Model, in full four-flavour lattice QCD for the first time. We\nwork on gluon field configurations that include the effect of $u$, $d$, $s$ and\n$c$ sea quarks with the Highly Improved Staggered Quark (HISQ) action at three\nvalues of the lattice spacing and with three $u/d$ quark masses going down to\nthe physical value. The valence $b$ quarks use the improved NRQCD action and\nthe valence light quarks, the HISQ action. Our analysis was blinded. Our\nresults for the bag parameters for all five operators are the most accurate to\ndate. For the Standard Model operator between $B_s$ and $B_d$ mesons we find:\n$\\hat{B}_{B_s}=1.232(53)$, $\\hat{B}_{B_d}=1.222(61)$. Combining our results\nwith lattice QCD calculations of the decay constants using HISQ quarks from the\nFermilab/MILC collaboration and with experimental values for $B_s$ and $B_d$\noscillation frequencies allows determination of the CKM elements $V_{ts}$ and\n$V_{td}$. We find $V_{ts} = 0.04189(93)$, $V_{td} = 0.00867(23)$ and\n$V_{ts}/V_{td} = 0.2071(27)$. Our results agree well (within $2\\sigma$) with\nvalues determined from CKM unitarity constraints based on tree-level processes\n(only). Using a ratio to $\\Delta M$ in which CKM elements cancel in the\nStandard Model, we determine the branching fractions\n${\\text{Br}}(B_s\\rightarrow \\mu^+\\mu^-) = 3.81(18) \\times 10^{-9}$ and\n${\\text{Br}}(B_d\\rightarrow \\mu^+\\mu^-) = 1.031(54) \\times 10^{-10}$. We also\ngive results for matrix elements of the operators $R_0$, $R_1$ and\n$\\tilde{R}_1$ that contribute to neutral $B$-meson width differences.",
        "positive": "Quark propagator from an improved staggered action in Laplacian and\n  Landau gauges: Studies of gauge dependent quantities are afflicted with Gribov copies, but\nLaplacian gauge fixing provides one possible solution to this problem. We\npresent results for the lattice quark propagator in both Landau and Laplacian\ngauges using standard and improved staggered quark actions. The standard\nKogut-Susskind action has errors of \\oa{2} while the improved ``Asqtad'' action\nhas \\oa{4}, \\oag{2}{2} errors and this improvement is seen in the quark\npropagator. We demonstrate the application of tree-level corrections to these\nactions and see that Landau and Laplacian gauges produce very similar results.\nIn addition, we test an ansatz for the quark mass function, with promising\nresults. In the chiral limit, the infrared quark mass, $M(q^2 = 0)$ is found to\nbe $260\\pm 20$ MeV."
    },
    {
        "anchor": "Tunneling and Energy Splitting in Ising Models: The energy splitting $E_{0a}$ in two and four dimensional Ising models is\nmeasured in a cylindrical geometry on finite lattices. By comparing to exact\nresults in the two dimensional Ising model we demonstrate that $E_{0a}$ can be\nextracted very reliably from Monte Carlo calculations in practice. In four\ndimensions we compare the measured $E_{0a}$ with two different theoretical\npredictions on the finite size behavior of the energy splitting. We find that\nour numerical data are in favor of the predictions based on the semiclassical\ndilute instanton gas approximation.",
        "positive": "Partial restoration of chiral symmetry inside hadrons: By using the overlap-Dirac operator eigenmodes, we investigate spatial\ndistribution of the chiral condensate around static color sources for both\nquark-antiquark and three quark systems. In the presence of color sources, a\ncharacteristic flux-tube structure appears among them, suggesting a linear\nconfining potential. We show that the magnitude of the condensate is reduced\ninside the color flux, which indicates the partial restoration of chiral\nsymmetry inside the \"hadrons.\" Considering a periodic box containing a static\nbaryon source, which mimics the \"nuclear matter,\" we estimate the chiral\nsymmetry restoration in the presence of finite baryon number density."
    },
    {
        "anchor": "A simple idea for Lattice QCD at finite density: We pursue the idea of adding the naive $\\mu N$ term, where $\\mu$ is the quark\nchemical potential and $N$ is the conserved quark number, to the lattice QCD\naction. While computations of higher order susceptibilities, required for\nestimating the location of the QCD critical point, need a lot fewer number of\nquark propagators at any order as a result, it has its problem. We discuss a\nsolution, and examine if it works.",
        "positive": "Lambda-Nucleon and Sigma-Nucleon interactions from lattice QCD with\n  physical masses: We present our recent study on baryon-baryon ($BB$) interactions from lattice\nQCD with almost physical quark masses corresponding to\n$(m_\\pi,m_K)\\approx(146,525)$ MeV and large volume $(La)^4=(96a)^4\\approx$ (8.1\nfm)$^4$. In order to perform a comprehensive study of $BB$ interactions based\non lattice QCD calculation with almost physical masses and to make better use\nof such large scale computer resources, a large number of $BB$ interactions\nfrom $NN$ to $\\Xi\\Xi$ are calculated simultaneously. In this report, we focus\non the strangeness $S=-1$ channels of the hyperon interactions by means of HAL\nQCD method. The coupled-channel HAL QCD method is briefly outlined. The\nsnapshots of central and tensor potentials in $^1S_0$ and $^3S_1-^3D_1$\nchannels are presented for $\\Lambda N$, $\\Sigma N$ (both the isospin $I=1/2,\n3/2$) and their coupled-channel systems."
    },
    {
        "anchor": "First results from a parametrized Fixed-Point QCD action: We have constructed a new fermion action which is an approximation to the\n(chirally symmetric) Fixed-Point action, containing the full Clifford algebra\nwith couplings inside a hypercube and paths built from renormalization group\ninspired fat links. We present an exploratory study of the light hadron\nspectrum and the energy-momentum dispersion relation.",
        "positive": "Use of stochastic sources for the lattice determination of light quark\n  physics: In this paper we investigate the benefits of using Z(2)xZ(2) single timeslice\nstochastic sources for the calculation of light quark physics on the lattice.\nMeson 2-point correlators measured using sources stochastic in only spin and\nthose stochastic in both spin and colour indices are compared to point source\ncorrelators on the unit gauge and on a 16^3 x 32 Domain Wall QCD ensemble. It\nis found that the use of stochastic sources gives a considerable improvement in\nstatistics for the same computational cost. The neutral kaon mixing matrix\nelement B_K is also calculated on this ensemble with stochastic sources, but we\nconclude that the stochastic method offers no significant advantage over the\ntraditional gauge-fixed wall source approach which already offers an exact\nvolume average. We also discuss the application to semileptonic form factors in\nconjunction with partially twisted boundary conditions."
    },
    {
        "anchor": "Abelian Dyons in the Maximal Abelian Projection of SU(2) Gluodynamics: Correlations of the topological charge Q, the electric current J^e and the\nmagnetic current J^m in SU(2) lattice gauge theory in the Maximal Abelian\nprojection are investigated. It occurs that the correlator <<QJ^e J^m>> is\nnonzero for a wide range of values of the bare charge. It is shown that: (i)\nthe abelian monopoles in the Maximal Abelian projection are dyons which carry\nfluctuating electric charge; (ii) the sign of the electric charge e(x)\ncoincides with that of the product of the monopole charge m(x) and the\ntopological charge density Q(x).",
        "positive": "Spectrum of three-body bound states in a finite volume: The spectrum of a bound state of three identical particles with a mass $m$ in\na finite cubic box is studied. It is shown that in the unitary limit, the\nenergy shift of a shallow bound state is given by $\\Delta E=c\n(\\kappa^2/m)\\,(\\kappa L)^{-3/2}|A|^2\\exp(-2\\kappa L/\\sqrt{3})$, where $\\kappa$\nis the bound-state momentum, $L$ is the box size, $|A|^2$ denotes the\nthree-body analog of the asymptotic normalization coefficient of the bound\nstate wave function and $c$ is a numerical constant. The formula is valid for\n$\\kappa L\\gg 1$."
    },
    {
        "anchor": "Quenched Heavy-Light Decay Constants: We present decay constants from a quenched simulation using both propagating\nquarks and the static theory at $\\beta=6.2$ on $24^3\\times48$. The results\nusing propagating quarks are used to test scaling laws predicted by the heavy\nquark symmetry.",
        "positive": "Neutral meson oscillations on the lattice: Accurate measurements of K, D and B meson mixing amplitudes provide stringent\nconstraints in the Unitary Triangle analysis, as well as useful bounds on New\nPhysics scales. Lattice QCD provides a non perturbative tool to compute the\nhadronic matrix elements entering in the effective weak Hamiltonian, with\nerrors at a few percent level and systematic uncertainties under control. I\nreview recent lattice results for these hadronic matrix element performed with\n$N_f=2$, $N_f=2+1$ and $N_f=2+1+1$ dynamical sea quarks."
    },
    {
        "anchor": "Non-degenerate quark mass effect on $B_K$ with a mixed action: We investigate the effect of non-degenerate quarks on $B_K$. This effect is\nnoticeably large for $B_K$ (significantly larger than statistical uncertainty).\nHence, it is important to include this effect in order to determine $B_K$ with\nhigher precision. We also observe that the quality of fitting for $B_K$ gets\nbetter when we include non-degenerate combinations to fit to the prediction by\nVan de Water and Sharpe. However, this effect on $B_7^{(3/2)}$ and\n$B_8^{(3/2)}$ turns out to be relatively small.",
        "positive": "B-meson decay constants from 2+1-flavor lattice QCD with domain-wall\n  light quarks and relativistic heavy quarks: We calculate the B-meson decay constants f_B, f_Bs, and their ratio in\nunquenched lattice QCD using domain-wall light quarks and relativistic\nb-quarks. We use gauge-field ensembles generated by the RBC and UKQCD\ncollaborations using the domain-wall fermion action and Iwasaki gauge action\nwith three flavors of light dynamical quarks. We analyze data at two lattice\nspacings of a ~ 0.11, 0.086 fm with unitary pion masses as light as M_pi ~ 290\nMeV; this enables us to control the extrapolation to the physical light-quark\nmasses and continuum. For the b-quarks we use the anisotropic clover action\nwith the relativistic heavy-quark interpretation, such that discretization\nerrors from the heavy-quark action are of the same size as from the light-quark\nsector. We renormalize the lattice heavy-light axial-vector current using a\nmostly nonperturbative method in which we compute the bulk of the matching\nfactor nonperturbatively, with a small correction, that is close to unity, in\nlattice perturbation theory. We also improve the lattice heavy-light current\nthrough O(alpha_s a). We extrapolate our results to the physical light-quark\nmasses and continuum using SU(2) heavy-meson chiral perturbation theory, and\nprovide a complete systematic error budget. We obtain f_B0 = 199.5(12.6) MeV,\nf_B+ = 195.6(14.9) MeV, f_Bs = 235.4(12.2) MeV, f_Bs/f_B0 = 1.197(50), and\nf_Bs/f_B+ = 1.223(71), where the errors are statistical and total systematic\nadded in quadrature. These results are in good agreement with other published\nresults and provide an important independent cross check of other three-flavor\ndeterminations of $B$-meson decay constants using staggered light quarks."
    },
    {
        "anchor": "The Ising model universality of the electroweak theory: Lattice simulations have shown that the first order electroweak phase\ntransition turns into a regular cross-over at a critical Higgs mass m_{H,c}. We\nhave developed a method which enables us to make a detailed investigation of\nthe critical properties of the electroweak theory at m_{H,c}. We find that the\ntransition falls into the 3d Ising universality class. The continuum limit\nextrapolation of the critical Higgs mass is m_{H,c} = 72(2) GeV, which implies\nthat there is no electroweak phase transition in the Standard Model.",
        "positive": "Finite-temperature QCD: I start by discussing recent ideas concerning three different heavy quark\nrelated observables in finite-temperature QCD. Subsequently selected studies\nrelated to light quarks and gluons are reviewed, with a focus on thermodynamic\nobservables, screening masses, and sum rules."
    },
    {
        "anchor": "New features of the maximal abelian projection: After fixing the Maximal Abelian gauge in SU(2) lattice gauge theory we\ndecompose the nonabelian gauge field into the so called monopole field and the\nmodified nonabelian field with monopoles removed. We then calculate respective\nstatic potentials and find that the potential due to the modified nonabelian\nfield is nonconfining while, as is well known, the monopole field potential is\nlinear. Furthermore, we show that the sum of these potentials approximates the\nnonabelian static potential with 5% or higher precision at all distances\nconsidered. We conclude that at large distances the monopole field potential\ndescribes the classical energy of the hadronic string while the modified\nnonabelian field potential describes the string fluctuations. Similar\ndecomposition was observed to work for the adjoint static potential. A check\nwas also made of the center projection in the direct center gauge. Two static\npotentials, determined by projected $Z_2$ and by modified nonabelian field\nwithout $Z_2$ component were calculated. It was found that their sum is a\nsubstantially worse approximation of the SU(2) static potential than that found\nin the monopole case. It is further demonstrated that similar decomposition can\nbe made for the flux tube action/energy density.",
        "positive": "Quantum field-theoretic machine learning: We derive machine learning algorithms from discretized Euclidean field\ntheories, making inference and learning possible within dynamics described by\nquantum field theory. Specifically, we demonstrate that the $\\phi^{4}$ scalar\nfield theory satisfies the Hammersley-Clifford theorem, therefore recasting it\nas a machine learning algorithm within the mathematically rigorous framework of\nMarkov random fields. We illustrate the concepts by minimizing an asymmetric\ndistance between the probability distribution of the $\\phi^{4}$ theory and that\nof target distributions, by quantifying the overlap of statistical ensembles\nbetween probability distributions and through reweighting to complex-valued\nactions with longer-range interactions. Neural network architectures are\nadditionally derived from the $\\phi^{4}$ theory which can be viewed as\ngeneralizations of conventional neural networks and applications are presented.\nWe conclude by discussing how the proposal opens up a new research avenue, that\nof developing a mathematical and computational framework of machine learning\nwithin quantum field theory."
    },
    {
        "anchor": "S-wave charmed mesons in lattice NRQCD: Heavy-light mesons can be studied using the 1/M expansion of NRQCD, provided\nthe heavy quark mass is sufficiently large. Calculations of the S-wave charmed\nmeson masses from a classically and tadpole-improved action are presented. A\ncomparison of O(1/M), O(1/M^2) and O(1/M^3) results allows convergence of the\nexpansion to be discussed. It is shown that the form of discretized heavy quark\npropagation must be chosen carefully.",
        "positive": "Few-baryon interactions from lattice QCD: We report the recent progress on the determination of three-nucleon forces\n(3NF) in lattice QCD. We utilize the Nambu-Bethe-Salpeter (NBS) wave function\nto define the potential in quantum field theory, and extract two-nucleon forces\n(2NF) and 3NF on equal footing. The enormous computational cost for calculating\nmulti-baryon correlators on the lattice is drastically reduced by developing a\nnovel contraction algorithm (the unified contraction algorithm). Quantum\nnumbers of the three-nucleon (3N) system are chosen to be (I, J^P)=(1/2,1/2^+)\n(the triton channel), and we extract 3NF in which three nucleons are aligned\nlinearly with an equal spacing. Lattice QCD simulations are performed using\nN_f=2 dynamical clover fermion configurations at the lattice spacing of a =\n0.156 fm on a 16^3 x 32 lattice with a large quark mass corresponding to\nm(\\pi)= 1.13 GeV. Repulsive 3NF is found at short distance."
    },
    {
        "anchor": "Status of the MILC calculation of electromagnetic contributions to\n  pseudoscalar masses: We calculate pseudoscalar masses on gauge configurations containing the\neffects of 2+1 flavors of dynamical asqtad quarks and quenched\nelectromagnetism. The lattice spacings vary from 0.12 to 0.06 fm. The masses\nare fit with staggered chiral perturbation theory including NLO electromagnetic\nterms. We attempt to extract the fit parameters for the electromagnetic\ncontributions, while taking into account the finite volume effects, and\nextrapolate them to the physical limit.",
        "positive": "Chiral perturbation theory in a theta vacuum: We consider chiral perturbation theory (ChPT) with a non-zero theta term. Due\nto the CP violating term, the vacuum of chiral fields is shifted to a\nnon-trivial element on the SU(N_f) group manifold. The CP violation also\nprovides mixing of different CP eigenstates, between scalar and pseudoscalar,\nor vector and axialvector operators. We investigate upto O(theta^2) effects on\nthe mesonic two point correlators of ChPT to the one-loop order. We also\naddress the effects of fixing topology, by using saddle point integration in\nthe Fourier transform with respect to theta."
    },
    {
        "anchor": "Massive Schwinger model at finite $\u03b8$: Using the approach developed in [V. Azcoiti, G. Di Carlo, A. Galante, V.\nLaliena, \\textit{Phys. Lett.} \\textbf{B563}, (2003) 117], we are able to\nreconstruct the behavior of the massive 1-flavor Schwinger model with a\n$\\theta$ term and a quantized topological charge. We calculate the full\ndependence of the order parameter with $\\theta$. Our results at $\\theta = \\pi$\nare compatible with Coleman's conjecture on the phase diagram of this model.",
        "positive": "Improved gradient flow for step scaling function and scale setting: The gradient flow renormalized coupling offers a simple and relatively\ninexpensive way to calculate the step scaling function and the lattice scale,\nbut both applications can be hindered by large lattice artifacts. Recently we\nintroduced an empirical non-perturbative improvement that can reduce, even\nremove $\\mathcal{O}(a^2)$ lattice artifacts. The method is easy to implement\nand can be applied to any lattice gauge theory of interest both in step scaling\nstudies and for scale setting. In this talk I will briefly review this\nimprovement method and discuss its application for determining the discrete\n$\\beta$ function of the 8 and 12 flavor SU(3) systems and for improved scale\nsetting in 2+1+1 flavor QCD"
    },
    {
        "anchor": "Leading isospin breaking effects in the hadronic vacuum polarisation\n  with open boundaries: We discuss leading isospin breaking effects in the hadronic vacuum\npolarisation required for the investigation of the hadronic contribution to\n$(g-2)_{\\mu}$. The calculation proceeds by expanding the relevant correlation\nfunctions around the isosymmetric limit. Isosymmetric observables are evaluated\non gauge ensembles with $N_{f}=2+1$, $O(a)$ improved Wilson fermions and open\nboundary conditions generated by the CLS effort. Particular emphasis is placed\non the relevant quark-disconnected diagrams required for a complete treatment\nof leading isospin breaking effects in the valence quark sector. We provide a\ndetailed discussion of the renormalisation of the vector current in QCD+QED\ntaking operator mixing into account.",
        "positive": "Thirring model at finite density in 0+1 dimensions with stochastic\n  quantization: Crosscheck with an exact solution: We consider a generalized Thirring model in 0+1 dimensions at finite density.\nIn order to deal with the resulting sign problem we employ stochastic\nquantization, i.e., a complex Langevin evolution. We investigate the\nconvergence properties of this approach and check in which parameter regions\ncomplex Langevin evolutions are applicable in this setting. To this end we\nderive numerous analytical results and compare directly with numerical results.\nIn addition we employ indirect indicators to check for correctness. Finally we\ninterpret and discuss our findings."
    },
    {
        "anchor": "From Lattice Gauge Theories to Hydrogen Atoms: We construct canonical transformations to obtain a complete and most\neconomical realization of the physical Hilbert space ${\\cal H}^p$ of pure\n$SU(2)_{2+1}$ lattice gauge theory in terms of Wigner coupled Hilbert spaces of\nhydrogen atoms. One hydrogen atom is assigned to every plaquette of the\nlattice. A complete orthonormal description of the Wilson loop basis in ${\\cal\nH}^p$ is obtained by all possible angular momentum Wigner couplings of hydrogen\natom energy eigenstates $\\vert n~l~m\\rangle$ describing electric fluxes on the\nloops. The SU(2) gauge invariance implies that the total angular momenta of all\nhydrogen atoms vanish. The canonical transformations also enable us to rewrite\nthe Kogut-Susskind Hamiltonian in terms of fundamental Wilson loop operators\nand their conjugate electric fields. The resulting loop Hamiltonian has a\nglobal SU(2) invariance and a simple weak coupling ($g^2\\rightarrow 0$)\ncontinuum limit. The canonical transformations leading to the loop Hamiltonian\nare valid for any SU(N). The ideas and techniques can also be extended to\nhigher dimension.",
        "positive": "Quantum Spin-1/2 Antiferromagnetic Chains and Strongly Coupled\n  Multiflavor Schwinger Models: We review the correspondence between strongly coupled lattice multiflavor\nSchwinger models and SU(N) antiferromagnetic chains. We show that finding the\nlow lying states of the gauge models is equivalent to solving an SU(N)\nHeisenberg antiferromagnetic chain. For the two-flavor lattice Schwinger model\nthe massless excitations correspond to gapless states of the Heisenberg chain,\nwhile the massive states are created by fermion transport in the ground state\nof the spin chain. Our analysis shows explicitly how spinons may arise in\nlattice gauge theories."
    },
    {
        "anchor": "Symmetry Properties of Nonlocal Quark Bilinear Operators on a Lattice: Using symmetry properties, we determine the mixing pattern of a class of\nnonlocal quark bilinear operators containing a straight Wilson line along a\nspatial direction. We confirm the previous study that mixing among the lowest\ndimensional operators, which have mass dimension equals three, can occur if\nchiral symmetry is broken in the lattice action. For higher dimensional\noperators, we find that the dimension three operators will always mix with\ndimension four operators even if chiral symmetry is preserved. Also, the number\nof dimension four operators involved in the mixing is large hence it is\nimpractical to remove the mixing by the improvement procedure. Our result is\nimportant to determining the Bjorken-$x$ dependence parton distribution\nfunctions using the quasi-distribution method on a Euclidean lattice. The\nrequirement of using large hadron momentum in this approach makes the control\nof errors from dimension four operators even more important.",
        "positive": "Calculation of PCAC mass with Wilson fermion using gradient flow: We calculate the PCAC mass for $(2+1)$ flavor full QCD with Wilson-type\nquarks. We adopt the Small Flow-time eXpansion (SFtX) method based on the\ngradient flow which provides us a general way to compute correctly renormalized\nobservables even if the relevant symmetries for the observable are broken\nexplicitly due to the lattice regularization, such as the Poinc\\'{a}re and\nchiral symmetries. Our calculation is performed on heavy $u, d$ quarks mass\n($m_{\\pi}/m_{\\rho}\\simeq0.63$) and approximately physical $s$ quark mass with\nfine lattice $a \\simeq 0.07$~fm. The results are compared with those computed\nwith the Schr\\\"odinger functional method."
    },
    {
        "anchor": "Determination of $\u03b1_s(m_Z)$ by the non-perturbative decoupling\n  method: We present the details and first results of a new strategy for the\ndetermination of $\\alpha_s(m_Z)$. By simultaneously decoupling 3 fictitious\nheavy quarks we establish a relation between the $\\Lambda$-parameters of\nthree-flavor QCD and pure gauge theory. Very precise recent results in the pure\ngauge theory can thus be leveraged to obtain the three-flavour\n$\\Lambda$-parameter in units of a common decoupling scale. Connecting this\nscale to hadronic physics in 3-flavour QCD leads to our result in physical\nunits, $\\Lambda^{(3)}_{\\bar{\\rm MS}} = 336(12)\\, {\\rm MeV}$, which translates\nto $\\alpha_s(m_Z) = 0.11823(84)$. This is compatible with both the FLAG average\nand the previous ALPHA result, with a comparable, yet still statistics\ndominated, error. This constitutes a highly non-trivial check, as the\ndecoupling strategy is conceptually very different from the 3-flavour QCD\nstep-scaling method, and so are their systematic errors. These include the\nuncertainties of the combined decoupling and continuum limits, which we discuss\nin some detail. We also quantify the correlation between both results, due to\nsome common elements, such as the scale determination in physical units and the\ndefinition of the energy scale where we apply decoupling.",
        "positive": "Regularisation in Nonperturbative Extensions of Effective Field Theory: The process of renormalisation in nonperturbative Hamiltonian Effective Field\nTheory (HEFT) is examined in the $\\Delta$-resonance scattering channel. As an\nextension of effective field theory incorporating the L\\\"uscher formalism, HEFT\nprovides a bridge between the infinite-volume scattering data of experiment and\nthe finite-volume spectrum of energy eigenstates in lattice QCD. HEFT also\nprovides phenomenological insight into the basis-state composition of the\nfinite-volume eigenstates via the state eigenvectors. The Hamiltonian matrix is\nmade finite through the introduction of finite-range regularisation. The extent\nto which the established features of this regularisation scheme survive in HEFT\nis examined. In a single-channel $\\pi N$ analysis, fits to experimental phase\nshifts withstand large variations in the regularisation parameter, $\\Lambda$,\nproviding an opportunity to explore the sensitivity of the finite-volume\nspectrum and state composition on the regulator. While the L\\\"uscher formalism\nensures the eigenvalues are insensitive to $\\Lambda$ variation in the\nsingle-channel case, the eigenstate composition varies with $\\Lambda$; the\nadmission of short distance interactions diminishes single-particle\ncontributions to the states. In the two-channel $\\pi N$, $\\pi \\Delta$ analysis,\n$\\Lambda$ is restricted to a small range by the experimental data. Here the\ninelasticity is particularly sensitive to variations in $\\Lambda$ and its\nassociated parameter set. This sensitivity is also manifest in the\nfinite-volume spectrum for states near the opening of the $\\pi \\Delta$\nscattering channel. Finally, HEFT has the unique ability to describe the\nquark-mass dependence of the finite-volume eigenstates. The robust nature of\nthis capability is presented and used to confront current state-of-the-art\nlattice QCD calculations."
    },
    {
        "anchor": "The Gribov problem and its solution from a toy model point of view: The standard Faddeev Popov gauge fixing procedure is put on solid grounds by\ntaking into account a topological factor which corrects for the number of\nGribov copies within the first Gribov horizon. Zwanziger's stochastic approach\nto gauge fixed Yang-Mills theory is briefly reviewed. A simple toy model is\npresented which illustrates both methods. Within the toy model, I show that a\nstochastic drift force can be constructed with which the gauged configurations\nare attracted by the fundamental modular region. The toy model shows that an\naction which gives rise to the drift force can be found. This makes a ``heat\nbath'' simulation possible, which is seen to be superior to the Langevin\napproach at the numerical level.",
        "positive": "Axial symmetries in lattice QCD with Kaplan fermions: This paper develops in detail a lattice definition of QCD based on the chiral\ndefect fermions recently introduced by Kaplan. The revised version provides\nmissing technical details in the proof that non-singlet axial symmetries become\nexact in the limit of an infinite fifth dimension. Also several minor errors\nare corrected."
    },
    {
        "anchor": "Two-loop renormalization and mixing of gluon and quark energy-momentum\n  tensor operators: In this paper, we present one- and two-loop results for the renormalization\nof the gluon and quark gauge-invariant operators which appear in the definition\nof the QCD energy-momentum tensor, in dimensional regularization. To this end,\nwe consider a variety of Green's functions with different incoming momenta. We\nidentify the set of twist-2 symmetric traceless and flavor singlet operators\nwhich mix among themselves and we calculate the corresponding mixing\ncoefficients for the nondiagonal components. We also provide results for some\nappropriate regularization-independent (RI')-like schemes, which address this\nmixing, and we discuss their application to nonperturbative studies via lattice\nsimulations. Finally, we extract the one- and two-loop expressions of the\nconversion factors between the proposed RI' and the MSbar schemes. From our\nresults regarding the MSbar-renormalized Green's functions, one can easily\nderive conversion factors relating numerous variants of RI'-like schemes to\nMSbar.\n  To make our results easily accessible, we also provide them as Supplemental\nMaterial, in the form of a Mathematica input file and, also, an equivalent text\nfile.",
        "positive": "The Quantum Spacetime of c>0 2d Gravity: We review recent developments in the understanding of the fractal properties\nof quantum spacetime of 2d gravity coupled to c>0 conformal matter. In\nparticular we discuss bounds put by numerical simulations using dynamical\ntriangulations on the value of the Hausdorff dimension d_H obtained from\nscaling properties of two point functions defined in terms of geodesic\ndistance. Further insight to the fractal structure of spacetime is obtained\nfrom the study of the loop length distribution function which reveals that the\n0<c<= 1 system has similar geometric properties with pure gravity, whereas the\nbranched polymer structure becomes clear for c >= 5."
    },
    {
        "anchor": "$H$ dibaryon away from the $SU(3)_f$ symmetric point: We present the current status of our efforts in search of $H$ dibaryon on\n$N_f$=2+1 CLS ensembles away from the $SU(3)$ flavor symmetric point. Utilizing\nthe distillation framework (also known as LapH) in its exact and stochastic\nforms, we calculate two-point correlation matrices using large bases of\nbi-local two-baryon interpolators to reliably determine the low-energy spectra.\nWe report the low lying spectrum on several moving frames for multiple\nensembles with different lattice spacing and physical volumes. The status of\nfinite-volume analysis to extract the scattering amplitudes is also discussed.",
        "positive": "Chiral extrapolations and strangeness in the baryon ground states: We review the quark-mass dependence of the baryon octet and decuplet masses\nas obtained from recent lattice simulations of the BMW, PACS-CS, LHPC, HSC and\nQCDSF-UKQCD groups. Our discussion relies on the relativistic chiral Lagrangian\nand large-$N_c$ sum rule estimates of the counter terms relevant for the baryon\nmasses at N$^3$LO. A partial summation is implied by the use of physical baryon\nand meson masses in the one-loop contributions to the baryon self energies. In\nour analysis the physical masses are reproduced exactly by means of a suitable\nset of linear constraints. A quantitative and simultaneous description of all\nlattice results is achieved in terms of a six parameter fit, where the symmetry\nconserving counter term that are relevant at N$^3$LO are not yet being used.\nFor pion masses larger than 300 MeV there appears to be an approximate linear\npion-mass dependence of all octet and decuplet baryon masses. We discuss the\npion- and strangeness sigma terms of the baryon octet states."
    },
    {
        "anchor": "The Lattice Cutoff for $\u03bb\u03c6^4_4$ and $\u03bb\u03c6^6_3$: We analyze the critical line of $\\lambda\\phi^4_4$ perturbatively in the bare\ncoupling $\\lambda_0$, by setting the daisy-improved renormalized mass to zero.\nBy comparing to lattice data, we can then quantify the relation between the\ncontinuum cutoff and the lattice spacing; for the 4-dimensional hypercubic\nlattice we find $(\\Lambda a)_{C4} = 4.893$. We perform a similar analysis for\n$\\lambda\\phi^6_3$, and find in 3 dimensions $(\\Lambda a)_{C3} = 4.67$. We\npresent two theoretical predictions for $(\\Lambda a)$. For small $\\lambda_0$,\nboth the critical line and the renormalized mass near criticality are easily\nand accurately calculated from the lattice input parameters.",
        "positive": "Topological defects in lattice gauge theories: We present a non-perturbative formalism for measuring defect free energies\n(monopole mass or vortex tension) in three-dimensional SU(2)+adjoint Higgs\nmodels. Starting from twisted, translation invariant boundary conditions, we\nperform a change of variables that allows us to express the defect free\nenergies in terms of 't Hooft loops. We propose that the defect free energies\ncan be used to distinguish between phases in this model, and also more\ngenerally in other gauge field theories where no local order parameters exist.\nIn the case of monopoles, our construction can also be used in four-dimensional\npure-gauge SU(2) theory, where it gives the monopole mass in the maximally\nAbelian gauge without the need of actually fixing the gauge in the simulation.\nMoreover, the expression is manifestly independent of the choice of the Abelian\nprojection as long as it is compatible with the classical 't Hooft-Polyakov\nsolution."
    },
    {
        "anchor": "Finite Volume Scaling of Pseudo Nambu-Goldstone Bosons in QCD: We consider chiral perturbation theory in a finite volume and in a mixed\nregime of quark masses. We take N_l light quarks near the chiral limit, in the\nso-called epsilon-regime, while the remaining N_h quarks are heavier and in the\nstandard p-regime. We compute in this new mixed regime the finite-size scaling\nof the light meson correlators in the scalar, pseudoscalar, vector and axial\nvector channels.Using the replica method, we easily extend our results to the\npartially quenched theory. With the help of our results, lattice QCD\nsimulations with 2+1 flavors can safely investigate pion physics with very\nlight up and down quark masses even in the region where the pion's correlation\nlength overcomes the size of the space-time lattice.",
        "positive": "QCD phase diagram for nonzero isospin-asymmetry: The QCD phase diagram is studied in the presence of an isospin asymmetry\nusing continuum extrapolated staggered quarks with physical masses. In\nparticular, we investigate the phase boundary between the normal and the pion\ncondensation phases and the chiral/deconfinement transition. The simulations\nare performed with a small explicit breaking parameter in order to avoid the\naccumulation of zero modes and thereby stabilize the algorithm. The limit of\nvanishing explicit breaking is obtained by means of an extrapolation, which is\nfacilitated by a novel improvement program employing the singular value\nrepresentation of the Dirac operator. Our findings indicate that no pion\ncondensation takes place above $T\\approx 160$ MeV and also suggest that the\ndeconfinement crossover continuously connects to the BEC-BCS crossover at high\nisospin asymmetries. The results may be directly compared to effective theories\nand model approaches to QCD."
    },
    {
        "anchor": "Color Screening, Casimir Scaling, and Domain Structure in G(2) and SU(N)\n  Gauge Theories: We argue that screening of higher-representation color charges by gluons\nimplies a domain structure in the vacuum state of non-abelian gauge theories,\nwith the color magnetic flux in each domain quantized in units corresponding to\nthe gauge group center. Casimir scaling of string tensions at intermediate\ndistances results from random spatial variations in the color magnetic flux\nwithin each domain. The exceptional G(2) gauge group is an example rather than\nan exception to this picture, although for G(2) there is only one type of\nvacuum domain, corresponding to the single element of the gauge group center.\nWe present some numerical results for G(2) intermediate string tensions and\nPolyakov lines, as well as results for certain gauge-dependent projected\nquantities. In this context, we discuss critically the idea of projecting link\nvariables to a subgroup of the gauge group. It is argued that such projections\nare useful only when the representation-dependence of the string tension, at\nsome distance scale, is given by the representation of the subgroup.",
        "positive": "RG decimation-based approach to confinement and computation on coarser\n  lattices: A systematic procedure is presented for connecting short to long scales in\nLGT. Approximate decimations are used which can provide both upper and lower\nbounds on the partition function. Its exact value is then obtained by\ninterpolation between the bounds. By iterating the procedure representations of\nthe partition function as well as other physical quantities can be obtained on\nprogressively coarser lattices. For SU(2) IR flow into the confining strong\ncoupling regime results for any initial $\\beta$."
    },
    {
        "anchor": "2-loop additive mass renormalization with clover fermions and Symanzik\n  improved gluons: We calculate the critical value of the hopping parameter, kappa_c, in Lattice\nQCD, up to two loops in perturbation theory. We employ the\nSheikholeslami-Wohlert (clover) improved action for Wilson fermions and the\nSymanzik improved gluon action for 4- and 6-link loops.\n  The quantity which we study is a typical case of a vacuum expectation value\nresulting in an additive renormalization; as such, it is characterized by a\npower (linear) divergence in the lattice spacing, and its calculation lies at\nthe limits of applicability of perturbation theory.\n  Our results are polynomial in c_{SW} (clover parameter) and cover a wide\nrange of values for the Symanzik coefficients c_i. Furthermore, the dependence\non the number of colors N and the number of fermionic flavors N_f is shown\nexplicitly. In order to compare our results to non perturbative evaluations of\nkappa_c coming from Monte Carlo simulations, we employ an improved perturbation\ntheory method applied to improved actions.",
        "positive": "Towards a lattice determination of the $B^\\ast B \u03c0$ coupling: The coupling $g_{B^\\ast B \\pi}$ is related to the form factor at zero\nmomentum of the axial current between $B^\\ast$- and $B$-states. This form\nfactor is evaluated on the lattice using static heavy quarks and light quark\npropagators determined by a stochastic inversion of the fermionic bilinear. The\n$\\gBBP$ coupling is related to the coupling $g$ between heavy mesons and\nlow-momentum pions in the effective heavy meson chiral lagrangian. The coupling\nof the effective theory can therefore be computed by numerical simulations. We\nfind the value $g = 0.42(4)(8)$. Besides its theoretical interest, the\nphenomenological implications of such a determination are discussed."
    },
    {
        "anchor": "The quenched SU(2) scalar-gluon vertex in minimal Landau gauge: The question of whether confining effects are visible in correlation\nfunctions is a long-standing one. Complementing investigations on the\npropagators of fundamental and adjoint scalar matter particles here the\nquenched scalar-gluon vertex is investigated. For this purpose a multitude of\nlattice setups in two, three, and four dimensions is analyzed in quenched SU(2)\nlattice gauge theory. Though both cases are quantitatively different, neither a\nqualitative difference nor any singularities are observed.",
        "positive": "Universality, Scaling and Triviality in a Hierarchical Field Theory: Using polynomial truncations of the Fourier transform of the RG\ntransformation of Dyson's hierarchical model, we show that it is possible to\ncalculate very accurately the renormalized quantities in the symmetric phase.\nNumerical results regarding the corrections to the scaling laws, (i.e finite\ncut-off dependence) triviality, hyperscaling, universality and high-accuracy\ndeterminations of the critical exponents are discussed."
    },
    {
        "anchor": "Construction of energy-independent potentials above inelastic thresholds\n  in quantum field theories: We construct energy independent but non-local potentials above inelastic\nthresholds, in terms of Nambu-Bethe-Salpeter wave functions defined in quantum\nfield theories such as QCD. As an explicit example, we consider NN --> NN + n\npi scattering processes for n=0,1,2,.... We show an existence of\nenergy-independent coupled channel potentials with a non-relativistic\napproximation, where momenta of all particles are small compared with their own\nmasses. In the case of two-body inelastic scatterings such as Lambda Lambda -->\nLambda Lambda, N Xi, Sigma Sigma, on the other hand, we show that\nenergy-independent potentials can be constructed without relying on\nnon-relativistic approximations. We also propose a method to extract these\npotentials using time-dependence of general correlation functions.",
        "positive": "High-Temperature QCD: theory overview: We review the recent progress achieved in the theoretical investigation of\nQuantum Chromodynamics in the high temperature regime, with a focus on results\nachieved by lattice QCD simulations. The discussion covers the structure of the\nphase diagram and the properties of the strongly interacting medium at finite T\nand small baryon chemical potential."
    },
    {
        "anchor": "Double parton distributions in the pion from lattice QCD: We perform a lattice study of double parton distributions in the pion, using\nthe relationship between their Mellin moments and pion matrix elements of two\nlocal currents. A good statistical signal is obtained for almost all relevant\nWick contractions. We investigate correlations in the spatial distribution of\ntwo partons in the pion, as well as correlations involving the parton\npolarisation. The patterns we observe depend significantly on the quark mass.\nWe investigate the assumption that double parton distributions approximately\nfactorise into a convolution of single parton distributions.",
        "positive": "SU(N) polynomial integrals and some applications: We use the method of the Weingarten functions to evaluate SU(N) integrals of\nthe polynomial type. As an application we calculate various one-link integrals\nfor lattice gauge and spin SU(N) theories."
    },
    {
        "anchor": "Renormalization-group blocking the fourth root of the staggered\n  determinant: Lattice QCD simulations with staggered fermions rely on the ``fourth-root\ntrick.'' The validity of this trick has been proved for free staggered fermions\nusing renormalization-group block transformations. I review the elements of the\nconstruction and discuss how it might be generalized to the interacting case.",
        "positive": "Baryon Spectroscopy from Lattice QCD: Progress in extracting excited-state baryon masses in lattice QCD using large\nsets of spatially-extended operators is presented. The use of stochastic\nestimates of all-to-all quark propagators with variance reduction techniques is\ndescribed. Such techniques are crucial for incorporating multi-hadron operators\ninto the correlation matrices of the hadron operators."
    },
    {
        "anchor": "On pion and kaon decay constants and chiral SU(3) extrapolations: We consider the dependence of the pion and kaon decay constants on the up,\ndown and strange quark masses in QCD with strict isospin symmetry. The role of\ndynamical vector meson degrees of freedom is scrutinized in terms of an\neffective chiral Lagrangian for vector mesons. Applying a set of low-energy\nparameters as determined previously from QCD lattice data on the masses of the\nlight vector mesons from PACS-CS, QCDSF-UKQCD and HSC we compute its\nimplications on the pion and kaon decay constants for QCD lattice ensembles of\nHPQCD, CLS and ETMC. It is shown that with Gasser-Leutwyler L_4 and L_5\nparameters fixed to the empirical decay constants an accurate reproduction of\ntheir values at unphysical quark masses as computed by HPQCD, CLS and ETMC is\nachieved. Results for the masses of the light vector meson, the \\omega -\\phi\nmixing angles and the quark mass ratios for the ensembles used by HPQCD, CLS\nand ETMC are discussed.",
        "positive": "Dirac sheets and gauge fixing in $U(1)$ lattice gauge theory: Photon correlators in $~U(1)~$ pure gauge theory for different lattice\nactions are considered under the Lorentz gauge condition. They are shown to\ndepend strongly on the gauge fixing ambiguity and on the corresponding\nexistence of Dirac sheets. For the Coulomb phase a gauge fixing algorithm is\nproposed which avoids Dirac sheets and allows to find the global extremum of\nthe non-local gauge condition. Sorry, figures are not included and can be sent\nby ordinary mail."
    },
    {
        "anchor": "Recent progress in the effective string theory description of LGTs: In presence of a static pair of sources, the spectrum of low-lying states of\nany confining gauge theory in D space-time dimensions is described, at large\nsource separations, by an effective string theory. Recently two important\nadvances improved our understanding of this effective theory. First, it was\nrealized that the form of the effective action is strongly constrained by the\nrequirement of the Lorentz invariance of the gauge theory, which is\nspontaneously broken by the formation of a long confining flux tube in the\nvacuum. This constraint is strong enough to fix uniquely the first few\nsubleading terms of the action. Second, it has been realized that the first of\nthese allowed terms - a quartic polynomial in the field derivatives - is\nexactly the composite field $T\\bar{T}$, built with the chiral components, $T$\nand $\\bar{T}$, of the energy-momentum tensor of the 2d QFT describing the\ninfrared limit of the effective string. This irrelevant perturbation is quantum\nintegrable and yields, through the thermodynamic Bethe Ansatz (TBA), the energy\nlevels of the string which exactly coincide with the Nambu-Goto spectrum. In\nthis talk we first review the general implications of these two results and\nthen, as a test of the power of these methods, use them to construct the first\nfew boundary corrections to the effective string action.",
        "positive": "Two-loop critical mass for Wilson fermions: We have redone a recent two-loop computation of the critical mass for Wilson\nfermions in lattice QCD by evaluating Feynman integrals with the\ncoordinate-space method. We present the results for different types of infrared\nregularization. We confirm both the previous numerical estimates and the power\nof the coordinate-space method whenever high accuracy is needed."
    },
    {
        "anchor": "The quenched SU(2) adjoint scalar propagator in minimal Landau gauge: It is a long-standing question whether the confinement of matter fields in\nQCD has an imprint in the (gauge-dependent) correlation functions, especially\nthe propagators. In particular in the quenched case a fundamental difference\ncould be expected between adjoint and fundamental matter. In a preceding\ninvestigation the propagator of a fundamental scalar has been studied, showing\nno obvious sign of confinement. Here, complementary, the adjoint scalar\npropagator is investigated over a wide range of parameters in the minimal\nLandau gauge using lattice gauge theory. This study is performed in two, three,\nand four dimensions in quenched SU(2) Yang-Mills theory, both in momentum space\nand position space. No conclusive difference between both cases is found.",
        "positive": "On the Dynamics of Light Quarks in QCD: We describe recent results concerning the behavior of lattice QCD with light\ndynamical Wilson and Staggered quarks. We show that it is possible to reach\nregions of parameter space with light pions $m_\\pi\\approx 0.2/a$ using Wilson\nfermions. If the Hybrid Molecular Dynamics (HMD) algorithm is used with the\nsame parameters it gives incorrect results. We also present preliminary results\nusing a higher-order integration scheme."
    },
    {
        "anchor": "3--Dimensional Lattice Studies of the Electroweak Phase Transition at\n  M_{Higgs} approx 70 GeV: We study the electroweak phase transition by lattice simulations of an\neffective 3--dimensional theory, for a Higgs mass of about 70 GeV. Exploiting,\namong others, a variant of the equal weight criterion of phase equilibrium, we\nobtain transition temperature, latent heat and surface tension, and compare\nwith M_H approx 35 GeV. In the broken phase masses and Higgs condensates are\ncompared to perturbation theory. For the symmetric phase, bound state masses\nand the static force are determined.",
        "positive": "Heavy-Light Wavefunctions in Lattice QCD: Using a multistate smearing method, Coulomb gauge wave functions of\nheavy-light mesons are studied in lattice QCD. Wave functions for the ground\nstate, the first radially excited S-wave state, and the lowest P-wave states of\na heavy-light meson are calculated in quenched approximation. The results are\nfound to be in remarkably good agreement with the predictions of a simple\nrelativistic quark model."
    },
    {
        "anchor": "Probing the QCD vacuum with flavour singlet objects: $\u03b7'$ on the\n  lattice: We present a study on the direct determination of the $\\eta '$ mass on the\nfull set of SESAM and T$\\chi$L QCD vacuum configurations with 2 active flavours\nof Wilson fermions, at $\\beta = 5.6$. We observe a definite dependency of the\ntwo-loop correlator on the topological charge sector.",
        "positive": "Probing hadron wave functions in Lattice QCD: Gauge-invariant equal-time correlation functions are calculated in lattice\nQCD within the quenched approximation and with two dynamical quark species.\nThese correlators provide information on the shape and multipole moments of the\npion, the rho, the nucleon and the $\\Delta$."
    },
    {
        "anchor": "Continuum Limit of $2D$ Spin Models with Continuous Symmetry and\n  Conformal Quantum Field Theory: According to the standard classification of Conformal Quantum Field Theory\n(CQFT) in two dimensions, the massless continuum limit of the $O(2)$ model at\nthe Kosterlitz-Thouless (KT) transition point should be given by the massless\nfree scalar field; in particular the Noether current of the model should be\nproportional to (the dual of) the gradient of the massless free scalar field,\nreflecting a symmetry enhanced from $O(2)$ to $O(2)\\times O(2)$. More\ngenerally, the massless continuum limit of a spin model with a symmetry given\nby a Lie group $G$ should have an enhanced symmetry $G\\times G$. We point out\nthat the arguments leading to this conclusion contain two serious gaps: i) the\npossibility of `nontrivial local cohomology' and ii) the possibility that the\ncurrent is an ultralocal field. For the $2D$ $O(2)$ model we give analytic\narguments which rule out the first possibility and use numerical methods to\ndispose of the second one. We conclude that the standard CQFT predictions\nappear to be borne out in the $O(2)$ model, but give an example where they\nwould fail. We also point out that all our arguments apply equally well to any\n$G$ symmetric spin model, provided it has a critical point at a finite\ntemperature.",
        "positive": "Simple Observables from Fat Link Fermion Actions: A comparison is made of the (quenched) light hadron spectrum and of simple\nmatrix elements for a hypercubic fermion action (based on a fixed point action)\nand the clover action, both using fat links, at a lattice spacing a= 0.18 fm.\nRenormalization constants for the naive and improved vector current and the\nnaive axial current are computed using Ward identities. The renormalization\nfactors are very close to unity, and the spectroscopy of light hadrons and the\npseudoscalar and vector decay constants agree well with simulations at smaller\nlattice spacings (and with experiment)."
    },
    {
        "anchor": "Ergodic sampling of the topological charge using the density of states: In lattice calculations, the approach to the continuum limit is hindered by\nthe severe freezing of the topological charge, which prevents ergodic sampling\nin configuration space. In order to significantly reduce the autocorrelation\ntime of the topological charge, we develop a density of states approach with a\nsmooth constraint and use it to study SU(3) pure Yang Mills gauge theory near\nthe continuum limit. Our algorithm relies on simulated tempering across a range\nof couplings, which guarantees the decorrelation of the topological charge and\nergodic sampling of topological sectors. Particular emphasis is placed on\ntesting the accuracy, efficiency and scaling properties of the method. In their\nmost conservative interpretation, our results provide firm evidence of a\nsizeable reduction of the exponent z related to the growth of the\nautocorrelation time as a function of the inverse lattice spacing.",
        "positive": "Progress in the lattice simulations of Sp(2N) gauge theories: We report on the status of our programme to simulate Sp($2N$) gauge theories\non the lattice. Motivated by the potential realization of an\nSU($4$)/Sp($4$)$\\sim$SO($6$)/SO($5$) composite Higgs model and the applications\nto self interacting dark matter, we first perform dynamical simulations of\nSp($4$) theories with two Dirac flavors in the fundamental representation.\nPreliminary results of the meson spectrum are presented, along with discussion\nof the lattice systematics. We also introduce two-index anti-symmetric Dirac\nfermions. Such fermions are relevant in the context of partial top\ncompositeness, provided they carry SU($3$) color quantum numbers, and hence we\nintroduce three (Dirac) copies of them. We present the quenched meson spectrum\nand explore the phase space of bare lattice parameters. For all the numerical\nsimulations we use the standard Wilson lattice gauge and fermion actions."
    },
    {
        "anchor": "Positivity of the virial coefficients in lattice dimer models and upper\n  bounds on the number of matchings on graphs: Using a relation between the virial expansion coefficients of the pressure\nand the entropy expansion coefficients in the case of the monomer-dimer model\non infinite regular lattices, we have shown that, on hypercubic lattices of any\ndimension, the virial coefficients are positive through the 20th order. We have\nobserved that all virial coefficients so far known for this system are positive\nalso on infinite regular lattices with different structure. We are thus led to\nconjecture that the virial expansion coefficients $m_k $ are always positive.\nThese considerations can be extended to the study of related bounds on finite\ngraphs generalizing the infinite regular lattices, namely the finite grids and\nthe regular biconnected graphs. The validity of the bounds $\\Delta^k {\\rm\nln}(i! N(i)) \\le 0$ for $k \\ge 2$, where $N(i)$ is the number of configurations\nof $i$ dimers on the graph and $\\Delta$ is the forward difference operator, is\nshown to correspond to the positivity of the virial coefficients. Our tests on\nmany finite lattice graphs indicate that on large lattices these bounds are\nsatisfied, giving support to the conjecture on the positivity of the virial\ncoefficients. An exhaustive survey of some classes of regular biconnected\ngraphs with a not too large number $v$ of vertices shows only few violations of\nthese bounds. We conjecture that the frequency of the violations vanishes as $v\n\\to \\infty$. We find rigorous upper bounds on $N(i)$ valid for arbitrary graphs\nand for regular graphs. The similarity between the Heilman-Lieb inequality and\nthe one conjectured above suggests that one study the stricter inequality $m_k\n\\ge \\frac{1}{2k}$ for the virial coefficients, which is valid for all the known\ncoefficients of the infinite regular lattice models.",
        "positive": "Ginsparg-Wilson Relation and Lattice Chiral Symmetry in Fermionic\n  Interacting Theories: We derive Ginsparg-Wilson relation for a lattice chiral symmetry in theories\nwith self-interacting fermions. Auxiliary scalar and pseudo-scalar fields are\nintroduced on a coarse lattice to give an effective description of the\nfermionic interactions. We obtain particular solutions to the Ginsparg-Wilson\nrelation and other\n  Ward-Takahashi identities in a closed form. These non-perturbative solutions\ncan be used to construct a chiral invariant action and an invariant\npath-integral measure on the coarse lattice. The resulting partition function\nexhibits the exact chiral symmetry in the fermionic system with the auxiliary\nfields."
    },
    {
        "anchor": "QEX: a framework for lattice field theories: We present a new software framework for simulating lattice field theories. It\nfeatures an intuitive programming interface, while simultaneously achieving\nhigh performance supercomputing, all in one programming language, Nim. With a\nmacro system based on its abstract syntax tree, the language enables us to\ncheck and optimize our code at compile time. It also allows us to code\nintrinsics that map directly to machine instructions, and generates efficient\nnative code. We show how we use Nim's metaprogramming features in our code, and\npresent the current status of the code and future plans.",
        "positive": "Deconfinement and Chiral Symmetry Restoration in an SU(3) Gauge Theory\n  with Adjoint Fermions: We analyze the finite temperature phase diagram of$QC$ with fermions in the\nadjoint representation. The simulations performed with four dynamical Majorana\nfermions show that the deconfinement and chiral phase transitions occur at two\ndistinct temperatures. While the deconfinement transition is first order at T_d\nwe find evidence for a continuous chiral transition at a higher temperature\n$T_c ~ 8 T_d. We observe a rapid change of bulk thermodynamic observables at\nT_d which reflects the increase in the number of degrees of freedom. However,\nthese show little variation at T_c, where the fermion condensate vanishes. We\nalso analyze the potential between static fundamental and adjoint charges in\nall three phases and extract the corresponding screening masses above T_d."
    },
    {
        "anchor": "The lattice QCD phase diagram in and away from the strong coupling limit: We study lattice QCD with four flavors of staggered quarks. In the limit of\ninfinite gauge coupling, \"dual\" variables can be introduced, which render the\nfinite-density sign problem mild and allow a full determination of the $\\mu-T$\nphase diagram by Monte Carlo simulations, also in the chiral limit. However,\nthe continuum limit coincides with the weak coupling limit. We propose a\nstrong-coupling expansion approach towards the continuum limit. We show first\nresults, including the phase diagram and its chiral critical point, from this\nexpansion truncated to next-to-leading order.",
        "positive": "Correlation functions in lattice formulations of quantum gravity: We compare different models of a quantum theory of four-dimensional lattice\ngravity based on Regge's original proposal. From Monte Carlo simulations we\ncalculate two-point functions between geometrical quantities and estimate the\nmasses of the corresponding interaction particles."
    },
    {
        "anchor": "The Width of the Color Flux Tube at 2-Loop Order: The color flux tube connecting a static quark-anti-quark pair in Yang-Mills\ntheory supports massless transverse fluctuations, which are the Goldstone\nbosons of spontaneously broken translation invariance. Just as in chiral\nperturbation theory, the dynamics of these Goldstone bosons is described by a\nsystematic low-energy effective field theory. We use the effective theory to\ncalculate the width of the fluctuating string at the 2-loop level, using both\ncylindrical and toroidal boundary conditions. At zero temperature, the string\nwidth diverges logarithmically with the quark-anti-quark distance r. On the\nother hand, at low but non-zero temperature T = 1/\\beta, for r >> \\beta, the\nstring width diverges linearly.",
        "positive": "Static forces in d=2+1 SU(N) gauge theories: Using a three-level algorithm we perform a high-precision lattice computation\nof the static force up to 1fm in the 2+1 dimensional SU(5) gauge theory.\nDiscretization errors and the continuum limit are discussed in detail. By\ncomparison with existing SU(2) and SU(3) data it is found that \\sigma\nr_0^2=1.65-\\pi/24 holds at an accuracy of 1% for all N>=2, where r_0 is the\nSommer reference scale. The effective central charge c_{eff}(r) is obtained and\nan intermediate distance r_s is defined via the property c_{eff}(r_s)=\\pi/24.\nIt separates in a natural way the short-distance regime governed by\nperturbation theory from the long-distance regime described by an effective\nstring theory. The ratio r_s/r_0 decreases significantly from SU(2) to SU(3) to\nSU(5), where r_s < r_0. We give a preliminary estimate of its value in the\nlarge-N limit. The static force in the smallest representation of N-ality 2,\nwhich tends to the k=2 string tension as r->oo, is also computed up to 0.7fm.\nThe deviation from Casimir scaling is positive and grows from 0.1% to 1% in\nthat range."
    },
    {
        "anchor": "Supersymmetric lattices - a brief introduction: Recently, new theoretical ideas have allowed the construction of lattice\nactions which are explicitly invariant under one or more supersymmetries. These\ntheories are local and free of doublers and in the case of Yang-Mills theories\nalso possess exact gauge invariance. In this talk these ideas are reviewed with\nparticular emphasis being placed on ${\\cal N}=4$ super Yang-Mills theory.",
        "positive": "Calculation of $K \\to \u03c0\u03c0$ decay amplitudes with an improved Wilson\n  fermion action in a nonzero momentum frame in lattice QCD: We present our result for the $K\\to\\pi\\pi$ decay amplitudes for both the\n$\\Delta I=1/2$ and $3/2$ processes with the improved Wilson fermion action. In\norder to realize the physical kinematics, where the pions in the final state\nhave finite momenta, we consider the decay process $K({\\bf p}) \\to \\pi({\\bf p})\n+ \\pi({\\bf 0})$ in the nonzero momentum frame with momentum ${\\bf\np}=(0,0,2\\pi/L)$ on the lattice. Our calculations are carried out with\n$N_f=2+1$ gauge configurations generated with the Iwasaki gauge action and\nnonperturbatively $O(a)$-improved Wilson fermion action at $a=0.091\\,{\\rm fm}$\n($1/a=2.176\\,{\\rm GeV}$), $m_\\pi=260\\,{\\rm MeV}$, and $m_K=570\\,{\\rm MeV}$ on a\n$48^3\\times 64$ ($La=4.4\\,{\\rm fm}$) lattice. For these parameters the energy\nof the $K$ meson is set at that of two-pion in the final state. We obtain ${\\rm\nRe}A_2 = 2.431(19) \\times10^{ -8}\\,{\\rm GeV}$, ${\\rm Re}A_0 = 51(28) \\times10^{\n-8}\\,{\\rm GeV}$, and $\\epsilon'/\\epsilon = 1.9(5.7) \\times10^{-3}$ for a\nmatching scale $q^* =1/a$ where the errors are statistical. The dependence on\nthe matching scale $q^*$ of these values is weak. The systematic error arising\nfrom the renormalization factors is expected to be around $1.3\\%$ for ${\\rm\nRe}A_2$ and $11 \\%$ for ${\\rm Re}A_0$. Prospects toward calculations with the\nphysical quark mass are discussed."
    },
    {
        "anchor": "Confinement: Results and Perspectives: An updated review is presented of lattice investigations of colour\nconfinement.",
        "positive": "Path optimization method with use of neural network for the sign problem\n  in field theories: We investigate the sign problem in field theories by using the path\noptimization method with use of the neural network. For theories with the sign\nproblem, integral in the complexified variable space is a promising approach to\nobtain a finite (non-zero) average phase factor. In the path optimization\nmethod, the imaginary part of variables are given as functions of the real\npart, $y_i=y_i(\\{x\\})$, and are optimized to enhance the average phase factor.\nThe feedforward neural network can be used to give and to optimize functions\nwith many variables. The combined framework, the path optimization with use of\nthe neural network, is applied to the complex $\\phi^4$ theory at finite\ndensity, the 0+1 dimensional QCD at finite density, and the Polyakov loop\nextended Nambu-Jona-Lasinio (PNJL) model, all of which have the sign problem.\nIn these cases, the average phase factor is found to be enhanced significantly.\nIn the complex $\\phi^4$ theory, it is demonstrated that the number density is\ncalculated at a high precision. On the optimized path, the imaginary part is\nfound to have strong correlation with the real part on the temporal nearest\nneighbor site. In the 0+1 dimensional QCD, we compare the results in two\ndifferent treatments of the link variable: optimization after the diagonal\ngauge fixing and optimization without the diagonal gauge fixing. These two\nmethods show consistent eigenvalue distribution of the link variables. In the\nPNJL model with homogeneous field ansatz, finite volume results approach the\nmean field results as expected, and the phase transition behavior can be\ndescribed."
    },
    {
        "anchor": "Universality of the topological susceptibility in the SU(3) gauge theory: The definition and computation of the topological susceptibility in\nnon-abelian gauge theories is complicated by the presence of non-integrable\nshort-distance singularities. Recently, alternative representations of the\nsusceptibility were discovered, which are singularity-free and do not require\nrenormalization. Such an expression is here studied quantitatively, using the\nlattice formulation of the SU(3) gauge theory and numerical simulations. The\nresults confirm the expected scaling of the susceptibility with respect to the\nlattice spacing and they also agree, within errors, with computations of the\nsusceptibility based on the use of a chiral lattice Dirac operator.",
        "positive": "The pion quasiparticle in the low-temperature phase of QCD: We investigate the properties of the pion quasiparticle in the\nlow-temperature phase of two-flavor QCD on the lattice with support from chiral\neffective theory. We find that the pion quasiparticle mass is significantly\nreduced compared to its value in the vacuum, in contrast to the static\nscreening mass, which increases with temperature. By a simple argument, the two\nmasses are expected to determine the quasiparticle dispersion relation near the\nchiral limit. Analyzing two-point functions of the axial charge density at\nnon-vanishing spatial momentum, we find that the predicted dispersion relation\nand the residue of the pion pole are simultaneously consistent with the lattice\ndata at low momentum. The test, based on fits to the correlation functions, is\nconfirmed by a second analysis using the Backus-Gilbert method."
    },
    {
        "anchor": "Multichannel one-to-two transition amplitudes in a finite volume: We derive a model-independent expression for finite-volume matrix elements.\nSpecifically, we present a relativistic, non-perturbative analysis of the\nmatrix element of an external current between a one-scalar in-state and a\ntwo-scalar out-state. Our result, which is valid for energies below\nhigher-particle inelastic thresholds, generalizes the Lellouch-Luscher formula\nin two ways: we allow the external current to inject arbitrary momentum into\nthe system and we allow for the final state to be composed an arbitrary number\nof strongly coupled two-particle states with arbitrary partial waves (including\npartial-wave mixing induced by the volume). We also illustrate how our general\nresult can be applied to some key examples, such as heavy meson decays and\nmeson photo production. Finally, we point out complications that arise\ninvolving unstable resonance states, such as $B\\rightarrow K^*\\ell^+\\ell^-$\nwhen staggered or mixed-action/partially-quenched calculations are performed.",
        "positive": "The Compton amplitude and nucleon structure functions: Structure functions are the essential objects for understanding the deep\ninelastic scattering processes, providing valuable insight into the partonic\nstructure of hadrons. A direct calculation of the Compton amplitude provides a\ncomplementary way to accessing the structure functions, circumventing the\noperator mixing and renormalisation issues of the standard operator product\nexpansion approach. We describe the connection between the Compton amplitude\nand the structure functions, and describe a Feynman-Hellmann approach to\ncalculate the amplitude directly. As an application, we extract the moments of\ntransverse and longitudinal proton structure functions and study the power\ncorrections."
    },
    {
        "anchor": "Nonperturbative Studies of Quantum Gravity: One of several possibilities to construct a quantum theory of gravity is\nemploying the Feynman path integral. This approach is plagued by some problems:\nthe integration measure is not uniquely defined, the Einstein-Hilbert action\nunbounded, and perturbation theory nonrenormalizable. To make the path integral\ntractable one can approximate the continuous geometry of spacetime by a\nsimplicial complex. The edge lengths of this lattice are considered as the\ndynamical degrees of freedom and Regge calculus is applied. In this work,\nnumerical simulations using the Regge-Einstein action and a \"compact\" action\nshow the occurence of a phase transition. The strength of this transition,\nseparating a well-defined phase with finite expectation values from an\nill-defined phase, is weaker for the compact action, which might be important\nfor the continuum limit. To analyze the interaction mechanism of this\nformulation of quantum gravity, correlation functions between geometrical\nquantities like edge lengths, volume elements, and local curvatures have been\ncomputed. Our results for the two-point functions seem to prefer exchange\nparticles with an effective mass. To ease treatment of quantum gravity a new\napproach is proposed consisting in a transformation of the path integral to the\npartition function of a spin system. This facilitates analytical and numerical\ncalculations considerably. First results for the phase structure in two as in\nfour dimensions are presented and indicate promising similarities to the\noriginal Regge theory.",
        "positive": "Heavy Light Weak Matrix Elements: I review the status of lattice calculations of heavy-light weak matrix\nelements, concentrating on semileptonic B decays to light mesons, B -> K*\ngamma, the B meson decay constant, f_B, and the mixing parameter B_B."
    },
    {
        "anchor": "Four-dimensional lattice chiral gauge theories with anomalous fermion\n  content: In continuum field theory, it has been discussed that chiral gauge theories\nwith Weyl fermions in anomalous gauge representations (anomalous gauge\ntheories) can consistently be quantized, provided that some of gauge bosons are\npermitted to acquire mass. Such theories in four dimensions are inevitablly\nnon-renormalizable and must be regarded as a low-energy effective theory with a\nfinite ultraviolet (UV) cutoff. In this paper, we present a lattice framework\nwhich enables one to study such theories in a non-perturbative level. By\nintroducing bare mass terms of gauge bosons that impose ``smoothness'' on the\nlink field, we explicitly construct a consistent fermion integration measure in\na lattice formulation based on the Ginsparg-Wilson (GW) relation. This\nframework may be used to determine in a non-perturbative level an upper bound\non the UV cutoff in low-energy effective theories with anomalous fermion\ncontent. By further introducing the St\\\"uckelberg or Wess-Zumino (WZ) scalar\nfield, this framework provides also a lattice definition of a non-linear sigma\nmodel with the Wess-Zumino-Witten (WZW) term.",
        "positive": "Chiral symmetry and lattice fermions: Lattice gauge theory and chiral perturbation theory are among the primary\ntools for understanding non-perturbative aspects of QCD. I review several\nsubtle and sometimes controversial issues that arise when combining these\ntechniques. Among these are one failure of partially quenched chiral\nperturbation theory when the valence quarks become lighter than the average sea\nquark mass and a potential ambiguity in comparisons of perturbative and lattice\nproperties of non-degenerate quarks."
    },
    {
        "anchor": "The critical point of lattice QCD on the \u03bc-T plane: We propose a method to study lattice QCD at finite temperature and chemical\npotential. We compare it with direct results and with the Glasgow method by\nusing n_f=4 QCD at Im(\\mu)\\neq 0. We locate the critical endpoint (E) of QCD on\nthe Re(\\mu)-T plane. In this study we use n_f=2+1 dynamical staggered quarks\nwith semi-realistic masses on L_t=4 lattices.",
        "positive": "Glueball spectrum from $N_f=2$ lattice QCD study on anisotropic lattices: The lowest-lying glueballs are investigated in lattice QCD using $N_f=2$\nclover Wilson fermion on anisotropic lattices. We simulate at two different and\nrelatively heavy quark masses, corresponding to physical pion mass of\n$m_\\pi\\sim 938$ MeV and $650$ MeV. The quark mass dependence of the glueball\nmasses have not been investigated in the present study. Only the gluonic\noperators built from Wilson loops are utilized in calculating the corresponding\ncorrelation functions. In the tensor channel, we obtain the ground state mass\nto be 2.363(39) GeV and 2.384(67) GeV at $m_\\pi\\sim 938$ MeV and $650$ MeV,\nrespectively. In the pseudoscalar channel, when using the gluonic operator\nwhose continuum limit has the form of $\\epsilon_{ijk}TrB_iD_jB_k$, we obtain\nthe ground state mass to be 2.573(55) GeV and 2.585(65) GeV at the two pion\nmasses. These results are compatible with the corresponding results in the\nquenched approximation. In contrast, if we use the topological charge density\nas field operators for the pseudoscalar, the masses of the lowest state are\nmuch lighter (around 1GeV) and compatible with the expected masses of the\nflavor singlet $q\\bar{q}$ meson. This indicates that the operator\n$\\epsilon_{ijk}TrB_iD_jB_k$ and the topological charge density couple rather\ndifferently to the glueball states and $q\\bar{q}$ mesons. The observation of\nthe light flavor singlet pseudoscalar meson can be viewed as the manifestation\nof effects of dynamical quarks. In the scalar channel, the ground state masses\nextracted from the correlation functions of gluonic operators are determined to\nbe around 1.4-1.5 GeV, which is close to the ground state masses from the\ncorrelation functions of the quark bilinear operators. In all cases, the mixing\nbetween glueballs and conventional mesons remains to be further clarified in\nthe future."
    },
    {
        "anchor": "Meson spectrum in the large $N$ limit: We present the result of our computation of the lowest lying meson masses for\nSU(N) gauge theory in the large $N$ limit (with $N_f/N\\longrightarrow 0$). The\nfinal values are given in units of the square root of the string tension, and\nwith errors which account for both statistical and systematic errors. By using\n4 different values of the lattice spacing we have seen that our results scale\nproperly. We have studied various values of $N$ (169, 289 and 361) to monitor\nthe N-dependence of the most sensitive quantities. Our methodology is based\nupon a first principles approach (lattice gauge theory) combined with large $N$\nvolume independence. We employed both Wilson fermions and twisted mass fermions\nwith maximal twist. In addition to masses in the pseudoscalar, vector, scalar\nand axial vector channels, we also give results on the pseudoscalar decay\nconstant and various remormalization factors.",
        "positive": "Moments of pion distribution amplitude using operator product expansion\n  on the lattice: We report an exploratory study of the current-current matrix elements that\nare relevant to the extraction of moments of the pion light-cone distribution\namplitude, employing the method of introducing a valence relativistic heavy\nquark. The numerical investigation is carried out in the quenched approximation\nwith the physical volume $L\\approx 2.4$ fm at two values of lattice spacing\n(0.05 and 0.075 fm). We obtain clean signals for the relevant Euclidean\nhadronic tensor with reasonable statistics, but observe that the lattice\nartefacts are non-negligible in our results. The key conclusion from the\nanalysis hitherto is that although our approach has the potential for making\nsignificant contributions to parton physics, data at finer lattice spacings\nthat are currently being produced are needed in order to control the continuum\nextrapolation."
    },
    {
        "anchor": "Large-time correlation functions in bosonic lattice field theories: Large-time correlation functions have a pivotal role in extracting particle\nmasses from Euclidean lattice field theory calculations, however little is\nknown about the statistical properties of these quantities. In this work, the\nasymptotic form of the distributions of the correlation functions at vanishing\nmomentum is determined for bosonic interacting lattice field theories with a\nunique gapped vacuum. It is demonstrated that the deviations from the\nasymptotic form at large Euclidean times can be utilized to determine the\nspectrum of the theory.",
        "positive": "Transiting topological sectors with the overlap: The overlap operator provides an elegant definition for the winding number of\nlattice gauge field configurations. Only for a set of configurations of measure\nzero is this procedure undefined. Without restrictions on the lattice fields,\nhowever, the space of gauge fields is simply connected. I present a simple low\ndimensional illustration of how the eigenvalues of a truncated overlap operator\nflow as one travels between different topological sectors."
    },
    {
        "anchor": "Investigation of gauge-fixed pure U(1) theory at strong coupling: We numerically investigate the phase diagram of pure U(1) gauge theory with\ngauge fixing at strong gauge coupling. The FM-FMD phase transition, which\nproved useful in defining Abelian lattice chiral gauge theory, persists also at\nstrong gauge coupling. However, there the transition seems no to be longer\ncontinuous. At large gauge couplings we find evidences for confinement.",
        "positive": "On gauge fixing: Gauge fixing is a useful tool to simplify calculations. It is also valuable\nto combine different methods, in particular lattice and continuum methods.\nHowever, beyond perturbation theory the Gribov-Singer ambiguity requires\nfurther gauge conditions for a well-defined gauge-fixing prescription.\nDifferent additional conditions can, in principle, lead to different results\nfor gauge-dependent correlation functions, as will be discussed for the example\nof Landau gauge. Also the relation of lattice and continuum gauge fixing beyond\nperturbation theory will be briefly outlined."
    },
    {
        "anchor": "Topological Lattice Actions: We consider lattice field theories with topological actions, which are\ninvariant against small deformations of the fields. Some of these actions have\ninfinite barriers separating different topological sectors. Topological actions\ndo not have the correct classical continuum limit and they cannot be treated\nusing perturbation theory, but they still yield the correct quantum continuum\nlimit. To show this, we present analytic studies of the 1-d O(2) and O(3)\nmodel, as well as Monte Carlo simulations of the 2-d O(3) model using\ntopological lattice actions. Some topological actions obey and others violate a\nlattice Schwarz inequality between the action and the topological charge Q.\nIrrespective of this, in the 2-d O(3) model the topological susceptibility\n\\chi_t = \\l< Q^2 >/V is logarithmically divergent in the continuum limit.\nStill, at non-zero distance the correlator of the topological charge density\nhas a finite continuum limit which is consistent with analytic predictions. Our\nstudy shows explicitly that some classically important features of an action\nare irrelevant for reaching the correct quantum continuum limit.",
        "positive": "Light hadron properties with improved staggered quarks: Preliminary results from simulations with 2+1 dynamical quark flavors at a\nlattice spacing of 0.09 fm are combined with earlier results at a=0.13 fm. We\nexamine the approach to the continuum limit and investigate the dependence of\nthe pseudoscalar masses and decay constants as the sea and valence quark masses\nare separately varied."
    },
    {
        "anchor": "Logarithmic Corrections and Finite-Size Scaling in the Two-Dimensional\n  4-State Potts Model: We analyze the scaling and finite-size-scaling behavior of the\ntwo-dimensional 4-state Potts model. We find new multiplicative logarithmic\ncorrections for the susceptibility, in addition to the already known ones for\nthe specific heat. We also find additive logarithmic corrections to scaling,\nsome of which are universal. We have checked the theoretical predictions at\ncriticality and off criticality by means of high-precision Monte Carlo data.",
        "positive": "Solving the sign problem of two flavor scalar electrodynamics at finite\n  chemical potential: We explore two flavor scalar electrodynamics on the lattice, which has a\ncomplex phase problem at finite chemical potential. By rewriting the action in\nterms of dual variables this complex phase problem can be solved exactly. The\ndual variables are link- and plaquette occupation numbers, subject to local\nconstraints that have to be respected by the Monte Carlo algorithm. For the\nsimulation we use a local update as well as the newly developed \"surface worm\nalgorithm\", which is a generalization of the Prokof'ev Svistunov worm algorithm\nconcept for simulating the dual representation of abelian Gauge-Higgs models on\na lattice. We assess the performance of the two algorithms, present results for\nthe phase diagram and discuss condensation phenomena."
    },
    {
        "anchor": "Fast methods for computing the Neuberger Operator: I describe a Lanczos method to compute the Neuberger Operator and a multigrid\nalgorithm for its inversion.",
        "positive": "Scaling in a toy model of gluodynamics at finite temperatures: In the limit of $\\xi \\simeq a_\\sigma /a_\\tau \\to \\infty $ the gluodynamics\nwithout the magnetic part of action ($S_M\\sim 1/\\xi $) is considered as a\nself-contained model. The model is studied analytically in the continuum limit\non an extremely large lattice ($N_\\tau \\to \\infty $). Scaling conditions for\ncritical temperature and string tension are considered. The model shows trivial\n($g^2\\sim a_\\tau $) asymptotic freedom in the case of continuous gauge groups\nand nontrivial one ($g^2\\sim 1/\\ln 1/a_\\tau $) for discrete groups."
    },
    {
        "anchor": "Lattice Chiral Schwinger Model: Selected Results: We discuss a method for regularizing chiral gauge theories. The idea is to\nformulate the gauge fields on the lattice, while the fermion determinant is\nregularized and computed in the continuum. A simple effective action emerges\nwhich lends itself to numerical simulations.",
        "positive": "Perturbation Theory at Finite Extent of Fifth Dimension for Vacuum\n  Overlap Formula of Chiral Determinant -- Continuum Limit Case --: Taking into account of the boundary condition in the fifth direction which is\nderived from the lattice Wilson fermion, we develop a theory of\nfive-dimensional fermion with kink-like and homogeneous masses in finite extent\nof the fifth dimension. The boundary state wave functions are constructed\nexplicitly and the would-be vacuum overlap is expanded by using the propagator\nof the theory. The subtraction is performed unambiguously at the finite extent\nwith the help of the dimensional regularization. Then the limit of the infinite\nextent is evaluated. The consistent anomaly in four dimensional theory is\nfinitely obtained. Each contribution to the vacuum polarization is vector-like.\nIt is the lack of the massless mode in the fermion with negative homogeneous\nmass that leads to the correct chiral normalization. Gauge noninvariant piece\nremains due to the breaking of the boundary condition by the dimensional\nregularization."
    },
    {
        "anchor": "Status and Perspective of Non-perturbative Renormalization in Weak\n  Decays: We discuss the status and the problems related to the application of the\noff-shell non-perturbative renormalization method in a fixed gauge to operators\nrelevant to weak decays. In particular, we critically reappraise the method\nrecently proposed for the $\\Delta I=1/2$ rule. We also present a general\nanalysis of the renormalization for the $\\Delta I=3/2$ operators, and apply it\nto the $\\Delta S=2$ operator.",
        "positive": "Smooth flux-sheets with topological winding modes: The inclusion of the Gaussian-curvature term in the bulk of Polyakov-Kleinert\nstring action renders new boundary terms and conditions by Gauss-Bonnet\ntheorem. Within a leading approximation, the eigenmodes of smooth worldsheets\nand the free-energy of a gas of open rigid strings appears to be altered at\nsecond order in the coupling by the topological term . In analogy to the\ntopological $\\theta$ term, the Gauss-Bonnet term is introduced into the\neffective action with a complex coupling to implement signed energy shifts. We\ninvestigate the rigid color flux-sheets between two static color sources near\nthe critical point in the light of the topologically induced shifts. The\nYang-Mills lattice data of the potential of static quark-antiquark $Q\\bar{Q}$\nin a heatbath is compared to the string potential. The Monte-Carlo data\ncorrespond to link-integrated Polyakov-loop correlators averaged over SU(3)\ngauge configurations at $\\beta=6.0$. Substantial improvement in the fit\nbehavior is displayed over the nonperturbative source separation distance $0.2$\nfm to $1.0$ fm. Remarkably, the returned coupling parameter of the topological\nterm from the fit exhibits a proportionality to a quantum number. These\nfindings suggest that the manifested modes are the winding number of a\ntopological particle on the string's worldsheet."
    },
    {
        "anchor": "Proper heavy-quark potential from a spectral decomposition of the\n  thermal Wilson loop: We propose a non-perturbative and gauge invariant derivation of the static\npotential between a heavy-quark ($Q$) and an anti-quark ($\\bar{Q}$) at finite\ntemperature. This proper potential is defined through the spectral function\n(SPF) of the thermal Wilson loop and can be shown to satisfy the\nSchr\\\"{o}dinger equation for the heavy $Q\\bar{Q}$ pair in the thermal medium.\nIn general, the proper potential has a real and an imaginary part,corresponding\nto the peak position and width of the SPF. The validity of using a\nSchr\\\"{o}dinger equation for heavy $Q\\bar{Q}$ can also be checked from the\nstructure of the SPF. To test this idea, quenched QCD simulations on\nanisotropic lattices ($a_\\sigma=4a_\\tau=0.039\\rm fm$, $N^3_\\sigma \\times\nN_{\\tau} =20^2 \\times (96-32)$) are performed. The real part of the proper\npotential below the deconfinement temperature ($T=0.78T_c$) exhibits the well\nknown Coulombic and confining behavior. At ($T=2.33T_c$) we find that it\ncoincides with the Debye screened potential obtained from Polyakov-line\ncorrelations in the color-singlet channel under Coulomb gauge fixing. The\nphysical meaning of the spectral structure of the thermal Wilson loop and the\nuse of the maximum entropy method (MEM) to extract the real and imaginary part\nof the proper potential are also discussed.",
        "positive": "Energy-momentum tensor correlators and viscosity: Collective flow has been observed in heavy ion collisions, with a large\nanisotropic component, and ideal hydrodynamic calculations had significant\nsuccessful in describing the distribution of produced particles at the RHIC\nexperiments. In order to account for this near ideal fluid behavior, the shear\nand bulk viscosity of the quark gluon plasma (QGP) must be computed from first\nprinciples in a regime where the QGP is not weakly coupled. In this talk I\ndescribe recent progress in computing energy-momentum tensor correlators on the\nlattice from which the viscosities can be extracted via Kubo formulas. I also\nshow how to cumulate information from several channels, including at\nnon-vanishing spatial momentum, in order to best constrain the viscosities.\nThese methods should soon yield predictions at the higher temperatures that\nwill be explored at the LHC experiments."
    },
    {
        "anchor": "Computation of the Spatial String Tension in High Temperature SU(2)\n  Gauge Theory: A detailed investigation of the temperature dependence of the spatial string\ntension $\\sigma_s$ in $SU(2)$ gauge theory is presented. A sustained\nperformance of 3~GFLOPS on a 64K Connection Machine CM-2 equivalent has been\nachieved. Scaling of $\\sigma_s$ between $\\beta=2.5115$ and $\\beta=2.74$, on\nlarge lattices, is demonstrated. Below the critical temperature, $T_c$,\n$\\sigma_s$ remains constant. For temperatures larger than $2T_c$ the\ntemperature dependence can be parametrized by $\\sigma_s(T) = (0.369\\pm 0.014)^2\ng^4(T)T^2$, where $g(T)$ is a 2-loop running coupling constant with the scale\nparameter determined as $\\Lambda_T = (0.076\\pm 0.013)T_c$.",
        "positive": "Simulations of Alice Electrodynamics on a Lattice: In this paper we present results of numerical simulations and some\n(analytical) approximations of a compact $U(1)\\ltimes\\ZZ_2$ lattice gauge\ntheory, including an extra bare mass term for Alice fluxes. The subtle\ninterplay between Alice fluxes and (Cheshire) magnetic charges is analysed. We\ndetermine the phase diagram and some characteristics of the model in three and\nfour dimensions. The results of the numerical simulations in various regimes,\ncompare well with some analytic approximations."
    },
    {
        "anchor": "Precision $\u03a5$ Spectroscopy and Fundamental Parameters From NRQCD: We present results from a high precision NRQCD simulation of the quenched\n$\\Upsilon$ system at $\\beta = 6$. We demonstrate a variety of important lattice\ntechniques, including the perturbative improvement of actions, tadpole\nimprovement, and multicorrelated fits for extracting the spectrum of excited\nstates. We present new determinations of $\\alpha_s(M_Z)$ and $M_b$, two\nfundamental parameters of the Standard Model.",
        "positive": "New Analytical Results on Anisotropic Membranes: We report on recent progress in understanding the tubular phase of\nself-avoiding anisotropic membranes. After an introduction to the problem, we\nsketch the renormalization group arguments and symmetry considerations that\nlead us to the most plausible fixed point structure of the model. We then\nemploy an epsilon-expansion about the upper critical dimension to extrapolate\nto the physical interesting 3-dimensional case. The results are $\\nu=0.62$ for\nthe Flory exponent and $\\zeta=0.80$ for the roughness exponent. Finally we\ncomment on the importance that numerical tests may have to test these\npredictions."
    },
    {
        "anchor": "Breakdown of large-N reduction in the quenched Eguchi-Kawai model: We study the validity of the large-N equivalence between four-dimensional\nSU(N) lattice gauge theory and its momentum quenched version -- the Quenched\nEguchi-Kawai (QEK) model. We have found strong evidence that this equivalence\ndoes not hold in the weak-coupling regime (and thus in the continuum limit).\nThis is based on weak-coupling analytic arguments and Monto-Carlo simulations\nat intermediate couplings with 20 <= N <= 200. Since detailed expositions of\nour arguments, methods and results have already appeared in Phys. Rev.\nD78:034507 (2008) and Phys. Rev. D78:074503 (2008), we attempt here to give a\nmore intuitive explanation of our results. The breakdown of reduction that we\nfind is due to a dynamically generated correlation between different Euclidean\ncomponents of the gauge fields.",
        "positive": "On the discretization of physical momenta in lattice QCD: The adoption of two distinct boundary conditions for two fermions species on\na finite lattice allows to deal with arbitrary relative momentum between the\ntwo particle species, in spite of the momentum quantization rule due to a\nlimited physical box size. We test the physical significance of this\ntopological momentum by checking in the continuum limit the validity of the\nexpected energy-momentum dispersion relations."
    },
    {
        "anchor": "The Higgs mechanism on the lattice: The lattice regularization of the Higgs sector of the standard model is\nsummarized. The triviality bound and vacuum instability bound are described.\nThe question of chiral gauge theories is discussed. Some aspects of the\nnumerical simulations of the electroweak phase transition are considered.",
        "positive": "Heavy Quarks on the Lattice: This lecture describes the treatment of heavy quarks in lattice QCD by\nimplementing the Isgur-Wise limit. The method is briefly discussed, and some of\nthe special features of the resulting theory are highlighted. We emphasize\nissues of the renormalization of the effective theory. The formulation permits\na calculation of heavy quark processes even when the momentum transfers are\nmuch larger than the inverse lattice spacing. Applications include\nsemi-leptonic heavy quark decay and scattering processes, including the\ncomputation of the nonperturbative part of the Isgur-Wise universal function."
    },
    {
        "anchor": "Light quark masses from UKQCD's dynamical simulations with O(a)-improved\n  Wilson fermions: I present preliminary results on the light quark masses from a partially\nquenched analysis of UKQCD's dynamical datasets.",
        "positive": "More on the finite size mass shift formula for stable particles: The next to leading order (NLO) contribution of the generalized finite size\nmass shift formula for an interacting two stable particle system in a periodic\n$L^{3}$ box is discriminated with maintaining its model independent structure\nand validity to all orders in perturbation theory. The influence of the NLO\ncontribution is examined for the nucleon mass shift in the realistic\nnucleon-pion system."
    },
    {
        "anchor": "Lattice Gauge Theory and (Quasi)-Conformal Technicolor: QCD with 2 flavours of massless colour-sextet quarks is studied as a theory\nwhich might exhibit a range of scales over which the running coupling constant\nevolves very slowly (walks). We simulate lattice QCD with 2 flavours of sextet\nstaggered quarks to determine whether walks, or if it has an infrared fixed\npoint, making it a conformal field theory. Our initial simulations are\nperformed at finite temperatures $T=1/N_ta$ ($N_t=4$ and $N_t=6$), which allows\nus to identify the scales of confinement and chiral-symmetry breaking from the\ndeconfinement and chiral-symmetry restoring transitions. Unlike QCD with\nfundamental quarks, these two transitions appear to be well-separated. The\nchange in coupling constants at these transitions between the two different\ntemporal extents $N_t$, is consistent with these being finite temperature\ntransitions for an asymptotically free theory, which favours walking behaviour.\nIn the deconfined phase, the Wilson Line shows a 3-state signal. Between the\nconfinement and chiral transitions, there is an additional transition where the\nstates with Wilson Lines oriented in the directions of the complex cube roots\nof unity disorder into a state with a negative Wilson Line.",
        "positive": "Static quark-antiquark potential and Dirac eigenvector correlators: We represent the Polyakov loop correlator as a spectral sum of correlators of\neigenvectors of the lattice Dirac operator. This spectral representation is\nstudied numerically using quenched SU(3) configurations below and above the\ndeconfinement temperature. We analyze whether the individual Dirac eigenvector\ncorrelators differ in the confined and deconfined phases. The decay properties\nof the normalized Dirac eigenvector correlators turn out to be essentially\nidentical in the two phases, but the amplitudes change. This change of the\namplitudes shifts the relative contributions of the individual Dirac\neigenvector correlators and is the driving mechanism for the transition from\nthe confining static potential into the deconfining one."
    },
    {
        "anchor": "Hybrid configuration content of heavy S-wave mesons: We use the non-relativistic expansion of QCD (NRQCD) on the lattice to study\nthe lowest hybrid configuration contribution to the ground state of heavy\nS-wave mesons. Using lowest-order lattice NRQCD to create the heavy-quark\npropagators, we form a basis of ``unperturbed'' S-wave and hybrid states. We\nthen apply the lowest-order coupling of the quark spin and chromomagnetic field\nat an intermediate time slice to create ``mixed'' correlators between the\nS-wave and hybrid states. From the resulting amplitudes, we extract the\noff-diagonal element of our two-state Hamiltonian. Diagonalizing this\nHamiltonian gives us the admixture of hybrid configuration within the meson\nground state. The present effort represents a continuation of previous work:\nthe analysis has been extended to include lattices of varying spacings, source\noperators having better overlap with the ground states, and the pseudoscalar\n(along with the vector) channel. Results are presented for bottomonium\n($\\Upsilon$, $\\eta_b^{}$) using three different sets of quenched lattices. We\nalso show results for charmonium ($J/\\psi$, $\\eta_c^{}$) from one lattice set,\nalthough we note that the non-relativistic approximation is not expected to be\nvery good in this case.",
        "positive": "Scaled Affine Quantization of $\\varphi^4_4$ in the Low Temperature Limit: We prove through Monte Carlo analysis that the covariant euclidean scalar\nfield theory, $\\varphi^r_n$, where $r$ denotes the power of the interaction\nterm and $n = s + 1$ where $s$ is the spatial dimension and $1$ adds imaginary\ntime, such that $r = n = 4$ can be acceptably quantized using scaled affine\nquantization and the resulting theory is nontrivial and renormalizable even at\nlow temperatures in the highly quantum regime."
    },
    {
        "anchor": "Meson spectra from overlap fermion on domain wall gauge configurations: We report meson spectra obtained by using valence overlap fermion propagators\ngenerated on a background of 2+1 flavor domain wall fermion gauge\nconfigurations on 16^3 X 32, 24^3 X 64 and 32^3 X 64 lattices. We use\nmany-to-all correlators with Z3 grid source and low eigenmode substitution\nwhich is efficient in reducing errors for the hadron correlators. The\npreliminary results on meson spectrum, a0 correlators, and charmonium hyperfine\nsplitting for three sea quark masses are reported here.",
        "positive": "Duals of nonabelian gauge theories in $D$ dimensions: The dual of an arbitrary $D$-dimensional nonabelian lattice gauge theory,\nobtained after character expansion and integration over the gauge group, is\nshown to be a {\\em local} lattice theory in the eigenspace of the Casimir\noperators. For $D\\leq4$ we also provide the explicit form of the action as a\nproduct of character expansion coefficients and Racah coefficients. The\nrepresentation can be used to facilitate strong coupling expansions.\nFurthermore, the possibility of simulations, at weak coupling, in the dual\nrepresentation, is also discussed."
    },
    {
        "anchor": "Softening of First-Order Phase Transition on Quenched Random Gravity\n  Graphs: We perform extensive Monte Carlo simulations of the 10-state Potts model on\nquenched two-dimensional $\\Phi^3$ gravity graphs to study the effect of\nquenched coordination number randomness on the nature of the phase transition,\nwhich is strongly first order on regular lattices. The numerical data provides\nstrong evidence that, due to the quenched randomness, the discontinuous\nfirst-order phase transition of the pure model is softened to a continuous\ntransition, representing presumably a new universality class. This result is in\nstriking contrast to a recent Monte Carlo study of the 8-state Potts model on\ntwo-dimensional Poissonian random lattices of Voronoi/Delaunay type, where the\nphase transition clearly stayed of first order, but is in qualitative agreement\nwith results for quenched bond randomness on regular lattices. A precedent for\nsuch softening with connectivity disorder is known: in the 10-state Potts model\non annealed Phi3 gravity graphs a continuous transition is also observed.",
        "positive": "A Gauge-fixed Hamiltonian for Lattice QCD: We study the gauge fixing of lattice QCD in 2+1 dimensions, in the\nHamiltonian formulation. The technique easily generalizes to other theories and\ndimensions. The Hamiltonian is rewritten in terms of variables which are gauge\ninvariant except under a single global transformation. This paper extends\nprevious work, involving only pure gauge theories, to include matter fields."
    },
    {
        "anchor": "Quark mass and chiral condensate from the Wilson twisted mass lattice\n  quark propagator: In this work, we report about the determination of nonperturbative OPE\nparameters from fits of continuum perturbation theory to the Landau gauge quark\npropagator. The propagators are computed numerically using lattice QCD with\nNf=2 dynamical Wilson twisted mass fermions. We use four different values of\nthe lattice spacing ranging from about 0.1 fm to about 0.05 fm as well as\nseveral quark masses per lattice spacing. This allows us to obtain continuum\nresults for the chiral condensate and the average up/down quark mass. The main\nresults are the average up/down quark mass m_q = 3.0(4)(2) MeV at the physical\npoint and a value of the chiral condensate of -(299(26)(29) MeV)^3 in the\nchiral limit, both in the MSbar scheme at 2 GeV. We have also studied\nnonperturbative contaminations of our results at small values of the momenta,\nwhich are often interpreted as the contribution of the gluon condensate A^2. We\ndo see contributions from such terms, which are, however, not stable over the\norder in perturbation theory.",
        "positive": "The hadronic vacuum polarization with twisted boundary conditions: The leading-order hadronic contribution to the muon anomalous magnetic moment\nis given by a weighted integral over the subtracted hadronic vacuum\npolarization. This integral is dominated by euclidean momenta of order the muon\nmass, i.e., momenta not accessible on current lattice volumes with periodic\nboundary conditions. Twisted boundary conditions can in principle help in\naccessing momenta of any size even in a finite volume, but their use leads to a\nmodification of the Ward-Takahashi identity that normally guarantees\ntransversality of the vacuum polarization. As a result, the vacuum polarization\ncontains a non-transversal, quadratically divergent term, which arises as an\nartifact of using twisted boundary conditions in a finite volume. In this\narticle, we show how to determine and remove this term from the vacuum\npolarization."
    },
    {
        "anchor": "The Landshoff-Nachtmann Pomeron on the Lattice: We investigate the Landshoff-Nachtmann two-gluon-exchange model of the\nPomeron using gluon propagators computed in the Landau gauge within quenched\nlattice QCD calculations. We first determine an effective gluon-quark coupling\nby constraining the Pomeron-quark coupling to its phenomenological value\n$\\beta_0 = 2\\, \\gev^{-1}$. We then provide predictions for a variety of\ndiffractive processes. As the propagators have been evaluated entirely from QCD\nfirst principles (although in the quenched approximation), our results provide\na consistency check of the Landshoff-Nachtmann model. We address the issue of\nthe possible gauge-dependence of our results, which will be the object of a\nfuture study.",
        "positive": "High density QCD with static quarks: We study lattice QCD in the limit that the quark mass and chemical potential\nare simultaneously made large, resulting in a controllable density of quarks\nwhich do not move. This is similar in spirit to the quenched approximation for\nzero density QCD. In this approximation we find that the deconfinement\ntransition seen at zero density becomes a smooth crossover at any nonzero\ndensity, and that at low enough temperature chiral symmetry remains broken at\nall densities."
    },
    {
        "anchor": "A Heavy Higgs Particle in the TeV Mass Range ?: The first simulation results are presented on Higgs mass calculations in the\nspontaneously broken phase of the Higgs sector in the minimal Standard Model\nwith higher derivative regulator. A heavy Higgs particle is found in the TeV\nmass range in the presence of a complex conjugate ghost pair at higher\nenergies. The ghost pair evades easy experimental detection and a\nnonperturbative reinterpretation of the triviality Higgs mass bound becomes\nnecessary.",
        "positive": "Efficient implementation of the overlap operator on multi-GPUs: Lattice QCD calculations were one of the first applications to show the\npotential of GPUs in the area of high performance computing. Our interest is to\nfind ways to effectively use GPUs for lattice calculations using the overlap\noperator. The large memory footprint of these codes requires the use of\nmultiple GPUs in parallel. In this paper we show the methods we used to\nimplement this operator efficiently. We run our codes both on a GPU cluster and\na CPU cluster with similar interconnects. We find that to match performance the\nCPU cluster requires 20-30 times more CPU cores than GPUs."
    },
    {
        "anchor": "Un-screened forces in Quark-Gluon Plasma?: We study the correlator of temporal Wilson lines at non-zero temperature in\n2+1 flavor lattice QCD with the aim to define the heavy quark-antiquark\npotential at non-zero temperature. For temperatures $153~{\\rm MeV} \\leq T \\leq\n352~{\\rm MeV}$ the spectral representation of this correlator is consistent\nwith a broadened peak in the spectral function, position or width of which then\ndefines the real or imaginary parts of the heavy quark-antiquark potential at\nnon-zero temperature, respectively. We find that the real part of the potential\nis not screened contrary to the widely-held expectations. We comment on how\nthis fact may modify the picture of quarkonium melting in the quark-gluon\nplasma.",
        "positive": "The Effect of Reduced Spatial Symmetries on Lattice States: Results for\n  Non-zero Linear Momentum: The irreducible representations of the cubic space group are described and\nused to determine the mapping of continuum states to lattice states with\nnon-zero linear momentum. The Clebsch-Gordan decomposition is calculated from\nthe character table for the cubic space group. These results are used to\nidentify multiparticle states which appear in the hadron spectrum on the\nlattice."
    },
    {
        "anchor": "Dual Higgs Theory for Color Confinement in Quantum Chromodynamics: Based on the dual superconductor picture, we study the confinement phenomena\nsystematically, using the lattice QCD, the monopole-current dynamics and the\ndual Ginzburg-Landau (DGL) theory. (1) We study the origin of abelian dominance\nfor the confinement force in the maximally abelian (MA) gauge in terms of the\ngluon-field properties using the lattice QCD. In the MA gauge, the off-diagonal\ngluon amplitude is strongly suppressed, and the off-diagonal gluon phase tends\nto be random, according to the weakness of the constraint from the QCD action.\nWithin the random-variable approximation for the off-diagonal gluon phase, we\nshow the perimeter law of the off-diagonal gluon contribution to the Wilson\nloop, i.e. abelian dominance for the string tension, in the semi-analytical\nmanner. (2) We study the QCD-monopole structure in terms of the gluon field,\nusing the lattice QCD in the MA gauge. Around the monopole, both abelian and\noff-diagonal parts of the QCD action become large, however, due to the\ncancellation between them, monopoles can appear in QCD without large cost of\nthe QCD action. (3) We derive a simple relation between the confinement force\nand the monopole density by idealizing the monopole contribution to the Wilson\nloop. (4) We study the monopole current dynamics. (5) We consider the\nderivation of the DGL theory from the monopole ensemble. (6) We study the QCD\nphase transition at finite temperatures in the DGL theory. (7) We apply the DGL\ntheory for the hadron-bubble formation in early Universe and quark-gluon-plasma\nformation process in the ultra-relativistic heavy-ion collision.",
        "positive": "Pseudoscalar decay constants from N_f=2+1+1 twisted mass lattice QCD: We present first results for the pseudoscalar decay constants $f_K$, $f_D$\nand $f_{D_s}$ from lattice QCD with N_f=2+1+1 flavours of dynamical quarks. The\nlattice simulations have been performed by the European Twisted Mass\ncollaboration (ETMC) using maximally twisted mass quarks. For the pseudoscalar\ndecay constants we follow a mixed action approach by using so called\nOsterwalder-Seiler fermions in the valence sector for strange and charm quarks.\nThe data for two values of the lattice spacing and several values of the\nup/down quark mass is analysed using chiral perturbation theory."
    },
    {
        "anchor": "Vortex topology and the continuum limit of lattice gauge theories: We study the stability of Z_2 topological vortex excitations in d+1\ndimensional SU(2) Yang-Mills theory on the lattice at T=0. This is found to\ndepend on d and on the coupling considered. We discuss the connection with\nlattice artifacts causing bulk transitions in the beta_A-beta_F plane and draw\nsome conclusions regarding the continuum limit of the theory.",
        "positive": "Reweighting twisted boundary conditions: Imposing twisted boundary conditions on the fermionic fields is a procedure\nextensively used when evaluating, for example, form factors on the lattice.\nTwisting is usually performed for one flavour and only in the valence, and this\ncauses a breaking of unitarity. In this work we explore the possibility of\nrestoring unitarity through the reweighting method. We first study some\nproperties of the approach at tree level and then we stochastically evaluate\nratios of fermionic determinants for different boundary conditions in order to\ninclude them in the gauge averages, avoiding in this way the expensive\ngeneration of new configurations for each choice of the twisting angle,\n$\\theta$. As expected the effect of reweighting is negligible in the case of\nlarge volumes but it is important when the volumes are small and the twisting\nangles are large. In particular we find a measurable effect for the plaquette\nand the pion correlation function in the case of $\\theta=\\pi/2$ in a volume\n$16\\times 8^3$, and we observe a systematic upward shift in the pion dispersion\nrelation."
    },
    {
        "anchor": "Unquenched Studies Using the Truncated Determinant Algorithm: A truncated determinant algorithm is used to study the physical effects of\nthe quark eigenmodes associated with eigenvalues below 420 MeV. This initial\nhigh statistics study focuses on coarse ($6^4$) lattices (with O($a^2$)\nimproved gauge action), light internal quark masses and large physical volumes.\nThree features of full QCD are examined: topological charge distributions,\nstring breaking as observed in the static energy and the eta prime mass.",
        "positive": "Light hadrons from lattice QCD with light (u,d), strange and charm\n  dynamical quarks: We present results of lattice QCD simulations with mass-degenerate up and\ndown and mass-split strange and charm (N_f = 2+1+1) dynamical quarks using\nWilson twisted mass fermions at maximal twist. The tuning of the strange and\ncharm quark masses is performed at two values of the lattice spacing a~0.078 fm\nand a~0.086 fm with lattice sizes ranging from L~1.9 fm to L~2.8 fm. We measure\nwith high statistical precision the light pseudoscalar mass m_PS and decay\nconstant f_PS in a range 270 < m_PS < 510 MeV and determine the low energy\nparameters f_0, l_3 and l_4 of SU(2) chiral perturbation theory. We use the two\nvalues of the lattice spacing, several lattice sizes as well as different\nvalues of the light, strange and charm quark masses to explore the systematic\neffects. A first study of discretisation effects in light-quark observables and\na comparison to N_f=2 results are performed."
    },
    {
        "anchor": "SU(2) lattice gluon propagators at finite temperatures in the deep\n  infrared region and Gribov copy effects: We study numerically the SU(2) Landau gauge transverse and longitudinal gluon\npropagators at non-zero temperatures T both in confinement and deconfinement\nphases. The special attention is paid to the Gribov copy effects in the\nIR-region. Applying powerful gauge fixing algorithm we find that the Gribov\ncopy effects for the transverse propagator D_T(p) are very strong in the\ninfrared, while the longitudinal propagator D_L(p) shows very weak (if any)\nGribov copy dependence. The value D_T(0) tends to decrease with growing lattice\nsize; however, D_T(0) is non-zero in the infinite volume limit, in disagreement\nwith the suggestion made in [1]. We show that in the infrared region D_T(p) is\nnot consistent with the pole-type formula not only in the deconfinement phase\nbut also for T < T_c. We introduce new definition of the magnetic infrared mass\nscale ('magnetic screening mass') m_M. The electric mass m_E has been\ndetermined from the momentum space longitudinal gluon propagator. We study also\nthe (finite) volume and temperature dependence of the propagators as well as\ndiscretization errors.",
        "positive": "Heavy-light meson spectrum with and without NRQCD: Results for the spectrum of S and P-wave charmed mesons are obtained in the\nquenched approximation from a tadpole-improved anisotropic gauge field action\nand a D234 quark action. This is compared to the spectrum obtained from an\nNRQCD charm quark and a D234 light antiquark. NRQCD results for bottom mesons\nare also discussed."
    },
    {
        "anchor": "Wave functions of $SU(3)$ pure gauge glueballs on the lattice: The Bethe-Salpeter wave functions of $SU(3)$ pure gauge glueballs are\nrevisited in this study. The ground and the first excited states of scalar and\ntensor glueballs are identified unambiguously by using the variational method\non the basis of large operator sets. We calculate their wave functions in the\nCoulomb gauge and use two lattices with different lattice spacings to check the\ndiscretization artifacts. For ground states, the radial wave functions are\napproximately Gaussian and the size of the tensor is twice as large as that of\nthe scalar. For the first excited states, the radial nodes are clearly observed\nfor both the scalar and the tensor glueballs, such that they can be interpreted\nas the first radial excitations. These observations may shed light on the\ntheoretical understanding of the inner structure of glueballs.",
        "positive": "Mixing of S-Wave Charmonia with $\\mathrm{D}\\overline{\\mathrm{D}}$\n  Molecule States: Charmonium states can decay into pairs of $D$ and $\\overline{D}$ mesons if\ntheir masses are above the allowed decay thresholds. In general $c\\bar{c}$\nstates near threshold will also undergo mixing with $D\\overline{D}$ molecular\n(or tetraquark) states, by creation and annihilation of light quark-antiquark\npairs. The investigation of such effects sheds light on the higher Fock state\ncontributions to charmonium wavefunctions and on mass shifts, relative to a\nscenario where such mixing effects are neglected. A variational approach is\napplied to a mixing matrix between operators of both sectors, of $c\\bar{c}$ and\nof $D\\overline{D}$ molecular type. The efficient calculation of several\ndiagrams appearing in this matrix requires all-to-all propagators, which are\nrealized by sophisticated stochastic estimator techniques. The runs are\nperformed on $n_F=2$ $24^3\\times 48$ lattice volumes with $m_{\\pi} \\approx 280$\nMeV, using the non-perturbatively improved clover Wilson action, both for\nvalence and for sea quarks."
    },
    {
        "anchor": "Mesons in Transverse Lattice QCD at Strong Coupling and Large-N: Mesons in large-N QCD are analysed in light-front coordinates with a\ntransverse lattice at strong coupling. In this limit, their properties can be\nexpressed as simple renormalisations of the 't Hooft model results. The\nintegral eigenvalue equation for the mesons is derived. Spectrum, lightcone\nwavefunctions and form factors of various mesons can be numerically calculated\nfrom this equation.",
        "positive": "How To Fix Non-Perturbatively A Parameter Dependent Covariant Gauge On\n  The Lattice: We describe how to overcome some problems that usually prevent from obtaining\nan efficient algorithm to fix a generic covariant gauge on the lattice. This\ngauge is the lattice equivalent of the generic gauge usually adopted in\nperturbative calculations. It depends on a parameter whose value can be varied\nin order to check the gauge dependence of measured matrix elements."
    },
    {
        "anchor": "Advances in algorithms for solvers and gauge generation: I review recent research and advances in algorithms for solvers and gauge\ngeneration, with an emphasis on practical algorithms for four dimensional\nsimulations. Particular consideration is given to advances in multigrid\nsolvers, fourier acceleration and field transformation approaches to\naccelerating evolution dynamics, and to parallel tempering approaches to\nsolving the topological tunneling problem. Particular consideration is given to\nthe interaction between rapidly evolving computer architecture and optimal\nalgorithms that exploit these. In this conference, nascent machine learning\nalgorithms were separately reviewed",
        "positive": "Light Hadron Spectroscopy on Coarse Lattices with O(a^2) Mean-Field\n  Improved Actions: The masses and dispersions of light hadrons are calculated in lattice QCD\nusing an O(a^2) tadpole-improved gluon action and an O(a^2) tadpole-improved\nnext-nearest-neighbor fermion action originally proposed by Hamber and Wu. Two\nlattices of constant volume with lattice spacings of approximately 0.40 fm and\n0.24 fm are considered. The results reveal some scaling violations at the\ncoarser lattice spacing on the order of 5%. At the finer lattice spacing, the\ncalculated mass ratios reproduce state-of-the-art results using unimproved\nactions. Good dispersion and rotational invariance up to momenta of pa ~ 1 are\nalso found. The relative merit of alternative choices for improvement operators\nis assessed through close comparisons with other plaquette-based\ntadpole-improved actions."
    },
    {
        "anchor": "Testing gauge-invariant perturbation theory: Gauge-invariant perturbation theory for theories with a Brout-Englert-Higgs\neffect, as developed by Fr\\\"ohlich, Morchio and Strocchi, starts out from\nphysical, exactly gauge-invariant quantities as initial and final states. These\nare composite operators, and can thus be considered as bound states. In case of\nthe standard model, this reduces almost entirely to conventional perturbation\ntheory. This explains the success of conventional perturbation theory for the\nstandard model. However, this is due to the special structure of the standard\nmodel, and it is not guaranteed to be the case for other theories. Here, we\nreview gauge-invariant perturbation theory. Especially, we show how it can be\napplied and that it is little more complicated than conventional perturbation\ntheory, and that it is often possible to utilize existing results of\nconventional perturbation theory. Finally, we present tests of the predictions\nof gauge-invariant perturbation theory, using lattice gauge theory, in three\ndifferent settings. In one case, the results coincide with conventional\nperturbation theory and with the lattice results. In a second case, it appears\nthat the results of gauge-invariant perturbation theory agree with the lattice,\nbut differ from conventional perturbation theory. In the third case both\napproaches fail due to quantum fluctuations.",
        "positive": "Large $N$ scaling and factorization in SU($N$) Yang-Mills gauge theory: The large $N$ limit of SU($N$) gauge theories is well understood in\nperturbation theory. Also non-perturbative lattice studies have yielded\nimportant positive evidence that 't Hooft's predictions are valid. We go far\nbeyond the statistical and systematic precision of previous studies by making\nuse of the Yang-Mills gradient flow and detailed Monte Carlo simulations of\nSU($N$) pure gauge theories in 4 dimensions. With results for $N=3,4,5,6,8$ we\nstudy the limit and the approach to it. We pay particular attention to\nobservables which test the expected factorization in the large $N$ limit. The\ninvestigations are carried out both in the continuum limit and at finite\nlattice spacing. Large $N$ scaling is verified non-perturbatively and with high\nprecision; in particular, factorization is confirmed. For quantities which only\nprobe distances below the typical confinement length scale, the coefficients of\nthe $1/N$ expansion are of $\\mathrm{O}(1)$, but we found that large (smoothed)\nWilson loops have rather large $\\mathrm{O}(1/N^2)$ corrections. The exact size\nof such corrections does, of course, also depend on what is kept fixed when the\nlimit is taken."
    },
    {
        "anchor": "Hadronic light-by-light scattering contribution to the muon anomalous\n  magnetic moment from lattice QCD: The form factor that yields the light-by-light scattering contribution to the\nmuon anomalous magnetic moment is computed in lattice QCD+QED and QED. A\nnon-perturbative treatment of QED is used and is checked against perturbation\ntheory. The hadronic contribution is calculated for unphysical quark and muon\nmasses, and only the diagram with a single quark loop is computed.\nStatistically significant signals are obtained. Initial results appear\npromising, and the prospect for a complete calculation with physical masses and\ncontrolled errors is discussed.",
        "positive": "Relative scale setting for two-color QCD with Nf=2 Wilson fermions: We determine the scale setting function and the pseudo-critical temperature\non the lattice in $N_f=2$ two-color QCD using the Iwasaki gauge and Wilson\nfermion actions. Although two-color QCD does not correspond to the real world,\nit is very useful as a good testing ground for three-color QCD. The scale\nsetting function gives the relative lattice spacings of simulations performed\nat different values of the bare coupling. It is a necessary tool for taking the\ncontinuum limit. Firstly, we measure the meson spectra for various combinations\nof ($\\beta,\\kappa$) and find a line of constant physics in $\\beta$--$\\kappa$\nplane. Next, we determine the scale setting function via $w_0$ scale in the\ngradient flow method. Furthermore, we estimate the pseudo-critical temperature\nat zero chemical potential from the chiral susceptibility. Combining these\nresults, we can discuss the QCD phase diagram in which both axes are given by\ndimensionless quantities, namely, the temperature normalized by the\npseudo-critical temperature on the lattice and the chemical potential\nnormalized by the pseudoscalar meson mass. It makes it easy to compare among\nseveral lattice studies and also makes it possible to compare theoretical\nanalyses and lattice studies in the continuum limit."
    },
    {
        "anchor": "Free energies of static three quark systems: We study the behaviour of free energies of baryonic systems composed of three\nheavy quarks on the lattice in SU(3) pure gauge theory at finite temperature.\nFor all temperatures above $T_c$ we find that the connected part of the singlet\n(decuplet) free energy of the three quark system is given by the sum of the\nconnected parts of the free energies of $qq$-triplets (-sextets). Using\nrenormalized free energies we can compare free energies in different colour\nchannels as well as those of $qq$- and $qqq$-systems on an unique energy scale.",
        "positive": "Neutron Electric Dipole Moment with Domain Wall Quarks: We present preliminary results for nucleon dipole moments computed with\ndomain wall fermions. Our main target is the electric dipole moment of the\nneutron arising from the theta term in the gauge part of the QCD lagrangian.\nThe calculated magnetic dipole moments of the proton and neutron are in rough\naccord with experimental values."
    },
    {
        "anchor": "Hadrons in (1+1)D Hamiltonian hardcore lattice QCD: We study 2-flavor Hamiltonian lattice QCD in (1+1)D with hardcore gluons, at\nzero and finite density, by means of matrix product states. We introduce a\nformulation of the theory where gauge redundancy is absent and construct a\ngauge invariant tensor network ansatz. We show that the model is critical in an\nextended subregion of parameter space and identify at least two distinct\nphases, one of which embeds the continuum limit location. We reconstruct a\nsubset of the particle spectrum in each phase, identifying edge and bulk\ngapless modes. We thereby show that the studied model provides a minimal SU(3)\ngauge theory whilst reproducing known phenomena of (3+1)D QCD. Most notably, it\nfeatures charged pions.",
        "positive": "Precision lattice test of the gauge/gravity duality at large-$N$: We pioneer a systematic, large-scale lattice simulation of D0-brane quantum\nmechanics. The large-$N$ and continuum limits of the gauge theory are taken for\nthe first time at various temperatures $0.4 \\leq T \\leq 1.0$. As a way to\ndirectly test the gauge/gravity duality conjecture we compute the internal\nenergy of the black hole directly from the gauge theory and reproduce the\ncoefficient of the supergravity result $E/N^2=7.41T^{14/5}$. This is the first\nconfirmation of the supergravity prediction for the internal energy of a black\nhole at finite temperature coming directly from the dual gauge theory. We also\nconstrain stringy corrections to the internal energy."
    },
    {
        "anchor": "Charmed Strange mesons from Lattice QCD with Overlap Fermions: The charmed-strange meson masses are calculated on a quenched lattice QCD.\nThe charm and strange quark propagators are calculated on the same lattice with\nthe overlap fermion. $16^3\\times 72$ lattice with Wilson gauge action at\n$\\beta=0.6345$ are used. The charm and strange quark masses are determined by\nfitting the $J/\\psi$ and $\\phi$ masses respectively. The charmed strange meson\nspectrum for the scalar, axial, pseudoscalar and vector channels are\ncalculated. They agree with experiments. In particular, we find the scalar\nmeson mass to be 2248(78)MeV which is in agreement with that of D_{s0}^*(2317).",
        "positive": "Large $N_c$ scaling of meson masses and decay constants: We perform an $\\textit{ab initio}$ calculation of the $N_c$ scaling of the\nlow-energy couplings of the chiral Lagrangian of low-energy strong\ninteractions, extracted from the mass dependence of meson masses and decay\nconstants. We compute these observables on the lattice with four degenerate\nfermions, $N_f=4$, and varying number of colours, $N_c=3-6$, at a lattice\nspacing of $a\\simeq 0.075$ fm. We find good agreement with the expected $N_c$\nscaling and measure the coefficients of the leading and subleading terms in the\nlarge $N_c$ expansion. From the subleading $N_c$ corrections, we can also infer\nthe $N_f$ dependence, that we use to extract the value of the low-energy\ncouplings for different values of $N_f$. We find agreement with previous\ndeterminations at $N_c=3$ and $N_f=2, 3$ and also, our results support a strong\nparamagnetic suppression of the chiral condensate in moving from $N_f=2$ to\n$N_f=3$."
    },
    {
        "anchor": "Lattice Gluon Propagator in the Landau Gauge: A Study Using Anisotropic\n  Lattices: Lattice gluon propagators are studied using tadpole and Symanzik improved\ngauge action in Landau gauge. The study is performed using anisotropic lattices\nwith asymmetric volumes. The Landau gauge dressing function for the gluon\npropagator measured on the lattice is fitted according to a leading power\nbehavior: $Z(q^2)\\simeq (q^2)^{2\\kappa}$ with an exponent $\\kappa$ at small\nmomenta. The gluon propagators are also fitted using other models and the\nresults are compared. Our result is compatible with a finite gluon propagator\nat zero momentum in Landau gauge.",
        "positive": "Euclidean lattice simulation for the dynamical supersymmetry breaking: The global supersymmetry is spontaneously broken if and only if the\nground-state energy is strictly positive. We propose to use this fact to\nobserve the spontaneous supersymmetry breaking in euclidean lattice\nsimulations. For lattice formulations that possess a manifest fermionic\nsymmetry, there exists a natural choice of a hamiltonian operator that is\nconsistent with a topological property of the Witten index. We confirm validity\nof our idea in models of the supersymmetric quantum mechanics. We then examine\na possibility of a dynamical supersymmetry breaking in the two-dimensional\n$\\mathcal{N}=(2,2)$ super Yang-Mills theory with the gauge group $\\SU(2)$, for\nwhich the Witten index is unknown. Differently from a recent conjectural claim,\nour numerical result tempts us to conclude that supersymmetry is not\nspontaneously broken in this system."
    },
    {
        "anchor": "The Effect of Dynamical Gauge Field on the Chiral Fermion on a boundary: We study the effect of dynamical gauge field on the Kaplan's chiral fermion\non a boundary in the strong gauge coupling limit in the extra dimension. To all\norders of the hopping parameter expansion, we prove exact parity invariance of\nthe fermion propagator on the boundary. This means that the chiral property of\nthe boundary fermion, which seems to survive even in the presence of the gauge\nfield from a perturbative point of view, is completely destroyed by the\ndynamics of the gauge field.",
        "positive": "On calculating disconnected-type hadronic light-by-light scattering\n  diagrams from lattice QCD: For reliable comparison of the standard model prediction to the muon g-2 with\nits experimental value, the hadronic light-by-light scattering (HLbL)\ncontribution must be calculated by lattice QCD simulation. HLbL contribution\nhas many types of disconnected-type diagrams. Here, we start with recalling the\npoint that must be taken care of in every method to calculate them by lattice\nQCD, and present one concrete method called nonperturbative QED method."
    },
    {
        "anchor": "Approaching the conformal WZW behavior in the infrared limit of\n  two-dimensional massless QCD: a lattice study: Two-dimensional QCD with $N_c$ colors and $N_f$ flavors of massless fermions\nin the fundamental representation is expected to exhibit conformal behavior in\nthe infrared governed by a $u(N_f)$ WZW model with level $N_c$. Using numerical\nanalysis within the lattice formalism with exactly massless overlap fermions,\nwe show the emergence of such behavior in the infrared limit. Both the\ncontinuum extrapolated low-lying eigenvalues of the massless Dirac operator and\nthe propagator of scalar mesons exhibit a flow from the ultraviolet to the\ninfrared. We find that the amplitude of the conserved current correlator\nremains invariant under the flow, while the amplitude of the scalar correlator\napproaches $N_f$-independent values in the infrared.",
        "positive": "Constraining the hadronic spectrum through QCD thermodynamics on the\n  lattice: Fluctuations of conserved charges allow to study the chemical composition of\nhadronic matter. A comparison between lattice simulations and the Hadron\nResonance Gas (HRG) model suggested the existence of missing strange\nresonances. To clarify this issue we calculate the partial pressures of mesons\nand baryons with different strangeness quantum numbers using lattice\nsimulations in the confined phase of QCD. In order to make this calculation\nfeasible, we perform simulations at imaginary strangeness chemical potentials.\nWe systematically study the effect of different hadronic spectra on\nthermodynamic observables in the HRG model and compare to lattice QCD results.\nWe show that, for each hadronic sector, the well established states are not\nenough in order to have agreement with the lattice results. Additional states,\neither listed in the Particle Data Group booklet (PDG) but not well\nestablished, or predicted by the Quark Model (QM), are necessary in order to\nreproduce the lattice data. For mesons, it appears that the PDG and the quark\nmodel do not list enough strange mesons, or that, in this sector, interactions\nbeyond those included in the HRG model are needed to reproduce the lattice QCD\nresults."
    },
    {
        "anchor": "Monte Carlo simulations of the NJL model near the nonzero temperature\n  phase transition: We present results from numerical simulations of the Nambu-Jona-Lasinio model\nwith an SU(2)xSU(2) chiral symmetry and N_c=4,8, and 16 quark colors at nonzero\ntemperature. We performed the simulations by utilizing the hybrid Monte Carlo\nand hybrid Molecular Dynamics algorithms. We show that the model undergoes a\nsecond order phase transition. The critical exponents measured are consistent\nwith the classical 3d O(4) universality class and hence in accordance with the\ndimensional reduction scenario. We also show that the Ginzburg region is\nsuppressed by a factor of 1/N_c in accordance with previous analytical\npredictions.",
        "positive": "Nonperturbative investigations of SU(3) gauge theory with eight\n  dynamical flavors: We present our lattice studies of SU(3) gauge theory with $N_f$ = 8\ndegenerate fermions in the fundamental representation. Using nHYP-smeared\nstaggered fermions we study finite-temperature transitions on lattice volumes\nas large as $L^3 \\times N_t = 48^3 \\times 24$, and the zero-temperature\ncomposite spectrum on lattice volumes up to $64^3 \\times 128$. The spectrum\nindirectly indicates spontaneous chiral symmetry breaking, but\nfinite-temperature transitions with fixed $N_t \\leq 24$ enter a strongly\ncoupled lattice phase as the fermion mass decreases, which prevents a direct\nconfirmation of spontaneous chiral symmetry breaking in the chiral limit. In\naddition to the connected spectrum we focus on the lightest flavor-singlet\nscalar particle. We find it to be degenerate with the pseudo-Goldstone states\ndown to the lightest masses reached so far by non-perturbative lattice\ncalculations. Using the same lattice approach, we study the behavior of the\ncomposite spectrum when the number of light fermions is changed from eight to\nfour. A heavy flavor-singlet scalar in the 4-flavor theory affirms the contrast\nbetween QCD-like dynamics and the low-energy behavior of the 8-flavor theory."
    },
    {
        "anchor": "Testing MEM with Diquark and thermal Meson Correlation Functions: When applying the maximum entropy method (MEM) to the analysis of hadron\ncorrelation functions in QCD a central issue is to understand to what extent\nthis method can distinguish bound states, resonances and continuum\ncontributions to spectral functions. We discuss these issues by analyzing meson\nand diquark correlation functions at zero temperature as well as free quark\nanti-quark correlators. The latter test the applicability of MEM to high\ntemperature QCD.",
        "positive": "Light quark masses and pseudoscalar decay constants from Nf=2 Lattice\n  QCD with twisted mass fermions: We present the results of a lattice QCD calculation of the average up-down\nand strange quark masses and of the light meson pseudoscalar decay constants\nwith Nf=2 dynamical fermions. The simulation is carried out at a single value\nof the lattice spacing with the twisted mass fermionic action at maximal twist,\nwhich guarantees automatic O(a)-improvement of the physical quantities. Quark\nmasses are renormalized by implementing the non-perturbative RI-MOM\nrenormalization procedure. Our results for the light quark masses are\nm_ud^{msbar}(2 GeV)= 3.85 +- 0.12 +- 0.40 MeV, m_s^{msbar}(2 GeV) = 105 +- 3 +-\n9 MeV and m_s/m_ud = 27.3 +- 0.3 +- 1.2. We also obtain fK = 161.7 +- 1.2 +-\n3.1 MeV and the ratio fK/fpi=1.227 +- 0.009 +- 0.024. From this ratio, by using\nthe experimental determination of Gamma(K-> mu nu (gamma))/Gamma(pi -> mu nu\n(gamma)) and the average value of |Vud| from nuclear beta decays, we obtain\n|Vus|=0.2192(5)(45), in agreement with the determination from Kl3 decays and\nthe unitarity constraint."
    },
    {
        "anchor": "Theoretical and practical progresses in the HAL QCD method: In this report, we discuss some theoretical and practical progresses in the\nHAL QCD potential method. We first clarify the issue of the derivative\nexpansion for the non-local potential in the HAL QCD method. As the non-local\npotential in the original literature is not uniquely defined, we propose a\nprocedure to define a non-local potential from NBS wave functions in terms of\nthe derivative expansion. We then demonstrate how this definition works by\nusing quantum mechanics with a separable potential. Secondly we discuss an\nissue of Hermiticity of the HAL QCD potential. Since the NBS wav functions are\nnot orthogonal to each other in general, the HAL QCD potential is necessary to\nbe non-Hermitian. We consider the next-to-leading order potential, which can be\nmade Hermitian exactly by the change of variables. In general we can also make\nthe higher order HAL QCD potential Hermitian order by order in the derivative\nexpansion. An explicit example on how the procedure works is given for lattice\nQCD calculations. Finally we discuss how we can extract the HAL QCD potential\nfrom the NBS wave function in the boosted system. An explicit formula for this\nis derived.",
        "positive": "Moment Analysis of Hadronic Vacuum Polarization - Proposal for a lattice\n  QCD evaluation of $g_\u03bc-2$: I suggest a new approach to the determination of the hadronic vacuum\npolarization (HVP) contribution to the anomalous magnetic moment of the muon\n$a_{\\mu}^{\\rm HVP}$ in lattice QCD. It is based on properties of the Mellin\ntransform of the hadronic spectral function and their relation to the HVP self\nenergy in the Euclidean. I show how $a_{\\mu}^{\\rm HVP}$ is very well\napproximated by a few moments associated to this Mellin transform and how these\nmoments can be evaluated in lattice QCD, providing thus a series of tests when\ncompared with the corresponding determinations using experimental data."
    },
    {
        "anchor": "Fermionic boundary conditions and the finite temperature transition of\n  QCD: Finite temperature lattice QCD is probed by varying the temporal boundary\nconditions of the fermions. We develop the emerging physical behavior in a\nstudy of the quenched case and subsequently present first results for a fully\ndynamical calculation comparing ensembles below and above the phase transition.\nWe show that for low temperature spectral quantities of the Dirac operator are\ninsensitive to boundary conditions, while in the deconfined phase a non-trivial\nresponse to a variation of the boundary conditions sets in.",
        "positive": "K^0-\\bar{K}^0 mixing in the Standard Model from Nf=2+1+1 Twisted Mass\n  Lattice QCD: We present preliminary results at {\\beta} = 1.95 (a = 0.077 fm) on the first\nunquenched N_f=2+1+1 lattice computation of the B_K parameter which controls\nthe neutral kaon oscillations in the Standard Model. Using N_f=2+1+1 maximally\ntwisted sea quarks and Osterwalder-Seiler valence quarks we achieve O(a)\nimprovement and a continuum-like renormalization pattern for the four-fermion\noperator. Our results are extrapolated/interpolated to the physical\nlight/strange quark mass but not yet to the continuum limit. The computation of\nthe relevant renormalization constants is performed non perturbatively in the\nRI'-MOM scheme using dedicated simulations with N_f=4 degenerate sea quark\nflavours produced by the ETM collaboration.\n  We get B_K^{RGI} (a = 0.077) = 0.747(18), which when compared to our previous\nunquenched N_f=2 determination and most of the existing results, suggests a\nrather weak B_K^{RGI} dependence on the number of dynamical flavours. We are at\nthe moment analysing lattice data at two additional {\\beta} values which will\nallow us to perform an extrapolation to the continuum limit."
    },
    {
        "anchor": "Running alpha(s) from Landau-gauge gluon and ghost correlations: We estimate the running coupling constant of the strong interactions within\nthe nonperturbative framework of lattice QCD in Landau gauge. Our calculation\nis based on the ghost-gluon vertex which in the particular case of Landau gauge\nallows for a definition of alpha(s) in a MOM scheme solely in terms of the\ngluon and ghost dressing functions. As a first step we investigate the zero and\ntwo-flavour case and report here on preliminary results.",
        "positive": "$K\u03c0$ scattering and excited meson spectroscopy using the stochastic\n  LapH method: Elastic $I=1/2$, $s$- and $p$-wave $K\\pi$ scattering amplitudes are\nsimultaneously calculated using a L\\\"uscher style analysis on a single ensemble\nof dynamical Wilson-clover fermions at $m_\\pi \\sim 230$ MeV. Partial wave\nmixing due to the reduced rotational symmetries of the finite volume is\nincluded up to $\\ell=2$. We also present finite-volume QCD spectra on two large\nanisotropic lattices ($32^3 \\times 256$, $24^3 \\times 128$) with $m_\\pi \\sim\n230,\\ 390$ MeV respectively. In each symmetry channel, a large basis of one-\nand two-hadron interpolating operators is employed with all-to-all quark\npropagation treated using the stochastic LapH method."
    },
    {
        "anchor": "Nonperturbative investigation of the diquark potential: We perform an investigation of the static quark-quark-potential both in the\nconfined and the deconfined phase. We discuss conceptual and technical problems\nand present first results of an exploratory numerical investigation.",
        "positive": "Sunset integrals at finite volume: Chiral Perturbation Theory is a useful tool to aid in performing the various\nextrapolations needed in lattice QCD calculations of physical quantities. These\ninclude extrapolations in quark mass, finite lattice spacing and finite size of\nthe lattice. Especially the latter will become more important when the quark\nmasses on the lattice become smaller.\n  Here we develop the needed two-loop integrals at finite volume to do the\ncalculations for masses and decay constants for all general mass cases.\n  I will present results based on an expansion in Bessel functions as well as\non a version using theta functions and compare their efficiency. Work is in\nprogress to combine these results with two-loop ChPT calculations."
    },
    {
        "anchor": "Parity anomaly cancellation in a three-dimensional QED with single\n  massless Dirac fermion: We study a three-dimensional non-compact QED with a single two-component\nmassless fermion and two infinitely massive regulator fermions of half the\ncharge using lattice overlap formalism. The parity anomaly is expected to\ncancel exactly between the massless and regulator fermions in the continuum,\nbut this cancellation is inexact on lattice akin to lattice chiral gauge\ntheories. We show non-perturbatively that parity-breaking terms vanish in the\ncontinuum limit at any finite volume. We present numerical evidences that the\nresulting parity-invariant theory spontaneously breaks parity in the infinite\nvolume limit.",
        "positive": "Exotic Particles and $w_\\infty$-Algebras in Two- and High-Dimensional\n  Spaces: We construct a set of noncommuting translation operators in two and\nhigh-dimensional lattices. The algebras they close are $w_{\\infty}$-algebras.\nThe construction is based on the introduction of noncommmuting elementary link\noperators which link two neighborhood sites in the lattice. This kind of\noperators preserve the braiding nature of exotic particles living basically in\ntwo-dimensional space."
    },
    {
        "anchor": "The electromagnetic form factor of the pion in two-flavour lattice QCD: We present the current status of our lattice calculation of the\nelectromagnetic form factor of the pion with two flavours of non-perturbatively\nO(a)-improved Wilson fermions. Using twisted boundary conditions and stochastic\nsources we obtain accurate results with a fine momentum resolution near\n$q^2=0$. This enables the computation of the charge radius without model\ndependence. The ensembles cover various lattice spacings and pion masses,\nranging down to 250 MeV. This allows to compare the data to continuum chiral\nperturbation theory to NNLO including corrections of finite lattice spacing to\nperform a simultaneous chiral and continuum extrapolation. An estimate for the\nsystematic error resulting from the extrapolation can be obtained by looking at\nthe spread of results obtained from other functional forms such as polynomials.",
        "positive": "Lattice Perturbation Theory: Sources of uncertainties in perturbative calculations, tadpole improvement\nand its role in lattice perturbation theory, and six recent calculations are\ndiscussed."
    },
    {
        "anchor": "Is the Quenched Spectrum in agreement with Experiment?: We analyse the meson spectrum in quenched QCD using lattice gauge theory. By\nstudying hadron propagation with a variety of operators (both smeared and\nlocal), we are able to extract the ground state and first excited state masses\nwith confidence. We pay attention to the correlations among the data used in\nthe fits to extract these masses and couplings. We compare the resulting hadron\nspectrum with experiment and find evidence for a significant departure in the\npseudoscalar and vector meson masses.",
        "positive": "Topological properties of the SU(3) random vortex world-surface model: The random vortex world-surface model is an infrared effective model of\nYang-Mills dynamics based on center vortex degrees of freedom. These degrees of\nfreedom carry topological charge through writhe and self-intersection of their\nworld-surfaces. A practical implementation of the model realizes the vortex\nworld-surfaces by composing them of elementary squares on a hypercubic lattice.\nThe topological charge for specifically such configurations is constructed in\nthe case of SU(3) color. This necessitates a proper treatment of vortex color\nstructure at vortex branchings, a feature which is absent in the SU(2) color\ncase investigated previously. On the basis of the construction, the topological\nsusceptibility is evaluated in the random vortex world-surface ensemble, both\nin the confined low-temperature as well as in the deconfined high-temperature\nphase."
    },
    {
        "anchor": "Multigrid approach in shifted linear systems for the non-degenerated\n  twisted mass operator: Application of multigrid solvers in shifted linear systems is studied. We\nfocus on accelerating the rational approximation needed for simulating single\nflavor operators. This is particularly useful, in the case of twisted mass\nfermions for mass non-degenerate quarks and can be employed to accelerate the\n$N_f=1+1$ sector of $N_f=2+1+1$ twisted mass fermion simulations. The multigrid\nsolver is accelerated by employing suitable initial guesses. We propose a novel\nstrategy for proposing initial guesses for shifted linear systems based on the\nLagrangian interpolation of the previous solutions.",
        "positive": "Compact QED under scrutiny: it's first order: We report new results from our finite size scaling analysis of 4d compact\npure U(1) gauge theory with Wilson action. Investigating several cumulants of\nthe plaquette energy within the Borgs-Kotecky finite size scaling scheme we\nfind strong evidence for a first-order phase transition and present a high\nprecision value for the critical coupling in the thermodynamic limit."
    },
    {
        "anchor": "Entanglement entropy in lattice gauge theories: We report on the recent progress in theoretical and numerical studies of\nentanglement entropy in lattice gauge theories. It is shown that the concept of\nquantum entanglement between gauge fields in two complementary regions of space\ncan only be introduced if the Hilbert space of physical states is extended in a\ncertain way. In the extended Hilbert space, the entanglement entropy can be\npartially interpreted as the classical Shannon entropy of the flux of the gauge\nfields through the boundary between the two regions. Such an extension leads to\na reduction procedure which can be easily implemented in lattice simulations by\nconstructing lattices with special topology. This enables us to measure the\nentanglement entropy in lattice Monte-Carlo simulations. On the simplest\nexample of Z2 lattice gauge theory in (2 + 1) dimensions we demonstrate the\nrelation between entanglement entropy and the classical entropy of the field\nflux. For SU(2) lattice gauge theory in four dimensions, we find a signature of\nnon-analytic dependence of the entanglement entropy on the size of the region.\nWe also comment on the holographic interpretation of the entanglement entropy.",
        "positive": "Finite volume effects and quark mass dependence of the N(1535) and\n  N(1650): For resonances decaying in a finite volume, the simple identification of\nstate and eigenvalue is lost. The extraction of the scattering amplitude is a\nmajor challenge as we demonstrate by extrapolating the physical S_{11}\namplitude of pion-nucleon scattering to the finite volume and unphysical quark\nmasses, using a unitarized chiral framework including all next-to-leading order\ncontact terms. We show that the pole movement of the resonances N(1535)1/2^-\nand N(1650)1/2^- with varying quark masses is non-trivial. In addition, there\nare several strongly coupled S-wave thresholds that induce a similar avoided\nlevel crossing as narrow resonances. The level spectrum is predicted for two\ntypical lattice setups, and ways to extract the amplitude from upcoming lattice\ndata are discussed."
    },
    {
        "anchor": "Fluctuations and Higher Moments of Conserved Charges from the Lattice: We present results for the lowest-order non-vanishing quark number\nsusceptibilities. These were calculated using an improved action viz. the HISQ\naction, which controls taste violations that are responsible for distorting the\nlight meson spectrum. Our calculations, with a pion mass of 160 MeV, are also\nmuch closer to the physical limit than previous studies. We find a broad\ncrossover from the hadronic to the quark regimes, although interactions remain\nsignificant even at the highest temperatures studied. Our results are also in\ngood agreement with Hadron Resonance Gas models below the crossover\ntemperature.",
        "positive": "Heavy $qq$ interaction at finite temperature: The first lattice QCD numerical study of heavy quark-quark potentials at\nfinite temperature is reported. Using the quenched approximation, we evaluate\nthe color anti-symmetric and symmetric potentials."
    },
    {
        "anchor": "Polarized Nucleon Structure Functions from Lattice QCD: We describe a high statistics quenched QCD calculation of the moments of the\npolarized deep-inelastic structure functions g_1 and g_2 of the proton and\nneutron.",
        "positive": "QCD transition at the physical point, and its scaling window from\n  twisted mass Wilson fermions: We study the scaling properties of the finite temperature QCD phase\ntransition, for light quark masses ranging from the heavy quark regime to their\nphysical values. The lattice results are obtained in the fixed scale approach\nfrom simulations of $N_f=2+1+1$ flavours of Wilson fermions at maximal twist.\nWe identify an order parameter free from the the linear contributions in mass\ndue to additive renormalization and regular terms in the Equation of State,\nwhich proves useful for the assessment of the hypothesized universal behaviour.\nWe find compatibility with the 3D $O(4)$ universality class for the physical\npion mass and temperatures $120$ MeV $ \\lesssim T \\lesssim 300$ MeV. We discuss\nviolation of scaling at larger masses and a possible cross-over to mean field\nbehaviour. The chiral extrapolation $T_0 = 134^{+6}_{-4}$ MeV of the\npseudocritical temperature is robust against predictions of different\nuniversality classes and consistent with its estimate from the $O(4)$ Equation\nof State for the physical pion mass."
    },
    {
        "anchor": "$B$-meson semileptonic decays with highly improved staggered quarks: We present an update of the Fermilab Lattice and MILC Collaborations project\nto compute the form factors for semileptonic $B_{(s)}$-meson decays. Our\ncalculation uses the highly improved staggered quark (HISQ) action for sea and\nvalence quarks, and ensembles with up, down, strange, and charm quarks in the\nsea. Using a highly improved action with the MILC Collaboration's gauge\nensembles with lattice spacings down to $a\\approx0.03$ fm, allows the heavy\nvalence quarks to be treated with the same discretization as the light and\nstrange quarks. This unified treatment of the valence quarks allows for\nabsolutely normalized vector currents, bypassing the need for perturbative\nmatching, which has been a source of uncertainty in previous calculations of\n$B$-meson decay form factors by our collaboration. All preliminary form-factor\nresults are blinded.",
        "positive": "Minimally Doubled Fermion Revival: In this paper, we present the recent progress on minimally doubled lattice\nactions. In particular, we discuss the proposal of Creutz and its variations on\nan orthogonal lattice. A preliminary computation of the pion mass on an SU(3)\nbackground field shows the expected behaviour as predicted form the chiral\nperturbation theory."
    },
    {
        "anchor": "Phenomenological Equations of State for SU(N) Gauge Theories: Two phenomenological models describing an SU(N) gluon plasma are presented\nusing the eigenvalues of the Polyakov loop as the order parameters of the\ndeconfinement transition. Each model has a single free parameter and exhibits\nbehavior similar to lattice simulations over the range T_d-5T_d. The N=2\ndeconfinement transition is second order in both models, while N=3,4, and 5 are\nfirst order. Both models appear to have a smooth large-N limit. The confined\nphase is characterized by a mutual repulsion of Polyakov loop eigenvalues that\nmakes the Polyakov loop expectation value zero. The motion of the eigenvalues\nis responsible for the approach to the blackbody limit over the range T_d-5T_d.",
        "positive": "Distributing the chiral and flavour components of Dirac-Kahler fermions\n  across multiple lattices: We use a specific implementation of discrete differential geometry to\ndescribe Dirac-Kahler fermions in such a way that we can separate their chiral\nand flavour components. The formulation introduces additional lattices so that\non each lattice there is a single field of definate chirality. Within this\nframework, we define an non-compact Abelian gauge theory."
    },
    {
        "anchor": "Nucleon Charges from 2+1+1-flavor HISQ and 2+1-flavor clover lattices: Precise estimates of the nucleon charges $g_A$, $g_S$ and $g_T$ are needed in\nmany phenomenological analyses of SM and BSM physics. In this talk, we present\nresults from two sets of calculations using clover fermions on 9 ensembles of\n2+1+1-flavor HISQ and 4 ensembles of 2+1-flavor clover lattices. We show that\nhigh statistics can be obtained cost-effectively using the truncated solver\nmethod with bias correction and the coherent source sequential propagator\ntechnique. By performing simulations at 4--5 values of the source-sink\nseparation $t_{\\rm sep}$, we demonstrate control over excited-state\ncontamination using 2- and 3-state fits. Using the high-precision 2+1+1-flavor\ndata, we perform a simultaneous fit in $a$, $M_\\pi$ and $M_\\pi L$ to obtain our\nfinal results for the charges.",
        "positive": "Towards a strong-coupling theory of QCD at finite density: We apply strong-coupling perturbation theory to the QCD lattice Hamiltonian.\nWe begin with naive, nearest-neighbor fermions and subsequently break the\ndoubling symmetry with next-nearest-neighbor terms. The effective Hamiltonian\nis that of an antiferromagnet with an added kinetic term for baryonic\n\"impurities,\" reminiscent of the t-J model of high-T_c superconductivity. As a\nfirst step, we fix the locations of the baryons and make them static. Following\nanalyses of the t-J model, we apply large-N methods to obtain a phase diagram\nin the (N_c,N_f) plane at zero temperature and baryon density. Next we study a\nsimplified U(3) toy model, in which we add baryons to the vacuum. We use a\ncoherent state formalism to write a path integral which we analyze with mean\nfield theory, obtaining a phase diagram in the (n_B,T) plane."
    },
    {
        "anchor": "Existence of positive representations for complex weights: The necessity of computing integrals with complex weights over manifolds with\na large number of dimensions, e.g., in some field theoretical settings, poses a\nproblem for the use of Monte Carlo techniques. Here it is shown that very\ngeneral complex weight functions P(x) on R^d can be represented by real and\npositive weights p(z) on C^d, in the sense that for any observable f, <f(x)>_P\n= <f(z)>_p, f(z) being the analytical extension of f(x). The construction is\nextended to arbitrary compact Lie groups.",
        "positive": "Numerical simulation tests with light dynamical quarks: Two degenerate flavours of quarks are simulated with small masses down to\nabout one fifth of the strange quark mass by using the two-step multi-boson\n(TSMB) algorithm. The lattice size is 8^3 x 16 with lattice spacing about\n0.27fm which is not far from the N_t=4 thermodynamical cross-over line.\nAutocorrelations of different physical quantities are estimated as a function\nof the quark mass. The eigenvalue spectra of the Wilson-Dirac operator are\ninvestigated."
    },
    {
        "anchor": "Connection between centre vortices and instantons through gauge-field\n  smoothing: A recent lattice study of the Landau-gauge overlap quark propagator has shown\na connection between centre vortices and dynamical chiral symmetry breaking in\n$\\mathrm{SU}(3)$ gauge theory. We further investigate this relationship through\nan exploration of the connection to the instanton degrees of freedom. After\nidentifying centre vortices on the lattice in maximal centre gauge, we smooth\nconfigurations using multiple algorithms. We are able to create an instanton\nliquid-like background on configurations consisting solely of centre vortices,\nanalogous to that found on Monte-carlo generated configurations after similar\nsmoothing. Through calculations of the static quark potential and Landau-gauge\noverlap propagator, we show that this background is able to reproduce all\nsalient long-range features of the original configurations. Thus we conclude\nthat the information necessary to recreate the long-range structure of\n$\\mathrm{SU}(3)$ gauge theory is contained within the centre vortex degrees of\nfreedom.",
        "positive": "The QCD Phase Diagram with Effective Theories: We study two effective theories for QCD at non-zero temperature and finite\nchemical potential, using local Polyakov loops as the degrees of freedom. The\nsign problem is solved by exactly mapping the partition function to a sum over\nflux and monomer variables with only real and positive weights, making the two\nmodels accessible to Monte Carlo simulation techniques. We use generalized worm\nalgorithms and a local Metropolis update to perform the simulations and\ndetermine the phase diagram as a function of the temperature and the chemical\npotential."
    },
    {
        "anchor": "Numerical investigations of the Schwinger model and selected quantum\n  spin models: Numerical investigations of the XY model, the Heisenberg model and the J-J'\nHeisenberg model are conducted, using the exact diagonalisation, the numerical\nrenormalisation and the density matrix renormalisation group approach. The\nlow-lying energy levels are obtained and finite size scaling is performed to\nestimate the bulk limit values. The results are found to be consistent with the\nexact values. The DMRG results are found to be most promising.\n  The Schwinger model is also studied using the exact diagonalisation and the\nstrong coupling expansion. The massless, the massive model and the model with a\nbackground electric field are explored. Ground state energy, scalar and vector\nparticle masses and order parameters are examined. The achieved values are\nobserved to be consistent with previous results and theoretical predictions.\nPath to the future studies is outlined.",
        "positive": "Porting DDalphaAMG solver to K computer: We port Domain-Decomposed-alpha-AMG solver to the K computer. The system has\n8 cores and 16 GB memory per node, of which theoretical peak is 128 GFlops\n(82,944 nodes in total). Its feature, as many as 256 registers per core and as\nlarge as 0.5 byte/Flop ratio, requires a different tuning from other machines.\nIn order to use more registers, we change some of the data structure and\nrewrite matrix-vector operations with intrinsics. The performance is improved\nby more than a factor two for twelve solves including the setup. The efficiency\nis still about 5% after the optimization, which is lower than a previously\ntuned mixed precision solver for the K computer, 22%. The throughput is,\nhowever, more than two times better for a physical point configuration."
    },
    {
        "anchor": "The overlap is not a waveguide: Golterman and Shamir falsely claim that a waveguide model modified by adding\nmany charged bosonic spinors, in the limit of an infinite number of matter\nfields, becomes identical to the overlap if in the target theory every fermion\nappears in four copies. Their modified model would give wrong results even in\nthe vectorial four flavor massless Schwinger model, while a dynamical\nsimulation of this model with the overlap works correctly. In this note we\npinpoint the error in the derivation of Golterman and Shamir.",
        "positive": "Ghost propagator and the Coulomb form factor from the lattice: We calculate the Coulomb ghost propagator G(|p|) and the static Coulomb\npotential V_C(|r|) for SU(2) Yang-Mills theory on the lattice. In view of\npossible scaling violations related to deviations from the Hamiltonian limit we\nuse anisotropic lattices to improve the temporal resolution. We find that the\nghost propagator is infrared enhanced with an exponent kappa_gh ~ 0.5 while the\nCoulomb potential exhibits a string tension larger than the Wilson string\ntension, sigma_C ~ 2 sigma. This agrees with the Coulomb \"scaling\" scenario\nderived from the Gribov-Zwanziger confinement mechanism."
    },
    {
        "anchor": "P-vortices, nexuses and effects of Gribov copies in the center gauges: We perform the careful study of the Gribov copies problem in SU(2) lattice\ngauge theory for maximal direct and maximal indirect center projections. We\nfind that this problem is much more severe than it was thought before. The\nprojected string tension is not in agreement with the physical string tension.\nWe also show that the particle--like objects, nexuses, might be important for\nthe confinement dynamics.",
        "positive": "The pressure and a possible hidden Hagedorn transition at large-N: In the first part of this contribution we present a numerical study motivated\nby recent attempts to understand the nonperturbative aspects of QCD at\ntemperatures T~ a few times the deconfinement temperature Tc. We focus on the\npure gauge theory, and ask whether the deficit in pressure and entropy, with\nrespect to their free-gas values, is particular to SU(3). We find that the\ndeficit in SU(4),SU(8) for T>= 2Tc,1.6 Tc, respectively, is remarkably close to\nthat of SU(3). This suggests a similar deficit for SU(oo), which is fortunate\nsince this theory is simpler, and can serve to constrain the possible dynamics\nunderlying the deficits.\n  In the second part we seek for signs of a Hagedorn temperature T_H in pure\nlattice SU(N) gauge theories with N=8,10,12. Since one expects T_H>Tc, we\nmeasure masses of strings in the metastable confined phase above Tc, and\nextrapolatethem to zero to estimate T_H. For SU(12) we find that\nT_H/Tc=1.116(9), when we extrapolate with a critical exponentof the three\ndimensional XY model, which seems to be preferred over a mean field exponent by\nour data."
    },
    {
        "anchor": "The running of the coupling in SU(N) pure gauge theories: The running of the coupling is studied in SU(4) gauge theory using the\nSchr\\\"odinger functional technique. Up to energies of the order of the square\nroot of the string tension $\\sigma$, the running is found to agree with the\ntwo-loop perturbative formula. Relating the perturbative to the\nnon-perturbative regime of the running and converting to the $\\msbar$ scheme\nallows one to extract the ratio $\\Lambda_{\\msbar}/\\sqrt{\\sigma}$. The result is\nthen used in combination with similar calculations present in the literature\nfor SU(2) and SU(3) to extract $\\Lambda_{\\msbar}/\\sqrt{\\sigma}$ in the large\n$N$ limit. Our results for $N=3,4$ agree with a recent study of the same\nquantity performed using the Parisi mean field scheme as an intermediate\nscheme, while $\\Lambda_{\\msbar}/\\sqrt{\\sigma}$ in SU(2) turns out to differ by\n2.5%. Possible explanations of this discrepancy are discussed.",
        "positive": "Electromagnetic contributions to pseudoscalar masses: We report on the calculation by the MILC Collaboration of the electromagnetic\neffects on kaon and pion masses. These masses are computed in QCD with\ndynamical (asqtad staggered) quarks plus quenched photons at three lattice\nspacings varying from 0.12 to 0.06 fm. The masses are fit to staggered chiral\nperturbation theory with NLO electromagnetic terms, as well as analytic terms\nat higher order. We extrapolate the results to physical light-quark masses and\nto the continuum limit. At the current stage of the analysis, most, but not\nall, of the systematic errors have been estimated. The main goal is the\ncomparison of kaon electromagnetic splittings to those of the pion, i.e., an\nevaluation of the corrections to \"Dashen's theorem.\" This in turn will allow us\nto significantly reduce the systematic errors in our determination of m_u/m_d."
    },
    {
        "anchor": "DECONFINEMENT AND HOT HADRONS IN CRAYS AND QUADRICS: The equation of state of pure QCD, obtained from lattice QCD, is discussed\nfor temperatures ranging from $0.9\\tc$ to $4\\tc$, as well as results on\nscreening masses, the chiral condensate, and the pion decay constant close to\nthe deconfinement phase transition in the confined phase of QCD. The equation\nof state differs significantly from that of a free gas. There is little\nevidence of a temperature dependence in the chiral condensate or the meson\nproperties, but perhaps some for the nucleon screening mass. Above the phase\ntransition one sees non-perturbative effects, even though hadron correlators\nshow the existence of deconfined quarks.",
        "positive": "Mixed Meson Masses with Domain-Wall Valence and Staggered Sea Fermions: Mixed action lattice calculations allow for an additive lattice spacing\ndependent mass renormalization of mesons composed of one sea and one valence\nquark, regardless of the type of fermion discretization methods used in the\nvalence and sea sectors. The value of the mass renormalization depends upon the\nlattice actions used. This mixed meson mass shift is an important lattice\nartifact to determine for mixed action calculations; because it modifies the\npion mass, it plays a central role in the low energy dynamics of all hadronic\ncorrelation functions. We determine the leading order, $\\mathcal{O}(a^2)$, and\nnext to leading order, $\\mathcal{O}(a^2 m_\\pi^2)$, additive mass shift of\n\\textit{valence-sea} mesons for a mixed lattice action with domain-wall valence\nfermions and rooted staggered sea fermions, relevant to the majority of current\nlarge scale mixed action lattice efforts. We find that on the asqtad improved\ncoarse MILC lattices, this additive mass shift is well parameterized in lattice\nunits by $\\Delta(am)^2 = 0.034(2) -0.06(2) (a m_\\pi)^2$, which in physical\nunits, using $a=0.125$ fm, corresponds to $\\Delta(m)^2 = (291\\pm 8\n\\textrm{MeV})^2 -0.06(2) m_\\pi^2$. In terms of the mixed action effective field\ntheory parameters, the corresponding mass shift is given by $a^2\n\\Delta_\\mathrm{Mix} = (316 \\pm 4 \\textrm{MeV})^2$ at leading order plus\nnext-to-leading order corrections including the necessary chiral logarithms for\nthis mixed action calculation, determined in this work. Within the precision of\nour calculation, one can not distinguish between the full next-to-leading order\neffective field theory analysis of this additive mixed meson mass shift and the\nparameterization given above."
    },
    {
        "anchor": "Polarized and Unpolarized Nucleon Structure Functions from Lattice QCD: We report on a high statistics quenched lattice QCD calculation of the\ndeep-inelastic structure functions $F_1$, $F_2$, $g_1$ and $g_2$ of the proton\nand neutron. The theoretical basis for the calculation is the operator product\nexpansion. We consider the moments of the leading twist operators up to spin\nfour. Using Wilson fermions the calculation is done for three values of\n$\\kappa$, and we perform the extrapolation to the chiral limit. The\nrenormalization constants, which lead us from lattice to continuum operators,\nare calculated in perturbation theory to one loop order.",
        "positive": "Lattice QCD at the physical point: light quark masses: Ordinary matter is described by six fundamental parameters: three couplings\n(gravitational, electromagnetic and strong) and three masses: the electron's\n(m_e) and those of the up (m_u) and down (m_d) quarks. An additional mass\nenters through quantum fluctuations: the strange quark mass (m_s). The three\ncouplings and m_e are known with an accuracy of better than a few per mil.\nDespite their importance, $m_u$, $m_d$ (their average m_{ud}) and m_s are\nrelatively poorly known: e.g. the Particle Data Group quotes them with\nconservative errors close to 25%. Here we determine these quantities with a\nprecision below 2% by performing ab initio lattice quantum chromodynamics (QCD)\ncalculations, in which all systematics are controlled. We use pion and quark\nmasses down to (and even below) their physical values, lattice sizes of up to 6\nfm, and five lattice spacings to extrapolate to continuum spacetime. All\nnecessary renormalizations are performed nonperturbatively."
    },
    {
        "anchor": "Propagator zeros and lattice chiral gauge theories: Symmetric mass generation (SMG) has been advocated as a mechanism to render\nmirror fermions massive without symmetry breaking, ultimately aiming for the\nconstruction of lattice chiral gauge theories. It has been argued that in an\nSMG phase, the poles in the mirror fermion propagators are replaced by zeros.\nUsing an effective lagrangian approach, we investigate the role of propagator\nzeros when the gauge field is turned on, finding that they act as coupled ghost\nstates. In four dimensions, a propagator zero makes an opposite-sign\ncontribution to the one-loop beta function as compared to a normal fermion. In\ntwo dimensional abelian theories, a propagator zero makes a negative\ncontribution to the photon mass squared. In addition, propagator zeros generate\nthe same anomaly as propagator poles. Thus, gauge invariance will always be\nmaintained in an SMG phase, in fact, even if the target chiral gauge theory is\nanomalous, but unitarity of the gauge theory is lost.",
        "positive": "The three-loop beta function in SU(N) lattice gauge theories: We calculate the third coefficient of the lattice $\\beta$ function in pure\nYang-Mills theory. We make use of a computer code for solving perturbation\ntheory analytically on the lattice. We compute the divergent integrals by using\na method based on a Taylor expansion of the integrand in powers of the external\nmomenta in $4 - \\epsilon$ dimensions. Our results are in agreement with a\nprevious calculation by M. L\\\"uscher and P. Weisz where the authors used a\ndifferent technique. We also show how this new coefficient modifies the scaling\nfunction on the lattice in both the standard and energy schemes. In particular\nwe show that asymptotic scaling is extremely well achieved in the energy\nscheme."
    },
    {
        "anchor": "Chiral fermions on the lattice: We discuss topological obstructions to putting chiral fermions on an even\ndimensional lattice. The setting includes Ginsparg-Wilson fermions, but is more\ngeneral. We prove a theorem which relates the total chirality to the difference\nof generalised winding numbers of chiral projection operators. For an odd\nnumber of Weyl fermions this implies that particles and anti-particles live in\ntopologically different spaces.",
        "positive": "Proton momentum and angular momentum decompositions with overlap\n  fermions: We present a calculation of the proton momentum and angular momentum\ndecompositions using overlap fermions on a $2+1$-flavor RBC/UKQCD domain-wall\nlattice at 0.143 fm with a pion mass of 171 MeV which is close to the physical\none. A complete determination of the momentum and angular momentum fractions\ncarried by up, down, strange and glue inside the proton has been done with\nvalence pion masses varying from 171 to 391 MeV. We have utilized fast Fourier\ntransform on the stochastic-sandwich method for connected-insertion parts and\nthe cluster-decomposition error reduction technique for disconnected-insertion\nparts has been used to reduce statistical errors. The full nonperturbative\nrenormalization and mixing between the quark and glue operators are carried\nout. The final results are normalized with the momentum and angular momentum\nsum rules and reported at the physical valence pion mass at ${\\overline{\\rm\n{MS}}}\\, (\\mu = 2\\ {\\rm{GeV}})$. The renormalized momentum fractions for the\nquarks and glue are $\\langle x \\rangle^q = 0.491(20)(23)$ and $\\langle x\n\\rangle^g = 0.509(20)(23)$, respectively, and the renormalized total angular\nmomentum fractions for quarks and glue are $2 J^q = 0.539(22)(44)$ and $2 J^g =\n0.461(22)(44)$, respectively. The quark spin fraction is $\\Sigma =\n0.405(25)(37)$ from our previous work and the quark orbital angular momentum\nfraction is deduced from $2 L^q = 2 J^q - \\Sigma$ to be $0.134(22)(44)$."
    },
    {
        "anchor": "Hadronic light-by-light scattering amplitudes from lattice QCD versus\n  dispersive sum rules: The hadronic contribution to the eight forward amplitudes of light-by-light\nscattering ($\\gamma^*\\gamma^*\\to \\gamma^*\\gamma^*$) is computed in lattice QCD.\nVia dispersive sum rules, the amplitudes are compared to a model of the\n$\\gamma^*\\gamma^*\\to {\\rm hadrons}$ cross sections in which the fusion process\nis described by hadronic resonances. Our results thus provide an important test\nfor the model estimates of hadronic light-by-light scattering in the anomalous\nmagnetic moment of the muon, $a_\\mu^{\\rm HLbL}$. Using simple parametrizations\nof the resonance $M\\to \\gamma^*\\gamma^*$ transition form factors, we determine\nthe corresponding monopole and dipole masses by performing a global fit to all\neight amplitudes. Together with a previous dedicated calculation of the\n$\\pi^0\\to \\gamma^*\\gamma^*$ transition form factor, our calculation provides\nvaluable information for phenomenological estimates of $a_\\mu^{\\rm HLbL}$. The\npresented calculations are performed in two-flavor QCD with pion masses\nextending down to 190\\,MeV at two different lattice spacings. In addition to\nthe fully connected Wick contractions, on two lattice ensembles we also compute\nthe (2+2) disconnected class of diagrams, and find that their overall size is\ncompatible with a parameter-free, large-$N$ inspired prediction, where $N$ is\nthe number of colors. Motivated by this observation, we estimate in the same\nway the disconnected contribution to $a_\\mu^{\\rm HLbL}$.",
        "positive": "A Ginsparg-Wilson approach to lattice $\\mathcal{CP}$ symmetry: There is a long standing challenge in lattice QCD concerning the relationship\nbetween $\\mathcal{CP}$-symmetry and lattice chiral symmetry: na\\\"ively the\nchiral symmetry transformations are not invariant under $\\mathcal{CP}$. With\nresults similar to a recent work by Igarashi and Pawlowski, I show that this is\nbecause charge conjugation symmetry has been incorrectly realised on the\nlattice. The naive approach, to directly use the continuum charge conjugation\nrelations on the lattice, fails because the renormalisation group blockings\nrequired to construct a doubler free lattice theory from the continuum are not\ninvariant under charge conjugation. Correctly taking into account the\ntransformation of these blockings leads to a modified lattice $\\mathcal{CP}$\nsymmetry for the fermion fields, which, for gauge field configurations with\ntrivial topology, has a smooth limit to continuum $\\mathcal{CP}$ as the lattice\nspacing tends to zero. After constructing $\\mathcal{CP}$ transformations for\none particular group of lattice chiral symmetries, I construct a lattice chiral\ngauge theory which is $\\mathcal{CP}$ invariant and whose measure is invariant\nunder gauge transformations and $\\mathcal{CP}$."
    },
    {
        "anchor": "N_f=2+1 flavour equation of state: We conclude our investigation on the QCD equation of state (EoS) with 2+1\nstaggered flavors and one-link stout improvement. We extend our previous study\n[JHEP 0601:089 (2006)] by choosing even finer lattices. These new results [for\ndetails see arXiv:1007.2580] support our earlier findings. Lattices with\nN_t=6,8 and 10 are used, and the continuum limit is approached by checking the\nresults at N_t=12. A Symanzik improved gauge and a stout-link improved\nstaggered fermion action is taken; the light and strange quark masses are set\nto their physical values. Various observables are calculated in the temperature\n(T) interval of 100 to 1000~MeV. We compare our data to the equation of state\nobtained by the \"hotQCD\" collaboration.",
        "positive": "Lattice calculation of the pion transition form factor $\u03c0^0 \\to\n  \u03b3^* \u03b3^*$: We calculate the pion transition form factor ${\\cal\nF}_{\\pi^0\\gamma^*\\gamma^*}(q_1^2,q_2^2)$, which describe the interaction of an\non-shell pion with two off-shell photons, using lattice QCD simulations with\ntwo degenerate flavors of dynamical quarks. This form factor is the main\ningredient in the calculation of the pion-pole contribution to hadronic\nlight-by-light scattering in the muon $g-2$, $a_\\mu^{\\mathrm{HLbL}; \\pi^0}$. We\nfocus our study on the spacelike region with photon virtualities up to\n$1.5~\\mathrm{GeV}^2$, not yet measured experimentally. Several lattice spacings\nand pion masses are used to extrapolate the results to the physical point and a\ncomparison with different phenomenological models is performed. Finally, we use\nour extrapolated form factor to provide a lattice determinaiton of\n$a_\\mu^{\\mathrm{HLbL}; \\pi^0}$."
    },
    {
        "anchor": "The origin of space-time as seen from matrix model simulations: The AdS/CFT correspondence, or more generally the gauge/gravity duality, is a\nremarkable conjecture obtained from superstring theory with various D-brane\nbackgrounds. According to this conjecture, a higher-dimensional curved\nspace-time emerges from supersymmetric gauge theory in lower-dimensional flat\nspace-time. In the first part of this article, we review Monte Carlo studies of\nU(N) supersymmetric gauge theories, which confirmed the gauge/gravity duality\nfor various observables. In particular, Monte Carlo results for thermodynamic\nquantities enable us to understand the microscopic origin of the black hole\nentropy associated with the dual geometry. We also discuss results for Wilson\nloops and correlation functions, which agree nicely with the predictions from\nthe gravity side. In the second part, we review recent developments in a\nnonperturbative formulation of superstring theory, which may be regarded as a\ncounterpart of the lattice gauge theory in QCD. In particular, we discuss Monte\nCarlo results for the Lorentzian matrix model, which suggest that\n(3+1)-dimensional expanding universe emerges dynamically from type IIB\nsuperstring theory in (9+1) dimensions if one treats the theory\nnonperturbatively.",
        "positive": "Excited-state spectroscopy of singly, doubly and triply-charmed baryons\n  from lattice QCD: We present the ground and excited state spectra of singly, doubly and\ntriply-charmed baryons by using dynamical lattice QCD. A large set of baryonic\noperators that respect the symmetries of the lattice and are obtained after\nsubduction from their continuum analogues are utilized. These operators\ntransform as irreducible representations of SU(3)$_F$ symmetry for flavour,\nSU(4) symmetry for Dirac spins of quarks and O(3) symmetry for orbital angular\nmomenta. Using novel computational techniques correlation functions of these\noperators are generated and the variational method is exploited to extract\nexcited states. The lattice spectra that we obtain have baryonic states with\nwell-defined total spins up to 7/2 and the low lying states remarkably resemble\nthe expectations of quantum numbers from SU(6)$\\otimes$O(3) symmetry."
    },
    {
        "anchor": "Asymptotic Freedom and Euclidean Quantum Gravity: Pure SU(2) gauge theory is the simplest asymptotically free theory in four\ndimensions. To investigate Euclidean quantum gravity effects in a fundamental\nlength scenario, we simulate 4$d$ SU(2) lattice gauge theory on a dynamically\ncoupled Regge skeleton. The fluctuations of the skeleton are governed by the\nstandard Regge-Einstein action. From a small $2\\cdot 4^3$ lattice we report\nexploratory numerical results, limited to a region of strong gravity where the\nPlanck mass and hadronic masses take similar orders of magnitude. We find a\nrange of the Planck mass where stable bulk expectation values are obtained\nwhich vary smoothly with the gauge coupling, and a remnant of the QCD\ndeconfining phase transition is located. Note: The full ps file of this\npreprint is also available via anonymous ftp to ftp.scri.fsu.edu. To get the ps\nfile, ftp to this address and use for username \"anonymous\" and for password\nyour name. The file is in the directory pub/krishnan (to go to that directory\ntype: cd pub/krishnan) and is called gravity.ps (to get it type: get\ngravity.ps). If you have any problems send mail to krishnan@ds1.scri.fsu.edu.",
        "positive": "$O(\u03b1_{s}a)$ matching coefficients for axial vector current and\n  $\u0394B$$=$2 operator: We present a calculation of the perturbative matching coefficients including\nmixing with higher dimensional operators for the temporal component of the\nheavy-light axial current, $A_{4}$, and the $\\Delta B=2$ operator, $O_S$. For\n$A_{4}^{\\scriptsize static, NRQCD}$, calculations with various RG-improved\ngauge actions are peformed. Matching coefficients with NRQCD and heavy-clover\nactions are also compared."
    },
    {
        "anchor": "Examples of overlapping convergent expansions of scaling variables: We construct series expansions for the scaling variables (which transform\nmultiplicatively under a renormalization group (RG) transformation) in examples\nwhere the RG flows, going from an unstable (Wilson's) fixed point to a stable\n(high-temperature) fixed point, can be calculated numerically. The examples are\nDyson's hierarchical model and a simplified version of it. We provide numerical\nevidence that the scaling variables about the two fixed points have overlapping\ndomain of convergence. We show how quantities such as the magnetic\nsusceptibility can be expressed in terms of these variables. This procedure\nprovide accurate analytical expressions both in the critical and\nhigh-temperature region.",
        "positive": "Unquenching effects in the quark and gluon propagator: In this work we examine the Fat-Link Irrelevant Clover (FLIC) overlap quark\npropagator and the gluon propagator on both dynamical and quenched lattices.\nThe tadpole-improved Luscher-Weisz gauge action is used in both cases. The\ndynamical gauge fields use the FLIC fermion action for the sea quark\ncontribution. We observe that the presence of sea quarks causes a suppression\nof the mass function, quark renormalization function and gluon dressing\nfunction in the infrared. The ultraviolet physics is unaffected."
    },
    {
        "anchor": "From Spin Ladders to the 2-d O(3) Model at Non-Zero Density: The numerical simulation of various field theories at non-zero chemical\npotential suffers from severe complex action problems. In particular, QCD at\nnon-zero quark density can presently not be simulated for that reason. A\nsimilar complex action problem arises in the 2-d O(3) model -- a toy model for\nQCD. Here we construct the 2-d O(3) model at non-zero density via dimensional\nreduction of an antiferromagnetic quantum spin ladder in a magnetic field. The\ncomplex action problem of the 2-d O(3) model manifests itself as a sign problem\nof the ladder system. This sign problem is solved completely with a\nmeron-cluster algorithm.",
        "positive": "Study of Quark Confinement in Baryons with Lattice QCD: In SU(3) lattice QCD, we perform the detailed study for the ground-state\nthree-quark (3Q) potential $V_{\\rm 3Q}^{\\rm g.s.}$ and the 1st excited-state 3Q\npotential $V_{\\rm 3Q}^{\\rm e.s.}$, i.e., the energies of the ground state and\nthe 1st excited state of the gluon field in the presence of the static three\nquarks. From the accurate calculation for more than 300 different patterns of\n3Q systems, the static ground-state 3Q potential $V_{\\rm 3Q}^{\\rm g.s.}$ is\nfound to be well described by the Coulomb plus Y-type linear potential\n(Y-Ansatz) within 1%-level deviation. As a clear evidence for Y-Ansatz, Y-type\nflux-tube formation is actually observed on the lattice in maximally-Abelian\nprojected QCD. For about 100 patterns of 3Q systems, we calculate the 1st\nexcited-state 3Q potential $V_{\\rm 3Q}^{\\rm e.s.}$, and find a large\ngluonic-excitation energy $\\Delta E_{\\rm 3Q} \\equiv V_{\\rm 3Q}^{\\rm\ne.s.}-V_{\\rm 3Q}^{\\rm g.s.}$ of about 1 GeV, which gives a physical reason of\nthe success of the quark model even without gluonic excitations. We present\nalso the first study for the penta-quark potential $V_{\\rm 5Q}$ in lattice QCD,\nand find that $V_{\\rm 5Q}$ is well described by the sum of the OGE Coulomb plus\nmulti-Y type linear potential."
    },
    {
        "anchor": "Exploring QCD phase diagram at vanishing baryon density on the lattice: I report on the current status of QCD phase diagram at vanishing baryon\ndensity. I focus on the QCD phase diagram with three degenerate quark flavor\nusing Highly Improved Staggered Quarks on $N_{\\tau}=6$ lattices. No evidence of\na first order phase transition in the pion mass window of $80\\lesssim m_{\\pi}\n\\lesssim 230 $MeV is found. The pion mass at the critical point where the\nchiral first order phase transition ends is estimated to be $m^c_{\\pi} \\lesssim\n45$ MeV.",
        "positive": "On weak coupling expansion in models with unbroken symmetry: An investigation of the weak coupling region of 2D SU(N) spin models is\npresented. An expansion of the free energy and correlation functions at low\ntemperatures is performed in the link formulation with periodic boundary\nconditions (BC). The resulting asymptotics is shown to be nonuniform in the\nvolume for the free energy."
    },
    {
        "anchor": "Moments of structure functions for $N_f=2$ near the physical point: We report on our on-going study of the lower moments of iso-vector polarised\nand unpolarised structure functions, $g_A$ and $\\langle x\\rangle_{u-d}$,\nrespectively, and the iso-vector scalar and tensor charge, for $N_f=2$\nnon-perturbatively improved clover fermions. With pion masses which go down to\nabout 150 MeV, we investigate finite volume effects and excited state\ncontributions.",
        "positive": "Comparing meson-meson and diquark-antidiquark creation operators for a\n  $\\bar b \\bar b u d$ tetraquark: We compare two frequently discussed competing structures for a stable $\\bar b\n\\bar b u d$ tetraquark with quantum numbers $I(J^P) = 0(1^+)$ by considering a\nmeson-meson as well as a diquark-antidiquark creation operator. We treat the\nheavy antiquarks as static with fixed positions and find diquark-antidiquark\ndominance for $\\bar b \\bar b$ separations $r < 0.2 \\, \\text{fm}$, while for $r\n> 0.5 \\, \\text{fm}$ the system essentially corresponds to a pair of $B$ mesons.\nFor the meson-meson to diquark-antidiquark ratio of the tetraquark we obtain\naround $58\\%/42\\%$."
    },
    {
        "anchor": "Lattice operators for scattering of particles with spin: We construct operators for simulating the scattering of two hadrons with spin\non the lattice. Three methods are shown to give the consistent operators for\nPN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and\nnucleon. Explicit expressions for operators are given for all irreducible\nrepresentations at lowest two relative momenta. Each hadron has a good helicity\nin the first method. The hadrons are in a certain partial wave L with total\nspin S in the second method. These enable the physics interpretations of the\noperators obtained from the general projection method. The correct\ntransformation properties of the operators in all three methods are proven. The\ntotal momentum of two hadrons is restricted to zero since parity is a good\nquantum number in this case.",
        "positive": "Calculating the QED correction to the hadronic vacuum polarisation on\n  the lattice: Isospin-breaking corrections to the hadron vacuum polarization component of\nthe anomalous magnetic moment of the muon are needed to ensure the theoretical\nprecision of $g_\\mu -2$ is below the experimental precision. We describe the\nstatus of our work calculating, using lattice QCD, the QED correction to the\nlight and strange connected hadronic vacuum polarization in a Dashen scheme. We\nreport results using physical $N_f=2+1+1$ HISQ ensembles at three lattice\nspacings and three heavier-than-light valence quark masses."
    },
    {
        "anchor": "Mitigating the sign problem for non-relativistic fermions on the lattice: We study the fermion sign problem in a theory of non-relativistic fermions\nwith a spin-independent repulsive interaction. We work in polar co-ordinates in\nmomentum space, which makes it straightforward to keep only the low-energy\ndegrees of freedom close to the Fermi surface. This is sufficient for the\npurpose of calculating many physically important low-energy observables. We\nfind indications that the sign problem in this effective theory will be weaker\nthan in the full theory, so low-energy properties of the theory could be\ncalculated by modifying the action to make it positive semi-definite and\nincluding reweighting factors in the observables. We discuss suitable\nmodifications of the action, and describe a possible lattice realization of the\npolar momentum space formulation of the theory.",
        "positive": "The strangeness magnetic moment of the nucleon from FLIC fermions: By imposing the constraints of charge symmetry we show that the strangeness\nmagnetic moment of the nucleon can be expressed in terms of empirical magnetic\nmoments and ratios of valence quark magnetic moments. The latter are determined\nusing modern chiral extrapolation techniques and recent low mass lattice QCD\nsimulations of the individual quark contributions to the magnetic moments of\nthe nucleon octet. The result is a precise determination of G_M^s, namely\n-0.043 +/- 0.026 mu_N, which is consistent with the latest experimental\nmeasurements."
    },
    {
        "anchor": "Meson-Baryon Scattering Parameters from Lattice QCD with an Isospin\n  Chemical Potential: The extraction of meson-baryon scattering parameters from lattice QCD is\ncomplicated by the necessity, in some channels, of including annihilation\ndiagrams. We consider a strategy to avoid the need for these extremely costly\nand noisy contributions. The strategy is based on simulations with an isospin\nchemical potential which, contrary to a baryon chemical potential, has no sign\nproblem. When the isospin chemical potential is larger than a critical value, a\ncharged pion condensate forms. Baryons propagating in the pion condensate will\nhave their masses modified by pion-baryon scattering parameters. Consequently\nthese parameters can be extracted from lattice QCD simulations in an isospin\nchemical potential, and we detail precisely which low-energy constants using\nbaryon chiral perturbation theory.",
        "positive": "An solvable three-body model in finite volume: In this work, based on consideration of periodicity and asymptotic forms of\nwave function, we propose a novel approach to the solution of finite volume\nthree-body problem by mapping a three-body problem into a higher dimensional\ntwo-body problem. The idea is demonstrated by an example of two light spinless\nparticles and one heavy particle scattering in one spatial dimension. This 1D\nthree-body problem resembles a two-body problem in two spatial dimensions\nmathematically, and quantization condition of 1D three-body problem is thus\nderived accordingly."
    },
    {
        "anchor": "Stochastic field evolution of disoriented chiral condensates: I present a summary of recent work \\cite{BRS} where we describe the\ntime-evolution of a region of disoriented chiral condensate via Langevin field\nequations for the linear $\\sigma$ model. We analyze the model in equilibrium,\npaying attention to subtracting ultraviolet divergent classical terms and\nreplacing them by their finite quantum counterparts. We use results from\nlattice gauge theory and chiral perturbation theory to fix nonuniversal\nconstants. The result is a ultraviolet cutoff independent theory that\nreproduces quantitatively the expected equilibrium behavior of pion and\n$\\sigma$ quantum fields. We also estimate the viscosity $\\eta(T)$, which\ncontrols the dynamical timescale in the Langevin equation, so that the near\nequilibrium dynamical response agrees with theoretical expectations.",
        "positive": "Chiral fermion operators on the lattice: We only require generalized chiral symmetry and $\\gamma_5$-hermiticity, which\nleads to a large class of Dirac operators describing massless fermions on the\nlattice, and use this framework to give an overview of developments in this\nfield. Spectral representations turn out to be a powerful tool for obtaining\ndetailed properties of the operators and a general construction of them. A\nbasic unitary operator is seen to play a central r\\^ole in this context. We\ndiscuss a number of special cases of the operators and elaborate on various\naspects of index relations. We also show that our weaker conditions lead still\nproperly to Weyl fermions and to chiral gauge theories."
    },
    {
        "anchor": "Towards lattice simulation of the gauge theory duals to black holes and\n  hot strings: A generalization of the AdS/CFT conjecture postulates a duality between IIA\nstring theory and 16 supercharge Yang-Mills quantum mechanics in the large N 't\nHooft limit. At low temperatures string theory describes black holes, whose\nthermodynamics may hence be studied using the dual quantum mechanics. This\nquantum mechanics is strongly coupled which motivates the use of lattice\ntechniques. We argue that, contrary to expectation, the theory when discretized\nnaively will nevertheless recover continuum supersymmetry as the lattice\nspacing is sent to zero. We test these ideas by studying the 4 supercharge\nversion of this Yang-Mills quantum mechanics in the 't Hooft limit. We use both\na naive lattice action and a manifestly supersymmetric action. Using Monte\nCarlo methods we simulate the Euclidean theories, and study the lattice\ncontinuum limit, for both thermal and non-thermal periodic boundary conditions,\nconfirming continuum supersymmetry is recovered for the naive action when\nappropriate. We obtain results for the thermal system with N up to 12. These\nfavor the existence of a single deconfined phase for all non-zero temperatures.\nThese results are an encouraging indication that the 16 supercharge theory is\nwithin reach using similar methods and resources.",
        "positive": "Light hadron spectroscopy with two flavors of $O(a)$-improved dynamical\n  quarks: We present a high statistics study of the light hadron spectrum and quark\nmasses in QCD with two flavors of dynamical quarks. Numerical simulations are\ncarried out using the plaquette gauge action and the O(a)-improved Wilson quark\naction at \\beta=5.2, where the lattice spacing is found to be a=0.0887(11)fm\nfrom \\rho meson mass, on a 20^3\\times 48 lattice. At each of five sea quark\nmasses corresponding to m_{PS}/m_{V} \\simeq 0.8-0.6, we generate 12000\ntrajectories using the symmetrically preconditioned Hybrid Monte Carlo\nalgorithm. Finite spatial volume effects are investigated employing 12^3 \\times\n48, 16^3 \\times 48 lattices. We also perform a set of simulations in quenched\nQCD with the same lattice actions at a similar lattice spacing to those for the\nfull QCD runs. In the meson sector we find clear evidence of sea quark effects.\nThe J parameter increases for lighter sea quark masses, and the full QCD meson\nmasses are systematically closer to experiment than in quenched QCD. Careful\nfinite-size studies are made to ascertain that these are not due to finite-size\neffects. Evidence of sea quark effects is less clear in the baryon sector due\nto larger finite-size effects. We also calculate light quark masses and find\nm_{ud}^{MS}(2GeV) =3.223(+0.046/-0.069)MeV and\nm_s^{MS}(2GeV)=84.5(+12.0/-1.7)MeV which are about 20% smaller than in quenched\nQCD."
    },
    {
        "anchor": "Decay constants of the pion and its excitations on the lattice: We present a calculation using lattice QCD of the ratios of decay constants\nof the excited states of the pion, to that of the pion ground state, at three\nvalues of the pion mass between 400 and 700 MeV, using an anisotropic clover\nfermion action with three flavors of quarks. We find that the decay constant of\nthe first excitation, and more notably of the second, is suppressed with\nrespect to that of the ground-state pion, but that the suppression shows little\ndependence on the quark mass. The strong suppression of the decay constant of\nthe second excited state is consistent with its interpretation as a\npredominantly hybrid state.",
        "positive": "Optimized Two-Baryon Operators in Lattice QCD: A set of optimized interpolating operators which are dominantly coupled to\neach eigenstate of two baryons on the lattice is constructed by the HAL QCD\nmethod. To test its validity, we consider heavy dibaryons\n$\\Omega_{3Q}\\Omega_{3Q}$ ($Q=s,c$) calculated by (2+1)-flavor lattice QCD\nsimulations with nearly physical pion mass. The optimized two-baryon operators\nare shown to provide effective energies of the ground and excited states\nseparately stable as a function of the Euclidean time. Also they agree to the\neigenenergies in a finite lattice box obtained from the leading-order HAL QCD\npotential $V({\\boldsymbol{r}})$ within statistical errors. The overlapping\nfactors between the optimized sink operators and the state created by the\nwall-type source operator indicate that $V( \\boldsymbol{r})$ can be reliably\nextracted, no matter whether the spacetime correlation of two baryons is\ndominated by the ground state or the excited state. It is suggested that the\noptimized set of operators is useful for variational studies of hadron-hadron\ninteractions."
    },
    {
        "anchor": "The low-lying Scalar Mesons and Related Topics: After presenting the motivations to explore the low-lying scalar mesons such\nas the $\\sigma$, $a_0$ and $\\kappa$ in the unquenched as well as quenched\nlattice QCD, we review the works done by our collaboration (SCALAR\nCollaboration) with a what-to-do-next list. We briefly mention the imporatance\nto explore the $N_c$ dependence of and possible effects of the $U_A(1)$ anomaly\nto the properties the low-lying scalar mesons.",
        "positive": "Lattice Chirality and its uses at large N: A brief overview of the authors' work on lattice chirality and its\napplication to the numerical study of planar QCD is presented."
    },
    {
        "anchor": "Simulations of gaussian systems in Minkowski time: Many research programs aiming to deal with the sign problem were proposed\nsince the advent of lattice field theory. Several of these try to achieve this\nby exploiting properties of analytic functions. This is also the case for our\nstudy. There auxiliary complex variables are introduced and desired weight is\nobtained after integrating them out. In this note we clarify conceptual\ndifficulties with this procedure encountered in previous works. In the process\nwe observe an exciting connection with thimbles and discover an interesting\nhidden symmetry present in the problem. Problem of negative eigenvalues of the\naction will be revisited and considered from a different perspective. As a\nbyproduct we perform simulations of simple quantum systems directly in\nMinkowski time.",
        "positive": "Prony methods for extracting excited states: We propose an algebraic method for extracting excited states from lattice\ngauge theory correlation functions. Instead of fitting to a sum of decaying\nexponentials, we adopt a variant of Prony's method to obtain $M$ energies\n(exponential decay rates) by finding the roots of an $M^{\\rm th}$ order\npolynomial, and then solving for the amplitudes linearly. The resulting states\ntend to have overlapping error ellipses, making identification of states\nambiguous. This is especially problematic at large Euclidean times where the\nsignal to noise may be low, as well as when many states are extracted. We\npropose a variation of K-means clustering to identify each extracted state."
    },
    {
        "anchor": "A qubit regularization of asymptotic freedom without fine-tuning: Other than the commonly used Wilson's regularization of quantum field\ntheories (QFTs), there is a growing interest in regularizations that explore\nlattice models with a strictly finite local Hilbert space, in anticipation of\nthe upcoming era of quantum simulations of QFTs. A notable example is Euclidean\nqubit regularization, which provides a natural way to recover continuum QFTs\nthat emerge via infrared fixed points of lattice theories. Can such\nregularizations also capture the physics of ultraviolet fixed points? We\npresent a novel regularization of the asymptotically free massive continuum QFT\nthat emerges at the Berezenski-Kosterlitz-Thouless (BKT) transition through a\nhard core loop-gas model, discussing the advantages this model provides\ncompared to traditional regularizations. In particular, we demonstrate that\nwithout the need for fine-tuning, it can reproduce the universal step-scaling\nfunction of the classical lattice XY model in the massive phase as we approach\nthe phase transition.",
        "positive": "2+1 flavour thermal studies on an anisotropic lattice: The FASTSUM collaboration has initiated a detailed study of thermal QCD using\n2+1 flavours of improved Wilson quarks on anisotropic lattices. Spatial volumes\nof (3fm)^3 and (4fm)^3 are used at fixed cut-off with temperatures ranging from\n40 to 350 MeV (corresponding to temporal lattice extents of 128 to 16 lattice\nunits). Results presented here include the deconfinement temperature and a\nstudy of the restoration of chiral symmetry, together with a brief summary of\nour collaboration's other results from these ensembles."
    },
    {
        "anchor": "Use and misuse of ChPT in the heavy-light systems: We discuss the range of validity of ChPT when applied to the systems of\nheavy-light mesons. Having in mind the recent experimental evidence according\nto which the heavy-light scalar and axial states are closer to the ground\nstates than anticipated, we revisited the prediction for the chiral behavior of\nthe B-Bbar mixing amplitude and examined the impact of nearness of the positive\nparity states. We conclude that the standard ChPT expressions with Nf=3 light\nflavours are not useful in guiding the extrapolation of hadronic quantities\ncomputed on the lattice. Instead those derived in HMChPT with Nf=2, i.e.,\nincluding only the pion loops, are still adequate as long as they are applied\nto the pions lighter than 350 MeV, or the quarks lighter than a third of the\nphysical strange quark mass.",
        "positive": "Universality of 2d Yukawa and Gross-Neveu models: Evidence for the same universal behavior of 2d Yukawa and Gross-Neveu models\nin a certain range of couplings, particularly for $\\kappa<0$, is presented."
    },
    {
        "anchor": "Chiral transition and deconfinement transition in QCD with the highly\n  improved staggered quark (HISQ) action: We report preliminary results on the chiral and deconfinement aspects of the\nQCD transition at finite temperature using the Highly Improved Staggered Quark\n(HISQ) action on lattices with temporal extent of N_{\\tau}=6 and 8. The chiral\naspects of the transition are studied in terms of quark condensates and the\ndisconnected chiral susceptibility. We study the deconfinement transition in\nterms of the strange quark number susceptibility and the renormalized Polyakov\nloop. We made continuum estimates for some quantities and find reasonably good\nagreement between our results and the recent continuum extrapolated results\nobtained with the stout staggered quark action.",
        "positive": "Polyakov loop fluctuations in SU(3) lattice gauge theory and an\n  effective gluon potential: We calculate the Polyakov loop susceptibilities in the SU(3) lattice gauge\ntheory using the Symanzik improved gauge action on different-sized lattices.\nThe longitudinal and transverse fluctu- ations of the Polyakov loop, as well\nas, that of its absolute value are considered. We analyze their properties in\nrelation to the confinement-deconfinement phase transition. We also present\nresults based on simulations of (2+1)-flavor QCD on 32^3 x 8 lattice using\nHighly Improved Staggered Quark (HISQ) action by the HotQCD collaboration. The\ninfluences of fermions on the Polyakov loop fluctuations are discussed. We\nshow, that ratios of different susceptibilities of the Polyakov loop are\nsensitive probes for critical behavior. We formulate an effective model for the\nPolyakov loop potential and constrain its parameters from existing quenched\nlattice data including fluctuations. We emphasize the role of fluctuations to\nfully explore the thermodynamics of pure gauge theory within an effective\napproach."
    },
    {
        "anchor": "Does the XY Model have an integrable continuum limit?: The quantum field theory describing the massive O(2) nonlinear sigma-model is\ninvestigated through two non-perturbative constructions: The form factor\nbootstrap based on integrability and the lattice formulation as the XY model.\nThe S-matrix, the spin and current two-point functions, as well as the 4-point\ncoupling are computed and critically compared in both constructions. On the\nbootstrap side a new parafermionic super selection sector is found; in the\nlattice theory a recent prediction for the (logarithmic) decay of lattice\nartifacts is probed.",
        "positive": "Lattice QCD study of the rare kaon decay $K^+\\to\u03c0^+\u03bd\\bar\u03bd$ at a\n  near-physical pion mass: The rare kaon decay $K^+\\to\\pi^+\\nu\\bar{\\nu}$ is an ideal process in which to\nsearch for signs of new physics and is the primary goal of the NA62 experiment\nat CERN. In this paper we report on a lattice QCD calculation of the\nlong-distance contribution to the $K^+\\to\\pi^+\\nu\\bar{\\nu}$ decay amplitude at\nthe near-physical pion mass $m_\\pi=170$ MeV. The calculations are however,\nperformed on a coarse lattice and hence with a lighter charm quark mass\n($m_c^{\\bar{\\mathrm{MS}}}(\\mbox{3 GeV})=750$ MeV) than the physical one. The\nmain aims of this study are two-fold. Firstly we study the momentum dependence\nof the amplitude and conclude that it is very mild so that a computation at\nphysical masses even at a single kinematic point would provide a good estimate\nof the long-distance contribution to the decay rate. Secondly we compute the\ncontribution to the branching ratio from the two-pion intermediate state whose\nenergy is below the kaon mass and find that it is less than 1% after its\nexponentially growing unphysical contribution has been removed and that the\ncorresponding non-exponential finite-volume effects are negligibly small."
    },
    {
        "anchor": "Low-Temperature Expansion of the Free Energy in ASOS Model: We calculate the low-temperature series of the free energy in absolute-value\nsolid-on-solid (ASOS) model to order $u^{23}$ using finite-lattice method. The\nproperty of the obtained series and the behavior of their Pad\\'e approximants\nconfirms us that the roughening transition in ASOS model is of\nKosterlitz-Thouless type.",
        "positive": "Spectroscopy of light tetraquark states: We address the question whether the lightest scalar mesons sigma and kappa\nare tetraquarks, as is strongly supported by many phenomenological studies. We\npresent a search for possible light tetraquark states with J^PC=0^++ and I=0,\n1/2, 3/2, 2 on the lattice. The spectrum is determined using the generalized\neigenvalue method with a number of tetraquark interpolators at the source and\nthe sink. In all the channels, we unavoidably find lowest scattering states\npi(k)pi(-k) or K(k)pi(-k) with back-to-back momentum k=0,2*pi/L,.. . However,\nwe find an additional light state in the I=0 and I=1/2 channels, which may be\nrelated to the observed resonances sigma and kappa with a strong tetraquark\ncomponent. In the exotic repulsive channels I=2 and I=3/2, where no resonance\nis observed, we find no light state in addition to the scattering states."
    },
    {
        "anchor": "Casimir Scaling and String Breaking in G(2) Gluodynamics: We study the potential energy between static charges in G(2) gluodynamics in\nthree and four dimensions. Our work is based on an efficient local hybrid\nMonte-Carlo algorithm and a multi-level L\\\"uscher-Weisz algorithm with\nexponential error reduction to accurately measure expectation values of Wilson-\nand Polyakov loops. Both in three and four dimensions we show that at\nintermediate scales the string tensions for charges in various\nG(2)-representations scale with the second order Casimir. In three dimensions\nCasimir scaling is confirmed within one percent for charges in representations\nof dimensions 7, 14, 27, 64, 77, 77', 182 and 189 and in 4 dimensions within 5\npercent for charges in representions of dimensions 7, 14, 27 and 64. In three\ndimensions we detect string breaking for charges in the two fundamental\nrepresentations. The scale for string breaking agrees very well with the mass\nof the created pair of glue-lumps.",
        "positive": "Sum rules and 2-quark flux-tube structure: Sum rules -- relating the static quark potential V(R) to the spatial\ndistribution of the action and energy in the colour fields of flux-tubes -- are\napplied in three ways: 1) To extract generalised beta-functions: 2) As a\nconsistency check for the use of excited gluon flux-tubes and as an estimate of\nthe quark self-energies: 3) To extract approximate sum rules using a simplified\nform of V(R). Also the flux-tube profiles are compared with hadronic string and\nflux-tube models."
    },
    {
        "anchor": "Practical all-to-all propagators for lattice QCD: A new method for computing all elements of the lattice quark propagator is\nproposed. The method combines the spectral decomposition of the propagator,\ncomputing the lowest eigenmodes exactly, with noisy estimators which are\n'diluted', i.e. taken to have support only on a subset of time, space, spin or\ncolour. We find that the errors are dramatically reduced compared to\ntraditional noisy estimator techniques.",
        "positive": "Spectral-weight sum rules for the hadronic vacuum polarization: We develop a number of sum rules comparing spectral integrals involving\njudiciously chosen weights to integrals over the corresponding Euclidean\ntwo-point function. The applications we have in mind are to the hadronic vacuum\npolarization that determines the most important hadronic correction $a_\\mu^{\\rm\nHVP}$ to the muon anomalous magnetic moment. First, we point out how spectral\nweights may be chosen that emphasize narrow regions in $\\sqrt{s}$, providing a\ntool to investigate emerging discrepancies between data-driven and lattice\ndeterminations of $a_\\mu^{\\rm HVP}$. Alternatively, for a narrow region around\nthe $\\rho$ mass, they may allow for a comparison of the dispersive\ndetermination of $a_\\mu^{\\rm HVP}$ with lattice deteruminations zooming in on\nthe region of the well-known BaBar-KLOE discrepancy. Second, we show how such\nsum rules can in principle be used for carrying out precision comparisons of\nhadronic-$\\tau$-decay-based data and $e^+e^-\\to\\mbox{hadrons}(\\gamma)$-based\ndata, where lattice computations can provide the necessary isospin-breaking\ncorrections."
    },
    {
        "anchor": "Nonlocal lattice fermion models on the 2d torus: Abelian fermion models described by the SLAC action are considered on a\nfinite 2d lattice. It is shown that modification of these models by introducing\nadditional Pauli - Villars regularization supresses nonlocal effects and\nprovides agreement with the continuum results in vectorial U(1) models. In the\ncase of chiral fermions the phase of the determinant differs from the continuum\none.",
        "positive": "Status and challenges of simulations with dynamical fermions: An overview over the current state of algorithms for dynamical fermion\nsimulations is given. In particular some insight into the functioning of the\ndeterminant spitting techniques is discussed. The critical slowing down of the\nsimulations towards the continuum limit and the role of the boundary conditions\nis also reviewed."
    },
    {
        "anchor": "Planar diagrams for lattice gauge theory on finite tori: An $N=\\infty$ equivalence among quenched $U(N)$ models on finite lattice tori\nof $V$ sites is proven to all orders in planar perturbation theory by putting\ncirculant lattice momenta together with group indices on 't Hooft's double\nlines. Known estimates for the number of order $N^2$ diagrams, $N\\gg V$, and\nthe simultaneous presence of UV and IR cutoffs, suggest a positive radius of\nconvergence for the planar perturbative expansion before the limit $N=\\infty$\nis taken.",
        "positive": "Effects of Chemical Potential on Hadron Masses in the Phase Transition\n  Region: We study the response of hadron masses with respect to chemical potential at\n$\\mu=0$. Our preliminary results of the pion channel show that $\\partial\nm/\\partial \\mu$ in the confinement phase is significantly larger than that in\nthe deconfinement phase, which is consistent with the chiral restoration."
    },
    {
        "anchor": "Functional integration on Regge geometries: We adopt the standard definition of diffeomorphism for Regge gravity in D=2\nand give an exact expression of the Liouville action in the discretized case.\nWe also give the exact form of the integration measure for the conformal\nfactor. In D>2 we extend the approach to any family of geometries described by\na finite number of parameters. The ensuing measure is a geometric invariant and\nit is also invariant in form under an arbitrary change of parameters.",
        "positive": "Bose Condensation and $Z_N$ Symmetry Breaking in the Mixed Model of\n  Induced QCD: The mixed model of the large $ N $ induced QCD, with $ N_f \\ll N $ flavors of\nheavy fermions in fundamental representation, is solved in the local limit. The\n$ Z_N$ symmetry is broken spontaneously in the large $ N $ limit, evading the\nElitzur \"no-go\" theorem. As a result of this symmetry breaking, there is the\nBose condensate of the eigenvalues of the scalar field, proportional to $\n\\frac{N_f}{N} $. This condensate leads to the mass unit, which goes to zero as\nfractional power of $ \\frac{N_f}{N} $, thus defining the new kind of the local\nlimit of this lattice theory. There is a strong coupling region below this mass\nscale, which revives the hopes of induction of realistic QCD."
    },
    {
        "anchor": "B Semileptonic Decays at High Recoil Momentum: We explore the possibility of studying $B\\to\\pi l\\nu$ semileptonic decays at\nlarge recoil momentum. Our methods include the use of a random-wall source for\nthe pion to reduce statistical errors, and different smearing functions are\nused for the B meson to improve the overlap with the ground state. We observe,\nin general, a factor of 3-4 improvement in the signal-to-noise ratio in\ncorrelation functions if random-wall propagators are used.",
        "positive": "Perturbative Matching of the NRQCD Heavy-Light Axial Current: A one-loop matching calculation between Lattice NRQCD and full QCD for the\nheavy-light axial current is described and the effects on f_B are discussed."
    },
    {
        "anchor": "The Phases and Triviality of Scalar Quantum Electrodynamics: The phase diagram and critical behavior of scalar quantum electrodynamics are\ninvestigated using lattice gauge theory techniques. The lattice action fixes\nthe length of the scalar (``Higgs'') field and treats the gauge field as\nnon-compact. The phase diagram is two dimensional. No fine tuning or\nextrapolations are needed to study the theory's critical behovior. Two lines of\nsecond order phase transitions are discovered and the scaling laws for each are\nstudied by finite size scaling methods on lattices ranging from $6^4$ through\n$24^4$. One line corresponds to monopole percolation and the other to a\ntransition between a ``Higgs'' and a ``Coulomb'' phase, labelled by divergent\nspecific heats. The lines of transitions cross in the interior of the phase\ndiagram and appear to be unrelated. The monopole percolation transition has\ncritical indices which are compatible with ordinary four dimensional\npercolation uneffected by interactions. Finite size scaling and histogram\nmethods reveal that the specific heats on the ``Higgs-Coulomb'' transition line\nare well-fit by the hypothesis that scalar quantum electrodynamics is\nlogarithmically trivial. The logarithms are measured in both finite size\nscaling of the specific heat peaks as a function of volume as well as in the\ncoupling constant dependence of the specific heats measured on fixed but large\nlattices. The theory is seen to be qualitatively similar to $\\lambda\\phi^{4}$.\nThe standard CRAY random number generator RANF proved to be inadequate",
        "positive": "$\u03b8$ dependence in trace deformed $SU(3)$ Yang-Mills theory: a\n  lattice study: In this paper we investigate, by means of numerical lattice simulations, the\ntopological properties of the trace deformed $SU(3)$ Yang-Mills theory defined\non $S_1\\times\\mathbb{R}^3$. More precisely, we evaluate the topological\nsusceptibility and the $b_2$ coefficient (related to the fourth cumulant of the\ntopological charge distribution) of this theory for different values of the\nlattice spacing and of the compactification radius. In all the cases we find\nresults in good agreement with the corresponding ones of the standard $SU(3)$\nYang-Mills theory on $\\mathbb{R}^4$."
    },
    {
        "anchor": "On the three-particle analog of the Lellouch-L\u00fcscher formula: Using non-relativistic effective field theory, we derive a three-particle\nanalog of the Lellouch-L\\\"uscher formula at the leading order. This formula\nrelates the three-particle decay amplitudes in a finite volume with their\ninfinite-volume counterparts and, hence, can be used to study the\nthree-particle decays on the lattice. The generalization of the approach to\nhigher orders is briefly discussed.",
        "positive": "Quasi-PDFs with twisted mass fermions: We discuss the recent progress in extracting partonic functions from the\nquasi-distribution approach, using twisted mass fermions. This concerns, among\nothers, the investigation of several sources of systematic effects. Their\ncareful analysis is a prerequisite to obtain precise determinations of PDFs\nfrom the lattice with realistic estimates of all uncertainties. In these\nproceedings, we shortly discuss systematic effects in the matching procedure.\nMoreover, we present preliminary results from our new simulations at the\nphysical point. They involve, additionally, the dynamical strange and charm\nquarks, as well as a larger volume and a smaller lattice spacing than in our\nprevious computations. In addition, we show first results from computations of\ngeneralized parton distributions (GPDs) in the quasi-distribution framework."
    },
    {
        "anchor": "Beyond the Standard Model with Precision Nucleon Matrix Elements on the\n  Lattice: Precision measurements of nucleons provide constraints on the Standard Model\nand can discern the signatures predicted for particles beyond the Standard\nModel (BSM). Knowing the Standard Model inputs to nucleon matrix elements will\nbe necessary to constrain the couplings of dark matter candidates such as the\nneutralino, to relate the neutron electric dipole moment to the CP-violating\ntheta parameter, or to search for new TeV-scale particles though non-$V-A$\ninteractions in neutron beta decay. However, these matrix elements derive from\nthe properties of quantum chromodynamics (QCD) at low energies, where\nperturbative treatments fail. Using lattice gauge theory, we can\nnonperturbatively calculate the QCD path integral on a supercomputer. In this\nproceeding, I will discuss a few representative areas in which lattice QCD\n(LQCD) can contribute to the search for BSM physics, emphasizing suppressed\noperators in neutron decay, and outline prospects for future development.",
        "positive": "Lattice Analysis of Two-Point Hadronic Correlators in the QCD Vacuum: Results from the first lattice QCD analysis of vacuum correlators of local\nhadronic currents using dispersion relations are presented. We have explored\nthe vector, pseudoscalar, axial, and scalar meson channels, and the proton-like\nand delta-like baryon channels. The lattice results are shown to agree\nqualitatively with experimental results in channels where experimental data\nexist, and shed insight into interacting instanton approximations and sum rule\ncalculations in the other channels.\n  3 figures included (as PostScript files): pi.ps, nd.ps, va.ps : Search for\n%%% to retrieve the files. Latex file, needs espcrc2.sty (Search for %%%)."
    },
    {
        "anchor": "Pion Distribution Amplitudes in the Continuum Limit: We present a lattice-QCD calculation of the pion distribution amplitudes\nusing large-momentum effective theory (LaMET). Our calculation is carried out\nusing five ensembles with 2+1+1 flavors of highly improved staggered quarks\n(HISQ), generated by MILC collaboration, at 310 MeV and 220 MeV pion mass with\n0.06, 0.09, 0.12 and 0.15 fm lattice spacings. We use clover fermion action for\nthe valence quarks and tune the quark mass to match the lightest light and\nstrange masses in the sea. The resulting lattice matrix elements are\nnonperturbatively renormalized in regularization-independent\nmomentum-subtraction (RI/MOM) scheme and extrapolated to the continuum. We\ncompare different approaches to extract the x-dependence of the pion\ndistribution amplitudes.",
        "positive": "Twisted mass QCD thermodynamics: first results on apeNEXT: The motivations for simulating QCD thermodynamics with Wilson fermions and a\ntwisted mass term are introduced. The twisted mass approach provides a natural\ninfrared cutoff and O(a) improvement at maximal twist, and can be extended to\nfinite temperature. Our strategy for exploring the QCD phase diagram at finite\ntemperature in this setup, while taking advantage of the results at T=0, is\nexplained. The first results for the order parameters and susceptibilities on a\n16^3 x 8 lattice are presented. All dynamical simulations are carried out on\nthe apeNEXT facility in Rome."
    },
    {
        "anchor": "Bound on the string tension by the excitation probability for a vortex: A lower bound on the string tension for large beta in SU(2) LGT is derived.\nThe derivation is from first principles and bounds the string tension from\nbelow by the expectation for the excitation of a single `tagged' thick vortex\nwinding around the lattice. Thus confinement follows if this expectation\nremains nonvanishing at large beta. Numerical simulations are presented to show\nthat this is indeed the case.",
        "positive": "Deep Learning of Fermion Sign Fluctuations: We describe a procedure for alleviating the fermion sign problem in which\nphase fluctuations are explicitly subtracted from the Boltzmann factor. Several\nans\\\"atze for fluctuations are designed and compared. In the absence of a\nsufficiently high-quality ansatz, a neural network can be trained to\nparameterize the fluctuations. Demonstrating on the staggered Thirring model in\n$1+1$ dimensions, we examine the performance of this method as deeper neural\nnetworks are used, and in conjunction with the well-studied contour deformation\nmethods."
    },
    {
        "anchor": "Dual simulation of the 2d U(1) gauge Higgs model at topological angle\n  $\u03b8= \u03c0\\,$: Critical endpoint behavior: We simulate the 2d U(1) gauge Higgs model on the lattice with a topological\nangle $\\theta$. The corresponding complex action problem is overcome by using a\ndual representation based on the Villain action appropriately endowed with a\n$\\theta$-term. The Villain action is interpreted as a non-compact gauge theory\nwhose center symmetry is gauged and has the advantage that the topological term\nis correctly quantized so that $2\\pi$ periodicity in $\\theta$ is intact.\nBecause of this the $\\theta = \\pi$ theory has an exact $Z_2$ charge-conjugation\nsymmetry $C$, which is spontaneously broken when the mass-squared of the\nscalars is large and positive. Lowering the mass squared the symmetry becomes\nrestored in a second order phase transition. Simulating the system at $\\theta =\n\\pi$ in its dual form we determine the corresponding critical endpoint as a\nfunction of the mass parameter. Using a finite size scaling analysis we\ndetermine the critical exponents and show that the transition is in the 2d\nIsing universality class, as expected.",
        "positive": "Unstable Modes and Confinement in the Lattice Schr\u00f6dinger Functional\n  Approach: We analyze the problem of the Nielsen-Olesen unstable modes in the SU(2)\nlattice gauge theory by means of a recently introduced gauge-invariant\neffective action. We perform numerical simulations in the case of a constant\nAbelian chromomagnetic field. We find that for lattice sizes above a certain\ncritical length the density of effective action shows a behaviour compatible\nwith the presence of the unstable modes. We put out a possible relation between\nthe dynamics of the unstable modes and the confinement."
    },
    {
        "anchor": "Remnant index theorem and low-lying eigenmodes for twisted mass fermions: We analyze the low-lying spectrum and eigenmodes of lattice Dirac operators\nwith a twisted mass term. The twist term expels the eigenvalues from a strip in\nthe complex plane and all eigenmodes obtain a non-vanishing matrix element with\ngamma-5. For a twisted Ginsparg-Wilson operator the spectrum is located on two\narcs in the complex plane. Modes due to non-trivial topological charge of the\nunderlying gauge field have their eigenvalues at the edges of these arcs and\nobey a remnant index theorem. For configurations in the confined phase we find\nthat the twist mainly affects the zero modes, while the bulk of the spectrum is\nessentially unchanged.",
        "positive": "Perturbative renormalization of $\u0394F = 2$ four-fermion operators\n  with the chirally rotated Schr\u00f6dinger functional: The chirally rotated Schr\\\"odinger functional ($\\chi$SF) renders the\nmechanism of automatic $O(a)$ improvement compatible with Schr\\\"odinger\nfunctional (SF) renormalization schemes. Here we define a family of\nrenormalization schemes based on the $\\chi$SF for a complete basis of $\\Delta F\n= 2$ parity-odd four-fermion operators. We compute the corresponding\nscale-dependent renormalization constants to one-loop order in perturbation\ntheory and obtain their NLO anomalous dimensions by matching to the\n$\\overline{\\textrm{MS}}$ scheme. Due to automatic $O(a)$ improvement, once the\n$\\chi$SF is renormalized and improved at the boundaries, the step scaling\nfunctions (SSF) of these operators approach their continuum limit with\n$O(a^{2})$ corrections without the need of operator improvement."
    },
    {
        "anchor": "Gauged Gross--Neveu model with overlap fermions: We investigate chiral properties of the overlap lattice fermion by using\nsolvable model in two dimensions, the gauged Gross-Neveu model. In this model,\nthe chiral symmetry is spontaneously broken in the presence of small but finite\nfermion mass. We calculate the quasi-Nambu-Goldstone(NG) boson mass as a\nfunction of the bare fermion mass and two parameters in the overlap formula. We\nfind that the quasi-NG boson mass has desired properties as a result of the\nextended chiral symmetry found by L\\\"uscher. We also show the PCAC relation is\nsatisfied in desired form. Comparison between the overlap and Wilson lattice\nfermions is also made.",
        "positive": "Lattice QCD on Non-Orientable Manifolds: A common problem in lattice QCD simulations on the torus is the extremely\nlong autocorrelation time of the topological charge, when one approaches the\ncontinuum limit. The reason is the suppressed tunneling between topological\nsectors. The problem can be circumvented by replacing the torus with a\ndifferent manifold, so that the connectivity of the configuration space is\nchanged. This can be achieved by using open boundary conditions on the fields,\nas proposed earlier. It has the side effect of breaking translational\ninvariance strongly. Here we propose to use a non-orientable manifold, and show\nhow to define and simulate lattice QCD on it. We demonstrate in quenched\nsimulations that this leads to a drastic reduction of the autocorrelation time.\nA feature of the new proposal is, that translational invariance is preserved up\nto exponentially small corrections. A Dirac-fermion on a non-orientable\nmanifold poses a challenge to numerical simulations: the fermion determinant\nbecomes complex. We propose two approaches to circumvent this problem."
    },
    {
        "anchor": "Higher-loop gluon and ghost propagators in Landau gauge from numerical\n  stochastic perturbation theory: We present higher loop results for the gluon and ghost propagator in Landau\ngauge on the lattice calculated in numerical stochastic perturbation theory. We\nmake predictions for the perturbative content of those propagators as function\nof the lattice momenta for finite lattices. To find out their nonperturbative\ncontributions, the logarithmic definition of the gauge fields and the\ncorresponding Faddeev-Popov operator have to be implemented in the Monte Carlo\nsimulations.",
        "positive": "Heavy two- and three-quark free energies at finite $T$: We investigate the behaviour of heavy $QQ$- and $QQQ$-free energies in SU(3)\npure gauge theory at finite temperature. After stating some general properties\nof the free energies, we discuss the $QQ$-antitriplet and -sextet channels as\nwell as free energies in different $QQQ$-channels. We perform a detailed finite\nvolume scaling analysis of $QQ$-free energies below and above $T_c$. Moreover,\nwe also discuss the relation of the $QQ$-antitriplet to the $Q\\bar Q$-singlet\nfree energies. A comparison of the effective running coupling indicates that\nthe $r$-dependence of the free energies differs by a factor of two in agreement\nwith the different Casimir factors. We observe that the baryonic free energies\ncan be decomposed into a sum of two particle interactions."
    },
    {
        "anchor": "Precise predictions of charmed-bottom hadrons from lattice QCD: We report the ground state masses of hadrons containing at least one charm\nand one bottom quark using lattice quantum chromodynamics. These include mesons\nwith spin (J)-parity (P) quantum numbers J(P): 0(-), 1(-), 1(+) and 0(+) and\nthe spin-1/2 and 3/2 baryons. Among these hadrons only the ground state of 0(-)\nis known experimentally and therefore our predictions provide important\ninformation for the experimental discovery of all other hadrons with these\nquark contents.",
        "positive": "QCD spectroscopy and quark mass renormalisation in external magnetic\n  fields with Wilson fermions: We study the change of the QCD spectrum of low-lying mesons in the presence\nof an external magnetic field using Wilson fermions in the quenched\napproximation. Motivated by qualitative differences observed in the spectra of\noverlap and Wilson fermions for large magnetic fields, we investigate the\ndependence of the additive quark mass renormalisation on the magnetic field. We\nprovide evidence that the magnetic field changes the critical quark mass both\nin the free case and on our quenched ensemble. The associated change of the\nbare quark mass with the magnetic field affects the spectrum and is relevant\nfor the magnetic field dependence of a number of related quantities. We derive\nWard identities for lattice and continuum QCD+QED from which we can extract the\ncurrent quark masses. We also report on a first test of the tuning of the quark\nmasses with the magnetic field using the current quark masses, and show that\nthis tuning resolves the qualitative discrepancy between the Wilson and overlap\nspectra."
    },
    {
        "anchor": "$K_L-K_S$ mass difference from Lattice QCD: We will report on the first full calculation of the $K_L-K_S$ mass difference\nin lattice QCD. The calculation is performed on a 2+1 flavor, domain wall\nfermion, $24^3\\times 64$ ensemble with a 329 MeV pion mass and a 575 MeV kaon\nmass. Both double penguin diagrams and disconnected diagrams are included in\nthis calculation. The calculation is made finite through the GIM mechanism by\nintroducing a 949 MeV valence charm quark. While the double penguin diagrams\ncontribute a very small fraction to the mass difference, there is a large\ncancellation between disconnected diagrams and other types of diagrams. We\nobtain the mass difference $\\Delta M_K$=$3.30(34)\\times 10^{-12}$ MeV for these\nunphysical kinematics.",
        "positive": "Chiral phase structure of three flavor QCD at vanishing baryon number\n  density: We investigate the phase structure of QCD with 3 degenerate quark flavors as\nfunction of the degenerate quark masses at vanishing baryon number density. We\nuse the Highly Improved Staggered Quarks on lattices with temporal extent\n$N_{t}=6$ and perform calculations for six values of quark masses, which in the\ncontinuum limit correspond to pion masses in the range $80~{\\rm MeV} \\lesssim\nm_{\\pi} \\lesssim 230~$MeV. By analyzing the volume and temperature dependence\nof the chiral condensate and chiral susceptibility we find no direct evidence\nfor a first order phase transition in this range of pion mass values. Relying\non the universal scaling behaviors of the chiral observables near an\nanticipated chiral critical point, we estimate an upper bound for the critical\npion mass, $m_\\pi^c \\lesssim$ 50 MeV, below which a region of first order\nchiral phase transition is favored."
    },
    {
        "anchor": "Strong dynamics with matter in multiple representations: SU(4) gauge\n  theory with fundamental and sextet fermions: We present a non-perturbative lattice study of SU(4) gauge theory with two\nflavors of fermions in the fundamental representation and two in the two-index\nantisymmetric representation: a theory closely related to a minimal\npartial-compositeness model for physics beyond the Standard Model, that was\nproposed by G. Ferretti. We discuss the phase structure of the lattice theory\nand report results for various observables of interest, including the masses of\nstates obtained from different combinations of valence fermions and the\nspectrum of the Dirac operator. Finally, we comment on the extension of this\ntype of studies to other partial-compositeness models (including, in\nparticular, one that was recently suggested by H. Gertov et al.), which could\nadmit lighter top-quark partners, highlighting some key features of our lattice\nsimulation algorithm, that make it suitable for such generalizations.",
        "positive": "Fine grinding localized updates via gauge equivariant flows in the 2D\n  Schwinger model: State-of-the-art simulations of discrete gauge theories are based on Markov\nchains with local changes in the field space, which however at very fine\nlattice spacings are notoriously difficult due to separated topological sectors\nof the gauge field. Hybrid Monte Carlo (HMC) algorithms, which are very\nefficient at coarser lattice spacings, suffer from increasing autocorrelation\ntimes. This makes simulation of lattice QCD close to the continuum infeasible\neven with exa-scale computing.\n  An approach, which can overcome long autocorrelation times, is based on\ntrivializing maps, where a new gauge proposal is given by mapping a\nconfiguration from a trivial space to the target one, distributed via the\nassociated Boltzmann factor. Using gauge equivariant coupling layers, the map\ncan be approximated via machine learning techniques. However the deviations\nscale with the volume in case of local theories and extensive distributions,\nrendering a global update unfeasible for realistic box sizes.\n  In this proceeding, we will discuss the potential of localized updates in\ncase of the 2D Schwinger Model. Using gauge-equivariant flow maps, a local\nupdate can be fine grained towards finer lattice spacing. Based on this we will\npresent results on simulating the 2D Schwinger Model with dynamical Nf=2 Wilson\nfermions at fine lattice spacings using scalable global correction steps and\ncompare the performance to the HMC."
    },
    {
        "anchor": "Current Renormalisation in NRQCD for Semi-leptonic $B\\to D$ Decays: We present a calculation of the renormalisation constants for the temporal\nvector current, $Z_{V_0}$ and spatial axial current, $Z_{A_k}$, to\n$O(\\alpha_s/M)$ for $B\\to D$ transitions using the $O(1/M)$ NRQCD action for\nboth $b$ and $c$ quarks evaluated for a large range of mass parameters.\nConsiderations for the renormalisation of the spatial vector current and the\ntemporal axial current are discussed and initial results for a mixed lattice\ncurrent are presented for the spatial vector current.",
        "positive": "Neutral kaon mixing beyond the standard model with nf=2+1 chiral\n  fermions: We compute the hadronic matrix elements of the four-quark operators needed\nfor the study of neutral kaon mixing beyond the Standard Model (SM). We use\nnf=2+1 flavours of domain-wall fermions (DWF) which exhibit good chiral-flavour\nsymmetry. The renormalization is performed non-perturbatively through the\nRI-MOM scheme and our results are converted perturbatively to MSbar. The\ncomputation is performed on a single lattice spacing a=0.086 fm with a lightest\nunitary pion mass of 290 MeV. The various systematic errors, including the\ndiscretisation effects, are estimated and discussed. Our results confirm a\nprevious quenched study, where large ratios of non-SM to SM matrix elements\nwere obtained."
    },
    {
        "anchor": "Energy dependence of nucleon-nucleon potentials: We investigate the energy dependence of potentials defined through the\nBethe-Salpeter wave functions. We analytically evaluate such a potential in the\nIsing field theory in 2 dimensions and show that its energy dependence is weak\nat low energy. We then numerically calculate the nucleon-nucleon potential at\nnon-zero energy using quenched QCD with anti-periodic boundary condition. In\nthis case we also observe that the potentials are almost identical at $E\\simeq\n0$ and $E\\simeq 50$ MeV, where $E$ is the center of mass kinetic energy.",
        "positive": "The infrared behavior of lattice QCD Green's functions: We investigate different aspects of lattice QCD in Landau gauge using Monte\nCarlo simulations. In particular, we focus on the low momentum behavior of\ngluon and ghost propagators. The gauge group is SU(3). Different systematic\neffects on the gluon and ghost propagators are studied, e.g. the dependence on\nthe choice of Gribov copies or the influence of dynamical Wilson fermions. We\ncompare our data with results from studies of Dyson-Schwinger equations for the\ngluon and ghost propagators. We demonstrate that the infrared behavior of both\npropagators, as found in this thesis, is consistent with different criteria for\nconfinement. However, the running coupling constant, given as a\nrenormalization-group-invariant combination of the gluon and ghost dressing\nfunctions, does not expose a finite infrared fixed point. We also report on a\nfirst nonperturbative computation of the SU(3) ghost-gluon-vertex\nrenormalization constant and on an investigation of the spectral properties of\nthe Faddeev-Popov operator."
    },
    {
        "anchor": "Universal critical behavior and the transition temperature in\n  (2+1)-flavor QCD: We discuss the universal critical behavior in (2+1)-flavor QCD by analyzing\nlattice data from improved staggered fermions generated by the HotQCD\nCollaboration. We present recent results from two different lattice\ndiscretizations and various lattice spacings ($N_\\tau=6,8,12$) at fixed\nphysical strange quark mass ($m_s$) but varying light quark mass ($m_l$). We\nfind that the chiral order-parameter, i.e. the chiral condensate, shows the\nexpected universal scaling that is associated with the critical point in the\nchiral limit already for light quark masses $m_l/m_s \\lsim 0.05$. From an\nanalysis of the disconnected chiral susceptibility we estimate a preliminary\nvalue of the QCD transition temperature.",
        "positive": "Lattice Calculation of QCD Vacuum Correlation Functions: The first exploratory calculations of QCD vacuum correlation functions on a\nlattice are reported. Qualitative agreement with phenomenological results is\nobtained in channels for which experimental data are available, and these\ncorrelation functions are shown to be useful in exploring approximations based\non sum rules and interacting instantons."
    },
    {
        "anchor": "Scalar QCD at nonzero density: We study scalar QCD at nonzero density in the strong coupling limit. It has a\nsign problem which looks structurally similar to the one in QCD. We show first\ndata for the reweighting factor. After introducing dual variables by\nintegrating out the SU(3) gauge links, we find that at least 3 flavors are\nneeded for a nontrivial dependence on the chemical potential. In this dual\nrepresentation there is no sign problem remaining. The dual variables are\npartially constrained, thus we propose to use a hybrid approach for the\nupdates: For unconstrained variables local updates can be used, while for\nconstrained variables using updates based on the worm algorithm is more\npromising.",
        "positive": "Check of a new non-perturbative mechanism for elementary fermion mass\n  generation: We consider a field theoretical model where a SU(2) fermion doublet,\nsubjected to non-Abelian gauge interactions, is also coupled to a complex\nscalar field doublet via a Yukawa and an irrelevant Wilson-like term. Despite\nthe presence of these two chiral breaking operators in the Lagrangian, an exact\nsymmetry acting on fermions and scalars prevents perturbative mass corrections.\nIn the phase where fermions are massless (Wigner phase) the Yukawa coupling can\nbe tuned to a critical value at which chiral transformations acting on fermions\nonly become a symmetry of the theory (up to cutoff effects). In the\nNambu-Goldstone phase of the critical theory a fermion mass term of dynamical\norigin is expected to arise in the Ward identities of the purely fermionic\nchiral transformations. Such a non-perturbative mechanism of dynamical mass\ngeneration can provide a \"natural\" (\\`a la 't Hooft) alternative to the Higgs\nmechanism adopted in the Standard Model. Here we lay down the theoretical\nframework necessary to demonstrate the existence of this mechanism by means of\nlattice simulations."
    },
    {
        "anchor": "Neutrinoless double beta decay from lattice QCD: While the discovery of non-zero neutrino masses is one of the most important\naccomplishments by physicists in the past century, it is still unknown how and\nin what form these masses arise. Lepton number-violating neutrinoless double\nbeta decay is a natural consequence of Majorana neutrinos and many BSM\ntheories, and many experimental efforts are involved in the search for these\nprocesses. Understanding how neutrinoless double beta decay would manifest in\nnuclear environments is key for understanding any observed signals. In these\nproceedings we present an overview of a set of one- and two-body matrix\nelements relevant for experimental searches for neutrinoless double beta decay,\ndescribe the role of lattice QCD calculations, and present preliminary lattice\nQCD results.",
        "positive": "Scaling region of the 3D Ising universality class in finite temperature\n  QCD: We introduce a universal combination of susceptibility and correlation length\nin the 3D Ising model, depending both on temperature and external magnetic\nfield. Starting from a parametric representation of the equation of state, we\nstudy its behaviour close to the critical point. The results we derive can be\nused as a sort of \"reference frame\" to chart the scaling region of the 3D Ising\nuniversality class. More specifically, we focus on instances of Ising behaviour\nin finite temperature QCD and, among these, we are particularly interested on\nthe critical ending point in the finite density, finite temperature QCD phase\ndiagram. In this context, Monte Carlo simulations are not possible and it is\nparticularly difficult to disentangle \"magnetic-like\" from \"thermal-like\"\nobservables, thus an explicit charting of the critical region could be useful\nfor a direct comparison of experimental results with QFT/Statmech predictions."
    },
    {
        "anchor": "Lattice formulation of chiral gauge theories: We present a general formulation of chiral gauge theories, which admits Dirac\noperators with more general spectra, reveals considerably more possibilities\nfor the structure of the chiral projections, and nevertheless allows\nappropriate realizations. In our analyses we use two forms of the correlation\nfunctions which both also apply in the presence of zero modes and for any value\nof the index. To account properly for the conditions on the bases the concept\nof equivalence classes of pairs of them is introduced. The behaviors under\ngauge transformations and under CP transformations are unambiguously derived.",
        "positive": "Monopoles and deconfinement transition in SU(2) lattice gauge theory: We investigate SU(2) lattice gauge theory in four dimensions in the maximally\nabelian projection. Studying the effects on different lattice sizes we show\nthat the deconfinement transition of the fields and the percolation transition\nof the monopole currents in the three space dimensions are precisely related.\nTo arrive properly at this result the uses of a mathematically sound\ncharacterization of the occurring networks of monopole currents and of an\nappropriate method of gauge fixing turn out to be crucial. In addition we\ninvestigate detailed features of the monopole structure in time direction."
    },
    {
        "anchor": "Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite\n  Isospin Chemical Potential: We consider the phase diagram of twisted mass Wilson fermions of two-flavor\nQCD in the parameter space of the quark mass, the isospin chemical potential,\nthe twist angle and the lattice spacing. This work extends earlier studies in\nthe continuum and those at zero chemical potential. We evaluate the phase\ndiagram as well as the spectrum of the (pseudo-)Goldstone bosons using the\nchiral Lagrangian for twisted mass Wilson fermions at non-zero isospin chemical\npotential. The phases are obtained from a mean field analysis. At zero twist\nangle we find that already an infinitesimal isospin chemical potential destroys\nthe Aoki phase. The reason is that in this phase we have massless Goldstone\nbosons with a non-zero isospin charge. At finite twist angle only two different\nphases are present, one phase which is continuously connected to the Bose\ncondensed phase at non-zero chemical potential and another phase which is\ncontinuously connected to the normal phase. For either zero or maximal twist\nthe phase diagram is more complicated as the saddle point equations allow for\nmore solutions.",
        "positive": "Semidefinite Programs at Finite Fermion Density: Semidefinite programs can be constructed to provide a non-perturbative view\nof the zero-temperature behavior of quantum systems. This paper examines the\nproperties of these semidefinite programs when applied to lattice-regulated\nfield theories exhibiting fermion sign problems. Specifically on the\nfinite-density Thirring model, there is no indication that the accuracy of\nsemidefinite programs suffers from any difficulty analogous to the sign\nproblem."
    },
    {
        "anchor": "Moments of nucleon generalized parton distributions from lattice QCD: We present results on the lower moments of the nucleon generalized parton\ndistri butions within lattice QCD using two dynamical flavors of degenerate\ntwisted mass fermions. Our simulations are performed on lattices with three\ndifferent values of the lattice spacings, namely $a=0.089$ fm, $a=0.070$ fm and\n$a=0.056$ fm, allowing the investigation of cut-off effects. The volume\ndependence is examined using simulations on two lattices of spatial length\n$L=2.1$ fm and $L=2.8$ fm. The simulations span pion masses in the range of\n260-470 MeV. Our results are renormalized non-perturbatively and the values are\ngiven in the $\\bar{\\rm MS}$ scheme at a scale $ \\mu=2$ GeV. They are chirally\nextrapolated to the physical point in order to compare with experiment. The\nconsequences of these results on the spin carried by the quarks in the nucleon\nare investigated.",
        "positive": "Monopoles and hadron spectrum in quenched QCD: We report the preliminary results of the studies of hadron spectrum under the\nbackground of abelian and monopole gauge fields in quenched Wilson SU(3) QCD.\nAbelian gauge fields alone reproduce the same chiral limit as in the full case.\nCritical hopping parameter $\\kappa_c$ and $m_{\\rho}$ are the same in both\ncases. We need more time to get a definite result in the case of monopole\nbackground. The photon contribution do not produce any mass gap in the chiral\nlimit ($\\kappa=\\kappa_c\\sim 0.17$). The behavior is similar to those in the\nfree photon case for $\\kappa_c= 0.125$."
    },
    {
        "anchor": "Observations on the Wilson fermions in the epsilon regime: We make several observations concerning the low quark mass region with Wilson\nfermions and how this is connected with the epsilon regime in the continuum. A\ntransition from tiny cutoff effects to rather large discretization errors would\ntake place in general with Wilson fermions if we lower the quark mass at finite\nlattice spacing. We argue that these two regions exhibit rather different\nbehaviours concerning the coupling between cutoff effects and zero-modes. We\ninterpolate between these two regimes adding to the continuum epsilon regime\nformulae, in the spirit of the Symanzik expansion, the relevant operators\nparametrising the leading cutoff effects. We compute the partition function,\nthe chiral condensate, scalar and pseudo-scalar correlation functions. The\nfinal formulae can be used to fit lattice data to extract physical low energy\nconstants, and to estimate systematic uncertainties coming from discretization\nerrors. Moreover they suggest ways on how to remove these cutoff effects, the\ncore of which are captured by the continuum zero modes.",
        "positive": "Universality in Random Walk Models with Birth and Death: Models of random walks are considered in which walkers are born at one\nlocation and die at all other locations with uniform death rate. Steady-state\ndistributions of random walkers exhibit dimensionally dependent critical\nbehavior as a function of the birth rate. Exact analytical results for a\nhyperspherical lattice yield a second-order phase transition with a nontrivial\ncritical exponent for all positive dimensions $D\\neq 2,~4$. Numerical studies\nof hypercubic and fractal lattices indicate that these exact results are\nuniversal. Implications for the adsorption transition of polymers at curved\ninterfaces are discussed."
    },
    {
        "anchor": "Quark masses from lattice QCD and the study of textures: I review how the determination of quark masses from lattice QCD can be used\nto study textures in quark mass matrices. This type of theory relates quark\nmasses to CKM matrix elements. I demonstrate how the recent precision results\nfrom the HPQCD and MILC collaborations for quark masses can be used to test\nsome of these ideas.",
        "positive": "The x-dependence of hadronic parton distributions: A review on the\n  progress of lattice QCD: In this article, we review recent lattice calculations on the $x$-dependence\nof parton distributions, with the latter providing information on hadron\nstructure. These calculations are based on matrix elements of boosted hadrons\ncoupled to non-local operators and can be related to the standard, light-cone\ndistribution functions via an appropriate factorization formalism. There is\nsignificant progress in several directions, including calculations of flavor\nsinglet parton distribution functions (PDFs), first calculations of generalized\nparton distributions (GPDs), as well as the implementation of some of the\napproaches for the transverse-momentum-dependent PDFs (TMD PDFs). This new\ndirection of lattice calculations is particularly interesting for\nphenomenological fits on experimental data sets, as the lattice results can\nhelp to improve the constraints on the distribution functions."
    },
    {
        "anchor": "Pion and $\u03c1$-meson form factors using four-point functions in N$_F$=2\n  QCD: Hadron wave functions and form factors can be extracted using four-point\ncorrelators. Stochastic techniques are used to estimate the all to all\npropagators, which are required for the exact calculation of four-point\nfunctions. We apply the so called one-end trick to evaluate meson four-point\nfunctions. We demonstrate the effectiveness of the technique in the case of the\npion and the $\\rho$-meson where we extract their charge distribution, as well\nas the form factors.",
        "positive": "Fermionic correlation functions from the staggered Schr\u00f6dinger\n  functional: We consider the Schr\\\"odinger functional with staggered one-component\nfermions on a fine lattice of size $(L/a)^3 \\times (T/a)$ where $T/a$ must be\nan odd number. In order to reconstruct the four-component spinors, two\ndifferent set-ups are proposed, corresponding to the coarse lattice having size\n$(L/2a)^3 \\times (T'/2a)$, with $T' = T \\pm a$. The continuum limit is then\ndefined at fixed $T'/L$. Both cases have previously been investigated in the\npure gauge theory. Here we define fermionic correlation functions and study\ntheir approach to the continuum limit at tree-level of perturbation theory."
    },
    {
        "anchor": "Lattice energy-momentum tensor with Symanzik improved actions: We define the energy-momentum tensor on lattice for the $\\lambda \\phi^4$ and\nfor the nonlinear $\\sigma$-model Symanzik tree-improved actions, using Ward\nidentities or an explicit matching procedure. The resulting operators give the\ncorrect one loop scale anomaly, and in the case of the sigma model they can\nhave applications in Monte Carlo simulations.",
        "positive": "Spontaneous chiral-symmetry breaking of lattice QCD with massless\n  dynamical quarks: One of the most challenging issues in QCD is the investigation of spontaneous\nchiral-symmetry breaking, which is characterized by the non-vanishing chiral\ncondensate when the bare fermion mass is zero. In standard methods, one has to\nperform expensive lattice simulations at multiple bare quark masses, and employ\nsome modeled function to extrapolate the data to the chiral limit. This paper\napplies the probability distribution function method to computing the chiral\ncondensate in lattice QCD with massless dynamical quarks, without any ambiguous\nmass extrapolation. The results for staggered quarks indicates that the method\nmight be a more efficient alternative for investigating the spontaneous\nchiral-symmetry breaking in lattice QCD."
    },
    {
        "anchor": "Gross-Neveu model with Borici-Creutz fermion: We investigate the chiral phase structure of the Gross-Neveu model on a 2-D\nlattice using the Borici-Creutz fermion action. We present a strong coupling\nanalysis of the Gross-Neveu model and perform a hybrid Monte Carlo simulation\nof the model with Borici-Creutz fermions. Both analytic and lattice results\nshow a second order chiral phase transition.",
        "positive": "Hybrid meson decay from the lattice: We discuss the allowed decays of a hybrid meson in the heavy quark limit. We\ndeduce that an important decay will be into a heavy quark non-hybrid state and\na light quark meson, in other words, the de-excitation of an excited gluonic\nstring by emission of a light quark-antiquark pair.\n  We discuss the study of hadronic decays from the lattice in the heavy quark\nlimit and apply this approach to explore the transitions from a spin-exotic\nhybrid to $\\chi_b \\eta$ and $\\chi_b S$ where $S$ is a scalar meson. We obtain a\nsignal for the transition emitting a scalar meson and we discuss the\nphenomenological implications."
    },
    {
        "anchor": "String Breaking in Non-Abelian Gauge Theories with Fundamental Matter\n  Fields: We present clear numerical evidence for string breaking in three-dimensional\nSU(2) gauge theory with fundamental bosonic matter through a mixing analysis\nbetween Wilson loops and meson operators representing bound states of a static\nsource and a dynamical scalar. The breaking scale is calculated in the\ncontinuum limit. In units of the lightest glueball we find $r_{\\rm b}\nm_G\\approx13.6$. The implications of our results for QCD are discussed.",
        "positive": "Hamiltonian lattice QCD at finite chemical potential: At sufficiently high temperature and density, quantum chromodynamics (QCD) is\nexpected to undergo a phase transition from the confined phase to the\nquark-gluon plasma phase. In the Lagrangian lattice formulation the Monte Carlo\nmethod works well for QCD at finite temperature, however, it breaks down at\nfinite chemical potential. We develop a Hamiltonian approach to lattice QCD at\nfinite chemical potential and solve it in the case of free quarks and in the\nstrong coupling limit. At zero temperature, we calculate the vacuum energy,\nchiral condensate, quark number density and its susceptibility, as well as mass\nof the pseudoscalar, vector mesons and nucleon. We find that the chiral phase\ntransition is of first order, and the critical chemical potential is $\\mu_C\n=m_{dyn}^{(0)}$ (dynamical quark mass at $\\mu=0$). This is consistent with\n$\\mu_C \\approx M_N^{(0)}/3$ (where $M_N^{(0)}$ is the nucleon mass at $\\mu=0$)."
    },
    {
        "anchor": "Electric-magnetic asymmetry of the A^2 condensate and the phases of\n  Yang-Mills theory: We study the finite-temperature behavior of the A^2 condensate in the Landau\ngauge of SU(2) Yang--Mills theory on the lattice in a wide range of\ntemperatures. The asymmetry between the electric (temporal) and magnetic\n(spatial) components of this unconventional dimension-2 condensate is a\nconvenient ultraviolet-finite quantity which possesses, as we demonstrate,\nunexpected properties. The low-temperature behavior of the condensate asymmetry\nsuggests that the mass of the lowest thermal excitation in the condensate is\nunexpectedly low, about 200 MeV, which is much smaller than the glueball mass.\nThe asymmetry is peaking at the phase transition, becoming a monotonically\ndecreasing function in the deconfinement phase. A symmetric point is reached in\nthe deconfinement phase at a temperature approximately equal twice the critical\ntemperature. The behavior of the electric-magnetic asymmetry of the condensate\nseparates the phase diagram of Yang-Mills theory into three regions. We suggest\nthat these regions are associated with the condensed, liquid and gaseous states\nof the confining gluonic objects, the Abelian monopoles.",
        "positive": "A Study of the Bulk Phase Transitions of the SU(2) Lattice Gauge Theory\n  with Mixed Action: Using the finite size scaling theory, we re-examine the nature of the bulk\nphase transition in the fundamental-adjoint coupling plane of the SU(2) lattice\ngauge theory at $\\beta_A = 1.25$ where previous finite size scaling\ninvestigations of the deconfinement phase transition showed it to be of first\norder for temporal lattices with four sites. Our simulations on $N^4$ lattices\nwith N=6, 8, 10, 12 and 16 show an absence of a first order bulk phase\ntransition. We find the discontinuity in the average plaquette to decrease\napproximately linearly with $N$. Correspondingly, the plaquette susceptibility\ngrows a lot slower with the 4-volume of the lattice than expected from a first\norder bulk phase transition."
    },
    {
        "anchor": "Applying recursive numerical integration techniques for solving high\n  dimensional integrals: The error scaling for Markov-Chain Monte Carlo techniques (MCMC) with $N$\nsamples behaves like $1/\\sqrt{N}$. This scaling makes it often very time\nintensive to reduce the error of computed observables, in particular for\napplications in lattice QCD. It is therefore highly desirable to have\nalternative methods at hand which show an improved error scaling. One candidate\nfor such an alternative integration technique is the method of recursive\nnumerical integration (RNI). The basic idea of this method is to use an\nefficient low-dimensional quadrature rule (usually of Gaussian type) and apply\nit iteratively to integrate over high-dimensional observables and Boltzmann\nweights. We present the application of such an algorithm to the topological\nrotor and the anharmonic oscillator and compare the error scaling to MCMC\nresults. In particular, we demonstrate that the RNI technique shows an error\nscaling in the number of integration points $m$ that is at least exponential.",
        "positive": "Level spacings of parametric chiral random matrices and two-color QCD\n  with twisted boundary condition: We evaluate level spacing and smallest eigenvalue distributions of chiral\nrandom matrix ensembles transiting from symplectic or orthogonal to unitary\nsymmetry classes with a crossover parameter rho. As expected from the effective\nsigma model description, these results can be fitted perfectly to the\nfundamental or adjoint staggered Dirac spectrum of SU(2) quenched lattice gauge\ntheory under the imaginary chemical potential (twisting) mu. The linear\ndependence of the parameter rho on mu determines the pion decay constant F as\nits proportionality constant."
    },
    {
        "anchor": "Chiral Fermions on the Lattice: An expression for the lattice effective action induced by chiral fermions in\nany even dimensions in terms of an overlap of two states is shown to have\npromising properties in two dimensions: The correct abelian anomaly is\nreproduced and instantons are suppressed.",
        "positive": "Critical phenomena and renormalization-group flow of multi-parameter\n  \u03a6^4 field theories: In the framework of the renormalization-group (RG) approach, critical\nphenomena can be investigated by studying the RG flow of multi-parameter\n$\\Phi^4$ field theories with an $N$-component fundamental field, containing up\nto 4th-order polynomials of the field. Some physically interesting systems\nrequire $\\Phi^4$ field theories with several quadratic and quartic parameters,\ndepending essentially on their symmetry and symmetry-breaking pattern at the\ntransition. Results for their RG flow apply to disorder and/or frustrated\nsystems, anisotropic magnetic systems, density wave models, competing orderings\ngiving rise to multicritical behaviors. The general properties of the RG flow\nin multi-parameter $\\Phi^4$ field theories are discussed. An overview of\nfield-theoretical results for some physically interesting cases is presented,\nand compared with other theoretical approaches and experiments. Finally, this\nRG approach is applied to investigate the nature of the finite-temperature\ntransition of QCD with $N_f$ light quarks."
    },
    {
        "anchor": "On the Correct Convergence of Complex Langevin Simulations for\n  Polynomial Actions: There are problems in physics and particularly in field theory which are\ndefined by complex valued weight functions $e^{-S}$ where $S$ is a polynomial\naction $S: R^n \\rightarrow C $. The conditions under which a convergent complex\nLangevin calculation correctly simulates such integrals are discussed. All\nconditions on the process which are used to prove proper convergence are\ndefined in the stationary limit.",
        "positive": "Adjoint fermions at large-N on the lattice: Lattice simulations of Yang-Mills theories coupled with $N_f$ flavours of\nfermions in the adjoint representation provide a way to probe the\nnon-perturbative regime of a plethora of different physical scenarios, such as\nSupersymmetric Yang-Mills theory to BSM models. We are interested in the\nlarge-$N_c$ limit of these theories, for which standard lattice techniques are\nlimited by high-computational costs. Our approach makes use of the\nwell-established twisted volume reduction, which allows one to simulate these\ntheories on a $1^4$ lattice. In this talk, we are going to present a detailed\nstudy of the scale setting of these theories, performed with Wilson flow\ntechniques, but endowed with a procedure that allowed us to reduce\nfinite-volume (finite $N_c$) systematic effects. We will apply this procedure\nto our configurations for $N_f=0,\\frac{1}{2},1,2$ and analyze the dependence of\nthe scale on the coupling, the adjoint fermion mass and the number of flavours.\nFor the cases in which enough couplings are available we compared the resulting\n$\\beta$-function with the predictions of perturbation theory, finding very good\nagreement."
    },
    {
        "anchor": "Distribution of fermionic and topological observables on the lattice: We analyze the topological and fermionic vacuum structure of four-dimensional\nQCD on the lattice by means of correlators of fermionic observables and\ntopological densities. We show the existence of strong local correlations\nbetween the topological charge and monopole density on the one side and the\nquark condensate, charge and chiral density on the other side. Visualization of\nindividual gauge configurations demonstrates that instantons (antiinstantons)\ncarry positive (negative) chirality, whereas the quark charge density\nfluctuates in sign within instantons.",
        "positive": "Diquark properties from lattice QCD: It has been argued recently that diquarks, a pair of quarks in the\nanti-triplet representation of SU(3) color, are important building blocks of\nbaryons. The assumption that the scalar diquark is tightly bound seems to be\nnicely accommodated by experimental data. In this paper I attempt to extract\nphenomenological properties of diquarks from lattice QCD calculations. In\nparticular, I use the MILC 2+1 dynamical fermion lattices with domain wall\nfermion valence quarks to probe diquarks very close to the chiral limit."
    },
    {
        "anchor": "Absence of correlations in the QCD Dirac spectrum at high temperature: I propose a simple model of the distribution of the small eigenvalues of the\nQCD Dirac operator well above the finite temperature phase transition where\nchiral symmetry is restored and the spectral density at zero vanishes. Assuming\nthe absence of correlations between different regions of the low lying spectrum\nI derive analytic formulas for the distribution of the first two eigenvalues. I\nfind good agreement with data obtained using the overlap Dirac operator in\nquenched SU(2) lattice simulations. This suggests that if chiral symmetry is\nrestored spectral correlations are not important and all the statistical\nproperties of the spectrum are encoded in the spectral density.",
        "positive": "An application of the UV-filtering preconditioner to the Polynomial\n  Hybrid Monte Carlo algorithm: We apply the UV-filtering preconditioner, previously used to improve the\nMulti-Boson algorithm, to the Polynomial Hybrid Monte Carlo (UV-PHMC)\nalgorithm. The performance test for the algorithm is given for the plaquette\ngauge action and the $O(a)$-improved Wilson action at $\\beta=5.2,\nc_{\\mathrm{sw}}=2.02, M_{\\pi}/M_{\\rho}\\sim 0.8$ and 0.7 on a $16^3\\times 48$\nlattice. We find that the UV-filtering reduces the magnitude of the molecular\ndynamics force from the pseudo fermion by a factor 3 by tuning the UV-filter\nparameter. Combining with the multi-time scale molecular dynamics integrator we\nachieve a factor 2 improvement."
    },
    {
        "anchor": "Structure of logarithmically divergent one-loop lattice Feynman\n  integrals: For logarithmically divergent one-loop lattice Feynman integrals I(p,a),\nsubject to mild general conditions, we prove the following expected and crucial\nstructural result: I(p,a) = f(p)log(aM)+g(p)+h(p,M) up to terms which vanish\nfor lattice spacing a -> 0. Here p denotes collectively the external momenta\nand M is a mass scale which may be chosen arbitrarily. The f(p) and h(p,M) are\nshown to be universal and coincide with analogous quantities in the\ncorresponding continuum integral when the latter is regularized either by\nmomentum cut-off or dimensional regularization. The non-universal term g(p) is\nshown to be a homogeneous polynomial in p of the same degree as f(p). This\nstructure is essential for consistency between renormalized lattice and\ncontinuum formulations of QCD at one loop.",
        "positive": "Simulating quantum field theory with a quantum computer: Forthcoming exascale digital computers will further advance our knowledge of\nquantum chromodynamics, but formidable challenges will remain. In particular,\nEuclidean Monte Carlo methods are not well suited for studying real-time\nevolution in hadronic collisions, or the properties of hadronic matter at\nnonzero temperature and chemical potential. Digital computers may never be able\nto achieve accurate simulations of such phenomena in QCD and other\nstrongly-coupled field theories; quantum computers will do so eventually,\nthough I'm not sure when. Progress toward quantum simulation of quantum field\ntheory will require the collaborative efforts of quantumists and field\ntheorists, and though the physics payoff may still be far away, it's worthwhile\nto get started now. Today's research can hasten the arrival of a new era in\nwhich quantum simulation fuels rapid progress in fundamental physics."
    },
    {
        "anchor": "Localized eigenmodes of the overlap operator and their impact on the\n  eigenvalue distribution: In a system where chiral symmetry is spontaneously broken, the low energy\neigenmodes of the continuum Dirac operator are extended. On the lattice, due to\ndiscretization effects, the Dirac operator can have localized eigenmodes that\naffect physical quantities sensitive to chiral symmetry. While the infrared\neigenmodes of the Wilson Dirac operator are usually extended even on coarse\nlattices, the chiral overlap operator has many localized eigenmodes in the\nphysical region, especially in mixed action simulations. Depending on their\ndensity, these modes can introduce strong lattice artifacts. The effect can be\ncontrolled by changing the parameters of the overlap operator, in particular\nthe clover improvement term and the center of the overlap projection.",
        "positive": "An Update on Distribution Amplitudes of the Nucleon and its Parity\n  Partner: The calculation of baryon wave functions at small inter-quark separations is\nan ongoing effort within the QCDSF collaboration. In this update on\nnormalization constants and distribution amplitudes of the nucleon and its\nnegative parity partner, N* (1535), we present new lattice data which helps us\ncontrolling finite size effects. We use new chiral perturbation theory results\nto perform the extrapolation to the physical point."
    },
    {
        "anchor": "Signal/noise enhancement strategies for stochastically estimated\n  correlation functions: We develop strategies for enhancing the signal/noise ratio for stochastically\nsampled correlation functions. The techniques are general and offer a wide\nrange of applicability. We demonstrate the potential of the approach with a\ngeneric two-state system, and then explore the practical applicability of the\nmethod for single hadron correlators in lattice quantum chromodynamics. In the\nlatter case, we determine the ground state energies of the pion, proton, and\ndelta baryon, as well as the ground and first excited state energy of the rho\nmeson using matrices of correlators computed on an exemplary ensemble of\nanisotropic gauge configurations. In the majority of cases, we find a modest\nreduction in the statistical uncertainties on extracted energies compared to\nconventional variational techniques. However, in the case of the delta baryon,\nwe achieve a factor of three reduction in statistical uncertainties. The\nvariety of outcomes achieved for single hadron correlators illustrates an\ninherent dependence of the method on the properties of the system under\nconsideration and the operator basis from which the correlators are\nconstructed.",
        "positive": "Color Confinement in lattice Landau gauge with unquenched Wilson and KS\n  fermions: The Kugo-Ojima confinement criterion is verified in the unquenched Landau\ngauge QCD simulation. The valence quark propagator of the Kogut-Susskind\nfermion with use of the fermion action including the Naik term and the staple\ncontribution is calculated on MILC Asqtad unquenched gauge configurations, and\nit shows infrared suppression of the quark propagator."
    },
    {
        "anchor": "Progress on the Microscopic Spectrum of the Dirac Operator for QCD with\n  Wilson Fermions: Starting from the chiral Lagrangian for Wilson fermions at nonzero lattice\nspacing we have obtained compact expressions for all spectral correlation\nfunctions of the Hermitian Wilson Dirac operator in the $\\epsilon$-domain of\nQCD with dynamical quarks. We have also obtained the distribution of the\nchiralities over the real eigenvalues of the Wilson Dirac operator for any\nnumber of flavors. All results have been derived for a fixed index of the Dirac\noperator. An important effect of dynamical quarks is that they completely\nsuppress the inverse square root singularity in the spectral density of the\nHermitian Wilson Dirac operator. The analytical results are given in terms of\nan integral over a diffusion kernel for which the square of the lattice spacing\nplays the role of time. This approach greatly simplifies the expressions which\nwe here reduce to the evaluation of two-dimensional integrals.",
        "positive": "Calculating Quark Number Susceptibilities with Domain-Wall Fermions: We present results from calculations of different quark number and hadronic\nsusceptibilities on 2+1-flavor dynamical domain wall ensembles. We find that\nthe iso-spin and electric charge susceptibilities are especially well suited to\ndetermine the transition temperature, as these quantities show only small\nstatistical errors. Moreover, the transition values of the coupling obtained\nfrom iso-spin and electrical charge susceptibilities are in good agreement with\nthe one obtained from the chiral condensate."
    },
    {
        "anchor": "Bottom baryons from a dynamical lattice QCD simulation: Bottom baryon masses are calculated based on a 2+1 flavor dynamical lattice\nQCD simulation. The gauge field configurations were computed by the CP-PACS and\nJLQCD collaborations using an improved clover action. The bottom quark is\ndescribed using lattice NRQCD. Results are presented for single and double-b\nbaryons at one lattice spacing. Comparison with experimental values is\ndiscussed.",
        "positive": "Scaling of the critical temperature and quark potential with a\n  renormalization group improved SU(3) gauge action: We study the scaling property of the ratio of the critical temperature $T_c$\nto the square root of the string tension $\\sigma$ in the SU(3) pure gauge\ntheory using a renormalization group improved action. We first determine the\ncritical coupling $\\beta_c$ on lattices with temporal extension $N_t=4$ and 6,\nand then calculate the static quark potential at the critical couplings on\nlattices at zero temperature. The values of $T_{c}/\\sqrt{\\sigma}$ in the\ninfinite volume limit are identical within errors, while they are slightly\nlarger than the value extrapolated to the continuum limit with the standard\naction. We also note that the rotational invariance of the static quark\npotential is remarkably restored in the both cases, and that the potential\n$V(R)$ in physical units scales in the whole region of $R$ investigated."
    },
    {
        "anchor": "Dynamics of the Scalar Condensate in thermal 4D self-interacting Scalar\n  Field Theory on the Lattice: We simulate a four dimensional self-interacting scalar field theory on the\nlattice at finite temperature. By varying temperature, the system undergoes a\nphase transition from broken phase to symmetric phase. Our data show that the\nzero-momentum field renormalization increases by approaching critical\ntemperature. On the other hand, finite-momentum wave-function renormalization\nremains remarkably constant.",
        "positive": "Chiral extrapolations for nucleon electric charge radii: Lattice simulations for the electromagnetic form factors of the nucleon yield\ninsights into the internal structure of hadrons. The logarithmic divergence of\nthe charge radius in the chiral limit poses an interesting challenge in\nachieving reliable predictions from finite-volume lattice simulations. Recent\nresults near the physical pion mass are examined in order to confront the issue\nof how the chiral regime is approached. The electric charge radius of the\nnucleon presents a forum for achieving consistent finite-volume corrections.\nNewly-developed techniques within the framework of chiral effective field\ntheory are used to achieve a robust extrapolation of the electric charge radius\nto the physical pion mass, and to infinite volume. The chiral extrapolations\nexhibit considerable finite-volume dependence; lattice box sizes of L > 7 fm\nare required in order to achieve a direct lattice simulation result within 2%\nof the infinite-volume value at the physical point. Predictions of the\nvolume-dependence are provided to guide the interpretation of future lattice\nresults."
    },
    {
        "anchor": "Phase transitions in strongly coupled 3d Z(N) lattice gauge theories at\n  finite temperature: We perform an analytical and numerical study of the phase transitions in\nthree-dimensional Z(N) lattice gauge theories at finite temperature for N>4\nexploiting equivalence of these models with a generalized version of the\ntwo-dimensional vector Potts models in the limit of vanishing spatial coupling.\nIn this limit the Polyakov loops play the role of Z(N) spins. The effective\ncouplings of these two-dimensional spin models are calculated explicitly. It is\nargued that the effective spin models have two phase transitions of BKT type.\nThis is confirmed by large-scale Monte Carlo simulations. Using a cluster\nalgorithm we locate the position of the critical points and study the critical\nbehavior across both phase transitions in details. In particular, we determine\nvarious critical indices, compute the helicity modulus, the average action and\nthe specific heat. A scaling formula for the critical points with N is\nproposed.",
        "positive": "Confinement/deconfinement phase transition and dual Meissner effect in\n  SU(3) Yang-Mills theory: We investigate the confinement-deconfinement phase transition at finite\ntemperature of the SU(3) Yang-Mills(YM) theory on the lattice from a viewpoint\nof the dual superconductor picture based on the novel reformulation of the YM\ntheory. In particular, we compare the conventional Abelian dual superconductor\npicture with the non-Abelian dual superconductor picture proposed in our\nprevious works as the mechanism of quark confinement in the SU(3) YM theory.\nFor the SU(3) YM theory, the reformulation allows two possible options called\nmaximal and minimal. The maximal option corresponds to the manifestly\ngauge-invariant extension of the Abelian projection scheme, while the minimal\noption is really new to give the non-Abelian dual superconductor picture.\nKeeping these differences in mind, we present the numerical evidences that the\nconfinement/deconfinement phase transition is caused by\nappearance/disappearance of the dual Meissner effects. First, we measure the\nPolyakov loop average at various temperatures to determine the critical\ntemperature separating the low-temperature confined phase and the\nhigh-temperature deconfined phase. Second, we measure the static\nquark-antiquark potential. Third, we measure the chromoelectric and\nchromomagnetic flux created by a pair of quark and antiquark at temperatures\nbelow and above the critical temperature. We observe no more squeezing of the\nchromoelectric flux tube above the critical temperature. Finally, we measure\nthe associated magnetic--monopole current induced around the chromo-flux tube\nand observe that the confinement/deconfinement phase transition is associated\nwith the appearance/disappearance of the induced magnetic--monopole current,\nrespectively. We confirm that these results are also obtained by the restricted\nfield alone in both options, indicating the restricted field dominance in quark\nconfinement at finite temperature."
    },
    {
        "anchor": "Closed flux tubes and their string description in D=3+1 SU(N) gauge\n  theories: We calculate the energy spectrum of a confining flux tube that is closed\naround a spatial torus, as a function of its length l. We do so for various\nSU(N) gauge theories in 3+1 dimensions, and for various values of spin, parity\nand longitudinal momentum. We are able to present usefully accurate results for\nabout 20 of the lightest such states, for a range of l that begins close to the\n(finite volume) deconfining phase transition, and extends up to l.sqrt(K)~6\n(where K is the string tension). We find that most of these low-lying states\nare well described by the spectrum of the Nambu-Goto free string theory in flat\nspace-time. Remarkably, this is so not only at the larger values of l, where\nthe gap between the ground state energy and the low-lying excitations becomes\nsmall compared to the mass gap, but also down to much shorter lengths where\nthese excitation energies become large compared to sqrt(K), the flux-tube no\nlonger `looks' anything like a thin string, and an expansion of the effective\nstring action in powers of 1/l no longer converges. All this is for flux in the\nfundamental representation. We also calculate the k=2 (anti)symmetric ground\nstates and these show larger corrections at small l. So far all this closely\nresembles our earlier findings in 2+1 dimensions. However, and in contrast to\nthe situation in D=2+1, we also find that there are some states, with J,P=0,-\nquantum numbers, that show large deviations from the Nambu-Goto spectrum. We\ninvestigate the possibility that (some of) these states may encode the massive\nmodes associated with the internal structure of the flux tube, and we discuss\nhow the precocious free string behaviour of most states constrains the\neffective string action, on which much interesting theoretical progress has\nrecently been made.",
        "positive": "Renormalization group flow of SU(3) lattice gauge theory - Numerical\n  studies in a two coupling space: We investigate the renormalization group (RG) flow of SU(3) lattice gauge\ntheory in a two coupling space with couplings $\\beta_{11}$ and $\\beta_{12}$\ncorresponding to $1\\times 1$ and $1\\times 2$ loops respectively. Extensive\nnumerical calculations of the RG flow are made in the fourth quadrant of this\ncoupling space, i.e., $\\beta_{11}>0$ and $\\beta_{12}<0$. Swendsen's factor two\nblocking and the Schwinger-Dyson method are used to find an effective action\nfor the blocked gauge field. The resulting renormalization group flow runs\nquickly towards an attractive stream which has an approximate line shape. This\nis numerical evidence of a renormalized trajectory which locates close to the\ntwo coupling space. A model flow equation which incorporates a marginal\ncoupling (asymptotic scaling term), an irrelevant coupling and a\nnon-perturbative attraction towards the strong coupling limit reproduces\nqualitatively the observed features. We further examine the scaling properties\nof an action which is closer to the attractive stream than the currently used\nimproved actions. It is found that this action shows excellent restoration of\nrotational symmetry even for coarse lattices with $a \\sim 0.3$ fm."
    },
    {
        "anchor": "Light meson form factors in N_f=2+1 QCD with dynamical overlap quarks: We report on our calculation of pion and kaon form factors in three-flavor\nQCD using the overlap quark action. Gauge ensembles are generated on a 16^3\n\\times 48 lattice at a lattice spacing of 0.11 fm with pion masses down to 310\nMeV. Connected and disconnected meson correaltors are calculated using the\nall-to-all quark propagator. We present our preliminary analysis on the chiral\nbehavior of the electromagnetic and scalar form factors as well as a comparison\nof the shape of the K to pi form factors with experiment.",
        "positive": "Lorentz gauge and Gribov ambiguity in the compact lattice U(1) theory: The Gribov ambiguity problem is studied for compact U(1) lattice theory\nwithin the Lorentz gauge. In the Coulomb phase, it is shown that apart from\ndouble Dirac sheets all gauge (i.e. Gribov) copies originate mainly from the\nzero-momentum modes of the gauge fields. The removal of the zero-momentum modes\nturns out to be necessary for reaching the absolute maximum of the gauge\nfunctional $F(\\theta)$. A new gauge fixing procedure - zero-momentum Lorentz\ngauge - is proposed."
    },
    {
        "anchor": "Slope and curvature of the hadron vacuum polarization at vanishing\n  virtuality from lattice QCD: We compute the slope and curvature, at vanishing four-momentum transfer\nsquared, of the leading order hadron vacuum polarization function, using\nlattice QCD. Calculations are performed with 2+1+1 flavors of staggered\nfermions directly at the physical values of the quark masses and in volumes of\nlinear extent larger than 6fm. The continuum limit is carried out using six\ndifferent lattice spacings. All connected and disconnected contributions are\ncalculated, up to and including those of the charm.",
        "positive": "Nuclear Transition in the Strong Coupling Limit: Lattice QCD at finite baryon chemical potential has the infamous sign problem\nwhich hinders Monte Carlo simulations. This can be remedied by a dual\nrepresentation that makes the sign problem mild. In the strong coupling limit,\nthe dual formulation with staggered quarks is well established. We have used\nthis formulation to study the quark mass dependence of the baryon mass and the\nnuclear transition. This allows us to quantify the nuclear interaction. We have\nalso compared our Monte Carlo results with mean field predictions."
    },
    {
        "anchor": "SO(N) gauge theories in 2+1 dimensions: glueball spectra and confinement: We calculate the spectrum of light glueballs and the string tension in a\nnumber of SO(N) lattice gauge theories in 2+1 dimensions, with N in the range\nfrom N=3 to N=16. After extrapolating to the continuum limit and then to N=oo\nwe compare to the spectrum and string tension of the SU(N=oo) gauge theory and\nfind that the most reliably and precisely calculated physical quantities are\nconsistent in that limit. We also compare the glueball spectra of those pairs\nof SO(N) and SU(N') theories that possess the same Lie algebra, i.e. SO(3) and\nSU(2), SO(4) and SU(2)xSU(2), SO(6) and SU(4), and find that for the very\nlightest glueballs the spectra are consistent within each such pair, as are the\nstring tensions and the couplings. Where there are apparent discrepancies they\nare typically for heavier glueballs, where the systematic errors are much\nharder to control. We calculate the SO(N) string tensions with a particular\nfocus on the confining properties of SO(2N+1) theories which, unlike SO(2N)\ntheories, possess a trivial centre. We find that for both the light glueballs\nand for the string tension SO(2N) and SO(2N+1) gauge theories appear to form a\nsingle smooth sequence.",
        "positive": "Massless QED_3 with explicit fermions: We study dynamical mass generation in QED in (2+1) dimensions using\nHamiltonian lattice methods. We use staggered fermions, and perform simulations\nwith explicit dynamical fermions in the chiral limit. We demonstrate that a\nrecently developed method to reduce the fermion sign problem can successfully\nbe applied to this problem. Our results are in agreement with both the strong\ncoupling expansion and with Euclidean lattice simulations."
    },
    {
        "anchor": "Quark mass dependence of Spin-Orbit force in parity-odd NN system from\n  2+1 flavor QCD: We report our recent study of spin-orbit force between two nucleons in the\nparity-odd sector from lattice QCD. To examine the quark mass dependence of\nspin-orbit force, we construct it from Nambu-Bethe-Salpeter wave functions in\n$^3P_0$, $^3P_1$ and $^3P_2-^3F_2$ channels calculated from lattice QCD in the\nquark mass region $m_\\pi$=702-411 MeV. The calculation is performed on Blue\nGene/Q at KEK by using $N_f=2+1$ PACS-CS gauge configuration generated by O(a)\nimproved Wilson quark action with RG improved (Iwasaki) gauge action. We find\nthat the potentials tend to become stronger as the quark mass decreases.",
        "positive": "Two-colour QCD phases and the topology at low temperature and high\n  density: We delineate equilibrium phase structure and topological charge distribution\nof dense two-colour QCD at low temperature by using a lattice simulation with\ntwo-flavour Wilson fermions that has a chemical potential $\\mu$ and a diquark\nsource $j$ incorporated. We systematically measure the diquark condensate, the\nPolyakov loop, the quark number density and the chiral condensate with improved\naccuracy and $j\\to0$ extrapolation over earlier publications; the known\nqualitative features of the low temperature phase diagram, which is composed of\nthe hadronic, Bose-Einstein condensed (BEC) and BCS phases, are reproduced. In\naddition, we newly find that around the boundary between the hadronic and BEC\nphases, nonzero quark number density occurs even in the hadronic phase in\ncontrast to the prediction of the chiral perturbation theory (ChPT), while the\ndiquark condensate approaches zero in a manner that is consistent with the ChPT\nprediction. At the highest $\\mu$, which is of order the inverse of the lattice\nspacing, all the above observables change drastically, which implies a lattice\nartifact. Finally, at temperature of order $0.45T_c$, where $T_c$ is the chiral\ntransition temperature at zero chemical potential, the topological\nsusceptibility is calculated from a gradient-flow method and found to be almost\nconstant for all the values of $\\mu$ ranging from the hadronic to BCS phase.\nThis is a contrast to the case of $0.89T_c$ in which the topological\nsusceptibility becomes small as the hadronic phase changes into the quark-gluon\nplasma phase."
    },
    {
        "anchor": "A method for resummation of perturbative series based on the stochastic\n  solution of Schwinger-Dyson equations: We propose a numerical method for resummation of perturbative series, which\nis based on the stochastic perturbative solution of Schwinger-Dyson equations.\nThe method stochastically estimates the coefficients of perturbative series,\nand incorporates Borel resummation in a natural way. Similarly to the \"worm\"\nalgorithm, the method samples open Feynman diagrams, but with an arbitrary\nnumber of external legs. As a test of our numerical algorithm, we study the\nscale dependence of the renormalized coupling constant in a theory of\none-component scalar field with quartic interaction. We confirm the triviality\nof this theory in four and five space-time dimensions, and the instability of\nthe trivial fixed point in three dimensions.",
        "positive": "Confinement, deconfinement and the photon propagator in 3D cQED on the\n  lattice: We report on a lattice study of the gauge boson propagator of 3D compact QED\nin Landau gauge at zero and finite temperature. Non-perturbative effects are\nreflected by the generation of a mass m and by an anomalous dimension alpha.\nThese effects can be attributed to monopoles and are absent in the propagator\nof the regular part of the gauge field."
    },
    {
        "anchor": "Proton and neutron electromagnetic form factors from lattice QCD: The electromagnetic form factors of the proton and the neutron are computed\nwithin lattice QCD using simulations with quarks masses fixed to their physical\nvalues. Both connected and disconnected contributions are computed. We analyze\ntwo new ensembles of $N_f = 2$ and $N_f = 2 + 1 + 1$ twisted mass\nclover-improved fermions and determine the proton and neutron form factors, the\nelectric and magnetic radii, and the magnetic moments. We use several values of\nthe sink-source time separation in the range of 1.0 fm to 1.6 fm to ensure\nground state identification. Disconnected contributions are calculated to an\nunprecedented accuracy at the physical point. Although they constitute a small\ncorrection, they are non-negligible and contribute up to 15% for the case of\nthe neutron electric charge radius.",
        "positive": "A study of the N to Delta transition form factors in full QCD: The N to Delta transition form factors GM1, GE2 and GC2 are evaluated using\ndynamical MILC configurations and valence domain wall fermions at three values\nof quark mass corresponding to pion mass 606 MeV, 502 MeV and 364 MeV on\nlattices of spatial size $20^3$ and $28^3$. The unquenched results are compared\nto those obtained at similar pion mass in the quenched theory."
    },
    {
        "anchor": "Topological tunneling with Dynamical overlap fermions: Tunneling between different topological sectors with dynamical chiral\nfermions is difficult because of a poor mass scaling of the pseudo-fermion\nestimate of the determinant. For small fermion masses it is virtually\nimpossible using standard methods. However, by projecting out the small Wilson\neigenvectors from the overlap operator, and treating the correction determinant\nexactly, we can significantly increase the rate of topological sector tunneling\nand reduce substantially the auto-correlation time. We present and compare a\nnumber of different approaches, and advocate a method which allows topological\ntunneling even at low mass with little addition to the computational cost.",
        "positive": "Thermodynamics of strong interaction matter from lattice QCD and the\n  hadron resonance gas model: We compare recent lattice QCD calculations of higher order cumulants of\nnet-strangeness fluctuations with hadron resonance gas (HRG) model\ncalculations. Up to the QCD transition temperature Tc=( 154 +/- 9) MeV we find\ngood agreement between QCD and HRG model calculations of second and fourth\norder cumulants, even when subtle aspects of net-baryon number, strangeness and\nelectric charge fluctuations are probed. In particular, the fourth order\ncumulants indicate that also in the strangeness sector of QCD the failure of\nHRG model calculations sets in quite abruptly in the vicinity of the QCD\ntransition temperature and is apparent in most observables for T > 160 MeV."
    },
    {
        "anchor": "Fourier-Flow model generating Feynman paths: As an alternative but unified and more fundamental description for quantum\nphysics, Feynman path integrals generalize the classical action principle to a\nprobabilistic perspective, under which the physical observables' estimation\ntranslates into a weighted sum over all possible paths. The underlying\ndifficulty is to tackle the whole path manifold from finite samples that can\neffectively represent the Feynman propagator dictated probability distribution.\nModern generative models in machine learning can handle learning and\nrepresenting probability distribution with high computational efficiency. In\nthis study, we propose a Fourier-flow generative model to simulate the Feynman\npropagator and generate paths for quantum systems. As demonstration, we\nvalidate the path generator on the harmonic and anharmonic oscillators. The\nlatter is a double-well system without analytic solutions. To preserve the\nperiodic condition for the system, the Fourier transformation is introduced\ninto the flow model to approach a Matsubara representation. With this novel\ndevelopment, the ground-state wave function and low-lying energy levels are\nestimated accurately. Our method offers a new avenue to investigate quantum\nsystems with machine learning assisted Feynman Path integral solving.",
        "positive": "Repairing Stevenson's step in the 4d Ising model: In a recent paper Stevenson claimed that analysis of the data on the wave\nfunction renormalization constant near the critical point of the 4d Ising model\nis not consistent with analytical expectations. Here we present data with\nimproved statistics and show that the results are indeed consistent with\nconventional wisdom once one takes into account the uncertainty of lattice\nartifacts in the analytical computations."
    },
    {
        "anchor": "Scattering phases in the broken phase of the 4-d O(4) non-linear\n  sigma-model: Using Luescher's method we determine the elastic scattering phases in the\nbroken phase of the 4-dimensional O(4) non-linear sigma-model from the\ntwo-particle energy spectrum in a Monte-Carlo study on finite lattices. In the\nisospin-0-channel we observe the sigma-resonance and extract its mass and its\nwidth. In all scattering channels investigated the results are consistent with\nperturbative calculations.",
        "positive": "Topology of trace deformed Yang-Mills theory: In this paper we study, by means of numerical simulations, the topological\nproperties of $SU(3)$ and $SU(4)$ trace deformed Yang-Mills theory defined on $\n\\mathbb{R}^3\\times S^1$, in which center symmetry is recovered even at small\ncompactification radii. In particular, we compute the topological\nsuscpetibility $\\chi$ and the coefficient $b_2$ (related to the fourth cumulant\nof the topological charge distribution). We find that these observables\ncomputed in the deformed theory when center symmetry is recovered are\ncompatible with their values at zero temperature both for 3 and 4 colours"
    },
    {
        "anchor": "Excitations of elementary fermions in gauge Higgs theories: Static quark-antiquark states in QCD, at finite quark separation, have a\nspectrum of metastable states corresponding to string-like excitations of the\ngauge field. In this article I suggest that there may also exist an excitation\nspectrum of heavy fermions in some gauge Higgs theories deep in the Higgs\nphase. In this situation there are no color electric flux tubes connecting\nquarks with antiquarks. There may, nonetheless, exist stable excitations of the\nbosonic fields surrounding an isolated fermion, below the particle production\nthreshold. I present numerical evidence indicating the existence of such\nexcitations in an SU(3) gauge Higgs theory, with the scalar field in the\nfundamental representation of the gauge group.",
        "positive": "Study of quarkonium in QGP from unquenched lattice QCD: This paper discusses the charmonium and bottomonium correlators in the\npseudoscalar channel and the corresponding spectral reconstruction on the\nlattice. The absence of a transport peak in the pseudoscalar channel spectral\nfunction allows for an easier study of the in-medium modification of bound\nstates. However, extracting spectral information from Euclidean correlators is\nstill a numerically ill-posed problem. To constrain the spectral\nreconstruction, we use an ansatz motivated from perturbation theory. The\nperturbative model spectral function has two main contributions: a thermal part\naround the threshold obtained from pNRQCD and the vacuum part well above the\nthreshold. These two regions are matched continuously, and the model spectral\nfunction is obtained by introducing parameters that control the overall thermal\nshift of the peak and the overall amplitude. The lattice correlator data is\ncomputed using clover-improved Wilson valence fermions on large and fine gauge\nfield configurations generated using $N_f=2+1$ flavors Highly Improved\nStaggered Quark (HISQ) action with physical strange quark mass $m_s$, and\nslightly heavy degenerate up and down quark masses $m_l=m_s/5$ that corresponds\nto $m_\\pi\\simeq 320$ MeV. Our results obtained at $T=220$ MeV and $T=251$ MeV\nsuggest that no resonance peaks are needed to describe the charmonium lattice\ndata at these temperatures, while for bottomonium thermally broadened resonance\npeaks persist."
    },
    {
        "anchor": "Lattice QCD at High Temperature and the QGP: We review recent progress in studies of bulk thermodynamics of strongly\ninteracting matter, present results on the QCD equation of state and discuss\nthe status of studies of the phase diagram at non-vanishing quark chemical\npotential.",
        "positive": "Light Hadron Spectrum and Quark Masses from Quenched Lattice QCD: We present details of simulations for the light hadron spectrum in quenched\nQCD carried out on the CP-PACS parallel computer. Simulations are made with the\nWilson quark action and the plaquette gauge action on 32^3x56 - 64^3x112\nlattices at four lattice spacings (a \\approx 0.1-0.05 fm) and the spatial\nextent of 3 fm. Hadronic observables are calculated at five quark masses\n(m_{PS}/m_V \\approx 0.75 - 0.4), assuming the u and d quarks being degenerate\nbut treating the s quark separately. We find that the presence of quenched\nchiral singularities is supported from an analysis of the pseudoscalar meson\ndata. We take m_\\pi, m_\\rho and m_K (or m_\\phi) as input. After chiral and\ncontinuum extrapolations, the agreement of the calculated mass spectrum with\nexperiment is at a 10% level. In comparison with the statistical accuracy of\n1-3% and systematic errors of at most 1.7% we have achieved, this demonstrates\na failure of the quenched approximation for the hadron spectrum: the meson\nhyperfine splitting is too small, and the octet masses and the decuplet mass\nsplittings are both smaller than experiment. Light quark masses are calculated\nusing two definitions: the conventional one and the one based on the\naxial-vector Ward identity. The two results converge toward the continuum\nlimit, yielding m_{ud}=4.29(14)^{+0.51}_{-0.79} MeV. The s quark mass depends\non the strange hadron mass chosen for input: m_s = 113.8(2.3)^{+5.8}_{-2.9} MeV\nfrom m_K and m_s = 142.3(5.8)^{+22.0}_{-0} MeV from m_\\phi, indicating again a\nfailure of the quenched approximation. We obtain \\Lambda_{\\bar{MS}}^{(0)}=\n219.5(5.4) MeV. An O(10%) deviation from experiment is observed in the\npseudoscalar meson decay constants."
    },
    {
        "anchor": "Lattice Simulations with Chemical Potential: After giving an overview of recently invented methods for simulating lattice\nQCD at small mu/T, we discuss some results for bulk thermodynamic quantities of\nQCD matter coming from those methods. We focus on the transition line and the\ncritical endpoint in the QCD phase diagram.",
        "positive": "Meson-Meson Scattering in Lattice QED_2+1: Scattering phase shifts of a meson-meson system in staggered 3-dimensional\nlattice QED are computed. The main task of the simulation is to obtain a\ndiscrete set of two-body energy levels. These are extracted from a 4-point time\ncorrelation matrix and then used to obtain scattering phase shifts. The results\nfor the l=0 and l=2 partial waves are consistent with short- range repulsion\nand intermediate-range attraction of the residual meson- meson interaction."
    },
    {
        "anchor": "On complex Langevin dynamics and zeroes of the measure II: Fermionic\n  determinant: Lattice QCD at non-vanishing chemical potential is studied using the complex\nLangevin equation (CLE). One of the conditions for the correctness of the\nresults of the CLE is that the zeroes of the measure coming from the fermionic\ndeterminant are outside of the distribution of the configurations, or at least\nin a region where support for the distribution is very much suppressed. We\ninvestigate this issue for Heavy Dense QCD (HDQCD) and full QCD at high\ntemperatures. In HDQCD it is found that the configurations move closest to the\nzeroes of the measure around the critical chemical potential of the onset\ntransition, where the sign problem is diminished, but results remain largely\nunaffected. In full QCD at high temperatures the investigation of the spectrum\nof the Dirac operator yields a similar observation: the results are unaffected\nby the issue of the poles.",
        "positive": "Deconfining phase transition on a double-layered torus: Deconfined regions in relativistic heavy ion collisions are limited to small\nvolumes surrounded by a confined exterior. Here the geometry of a double\nlayered torus is discussed, which allows for different temperatures in its two\nlayers. This geometry enables one to approach the QCD continuum limit for small\ndeconfined volumes with confined exteriors in a more realistic fashion than by\nusing periodic boundary conditions. Preliminary data from a study for pure\nSU(3) lattice gauge theory support a substantial increase in a pseudo\ntransition temperature."
    },
    {
        "anchor": "Disorder Parameter of Confinement: The disorder parameter of confinement-deconfinement phase transition based on\nthe monopole action determined previously in $SU(2)$ QCD are investigated. We\nconstruct an operator which corresponds to the order parameter defined in the\nabelian Higgs model. The operator shows proper behaviors as the disorder\nparameter in the numerical simulations of finite temperature QCD.",
        "positive": "Renormalization and lattice artifacts: Lectures given at the Summer School on \"Modern perspectives in lattice QCD\",\nLes Houches, August 3-28, 2009"
    },
    {
        "anchor": "A comparison of analysis techniques for extracting resonance parameters\n  from lattice Monte Carlo data: Different methods for extracting resonance parameters from Euclidean lattice\nfield theory are tested. Monte Carlo simulations of the O(4) non-linear sigma\nmodel are used to generate energy spectra in a range of different volumes both\nbelow and above the inelastic threshold. The applicability of the analysis\nmethods in the elastic region is compared. Problems which arise in the\ninelastic region are also emphasised.",
        "positive": "Lattice Heavy Quark Effective Theory and the Isgur-Wise function: We compute the Isgur-Wise function using heavy quark effective theory\nformulated on the lattice. The non-relativistic kinetic energy term of the\nheavy quark is included to the action as well as terms remaining in the\ninfinite quark mass limit. The classical velocity of the heavy quark is\nrenormalized on the lattice and we determine the renormalized velocity\nnon-perturbatively using the energy-momentum dispersion relation. The slope\nparameter of the Isgur-Wise function at zero recoil is obtained at $\\beta=6.0$\non a $24^3\\times 48$ lattice for three values of $m_{Q}$."
    },
    {
        "anchor": "SU(4) lattice gauge theory with decuplet fermions: Schr\u00f6dinger\n  functional analysis: We complete a program of study of SU(N) gauge theories coupled to two flavors\nof fermions in the two-index symmetric representation by performing numerical\nsimulations in SU(4). The beta function, defined and calculated via the\nSchr\\\"odinger functional, runs more slowly than the two-loop perturbative\nresult. The mass anomalous dimension levels off in strong coupling at a value\nof about 0.45, rendering this theory unsuitable for walking technicolor. A\nlarge-N comparison of this data with results from SU(2) and SU(3) reveals\nstriking regularities.",
        "positive": "Properties of Renormalization Group Transformations: We describe some properties of Renormalization Group transformations.\nEspecially we show why some of the RG transformations have redundant\neigenoperators with eigenvalues that cannot be determined by simple dimensional\nanalysis and give the corresponding formulae."
    },
    {
        "anchor": "Tuning the strange quark mass in lattice simulations: QCD lattice simulations with 2+1 flavours typically start at rather large\nup-down and strange quark masses and extrapolate first the strange quark mass\nto its physical value and then the up-down quark mass. An alternative method of\ntuning the quark masses is discussed here in which the singlet quark mass is\nkept fixed, which ensures that the kaon always has mass less than the physical\nkaon mass. It can also take into account the different renormalisations (for\nsinglet and non-singlet quark masses) occurring for non-chirally invariant\nlattice fermions and so allows a smooth extrapolation to the physical quark\nmasses. This procedure enables a wide range of quark masses to be probed,\nincluding the case with a heavy up-down quark mass and light strange quark\nmass. Results show the correct order for the baryon octet and decuplet spectrum\nand an extrapolation to the physical pion mass gives mass values to within a\nfew percent of their experimental values.",
        "positive": "Low-lying fermion modes of Nf=2 improved Wilson fermions: We present preliminary results for the topological charge and susceptibility\ndetermined from the low-lying eigenmodes of the Wilson-Dirac operator. These\nmodes have been computed on dynamical configurations with Nf=2\nnon-perturbatively improved Wilson fermions. We compare our results with the\neigenmodes of fermions in the quenched approximation."
    },
    {
        "anchor": "Lattice study of K pi scattering in I = 3/2 and 1/2: We report the first lattice QCD results of the scattering amplitudes of the\n$K\\pi$ system for $I = 1/2$ channel together with $I=3/2$ case. We investigate\nall quark diagrams contributing to these iso-spin states, and find that the\nscattering amplitudes are expressed as combinations of only three diagrams\nafter setting the masses of $u$-quark and $d$-quark to be the same.\n  The lattice simulations are performed in the quenched approximation at $\\beta\n= 2.23$ on a 12$^3 \\times 24$ lattice with an improved Iwasaki gauge action. We\nemploy a new dilution-type noise method to get accuracy of data with reasonable\nCPU time. A simple method is proposed and applied to eliminate lattice artefact\ndue to the finite extent of lattice along the time direction.\n  A clear difference in the quark mass dependence between $I=3/2$ and $I=1/2$\nchannels is observed. Although the chiral extrapolation is subtle, we assume\n$E_{K\\pi}^2 \\propto m_{u,d}^2 $, and obtain the $S$-wave scattering lengths as\n$a_0(I=3/2) m_{\\pi} =-0.084^{+0.051}_{-0.064}$ and $a_0(I=1/2) m_{\\pi} = -0.625\n\\pm0.012$. We show all necessary formulas which make the calculation possible.\n  We argue that $\\Lambda N$ is the most appropriate target of the L\\\"uscher's\nformula for baryonic system because it has no $\\pi$ exchange diagrams and has a\nscattering length suitable for a lattice QCD simulation.",
        "positive": "Solution to the gauge-Higgs analyticity paradox: The Fradkin-Shenker theorem proves analyticity in a region that connects\nHiggs to confinement regimes, precluding a phase transition. This conflicts\nwith a simpler analyticity argument applicable to any symmetry-breaking phase\ntransition that requires the phase diagram to be bifurcated. A flaw in the\nFradkin-Shenker and related Osterwalder-Seiler proofs is found which removes\nthis paradox. Higgs and Confinement regions are everywhere separated by a phase\nboundary. A new order parameter allowing this transition to be traced with\nMonte-Carlo simulations without gauge fixing is introduced."
    },
    {
        "anchor": "Minimizing storage in implementations of the overlap lattice-Dirac\n  operator: The overlap lattice-Dirac operator contains the sign function $\\epsilon (H)$.\nRecent practical implementations replace $\\epsilon (H)$ by a ratio of\npolynomials, $H P_n (H^2)/Q_n (H^2)$, and require storage of $2n+2$ large\nvectors. Here I show that one can use only 4 large vectors at the cost of\nexecuting the core conjugate algorithm twice. The slow-down might be less than\nby a factor of 2, depending on the architecture of the computer one uses.",
        "positive": "The non-Abelian dual Meissner effect as color-alignment in SU(2) lattice\n  gauge theory: A new gauge (m-gauge) condition is proposed by means of a generalization of\nthe Maximal Abelian gauge (MAG). The new gauge admits a space time dependent\nembedding of the residual U(1) into the SU(2) gauge group. This embedding is\ncharacterized by a color vector $\\vec{m}(x)$. It turns out that this vector\nonly depends of gauge invariant parts of the link configurations. Our numerical\nresults show color ferromagnetic correlations of the $\\vec{m}(x)$ field in\nspace-time. The correlation length scales towards the continuum limit. For\ncomparison with the MAG, we introduce a class of gauges which smoothly\ninterpolates between the MAG and the m-gauge. For a wide range of the gauge\nparameter, the vacuum decomposes into regions of aligned vectors $\\vec{m}$. The\n''neutral particle problem'' of MAG is addressed in the context of the new\ngauge class."
    },
    {
        "anchor": "Open Boundary Condition, Wilson Flow and the Scalar Glueball Mass: A major problem with periodic boundary condition on the gauge fields used in\ncurrent lattice gauge theory simulations is the trapping of topological charge\nin a particular sector as the continuum limit is approached. To overcome this\nproblem open boundary condition in the temporal direction has been proposed\nrecently. One may ask whether open boundary condition can reproduce the\nobservables calculated with periodic boundary condition. In this work we find\nthat the extracted lowest glueball mass using open and periodic boundary\nconditions at the same lattice volume and lattice spacing agree for the range\nof lattice scales explored in the range 3 GeV $\\leq $ 1/a $\\leq$ 5 GeV. The\nproblem of trapping is overcome to a large extent with open boundary and we are\nable to extract the glueball mass at even larger lattice scale $\\approx$ 5.7\nGeV. To smoothen the gauge fields and to reduce the cut off artifacts recently\nproposed Wilson flow is used. The extracted glueball mass shows remarkable\ninsensitivity to the lattice spacings in the range explored in this work, 3 GeV\n$\\leq$ 1/a $\\leq$ 5.7 GeV.",
        "positive": "Ordering of Spin-$\\frac{1}{2}$ Excitations of the Nucleon in Lattice QCD: We present results for the negative parity low-lying state of the nucleon,\n$N{\\frac{1}{2}}^{-}$ (1535 MeV) ${\\rm S}_{11}$, from a variational analysis\nmethod. The analysis is performed in quenched QCD with the FLIC fermion action.\nThe principal focus of this paper is to explore the level ordering between the\nRoper (${\\rm{P}}_{11}$) and the negative parity ground (${\\rm{S}}_{11}$) states\nof the nucleon. Evidence of the physical level ordering is observed at light\nquark masses. A wide variety of smeared-smeared correlation functions are used\nto construct correlation matrices. A comprehensive correlation matrix analysis\nis performed to ensure an accurate isolation of the $N{\\frac{1}{2}}^{-}$ state."
    },
    {
        "anchor": "QED on a momentum lattice: We investigate the possibility of doing momentum space lattice simulations as\nan alternative to the conventional method. The procedure is introduced and\ntested for quenched QED2 and quenched QED3. Interesting physical applications\nto unquenched QED3 and quenched QED4 are also briefly discussed.",
        "positive": "Hadronic Coupling Constants in Lattice QCD: We calculate the hadronic coupling constants $g_{NN\\pi}$ and $g_{\\rho\\pi\\pi}$\nin QCD, including dynamical quarks in the framework of staggered fermions in\nthe lattice approach. For the nucleon--pion coupling we obtain $g_{NN\\pi} =\n13.8 \\pm 5.8$, to be compared with the experimental value $13.13 \\pm 0.07$. The\n$\\rho\\pi\\pi$ coupling has been analysed for two different sets of operators\nwith the averaged result $g_{\\rho\\pi\\pi} = 4.2 \\pm 1.9$ which is to be compared\nwith the experimental value $6.06 \\pm 0.01$."
    },
    {
        "anchor": "Current status of $\\varepsilon_K$ calculated with lattice QCD inputs: We present results for $\\varepsilon_K$, the indirect CP violation parameter,\ncalculated in the Standard Model using inputs from lattice QCD: the kaon bag\nparameter $\\hat{B}_K$, and the CKM matrix element $V_{cb}$ from the axial\ncurrent form factor for the exclusive decay $\\bar{B}\\to D^*\\ell\\bar{\\nu}$ at\nzero-recoil. In addition, we take the coordinates of the unitarity triangle\napex $(\\bar{\\rho},\\bar{\\eta})$ from the angle-only fit of the UTfit\nCollaboration and use $V_{us}$ to fix $\\lambda$. In order to estimate the\nsystematic error, we also use Wolfenstein parameters from the CKMfitter and\nUTfit. We find a $3.3(2)\\sigma$ difference between $\\varepsilon_K$ and\nexperiment with exclusive $V_{cb}$. We report details of this preliminary\nresult.",
        "positive": "$\u03c1$ meson decay from the lattice: We present preliminary results on the $\\rho$ meson decay width estimated from\nthe scattering phase shift of the I=1 two-pion system. The phase shift is\ncalculated by the finite size formula for non-zero total momentum frame (the\nmoving frame) derived by Rummukainen and Gottlieb, using the $N_f=2$ improved\nWilson fermion action at $m_\\pi/m_\\rho=0.41$ and $L=2.53 {\\rm fm}$."
    },
    {
        "anchor": "Electromagnetic effects on the light hadron spectrum: For some time, the MILC Collaboration has been studying electromagnetic\neffects on light mesons. These calculations use fully dynamical QCD, but only\nquenched photons, which suffices to NLO in XPT. That is, the sea quarks are\nelectrically neutral, while the valence quarks carry charge. For the photons we\nuse the non-compact formalism. We have new results with lattice spacing as\nsmall as 0.045 fm and a large range of volumes. We consider how well chiral\nperturbation theory describes these results and the implications for light\nquark masses",
        "positive": "The Gluon Propagator in Lattice Landau Gauge with twisted boundary\n  conditions: We investigate the infrared behaviour of the gluon propagator in Landau gauge\non a lattice with twisted boundary conditions. Analytic calculations using\nDyson-Schwinger equations, exact renormalization group and stochastic\nquantization show that the gluon propagator in Landau gauge approaches zero for\nsmall momentum. On the other hand lattice calculations and calculations on a\nfour-torus seem to give rise to a non-zero limit. One possible reason for this\ndifference is the existence of zero-momentum fluctuation modes which\npotentially give a massive contribution to the gluon propagator. Our\nsimulations show that with twisted boundary conditions these zero-momentum\nmodes are suppressed and the gluon propagator becomes smaller than in a\nperiodic ensemble."
    },
    {
        "anchor": "Numerical Simulations in Particle Physics: Numerical simulations have become an important tool to understand and predict\nnon-perturbative phenomena in particle physics. In this article we attempt to\npresent a general overview over the field. First, the basic concepts of lattice\ngauge theories are described, including a discussion of currently used\nalgorithms and the reconstruction of continuum physics from lattice results. We\nthen proceed to present some results for QCD, both at low energies and at high\ntemperatures, as well as for the electro-weak sector of the standard model.",
        "positive": "Gluon Versus Meson Exchange in Hadron-Hadron Systems on the Lattice: The interaction of spatially extended heavy hadrons is investigated in the\nframework of lattice QCD with dynamical quarks. In addition to the\nbaryon-baryon potential results for the baryon-antibaryon and for the\nmeson-meson system are presented. It is shown that the expected dipole forces\nhave a very short range and that sea quarks play a minor important role."
    },
    {
        "anchor": "Gauss law at a vertex in Lattice QCD and its gauge invariant Hilbert\n  space: We solve the local Gauss law in lattice QCD in the presence of matter\ncharges. This corresponds to constructing singlet states using Schwinger Bosons\nand Fermions of SU(3) group at each vertex of the lattice. We also calculate\nthe action of various invariant operators on these states required for studying\nthe dynamics.",
        "positive": "An analysis of the nucleon spectrum from lattice partially-quenched QCD: The chiral extrapolation of the nucleon mass, M_n, is investigated using data\ncoming from 2-flavour partially-quenched lattice simulations. A large sample of\nlattice results from the CP-PACS Collaboration is analysed using the leading\none-loop corrections, with explicit corrections for finite lattice spacing\nartifacts. The extrapolation is studied using finite range regularised chiral\nperturbation theory. The analysis also provides a quantitative estimate of the\nleading finite volume corrections. It is found that the discretisation,\nfinite-volume and partial quenching effects can all be very well described in\nthis framework, producing an extrapolated value of M_n in agreement with\nexperiment. Furthermore, determinations of the low energy constants of the\nnucleon mass's chiral expansion are in agreement with previous methods, but\nwith significantly reduced errors. This procedure is also compared with\nextrapolations based on polynomial forms, where the results are less\nencouraging."
    },
    {
        "anchor": "Nucleon spin and quark content at the physical point: We present results on the spin and quark content of the nucleon using $N_f=2$\ntwisted mass clover-improved fermion simulations with a pion mass close to its\nphysical value. We use recently developed methods to obtain accurate results\nfor both connected and disconnected contributions. We provide results for the\naxial charge, quark and gluon momentum fraction as well as the light, strange\nand charm $\\sigma$-terms.",
        "positive": "Infinite-N limit of the eigenvalue density of Wilson loops in 2D SU(N)\n  YM: Starting from an integral representation for the eigenvalue density at finite\nN, it is shown by a saddle-point analysis that the known result (Durhuus and\nOlesen, 1981) can be recovered."
    },
    {
        "anchor": "The deconfining phase transition for SU(N) theories in 2+1 dimensions: The critical temperatures for the 2+1 dimensional $SU(N_c)$ gauge theories\nare calculated, for $N_c = 4,5,6$. The transition is shown to be first order\nfor $N_c \\geq 5$. The critical temperature and latent heat are extrapolated to\n$N_c = \\infty$.",
        "positive": "Is the ground state of Yang-Mills theory Coulombic?: We study trial states modelling the heavy quark-antiquark ground state in\nSU(2) Yang-Mills theory. A state describing the flux tube between quarks as a\nthin string of glue is found to be a poor description of the continuum ground\nstate; the infinitesimal thickness of the string leads to UV artifacts which\nsuppress the overlap with the ground state. Contrastingly, a state which\nsurrounds the quarks with non-abelian Coulomb fields is found to have a good\noverlap with the ground state for all charge separations. In fact, the overlap\nincreases as the lattice regulator is removed. This opens up the possibility\nthat the Coulomb state is the true ground state in the continuum limit."
    },
    {
        "anchor": "QCD thermodynamics with O(a) improved Wilson fermions at Nf=2: We present an update of our study of the phase diagram of two-flavour QCD at\nzero baryon density with dynamical $O(a)$ improved Wilson quarks. All\nsimulations are done on lattices with a temporal extent of $N_t=16$ and spatial\nextent $L=32,48$ and 64, ensuring that discretisation effects are small and\nfinite size effects can be controlled. In the approach to the chiral limit we\ncurrently have three scans with pion masses between 540 and 200 MeV. In this\nproceedings article the focus is on the new scan at $m_\\pi=200$ MeV and the\nmeasurement of screening masses. We also present first results concerning a\ntest of scaling in the approach to the chiral limit and the chiral\nextrapolation of the difference of screening masses in scalar and pseudoscalar\nchannels, which provides a measure for the strength of the anomalous breaking\nof the $U_A(1)$ symmetry.",
        "positive": "Evolutionary Fitting Methods for the Extraction of Mass Spectra in\n  Lattice Field Theory: We present an application of evolutionary algorithms to the curve-fitting\nproblems commonly encountered when trying to extract particle masses from\ncorrelators in Lattice QCD. Harnessing the flexibility of evolutionary methods\nin global optimization allows us to dynamically adapt the number of states to\nbe fitted along with their energies so as to minimize overall \\chi^2/(d.o.f.),\nleading to a promising new way of extracting the mass spectrum from measured\ncorrelation functions."
    },
    {
        "anchor": "The isotensor axial polarisability and lattice QCD input for nuclear\n  double-$\u03b2$ decay phenomenology: The potential importance of short-distance nuclear effects in double-$\\beta$\ndecay is assessed using a lattice QCD calculation of the $nn\\rightarrow pp$\ntransition and effective field theory methods. At the unphysical quark masses\nused in the numerical computation, these effects, encoded in the isotensor\naxial polarisability, are found to be of similar magnitude to the nuclear\nmodification of the single axial current, which phenomenologically is the\nquenching of the axial charge used in nuclear many-body calculations. This\nfinding suggests that nuclear models for neutrinoful and neutrinoless\ndouble-$\\beta$ decays should incorporate this previously neglected contribution\nif they are to provide reliable guidance for next-generation neutrinoless\ndouble-$\\beta$ decay searches. The prospects of constraining the isotensor\naxial polarisabilities of nuclei using lattice QCD input into nuclear many-body\ncalculations are discussed.",
        "positive": "Chemical potential (in)dependence of hadron scatterings in the hadronic\n  phase of QCD-like theories and its applications: We formulate a method for calculating the hadron-hadron scattering amplitudes\nat nonzero chemical potential ($\\mu$) in the hadronic phase at zero\ntemperature, where the baryon number symmetry remains to be violated. Although\nit is widely believed that the physical quantities do not change even if we\nturn on a small $\\mu$ at zero temperature, the shape of correlation functions\nfor a single hadron depends on $\\mu$. Then, the dispersion relation of the\nsingle hadron is modified to $E({\\bf p},\\mu) = \\sqrt{{\\bf p}^2+m^2}-\\mu n_{O}$.\nHere, $m$ and $n_O$ denote the hadron mass at $\\mu=0$ and the quantum number,\nrespectively. From this relation, it is possible that the effective mass of the\nhadron depends on $\\mu$. We extend the HAL QCD method at $\\mu=0$ to the case of\n$\\mu \\ne 0$, which allows us to extract the scattering phase shifts via the\ninteraction potential. We have found that the interaction potential can depend\non $\\mu$ only through the effective mass while the scattering phase shifts,\nobtained by solving the Schr\\\"{o}dinger equation with the interaction\npotential, are independent of $\\mu$. We also numerically analyze the S-wave\nscatterings of two pions with isospin $I=2$ and two scalar diquarks within the\nframework of QC$_{2}$D at nonzero quark chemical potential. While the lattice\nis not exactly set to zero temperature, the $\\mu$-independence can be observed.\nFurthermore, we improve the results for the S-wave scatterings of two hadrons\nobtained above by taking the $\\mu$-independence for granted. Thanks to the\nasymmetric property of the correlation functions for diquarks at $\\mu\\neq0$, we\ncan access a long-$\\tau$ regime and can reduce the systematic error coming from\ninelastic contributions."
    },
    {
        "anchor": "Unstable Modes in Three-Dimensional SU(2) Gauge Theory: We investigate SU(2) gauge theory in a constant chromomagnetic field in three\ndimensions both in the continuum and on the lattice. Using a variational method\nto stabilize the unstable modes, we evaluate the vacuum energy density in the\none-loop approximation. We compare our theoretical results with the outcomes of\nthe numerical simulations.",
        "positive": "More chiral lattice fermions: Instead of the Ginsparg-Wilson relation only generalized chiral symmetry is\nrequired. The resulting much larger class of Dirac operators for massless\nfermions is investigated and a general construction for them is given. It is\nalso shown that the new class still leads properly to Weyl fermions and to\nchiral gauge theories."
    },
    {
        "anchor": "Super Yang-Mills Theory on Lattice and the Transformation: We present a new lattice super Yang-Mills theory and its SUSY transformation.\nAfter our formulation of the model in a fundamental lattice, it is extended to\nthe whole lattice with a substructure of modulo 2.",
        "positive": "On the colour confinement and the minimal surface: In the analysis of the energy of the four-quark system obtained in the SU(2)\nlattice Monte Carlo, the f-model in which the transition potential is expressed\nin the form $f=f_c exp(-k_A b_s A-k_P\\sqrt{b_s}P)$, where A is the area and P\nis the perimeter of the Wilson loop, was successful in the simple\nconfigurations of the four quarks. In the case of tetrahedral geometry, an\nestimation of the minimal surface whose contours run the positions of the four\nquarks is necessary. We show that the regular surface approximation whose area\ncan be calculated analytically, is a good approximation for evaluating the\nminimal surface. The numerical value of the coefficient $k_A b_s$ is close to\n$2 fm^{-2}$ which is the density of the $Z_2$ vortex in the SU(2) lattice Monte\nCarlo."
    },
    {
        "anchor": "So you want to be a lattice theorist?: For this after dinner talk I intersperse images of real lattices with a\ndiscussion of the motivations for lattice gauge theory and some current\nunresolved issues.",
        "positive": "Prospects for a lattice computation of rare kaon decay amplitudes:\n  $K\\to\u03c0\\ell^+\\ell^-$ decays: The rare kaon decays $K\\to\\pi\\ell^+\\ell^-$ and $K\\to\\pi\\nu\\bar{\\nu}$ are\nflavor changing neutral current (FCNC) processes and hence promising channels\nwith which to probe the limits of the standard model and to look for signs of\nnew physics. In this paper we demonstrate the feasibility of lattice\ncalculations of $K\\to\\pi\\ell^+\\ell^-$ decay amplitudes for which long-distance\ncontributions are very significant. We show that the dominant finite-volume\ncorrections (those decreasing as powers of the volume) are negligibly small and\nthat, in the four-flavor theory, no new ultraviolet divergences appear as the\nelectromagnetic current $J$ and the effective weak Hamiltonian $H_W$ approach\neach other. In addition, we demonstrate that one can remove the unphysical\nterms which grow exponentially with the range of the integration over the time\nseparation between $J$ and $H_W$. We will now proceed to exploratory numerical\nstudies with the aim of motivating further experimental measurements of these\ndecays. Our work extends the earlier study by Isidori, Turchetti and Martinelli\nwhich focussed largely on the renormalization of ultraviolet divergences. In a\ncompanion paper we discuss the evaluation of the long-distance contributions to\n$K\\to\\pi\\nu\\bar{\\nu}$ decays; these contributions are expected to be at the\nlevel of a few percent for $K^+$ decays."
    },
    {
        "anchor": "Computation of parton distributions from the quasi-PDF approach at the\n  physical point: We show the first results for parton distribution functions within the proton\nat the physical pion mass, employing the method of quasi-distributions. In\nparticular, we present the matrix elements for the iso-vector combination of\nthe unpolarized, helicity and transversity quasi-distributions, obtained with\n$N_f=2$ twisted mass clover-improved fermions and a proton boosted with\nmomentum $|\\vec{p}|=0.83\\mbox{ GeV}$. The momentum smearing technique has been\napplied to improve the overlap with the proton boosted state. Moreover, we\npresent the renormalized helicity matrix elements in the RI$'$ scheme,\nfollowing the non-perturbative renormalization prescription recently developed\nby our group.",
        "positive": "On the suitability of the Brillouin action as a kernel to the overlap\n  procedure: We investigate the Brillouin action in terms of its suitability as a kernel\nto the overlap procedure, with a view on both heavy and light quark physics. We\nuse the diagonal elements of the Kenney-Laub family of iterations for the\nsparse matrix sign function, since they grow monotonically and facilitate\ncascaded preconditioning strategies with different rational approximations to\nthe sign function. We find that the overlap action with the Brillouin kernel is\nsignificantly better localized than the version with the Wilson kernel."
    },
    {
        "anchor": "Thermal Phase Transition in Mixed Action SU(3) Lattice Gauge Theory and\n  Wilson Fermion Thermodynamics: We study the thermal phase diagram of pure SU(3) lattice gauge theory with\nfundamental and adjoint couplings. We improve previous estimates of the\nposition of the bulk transition line and determine the thermal deconfinement\ntransition lines for $N_t=2,4,6,$ and 8. The endpoint of the bulk transition\nline $(\\beta_f, \\beta_a)=(4.00(7), 2.06(8))$ improves upon earlier estimates\nobtained using smaller lattice sizes. For $N_t > 4$ the deconfinement\ntransition line splits cleanly away from the bulk transition line. With\nincreasing $N_t$ the thermal deconfinement transition lines shift to\nincreasingly weaker coupling, joining onto the bulk transition line at\nincreasingly larger $\\beta_a$ in a pattern consistent with the usual\nuniversality picture of lattice gauge theories. We also discuss the possible\nconsequences of an induced adjoint term from the fermionic determinant and\ndetermine this induced term numerically with a microcanonical demon method for\ntwo flavors of dynamical Wilson fermions.",
        "positive": "Finite-volume corrections to low-energy constants from the partially\n  quenched effective theory: We calculate finite-volume corrections to the low-energy constants $\\Sigma$\nand $F$ in the epsilon-regime of QCD using partially quenched chiral\nperturbation theory in the supersymmetry formulation without a singlet\nparticle. We comment on how to minimize these corrections in lattice\nsimulations of QCD."
    },
    {
        "anchor": "Toward extracting the scattering phase shift from integrated correlation\n  functions II: a relativistic lattice field theory model: In present work, a relativistic relation that connects the difference of\ninteracting and non-interacting integrated two-particle correlation functions\nin finite volume to infinite volume scattering phase shift through an integral\nis derived. We show that the difference of integrated finite volume correlation\nfunctions converge rapidly to its infinite volume limit as the size of periodic\nbox is increased. The fast convergence of our proposed formalism is illustrated\nby analytic solutions of a contact interaction model, the perturbation theory\ncalculation, and also Monte Carlo simulation of a complex $\\phi^4$ lattice\nfield theory model.",
        "positive": "Low Energy Constants from the zero mode contribution to the\n  pseudo-scalar correlator: We apply different types of overlap operators in quenched QCD simulations to\ncompute the zero mode contribution to the pseudo-scalar correlator. In\nparticular we use the conventional Neuberger Dirac operator and the overlap\nhypercube Dirac operator. Confronting our data with the analytical predictions\nby Chiral Perturbation Theory we evaluate the pion decay constant and the\nparameter \\alpha of the quenched chiral Lagrangian."
    },
    {
        "anchor": "The electrical conductivity and soft photon emissivity of the QCD plasma: The electrical conductivity in the hot phase of the QCD plasma is extracted\nfrom a quenched lattice measurement of the Euclidean time vector correlator for\n1.5 < T/T_c < 3. The spectral density in the vicinity of the origin is examined\nusing a method specially adapted to this region, and a peak at small energies\nis seen. The continuum limit of the electrical conductivity, and the closely\nrelated soft photon emissivity of the QCD plasma, are then extracted from a fit\nto the Fourier transform of the temporal vector correlator.",
        "positive": "Hadronic matrix elements of neutral-meson mixing through lattice QCD: Neutral-meson mixing is loop suppressed in the Standard Model, leading to the\npossibility of enhanced sensitivity to new physics. The uncertainty in Standard\nModel predictions for $B$-meson oscillation frequencies is dominated by\ntheoretical uncertainties within the short-distance $B$-meson hadronic matrix\nelements, motivating the need for improved precision. In $D$-meson mixing, the\nStandard Model short-distance contributions are further suppressed by the GIM\nmechanism allowing for the possibility of large new physics enhancements. A\nfirst-principle determination of the $D$-meson short-distance hadronic matrix\nelements will allow for model-discrimination between the new physics theories.\nI review recently published and ongoing lattice calculations of hadronic matrix\nelements in $B$ and $D$-meson mixing with emphasis on the Fermilab lattice and\nMILC collaboration effort on the determination of the $B$ and $D$-meson mixing\nhadronic matrix elements using the methods of lattice QCD."
    },
    {
        "anchor": "Nucleon electromagnetic form factors with 2+1 flavors of domain wall\n  fermions: We present the recent high-statistics calculations of the nucleon\nelectromagnetic form factors with fully dynamical domain wall fermions on the\n32^3x64 lattices generated by the RBC and UKQCD collaborations, with pion\nmasses at roughly 297 MeV, 355 MeV and 403 MeV. We study the phenomenological\nfits to the momentum transfer dependence of the form factors and investigate\nchiral extrapolations for the Dirac radius, Pauli radius and the anomalous\nmagnetic moment using two variants of chiral effective field theories, the\nsmall scale expansion (SSE) and covariant baryon chiral perturbation theory.",
        "positive": "Chiral symmetry and axial U(1) symmetry in finite temperature QCD with\n  domain-wall fermion: We study the restoration of the spontaneously broken chiral symmetry and the\nanomalously broken axial U(1) symmetry in finite temperature QCD at zero\nchemical potential. We use 2 flavors lattice QCD with optimal domain-wall\nfermion on the $ 16^3 \\times 6 $ lattice, with the extent $ N_s = 16 $ in the\nfifth dimension, in the temperature range $ T = 130-230 $ MeV. To examine the\nrestoration of the chiral symmetry and the axial $ U(1) $ symmetry, we use\ndiluted $ Z_2 $ noises to calculate the chiral condensate, and the chiral\nsusceptibilities in the scalar and pseudoscalar meson channels, for flavor\nsinglet and non-singlet respectively. From the degeneracy of the chiral\nsusceptibilities around $ T_c $, it suggests that the axial $ U(1) $ symmetry\nis restored in the chirally symmetric phase. Moreover, we examine the spectral\ndensity $ \\rho(\\lambda_c) $ of the 4D effective Dirac operator with exact\nchiral symmetry, which is obtained by computing zero modes plus (180+180)\nconjugate pairs of low-lying modes for each gauge configuration. The\nsuppression of low modes in the spectral density provides a consistency check\nof the restoration of axial $ U(1) $ symmetry in the chirally symmetric phase."
    },
    {
        "anchor": "The CLS 2+1 flavor simulations: We report on the status of large volume simulations with 2+1 dynamical\nfermions which are being performed by the CLS initiative. The algorithmic\ndetails include: open boundary conditions, twisted mass reweighting and RHMC,\nwhereas the main feature of the simulation strategy is the approach to the\nphysical point along a trajectory of constant trace of the mass matrix. We\ncomment on the practical side of the above issues using as examples some of the\nnewly generated ensembles, which presently cover lattice spacings between 0.05\nfm and 0.11 fm and pion masses between 150 MeV and 415 MeV.",
        "positive": "On the Non-Abelian Stokes Theorem: We present the non-Abelian Stokes theorem for the Wilson loop in various\nforms and discuss its meaning. Its validity has been recently questioned by\nFaber, Ivanov, Troitskaya and Zach. We demonstrate that all points of their\ncriticism are based on mistakes in mathematics. Finally, we derive a variant of\nour formula for the Wilson loop in lattice regularization."
    },
    {
        "anchor": "Lambda_b -> Lambda l+ l- form factors and differential branching\n  fraction from lattice QCD: We present the first lattice QCD determination of the $\\Lambda_b \\to \\Lambda$\ntransition form factors that govern the rare baryonic decays $\\Lambda_b \\to\n\\Lambda l^+ l^-$ at leading order in heavy-quark effective theory. Our\ncalculations are performed with 2+1 flavors of domain-wall fermions, at two\nlattice spacings and with pion masses down to 227 MeV. Three-point functions\nwith a wide range of source-sink separations are used to extract the\nground-state contributions. The form factors are extrapolated to the physical\nvalues of the light-quark masses and to the continuum limit. We use our results\nto calculate the differential branching fractions for $\\Lambda_b \\to \\Lambda\nl^+ l^-$ with $l=e,\\mu,\\tau$ within the standard model. We find agreement with\na recent CDF measurement of the $\\Lambda_b \\to \\Lambda \\mu^+ \\mu^-$\ndifferential branching fraction.",
        "positive": "QCD Thermodynamics with Domain Wall Fermions: We present our recent studies of the pseudo-critical temperature, $T_c$, of\nQCD using domain wall fermions. Domain wall fermions have the advantage that\nthey preserve exact SU(2) chiral symmetry at finite lattice spacing in the\nlimit that $L_s \\to \\infty$. The RBC Collaboration has performed a set of\ndynamical calculations at $L_s = 32$ and $N_t = 8$ using the Iwasaki gauge\naction with two light quarks ($m_l a = 0.003$) and one strange quark ($m_s a =\n0.037$). A clear signal for the crossover transition can be seen in the light\nchiral susceptibility, as well as in the Wilson line. However, at $L_s = 32$,\nthe residual chiral symmetry breaking is not yet fully under control. We also\npresent preliminary results from the HotQCD Collaboration with $N_t = 8$ and\n$L_s = 96$, where the effects of the residual chiral symmetry breaking are\nreduced compared to $L_s = 32$."
    },
    {
        "anchor": "Perturbative study of the Gluino-Glue operator in SYM: We investigate the renormalization of the Gluino-Glue operator, using both\nLattice Perturbation Theory (LPT) and a Gauge Invariant Renormalization Scheme\n(GIRS). The latter scheme involves gauge-invariant Green's functions of two\noperators at different space-time points, which can be also computed via\nnumerical simulations. There is no need to fix a gauge and the mixing with\ngauge noninvariant operators is inconsequential. We calculate perturbatively\nthe conversion factor relating GIRS with the Modified Minimal Subtraction\nscheme. On the other hand, the Gluino-Glue operator being mixes with several\ngauge noninvariant operators which have the same quantum numbers. The\ndetermination of the mixing matrix on the lattice demands the calculation of\n2-pt and 3-pt Green's functions with external gluon, gluino and ghost fields\nusing LPT. We compute at one-loop order the renormalization of the Gluino-Glue\noperator and all operator mixing coefficients.",
        "positive": "Charm physics with physical light and strange quarks using domain wall\n  fermions: We present a study of charm physics using RBC/UKQCD 2+1 flavour physical\npoint domain wall fermion ensembles for the light quarks as well as for the\nvalence charm quark. After a brief motivation of domain wall fermions as a\nsuitable heavy quark discretisation we will show first results for masses and\nmatrix elements."
    },
    {
        "anchor": "Probing technicolor theories with staggered fermions: One exciting possibility of new physics beyond the Standard Model is that the\nfundamental Higgs sector is replaced by a strongly-interacting gauge theory,\nknown as technicolor. A viable theory must break chiral symmetry dynamically,\nlike in QCD, to generate Goldstone bosons which become the longitudinal\ncomponents of the W and Z. By measuring the eigenvalues of the Dirac operator,\none can determine if chiral symmetry is in fact spontaneously broken. We\nsimulate SU(3) gauge theory with n_s=2 and 3 staggered flavors in the\nfundamental representation, corresponding to N_f=8 and 12 flavors in the\ncontinuum limit. Although our first findings show that both theories are\nconsistent with dynamically broken chiral symmetry and QCD-like behavior,\nflavor breaking effects in the spectrum may require further clarifications\nbefore final conclusions can be drawn. We also compare various improved\nstaggered actions, to suppress this potentially large flavor breaking.",
        "positive": "Surface Tension, Surface Stiffness, and Surface Width of the\n  3-dimensional Ising Model on a Cubic Lattice: We compute properties of the interface of the 3-dimensional Ising model for a\nwide range of temperatures, covering the whole region from the low temperature\ndomain through the roughening transition to the bulk critical point. The\ninterface tension sigma is obtained by integrating the surface energy density\nover the inverse temperature beta. We use lattices of size L x L x T, with L up\nto 64, and T up to 27. The simulations with antiperiodic boundary conditions in\nT-direction are done with the Hasenbusch-Meyer interface cluster algorithm that\nturns out to be very efficient. We demonstrate that in the rough phase the\nlarge distance behavior of the interface is well described by a massless\nGaussian dynamics. The surface stiffness coefficient kappa is determined. We\nalso attempt to determine the correlation length xi and study universal\nquantities like xi^2 * sigma and xi^2 * kappa. Results for the interfacial\nwidth on lattices up to 512 x 512 x 27 are also presented."
    },
    {
        "anchor": "Center vortex model for the infrared sector of SU(4) Yang-Mills theory:\n  String tensions and deconfinement transition: A random vortex world-surface model for the infrared sector of SU(4)\nYang-Mills theory is constructed, focusing on the confinement properties and\nthe behavior at the deconfinement phase transition. Although the corresponding\ndata from lattice Yang-Mills theory can be reproduced, the model requires a\nmore complex action and considerably more tuning than the SU(2) and SU(3) cases\nstudied previously. Its predictive capabilities are accordingly reduced. This\nbehavior has a definite physical origin, which is elucidated in detail in the\npresent work. As the number of colors is raised in Yang-Mills theory, the\ncorresponding infrared effective vortex description cannot indefinitely\ncontinue to rely on dynamics determined purely by vortex world-surface\ncharacteristics; additional color structures present on the vortices begin to\nplay a role. As evidenced by the modeling effort reported here, definite\nsignatures of this behavior appear in the case of four colors.",
        "positive": "Analytic continuation of finite density QCD with heavy quarks in the\n  strong coupling region: Complex nature of finite density QCD with heavy quarks in the strong coupling\nregion is studied. For this purpose, we consider the effective potential as a\nfunction of Polyakov line, and study thermodynamic singularities and associated\nStokes boundaries in the complex chemical potential plane. We also perform an\nexplicit analytic continuation of the first order transition and crossover\nlines in the complex chemical potential plane."
    },
    {
        "anchor": "Chiral interpolation in a finite volume: A simulation of lattice QCD at (or even below) the physical pion mass is\nfeasible on a small lattice size of \\sim 2 fm. The results are, however,\nsubject to large finite volume effects. In order to precisely understand the\nchiral behavior in a finite volume, we develop a new computational scheme to\ninterpolate the conventional epsilon and p regimes within chiral perturbation\ntheory. In this new scheme, we calculate the two-point function in the\npseudoscalar channel, which is described by a set of Bessel functions in an\ninfra-red finite way as in the epsilon regime, while chiral logarithmic effects\nare kept manifest as in the p regime. The new ChPT formula is compared to our\n2+1- flavor lattice QCD data near the physical up and down quark mass, mud \\sim\n3 MeV on an L \\sim 1.8 fm lattice. We extract the pion mass = 99(4) MeV, from\nwhich we attempt a chiral \"interpolation\" of the observables to the physical\npoint.",
        "positive": "Two-Nucleon Higher Partial-Wave Scattering from Lattice QCD: We present a determination of nucleon-nucleon scattering phase shifts for l\n>= 0. The S, P, D and F phase shifts for both the spin-triplet and spin-singlet\nchannels are computed with lattice Quantum ChromoDynamics. For l > 0, this is\nthe first lattice QCD calculation using the Luscher finite-volume formalism.\nThis required the design and implementation of novel lattice methods involving\ndisplaced sources and momentum-space cubic sinks. To demonstrate the utility of\nour approach, the calculations were performed in the SU(3)-flavor limit where\nthe light quark masses have been tuned to the physical strange quark mass,\ncorresponding to m_pi = m_K ~ 800 MeV. In this work, we have assumed that only\nthe lowest partial waves contribute to each channel, ignoring the unphysical\npartial wave mixing that arises within the finite-volume formalism. This\nassumption is only valid for sufficiently low energies; we present evidence\nthat it holds for our study using two different channels. Two spatial volumes\nof V ~ (3.5 fm)^3 and V ~ (4.6 fm)^3 were used. The finite-volume spectrum is\nextracted from the exponential falloff of the correlation functions. Said\nspectrum is mapped onto the infinite volume phase shifts using the\ngeneralization of the Luscher formalism for two-nucleon systems."
    },
    {
        "anchor": "Lattice QCD determination of neutron-antineutron matrix elements with\n  physical quark masses: Matrix elements of six-quark operators are needed to extract new physics\nconstraints from experimental searches for neutron-antineutron oscillations.\nThis work presents in detail the first lattice quantum chromodynamics\ncalculations of the necessary neutron-antineutron transition matrix elements\nincluding calculation methods and discussions of systematic uncertainties.\nImplications of isospin and chiral symmetry on the matrix elements, power\ncounting in the isospin limit, and renormalization of a chiral basis of\nsix-quark operators are discussed. Calculations are performed with a\nchiral-symmetric discretization of the quark action and physical light quark\nmasses in order to avoid the need for chiral extrapolation. Non-perturbative\nrenormalization is performed, including a study of lattice cutoff effects.\nExcited-state effects are studied using two nucleon operators and multiple\nvalues of source-sink separation. Results for the dominant matrix elements are\nfound to be significantly larger compared to previous results from the MIT bag\nmodel. Future calculations are needed to fully account for systematic\nuncertainties associated with discretization and finite-volume effects but are\nnot expected to significantly affect this conclusion.",
        "positive": "Leading-order hadronic contributions to a_\u03bc and \u03b1_{QED} from\n  N_f=2+1+1 twisted mass fermions: We present the first four-flavour lattice calculation of the leading-order\nhadronic vacuum-polarisation contribution to the anomalous magnetic moment of\nthe muon, a_{\\mu}^{hvp}, and the hadronic running of the QED coupling constant,\n\\Delta \\alpha_{QED}^{hvp} (Q^2). In the heavy sector a mixed-action setup is\nemployed. The bare quark masses are determined from matching the K- and D-meson\nmasses to their physical values. Several light quark masses are used in order\nto yield a controlled extrapolation to the physical pion mass by utilising a\nrecently proposed improved method. We demonstrate that this method also works\nin the four-flavour case."
    },
    {
        "anchor": "Flux tubes in QCD with (2+1) HISQ fermions: We investigate the transverse profile of the chromoelectric field generated\nby a quark-antiquark pair in the vacuum of (2+1) flavor QCD. Monte Carlo\nsimulations are performed adopting the HISQ/tree action discretization, as\nimplemented in the publicly available MILC code, suitably modified to measure\nthe chromoelectric field. We work on the line of constant physics, with\nphysical strange quark mass $m_s$ and light to strange mass ratio $m_l/m_s =\n1/20$.",
        "positive": "The Hubbard model in the canonical formulation: We describe non-relativistic fermions on the lattice (Hubbard model) in the\ncanonical formulation using transfer matrices in fixed fermion number sectors\nsuch that the partition function becomes fully factorized in time. By\nanalytically integrating out the auxiliary Hubbard-Stratanovich field due to\nthe four-fermion interaction, we express the system in terms of discrete, local\nfermion occupation numbers which are the only remaining degrees of freedom. We\nshow the close relation to the fermion loop and the fermion bag formulation.\nOne can prove that in 1+1 dimension the fermion sign problem is absent.\nFinally, we construct improved estimators for the ground state energy, 2-point\nfunctions, and for the chemical potential."
    },
    {
        "anchor": "Propagation of particles on a torus: In this study, based on the variational principle and Faddeev method, we\npresent a general framework for finding the propagating solutions of multiple\ninteracting particles on a torus. Two different versions of multiparticle\nsecular equations are presented. Version one shows how the propagating\nsolutions on a torus and the infinite volume dynamics are connected. The second\nversion may be more suitable and robust for the task of lattice quantum\nchromodynamics data analysis. The proposed formalism may also be useful for\nstudying the effects of few-body interactions on the electronic band structure\nin condensed matter physics.",
        "positive": "Effective thermal potential between static $Q$ and $\\bar Q$ in SU(3)\n  gauge theory: A non-perturbative calculation of the effective thermal potential between\nheavy $Q$ and $\\bar Q$ from lattice QCD is difficult, and usually involves a\nBayesian analysis. Here we present a simple method to obtain the potential from\nsmeared Wilson loop, using the structure of the thermal Wilson loop. We present\nresults for the $Q \\bar Q$ thermal potential in a gluonic plasma for\ntemperatures $\\lesssim 2 T_c$. We also present preliminary results for the\neffective potential when the $Q$ and $\\bar Q$ are in octet color configuration."
    },
    {
        "anchor": "Irregular parameter dependence of numerical results in tensor\n  renormalization group analysis: We study the parameter dependence of numerical results obtained by the tensor\nrenormalization group. We often observe an irregular behavior as the parameters\nare varied with the method, which makes it difficult to perform the numerical\nderivatives in terms of the parameter. With the use of two-dimensional Ising\nmodel we explicitly show that the sharp cutoff used in the truncated singular\nvalue decomposition causes this unwanted behavior when the level crossing\nhappens between singular values below and above the truncation order as the\nparameters are varied. We also test a smooth cutoff, instead of the sharp one,\nas a truncation scheme and discuss its effects.",
        "positive": "Lattice Gauge Theories and the Heisenberg Antiferromagnetic Chain: We study the strongly coupled 2-flavor lattice Schwinger model and the\nSU(2)-color QCD_2. The strong coupling limit, even with its inherent\nnonuniversality, makes accurate predictions of the spectrum of the continuum\nmodels and provides an intuitive picture of the gauge theory vacuum. The\nmassive excitations of the gauge model are computable in terms of spin-spin\ncorrelators of the quantum Heisenberg antiferromagnetic spin-1/2 chain."
    },
    {
        "anchor": "Theories with global gauge anomalies on the lattice: A global anomaly in a chiral gauge theory manifests itself in different ways\nin the continuum and on the lattice. In the continuum case, functional\nintegration of the fermion determinant over the whole space of gauge fields\nyields zero. In the case of the lattice, it is not even possible to define a\nfermion measure over the whole space of gauge configurations. However, this is\nnot necessary, and as in the continuum, a reduced functional integral is\nsufficient for the existence of the theory.",
        "positive": "Standard Model Heavy Flavor physics on the Lattice: Lattice QCD calculations in charm and bottom physics are particularly\nimportant because they can provide the hadronic weak decay matrix elements\nneeded for key constraints on the CKM Unitarity Triangle. I will summarise\nrecent results in this area, paying particular attention to sources of error,\ncomparison between methods and tests of results against experiment, for\nexample, in the spectrum. Updated world averages for decay constants this year\nare : $f_{D_s}$=248.6(2.4) MeV; $f_D$ = 212.1(3.4) MeV; $f_{B_s}$ = 227(4) MeV;\n$f_B$ = 190(4) MeV. Note that B decay constants are clearly lower than the\ncorresponding D decay constants. Improved $D$ semileptonic form factors, both\nshape and normalisation, now allow the direct determination of $V_{cs}$ and\n$V_{cd}$ to 3% and 5% respectively. This year we also have a clear\ndemonstration that dependence of form factors on the spectator quark mass\nbetween light and strange is very small. Apart from the phenomenology\nimplications, this has practical application to the normalisation of branching\nfractions in experiment. The current best Standard model rate for a key LHC\nmode sensitive to new physics - $B_{(s)} \\rightarrow \\mu^+\\mu^-$ - is derived\nfrom lattice QCD calculations on $B/B_s$ mixing rates. I will discuss the\ncurrent result and prospects for improving lattice QCD errors."
    },
    {
        "anchor": "Domain decomposition and multilevel integration for fermions: The numerical computation of many hadronic correlation functions is\nexceedingly difficult due to the exponentially decreasing signal-to-noise ratio\nwith the distance between source and sink. Multilevel integration methods,\nusing independent updates of separate regions in space-time, are known to be\nable to solve such problems but have so far been available only for pure gauge\ntheory. We present first steps into the direction of making such integration\nschemes amenable to theories with fermions, by factorizing a given observable\nvia an approximated domain decomposition of the quark propagator. This allows\nfor multilevel integration of the (large) factorized contribution to the\nobservable, while its (small) correction can be computed in the standard way.",
        "positive": "Protecting local and global symmetries in simulating 1+1-D non-abelian\n  gauge theories: Efficient quantum simulation protocols for any quantum theories demand\nefficient protection protocols for its underlying symmetries. This task is\nnontrivial for gauge theories as it is involves local symmetry/invariance. For\nnon-Abelian gauge theories, protecting all the symmetries generated by a set of\nmutually non-commuting generators, is particularly difficult. In this letter, a\nglobal symmetry-protection protocol is proposed. Using the novel\nloop-string-hadron formalism of non-Abelian lattice gauge theory, we\nnumerically demonstrate that all of the local symmetries get protected even for\nlarge time by this global symmetry protection scheme. With suitable protection\nstrength, the dynamics of a (1+1)-dimensional SU(2) lattice gauge theory\nremains confined in the physical Hilbert space of the theory even in presence\nof explicit local symmetry violating terms in the Hamiltonian that may occur in\nboth analog and digital simulation schemes as an error. The whole scheme holds\nfor SU(3) gauge theory as well."
    },
    {
        "anchor": "A solution to the fermion doubling problem for supersymmetric theories\n  on the transverse lattice: Species doubling is a problem that infects most numerical methods that use a\nspatial lattice. An understanding of species doubling can be found in the\nNielsen-Ninomiya theorem which gives a set of conditions that require species\ndoubling. The transverse lattice approach to solving field theories, which has\nat least one spatial lattice, fails one of the conditions of the\nNielsen-Ninomiya theorem nevertheless one still finds species doubling for the\nstandard Lagrangian formulation of the transverse lattice. We will show that\nthe Supersymmetric Discrete Light Cone Quantization (SDLCQ) formulation of the\ntransverse lattice does not have species doubling.",
        "positive": "Numerical analysis of the spectrum of the Dirac operator in\n  four-dimensional SU(2) gauge fields: Two numerical algorithms for the computation of eigenvalues of Dirac\noperators in lattice gauge theories are described: one is an accelerated\nconjugate gradient method, the other one a standard Lanczos method. Results\nobtained by Cullum's and Willoughby's variant of the Lanczos method (whose\nconvergence behaviour is closely linked with the local spectral density) are\npresented for euclidean Wilson fermions in quenched and unquenched SU(2) gauge\nfields. Complete spectra are determined on lattices up to $8^3 \\cdot 12$, and\nwe derive numerical values for fermionic determinants and results for spectral\ndensities."
    },
    {
        "anchor": "Nucleon Mass with Highly Improved Staggered Quarks: We present the first computation in a program of lattice-QCD baryon physics\nusing staggered fermions for sea and valence quarks. For this initial study, we\npresent a calculation of the nucleon mass, obtaining $964\\pm16$ MeV with all\nsources of statistical and systematic errors controlled and accounted for. This\nresult is the most precise determination to date of the nucleon mass from first\nprinciples. We use the highly-improved staggered quark action, which is\ncomputationally efficient. Three gluon ensembles are employed, which have\napproximate lattice spacings $a=0.09$ fm, $0.12$ fm, and $0.15$ fm, each with\nequal-mass $u$/$d$, $s$, and $c$ quarks in the sea. Further, all ensembles have\nthe light valence and sea $u$/$d$ quarks tuned to reproduce the physical pion\nmass, avoiding complications from chiral extrapolations or nonunitarity. Our\nwork opens a new avenue for precise calculations of baryon properties, which\nare both feasible and relevant to experiments in particle and nuclear physics.",
        "positive": "Isospin Breaking in Lattice QCD Computations of Decay Amplitudes: The remarkable recent progress in the precision of Lattice QCD computations\nfor a number of physical quantities relevant for flavour physics has motivated\nthe introduction of isospin-breaking effects, including in particular\nelectromagnetic corrections, to the computations. The isospin breaking\ncorrections are necessary to fully exploit this improved precision for the\ndetermination of the fundamental parameters of the Standard Model, including\nthe CKM matrix elements, and to look for deviations from experimental\nmeasurements which might signal the presence of new physics. Together with\ncolleagues from Rome, we have developed and implemented a framework for\nincluding isospin-breaking corrections in leptonic decays\n$P\\to\\ell\\bar\\nu_\\ell(\\gamma)$, where $P$ is a pseudoscalar meson and $\\ell$ a\ncharged lepton, and the theoretical framework and numerical results are\nreviewed below. The status of our studies to extend this framework to\nsemileptonic decays $P_1\\to P_2\\ell\\bar\\nu_\\ell(\\gamma)$, where $P_{1,2}$ are\npseudoscalar mesons, is also presented."
    },
    {
        "anchor": "Cluster Percolation and Critical Behaviour in Spin Models and SU(N)\n  Gauge Theories: The critical behaviour of several spin models can be simply described as\npercolation of some suitably defined clusters, or droplets: the onset of the\ngeometrical transition coincides with the critical point and the percolation\nexponents are equal to the thermal exponents. It is still unknown whether,\ngiven a model, one can define at all the droplets. In the cases where this is\npossible, the droplet definition depends in general on the specific model at\nstudy and can be quite involved. We propose here a simple general definition\nfor the droplets: they are clusters obtained by joining nearest-neighbour spins\nof the same sign with some bond probability p_B, which is the minimal\nprobability that still allows the existence of a percolating cluster at the\ncritical temperature T_c. By means of lattice Monte Carlo simulations we find\nthat this definition indeed satisfies the conditions required for the droplets,\nfor many classical spin models, discrete and continuous, both in two and in\nthree dimensions. In particular, our prescription allows to describe exactly\nthe confinement-deconfinement transition of SU(N) gauge theories as Polyakov\nloop percolation.",
        "positive": "The lightest $D_0^\\ast$ resonance from lattice QCD: We recently presented elastic $I=1/2$ $D\\pi$ scattering from lattice QCD at\n$m_{\\pi} = 239$ MeV. The amplitude features a pole corresponding to a mass $m\n\\approx 2200$ MeV and a width $\\Gamma \\approx 400$ MeV. The results were\ncompared to an earlier study at a higher pion mass and to a similar study in\nthe charm-strange sector. In this contribution to LATTICE2021 I summarize these\nresults and compare them with experiment, based on the values reported by the\nparticle data group. Our result lies significantly below the experimental\n$D_0^\\ast$. I also relate our findings to recent studies in chiral perturbation\ntheory. Based on work presented in JHEP2021(7),123 for the Hadron Spectrum\nCollaboration."
    },
    {
        "anchor": "Continuum reduction in large N gauge theories: These are notes associated with three lectures given at the 49th Cracow\nSchool of Theoretical physics where a pedagogical explanation of the\nGross-Witten transition, Eguchi-Kawai reduction and continuum reduction were\ngiven, followed by a description of the numerical computation of fermionic\nobservables in the 't Hooft limit of large N gauge theory.",
        "positive": "RHMC simulation of two-dimensional N=(2,2) super Yang-Mills with exact\n  supersymmetry: We report our numerical simulation of two-dimensional N=(2,2) super\nYang-Mills. The lattice model we use is one proposed by F.Sugino which keeps\none exact supersymmetry at finite lattice spacing. We use Rational Hybrid Monte\nCarlo (RHMC) method to implement the dynamical fermion. We apply the simulation\nto measure the ground state energy which is useful to observe dynamical SUSY\nbreaking."
    },
    {
        "anchor": "Modeling pion physics in the $\u03b5$-regime of two-flavor QCD using\n  strong coupling lattice QED: In order to model pions of two-flavor QCD we consider a lattice field theory\ninvolving two flavors of staggered quarks interacting strongly with U(1) gauge\nfields. For massless quarks, this theory has an $SU_L(2)\\times SU_R(2) \\times\nU_A(1)$ symmetry. By adding a four-fermion term we can break the U_A(1)\nsymmetry and thus incorporate the physics of the QCD anomaly. We can also tune\nthe pion decay constant F, to be small compared to the lattice cutoff by\nstarting with an extra fictitious dimension, thus allowing us to model low\nenergy pion physics in a setting similar to lattice QCD from first principles.\nHowever, unlike lattice QCD, a major advantage of our model is that we can\neasily design efficient algorithms to compute a variety of quantities in the\nchiral limit. Here we show that the model reproduces the predictions of chiral\nperturbation theory in the $\\epsilon$-regime.",
        "positive": "Low-energy constant $L_{10}$ in a two-representation lattice theory: We calculate the low-energy constant $L_{10}$ in a two-representation SU(4)\nlattice gauge theory that is close to a composite-Higgs model. From this we\nobtain the contribution of the new strong sector to the $S$ parameter. This\nleads to an upper bound on the vacuum misalignment parameter $\\xi$ which is\nsimilar to current estimates of this bound. Our result agrees with large-$N_c$\nscaling expectations, within large systematic uncertainties."
    },
    {
        "anchor": "Desperately Seeking Chiral Fermions: Chiral fermions can (presumably) be constructed by introducing two\nregulators, one for the gauge fields (e.g. a lattice), and another for the\nfermion functional integrals in a fixed (regulated) gauge field. This talk\ndiscusses cutoff effects arising from the regulator of the fermions.",
        "positive": "Width of the flux tube in compact U(1) gauge theory in three dimensions: We study the squared width and the profile of flux tubes in compact U(1)\nlattice gauge theory in three spacetime dimensions. The results obtained from\nnumerical calculations in the dual formulation of this confining theory are\ncompared with predictions from an effective bosonic-string model and from the\ndual-superconductor model: it is found that the former fails at describing the\nquantitative features of the flux tube, while the latter is in good agreement\nwith Monte Carlo data. The analytical interpretation of these results (in the\nlight of the semi-classical analysis by Polyakov) is pointed out, and a\ncomparison with non-Abelian gauge theories in four spacetime dimensions is\ndiscussed."
    },
    {
        "anchor": "Chimera baryon spectrum in the Sp(4) completion of composite Higgs\n  models: In strongly coupled gauge theories that serve as completions of composite\nHiggs models, the fermionic bound states formed by fermions (hyperquarks)\ntransforming in different representations, called chimera baryons, could serve\nas top partners, by embedding of the Standard Model appropriately. We report\nour results on the spectrum of chimera baryons in the Sp(4) gauge theory with\nhyperquarks transforming in fundamental and two-index antisymmetric\nrepresentations. For this study, we adopt the quenched approximation. We\ninvestigate the mass hierarchy between the lightest chimera baryons with\ndifferent quantum numbers, as a function of the lattice parameters. Inspired by\nbaryon chiral effective field theory, and the Akaike Information Criterion, we\nperform a first extrapolation to the continuum and massless-hyperquark limit.",
        "positive": "Matrix model correlation functions and lattice data for the QCD Dirac\n  operator with chemical potential: We apply a complex chiral random matrix model as an effective model to QCD\nwith a small chemical potential at zero temperature. In our model the\ncorrelation functions of complex eigenvalues can be determined analytically in\ntwo different limits, at weak and strong non-Hermiticity. We compare them to\nthe distribution of the smallest Dirac operator eigenvalues from quenched QCD\nlattice data for small values of the chemical potential, appropriately rescaled\nwith the volume. This confirms the existence of two different scaling regimes\nfrom lattice data."
    },
    {
        "anchor": "Estimation of the photon production rate using imaginary momentum\n  correlators: The thermal photon emission rate is determined by the spatially transverse,\nin-medium spectral function of the electromagnetic current. Accessing the\nspectral function using Euclidean data is, however, a challenging problem due\nto the ill-posed nature of inverting the Laplace transform. In this\ncontribution, we present the first results on implementing the proposal of\ndirectly computing the analytic continuation of the retarded correlator at\nfixed, vanishing virtuality of the photon via the calculation of the\nappropriate Euclidean correlator at imaginary spatial momentum. We employ two\ndynamical O(a)-improved Wilson fermions at a temperature of 250 MeV.",
        "positive": "Parallel implementation of a lattice-gauge-theory code: studying quark\n  confinement on PC clusters: We consider the implementation of a parallel Monte Carlo code for\nhigh-performance simulations on PC clusters with MPI. We carry out tests of\nspeedup and efficiency. The code is used for numerical simulations of pure\nSU(2) lattice gauge theory at very large lattice volumes, in order to study the\ninfrared behavior of gluon and ghost propagators. This problem is directly\nrelated to the confinement of quarks and gluons in the physics of strong\ninteractions."
    },
    {
        "anchor": "Recent Developments in Lattice QCD: I review the current status of lattice QCD results. I concentrate on new\nanalytical developments and on numerical results relevant to phenomenology.",
        "positive": "Chiral Separation Effect in lattice regularization: We consider Chiral Separation Effect (CSE) in the lattice regularized quantum\nfield theory. We discuss two types of regularization - with and without exact\nchiral symmetry. In the latter case this effect is described by its\nconventional expression for the massless fermions. This is illustrated by the\ntwo particular cases - of Wilson fermions and of the conventional overlap\nfermions. At the same time in the presence of the exact chiral symmetry the CSE\ndisappears. This is illustrated by the naive lattice fermions, when the\ncontributions of the fermion doublers cancel each other. Another example is the\nmodified version of the overlap regularization proposed recently, where there\nis the exact chiral symmetry, but as a price for this the fermion doublers\nbecome zeros of the Green function. In this case the contribution to the CSE of\nzeros and poles of the Green function cancel each other."
    },
    {
        "anchor": "Locality-constrained autoregressive cum conditional normalizing flow for\n  lattice field theory simulations: Normalizing flow-based sampling methods have been successful in tackling\ncomputational challenges traditionally associated with simulating lattice\nquantum field theories. Further works have incorporated gauge and translational\ninvariance of the action integral in the underlying neural networks, which have\nled to efficient training and inference in those models. In this paper, we\nincorporate locality of the action integral which leads to simplifications to\nthe input domain of conditional normalizing flows that sample constant time\nsub-lattices in an autoregressive process, dubbed local-Autoregressive\nConditional Normalizing Flow (l-ACNF). We find that the autocorrelation times\nof l-ACNF models outperform an equivalent normalizing flow model on the full\nlattice by orders of magnitude when sampling $\\phi^{4}$ theory on a 2\ndimensional lattice.",
        "positive": "Chiral Loop Effects in the Quenched Scalar Isovector Propagator: The scalar isovector meson propagator is studied in quenched QCD. For the\nlightest quark masses used, this propagator is dominated by a quenched chiral\nloop effect associated with the $\\eta'$-$\\pi$ two-meson intermediate state.\nBoth the time dependence and the pion mass dependence of the effect are\nwell-described by quenched chiral perturbation theory."
    },
    {
        "anchor": "Nonperturbative Regulator for Chiral Gauge Theories?: We propose a nonperturbative gauge invariant regulator for d-dimensional\nchiral gauge theories on the lattice. The method involves simulating domain\nwall fermions in d + 1 dimensions with quantum gauge fields that reside on one\nd-dimensional surface and are extended into the bulk via gradient flow. The\nresult is a theory of gauged fermions plus mirror fermions, where the mirror\nfermions couple to the gauge fields via a form factor that becomes\nexponentially soft with the separation between domain walls. The resultant\ntheory has a local d-dimensional interpretation only if the chiral fermion\nrepresentation is anomaly free. A physical realization of this construction\nwould imply the existence of mirror fermions in the standard model that are\ninvisible except for interactions induced by vacuum topology, and which could\ngravitate differently than conventional matter.",
        "positive": "Vector meson electromagnetic form factors: The charge, magnetic and quadrupole form factors of vector mesons and the\ncharge form factor of pseudo-scalar mesons are calculated in quenched lattice\nQCD. The charge radii and magnetic moments are derived. The quark sector\ncontributions to the form factors are calculated separately and we highlight\nthe environmental sensitivity of the light-quark contribution to charge radii."
    },
    {
        "anchor": "The eta-prime propagator in quenched QCD: The calculation of the eta-prime hairpin diagram is carried out in the\nmodified quenched approximation (MQA) in which the lattice artifact which\ncauses exceptional configurations is removed by shifting observed poles at\nkappa<kappa_c in the quark propagators to the critical value of hop ping\nparameter. By this method, the eta-prime propagator can be accurately\ncalculated even for very light quark mass. A determination of the topological\nsusceptibility for quenched QCD is also obtained, using the fermionic method of\nSmit and Vink to calculate winding numbers.",
        "positive": "Trace anomaly and dynamical quark mass: We investigated the origin of the RI'/MOM quark mass under the Landau gauge\nat the non-perturbative scale, using the chiral fermion with different quark\nmasses and lattice spacings. Our result confirms that such a mass is\nnon-vanishing based on the linear extrapolation to the chiral and continuum\nlimit, and shows that such a mass comes from the spontaneous chiral symmetry\nbreaking induced by the near zero modes with the eigenvalue $\\lambda<{\\cal\nO}(5m_q)$, and is proportional to the quark matrix element of the trace anomaly\nat least down to $\\sim $1.3 GeV."
    },
    {
        "anchor": "A new computational approach to lattice quantum field theories: Developments in algorithms over the past decade suggest that there is a new\ncomputational approach to a class of quantum field theories. This approach is\nbased on rewriting the partition function in a representation similar to the\nworld-line representation and hence we shall call it the \"WL-approach\". This\napproach is likely to be more powerful than the conventional approach in some\nregions of parameter space, especially in the presence of chemical potentials\nor massless fermions. While world-line representations are natural in the\nHamiltonian formulation, they can also be constructed directly in Euclidean\nspace. We first describe the approach and its advantages by considering the\nclassical XY model in the presence of a chemical potential. We then argue that,\n$CP^{N-1}$ models, models of pions on the lattice and the lattice massless\nThirring model, can all be formulated and solved using the WL-approach. In\nparticular, we discover that the WL-approach to the Thirring model leads to a\nnovel determinantal Monte-Carlo algorithm which we call the \"dynamical-bag\"\nalgorithm. Finally, we argue that a simple extension of the WL-approach to\ngauge theories leads to a world-sheet, \"WS-approach\", in Abelian Lattice Gauge\ntheory.",
        "positive": "Thermal evolution of the one-flavour Schwinger model using Matrix\n  Product States: The Schwinger model, or 1+1 dimensional QED, offers an interesting object of\nstudy, both at zero and non-zero temperature, because of its similarities to\nQCD. In this proceeding, we present the a full calculation of the temperature\ndependent chiral condensate of this model in the continuum limit using Matrix\nProduct States (MPS). MPS methods, in general tensor networks, constitute a\nvery promising technique for the non-perturbative study of Hamiltonian quantum\nsystems. In the last few years, they have shown their suitability as ansatzes\nfor ground states and low-lying excita- tions of lattice gauge theories. We\nshow the feasibility of the approach also for finite temperature, both in the\nmassless and in the massive case."
    },
    {
        "anchor": "Sampling QCD field configurations with gauge-equivariant flow models: Machine learning methods based on normalizing flows have been shown to\naddress important challenges, such as critical slowing-down and topological\nfreezing, in the sampling of gauge field configurations in simple lattice field\ntheories. A critical question is whether this success will translate to studies\nof QCD. This Proceedings presents a status update on advances in this area. In\nparticular, it is illustrated how recently developed algorithmic components may\nbe combined to construct flow-based sampling algorithms for QCD in four\ndimensions. The prospects and challenges for future use of this approach in\nat-scale applications are summarized.",
        "positive": "K -> pi l nu form factors with staggered quarks: We report on the status of the Fermilab-MILC calculation of the form factor\nf_+^{K pi}(0), needed to extract the CKM matrix element |V_{us}| from\nexperimental data on K semileptonic decays. The HISQ formulation is used in the\nsimulations for the valence quarks, while the sea quarks are simulated with the\nasqtad action (MILC N_f=2+1 configurations). We discuss the general methodology\nof the calculation, including the use of twisted boundary conditions to get\nvalues of the momentum transfer close to zero and the different techniques\napplied for the correlators fits. We present initial results for lattice\nspacings a=0.12fm and a=0.09fm, and several choices of the light quark masses."
    },
    {
        "anchor": "Continuum limit of the axial anomaly and index for the staggered overlap\n  Dirac operator: An overview: Evaluation of the continuum limit of the axial anomaly and index is sketched\nfor the staggered overlap Dirac operator. There are new complications compared\nto the usual overlap case due to the distribution of the spin and flavor\ncomponents around lattice hypercubes in the staggered formalism. The index is\nfound to correctly reproduce the continuum index, but for the axial anomaly\nthis is only true after averaging over the sites of a lattice hypercube.",
        "positive": "The strange quark condensate in the nucleon in 2+1 flavor QCD: We calculate the \"strange quark content of the nucleon\", <N| s s_bar |N>,\nwhich is important for interpreting the results of some dark matter detection\nexperiments. The method is to evaluate quark-line disconnected correlations on\nthe MILC lattice ensembles, which include the effects of dynamical strange\nquarks. After continuum and chiral extrapolations, the result is <N |s s_bar\n|N> = 0.69 +- 0.07(statistical) +- 0.09(systematic), in the modified minimal\nsubtraction scheme (2 GeV), or for the renormalization scheme invariant form,\nm_s partial{M_N}/partial{m_s} = 59(6)(8) MeV."
    },
    {
        "anchor": "Invariant measure in hot gauge theories: We investigate properties of the invariant measure for the $A_0$ gauge field\nin finite temperature gauge theories both on the lattice and in the continuum\ntheory. We have found the cancellation of the naive measure in both cases. The\nresult is quite general and holds at any finite temperature. We demonstrate,\nhowever, that there is no cancellation at any temperature for the invariant\nmeasure contribution understood as Z(N) symmetrical distribution of gauge field\nconfigurations. The spontaneous breakdown of Z(N) global symmetry is entirely\ndue to the potential energy term of the gluonic interaction in the effective\npotential. The effects of this measure on the effective action, mechanism of\nconfinement and $A_0$ condensation are discussed.",
        "positive": "Confinement and the quark Fermi-surface in SU(2N) QCD-like theories: Yang-Mills theories with a gauge group SU(N_c\\=3)and quark matter in the\nfundamental representation share many properties with the theory of strong\ninteractions, QCD with N_c=3. We show that, for N_c even and in the confinement\nphase, the gluonic average of the quark determinant is independent of the\nboundary conditions, periodic or anti-periodic ones. We then argue that a Fermi\nsphere of quarks can only exist under extreme conditions when the centre\nsymmetry is spontaneously broken and colour is liberated. Our findings are\nsupported by lattice gauge simulations for N_c=2...5 and are illustrated by\nmeans of a simple quark model."
    },
    {
        "anchor": "Exploring Complex-Langevin Methods for Finite-Density QCD: QCD at non-zero chemical potential ($\\mu$) for quark number has a complex\nfermion determinant and thus standard simulation methods for lattice QCD cannot\nbe applied. We therefore simulate this theory using the Complex-Langevin\nalgorithm with Gauge Cooling in addition to adaptive methods, to prevent\nrunaway behaviour. Simulations are performed at zero temperature on a $12^4$\nlattice with 2 quarks which are light enough that $m_N/3$ is significantly\nlarger than $m_\\pi/2$. Preliminary results are qualitatively as expected. The\nquark-number density is close to zero for $\\mu < m_N/3$, beyond which it\nincreases, eventually reaching its saturation value of $3$ for $\\mu$\nsufficiently large. The chiral condensate decreases as $\\mu$ is increased\napproaching zero at saturation, while the plaquette increases towards its\nquenched value. We have yet to observe the transition to nuclear matter at $\\mu\n\\approx m_N/3$, presumably because the runs for $\\mu$ between $m_N/3$ and\nsaturation have yet to equilibrate.",
        "positive": "Study of the finite temperature transition in 3-flavor QCD using the R\n  and RHMC algorithms: We study the finite temperature transition in QCD with three flavors of equal\nmasses using the R and RHMC algorithm on lattices with temporal extent\nN_{\\tau}=4 and 6. For the transition temperature in the continuum limit we find\nr_0 T_c=0.429(8) for the light pseudo-scalar mass corresponding to the end\npoint of the 1st order transition region. When comparing the results obtained\nwith the R and RHMC algorithms for p4fat3 action we see no significant\nstep-size errors down to a lightest pseudo-scalar mass of m_{ps} r_0=0.4."
    },
    {
        "anchor": "Chiral and Continuum Extrapolation of Partially-Quenched Hadron Masses: Using the finite-range regularisation (FRR) of chiral effective field theory,\nthe chiral extrapolation formula for the vector meson mass is derived for the\ncase of partially-quenched QCD. We re-analyse the dynamical fermion QCD data\nfor the vector meson mass from the CP-PACS collaboration. A global fit,\nincluding finite lattice spacing effects, of all 16 of their ensembles is\nperformed. We study the FRR method together with a naive polynomial approach\nand find excellent agreement ~1% with the experimental value of M_rho from the\nformer approach. These results are extended to the case of the nucleon mass.",
        "positive": "K to pi pi Amplitudes at Unphysical Kinematics Using Domain Wall\n  Fermions: The use of chiral perturbation theory in extracting physical K to pi pi\nmatrix elements from matrix elements calculated at unphysical kinematics is\noutlined. In particular, the possibility of utilizing pions with non-zero\nmomentum in the final state, and of using partial quenching is discussed.\nPreliminary (not physically normalized) Delta I=3/2 (27,1) K to pi pi matrix\nelements are calculated on the RBC/UKQCD $24^3 \\times 64$, $L_s=16$ lattices,\nusing 2+1 dynamical flavors and domain wall fermions, with an inverse lattice\nspacing of $a^{-1}=1.729(28) GeV$. Effective mass plots are presented for a\nlight sea quark mass of $m_l^{sea}=0.005$, and various valence quark masses.\nThe plateaux are fit and $E_{\\pi\\pi}-m_K$ is extracted."
    },
    {
        "anchor": "A determination of the strange quark mass for unquenched clover fermions\n  using the AWI: Using the O(a) Symanzik improved action an estimate is given for the strange\nquark mass for unquenched (nf=2) QCD. The determination is via the axial Ward\nidentity (AWI) and includes a non-perturbative evaluation of the\nrenormalisation constant. Numerical results have been obtained at several\nlattice spacings, enabling the continuum limit to be taken. Results indicate a\nvalue for the strange quark mass (in the MSbar-scheme at a scale of 2GeV) in\nthe range 100 - 130MeV.",
        "positive": "$B_s\\to K\\ell\u03bd$ decay from lattice QCD: We use lattice QCD to calculate the form factors $f_+(q^2)$ and $f_0(q^2)$\nfor the semileptonic decay $B_s\\to K\\ell\\nu$. Our calculation uses six MILC\nasqtad 2+1 flavor gauge-field ensembles with three lattice spacings. At the\nsmallest and largest lattice spacing the light-quark sea mass is set to 1/10\nthe strange-quark mass. At the intermediate lattice spacing, we use four values\nfor the light-quark sea mass ranging from 1/5 to 1/20 of the strange-quark\nmass. We use the asqtad improved staggered action for the light valence quarks,\nand the clover action with the Fermilab interpolation for the heavy valence\nbottom quark. We use SU(2) hard-kaon heavy-meson rooted staggered chiral\nperturbation theory to take the chiral-continuum limit. A functional $z$\nexpansion is used to extend the form factors to the full kinematic range. We\npresent predictions for the differential decay rate for both $B_s\\to K\\mu\\nu$\nand $B_s\\to K\\tau\\nu$. We also present results for the forward-backward\nasymmetry, the lepton polarization asymmetry, ratios of the scalar and vector\nform factors for the decays $B_s\\to K\\ell\\nu$ and $B_s\\to D_s \\ell\\nu$. Our\nresults, together with future experimental measurements, can be used to\ndetermine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element\n$|V_{ub}|$."
    },
    {
        "anchor": "The Euclidean Spectrum of Kaplan's Lattice Chiral Fermions: We consider the (2n+1)-dimensional euclidean Dirac operator with a mass term\nthat looks like a domain wall, recently proposed by Kaplan to describe chiral\nfermions in $2n$ dimensions. In the continuum case we show that the euclidean\nspectrum contains {\\it no} bound states with non-zero momentum. On the lattice,\na bound state spectrum without energy gap exists only if $m$ is fine tuned to\nsome special values, and the dispersion relation does not describe a\nrelativistic fermion. In spite of these peculiarities, the fermionic propagator\n{\\it has} the expected (1/p-slash) pole on the domain wall. But there may be a\nproblem with the phase of the fermionic determinant at the non-perturbative\nlevel.",
        "positive": "QCD phase diagram at strong coupling including auxiliary field\n  fluctuations: We investigate the phase diagram and the mechanism for the sign problem to\nappear in finite density QCD at strong coupling in a combined framework of the\nauxiliary field Monte-Carlo (AFMC) and the chiral angle fixing (CAF) methods.\nWhen bosonizing meson hopping terms in the effective action, we need to\nintroduce imaginary number coefficients, which leads to a complex phase in\nnumerical simulations. By using the cut-off technique, we quantitatively show\nthat high momentum modes of auxiliary fields mainly contribute to the weight\ncancellation; Cutting-off high-momentum auxiliary field modes does not modify\norder parameters but suppresses statistical weight cancellation, when we choose\nthe cut-off parameter appropriately."
    },
    {
        "anchor": "Lattice Gauge Theory - A short Primer: In this contribution we give an introduction to the foundations and methods\nof lattice gauge theory. Starting with a brief discussion of the quantum\nmechanical path integral, we develop the main ingredients of lattice field\ntheory: functional integrals, Euclidean field theory and the space-time\ndiscretization of scalar, fermion and gauge fields. Some of the methods used in\ncalculations are reviewed and illustrated by a collection of typical results.",
        "positive": "Non-perturbative Renormalisation of Domain Wall Fermions: Quark\n  Bilinears: We find the renormalisation coefficients of the quark field and the flavour\nnon-singlet fermion bilinear operators for the domain wall fermion action, in\nthe regularisation independent (RI) renormalisation scheme. Our results are\nfrom a quenched simulation, on a 16^3x32 lattice, with beta=6.0 and an extent\nin the fifth dimension of 16. We also discuss the expected effects of the\nresidual chiral symmetry breaking inherent in a domain wall fermion simulation\nwith a finite fifth dimension, and study the evidence for both explicit and\nspontaneous chiral symmetry breaking effects in our numerical results. We find\nthat the relations between different renormalisation factors predicted by\nchiral symmetry are, to a good approximation, satisfied by our results and that\nsystematic effects due to the (low energy) spontaneous chiral symmetry breaking\nand zero-modes can be controlled. Our results are compared against the\nperturbative predictions for both their absolute value and renormalisation\nscale dependence."
    },
    {
        "anchor": "Studying and removing effects of fixed topology: At small lattice spacing, or when using overlap fermions, lattice QCD\nsimulations tend to become stuck in a single topological sector. Physical\nobservables, e.g.\\ hadron masses, then differ from their full QCD counterparts\nby $1/V$ corrections, where $V$ is the spacetime volume. These corrections can\nbe calculated order by order using the saddle point method. We calculate all\ncorrections proportional to $1/V^2$ and $1/V^3$ and test the resulting\nequations for several models: a quantum mechanical particle on a circle, the\nSchwinger model and SU(2) Yang-Mills theory.",
        "positive": "The curvature of the chiral pseudocritical line from LQCD: analytic\n  continuation and Taylor expansion compared: We present a determination of the curvature $\\kappa$ of the chiral\npseudocritical line from $N_f=2+1$ lattice QCD at the physical point obtained\nby adopting the Taylor expansion approach. Numerical simulations performed at\nthree lattice spacings lead to a continuum extrapolated curvature $\\kappa =\n0.0145(25)$, a value that is in excellent agreement with continuum limit\nestimates obtained via analytic continuation within the same discretization\nscheme, $\\kappa = 0.0135(20)$. The agreement between the two calculations is a\nsolid consistency check for both methods."
    },
    {
        "anchor": "Spectroscopy and Decay Constants from Nonperturbative HQET at Order 1/m: We carry out a thorough analysis with the GEVP method to obtain ground-state\nand first-excited-state masses and decay constants of bottom-strange\n(pseudo-scalar and vector) mesons. This computation is done for quenched,\nnonperturbatively renormalized HQET, including order $1/m_b$ terms. The\ncontinuum limit is obtained using three lattice spacings and two static\nactions.",
        "positive": "Domain wall fermions with Majorana couplings: We examine the lattice boundary formulation of chiral fermions with either an\nexplicit Majorana mass or a Higgs-Majorana coupling introduced on one of the\nboundaries. We demonstrate that the low-lying spectrum of the models with an\nexplicit Majorana mass of the order of an inverse lattice spacing is chiral at\ntree level. Within a mean-field approximation we show that the systems with a\nstrong Higgs-Majorana coupling have a symmetric phase, in which a Majorana mass\nof the order of an inverse lattice spacing is generated without spontaneous\nbreaking of the gauge symmetry. We argue, however, that the models within such\na phase have a chiral spectrum only in terms of the fermions that are singlets\nunder the gauge group. The application of such systems to nonperturbative\nformulations of supersymmetric and chiral gauge theories is briefly discussed."
    },
    {
        "anchor": "Light quark spectrum with improved gauge and fermion actions: We report on a study of the light quark spectrum using an improved gauge\naction and both Kogut-Susskind and Naik quark actions. We have studied six\ndifferent lattice spacings, corresponding to plaquette couplings ranging from\n6.8 to 7.9, with five to six quark masses per coupling. We compare the two\nquark actions in terms of the spectrum and restoration of flavor symmetry. We\nalso compare these results with those from the conventional action.",
        "positive": "Residual meson-meson interaction from lattice gauge simulation in a\n  simple QED model: The residual interaction for a meson-meson system is computed utilizing the\ncumulant, or cluster, expansion of the momentum-space time correlation matrix.\nThe cumulant expansion serves to define asymptotic, or free, meson-meson\noperators. The definition of an effective interaction is then based on a\ncomparison of the full (interacting) and the free (noninteracting) time\ncorrelation matrices. The proposed method, which may straightforwardly be\ntranscribed to other hadron-hadron systems, here is applied to a simple 2+1\ndimensional U(1) lattice gauge model tuned such that it is confining. Fermions\nare treated in the staggered scheme. The effective interaction exhibits a\nrepulsive core and attraction at intermediate relative distances. These\nfindings are consistent with an earlier study of the same model utilizing\nL\\\"{u}scher's method where scattering phase shifts are obtained directly."
    },
    {
        "anchor": "The D to K and D to pi semileptonic decay form factors from Lattice QCD: We present a new and very high statistics study of D and D_s semileptonic\ndecay form factors on the lattice. We work with MILC N_f=2+1 lattices and use\nthe Highly Improved Staggered Action (HISQ) for both the charm and the light\nvalence quarks. We use both scalar and vector currents to determine the form\nfactors f_0(q^2) and f_+(q^2) for a range of D and D_s form factors including\nthose for D to pi and D to K semileptonic decays. By using a phased boundary\ncondition we are able to tune accurately to q^2=0. We also compare the shape in\nq^2 to that from experiment. We show that the form factors are very insensitive\nto the spectator quark: D to K and D_s to eta_s form factors are essentially\nthe same, and the same is true for D to pi and D_s to K. This has important\nimplications when considering the corresponding B/B_s processes.",
        "positive": "Quasi-asymptotic freedom in the two dimensional O(3) model: The behaviour of the renormalized spin 2-point function in the O(3) and\ndodecahedron spin model are investigated numerically. The Monte Carlo data show\nexcellent agreement between the two models. The short distance behavior comes\nvery close to standard theoretical expectations, yet it differs significantly\nfrom it. A possible explanation of this situation is offered."
    },
    {
        "anchor": "Approaching the Chiral and Continuum Limit of Large-N QCD: We present preliminary results from our calculation of the low energy\nconstants (LECs) of the chiral effective theory for 3, 4 and 5 color QCD with\n$N_f=2$ dynamical fermion flavors. We simulate with clover fermions over a\nrange of lattice couplings and quark masses. We observe the expected $N_c$\nscaling for the LECs appropriate to the condensate $B$ and pseudoscalar decay\nconstant $F$. The range of quark masses over which leading order chiral\nperturbation theory describes the data grows as $N_c$ rises.",
        "positive": "Lattice $\u03c6^4$ Field Theory on Riemann Manifolds: Numerical Tests for\n  the 2-d Ising CFT on $\\mathbb{S}^2$: We present a method for defining a lattice realization of the $\\phi^4$\nquantum field theory on a simplicial complex in order to enable numerical\ncomputation on a general Riemann manifold. The procedure begins with adopting\nmethods from traditional Regge Calculus (RC) and finite element methods (FEM)\nplus the addition of ultraviolet counter terms required to reach the\nrenormalized field theory in the continuum limit. The construction is tested\nnumerically for the two-dimensional $\\phi^4$ scalar field theory on the Riemann\ntwo-sphere, $\\mathbb{S}^2$, in comparison with the exact solutions to the\ntwo-dimensional Ising conformal field theory (CFT). Numerical results for the\nBinder cumulants (up to 12th order) and the two- and four-point correlation\nfunctions are in agreement with the exact $c = 1/2$ CFT solutions."
    },
    {
        "anchor": "Effective Field Theories: Effective field theories encode the predictions of a quantum field theory at\nlow energy. The effective theory has a fairly low ultraviolet cutoff. As a\nresult, loop corrections are small, at least if the effective action contains a\nterm which is quadratic in the fields, and physical predictions can be read\nstraight from the effective Lagrangean.\n  Methods will be discussed how to compute an effective low energy action from\na given fundamental action, either analytically or numerically, or by a\ncombination of both methods. Basically,the idea is to integrate out the high\nfrequency components of fields. This requires the choice of a \"blockspin\",i.e.\nthe specification of a low frequency field as a function of the fundamental\nfields. These blockspins will be the fields of the effective field theory. The\nblockspin need not be a field of the same type as one of the fundamental\nfields, and it may be composite. Special features of blockspins in nonabelian\ngauge theories will be discussed in some detail.\n  In analytical work and in multigrid updating schemes one needs interpolation\nkernels $\\A$ from coarse to fine grid in addition to the averaging kernels $C$\nwhich determines the blockspin. A neural net strategy for finding optimal\nkernels is presented.\n  Numerical methods are applicable to obtain actions of effective theories on\nlattices of finite volume. The constraint effective potential) is of particular\ninterest. In a Higgs model it yields the free energy, considered as a function\nof a gauge covariant magnetization. Its shape determines the phase structure of\nthe theory. Its loop expansion with and without gauge fields can be used to\ndetermine finite size corrections to numerical data.",
        "positive": "String confinement in 2-form lattice gauge theory: We study the confinement between vortex strings in the dual lattice gauge\ntheory of the abelian Higgs model. The dual lattice gauge theory is described\nby a 2-form gauge field. We calculate the string-antistring potential from the\nsurface operator of the 2-form gauge field. The linear confining potential\nappears in a confinement phase and it disappears in a deconfinement phase. The\nphase diagram of the theory is also obtained."
    },
    {
        "anchor": "Lattice QCD Calculation of the Pion Mass Splitting: We use the infinite volume reconstruction method to calculate the\ncharged/neutral pion mass difference. The hadronic tensor is calculated on\nlattice QCD and then combined with an analytic photon propagator, and the mass\nsplitting is calculated with exponentially-suppressed finite volume errors. The\ncalculation is performed using six gauge ensembles generated with $2+1$-flavor\ndomain wall fermions, and five ensembles are at the physical pion mass. Both\nFeynman and Coulomb gauge are adopted in the calculation and result in a good\nagreement when the lattice spacing approaches zero. After performing the\ncontinuum extrapolation and examining the residual finite-volume effects, we\nobtain the pion mass splitting $\\Delta m_\\pi = 4.534(42)(43)~\\mathrm{MeV}$,\nwhich agrees well with experimental measurements.",
        "positive": "Glueballs and Strings in $Sp(2N)$ Yang-Mills theories: Motivated in part by the pseudo-Nambu Goldstone Boson mechanism of\nelectroweak symmetry breaking in Composite Higgs Models, in part by dark matter\nscenarios with strongly coupled origin, as well as by general theoretical\nconsiderations related to the large-N extrapolation, we perform lattice studies\nof the Yang-Mills theories with $Sp(2N)$ gauge groups. We measure the string\ntension and the mass spectrum of glueballs, extracted from appropriate 2-point\ncorrelation functions of operators organised as irreducible representations of\nthe octahedral symmetry group. We perform the continuum extrapolation and study\nthe magnitude of finite-size effects, showing that they are negligible in our\ncalculation. We present new numerical results for $N=1$, $2$, $3$, $4$, combine\nthem with data previously obtained for $N=2$, and extrapolate towards\n$N\\rightarrow \\infty$. We confirm explicitly the expectation that, as already\nknown for $N=1,2$ also for $N=3,4$ a confining potential rising linearly with\nthe distance binds a static quark to its antiquark. We compare our results to\nthe existing literature on other gauge groups, with particular attention\ndevoted to the large-$N$ limit. We find agreement with the known values of the\nmass of the $0^{++}$, $0^{++*}$ and $2^{++}$ glueballs obtained taking the\nlarge-$N$ limit in the $SU(N)$ groups. In addition, we determine for the first\ntime the mass of some heavier glueball states at finite $N$ in $Sp(2N)$ and\nextrapolate the results towards $N \\rightarrow +\\infty$ taking the limit in the\nlatter groups. Since the large-$N$ limit of $Sp(2N)$ is the same as in $SU(N)$,\nour results are relevant also for the study of QCD-like theories."
    },
    {
        "anchor": "New Domain-Wall Fermion Actions: In perturbation theory, the wave function of domain-wall quarks decreases\nexponentially with the fifth coordinate. We show that, regardless of the\nquark's own momentum, the fall-off rate of the one-loop wave function is equal\nto the slowest rate encountered at tree-level for any lattice four-momentum. We\npropose new domain-wall actions involving beyond-nearest neighbor couplings in\nthe four physical dimensions, for which the perturbative wave function\ndecreases much faster. It is hoped that the new actions may preserve the good\nchiral properties of domain-wall fermions up to larger values of the lattice\nspacing.",
        "positive": "Landau gauge fixing on the lattice using GPU's: In this work, we consider the GPU implementation of the steepest descent\nmethod with Fourier acceleration for Laudau gauge fixing, using CUDA. The\nperformance of the code in a Tesla C2070 GPU is compared with a parallel CPU\nimplementation."
    },
    {
        "anchor": "Renormalisation constants of quark bilinears in lattice QCD with four\n  dynamical Wilson quarks: We present preliminary results of the non-perturbative computation of the\nRI-MOM renormalisation constants in a mass-independent scheme for the action\nwith Iwasaki glue and four dynamical Wilson quarks employed by ETMC. Our\nproject requires dedicated gauge ensembles with four degenerate sea quark\nflavours at three lattice spacings and at several values of the standard and\ntwisted quark mass parameters. The RI-MOM renormalisation constants are\nobtained from appropriate O(a) improved estimators extrapolated to the chiral\nlimit.",
        "positive": "Constructing non-perturbative gauges using correlation functions: Gauge fixing in the non-perturbative domain of non-Abelian gauge theories is\nobstructed by the Gribov-Singer ambiguity. To compare results from different\nmethods it is necessary to resolve this ambiguity explicitly. Such a resolution\nis proposed using conditions on correlation functions for a family of\nnon-perturbative Landau gauges. As a consequence, the various results available\nfor correlation functions could possibly correspond to different\nnon-perturbative Landau gauges, discriminated by an additional non-perturbative\ngauge parameter. The proposal, the necessary assumptions, and evidence from\nlattice gauge theory calculations, are presented in detail."
    },
    {
        "anchor": "B- and D-meson decay constants from three-flavor lattice QCD: We calculate the leptonic decay constants of B_{(s)} and D_{(s)} mesons in\nlattice QCD using staggered light quarks and Fermilab bottom and charm quarks.\nWe compute the heavy-light meson correlation functions on the MILC\nasqtad-improved staggered gauge configurations which include the effects of\nthree light dynamical sea quarks. We simulate with several values of the light\nvalence- and sea-quark masses (down to ~m_s/10) and at three lattice spacings\n(a ~ 0.15, 0.12, and 0.09 fm) and extrapolate to the physical up and down quark\nmasses and the continuum using expressions derived in heavy-light meson\nstaggered chiral perturbation theory. We renormalize the heavy-light axial\ncurrent using a mostly nonperturbative method such that only a small correction\nto unity must be computed in lattice perturbation theory and higher-order terms\nare expected to be small. We obtain f_{B^+} = 196.9(8.9) MeV, f_{B_s} =\n242.0(9.5) MeV, f_{D^+} = 218.9(11.3) MeV, f_{D_s} = 260.1(10.8) MeV, and the\nSU(3) flavor-breaking ratios f_{B_s}/f_{B} = 1.229(26) and f_{D_s}/f_{D} =\n1.188(25), where the numbers in parentheses are the total statistical and\nsystematic uncertainties added in quadrature.",
        "positive": "Asymptotic safety on the lattice: The Nonlinear O(N) Sigma Model: We study the non-perturbative renormalization group flow of the nonlinear\nO(N) sigma model in two and three spacetime dimensions using a scheme that\ncombines an effective local Hybrid Monte Carlo update routine, blockspin\ntransformations and a Monte Carlo demon method. In two dimensions our results\nverify perturbative renormalizability. In three dimensions, we determine the\nflow diagram of the theory for various $N$ and different truncations and find a\nnon-trivial fixed point, which indicates non-perturbative renormalizability. It\nis related to the well-studied phase transition of the O(N) universality class\nand characterizes the continuum physics of the model. We compare the obtained\nrenormalization group flows with recent investigations by means of the\nFunctional Renormalization Group."
    },
    {
        "anchor": "Distance preconditioning for lattice Dirac operators: We propose a preconditioning of the Dirac operator based on the factorisation\nof a predefined function related to the decay of the propagator with the\ndistance. We show that it can improve the accuracy of correlators involving\nheavy quarks at large distances and accelerate the computation of light quark\npropagators.",
        "positive": "Lattice QCD calculation of hadronic light-by-light scattering: We perform a lattice QCD calculation of the hadronic light-by-light\nscattering amplitude in a broad kinematical range. At forward kinematics, the\nresults are compared to a phenomenological analysis based on dispersive sum\nrules for light-by-light scattering. The size of the pion pole contribution is\ninvestigated for momenta of typical hadronic size. The presented numerical\nmethods can be used to compute the hadronic light-by-light contribution to the\nanomalous magnetic moment of the muon. Our calculations are carried out in\ntwo-flavor QCD with the pion mass in the range of 270 to 450MeV, and contain so\nfar only the diagrams with fully connected quark lines."
    },
    {
        "anchor": "QED self energies from lattice QCD without power-law finite-volume\n  errors: Using the infinite-volume photon propagator, we developed a method which\nallows us to calculate electromagnetic corrections to stable hadron masses with\nonly exponentially suppressed finite-volume effects. The key idea is that the\ninfinite volume hadronic current-current correlation function with large time\nseparation between the two currents can be reconstructed by its value at modest\ntime separation, which can be evaluated in finite volume with only\nexponentially suppressed errors. This approach can be extended to other\npossible applications such as QED corrections to (semi-)leptonic decays and\nsome rare decays.",
        "positive": "Lattice study of monopoles in the Electroweak theory: We investigated numerically properties of Nambu monopoles in lattice\nElectroweak theory at realistic values of $\\alpha$ and $\\theta_W$. Our choice\nof parameters of lattice Lagrangian corresponds to large values of the Higgs\nboson mass $M_H > 2 M_W$.\n  We find that the density of Nambu monopoles cannot be predicted by the choice\nof the initial parameters of Electroweak theory and should be considered as the\nnew external parameter of the theory. We also investigate the difference\nbetween the versions of Electroweak theory with the gauge groups $SU(2)\\otimes\nU(1)$ and $SU(2)\\otimes U(1)/Z_2$. We do not detect any difference at $\\alpha\n\\sim {1/128}$. However, such a difference appears in the strong coupling region\nand is related to the properties of monopoles constructed of the hypercharge\nfield."
    },
    {
        "anchor": "N to Delta transition form factors with Nf=2+1 domain wall fermions: The electromagnetic, axial and pseudoscalar nucleon to Delta form factors are\ncalculated using dynamical domain wall fermions at a lattice spacing of a =\n0.114 fm on a lattice of spatial size 2.74 fm and pion mass of 331 MeV. Pion\npole dominance and the Goldberger-Treiman relations are examined.",
        "positive": "Heavy baryon spectrum on lattice with NRQCD bottom and HISQ lighter\n  quarks: We determine the mass spectra of heavy baryons containing one or more bottom\nquarks along with their hyperfine splittings and various mass differences on\nMILC 2+1 Asqtad lattices at three different lattice spacings. NRQCD action is\nused for bottom quarks whereas relativistic HISQ action for the lighter\nup/down, strange and charm quarks. We consider all possible combinations of\nbottom and lighter quarks to construct the bottom baryon operators for the\nstates $J^P=1/2^+$ and $3/2^+$."
    },
    {
        "anchor": "AVX-512 extension to OpenQCD 1.6: We publish an extension of openQCD-1.6 with AVX-512 vector instructions using\nIntel intrinsics. Recent Intel processors support extended instruction sets\nwith operations on 512-bit wide vectors, increasing both the capacity for\nfloating point operations and register memory. Optimal use of the new\ncapabilities requires reorganising data and floating point operations into\nthese wider vector units. We report on the implementation and performance of\nthe AVX-512 OpenQCD extension on clusters using Intel Knights Landing and Xeon\nScalable (Skylake) CPUs. In complete HMC trajectories with physically relevant\nparameters we observe a performance increase of 5% to 10%.",
        "positive": "Vortex free energies in SO(3) and SU(2) lattice gauge theory: Lattice gauge theories with gauge groups SO(3) and SU(2) are compared. The\nfree energy of electric twist, an order parameter for the\nconfinement-deconfinement transition which does not rely on centre-symmetry\nbreaking, is measured in both theories. The results are used to calibrate the\nscale in SO(3)."
    },
    {
        "anchor": "P-vortices and Drama of Gribov Copies: We present results of the careful study of the Gribov copies problem in SU(2)\nlattice gauge theory for the direct maximal center projection widely used in\nconfinement studies. Applying simulated annealing algorithm we demonstrate that\nthis problem is more severe than it was thought before. The projected (gauge\nnoninvariant) string tension is not in the agreement with the physical string\ntension. We do not find any indications that P-vortices reproduce the full\nSU(2) string tension neither in the infinite volume limit nor in the continuum\nlimit.",
        "positive": "A status report of the QCDSF $N_f=2+1$ Project: We report about on-going simulations of $N_f=2+1$ lattice QCD. We use a\ntadpole improved Symanzik gauge action and stout link smeared Wilson fermions\nwith a clover term. We employ the Hasenbusch trick for the degenerate u- and\nd-quarks, and the RHMC algorithm for the simulation of the strange quark."
    },
    {
        "anchor": "Automatic generation of vertices for the Schroedinger functional: We present a multiplication algorithm to recursively construct vertices for\nthe Schroedinger functional in the abelian background field case. The algorithm\nis suited for automatic perturbative calculations with a variety of actions. As\nfirst applications, we derive ratios of the lambda parameters between the\nlattice scheme (improved gauge actions including six link loops) and the\n$\\bar{\\rm MS}$ scheme, and one-loop results for the Schroedinger functional\ncoupling with a lattice $T=L \\pm a$, which is motivated by considering\nstaggered fermions.",
        "positive": "Vector and Axial Currents in Wilson Chiral Perturbation Theory: We reconsider the construction of the vector and axial-vector currents in\nWilson Chiral Perturbation Theory (WChPT), the low-energy effective theory for\nlattice QCD with Wilson fermions. We discuss in detail the finite\nrenormalization of the currents that has to be taken into account in order to\nproperly match the currents. We explicitly show that imposing the chiral Ward\nidentities on the currents does, in general, affect the axial-vector current at\nO(a). As an application of our results we compute the pion decay constant to\none loop in the two flavor theory. Our result differs from previously published\nones."
    },
    {
        "anchor": "The Quantized $O(1,2)/O(2)\\times Z_2$ Sigma Model Has No Continuum Limit\n  in Four Dimensions. I. Theoretical Framework: The nonlinear sigma model for which the field takes its values in the coset\nspace $O(1,2)/O(2)\\times Z_2$ is similar to quantum gravity in being\nperturbatively nonrenormalizable and having a noncompact curved configuration\nspace. It is therefore a good model for testing nonperturbative methods that\nmay be useful in quantum gravity, especially methods based on lattice field\ntheory. In this paper we develop the theoretical framework necessary for\nrecognizing and studying a consistent nonperturbative quantum field theory of\nthe $O(1,2)/O(2)\\times Z_2$ model. We describe the action, the geometry of the\nconfiguration space, the conserved Noether currents, and the current algebra,\nand we construct a version of the Ward-Slavnov identity that makes it easy to\nswitch from a given field to a nonlinearly related one. Renormalization of the\nmodel is defined via the effective action and via current algebra. The two\ndefinitions are shown to be equivalent. In a companion paper we develop a\nlattice formulation of the theory that is particularly well suited to the sigma\nmodel, and we report the results of Monte Carlo simulations of this lattice\nmodel. These simulations indicate that as the lattice cutoff is removed the\ntheory becomes that of a pair of massless free fields. Because the geometry and\nsymmetries of these fields differ from those of the original model we conclude\nthat a continuum limit of the $O(1,2)/O(2)\\times Z_2$ model which preserves\nthese properties does not exist.",
        "positive": "Lattice simulations with G-parity Boundary Conditions: We discuss G-parity lattice boundary conditions as a means to impose momentum\non the pion ground state without breaking isospin symmetry. This technique is\nexpected to be critical for the precision measurement of\n$K\\rightarrow(\\pi\\pi)_{I=0}$ matrix elements where physical kinematics demands\nmoving pions in the final state and the statistical noise caused by\ndisconnected contributions will make it difficult to use multi-exponential fits\nto isolate this as an excited state. We present a formalism for computing\nhadronic Green's functions with G-parity boundary conditions, derive the\ndiscretized action and its symmetries, discuss how the strange quark can be\nintroduced and detail techniques for the numerical implementation of these\nboundary conditions. We demonstrate and test these methods using several\n$16^3\\times 32$ dynamical domain wall ensembles with a $420$ MeV pion mass and\nG-parity boundary conditions in one and two spatial directions."
    },
    {
        "anchor": "Spectroscopy of triply-charmed baryons from lattice QCD: The spectrum of excitations of triply-charmed baryons is computed using\nlattice QCD including dynamical light quark fields. Calculations are performed\non anisotropic lattices with temporal and spatial spacings a_t = 0.0351(2) and\na_s ~ 0.12 fm respectively and with pion mass of about 390 MeV. The spectrum\nobtained has baryonic states with well-defined total spin up to 7/2 and the\nlow-lying states closely resemble the expectation from models with an SU(6)X\nO(3) symmetry. Energy splittings between extracted states, including those due\nto spin-orbit coupling in the heavy quark limit are computed and compared\nagainst data at other quark masses.",
        "positive": "Expectation values of Coherent States for ${\\rm SU}(2)$ Lattice Gauge\n  Theories: This article investigates properties of semiclassical Gauge Field Theory\nCoherent States for general quantum gauge theories. Useful, e.g., for the\ncanonical formulation of Lattice Gauge Theories these states are labelled by a\npoint in the classical phase space and constructed such that the expectation\nvalues of the canonical operators are sharply peaked on said phase space point.\nFor the case of the non-abelian gauge group SU(2), we will explicitly compute\nthe expectation value of general polynomials including the first order quantum\ncorrections. This allows asking more precise questions about the quantum\nfluctuations of any given semiclassical system."
    },
    {
        "anchor": "Meson mass spectrum at finite temperature and density in the strong\n  coupling limit of lattice QCD for color SU(3): We investigate the meson mass spectrum in the strong coupling limit of\nlattice QCD with one species of staggered fermion for the SU(N_c) color gauge\ngroup, including N_c=3. We analytically derive meson masses as functions of\ntemperature and chemical potential via chiral condensates. We show that meson\nmasses quickly decrease to zero when the chemical potential or the temperature\napproaches to the critical value.",
        "positive": "Unpolarized isovector quark distribution function from Lattice QCD: A\n  systematic analysis of renormalization and matching: We present a detailed Lattice QCD study of the unpolarized isovector quark\nParton Distribution Function (PDF) using large-momentum effective theory\nframework. We choose a quasi-PDF defined by a spatial correlator which is free\nfrom mixing with other operators of the same dimension. In the lattice\nsimulation, we use a Gaussian-momentum-smeared source at $M_\\pi=356$ MeV and\n$P_z \\in \\{1.8,2.3\\}$ GeV. To control the systematics associated with the\nexcited states, we explore {five different source-sink separations}. The\nnonperturbative renormalization is conducted in a regularization-independent\nmomentum subtraction scheme, and the matching between the renormalized\nquasi-PDF and $\\bar{\\rm MS}$ PDF is calculated based on perturbative QCD up to\none-loop order. Systematic errors due to renormalization and perturbative\nmatching are also analyzed in detail. Our results for lightcone PDF are in\nreasonable agreement with the latest phenomenological analysis."
    },
    {
        "anchor": "MDP_QCD: Object Oriented Programming for Lattice Gauge Theory: This is a manual (built by examples) to explain the use of MDP_QCD. It\nconsists of an ensemble of classes and functions (written in GNU C++) to help\nin writing programs for lattice QCD in a particularly Object Oriented fashion.\nSome tricks are implemented to optimize speed and reduce memory usage on PCs,\nworkstations and parallel computers with sheared memory. The basic classes are:\nMatrix, gauge_field, fermi_field and stochastic light_propagators (the code\nworks for any SU(N) gauge group).",
        "positive": "A strong-coupling analysis of two-dimensional O(N) sigma models with\n  $N\\geq 3$ on square, triangular and honeycomb lattices: Recently-generated long strong-coupling series for the two-point Green's\nfunctions of asymptotically free ${\\rm O}(N)$ lattice $\\sigma$ models are\nanalyzed, focusing on the evaluation of dimensionless renormalization-group\ninvariant ratios of physical quantities and applying resummation techniques to\nseries in the inverse temperature $\\beta$ and in the energy $E$. Square,\ntriangular, and honeycomb lattices are considered, as a test of universality\nand in order to estimate systematic errors. Large-$N$ solutions are carefully\nstudied in order to establish benchmarks for series coefficients and\nresummations. Scaling and universality are verified. All invariant ratios\nrelated to the large-distance properties of the two-point functions vary\nmonotonically with $N$, departing from their large-$N$ values only by a few per\nmille even down to $N=3$."
    },
    {
        "anchor": "From ten-flavor tests of the $\u03b2$-function to $\u03b1_s$ at the\n  Z-pole: New tests are applied to two $\\beta$-functions of the much-discussed BSM\nmodel with ten massless fermion flavors in the fundamental representation of\nthe SU(3) color gauge group. The renormalization scheme of the two\n$\\beta$-functions is defined on the gauge field gradient flow in respective\nfinite or infinite physical volumes at zero lattice spacing. Recently published\nresults in the ten-flavor theory led to indicators of an infrared fixed point\n(IRFP) in the finite-volume step $\\beta$-function in the strong coupling regime\nof the theory arXiv:2004.00754. We analyze our substantially extended set of\nten-flavor lattice ensembles at strong renormalized gauge couplings and find no\nevidence or hint for IRFP in the finite-volume step $\\beta$-function within\ncontrolled lattice reach. We also discuss new ten-flavor tests of the recently\nintroduced lattice definition and algorithmic implementation of the\n$\\beta$-function defined on the gradient flow of the gauge field over infinite\nEuclidean space-time in the continuum. Originally we introduced this new\nalgorithm to match finite-volume step $\\beta$-functions in massless\nnear-conformal gauge theories with the infinite-volume $\\beta$-function reached\nin the chiral limit from small fermion mass deformations of spontaneous chiral\nsymmetry breaking.\n  Results from the lattice analysis of the ten-flavor infinite-volume\n$\\beta$-function are consistent with the absence of IRFP from our step\n$\\beta$-function based analysis. We make important contact at weak coupling in\ninfinite volume with gradient flow based three-loop perturbation theory,\nserving as a first pilot study toward the long-term goal of developing\nalternate approach to the determination of the strong coupling $\\alpha_s$ at\nthe Z-boson pole in QCD.",
        "positive": "Instability in the Molecular Dynamics Step of Hybrid Monte Carlo in\n  Dynamical Fermion Lattice QCD Simulations: We investigate instability and reversibility within Hybrid Monte Carlo\nsimulations using a non-perturbatively improved Wilson action. We demonstrate\nthe onset of instability as tolerance parameters and molecular dynamics step\nsizes are varied. We compare these findings with theoretical expectations and\npresent limits on simulation parameters within which a stable and reversible\nalgorithm is obtained for physically relevant simulations. Results of\noptimisation experiments with respect to tolerance prarameters are also\npresented."
    },
    {
        "anchor": "The MultiBoson method: This review describes the multiboson algorithm for Monte Carlo simulations of\nlattice QCD, including its static and dynamical aspects, and presents a\ncomparison with Hybrid Monte Carlo.",
        "positive": "Lorentz gauge fixing and the Gribov problem: the fermion correlator in\n  lattice compact QED with Wilson fermions: For the Lorentz gauge the influence of Gribov copies on the fermion\npropagator is investigated in quenched lattice compact QED. In the Coulomb\nphase zero-momentum modes of the gauge fields are shown to be the main reason\nfor a significant deviation from ordinary perturbation theory."
    },
    {
        "anchor": "Comments on k-Strings at Large N: We present a computation of the k-string tension in the large N limit of the\ntwo dimensional lattice Yang-Mills theory. It is well known that the problems\nof computing the partition function and the Wilson loop can be both reduced to\na unitary matrix integral which has a third order phase transition separating\nweak and strong coupling. We give an explicit computation of the interaction\nenergy for k-strings in the large N limit when k/N is held constant and\nnon-zero. In this limit, the interaction energy is finite and attractive. We\nshow that, in the strong coupling phase, the k -> N - k duality is realized as\na first order phase transition. We also show that the lattice k-string tension\nreduces to the expected Casimir scaling in the continuum limit.",
        "positive": "Light hadron spectroscopy in quenched QCD with overlap fermions: A simulation of quenched QCD with the overlap Dirac operator has been carried\nout using 100 Wilson gauge configurations at beta = 6 on an 18^3 x 64 lattice\nand at beta = 5.85 on a 14^3 x 48 lattice. Here we present results for meson\nmasses, meson final state \"wave functions,\" decay constants, and other\nobservables, as well as details on our algorithmic and data analysis\ntechniques. We also summarize results for baryon masses and quark and diquark\npropagators in the Landau gauge."
    },
    {
        "anchor": "The masses of the mesons and baryons. Part III. The size of the\n  particles: The size of the stable elementary particles is investigated with the standing\nwave model. The particle size follows from the magnitude of the radiation\npressure. It is shown that the outward directed radiation pressure is balanced\nby the inward directed elastic force per unit area in the cubic nuclear\nlattice, provided that the sidelength of the lattice is 10^(-13) cm, which\nagrees with the measured radius of the proton r = 0.8 \\times 10^(-13) cm,\nwithin the uncertainty of the parameters.",
        "positive": "Peculiarities in the Spectrum of the Adjoint Scalar Kinetic Operator in\n  Yang-Mills Theory: We study the spectrum of low-lying eigenmodes of the kinetic operator for\nscalar particles, in the color adjoint representation of Yang-Mills theory. The\nkinetic operator is the covariant Laplacian, plus a constant which serves to\nrenormalize mass. In the pure gauge theory, our data indicates that the\ninterval between the lowest eigenvalue and the mobility edge tends to infinity\nin the continuum limit. On these grounds, it is suggested that the perturbative\nexpression for the scalar propagator may be misleading even at distance scales\nthat are small compared to the confinement scale. We also measure the density\nof low-lying eigenmodes, and find a possible connection to multi-critical\nmatrix models of order m=1."
    },
    {
        "anchor": "Lattice Supersymmetry and Holography: Over the last twenty years, work based on lattice supersymmetry has generated\nmany new results and insights into the non-perturbative nature of string\ntheory, quantum black holes, and gravity. This endeavor is a broad research\nprogram encompassing lattice field theory, supersymmetry, string theory, and\nquantum gravity. In this volume, we look at a selected subset of the topics\ncovering recent progress in lattice supersymmetry and holography.",
        "positive": "Random Walk Model on a Hyper-Spherical Lattice: We use a one-dimensional random walk on $D$-dimensional hyper-spheres to\ndetermine the critical behavior of statistical systems in hyper-spherical\ngeometries. First, we demonstrate the properties of such walk by studying the\nphase diagram of a percolation problem. We find a line of second and first\norder phase transitions separated by a tricritical point. Then, we analyze the\nadsorption-desorption transition for a polymer growing near the attractive\nboundary of a cylindrical cell membrane. We find that the fraction of adsorbed\nmonomers on the boundary vanishes exponentially when the adsorption energy\ndecreases towards its critical value. We observe a crossover phenomenon to an\narea of linear growth at energies of the order of the inverse cell radius."
    },
    {
        "anchor": "Phenomenology from 100 large lattices: We present a status report on simulations being done on $32^3 \\times 64$\nlattices at $\\beta = 6.0$ using quenched Wilson fermions. Phenomenologically\nrelevant results for the spectrum, decay constants, the kaon B-parameter $B_K$,\n$B_7$, $B_8$, semi-leptonic and $B\\to K^* \\gamma$ form factors are given based\non a statistical sample of 100 configurations.",
        "positive": "Chiral logs in twisted mass lattice QCD with large isospin breaking: The pion masses and the pion decay constant are calculated to 1-loop order in\ntwisted mass Wilson chiral perturbation theory, assuming a large pion mass\nsplitting and tuning to maximal twist. Taking the large mass splitting at\nleading order in the chiral expansion leads to significant modifications in the\nchiral logarithms. For example, the result for the charged pion mass contains a\nchiral logarithm that involves the neutral pion mass instead of the charged\none. Similar modifications appear in the results for the neutral pion mass and\nthe decay constant. These new results are used in fits to lattice data obtained\nrecently by the European twisted mass collaboration. The data can be fitted\nwell, in general better than with the standard chiral perturbation theory\nexpressions that ignore the mass splitting. The impact on the extraction of\nlow-energy couplings is briefly discussed."
    },
    {
        "anchor": "4d Simplicial Quantum Gravity Interacting with Gauge Matter Fields: The effect of coupling non-compact $U(1)$ gauge fields to four dimensional\nsimplicial quantum gravity is studied using strong coupling expansions and\nMonte Carlo simulations. For one gauge field the back-reaction of the matter on\nthe geometry is weak. This changes, however, as more matter fields are\nintroduced. For more than two gauge fields the degeneracy of random manifolds\ninto branched polymers does not occur, and the branched polymer phase seems to\nbe replaced by a new phase with a negative string susceptibility exponent\n$\\gamma$ and fractal dimension $d_H \\approx 4$.",
        "positive": "Staggered Dslash Performance on Intel Xeon Phi Architecture: The conjugate gradient (CG) algorithm is among the most essential and time\nconsuming parts of lattice calculations with staggered quarks. We test the\nperformance of CG and dslash, the key step in the CG algorithm, on the Intel\nXeon Phi, also known as the Many Integrated Core (MIC) architecture. We try\ndifferent parallelization strategies using MPI, OpenMP, and the vector\nprocessing units (VPUs)."
    },
    {
        "anchor": "Dual lattice representations for O(N) and CP(N-1) models with a chemical\n  potential: We derive dual representations for O(N) and CP(N-1) models on the lattice. In\nterms of the dual variables the partition sums have only real and positive\ncontributions also at finite chemical potential. Thus the complex action\nproblem of the conventional formulation is overcome and using the dual\nvariables Monte Carlo simulations are possible at arbitrary chemical potential.",
        "positive": "Nucleon structure from 2+1-flavor domain-wall QCD: Nucleon-structure calculations of isovector vector- and axialvector-current\nform factors, transversity and scalar charge, and quark momentum and helicity\nfractions are reported from two recent 2+1-flavor dynamical domain-wall\nfermions lattice-QCD ensembles generated jointly by the RIKEN-BNL-Columbia and\nUKQCD Collaborations with Iwasaki $\\times$\ndislocation-suppressing-determinatn-ratio gauge action at inverse lattice\nspacing of 1.378(7) GeV and pion mass values of 249.4(3) and 172.3(3) MeV."
    },
    {
        "anchor": "The \"hard\" problem of strong of interactions: This is a write-up of a lecture at the level of a physics colloquium. There\nexists an idealized mathematical formulation of strong interactions which has\nno free parameters but is known to describe the real world quite accurately.\nOver the last three decades the problem has been managed with increasing\nsuccess. An overview of some facts and a little fiction will be presented, but\nthe question whether the problem can now be considered \"easy\" will be left\nunanswered.",
        "positive": "Excited hadrons in n_f=2 QCD: The chirally improved (CI) fermion action allows us to obtain results for\npion masses down to 320 MeV on (in lattice units) comparatively small lattices\nwith physical extent of 2.4 fm. We use differently smeared quarks sources to\nbuild sets of several interpolators. The variational method then leads to\nexcellent ground state masses for most mesons and baryons. The excited state\nsignals weaken in quality towards smaller quark masses. In particular the\nexcited baryons come out too high."
    },
    {
        "anchor": "The Dirac operator spectrum: a perturbative approach: By computing the Dirac operator spectrum by means of Numerical Stochastic\nPerturbation Theory, we aim at throwing some light on the widely accepted\npicture for the mechanism which is behind the Bank-Casher relation. The latter\nrelates the chiral condensate to an accumulation of eigenvalues in the low end\nof the spectrum. This can be in turn ascribed to the usual mechanism of\nrepulsion among eigenvalues which is typical of quantum interactions. First\nresults appear to confirm that NSPT can indeed enable us to inspect a huge\nreshuffling of eigenvalues due to quantum repulsion.",
        "positive": "Coarse graining in effective theories of lattice QCD in 1+1d and 2+1d: In the strong coupling and heavy quark mass regime, lattice QCD dimensionally\nreduces to effective theories of Polyakov loops depending on the parameters of\nthe original Wilson action $\\beta, \\kappa$ and $N_\\tau$. We apply coarse\ngraining techniques to such theories in 1d and 2d, corresponding to lattice QCD\nat finite temperature and non-zero chemical potential in 1+1d and 2+1d,\nrespectively. In 1d the method is applied to the effective theories up to\n$\\mathcal{O}(\\kappa^4)$. Using the transfer matrix, the recursion relations are\nsolved analytically. The thermodynamic limit is taken for some observables.\nAfterwards, continuum extrapolation is performed numerically and results are\ndiscussed. In 2d the coarse graining method is applied in the pure gauge and\nstatic quark limit. Running couplings are obtained and the fixed points of the\ntransformations are discussed. Finally, the critical coupling of the\ndeconfinement transition is determined in both limits. Agreement to about 12%\nwith Monte Carlo results of 2+1d Yang-Mills theory from the literature is\nobserved."
    },
    {
        "anchor": "Properties of canonical fermion determinants with a fixed quark number: Using a dimensional reduction formula for the lattice fermion determinant we\nstudy canonical determinants on quenched SU(3) gauge configurations. The\ncanonical determinants decribe a fixed quark number and we analyze their\nproperties below and above the transition temperature. We find that above $T_c$\nthe signatures of center symmetry breaking are very strongly manifest in the\ndistribution of the canonical determinants in the complex plane, and we discuss\npossible physical implications of this finding. We furthermore analyze the\nrelative weight of the different quark sectors below and above the transition\ntemperature.",
        "positive": "Recent progress of lattice and non-lattice super Yang-Mills: We report recent progress of non-perturbative formulation of supersymmetric\nYang-Mills. Although lattice formulations of two-dimensional theories which are\nfine tuning free to all order in perturbation theory are known for almost ten\nyears, however, there were only few evidence for the validity at\nnon-perturbative level. In this talk we argue that most numerical studies so\nfar do not capture the physics in continuum, and add new evidence that lattice\nformulation works at non-perturbatively. We further point out that, by\ncombining two-dimensional lattice and matrix model techniques inspired by\nD-brane dynamics in superstring theory, a non-perturbative formulation of the\nfour-dimensional maximally supersymmetric Yang-Mills theory, which is free from\nthe fine tuning at least to all order in perturbation theory, is obtained."
    },
    {
        "anchor": "S wave bottomonium states moving in a quark-gluon plasma from lattice\n  NRQCD: We extend our study of bottomonium spectral functions in the quark-gluon\nplasma to nonzero momentum. We use lattice QCD simulations with two flavours of\nlight quark on highly anisotropic lattices and treat the bottom quark with\nnonrelativistic QCD (NRQCD). We focus on S wave (Upsilon and eta_b) channels\nand consider nonrelativistic velocities, v/c < 0.2. A comparison with\npredictions from effective field theory is made.",
        "positive": "Hadronic vacuum polarization contribution to the muon $g-2$ with 2+1\n  flavor lattice QCD on a larger than (10 fm$)^4$ lattice at the physical point: We study systematic uncertainties in the lattice QCD computation of hadronic\nvacuum polarization (HVP) contribution to the muon $g-2$. We investigate three\nsystematic effects; finite volume (FV) effect, cutoff effect, and integration\nscheme dependence. We evaluate the FV effect at the physical pion mass on two\ndifferent volumes of (5.4 fm$)^4$ and (10.8 fm$)^4$ using the PACS10\nconfigurations at the same cutoff scale. For the cutoff effect, we compare two\ntypes of lattice vector operators, which are local and conserved\n(point-splitting) currents, by varying the cutoff scale on a larger than (10\nfm$)^4$ lattice at the physical point. For the integration scheme dependence,\nwe compare the results between the coordinate- and momentum-space integration\nschemes at the physical point on a (10.8 fm$)^4$ lattice. Our result for the\nHVP contribution to the muon $g-2$ is given by $a_\\mu^{\\rm hvp} =\n737(9)(^{+13}_{-18})\\times 10^{-10}$ in the continuum limit, where the first\nerror is statistical and the second one is systematic."
    },
    {
        "anchor": "Calculation of the decay width of decuplet baryons: We calculate the coupling constant and decay width of the decuplet to octet\nbaryon transitions in lattice QCD using the transfer matrix method. The\ntransition amplitude is related to the coupling constant and via the Fermi's\nGolden Rule to the decay width. The method is applicable for near-degeneracy of\nthe energy levels of initial and final states and, when this condition is\nfulfilled, yields a good estimate of the decay width. We present results using\na hybrid action with domain wall valence quarks on a staggered sea with $350$\nMeV pion mass as well as for a domain wall fermion action with $180$ MeV pion\nmass. We find $\\Gamma\\left( \\Delta \\to \\pi\\,N \\right) = 119\\,( 8)\\,( 8)$ MeV\nfor the transition of Delta to pion-nucleon within the unitary domain wall\nsetup. We also report values for the decay widths of the $\\Sigma^*$ and $\\Xi*$\nbaryons.",
        "positive": "Heavy quark potential in lattice QCD at finite temperature: Results of the study of lattice QCD with two flavors of nonperturbatively\nimproved Wilson fermions at finite temperature are presented. The transition\ntemperature for m_{\\pi}/m_{\\rho} \\sim 0.8 and lattice spacing a \\sim 0.12 fm is\ndetermined. A two-exponent ansatz is successfully applied to describe the heavy\nquark potential in the confinement phase."
    },
    {
        "anchor": "Fisher's zeros, complex RG flows and confinement in LGT models: The zeros of the partition function in the complex beta plane (Fisher's\nzeros) play an important role in our understanding of phase transitions and RG\nflows. Recently, we argued that they act as gates or separatrices for complex\nRG flows. Using histogram reweighting to construct the density of states, we\ncalculate the Fisher's zeros for pure gauge SU(2) and U(1) on L^4 lattices. For\nSU(2), these zeros appear to move almost horizontally when the volume\nincreases. They stay away from the real axis which indicates a confining theory\nat zero temperature. We discuss the effect of an adjoint term on these results.\nIn contrast, using recent multicanonical simulations for the U(1) model for L\nup to 8 we find that the zeros pinch the real axis near beta =1.0113.\nPreliminary results concerning U(1) at larger volumes, SU(3) with 3 light\nflavors and plans to delimit the boundary of the conformal window are briefly\ndiscussed.",
        "positive": "The gradient flow of the Dirac spectrum: We construct chiral perturbation theory for the gradient flow of the\nmicroscopic Dirac eigenvalues and compute the density of and correlations\nbetween the microscopic eigenvalues at zero and non-zero flow time. The results\nshow that the repulsion of the microscopic Dirac eigenvalues from the dynamical\nquark mass decreases with increasing gradient flow time. Furthermore, the flow\nof the spectral resolvent is compared to the flow of the chiral condensate\nobtained from a fermionic gradient flow."
    },
    {
        "anchor": "A Simulation of the 't Hooft Model at finite N_c with the Overlap Dirac\n  Operator: We present some results of a numerical investigation of the 't Hooft model\nwith 2,3 and 4 colors, regularized on the lattice with overlap fermions.",
        "positive": "Four - Fermi Theories in Fewer Than Four Dimensions: Four-fermi models in dimensionality $2<d<4$ exhibit an ultra-violet stable\nrenormalization group fixed point at a strong value of the coupling constant\nwhere chiral symmetry is spontaneously broken. The resulting field theory\ndescribes relativistic fermions interacting non-trivially via exchange of\nscalar bound states. We calculate the $O(1/N_f)$ corrections to this picture,\nwhere $N_f$ is the number of fermion species, for a variety of models and\nconfirm their renormalizability to this order. A connection between\nrenormalizability and the hyperscaling relations between the theory's critical\nexponents is made explicit. We present results of extensive numerical\nsimulations of the simplest model for $d=3$, performed using the hybrid Monte\nCarlo algorithm on lattice sizes ranging from $8^3$ to $24^3$. For $N_f=12$\nspecies of massless fermions we confirm the existence of a second order phase\ntransition where chiral symmetry is spontaneously broken. Using both direct\nmeasurement and finite size scaling arguments we estimate the critical\nexponents $\\beta$, $\\gamma$, $\\nu$ and $\\delta$. We also investigate symmetry\nrestoration at non-zero temperature, and the scalar two-point correlation\nfunction in the vicinity of the bulk transition. All our results are in\nexcellent agreement with analytic predictions, and support the contention that\nthe $1/N_f$ expansion is accurate for this class of models."
    },
    {
        "anchor": "New algorithm for classical gauge theory simulations in an expanding box: We propose a new algorithm for classical statistical simulations in scalar\nand gauge theories undergoing a one dimensional expansion, which allows\nsimulations to study boxes of larger transverse extent and to continue for\nlonger times, without losing lattice resolution in the expanding direction.",
        "positive": "Strongly Coupled QED: A short review of some of the most relevant contributions to non-perturbative\nQED is done. Since a Gaussian behaviour of QED \\`a la $\\lambda\\phi^4$ has been\nruled out by the numerical data, I analyse the other two most reliable\nscenarios, i.e. triviality \\`a la Nambu-Jona Lasinio and non-Gaussian critical\nbehaviour. I give a suggestive theoretical argument against a Gaussian\nbehaviour of QED \\`a la Nambu-Jona Lasinio, and show how the numerical data for\nthe susceptibility at the critical point of QED support this result."
    },
    {
        "anchor": "Proposal for the numerical solution of planar QCD: Using quenched reduction, we propose a method for the numerical calculation\nof meson correlation functions in the planar limit of QCD. General features of\nthe approach are outlined, and an example is given in the context of\ntwo-dimensional QCD.",
        "positive": "The Mass Ratio Between Neutrinos and Charged Leptons: In the framework of the recently proposed electroweak theory on a Planck\nlattice, we are able to solve approximately the lattice Dyson equation for the\nfermion self-energy functions and show that the large difference of charged\nlepton and neutrino masses is caused by their very different gauge couplings.\nThe predicted mass ratio ($10^{-5}\\sim 10^{-6}$) between neutrinos and charged\nlepton is compatible with present experiments."
    },
    {
        "anchor": "Bounds on the renormalized couplings in an SU(2)_L \\otimes SU(2)_R\n  symmetric Yukawa model: The vacuum stability lower bound on the mass of the Higgs boson is\nnumerically investigated in an $SU(2)_L \\otimes SU(2)_R$ symmetric Yukawa\nmodel, which describes two heavy degenerate fermion doublets in the limit of\nvanishing gauge couplings. Good agreement with perturbation theory is found,\nalthough the couplings are strong. The upper bound on the fermion mass and\nrenormalized Yukawa coupling is also determined in the part of bare parameter\nspace where reflection positivity has been proven.",
        "positive": "Casimir effect in Yang-Mills theory: We study, for the first time, the Casimir effect in non-Abelian gauge theory\nusing first-principle numerical simulations. Working in two spatial dimensions\nat zero temperature we find that closely spaced perfect chromoelectric\nconductors attract each other with a small anomalous scaling dimension. At\nlarge separation between the conductors, the attraction is exponentially\nsuppressed by a new massive quantity, the Casimir mass, which is surprisingly\ndifferent from the lowest glueball mass. The apparent emergence of the new\nmassive scale may be a result of the backreaction of the vacuum to the presence\nof the plates as sufficiently close chromoelectric conductors induce, in a\nspace between them, a smooth crossover transition to a color deconfinement\nphase."
    },
    {
        "anchor": "Precision study of B^* B\u03c0coupling for the static heavy-light meson: We compute the B^*B\\pi coupling \\hat{g}_{\\infty} for static heavy-light meson\nusing all-to-all propagators. It is shown that low-mode averaging with 100\nlow-lying eigenmodes indeed improves the signal for the 2-point and 3-point\nfunctions for heavy-light meson significantly. Our study suggests that the\nall-to-all propagator will be a very efficient method for high precision\ncomputation of the B^*B\\pi coupling especially in unquenched QCD where the\nnumber of configurations is limited.",
        "positive": "A Stochastic Method for Semileptonic Form Factor Calculations on the\n  Lattice: We investigate an alternative to the Sequential Propagator Method used in\nLattice QCD calculations of semileptonic form factors. We replace the\nsequential propagator with a stochastic propagator so that, in principle, all\nmomentum and sink smearing combinations are available with only a single\nspin-color inversion. Practically, the stochastic noise is significant and must\nbe reduced at the cost of more inversions. We study the behavior of the\nstochastic noise and compare the computational costs of this stochastic\ntechnique and the Sequential Propagator Method. We also present preliminary\nsemileptonic form factor results using the stochastic technique on N_f=2\nconfigurations with a non-perturbatively improved Sheikoleslami-Wohlert action\ngenerated by the QCDSF collaboration. At a fixed cost, measured in terms of the\nnumber of heavy-quark inversions, the method provides more correlators for the\nextraction of the form factors at various q^2's than the Sequential Propagator\nMethod. These additional correlators reduce the total statistical errors of\ncertain kinematic points, although the stochastic error is still comparable to\nthe gauge error at other points."
    },
    {
        "anchor": "Percolation and Magnetization for Generalized Continuous Spin Models: For the Ising model, the spin magnetization transition is equivalent to the\npercolation transition of Fortuin-Kasteleyn clusters; this result remains valid\nalso for the conventional continuous spin Ising model. The investigation of\nmore general continuous spin models may help to obtain a percolation\nformulation for the critical behaviour in SU(2) gauge theory. We therefore\nstudy a broad class of theories, introducing spin distribution functions,\nlonger range interactions and self-interaction terms. The thermal behaviour of\neach model turns out to be in the Ising universality class. The corresponding\npercolation formulations are then obtained by extending the Fortuin-Kasteleyn\ncluster definition; in several cases they illustrate recent rigorous results.",
        "positive": "Center vortex model for the infrared sector of Yang-Mills theory -\n  Confinement and Deconfinement: A model for the infrared sector of Yang-Mills theory based on magnetic\nvortices represented by (closed) random surfaces is investigated using lattice\nMonte Carlo methods. The random surfaces are governed by a surface area action\nand a curvature action. The model generates a finite-temperature deconfinement\ntransition; the coupling constants of the model can be chosen such as to\nreproduce the SU(2) Yang-Mills ratio of the deconfinement temperature to the\nsquare root of the zero-temperature string tension, T_c / sqrt{sigma_0} =0.69.\nThis yields a physical trajectory in the space of coupling constants on which\nthe confinement properties are approximately invariant. An at first sight\nsurprisingly accurate prediction of the spatial string tension in the\ndeconfined phase results, which can be made plausible in view of the specific\nspace-time structure of the vortex configurations in this phase. The\nconfinement properties are shown to be intimately tied to the percolation\nproperties of the vortex surfaces."
    },
    {
        "anchor": "Nucleon in a periodic magnetic field: The energy shift of a nucleon in a static periodic magnetic field is\nevaluated at second order in the external field strength in perturbation\ntheory. It is shown that the measurement of this energy shift on the lattice\nallows one to determine the unknown subtraction function in the forward doubly\nvirtual Compton scattering amplitude. The limits of applicability of the\nobtained formula for the energy shift are discussed.",
        "positive": "Spectrum of the Hermitian Wilson-Dirac Operator for a Uniform Magnetic\n  Field in Two Dimensions: It is shown that the eigenvalue problem for the hermitian Wilson-Dirac\noperator of for a uniform magnetic field in two dimensions can be reduced to\none-dimensional problem described by a relativistic analog of the Harper\nequation. An explicit formula for the secular equations is given in term of a\nset of polynomials. The spectrum exhibits a fractal structure in the infinite\nvolume limit. An exact result concerning the index theorem for the overlap\nDirac operator is obtained."
    },
    {
        "anchor": "High temperature QCD with three flavors of improved staggered quarks: We present an update of our study of high temperature QCD with three flavors\nof quarks, using a Symanzik improved gauge action and the Asqtad staggered\nquark action. Simulations are being carried out on lattices with Nt=4, 6 and 8\nfor the case of three degenerate quarks with masses less than or equal to the\nstrange quark mass, $m_s$, and on lattices with Nt=6 and 8 for degenerate up\nand down quarks with masses in the range 0.2 m_s \\leq m_{u,d} \\leq 0.6 m_s, and\nthe strange quark fixed near its physical value. We also report on first\ncomputations of quark number susceptibilities with the Asqtad action. These\nsusceptibilities are of interest because they can be related to event-by-event\nfluctuations in heavy ion collision experiments. Use of the improved quark\naction leads to a substantial reduction in lattice artifacts. This can be seen\nalready for free fermions and carries over into our results for QCD.",
        "positive": "Quenched Light Hadron Spectrum and Decay Constants using Improved Wilson\n  Fermion Actions: We compare results obtained using the Sheikholeslami-Wohlert (SW) fermion\naction with tree-level and tadpole-improved coefficients for $5.7\\le\\beta\\le\n6.2$."
    },
    {
        "anchor": "Density of states techniques for fermion worldlines: Worldline representations were established as a powerful tool for studying\nbosonic lattice field theories at finite density. For fermions, however, the\nworldlines still may carry signs that originate from the Dirac algebra and from\nthe Grassmann nature of the fermion fields. We show that a density of states\napproach can be set up to deal with this remaining sign problem, where finite\ndensity is implemented in a canonical approach by working with a fixed winding\nnumber of the fermion worldlines. We discuss the approach in detail and show\nfirst results of a numerical implementation in 2 dimensions.",
        "positive": "The omega-rho meson mass splitting and mixing from lattice QCD: We compare flavour singlet and non-singlet vector mesons from first\nprinciples using lattice QCD. With N_f=2 flavours of light quark, this\naddresses the omega-rho mass difference.\n  Using maximally twisted-mass lattice QCD, we are able for the first time to\ndetermine this mass difference precisely and we compare with experiment. We\nalso discuss omega-rho mixing effects arising within QCD through the u-d quark\nmass difference."
    },
    {
        "anchor": "Species Doublers as Super Multiplets in Lattice Supersymmetry: Chiral\n  Conditions of Wess-Zumino Model for D=N=2: We propose an algebraic lattice supersymmetry formulation which has an exact\nsupersymmetry on the lattice. We show how lattice version of chiral conditions\ncan be imposed to satisfy an exact lattice supersymmetry algebra. The species\ndoublers of chiral fermions and the corresponding bosonic counterparts can be\naccommodated to fit into chiral supermultiplets of lattice supersymmetry and\nthus lattice chiral fermion problem does not appear. We explicitly show how N=2\nWess-Zumino model in one and two dimensions can be formulated to keep exact\nsupersymmetry for all super charges on the lattice. The momentum representation\nof N=2 lattice chiral sypersymmetry algebra has lattice periodicity and thus\nmomentum conservation should be modified to a lattice version of sine momentum\nconservation, which generates nonlocal interactions and leads to a loss of\nlattice translational invariance. It is shown that the nonlocality is mild and\nthe translational invariance is recovered in the continuum limit. In the\ncoordinate representation a new type of product is defined and the difference\noperator satisfies Leibnitz rule and an exact lattice supersymmetry is realized\non this product.",
        "positive": "Blocking-inspired supersymmetric actions: a status report: We provide a status report on the advances in blocking-inspired\nsupersymmetric actions. This is done at the example of interacting\nsupersymmetric quantum mechanics as well as the Wess-Zumino model. We\ninvestigate in particular the implications of a nontrivial realisation of\ntranslational symmetry on the lattice in this approach. We also discuss the\nlocality of symmetry generators."
    },
    {
        "anchor": "Upper bound on the cutoff in the Standard Model: The main objective of this presentation is to point out that the Upper bound\non the cutoff in lattice Electroweak theory is still unknown. The consideration\nof the continuum theory is based on the perturbation expansion around trivial\nvacuum. The internal structure of the lattice Weinberg - Salam model may appear\nto be more complicated especially in the region of the phase diagram close to\nthe phase transition between the physical Higgs phase and the unphysical\nsymmetric phase of the lattice model, where the continuum physics is to be\napproached. We represent the results of our numerical investigation of the\nquenched model at infinite bare scalar self coupling $\\lambda$. These results\ndemonstrate that at $\\lambda = \\infty$ the upper bound on the cutoff is around\n$\\frac{\\pi}{a} = 1.4$ Tev. The preliminary results for finite $\\lambda$ are\nalso presented. Basing on these results we cannot yet make a definite\nconclusion on the maximal value of the cutoff admitted in the lattice model,\nalthough we have found that the cutoff cannot exceed the value around $1.4 \\pm\n0.2$ Tev for a certain particular choice of the couplings ($\\lambda = 0.009$,\n$\\beta = 12$, $\\theta_W = 30^o$) for the lattices of sizes up to\n$12^3\\times16$. We also observe that the topological defects, which are to be\nidentified with quantum Nambu monopoles, dominate in vacuum in the vicinity of\nthe transition. This indicates that the vacuum of the model is different from\nthe trivial one. In addition we remind the results of the previous numerical\ninvestigations of the SU(2) gauge - Higgs model, where the maximal reported\nvalue of the cutoff was around 1.5 Tev.",
        "positive": "Two Poisson structures invariant with respect to discrete transformation\n  in the case of arbitrary semi-simple algebras: Two Poisson structures invariant with respect to discrete transformation of\nthe Maximal root in the case of arbitrary semi-simple algebras are presented in\nexplicit form. Thus the problem of construction of equations of n-wave\nhierarchy in the case of arbitrary semi simple algebra is solved finally."
    },
    {
        "anchor": "The Worldsheet Formulation as an Alternative Method for Simulating\n  Dynamical Fermions: The recently proposed worldsheet formulation of lattice fermions is tested\nfor the first time carrying out a simulation for the simplest model: the\none-flavor, strictly massless lattice Schwinger model. A main advantage of this\nalternative method for simulating dynamical fermions consists in its economy:\nit involves many fewer degrees of freedom than the ordinary Kogut-Susskind\nformulation. The known continuum limit is reproduced by the method for\nrelatively small lattices.",
        "positive": "Monopole clusters and critical dynamics in four-dimensional U(1): We investigate monopoles in four-dimensional compact U(1) with Wilson action.\nWe focus our attention on monopole clusters as they can be identified\nunambiguously contrary to monopole loops. We locate the clusters and determine\ntheir properties near the U(1) phase transition. The Coulomb phase is\ncharacterized by several small clusters, whereas in the confined phase the\nsmall clusters coalesce to one large cluster filling up the whole system. We\nfind that clusters winding around the periodic lattice are absent within both\nphases and during the transition. However, within the confined phase, we\nobserve periodically closed monopole loops if cooling is applied."
    },
    {
        "anchor": "The quark propagator in momentum space: The quark propagator is calculated in the Landau gauge at beta=6.0. A method\nfor removing the dominant, tree-level lattice artefacts is presented, enabling\na calculation of the momentum-dependent dynamical quark mass.",
        "positive": "Dynamical-parameter algorithm for U(1) gauge theory: We present an algorithm for Monte Carlo simulations which is able to overcome\nthe suppression of transitions between the phases in compact U(1) lattice gauge\ntheory in 4 dimensions."
    },
    {
        "anchor": "Vector boson scattering from the lattice: We study vector-boson scattering of the physical, gauge-invariant states in a\nreduced standard-model setup on the lattice for various parameter sets. To this\nend, the phase shift in the scalar channel is determined using a L\\\"uscher-type\nanalysis. The results can be readily interpreted in terms of the Higgs\nproperties and a reunitarized Fr\\\"ohlich-Morchio-Strocchi analysis at Born\nlevel. The only deviation appears for a Higgs mass below the elastic threshold,\nwhere we find a negative scattering length indicative of the bound-state nature\nof the physical scalar degree of freedom. We assess the possible implications\nfor an experimental detection of the effect.",
        "positive": "Constrained fitting of three-point functions: We determine matrix elements for $B \\to D$ semileptonic decay. The use of the\nconstrained fitting method and multiple smearings for both two- and three-point\ncorrelators allows an improved calculation of the form factors."
    },
    {
        "anchor": "The SU(N) running coupling in the twisted gradient flow scheme and\n  volume independence: We report on an ongoing study of the running coupling of SU(N) pure\nYang-Mills theory in the twisted gradient flow scheme (TGF). The study exploits\nthe idea that twisted boundary conditions reduce finite volume effects, leading\nto an effective size in the twisted plane that combines the number of colours\nand the torus period. We test this hypothesis by computing the TGF running\ncoupling and the SU(N) $\\Lambda-$ parameter on asymmetric lattices of size\n$(NL)^2L^2$ for various gauge groups. Finite volume effects are monitored by\nanalyzing the coupling in different planes and by comparing results at\ndifferent number of colours.",
        "positive": "Excited-State Hadrons using the Stochastic LapH Method: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Large sets of spatially-extended hadron operators are used. A\nnew method of stochastically estimating the low-lying effects of quark\npropagation is utilized which allows reliable determinations of temporal\ncorrelations of both single-hadron and multi-hadron operators. The method is\ntested on the eta, sigma, omega mesons."
    },
    {
        "anchor": "Schwinger-Dyson equations and the quark-antiquark static potential: In lattice QCD, a confining potential for a static quark-antiquark pair can\nbe computed with the Wilson loop technique. This potential, dominated by a\nlinear potential at moderate distances, is consistent with the confinement with\na flux tube, an extended and scalar system also directly observable in lattice\nQCD. Quantized flux tubes have also been observed in another class of\nconfinement, the magnetic confinement in type II superconductors. On the other\nhand the solution of Schwinger Dyson Equations, say with the Landau gauge\nfixing and the truncation of the series of Feynman diagrams, already at the\nrainbow level for the self energy and at the ladder level for the Bethe\nSalpeter equation, provides a signal of a possible inverse quartic potential in\nmomentum space derived from one gluon and one ghost exchange, consistent with\nconfinement. Here we address the successes, difficulties and open problems of\nthe matching of these two different perspectives of confinement, the\nSchwinger-Dyson perspective versus the flux tube perspective.",
        "positive": "Spectra of heavy-light and heavy-heavy mesons containing charm quarks,\n  including higher spin states for $N_f=2+ 1$: We study the spectra of heavy-light and heavy-heavy mesons containing charm\nquarks, including higher spin states. We use two sets of $N_f = 2 + 1$ gauge\nconfigurations, one set from QCDSF using the SLiNC action, and the other\nconfigurations from the Budapest-Marseille-Wuppertal collaboration, using the\nHEX smeared clover action. To extract information about the excited states, we\nchoose a suitable basis of operators to implement the variational method."
    },
    {
        "anchor": "Vortices and confinement at weak coupling: We discuss the physical picture of thick vortices as the mechanism\nresponsible for confinement at arbitrarily weak coupling in SU(2) gauge theory.\nBy introducing appropriate variables on the lattice we distinguish between\nthin, thick and `hybrid' vortices, the latter involving Z(2) monopole loop\nboundaries. We present numerical lattice simulation results that demonstrate\nthat the full SU(2) string tension at weak coupling arises from the presence of\nvortices linked to the Wilson loop. Conversely, excluding linked vortices\neliminates the confining potential. The numerical results are stable under\nalternate choice of lattice action as well as a smoothing procedure which\nremoves short distance fluctuations while preserving long distance physics.",
        "positive": "$Sp(2N)$ Yang-Mills towards large $N$: Non-perturbative aspects of the physics of $Sp(2N)$ gauge theories are\ninteresting for phenomenological and theoretical reasons, and little studied so\nfar, particularly in the approach to the large-$N$ limit. We examine the\nspectrum of glueballs and the string tension of Yang-Mills theories based upon\nthese groups. Glueball masses are calculated numerically with a variational\nmethod from Monte-Carlo generated lattice gauge configurations. After taking\ncontinuum limits for $N$ = 1, 2, 3 and 4, we extrapolate the results towards\nlarge $N$. We compare the resulting spectrum with that of $SU(N)$ gauge\ntheories, both at finite $N$ and as $N$ approaches infinity."
    },
    {
        "anchor": "Eta and eta' meson masses from Nf=2+1+1 twisted mass lattice QCD: We determine mass and flavour content of eta and eta' states using Nf=2+1+1\nWilson twisted mass lattice QCD. We describe how those flavour singlet states\nneed to be treated in this lattice formulation. Results are presented for two\nvalues of the lattice spacing, a~0.08 fm and a~0.09 fm, with a range of light\nquark masses corresponding to values of the pion mass from 270 to 500 MeV and\nfixed bare strange and charm quark mass values.",
        "positive": "Observation of String Breaking in QCD: We numerically investigate the transition of the static quark-antiquark\nstring into a static-light meson-antimeson system. Improving noise reduction\ntechniques, we are able to resolve the signature of string breaking dynamics\nfor n_f=2 lattice QCD at zero temperature. This result can be related to\nproperties of quarkonium systems. We also study short-distance interactions\nbetween two static-light mesons."
    },
    {
        "anchor": "Advances in machine-learning-based sampling motivated by lattice quantum\n  chromodynamics: Sampling from known probability distributions is a ubiquitous task in\ncomputational science, underlying calculations in domains from linguistics to\nbiology and physics. Generative machine-learning (ML) models have emerged as a\npromising tool in this space, building on the success of this approach in\napplications such as image, text, and audio generation. Often, however,\ngenerative tasks in scientific domains have unique structures and features --\nsuch as complex symmetries and the requirement of exactness guarantees -- that\npresent both challenges and opportunities for ML. This Perspective outlines the\nadvances in ML-based sampling motivated by lattice quantum field theory, in\nparticular for the theory of quantum chromodynamics. Enabling calculations of\nthe structure and interactions of matter from our most fundamental\nunderstanding of particle physics, lattice quantum chromodynamics is one of the\nmain consumers of open-science supercomputing worldwide. The design of ML\nalgorithms for this application faces profound challenges, including the\nnecessity of scaling custom ML architectures to the largest supercomputers, but\nalso promises immense benefits, and is spurring a wave of development in\nML-based sampling more broadly. In lattice field theory, if this approach can\nrealize its early promise it will be a transformative step towards\nfirst-principles physics calculations in particle, nuclear and condensed matter\nphysics that are intractable with traditional approaches.",
        "positive": "On the restoration of supersymmetry in twisted two-dimensional lattice\n  Yang-Mills theory: We study a discretization of ${\\cal N}=2$ super Yang-Mills theory which\npossesses a single exact supersymmetry at non-zero lattice spacing. This\nsupersymmetry arises after a reformulation of the theory in terms of {\\it\ntwisted} fields. In this paper we derive the action of the other twisted\nsupersymmetries on the component fields and study, using Monte Carlo\nsimulation, a series of corresponding Ward identities. Our results for SU(2)\nand SU(3) support a restoration of these additional supersymmetries without\nfine tuning in the infinite volume continuum limit. Additionally we present\nevidence supporting a restoration of (twisted) rotational invariance in the\nsame limit. Finally we have examined the distribution of scalar field\neigenvalues and find evidence for power law tails extending out to large\neigenvalue. We argue that these tails indicate that the classical moduli space\ndoes not survive in the quantum theory."
    },
    {
        "anchor": "$N_f=1+2$ mass dependence of the topological susceptibility: A massless up quark has long been proposed as a solution to the strong CP\nproblem. While this solution is sometimes thought to have been excluded, it is\nactually still ill-defined. In this work, we study the mass dependence of the\nphysical observable $\\chi_t$, the topological susceptibility. Assigning an\nunphysically large value to the down mass allows to be more sensitive to the\nnon-perturbative effects behind the $m_u=0$ ambiguity. Preliminary results are\npresented for four masses of clover fermions.",
        "positive": "Impact of electromagnetism on phase structure for Wilson and\n  twisted-mass fermions including isospin breaking: In a recent paper we used chiral perturbation theory to determine the phase\ndiagram and pion spectrum for Wilson and twisted-mass fermions at non-zero\nlattice spacing with non-degenerate up and down quarks. Here we extend this\nwork to include the effects of electromagnetism, so that it is applicable to\nrecent simulations incorporating all sources of isospin breaking. For Wilson\nfermions, we find that the phase diagram is unaffected by the inclusion of\nelectromagnetism---the only effect is to raise the charged pion masses. For\nmaximally twisted fermions, we previously took the twist and isospin-breaking\ndirections to be different, in order that the fermion determinant is real and\npositive. However, this is incompatible with electromagnetic gauge invariance,\nand so here we take the twist to be in the isospin-breaking direction,\nfollowing the RM123 collaboration. We map out the phase diagram in this case,\nwhich has not previously been studied. The results differ from those obtained\nwith different twist and isospin directions. One practical issue when including\nelectromagnetism is that the critical masses for up and down quarks differ. We\nshow that one of the criteria suggested to determine these critical masses does\nnot work, and propose an alternative."
    },
    {
        "anchor": "Confinement of quarks in higher representations in view of dual\n  superconductivity: Dual superconductor picture is one of the most promising scenarios for quark\nconfinement. We have proposed a new formulation of Yang-Mills theory on the\nlattice so that the so-called restricted field obtained from the\ngauge-covariant decomposition plays the dominant role in quark confinement.\nThis framework improves the Abelian projection in the gauge-independent manner.\nFor quarks in the fundamental representation, we have demonstrated some\nnumerical evidences for the dual superconductivity. However, it is known that\nthe expected behavior of the Wilson loop in higher representations cannot be\nreproduced if the restricted part of the Wilson loop is extracted by adopting\nthe Abelian projection or the field decomposition naively in the same way as in\nthe fundamental representation. In this talk, therefore, we focus on\nconfinement of quarks in higher representations. By virtue of the non-Abelian\nStokes theorem for the Wilson loop operator, we propose suitable operators\nconstructed from the restricted field only in the fundamental representation to\nreproduce the correct behavior of the original Wilson loop in higher\nrepresentations. Moreover, we perform lattice simulations to measure the static\npotential for quarks in higher representations using the proposed operators. We\nfind that the proposed operators well reproduce the expected behavior of the\noriginal Wilson loop average, which overcomes the problem that occurs in\nnaively applying Abelian-projection to the Wilson loop operator for higher\nrepresentations.",
        "positive": "Effects of Topology in the Dirac Spectrum of Staggered Fermions: We compare the lower edge spectral fluctuations of the staggered lattice\nDirac operator for the Schwinger model with the predictions of chiral Random\nMatrix Theory (chRMT). We verify their range of applicability, checking in\nparticular the role of non-trivial topological sectors and the flavor symmetry\nof the staggered fermions for finite lattice spacing. Approaching the continuum\nlimit we indeed find clear signals for topological modes in the eigenvalue\nspectrum. These findings indicate problems in the verification of the chRMT\npredictions."
    },
    {
        "anchor": "Gauge-Invariant Noncompact Lattice Simulations: Three techniques for performing gauge-invariant, noncompact lattice\nsimulations of nonabelian gauge theories are discussed.\n  In the first method, the action is not itself gauge invariant, but a kind of\nlattice gauge invariance is restored by random compact gauge transformations\nduring the successive sweeps of the simulation. This method has been applied to\npure $SU(2)$ gauge theory on a $12^4$ lattice, and Wilson loops have been\nmeasured at strong coupling, $\\beta=0.5$. These Wilson loops display a\nconfinement signal not seen in simulations performed earlier with the same\naction but without the random gauge transformations.\n  In the second method, the action is gauge symmetrized by integrations over\nthe group manifold.\n  The third method is based upon a new, noncompact form of the action that is\nexactly invariant under lattice gauge transformations. The action is a natural\ndiscretization of the classical Yang-Mills action.",
        "positive": "Heavy quark free energies for three quark systems at finite temperature: We study the free energy of static three quark systems in singlet, octet,\ndecuplet and average color channels in the quenched approximation and in\n2-flavor QCD at finite temperature. We show that in the high temperature phase\nsinglet and decuplet free energies of three quark systems are well described by\nthe sum of the free energies of three diquark systems plus self energy\ncontributions of the three quarks. In the confining low temperature phase we\nfind evidence for a Y-shaped flux tube in SU(3) pure gauge theory, which is\nless evident in 2-flavor QCD due to the onset of string breaking. We also\ncompare the short distance behavior of octet and decuplet free energies to the\nfree energies of single static quarks in the corresponding color\nrepresentations."
    },
    {
        "anchor": "Spectrum of the Hermitian Wilson Dirac operator: Recent results on the spectral properties of the Hermitian Wilson-Dirac\noperator are presented.",
        "positive": "An ``Improved\" Lattice Study of Semi-leptonic Decays of D-Mesons: We present results of a lattice computation of the matrix elements of the\nvector and axial-vector currents which are relevant for the semi-leptonic\ndecays $D \\rightarrow K$ and $D \\rightarrow K^*$. The computations are\nperformed in the quenched approximation to lattice QCD on a $24^3 \\times 48$\nlattice at $\\beta=6.2$, using an $O(a)$-improved fermionic action. In the limit\nof zero lepton masses the semi-leptonic decays $D \\rightarrow K$ and $D\n\\rightarrow K^*$ are described by four form factors: $f^{+}_K,V,A_1$ and $A_2$,\nwhich are functions of $q^2$, where $q^{\\mu}$ is the four-momentum transferred\nin the process. Our results for these form factors at $q^2=0$ are:\n$f^+_K(0)=0.67 \\er{7}{8}$ , $V(0)=1.01 \\err{30}{13}$ , $A_1(0)=0.70\n\\err{7}{10}$ , $A_2(0)=0.66 \\err{10}{15}$ , which are consistent with the most\nrecent experimental world average values. We have also determined the $q^2$\ndependence of the form factors, which we find to be reasonably well described\nby a simple pole-dominance model. Results for other form factors, including\nthose relevant to the decays \\dpi and \\drho, are also given."
    },
    {
        "anchor": "Off-forward gluonic structure of vector mesons: The spin-independent and transversity generalised form factors (GFFs) of the\n$\\phi$ meson are studied using lattice QCD calculations with light quark masses\ncorresponding to a pion mass $m_\\pi\\sim450(5)$ MeV. One transversity and three\nspin-independent GFFs related to the lowest moments of leading-twist\nspin-independent and transversity gluon distributions are obtained at six\nnon-zero values of the momentum transfer up to 1.2 GeV$^2$. These quantities\nare compared with the analogous spin-independent quark GFFs and the\nelectromagnetic form factors determined on the same lattice ensemble. The\nresults show quantitative distinction between the spatial distribution of\ntransversely polarised gluons, unpolarised gluons, and quarks, and point the\nway towards further investigations of the gluon structure of nucleons and\nnuclei.",
        "positive": "Neutral $\u03c1$ and $A$ mesons in magnetic field in SU(2) lattice gauge\n  theory: Correlators of vector, axial and pseudoscalar currents have been calculated\nin external strong magnetic field in SU(2) gluodynamics on the lattice. Neutral\n$\\rho$ and $A$ meson masses with a zero spin projection to the axis parallel to\nthe external magnetic field $B$ are calculated. The mass of the neutral $\\rho$\nmeson with zero spin decreases with increasing of the magnetic field for\navailable values of the magnetic field $eB\\lesssim 2-2.5\\, \\Gev^2$, such\nbehavior is necessary for a condensation of $\\rho$ mesons in a strong magnetic\nfield."
    },
    {
        "anchor": "Dependence of Lattice Hadron Masses on External Magnetic Fields: We study the variation of the hadron masses in the presence of external\nmagnetic fields of strength of the order of the masses themselves. We identify\nthe main factors affecting the lattice simulation results: - the boundary\ndiscontinuities for $eB << 2\\pi / L^2 a^2$. - the SU(6) choice of the hadron\nwave-function. We confirm qualitatively the earlier theoretical ansatz on the\nlinear behaviour of the masses with the magnetic field and, as a by-product, we\nimprove the lattice measurements of the nucleon magnetic moments. However our\nsystematic and statistical errors preclude us from measuring the theoretically\npredicted field strength at which the proton becomes heavier than the neutron.",
        "positive": "Operator product expansion and non-perturbative renormalization: It has been recently proposed to use the operator product expansion to\nevaluate the expectation values of renormalized operators without the need of a\ndirect computation of the relevant renormalization constants. We test the\nviability of this idea in the two-dimensional non-linear sigma-model discussing\nthe non-perturbative renormalization of the energy-momentum tensor."
    },
    {
        "anchor": "Strong coupling constant and quark masses from lattice QCD: We review lattice determinations of the charm and bottom quark masses and the\nstrong coupling constant obtained by different methods. We explain how\neffective field theory approaches, such as Non-Relativistic QCD (NRQCD),\npotential Non-Relativistic QCD (pNRQCD), Heavy Quark Effective Theory (HQET)\nand Heavy Meson rooted All-Staggered Chiral Perturbation Theory (HMrAS$\\chi$PT)\ncan help in these determinations. After critically reviewing different lattice\nresults we determine lattice world averages for the strong coupling constant,\n$\\alpha_s(M_Z,N_f{=}5)=0.11803^{+0.00047}_{-0.00068}$, as well as for the charm\nquark mass, $m_c(m_c,N_f{=}4)=1.2735(35)$ GeV, and the bottom quark mass,\n$m_b(m_b,N_f{=}5)=4.188(10)$ GeV. The above determinations are more precise\nthan the ones obtained by Particle Data Group (PDG).",
        "positive": "Optimal lattice domain-wall fermions: I show that the conventional formulations of lattice domain-wall fermion with\nany finite N_s (in the fifth dimension) do not preserve the chiral symmetry\noptimally and propose a new action which preserves the chiral symmetry\noptimally for any finite N_s."
    },
    {
        "anchor": "Scalar and Vector 4Q Systems in Anisotropic Lattice QCD: We present a detailed study of some $4q$ hadrons in quenched improved\nanisotropic lattice QCD. Using the $\\pi\\pi$ and diquark-antidiquark local and\nsmeared operators, we attempt to isolate the signal for $I(J^{P})=0(0^{+}),\n2(0^{+})$ and $1(1^{+})$ states in two flavour QCD. In the chiral limit of\nlight-quark mass region, the lowest scalar $4q$ state is found to have a mass,\n$m^{I=0}_{4q}=927(12)$ MeV, which is slightly lower than the experimentally\nobserved $f_{0}(980)$. The results from our variational analysis do not\nindicate a signature of a tetraquark resonance in I=1 and I=2 channels. After\nthe chiral extrapolation the lowest $1(1^{+})$ state is found to have a mass,\n$m^{I=1}_{4q}=1358(28)$ MeV. We analysed the static $4q$ potential extracted\nform a tetraquark Wilson loop and illustrated the behaviour of the $4q$ state\nas a bound state, unbinding at some critical diquark separation.\n  From our analysis we conclude that scalar $4q$ system appears as a two-pion\nscattering state and that there is no spatially-localised $4q$ state in the\nlight-quark mass region.",
        "positive": "Mass and Axial current renormalization in the Schr\u00f6dinger functional\n  scheme for the RG-improved gauge and the stout smeared $O(a)$-improved Wilson\n  quark actions: We present the quark mass and axial current renormalization factors for the\nRG-improved Iwasaki gauge action and three flavors of the stout smeared\n$O(a)$-improved Wilson quark action. We employ $\\alpha=0.1$ and\n$n_{\\mathrm{step}}=6$ for the stout link smearing parameters and all links in\nthe quark action are replaced with the smeared links. Using the Schr\\\"{o}dinger\nfunctional scheme we evaluate the renormalization factors at $\\beta=1.82$ where\nlarge scale simulations are being carried out."
    },
    {
        "anchor": "Tensor polarizability of the vector mesons from $SU(3)$ lattice gauge\n  theory: The magnetic dipole polarizabilities of the vector $\\rho^0$ and $\\rho^{\\pm}$\nmesons in $SU(3)$ pure gauge theory are calculated in the article. Based on\nthis the authors explore the contribution of the dipole magnetic\npolarizabilities to the tensor polarization of the vector mesons in external\nabelian magnetic field. The tensor polarization leads to the dilepton asymmetry\nobserved in non-central heavy ion collisions and can be also estimated in\nlattice gauge theory.",
        "positive": "Beyond Complex Langevin Equations: positive representation of a class of\n  complex measures: A positive representation for a set of complex densities is constructed. In\nparticular, complex measures on a direct product of U(1) groups are studied.\nAfter identifying general conditions which such representations should satisfy,\nseveral explicit realizations are proposed. Their utility is illustrated in few\nconcrete examples representing problems in abelian lattice gauge theories."
    },
    {
        "anchor": "Some peculiarities of transition from discrete to continuum Fourier\n  series in lattice theories: Transition from discrete to continuous Fourier series is studied for the\nfunctions becoming singular in the transition. Conditions are specified when\nsumming replacement by integration is inadmissible.",
        "positive": "Probing singularities of Landau-gauge propagators with Pad\u00e9\n  approximants: Pad\\'e approximants are employed in order to study the analytic structure of\nthe four-dimensional SU(2) Landau-gauge gluon and ghost propagators in the\ninfrared regime. The approximants, which are model independent, are used as\nfitting functions to lattice data for the propagators, carefully propagating\nuncertainties due to the fit procedure and taking into account all possible\ncorrelations. Applying this procedure systematically to the gluon-propagator\ndata, we observe the presence of a pair of complex poles at\n$p^2_{\\mathrm{pole}} = (-0.37 \\pm 0.05_{\\mathrm{stat}} \\pm 0.08_{\\mathrm{sys}})\n\\pm \\, i\\, (0.66 \\pm 0.03_{\\mathrm{stat}} \\pm 0.02_{\\mathrm{sys}}) \\,\n\\mathrm{GeV}^2$, where ``stat'' represents the statistical error and ``sys''\nthe systematic one. We also find a zero on the negative real axis of $p^2$, at\n$p^2_{\\mathrm{zero}} = (-2.9 \\pm 0.4_{\\mathrm{stat}} \\pm 0.9_{\\mathrm{sys}}) \\,\n\\mathrm{GeV}^2$. We thus note that our procedure -- which is based on a\nmodel-independent approach and includes careful error propagation -- confirms\nthe presence of a pair of complex poles in the gluon propagator, in agreement\nwith previous works. For the ghost propagator, the Pad\\'es indicate the\nexistence of the single pole at $p^2 = 0$, as expected. We also find evidence\nof a branch cut on the negative real axis. Through the use of the so-called\nD-Log Pad\\'e method, which is designed to approximate functions with cuts, we\ncorroborate the existence of this cut for the ghost propagator."
    },
    {
        "anchor": "Monopole gas in three dimensional SU(2) gluodynamics: We study properties of the Abelian monopoles in the Maximal Abelian\nprojection of the three dimensional pure SU(2) gauge model. We match the\nlattice monopole dynamics with the continuum Coulomb gas model using a method\nof blocking from continuum. We obtain the Debye screening length and the\nmonopole density in continuum using numerical results for the lattice density\nof the (squared) monopole charges and for the monopole action. The monopoles\ntreated within our blocking method provide about 75% contribution to the\nnon--Abelian Debye screening length. We also find that monopoles form a Coulomb\nplasma which is not dilute.",
        "positive": "Complex Langevin in low-dimensional QCD: the good and the not-so-good: We present our latest results on the application of the complex Langevin\nmethod to one- and two-dimensional QCD. Although the method is stable, it\nunfortunately converges to an incorrect result when applied as such. After\napplying additional gauge cooling steps, the results agree with the known\nanalytical results in the one-dimensional case. However, in the two-dimensional\ncase the disagreement subsists, even with gauge cooling, when the sign problem\nis sufficiently large."
    },
    {
        "anchor": "High-Precision $f_{B_s}$ and HQET from Relativistic Lattice QCD: We present a new determination of the $B_s$ leptonic decay constant from\nlattice QCD simulations that use gluon configurations from MILC and a highly\nimproved discretization of the relativistic quark action for both valence\nquarks. Our result, $f_{B_s} = 0.225(4)$\\,GeV, is almost three times more\naccurate than previous determinations. We analyze the dependence of the decay\nconstant on the heavy quark's mass and obtain the first empirical evidence for\nthe leading $1/\\sqrt{m_h}$ dependence predicted by Heavy Quark Effective Theory\n(HQET). As a check, we use our analysis technique to calculate the\n$m_{B_s}-m_{\\eta_b}/2$ mass difference. Our result agrees with experiment to\nwithin errors of $11\\,\\mathrm{MeV}$ (better than 2%). We discuss how to extend\nour analysis to other quantities in $B_s$ and $B$ physics, making 2%-precision\npossible for the first time.",
        "positive": "Chiral Symmetry Breaking in Strongly Coupled Quenched QED$_4$ Using the\n  Dyson-Schwinger Equation Formalism: We study chiral symmetry breaking in quenched strong-coupling QED$_4$ in\narbitrary covariant gauge within the Dyson-Schwinger equation formalism. A\nrecently developed numerical renormalization program is fully implemented.\nResults are compared for three different fermion-photon proper vertex {\\it\nAns\\\"{a}tze\\/}: bare $\\gamma^\\mu$, minimal Ball-Chiu, and Curtis-Pennington.\nThe procedure is straightforward to implement and numerically stable. We\ndiscuss the chiral limit and observe that in this limit the renormalized axial\ncurrent is conserved. A detailed study of residual gauge dependence due to the\nvertex choice is in progress. The relevance for lattice studies is discussed."
    },
    {
        "anchor": "New insight in the 2-flavor Schwinger model based on lattice simulations: We consider the Schwinger model with two degenerate, light fermion flavors by\nmeans of lattice simulations. At finite temperature, we probe the viability of\na bosonization method by Hosotani et al. Next we explore an analogue to the\npion decay constant, which agrees for independent formulations based on the\nGell-Mann--Oakes--Renner relation, the 2-dimensional Witten--Veneziano formula\nand the $\\delta$-regime. Finally we confront several conjectures about the\nchiral condensate with lattice results.",
        "positive": "Heavy flavor physics from lattice QCD: We review recent progress on heavy flavor physics from lattice QCD."
    },
    {
        "anchor": "Variational analysis of low-lying states in supersymmetric Yang-Mills\n  theory: We have calculated the masses of bound states numerically in N = 1\nsupersymmetric Yang-Mills theory with gauge group SU(2). Using the suitably\noptimised variational method with an operator basis consisting of smeared\nWilson loops and mesonic operators, we are able to obtain the masses of the\nground states and first excited states in the scalar, pseudoscalar and spin-1/2\nsectors. Extrapolated to the continuum limit, the corresponding particles\nappear to be approximately mass degenerate and to fit into the predicted chiral\nsupermultiplets. The extended operator basis including both glueball-like and\nmesonic operators leads to improved results compared to earlier studies, and\nmoreover allows us to investigate the mixing content of the physical states,\nwhich we compare to predictions in the literature.",
        "positive": "Perturbative renormalization of bilinear quark and gluon operators: The renormalisation constants for local bilinear quark operators are\ncalculated using the Sheikholeslami-Wohlert improved action. In addition we\ncompute the renormalisation constant of the leading gluon operator for\ndifferent group representations and discuss the mixing of the operators E^2 and\nB^2."
    },
    {
        "anchor": "Evidence for BCS Diquark Condensation in the 3+1d Lattice NJL Model: We present results of numerical simulations of the 3+1d Nambu - Jona-Lasinio\nmodel with a non-zero baryon chemical potential mu, with particular emphasis on\nthe superfluid diquark condensate and associated susceptibilities. The results,\nwhen extrapolated to the zero diquark source limit, are consistent with the\nexistence of a non-zero BCS condensate at high baryon density. The nature of\nthe infinite volume and zero temperature limits are discussed.",
        "positive": "Numerical Simulations of an SU(2)_L x SU(2)_R-symmetric Higgs-Yukawa\n  Model on the QUADRICS Q16: We report on our work on the SU(2)_L x SU(2)_R symmetric Higgs Yukawa Model\nwith mirror fermion action. Our model describes a fermion Higgs system in the\nlimit of vanishing gauge coupling. Setting the bare Yukawa coupling of the\nmirror fermions G_\\chi to zero, we want to determine the triviality bounds on\nthe renormalized Yukawa coupling of the fermions G_{R\\psi} and the scalar\nself-coupling g_R on 8^3x16 and 16^3x32 lattices."
    },
    {
        "anchor": "Euclidean Dynamical Triangulation revisited: is the phase transition\n  really 1st order? (extended version): The transition between the two phases of 4D Euclidean Dynamical Triangulation\n[1] was long believed to be of second order until in 1996 first order behavior\nwas found for sufficiently large systems [5,9]. However, one may wonder if this\nfinding was affected by the numerical methods used: to control volume\nfluctuations, in both studies [5,9] an artificial harmonic potential was added\nto the action; in [9] measurements were taken after a fixed number of accepted\ninstead of attempted moves which introduces an additional error. Finally the\nsimulations suffer from strong critical slowing down which may have been\nunderestimated. In the present work, we address the above weaknesses: we allow\nthe volume to fluctuate freely within a fixed interval; we take measurements\nafter a fixed number of attempted moves; and we overcome critical slowing down\nby using an optimized parallel tempering algorithm [12]. With these improved\nmethods, on systems of size up to 64k 4-simplices, we confirm that the phase\ntransition is first order.\n  In addition, we discuss a local criterion to decide whether parts of a\ntriangulation are in the elongated or crumpled state and describe a new\ncorrespondence between EDT and the balls in boxes model. The latter gives rise\nto a modified partition function with an additional, third coupling. Finally,\nwe propose and motivate a class of modified path-integral measures that might\nremove the metastability of the Markov chain and turn the phase transition into\nsecond order.",
        "positive": "Chiral forms and three-flavor operators for staggered baryons: In staggered QCD, many staggered baryons correspond to each physical state.\nTaste violations lift the continuum degeneracies of the baryons and introduce\nnonzero off-diagonal elements in the mass matrix. While presenting no problem\nof principle, these splittings and mixings complicate analyses of simulation\nresults. However, in special cases operators with good SU(3) quantum numbers\ncan be used to circumvent the splittings and mixings. I review what has been\nlearned from staggered chiral perturbation theory, outline a program of attack\nfor the amenable cases, and summarize the present status of work on the\nstaggered chiral forms and operators with good SU(3)xGTS quantum numbers."
    },
    {
        "anchor": "Yet another lattice formulation of 2D $U(1)$ chiral gauge theory via\n  bosonization: Recently, lattice formulations of Abelian chiral gauge theory in two\ndimensions have been devised on the basis of the Abelian bosonization. A\nsalient feature of these two-dimensional lattice formulations is that the gauge\ninvariance is \\emph{exactly\\/} preserved for anomaly-free theories and thus is\ncompletely free from the question of the gauge mode decoupling. In the present\npaper, we propose a yet another lattice formulation sharing this desired\nproperty. A particularly unique point in our formulation is that the vertex\noperator of the dual scalar field, which carries the vector charge of the\nfermion and the ``magnetic charge'' in the bosonization, is represented by a\n``hole'' excised from the lattice; this is the excision method formulated\nrecently by Abe et al. in a somewhat different context.",
        "positive": "Direct determinations of the nucleon and pion $\u03c3$ terms at nearly\n  physical quark masses: We present a high statistics study of the pion and nucleon light and strange\nquark sigma terms using $N_f=2$ dynamical non-perturbatively improved clover\nfermions with a range of pion masses down to $m_\\pi\\sim 150$ MeV and several\nvolumes, $Lm_\\pi=3.4$ up to $6.7$, and lattice spacings, $a=0.06-0.08$ fm,\nenabling a study of finite volume and discretisation effects for $m_\\pi\\gtrsim\n260$ MeV. Systematics are found to be reasonably under control. For the nucleon\nwe obtain $\\sigma_{\\pi N}=35(6)$ MeV and $\\sigma_s=35(12)$ MeV, or equivalently\nin terms of the quark fractions, $f_{T_u}=0.021(4)$, $f_{T_d}=0.016(4)$ and\n$f_{T_s}=0.037(13)$, where the errors include estimates of both the systematic\nand statistical uncertainties. These values, together with perturbative\nmatching in the heavy quark limit, lead to $f_{T_c}=0.075(4)$,\n$f_{T_b}=0.072(2)$ and $f_{T_t}=0.070(1)$. In addition, through the use of the\n(inverse) Feynman-Hellmann theorem our results for $\\sigma_{\\pi N}$ are shown\nto be consistent with the nucleon masses determined in the analysis. For the\npion we implement a method which greatly reduces excited state contamination to\nthe scalar matrix elements from states travelling across the temporal boundary.\nThis enables us to demonstrate the Gell-Mann-Oakes-Renner expectation\n$\\sigma_\\pi=m_\\pi/2$ over our range of pion masses."
    },
    {
        "anchor": "From enemies to friends: chiral symmetry on the lattice: The physics of strong interactions is invariant under the exchange of\nleft-handed and right-handed quarks, at least in the massless limit. This\ninvariance is reflected in the chiral symmetry of quantum chromodynamics.\nSurprisingly, it has become clear only recently how to implement this important\nsymmetry in lattice formulations of quantum field theories. We will discuss\nrealizations of exact lattice chiral symmetry and give an example of the\ncomputation of a physical observable in quantum chromodynamics where chiral\nsymmetry is important. This calculation is performed by relying on finite size\nscaling methods as predicted by chiral perturbation theory.",
        "positive": "Non-perturbative Renormalization of Lattice Operators: We briefly review and compare three methods (one perturbative, one based on\nWard Identities and one non-perturbative) for the calculation of the\nrenormalization constants of lattice operators. The following results are\npresented: (a) non perturbative renormalization of the operators with light\nquarks; (b) the renormalization constants with a heavy (charm) quark mass and\nits KLM improvement; (c) the non perturbative determination of the mixing of\nthe $\\Delta S = 2$ operator."
    },
    {
        "anchor": "Scaling of the Upsilon Spectrum in Lattice NRQCD: We present results for the spectrum of b-bbar bound states in the quenched\napproximation for three different values of the lattice spacing, in the range\n0.05fm to 0.15fm. We find our results for spin-independent splittings in\nphysical units to be independent of the lattice spacing, indicating the absence\nof systematic errors from discretisation effects. Spin-dependent splittings are\nmore sensitive to the lattice spacing and higher order corrections to the\naction; we discuss the size of these effects and what can be done to arrive at\na physical result.",
        "positive": "On projection (in)dependence of monopole condensate in lattice SU(2)\n  gauge theory: We study the temperature dependence of the monopole condensate in different\nAbelian projections of the SU(2) lattice gauge theory. Using the\nFrohlich-Marchetti monopole creation operator we show numerically that the\nmonopole condensate depends on the choice of the Abelian projection. Contrary\nto the claims in the current literature we observe that in the Abelian Polyakov\ngauge and in the field strength gauge the monopole condensate does not vanish\nat the critical temperature and thus is not an order parameter."
    },
    {
        "anchor": "High order quark number susceptibilities in hot QCD from lattice EQCD: Building on the experience of [1], we develop a formalism to construct\noperators for higher derivatives of the pressure in hot QCD with respect to the\nquark chemical potential $\\mu$. We provide formulae for the operators up to the\nsixth derivative, and obtain continuum-extrapolated results from lattice EQCD\nat zero and finite $\\mu$ and at six different pairs of temperature T and number\nof massless quark flavors $n_f$. Our data is benchmarked against full-QCD\nlattice and perturbative results, allowing to judge the quality of the\nperturbative series expansion in EQCD and the dimensional reduction procedure\nas a whole.",
        "positive": "The spin structure of the pion: We present the first calculation of the transverse spin structure of the pion\nin lattice QCD. Our simulations are based on two flavors of non-perturbatively\nimproved Wilson fermions, with pion masses as low as 400 MeV in volumes up to\n(2.1 fm)^3 and lattice spacings below 0.1 fm. We find a characteristic\nasymmetry in the spatial distribution of transversely polarized quarks. This\nasymmetry is very similar in magnitude to the analogous asymmetry we previously\nobtained for quarks in the nucleon. Our results support the hypothesis that all\nBoer-Mulders functions are alike."
    },
    {
        "anchor": "Random matrix triality at nonzero chemical potential: We introduce three universality classes of chiral random matrix ensembles\nwith a nonzero chemical potential and real, complex or quaternion real matrix\nelements. In the thermodynamic limit we find that the distribution of the\neigenvalues in the complex plane does not depend on the Dyson index, and is\ngiven by the solution proposed by Stephanov. For a finite number of degrees of\nfreedom, $N$, we find an accumulation of eigenvalues on the imaginary axis for\nreal matrices, whereas for quaternion real matrices we find a depletion of\neigenvalues in this domain. This effect is of order $1/\\sqrt N$. In particular\nfor the real case the resolvent shows a discontinuity of order $1/\\sqrt N$.\nThese results are in agreement with lattice QCD simulations with staggered\nfermions and recent instanton liquid simulations both for two colors and\nnonzero chemical potential.",
        "positive": "Pseudoscalar singlet physics with staggered fermions: We report on progress in measuring disconnected correlators associated with\npseudoscalar flavor-singlet mesons. This will eventually allow us to compute\nthe masses of the eta and eta' mesons. Flavor-singlet physics also presents an\ninteresting test of the staggered fermion formulation, as disconnected\ncorrelators are sensitive to whether the same action governs both sea quarks\nand valence quarks. It can also help test the validity of the ``fourth-root\ntrick'' used in unquenched lattice calculations where the number of flavors\n$N_f<4$."
    },
    {
        "anchor": "Lattice Approach to the $\u0394I=1/2$ Rule: We discuss a number of old and new methods for computing $K\\to\\pi\\pi$\namplitudes on the lattice. They all involve a non-perturbative determination of\nmatching coefficients. We show how problems related to operator mixing can be\ngreatly reduced by using point-split hadronic currents.",
        "positive": "Classification of Supersymmetric Lattice Gauge Theories by Orbifolding: We provide a general classification of supersymmetric lattice gauge theories\nthat can be obtained from orbifolding of theories with four and eight\nsupercharges. We impose at least one preserved supercharge on the lattice and\nLorentz invariance in the naive continuum limit. Starting with four\nsupercharges, we obtain one two-dimensional lattice gauge theory, identical to\nthe one already given in the literature. Starting with eight supercharges, we\nobtain a unique three-dimensional lattice gauge theory and infinitely many\ntwo-dimensional lattice theories. They can be classified according to seven\ndistinct groups, five of which have two preserved supercharges while the others\nhave only one."
    },
    {
        "anchor": "Lattice QCD with light Wilson quarks: Wilson's formulation of lattice QCD is attractive for many reasons, but\nperhaps mainly because of its simplicity and conceptual clarity. Numerical\nsimulations of the Wilson theory (and of its improved versions) tend to be\nextremely demanding, however, to the extent that they rapidly become\nimpractical at small quark masses. Recent advances in simulation algorithms now\nallow such simulations to be pushed to significantly smaller masses without\nhaving to compromise in other ways. Contact with chiral perturbation theory can\nthus be made and many physics questions can be addressed that previously\nappeared to be inaccessible.",
        "positive": "Three-dimensional Gross-Neveu model with two flavors of staggered\n  fermions: We introduce a strongly interacting lattice field theory model containing two\nflavors of massless staggered fermions with two kinds of interactions: (1) a\nlattice current-current interaction, and (2) an on-site four-fermion\ninteraction. At weak couplings, we expect a massless fermion phase since our\ninteractions become irrelevant at long distances. At strong couplings, based on\nprevious studies, we argue that our lattice model contains two different\nmassive fermion phases with different mechanisms of fermion mass generation. In\none phase, fermions become massive through Spontaneous Symmetry Breaking (SSB)\nvia the formation of a fermion bilinear condensate. In the other phase, fermion\nmass arises through a more exotic mechanism without the formation of any\nfermion bilinear condensate. Our lattice model is free of sign problems and can\nbe studied using the fermion bag algorithm. The longer term goal here is to\nstudy both these mass generation phenomena in a single model and understand how\ndifferent phases come together."
    },
    {
        "anchor": "Topology conserving gauge action and the overlap-Dirac operator: We apply the topology conserving gauge action proposed by Luescher to the\nfour-dimensional lattice QCD simulation in the quenched approximation. With\nthis gauge action the topological charge is stabilized along the hybrid Monte\nCarlo updates compared to the standard Wilson gauge action. The quark potential\nand renormalized coupling constant are in good agreement with the results\nobtained with the Wilson gauge action. We also investigate the low-lying\neigenvalue distribution of the hermitian Wilson-Dirac operator, which is\nrelevant for the construction of the overlap-Dirac operator.",
        "positive": "Properties of the QCD thermal transition with $N_f=2+1$ flavours of\n  Wilson quark: We study properties of the thermal transition in QCD, using anisotropic,\nfixed-scale lattice simulations with $N_f = 2+1$ flavours of Wilson fermion.\nObservables are compared for two values of the pion mass, focusing on chiral\nproperties. Results are presented for the Polyakov loop, various\nsusceptibilities, the chiral condensate and its susceptibility, and the onset\nof parity doubling in the light and strange baryonic sector."
    },
    {
        "anchor": "Exact chiral symmetry on the lattice and the Ginsparg-Wilson relation: It is shown that the Ginsparg-Wilson relation implies an exact symmetry of\nthe fermion action, which may be regarded as a lattice form of an infinitesimal\nchiral rotation. Using this result it is straightforward to construct lattice\nYukawa models with unbroken flavour and chiral symmetries and no doubling of\nthe fermion spectrum. A contradiction with the Nielsen-Ninomiya theorem is\navoided, because the chiral symmetry is realized in a different way than has\nbeen assumed when proving the theorem.",
        "positive": "Detecting chiral singularities in lattice QCD at strong coupling: We study the difficulties associated with detecting chiral singularities in\nstrongly coupled lattice QCD at fixed nonzero tempearture. We show that the\nbehavior of the chiral condensate, the pion mass and the pion decay constant,\nfor small masses, are all consistent with the predictions of Chiral\nPerturbation Theory. However, the values of the quark masses that we need to\ndemonstrate this are much smaller than those being used in dynamical QCD\nsimulations."
    },
    {
        "anchor": "Perturbative subtraction of lattice artifacts in the computation of\n  renormalization constants: The determination of renormalization factors is of crucial importance. They\nrelate the observables obtained on finite, discrete lattices to their measured\ncounterparts in the continuum in a suitable renormalization scheme. Therefore,\nthey have to be computed as precisely as possible. A widely used approach is\nthe nonperturbative Rome-Southampton method. It requires, however, a careful\ntreatment of lattice artifacts. They are always present because simulations are\ndone at lattice spacings $a$ and momenta $p$ with $ap$ not necessarily small.\nIn this paper we try to suppress these artifacts by subtraction of one-loop\ncontributions in lattice perturbation theory. We compare results obtained from\na complete one-loop subtraction with those calculated for a subtraction of\n$O(a^2)$.",
        "positive": "Lee-Yang zero analysis for the study of QCD phase structure: We comment on the Lee-Yang zero analysis for the study of the phase structure\nof QCD at high temperature and baryon number density by Monte-Carlo\nsimulations. We find that the sign problem for non-zero density QCD induces a\nserious problem in the finite volume scaling analysis of the Lee-Yang zeros for\nthe investigation of the order of the phase transition. If the sign problem\noccurs at large volume, the Lee-Yang zeros will always approach the real axis\nof the complex parameter plane in the thermodynamic limit. This implies that a\nscaling behavior which would suggest a crossover transition will not be\nobtained. To clarify this problem, we discuss the Lee-Yang zero analysis for\nSU(3) pure gauge theory as a simple example without the sign problem, and then\nconsider the case of non-zero density QCD. It is suggested that the\ndistribution of the Lee-Yang zeros in the complex parameter space obtained by\neach simulation could be more important information for the investigation of\nthe critical endpoint in the $(T, \\mu_q)$ plane than the finite volume scaling\nbehavior."
    },
    {
        "anchor": "The Quest for Light Sea Quarks: Algorithms for the Future: As part of a systematic algorithm study, we present first results on a\nperformance comparison between a multibosonic algorithm and the hybrid Monte\nCarlo algorithm as employed by the SESAM collaboration. The standard Wilson\nfermion action is used on 32*16^3 lattices at beta=5.5.",
        "positive": "Gluon mass at finite temperature in Landau gauge: Using lattice results for the Landau gauge gluon propagator at finite\ntemperature, we investigate its interpretation as a massive type bosonic\npropagator. In particular, we estimate a gluon mass from Yukawa-like fits to\nthe lattice data and study its temperature dependence."
    },
    {
        "anchor": "Block renormalization group transformations and overlap fermions: In this preliminary work, I provide the outline of an argument (leaving the\nfull proof to a future publication) that there exists a valid renormalization\ngroup blocking transformation which converts the continuum fermion action into\na Ginsparg-Wilson lattice action. I construct the blocking for the massless\noverlap operator as a specific example, indicating how other Ginsparg-Wilson\nlattice Dirac operators can be derived in a similar fashion. This\nrenormalization group transformation modifies the gauge action and adds a\nnumber of irrelevant terms to the lattice action. The procedure is not valid\nfor lattice Dirac operators which do not exactly satisfy the Ginsparg-Wilson\nrelation, for example the Wilson operator.",
        "positive": "Finite Density $QED_{1+1}$ Near Lefschetz Thimbles: One strategy for reducing the sign problem in finite-density field theories\nis to deform the path integral contour from real to complex fields. If the\ndeformed manifold is the appropriate combination of Lefschetz thimbles -- or\nsomewhat close to them -- the sign problem is alleviated. Gauge theories lack a\nwell-defined thimble decomposition, and therefore it is unclear how to carry\nout a generalized thimble method. In this paper we discuss some of the\nconceptual issues involved by applying this method to $QED_{1+1}$ at finite\ndensity, showing that the generalized thimble method yields correct results\nwith less computational effort than standard methods."
    },
    {
        "anchor": "Quantum thermalization of gauge theories: chaos, turbulence and\n  universality: In this talk, we discuss real-time thermalization dynamics of $\\mathbf{Z}_2$\nLattice Gauge Theory in 2+1 spacetime dimensions. While classical\nthermalization is commonly associated with chaotic behavior, turbulence and\nuniversality, the manifestation of these phenomena in quantum mechanical\nsystems is not clear. However, when viewed through the lens of Entanglement\nStructure, we find that quantum thermalization proceeds in characteristic\nstages and reveals phenomena remarkably similar to their classical\ncounterparts: chaos, turbulence and universality.",
        "positive": "Exploring the Aoki regime: We compute next-to-leading order (NLO) corrections in the \\epsilon-regime of\nWilson (WChPT) and Staggered Chiral Perturbation Theory (SChPT). A difference\nbetween the two is that in WChPT already at NLO, that is at O(\\epsilon^2), new\nlow energy constants (LECs) contribute, whereas in SChPT they only enter at\nO(\\epsilon^4). We first determine the NLO corrections in WChPT for SU(2), and\nfor U(N_f) at fixed index. This implies finite-volume corrections to the phase\nboundary between the Aoki phase and the Sharpe-Singleton scenario via\ncorrections to the mean field potential. We also compute NLO corrections to the\ntwo-point function in the scalar and pseudo-scalar sector in WChPT. Turning to\nSChPT we determine the NLO corrections to the LECs and their effect on the\ntaste splitting. Here the NLO partition function can be written as the leading\norder one with renormalized couplings, thus preserving the equivalence to\nstaggered chiral random matrix theory at NLO for any number of flavors N_f. In\nWChPT this relation only appears to hold for SU(2)."
    },
    {
        "anchor": "Neutron Electric Dipole Moments with Clover Fermions: We present preliminary results for the contributions to the neutron EDM\narising from the QCD $\\theta$-term, the Weinberg three-gluon and the quark\nchromo-EDM operators from our ongoing lattice calculations using clover valence\nquarks on the MILC HISQ lattices. We use the gradient-flow technique to smooth\nthe lattices and renormalize the gluonic operators, and use the Schwinger\nsource method to incorporate the quark chromo-EDM interactions in the quark\npropagator. For the QCD $\\theta$-term and the Weinberg three-gluon operator, we\nreport results in the gradient-flow scheme from 8 ensembles at four lattice\nspacings and three pion masses, including 2 physical pion mass ensembles. For\nthe quark chromo-EDM, unrenormalized results are presented at two lattice\nspacings, $a=0.12$ and $0.09$ fm, and two pion masses, $M_\\pi = 310$ MeV and\n$220$ MeV.",
        "positive": "The B*Bpi Coupling in the Static Limit: We study an accurate method for the lattice calculation of the B*Bpi Coupling\nin the static limit, paying particular attention to excited state\ncontamination. As this coupling is a parameter of the heavy meson chiral\nLagrangian, it is useful for constraining the chiral behaviour of various\nobservables in B-physics. We present a precise study of the continuum limit in\nthe quenched approximation and preliminary results with 2 flavours of improved\nWilson quarks (using CLS lattices) for pion masses down to around 250 MeV. With\ndynamical quarks both the lattice spacing and the light quark mass dependences\nare found to be very weak. We can quote g = 0.51(2) for the continuum value in\nthe chiral limit, where the error will be reduced when a more complete analysis\nhas been performed."
    },
    {
        "anchor": "On Heteropolymer Shape Dynamics: We investigate the time evolution of the heteropolymer model introduced by\nIori, Marinari and Parisi to describe some of the features of protein folding\nmechanisms. We study how the (folded) shape of the chain evolves in time. We\nfind that for short times the mean square distance (squared) between chain\nconfigurations evolves according to a power law, $D \\sim t ^\\nu$. We discuss\nthe influence of the quenched disorder (represented by the randomness of the\ncoupling constants in the Lennard-Jones potential) on value of the critical\nexponent. We find that $\\nu$ decreases from $\\frac{2}{3}$ to $\\frac{1}{2}$ when\nthe strength of the quenched disorder increases.",
        "positive": "Two-particle multichannel systems in a finite volume with arbitrary spin: The quantization condition for two-particle systems with arbitrary number of\ntwo-body open coupled channels, spin, momentum, and masses in a finite volume\nwith either periodic or twisted boundary conditions is presented. Although\nemphasis is placed in cubic volumes, the result holds for asymmetric volumes.\nThe result is relativistic, holds for all momenta below the three- and\nfour-particle thresholds, and is exact up to exponential volume corrections\nthat are governed by L/r, where L is the spatial extent of the volume and r is\nthe range of the interactions between the particles. For hadronic systems the\nrange of the interaction is set by the inverse of the pion mass, m_pi, and as a\nresult the formalism presented is suitable for m_pi L >> 1. The condition\npresented is in agreement with all previous studies of two-body systems in a\nfinite volume. Implications of the formalism for the studies of multichannel\nbaryon-baryon systems are discussed."
    },
    {
        "anchor": "Exploring the epsilon regime with twisted mass fermions: In this proceeding contribution we report on a first study in order to\nexplore the so called epsilon regime with Wilson twisted mass (Wtm) fermions.\nTo show the potential of this approach we give a preliminary determination of\nthe chiral condensate.",
        "positive": "Finite size scaling and triviality of \u03c6^4 theory on an antiperiodic\n  torus: Worm methods to simulate the Ising model in the Aizenman random current\nrepresentation including a low noise estimator for the connected four point\nfunction are extended to allow for antiperiodic boundary conditions. In this\nsetup several finite size renormalization schemes are formulated and studied\nwith regard to the triviality of \\phi^4 theory in four dimensions. With\nantiperiodicity eliminating the zero momentum Fourier mode a closer agreement\nwith perturbation theory is found compared to the periodic torus."
    },
    {
        "anchor": "Landau Gauge Gluon and Ghost Propagators from Lattice QCD: We report on recent numerical computations of the Landau gauge gluon and\nghost propagators as well as of the ghost-gluon vertex function in pure SU(3)\nYang-Mills theory and in full QCD on the lattice. Special emphasis is paid to\nthe low momentum region. In particular, we present new data for the gluon\npropagator at momenta below 300 MeV. We also discuss different systematic\neffects as there are finite-size, lattice discretization and Gribov copy but\nalso unquenching effects. A MOM-scheme running coupling \\alpha_s(q^2) based on\nthe ghost-gluon vertex is calculated and found to decrease for momenta below\n550 MeV, even though the renormalization constant of the vertex deviates only\nweakly from being constant.",
        "positive": "Calculation of the pion electromagnetic form factor from lattice QCD: We present a lattice calculation of the vector form factor of the pion for\ntwo flavours of non-perturbatively O(a) improved Wilson fermions. For the\nmeasurements we utilise the CLS ensembles which include various lattice\nspacings and pion masses down to about 250 MeV. To obtain a fine momentum\nresolution near zero momentum transfer (q^2) partially twisted boundary\nconditions are employed using several twist angles. Due to the fine resolution\naround q^2=0 we are able to determine the slope of the form factor and, in\nturn, extract the charge radius of the pion without any model dependence. The\nresults for the form factor and the charge radius are then compared to chiral\nperturbation theory and phenomenological models which are used to extrapolate\nthe results to the physical point."
    },
    {
        "anchor": "Spatial string tension revisited: The spatial string tension, a classic non-perturbative probe for the\nconvergence of the weak-coupling expansion at high temperatures, can be\ndetermined in full QCD as well as in a dimensionally reduced effective theory.\nComparing both approaches, we find surprisingly good agreement almost down to\nthe critical temperature of the deconfinement phase transition.",
        "positive": "Further extensions of the high-temperature expansions for the\n  two-dimensional classical XY model on the triangular and the square lattices: The high-temperature expansions for the spin-spin correlation function of the\ntwo-dimensional classical XY (planar rotator) model are extended by two terms,\nfrom order 24 through order 26, in the case of the square lattice, and by five\nterms, from order 15 through order 20, in the case of the triangular lattice.\nThe data are analyzed to improve the current estimates of the critical\nparameters of the models."
    },
    {
        "anchor": "Pion loops in quenched Quantum Chromodynamics: We calculate the divergences of the generating functional of quenched Chiral\nPerturbation Theory to one loop for a generic number of flavours. The flavour\nnumber dependence of our result enlightens the mechanism of quark loop\ncancellation in the quenched effective theory for any Green function or S\nmatrix element. We also apply our results to $\\pi \\pi$ scattering and evaluate\nthe coefficient of the chiral log in the S-wave scattering lengths for the\nquenched case.",
        "positive": "Perturbative results for two and three particle threshold energies in\n  finite volume: We calculate the energy of the state closest to threshold for two and three\nidentical, spinless particles confined to a cubic spatial volume with periodic\nboundary conditions and with zero total momentum in the finite-volume frame.\nThe calculation is performed in relativistic quantum field theory with\nparticles coupled via a $\\lambda \\phi^4$ interaction, and we work through order\n$\\lambda^3$. The energy shifts begin at ${\\cal O}(1/L^3)$, and we keep\nsubleading terms proportional to $1/L^4$, $1/L^5$ and $1/L^6$. These terms\nallow a non-trivial check of the results obtained from quantization conditions\nthat hold for arbitrary interactions, namely that of L\\\"uscher for two\nparticles and our recently developed formalism for three particles. We also\ncompare to previously obtained results based on non-relativistic quantum\nmechanics."
    },
    {
        "anchor": "Confinement versus color superconductivity: a lattice investigation: High density YM-theory is addressed by means of an effective theory where a\nHiggs type field corresponds to the diquark order parameter. The effective\nHiggs theory mimics the Cooper instability at the Fermi surface. After Landau\ngauge fixing, the theory possesses a global color degree of freedom. Color\nsuperconductivity corresponds to a spontaneous breakdown of the residual global\ncolor symmetry. Numerical simulations illustrate this mechanism of\nspontaneously broken global color for the case of the standard electro-weak\nphase transition and for the case of the transition between the confinement and\nthe Higgs phase, respectively. The latter transition is relevant for the study\nof diquark condensation.",
        "positive": "QCD Thermodynamics with an Improved Lattice Action: We have investigated QCD with two flavors of degenerate fermions using a\nSymanzik-improved lattice action for both the gauge and fermion actions. Our\nstudy focuses on the deconfinement transition on an $N_t=4$ lattice. Having\nlocated the thermal transition, we performed zero temperature simulations\nnearby in order to compute hadronic masses and the static quark potential. We\nfind that the present action reduces lattice artifacts present in\nthermodynamics with the standard Wilson (gauge and fermion) actions. However,\nit does not bring studies with Wilson-type quarks to the same level as those\nusing the Kogut--Susskind formulation."
    },
    {
        "anchor": "Reply to \"Comment on 'Lattice Gluon and Ghost Propagators, and the\n  Strong Coupling in Pure SU(3) Yang-Mills Theory: Finite Lattice Spacing and\n  Volume Effects' \": The quenched gluon and ghost propagator data published in [1] is reanalysed\nfollowing the suggestion of [2] to resolve the differences between the infrared\ndata of the simulations. Our results confirms that the procedure works well\neither for the gluon or for the ghost propagator but not for both propagators\nsimultaneously as the observed deviations in the data follow opposite patterns.\nDefinitive conclusions require improving the determination of the (ratios) of\nlattice spacings. A simple procedure for the relative calibration of the\nlattice spacing in lattice simulations is suggested.",
        "positive": "Evolutionary Algorithms Applied to Landau-Gauge Fixing: Current algorithms used to put a lattice gauge configuration into Landau\ngauge either suffer from the problem of critical slowing-down or involve an\nadditional computational expense to overcome it. Evolutionary Algorithms (EAs),\nwhich have been widely applied to other global optimisation problems, may be of\nuse in gauge fixing. Also, being global, they should not suffer from critical\nslowing-down as do local gradient based algorithms. We apply EA's and also a\nSteepest Descent (SD) based method to the problem of Landau Gauge Fixing and\ncompare their performance."
    },
    {
        "anchor": "The epsilon regime with twisted mass Wilson fermions: We investigate the leading lattice spacing effects in mesonic two-point\ncorrelators computed with twisted mass Wilson fermions in the epsilon-regime.\nBy generalizing the procedure already introduced for the untwisted Wilson\nchiral effective theory, we extend the continuum chiral epsilon expansion to\ntwisted mass WChPT. We define different regimes, depending on the relative\npower counting for the quark masses and the lattice spacing. We explicitly\ncompute, for arbitrary twist angle, the leading O(a^2) corrections appearing at\nNLO in the so-called GSM^* regime. As in untwisted WChPT, we find that in this\nsituation the impact of explicit chiral symmetry breaking due to lattice\nartefacts is strongly suppressed. Of particular interest is the case of maximal\ntwist, which corresponds to the setup usually adopted in lattice simulations\nwith twisted mass Wilson fermions. The formulae we obtain can be matched to\nlattice data to extract physical low energy couplings, and to estimate\nsystematic uncertainties coming from discretization errors.",
        "positive": "Determination of the Crumpling Fractal Dimension Via k-Space MCRG: Motivated by the successful application of MCRG in momentum space to $\\lambda\n\\phi^4_3$ we determine the critical exponents at the crumpling transition in\nfixed triangulated surfaces. The results are still tentative, but suggest that\n$-1.0\\ge \\eta \\ge -1.3$, pointing at a value for the fractal Hausdorff\ndimension at the crumpling transistion fixed point somewhere between 3 and 4."
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory around instantons: Numerical Stochastic Perturbation Theory (NSPT) has over the years proved to\nbe a valuable tool, in particular being able to reach unprecedented orders for\nLattice Gauge Theories, whose perturbative expansions are notoriously\ncumbersome. One of the key features of the method is the possibility to expand\naround non-trivial vacua. While this idea has been around for a while, and it\nhas been implemented in the case of the (non-trivial) background of the\nSchr\\\"odinger functional, NSPT expansions around instantons have not yet been\nfully worked out. Here we present computations for the double well potential in\nquantum mechanics. We compute a few orders of the expansion of the ground-state\nenergy splitting in the one-instanton sector. We discuss how (already) known\ntwo-loop results are reproduced and present the current status of higher-order\ncomputations.",
        "positive": "A nested Krylov subspace method to compute the sign function of large\n  complex matrices: We present an acceleration of the well-established Krylov-Ritz methods to\ncompute the sign function of large complex matrices, as needed in lattice QCD\nsimulations involving the overlap Dirac operator at both zero and nonzero\nbaryon density. Krylov-Ritz methods approximate the sign function using a\nprojection on a Krylov subspace. To achieve a high accuracy this subspace must\nbe taken quite large, which makes the method too costly. The new idea is to\nmake a further projection on an even smaller, nested Krylov subspace. If\nadditionally an intermediate preconditioning step is applied, this projection\ncan be performed without affecting the accuracy of the approximation, and a\nsubstantial gain in efficiency is achieved for both Hermitian and non-Hermitian\nmatrices. The numerical efficiency of the method is demonstrated on lattice\nconfigurations of sizes ranging from 4^4 to 10^4, and the new results are\ncompared with those obtained with rational approximation methods."
    },
    {
        "anchor": "Two- and three-particle scattering in the (1+1)-dimensional O(3)\n  non-linear sigma model: We study two- and three-particle scattering in the O(3) non-linear sigma\nmodel in 1+1 dimensions, focusing on the isospin-1 and isospin-2 channels for\ntwo particles, and the isospin-3 channel for three. We perform numerical\nsimulations for four values of the physical volume, each at three lattice\nspacings, using a three-cluster generalization of the cluster update algorithm,\nand directly extrapolate the determined finite-volume energies to the continuum\nat fixed physical volume. Lattice results for two particles are then compared\nagainst exact predictions, obtained by combining analytic results for the\nscattering phase shifts and the (1+1)-dimensional two-particle formalism that\nrelates these to finite-volume energies. Analogous comparisons in the\nthree-particle sector are underway, making use of the three-particle\nrelativistic-field-theory finite-volume formalism.",
        "positive": "A lattice path integral for supersymmetric quantum mechanics: We report on a study of the supersymmetric anharmonic oscillator computed\nusing a euclidean lattice path integral. Our numerical work utilizes a Fourier\naccelerated hybrid Monte Carlo scheme to sample the path integral. Using this\nwe are able to measure massgaps and check Ward identities to a precision of\nbetter than one percent. We work with a non-standard lattice action which we\nshow has an {\\it exact} supersymmetry for arbitrary lattice spacing in the\nlimit of zero interaction coupling. For the interacting model we show that\nsupersymmetry is restored in the continuum limit without fine tuning. This is\ncontrasted with the situation in which a `standard' lattice action is employed.\nIn this case supersymmetry is not restored even in the limit of zero lattice\nspacing. Finally, we show how a minor modification of our action leads to an\n{\\it exact}, local lattice supersymmetry even in the presence of interaction."
    },
    {
        "anchor": "Topological Aspects of Fermions on a Honeycomb Lattice: We formulate a model of relativistic fermions moving in two Euclidean\ndimensions based on a tight-binding model of graphene. The eigenvalue spectrum\nof the resulting Dirac operator is solved numerically in smooth U(1) gauge\nfield backgrounds carrying an integer-valued topological charge Q, and it is\ndemonstrated that the resulting number of zero-eigenvalue modes is in accord\nwith the Atiyah-Singer index theorem applied to two continuum flavors. A\nbilinear but gauge non-invariant chirality operator appropriate for\ndistinguishing the topological zero modes is identified. When this operator is\nused to calculate Q, it is found that the maximum topological charge capable of\nbeing measured in this fashion scales with the perimeter of the lattice. Some\nconcluding remarks compare these results to what is known for staggered lattice\nfermions.",
        "positive": "Four-dimensional graphene and chiral fermions: Motivated by the description of the graphene electronic structure in terms of\nthe relativistic Dirac equation, a generalization to four dimensions yields a\nstrictly local fermion action describing two species and possessing an exact\nchiral symmetry. This is the minimum number of species required by the well\nknown ``no-go'' theorems."
    },
    {
        "anchor": "Precise determination of the strangeness magnetic moment of the nucleon: By combining the constraints of charge symmetry with new chiral extrapolation\ntechniques and recent low mass lattice QCD simulations of the individual quark\ncontributions to the magnetic moments of the nucleon octet, we obtain a precise\ndetermination of the strange magnetic moment of the proton. The result, namely\nG_M^s = -0.046 +/- 0.019 mu_N, is consistent with the latest experimental\nmeasurements but an order of magnitude more precise. This poses a tremendous\nchallenge for future experiments.",
        "positive": "The screening length in hot QCD: We discuss the temperature dependence of the screening lengths in quenched\nand full QCD using the non-perturbative lattice approach. We analyze the\ntemperature dependence of distances which are defined as moments of quark\nantiquark free energies. These distance scales are supposed to describe the\ngeometric size of partonic clouds which screen static charges in a medium and\ncharacterize distances beyond which the quark antiquark free energy is to large\nextent dominated by medium effects. At asymptotic high temperatures these\nmoments can be related to the inverse Debye mass. In our numeric analysis we\nfind that these moments drop rapidly in the vicinity of the phase transition\nand indicate distances which are about twice as large as the inverse Debye mass\nfound in earlier studies. Our analysis supports recent findings that indicate\nthat $J/\\psi$ will show significant medium modifications only at temperatures\nwell above $T_c$."
    },
    {
        "anchor": "Density of observables from local derivatives: We derive a formula to calculate the local change to the log of any density\nof states for smooth real observables. Using this in Monte-Carlo simulations,\nwe are able to calculate the expectation value of the observable with a\nprecision often better than standard sampling. The method can be applied to\npreviously generated configurations, as long as the analysis uses the same\naction used to generate the configurations. We show that for observables such\nas Wilson line correlators, errors are reduced by up to 4 times.",
        "positive": "Monte Carlo study of glueball masses in the Hamiltonian limit of SU(3)\n  lattice gauge theory: Using Standard Euclidean Monte Carlo techniques, we discuss in detail the\nextraction of the glueball masses of 4-dimensional SU(3) lattice gauge theory\nin the Hamiltonian limit, where the temporal lattice spacing is zero. By taking\ninto account the renormalization of both the anisotropy and the Euclidean\ncoupling, we calculate the string tension and masses of the scalar, axial\nvector and tensor states using standard Wilson action on increasingly\nanisotropic lattices, and make an extrapolation to the Hamiltonian limit. The\nresults are compared with estimates from various other Hamiltonian and\nEuclidean studies. We find that more accurate determination of the glueball\nmasses and the mass ratios has been achieved and the results are a significant\nimprovement upon previous Hamiltonian estimates. The continuum predictions are\nthen found by extrapolation of results obtained from smallest values of spatial\nlattice spacing. For the lightest scalar, tensor and axial vector states we\nobtain masses of $m_{0^{++}}=1654 \\pm 83$ MeV, $m_{2^{++}}=2272\\pm 115$ MeV and\n$m_{1^{+-}}=2940\\pm 165$ MeV, respectively. These are consistent with the\nestimates obtained in the previous studies in the Euclidean limit. The\nconsistency is a clear evidence of universality between Euclidean and\nHamiltonian formulations. From the accuracy of our estimates, we conclude that\nthe standard Euclidean Monte Carlo method is a reliable technique for obtaining\nresults in the Hamiltonian version of the theory, just as in Euclidean case."
    },
    {
        "anchor": "Non-perturbative results for the coefficients b_m and b_a-b_p in O(a)\n  improved lattice QCD: We determine the improvement coefficients b_m and b_a-bp in quenched lattice\nQCD for a range of beta-values, which is relevant for current large scale\nsimulations. At fixed beta, the results are rather sensitive to the precise\nchoices of parameters. We therefore impose improvement conditions at constant\nrenormalized parameters, and the coefficients are then obtained as smooth\nfunctions of g_0^2. Other improvement conditions yield a different functional\ndependence, but the difference between the coefficients vanishes with a rate\nproportional to the lattice spacing. We verify this theoretical expectation in\na few examples and are therefore confident that O(a) improvement is achieved\nfor physical quantities. As a byproduct of our analysis we also obtain the\nfinite renormalization constant which relates the subtracted bare quark mass to\nthe bare PCAC mass.",
        "positive": "Lattice calculation of the leading strange quark-connected contribution\n  to the muon $g-2$: We present results for the leading hadronic contribution to the muon\nanomalous magnetic moment due to strange quark-connected vacuum polarisation\neffects. Simulations were performed using RBC--UKQCD's $N_f=2+1$ domain wall\nfermion ensembles with physical light sea quark masses at two lattice spacings.\nWe consider a large number of analysis scenarios in order to obtain solid\nestimates for residual systematic effects. Our final result in the continuum\nlimit is $a_\\mu^{(2)\\,{\\rm\nhad},\\,s}=53.1(9)\\left(^{+1}_{-3}\\right)\\times10^{-10}$."
    },
    {
        "anchor": "Low temperature limit of lattice QCD: We study the low temperature limit of lattice QCD by using a reduction\nformula for a fermion determinant. The reduction formula, which is useful in\nfinite density lattice QCD simulations, contains a reduced matrix defined as\nthe product of $N_t$ block-matrices. It is shown that eigenvalues of the\nreduced matrix follows a scaling law with regard to the temporal lattice size\n$N_t$. The $N_t$ scaling law leads to two types of expressions of the fermion\ndeterminant in the low temperature limit; one is for small quark chemical\npotentials, and the other is for larger quark chemical potentials.",
        "positive": "A novel improved action for SU(3) lattice gauge theory: SU(3) lattice gauge theory is studied by means of an improved action where a\n$2 \\times 2$ Wilson loop is supplemented to the standard plaquette term. By\ncontrast to earlier studies using a tree level improvement, the prefactor of\nthe $2 \\times 2$ Wilson term is determined by minimizing the breaking of\nrotational symmetry detected from the static quark-antiquark potential. On\ncoarse lattices, the novel action is superior to the Iwasaki action and\ncomparable with DBW2 action. The scaling behavior of the novel action is\nstudied by using the static quark potential and the ratio of the deconfinement\ntemperature and the string tension."
    },
    {
        "anchor": "Induced QCD I: Theory: We explore an alternative discretization of continuum SU(N_c) Yang-Mills\ntheory on a Euclidean spacetime lattice, originally introduced by Budzcies and\nZirnbauer. In this discretization the self-interactions of the gauge field are\ninduced by a path integral over N_b auxiliary boson fields, which are coupled\nlinearly to the gauge field. The main progress compared to earlier approaches\nis that N_b can be as small as N_c. In the present paper we (i) extend the\nproof that the continuum limit of the new discretization reproduces Yang-Mills\ntheory in two dimensions from gauge group U(N_c) to SU(N_c), (ii) derive\nrefined bounds on N_b for non-integer values, and (iii) perform a perturbative\ncalculation to match the bare parameter of the induced gauge theory to the\nstandard lattice coupling. In follow-up papers we will present numerical\nevidence in support of the conjecture that the induced gauge theory reproduces\nYang-Mills theory also in three and four dimensions, and explore the\npossibility to integrate out the gauge fields to arrive at a dual formulation\nof lattice QCD.",
        "positive": "The Negativity of the Overlap-Based Topological Charge Density\n  Correlator in Pure-Glue QCD and the Non-Integrable Nature of its Contact Part: We calculate the lattice two-point function of topological charge density in\npure-glue QCD using the discretization of the operator based on the overlap\nDirac matrix. Utilizing data at three lattice spacings it is shown that the\ncontinuum limit of the correlator complies with the requirement of\nnon-positivity at non-zero distances. For our choice of the overlap operator\nand the Iwasaki gauge action we find that the size of the positive core is ~2a\n(with a being the lattice spacing) sufficiently close to the continuum limit.\nThis result confirms that the overlap-based topological charge density is a\nvalid local operator over realistic backgrounds contributing to the QCD path\nintegral, and is important for the consistency of recent results indicating the\nexistence of a low-dimensional global brane-like topological structure in the\nQCD vacuum. We also confirm the divergent short-distance behavior of the\ncorrelator, and the non-integrable nature of the associated contact part."
    },
    {
        "anchor": "A Note on Reflection Positivity and the Umezawa-Kamefuchi-Kallen-Lehmann\n  Representation of Two Point Correlation Functions: It will be proved that a model of lattice field theories which satisfies (A1)\nHermiticity, (A2) translational invariance, (A3) reflection positivity, and\n(A4) polynomial boundedness of correlations, permits the\nUmezaa-Kamefuchi-Kallen-Lehmann representation of two point correlation\nfunctions with positive spectral density function. Then, we will also argue\nthat positivity of spectral density functions is necessary for a lattice theory\nto satisfy conditions (A1) - (A4). As an example, a lattice overlap scalar\nboson model will be discussed. We will find that the overlap scalar boson\nviolates the reflection positivity.",
        "positive": "Critical $1$- and $2$-point spin correlations for the $O(2)$ model in\n  $3d$ bounded domains: We study the critical properties of the $3d$ $O(2)$ universality class in\nbounded domains through Monte Carlo simulations of the clock model. We use an\nimproved version of the latter, chosen to minimize finite-size corrections at\ncriticality, with 8 orientations of the spins and in the presence of vacancies.\nThe domain chosen for the simulations is the slab configuration with fixed\nspins at the boundaries. We obtain the universal critical magnetization profile\nand two-point correlations, which favorably compare with the predictions of the\ncritical geometry approach based on the Yamabe equation. The main result is\nthat the correlations, once the dimensionful contributions are factored out\nwith the critical magnetization profile, are shown to only depend on the\ndistance between the points computed using a metric found solving the\nfractional Yamabe equation. The quantitative comparison with the corresponding\nresults for the Ising model at criticality is shown and discussed. Moreover,\nfrom the magnetization profiles the critical exponent $\\eta$ is extracted and\nfound to be in reasonable agreement with up-to-date results."
    },
    {
        "anchor": "Exact Chiral Invariance at Finite Density on Lattice: A new lattice action is proposed for the overlap Dirac matrix with nonzero\nchemical potential. It is shown to preserve the full chiral invariance for all\nvalues of lattice spacing exactly. It is further demonstrated to arise in the\ndomain wall formalism by coupling the chemical potential count only to the\nphysically relevant wall modes.",
        "positive": "A Lattice Test of 1/N_c Baryon Mass Relations: 1/N_c baryon mass relations are compared with lattice simulations of baryon\nmasses using different values of the light-quark masses, and hence different\nvalues of SU(3) flavor-symmetry breaking. The lattice data clearly display both\nthe 1/N_c and SU(3) flavor-symmetry breaking hierarchies. The validity of 1/N_c\nbaryon mass relations derived without assuming approximate SU(3)\nflavor-symmetry also can be tested by lattice data at very large values of the\nstrange quark mass. The 1/N_c expansion constrains the form of discretization\neffects; these are suppressed by powers of 1/N_c by taking suitable\ncombinations of masses. This 1/N_c scaling is explicitly demonstrated in the\npresent work."
    },
    {
        "anchor": "Differential decay rate of $B \\to \u03c0l \u03bd$ semileptonic decay with\n  lattice NRQCD: We present a lattice QCD calculation of $B\\to \\pi l \\nu$ semileptonic decay\nform factors in the small pion recoil momentum region. The calculation is\nperformed on a quenched $16^3 \\times 48$ lattice at $\\beta=5.9$ with the NRQCD\naction including the full 1/M terms. The form factors $f_1(v\\cdot k_{\\pi})$ and\n$f_2(v\\cdot k_{\\pi})$ defined in the heavy quark effective theory for which the\nheavy quark scaling is manifest are adpoted, and we find that the 1/M\ncorrection to the scaling is small for the $B$ meson. The dependence of form\nfactors on the light quark mass and on the recoil energy is found to be mild,\nand we use a global fit of the form factors at various quark masses and recoil\nenergies to obtain model independent results for the physical differential\ndecay rate. We find that the $B^*$ pole contribution dominates the form factor\n$f^+(q^2)$ for small pion recoil energy, and obtain the differential decay rate\nintegrated over the kinematic region $q^2 >$ 18 GeV$^2$ to be $|V_{ub}|^2\n\\times (1.18 \\pm 0.37 \\pm 0.08 \\pm 0.31)$ psec$^{-1}$, where the first error is\nstatistical, the second is that from perturbative calculation, and the third is\nthe systematic error from finite lattice spacing and the chiral extrapolation.\nWe also discuss the systematic errors in the soft pion limit for\n$f^0(q^2_{max})$ in the present simulation.",
        "positive": "The B -> pi l nu form factor from unquenched lattice QCD with\n  domain-wall light quarks and relativistic b-quarks: We report on a lattice-QCD calculation of the B to pi l nu form factor with\ndomain-wall light quarks and relativistic b-quarks using the 2 + 1 flavor\ndomain-wall fermion and Iwasaki gauge-field ensembles generated by the RBC and\nUKQCD Collaborations. We present initial results obtained from the coarser (a ~\n0.11 fm) 24^3 lattices and some of the finer (a ~ 0.086 fm) 32^3 lattices."
    },
    {
        "anchor": "Searching for the elusive critical endpoint at finite temperature and\n  isospin density: We consider 3-flavour lattice QCD with a finite chemical potential mu_I for\nisospin, close to the finite temperature transition from hadronic matter to a\nquark-gluon plasma. In this region one can argue that the position and probably\nthe nature of this transition mimic those at finite quark-number chemical\npotential mu. The quark mass is chosen to be close to the critical mass at zero\nchemical potentials. Since the Binder cumulants used to determine the nature of\nthis transition in HMD(R) simulations are very sensitive to the updating\nincrement dt, we have switched to the newer exact RHMC algorithm for our\nsimulations. Preliminary results indicate that there is no critical endpoint in\nthe small mu_I regime, at least none connected with the critical point at zero\nchemical potentials.",
        "positive": "Dynamical fermion mass generation at a tricritical point in strongly\n  coupled U(1) lattice gauge theory: Fermion mass generation in the strongly coupled U(1) lattice gauge theory\nwith fermion and scalar fields of equal charge is investigated by means of\nnumerical simulation with dynamical fermions. Chiral symmetry of this model is\nbroken by the gauge interaction and restored by the light scalar. We present\nevidence for the existence of a particular, tricritical point of the\ncorresponding phase boundary where the continuum limit might possibly be\nconstructed. It is of interest as a model for dynamical symmetry breaking and\nmass generation due to a strong gauge interaction. In addition to the massive\nand unconfined fermion F and Goldstone boson $\\pi$, a gauge ball of mass $m_S\n\\simeq 1/2 m_F$ and some other states are found. Tricritical exponents appear\nto be non-classical."
    },
    {
        "anchor": "Imprint of chiral symmetry restoration on the Polyakov loop and the\n  heavy quark free energy: The Polyakov loop expectation value $\\langle P\\rangle$ is an order parameter\nof the deconfinement transition in the heavy quark mass regime, whereas its\nsensitivity to the deconfinement of light, dynamical quarks is not apparent.\nFrom the perspective of an effective Lagrangian in the vicinity of the chiral\ntransition, the Polyakov loop, $P$, is an energy-like observable, and $\\langle\nP\\rangle$ should hence scale like the energy density. Using $N_f=2+1$ HISQ\nconfigurations at finite lattice spacing, we show that near the chiral\ntransition temperature, the scaling behavior of $\\langle P\\rangle$ and the\nheavy quark free energy $F_q$ is consistent with energy-like observables in the\n3-$d$, O($N$) universality class. We extend this analysis to other Polyakov\nloop observables, including the response of the heavy quark free energy, $F_q$,\nto the baryon chemical potential, which is expected to scale like a specific\nheat.",
        "positive": "The Chiral Phase Transition in three-flavor QCD from Lattice QCD: We analyze the pseudo-critical behavior of three-flavor QCD using highly\nimproved staggered quarks (HISQ) on lattices with temporal extent $N_\\tau =8$\nand for quark masses corresponding to a pseudoscalar Goldstone mass in the\nrange $80 ~ {\\rm MeV} ~ \\lesssim ~ m_\\pi ~ \\lesssim ~ 140 ~ {\\rm MeV}$. Our\nfindings are consistent with the occurrence of a second order chiral phase\ntransition at vanishing values of the quark masses. The chiral phase transition\ntemperature at this finite value of the lattice spacing is determined to be\n$T_c = 98_{-6}^{+3}~{\\rm MeV}$. A comparison with a corresponding analysis\nperformed in (2+1)-flavor QCD suggests that the continuum limit extrapolated\nchiral phase transition temperature in 3-flavor QCD will turn out to be below\n$90 ~ {\\rm MeV}$."
    },
    {
        "anchor": "A Lattice Evaluation of the Deep-Inelastic Structure Functions of the\n  Nucleon: The lower moments of the unpolarized and polarized deep-inelastic structure\nfunctions of the nucleon are calculated on the lattice. The calculation is done\nwith Wilson fermions and for three values of the hopping parameter $\\kappa$, so\nthat we can perform the extrapolation to the chiral limit. Particular emphasis\nis put on the renormalization of lattice operators. The renormalization\nconstants, which lead us from lattice to continuum operators, are computed\nperturbatively to one loop order as well as non-perturbatively.",
        "positive": "Determination of the spin-dependent potentials with the multi-level\n  algorithm: The spin-dependent corrections to the static interquark potential are\nrelevant to describing the fine and hyper-fine splittings of the heavy\nquarkonium spectra. We investigate these corrections in SU(3) lattice gauge\ntheory with the Polyakov loop correlation function as the quark source by\napplying the multi-level algorithm. We observe remarkably clean signals for the\nspin-dependent potentials up to intermediate distances."
    },
    {
        "anchor": "Calorons on the lattice - a new perspective: We discuss the manifestation of instanton and monopole solutions on a\nperiodic lattice at finite temperature and their relation to the infinite\nvolume analytic caloron solutions with asymptotic non-trivial Polyakov loops.\nAs a tool we use improved cooling and twisted boundary conditions. Typically we\nfind 2Q lumps for topological charge Q. These lumps are BPS monopoles.",
        "positive": "Nuclear Physics from lattice QCD at strong coupling: We study numerically the strong coupling limit of lattice QCD with one flavor\nof massless staggered quarks. We determine the complete phase diagram as a\nfunction of temperature and chemical potential, including a tricritical point.\nWe clarify the nature of the low temperature dense phase, which is strongly\nbound nuclear matter. This strong binding is explained by the nuclear\npotential, which we measure. Finally, we determine, from this first-principle\nlimiting case of QCD, the masses of atomic nuclei up to A=12 \"carbon\"."
    },
    {
        "anchor": "Few-body bound states and resonances in finite volume: Since the pioneering work of L\\\"uscher in the 1980s it is well known that\nconsidering quantum systems in finite volume, specifically, finite periodic\nboxes, can be used as a powerful computational tool to extract physical\nobservables. While this formalism has been worked out in great detail in the\ntwo-body sector, much effort is currently being invested into deriving\nanalogous relations for systems with more constituents. This work is relevant\nnot only for nuclear physics, where lattice methods are now able to calculate\nfew- and many-nucleon states, but also for other fields such as simulations of\ncold atoms. This article discusses recent progress regarding the extraction of\nfew-body bound-state and resonance properties from finite-volume calculations\nof systems with an arbitrary number of constituents.",
        "positive": "Improving efficiency of the path optimization method for a gauge theory: We investigate efficiency of a gauge-covariant neural network and an\napproximation of the Jacobian in optimizing the complexified integration path\ntoward evading the sign problem in lattice field theories. For the construction\nof the complexified integration path, we employ the path optimization method.\nThe $2$-dimensional $\\text{U}(1)$ gauge theory with the complex gauge coupling\nconstant is used as a laboratory to evaluate the efficiency. It is found that\nthe gauge-covariant neural network, which is composed of the Stout-like\nsmearing, can enhance the average phase factor, as the gauge-invariant input\ndoes. For the approximation of the Jacobian, we test the most drastic case in\nwhich we perfectly drop the Jacobian during the learning process. It reduces\nthe numerical cost of the Jacobian calculation from ${\\cal O}(N^3)$ to ${\\cal\nO}(1)$, where $N$ means the number of degrees of freedom of the theory. The\npath optimization using this Jacobian approximation still enhances the average\nphase factor at expense of a slight increase of the statistical error."
    },
    {
        "anchor": "Phase diagram of Regge quantum gravity coupled to SU(2) gauge theory: We analyze Regge quantum gravity coupled to SU(2) gauge theory on $4^3\\times\n2$, $6^{3}\\times 4$ and $8^{3}\\times 4$ simplicial lattices. It turns out that\nthe window of the well-defined phase of the gravity sector where geometrical\nexpectation values are stable extends to negative gravitational couplings as\nwell as to gauge couplings across the deconfinement phase transition. We study\nthe string tension from Polyakov loops, compare with the $\\beta$-function of\npure gauge theory and conclude that a physical limit through scaling is\npossible.",
        "positive": "What's up with IR gluon and ghost propagators in Landau gauge? A\n  puzzling answer from huge lattices: Several analytic approaches predict for SU(N_c) Yang-Mills theories in Landau\ngauge an enhanced ghost propagator G(p^2) and a suppressed gluon propagator\nD(p^2) at small momenta. This prediction applies to two, three and four\nspace-time dimensions. Moreover, the gluon propagator is predicted to be null\nat p = 0. Numerical studies by several groups indeed support an enhanced ghost\npropagator when compared to the tree-level behavior $1/p^2$ and a finite\ninfrared gluon propagator. However, the agreement between analytic and\nnumerical studies is only at the qualitative level in three and in four\ndimensions. In particular, the infrared exponent of the ghost propagator seems\nto be smaller than the one predicted analytically and the gluon propagator\nseems to display a (finite) nonzero value at zero momentum. It has been argued\nthat this discrepancy might go away once simulations are done on much larger\nlattice sizes than the ones used up to now. Here we present data in three and\nfour space-time dimensions using huge lattices in the scaling region, i.e. up\nto 320^3 at beta = 3.0 and up to 128^4 at beta = 2.2, corresponding to V\n\\approx (85 fm)^3 and V \\approx (27 fm)^4. Simulations have been done on the\nIBM supercomputer at the University of Sao Paulo"
    },
    {
        "anchor": "Phase Transition Properties of 3D Potts Models: Using multicanonical Metropolis simulations we estimate phase transition\nproperties of 3D Potts models for q=4 to 10: The transition temperatures,\nlatent heats, entropy gaps, normalized entropies at the disordered and ordered\nendpoints, interfacial tensions, and spinodal endpoints.",
        "positive": "Gauge generation and dissemination in OpenLat: In this contribution we report the status and plans of the open lattice\ninitiative to generate and share new gauge ensembles using the stabilised\nWilson fermion framework. The production strategy is presented in terms of a\nthree stage plan alongside summaries of the data management as well as access\npolicies. Current progress in completing the first stage of generating\nensembles at four lattice spacings at the flavor symmetric point is given."
    },
    {
        "anchor": "Meron Pairs and Fermion Zero Modes: Merons, conjectured as a semiclassical mechanism for color confinement in\nQCD, have been described analytically by either infinite action configurations\nor an Ansatz with discontinuous action. We construct a smooth, finite action,\nstationary lattice solution corresponding to a meron pair. We also derive an\nanalytical solution for the zero mode of the meron pair Ansatz, show that it\nhas the qualitative behavior of the exact zero mode of the lattice solution,\nand propose the use of zero modes to identify meron gauge field configurations\nin stochastic evaluations of the lattice QCD path integral.",
        "positive": "Hubbard Model with L\u00fcscher fermions: We study the basic features of the two-dimensional quantum Hubbard Model at\nhalf-filling by means of the L\\\"uscher algorithm and the algorithm based on\ndirect update of the determinant of the fermionic matrix. We implement the\nL\\\"uscher idea employing the transfer matrix formalism which allows to\nformulate the problem on the lattice in $(2+1)$ dimensions. We discuss the\nnumerical complexity of the L\\\"uscher technique, systematic errors introduced\nby polynomial approximation and introduce some improvements which reduce long\nautocorrelations. In particular we show that preconditioning of the fermionic\nmatrix speeds up the algorithm and extends the available range of parameters.\nWe investigate the magnetic and the one-particle properties of the Hubbard\nModel at half-filling and show that they are in qualitative agreement with the\nexisting Monte Carlo data and the mean-field predictions."
    },
    {
        "anchor": "Update on the improved lattice calculation of direct CP-violation in K\n  decays: We discuss the status of the RBC & UKQCD collaboration's lattice\ndetermination of $\\epsilon'$, the measure of direct CP-violation in kaon\ndecays, focusing in particular on recent developments in statistical techniques\nfor estimating standard errors and goodness-of-fit metrics for large amounts of\ndata that have correlations both in the temporal coordinate and also in\nmolecular dynamics time. A key result is the formulation of a technique for\ndetermining the null distribution of a fit using a bootstrap method that is\nfree from the usual assumptions of independence, large-$n$ and/or normal data,\nthat can for instance be applied to compute p-values even for uncorrelated\nfits.",
        "positive": "Antisymmetric and other subleading corrections to scaling in the local\n  potential approximation: For systems in the universality class of the three-dimensional Ising model we\ncompute the critical exponents in the local potential approximation (LPA), that\nis, in the framework of the Wegner-Houghton equation. We are mostly interested\nin antisymmetric corrections to scaling, which are relatively poorly studied.\nWe find the exponent for the leading antisymmetric correction to scaling\n$\\omega_A \\approx 1.691$ in the LPA. This high value implies that such\ncorrections cannot explain asymmetries observed in some Monte Carlo\nsimulations."
    },
    {
        "anchor": "Critical endline of the finite temperature phase transition for 2+1\n  flavor QCD around the SU(3)-flavor symmetric point: We investigate the critical endline of the finite temperature phase\ntransition of QCD around the SU(3)-flavor symmetric point at zero chemical\npotential. We employ the renormalization-group improved Iwasaki gauge action\nand non-perturbatively $O(a)$-improved Wilson-clover fermion action. The\ncritical endline is determined by using the intersection point of kurtosis,\nemploying the multi-parameter, multi-ensemble reweighting method to calculate\nobservables off the SU(3)-symmetric point, at the temporal size $N_{\\rm T}$=6\nand lattice spacing as low as $a \\approx 0.19$ fm. We confirm that the slope of\nthe critical endline takes the value of $-2$, and find that the second\nderivative is positive, at the SU(3)-flavor symmetric point on the Columbia\nplot parametrized with the strange quark mass $m_s$ and degenerated up-down\nquark mass $m_{\\rm l}$.",
        "positive": "QCD dynamics in a constant chromomagnetic field: We investigate the phase transition in full QCD with two flavors of staggered\nfermions in presence of a constant abelian chromomagnetic field. We find that\nthe critical temperature depends on the strength of the chromomagnetic field\nand that the deconfined phase extends to very low temperatures for strong\nenough fields. As in the case of zero external field, a single transition is\ndetected, within statistical uncertainties, where both deconfinement and chiral\nsymmetry restoration take place. We also find that the chiral condensate\nincreases with the strength of the chromomagnetic field."
    },
    {
        "anchor": "Non-Perturbative Simulations of Quantum Field Theories using Complex\n  Langevin Dynamics: Non-perturbative formulations of field theories are essential to capture\nintriguing physical phenomena, including confinement in QCD, spontaneous\nsupersymmetry breaking, and dynamical compactification in superstrings. Lattice\nregularization provides a robust framework to study these non-perturbative\nfeatures through Euclidean path integrals. Conventionally, path integrals are\nnumerically evaluated using Monte Carlo methods, where the Boltzmann factor is\ninterpreted as a probability weight. However, complex actions in various\nphysical systems render the Boltzmann factor complex, leading to the sign\nproblem. The complex Langevin method overcomes the sign problem and can be used\nto evaluate complex integrals. This thesis employs the complex Langevin method\nto investigate various non-perturbative aspects of field-theoretic systems with\ncomplex actions. We probe the possibility of spontaneous supersymmetry breaking\nin the simplest realizations of supersymmetric field theories. These systems\ngenerally have complex actions arising from a complex determinant of the\nfermion operator. We studied various interesting classes of complex potentials,\nincluding those exhibiting PT-symmetry. Another exciting aspect explored is the\ndynamical compactification of extra dimensions in superstring theory. The IKKT\nmatrix model, in the large-N limit, is a conjectured formulation for the 10D\ntype IIB string theory. We employ the complex Langevin method to investigate\nthe Euclidean version of this matrix model, which has an inherent complex\nPfaffian, to probe the spontaneous breaking of SO(10) symmetry. The\ninvestigations performed in this thesis suggest that the complex Langevin\nmethod can successfully simulate non-perturbative aspects of quantum field\ntheories by taming the associated sign problem.",
        "positive": "Critical point in the QCD phase diagram for extremely strong background\n  magnetic fields: Lattice simulations have demonstrated that a background (electro)magnetic\nfield reduces the chiral/deconfinement transition temperature of quantum\nchromodynamics for eB < 1 GeV^2. On the level of observables, this reduction\nmanifests itself in an enhancement of the Polyakov loop and in a suppression of\nthe light quark condensates (inverse magnetic catalysis) in the transition\nregion. In this paper, we report on lattice simulations of 1+1+1-flavor QCD at\nan unprecedentedly high value of the magnetic field eB = 3.25 GeV^2. Based on\nthe behavior of various observables, it is shown that even at this extremely\nstrong field, inverse magnetic catalysis prevails and the transition, albeit\nbecoming sharper, remains an analytic crossover. In addition, we develop an\nalgorithm to directly simulate the asymptotically strong magnetic field limit\nof QCD. We find strong evidence for a first-order deconfinement phase\ntransition in this limiting theory, implying the presence of a critical point\nin the QCD phase diagram. Based on the available lattice data, we estimate the\nlocation of the critical point."
    },
    {
        "anchor": "Quantum mean estimation for lattice field theory: We demonstrate the quantum mean estimation algorithm on Euclidean lattice\nfield theories. This shows a quadratic advantage over Monte Carlo methods which\npersists even in presence of a sign problem, and is insensitive to critical\nslowing down. The algorithm is used to compute $\\pi$ with and without a sign\nproblem, a toy U(1) gauge theory model, and the Ising model. The effect of\n$R_{Z}$-gate synthesis errors on a future fault-tolerant quantum computer is\ninvestigated.",
        "positive": "Lattice calculation of electromagnetic corrections to $K\\ell3$ decay: We describe a first-principles method to apply lattice QCD to compute the\norder $\\alpha_{\\mathrm{EM}}$ corrections to $K\\to\\pi\\ell\\nu_\\ell$ decay. This\nmethod formulates the calculation in infinite volume with the conventional\ninfinite-volume, continuum treatment of QED. Infinite volume reconstruction is\nused to replace the QCD components of the calculation with finite-volume\namplitudes which can be computed in Euclidean space using lattice QCD,\nintroducing finite-volume errors which vanish exponentially as the volume used\nin the QCD calculation is increased. This approach has also been described in\nan appendix to the recent paper: arXiv:2304.08026."
    },
    {
        "anchor": "Light quark masses in quenched QCD with exact chiral symmetry: The parameters in the pseudoscalar meson mass formula in quenched chiral\nperturbation theory to one-loop order are determined by quenched lattice QCD\nwith overlap Dirac operator, and from which the light quark masses are\ndetermined with the experimental inputs of pion and kaon masses, and the pion\ndecay constant. Our results are $ m_{u,d} = 5.3 \\pm 0.3 $ MeV, and $ m_s =\n115\\pm 8 $ MeV, in the $ \\bar{MS} $ scheme at scale $ \\mu = 2 $ GeV.",
        "positive": "Chiral Symmetry Restoration in Anisotropic QED(3): We present results from a Monte Carlo simulation of non-compact lattice QED\nin 3 dimensions in which an explicit anisotropy $\\kappa$ between $x$ and $y$\nhopping terms has been introduced into the action. Using a parameter set\ncorresponding to broken chiral symmetry in the isotropic limit $\\kappa=1$, we\nstudy the chiral condensate on $16^3$, $20^3$, and $24^3$ lattices as $\\kappa$\nis varied, and fit the data to an equation of state which incorporates\nanisotropic volume corrections. The value $\\kappa_c$ at which chiral symmetry\nispparently restored is strongly volume-dependent, suggesting that the\ntransition may be a crossover rather than a true phase transition. In addition\nwe present results on $16^3$ lattices for the scalar meson propagator, and for\nthe Landau gauge-fixed fermion propagator. The scalar mass approaches the pion\nmass at large $\\kappa$, consistent with chiral symmetry restoration, but the\nfermion remains massive at all values of $\\kappa$ studied, suggesting that\nstrong infra-red fluctuations persist into the chirally symmetric regime.\nImplications for models of high-$T_c$ superconductivity based on anisotropic\nQED$_3$ are discussed."
    },
    {
        "anchor": "Spin-Orbit Force from Lattice QCD: We present a first attempt to determine nucleon-nucleon potentials in the\nparity-odd sector, which appear in 1P1, 3P0, 3P1, 3P2-3F2 channels, in Nf=2\nlattice QCD simulations. These potentials are constructed from the\nNambu-Bethe-Salpeter wave functions for J^P=0^-, 1^- and 2^-, which correspond\nto A1^-, T1^- and T2^- + E^- representation of the cubic group, respectively.\nWe have found a large and attractive spin-orbit potential VLS(r) in the\nisospin-triplet channel, which is qualitatively consistent with the\nphenomenological determination from the experimental scattering phase shifts.\nThe potentials obtained from lattice QCD are used to calculate the scattering\nphase shifts in 1P1, 3P0, 3P1 and 3P2-3F2 channels. The strong attractive\nspin-orbit force and a weak repulsive central force in spin-triplet P-wave\nchannels lead to an attraction in the 3P2 channel, which is related to the\nP-wave neutron paring in neutron stars.",
        "positive": "Non-perturbative improvement of lattice QCD at large momenta: We propose a method to improve lattice operators composed of Wilson fermions\nwhich allows the removal of all corrections of $O(a)$, including those\nproportional to the quark mass. It requires off-shell improvement of quark\nfields and composite operators, which is achieved by studying the behaviour of\nquark and gluon correlation functions at large momenta."
    },
    {
        "anchor": "The Role of Vortex Strings in the Non-Compact Lattice Abelian Higgs\n  Model: The non-compact lattice version of the Abelian Higgs model is studied in\nterms of its topological excitations. The Villain form of the partition\nfunction is represented as a sum over world-sheets of gauge-invariant\n``vortex'' strings. The phase transition of the system is then related to the\ndensity of these excitations. Through Monte Carlo simulations the density of\nthe vortex sheets is shown to be a good order parameter for the system. The\nvortex density essentially vanishes in the Higgs phase, and the Coulomb phase\nconsists of a single vortex condensate.",
        "positive": "Lattice computation of the nucleon scalar quark contents at the physical\n  point: We present a QCD calculation of the $u$, $d$ and $s$ scalar quark contents of\nnucleons based on $47$ lattice ensembles with $N_f = 2+1$ dynamical sea quarks,\n$5$ lattice spacings down to $0.054\\,\\text{fm}$, lattice sizes up to\n$6\\,\\text{fm}$ and pion masses down to $120\\,\\text{MeV}$. Using the\nFeynman-Hellmann theorem, we obtain $f^N_{ud} = 0.0405(40)(35)$ and $f^N_s =\n0.113(45)(40)$, which translates into $\\sigma_{\\pi N}=38(3)(3)\\,\\text{MeV}$,\n$\\sigma_{sN}=105(41)(37)\\,\\text{MeV}$ and $y_N=0.20(8)(8)$ for the sigma terms\nand the related ratio, where the first errors are statistical and the second\nare systematic. Using isospin relations, we also compute the individual up and\ndown quark contents of the proton and neutron (results in the main text)."
    },
    {
        "anchor": "Worm Algorithm for CP(N-1) Model: The CP(N-1) model in 2D is an interesting toy model for 4D QCD as it\npossesses confinement, asymptotic freedom and a non-trivial vacuum structure.\nDue to the lower dimensionality and the absence of fermions, the computational\ncost for simulating 2D CP(N-1) on the lattice is much lower than that for\nsimulating 4D QCD. However, to our knowledge, no efficient algorithm for\nsimulating the lattice CP(N-1) model has been tested so far, which also works\nat finite density. To this end we propose a new type of worm algorithm which is\nappropriate to simulate the lattice CP(N-1) model in a dual, flux-variables\nbased representation, in which the introduction of a chemical potential does\nnot give rise to any complications. In addition to the usual worm moves where a\ndefect is just moved from one lattice site to the next, our algorithm\nadditionally allows for worm-type moves in the internal variable space of\nsingle links, which accelerates the Monte Carlo evolution. We use our algorithm\nto compare the two popular CP(N-1) lattice actions and exhibit marked\ndifferences in their approach to the continuum limit.",
        "positive": "A relativistic, model-independent, three-particle quantization condition: We present a generalization of Luescher's relation between the finite-volume\nspectrum and scattering amplitudes to the case of three particles. We consider\na relativistic scalar field theory in which the couplings are arbitrary aside\nfrom a Z2 symmetry that removes vertices with an odd number of particles. The\ntheory is assumed to have two-particle phase shifts that are bounded by \\pi/2\nin the regime of elastic scattering. We determine the spectrum of the\nfinite-volume theory from the poles in the odd-particle-number finite-volume\ncorrelator, which we analyze to all orders in perturbation theory. We show that\nit depends on the infinite-volume two-to-two K-matrix as well as a nonstandard\ninfinite-volume three-to-three K-matrix. A key feature of our result is the\nneed to subtract physical singularities in the three-to-three amplitude and\nthus deal with a divergence-free quantity. This allows our initial, formal\nresult to be truncated to a finite dimensional determinant equation. At\npresent, the relation of the three-to-three K-matrix to the corresponding\nscattering amplitude is not known, although previous results in the\nnon-relativistic limit suggest that such a relation exists."
    },
    {
        "anchor": "Green's Function Monte Carlo approach to SU(3) Yang-Mills theory in\n  (3+1)D: A 'forward walking' Green's Function Monte Carlo algorithm is used to obtain\nexpectation values for SU(3) lattice Yang-Mills theory in (3+1) dimensions. The\nground state energy and Wilson loops are calculated, and the finite-size\nscaling behaviour is explored. Crude estimates of the string tension are\nderived, which agree with previous results at intermediate couplings; but more\naccurate results for larger loops will be required to establish scaling\nbehaviour at weak coupling.",
        "positive": "A CG Method for Multiple Right Hand Sides and Multiple Shifts in Lattice\n  QCD Calculations: We consider the task of computing solutions of linear systems that only\ndiffer by a shift with the identity matrix as well as linear systems with\nseveral different right hand sides. In the past Krylov subspace methods have\nbeen developed which exploit either the need for solutions to multiple right\nhand sides (e.g. deflation type methods and block methods) or multiple shifts\n(e.g. shifted CG) with some success. In this paper we present a block Krylov\nsubspace method which, based on a block Lanczos process, exploits both features\n- shifts and multiple right hand sides - at once. Such situations arise, for\nexample, in lattice QCD simulations within the Rational Hybrid Monte Carlo\nalgorithm. We give numerical evidence that our method is superior to applying\nother iterative methods to each of the systems individually as well as, in some\ncases, to shifted or block Krylov subspace methods."
    },
    {
        "anchor": "A lattice evaluation of four-quark operators in the nucleon: Nucleon matrix elements of various four-quark operators are evaluated in\nquenched lattice QCD using Wilson fermions. Some of these operators give rise\nto twist-four contributions to nucleon structure functions. Furthermore, they\nbear valuable information about the diquark structure of the nucleon. Mixing\nwith lower-dimensional operators is avoided by considering appropriate\nrepresentations of the flavour group. We find that for a certain flavour\ncombination of baryon structure functions, twist-four contributions are very\nsmall. This suggests that twist-four effects for the nucleon might be much\nsmaller than m_p^2/Q^2.",
        "positive": "Localisation in 2+1 dimensional SU(3) pure gauge theory at finite\n  temperature: I study the localisation properties of low Dirac eigenmodes in 2+1\ndimensional SU(3) pure gauge theory, both in the low-temperature, confined and\nchirally-broken phase and in the high-temperature, deconfined and\nchirally-restored phase, by means of numerical lattice simulations. While these\nmodes are delocalised at low temperature, they become localised at high\ntemperature, up to a critical point in the Dirac spectrum where a BKT-type\nAnderson transition takes place. All results point to localisation appearing at\nthe deconfinement temperature, and support previous expectations about the\nclose relation between deconfinement, chiral symmetry breaking, and\nlocalisation."
    },
    {
        "anchor": "The in-medium heavy quark potential from quenched and dynamical lattice\n  QCD: We present our latest results for the the complex valued static heavy-quark\npotential at finite temperature from lattice QCD. The real and imaginary part\nof the potential are obtained from the position and width of the lowest lying\npeak in the spectral function of the Wilson line correlator in Coulomb gauge.\nSpectral information is extracted from Euclidean time data using a novel\nBayesian approach different from the Maximum Entropy Method. In order to\nextract both the real and imaginary part, we generated anisotropic quenched\nlattices $32^3\\times N_\\tau$ $(\\beta=7.0,\\xi=3.5)$ with $N_\\tau=24,\\ldots,96$,\ncorresponding to $839{\\rm MeV} \\geq T\\geq 210 {\\rm MeV}$. For the case of a\nrealistic QCD medium with light u, d and s quarks we use isotropic\n$48^3\\times12$ ASQTAD lattices with $m_l=m_s/20$ provided by the HotQCD\ncollaboration, which span $286 {\\rm MeV} \\geq T\\geq 148{\\rm MeV}$. We find a\nclean transition from a confining to a Debye screened real part and observe\nthat its values lie close to the color singlet free energies in Coulomb gauge.\nThe imaginary part, estimated on quenched lattices, is found to be of the same\norder of magnitude as in hard-thermal loop (HTL) perturbation theory.",
        "positive": "An alternative to domain wall fermions: We define a sparse hermitian lattice Dirac matrix, $H$, coupling $2n+1$ Dirac\nfermions. When $2n$ fermions are integrated out the induced action for the last\nfermion is a rational approximation to the hermitian overlap Dirac operator. We\nprovide rigorous bounds on the condition number of $H$ and compare them to\nbounds for the higher dimensional Dirac operator of domain wall fermions. Our\nmain conclusion is that overlap fermions should be taken seriously as a\npractical alternative to domain wall fermions in the context of numerical QCD."
    },
    {
        "anchor": "Chiral properties of the fixed point action of the Schwinger model: We study the spectrum properties for a recently constructed fixed point\nlattice Dirac operator. We also consider the problem of the extraction of the\nfermion condensate, both by direct computation, and through the Banks-Casher\nformula by analyzing the density of eigenvalues of a redefined antihermitean\nlattice Dirac operator.",
        "positive": "The generating functional for hadronic weak interactions and its\n  quenched approximation: We derive the generating functional of $|\\Delta S| =1, 2$ hadronic weak\ninteractions at one loop for a generic number of flavours and its counterpart\nin the quenched approximation. A systematic analysis of the ultraviolet\ndivergences in the full theory (with and without a singlet dynamical field) and\nin the quenched case is performed. We show that the quenched chiral logarithms\nin the presence of weak interactions amount to a redefinition of the weak mass\nterm in the $\\Delta S=\\pm 1$ weak effective Lagrangian at leading order.\nFinally, we apply the results to $B_K$ and $K\\to\\pi\\pi$ matrix elements with\n$\\Delta I=1/2,3/2$ to analyze the modifications induced by quenching on the\ncoefficients of chiral logarithms in the one-loop corrections."
    },
    {
        "anchor": "Confining properties of QCD at finite temperature and density: A disorder parameter detecting dual superconductivty of the vacuum is used as\na probe to characterize the confining properties of the phase diagram of two\ncolor QCD at finite temperature and density. We obtain evidence for the\ndisappearing of dual superconductivity (deconfinement) induced by a finite\ndensity of baryonic matter, as well as for a coincidence of this phenomenon\nwith the restoration of chiral symmetry both at zero and finite density. The\nsaturation transition induced by Pauli blocking is studied as well, and a\ngeneral warning is given about the possible effects that this unphysical\ntransition could have on the study of the QCD phase diagram at strong values of\nthe gauge coupling.",
        "positive": "Thermodynamical quantities of lattice full QCD from an efficient method: I extend to QCD an efficient method for lattice gauge theory with dynamical\nfermions. Once the eigenvalues of the Dirac operator and the density of states\nof pure gluonic configurations at a set of plaquette energies (proportional to\nthe gauge action) are computed, thermodynamical quantities deriving from the\npartition function can be obtained for arbitrary flavor number, quark masses\nand wide range of coupling constants, without additional computational cost.\nResults for the chiral condensate and gauge action are presented on the $10^4$\nlattice at flavor number $N_f=0$, 1, 2, 3, 4 and many quark masses and coupling\nconstants. New results in the chiral limit for the gauge action and its\ncorrelation with the chiral condensate, which are useful for analyzing the QCD\nchiral phase structure, are also provided."
    },
    {
        "anchor": "New approach to lattice QCD at finite density; results for the critical\n  end point on coarse lattices: All approaches currently used to study finite baryon density lattice QCD\nsuffer from uncontrolled systematic uncertainties in addition to the well-known\nsign problem. We formulate and test an algorithm, sign reweighting, that works\ndirectly at finite $\\mu = \\mu_B/3$ and is yet free from any such uncontrolled\nsystematics. With this algorithm the {\\em only} problem is the sign problem\nitself. This approach involves the generation of configurations with the\npositive fermionic weight $|{\\rm Re\\; det} D(\\mu)|$ where $D(\\mu)$ is the Dirac\nmatrix and the signs ${\\rm sign} \\; ( {\\rm Re\\; det} D(\\mu) ) = \\pm 1$ are\nhandled by a discrete reweighting. Hence there are only two sectors, $+1$ and\n$-1$ and as long as the average $\\langle\\pm 1\\rangle \\neq 0$ (with respect to\nthe positive weight) this discrete reweighting by the signs carries no overlap\nproblem and the results are reliable. The approach is tested on $N_t = 4$\nlattices with $2+1$ flavors and physical quark masses using the unimproved\nstaggered discretization. By measuring the Fisher (sometimes also called\nLee-Yang) zeros in the bare coupling on spatial lattices $L/a = 8, 10, 12$ we\nconclude that the cross-over present at $\\mu = 0$ becomes stronger at $\\mu > 0$\nand is consistent with a true phase transition at around $\\mu_B/T \\sim 2.4$.",
        "positive": "Anomaly Cancellation Condition in Lattice Gauge Theory: We study the gauge anomaly ${\\cal A}$ defined on a 4-dimensional infinite\nlattice while keeping the lattice spacing finite. We assume that (I) ${\\cal A}$\ndepends smoothly and locally on the gauge potential, (II) ${\\cal A}$ reproduces\nthe gauge anomaly in the continuum theory in the classical continuum limit, and\n(III) U(1) gauge anomalies have a topological property. It is then shown that\nthe gauge anomaly ${\\cal A}$ can always be removed by local counterterms to all\norders in powers of the gauge potential, leaving possible breakings\nproportional to the anomaly in the continuum theory. This follows from an\nanalysis of nontrivial local solutions to the Wess-Zumino consistency condition\nin lattice gauge theory. Our result is applicable to the lattice chiral gauge\ntheory based on the Ginsparg-Wilson Dirac operator, when the gauge field is\nsufficiently weak $\\|U(n,\\mu)-1\\|<\\epsilon'$, where $U(n,\\mu)$ is the link\nvariable and $\\epsilon'$ a certain small positive constant."
    },
    {
        "anchor": "Critical Dynamics of the Hybrid Monte Carlo Algorithm: We investigate the critical dynamics of the Hybrid Monte Carlo algorithm\napproaching the chiral limit of standard Wilson fermions. Our observations are\nbased on time series of lengths O(5000) for a variety of observables. The\nlattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and\nkappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55. We find\nsurprisingly small integrated autocorrelation times for local and extended\nobservables. The dynamical critical exponent $z$ of the exponential\nautocorrelation time is compatible with 2. We estimate the total computational\neffort to scale between V^2 and V^2.25 towards the chiral limit.",
        "positive": "Dynamical Wilson fermions and the problem of the chiral limit in compact\n  lattice QED: We compare the approach to the chiral transition line $~\\kappa_c(\\bt)~$ in\nquenched and full compact lattice QED with Wilson fermions within the\nconfinement phase, especially in the pseudoscalar sector of the theory. We show\nthat in the strong coupling limit ($\\beta =0$) the quenched theory is a good\napproximation to the full one, in contrast to the case of $\\beta =0.8$. At the\nlarger $\\beta$-value the transition in the full theory is inconsistent with the\nzero--mass limit of the pseudoscalar particle, thus prohibiting the definition\nof a chiral limit."
    },
    {
        "anchor": "New developments in lattice QCD on equilibrium physics and phase diagram: I review recent new lattice QCD results on a few selected topics which are\nrelevant to the heavy ion physics community. Special emphasis is put on the QCD\nphase diagram towards the chiral limit and at nonzero baryon density as well as\nthe fate of quarkonia and heavy quark drag coefficients.",
        "positive": "Evidence for charm-bottom tetraquarks and the mass dependence of\n  heavy-light tetraquark states from lattice QCD: We continue our study of heavy-light four-quark states and find evidence from\nlattice QCD for the existence of a strong-interaction-stable $I(J^P)=0(1^+)$\n$ud\\bar{c}\\bar{b}$ tetraquark with mass in the range of 15 to 61 MeV below\n$\\bar{D}B^*$ threshold. Since this range includes the electromagnetic\n$\\bar{D}B\\gamma$ decay threshold, current uncertainties do not allow us to\ndetermine whether such a state would decay electromagnetically, or only weakly.\nWe also perform a study at fixed pion mass, with NRQCD for the heavy quarks,\nsimulating $qq^\\prime \\bar{b}^\\prime \\bar{b}$ and $q q^\\prime\n\\bar{b}^\\prime\\bar{b}^\\prime$ tetraquarks with $q,\\, q^\\prime =ud$ or $\\ell s$\nand variable, unphysical $m_{b^\\prime}$ in order to investigate the heavy\nmass-dependence of such tetraquark states. We find that the dependence of the\nbinding energy follows a phenomenologically-expected form and that, though\nNRQCD breaks down before $m_{b^\\prime}=m_c$ is reached, the results at higher\n$m_{b^\\prime}$ clearly identify the $ud\\bar{b}^\\prime \\bar{b}$ channel as the\nmost likely to support a strong-interaction-stable tetraquark state at\n$m_{b^\\prime}=m_c$. This observation serves to motivate the direct\n$ud\\bar{c}\\bar{b}$ simulation. Throughout we use dynamical $n_f=2+1$ ensembles\nwith pion masses $m_\\pi=$415, 299, and 164 MeV reaching down almost to the\nphysical point, a relativistic heavy quark prescription for the charm quark,\nand NRQCD for the bottom quark(s)."
    },
    {
        "anchor": "Lattice Gauge Theories at the Energy Frontier: This White Paper has been prepared as a planning document for the Division of\nHigh Energy Physics of the U. S. Department of Energy. Recent progress in\nlattice-based studies of physics beyond the standard model is summarized, and\nmajor current goals of USQCD research in this area are presented. Challenges\nand opportunities associated with the recently discovered 126 GeV Higgs-like\nparticle are highlighted. Computational resources needed for reaching important\ngoals are described. The document was finalized on February 11, 2013 with\nreferences that are not aimed to be complete, or account for an accurate\nhistorical record of the field.",
        "positive": "Quark propagator in a covariant gauge: Using mean--field improved gauge field configurations, we compare the results\nobtained for the quark propagator from Wilson fermions and Overlap fermions on\na $\\3$ lattice at a spacing of $a=0.125(2)$ fm."
    },
    {
        "anchor": "B-physics from non-perturbatively renormalized HQET in two-flavour\n  lattice QCD: We report on the ALPHA Collaboration's lattice B-physics programme based on\nN_f=2 O(a) improved Wilson fermions and HQET, including all NLO effects in the\ninverse heavy quark mass, as well as non-perturbative renormalization and\nmatching, to fix the parameters of the effective theory. Our simulations in\nlarge physical volume cover 3 lattice spacings a ~ (0.08-0.05) fm and pion\nmasses down to 190 MeV to control continuum and chiral extrapolations. We\npresent the status of results for the b-quark mass and the B_(s)-meson decay\nconstants, f_B and f_{B_s}.",
        "positive": "Towards the computation of inclusive decay rates using lattice QCD: We present a non-perturbative computation of inclusive rates of semileptonic\ndecays of heavy mesons from lattice QCD simulations. The calculation is based\non the extraction of smeared spectral functions obtained from four-point\nEuclidean correlation functions computed on configuration ensembles of the\nJLQCD and ETM collaborations. We compare our results for the inclusive decay\nrates with analytical predictions from the operator-product expansion, finding\na good agreement for the calculation of the inclusive decay rate. This opens\nthe path to the theoretical determination of the magnitude of the\nCabibbo-Kobayashi-Maskawa matrix element $V_{cb}$ to a level of precision\ncompetitive with the present experimental uncertainty."
    },
    {
        "anchor": "A construction of the Schr\u00f6dinger Functional for M\u00f6bius Domain Wall\n  Fermions: We construct the Schr\\\"odinger Functional (SF) setup for the M\\\"obius domain\nwall fermions (MDWF). The method is an extension of the method proposed by\nTakeda for the standard domain wall fermion. In order to fulfill the\nrequirement that the lattice Dirac operator with the SF boundary obeys the\nL\\\"uscher's universality argument: the lattice chiral fermion with the SF\nboundary condition breaks the chiral symmetry at the temporal boundary, we\nimpose the parity symmetry with respect to the fifth-direction on the MDWF\noperator. This additional symmetry restricts the choice of the parameter of the\nMDWF so that the optimal parameter from the Zolotarev optimal approximation\ncannot be applied. We introduce a modified parameter set having the\nfifth-dimensional parity symmetry. We investigate the MDWF with the SF boundary\nby observing eigenvalues of the Hermitian operator and the Ginsparg-Wilson\nrelation violation at the tree-level. We compare the computational cost with\nthat of the standard DWF with the SF scheme.",
        "positive": "Heavy Quark Physics in Nf=2 QCD: We present a preliminary analysis of the heavy-heavy spectrum and heavy-light\ndecay constants in full QCD, using a tadpole-improved SW quark action and an\nRG-improved gauge action on a 16^3 x 32 lattice with four sea quark masses\ncorresponding to m_pi/m_rho = 0.8, 0.75, 0.7, 0.6 and a^-1 = 1.3 GeV. We focus\nparticularly on the effect of sea quarks on these observables."
    },
    {
        "anchor": "Simulating non-commutative field theory: Non-commutative (NC) field theories can be mapped onto twisted matrix models.\nThis mapping enables their Monte Carlo simulation, where the large N limit of\nthe matrix models describes the continuum limit of NC field theory. First we\npresent numeric results for 2d NC gauge theory of rank 1, which turns out to be\nrenormalizable. The area law for the Wilson loop holds at small area, but at\nlarge area we observe a rotating phase, which corresponds to an Aharonov-Bohm\neffect. Next we investigate the NC phi^4 model in d=3 and explore its phase\ndiagram. Our results agree with a conjecture by Gubser and Sondhi in d=4, who\npredicted that the ordered regime splits into a uniform phase and a phase\ndominated by stripe patterns.",
        "positive": "Taylor- and fugacity expansion for the effective Z(3) spin model of QCD\n  at finite density: Series expansions in the chemical potential mu are studied for an effective\ntheory of QCD which has a flux representation where the complex action is\novercome. In particular we consider fugacity series, Taylor expansion and a\nmodified Taylor expansion and compare the outcome of these series to the\nreference results from a Monte Carlo simulation in the flux representation\nwhere arbitrary mu is accessible. It is shown that for most parameter values\nthe fugacity expansion gives the best approximation to the data from the flux\nsimulation, followed by our newly proposed modified Taylor expansion. For the\nconventional Taylor expansion we find that the results coincide with the flux\ndata only for very small mu."
    },
    {
        "anchor": "Precision calculation of the electromagnetic radii of the proton and\n  neutron from lattice QCD: We present lattice-QCD results for the electromagnetic form factors of the\nproton and neutron including both quark-connected and -disconnected\ncontributions. The parametrization of the $Q^2$-dependence of the form factors\nis combined with the extrapolation to the physical point. In this way, we\ndetermine the electric and magnetic radii and the magnetic moments of the\nproton and neutron. For the proton, we obtain at the physical pion mass and in\nthe continuum and infinite-volume limit $\\sqrt{\\langle r_E^2 \\rangle^p} =\n0.820(14)$ fm, $\\sqrt{\\langle r_M^2 \\rangle^p} = 0.8111(89)$ fm, and $\\mu_M^p =\n2.739(66)$, where the errors include all systematics.",
        "positive": "Non-perturbatively Improved Heavy-Light Mesons: Masses and Decay\n  Constants: We present a study of the heavy-light spectrum and of the D- and B-meson\ndecay constants. The results wer e obtained in the quenched approximation, by\nusing the non-perturbatively improved Clover lattice action at beta=6.2, with a\nsample of 100 configurations, on a 24^3 x 64 lattice. After a careful analysis\nof th e systematic errors present in the extraction of the physical results, by\nassuming quite conservative discretization errors, we find f_Ds=231 +/-\n12^{+6}_{-1} MeV, f_D = 211 +/- 14^{+0}_{-12} MeV, f_Ds/f_D=1.10(2), f_Bs = 204\n+/- 16^{+28}_{-0} MeV, f_B = 179 +/- 18^{+26}_{-9} MeV,\nf_Bs/f_B=1.14(3)^{+0}_{-1}. Our results, which have smaller discretization\nerrors than many previous estimates at fixed value of the lattice spacing $a$,\nsupport a large value of f_B in the quenched approximation."
    },
    {
        "anchor": "2+1 flavor fine lattice simulation at finite temperature with\n  domain-wall fermions: Simulations for the thermodynamics of the 2+1 flavor QCD are performed\nemploying chiral fermions. The use of M\\\"obius domain-wall fermions with\nstout-link smearing is more effective on the finer lattices where all the\nrelevant chiral symmetries are realized more accurately. We report on the\ninitial simulations near the (pseudo) critical point using the line of constant\nphysics with an average $ud$ quark mass slightly heavier than physical at\n$a\\lesssim 0.1$ fm.",
        "positive": "Chiral Symmetry Breaking in Abelian-Projected SU(2) Lattice Gauge Theory: Chiral symmetry breaking parameters are calculated in quenched SU(2) gauge\ntheory and with Abelian gauge fields projected in maximal Abelian gauge and in\nfield strength gauge. Maximal Abelian gauge projected fields lead to chiral\ncondensate values which are quite similar to those of the full nonabelian\ntheory. Pseudoscalar and vector meson correlators are calculated and found to\nbe reproduced by the use of maximal Abelian gauge fields for small quark\nmasses. In field-strength gauge, Abelian-projected fields give a chiral\ncondensate which closely resembles the results of strongly coupled ($\\beta<1$)\ngauge theory: the chiral condensate is insensitive to $\\beta$ and quark mass\nand hence violates scaling badly."
    },
    {
        "anchor": "Exotics: We review lattice QCD results for glueballs (including a discussion of mixing\nwith scalar mesons), hybrid mesons and other exotic states (such as $B_s B_s$\nmolecules).",
        "positive": "Lattice QCD study of $B_s\\to D_s \\ell \\bar\u03bd_\\ell$ decay near zero\n  recoil: We study the hadronic matrix elements describing the $B_s \\to D_s\\ell\n\\bar\\nu_\\ell$ decay in and beyond the Standard Model. By using the twisted mass\nQCD on the lattice with $N_f=2$ dynamical flavors we compute the normalization\n$\\mathscr G_s(1)$ of the form factor dominating $B_s\\to D_s \\ell \\bar\\nu_\\ell$\nin the SM. We also make the first lattice determination of $F_0(q^2)/F_+(q^2)$\nand $F_T(q^2)/F_+(q^2)$ near zero recoil (near $q^2_{\\rm max}$). We briefly\ndiscuss the non-strange case $B \\to D\\ell \\bar\\nu_\\ell$ as well."
    },
    {
        "anchor": "Self-mitigating Trotter circuits for SU(2) lattice gauge theory on a\n  quantum computer: Quantum computers offer the possibility to implement lattice gauge theory in\nMinkowski rather than Euclidean spacetime, thus allowing calculations of\nprocesses that evolve in real time. In this work, calculations within SU(2)\npure gauge theory are able to show the motion of an excitation traveling across\na spatial lattice in real time. This is accomplished by using a simple yet\npowerful method for error mitigation, where the original circuit is used both\nforward and backward in time. For a two-plaquette lattice, meaningful results\nare obtained from a circuit containing hundreds of CNOT gates. The same method\nis used for a five-plaquette lattice, where calculations show that residual\nsystematic effects can be reduced through follow-up mitigation.",
        "positive": "A derivation of Regge trajectories in large-N transverse lattice QCD: Large-N QCD is analysed in light-front coordinates with a transverse lattice\nat strong coupling. The general formalism can be looked up on as a d+n\nexpansion with a stack of d-dimensional hyperplanes uniformly spaced in n\ntransverse dimensions. It can arise by application of the renormalisation group\ntransformations only in the transverse directions. At leading order in strong\ncoupling, the gauge field dynamics reduces to the constraint that only colour\nsinglet states can jump between the hyperplanes. With d=2, n=2 and large-N, the\nleading order strong coupling results are simple renormalisations of those for\nthe 't Hooft model. The meson spectrum lies on a set of parallel trajectories\nlabeled by spin. This is the first derivation of the widely anticipated Regge\ntrajectories in a regulated systematic expansion in QCD."
    },
    {
        "anchor": "(Approximate) Low-Mode Averaging with a new Multigrid Eigensolver: We present a multigrid based eigensolver for computing low-modes of the\nHermitian Wilson Dirac operator. For the non-Hermitian case multigrid methods\nhave already replaced conventional Krylov subspace solvers in many lattice QCD\ncomputations. Since the $\\gamma_5$-preserving aggregation based interpolation\nused in our multigrid method is valid for both, the Hermitian and the\nnon-Hermitian case, inversions of very ill-conditioned shifted systems with the\nHermitian operator become feasible. This enables the use of multigrid within\nshift-and-invert type eigensolvers. We show numerical results from our MPI-C\nimplementation of a Rayleigh quotient iteration with multigrid. For\nstate-of-the-art lattice sizes and moderate numbers of desired low-modes we\nachieve speed-ups of an order of magnitude and more over PARPACK. We show\nresults and develop strategies how to make use of our eigensolver for\ncalculating disconnected contributions to hadronic quantities that are noisy\nand still computationally challenging. Here, we explore the possible benefits,\nusing our eigensolver for low-mode averaging and related methods with high and\nlow accuracy eigenvectors. We develop a low-mode averaging type method using\nonly a few of the smallest eigenvectors with low accuracy. This allows us to\navoid expensive exact eigensolves, still benefitting from reduced statistical\nerrors.",
        "positive": "Gluonic observables and the scalar spectrum of twelve-flavour QCD: We measure glueball masses and the string tension in twelve-flavour QCD,\naiming at comparing the emerging gluonic spectrum to the mesonic one. When\napproaching the critical surface at zero quark mass, the hierarchy of masses in\nthe different sectors of the spectrum gives a new handle to determine the\nexistence of an infrared fixed point. We describe the details of our gluonic\nmeasurements and the results obtained on a large number of gauge configurations\ngenerated with the HISQ action. In particular, we focus on the scalar glueball\nand its mixing with a flavour-singlet fermionic state, which is lighter than\nthe pseudoscalar (would-be pion) state. The results are interesting in view of\na light composite Higgs boson in walking technicolor theories."
    },
    {
        "anchor": "Chiral crystals in strong-coupling lattice QCD at nonzero chemical\n  potential: We study the effective action for strong-coupling lattice QCD with\none-component staggered fermions in the case of nonzero chemical potential and\nzero temperature. The structure of this action suggests that at large chemical\npotentials its ground state is a crystalline `chiral density wave' that\nspontaneously breaks chiral symmetry and translation invariance. In mean-field\ntheory, on the other hand, we find that this state is unstable. We show that\nlattice artifacts are partly responsible for this, and suggest that if this\nphase exists in QCD, then finding it in Monte-Carlo simulations would require\nsimulating on relatively fine lattices. In particular, the baryon mass in\nlattice units, m_B, should be considerably smaller than its strong-coupling\nlimit of m_B~3.",
        "positive": "Lattice QCD calculation of the proton decay matrix element in the\n  continuum limit: We present a quenched lattice QCD calculation of the \\alpha and \\beta\nparameters of the proton decay matrix element. The simulation is carried out\nusing the Wilson quark action at three values of the lattice spacing in the\nrange a\\approx 0.1-0.064 fm to study the scaling violation effect. We find only\nmild scaling violation when the lattice scale is determined by the nucleon\nmass. We obtain in the continuum limit,\n|\\alpha(NDR,2GeV)|=0.0090(09)(^{+5}_{-19})GeV^3 and\n|\\beta(NDR,2GeV)|=0.0096(09)(^{+6}_{-20})GeV^3 with \\alpha and \\beta in a\nrelatively opposite sign, where the first error is statistical and the second\nis due to the uncertainty in the determination of the physical scale."
    },
    {
        "anchor": "Glueball Spins in $ D=3$ Yang-Mills: We determine spins of more than 100 low lying glueball states in $D=2+1$\ndimensional $SU(4)$ gluodynamics by a lattice calculation. We go up to $J=8$ in\nthe spin value. We compare the resulting spectrum with predictions of the\nAxionic String Ansatz (ASA). We find a perfect match for 39 lightest states,\ncorresponding to the first four string levels. In particular, this resolves\ntensions between the ASA predictions and earlier spin determinations. The\nobserved spins of heavier glueballs are also in a good agreement with the ASA.\nWe did not identify any sharp tension between lattice data and the ASA, but\nmore work is needed to fully test the ASA predictions for the spins of 64\nstates at the fifth string level.",
        "positive": "Kaon semileptonic vector form factor and determination of |V_{us}| using\n  staggered fermions: Using staggered fermions and twisted boundary conditions, we calculate the K\nmeson semileptonic decay vector form factor at zero momentum transfer. The HISQ\nformulation is used for the valence quarks, while the sea quarks are simulated\nwith the asqtad action (MILC N_f=2+1 configurations). For the chiral and\ncontinuum extrapolation we use two-loop continuum CHPT, supplemented by\npartially quenched staggered CHPT at one loop. Our result is f_+^{K\\pi}(0) =\n0.9667+-0.0023+-0.0033, where the first error is statistical and the second is\nthe sum in quadrature of the systematic uncertainties. This result is the first\nN_f=2+1 calculation with two lattice spacings and a controlled continuum\nextrapolation. It is also the most precise result to date for the vector form\nfactor and, although the central value is larger than previous unquenched\nlattice calculations, it is compatible with them within errors. Combining our\nvalue for f_+^{K\\pi}(0) with the latest experimental measurements of K\nsemileptonic decays, we obtain |V_{us}| = 0.2238+-0.0009+-0.0005, where the\nfirst error is from f_+^{K\\pi}(0) and the second one is experimental. As a\nbyproduct of our calculation, we obtain the combination of low-energy constants\n[C_{12}^r+C_{34}^r-(L_5^r)^2](M_\\rho) = (3.62+-1.00)x10^{-6}."
    },
    {
        "anchor": "Competing order in the fermionic Hubbard model on the hexagonal graphene\n  lattice: We study the phase diagram of the fermionic Hubbard model on the hexagonal\nlattice in the space of on-site and nearest neighbor couplings with\nHybrid-Monte-Carlo simulations. With pure on-site repulsion this allows to\ndetermine the critical coupling strength for spin-density wave formation with\nthe standard approach of introducing a small mass term, explicitly breaking the\nsublattice symmetry. The analogous mass term for charge-density wave formation\nabove a critical nearest-neighbor repulsion, on the other hand, would introduce\na fermion sign problem. The competition between the two and the phase diagram\nin the space of the two coouplings can however be studied in simulations\nwithout explicit sublattice symmetry breaking. Our results compare\nqualitatively well with the Hartree-Fock phase diagram. We furthermore\ndemonstrate how spin-symmetry breaking by the Euclidean time discretization can\nbe avoided also, when using an improved fermion action based on an exponetial\ntransfer matrix with exact sublattice symmetry.",
        "positive": "Thermal Broadening of Bottomonia: Lattice Non-Relativistic QCD with\n  Extended Operators: We present lattice non-relativistic QCD calculations of bottomonium\ncorrelation functions at temperatures $T \\simeq 150-350$ MeV. The correlation\nfunctions were computed using extended bottomonium operators, and on background\ngauge-field configurations for 2+1-flavor QCD having physical kaon and\nnearly-physical pion masses. We analyzed these correlation functions based on\nsimple theoretically-motivated parameterizations of the corresponding spectral\nfunctions. The results of our analyses are compatible with significant\nin-medium thermal broadening of the ground state S- and P-wave bottomonia."
    },
    {
        "anchor": "On Equation of State at physical quark masses: QCD equation of state is calculated in (2+1) flavor QCD at temperatures\ncorresponding fermion action on lattices with temporal extent $N_{\\tau}=8$. The\nresults are compared with previous calculations performed at twice larger\nvalues of the light quark masses as well as with results obtained from the\nresonance gas model calculation. The deconfining and chiral aspects of the QCD\ntransition are also discussed",
        "positive": "Charmed meson decay constants in three-flavor lattice QCD: We present the first lattice QCD calculation with realistic sea quark content\nof the D^+ meson decay constant f_{D^+}. We use the MILC Collaboration's\npublicly available ensembles of lattice gauge fields, which have a quark sea\nwith two flavors (up and down) much lighter than a third (strange). We obtain\nf_{D^+} = 201 +/- 3 +/- 17 MeV, where the errors are statistical and a\ncombination of systematic errors. We also obtain f_{D_s} = 249 +/- 3 +/- 16 MeV\nfor the D_s meson."
    },
    {
        "anchor": "Polyakov loop analysis with Dirac-mode expansion: In order to investigate the direct relation between confinement and chiral\nsymmetry breaking in QCD, we investigate the Polyakov loop in terms of the\nDirac eigenmodes in both confined and deconfined phases. Using the Dirac-mode\nexpansion method in SU(3) lattice QCD, we analyze the contribution of low-lying\nand higher Dirac-modes to the Polyakov loop, respectively.In the confined phase\nbelow T_c, after removing low-lying Dirac-modes, the chiral condensate $<\n\\bar{q} q>$ is largely reduced, however, the Polyakov loop remains almost zero\nand Z_3-center symmetry is unbroken. These results indicate that the system is\nstill in the confined phase without low-lying Dirac-modes. By higher\nDirac-modes cut, the Polyakov loop also remains almost zero below T_c. We also\nanalyze the Polyakov loop in the deconfined phase above T_c. We find that the\nPolyakov loop and Z_3-symmetry behavior are insensitive to low-lying and higher\nDirac-modes in both confined and deconfined phases.",
        "positive": "Determining the scale in Lattice QCD: We discuss scale setting in the context of 2+1 dynamical fermion simulations\nwhere we approach the physical point in the quark mass plane keeping the\naverage quark mass constant. We have simulations at four beta values, and after\ndetermining the paths and lattice spacings, we give an estimation of the\nphenomenological values of various Wilson flow scales."
    },
    {
        "anchor": "Gradient flow representation of the four-dimensional $\\mathcal{N}=2$\n  super Yang--Mills supercurrent: In K.~Hieda, A.~Kasai, H.~Makino, and H.~Suzuki, Prog.\\ Theor.\\ Exp.\\ Phys.\\\n\\textbf{2017}, 063B03 (2017), a properly normalized supercurrent in the\nfour-dimensional (4D) $\\mathcal{N}=1$ super Yang--Mills theory (SYM) that works\nwithin on-mass-shell correlation functions of gauge-invariant operators is\nexpressed in a regularization-independent manner by employing the gradient\nflow. In the present paper, this construction is extended to the supercurrent\nin the 4D $\\mathcal{N}=2$ SYM. The so-constructed supercurrent will be useful,\nfor instance, for fine tuning of lattice parameters toward the supersymmetric\ncontinuum limit in future lattice simulations of the 4D $\\mathcal{N}=2$ SYM.",
        "positive": "Scaling properties of multiscale equilibration: We investigate the lattice spacing dependence of the equilibration time for a\nrecently proposed multiscale thermalization algorithm for Markov chain Monte\nCarlo simulations. The algorithm uses a renormalization-group matched coarse\nlattice action and prolongation operation to rapidly thermalize decorrelated\ninitial configurations for evolution using a corresponding target lattice\naction defined at a finer scale. Focusing on non-topological long-distance\nobservables in pure SU(3) gauge theory, we provide quantitative evidence that\nthe slow modes of the Markov process, which provide the dominant contribution\nto the rethermalization time, have a suppressed contribution toward the\ncontinuum limit, despite their associated timescales increasing. Based on these\nnumerical investigations, we conjecture that the prolongation operation used\nherein will produce ensembles that are indistinguishable from the target\nfine-action distribution for a sufficiently fine coupling at a given level of\nstatistical precision, thereby eliminating the cost of rethermalization."
    },
    {
        "anchor": "Nucleon mass and strange content from (2+1)-flavor Domain Wall Fermion: We report on our ongoing study of nucleon properties, the nucleon mass and\nthe strange quark content (<N|ss|N>) in particular. These calculations are done\non (2+1)-flavor Domain Wall Fermion (DWF) ensembles with Iwasaki gauge action\nwith 2 different lattice spacings (a ~ 0.08, 0.11fm) and DWF with Dislocation\nSuppressing Determinant Ratio(DSDR) (a ~ 0.14fm), generated by RBC/UKQCD\ncollaborations.",
        "positive": "Real Time Simulations in Lattice Gauge Theory: I review the study of real (Minkowski) time correlators in hot, weakly\ncoupled Yang-Mills theory via lattice methods. I concentrate on the Minkowski\ntime topological susceptibility, which is related to the efficiency of baryon\nnumber violation at high temperature. It can be computed by approximating the\nIR fields as classical and solving their dynamics nonperturbatively on the\nlattice. However it is essential to include the UV degrees of freedom. Their\ninfluence can be computed perturbatively and included in the lattice model by\nthe addition of auxiliary fields."
    },
    {
        "anchor": "Strange Nuclear Physics from QCD on Lattice: We study single-particle potential of Lambda, Sigma, and Xi hyperons in\nnucleonic matter starting from the fundamental theory of the strong\ninteraction, QCD. First we carry out a lattice QCD numerical simulation, and\nextract baryon-baryon interactions from QCD by means of the HAL QCD method. We\nemploy a full QCD gauge configuration ensemble at almost physical point so that\nwe can study the physical world, hence mass of hadrons are nearly physical, for\nexample, pion mass is 146 MeV, kaon mass is 525 MeV, and nucleon mass is 958\nMeV. Then, we apply the obtained hyperon interactions to the\nBrueckner-Hartree-Fock many-nucleon theory, and calculate single-particle\npotential of hyperons in nucleonic matter U_{Y}(k). We obtain for hyperons\nstopping in the symmetric nuclear matter at the normal nuclear matter density,\nU_{Lambda}(0)=-28 MeV, U_{Sigma}(0)=+15 MeV, and U_{Xi}(0)=-4 MeV with a\nstatistical error about +/- 2 MeV associated with our Monte Carlo simulation.\nThese results are qualitatively compatible with values suggested from\nhypernuclear experiments. This success is remarkable and very encouraging since\nthis proves that our approach to strange nuclear physics starting from QCD is\nessentially correct.",
        "positive": "QCD Phase Diagram with 2-flavor Lattice Fermion Formulations: We propose a new framework for investigating two-flavor lattice QCD with\nfinite temperature and density by applying the Karsten-Wilczek lattice fermion,\nin which a species-dependent imaginary chemical potential can reduce the number\nof species to two without losing chiral symmetry. This lattice discretization\nis useful for study on finite-(T,\\mu) QCD since its discrete symmetries are\nappropriate for the case. To show its applicability, we study strong-coupling\nlattice QCD with temperature and chemical potential. We derive the effective\npotential of the scalar meson field and obtain a critical line of the chiral\nphase transition, which is qualitatively consistent with the phenomenologically\nexpected phase diagram."
    },
    {
        "anchor": "Search for Effective Lattice Action of Pure QCD: We study a coupling flow of pure QCD gauge system by using the Monte Carlo\nRenormalization Group method. A rough location of the renormalized trajectory\nin two coupling space is obtained. Also we compare 4 different actions;\n(a)standard Wilson, (b)Symanzik's, (c)Iwasaki's and (d)QCDTARO's. The\nrotational symmetry is restored better as an action gets close to the\nrenormalized trajectory.",
        "positive": "Lattice determination of the pion mass difference $M_{\u03c0^{+}} -\n  M_{\u03c0^{0}}$ at order $\\mathcal{O}(\u03b1_{em})$ and $\\mathcal{O}(\n  (m_{d}-m_{u})^{2})$ including disconnected diagrams: We present our preliminary results concerning the charged/neutral pion mass\ndifference $M_{\\pi^{+}} - M_{\\pi^{0}}$ at order $\\mathcal{O}(\\alpha_{em})$ in\nthe QED interactions, and for $M_{\\pi^{+}} - M_{\\pi^{0}}$ at order\n$\\mathcal{O}\\left( (m_{d}-m_{u})^{2}\\right)$ in the strong isospin-breaking\nterm. The latter contribution provides a determination of the $\\rm{SU}(2)$\nchiral perturbation theory low-energy constant $\\ell_{7}$, whose present\nestimate is affected by a rather large uncertainty. The disconnected\ncontributions appearing in the diagrammatic expansion of $M_{\\pi^{+}} -\nM_{\\pi^{0}}$, being very noisy, are notoriously difficult to evaluate and have\nbeen neglected in our previous calculations. By making use of twisted mass\nLattice QCD simulations and adopting the RM123 method, we will show that taking\nprofit from our recently proposed rotated twisted-mass (RTM) scheme, tailored\nto improve the signal on these kinds of observables, it is possible to evaluate\nthe disconnected diagrams with good precision. For the QED induced pion mass\ndifference, we obtain, after performing the extrapolation towards the continuum\nand thermodynamic limit and at the physical point, the preliminary value\n$M_{\\pi^{+}}-M_{\\pi^{0}} = 4.622~(95)~{\\rm MeV}$, that is in good agreement\nwith the experimental result. For the determination of the low-energy constant\n$\\ell_{7}$, our result $\\ell_{7} = 2.5~(1.4)\\times 10^{-3}$, which is limited\nso far to a single lattice spacing, is in agreement and improves\nphenomenological estimates."
    },
    {
        "anchor": "Static-light meson masses from twisted mass lattice QCD: We compute the static-light meson spectrum using two-flavor Wilson twisted\nmass lattice QCD. We have considered five different values for the light quark\nmass corresponding to 300 MeV < m_PS < 600 MeV. We have extrapolated our\nresults, to make predictions regarding the spectrum of B and B_s mesons.",
        "positive": "$K \u03c0$ scattering at physical pion mass using distillation: Scattering at physical pion mass is still an exploratory field in lattice\nQCD. This generally involves the extraction of excited states through\nmulti-particle correlators on systems with resonances. In that context,\ndistillation has been demonstrated to be effective both as a smearing kernel\nand a computational tool. Motivated by the study of the smearing profile of the\ndistillation operator, we compare stochastic and exact distillation cases for\ndifferent numbers of Laplacian eigenvectors using an RBC-UKQCD $N_f=2+1$\ndomain-wall fermion lattice with a physical pion mass."
    },
    {
        "anchor": "The Strongly Coupled 't Hooft Model on the Lattice: We study the strong coupling limit of the one-flavor and two-flavor massless\n't Hooft models, $large-{\\cal N}_c$-color $QCD_2$, on a lattice. We use\nstaggered fermions and the Hamiltonian approach to lattice gauge theories. We\nshow that the one-flavor model is effectively described by the\nantiferromagnetic Ising model, whose ground state is the vacuum of the gauge\nmodel in the infinite coupling limit; expanding around this ground state we\nderive a strong coupling expansion and compute the lowest lying hadron masses\nas well as the chiral condensate of the gauge theory. Our lattice computation\nwell reproduces the results of the continuum theory. Baryons are massless in\nthe infinite coupling limit; they acquire a mass already at the second order in\nthe strong coupling expansion in agreement with the Witten argument that\nbaryons are the $QCD$ solitons.\n  The spectrum and chiral condensate of the two-flavor model are effectively\ndescribed in terms of observables of the quantum antiferromagnetic Heisenberg\nmodel. We explicitly write the lowest lying hadron masses and chiral condensate\nin terms of spin-spin correlators on the ground state of the spin model. We\nshow that the planar limit (${\\cal N}_c\\longrightarrow \\infty$) of the gauge\nmodel corresponds to the large spin limit ($S\\longrightarrow \\infty$) of the\nantiferromagnet and compute the hadron mass spectrum in this limit finding\nthat, also in this model, the pattern of chiral symmetry breaking of the\ncontinuum theory is well reproduced on the lattice.",
        "positive": "Scaling, topological tunneling and actions for weak coupling DWF\n  calculations: We present results from a 2+1 flavor DWF calculation at 1/a = 3 GeV and\ndiscuss strategies for similar calculations at finer lattice spacings which\nwill target charm physics. At weak coupling the autocorrelation time of the\nglobal topological charge becomes very long because the HMC algorithm has\ntrouble moving between topological sectors. We report the results of\nsimulations that test two ideas for reducing the autocorrelation time of\ntopological charge. In weak coupling quenched simulations we find that the open\nboundary conditions suggested by L\\\"uscher and Schaefer do not prevent the\nappearance of extremely long autocorrelation times for topological observables.\nWe discuss the idea of a \"dislocation-enhancing determinant\" and show that it\ncan produce an increase in topological tunneling."
    },
    {
        "anchor": "Asymptotic low-temperature critical behavior of two-dimensional\n  multiflavor lattice SO(Nc) gauge theories: We address the interplay between global and local gauge nonabelian symmetries\nin lattice gauge theories with multicomponent scalar fields. We consider\ntwo-dimensional lattice scalar nonabelian gauge theories with a local SO(Nc)\n(Nc >= 3) and a global O(Nf) invariance, obtained by partially gauging a\nmaximally O(Nf x Nc)-symmetric multicomponent scalar model. Correspondingly,\nthe scalar fields belong to the coset S(Nf Nc-1)/SO(Nc), where S(N) is the\nN-dimensional sphere. In agreement with the Mermin-Wagner theorem, these\nlattice SO(Nc) gauge models with Nf >= 3 do not have finite-temperature\ntransitions related to the breaking of the global nonabelian O(Nf) symmetry.\nHowever, in the zero-temperature limit they show a critical behavior\ncharacterized by a correlation length that increases exponentially with the\ninverse temperature, similarly to nonlinear O(N) sigma models. Their universal\nfeatures are investigated by numerical finite-size scaling methods. The results\nshow that the asymptotic low-temperature behavior belongs to the universality\nclass of the two-dimensional RP(Nf-1) model.",
        "positive": "Pion physics in two flavor strong coupling lattice QED: We consider the lattice field theory involving two flavors of staggered\nquarks which interact with $U_A(1)$ gauge fields in the strong coupling limit.\nFor massless quarks, this theory has an $SU_L(2)\\times SU_R(2) \\times U_A(1)$\nsymmetry. We show explicitly how pions emerge through the phenomena of\nconfinement in this theory. We also show how one can incorporate the physics of\nthe anomaly in this theory. Thus, our approach is a good pedagogical tool to\nexplain how pions arise in real QCD. Another advantage of our approach is that\nwe can easily design efficient cluster algorithms to compute a variety of\nquantities close to the chiral limit, thus allowing us to understand the low\nenergy physics in a QCD-like setting from first principles."
    },
    {
        "anchor": "Phase Structure of Lattice QCD at Finite Density with Dynamical Fermions: We compare the chemical potential associated with the onset of non-zero\nbaryon number density on $6^4$ and $8^4$ lattices at $\\beta=5.1$ and ma=0.01.\nWe provide evidence for $Z(3)$ tunnelling. We determine a critical chemical\npotential of $\\mu a \\simeq 0.1$ which is unexpectedly low. We also determine\nthe dependence of the onset of the observed phase transition on the quark mass.\nThe physically misleading result of the quenched theory is shown to persist\ndespite the inclusion of the complex fermion determinant.",
        "positive": "The basis of the physical Hilbert space of lattice gauge theories: Non-linear Fourier analysis on compact groups is used to construct an\northonormal basis of the physical (gauge invariant) Hilbert space of\nHamiltonian lattice gauge theories. In particular, the matrix elements of the\nHamiltonian operator involved are explicitly computed. Finally, some\napplications and possible developments of the formalism are discussed."
    },
    {
        "anchor": "Pion form factor from all-to-all propagators of overlap quarks: We report on our calculation of the pion electromagnetic form factor with\ntwo-flavors of dynamical overlap quarks. Gauge configurations are generated\nusing the Iwasaki gauge action on a 16^3 \\times 32 lattice at the lattice\nspacing of 0.12fm with sea quark masses down to m_s/6, where m_s is the\nphysical strange quark mass. We describe our setup to measure the form factor\nthrough all-to-all quark propagators and present preliminary results.",
        "positive": "Gauge Invariance and Confinement in Noncompact Simulations of SU(2): Wilson loops have been measured at strong coupling, $\\beta=0.5$, on a $12^4$\nlattice in a noncompact simulation of pure SU(2) in which random compact gauge\ntransformations impose a kind of lattice gauge invariance. The Wilson loops\nsuggest a confining potential."
    },
    {
        "anchor": "Non-equilibrium dynamics of topological defects in the 3d O(2) model: We present a study of the 3d O(2) non-linear $\\sigma$-model on the lattice,\nwhich exhibits topological defects in the form of vortices. They tend to\norganize into vortex lines that bear close analogies with global cosmic\nstrings. Therefore, this model serves as a testbed for studying the dynamics of\ntopological defects. It undergoes a second order phase transition, hence it is\nappropriate for investigating the Kibble-Zurek mechanism. In this regard, we\nexplore the persistence of topological defects when the temperature is rapidly\nreduced from above to below the critical temperature; this cooling (or\n\"quenching\") process takes the system out of equilibrium. We probe a wide range\nof inverse cooling rates $\\tau_{\\rm Q}$ and final temperatures, employing\ndistinct Monte Carlo algorithms. The results consistently show that the density\nof persisting topological defects follows a power-law in $\\tau_{\\rm Q}$, in\nagreement with Zurek's conjecture. On the other hand, at this point our results\ndo not confirm Zurek's prediction for the exponent in this power-law, but its\nfinal test is still under investigation.",
        "positive": "Simplicial Gravity in Dimension Greater than Two: We consider two issues in the DT model of quantum gravity. First, it is shown\nthat the triangulation space for D>3 is dominated by triangulations containing\na single singular (D-3)-simplex composed of vertices with divergent dual\nvolumes. Second we study the ergodicity of current simulation algorithms.\nResults from runs conducted close to the phase transition of the\nfour-dimensional theory are shown. We see no strong indications of ergodicity\nbr eaking in the simulation and our data support recent claims that the\ntransition is most probably first order. Furthermore, we show that the critical\nproperties of the system are determined by the dynamics of remnant singular\nvertices."
    },
    {
        "anchor": "The hadronic vacuum polarization with twisted boundary conditions: The leading-order hadronic contribution to the anomalous magnetic moment of\nthe muon is given by a weighted integral over the subtracted hadronic vacuum\npolarization. This integral is dominated by euclidean momenta of order the muon\nmass which are not available on current lattice volumes with periodic boundary\nconditions. Twisted boundary conditions can in principle help access momenta of\nany size even in a finite volume. We investigate the implementation of twisted\nboundary conditions both numerically (using all-mode averaging for improved\nstatistics) and analytically, and present our initial results.",
        "positive": "Zero of the discrete beta function in SU(3) lattice gauge theory with\n  color sextet fermions: We have carried out a Schrodinger functional (SF) calculation for the SU(3)\nlattice gauge theory with two flavors of Wilson fermions in the sextet\nrepresentation of the gauge group. We find that the discrete beta function,\nwhich governs the change in the running coupling under a discrete change of\nspatial scale, changes sign when the SF renormalized coupling is in the\nneighborhood of g^2=2.0. The simplest explanation is that the theory has an\ninfrared-attractive fixed point, but more complicated possibilities are allowed\nby the data. While we compare rescalings by factors of 2 and 4/3, we work at a\nsingle lattice spacing."
    },
    {
        "anchor": "BKT phase transitions in strongly coupled 3D Z(N) LGT at finite\n  temperature: We investigate, both analytically and numerically, the phase diagram of\nthree-dimensional Z(N) lattice gauge theories at finite temperature for N > 4.\nThese models, in the strong coupling limit, are equivalent to a generalized\nversion of vector Potts models in two dimension, with Polyakov loops playing\nthe role of Z(N) spins. It is argued that the effective spin models have two\nphase transitions of infinite order (i.e. BKT). Using a cluster algorithm we\nconfirm this conjecture, locate the position of the critical points and extract\nvarious critical indices.",
        "positive": "Partial Restoration of Flavor Symmetry for Chiral Staggered Fermions: At non-zero lattice spacing the flavor symmetry of staggered fermions is\nbroken to a discrete subgroup. We show that in the chiral limit the flavor\nsymmetry of the pion effective Lagrangian enlarges to an SO(4) subgroup of the\ncontinuum SU(4) symmetry. This provides an explanation for observed\ndegeneracies in the pion spectrum."
    },
    {
        "anchor": "Infrared Behavior of the Gluon Propagator on a Large Volume Lattice: The first calculation of the gluon propagator using an order a^2 improved\naction with the corresponding order a^2 improved Landau gauge fixing condition\nis presented. The gluon propagator obtained from the improved action and\nimproved Landau gauge condition is compared with earlier unimproved results on\nsimilar physical lattice volumes of 3.2^3 \\times 6.4 fm^4. We find agreement\nbetween the improved propagator calculated on a coarse lattice with lattice\nspacing a = 0.35 fm and the unimproved propagator calculated on a fine lattice\nwith spacing a = 0.10 fm. This motivates us to calculate the gluon propagator\non a coarse large-volume lattice 5.6^3 \\times 11.2 fm^4. The infrared behavior\nof previous studies is confirmed in this work. The gluon propagator is enhanced\nat intermediate momenta and suppressed at infrared momenta. Therefore the\nobserved infrared suppression of the Landau gauge gluon propagator is not a\nfinite volume effect.",
        "positive": "Improved $V_{cs}$ determination using precise lattice QCD form factors\n  for $D \\rightarrow K \\ell \u03bd$: We provide a 0.8\\%-accurate determination of $V_{cs}$ from combining\nexperimental results for the differential rate of $D \\rightarrow K$\nsemileptonic decays with precise form factors that we determine from lattice\nQCD. This is the first time that $V_{cs}$ has been determined with an accuracy\nthat allows its difference from 1 to be seen. Our lattice QCD calculation uses\nthe Highly Improved Staggered Quark (HISQ) action for all valence quarks on\ngluon field configurations generated by the MILC collaboration that include the\neffect of $u$, $d$, $s$ and $c$ HISQ quarks in the sea. We use eight gluon\nfield ensembles with five values of the lattice spacing ranging from 0.15 fm to\n0.045 fm and include results with physical $u/d$ quarks for the first time. Our\ncalculated form factors cover the full $q^2$ range of the physical decay\nprocess and enable a Standard Model test of the shape of the differential decay\nrate as well as the determination of $V_{cs}$ from a correlated weighted\naverage over $q^2$ bins. We obtain $|V_{cs}|=\n0.9663(53)_{\\text{latt}}(39)_{\\text{exp}}(19)_{\\eta_{EW}}(40)_{\\text{EM}}$,\nwhere the uncertainties come from lattice QCD, experiment, short-distance\nelectroweak and electromagnetic corrections, respectively. This last\nuncertainty, neglected for $D \\rightarrow K \\ell \\nu$ hitherto, now needs\nattention if the uncertainty on $V_{cs}$ is to be reduced further. We also\ndetermine $V_{cs}$ values in good agreement using the measured total branching\nfraction and the rates extrapolated to $q^2=0$. Our form factors enable tests\nof lepton flavour universality violation. We find the ratio of branching\nfractions for $D^0 \\rightarrow K^-$ with $\\mu$ and $e$ in the final state to be\n$R_{\\mu/e}=0.9779(2)_{\\text{latt}}(50)_{\\mathrm{EM}}$ in the Standard Model,\nwith the uncertainty dominated by that from electromagnetic corrections."
    },
    {
        "anchor": "Nucleon Axial Form Factor from Lattice QCD: Results for the isovector axial form factors of the proton from a lattice QCD\ncalculation are presented for both point-split and local currents. They are\nobtained on a quenched $16^{3} \\times 24$ lattice at $\\beta= 6.0$ with Wilson\nfermions for a range of quark masses from strange to charm. We determine the\nfinite lattice renormalization for both the local and point-split currents of\nheavy quarks. Results extrapolated to the chiral limit show that the $q^2$\ndependence of the axial form factor agrees reasonably well with experiment. The\naxial coupling constant $g_A$ calculated for the local and the point-split\ncurrents is about 6\\% and 12\\% smaller than the experimental value\nrespectively.",
        "positive": "Role of the Wilson mass parameter in the overlap Dirac topological\n  charge density: The negative Wilson mass parameter is an input parameter to the overlap Dirac\noperator. We examine the extent to which the topological charge density,\nrevealed by the overlap definition, depends on the value of the negative Wilson\nmass. A strong dependence is observed, which can be correlated with the\ntopological charge density obtained from the gluonic definition, with a\nvariable number of stout-link smearing sweeps. The results indicate that the\nfreedom typically associated with fat-link fermion actions, through the number\nof smearing sweeps, is also present in the overlap formalism, through the\nfreedom in the Wilson mass parameter."
    },
    {
        "anchor": "Machine Learning of Thermodynamic Observables in the Presence of Mode\n  Collapse: Estimating the free energy, as well as other thermodynamic observables, is a\nkey task in lattice field theories. Recently, it has been pointed out that deep\ngenerative models can be used in this context [1]. Crucially, these models\nallow for the direct estimation of the free energy at a given point in\nparameter space. This is in contrast to existing methods based on Markov chains\nwhich generically require integration through parameter space. In this\ncontribution, we will review this novel machine-learning-based estimation\nmethod. We will in detail discuss the issue of mode collapse and outline\nmitigation techniques which are particularly suited for applications at finite\ntemperature.",
        "positive": "Non-perturbative Methods in Modal Field Theory: Several issues in the modal approach to quantum field theory are discussed.\nWithin the formalism of spherical field theory, differential renormalization is\npresented and shown to result in a finite number of renormalization parameters.\nComputations of the massless Thirring model in 1+1 dimensions are presented\nusing this approach.\n  Diagonalization techniques in periodic field theory are demonstrated. Issues\nof very large Hilbert spaces are considered and several approaches are\npresented. The quasi sparse eigenvector (QSE) approach takes advantage of the\nrelatively small number of basis states that typically contribute significantly\nto any particular eigenvector. Stochastic correction methods use Monte Carlo\ncalculations to calculate higher order corrections to the quasi sparse result.\n  The quasi sparse eigenvector method and stochastic error correction are\napplied to the Hubbard model. With U/t=4, the shift in the ground energy below\nthe U=0 value is found to within 1% for the 8x8 Hubbard model with 25/64\nfilling."
    },
    {
        "anchor": "Deconfinement and universality in the 3D U(1) lattice gauge theory at\n  finite temperature: study in the dual formulation: We study analytically and numerically the three-dimensional U(1) lattice\ngauge theory at finite temperature in the dual formulation. For an appropriate\ndisorder operator, we obtain the renormalization group equations describing the\ncritical behavior of the model in the vicinity of the deconfinement phase\ntransition. These equations are used to check the validity of the\nSvetitsky-Yaffe conjecture regarding the critical behavior of the lattice U(1)\nmodel. Furthermore, we perform numerical simulations of the model for $N_t = 1,\n2, 4, 8$ and compute, by a cluster algorithm, the dual correlation functions\nand the corresponding second moment correlation length. In this way we locate\nthe position of the critical point and calculate critical indices.",
        "positive": "Finite Volume Effects on the Extraction of Form Factors at Zero Momentum: Hadronic matrix elements that depend on momentum are required for numerous\nphenomenological applications. Probing the low-momentum regime is often\nproblematic for lattice QCD computations on account of the restriction to\nperiodic momentum modes. Recently a novel method has been proposed to compute\nmatrix elements at zero momentum, for which straightforward evaluation of the\nmatrix elements would otherwise yield a vanishing result. We clarify an\nassumption underlying this method, and thereby establish the theoretical\nframework required to address the associated finite volume effects. Using the\npion electromagnetic form factor as an example, we show how the charge radius\nand two higher moments can be calculated at zero momentum transfer, and\ndetermine the corresponding finite volume effects. These computations are\nperformed using chiral perturbation theory to account for modified infrared\nphysics, and can be generalized to ascertain finite volume effects for other\nhadronic matrix elements extracted at zero momentum."
    },
    {
        "anchor": "Calculation of $K \\to \u03c0\u03c0$ decay amplitudes with improved Wilson\n  fermion in 2+1 flavor lattice QCD: We present results for the $K\\to\\pi\\pi$ decay amplitudes for both the $\\Delta\nI=1/2$ and $3/2$ channels. This calculation is carried out on 480 gauge\nconfigurations in $N_f=2+1$ QCD generated over 12,000 trajectories with the\nIwasaki gauge action and non-perturbatively $O(a)$-improved Wilson fermion\naction at $a=0.091\\,{\\rm fm}$, $m_\\pi=280\\,{\\rm MeV}$ and $m_K=580\\,{\\rm MeV}$\non a $32^3\\times 64$ ($La=2.9\\,{\\rm fm}$) lattice. For the quark loops in the\nPenguin and disconnected contributions in the $I=0$ channel, the combined\nhopping parameter expansion and truncated solver techniques work very well for\nvariance reduction. We obtain, for the first time with a Wilson-type fermion\naction, that ${\\rm Re}A_0 = 60(36) \\times10^{ -8}\\,{\\rm GeV}$ and ${\\rm Im}A_0\n=-67(56) \\times10^{-12}\\,{\\rm GeV}$ for a matching scale $q^* =1/a$. The\ndependence on the matching scale is weak.",
        "positive": "Non-perturbative Renormalization of Four-Fermion Operators Relevant to\n  $B_K$ with Staggered Quarks: We present preliminary results of matching factors of the four-fermion\noperators relevant to $B_K$, which are obtained using the non-perturbative\nrenormalization (NPR) method in the RI-MOM scheme with HYP-smeared improved\nstaggered fermions. We use the MILC asqtad coarse ($a \\cong 0.12\\,$fm)\nensembles with $20^3 \\times 64$ geometry and $am_{\\ell}/am_s = 0.01/0.05$. We\ncompare NPR results with those of one-loop perturbative matching."
    },
    {
        "anchor": "Relation $Tr \u03b3_{5}= 0$ and the index theorem in lattice gauge\n  theory: The relation $Tr \\gamma_{5}= 0$ implies the contribution to the trace from\nunphysical (would-be) species doublers in lattice gauge theory. This statement\nis also true for the Pauli-Villars regularization in continuum theory. If one\ninsists on $Tr \\gamma_{5}= 0$, one thus inevitably includes unphysical states\nin the Hilbert space. If one truncates the trace to the contribution from\nphysical species only, one obtains $\\tilde{T}r \\gamma_{5} = n_{+} - n_{-}$\nwhich is equal to the Pontryagin index. A smooth continuum limit of $\\tilde{T}r\n\\gamma_{5} = Tr \\gamma_{5}(1-(a/2)D) = n_{+} - n_{-}$ for the Dirac operator\n$D$ satisfying the Ginsparg-Wilson relation leads to the natural treatment of\nchiral anomaly in continuum path integral. In contrast, the continuum limit of\n$Tr \\gamma_{5}= 0$ is not defined consistently. It is shown that the\nnon-decoupling of heavy fermions in the anomaly calculation is crucial to\nunderstand the consistency of the customary lattice calculation of anomaly\nwhere $Tr \\gamma_{5}= 0$ is used. We also comment on a closely related\nphenomenon in the analysis of the photon phase operator where the notion of\nindex and the modification of index by a finite cut-off play a crucial role.",
        "positive": "Omega baryon electromagnetic form factors from lattice QCD: We present results on the Omega baryon electromagnetic form factors using\nN_f= 2 + 1 dynamical domain-wall fermion configurations corresponding to a pion\nmass of about 330 MeV. We construct appropriate sequential sources for the\ndetermination of the two dominant form factors GE0 and GM1 as well as a\nsequential source that isolates the subdominant electric quadrupole form factor\nGE2. We calculate the Omega baryon magnetic moment, mu_omega, and electric\ncharge radius, <r_E0>^2, and compare to experiment, for the case of mu_omega,\nand to other lattice calculations."
    },
    {
        "anchor": "Continuous smearing of Wilson Loops: Continuum smearing was introduced in section 4.1 of JHEP03, 064 (2006) as a\nmeaningful continuum analogue of the well known set of lattice techniques by\nthe same name. Here we apply continuous smearing in continuous space-time to\nWilson loops in order to clarify what it does in the context of field theory\nand also in the context of the loop calculus of the Makeenko-Migdal equation.",
        "positive": "Chiral extrapolation of g_A with explicit Delta(1232) degrees of freedom: An updated and extended analysis of the quark mass dependence of the\nnucleon's axial vector coupling constant g_A is presented in comparison with\nstate-of-the-art lattice QCD results. Special emphasis is placed on the role of\nthe Delta(1232) isobar. It is pointed out that standard chiral perturbation\ntheory of the pion-nucleon system at order p^4 fails to provide an\ninterpolation between the lattice data and the physical point. In constrast, a\nversion of chiral effective field theory with explicit inclusion of the\nDelta(1232) proves to be successful. Detailed error analysis and convergence\ntests are performed. Integrating out the Delta(1232) as an explicit degree of\nfreedom introduces uncontrolled errors for pion masses m_pi >~ 300 MeV."
    },
    {
        "anchor": "Dirac eigenmodes at the QCD Anderson transition: Recently we found an Anderson-type localization-delocalization transition in\nthe QCD Dirac spectrum at high temperature. Using spectral statistics we\nobtained a critical exponent compatible with that of the corresponding Anderson\nmodel. Here we study the spatial structure of the eigenmodes both in the\nlocalized and the transition region. Based on previous studies in the Anderson\nmodel, at the critical point, the eigenmodes are expected to have a scale\ninvariant multifractal structure. We verify the scale invariance of Dirac\neigenmodes at the critical point.",
        "positive": "Dirac operator normality and chiral properties on the lattice: Normality in connection with $\\gamma_5$-hermiticity determines the basic\nchiral properties and rules. The Ginsparg-Wilson (GW) relation is one of the\nallowed constraints on the spectrum. Interrelations between features of the\nspectrum, the sum rule for chiral differences of real modes and contributions\nto the Ward identity are pointed out. The alternative chiral transformation of\nL\\\"uscher gives the same Ward identity as the usual one, in the global and in\nthe local case. Imposing normality on a general function of the hermitean\nWilson-Dirac (HWD) operator, inevitably leads at the same time to the Neuberger\noperator and to the GW relation. In this context also the case with zero\neigenvalues of the HWD operator is handled. The eigenvalue flows of the HWD\noperator obey a differential equation the characteristic features of the\nsolutions of which are discussed."
    },
    {
        "anchor": "A gauge invariant order parameter for monopole condensation in $QCD$\n  vacuum: In this paper we improve the existing order parameter for monopole\ncondensation in gauge theory vacuum, making it gauge-invariant from scratch and\nfree of the spurious infrared problems which plagued the old one. Computing the\nnew parameter on the lattice will unambiguously detect weather dual\nsuperconductivity is the mechanism for color confinement.\n  As a byproduct we relate confinement to the existence of a finite correlation\nlength in the gauge-invariant correlator of chromo-electric field strengths.",
        "positive": "Pseudoscalar-Meson Octet-Baryon Coupling Constants from two-flavor\n  Lattice QCD: We evaluate the pseudoscalar-meson octet-baryon coupling constants and the\ncorresponding axial charges in eight channels ($\\pi N\\N$, $\\pi\\Sigma\\Sigma$,\n$\\pi\\Lambda\\Sigma$, $K\\Lambda N$, $K \\Sigma N $, $\\pi\\Xi\\Xi$, $K\\Lambda\\Xi$ and\n$K\\Sigma\\Xi$) in lattice QCD with two flavors of dynamical quarks. The\nparameter $\\alpha\\equiv F/(F+D)$ representing the SU(3)-flavor symmetry is\ncomputed at each u,d-quark hopping parameter and at the flavor-SU(3) symmetric\npoint where the three quark flavors are degenerate at the physical $s$-quark\nmass. In particular, we obtain $\\alpha=0.395(6)$ at the SU(3) symmetric limit.\nThe quark-mass dependences of the coupling constants are obtained by changing\nthe $u$- and the $d$-quark masses and we find that the SU(3)-flavor symmetry is\nbroken by only a few percent at each quark-mass we employ."
    },
    {
        "anchor": "SU(2) Colour Fields Around Static Sources: First results of an ongoing high statistics study of the colour flux\ndistribution around static quark sources in SU(2) gauge theory are presented.\nThe flux tube profiles and widths have been investigated for several quark\nseparations at beta=2.5 and beta=2.74. The results are tested against Michael's\nsum rules.",
        "positive": "Toward the minimal realization of a light composite Higgs: Work in progress is reported on a particularly interesting gauge theory with\na fermion doublet in the two-index symmetric (sextet) representation of the\nSU(3) color gauge group. Extending previous studies we outline our strategy as\nwe investigate Goldstone dynamics and Electroweak scale setting from chiral\nsymmetry breaking ($\\chi$ SB), test the GMOR relation from the spectrum of the\nDirac operator and the related chiral condensate, begin to develop and test\nmixed action based improved analysis of $\\chi$ SB with new run plans at fixed\ntopology to cross over from the p-regime to the epsilon-regime of $\\chi$ SB,\ncontinue to pursue the light $0^{++}$ scalar and its relation to the dilaton,\nand probe the scale-dependent running coupling from the perturbative UV scale\nto the scale of chiral symmetry breaking. Our observations suggest that the\nmodel is very close to the conformal window and a light composite scalar,\nperhaps the Higgs impostor with or without dilaton-like interpretation, appears\nto emerge with $0^{++}$ quantum numbers. The lightest baryon of the model on\nthe 3 TeV scale has intriguing implications."
    },
    {
        "anchor": "Topology in the $SU(N_f)$ chiral symmetry restored phase of unquenched\n  QCD and axion cosmology: The axion is one of the more interesting candidates to make the dark matter\nof the universe, and the axion potential plays a fundamental role in the\ndetermination of the dynamics of the axion field. Moreover, the way in which\nthe $U(1)_A$ anomaly manifests itself in the chiral symmetry restored phase of\n$QCD$ at high temperature could be tested when probing the $QCD$ phase\ntransition in relativistic heavy ion collisions. With these motivations, we\ninvestigate the physical consequences of the survival of the effects of the\n$U(1)_A$ anomaly in the chiral symmetric phase of $QCD$, and show that the free\nenergy density is a singular function of the quark mass $m$, in the chiral\nlimit, and that the $\\sigma$ and $\\bar\\pi$ susceptibilities diverge in this\nlimit at any $T\\ge T_c$. We also show that the difference between the $\\bar\\pi$\nand $\\bar\\delta$ susceptibilities diverges in the chiral limit at any $T\\ge\nT_c$, a result that can be contrasted with the existing lattice calculations;\nand discuss on the generalization of these results to the $N_f\\ge 3$ model.",
        "positive": "Pion distribution amplitude at the physical point using the\n  leading-twist expansion of the quasi-distribution-amplitude matrix element: We present a lattice QCD determination of the distribution amplitude (DA) of\nthe pion and the first few Mellin moments from an analysis of the quasi-DA\nmatrix element within the leading-twist framework. We perform our study on a\nHISQ ensemble with $a=0.076$ fm lattice spacing with the Wilson-Clover valence\nquark mass tuned to the physical point. We analyze the ratios of pion quasi-DA\nmatrix elements at short distances using the leading-twist Mellin operator\nproduct expansion (OPE) at the next-to-leading order and the conformal OPE at\nthe leading-logarithmic order. We find a robust result for the first\nnon-vanishing Mellin moment $\\langle x^2 \\rangle = 0.287(6)(6)$ at a\nfactorization scale $\\mu=2$ GeV. We also present different Ans\\\"atze-based\nreconstructions of the $x$-dependent DA, from which we determine the\nperturbative leading-twist expectations for the pion electromagnetic and\ngravitational form-factors at large momentum transfers."
    },
    {
        "anchor": "Phase Structure of SU(2) Lattice Gauge Theory with Quantum Gravity: We investigate 4$d$ SU(2) lattice gauge theory with Regge--Einstein quantum\ngravity on a dynamically coupled Regge skeleton. To overview the phase diagram\nwe perform simulations on a small $2\\cdot 4^3$ system. Evidence for an\nentropy--dominated disordered, an entropy--dominated ordered and an\nill--defined region is presented.",
        "positive": "The static quark potential from the gauge invariant Abelian\n  decomposition: We investigate the relationship between colour confinement and topological\nstructures derived from the gauge invariant Abelian (Cho-Duan-Ge)\ndecomposition. This Abelian decomposition is made imposing an isometry on a\ncolour field $n$ which selects the Abelian direction; the principle novelty of\nour study is that we have defined this field in terms of the eigenvectors of\nthe Wilson Loop. This allows us to establish an equivalence between the path\nordered integral of the non-Abelian gauge fields with an integral over an\nAbelian restricted gauge field which is tractable both theoretically and\nnumerically in lattice QCD. By using Stokes' theorem, we can relate the Wilson\nLoop in terms of a surface integral over a restricted field strength, and show\nthat the restricted field strength may be dominated by topological structures,\nwhich occur when one of the parameters parametrising the colour field $n$ winds\nitself around a non-analyticity in the colour field. If they exist, these\nobjects will lead to an area law scaling for the Wilson Loop and provide a\nmechanism for quark confinement. We search for these structures in quenched\nlattice QCD. We perform the Abelian decomposition, and find that the restricted\nfield strength is dominated by peaks on the lattice. Wilson Loops containing\nthese peaks show a stronger area-Law and thus provide the dominant contribution\nto the string tension."
    },
    {
        "anchor": "The lower moments of nucleon structure functions in lattice QCD with\n  physical quark masses: We present results for the nucleon structure functions and form factors\nobtained from 2+1 flavor lattice QCD with physical light quark masses\n($m_{\\pi}=135$ MeV) in a large spatial extent of about 10 fm. Our calculations\nare performed with the PACS10 gauge configurations generated by the PACS\nCollaboration with the six stout-smeared ${\\mathscr{O}}(a)$ improved\nWilson-clover quark action and Iwasaki gauge action at $\\beta=1.82$ and $2.00$\ncorresponding to lattice spacings of $0.085$ fm and $0.064$ fm respectively.\nThe lower moments of structure functions, $\\langle x \\rangle_{u-d}$ and\n$\\langle x \\rangle_{\\Delta u - \\Delta d}$ given by the twist-2 operators being\nproperly renormalized, are evaluated in the $\\overline{\\rm MS}$ scheme at the\nrenormalization scale of 2 GeV only at $\\beta=1.82$, since the renormalization\nfactors at $\\beta=2.00$ have not yet determined nonperturbatively in the RI/MOM\nscheme. Instead, at two lattice spacings, we evaluate appropriate ratios of\n$g_{A}/g_{V}$ and $\\langle x \\rangle_{u-d}/\\langle x \\rangle_{\\Delta u -\\Delta\nd}$, which are not renormalized in the continuum limit. These quantities thus\ncan be directly compared with the experimental data without the\nrenormalization.",
        "positive": "Towards overcoming the Monte Carlo sign problem with tensor networks: The study of lattice gauge theories with Monte Carlo simulations is hindered\nby the infamous sign problem that appears under certain circumstances, in\nparticular at non-zero chemical potential. So far, there is no universal method\nto overcome this problem. However, recent years brought a new class of\nnon-perturbative Hamiltonian techniques named tensor networks, where the sign\nproblem is absent. In previous work, we have demonstrated that this approach,\nin particular matrix product states in 1+1 dimensions, can be used to perform\nprecise calculations in a lattice gauge theory, the massless and massive\nSchwinger model. We have computed the mass spectrum of this theory, its thermal\nproperties and real-time dynamics. In this work, we review these results and we\nextend our calculations to the case of two flavours and non-zero chemical\npotential. We are able to reliably reproduce known analytical results for this\nmodel, thus demonstrating that tensor networks can tackle the sign problem of a\nlattice gauge theory at finite density."
    },
    {
        "anchor": "Lattice QCD in Background Fields: Electromagnetic properties of hadrons can be computed by lattice simulations\nof QCD in background fields. We demonstrate new techniques for the\ninvestigation of charged hadron properties in electric fields. Our current\ncalculations employ large electric fields, motivating us to analyze chiral\ndynamics in strong QED backgrounds, and subsequently uncover surprising\nnon-perturbative effects present at finite volume.",
        "positive": "The spectrum of closed loops of fundamental flux in D = 3+1 SU(N) gauge\n  theories: We study the spectrum of closed flux tubes in four dimensional SU(N) gauge\ntheories. We do so by calculating the energies of the low lying states with the\nvariational technique (whose basis consists of about ~700 operators). We study\nstates of different values of angular momentum, transversal parity,\nlongitudinal parity, and longitudinal momentum, and compare the results with\neffective string theories (ESTs) such as the Nambu-Goto (NG) model. Most of our\nstates agree very well with the Nambu-Goto predictions and since most of our\nflux-tubes' lengths are outside the radius of convergence of the ESTs, then for\nsome states it is only the NG that predicts the spectrum well. This strongly\nsuggests that the ESTs can be re-summed. Nonetheless, there are a few states\n(all with negative parity and in the same representation of the lattice\nrotation group) that exhibit large deviations from the NG predictions; these\ndeviations might provide clues to the nature of the effective string theory\ndescribing the large-N QCD string."
    },
    {
        "anchor": "Erratum: Standard-model prediction for direct CP violation in\n  $K\\to\u03c0\u03c0$ decay: In this document we address an error discovered in the ensemble generation\nfor our calculation of the $I=0$ $K\\to\\pi\\pi$ amplitude (Phys. Rev. Lett. 115,\n212001 (2015), arXiv:1505.07863) whereby the same random numbers were used for\nthe two independent quark flavors, resulting in small but measurable\ncorrelations between gauge observables separated by 12 units in the\ny-direction. We conclude that the effects of this error are negligible compared\nto the overall errors on our calculation.",
        "positive": "Correlation function distributions for O(N) lattice field theories in\n  the disordered phase: Numerical computations in strongly-interacting quantum field theories are\noften performed using Monte-Carlo sampling methods. A key task in these\ncalculations is to estimate the value of a given physical quantity from the\ndistribution of stochastic samples that are generated using the Monte-Carlo\nmethod. Typically, the sample mean and sample variance are used to define the\nexpectation values and uncertainties of computed quantities. However, the\nMonte-Carlo sample distribution contains more information than these basic\nproperties and it is useful to investigate it more generally. In this work, the\nexact form of the probability distributions of two-point correlation functions\nat zero momentum in O(N) lattice field theories in the disordered phase and in\ninfinite volume are determined. These distributions allow for a robust\ninvestigation of the efficacy of the Monte-Carlo sampling procedure and are\nshown also to allow for improved estimators of the target physical quantity to\nbe constructed. The theoretical expectations are shown to agree with numerical\ncalculations in the O(2) model."
    },
    {
        "anchor": "Robustness of baryon-strangeness correlation and related ratios of\n  susceptibilities: Using quenched lattice QCD simulations we investigate the continuum limit of\nbaryon-strangeness correlation and other related conserved charge-flavour\ncorrelations for temperatures T_c<T\\le2T_c. By working with lattices having\nlarge temporal extents (N_\\tau=12, 10, 8, 4) we find that these quantities are\nalmost independent of the lattice spacing, i.e, robust. We also find that these\nquantities have very mild dependence on the sea quark mass and acquire values\nwhich are very close to their respective ideal gas limits. Our results also\nconfirm robustness of the Wroblewski parameter.",
        "positive": "Multibondic Cluster Algorithm: Inspired by the multicanonical approach to simulations of first-order phase\ntransitions we propose for $q$-state Potts models a combination of cluster\nupdates with reweighting of the bond configurations in the\nFortuin-Kastelein-Swendsen-Wang representation of this model. Numerical tests\nfor the two-dimensional models with $q=7, 10$ and $20$ show that the\nautocorrelation times of this algorithm grow with the system size $V$ as $\\tau\n\\propto V^\\alpha$, where the exponent takes the optimal random walk value of\n$\\alpha \\approx 1$."
    },
    {
        "anchor": "`t Hooft model on the Lattice: Lattice results are presented for the meson spectrum of 1+1 dimensional gauge\ntheory at large $N$, using the Twisted Eguchi-Kawai model. Comparison is made\nto the results obtained by `t Hooft in the light cone gauge.",
        "positive": "Nucleon electromagnetic form factors from lattice QCD using a nearly\n  physical pion mass: We present lattice QCD calculations of nucleon electromagnetic form factors\nusing pion masses $m_\\pi$ = 149, 202, and 254 MeV and an action with\nclover-improved Wilson quarks coupled to smeared gauge fields, as used by the\nBudapest-Marseille-Wuppertal collaboration. Particular attention is given to\nremoval of the effects of excited state contamination by calculation at three\nsource-sink separations and use of the summation and generalized\npencil-of-function methods. The combination of calculation at the nearly\nphysical mass $m_\\pi$ = 149 MeV in a large spatial volume ($m_\\pi L_s$ = 4.2)\nand removal of excited state effects yields agreement with experiment for the\nelectric and magnetic form factors $G_E(Q^2)$ and $G_M(Q^2)$ up to $Q^2$ = 0.5\nGeV$^2$."
    },
    {
        "anchor": "Hybrid Monte Carlo simulation on the graphene hexagonal lattice: One of the many remarkable properties of graphene is that in the low energy\nlimit the dynamics of its electrons can be effectively described by the\nmassless Dirac equation. This has prompted investigations of graphene based on\nthe lattice simulation of a system of 2-dimensional fermions on a square\nstaggered lattice. We demonstrate here how to construct the path integral for\ngraphene working directly on the graphene hexagonal lattice. For the nearest\nneighbor tight binding model interacting with a long range Coulomb interaction\nbetween the electrons, this leads to the hybrid Monte Carlo algorithm with no\nsign problem. The only approximation is the discretization of the Euclidean\ntime. So as we extrapolate to the time continuum limit, the exact tight binding\nsolution maybe found numerically to arbitrary precession on a finite hexagonal\nlattice. The potential for this approach is tested on a single hexagonal cell.",
        "positive": "Adding machine learning within Hamiltonians: Renormalization group\n  transformations, symmetry breaking and restoration: We present a physical interpretation of machine learning functions, opening\nup the possibility to control properties of statistical systems via the\ninclusion of these functions in Hamiltonians. In particular, we include the\npredictive function of a neural network, designed for phase classification, as\na conjugate variable coupled to an external field within the Hamiltonian of a\nsystem. Results in the two-dimensional Ising model evidence that the field can\ninduce an order-disorder phase transition by breaking or restoring the\nsymmetry, in contrast with the field of the conventional order parameter which\ncauses explicit symmetry breaking. The critical behavior is then studied by\nproposing a Hamiltonian-agnostic reweighting approach and forming a\nrenormalization group mapping on quantities derived from the neural network.\nAccurate estimates of the critical point and of the critical exponents related\nto the operators that govern the divergence of the correlation length are\nprovided. We conclude by discussing how the method provides an essential step\ntoward bridging machine learning and physics."
    },
    {
        "anchor": "Coordinate-space calculation of QED corrections to the hadronic vacuum\n  polarization contribution to $(g-2)_\u03bc$: As several lattice collaborations agree on the result for the window quantity\nof the hadronic vacuum polarization (HVP) contribution to $(g-2)_\\mu$, whilst\nbeing in tension with the calculation using the dispersive approach, further\neffort is needed in order to pin down the cause for this difference. Here we\nwant to focus on the isospin breaking corrections to the leading order HVP. In\nmany lattice applications, the photon propagator is treated stochastically;\nhowever, by analogy with the hadronic light-by-light contribution (HLbL) to\n$(g-2)_\\mu$, we suggest a coordinate-space approach to the HVP at\nnext-to-leading order. We present a calculation of the two diagrams of the\n(2+2) topology at unphysical pion mass, where we apply a Pauli-Villars\nregularization for the extra photon propagator in the diagram that is\nUV-divergent. We compare the UV-finite diagram to the pseudoscalar exchange\ncontributions calculated from a vector-meson dominance model.",
        "positive": "The topological susceptibility in finite temperature QCD and axion\n  cosmology: We study the topological susceptibility in 2+1 flavor QCD above the chiral\ncrossover transition temperature using Highly Improved Staggered Quark action\nand several lattice spacings, corresponding to temporal extent of the lattice,\n$N_\\tau=6,8,10$ and $12$. We observe very distinct temperature dependences of\nthe topological susceptibility in the ranges above and below $250$ MeV. While\nfor temperatures above $250$ MeV, the dependence is found to be consistent with\ndilute instanton gas approximation, at lower temperatures the fall-off of\ntopological susceptibility is milder. We discuss the consequence of our results\nfor cosmology wherein we estimate the bounds on the axion decay constant and\nthe oscillation temperature if indeed the QCD axion is a possible dark matter\ncandidate."
    },
    {
        "anchor": "Monte Carlo evaluation of the continuum limit of the two-point function\n  of the Euclidean free real scalar field subject to affine quantization: We study canonical and affine versions of the quantized covariant Euclidean\nfree real scalar field-theory on four dimensional lattices through the Monte\nCarlo method. We calculate the two-point function at small values of the bare\ncoupling constant and near the continuum limit at finite volume. Our\ninvestigation shows that affine quantization is able to give meaningful results\nfor the two-point function for which is not available an exact analytic result\nand therefore numerical methods are necessary.",
        "positive": "Properties of low-lying charmonia and bottomonia from lattice QCD + QED: The precision of lattice QCD calculations has been steadily improving for\nsome time and is now approaching, or has surpassed, the 1% level for multiple\nquantities. At this level QED effects, i.e. the fact that quarks carry electric\nas well as color charge, come into play. In this report we will summarise\nresults from the first lattice QCD+QED computations of the properties of\nground-state charmonium and bottomonium mesons by the HPQCD Collaboration."
    },
    {
        "anchor": "Going chiral: overlap versus twisted mass fermions: We compare the behavior of overlap fermions, which are chirally invariant,\nand of Wilson twisted mass fermions at full twist in the approach to the chiral\nlimit. Our quenched simulations reveal that with both formulations of lattice\nfermions pion masses of O(250 MeV) can be reached in practical applications.\nOur comparison is done at a fixed value of the lattice spacing a=0.123 fm. A\nnumber of quantities are measured such as hadron masses, pseudoscalar decay\nconstants and quark masses obtained from Ward identities. We also determine the\naxial vector renormalization constants in the case of overlap fermions.",
        "positive": "Learning Trivializing Flows in a $\u03c6^4$ theory from coarser lattices: The so-called trivializing flows were proposed to speed up Hybrid Monte Carlo\nsimulations, where the Wilson flow was used as an approximation of a\ntrivializing map, a transformation of the gauge fields which trivializes the\ntheory. It was shown that the scaling of the computational costs towards the\ncontinuum did not change with respect to HMC. The introduction of machine\nlearning tecniques, especially normalizing flows, for the sampling of lattice\ngauge theories has shed some hope on solving topology freezing in lattice QCD\nsimulations. In this talk I will present our work in a $\\phi^{4}$ theory using\nnormalizing flows as trivializing flows (given its similarity with the idea of\na trivializing map), training from a trivial distribution as well as from\ncoarser lattices, and study its scaling towards the continuum, comparing it\nwith standard HMC."
    },
    {
        "anchor": "Transfer matrices and lattice fermions at finite density: I discuss the connection between the Hamiltonian and path integral approaches\nfor fermionic fields. I show how the temporal Wilson projection operators\nappear naturally in a lattice action. I also carefully treat the insertion of a\nchemical potential term.",
        "positive": "Propagators of hot SU(2) gauge theory from 3d adjoint Higgs model: We study propagators of the lattice 3d adjoint Higgs model, considered as an\neffective theory of 4d SU(2) gauge theory at high temperature. The propagators\nare calculated in so-called lambda-gauges. From the long distance behaviour of\nthe propagators we extract the screening masses. It is shown that the pole\nmasses extracted from the propagators agree well with the screening masses\nobtained recently in finite temperature SU(2) theory. The gauge dependence of\nthe screening masses is also discussed."
    },
    {
        "anchor": "Two-flavor QCD correction to lepton magnetic moments at leading-order in\n  the electromagnetic coupling: We present a reliable nonperturbative calculation of the QCD correction, at\nleading order in the electromagnetic coupling, to the anomalous magnetic moment\nof the electron, muon, and tau leptons using two-flavor lattice QCD. We use\nmultiple lattice spacings, multiple volumes, and a broad range of quark masses\nto control the continuum, infinite-volume, and chiral limits. We examine the\nimpact of the commonly ignored disconnected diagrams and introduce a\nmodification to the previously used method that results in a well-controlled\nlattice calculation. We obtain 1.513(43) 10^(-12), 5.72(16) 10^(-8), and\n2.650(54) 10^(-6) for the leading-order two-flavor QCD correction to the\nanomalous magnetic moment of the electron, muon, and tau, respectively, each\naccurate to better than 3%.",
        "positive": "Meson Electromagnetic Form Factors from Lattice QCD: Lattice QCD can provide a direct determination of meson electromagnetic form\nfactors, making predictions for upcoming experiments at Jefferson Lab. The form\nfactors are a reflection of the bound-state nature of the meson and so these\ncalculations give information about how confinement by QCD affects meson\ninternal structure. The region of high squared (space-like) momentum-transfer,\n$Q^2$, is of particular interest because perturbative QCD predictions take a\nsimple form in that limit that depends on the meson decay constant. We\npreviously showed in\\cite{jonnaff} that, up to $Q^2$ of 6 $\\mathrm{GeV}^2$, the\nform factor for a `pseudo-pion' made of strange quarks was significantly larger\nthan the asymptotic perturbative QCD result and showed no sign of heading\ntowards that value at higher $Q^2$. Here we give predictions for real mesons,\nthe $K^+$ and $K^0$, in anticipation of JLAB results for the $K^+$ in the next\nfew years. We also give results for a heavier meson, the $\\eta_c$, up to $Q^2$\nof 25 $\\mathrm{GeV}^2$ for a comparison to perturbative QCD in a higher $Q^2$\nregime."
    },
    {
        "anchor": "The condensate for two dynamical chirally improved quarks in QCD: We compare the eigenvalue spectra of the Dirac operator from a simulation\nwith two mass degenerate dynamical chirally improved fermions with Random\nMatrix Theory. Comparisons with distribution of k-th eigenvalues (k=1,2) in\nfixed topological sectors (nu=0,1) are carried out using the Kolmogorov-Smirnov\ntest. The eigenvalue distributions are well described by the RMT predictions.\nThe match allows us to read off the quark condensate in the chiral limit\ndirectly. Correcting for finite size and renormalization we obtain a mean value\nof -(276 (11)(16) MeV)**3 in the MS-bar scheme.",
        "positive": "Strange Baryon Electromagnetic Form Factors and SU(3) Flavor Symmetry\n  Breaking: We study the nucleon, Sigma and cascade octet baryon electromagnetic form\nfactors and the effects of SU(3) flavor symmetry breaking from 2+1-flavor\nlattice calculations. We find that electric and magnetic radii are similar; the\nmaximum discrepancy is about 10%. In the pion-mass region we explore, both the\nquark-component and full-baryon moments have small SU(3) symmetry breaking. We\nextrapolate the charge radii and the magnetic moments using three-flavor\nheavy-baryon chiral perturbation theory (HBXPT). The systematic errors due to\nchiral and continuum extrapolations remain significant, giving rise to charge\nradii for $p$ and $\\Sigma^-$ that are 3--4 standard deviations away from the\nknown experimental ones. Within these systematics the predicted $\\Sigma^+$ and\n$\\Xi^-$ radii are 0.67(5) and 0.306(15) fm$^2$ respectively. When the\nnext-to-next-to-leading order of HBXPT is included, the extrapolated magnetic\nmoments are less than 3 standard deviations away from PDG values, and the\ndiscrepancy is possibly due to remaining chiral and continuum extrapolation\nerrors."
    },
    {
        "anchor": "SU(2) chiral perturbation theory low-energy constants from staggered 2+1\n  flavor simulations: We measure the pion mass and decay constant on ensembles generated by the\nWuppertal-Budapest Collaboration, and extract the NLO low-energy constants l_3\nand l_4 of SU(2) chiral perturbation theory. The data are generated in 2+1\nflavor simulations with Symanzik glue and 2-fold stout-smeared staggered\nfermions, with pion masses varying from 135 MeV to 400 MeV, lattice scales\nbetween 0.7 GeV and 2.0 GeV, and m_s kept at its physical value. Furthermore,\nby excluding the lightest mass points, we are able to test the reliability of\nSU(2) chPT as a tool to extrapolate towards the physical point from higher pion\nmasses.",
        "positive": "New Abelian-like monopoles and the dual Meissner effect: Violation of non-Abelian Bianchi identity can be regarded as $N^2-1$\nAbelian-like monopole currents in the continuum SU(N) QCD. Three Abelian-like\nmonopoles, when defined in SU(2) gluodynamics on the lattice \\`{a} la\nDeGrand-Toussaint, are shown to have the continuum limit with respect to the\ncolor-invariant monopole density and the effective monopole action. Since each\nAbelian-like monopole is not gauge invariant, we have introduced various\npartial gauge fixing for the purpose of reducing lattice artifact monopoles in\nthe thermalized vacuum. Here we investigate Abelian and monopole dominances and\nthe Abelian dual Meissner effects adopting the same gauges like the maximal\ncenter gauge (MCG) in comparison with the maximal Abelian gauge (MAG). Abelian\nand monopole contributions to the string tension in these gauges are observed\nto be a little smaller than the non-Abelian string tension. However, we find\nthat the monopole dominance is improved well when use is made of the block-spin\ntransformations with respect to Abelian-like monopoles. We find each electric\nfield is squeezed by the corresponding colored Abelian-like monopole in such\ngauges and the Abelian dual Meissner effect is observed independently for each\ncolor. Moreover, we confirm the dual Amp\\`{e}re's law in these new gauges as\nwell as in MAG. The SU(2) vacuum is shown to be near the border between the\ntype 1 and type 2 dual superconductors. The penetration length is almost equal\nfor the four gauge fixings and the vacuum type in MCG is almost the same value\nas the previous results. These results are consistent with the previous results\nsuggesting the continuum limit and the gauge-independence of Abelian monopoles."
    },
    {
        "anchor": "Glueball Spectroscopy on S^3: For SU(2) gauge theory on the three-sphere we implement the influence of the\nboundary of the fundamental domain, and in particular the $\\theta$-dependence,\non a subspace of low-energy modes of the gauge field. We construct a basis of\nfunctions that respect these boundary conditions and use these in a variational\napproximation of the spectrum of the lowest order effective hamiltonian.",
        "positive": "Charmonium-nucleon interactions from the time-dependent HAL QCD method: The charmonium-nucleon effective central interactions have been computed by\nthe time-dependent HAL QCD method. This gives an updated result of a previous\nstudy based on the time-independent method, which is now known to be\nproblematic because of the difficulty in achieving the ground-state saturation.\nWe discuss that the result is consistent with the heavy quark symmetry. No\nbound state is observed from the analysis of the scattering phase shift;\nhowever, this shall lead to a future search of the hidden-charm pentaquarks by\nconsidering channel-coupling effects."
    },
    {
        "anchor": "Gravitational Action Versus Entropy on Simplicial Lattices in Four\n  Dimensions: We investigate quantum gravity on simplicial lattices using Regge calculus\nwith special emphasize on the problem of the unbounded action. The role of the\nentropy for the path integral is discussed in detail. Our numerical results\nshow further evidence for the existence of an entropy dominated region with\nwell defined expectation values even for unbounded action. Analyses are\nperformed both for the standard regular triangulation of the 4-torus and for\nirregularly triangulated lattices obtained by insertion of vertices using\nbarycentric subdivision.",
        "positive": "Induced YM theory with auxiliary bosons: We study pure SU(N) lattice gauge theory with a plaquette weight factor given\nby an inverse determinant which can be written as an integral over auxiliary\nbosonic fields (modifying a proposal of Budczies and Zirnbauer). We derive\nconditions for the existence of a continuum limit and its equivalence to\nYang-Mills theory. Furthermore, we perturbatively compute the relation between\nthe coupling constants of the `induced' gauge action and the familiar Wilson\ngauge action using the background-field technique. The perturbative relation\nagrees well with numerical results for N=2 in three dimensions."
    },
    {
        "anchor": "Static Quark Potentials in Quantum Gravity: We present potentials between static charges from simulations of quantum\ngravity coupled to an SU(2) gauge field on $6^{3}\\times 4$ and $8^{3}\\times 4$\nsimplicial lattices. The action consists of the gravitational term given by\nRegge's discrete version of the Euclidean Einstein action and a gauge term\ngiven by the Wilson action, with coupling constants $m_{p}^{2}$ and $\\beta$\nrespectively. In the well-defined phase of the gravity sector where geometrical\nexpectation values are stable, we study the correlations of Polyakov loops and\nextract the corresponding potentials between a source and sink separated by a\ndistance $R$. We compare potentials on a flat simplicial lattice with those on\na fluctuating Regge skeleton. In the confined phase, the potential has a linear\nform while in the deconfined phase, a screened Coulombic behavior is found. Our\nresults indicate that quantum gravitational effects do not destroy confinement\ndue to non-abelian gauge fields.",
        "positive": "Simulation of Lattice QCD with Domain-Wall Fermions: Quantum Chromodynamics (QCD) is the fundamental theory for the interaction\nbetween quarks and gluons. It manifests as the short-range strong interaction\ninside the nucleus, and plays an important role in the evolution of the early\nuniverse, from the quark-gluon phase to the hadron phase. To solve QCD is a\ngrand challenge, since it requires very large-scale numerical simulations of\nthe discretized action of QCD on the 4-dimensional space-time lattice.\nMoreover, since quarks are relativistic fermions, the 5-th dimension is\nintroduced such that massless quarks with exact chiral symmetry can be realized\nat finite lattice spacing, on the boundaries of the 5-th dimension, the\nso-called domain-wall fermion (DWF). In this talk, I discuss how to simulate\nlattice QCD with DWF such that the chiral symmetry can be preserved optimally\nwith a finite extent in the 5-th dimension. I also outline the simulations\nwhich have been performing by the TWQCD Collaboration and present some recent\nphysical results."
    },
    {
        "anchor": "Applicability of Quasi-Monte Carlo for lattice systems: This project investigates the applicability of quasi-Monte Carlo methods to\nEuclidean lattice systems in order to improve the asymptotic error scaling of\nobservables for such theories. The error of an observable calculated by\naveraging over random observations generated from ordinary Monte Carlo\nsimulations scales like $N^{-1/2}$, where $N$ is the number of observations. By\nmeans of quasi-Monte Carlo methods it is possible to improve this scaling for\ncertain problems to $N^{-1}$, or even further if the problems are regular\nenough. We adapted and applied this approach to simple systems like the quantum\nharmonic and anharmonic oscillator and verified an improved error scaling of\nall investigated observables in both cases.",
        "positive": "Resolving Exceptional Configurations: In lattice QCD with Wilson fermions, exceptional configurations arise in the\nquenched approximation at small quark mass. The origin of these large\npreviously uncontrolled lattice artifacts is identified. A simple well-defined\nprocedure (MQA) is presented which removes the artifacts while preserving the\ncorrect continuum limit."
    },
    {
        "anchor": "Finite volume renormalization scheme for fermionic operators: We propose a new finite volume renormalization scheme. Our scheme is based on\nthe Gradient Flow applied to both fermion and gauge fields and, much like the\nSchr\\\"odinger functional method, allows for a nonperturbative determination of\nthe scale dependence of operators using a step-scaling approach. We give some\npreliminary results for the pseudo-scalar density in the quenched\napproximation.",
        "positive": "Exact Lattice Supersymmetry at Large N: Employing a novel type of non-commutative product in the Dirac-Kahler twisted\nsuperspace on a lattice, we formulate a field theoretically rigid framework of\nextended supersymmetry on a lattice. As a first example of this treatment, we\ncalculate one-loop (in some cases any loops) quantum corrections for a twisted\nWess-Zumino model with N \\times N hermitian matrix superfields on a two\ndimensional lattice. The calculations are entirely given in a lattice\nsuperfield framework. We report that the mass and the coupling constant are\nexactly protected from the radiative corrections at non-zero lattice spacing as\nfar as the planar diagrams are concerned, which implies the realization of\nexact lattice supersymmetry w.r.t. all the supercharges in the large-N limit."
    },
    {
        "anchor": "Computational methods for the fermion determinant and the link between\n  overlap and domain wall fermions: This paper reviews the most popular methods which are used in lattice QCD to\ncompute the determinant of the lattice Dirac operator: Gaussian integral\nrepresentation and noisy methods. Both of them lead naturally to matrix\nfunction problems. We review the most recent development in Krylov subspace\nevaluation of matrix functions. The second part of the paper reviews the formal\nrelationship and algebraic structure of domain wall and overlap fermions. We\nreview the multigrid algorithm to invert the overlap operator. It is described\nhere as a preconditioned Jacobi iteration where the preconditioner is the Schur\ncomplement of a certain block of the truncated overlap matrix.",
        "positive": "Gluon and Ghost Dynamics from Lattice QCD: The two point gluon and ghost correlation functions and the three gluon\nvertex are investigated, in the Landau gauge, using lattice simulations. For\nthe two point functions, we discuss the approach to the continuum limit looking\nat the dependence on the lattice spacing and volume. The analytical structure\nof the propagators is also investigated by computing the corresponding spectral\nfunctions using an implementation of the Tikhonov regularisation to solve the\nintegral equation. For the three point function we report results when the\nmomentum of one of the gluon lines is set to zero and discuss its implications."
    },
    {
        "anchor": "Non-Perturbative Renormalization of the Lattice Heavy Quark Classical\n  Velocity: We discuss the renormalization of the lattice formulation of the Heavy Quark\nEffective Theory (LHQET). In addition to wave function and composite operator\nrenormalizations, on the lattice the classical velocity is also renormalized.\nThe origin of this renormalization is the reduction of Lorentz (or O(4))\ninvariance to (hyper)cubic invariance. We present results of a new, direct\nlattice simulation of this finite renormalization, and compare the results to\nthe perturbative (one loop) result. The simulation results are obtained with\nthe use of a variationally optimized heavy-light meson operator, using an\nensemble of lattices provided by the Fermilab ACP-MAPS collaboration.",
        "positive": "Heavy meson chiral perturbation theory in finite volume: We study finite volume effects in heavy quark systems in the framework of\nheavy meson chiral perturbation theory for full, quenched, and partially\nquenched QCD. A novel feature of this investigation is the role played by the\nscales Delta and delta_s, where Delta is the mass difference between the\nheavy-light vector and pseudoscalar mesons of the same quark content, and\ndelta_s is the mass difference due to light flavour SU(3) breaking. The primary\nconclusion of this work is that finite volume effects arising from the\npropagation of Goldstone particles in the effective theory can be altered by\nthe presence of these scales. Since Delta varies significantly with the heavy\nquark mass, these volume effects can be amplified in both heavy and light quark\nmass extrapolations (interpolations). As an explicit example, we present\nresults for B parameters of neutral B meson mixing matrix elements and\nheavy-light decay constants to one-loop order in finite volume heavy meson\nchiral perturbation theory for full, quenched, and N_f=2+1 partially quenched\nQCD. Our calculation shows that for high-precision determinations of the\nphenomenologically interesting SU(3) breaking ratios, finite volume effects are\nsignificant in quenched and not negligible in partially quenched QCD, although\nthey are generally small in full QCD."
    },
    {
        "anchor": "Gauged O(n) spin models in one dimension: We consider a gauged O(n) spin model, n >= 2, in one dimension which contains\nboth the pure O(n) and RP(n-1) models and which interpolates between them. We\nshow that this model is equivalent to the non-interacting sum of the O(n) and\nIsing models. We derive the mass spectrum that scales in the continuum limit,\nand demonstrate that there are two universality classes, one of which contains\nthe O(n) and RP(n-1) models and the other which has a tuneable parameter but\nwhich is degenerate in the sense that it arises from the direct sum of the O(n)\nand Ising models.",
        "positive": "QCD Phase Transition with Strange Quark in Wilson Formalism for Fermions: The nature of QCD phase transition is studied with massless up and down\nquarks and a light strange quark, using the Wilson formalism for quarks on a\nlattice with the temporal direction extension $N_t=4$. We find that the phase\ntransition is first order in the cases of both about 150 MeV and 400 MeV for\nthe strange quark mass. These results together with those for three degenerate\nquarks suggest that QCD phase transition in nature is first order."
    },
    {
        "anchor": "Fermionic correlators and zero-momentum modes in quenched lattice QED: For the Lorentz gauge the influence of various Gribov gauge copies on the\nfermion propagator is investigated in quenched compact lattice QED. Within the\nCoulomb phase besides double Dirac sheets the zero-momentum modes of the gauge\nfields are shown to cause the propagator to deviate strongly from the\nperturbatively expected behaviour. The standard way to extract the fermion mass\nfails. The recently proposed zero-momentum Lorentz gauge is demonstrated to\ncure the problem.",
        "positive": "Critical flavour number of the Thirring model in three dimensions: The Thirring model is a four-fermion theory with a current-current\ninteraction and $U(2N)$ chiral symmetry. It is closely related to\nthree-dimensional QED and other models used to describe properties of graphene.\nIn addition it serves as a toy model to study chiral symmetry breaking. In the\nlimit of flavour number $N \\to 1/2$ it is equivalent to the Gross-Neveu model,\nwhich shows a parity-breaking discrete phase transition. The model was already\nstudied with different methods, including Dyson-Schwinger equations, functional\nrenormalisation group methods and lattice simulations. Most studies agree that\nthere is a phase transition from a symmetric phase to a spontaneously broken\nphase for a small number of fermion flavours, but no symmetry breaking for\nlarge $N$. But there is no consensus on the critical flavour number\n$N^\\text{cr}$ above which there is no phase transition anymore and on further\ndetails of the critical behaviour. Values of $N$ found in the literature vary\nbetween $2$ and $7$.\n  All earlier lattice studies were performed with staggered fermions. Thus it\nis questionable if in the continuum limit the lattice model recovers the\ninternal symmetries of the continuum model. We present new results from lattice\nMonte Carlo simulations of the Thirring model with SLAC fermions which exactly\nimplement all internal symmetries of the continuum model even at finite lattice\nspacing. If we reformulate the model in an irreducible representation of the\nClifford algebra, we find, in contradiction to earlier results, that the\nbehaviour for even and odd flavour numbers is very different: For even flavour\nnumbers, chiral and parity symmetry are always unbroken. For odd flavour\nnumbers parity symmetry is spontaneously broken below the critical flavour\nnumber $N_\\text{ir}^\\text{cr}=9$ while chiral symmetry is still unbroken."
    },
    {
        "anchor": "Classically Emulated Digital Quantum Simulation of the Schwinger Model\n  with Topological Term via Adiabatic State Preparation: We perform a digital quantum simulation of a gauge theory with a topological\nterm in Minkowski spacetime, which is practically inaccessible by standard\nlattice Monte Carlo simulations. We focus on $1+1$ dimensional quantum\nelectrodynamics with the $\\theta$-term known as the Schwinger model. We\nconstruct the true vacuum state of a lattice Schwinger model using adiabatic\nstate preparation which, in turn, allows us to compute an expectation value of\nthe fermion mass operator with respect to the vacuum. Upon taking a continuum\nlimit we find that our result in massless case agrees with the known exact\nresult. In massive case, we find an agreement with mass perturbation theory in\nsmall mass regime and deviations in large mass regime. We estimate\ncomputational costs required to take a reasonable continuum limit. Our results\nimply that digital quantum simulation is already useful tool to explore\nnon-perturbative aspects of gauge theories with real time and topological\nterms.",
        "positive": "Monte-carlo renormalization group study of gauged RP(2) spin models in\n  two dimensions: The 2D RP(2) gauge model is studied using the Monte-Carlo Renormalization\nGroup. We confirm the first-order transition reported by Solomon et al. (PL\n112B, (1982)) ending in a critical point associated with vorticity. We find\nevidence for a new renormalized trajectory which is responsible for a\ncross-over from the vortex dominated regime to the O(3) regime as the coupling\nis reduced. Near to the cross-over region a good signal for scaling will be\nobserved in RP(2) but this is illusory and is due to the proximity of the new\nrenormalized trajectory. We suggest that this is the origin of the\n`pseudo'-scaling observed Hasenbusch and Horgan (PR D53, (1996)). We find that\nthe continuum limit of RP(2) is controlled by the O(3) fixed point. It is\nunclear whether the continuum limit of the new renormalized trajectory can be\ntaken at the observed critical point."
    },
    {
        "anchor": "On the screening of the potential between adjoint sources in $QCD_3$: We calculate the potential between adjoint sources in $SU(2)$ pure gauge\ntheory in three dimensions. We investigate whether the potential saturates at\nlarge separations due to the creation of a pair of gluelumps, colour-singlet\nstates formed when glue binds to an adjoint source.",
        "positive": "Hyperon Physics from Lattice QCD: I review recent lattice calculations of hyperon physics, including hyperon\nspectroscopy, axial coupling constants, form factors and semileptonic decays."
    },
    {
        "anchor": "Window contributions to the muon hadronic vacuum polarization with\n  twisted-mass fermions: We present a lattice calculation of the Euclidean position-space windows\ncontributing to the leading-order hadronic vacuum polarization term of the muon\nanomalous magnetic moment $a_\\mu$. Short-, intermediate- and long-distance\nwindows are considered in order to isolate different scales sensitive to\nspecific integration ranges of experimental time-like data used in the R-ratio.\nBy adopting the same smooth window function introduced by the RBC and UKQCD\nCollaborations with width parameter $\\Delta = 0.15~\\rm fm$, for the\nisospin-symmetric, light, quark-connected component we get $a_\\mu^{\\rm SD} (ud)\n= 48.21\\,(80) \\cdot 10^{-10}$ , $a_\\mu^{\\rm W} (ud) = 202.2\\,(2.6) \\cdot\n10^{-10}$ and $a_\\mu^{\\rm LD} (ud) = 382.5\\,(11.7) \\cdot 10^{-10}$ in the\nshort- (SD), intermediate- (W) and long-distance (LD) time regions,\nrespectively, with $t_0 = 0.4~\\rm fm$ and $t_1 = 1.0~\\rm fm$. Our results are\nobtained using the gauge configurations generated by the Extended Twisted Mass\nCollaboration with $N_f=2+1+1$ dynamical quarks, at three values of the lattice\nspacing varying from 0.089 to 0.062 fm, at several lattice volumes and with\npion masses in the range $M_\\pi \\simeq 220 - 490~\\rm MeV$.",
        "positive": "Center vortex model for the infrared sector of Yang-Mills theory -\n  Topological Susceptibility: A definition of the Pontryagin index for SU(2) center vortex world-surfaces\ncomposed of plaquettes on a hypercubic lattice is constructed. It is used to\nevaluate the topological susceptibility in a previously defined random surface\nmodel for vortices, the parameters of which have been fixed such as to\nreproduce the confinement properties of SU(2) Yang-Mills theory. A prediction\nfor the topological susceptibility is obtained which is compatible with\nmeasurements of this quantity in lattice Yang-Mills theory."
    },
    {
        "anchor": "Freezing a Fluid Random Surface: We investigate a dynamically triangulated random surface action that consists\nof a gaussian term plus the modulus of the intrinsic scalar curvature. We find\nthat the flips are frozen out and the internal geometry is regularized as the\ncoefficient of the latter term is increased. Such a term thus provides a way of\ninterpolating between dynamically triangulated (ie fluid) and crystalline\nrandom surfaces.",
        "positive": "The glue-ball spectrum of pure percolation: We present a high-precision numerical study of 3D random percolation viewed\nas a confining gauge theory. Using large correlation matrices among multiform\nWilson loops we determine the low-lying masses in various spin channels."
    },
    {
        "anchor": "Baryon interactions from lattice QCD with physical masses -- Overview\n  and $S = 0, -4$ sectors --: Nuclear forces and hyperon forces are studied by lattice QCD. Simulations are\nperformed with (almost) physical quark masses, $m_\\pi \\simeq 146$ MeV and $m_K\n\\simeq 525$ MeV, where $N_f=2+1$ nonperturbatively ${\\cal O}(a)$-improved\nWilson quark action with stout smearing and Iwasaki gauge action are employed\non the lattice of $(96a)^4 \\simeq (8.1\\mbox{fm})^4$ with $a^{-1} \\simeq 2.3$\nGeV. In this report, we give the overview of the theoretical framework and\npresent the numerical results for two-nucleon forces ($S=0$) and two-$\\Xi$\nforces ($S=-4$). Central forces are studied in $^1S_0$ channel, and central and\ntensor forces are obtained in $^3S_1$-$^3D_1$ coupled channel analysis.",
        "positive": "The Chiral Critical Point in 3-Flavour QCD: We determine the second order endpoint of the line of first order phase\ntransitions, which occur in the light quark mass regime of 3-flavour QCD at\nfinite temperature, and analyze universal properties of this chiral critical\npoint. A detailed analysis of Binder cumulants and the joint probability\ndistributions of energy like and ordering-field like observables confirms that\nthe chiral critical point belongs to the universality class of the 3d Ising\nmodel. From a calculation with improved gauge and staggered fermion actions we\nestimate that the transition is first order for pseudo-scalar meson masses less\nthan about 200 MeV."
    },
    {
        "anchor": "The saga of rooted staggered quarks: I look at the rooting controversy from a historical point of view and review\nhow I have come to the conclusion that these simulations involving staggered\nquarks must be discarded.",
        "positive": "Beyond Thimbles: Sign-Optimized Manifolds for Finite Density: The sign problem of relativistic field theories at finite fermion chemical\npotential has been approached by deforming the domain of integration into\ncomplex field space. We present a method for selecting a deformed manifold of\nintegration which is a local maximum of the average phase, and demonstrate this\nmethod on the three-dimensional Thirring model. Finally, we compare the\nperformance of this method, in the heavy-dense limit, to direct integration on\nthe Lefschetz thimbles."
    },
    {
        "anchor": "Finite size scaling in CP(N-1) models: Finite size effects in Euclidean ${\\rm CP}^{N-1}$ models with periodic\nboundary conditions are investigated by means of the $1/N$ expansion and by\nMonte Carlo simulations. Analytic and numerical results for magnetic\nsusceptibility and correlation length are compared and found to agree for small\nvolumes. For large volumes a discrepancy is found and explained as an effect of\nthe physical bound state extension. The leading order finite size effects on\nthe Abelian string tension are computed and compared with simulations finding\nagreement. Finite size dependence of topological quantities is also discussed.",
        "positive": "Improved Gauge Actions on Anisotropic Lattices I: On anisotropic lattices with the anisotropy $\\xi=a_\\sigma/a_\\tau$ the\nfollowing basic parameters are calculated by perturbative method: (1) the\nrenormalization of the gauge coupling in spatial and temporal directions,\n$g_\\sigma$ and $g_\\tau$, (2) the $\\Lambda$ parameter, (3) the ratio of the\nrenormalized and bare anisotropy $\\eta=\\xi/\\xi_B$ and (4) the derivatives of\nthe coupling constants with respect to $\\xi$, $\\partial g_\\sigma^{-2}/\\partial\n\\xi$ and $\\partial g_\\tau^{-2}/\\partial \\xi$. We employ the improved gauge\nactions which consist of plaquette and six-link rectangular loops, $c_0 P(1\n\\times 1)_{\\mu \\nu} + c_1 P(1 \\times 2)_{\\mu \\nu}$. This class of actions\ncovers Symanzik, Iwasaki and DBW2 actions. The ratio $\\eta$ shows an impressive\nbehavior as a function of $c_{1}$, i.e.,$\\eta>1$ for the standard Wilson and\nSymanzik actions, while $\\eta<1$ for Iwasaki and DBW2 actions. This is\nconfirmed non-perturbatively by numerical simulations in weak coupling regions.\nThe derivatives $\\partial g^{-2}_{\\tau}/\\partial \\xi$ and $\\partial\ng^{-2}_{\\sigma}/\\partial \\xi$ also changes sign as $-c_{1}$ increases. For\nIwasaki and DBW2 actions they become opposite sign to those for standard and\nSymanzik actions. However, their sum is independent of the type of actions due\nto Karsch's sum rule."
    },
    {
        "anchor": "Magnetic monopole and confinement/deconfinement phase transition in\n  SU(3) Yang-Mills theory: We have proposed the non-Abelian dual superconductivity in SU(3) Yang-Mills\ntheory for the mechanism of quark confinement,and we presented the numerical\nevidences in preceding lattice conferences by using the proposed gauge link\ndecomposition to extract magnetic monopole in the gauge invariant way. In this\ntalk, we focus on the dual Meissner effects in view of the magnetic monopole in\nSU(3) Yang-Mills theory. We measure the chromoelectric and chromomagnetic flux\ndue to a pair of quark and antiquark source at finite temperature. Then, we\nmeasure the correlation function of Polyakov loops and Polyakov loop average at\nvarious temperatures, and investigate chromomagnetic monopole current induced\nby chromo-magnetic flux in both confinement and deconfinement phase. We will\ndiscuss the role of the chromoelectric monopole in confinement/deconfinement\nphase transition.",
        "positive": "Screening of heavy quark free energies at finite temperature and\n  non-zero baryon chemical potential: We analyze the dependence of heavy quark free energies on the baryon chemical\npotential (mu_b) in 2-flavour QCD using improved (p4) staggered fermions with a\nbare quark mass of m/T = 0.4. By performing a 6th order Taylor expansion in the\nchemical potential which circumvents the sign problem. The Taylor expansion\ncoefficients of colour singlet and colour averaged free energies are calculated\nand from this the expansion coefficients for the corresponding screening masses\nare determined. We find that for small mu_b the free energies of a static quark\nanti-quark pair decrease in a medium with a net excess of quarks and that\nscreening is well described by a screening mass which increases with increasing\nmu_b. The mu_b-dependent corrections to the screening masses are well described\nby perturbation theory for T > 2 T_c. In particular, we find for all\ntemperatures above T_c that the expansion coefficients for singlet and colour\naveraged screening masses differ by a factor 2."
    },
    {
        "anchor": "Improvement of the pion spectrum with HYP-smeared staggered fermions: We extend our previous study of taste-symmetry breaking using HYP-smeared\nstaggered fermions in two ways. First, we improve the statistics of a\ncomparison of unimproved and HYP-smeared staggered fermions on quenched\nlattices with $a\\approx 0.1 $fm. This allows us to obtain a signal for all pion\ntastes, rather than just a subset, and thus to make a complete comparison. In\naddition, it allows us to differentiate between wall and local sources. Second,\nwe compare HYP-smeared valence quarks to asqtad valence quarks on 2+1 flavor\nunquenched MILC lattices. We find that taste breaking is substantially reduced\nby HYP-smearing, bringing the size of this discretization effect (which is the\ndominant such effect with staggered fermions) down to the size expected\ngenerically for any fermion type.",
        "positive": "Towards the glueball spectrum of full QCD: We present first results on masses of the scalar and tensor glueballs as well\nas of the torelon from simulations of QCD with two light flavours of Wilson\nfermions. The gauge configurations of extent 16^3*32 at beta = 5.6 and kappa =\n0.156, 0.157 and 0.1575 have been generated as part of the SESAM collaboration\nprogramme. The present lattice resolutions correspond to 1/a = 2.0-2.3 GeV and\nratios m(pi)/m(rho) = 0.83, 0.76 and 0.71, respectively. Studies on larger\nlattice volumes and closer to the chiral limit are in progress."
    },
    {
        "anchor": "Scalar Glueball in Radiative $J/\u03c8$ Decay on Lattice: The form factors in the radiative decay of $J/\\psi$ to a scalar glueball are\nstudied within quenched lattice QCD on anisotropic lattices. The continuum\nextrapolation is carried out by using two different lattice spacings. With the\nresults of these form factors, the partial width of $J/\\psi$ radiatively\ndecaying into the pure gauge scalar glueball is predicted to be 0.35(8) keV,\nwhich corresponds to a branching ratio of 3.8(9)x10^{-3}. By comparing with the\nexperiments, out results indicate that f_0(1710) has a larger overlap with the\npure gauge glueball than other related scalar mesons.",
        "positive": "Topology, chiral and screening transitions at finite density in two\n  colour QCD: The behaviour of the topological susceptibility in QCD with two colours and 8\nflavours of quarks is studied at nonzero temperature on the lattice across the\nfinite density transition. It is shown that its signal drops at a\n(pseudo-)critical chemical potential mu_c. The Polyakov loop and the chiral\ncondensate undergo their transitions at the same value. Pauli blocking\nsupervenes at a value of the chemical potential larger than mu_c."
    },
    {
        "anchor": "Duality in Long-Range Ising Ferromagnets: It is proved that for a system of spins $\\sigma _i = \\pm 1$ having an\ninteraction energy $-\\sum K_{ij} \\sigma _i \\sigma _j $ with all the $K_{ij}$\nstrictly positive,one can construct a dual formulation by associating a dual\nspin $S_{ijk} = \\pm 1$ to each triplet of distinct sites $i,j$ and $k$. The\ndual interaction energy reads $-\\sum _{(ij)} D_{ij} \\prod _{k \\neq i,j}\nS_{ijk}$ with $tanh(K_{ij})\\ = \\ exp(-2D_{ij})$, and it is invariant under\nlocal symmetries. We discuss the gauge-fixing procedure, identities relating\naverages of order and disorder variables and representations of various\nquantities as integrals over Grassmann variables. The relevance of these\nresults for Polyakov's approach of the 3D Ising model is briefly discussed.",
        "positive": "$B \\rightarrow \u03c0\\ell \u03bd$ at zero recoil from lattice QCD with\n  physical $u/d$ quarks: The exclusive semileptonic decay $B \\rightarrow \\pi \\ell \\nu$ is a key\nprocess for the determination of the Cabibbo-Kobayashi-Maskawa matrix element\n$V_{ub}$ from the comparison of experimental rates as a function of $q^2$ with\ntheoretically determined form factors. The sensitivity of the form factors to\nthe $u/d$ quark mass has meant significant systematic uncertainties in lattice\nQCD calculations at unphysically heavy pion masses. Here we give the first\nlattice QCD calculations of this process for u/d quark masses going down to\ntheir physical values, calculating the $f_0$ form factor at zero recoil to 3\\%.\nWe are able to resolve a long-standing controversy by showing that the\nsoft-pion theorem result $f_0(q^2_{max}) = f_B/f_{\\pi}$ does hold as $m_{\\pi}\n\\rightarrow 0$. We use the Highly Improved Staggered Quark formalism for the\nlight quarks and show that staggered chiral perturbation theory for the\n$m_{\\pi}$ dependence is almost identical to continuum chiral perturbation\ntheory for $f_0$, $f_B$ and $f_{\\pi}$. We also give results for other processes\nsuch as $B_s \\rightarrow K \\ell \\nu$."
    },
    {
        "anchor": "Equivalence of lattice operators and graph matrices: We explore the relationship between lattice field theory and graph theory,\nplacing special emphasis on the interplay between Dirac and scalar lattice\noperators and matrices within the realm of spectral graph theory. Beyond\ndelving into fundamental concepts of spectral graph theory, such as adjacency\nand Laplacian matrices, we introduce a novel matrix named as \"anti-symmetrized\nadjacency matrix\", specifically tailored for cycle digraphs ($T^1$ lattice) and\nsimple directed paths ($B^1$ lattice). The nontrivial relation between graph\ntheory matrices and lattice operators shows that the graph Laplacian matrix\nmirrors the lattice scalar operator and the Wilson term in lattice fermions,\nwhile the anti-symmetrized adjacency matrix, along with its extensions to\nhigher dimensions, are equivalent to naive lattice Dirac operators. Building\nupon these connections, we provide rigorous proofs for two key assertions: (i)\nThe count of zero-modes in a free lattice scalar operator coincides with the\nzeroth Betti number of the underlying graph (lattice). (ii) The maximum count\nof Dirac zero-modes in a free lattice fermion operator is equivalent to the\ncumulative sum of all Betti numbers when the $D$-dimensional graph results from\na cartesian product of cycle digraphs ($T^1$ lattice) and simple directed paths\n($B^1$ lattice).",
        "positive": "Twisted space-time reduced model of large N QCD with two adjoint Wilson\n  fermions: The space-time reduced model of large N QCD with two adjoint Wilson fermions\nis constructed by applying the symmetric twist boundary conditions with\nnon-vanishing flux $k$. For large but finite $N=L^2$, the model should behave\nas the large N version of the ordinary lattice gauge model on a $V=L^4$\nspace-time volume. We perform a comparison of the $N$ dependence of several\nquantities in this model and in the $k$=0 model (corresponding to periodic\nboundary conditions). Although the Z$^4$(N) symmetry seems unbroken in all\ncases, the N-dependence analysis favours the use of the same values of $k$ and\n$L$ for which the symmetry is also unbroken in the pure gauge case. In\nparticular, the $k=0$ model, studied recently by several authors, shows a large\nand irregular dependence on $N$ within our region of parameters. This makes\nthis reduced model very impractical for extracting physical information about\nthe large N lattice theory. On the contrary, the model for $N=289=17^2$ and\nlarge enough $k$ gives consistent results, even for extended observables as\nWilson loops $W(R,T)$ up to $R,T$=8, matching the expected behaviour for the\nlattice model with a $17^4$ space-time volume."
    },
    {
        "anchor": "Running Coupling in pure gauge theories using the Schr\u00f6dinger\n  functional: Schr\\\"odinger functional, the propagation kernel for going from some field\nconfiguration at time $x^0=0$ to some other configuration at $x^0=T$, is used\nto define a running coupling, $\\bar g^2(L)$, at a length scale, $L$, in pure\ngauge theories. Using a lattice formulation and finite size scaling techniques,\nthis running coupling is calculated non-perturbatively in the continuum for a\nwide range of $L$, that extends from the perturbative scales to\nnon-perturbative scales, for the specific case of pure SU(2) gauge theory.",
        "positive": "Performance Optimization of Baryon-block Construction in the Stochastic\n  LapH Method: Implementations of measurement kernels in high-level Lattice QCD frameworks\nenable rapid prototyping, but can leave hardware capabilities significantly\nunderutilized. This is an acceptable tradeoff if the time spent in unoptimized\nroutines is generally small. The computational cost of modern spectroscopy\nprojects however can be comparable to or even exceed the cost of generating\ngauge configurations and computing solutions of the Dirac equation. One such\nkey kernel in the stochastic LapH method is the computation of baryon blocks;\nwe discuss several implementation strategies and achieve a 7.2x speedup over\nthe current implementation on a system with Intel(R) Xeon(R) Platinum 8358\nprocessors, formerly Ice Lake."
    },
    {
        "anchor": "Dynamical overlap fermions in the epsilon-regime: We report on the two-flavor QCD simulation in the epsilon-regime using the\noverlap fermion formulation. Sea quark mass is reduced to ~ 2 MeV on a 16^3x32\nlattice with the lattice spacing ~ 0.11fm. Topological charge is fixed at Q=0.\nWe compare the eigenvalue distribution of the overlap-Dirac operator with the\nprediction of the chiral random matrix theory. Preliminary results on meson\ncorrelators are also reported.",
        "positive": "New insight into the Berezinskii-Kosterlitz-Thouless phase transition: We investigate the 2d XY model by using the constraint angle action, which\nbelongs to the class of topological lattice actions. These actions violate\nimportant features usually demanded for a lattice action, such as the correct\nclassical continuum limit and the applicability of perturbation theory.\nNevertheless, they still lead to the same universal quantum continuum limit and\nshow excellent scaling behavior. By using the constraint angle action we gain\nnew insight into the Berezinskii-Kosterlitz-Thouless phase transition of the 2d\nXY model. This phase transition is of special interest since it is one of the\nfew examples of a phase transition beyond second order. It is of infinite order\nand therefore an essential phase transition. In particular, we observe an\nexcellent scaling behavior of the helicity modulus, which characterizes this\nphase transition. We also observe that the mechanism of (un)binding\nvortex--anti-vortex pairs follows the usual pattern, although free vortices do\nnot require any energy in the formulation of the 2d XY model using the\nconstraint angle action."
    },
    {
        "anchor": "The effective potential and the renormalisation group: We discuss renormalisation group improvement of the effective potential both\nin general and in the context of $O(N)$ scalar $\\p^4$ and the Standard Model.\nIn the latter case we find that absolute stability of the electroweak vacuum\nimplies that $m_H\\geq 1.95m_t-189~GeV$, for $\\as (M_Z) = 0.11$. We point out\nthat the lower bound on $m_H$ {\\it decreases\\/} if $\\as (M_Z)$ is increased.",
        "positive": "Composite dynamics in Sp($2N$) gauge theories: Sp($2N$) gauge theories with fermonic matter provide an ideal laboratory to\nbuild extensions of the standard model based on novel composite dynamics.\nExamples include composite Higgs along with top partial compositeness and\ncomposite dark matter. Without fermions, their study also complements those\nbased on SU($N_c$) gauge theories with which they share a common sector in the\nlarge $N_c=2N$ limit. We report on our recent progress in the numerical studies\nof Sp($2N$) gauge theories discretised on a four-dimensional Euclidean lattice.\nIn particular, we present preliminary results for the low-lying mass spectra of\nmesons and chimera baryons in the theories with $N=2$. We also compute the\ntopological susceptibility for various values of $N$, extrapolate the results\nto the large $N$ limit, and discuss certain universal properties in Yang-Mills\ntheories."
    },
    {
        "anchor": "From string breaking to quarkonium spectrum: We present a preliminary computation of potentials between two static quarks\nin $n_f=2$ QCD with O(a) improved Wilson fermions. We explore different\nsmearing choices (HYP, HYP2 and APE) and their effect on the signal to noise\nratio in the computed static potentials. This is a part of a larger effort\nconcerning, at first, a precise computation of the QCD string breaking\nparameters and their subsequent utilization for the recent approach based on\nBorn-Oppenheimer approximation (Bicudo et al. 2020 \\cite{Bicudo:2019ymo}) to\nstudy quarkonium resonances and bound states.",
        "positive": "Properties of Interfaces in the two and three dimensional Ising Model: To investigate order-order interfaces, we perform multimagnetical Monte Carlo\nsimulations of the $2D$ and $3D$ Ising model. Following Binder we extract the\ninterfacial free energy from the infinite volume limit of the magnetic\nprobability density. Stringent tests of the numerical methods are performed by\nreproducing with high precision exact $2D$ results. In the physically more\ninteresting $3D$ case we estimate the amplitude $F^s_0$ of the critical\ninterfacial tension $F^s = F^s_0 t^\\mu$ to be $F^s_0 = 1.52 \\pm 0.05$. This\nresult is in good agreement with a previous MC calculation by Mon, as well as\nwith experimental results for related amplitude ratios. In addition, we study\nin some details the shape of the magnetic probability density for temperatures\nbelow the Curie point."
    },
    {
        "anchor": "Strong coupling methods in QCD thermodynamics: For a long time, strong coupling expansions have not been applied\nsystematically in lattice QCD thermodynamics, in view of the succes of\nnumerical Monte Carlo studies. The persistent sign problem at finite\nbaryo-chemical potential, however, has motivated investigations using these\nmethods, either by themselves or combined with numerical evaluations, as a\nroute to finite density physics. This article reviews the strategies, by which\na number of qualitative insights have been attained, notably the emergence of\nthe hadron resonance gas or the identification of the onset transition to\nbaryon matter in specific regions of the QCD parameter space. For the simpler\ncase of Yang-Mills theory, the deconfinement transition can be determined\nquantitatively even in the scaling region, showing possible prospects for\ncontinuum physics.",
        "positive": "A Swendsen-Wang update algorithm for the Symanzik improved sigma model: We study a generalization of Swendsen-Wang algorithm suited for Potts models\nwith next-next-neighborhood interactions. Using the embedding technique\nproposed by Wolff we test it on the Symanzik improved bidimensional non-linear\n$\\sigma$ model. For some long range observables we find a little slowing down\nexponent ($z \\simeq 0.3$) that we interpret as an effect of the partial\nfrustration of the induced spin model."
    },
    {
        "anchor": "Binding Energies in Nonrelativistic Field Theories: Relativistic corrections communicate the binding energy of a bound state to\nits kinetic mass. This mechanism is reviewed and used to explain anomalous\nresults of Collins, Edwards, Heller, and Sloan (hep-lat/9512026), which\ncompared rest and kinetic masses of heavy-light mesons and quarkonia.",
        "positive": "Testing the hadro-quarkonium model on the lattice: Recently the LHCb experiment found evidence for the existence of two exotic\nresonances consisting of $c\\bar{c}uud$ quarks. Among the possible\ninterpretations is the hadro-charmonium model, in which charmonium is bound\n\"within\" a light hadron. We test this idea on CLS $N_f$=2+1 lattices using the\nstatic formulation for the heavy quarks. We find that the static potential is\nmodified by the presence of a hadron such that it becomes more attractive. The\neffect is of the order of a few MeV."
    },
    {
        "anchor": "Lattice QCD review of charmonium and open-charm spectroscopy: Lattice QCD results on the spectroscopy of charmonium(like) states and open\ncharm mesons are reviewed. Near-threshold states X(3872) and D_{s0}^*(2317)\nwere treated rigorously for the first time and the searches for Z_c^+(3900),\nX(4140) and $cc\\bar u\\bar d$ were carried out. The first simulations of the\nresonances with charm quarks have been performed, including the determination\nof their strong decay widths. Spectroscopy of highly excited charmed,\ncharmonium and hybrid states has been calculated.",
        "positive": "Vortex Structure vs. Monopole Dominance in Abelian-Projected Gauge\n  Theory: We find that Polyakov lines, computed in abelian-projected SU(2) lattice\ngauge theory in the confined phase, have finite expectation values for lines\ncorresponding to two units of the abelian electric charge. This means that the\nabelian-projected lattice has at most Z(2), rather than U(1), global symmetry.\nWe also find a severe breakdown of the monopole dominance approximation, as\nwell as positivity, in this charge-2 case. These results imply that the\nabelian-projected lattice is not adequately represented by a monopole Coulomb\ngas; the data is, however, consistent with a center vortex structure. Further\nevidence is provided, in lattice Monte Carlo simulations, for collimation of\nconfining color-magnetic flux into vortices."
    },
    {
        "anchor": "Recent results on light hadron and quark masses: Recent results for the spectrum of light hadrons provide clear evidence for\nthe failure of quenched QCD and encouraging signs that simulations with\ndynamical sea quarks rectify some of the discrepancies, although string\nbreaking has not yet been observed. The use of perturbation theory to match\nlattice quark masses to continuum schemes remains questionable, but\nnon-perturbative methods are poised to remove this uncertainty. The inclusion\nof dynamical sea quarks substantially reduces estimates of the light quark\nmasses. New results for the lightest glueball and the lightest exotic hybrid\nstate provide useful input to phenomenology, but still have limited or no\ntreatment of mixing. The $O(a)$-improved Wilson quark action is\nwell-established in quenched QCD for $\\beta\\geq 5.7$, with most parameters\nobtainable non-perturbatively, in which range scaling violations are small.\nProgress has also been made with high-order improvement schemes for both Wilson\nand staggered quarks.",
        "positive": "Gauge Theory in d=2+1 at High Temperature: Z_N interface: We calculate on the lattice the interface tension in the SU(2) pure gauge\ntheory in d=2+1 at high temperature. The result is compared to the perturbative\nprediction. The agreement confirms applicability of the perturbation theory in\nthis case."
    },
    {
        "anchor": "Spectroscopy of mesons with bottom quarks: Preliminary results for the spectra of excited and exotic bottom mesons are\npresented. The calculation on a dynamical anisotropic ensemble exploits\ndistillation, enabling the use of a large basis of interpolating operators\nincluding those proportional to the gluonic field strength which are relevant\nfor hybrid states. A comparison of results with similar calculations in the\nlight and charm sectors is discussed.",
        "positive": "$K\\to\u03c0\u03c0$ decay matrix elements at the physical point with periodic\n  boundary conditions: We calculate $K\\to\\pi\\pi$ matrix elements using periodic boundary conditions\nas an independent calculation from our previous study with G-parity boundary\nconditions. We present our preliminary results for $K\\to\\pi\\pi$ three-point\nfunctions and matrix elements on a $24^3, a^{-1} = 1$~GeV, $2+1$-flavor\nM\\\"obius DWF ensemble at physical pion and kaon masses generated by the RBC and\nUKQCD collaborations and discuss the prospect for high-precision computation of\n$\\varepsilon'$ with periodic boundary conditions."
    },
    {
        "anchor": "Non-perturbative renormalization of Nf=2+1 QCD with Schroedinger\n  functional scheme: We present a preliminary result of Nf=2+1 QCD running coupling in\nSchroedinger functional scheme. We adopted Iwasaki gauge action and\nnon-perturbatively improved Wilson fermion action with clover term. We use\nseven renormalization scales to cover from low energy to high energy\nperturbative region and three lattice spacings to take the continuum limit at\neach scale.\n  A scaling behabior of the step scaling function is discussed together with\nits renoralization group flow in the continuum. We argue on introduction of the\nphysical scale through the Sommer scale r0.",
        "positive": "Complex-Temperature Singularities in the $d=2$ Ising Model. III.\n  Honeycomb Lattice: We study complex-temperature properties of the uniform and staggered\nsusceptibilities $\\chi$ and $\\chi^{(a)}$ of the Ising model on the honeycomb\nlattice. From an analysis of low-temperature series expansions, we find\nevidence that $\\chi$ and $\\chi^{(a)}$ both have divergent singularities at the\npoint $z=-1 \\equiv z_{\\ell}$ (where $z=e^{-2K}$), with exponents\n$\\gamma_{\\ell}'= \\gamma_{\\ell,a}'=5/2$. The critical amplitudes at this\nsingularity are calculated. Using exact results, we extract the behaviour of\nthe magnetisation $M$ and specific heat $C$ at complex-temperature\nsingularities. We find that, in addition to its zero at the physical critical\npoint, $M$ diverges at $z=-1$ with exponent $\\beta_{\\ell}=-1/4$, vanishes\ncontinuously at $z=\\pm i$ with exponent $\\beta_s=3/8$, and vanishes\ndiscontinuously elsewhere along the boundary of the complex-temperature\nferromagnetic phase. $C$ diverges at $z=-1$ with exponent $\\alpha_{\\ell}'=2$\nand at $v=\\pm i/\\sqrt{3}$ (where $v = \\tanh K$) with exponent $\\alpha_e=1$, and\ndiverges logarithmically at $z=\\pm i$. We find that the exponent relation\n$\\alpha'+2\\beta+\\gamma'=2$ is violated at $z=-1$; the right-hand side is 4\nrather than 2. The connections of these results with complex-temperature\nproperties of the Ising model on the triangular lattice are discussed."
    },
    {
        "anchor": "QCD topology with electromagnetic fields and the axion-photon coupling: The introduction of non-orthogonal electric and magnetic fields in the QCD\nvacuum enhances the weight of topological sectors with a nonzero topological\ncharge. For weak fields, there is a linear response for the expectation value\nof the topological charge. We study this linear response and relate it to the\nQCD correction to the axion-photon coupling. We also analyse the magnetic field\ndependence of the topological susceptibility for a range of temperatures around\n$T_c$. In this work we use lattice simulations with improved staggered quarks\nat physical masses, including background magnetic and (imaginary) electric\nfields.",
        "positive": "Probing the Aoki phase with N_f=2 Wilson fermions at finite temperature: In this letter we report on a numerical investigation of the Aoki phase in\nthe case of finite temperature which continues our former study at zero\ntemperature. We have performed simulations with Wilson fermions at $\\beta=4.6$\nusing lattices with temporal extension $N_{\\tau}=4$. In contrast to the zero\ntemperature case, the existence of an Aoki phase can be confirmed for a small\nrange in $\\kappa$ at $\\beta=4.6$, however, shifted slightly to lower $\\kappa$.\nDespite fine-tuning $\\kappa$ we could not separate the thermal transition line\nfrom the Aoki phase."
    },
    {
        "anchor": "Finite-volume energy shift of the three-nucleon ground state: A perturbative calculation of the three-nucleon ground-state energy shift in\na finite volume is carried out within the non-relativistic effective theory.\nThe energy shift is evaluated up to and including $\\mathcal{O}(L^{-6})$, where\n$L$ is the size of a cubic box. The convergence of the perturbative series at\nphysical values of the scattering lengths is studied numerically.",
        "positive": "Center Vortex vs. Abelian models of the QCD vacuum: We present evidence that the center vortex model of confinement is more\nconsistent with lattice results than other currently available models. In\nparticular we show that Abelian field distributions predicted by monopole\nplasma, caloron gas or dual superconductor models cannot reproduce the area-law\nfalloff of double winding Wilson loops in full $SU(2)$ and center vortex only\ngauge fields."
    },
    {
        "anchor": "Abelian chromomagnetic background field at finite temperature on the\n  lattice: The vacuum dynamics of SU(2) and SU(3) lattice gauge theories is studied by\nmeans of a gauge-invariant effective action defined using the lattice\nSchr\\\"odinger functional at finite temperature. In the case of the SU(3) gauge\ntheory numerical simulations are performed both at zero and finite temperature.\nThe vacuum is probed using an external constant Abelian chromomagnetic field.\nAt zero temperature, in agreement with our previous studies for the SU(2)\ntheory, the external field is totally screened in the continuum limit. At\nfinite temperature numerical data suggest that confinement is restored by\nincreasing the strength of the applied field.",
        "positive": "Renormalization and Mixing of the Gluino-Glue Operator on the Lattice: We study the mixing of the Gluino-Glue operator in ${\\cal N}$=1\nSupersymmetric Yang-Mills theory (SYM), both in dimensional regularization and\non the lattice. We calculate its renormalization, which is not only\nmultiplicative, due to the fact that this operator can mix with non-gauge\ninvariant operators of equal or, on the lattice, lower dimension. These\noperators carry the same quantum numbers under Lorentz transformations and\nglobal gauge transformations, and they have the same ghost number.\n  We compute the one-loop quantum correction for the relevant two-point and\nthree-point Green's functions of the Gluino-Glue operator. This allows us to\ndetermine renormalization factors of the operator in the\n$\\overline{\\textrm{MS}}$ scheme, as well as the mixing coefficients for the\nother operators. To this end our computations are performed using dimensional\nand lattice regularizations. We employ a standard discretization where gluinos\nare defined on lattice sites and gluons reside on the links of the lattice; the\ndiscretization is based on Wilson's formulation of non-supersymmetric gauge\ntheories with clover improvement. The number of colors, $N_c$, the gauge\nparameter, $\\beta$, and the clover coefficient, $c_{\\rm SW}$, are left as free\nparameters."
    },
    {
        "anchor": "Filtered topological structure of the QCD vacuum: Effects of dynamical\n  quarks: We systematically compare filtering methods used to extract topological\nstructures on SU(3) lattice configurations. We show that there is a strong\ncorrelation of the topological charge densities obtained by APE and Stout\nsmearing. To get rid of artifacts of these methods, we analyse structures that\nare also seen by Laplace filtering and indeed identify artifacts for strong\nsmearing. The topological charge density in this combined analysis is more\nfragmented in the presence of dynamical quarks. A power law exponent that\ncharacterises the distribution of filtered topological clusters turns out to be\nnot far off the values of an instanton gas model.",
        "positive": "Coulomb vs. physical string tension on the lattice: From continuum studies it is known that the Coulomb string tension $\\sigma_C$\ngives an upper bound for the physical (Wilson) string tension $\\sigma_W$ [D.\nZwanziger, Phys. Rev. Lett. 90, 102001 (2003)]. How does however such\nrelationship translate to the lattice? In this paper we give evidence that\nthere, while the two string tensions are related at zero temperature, they\ndecouple at finite temperature. More precisely, we show that on the lattice the\nCoulomb gauge confinement scenario is always tied to the spatial string\ntension, which is known to survive the deconfinement phase transition and to\ncause screening effects in the quark-gluon plasma. Our analysis is based on the\nidentification and elimination of center vortices which allows to control the\nphysical string tension and study its effect on the Coulomb gauge observables.\nWe also show how alternative definitions of the Coulomb potential may sense the\ndeconfinement transition; however a true static Coulomb gauge order parameter\nfor the phase transition is still elusive on the lattice."
    },
    {
        "anchor": "Charmonium correlators and spectral functions at finite temperature: We present an operational approach to address the in-medium behavior of\ncharmonium and analyze the reliability of maximum entropy method (MEM). We\nstudy the dependences of the ratio of correlators to the reconstructed one and\nthe free one on the resonance's width and the continuum's threshold.\nFurthermore, we discuss the issue of the default model dependence of the\nspectral function obtained from MEM.",
        "positive": "Polyakov loop and spin correlators on finite lattices A study beyond the\n  mass gap: We derive an analytic expression for point-to-point correlation functions of\nthe Polyakov loop based on the transfer matrix formalism. For the $2d$ Ising\nmodel we show that the results deduced from point-point spin correlators are\ncoinciding with those from zero momentum correlators. We investigate the\ncontributions from eigenvalues of the transfer matrix beyond the mass gap and\ndiscuss the limitations and possibilities of such an analysis. The finite size\nbehaviour of the obtained $2d$ Ising model matrix elements is examined. The\npoint-to-point correlator formula is then applied to Polyakov loop data in\nfinite temperature $SU(2)$ gauge theory. The leading matrix element shows all\nexpected scaling properties. Just above the critical point we find a Debye\nscreening mass $~\\mu_D/T\\approx4~$, independent of the volume."
    },
    {
        "anchor": "The $\u03c1$-meson light-cone distribution amplitudes from lattice QCD: We present the results of a lattice study of the normalization constants and\nsecond moments of the light-cone distribution amplitudes of longitudinally and\ntransversely polarized $\\rho$ mesons. The calculation is performed using two\nflavors of dynamical clover fermions at lattice spacings between\n$0.060\\,\\text{fm}$ and $0.081\\,\\text{fm}$, different lattice volumes up to\n$m_\\pi L = 6.7$ and pion masses down to $m_\\pi=150\\,\\text{MeV}$. Bare lattice\nresults are renormalized non-perturbatively using a variant of the RI'-MOM\nscheme and converted to the $\\overline{\\text{MS}}$ scheme. The necessary\nconversion coefficients, which are not available in the literature, are\ncalculated. The chiral extrapolation for the relevant decay constants is worked\nout in detail. We obtain for the ratio of the tensor and vector coupling\nconstants $f_\\rho^T/f_\\rho^{\\vphantom{T}} = 0.629(8)$ and the values of the\nsecond Gegenbauer moments $a_2^\\parallel = 0.132(27)$ and $a_2^\\perp =\n0.101(22)$ at the scale $\\mu = 2\\,\\text{GeV}$ for the longitudinally and\ntransversely polarized $\\rho$ mesons, respectively. The errors include the\nstatistical uncertainty and estimates of the systematics arising from\nrenormalization. Discretization errors cannot be estimated reliably and are not\nincluded. In this calculation the possibility of $\\rho\\to\\pi\\pi$ decay at the\nsmaller pion masses is not taken into account.",
        "positive": "Rho resonance parameters from lattice QCD: We perform a high-precision calculation of the phase shifts for $\\pi$-$\\pi$\nscattering in the I = 1, J = 1 channel in the elastic region using elongated\nlattices with two mass-degenerate quark favors ($N_f = 2$). We extract the\n$\\rho$ resonance parameters using a Breit-Wigner fit at two different quark\nmasses, corresponding to $m_{\\pi} = 226$MeV and $m_{\\pi} = 315$MeV, and perform\nan extrapolation to the physical point. The extrapolation is based on a\nunitarized chiral perturbation theory model that describes well the\nphase-shifts around the resonance for both quark masses. We find that the\nextrapolated value, $m_{\\rho} = 720(1)(15)$MeV, is significantly lower that the\nphysical rho mass and we argue that this shift could be due to the absence of\nthe strange quark in our calculation."
    },
    {
        "anchor": "Quantum Simulation of the N flavor Gross-Neveu Model: We discuss the use of quantum simulation to study an $N$ flavor theory of\ninteracting relativistic fermions in(1+1) dimensions on NISQ era machines. The\ncase of two flavors is particularly interesting as it can be mapped to the\nHubbard model. We derive the appropriate qubit Hamiltonians and associated\nquantum circuits. We compare classical simulation and DMRG/TEBD calculations\nwith the results of quantum simulation on various platforms for $N$=2 and 4. We\ndemonstrate that the four steps of the calculations of real-time scattering can\nactually be implemented using current NISQ devices.",
        "positive": "Real-time lattice gauge theory actions: unitarity, convergence, and path\n  integral contour deformations: The Wilson action for Euclidean lattice gauge theory defines a\npositive-definite transfer matrix that corresponds to a unitary lattice gauge\ntheory time-evolution operator if analytically continued to real time. Hoshina,\nFujii, and Kikukawa (HFK) recently pointed out that applying the Wilson action\ndiscretization to continuum real-time gauge theory does not lead to this, or\nany other, unitary theory and proposed an alternate real-time lattice gauge\ntheory action that does result in a unitary real-time transfer matrix. The\ncharacter expansion defining the HFK action is divergent, and in this work we\napply a path integral contour deformation to obtain a convergent representation\nfor U(1) HFK path integrals suitable for numerical Monte Carlo calculations. We\nalso introduce a class of real-time lattice gauge theory actions based on\nanalytic continuation of the Euclidean heat-kernel action. Similar divergent\nsums are involved in defining these actions, but for one action in this class\nthis divergence takes a particularly simple form, allowing construction of a\npath integral contour deformation that provides absolutely convergent\nrepresentations for U(1) and SU(N) real-time lattice gauge theory path\nintegrals. We perform proof-of-principle Monte Carlo calculations of real-time\nU(1) and SU(3) lattice gauge theory and verify that exact results for unitary\ntime evolution of static quark-antiquark pairs in (1 + 1)D are reproduced."
    },
    {
        "anchor": "Understanding nucleon structure using lattice simulations: This review focuses on the discussion of three key results of nucleon\nstructure calculations on the lattice. These three results are the quark\ncontribution to the nucleon spin, J_q, the nucleon-Delta transition form\nfactors, and the nucleon axial coupling, g_A. The importance for phenomenology\nand experiment is discussed and the requirements for future simulations are\npointed out.",
        "positive": "Chiral polarization scale of QCD vacuum and spontaneous chiral symmetry\n  breaking: It has recently been found that dynamics of pure glue QCD supports the low\nenergy band of Dirac modes with local chiral properties qualitatively different\nfrom that of a bulk: while bulk modes suppress chirality relative to\nstatistical independence between left and right, the band modes enhance it. The\nwidth of such chirally polarized zone - chiral polarization scale Lambda_ch -\nhas been shown to be finite in the continuum limit at fixed physical volume.\nHere we present evidence that Lambda_ch remains non-zero also in the infinite\nvolume, and is therefore a dynamical scale in the theory. Our experiments in\nN_f=2+1 QCD support the proposition that the same holds in the massless limit,\nconnecting Lambda_ch to spontaneous chiral symmetry breaking. In addition, our\nresults suggest that thermal agitation in quenched QCD destroys both chiral\npolarization and condensation of Dirac modes at the same temperature T_ch >\nT_c."
    },
    {
        "anchor": "Perturbative matching of lattice and continuum heavy-light currents with\n  NRQCD heavy quarks: The temporal and spatial components of the heavy-light vector current and the\nspatial components of the axial current are expressed in terms of\nlattice-regulated operators suitable for simulations of B and D mesons. The\ncurrents are constructed by matching the appropriate scattering amplitudes in\ncontinuum QCD and a lattice model to one-loop order in perturbation theory. In\nthe lattice theory, the heavy quarks are treated using the nonrelativistic\n(NRQCD) formulation and the light quarks are described by the tadpole-improved\nclover action. The light quarks are treated as massless. Our currents include\nrelativistic and discretization corrections through O(alpha_s/M, a alpha_s),\nwhere M is the heavy-quark mass, a is the lattice spacing, and alpha_s is the\nQCD coupling. As in our previous construction of the temporal component of the\nheavy-light axial current, mixing between several lattice operators is\nencountered at one-loop order, and O(a alpha_s) dimension-four improvement\nterms are identified.",
        "positive": "Studying $\u03ba$ meson with a MILC fine lattice: Using the lattice simulations in the Asqtad-improved staggered fermion\nformulation we compute the point-to-point $\\kappa$ correlators, which are\nanalyzed by the rooted staggered chiral perturbation theory (rS$\\chi$PT). After\nchiral extrapolation, we secure the physical $\\kappa$ mass with $835\\pm93$ MeV,\nwhich is in agreement with the BES experimental results. The computations are\nperformed using a MILC 2+1 flavor fine gauge configuration at a lattice spacing\nof $a \\approx 0.09$ fm."
    },
    {
        "anchor": "Simulating rare kaon decays $K^{+}\\to\u03c0^{+}\\ell^{+}\\ell^{-}$ using\n  domain wall lattice QCD with physical light quark masses: We report the first calculation using physical light-quark masses of the\nelectromagnetic form factor $V(z)$ describing the long-distance contributions\nto the $K^+\\to\\pi^+\\ell^+\\ell^-$ decay amplitude. The calculation is performed\non a 2+1 flavor domain wall fermion ensemble with inverse lattice spacing\n$a^{-1}=1.730(4)$GeV. We implement a Glashow-Iliopoulos-Maiani cancellation by\nextrapolating to the physical charm-quark mass from three below-charm masses.\nWe obtain $V(z=0.013(2))=-0.87(4.44)$, achieving a bound for the value. The\nlarge statistical error arises from stochastically estimated quark loops.",
        "positive": "Supersymmetry non-renormalization theorem from a computer and the\n  AdS/CFT correspondence: We perform Monte Carlo calculation of correlation functions in 4d N=4 super\nYang-Mills theory on R*S^3 in the planar limit. In order to circumvent the\nwell-known problem of lattice SUSY, we adopt the idea of a novel large-N\nreduction, which reduces the calculation to that of corresponding correlation\nfunctions in the plane-wave matrix model or the BMN matrix model. This model is\na 1d gauge theory with 16 supersymmetries, which can be simulated in a manner\nsimilar to the recent studies of the D0-brane system. We study two-point and\nthree-point functions of chiral primary operators at various coupling constant,\nand find that they agree with the free theory results up to overall constant\nfactors. The ratio of the overall factors for two-point and three-point\nfunctions agrees with the prediction of the AdS/CFT correspondence."
    },
    {
        "anchor": "Semileptonic Decays of D and B Mesons: We report results of our ongoing investigation concerning semileptonic decays\nof heavy pseudoscalar mesons into pseudoscalar and vector mesons. Particular\nattention is paid to uncertainties in the $q^2$ and the heavy quark mass\ndependence of formfactors. Moreover we present a non-perturbative test to the\nLMK current renormalization scheme for vector current transition matrix\nelements and find remarkable agreement.",
        "positive": "Compact fields and mass generation: It is shown that the free propagator of an angular, i.e. compact, field with\nzero lagrangian mass acquires a nonzero propagator mass $\\omega$ (`kinematical'\nmass generation). To demonstrate this effect the free propagator of the\ngoldstone boson in an O(2) model with spontaneous symmetry breaking is\ncalculated. It is shown that this propagator is massive, the mass $\\omega$\nbeing a function of the scalar `condensate' ${\\bar\\phi}$."
    },
    {
        "anchor": "Cutoff-effects in the spectrum of dynamical Wilson fermions: We investigate the low-lying eigenvalues of the improved Wilson-Dirac\noperator in the Schroedinger functional with two dynamical quark flavors. At a\nlattice spacing of approximately 0.1 fm we find more very small eigenvalues\nthan in the quenched case. These cause problems with HMC-type algorithms and in\nthe evaluation of fermionic correlation functions. Through a simulation at a\nfiner lattice spacing we are able to establish their nature as cutoff-effects",
        "positive": "Finite Volume and Partially Quenched QCD-like Effective Field Theories: We present a calculation of the meson masses, decay constants and\nquark-antiquark vacuum expectation value for the three generic QCD-like chiral\nsymmetry breaking patterns $SU(N_F)\\times SU(N_F)\\to SU(N_F)_V$, $SU(N_F)\\to\nSO(N_F)$ and $SU(2N_F)\\to Sp(2 N_F)$ in the effective field theory for these\ncases. We extend the previous two-loop work to include effects of partial\nquenching and finite volume.\n  The calculation has been performed using the quark flow technique. We\nreproduce the known infinite volume results in the unquenched case. The\nanalytical results can be found in the supplementary material.\n  Some examples of numerical results are given. The numerical programs for all\ncases are included in version 0.54 of the CHIRON package.\n  The purpose of this work is the use in lattice extrapolations to zero mass\nfor QCD-like and strongly interacting Higgs sector lattice calculations."
    },
    {
        "anchor": "Phase structure of SU(3) gauge theory with two flavors of\n  symmetric-representation fermions: We have performed numerical simulations of SU(3) gauge theory coupled to Nf=2\nflavors of symmetric representation fermions. The fermions are discretized with\nthe tadpole-improved clover action. Our simulations are done on lattices of\nlength L=6, 8, and 12. In all simulation volumes we observe a crossover from a\nstrongly coupled confined phase to a weak coupling deconfined phase.\nDegeneracies in screening masses, plus the behavior of the pseudoscalar decay\nconstant, indicate that the deconfined phase is also a phase in which chiral\nsymmetry is restored. The movement of the confinement transition as the volume\nis changed is consistent with avoidance of the basin of attraction of an\ninfrared fixed point of the massless theory.",
        "positive": "Small flow-time representation of fermion bilinear operators: Fermion bilinear operators of mass dimension~$3$, such as the axial-vector\nand vector currents, the pseudo-scalar and scalar densities, whose\nnormalizations are fixed by Ward--Takahashi (WT) relations, are related to\nsmall flow-time behavior of composite operators of fermion fields evolved by\nL\\\"uscher's flow equation. The representations can be useful in lattice\nnumerical simulations, as recently demonstrated by the WHOT QCD collaboration\nfor the chiral condensation of the $N_f=2+1$ quantum chromodynamics (QCD) at\nfinite temperature."
    },
    {
        "anchor": "Computation of the improvement coefficient $c_{\\rm sw}$ to 1-loop with\n  improved gluon actions: The coefficient $c_{\\rm sw}$ appearing in the Sheikholeslami-Wohlert improved\naction is computed to one loop perturbation theory for improved gluon actions\nincluding six-link loops. The O($a$) improvement coefficients for the dimension\nthree isovector composite operators bilinear in the quark fields are also\ncomputed to one loop order of perturbation theory with degenerate non-vanishing\nquark masses.",
        "positive": "Investigations of supersymmetric Yang--Mills theories: We present new results from ongoing lattice investigations of supersymmetric\nYang--Mills (SYM) theories in three and four space-time dimensions. First\nconsidering the maximally supersymmetric 3d theory with $Q = 16$ supercharges,\nwe check that the fermion pfaffian is approximately real and positive,\nvalidating phase-quenched RHMC calculations. We then initiate lattice studies\nof running couplings and non-perturbative $\\beta$ functions for $Q = 16$ SYM in\nboth 3d and 4d, using a simple scheme based on Creutz ratios. Finally, we\nconsider 3d SYM with $Q = 8$ supercharges, developing new software as a first\nstep towards supersymmetric QCD."
    },
    {
        "anchor": "A lattice study of the masses of singlet 0++ mesons: We compute the masses of the flavour singlet 0++ mesons using (n_f=2)\nunquenched lattice QCD with the Iwasaki and Wilson gauge actions. Both\nfermionic and glueball interpolating operators are used to create the states.\nThe mass of the lightest 0++ meson is suppressed relative to the mass of the\n0++ glueball in quenched QCD at an equivalent lattice spacing. We discuss two\npossible physical reasons for this.",
        "positive": "QED interaction effects on heavy meson masses from lattice QCD+QED: Hadron masses are subject to few MeV corrections arising from QED\ninteractions, almost entirely arising from the electric charge of the valence\nquarks. The QED effects include both self-energy contributions and interactions\nbetween the valence quarks/anti-quarks. By combining results from different\nsigns of the valence quark electric charge we are able to isolate the\ninteraction term which is dominated by the Coulomb piece, $\\langle\n\\alpha_{\\mathrm{QED}}e_{q_1}e_{\\overline{q}_2}/r \\rangle$, in the\nnonrelativistic limit. We study this for $D_s$, $\\eta_c$ and $J/\\psi$ mesons,\nworking in lattice QCD plus quenched QED. We use gluon field configurations\nthat include up, down, strange and charm quarks in the sea at multiple values\nof the lattice spacing. Our results, including also values for mesons with\nquarks heavier than charm, can be used to improve phenomenological models for\nthe QED contributions. The QED interaction term carries information about meson\nstructure; we derive effective sizes $\\langle 1/r_{\\mathrm{eff}} \\rangle^{-1}$\nfor $\\eta_c$, $J/\\psi$ and $D_s$ of 0.206(8) fm, 0.321(14) fm and 0.307(31) fm\nrespectively."
    },
    {
        "anchor": "In quest of the Yang-Mills vacuum wavefunctional: A simple recursion procedure was devised to generate lattice configurations\nwith probability distributions given by simple approximate Yang-Mills vacuum\nwavefunctionals. A few quantities determined in ensembles of these\nconfigurations are compared to those computed in configurations generated in\nstandard Monte Carlo simulations of the three-dimensional Yang-Mills theory.",
        "positive": "Intersections of thick Center Vortices, Dirac Eigenmodes and Fractional\n  Topological Charge in SU(2) Lattice Gauge Theory: Intersections of thick, plane SU(2) center vortices are characterized by the\ntopological charge |Q|=1/2. We compare such intersections with the distribution\nof zeromodes of the Dirac operator in the fundamental and adjoint\nrepresentation using both the overlap and asqtad staggered fermion formulations\nin SU(2) lattice gauge theory. We analyze configurations with four\nintersections and find that the probability density distribution of fundamental\nzeromodes in the intersection plane differs significantly from the one obtained\nanalytically in [Phys.\\ Rev.\\ D 66, 85004 (2002)]. The Dirac eigenmodes are\nclearly sensitive to the traces of the Polyakov (Wilson) lines and do not\nexactly locate topological charge contributions. Although, the adjoint Dirac\noperator is able to produce zeromodes for configurations with topological\ncharge |Q|=1/2, they do not locate single vortex intersections, as we prove by\nforming arbitrary linear combinations of these zeromodes - their scalar density\npeaks at least at two intersection points. With pairs of thin and thick\nvortices we realize a situation similar to configurations with topological\ncharge |Q|=1/2. For such configurations the zeromodes do not localize in the\nregions of fractional topological charge contribution but spread over the whole\nlattice, avoiding regions of negative traces of Polyakov lines."
    },
    {
        "anchor": "Non-perturbative renormalization of the chromo-magnetic operator in\n  Heavy Quark Effective Theory and the B* - B mass splitting: We carry out the non-perturbative renormalization of the chromo-magnetic\noperator in Heavy Quark Effective Theory. At order 1/m of the expansion, the\noperator is responsible for the mass splitting between the pseudoscalar and\nvector B mesons. We obtain its two-loop anomalous dimension in a Schr\"odinger\nfunctional scheme by successive one-loop conversions to the lattice MS scheme\nand the MS-bar scheme. We then compute the scale evolution of the operator\nnon-perturbatively in the N_f=0 theory between $\\mu \\approx 0.3$ GeV and $\\mu\n\\approx 100$ GeV, where contact is made with perturbation theory. The overall\nrenormalization factor that converts the bare lattice operator to its\nrenormalization group invariant form is given for the Wilson gauge action and\ntwo standard discretizations of the heavy-quark action. As an application, we\nfind that this factor brings the previous quenched predictions of the B* - B\nmass splitting closer to the experimental value than found with a perturbative\nrenormalization. The same renormalization factor is applicable to the\nspin-dependent potentials of Eichten and Feinberg.",
        "positive": "Quark disconnected diagrams in chiral perturbation theory - the scalar\n  form factor: Expressions for the Wick contractions contributing to the scalar pion\nform-factor were computed model-independently in chiral perturbation theory at\nnext-to-leading order. The results reveal correlations amongst the different\ncontractions in terms of low-energy constants and allow for extrapolating\nlattice data for individual Wick contractions. The quark disconnected\ncontribution to the real part of the form factor turns out to be suppressed\nwith respect to the quark connected one. The corresponding contribution to the\nscalar radius has the same size as the connected contribution and can therefore\nnot be neglected."
    },
    {
        "anchor": "Self-consistent Calculation of Real Space Renormalization Group Flows\n  and Effective Potentials: We show how to compute real space renormalization group flows in lattice\nfield theory by a self-consistent method. In each step, the integration over\nthe fluctuation field (high frequency components of the field) is performed by\na saddle point method. The saddle point depends on the block-spin. Higher\npowers of derivatives of the field are neglected in the actions, but no\npolynomial approximation in the field is made. The flow preserves a simple\nparameterization of the action. In this paper we treat scalar field theories as\nan example.",
        "positive": "Multimagnetical Simulations: We modified the recently proposed multicanonical MC algorithm for the case of\na magnetic field driven order--order phase transition. We test this {\\it\nmultimagnetic} Monte Carlo algorithm for the D=2 Ising model at $\\beta=0.5$ and\nsimulate square lattices up to size $100 \\times 100$. On these lattices with\nperiodic boundary conditions it is possible to enhance the appearance of\norder-order interfaces during the simulation by many orders of magnitude as\ncompared to the standard Monte Carlo simulation."
    },
    {
        "anchor": "Contribution of the QCD $\u0398$-term to nucleon electric dipole moment: We present a calculation of the contribution of the $\\Theta$-term to the\nneutron and proton electric dipole moments using seven 2+1+1-flavor HISQ\nensembles. We also estimate the topological susceptibility for the 2+1+1 theory\nto be $\\chi_Q = (66(9)(4) \\rm MeV)^4$ in the continuum limit at $M_\\pi = 135$\nMeV. The calculation of the nucleon three-point function is done using\nWilson-clover valence quarks. The CP-violating form factor $F_3$ is calculated\nby expanding in small $\\Theta$. We show that lattice artifacts introduce a term\nproportional to $a$ that does not vanish in the chiral limit, and we include\nthis in our chiral-continuum fits. A chiral perturbation theory analysis shows\nthat the $N(0) \\pi(0)$ state should provide the leading excited state\ncontribution, and we study the effect of such a state. Detailed analysis of the\ncontributions to the neutron and proton electric dipole moment using two\nstrategies for removing excited state contamination are presented. Using the\nexcited state spectrum from fits to the two-point function, we find\n$d_n^\\Theta$ is small, $|d_n^\\Theta| \\lesssim 0.01 \\overline \\Theta e$ fm,\nwhereas for the proton we get $|d_p^\\Theta| \\sim 0.02 \\overline \\Theta e$ fm.\nOn the other hand, if the dominant excited-state contribution is from the $N\n\\pi$ state, then $|d_n^\\Theta|$ could be as large as $0.05 \\overline \\Theta e$\nfm and $|d_p^\\Theta| \\sim 0.07 \\overline \\Theta e$ fm. Our overall conclusion\nis that present lattice QCD calculations do not provide a reliable estimate of\nthe contribution of the $\\Theta$-term to the nucleon electric dipole moments,\nand a factor of ten higher statistics data are needed to get better control\nover the systematics and possibly a $3\\sigma$ result.",
        "positive": "Charmonium properties in the quark-gluon plasma: We present results for charmonium correlators and spectral functions in\n2-flavour CD on anisotropic lattices. Our results indicate that the S-waves\n(J/psi and eta_c) survive up to temperatures close to 2T_c, while the P-waves\n(chi_c0 and chi_c1) melt away below 1.2T_c."
    },
    {
        "anchor": "Chiral Corrections to Hyperon Axial Form Factors: We study the complete set of flavor changing hyperon axial current matrix\nelements at small momentum transfer. Using partially quenched heavy baryon\nchiral perturbation theory, we derive the chiral and momentum behavior of the\naxial and induced pseudoscalar form factors. The meson pole contributions to\nthe latter posses a striking signal for chiral physics. We argue that the study\nof hyperon axial matrix elements enables a systematic lattice investigation of\nthe efficacy of three flavor chiral expansions in the baryon sector. This can\nbe achieved by considering chiral corrections to SU(3) symmetry predictions,\nand their partially quenched generalizations. In particular, despite the\npresence of eight unknown low-energy constants, we are able to make\nnext-to-leading order symmetry breaking predictions for two linear combinations\nof axial charges.",
        "positive": "More about excited bottomonium radiative decays: Radiative decays of bottomonium are revisited, focusing on contributions from\nhigher-order relativistic effects. The leading relativistic correction to the\nmagnetic spin-flip operator at the photon vertex is found to be particularly\nimportant. The combination of O(v^6) effects in the nonrelativistic QCD action\nand in the transition operator moves previous lattice results for excited\nUpsilon decays into agreement with experiment."
    },
    {
        "anchor": "Most Strange Dibaryon from Lattice QCD: The $\\Omega\\Omega$ system in the $^1S_0$ channel (the most strange dibaryon)\nis studied on the basis of the (2+1)-flavor lattice QCD simulations with a\nlarge volume (8.1 fm)$^3$ and nearly physical pion mass $m_{\\pi}\\simeq 146$ MeV\nat a lattice spacing $a\\simeq 0.0846$ fm. We show that lattice QCD data\nanalysis by the HAL QCD method leads to the scattering length $a_0 = 4.6\n(6)(^{+1.2}_{-0.5}) {\\rm fm}$, the effective range $r_{\\rm eff} = 1.27\n(3)(^{+0.06}_{-0.03}) {\\rm fm}$ and the binding energy $B_{\\Omega \\Omega} = 1.6\n(6) (^{+0.7}_{-0.6}) {\\rm MeV}$. These results indicate that the $\\Omega\\Omega$\nsystem has an overall attraction and is located near the unitary regime. Such a\nsystem can be best searched experimentally by the pair-momentum correlation in\nrelativistic heavy-ion collisions.",
        "positive": "Electromagnetic form factor of the pion from twisted-mass lattice QCD at\n  Nf=2: We present a lattice calculation of the electromagnetic form factor of the\npion obtained using the tree-level Symanzik improved gauge action with two\nflavors of dynamical twisted Wilson quarks. The simulated pion masses range\napproximately from 260 to 580 MeV and the lattice box sizes are chosen in order\nto guarantee that M L > 4. Accurate results for the form factor are obtained\nusing all-to-all quark propagators evaluated by a stochastic procedure. The\nmomentum dependence of the pion form factor is investigated up to values of the\nsquared four-momentum transfer Q**2 ~ 0.8 GeV**2 and, thanks to the use of\ntwisted boundary conditions, down to Q**2 ~ 0.05 GeV**2. Volume and\ndiscretization effects on the form factor appear to be within the statistical\nerrors. Our results for the pion mass, decay constant and form factor are\nanalyzed using (continuum) Chiral Perturbation Theory at\nnext-to-next-to-leading order. The extrapolated value of the pion charge radius\nis <r**2>{phys} = 0.456 +/- 0.030(stat.) +/- 0.024(syst.) in nice agreement\nwith the experimental result. The extrapolated values of the pion form factor\nagree very well with the experimental data up to Q**2 ~ 0.8 GeV**2 within\nuncertainties which become competitive with the experimental errors for Q**2 >\n0.3 GeV**2. The relevant low-energy constants appearing in the chiral expansion\nof the pion form factor are extracted from our lattice data, which come\nessentially from a single lattice spacing, adding the experimental value of the\npion scalar radius in the fitting procedure. Our findings are in nice agreement\nwith the available results of ChPT analyses of pion-pion scattering data as\nwell as with other analyses of our collaboration."
    },
    {
        "anchor": "Subvolume method for SU(2) Yang-Mills theory at finite temperature:\n  topological charge distributions: We apply the previously-developed sub-volume method to study the\n$\\theta$-dependence of the four-dimensional SU(2) Yang-Mills theory. We\ncalculate the first two coefficients, the topological susceptibility $\\chi$ and\nthe fourth cumulant $b_2$, in the $\\theta$-expansion of the free energy density\naround the critical temperature for the confinement-deconfinement transition.\nLattice calculations are performed with three different spatial sizes\n$24^3,32^3,48^3$ to monitor finite size effects, while the temporal size is\nfixed to be $8$. The sub-volume method allows us to determine the values of\n$b_2$ much more accurately than the standard full-volume method, and we have\nsuccessfully measured the temperature dependence of $b_2$ around the critical\ntemperature. Our numerical results suggest that the $\\theta$-dependence of the\nfree energy density changes approximately from $4\\chi(1-\\cos(\\theta/2))$ to\n$\\chi(1-\\cos\\theta)$ near $\\theta=0$ as the temperature increases.",
        "positive": "A Cluster Method for the Ashkin--Teller Model: A cluster Monte Carlo algorithm for the Ashkin-Teller (AT) model is\nconstructed according to the guidelines of a general scheme for such\nalgorithms. Its dynamical behaviour is tested for the square lattice AT model.\nWe perform simulations on the line of critical points along which the exponents\nvary continuously, and find that critical slowing down is significantly\nreduced. We find continuous variation of the dynamical exponent $z$ along the\nline, following the variation of the ratio $\\alpha/\\nu$, in a manner which\nsatisfies the Li-Sokal bound $z_{cluster}\\geq\\alpha/\\nu$, that was so far\nproved only for Potts models."
    },
    {
        "anchor": "Lattice QCD at non-zero baryon number: We discuss the quenched limit of lattice QCD at non-zero baryon number\ndensity. We find evidence for a mixed phase that becomes broader with\nincreasing baryon number. Although the action is explicitly Z(3) symmetric the\nPolyakov loop expectation value becomes non-zero already in the low temperature\nphase. It indicates that the heavy quark potential stays finite at large\ndistances, i.e. the string between static quarks breaks at non-zero baryon\nnumber density already in the hadronic phase. This behaviour is validated by\ncalculating the heavy quark potential using Polyakov loop correlations.",
        "positive": "Average up/down, strange and charm quark masses with Nf=2 twisted mass\n  lattice QCD: We present a high precision lattice calculation of the average up/down,\nstrange and charm quark masses performed with Nf=2 twisted mass Wilson\nfermions. The analysis includes data at four values of the lattice spacing and\npion masses as low as ~270 MeV, allowing for accurate continuum limit and\nchiral extrapolation. The strange and charm masses are extracted by using\nseveral methods, based on different observables: the kaon and the eta_s meson\nfor the strange quark and the D, D_s and eta_c mesons for the charm. The quark\nmass renormalization is carried out non-perturbatively using the RI-MOM method.\nThe results for the quark masses in the MSbar scheme read: m_ud(2 GeV)= 3.6(2)\nMeV, m_s(2 GeV)=95(6) MeV and m_c(m_c)=1.28(4) GeV. We also obtain the ratios\nm_s/m_ud=27.3(9) and m_c/m_s=12.0(3)."
    },
    {
        "anchor": "Twisted mass QCD for the pion electromagnetic form factor: The pion form factor is computed using quenched twisted mass QCD and the\nGMRES-DR matrix inverter. The momentum averaging procedure of Frezzotti and\nRossi is used to remove leading lattice spacing artifacts, and numerical\nresults for the form factor show the expected improvement with respect to the\nstandard Wilson action. Although some matrix inverters are known to fail when\napplied to twisted mass QCD, GMRES-DR is found to be a viable and powerful\noption. Results obtained for the pion form factor are consistent with the\npublished results from other O(a) improved actions and are also consistent with\nthe available experimental data.",
        "positive": "Updated evaluation of $\\varepsilon_K$ in the Standard Model with lattice\n  QCD inputs: We report a strong tension in $\\varepsilon_K$ at the $4\\sigma$ level between\nthe experimental value and the theoretical value calculated directly from the\nstandard model using lattice QCD inputs such as $\\hat{B}_K$, $|V_{cb}|$,\n$|V_{us}|$, $\\xi_0$, $\\xi_2$, $\\xi_\\text{LD}$, $F_K$, and $m_c$. The standard\nmodel with lattice QCD inputs describes only 70% of the experimental value of\n$\\varepsilon_K$, and does not explain its remaining 30%. We also find that this\ntension disappears when we use the inclusive value of $|V_{cb}|$ (results of\nthe heavy quark expansion based on QCD sum rules) to determine $\\varepsilon_K$.\nThis tension is highly correlated with the present discrepancy between the\nexclusive and inclusive values of $|V_{cb}|$. In order to resolve, in part, the\nissue with $|V_{cb}|$, it would be highly desirable to have a comprehensive\nre-analysis over the entire set of experimental data on the $\\bar{B} \\to D^*\n\\ell \\bar{\\nu}$ decays using an alternative parametrization of the form\nfactors, such as the BGL parametrization, and a comparison with results of the\nCLN method."
    },
    {
        "anchor": "The aliasing problem in lattice field theory: The intrinsically nonlinear nature of quantum field theory provides a\nfundamental complication for lattice calculations, when the physical\nimplications of the subtleties of Fourier theory are taken into account. Even\nthough the fundamental fields are constrained to the first Brillouin zone,\nFourier theory tells us that the high-momentum components of products of these\nfields \"bleed into\" neighbouring Brillouin zones, where they \"alias\" (or\n\"masquerade\") as low-momentum contributions, violating the conservation of\nenergy and momentum, and fundamentally distorting calculations. In this paper I\noffer a general strategy for eliminating the artefacts of aliasing in practical\ncalculations.",
        "positive": "Unpolarized and helicity generalized parton distributions of the proton\n  within lattice QCD: We present the first calculation of the $x$-dependence of the proton\ngeneralized parton distributions (GPDs) within lattice QCD. Results are\nobtained for the isovector unpolarized and helicity GPDs. We compute the\nappropriate matrix elements of fast-moving protons coupled to non-local\noperators containing a Wilson line. We present results for proton momenta\n$0.83,\\,1.25,\\,1.67$ GeV, and momentum transfer squared $0.69,\\,1.38$ GeV$^2$.\nThese combinations include cases with zero and nonzero skewness. The\ncalculation is performed using one ensemble of two degenerate mass light, a\nstrange and a charm quark of maximally twisted mass fermions with a clover\nterm. The lattice results are matched to the light-cone GPDs using one-loop\nperturbation theory within the framework of large momentum effective theory.\nThe final GPDs are given in the $\\overline{\\rm MS}$ scheme at a scale of 2 GeV."
    },
    {
        "anchor": "Can baryogenesis occur on the lattice?: We examine the question of how baryogenesis can occur in lattice models of\nthe Standard Model where there is a global $U(1)$ symmetry which is accompanied\nby an exactly conserved fermion number. We demonstrate that fermion creation\nand annihilation can occur in these models {\\em despite} this exact fermion\nnumber conservation, by explicitly computing the spectral flow of the\nhamiltonian in the two dimensional U(1) axial model with Wilson fermions. For\ncomparison we also study the closely related Schwinger model where a similar\nmechanism gives rise to anomalous particle creation and annihilation.",
        "positive": "On the condition for correct convergence in the complex Langevin method: The complex Langevin method (CLM) provides a promising way to perform the\npath integral with a complex action using a stochastic equation for\ncomplexified dynamical variables. It is known, however, that the method gives\nwrong results in some cases, while it works, for instance, in finite density\nQCD in the deconfinement phase or in the heavy dense limit. Here we revisit the\nargument for justification of the CLM and point out a subtlety in using the\ntime-evolved observables, which play a crucial role in the argument. This\nsubtlety requires that the probability distribution of the drift term should\nfall off exponentially or faster at large magnitude. We demonstrate our claim\nin some examples such as chiral Random Matrix Theory and show that our\ncriterion is indeed useful in judging whether the results obtained by the CLM\nare trustable or not."
    },
    {
        "anchor": "Delta I=1/2 rule from staggered fermions: We present our latest results for the Delta I=1/2 rule, obtained on quenched\nensembles with beta=6.0 and 6.2, and a set of N_f=2 configurations with\nbeta=5.7. The statistical noise is quite under control. We observe an\nenhancement of the Delta I=1/2 amplitude consistent with experiment, although\nthe systematic errors are still large. We also present a non-perturbative\ndetermination of Z_P, Z_S and the strange quark mass. We briefly discuss our\nprogress in calculating epsilon-prime.",
        "positive": "q \\bar q-potential: We show how to define and compute in a non-perturbative way the potential\nbetween q and \\bar q colour sources in the singlet and octet (adjoint)\nrepresentation of the colour group."
    },
    {
        "anchor": "Thermodynamic potentials from shifted boundary conditions: the\n  scalar-field theory case: In a thermal field theory, the cumulants of the momentum distribution can be\nextracted from the dependence of the Euclidean path integral on a shift in the\nfields built into the temporal boundary condition. When combined with the Ward\nidentities associated with the invariance of the theory under the Poincare'\ngroup, thermodynamic potentials such as the entropy or the pressure can be\ndirectly inferred from the response of the system to the shift. Crucially the\nargument holds, up to harmless finite-size and discretization effects, even if\ntranslational and rotational invariance are broken to a discrete subgroup of\nfinite shifts and rotations such as in a lattice box. The formulas are thus\napplicable at finite lattice spacing and volume provided the derivatives are\nreplaced by their discrete counterpart, and no additive or multiplicative\nultraviolet-divergent renormalizations are needed to take the continuum limit.\nIn this paper we present a complete derivation of the relevant formulas in the\nscalar field theory, where several technical complications are avoided with\nrespect to gauge theories. As a by-product we obtain a recursion relation among\nthe cumulants of the momentum distribution, and formulae for finite-volume\ncorrections to several well-known thermodynamic identities.",
        "positive": "Notes on (twisted) lattice supersymmetry: We describe a new approach to the problem of putting supersymmetric theories\non the lattice. The basic idea is to discretize a {\\it twisted} formulation of\nthe supersymmetric theory. For certain theories with extended supersymmetry\nthese twisted formulations contain only integer spin fields. The twisting\nexposes a scalar nilpotent supercharge which generates an exact lattice\nsymmetry. We gives examples from quantum mechanics, sigma models and Yang-Mills\ntheories."
    },
    {
        "anchor": "Phase Structure of Z(3)-Polyakov-Loop Models: We study effective lattice actions describing the Polyakov loop dynamics\noriginating from finite-temperature Yang-Mills theory. Starting with a\nstrong-coupling expansion the effective action is obtained as a series of\nZ(3)-invariant operators involving higher and higher powers of the Polyakov\nloop, each with its own coupling. Truncating to a subclass with two couplings\nwe perform a detailed analysis of the statistical mechanics involved. To this\nend we employ a modified mean field approximation and Monte Carlo simulations\nbased on a novel cluster algorithm. We find excellent agreement of both\napproaches concerning the phase structure of the theories. The phase diagram\nexhibits both first and second order transitions between symmetric,\nferromagnetic and anti-ferromagnetic phases with phase boundaries merging at\nthree tricritical points. The critical exponents nu and gamma at the continuous\ntransition between symmetric and anti-ferromagnetic phases are the same as for\nthe 3-state Potts model.",
        "positive": "Lattice String Breaking and Heavy Meson Decays: We show how string breaking on the lattice, treated as a mixing effect, can\nbe related to decay rates for heavy quark systems. We use this to make a\npreliminary calculation of the energy split at maximum mixing for static quarks\nin QCD from the decay rate for $\\Upsilon(4S)\\to B{\\bar B}$. We extend the\ncalculation to achieve rough estimates for the contributions of channels\ninvolving $B, B^*, B_s and B_s^*$ mesons to the width of the $\\Upsilon(5S)$."
    },
    {
        "anchor": "Spectroscopy of SU(4) lattice gauge theory with fermions in the two\n  index anti-symmetric representation: We present a study of spectroscopy of SU(4) lattice gauge theory coupled to\ntwo flavors of Dirac fermions in the anti-symmetric two index representation.\nThe fermion representation is real, and the pattern of chiral symmetry breaking\nis SU(2Nf) -> SO(2Nf) with Nf flavors of Dirac fermions. It is an interesting\ngeneralization of QCD, for several reasons: it allows direct exploration of an\nalternate large Nc expansion, it can be simulated at non-zero chemical\npotential with no sign problem, and several UV completions of composite Higgs\nsystems are built on it. We present preliminary results on the baryon and meson\nspectra of the theory and compare them with SU(3) results and with expectations\nfor large Nc scaling.",
        "positive": "Eigenvalue-flipping Algorithm for Matrix Monte Carlo: Many physical systems can be described in terms of matrix models that we\noften cannot solve analytically. Fortunately, they can be studied numerically\nin a straightforward way. Many commonly used algorithms follow the Monte Carlo\nmethod, which is efficient for small matrix sizes but cannot guarantee\nergodicity when working with large ones. In this paper, we propose an\nimprovement of the algorithm that, for a large class of matrix models, allows\nto tunnel between various vacua in a proficient way, where sign change of\neigenvalues is proposed externally. We test the method on two models: the pure\npotential matrix model and the scalar field theory on the fuzzy sphere."
    },
    {
        "anchor": "Excited-State Hadron Masses from Lattice QCD: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Large sets of spatially-extended hadron operators are used.\nThe need for multi-hadron operators in addition to single-hadron operators is\nemphasized, necessitating the use of a new stochastic method of treating the\nlow-lying modes of quark propagation which exploits Laplacian Heaviside\nquark-field smearing. A new glueball operator is tested, and computing the\nmixing of this glueball operator with a quark-antiquark operator and multiple\ntwo-pion operators is shown to be feasible.",
        "positive": "Microscopic Origin of \\boldmath{$U_A(1)$} Symmetry Violation in the High\n  Temperature Phase of QCD: We investigate the low-lying eigenmodes of the Dirac matrix with the aim to\ngain more insight into the temperature dependence of the anomalous $U_A(1)$\nsymmetry. We use the overlap operator to probe dynamical QCD configurations\ngenerated with (2+1)-flavors of highly improved staggered quarks. We find no\nevidence of a gap opening up in the infrared region of the eigenvalue spectrum\neven at $1.5\\,T_c$, $T_c$ being the chiral crossover temperature. Instead, we\nobserve an accumulation of near-zero eigenmodes. We argue that these near-zero\neigenmodes are primarily responsible for the anomalous breaking of the axial\nsymmetry still being effective. At $1.5\\,T_c$, these near-zero eigenmodes\nremain localized and their distribution is consistent with the dilute instanton\ngas picture. At this temperature, the average size of the instantons is\n$0.223(8)\\,\\text{fm}$ and their density is $0.147(7)\\,\\text{fm}^{-4}$."
    },
    {
        "anchor": "Analysis of Ward identities in supersymmetric Yang-Mills theory: In numerical investigations of supersymmetric Yang-Mills theory on a lattice,\nthe supersymmetric Ward identities are valuable for finding the critical value\nof the hopping parameter and for examining the size of supersymmetry breaking\nby the lattice discretisation. In this article we present an improved method\nfor the numerical analysis of supersymmetric Ward identities, which takes into\naccount the correlations between the various observables involved. We present\nthe first complete analysis of supersymmetric Ward identities in\n$\\mathcal{N}=1$ supersymmetric Yang-Mills theory with gauge group SU(3). The\nresults show that lattice artefacts scale to zero as $O(a^2)$ towards the\ncontinuum limit in agreement with theoretical expectations.",
        "positive": "Heavy quarkonium potential from Bethe-Salpeter wave function on the\n  lattice: We propose a novel method for the determination of the interquark potential\ntogether with quark \"kinetic mass'' $m_Q$ from the equal-time $Q\\bar{Q}$\nBethe-Salpeter (BS) amplitude in lattice QCD. Our approach allows us to\ncalculate spin-dependent $Q\\bar{Q}$ potentials, e.g. the spin-spin potential,\nas well. In order to investigate several systematic uncertainties on such\n$Q\\bar{Q}$ potentials, we carry out lattice QCD simulations using quenched\ngauge configurations generated with the single plaquette gauge action with\nthree different lattice spacings, $a \\approx$ 0.093, 0.068 and 0.047 fm, and\ntwo different physical volumes, $L \\approx$ 2.2 and 3.0 fm. For heavy quarks,\nwe employ the relativistic heavy quark (RHQ) action which can control large\ndiscretization errors introduced by large quark mass $m_Q$. The\nspin-independent central $Q\\bar{Q}$ potential for the charmonium system yields\nthe \"Coulomb plus linear'' behavior with good scaling and small volume\ndependence. We explore the quark mass dependence over the wide mass range from\nthe charm to beyond the bottom region, and then demonstrate that the\nspin-independent central $Q\\bar{Q}$ potential in the $m_Q \\to \\infty$ limit is\nfairly consistent with the static $Q\\bar{Q}$ potential obtained from Wilson\nloops. The spin-spin potential at finite quark mass provides a repulsive\ninteraction with a finite range, which becomes narrower as the quark mass\nincreases. We also discuss the applicability of the $1/m_Q$ expansion approach\nfor the spin-spin potential."
    },
    {
        "anchor": "On the Triviality of Textbook Quantum Electrodynamics: By adding a small, irrelevant four fermi interaction to the action of lattice\nQuantum Electrodynamics (QED), the theory can be simulated with massless quarks\nin a vacuum free of lattice monopoles. This allows an ab initio high precision,\ncontrolled study of the existence of \"textbook\" Quantum Electrodynamics with\nseveral species of fermions. The lattice theory possesses a second order chiral\nphase transition which we show is logarithmically trivial. The logarithms of\ntriviality, which modify mean field scaling laws, are pinpointed in several\nobservables. The result supports Landau's contention that perturbative QED\nsuffers from complete screening and would have a vanishing fine structure\nconstant in the absence of a cutoff.",
        "positive": "Moebius Algorithm for Domain Wall and GapDW Fermions: The M\\\"obius domain wall action \\cite{Brower:2004xi} is a generalization of\nShamir's action, which gives exactly the same overlap fermion lattice action as\nthe separation ($L_s$) between the domain walls is taken to infinity. The\nperformance advantages of the algorithm are presented for small ensembles of\nquenched, full QCD domain wall and Gap domain wall lattices\n\\cite{Vranas:2006zk}. In particular, it is shown that at the larger lattice\nspacings relevant to current dynamical simulations M\\\"obius fermions work well\ntogether with GapDWF, reducing $L_s$ by more than a factor of two. It is noted\nthat there is a precise map between the domain wall and effective overlap\naction at finite quark mass including finite $L_s$ chiral violations so that\nthe Ward-Takahashi identities for the axial and vector currents are exactly\nequivalent in the two formulations."
    },
    {
        "anchor": "Spontaneous chiral symmetry breaking in QCD:a finite-size scaling study\n  on the lattice: Spontaneous chiral symmetry breaking in QCD with massless quarks at infinite\nvolume can be seen in a finite box by studying, for instance, the dependence of\nthe chiral condensate from the volume and the quark mass. We perform a\nfeasibility study of this program by computing the quark condensate on the\nlattice in the quenched approximation of QCD at small quark masses. We carry\nout simulations in various topological sectors of the theory at several\nvolumes, quark masses and lattice spacings by employing fermions with an exact\nchiral symmetry, and we focus on observables which are infrared stable and free\nfrom mass-dependent ultraviolet divergences. The numerical calculation is\ncarried out with an exact variance-reduction technique, which is designed to be\nparticularly efficient when spontaneous symmetry breaking is at work in\ngenerating a few very small low-lying eigenvalues of the Dirac operator. The\nfinite-size scaling behaviour of the condensate in the topological sectors\nconsidered agrees, within our statistical accuracy, with the expectations of\nthe chiral effective theory. Close to the chiral limit we observe a detailed\nagreement with the first Leutwyler-Smilga sum rule. By comparing the mass, the\nvolume and the topology dependence of our results with the predictions of the\nchiral effective theory, we extract the corresponding low-energy constant.",
        "positive": "Large N lattice gauge theory: Wilson loops in large N gauge theory exhibit a weak to strong coupling\ntransition as the loop is dilated. A multiplicative matrix model captures the\nuniversal behavior associated with this transition. A universal scaling\nfunction is obtained in a double scaling limit. Numerical studies show that\nboth large N QCD in three dimensions and the SU(N) principal chiral model in\ntwo dimensions are in the same universality class."
    },
    {
        "anchor": "$K \\to \u03c0\u03c0$ Decays with Domain Wall Fermions: Towards Physical\n  Results: We are using domain wall fermions to study $K \\to \\pi \\pi$ matrix elements by\nmeasuring $K \\to \\pi$ and $K \\to 0$ matrix elements on the lattice and\nemploying chiral perturbation theory to relate these to the desired physical\nresult. The residual chiral symmetry breaking of domain wall fermions with a\nfinite extent in the fifth dimension impacts these measurements. Using the\nWard-Takahashi identities, we investigate residual chiral symmetry breaking\neffects for divergent quantities and study pathologies of the quenched\napproximation for small quark mass. We then discuss the $\\Delta S = 1$ operator\n$O_2$, where chiral symmetry is vital for the subtraction of unphysical\neffects.",
        "positive": "Fluctuation without dissipation: Microcanonical Langevin Monte Carlo: Stochastic sampling algorithms such as Langevin Monte Carlo are inspired by\nphysical systems in a heat bath. Their equilibrium distribution is the\ncanonical ensemble given by a prescribed target distribution, so they must\nbalance fluctuation and dissipation as dictated by the fluctuation-dissipation\ntheorem. In contrast to the common belief, we show that the\nfluctuation-dissipation theorem is not required because only the configuration\nspace distribution, and not the full phase space distribution, needs to be\ncanonical. We propose a continuous-time Microcanonical Langevin Monte Carlo\n(MCLMC) as a dissipation-free system of stochastic differential equations\n(SDE). We derive the corresponding Fokker-Planck equation and show that the\nstationary distribution is the microcanonical ensemble with the desired\ncanonical distribution on configuration space. We prove that MCLMC is ergodic\nfor any nonzero amount of stochasticity, and for smooth, convex potentials, the\nexpectation values converge exponentially fast. Furthermore, the deterministic\ndrift and the stochastic diffusion separately preserve the stationary\ndistribution. This uncommon property is attractive for practical\nimplementations as it implies that the drift-diffusion discretization schemes\nare bias-free, so the only source of bias is the discretization of the\ndeterministic dynamics. We applied MCLMC on a lattice $\\phi^4$ model, where\nHamiltonian Monte Carlo (HMC) is currently the state-of-the-art integrator. For\nthe same accuracy, MCLMC converges 12 times faster than HMC on an $8\\times8$\nlattice. On a $64\\times64$ lattice, it is already 32 times faster. The trend is\nexpected to persist to larger lattices, which are of particular interest, for\nexample, in lattice quantum chromodynamics."
    },
    {
        "anchor": "Supersymmetric corrections to $\u03b5^\\prime /\u03b5at the leading\n  order in QCD and QED: We study the corrections to $\\epsilon^\\prime /\\epsilon$ in the minimal\nsupersymmetric model at the leading order in QCD and QED. Supersymmetry can\nincrease the standard model prediction for $\\epsilon^\\prime /\\epsilon$ by at\nmost 40\\% for $m_t=174$ GeV, an enhancement which is indistinguishable from the\npresent theoretical uncertainties. The most conspicuous effect of supersymmetry\nis a strong depletion of $\\epsilon^\\prime /\\epsilon$. For certain choices of\nsupersymmetric parameters, vanishing and even small negative values of\n$\\epsilon^\\prime /\\epsilon$ can be obtained for the top quark in the CDF range.",
        "positive": "The Propagators of Gauge Bosons on a lattice: We analyse the problem of the generation of mass in the gauge boson sector on\nthe (Planck) lattice. We obtain a dynamical scenario quite similar to the\npopular Higgs-mechanism, with the important difference that no Higgs-type\nexcitation is present in our theory. By fixing the mass of the $Z^\\circ$-boson\nand the renormalized gauge couplings at their experimental values, we get for\nthe top quark mass $m_t\\simeq 149$GeV and for the $\\rho$-parameter the very\nsmall value $\\rho\\sim 10^{-6}$."
    },
    {
        "anchor": "Non abelian Bianchi identities, monopoles and gauge invariance: A direct connection is proved between the Non-Abelian Bianchi Identities and\nthe Abelian Bianchi identities for the 't Hooft tensor in a generic gauge; the\nexistence of a magnetic current is related to the violation of NABI's. Using\nthis relation it is shown that not all gauges are equivalent to detect\nmonopoles on the lattice, that e.g. the Maximal Abelian Gauge is a legitimate\nchoice while the Landau gauge is not. Nevertheless monopole condensation is\nfound to be a gauge invariant property.",
        "positive": "Testing and tuning symplectic integrators for Hybrid Monte Carlo\n  algorithm in lattice QCD: We examine a new 2nd order integrator recently found by Omelyan et al. The\nintegration error of the new integrator measured in the root mean square of the\nenergy difference, $\\bra\\Delta H^2\\ket^{1/2}$, is about 10 times smaller than\nthat of the standard 2nd order leapfrog (2LF) integrator. As a result, the step\nsize of the new integrator can be made about three times larger. Taking into\naccount a factor 2 increase in cost, the new integrator is about 50% more\nefficient than the 2LF integrator. Integrating over positions first, then\nmomenta, is slightly more advantageous than the reverse. Further parameter\ntuning is possible. We find that the optimal parameter for the new integrator\nis slightly different from the value obtained by Omelyan et al., and depends on\nthe simulation parameters. This integrator could also be advantageous for the\nTrotter-Suzuki decomposition in Quantum Monte Carlo."
    },
    {
        "anchor": "Heavy-light spectrum and decay constant from NRQCD with two flavors of\n  dynamical quarks: We report on a study of B mesons on N_f = 2 full QCD configurations using an\nRG-improved gauge action, NRQCD heavy quark action and tadpole-improved clover\nlight quark action. Results on the heavy-light spectrum and the decay constants\nfrom 16^3x32 lattices at a^{-1} ~ 1.5 GeV are presented, and compared with\nquenched results obtained with the same action combination at matching lattice\nspacings.",
        "positive": "Chiral transition, eigenmode localisation and Anderson-like models: We discuss chiral symmetry restoration and eigenmode localisation in\nfinite-temperature QCD by looking at the lattice Dirac operator as a random\nHamiltonian. We argue that the features of QCD relevant to both phenomena are\nthe presence of order in the Polyakov line configuration, and the correlations\nthat this induces between spatial links across time slices. This ties the fate\nof chiral symmetry and of localisation of the lowest Dirac eigenmodes to the\nconfining properties of the theory. We then show numerical results obtained in\na QCD-inspired Anderson-like toy model, derived by radically simplifying the\nQCD dynamics while keeping the important features mentioned above. The toy\nmodel reproduces all the important qualitative aspects of chiral symmetry\nbreaking and localisation in QCD, thus supporting the central role played by\nthe confinement/deconfinement transition in triggering both phenomena."
    },
    {
        "anchor": "Updated Lattice Results for Parton Distributions: We provide an analysis of the x-dependence of the bare unpolarized, helicity\nand transversity iso-vector parton distribution functions (PDFs) from lattice\ncalculations employing (maximally) twisted mass fermions. The x-dependence of\nthe calculated PDFs resembles the one of the phenomenological\nparameterizations, a feature that makes this approach very promising.\nFurthermore, we apply momentum smearing for the relevant matrix elements to\ncompute the lattice PDFs and find a large improvement factor when compared to\nconventional Gaussian smearing. This allows us to extend the lattice\ncomputation of the distributions to higher values of the nucleon momentum,\nwhich is essential for the prospects of a reliable extraction of the PDFs in\nthe future.",
        "positive": "Stochastic Renormalization Group and Gradient Flow in Scalar Field\n  Theory: Recently, the connections between gradient flow and renormalization group\nhave been explored analytically and numerically. Gradient flow (when modified\nby a field rescaling) can be characterized as a continuous blocking\ntransformation. In this work, we draw a connection between gradient flow and\nfunctional renormalization group by describing how FRG can be represented by a\nstochastic process, and how the stochastic observables relate to gradient flow\nobservables. The relation implies correlator scaling formulae that can be\napplied numerically in lattice simulations. We present preliminary results on\nanomalous dimensions obtained from such measurements in the context of\n3-dimensional lattice $\\phi^4$ theory."
    },
    {
        "anchor": "Probing the chiral limit of M_pi and f_pi in 2+1 flavor QCD with domain\n  wall fermions from QCDOC: We present results for the pseudoscalar meson masses and decay constants on\n2+1 flavor DWF configurations with different sea quark masses and an inverse\nlattice spacing of 1.6(1) GeV, with a focus on chiral fits at small quark\nmasses. The calculation is done on 16^3x32x8 lattices generated with the DBW2\ngauge action.",
        "positive": "Cutoff effects of Wilson fermions on the QCD equation of state to O(g^2): We compute the O(g^2) contribution to the thermodynamic pressure for Wilson\nfermions in the standard, the twisted mass, and clover improved formulation in\nlattice perturbation theory, including finite mass effects. We compare the\ncontinuum approaches of these discretizations for the massive ideal and\ninteracting gas. In all cases, for N_t \\geq 8 cutoff effects of Wilson type\nfermions are comparable to those of staggered fermions, but asymptotic scaling\nrequires $N_\\tau>10$."
    },
    {
        "anchor": "Analytical computation of the magnetization probability density function\n  for the harmonic 2D XY model: The probability density function (PDF) of some global average quantity plays\na fundamental role in critical and highly correlated systems. We explicitly\ncompute this quantity as a function of the magnetization for the two\ndimensional XY model in its harmonic approximation. Numerical simulations and\nperturbative results have shown a Gumbel-like shape of the PDF, in spite of the\nfact that the average magnetization is not an extreme variable. Our analytical\nresult allows to test both perturbative analytical expansions and also\nnumerical computations performed previously. Perfect agreement is found for the\nfirst moments of the PDF. Also for large volume and in the high temperature\nlimit the distribution becomes Gaussian, as it should be. In the low\ntemperature regime its numerical evaluation is compatible with a Gumbel\ndistribution.",
        "positive": "A new method for suppressing excited-state contaminations on the nucleon\n  form factors: One of the most challenging tasks in lattice calculations of baryon form\nfactors is the analysis and control of excited-state contaminations. Taking the\nisovector axial form factors of the nucleon as an example, both a dispersive\nrepresentation and a calculation in chiral effective field theory show that the\nexcited-state contributions become dominant at fixed source-sink separation\nwhen the axial current is spatially distant from the nucleon source location.\nWe address this effect with a new method in which the axial current is\nlocalized by a Gaussian wave-packet and apply it on a CLS ensemble with\n$N_f=2+1$ flavors of O($a$) improved Wilson fermions with a pion mass of\n$m_\\pi=200\\,$MeV."
    },
    {
        "anchor": "Parton distribution functions from lattice QCD using Bayes-Gauss-Fourier\n  transforms: We present a new method, based on Gaussian process regression, for\nreconstructing the continuous $x$-dependence of parton distribution functions\n(PDFs) from quasi-PDFs computed using lattice QCD. We examine the origin of the\nunphysical oscillations seen in current lattice calculations of quasi-PDFs and\ndevelop a nonparametric fitting approach to take the required Fourier\ntransform. The method is tested on one ensemble of maximally twisted mass\nfermions with two light quarks. We find that with our approach oscillations of\nthe quasi-PDF are drastically reduced. However, the final effect on the\nlight-cone PDFs is small. This finding suggests that the deviation seen between\ncurrent lattice QCD results and phenomenological determinations cannot be\nattributed solely on the Fourier transform.",
        "positive": "Does the complex Langevin method give unbiased results?: We investigate whether the stationary solution of the Fokker-Planck equation\nof the complex Langevin algorithm reproduces the correct expectation values.\nWhen the complex Langevin algorithm for an action $S(x)$ is convergent, it\nproduces an equivalent complex probability distribution $P(x)$ which ideally\nwould coincide with $e^{-S(x)}$. We show that the projected Fokker-Planck\nequation fulfilled by $P(x)$ may contain an anomalous term whose form is made\nexplicit. Such term spoils the relation $P(x)=e^{-S(x)}$, introducing a bias in\nthe expectation values. Through the analysis of several periodic and\nnon-periodic one-dimensional problems, using either exact or numerical\nsolutions of the Fokker-Planck equation on the complex plane, it is shown that\nthe anomaly is present quite generally. In fact, an anomaly is expected\nwhenever the Langevin walker needs only a finite time to go to infinity and\ncome back, and this is the case for typical actions. We conjecture that the\nanomaly is the rule rather than the exception in the one-dimensional case,\nhowever, this could change as the number of variables involved increases."
    },
    {
        "anchor": "Critical properties of 2D Z(N) vector models for N>4: We investigate the critical properties of two-dimensional Z(N) vector models\nfor N larger than 4. In particular, critical points of the two phase\ntransitions are located and some critical indices are determined. We study also\nthe behavior of the helicity modulus and the dependence of the critical points\non N.",
        "positive": "$x$-dependence reconstruction of pion and kaon PDFs from Mellin moments: We present a calculation of the connected-diagram contributions to the first\nthree non-trivial Mellin moments for the pion and kaon, extracted using local\noperators with up to 3 covariant derivatives. We use one ensemble of gauge\nconfigurations with two degenerate light, a strange and a charm quark\n($N_f$=2+1+1) of maximally twisted mass fermions with clover improvement. The\nensemble has a pion mass $\\sim$260 MeV, and a kaon mass $\\sim$530 MeV. We\nreconstruct the $x$-dependence of the PDFs via fits to our results, and find\nthat our lattice data favor a $(1-x)^2$-behavior in the large-$x$ region for\nboth the pion and kaon PDFs. We integrate the reconstructed PDFs to extract the\nhigher moments, $\\langle x^n \\rangle$, with $4 \\leq n \\leq 6$. Finally, we\ncompare the pion and kaon PDFs, as well as the ratios of their Mellin moments,\nto address the effect of SU(3) flavor symmetry breaking."
    },
    {
        "anchor": "Nucleon isovector charges and twist-2 matrix elements with $N_f=2+1$\n  dynamical Wilson quarks: We present results from a lattice QCD study of nucleon matrix elements at\nvanishing momentum transfer for local and twist-2 isovector operator\ninsertions. Computations are performed on gauge ensembles with\nnon-perturbatively improved $N_f=2+1$ Wilson fermions, covering four values of\nthe lattice spacing and pion masses down to $M_\\pi\\approx200$MeV. Several\nsource-sink separations (typically ~1.0fm to ~1.5fm) allow us to assess\nexcited-state contamination. Results on individual ensembles are obtained from\nsimultaneous two-state fits across all observables and all available\nsource-sink separations with the energy gap as a common fit parameter.\nRenormalization has been performed non-perturbatively using the\nRome-Southampton method for all but the finest lattice spacing for which an\nextrapolation has been used. Physical results are quoted in the $\\overline{MS}$\nscheme at a scale of $\\mu=2$GeV and are obtained from a combined chiral,\ncontinuum and finite-size extrapolation. For the nucleon isovector axial,\nscalar and tensor charges we find physical values of\n$g_A^{u-d}=1.242(25)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+00}{-31})_\\text{sys}$,\n$g_S^{u-d}=1.13(11)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+07}{-06})_\\text{sys}$ and\n$g_T^{u-d}=0.965(38)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+13}{-41})_\\text{sys}$,\nrespectively, where individual systematic errors in each direction from the\nchiral, continuum and finite-size extrapolation have been added in quadrature.\nOur final results for the isovector average quark momentum fraction and the\nisovector helicity and transversity moments are given by $\\langle\nx\\rangle_{u-d}=0.180(25)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+14}{-06})_\\text{sys}$,\n$\\langle x\\rangle_{\\Delta u-\\Delta\nd}=0.221(25)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+10}{-00})_\\text{sys}$ and\n$\\langle x\\rangle_{\\delta u-\\delta\nd}=0.212(32)_\\text{stat}(\\genfrac{}{}{0pt}{2}{+20}{-10})_\\text{sys}$,\nrespectively.",
        "positive": "Electrical conductivity of the quark-gluon plasma across the\n  deconfinement transition: A lattice calculation is presented for the electrical conductivity of the QCD\nplasma with 2+1 dynamical flavours at nonzero temperature. We employ the\nconserved lattice current on anisotropic lattices using a tadpole-improved\nclover action and study the behaviour of the conductivity over a wide range of\ntemperatures, both below and above the deconfining transition. The conductivity\nis extracted from a spectral-function analysis using the Maximal Entropy Method\nand a discussion of its systematics is provided."
    },
    {
        "anchor": "Running coupling constant from position-space current-current\n  correlation functions in three-flavor lattice QCD: In this Letter, we provide a determination of the coupling constant in\nthree-flavor quantum chromodynamics (QCD),\n$\\alpha^{\\overline{\\mathrm{MS}}}_s(\\mu)$, for $\\overline{\\mathrm{MS}}$\nrenormalization scales $\\mu \\in (1,\\,2)$ GeV. The computation uses gauge field\nconfiguration ensembles with $\\mathcal{O}(a)$-improved Wilson-clover fermions\ngenerated by the Coordinated Lattice Simulations (CLS) consortium. Our approach\nis based on current-current correlation functions and has never been applied\nbefore in this context. We convert the results perturbatively to the QCD\n$\\Lambda$-parameter and obtain $\\Lambda_{\\overline{\\mathrm{MS}}}^{N_f=3} = 342\n\\pm 17$ MeV, which agrees with the world average published by the Particle Data\nGroup and has competing precision. The latter was made possible by a unique\ncombination of state-of-the-art CLS ensembles with very fine lattice spacings,\nfurther reduction of discretization effects from a dedicated numerical\nstochastic perturbation theory simulation, combining data from vector and\naxial-vector channels and matching to high-order perturbation theory.",
        "positive": "High-Temperature Series Analyses of the Classical Heisenberg and XY\n  Model: Although there is now a good measure of agreement between Monte Carlo and\nhigh-temperature series expansion estimates for Ising ($n=1$) models, published\nresults for the critical temperature from series expansions up to 12{\\em th}\norder for the three-dimensional classical Heisenberg ($n=3$) and XY ($n=2$)\nmodel do not agree very well with recent high-precision Monte Carlo estimates.\nIn order to clarify this discrepancy we have analyzed extended high-temperature\nseries expansions of the susceptibility, the second correlation moment, and the\nsecond field derivative of the susceptibility, which have been derived a few\nyears ago by L\\\"uscher and Weisz for general $O(n)$ vector spin models on\n$D$-dimensional hypercubic lattices up to 14{\\em th} order in $K \\equiv J/k_B\nT$. By analyzing these series expansions in three dimensions with two different\nmethods that allow for confluent correction terms, we obtain good agreement\nwith the standard field theory exponent estimates and with the critical\ntemperature estimates from the new high-precision MC simulations. Furthermore,\nfor the Heisenberg model we reanalyze existing series for the susceptibility on\nthe BCC lattice up to 11{\\em th} order and on the FCC lattice up to 12{\\em th}\norder."
    },
    {
        "anchor": "Flux tubes in the SU(3) vacuum: We analyze the distribution of the chromoelectric field generated by a static\nquark-antiquark pair in the SU(3) vacuum. We find that the transverse profile\nof the flux tube resembles the dual version of the Abrikosov vortex field\ndistribution and give an estimate of the London penetration length in the\nconfined vacuum.",
        "positive": "Radial Lattice Quantization of 3D $\u03c6^4$ Field Theory: The quantum extension of classical finite elements, referred to as quantum\nfinite elements ({\\bf QFE})~\\cite{Brower:2018szu,Brower:2016vsl}, is applied to\nthe radial quantization of 3d $\\phi^4$ theory on a simplicial lattice for the\n$\\mathbb R \\times \\mathbb S^2$ manifold. Explicit counter terms to cancel the\none- and two-loop ultraviolet defects are implemented to reach the quantum\ncontinuum theory. Using the Brower-Tamayo~\\cite{Brower:1989mt} cluster Monte\nCarlo algorithm, numerical results support the QFE ansatz that the critical\nconformal field theory (CFT) is reached in the continuum with the full\nisometries of $\\mathbb R \\times \\mathbb S^2$ restored. The Ricci curvature\nterm, while technically irrelevant in the quantum theory, is shown to\ndramatically improve the convergence opening, the way for high precision Monte\nCarlo simulation to determine the CFT data: operator dimensions, trilinear OPE\ncouplings and the central charge."
    },
    {
        "anchor": "A New Action for Heavy Lattice Fermions: I describe a unified formalism for lattice fermions, in which the\nrelativistic action of Wilson and the nonrelativistic and static actions appear\nas special cases. It is valid at all values of $m_q a$, including $m_q a\n\\approx 1$. In the limit $m_q a \\ll 1 $, the formulation reduces to the light\nquark action of Wilson. In the limit $m_q a \\gg 1 $, the formulation reduces to\nthe nonrelativistic action of Thacker and Lepage, and to the static action of\nEichten.",
        "positive": "The 2-dimensional non-linear sigma-model on a random latice: The O(n) non-linear $\\sigma$-model is simulated on 2-dimensional regular and\nrandom lattices. We use two different levels of randomness in the construction\nof the random lattices and give a detailed explanation of the geometry of such\nlattices. In the simulations, we calculate the mass gap for $n=3, 4$ and 8,\nanalysing the asymptotic scaling of the data and computing the ratio of Lambda\nparameters $\\Lambda_{\\rm random}/\\Lambda_{\\rm regular}$. These ratios are in\nagreement with previous semi-analytical calculations. We also numerically\ncalculate the topological susceptibility by using the cooling method."
    },
    {
        "anchor": "Numerical Study of c>1 Matter Coupled to Quantum Gravity: We present the results of a numerical simulation aimed at understanding the\nnature of the `c = 1 barrier' in two dimensional quantum gravity. We study\nmultiple Ising models living on dynamical $\\phi^3$ graphs and analyse the\nbehaviour of moments of the graph loop distribution. We notice a universality\nat work as the average properties of typical graphs from the ensemble are\ndetermined only by the central charge. We further argue that the qualitative\nnature of these results can be understood from considering the effect of\nfluctuations about a mean field solution in the Ising sector.",
        "positive": "Global Structure of Conformal Theories in the SU(3) Gauge Theory: We investigate SU(3) gauge theories in four dimensions with Nf fundamental\nfermions, on a lattice using the Wilson fermion. Clarifying the vacuum\nstructure in terms of Polyakov loops in spatial directions and properties of\ntemporal propagators using a new method \"local analysis\", we conjecture that\nthe \"conformal region\" exists together with the confining region and the\ndeconfining region in the phase structure parametrized by beta and K, both in\nthe cases of the large Nf QCD within the conformal window (referred as\nConformal QCD) with an IR cutoff and small Nf QCD at T/Tc>1 with Tc being the\nchiral transition temperature (referred as High Temperature QCD).\n  Our numerical simulation on a lattice of the size 16^3 x 64 shows the\nfollowing evidence of the conjecture. In the conformal region we find the\nvacuum is the nontrivial Z(3) twisted vacuum modified by non-perturbative\neffects and temporal propagators of meson behave at large t as a power-law\ncorrected Yukawa-type decaying form. The transition from the conformal region\nto the deconfining region or the confining region is a sharp transition between\ndifferent vacua and therefore it suggests a first order transition both in\nConformal QCD and in High Temperature QCD.\n  Within our fixed lattice simulation, we find that there is a precise\ncorrespondence between Conformal QCD and High Temperature QCD in the temporal\npropagators under the change of the parameters Nf and T/Tc respectively. In\nparticular, we find the correspondence between Conformal QCD with Nf = 7 and\nHigh Temperature QCD with Nf=2 at T ~ 2 Tc being in close relation to a meson\nunparticle model. From this we estimate the anomalous mass dimension gamma* =\n1.2 (1) for Nf=7. We also show that the asymptotic state in the limit T/Tc -->\ninfty is a free quark state in the Z(3) twisted vacuum."
    },
    {
        "anchor": "Lattice study of pion-pion scattering using Nf=2+1 Wilson improved\n  quarks with masses down to their physical values: We use 2HEX smeared gauge configurations generated with an\n$\\mathrm{N}_\\mathrm{f}\\mathrm{=2+1}$ clover improved Wilson action to\ninvestigate $\\pi\\pi$ scattering in the $\\rho$ channel. The range of lattice\nspacings (0.054 to 0.12 fm) and space-like extents (32 and 48) allows us to\nextract the scattering parameters through the volume dependence of the\n$\\pi\\pi$-state energies according to L\\\"uscher's formalism. The pion masses\n(134 to 300 MeV) are light enough to allow the decay of the rho and the level\nrepulsion observed indicates that our data are sensitive to the interaction. We\nanalyse our data with a multi-channel GEVP variational formula. Our results are\nin good agreement with the experimental values and consistent with a weak pion\nmass dependence of the $\\rho\\pi\\pi$ coupling constant.",
        "positive": "Finite-volume and thermal effects in the leading-HVP contribution to\n  muonic $(g-2)$: The leading finite-volume and thermal effects, arising in numerical lattice\nQCD calculations of $a^{\\text{HVP,LO}}_\\mu \\equiv (g-2)^{\\text{HVP,LO}}_\\mu/2$,\nare determined to all orders with respect to the interactions of a generic,\nrelativistic effective field theory of pions. In contrast to earlier work based\nin the finite-volume Hamiltonian, the results presented here are derived by\nformally summing all Feynman diagrams contributing to the Euclidean\nelectromagnetic-current two-point function, with any number of internal pion\nloops and interaction vertices. As was already found in our previous\npublication, the leading finite-volume corrections to $a^{\\text{HVP,LO}}_\\mu$\nscale as $\\exp[- m L]$ where $m$ is the pion mass and $L$ is the length of the\nthree periodic spatial directions. In this work we additionally control the two\nsub-leading exponentials, scaling as $\\exp[- \\sqrt{2} m L]$ and $\\exp[-\n\\sqrt{3} m L]$. As with the leading term, the coefficient of these is given by\nthe forward Compton amplitude of the pion, meaning that all details of the\neffective theory drop out of the final result. Thermal effects are additionally\nconsidered, and found to be sub-percent-level for typical lattice calculations.\nAll finite-volume corrections are presented both for $a^{\\text{HVP,LO}}_\\mu$\nand for each time slice of the two-point function, with the latter expected to\nbe particularly useful in correcting small to intermediate current separations,\nfor which the series of exponentials exhibits good convergence."
    },
    {
        "anchor": "Lattice QCD at finite temperature and density: We study the phase structure of QCD at finite temperature and density by\nnumerical simulations on a lattice. The most important point for the numerical\nstudy at finite density is treatment of the sign problem. We propose a method\nto avoid the sign problem, which is based on a cumulant expansion of the\ncomplex phase in the density of state method combined with the reweighting\nmethod. Using the method, we study the critical point terminating a first order\nphase transition line in lattice QCD at high temperature and density.",
        "positive": "The phase diagram of heavy dense QCD with complex Langevin simulations: The sign problem of QCD prevents standard lattice simulations to determine\nthe phase diagram of strong interactions with a finite chemical potential\ndirectly. Complex Langevin simulations provide an alternative method to sample\npath integrals with complex weights. We report on our ongoing project to\ndetermine the phase diagram of QCD in the limit of heavy quarks (HDQCD) using\nComplex Langevin simulations."
    },
    {
        "anchor": "Nucleon Spin Structures from Lattice QCD: Flavor Singlet Axial and\n  Tensor Charges: The flavor singlet axial and tensor charges of the nucleon are calculated in\nlattice QCD. We find $\\Delta\\Sigma=\\Delta u+\\Delta d+\\Delta\ns=+0.638(54)-0.347(46)-0.109(30) = +0.18(10)$ for the axial charge and\n$\\delta\\Sigma=\\delta u+\\delta d+\\delta s=+0.839(60)-0.231(55)-0.046(34) =\n+0.562(88)$ for the tensor charge. The result for the axial charge shows\nreasonable agreement with the experiment and that for the tensor charge is the\nfirst prediction from lattice QCD before experimental measurements.",
        "positive": "Investigating the conformal behaviour of SU(2) with one adjoint Dirac\n  flavor: We present a major update on our investigations of SU(2) gauge theory with\none Dirac flavor in the adjoint representation on the lattice. In particular we\nconsider larger volumes, as well as four different values of the gauge\ncoupling. We provide results for the spectrum including gluonic, fermionic, and\nhybrid observables, Polyakov loops, and the anomalous dimension of the\nfermionic condensate from the Dirac mode number. These data confirm that the\ntheory is close to the lower boundary of the conformal window for adjoint\nfermions. Our investigations provide important insights regarding the\nrealization of different infrared scenarios that have been conjectured for this\ntheory."
    },
    {
        "anchor": "Discrete aspects of continuous symmetries in the tensorial formulation\n  of Abelian gauge theories: We show that standard identities and theorems for lattice models with $U(1)$\nsymmetry get re-expressed discretely in the tensorial formulation of these\nmodels. We explain the geometrical analogy between the continuous lattice\nequations of motion and the discrete selection rules of the tensors. We\nconstruct a gauge-invariant transfer matrix in arbitrary dimensions. We show\nthe equivalence with its gauge-fixed version in a maximal temporal gauge and\nexplain how a discrete Gauss's law is always enforced. We propose a\nnoise-robust way to implement Gauss's law in arbitrary dimensions. We\nreformulate Noether's theorem for global, local, continuous or discrete Abelian\nsymmetries: for each given symmetry, there is one corresponding tensor\nredundancy. We discuss semi-classical approximations for classical solutions\nwith periodic boundary conditions in two solvable cases. We show the\ncorrespondence of their weak coupling limit with the tensor formulation after\nPoisson summation. We briefly discuss connections with other approaches and\nimplications for quantum computing.",
        "positive": "Supermultiplets in N=1 SUSY SU(2) Yang-Mills Theory: We study $\\mathcal{N}=1$ supersymmetric Yang-Mills theory (SYM) on the\nlattice. The non-perturbative nature of supersymmetric field theories is still\nlargely unknown. Similarly to QCD, SYM is confining and contains strongly bound\nstates. Applying the variational method together with different smearing\ntechniques we extract masses of the lightest bound states such as gluino-glue,\nglueball and mesonic states. As these states should form supermultiplets, this\nstudy allows to check whether SYM remains supersymmetric also on the quantum\nlevel."
    },
    {
        "anchor": "Color singlet and adjoint free energy at finite temperature: We study correlation functions of static quark-antiquark pairs in SU(2) gauge\ntheory at finite temperature. By measuring Polyakov loop correlators and\ntemporal Wilson loops with APE smearing of spatial links we are able to give\nconsistent definitions of the singlet and adjoint free energies at short\ndistances, where the notion of these free energies is meaningful. APE smearing\nprocedure allows to achieve a high degree of overlap in the singlet channel and\nto reconstruct the adjoint part from the color averaged and singlet free\nenergy.",
        "positive": "Finite Temperature QCD with Domain Wall Fermions: Domain wall fermions are a new lattice fermion formulation which preserves\nthe full chiral symmetry of the continuum at finite lattice spacing, up to\nterms exponentially small in an extra parameter. We discuss the main features\nof the formulation and its application to study of QCD with two light fermions\nof equal mass. We also present numerical studies of the two flavor QCD\nthermodynamics with aT = 1/4."
    },
    {
        "anchor": "Interquark potential with finite quark mass from lattice QCD: We present an investigation of the interquark potential determined from the\nqq^bar Bethe-Salpeter (BS) amplitude for heavy quarkonia in lattice QCD. The\nqq^bar potential at finite quark mass m_q can be calculated from the equal-time\nand Coulomb gauge BS amplitude through the effective Schr\\\"odinger equation.\nThe definition of the potential itself requires information about a kinetic\nmass of the quark. We then propose a self-consistent determination of the quark\nkinetic mass on the same footing. To verify the proposed method, we perform\nquenched lattice QCD simulations with a relativistic heavy quark action at a\nlattice cutoff of 1/a ~ 2.1 GeV in a range of the quark kinetic mass, 1.0 {\\ge}\nm_q {\\ge} 3.6 GeV. Our numerical results show that the qq^bar potential in the\ninfinitely heavy quark limit (m_q -> {\\infty}) is fairly consistent with the\nconventional one obtained from Wilson loops. The quark mass dependence of the\nqq^bar potential and the spin-spin potential are also examined.",
        "positive": "Electromagnetic form factor of pion from N_f=2+1 dynamical flavor QCD: We present a calculation of the electromagnetic form factor of the pion in\n$N_f=2+1$ flavor lattice QCD. Calculations are made on the PACS-CS gauge field\nconfigurations generated using Iwasaki gauge action and Wilson-clover quark\naction on a $32^3\\times64$ lattice volume with the lattice spacing estimated as\n$a=0.0907(13)$ fm at the physical point. Measurements of the form factor are\nmade using the technique of partially twisted boundary condition to reach small\nmomentum transfer as well as periodic boundary condition with integer momenta.\nAdditional improvements including random wall source techniques and a judicious\nchoice of momenta carried by the incoming and outgoing quarks are employed for\nerror reduction. Analyzing the form factor data for the pion mass at $M_\\pi\n\\approx 411$ MeV and 296 MeV, we find that the NNLO SU(2) chiral perturbation\ntheory fit yields $<r^2>=0.441 \\pm 0.046 {\\rm fm}^2$ for the pion charge radius\nat the physical pion mass. Albeit the error is quite large, this is consistent\nwith the experimental value of $0.452\\pm 0.011 {\\rm fm}^2$. Below $M_\\pi\\approx\n300$ MeV, we find that statistical fluctuations in the pion two- and\nthree-point functions become too large to extract statistically meaningful\naverages on a $32^3$ spatial volume. We carry out a sample calculation on a\n$64^4$ lattice with the quark masses close to the physical point, which\nsuggests that form factor calculations at the physical point become feasible by\nenlarging lattice sizes to $M_\\pi L\\approx 4$."
    },
    {
        "anchor": "$D\\to\u03c0$ and $D\\to K$ semileptonic form factors with $N_f=2+1+1$\n  twisted mass fermions: We present a lattice determination of the vector and scalar form factors of\nthe $D\\to\\pi(K)\\ell\\nu$ semileptonic decays, which are relevant for the\nextraction of the CKM matrix elements $|V_{cd}|$ and $|V_{cs}|$ from\nexperimental data. Our analysis is based on the gauge configurations produced\nby the European Twisted Mass Collaboration with $N_f=2+1+1$ flavors of\ndynamical quarks. We simulated at three different values of the lattice spacing\nand with pion masses as small as 210 MeV. The matrix elements of both vector\nand scalar currents are determined for a plenty of kinematical conditions in\nwhich parent and child mesons are either moving or at rest. Lorentz symmetry\nbreaking due to hypercubic effects is clearly observed in the data and included\nin the decomposition of the current matrix elements in terms of additional form\nfactors. After the extrapolations to the physical pion mass and to the\ncontinuum limit the vector and scalar form factors are determined in the whole\nkinematical region from $q^2 = 0$ up to $q^2_{\\rm max} = (M_D - M_{\\pi(K)})^2$\naccessible in the experiments, obtaining a good overall agreement with\nexperiments, except in the region at high values of $q^2$ where some deviations\nare visible.",
        "positive": "Kaon Mixing Beyond the Standard Model: We report on an ongoing calculation of hadronic matrix elements needed to\nparameterize K-Kbar mixing in generic BSM scenarios, using domain wall fermions\n(DWF) at two lattice spacings. Recent work by the SWME collaboration shows a\nsignificant disagreement with our previous results for two of these quantities.\nSince the origin of this disagreement is unknown, it is important to reduce the\nvarious uncertainties. In this work, we are using N_f=2+1 DWF with Iwasaki\ngauge action at inverse lattice spacings of 2.31 and 1.75 GeV, with multiple\nunitary pions on each ensemble, the lightest being 290 and 330 MeV on the finer\nand coarser of the two ensembles respectively. This extends previous work by\nthe addition of a second lattice spacing (a^{-1}\\approx 1.75 GeV).\nRenormalization is carried out non-perturbatively in the RI/MOM scheme and\nconverted perturbatively to MSbar."
    },
    {
        "anchor": "One Flavour QCD as an analogue computer for SUSY: We numerically study QCD with a single quark flavour on the lattice probing\npredictions from effective field theories that are equivalent to minimal\nsuper-symmetric Yang-Mills theory in the large $N_c$ limit. The hadronic\nspectrum including excited states is analysed using one gauge coupling and\nseveral physical volumes and fermion masses. We use the LapH method and also\ncompute disconnected diagrams. Lattice simulations with an odd number of Wilson\nfermions give rise to regions of configuration space with a negative fermionic\nweight entailing a sign problem. We perform a detailed analysis on the spectrum\nof the Wilson-Dirac operator and report on observed cases of a negative fermion\ndeterminant in our ensembles.",
        "positive": "The Savvidy ``ferromagnetic vacuum'' in three-dimensional lattice gauge\n  theory: The vacuum effective potential of three-dimensional SU(2) lattice gauge\ntheory in an applied color-magnetic field is computed over a wide range of\nfield strengths. The background field is induced by an external current, as in\ncontinuum field theory. Scaling and finite volume effects are analyzed\nsystematically. The first evidence from lattice simulations is obtained of the\nexistence of a nontrivial minimum in the effective potential. This supports a\n``ferromagnetic'' picture of gluon condensation, proposed by Savvidy on the\nbasis of a one-loop calculation in (3+1)-dimensional QCD."
    },
    {
        "anchor": "Toward extracting scattering phase shift from integrated correlation\n  function: In present work, a relation that connects the integrated correlation function\nof a trapped two-particle system to infinite volume particles scattering phase\nshift is derived. It has the potential to provide an alternative approach for\nextracting two-particle scattering phase shift from integrated correlation\nfunction in lattice simulation at small Euclidean time region. Both (i)\nperturbation calculation of 1+1 dimensional lattice Euclidean field theory\nmodel of fermions interacting with a contact interaction and (ii) Monte Carlo\nsimulation of a 1D exactly solvable quantum mechanics model are carried out to\ntest the proposed relation. In contrast to conventional two-step approach of\nextracting energy levels from temporal correlation function in lattice\nsimulation at large Euclidean time first and then applying L\\\"uscher formula to\nconvert energy levels into scattering phase shifts, we show that the difference\nof integrated correlation functions between interacting and noninteracting\ntrapped systems converges rapidly to infinite volume limit that is given in\nterms of scattering phase shifts at small Euclidean time region.",
        "positive": "Lattice Study of the Extent of the Conformal Window in Two-Color\n  Yang-Mills Theory: We perform a lattice calculation of the Schr\\\"odinger functional running\ncoupling in SU(2) Yang-Mills theory with six massless Wilson fermions in the\nfundamental representation. The aim of this work is to determine whether the\nabove theory has an infrared fixed point. Due to sensitivity of the $SF$\nrenormalized coupling to the tuning of the fermion bare mass we were unable to\nreliably extract the running coupling for stronger bare couplings."
    },
    {
        "anchor": "Spectral representation of lattice gluon and ghost propagators at zero\n  temperature: We consider the analytic continuation of Euclidean propagator data obtained\nfrom 4D simulations to Minkowski space. In order to perform this continuation,\nthe common approach is to first extract the K\\\"all\\'en-Lehmann spectral density\nof the field. Once this is known, it can be extended to Minkowski space to\nyield the Minkowski propagator. However, obtaining the K\\\"all\\'en-Lehmann\nspectral density from propagator data is a well known ill-posed numerical\nproblem. To regularize this problem we implement an appropriate version of\nTikhonov regularization supplemented with the Morozov discrepancy principle. We\nwill then apply this to various toy model data to demonstrate the conditions of\nvalidity for this method, and finally to zero temperature gluon and ghost\nlattice QCD data. We carefully explain how to deal with the IR singularity of\nthe massless ghost propagator. We also uncover the numerically different\nperformance when using two ---mathematically equivalent--- versions of the\nK\\\"all\\'en-Lehmann spectral integral.",
        "positive": "K* vector and tensor couplings from Nf = 2 tmQCD: The mass m_K* and vector coupling f_K* of the K*-meson, as well as the ratio\nof the tensor to vector couplings fT/fV|_K*, are computed in lattice QCD. Our\nsimulations are performed in a partially quenched setup, with two dynamical\n(sea) Wilson quark flavours, having a maximally twisted mass term. Valence\nquarks are either of the standard or the Osterwalder-Seiler maximally twisted\nvariety. Results obtained at three values of the lattice spacing are\nextrapolated to the continuum, giving m_K* = 981(33) MeV, f_K* = 240(18) MeV\nand fT(2 GeV)/fV|_K* = 0.704(41)."
    },
    {
        "anchor": "Remarks on abelian dominance: We used a renormalisation group based smoothing to address two questions\nrelated to abelian dominance. Smoothing drastically reduces short distance\nfluctuations but it preserves the long distance physical properties of the\nSU(2) configurations. This enabled us to extract the abelian heavy-quark\npotential from time-like Wilson loops on Polyakov gauge projected\nconfigurations. We obtained a very small string tension which is inconsistent\nwith the string tension extracted from Polyakov loop correlators. This shows\nthat the Polyakov gauge projected abelian configurations do not have a\nconsistent physical meaning. We also applied the smoothing on SU(2)\nconfigurations to test how sensitive abelian dominance in the maximal abelian\ngauge is to the short distance fluctuations. We found that on smoothed SU(2)\nconfigurations the abelian string tension was about 30% smaller than the SU(2)\nstring tension which was unaffected by smoothing. This suggests that the\napproximate abelian dominance found with the Wilson action is probably an\naccident and it has no fundamental physical relevance.",
        "positive": "Deep Inelastic Scattering in Improved Lattice QCD. I. The first moment\n  of structure functions: We present the complete 1-loop perturbative computation of the\nrenormalization constants and mixing coefficients of the operators that measure\nthe first moment of deep inelastic scattering structure functions, employing\nthe nearest neighbor improved lattice QCD action. The interest of using this\naction in Monte Carlo simulations lies in the fact that all terms which in the\ncontinuum limit are effectively of order $a$ ($a$ being the lattice spacing)\nhave been proven to be absent from on-shell hadronic lattice matrix elements.\n  Because of the complexity of the calculations, we have checked the analytical\nexpression of all Feynman diagrams using Schoonschip. To this end we have\ndeveloped a suitable code designed to automatically carry out all the necessary\nlattice algebraic manipulations, starting from the elementary building blocks\nof each diagram.\n  We have found discrepancies with some of the published numbers, but we are in\nagreement with the known results on the energy-momentum tensor."
    },
    {
        "anchor": "Numerical Analysis of the Quark Fraction of the Proton Spin: We report on a lattice QCD estimate of the quark spin fraction of the proton\nspin. The estimate is arrived at by means of a lattice QCD simulation of the\npolarized proton matrix element of the Adler-Bell-Jackiw anomaly. The\npreliminary result of the simulation is that this fraction is rather small.\nThis is in accord with the interpretation of the EMC experiment that the quark\nspins are responsible for very little, if any, of the proton spin. (Talk given\nat the Adriatico Research Conference on Polarization Dynamics in Nuclear and\nParticle Physics, Trieste, January, 1992) NOTE: This paper is available only in\npostscript form.",
        "positive": "Spectrum of the open QCD flux tube and its effective string description: I perform a high precision measurement of the static quark-antiquark\npotential in three-dimensional ${\\rm SU}(N)$ gauge theory with $N=2$ to 6. The\nresults are compared to the effective string theory for the QCD flux tube and I\nobtain continuum limit results for the string tension and the non-universal\nleading order boundary coefficient, including an extensive analysis of all\ntypes of systematic uncertainties. The magnitude of the boundary coefficient\ndecreases with increasing $N$, but remains non-vanishing in the large-$N$\nlimit. I also test for the presence of possible contributions from rigidity or\nmassive modes and compare the results for the string theory parameters to data\nfor the excited states."
    },
    {
        "anchor": "Extracting resonance parameters from lattice data: Monte Carlo simulations of the 4d O(4) model in the broken phase are\nperformed to determine the parameters of a resonance. The standard method for\nextracting them on the lattice is through L\\\"uscher's formula; recently a new\nmethod, based on the probability distribution concept, has been proposed. We\nstudy the application of these methods and compare them with Monte Carlo data.",
        "positive": "A High Statistics Lattice Calculation of Heavy-Light Meson Decay\n  Constants: We present a high statistics study of the D- and B-meson decay constants. The\nresults were obtained by using the Clover and Wilson lattice actions at two\ndifferent values of the lattice spacing $a$, corresponding to $\\beta=6.0$ and\n6.2. After a careful analysis of the systematic errors present in the\nextraction of the physical results, by assuming quite conservative\ndiscretization errors, we find $f_{D_s}=237 \\pm 16$ MeV, $f_{D} = 221 \\pm 17$\nMeV ($f_{D_s}/f_D=1.07(4)$), $f_{B_s} = 205 \\pm 35$ MeV, $f_{B} = 180 \\pm 32$\nMeV ($f_{B_s}/f_B=1.14(8)$), in good agreement with previous estimates."
    },
    {
        "anchor": "Simulating a CP-violating topological term in gauge theories: We present recent results on the theta-dependence of four-dimensional SU(N)\ngauge theories, where theta is the coefficient of the CP-violating topological\nterm in the Lagrangian. In particular, we study the scaling behavior of these\ntheories, by Monte Carlo simulations at imaginary theta. The numerical results\nprovide good evidence of scaling in the continuum limit. The imaginary theta\ndependence of the ground-state energy turns out to be well described by the\nfirst few terms of related expansions around theta=0, providing accurate\nestimates of the first few coefficients, up to O(theta^6).",
        "positive": "Fluctuations of conserved charges at finite temperature from lattice QCD: We present the full results of the Wuppertal-Budapest lattice QCD\ncollaboration on flavor diagonal and non-diagonal quark number susceptibilities\nwith 2+1 staggered quark flavors, in a temperature range between 125 and 400\nMeV. The light and strange quark masses are set to their physical values.\nLattices with Nt=6, 8, 10, 12, 16 are used. We perform a continuum\nextrapolation of all observables under study. A Symanzik improved gauge and a\nstout-link improved staggered fermion action is utilized. All results are\ncompared to the Hadron Resonance Gas model predictions: good agreement is found\nin the temperature region below the transition."
    },
    {
        "anchor": "Strongly Bound Dibaryon with Maximal Beauty Flavor from Lattice QCD: We report the first lattice QCD study of the heavy dibaryons in which all six\nquarks have the bottom (beauty) flavor. Performing a state-of-the-art lattice\nQCD calculation we find clear evidence for a deeply bound\n$\\Omega_{bbb}$-$\\Omega_{bbb}$ dibaryon in the $^1S_0$ channel, as a pole\nsingularity in the $S$-wave $\\Omega_{bbb}$-$\\Omega_{bbb}$ scattering amplitude\nwith a binding energy $-81(_{-16}^{+14})$ MeV. With such a deep binding,\nCoulomb repulsion serves only as a perturbation on the ground state wave\nfunction of the parameterized strong potential and may shift the strong binding\nonly by a few percent. Considering the scalar channel to be the most bound for\nsingle flavored dibaryons, we conclude this state is the heaviest possible most\ndeeply bound dibaryon in the visible universe.",
        "positive": "Improved action and Hamiltonian in finite volumes: We introduce a new Symanzik improved action by adding a 2x2 plaquette in such\na way that the Feynman rules in the covariant gauge simplify. We call this the\nsquare Symanzik action. Some comparisons with the continuum and the standard\nWilson action are made in intermediate volumes, where mass ratios are\naccurately known and the precise amount of improvement can be determined.\nRatios of the Lambda parameters will be presented, as well as partial results\nfor the one-loop improvement coefficients. We discuss some of the intricacies\nthat arise because of violations of unitarity at the scale of the cutoff. In\nparticular we show how a field redefinition in the zero-momentum effective\naction allows one to remove scaling violations linear in the lattice spacing."
    },
    {
        "anchor": "Continuum limit of the leading order HQET form factor in $B_s \\to\n  K\\ell\u03bd$ decays: We discuss the computation of form factors for semi-leptonic decays of $\\rm\nB$-, $\\rm B_s$- mesons in lattice QCD. Considering in particular the example of\nthe static $\\rm B_s$ form factors we demonstrate that after non-perturbative\nrenormalization the continuum limit can be taken with confidence. The resulting\nprecision is of interest for extractions of $V_{\\rm ub}$. The size of the\ncorrections of order $1/m_{\\rm b}$ is just estimated at present but it is\nexpected that their inclusion does not pose significant difficulties.",
        "positive": "One loop calculation in lattice QCD with domain-wall quarks: One loop corrections to the domain-wall quark propagator are calculated in\nmassless QCD. It is shown that no additative counter term to the current quark\nmass is generated in this theory, and the wave function renormalization factor\nof the massless quark is explicitly evaluated. We also show that an analysis\nwith a simple mean-field approximation can explain properties of the massless\nquark in numerical simulations of QCD with domain-wall quarks."
    },
    {
        "anchor": "Classically emulated digital quantum simulation for screening and\n  confinement in the Schwinger model with a topological term: We perform digital quantum simulation, using a classical simulator, to study\nscreening and confinement in a gauge theory with a topological term, focusing\non ($1+1$)-dimensional quantum electrodynamics (Schwinger model) with a theta\nterm. We compute the ground state energy in the presence of probe charges to\nestimate the potential between them, via adiabatic state preparation. We\ncompare our simulation results and analytical predictions for a finite volume,\nfinding good agreements. In particular our result in the massive case shows a\nlinear behavior for non-integer charges and a non-linear behavior for integer\ncharges, consistently with the expected confinement (screening) behavior for\nnon-integer (integer) charges.",
        "positive": "Neural Network Field Transformation and Its Application in HMC: We propose a generic construction of Lie group agnostic and gauge covariant\nneural networks, and introduce constraints to make the neural networks\ncontinuous differentiable and invertible. We combine such neural networks and\nbuild gauge field transformations that is suitable for Hybrid Monte Carlo\n(HMC). We use HMC to sample lattice gauge configurations in the transformed\nspace by the neural network parameterized gauge field transformations. Tested\nwith 2D U(1) pure gauge systems at a range of couplings and lattice sizes,\ncompared with direct HMC sampling, the neural network transformed HMC (NTHMC)\ngenerates Markov chains of gauge configurations with improved tunneling of\ntopological charges, while allowing less force calculations as the lattice\ncoupling increases."
    },
    {
        "anchor": "Precision Electromagnetic Structure of Octet Baryons in the Chiral\n  Regime: The electromagnetic properties of the baryon octet are calculated in quenched\nQCD on a 20^3 x 40 lattice with a lattice spacing of 0.128 fm using the\nfat-link irrelevant clover (FLIC) fermion action. FLIC fermions enable\nsimulations to be performed efficiently at quark masses as low as 300 MeV. By\ncombining FLIC fermions with an improved-conserved vector current, we ensure\nthat discretisation errors occur only at O(a^2) while maintaining current\nconservation. Magnetic moments and electric and magnetic radii are extracted\nfrom the electric and magnetic form factors for each individual quark sector.\n  From these, the corresponding baryon properties are constructed. Our results\nare compared extensively with the predictions of quenched chiral perturbation\ntheory. We detect substantial curvature and environment sensitivity of the\nquark contributions to electric charge radii and magnetic moments in the low\nquark mass region. Furthermore, our quenched QCD simulation results are in\naccord with the leading non-analytic behaviour of quenched chiral perturbation\ntheory, suggesting that the sum of higher-order terms makes only a small\ncontribution to chiral curvature.",
        "positive": "Lattice QCD Thermodynamics with Physical Quark Masses: Over the past few years new physics methods and algorithms as well as the\nlatest supercomputers have enabled the study of the QCD thermodynamic phase\ntransition using lattice gauge theory numerical simulations with unprecedented\ncontrol over systematic errors. This is largely a consequence of the ability to\nperform continuum extrapolations with physical quark masses. Here we review\nrecent progress in lattice QCD thermodynamics, focussing mainly on results that\nbenefit from the use of physical quark masses: the crossover temperature, the\nequation of state, and fluctuations of the quark number susceptibilities. In\naddition, we place a special emphasis on calculations that are directly\nrelevant to the study of relativistic heavy ion collisions at RHIC and the LHC."
    },
    {
        "anchor": "A note on Rome-Southampton Renormalization with Smeared Gauge Fields: We have calculated continuum limit step scaling functions of bilinear and\nfour-fermion operators renormalized in a Rome-Southampton scheme using various\nsmearing prescriptions for the gauge field. Also, for the first time, we have\ncalculated non-perturbative anomalous dimensions of operators renormalized in a\nRome-Southampton scheme. The effect of such smearing first enters connected\nfermionic correlation functions via radiative corrections. We use off-shell\nrenormalisation as a probe, and observe that the upper edge of the\nRome-Southampton window is reduced by link smearing. This can be interpreted as\narising due to the fermions decoupling from the high momentum gluons and we\nobserve that the running of operators with the scale at large lattice momenta\nshows enhanced lattice artefacts. We find that the effect is greater for HEX\nsmearing than for Stout smearing, but that in both cases additional care must\nbe taken when using off-shell renormalisation with smeared gauge fields\ncompared to thin link simulations.",
        "positive": "Excluded-volume effects for a hadron gas in Yang-Mills theory: When the multiplicities of particles produced in heavy-ion collisions are\nfitted to the hadron-resonance-gas model, excluded-volume effects play a\nsignificant role. In this work, we study the impact of such effects on the\nequation of state of pure Yang-Mills theory at low temperatures, comparing the\npredictions of the statistical model with lattice results. In particular, we\npresent a detailed analysis of the SU(2) and SU(3) Yang-Mills theories: we find\nthat, for both of them, the best fits to the equilibrium thermodynamic\nquantities are obtained when one assumes that the volume of different glueball\nstates is inversely proportional to their mass. The implications of these\nfindings for QCD are discussed."
    },
    {
        "anchor": "A new method to study lattice QCD at finite temperature and chemical\n  potential: Due to the sign problem, it is exponentially difficult to study QCD on the\nlattice at finite chemical potential. We propose a method --an overlap\nimproving multi-parameter reweighting technique-- to alleviate this problem. We\napply this method and give the phase diagram of four-flavor QCD obtained on\nlattices 4^4 and 4\\cdot6^3. Our results are based on {\\cal{O}}(10^3-10^4)\nconfigurations.",
        "positive": "Effects of Low vs. High Fermionic Modes on Hadron Mass Generation: A nonvanishing spectral density of the low-lying eigenmodes of the Dirac\noperator naturally is a signal for dynamical chiral symmetry breaking\n(D$\\chi$SB) via the Banks-Casher relation. The low-lying eigenmodes alone\nsaturate the pseudoscalar channel and the corresponding propagator successfully\nreproduces the pion mass. In this paper we investigate the effects on the mass\ngeneration of hadrons other than pions. The evolution of these masses upon\ninclusion of an increasing number of the low-lying eigenmodes is confronted\nwith the hadron mass spectrum upon removal of such eigenmodes."
    },
    {
        "anchor": "Short distance behaviour of the effective string: We study the Polyakov loop correlator in the (2+1) dimensional Z_2 gauge\nmodel. An algorithm that we have presented recently, allows us to reach high\nprecision results for a large range of distances and temperatures, giving us\nthe opportunity to test predictions of the effective Nambu-Goto string model.\nHere we focus on the regime of low temperatures and small distances. In\ncontrast to the high temperature, large distance regime, we find that our\nnumerical results are not well described by the two loop-prediction of the\nNambu-Goto model. In addition we compare our data with those for the SU(2) and\nSU(3) gauge models in (2+1) dimensions obtained by other authors. We generalize\nthe result of L\\\"uscher and Weisz for a boundary term in the interquark\npotential to the finite temperature case.",
        "positive": "$B$ and $B_c$ mesons with NRQCD and Clover actions: We present preliminary results from our study of the heavy-light spectrum and\ndecay constants. For the heavy quark, we use NRQCD at various masses around and\nabove the $b$ quark mass. For the first time, the heavy quark action and the\nheavy-light current consistently include corrections at second order in the\nnon-relativistic expansion, as well as the leading finite $a$ corrections. The\nlight quarks are simulated using a tadpole-improved Clover action at various\nmasses in the strange and $c$ quark region."
    },
    {
        "anchor": "The $A^2$ Asymmetry and Gluon Propagators in Lattice $SU(3)$\n  Gluodynamics at $T\\simeq T_c$: We study numerically the chromoelectric-chromomagnetic asymmetry of the\ndimension two $A^2$ gluon condensate as well as the infrared behavior of the\ngluon propagators at $T\\simeq T_c$ in the Landau-gauge $SU(3)$ lattice gauge\ntheory. We find that a very significant correlation of the real part of the\nPolyakov loop with the asymmetry as well as with the longitudinal propagator\nmakes it possible to determine the critical behavior of these quantities. We\nobtain the screening masses in different Polyakov-loop sectors and discuss the\ndependence of chromoelectric and chromomagnetic interactions of static color\ncharges and currents on the choice of the Polyakov-loop sector in the\ndeconfinement phase.",
        "positive": "Kl3 semileptonic form factor from 2+1 flavour lattice QCD: We present the first results for the Kl3 form factor from simulations with\n2+1 flavours of dynamical domain wall quarks. Combining our result, namely\nf_+(0)=0.964(5), with the latest experimental results for Kl3 decays leads to\n|V_{us}|=0.2249(14), reducing the uncertaintity in this important parameter.\nFor the O(p^6) term in the chiral expansion we obtain \\Delta f=-0.013(5)."
    },
    {
        "anchor": "Localized eigenmodes of the covariant lattice Laplacian: We study numerically the eigenmode spectrum of the covariant lattice\nLaplacian, in the fundamental SU(2) color group representation. It is found\nthat eigenmodes at the lower and upper ends of the spectrum are localized, and\nthat the localization volume scales. In contrast, the eigenmodes of the lattice\nFaddeev-Popov operator are all extended rather than localized (as required for\nconfinement) despite the similarity of the kinetic and Faddeev-Popov operators.",
        "positive": "The lowest-lying baryon masses in covariant SU(3)-flavor chiral\n  perturbation theory: We present an analysis of the baryon-octet and -decuplet masses using\ncovariant SU(3)-flavor chiral perturbation theory up to next-to-leading order.\nBesides the description of the physical masses we address the problem of the\nlattice QCD extrapolation. Using the PACS-CS collaboration data we show that a\ngood description of the lattice points can be achieved at next-to-leading order\nwith the covariant loop amplitudes and phenomenologically determined values for\nthe meson-baryon couplings. Moreover, the extrapolation to the physical point\nup to this order is found to be better than the linear one given at\nleading-order by the Gell-Mann-Okubo approach. The importance that a reliable\ncombination of lattice QCD and chiral perturbation theory may have for hadron\nphenomenology is emphasized with the prediction of the pion-baryon and\nstrange-baryon sigma terms."
    },
    {
        "anchor": "Finite density $\\mathbf{O(3)}$ non-linear sigma model and low energy\n  physics: We present lattice results for simulations of the $O(3)$ non-linear sigma\nmodel at finite chemical potential. The complex action problem is overcome by a\ndual variable representation of the model. We discuss two aspects of the theory\nat finite density: 1) The relation of the finite density data to scattering\nphases and wave-functions. 2) The phase-structure of the theory as a function\nof chemical potential and the possibility of a Kosterlitz-Thouless phase\ntransition.",
        "positive": "On the glueball spectrum in O(a)-improved lattice QCD: We calculate the light `glueball' mass spectrum in N_f=2 lattice QCD using a\nfermion action that is non-perturbatively O(a) improved. We work at lattice\nspacings a ~0.1 fm and with quark masses that range down to about half the\nstrange quark mass. We find the statistical errors to be moderate and under\ncontrol on relatively small ensembles. We compare our mass spectrum to that of\nquenched QCD at the same value of a. Whilst the tensor mass is the same (within\nerrors), the scalar mass is significantly smaller in the dynamical lattice\ntheory, by a factor of ~(0.84 +/- 0.03). We discuss what the observed m_q\ndependence of this suppression tells us about the dynamics of glueballs in QCD.\nWe also calculate the masses of flux tubes that wind around the spatial torus,\nand extract the string tension from these. As we decrease the quark mass we see\na small but growing vacuum expectation value for the corresponding flux tube\noperators. This provides clear evidence for `string breaking' and for the\n(expected) breaking of the associated gauge centre symmetry by sea quarks."
    },
    {
        "anchor": "Heavy semileptonics with a fully relativistic mixed action: The first phase of a heavy quark program based on twisted mass valence quarks\nhas been presented at last years's lattice conference. The CLS $N_f=2+1$\nensembles were used for their fine lattice spacing, while twisting the masses\nis expected to reduce discretisation errors even further and allow for a fully\nrelativistic calculation. We present our strategy and preliminary results on\nthree point functions, corresponding to $D\\to K$ and $D\\to\\pi$ semileptonic\ndecays. The form factors for $m_u=m_d=m_s$ quark masses obtained as a first\nstep are shown here to be at the percent level in statistical precision at\n$q^2=0$.",
        "positive": "Lorentz-covariant coordinate-space representation of the leading\n  hadronic contribution to the anomalous magnetic moment of the muon: We present a Lorentz-covariant, Euclidean coordinate-space expression for the\nhadronic vacuum polarisation, the Adler function and the leading hadronic\ncontribution to the anomalous magnetic moment of the muon. The representation\noffers a lot of flexibility for an implementation in lattice QCD. We expect it\nto be particularly helpful for the quark-line disconnected contributions."
    },
    {
        "anchor": "Wave Functions of the Proton Ground State in the Presence of a Uniform\n  Background Magnetic Field in Lattice QCD: We calculate the probability distributions of quarks in the ground state of\nthe proton, and how they are affected in the presence of a constant background\nmagnetic field. We focus on wave functions in the Landau and Coulomb gauges. We\nobserve the formation of a scalar u-d diquark clustering. The overall\ndistortion of the quark probability distribution under a very large magnetic\nfield, as demanded by the quantisation conditions on the field, is quite small.\nThe effect is to elongate the distributions along the external field axis while\nlocalizing the remainder of the distribution.",
        "positive": "Wolff-Type Embedding Algorithms for General Nonlinear $\u03c3$-Models: We study a class of Monte Carlo algorithms for the nonlinear $\\sigma$-model,\nbased on a Wolff-type embedding of Ising spins into the target manifold $M$. We\nargue heuristically that, at least for an asymptotically free model, such an\nalgorithm can have dynamic critical exponent $z \\ll 2$ only if the embedding is\nbased on an (involutive) isometry of $M$ whose fixed-point manifold has\ncodimension 1. Such an isometry exists only if the manifold is a discrete\nquotient of a product of spheres. Numerical simulations of the idealized\ncodimension-2 algorithm for the two-dimensional $O(4)$-symmetric $\\sigma$-model\nyield $z_{int,{\\cal M}^2} = 1.5 \\pm 0.5$ (subjective 68\\% confidence interval),\nin agreement with our heuristic argument."
    },
    {
        "anchor": "Two- and three-point functions in Landau gauge Yang-Mills-Higgs theory: Yang-Mills-Higgs theory offers a rich set of physics. In particular, in some\nregion of its parameter space it has QCD-like behavior, while in some other\nrange it is Higgs-like. Furthermore, for the choice of the gauge group SU(2)\nand an SU(2) Higgs flavor symmetry it is the Higgs sector of the standard\nmodel. Therefore, it is possible to study a plethora of phenomena within a\nsingle theory. Here the standard-model version is studied using lattice gauge\ntheory. Choosing non-aligned minimal Landau gauge, its propagators and\nthree-point vertices will be determined in both the QCD-like and Higgs-like\ndomains. This permits to test various proposals for how confinement works, as\nwell as how confinement and the Higgs effect differ. The correlations functions\nare found to exhibit a different behavior, depending on whether the lowest mass\nscalar flavor singlet is lighter than the vector triplet, heavier and stable,\nor unstable against decay into two vector triplets.",
        "positive": "Mean-Field Gauge Interactions in Five Dimensions I. The Torus: We consider the lattice regularization of a five dimensional SU(2) gauge\ntheory with periodic boundary conditions. We determine a consistent mean-field\nbackground and perform computations of various observables originating from\nfluctuations around this background. Our aim is to extract the properties of\nthe system in regimes of its phase diagram where it seems to be in a\ndimensionally reduced state. Within the mean-field theory we establish the\nexistence of a second order phase transition at finite value of the gauge\ncoupling for anisotropy parameter less than one, where there is evidence for\ndimensional reduction."
    },
    {
        "anchor": "The chiral and flavour projection of Dirac-Kahler fermions in the\n  geometric discretization: It is shown that an exact chiral symmetry can be described for Dirac-Kahler\nfermions using the two complexes of the geometric discretization. This\nprinciple is extended to describe exact flavour projection and it is shown that\nthis necessitates the introduction of a new operator and two new structures of\ncomplex. To describe simultaneous chiral and flavour projection, eight\ncomplexes are needed in all and it is shown that projection leaves a single\nflavour of chiral field on each.",
        "positive": "Clear correlation between monopoles and the chiral condensate in SU(3)\n  QCD: We study spontaneous chiral-symmetry breaking in SU(3) QCD in terms of the\ndual superconductor picture for quark confinement in the maximally Abelian (MA)\ngauge, using lattice QCD Monte Carlo simulations with four different lattices\nof $16^4$, $24^4$, $24^3\\times 6$ at $\\beta=6.0$ (i.e., the spacing $a \\simeq$\n0.1 fm), and $32^4$ at $\\beta=6.2$ (i.e., $a \\simeq$ 0.075 fm), at the quenched\nlevel. First, in the confinement phase, we find Abelian dominance and monopole\ndominance in the MA gauge for the chiral condensate in the chiral limit,using\nthe two different methods of i) the Banks-Casher relation with the Dirac\neigenvalue density and ii) finite quark-mass calculations with the quark\npropagator and its chiral extrapolation. In the high-temperature deconfined\nphase, the chiral restoration is observed also for the Abelian and the monopole\nsectors. Second, we investigate local correlation between the chiral condensate\nand monopoles, which topologically appear in the MA gauge. We find that the\nchiral condensate locally takes a quite large value near monopoles. As an\ninteresting possibility, the strong magnetic field around monopoles is\nresponsible to chiral symmetry breaking in QCD, similarly to the magnetic\ncatalysis."
    },
    {
        "anchor": "SU(4) pure-gauge phase structure and string tensions: We present numerical evidence that the SU(4) pure-gauge dynamics has a\nfinite-temperature first-order phase transition. For a $6\\times 20^3$ lattice,\nthis transition occurs at the inverse-square coupling of $8/g^2 \\sim 10.79$.\nBelow this and above the known bulk phase transition at $8/g^2 \\sim 10.2$ is a\nconfined phase in which we find two different string tensions, one between the\nfundamental 4 and $4^*$ representations and the other between the self-dual\ndiquark 6 representations. The ratio of these two is about 1.5. The correlation\nin the adjoint representation suggests no string forms between adjoint charges.",
        "positive": "Pion structure from twisted mass lattice QCD down to the physical pion\n  mass: We present an investigation of pion structure based on ETMC $N_f=2$ and\n$N_f=2+1+1$ twisted mass configurations at maximal twist. We compute the first\nmoment of the quark momentum fraction of the pion, $\\langle x \\rangle$ and the\nelectromagnetic form factor, $F_\\pi(Q^2)$. For the latter, momentum is injected\nusing twisted boundary conditions and the calculation is carried out directly\nat the physical pion mass. We find that our data are consistent with vector\nmeson dominance and experimental data in the region of small momentum transfer.\nFor $\\langle x \\rangle$, we find that our chirally and continuum extrapolated\nresult is compatible with its phenomenological value."
    },
    {
        "anchor": "Phase shifts in I=2 \u03c0\u03c0-scattering from two lattice approaches: We present a lattice QCD study of the phase shift of $I{=}2$ $\\pi\\pi$\nscattering on the basis of two different approaches: the standard finite volume\napproach by Luscher and the recently introduced HAL QCD potential method.\nQuenched QCD simulations are performed on lattices with extents\n$N_s{=}16,24,32,48$ and $N_t{=}128$ as well as lattice spacing\n$a{\\sim}0.115\\,\\mathrm{fm}$ and a pion mass of $m_\\pi{\\sim}940\\,\\mathrm{MeV}$.\nThe phase shift and the scattering length are calculated in these two methods.\nIn the potential method, the error is dominated by the systematic uncertainty\nassociated with the violation of rotational symmetry due to finite lattice\nspacing. In Luscher's approach, such systematic uncertainty is difficult to be\nevaluated and thus is not included in this work. A systematic uncertainty\nattributed to the quenched approximation, however, is not evaluated in both\nmethods. In case of the potential method, the phase shift can be calculated for\narbitrary energies below the inelastic threshold. The energy dependence of the\nphase shift is also obtained from Luscher's method using different volumes\nand/or nonrest-frame extension of it. The results are found to agree well with\nthe potential method.",
        "positive": "Including electromagnetism in $K\\to\u03c0\u03c0$ decay calculations: Because of the small size of the ratio A_2/A_0 of the I=2 to I=0 K -> pipi\ndecay amplitudes (the Delta I=1/2 rule) the effects of electromagnetism on A_2\nmay be a factor of 20 larger than given by a naive O(alpha) estimate. Thus, if\nfuture calculations of A_2 and epsilon'/epsilon are to achieve 10% accuracy,\nthese effects need to be included. Here we present the first steps toward\nincluding electromagnetism in a calculation of the standard model K -> pipi\ndecay amplitudes using lattice QCD."
    },
    {
        "anchor": "Phase structure of two-color QCD at real and imaginary chemical\n  potentials; lattice simulations and model analyses: We investigate the phase structure of two-color QCD at both real and\nimaginary chemical potentials mu, performing lattice simulations and analyzing\nthe data with the Polyakov-loop extended Nambu--Jona-Lasinio (PNJL) model.\nLattice QCD simulations are done on an 8^3 times 4 lattice with the\nclover-improved two-flavor Wilson fermion action and the renormalization-group\nimproved Iwasaki gauge action. We test the analytic continuation of physical\nquantities from imaginary mu to real mu by comparing lattice QCD results\ncalculated at real mu with the result of analytic function the coefficients of\nwhich are determined from lattice QCD results at imaginary mu. We also test the\nvalidity of the PNJL model by comparing model results with lattice QCD ones.\nThe PNJL model is good in the deconfinement region, but less accurate in the\ntransition and confinement regions. This problem is improved by introducing the\nbaryon degree of freedom to the model. It is also found that the vector-type\nfour-quark interaction is necessary to explain lattice data on the quark number\ndensity.",
        "positive": "Nuclear physics from lattice simulations: We review recent lattice QCD activities with emphasis on the impact on\nnuclear physics. In particular, the progress toward the determination of\nnuclear and baryonic forces (potentials) using Nambu-Bethe-Salpeter (NBS) wave\nfunctions is presented. We discuss major challenges for multi-baryon systems on\nthe lattice: (i) signal to noise issue and (ii) computational cost issue. We\nargue that the former issue can be avoided by extracting energy-independent\n(non-local) potentials from time-dependent NBS wave functions without relying\non the ground state saturation, and the latter cost is drastically reduced by\ndeveloping a novel \"unified contraction algorithm.\" The lattice QCD results for\nnuclear forces, hyperon forces and three-nucleon forces are presented, and\nphysical insights are discussed. Comparison to results from the traditional\nLuescher's method is given, and open issues to be resolved are addressed as\nwell."
    },
    {
        "anchor": "Heavy Flavours in Quark-Gluon Plasma: Recent progresses in lattice studies of heavy quark and quarkonium at\nnon-zero temperature are discussed. Formulating a tail of spectral functions as\na transport coefficient allows lattice determination of momentum diffusion\ncoefficient ($\\kappa$) for charm quark in the heavy quark mass limit and\nlattice determination of heavy quark/heavy anti-quark chemical equilibration\nrate in NRQCD. Quenched lattice study on a large volume gives $\\kappa/T^3 = 1.8\n\\cdots 3.4$ in the continuum limit. A recent study with $N_f = 2+1$\nconfigurations estimates the charmonium chemical equilibration rate\n$\\Gamma_{\\rm chem}$. At $T = 400$ MeV with $M \\sim 1.5$ GeV, $\\Gamma_{\\rm\nchem}^{-1} \\sim 150$ fm/c. Earlier results from the two studies (with different\nlattice setups and with different Bayesian priors) which calculate bottomonium\ncorrelators using NRQCD and employ Bayesian method to calculate spectral\nfunctions are summarized: $\\Upsilon (1S)$ survives upto $T \\sim 1.9 T_c$ and\nexcited states of $\\Upsilon$ are sequentially suppressed. The spectral\nfunctions of $\\chi_{b1}$ channel shows a Bayesian prior dependence of its\nthermal behavior: the $\\chi_{b1}$ spectral function with MEM prior shows\nmelting above $T_c$ but that with a new Bayesian prior hints survival of\n$\\chi_{b1}$ upto $\\sim 1.6 T_c$. Preliminary results from the efforts to\nunderstand the difference in the behavior of $\\chi_{b1}$ spectral function is\ngiven.",
        "positive": "Quark masses using domain wall fermions: Due to the attractive features that domain wall fermions possess with respect\nto chiral symmetry, we continue our investigation of the light quark masses\nwith this discretization. Achieving reliable results, especially for $(m_u +\nm_d)/2$, requires strict control of systematic uncertainties. Our present\nresults were obtained on a quenched $\\beta =6.0$ lattice with spatial volume\n$\\approx (1.5~{\\rm fm})^3$. Consequently we remark on effects of finite volume\nas well as finite extent in the fictitious fifth dimension. We compute the\nrenormalization factors nonperturbatively and compare to the one--loop\nperturbative result."
    },
    {
        "anchor": "Light-cone distribution amplitudes of the baryon octet: We present results of the first ab initio lattice QCD calculation of the\nnormalization constants and first moments of the leading twist distribution\namplitudes of the full baryon octet, corresponding to the small transverse\ndistance limit of the associated S-wave light-cone wave functions. The P-wave\n(higher twist) normalization constants are evaluated as well. The calculation\nis done using $N_f=2+1$ flavors of dynamical (clover) fermions on lattices of\ndifferent volumes and pion masses down to 222 MeV. Significant SU(3) flavor\nsymmetry violation effects in the shape of the distribution amplitudes are\nobserved.",
        "positive": "Distribution of Stress Tensor around Static Quark--Anti-Quark from\n  Yang-Mills Gradient Flow: The spatial distribution of the stress tensor around the quark--anti-quark\n($Q\\bar{Q}$) pair in SU(3) lattice gauge theory is studied. The Yang-Mills\ngradient flow plays a crucial role to make the stress tensor well-defined and\nderivable from the numerical simulations on the lattice. The resultant stress\ntensor with a decomposition into local principal axes shows, for the first\ntime, the detailed structure of the flux tube along the longitudinal and\ntransverse directions in a gauge invariant manner. The linear confining\nbehavior of the $Q\\bar{Q}$ potential at long distances is derived directly from\nthe integral of the local stress tensor."
    },
    {
        "anchor": "Discrete Symmetry Enhancement in Nonabelian Models and the Existence of\n  Asymptotic Freedom: We study the universality between a discrete spin model with icosahedral\nsymmetry and the O(3) model in two dimensions. For this purpose we study\nnumerically the renormalized two-point functions of the spin field and the four\npoint coupling constant. We find that those quantities seem to have the same\ncontinuum limits in the two models. This has far reaching consequences, because\nthe icosahedron model is not asymptotically free in the sense that the coupling\nconstant proposed by L\"uscher, Weisz and Wolff [1] does not approach zero in\nthe short distance limit. By universality this then also applies to the O(3)\nmodel, contrary to the predictions of perturbation theory.",
        "positive": "Scaling test of quenched Wilson twisted mass QCD at maximal twist: We present the results of an extended scaling test of quenched Wilson twisted\nmass QCD. We fix the twist angle by using two definitions of the critical mass,\nthe first obtained by requiring the vanishing of the pseudoscalar meson mass\nm_PS for standard Wilson fermions and the second by requiring restoration of\nparity at non-zero value of the twisted mass mu and subsequently extrapolating\nto mu=0. Depending on the choice of the critical mass we simulate at values of\nbeta in [5.7,6.45], for a range of pseudoscalar meson masses 250 MeV < m_PS < 1\nGeV and we perform the continuum limit for the pseudoscalar meson decay\nconstant f_PS and various hadron masses (vector meson m_V, baryon octet m_oct\nand baryon decuplet m_dec) at fixed value of r_0 m_PS. For both definitions of\nthe critical mass, lattice artifacts are consistent with O(a) improvement.\nHowever, with the second definition, large O(a^2) discretization errors present\nat small quark mass with the first definition are strongly suppressed. The\nresults in the continuum limit are in very good agreement with those from the\nAlpha and CP-PACS Collaborations."
    },
    {
        "anchor": "The Sequential Empirical Bayes Method: An Adaptive Constrained-Curve\n  Fitting Algorithm for Lattice QCD: We introduce the ``Sequential Empirical Bayes Method'', an adaptive\nconstrained-curve fitting procedure for extracting reliable priors. These are\nthen used in standard augmented-$\\chi^2$ fits on separate data. This better\nstabilizes fits to lattice QCD overlap-fermion data at very low quark mass\nwhere {\\it a priori} values are not otherwise known. Lessons learned (including\ncaveats limiting the scope of the method) from studying artificial data are\npresented. As an illustration, from local-local two-point correlation\nfunctions, we obtain masses and spectral weights for ground and first-excited\nstates of the pion, give preliminary fits for the $a_0$ where ghost states (a\nquenched artifact) must be dealt with, and elaborate on the details of fits of\nthe Roper resonance and $S_{11}(N^{1/2-})$ previously presented elsewhere. The\ndata are from overlap fermions on a quenched $16^3\\times 28$ lattice with\nspatial size $La=3.2 {\\rm fm}$ and pion mass as low as $\\sim 180 {\\rm MeV}$.",
        "positive": "Mass-improvement of the vector current in three-flavor QCD: We determine two improvement coefficients which are relevant to cancel\nmass-dependent cutoff effects in correlation functions with operator insertions\nof the non-singlet local QCD vector current. This determination is based on\ndegenerate three-flavor QCD simulations of non-perturbatively O(a) improved\nWilson fermions with tree-level improved gauge action. Employing a very robust\nstrategy that has been pioneered in the quenched approximation leads to an\naccurate estimate of a counterterm cancelling dynamical quark cutoff effects\nlinear in the trace of the quark mass matrix. To our knowledge this is the\nfirst time that such an effect has been determined systematically with large\nsignificance."
    },
    {
        "anchor": "Multigrid Methods for the Computation of Propagators in Gauge Fields: NOTE: this is a shortened version of the abstract of the paper.\n  Multigrid methods for propagators in gauge fields are investigated.\n  Gauge fields are incorporated in algorithms in a covariant way. This avoids\nthe necessity for gauge fixing in computations of propagators.\n  The kernel $C$ of the restriction operator which averages from one grid to\nthe next coarser grid is defined by projection on the ground- state of a local\nHamiltonian. The idea behind this definition is that the appropriate notion of\nsmoothness depends on the dynamics. The ground-state projection choice of $C$\nis usable in arbitrary space-time dimension $d$ and for arbitrary gauge group.\nWe discuss proper averaging operations for bosons and for staggered fermions.\nThe averaging kernels $C$ can be used not only in deterministic multigrid\ncomputations, but also in multigrid Monte Carlo simulations, and for the\ndefinition of block spins and blocked gauge fields in Monte Carlo\nrenormalization group studies of gauge theories. Actual numerical computations\nof kernels and propagators are performed in compact four-dimensional $SU(2)$\ngauge fields. A central result of the present work is that {\\em the multigrid\nmethod works in arbitrarily disordered gauge fields, in principle\\/}.",
        "positive": "A Fermion Doublet With Chiral Gauge Interaction On A Lattice: We present a new staggered discretization of the Dirac operator. Doubling\ngives only a doublet of Dirac fermions which we propose to interpret as a\nphysical (lepton or quark) doublet. If coupled with gauge fields, an\n$(1+\\gamma^5)$ chiral interaction appears in a natural way. We define a\ngeneralization for curved background which does not require tetrad variables.\nThe approach suggests a natural explanation for the three fermion families."
    },
    {
        "anchor": "The B-meson mass splitting from non-perturbative quenched lattice QCD: We perform the non-perturbative (quenched) renormalization of the\nchromo-magnetic operator in Heavy Quark Effective Theory and its three-loop\nmatching to QCD. At order 1/m of the expansion, the operator is responsible for\nthe mass splitting between the pseudoscalar and vector B-mesons. These new\ncomputed factors are affected by an uncertainty negligible in comparison to the\nknown bare matrix element of the operator between B-states. Furthermore, they\npush the quenched determination of the spin splitting for the Bs-meson much\ncloser to its experimental value than the previous perturbatively renormalized\ncomputations. The renormalization factor for three commonly used heavy quark\nactions and the Wilson gauge action and useful parametrizations of the matching\ncoefficient are provided.",
        "positive": "Meson and baryon masses with low mode averaging: We describe and test a method known in the literature as low mode averaging\nto improve Euclidean two-point functions in lattice QCD using the low-lying\neigenmodes of the Wilson-Dirac operator D. The contribution from the low modes\nis averaged over all positions of the quark sources while the contribution from\nhigh modes is calculated in the traditional way using one source point per\nlattice. We apply this method to different baryon and meson two-point functions\nand we compare the improvements using the eigenmodes of the non-hermitian\noperator D and the eigenmodes of the hermitian operator Q=gamma5 D. The\nconvergence strongly depends on the parity of the states."
    },
    {
        "anchor": "Spatial Correlation of the Topological Charge in Pure SU(3) Gauge Theory\n  and in QCD: We study the spatial correlator of the topological charge density operator in\npure SU(3) gauge theory and in two flavor QCD. We show that the data for\ndistances up to about 1 fm is consistent with a vacuum consisting of individual\ninstantons and closely bound pairs. The percentage of paired objects is twice\nas large on the dynamical configurations than on the pure gauge ones, implying\nincreased molecule formations due to fermionic interactions.",
        "positive": "Low energy physics from the QCD Schr\u00f6dinger functional: We review recent work by the ALPHA and UKQCD Collaborations where masses and\nmatrix elements were computed in lattice QCD using Schr\\\"odinger functional\nboundary conditions and where the strange quark mass was determined in the\nquenched approximation. We emphasize the general concepts and our strategy for\nthe computation of quark masses."
    },
    {
        "anchor": "A strategy to study the role of the charm quark in explaining the\n  Delta{I}=1/2 rule: We present a strategy designed to separate several possible origins of the\nwell-known enhancement of the Delta{I}=1/2 amplitude in non-leptonic kaon\ndecays. In particular, we seek to disentangle the contribution of physics at\nthe typical QCD scale (soft-gluon exchange) from the effects at the scale of\nthe charm quark mass. This is achieved by considering QCD with an unphysically\nlight charm quark, so that the theory possesses an approximate SU(4)_L x\nSU(4)_R chiral symmetry. By computing the relevant operator matrix elements and\nmonitoring their values as the charm quark mass departs from the\nSU(4)-symmetric situation, the role of the charm quark can be assessed. We\nstudy the influence of the charm quark mass in Chiral Perturbation Theory.\nFirst results from lattice simulations in the SU(4)-symmetric limit are also\ndiscussed.",
        "positive": "Precision Lattice Calculation of D and Ds decay constants: We present a determination of the decay constants of the $D$ and $D_s$ mesons\nfrom lattice QCD, each with a total error of about 2%, approximately a factor\nof three better than previous calculations. We have been able to achieve this\nthrough the use of a highly improved discretization of QCD for charm quarks,\ncoupled to gauge configurations generated by the MILC collaboration that\ninclude the full effect of sea u, d, and s quarks. We have results for a range\nof u/d masses down to m_s/5 and three values of the lattice spacing, which\nallow us to perform accurate continuum and chiral extrapolations. We fix the\ncharm quark mass to give the experimental value of the \\eta_c mass, and then a\nstringent test of our approach is the fact that we obtain correct (and\naccurate) values for the mass of the D and D_s mesons. We compare f_D and\nf_{D_s} with f_K and f_\\pi, and using experiment determine corresponding CKM\nelements with good precision."
    },
    {
        "anchor": "Numerical Study of the Two Color Attoworld: We consider QCD at very low temperatures and non-zero quark chemical\npotential from lattice Monte Carlo simulations of the two-color theory in a\nvery small spatial volume (the attoscale). In this regime the quark number\nrises in discrete levels in qualitative agreement with what is found\nanalytically at one loop on S3xS1 with radius R_S3 << 1/{\\Lambda}_QCD. The\ndetailed level degeneracy, however, cannot be accounted for using weak coupling\narguments. At each rise in the quark number there is a corresponding spike in\nthe Polyakov line, also in agreement with the perturbative results. In addition\nthe quark number susceptibility shows a similar behaviour to the Polyakov line\nand appears to be a good indicator of a confinement-deconfinement type of\ntransition.",
        "positive": "New possibilities for QCD at finite density: I review the growing theoretical indications that at high densities color\nSU(3) gauge symmetry is spontaneously broken by the formation of a quark pair\ncondensate. This leads to a rich phase structure for QCD as a function of\ntemperature and chemical potential.\n  I also discuss the prospects for lattice QCD calculations at finite density,\nincluding the Glasgow algorithm and imaginary chemical potential."
    },
    {
        "anchor": "Mixed Action Effective Field Theory: an Addendum: We correct a mistake in the literature regarding the additive lattice spacing\ncorrections to the mixed valence-sea meson mass and discuss the consequences\nfor mixed action extrapolation formulae.",
        "positive": "Some universal features of the effective string picture of pure gauge\n  theories: The effective string describing the large distance behaviour of the quark\nsources of gauge field theories in the confining phase in D=3 or D=4 space-time\ndimensions can be formulated, in the infrared limit, as a suitable 2D conformal\nfield theory on surfaces with quark loops as boundaries. Recent results on\nself-avoiding random surfaces allow to fix almost uniquely such a conformal\ntheory. As a consequence, some universal relationships among the string tension\n, the thickness of the colour flux tube, the deconfinement temperature and a\nlower bound of the glueball mass spectrum are found. The general agreement with\nthe data extracted from recent lattice simulations with different gauge groups\nis rather impressive.(Talk held by F.Gliozzi at Lattice'92 , Amsterdam)"
    },
    {
        "anchor": "Worldsheet Formulation for Lattice Staggered Fermions: The worldsheet formulation is introduced for lattice gauge theories with\ndynamical fermions. The partition function of lattice compact QED with\nstaggered fermions is expressed as a sum over surfaces with border on\nself-avoiding fermionic paths. The surfaces correspond to the world sheets of\nloop-like pure electric flux excitations and meson-like configurations (open\nelectric flux tubes carrying matter fields at their ends). The proposed\nformulation does not have the problem of the additional doubling of the fermion\nspecies due to the discretization of time. The gauge non-redundancy and the\ngeometric transparency are two appealing features of this description. From the\ncomputational point of view, the partition function involves fewer degrees of\nfreedom than the Kogut-Susskind formulation and offers an alternative and more\neconomic framework to perform numerical computations with dynamical fermions.",
        "positive": "Asymptotic behavior of the ghost propagator in SU3 lattice gauge theory: We study the asymptotic behavior of the ghost propagator in the quenched\nSU(3) lattice gauge theory with Wilson action. The study is performed on\nlattices with a physical volume fixed around 1.6 fm and different lattice\nspacings: 0.100 fm, 0.070 fm and 0.055 fm. We implement an efficient algorithm\nfor computing the Faddeev-Popov operator on the lattice. We are able to\nextrapolate the lattice data for the ghost propagator towards the continuum and\nto show that the extrapolated data on each lattice can be described up to\nfour-loop perturbation theory from 2.0 GeV to 6.0 GeV. The three-loop values\nare consistent with those extracted from previous perturbative studies of the\ngluon propagator. However the effective $\\Lambda_{\\ms}$ scale which reproduces\nthe data does depend strongly upon the order of perturbation theory and on the\nrenormalization scheme used in the parametrization. We show how the truncation\nof the perturbative series can account for the magnitude of the dependency in\nthis energy range. The contribution of non-perturbative corrections will be\ndiscussed elsewhere."
    },
    {
        "anchor": "Renormalization of minimally doubled fermions: We investigate the renormalization properties of minimally doubled fermions,\nat one loop in perturbation theory. Our study is based on the two particular\nrealizations of Borici-Creutz and Karsten-Wilczek. A common feature of both\nformulations is the breaking of hyper-cubic symmetry, which requires that the\nlattice actions are supplemented by suitable counterterms. We show that three\ncounterterms are required in each case and determine their coefficients to one\nloop in perturbation theory. For both actions we compute the vacuum\npolarization of the gluon. It is shown that no power divergences appear and\nthat all contributions which arise from the breaking of Lorentz symmetry are\ncancelled by the counterterms. We also derive the conserved vector and\naxial-vector currents for Karsten-Wilczek fermions. Like in the case of the\npreviously studied Borici-Creutz action, one obtains simple expressions,\ninvolving only nearest-neighbour sites. We suggest methods how to fix the\ncoefficients of the counterterms non-perturbatively and discuss the\nimplications of our findings for practical simulations.",
        "positive": "Gluon field distribution in baryons: Methods for revealing the distribution of gluon fields within the three-quark\nstatic-baryon potential are presented. In particular, we outline methods for\nstudying the sensitivity of the source on the emerging vacuum response for the\nthree-quark system. At the same time, we explore the possibility of revealing\ngluon-field distributions in three-quark systems in QCD without the use of\ngauge-dependent smoothing techniques. Renderings of flux tubes from a\npreliminary high-statistics study on a 12^3 X 24 lattice are presented."
    },
    {
        "anchor": "The Well-Defined Phase of Simplicial Quantum Gravity in Four Dimensions: We analyze simplicial quantum gravity in four dimensions using the Regge\napproach. The existence of an entropy dominated phase with small negative\ncurvature is investigated in detail. It turns out that observables of the\nsystem possess finite expectation values although the Einstein-Hilbert action\nis unbounded. This well-defined phase is found to be stable for a one-parameter\nfamily of measures. A preliminary study indicates that the influence of the\nlattice size on the average curvature is small. We compare our results with\nthose obtained by dynamical triangulation and find qualitative correspondence.",
        "positive": "The SU(2)-Higgs model on asymmetric lattices: We calculate the ${\\cal O}(g^2,\\lambda)$ corrections to the coupling\nanisotropies of the SU(2)-Higgs model on lattices with asymmetric lattice\nspacings. These corrections are obtained by a one-loop calculation requiring\nthe rotational invariance of the gauge- and Higgs-boson propagators in the\ncontinuum limit."
    },
    {
        "anchor": "Isovector charges of the nucleon from 2+1-flavor QCD with clover\n  fermions: We present high-statistics estimates of the isovector charges of the nucleon\nfrom four 2+1-flavor ensembles generated using Wilson-clover fermions with\nstout smearing and tree-level tadpole improved Symanzik gauge action at lattice\nspacings $a=0.114$ and $0.080$ fm and with $M_\\pi \\approx 315$ and 200 MeV. The\ntruncated solver method with bias correction and the coherent source sequential\npropagator construction are used to cost-effectively achieve $O(10^5)$\nmeasurements on each ensemble. Using these data, the analysis of two-point\ncorrelation functions is extended to include four states in the fits and of\nthree-point functions to three states. Control over excited-state contamination\nin the calculation of the nucleon mass, the mass gaps between excited states,\nand in the matrix elements is demonstrated by the consistency of estimates\nusing this multistate analysis of the spectral decomposition of the correlation\nfunctions and from simulations of the three-point functions at multiple values\nof the source-sink separation. The results for all three charges, $g_A$, $g_S$\nand $g_T$, are in good agreement with calculations done using the\nclover-on-HISQ lattice formulation with similar values of the lattice\nparameters.",
        "positive": "A non-perturbative determination of $b_{\\rm g}$: Close to the continuum limit, lattice QCD with mass-degenerate Wilson quarks\ncan be described by Symanzik's effective continuum action, which contains the\ndimension 5 operator, $m\\,{\\rm tr}(F_{\\mu\\nu}F_{\\mu\\nu})$. Its effect can be\neliminated by an O($am_{\\rm q}$) rescaling of the bare lattice coupling\nconstant. Until recently, the corresponding improvement coefficient, $b_{\\rm\ng}$, was only known perturbatively to 1-loop order and an estimate of the\nremaining uncertainty is the dominant systematic error in the ALPHA\ncollaboration's recent determination of $\\alpha_s(m_Z)$ with the decoupling\nmethod. To remove this error we have determined $b_{\\rm g}$ non-perturbatively\nfor the corresponding parameter range. We here briefly review improvement\nconditions for $b_{\\rm g}$, perform a perturbative test and report on our\nnon-perturbative results for $b_{\\rm g}$."
    },
    {
        "anchor": "Finite-volume scattering on the left-hand cut: The two-particle finite-volume scattering formalism derived by L\\\"uscher and\ngeneralized in many subsequent works does not hold for energies far enough\nbelow the two-particle threshold to reach the nearest left-hand cut. The\nbreakdown of the formalism is signaled by the fact that a real scattering\namplitude is predicted in a regime where it should be complex. In this work, we\naddress this limitation by deriving an extended formalism that includes the\nnearest branch cut, arising from single particle exchange. We focus on\ntwo-nucleon ($NN \\to NN$) scattering, for which the cut arises from pion\nexchange, but give expressions for any system with a single channel of\nidentical particles. The new result takes the form of a modified quantization\ncondition that can be used to constrain an intermediate K-matrix in which the\ncut is removed. In a second step, integral equations, also derived in this\nwork, must be used to convert the K-matrix to the physical scattering\namplitude. We also show how the new formalism reduces to the standard approach\nwhen the $N \\to N \\pi$ coupling is set to zero.",
        "positive": "Scale setting, sigma terms and the Feynman-Hellman theorem: The authors recently presented new values for the octet baryon sigma terms.\nThese were extracted using the Feynman-Hellman theorem from a chiral\nperturbation theory fit to octet baryon mass data from the PACS-CS\ncollaboration. Of particular interest is the precise determination of the\nstrangeness sigma term $\\sigma_s = 21 \\pm 6$ MeV. In this work, we elaborate on\nthe critical effect which the choice of scale setting has on this value. We\ndiscuss the prospect that the comparison of direct and 'spectrum'\ndeterminations of the sigma terms from the lattice can provide insight not only\ninto scale setting on the lattice, but into QCD itself."
    },
    {
        "anchor": "Renormalization constants of quark bilinear operators in QCD with\n  dynamical up, down, strange and charm quarks: We present preliminary results of a calculation of the QCD renormalization\nconstants (RCs) for quark bilinear operators, evaluated non-perturbatively on\nthe lattice in the RI'-MOM scheme. The calculation is performed by using\ndedicated ensembles with $N_f=4$ degenerate dynamical twisted mass (clover)\nfermions and the Iwasaki gauge action. A detailed analysis is reported, with\nemphasis on the control or subtraction of the hadronic contaminations occurring\nin the lattice estimators of RCs and a check of proper scaling with $a^2$ of\nthe final results. Such a careful study of systematic errors is the counterpart\nof the high statistical precision reached by current calculations of RCs in the\nRI'-MOM scheme and is important in order to quote accurate results in\nphenomenological applications, such as the computation of quark masses.",
        "positive": "On the Phase Diagram of QCD with Small Isospin Chemical Potential: The regime of small isospin chemical potential in QCD is investigated. Using\nthe phase quenched partition function in the $\\epsilon$-regime an expression\nfor the chiral condensate is given, which is studied in the temperature isospin\nchemical potential plane. Lines of constant values of the condensate are shown\nand it is estimated how the critical temperature varies as a function of the\nisospin chemical potential. Finally, the dependency of the fermion sign problem\non the chemical potential and temperature is examined."
    },
    {
        "anchor": "Imaginary Chemical Potential Approach for the Pseudo-Critical Line in\n  the QCD Phase Diagram with Clover-Improved Wilson Fermions: The QCD phase diagram is studied in the lattice QCD simulation with the\nimaginary chemical potential approach. We employ a clover-improved Wilson\nfermion action of two-flavors and a renormalization-group improved gauge\naction, and perform the simulation at an intermediate quark mass on a\n$8^3\\times 4$ lattice. The QCD phase diagram in the imaginary chemical\npotential $\\mu_I$ region is investigated by performing the simulation for more\nthan 150 points on the $(\\beta,\\mu_I)$ plane. We find that the Roberge-Weiss\nphase transition at $\\mu_I/T=\\pi/3$ is first order and its endpoint is second\norder, which are identified by the phase of the Polyakov loop. We determine the\npseudo-critical line from the susceptibility of the Polyakov loop modulus. We\nfind a clear deviation from a linear dependence of the pseudo-critical line on\n$\\mu_I^2$.",
        "positive": "Deep Learning Hamiltonian Monte Carlo: We generalize the Hamiltonian Monte Carlo algorithm with a stack of neural\nnetwork layers and evaluate its ability to sample from different topologies in\na two dimensional lattice gauge theory. We demonstrate that our model is able\nto successfully mix between modes of different topologies, significantly\nreducing the computational cost required to generated independent gauge field\nconfigurations. Our implementation is available at\nhttps://github.com/saforem2/l2hmc-qcd ."
    },
    {
        "anchor": "Thermodynamics using p4-improved staggered fermion action on QCDOC: We present an exploratory study of the thermodynamics of $N_f=3$ QCD with an\nimproved staggered fermions using the QCDOC supercomputer. We use a p4 action\nwith MILC-style smeared links (Fat 7). Some details of the implementation of\nthe p4 action on QCDOC are discussed and performance benchmarks are given. We\nshow preliminary results for the quark mass dependence of the pseudo-critical\ntemperature $T_c$ from several lattice volumes . We also make a comparison\nbetween p4fat7 and the old p4 action.",
        "positive": "Triple-gluon and quark-gluon vertex from lattice QCD in Landau gauge: We report on preliminary results for the triple-gluon and the quark-gluon\nvertex in Landau gauge. Our results are based on two-flavor and quenched\nlattice QCD calculations for different quark masses, lattice spacings and\nvolumes. We discuss the momentum dependence of some of the vertices's form\nfactors and the deviations from the tree-level form."
    },
    {
        "anchor": "Analytical study of low temperature phase of 3D LGT in the plaquette\n  formulation: We develop an analytical approach for non-abelian gauge models within the\nplaquette representation where the plaquette matrices play the role of the\nfundamental degrees of freedom. We start from the original Batrouni formulation\nand show how it can be modified in such a way that each non-abelian Bianchi\nidentity contains two connectors instead of four. Using this representation we\nconstruct the low-temperature expansion for U(1) and SU(N) models on a finite\nlattice and discuss its uniformity in the volume. Next, we derive a dual\nrepresentation for the 't Hooft loop in the SU(2) model and describe monopoles\nin the maximal axial gauge.",
        "positive": "Determination of the Strong Coupling Constant by the ALPHA Collaboration: A high precision determination of the strong coupling constant in the MS-bar\nscheme at the Z-mass scale, using low energy quantities, namely pion/kaon decay\nconstants and masses, as experimental input is presented. The computation\nemploys two different massless finite volume renormalization schemes to\nnon-perturbatively trace the scale dependence of the respective running\ncouplings from a scale of about 200 MeV to 100 GeV. At the largest energies\nperturbation theory is reliable. At high energies the Schroedinger-Functional\nscheme is used, while the running at low and intermediate energies is computed\nin a novel renormalization scheme based on an improved gradient flow. Large\nvolume Nf=2+1 QCD simulations by CLS are used to set the overall scale. The\nresult is compared to world averages by FLAG and the PDG."
    },
    {
        "anchor": "A quantitative study of the Kosterlitz-Thouless phase transition in a\n  system of two-dimensional plane rotators ( XY model ) by high temperature\n  expansions through $\u03b2^{20}$: High temperature series expansions of the spin-spin correlation function for\nthe plane rotator (or XY) model on the square lattice are extended by three\nterms through order $\\beta^{20}$. Tables of the expansion coefficients are\nreported for the correlation function spherical moments of order $l=0,1,2$. The\nexpansion coefficients through $\\beta^{15}$ for the vorticity are also\ntabulated. Our analysis of the series supports the Kosterlitz-Thouless\npredictions on the structure of the critical singularities and leads to fairly\naccurate estimates of the critical parameters.",
        "positive": "Axial Vector Form Factors of the Nucleon from Lattice QCD: We present results for the form factors of the isovector axial vector current\nin the nucleon state using large scale simulations of lattice QCD. The\ncalculations were done using eight ensembles of gauge configurations generated\nby the MILC collaboration using the HISQ action with 2+1+1 dynamical flavors.\nThese ensembles span three lattice spacings $a \\approx 0.06, 0.09$ and $0.12$\nfm and light-quark masses corresponding to the pion masses $M_\\pi \\approx 135,\n225$ and $310$ MeV. High-statistics estimates allow us to quantify systematic\nuncertainties in the extraction of $G_A(Q^2)$ and the induced pseudoscalar form\nfactor $\\tilde{G}_P(Q^2)$. We perform a simultaneous extrapolation in the\nlattice spacing, lattice volume and light-quark masses of the axial charge\nradius $r_A$ data to obtain physical estimates. Using the dipole ansatz to fit\nthe $Q^2$ behavior we obtain $r_A|_{\\rm dipole} = 0.49(3)$ fm, which\ncorresponds to ${\\cal M}_A = 1.39(9)$ GeV, and is consistent with ${\\cal M}_A =\n1.35(17)$ GeV obtained by the miniBooNE collaboration. The estimate obtained\nusing the $z$-expansion is $r_A|_{z-{\\rm expansion}} = 0.46(6)$ fm, and the\ncombined result is $r_A|_{\\rm combined} = 0.48(4)$ fm. Analysis of the induced\npseudoscalar form factor $\\tilde{G}_P(Q^2)$ yields low estimates for $g_P^\\ast$\nand $g_{\\pi {\\rm NN}}$ compared to their phenomenological values. To understand\nthese, we analyze the partially conserved axial current (PCAC) relation by also\ncalculating the pseudoscalar form factor. We find that these low values are due\nto large deviations in the PCAC relation between the three form factors and\nfrom the pion-pole dominance hypothesis."
    },
    {
        "anchor": "Chiral determinant on the lattice -- Anomalies and Instantons: An expression for the lattice effective action induced by chiral fermions in\nany even dimensions in terms of an overlap of two states is shown to have\npromising properties in two and four dimensions: The correct abelian anomaly is\nreproduced and gauge field configurations with non-zero topological charge are\ncompletely suppressed.",
        "positive": "Centre vortex removal restores chiral symmetry: The influence of centre vortices on dynamical chiral symmetry breaking is\ninvestigated through the light hadron spectrum on the lattice. Recent studies\nof the quark propagator and other quantities have provided evidence that centre\nvortices are the fundamental objects underpinning dynamical chiral symmetry\nbreaking in SU(3) gauge theory. For the first time, we use the chiral overlap\nfermion action to study the low-lying hadron spectrum on lattice ensembles\nconsisting of Monte Carlo, vortex-removed, and vortex-projected gauge fields.\nWe find that gauge field configurations consisting solely of smoothed centre\nvortices are capable of reproducing all the salient features of the hadron\nspectrum, including dynamical chiral symmetry breaking. The hadron spectrum on\nvortex-removed fields shows clear signals of chiral symmetry restoration at\nlight values of the bare quark mass, while at heavy masses the spectrum is\nconsistent with a theory of weakly-interacting constituent quarks."
    },
    {
        "anchor": "Entropy Density and Speed of Sound from Improved Energy-Momentum Tensor\n  in Lattice QCD: We present a lattice calculation of the entropy density $s/T^{3}$ and speed\nof sound $c_{s}^{2}$ of gluedynamics near the critical temperature, $T_{c}$, in\nthe deconfined phase. By exploring the temperature dependence of entropy\ndensity in this region, we aim to analyse the significant discrepancies between\nthe previous computations. The calculation of entropy density is carried out by\nnumerical simulations of $O(a^{4})$ mean-field improved energy-momentum tensor\n(EMT) of SU(3) gauge theory on the lattice. We expand on reaching $O(a^{4})$\nimprovement using tadpole-improved Symanzik action. The entropy density is\ncalculated directly from the expectation value of the space-time component of\nthe improved EMT in the presence of shifted boundary conditions at several\nlattice spacings ($a \\approx 0.043 - 0.012$ fm). The absence of ultraviolet\ndivergences and the minimal finite-size effects allow for the precision\ndetermination of the entropy density and its extrapolation to the continuum\nlimit. As expected, the resulting entropy density displays the expected\nbehaviour of rapid increase near the critical temperature in the deconfined\nphase followed by a slow increase in $2T_{c}\\leq T\\leq 3T_{c}$ region,\nsuggesting a logarithmic dependence on the temperature. A quantitative\ncomparison of $s/T^{3}$ shows good agreement with Pade approximation and\nlattice results of previous high-precision data obtained using the gradient\nflow method. We observe that at temperatures of about $3T_{c}$, deviations of\nentropy density from the Stefan-Boltzmann value for a free theory are about\n10$\\%$. It is shown that the speed of sound in SU(3) gluedynamics is found to\nbe $c_{s}^{2}\\leq 0.333$ in the temperature region $1.06T_{c}\\leq T\\leq\n3.05T_{c}$ explored in this study. The results are found to agree with the\ncorresponding analytic and numerical estimates.",
        "positive": "Transport coefficients from the lattice?: The prospects of extracting transport coefficients from euclidean lattice\nsimulations are discussed. Some general comments on the reconstruction of\nspectral functions using the Maximal Entropy Method are given as well."
    },
    {
        "anchor": "Confinement and scaling of the vortex vacuum of SU(2) lattice gauge\n  theory: The magnetic vortices which arise in SU(2) lattice gauge theory in center\nprojection are visualized for a given time slice. We establish that the number\nof vortices piercing a given 2-dimensional sheet is a renormalization group\ninvariant and therefore physical quantity. We find that roughly 2 vortices\npierce an area of 1 fm^2.",
        "positive": "Ising spins coupled to a four-dimensional discrete Regge skeleton: Regge calculus is a powerful method to approximate a continuous manifold by a\nsimplicial lattice, keeping the connectivities of the underlying lattice fixed\nand taking the edge lengths as degrees of freedom. The discrete Regge model\nemployed in this work limits the choice of the link lengths to a finite number.\nTo get more precise insight into the behavior of the four-dimensional discrete\nRegge model, we coupled spins to the fluctuating manifolds. We examined the\nphase transition of the spin system and the associated critical exponents. The\nresults are obtained from finite-size scaling analyses of Monte Carlo\nsimulations. We find consistency with the mean-field theory of the Ising model\non a static four-dimensional lattice."
    },
    {
        "anchor": "Putting M theory on a computer: We propose a non-lattice simulation for studying supersymmetric matrix\nquantum mechanics in a non-perturbative manner. In particular, our method\nenables us to put M theory on a computer based on its matrix formulation\nproposed by Banks, Fischler, Shenker and Susskind. Here we present Monte Carlo\nresults of the same matrix model but in a different parameter region, which\ncorresponds to the 't Hooft large-N limit at finite temperature. In the strong\ncoupling limit the model has a dual description in terms of the N D0-brane\nsolution in 10d type IIA supergravity. Our results provide highly nontrivial\nevidences for the conjectured duality. In particular, the energy (and hence the\nentropy) of the non-extremal black hole has been reproduced by solving directly\nthe strongly coupled dynamics of the D0-brane effective theory.",
        "positive": "QED Corrections to Hadronic Processes in Lattice QCD: In this paper, for the first time a method is proposed to compute\nelectromagnetic effects in hadronic processes using lattice simulations. The\nmethod can be applied, for example, to the leptonic and semileptonic decays of\nlight or heavy pseudoscalar mesons. For these quantities the presence of\ninfrared divergences in intermediate stages of the calculation makes the\nprocedure much more complicated than is the case for the hadronic spectrum, for\nwhich calculations already exist. In order to compute the physical widths,\ndiagrams with virtual photons must be combined with those corresponding to the\nemission of real photons. Only in this way do the infrared divergences cancel\nas first understood by Bloch and Nordsieck in 1937. We present a detailed\nanalysis of the method for the leptonic decays of a pseudoscalar meson. The\nimplementation of our method, although challenging, is within reach of the\npresent lattice technology."
    },
    {
        "anchor": "Non-perturbative determinations of $B$-meson decay constants and\n  semi-leptonic form factors: $B$-physics is one of the most promising windows to find new physics in the\nflavor sector. One key ingredient to these searches are precise theoretical\npredictions derived from the Standard Model. Focusing at the nonperturbative\nQCD contributions, we carry out lattice QCD simulations in order to calculate\n$B$-meson decay constants and semi-leptonic form factors. Combined with\nexperimental measurements our results enable us to determine CKM matrix\nelements.\n  Here we present $B$ and $B_s$ meson decay constants as well as semi-leptonic\nform factors including rare decays, CKM or GIM suppressed in the Standard\nModel. Our results are based on the set of 2+1 flavor domain-wall Iwasaki gauge\nfield configurations generated by the RBC-UKQCD collaboration. Heavy $b$-quarks\nare simulated using the relativistic heavy quark action.",
        "positive": "Roberge-Weiss transition in $N_\\text{f}=2$ QCD with Wilson fermions and\n  $N_\u03c4=6$: QCD with imaginary chemical potential is free of the sign problem and\nexhibits a rich phase structure constraining the phase diagram at real chemical\npotential. We simulate the critical endpoint of the Roberge-Weiss (RW)\ntransition at imaginary chemical potential for $N_\\text{f}=2$ QCD on $N_\\tau=6$\nlattices with standard Wilson fermions. As found on coarser lattices, the RW\nendpoint is a triple point connecting the deconfinement/chiral transitions in\nthe heavy/light quark mass regions and changes to a second-order endpoint for\nintermediate masses. These regimes are separated by two tricritical values of\nthe quark mass, which we determine by extracting the critical exponent $\\nu$\nfrom a systematic finite size scaling analysis of the Binder cumulant of the\nimaginary part of the Polyakov loop. We are able to explain a previously\nobserved finite size effect afflicting the scaling of the Binder cumulant in\nthe regime of three-phase coexistence. Compared to $N_\\tau=4$ lattices, the\ntricritical masses are shifted towards smaller values. Exploratory results on\n$N_\\tau=8$ as well as comparison with staggered simulations suggest that\nsignificantly finer lattices are needed before a continuum extrapolation\nbecomes feasible."
    },
    {
        "anchor": "Random Matrix Theory, Chiral Perturbation Theory, and Lattice Data: Recently, the chiral logarithms predicted by quenched chiral perturbation\ntheory have been extracted from lattice calculations of hadron masses. We argue\nthat the deviations of lattice results from random matrix theory starting\naround the so-called Thouless energy can be understood in terms of chiral\nperturbation theory as well. Comparison of lattice data with chiral\nperturbation theory formulae allows us to compute the pion decay constant. We\npresent results from a calculation for quenched SU(2) with Kogut-Susskind\nfermions at \\beta=2.0 and 2.2.",
        "positive": "$K \\to \u03c0$ semileptonic form factors with $N_f=2+1+1$ Twisted Mass\n  fermions: We present a lattice QCD determination of the vector and scalar form factors\nof the semileptonic $K \\to \\pi \\ell \\nu$ decay which are relevant for the\nextraction of the CKM matrix element $|V_{us}|$ from experimental data. Our\nresults are based on the gauge configurations produced by the European Twisted\nMass Collaboration with $N_f = 2+1+1$ dynamical fermions, which include in the\nsea, besides two light mass degenerate quarks, also the strange and the charm\nquarks. We use data simulated at three different values of the lattice spacing\nand with pion masses as small as $210$ MeV. Our final result for the vector\nform factor at zero momentum transfer is $f_+(0) = 0.9709 (46)$, where the\nuncertainty is both statistical and systematic combined in quadrature. Using\nthe latest experimental value of $f_+(0) |V_{us}|$ from $K_{\\ell 3}$ decays, we\nobtain $|V_{us}| = 0.2230 (11)$, which allows to test the unitarity constraint\nof the Standard Model below the permille level once the determination of\n$|V_{ud}|$ from superallowed nuclear $\\beta$ decays is adopted. A slight\ntension with unitarity at the level of $\\sim 2$ standard deviations is\nobserved. Moreover we present our results for the semileptonic scalar\n$f_0(q^2)$ and vector $f_+(q^2)$ form factors in the whole range of values of\nthe squared four-momentum transfer $q^2$ measured in $K_{\\ell 3}$ decays,\nobtaining a very good agreement with the momentum dependence of the\nexperimental data. We provide a set of synthetic data points representing our\nresults for the vector and scalar form factors at the physical point for\nseveral selected values of $q^2$."
    },
    {
        "anchor": "Finite Temperature Phase Transition in SU(2) Lattice Gauge Theory with\n  Extended Action: We study the three dimensional fundamental-adjoint $SU(2)$ lattice gauge\ntheory at finite temperature by Monte Carlo simulations. We find that the\nfinite temperature deconfinement phase transition line joins the first order\nbulk phase transition line at its endpoint. Moreover, across the bulk\ntransition line, the Polyakov loop undergoes a discontinuous jump implying the\nexistence of both confining and deconfining phases on its two sides.\nImplications for universality and the nature of the confining-deconfining\ntransition are discussed.",
        "positive": "Lattice study of Weak First Order Phase Transitions in D=4: The properties of several phase transitions relevant to the lattice study of\nQuantum Field Theory are investigated."
    },
    {
        "anchor": "O(a) improvement of the HYP static axial and vector currents at one-loop\n  order of perturbation theory: We calculate analytically the improvement coefficients of the static axial\nand vector currents in O(a) improved lattice QCD at one-loop order of\nperturbation theory. The static quark is described by the hypercubic action,\npreviously introduced in the literature in order to improve the signal-to-noise\nratio of static observables. Within a Schroedinger Functional setup, we derive\nthe Feynman rules of the hypercubic link in time-momentum representation. The\nimprovement coefficients are obtained from on-shell correlators of the static\naxial and vector currents. As a by-product, we localise the minimum of the\nstatic self-energy as a function of the smearing parameters of the action at\none-loop order and show that the perturbative minimum is close to its\nnon-perturbative counterpart.",
        "positive": "A finite-volume matrix Hamiltonian model for a Delta -> nucleon-pion\n  system: A matrix Hamiltonian model is developed to address the finite-volume effects\nappearing in studies of baryon resonances in lattice QCD. The Hamiltonian model\nincludes interaction terms in a transparent way, and can be readily generalized\nto address multi-channel problems. The eigenvalue equation of the model is\nexactly solvable, and can be matched onto chiral effective field theory. The\nmodel is investigated in the case of Delta -> nucleon-pion scattering. A robust\nmethod for determining the resonance parameters from lattice QCD is developed.\nIt involves constraining the free parameters of the model based on the lattice\nspectrum in question. The method is tested in the context of a set of\npseudodata, and a picture of the model-dependence is obtained by examining a\nvariety of regularization schemes in the model. A comparison is made with the\nLuescher method, and it is found that the matrix Hamiltonian method is equally\nrobust. Both methods are tested in a more realistic scenario, where a\nbackground interaction corresponding to direct nucleon-pion scattering is\nincorporated into the pseudodata. The resulting extraction of the resonance\nparameters associated with the Delta baryon resonance provides evidence that an\neffective field theory style of approach yields a successful realization of\nfinite-volume effects in the context of baryon resonances."
    },
    {
        "anchor": "Lattice QCD$_2$ effective action with Bogoliubov transformations: In the Wilson's lattice formulation of QCD, a fermionic Fock space of states\ncan be explicitly built at each time slice using canonical creation and\nannihilation operators. The partition function $Z$ is then represented as the\ntrace of the transfer matrix, and its usual functional representation as a path\nintegral of $\\exp(- S)$ can be recovered in a standard way. However, applying a\nBogoliubov transformation on the canonical operators before passing to the\nfunctional formalism, we can isolate a vacuum contribution in the resulting\naction which depends only on the parameters of the transformation and fixes\nthem via a variational principle. Then, inserting in the trace defining $Z$ an\noperator projecting on the mesons subspace at each time slice and making the\nphysical assumption that the true partition function is well approximate by the\nprojected one, we can also write an effective quadratic action for mesons. We\ntested the method in the renowned 't Hooft model, namely QCD in two spacetime\ndimensions for large number of colours, in Coulomb gauge.",
        "positive": "Emerging understanding of the \u0394I = 1/2 Rule from Lattice QCD: There has been much speculation as to the origin of the \\Delta I = 1/2 rule\n(Re A_0/Re A_2 \\simeq 22.5). We find that the two dominant contributions to the\n\\Delta I=3/2, K \\to \\pi \\pi{} correlation functions have opposite signs leading\nto a significant cancellation. This partial cancellation occurs in our\ncomputation of Re A_2 with physical quark masses and kinematics (where we\nreproduce the experimental value of A_2) and also for heavier pions at\nthreshold. For Re A_0, although we do not have results at physical kinematics,\nwe do have results for pions at zero-momentum with m_\\pi{} \\simeq 420 MeV (Re\nA_0/Re A_2=9.1(2.1)) and m_\\pi{} \\simeq 330 MeV (Re A_0/Re A_2=12.0(1.7)). The\ncontributions which partially cancel in Re A_2 are also the largest ones in Re\nA_0, but now they have the same sign and so enhance this amplitude. The\nemerging explanation of the \\Delta I=1/2 rule is a combination of the\nperturbative running to scales of O(2 GeV), a relative suppression of Re A_2\nthrough the cancellation of the two dominant contributions and the\ncorresponding enhancement of Re A_0. QCD and EWP penguin operators make only\nvery small contributions at such scales."
    },
    {
        "anchor": "Equation of State for Spin Systems with Goldstone Bosons: the 3d O(4)\n  Case: We propose an improved parametric form for the equation of state of\nthree-dimensional O(N) spin systems. The proposed form is a series expansion\nwith two sets of terms, which contribute (mainly) separately to the description\nof the high- and low-temperature regions of the phase diagram. Our goal is a\nbetter description of the low-temperature phase at zero magnetic field (i.e.\nthe coexistence line), characterized by singularities induced by Goldstone\nmodes. We test our proposed form by comparison with existing Monte Carlo data\nfor the N=4 case, which is of interest in studies of the QCD phase transition\nand for which the Goldstone-mode effects are quite pronounced. We find that the\ndescription of the numerical equation of state is indeed improved with respect\nto other fitting forms. In all cases considered we determine the coefficients\nnonperturbatively, from fits to the data. As a consequence, we are able to\nobtain a very precise characterization of the pseudo-critical line for the\nmodel.",
        "positive": "Using Wilson flow to study the SU(3) deconfinement transition: We explore the use of Wilson flow to study the deconfinement transition in\nSU(3) gauge theory. We use the flowed Polyakov loop as a renormalized order\nparameter for the transition, and use it to renormalize the Polyakov loop. We\nalso study the flow properties of the electric and magnetic gluon condensates,\nand demonstrate that the difference of the flowed operators shows rapid change\nacross the transition point."
    },
    {
        "anchor": "Non-perturbative quark mass renormalization in two-flavor QCD: The running of renormalized quark masses is computed in lattice QCD with two\nflavors of massless O(a) improved Wilson quarks. The regularization and flavor\nindependent factor that relates running quark masses to the renormalization\ngroup invariant ones is evaluated in the Schroedinger Functional scheme. Using\nexisting data for the scale r_0 and the pseudoscalar meson masses, we define a\nreference quark mass in QCD with two degenerate quark flavors. We then compute\nthe renormalization group invariant reference quark mass at three different\nlattice spacings. Our estimate for the continuum value is converted to the\nstrange quark mass with the help of chiral perturbation theory.",
        "positive": "Short Distance Repulsion Among Baryons: We review recent investigations on the short distance behaviors of potentials\namong baryons, which are formulated through the Nambu-Bethe-Salpeter (NBS) wave\nfunction. After explaining the method to define the potentials, we analyze the\nshort distance behavior of the NBS wave functions and the corresponding\npotentials by combining the operator product expansion and a renormalization\ngroup analysis in the perturbation theory of QCD. These analytic results are\ncompared with numerical results obtained in lattice QCD simulations."
    },
    {
        "anchor": "Calculation of the continuum--lattice HQET matching for the complete\n  basis of four--fermion operators: reanalysis of the $B^{0}$-$\\bar{B}^{0}$\n  mixing: In this work, we find the expressions of continuum HQET four-fermion\noperators in terms of lattice operators in perturbation theory. To do so, we\ncalculate the one--loop continuum--lattice HQET matching for the complete basis\nof $\\Delta B=2$ and $\\Delta B=0$ operators (excluding penguin diagrams),\nextending and completing previous studies. We have also corrected some errors\nin previous evaluations of the matching for the operator $O_{LL}$. Our results\nare relevant to the lattice computation of the values of unknown hadronic\nmatrix elements which enter in many very important theoretical predictions in\n$B$--meson phenomenology: $B^{0}$-$\\bar{B}^{0}$ mixing, $\\tau_{B}$ and\n$\\tau_{B_{s}}$ lifetimes, SUSY effects in $\\Delta B=2$ transitions and the\n$B_{s}$ width difference $\\Delta \\Gamma_{B_{s}}$. We have reanalyzed our\nlattice data for the $B_{B}$ parameter of the $B^{0}$-$\\bar{B}^{0}$ mixing on\n600 lattices of size $24^{3}\\times 40$ at $\\beta=6.0$ computed with the\nSW-Clover and HQET lattice actions. We have used the correct lattice--continuum\nmatching factors and boosted perturbation theory with tadpole improved\nheavy--light operators to reduce the systematic error in the evaluation of the\nrenormalization constants. Our best estimate of the renormalization scale\nindependent $B$--parameter is $\\hat{B}_{B} = 1.29 \\pm 0.08 \\pm 0.06$, where the\nfirst error is statistical and the second is systematic coming from the\nuncertainty in the determination of the renormalization constants. Our result\nis in good agreement with previous results obtained by extrapolating Wilson\ndata. As a byproduct, we also obtain the complete one--loop anomalous dimension\nmatrix for four--fermion operators in the HQET.",
        "positive": "Numerical simulation of the Kardar-Parisi-Zhang equation: We simulate the Kardar-Parisi-Zhang equation in 2+1 dimensions. The Hopf-Cole\ntransformation is used in order to obtain a stable numerical scheme. The two\nrelevant critical exponents are precisely measured. (2 PostScript figures\navailable from the authors)"
    },
    {
        "anchor": "Finite-Size Scaling Study of the Three-Dimensional Classical Heisenberg\n  Model: We use the single-cluster Monte Carlo update algorithm to simulate the\nthree-dimensional classical Heisenberg model in the critical region on simple\ncubic lattices of size $L^3$ with $L=12, 16, 20, 24, 32, 40$, and $48$. By\nmeans of finite-size scaling analyses we compute high-precision estimates of\nthe critical temperature and the critical exponents, using extensively\nhistogram reweighting and optimization techniques. Measurements of the\nautocorrelation time show the expected reduction of critical slowing down at\nthe phase transition. This allows simulations on significantly larger lattices\nthan in previous studies and consequently a better control over systematic\nerrors in finite-size scaling analyses.",
        "positive": "The supersymmetric Ward identities on the lattice: Supersymmetric (SUSY) Ward identities are considered for the N=1 SU(2) SUSY\nYang Mills theory discretized on the lattice with Wilson fermions (gluinos).\nThey are used in order to compute non-perturbatively a subtracted gluino mass\nand the mixing coefficient of the SUSY current. The computations were performed\nat gauge coupling $\\beta$=2.3 and hopping parameter $\\kappa$=0.1925, 0.194,\n0.1955 using the two-step multi-bosonic dynamical-fermion algorithm. Our\nresults are consistent with a scenario where the Ward identities are satisfied\nup to O(a) effects. The vanishing of the gluino mass occurs at a value of the\nhopping parameter which is not fully consistent with the estimate based on the\nchiral phase transition. This suggests that, although SUSY restoration appears\nto occur close to the continuum limit of the lattice theory, the results are\nstill affected by significant systematic effects."
    },
    {
        "anchor": "SW action for the lattice Schwinger model: We study some aspects of the ${\\cal O}(a)$ improved Sheikholeslami-Wohlert\n(SW) action for the lattice Schwinger model. We find some improvement\nconcerning the distribution of eigenvalues of the Dirac operator and of the\nmasses but little or no improvement for rotational invariance of correlators or\ndispersion relations.",
        "positive": "$\u03c0$N and strangeness sigma terms at the physical point with chiral\n  fermions: Lattice QCD calculations with chiral fermions of the $\\pi$N sigma term\n$\\sigma_{\\pi N}$ and strangeness sigma term $\\sigma_{sN}$ including chiral\ninterpolation with continuum and volume corrections are provided in this work,\nwith the excited-state contaminations subtracted properly. We calculate the\nscalar matrix element for the light/strange quark directly and find\n$\\sigma_{\\pi N}=45.9(7.4)(2.8)$ MeV, with the disconnected insertion part\ncontributing 20(12)(4)\\%, and $\\sigma_{sN}=40.2(11.7)(3.5)$ MeV, which is\nsomewhat smaller than $\\sigma_{\\pi N}$. The ratio of the strange/light scalar\nmatrix elements is $y$ = 0.09(3)(1)."
    },
    {
        "anchor": "Excited Baryons from the FLIC Fermion Action: Masses of positive and negative parity excited nucleons and hyperons are\ncalculated in quenched lattice QCD using an O(a^2) improved gluon action and a\nfat-link clover fermion action in which only the irrelevant operators are\nconstructed with fat links. The results are in agreement with earlier N*\nsimulations with improved actions, and exhibit a clear mass splitting between\nthe nucleon and its parity partner, as well as a small mass splitting between\nthe two low-lying J^P={1/2}^- N* states. Study of different Lambda\ninterpolating fields suggests a similar splitting between the lowest two\n{1/2}^- Lambda* states, although the empirical mass suppression of the\nLambda*(1405) is not seen.",
        "positive": "Phase structure and Higgs boson mass in a Higgs-Yukawa model with a\n  dimension-6 operator: We investigate the impact of a $\\lambda_6 \\varphi^6$ term included in a\nchirally invariant lattice Higgs-Yukawa model. Such a term could emerge from\nBSM physics at some larger energy scale. We map out the phase structure of the\nHiggs-Yukawa model with positive $\\lambda_6$ and negative quartic self coupling\nof the scalar fields. To this end, we evaluate the constraint effective\npotential in lattice perturbation theory and also determine the magnetization\nof the model via numerical simulations which allow us to reach also\nnon-perturbative values of the couplings. As a result, we find a complex phase\nstructure with first and second order phase transitions identified through the\nmagnetization. Further we analyze the effect of such a $\\varphi^6$ term on the\nlower Higgs boson mass bound to see, whether the standard model lower mass\nbound can be altered."
    },
    {
        "anchor": "Mean distribution approach to spin and gauge theories: We formulate self-consistency equations for the distribution of links in spin\nmodels and of plaquettes in gauge theories. This improves upon known\nmean-field, mean-link, and mean-plaquette approximations in such that we\nself-consistently determine all moments of the considered variable instead of\njust the first. We give examples in both Abelian and non-Abelian cases.",
        "positive": "QCD thermodynamics with Wilson quarks at large kappa: We have extended our study of the high temperature transition with two\nflavors of Wilson quarks on 12^3 x 6 lattices to kappa=0.19. We have also\nperformed spectrum calculations on 12^3 x 24 lattices at kappa=0.19 to find the\nphysical lattice spacing and quark mass. At this value of kappa the transition\nis remarkable in that the plaquette and psi-bar-psi show a large discontinuity\nwhile the Polyakov loop changes very little. This and several other features of\nthe transition are more suggestive of a bulk transition than a transition to a\nquark-gluon plasma. However, if the temperature is estimated using the rho mass\nas a standard, the result is about 150 MeV, in agreement with the value found\nfor the thermal transition with Kogut-Susskind quarks. uuencoded compressed\nPostscript file"
    },
    {
        "anchor": "Equivalence of relativistic three-particle quantization conditions: We show that a recently derived alternative form of the relativistic\nthree-particle quantization condition for identical particles can be rewritten\nin terms of the R matrix introduced to give a unitary representation of the\ninfinite-volume three-particle scattering amplitude. Combined with earlier\nwork, this shows the equivalence of the relativistic effective field theory\napproach of Hansen and Sharpe (Refs.[1,2]) and the \"finite-volume unitarity\"\napproach of Mai and D\\\"oring (Refs.[3,4]). It also provides a generalization of\nthe latter approach to arbitrary angular momenta of two-particle subsystems.",
        "positive": "Supersymmetric Lattice Theories: Contribution to Snowmass 2022: In this white paper we summarise the construction and applications of lattice\ntheories possessing exact supersymmetry focusing, in particular, on N=4\nYang-Mills theory. Lattice formulations of this theory allow for numerical\nsimulation of the theory at strong coupling and hence give a window on\nnon-perturbative physics away from the planar limit. This has important\napplications to our understanding of holographic approaches to quantum gravity\nand conformal field theories."
    },
    {
        "anchor": "Phase structure of $\\mathcal{N}$=1 super Yang-Mills theory from the\n  gradient flow: Composite operators of bare fermion fields evolved along a trajectory on\nfield space by means of flow equations are multiplicatively renormalized.\nTherefore, even in the case of Wilson fermions, the renormalization of\nexpectation values of fermion operators can be drastically simplified on the\nlattice. We measure the gluino condensate in $\\mathcal{N}$=1 supersymmetric\nYang-Mills theory at non-zero temperatures by means of the gradient flow. The\nnon-vanishing expectation value of the gluino condensate up to a certain\ncritical temperature is a signal of chiral symmetry breaking, in agreement with\ntheoretical conjectures on the vacuum structure of the theory. Furthermore, the\ndeconfinement phase transition seems to occur close to this critical\ntemperature, meaning that in $\\mathcal{N}$=1 SYM the phases of broken chiral\nsymmetry and of confinement would coincide.",
        "positive": "Nucleon electromagnetic form factors in two-flavour QCD: We present results for the nucleon electromagnetic form factors, including\nthe momentum transfer dependence and derived quantities (charge radii and\nmagnetic moment). The analysis is performed using O(a) improved Wilson fermions\nin Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a\nsystematic evaluation of the influence of excited states in three-point\ncorrelation functions, which lead to a biased evaluation, if not accounted for\ncorrectly. We argue that the use of summed operator insertions and fit\nans\\\"atze including excited states allow us to suppress and control this\neffect. We employ a novel method to perform joint chiral and continuum\nextrapolations, by fitting the form factors directly to the expressions of\ncovariant baryonic chiral effective field theory. The final results for the\ncharge radii and magnetic moment from our lattice calculations include, for the\nfirst time, a full error budget. We find that our estimates are compatible with\nexperimental results within their overall uncertainties."
    },
    {
        "anchor": "Fine tuned vortices in lattice SU(2) gluodynamics: We report measurements of the action associated with center vortices in SU(2)\npure lattice gauge theory. In the lattice units the excess of the action on the\nplaquettes belonging to the vortex is approximately a constant, independent on\nthe lattice spacing 'a'. Therefore the action of the center vortex is of order\n'A/a^2', where 'A' is its area. Since the area 'A' is known to scale in the\nphysical units, the measurements imply that the suppression due to the surface\naction is balanced, or fine tuned to the entropy factor which is to be an\nexponential of 'A/a^2'.",
        "positive": "Nucleon form factors in $N_f=2+1$ lattice QCD at the physical point :\n  finite lattice spacing effect on the root-mean-square radii: We present results for the nucleon form factors: electric ($G_E$), magnetic\n($G_M$), axial ($F_A$), induced pseudoscalar ($F_P$) and pseudoscalar ($G_P$)\nform factors, using the second PACS10 ensemble that is one of three sets of\n$2+1$ flavor lattice QCD configurations at physical quark masses in large\nspatial volumes (exceeding $(10\\ \\mathrm{fm})^3$). The second PACS10 gauge\nconfigurations are generated by the PACS Collaboration with the six\nstout-smeared $O(a)$ improved Wilson quark action and Iwasaki gauge action at\nthe second gauge coupling $\\beta=2.00$ corresponding to the lattice spacing of\n$a=0.063$ fm. We determine the isovector electric, magnetic and axial radii and\nmagnetic moment from the corresponding form factors, as well as the\naxial-vector coupling $g_A$. Combining our previous results for the coarser\nlattice spacing [E. Shintani et al., Phys. Rev. D99 (2019) 014510; Phys. Rev.\nD102 (2020) 019902 (erattum)], the finite lattice spacing effects on the\nisovector radii, magnetic moment and axial-vector coupling are investigated\nusing the difference between the two results. It was found that the effect on\n$g_A$ is kept smaller than the statistical error of 2% while the effect on the\nisovector radii was observed as a possible discretization error of about 10%,\nregardless of the channel. We also report the partially conserved axial vector\ncurrent (PCAC) relation using a set of nucleon three-point correlation\nfunctions in order to verify the effect by $O(a)$-improvement of the\naxial-vector current."
    },
    {
        "anchor": "QCD thermodynamics at zero and non-zero density: We present results on the QCD equation of state, obtained with two different\nimproved dynamical staggered fermion actions and almost physical quark masses.\nLattice cut-off effects are discussed in detail as results for three different\nlattice spacings are available now, i.e. results have been obtained on lattices\nwith temporal extent of $N_\\tau=4,6$ and 8. Furthermore we discuss the Taylor\nexpansion approach to non-zero baryon chemical potential by means of an\nexpansion of the pressure. We use the expansion coefficients to calculate\nvarious fluctuations and correlations among hadronic charges. We find that the\ncorrelations reproduce the qualitative behavior of the resonance gas model\nbelow $T_c$ and start to agree with the free gas predictions for $T\\gsim\n1.5T_c$.",
        "positive": "Leptonic decays of $B_{(s)}$ and $D_{(s)}$ using the OK action: We present recent progress in the lattice calculation of leptonic decay\nconstants for $B_{(s)}$ and $D_{(s)}$ mesons using the Oktay-Kronfeld (OK)\naction for charm and bottom valence quarks, whose masses are tuned\nnon-perturbatively. The calculations are done on 6 HISQ ensembles generated by\nthe MILC collaboration with $N_f=2+1+1$ flavors. We also use the HISQ action\nfor the light spectator quarks. Results are presented for the ratios\n$f_{B_s}/f_B$ and $f_{D_s}/f_D$, which reflect $SU(3)$ flavor symmetry\nbreaking, and are independent of the renormalization constants of the axial\ncurrents."
    },
    {
        "anchor": "Review on Composite Higgs Models: Composite Higgs Models explore the possibility that the Higgs boson is an\nexcitation of a new strongly interacting sector giving rise to electro-weak\nsymmetry breaking. After describing how this new sector can be embedded into\nthe Standard Model of elementary particle physics meeting experimental\nconstraints, I will review efforts by the community to explore the physics of\nthe new strong interaction using methods of lattice field theory. Challenges in\nunderstanding the numerical results are discussed and an outlook is given on\npossible future directions allowing to confirm or reject the composite Higgs\nhypothesis.",
        "positive": "Latest lattice results of N=1 supersymmetric Yang-Mills theory with some\n  topological insights: We summarise the latest results of our collaboration concerning N=1\nsupersymmetric Yang-Mills theory in four dimensions on the lattice. We\ninvestigate the expected formation of supersymmetric multiplets of the lightest\nparticles and the behaviour of the topological susceptibility approaching the\nsupersymmetric limit of the theory."
    },
    {
        "anchor": "Progress in complex Langevin simulations of full QCD at nonzero density: Progress in the application of the complex Langevin method to full QCD at\nnon-zero chemical potential is reported. The method evades the sign problem\nwhich makes naive simulations at nonzero density impossible. The procedure\n'gauge cooling' is used to stabilize the simulations at small enough lattice\nspacings. The method allows simulations also at high densities, all the way up\nto saturation. Simulations in a systematic hopping parameter expansion are also\nperformed and good convergence is observed, validating the full as well as the\nexpanded simulations.",
        "positive": "Simulation of Scalar Field Theories with Complex Actions: Many scalar field theory models with complex actions are invariant under the\nantilinear ($PT$) symmetry operation $L^{\\ast}(-\\chi)=L(\\chi)$. Models in this\nclass include the $i\\phi^{3}$ model, the Bose gas at finite density and\nPolyakov loop spin models at finite density. This symmetry may be used to\nobtain a dual representation where weights in the functional integral are real\nbut not necessarily positive. For a subclass of models satisfying a dual\npositive weight condition, the partition function is manifestly positive. The\nsign problem is eliminated; such models are easily simulated by a simple local\nalgorithm in any number of dimensions. Simulations of models in this subclass\nshow a rich set of behaviors. Propagators may exhibit damped oscillations,\nindicating a clear violation of spectral positivity. Pattern formation may also\noccur, with both stripe and bubble morphologies possible. The existence of a\npositive representation is constrained by Lee-Yang zeros: a positive\nrepresentation cannot exist everywhere in the neighborhood of such a zero.\nSimulation results raise the possibility that pattern-forming behavior may\noccur in finite density QCD in the vicinity of the critical line."
    },
    {
        "anchor": "A New Look at the Axial Anomaly in Lattice QED with Wilson Fermions: By carrying out a systematic expansion of Feynman integrals in the lattice\nspacing, we show that the axial anomaly in the U(1) lattice gauge theory with\nWilson fermions, as determined in one-loop order from an irrelevant lattice\noperator in the Ward identity, must necessarily be identical to that computed\nfrom the dimensionally regulated continuum Feynman integrals for the triangle\ndiagrams.",
        "positive": "Nuclear models on a lattice: We present the first results of a quantum field approach to nuclear models\nobtained by lattice techniques. Renormalization effects for fermion mass and\ncoupling constant in case of scalar and pseudoscalar interaction lagrangian\ndensities are discussed."
    },
    {
        "anchor": "The Static Quark Potential from the Gauge Independent Abelian\n  Decomposition: We investigate the relationship between colour confinement and the gauge\nindependent Cho-Duan-Ge Abelian decomposition.\n  The decomposition is defined in terms of a colour field $n$; the principle\nnovelty of our study is that we have defined this field in terms of the\neigenvectors of the Wilson Loop. This establishes an equivalence between the\npath ordered integral of the non-Abelian gauge fields with an integral over an\nAbelian restricted gauge field which is tractable both theoretically and\nnumerically in lattice QCD. We circumvent path ordering without needing an\nadditional path integral. By using Stokes' theorem, we can compute the Wilson\nLoop in terms of a surface integral over a restricted field strength, and show\nthat the restricted field strength may be dominated by certain structures,\nwhich occur when one of the quantities parametrising the colour field $n$ winds\nitself around a non-analyticity in the colour field. If they exist, these\nstructures will lead to a area law scaling for the Wilson Loop and provide a\nmechanism for quark confinement.\n  We search for these structures in quenched lattice QCD. We perform the\nAbelian decomposition, and compare the electric and magnetic fields with the\npatterns expected theoretically. We find that the restricted field strength is\ndominated by objects which may be peaks a single lattice spacing in size or\nextended string-like lines of electromagnetic flux. The objects are not\nisolated monopoles, as they generate electric fields in addition to magnetic\nfields, and the fields are not spherically symmetric, but may be either caused\nby a monopole/anti-monopole condensate, some other types of topological objects\nor a combination of these. Removing these peaks removes the area law scaling of\nthe string tension, suggesting that they are responsible for confinement.",
        "positive": "Remnant Symmetry and the Confinement Phase in Coulomb Gauge: We report on connections between the confining color Coulomb potential,\ncenter vortices, and the unbroken realization of remnant gauge symmetry in\nCoulomb gauge."
    },
    {
        "anchor": "Distribution Amplitudes of Pseudoscalar Mesons: We present results for the first two moments of the distribution amplitudes\nof pseudoscalar mesons. Using two flavors of non-perturbatively improved clover\nfermions and non-perturbative renormalization of the matrix elements we perform\nboth chiral and continuum extrapolations and compare with recent results from\nmodels and experiments.",
        "positive": "On the continuum limit of fermionic topological charge in lattice gauge\n  theory: It is proved that the fermionic topological charge of SU(N) lattice gauge\nfields on the 4-torus, given in terms of a spectral flow of the Hermitian\nWilson--Dirac operator, or equivalently, as the index of the Overlap Dirac\noperator, reduces to the continuum topological charge in the classical\ncontinuum limit when the parameter $m_0$ is in the physical region $0<m_0<2$."
    },
    {
        "anchor": "The Planar Thirring Model with K\u00e4hler-Dirac Fermions: K\\\"ahler's geometric approach in which relativistic fermion fields are\ntreated as differential forms is applied in three spacetime dimensions. It is\nshown that the resulting continuum theory is invariant under global\nU($N)\\otimes$U($N)$ field transformations, and has a parity-invariant mass\nterm, both symmetries shared in common with staggered lattice fermions. The\nformalism is used to construct a version of the Thirring model with contact\ninteractions between conserved Noether currents. Under reasonable assumptions\nabout field rescaling after quantum corrections, a more general interaction\nterm is derived, sharing the same symmetries but now including terms which\nentangle spin and taste degrees of freedom, which exactly coincides with the\nleading terms in the staggered lattice Thirring model in the long-wavelength\nlimit. Finally truncated versions of the theory are explored; it is found that\nexcluding scalar and pseudoscalar components leads to a theory of six-component\nfermion fields describing particles with spin 1, with fermion and antifermion\ncorresponding to states with definite circular polarisation. In the UV limit\nonly transverse states with just four non-vanishing components propagate.\nImplications for the description of dynamics at a strongly interacting\nrenormalisation-group fixed point are discussed.",
        "positive": "Topological susceptibility of $2d~\\mathrm{CP}^1$ or $\\mathrm{O}(3)$\n  non-linear $\u03c3$-model: is it divergent or not?: The topological susceptibility of $2d$ $\\mathrm{CP}^{N-1}$ models is\nexpected, based on perturbative computations, to develop a divergence in the\nlimit $N \\to 2$, where these models reduce to the well-known non-linear\n$\\mathrm{O}(3)$ $\\sigma$-model. The divergence is due to the dominance of\ninstantons of arbitrarily small size and its detection by numerical lattice\nsimulations is notoriously difficult, because it is logarithmic in the lattice\nspacing. We approach the problem from a different perspective, studying the\nbehavior of the model when the volume is fixed in dimensionless lattice units,\nwhere perturbative predictions are turned into more easily checkable behaviors.\nAfter testing this strategy for $N = 3$ and $4$, we apply it to $N = 2$,\nadopting at the same time a multicanonic algorithm to overcome the problem of\nrare topological fluctuations on asymptotically small lattices. Our final\nresults fully confirm, by means of purely non-perturbative methods, the\ndivergence of the topological susceptibility of the $2d$ $\\mathrm{CP}^1$ model."
    },
    {
        "anchor": "Flavor-Parity Breaking in the NJL Model with Wilson Fermions: The Nambu--Jona-Lasinio model is chirally symmetric. Addition of a Wilson\nterm explicitly breaks this symmetry and leaves the model with a remaining\nparity-flavor symmetry. In the approximation of a large number of colors it has\nbeen shown that there is a phase where the remaining parity-flavor symmetry is\nspontaneously broken and that on the phase boundary all pions become massless.\nUsing numerical simulations we confirm the existence of this phase for the case\nof two flavors and two colors. We also confirm the large N prediction of the\nexistence of large finite size effects that alter the shape of the phase\nboundary dramatically when periodic boundary conditions are used.",
        "positive": "Localisation, chiral symmetry and confinement in QCD and related\n  theories: I discuss recent results on the relation between the localisation of\nlow-lying Dirac eigenmodes, the restoration of chiral symmetry, and\ndeconfinement in QCD and QCD-like models, providing evidence of a close\nconnection between the three phenomena."
    },
    {
        "anchor": "Domain-Wall Fermion with $ R_5 $ Symmetry: We present the domain-wall fermion operator which is reflection symmetric in\nthe fifth dimension, with the approximate sign function $ S(H) $ of the\neffective 4-dimensional Dirac operator satisfying the bound $ |1-S(\\lambda)|\n\\le 2 d_Z $ for $ \\lambda^2 \\in [\\lambda_{min}^2, \\lambda_{max}^2] $, where $\nd_Z $ is the maximum deviation $ | 1- \\sqrt{x} R_Z(x) |_{\\rm max} $ of the\nZolotarev optimal rational polynomial $ R_Z(x) $ of $ 1/\\sqrt{x} $ for $ x \\in\n[1, \\lambda_{max}^2/\\lambda_{min}^2] $, with degrees $ (n-1,n) $ for $ N_s = 2n\n$, and $ (n,n) $ for $ N_s = 2 n + 1 $.",
        "positive": "Chiral Perturbation Theory on the Lattice; Strong Coupling Expansion: We evaluate the coefficients of the effective chiral Lagrangian to $O(p^4)$\nin the strong coupling, large-N expansion. In this limit we explicitly perform\nthe functional integral over fundamental degrees of freedom and obtain the\neffective chiral Lagrangian. We perform this calculation on the Body Centered\nHypercubical lattice which preserves Euclidean invariance to order $p^4$. We\nfurther discuss how the coefficients could be obtained numerically, out of the\nstrong-coupling domain."
    },
    {
        "anchor": "Heavy-light mesons in the epsilon-regime: We study the finite-size scaling of heavy-light mesons in the static limit.\nWe compute two-point functions of chiral current densities as well as\npseudoscalar densities in the epsilon-regime of heavy meson Chiral Perturbation\nTheory (HMChPT). As expected, finite volume dependence turns out to be\nsignificant in this regime and can be predicted in the effective theory in\nterms of the infinite-volume low-energy couplings. These results might be\nrelevant for extraction of heavy-meson properties from lattice simulations.",
        "positive": "Status of center dominance in various center gauges: We review arguments for center dominance in center gauges where vortex\nlocations are correctly identified. We introduce an appealing interpretation of\nthe maximal center gauge, discuss problems with Gribov copies, and a cure to\nthe problems through the direct Laplacian center gauge. We study correlations\nbetween direct and indirect Laplacian center gauges."
    },
    {
        "anchor": "B meson decay constant from two-flavor lattice QCD with non-relativistic\n  heavy quarks: We present a study of leptonic $B$ meson decay constants in lattice QCD with\ntwo flavors ($N_f=2$) of light dynamical quarks using NRQCD for the heavy\nquark. Gauge configurations are generated with a renormalization-group improved\ngauge action and a meanfield-improved clover light quark action. Measurements\nare carried out at two values of $\\beta=6/g^2$, each for four sea quark masses,\ncorresponding to the inverse lattice spacing $a^{-1}\\approx 1.3$ and 1.8 GeV in\nthe chiral limit of sea quark. The continuum values of the decay constants are\nderived by evaluating the discretization errors at each finite lattice spacing.\nWe find $f_B^{N_f=2}=204(8)(29)(+44) $ MeV, $f_{B_s}^{N_f=2} = 242(9)(34)(+38)$\nMeV, and $f_{B_s}^{N_f=2}/f_B^{N_f=2} = 1.179(18)(23)$, where the errors listed\nare statistical, systematic and uncertainty due to choice of the physical\nquantity used to fix the scale. Comparison is made to quenched results\n($N_f=0$) obtained with the same action combination and matching lattice\nspacings. We find $f_B^{N_f=2}/f_B^{N_f=0}=1.07(5)$,\n$f_{B_s}^{N_f=2}/f_{B_s}^{N_f=0}=1.10(5)$ and\n$(f_{B_s}/f_B)^{N_f=2}/(f_{B_s}/f_B)^{N_f=0}=1.03(2)$, which indicates a 5--10%\nincrease in the values of the decay constants, but no appreciable change in the\nratio $f_{B_s}/f_B$, due to sea quarks.",
        "positive": "Phase structure and critical temperature of two-flavor QCD with a\n  renormalization group improved gauge action and clover improved Wilson quark\n  action: We study the finite-temperature phase structure and the transition\ntemperature of QCD with two flavors of dynamical quarks on a lattice with the\ntemporal size $N_t=4$, using a renormalization group improved gauge action and\nthe Wilson quark action improved by the clover term. The region of a\nparity-broken phase is identified, and the finite-temperature transition line\nis located on a two-dimensional parameter space of the coupling ($\\beta=6/g^2$)\nand hopping parameter $K$. Near the chiral transition point, defined as the\ncrossing point of the critical line of the vanishing pion mass and the line of\nfinite-temperature transition, the system exhibits behavior well described by\nthe scaling exponents of the three-dimensional O(4) spin model. This indicates\na second-order chiral transition in the continuum limit. The transition\ntemperature in the chiral limit is estimated to be $T_c = 171(4)$ MeV."
    },
    {
        "anchor": "Hadronic vacuum polarization using gradient flow: The gradient-flow operator product expansion for QCD current correlators\nincluding operators up to mass dimension four is calculated through NNLO. This\npaves an alternative way for efficient lattice evaluations of hadronic vacuum\npolarization functions. In addition, flow-time evolution equations for flowed\ncomposite operators are derived. Their explicit form for the non-trivial\ndimension-four operators of QCD is given through order $\\alpha_s^3$.",
        "positive": "Physics issues in simulations with dynamical overlap fermions: We discuss the impact of various improvements on simulations of dynamical\noverlap fermions using the Hybrid Monte Carlo algorithm. We focus on the usage\nof fat links and multiple pseudo-fermion fields."
    },
    {
        "anchor": "Across the deconfinement: The deconfinement transition at vanishing chemical potential can be reliably\nstudied by lattice simulations and its general features are by now well known.\nOn the contrary, what happens at finite density is still largely unknown and we\nwill review the results obtained in the last year regarding the dependence, for\nsmall density, of the (pseudo)critical temperature on the baryonic chemical\npotential.",
        "positive": "Critical behavior of strongly coupled lattice QCD at finite temperature: We study the critical behavior of lattice Quantum Chromodynamics (QCD) in the\nstrong coupling approximation with Kogut-Susskind and Wilson fermions at finite\ntemperature ($T$) and zero chemical potential. Using the Hamiltonian\nformulation we construct a mean field solution to the equation of motion at\nfinite $T$ and use it to study the elementary thermal excitations and to\nextract some critical exponents characterizing the observed second order phase\ntransition. We find similar critical behaviors for Kogut-Susskind and Wilson\nfermions at finite $T$"
    },
    {
        "anchor": "Numerical Stochastic Perturbation Theory for full QCD: We give a full account of the Numerical Stochastic Perturbation Theory method\nfor Lattice Gauge Theories. Particular relevance is given to the inclusion of\ndynamical fermions, which turns out to be surprisingly cheap in this context.\nWe analyse the underlying stochastic process and discuss the convergence\nproperties. We perform some benchmark calculations and - as a byproduct - we\npresent original results for Wilson loops and the 3-loop critical mass for\nWilson fermions.",
        "positive": "Nucleon and Delta masses in twisted mass chiral perturbation theory: We calculate the masses of the nucleons and deltas in twisted mass heavy\nbaryon chiral perturbation theory. We work to quadratic order in a power\ncounting scheme in which we treat the lattice spacing and the quark masses to\nbe of the same order. We give expressions for the mass and the mass splitting\nof the nucleons and deltas both in and away from the isospin limit. We give an\nargument using the chiral Lagrangian treatment that, in the strong isospin\nlimit, the nucleons remain degenerate and the delta multiplet breaks into two\ndegenerate pairs to all orders in chiral perturbation theory. We show that the\nmass splitting between the degenerate pairs of the deltas first appears at\nquadratic order in in the lattice spacing. We discuss the subtleties in the\neffective chiral theory that arise from the inclusion of isospin breaking."
    },
    {
        "anchor": "D meson semileptonic form factors in Nf=3 QCD with M\u00f6bius domain-wall\n  quarks: We present our calculation of D \\to pi and D \\to K semileptonic form factors\nin Nf = 2+1 lattice QCD. We simulate three lattice cutoffs 1/a \\sim 2.5, 3.6\nand 4.5 GeV with pion masses as low as 230 MeV. The M\\\"obius domain-wall action\nis employed for both light and charm quarks. We present our results for the\nvector and scalar form factors and discuss their dependence on the lattice\nspacing, light quark masses and momentum transfer.",
        "positive": "Toward quantum computations of the $O(3)$ model using qumodes: We express the discrete 1+1-dimensional $O(3)$ non-linear sigma model\n(NL$\\sigma$M) in a form well-suited for the continuous variable approach to\nquantum computing. Within the Schwinger boson formulation, we need two qumodes\n(quantum-mechanical oscillators) at each lattice site. We envision that it\nmight be possible to reach the scaling regime of this model and observe\nasymptotic freedom on near-term photonic quantum devices in the coming decade."
    },
    {
        "anchor": "Adaptive Aggregation Based Domain Decomposition Multigrid for the\n  Lattice Wilson Dirac Operator: In lattice QCD computations a substantial amount of work is spent in solving\ndiscretized versions of the Dirac equation. Conventional Krylov solvers show\ncritical slowing down for large system sizes and physically interesting\nparameter regions. We present a domain decomposition adaptive algebraic\nmultigrid method used as a precondtioner to solve the \"clover improved\" Wilson\ndiscretization of the Dirac equation. This approach combines and improves two\napproaches, namely domain decomposition and adaptive algebraic multigrid, that\nhave been used seperately in lattice QCD before. We show in extensive numerical\ntest conducted with a parallel production code implementation that considerable\nspeed-up over conventional Krylov subspace methods, domain decomposition\nmethods and other hierarchical approaches for realistic system sizes can be\nachieved.",
        "positive": "SU(2) vortex configuration in Laplacian Center Gauge: We study how Laplacian Center Gauge identifies the vortex content of a thick\nSU(2) vortex configuration on the lattice. This configuration is a solution of\nthe Yang-Mills classical equations of motion having vortex properties. We find\nthat this gauge fixing procedure cleanly identifies the underlying vortex\nproperties. We also study the monopole content of this configuration detected\nwith this procedure. We obtain two monopole curves lying on the surface of the\nvortex."
    },
    {
        "anchor": "Complex Langevin Simulation of a Random Matrix Model at Nonzero Chemical\n  Potential: In this paper we test the complex Langevin algorithm for numerical\nsimulations of a random matrix model of QCD with a first order phase transition\nto a phase of finite baryon density. We observe that a naive implementation of\nthe algorithm leads to phase quenched results, which were also derived\nanalytically in this article. We test several fixes for the convergence issues\nof the algorithm, in particular the method of gauge cooling, the shifted\nrepresentation, the deformation technique and reweighted complex Langevin, but\nonly the latter method reproduces the correct analytical results in the region\nwhere the quark mass is inside the domain of the eigenvalues. In order to shed\nmore light on the issues of the methods we also apply them to a similar random\nmatrix model with a milder sign problem and no phase transition, and in that\ncase gauge cooling cooling solves the convergence problems as was shown before\nin the literature.",
        "positive": "Gluon Propagators and Confinement: We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at\nbeta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16\n(deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to\navoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon\npropagators show quite different behavior from those of massless gauge fields:\n(1) In the confinement phase, G(t) shows massless behavior at small and large\nt, while around 5<t<15 it behaves as massive particle, and (2) effective mass\nobserved in G(z) becomes larger as z increases. (3) In the deconfinement phase,\nG(z) shows also massive behavior but effective mass is less than in the\nconfinement case. In all cases, slope masses are increasing functions of t or\nz, which can not be understood as addtional physical poles."
    },
    {
        "anchor": "On the analytic continuation of the critical line: We perform a numerical study of the systematic effects involved in the\ndetermination of the critical line at real baryon chemical potential by\nanalytic continuation from results obtained at imaginary chemical potentials.\nWe present results obtained in a theory free of the sign problem, three-color\nQCD with finite isospin chemical potential, and comment on general features\nwhich could be relevant also to the continuation of the critical line in real\nQCD at finite baryon density.",
        "positive": "Lattice QCD at Finite Temperature: I review recent progress in lattice QCD at finite temperature. Results on the\ntransition temperature will be summarized. Recent progress in understanding\nin-medium modifications of interquark forces and quarkonia spectral functions\nat finite temperatures is discussed."
    },
    {
        "anchor": "Spectral quantities in thermal QCD: a progress report from the FASTSUM\n  collaboration: In order to study spectral quantities in thermal QCD, the FASTSUM\ncollaboration employs anisotropic lattice simulations with N_f=2+1 flavours of\nWilson fermions. Here we discuss our Generation 2 and Generation 2L ensembles,\nwhich differ in the pion mass. The focus is on observables related to the light\nquarks and chiral symmetry restoration.",
        "positive": "Two-nucleon S-wave interactions at the $SU(3)$ flavor-symmetric point\n  with $m_{ud}\\simeq m_s^{\\rm phys}$: a first lattice QCD calculation with the\n  stochastic Laplacian Heaviside method: We report on the first application of the stochastic Laplacian Heaviside\nmethod for computing multi-particle interactions with lattice QCD to the\ntwo-nucleon system. Like the Laplacian Heaviside method, this method allows for\nthe construction of interpolating operators which can be used to construct a\npositive definite set of two-nucleon correlation functions, unlike nearly all\nother applications of lattice QCD to two nucleons in the literature. It also\nallows for a variational analysis in which optimal linear combinations of the\ninterpolating operators are formed that couple predominantly to the eigenstates\nof the system. Utilizing such methods has become of paramount importance in\norder to help resolve the discrepancy in the literature on whether two nucleons\nin either isospin channel form a bound state at pion masses heavier than\nphysical, with the discrepancy persisting even in the $SU(3)$-flavor symmetric\npoint with all quark masses near the physical strange quark mass. This is the\nfirst in a series of papers aimed at resolving this discrepancy. In the present\nwork, we employ the stochastic Laplacian Heaviside method without a hexaquark\noperator in the basis at a lattice spacing of $a\\sim0.086$~fm, lattice volume\nof $L=48a\\simeq4.1$~fm and pion mass $m_\\pi\\simeq714$ MeV. With this setup, the\nobserved spectrum of two-nucleon energy levels strongly disfavors the presence\nof a bound state in either the deuteron or dineutron channel."
    },
    {
        "anchor": "Spontaneous supersymmetry breaking in two dimensional lattice super QCD: We report on a non-perturbative study of two dimensional $\\cN=(2,2)$ super\nQCD. Our lattice formulation retains a single exact supersymmetry at non-zero\nlattice spacing, and contains $N_f$ fermions in the fundamental representation\nof a $U(N_c)$ gauge group. The lattice action we employ contains an additional\nFayet-Iliopoulos term which is also invariant under the exact lattice\nsupersymmetry. This work constitutes the first numerical study of this theory\nwhich serves as a toy model for understanding some of the issues that are\nexpected to arise in four dimensional super QCD. We present evidence that the\nexact supersymmetry breaks spontaneously when $N_f<N_c$ in agreement with\ntheoretical expectations.",
        "positive": "More on the three-gluon vertex in SU(2) Yang-Mills theory in three and\n  four dimensions: The three-gluon vertex has been found to be a vital ingredient in\nnon-perturbative functional approaches. We present an updated lattice\ncalculation of it in various kinematical configurations for all tensor\nstructures and multiple lattice parameters in three dimensions, and in a subset\nof those in four dimensions, for SU(2) Yang-Mills theory in minimal Landau\ngauge. In three dimensions an unambiguous zero crossing for the tree-level\nform-factor is established, and consistency for all investigated form factors\nwith a power-like divergence towards the infrared is observed. Using very\ncoarse lattices this is even seen towards momenta as low as about 15 MeV. The\nresults in four dimensions are consistent with such a behavior, but do not yet\nreach deep enough into the infrared to establish it."
    },
    {
        "anchor": "Combined Relativistic and static analysis for all Delta B=2 operators: We analyse matrix elements of Delta B=2 operators by combining QCD results\nwith the ones obtained in the static limit of HQET. The matching of all the QCD\noperators to HQET is made at NLO order. To do that we have to include the\nanomalous dimension matrix up to two loops, both in QCD and HQET, and the one\nloop matching for all the Delta B=2 operators. The matrix elements of these\noperators are relevant for the prediction of the B-\\bar B mixing, B_s meson\nwidth difference and supersymmetric effects in Delta B=2 transitions.",
        "positive": "The Drell-Yan process and Deep Inelastic Scattering from the lattice: We report on measurements of the h_1 structure function, relevant to\ncalculating cross-sections for the Drell-Yan process. This is a quantity which\ncan not be measured in Deep Inelastic Scattering, it gives additional\ninformation on the spin carried by the valence quarks, as well as insights on\nhow relativistic the quarks are."
    },
    {
        "anchor": "Center vortices and Dirac eigenmodes in SU(2) lattice gauge theory: We study the interplay between Dirac eigenmodes and center vortices in SU(2)\nlattice gauge theory. In particular we focus on vortex-removed configurations\nand compare them to an ensemble of configurations with random changes of the\nlink variables. We show that removing the vortices destroys all zero modes and\nthe near zero modes are no longer coupled to topological structures. The Dirac\nspectrum for vortex-removed configurations in many respects resembles a free\nspectrum thus leading to a vanishing chiral condensate. Configurations with\nrandom changes leave the topological features of the Dirac eigensystem intact.\nWe finally show that smooth center vortex configurations give rise to zero\nmodes and topological near zero modes.",
        "positive": "Phase structure for lattice fermions with flavored chemical potential\n  terms: We discuss the chiral phase diagram in the parameter space of lattice QCD\nwith minimal-doubling fermions, which can be seen as lattice fermions with\nflavored chemical potential terms. We study strong-coupling lattice QCD with\nthe Karsten-Wilczek formulation, which has one relevant parameter $\\mu_{3}$ as\nwell as gauge coupling and a mass parameter. We find a nontrivial chiral phase\nstructure with a second-order phase transition between chiral symmetric and\nbroken phases. To capture the whole structure of the phase diagram, we study\nthe related lattice Gross-Neveu model. The result indicates that the chiral\nphase transition also exists in the weak-coupling region. From these results we\nspeculate on the $\\mu_{3}$-$g^{2}$ chiral phase diagram in lattice QCD with\nminimal-doubling fermions, and discuss their application to numerical\nsimulations."
    },
    {
        "anchor": "Pathological Behavior of Renormalization-Group Maps at High Fields and\n  Above the Transition Temperature: We show that decimation transformations applied to high-$q$ Potts models\nresult in non-Gibbsian measures even for temperatures higher than the\ntransition temperature. We also show that majority transformations applied to\nthe Ising model in a very strong field at low temperatures produce non-Gibbsian\nmeasures. This shows that pathological behavior of renormalization-group\ntransformations is even more widespread than previous examples already\nsuggested.",
        "positive": "Diquark Condensation at Nonzero Chemical Potential and Temperature: SU(2) lattice gauge theory with four flavors of quarks is studied at nonzero\nchemical potential $\\mu$ and temperature $T$ by computer simulation and\nEffective Lagrangian techniques. Simulations are done on $8^4$, $8^3 \\times 4$\nand $12^3 \\times 6$ lattices and the diquark condensate, chiral order\nparameter, Wilson line, fermion energy and number densities are measured.\nSimulations at a fixed, nonzero quark mass provide evidence for a tricritical\npoint in the $\\mu$-$T$ plane associated with diquark condensation. For low $T$,\nincreasing $\\mu$ takes the system through a line of second order phase\ntransitions to a diquark condensed phase. Increasing $T$ at high $\\mu$, the\nsystem passes through a line of first order transitions from the diquark phase\nto the quark-gluon plasma phase. Using Effective Lagrangians we estimate the\nposition of the tricritical point and ascribe its existence to trilinear\ncouplings that increase with $\\mu$ and $T$."
    },
    {
        "anchor": "Recycle of random sequences: The correlation between a random sequence and its transformed sequences is\nstudied. In the case of a permutation operation or, in other word, the\nshuffling operation, it is shown that the correlation can be so small that the\nsequences can be regarded as independent random sequences. The applications to\nthe Monte Carlo simulations are also given. This method is especially useful in\nthe Ising Monte Carlo simulation.",
        "positive": "Role of the strange quark in the rho(770) meson: Recently, the GWU lattice group has evaluated high-precision phase-shift data\nfor $\\pi\\pi$ scattering in the $I = 1$, $J = 1$ channel. Unitary Chiral\nPerturbation Theory describes these data well around the resonance region and\nfor different pion masses. Moreover, it allows to extrapolate to the physical\npoint and estimate the effect of the missing $K\\bar{K}$ channel in the\ntwo-flavor lattice calculation. The absence of the strange quark in the lattice\ndata leads to a lower $\\rho$ mass, and the analysis with U$\\chi$PT shows that\nthe $K \\bar{K}$ channel indeed pushes the $\\pi\\pi$-scattering phase shift\nupward, having a surprisingly large effect on the $\\rho$-mass. The inelasticity\nis shown to be compatible with the experimental data. The analysis is then\nextended to all available two-flavor lattice simulations and similar mass\nshifts are observed. Chiral extrapolations of $N_f = 2 + 1$ lattice simulations\nfor the $\\rho(770)$ are also reported."
    },
    {
        "anchor": "Melting of P wave bottomonium states in the quark-gluon plasma from\n  lattice NRQCD: We study the fate of P wave bottomonium states in the quark-gluon plasma,\nusing a spectral function analysis of euclidean lattice correlators. The\ncorrelators are obtained from lattice QCD simulations with two light quark\nflavours on highly anisotropic lattices, treating the bottom quark\nnonrelativistically. We find clear indications of melting immediately after the\ndeconfinement transition.",
        "positive": "Radial Excited States for Heavy Quark Systems in NRQCD: Following the Non-Relativistic QCD approach we use a gauge invariant smearing\nmethod with factorization to measure the excitation energies for a heavy\n$Q\\bar{Q}$ system on a $24^3\\times 48$ lattice at $\\beta=6.2$. The results come\nfrom averaging over an ensemble of 60 QCD configurations. In order to enhance\nthe signal from each configuration we use wall sources for quark propagators.\nThe quark Hamiltonian contains only the simplest non-relativistic kinetic\nenergy term. The results are listed for a range of bare quark masses. The mass\nsplittings are insensitive to this variable though there are a slight trends\nwith increasing quark mass. For an appropriate choice of UV cut-off\n($a^{-1}=3.2$Gev) the mass spectrum compares reasonably well with the\nexperimental values for the spin-averaged energy gaps of the $\\Upsilon$ system.\nWe also present results for the $DE$ and $DT$ waves for the lowest bare quark\nmass. The results are consistent with degeneracy between the two types of $D$\nwave. This encourages the idea that even with our simple quark Hamiltonian the\ndeparture from rotational invariance is not great."
    },
    {
        "anchor": "Aspects of finite temperature QCD towards the chiral limit: QCD under extreme conditions has been studied for a long time, and the chiral\nlimit has been a grey area mostly. In this write-up of my talk, I review some\nof the recent developments made by the community to unveil various features of\nQCD towards the chiral limit, which includes calculation of the chiral critical\ntemperature and determination of the order of chiral phase transition for\nvarious numbers of flavors. Acknowledging the importance of the studies\nregarding the effective restoration of $U_A(1)$, I try to give a comprehensive\noverview about the various studies done in the last few years in a comparative\nmanner to realize the current status of the community in this regard. I also\ndiscuss very recent efforts about the relevance of various energy-like\nobservables w.r.t. the chiral phase transition.",
        "positive": "Geometrical aspects of chiral anomalies in the overlap: The set of one dimensional lowest energy eigenspaces used to construct the\noverlap induces a two form on gauge orbit space which is the locally exact curl\nof Berry's connection. If anomalies do not cancel, examples of two dimensional\nclosed sub-manifolds of orbit space are produced over which the integral of the\nabove two form does not vanish. Based on these observations, a natural\ndefinition of covariant currents is obtained, a simple way to calculate chiral\nanomalies on the lattice is found, and indications for how to construct an\nideal regularization of chiral gauge theories are seen to emerge."
    },
    {
        "anchor": "Plane vortex pairs, colorful structures and low-lying Dirac modes: We investigate the influence of topological charges on non-stable zero and\nnear-zero modes of the single uni-color plane vortex pairs. We combine the\nuni-color plane vortices with the spherical vortex and also construct the plane\nvortex pairs with two colorful vortices. The stability of zero and near-zero\nmodes is analyzed where various boundary conditions for the fermions are\nchecked. In addition, plane vortex pairs may show the role of the topological\ncharges for changing the chirality of fermions. The results clearly indicate\ncharacteristic properties for spontaneous chiral symmetry breaking.",
        "positive": "Exponential reduction of finite volume effects with twisted boundary\n  conditions: Flavor-twisted boundary conditions can be used for exponential reduction of\nfinite volume artifacts in flavor-averaged observables in lattice QCD\ncalculations with $SU(N_f)$ light quark flavor symmetry. Finite volume artifact\nreduction arises from destructive interference effects in a manner closely\nrelated to the phase averaging which leads to large $N_c$ volume independence.\nWith a particular choice of flavor-twisted boundary conditions, finite volume\nartifacts for flavor-singlet observables in a hypercubic spacetime volume are\nreduced to the size of finite volume artifacts in a spacetime volume with\nperiodic boundary conditions that is four times larger."
    },
    {
        "anchor": "The Isgur-Wise Function: A Lattice Determination from Pseudoscalar -->\n  Pseudoscalar Form Factors: Form factors for pseudoscalar --> pseudoscalar decays of heavy-light mesons\nare found in quenched lattice QCD with heavy-quark masses in the range of\napproximately 1-2 GeV. The Isgur-Wise function, $\\xi(\\omega)$, is extracted\nfrom these form factors. Results are in good agreement with $\\xi(\\omega)$\nderived from CLEO measurements for B --> D*.",
        "positive": "\u0394S=2 and \u0394C=2 bag parameters in the SM and beyond from\n  Nf=2+1+1 twisted-mass LQCD: We present unquenched lattice QCD results for the matrix elements of\nfour-fermion operators relevant to the description of the neutral K and D\nmixing in the Standard Model and its extensions. We have employed simulations\nwith Nf = 2 + 1 + 1 dynamical sea quarks at three values of the lattice\nspacings in the interval 0.06 - 0.09 fm and pseudoscalar meson masses in the\nrange 210 - 450 MeV. Our results are extrapolated to the continuum limit and to\nthe physical pion mass. Renormalization constants have been determined\nnon-perturbatively in the RI-MOM scheme. In particular, for the Kaon\nbag-parameter, which is relevant for the \\overline{K}^0-K^0 mixing in the\nStandard Model, we obtain B_K^{RGI} = 0.717(24)."
    },
    {
        "anchor": "Wilson fermions at fine lattice spacings: scale setting, pion form\n  factors and (g-2)_mu: We present an update on our on-going project to compute hadronic observables\nfor Nf=2 flavours of O(a) improved Wilson fermions at small lattice spacings.\nThe procedure to determine the lattice scale via the mass of the Omega baryon\nis described. Furthermore we present preliminary results for the pion form\nfactor computed using twisted boundary conditions, and report on the\nimplementation of a novel approach to determine the contribution of the\nhadronic vacuum polarisation to the anomalous magnetic moment of the muon.",
        "positive": "NSPT study of the three-loop lattice gluon propagator in Landau gauge: By means of Numerical Stochastic Perturbation Theory (NSPT), we calculate the\nlattice gluon propagator up to three loops of perturbation theory in the limits\nof infinite volume and vanishing lattice spacing. Based on known anomalous\ndimensions and a parametrization of both the hypercubic symmetry group H(4) and\nfinite-size effects, we calculate the non-leading-log and non-logarithmic\ncontributions iteratively, starting with the first-loop expression."
    },
    {
        "anchor": "Dynamical fermion algorithm for variable actions: A new version of the two-step multi-boson algorithm is developed with\ndifferent fermion actions in the multi-boson and noisy Metropolis steps.",
        "positive": "Strong Coupling Expansion for Scattering Phases in Hamiltonian Lattice\n  Field Theories - I. the $(d+1)$-dimensional Ising model: A systematic method to obtain strong coupling expansions for scattering\nquantities in Hamiltonian lattice field theories is presented. I develop the\nconceptual ideas by means of the Hamiltonian field theory analogue of the Ising\nmodel, in $d$ space and one time dimension. The main result is a convergent\nseries representation for the sacttering states and the transition matrix. To\nbe explicit the special cases of $d=1$ and $d=3$ spatial dimensions are\ndiscussed in detail. I compute the next-to-leading order approximation for the\nphase shifts. The application of the method to investigate low-energy\nscattering phenomena in lattice gauge theory and QCD is proposed."
    },
    {
        "anchor": "Understanding the U(1) problem through dyon configuration in the Abelian\n  projection: We give a short review of the recently obtained result that the magnetic\nmonopole promoted to the dyon due to the vacuum angle $\\theta$ resolves the\nU(1) problem in the sense that the dyon obtained in this way gives a dominant\ncontribution to the topological susceptibility",
        "positive": "Single flavor staggered fermions: Based on recent work by Adams, I construct a lattice fermion operator that\nfully lifts the staggered flavor degeneracy. The resulting operator is of\nWilson type but smaller by a factor of 4, better conditioned and contains 3\ninstead of 15 doublers. It is further suggested that this operator may be used\nas a candidate kernel operator to an overlap construction. Prospects for\npractical applications and potential problems of the new discretizations are\nbriefly discussed."
    },
    {
        "anchor": "Determination of Vus: Recent Input from the Lattice: The two most precise determinations of the CKM matrix element V_us are based\non the analyses of leptonic and semileptonic kaon decays. These studies also\nrely on the lattice QCD calculations of two hadronic parameters, namely the\nratio of the kaon and pion decay constants, f_K+/f_pi+, and the kaon\nsemileptonic vector form factor at zero momentum transfer, f_+(0). In this\ntalk, I review the recent lattice results for these quantities, by showing that\nthe sub-percent accuracy required by the phenomenological analyses has been\nreached by lattice QCD. As best estimates of the lattice calculations I quote\nf_K+/f_pi+ = 1.193(4) and f_+(0)=0.965(3). I also discuss some recent\ntheoretical progress in the evaluation of the small, but phenomenologically\nrelevant, SU(2) isospin breaking corrections.",
        "positive": "Non-perturbative calculation of $Z_V$ and $Z_A$ in domain-wall QCD on a\n  finite box: We report on a non-perturbative evaluation of the renormalization factors for\nthe vector and axial-vector currents, $Z_V$ and $Z_A$, in the quenched\ndomain-wall QCD (DWQCD) with plaquette and renormalization group improved gauge\nactions. We take the Dirichlet boundary condition for both gauge and\ndomain-wall fermion fields on the finite box, and introduce the flavor-chiral\nWard-Takahashi identities to calculate the renormalization factors. As a test\nof the method, we numerically confirm the expected relation that $Z_V \\simeq\nZ_A$ in DWQCD. Employing two different box sizes for the numerical simulations\nat several values of the gauge coupling constant $g^2$ and the domain-wall\nheight $M$, we extrapolate $Z_V$ to the infinite volume to remove $a/L$ errors.\nWe finally give the interpolation formula of $Z_V$ in the infinite volume as a\nfunction of $g^2$ and $M$."
    },
    {
        "anchor": "Spectral Density Study of the SU(3) Deconfining Phase Transition: We present spectral density reweighting techniques adapted to the analysis of\na time series of data with a continuous range of allowed values. In a first\napplication we analyze action and Polyakov line data from a Monte Carlo\nsimulation on $L_t L^3 (L_t=2,4)$ lattices for the SU(3) deconfining phase\ntransition. We calculate partition function zeros, as well as maxima of the\nspecific heat and of the order parameter susceptibility. Details and warnings\nare given concerning i) autocorrelations in computer time and ii) a reliable\nextraction of partition function zeros. The finite size scaling analysis of\nthese data leads to precise results for the critical couplings $\\beta_c$, for\nthe critical exponent $\\nu$ and for the latent heat $\\triangle s$. In both\ncases ($L_t=2$ and 4), the first order nature of the transition is\nsubstantiated.",
        "positive": "Zeros of the Partition Function for Higher--Spin 2D Ising Models: We present calculations of the complex-temperature zeros of the partition\nfunctions for 2D Ising models on the square lattice with spin $s=1$, 3/2, and\n2. These give insight into complex-temperature phase diagrams of these models\nin the thermodynamic limit. Support is adduced for a conjecture that all\ndivergences of the magnetisation occur at endpoints of arcs of zeros protruding\ninto the FM phase. We conjecture that there are $4[s^2]-2$ such arcs for $s \\ge\n1$, where $[x]$ denotes the integral part of $x$."
    },
    {
        "anchor": "Non-perturbative evaluation for anomalous dimension in 2-dimensional\n  O(3) sigma model: We calculate the wave-function renormalization in 2-dimensional O(3) sigma\nmodel, non- perturbatively. It is evaluated in a box with a finite spatial\nextent. We determine the anomalous dimension in the finite volume scheme\nthrough an analysis of the step scaling function. Results are compared with a\nperturbative evaluation, and the reasonable behavior is confirmed.",
        "positive": "Optimization of Lattice QCD codes for the AMD Opteron processor: We report our experience of the optimization of the lattice QCD codes for the\nnew Opteron cluster at DESY Hamburg, including benchmarks. Details of the\noptimization using SSE/SSE2 instructions and the effective use of prefetch\ninstructions are discussed."
    },
    {
        "anchor": "Relating the finite-volume spectrum and the two-and-three-particle $S$\n  matrix for relativistic systems of identical scalar particles: Working in relativistic quantum field theory, we derive the quantization\ncondition satisfied by coupled two- and three-particle systems of identical\nscalar particles confined to a cubic spatial volume with periodicity $L$. This\ngives the relation between the finite-volume spectrum and the infinite-volume\n$\\textbf 2 \\to \\textbf 2$, $\\textbf 2 \\to \\textbf 3$ and $\\textbf 3 \\to \\textbf\n3$ scattering amplitudes for such theories. The result holds for relativistic\nsystems composed of scalar particles with nonzero mass $m$, whose center of\nmass energy lies below the four-particle threshold, and for which the\ntwo-particle $K$ matrix has no singularities below the three-particle\nthreshold. The quantization condition is exact up to corrections of the order\n$\\mathcal{O}(e^{-mL})$ and holds for any choice of total momenta satisfying the\nboundary conditions.",
        "positive": "The QCD sign problem as a total derivative: We consider the distribution of the complex phase of the fermion determinant\nin QCD at nonzero chemical potential and examine the physical conditions under\nwhich the distribution takes a Gaussian form. We then calculate the baryon\nnumber as a function of the complex phase of the fermion determinant and show\n1) that the exponential cancellations produced by the sign problem take the\nform of total derivatives 2) that the full baryon number is orthogonal to this\nnoise. These insights allow us to define a self-consistency requirement for\nmeasurements of the baryon number in lattice simulations."
    },
    {
        "anchor": "Second order cumulants of conserved charge fluctuations revisited I.\n  Vanishing chemical potentials: We update lattice QCD results for second order cumulants of conserved charge\nfluctuations and correlations at non-zero temperature and vanishing values of\nthe conserved charge chemical potentials. We compare these results to hadron\nresonance gas calculations with and without excluded volume terms as well as\nS-matrix results in the hadronic phase of QCD, and comment on their current\nlimitations. We, furthermore, use these results to characterize thermal\nconditions in the vicinity of the pseudo-critical line of the chiral transition\nin QCD. We argue that the ratio of strange to baryon chemical potentials is a\nrobust observable that, on the one hand, deviates only little from hadron\nresonance gas results, but, on the other hand, is very sensitive to the\nspectrum of strange baryon resonances.",
        "positive": "Recent results on the running coupling in QCD with two massless flavours: We report on the latest results on the running coupling of two flavour QCD in\nthe Schr\\\"odinger functional scheme. Results for the step scaling function are\nobtained from simulations on lattices $L/a=8$ and $L/a=16$ which confirm the\nfirst results from lattices $L/a=4,5,6$ presented one year ago by the ALPHA\ncollaboration. We also discuss some algorithmic aspects, in particular\nconcerning the occurrence of metastable states. A modified sampling, in order\nto estimate the proper weight of these states in the path integral, is proposed\nand tested."
    },
    {
        "anchor": "Higher order expansions for the entropy of a dimer or a monomer-dimer\n  system on d-dimensional lattices: Recently an expansion as a power series in 1/d has been presented for the\nspecific entropy of a complete dimer covering of a d-dimensional hypercubic\nlattice. This paper extends from 3 to 10 the number of terms known in the\nseries. Likewise an expansion for the entropy, dependent on the dimer-density\np, of a monomer-dimer system, involving a sum sum_k a_k(d) p^k, has been\nrecently offered. We herein extend the number of the known expansion\ncoefficients from 6 to 20 for the hyper-cubic lattices of general dimension d\nand from 6 to 24 for the hyper-cubic lattices of dimensions d < 5 . We show\nthat this extension can lead to accurate numerical estimates of the p-dependent\nentropy for lattices with dimension d > 2. The computations of this paper have\nled us to make the following marvelous conjecture: \"In the case of the\nhyper-cubic lattices, all the expansion coefficients, a_k(d), are positive\"!\nThis paper results from a simple melding of two disparate research programs:\none computing to high orders the Mayer series coefficients of a dimer gas, the\nother studying the development of entropy from these coefficients. An effort is\nmade to make this paper self-contained by including a review of the earlier\nworks.",
        "positive": "The quark-mass dependence of the potential energy between static colour\n  sources in the QCD vacuum with light and strange quarks: The low-lying energy spectrum of the static-colour-source-anti-source system\nin a vacuum containing light and strange quarks is computed using lattice QCD\nfor a range of different light quark masses. The resulting levels are described\nusing a simple model Hamiltonian and the parameters in this model are\nextrapolated to the physical light-quark masses. In this framework, the QCD\nstring tension is found to be $\\sqrt{\\sigma}=445(3)_{\\rm stat}(6)_{\\rm sys}$\nMeV."
    },
    {
        "anchor": "Excited-state energies and scattering phase shifts from lattice QCD with\n  the stochastic LapH method: Recent results in computing excited-state energies and meson-meson scattering\nphase shifts in lattice QCD are presented. A stochastic method of treating the\nlow-lying modes of quark propagation that exploits Laplacian Heaviside\nquark-field smearing makes such studies possible now on large 32^3 x 256 and\n48^3 x 128 lattices at near physical pion masses. Levels are identified using a\nvariety of probe interpolating operators, which include both single-hadron and\na large number of two-hadron operators.",
        "positive": "Visualisations of Centre Vortices: The centre vortex structure of the vacuum is visualised through the use of\nnovel 3D visualisation techniques. These visualisations allow for a hands-on\nexamination of the centre-vortex matter present in the QCD vacuum, and\nhighlights some of the key features of the centre-vortex model. The connection\nbetween topological charge and singular points is also explored. This work\nhighlights the useful role visualisations play in the exploration of the QCD\nvacuum."
    },
    {
        "anchor": "Light hadron spectrum with Kogut-Susskind quarks: We made an extensive study of the light hadron spectrum using the Wilson\ngauge action and Kogut-Susskind quarks. Using both dynamical quarks and the\nquenched approximation, we determine hadron masses for five and four gauge\ncouplings respectively, with at least five quark masses at each coupling. In\nthe continuum limit, we find a significant difference between two flavors of\ndynamical quarks and the quenched approximation for a range of quark masses.",
        "positive": "Better HMC integrators for dynamical simulations: We show how to improve the molecular dynamics step of Hybrid Monte Carlo,\nboth by tuning the integrator using Poisson brackets measurements and by the\nuse of force gradient integrators. We present results for moderate lattice\nsizes."
    },
    {
        "anchor": "Frequency-splitting estimators of single-propagator traces: Single-propagator traces are the most elementary fermion Wick contractions\nwhich occur in numerical lattice QCD, and are usually computed by introducing\nrandom-noise estimators to profit from volume averaging. The additional\ncontribution to the variance induced by the random noise is typically orders of\nmagnitude larger than the one due to the gauge field. We propose a new family\nof stochastic estimators of single-propagator traces built upon a frequency\nsplitting combined with a hopping expansion of the quark propagator, and test\ntheir efficiency in two-flavour QCD with pions as light as 190 MeV. Depending\non the fermion bilinear considered, the cost of computing these diagrams is\nreduced by one to two orders of magnitude or more with respect to standard\nrandom-noise estimators. As two concrete examples of physics applications, we\ncompute the disconnected contributions to correlation functions of two vector\ncurrents in the isosinglet omega channel and to the hadronic vacuum\npolarization relevant for the muon anomalous magnetic moment. In both cases,\nestimators with variances dominated by the gauge noise are computed with a\nmodest numerical effort. Theory suggests large gains for disconnected three and\nhigher point correlation functions as well. The frequency-splitting estimators\nand their split-even components are directly applicable to the newly proposed\nmulti-level integration in the presence of fermions.",
        "positive": "Realistic in-medium heavy-quark potential from high statistics lattice\n  QCD simulations: We present our first results on a direct computation of the complex in-medium\nheavy quark potential from realistic lattice QCD simulations. Ensembles with\n$N_\\tau=12$ from the HotQCD and TUMQCD collaboration offer unprecedented high\nstatistics, those with $N_\\tau=16$ unprecedented time resolution, making\npossible a robust extraction of the real part from the spectral functions of\nWilson line correlators. To this end we deploy a combination of a Bayesian\nreconstruction (BR method), as well as a Pad\\'e-like approximation. We\ncorroborate findings made on less realistic lattices that ${\\rm Re}[V]$\nsmoothly transitions from a confining to a screened behavior at high\ntemperatures and its values lie close to the color singlet free energies. A\nfinite value of the ${\\rm Im}[V]$ is observed in the quark-gluon-plasma phase."
    },
    {
        "anchor": "Non-perturbative states in the three-dimensional phi^4 theory: We study the spectrum of massive excitations of the three-dimensional phi^4\nand Ising models, in the broken-symmetry phase. Using a variational method, we\nshow that the spectrum contains all the 0+ states that one expects from duality\nwith the glueball spectrum of the Z(2) gauge model. From the point of view of\ncontinuum phi^4 theory, we show that at least one of the states we find has a\nnon-perturbative origin.",
        "positive": "Monopoles and Confining Strings in QCD: We review the recent results in the physics of the magnetic monopoles in\ngluodynamics and a dual formulation of non-Abelian theories, relevant to the\nphysics of the confinement. It occurs that the dual gluon is a U(1) gauge\nboson, despite of the fact that usual gluons are non-Abelian. The effective\ninfrared Lagrangian for gluodynamics is suggested which leads to the Casimir\nscaling of the string tension for quarks in various representations. We also\nshow that the results of the calculations in lattice gauge theories confirm our\ntheoretical predictions."
    },
    {
        "anchor": "Heavy Quark Diffusion and Lattice Correlators: We study charmonia correlators at finite temperature. We analyze to what\nextent heavy quarkonia correlators are sensitive to the effect of heavy quark\ntransport and whether it is possible to constrain the heavy quark diffusion\nconstant by lattice calculations. Preliminary lattice calculations of quarkonia\ncorrelators performed on anisotropic lattices show that they are sensitive to\nthe effect of heavy quark transport, but much detailed calculations are\nrequired to constrain the value of the heavy quark diffusion constant.",
        "positive": "Relativistic, model-independent, three-particle quantization condition: This is a combined write-up for two talks which were given consecutively and\nwhich described different aspects of the same topic. We present a\ngeneralization of L\\\"uscher's relation between the finite-volume spectrum and\nS-matrix to three particles. Specifically, we consider a scalar field theory,\nwhich has a $\\mathbb{Z}_2$ symmetry that prevents even/odd coupling. The theory\nis assumed to have no two-particle bound states and to have two-particle phase\nshifts that are bounded by $\\pi/2$ in the regime of elastic scattering.\nConsidering center of mass energies between one and five particle masses, we\nevaluate a three-to-three finite-volume correlator to all orders in\nperturbation theory. Only terms which are exponentially suppressed in volume\nare neglected. From poles in the correlator we then determine the relation\nbetween finite-volume spectrum and scattering quantities. In this analysis one\nmust carefully treat the unitary cusp at two-particle threshold. This point,\nwhich was neglected in the conference talks, is described in some detail here.\nWe also describe an important check on our main result by reproducing the large\nvolume expansion of the energy shift from the three-particle threshold. This is\nfound to be consistent with previous work through four non-trivial orders."
    },
    {
        "anchor": "Neutrinoless Double Beta Decay from Lattice QCD: The Long-Distance\n  $\u03c0^{-} \\rightarrow \u03c0^{+} e^{-} e^{-}$ Amplitude: Neutrinoless double beta decay (\\( 0 \\nu \\beta \\beta \\)) is a hypothetical\nnuclear decay mode with important implications. In particular, observation of\nthis decay would demonstrate that the neutrino is a Majorana particle and that\nlepton number conservation is violated in nature. Relating experimental\nconstraints on \\(0 \\nu \\beta \\beta\\) decay rates to the neutrino masses\nrequires theoretical input in the form of non-perturbative nuclear matrix\nelements which remain difficult to calculate reliably. This work marks a first\nstep toward providing a general lattice QCD framework for computing\nlong-distance \\(0 \\nu \\beta \\beta\\) matrix elements in the case where the decay\nis mediated by a light Majorana neutrino. The relevant formalism is developed\nand then tested by computing the simplest such matrix element describing an\nunphysical \\( \\pi^{-} \\rightarrow \\pi^{+} e^{-} e^{-} \\) transition on a series\nof domain wall fermion ensembles. The resulting lattice data is then fit to\nnext-to-leading-order chiral perturbation theory, allowing a fully-controlled\nextraction of the low energy constant governing the transition rate,\n\\(g_{\\nu}^{\\pi \\pi}(\\mu = 770 \\,\\, \\mathrm{MeV}) = -10.78(12)_{\\rm\nstat}(51)_{\\rm sys}\\). Finally, future prospects for calculations of more\ncomplicated processes, such as the phenomenologically important \\(n^{0} n^{0}\n\\rightarrow p^{+} p^{+} e^{-} e^{-}\\) decay, are discussed.",
        "positive": "An upper limit to the electric dipole moment of the neutron from lattice\n  QCD: A linear increase with the volume of the topological susceptibility can\nsignal spontaneous breaking of parity and time inversion, due to a nonzero\nvacuum expectation value of the topological charge. Such a breaking would\nproduce a nonzero electric dipole moment of the neutron, d_n. An upper limit to\nd_n is derived from numerical simulations at increasing volumes."
    },
    {
        "anchor": "Heavy Domain Wall Fermions: The RBC and UKQCD charm physics program: We review the domain wall charm physics program of the RBC and UKQCD\ncollaborations based on simulations including ensembles with physical pion\nmass. We summarise our current set-up and present a status update on the decay\nconstants $f_D$, $f_{D_s}$, the charm quark mass, heavy-light and heavy-strange\nbag parameters and the ratio $\\xi$.",
        "positive": "Quenched QCD with O(a) improvement: I. The spectrum of light hadrons: We present a comprehensive study of the masses of pseudoscalar and vector\nmesons, as well as octet and decuplet baryons computed in O(a) improved\nquenched lattice QCD. Results have been obtained using the non-perturbative\ndefinition of the improvement coefficient c_sw, and also its estimate in\ntadpole improved perturbation theory. We investigate effects of improvement on\nthe incidence of exceptional configurations, mass splittings and the parameter\nJ. By combining the results obtained using non-perturbative and tadpole\nimprovement in a simultaneous continuum extrapolation we can compare our\nspectral data to experiment. We confirm earlier findings by the CP-PACS\nCollaboration that the quenched light hadron spectrum agrees with experiment at\nthe 10% level."
    },
    {
        "anchor": "Odd-flavor Simulations by the Hybrid Monte Carlo: The standard hybrid Monte Carlo algorithm is known to simulate even flavors\nQCD only. Simulations of odd flavors QCD, however, can be also performed in the\nframework of the hybrid Monte Carlo algorithm where the inverse of the fermion\nmatrix is approximated by a polynomial. In this exploratory study we perform\nthree flavors QCD simulations. We make a comparison of the hybrid Monte Carlo\nalgorithm and the R-algorithm which also simulates odd flavors systems but has\nstep-size errors. We find that results from our hybrid Monte Carlo algorithm\nare in agreement with those from the R-algorithm obtained at very small\nstep-size.",
        "positive": "Topological charge density around static color sources: We analyze the topological structure of quenched QCD in the presence of\nstatic color sources. Distributions of the topological charge density around\nstatic quarks and mesons are computed in both phases of QCD. We observe a\nsuppression of topological fluctuations in the vicinity of external sources. In\nthe confinement phase, the suppression occurs in the whole flux tube between\nthe static quark and antiquark."
    },
    {
        "anchor": "Critical exponents and unusual properties of the broken phase in the\n  3d-RP(2) antiferromagnetic model: We present the results of a Monte Carlo simulation of the antiferromagnetic\nRP(2) model in three dimensions. With finite-size scaling techniques we\naccurately measure the critical exponents and compare them with those of O(N)\nmodels. We are able to parameterize the corrections-to-scaling. The symmetry\nproperties of the broken phase are also studied.",
        "positive": "The Staggered Eta-prime with Smeared Operators: We present a refined calculation of the eta-prime mass using staggered\nfermions and Wuppertal smeared operators. We use quenched and dynamical\nconfigurations of size 16^3x32 with Nf=0, Nf=2 and Nf=4, and compare our\nresults with the expected forms from quenched, partially quenched and\nunquenched chiral perturbation thoery."
    },
    {
        "anchor": "Semileptonic decay of a heavy-light pseudoscalar to a light vector meson: We present the results of a calculation of semileptonic form factors of D and\nB mesons. The calculation uses nonperturbatively order a improved quenched\nlattice QCD and two values of the coupling. Results for charm mesons show\nreasonable agreement with experiment. The lattice results for B -> rho l nu are\ncompared with high q^2 experimental results.",
        "positive": "Lattice QCD with a twisted mass term and a strange quark: There are three quarks with masses at or below the characteristic scale of\nQCD dynamics: up, down and strange. However, twisted mass lattice QCD relies on\nquark doublets. Various options for including three quark flavors within the\ntwisted mass approach are explored by studying the kaon masses, both\nanalytically (through chiral Lagrangians) and numerically (through lattice\nsimulations). Advantages and disadvantages are revealed for each ``strange and\ntwisted'' option."
    },
    {
        "anchor": "First lattice calculation of radiative leptonic decay rates of\n  pseudoscalar mesons: We present a non-perturbative lattice calculation of the form factors which\ncontribute to the amplitudes for the radiative decays $P\\to \\ell \\bar \\nu_\\ell\n\\gamma$, where $P$ is a pseudoscalar meson and $\\ell$ is a charged lepton.\nTogether with the non-perturbative determination of the corrections to the\nprocesses $P\\to \\ell \\bar \\nu_\\ell$ due to the exchange of a virtual photon,\nthis allows accurate predictions at $O(\\alpha_{em})$ to be made for leptonic\ndecay rates for pseudoscalar mesons ranging from the pion to the $D_s$ meson.\nWe are able to separate unambiguously and non-pertubatively the point-like\ncontribution, from the structure-dependent, infrared-safe, terms in the\namplitude. The fully non-perturbative $O(a)$ improved calculation of the\ninclusive leptonic decay rates will lead to the determination of the\ncorresponding Cabibbo-Kobayashi-Maskawa (CKM) matrix elements also at\n$O(\\alpha_{em})$. Prospects for a precise evaluation of leptonic decay rates\nwith emission of a hard photon are also very interesting, especially for the\ndecays of heavy $D$ and $B$ mesons for which currently only model-dependent\npredictions are available to compare with existing experimental data.",
        "positive": "Spectral properties of quarks above Tc -- thermal mass, dispersion\n  relation, and self-energy --: Spectral properties of quarks above the critical temperature for\ndeconfinement are analyzed in quenched lattice QCD on lattices of size\n128^3x16. We study quark spectral function in energy and momentum space,\nfocusing on the values of the thermal mass and the dispersion relations of\nnormal and plasmino modes at nonzero momentum, as well as their spatial volume\ndependence. Our numerical result suggests that the dispersion relation of the\nplasmino mode has a minimum at nonzero momentum even near the critical\ntemperature. The quark self-energy is also analyzed by using the analyticy of\nthe inverse propagator, which is found to be consistent with the spectral\nfunction estimated by the two-pole ansatz."
    },
    {
        "anchor": "Subleading properties of the QCD flux-tube in 3-d lattice gauge theory: We study the continuum limit of the string-like behaviour of flux tubes\nformed between static quarks and anti-quarks in three dimensional SU(2) lattice\ngauge theory. We compare our simulation data with the predictions of both\neffective string models as well as perturbation theory. On the string side we\nobtain clear evidence for convergence of data to predictions of Nambu-Goto\ntheory. We comment on the scales at which the static potential starts departing\nfrom one loop perturbation theory and then again being well described by\neffective string theories. We also estimate the leading corrections to the\none-loop perturbative potential as well as the Nambu-Goto effective string. In\nthe intermediate regions we find an empirical formula which gives surprisingly\ngood fits.",
        "positive": "B meson spectrum and decay constant from Nf=2 simulations: We report on the status of an ALPHA Collaboration project to extract\nquantities for B physics phenomenology from Nf=2 lattice simulations. The\nframework is Heavy Quark Effective Theory (HQET) expanded up to the first order\nof the inverse b-quark mass. The couplings of the effective theory are\ndetermined by imposing matching conditions of observables computed in HQET with\ntheir counterpart computed in QCD. That program, based on Nf=2 simulations in a\nsmall physical volume with SF boundary conditions, is now almost finished. On\nthe other side the analysis of configurations selected from the CLS ensembles,\nin order to measure HQET hadronic matrix elements, has just started recently so\nthat only results obtained at a single lattice spacing, a=0.07 fm, will be\ndiscussed. We give our first results for the b-quark mass and for the B meson\ndecay constant."
    },
    {
        "anchor": "Scattering of two and three physical pions at maximal isospin from\n  lattice QCD: We present the first direct $N_f=2$ lattice QCD computation of two- and\nthree-$\\pi^+$ scattering quantities that includes an ensemble at the physical\npoint. We study the quark mass dependence of the two-pion phase shift, and the\nthree-particle interaction parameters. We also compare to phenomenology and\nchiral perturbation theory (ChPT). In the two-particle sector, we observe good\nagreement to the phenomenological fits in $s$- and $d$-wave, and obtain $M_\\pi\na_0 = -0.0481(86)$ at the physical point from a direct computation. In the\nthree-particle sector, we observe reasonable agreement at threshold to the\nleading order chiral expansion, i.e.\\@ a mildly attractive three-particle\ncontact term. In contrast, we observe that the energy-dependent part of the\nthree-particle quasilocal scattering quantity is not well described by leading\norder ChPT.",
        "positive": "On the degrees of freedom of lattice electrodynamics: Using Euler's formula for a network of polygons for 2D case (or polyhedra for\n3D case), we show that the number of dynamic\\textit{\\}degrees of freedom of the\nelectric field equals the number of dynamic degrees of freedom of the magnetic\nfield for electrodynamics formulated on a lattice. Instrumental to this\nidentity is the use (at least implicitly) of a dual lattice and of a (spatial)\ngeometric discretization scheme based on discrete differential forms. As a\nby-product, this analysis also unveils a physical interpretation for Euler's\nformula and a geometric interpretation for the Hodge decomposition."
    },
    {
        "anchor": "Z-Vortex Percolation in the Electroweak Crossover Region: We study the statistical properties of Z-vortices and Nambu monopoles in the\n3D SU(2) Higgs model for a Higgs mass M_H \\approx 100 GeV near and above the\ncrossover temperature, where these defects are thermally excited. Although\nthere is no phase transition at that strong selfcoupling, we observe that the\nZ-vortices exhibit the percolation transition that has been found recently to\naccompany the first order thermal transition that exists at smaller Higgs mass.\nAbove the crossover temperature percolating networks of Z-vortex lines are\nubiquitous, whereas vortices form a dilute gas of closed vortex loops and\n(Nambu) monopolium states on the low-temperature side of the crossover. The\npercolation temperature turns out to be roughly independent of the lattice\nspacing. We find that the Higgs modulus is smaller (the gauge action is larger)\ninside the vortices, compared to the bulk average. This correlation becomes\nvery strong on the low-temperature side. The percolation transition is a\nprerequisite of some string mediated baryon number generation scenarios.",
        "positive": "Nonlocal field correlators on the lattice in HP^1 sigma-model: Connected two-point field strength correlators have been measured on the\nlattice in quaternionic projective sigma-model of pure SU(2) Yang-Mills theory.\nThe correlation lengths, extracted from the exponential fit for these\ncorrelators, are found to be lambda_1^{-1} = 1.40(3) GeV and lambda^{-1} =\n1.51(3) GeV in good agreement with other existing calculations. The dependence\nof bilocal functions on the connector shape was studied."
    },
    {
        "anchor": "Challenges of Lattice Calculation of Scalar Mesons: I review a proposed pattern of the light scalar mesons with q\\bar{q} mesons\nand glueball above 1 GeV and tetraquark mesoniums below 1 GeV. Several\nchallenges and caveats of calculating these light scalar mesons with dynamical\nfermions are discussed.",
        "positive": "An exact algorithm for three-flavor QCD with $O(a)$-improved Wilson\n  fermions: We present an exact dynamical QCD simulation algorithm for the\n$O(a)$-improved Wilson fermion with odd number of flavors. Our algorithm is an\nextension of the non-Hermitian polynomials HMC algorithm proposed by Takaishi\nand de Forcrand previously. In our algorithm, the systematic errors caused by\nthe polynomial approximation of the inverse of Dirac operator is removed by a\nnoisy-Metropolis test. For one flavor quark it is achieved by taking the square\nroot of the correction matrix explicitly. We test our algorithm for the case of\n$N_f=1+1$ on a moderately large lattice size ($16^3\\times48$). The $N_f=2+1$\ncase is also investigated."
    },
    {
        "anchor": "Lattice NRQCD study of quarkonium at non-zero temperature: To study the in-medium modification of quarkonium properties, charmonium\ncorrelators at $140.4 (\\beta =6.664) \\le T \\le 221 (\\beta = 7.280)$ (MeV) are\ncalculated using the NRQCD formalism on $48^3 \\times 12$ gauge configurations\nwith dynamical $N_f = 2 + 1$ flavors of Highly Improved Staggered Quarks\n(HISQ). To determine the \"zero energy shift\" for these lattices, we perform a\nfine zero temperature scan ($\\beta =6.664, 6.740, 6.800, 6.880, 6.950, 7.030,\n7.150$ and $7.280$). We find that the temperature dependence of charmonium\ncorrelators is stronger than the temperature dependence of bottomonium\ncorrelators in a given channel. This fits into the expected pattern of\nsequential quarkonium melting.",
        "positive": "Lattice QCD as a video game: The speed, bandwidth and cost characteristics of today's PC graphics cards\nmake them an attractive target as general purpose computational platforms. High\nperformance can be achieved also for lattice simulations but the actual\nimplementation can be cumbersome. This paper outlines the architecture and\nprogramming model of modern graphics cards for the lattice practitioner with\nthe goal of exploiting these chips for Monte Carlo simulations. Sample code is\nalso given."
    },
    {
        "anchor": "Dynamical solution of the strong CP problem within QCD ?: The strong CP problem is inseparably connected with the topology of gauge\nfields and the mechanism of color confinement, which requires nonperturbative\ntools to solve it. In this talk I present results of a recent lattice\ninvestigation of QCD with the $\\theta$ term in collaboration with Yoshifumi\nNakamura. The tool we are using to address the nonperturbative properties of\nthe theory is the gradient flow, which is a particular realization of momentum\nspace RG transformations. The novel result is that within QCD the vacuum angle\n$\\theta$ is renormalized, together with the strong coupling constant, and flows\nto $\\theta = 0$ in the infrared limit. This means that CP is conserved by the\nstrong interactions.",
        "positive": "Overlap Quark Propagator in Coulomb Gauge QCD: The chirally symmetric Overlap quark propagator is explored in Coulomb gauge.\nThis gauge is well suited for studying the relation between confinement and\nchiral symmetry breaking, since confinement can be attributed to the infrared\ndivergent Lorentz-vector dressing function. Using quenched gauge field\nconfigurations on a $20^4$ lattice, the quark propagator dressing functions are\nevaluated, the dynamical quark mass is extracted and the chiral limit of these\nquantities is discussed. By removing the low-lying modes of the Dirac operator,\nchiral symmetry is artificially restored. Its effect on the dressing functions\nis discussed."
    },
    {
        "anchor": "Thermodynamical Observables in a Finite Temperature Window from the\n  Monte Carlo Hamiltonian: The Monte Carlo (MC) Hamiltonian is a new stochastic method to solve\nmany-body problems. The MC Hamiltonian represents an effective Hamiltonian in a\nfinite energy window. We construct it from the classical action via Monte Carlo\nwith importance sampling. The MC Hamiltonian yields the energy spectrum and\ncorresponding wave functions in a low energy window. This allows to compute\nthermodynamical observables in a low temperature window. We show the working of\nthe MC Hamiltonian by an example from lattice field theory (Klein-Gordon\nmodel).",
        "positive": "Finite-volume meson propagators in quenched chiral perturbation theory: We compute meson propagators in finite-volume quenched chiral perturbation\ntheory."
    },
    {
        "anchor": "Study of the running coupling constant in 10-flavor QCD with the\n  Schr\u00f6dinger functional method: The electroweak gauge symmetry is allowed to be spontaneously broken by the\nstrongly interacting vector-like gauge dynamics. When the gauge coupling of a\ntheory runs slowly in a wide range of energy scale, the theory is a candidate\nfor walking technicolor. This may open up the possibility that the origin of\nall masses may be traced back to the gauge theory. We use the \\SF method to see\nwhether the gauge coupling of 10-flavor QCD \"walks\" or not. Preliminary result\nis reported.",
        "positive": "Remarks on Lattice Gauge Fixing: In this talk I briefly comment on the conventional lattice gauge fixing\nadopting a critical, even though constructive, numerical point of view."
    },
    {
        "anchor": "Reducing Residual-Mass Effects for Domain-Wall Fermions: It has been suggested to project out a number of low-lying eigenvalues of the\nfour-dimensional Wilson--Dirac operator that generates the transfer matrix of\ndomain-wall fermions in order to improve simulations with domain-wall fermions.\nWe investigate how this projection method reduces the residual chiral\nsymmetry-breaking effects for a finite extent of the extra dimension. We use\nthe standard Wilson as well as the renormalization--group--improved gauge\naction. In both cases we find a substantially reduced residual mass when the\nprojection method is employed. In addition, the large fluctuations in this\nquantity disappear.",
        "positive": "Maximum-Likelihood Approach to Topological Charge Fluctuations in\n  Lattice Gauge Theory: We present a novel technique for the determination of the topological\nsusceptibility (related to the variance of the distribution of global\ntopological charge) from lattice gauge theory simulations, based on\nmaximum-likelihood analysis of the Markov-chain Monte Carlo time series. This\ntechnique is expected to be particularly useful in situations where relatively\nfew tunneling events are observed. Restriction to a lattice subvolume on which\ntopological charge is not quantized is explored, and may lead to further\nimprovement when the global topology is poorly sampled. We test our proposed\nmethod on a set of lattice data, and compare it to traditional methods."
    },
    {
        "anchor": "Improvement of N_f=3 lattice QCD with Wilson fermions and tree-level\n  improved gauge action: We determine the parameter c_SW required for O(a)-improvement of the three\nflavor Wilson fermion action together with the tree-level Symanzik improved\ngauge action. The standard improvement condition is employed for a range of\ncouplings. Additionally, we perform a check of the volume independence of c_SW\nand provide a preliminary estimate of the lattice spacing at our largest values\nof g_0^2.",
        "positive": "Three-Quark Potential in SU(3) Lattice QCD: The static three-quark (3Q) potential is measured in the SU(3) lattice QCD\nwith $12^3 \\times 24$ and $\\beta=5.7$ at the quenched level. From the 3Q Wilson\nloop, the 3Q ground-state potential $V_{\\rm 3Q}$ is extracted using the\nsmearing technique for the ground-state enhancement. With accuracy better than\na few %, $V_{\\rm 3Q}$ is well described by a sum of a constant, the two-body\nCoulomb term and the three-body linear confinement term $\\sigma_{\\rm 3Q} L_{\\rm\nmin}$, where $L_{\\rm min}$ denotes the minimal length of the color flux tube\nlinking the three quarks. By comparing with the Q-$\\bar {\\rm Q}$ potential, we\nfind a universal feature of the string tension, $\\sigma_{\\rm 3Q} \\simeq\n\\sigma_{\\rm Q \\bar Q}$, as well as the one-gluon-exchange result for the\nCoulomb coefficient, $A_{\\rm 3Q} \\simeq \\frac12 A_{\\rm Q \\bar Q}$."
    },
    {
        "anchor": "Non-leptonic kaon decays at large $N_c$: We study the scaling with the number of colors $N_c$ of the weak amplitudes\nmediating kaon mixing and decay, in the limit of light charm masses\n($m_u=m_d=m_s=m_c$). The amplitudes are extracted directly on the lattice for\n$N_c = 3-7$ (with preliminar results for $N_c = 8$ and $17$) using twisted mass\nQCD. It is shown that the (sub-leading) $1/N_c$ corrections to $\\hat B_K$ are\nsmall and that the naive $N_c \\to \\infty$ limit, $\\hat B_K = 3/4$, seems to be\nrecovered. On the other hand, the ${\\cal O}\\, (1/N_c)$ corrections in $K \\to\n\\pi \\pi$ amplitudes (derived from $K \\to \\pi$ matrix elements) are large and\nfully anti-correlated in the $I=0$ and $I=2$ channels. This may have some\nimplications for the understanding of the $\\Delta I=1/2$ rule.",
        "positive": "Infrared behavior of gluon and ghost propagators from asymmetric\n  lattices: We present a numerical study of the lattice Landau gluon and ghost\npropagators in three-dimensional pure SU(2) gauge theory. Data have been\nobtained using asymmetric lattices (V = 20^2 X 40, 20^2 X 60, 8^2 X 64, 8^2 X\n140, 12^2 X 140 and 16^2 X 140) for the lattice coupling beta = 3.4, in the\nscaling region. We find that the gluon (respectively ghost) propagator is\nsuppressed (respec. enhanced) at small momenta in the limit of large lattice\nvolume V. By comparing these results with data obtained using symmetric\nlattices (V = 60^3 and 140^3), we find that both propagators suffer from\nsystematic effects in the infrared region (p \\lesssim 650 MeV). In particular,\nthe gluon (respec. ghost) propagator is less IR-suppressed (respec. enhanced)\nthan in the symmetric case. We discuss possible implications of the use of\nasymmetric lattices."
    },
    {
        "anchor": "Non-Perturbative Renormalization of Lattice Four-Fermion Operators\n  without Power Subtractions: A general non-perturbative analysis of the renormalization properties of\n$\\Delta I=3/2$ four-fermion operators in the framework of lattice\nregularization with Wilson fermions is presented. We discuss the\nnon-perturbative determination of the operator renormalization constants in the\nlattice Regularization Independent (RI or MOM) scheme. We also discuss the\ndetermination of the finite lattice subtraction coefficients from Ward\nIdentities. We prove that, at large external virtualities, the determination of\nthe lattice mixing coefficients, obtained using the RI renormalization scheme,\nis equivalent to that based on Ward Identities, in the continuum and chiral\nlimits. As a feasibility study of our method, we compute the mixing matrix at\nseveral renormalization scales, for three values of the lattice coupling\n$\\beta$, using the Wilson and tree-level improved SW-Clover actions.",
        "positive": "Critical exponents of a three dimensional O(4) spin model: By Monte Carlo simulation we study the critical exponents governing the\ntransition of the three-dimensional classical O(4) Heisenberg model, which is\nconsidered to be in the same universality class as the finite-temperature QCD\nwith massless two flavors. We use the single cluster algorithm and the\nhistogram reweighting technique to obtain observables at the critical\ntemperature. After estimating an accurate value of the inverse critical\ntemperature $\\Kc=0.9360(1)$, we make non-perturbative estimates for various\ncritical exponents by finite-size scaling analysis. They are in excellent\nagreement with those obtained with the $4-\\epsilon$ expansion method with\nerrors reduced to about halves of them."
    },
    {
        "anchor": "New algorithms and new results for strong coupling LQCD: We present and compare new types of algorithms for lattice QCD with staggered\nfermions in the limit of infinite gauge coupling. These algorithms are\nformulated on a discrete spatial lattice but with continuous Euclidean time.\nThey make use of the exact Hamiltonian, with the inverse temperature beta as\nthe only input parameter. This formulation turns out to be analogous to that of\na quantum spin system. The sign problem is completely absent, at zero and\nnon-zero baryon density. We compare the performance of a continuous-time worm\nalgorithm and of a Stochastic Series Expansion algorithm (SSE), which operates\non equivalence classes of time-ordered interactions. Finally, we apply the SSE\nalgorithm to a first exploratory study of two-flavor strong coupling lattice\nQCD, which is manageable in the Hamiltonian formulation because the sign\nproblem can be controlled.",
        "positive": "On the generalized eigenvalue method for energies and matrix elements in\n  lattice field theory: We discuss the generalized eigenvalue problem for computing energies and\nmatrix elements in lattice gauge theory, including effective theories such as\nHQET. It is analyzed how the extracted effective energies and matrix elements\nconverge when the time separations are made large. This suggests a particularly\nefficient application of the method for which we can prove that corrections\nvanish asymptotically as $\\exp(-(E_{N+1}-E_n) t)$. The gap $E_{N+1}-E_n$ can be\nmade large by increasing the number $N$ of interpolating fields in the\ncorrelation matrix. We also show how excited state matrix elements can be\nextracted such that contaminations from all other states disappear\nexponentially in time. As a demonstration we present numerical results for the\nextraction of ground state and excited B-meson masses and decay constants in\nstatic approximation and to order $1/m_b$ in HQET."
    },
    {
        "anchor": "A QCD chiral critical point at small chemical potential: is it there or\n  not?: For a QCD chiral critical point to exist, the parameter region of small quark\nmasses for which the finite temperature transition is first-order must expand\nwhen the chemical potential is turned on. This can be tested by a Taylor\nexpansion of the critical surface (m_{u,d},m_s)_c(mu). We present a new method\nto perform this Taylor expansion numerically, which we first test on an\neffective model of QCD with static, dense quarks. We then present the results\nfor QCD with 3 degenerate flavors. For a lattice with N_t=4 time-slices, the\nfirst-order region shrinks as the chemical potential is turned on. This implies\nthat, for physical quark masses, the analytic crossover which occurs at mu=0\nbetween the hadronic and the plasma regimes remains crossover in the mu-region\nwhere a Taylor expansion is reliable, i.e. mu less than or similar to T. We\npresent preliminary results from finer lattices indicating that this situation\npersists, as does the discrepancy between the curvature of T_c(m_c(mu=0),mu)\nand the experimentally observed freeze-out curve.",
        "positive": "Sphaleron rate at high temperature in 1+1 dimensions: We resolve the controversy in the high temperature behavior of the sphaleron\nrate in the abelian Higgs model in 1+1 dimensions. The $T^2$ behavior at\nintermediate lattice spacings is found to change into $T^{2/3}$ behavior in the\ncontinuum limit. The results are supported by analytic arguments that the\nclassical approximation is good for this model."
    },
    {
        "anchor": "Polyakov loop in 2+1 flavor QCD from low to high temperatures: We study the free energy of a static quark in QCD with 2+1 flavors in a wide\ntemperature region, 116 MeV $< T < $ 5814 MeV, using the highly improved\nstaggered quark (HISQ) action. We analyze the transition region in detail,\nobtain the entropy of a static quark, show that it peaks at temperatures close\nto the chiral crossover temperature and also revisit the temperature dependence\nof the Polyakov loop susceptibilities using gradient flow. We discuss the\nimplications of our findings for the deconfinement and chiral crossover\nphenomena at physical values of the quark masses. Finally a comparison of the\nlattice results at high temperatures with the weak-coupling calculations is\npresented.",
        "positive": "Deconfinement phase transitions in external fields: We compare vacuum dynamics of abelian versus non abelian lattice gauge\ntheories in presence of external fields. We find that the deconfinement\ntemperature of non abelian theories depends on the strength of a constant\nabelian chromomagnetic field end eventually goes to zero. On the contrary such\nan effect is not shared by abelian theories. We argue on the relevance of this\nresult to understand the QCD vacuum."
    },
    {
        "anchor": "RG inspired Machine Learning for lattice field theory: Machine learning has been a fast growing field of research in several areas\ndealing with large datasets. We report recent attempts to use Renormalization\nGroup (RG) ideas in the context of machine learning. We examine coarse graining\nprocedures for perceptron models designed to identify the digits of the MNIST\ndata. We discuss the correspondence between principal components analysis (PCA)\nand RG flows across the transition for worm configurations of the 2D Ising\nmodel. Preliminary results regarding the logarithmic divergence of the leading\nPCA eigenvalue were presented at the conference and have been improved after.\nMore generally, we discuss the relationship between PCA and observables in\nMonte Carlo simulations and the possibility of reduction of the number of\nlearning parameters in supervised learning based on RG inspired hierarchical\nansatzes.",
        "positive": "Chiral gauged fermions on a lattice: The chiral fermion model with local multifermion interactions proposed in\nNucl. Phys. B486 (1997) 282 and Phys. Rev. D61 (2000) 054502 processes an exact\nSU_L(2) chiral gauge symmetry and SU_L(2) by U_R(1) chiral flavour symmetry on\na lattice and a plausible scaling region for the target chiral gauge theory in\nthe continuum limit. Following the previous analysis of massive and massless\nfermion spectra in the scaling region, we compute the coupling vertices between\ngauge field and fermions by the strong multifermion coupling expansion and\nanalytical continuation of these vertex functions in the energy-momentum space.\nWe show a peculiar scenario that a massless fermion is SU_L(2)-chirally gauged\nin the low energy and 15 non-degenerate massive Dirac fermions are\nSU_L(2)-vectorially gauged at the lattice scale O(1/a). The Ward identities\nassociated to the chiral gauge symmetry are realized by both the massless\nchiral fermion and massive Dirac fermions. These Ward identities protect the\nperturbative calculations in the small gauge coupling from hard gauge-symmetry\nbreakings and lead to the normal gauge-invariant renormalization prescription.\nThe vacuum functional is perturbatively computed by a continuum regularization\nscheme in 16 edges of Brillouin zones. We achieve the correct form of the gauge\nanomaly and U_L(1) fermion-flavour singlet anomaly with the soft chiral\nsymmetry breaking scale that is much smaller than the lattice scale. The\nresidual breakings of chiral gauge symmetry after the gauge anomaly\ncancellation are eliminated in the normal gauge-invarinant renormalization\nprescription. We discuss the consistency of the scenario and the reasons for it\nto work for perturbative and non-perturbative gauge field."
    },
    {
        "anchor": "Comment on \"'t Hooft vertices, partial quenching, and rooted staggered\n  QCD\": A recent criticism of the proof of the failure of the rooting procedure with\nstaggered fermions is shown to be incorrect.",
        "positive": "Topological charge in 1+1 dimensional lattice $\u03c6^4$ theory: We investigate the topological charge in 1+1 dimensional $\\phi^4$ theory on a\nlattice with Anti Periodic Boundary Condition (APBC) in the spatial direction.\nWe propose a simple order parameter for the lattice theory with APBC and we\ndemonstrate its effectiveness. Our study suggests that kink condensation is a\npossible mechanism for the order-disorder phase transition in the 1+1\ndimensional $\\phi^4$ theory. With renormalizations performed on the lattice\nwith Periodic Boundary Condition (PBC), the topological charge in the\nrenormalized theory is given as the ratio of the order parameters in the\nlattices with APBC and PBC. We present a comparison of topological charges in\nthe bare and the renormalized theory and demonstrate invariance of the charge\nof the renormalized theory in the broken symmetry phase."
    },
    {
        "anchor": "Deconfinement in QCD with dynamical quarks: We study the phase structure of full QCD within the canonical ensemble with\nrespect to triality in a lattice formulation. The procedure for the calculation\nof the effective potentials in this case is given. As an example we consider\nthe three dimensional SU(2) gauge model at finite temperatures in the strong\ncoupling region. The potential exhibits a deconfinement phase transition unlike\nthe similar potential obtained in the grand canonical ensemble which\ndemonstrates explicit Z(N) symmetry breaking at any temperature. Furthermore,\nwe investigate the effective potential with the chiral condensate included. In\ncontradiction to other authors, we find chiral symmetry restoration in all\ntriality sectors. In the scheme with massless staggered fermions we observe\nchiral symmetry restoration accompanying a deconfinement phase transition of\nfirst order. Above the critical point, besides two Z(2) symmetric \"deconfining\"\nvacua there exists a metastable \"confining\" vacuum in a wide region of\nparameters. Such a picture could be interpreted as an indication on a mixed\nstate of hadrons and quarks in the vicinity of the critical line.",
        "positive": "Transition temperature and the equation of state from lattice QCD,\n  Wuppertal-Budapest results: The QCD transition is studied on lattices up to $N_t=16$. The chiral\ncondensate is presented as a function of the temperature, and the corresponding\ntransition temperature is extracted. The equation of state is determined on\nlattices with $N_t=6,8,10$ and at some temperature values with $N_t=12$. The\npressure and the trace anomaly are presented as functions of the temperature in\nthe range 100 ...1000 MeV . Using the same configurations we determine the\ncontinuum extrapolated phase diagram of QCD on the $\\mu-T$ plane for small to\nmoderate chemical potentials. Two transition lines are defined with two\nquantities, the chiral condensate and the strange quark number susceptibility."
    },
    {
        "anchor": "The scalar does not decay at finite temperatures: We investigate medium effects on mesonic screening lengths for QCD with\n2-flavours of dynamical staggered quarks on lattices with cutoff a=1/6T.\nDenoting the cross-over temperature by $T_c$, we vary the temperature T from\n0.89$T_c$ to 1.92$T_c$, spanning both the hadronic and quark gluon plasma\nphases. While chiral symmetry restoration in the vector channel appears to take\nplace near $T_c$, it is seen in the scalar channel only above 1.33 $T_c$.\nVarying spatial lattice sizes, we find very little volume dependence in our\nresults at 0.94 $T_c$. We discuss the stability of the scalar meson at these\ntemperatures.",
        "positive": "Lattice QCD simulations with light dynamical quarks: I report recent results from full QCD simulations by CP-PACS and JLQCD\ncollaborations."
    },
    {
        "anchor": "Phase diagrams of a Higgs-Yukawa system with chirally invariant lattice\n  fermion actions: We study the phase structure of a $Z_2$ lattice Higgs-Yukawa system with\ndifferent forms of chirally invariant lattice fermion actions: naive, two types\nof non-local actions, and a mirror fermion action. The calculations are\nperformed in the variational mean field approximation with contribution of\nfermionic determinant being calculated in a ladder approximation. We\ndemonstrate that the phase structure of the system crucially depends on the\nform of the lattice fermion action, despite the fact that the Higgs field\ncouples to fermions in the same local way. A possibility of defining chiral\ngauge theories based on mirror fermion action is briefly discussed.",
        "positive": "Domain decomposition, multi-level integration and exponential noise\n  reduction in lattice QCD: We explore the possibility of computing fermionic correlators on the lattice\nby combining a domain decomposition with a multi-level integration scheme. The\nquark propagator is expanded in series of terms with a well defined\nhierarchical structure. The higher the order of a term, the (exponentially)\nsmaller its magnitude, the less local is its dependence on the gauge field.\nOnce inserted in a Wick contraction, the gauge-field dependence of the terms in\nthe resulting series can be factorized so that it is suitable for multi-level\nMonte Carlo integration. We test the strategy in quenched QCD by computing the\ndisconnected correlator of two flavor-diagonal pseudoscalar densities, and a\nnucleon two-point function. In either cases we observe a significant\nexponential increase of the signal-to-noise ratio."
    },
    {
        "anchor": "Universal behaviour of the SU(2) running coupling constant in the\n  continuum limit: We present data from the ALPHA Collaboration about lattice calculation of\nSU(2) pure--gauge running coupling constant, obtained with two different\ndefinitions of the coupling itself, which show universality of the continuum\nlimit and clarify the applicability of renormalized perturbation theory.",
        "positive": "Locality and Scaling of Quenched Overlap Fermions: The overlap fermion offers the tremendous advantage of exact chiral symmetry\non the lattice, but is numerically intensive. This can be made affordable while\nstill providing large lattice volumes, by using coarse lattice spacing, given\nthat good scaling and localization properties are established. Here, using\noverlap fermions on quenched Iwasaki gauge configurations, we demonstrate\ndirectly that the overlap Dirac operator's range is comfortably small in\nlattice units for each of the lattice spacings 0.20 fm, 0.17 fm, and 0.13 fm\n(and scales to zero in physical units in the continuum limit). In particular,\nour direct results contradict recent speculation that an inverse lattice\nspacing of $1 {\\rm GeV}$ is too low to have satisfactory localization.\nFurthermore, hadronic masses (available on the two coarser lattices) scale very\nwell."
    },
    {
        "anchor": "Simple QED- and QCD-like Models at Finite Density: In this paper we discuss one-dimensional models reproducing some features of\nquantum electrodynamics and quantum chromodynamics at nonzero density and\ntemperature. Since a severe sign problem makes a numerical treatment of QED and\nQCD at high density difficult, such models help to explore various effects\npeculiar to the full theory. Studying them gives insights into the large\ndensity behavior of the Polyakov loop by taking both bosonic and fermionic\ndegrees of freedom into account, although in one dimension only the\nimplementation of a global gauge symmetry is possible. For these models we\nevaluate the respective partition functions and discuss several observables as\nwell as the Silver Blaze phenomenon.",
        "positive": "The Behavior of Vortex Loops in the 3-d XY Model: The behavior of vortex loops is studied in the 3-d XY model. It is found that\nthe phase transtiton of the 3-d XY model is caused by percolating vortex loops."
    },
    {
        "anchor": "Two-particle scattering from finite-volume quantization conditions using\n  the plane wave basis: We propose an alternative approach to L\\\"uscher's formula for extracting\ntwo-body scattering phase shifts from finite volume spectra with no reliance on\nthe partial wave expansion. We use an effective-field-theory-based Hamiltonian\nmethod in the plane wave basis and decompose the corresponding matrix elements\nof operators into irreducible representations of the relevant point groups. The\nproposed approach allows one to benefit from the knowledge of the long-range\ninteraction and avoids complications from partial wave mixing in a finite\nvolume. We consider spin-singlet channels in the two-nucleon system and\npion-pion scattering in the $\\rho$-meson channel in the rest and moving frames\nto illustrate the method for non-relativistic and relativistic systems,\nrespectively. For the two-nucleon system, the long-range interaction due to the\none-pion exchange is found to make the single-channel L\\\"uscher formula\nunreliable at the physical pion mass. For S-wave dominated states, the\nsingle-channel L\\\"uscher method suffers from significant finite-volume\nartifacts for a $L=3$~fm box, but it works well for boxes with $L>5$~fm.\nHowever, for P-wave dominated states, significant partial wave mixing effects\nprevent the application of the single-channel L\\\"uscher formula regardless of\nthe box size (except for the near-threshold region). Using a toy model to\ngenerate synthetic data for finite-volume energies, we show that our\neffective-field-theory-based approach in the plane wave basis is capable of a\nreliable extraction of the phase shifts. For pion-pion scattering, we employ a\nphenomenological model to fit lattice QCD results at the physical pion mass.\nThe extracted P-wave phase shifts are found to be in a good agreement with the\nexperimental results.",
        "positive": "Heavy flavour phenomenology from lattice QCD: The focus of this report is the lattice calculation of hadronic parameters\nrelevant to heavy flavour phenomenology. I will review recent results and the\ncurrent status of studies of the B and D decay constants, semileptonic decay\nform factors, B^0-\\bar B^0 mixing, and determinations of the quark masses m_c\nand m_b. Some studies of heavy flavour observables have used current lattice\nresults to derive Standard Model predictions that seem to disagree with\nexperimental measurements. That is the case, for example, of sin(2\\beta) and\nf_{D_s}. This report discusses efforts to resolvethe origin of those\ndiscrepancies from the lattice side."
    },
    {
        "anchor": "Light composite scalar in twelve-flavor QCD on the lattice: Based on lattice simulations using highly improved staggered quarks for\ntwelve-flavor QCD with several bare fermion masses, we observe a flavor-singlet\nscalar state lighter than the pion in the correlators of fermionic\ninterpolating operators. The same state is also investigated using correlators\nof gluonic interpolating operators. Combined with our previous study, that\nshowed twelve-flavor QCD to be consistent with being in the conformal window,\nwe infer that the lightness of the scalar state is due to infrared\nconformality. This result shed some light on the possibility of a light\ncomposite Higgs boson (\"technidilaton\") in walking technicolor theories.",
        "positive": "I=2 Two-Pion Wave Functions with Non-zero Total Momentum: We calculate the two-pion wave function for the I=2 $S$-wave two-pion system\nwith a finite scattering momentum and estimate the interaction range between\ntwo pions. It allows us to examine the validity of the necessary condition for\nthe finite-volume method for the scattering phase shift. A calculation is\ncarried out with a plaquette gauge action for gluons and a clover-improved\nWilson action for quarks at $1/a=1.63 {\\rm GeV}$ on $32^3\\times 120$ lattice in\nthe quenched approximation. We conclude that the necessary condition is\nsatisfied within statistical errors for the lattice size $L\\ge 32$, when the\nquark mass is in the range $m_\\pi^2=0.176 - 0.345 {\\rm GeV}^2$ and the\nscattering momentum in $k^2 < 0.026 {\\rm GeV}^2$. We also find that the energy\ndependence of the interaction range is small and it takes $1.2-1.7 {\\rm fm}$\nfor our simulation parameters. We obtain the phase shift from the two-pion wave\nfunction with a smaller statistical error than that from the conventional\nanalysis with the two-pion time correlator."
    },
    {
        "anchor": "Fast Fits for Lattice QCD Correlators: We illustrate a technique for fitting lattice QCD correlators to sums of\nexponentials that is significantly faster than traditional fitting methods ---\n10--40 times faster for the realistic examples we present. Our examples are\ndrawn from a recent analysis of the Upsilon spectrum, and another recent\nanalysis of the D -> pi semileptonic form factor. For single correlators, we\nshow how to simplify traditional effective-mass analyses.",
        "positive": "Scalar Quarkonium Masses and Mixing with the Lightest Scalar Glueball: We evaluate the continuum limit of the valence (quenched) approximation to\nthe mass of the lightest scalar quarkonium state for a range of different quark\nmasses and to the mixing energy between these states and the lightest scalar\nglueball. Our results support the interpretation of $f_0(1710)$ as composed\nmainly of the lightest scalar glueball."
    },
    {
        "anchor": "Chiral 1/M^2 corrections to B^(*) -> D^(*) at Zero Recoil in Quenched\n  Chiral Perturbation Theory: Heavy quark effective theory can be used to calculate the values of the\nsemileptonic B^(*) -> D^(*) decays in the limit that the heavy quark masses are\ninfinite. We calculate the lowest order chiral corrections, which are of\nO(1/M^2), from the breaking of heavy quark symmetry at the zero recoil point in\nquenched chiral perturbation theory. These results will aid in the\nextrapolation of quenched lattice calculations from the light quark masses used\non the lattice down to the physical ones.",
        "positive": "Lattice QCD gluon propagators near transition temperature: Landau gauge gluon propagators are studied numerically in the SU(3)\ngluodynamics as well as in the full QCD with the number of flavors $n_F=2$\nusing efficient gauge fixing technique. We compare these propagators at\ntemperatures very close to the transition point in two phases : confinement and\ndeconfinement. The electric mass $m_E$ has been determined from the momentum\nspace longitudinal gluon propagator. Gribov copy effects are found to be rather\nstrong in the gluodynamics, while in the full QCD case they are weak (\"Gribov\nnoise\"). Also we analyse finite volume dependence of the transverse and\nlongitudinal propagators."
    },
    {
        "anchor": "One-loop matching of $CP$-odd four-quark operators to the gradient-flow\n  scheme: The translation of experimental limits on the neutron electric dipole moment\ninto constraints on heavy $CP$-violating physics beyond the Standard Model\nrequires knowledge about non-perturbative matrix elements of effective\noperators, which ideally should be computed in lattice QCD. However, this\nnecessitates a matching calculation as an interface to the effective field\ntheory framework, which is based on dimensional regularization and\nrenormalization by minimal subtraction. We calculate the one-loop matching\nbetween the gradient-flow and minimal-subtraction schemes for the\n$CP$-violating four-quark operators contributing to the neutron electric dipole\nmoment. The gradient flow is a modern regularization-independent scheme\namenable to lattice computations that promises, e.g., better control over power\ndivergences than traditional momentum-subtraction schemes. Our results extend\nprevious work on dimension-five operators and provide a necessary ingredient\nfor future lattice-QCD computations of the contribution of four-quark operators\nto the neutron electric dipole moment.",
        "positive": "In-medium static inter-quark potential on high resolution quenched\n  lattices: We re-investigate the interactions between static color sources in a finite\ntemperature gluonic medium using both high resolution isotropic and anisotropic\nquenched lattice QCD ensembles. The underlying ill-posed inverse problem,\nrelated to the extraction of spectral functions, is attacked with a range of\ndifferent methods, including Bayesian inference, Pad\\'e interpolation and model\nfits. Among the latter we include a tail amended Gaussian ansatz and a\nHTL-inspired fit ansatz. We reconfirm the presence of a dominant low-lying\nspectral feature that supports the existence of a potential picture for the\nin-medium evolution of the static charges at late real times. Using the raw\nunmodified lattice data, all applicable methods show clear signs of screening\nof the real-part of the potential. After applying a subtraction procedure\nfeatured in a previous study we find however that screening disappears from the\nextracted potential. Paths towards the resolution of this puzzle are discussed."
    },
    {
        "anchor": "Abelian and non-Abelian Berry curvatures in lattice QCD: We studied the Berry curvature of the massive Dirac fermion in 3+1\ndimensions. For the non-interacting Dirac fermion, the Berry curvature is\nnon-Abelian because of the degeneracy of positive and negative helicity modes.\nWe calculated the non-Abelian Berry curvature analytically and numerically. For\nthe interacting Dirac fermion in QCD, the degeneracy is lost because gluons\ncarry helicity and color charge. We calculated the Abelian Berry curvature in\nlattice QCD.",
        "positive": "The $b_1$ resonance in coupled $\u03c0\u03c9$, $\u03c0\u03c6$ scattering from\n  lattice QCD: We present the first lattice QCD calculation of coupled $\\pi\\omega$ and\n$\\pi\\phi$ scattering, incorporating coupled $S$ and $D$-wave $\\pi\\omega$ in\n$J^P=1^+$. Finite-volume spectra in three volumes are determined via a\nvariational analysis of matrices of two-point correlation functions, computed\nusing large bases of operators resembling single-meson, two-meson and\nthree-meson structures, with the light-quark mass corresponding to a pion mass\nof $m_\\pi \\approx 391$ MeV. Utilizing the relationship between the discrete\nspectrum of finite-volume energies and infinite-volume scattering amplitudes,\nwe find a narrow axial-vector resonance ($J^{PC}=1^{+-}$), the analogue of the\n$b_1$ meson, with mass $m_{R}\\approx1380$ MeV and width $\\Gamma_{R}\\approx 91$\nMeV. The resonance is found to couple dominantly to $S$-wave $\\pi\\omega$, with\na much-suppressed coupling to $D$-wave $\\pi\\omega$, and a negligible coupling\nto $\\pi\\phi$ consistent with the `OZI rule'. No resonant behavior is observed\nin $\\pi\\phi$, indicating the absence of a putative low-mass $Z_s$ analogue of\nthe $Z_c$ claimed in $\\pi J/\\psi$. In order to minimally present the contents\nof a unitary three-channel scattering matrix, we introduce an $n$-channel\ngeneralization of the traditional two-channel Stapp parameterization."
    },
    {
        "anchor": "Analytical calculation of critical temperatures in some spin systems: A new method for locating analytically critical temperatures is discussed. It\nis exact for selfdual systems. When applied the two coupled layers of Ising\nspins it deviates from our preliminary Monte Carlo estimates by 1.5 standard\ndeviations. It predicts critical temperature of the three dimensional Ising\nmodel in terms of the solution of the two layer Ising system.",
        "positive": "Equation of state in finite-temperature QCD with two flavors of improved\n  Wilson quarks: We present results of a first study of equation of state in\nfinite-temperature QCD with two flavors of Wilson-type quarks. Simulations are\nmade on lattices with temporal size $N_t=4$ and 6, using an RG-improved action\nfor the gluon sector and a meanfield-improved clover action for the quark\nsector. The lines of constant physics corresponding to fixed values of the\nratio $m_{\\rm PS}/m_{\\rm V}$ of the pseudo-scalar to vector meson masses at\nzero temperature are determined, and the beta functions which describe the\nrenormalization-group flow along these lines are calculated. Using these\nresults, the energy density and the pressure are calculated as functions of\ntemperature along the lines of constant physics in the range $m_{\\rm PS}/m_{\\rm\nV} = 0.65$--0.95. The quark mass dependence in the equation of state is found\nto be small for $m_{\\rm PS}/m_{\\rm V} \\simlt 0.8$. Comparison of results for\n$N_t=4$ and $N_t=6$ lattices show significant scaling violation present in the\n$N_t=4$ results. At high temperatures the results for $N_t=6$ are quite close\nto the continuum Stefan-Boltzmann limit, suggesting the possibility of a\nprecise continuum extrapolation of thermodynamic quantities from simulations at\n$N_t\\simgt 6$."
    },
    {
        "anchor": "Simulated Tempering: A New Monte Carlo Scheme: We propose a new global optimization method ({\\em Simulated Tempering}) for\nsimulating effectively a system with a rough free energy landscape (i.e. many\ncoexisting states) at finite non-zero temperature. This method is related to\nsimulated annealing, but here the temperature becomes a dynamic variable, and\nthe system is always kept at equilibrium. We analyze the method on the Random\nField Ising Model, and we find a dramatic improvement over conventional\nMetropolis and cluster methods. We analyze and discuss the conditions under\nwhich the method has optimal performances.",
        "positive": "Tensor renormalization group and the volume independence in 2D U($N$)\n  and SU($N$) gauge theories: The tensor renormalization group method is a promising approach to lattice\nfield theories, which is free from the sign problem unlike standard Monte Carlo\nmethods. One of the remaining issues is the application to gauge theories,\nwhich is so far limited to U(1) and SU(2) gauge groups. In the case of higher\nrank, it becomes highly nontrivial to restrict the number of representations in\nthe character expansion to be used in constructing the fundamental tensor. We\npropose a practical strategy to accomplish this and demonstrate it in 2D U($N$)\nand SU($N$) gauge theories, which are exactly solvable. Using this strategy, we\nobtain the singular-value spectrum of the fundamental tensor, which turns out\nto have a definite profile in the large-$N$ limit. For the U($N$) case, in\nparticular, we show that the large-$N$ behavior of the singular-value spectrum\nchanges qualitatively at the critical coupling of the Gross-Witten-Wadia phase\ntransition. As an interesting consequence, we find a new type of volume\nindependence in the large-$N$ limit of the 2D U($N$) gauge theory with the\n$\\theta$ term in the strong coupling phase, which goes beyond the Eguchi-Kawai\nreduction."
    },
    {
        "anchor": "Progress in understanding colour confinement: New results from lattice are presented,which demonstrate that monopoles\ncondense in the vacuum of confined phase of QCD, which is thus a dual\nsuperconductor. Monopoles defined by different abelian projections appear to be\nphysically equivalent.",
        "positive": "Gauge fixing and gauge correlations in noncompact Abelian gauge models: We investigate some general properties of linear gauge fixings and\ngauge-field correlators in lattice models with noncompact U(1) gauge symmetry.\nIn particular, we show that, even in the presence of a gauge fixing, some\ngauge-field observables (like the photon-mass operator) are not well-defined,\ndepending on the specific gauge fixing adopted and on its implementation.\nNumerical tests carried out in the three-dimensional noncompact lattice Abelian\nHiggs model fully support the analytical results and provide further insights."
    },
    {
        "anchor": "Effective theory for quenched lattice QCD and the Aoki phase: We discuss the symmetries of quenched QCD with Wilson fermions, starting from\nits lagrangian formulation, taking into account the constraints needed for\nconvergence of the ghost-quark functional integral. We construct the\ncorresponding chiral effective lagrangian, including terms linear and quadratic\nin the lattice spacing. This allows us to study the phase structure of the\nquenched theory, and compare it to that in the unquenched theory. In particular\nwe study whether there may be an Aoki phase (with parity and flavor\nspontaneously broken) or a first order transition line (with no symmetry\nbreaking but meson masses proportional to the lattice spacing), which are the\ntwo possibilities in the unquenched theory. The presence of such phase\nstructure, and the concomitant long-range correlations, has important\nimplications for numerical studies using both quenched and dynamical overlap\nand domain-wall fermions. We argue that the phase structure is qualitatively\nthe same as in the unquenched theory, with the choice between the two\npossibilities depending on the sign of a parameter in the low-energy effective\ntheory.",
        "positive": "Resonance Parameters for the rho-meson from Lattice QCD: We present a calculation of the phase-shift for $\\pi$-$\\pi$ scattering in\nisospin-1, spin-1 channel in the elastic region. The mass and width of the rho\nresonance is extracted by fitting these phaseshifts. To vary the scattering\nmomentum we employ asymmetric boxes. We use $N_f = 2$ nHYP-smeared clover\nfermions and generate two sets of ensembles with pion masses about 315MeV and\n227MeV. To determine the phase shifts we compute the energy spectrum both for\nstates at rest and boosted. We employ a variational analysis with interpolating\nfields including several $q$-$\\bar{q}$ and $\\pi$-$\\pi$ interpolating fields\nwith different scattering momenta."
    },
    {
        "anchor": "Exploring the QCD phase diagram at finite density by the complex\n  Langevin method on a $16^3\\times 32$ lattice: We explore the QCD phase diagram at finite density with four-flavor staggered\nfermions using the complex Langevin method, which is a promising approach to\novercome the sign problem. In our previous work on an $8^3 \\times 16$ lattice\nat $\\beta = 5.7$ with the quark mass $m = 0.01$, we have found that the baryon\nnumber density has a clear plateau as a function of the chemical potential. In\nthis study, we use a $16^3 \\times 32$ lattice to reduce finite volume effects\nand find that the plateau structure survives. Moreover, the number of quarks in\nthe plateau region turns out to be 24, which is exactly the same as the one\nobtained previously on the $8^3 \\times 16$ lattice. We provide a simple\ninterpretation of this number, which suggests that the Fermi sphere is starting\nto form.",
        "positive": "Monopole and vortex content of a meron pair: We investigate the monopole and vortex content of a meron pair by calculating\nthe points at which the transformation to the Laplacian Center Gauge is\nill-defined and by studying the behavior of Wilson loops. These techniques\nreveal complementary aspects of the vortex and monopole structure, including\nthe presence of closed monopole lines and closed vortex surfaces joining the\ntwo merons, and evidence for intersecting vortex surfaces at each meron."
    },
    {
        "anchor": "Applying the Wang-Landau Algorithm to Lattice Gauge Theory: We implement the Wang-Landau algorithm in the context of SU(N) lattice gauge\ntheories. We study the quenched, reduced version of the lattice theory and\ncalculate its density of states for N=20,30,40,50. We introduce a variant of\nthe original algorithm in which the weight function used in the update does not\nasymptote to a fixed function, but rather continues to have small fluctuations\nwhich enhance tunneling. We formulate a method to evaluate the errors in the\ndensity of states, and use the result to calculate the dependence of the\naverage action density and the specific heat on the `t Hooft coupling lambda.\nThis allows us to locate the coupling lambda_t at which a strongly first order\ntransition occurs in the system. For N=20 and 30 we compare our results to\nthose obtained using Ferrenberg-Swendsen multi-histogram reweighting and find\nagreement with errors of 0.2 % or less. Extrapolating our results to N=oo we\nfind 1/lambda_t = 0.3148(2). We remark on the significance of this result for\nthe validity of quenched large-$N$ reduction of SU(N) lattice gauge theories.",
        "positive": "Thermodynamic properties of QCD with two flavors of Wilson-type lattice\n  quarks: I report on a study of finite temperature QCD by the CP-PACS Collaboration\ntoward a precise determination of the equation of state with dynamical u,d\nquarks. Based on a systematic simulation using improved Wilson-type quarks on\nlattices with temporal size $N_t=4$ and 6, the energy density and pressure are\ncalculated as functions of temperature and renormalized light quark mass in the\nrange $T/T_c \\approx 0.7$--2.5 and $m_{\\rm PS}/m_{\\rm V} = 0.65$--0.95. Results\nfor $N_t=4$ are found to contain significant scaling violations, while results\nfor $N_t=6$ are suggested to be not far from the continuum limit. On the other\nhand, the quark mass dependence in the EOS turned out to be small for $m_{\\rm\nPS}/m_{\\rm V} \\simlt 0.8$."
    },
    {
        "anchor": "Conjecture about the QCD phase diagram: We present a phase diagram study of the O(4) model as an effective theory for\n2-flavor QCD. In the chiral limit, both theories perform spontaneous symmetry\nbreaking with isomorphic groups, which suggests that they belong to the same\nuniversality class. Since we are interested in high temperature, we further\nassume dimensional reduction to the 3d O(4) model, which implies topological\nsectors. According to Skyrme and others, the corresponding topological charge\nrepresents the baryon number. Hence the baryon chemical potential $\\mu_{B}$\nappears as an imaginary vacuum angle, which can be included in the lattice\nsimulations without any sign problem. We present simulation results for the\ncritical line in the chiral limit, and for the crossover in the presence of\nlight quark masses. The shapes of these lines are compatible with other\nconjectures, but up to about $\\mu_{B} \\approx 300$ MeV we do not find a\nCritical Endpoint, although there are indications for it to be near-by.",
        "positive": "Hadron Wavefunctions as a Probe of a Two Color Baryonic Medium: The properties of the ground state of two-color QCD at non-zero baryon\nchemical potential $\\mu$ present an interesting problem in strongly-interacting\ngauge theory; in particular the nature of the physically-relevant degrees of\nfreedom in the superfluid phase in the post-onset regime $\\mu>m_\\pi/2$ still\nneeds clarification. In this study we present evidence for in-medium effects at\nhigh $\\mu$ by studying the wavefunctions of mesonic and diquark states using\northodox lattice simulation techniques, made possible by the absence of a Sign\nProblem for the model with $N_f=2$. Our results show that beyond onset the\nspatial extent of hadrons decreases as $\\mu$ grows, and that the wavefunction\nprofiles are consistent with the existence of a dynamically-gapped Fermi\nsurface in this regime."
    },
    {
        "anchor": "Classical and Quantum Computing of Shear Viscosity for $2+1D$ SU(2)\n  Gauge Theory: We perform a nonperturbative calculation of the shear viscosity for\n$(2+1)$-dimensional SU(2) gauge theory by using the lattice Hamiltonian\nformulation. The retarded Green's function of the stress-energy tensor is\ncalculated from real time evolution via exact diagonalization of the lattice\nHamiltonian with a local Hilbert space truncation and the shear viscosity is\nobtained via the Kubo formula. When taking the continuum limit, we account for\nthe renormalization group flow of the coupling but no additional operator\nrenormalization. We find the ratio of the shear viscosity and the entropy\ndensity $\\frac{\\eta}{s}$ is consistent with a well-known holographic result\n$\\frac{1}{4\\pi}$ at several temperatures on a $4\\times4$ hexagonal lattice with\nthe local electric representation truncated at $j_{\\rm max}=\\frac{1}{2}$. We\nalso find the ratio of the spectral function and frequency\n$\\frac{\\rho^{xy}(\\omega)}{\\omega}$ exhibits a peak structure when the frequency\nis small.\n  Both the exact diagonalization method and simple matrix product state\nclassical simulation method beyond $j_{\\rm max}=\\frac{1}{2}$ on bigger lattices\nrequire exponentially growing resources. So we develop a quantum computing\nmethod to calculate the retarded Green's function and analyze various\nsystematics of the calculation including $j_{\\rm max}$ truncation and finite\nsize effects and Trotter errors. We test our quantum circuit on both the\nQuantinuum emulator and the IBM simulator for a small lattice and obtain\nresults consistent with the classical computing ones.",
        "positive": "Tensor lattice field theory with applications to the renormalization\n  group and quantum computing: We discuss the successes and limitations of statistical sampling for a\nsequence of models studied in the context of lattice QCD and emphasize the need\nfor new methods to deal with finite-density and real-time evolution. We show\nthat these lattice models can be reformulated using tensorial methods where the\nfield integrations in the path-integral formalism are replaced by discrete\nsums. These formulations involve various types of duality and provide exact\ncoarse-graining formulas which can be combined with truncations to obtain\npractical implementations of the Wilson renormalization group program. Tensor\nreformulations are naturally discrete and provide manageable transfer matrices.\nCombining truncations with the time continuum limit, we derive Hamiltonians\nsuitable to perform quantum simulation experiments, for instance using cold\natoms, or to be programmed on existing quantum computers. We review recent\nprogress concerning the tensor field theory treatment of non-compact scalar\nmodels, supersymmetric models, economical four-dimensional algorithms,\nnoise-robust enforcement of Gauss's law, symmetry preserving truncations and\ntopological considerations. We discuss connections with other tensor network\napproaches."
    },
    {
        "anchor": "Deriving confinement via RG decimations: We present the general framework and building blocks of a recent derivation\nof the fact that the SU(2) LGT is in a confining phase for all values of the\ncoupling $0 < \\beta < \\infty$, for space-time dimension $d \\leq 4$. The method\nemploys approximate but explicitly computable RG decimations that are shown to\nconstrain the exact partition function and order parameters from above and\nbelow, and flow from the weak to the strong coupling regime without\nencountering a fixed point.",
        "positive": "Truncated Overlap Fermions: the link between Overlap and Domain Wall\n  Fermions: In this talk I will emphasize the role of the Truncated Overlap Fermions in\nshowing the equivalence between the Domain Wall and Overlap Fermions up to an\nirrelevant factor in the fermionic integration measure. I will also show how\nDomain Wall type fermions with a finite number of flavors can be used to\naccelerate propagator calculations of their light partner in the infinite\nflavor limit."
    },
    {
        "anchor": "Spontaneous symmetry breaking in the O(4) scalar model on a lattice: The spontaneous symmetry breaking at zero temperature in the four-component\nfour-dimensional scalar $\\lambda \\phi^4_4$ model (the O(4) model) is\ninvestigated on a lattice for different values of the coupling constant\n$\\lambda$. A general method for dealing with such type dependence is developed.\nThe Goldstone modes are integrated out in the spherical coordinates in the\ninternal space of the scalar field by the saddle point method, and the initial\nfunctional integral of the model is reduced to an effective one-component\ntheory convenient for lattice investigations. The partition function of this\ntheory is calculated analytically in the static limit and demonstrates the\n$\\lambda$-dependence which is characteristic for distinguishing symmetry\nbreaking. Monte Carlo simulations are performed with the QCDGPU software\npackage on a HGPU cluster. It is shown that the symmetry is spontaneously\nbroken for $\\lambda>\\lambda_0 \\simeq 10^{-5}$. For smaller coupling values, the\nscalar field vanishes on a lattice, which can be interpreted as instability of\nthe homogeneous condensate or even instability of the model itself. The\ncritical value $\\lambda_0$ is independent of the lattice sizes $16^4$ and\n$32^4$ investigated.",
        "positive": "The spontaneous generation of magnetic fields at high temperature in\n  SU(2)-gluodynamics on a lattice: The spontaneous generation of the chromomagnetic field at high temperature is\ninvestigated in a lattice formulation of the SU(2)-gluodynamics. The procedure\nof studying this phenomenon is developed. The Monte Carlo simulations of the\nfree energy on the lattices 2 \\times 8^3, 2\\times 16^3 and 4 \\times 8^3 at\nvarious temperatures are carried out. The creation of the field is indicated by\nmeans of the \\chi^2-analysis of the data set accumulating 5-10 millions MC\nconfigurations. A comparison with the results of other approaches is done."
    },
    {
        "anchor": "Nucleon to Delta transition form factors with $N_F=2+1$ domain wall\n  fermions: We calculate the electromagnetic, axial and pseudo-scalar form factors of the\nNucleon to $\\Delta(1232)$ transition using two dynamical light degenerate\nquarks and a dynamical strange quark simulated with the domain wall fermion\naction. Results are obtained at lattice spacings $a = 0.114$ fm and $a=0.084$\nfm, with corresponding pion masses of $330$ MeV and $297$ MeV, respectively.\nHigh statistics measurements are achieved by utilizing the coherent sink\ntechnique. The dominant electromagnetic dipole form factor, the axial form\nfactors and the pseudo-scalar coupling are extracted to a good accuracy. This\nallows the investigation of the non-diagonal Goldberger-Treiman relation.\nParticular emphasis is given on the extraction of the sub-dominant\nelectromagnetic quadrupole form factors and their ratio to the dominant dipole\nform factor, $R_{EM}$ and $R_{SM}$, measured in experiment.",
        "positive": "Computation of the Heavy-Light Decay Constant using Non-relativistic\n  Lattice QCD: We report results on a lattice calculation of the heavy-light meson decay\nconstant employing the non-relativistic QCD approach for heavy quark and Wilson\naction for light quark. Simulations are carried out at $\\beta=6.0$ on a\n$16^3\\times 48$ lattice. Signal to noise ratio for the ground state is\nsignificantly improved compared to simulations in the static approximation,\nenabling us to extract the decay constant reliably. We compute the heavy-light\ndecay constant for several values of heavy quark mass and estimate the\nmagnitude of the deviation from the heavy mass scaling law $f_{P} \\sqrt{m_{P}}\n= const$. For the $B$ meson we find $f_{B} = 171\\pm 22^{+19}_{-45}$ MeV, while\nan extrapolation to the static limit yields $f_{B}^{static}$ = $297\\pm\n36^{+15}_{-30}$ MeV."
    },
    {
        "anchor": "The lattice gluon propagator in stochastic perturbation theory: We calculate loop contributions up to four loops to the Landau gauge gluon\npropagator in numerical stochastic perturbation theory. For different lattice\nvolumes we carefully extrapolate the Euler time step to zero for the Langevin\ndynamics derived from the Wilson action. The one-loop result for the gluon\npropagator is compared to the infinite volume limit of standard lattice\nperturbation theory.",
        "positive": "Prepotential Formulation of Lattice Gauge Theory: Within the Hamiltonian formulation of Lattice gauge theories, prepotentials,\nbelonging to the fundamental representation of the gauge group and defined\nlocally at each site of the lattice, enables us to construct local loop\noperators and loop states. We propose a set of diagrammatic rules for the\naction of local gauge invariant operators on arbitrary loop states. Moreover We\npropose a new set of fusion variables within the prepotential aproach suitable\nfor approaching the weak coupling limit."
    },
    {
        "anchor": "Thermodynamics of the QCD transition from lattice: We discuss recent developments in lattice QCD for the bulk thermodynamics of\nthe transition. We review the current status of the equation of state, the\npossible implications of a magnetic field and the fluctuations of conserved\ncharges, like the net electric charge or baryon number. We also show\npredictions for higher cumulants, which will be experimentally available in\nnear future.",
        "positive": "Hadronic Weak Interactions of Light Quarks: In this review, three subjects are discussed: a phenomenological application\nof lattice predictions to $K^0$--$\\bar K^0$ mixing in Super Symmetry; a\ndiscussion of the non-perturbative renormalization methods for four-fermion\noperators and a new approach to extract weak matrix elements in effective\ntheories denoted as OPE without OPE (operator product expansion without\noperator product expansion)"
    },
    {
        "anchor": "Absolute X-distribution and self-duality: Various models of QCD vacuum predict that it is dominated by excitations that\nare predominantly self-dual or anti-self-dual. In this work we look at the\ntendency for self-duality in the case of pure-glue SU(3) gauge theory using the\noverlap-based definition of the field-strength tensor. To gauge this property,\nwe use the absolute X-distribution method which is designed to quantify the\ndynamical tendency for polarization for arbitrary random variables that can be\ndecomposed in a pair of orthogonal subspaces.",
        "positive": "An exploratory lattice study of DI=3/2 K -> pi pi decays at\n  next-to-leading order in the chiral expansion: We present the first direct evaluation of DI = 3/2 K -> pi pi matrix elements\nwith the aim of determining all the low-energy constants at NLO in the chiral\nexpansion. Our numerical investigation demonstrates that it is indeed possible\nto determine the K -> pi pi matrix elements directly for the masses and momenta\nused in the simulation with good precision. In this range however, we find that\nthe matrix elements do not satisfy the predictions of NLO chiral perturbation\ntheory. For the chiral extrapolation we therefore use a hybrid procedure which\ncombines the observed polynomial behaviour in masses and momenta of our lattice\nresults, with NLO chiral perturbation theory at lower masses. In this way we\nfind stable results for the quenched matrix elements of the electroweak penguin\noperators (<pi pi (I=2)|O_8|K^0>= (0.68 +- 0.09) GeV^3 and <pi pi\n(I=2)|O_7|K^0>= (0.12 +- 0.02) GeV^3 in the NDR-MSbar scheme at the scale 2\nGeV), but not for the matrix elements of O_4 (for which there are too many\nLow-Energy Constants at NLO for a reliable extrapolation). For all three\noperators we find that the effect of including the NLO corrections is\nsignificant (typically about 30%). We present a detailed discussion of the\nstatus of the prospects for the reduction of the systematic uncertainties."
    },
    {
        "anchor": "Partially Quenched QCD with Non-Degenerate Dynamical Quarks: We discuss the importance of using partially quenched theories with three\ndegenerate quarks for extrapolating to QCD, and present some relevant results\nfrom chiral perturbation theory.",
        "positive": "Gluon propagator and zero-momentum modes in SU(2) lattice gauge theory: We investigate propagators in Lorentz (or Landau) gauge by Monte Carlo\nsimulations. In order to be able to compare with perturbative calculations we\nuse large $\\beta$ values. There the breaking of the Z(2) symmetry turns out to\nbe important for all of the four lattice directions. Therefore we make sure\nthat the analysis is performed in the correct state. We discus implications of\nthe gauge fixing mechanism and point out the form of the weak-coupling behavior\nto be expected in the presence of zero-momentum modes. Our numerical result is\nthat the gluon propagator in the weak-coupling limit is strongly affected by\nzero-momentum modes. This is corroborated in detail by our quantitative\ncomparison with analytical calculations."
    },
    {
        "anchor": "Blockspin transformation for finite temperature field theories with\n  gauge fields: A procedure is proposed to study QFT at zero or at finite temperature by a\nsequence of real space renormalization group (RG) or blockspin transformations.\nThey transform to effective theories on coarser and coarser lattices.The\nultimate aim is to compute constraint effective potentials, i.e. the free\nenergy as a function of suitable order parameters.From the free energy one can\nread off the thermodynamic behaviour of the theory, in particular the existence\nand nature of phase transitions. In a finite temperature QFT one begins with\neither one or a sequence of transformations which transform the original theory\ninto an effective theory on a three-dimensional lattice. Its effective action\nhas temperature dependent coefficients. Thereafter one may proceed with further\nblockspin transformations of the three-dimensional theory. Assuming a finite\nvolume, this can in principle be continued until one ends with a lattice with a\nsingle site. Its effective action is the constraint effective potential. In\neach RG-step, an integral over the high frequency part of the field has to be\nperformed. This is done perturbatively and requires the knowledge of bare\nfluctuation field propagators and of interpolation operators which enter into\nthe vertices. A detailed examination of these quantities is presented for\nscalar fields, abelian gauge fields and for Higgs fields, finite temperature is\nadmitted.",
        "positive": "The Kaon Bag Parameter at Physical Mass: We present preliminary results for the calculation of the Kaon Bag parameter\n$B_K$ in $N_f=2+1$ lattice QCD, using M\\\"obius Domain Wall Fermion ensembles\ngenerated by the RBC-UKQCD collaboration. This computation is done directly at\nphysical meson masses, so that we do not have to rely on chiral perturbation\ntheory or any other mass extrapolation. In parallel, the four-quark operator is\nrenormalised through the Rome-Southampton technique. Finally, we compare our\nvalue with previous results and draw some conclusions about the remaining\ndominant contributions in our error budget."
    },
    {
        "anchor": "Spectral Properties of Quarks at Finite Temperature in Lattice QCD: We analyze the quark spectral function above and below the critical\ntemperature for deconfinement and at finite momentum in quenched lattice QCD.\nIt is found that the temporal quark correlation function in the deconfined\nphase near the critical temperature is well reproduced by a two-pole ansatz for\nthe spectral function. The bare quark mass and momentum dependences of the\nspectral function are analyzed with this ansatz. In the chiral limit we find\nthat even near the critical temperature the quark spectral function has two\ncollective modes corresponding to the normal and plasmino excitations in the\nhigh temperature (T) limit. The pole mass of these modes at zero momentum,\nwhich should be identified to be the thermal mass of the quark, is\napproximately proportional to T in a rather wide range of T in the deconfined\nphase.",
        "positive": "Some more details of minimal-Landau-gauge Yang-Mills propagators: The propagators of the elementary degrees of freedom of\n(minimal-)Landau-gauge Yang-Mills theory have been a useful tool in various\ninvestigations. However, in lattice calculations they show severe dependencies\non lattice artifacts. This problem has been addressed for various subsets of\nlattice artifacts and various subsets of propagators over the time. Here, an\nextended study of all propagators in momentum space, and for the gluon also in\nposition space, as well as derived quantities like the running coupling, is\nprovided simultaneously for two, three, and four dimensions over one or more\norders of magnitude in both physical volume and lattice spacing, in lower\ndimensions also over more than two orders of magnitude for the gauge group\nSU(2). Most of the known qualitative results are confirmed, but two quantities\nalso indicate a slight, but possibly interesting deviation."
    },
    {
        "anchor": "Charmed baryon spectrum from lattice QCD near the physical point: We calculate the low-lying spectrum of charmed baryons in lattice QCD on the\n$32^3\\times64$, $N_f=2+1$ PACS-CS gauge configurations at the almost physical\npion mass of $\\sim 156$ MeV/c$^2$. By employing a set of interpolating\noperators with different Dirac structures and quark-field smearings for the\nvariational analysis, we extract the ground and first few excited states of the\nspin-$1/2$ and spin-$3/2$, singly-, doubly-, and triply-charmed baryons.\nAdditionally, we study the $\\Xi_c$-$\\Xi_c^\\prime$ mixing and the operator\ndependence of the excited states in a variational approach. We identify several\nstates that lie close to the experimentally observed excited states of the\n$\\Sigma_c$, $\\Xi_c$ and $\\Omega_c$ baryons, including some of the $\\Xi_c$\nstates recently reported by LHCb. Our results for the doubly- and\ntriply-charmed baryons are suggestive for future experiments.",
        "positive": "Fermion determinant and chiral anomaly on a finite lattice: The fermion determinant and the chiral anomaly of lattice Dirac operator D on\na finite lattice are investigated. The condition for D to reproduce correct\nchiral anomaly at each site of a finite lattice for smooth background gauge\nfields is that D possesses exact zero modes satisfying the Atiyah-Singer index\ntheorem. This is also the necessary condition for D to have correct fermion\ndeterminant (ratio) which plays the important role of incorporating dynamical\nfermions in the functional integral. We outline a scheme for dynamical fermion\nsimulation of lattice QCD with topologically proper D."
    },
    {
        "anchor": "String Tension from Monopoles in SU(2) Lattice Gauge Theory: The axis for Figure 2 was wrong. It has been fixed and the postscript file\nreplaced (The file was called comp.ps).",
        "positive": "Hadron Masses from the Valence Approximation to Lattice QCD: We evaluate pseudoscalar, vector, spin 1/2 and spin 3/2 baryon masses\npredicted by lattice QCD with Wilson quarks in the valence (quenched)\napproximation for a range of different values of lattice spacing, lattice\nvolume and quark mass. Extrapolating these results to physical quark mass, then\nto zero lattice spacing and infinite volume we obtain values for eight mass\nratios. We also determine the zero lattice spacing, infinite volume limit of an\nalternate set of five quantities found without extrapolation in quark mass.\nBoth sets of predictions differ from the corresponding observed values by\namounts consistent with the predicted quantities' statistical uncertainties."
    },
    {
        "anchor": "Integrating out lattice gauge fields: The sign problem is a major obstacle to our understanding of the phase\ndiagram of QCD at finite baryon density. Several numerical methods have been\nproposed to tackle this problem, but a full solution to the sign problem is\nstill elusive. Motivated by this problem and by recent advances in diagrammatic\nMonte Carlo methods, we find a new exact representation of the partition\nfunction of pure lattice gauge theory that contains no link variables. This\napproach can be easily extended to include staggered fermions, and results in a\ndiagrammatic representation of fermionic states as arrangements of monomers,\ndimers, and fermionic loops saturating the spacetime lattice. Our\nrepresentations are exact for any value of the lattice coupling, and extend\nprevious representations that are only valid in the strong coupling limit and\nat $O(\\beta)$. As a concrete example, we construct a monomer-dimer-loop\nrepresentation of compact lattice QED.",
        "positive": "The Vector Meson Mass in Chiral Effective Field Theory: A brief overview of Quantum Chromodynamics (QCD) as a non-Abelian gauge field\ntheory, including symmetries and formalism of interest, will precede a focused\ndiscussion on the use of an Effective Field Theory (EFT) as a low energy\nperturbative expansion technique. Regularization schemes involved in Chiral\nPerturbation Theory (\\c{hi}PT) will be reviewed and compared with EFT. Lattices\nwill be discussed as a useful procedure for studying large mass particles. An\nEffective Field Theory will be formulated, and the self energy of the \\r{ho}\nmeson for a Finite-Range Regulated (FRR) theory will be calculated. This will\nbe performed in both full QCD and the simpler quenched approximation (QQCD).\nFinite-volume artefacts, due to the finite box size on the lattice, will be\nquantified. Currently known lattice results will be used to calculate the\n\\r{ho} meson mass, and the possibility of unquenching will be explored. The aim\nof the research was to determine whether a stable unquenching procedure for the\n\\r{ho} meson could be discovered. The results from the original research\nindicate that there is no such procedure because the \\r{ho} mesons are\nunstable. Unless additional data involving lighter quark masses is available,\nan element of modelling is needed for successful unquenching."
    },
    {
        "anchor": "Pion spectral properties above the chiral crossover of QCD: Spectral functions encode a wealth of information about the dynamics of any\ngiven system, and the determination of their non-perturbative characteristics\nis a long-standing problem in quantum field theory. Whilst numerical\nsimulations of lattice QCD provide ample data for various Euclidean correlation\nfunctions, the inversion required to extract spectral functions is an ill-posed\nproblem. In this work, we pursue previously established constraints imposed by\nfield locality at finite temperature $T$, namely that spectral functions\npossess a non-perturbative representation which generalises the well-known\nK\\\"{a}ll\\'{e}n-Lehmann spectral form to $T>0$. Using this representation, we\nanalyse lattice QCD data of the spatial pseudo-scalar correlator in the\ntemperature range $220-960 \\, \\text{MeV}$, and obtain an analytic expression\nfor the corresponding spectral function, with parameters fixed by the data.\nFrom the structure of this spectral function we find evidence for the existence\nof a distinct pion state above the chiral pseudo-critical temperature\n$T_{\\text{pc}}$, and contributions from its first excitation, which gradually\nmelt as the temperature increases. As a non-trivial test, we find that the\nextracted spectral function reproduces the corresponding temporal lattice\ncorrelator data for $T=220 \\, \\text{MeV}$.",
        "positive": "Strangeness at high temperatures: from hadrons to quarks: Appropriate combinations of up to fourth order cumulants of net strangeness\nfluctuations and their correlations with net baryon number and electric charge\nfluctuations, obtained from lattice QCD calculations, have been used to probe\nthe strangeness carrying degrees of freedom at high temperatures. For\ntemperatures up to the chiral crossover separate contributions of strange\nmesons and baryons can be well described by an uncorrelated gas of hadrons.\nSuch a description breaks down in the chiral crossover region, suggesting that\nthe deconfinement of strangeness takes place at the chiral crossover. On the\nother hand, the strangeness carrying degrees of freedom inside the quark gluon\nplasma can be described by a weakly interacting gas of quarks only for\ntemperatures larger than twice the chiral crossover temperature. In the\nintermediate temperature window these observables show considerably richer\nstructures, indicative of the strongly interacting nature of the quark gluon\nplasma."
    },
    {
        "anchor": "Vector decay constants in quarkonia: Lattice NRQCD with leading finite lattice spacing errors removed is used to\nsimulate heavy-heavy vector decay constants. Quenched simulations are performed\nat three values of the coupling and fifteen values of the quark mass. The\nimproved gauge action with plaquettes and rectangles is used. Landau link\nimprovement is used throughout. \"Perturbative\" and nonperturbative meson masses\nare compared. One-loop perturbative matching between lattice and continuum\nheavy-heavy vector currents is performed. The data is consistent with the\nvector meson decay constant being proportional to the square root of its mass.",
        "positive": "The chiral condensate at large $N$: We present results for the large-$N$ limit of the chiral condensate computed\nfrom twisted reduced models. We followed a two-fold strategy, one constiting in\nextracting the condensate from the quark-mass dependence of the pion mass, the\nother consisting in extracting the condensate from the mode number of the Dirac\noperator."
    },
    {
        "anchor": "Vortex Content of SU(2) Calorons and Multi-Calorons: We use Laplacian Center Gauge to reveal the vortex content of single SU(2)\ncalorons and multi-caloron systems at different holonomies. The vortex surfaces\nin a single SU(2) caloron consist of two parts that are induced by the\nconstituent dyon charges and by the twist between the dyons, respectively. The\nlatter part percolates in a caloron ensemble at maximal nontrivial holonomy.\nThis finding fits perfectly in the confinement scenario of vortices and shows\nthat calorons are suitable to facilitate the vortex confinement mechanism.",
        "positive": "Algorithms for Dynamical Fermions: This is the write-up of three lectures on algorithms for dynamical fermions\nthat were given at the ILFTN workshop 'Perspectives in Lattice QCD' in Nara\nduring November 2005. The first lecture is on the fundamentals of Markov Chain\nMonte Carlo methods and introduces the Hybrid Monte Carlo (HMC) algorithm and\nsymplectic integrators; the second lecture covers topics in approximation\ntheory and thereby introduces the Rational Hybrid Monte Carlo (RHMC) algorithm\nand ways of evading integrator instabilities by means of multiple pseudofermion\nfields; the third lecture introduces on-shell chiral (Ginsparg-Wilson) lattice\nfermions and discusses five-dimensional formulations for computing fermion\npropagators for such fermions."
    },
    {
        "anchor": "A practical implementation of the Overlap-Dirac operator: A practical implementation of the Overlap-Dirac operator\n${{1+\\gamma_5\\epsilon(H)}\\over 2}$ is presented. The implementation exploits\nthe sparseness of $H$ and does not require full storage. A simple application\nto parity invariant three dimensional SU(2) gauge theory is carried out to\nestablish that zero modes related to topology are exactly reproduced on the\nlattice.",
        "positive": "Positive parity $D_s$ mesons: We study the positive parity charmed strange mesons using lattice QCD, the\nonly reliable ab initio method to study QCD at low energies. Especially the\nexperimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged\ntheory for quite some time. The dynamical lattice QCD simulations are performed\nat two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both\n$\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction\nof the correlation matrix in order to take into the account threshold effects.\nWhile the $J^P = 0^+$ channel benefited most from the inclusion of scattering\noperators, it was also crucial for the case of the $D_{s1}(2460)$. Using the\nL\\\"uscher method, which relates the finite volume spectrum to the infinite\nvolume scattering matrix, we were able to determine the near threshold behavior\nof the scattering amplitude. From it we extracted the binding momenta and the\nmasses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$\nby determining the pole positions of the scattering amplitudes. Our results\ncompare well with experiment, resolving a long standing discrepancy between\ntheory and experiment."
    },
    {
        "anchor": "Dynamical linke cluster expansions: Algorithmic aspects and applications: Dynamical linked cluster expansions are linked cluster expansions with\nhopping parameter terms endowed with their own dynamics. They amount to a\ngeneralization of series expansions from 2-point to point-link-point\ninteractions. We outline an associated multiple-line graph theory involving\nextended notions of connectivity and indicate an algorithmic implementation of\ngraphs. Fields of applications are SU(N) gauge Higgs systems within variational\nestimates, spin glasses and partially annealed neural networks. We present\nresults for the critical line in an SU(2) gauge Higgs model for the electroweak\nphase transition. The results agree well with corresponding high precision\nMonte Carlo results.",
        "positive": "Speed and Adaptability of Overlap Fermion Algorithms: We compare the efficiency of four different algorithms to compute the overlap\nDirac operator, both for the speed, i.e., time required to reach a desired\nnumerical accuracy, and for the adaptability, i.e., the scaling of speed with\nthe condition number of the (square of the) Wilson Dirac operator. Although\northogonal polynomial expansions give good speeds at moderate condition number,\nthey are highly non-adaptable. One of the rational function expansions, the\nZolotarev approximation, is the fastest and is adaptable. The conjugate\ngradient approximation is adaptable, self-tuning, and nearly as fast as the ZA."
    },
    {
        "anchor": "Strange quark contribution to nucleon form factors: We discuss methods for the calculation of disconnected diagrams and their\napplication to various form factors of the nucleon. In particular, we present\npreliminary results for the strange contribution to the scalar and axial form\nfactors, calculated with N_f=2 dynamical flavors of Wilson fermions on an\nanisotropic lattice.",
        "positive": "A Fast Algorithm for Lattice Hyperonic Potentials: We describe an efficient algorithm to compute a large number of baryon-baryon\ninteractions from $NN$ to $\\Xi\\Xi$ by means of HAL QCD method, which lays the\ngroundwork for the nearly physical point lattice QCD calculation with volume\n$(96a)^4\\approx$($8.2$fm)$^4$. Preliminary results of $\\Lambda N$ potential\ncalculated with quark masses corresponding to\n($m_{\\pi}$,$m_{K}$)$\\approx$(146,525)MeV are presented."
    },
    {
        "anchor": "Quarkonium mass splittings with Fermilab heavy quarks and 2+1 flavors of\n  improved staggered sea quarks: We present results from an ongoing lattice study of the lowest lying\ncharmonium and bottomonium level splittings using the Fermilab heavy quark\nformalism. Our objective is to test the performance of this action on\nMILC-collaboration ensembles of (2+1) flavors of light improved staggered\n(asqtad) quarks. Measurements are done on 16 ensembles with degenerate up and\ndown quarks of various masses, thus permitting a chiral extrapolation, and over\nlattice spacings ranging from 0.09 fm to 0.18 fm, thus permitting study of\nlattice-spacing dependence. We examine combinations of the mass splittings that\nare sensitive to components of the effective quarkonium potential.",
        "positive": "GPU-Based Conjugate Gradient Solver for Lattice QCD with Domain-Wall\n  Fermions: We present the first GPU-based conjugate gradient (CG) solver for lattice QCD\nwith domain-wall fermions (DWF). It is well-known that CG is the most\ntime-consuming part in the Hybrid Monte Carlo simulation of unquenched lattice\nQCD, which becomes even more computational demanding for lattice QCD with exact\nchiral symmetry. We have designed a CG solver for the general 5-dimensional DWF\noperator on NVIDIA CUDA architecture with mixed-precision, using the defect\ncorrection as well as the reliable updates algorithms. We optimize our\ncomputation by even-odd preconditioning in the 4D space-time lattice, plus\nseveral innovative techniques for CUDA kernels. For NVIDIA GeForce GTX 285/480,\nour CG solver attains 180/233 Gflops (sustained)."
    },
    {
        "anchor": "The CP-PACS Project and Lattice QCD Results: The aim of the CP-PACS project was to develop a massively parallel computer\nfor performing numerical research in computational physics with primary\nemphasis on lattice QCD. The CP-PACS computer with a peak speed of 614 GFLOPS\nwith 2048 processors was completed in September 1996, and has been in full\noperation since October 1996. We present an overview of the CP-PACS project and\ndescribe characteristics of the CP-PACS computer. The CP-PACS has been mainly\nused for hadron spectroscopy studies in lattice QCD. Main results in lattice\nQCD simulations are given.",
        "positive": "Results from overlap valence quarks on a twisted mass sea: We present results of lattice computations using overlap fermions on a\ntwisted mass background. $N_f=2$ full QCD gauge configurations have been\nproduced by the ETM Collaboration with very light pions (down to less than 300\nMeV), with small lattice spacing ($a \\approx 0.09$ fm) and large volumes\n($V/a^4=24^3\\times 48$). By profiting of the good chiral properties of the\noverlap operator for the valence quarks, it is also possible to have a precise\n(and unquenched) determination of those physical quantities where the chiral\nproperties are crucial. In order to have unquenched results, we match the\nvalence quark mass with the sea quark mass. We also perform computations with\ndifferent quark masses in order to simulate (partially quenched) Strange and\nCharm quarks. A typical application is the computation of $B_K$, for which we\npresent first results."
    },
    {
        "anchor": "BQCD - Berlin quantum chromodynamics program: We publish BQCD as free software under the GNU General Public License. BQCD\nis a Hybrid Monte-Carlo program that simulates lattice QCD with dynamical\nWilson fermions. It is one of the main production programs of the QCDSF\ncollaboration. The program can simulate 2 and 2 + 1 fermion flavours with pure,\nclover improved, and stout smeared fat link Wilson fermions as well as standard\nplaquette, and an improved (rectangle) gauge action. The single flavour is\nsimulated with the Rational Hybrid Monte-Carlo algorithm.",
        "positive": "Parton Distribution Functions from Ioffe time pseudo-distributions: In this paper, we present a detailed study of the unpolarized nucleon parton\ndistribution function (PDF) employing the approach of parton\npseudo-distribution functions. We perform a systematic analysis using three\nlattice ensembles at two volumes, with lattice spacings $a=$ 0.127 fm and $a=$\n0.094 fm, for a pion mass of roughly 400 MeV. With two lattice spacings and two\nvolumes, both continuum limit and infinite volume extrapolation systematic\nerrors of the PDF are estimated. In addition to the $x$ dependence of the PDF,\nwe compute their first two moments and compare them with the pertinent\nphenomenological determinations."
    },
    {
        "anchor": "Simulating the All-Order Strong Coupling Expansion I: Ising Model Demo: We investigate in some detail an alternative simulation strategy for lattice\nfield theory based on the so-called worm algorithm introduced by Prokof'ev and\nSvistunov in 2001. It amounts to stochastically simulating the strong coupling\nexpansion rather than the usual configuration sum. A detailed error analysis\nand an important generalization of the method are exemplified here in the\nsimple Ising model. It allows for estimates of the two point function where in\nspite of exponential decay the signal to noise ratio does not degrade at large\nseparation. Critical slowing down is practically absent. In the outlook some\nthoughts on the general applicability of the method are offered.",
        "positive": "Lattice study of nuclear forces: Recent progress of lattice QCD study of nuclear forces (potentials) is\nreviewed. Scattering phase shift is an important observable for two particle\nsystem. In lattice QCD, phase shifts are calculated from long distance behavior\nof Bethe-Salpeter (BS) wave functions by Luescher's finite volume method. For\napplications to nuclear physics of multi-nucleon system, it is more\nadvantageous to convert the information of phase shifts in the form of\npotentials. We therefore extend the method so as to generate the potentials\nfrom BS wave functions. These potentials are faithful to scattering phase shift\nby construction, because they can reproduce BS wave functions in which the\ninformation of phase shift is embeded in the long distance part.The method was\nfirst applied to the central potential in NN system. It is now applied to many\nobjects, such as tensor potential, hyperon potentials, energy dependence of\nnuclear potentials, and investigations of the repulsive core at short distance."
    },
    {
        "anchor": "Semileptonic B Decays from an NRQCD/D234 Action: Semileptonic B decays are studied on quenched anisotropic lattices using\nSymanzik improved glue, NRQCD heavy quark and D234 light quark actions. We\nemploy constrained fits to extract ground state contributions to two- and\nthree-point correlators. Results for the B --> pi, l nubar decay form factors\nare compared with previous lattice results. We find that our systematic errors\n(excluding quenching errors) are dominated by chiral extrapolation\nuncertainties.",
        "positive": "Unquenched Numerical Stochastic Perturbation Theory: The inclusion of fermionic loops contribution in Numerical Stochastic\nPerturbation Theory (NSPT) has a nice feature: it does not cost so much\n(provided only that an FFT can be implemented in a fairly efficient way).\nFocusing on Lattice SU(3), we report on the performance of the current\nimplementation of the algorithm and the status of first computations\nundertaken."
    },
    {
        "anchor": "Meson Screening Masses in (2+1)-Flavor QCD: We present lattice QCD results for mesonic screening masses in the\ntemperature range 140 MeV $\\lesssim T \\lesssim$ 2500 MeV. Our calculations were\ncarried out using (2+1)-flavors of the Highly Improved Staggered Quark (HISQ)\naction, with a physical value for the strange quark mass and two values of the\nlight quark mass corresponding to pion masses of 160 MeV and 140 MeV.\nContinuum-extrapolated results were obtained using calculations with a variety\nof lattice spacings corresponding to temporal lattice extents $N_\\tau = 6 -\n16$. We discuss the implications of these results for the effective restoration\nof various symmetries in the high temperature phase of QCD, as well as the\napproach toward the perturbative limit.",
        "positive": "Perturbative Renormalization Factors of Bilinear Quark Operators for\n  Improved Gluon and Quark Actions in Lattice QCD: We calculate one-loop renormalization factors of bilinear quark operators for\ngluon action including six-link loops and $O(a)$-improved quark action in the\nlimit of massless quark. We find that finite parts of one-loop coefficients of\nrenormalization factors diminish monotonically as either of the coefficients\n$c_1$ or $c_2+c_3$ of the six-link terms are decreased below zero. Detailed\nnumerical results are given, for general values of the clover coefficient, for\nthe tree-level improved gluon action in the Symanzik approach $(c_1=-1/12,\nc_2=c_3=0)$ and for the choices suggested by Wilson $(c_1=-0.252, c_2=0,\nc_3=-0.17)$ and by Iwasaki $(c_1=-0.331, c_2=c_3=0$ and $c_1=-0.27,\nc_2+c_3=-0.04)$ from renormalization-group analyses. Compared with the case of\nthe standard plaquette gluon action, finite parts of one-loop coefficients are\nreduced by 10--20% for the Symanzik action, and approximately by a factor two\nfor the renormalization-group improved gluon actions."
    },
    {
        "anchor": "Baryon Masses in Lattice QCD with Exact Chiral Symmetry: We investigate the baryon mass spectrum in quenched lattice QCD with exact\nchiral symmetry. For 100 gauge configurations generated with Wilson gauge\naction at $ \\beta = 6.1 $ on the $ 20^3 \\times 40 $ lattice, we compute\n(point-to-point) quark propagators for 30 quark masses in the range $ 67 {MeV}\n\\le m_q \\le 1790 {MeV} $. For baryons only composed of strange and charm\nquarks, their masses are extracted directly from the time correlation\nfunctions, while for those containing $ u (d) $ light quarks, their masses are\nobtained by chiral extrapolation to $ m_\\pi = 135 $ MeV. Our results of baryon\nmasses are in good agreement with experimental values, except for the negative\nparity states of $ \\Lambda $ and $ \\Lambda_c $. Further, our results of charmed\n(including doubly-charmed and triply-charmed) baryons can serve as predictions\nof QCD.",
        "positive": "Flavor Diagonal Nucleon Charges: This talk provides an update on the calculation of matrix elements of flavor\ndiagonal axial, scalar and tensor quark bilinear operators between the nucleon\nground state. The simulations are done using Wilson-clover fermions on a sea of\neight 2+1+1-flavor HISQ ensembles generated by the MILC collaboration. We\ndiscuss the signal in the connected and disconnected contributions, calculation\nof the renormalization constants and mixing in the RI-sMOM scheme, and control\nover the simultaneous chiral-continuum-finite-volume fit used to extract the\nfinal charges."
    },
    {
        "anchor": "The gradient flow running coupling with twisted boundary conditions: We study the gradient flow for Yang-Mills theories with twisted boundary\nconditions. The perturbative behavior of the energy density $\\langle\nE(t)\\rangle$ is used to define a running coupling at a scale given by the\nlinear size of the finite volume box. We compute the non-perturbative running\nof the pure gauge $SU(2)$ coupling constant and conclude that the technique is\nwell suited for further applications due to the relatively mild cutoff effects\nof the step scaling function and the high numerical precision that can be\nachieved in lattice simulations. We also comment on the inclusion of matter\nfields.",
        "positive": "On the finite size mass shift formula for stable particles: Luescher's finite size mass shift formula in a periodic finite volume,\ninvolving forward scattering amplitudes in the infinite volume, is revisited\nfor the two stable distinguishable particle system. The generalized mass shift\nformulae for the boson and fermion are derived in the boson-boson and\nfermion-boson systems, respectively. The nucleon mass shift formula is given in\nthe nucleon-pion system and the relation to the computation within chiral\nperturbation theory is discussed."
    },
    {
        "anchor": "Phase Transitions in Abelian Lattice Gauge Theory: Production and\n  Dissolution of Monopoles and Monopole-Antimonopole Pairs: We combine the microcanonical formulation of lattice gauge theories (LGTs)\ndeveloped by Callaway and the microcanonical inflection point analysis (MIPA)\nproposed by Bachmann et al. to achieve a systematic characterization of phase\ntransitions (PTs) in U(1) lattice electrodynamics. Besides identifying the\nwell-known deconfinement PT (DPT) due to the neutral pair dissolution, which we\nclassify as a first-order PT, we unequivocally detect three higher-order PTs.\nAccording to MIPA, we observe two independent third-order PTs in the confined\nphase; instead, in the deconfined (Coulomb) phase, we observe a dependent\nthird-order PT. For a deeper understanding of the physical meaning of these\nPTs, we numerically compute the average number density of monopolar and pair\ndefects as a function of energy. Our analysis reveals that DPT is only one of\nthe major mechanisms observable in LGT. The independent third-order PTs are\nassociated, respectively, to the first occurrence of monopolar topological\ndefects and to the production of pairs.",
        "positive": "Monopole characteristics in various Abelian gauges: Renormalization group (RG) smoothing is employed on the lattice to\ninvestigate and to compare the monopole structure of the SU(2) vacuum as seen\nin different gauges (maximally Abelian (MAG), Polyakov loop (PG) and Laplacian\ngauge (LG)). Physically relevant types of monopoles (LG and MAG) are\ndistinguished by their behavior near the deconfining phase transition. For the\nLG, Abelian projection reproduces well the gauge independent monopole structure\nencoded in an auxiliary Higgs field. Density and localization properties of\nmonopoles, their non-Abelian action and topological charge are studied. Results\nare presented confirming the Abelian dominance with respect to the\nnon-perturbative static potential for all gauges considered."
    },
    {
        "anchor": "Parity doubling in two-flavor SU(2) at high temperature: We study the mass spectrum of mesons at high temperature in $SU(2)$ gauge\ntheory with two flavors of Dirac fundamental fermions. Numerical simulations\nare carried out on anisotropic lattices using Wilson fermions, with lattice\nparameters tuned so that Euclidean symmetry is restored at low energy. We\ndetermine the pseudo-critical temperature $T_c$ using renormalized Polyakov\nloops. We calculate temporal and spatial meson correlation functions across\n$T_c$, and observe a clear sign of parity doublings above $T_c$ in both vector\nand scalar channels. The degeneracy between parity partners in the spectrum\nindicates that the enhanced $SU(4) \\times U(1)_A$ global symmetry of the model\nis restored at high temperature.",
        "positive": "Extraction of K-->pipi Matrix Elements with Wilson Fermions: We present the status of a lattice calculation for the K-->pipi matrix\nelements of the (delta S=1) effective weak Hamiltonian, directly with two pion\nin the final state. We study the energy shift of two pion in a finite volume\nboth in the I=0 and I=2 channels. We explain a method to avoid the Goldstone\npole contamination in the computation of renormalization constants for (delta\nI=3/2) operators. Finally we show some preliminary results for the matrix\nelements of (delta I=1/2) operators. Our quenched simulation is done at\nbeta=6.0, with Wilson fermions, on a (24^3 X 64) lattice."
    },
    {
        "anchor": "Renormalization constants for Lattice QCD: new results from Numerical\n  Stochastic Perturbation Theory: By making use of Numerical Stochastic Perturbation Theory (NSPT) we can\ncompute renormalization constants for Lattice QCD to high orders, e.g. three or\nfour loops for quark bilinears. We report on the status of our computations,\nwhich provide several results for Wilson quarks and in particular (values\nand/or ratios of) Z_V, Z_A, Z_S, Z_P. Results are given for various number of\nflavors (n_f = 0, 2, 3, 4). While we recall the care which is due for the\ncomputation of quantities for which an anomalous dimension is in place, we\npoint out that our computational framework is well suited to a variety of other\ncalculations and we briefly discuss the application of NSPT to other\nregularizations (in particular the Clover action).",
        "positive": "On the index theorem for Wilson fermions: We consider a Wilson-Dirac operator with improved chiral properties. We show\nthat, for arbitrarily rough gauge fields, it satisfies the index theorem if we\nidentify the zero modes with the small real eigenvalues of the fermion operator\nand use the geometrical definition of topological charge. This is also\nconfirmed in a numerical study of the quenched Schwinger model. These results\nsuggest that integer definitions of the topological charge based on counting\nreal modes of the Wilson operator are equivalent to the geometrical definition.\nThe problem of exceptional configurations and the sign problem in simulations\nwith an odd number of dynamical Wilson fermions are briefly discussed."
    },
    {
        "anchor": "Critical behaviour in QCD at finite isovector chemical potential: We report an investigation of criticality in QCD at finite isovector chemical\npotential, mu_3, and at zero temperature. At the critical point, mu_3^c = m_pi,\nwe find that an uncharged scalar and pseudoscalar and a charged pseudoscalar\nmeson become massless within the resolution of our measurement. The effective\nlong distance theory therefore breaks O(4) symmetry by charged pion\ncondensation. This results in a rising quark number susceptibility. The baryon\nremains massive, as indicated by a vanishing baryon number susceptibility.",
        "positive": "Nonperturbative running of the tensor operator for $N_\\rm{f}=3$ QCD from\n  the chirally rotated Schr\u00f6dinger Functional: We study the Renormalisation Group (RG) running of the non-singlet tensor\noperator, for $N_\\mathrm{\\scriptstyle f}=3$ QCD with Wilson fermions in a mixed\naction setup, with standard Schr\\\"odinger Functional (SF) boundary conditions\nfor sea quarks and chirally rotated Schr\\\"odinger Functional ($\\chi$SF)\nboundary conditions for valence quarks. Based on a recursive finite-size\nscaling technique we compute non-perturbatively the tensor step-scaling\nfunction for an energy range between a hadronic scale and an electroweak scale,\nabove which perturbation theory may be safely applied. Our result is expressed\nas the RG-running factor $T^{\\mathrm{RGI}}/[\nT(\\mu_{\\mathrm{had}})]_{\\scriptstyle \\rm R}$, where the numerator is the scale\nindependent (Renormalisation Group Invariant - RGI) tensor operator and the\ndenominator is its renormalised counterpart at a hadronic scale\n$\\mu_{\\mathrm{had}} = 233(8)$~MeV in a given scheme. We determine the\nstep-scaling function in four distinct renormalisation schemes. We also compute\nthe renormalisation parameters of these schemes at $\\mu_{\\mathrm{had}}$ which,\ncombined with the RG-running factor, gives the scheme-independent quantity\n$Z^{\\mathrm{RGI}}_{\\mathrm T}(g_0^2)$ in four schemes and for a range of bare\ngauge couplings in which large volume hadronic matrix element simulations are\nperformed by the CLS consortium in $N_\\mathrm{\\scriptstyle f}=2+1$ QCD. All\nfour results are compatible and also agree with a recent determination based on\na unitary setup for Wilson quarks with Schr\\\"odinger Functional boundary\nconditions~arXiv:2309.04314 . This provides a strong universality test."
    },
    {
        "anchor": "Improving chiral property of domain-wall fermions by reweighting method: The reweighting method is applied to improve the chiral property of\ndomain-wall fermions. One way to achieve this is to enlarge $L_s$, the size of\nfifth dimension, which controls the size of the induced chiral symmetry\nbreaking. While this is a type of reweighting method for shifting the action\nparameter, it seems non-trivial since this reweighting means change of the five\ndimensional lattice volume. In this report, we address issues in this direction\nof reweighting and evaluate its effectiveness.",
        "positive": "A gauge-invariant, rotor Hamiltonian from dual variables of 3D U(1)\n  gauge theory: We present a tensor formulation for free compact electrodynamics in three\nEuclidean dimensions and use this formulation to construct a quantum\nHamiltonian in the continuous-time limit. Gauge-invariance is maintained at\nevery step and the resulting Hamiltonian can be written as a rotor model. The\nenergy eigenvalues for this Hamiltonian are computed using the tensor\nformulation, and compared with perturbation theory. We find good agreement\nbetween the calculations demonstrating a smooth passage from the statistical\nlattice Lagrangian description to the quantum Hamiltonian description."
    },
    {
        "anchor": "New approximate solutions of the Ginsparg-Wilson equation - tests in 2-d: A new method for finding approximate solutions of the Ginsparg-Wilson\nequation is tested in 2-d. The Dirac operator is first constructed and then\nused in a dynamical simulation of the 2-flavor Schwinger model. We find a very\nsmall mass of the pi-particle implying almost chirally symmetric fermions. The\ngeneralization of our method to 4-d is straightforward.",
        "positive": "The energy-dependent $\u03c0^+ \u03c0^+ \u03c0^+$ scattering amplitude from QCD: Focusing on three-pion states with maximal isospin ($\\pi^+\\pi^+\\pi^+$), we\npresent the first non-perturbative determination of an energy-dependent\nthree-hadron scattering amplitude from first-principles QCD. The calculation\ncombines finite-volume three-hadron energies, extracted using numerical lattice\nQCD, with a relativistic finite-volume formalism, required to interpret the\nresults. To fully implement the latter, we also solve integral equations that\nrelate an intermediate three-body K matrix to the physical three-hadron\nscattering amplitude. The resulting amplitude shows rich analytic structure and\na complicated dependence on the two-pion invariant masses, represented here via\nDalitz-like plots of the scattering rate."
    },
    {
        "anchor": "Lattice N=4 super Yang-Mills at Strong Coupling: In this paper we present results from numerical simulations of N=4 super\nYang-Mills for two color gauge theory over a wide range of 't Hooft coupling\n$0<\\lambda\\le 30$ using a supersymmetric lattice action\n\\cite{Catterall:2009it}. Numerical study of this lattice theory has been\nstymied until recently by both sign problems and the occurrence of lattice\nartifact phases at strong coupling. We have recently developed a new action\nthat appears capable of solving both problems. The resulting action possesses\njust $SU(2)$ rather than $U(2)$ gauge symmetry. By explicit computations of the\nfermion Pfaffian we present evidence that the theory possesses no sign problem\nand exists in a single phase out to arbitrarily strong coupling. Furthermore,\npreliminary work shows that the logarithm of the supersymmetric Wilson loop\nvaries as the square root of the 't Hooft coupling $\\lambda$ for large\n$\\lambda$ in agreement with holographic predictions.",
        "positive": "Real--time dynamics of a hot Yang-Mills theory: a numerical analysis: We discuss recent results obtained from simulations of high temperature,\nclassical, real time dynamics of SU(2) Yang-Mills theory at temperatures of the\norder of the electroweak scale. Measurements of gauge covariant and gauge\ninvariant autocorrelations of the fields indicate that the ASY-Bodecker\nscenario is irrelevant at these temperatures."
    },
    {
        "anchor": "Yang-Lee zeros of a random matrix model for QCD at finite density: We study the Yang-Lee zeros of a random matrix partition function with the\nglobal symmetries of the QCD partition function. We consider both zeros in the\ncomplex chemical potential plane and in the complex mass plane. In both cases\nwe find that the zeros are located on a curve. In the thermodynamic limit, the\nzeros appear to merge to form a cut. The shape of this limiting curve can be\nobtained from a saddle-point analysis of the partition function. An explicit\nsolution for the line of zeros in the complex chemical potential plane at zero\nmass is given in the form of a transcendental equation.",
        "positive": "Wigner Functions on a Lattice: The Wigner functions on the one dimensional lattice are studied. Contrary to\nthe previous claim in literature, Wigner functions exist on the lattice with\nany number of sites, whether it is even or odd. There are infinitely many\nsolutions satisfying the conditions which reasonable Wigner functions should\nrespect. After presenting a heuristic method to obtain Wigner functions, we\ngive the general form of the solutions. Quantum mechanical expectation values\nin terms of Wigner functions are also discussed."
    },
    {
        "anchor": "The Charge and Matter radial distributions of Heavy-Light mesons\n  calculated on a lattice with dynamical fermions: A knowledge of the radial distributions of quarks inside hadrons could lead\nto a better understanding of the QCD description of these hadrons and possibly\nsuggest forms for phenomenological models. As a step in this direction, in an\nearlier work, the charge (vector) and matter (scalar) radial distributions of\nheavy-light mesons were measured in the quenched approximation on a 16^3x24\nlattice with a lattice spacing of 'a' approx. 0.17 fm, and a hopping parameter\ncorresponding to a light quark mass about that of the strange quark.\n  Here several improvements are now made: 1) The configurations are generated\nusing dynamical fermions with a approx 0.14 fm; 2) Many more gauge\nconfigurations areincluded; 3) The distributions at many off-axis, in addition\nto on-axis, points are measured; 4) The data analysis is much more complete. In\nparticular, distributions involving excited states are extracted.\n  The exponential decay of the charge and matter distributions can be described\nby mesons of mass 0.9 +- 0.1 and 1.5 +- 0.1 GeV respectively -- values that are\nconsistent with those of vector and scalar $q\\bar{q}$-states calculated\ndirectly with the same lattice parameters.",
        "positive": "Blocking of lattice monopoles from the continuum in hot lattice\n  gluodynamics: The Abelian monopoles in lattice gluodynamics are associated with continuum\nmonopoles blocked to the lattice. This association allows to predict the\nlattice monopole action and density of the (squared) monopole charges from a\ncontinuum monopole model. The method is applied to the static monopoles in high\ntemperature gluodynamics. We show that the numerical data both for the density\nand the action of the lattice monopoles can be described in terms of a Coulomb\ngas of Abelian monopoles in the continuum."
    },
    {
        "anchor": "Pion scattering in Wilson ChPT: We compute the scattering amplitude for pion scattering in Wilson chiral\nperturbation theory for two degenerate quark flavors. We consider two different\nregimes where the quark mass m is of order (i) a\\Lambda_QCD^2 and (ii)\na^2\\Lambda_QCD^3. Analytic expressions for the scattering lengths in all three\nisospin channels are given. As a result of the O(a^2) terms the I=0 and I=2\nscattering lengths do not vanish in the chiral limit. Moreover, additional\nchiral logarithms proportional to a^2\\ln M_{\\pi}^2 are present in the one-loop\nresults for regime (ii). These contributions significantly modify the familiar\nresults from continuum chiral perturbation theory.",
        "positive": "Mean field analysis of the SO(3) lattice gauge theory at finite\n  temperature: We study the finite temperature properties of the SO(3) lattice gauge theory\nusing mean field theory. The main result is the calculation of the effective\naction at finite temperature. The form of the effective action is used to\nexplain the behaviour of the adjoint Wilson line in numerical simulations.\nNumerical simulations of the SO(3) lattice gauge theory show that the adjoint\nWilson line has a very small value at low temperatures; at high temperatures,\nmetastable states are observed in which the adjoint Wilson line takes positive\nor negative values. The effective action is able to explain the origin of these\nmetastable states. A comparison of the effective actions of the SU(2) and the\nSO(3) lattice gauge theories explains their different behaviour at high\ntemperatures. The mean field theory also predicts a finite temperature phase\ntransition in the SO(3) lattice gauge theory."
    },
    {
        "anchor": "Flavor structure of the baryon-baryon interaction from lattice QCD: We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD\nsimulations with degenerate quark masses for all flavors. The BB potentials in\nthe orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions\nmeasured on the lattice. We observe strong flavor-spin dependences of the BB\npotentials at short distances. In particular, a strong repulsive core exists in\nthe flavor-octet and spin-singlet channel(the 8_s representation), while an\nattractive core appears in the flavor singlet channel (the 1 representation).\nWe discuss the relation of such flavor-spin dependence with the Pauli exclusion\nprinciple at the quark level. The possible existence of an H-dibaryon resonance\nabove the Lambda-Lambda threshold is also discussed.",
        "positive": "Axial U(1) symmetry near the pseudocritical temperature in $N_f=2+1$\n  lattice QCD with chiral fermions: We study the $U(1)_A$ anomaly at high temperatures of $N_f=2+1$ lattice QCD\nwith chiral fermions. Gauge ensembles are generated with M\\\"obius domain-wall\n(MDW) fermions, and the measurements are reweighted to those with overlap\nfermions. We report on the results for the Dirac spectra, the $U(1)_A$\nsusceptibility, and the topological susceptibility in the temperature range of\n$T=136$, $153$, $175$, and $204$ MeV, where the up and down quark masses are\nset to be near the physical point as well as at lighter or heavier masses."
    },
    {
        "anchor": "Non-perturbative decoupling of massive fermions: SU(2) gauge theory with Nf=24 massless fermions is non-interacting at long\ndistances, i.e. it has an infrared fixed point at vanishing coupling. With\nmassive fermions the fermions are expected to decouple at energy scales below\nthe fermion mass, and the infrared behaviour is that of confining SU(2) pure\ngauge theory. We demonstrate this behaviour non-perturbatively with lattice\nMonte Carlo simulations by measuring the gradient flow running coupling.",
        "positive": "The Tunneling Hybrid Monte-Carlo algorithm: The hermitian Wilson kernel used in the construction of the domain-wall and\noverlap Dirac operators has exceptionally small eigenvalues that make it\nexpensive to reach high-quality chiral symmetry for domain-wall fermions, or\nhigh precision in the case of the overlap operator. An efficient way of\nsuppressing such eigenmodes consists of including a positive power of the\ndeterminant of the Wilson kernel in the Boltzmann weight, but doing this also\nsuppresses tunneling between topological sectors. Here we propose a\nmodification of the Hybrid Monte-Carlo algorithm which aims to restore\ntunneling between topological sectors by excluding the lowest eigenmodes of the\nWilson kernel from the molecular-dynamics evolution, and correcting for this at\nthe accept/reject step. We discuss the implications of this modification for\nthe acceptance rate."
    },
    {
        "anchor": "Equation of state of a relativistic theory from a moving frame: We propose a new strategy for determining the equation of state of a\nrelativistic thermal quantum field theory by considering it in a moving\nreference system. In this frame an observer can measure the entropy density of\nthe system directly from its average total momentum. In the Euclidean path\nintegral formalism, this amounts to compute the expectation value of the\noff-diagonal components T_{0k} of the energy-momentum tensor in presence of\nshifted boundary conditions. The entropy is thus easily measured from the\nexpectation value of a local observable computed at the target temperature T\nonly. At large T, the temperature itself is the only scale which drives the\nsystematic errors, and the lattice spacing can be tuned to perform a reliable\ncontinuum limit extrapolation while keeping finite-size effects under control.\nWe test this strategy for the four-dimensional SU(3) Yang-Mills theory. We\npresent precise results for the entropy density and its step-scaling function\nin the temperature range 0.9 T_c - 20 T_c. At each temperature, we consider\nfour lattice spacings in order to extrapolate the results to the continuum\nlimit. As a byproduct we also determine the ultraviolet finite renormalization\nconstant of T_{0k} by imposing suitable Ward identities. These findings\nestablish this strategy as a solid, simple and efficient method for an accurate\ndetermination of the equation of state of a relativistic thermal field theory\nover several orders of magnitude in T.",
        "positive": "Lattice QCD study of static quark and antiquark correlations via\n  entanglement entropies: We study the color correlation between static quark and antiquark ($q\\bar q$)\nin the confined phase via reduced density matrices $\\rho$ defined in color\nspace. We adopt the standard Wilson gauge action and perform quenched\ncalculations with the Coulomb gauge condition for reduced density matrices. The\nspatial volumes are $L^3 = 8^3$, $16^3$, $32^3$ and $48^3$, with the gauge\ncouplings $\\beta = 5.7$, 5.8 and 6.0. Each element of the reduced density\nmatrix in the sub space of quarks' color degrees of freedom of the $q\\bar q$\npair is calculated from staples defined by link variables. As a result, we find\nthat $\\rho$ is well written by a linear combination of the strongly correlated\n$q\\bar q$ pair state with the color-singlet component and the uncorrelated\n$q\\bar q$ pair state with random color configurations. We compute the Renyi\nentropies $S^{\\rm Renyi}$ from $\\rho$ to investigate the $q\\bar q$ distance\ndependence of the color correlation of the $q\\bar q$ pair and find that the\ncolor correlation is quenched as the distance increases."
    },
    {
        "anchor": "On the nature of an excited state: In many lattice simulations with dynamical quarks, radial or orbital\nexcitations of hadrons lie near multihadron thresholds: it makes the extraction\nof excited states properties more challenging and can introduce some\nsystematics difficult to estimate without an explicit computation of\ncorrelators using interpolating fields strongly coupled to multihadronic\nstates. In a recent study of the strong decay of the first radial excitation of\nthe $B^*$ meson, this issue has been investigated and we have clues that a\ndiquark interpolating field $\\bar{b} \\gamma^i q$ is very weakly coupled to a $B\n\\pi$ $P$-wave state while the situation is quite different if we consider an\ninterpolating field of the kind $\\bar{b} \\nabla^i q$, where $\\vec{\\nabla}$ is a\ncovariant derivative: those statements are based on examining the charge\ndensity distribution.",
        "positive": "Dual formulations of non-abelian spin models: local representation and\n  low-temperature asymptotics: Non-abelian lattice spin models with symmetry group SU(N) or U(N) can be\nformulated in terms of link variables which are subject to the Bianchi\nconstraints. Using this representation we derive exact and local dual\nformulation for the partition function of such models on a cubic lattice in\narbitrary dimension D. Locality means that the dual action is given by a sum\nover some subset of hypercubes of the dual lattice and the interaction between\ndual variables ranges over one given hypercube. Dual variables are in general\ndiscrete-valued and live on (D-2)-cell of the dual lattice, in close analogy\nwith the XY model. We use our construction to study in details the dual of\nSU(2) principal chiral model in two dimensions. We give dual expressions also\nfor two-point correlation function in arbitrary representation and for the free\nenergy of defects. Leading terms of the asymptotic expansion of the dual\nBoltzmann factor are computed and it is proven that at low temperatures it\nconverges to a certain Gaussian distribution uniformly in all fluctuations of\ndual variables. This result enables us to define the semiclassical limit of the\ndual formulation and to determine an analog of the vortex--spin-wave\nrepresentation for the partition function. Such representation is used to\nextract leading perturbative contribution to the correlation function which\nshows power-like decay at weak coupling. We also present some analytical\nevidences that the low-temperature limit of the dual formulation is completely\ndescribed by ISO(2)-like approximation of SU(2) matrix elements."
    },
    {
        "anchor": "Insights into the heavy dense QCD phase diagram using Complex Langevin\n  simulations: Complex Langevin simulations provide an alternative to sample path integrals\nwith complex weights and therefore are suited to determine the phase diagram of\nQCD from first principles. Adaptive step-size scaling and gauge cooling are\nused to improve the convergence of our simulations. We present results for the\nphase diagram of QCD in the limit of heavy quarks and discuss the order of the\nphase transitions, which are studied by varying the spatial simulation volume.",
        "positive": "On Lattice Computations of K+ --> pi+ pi0 Decay at m_K =2m_pi: We use one-loop chiral perturbation theory to compare potential lattice\ncomputations of the K+ --> pi+ pi0 decay amplitude at m_K=2m_pi with the\nexperimental value. We find that the combined one-loop effect due to this\nunphysical pion to kaon mass ratio and typical finite volume effects is still\nof order minus 20-30%, and appears to dominate the effects from quenching."
    },
    {
        "anchor": "Chiral condensate and Dirac spectrum of one- and two-flavor QCD at\n  nonzero $\u03b8$-angle: In the $\\epsilon$-domain of QCD we have obtained exact analytical expressions\nfor the eigenvalue density of the Dirac operator at fixed $\\theta \\ne 0$ for\nboth one and two flavors. These results made it possible to explain how the\ndifferent contributions to the spectral density conspire to give a chiral\ncondensate at fixed $\\theta$ that does not change sign when the quark mass (or\none of the quark masses for two flavors) crosses the imaginary axis, while the\nchiral condensate at fixed topological charge does change sign. From QCD at\nnonzero density we have learnt that the discontinuity of the chiral condensate\nmay move to a different location when the spectral density increases\nexponentially with the volume with oscillations on the order of the inverse\nvolume. This is indeed what happens when the product of the quark masses\nbecomes negative, but the situation is more subtle in this case: the\ncontribution of the \"quenched\" part of the spectral density diverges in the\nthermodynamic limit at nonzero $\\theta$, but this divergence is canceled\nexactly by the contribution from the zero modes. We conclude that the zero\nmodes are essential for the continuity of the chiral condensate and that their\ncontribution has to be perfectly balanced against the contribution from the\nnonzero modes. Lattice simulations at nonzero $\\theta$-angle can only be\ntrusted if this is indeed the case.",
        "positive": "Quark propagator at finite temperature and finite momentum in quenched\n  lattice QCD: We present an analysis of the quark spectral function above and below the\ncritical temperature for deconfinement performed at zero and non-zero momentum\nin quenched lattice QCD using clover improved Wilson fermions in Landau gauge.\nIt is found that the temporal quark correlation function in the deconfined\nphase near the critical temperature is well reproduced by a two-pole ansatz for\nthe spectral function. This indicates that excitation modes of the quark field\nhave small decay rates. The bare quark mass and momentum dependence of the\nspectral function is analyzed with this ansatz. In the chiral limit we find\nthat the quark spectral function has two collective modes corresponding to the\nnormal and plasmino excitations in the high temperature limit. Over a rather\nwide temperature range in the deconfined phase the pole mass of these modes at\nzero momentum, which corresponds to the thermal mass of the quark, is\napproximately proportional to temperature. With increasing bare quark masses\nthe plasmino mode gradually disappears and the spectral function is dominated\nby a single pole. We also discuss quasi-particle properties of heavy quarks in\nthe deconfined phase. In the confined phase, it is found that the pole ansatz\nfor the spectral function fails completely."
    },
    {
        "anchor": "Non-singlet quark helicity PDFs of the nucleon from pseudo-distributions: The non-singlet helicity quark parton distribution functions (PDFs) of the\nnucleon are determined from lattice QCD, by jointly leveraging\npseudo-distributions and the distillation spatial smearing paradigm. A Lorentz\ndecomposition of appropriately isolated space-like matrix elements reveals\npseudo-distributions that contain information on the leading-twist helicity\nPDFs, as well as an invariant amplitude that induces an additional $z^2$\ncontamination of the leading-twist signal. An analysis of the short-distance\nbehavior of the space-like matrix elements using matching coefficients computed\nto next-to-leading order (NLO) exposes the desired PDF up to this additional\n$z^2$ contamination. Due to the non-conservation of the axial current, we elect\nto isolate the helicity PDFs normalized by the nucleon axial charge at the same\nscale $\\mu^2$. The leading-twist helicity PDFs as well as several sources of\nsystematic error, including higher-twist effects, discretization errors, and\nthe aforementioned $z^2$ contaminating amplitude are jointly determined by\ncharacterizing the computed pseudo-distribution in a basis of Jacobi\npolynomials. The Akaike Information Criterion is exploited to effectively\naverage over distinct model parameterizations and cuts on the\npseudo-distribution. Encouraging agreement is observed with recent global\nanalyses of each non-singlet quark helicity PDF, notably a rather small\nnon-singlet anti-quark helicity PDF for all quark momentum fractions.",
        "positive": "Study of 3-dimensional SU(2) gauge theory with adjoint Higgs as a model\n  for cuprate superconductors: We study a 3-dimensional SU(2) gauge theory with 4 Higgs fields which\ntransform under the adjoint representation of the gauge group, that has been\nrecently proposed by Sachdev et al. to explain the physics of cuprate\nsuperconductors near optimal doping. The symmetric confining phase of the\ntheory corresponds to the usual Fermi-liquid phase while the broken (Higgs)\nphase is associated with the interesting pseudogap phase of cuprates. We employ\nthe Hybrid Monte-Carlo algorithm to study the phase diagram of the theory. We\nfind the existence of a variety of broken phases in qualitative accordance with\nearlier mean-field predictions and discuss their role in cuprates. In addition,\nwe investigate the behavior of Polyakov loop to probe the\nconfinement/deconfinement phase transition, and find that the Higgs phase hosts\na stable deconfining phase consistent with previous studies."
    },
    {
        "anchor": "First moments of the nucleon generalized parton distributions from\n  lattice QCD: We report on our lattice calculations of the nucleon's generalized parton\ndistributions (GPDs), concentrating on their first moments for the case of\nN_f=2. Due to recent progress on the numerical side we are able to present\nresults for the generalized form factors at pion masses as low as 260 MeV. We\nperform a fit to one-loop covariant baryon chiral perturbation theory with\nencouraging results.",
        "positive": "Improved Sampling Algorithms in Lattice QCD: Reverse Monte Carlo (RMC) is an algorithm that incorporates stochastic\nmodification of the action as part of the process that updates the fields in a\nMonte Carlo simulation. Such update moves have the potential of lowering or\neliminating potential barriers that may cause inefficiencies in exploring the\nfield configuration space. The highly successful Cluster algorithms for spin\nsystems can be derived from the RMC framework. In this work we apply RMC ideas\nto pure gauge theory, aiming to alleviate the critical slowing down observed in\nthe topological charge evolution as well as other long distance observables. We\npresent various formulations of the basic idea and report on our numerical\nexperiments with these algorithms."
    },
    {
        "anchor": "Lattice calculation of the HVP contribution to the anomalous magnetic\n  moment of muon: We report our (HPQCD) progress on the calculation of the Hadronic Vacuum\nPolarisation contribution to the anomalous magnetic moment of muon. In this\narticle we discuss the calculations for the light (up/down) quark connected\ncontribution using our method described in Phys.Rev. D89(2014) 11, 114501 and\ngive an estimate for the disconnected contribution. Our calculation has been\ncarried out on MILC Collaboration's $n_f = 2+1+1$ HISQ ensembles at multiple\nvalues of the lattice spacing, multiple volumes and multiple light sea quark\nmasses (including physical pion mass configurations).",
        "positive": "The chirally rotated Schr\u00f6dinger functional with Wilson fermions and\n  automatic O(a) improvement: A modified formulation of the Schr\\\"odinger functional (SF) is proposed. In\nthe continuum it is related to the standard SF by a non-singlet chiral field\nrotation and therefore referred to as the chirally rotated SF ($\\chi$SF). On\nthe lattice with Wilson fermions the relation is not exact, suggesting some\ninteresting tests of universality. The main advantage of the $\\chi$SF consists\nin its compatibility with the mechanism of automatic O($a$) improvement. In\nthis paper the basic set-up is introduced and discussed. Chirally rotated SF\nboundary conditions are implemented on the lattice using an orbifold\nconstruction. The lattice symmetries imply a list of counterterms, which\ndetermine how the action and the basic fermionic two-point functions are\nrenormalised and O($a$) improved. As with the standard SF, a logarithmically\ndivergent boundary counterterm leads to a multiplicative renormalisation of the\nfermionic boundary fields. In addition, a finite dimension 3 boundary\ncounterterm must be tuned in order to preserve the chirally rotated boundary\nconditions in the interacting theory. Once this is achieved, O($a$) effects\noriginating from the bulk action or from insertions of composite operators in\nthe bulk can be avoided by the mechanism of automatic O($a$) improvement. The\nremaining O($a$) effects arise from the boundaries and can be cancelled by\ntuning a couple of O($a$) boundary counterterms. The general results are\nillustrated in the free theory where the Sheikholeslami-Wohlert term is shown\nto affect correlation functions only at O($a^2$), irrespective of its\ncoefficient."
    },
    {
        "anchor": "Parallelizing the QUDA Library for Multi-GPU Calculations in Lattice\n  Quantum Chromodynamics: Graphics Processing Units (GPUs) are having a transformational effect on\nnumerical lattice quantum chromodynamics (LQCD) calculations of importance in\nnuclear and particle physics. The QUDA library provides a package of mixed\nprecision sparse matrix linear solvers for LQCD applications, supporting single\nGPUs based on NVIDIA's Compute Unified Device Architecture (CUDA). This\nlibrary, interfaced to the QDP++/Chroma framework for LQCD calculations, is\ncurrently in production use on the \"9g\" cluster at the Jefferson Laboratory,\nenabling unprecedented price/performance for a range of problems in LQCD.\nNevertheless, memory constraints on current GPU devices limit the problem sizes\nthat can be tackled. In this contribution we describe the parallelization of\nthe QUDA library onto multiple GPUs using MPI, including strategies for the\noverlapping of communication and computation. We report on both weak and strong\nscaling for up to 32 GPUs interconnected by InfiniBand, on which we sustain in\nexcess of 4 Tflops.",
        "positive": "Deconfinement and non-zero baryon density: I discuss a few issues related with deconfinement at finite baryon density by\nconsidering lattice results for two colors QCD and ``toy'' studies of three\ncolors QCD."
    },
    {
        "anchor": "Hadron Structure and Form Factors: We review recent results on hadron form factors and nucleon generalized\nparton distibutions obtained with dynamical lattice QCD simulations. We discuss\nlattice artifacts and open questions, and present the connection of lattice\nresults to hadron structure and to the corresponding quantities measured in\nexperiment.",
        "positive": "Mirror fermions in chiral gauge theories: Mirror fermions appear naturally in lattice formulations of the standard\nmodel. The phenomenological limits on their existence and discovery limits at\nfuture colliders are discussed. After an introduction of lattice actions for\nchiral Yukawa-models, a recent numerical simulation is presented. In\nparticular, the emerging phase structure and features of the allowed region in\nrenormalized couplings are discussed."
    },
    {
        "anchor": "String effects in Polyakov loop correlators: We compare the predictions of the effective string description of confinement\nin finite temperature gauge theories to high precision Monte Carlo data for the\nthree-dimensional Z_2 gauge theory. First we review the predictions of the free\nbosonic string model and their asymptotic behavior in the various regimes of\nphysical interest. Then we show that very good agreement with the Monte Carlo\ndata is obtained, for temperatures not too close to the deconfinement one\n(typically T<T_c/3). For higher temperatures, higher order effects are not\nnegligible: we show that they are accurately modeled by assuming a Nambu-Goto\nstring action and computing its partition function at next-to-leading order.",
        "positive": "Controlling unwanted exponentials in lattice calculations of radiative\n  leptonic decays: Two important sources of systematic errors in lattice QCD calculations of\nradiative leptonic decays are unwanted exponentials in the sum over\nintermediate states and unwanted excited states created by the meson\ninterpolating field. Performing the calculation using a 3d sequential\npropagator allows for better control over the systematic uncertainties from\nintermediate states, while using a 4d sequential propagator allows for better\ncontrol over the systematic uncertainties from excited states. We calculate\nform factors using both methods and compare how reliably each controls these\nsystematic errors. We also employ a hybrid approach involving global fits to\ndata from both methods."
    },
    {
        "anchor": "An improvement in complex Langevin dynamics from a view point of\n  Lefschetz thimbles: We develop a way of improving complex Langevin dynamics motivated by the\nLefschetz-thimble decomposition of integrals. In our method, arbitrary\nobservables of an original model with multiple Lefschetz thimbles are computed\nby a modified model with a single thimble. We apply our modification method to\na one dimensional integral in which the naive implementation of the complex\nLangevin dynamics fails to reproduce the exact results due to the severe sign\nproblem. We show that the toy model can be modified so that the new model\nconsists of a single Lefschetz thimble. We find that correct results can be\nobtained by the improved complex Langevin dynamics.",
        "positive": "A Monte Carlo study of leading order scaling corrections of phi^4 theory\n  on a three dimensional lattice: We present a Monte Carlo study of the one-component $\\phi^4$ model on the\ncubic lattice in three dimensions. Leading order scaling corrections are\nstudied using the finite size scaling method. We compute the corrections to\nscaling exponent $\\omega$ with high precision. We determine the value of the\ncoupling $\\lambda$ at which leading order corrections to scaling vanish. Using\nthis result we obtain estimates for critical exponents that are more precise\nthan those obtained with field theoretic methods."
    },
    {
        "anchor": "SU(3) vortex-like configurations in the maximal center gauge: A new algorithm for fixing the gauge to (direct) maximal center gauge in\nSU(N) lattice gauge theory is presented. We check how this method works on\nSU(3) configurations which are vortex-like, and show how these configurations\nlook like when center projected.",
        "positive": "Nucleon structure from 2+1-flavor dynamical DWF lattice QCD at nearly\n  physical pion mass: Domain-wall fermions (DWF) is a lattice discretization for Dirac fields that\npreserves continuum-like chiral and flavor symmetries that are essential in\nhadron physics. RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations have been\ngenerating sets of realistic 2+1-flavor dynamical lattice quantum\nchromodynamics (QCD) numerical ensembles with DWF quarks with strange mass set\nalmost exactly at its physical value via reweighing and degenerate up and down\nmass set as light as practical. In this report the current status of the\nnucleon-structure calculations using these ensembles are summarized."
    },
    {
        "anchor": "The Crumpling Transition Revisited: The ``crumpling\" transition, between rigid and crumpled surfaces, has been\nobject of much discussion over the past years. The common lore is that such\ntransition should be of second order. However, some lattice versions of the\nrigidity term on fixed connectivity surfaces seem to suggest that the\ntransition is of higher order instead. While some models exhibit what appear to\nbe lattice artifacts, others are really indistiguishable from models where\nsecond order transitions have been reported and yet appear to have third order\ntransitions.",
        "positive": "Heavy-light mesons in lattice HQET and QCD: We present a study of a combination of HQET and relativistic QCD to extract\nthe b-quark mass and the Bs-meson decay constant from lattice quenched\nsimulations. We start from a small volume, where one can directly simulate the\nb-quark, and compute the connection to a large volume, where finite size\neffects are negligible, through a finite size technique. The latter consists of\nsteps extrapolated to the continuum limit, where the b-region is reached\nthrough interpolations guided by the effective theory.\n  With the lattice spacing given in terms of the Sommer's scale r0 and the\nexperimental Bs and K masses, we get the final results for the renormalization\ngroup invariant mass Mb = 6.88(10) GeV, translating into mb(mb) = 4.42(6) GeV\nin the MSbar scheme, and fBs = 191(6) MeV for the decay constant.\n  A renormalization condition for the chromo-magnetic operator, responsible, at\nleading order in the heavy quark mass expansion of HQET, for the mass splitting\nbetween the pseudoscalar and the vector channel in mesonic heavy-light bound\nstates, is provided in terms of lattice correlations functions which well suits\na non-perturbative computation involving a large range of renormalization\nscales and no valence quarks.\n  The two-loop expression of the corresponding anomalous dimension in the\nSchroedinger functional (SF) scheme is computed starting from results in the\nliterature; it requires a one-loop calculation in the SF scheme with a\nnon-vanishing background field. The cutoff effects affecting the scale\nevolution of the renormalization factors are studied at one-loop order, and\nconfirmed by non-perturbative quenched computations to be negligible for the\nnumerical precision achievable at present."
    },
    {
        "anchor": "Renormalizability of the Schr\u00f6dinger Functional: Symanzik showed that quantum field theory can be formulated on a space with\nboundaries by including suitable surface interactions in the action to\nimplement boundary conditions. We show that to all orders in perturbation\ntheory all the divergences induced by these surface interactions can be\nabsorbed by a renormalization of their coefficients.",
        "positive": "Anisotropic lattices for precision computations in heavy flavor physics: We study the anisotropic lattice QCD for precision computations of\nheavy-light matrix elements. Our previous study in which the lattices are\ncalibrated with a few percent accuracy has already given results comparable to\nthe existing calculations. This suggests that even higher precision may be\nachieved by a more precise calibration of anisotropic lattices. We describe our\nstrategy to tune the gauge and quark parameters with accuracies much less than\n1 % in the quenched approximation."
    },
    {
        "anchor": "First evidence for Casimir scaling in G(2) lattice gauge theory: Potentials between static quarks and antiquarks from a few lowest\nrepresentations were evaluated in numerical simulations of 4-dimensional pure\nG$_2$ lattice gauge theory at various couplings. The obtained potentials are\nlinearly rising at intermediate distances and their string tensions exhibit\n(approximate) Casimir scaling. This result is in accordance with a model of the\nvacuum of non-Abelian gauge theories with a domain structure, in which the\n(color) magnetic flux randomly fluctuates within a domain, but the total flux\nin each domain is quantized in units of the gauge group center.",
        "positive": "Lattice study of the infrared behavior of QCD Green's functions in\n  Landau gauge: We summarize the current status of our numerical results for the gluon and\nghost propagators and for the Kugo-Ojima confinement parameter in quenched\nSU(3) lattice Landau gauge theory. The data for the propagators are compared to\nour results obtained in the case of full QCD, simulated using two flavors of\ndynamical clover-improved Wilson fermions. We demonstrate that the infrared\nbehavior of the ghost propagator is consistent with the Kugo-Ojima confinement\ncriterion. Explicit violation of reflection positivity by the gluon propagator\nis shown. Additionally, we present results of a running coupling constant both\nat low and at large momenta."
    },
    {
        "anchor": "Non-perturbative determination of beta-functions and excited string\n  states from lattices: We use lattice sum rules for the static quark potential to determine the\nbeta-function for symmetric and asymmetric lattices non-perturbatively. We also\nstudy the colour field distributions in excited gluonic states.",
        "positive": "On the first-principles determination of the Standard Model fundamental\n  parameters in the quark sector: The 2-years old observation at LHC of a new boson, with a mass of 126 GeV, is\na great achievement. Its interpretation as a Brout-Englert-Higgs boson is very\nplausible and appealing to complete the zoology of fundamental particles in the\nStandard Model. The interplay between theorists and experimentalists that we\nhave witnessed has come with a huge work to determine with enough precision the\nparameters of the Standard Model: couplings, masses, mixing angles. Among the\nvarious tools developed by physicists, lattice QCD is particularly suitable to\nknow those parameters in the quark sector. In this report I discuss the lattice\nmeasurement of Standard Model fundamental parameters that are closely related\nto Higgs boson: its main production mode is the gluon-gluon fusion, whose the\nmagnitude is governed by the strong coupling constant, while its most favored\ndecay channel, $H \\to b \\bar{b}$, has a coupling proportional to the $b$ quark\nmass. I outline the improvements brought by the lattice community: simulations\nwith $N_f=2+1+1$ dynamical quarks are crucial to study how much the charm quark\nimpacts the strong coupling constant calculation. A non perturbative matching\nbetween Heavy Quark Effective Theory and QCD is welcome to handle in an\nappropriate way the $b$ quark physics. An extensive methodological exploration\nis necessary to get rid of contribution from excited states in correlation\nfunctions computed to extract hadron masses and decay constants. The effort to\nmeasure the $u/d$, $s$ and $c$ quark masses is also discussed, illustrating the\nbenefit of using an automatic $O(a)$ improved lattice regularization."
    },
    {
        "anchor": "Direct determination of strange and light quark condensates from full\n  lattice QCD: We determine the strange and light quark condensates in full lattice QCD for\nthe first time. This is done by direct calculation of the expectation value of\nthe trace of the quark propagator followed by subtraction of the appropriate\nperturbative contribution to convert to a value for the condensate in the\nMS-bar scheme at 2 GeV. We use lattice QCD configurations including u, d, s and\nc quarks in the sea with u/d quark masses going down to the physical value. We\nfind the ratio of the strange to the light quark condensate to be 1.08(16).",
        "positive": "Exploration of the electric spin polarizability of the neutron in\n  lattice QCD: A scheme to calculate the electric spin polarizability of the neutron, based\non a four-point function approach to the background field method, is presented.\nThe connected contributions to this spin polarizability are evaluated within a\nmixed action calculation employing domain wall valence quarks on MILC asqtad\nsea quark ensembles. Results are reported for two pion masses, 759 MeV and 357\nMeV."
    },
    {
        "anchor": "Supersymmetric and conformal theories on the lattice: from super\n  Yang-Mills towards super QCD: This talk is an overview of our recent investigations of supersymmetric and\nnear conformal gauge theories. We have studied extensively $\\mathcal{N}=1$\nsuper Yang-Mills theory, most recently with the gauge group SU(3). In addition\nwe have investigated theories that show indications for a conformal behavior at\nan infrared fixed point. We have included a mixed fundamental and adjoint\nfermion action setup in our studies. I will explain how this is related to the\ninvestigation of supersymmetric QCD on the lattice and present some first\nstudies of the main obstacles that need to be addressed in the investigation of\nthis theory.",
        "positive": "Pseudoscalar mesons in a finite cubic volume with twisted boundary\n  conditions: We study the effects of a finite cubic volume with twisted boundary\nconditions on pseudoscalar mesons. We first apply chiral perturbation theory in\nthe p-regime and calculate the corrections for masses, decay constants,\npseudoscalar coupling constants and form factors at next-to-leading order. We\nshow that the Feynman-Hellmann theorem and the relevant Ward-Takahashi identity\nare satisfied. We then derive asymptotic formulae a la Luscher for twisted\nboundary conditions. We show that chiral Ward identities for masses and decay\nconstants are satisfied by the asymptotic formulae in finite volume as a\nconsequence of infinite-volume Ward identities. Applying asymptotic formulae in\ncombination with chiral perturbation theory we estimate corrections beyond\nnext-to-leading order for twisted boundary conditions."
    },
    {
        "anchor": "Lattice Schwinger Model with interpolated Gauge Fields: We analyze the Schwinger model on an infinite lattice using the continuum\ndefinition of the fermion determinant and a linear interpolation of the lattice\ngauge fields. The possible class of interpolations for the gauge fields,\ncompatible with gauge invariance is discussed. The effective action for the\nlattice gauge field is computed for the Wilson formulation as well as for\nnon-compact lattice gauge fields. For the non-compact formulation we prove that\nthe model has a critical point with diverging correlation length at zero gauge\ncoupling e. We compute the chiral condensate for e > 0 and compare the result\nto the N-flavor continuum Schwinger model. This indicates that there is only\none flavor of fermions with the same chiral properties as in the continuum\nmodel, already before the continuum limit is performed. We discuss how\noperators have to be renormalized in the continuum limit to obtain the\ncontinuum Schwinger model.",
        "positive": "Phase diagram of three-dimensional dynamical triangulations with a\n  boundary: We use Monte Carlo simulation to study the phase diagram of three-dimensional\ndynamical triangulations with a boundary. Three phases are indentified and\ncharacterized. One of these phases is a new, boundary dominated phase; a simple\nargument is presented to explain its existence. First-order transitions are\nshown to occur along the critical lines separating phases."
    },
    {
        "anchor": "A calculation of the bulk viscosity in SU(3) gluodynamics: We perform a lattice Monte-Carlo calculation of the trace-anomaly two-point\nfunction at finite temperature in the SU(3) gauge theory. We obtain the\nlong-distance properties of the correlator in the continuum limit and extract\nthe bulk viscosity zeta via a Kubo formula. Unlike the tensor correlator\nrelevant to the shear viscosity, the scalar correlator depends strongly on\ntemperature. If s is the entropy density, we find that zeta/s becomes rapidly\nsmall at high T, zeta/s<0.15 at 1.65T_c and zeta/s<0.015 at 3.2T_c. However\nzeta/s rises dramatically just above T_c, with 0.5<zeta/s<2.0 at 1.02T_c.",
        "positive": "The volume dependence of spectral weights and the pentaquark state: Before studying the pentaquark system we examine the spectral weights of the\ntwo lowest scattering states in the two-pion system in the isospin I=2 channel\non lattices of size $16^3\\times 32$, $24^3 \\times 32$ and $32^3 \\times 64$ at\n$\\beta=6.0$ in the quenched theory. We find that the spectral weights scale\nwith the volume for large time separations. Therefore very accurate data are\nnecessary in order that the spectral weights determined on different volumes\nyield a ratio that is precise enough to distinguish a scattering state from a\nsingle particle state. The pentaquark system is studied on the same lattices\nand scaling of the spectral weights of the low lying state is investigated. The\naccuracy of the results obtained for the scaling of spectral weights do not\nallow us to exclude a pentaquark resonance."
    },
    {
        "anchor": "Chiral perturbation theory for partially quenched twisted mass lattice\n  QCD: Partially quenched Quantum Chromodynamics with Wilson fermions on a lattice\nis considered in the framework of chiral perturbation theory. Two degenerate\nquark flavours are associated with a chirally twisted mass term. The pion\nmasses and decay constants are calculated in next-to-leading order including\nterms linear in the lattice spacing $a$.",
        "positive": "Complex Langevin Dynamics in 1+1d QCD at Non-Zero Densities: We present our results obtained from gauge cooled complex Langevin\nsimulations in 1+1d QCD at non-zero densities in the strong coupling regime\nwith unrooted staggered fermions. For small quark masses there are regions of\nthe chemical potential where this method fails to reproduce correct results. In\nthese parameter ranges we studied the effect of different gauge cooling schemes\non the distributions of the fermion determinant as well as of observables."
    },
    {
        "anchor": "Quark-gluon vertex with an off-shell O(a)-improved chiral fermion action: We perform a study the quark-gluon vertex function with a quenched Wilson\ngauge action and a variety of fermion actions. These include the domain wall\nfermion action (with exponentially accurate chiral symmetry) and the Wilson\nclover action both with the non-perturbatively improved clover coefficient as\nwell as with a number of different values for this coefficient. We find that\nthe domain wall vertex function behaves very well in the large momentum\ntransfer region. The off-shell vertex function for the on-shell improved clover\nclass of actions does not behave as well as the domain wall case and,\nsurprisingly, shows only a weak dependence on the clover coefficient $c_{SW}$\nfor all components of its Dirac decomposition and across all momenta. Including\noff-shell improvement rotations for the clover fields can make this action\nyield results consistent with those from the domain wall approach, as well as\nhelping to determine the off-shell improved coefficient $c_q^\\prime$.",
        "positive": "Bond-weighting method for the Grassmann tensor renormalization group: Recently, the tensor network description with bond weights on its edges has\nbeen proposed as a novel improvement for the tensor renormalization group\nalgorithm. The bond weight is controlled by a single hyperparameter, whose\noptimal value is estimated in the original work via the numerical computation\nof the two-dimensional critical Ising model. We develop this bond-weighted\ntensor renormalization group algorithm to make it applicable to the fermionic\nsystem, benchmarking with the two-dimensional massless Wilson fermion. We show\nthat the accuracy with the fixed bond dimension is improved also in the\nfermionic system and provide numerical evidence that the optimal choice of the\nhyperparameter is not affected by whether the system is bosonic or fermionic.\nIn addition, by monitoring the singular value spectrum, we find that the\nscale-invariant structure of the renormalized Grassmann tensor is successfully\nkept by the bond-weighting technique."
    },
    {
        "anchor": "Mass anomalous dimension of Adjoint QCD at large N from twisted volume\n  reduction: In this work we consider the $SU(N)$ gauge theory with two Dirac fermions in\nthe adjoint representation, in the limit of large $N$. In this limit the\ninfinite-volume physics of this model can be studied by means of the\ncorresponding twisted reduced model defined on a single site lattice. Making\nuse of this strategy we study the reduced model for various values of $N$ up to\n289. By analyzing the eigenvalue distribution of the adjoint Dirac operator we\ntest the conformality of the theory and extract the corresponding mass\nanomalous dimension.",
        "positive": "D meson semileptonic decays in lattice QCD with Moebius domain-wall\n  quarks: We report on our study of the D meson semileptonic decays in 2+1 flavor\nlattice QCD. Gauge ensembles are generated at three lattice cutoffs up to 4.5\nGeV and with pion masses as low as 300 MeV. We employ the Moebius domain-wall\nfermion action for both light and charm quarks. We report our preliminary\nresults for the vector and scalar form factors and discuss their dependence on\nthe momentum transfer, quark masses and lattice spacing."
    },
    {
        "anchor": "QCD on \u03b1-Clusters: It is shown that the 21264 Alpha processor can reach about 20% sustained\nefficiency for the inversion of the Wilson-Dirac operator. Since fast ethernet\nis not sufficient to get balancing between computation and communication on\nreasonable lattice- and system-sizes, an interconnection using Myrinet is\ndiscussed. We find a price/performance ratio comparable with state-of-the-art\nSIMD-systems for lattice QCD.",
        "positive": "Vortex waistlines and long range fluctuations: We examine the manner in which a linear potential results from fluctuations\ndue to vortices linked with the Wilson loop. Our discussion is based on exact\nrelations and inequalities between the Wilson loop and the vortex and electric\nflux order parameters. We show that, contrary to the customary naive picture,\nonly vortex fluctuations of thickness of the order of the spatial linear size\nof the loop are capable of producing a strictly linear potential. An effective\ntheory of these long range fluctuations emerges naturally in the form of a\nstrongly coupled Z(N) lattice gauge theory. We also point out that dynamical\nfermions introduced in this medium undergo chiral symmetry breaking."
    },
    {
        "anchor": "A numerical study of non-perturbative corrections to the Chiral\n  Separation Effect in quenched finite-density QCD: We demonstrate the non-renormalization of the Chiral Separation Effect (CSE)\nin quenched finite-density QCD in both confinement and deconfinement phases\nusing a recently developed numerical method which allows, for the first time,\nto address the transport properties of exactly chiral, dense lattice fermions.\nThis finding suggests that CSE can be used to fix renormalization constants for\naxial current density. Explaining the suppression of the CSE which we observe\nfor topologically nontrivial gauge field configurations on small lattices, we\nalso argue that CSE vanishes for self-dual non-Abelian fields inside instanton\ncores.",
        "positive": "Finite Size Analysis of the U(1) Background Field Effective Action: We apply the finite size scaling analysis to the derivative of the density of\nthe effective action for the lattice U(1) pure gauge theory in an external\nconstant magnetic field. We found the presence of a continuous phase\ntransition. Moreover, our extimate of of the critical parameters gives values\nconsistent with those extracted from the analysis of the specific heat."
    },
    {
        "anchor": "Artefacts and <A2> power corrections : revisiting the MOM Z_psi and Z_V: We extract the power corrections due to the A^2 condensate in the overlap\nquark propagator (vector part of the inverse propagator Z_psi). The results are\nconsistent with the previous gluon analysis. The role of artefacts is\nextensively discussed.",
        "positive": "Phase diagram of QCD with 2+1 flavors of Wilson quarks at finite\n  temperature and chemical potential: The first results on lattice at finite temperature $T$ and chemical potential\n$\\mu$ with 2+1 flavors of Wilson quarks are presented. We have studied the\ndependence of chiral phase transition and deconfinement phase transition on\nquark mass. Finite volume size analysis and Binder cumulants are used to\ndetermine the properties of phase transition. Phase diagram of QCD with 2+1\nflavors of Wilson quarks are presented."
    },
    {
        "anchor": "Spectrum of the Dirac operator in a QCD instanton liquid: two versus\n  three colors: Approximating the sum over all gauge field configurations in the QCD\npartition function by a liquid of instantons, we calculate the spectrum of the\nDirac operator for two and three colors and for 0, 1 and 2 flavors. We find a\nremarkable difference in the spectrum near zero virtuality between 2 and 3\ncolors, which can be explained in terms of chiral random matrix theory. For two\ncolors the Dirac operator is real, and the appropriate random matrix ensemble\nhas real matrix elements. For three colors the Dirac operator is complex, and\nthe spectrum can be described by a random matrix ensemble with complex matrix\nelements. These results provide further evidence that the spectrum near zero\nvirtuality is universal and is completely determined by symmetries.",
        "positive": "The background field method on the lattice: The background field method has been used successfully to determine hadron\nelectromagnetic polarizabilities. Recently questions have been raised regarding\nthe proper way to deal with the electric field on the lattice. In this paper,\nwe show how the presence of a background electric field affects the quark\nhopping matrix. We use this formulation to carry out simulations on quenched\nconfigurations, and we present the results for neutron electric polarizability\nfor pion masses as low as $500\\MeV$. We find that the polarizability is roughly\nconstant for the quark masses considered, $\\alpha\\sim 1.5 \\times 10^{-4}\n\\fm^3$. While the polarizability is positive, it is significantly smaller than\nthe experimental value due to the fact that the quark masses used are too\nlarge."
    },
    {
        "anchor": "Gauge invariant structures and Confinement: By looking at cooled configurations on the lattice, we study the presence of\npeaks in the action density, or its electric and magnetic components, in the\nSU(2) gauge vacuum. The peaks are seen to be of instanton-like nature and their\nnumber variation takes care of the drop in the string tension observed when\ncooling. Possible explanations of this finding are analysed.",
        "positive": "Exploiting stochastic locality in lattice QCD: hadronic observables and\n  their uncertainties: Because of the mass gap, lattice QCD simulations exhibit stochastic locality:\ndistant regions of the lattice fluctuate independently. There is a long history\nof exploiting this to increase statistics by obtaining multiple\nspatially-separated samples from each gauge field; in the extreme case, we\narrive at the master-field approach in which a single gauge field is used. Here\nwe develop techniques for studying hadronic observables using position-space\ncorrelators, which are more localized, and compare with the standard\ntime-momentum representation. We also adapt methods for estimating the variance\nof an observable from autocorrelated Monte Carlo samples to the case of\ncorrelated spatially-separated samples."
    },
    {
        "anchor": "A study of the radiative transition $\u03c0\u03c0\\to \u03c0\u03b3^{*}$ with\n  lattice QCD: Lattice QCD calculations of radiative transitions between hadrons have in the\npast been limited to processes of hadrons stable under the strong interaction.\nRecently developed methods for $1\\to2$ transition matrix elements in a finite\nvolume now enable the determination of radiative decay rates of strongly\nunstable particles. Our lattice QCD study focuses on the process $\\pi \\pi \\to\n\\pi \\gamma^{*}$, where the $\\rho$ meson is present as an enhancement in the\ncross-section. We use $2+1$ flavors of clover fermions at a pion mass of\napproximately $320$ MeV and a lattice size of approximately $3.6$ fm. The\nrequired $2$-point and $3$-point correlation functions are constructed from a\nset of forward, sequential and stochastic light quark propagators. In addition\nto determining the $\\rho$ meson resonance parameters via the L\\\"uscher method,\nthe scattering phase shift is used in conjunction with the $1\\to2$ transition\nmatrix element formalism of Brice\\~no, Hansen and Walker-Loud to compute the\n$\\pi\\pi\\to\\pi\\gamma^{*}$ amplitude at several values of the momentum transfer\nand $\\pi\\pi$ invariant mass.",
        "positive": "Lattice Calculation of Point-to-Point Hadron Current Correlation: Point-to-point correlation functions of hadron currents in the QCD vacuum are\ncalculated on a lattice and analyzed using dispersion relations, providing\nphysical information down to small spatial separations. Qualitative agreement\nwith phenomenological results is obtained in channels for which experimental\ndata are available, and these correlation functions are shown to be useful in\nexploring approximations based on sum rules and interacting instantons."
    },
    {
        "anchor": "Heavy quark action on the anisotropic lattice: We investigate the $O(a)$ improved quark action on anisotropic lattice as a\npotential framework for the heavy quark, which may enable precision computation\nof hadronic matrix elements of heavy-light mesons. The relativity relations of\nheavy-light mesons as well as of heavy quarkonium are examined on a quenched\nlattice with spatial lattice cutoff $a_\\sigma^{-1} \\simeq$ 1.6 GeV and the\nanisotropy $\\xi=4$. We find that the bare anisotropy parameter tuned for the\nmassless quark describes both the heavy-heavy and heavy-light mesons within 2%\naccuracy for the quark mass $a_\\sigma m_Q < 0.8$, which covers the charm quark\nmass. This bare anisotropy parameter also successfully describes the\nheavy-light mesons in the quark mass region $a_\\sigma m_Q \\leq 1.2$ within the\nsame accuracy. Beyond this region, the discretization effects seem to grow\ngradually. The anisotropic lattice is expected to extend by a factor $\\xi$ the\nquark mass region in which the parameters in the action tuned for the massless\nlimit are applicable for heavy-light systems with well controlled systematic\nerrors.",
        "positive": "Implicit schemes for real-time lattice gauge theory: We develop new gauge-covariant implicit numerical schemes for classical\nreal-time lattice gauge theory. A new semi-implicit scheme is used to cure a\nnumerical instability encountered in three-dimensional classical Yang-Mills\nsimulations of heavy-ion collisions by allowing for wave propagation along one\nlattice direction free of numerical dispersion. We show that the scheme is\ngauge covariant and that the Gauss constraint is conserved even for large time\nsteps."
    },
    {
        "anchor": "A lattice formulation of chiral gauge theories: We present a method for implementing gauge theories of chiral fermions on the\nlattice.",
        "positive": "Kaon BSM B-parameters using improved staggered fermions from $N_f=2+1$\n  unquenched QCD: We present results for the matrix elements of the additional $\\Delta S=2$\noperators that appear in models of physics beyond the Standard Model (BSM),\nexpressed in terms of four BSM $B$-parameters. Combined with experimental\nresults for $\\Delta M_K$ and $\\epsilon_K$, these constrain the parameters of\nBSM models. We use improved staggered fermions, with valence HYP-smeared quarks\nand $N_f=2+1$ flavors of \"asqtad\" sea quarks. The configurations have been\ngenerated by the MILC collaboration. The matching between lattice and continuum\nfour-fermion operators and bilinears is done perturbatively at one-loop order.\nWe use three lattice spacings for the continuum extrapolation: $a\\approx 0.09$,\n$0.06$ and $0.045\\;$fm. Valence light-quark masses range down to $\\approx\nm_s^{\\rm phys}/13$ while the light sea-quark masses range down to $\\approx\nm_s^{\\rm phys}/20$. Compared to our previous published work, we have added four\nadditional lattice ensembles, leading to better controlled extrapolations in\nthe lattice spacing and sea-quark masses. We report final results for two\nrenormalization scales, $\\mu=2\\;\\text{GeV}$ and $3\\;\\text{GeV}$, and compare\nthem to those obtained by other collaborations. Agreement is found for two of\nthe four BSM $B$-parameters ($B_2$ and $B_3^\\text{SUSY}$). The other two ($B_4$\nand $B_5$) differ significantly from those obtained using RI-MOM\nrenormalization as an intermediate scheme, but are in agreement with recent\npreliminary results obtained by the RBC-UKQCD collaboration using RI-SMOM\nintermediate schemes."
    },
    {
        "anchor": "Non-perturbative determination of c_V, Z_V and Z_S/Z_P in N_f=3 lattice\n  QCD: We report on non-perturbative computations of the improvement coefficient c_V\nand the renormalization factor Z_V of the vector current in three-flavour O(a)\nimproved lattice QCD with Wilson quarks and tree-level Symanzik improved gauge\naction. To reduce finite quark mass effects, our improvement and normalization\nconditions exploit massive chiral Ward identities formulated in the\nSchroedinger functional setup, which also allow deriving a new method to\nextract the ratio Z_S/Z_P of scalar to pseudoscalar renormalization constants.\nWe present preliminary results of a numerical evaluation of Z_V and c_V along a\nline of constant physics with gauge couplings corresponding to lattice spacings\nof about 0.09 fm and below, relevant for phenomenological applications.",
        "positive": "Nuclear physics from strong coupling QCD: The strong coupling limit (beta_gauge = 0) of QCD offers a number of\nremarkable research possibilities, of course at the price of large lattice\nartifacts. Here, we determine the complete phase diagram as a function of\ntemperature T and baryon chemical potential mu_B, for one flavor of staggered\nfermions in the chiral limit, with emphasis on the determination of a\ntricritical point and on the T ~ 0 transition to nuclear matter. The latter is\nknown to happen for mu_B substantially below the baryon mass, indicating strong\nnuclear interactions in QCD at infinite gauge coupling. This leads us to\nstudying the properties of nuclear matter from first principles. We determine\nthe nucleon-nucleon potential in the strong coupling limit, as well as masses\nm_A of nuclei as a function of their atomic number A. Finally, we clarify the\norigin of nuclear interactions at strong coupling, which turns out to be a\nsteric effect."
    },
    {
        "anchor": "An update in monopole condensation in two-flavour Adjoint QCD: QCD with fermions in the adjoint representation (aQCD) is a model for which a\ndeconfinement and a chiral phase transition take place at different\ntemperatures. In this work, we present a study of the deconfinement transition\nin the dual superconductor picture based on the evaluation of an operator which\ncarries magnetic charge. The expectation value of this operator signals\nmonopole condensation and is an order parameter for deconfinement as in the\ncase of fermions in the fundamental representation. We find a sharp first order\ndeconfinement transition. We also study the effects of the chiral transition on\nthe monopole order parameter and find them negligible.",
        "positive": "Compact lattice QED with Wilson fermions: We study the phase structure and the chiral limit of $4d$ compact lattice QED\nwith Wilson fermions (both dynamical and quenched). We use the standard Wilson\ngauge action and also a modified one suppressing lattice artifacts. Different\ntechniques and observables to locate the chiral limit are discussed."
    },
    {
        "anchor": "Nucleon-Nucleon Scattering From Fully-Dynamical Lattice QCD: We present results of the first fully-dynamical lattice QCD determination of\nnucleon-nucleon scattering lengths in the 1S0 channel and 3S1-3D1 coupled\nchannels. The calculations are performed with domain-wall valence quarks on the\nMILC staggered configurations with lattice spacing of b=0.125 fm in the\nisospin-symmetric limit, and in the absence of electromagnetic interactions.",
        "positive": "$ \u0394$ baryon spectroscopy in lattice QCD: A variational analysis is performed within the framework of lattice QCD to\nextract the masses of the spin-3/2 positive parity $ \\Delta^+ $ baryons,\nincluding radial excitations. $2+1$ flavour dynamical gauge-field\nconfigurations provided by the PACS-CS collaboration via the ILDG are\nconsidered. To improve our interpolator basis, we perform an iterative process\nof source and sink smearing and solve a generalised eigenvalue problem using\nthe resulting fermion operators. We obtain a clear signal for the ground and\nfirst excited states at a light quark mass corresponding to $ m_\\pi = 413 $\nMeV. Furthermore, we show that one can use the eigenvectors obtained in this\nmethod to investigate the nature of these states, allowing us to classify our\nresults as $ 1s $ and $ 2s $ states for the ground and first excited states\nrespectively. Finally, we briefly highlight the method of Hamiltonian Effective\nField Theory which can be used to make comparison with quark model\nexpectations."
    },
    {
        "anchor": "Distances on a Lattice from Non-commutative Geometry: Using the tools of noncommutative geometry we calculate the distances between\nthe points of a lattice on which the usual discretized Dirac operator has been\ndefined. We find that these distances do not have the expected behaviour,\nrevealing that from the metric point of view the lattice does not look at all\nas a set of points sitting on the continuum manifold. We thus have an\nadditional criterion for the choice of the discretization of the Dirac\noperator.",
        "positive": "Chiral Symmetry Breaking in Strongly Coupled 1+1 Dimensional Lattice\n  Gauge Theories: We analyse - within the hamiltonian formalism with staggered fermions - the\npatterns of chiral symmetry breaking for the strongly coupled Schwinger and\n$U({\\cal N}_c)$-color `t Hooft models with one and two flavor of fermions.\nUsing the correspondence between these strongly coupled gauge models and\nantiferromagnetic spin chains, we provide a rather intuitive picture of their\nground states, elucidate their patterns of chiral symmetry breaking, and\ncompute the pertinent chiral condensates. Our analysis evidences an intriguing\nrelationship between the values of the lattice chiral condensates of the `t\nHooft and Schwinger models with one flavor of fermions."
    },
    {
        "anchor": "Taste-split staggered actions: eigenvalues, chiralities and Symanzik\n  improvement: The eigenvalue spectra of staggered fermions with an Adams and/or Hoelbling\nmass term are studied. The chiralities of the eigenmodes reflect whether the\nchirality linked to the unflavored approximate (\\gamma_5 \\times 1) or the\nflavored exact (\\gamma_5 \\times \\xi_5) staggered symmetry is considered, and\nwhich one of the RR, LR, RL, LL eigenmode definitions is used. In either case a\nsensitivity to the topological charge of the gauge background is found. We\ndiscuss how to remove the leading cut-off effects of these actions by means of\na properly tuned improvement term and/or the overlap procedure. The combination\nof Symanzik improvement and link smearing radically improves the properties of\nthe physical branch.",
        "positive": "Four-loop plaquette in 3d with a mass regulator: The QCD free energy can be studied by dimensional reduction to a\nthree-dimensional (3d) effective theory, whereby non-perturbative lattice\nsimulations become less demanding. To connect to the original QCD a\nperturbative matching computation is required, which is conventionally carried\nout in dimensional regularization. Therefore the 3d lattice results need to be\nconverted to this regularization scheme as well. The conversion must be carried\nup to 4-loop order, where the free energy displays an infrared (IR)\nsingularity. We therefore need a regulator which can be implemented both on the\nlattice and in the continuum computation. We introduce a mass regulator to\nperform Numerical Stochastic Perturbation Theory computations. Covariant gauge\nis fixed in the Faddeev-Popov scheme without introducing any ghost fields."
    },
    {
        "anchor": "Softening Transitions with Quenched 2D Gravity: We perform extensive Monte Carlo simulations of the 10-state Potts model on\nquenched two-dimensional $\\Phi^3$ gravity graphs to study the effect of\nquenched connectivity disorder on the phase transition, which is strongly first\norder on regular lattices. The numerical data provides strong evidence that,\ndue to the quenched randomness, the discontinuous first-order phase transition\nof the pure model is softened to a continuous transition.",
        "positive": "Two-Nucleon Systems in a Finite Volume: (II) 3S1-3D1 Coupled Channels\n  and the Deuteron: The energy spectra of two nucleons in a cubic volume provide access to the\ntwo phase shifts and one mixing angle that define the S-matrix in the 3S1-3D1\ncoupled channels containing the deuteron. With the aid of recently derived\nenergy quantization conditions for such systems, and the known scattering\nparameters, these spectra are predicted for a range of volumes. It is found\nthat extractions of the infinite-volume deuteron binding energy and leading\nscattering parameters, including the S-D mixing angle at the deuteron pole, are\npossible from Lattice QCD calculations of two-nucleon systems with boosts of\n|P| <= 2pi sqrt{3}/L in volumes with 10 fm <~ L <~ 14 fm. The viability of\nextracting the asymptotic D/S ratio of the deuteron wavefunction from Lattice\nQCD calculations is discussed."
    },
    {
        "anchor": "Pi-Pi Scattering with Nf=2+1+1 Twisted Mass Fermions: Pi-Pi scattering is investigated for the first time for Nf=2+1+1 dynamical\nquark flavours using Wilson twisted mass fermions. L\\\"uscher's finite size\nmethod is used to relate energy shifts in finite volume to scattering\nquantities like the scattering length in the I=2 channel. The computation is\nperformed at several pion masses and lattice spacings utilising the stochastic\nLapH method.",
        "positive": "Localization and topology in high temperature QCD: At high temperature part of the spectrum of the quark Dirac operator is known\nto consist of localized states. This comes about because around the crossover\ntemperature to the quark-gluon plasma localized states start to appear at the\nlow end of the spectrum and as the system is further heated, states higher up\nin the spectrum also get localized. Since localization and the crossover to the\nchirally restored phase happen around the same temperature, the question of how\nthe two phenomena are connected naturally arises. Here we speculate on the\nnature of possible gauge configurations that could support localized quark\neigenmodes. In particular, by analyzing eigenmodes of the staggerd and overlap\nDirac operator we show that the dilute gas of calorons in the high temperature\nphase is very unlikely to play a major role in localization."
    },
    {
        "anchor": "Proton Mass Decomposition from the QCD Energy Momentum Tensor: We report results on the proton mass decomposition and also on related quark\nand glue momentum fractions. The results are based on overlap valence fermions\non four ensembles of $N_f = 2+1$ DWF configurations with three lattice spacings\nand three volumes, and several pion masses including the physical pion mass.\nWith fully non-perturbative renormalization (and universal normalization on\nboth quark and gluon), we find that the quark energy and glue field energy\ncontribute 33(4)(4)\\% and 37(5)(4)\\% respectively in the $\\overline{MS}$ scheme\nat $\\mu = 2$ GeV. A quarter of the trace anomaly gives a 23(1)(1)\\%\ncontribution to the proton mass based on the sum rule, given 9(2)(1)\\%\ncontribution from the $u, d,$ and $s$ quark scalar condensates. The $u,d,s$ and\nglue momentum fractions in the $\\overline{MS}$ scheme are in good agreement\nwith global analyses at $\\mu = 2$ GeV.",
        "positive": "A lattice study of a chirally invariant Higgs-Yukawa model including a\n  higher dimensional $\u03a6^6$-term: We discuss the non-thermal phase structure of a chirally invariant\nHiggs-Yukawa model on the lattice in the presence of a higher dimensional\n$\\Phi^6$-term. For the exploration of the phase diagram we use analytical,\nlattice perturbative calculations of the constraint effectice potential as well\nas numerical simulations. We also present first results of the effects of the\n$\\Phi^6$-term on the lower Higgs boson mass bounds."
    },
    {
        "anchor": "Applying Complex Langevin Simulations to Lattice QCD at Finite Density: We study the use of the complex-Langevin equation (CLE) to simulate lattice\nQCD at a finite chemical potential ($\\mu$) for quark-number, which has a\ncomplex fermion determinant that prevents the use of standard simulation\nmethods based on importance sampling. Recent enhancements to the CLE specific\nto lattice QCD inhibit runaway solutions which had foiled earlier attempts to\nuse it for such simulations. However, it is not guaranteed to produce correct\nresults. Our goal is to determine under what conditions the CLE yields correct\nvalues for the observables of interest. Zero temperature simulations indicate\nthat for moderate couplings, good agreement with expected results is obtained\nfor small $\\mu$ and for $\\mu$ large enough to reach saturation, and that this\nagreement improves as we go to weaker coupling. For intermediate $\\mu$ values\nthese simulations do not produce the correct physics. We compare our results\nwith those of the phase-quenched approximation. Since there are indications\nthat correct results might be obtained if the CLE trajectories remain close to\nthe $SU(3)$ manifold, we study how the distance from this manifold depends on\nthe quark mass and on the coupling. We find that this distance decreases with\ndecreasing quark mass and as the coupling decreases, i.e. as the simulations\napproach the continuum limit.",
        "positive": "QCD equation of state via the complex Langevin method: We present lattice simulations on the phase diagram of Quantum Chromodynamics\n(QCD) with two light quark flavours at finite chemical potential $\\mu$. To\ncircumvent the sign problem we use the complex Langevin method. In this study,\nwe have carried out finite density lattice computations for a pion mass of\n$\\sim 480$ MeV. We report on the pressure, energy and entropy equations of\nstate in ab-initio lattice QCD calculations, as well as the observation of the\nSilver Blaze phenomenon."
    },
    {
        "anchor": "QCD thermodynamics with dynamical overlap fermions: We study QCD thermodynamics using two flavors of dynamical overlap fermions\nwith quark masses corresponding to a pion mass of 350 MeV. We determine several\nobservables on N_t=6 and 8 lattices. All our runs are performed with fixed\nglobal topology. Our results are compared with staggered ones and a nice\nagreement is found.",
        "positive": "Equation of state of the SU($3$) Yang-Mills theory: a precise\n  determination from a moving frame: The equation of state of the SU($3$) Yang-Mills theory is determined in the\ndeconfined phase with a precision of about 0.5%. The calculation is carried out\nby numerical simulations of lattice gauge theory with shifted boundary\nconditions in the time direction. At each given temperature, up to $230\\, T_c$\nwith $T_c$ being the critical temperature, the entropy density is computed at\nseveral lattice spacings so to be able to extrapolate the results to the\ncontinuum limit with confidence. Taken at face value, above a few $T_c$ the\nresults exhibit a striking linear behaviour in $\\ln(T/T_c)^{-1}$ over almost 2\norders of magnitude. Within errors, data point straight to the Stefan-Boltzmann\nvalue but with a slope grossly different from the leading-order perturbative\nprediction. The pressure is determined by integrating the entropy in the\ntemperature, while the energy density is extracted from $T s=(\\epsilon + p )$.\nThe continuum values of the potentials are well represented by Pad\\'e\ninterpolating formulas, which also connect them well to the Stefan-Boltzmann\nvalues in the infinite temperature limit. The pressure, the energy and the\nentropy densities are compared with results in the literature. The discrepancy\namong previous computations near $T_c$ is analyzed and resolved thanks to the\nhigh precision achieved."
    },
    {
        "anchor": "Path optimization for $U(1)$ gauge theory with complexified parameters: In this article, we apply the path optimization method to handle the\ncomplexified parameters in the 1+1 dimensional pure $U(1)$ gauge theory on the\nlattice. Complexified parameters make it possible to explore the Lee-Yang zeros\nwhich helps us to understand the phase structure and thus we consider the\ncomplex coupling constant with the path optimization method in the theory. We\nclarify the gauge fixing issue in the path optimization method; the gauge\nfixing helps to optimize the integration path effectively. With the gauge\nfixing, the path optimization method can treat the complex parameter and\ncontrol the sign problem. It is the first step to directly tackle the Lee-Yang\nzero analysis of the gauge theory by using the path optimization method.",
        "positive": "Extrapolation Formulas for Neutron EDM Calculations in Lattice QCD: Lattice QCD is rapidly progressing toward being able to reliably compute the\nelectric dipole moment of the neutron as a function of the strong CP-violating\nparameter theta. Present day calculations are performed at unphysical values of\nthe light quark masses, in volumes that are not exceptionally large and at\nlattice spacings that are not exceptionally small. We use chiral perturbation\ntheory to determine the leading contributions to the neutron electric dipole\nmoment at finite volume, and in partially-quenched calculations."
    },
    {
        "anchor": "The mass of the Delta resonance in a finite volume: fourth-order\n  calculation: We calculate the self-energy of the Delta (1232) resonance in a finite\nvolume, using chiral effective field theory with explicit spin-3/2 fields. The\ncalculations are performed up-to-and-including fourth order in the small scale\nexpansion and yield an explicit parameterization of the energy spectrum of the\ninteracting pion-nucleon pair in a finite box in terms of both the quark mass\nand the box size L. It is shown that finite-volume corrections can be sizeable\nat small quark masses.",
        "positive": "Exploring a new approach to Hadronic Parity Violation from Lattice QCD: The long-range, parity-odd nucleon interaction generated by single pion\nexchange is captured in the parity-odd pion-nucleon coupling $h^1_\\pi$. Its\ncalculation in lattice QCD requires the evaluation of 4-quark operator nucleon\n3-point functions. We investigate a new numerical approach to compute $h^1_\\pi$\nbased on nucleon matrix elements of parity-even 4-quark operators and related\nto the parity-violating electro-weak theory by PCAC and chiral perturbation\ntheory. This study is performed with 2+1+1 dynamical flavors of twisted mass\nfermions at pion mass $m_{\\pi} \\approx 260\\,\\text{MeV}$ in a lattice box of $L\n\\approx 3 \\,\\text{fm} $ and with a lattice spacing of $a \\approx 0.091\n\\,\\text{fm}$. From a calculation excluding fermion loop diagrams we find a bare\ncoupling of $h^1_\\pi = 8.08 \\,(98) \\cdot 10^{-7}$."
    },
    {
        "anchor": "Approaching the chiral point in two-flavour lattice simulations: We investigate the behaviour of the pion decay constant and the pion mass in\ntwo-flavour lattice QCD, with the physical and chiral points as ultimate goal.\nMeasurements come from the ensembles generated by the CLS initiative using the\nO(a)-improved Wilson formulation, with lattice spacing down to about 0.05 fermi\nand pion masses as low as 190 MeV. The applicability of SU(2) chiral\nperturbation theory is investigated, and various functional forms, and their\nrange of validity, are compared. The physical scale is set through the kaon\ndecay constant, whose measurement is enabled by inserting a third, heavier\nvalence strange quark.",
        "positive": "B-parameters for $\u0394S = 2$ SUSY Operators: We present the first lattice measurement, using Non Perturbative\nRenormalization Method, of the B-parameters of the dimension-six four-fermion\noperators relevant for the supersymmetric corrections to the $\\Delta S=2$\ntransitions."
    },
    {
        "anchor": "Pion Distribution Amplitude from Lattice QCD: We present the first lattice-QCD calculation of the pion distribution\namplitude using the large- momentum effective field theory (LaMET) approach,\nwhich allows us to extract lightcone parton observables from a Euclidean\nlattice. The mass corrections needed to extract the pion distribution amplitude\nfrom this approach are calculated to all orders in $m^2_{\\pi} /P_z^2$. We also\nimplement the Wilson- line renormalization which is crucial to remove the power\ndivergences in this approach, and find that it reduces the oscillation at the\nend points of the distribution amplitude. Our exploratory result at 310-MeV\npion mass favors a single-hump form broader than the asymptotic form of the\npion distribution amplitude.",
        "positive": "Weak Matrix Elements on the Lattice --- Circa 1995: Status of weak matrix elements is reviewed. In particular, $\\epspeps$,\n$\\bkastg$, $B_K$, $B_B$ and $B_{B_s}$ are discussed and the overall situation\nwith respect to the lattice effort and some of its phenomenological\nimplications are summarized. For $\\epspeps$ the need for the relevant matrix\nelements is stressed in view of the forthcoming improved experiments. For some\nof the operators, (e.g.\\ $O_6$), even bounds on their matrix elements would be\nvery helpful. On $\\bkastg$, a constant behavior of $T_2$ appears disfavored\nalthough dependence of $T_2$ could, of course, be milder than a simple pole.\nImproved data is badly needed to settle this important issue firmly, especially\nin view of its ramification for extractions of $V_{td}$ from $B\\to\\rho\\gamma$.\nOn $B_K$, the preliminary result from JLQCD appears to contradict Sharpe \\etal\\\nJLQCD data seems to fit very well to linear $a$ dependence and leads to an\nappreciably lower value of $B_K$. Four studies of $B_K$ in the ``full''\n($n_f=2$) theory indicate very little quenching effects on $B_K$; the full\ntheory value seems to be just a little less than the quenched result. Based on\nexpectations from HQET, analysis of the $B$-parameter ($B_{h\\ell}$) for the\nheavy-light mesons via\n$B_{h\\ell}={}$constant${}+{}$constants$^\\prime/m_{h\\ell}$ is suggested. A\nsummary of an illustrative sample of hadron matrix elements is given and\nconstraints on CKM parameters (e.g.\\ $V_{td}/V_{ts}$), on the unitarity\ntriangle and on $x_s/x_d$, emerging from the lattice calculations along with\nexperimental results are briefly discussed. In quite a few cases, for the first\ntime, some indication of quenching errors on weak matrix elements are now\nbecoming available."
    },
    {
        "anchor": "Exploratory study of three-point Green's functions in Landau-gauge\n  Yang-Mills theory: Green's functions are a central element in the attempt to understand\nnon-perturbative phenomena in Yang-Mills theory. Besides the propagators,\n3-point Green's functions play a significant role, since they permit access to\nthe running coupling constant and are an important input in functional methods.\nHere we present numerical results for the two non-vanishing 3-point Green's\nfunctions in 3d pure SU(2) Yang-Mills theory in (minimal) Landau gauge, i.e.\nthe three-gluon vertex and the ghost-gluon vertex, considering various\nkinematical regimes. In this exploratory investigation the lattice volumes are\nlimited to 20^3 and 30^3 at beta=4.2 and beta=6.0. We also present results for\nthe gluon and the ghost propagators, as well as for the eigenvalue spectrum of\nthe Faddeev-Popov operator. Finally, we compare two different numerical methods\nfor the evaluation of the inverse of the Faddeev-Popov matrix, the point-source\nand the plane-wave-source methods.",
        "positive": "QCD plasma instability and thermalisation at heavy ion collisions: Under suitable non-equilibrium conditions QCD plasma can develop plasma\ninstabilities, where some modes of the plasma grow exponentially. It has been\nargued that these instabilities can play a significant role in the\nthermalisation of the plasma in heavy-ion collision experiments. We study the\ninstability in SU(2) plasmas using the hard thermal loop effective lattice\ntheory, which is suitable for studying real-time evolution of long wavelength\nmodes in the plasma. We observe that under suitable conditions the plasma can\nindeed develop an instability which can grow to a very large magnitude,\nnecessary for the rapid thermalisation in heavy-ion collisions."
    },
    {
        "anchor": "Improvement of efficiency in generating random $U(1)$ variables with\n  Boltzmann distribution: A method for generating random $U(1)$ variables with Boltzmann distribution\nis presented. It is based on the rejection method with transformation of\nvariables. High efficiency is achieved for all range of temparatures or\ncoupling parameters, which makes the present method especially suitable for\nparallel and pipeline vector processing machines. Results of computer runs are\npresented to illustrate the efficiency. An idea to find such algorithms is also\npresented, which may be applicable to other distributions of interest in Monte\nCarlo simulations.",
        "positive": "Lattice QCD input for nuclear structure and reactions: Explorations of the properties of light nuclear systems beyond their\nlowest-lying spectra have begun with Lattice Quantum Chromodynamics. While\nprogress has been made in the past year in pursuing calculations with physical\nquark masses, studies of the simplest nuclear matrix elements and nuclear\nreactions at heavier quark masses have been conducted, and several interesting\nresults have been obtained. A community effort has been devoted to investigate\nthe impact of such Quantum Chromodynamics input on the nuclear many-body\ncalculations. Systems involving hyperons and their interactions have been the\nfocus of intense investigations in the field, with new results and deeper\ninsights emerging. While the validity of some of the previous multi-nucleon\nstudies has been questioned during the past year, controversy remains as\nwhether such concerns are relevant to a given result. In an effort to summarize\nthe newest developments in the field, this talk will touch on most of these\ntopics."
    },
    {
        "anchor": "Relating U(1) monopole configurations to SU(2) saddle-point\n  configurations: We have studied field configurations of the 3-dimensional Georgi-Glashow\nmodel which interpolate between the $U(1)$ and the $SU(2)$ limits. In the\nintermediate region, these configurations contain 't-Hooft--Polyakov monopoles.\nWe use cooling and extremization to find these configurations and investigate\ntheir evolution as we adiabatically move towards the $U(1)$ and the $SU(2)$\nlimits. We also evolve an $SU(2)$ saddle point solution towards the $U(1)$\nlimit to see the relation between the unstable solutions in the $SU(2)$ theory\nand the stable ones in the $U(1)$ theory.",
        "positive": "Kaon $B$-parameter from improved staggered fermions in $N_f=2+1$ QCD: We present a calculation of the kaon $B$-parameter, $B_K$, using lattice QCD.\nWe use improved staggered valence and sea fermions, the latter generated by the\nMILC collaboration with $N_f=2+1$ light flavors. To control discretization\nerrors, we use four different lattice spacings ranging down to $a\\approx\n0.045\\;$fm. The chiral and continuum extrapolations are done using SU(2)\nstaggered chiral perturbation theory. Our final result is $\\hat{B}_K = 0.727\n\\pm 0.004 (\\text{stat}) \\pm 0.038 (\\text{sys})$, where the dominant systematic\nerror is from our use of truncated (one-loop) matching factors."
    },
    {
        "anchor": "Large-q expansion of the correlation length in the two-dimensional\n  q-state Potts model: The large-q expansions of the exponential correlation length and the second\nmoment correlation length for the q-state Potts model in two dimensions are\ncalculated at the first order phase transition point both in the ordered and\ndisordered phases. The expansion coefficients in the ordered and disordered\nphases coincide in lower orders for both of the two types of the correlation\nlengths, but they differ a little from each other in higher orders for the\nsecond moment correlation length. The second largest eigenvalues of the\ntransfer matrix have the continuum spectrum both in the ordered and disordered\nphases in the large-q region, which is suggested to be maintained even in the\nlimit of $q\\to 4$ from the analysis of the expansion series.",
        "positive": "Automated lattice perturbation theory and relativistic heavy quarks in\n  the Columbia formulation: We introduce a new computer algebra system optimized for use in lattice\nperturbation theory as well as continuum perturbation theory and a new\nframework to perform automated perturbative calculations on top of said\ncomputer algebra system. The new framework is used to tune the relativistic\nheavy quark action in the Columbia formulation at one loop in\nmeanfield-improved perturbation theory. Preliminary results for the matching\nand O(a)-improvement of heavy-light axial vector currents with light\ndomain-wall quarks are also presented."
    },
    {
        "anchor": "Understanding Color Confinement: An updated review is presented of our understanding of color confinement.\nLattice results on condensation of magnetic charges are discussed. The role of\nvortices is analysed.",
        "positive": "Phenomenology using lattice QCD: This talk provides a brief summary of the status of lattice QCD calculations\nof the light quark masses and the kaon bag parameter B_K. Precise estimates of\nthese four fundamental parameters of the standard model, i.e., m_u, m_d, m_s\nand the CP violating parameter eta, help constrain grand unified models and\ncould provide a window to new physics."
    },
    {
        "anchor": "D semi-leptonic decay form factors with HISQ charm and light quarks: We present a program to study D semi-leptonic decay form factors with HISQ\ncharm and light quarks. In this exploratory work, we study $D_s$ to $\\eta_s$,\n$l\\nu_l$ semi-leptonic decay on MILC coarse ($20^3\\times64$) gauge\nconfigurations with 2+1 dynamical flavors. We develop a new method to calculate\n$f_+(0)$ and $f_0(q^2)$ from scalar current matrix elements,\n$<\\pi|\\bar{s}c|D>$, which does not require any operator renormalization. We\nalso determine $f_+(q^2)$ and $f_0(q^2)$ from vector currents with a fully\nnon-perturbative renormalization method.",
        "positive": "A hidden classical symmetry of QCD: The classical part of the QCD partition function (the integrand) has,\nignoring irrelevant exact zero modes of the Dirac operator, a local SU(2N_F)\n\\supset SU(N_F)_L \\times SU(N_F)_R \\times U(1)_A symmetry which is absent at\nthe Lagrangian level. This symmetry is broken anomalously and spontaneously.\nEffects of spontaneous breaking of chiral symmetry are contained in the\nnear-zero modes of the Dirac operator. If physics of anomaly is also encoded in\nthe same near-zero modes, then their truncation on the lattice should recover a\nhidden classical SU(2N_F) symmetry in correlators and spectra. This naturally\nexplains observation on the lattice of a large degeneracy of hadrons, that is\nhigher than the SU(N_F)_L \\times SU(N_F)_R \\times U(1)_A chiral symmetry, upon\nelimination by hands of the lowest-lying modes of the Dirac operator. We also\ndiscuss an implication of this symmetry for the high temperature QCD."
    },
    {
        "anchor": "Constrained Curve Fitting: We survey techniques for constrained curve fitting, based upon Bayesian\nstatistics, that offer significant advantages over conventional techniques used\nby lattice field theorists.",
        "positive": "Partially twisted boundary conditions for scalar mesons: The possibility of imposing partially twisted boundary conditions in the\nlattice study of the resonance states is investigated by using the effective\nfield theory (EFT) methods. In particular, it is demonstrated that - in certain\ncases - it is possible to use partial twisting even in the presence of the\nquark annihilation diagrams."
    },
    {
        "anchor": "Broken Valence Chiral Symmetry and Chiral Polarization of Dirac Spectrum\n  in N$_f$=12 QCD at Small Quark Mass: The validity of recently proposed equivalence between valence spontaneous\nchiral symmetry breaking (vSChSB) and chiral polarization of low energy Dirac\nspectrum (ChP) in SU(3) gauge theory, is examined for the case of twelve\nmass-degenerate fundamental quark flavors. We find that the vSChSB-ChP\ncorrespondence holds for regularized systems studied. Moreover, our results\nsuggest that vSChSB occurs in two qualitatively different circumstances: there\nis a quark mass $m_c$ such that for $m > m_c$ the mode condensing Dirac\nspectrum exhibits standard monotonically increasing density, while for $m_{ch}\n< m < m_c$ the peak around zero separates from the bulk of the spectrum, with\ndensity showing a pronounced depletion at intermediate scales. Valence chiral\nsymmetry restoration may occur at yet smaller masses $m < m_{ch}$, but this has\nnot yet been seen by overlap valence probe, leaving the $m_{ch}=0$ possibility\nopen. The latter option could place massless N$_f$=12 theory outside of\nconformal window. Anomalous behavior of overlap Dirac spectrum for $m_{ch} < m\n< m_c$ is qualitatively similar to one observed previously in zero and\nfew-flavor theories as an effect of thermal agitation.",
        "positive": "Infrared-suppressed gluon propagator in 4d Yang-Mills theory in a\n  Landau-like gauge: The infrared behavior of the gluon propagator is directly related to\nconfinement in QCD. Indeed, the Gribov-Zwanziger scenario of confinement\npredicts an infrared vanishing (transverse) gluon propagator in Landau-like\ngauges, implying violation of reflection positivity and gluon confinement.\nFinite-volume effects make it very difficult to observe (in the minimal Landau\ngauge) an infrared suppressed gluon propagator in lattice simulations of the\nfour-dimensional case. Here we report results for the SU(2) gluon propagator in\na gauge that interpolates between the minimal Landau gauge (for gauge parameter\nlambda equal to 1) and the minimal Coulomb gauge (corresponding to lambda = 0).\nFor small values of lambda we find that the spatially-transverse gluon\npropagator D^tr(0,|\\vec p|), considered as a function of the spatial momenta\n|\\vec p|, is clearly infrared suppressed. This result is in agreement with the\nGribov-Zwanziger scenario and with previous numerical results in the minimal\nCoulomb gauge. We also discuss the nature of the limit lambda -> 0 (complete\nCoulomb gauge) and its relation to the standard Coulomb gauge (lambda = 0). Our\nfindings are corroborated by similar results in the three-dimensional case,\nwhere the infrared suppression is observed for all considered values of lambda."
    },
    {
        "anchor": "The Interface Tension in Quenched QCD at the Critical Temperature: We present results for the confinement-deconfinement interface tension\n$\\alpha_{cd}$ of quenched QCD. They were obtained by applying Binder's\nhistogram method to lattices of size $L^2\\times L_z\\times L_t$ for $L_t=2$ and\n$L=8,10,12\\mbox{ and }14$ with $L_z=30$ for $L=8$ and $L_z=3L$ otherwise. The\nuse of a multicanonical algorithm and cylindrical geometries have turned out to\nbe crucial for the numerical studies.",
        "positive": "Chiral Extrapolation of the Sigma Resonance: We analyze recent results on isoscalar $\\pi\\pi$ scattering from a $N_f=2+1$\nlattice simulation by the HadronSpectrum collaboration by re-summing the\ntwo-flavor chiral scattering amplitude of the next-to-leading order in the\nso-called inverse amplitude method. The lattice data can be well extrapolated\nto the physical pion mass. We also find that both $I=0$ and $I=1$ lattice data\ncan be described simultaneously for pion masses up to $M_{\\pi}=236$ MeV."
    },
    {
        "anchor": "B-parameters of 4-fermion operators from lattice QCD: This talk summarizes the status of the calculations of $B_K$, $B_7$, $B_8$,\nand $B_s$, done in collaboration with T. Bhattacharya, G. Kilcup, and S.\nSharpe. Results for staggered, Wilson, and Clover fermions are presented.",
        "positive": "Electromagnetic corrections to light hadron masses: At the precision reached in current lattice QCD calculations, electromagnetic\neffects are becoming numerically relevant. We will present preliminary results\nfor electromagnetic corrections to light hadron masses, based on simulations in\nwhich a $\\mathrm{U}(1)$ degree of freedom is superimposed on $N_f=2+1$ QCD\nconfigurations from the BMW collaboration."
    },
    {
        "anchor": "Universal Scaling of the Chiral Condensate in Finite-Volume Gauge\n  Theories: We confront exact analytical predictions for the finite-volume scaling of the\nchiral condensate with data from quenched lattice gauge theory simulations.\nUsing staggered fermions in both the fundamental and adjoint representations,\nand gauge groups SU(2) and SU(3), we are able to test simultaneously all of the\nthree chiral universality classes. With overlap fermions we also test the\npredictions for gauge field sectors of non-zero topological charge. Excellent\nagreement is found in most cases, and the deviations are understood in the\nothers.",
        "positive": "Scaling and asymptotic scaling in two-dimensional $CP^{N-1}$ models: Two-dimensional $CP^{N-1}$ models are investigated by Monte Carlo methods on\nthe lattice, for values of $N$ ranging from 2 to 21. Scaling and rotation\ninvariance are studied by comparing different definitions of correlation length\n$\\xi$. Several lattice formulations are compared and shown to enjoy scaling for\n$\\xi$ as small as $2.5$. Asymptotic scaling is investigated using as bare\ncoupling constant both the usual $\\beta$ and $\\beta_E$ (related to the internal\nenergy); the latter is shown to improve asymptotic scaling properties. Studies\nof finite size effects show their $N$-dependence to be highly non-trivial, due\nto the increasing radius of the $\\bar z z$ bound states at large $N$."
    },
    {
        "anchor": "Random Walk Representation of the Lattice Fermionic Propagators and the\n  Quark Model: A representation of the continuum fermionic propagator as a sum of directed\nrandom walks on a lattice is presented. Also a random walk representation for\nthe lattice fermionic propagators is developed for the case of the naive, the\nWilson, and the Kogut-Susskind fermions. For the naive fermions the phenomenon\nof fermion doubling appears as having $2^{D}$ distinct spin factors being\nassociated with a single path in $D$-dimensions. In the case of the Wilson and\nthe Kogut-Susskind fermions, in the naive continuum limit, the path integral\nrepresentation coincides with the path integral representation for the\ncontinuum fermionic propagator. Using this representation the Green's functions\nof lattice QCD involving quark operators are written as a sum over the paths of\nvalence quark, the gauge fields and the sea quarks being integrated out.\nPossible advantages of such a representation are illustrated by showing how one\ncan use numerical simulations to obtain a heuristic insight into the\nrelationship between QCD and the constituent quark model.",
        "positive": "Cluster Percolation and Pseudocritical Behaviour in Spin Models: The critical behaviour of many spin models can be equivalently formulated as\npercolation of specific site-bond clusters. In the presence of an external\nmagnetic field, such clusters remain well-defined and lead to a percolation\ntransition, even though the system no longer shows thermal critical behaviour.\nWe investigate the 2-dimensional Ising model and the 3-dimensional O(2) model\nby means of Monte Carlo simulations. We find for small fields that the line of\npercolation critical points has the same functional form as the line of thermal\npseudocritical points."
    },
    {
        "anchor": "Excited states in nucleon structure calculations: Excited state contributions represent a formidable challenge for hadron\nstructure calculations in lattice QCD. For physical systems that exhibit an\nexponential signal-to-noise problem they often hinder the extraction of ground\nstate matrix elements, introducing a major source of systematic error in\nlattice calculations of such quantities. The development of methods to treat\nthe contribution of excited states and the current status of related lattice\nstudies are reviewed with focus on nucleon structure calculations that are\nnotoriously affected by excited state contamination.",
        "positive": "Tensor network study of two dimensional lattice $\u03c6^{4}$ theory: The tensor renormalization group attracts great attention as a new numerical\nmethod that is free of the sign problem. In addition to this striking feature,\nit also has an attractive aspect as a coarse-graining of space-time; the\ncomputational cost scales logarithmically with the space-time volume. This fact\nallows us to aggressively approach the thermodynamic limit. While taking this\nadvantage, we study the critical coupling of the two dimensional $\\phi^{4}$\ntheory on large and fine lattices. We present the numerical results along with\nthe extrapolation procedure to the continuum limit and compare them with the\nprevious ones by Monte Carlo simulations."
    },
    {
        "anchor": "Inclusive semi-leptonic decays of charmed mesons with M\u00f6bius domain\n  wall fermions: We perform a non-perturbative lattice calculation of the decay rates for\ninclusive semi-leptonic decays of charmed mesons. In view of the long-standing\ntension in the determination of the CKM matrix elements $|V_{ub}|$ and\n$|V_{cb}|$ from exclusive and inclusive processes, recently, the use of lattice\nQCD has been extended towards the description of inclusive decays. Since the\ndetermination of hadronic input parameters from QCD based methods require\nindependent tests, we focus on the charm sector, since it not only offers\nexperimental data, but also well determined CKM parameters. We carry out a\npilot lattice simulation for the $D_s \\rightarrow X_s \\ell\\nu$ and explore the\nimprovement of existing techniques. Our simulation employs M\\\"obius domain-wall\ncharm and strange quarks whose masses are tuned to be approximately physical\nand we cover the whole kinematical region. We report on our progress in\nanalyzing different sources of systematic effects, such as the extrapolation of\nthe kernel function chosen for the Chebsyhev approximation as well as the\ninfluence on the analysis in the region close to the kinematical limit.",
        "positive": "Static-light mesons on a dynamical anisotropic lattice: We present results for the spectrum of static-light mesons from Nf=2 lattice\nQCD. These results were obtained using all-to-all light quark propagators on an\nanisotropic lattice, yielding an improved signal resolution when compared to\nmore conventional lattice techniques. In particular, we consider the inversion\nof orbitally-excited multiplets with respect to the `standard ordering', which\nhas been predicted by some quark models."
    },
    {
        "anchor": "Six-dimensional regularization of chiral gauge theories on a lattice: We propose a six-dimensional regularization of four dimensional chiral gauge\ntheories. We consider a massive Dirac fermion in six dimensions with two\ndifferent operators having domain-wall profiles in the fifth and the sixth\ndirections, respectively. A Weyl fermion appears as a localized mode at the\njunction of the two domain-walls. In our formulation, the Stora-Zumino chain of\nthe anomaly descent equations, starting from the axial $U(1)$ anomaly in\nsix-dimensions to the gauge anomaly in four-dimensions, is naturally embedded.\nMoreover, a similar inflow of the global anomalies is found. The anomaly free\ncondition is equivalent to requiring that the axial $U(1)$ anomaly and the\nparity anomaly are canceled among the six-dimensional Dirac fermions. Putting\nthe gauge field at the four- dimensional junction and extending it to the bulk\nusing the Yang-Mills gradient flow, as recently proposed by Grabowska and\nKaplan, we define the four-dimensional path integral of the target chiral gauge\ntheory.",
        "positive": "Scaling tests with dynamical overlap and rooted staggered fermions: We present a scaling analysis in the 1-flavor Schwinger model with the full\noverlap and the rooted staggered determinant. In the latter case the chiral and\ncontinuum limit of the scalar condensate do not commute, while for overlap\nfermions they do. For the topological susceptibility a universal continuum\nlimit is suggested, as is for the partition function and the Leutwyler-Smilga\nsum rule. In the heavy-quark force no difference is visible even at finite\ncoupling. Finally, a direct comparison between the complete overlap and the\nrooted staggered determinant yields evidence that their ratio is constant up to\n$O(a^2)$ effects."
    },
    {
        "anchor": "Cooling for instantons and the Wrath of Nahm: The dynamics of instantons and anti-instantons in lattice QCD can be studied\nby analysing the action and topological charge of configurations as they\napproach a self-dual or anti-self-dual state, i.e. a state in which S/S_0=|Q|.\nWe use cooling to reveal the semi-classical structure of the configurations we\nstudy. Improved actions which eliminate discretization errors up to and\nincluding O(a^4) are used to stabilise instantons as we cool for several\nthousand sweeps. An analogously improved lattice version of the continuum\nfield-strength tensor is used to construct a topological charge free from\nO(a^4) discretization errors. Values of the action and topological charge\nobtained with these improved operators approach mutually-consistent integer\nvalues to within a few parts in 10^4 after several hundred cooling sweeps.\nAnalysis of configurations with |Q| \\approx 1 and |Q| \\approx 2 supports the\nhypothesis that a self-dual |Q|=1 configuration cannot exist on the 4-torus.",
        "positive": "Simulating Full QCD with the Fixed Point Action: Due to its complex structure the parametrized fixed point action can not be\nsimulated with the available local updating algorithms. We constructed, coded,\nand tested an updating procedure with 2+1 light flavors, where the targeted\ns-quark mass is at its physical value while the u- and d-quarks should produce\npions lighter than 300MeV. In the algorithm a partially global gauge update is\nfollowed by several accept/reject steps, where parts of the determinant are\nswitched on gradually in the order of their expenses. The trial configuration\nthat is offered in the last, most expensive, stochastic accept/reject step\ndiffers from the original configuration by a Metropolis + over-relaxation gauge\nupdate over a sub-volume of ~(1.3 fm)^4. The acceptance rate in this\naccept/reject step is ~0.4. The code is optimized on different architectures\nand is running on lattices with L=1.2fm and 1.8fm at a resolution of a=0.15fm."
    },
    {
        "anchor": "What the Gribov copy tells on the confinment and the theory of dynamical\n  chiral symmetry breaking: We performed lattice Landau gauge QCD simulation on \\beta=6.0, 16^4, 24^4,\n32^4 and \\beta=6.4, 32^4, 48^4 and 56^4 by adopting the gauge fixing that\nminimizes the norm of the gauge field, and measured the running coupling by\nusing the gluon propagator and the ghost propagator. In view of ambiguity in\nthe vertex renormalization factor \\tilde Z_1 in the lattice, we adjust the\nnormalization of the running coupling by the perturbative QCD results near the\nhighest momentum point. It has a maximum \\alpha_s(q)~ 2.1(3) at around q=0.5\nGeV and decreases as q approaches 0, and the Kugo-Ojima parameter reached\n-0.83(2). The infrared exponent of the ghost propagator at 0.4GeV region is\n\\alpha_G=0.20 but there is an exceptional Gribov copy with \\alpha_G=0.27. The\nfeatures of the exceptional Gribov copy are investigated by measuring four\none-dimensional Fourier transform(1-d FT) of the gluon propagator transverse to\neach lattice axis. We observe, in general, correlation between absolute value\nof the Kugo-Ojima parameter and the degree of reflection positivity violation\nin the 1-d FT of the gluon propagator. The 1-d FT of the exceptional Gribov\ncopy has an axis whose gluon propagator manifestly violates reflection\npositivity, and the average of the Cartan subalgebra components of the\nKugo-Ojima parameter along this axis is consistent to -1. The running coupling\nof the enemble average shows a suppression at 0 momentum, but when the ghost\npropagator of the exceptional Gribov copy is adopted, the suppression\ndisappears and the data implies presence of the infrared fixed point\n\\alpha_s(0)~ 2.5(5) and \\kappa=0.5 suggested by the Dyson-Schwinger approach in\nthe multiplicative renormalizable scheme. Comparison with the SU(2) QCD and\nN_f=2 unquenched SU(3) QCD are also made.",
        "positive": "Novel Approaches to Renormalization Group Transformations in the\n  Continuum and on the Lattice: This thesis is about new methods of achieving RG transformations, in both a\ncontinuum spacetime background and on a lattice discretization thereof. The\nsubject is explored from the point of view of euclidean quantum field theory.\nAs a thesis grounded on the computational method of lattice simulation, I\nemphasize the role of lattice formulations throughout the work, especially in\nthe first two chapters. In the first, I describe the essential aspects of\nlattice theory and its symbiosis with RG. In the second, I present a new,\ncontinuous approach to RG on the lattice, based on a numerical tool called\nGradient Flow (GF). Simulation results from quartic scalar field theory in 2\nand 3 dimensions ($\\phi^4_d$) and 4-dimensional 12-flavor SU(3) gauge theory\nwill be presented. In the third and fourth chapters, the focus becomes more\nanalytic. Chapter 3 is an introductory review of Functional Renormalization\nGroup (FRG). In chapter 4, I introduce the concept of Stochastic RG (SRG) by\nworking out the relationship between FRG and stochastic processes."
    },
    {
        "anchor": "Charm (and bottom) baryons and charmonium excitations from the lattice: This report discusses some recent investigations of the heavy hadron spectra\nusing lattice QCD. The first half addresses multiple precision determinations\nof the masses of charm (and bottom) baryons. Recent lattice results in the\ntetraquark and the dibaryon sectors are also presented. The second half focuses\non new exploratory studies of the excited charmonium spectra in the vector and\nscalar channels. Along the way, lattice results are compared with the\nexperimental results, wherever they are available.",
        "positive": "Hutch++ and XTrace to Improve Stochastic Trace Estimation: We present the analysis of two recently proposed noise reduction techniques,\nHutch++ and XTrace, both based on inexact deflation. These methods were proven\nto have a better asymptotic convergence to the solution than the classical\nGirard-Hutchinson stochastic method. We applied these methods to the\ncomputation of the trace of the inverse of the Dirac operator with $O(a)$\nimproved Wilson fermions on the QCD ensemble generated by the RC$^{\\star}$\ncollaboration with $m_{\\pi}\\approx 400$ MeV and $V = 64\\times 32^3$.\nUnfortunately, we see no noise reduction with a moderate number of sources, and\nwe attempt an explanation of why this is the case. This study was part of the\neffort to evaluate isospin-breaking effects using the RM123 with C$^{\\star}$\nboundary conditions in an unquenched set-up."
    },
    {
        "anchor": "Pad\u00e9 and Pad\u00e9-Laplace Methods for masses and matrix elements: The problem of having to reconstruct the decay rates and corresponding\namplitudes of the single-exponential components of a noisy multi-exponential\nsignal is common in many other areas of physics and engineering besides lattice\nfield theory, and it can be helpful to study the methods devised and used for\nthat purpose in those contexts in order to get a better handle on the problem\nof extracting masses and matrix elements from lattice correlators. Here we\nconsider the use of Pad\\'e and Pad\\'e-Laplace methods, which have found wide\nuse in laser fluorescence spectroscopy and beyond, emphasizing the importance\nof using robust Pad\\'e approximants to avoid spurious poles. To facilitate the\naccurate evaluation of the Laplace transform required for the Pad\\'e-Laplace\nmethod, we also present a novel approach to the numerical quadrature of\nmulti-exponential functions.",
        "positive": "The rooted staggered determinant in the Schwinger model: We investigate the continuum limit of the rooted staggered action in the\n2-dimensional Schwinger model. We match both the unrooted and rooted staggered\ndeterminants with an overlap fermion determinant of two (one) flavors and a\nlocal pure gauge effective action by fitting the coefficients of the effective\naction and the mass of the overlap operator. The residue of this fit measures\nthe difference of the staggered and overlap fermion actions. We show that this\nresidue scales at least as O(a^2), implying that any difference, be it local or\nnon-local, between the staggered and overlap actions becomes irrelevant in the\ncontinuum limit. For the model under consideration here, this observation\njustifies the rooting procedure for the staggered sea quark action."
    },
    {
        "anchor": "The HotQCD Equation of State: We present results from recent calculations of the QCD equation of state by\nthe HotQCD Collaboration and review the implications for hydrodynamic modeling.\nThe equation of state of QCD at zero baryon density was calculated on a lattice\nof dimensions $32^3 \\times 8$ with $m_l = 0.1 m_s$ (corresponding to a pion\nmass of $\\sim$220 MeV) using two improved staggered fermion actions, p4 and\nasqtad. C alculations were performed along lines of constant physics using more\nthan 100M cpu-hours on BG/L supercomputers at LLNL, NYBlue, and SDSC. We\npresent paramete rizations of the equation of state suitable for input into\nhydrodynamics models of heavy ion collisions.",
        "positive": "Two-pion excited state contribution to pseudo-scalar correlators: We study multi-particle state contributions to the QCD two-point functions of\npseudo-scalar quark bilinears in a finite spatial volume. For sufficiently\nsmall quark masses one expects three-meson states with two additional pions at\nrest to have the lowest total energy after the ground state. Using chiral\nperturbation theory, we find the amplitude of this state to be too small to be\nseen in present-day lattice simulations. We speculate that curvature in the\neffective mass plot extracted from the pseudo-scalar density two-point function\ninstead corresponds to a genuine resonance, the \\pi(1300)."
    },
    {
        "anchor": "The Contribution of Novel CP Violating Operators to the nEDM using\n  Lattice QCD: In this talk, we motivate the calculation of the matrix elements of novel CP\nviolating operators, the quark EDM and the quark chromo EDM operators, within\nthe nucleon state using lattice QCD. These matrix elements, combined with the\nbound on the neutron EDM, would provide stringent constraints on beyond the\nstandard model physics, especially as the next generation of neutron EDM\nexperiments reduce the current bound. We then present our lattice strategy for\nthe calculation of these matrix elements, in particular we describe the use of\nthe Schr\\\"odinger source method to reduce the calculation of the 4-point to\n3-point functions needed to evaluate the quark chromo EDM contribution. We end\nwith a status report on the quality of the signal obtained in the lattice\ncalculations of the connected contributions to the quark chromo EDM operator\nand the pseudoscalar operator it mixes with under renormalization.",
        "positive": "Sea Quark Effects on the Strong Coupling Constant: We present results showing that the strong coupling constant measured in\ntwo-flavor full QCD with dynamical Kogut-Susskind quarks at $\\beta=5.7$ exhibit\na 15\\% increase due to sea quarks over that for quenched QCD at the scale\n$\\mu\\approx 7$GeV . (talk at lattice93)"
    },
    {
        "anchor": "Chiral corrections to the Roper mass: We analyze the quark mass dependence of the Roper mass to one-loop order in\nrelativistic baryon chiral perturbation theory. The loop integrals are\nevaluated using infrared regularization which preserves chiral symmetry and\nestablishes a chiral counting scheme. The derived chiral expansion of the Roper\nmass may prove useful for chiral extrapolations of lattice data. For couplings\nof natural size the quark mass dependence of the Roper mass is similar to the\none of the nucleon.",
        "positive": "Center Symmetry and Abelian Projection at Finite Temperature: At finite temperature, there is an apparent conflict between Abelian\nprojection and critical universality. For example, should the deconfinement\ntransition of an SU(2) gauge theory projected to U(1) lie in the Z(2)\nuniversality class of the parent SU(2) theory or in the U(1) universality\nclass? I prove that the projected theory lies in the universality class of the\nparent gauge theory. The mechanism is shown to be non-local terms in the\nprojected effective action involving Polyakov loops. I connect this to the\nrecent work by Dunne et al. on the deconfinement transition in the 2+1\ndimensional Georgi-Glashow model."
    },
    {
        "anchor": "O(a) improved Wilson quark action on anisotropic lattice: The $O(a)$ improved Wilson quark action on the anisotropic lattice is\ninvestigated. We carry out numerical simulations in the quenched approximation\nat three values of lattice spacing ($a_{\\sigma}^{-1}=1$--2 GeV) with the\nanisotropy $\\xi=a_{\\sigma}/a_{\\tau}=4$, where $a_{\\sigma}$ and $a_{\\tau}$ are\nthe spatial and the temporal lattice spacings, respectively. Using the\ndispersion relation of mesons, the bare anisotropy $\\gamma_F$ in the quark\naction is numerically tuned below the charm quark mass region with the\nstatistical accuracy of 1 % level. The systematic uncertainties in the\ncalibration are examined and found to be under control in the continuum limit.\nThen we compute the light hadron masses and find that they are consistent with\nthe result of the UKQCD Collaboration on the isotropic lattice. The effect of\nthe uncertainty in the calibration on the hadron spectrum for physical quark\nmasses is also found to be under control.",
        "positive": "Nucleon isovector structure functions in (2+1)-flavor QCD with domain\n  wall fermions: We report on numerical lattice QCD calculations of some of the low moments of\nthe nucleon structure functions. The calculations are carried out with gauge\nconfigurations generated by the RBC and UKQCD collaborations with (2+1)-flavors\nof dynamical domain wall fermions and the Iwasaki gauge action ($\\beta =\n2.13$). The inverse lattice spacing is $a^{-1} = 1.73$ GeV, and two spatial\nvolumes of ((2.7{\\rm fm})^3) and ((1.8 {\\rm fm})^3) are used. The up and down\nquark masses are varied so the pion mass lies between 0.33 and 0.67 GeV while\nthe strange mass is about 12 % heavier than the physical one. The structure\nfunction moments we present include fully non-perturbatively renormalized\niso-vector quark momentum fraction, (< x >_{u-d}), helicity fraction, (< x\n>_{\\Delta u - \\Delta d}), and transversity, (< 1 >_{\\delta u - \\delta d}), as\nwell as an unrenormalized twist-3 coefficient, (d_1). The ratio of the momentum\nto helicity fractions, (< x >_{u-d}/< x >_{\\Delta u - \\Delta d}), does not show\ndependence on the light quark mass and agrees well with the value obtained from\nexperiment. Their respective absolute values, fully renormalized, show\ninteresting trends toward their respective experimental values at the lightest\nquark mass. A prediction for the transversity, (0.7 < < 1 >_{\\delta u -\\delta\nd} < 1.1), in the (\\bar{\\rm MS}) scheme at 2 GeV is obtained. The twist-3\ncoefficient, (d_1), though yet to be renormalized, supports the perturbative\nWandzura-Wilczek relation."
    },
    {
        "anchor": "Inverse magnetic catalysis in QCD: We propose a physical mechanism for inverse magnetic catalysis, the\nsuppression of the chiral condensate by an external magnetic field in QCD\naround the critical temperature. We show that this effect, seen in lattice\nsimulations, is a result of how the sea quarks react to the magnetic field. We\nfind that the suppression of the condensate happens because the quark\ndeterminant can suppress low quark modes by ordering the Polyakov loop. This\nmechanism is particularly efficient around $T_c$ where the Polyakov loop\neffective potential is flat and the determinant can have a significant ordering\neffect. Our picture suggests that for the description of QCD in large magnetic\nfields it is crucial to properly capture the interaction between the Polyakov\nloop and the sea quarks, both in low-energy effective models and on the\nlattice.",
        "positive": "Volume Effects in Discrete beta functions: We calculate discrete beta functions corresponding to the two-lattice\nmatching for the 2D O(N) models and Dyson's hierarchical model. We describe and\nexplain finite-size effects such as the appearance of a nontrivial infrared\nfixed point that goes to infinity at infinite volume or the merging of an\ninfrared and an ultraviolet fixed point. We present extensions of the RG flows\nto the complex coupling plane. We discuss the possibility of constructing a\ncontinuous beta function from the discrete one by using functional conjugation\nmethods. We briefly discuss the relevance of these findings for the search of\nnontrivial fixed points in multiflavor lattice gauge theory models."
    },
    {
        "anchor": "Lattice measurement of $B_{B_s}$ with a chiral light quark action: The computation on the lattice of the bag parameter $B_{B_s}$ associated to\nthe $B_s - \\bar{B_s}$ mixing amplitude in the Standard Model is presented. The\nestimation has been made by combining the static limit of HQET and the\nNeuberger light quark action which preserves the chiral symmetry on the\nlattice. We find $B^{\\bar{MS}}{stat}}_{B_s}(m_b)=0.92(3)$.",
        "positive": "A lattice NRQCD computation of the bag parameters for $\u0394B$ = 2\n  operators: We present an update of our NRQCD calculation of $B_B$ at $\\beta$=5.9 with\nincreased statistics. We also discuss a calculation of $B_S$, which is relevant\nto the width difference in the $B_s-\\bar{B}_s$ mixing."
    },
    {
        "anchor": "Logarithmic Corrections in the 2D XY Model: Using two sets of high-precision Monte Carlo data for the two-dimensional XY\nmodel in the Villain formulation on square $L \\times L$ lattices, the scaling\nbehavior of the susceptibility $\\chi$ and correlation length $\\xi$ at the\nKosterlitz-Thouless phase transition is analyzed with emphasis on\nmultiplicative logarithmic corrections $(ln L)^{-2r}$ in the finite-size\nscaling region and $(ln \\xi)^{-2r}$ in the high-temperature phase near\ncriticality, respectively. By analyzing the susceptibility at criticality on\nlattices of size up to $512^2$ we obtain $r = -0.0270(10)$, in agreement with\nrecent work of Kenna and Irving on the the finite-size scaling of Lee-Yang\nzeros in the cosine formulation of the XY model. By studying susceptibilities\nand correlation lengths up to $\\xi \\approx 140$ in the high-temperature phase,\nhowever, we arrive at quite a different estimate of $r = 0.0560(17)$, which is\nin good agreement with recent analyses of thermodynamic Monte Carlo data and\nhigh-temperature series expansions of the cosine formulation.",
        "positive": "Some Cautionary Remarks on Abelian Projection and Abelian Dominance: Some critical remarks are presented, concerning the abelian projection theory\nof quark confinement."
    },
    {
        "anchor": "$\\mathcal PT$ symmetry, pattern formation, and finite-density QCD: A longstanding issue in the study of quantum chromodynamics (QCD) is its\nbehavior at nonzero baryon density, which has implications for many areas of\nphysics. The path integral has a complex integrand when the quark chemical\npotential is nonzero and therefore has a sign problem, but it also has a\ngeneralized $\\mathcal PT$ symmetry. We review some new approaches to $\\mathcal\nPT$-symmetric field theories, including both analytical techniques and methods\nfor lattice simulation. We show that $\\mathcal PT$-symmetric field theories\nwith more than one field generally have a much richer phase structure than\ntheir Hermitian counterparts, including stable phases with patterning behavior.\nThe case of a $\\mathcal PT$-symmetric extension of a $\\phi^4$ model is\nexplained in detail. The relevance of these results to finite density QCD is\nexplained, and we show that a simple model of finite density QCD exhibits a\npatterned phase in its critical region.",
        "positive": "A new approach to Ginsparg-Wilson fermions: We expand the most general lattice Dirac operator D in a basis of simple\noperators. The Ginsparg-Wilson equation turns into a system of coupled\nquadratic equations for the expansion coefficients. Our expansion of D allows\nfor a natural cutoff and the remaining quadratic equations can be solved\nnumerically. The procedure allows to find Dirac operators which obey the\nGinpsparg-Wilson equation with arbitrary precision."
    },
    {
        "anchor": "Moving Multi-Channel Systems in a Finite Volume with Application to\n  Proton-Proton Fusion: The spectrum of a system with multiple channels composed of two hadrons with\nnonzero total momentum is determined in a finite cubic volume with periodic\nboundary conditions using effective field theory methods. The results presented\nare accurate up to exponentially suppressed corrections in the volume due to\nthe finite range of hadronic interactions. The formalism allows one to\ndetermine the phase shifts and mixing parameters of pipi-KK isosinglet coupled\nchannels directly from Lattice Quantum Chromodynamics. We show that the\nextension to more than two channels is straightforward and present the result\nfor three channels. From the energy quantization condition, the volume\ndependence of electroweak matrix elements of two-hadron processes is extracted.\nIn the non-relativistic case, we pay close attention to processes that mix the\n1S0-3S1 two-nucleon states, e.g. proton-proton fusion (pp -> d+ e^+ + nu_e),\nand show how to determine the transition amplitude of such processes directly\nfrom lattice QCD.",
        "positive": "Harmonic Oscillator Prepotentials in SU(2) Lattice Gauge Theory: We write the SU(2) lattice gauge theory Hamiltonian in (d+1) dimensions in\nterms of prepotentials which are the SU(2) fundamental doublets of harmonic\noscillators. The Hamiltonian in terms of prepotentials has $SU(2) \\otimes U(1)$\nlocal gauge invariance. In the strong coupling limit, the color confinement in\nthis formulation is due to the U(1) gauge group. We further solve the $SU(2)\n\\otimes U(1)$ Gauss law to characterize the physical Hilbert space in terms of\na set of gauge invariant integers. We also obtain certain novel gauge invariant\noperators in terms of the above oscillators. The corresponding prepotential\nformulation of SU(N) lattice gauge theory is also simple and discussed."
    },
    {
        "anchor": "Charmed pseudoscalar decay constants on three-flavour CLS ensembles with\n  open boundaries: We determine the masses and pseudoscalar decay constants of D and D_s mesons\nemploying lattice QCD with non-perturbatively O(a) improved Wilson quarks and a\ntree-level Symanzik-improved gauge action. Our analysis is based on the\nlarge-volume N_f=2+1 ensembles using open boundary conditions, generated within\nthe CLS effort. The status of results presented here covers two lattice\nspacings, a ~ 0.0854 fm and a ~ 0.0644 fm, and pion masses varied from 420 to\n200 MeV. We also report on our implementation of distance preconditioning for\nthe calculation of heavy quark propagators and discuss the impact of the\nresulting accuracy improvements on the extraction of charmed meson masses and\ndecay constants. This is part of a continuing analysis by the RQCD and ALPHA\nCollaborations, aiming at a stable continuum extrapolation using several\nlattice spacings. To extrapolate to the physical masses, we follow both, the\n(2*m_l+m_s)=const. and the m_s=const. line in parameter space.",
        "positive": "Chiral behavior of $K \\to \u03c0l \u03bd$ decay form factors in lattice QCD\n  with exact chiral symmetry: We calculate the form factors of the $K \\to \\pi l \\nu$ semileptonic decays in\nthree-flavor lattice QCD, and study their chiral behavior as a function of the\nmomentum transfer and the Nambu-Goldstone boson masses. Chiral symmetry is\nexactly preserved by using the overlap quark action, which enables us to\ndirectly compare the lattice data with chiral perturbation theory (ChPT). We\ngenerate gauge ensembles at a lattice spacing of 0.11fm with four pion masses\ncovering 290-540 MeV and a strange quark mass m_s close to its physical value.\nBy using the all-to-all quark propagator, we calculate the vector and scalar\nform factors with high precision. Their dependence on m_s and the momentum\ntransfer is studied by using the reweighting technique and the twisted boundary\nconditions for the quark fields. We compare the results for the semileptonic\nform factors with ChPT at next-to-next-to leading order in detail. While many\nlow-energy constants appear at this order, we make use of our data of the light\nmeson electromagnetic form factors in order to control the chiral\nextrapolation. We determine the normalization of the form factors as f_+(0) =\n0.9636(36)(+57/-35), and observe reasonable agreement of their shape with\nexperiment."
    },
    {
        "anchor": "An unquenched lattice QCD calculation of the mass of the bottom quark: We compute the b quark mass from dynamical lattice QCD with clover quarks.\nThe calculation is done at a fixed lattice spacing with sea quark masses as low\nas half the strange quark mass. Our final result is m_b(m_b} = 4.25(2)(11) GeV,\nwhere the first error is statistical and the last error is the systematic\nuncertainty.",
        "positive": "Two-flavor QCD at finite quark or isospin density: We exploit analytic continuation to prolongate to the region of real chemical\npotentials the (pseudo)critical lines of QCD with two degenerate staggered\nfermions at nonzero temperature and quark or isospin density obtained in the\nregion of imaginary chemical potentials. We determine the curvatures at zero\nchemical potential and quantify the deviation between the cases of finite quark\nand of finite isospin chemical potential. In both circumstances deviations from\na quadratic dependence of the pseudocritical lines on the chemical potential\nare clearly seen. We try different extrapolations and, for the nonzero isospin\nchemical potential, confront them with the results of direct Monte Carlo\nsimulations. We also find that, as for the finite quark chemical potential, an\nimaginary isospin chemical potential can strengthen the transition till turning\nit into strong first order."
    },
    {
        "anchor": "Towards charged hadron polarizabilities from four-point functions in\n  lattice QCD: We show how to compute electromagnetic polarizabilities of charged hadrons\nusing four-point functions in lattice QCD. The low-energy behavior of Compton\nscattering amplitude is matched to matrix elements of current-current\ncorrelation functions on the lattice. Working in momentum space, formulas for\nelectric polarizability ($\\alpha_E$) and magnetic polarizability ($\\beta_M$)\nare derived for both charged pion and proton. Lattice four-point correlation\nfunctions are constructed from quark and gluon fields to be used in Monte-Carlo\nsimulations. The content of the functions is assessed in detail and specific\nprescriptions are given to isolate the polarizabilities. The connected\nquark-line diagrams can be done today as a small lattice project. The\ndisconnected diagrams are more challenging but are within reach of dedicated\nresources for medium to large lattice projects. We also draw attention to the\npotential of four-point functions as a multi-purpose tool for hadron structure.",
        "positive": "Update on the 2+1+1 flavor QCD equation of state with HISQ: We present recent results on the QCD equation of state with 2+1+1 flavors of\nhighly improved staggered quarks (HISQ). We focus on three sets of ensembles\nwith temporal extent 6, 8 and 10, that reach up to temperatures of 967, 725 and\n580 MeV, respectively. The strange and charm quark masses are tuned to the\nphysical values and the light quarks mass is set to one fifth of the strange.\nThis corresponds to a Goldstone pion of about 300 MeV."
    },
    {
        "anchor": "Review on String Breaking - the Query in Quest of the Evidence: Considerable progress has been achieved recently in the observation of string\nbreaking within non-Abelian Higgs models, by use of multi-channel methods\nallowing for broken string states. Similarly, in pure gauge theory this\napproach has been shown to reveal string breaking for color charges in the\nadjoint represaentation. For QCD with dynmical fermions, one needs substantial\nprogress in noise reduction, however, to render such techniques viable.",
        "positive": "String tension from gauge invariant Magnetic Monopoles: We investigate the relationship between colour confinement and the monopoles\nderived from the Cho-Duan-Ge decomposition. These monopoles, unlike Dirac and\n't Hooft monopoles, do not require a singular gauge field and are defined for\nany choice of gauge (and are not just restricted to, for example, the maximum\nAbelian gauge). The Abelian decomposition is defined in terms of a colour field\n$n$; the principle novelty of our study is that we have used a unique\ndefinition of this field in terms of the eigenvectors of the Wilson Loop. This\nallows us to investigate the relationship between the gauge invariant monopoles\nand confinement both analytically and numerically, as well as retaining the\nmaximal possible symmetry within the colour field so that it is able to see all\nthe monopoles in an SU($N_C$) calculation.\n  We describe how the Abelian decomposition is related to the Wilson Loop, so\nthat the string tension may be calculated from the field strength related to\nthe decomposed (or restricted) Abelian field. We discuss the structures in the\ncolour field which may cause an area law in the Wilson Loop, which turn out to\nbe magnetic monopoles. If these monopoles are present, they will lead to an\narea law scaling of the Wilson Loop and thus be at least partially responsible\nfor confinement.\n  We search for these monopoles in quenched lattice QCD. We show that the\nstring tension is dominated by peaks in the restricted field strength, at least\nsome of which are located close to structures in the colour field consistent\nwith with theoretical expectations for the monopoles. We show that the string\ntension extracted from the monopole contribution to the restricted field is\nclose to that of the entire original field; again suggesting that confinement\ncan at least partially be explained in terms of these monopoles."
    },
    {
        "anchor": "Diagrammatic representation of scalar QCD and sign problem at nonzero\n  chemical potential: We consider QCD at strong coupling with scalar quarks coupled to a chemical\npotential. Performing the link integrals we present a diagrammatic\nrepresentation of the path integral weight. It is based on mesonic and baryonic\nbuilding blocks, in close analogy to fermionic QCD. Likewise, the baryon loops\nare subject to a manifest conservation of the baryon number. The sign problem\nis expected to disappear in this representation and we do confirm this for\nthree flavors, where a scalar baryon can be built and thus a dependence on the\nchemical potential occurs. For higher flavor number we analyse examples for a\npotential sign problem in the baryon sector and conjecture that all weights are\npositive upon exploring the current conservation of each flavor.",
        "positive": "Scale Setting and Topological Observables in Pure SU(2) LGT: In this dissertation, we investigate the approach of pure SU(2) lattice gauge\ntheory to its continuum limit using the deconfinement temperature, six gradient\nscales, and six cooling scales. We find that cooling scales exhibit similarly\ngood scaling behavior as gradient scales, while being computationally more\nefficient. In addition, we estimate systematic error in continuum limit\nextrapolations of scale ratios by comparing standard scaling to asymptotic\nscaling. Finally we study topological observables in pure SU(2) using cooling\nto smooth the gauge fields, and investigate the sensitivity of cooling scales\nto topological charge. We find that large numbers of cooling sweeps lead to\nmetastable charge sectors, without destroying physical instantons, provided the\nlattice spacing is fine enough and the volume is large enough. Continuum limit\nestimates of the topological susceptibility are obtained, of which we favor\n$\\chi^{1/4}/T_c = 0.643(12)$. Differences between cooling scales in different\ntopological sectors turn out to be too small to be detectable within our\nstatistical error."
    },
    {
        "anchor": "High temperature $U(1)_A$ breaking in the chiral limit: We solve the long-standing problem concerning the fate of the chiral $U(1)_A$\nsymmetry in QCD-like theories at high temperature in the chiral limit. We\nintroduce a simple instanton based random matrix model that precisely\nreproduces the properties of the lowest part of the lattice overlap Dirac\nspectrum. We show that in the chiral limit the instanton gas splits into a free\ngas component with a density proportional to $m^{N_f}$ and a gas of\ninstanton-antiinstanton molecules. While the latter do not influence the chiral\nproperties, for any nonzero quark mass the free gas component produces a\nsingular spectral peak at zero that dominates Banks-Casher type spectral sums.\nBy calculating these we show that the difference of the pion and delta\nsusceptibility vanishes only for three or more massless flavors, however, the\nchiral condensate is zero already for two massless flavors",
        "positive": "Bosonic stringlike behavior and the Ultraviolet filtering of QCD: The gluonic action density is calculated in static mesons at finite\ntemperature just below the deconfinement point. Our focus is to elucidate the\nrole of vacuum ultraviolet fluctuations which are filtered using an improved\nsmearing algorithm. In the intermediate source separation distance, where the\nfree string picture poorly describes the flux tube width profile, we find upon\nreducing the vacuum action towards the classical instanton vacuum, the\ncharacteristics of the flux tube converge and compare favorably with the\npredictions of the free bosonic string. This result establishes a connection\nbetween the free string action and vacuum gauge fields and reveals the\nimportant role of ultraviolet physics in understanding the lattice data at this\ntemperature scale. As a by-product of these calculations, we find the\nbroadening of the QCD flux tube to be independent of the ultraviolet filtering\nat large distances. Our results exhibit a linearly divergent pattern in\nagreement with the string picture predictions."
    },
    {
        "anchor": "Partial wave decomposition on the lattice and its applications to the\n  HAL QCD method: The approximated partial wave decomposition method to the discrete data on a\ncubic lattice, developed by C. W. Misner, is applied to the calculation of\n$S$-wave hadron-hadron scatterings by the HAL QCD method in lattice QCD. We\nconsider the Nambu-Bethe-Salpeter (NBS) wave function for the spin-singlet\n$\\Lambda_c N$ system calculated in the $(2+1)$-flavor QCD on a\n$(32a~\\mathrm{fm})^3$ lattice at the lattice spacing $a\\simeq0.0907$ fm and\n$m_\\pi \\simeq 700$ MeV. We find that the $l=0$ component can be successfully\nextracted by Misner's method from the NBS wave function projected to $A_1^+$\nrepresentation of the cubic group, which contains small $l\\ge 4$ components.\nFurthermore, while the higher partial wave components are enhanced so as to\nproduce significant comb-like structures in the conventional HAL QCD potential\nif the Laplacian approximated by the usual second order difference is applied\nto the NBS wave function, such structures are found to be absent in the\npotential extracted by Misner's method, where the Laplacian can be evaluated\nanalytically for each partial wave component. Despite the difference in the\npotentials, two methods give almost identical results on the central values and\non the magnitude of statistical errors for the fits of the potentials, and\nconsequently on the scattering phase shifts. This indicates not only that\nMisner's method works well in lattice QCD with the HAL QCD method but also that\nthe contaminations from higher partial waves in the study of $S$-wave\nscatterings are well under control even in the conventional HAL QCD method. It\nwill be of interest to study interactions in higher partial wave channels in\nthe HAL QCD method with Misner's decomposition, where the utility of this new\ntechnique may become clearer.",
        "positive": "Heavy Quark Physics and Lattice QCD: I review recent progress made on heavy quark physics on the lattice."
    },
    {
        "anchor": "Spin-1 fields and RG flows in 4 dimensions: The most general local, classically scale invariant, perturbatively\nrenormalizable, globally $SU(N)$ invariant Lagrangian is constructed for spin-1\nfields in 4 dimensions. The total number of independent couplings is 7 and the\n1-loop $\\beta$-functions are computed in the MSbar scheme. A number of\nasymptotically free RG flows are identified corresponding to non-trivial QFTs.\nNone of these are gauge theories. The details of the large-$N$ limit are also\nworked out and it is shown that the RG phase space is qualitatively similar for\nall $N>5$ including the $N\\to\\infty$ limit.",
        "positive": "Multi--Layer Structure in the Strongly Coupled 5D Abelian Higgs Model: We explore the phase diagram of the five-dimensional anisotropic Abelian\nHiggs model by Monte Carlo simulations. In particular, we study the transition\nbetween the confining phase and the four dimensional layered Higgs phase. We\nfind that, in a certain region of the lattice parameter space, this transition\ncan be first order and that each layer moves into the Higgs phase independently\nof the others (decoupling of layers). As the Higgs couplings vary, we find,\nusing mean field techniques, that this transition may probably become second\norder."
    },
    {
        "anchor": "Predictions from Lattice QCD: In the past year, we calculated with lattice QCD three quantities that were\nunknown or poorly known. They are the $q^2$ dependence of the form factor in\nsemileptonic $D\\to Kl\\nu$ decay, the decay constant of the $D$ meson, and the\nmass of the $B_c$ meson. In this talk, we summarize these calculations, with\nemphasis on their (subsequent) confirmation by experiments.",
        "positive": "The phase diagram of a gauge theory with fermionic baryons: The fermion-sign problem at finite density is a persisting challenge for\nMonte-Carlo simulations. Theories that do not have a sign problem can provide\nvaluable guidance and insight for physically more relevant ones that do.\nReplacing the gauge group SU(3) of QCD by the exceptional group G2, for\nexample, leads to such a theory. It has mesons as well as bosonic and fermionic\nbaryons, and shares many features with QCD. This makes the G2 gauge theory\nideally suited to study general properties of dense, strongly-interacting\nmatter, including baryonic and nuclear Fermi pressure effects. Here we present\nthe first-ever results from lattice simulations of G2 QCD with dynamical\nfermions, providing a first explorative look at the phase diagram of this\nQCD-like theory at finite temperature and baryon chemical potential."
    },
    {
        "anchor": "Lyapunov Spectra in SU(2) Lattice Gauge Theory: We develop a method for calculating the Lyapunov characteristic exponents of\nlattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is\nobtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with\nlattice size is found.",
        "positive": "The gluino-glue particle and relevant scales for the simulations of\n  supersymmetric Yang-Mills theory: Supersymmetric Yang-Mills theory is in several respects different from QCD\nand pure Yang-Mills theory. Therefore, a reinvestigation of the scales, at\nwhich finite size effects and lattice artifacts become relevant, is necessary.\nBoth, finite size effects and lattice artifacts, induce a breaking of\nsupersymmetry. In view of the unexpected mass gap between bosonic and fermionic\nparticles an estimation of these effects is essential."
    },
    {
        "anchor": "Vector particle scattering on the lattice: In this work, we present an explicit form of the Luescher equation and\nconsider the construction of the operators in different irreducible\nrepresentations for the case of scattering of two vector particles. The\nformalism is applied to scalar QED in the Higgs Phase, where the $U(1)$ gauge\nboson acquires mass.",
        "positive": "Lattice Chiral Fermions: I review the ongoing attempts to define chiral gauge theories using the\nlattice regularization."
    },
    {
        "anchor": "$\u03b7$ and $\u03b7^\\prime$ masses and decay constants: We present preliminary results for the masses and decay constants of the\n$\\eta$ and $\\eta^\\prime$ mesons using CLS $N_f = 2+1$ ensembles. One of the\nmajor challenges in these calculations are the large statistical fluctuations\ndue to disconnected quark loops. We tackle these by employing a combination of\nnoise reduction techniques which are tuned to minimize the statistical error at\na fixed cost. On the analysis side we carefully assess excited states\ncontributions by using a direct fit approach.",
        "positive": "Evidence for a new $SU(4)$ symmetry with $J=2$ mesons: Recently, a new symmetry of mesons has been found upon truncation of the\nquasi-zero modes of the Overlap Dirac operator in lattice simulations. Namely,\nthe $\\rho,\\rho',\\omega,\\omega',a_1, b_1,h_1$ and possibly $f_1$ $J=1$ mesons\nget degenerate after removal of the quasi-zero modes. This emergent symmetry\nhas been established to be $SU(4)\\supset SU(2)_L \\times SU(2)_R \\times U(1)_A$.\nIt is higher than the symmetry of the QCD Lagrangian and provides not only a\nmixing of quarks of given chirality in the isospin space, but also the mixing\nof left-handed and right-handed components. Here we study, with the Overlap\nDirac operator, the isovector $J=2$ mesons upon the quasi-zero mode reduction\nand observe a similar degeneracy. This result further supports the $SU(4)$\nsymmetry in mesons of given spin $J \\geq 1$."
    },
    {
        "anchor": "Lattice Regularization of Reduced K\u00e4hler-Dirac Fermions and\n  Connections to Chiral Fermions: We show how a path integral for reduced K\\\"{a}hler-Dirac fermions suffers\nfrom a phase ambiguity associated with the fermion measure that is an analog of\nthe measure problem seen for chiral fermions. However, unlike the case of\nchiral symmetry, a doubler free lattice action exists which is invariant under\nthe corresponding onsite symmetry. This allows for a clear diagnosis and\nsolution to the problem using mirror fermions resulting in a unique gauge\ninvariant measure. By introducing an appropriate set of Yukawa interactions\nwhich are consistent with 't Hooft anomaly cancellation we conjecture the\nmirrors can be decoupled from low energy physics. Moreover, the minimal such\nK\\\"{a}hler-Dirac mirror model yields a light sector which corresponds, in the\nflat space continuum limit, to the Pati-Salam GUT model.",
        "positive": "Mass renormalisation for improved staggered quarks: Improved staggered quark actions are designed to suppress flavour changing\nstrong interactions. We discuss the perturbation theory for this type of\nactions and show the improvements to reduce the quark mass renormalisation\ncompared to naive staggered quarks. The renormalisations are of similar size as\nfor Wilson quarks."
    },
    {
        "anchor": "Lattice QCD Study for Gluon Propagator and Gluon Spectral Function: We study the gluon propagator in the Landau gauge in SU(3) lattice QCD at\n$\\beta$=5.7, 5.8 and 6.0 at the quenched level. The Euclidean Landau-gauge\ngluon propagator $D(r)\\equiv D_{\\mu\\mu}^{aa}(x)/24$ is found to be well\ndescribed by four-dimensional Yukawa-type function $e^{-mr}/r$ in the infrared\nand intermediate region of $r \\equiv (x_\\mu x_\\mu)^{1/2}$ = 0.1 $\\sim$ 1.0fm.\nThe infrared effective gluon mass is obtained as $m \\simeq$ 600MeV. Associated\nwith the 4D Yukawa-type gluon propagator, we derive analytical expressions for\nthe zero-spatial-momentum propagator $D_0(t)$, the effective mass $M_{\\rm\neff}(t)$, and the spectral function $\\rho(\\omega)$ of the gluon field.\nRemarkably, the obtained gluon spectral function $\\rho(\\omega)$ is almost\nnegative definite, except for a positive $\\delta$-functional peak at\n$\\omega=m$. Since the Yukawa-type propagation indicates a three-dimensional\nspace-time character, we consider a hypothesis of an effective dimensional\nreduction by generalized Parisi-Sourlas mechanism in a stochastic\ncolor-magnetic vacuum of infrared QCD.",
        "positive": "Beyond the Thouless energy: The distribution and the correlations of the small eigenvalues of the Dirac\noperator are described by random matrix theory (RMT) up to the Thouless energy\n$E_c\\propto 1/\\sqrt{V}$, where $V$ is the physical volume. For somewhat larger\nenergies, the same quantities can be described by chiral perturbation theory\n(chPT). For most quantities there is an intermediate energy regime, roughly\n$1/V<E<1/\\sqrt{V}$, where the results of RMT and chPT agree with each other. We\ntest these predictions by constructing the connected and disconnected scalar\nsusceptibilities from Dirac spectra obtained in quenched SU(2) and SU(3)\nsimulations with staggered fermions for a variety of lattice sizes and coupling\nconstants. In deriving the predictions of chPT, it is important to take into\naccount only those symmetries which are exactly realized on the lattice."
    },
    {
        "anchor": "Center vortices and k-strings: The vortex contribution to the $k$-string tensions is computed for SU($N$)\ngauge theories. We deduce the surface densities needed to reproduce the sine\nscaling and the Casimir scaling formulae, recently obtained from numerical\nsimulations on the lattice. We find that such densities need to grow linearly\nin $N$, which in turn suggests that the vortex scenario can hardly reproduce\nthe physics of confinement at large $N$.",
        "positive": "Thermal phase transitions in rotating QCD with dynamical quarks: Relativistic rotation causes a change of QCD critical temperatures. Various\nphenomenological and effective models predict a decrease of the critical\ntemperatures in rotating QCD. Nevertheless, lattice simulations showed that the\ncritical temperature in gluodynamics increases due to rotation. We extend the\nlattice study to the theory with dynamical fermions. We present the first\nlattice results for rotating QCD with $N_f=2$ dynamical clover-improved Wilson\nquarks. We also study separately the effect of rotation on gluonic and\nfermionic degrees of freedom. It is shown that separate rotations of gluons and\nfermions have opposite effects on the critical temperatures. In aggregate, the\npseudo-critical temperatures in QCD increase with angular velocity. Dependence\nof the results on the pion mass is also discussed."
    },
    {
        "anchor": "Chiral spin symmetry and hot QCD: In this talk we overview main results indicating existence in QCD of three\nqualitatively different regimes connected by smooth crossovers upon heating: a\nhadron gas, a stringy fluid and a quark-gluon plasma. In the combined large N_c\nand chiral limit these regimes likely become distinct phases separated by phase\ntransitions: a chiral restoration phase transition around T_{ch} ~ 130 MeV and\na deconfinement phase transition around T_d ~ 300 MeV. It should be an\nimportant task to verify this issue on the lattice. We will introduce a chiral\nspin symmetry, which is a symmetry of the electric part of electrodynamics and\nof QCD with light quarks. It is realized approximately in QCD above the chiral\nrestoration crossover and disappears in the QGP regime. The center symmetry of\nthe pure glue action and the chiral spin symmetry of the electric part of the\nQCD Lagrangian with light quarks are complementary to distinguish the confining\nregime and its disappearance. We also address other lattice evidences for\nstringy fluid: hadron resonances extracted from the lattice correlators;\nbreakdown of the thermal perturbation theory at T < ~ 600 MeV and fluctuations\nof conserved charges that point out the N_c scaling above T ~ 155 MeV.",
        "positive": "The 1 Teraflops QCDSP computer: The QCDSP computer (Quantum Chromodynamics on Digital Signal Processors) is\nan inexpensive, massively parallel computer intended primarily for simulations\nin lattice gauge theory. Currently, two large QCDSP machines are in full-time\nuse: an 8,192 processor, 0.4 Teraflops machine at Columbia University and an\n12,288 processor, 0.6 Teraflops machine at the RIKEN-BNL Research Center at\nBrookhaven National Laboratory. We describe the design process, architecture,\nsoftware and current physics projects of these computers."
    },
    {
        "anchor": "A Study of the $N=2$ Kazakov-Migdal Model: We study numerically the SU(2) Kazakov-Migdal model of `induced QCD'. In\ncontrast to our earlier work on the subject we have chosen here {\\it not} to\nintegrate out the gauge fields but to keep them in the Monte Carlo simulation.\nThis allows us to measure observables associated with the gauge fields and\nthereby address the problem of the local $Z_2$ symmetry present in the model.\nWe confirm our previous result that the model has a line of first order phase\ntransitions terminating in a critical point. The adjoint plaquette has a clear\ndiscontinuity across the phase transition, whereas the plaquette in the\nfundamental representation is always zero in accordance with Elitzur's theorem.\nThe density of small $Z_2$ monopoles shows very little variation and is always\nlarge. We also find that the model has extra local U(1) symmetries which do not\nexist in the case of the standard adjoint theory. As a result, we are able to\nshow that two of the angles parameterizing the gauge field completely decouple\nfrom the theory and the continuum limit defined around the critical point can\ntherefore not be `QCD'.",
        "positive": "Dynamical lattice computation of the Isgur-Wise functions tau_{1/2} and\n  tau_{3/2}: We perform a two-flavor dynamical lattice computation of the Isgur-Wise\nfunctions tau_{1/2} and tau_{3/2} at zero recoil in the static limit. We find\ntau_{1/2}(1) = 0.297(26) and tau_{3/2}(1) = 0.528(23) fulfilling Uraltsev's sum\nrule by around 80%. We also comment on a persistent conflict between theory and\nexperiment regarding semileptonic decays of B mesons into orbitally excited P\nwave D mesons, the so-called \"1/2 versus 3/2 puzzle\", and we discuss the\nrelevance of lattice results in this context."
    },
    {
        "anchor": "Baryon resonances and hadronic interactions in a finite volume: In a finite volume, resonances and multi-hadron states are identified by\ndiscrete energy levels. When comparing the results of lattice QCD calculations\nto scattering experiments, it is important to have a way of associating the\nenergy spectrum of the finite-volume lattice with the asymptotic behaviour of\nthe S-matrix. A new technique for comparing energy eigenvalues with scattering\nphase shifts is introduced, which involves the construction of an exactly\nsolvable matrix Hamiltonian model. The model framework is applied to the case\nof $\\Delta\\rightarrow N\\pi$ decay, but is easily generalized to include\nmulti-channel scattering. Extracting resonance parameters involves matching the\nenergy spectrum of the model to that of a lattice QCD calculation. The\nresulting fit parameters are then used to generate phase shifts. Using a sample\nset of pseudodata, it is found that the extraction of the resonance position is\nstable with respect to volume for a variety of regularization schemes, and\ncompares favorably with the well-known Luescher method. The model-dependence of\nthe result is briefly investigated.",
        "positive": "Fermions, quantum gravity and holography in two dimensions: We study a model comprising $N$ flavors of K\\\"ahler Dirac fermion propagating\non a triangulated two dimensional disk which is constrained to have a negative\naverage bulk curvature. Dirichlet boundary conditions are chosen for the\nfermions. Quantum fluctuations of the geometry are included by summing over all\npossible triangulations consistent with these constraints. We show in the limit\n$N\\to \\infty$ that the partition function is dominated by a regular\ntriangulation of two dimensional hyperbolic space. We use strong coupling\nexpansions and Monte Carlo simulation to show that in this limit boundary\ncorrelators of the fermions have a power law dependence on boundary separation\nas one expects from holography. However we argue that this behavior breaks down\nfor any finite number of massive fields in the thermodynamic limit and quantum\nfluctuations of the bulk geometry drive the theory into a non-holographic\nphase. In contrast, for massless fermions we find evidence that the boundary is\nconformal even for finite $N$. This is consistent with theoretical results in\nquantum Liouville theory."
    },
    {
        "anchor": "Thermalization of Yang-Mills theory in a $(3+1)$ dimensional small\n  lattice system: We study the real-time evolution of SU($2$) Yang-Mills theory in a $(3+1)$\ndimensional small lattice system after interaction quench. We numerically solve\nthe Schr{\\\"o}dinger equation with the Kogut-Susskind Hamiltonian in the\nphysical Hilbert space obtained by solving Gauss law constraints. We observe\nthe thermalization of a Wilson loop to the canonical state; the relaxation time\nis insensitive to the coupling strength, and estimated as $\\tau_{\\rm eq}\\sim\n2\\pi/T$ with temperatures $T$ at steady states. We also compute the vacuum\npersistence probability (the Loschmidt echo) to understand the relaxation from\nthe dynamics of the wave function.",
        "positive": "Phase structure of thermal lattice QCD with N_f=2 twisted mass Wilson\n  fermions: We present numerical results for the phase diagram of lattice QCD at finite\ntemperature in the formulation with twisted mass Wilson fermions and a\ntree-level Symanzik-improved gauge action. Our simulations are performed on\nlattices with temporal extent N_\\tau=8, and lattice coupling \\beta ranging from\nstrong coupling to the scaling domain. Covering a wide range in the space\nspanned by the lattice coupling \\beta and the hopping and twisted mass\nparameters \\kappa and \\mu, respectively, we obtain a comprehensive picture of\nthe rich phase structure of the lattice theory. In particular, we verify the\nexistence of an Aoki phase in the strong coupling region and the realisation of\nthe Sharpe-Singleton scenario at intermediate couplings. In the weak coupling\nregion we identify the phase boundary for the physical finite temperature phase\ntransition/crossover. Its shape in the three-dimensional parameter space is\nconsistent with Creutz's conjecture of a cone-shaped thermal transition\nsurface."
    },
    {
        "anchor": "Taste symmetry and QCD thermodynamics with improved staggered fermions: Taste symmetry violations in staggered fermion formulations correlate\nstrongly with the cut-off (lattice spacing) dependence in thermodynamic\nquantities. Better taste symmetry on the lattice can be achieved either by\ndecreasing the lattice spacing and going to larger temporal extent in\nfinite-temperature calculations, or by further improving the action. The highly\nimproved staggered quark (HISQ) action offers a further degree of improvement\nand substantially reduces taste violations. We report on our studies of the 2+1\nflavor QCD thermodynamics with the HISQ/tree action. By systematically\ncomparing HISQ/tree, asqtad, p4 and stout calculations we quantify how the\ncut-off effects manifest themselves in different thermodynamic quantities,\nincluding the renormalized Polyakov loop, chiral condensate, various\nfluctuations and correlations of conserved charges. The implications for the\nequation of state and a comparison to the hadron resonance gas model are also\ndiscussed. The chiral aspects of the finite-temperature transition are\ndiscussed in the companion HotQCD contribution [1].",
        "positive": "Single flavour filtering for RHMC in BQCD: Filtering algorithms for two degenerate quark flavours have advanced to the\npoint that, in 2+1 flavour simulations, the cost of the strange quark is\nsignificant compared with the light quarks. This makes efficient filtering\nalgorithms for single flavour actions highly desirable, in particular when\nconsidering 1+1+1 flavour simulations for QED+QCD. Here we discuss methods for\nfiltering the RHMC algorithm that are implemented within BQCD, an open-source\nFortran program for Hybrid Monte Carlo simulations."
    },
    {
        "anchor": "Quark mass dependence of the vacuum electric conductivity induced by the\n  magnetic field in SU(2) lattice gluodynamics: We study the electric conductivity of the vacuum of quenched SU(2) lattice\ngauge theory induced by the magnetic field B as a function of the bare quark\nmass m. The conductivity grows as the quark mass decreases. Simplest power-like\nfit indicates that the conductivity behaves as B/sqrt(m). We discuss the\nimplications of this result for dilepton angular distributions in heavy ion\ncollisions.",
        "positive": "On the Landau-gauge adjoint quark propagator: Quarks in the adjoint representation have been a subject of study for both\nconceptual and practical purposes. Conceptually, their differences when it\ncomes to confining and chiral symmetry properties has long been suspected to\nhold important information on the relation of these two distinguished\nproperties of QCD-like gauge theories. Practically, they have been studied as\nboth a possibility to access finite density quark systems as well as candidate\ntheories for technicolor in beyond-the-standard-model settings. The most\nelementary object describing such particles is their propagator, though it\nbeing gauge-dependent. Its properties in the minimal Landau gauge are\ninvestigated here both in the quenched and unquenched case for a range of\nlattice parameters using the Wilson formulation for the gauge group SU(2). It\nis found that the propagator shows pronounced differences to the case of\nfundamental quarks, especially towards the chiral limit."
    },
    {
        "anchor": "The U(1)A anomaly in high temperature QCD with chiral fermions on the\n  lattice: The magnitude of the $U_A(1)$ symmetry breaking is expected to affect the\nnature of $N_f=2$ QCD chiral phase transition. The explicit breaking of chiral\nsymmetry due to realistic light quark mass is small, so it is important to use\nchiral fermions on the lattice to understand the effect of $U_A(1)$ near the\nchiral crossover temperature, $T_c$. We report our latest results for the\neigenvalue spectrum of 2+1 flavour QCD with dynamical Mobius domain wall\nfermions at finite temperature probed using the overlap operator on $32^3\\times\n8$ lattice. We check how sensitive the low-lying eigenvalues are to the\nsea-light quark mass. We also present a comparison with the earlier independent\nresults with domain wall fermions.",
        "positive": "Realization of Center Symmetry in Two Adjoint Flavor Large-N Yang-Mills: We report on the results of numerical simulations of $SU(N)$ lattice Yang\nMills with two flavors of (light) Wilson fermion in the adjoint representation.\nWe analytically and numerically address the question of center symmetry\nrealization on lattices with $\\Gamma$ sites in each direction in the large-$N$\nlimit. We show, by a weak coupling calculation that, for massless fermions,\ncenter symmetry realization is independent of $\\Gamma$, and is unbroken. Then,\nwe extend our result by conducting simulations at non zero mass and finite\ngauge coupling. Our results indicate that center symmetry is intact for a range\nof fermion mass in the vicinity of the critical line on lattices of volume\n$2^4$. This observation makes it possible to compute infinite volume physical\nobservables using small volume simulations in the limit $N\\to\\infty$, with\npossible applications to the determination of the conformal window in gauge\ntheories with adjoint fermions."
    },
    {
        "anchor": "An exploratory study of heavy domain wall fermions on the lattice: We report on an exploratory study of domain wall fermions (DWF) as a lattice\nregularisation for heavy quarks. Within the framework of quenched QCD with the\ntree-level improved Symanzik gauge action we identify the DWF parameters which\nminimise discretisation effects. We find the corresponding effective 4$d$\noverlap operator to be exponentially local, independent of the quark mass. We\ndetermine a maximum bare heavy quark mass of $am_h\\approx 0.4$, below which the\napproximate chiral symmetry and O(a)-improvement of DWF are sustained. This\nthreshold appears to be largely independent of the lattice spacing. Based on\nthese findings, we carried out a detailed scaling study for the heavy-strange\nmeson dispersion relation and decay constant on four ensembles with lattice\nspacings in the range $2.0-5.7\\,\\mathrm{GeV}$. We observe very mild $a^2$\nscaling towards the continuum limit. Our findings establish a sound basis for\nheavy DWF in dynamical simulations of lattice QCD with relevance to Standard\nModel phenomenology.",
        "positive": "Chiral Symmetry and BRST Symmetry Breaking, Quaternion Reality and the\n  Lattice Simulation: We discuss that the deviation of the Kugo-Ojima color confinement parameter\n$u(0)$ from -1 in the case of quenched lattice simulation and the consistency\nwith -1 in the case of full QCD simulation could be attributed to the boundary\ncondition defined by fermions inside the region of $r<1$fm. By using the domain\nwall fermion propagator in lattice simulation, we show that the chiral symmetry\nbreaking in the infrared can become manifest when one assumes that the\nleft-handed fermion on the left wall and the right-handed fermion on the right\nwall are correlated by a self-dual gauge field. The relation between the\ninfrared fixed point of the running coupling measured in lattice simulations,\nthe prediction of the BLM renormalization theory, the conformal field theory\nwith use of the t'Hooft anomaly matching condition in non-SUSY supersymmetric\ntheory and the quaternion real condition are discussed."
    },
    {
        "anchor": "A High-Statistics Lattice Calculation of $\u03bb_1$ and $\u03bb_2$ in\n  the $B$ meson: We present a high-statistics lattice calculation of the kinetic energy\n$-\\lambda_1/2 m_b$ of the heavy quark inside the $B$-meson and of the\nchromo-magnetic term $\\lambda_2$, related to the $B^*$--$B$ mass splitting,\nperformed in the HQET. Our results have been obtained from a numerical\nsimulation based on 600 gauge field configurations generated at $\\beta=6.0$, on\na lattice volume $24^3 \\times 40$ and using, for the meson correlators, the\nresults obtained with the SW-Clover $O(a)$ improved lattice action for the\nlight quarks. For the kinetic energy we found $-\\lambda_1=\\langle B \\vert \\bar\nh (i\\vec{D})^{2} h \\vert B \\rangle /(2 M_B )=-(0.09 \\pm 0.14)$~GeV$^2$, which\nis interesting for phenomenological applications. We also find $\\lambda_2= 0.07\n\\pm 0.01$ GeV$^2$, corresponding to $M^2_{B^*}-M^2_B= 4 \\lambda_2= 0.280 \\pm\n0.060 $ GeV$^2$, which is about one half of the experimental value. The origin\nof the discrepancy with the experimental number needs to be clarified.",
        "positive": "Complex Langevin method applied to the 2D $SU(2)$ Yang-Mills theory: The complex Langevin method in conjunction with the gauge cooling is applied\nto the two-dimensional lattice $SU(2)$ Yang-Mills theory that is analytically\nsolvable. We obtain strong numerical evidence that at large Langevin time the\nexpectation value of the plaquette variable converges, but to a wrong value\nwhen the complex phase of the gauge coupling is large."
    },
    {
        "anchor": "Many Masses on One Stroke: Economic Computation of Quark Propagators: The computational effort in the calculation of Wilson fermion quark\npropagators in Lattice Quantum Chromodynamics can be considerably reduced by\nexploiting the Wilson fermion matrix structure in inversion algorithms based on\nthe non-symmetric Lanczos process. We consider two such methods: QMR (quasi\nminimal residual) and BCG (biconjugate gradients). Based on the decomposition\n$M/\\kappa={\\bf 1}/\\kappa-D$ of the Wilson mass matrix, using QMR, one can carry\nout inversions on a {\\em whole} trajectory of masses simultaneously, merely at\nthe computational expense of a single propagator computation. In other words,\none has to compute the propagator corresponding to the lightest mass only,\nwhile all the heavier masses are given for free, at the price of extra storage.\nMoreover, the symmetry $\\gamma_5\\, M= M^{\\dagger}\\,\\gamma_5$ can be used to cut\nthe computational effort in QMR and BCG by a factor of two. We show that both\nmethods then become---in the critical regime of small quark\nmasses---competitive to BiCGStab and significantly better than the standard MR\nmethod, with optimal relaxation factor, and CG as applied to the normal\nequations.",
        "positive": "Nonextensive lattice gauge theories: algorithms and methods: High-energy phenomena presenting strong dynamical correlations, long-range\ninteractions and microscopic memory effects are well described by nonextensive\nversions of the canonical Boltzmann-Gibbs statistical mechanics. After a brief\ntheoretical review, we introduce a class of generalized heat-bath algorithms\nthat enable Monte Carlo lattice simulations of gauge fields on the nonextensive\nstatistical ensemble of Tsallis. The algorithmic performance is evaluated as a\nfunction of the Tsallis parameter q in equilibrium and nonequilibrium setups.\nThen, we revisit short-time dynamic techniques, which in contrast to usual\nsimulations in equilibrium present negligible finite-size effects and no\ncritical slowing down. As an application, we investigate the short-time\ncritical behaviour of the nonextensive hot Yang-Mills theory at q- values\nobtained from heavy-ion collision experiments. Our results imply that, when the\nequivalence of statistical ensembles is obeyed, the long-standing universality\narguments relating gauge theories and spin systems hold also for the\nnonextensive framework."
    },
    {
        "anchor": "Can rooted staggered fermions describe nonzero baryon density at low\n  temperatures?: Research on the QCD phase diagram with lattice field theory methods is\ndominated by the use of rooted staggered fermions, as they are the\ncomputationally cheapest discretization available. We show that rooted\nstaggered fermions at a nonzero baryochemical potential $\\mu_B$ predict a sharp\nrise in the baryon density at low temperatures and $\\mu_B \\gtrsim 3 m_\\pi/2$,\nwhere $m_\\pi$ is the Goldstone pion mass. We elucidate the nature of the\nnon-analyticity behind this sharp rise in the density by a comparison of\nreweighting results with a Taylor expansion of high order. While at first sight\nthis non-analytic behavior becomes apparent at the same position where the pion\ncondensation transition takes place in the phase-quenched theory, the nature of\nthe non-analyticity in the two theories appears to be quite different: While at\nnonzero isospin density the data are consistent with a genuine thermodynamic\n(branch-point) singularity, the results at nonzero baryon density point to an\nessential singularity at $\\mu_B=0$. The effect is absent for four flavors of\ndegenerate quarks, where rooting is not used. For the two-flavor case, we show\nnumerical evidence that the magnitude of the effect diminishes on finer\nlattices. We discuss the implications of this technical complication on future\nstudies of the QCD phase diagram.",
        "positive": "Systematic uncertainties in parton distribution functions from lattice\n  QCD simulations at the physical point: We present a detailed study of the helicity-dependent and\nhelicity-independent collinear parton distribution functions (PDFs) of the\nnucleon, using the quasi-PDF approach. The lattice QCD computation is performed\nemploying twisted mass fermions with a physical value of the light quark mass.\nWe give a systematic and in-depth account of the salient features entering in\nthe evaluation of quasi-PDFs and their relation to the light-cone PDFs. In\nparticular, we give details for the computation of the matrix elements,\nincluding the study of the various sources of systematic uncertainties, such as\nexcited states contamination. In addition, we discuss the non-perturbative\nrenormalization scheme used here and its systematics, effects of truncating the\nFourier transform and different matching prescriptions."
    },
    {
        "anchor": "A method to compute derivatives of functions of large complex matrices: A recently developed numerical method for the calculation of derivatives of\nfunctions of general complex matrices, which can also be combined with implicit\nmatrix function approximations such as Krylov-Ritz type algorithms, is\npresented. An important use case for the method in the context of lattice gauge\ntheory is the overlap Dirac operator at finite quark chemical potential.\nDerivatives of the lattice Dirac operator are necessary for the computation of\nconserved lattice currents or the fermionic force in Hybrid Monte-Carlo and\nLangevin simulations. To calculate the overlap Dirac operator at finite\nchemical potential the product of the sign function of a non-Hermitian matrix\nwith a vector has to be computed. For non-Hermitian matrices it is not possible\nto efficiently approximate the sign function with polynomials or rational\nfunctions. Implicit approximation algorithms, like Krylov-Ritz methods, that\ndepend on the source vector have to be used instead. Our method can also\nprovide derivatives of such implicit approximations. We show how a generalised\ndeflation prescription can be used to improve the performance of the method, if\nsome eigenvalues and eigenvectors of the matrix being differentiated are known.\nTo show that the method is efficient and well suited for practical calculations\nwe provide test results for the two-sided Lanczos approximation of the\nfinite-density overlap Dirac operator on SU(3) gauge field configurations on\nlattices with sizes up to $14 \\times 14^3$.",
        "positive": "Testing imaginary vs. real chemical potential in finite-temperature QCD: One suggestion for determining the properties of QCD at finite temperatures\nand densities is to carry out lattice simulations with an imaginary chemical\npotential whereby no sign problem arises, and to convert the results to real\nphysical observables only afterwards. We test the practical feasibility of such\nan approach for a particular class of physical observables, spatial correlation\nlengths in the quark-gluon plasma phase. Simulations with imaginary chemical\npotential followed by analytic continuation are compared with simulations with\nreal chemical potential, which are possible by using a dimensionally reduced\neffective action for hot QCD. We find that for imaginary chemical potential the\nsystem undergoes a phase transition at |mu/T| \\approx pi/3, and thus\nobservables are analytic only in a limited range. However, utilising this\nrange, relevant information can be obtained for the real chemical potential\ncase."
    },
    {
        "anchor": "Lattice QCD at finite density via a new canonical approach: We carry out a finite density calculation based on a canonical approach which\nis designed to address the overlap problem. Two degenerate flavor simulations\nare performed using Wilson gauge action and Wilson fermions on $4^4$ lattices,\nat temperatures close to the critical temperature $T_c\\approx 170\\MeV$ and\nlarge densities (5 to 20 times nuclear matter density). In this region, we find\nthat the algorithm works well. We compare our results with those from other\napproaches.",
        "positive": "A phase transition due to thick vortices in SU(2) lattice gauge theory: SU(2) lattice gauge theory is studied after eliminating thin monopoles and\nthe smallest thick monopoles. Kinematically this constraint allows thick vortex\nloops which produce long range Z(2) fluctuations. The thick vortex loops are\nidentified in a three dimensional simulation. A condensate of thick vortices\npersists even after the thin vortices have all disappeared. They decouple at a\nslightly lower temperature (higher $\\beta$) than the thin vortices and drive a\nZ(2) like phase transition."
    },
    {
        "anchor": "Gasser-Leutwyler coefficients: A progress report: Last year, we reported our first results on the determination of\nGasser-Leutwyler coefficients using partially quenched lattice QCD with three\nflavors of dynamical staggered quarks. We give an update on our progress in\ndetermining two of these coefficients, including an exhaustive effort to\nestimate all sources of systematic error. At this conference, we have heard\nabout algorithmic techniques to reduce staggered flavor symmetry breaking and a\nmethod to incorporate staggered flavor breaking into the partially quenched\nchiral Lagrangian. We comment on our plans to integrate these developments into\nour ongoing program.",
        "positive": "Finite volume QCD at fixed topological charge: In finite volume the partition function of QCD with a given $\\theta$ is a sum\nof different topological sectors with a weight primarily determined by the\ntopological susceptibility. If a physical observable is evaluated only in a\nfixed topological sector, the result deviates from the true expectation value\nby an amount proportional to the inverse space-time volume 1/V. Using the\nsaddle point expansion, we derive formulas to express the correction due to the\nfixed topological charge in terms of a 1/V expansion. Applying this formula, we\npropose a class of methods to determine the topological susceptibility in QCD\nfrom various correlation functions calculated in a fixed topological sector."
    },
    {
        "anchor": "Effects of Nonperturbative Improvement in Quenched Hadron Spectroscopy: We discuss a comparative analysis of unimproved and nonperturbatively\nimproved quenched hadron spectroscopy, on a set of 104 gauge configurations, at\nbeta=6.2. We also present here our results for meson decay constants, including\nthe constants f_D and f_Ds in the charm-quark region.",
        "positive": "Critical point of QCD at finite T and \u03bc, lattice results for physical\n  quark masses: A critical point (E) is expected in QCD on the temperature (T) versus\nbaryonic chemical potential (\\mu) plane. Using a recently proposed lattice\nmethod for \\mu \\neq 0 we study dynamical QCD with n_f=2+1 staggered quarks of\nphysical masses on L_t=4 lattices. Our result for the critical point is T_E=162\n\\pm 2 MeV and \\mu_E= 360 \\pm 40 MeV. For the critical temperature at \\mu=0 we\nobtained T_c=164 \\pm 2 MeV. This work extends our previous study [Z. Fodor and\nS.D.Katz, JHEP 0203 (2002) 014] by two means. It decreases the light quark\nmasses (m_{u,d}) by a factor of three down to their physical values.\nFurthermore, in order to approach the thermodynamical limit we increase our\nlargest volume by a factor of three. As expected, decreasing m_{u,d} decreased\n\\mu_E. Note, that the continuum extrapolation is still missing"
    },
    {
        "anchor": "The Theory of Dynamical Random Surfaces with Extrinsic Curvature: We analyze numerically the critical properties of a two-dimensional\ndiscretized random surface with extrinsic curvature embedded in a\nthree-dimensional space. The use of the toroidal topology enables us to enforce\nthe non-zero external extension without the necessity of defining a boundary\nand allows us to measure directly the string tension. We show that a phase\ntransition from the crumpled phase to the smooth phase observed earlier for a\nspherical topology appears also for a toroidal surface for the same finite\nvalue of the coupling constant of the extrinsic curvature term. The phase\ntransition is characterized by the vanishing of the string tension. We discuss\nthe possible non-trivial continuum limit of the theory, when approaching the\ncritical point. Numerically we find a value of the critical exponent $\\n$ to be\nbetween .38 and .42. The specific heat, related to the extrinsic curvature term\nseems not to diverge (or diverge slower than logarithmically) at the critical\npoint.",
        "positive": "Nucleon distribution amplitudes from lattice QCD: We calculate low moments of the leading-twist and next-to-leading twist\nnucleon distribution amplitudes on the lattice using two flavors of clover\nfermions. The results are presented in the MSbar scheme at a scale of 2 GeV and\ncan be immediately applied in phenomenological studies. We find that the\ndeviation of the leading-twist nucleon distribution amplitude from its\nasymptotic form is less pronounced than sometimes claimed in the literature."
    },
    {
        "anchor": "Toward the Chiral Limit of QCD: Quenched and Dynamical Domain Wall\n  Fermions: A serious difficulty in conventional lattice field theory calculations is the\ncoupling between the chiral and continuum limits. With both staggered and\nWilson fermions, the chiral limit cannot be realized without first taking the\nlimit of vanishing lattice spacing. In this talk, we report on extensive\nstudies of the domain wall formulation of lattice fermions, which avoids this\ndifficulty at the expense of requiring that fermion propagators be computed in\nfive dimensions. A variety of results will be described for quenched and\ndynamical simulations at both zero and finite temperature. Conclusions about\nthe benefits of this new method and some new physical results will be\npresented. These results were obtained on the QCDSP machines recently put into\noperation at Columbia and the RIKEN Brookhaven Research Center.",
        "positive": "Recent developments at finite density on the lattice: Some recent developments to handle the numerical sign problem in QCD and\nrelated theories at nonzero density are reviewed. In this contribution I focus\non changing the integration order to soften the severity of the sign problem,\nthe density of states, and the extension into the complex plane (complex\nLangevin dynamics and Lefshetz thimbles)."
    },
    {
        "anchor": "Non-$\u03b3_{5}$hermiticity minimal doubling fermion: We formulate new two dimensional fermions breaking $\\gamma_{5}$hermiticity,\nbased on the minimal doubling fermion. We investigate their properties: (I)\nSymmetries, (II) eigenvalue distributions, and (III)the number of poles. As a\nsimple application of the fermions, the Gross-Neveu model in two dimensions is\nstudied using the fermion. We obtain the parity broken phase diagram called\nAoki phase and the chiral broken phase diagram of the model with an imaginary\nchemical potential.",
        "positive": "High precision Monte Carlo simulations of interfaces in the\n  three-dimensional Ising model: a comparison with the Nambu-Goto effective\n  string model: Motivated by the recent progress in the effective string description of the\ninterquark potential in lattice gauge theory, we study interfaces with periodic\nboundary conditions in the three-dimensional Ising model. Our Monte Carlo\nresults for the associated free energy are compared with the next-to-leading\norder (NLO) approximation of the Nambu-Goto string model. We find clear\nevidence for the validity of the effective string model at the level of the NLO\ntruncation."
    },
    {
        "anchor": "Possible lattice approach to B to D pi (K) matrix elements: We present an approach for computing the real parts of the nonleptonic B to\nDP and B to D-bar P (P=K,pi) decay amplitudes by using lattice QCD methods.\nWhile it remains very challenging to calculate the imaginary parts of these\nmatrix elements on the lattice, we stress that their real parts play a\nsignificant role in extracting the angle gamma in the b-d unitarity triangle of\nthe CKM matrix. The real part on its own gives a lower bound to the absolute\nmagnitude of the amplitude which is in itself an important constraint for\ndetermining gamma. Also the relevant phase can be obtained by using B-decays in\nconjunction with relevant charm decay data. Direct four-point function\ncalculations on the lattice, while computationally demanding, does yield the\nreal part as that is not impeded by the Maiani-Testa theorem. As an\napproximation, we argue that the chiral expansion of these decays is valid in a\nframework similar to that of hard-pion chiral perturbation theory. In addition\nto constructing the leading-order operators, we also discuss the features of\nthe next-to-leading order chiral expansion. These include the contributions\nfrom the resonance states, as well as the generic forms of the chiral\nlogarithms.",
        "positive": "Hunting the static energy renormalon: We employ Numerical Stochastic Perturbation Theory (NSPT) together with\ntwisted boundary conditions (TBC) to search for the leading renormalon in the\nperturbative expansion of the static energy. This renormalon is expected to\nemerge four times faster than the one for the gluon conden- sate in the\nplaquette. We extract the static energy from Polyakov loop calculations up to\n12 loops and present preliminary results, indicating a significant step towards\nconfirming the theoretical expectation."
    },
    {
        "anchor": "Confined gluon from Minkowski space continuation of PT-BFM SDE solution: Recent lattice studies exhibit infrared finite effective QCD charges.\nCorresponding gluon propagator in Landau gauge is finite and nonzero,\nsuggesting a mechanism of dynamical gluon mass generation is in the operation.\nIn this paper, the analytical continuation of the Euclidean (spacelike) Pinch\nTechnique-Background Field Method (PT-BFM) solution of Schwinger-Dyson equation\nfor gluon propagator to the timelike region of $q^2$ is found. We found the\ncontinuation numerically showing good agreement with a generalized Lehman\nrepresentation for small Schwinger coupling. The associate non-positive\nspectral function has an unexpected behavior. Albeit infrared Euclidean space\nsolution naively suggests like single scale \"massive\" propagator, the obtained\nspectrum of gluon propagator does not correspond to the delta function at\nsingle scale $q=m$, instead more possible singularities are generated. The\npattern depends on the details of assumed Schwinger mechanism: for stronger\ncoupling there are few maxima and minima which appear at the scale $\\Lambda$,\nwhile for perturbatively small Schwinger coupling the spectral function shows\nup two narrow peaks: particle and ghost excitation, which have mutually\nopposite signs.",
        "positive": "Non-perturbative scale evolution of four-fermion operators in\n  two-flavour QCD: We apply finite-size recursion techniques based on the Schrodinger functional\nformalism to determine the renormalization group running of four-fermion\noperators which appear in the Delta S=2 effective weak Hamiltonian of the\nStandard Model. Our calculations are done using O(a) improved Wilson fermions\nwith N_f=2 dynamical flavours. Preliminary results are presented for the\nfour-fermion operator which determines the B_K parameter in tmQCD."
    },
    {
        "anchor": "The parity-odd structure function of nucleon from the Compton amplitude: The dominant contribution to the theoretical uncertainty in the extracted\nweak parameters of the Standard Model comes from the hadronic uncertainties in\nthe electroweak boxes, i.e. $\\gamma-W^\\pm/Z$ exchange diagrams. A dispersive\nanalysis relates the box diagrams to the parity-odd structure function, $F_3$,\nfor which the experimental data either do not exist or belong to a separate\nisospin channel. Therefore a first-principles calculation of $F_3$ is highly\ndesirable. In this contribution, we report on the QCDSF/UKQCD Collaboration's\nprogress in calculating the moments of the $F_3^{\\gamma Z}$ structure function\nfrom the forward Compton amplitude at the SU(3) symmetric point.",
        "positive": "Thermal Abelian monopoles as selfdual dyons: The properties of the thermal Abelian monopoles are studied in the\ndeconfinement phase of the SU(2) gluodynamics. To remove effects of Gribov\ncopies the simulated annealing algorithm is applied to fix the maximally\nAbelian gauge. To study monopole profile we complete the first computations of\nexcess of the nonabelian action density as a function of the distance from the\ncenter of the thermal Abelian monopole. We have found that starting from the\ndistances $\\approx$ 2 lattice spacings the chromoelectric and chromomagnetic\naction densities created by monopole are equal to each other, from what we draw\na conclusion that monopole is a dyon. Furthermore, we find that the\nchromoelectric and chromomagnetic fields decrease exponentially with increasing\ndistance. These findings were confirmed for different temperatures in the range\n$T/T_c \\in (1.5, 4.8)$."
    },
    {
        "anchor": "Gluon Propagators in $2+1$ Lattice QCD with Nonzero Isospin Chemical\n  Potential: The static longitudinal and transverse gluon propagators in the Landau gauge\nare studied in $2+1$ lattice QCD with nonzero isospin chemical potential\n$\\mu_I$. Parameterization of the momentum dependence of the propagators is\nprovided for all values of the chemical potential under study. We find that the\nlongitudinal propagator is infrared suppressed at nonzero $\\mu_I$ with\nsuppression increasing with increasing $\\mu_I$. It is found, respectively, that\nthe electric screening mass is increasing with increasing $\\mu_I$.\nAdditionally, we analyze the difference between two propagators as a function\nof the momentum and thus compare interactions in chromoelectric and\nchromomagnetic sectors.",
        "positive": "High Spin Glueballs from the Lattice: We discuss the principles underlying higher spin glueball calculations on the\nlattice. For that purpose, we develop numerical techniques to rotate Wilson\nloops by arbitrary angles in lattice gauge theories close to the continuum. As\na first application, we compute the glueball spectrum of the SU(2) gauge theory\nin 2+1 dimensions for both parities and for spins ranging from 0 up to 4\ninclusive. We measure glueball angular wave functions directly, decomposing\nthem in Fourier modes and extrapolating the Fourier coefficients to the\ncontinuum. This allows a reliable labelling of the continuum states and gives\ninsight into the way rotation symmetry is recovered. As one of our results, we\ndemonstrate that the D=2+1 SU(2) glueball conventionally labelled as J^P = 0^-\nis in fact 4^- and that the lightest ``J=1'' state has, in fact, spin 3."
    },
    {
        "anchor": "Non-perturbative renormalization of quark mass in Nf=2+1 QCD with the\n  Schroedinger functional scheme: We present an evaluation of the quark mass renormalization factor for Nf=2+1\nQCD. The Schroedinger functional scheme is employed as the intermediate scheme\nto carry out non-perturbative running from the low energy region, where\nrenormalization of bare mass is performed on the lattice, to deep in the high\nenergy perturbative region, where the conversion to the renormalization group\ninvariant mass or the MS-bar scheme is safely carried out. For numerical\nsimulations we adopted the Iwasaki gauge action and non-perturbatively improved\nWilson fermion action with the clover term. Seven renormalization scales are\nused to cover from low to high energy regions and three lattice spacings to\ntake the continuum limit at each scale. The regularization independent step\nscaling function of the quark mass for the Nf=2+1 QCD is obtained in the\ncontinuum limit. Renormalization factors for the pseudo scalar density and the\naxial vector current are also evaluated for the same action and the bare\ncouplings as two recent large scale Nf=2+1 simulations; previous work of the\nCP-PACS/JLQCD collaboration, which covered the up-down quark mass range heavier\nthan $m_\\pi\\sim 500$ MeV and that of PACS-CS collaboration for much lighter\nquark masses down to $m_\\pi=155$ MeV. The quark mass renormalization factor is\nused to renormalize bare PCAC masses in these simulations.",
        "positive": "Cluster simulation of two-dimensional relativistic fermions: The (discrete) Gross-Neveu model is studied in a lattice realization with an\nN-component Majorana Wilson fermion field. It has an internal O(N) symmetry in\naddition to the euclidean lattice symmetries. The discrete chiral symmetry for\nvanishing mass is expected to emerge in the continuum limit only. The lattice\ntheory is first recast in terms of two-valued bosonic link variables (dimers).\nIn this representation, which coincides with the loop representation obtained\nearlier by Gattringer with the help of eight-vertex-models, the Boltzmann\nweight is essentially positive. While standard local updates are possible in\nthis form we construct a further exact transformation where we generate dimer\nconfigurations as Peierls contours of an Ising model with a local action\nresiding on plaquettes. For this model a Swendsen-Wang type cluster algorithm\nis constructed. At vanishing coupling it is numerically demonstrated to almost\ncompletely eliminate critical slowing down. Although further tests are\nrequired, an avenue to numerical studies of the Gross-Neveu model with\nunprecedented precision seems open."
    },
    {
        "anchor": "Hadron spectroscopy from canonical partition functions: A spectroscopic method for staggered fermions based on thermodynamical\nconsiderations is proposed. The canonical partition functions corresponding to\nthe different quark number sectors are expressed in the low temperature limit\nas polynomials of the eigenvalues of the reduced fermion matrix. Taking the\nzero temperature limit yields the masses of the lowest states. The method is\nsuccessfully applied to the Goldstone pion and both dynamical and quenched\nresults are presented showing good agreement with that of standard\nspectroscopy. Though in principle the method can be used to obtain the baryon\nand dibaryon masses, due to their high computational costs such calculations\nare practically unreachable.",
        "positive": "Lattice Gauge Theory Simulations at Nonzero Chemical Potential in the\n  Chiral Limit: We present a method of simulating lattice QCD at nonzero chemical potential\nin the chiral limit. By adding a weak four-fermi interaction to the standard\nstaggered fermion SU(3) QCD action, we produce an algorithm in which the limit\nof massless fermions is well-behaved and physical. Using configurations at zero\nchemical potential, and an exact fugacity expansion of the fermion determinant,\nwe can simulate QCD at nonzero chemical potential and evade the notorious\nproblem of the complex action. Small lattice simulations give physical results:\nAt strong gauge coupling the critical chemical potential \\mu_c agrees with\ntheoretical expectations and at weak gauge coupling \\mu_c is nonzero in the low\ntemperature confined phase of QCD and jumps to zero in the high temperature\nquark-gluon plasma phase. In all these simulations the quarks are exactly\nmassless and there is a Goldstone pion."
    },
    {
        "anchor": "NRQCD results on the MILC extra coarse ensemble: We present preliminary results using NRQCD to describe heavy quarks on the\nMILC 2+1 flavour dynamical extra coarse ensemble. We calculate the spectra of\nlow lying states in bottomonium to complement earlier results on the finer MILC\nensembles. We then exploit the coarseness of the lattices to calculate charm\npropagators using NRQCD. These are used to examine the charmonium spectrum and\nto calclate the mass of the $B_c$ using NRQCD. Finally we look breifly at the\n$B_d$ and $B_s$ systems using the imporoved staggered formalism to describe the\nlight valence quarks.",
        "positive": "$B_c$ spectroscopy using highly improved staggered quarks: We report on a calculation of $B_c$ ground state and radial excitation\nenergies, obtained from heavy-charm highly improved staggered quark (HISQ)\ncorrelators computed on MILC gauge ensembles, with lattice spacings down to\n$a=0.044$ fm. Using HISQ valence quarks on progressively finer lattices allows\nus to simulate up to the $b$-quark mass. In particular we focus on the\n$B_c(2S)$ energy, which we compare with O(\\alpha_s)-improved non-relativistic\nQCD results computed on the same ensembles and recent experimental results from\nATLAS."
    },
    {
        "anchor": "Describing gluons at zero and finite temperature: Any description of gluons requires a well-defined gauge. This is complicated\nnon-perturbatively by Gribov copies. A possible method-independent gauge\ndefinition to resolve this problem is presented and afterwards used to study\nthe properties of gluons at any temperature. It is found that only\nchromo-electric properties reflect the phase transition. From these the\ngauge-invariant phase transition temperature is determined for SU(2) and SU(3)\nYang-Mills theory independently.",
        "positive": "Complex spacing ratios of the non-Hermitian Dirac operator in\n  universality classes AI$^\\dagger$ and AII$^\\dagger$: We consider non-Hermitian Dirac operators in QCD-like theories coupled to a\nchiral U(1) potential or an imaginary chiral chemical potential. We show that\nin the continuum they fall into the recently discovered universality classes\nAI$^\\dagger$ or AII$^\\dagger$ of random matrix theory if the fermions transform\nin pseudoreal or real representations of the gauge group, respectively. For\nstaggered fermions on the lattice this correspondence is reversed. We verify\nour predictions by computing spacing ratios of complex eigenvalues, whose\ndistribution is universal without the need for unfolding."
    },
    {
        "anchor": "The Nonperturbative Broken Phase Sphaleron Rate: I present a technique for measuring the broken phase sphaleron rate\nnonperturbatively. There are three parts to the calculation: determination of\nthe probability distribution of Chern-Simons number NCS; measurement of <|\nd\\NCS/dt |> at NCS=1/2, the mean rate of change of NCS at the barrier; and\nmeasurement of the ``dynamical prefactor,'' the fraction of barrier crossings\nwhich result in a permanent integer change in NCS.",
        "positive": "Study of thermal monopoles in lattice QCD: The properties of the thermal Abelian color-magnetic monopoles in the\nmaximally Abelian gauge are studied in the vicinity of the\nconfinement-deconfinement phase transition in the lattice $SU(3)$ gluodynamics\nand lattice QCD. We compute the density and interaction parameters of the\nthermal monopoles. We find that the density of the thermal monopoles $\\rho(T)$\njumps up near the transition temperature $T_c$. Additionally we present new\nresults on the percolation transition in $SU(3)$ gluodynamics which is known to\ncoincide in gluodynamics with the confinement-deconfinement phase transition."
    },
    {
        "anchor": "Screening masses in the SU(3) pure gauge theory and universality: We determine from Polyakov loop correlators the screening masses in the\ndeconfined phase of the (3+1)d SU(3) pure gauge theory at finite temperature\nnear the transition, for two different channels of angular momentum and parity.\nTheir ratio is compared with that of the massive excitations with the same\nquantum numbers in the 3d 3-state Potts model in the broken phase near the\ntransition point at zero magnetic field. Moreover we study the inverse decay\nlength of the correlation between the real parts and between the imaginary\nparts of the Polyakov loop and compare the results with expectations from\nperturbation theory and mean-field Polyakov loop models.",
        "positive": "Finite-volume two-pion energies and scattering in the quenched\n  approximation: We investigate how L\\\"uscher's relation between the finite-volume energy of\ntwo pions at rest and pion scattering lengths has to be modified in quenched\nQCD. We find that this relation changes drastically, and in particular, that\n``enhanced finite-volume corrections\" of order $L^0=1$ and $L^{-2}$ occur at\none loop ($L$ is the linear size of the box), due to the special properties of\nthe $\\eta'$ in the quenched approximation. We define quenched pion scattering\nlengths, and show that they are linearly divergent in the chiral limit. We\nestimate the size of these various effects in some numerical examples, and find\nthat they can be substantial."
    },
    {
        "anchor": "Detailed study of quark-antiquark flux tubes and flux tube recombination: In this work we compute the color fields in the mediator plane between a\nstatic quark and a static antiquark using quenched lattice QCD. In special, we\nsee the effect of the quark-antiquark distance on the flux tube. To obtain this\nresults an improved multihit technique is developed and an extend smearing\ntechnique is used. Then, we also discuss the flux-tubes in a system composed of\ntwo quarks and two antiquarks. The ground and first excited states fields are\nstudied for different dispositions of the system.",
        "positive": "Higher order cumulants of electric charge and strangeness fluctuations\n  on the crossover line: We present lattice QCD calculations of higher order cumulants of electric\ncharge distributions for small baryon chemical potentials $\\mu_B$ by using up\nto NNNLO Taylor expansions. Ratios of these cumulants are evaluated on the\npseudo-critical line, $T_{pc}(\\mu_B)$, of the chiral transition and compared to\ncorresponding measurements in heavy ion collision experiments by the STAR and\nPHENIX Collaborations. We demonstrate that these comparisons give strong\nconstraints on freeze-out parameters. Furthermore, we use strangeness\nfluctuation observables to compute the ratio $\\mu_S/\\mu_B$ on the crossover\nline and compare it to $\\mu_S/\\mu_B$ at freeze-out stemming from fits to\nstrange baryon yields measured by the STAR Collaboration."
    },
    {
        "anchor": "Gauge-Invariant Formalism with a Dirac-mode Expansion for Confinement\n  and Chiral Symmetry Breaking: Using the eigen-mode of the QCD Dirac operator $\\Slash D=\\gamma^\\mu D^\\mu$,\nwe develop a manifestly gauge-covariant expansion and projection of the QCD\noperators such as the Wilson loop and the Polyakov loop. With this method, we\nperform a direct analysis of the correlation between confinement and chiral\nsymmetry breaking in lattice QCD Monte Carlo calculation on $6^4$ at\n$\\beta$=5.6. Even after removing the low-lying Dirac modes, which are\nresponsible to chiral symmetry breaking, we find that the Wilson loop obeys the\narea law, and the slope parameter corresponding to the string tension or the\nconfinement force is almost unchanged. We find also that the Polyakov loop\nremains to be almost zero even without the low-lying Dirac modes, which\nindicates the $Z_3$-unbroken confinement phase. These results indicate that\none-to-one correspondence does not hold for between confinement and chiral\nsymmetry breaking in QCD.",
        "positive": "Chirality tubes along monopole trajectories: We classify the lattice by elementary 3-cubes which are associated to dual\nlinks occupied by, or free of monopoles. We then compute the quark condensate,\nthe quark charge and the chiral density on those cubes. By looking at\ndistributions we demonstrate that monopole trajectories carry considerably more\nchirality with respect to the free vacuum."
    },
    {
        "anchor": "Relating Chiral Perturbation Theory and QCD Simulations with Overlap\n  Hypercube Fermions: We present simulation results for lattice QCD with light pions. For the quark\nfields we apply chirally symmetric lattice Dirac operators, in particular the\noverlap hypercube operator, along with the standard overlap operator for\ncomparison. This allows us to simulate at very low pion masses. The results are\nrelated to Random Matrix Theory and to Chiral Perturbation Theory in order to\nextract information about the pion decay constant, the scalar condensate and\nthe topological susceptibility.",
        "positive": "The fermion bag approach to lattice field theories: We propose a new approach to the fermion sign problem in systems where there\nis a coupling $U$ such that when it is infinite the fermions are paired into\nbosons and there is no fermion permutation sign to worry about. We argue that\nas $U$ becomes finite fermions are liberated but are naturally confined to\nregions which we refer to as {\\em fermion bags}. The fermion sign problem is\nthen confined to these bags and may be solved using the determinantal trick. In\nthe parameter regime where the fermion bags are small and their typical size\ndoes not grow with the system size, construction of Monte Carlo methods that\nare far more efficient than conventional algorithms should be possible. In the\nregion where the fermion bags grow with system size, the fermion bag approach\ncontinues to provide an alternative approach to the problem but may lose its\nmain advantage in terms of efficiency. The fermion bag approach also provides\nnew insights and solutions to sign problems. A natural solution to the \"silver\nblaze problem\" also emerges. Using the three dimensional massless lattice\nThirring model as an example we introduce the fermion bag approach and\ndemonstrate some of these features. We compute the critical exponents at the\nquantum phase transition and find $\\nu=0.87(2)$ and $\\eta=0.62(2)$."
    },
    {
        "anchor": "Twist-two matrix elements at finite and infinite volume: We present one-loop results for the forward twist-two matrix elements\nrelevant to the unpolarised, helicity and transversity baryon structure\nfunctions, in partially-quenched (N_f=2 and N_f=2+1) heavy baryon chiral\nperturbation theory. The full-QCD limit can be straightforwardly obtained from\nthese results and we also consider SU(2|2) quenched QCD. Our calculations are\nperformed in finite volume as well as in infinite volume. We discuss features\nof lattice simulations and investigate finite volume effects in detail. We find\nthat volume effects are not negligible, typically around 5--10% in current\npartially-quenched and full QCD calculations, and are possibly larger in\nquenched QCD. Extensions to the off-forward matrix elements and potential\ndifficulties that occur there are also discussed.",
        "positive": "Lattice baryons in the 1/N expansion: Results are presented for hadron spectroscopy with gauge groups SU(N) with\nN=3, 5, 7. Calculations use the quenched approximation. Lattice spacings are\nmatched using the static potential. Meson spectra show independence on N and\nvacuum-to-hadron matrix elements scale as the square root of N. The baryon\nspectrum shows the excitation levels of a rigid rotor."
    },
    {
        "anchor": "Novel applications of Lattice QCD: Parton distribution functions, proton\n  charge radius and neutron electric dipole moment: We briefly discuss the current status of lattice QCD simulations and review\nselective results on nucleon observables focusing on recent developments in the\nlattice QCD evaluation of the nucleon form factors and radii, parton\ndistribution functions and their moments, and the neutron electric dipole\nmoment. Nucleon charges and moments of parton distribution functions are\npresented using simulations generated at physical values of the quark masses,\nwhile exploratory studies are performed for the parton distribution functions\nand the neutron electric dipole moment at heavier than physical value of the\npion mass.",
        "positive": "Determination of crossing-symmetric $\u03c0\u03c0$ scattering amplitudes and\n  the quark mass evolution of the $\u03c3$ constrained by lattice QCD: Lattice QCD spectra can be used to constrain partial-wave scattering\namplitudes that, while satisfying unitarity, do not have to respect crossing\nsymmetry and analyticity. This becomes a particular problem when extrapolated\nfar from real energies, e.g. in the case of broad resonances like the $\\sigma$,\nleading to large systematic uncertainties in the pole position. In this\nmanuscript, we will show how dispersion relations can implement the additional\nconstraints, using as input lattice--determined $\\pi\\pi$ partial-wave\nscattering amplitudes with isospin--0,1,2. We will show that only certain\ncombinations of amplitude parameterizations satisfy all constraints, and that\nwhen we restrict to these, the $\\sigma$ pole position is determined with\nminimal systematic uncertainty. The evolution of the now well-constrained\n$\\sigma$ pole with varying light quark mass is presented, showing how it\ntransitions from a bound-state to a broad resonance."
    },
    {
        "anchor": "Evidence for a first order transition in a plaquette 3d Ising-like\n  action: We investigate a 3d Ising action which corresponds to a a class of models\ndefined by Savvidy and Wegner, originally intended as discrete versions of\nstring theories on cubic lattices. These models have vanishing bare surface\ntension and the couplings are tuned in such a way that the action depends only\non the angles of the discrete surface, i.e. on the way the surface is embedded\nin ${\\bf Z}^3$. Hence the name gonihedric by which they are known. We show that\nthe model displays a rather clear first order phase transition in the limit\nwhere self-avoidance is neglected and the action becomes a plaquette one. This\ntransition persists for small values of the self avoidance coupling, but it\nturns to second order when this latter parameter is further increased. These\nresults exclude the use of this type of action as models of gonihedric random\nsurfaces, at least in the limit where self avoidance is neglected.",
        "positive": "The role of Lattice QCD in flavor physics: Understanding flavor physics is one of the most important tasks of particle\nphysics today, which is motivating an extraordinary experimental and\ntheoretical investigational effort. Important progress in this field has\nalready been achieved in the last few years, with Lattice QCD calculations\nplaying an essential role in this effort. I will describe some lattice\ncontributions to the studies of flavor physics by focusing particularly on the\ndetermination of the CKM matrix and on the study of CP violation in the\nStandard Model."
    },
    {
        "anchor": "Noncommutativity Approach to Supersymmetry on the Lattice: SUSY Quantum\n  Mechanics and an Inconsistency: It is argued that the noncommutativity approach to fully supersymmetric field\ntheories on the lattice suffers from an inconsistency. Supersymmetric quantum\nmechanics is worked out in this formalism and the inconsistency is shown both\nin general and explicitly for that system, as well as for the Abelian super BF\nmodel.",
        "positive": "Gauge-equivariant pooling layers for preconditioners in lattice QCD: We demonstrate that gauge-equivariant pooling and unpooling layers can\nperform as well as traditional restriction and prolongation layers in multigrid\npreconditioner models for lattice QCD. These layers introduce a gauge degree of\nfreedom on the coarse grid, allowing for the use of explicitly\ngauge-equivariant layers on the coarse grid. We investigate the construction of\ncoarse-grid gauge fields and study their efficiency in the preconditioner\nmodel. We show that a combined multigrid neural network using a Galerkin\nconstruction for the coarse-grid gauge field eliminates critical slowing down."
    },
    {
        "anchor": "Baryon bag simulation of QCD in the strong coupling limit: We explore the possibility of a simulation of strong coupling QCD in terms of\nso-called baryon bags. In this form the known representation in terms of\nmonomers, dimers and baryon loops is reorganized such that the baryon\ncontributions are collected in space time domains referred to as baryon bags.\nWithin the bags three quarks propagate coherently as a baryon that is described\nby a free fermion, whereas the rest of the lattice is solely filled with\ninteracting meson terms, i.e., quark and diquark monomers and dimers. We\nperform a simulation directly in the baryon bag language using a newly\ndeveloped worm update and show first results in two dimensions.",
        "positive": "Impact of large cutoff-effects on algorithms for improved Wilson\n  fermions: As a feasibility study for a scaling test we investigate the behavior of\nalgorithms for dynamical fermions in the N_f=2 Schroedinger functional at an\nintermediate volume of 1 fm^4. Simulations were performed using HMC with two\npseudo-fermions and PHMC at lattice spacings of approximately 0.1 and 0.07 fm.\nWe show that some algorithmic problems are due to large cutoff-effects in the\nspectrum of the improved Wilson-Dirac operator and disappear at the smaller\nlattice spacing. The problems discussed here are not expected to be specific to\nthe Schroedinger functional."
    },
    {
        "anchor": "Overcoming strong metastabilities with the LLR method: In previous work, it has been shown that the recently proposed LLR method is\nvery efficient at overcoming strong metastabilities that arise near first-order\nphase transition points. Here we present a systematic study of the performance\nof the algorithm near (pseudo-)critical points for $q$-state Potts models with\n$q$ as large as 20, in two and three dimensions. In particular, we shall focus\nour study on the ergodicity of the replica exchange step and the underlying\nphysical mechanism. When compared with both analytical and numerical results\npresent in the literature, our determinations of thermodynamic observables\n(including the order-disorder interface tension at criticality) show an\nimpressive degree of relative accuracy (up to $2.5 \\times 10^{-6}$), which\nconfirms the reliability and the efficiency of the proposed approach.",
        "positive": "Logarithmic corrections to O(a^2) lattice artifacts: We compute logarithmic corrections to the O(a^2) lattice artifacts for a\nclass of lattice actions for the non-linear O(n) sigma-model in two dimensions.\nThe generic leading artifacts are of the form $a^2[\\ln(a^2)]^{(n/(n-2))}$. We\nalso compute the next-to-leading corrections and show that for the case n=3 the\nresulting expressions describe well the lattice artifacts in the step scaling\nfunction, which are in a large range of the cutoff apparently of the form O(a).\nAn analogous computation should, if technically possible, accompany any\nprecision measurements in lattice QCD."
    },
    {
        "anchor": "Investigating the Two-Dimensional Generalized XY Model using Tensor\n  Networks: The critical behavior of the two-dimensional XY model has been explored in\nthe literature using various methods. They include the high-temperature\nexpansion (HTE) method, Monte Carlo (MC) approach, strong coupling expansion\nmethod, and tensor network (TN) methods. This model undergoes a\nBerezinskii-Kosterlitz-Thouless (BKT) type of phase transition. This model can\nbe modified by adding spin-nematic interaction terms with a period to give rise\nto the generalized XY model. The modified model contains excitations of integer\nand half-integer vortices. These vortices govern the critical behavior of the\ntheory and produce rich physics. With the help of tensor networks, we\ninvestigate the transition behavior between the integer vortex binding and\nhalf-integer vortex binding phases of the model and how this transition line\nmerges into two BKT transition lines.",
        "positive": "A precise determination of the HVP contribution to the muon anomalous\n  magnetic moment from lattice QCD: In this talk I present the current status of a precise first-principles\ncalculation of the quark connected, quark disconnected, and leading QED and\nstrong isospin-breaking contributions to the leading-order hadronic vacuum\npolarization by the RBC and UKQCD collaborations. The lattice data is also\ncombined with experimental $e^+ e^-$ scattering data, consistency between the\ntwo datasets is checked, and a combined result with smaller error than the\nlattice data and $e^+ e^-$ scattering data individually is presented."
    },
    {
        "anchor": "Quenched lattice calculation of the B --> D l nu decay rate: We calculate, in the continuum limit of quenched lattice QCD, the form factor\nthat enters in the decay rate of the semileptonic decay B --> D l nu. Making\nuse of the step scaling method (SSM), previously introduced to handle two scale\nproblems in lattice QCD, and of flavour twisted boundary conditions we extract\nG(w) at finite momentum transfer and at the physical values of the heavy quark\nmasses. Our results can be used in order to extract the CKM matrix element Vcb\nby the experimental decay rate without model dependent extrapolations.",
        "positive": "Lattice QCD and chiral mesons: The standard QCD action is improved by the addition of irrelevant operators\nbuilt with chiral composites. An effective Lagrangian is derived in terms of\nauxiliary fields, which has the form of the phenomenological chiral\nLagrangians. Our improved QCD action appears promising for numerical\nsimulations as the pion physics is explicitely accounted for by the auxiliary\nfields."
    },
    {
        "anchor": "SU(3) Deconfining Phase Transition in a Box with Cold Boundaries: Deconfined regions created in heavy ion collisions are bordered by the\nconfined phase. We discuss boundary conditions (BCs) to model a cold exterior.\nMonte Carlo simulations of pure SU(3) lattice gauge theory with thus inspired\nBCs show scaling. Corrections to usual results survive in the finite volume\ncontinuum limit and we estimate them in a range from L=5-10 fermi as function\nof the volume size $L^3$. In magnitude these corrections are comparable to\nthose obtained by including quarks.",
        "positive": "An Observation of Autocorrelation of Wilson Loops on Lattice: An observation of autocorrelation of Wilson loops on lattice is presented,\nespecially for the small seperation in Markov chain. We give a possible\nexplanation for such behavior. We also present the dependence of\nautocorrelation behavior on the chosen operators in this paper."
    },
    {
        "anchor": "Dual Higgs Mechanism based on the Dual Gauge Formalism in the Lattice\n  QCD: We study the dual Higgs mechanism induced by monopole condensation based on\nthe dual gauge formalism in the maximally abelian (MA) gauge in the lattice\nQCD. To examine ``monopole condensation'' in QCD, we study the monopole part or\nthe monopole-current system appearing in the MA gauge by extracting the dual\ngluon field $B_\\mu$. First, we investigate the inter-monopole potential using\nthe dual Wilson loop in the lattice QCD simulation. In the monopole part in the\nMA gauge, the inter-monopole potential is found to be flat, and can be fitted\nas the Yukawa potential in the infrared region. From more detailed analysis of\nthe inter-monopole potential considering the monopole size, we estimate the\neffective dual-gluon mass $m_B \\simeq 0.5$GeV and the effective monopole size\n$R_{^{_{\\rm M}}} \\simeq 0.2$fm. Second, we study the dual gluon propagator\n$G^D_{\\mu\\nu}(x-y) \\equiv < B_\\mu(x) B_\\nu(y) >_{\\rm MA}$ in the MA gauge, and\nfind that $G^D_{\\mu\\mu}$ behaves as the massive vector-boson propagator with\n$m_B \\simeq 0.4$ GeV in the infrared region. The effective-mass acquirement of\nthe dual gluon field $B_\\mu$ at the long distance can be regarded as the\nlattice QCD evidence of ``infrared monopole condensation'' in the MA gauge.",
        "positive": "Semi-leptonic decays of heavy mesons: We present results of a lattice computation of the matrix elements of the\nvector currents which are relevant for the semileptonic decays of D to K, D to\npi and B to pi. The computations are performed in the quenched approximation on\na 24^3x48 lattice at beta=6.2, using an O(a) non-perturbatively improved\nfermionic action."
    },
    {
        "anchor": "The Roper Resonance in a finite volume: We calculate the energy levels corresponding to the Roper resonance based on\na two-flavor chiral effective Lagrangian for pions, nucleons, deltas and the\nRoper resonance at leading one-loop order. We show that the Roper mass can be\nextracted from these levels for not too large lattice volumes.",
        "positive": "Strongly Coupled QCD at Finite Baryon Density: The analytical results obtained in the infinite mass and strong coupling\nlimits of QCD are difficult to reconcile with the predictions of the Monomer\nDimer Polymer algorithm. We have reconsidered in detail the results obtained\nwith this simulation scheme and evidences of severe convergence problems are\npresented for the SU(3) and SU(2) gauge group."
    },
    {
        "anchor": "Improved determination of hadron matrix elements using the variational\n  method: The extraction of hadron form factors in lattice QCD using the standard two-\nand three-point correlator functions has its limitations. One of the most\ncommonly studied sources of systematic error is excited state contamination,\nwhich occurs when correlators are contaminated with results from higher energy\nexcitations. We apply the variational method to calculate the axial vector\ncurrent gA and compare the results to the more commonly used summation and\ntwo-exponential fit methods. The results demonstrate that the variational\napproach offers a more efficient and robust method for the determination of\nnucleon matrix elements.",
        "positive": "Vacuum correlators at short distances from lattice QCD: Non-perturbatively computing the hadronic vacuum polarization at large photon\nvirtualities and making contact with perturbation theory enables a precision\ndetermination of the electromagnetic coupling at the $Z$ pole, which enters\nglobal electroweak fits. In order to achieve this goal ab initio using lattice\nQCD, one faces the challenge that, at the short distances which dominate the\nobservable, discretization errors are hard to control. Here we address\nchallenges of this type with the help of static screening correlators in the\nhigh-temperature phase of QCD, yet without incurring any bias. The idea is\nmotivated by the observations that (a) the cost of high-temperature simulations\nis typically much lower than their vacuum counterpart, and (b) at distances\n$x_3$ far below the inverse temperature $1/T$, the operator-product expansion\nguarantees the thermal correlator of two local currents to deviate from the\nvacuum correlator by a relative amount that is power-suppressed in $(x_3\\:T)$.\nThe method is first investigated in lattice perturbation theory, where we point\nout the appearance of an O$(a^2 \\log(1/a))$ lattice artifact in the vacuum\npolarization with a prefactor that we calculate. It is then applied to\nnon-perturbative lattice QCD data with two dynamical flavors of quarks. Our\nlattice spacings range down to 0.049 fm for the vacuum simulations and down to\n0.033 fm for the simulations performed at a temperature of 250 MeV."
    },
    {
        "anchor": "Improving the Dirac Operator in Lattice QCD: Recently various new concepts for the construction of Dirac operators in\nlattice Quantum Chromodynamics (QCD) have been introduced. These operators\nsatisfy the so-called Ginsparg-Wilson condition (GWC), thus obeying the\nAtiyah-Singer index theorem and violating chiral symmetry only in a modest and\nlocal form. Here we present studies in 4-d for SU(3) gauge configurations with\nnon-trivial topological content. We study the flow of eigenvalues and we\ncompare the numerical stability and efficiency of a recently suggested chirally\nimproved operator with that of others in this respect.",
        "positive": "Crumpled triangulations and critical points in 4D simplicial quantum\n  gravity: This is an expanded and revised version of our geometrical analysis of the\nstrong coupling phase of 4D simplicial quantum gravity. The main differences\nwith respect to the former version is a full discussion of singular\ntriangulations with singular vertices connected by a subsingular edge. In\nparticular we provide analytical arguments which characterize the entropical\nproperties of triangulations with a singular edge connecting two singular\nvertices. The analytical estimate of the location of the critical coupling at\nk_2\\simeq 1.3093 is presented in more details. Finally we also provide a model\nfor pseudo-criticality at finite N_4(S^4)."
    },
    {
        "anchor": "Singularities around the QCD critical point in the complex chemical\n  potential plane: We consider thermodynamic singularities appearing in the complex chemical\npotential plane in the vicinity of QCD critical point. In order to investigate\nwhat the singularities are like in a concrete form, we resort to an effective\ntheory based on a mean field approach. We study the behavior of extrema of the\nreal part of the complex effective potential in the complex order parameter\nplane.",
        "positive": "Role of the $\u03c3$-resonance in determining the convergence of chiral\n  perturbation theory: The dimensionless parameter $\\xi = M_\\pi^2/(16 \\pi^2 F_\\pi^2)$, where $F_\\pi$\nis the pion decay constant and $M_\\pi$ is the pion mass, is expected to control\nthe convergence of chiral perturbation theory applicable to QCD. Here we\ndemonstrate that a strongly coupled lattice gauge theory model with the same\nsymmetries as two-flavor QCD but with a much lighter $\\sigma$-resonance is\ndifferent. Our model allows us to study efficiently the convergence of chiral\nperturbation theory as a function of $\\xi$. We first confirm that the leading\nlow energy constants appearing in the chiral Lagrangian are the same when\ncalculated from the $p$-regime and the $\\epsilon$-regime as expected. However,\n$\\xi \\lesssim 0.002$ is necessary before 1-loop chiral perturbation theory\npredicts the data within 1%. For $\\xi > 0.0035$ the data begin to deviate\ndramatically from 1-loop chiral perturbation theory predictions. We argue that\nthis qualitative change is due to the presence of a light $\\sigma$-resonance in\nour model. Our findings may be useful for lattice QCD studies."
    },
    {
        "anchor": "Perturbative Improvement of the Schrodinger Functional for Lattice\n  Strong Dynamics: Lattice simulations on SU(2) and SU(3) gauge theories with matter fields in\nthe fundamental, adjoint and two index symmetric representations are needed to\ndetermine if these theories are near or within the conformal window as required\nfor their applications in beyond standard model phenomenology. Simulations with\nWilson fermion action are subject to artifacts linear in the lattice spacing\n$a$, and must be improved. We provide the necessary coefficients for\nperturbative improvement of the boundary terms when using Schrodinger\nfunctional boundary conditions and furthermore show that correctly implemented\nO(a) improved actions are necessary for reliable results.",
        "positive": "Nucleon form factors and structure functions with N_f=2+1 dynamical\n  domain wall fermions: We report isovector form factors and low moments of structure functions of\nnucleon in numerical lattice quantum chromodynamics (QCD) from the on-going\ncalculations by the RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with\n(2+1) dynamical flavors of domain-wall fermion (DWF) quarks. We calculate the\nmatrix elements with four light quark masses, corresponding to pion mass values\nof m_\\pi = 330-670 MeV, while the dynamical strange mass is fixed at a value\nclose to physical, on (2.7 fm)^3 spatial volume. We found that our axial\ncharge, g_A, at the lightest mass exhibits a large deviation from the heavier\nmass results. This deviation seems to be a finite-size effect as the g_A value\nscales with a single parameter, m_\\pi L, the product of pion mass and linear\nspatial lattice size. The scaling is also seen in earlier 2-flavor dynamical\nDWF and Wilson quark calculations. Without this lightest point, the three\nheavier mass results show only very mild mass dependence and linearly\nextrapolate to g_A=1.16(6). We determined the four form factors, the vector\n(Dirac), induced tensor (Pauli), axial vector and induced pseudoscalar, at a\nfew finite momentum transfer values as well. At the physical pion mass the\nform-factors root mean square radii determined from the momentum-transfer\ndependence %of the form factors are 20-30% smaller than the corresonding\nexperiments. The ratio of the isovector quark momentum to helicity fractions, <\nx>_{u-d}/< x>_{\\Delta u - \\Delta d} is in agreement with experiment without\nmuch mass dependence including the lightest point. We obtain an estimate,\n0.81(2), by a constant fit. Although the individual momentum and helicity\nfractions are yet to be renormalized, they show encouraging trend toward\nexperiment."
    },
    {
        "anchor": "Review of lattice studies of resonances: I review recent progress in extracting resonance parameters using lattice\nfield theory, with an emphasis on determining hadron resonances from lattice\nquantum chromodynamics. Until recently, the \\rho-meson channel was the only one\nconsidered, while, during the last year, several resonant channels have been\ninvestigated for the first time. Recent lattice results for scattering phase\nshifts in resonant channels are presented.",
        "positive": "Scaling properties of many-fermion systems from MCRG studies: Monte Carlo renormalization group methods were designed to study the phase\nstructure and critical behavior of statistical systems. They are well suited to\ndetermine the running coupling and to investigate the properties of fixed\npoints of gauge-fermion models, including the existence of conformal infrared\nfixed points in many-fermion systems. I discuss the implementation of the\n2-lattice matching method and present results for SU(3) gauge theories with\nN_f=0,12 and 16 fundamental fermion flavors."
    },
    {
        "anchor": "Anisotropic Lattice QCD Studies of Penta-quark Anti-decuplet: Anti-decuplet penta-quark baryon is studied with the quenched anisotropic\nlattice QCD for accurate measurement of the correlator. Both the positive and\nnegative parity states are studied using a non-NK type interpolating field with\nI=0 and J=1/2. After the chiral extrapolation, the lowest positive parity state\nis found at m_{Theta} \\simeq 2.25 GeV, which is too massive to be identified\nwith the experimentally observed Theta^+(1540). The lowest negative parity\nstate is found at m_{Theta}\\simeq 1.75 GeV, which is rather close to the\nempirical value. To confirm that this state is a compact 5Q resonance, a new\nmethod with ``hybrid boundary condition (HBC)'' is proposed. The HBC analysis\nshows that the observed state in the negative parity channel is an NK\nscattering state.",
        "positive": "Benchmark Continuum Limit Results for Spectroscopy with Stabilized\n  Wilson Fermions: The OpenLat initiative presents its results of lattice QCD simulations using\nStabilized Wilson Fermions (SWF) using 2+1 quark flavors. Focusing on the\n$\\mathrm{SU}(3)$ flavor symmetric point $m_\\pi=m_K=412$ MeV, four different\nlattice spacings ($a=0.064,0.077,0.094,0.12$ fm) are used to perform the\ncontinuum limit to study cutoff effects. We present results on light hadron\nmasses; for the determination we use a Bayesian analysis framework with\nconstraints and model averaging to minimize the bias in the analysis."
    },
    {
        "anchor": "The free energy in a magnetic field and the universal scaling equation\n  of state for the three-dimensional Ising model: We have substantially extended the high-temperature and low-magnetic-field\n(and the related low-temperature and high-magnetic-field) bivariate expansions\nof the free energy for the conventional three-dimensional Ising model and for a\nvariety of other spin systems generally assumed to belong to the same critical\nuniversality class. In particular, we have also derived the analogous\nexpansions for the Ising models with spin s=1,3/2,.. and for the lattice\neuclidean scalar field theory with quartic self-interaction, on the simple\ncubic and the body-centered cubic lattices. Our bivariate high-temperature\nexpansions, which extend through K^24, enable us to compute, through the same\norder, all higher derivatives of the free energy with respect to the field,\nnamely all higher susceptibilities. These data make more accurate checks\npossible, in critical conditions, both of the scaling and the universality\nproperties with respect to the lattice and the interaction structure and also\nhelp to improve an approximate parametric representation of the critical\nequation of state for the three-dimensional Ising model universality class.",
        "positive": "SU(2) Gauge Theory in $2+1$ Dimensions on a Plaquette Chain Obeys the\n  Eigenstate Thermalization Hypothesis: We test the eigenstate thermalization hypothesis (ETH) for 2+1 dimensional\nSU(2) lattice gauge theory. By considering the theory on a chain of plaquettes\nand truncating basis states for link variables at $j=1/2$, we can map it onto a\nquantum spin chain with local interactions and numerically exactly diagonalize\nthe Hamiltonian for reasonably large lattice sizes. We find energy level\nrepulsion in momentum sectors with no remaining discrete symmetry. We study two\nlocal observables made up of Wilson loops and calculate their matrix elements\nin the energy eigenbasis, which are shown consistent with the ETH."
    },
    {
        "anchor": "$K^{+}\\to\u03c0^{+}\u03c0^{0}$ Decay Amplitude in Quenched Lattice QCD: A new study is reported of a lattice QCD calculation of the $K^+\\to\\pi^+\n\\pi^0 $ decay amplitude with the Wilson quark action in the quenched\napproximation at $\\beta=6.1$. The amplitude is extracted from the $K\\to\\pi\\pi$\nGreen function, and a conversion to the continuum value is made employing a\nrecent one-loop calculation of chiral perturbation theory. The result is\nconsistent with the experimental value if extrapolated to the chiral limit.",
        "positive": "Lattice studies of charmonia and exotics: The lattice QCD simulations of charmonia and exotic charmonium-like states\nare reviewed. I report on the first exploratory simulation of charmonium\nresonances above open charm threshold which takes into account the strong\ndecay. The puzzles related to the first-excited scalar charmonia are discussed.\nEvidence for X(3872) is presented along with investigation of its Fock\ncomponents. The $Z_c^+(3900)$ seems to emerge from the HALQCD approach as a\nresult of the coupled channel effect $J/\\psi \\pi -D\\bar D^*$. The indication\nfor the pentaquark bound state $\\eta_c N$ is presented."
    },
    {
        "anchor": "Induced QCD II: Numerical results: We numerically explore an alternative discretization of continuum\n$\\text{SU}(N_c)$ Yang-Mills theory on a Euclidean spacetime lattice, originally\nintroduced by Budzcies and Zirnbauer for gauge group $\\text{U}(N_c)$. This\ndiscretization can be reformulated such that the self-interactions of the gauge\nfield are induced by a path integral over $N_b$ auxiliary bosonic fields, which\ncouple linearly to the gauge field. In the first paper of the series we have\nshown that the theory reproduces continuum $\\text{SU}(N_c)$ Yang-Mills theory\nin $d=2$ dimensions if $N_b$ is larger than $N_c-\\frac{3}{4}$ and conjectured,\nfollowing the argument of Budzcies and Zirnbauer, that this remains true for\n$d>2$. In the present paper, we test this conjecture by performing lattice\nsimulations of the simplest nontrivial case, i.e., gauge group $\\text{SU}(2)$\nin three dimensions. We show that observables computed in the induced theory,\nsuch as the static $q\\bar q$ potential and the deconfinement transition\ntemperature, agree with the same observables computed from the ordinary\nplaquette action up to lattice artifacts. We also find that the bound for $N_b$\ncan be relaxed to $N_c-\\frac{5}{4}$ as conjectured in our earlier paper.\nStudies of how the new discretization can be used to change the order of\nintegration in the path integral to arrive at dual formulations of QCD are left\nfor future work.",
        "positive": "Effects of Quenching in \u0394I=1/2 Kaon Decays: We present the inconsistencies which arise in quenched QCD in $\\Delta I=1/2$\nnon-leptonic kaon decays using chiral perturbation theory (ChPT) to one loop.\nIn particular we discuss how the lack of unitarity of the quenched theory\ninvalidates the usual methods for the extraction of matrix elements from\ncorrelation functions."
    },
    {
        "anchor": "Nucleon transverse quark spin densities: We present a calculation of the Mellin moments of the nucleon transverse\nquark spin densities extracted from the unpolarized and transversity\ngeneralized form factors. We use three $N_F=2+1+1$ ensembles of twisted mass\nfermions with quark masses tuned to their physical values and lattice spacings\n$a\\sim 0.08$~fm, $a\\sim 0.07$~fm and $a\\sim 0.06$~fm and extrapolate the form\nfactors to the continuum limit. Besides isovector densities we also include\nresults for the tensor charge for each quark flavor using the ensemble with\n$a\\sim 0.08$~fm for which we include the disconnected contributions.",
        "positive": "Precise Determinations of the Decay Constants of B and D mesons: Recently we studied the B, Bs, D and Ds meson decay constants using various\ntreatments for the heavy quark. For B mesons, we determined fB, fBs, and fBs/fB\nwith NRQCD bottom quarks. We then combined the ratio fBs/fB and another very\nprecise determination from HPQCD for fBs using heavy HISQ quarks, and extracted\nfB with 2% total errors. We also calculated fD, fDs, and fDs/fD using HISQ\ncharm quarks. Here we review our results and briefly discuss their implications\nfor the determination of the CKM matrix elements |Vcd| and |Vcs|."
    },
    {
        "anchor": "Exploratory lattice QCD study of the rare kaon decay\n  $K^+\\to\u03c0^+\u03bd\\bar\u03bd$: In Ref [1] we have presented the results of an exploratory lattice QCD\ncomputation of the long-distance contribution to the $K^+\\to\\pi^+\\nu\\bar{\\nu}$\ndecay amplitude. In the present paper we describe the details of this\ncalculation, which includes the implementation of a number of novel techniques.\nThe $K^+\\to\\pi^+\\nu\\bar{\\nu}$ decay amplitude is dominated by short-distance\ncontributions which can be computed in perturbation theory with the only\nrequired non-perturbative input being the relatively well-known form factors of\nsemileptonic kaon decays. The long-distance contributions, which are the target\nof this work, are expected to be of O(5%) in the branching ratio. Our study\ndemonstrates the feasibility of lattice QCD computations of the\n$K^+\\to\\pi^+\\nu\\bar{\\nu}$ decay amplitude, and in particular of the\nlong-distance component. Though this calculation is performed on a small\nlattice ($16^3\\times32$) and at unphysical pion, kaon and charm quark masses,\n$m_\\pi=420$ MeV, $m_K=563$ MeV and $m_c^{\\overline{\\mathrm{MS}}}(\\mbox{2\nGeV})=863$ MeV, the techniques presented in this work can readily be applied to\na future realistic calculation.",
        "positive": "Monte-Carlo simulations of overlap Majorana fermions: Supersymmetric Yang-Mills (SYM) theories in four dimensions exhibit many\ninteresting non-perturbative phenomena that can be studied by means of Monte\nCarlo lattice simulations. However, the lattice regularization breaks\nsupersymmetry explicitly, and in general a fine tuning of a large number of\nparameters is required to correctly extrapolate the theory to the continuum\nlimit. From this perspective, it is important to preserve on the lattice as\nmany symmetries of the original continuum action as possible. Chiral symmetry\nfor instance prevents an additive renormalization of the fermion mass. A\n(modified) version of chiral symmetry can be preserved exactly if the Dirac\noperator fulfills the Ginsparg-Wilson relation. In this contribution, we\npresent an exploratory non-perturbative study of N=1 supersymmetric Yang-Mills\ntheory using the overlap formalism to preserve chiral symmetry at non-zero\nlattice spacings. N=1 SYM is an ideal benchmark toward the extension of our\nstudies to more complex supersymmetric theories, as the only parameter to be\ntuned is the gluino mass. Overlap fermions allow therefore to simulate the\ntheory without fine-tuning. We compare our approach to previous investigations\nof the same theory, and we present clear evidences for gluino condensation."
    },
    {
        "anchor": "Lattice Actions for Yang-Mills Quantum Mechanics with Exact\n  Supersymmetry: We derive lattice actions for Yang-Mills quantum mechanics for models with\n$\\cQ=4, 8$ and 16 supercharges which possess an exact supersymmetry at non-zero\nlattice spacing. These are obtained by dimensional reduction of twisted\nversions of the corresponding super Yang-Mills theories in $D=2, 3$ and 4\ndimensions.",
        "positive": "Lambda-Nucleon and Sigma-Nucleon potentials from space-time correlation\n  function on the lattice: The hyperon-nucleon interaction with the strangeness $S=-1$ region is\ncomplicated and difficult to investigate because its flavor sector involves all\nthe irreducible representation except the flavor singlet and has the worst\nsignal-to-noise ratio among the strangeness regions. In order to overcome such\ndifficulties the content of this report is twofold: (i) We present an\nimplementation of extended effective baryon block algorithm. This is a\nstraightforward extension of the original which was reported in LATTICE 2013.\n(ii) We perform single channel analysis for the $\\Lambda N$ system at nearly\nphysical quark masses corresponding to $(m_\\pi,m_K)\\approx(146,525)$~MeV and\nlarge volume $(La)^4=(96a)^4\\approx$ (8.1 fm)$^4$. Scattering phase shifts for\n$\\Lambda N$ system are presented."
    },
    {
        "anchor": "Gluonic Transversity from Lattice QCD: We present an exploratory study of the gluonic structure of the $\\phi$ meson\nusing lattice QCD (LQCD). This includes the first investigation of gluonic\ntransversity via the leading moment of the twist-two double-helicity-flip\ngluonic structure function $\\Delta(x,Q^2)$. This structure function only exists\nfor targets of spin $J\\ge1$ and does not mix with quark distributions at\nleading twist, thereby providing a particularly clean probe of gluonic degrees\nof freedom. We also explore the gluonic analogue of the Soffer bound which\nrelates the helicity flip and non-flip gluonic distributions, finding it to be\nsaturated at the level of 80%. This work sets the stage for more complex LQCD\nstudies of gluonic structure in the nucleon and in light nuclei where\n$\\Delta(x,Q^2)$ is an 'exotic glue' observable probing gluons in a nucleus not\nassociated with individual nucleons.",
        "positive": "Finite Size Effect in Excited Baryon Spectroscopy: We investigate the finite size effect on masses of excited baryons in\nquenched lattice QCD simulation. For this purpose, we perform numerical\nsimulations at three different lattice sizes, La\\simeq 1.6, 2.2 and 3.2 fm. The\ngauge configurations are generated with the single plaquette gauge action at\n\\beta=6/g^2=6.2, and the quark propagator are computed with the Wilson fermion\naction. To access to two parity states of the nucleon and four different\nspin-parity states of the \\Delta baryon, the appropriate spin/parity projection\nare carried out. We find that the spatial lattice size is required to be as\nlarge as 3 fm to remove the finite size effect on excited baryons even in the\nheavy quark region (M_\\pi/M_\\rho\\simeq 0.82, 0.87), where that on the nucleon\nis negligible. On our largest lattice (La\\simeq 3.2 fm), all mass spectra of\nthe J^P=1/2^\\pm nucleons and the J^P=1/2^\\pm, 3/2^\\pm \\Delta baryons are\nroughly consistent with experimental values after naive chiral extrapolation."
    },
    {
        "anchor": "Two Photon Decays of $\u03b7_c$ from Lattice QCD: We present an exploratory lattice study for the two-photon decay of $\\eta_c$\nusing $N_f=2$ twisted mass lattice QCD gauge configurations generated by the\nEuropean Twisted Mass Collaboration. Two different lattice spacings of\n$a=0.067$fm and $a=0.085$fm are used in the study, both of which are of\nphysical size of 2$fm$. The decay widths are found to be $1.025(5)$KeV for the\ncoarser lattice and $1.062(5)$KeV for the finer lattice respectively where the\nerrors are purely statistical. A naive extrapolation towards the continuum\nlimit yields $\\Gamma\\simeq 1.122(14)$KeV which is smaller than the previous\nquenched result and most of the current experimental results. Possible reasons\nare discussed.",
        "positive": "The large $N$ limit of the topological susceptibility of Yang-Mills\n  gauge theory: We present a precise computation of the topological susceptibility\n$\\chi_{_\\mathrm{YM}}$ of SU$(N)$ Yang-Mills theory in the large $N$ limit. The\ncomputation is done on the lattice, using high-statistics Monte Carlo\nsimulations with $N=3, 4, 5, 6$ and three different lattice spacings. Two major\nimprovements make it possible to go to finer lattice spacing and larger $N$\ncompared to previous works. First, the topological charge is implemented\nthrough the gradient flow definition; and second, open boundary conditions in\nthe time direction are employed in order to avoid the freezing of the\ntopological charge. The results allow us to extrapolate the dimensionless\nquantity $t_0^2\\chi_{_\\mathrm{YM}}$ to the continuum and large $N$ limits with\nconfidence. The accuracy of the final result represents a new quality in the\nverification of large $N$ scaling."
    },
    {
        "anchor": "Twisted mass lattice QCD: I review the theoretical foundations, properties as well as the simulation\nresults obtained so far of a variant of the Wilson lattice QCD formulation:\nWilson twisted mass lattice QCD. Emphasis is put on the discretization errors\nand on the effects of these discretization errors on the phase structure for\nWilson-like fermions in the chiral limit. The possibility to use in lattice\nsimulations different lattice actions for sea and valence quarks to ease the\nrenormalization patterns of phenomenologically relevant local operators, is\nalso discussed.",
        "positive": "Neutron Electric Dipole Moment on the Lattice: a Theoretical Reappraisal: We present a strategy for a lattice evaluation of the neutron electric dipole\nmoment induced by the strong CP violating term of the QCD Lagrangian. Our\nstrategy is based on the standard definition of the electric dipole moment,\ninvolving the charge density operator J0, in case of three flavors with\nnon-degenerate masses. We present a complete diagrammatic analysis showing how\nthe axial chiral Ward identities can be used to replace the opological charge\noperator with the flavor-singlet pseudoscalar density PS. Our final result is\ncharacterized only by disconnected diagrams, where the disconnected part can be\neither the single insertion of PS or the separate insertions of both PS and J0.\nThe applicability of our strategy to the case of lattice formulations that\nexplicitly break chiral symmetry, like the Wilson and Clover actions, is\ndiscussed."
    },
    {
        "anchor": "$B\u03c0$ excited-state contamination in lattice calculations of B-meson\n  correlation functions: Multi-particle states with additional pions are expected to result in a\ndifficult-to-control excited-state contamination in lattice simulations. We\nshow that heavy meson chiral perturbation theory can be employed to estimate\nthe contamination due to two-particle $B\\pi$ states in various $B$-meson\nobservables like the $B$-meson decay constant and the $BB^*\\pi$ coupling. We\nwork in the static limit and to next-to-leading order in the chiral expansion,\ni.e. including $\\rm O(p)$. The $B\\pi$ states are found to typically\noverestimate the observables at the few percent level. We determine two of the\nLECs from $B\\to \\pi$ form factor computations of the KEK group and discuss ways\nto determine the others. In particular two LECs which are associated with\nsmeared interpolating fields seem to be easily accessible and thus open up a\nway to systematically study the effect of smearing on excited state effects.",
        "positive": "Parton Distribution Functions: Parton distribution functions give the probability to find partons (quarks\nand gluons) in a hadron as a function of the fraction x of the proton's\nmomentum carried by the parton. They are conventionally defined in terms of\nmatrix elements of certain operators. They are determined from experimental\nresults on short distance scattering of the partons. Integrals of these\nfunctions weighted with x^n are calculable using lattice QCD. Some simple\nmodels for their behavior have implications that could also be tested in\nlattice QCD."
    },
    {
        "anchor": "A new approach to instanton calculations in the O(3) nonlinear sigma\n  model: We construct all instantons in the \\nlsig\\ on a cylindrical space-time, known\nnot to exist on a finite time interval. The scale parameter, $\\rho$, is related\nto the boundary condition in time. This may cure the $\\rho\\rightarrow0$\ndivergent instanton gas, through a proper inclusion of in and out states in the\npath integral.",
        "positive": "NSPT calculations in the Schrodinger Functional formalism: Within the framework of the Schr\\\"odinger Functional (SF), we outline how to\ncombine Numerical Stochastic Perturbation Theory (NSPT) and PCAC relations to\ndetermine the two-loop contributions to the improvement coefficients $c_A$ and\n$c_{SW}$ for Sheikholeslami-Wohlert-Wilson fermions."
    },
    {
        "anchor": "Properties, ensembles and hadron spectra with Stabilised Wilson Fermions: In this joint contribution we announce the formation of the \"OPEN LATtice\ninitiative\", https://openlat1.gitlab.io, to study Stabilised Wilson Fermions\n(SWF). They are a new avenue for QCD calculations with Wilson-type fermions and\nwe report results on our continued study of this framework: Tuning the clover\nimprovement coefficient, and extending the reach of lattice spacings to\n$a=0.12$ fm. We fix the flavor symmetric points $m_\\pi=m_K=412$ MeV at\n$a=0.055,0.064, 0.077, 0.094, 0.12$ fm and define the trajectories to the\nphysical point by fixing the trace of the quark mass matrix. Currently our pion\nmass range extends down to $m_\\pi\\sim200$ MeV. We outline our tuning goals and\nstrategy as well as our future planned ensembles. First scaling studies are\nperformed on $f_\\pi$ and $m_\\pi$. Additionally results of a preliminary\ncontinuum extrapolation of $m_N$ at the flavor symmetric point are presented.\nGoing further a first determination of the light and strange hadron spectrum\nchiral dependence is shown, which serves to check the quality of the action for\nprecision measurements. We also investigate other quantities such as flowed\ngauge observables to study how the continuum limit is approached. Taken\ntogether we observe the SWF enable us to perform stable lattice simulations\nacross a large range of parameters in mass, volume and lattice spacing. Pooling\nresources our new initiative has made our reported progress possible and\nthrough it we will share generated gauge ensembles under an open science\nphilosophy.",
        "positive": "Lattice formulation of (2,2) supersymmetric gauge theories with matter\n  fields: We construct lattice actions for a variety of (2,2) supersymmetric gauge\ntheories in two dimensions with matter fields interacting via a superpotential."
    },
    {
        "anchor": "Lattice QCD with $N_f = 2+1+1 $ domain-wall quarks: We perform hybrid Monte Carlo simulation of (2+1+1)-flavors lattice QCD with\nthe optimal domain-wall fermion (which has the effective 4D Dirac operator\nexactly equal to the Zolotarev optimal rational approximation of the overlap\nDirac operator). The gauge ensemble is generated on the $32^3 \\times 64 $\nlattice with the extent $ N_s = 16 $ in the fifth dimension, and with the\nplaquette gauge action at $ \\beta = 6/g^2 = 6.20 $. The lattice spacing ($ a\n\\simeq 0.063 $ fm) is determined by the Wilson flow, using the value $\n\\sqrt{t_0} = 0.1416(8) $ fm obtained by the MILC Collaboration for the\n$(2+1+1)$-flavors QCD. The masses of $s$ and $c$ quarks are fixed by the masses\nof the vector mesons $ \\phi(1020) $ and $ J/\\psi(3097) $ respectively; while\nthe mass of the $u/d$ quarks is heavier than their physical values, with the\nunitary pion mass $ M_\\pi \\simeq 280$ MeV (and $ M_\\pi L \\simeq 3 $). We\ncompute the point-to-point quark propagators, and measure the time-correlation\nfunctions of meson and baryon interpolators. Our results of the mass spectra of\nthe lowest-lying hadrons containing $ s $ and $ c $ quarks are in good\nagreement with the high energy experimental values, together with the\npredictions of the charmed baryons which have not been observed in experiments.",
        "positive": "Universal properties of large N phase transitions in Wilson loops: Numerical studies support the conjecture that in continuum planar QCD the\neigenvalue density of a Wilson loop operator undergoes a transition as the loop\nis dilated while keeping the loop shape fixed. A second part of the conjecture\nis that the transition obeys large N universality and that this universality\nclass is the same in 2, 3 and 4 Euclidean space-time dimensions. The focus of\nthe talk will be on clarifying precisely what the conjecture is claiming."
    },
    {
        "anchor": "Critical behaviour of the compact 3d U(1) gauge theory at finite\n  temperature: Critical properties of the compact three-dimensional U(1) lattice gauge\ntheory are explored at finite temperatures. The critical point of the\ndeconfinement phase transition, critical indices and the string tension are\nstudied numerically on lattices with temporal extension N_t = 8 and spatial\nextension ranging from L = 32 to L = 256. The critical indices, which govern\nthe behaviour across the deconfinement phase transition, are generally expected\nto coincide with the critical indices of the two-dimensional XY model. It is\nfound that the determination of the infinite volume critical point differs from\nthe pseudo-critical coupling at L = 32, found earlier in the literature and\nimplicitly assumed as the onset value of the deconfined phase. The critical\nindex $\\nu$ computed from the scaling of the pseudocritical couplings agrees\nwell with the value $\\nu$ = 1/2 of the XY model. The computation of the index\n$\\eta$ brings to a value larger than expected. The possible reasons for such\nbehaviour are discussed.",
        "positive": "Electromagnetic Structure of Light Baryons in Lattice QCD: A method for computing electromagnetic properties of hadrons in lattice QCD\nis applied to the extraction of electromagnetic properties of the octet\nbaryons. This allows a determination of the full dependence of the baryon\nmasses on the charges and masses of the valence quarks. Results of a first\nnumerical study (at $\\beta=5.7$ with Wilson action and light quark masses fixed\nfrom the pseudoscalar meson spectrum) are reported. The octet baryon\nisomultiplet splittings (with statistical errors) are found to be: ${\\rm N} -\n{\\rm P} = 1.55(\\pm 0.56)$, $\\Sigma^0 - \\Sigma^+ = 2.47(\\pm 0.39)$, $\\Sigma^- -\n\\Sigma^0 = 4.63(\\pm 0.36)$ and $\\Xi^- - \\Xi^0 = 5.68(\\pm 0.24)$ MeV. Estimates\nof the systematic corrections arising from finite volume and the quenched\napproximation are included in these results."
    },
    {
        "anchor": "Is SU(3) gauge theory with 13 massless flavors conformal?: We use lattice simulations to study SU(3) gauge theory with 13 massless\nfermions in the fundamental representation. We present evidence that the theory\nis conformal with a non-zero infrared fixed point in the gauge coupling. We use\na newly-developed technique to calculate the mass anomalous dimension at the\nfixed point via step-scaling of the mode number, allowing us to take the\ncontinuum limit and compare to perturbative predictions. We comment on the\nrelevance of these findings to the extended search for the conformal window in\nthe fundamental representation and in particular 12 massless flavors.",
        "positive": "Chiral transition and monopole percolation in lattice scalar QED with\n  quenched fermions: We study the interplay between topological observables and chiral and Higgs\ntransitions in lattice scalar QED with quenched fermions. Emphasis is put on\nthe chiral transition line and magnetic monopole percolation at strong gauge\ncoupling. We confirm that at infinite gauge coupling the chiral transition is\ndescribed by mean field exponents. We find a rich and complicated behaviour at\nthe endpoint of the Higgs transition line which hampers a satisfactory analysis\nof the chiral transition. We study in detail an intermediate coupling, where\nthe data are consistent both with a trivial chiral transition clearly separated\nfrom monopole percolation and with a chiral transition coincident with monopole\npercolation, and characterized by the same critical exponent $\\nu \\simeq 0.65$.\nWe discuss the relevance (or lack thereof) of these quenched results to our\nunderstanding of the \\chupiv\\ model. We comment on the interplay of magnetic\nmonopoles and fermion dynamics in more general contexts."
    },
    {
        "anchor": "Minimally doubled chiral fermions with C, P and T symmetry on the\n  staggered lattice: Recently, the interest in local lattice actions for chiral fermions has\nrevived, with the proposition of new local actions in which only the minimal\nnumber of doublers appear. The trigger role of graphene having a minimally\ndoubled, chirally invariant, Dirac-like excitation spectrum can not be\nneglected. The challenge is to construct an action which preserves enough\nsymmetries to be useful in lattice gauge calculations. We present a new\napproach to obtain local lattice actions for fermions using a reinterpretation\nof the staggered lattice approach of Kogut and Susskind. This interpretation is\nbased on the similarity with the staggered lattice approach in FDTD simulations\nof acoustics and electromagnetism. It allows us to construct a local action for\nchiral fermions which has all discrete symmetries and the minimal number of\nfermion flavors, but which is non-Hermitian in real space. However, we argue\nthat this will not pose a threat to the usability of the theory.",
        "positive": "Quark number susceptibilities and equation of state at finite chemical\n  potential in staggered QCD with Nt=8: We report the measurement of quark number susceptibilities (QNS) and their\ntemperature dependence from simulations of QCD with two flavours of light\ndynamical staggered quarks at finite temperature on 8 * 32^3 lattices. From the\nradius of convergence of the Taylor expansion we estimate the critical end\npoint. We use a Pade approximant to resum the series expansion and compute the\nequation of state at finite chemical potential, namely the baryon number\ndensity and its contribution to the pressure. We also report the isothermal\ncompressibility of QCD matter at finite baryon density. Finally we explore the\nfreezeout conditions for a measure of fluctuations. We examine some sources of\nsystematic and statistical errors in all of these measurements."
    },
    {
        "anchor": "Spectral Properties of the Wilson Dirac Operator and random matrix\n  theory: Random Matrix Theory has been successfully applied to lattice Quantum\nChromodynamics. In particular, a great deal of progress has been made on the\nunderstanding, numerically as well as analytically, of the spectral properties\nof the Wilson Dirac operator. In this paper, we study the infra-red spectrum of\nthe Wilson Dirac operator via Random Matrix Theory including the three leading\norder $a^2$ correction terms that appear in the corresponding chiral\nLagrangian. A derivation of the joint probability density of the eigenvalues is\npresented. This result is used to calculate the density of the complex\neigenvalues, the density of the real eigenvalues and the distribution of the\nchiralities over the real eigenvalues. A detailed discussion of these\nquantities shows how each low energy constant affects the spectrum. Especially\nwe consider the limit of small and large (which is almost the mean field limit)\nlattice spacing. Comparisons with Monte Carlo simulations of the Random Matrix\nTheory show a perfect agreement with the analytical predictions. Furthermore we\npresent some quantities which can be easily used for comparison of lattice data\nand the analytical results.",
        "positive": "Lattice QCD for Precision Nucleon Matrix Elements: Precision measurements on nucleons provide constraints on the Standard Model\nand can also discern the signatures predicted for particles beyond the Standard\nModel. Knowing the Standard Model inputs to nucleon matrix elements will be\nnecessary to constrain the couplings of dark matter candidates such as the\nneutralino, to relate the neutron electric dipole moment to the CP-violating\ntheta parameter, or to search for new TeV-scale particles though non-$V-A$\ninteractions in neutron beta decay. However, these matrix elements derive from\nthe properties of quantum chromodynamics (QCD) at low energies, where the\ncoupling is strong and thus perturbative treatments fail. Using lattice gauge\ntheory, we can nonperturbatively calculate the QCD path integral on a\nsupercomputer.\n  In this proceeding, I will review a few representative areas in which lattice\nQCD can contribute to understanding the structure inside nucleon and how they\ncan contribute to the search for beyond-the-Standard Model physics, with\ndiscussions of the difficulties and prospects for future development."
    },
    {
        "anchor": "Effects of the low lying Dirac modes on the spectrum of ground state\n  mesons: The lowest eigenmodes of the Dirac operator are related to the dynamical\nbreaking of the chiral symmetry in Quantum Chromodynamics (QCD). In our work we\nconstruct quark propagators which exclude a varying number of the lowest Dirac\neigenmodes and study the influence thereof on meson correlators and the meson\nspectrum. That procedure partially restores the chiral symmetry (in the valence\nsector) and we observe degeneracies in the spectrum while confinement seems not\nto be affected.",
        "positive": "The domain wall fermion chiral condensate in quenched QCD: We examine the chiral limit of domain wall fermions in quenched QCD. One\nexpects that in a quenched simulation, exact fermion zero modes will give a\ndivergent, 1/m behavior in the chiral condensate for sufficiently small valence\nquark masses. Unlike other fermion formulations, domain wall fermions clearly\ndemonstrate this behavior."
    },
    {
        "anchor": "Singlet channel scattering in a Composite Higgs model on the lattice: We present the first calculation of the scattering amplitude in the singlet\nchannel beyond QCD. The calculation is performed in $SU(2)$ gauge theory with\n$N_f=2$ fundamental Dirac fermions and based on a finite-volume scattering\nformalism. The theory exhibits a $SU(4) \\to Sp(4)$ chiral symmetry breaking\npattern that is used to design minimal composite Higgs models currently tested\nat the LHC. Our results show that, for the range of underlying fermion mass\nconsidered, the lowest flavour singlet state is stable.",
        "positive": "Measure dependence of 2D simplicial quantum gravity: We study pure 2D Euclidean quantum gravity with $R^2$ interaction on\nspherical lattices, employing Regge's formulation. We attempt to measure the\nstring susceptibility exponent $\\gamma_{\\rm str}$ by using a finite-size\nscaling Ansatz in the expectation value of $R^2$. To check on effects of the\npath integral measure we investigate two scale invariant measures, the\n\"computer\" measure $dl/l$ and the Misner measure $dl/\\sqrt A$."
    },
    {
        "anchor": "Provenance for Lattice QCD workflows: We present a provenance model for the generic workflow of numerical Lattice\nQuantum Chromodynamics (QCD) calculations, which constitute an important\ncomponent of particle physics research. These calculations are carried out on\nthe largest supercomputers worldwide with data in the multi-PetaByte range\nbeing generated and analyzed. In the Lattice QCD community, a custom metadata\nstandard (QCDml) that includes certain provenance information already exists\nfor one part of the workflow, the so-called generation of configurations.\n  In this paper, we follow the W3C PROV standard and formulate a provenance\nmodel that includes both the generation part and the so-called measurement part\nof the Lattice QCD workflow. We demonstrate the applicability of this model and\nshow how the model can be used to answer some provenance-related research\nquestions. However, many important provenance questions in the Lattice QCD\ncommunity require extensions of this provenance model. To this end, we propose\na multi-layered provenance approach that combines prospective and retrospective\nelements.",
        "positive": "An Introduction to Finite Temperature Quantum Chromodynamics on the\n  Lattice: In these lectures, we introduce finite temperature QCD on the lattice to\nnon-experts of the subject. We first formulate lattice QCD both at zero and\nfinite temperatures. Then a section is devoted to the topic of improved lattice\nactions which are becoming an essential ingredient of precision studies of QCD\non the lattice. We then discuss about finite temperature SU(3) gauge theory,\ni.e. QCD without dynamical quarks (quenched QCD). Finally, we report recent\nstatus of studies in full QCD taking into account the effects of dynamical\nquarks."
    },
    {
        "anchor": "Simulation of a modified Hubbard model with a chemical potential using a\n  meron-cluster algorithm: We show how a variant of the Hubbard model can be simulated using a\nmeron-cluster algorithm. This provides a major improvement in our ability to\ndetermine the behavior of these types of models. We also present some results\nthat clearly demonstrate the existence of a superconducting state in this\nmodel.",
        "positive": "Recent MILC spectrum results: We report on results from three spectrum calculations with staggered quarks:\n1) a quenched calculation with the standard action for the gluons and quarks;\n2) a quenched calculation with improved actions for both the gluons and quarks;\nand 3) a calculation with two flavors of dynamical quarks using the standard\nactions for the gluons and quarks."
    },
    {
        "anchor": "Y-type Flux-Tube Formation in Baryons: For more than 300 different patterns of the 3Q systems, the ground-state 3Q\npotential $V_{\\rm 3Q}^{\\rm g.s.}$ is investigated using SU(3) lattice QCD with\n$12^3\\times 24$ at $\\beta=5.7$ and $16^3\\times 32$ at $\\beta=5.8, 6.0$ at the\nquenched level. As a result of the detailed analyses, we find that the\nground-state potential $V_{\\rm 3Q}^{\\rm g.s.}$ is well described with so-called\nY-ansatz as $V_{\\rm 3Q}=-A_{\\rm 3Q}\\sum_{i<j}\\frac1{|{\\bf r}_i-{\\bf r}_j|}\n+\\sigma_{\\rm 3Q} L_{\\rm min}+C_{\\rm 3Q}$, with the accuracy better than 1%.\nHere, $L_{\\rm min}$ denotes the minimal value of total flux-tube length. We\nalso studythe excited-state potential $V_{\\rm 3Q}^{\\rm e.s.}$ using lattice QCD\nwith $16^3\\times 32$ at $\\beta=5.8, 6.0$ for more than 100 patterns of the 3Q\nsystems. The energy gap between $V_{\\rm 3Q}^{\\rm g.s.}$ and $V_{\\rm 3Q}^{\\rm\ne.s.}$, which physically means the gluonic excitation energy, is found to be\nabout 1 GeV in the typical hadronic scale. Finally, we suggest a possible\nscenario which connects the success of the quark model to QCD.",
        "positive": "f_K/f_pi in Full QCD with Domain Wall Valence Quarks: We compute the ratio of pseudoscalar decay constants f_K/f_pi using\ndomain-wall valence quarks and rooted improved Kogut-Susskind sea quarks. By\nemploying continuum chiral perturbation theory, we extract the Gasser-Leutwyler\nlow-energy constant L_5, and extrapolate f_K/f_pi to the physical point. We\nfind: f_K/f_pi = 1.218 (+- 0.002) (+0.011 -0.024) where the first error is\nstatistical and the second error is an estimate of the systematic due to chiral\nextrapolation and fitting procedures. This value agrees within the\nuncertainties with the determination by the MILC collaboration, calculated\nusing Kogut-Susskind valence quarks, indicating that systematic errors arising\nfrom the choice of lattice valence quark are small."
    },
    {
        "anchor": "Dispersion relation and unphysical poles of M\u00f6bius domain-wall\n  fermions in free field theory at finite $L_s$: We investigate the dispersion relation of M\\\"obius domain-wall fermions in\nfree field theory at finite $L_s$. We find that there are $L_s-1$ extra poles\nof M\\\"obius domain-wall fermions in addition to the pole which realizes the\nphysical mode in the continuum limit. The unphysical contribution of these\nextra poles could be significant when we introduce heavy quarks. We show in\nthis report the fundamental properties of these unphysical poles and discuss\nthe optimal choice of M\\\"obius parameters to minimize their contribution to\nfour-dimensional physics.",
        "positive": "Quark-gluon vertex in general kinematics: We compute the quark-gluon vertex in quenched lattice QCD, in the Landau\ngauge using an off-shell mean-field O(a)-improved fermion action. The\nDirac-vector part of the vertex is computed for arbitrary kinematics. We find a\nsubstantial infrared enhancement of the interaction strength regardless of the\nkinematics."
    },
    {
        "anchor": "Testing the event-chain algorithm in asymptotically free models: We apply the event-chain algorithm proposed by Bernard, Krauth and Wilson in\n2009 to toy models of lattice QCD. We give a formal prove of stability of the\nalgorithm. We study its performance at the example of the massive Gaussian\nmodel on the square and the simple cubic lattice, the $O(3)$-invariant\nnon-linear $\\sigma$-model and the $SU(3) \\times SU(3)$ principle chiral model\non the square lattice. In all these cases we find that critical slowing down is\nessentially eliminated.",
        "positive": "Quark propagators at finite temperature with the clover action: We study properties of the finite temperature quark propagator by using the\nSU(3) quenched lattice simulation in the Landau gauge and report numerical\nresults of the standard Wilson quark case as well as the improved clover one.\nThe mass function in the deconfinement phase is different from that of the\nconfinement phase, especially at low momentum regions."
    },
    {
        "anchor": "Gauge-ball spectrum of the four-dimensional pure U(1) gauge theory: We investigate the continuum limit of the gauge-ball spectrum in the\nfour-dimensional pure U(1) lattice gauge theory. In the confinement phase we\nidentify various states scaling with the correlation length exponent $\\nu\n\\simeq 0.35$. The square root of the string tension also scales with this\nexponent, which agrees with the non-Gaussian fixed point exponent recently\nfound in the finite size studies of this theory. Possible scenarios for\nconstructing a non-Gaussian continuum theory with the observed gauge-ball\nspectrum are discussed. The $0^{++}$ state, however, scales with a Gaussian\nvalue $\\nu \\simeq 0.5$. This suggests the existence of a second, Gaussian\ncontinuum limit in the confinement phase and also the presence of a light or\npossibly massless scalar in the non-Gaussian continuum theory. In the Coulomb\nphase we find evidence for a few gauge-balls, being resonances in multi-photon\nchannels; they seem to approach the continuum limit with as yet unknown\ncritical exponents. The maximal value of the renormalized coupling in this\nphase is determined and its universality confirmed.",
        "positive": "Magnetic field effects on the static quark potential at zero and finite\n  temperature: We investigate the static $Q\\bar{Q}$ potential at zero and finite temperature\nin the presence of a constant and uniform external magnetic field $\\vec{B}$,\nfor several values of the lattice spacing and for different orientations with\nrespect to $\\vec{B}$. As a byproduct, we provide continuum limit extrapolated\nresults for the string tension, the Coulomb coupling and the Sommer parameter\nat $T = 0$ and $B = 0$. We confirm the presence in the continuum of a\n$B$-induced anisotropy, regarding essentially the string tension, for which it\nis of the order of 15\\% at $|e| B \\sim 1~{\\rm GeV}^2$ and would suggest, if\nextrapolated to larger fields, a vanishing string tension along the magnetic\nfield for $|e| B \\gtrsim 4$ GeV$^2$. The angular dependence for $|e| B \\lesssim\n1$ GeV$^2$ can be nicely parametrized by the first allowed term in an angular\nFourier expansion, corresponding to a quadrupole deformation. Finally, for $T\n\\neq 0$, the main effect of the magnetic field is a general suppression of the\nstring tension, leading to a precocious loss of the confining properties: this\nhappens even before the appearance of inverse magnetic catalysis in the chiral\ncondensate, supporting the idea that the influence of the magnetic field on the\nconfining properties is the leading effect originating the decrease of $T_c$ as\na function of $B$."
    },
    {
        "anchor": "Particle Mesh Ewald's Method and Non-Interacting Dyon Gas: We study the free energy of a quark-antiquark pair near the deconfinement\ntemperature by particle mesh Ewald's method for non-interacting dyon ensemble.\nWe show that the free energy of the quark-antiquark pair increases linearly by\nincreasing the distance between them. The string tension decreases by\nincreasing the temperature, as expected.",
        "positive": "Lattice QCD study of four-quark components of the isosinglet scalar\n  mesons: Significance of disconnected diagrams: We study the possible significance of four-quark states in the iso-singlet\nscalar mesons ($J^{PC}=0^{++}$, $I=0$) by performing two-flavor full lattice\nQCD simulations on an $8^3 \\times 16$ lattice using the improved gauge action\nand the clover-improved Wilson quark action. In particular, we evaluate the\npropagators of molecular and tetra-quark operators together with singly\ndisconnected diagrams. In the computation of the singly disconnected diagrams\nwe employ the $Z_2$-noise method with the truncated eigenmode approach. We show\nthat the quark loops given by the disconnected diagrams play an essential role\nin propagators of tetraquark and molecular operators."
    },
    {
        "anchor": "The Nf=2 residual mass in Perturbative Lattice-HQET for an improved\n  determination of the (MS bar) b-quark mass: We determine to order alpha^3 the so-called residual mass in the lattice\nregularisation of the Heavy Quark Effective Theory for Nf=2. Our\n(gauge-invariant) strategy makes use of Numerical Stochastic Perturbation\nTheory to compute the static interquark potential where the above mentioned\nmass term appears as an additive contribution. We discuss how the new\ncoefficient we compute in the expansion of the residual mass can improve the\ndetermination of the (MS bar) mass of the b-quark from lattice simulations of\nthe Heavy Quark Effective Theory.",
        "positive": "Solving Lattice QCD systems of equations using mixed precision solvers\n  on GPUs: Modern graphics hardware is designed for highly parallel numerical tasks and\npromises significant cost and performance benefits for many scientific\napplications. One such application is lattice quantum chromodyamics (lattice\nQCD), where the main computational challenge is to efficiently solve the\ndiscretized Dirac equation in the presence of an SU(3) gauge field. Using\nNVIDIA's CUDA platform we have implemented a Wilson-Dirac sparse matrix-vector\nproduct that performs at up to 40 Gflops, 135 Gflops and 212 Gflops for double,\nsingle and half precision respectively on NVIDIA's GeForce GTX 280 GPU. We have\ndeveloped a new mixed precision approach for Krylov solvers using reliable\nupdates which allows for full double precision accuracy while using only single\nor half precision arithmetic for the bulk of the computation. The resulting\nBiCGstab and CG solvers run in excess of 100 Gflops and, in terms of iterations\nuntil convergence, perform better than the usual defect-correction approach for\nmixed precision."
    },
    {
        "anchor": "Effects of spatial size, lattice doubling and source operator on the\n  hadron spectrum with dynamical staggered quarks: We have extended our previous study of the lattice QCD spectrum with 2\nflavors of staggered dynamical quarks at $6/g^2=5.6$ and $am_q=0.025$ and 0.01\nto larger lattices, with better statistics and with additional sources for the\npropagators. The additional sources allowed us to estimate the $\\Delta$ mass\nand to measure the masses of all mesons whose operators are local in time.\nThese mesons show good evidence for flavor symmetry restoration, except for the\nmasses of the Goldstone and non-Goldstone pions. PCAC is observed in that\n$m_\\pi^2 \\propto m_q$, and $f_\\pi$ is estimated. Use of undoubled lattices\nremoves problems with the pion propagator found in our earlier work. Previously\nwe found a large change in the nucleon mass at a quark mass of $am_q=0.01$ when\nwe increased the spatial size from 12 to 16. No such effect is observed at the\nlarger quark mass, $am_q=0.025$. Two kinds of wall source were used, and we\nhave found difficulties in getting consistent results for the nucleon mass\nbetween the two sources.",
        "positive": "BB interactions with static bottom quarks from Lattice QCD: The isospin, spin and parity dependent potential of a pair of $B$ mesons is\ncomputed using Wilson twisted mass lattice QCD with two flavours of degenerate\ndynamical quarks. The $B$ meson is addressed in the static-light approximation,\ni.e.\\ the $b$ quarks are infinitely heavy. From the results of the $B\\,B$\nmeson-meson potentials, a simple rule can be deduced stating which isospin,\nspin and parity combinations correspond to attractive and which to repulsive\nforces. We provide fits to the ground state potentials in the attractive\nchannels and discuss the potentials in the repulsive and excited channels. The\nattractive channels are most important since they can possibly lead to a bound\nfour-quark state, i.e.\\ a $\\bar{b}\\bar{b}ud$ tetraquark. Using these attractive\npotentials in the Schr\\\"odinger equation, we find indication for such a\ntetraquark state of two static bottom antiquarks and two light $u/d$ quarks\nwith mass extrapolated down to the physical value."
    },
    {
        "anchor": "A stabilizing kernel for complex Langevin simulations of real-time gauge\n  theories: The complex Langevin (CL) method is a promising approach to overcome the sign\nproblem, which emerges in real-time formulations of quantum field theories.\nOver the past decade, stabilization techniques for CL have been developed with\nimportant applications in finite density QCD. However, they are insufficient\nfor SU($N_c$) gauge theories on a Schwinger-Keldysh time contour that is\nrequired for a real-time formulation. In these proceedings we revise the\ndiscretization of the real-time CL equations and introduce a novel anisotropic\nkernel that enables CL simulations on discretized time contours. Applying it to\nSU(2) Yang-Mills theory in 3+1 dimensions, we obtain unprecedentedly stable\nresults that may allow us to calculate real-time observables from first\nprinciples.",
        "positive": "Lattice study of nucleon properties with domain wall fermions: Domain wall fermions (DWF) are a new fermion discretization scheme with\ngreatly improved chiral symmetry. Our final goal is to study the nucleon spin\nstructure through lattice simulation using DWF. In this paper, we present our\ncurrent progress on two topics toward this goal: 1) the mass spectrum of the\nnucleon excited states and 2) the iso-vector vector and axial charges, $g_{V}$\nand $g_{A}$, of the nucleon."
    },
    {
        "anchor": "Continuum extrapolation of critical point for finite temperature QCD\n  with Nf=3: We study the critical point for finite temperature Nf=3 QCD using several\ntemporal lattice sizes up to 10. In the study, the Iwasaki gauge action and\nnon-perturbatively O(a) improved Wilson fermions are employed. We estimate the\ncritical temperature and the upper bound of the critical pseudo-scalar meson\nmass.",
        "positive": "A lattice investigation of exotic tetraquark channels: We perform an $n_f=2+1$ lattice study of a number of channels where past\nclaims exist in the literature for the existence of strong-interaction-stable\nlight-heavy tetraquarks. We find no evidence for any such deeply-bound states,\nbeyond the $J^P=1^+$, $I=0$ $ud\\bar{b}\\bar{b}$ and $I=1/2$ $ls\\bar{b}\\bar{b}$\nstates already identified in earlier lattice studies. We also describe a number\nof systematic improvements to our previous lattice studies, including working\nwith larger $m_\\pi L$ to better suppress possible finite volume effects,\nemploying extended sinks to better control excited-state contamination, and\nexpanding the number of operators used in the GEVP analyses. Our results also\nallow us to rule out several phenomenological models which predict significant\ntetraquark binding in channels where no such binding is found."
    },
    {
        "anchor": "Non-perturbative renormalisation of Delta F=2 four-fermion operators in\n  two-flavour QCD: Using Schroedinger Functional methods, we compute the non-perturbative\nrenormalisation and renormalisation group running of several four-fermion\noperators, in the framework of lattice simulations with two dynamical Wilson\nquarks. Two classes of operators have been targeted: (i) those with left-left\ncurrent structure and four propagating quark fields; (ii) all operators\ncontaining two static quarks. In both cases, only the parity-odd contributions\nhave been considered, being the ones that renormalise multiplicatively. Our\nresults, once combined with future simulations of the corresponding lattice\nhadronic matrix elements, may be used for the computation of phenomenological\nquantities of interest, such as B_K and B_B (the latter also in the static\nlimit).",
        "positive": "Monopole classical solutions and the vacuum structure in lattice gauge\n  theories: Classical solutions corresponding to monopole-antimonopole pairs are found in\n3d and 4d SU(2) and U(1) lattice gauge theories. The stability of these\nsolutions in different theories is studied."
    },
    {
        "anchor": "I=2 Pion Scattering Length with the Wilson Fermion: The calculation of the I=2 pion scattering length in quenched lattice QCD is\nrevisited. The calculation is carried out with the Wilson fermion action\nemploying L\\\"uscher's finite size scaling method at $\\beta=5.9$, 6.1, and 6.3\ncorresponding to the range of lattice spacing $a\\simeq 0.12 - 0.07$ fm. We\nobtain in the continuum limit $a_0m_\\pi = -0.0410(69)$, which is consistent\nwith the prediction of chiral perturbation theory $a_0m_\\pi=-0.0444(10)$.",
        "positive": "Confining proprties of a gas of Z(2) vortices: Vortex solutions are studied in an SO(3) gauge theory spontaneously broken to\nSO(2). These vortices have a Z(2) magnetic charge. A dilute gas of Z(2)\nvortices is studied taking into account vortex-vortex interactions. By going to\na dual representation we show that odd charges are confined with a string\ntension which decreases exponentially with the inverse coupling."
    },
    {
        "anchor": "Scaling study of the gluon propagator in Coulomb gauge QCD on isotropic\n  and anisotropic lattices: We calculate the transverse and time-time components of the instantaneous\ngluon propagator in Coulomb gauge QCD by using an SU(3) quenched lattice\nsimulation on isotropic and anisotropic lattices. We find that the gluon\npropagators suffer from strong discretization effects on the isotropic lattice;\non the other hand, those on the anisotropic lattices give a better scaling.\nMoreover, on these two type of lattices the transverse parts are significantly\nsuppressed in the infrared region and have a turnover at about 500 [MeV]. The\nhigh resolution to the temporal direction due to the anisotropy yields small\ndiscretization errors for the time-time gluon propagators, which also show an\ninfrared enhancement as expected in the Gribov-Zwanziger confinement scenario.",
        "positive": "Dynamical QCD simulation with theta terms: The theta term that breaks the Strong CP symmetry is introduced in the two\nflavors of dynamical QCD simulation. theta is analytically continued to a pure\nimaginary number to make the probability of Monte Carlo positive. The Neutron's\nElectric Dipole Moment (NEDM) is measured on the ensemble under a uniform and\nweek electric field. Other applications of theta terms are also discussed."
    },
    {
        "anchor": "Thermal dilepton rate and electrical conductivity: An analysis of vector\n  current correlation functions in quenched lattice QCD: We calculate the vector current correlation function for light valence quarks\nin the deconfined phase of QCD. The calculations have been performed in\nquenched lattice QCD at T=1.45 Tc for four values of the lattice cut-off on\nlattices up to size 128^3x48. This allows to perform a continuum extrapolation\nof the correlation function in the Euclidean time interval tau*T -in [0.2,\n0.5], which extends to the largest temporal separations possible at finite\ntemperature, to better than 1% accuracy. In this interval, at the value of the\ntemperature investigated, we find that the vector correlation function never\ndeviates from the free correlator for massless quarks by more than 9%. We also\ndetermine the first two non-vanishing thermal moments of the vector meson\nspectral function. The second thermal moment deviates by less than 7% from the\nfree value. With these constraints, we then proceed to extract information on\nthe spectral representation of the vector correlator and discuss resulting\nconsequences for the electrical conductivity and the thermal dilepton rate in\nthe plasma phase.",
        "positive": "Generalized Ginsparg-Wilson algebra and index theorem on the lattice: Recent studies of the topological properties of a general class of lattice\nDirac operators are reported. This is based on a specific algebraic realization\nof the Ginsparg-Wilson relation in the form\n  $\\gamma_{5}(\\gamma_{5}D)+(\\gamma_{5}D)\\gamma_{5} =\n  2a^{2k+1}(\\gamma_{5}D)^{2k+2}$ where $k$ stands for a non-negative integer.\nThe choice $k=0$ corresponds to the commonly discussed Ginsparg-Wilson relation\nand thus to the overlap operator. It is shown that local chiral anomaly and the\ninstanton-related index of all these operators are identical. The locality of\nall these Dirac operators for vanishing gauge fields is proved on the basis of\nexplicit construction, but the locality with dynamical gauge fields has not\nbeen established yet. We suggest that the Wilsonian effective action is\nessential to avoid infrared singularities encountered in general perturbative\nanalyses."
    },
    {
        "anchor": "Lattice B-parameters for $\u0394S = 2$ and $\u0394I = 3/2$ Operators: We compute several matrix elements of dimension-six four-fermion operators\nand extract their B-parameters. The calculations have been performed with the\ntree-level Clover action at $\\beta = 6.0$. The renormalization constants and\nmixing coefficients of the lattice operators have been obtained\nnon-perturbatively. In the $\\MSbar$ renormalization scheme, at a\nrenormalization scale $\\mu \\simeq 2$ GeV, we find $B_K (B_9^{3/2}) = 0.66(11),\nB_7^{3/2} = 0.72(5)$ and $B_8^{3/2} = 1.03(3)$. The result for $B_8^{3/2}$ has\nimportant implications for the calculation of $\\epsilon^\\prime / \\epsilon$.",
        "positive": "Lattice QCD equation of state : improving the differential method: We propose an improvement of the differential method for the computation of\nthe equation of state of QCD from lattice simulations. In contrast to the\nearlier differential method our technique yields positive pressure for all\ntemperatures including in the transition region. Employing it on temporal\nlattices of 8, 10 and 12 sites and by extrapolating to zero lattice spacing we\nobtained the pressure, energy density, entropy density, specific heat and speed\nof sound in quenched QCD for 0.9 < T/Tc < 3. A comparison of our results is\nmade with those from the dimensional reduction approach and a conformal\nsymmetric theory at high-temperature."
    },
    {
        "anchor": "Diquark correlations in baryons on the lattice with overlap quarks: We evaluate baryon wave functions in both the Coulomb and Landau gauge in\nlattice QCD. These are constructed from quark propagators calculated with the\noverlap Dirac operator on quenched gauge configurations at beta = 6. By\ncomparing baryon states that differ in their diquark content, we find evidence\nfor enhanced correlation in the scalar diquark channel, as favored by quark\nmodels. We also summarize earlier results for diquark masses in the Landau\ngauge, casting them in a form more easily compared with subsequent studies.",
        "positive": "Expanding the Interpolator Basis in the Variational Method to Explicitly\n  Account for Backward Running States: In this paper, I show that backward (in time) running states can be\nexplicitly accounted for by expanding the interpolator basis in the variational\nmethod in lattice QCD. The backward running states can then be removed by\nchoosing an appropriate linear combination of interpolators, which improves the\nsignal significantly. The proof of principle, which also makes use of the\nTime-Shift Trick (Generalized Pencil-of-Functions method), will be delivered at\nan example on a $64^4$ lattice close to the physical pion mass."
    },
    {
        "anchor": "Finite temperature QED3 with light fermions: Non-compact QED3 is simulated both in the quenched and unquenched cases. In\nparticular, we investigate the restoration of chiral symmetry at finite\ntemperature. We also compute the zero temperature spectrum of the theory,\nincluding (in the quenched case) the dynamical fermion mass. From these two set\nof data, one can obtain estimates for the ratio of the mass gap to the critical\ntemperature, of particular interest for applications to high-Tc\nsuperconductivity.",
        "positive": "Generalized parton distributions from domain wall valence quarks and\n  staggered sea quarks: Moments of the generalized parton distributions of the nucleon, calculated\nwith a mixed action of domain wall valence quarks and asqtad staggered sea\nquarks, are presented for pion masses extending down to 359 MeV. Results for\nthe moments of the unpolarized, helicity, and transversity distributions are\ngiven and compared to the available experimental measurements. Additionally, a\nselection of the generalized form factors are shown and the implications for\nthe spin decomposition and transverse structure of the nucleon are discussed.\nParticular emphasis is placed on understanding systematic errors in the lattice\ncalculation and exploring a variety of chiral extrapolations."
    },
    {
        "anchor": "Lattice baryon spectroscopy with multi-particle interpolators: In 2 + 1 flavour lattice QCD the spectrum of the nucleon is presented for\nboth parities using local meson-baryon type interpolating fields in addition to\nthe standard three-quark nucleon interpolators. The role of local five-quark\noperators in extracting the nucleon excited state spectrum via correlation\nmatrix techniques is explored on dynamical gauge fields with $m_\\pi$ = 293 MeV,\nleading to the observation of a state consistent with the S-wave $N\\pi$\nscattering threshold in the negative-parity sector. Furthermore, the robustness\nof the variational technique is examined by studying the spectrum on a variety\nof operator bases. Fitting a single-state ansatz to the eigenstate-projected\ncorrelators provides robust energies for the low-lying spectrum that are\nessentially invariant despite being extracted from qualitatively different\nbases.",
        "positive": "Topological critical slowing down: variations on a toy model: Numerical simulations of lattice quantum field theories whose continuum\ncounterparts possess classical solutions with non-trivial topology face a\nsevere critical slowing down as the continuum limit is approached. Standard\nMonte-Carlo algorithms develop a loss of ergodicity, with the system remaining\nfrozen in configurations with fixed topology. We analyze the problem in a\nsimple toy model, consisting of the path integral formulation of a quantum\nmechanical particle constrained to move on a circumference. More specifically,\nwe implement for this toy model various techniques which have been proposed to\nsolve or alleviate the problem for more complex systems, like non-abelian gauge\ntheories, and compare them both in the regime of low temperature and in that of\nvery high temperature. Among the various techniques, we consider also a new\nalgorithm which completely solves the freezing problem, but unfortunately is\nspecifically tailored for this particular model and not easily exportable to\nmore complex systems."
    },
    {
        "anchor": "The Polyakov loop models in the large N limit: Correlation function and\n  screening masses: We explore the 't Hooft-Veneziano limit of the Polyakov loop models at finite\nbaryon chemical potential. Using methods developed by us earlier we calculate\nthe two- and $N$-point correlation functions of the Polyakov loops. This gives\na possibility to compute the various potentials in the confinement phase and to\nderive the screening masses outside the confinement region. In particular, we\nestablish the existence of complex masses and an oscillating decay of\ncorrelations in a certain range of parameters. Furthermore, it is shown that\nthe calculation of the $N$-point correlation function in the confinement phase\nreduces to the geometric median problem. This leads to a large $N$ analog of\nthe $Y$ law for the baryon potential.",
        "positive": "Optimized Distillation Profiles for Heavy-Light Spectroscopy: It has been demonstrated that distillation profiles can be employed to build\noptimized quarkonium interpolators for spectroscopy calculations in lattice\nQCD. We test their usefulness for heavy-light systems on (3+1)-flavor ensembles\nwith mass-degenerate light and a charm quark in the sea in preparation for a\nfuture $D\\bar{D}$-scattering analysis. The additional cost of light inversions\nnaturally leads to the question if knowledge of optimal profiles can be used to\navoid superfluous computations. We show such optimal profiles for different\nlattice sizes and pion masses and discuss general trends. Furthermore, we\ndiscuss the handling of momenta in this framework."
    },
    {
        "anchor": "Exotic static 3-body potentials: We study exotic static 3-body potentials, utilizing generalized Wilson Loops\nin SU(3) lattice QCD. For the quark-antiquark-gluon techniques we address the\nangles of 0, 45, 60, 90, 120, 135 and 180 degrees, between the quark-gluon and\nthe antiquark-gluon segments. We calculate the form of the static potential and\ndiscuss whether, or not, two-body interactions exist between the three\ndifferent bodies, and study the existence of repulsion between the strings. We\nalso perform a first study of the interactions in the system of three gluon.",
        "positive": "A lattice study of the pentaquark states: We present a study of the pentaquark system in quenched lattice QCD using\ndiquark-diquark and kaon-nucleon local and smeared interpolating fields. We\nexamine the volume dependence of the spectral weights of local correlators on\nlattices of size $16^3\\times 32$, $24^3\\times32$ and $32^3\\times 64$ at\n$\\beta=6.0$. We find that a reliable evaluation of the volume dependence of the\nspectral weights requires accurate determination of the correlators at large\ntime separations. Our main result from the spectral weight analysis in the\npentaquark system is that within our variational basis and statistics we can\nnot exclude a pentaquark resonance. However our data also do not allow a clear\nidentification of a pentaquark state since only the spectral weights of the\nlowest state can be determined to sufficient accuracy to test for volume\ndependence. In the negative parity channel the mass extracted for this state is\nvery close to the KN threshold whereas in the positive parity channel is about\n60% above."
    },
    {
        "anchor": "Quarkonium Spectral Function from Anisotropic Lattice: We discuss the behavior of charmonia and bottomonia correlators and spectral\nfunctions above the deconfinement temperature and determine melting\ntemperatures for different mesonic states.",
        "positive": "A complete non-perturbative renormalization prescription for quasi-PDFs: In this work we present, for the first time, the non-perturbative\nrenormalization for the unpolarized, helicity and transversity quasi-PDFs, in\nan RI' scheme. The proposed prescription addresses simultaneously all aspects\nof renormalization: logarithmic divergences, finite renormalization as well as\nthe linear divergence which is present in the matrix elements of fermion\noperators with Wilson lines. Furthermore, for the case of the unpolarized\nquasi-PDFs, we describe how to eliminate the unwanted mixing with the twist-3\nscalar operator. We utilize perturbation theory for the one-loop conversion\nfactor that brings the renormalization functions to the MS-scheme at a scale of\n2 GeV. We also explain how to improve the estimates on the renormalization\nfunctions by eliminating lattice artifacts. The latter can be computed in\none-loop perturbation theory and to all orders in the lattice spacing. We apply\nthe methodology for the renormalization to an ensemble of twisted mass fermions\nwith Nf=2+1+1 dynamical light quarks, and a pion mass of around 375 MeV."
    },
    {
        "anchor": "Local gauge invariance of free fields: It is noted that, in contrast to widespread believes, free fields do not only\nallow for global, but also for local gauge invariance.",
        "positive": "Exploring the spectrum of QCD using a space-time lattice: Some past and ongoing explorations of the spectrum of QCD using Monte Carlo\nsimulations on a space-time lattice are described. Glueball masses in the\npure-gauge theory are reviewed, and the energies of gluonic excitations in the\npresence of a static quark-antiquark pair are discussed. Current efforts to\ncompute the baryon spectrum using extended three-quark operators are also\npresented, emphasizing the need to use irreducible representations of the cubic\npoint group to identify spin quantum numbers in the continuum limit."
    },
    {
        "anchor": "Period of K System Generator of Pseudorandom Numbers: We analyze the structure of the periodic trajectories of the matrix generator\nof pseudorandom numbers which has been proposed earlier. The structure of the\nperiodic trajectories becomes more transparent when the rational sublattice\ncoincides with the Galois field $GF[p]$. We are able to compute the period of\nthe trajectories as a function of $p$ and the dimension of the matrix $d$.",
        "positive": "Proper static potential in classical lattice gauge theory at finite T: We compute the proper real-time interaction potential between a static quark\nand antiquark in classical lattice gauge theory at finite temperature. Our\ncentral result is the determination of the screened real-part of this\npotential, and we reconfirm the presence of an imaginary part. The real part is\nintimately related to the back-reaction of the static sources onto the gauge\nfields, incorporated via Gauss's law. Differences in the treatment of static\nsources in quantum and classical lattice gauge theory are discussed."
    },
    {
        "anchor": "Perturbative improvement of SU(2) gauge theory with two Wilson fermions\n  in the adjoint representation: We present a perturbative calculation of the improvement coefficients of\nSU(2) gauge theory with adjoint representation Wilson-clover fermions and using\nSchrodinger functional boundary conditions. The computation of the boundary\nimprovement terms is necessary for the full O(a) improvement. With two flavours\nof adjoint representation fermions this theory is called Minimal Walking\nTechnicolor model.",
        "positive": "Moments of Nucleon Light Cone Quark Distributions Calculated in Full\n  Lattice QCD: Moments of the quark density, helicity, and transversity distributions are\ncalculated in unquenched lattice QCD. Calculations of proton matrix elements of\noperators corresponding to these moments through the operator product expansion\nhave been performed on $16^3 \\times 32$ lattices for Wilson fermions at $\\beta\n= 5.6$ using configurations from the SESAM collaboration and at $\\beta = 5.5$\nusing configurations from SCRI. One-loop perturbative renormalization\ncorrections are included. At quark masses accessible in present calculations,\nthere is no statistically significant difference between quenched and full QCD\nresults, indicating that the contributions of quark-antiquark excitations from\nthe Dirac Sea are small. Close agreement between calculations with cooled\nconfigurations containing essentially only instantons and the full gluon\nconfigurations indicates that quark zero modes associated with instantons play\na dominant role. Naive linear extrapolation of the full QCD calculation to the\nphysical pion mass yields results inconsistent with experiment. Extrapolation\nto the chiral limit including the physics of the pion cloud can resolve this\ndiscrepancy and the requirements for a definitive chiral extrapolation are\ndescribed."
    },
    {
        "anchor": "Study on Lambda(1405) in the flavor SU(3) limit in the HAL QCD method: We study interactions between the S-wave octet pseudo-scalar (PS) meson and\noctet baryon in the flavor SU(3) limit using the HAL QCD method at the PS meson\nmass $m_M\\approx 670~\\textrm{MeV}$. We focus on the singlet and two octet\nchannels, where the poles corresponding to $\\Lambda(1405)$ have been predicted\nin the chiral unitary model. For calculations with $\\Lambda$-baryon source\noperators with zero momentum, we employ the conventional stochastic calculation\ncombined with the covariant-approximation averaging to calculate the all-to-all\npropagators. Due to a zero of the R-correlator (a kind of wave function), the\nleading order (LO) potential obtained by the single channel analysis has a\nsingular point in all channels, which makes it difficult to obtain reliable\nbinding energies. To overcome this problem, we take a linear combination of two\noctet R-correlators with a relative weight such that it does not cross zero, as\ntwo octet channels are suggested to couple to the same low-energy states with\ndifferent weights. The potential calculated from such the linear combination\nshows strong attraction without singularities, though its shape depends on the\nrelative weight. Our estimation for the binding energy in the octet channel is\n$E^{8_{s(a)}}_{\\textrm{bind}}=163(7)(^{+16} _{-64})~\\textrm{MeV}$, which is\nconsistent with 156(8) MeV estimated from the two-point correlation function\nwithin errors.",
        "positive": "Tetraquarks and pentaquarks in lattice QCD with light and heavy quarks: We review how lattice QCD can contribute to the prediction and the\ncomprehension of tetraquarks, pentaquarks and related exotic hadrons, with at\nleast one heavy quark. We include all families of exotic hadrons, except for\nthe quarkless glueballs and the hexaquarks which are related to nuclear\nphysics.\n  Since the discovery of quarks and the development of the QCD theory, there\nhas been a large interest in exotic hadrons, initiated by the tetraquark models\ndeveloped by Jaffe in 1977. Lattice QCD, being a first principle approach to\nsolve non-perturbative QCD, has been crucial not only to compute precise\nresults, but also to inspire research in hadronic physics.\n  In the new millennium, this interest exploded with several experimental\ndiscoveries of tetraquark and pentaquark resonances with heavy quarks, starting\nwith the Zc and Zb. Lattice QCD has not yet been able to comprehend this Z\nclass of tetraquarks, and is developing new methods to determine their masses,\ndecay widths and decay processes.\n  The interest in tetraquarks was also fuelled by the lattice QCD prediction of\na second class of tetraquarks such as the Tbb, boundstates in the sense of\nhaving no strong decays. Recently, the Tcc tetraquark, first predicted with\nquark models in 1982 by Richard et al, was observed experimentally. We expect\nthe lattice QCD community will be able to explore this T class of tetraquarks\nin more detail and with very precise results.\n  We report on all the different direct and indirect approaches that lattice\nQCD, with more focus on tetraquarks, has been employing to study exotic hadrons\nwith at least one heavy quark. We also briefly review the experimental progress\nin observing tetraquarks and pentaquarks, and some of the theoretical paradigms\nof tetraquarks, including three different types of mechanisms (diquark,\nmolecular and s pole), comparing them with the results of lattice QCD."
    },
    {
        "anchor": "Semileptonic Kaon Decay in Staggered Chiral Perturbation Theory: The determination of $\\vert V_{us}\\vert$ from kaon semileptonic decays\nrequires the value of the form factor $f_+(q^2=0)$, which can be calculated\nprecisely on the lattice. We provide the one-loop partially quenched staggered\nchiral perturbation theory expressions that may be employed to analyze\nstaggered simulations of $f_+(q^2)$ with three light flavors. We consider both\nthe case of a mixed action, where the valence and sea sectors have different\nstaggered actions, and the standard case where these actions are the same. The\nmomentum transfer $q^2$ of the form factor is allowed to have an arbitrary\nvalue. We give results for the generic situation where the $u$, $d$, and $s$\nquark masses are all different, $N_f=1+1+1$, and for the isospin limit,\n$N_f=2+1$. The expression we obtain for $f_+(q^2)$ is independent of the mass\nof the (valence) spectator quark. In the limit of vanishing lattice spacing,\nour results reduce to the one-loop continuum partially quenched expression for\n$f_+(q^2)$, which has not previously been reported in the literature for the\n$N_f=1+1+1$ case. Our expressions have already been used in staggered lattice\nanalyses of $f_+(0)$, and should prove useful in future calculations as well.",
        "positive": "Constraints on charm-anticharm asymmetry in the nucleon from lattice QCD: We present the first lattice QCD calculation of the charm quark contribution\nto the nucleon electromagnetic form factors $G^c_{E,M}(Q^2)$ in the momentum\ntransfer range $0\\leq Q^2 \\leq 1.4$ $\\rm GeV^2$. The quark mass dependence,\nfinite lattice spacing and volume corrections are taken into account\nsimultaneously based on the calculation on three gauge ensembles including one\nat the physical pion mass. The nonzero value of the charm magnetic moment\n$\\mu^c_M=-0.00127(38)_{\\rm stat}(5)_{\\rm sys}$, as well as the Pauli form\nfactor, reflects a nontrivial role of the charm sea in the nucleon spin\nstructure. The nonzero $G^c_{E}(Q^2)$ indicates the existence of a nonvanishing\nasymmetric charm-anticharm sea in the nucleon. Performing a nonperturbative\nanalysis based on holographic QCD and the generalized Veneziano model, we study\nthe constraints on the $[c(x)-\\bar{c}(x)]$ distribution from the lattice QCD\nresults presented here. Our results provide complementary information and\nmotivation for more detailed studies of physical observables that are sensitive\nto intrinsic charm and for future global analyses of parton distributions\nincluding asymmetric charm-anticharm distribution."
    },
    {
        "anchor": "More effects of Dirac low-mode removal: In previous studies we have shown that hadrons, except for a pion, survive\nthe removal of the lowest lying Dirac eigenmodes from the valence quark\npropagators. The low-modes are tied to the dynamical breaking of chiral\nsymmetry and we found chiral symmetry to be restored by means of matching\nmasses of chiral partners, like, e.g., the vector and axial vector currents.\nHere we investigate the influence of removing the lowest part of the Dirac\nspectrum on the locality of the Dirac operator. Moreover, we analyze the\ninfluence of low-mode truncation on the quark momenta and thereupon on the\nhadron spectrum and, finally, introduce a reweighting scheme to extend the\ntruncation to the sea quark sector.",
        "positive": "Dynamics of the $O(4)$ critical point in QCD: critical pions and\n  diffusion in Model G: We present a detailed study of the finite momentum dynamics of the $O(4)$\ncritical point of QCD, which lies in the dynamic universality class of Model G.\nThe critical scaling of the model is analyzed in multiple dynamical channels.\nFor instance, the finite momentum analysis allows us to precisely extract the\npion dispersion curve below the critical point. The pion velocity is in\nstriking agreement with the predictions relation and static universality. The\npion damping rate and velocity are both consistent with the dynamical critical\nexponent $\\zeta = 3/2$ of Model G. Similarly, although the critical amplitude\nfor the diffusion coefficient of the conserved $O(4)$ charges is small, it is\nclearly visible both in the restored phase and with finite explicit symmetry\nbreaking, and its dynamical scaling is again consistent with $\\zeta=3/2$. We\ndetermine a new set of universal dynamical critical amplitude ratios relating\nthe diffusion coefficient to a suitably defined order parameter relaxation\ntime. We also show that in a finite volume simulation, the chiral condensate\ndiffuses on the coset manifold in a manner consistent with dynamical scaling,\nand with a diffusion coefficient that is determined by the transport\ncoefficients of hydrodynamic pions. Finally, the amplitude ratios (together\nwith other non-universal amplitudes also reported here) compile all relevant\ninformation for further studies of Model G both in and out of equilibrium."
    },
    {
        "anchor": "PJLZ--gauge fixing approach in SU(2) lattice gauge theory: We study the SU(2) gauge theory with the interpolating gauge {\\it a la}\nParrinello--Jona-Lasinio--Zwanziger (PJLZ) with the gauge fixing functional\n$F=\\sum_{x\\mu} {1/2}\\tr (U_{x\\mu}\\sigma_3U_{x\\mu}^{\\dagger}\\sigma_3)$. We find\na strong indication of the non--analiticity with respect to the interpolating\nparameter $\\lambda$ at $\\lambda_c \\sim 0.8$.",
        "positive": "Lattice supersymmetry in 1D with two supercharges: A consistent formulation of a fully supersymmetric theory on the lattice has\nbeen a long standing challenge. In recent years there has been a renewed\ninterest on this problem with different approaches. At the basis of the\nformulation we present in the following there is the Dirac-Kahler twisting\nprocedure, which was proposed in the continuum for a number of theories,\nincluding N=4 SUSY in four dimensions. Following the formalism developed in\nrecent papers, an exact supersymmetric theory with two supercharges on a one\ndimensional lattice is realized using a matrix-based model. The matrix\nstructure is obtained from the shift and clock matrices used in two dimensional\nnon-commutative field theories. The matrix structure reproduces on a one\ndimensional lattice the expected modified Leibniz rule. Recent claims of\ninconsistency of the formalism are discussed and shown not to be relevant."
    },
    {
        "anchor": "The Use of the Monte Carlo Hamiltonian: In order to solve quantum field theory in a non-perturbative way, Lagrangian\nlattice simulations have been very successful. Here we discuss a recently\nproposed alternative Hamiltonian lattice formulation - the Monte Carlo\nHamiltonian. In order to show its working in the case of the scalar\n$\\Phi^{4}_{1+1}$ model, we have computed thermodynamic functions like free\nenergy, average energy, entropy and specific heat. We find good agreement\nbetween the results from the Monte Carlo Hamiltonian and standard Lagrangian\nlattice computations. However, the Monte Carlo Hamiltonian results show less\nfluctuations under variation of temperature. We address properties of the MC\nHamiltonian, like a finite temperature window, and scaling properties. Also we\ndiscuss possible future applications - like quantum chaos in many-body systems,\nthe non-perturbative computation of wave functions of elementary particles, as\nwell as scattering amplitudes in high energy physics.",
        "positive": "The phase structure of pure Regge gravity: We examine the phase structure of pure Regge gravity in four dimensions and\ncompare our Monte Carlo results with $Z_2$-link Regge-theory as well as with\nanother formulation of lattice gravity derived from group theoretical\nconsiderations. Within all three models we find an extension of the\nwell-defined phase to negative gravitational coupling and a new phase\ntransition. In contrast to the well-known transition at positive coupling there\nis evidence for a continuous phase transition which might be essential for a\npossible continuum limit."
    },
    {
        "anchor": "Calculation of Non-Leptonic Kaon Decay Amplitudes from $K\\to\u03c0$ Matrix\n  Elements in Quenched Domain-Wall QCD: We explore application of the domain wall fermion formalism of lattice QCD to\ncalculate the $K\\to\\pi\\pi$ decay amplitudes in terms of the $K\\to\\pi$ and $K\\to\n0$ hadronic matrix elements through relations derived in chiral perturbation\ntheory. Numerical simulations are carried out in quenched QCD using domain-wall\nfermion action for quarks and an RG-improved gauge action for gluons on a\n$16^3\\times 32\\times 16$ and $24^3\\times 32\\times 16$ lattice at $\\beta=2.6$\ncorresponding to the lattice spacing $1/a\\approx 2$GeV. Quark loop contractions\nwhich appear in Penguin diagrams are calculated by the random noise method, and\nthe $\\Delta I=1/2$ matrix elements which require subtractions with the quark\nloop contractions are obtained with a statistical accuracy of about 10%. We\nconfirm the chiral properties required of the $K\\to\\pi$ matrix elements.\nMatching the lattice matrix elements to those in the continuum at $\\mu=1/a$\nusing the perturbative renormalization factor to one loop order, and running to\nthe scale $\\mu=m_c=1.3$ GeV with the renormalization group for $N_f=3$ flavors,\nwe calculate all the matrix elements needed for the decay amplitudes. With\nthese matrix elements, the $\\Delta I=3/2$ decay amplitude shows a good\nagreement with experiment in the chiral limit. The $\\Delta I=1/2$ amplitude, on\nthe other hand, is about 50--60% of the experimental one even after chiral\nextrapolation. In view ofthe insufficient enhancement of the $\\Delta I=1/2$\ncontribution, we employ the experimental values for the real parts of the decay\namplitudes in our calculation of $\\epsilon'/\\epsilon$. We find that the $\\Delta\nI=3/2$ contribution is larger than the $\\Delta I=1/2$ contribution so that\n$\\epsilon'/\\epsilon$ is negative and has a magnitude of order $10^{-4}$.\nPossible reasons for these unsatisfactory results are discussed.",
        "positive": "Noncompact chiral U(1) gauge theories on the lattice: A new, adiabatic phase choice is adopted for the overlap in the case of an\ninfinite volume, noncompact abelian chiral gauge theory. This gauge choice\nobeys the same symmetries as the Brillouin-Wigner (BW) phase choice, and, in\naddition, produces a Wess-Zumino functional that is linear in the gauge\nvariables on the lattice. As a result, there are no gauge violations on the\ntrivial orbit in all theories, consistent and covariant anomalies are simply\nrelated and Berry's curvature now appears as a Schwinger term. The adiabatic\nphase choice can be further improved to produce a perfect phase choice, with a\nlattice Wess-Zumino functional that is just as simple as the one in continuum.\nWhen perturbative anomalies cancel, gauge invariance in the fermionic sector is\nfully restored. The lattice effective action describing an anomalous abelian\ngauge theory has an explicit form, close to one analyzed in the past in a\nperturbative continuum framework."
    },
    {
        "anchor": "Infrared fixed point of the SU(3) gauge theory with $N_f = 10$ flavors: We use lattice simulations and the continuous renormalization-group method,\nbased on the gradient flow, to calculate the $\\beta$ function and anomalous\ndimensions of the SU(3) gauge theory with $N_f=10$ flavors of fermions in the\nfundamental representation. We employ several improvements to extend the range\nof available renormalized couplings, including the addition of heavy\nPauli-Villars bosons to reduce cutoff effects and the combination of a range of\ngradient flow transformations. While in the weak coupling regime our result is\nconsistent with those of earlier studies, our techniques allow us to study the\nsystem at much stronger couplings than previously possible. We find that the\nrenormalization group $\\beta$ function develops a zero, corresponding to an\ninfrared-stable fixed point, at gradient-flow coupling $g^2=15.0(5)$. We also\ndetermine the mass and tensor anomalous dimensions: At the fixed point we find\n$\\gamma_m\\simeq0.6$, suggesting that this system might be deep inside the\nconformal window.",
        "positive": "Searching for the $X(3872)$ and $Z_c^+(3900)$ on HISQ lattices: We present preliminary simulation results for the I = 0 charmonium state\n$X(3872)(1^{++})$ and the I = 1 charmonium state $Z_c^+(3900)(1^{+-})$. The\nstudy is performed on gauge field configurations with 2+1+1 flavors of highly\nimproved staggered sea quarks (HISQ) with clover (Fermilab interpretation)\ncharm quarks and HISQ light valence quarks. Since the $X(3872)$ lies very close\nto the open charm $D \\bar D^*$ threshold, we use a combination of $\\bar c c$\nand $D \\bar D^* + \\bar D D^*$ interpolating operators. For the $Z_c^+(3900)$ we\nuse a combination of $J/\\psi \\pi$ and $D \\bar D^* + \\bar D D^*$ channels. This\nis the first such study with HISQ sea quarks and light valence quarks. To this\nend, we describe a variational method for treating staggered quarks that\nincorporates both oscillating and non-oscillating components."
    },
    {
        "anchor": "The spatial string tension and dimensional reduction in QCD: The spatial string tension for 3+1 dimensional QCD at finite temperature is\nmeasured. The gauge configurations we re generated with two light and one\nheavier strange quark on lattices of size $16^3 4$ and $24^3 6$. This spatial\nstring tension is compared with the string tension of the 3 dimensional pure\ngauge theory together with the temperature dependent 2-loop running coupling.\nFurther comparison is made with predictions from dimensionally reduced\neffective theories.",
        "positive": "Lattice determination of fBd, fBs, and xi: In this talk I summarize the recent lattice determinations of the decay\nconstants and of the bag parameters of the heavy-light and heavy-strange\nneutral mesons."
    },
    {
        "anchor": "Topological charge and cooling scales in pure SU(2) lattice gauge theory: Using Monte Carlo simulations with overrelaxation, we have equilibrated\nlattices up to $\\beta=2.928$, size $60^4$, for pure SU(2) lattice gauge theory\nwith the Wilson action. We calculate topological charges with the standard\ncooling method and find that they become more reliable with increasing $\\beta$\nvalues and lattice sizes. Continuum limit estimates of the topological\nsusceptibility $\\chi$ are obtained of which we favor\n$\\chi^{1/4}/T_c=0.643\\,(12)$, where $T_c$ is the SU(2) deconfinement\ntemperature. Differences between cooling length scales in different topological\nsectors turn out to be too small to be detectable within our statistical\nerrors.",
        "positive": "Symmetries of temporal correlators and the nature of hot QCD: The temperature of the chiral restoration phase transition at 130 MeV as well\nas the temperature of the center symmetry (\"deconfinement\") phase transition in\na pure glue theory at 300 MeV are two independent temperatures and their\ninterplay determines a structure of different regimes of hot QCD. Given a\nchiral spin symmetry of the color charge and of the chromoelectric interaction\nwe can conclude from observed symmetries of spatial and temporal correlators of\nN_F=2 QCD with domain wall Dirac operator at physical quark masses that above\nthe chiral symmetry restoration crossover around T_pc but below rougly 3T_pc\nthere should exist an intermediate regime (the stringy fluid) of hot QCD that\nis characterized by approximate chiral spin symmetry and where degrees of\nfreedom are chirally symmetric quarks bound into color singlet objects by the\nchromoelectric field. Above this intermediate regime the color charge and the\nchromoelectric field are Debye screened and one observes a transition to QGP\nwith magnetic confinement."
    },
    {
        "anchor": "Lattice gluodynamics computation of Landau-gauge Green's functions in\n  the deep infrared: We present recent results for the Landau-gauge gluon and ghost propagators in\nSU(3) lattice gluodynamics obtained on a sequence of lattices with linear\nextension ranging from L=64 to L=96 at $\\beta = 5.70$, thus reaching \"deep\ninfrared\" momenta down to 75 MeV. Our gauge-fixing procedure essentially uses a\nsimulated annealing technique which allows us to reach gauge-functional values\ncloser to the global maxima than standard approaches do. Our results are\nconsistent with the so-called decoupling solutions found for Dyson-Schwinger\nand functional renormalization group equations.",
        "positive": "SU(2) finite temperature phase transition and Michael sum rules: We studied the finite temperature phase transition of SU(2) gauge theory on\nfour-dimensional Euclidean lattices by Monte Carlo simulations, and measured\nthe flux distributions of a $q\\bar q$ pair in both confined and unconfined\nphases. We reviewed and generalized Michael sum rules to include finite\ntemperature effects. To compare our flux data with predictions of Michael sum\nrules, we studied the behavior of string tension with temperature. Our data\nagree well with the generalized sum rules."
    },
    {
        "anchor": "Hadronic light-by-light scattering in the anomalous magnetic moment of\n  the muon: Hadronic light-by-light scattering in the anomalous magnetic moment of the\nmuon $a_\\mu$ is one of two hadronic effects limiting the precision of the\nStandard Model prediction for this precision observable, and hence the\nnew-physics discovery potential of direct experimental determinations of\n$a_\\mu$. In this contribution, we report on recent progress in the calculation\nof this effect achieved both via dispersive and lattice QCD methods.",
        "positive": "The Degrees of Freedom in Hot Quenched QCD: In quenched QCD, on lattices with $\\nt=4$, the absence of a pole in the\npseudoscalar meson channel for $T>T_c$ is demonstrated. A set of effective\n4-fermi couplings is extracted. It is observed that this coupling is small in\nthe vector channel for all $T>T_c$, but not in the pseudoscalar channel. The\ntemperature dependence of hadronic parameters below \\tc{} is found to be small.\nNOTE: Latex source, no figures, needs espcrc2.sty from hep-lat macros."
    },
    {
        "anchor": "A note on the Loop Formula for the fermionic determinant: A formula expressing the fermionic determinant as an infinite product of\nsmaller determinants is derived and discussed. These smaller determinants are\nof a fixed size, independent of the size of the lattice and are indexed by\nloops of increasing length.",
        "positive": "Three-Dimensional Quantum Gravity Coupled to Gauge Fields: We show how to simulate U(1) gauge fields coupled to three-dimensional\nquantum gravity and then examine the phase diagram of this system. Quenched\nmean field theory suggests that a transition separates confined and deconfined\nphases (for the gauge matter) in both the negative curvature phase and the\npositive curvature phase of the quantum gravity, but numerical simulations find\nno evidence for such transitions."
    },
    {
        "anchor": "Lattice QCD: a critical status report: The substantial progress that has been achieved in lattice QCD in the last\nyears is pointed out. I compare the simulation cost and systematic effects of\nseveral lattice QCD formulations and discuss a number of topics such as lattice\nspacing scaling, applications of chiral perturbation theory, non-perturbative\nrenormalization and finite volume effects. Additionally, the importance of\ndemonstrating universality is emphasized.",
        "positive": "Nonperturbative improvement of SU(2) lattice gauge theory with adjoint\n  or fundamental flavors: SU(2) gauge theory with two fermions transforming under the adjoint\nrepresentation may appear conformal or almost conformal in the infrared, and is\none of the candidate theories for building models for technicolor. Early\nlattice Monte Carlo studies of this model have used unimproved Wilson fermion\nformulation, which can be expected to have large lattice cutoff effects. In\nthis paper we present the calculation of the O(a) improved lattice\nWilson-clover action of the theory. The Sheikholeslami-Wohlert coefficient has\nbeen determined non-perturbatively, and various boundary improvement terms,\nneeded for the Schroedinger functional formalism, have been calculated in\nperturbation theory. For comparison, we have also determined the improvement\ncoefficients for SU(2) gauge theory with two fundamental representation\nfermions. The calculation paves way for more accurate lattice Monte Carlo\nanalyses of the theory in the future."
    },
    {
        "anchor": "3d quantum gravity coupled to matter: We investigate the phase structure of three-dimensional quantum gravity\ncoupled to an Ising spin system by means of numerical simulations. The quantum\ngravity part is modelled by the summation over random simplicial manifolds, and\nthe Ising spins are located in the center of the tetrahedra, which constitute\nthe building blocks of the piecewise linear manifold. We find that the coupling\nbetween spin and geometry is weak away from the critical point of the Ising\nmodel. At the critical point there is clear coupling, which however does not\nseem to change the first order transition between the ``hot'' and ``cold''\nphase of three dimensional simplicial quantum gravity observed earlier.",
        "positive": "Meson Spectral Functions at finite Temperature: The Maximum Entropy Method provides a Bayesian approach to reconstruct the\nspectral functions from discrete points in Euclidean time. The applicability of\nthe approach at finite temperature is probed with the thermal meson correlation\nfunction. Furthermore the influence of fuzzing/smearing techniques on the\nspectral shape is investigated. We present first results for meson spectral\nfunctions at several temperatures below and above $T_c$. The correlation\nfunctions were obtained from quenched calculations with Clover fermions on\nlarge isotropic lattices of the size $(24-64)^3 \\times 16$. We compare the\nresulting pole masses with the ones obtained from standard 2-exponential fits\nof spatial and temporal correlation functions at finite temperature and in the\nvacuum. The deviation of the meson spectral functions from free spectral\nfunctions is examined above the critical temperature."
    },
    {
        "anchor": "Chemical potential dependence of the endpoint of first-order phase\n  transition in heavy-quark region of finite-temperature lattice QCD: We determine the location of the critical point where the first-order\ndeconfining transition in the heavy-quark region turns into a crossover in\nfinite-temperature and density lattice QCD with 2+1 flavors of Wilson quarks.\nCombining a hopping parameter expansion (HPE) of the quark determinant with a\nreweighting method, we evaluate the chemical potential dependence of the\ncritical point. By systematically calculating the coefficients of the hopping\nparameter expansion up to a high order of HPE at finite chemical potential, we\nfind that the higher order terms are strongly correlated with the Polyakov\nloop, which is the leading-order term, on each configuration. Moreover, their\ncomplex phases themselves, which are important at finite density, are also\nfound to be strongly correlated with the complex phase of the Polyakov loop.\nUsing this property, we develop a method for estimating the critical point\nincorporating high-order terms from calculations with only low-order terms. We\nreport that the first-order phase transition region in the heavy-quark region\nbecomes narrower exponentially with increasing the chemical potential. Since\nthe hopping parameter of the critical point decreases exponentially as the\ndensity increases, the sign problem does not become serious even when the\ndensity increases, and critical points can be evaluated up to high densities.",
        "positive": "First results of ETMC simulations with Nf=2+1+1 maximally twisted mass\n  fermions: We present first results from runs performed with Nf=2+1+1 flavours of\ndynamical twisted mass fermions at maximal twist: a degenerate light doublet\nand a mass split heavy doublet. An overview of the input parameters and tuning\nstatus of our ensembles is given, together with a comparison with results\nobtained with Nf=2 flavours. The problem of extracting the mass of the K- and\nD-mesons is discussed, and the tuning of the strange and charm quark masses\nexamined. Finally we compare two methods of extracting the lattice spacings to\ncheck the consistency of our data and we present some first results of ChiPT\nfits in the light meson sector."
    },
    {
        "anchor": "Gauge invariant properties of Abelian monopoles: Using a renormalization group motivated smoothing technique, we investigate\nthe large scale structure of lattice configurations at finite temperature,\nconcentrating on Abelian monopoles identified in the maximally Abelian, the\nLaplacian Abelian, and the Polyakov gauge. Monopoles are mostly found in\nregions of large action and topological charge, rather independent of the gauge\nchosen to detect them. Gauge invariant properties around Abelian monopoles, the\nlocal non-Abelian action and topological density, are studied. We show that the\nlocal averages of these densities along the monopole trajectories are clearly\nabove the background, which supports the existence of monopoles as physical\nobjects. Characteristic changes of the vacuum structure at the deconfinement\ntransition can be attributed to the corresponding Abelian monopoles, to an\nextent that depends on the gauge chosen for Abelian projection. All three\nAbelian projections reproduce the full SU(2) string tension within 10 percent\nwhich is preserved by smoothing.",
        "positive": "Tetraquark operators in lattice QCD and exotic flavour states in the\n  charm sector: We present a general class of operators resembling compact tetraquarks which\nhave a range of colour-flavour-spin structures, transform irreducibly under the\nsymmetries of the lattice and respect other relevant symmetries. These\nconstructions are demonstrated in lattice QCD calculations with light quarks\ncorresponding to $m_\\pi =$ 391 MeV. Using the distillation framework,\ncorrelation functions involving large bases of meson-meson and tetraquark\noperators are computed in the isospin-1 hidden-charm and doubly-charmed\nsectors, and finite-volume spectra are extracted with the variational method.\nWe find the spectra are insensitive to the addition of tetraquark operators to\nthe bases of meson-meson operators. For the first time, through using diverse\nbases of meson-meson operators, the multiple energy levels associated with\nmeson-meson levels which would be degenerate in the non-interacting limit are\nextracted reliably. The number of energy levels in each spectrum is found to be\nequal to the number of expected non-interacting meson-meson levels in the\nenergy region considered and the majority of energies lie close to the\nnon-interacting levels. Therefore, there is no strong indication for any bound\nstate or narrow resonance in the channels we study."
    },
    {
        "anchor": "On the Logarithmic Triviality of Scalar Quantum Electrodynamics: Using finite size scaling and histogram methods we obtain numerical results\nfrom lattice simulations indicating the logarithmic triviality of scalar\nquantum electrodynamics, even when the bare gauge coupling is chosen large.\nSimulations of the non-compact formulation of the lattice abelian Higgs model\nwith fixed length scalar fields on $L^{4}$ lattices with $L$ ranging from $6$\nthrough $20$ indicate a line of second order critical points.\nFluctuation-induced first order transitions are ruled out. Runs of over ten\nmillion sweeps for each $L$ produce specific heat peaks which grow\nlogarithmically with $L$ and whose critical couplings shift with $L$ picking\nout a correlation length exponent of $0.50(5)$ consistent with mean field\ntheory. This behavior is qualitatively similar to that found in pure\n$\\lambda\\phi^{4}$.",
        "positive": "QCD phase diagram: overview of recent lattice results: Two parameters that have a strong influence on the finite temperature QCD\ntransition, and play an important role in various physical scenarios are the\nquark density and the external magnetic field. The effect of these parameters\non the thermal properties of QCD is discussed, and an overview of the latest\nlattice results is given."
    },
    {
        "anchor": "Fermionic Field Theory and Gauge Interactions on Random Lattices: Random-lattice fermions have been shown to be free of the doubling problem if\nthere are no interactions or interactions of a non-gauge nature. However, gauge\ninteractions impose stringent constraints as expressed by the Ward-Takahashi\nidentities which could revive the free-field suppressed doubler modes in loop\ndiagrams. After introducing a formulation for fermions on a new kind of random\nlattice, we compare random, naive and Wilson fermions in two dimensional\nAbelian background gauge theory. We show that the doublers are revived for\nrandom lattices in the continuum limit, while demonstrating that gauge\ninvariance plays the critical role in this revival. Some implications of the\npersistent doubling phenomenon on random lattices are also discussed.",
        "positive": "The neutral pion decay and the chiral anomaly on the lattice: We perform a lattice QCD calculation of the \\pi^0\\to\\gamma\\gamma transition\nform factor and the associated decay width. We use a Euclidean time integral of\nthe relevant three-point function to compute the decay amplitude for two-photon\nfinal state, which is a non-QCD state. We use the all-to-all quark propagator\ntechnique to carry out this integral as well as to include the disconnected\nquark diagram contributions. We execute the calculation using the overlap\nfermion formulation, which ensures the exact chiral symmetry on the lattice and\nproduces the chiral anomaly through the Jacobian of the chiral transformation.\nWe examine various sources of systematic effects except for possible\ndiscretization effect. Our final results for the form factor and the decay\nwidth reproduce the ABJ anomaly in the chiral limit and agree with the\nexperimental measurements at the physical pion mass with a precision of a few\npercent."
    },
    {
        "anchor": "Radiative corrections to decay amplitudes in lattice QCD: The precision of lattice QCD computations of many quantities has reached such\na precision that isospin-breaking corrections, including electromagnetism, must\nbe included if further progress is to be made in extracting fundamental\ninformation, such as the values of Cabibbo-Kobayashi-Maskawa matrix elements,\nfrom experimental measurements. We discuss the framework for including\nradiative corrections in leptonic and semileptonic decays of hadrons, including\nthe treatment of infrared divergences. We briefly review isospin breaking in\nleptonic decays and present the first numerical results for the ratio\n$\\Gamma(K_{\\mu2})/\\Gamma(\\pi_{\\mu2})$ in which these corrections have been\nincluded. We also discuss the additional theoretical issues which arise when\nincluding electromagnetic corrections to semileptonic decays, such as\n$K_{\\ell3}$ decays. The separate definition of strong isospin-breaking effects\nand those due to electromagnetism requires a convention. We define and advocate\nconventions based on hadronic schemes, in which a chosen set of hadronic\nquantities, hadronic masses for example, are set equal in QCD and in QCD+QED.\nThis is in contrast with schemes which have been largely used to date, in which\nthe renormalised $\\alpha_s(\\mu)$ and quark masses are set equal in QCD and in\nQCD+QED in some renormalisation scheme and at some scale $\\mu$.",
        "positive": "Quantum delocalization of strings with boundary action in Yang-Mills\n  theory: The width of the quantum delocalization of the QCD strings is investigated in\neffective string models beyond free Nambu-Goto approximation. We consider two\nLorentzian-invariant boundary-terms in the L\\\"uscher-Weisz string action in\naddition to self-interaction term equivalent to two loop order in the (NG)\nstring action. The geometrical terms which realize the possible rigidity of the\nQCD string is scrutinized as well. We perform the numerical analysis on the\n4-dim pure $SU(3)$ Yang-Mills lattice gauge theory at two temperature scales\nnear deconfinement point. The comparative study with this QCD string model\ntargets the width of the energy profile of a static quark-antiquark system for\ncolor sources separation $0.5 \\le R \\le 1.2$ fm. We find the inclusion of\nrigidity properties and symmetry effects of the boundary action into the string\nparadigm to reproduce a good match with the profile of the Mont-Carlo data of\nQCD flux-tube on this distance scale."
    },
    {
        "anchor": "QCDF90: A set of Fortran 90 modules for a high-level, efficient\n  implementation of QCD simulations: We present a complete set of Fortran 90 modules that can be used to write\nvery compact, efficient, and high level QCD programs. The modules define fields\n(gauge, fermi, generators, complex, and real fields) as abstract data types,\ntogether with simpler objects such as SU(3) matrices or color vectors.\nOverloaded operators are then defined to perform all possible operations\nbetween the fields that may be required in a QCD simulation. QCD programs\nwritten using these modules need not have cumbersome subroutines and can be\nvery simple and transparent. This is illustrated with two simple example\nprograms.",
        "positive": "Gluon propagator, triple gluon vertex and the QCD coupling constant: We study the UV-scaling of the flavorless gluon propagator in the Landau\ngauge in an energy window up to 9 GeV. Dominant hypercubic lattice artifacts\nare eliminated. A large set of renormalization schemes is used to test\nasymptotic scaling. We compare with our results obtained directly from the\ntriple gluon vertex. We end-up with \\Lambda_{\\bar{\\rm{MS}}} = 318(12)(5) MeV\nand 292(5)(15) MeV respectively for these two methods, compatible which each\nother but significantly above the Schrodinger method estimate."
    },
    {
        "anchor": "CLS 2+1 flavor simulations at physical light- and strange-quark masses: We report recent efforts by CLS to generate an ensemble with physical light-\nand strange-quark masses in a lattice volume of 192x96^3 at $\\beta=3.55$\ncorresponding to a lattice spacing of 0.064 fm. This ensemble is being\ngenerated as part of the CLS 2+1 flavor effort with improved Wilson fermions.\nOur simulations currently cover 5 lattice spacings ranging from 0.039 fm to\n0.086 fm at various pion masses along chiral trajectories with either the sum\nof the quark masses kept fixed, or with the strange-quark mass at the physical\nvalue. The current status of simulations is briefly reviewed, including a short\ndiscussion of measured autocorrelation times and of the main features of the\nsimulations. We then proceed to discuss the thermalization strategy employed\nfor the generation of the physical quark-mass ensemble and present first\nresults for some simple observables. Challenges encountered in the simulation\nare highlighted.",
        "positive": "New results from mixed-action lattice gauge theory: We extend and attempt to clarify recent results which showed possible\nproblems for universality for the gauge group SU(2). We suggest that the\npresence of artifacts actually distorts the mixed-coupling plane. This implies\nthat a separation of artifacts from physical quantities is intrinsically\ndifficult. We suggest what the nature of the resolution might be. Full results\nwill appear elsewhere."
    },
    {
        "anchor": "Strangeness at high temperatures: We use up to fourth order cumulants of net strangeness fluctuations and their\ncorrelations with net baryon number fluctuations to extract information on the\nstrange meson and baryon contribution to the low temperature hadron resonance\ngas, the dissolution of strange hadronic states in the crossover region of the\nQCD transition and the quasi-particle nature of strange quark contributions to\nthe high temperature quark-gluon plasma phase.",
        "positive": "SymEFT predictions for local fermion bilinears: Beyond spectral quantities, Symanzik Effective Theory (SymEFT) predictions of\nthe asymptotic lattice-spacing dependence require the inclusion of an\nadditional minimal basis of higher-dimensional operators for each local field\ninvolved in the matrix element of interest. Adding the proper bases for fermion\nbilinears of mass-dimension 3 allows to generalise previous predictions to\nmatrix elements of those bilinears. These results can be incorporated in\nans\\\"atze used in continuum extrapolations and should allow improved control of\nthe associated systematic uncertainties. Potential difficulties and pitfalls\nare being highlighted. The current work is limited to the use of Wilson or\nGinsparg-Wilson quarks in both sea and valence."
    },
    {
        "anchor": "Probing the singularities of the Landau-gauge gluon and ghost\n  propagators with rational approximants: We employ Pad\\'e approximants in the study of the analytic structure of the\nfour-dimensional $SU(2)$ Landau-gauge gluon and ghost propagators in the\ninfrared regime. The approximants, which are model independent, serve as\nfitting functions for the lattice data. We carefully propagate the\nuncertainties due to the fitting procedure, taking into account all possible\ncorrelations. For the gluon-propagator data, we confirm the presence of a pair\nof complex poles at $p_{\\rm pole}^2 = \\left[(-0.37 \\,\\pm\\, 0.05_{\\rm\nstat}\\,\\pm\\, 0.08_{\\rm sys}) \\pm i\\,(0.66\\, \\pm\\, 0.03_{\\rm stat}\\, \\pm\\,\n0.02_{\\rm sys})\\right]\\, \\mathrm{GeV}^2$, where the first error is statistical\nand the second systematic. The existence of this pair of complex poles, already\nhinted upon in previous works, is thus put onto a firmer basis, thanks to the\nmodel independence and to the careful error propagation of our analysis. For\nthe ghost propagator, the Pad\\'es indicate the existence of a single pole at\n$p^2 = 0$, as expected. In this case, our results also show evidence of a\nbranch cut along the negative real axis of $p^2$. This is corroborated with\nanother type of approximant, the D-Log Pad\\'es, which are better suited to\nstudying functions with a branch cut and are applied here for the first time in\nthis context. Due to particular features and limited statistics of the\ngluon-propagator data, our analysis is inconclusive regarding the presence of a\nbranch cut in the gluon case.",
        "positive": "Large volume behavior of Yang-Mills propagators: We summarize results on finite-volume effects in the propagators of Landau\ngauge Yang-Mills theory using Dyson-Schwinger equations on a 4-dimensional\ntorus. We demonstrate explicitly how the solutions for the gluon and the ghost\npropagator tend towards their respective infinite volume forms in the\ncorresponding limit. We discuss the relation of our solutions with results from\nlattice Monte-Carlo simulations."
    },
    {
        "anchor": "Bulk-preventing actions for SU(N) gauge theories: Lattice gauge field theories may suffer from unphysical \"bulk\" phase\ntransitions at strong lattice gauge coupling. We introduce a one-parameter\nfamily of lattice SU(N) gauge actions which, when used in combination with an\nHMC update algorithm, prevents the appearance of the bulk phase transition. We\nbriefly discuss the (presumed) mechanism behind the prevention of the bulk\ntransition and present test results for different SU(N) gauge groups.",
        "positive": "'t Hooft loops and consistent order parameters for confinement: We study ratios of partition functions in two types of sectors of SU(2), with\nfixed temporal center flux and with static fundamental charge. Both can be used\nas bona fide order parameters for the deconfinement transition."
    },
    {
        "anchor": "Lattice study of QCD at finite chiral density: topology and confinement: In this paper we study the properties of QCD at nonzero chiral density\n$\\rho_5$, which is introduced through chiral chemical potential $\\mu_5$. The\nstudy is performed within lattice simulation of QCD with dynamical rooted\nstaggered fermions. We first check that $\\rho_5$ is generated at nonzero\n$\\mu_5$ and in the chiral limit observe $\\rho_5 \\sim \\Lambda_{QCD}^2 \\mu_5$. We\nalso test the possible connection between confinement and topological\nfluctuations. To this end, we measured the topological susceptibility\n$\\chi_{\\mbox{\\footnotesize top}}$ and string tension $\\sigma$ for various\nvalues of $\\mu_5$. We observed that both string tension and chiral\nsusceptibility grow with $\\mu_5$ and there is a strong correlation between\nthese quantities. We thus conclude that the chiral chemical potential enhances\ntopological fluctuations and that these fluctuations can indeed be closely\nrelated to the strength of confinement.",
        "positive": "Inhomogeneous phases in the chirally imbalanced $2+1$-dimensional\n  Gross-Neveu model and their absence in the continuum limit: We study the $\\mu$-$\\mu_{45}$-$T$ phase diagram of the $2+1$-dimensional\nGross-Neveu model, where $\\mu$ denotes the ordinary chemical potential,\n$\\mu_{45}$ the chiral chemical potential and $T$ the temperature. We use the\nmean-field approximation and two different lattice regularizations with naive\nchiral fermions. An inhomogeneous phase at finite lattice spacing is found for\none of the two regularizations. Our results suggest that there is no\ninhomogeneous phase in the continuum limit. We show that a chiral chemical\npotential is equivalent to an isospin chemical potential. Thus, all results\npresented in this work can also be interpreted in the context of isospin\nimbalance."
    },
    {
        "anchor": "Hadron Spectroscopy with Lattice QCD: The status and prospects for investigations of exotic and conventional\nhadrons with lattice QCD are discussed. The majority of hadrons decay strongly\nvia one or multiple decay-channels, including most of the experimentally\ndiscovered exotic hadrons. Despite this difficult challenge, the properties of\nseveral hadronic resonances have been determined within lattice QCD. To further\ndiscern the spectroscopic properties of various hadrons and to help resolve\ntheir nature we present our suggestions for future analytic and lattice\nstudies.",
        "positive": "BB Potentials in Quenched Lattice QCD: The potentials between two B-mesons are computed in the heavy-quark limit\nusing quenched lattice QCD at $m_\\pi\\sim 400~{\\rm MeV}$. Non-zero central\npotentials are clearly evident in all four spin-isospin channels, (I,s_l) =\n(0,0) , (0,1) , (1,0) , (1,1), where s_l is the total spin of the light degrees\nof freedom. At short distance, we find repulsion in the $I\\ne s_l$ channels and\nattraction in the I=s_l channels. Linear combinations of these potentials that\nhave well-defined spin and isospin in the t-channel are found, in three of the\nfour cases, to have substantially smaller uncertainties than the potentials\ndefined with the s-channel (I,s_l), and allow quenching artifacts from single\nhairpin exchange to be isolated. The BB*\\pi coupling extracted from the\nlong-distance behavior of the finite-volume t-channel potential is found to be\nconsistent with quenched calculations of the matrix element of the isovector\naxial-current. The tensor potentials in both of the s_l = 1 channels are found\nto be consistent with zero within calculational uncertainties."
    },
    {
        "anchor": "Aspects of Chiral Symmetry and the Lattice: I explore the non-perturbative issues entwining lattice gauge theory,\nanomalies, and chiral symmetry. After briefly reviewing the importance of\nchiral symmetry in particle physics, I discuss how anomalies complicate lattice\nformulations. Considerable information can be deduced from effective chiral\nLagrangians, helping interpret the expectations for lattice models and\nelucidating the role of the CP violating parameter $\\Theta$. I then turn to a\nparticularly elegant scheme for exploring this physics on the lattice. This\nuses an auxiliary extra space-time dimension, with the physical world being a\nfour dimensional interface.",
        "positive": "Extended instantons generated on the lattice: We have been able to observe directly extended instantons on the lattice,\nwith a new method that does not require dislocations to measure them, and where\nwe do not perform cooling. We showed, based on the simple Abelian Higgs model\nin $1+1$ dim., that one can extract the instanton and anti-instanton density\nand their size, by measuring the topological charge, $Q_v$ , on sub-volumes $v$\nlarger than the instanton sizes, but smaller than the periodic lattice of size\n$V$. We are working on the generalization for non-abelian models."
    },
    {
        "anchor": "Critical point in heavy-quark region of QCD on fine lattices: We perform a finite-size scaling analysis of the critical point in the\nheavy-quark region of QCD at nonzero temperature. Our previous analysis on the\nBinder cumulant at $N_t=4$ is extended to finer lattices with $N_t=6$ and $8$.\nThe aspect ratio is also extended up to $15$ to suppress the non-singular\ncontribution. High-precision analysis of the Binder cumulant is realized by an\nefficient Monte-Carlo simulation with the hopping-parameter expansion (HPE).\nEffects of higher-order terms in the HPE are incorporated by the reweighting\nmethod.",
        "positive": "Consistency checks for two-body finite-volume matrix elements: II.\n  Perturbative systems: Using the general formalism presented in Refs. [1,2], we study the\nfinite-volume effects for the $\\mathbf{2}+\\mathcal{J}\\to\\mathbf{2}$ matrix\nelement of an external current coupled to a two-particle state of identical\nscalars with perturbative interactions. Working in a finite cubic volume with\nperiodicity $L$, we derive a $1/L$ expansion of the matrix element through\n$\\mathcal O(1/L^5)$ and find that it is governed by two universal\ncurrent-dependent parameters, the scalar charge and the threshold two-particle\nform factor. We confirm the result through a numerical study of the general\nformalism and additionally through an independent perturbative calculation. We\nfurther demonstrate a consistency with the Feynman-Hellmann theorem, which can\nbe used to relate the $1/L$ expansions of the ground-state energy and matrix\nelement. The latter gives a simple insight into why the leading volume\ncorrections to the matrix element have the same scaling as those in the energy,\n$1/L^3$, in contradiction to earlier work, which found a $1/L^2$ contribution\nto the matrix element. We show here that such a term arises at intermediate\nstages in the perturbative calculation, but cancels in the final result."
    },
    {
        "anchor": "One-loop Renormalisation of Lattice QCD Operators for Non-forward Matrix\n  Elements: From Clover to Overlap Fermions: We consider the renormalisation of composite quark-antiquark operators with\none and two lattice covariant derivatives related to the lowest moments of\ngeneralised parton distributions (GPDs) and meson distribution amplitudes\n(DAs). Their matrix elements are calculated in one-loop lattice perturbation\ntheory for non-zero momentum transfer. Using clover and overlap fermions we\npresent the resulting matrices of mixing and renormalisation factors. For\noverlap fermions we explicitly check the absence of mixing with\nlower-dimensional operators of different chirality in particular\nrepresentations of the hypercubic group. This feature favours the use of chiral\nfermions.",
        "positive": "Inclusive rates from smeared spectral densities in the two-dimensional\n  O(3) non-linear $\u03c3$-model: This work employs the spectral reconstruction approach of Ref. [1] to\ndetermine an inclusive rate in the $1+1$ dimensional O(3) non-linear\n$\\sigma$-model, analogous to the QCD part of ${e}^+{e}^- \\rightarrow \\rm\n{hadrons}$. The Euclidean two-point correlation function of the conserved\ncurrent $j$ is computed using Monte Carlo lattice field theory simulations for\na variety of spacetime volumes and lattice spacings. The spectral density of\nthis correlator is related to the inclusive rate for $j \\rightarrow {\\rm X}$ in\nwhich all final states produced by the external current are summed. The\nill-posed inverse problem of determining the spectral density from the\ncorrelation function is made tractable through the determination of smeared\nspectral densities in which the desired density is convolved with a set of\nknown smearing kernels of finite width $\\epsilon$. The smooth energy dependence\nof the underlying spectral density enables a controlled $\\epsilon \\to 0$\nextrapolation in the inelastic region, yielding the real-time inclusive rate\nwithout reference to individual finite-volume energies or matrix elements.\nSystematic uncertainties due cutoff effects and residual finite-volume effects\nare estimated and taken into account in the final error budget. After taking\nthe continuum limit, the results are consistent with the known analytic rate to\nwithin the combined statistical and systematic errors. Above energies where\n20-particle states contribute, the overall precision is sufficient to discern\nthe four-particle contribution to the spectral density."
    },
    {
        "anchor": "Baryon Number Dirac Spectrum in QCD: The relation between the baryon number in QCD at nonzero chemical potential\nand the spectral density of the baryon number Dirac operator, $\\gamma_0(D+m)$,\nis examined. We show that extreme oscillations of the spectral density, caused\nby the QCD sign problem, are essential for the formation of the average baryon\nnumber when $\\mu>m_\\pi/2$. We compute the oscillating region of the spectral\ndensity using chiral perturbation theory. The extreme oscillations have a\nmicroscopic period and are resolved using random matrix theory.",
        "positive": "Nature of the phase transition for finite temperature $N_{\\rm f}=3$ QCD\n  with nonperturbatively O($a$) improved Wilson fermions at $N_{\\rm t}=12$: We study the nature of the finite temperature phase transition for\nthree-flavor QCD. In particular we investigate the location of the critical\nendpoint along the three flavor symmetric line in the light quark mass region\nof the Columbia plot. In the study, the Iwasaki gauge action and the\nnonperturvatively O($a$) improved Wilson-Clover fermion action are employed. We\nnewly generate data at $N_{\\rm t}=12$ and set an upper bound of the critical\npseudoscalar meson mass in the continuum limit $m_{\\rm PS,E}\\lesssim 110$MeV."
    },
    {
        "anchor": "Studies of Critical Phenomena in Causal Dynamical Triangulations on a\n  Torus: This is a Ph.D. thesis that presents the author's findings in the area of\nCausal Dynamical Triangulations. In compliance with Jagiellonian University of\nKrak\\'ow regulations, the document consists of six publications and a general\nsummary, which serves as a guide to assist readers in navigating through the\npublications. Although the six publications that constitute the main content of\nthe thesis are not included in this version of the text on arXiv, they are\nreferred to frequently throughout the document. The original document is\navailable at the following link:\nhttps://fais.uj.edu.pl/documents/41628/150115897/Thesis_DN-skompresowany.pdf",
        "positive": "Display of probability densities for data from a continuous distribution: Based on cumulative distribution functions, Fourier series expansion and\nKolmogorov tests, we present a simple method to display probability densities\nfor data drawn from a continuous distribution. It is often more efficient than\nusing histograms."
    },
    {
        "anchor": "Is there a third-order phase transition in quenched QCD?: We discuss the connection between the contributions of large field\nconfigurations and the large order behavior of perturbation theory. For\nquenched QCD, the sensitivity of the average plaquette to a removal of large\nfield configurations has a narrow peak near beta=5.6. Various analysis of the\norder 10 weak coupling series for the plaquette give robust indications for a\nsingularity in the third derivative of the free energy (second derivative of\nthe plaquette) with respect to beta, near beta = 5.7. We report results of\nnumerical calculations. The peak in the third derivative of the free energy\npresent on 4^4 lattices disappears if the size of the lattice is increased\nisotropically up to a 10^4 lattice. On the other hand, on 4xL^3 lattices, it\npersists when L increases. The location of the peak coincides with the onset of\na non-zero average for the Polyakov loop and seems related to the finite\ntemperature transition. We also discuss the discrepancy between the\nperturbative series and the numerical values of the plaquette.",
        "positive": "Measurement-based quantum simulation of Abelian lattice gauge theories: The digital quantum simulation of lattice gauge theories is expected to\nbecome a major application of quantum computers. Measurement-based quantum\ncomputation is a widely studied competitor of the standard circuit-based\napproach. We formulate a measurement-based scheme to perform the quantum\nsimulation of Abelian lattice gauge theories in general dimensions. The scheme\nuses an entangled resource state that is tailored for the purpose of gauge\ntheory simulation and reflects the spacetime structure of the simulated theory.\nSequential single-qubit measurements with the bases adapted according to the\nformer measurement outcomes induce a deterministic Hamiltonian quantum\nsimulation of the gauge theory on the boundary. We treat as our main example\nthe $\\mathbb{Z}_2$ lattice gauge theory in $2+1$ dimensions, simulated on a\n3-dimensional cluster state. Then we generalize the simulation scheme to\nWegner's lattice models that involve higher-form Abelian gauge fields. The\nresource state has a symmetry-protected topological order with respect to\ngeneralized global symmetries that are related to the symmetries of the\nsimulated gauge theories. We also propose a method to simulate the\nimaginary-time evolution with two-qubit measurements and post-selections."
    },
    {
        "anchor": "The Index Theorem and Universality Properties of the Low-lying\n  Eigenvalues of Improved Staggered Quarks: We study various improved staggered quark Dirac operators on quenched gluon\nbackgrounds in lattice QCD generated using a Symanzik-improved gluon action. We\nfind a clear separation of the spectrum into would-be zero modes and others.\nThe number of would-be zero modes depends on the topological charge as expected\nfrom the Index Theorem, and their chirality expectation value is large\n(approximately 0.7). The remaining modes have low chirality and show clear\nsigns of clustering into quartets and approaching the random matrix theory\npredictions for all topological charge sectors. We conclude that improvement of\nthe fermionic and gauge actions moves the staggered quarks closer to the\ncontinuum limit where they respond correctly to QCD topology.",
        "positive": "Cell processor implementation of a MILC lattice QCD application: We present results of the implementation of one MILC lattice QCD\napplication-simulation with dynamical clover fermions using the\nhybrid-molecular dynamics R algorithm-on the Cell Broadband Engine processor.\nFifty-four individual computational kernels responsible for 98.8% of the\noverall execution time were ported to the Cell's Synergistic Processing\nElements (SPEs). The remaining application framework, including MPI-based\ndistributed code execution, was left to the Cell's PowerPC processor. We\nobserve that we only infrequently achieve more than 10 GFLOPS with any of the\nkernels, which is just over 4% of the Cell's peak performance. At the same\ntime, many of the kernels are sustaining a bandwidth close to 20 GB/s, which is\n78% of the Cell's peak. This indicates that the application performance is\nlimited by the bandwidth between the main memory and the SPEs. In spite of this\nlimitation, speedups of 8.7x (for 8x8x16x16 lattice) and 9.6x (for 16x16x16x16\nlattice) were achieved when comparing a 3.2 GHz Cell processor to a single core\nof a 2.33 GHz Intel Xeon processor. When comparing the code scaled up to\nexecute on a dual-Cell blade and a quad-core dual-chip Intel Xeon blade, the\nspeedups are 1.5x (8x8x16x16 lattice) and 4.1x (16x16x16x16 lattice)."
    },
    {
        "anchor": "Lattice simulation of $(2+1)D$ phonetic solitons and the Renormalization\n  group: The outline of lattice simulations of $(2+1)D$ soliton-propagations in the\nbackground of Weyl spinors is presented. Clifford algebra is applied on\nLuescher's domain decomposition method. The Clifford algebra shows that there\nare loop parts and interpolating surface parts in the Wilson's lattice action.\n  We adopt the Migdal-Kadanoff prescription and the fixed point action in\nmomentum space of Benfatto and Gallavotti, and shows a road map for simulating\nphonetic solitons in materials.\n  Detections of topological anomalies (APS index) in nondestructive testing are\ndiscussed.",
        "positive": "Spectral function at high temperature: For a weakly coupled quantum field at high temperature the classical\napproximation offers a possibility to gain insight into nonperturbative\nreal-time dynamics. I use this to present a nonperturbative approach to the\ncomputation of spectral functions in real time. Results are shown for a scalar\nfield in 2+1 dimensions."
    },
    {
        "anchor": "Euclidian 4d quantum gravity with a non-trivial measure term: We explore an extended coupling constant space of 4d regularized Euclidean\nquantum gravity, defined via the formalism of dynamical triangulations. We add\na measure term which can also serve as a generalized higher curvature term and\ndetermine the phase diagram and the geometries dominating in the various\nregions. A first order phase transition line is observed, but no second order\ntransition point is located. As a consequence we cannot attribute any continuum\nphysics interpretation to the so-called crinkled phase of 4d dynamical\ntriangulations.",
        "positive": "Baryons in/and Lattice QCD: Anchoring our understanding of low-energy nuclear and hadronic physics to the\nfundamental theory of strong interactions, QCD, remains and outstanding\nchallenge for physicists. Lattice QCD and chiral perturbation theory are the\nmost powerful theoretical tools we have at our disposal to make this\nconnection. These tools share a symbiotic relationship as chiral perturbation\ntheory is used to understand the light quark mass dependence of observables,\nwhile lattice QCD is used to determine the values of the unknown operator\ncoefficients appearing in the chiral Lagrangian. In this talk, I review our\npresent understanding of select single baryon properties from lattice QCD and\nchiral perturbation theory, highlighting some of the challenges and discussing\nsome unresolved puzzles."
    },
    {
        "anchor": "Dirac Spectrum, Axial Anomaly and the QCD Chiral Phase Transition: The QCD phase transition is studied on $16^3$ and $32^3 \\times 4$ lattices\nboth with and without quark loops. We introduce a new zero-flavor or quenched\nspecies of quark $\\zeta$ and study the resulting chiral condensate, $\\azbz$ as\na function of the $\\zeta$ mass, $m_\\zeta$. By examining $\\azbz$ for $10^{-10}\n\\le m_\\zeta \\le 10$ we gain considerable information about the spectrum of\nDirac eigenvalues. A comparison of $ma=0.01$ and 0.025 shows little dependence\nof the Dirac spectrum on such a light, dynamical quark mass, after an overall\nshift in $\\beta$ is removed. The presence of sufficient small eigenvalues to\nsupport anomalous chiral symmetry breaking in the high temperature phase is\nexamined quantitatively. In an effort to enhance these small eigenvalues,\n$\\azbz$ is also examined in the pure gauge theory in the region of the\ndeconfinement transition with unexpected results. Above the critical\ntemperature, the three $Z_3$ phases show dramatically different chiral\nbehavior. Surprisingly, the real phase shows chiral symmetry, suggesting that a\nsystem with one flavor of staggered fermion at $N_t=4$ will possess a chiral a\nphase transition---behavior not expected in the continuum limit.",
        "positive": "Testing the Standard Model under the weight of heavy flavors: I review recently completed (since Lattice 2013) and ongoing lattice\ncalculations in charm and bottom flavor physics. A comparison of the precision\nof lattice and experiment is made using both current experimental results and\nprojected experimental precision in 2020. The combination of experiment and\ntheory reveals several tensions between nature and the Standard Model. These\ntensions are reviewed in light of recent lattice results."
    },
    {
        "anchor": "Exact lattice Ward-Takahashi identity for the N=1 Wess-Zumino model: We consider a lattice formulation of the four dimensional N=1 Wess-Zumino\nmodel that uses the Ginsparg-Wilson relation. This formulation has an exact\nsupersymmetry on the lattice. We show that the corresponding Ward-Takahashi\nidentity is satisfied, both at fixed lattice spacing and in the continuum\nlimit. The calculation is performed in lattice perturbation theory up to order\n$g^2$ in the coupling constant. We also show that this Ward-Takahashi identity\ndetermines the finite part of the scalar and fermion renormalization wave\nfunctions which automatically leads to restoration of supersymmetry in the\ncontinuum limit. In particular, these wave functions coincide in this limit.",
        "positive": "Monopole-Antimonopole Correlation Functions in 4D U(1) Gauge Theory: We study the two-point correlator of a modified Confined-Coulomb transition\norder parameter in four dimensional compact U(1) lattice gauge theory with\nWilson action. Its long distance behavior in the confined phase turns out to be\ngoverned by a single particle decay. The mass of this particle is computed and\nfound to be in agreement with previous calculations of the 0^{++} gaugeball\nmass. Remarkably, our order parameter allows to extract a good signal to noise\nratio for masses with low statistics. The results we present provide a\nnumerical check of a theorem about the structure of the Hilbert space\ndescribing the confined phase of four dimensional compact U(1) lattice gauge\ntheories."
    },
    {
        "anchor": "How many quantum gates do gauge theories require?: We discuss the implementation of lattice gauge theories on digital quantum\ncomputers, focusing primarily on the number of quantum gates required to\nsimulate their time evolution. We find that to compile quantum circuits, using\navailable state-of-the-art methods with our own augmentations, the cost of a\nsingle time step of an elementary plaquette is beyond what is reasonably\npractical in the current era of quantum hardware. However, we observe that such\ncosts are highly sensitive to the truncation scheme used to derive different\nHamiltonian formulations of non-Abelian gauge theories, emphasizing the need\nfor low-dimensional truncations of such models in the same universality class\nas the desired theories.",
        "positive": "The lattice Schwinger model with the SW action: We perform a model study on the 2-flavor lattice Schwinger model using\nstandard Wilson and ${\\cal O}(a)$ improved Sheikholeslami-Wohlert (SW) action.\nWe find, that the phase diagram is altered, the critical line shifted closer\ntowards its continuum value $\\kappa_c=0.25$. We find no improvement in the\nrotation invariance of meson propagators; the scaling of the Schwinger mass is\nconsiderably improved, high momentum states are not. The additional cost of\n$\\approx 30 %$ CPU-time is highly justified when calculating masses, but not\nfor high momentum observables."
    },
    {
        "anchor": "Multigrid meets Neural Nets: We present evidence that multigrid (MG) works for wave equations in\ndisordered systems, e.g. in the presence of gauge fields, no matter how strong\nthe disorder. We introduce a \"neural computations\" point of view into large\nscale simulations: First, the system must learn how to do the simulations\nefficiently, then do the simulation (fast). The method can also be used to\nprovide smooth interpolation kernels which are needed in multigrid Monte Carlo\nupdates.",
        "positive": "Life Outside the Golden Window: Statistical Angles on the\n  Signal-to-Noise Problem: Lattice QCD simulations of multi-baryon correlation functions can predict the\nstructure and reactions of nuclei without encountering the baryon chemical\npotential sign problem. However, they suffer from a signal-to-noise problem\nwhere Monte Carlo estimates of observables have quantum fluctuations that are\nexponentially larger than their average values. Recent lattice QCD results\ndemonstrate that the complex phase of baryon correlations functions relates the\nbaryon signal-to-noise problem to a sign problem and exhibits unexpected\nstatistical behavior resembling a heavy-tailed random walk on the unit circle.\nEstimators based on differences of correlation function phases evaluated at\ndifferent Euclidean times are discussed that avoid the usual signal-to-noise\nproblem, instead facing a signal-to-noise problem as the time interval\nassociated with the phase difference is increased, and allow hadronic\nobservables to be determined from arbitrarily large-time correlation functions."
    },
    {
        "anchor": "An Almost Perfect Lattice Action for infrared QCD: A block-spin transformation on the dual lattice leads us to an almost perfect\nlattice action for monopoles and strings in QCD. The perfect operator for a\nstatic quark potential is fixed when we compare the above action with the\nperfect action obtained analytically after infinite-step block-spin\ntransformations in a simple case. The continuum rotational invariance is\nrestored and the physical value of the string tension is reproduced fairly\nwell. Gauge independence of the abelian and the monopole scenario is discussed.",
        "positive": "Nucleon structure from mixed action calculations using 2+1 flavors of\n  asqtad sea and domain wall valence fermions: We present high statistics results for the structure of the nucleon from a\nmixed-action calculation using 2+1 flavors of asqtad sea and domain wall\nvalence fermions. We perform extrapolations of our data based on different\nchiral effective field theory schemes and compare our results with available\ninformation from phenomenology. We discuss vector and axial form factors of the\nnucleon, moments of generalized parton distributions, including moments of\nforward parton distributions, and implications for the decomposition of the\nnucleon spin."
    },
    {
        "anchor": "Gradient flow scale setting with tree-level improvement: Lattice scales defined using gradient flow are typically very precise, while\nalso easy to calculate. However, different definitions of flows and operators\ncan differ significantly, suggesting possible systematical effects. Using a\nsubset of RBC-UKQCD's 2+1 flavor domain wall fermion and Iwasaki gauge action\nensembles, we explore differences between $\\sqrt{t_0}$ and $w_0$ gradient flow\nscales, compare the impact of different operators to define the energy density,\nand study the effect of using tree-level improvement for the gradient flow. We\nfind that for this set of gauge field ensembles Zeuthen flow with Symanzik\noperators has the most consistent approach to the continuum limit and exhibit\nvery small cutoff corrections. Tree-level improvement, traditionally used in\nstep-scaling studies, significantly reduces the spread between different\noperators, but does not lead to an overall improvement when it comes to\nreducing cutoff effects for gradient flow scales $\\sqrt{t_0}$ or $w_0$.",
        "positive": "Status of reproducibility and open science in hep-lat in 2021: As a fully computational discipline, Lattice Field Theory has the potential\nto give results that anyone with sufficient computational resources can\nreproduce, going from input parameters to published numbers and plots correct\nto the last byte. After briefly motivating and outlining some of the key steps\nin making lattice computations reproducible, this contribution presents the\nresults of a survey of all 1,229 submissions to the hep-lat arXiv in 2021 of\nhow explicitly reproducible each is. Areas where LFT has historically been well\nahead of the curve are highlighted, as are areas where there are opportunities\nto do more."
    },
    {
        "anchor": "Monte Carlo computation of the effective potential for the three\n  dimensional Ising system: Using a novel finite size scaling Monte Carlo technique, we calculate the\nfour, six and eight point renormalized coupling constants defined at zero\nmomentum for the three dimensional Ising system. Our values of the six and\neight point coupling constants are significantly different from those obtained\nfrom other methods.",
        "positive": "The Gluon Propagator without lattice Gribov copies: We study the gluon propagator in quenched lattice QCD using the Laplacian\ngauge which is free of lattice Gribov copies. We compare our results with those\nobtained in the Landau gauge on the lattice, as well as with various\napproximate solutions of the Dyson Schwinger equations. We find a finite value\n$\\sim (445 \\rm{MeV})^{-2}$ for the renormalized zero-momentum propagator\n(taking our renormalization point at 1.943 GeV), and a pole mass $\\sim 640 \\pm\n140$ MeV."
    },
    {
        "anchor": "Is There Quantum Gravity in Two Dimensions?: A hybrid model which allows to interpolate between the (original) Regge\napproach and dynamical triangulations is introduced. The gained flexibility in\nthe measure is exploited to study dynamical triangulation in a fixed geometry.\nOur numerical results support KPZ exponents. A critical assessment concerning\nthe apparent lack of gravitational effects in two dimensions follows.",
        "positive": "Fermion mass without symmetry breaking: We examine a model of reduced staggered fermions in three dimensions\ninteracting through an $SO(4)$ invariant four fermion interaction. The model is\nsimilar to that considered in a recent paper by Ayyer and Chandrasekharan\n\\cite{Ayyar:2014eua}. We present theoretical arguments and numerical evidence\nwhich support the idea that the system develops a mass gap for sufficiently\nstrong four fermi coupling.{\\it without} producing a symmetry breaking fermion\nbilinear condensate. Massless and massive phases appear to be separated by a\ncontinuous phase transition."
    },
    {
        "anchor": "Nuclear Physics Review: Anchoring low-energy nuclear physics to the fundamental theory of strong\ninteractions remains an outstanding challenge. I review the current progress\nand challenges of the endeavor to use lattice QCD to bridge this connection.\nThis is a particularly exciting time for this line of research as demonstrated\nby the spike in the number of different collaborative efforts focussed on this\nproblem and presented at this conference. I first digress and discuss the 2013\nKen Wilson Award.",
        "positive": "The scalar spectrum of many-flavour QCD: The LatKMI collaboration is studying systematically the dynamical properties\nof N_f = 4,8,12,16 SU(3) gauge theories using lattice simulations with (HISQ)\nstaggered fermions. Exploring the spectrum of many-flavour QCD, and its scaling\nnear the chiral limit, is mandatory in order to establish if one of these\nmodels realises the Walking Technicolor scenario. Although lattice technologies\nto study the mesonic spectrum are well developed, scalar flavour-singlet states\nstill require extra effort to be determined. In addition, gluonic observables\nusually require large-statistic simulations and powerful noise-reduction\ntechniques. In the following, we present useful spectroscopic methods to\ninvestigate scalar glueballs and scalar flavour-singlet mesons, together with\nthe current status of the scalar spectrum in N_f = 12 QCD from the LatKMI\ncollaboration."
    },
    {
        "anchor": "Zero Lattice Sound: We study the N_f-flavor Gross-Neveu model in 2+1 dimensions with a baryon\nchemical potential mu, using both analytical and numerical methods. In\nparticular, we study the self-consistent Boltzmann equation in the Fermi liquid\nframework using the quasiparticle interaction calculated to O(1/N_f), and find\nsolutions for zero sound propagation for almost all mu > mu_c, the critical\nchemical potential for chiral symmetry restoration. Next we present results of\na numerical lattice simulation, examining temporal correlation functions of\nmesons defined using a point-split interpolating operator, and finding evidence\nfor phonon-like behaviour characterised by a linear dispersion relation in the\nlong wavelength limit. We argue that our results provide the first evidence for\na collective excitation in a lattice simulation.",
        "positive": "Background field method in the gradient flow: In perturbative consideration of the Yang--Mills gradient flow, it is useful\nto introduce a gauge non-covariant term (\"gauge-fixing term\") to the flow\nequation that gives rise to a Gaussian damping factor also for gauge degrees of\nfreedom. In the present paper, we consider a modified form of the gauge-fixing\nterm that manifestly preserves covariance under the background gauge\ntransformation. It is shown that our gauge-fixing term does not affect\ngauge-invariant quantities as the conventional gauge-fixing term. The\nformulation thus allows a background gauge covariant perturbative expansion of\nthe flow equation that provides, in particular, a very efficient computational\nmethod of expansion coefficients in the small flow time expansion. The\nformulation can be generalized to systems containing fermions."
    },
    {
        "anchor": "High-Precision Thermodynamics and Hagedorn Density of States: We compute the entropy density of the confined phase of QCD without quarks on\nthe lattice to very high accuracy. The results are compared to the entropy\ndensity of free glueballs, where we include all the known glueball states below\nthe two-particle threshold. We find that an excellent, parameter-free\ndescription of the entropy density between 0.7Tc and Tc is obtained by\nextending the spectrum with the exponential spectrum of the closed bosonic\nstring.",
        "positive": "The U(1) Problem in Chiral Random Matrix Models: We show that conventional asymmetric chiral random matrix models (ChRMM),\nwith a gaussian distribution in the asymmetry, provide for a screening of the\ntopological charge and a resolution of the $U(1)$ problem in the unquenched\napproximation. Our exact results to order $1/N$ are in agreement with numerical\nestimates using large ensembles of asymmetric ChRMM with gaussian\ndistributions."
    },
    {
        "anchor": "Ghost-gluon coupling, power corrections and $\u039b_{\\overline {\\rm\n  MS}}$ from twisted-mass lattice QCD at Nf=2: We present results concerning the non-perturbative evaluation of the\nghost-gluon running QCD coupling constant from $N_f=2$ twisted-mass lattice\ncalculations. A novel method for calibrating the lattice spacing, independent\nof the string tension and hadron spectrum is presented with results in\nagreement with previous estimates. The value of $\\Lambda_{\\overline{MS}}$ is\ncomputed from the running of the QCD coupling only after extrapolating to zero\ndynamical quark mass and after removing a non-perturbative OPE contribution\nthat is assumed to be dominated by the dimension-two $\\VEV{A^2}$ gluon\ncondensate. The effect due to the dynamical quark mass in the determination of\n$\\Lams$ is discussed.",
        "positive": "Recent progress on color confinement: The status is reviewed of the dual superconductivity of QCD vacuum as a\nmechanism of color confinement."
    },
    {
        "anchor": "QCD phase diagram and equation of state in background electric fields: The phase diagram and the equation of state of QCD is investigated in the\npresence of weak background electric fields by means of continuum extrapolated\nlattice simulations. The complex action problem at nonzero electric field is\ncircumvented by a novel Taylor expansion, enabling the determination of the\nlinear response of the thermal QCD medium to constant electric fields -- in\ncontrast to simulations at imaginary electric fields, which, as we demonstrate,\ninvolve an infrared singularity. Besides the electric susceptibility of QCD\nmatter, we determine the dependence of the Polyakov loop on the field strength\nto leading order. Our results indicate a plasma-type behavior with a negative\nsusceptibility at all temperatures, as well as an increase in the transition\ntemperature as the electric field grows.",
        "positive": "Step Scaling with off-shell renormalisation: We make use of twisted boundary conditions for off-shell Rome-Southampton\nrenormalisation. This allows to define the vertex function precisely, at a\nfixed physical momentum that need not be one of the Fourier modes of a\nsimulation. This definition includes choosing the orientation with respect to\nlattice axes, and so lattice artefacts including ${\\cal O}(4)$ breaking then\nhave a valid Symanzik expansion. Excellent statistical precision is afforded by\nvolume plane-wave sources, enabling both a theoretically and statistically\nclean continuum limit to be taken. Thereafter all $p^2$ dependence can be\nunambiguously identified as continuum anomolous running.\n  The use of non-exceptional momenta has been found to greatly reduce the\ndependence of non-perturbative vertex functions on both mass and $p^2$. We\nillustrate how this can be developed into a practical scheme for step-scaling\nthe RI/SMOM approach with initial results. The size of the possible steps is\ncontinuous, rather than discrete allowing one to take arbitrarily small steps,\nand the scheme inherits from RI/MOM the property that it is easy to implement\nfor general operators."
    },
    {
        "anchor": "Probing for Instanton Quarks with epsilon-Cooling: We use epsilon-cooling, adjusting at will the order a^2 corrections to the\nlattice action, to study the parameter space of instantons in the background of\nnon-trivial holonomy and to determine the presence and nature of constituents\nwith fractional topological charge at finite and zero temperature for SU(2). As\nan additional tool, zero temperature configurations were generated from those\nat finite temperature with well-separated constituents. This is achieved by\n\"adiabatically\" adjusting the anisotropic coupling used to implement finite\ntemperature on a symmetric lattice. The action and topological charge density,\nas well as the Polyakov loop and chiral zero-modes are used to analyse these\nconfigurations. We also show how cooling histories themselves can reveal the\npresence of constituents with fractional topological charge. We comment on the\ninterpretation of recent fermion zero-mode studies for thermalized ensembles at\nsmall temperatures.",
        "positive": "A spin-charge flip symmetric fixed point in 2+1d with massless Dirac\n  fermions: We study a quantum phase transition of electrons on a two-dimensional square\nlattice. Our lattice model preserves the full $\\mathrm{O}(4)$ symmetry of free\nspin-$\\frac{1}{2}$ Dirac fermions on a bipartite lattice. In particular, it not\nonly preserves the usual $\\mathrm{SO}(4)$ (spin-charge) symmetry like in the\nhalf-filling Hubbard model, but also preserves a $\\mathbb{Z}_2$ spin-charge\nflip symmetry. Using sign-problem-free Monte Carlo simulation, we find a second\norder quantum phase transition from a massless Dirac phase to a massive phase\nwith spontaneously chosen spin order or charge order, which become\nsimultaneously critical at the critical point. We analyze all the possible\n4-fermion couplings in the continuum respecting the lattice symmetry, and\nidentify the terms whose effective potential in the broken phase is consistent\nwith the numerical results. Using renormalization group calculations in the\ncontinuum, we show the existence of the new spin-charge flip symmetric fixed\npoint and calculate its critical exponents."
    },
    {
        "anchor": "Topological susceptibility with the asqtad action: Chiral perturbation theory predicts that in quantum chromodynamics (QCD),\nlight dynamical quarks suppress the gauge-field topological susceptibility of\nthe vacuum. The degree of suppression depends on quark multiplicity and masses.\nIt provides a strong consistency test for fermion formulations in lattice QCD.\nSuch tests are especially important for staggered fermion formulations that\nlack a full chiral symmetry and use the \"fourth-root\" procedure to achieve the\ndesired number of sea quarks. Over the past few years we have measured the\ntopological susceptibility on a large database of 18 gauge field ensembles,\ngenerated in the presence of 2+1 flavors of dynamical asqtad quarks with up and\ndown quark masses ranging from 0.05 to 1 in units of the strange quark mass and\nlattice spacings ranging from 0.045 fm to 0.12 fm. Our study also includes\nthree quenched ensembles with lattice spacings ranging from 0.06 to 0.12 fm. We\nconstruct the topological susceptibility from the integrated point-to-point\ncorrelator of the discretized topological charge density F-Fdual. To reduce its\nvariance, we model the asymptotic tail of the correlator. The continuum\nextrapolation of our results for the topological susceptibility agrees nicely\nat small quark mass with the predictions of lowest-order SU(3) chiral\nperturbation theory, thus lending support to the validity of the fourth-root\nprocedure.",
        "positive": "Sea Quark Effects on Quarkonia: We study the effects of two dynamical sea quarks on the spectrum of heavy\nquarkonia. Within the non-relativistic approach to Lattice QCD we found\nsizeable changes to the hyperfine splitting, but we could not observe any\nchanges for the fine structure. We also investigated the scaling behaviour of\nour results for several different lattice spacings."
    },
    {
        "anchor": "Scope and convergence of the hopping parameter expansion in finite\n  temperature QCD with heavy quarks around the critical point: Hopping parameter expansion is a useful tool to investigate heavy dynamical\nquarks in lattice QCD, while the range of its applicability has been sometimes\nquestioned. We study the convergence and the valid range of the hopping\nparameter expansion in the determination of the critical point (critical quark\nmass) of QCD with heavy quarks at finite temperature and density. On lattices\nwith sufficiently large spatial extent, the terms in the hopping parameter\nexpansion are classified into Wilson loop terms and Polyakov-type loop terms.\nWe first study the case of the worst convergence in which all the gauge link\nvariables are unit matrices and thus the Wilson loops and the Polyakov-type\nloops get their maximum values. We perform explicit calculation up to more than\n100th order of the hopping parameter expansion. We show that the hopping\nparameter expansion is convergent up to the chiral limit of free Wilson quarks.\nWe then perform a Monte-Carlo simulation to measure correlation among\nPolyakov-type loop terms up to the 20th order of the hopping parameter\nexpansion. In previous studies, strong correlation between the leading order\nPolyakov loop term and the next-to-leading order bent Polyakov loop terms was\nreported and used to construct an effective theory to incorporate the\nnext-to-leading order effect by a shift of the leading order coupling\nparameter. We establish that the strong correlation among Polyakov-type loop\nterms holds also at higher orders of the hopping parameter expansion, and\nextend the effective theory to incorporate higher-order effects up to high\norders. Using the effective theory, we study the truncation error of the\nhopping parameter expansion. We find that the previous next-to-leading order\nresult of the critical point for $N_t=4$ are well reliable. For $N_t \\ge 6$, we\nneed to incorporate higher-order effects in the effective theory.",
        "positive": "A Lattice QCD Analysis of the Strangeness Magnetic Moment of the Nucleon: The outcome of the SAMPLE Experiment suggests that the strange-quark\ncontribution to the nucleon magnetic moment, G_M^s(0), may be greater than\nzero. This result is very difficult to reconcile with expectations based on the\nsuccessful baryon magnetic-moment phenomenology of the constituent quark model.\nWe show that careful consideration of chiral symmetry reveals some rather\nunexpected properties of QCD. In particular, it is found that the valence\nu-quark contribution to the magnetic moment of the neutron can differ by more\nthan 50% from its contribution to the Xi^0 magnetic moment. This hitherto\nunforeseen result leads to the value G_M^s(0) = -0.16 +/- 0.18 with a\nsystematic error, arising from the relatively large strange quark mass used in\nexisting lattice calculations, that would tend to shift G_M^s(0) towards small\npositive values."
    },
    {
        "anchor": "Scalar QED with Rydberg atoms: We review recent suggestions to quantum simulate scalar electrodynamics (the\nlattice Abelian Higgs model) in $1+1$ dimensions with rectangular arrays of\nRydberg atoms. We show that platforms made publicly available recently allow\nempirical explorations of the critical behavior of quantum simulators. We\ndiscuss recent progress regarding the phase diagram of two-leg ladders,\neffective Hamiltonian approaches and the construction of hybrid quantum\nalgorithms targeting hadronization in collider physics event generators.",
        "positive": "Center flux correlation in SU(2) Yang-Mills theory: By using the method of center projection the center vortex part of the gauge\nfield is isolated and its propagator is evaluated in the center Landau gauge,\nwhich minimizes the open 3-dimensional Dirac volumes of non-trivial center\nlinks bounded by the closed 2-dimensional center vortex surfaces. The center\nfield propagator is found to dominate the gluon propagator (in Landau gauge) in\nthe low momentum regime and to give rise to an OPE correction to the latter of\n${\\sqrt{\\sigma}}/{p^3}$.The screening mass of the center vortex field vanishes\nabove the critical temperature of the deconfinement phase transition, which\nnaturally explains the second order nature of this transition consistent with\nthe vortex picture. Finally, the ghost propagator of maximal center gauge is\nfound to be infrared finite and thus shows that the coset fields play no role\nfor confinement."
    },
    {
        "anchor": "QCD thermodynamics with $N_f=2+1$ near the continuum limit at realistic\n  quark masses: We report on our study of QCD thermodynamics with 2+1 flavors of dynamical\nquarks. In this proceeding we present several thermodynamic quantities and our\nrecent calculation of the critical temperature. In order to investigate the\nthermodynamic properties of QCD near the continuum limit we adopt improved\nstaggered (p4) quarks coupled with tree-level Symanzik improved glue on $N_t=4$\nand 6 lattices. The simulations are performed with a physical value of the\nstrange quark mass and light quark masses which are in the range of\n$m_q/m_s=0.05-0.4$. The lightest quark mass corresponds to a pion mass of about\n150 MeV.",
        "positive": "S-wave meson-baryon potentials with strangeness from Lattice QCD: We study the s-wave I=2 \\pi \\Sigma and I=1 KN interactions from 2+1 flavor\nfull lattice QCD simulation for relatively heavy quark mass corresponding to\nm_{\\pi}=700 MeV. The s-wave meson-baryon potentials are obtained from the\nNambu-Bethe-Salpeter amplitudes. Potentials in both channels reveal short range\nrepulsions, which suggest the importance of the Pauli blocking effect. The I=1\nKN scattering phase shifts are calculated and compared with the existing\nexperimental data."
    },
    {
        "anchor": "The QCD equation of state with dynamical quarks: The present paper concludes our investigation on the QCD equation of state\nwith 2+1 staggered flavors and one-link stout improvement. We extend our\nprevious study [JHEP 0601:089 (2006)] by choosing even finer lattices. Lattices\nwith $N_t=6,8$ and 10 are used, and the continuum limit is approached by\nchecking the results at $N_t=12$. A Symanzik improved gauge and a stout-link\nimproved staggered fermion action is utilized. We use physical quark masses,\nthat is, for the lightest staggered pions and kaons we fix the $m_\\pi/f_K$ and\n$m_K/f_K$ ratios to their experimental values. The pressure, the interaction\nmeasure, the energy and entropy density and the speed of sound are presented as\nfunctions of the temperature in the range $100 ...1000 \\textmd{MeV}$. We give\nestimates for the pion mass dependence and for the contribution of the charm\nquark. We compare our data to the equation of state obtained by the \"hotQCD\"\ncollaboration.",
        "positive": "Lattice study of $B\\to \u03c0$ semileptonic decay using nonrelativistic\n  lattice QCD: We present an exploratory lattice study of $B\\to\\pi$ semileptonic decay form\nfactors using the nonrelativistic lattice QCD for heavy quark with Wilson light\nquark on a $16^3 \\times 32$ quenched lattice at $\\beta=5.8$. The matrix\nelements are calculated at eight values of heavy quark mass in a range of\n$1.5-8$ GeV and with three values of light quark mass. The $1/m_B$ corrections\nto the matrix elements are found to be fairly small except for the spatial\ncomponent proportional to the $B$ meson momentum. We find that the $q^2$\ndependence of the form factor $f^+(q^2)$ near $q_{max}^2$ becomes much stronger\nfor larger heavy quark mass, which may suggest the increase of a pole\ncontribution. We perform a model independent fit of the form factors and study\nwhether the $q^2$ dependence is consistent with the pole contribution. Although\nthe soft pion theorem predicts $f^0(q_{max}^2)=f_B/f_{\\pi}$ in the chiral\nlimit, we observe a significant violation of this relation."
    },
    {
        "anchor": "What lattice QCD spectral functions can tell us about heavy quarkonium\n  in the QGP: The bound states of a heavy quark and antiquark ($c\\bar{c}, b\\bar{b}$) are\nideal probes to explore the quark-gluon plasma created in relativistic\nheavy-ion collisions at the RHIC and LHC. Not only have they become\nexperimentally accessible with high precision but also efficient tools, so\ncalled effective field theories (EFT) have been developed to treat them\ntheoretically. Here we present recent progress in understanding the in-medium\nbehavior of heavy-quarkonium with the help of EFT's combined with\nnon-perturbative and first principles simulations in lattice QCD. In particular\nwe discuss computations of heavy quarkonium spectral functions with the help of\nBayesian unfolding methods and the physics we can extract from them.\nLimitations and the underlying assumptions of the used approaches are pointed\nout.",
        "positive": "Chiral condensate, susceptibilities, critical coupling and indices in\n  QED$_4$: We measure chiral susceptibilities in the Coulomb phase of noncompact QED$_4$\nin $8^4, 10^4$ and $12^4$ lattices. The MFA approach allows simulations in the\nchiral limit which are therefore free from arbitrary mass extrapolations. Using\nthe critical couplings extracted from these calculations, we study the critical\nbehaviour of the chiral condensate, which we find in disagreement with the\npredictions of logarithmically improved scalar Mean Field theory."
    },
    {
        "anchor": "The transition temperature in QCD: We present a detailed calculation of the transition temperature in QCD with\ntwo light and one heavier (strange) quark mass on lattices with temporal extent\nN_t =4 and 6. Calculations with improved staggered fermions have been performed\nfor various light to strange quark mass ratios in the range, 0.05 <= m_l/m_s <=\n0.5, and with a strange quark mass fixed close to its physical value. From a\ncombined extrapolation to the chiral (m_l -> 0) and continuum (aT = 1/N_t -> 0)\nlimits we find for the transition temperature at the physical point T_c r_0 =\n0.457(7) where the scale is set by the Sommer-scale parameter r_0 defined as\nthe distance in the static quark potential at which the slope takes on the\nvalue, (dV_qq(r)/dr)_r=r_0 = 1.65/r_0^2. Using the currently best known value\nfor r_0 this translates to a transition temperature T_c = 192(7)(4)MeV. The\ntransition temperature in the chiral limit is about 3% smaller. We discuss\ncurrent ambiguities in the determination of T_c in physical units and also\ncomment on the universal scaling behavior of thermodynamic quantities in the\nchiral limit.",
        "positive": "Monte Carlo simulation of systems with complex-valued measures: A simulation method based on the RG blocking is shown to yield statistical\nerrors smaller than that of the crude MC using absolute values of the original\nmeasures. The new method is particularly suitable to apply to the sign problem\nof indefinite or complex-valued measures. We demonstrate the many advantages of\nthis method in the simulation of 2D Ising model with complex-valued\ntemperature."
    },
    {
        "anchor": "A General Implicit Splitting for Stabilizing Numerical Simulations of\n  Langevin Equations: In this paper is described a general 2-nd order accurate (weak sense)\nprocedure for stablizing Monte-Carlo simulations of Ito stochastic differential\nequations. The splitting procedure includes explicit Runge-Kutta methods,\nsemi-implicit methods, and trapezoidal Rule. We prove the semi-implicit method\nof Oettinger and note that it may be generalized for arbitrary splittings.",
        "positive": "Pion mass and the PCAC relation in the overlap fermion formalism: Gauged\n  Gross-Neveu model on a lattice: We investigate chiral properties of the overlap lattice fermion by using\nsolvable model in two dimensions, the gauged Gross-Neveu model. In this model,\nthe chiral symmetry is spontaneously broken in the presence of small but finite\nfermion mass. We calculate the quasi-Nambu-Goldstone(NG) boson mass as a\nfunction of the bare fermion mass and two parameters in the overlap formula. We\nfind that the quasi-NG boson mass has desired properties as a result of the\nextended chiral symmetry found by L\\\"uscher. We also examine the PCAC relation\nand find that it is satisfied in the continuum limit. Comparison between the\noverlap and Wilson lattice fermions is made."
    },
    {
        "anchor": "Series Expansions for the Massive Schwinger Model in Hamiltonian lattice\n  theory: It is shown that detailed and accurate information about the mass spectrum of\nthe massive Schwinger model can be obtained using the technique of\nstrong-coupling series expansions. Extended strong-coupling series for the\nenergy eigenvalues are calculated, and extrapolated to the continuum limit by\nmeans of integrated differential approximants, which are matched onto a\nweak-coupling expansion. The numerical estimates are compared with exact\nresults, and with finite-lattice results calculated for an equivalent lattice\nspin model with long-range interactions. Both the heavy fermion and the light\nfermion limits of the model are explored in some detail.",
        "positive": "Baryon masses with improved staggered quarks: The MILC collaboration's simulations with improved staggered quarks are being\nextended with runs at a lattice spacing of 0.06 fm with quark masses down to\none tenth the strange quark mass. We give a brief introduction to these new\nsimulations and the determination of the lattice spacing. Then we combine these\nnew runs with older results to study the masses of the nucleon and the Omega\nminus in the continuum and chiral limits."
    },
    {
        "anchor": "The renormalization group step scaling function of the 2-flavor SU(3)\n  sextet model: We investigate the discrete $\\beta$ function of the 2-flavor SU(3) sextet\nmodel using the finite volume gradient flow scheme. Our results, using clover\nimproved nHYP smeared Wilson fermions, follow the (non-universal) 4-loop\n$\\overline{\\textrm{MS}}$ perturbative predictions closely up to $g^2 \\approx\n5.5$, the strongest coupling reached in our simulation. At strong couplings the\nresults are in tension with a recently published work using the same gradient\nflow renormalization scheme with staggered fermions. Since these calculations\ndefine the discrete $\\beta$ function in the same continuum renormalization\nscheme, they should lead to the same continuum predictions, irrespective of the\nlattice fermion action.\n  In order to test systematic effects in our computation we compare two\ndifferent lattice operators, three different flow definitions, and two volume\nextrapolations. We find agreement among these different approaches in the\ncontinuum limit when the gradient flow parameter $c\\gtrsim0.35$. Considering\nthe potential phenomenological impact of this model, it is important to\nunderstand the origin of the disagreement between our work and the staggered\nfermion results.",
        "positive": "$B_K$ with improved staggered fermions: analysis using SU(3) staggered\n  chiral perturbation theory: We report updated results for $B_K$ using HYP-smeared staggered valence\nquarks on MILC asqtad lattices based on an analysis using SU(3) staggered\nchiral perturbation theory. The most important new feature of our data sample\nis the inclusion of a fourth (\"ultrafine\") lattice spacing. This improves the\ncontrol over the continuum extrapolation and errors due our use of one-loop\nperturbative matching. We present a complete updated error budget, which leads\nto $B_K(\\text{NDR}, \\mu = 2 \\text{GeV}) = 0.5309 \\pm 0.0051 \\pm 0.0424$ and\n$\\hat{B}_K = B_K(\\text{RGI}) = 0.727 \\pm 0.07 \\pm 0.058$. The results of the\nSU(3) analysis are inferior to those based on SU(2) staggered chiral\nperturbation theory, primarily because of the dependence on the Bayesian priors\nwe use in the SU(3) fits."
    },
    {
        "anchor": "Screening masses in thermal and dense medium: Screening masses of different hadronic states are studied in thermal and\ndense medium on lattice. It has been found that screening masses increase with\nthe temperature. In deconfinement phase, chemical potential enhances the\nscreening masses. We use the normalization with respect to lowest Matsubara\nfrequency to characterize dissolving of hadronic bound states at high\ntemperatures. It has been found that different hadronic states have different\ndissolving temperatures and their survivals are considerably improved at finite\nchemical potentials.",
        "positive": "Inclusion of heavy spin effects in the $u d \\bar{b} \\bar{b}$\n  $I(J^{P})=0(1^{-})$ four-quark channel in the Born-Oppenheimer approximation: We refine our previous study of a $u d \\bar{b} \\bar{b}$ tetraquark resonance\nwith quantum numbers $I(J^{P})=0(1^{-})$, which is based on antiheavy-antiheavy\nlattice QCD potentials, by including heavy quark spin effects via the mass\ndifference of the $B$ and the $B^{*}$ meson. This leads to a coupled channel\nSchr\\\"odinger equation, where the two channels correspond to $BB$ and\n$B^{*}B^{*}$, respectively. We search for $\\mbox{T}$ matrix poles in the\ncomplex energy plane, but do not find any indication for the existence of a\ntetraquark resonance in this refined coupled channel approach. We also vary the\nantiheavy-antiheavy potentials as well as the $b$ quark mass to further\nunderstand the dynamics of this four-quark system."
    },
    {
        "anchor": "A New Finite-lattice study of the Massive Schwinger Model: A new finite lattice calculation of the low lying bound state energies in the\nmassive Schwinger model is presented, using a Hamiltonian lattice formulation.\nThe results are compared with recent analytic series calculations in the low\nmass limit, and with a new higher order non-relativistic series which we\ncalculate for the high mass limit. The results are generally in good agreement\nwith these series predictions, and also with recent calculations by light cone\nand related techniques.",
        "positive": "On improvement of the axial-vector current with stabilised Wilson\n  fermions: We report on the determination of the improvement coefficient $c_{\\rm A}$ for\nthe non-singlet axial-vector current $A^{a}_{\\mu}(x)$ in the framework of\nstabilised Wilson-Clover fermions within three flavour lattice QCD. This is\ndone by requiring the PCAC relation to hold for two different pseudo-scalar\nstates. To generate these states, wavefunctions altering spatial structures on\nthe boundaries of a Schr\\\"odinger functional lattice are employed and some\nvariations of the (previously applied) wavefunction method are explored. The\nimprovement coefficient is determined on a few ensembles for a range of gauge\ncouplings that is potentially useful for future applications. Preliminary\nresults on the renormalisation constants $Z_{\\rm V}$ for the vector current and\n$Z_{\\rm A}$ for the axial-vector current are also presented."
    },
    {
        "anchor": "Self-Renormalization of Quasi-Light-Front Correlators on the Lattice: In applying large-momentum effective theory, renormalization of the Euclidean\ncorrelators in lattice regularization is a challenge due to linear divergences\nin the self-energy of Wilson lines. Based on lattice QCD matrix elements of the\nquasi-PDF operator at lattice spacing $a$= 0.03 fm $\\sim$ 0.12 fm with clover\nand overlap valence quarks on staggered and domain-wall sea, we design a\nstrategy to disentangle the divergent renormalization factors from finite\nphysics matrix elements, which can be matched to a continuum scheme at short\ndistance such as dimensional regularization and minimal subtraction. Our\nresults indicate that the renormalization factors are universal in the hadron\nstate matrix elements. Moreover, the physical matrix elements appear\nindependent of the valence fermion formulations. These conclusions remain valid\neven with HYP smearing which reduces the statistical errors albeit reducing\ncontrol of the renormalization procedure. Moreover, we find a large\nnon-perturbative effect in the popular RI/MOM and ratio renormalization scheme,\nsuggesting favor of the hybrid renormalization procedure proposed recently.",
        "positive": "Phase Transitions in Particle Physics -- Results and Perspectives from\n  Lattice Quantum Chromo-Dynamics: Phase transitions in a non-perturbative regime can be studied by ab initio\nLattice Field Theory methods. The status and future research directions for LFT\ninvestigations of Quantum Chromo-Dynamics under extreme conditions are\nreviewed, including properties of hadrons and of the hypothesized QCD axion as\ninferred from QCD topology in different phases. We discuss phase transitions in\nstrong interactions in an extended parameter space, and the possibility of\nmodel building for Dark Matter and Electro-Weak Symmetry Breaking.\nMethodological challenges are addressed as well, including new developments in\nArtificial Intelligence geared towards the identification of different phases\nand transitions."
    },
    {
        "anchor": "Bogoliubov transformations and fermion condensates in lattice field\n  theories: We apply generalized Bogoliubov transformations to the transfer matrix of\nrelativistic field theories regularized on a lattice. We derive the conditions\nthese transformations must satisfy to factorize the transfer matrix into two\nterms which propagate fermions and antifermions separately, and we solve the\nrelative equations under some conditions. We relate these equations to the\nsaddle point approximation of a recent bosonization method and to the\nFoldy-Wouthuysen transformations which separate positive from negative energy\nstates in the Dirac Hamiltonian.",
        "positive": "Non-perturbative computation of the strong coupling constant on the\n  lattice: We review the long term project of the ALPHA collaboration to compute in QCD\nthe running coupling constant and quark masses at high energy scales in terms\nof low energy hadronic quantities. The adapted techniques required to\nnumerically carry out the required multiscale non-perturbative calculation with\nour special emphasis on the control of systematic errors are summarized. The\ncomplete results in the two dynamical flavor approximation are reviewed and an\noutlook is given on the ongoing three flavor extension of the programme with\nimproved target precision."
    },
    {
        "anchor": "Measure in the 2D Regge quantum gravity: We propose a version of the 2D Regge calculus, in which the areas of all\ntriangles are equal to each other. In this discretization Lund - Regge measure\nover link lengths is simplified considerably. Contrary to the usual Regge\nmodels with Lund - Regge measure, where this measure is nonlocal and rather\ncomplicated, the models based on our approach can be investigated using the\nnumerical simulations in a rather simple way.",
        "positive": "Vortices, Confinement and Higgs fields: We review lattice evidence for the vortex mechanism of quark confinement and\nstudy the influence of charged matter fields on the vortex distribution."
    },
    {
        "anchor": "Finite temperature QCD with two flavors of dynamical quarks on 24^3*10\n  lattice: We present results obtained in QCD with two flavors of non-perturbatively\nimproved Wilson fermions at finite temperature on $16^3 \\times 8$ and $24^3\n\\times 10$ lattices. We determine the transition temperature in the range of\nquark masses $0.6<m_\\pi/m_\\rho<0.8$ at lattice spacing a$\\approx$0.1 fm and\nextrapolate the transition temperature to the continuum and to the chiral\nlimits.",
        "positive": "Benchmarking the Bayesian reconstruction of the non-perturbative heavy\n  $Q\\bar{Q}$ potential: The extraction of the finite temperature heavy quark potential from lattice\nQCD relies on a spectral analysis of the real-time Wilson loop. Through its\nposition and shape, the lowest lying spectral peak encodes the real and\nimaginary part of this complex potential. We benchmark this extraction strategy\nusing leading order hard-thermal loop (HTL) calculations. I.e. we analytically\ncalculate the Wilson loop and determine the corresponding spectrum. By fitting\nits lowest lying peak we obtain the real- and imaginary part and confirm that\nthe knowledge of the lowest peak alone is sufficient for obtaining the\npotential. We deploy a novel Bayesian approach to the reconstruction of\nspectral functions to HTL correlators in Euclidean time and observe how well\nthe known spectral function and values for the real and imaginary part are\nreproduced. Finally we apply the method to quenched lattice QCD data and\nperform an improved estimate of both real and imaginary part of the\nnon-perturbative heavy $Q\\bar{Q}$ potential."
    },
    {
        "anchor": "Quarkonium-Nucleus Bound States from Lattice QCD: Quarkonium-nucleus systems are composed of two interacting hadronic states\nwithout common valence quarks, which interact primarily through multi-gluon\nexchanges, realizing a color van der Waals force. We present lattice QCD\ncalculations of the interactions of strange and charm quarkonia with light\nnuclei. Both the strangeonium-nucleus and charmonium-nucleus systems are found\nto be relatively deeply bound when the masses of the three light quarks are set\nequal to that of the physical strange quark. Extrapolation of these results to\nthe physical light-quark masses suggests that the binding energy of charmonium\nto nuclear matter is B < 40 MeV.",
        "positive": "$D_s$ to $\u03c6$ and other transitions from lattice QCD: We have studied transitions between vector and pseudoscalar mesons using the\nHISQ action for the valence quarks. We have calculated all of the axial and\nvector form factors that appear in the decay rate for $D_s \\to \\phi \\ell \\nu$\nover the full $q^2$ range and compared them to the shape of the experimental\ndecay distributions. We use nonperturbatively normalised currents for the\nvector and axial vector currents. The same set up for the three point\ncorrelations functions also allow us to study radiative decays and we have\ncalculated the decay rate for $J/\\psi \\to \\eta_c \\gamma$."
    },
    {
        "anchor": "Scaling and confinement aspects of tadpole improved SU(2) lattice gauge\n  theory and its abelian projection: Using a tadpole improved SU(2) gluodynamics action, the nonabelian potential\nand the abelian potential after the abelian projection are computed. Rotational\ninvariance is found restored at coarse lattices both in the nonabelian theory\nand in the effective abelian theory resulting from maximal abelian projection.\nAsymptotic scaling is tested for the SU(2) string tension. Deviation of the\norder of $6%$ is found, for lattice spacings between 0.27 and 0.06 fm. Evidence\nfor asymptotic scaling and scaling of the monopole density in maximal abelian\nprojection is also seen, but not at coarse lattices. The scaling behavior is\ncompared with analyses of Wilson action results, using bare and renormalized\ncoupling schemes. Using extended monopoles, evidence is found that the gauge\ndependence of the abelian projection reflects short distance fluctuations, and\nmay thus disappear at large scales.",
        "positive": "Constraints for the QCD phase diagram from imaginary chemical potential: We present unambiguous evidence from lattice simulations of N_f=3 QCD for two\ntricritical points in the (T,m) phase diagram at fixed imaginary \\mu/T=i\\pi/3\nmod. 2\\pi/3, one in the light and one in the heavy quark regime. Together with\nsimilar results in the literature for N_f=2 this implies the existence of a\nchiral and of a deconfinement tricritical line at those values of imaginary\nchemical potentials. These tricritical lines represent the boundaries of the\nanalytically continued chiral and deconfinement critical surfaces,\nrespectively, which delimit the parameter space with first order phase\ntransitions. It is demonstrated that the shape of the deconfinement critical\nsurface is dictated by tricritical scaling and implies the weakening of the\ndeconfinement transition with real chemical potential. A qualitatively similar\neffect holds for the chiral critical surface."
    },
    {
        "anchor": "Temperature dependence of topological susceptibility using gradient flow: We study temperature dependence of the topological susceptibility with the\n$N_{f}=2+1$ flavors Wilson fermion. We have two major interests in this paper.\nOne is a comparison of gluonic and fermionic definitions of the topological\nsusceptibility. Two definitions are related by the chiral Ward-Takahashi\nidentity but their coincidence is highly non-trivial for the Wilson fermion. By\napplying the gradient flow both for the gauge and quark fields we find a good\nagreement of these two measurements. The other is a verification of a\nprediction of the dilute instanton gas approximation at low temperature region\n$T_{pc}< T<1.5T_{pc}$, for which we confirm the prediction that the topological\nsusceptibility decays with power $\\chi_{t}\\propto(T/T_{pc})^{-8}$ for three\nflavors QCD.",
        "positive": "Thermodynamics of SU(3) Lattice Gauge Theory: The pressure and the energy density of the $SU(3)$ gauge theory are\ncalculated on lattices with temporal extent $N_\\tau = 4$, 6 and 8 and spatial\nextent $N_\\sigma =16$ and 32. The results are then extrapolated to the\ncontinuum limit. In the investigated temperature range up to five times $T_c$\nwe observe a $15\\%$ deviation from the ideal gas limit. We also present new\nresults for the critical temperature on lattices with temporal extent $N_\\tau =\n8$ and 12. At the corresponding critical couplings the string tension is\ncalculated on $32^4$ lattices to fix the temperature scale. An extrapolation to\nthe continuum limit yields $T_c/\\sqrt{\\sigma} = 0.629(3)$. We furthermore\npresent results on the electric and magnetic condensates as well as the\ntemperature dependence of the spatial string tension. These observables suggest\nthat the temperature dependent running coupling remains large even at $T\\simeq\n5T_c$. For the spatial string tension we find $\\sqrt{\\sigma_s}/T = 0.566(13)\ng^2(T)$ with $g^2(5T_c) \\simeq 1.5$."
    },
    {
        "anchor": "Polyakov Loop Behavior in Non-Extensive SU(2) Lattice Gauge Theory: In order to come closer to a realistic model of high-energy collisions, we\nsimulate SU(2) lattice gauge theory under fluctuating temperature. The\nfluctuations are Euler-Gamma distributed, leading to a canonical state\nmaximizing the Renyi and Tsallis entropy formulas. We test the random lattice\nspacing method numerically on the Polyakov Loop expectation value. The critical\ncoupling and presumably also the critical deconfinement temperature shifts\nabout 30 per cent to higher values with a realistic degree of fluctuations.",
        "positive": "Charmonium mass splittings at the physical point: We present results from an ongoing study of mass splittings of the lowest\nlying states in the charmonium system. We use clover valence charm quarks in\nthe Fermilab interpretation, an improved staggered (asqtad) action for sea\nquarks, and the one-loop, tadpole-improved gauge action for gluons. This study\nincludes five lattice spacings, 0.15, 0.12, 0.09, 0.06, and 0.045 fm, with two\nsets of degenerate up- and down-quark masses for most spacings. We use an\nenlarged set of interpolation operators and a variational analysis that permits\nstudy of various low-lying excited states. The masses of the sea quarks and\ncharm valence quark are adjusted to their physical values. This large set of\ngauge configurations allows us to extrapolate results to the continuum physical\npoint and test the methodology."
    },
    {
        "anchor": "On color confinement: The status of the theory of color confinemnt is discussed.",
        "positive": "A Self Consistent Study of the Phase Transition in the Scalar\n  Electroweak Theory at Finite Temperature: We propose the study of the phase transition in the scalar electroweak theory\nat finite temperature by a two - step method. It combines i) dimensional\nreduction to a 3-dimensional {\\it lattice\\/} theory via perturbative blockspin\ntransformation, and ii) either further real space renormalization group\ntransformations, or solution of gap equations, for the 3d lattice theory. A gap\nequation can be obtained by using the Peierls inequality to find the best\nquadratic approximation to the 3d action. % This method avoids the lack of self\nconsistency of the usual treatments which do not separate infrared and\nUV-problems by introduction of a lattice cutoff. The effective 3d lattice\naction could also be used in computer simulations."
    },
    {
        "anchor": "Standard Model evaluation of $\\varepsilon_K$ using lattice QCD inputs\n  for $\\hat{B}_K$ and $V_{cb}$: We report the Standard Model evaluation of the indirect CP violation\nparameter $\\varepsilon_K$ using inputs determined from lattice QCD: the kaon\nbag parameter $\\hat{B}_K$, $\\xi_0$, $|V_{us}|$ from the $K_{\\ell 3}$ and\n$K_{\\mu 2}$ decays, and $|V_{cb}|$ from the axial current form factor for the\nexclusive decay $\\bar{B} \\to D^* \\ell \\bar{\\nu}$ at zero-recoil. The\ntheoretical expression for $\\varepsilon_K$ is thoroughly reviewed to give an\nestimate of the size of the neglected corrections, including long distance\neffects. The Wolfenstein parametrization $(|V_{cb}|, \\lambda, \\bar{\\rho},\n\\bar{\\eta})$ is adopted for CKM matrix elements which enter through the short\ndistance contribution of the box diagrams. For the central value, we take the\nUnitarity Triangle apex $(\\bar{\\rho}, \\bar{\\eta})$ from the angle-only fit of\nthe UTfit collaboration and use $V_{us}$ as an independent input to fix\n$\\lambda$. We find that the Standard Model prediction of $\\varepsilon_K$ with\nexclusive $V_{cb}$ (lattice QCD results) is lower than the experimental value\nby $3.4\\sigma$. However, with inclusive $V_{cb}$ (results of the heavy quark\nexpansion), there is no gap between the Standard Model prediction of\n$\\varepsilon_K$ and its experimental value. For the calculation of\n$\\varepsilon_K$, we perform the renormalization group running to obtain\n$\\eta_{cc}$ at next-to-next-to-leading-order; we find\n$\\eta_{cc}^\\mathrm{NNLO}=1.72(27)$.",
        "positive": "Strongly Interacting Higgs Sector in the Minimal Standard Model?: The triviality Higgs mass bound is studied with a higher derivative regulator\nin the spontaneously broken phase of the four dimensional O(4) symmetric scalar\nfield theory with quartic self-interaction. The phase diagram of the O(4) model\nis determined in a Monte Carlo simulation which interpolates between the\nhypercubic lattice regulator and the higher derivative regulator in continuum\nspace-time. The same method can be used to calculate the Higgs mass bound in\ncontinuum space-time. In a large-N analysis, when compared with a hypercubic\nlattice, we find a relative increase in the triviality bound of the higher\nderivative regulator suggesting a strongly interacting Higgs sector in the TeV\nregion with negligible dependence on regulator parameters. When the higher\nderivative regulator mass is brought close to the Higgs mass the model requires\na more elaborate analysis of complex ghost states in scattering amplitudes.\nPart Two of Extended UCSD-PTH 92-40"
    },
    {
        "anchor": "2D Potts Model Correlation Lengths: Numerical Evidence for $\u03be_o =\n  \u03be_d$ at $\u03b2_t$: We have studied spin-spin correlation functions in the ordered phase of the\ntwo-dimensional $q$-state Potts model with $q=10$, 15, and 20 at the\nfirst-order transition point $\\beta_t$. Through extensive Monte Carlo\nsimulations we obtain strong numerical evidence that the correlation length in\nthe ordered phase agrees with the exactly known and recently numerically\nconfirmed correlation length in the disordered phase: $\\xi_o(\\beta_t) =\n\\xi_d(\\beta_t)$. As a byproduct we find the energy moments in the ordered phase\nat $\\beta_t$ in very good agreement with a recent large $q$-expansion.",
        "positive": "Geometry of Reduced Supersymmetric 4D Yang-Mills Integrals: We study numerically the geometric properties of reduced supersymmetric\nnon-compact SU(N) Yang-Mills integrals in D=4 dimensions, for N = 2,3, ..., 8.\nWe show that in the range of large eigenvalues of the matrices A^mu, the\noriginal D-dimensional rotational symmetry is spontaneously broken and the\ndominating field configurations become one-dimensional, as anticipated by\nstudies of the underlying surface theory. We also discuss possible implications\nof our results for the IKKT model."
    },
    {
        "anchor": "Screening and confinement in U(1)^{N-1} Abelian effective theories: We discuss the effect of dynamical charged particles in U(1)^{N-1} Abelian\neffective theories of QCD. Screening and confinement at zero temperature are\nexplained qualitatively. The effect of dynamically charged particle is\nexpressed in terms of an effective action of integer electric currents. When a\nscreening is expected, the static potential shows a flattening in the\nlong-range region and a linear behavior in the intermediate region. We show why\nthe screening is better observed in the Polyakov-loop correlators than in the\nWilson loops. The breaking of the adjoint string is explained without the Z(N)\npicture.",
        "positive": "A novel approach to the study of conformality in the SU(3) theory with\n  multiple flavors: We investigate the transition between spontaneous chiral symmetry breaking\nand conformal behavior in the SU(3) theory with multiple fermion flavors. We\npropose a new strategy for studying this transition. Instead of changing the\nnumber of flavors, we lift the mass of a subset of the fermions, keeping the\nrest of the fermions near to the massless chiral limit in order to probe the\ntransition.\n  Dedicated to the 60th birthday of Academician Valery Rubakov."
    },
    {
        "anchor": "Efficiencies and optimization of HMC algorithms in pure gauge theory: As a prerequisite to dynamical fermion simulations a detailed study of\noptimal parameters and scaling behavior is conducted for the quenched\nSchr\\\"odinger functional at fixed renormalized coupling. We compare standard\nhybrid overrelaxation techniques with local and global hybrid Monte Carlo. Our\nefficiency measure is designed to be directly relevant for the strong coupling\nconstant as used by the ALPHA collaboration.",
        "positive": "Search for the IR fixed point in the Twisted Polyakov Loop scheme (II): We measure the renormalized coupling in the Twisted Polyakov loop scheme for\nSU(3) gauge theory coupled with $N_f=12$ fundamental fermions. To find the\ninfrared fixed point of this theory, we focus on the step scaling function for\nthe renormalized coupling. We take the continuum limit using the linear\nfunction of $(a/L)^2$ and a constant fit function. We find that there is a\nsizeable systematic error due to the choice of the continuum extrapolation\nfunction in the low energy region. We will give some directions to reduce the\nsystematic errors."
    },
    {
        "anchor": "Chiral symmetry of QCD with twelve light flavors: We study QCD with twelve light flavors at intermediate values of the bare\nlattice coupling. We contrast the results for the order parameter with\ndifferent theoretical models motivated by the physics of the Goldstone phase\nand of the symmetric phase, and we perform a model independent analysis of the\nmeson spectrum inspired by universal properties of chiral symmetry. Our\nanalysis favors chiral symmetry restoration.",
        "positive": "Comparing Wilson and Clover Quenched $SU(3)$ Spectroscopy with an\n  Improved Gauge Action: We present results of quenched $SU(3)$ hadron spectroscopy comparing\n$\\order(a)$ improved Wilson (Clover) fermions with conventional Wilson\nfermions. The configurations were generated using an $\\order(a^2)$ improved\n6-link $SU(3)$ pure gauge action at $\\beta$'s corresponding to lattice spacings\nof $0.15$, $0.18$, $0.20$, $0.33$, and $0.43$ fm. We find evidence that\nfermionic scaling violations are consistent with $\\order(a^2)$ for Clover and\n$\\order(a)$ with a nonnegligible $\\order(a^2)$ term for standard Wilson\nfermions. This latter mixed ansatz makes a reliable continuum extrapolation\nproblematic for Wilson fermions. We also find that the slope of the scaling\nviolations is roughly $250 MeV$ for both Wilson and Clover fermions."
    },
    {
        "anchor": "String tension scaling in models of the confined phase: We introduce a D-dimensional Hamiltonian formalism for the study of Polyakov\nloop models of finite temperature gauge theories in D+1 dimensions. Polyakov\nloop string tensions are obtained from energy eigenstates of the Hamiltonian.\nFor D=1, the gauge theory reduces to quantum mechanics on the gauge group; for\nD>1, the Hamiltonian includes hopping terms that link sites on the transverse\nlattice. The deconfined phase is associated with a ground state which breaks\nZ(N) symmetry, and Svetitsky-Yaffe critical universality emerges naturally for\nD>1. A minimal model is proposed which naturally reproduces approximate Casimir\nscaling for a range of couplings. Different classes of potentials lead to\ndifferent pictures of how confinement is realized. Such potential energy terms\nalso modify string tension scaling laws, as we demonstrate using two\npotentials: one representing the perturbative thermal contributions from\ngluons, and the other arising from magnetic monopoles in certain confining\nsupersymmetric theories.",
        "positive": "Bound States of (Anti-)Scalar-Quarks in SU(3)_c Lattice QCD: Light scalar-quarks \\phi (colored scalar particles or idealized diquarks) and\ntheir color-singlet hadronic states are studied with quenched SU(3)_c lattice\nQCD in terms of mass generation. We investigate ``scalar-quark mesons''\n\\phi^\\dagger \\phi and ``scalar-quark baryons'' \\phi\\phi\\phi as the bound states\nof scalar-quarks \\phi. We also investigate the bound states of scalar-quarks\n\\phi and quarks \\psi, i.e., \\phi^\\dagger \\psi, \\psi\\psi\\phi and \\phi\\phi\\psi,\nwhich we name ``chimera hadrons''. All the new-type hadrons including \\phi are\nfound to have a large mass due to large quantum corrections by gluons, even for\nzero bare scalar-quark mass m_\\phi=0 at a^{-1}\\sim 1{\\rm GeV}. We conjecture\nthat all colored particles generally acquire a large effective mass due to\ndressed gluon effects."
    },
    {
        "anchor": "Continuum limit of the spectrum of the hadronic string: We look at the continuum limit of the two universal predictions of the\nhadronic string theory namely the Luescher term and the energy difference\nbetween successive energy states in three dimensional SU(2) lattice gauge\ntheory using Wilson loops and Polyakov loop correlators. We also compare our\nsimulation data with the theoretical predictions in hep-th/0406205.",
        "positive": "Scaling and Goldstone effects in a QCD with two flavours of adjoint\n  quarks: We study QCD with two Dirac fermions in the adjoint representation at finite\ntemperature by Monte Carlo simulations.In such a theory the deconfinement and\nchiral phase transitions occur at different temperatures. We locate the second\norder chiral transition point at beta_c=5.624(2) and show that the scaling\nbehaviour of the chiral condensate in the vicinity of beta_c is in full\nagreeement with that of the 3d O(2) universality class, and to a smaller extent\ncomparable to the 3d O(6) class. From the previously determined first order\ndeconfinement transition point beta_d=5.236(3) and the two-loop beta function\nwe find the ratio T_c/T_d = 7.8(2). In the region between the two phase\ntransitions we explicitly confirm the quark mass dependence of the chiral\ncondensate which is expected due to the existence of Goldstone modes like in 3d\nO(N) spin models. At the deconfinement transition the condensate shows a gap,\nand below beta_d, it is nearly mass-independent for fixed beta."
    },
    {
        "anchor": "Tadpole-Improved Perturbation Theory for Heavy-Light Lattice Operators: Lattice calculations of matrix elements involving heavy-light quark bilinears\nare of interest in calculating a variety of properties of B and D mesons,\nincluding decay constants and mixing parameters. A large source of uncertainty\nin the determination of these properties has been uncertainty in the\nnormalization of the lattice-regularized operators that appear in the matrix\nelements. Tadpole-improved perturbation theory, as formulated by Lepage and\nMackenzie, promises to reduce these uncertainties below the ten per cent level\nat one-loop. In this paper we study this proposal as it applies to\nlattice-regularized heavy-light operators. We consider both the commonly used\nzero-distance bilinear and the distance-one point-split operator. A\nself-contained section on the application of these results is included. The\ncalculation reduces the value of $f_B$ obtained from lattice calculations using\nthe heavy quark effective theory.",
        "positive": "Two-Color QCD with Non-zero Chiral Chemical Potential: The phase diagram of two-color QCD with non-zero chiral chemical potential is\nstudied by means of lattice simulation. We focus on the influence of a chiral\nchemical potential on the confinement/deconfinement phase transition and the\nbreaking/restoration of chiral symmetry. The simulation is carried out with\ndynamical staggered fermions without rooting. The dependences of the Polyakov\nloop, the chiral condensate and the corresponding susceptibilities on the\nchiral chemical potential and the temperature are presented. The critical\ntemperature is observed to increase with increasing chiral chemical potential."
    },
    {
        "anchor": "Continuing Progress on a Lattice QCD Software Infrastructure: We report on the progress of the software effort in the QCD Application Area\nof SciDAC. In particular, we discuss how the software developed under SciDAC\nenabled the aggressive exploitation of leadership computers, and we report on\nprogress in the area of QCD software for multi-core architectures.",
        "positive": "Radiative corrections to semileptonic decay rates: We discuss the theoretical framework required for the computation of\nradiative corrections to semileptonic decay rates in lattice simulations, and\nin particular to those for $K_{\\ell3}$ decays. This is an extension of the\nframework we have developed and successfully implemented for leptonic decays.\nNew issues which arise for semileptonic decays, include the presence of\nunphysical terms which grow exponentially with the time separation between the\ninsertion of the weak Hamiltonian and the sink for the final-state meson-lepton\npair. Such terms must be identified and subtracted. We discuss the cancellation\nof infrared divergences and show that, with the QED$_\\mathrm{\\,L}$ treatment of\nthe zero mode in the photon propagator, the $O(1/L)$ finite-volume corrections\nare \"universal\". These corrections however, depend not only on the semileptonic\nform factors $f^\\pm(q^2)$ but also on their derivatives $df^\\pm/dq^2$. (Here\n$q$ is the momentum transfer between the initial and final state mesons.) We\nexplain the perturbative calculation which would need to be performed to\nsubtract the $O(1/L)$ finite-volume effects."
    },
    {
        "anchor": "What is QFT? Resurgent trans-series, Lefschetz thimbles, and new exact\n  saddles: This is an introductory level review of recent applications of resurgent\ntrans-series and Picard-Lefschetz theory to quantum mechanics and quantum field\ntheory. Resurgence connects local perturbative data with global topological\nstructure. In quantum mechanical systems, this program provides a constructive\nrelation between different saddles. For example, in certain cases it has been\nshown that all information around the instanton saddle is encoded in\nperturbation theory around the perturbative saddle. In quantum field theory,\nsuch as sigma models compactified on a circle, neutral bions provide a\nsemi-classical interpretation of the elusive IR-renormalon, and fractional kink\ninstantons lead to the non-perturbatively induced gap, of order of the strong\nscale. In the path integral formulation of quantum mechanics, saddles must be\nfound by solving the holomorphic Newton's equation in the inverted\n(holomorphized) potential. Some saddles are complex, multi-valued, and even\nsingular, but of finite action, and their inclusion is strictly necessary to\nprevent inconsistencies. The multi-valued saddles enter either via resurgent\ncancellations, or their phase is tied with a hidden topological angle. We\nemphasize the importance of the destructive/constructive interference effects\nbetween equally dominant saddles in the Lefschetz thimble decomposition. This\nis especially important in the context of the sign problem.",
        "positive": "Matrix Product States for Lattice Field Theories: The term Tensor Network States (TNS) refers to a number of families of states\nthat represent different ans\\\"atze for the efficient description of the state\nof a quantum many-body system. Matrix Product States (MPS) are one particular\ncase of TNS, and have become the most precise tool for the numerical study of\none dimensional quantum many-body systems, as the basis of the Density Matrix\nRenormalization Group method. Lattice Gauge Theories (LGT), in their\nHamiltonian version, offer a challenging scenario for these techniques. While\nthe dimensions and sizes of the systems amenable to TNS studies are still far\nfrom those achievable by 4-dimensional LGT tools, Tensor Networks can be\nreadily used for problems which more standard techniques, such as Markov chain\nMonte Carlo simulations, cannot easily tackle. Examples of such problems are\nthe presence of a chemical potential or out-of-equilibrium dynamics. We have\nexplored the performance of Matrix Product States in the case of the Schwinger\nmodel, as a widely used testbench for lattice techniques. Using finite-size,\nopen boundary MPS, we are able to determine the low energy states of the model\nin a fully non-perturbative manner and to accurately extract the mass spectrum.\nIn this work we extend the analysis to the determination of the chiral\ncondensate, both for massless and massive fermions. The method allows for\naccurate finite size and continuum limit extrapolations and produces remarkably\nprecise results, thus showing the feasibility of these techniques for gauge\ntheory problems."
    },
    {
        "anchor": "Meron-cluster algorithms and chiral symmetry breaking in a (2+1)-d\n  staggered fermion model: The recently developed Meron-Cluster algorithm completely solves the\nexponentially difficult sign problem for a number of models previously\ninaccessible to numerical simulation. We use this algorithm in a high-precision\nstudy of a model of N=1 flavor of staggered fermions in (2+1)-dimensions with a\nfour-fermion interaction. This model cannot be explored using standard\nalgorithms. We find that the Z(2) chiral symmetry of this model is\nspontaneously broken at low temperatures and that the finite-temperature chiral\nphase transition is in the universality class of the 2-d Ising model, as\nexpected.",
        "positive": "Sampling versus Blocking: The idea of blocking in configuration space has played an important role in\nthe development of the RG ideas. However, despite being half a century old and\nhaving had a huge intellectual impact, generic numerical methods to perform\nblocking for lattice models have progressed more slowly than sampling methods.\nBlocking may be essential to deal with near conformal situations. Typically,\nblocking methods have smaller statistical errors but larger systematic errors\nthan sampling methods. This situation is evolving with recent developments\nbased on the Tensor RG (TRG) method. We report recent results for spin and\ngauge lattice models obtained with this new method regarding searches for fixed\npoints, calculations of critical exponents and resolutions of sign problems. An\ninteresting model for comparison is the 2-dimensional O(2) model with a\nchemical potential which has a sign problem with conventional Monte Carlo but\nallows sampling with the worm algorithm and blocking with various TRG\nformulations. We compare the efficiency and accuracy of these two methods."
    },
    {
        "anchor": "Towards Critical Physics in 2+1d with U(2N)-Invariant Fermions: Interacting theories of N relativistic fermion flavors in reducible spinor\nrepresentations in 2+1 spacetime dimensions are formulated on a lattice using\ndomain wall fermions (DWF), for which a U(2N) global symmetry is recovered in\nthe limit that the wall separation $L_s$ is made large. The Gross-Neveu (GN)\nmodel is studied in the large-N limit and an exponential acceleration of\nconvergence to the large-$L_s$ limit is demonstrated if the usual\nparity-invariant mass $m\\bar\\psi\\psi$ is replaced by the U(2N)-equivalent\n$im_3\\bar\\psi\\gamma_3\\psi$. The GN model and two lattice variants of the\nThirring model are simulated for N = 2 using a hybrid Monte Carlo algorithm,\nand studies made of the symmetry-breaking bilinear condensate and its\nassociated susceptibility, the axial Ward identity, and the mass spectrum of\nboth fermion and meson excitations. Comparisons are made with existing results\nobtained using staggered fermions. For the GN model a symmetry-breaking phase\ntransition is observed, the Ward identity is recovered, and the spectrum found\nto be consistent with large-N expectations. There appears to be no obstruction\nto the study of critical UV fixed-point physics using DWF. For the Thirring\nmodel the Ward identity is not recovered, the spectroscopy measurements are\ninconclusive, and no symmetry breaking is observed all the way up to the\neffective strong coupling limit. This is consistent with a critical Thirring\nflavor number $N_c<2$, contradicting earlier staggered fermion results.",
        "positive": "Algorithms for dynamical overlap fermions: An overview of the current status of algorithmic approaches to dynamical\noverlap fermions is given. In particular the issue of changing the topological\nsector is discussed."
    },
    {
        "anchor": "Domain decomposition improvement of quark propagator estimation: Applying domain decomposition to the lattice Dirac operator and the\nassociated quark propagator, we arrive at expressions which, with the proper\ninsertion of random sources therein, can provide improvement to the estimation\nof the propagator. Schemes are presented for both open and closed (or loop)\npropagators. In the end, our technique for improving open contributions is\nsimilar to the ``maximal variance reduction'' approach of Michael and Peisa,\nbut contains the advantage, especially for improved actions, of dealing\ndirectly with the Dirac operator. Using these improved open propagators for the\nChirally Improved operator, we present preliminary results for the static-light\nmeson spectrum. The improvement of closed propagators is modest: on some\nconfigurations there are signs of significant noise reduction of disconnected\ncorrelators; on others, the improvement amounts to a smoothening of the same\ncorrelators.",
        "positive": "Singly and Doubly Charmed J=1/2 Baryon Spectrum from Lattice QCD: We compute the masses of the singly and doubly charmed baryons in full QCD\nusing the relativistic Fermilab action for the charm quark. For the light\nquarks we use domain-wall fermions in the valence sector and improved\nKogut-Susskind sea quarks. We use the low-lying charmonium spectrum to tune our\nheavy-quark action and as a guide to understanding the discretization errors\nassociated with the heavy quark. Our results are in good agreement with\nexperiment within our systematics. For the \\Xi_{cc}, we find the\nisospin-averaged mass to be M_{\\Xi_{cc}} = 3665 +/- 17 +/- 14 +0 -78 MeV; the\nthree given uncertainties are statistical, systematic and an estimate of\nlattice discretization errors, respectively. In addition, we predict the mass\nsplitting of the (isospin-averaged) spin-1/2 \\Omega_{cc} with the \\Xi_{cc} to\nbe M_{\\Omega_{cc}} - M_{\\Xi_{cc}} = 98 +/- 9 +/- 22 +/- 13 MeV (in this mass\nsplitting, the leading discretization errors are also suppressed by SU(3)\nsymmetry). Combining this splitting with our determination of M_{\\Xi_{cc}}\nleads to our prediction of the spin-1/2 \\Omega_{cc} mass, M_{\\Omega_{cc}} =\n3763 +/- 19 +/- 26 +13 -79 MeV."
    },
    {
        "anchor": "Dynamical simulation of lattice 4d N=1 SYM: The lattice provides a powerful tool to non-perturbatively investigate\nstrongly coupled supersymmetric Yang-Mills (SYM) theories. The pure SU(2) SYM\ntheory with one supercharge is simulated on large lattices with small Majorana\ngluino masses down to about $am_{\\tilde g}=0.068$ with lattice spacing $a\\simeq\n0.125$ fm. The gluino dynamics is simulated by the Two-Step Multi-Boson (TSMB)\nand the Two-Step Polynomial Hybrid Monte Carlo (TS-PHMC) algorithms.\nSupersymmetry (SUSY) is broken explicitly by the lattice and the Wilson term\nand softly by the presence of a non-vanishing gluino mass. However, the\nrecovery of SUSY is expected in the infinite volume continuum limit by tuning\nthe bare parameters to the SUSY point in the parameter space. This scenario is\nstudied by the determination of the low-energy mass spectrum and by means of\nlattice SUSY Ward-Identities (WIs).",
        "positive": "QCD mesonic screening masses up to high temperatures: We discuss a strategy to study non-perturbatively QCD up to very high\ntemperatures by Monte Carlo simulations on the lattice. It allows not only the\nthermodynamic properties of the theory but also other interesting thermal\nfeatures to be investigated. As a first concrete application, we compute the\nflavour non-singlet mesonic screening masses and we present the results of\nMonte Carlo simulations at 12 temperatures covering the range from T $\\sim$ 1\nGeV up to $\\sim$ 160 GeV in the theory with three massless quarks. On the one\nside, chiral symmetry restoration manifests itself in our results through the\ndegeneracy of the vector and the axial vector channels and of the scalar and\nthe pseudoscalar ones, and, on the other side, we observe a clear splitting\nbetween the vector and the pseudoscalar screening masses up to the highest\ninvestigated temperature. A comparison with the high-temperature effective\ntheory shows that the known one-loop order in the perturbative expansion does\nnot provide a satisfactory description of the non-perturbative data up to the\nhighest temperature considered."
    },
    {
        "anchor": "Chiral properties of domain-wall fermions from eigenvalues of 4\n  dimensional Wilson-Dirac operator: We investigate chiral properties of the domain-wall fermion (DWF) system by\nusing the four-dimensional hermitian Wilson-Dirac operator. We first derive a\nformula which connects a chiral symmetry breaking term in the five dimensional\nDWF Ward-Takahashi identity with the four dimensional Wilson-Dirac operator,\nand simplify the formula in terms of only the eigenvalues of the operator,\nusing an ansatz for the form of the eigenvectors. For a given distribution of\nthe eigenvalues, we then discuss the behavior of the chiral symmetry breaking\nterm as a function of the fifth dimensional length. We finally argue the chiral\nproperty of the DWF formulation in the limit of the infinite fifth dimensional\nlength, in connection with spectra of the hermitian Wilson-Dirac operator in\nthe infinite volume limit as well as in the finite volume.",
        "positive": "Analytic progress on exact lattice chiral symmetry: Theoretical issues of exact chiral symmetry on the lattice are discussed and\nrelated recent works are reviewed. For chiral theories, the construction with\nexact gauge invariance is reconsidered from the point of view of domain wall\nfermion. The issue in the construction of electroweak theory is also discussed.\nFor vector-like theories, we discuss unitarity (positivity), Hamiltonian\napproach, and several generalizations of the Ginsparg-Wilson relation\n(algebraic and odd-dimensional)."
    },
    {
        "anchor": "O(N) and RP^{N-1} Models in Two Dimensions: I provide evidence that the 2D $RP^{N-1}$ model for $N \\ge 3$ is equivalent\nto the $O(N)$-invariant non-linear $\\sigma$-model in the continuum limit. To\nthis end, I mainly study particular versions of the models, to be called\nconstraint models. I prove that the constraint $RP^{N-1}$ and $O(N)$ models are\nequivalent for sufficiently weak coupling. Numerical results for their\nstep-scaling function of the running coupling $\\bar{g}^2= m(L) L$ are\npresented. The data confirm that the constraint $O(N)$ model is in the samei\nuniversality class as the $O(N)$ model with standard action. I show that the\ndifferences in the finite size scaling curves of $RP^{N-1}$i and $O(N)$ models\nobserved by Caracciolo et al. can be explained as a boundary effect. It is\nconcluded, in contrast to Caracciolo et al., that $RP^{N-1}$ and $O(N)$ models\nshare a unique universality class.",
        "positive": "Semileptonic B Decays from an NRQCD/D234 Action: Semileptonic, B --> pi, l nubar, decays are studied on quenched anisotropic\nlattices using tree-level tadpole improved Symanzik glue, NRQCD heavy quark and\nD234 light quark actions. Constrained fitting methods are applied to extract\ngroundstate contributions to two-point and three-point correlators. We agree\nwith previous lattice determinations of the form factors. The major source of\nsystematic error here, as in previous work, comes from the chiral extrapolation\nto the physical pion mass. Future calculations must work at lighter quark\nmasses to resolve this."
    },
    {
        "anchor": "The gauged Nambu - Jona Lasinio model: a mean field calculation with non\n  mean field exponents: We analyse the phase diagram of the lattice gauged Nambu-Jona Lasinio model\nwith the help of a mean field approximation plus numerical simulations. We find\na phase transition line in the coupling parameters space separating the\nchirally broken phase from the symmetric phase, which is in good qualitative\nagreement with results obtained in the quenched-ladder approximation. The mean\nfield approximation relates the critical exponents along the continuous phase\ntransition line with the mass dependence of the chiral condensate in the\nCoulomb phase of standard noncompact $QED$. Our numerical results for\nnoncompact $QED$ strongly suggest non mean field exponents along the critical\nline.",
        "positive": "Focusing on the Fixed Point of 4D Simplicial Gravity: Our earlier renormalization group analysis of simplicial gravity is extended.\nA high statistics study of the volume and coupling constant dependence of the\ncumulants of the node distribution is carried out. It appears that the phase\ntransition of the theory is of first order, contrary to what is generally\nbelieved."
    },
    {
        "anchor": "K semileptonic form factor with HISQ fermions at the physical point: We present results for the form factor $f_+^{K \\pi}(0)$, needed to extract\nthe CKM matrix element $|V_{us}|$ from experimental data on semileptonic $K$\ndecays, on the HISQ $N_f=2+1+1$ MILC configurations. The HISQ action is also\nused for the valence sector. The data set used for our final result includes\nthree different values of the lattice spacing and data at the physical light\nquark masses. We discuss the error budget and how this calculation improves on\nour previous determination of $f_+^{K \\pi}(0)$ on the asqtad $N_f=2+1$ MILC\nconfigurations.",
        "positive": "Towards a reliable lower bound on the location of the critical endpoint: We perform the first direct determination of the position of the leading\nsingularity of the pressure in the complex chemical potential $\\mu_B$ plane in\nlattice QCD using numerical simulations with 2-stout improved rooted staggered\nfermions. This provides a direct determination of the radius of convergence of\nthe Taylor expansion of the pressure that does not rely on a finite-order\ntruncation of the expansion. The analyticity issues in the complex $\\mu_B$\nplane of the grand canonical partition function of QCD with rooted staggered\nfermions are solved with a careful redefinition of the fermion determinant that\nmakes it a polynomial in the fugacity on any finite lattice, without changing\nthe continuum limit of the observables. By performing a finite volume scaling\nstudy at a single coarse lattice spacing, we show that the limiting singularity\nis not on the real line in the thermodynamic limit, thus showing that the\nradius of convergence of the Taylor expansion gives a lower bound on the\nlocation of a possible phase transition. In the vicinity of the crossover\ntemperature at zero chemical potential, the radius of convergence turns out to\nbe $\\mu_B/T \\approx 2$ and roughly temperature independent."
    },
    {
        "anchor": "Status of the CP-PACS Project: The CP-PACS computer with a peak speed of 300 Gflops was completed in March\n1996 and has started to operate. We describe the final specification and the\nhardware implementation of the CP-PACS computer, and its performance for QCD\ncodes. A plan of the grade-up of the computer scheduled for fall of 1996 is\nalso given.",
        "positive": "An overview of the QCD phase diagram at finite $T$ and $\u03bc$: In recent years there has been much progress on the investigation of the QCD\nphase diagram with lattice QCD. This talk will focus on the developments in the\nlast few years. Especially the addition of external influences and extended\nranges of $T$ and $\\mu$ yield an increasing number of interesting results, a\nsubset of which will be discussed. Many of these conditions are important for\nthe understanding of both the QCD transition in the early universe and heavy\nion collision experiments which are conducted for example at the LHC and RHIC.\nThis offers many exciting opportunities for comparisons between theory and\nexperiment."
    },
    {
        "anchor": "Confinement and the center of the gauge group: The question of the role of the center of the gauge group in the phenomenon\nof confinement in Yang-Mills theory is addressed. The investigation is\nperformed from the most general perspective of considering all possible choices\nfor the gauge symmetry group. In this context, an interesting role is played by\nG(2) Yang-Mills theory: the simplest pure gauge theory with a trivial center\nand without 't Hooft flux vortices. Numerical simulations show the presence of\na first order finite temperature deconfinement phase transition in G(2)\nYang-Mills theory in (3+1) dimensions. Interestingly, the G(2) gauge symmetry\ncan be broken to an SU(3) subgroup by the Higgs mechanism. We investigate the\nrelation between the deconfinement phase transition in G(2) and SU(3)\nYang-Mills theories by numerical simulations in the G(2) gauge-Higgs system.",
        "positive": "Exploring the chiral singularities of two color lattice QCD at strong\n  coupling: We use a modified directed path algorithm to study the finite temperature\nchiral singularities of two color lattice QCD with staggered fermions at strong\ncoupling. Our lattice calculations are done at a fixed finite temperature in\nthe broken phase with a variety of different quark masses. We find that to the\nlowest order, the behavior of our observables, namely the condensates and the\ndecay constants are all consistent with the predictions of the low energy\neffective theory of our model. We further notice that in order to see\nconsistency, the quark masses used in our lattice calculations need to be quite\nsmall than typically used."
    },
    {
        "anchor": "Deconfined SU(2) phase with a massive vector boson triplet: We introduce a model of SU(2) and U(1) vector fields with a local U(2)\nsymmetry. Its action can be obtained in the London limit of a gauge invariant\nregularization involving two scalar fields. Evidence from lattice simulations\nof the model supports a (zero temperature) SU(2) deconfining phase transition\nthrough breaking of the SU(2) center symmetry, and a massive vector boson\ntriplet is found in the deconfined phase.",
        "positive": "Two- and three-point functions at criticality: Monte Carlo simulations\n  of the improved three-dimensional Blume-Capel model: We compute two- and three-point functions at criticality for the\nthree-dimensional Ising universality class. To this end we simulate the\nimproved Blume-Capel model at the critical temperature on lattices of a linear\nsize up to $L=1600$. As check also simulations of the spin-1/2 Ising model are\nperformed. We find $f_{\\sigma \\sigma \\epsilon} = 1.051(1)$ and $f_{\\epsilon\n\\epsilon \\epsilon} =1.533(5)$ for operator product expansion coefficients.\nThese results are consistent with but less precise than those recently obtained\nby using the bootstrap method. An important ingredient in our simulations is a\nvariance reduced estimator of $N$-point functions. Finite size corrections\nvanish with $L^{-\\Delta_{\\epsilon}}$, where $L$ is the linear size of the\nlattice and $\\Delta_{\\epsilon}$ is the scaling dimension of the leading\n$Z_2$-even scalar $\\epsilon$."
    },
    {
        "anchor": "On Nambu Monopole Dynamics in the SU(2) Lattice Higgs Model: It is shown that the SU(2) Higgs model on a lattice is equivalent to the\nGeorgi--Glashow model in the limit of a small coupling constant between the\nHiggs and gauge fields. It can therefore be concluded that the transition\nbetween the confinement and symmetric phases in the 3+1 dimensional SU(2) Higgs\nmodel at finite temperature is accompanied by condensation of Nambu monopoles.",
        "positive": "Chiral gauge theories on the lattice and restoration of gauge symmetry: We investigate a proposal for the construction of models with chiral fermions\non the lattice using staggered fermions. In this approach the gauge invariance\nis broken by the coupling of the staggered fermions to the gauge fields. We aim\nat a dynamical restoration of the gauge invariance in the full quantum model.\nIf the gauge symmetry breaking (SB) is not too severe, this procedure could\nlead in the continuum limit to the desired gauge invariant chiral gauge theory."
    },
    {
        "anchor": "On the application of Effective Field Theory to finite-volume effects in\n  $a_\u03bc^{\\rm HVP}$: One of the more important systematic effects affecting lattice computations\nof the hadronic vacuum polarization contribution to the anomalous magnetic\nmoment of the muon, $a_\\mu^{\\rm HVP}$, is the distortion due to a finite\nspatial volume. In order to reach sub-percent precision, these effects need to\nbe reliably estimated and corrected for, and one of the methods that has been\nemployed for doing this is finite-volume chiral perturbation theory. In this\npaper, we argue that finite-volume corrections to $a_\\mu^{\\rm HVP}$ can, in\nprinciple, be calculated at any given order in chiral perturbation theory. More\nprecisely, once all low-energy constants needed to define the Effective Field\nTheory representation of $a_\\mu^{\\rm HVP}$ in infinite volume are known to a\ngiven order, also the finite-volume corrections can be predicted to that order\nin the chiral expansion.",
        "positive": "Better Domain-Wall Fermions: We discuss two modifications of domain-wall fermions, aimed to reduce the\nchiral-symmetry violations presently encountered in numerical simulations."
    },
    {
        "anchor": "A nonlocal discretization of fields: A nonlocal method to obtain discrete classical fields is presented. This\ntechnique relies on well-behaved matrix representations of the derivatives\nconstructed on a non--equispaced lattice. The drawbacks of lattice theory like\nthe fermion doubling or the breaking of chiral symmetry for the massless case,\nare absent in this method.",
        "positive": "Nonuniformity of the $1/N$ Expansion for Two-Dimensional $O(N)$ Models: We point out that the $1/N$ expansion, which is widely invoked to infer\nproperties of the $2D$ $O(N)$ models, is nonuniform in the temperature, i.e.\nwith decreasing temperature the $1/N$ expansion truncated at a fixed order\ndeviates more and more from the true answer. This fact precludes the use of the\nexpansion to deduce low temperature properties such as asymptotic scaling for\nthose models. By contrast, in the $1D$ $O(N)$ chains, there are no signs of\nsuch a nonuniformity."
    },
    {
        "anchor": "The effects of flavour symmetry breaking on hadron matrix elements: By considering a flavour expansion about the SU(3)-flavour symmetric point,\nwe investigate how flavour-blindness constrains octet baryon matrix elements\nafter SU(3) is broken by the mass difference between the strange and light\nquarks. We find the expansions to be highly constrained along a mass trajectory\nwhere the singlet quark mass is held constant, which proves beneficial for\nextrapolations of 2+1 flavour lattice data to the physical point. We\ninvestigate these effects numerically via a lattice calculation of the\nflavour-conserving and flavour-changing matrix elements of the vector and axial\noperators between octet baryon states.",
        "positive": "Chiral perturbation theory for the Wilson lattice action: We extend chiral perturbation theory to include linear dependence on the\nlattice spacing $a$ for the Wilson action. The perturbation theory is written\nas a double expansion in the small quark mass $m_q$ and lattice spacing $a$. We\npresent formulae for the mass and decay constant of a flavor-non-singlet meson\nin this scheme to order $a$ and $m_q^2$. The extension to the partially\nquenched theory is also described."
    },
    {
        "anchor": "Monte Carlo Studies of Two-Dimensional Systems with a $\u03b8$ Term: A $\\theta$ term, which couples to topological charge, is added to the\ntwo-dimensional lattice CP^3 model and U(1) gauge theory. Monte Carlo\nsimulations are performed and compared to strong-coupling character expansions.\nIn certain instances, a flattening behavior occurs in the free-energy at\nsufficiently large $\\theta$, but the effect is an artifact of the simulation\nmethods.",
        "positive": "Exploring the role of the charm quark in the $\u0394I=1/2$ rule: We study the dependence on the charm quark mass of the leading-order\nlow-energy constants of the $\\Delta S=1$ effective Hamiltonian, with the aim of\nelucidating the role of the charm mass scale in the $\\Delta I=1/2$ rule for\n$K\\to\\pi\\pi$ decay. To that purpose, finite-volume Chiral Perturbation Theory\npredictions are matched to QCD simulations, performed in the quenched\napproximation with overlap fermions and $m_u=m_d=m_s$. Light quark masses range\nbetween a few MeV up to around one third of the physical strange mass, while\ncharm masses range between $m_u$ and a few hundred MeV. Novel variance\nreduction techniques are used to obtain a signal for penguin contractions in\ncorrelation functions involving four-fermion operators. The important role\nplayed by the subtractions required to construct renormalised amplitudes for\n$m_c \\neq m_u$ is discussed in detail. We find evidence that the moderate\nenhancement of the $\\Delta I=1/2$ amplitude previously found in the GIM limit\n$m_c=m_u$ increases only slightly as $m_c$ abandons the light quark regime.\nHints of a stronger enhancement for even higher values of $m_c$ are also found,\nbut their confirmation requires a better understanding of the subtraction\nterms."
    },
    {
        "anchor": "SU(3)-breaking effects in hyperon semileptonic decays: We present the first quenched lattice QCD study of all the vector and axial\nform factors relevant for the hyperon semileptonic decay Sigma- -> n l nu.",
        "positive": "Search for the H-Dibaryon in two flavor Lattice QCD: We present preliminary results from a lattice QCD calculation of the\nH-dibaryon using two flavors of $\\mathcal{O}(a)$ improved Wilson fermions. We\nemploy local six-quark interpolating operators at the source with a combination\nof local six-quark and two-baryon operators at the sink with the appropriate\nquantum numbers of the H-dibaryon and its coupling to the two-baryon channels.\nWe find that the two-baryon operators provide an improved overlap onto the\nground state in comparison to the local six-quark operators. We also apply\nL\\\"uscher's finite volume formalism to obtain information on the nature of the\ninfinite-volume interaction of two particles. Further, the momentum projection\nto three moving frames enables the isolation of the pole in the infinite-volume\nscattering amplitude. Preliminary results at pion masses of 450 MeV and 1 GeV\nclearly indicate the presence of states below the $\\Lambda \\Lambda$ threshold\nwhile a finite-volume analysis fails to conclusively show the existence of an\ninfinite-volume bound state."
    },
    {
        "anchor": "Finite-group gauge theories on lattices as Hamiltonian systems with\n  constraints: In this work, we present a brief but insightful overview of the gauge\ntheories, which are defined on $ n $-dimensional lattices by using finite gauge\ngroups, in order to show how they can be interpreted as a Hamiltonian system\nwith constraints, analogous to what happens with the classical (continuous)\ngauge (field) theories. As this interpretation is not usually explored in the\nliterature that discusses/introduces the concept of lattice gauge theory, but\nsome recent works have been exploring Hamiltonian models in order to support\nsome kind of quantum computation, we use this interpretation to, for example,\npresent a brief geometric view of one class of these models: the Kitaev Quantum\nDouble Models.",
        "positive": "Confinement in QCD: Results and Open Problems: Progress is reviewed in the understanding of color confinement ."
    },
    {
        "anchor": "'t Hooft loops and perturbation theory: We show that high-temperature perturbation theory describes extremely well\nthe area law of SU(N) spatial 't Hooft loops, or equivalently the tension of\nthe interface between different Z_N vacua in the deconfined phase. For SU(2),\nthe disagreement between Monte Carlo data and lattice perturbation theory for\nsigma(T)/T^2 is less than 2%, down to temperatures O(10) T_c. For SU(N), N>3,\nthe ratios of interface tensions, (sigma_k/sigma_1)(T), agree with perturbation\ntheory, which predicts tiny deviations from the ratio of Casimirs, down to\nnearly T_c. In contrast, individual tensions differ markedly from the\nperturbative expression. In all cases, the required precision Monte Carlo\nmeasurements are made possible by a simple but powerful modification of the\n'snake' algorithm.",
        "positive": "Nucleon Structure with Domain Wall Fermions at a = 0.084 fm: We present initial calculations of nucleon matrix elements of twist-two\noperators with 2+1 flavors of domain wall fermions at a lattice spacing a =\n0.084 fm for pion masses down to 300 MeV. We also compare the results with the\ndomain wall calculations on a coarser lattice."
    },
    {
        "anchor": "Exact $\u03b2$-function of Yang-Mills theory in 2+1 dimensions: To set the stage, I discuss the $\\beta$-function of the massless O(N) model\nin three dimensions, which can be calculated exactly in the large N limit.\nThen, I consider SU(N) Yang-Mills theory in 2+1 space-time dimensions. Relating\nthe $\\beta$-function to the expectation value of the action in lattice gauge\ntheory, and the latter to the trace of the energy-momentum tensor, I show that\n$\\frac{d \\ln g^2/\\mu}{d\\ln \\mu}=-1$ for all $g$ and all N in one particular\nrenormalization scheme. As a consequence, I find that the Yang-Mills\n$\\beta$-function in three dimensions must have the same sign for all finite and\npositive bare coupling parameters in any renormalization scheme, and all\nnon-trivial infrared fixed points are unreachable in practice.",
        "positive": "Examples of symmetry-preserving truncations in tensor field theory: We consider the tensor formulation of the non-linear O(2) sigma model and its\ngauged version (the compact Abelian Higgs model), on a $D$-dimensional cubic\nlattice, and show that tensorial truncations are compatible with the general\nidentities derived from the symmetries of these models. This means that the\nuniversal properties of these models can be reproduced with highly simplified\nformulations desirable for implementations with quantum computers or for\nquantum simulations experiments. We briefly discuss the extensions to\nnon-Abelian symmetries and models with fermions."
    },
    {
        "anchor": "Phase structure of $N_{\\rm f}=3$ QCD at finite temperature and density\n  by Wilson-Clover fermions: We investigate the phase structure of 3-flavor QCD in the presence of finite\nquark chemical potential by using Wilson-Clover fermions. To deal with the\ncomplex action with finite density, we adopt the phase reweighting method. In\norder to survey a wide parameter region, we employ the multi-parameter\nreweighting method as well as the multi-ensemble reweighting method.\nEspecially, we focus on locating the critical end point that characterizes the\nphase structure. It is estimated by the kurtosis intersection method for the\nquark condensate. For Wilson-type fermions, the correspondence between bare\nparameters and physical parameters is indirect, thus we present a strategy to\ntransfer the bare parameter phase structure to the physical one. We conclude\nthat the curvature with respect to the chemical potential is positive. This\nimplies that, if one starts from a quark mass in the region of crossover at\nzero chemical potential, one would encounter a first-order phase transition\nwhen one raises the chemical potential.",
        "positive": "Non-Perturbative Renormalisation and Running of BSM Four-Quark Operators\n  in $N_f = 2$ QCD: We perform a non-perturbative study of the scale-dependent renormalisation\nfactors of a complete set of dimension-six four-fermion operators. The\nrenormalisation-group (RG) running is determined in the continuum limit for a\nspecific Schr\\\"dinger Functional (SF) renormalisation scheme in the framework\nof lattice QCD with two dynamical flavours ( $N_f = 2$ ). The theory is\nregularised on a lattice with a plaquette Wilson action and\n$\\mathcal{O}(a)$-improved Wilson fermions. For one of these operators, the\ncomputation had been performed in ref. [1]; the present work completes the\nstudy for the rest of the operator basis, on the same simulations\n(configuration ensembles). The related weak matrix elements arise in several\noperator product expansions; in $\\Delta F = 2$ transitions they contain the QCD\nlong-distance effects, including contributions from beyond-Standard Model (BSM)\nprocesses. Some of these operators mix under renormalisation and their\nRG-running is governed by anomalous dimension matrices. In ref. [2] the RG\nformalism for the operator basis has been worked out in full generality and the\nanomalous dimension matrix has been calculated in NLO perturbation theory. Here\nthe discussion is extended to the matrix step-scaling functions (matrix-SSFs),\nwhich are used in finite-size recursive techniques. We rely on these\nmatrix-SSFs to obtain non-perturbative estimates of the operator anomalous\ndimensions for scales ranging from $\\mathcal{O}(\\Lambda_{\\rm QCD})$ to\n$\\mathcal{O}(M_W)$."
    },
    {
        "anchor": "Glueball masses from ratios of path integrals: By generalizing our previous work on the parity symmetry, the partition\nfunction of a Yang-Mills theory is decomposed into a sum of path integrals each\ngiving the contribution from multiplets of states with fixed quantum numbers\nassociated to parity, charge conjugation, translations, rotations and central\nconjugations. Ratios of path integrals and correlation functions can then be\ncomputed with a multi-level Monte Carlo integration scheme whose numerical\ncost, at a fixed statistical precision and at asymptotically large times,\nincreases power-like with the time extent of the lattice. The strategy is\nimplemented for the SU(3) Yang-Mills theory, and a full-fledged computation of\nthe mass and multiplicity of the lightest glueball with vacuum quantum numbers\nis carried out at two values of the lattice spacing (0.17 and 0.12 fm).",
        "positive": "The Schroedinger functional for Gross-Neveu models: Gross-Neveu type models with a finite number of fermion flavours are studied\non a two-dimensional Euclidean space-time lattice. The models are\nasymptotically free and are invariant under a chiral symmetry. These\nsimilarities to QCD make them perfect benchmark systems for fermion actions\nused in large scale lattice QCD computations. The Schroedinger functional for\nthe Gross-Neveu models is defined for both, Wilson and Ginsparg-Wilson\nfermions, and shown to be renormalisable in 1-loop lattice perturbation theory.\nIn two dimensions four fermion interactions of the Gross-Neveu models have\ndimensionless coupling constants. The symmetry properties of the four fermion\ninteraction terms and the relations among them are discussed. For Wilson\nfermions chiral symmetry is explicitly broken and additional terms must be\nincluded in the action. Chiral symmetry is restored up to cut-off effects by\ntuning the bare mass and one of the couplings. The critical mass and the\nsymmetry restoring coupling are computed to second order in lattice\nperturbation theory. This result is used in the 1-loop computation of the\nrenormalised couplings and the associated beta-functions. The renormalised\ncouplings are defined in terms of suitable boundary-to-boundary correlation\nfunctions. In the computation the known first order coefficients of the\nbeta-functions are reproduced. One of the couplings is found to have a\nvanishing beta-function. The calculation is repeated for the recently proposed\nSchroedinger functional with exact chiral symmetry, i.e. Ginsparg-Wilson\nfermions. The renormalisation pattern is found to be the same as in the Wilson\ncase. Using the regularisation dependent finite part of the renormalised\ncouplings, the ratio of the Lambda-parameters is computed."
    },
    {
        "anchor": "Scaling functions for O(4) in three dimensions: Monte Carlo simulation using a cluster algorithm is used to compute the\nscaling part of the free energy for a three dimensional O(4) spin model. The\nresults are relevant for analysis of lattice studies of high temperature QCD.",
        "positive": "Machine learning a fixed point action for SU(3) gauge theory with a\n  gauge equivariant convolutional neural network: Fixed point lattice actions are designed to have continuum classical\nproperties unaffected by discretization effects and reduced lattice artifacts\nat the quantum level. They provide a possible way to extract continuum physics\nwith coarser lattices, thereby allowing to circumvent problems with critical\nslowing down and topological freezing toward the continuum limit. A crucial\ningredient for practical applications is to find an accurate and compact\nparametrization of a fixed point action, since many of its properties are only\nimplicitly defined. Here we use machine learning methods to revisit the\nquestion of how to parametrize fixed point actions. In particular, we obtain a\nfixed point action for four-dimensional SU(3) gauge theory using convolutional\nneural networks with exact gauge invariance. The large operator space allows us\nto find superior parametrizations compared to previous studies, a necessary\nfirst step for future Monte Carlo simulations."
    },
    {
        "anchor": "Renormalization factors of quark bilinears using the DCI operator with\n  dynamical quarks: Non-perturbative renormalization factors of bilinear quark operators are\ncomputed for the Chirally Improved lattice action with two dynamic quarks. The\nanalysis is based on five different parameter sets with lattice size 12^3 x 24\nand four parameter sets with lattice size 16^3 x 32. For the pseudoscalar\nrenormalization factor the pion pole contribution is subtracted and chiral\nextrapolations are performed. Results are given in RIprime- and MSbar-scheme as\nwell as in RGI-form.",
        "positive": "Chiral Perturbation Theory for the Quenched Approximation of QCD: [This version is a minor revision of a previously submitted preprint. Only\nreferences have been changed.] We describe a technique for constructing the\neffective chiral theory for quenched QCD. The effective theory which results is\na lagrangian one, with a graded symmetry group which mixes Goldstone bosons and\nfermions, and with a definite (though slightly peculiar) set of Feynman rules.\nThe straightforward application of these rules gives automatic cancellation of\ndiagrams which would arise from virtual quark loops. The techniques are used to\ncalculate chiral logarithms in $f_K/f_\\pi$, $m_\\pi$, $m_K$, and the ratio of\n$\\langle{\\bar s}s\\rangle$ to $\\langle{\\bar u}u\\rangle$. The leading\nfinite-volume corrections to these quantities are also computed. Problems for\nfuture study are described."
    },
    {
        "anchor": "QCD material parameters at zero and non-zero chemical potential from the\n  lattice: Using an eighth-order Taylor expansion in baryon chemical potential, we\nrecently obtained the (2+1)-flavor QCD equation of state (EoS) at non-zero\nconserved charge chemical potentials from the lattice. We focused on\nstrangeness-neutral, isospin-symmetric QCD matter, which closely resembles the\nsituation encountered in heavy-ion collision experiments. Using this EoS, we\npresent here results on various QCD material parameters; in particular we\ncompute the specific heat, speed of sound, and compressibility along\nappropriate lines of constant physics. We show that in the entire range\nrelevant for the beam energy scan at RHIC, the specific heat, speed of sound,\nand compressibility show no indication for an approach to critical behavior\nthat one would expect close to a possibly existing critical endpoint.",
        "positive": "Short comment about the lattice gluon propagator at vanishing momentum: We argue that all evidences point towards a finite non-vanishing zero\nmomentum renormalised lattice gluon propagator in the infinite volume limit. We\nargue that different simulations with different lattice setups end-up with\nfairly compatible results for the gluon propagator at zero momentum, with\ndifferent positive slopes as a function of the inverse volume."
    },
    {
        "anchor": "Calorons and BPS monopoles with non-trivial holonomy in the confinement\n  phase of SU(2) gluodynamics: With the help of the cooling method applied to SU(2) lattice gauge theory at\nnon-zero $T \\le T_c$ we present numerical evidence for the existence of\nsuperpositions of Kraan-van Baal caloron (or BPS monopole pair) solutions with\nnon-trivial holonomy, which might constitute an important contribution to the\nsemi-classical approximation of the partition function.",
        "positive": "Bound H-dibaryon in the Flavor SU(3) Limit from a Full QCD Simulation on\n  the Lattice: Existence of the H-dibaryon in the flavor SU(3) symmetric limit is studied by\nfull QCD simulations on the lattice, in the approach recently developed for the\nbaryon-baryon (BB) interactions. Potential of the flavor-singlet BB channel is\nderived from the Nambu-Bethe-Salpeter wave function, and a bound H-dibaryon is\ndiscovered from it, with the binding energy of 20--50 MeV for the pseudo-scalar\nmeson mass of 469--1171 MeV."
    },
    {
        "anchor": "Parallel software for lattice N=4 supersymmetric Yang--Mills theory: We present new parallel software, SUSY LATTICE, for lattice studies of\nfour-dimensional $\\mathcal N = 4$ supersymmetric Yang--Mills theory with gauge\ngroup SU(N). The lattice action is constructed to exactly preserve a single\nsupersymmetry charge at non-zero lattice spacing, up to additional potential\nterms included to stabilize numerical simulations. The software evolved from\nthe MILC code for lattice QCD, and retains a similar large-scale framework\ndespite the different target theory. Many routines are adapted from an existing\nserial code, which SUSY LATTICE supersedes. This paper provides an overview of\nthe new parallel software, summarizing the lattice system, describing the\napplications that are currently provided and explaining their basic workflow\nfor non-experts in lattice gauge theory. We discuss the parallel performance of\nthe code, and highlight some notable aspects of the documentation for those\ninterested in contributing to its future development.",
        "positive": "Dynamical Twisted Mass Fermions with Light Quarks: Simulation and\n  Analysis Details: In a recent paper [hep-lat/0701012] we presented precise lattice QCD results\nof our European Twisted Mass Collaboration (ETMC). They were obtained by\nemploying two mass-degenerate flavours of twisted mass fermions at maximal\ntwist. In the present paper we give details on our simulations and the\ncomputation of physical observables. In particular, we discuss the problem of\ntuning to maximal twist, the techniques we have used to compute correlators and\nerror estimates. In addition, we provide more information on the algorithm\nused, the autocorrelation times and scale determination, the evaluation of\ndisconnected contributions and the description of our data by means of chiral\nperturbation theory formulae."
    },
    {
        "anchor": "Low-lying baryon masses using twisted mass fermions ensembles at the\n  physical pion mass: We investigate the low-lying baryon spectrum using three $N_f$=2+1+1\nensembles simulated with physical values of the quark masses and lattice\nspacings of 0.080, 0.069, and 0.057 fm. The ensembles are generated using\ntwisted mass clover-improved fermions and the Iwasaki gauge action. The spatial\nlength is kept approximately the same at about 5.1 fm to 5.5 fm fulfilling the\ncondition $m_\\pi L$> 3.6. We investigate isospin splitting within isospin\nmultiples and verify that for most cases the isospin splitting for these\nlattice spacing is consistent with zero. In the couple of cases, for which\nthere is a non-zero value, in the continuum limit, the mass splitting goes to\nzero. The baryon masses are extrapolated to the continuum limit using the three\n$N_f$=2+1+1 ensembles and are compared to other recent lattice QCD results. For\nthe strange and charm quark masses, we find, respectively, $m_s$(2\nGeV)=99.2(2.7) MeV and $m_c$(3 GeV)=1.015(39) GeV. The values predicted for the\nmasses of the doubly charmed $\\Xi_{cc}^\\star$, $\\Omega_{cc}$ and\n$\\Omega_{cc}^\\star$ baryons are 3.676(55) GeV, 3.703(51) GeV and 3.803(50) GeV,\nrespectively, and for the triply charmed $\\Omega_{ccc}$ baryon is 4.785(71)\nGeV.",
        "positive": "Topological gauge actions on the lattice as Overlap fermion determinants: Overlap fermion on the lattice has been shown to properly reproduce\ntopological aspects of gauge fields. In this paper, we review the derivation of\nOverlap fermion formalism in a torus of three space-time dimensions. Using the\nformalism, we show how to use the Overlap fermion determinants in the massless\nand infinite mass limits to construct different continuum topological gauge\nactions, such as the level-$k$ Chern-Simons action, ``half-CS\" term and the\nmixed Chern-Simons (BF) coupling, in a gauge-invariant lattice UV regulated\nmanner. Taking special Abelian and non-Abelian background fields, we\ndemonstrate numerically how the lattice formalism beautifully reproduces the\ncontinuum expectations, such as the flow of action under large gauge\ntransformations."
    },
    {
        "anchor": "Probing the QCD Vacuum with Static Sources in Maximal Abelian Projection: Various field strength correlators are investigated in the maximal Abelian\nprojection of pure SU(2) lattice gauge theory. High precision measurements of\nthe colour fields, monopole currents, their curls and divergences allow for\ndetailed checks of the dual superconductor scenario. On this basis, we perform\na Ginzburg-Landau type analysis of the flux tube profile from which we derive\nthe size of the penetration length, LAMBDA = 0.16(2) fm, and coherence length\nof the monopole condensate wave function, XI = 0.27(3) fm. The ratio of these\nnumbers is KAPPA = LAMBDA/XI = 0.59(13) which is below the value 1/SQRT(2)\nwhere type II superconductivity sets in.",
        "positive": "Twisted mass lattice QCD: Recent developments and results: I review recent theoretical developments and numerical results of twisted\nmass QCD. I argue that, combined with an efficient algorithm, twisted mass QCD\ncan be an attractive QCD lattice action, to perform large scale simulations at\nsmall pion masses, where a matching with chiral perturbation theory can be\nperformed. Open issues like flavour breaking effects are also addressed."
    },
    {
        "anchor": "Scaling Study of Pure Gauge Lattice QCD by Monte Carlo Renormalization\n  Group Method: The scaling behavior of pure gauge SU(3) in the region $\\beta=5.85 - 7.60$ is\nexamined by a Monte Carlo Renormalization Group analysis. The coupling shifts\ninduced by factor 2 blocking are measured both on 32$^4$ and 16$^4$ lattices\nwith high statistics. A systematic deviation from naive 2-loop scaling is\nclearly seen. The mean field and effective coupling constant schemes explain\npart, but not all of the deviation. It can be accounted for by a suitable\nchange of coupling constant, including a correction term ${\\cal O}(g^7)$ in the\n2-loop lattice $\\beta$-function. Based on this improvement,\n$\\sqrt{\\sigma}/\\Lambda_{\\overline {MS}}^{n_f=0}$ is estimated to be $2.2(\\pm\n0.1)$ from the analysis of the string tension $\\sigma$.",
        "positive": "CP(N-1) Models with Theta Term and Fixed Point Action: The topological charge distribution P(Q) is calculated for lattice ${\\rm\nCP}^{N-1}$ models. In order to suppress lattice cut-off effects we employ a\nfixed point (FP) action. Through transformation of P(Q) we calculate the free\nenergy $F(\\theta)$ as a function of the $\\theta$ parameter. For N=4, scaling\nbehavior is observed for P(Q), $F(\\theta)$ as well as the correlation lengths\n$\\xi(Q)$. For N=2, however, scaling behavior is not observed as expected. For\ncomparison, we also make a calculation for the ${\\rm CP}^{3}$ model with\nstandard action. We furthermore pay special attention to the behavior of P(Q)\nin order to investigate the dynamics of instantons. For that purpose, we\ncarefully look at behavior of $\\gamma_{\\it eff}$, which is an effective power\nof P(Q)($\\sim \\exp(-CQ^{\\gamma_{\\it eff}})$), and reflects the local behavior\nof P(Q) as a function of Q. We study $\\gamma_{\\it eff}$ for two cases, one of\nwhich is the dilute gas approximation based on the Poisson distribution of\ninstantons and the other is the Debye-H\\\"uckel approximation of instanton\nquarks. In both cases we find similar behavior to the one observed in numerical\nsimulations."
    },
    {
        "anchor": "Hopping Parameter Series Construction for Models with Nontrivial Vacuum: Hopping parameter expansions are convergent power series. Under general\nconditions they allow for the quantitative investigation of phase transition\nand critical behaviour. The critical information is encoded in the high order\ncoefficients. Recently, 20th order computations have become feasible and used\nfor a large class of lattice field models both in finite and infinite volume.\nThey have been applied to quantum spin models and field theories at finite\ntemperature. The models considered are subject to a global ${\\bf Z}_2$ symmetry\nor to an even larger symmetry group such as O(N) with $N\\geq 2$. In this paper\nwe are concerned with the technical details of series computations to allow for\na nontrivial vacuum expectation value $<\\rho(x)>\\not=0$, which is typical for\nmodels that break a global ${\\bf Z}_2$ symmetry. Examples are scalar fields\ncoupled to an external field, or manifestly gauge invariant effective models of\nHiggs field condensates in the electroweak theory, even in the high temperature\nphase. A nonvanishing tadpole implies an enormous proliferation of graphs and\nlimits the graphical series computation to the 10th order. To achieve the\nhopping parameter series to comparable order as in the ${\\bf Z}_2$ symmetric\ncase, the graphical expansion is replaced by an expansion into new algebraic\nobjects called vertex structures. In this way the 18th order becomes feasible.",
        "positive": "Long and short distance behavior of the imaginary part of the\n  heavy-quark potential: The imaginary part of the effective heavy-quark potential is related to the\ntotal in-medium decay width of heavy quark-antiquark bound states. We extract\nthe static limit of this quantity using classical-statistical simulations of\nreal-time Yang-Mills dynamics by measuring the temporal decay of Wilson loops.\nBy performing the simulations on finer and larger lattices, we are able to show\nthat the nonperturbative results follow the same form as the perturbative ones.\nFor large quark-antiquark separations, we quantify the magnitude of the\nnon-perturbative long-range corrections to the imaginary part of the\nheavy-quark potential. We present our results for a wide range of temperatures,\nlattice spacings, and lattice volumes. We also extract approximations for the\nshort-distance behavior of the classical potential."
    },
    {
        "anchor": "Monte Carlo Simulations of Conformal Theory Predictions for the 3-state\n  Potts and Ising Models: The critical properties of the 2D Ising and 3-state Potts models are\ninvestigated using Monte Carlo simulations. Special interest is given to\nmeasurement of 3-point correlation functions and associated universal objects,\ni.e. structure constants. The results agree well with predictions coming from\nconformal field theory confirming, for these examples, the correctness of the\nCoulomb gas formalism and the bootstrap method.",
        "positive": "Large N meson propagators from twisted space-time reduced model: Recently, we proposed a new method to calculate meson propagators in the\nlarge $N$ limit from twisted space-time reduced model. In this note, we give\nsimulation details for obtaining meson spectra and discuss the smearing\ntechnique which should improve the signal of meson propagators in future works."
    },
    {
        "anchor": "On $SU(2)_{CS}$-like groups and invariance of the fermionic action in\n  QCD: In this work, we introduce some new $U(1)$ symmetry groups of the free\nfermionic action in euclidean space-time, which are a consequence of parity and\ntime-reversal symmetries. Afterwards, we discuss how the introduction of a\ngauge interaction affects the invariance of the action, with special reference\nto QCD. Moreover, inspired by recent QCD lattice results of \\textit{Glozman et\nal.}, in which an interesting and unexpected symmetry group has been observed,\nnamely $SU(2)_{CS}$ (that contains $U(1)_A$ as subgroup), we build other\n$SU(2)_{CS}$-like groups in euclidean space-time using the previous introduced\n$U(1)$ groups. Finally we argue about the possible invariance of the fermionic\naction with respect these new $SU(2)_{CS}$-like groups and its consequence on\nthe hadron temporal correlators.",
        "positive": "String tension from smearing and Wilson flow methods: Recently, we proposed a new method to extract the string tension from\n4-dimensionally smeared Wilson loops. In this talk, we first show that the\nresults obtained using this smearing method are identical to those obtained by\nWilson flow, once the time step is sufficiently small. We then demonstrate the\npractical advantage of our method by applying it to the calculation of string\ntension in SU(3) Yang-Mills theory."
    },
    {
        "anchor": "Adjoint zero-modes as a tool to understand the Yang-Mills vacuum: The use of adjoint (quasi) zero-modes of the Dirac operator to probe the\nYangs-Mills vacuum has been recently advocated by Gonzalez-Arroyo and Kirchner.\nThe construction relies on the use of the super-symmetric zero mode which, for\nclassical configurations, provides a direct estimate of the gauge action\ndensity. In the lattice implementation of this idea, we show how the results\nimprove considerably if the overlap operator is used instead of the\nWilson-Dirac one. Before proceeding to the detailed study of Monte Carlo\nensembles, we studied here a series of potentially complicated situations which\ncan be encountered. In particular, we study the case of instanton\nanti-instanton pairs and analyse how the results depend upon separation. The\neffect of lattice artifacts is also of concern. Indeed, a statistical analysis\nof zero modes of thermalised SU(2) configurations at beta=2.57 shows a\nsignificant fraction having 4N+2 adjoint zero modes, in contradiction with the\nindex theorem. This violation must be associated to the roughness of the\nlattice configurations. Indeed, we show that this situation occurs for\ninstantons of size of the order of the lattice spacing.",
        "positive": "The Phase Diagram of Three-Dimensional SU(3) + Adjoint Higgs Theory: We study the phase diagram of the three-dimensional SU(3)+adjoint Higgs\ntheory with lattice Monte Carlo simulations. A critical line consisting of a\nfirst order line, a tricritical point and a second order line, divides the\nphase diagram into two parts distinguished by <Tr A0^3>=0 and /=0. The location\nand the type of the critical line are determined by measuring the condensates\n<Tr A0^2> and <Tr A0^3>, and the masses of scalar and vector excitations.\nAlthough in principle there can be different types of broken phases,\ncorresponding perturbatively to unbroken SU(2)xU(1) or U(1)xU(1) symmetries, we\nfind that dynamically only the broken phase with SU(2)xU(1)-like properties is\nrealized. The relation of the phase diagram to 4d finite temperature QCD is\ndiscussed."
    },
    {
        "anchor": "Random Matrix Theory and Chiral Logarithms: Recently, the contributions of chiral logarithms predicted by quenched chiral\nperturbation theory have been extracted from lattice calculations of hadron\nmasses. We argue that a detailed comparison of random matrix theory and lattice\ncalculations allows for a precise determination of such corrections. We\nestimate the relative size of the m*log(m), m, and m^2 corrections to the\nchiral condensate for quenched SU(2).",
        "positive": "Structure functions from the Compton amplitude: We have initiated a program to compute the Compton amplitude from lattice QCD\nwith the Feynman-Hellman method. This amplitude is related to the structure\nfunction via a Fredholm integral equation of the first kind. It is known that\nthese types of equations are inherently ill--posed - they are, e.g., extremely\nsensitive to perturbations of the system. We discuss two methods which are\ncandidates to handle these problems: the model free inversion based on singular\nvalue decomposition and one Bayesian type approach. We apply the Bayesian\nmethod to currently available lattice data for the Compton amplitude."
    },
    {
        "anchor": "A Novel Ansatz for the Energy-Momentum Tensor on the Lattice: The comparison of structural analogies between the energy-momentum tensors in\ngeneral relativity and in a gauge theory of Yang-Mills type is tentatively\nextended to lattice physics. These considerations are guiding to a new lattice\nmodel for the symmetric energy-momentum tensor $\\Theta_{\\mu\\nu}$ of the pure\nYang-Mills gauge sector, basing on half powers of the plaquette variable. The\nconcept of non-trivial principal square roots of unitary matrices in lattice\ngauge theories can be epitomized to reconcile the pretension to a uniform\nconstruction principle for the components of $\\Theta_{\\mu\\nu}$ with general\nqualitative thermodynamic demands concerning arguments in favour of a Wilson\nform for $<\\Theta^\\mu_\\mu>$ and $\\Theta_{44}$. SU(2) Monte Carlo results for\nthe Euclidean expectation values on a 10**4 lattice are compared with that of\ncompeting hitherto existing lattice models for $\\Theta_{\\mu\\nu}$.",
        "positive": "Vortex liquid in magnetic-field-induced superconducting vacuum of\n  quenched lattice QCD: In the background of the strong magnetic field the vacuum is suggested to\npossess an electromagnetically superconducting phase characterised by the\nemergence of inhomogeneous quark-antiquark vector condensates which carry\nquantum numbers of the charged rho mesons. The rho-meson condensates are\ninhomogeneous due to the presence of the stringlike defects (\"the rho\nvortices\") which are parallel to the magnetic field (the superconducting vacuum\nphase is similar to the mixed Abrikosov phase of a type-II superconductor). In\nagreement with these expectations, we have observed the presence of the rho\nvortices in numerical simulations of the vacuum of the quenched two-color\nlattice QCD in strong magnetic field background. We have found that in the\nquenched QCD the rho vortices form a liquid. The transition between the usual\n(insulator) phase at low B and the superconducting vortex liquid phase at high\nB turns out to be very smooth, at least in the quenched QCD."
    },
    {
        "anchor": "The quenched generating functional for hadronic weak interactions: The ultraviolet behaviour of the generating functional for hadronic weak\ninteractions with $|\\Delta S| =1, 2$ is investigated to one loop for a generic\nnumber of flavours and in the quenched approximation. New quenched chiral\nlogarithms generated by the weak interactions can be accounted for via a\nredefinition of the weak mass term in the $\\Delta S=\\pm 1$ weak effective\nLagrangian at leading order. Finally, we illustrate how chiral logarithms are\nmodified by the quenched approximation in $K\\to\\pi\\pi$ matrix elements with\n$\\Delta I=1/2$ and 3/2.",
        "positive": "The Bulk Channel in Thermal Gauge Theories: We investigate the thermal correlator of the trace of the energy-momentum\ntensor in the SU(3) Yang-Mills theory. Our goal is to constrain the spectral\nfunction in that channel, whose low-frequency part determines the bulk\nviscosity. We focus on the thermal modification of the spectral function,\n$\\rho(\\omega,T)-\\rho(\\omega,0)$. Using the operator-product expansion we give\nthe high-frequency behavior of this difference in terms of thermodynamic\npotentials. We take into account the presence of an exact delta function\nlocated at the origin, which had been missed in previous analyses. We then\ncombine the bulk sum rule and a Monte-Carlo evaluation of the Euclidean\ncorrelator to determine the intervals of frequency where the spectral density\nis enhanced or depleted by thermal effects. We find evidence that the thermal\nspectral density is non-zero for frequencies below the scalar glueball mass $m$\nand is significantly depleted for $m\\lesssim\\omega\\lesssim 3m$."
    },
    {
        "anchor": "The pi-N Sigma term - an evaluation using staggered fermions: A lattice calculation of the pi-N sigma term is described using dynamical\nstaggered fermions. Preliminary results give a sea term comparable in magnitude\nto the valence term.",
        "positive": "Renormalization of the Classical Velocity in the Lattice Heavy Quark\n  Effective Theory: In the lattice formulation of the Heavy Quark Effective Theory (LHQET), the\nclassical velocity becomes renormalized. The origin of this renormalization is\nthe reduction of Lorentz (or O(4)) invariance to (hyper)cubic invariance. The\nrenormalization is finite, depends on the form of the discretization of the\nreduced heavy quark Dirac equation, and can persist down to zero lattice\nspacing. For the Forward Time - Centered Space discretization, the\nrenormalization is computed both perturbatively, to one loop, and\nnon-perturbatively using an ensemble of lattices provided by the Fermilab\nACP-MAPS collaboration. The estimates of the leading multiplicative shift agree\nreasonably well, and indicate that to first order, the classical velocity is\nreduced by about 20-25%."
    },
    {
        "anchor": "Automated generation of lattice QCD Feynman rules: The derivation of the Feynman rules for lattice perturbation theory from\nactions and operators is complicated, especially for highly improved actions\nsuch as HISQ. This task is, however, both important and particularly suitable\nfor automation. We describe a suite of software to generate and evaluate\nFeynman rules for a wide range of lattice field theories with gluons and\n(relativistic and/or heavy) quarks. Our programs are capable of dealing with\nactions as complicated as (m)NRQCD and HISQ. Automated differentiation methods\nare used to calculate also the derivatives of Feynman diagrams.",
        "positive": "Performance studies of the two-step multiboson algorithm in compact\n  lattice QED: The performance of the two-step multiboson (TSMB) algorithm is investigated\nin comparison with the hybrid Monte Carlo (HMC) method for compact lattice QED\nwith standard Wilson fermions both in the Coulomb and confinement phases. The\nrestriction to QED allows for extensive measurements of autocorrelation times.\nPreliminary results show that the TSMB algorithm is at least competitive with\nstandard HMC."
    },
    {
        "anchor": "NSPT estimate of the improvement coefficient $c_A$ to two loops: By using Numerical Stochastic Perturbation Theory (NSPT), we carry out a\nquenched two-loop computation of the improvement coefficient $c_A$ associated\nto the isovector axial current. Within the Schr\\\"odinger Functional formalism,\nwe compute the bare quark mass $m$ and fix $c_A$ by requiring discretization\ncorrections on $m$ to be of order $O(a^2)$ in the lattice spacing $a$.",
        "positive": "Non--perturbative bounds on the Higgs mass in the minimal standard model: This is a slightly extended version of the talk delivered at the Topical\nWorkshop ``Non perturbative aspects of chiral gauge theories'', Accademia\nNazionale dei Lincei, Roma, 9-11 March, 1992. Abstract: The Higgs mass in the\nminimal standard model is bounded by triviality and vacuum stability in the\nrange 50--100 $GeV$ to 700--900 $GeV$. Recent results will be presented in\nbrief and directions for future work will be proposed."
    },
    {
        "anchor": "Improved topological sampling for lattice gauge theories: Standard sampling algorithms for lattice QCD suffer from topology freezing\n(or critical slowing down) when approaching the continuum limit, thus leading\nto poor sampling of the distinct topological sectors. I will present a modified\nHamiltonian Monte Carlo (HMC) algorithm that triggers topological sector jumps\nduring the assembly of Markov chain of lattice configurations. We study its\nperformance in the 2D Schwinger model and compare it to alternative methods,\nsuch as fixing topology or master field. We then briefly discuss the\ndifficulties of the algorithm in a SU(2) gauge model in 4D.",
        "positive": "Monopoles and Chaos: We decompose U(1) gauge fields into a monopole and photon part across the\nphase transition from the confinement to the Coulomb phase. We analyze the\nleading Lyapunov exponents of such gauge field configurations on the lattice\nwhich are initialized by quantum Monte Carlo simulations. It turns out that\nthere is a strong relation between the sizes of the monopole density and the\nLyapunov exponent."
    },
    {
        "anchor": "Hadronic susceptibilities for b to c transitions from two point\n  correlation functions: We present a lattice determination of the hadronic susceptibilities that,\nthanks to unitarity and analyticity, constrain the form factors entering the\nsemileptonic $b\\rightarrow c$ transitions. We evaluate the transverse and\nlongitudinal susceptibilities of the vector and axial polarization functions at\nzero momentum transfer from the moments of appropriate two-point correlation\nfunctions. The latter are obtained on the lattice employing gauge ensembles of\nthe Extended Twisted Mass Collaboration (ETMC) with $N_f$=2+1+1 flavors of\nWilson-clover twisted-mass quarks with masses of all the dynamical quark\nflavors tuned close to their physical values. The simulations are carried out\nat four values of the lattice spacing, $a \\simeq (0.057,0.068, 0.080, 0.091)$\nfm, with spatial lattice sizes up to $L \\simeq 7.6$ fm. Heavy-quark masses up\nto $\\approx 3.5$ times the physical charm mass are employed, allowing for a\nsmooth extrapolation to the physical b-quark mass.",
        "positive": "Are two nucleons bound in lattice QCD for heavy quark masses? --\n  Consistency check with L\u00fcscher's finite volume formula --: On the basis of the L\\\"uscher's finite volume formula, a simple test\n(consistency check or sanity check) is introduced and applied to inspect the\nrecent claims of the existence of the nucleon-nucleon ($NN$) bound state(s) for\nheavy quark masses in lattice QCD. We show that the consistency between the\nscattering phase shifts at $k^2 > 0$ and/or $k^2 < 0$ obtained from the lattice\ndata and the behavior of phase shifts from the effective range expansion (ERE)\naround $k^2=0$ exposes the validity of the original lattice data, otherwise\nsuch information is hidden in the energy shift $\\Delta E$ of the two nucleons\non the lattice. We carry out this sanity check for all the lattice results in\nthe literature claiming the existence of the $NN$ bound state(s) for heavy\nquark masses, and find that (i) some of the $NN$ data show clear inconsistency\nbetween the behavior of ERE at $k^2 > 0$ and that at $k^2 < 0$, (ii) some of\nthe $NN$ data exhibit singular behavior of the low energy parameter (such as\nthe divergent effective range) at $k^2<0$, (iii) some of the $NN$ data have the\nunphysical residue for the bound state pole in S-matrix, and (iv) the rest of\nthe $NN$ data are inconsistent among themselves. Furthermore, we raise a\ncaution of using the ERE in the case of the multiple bound states. Our finding,\ntogether with the fake plateau problem previously pointed out by the present\nauthors, brings a serious doubt on the existence of the $NN$ bound states for\npion masses heavier than 300 MeV in the previous studies."
    },
    {
        "anchor": "Chiral Symmetry Breaking and Chiral Polarization: Tests for Finite\n  Temperature and Many Flavors: It was recently conjectured that, in SU(3) gauge theories with fundamental\nquarks, valence spontaneous chiral symmetry breaking is equivalent to\ncondensation of local dynamical chirality and appearance of chiral polarization\nscale $\\Lambda_{ch}$. Here we consider more general association involving the\nlow-energy layer of chirally polarized modes which, in addition to its width\n($\\Lambda_{ch}$), is also characterized by volume density of participating\nmodes ($\\Omega$) and the volume density of total chirality ($\\Omega_{ch}$). Few\npossible forms of the correspondence are discussed, paying particular attention\nto singular cases where $\\Omega$ emerges as the most versatile characteristic.\nThe notion of finite-volume \"order parameter\", capturing the nature of these\nconnections, is proposed. We study the effects of temperature (in N$_f$=0 QCD)\nand light quarks (in N$_f$=12), both in the regime of possible symmetry\nrestoration, and find agreement with these ideas. In N$_f$=0 QCD, results from\nseveral volumes indicate that, at the lattice cutoff studied, the deconfinement\ntemperature $T_c$ is strictly smaller than the overlap-valence chiral\ntransition temperature $T_{ch}$ in real Polyakov line vacuum. Somewhat similar\nintermediate phase (in quark mass) is also seen in N$_f$=12. It is suggested\nthat deconfinement in N$_f$=0 is related to indefinite convexity of absolute\nX-distributions.",
        "positive": "Computers for Lattice Field Theories: Parallel computers dedicated to lattice field theories are reviewed with\nemphasis on the three recent projects, the Teraflops project in the US, the\nCP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new\ncommercial parallel computers are also discussed. Recent development of\nsemiconductor technologies is briefly surveyed in relation to possible\napproaches toward Teraflops computers."
    },
    {
        "anchor": "Estimating $\u03c7_\\mathrm{top}$ Lattice Artifacts from Flowed SU(2)\n  Calorons: Lattice computations of the high-temperature topological susceptibility of\nQCD receive lattice-spacing corrections and suffer from systematics arising\nfrom the type and depth of gradient flow. We study the lattice spacing\ncorrections to $\\chi_\\mathrm{top}$ semi-analytically by exploring the behavior\nof discretized Harrington-Shepard calorons under the action of different forms\nof gradient flow. From our study we conclude that $N_\\tau = 6$ is definitely\ntoo small of a time extent to study the theory at temperatures of order\n$4~T_\\mathrm{c}$ and we explore how the amount of gradient flow influences the\ncontinuum extrapolation.",
        "positive": "Double poles in Lattice QCD with mixed actions: We consider effects resulting from the use of different discretizations for\nthe valence and the sea quarks, considering Wilson and/or Ginsparg--Wilson\nfermions. We assume that such effects appear through scaling violations that\ncan be studied using effective-lagrangian techniques. We show that a double\npole is present in flavor-neutral Goldstone meson propagators, even if the\nflavor non-diagonal Goldstone mesons made out of valence or sea quark have\nequal masses. We then consider some observables known to be anomalously\nsensitive to the presence of a double pole. We find that the double-pole\nenhanced scaling violations may turn out to be rather small in practice."
    },
    {
        "anchor": "Scaling and chiral extrapolation of pion mass and decay constant with\n  maximally twisted mass QCD: We present an update of the results for pion mass and pion decay constant as\nobtained by the ETM collaboration in large scale simulations with maximally\ntwisted mass fermions and two mass degenerate flavours of light quarks. We\ndiscuss the continuum, chiral and infinite volume extrapolation of these\nquantities as well as the extraction of low energy constants, and investigate\npossible systematic uncertainties.",
        "positive": "Lattice QCD and Particle Physics: Contribution from the USQCD Collaboration to the Proceedings of the US\nCommunity Study on the Future of Particle Physics (Snowmass 2021)."
    },
    {
        "anchor": "Cellular automaton for spinor gravity in four dimensions: Certain fermionic quantum field theories are equivalent to probabilistic\ncellular automata, with fermionic occupation numbers associated to bits. We\nconstruct an automaton that represents a discrete model of spinor gravity in\nfour dimensions. Local Lorentz symmetry is exact on the discrete level and\ndiffeomorphism symmetry emerges in the naive continuum limit. Our setting could\nserve as a model for quantum gravity if diffeomorphism symmetry is realized in\nthe true continuum limit and suitable collective fields for vierbein and metric\nacquire nonvanishing expectation values. The discussion of this interesting\nspecific model reveals may key qualitative features of the continuum limit for\nprobabilistic cellular automata. This limit obtains for a very large number of\ncells if the probabilistic information is sufficiently smooth. It is associated\nto coarse graining. The automaton property that every bit configuration is\nupdated at every discrete time step to precisely one new bit configuration does\nno longer hold on the coarse grained level. A coarse grained configuration of\noccupation numbers can evolve into many different configurations with certain\nprobabilities. This characteristic feature of quantum field theories can come\nalong with the emergence of continuous space-time symmetries.",
        "positive": "NRQCD and Static Systems -- A General Variational Approach: We present initial results from Monte Carlo simulations of NRQCD-light,\nstatic-light, and NRQCD-NRQCD mesons, using a variational technique (MOST), as\npart of our ongoing calculation of the $f_{B}$ decay constant. The basis states\nfor the variational calculation are quark-antiquark operators separated by all\npossible relative distances not equivalent under the cubic group (for example,\nfor a $20^{3}$ lattice there are 286 operators). The efficacy of the method is\ndemonstrated by the good plateaus obtained for the ground state and the clean\nextraction of the wave functions of the ground and first radially excited\nstate."
    },
    {
        "anchor": "Renormalization constants of local operators within the Schr\u00f6dinger\n  functional scheme: We define, within the Schr\\\"odinger functional (SF) scheme, the matrix\nelements of the twist-2 operators corresponding to the first two moments of\nnon-singlet parton density, and the first moment of singlet parton densities.\nWe perform a lattice one-loop calculation that fixes the relation between the\nSF scheme and other common schemes and shows the main source of lattice\nartefacts. Few remarks on the improvement case are added.",
        "positive": "Evidence Against Instanton Dominance of Topological Charge Fluctuations\n  in QCD: The low-lying eigenmodes of the Dirac operator associated with typical gauge\nfield configurations in QCD encode, among other low-energy properties, the\nphysics behind the solution to the $U_A(1)$ problem (i.e. the origin of the\n$\\eta'$ mass), the nature of spontaneous chiral symmetry breaking, and the\nphysics of string-breaking, quark-antiquark pair production, and the OZI rule.\nMoreover, the space-time chiral structure of these eigenmodes reflects the\nspace-time topological structure of the underlying gauge field. We present\nevidence from lattice QCD on the local chiral structure of low Dirac eigenmodes\nleading to the conclusion that topological charge fluctuations of the QCD\nvacuum are not instanton-dominated. The result supports Witten's arguments that\ntopological charge is produced by confinement-related gauge fluctuations rather\nthan instantons."
    },
    {
        "anchor": "Domain walls and perturbation theory in high temperature gauge theory:\n  SU(2) in 2+1 dimensions: We study the detailed properties of Z_2 domain walls in the deconfined high\ntemperature phase of the d=2+1 SU(2) gauge theory. These walls are studied both\nby computer simulations of the lattice theory and by one-loop perturbative\ncalculations. The latter are carried out both in the continuum and on the\nlattice. We find that leading order perturbation theory reproduces the detailed\nproperties of these domain walls remarkably accurately even at temperatures\nwhere the effective dimensionless expansion parameter, g^2/T, is close to\nunity. The quantities studied include the surface tension, the action density\nprofiles, roughening and the electric screening mass. It is only for the last\nquantity that we find an exception to the precocious success of perturbation\ntheory. All this shows that, despite the presence of infrared divergences at\nhigher orders, high-T perturbation theory can be an accurate calculational\ntool.",
        "positive": "Nucleon matrix elements from lattice QCD with all-mode-averaging and a\n  domain-decomposed solver: an exploratory study: We study the performance of all-mode-averaging (AMA) when used in conjunction\nwith a locally deflated SAP-preconditioned solver, determining how to optimize\nthe local block sizes and number of deflation fields in order to minimize the\ncomputational cost for a given level of overall statistical accuracy. We find\nthat AMA enables a reduction of the statistical error on nucleon charges by a\nfactor of around two at the same cost when compared to the standard method. As\na demonstration, we compute the axial, scalar and tensor charges of the nucleon\nin $N_f=2$ lattice QCD with non-perturbatively O(a)-improved Wilson quarks,\nusing O(10,000) measurements to pursue the signal out to source-sink\nseparations of $t_s\\sim 1.5$ fm. Our results suggest that the axial charge is\nsuffering from a significant amount (5-10%) of excited-state contamination at\nsource-sink separations of up to $t_s\\sim 1.2$ fm, whereas the excited-state\ncontamination in the scalar and tensor charges seems to be small."
    },
    {
        "anchor": "Finite Size Scaling Analysis with Linked Cluster Expansions: Linked cluster expansions are generalized from an infinite to a finite volume\non a $d$-dimensional hypercubic lattice. They are performed to 20th order in\nthe expansion parameter to investigate the phase structure of scalar $O(N)$\nmodels for the cases of $N=1$ and $N=4$ in 3 dimensions. In particular we\npropose a new criterion to distinguish first from second order transitions via\nthe volume dependence of response functions for couplings close to but not at\nthe critical value. The criterion is applicable to Monte Carlo simulations as\nwell. Here it is used to localize the tricritical line in a $\\Phi^4 + \\Phi^6$\ntheory. We indicate further applications to the electroweak transition.",
        "positive": "Lattice Supersymmetry and Topological Field Theory: It is known that certain theories with extended supersymmetry can be\ndiscretized in such a way as to preserve an exact fermionic symmetry. In the\nsimplest model of this kind, we show that this residual supersymmetric\ninvariance is actually a BRST symmetry associated with gauge fixing an\nunderlying local shift symmetry. Furthermore, the starting lattice action is\nthen seen to be entirely a gauge fixing term. The corresponding continuum\ntheory is known to be a topological field theory. We look, in detail, at one\nexample - supersymmetric quantum mechanics which possesses two such BRST\nsymmetries. In this case, we show that the lattice theory can be obtained by\nblocking out of the continuum in a carefully chosen background metric. Such a\nprocedure will not change the Ward identities corresponding to the BRST\nsymmetries since they correspond to topological observables. Thus, at the\nquantum level, the continuum BRST symmetry is preserved in the lattice theory.\nSimilar conclusions are reached for the two-dimensional complex Wess-Zumino\nmodel and imply that all the supersymmetric Ward identities are satisfied {\\it\nexactly} on the lattice. Numerical results supporting these conclusions are\npresented."
    },
    {
        "anchor": "Measurement of the mass anomalous dimension of near-conformal adjoint\n  QCD with the gradient flow: The mass anomalous dimension is determined in SU(2) gauge theory coupled to\n$N_f$ fermions in the adjoint representation for $N_f = 2$, $3/2$, $1$ and\n$1/2$, where half-integer flavor numbers correspond to Majorana fermions. The\nnumerical method is based on gradient flow. The results show near-conformal\nbehavior for $N_f = 2$, $3/2$ and $1$. Particular emphasis is placed on $N_f =\n2$, which is relevant for a strongly interacting extension of the Standard\nModel and has been studied in several previous investigations. We check whether\nthe method is able to resolve discrepancies in earlier results for this theory.\nOverall, the method based on the gradient flow delivers reliable results in\nqualitative agreement with previously known numerical data.",
        "positive": "Series expansions of the density of states in SU(2) lattice gauge theory: We calculate numerically the density of states n(S) for SU(2) lattice gauge\ntheory on $L^4$ lattices. Small volume dependence are resolved for small values\nof S. We compare $ln(n(S))$ with weak and strong coupling expansions.\nIntermediate order expansions show a good overlap for values of S corresponding\nto the crossover. We relate the convergence of these expansions to those of the\naverage plaquette. We show that when known logarithmic singularities are\nsubtracted from $ln(n(S))$, expansions in Legendre polynomials appear to\nconverge and could be suitable to determine the Fisher's zeros of the partition\nfunction."
    },
    {
        "anchor": "$B \\to \u03c0\\ell \u03bd$ and $B_s \\to K \\ell \u03bd$ form factors and\n  $|V_{ub}|$ from 2+1-flavor lattice QCD with domain-wall light quarks and\n  relativistic heavy quarks: We calculate the $B \\to\\pi\\ell\\nu$ and $B_s \\to K \\ell\\nu$ form factors in\ndynamical lattice QCD. We use the (2+1)-flavor RBC-UKQCD gauge-field ensembles\ngenerated with the domain-wall fermion and Iwasaki gauge actions. For the $b$\nquarks we use the anisotropic clover action with a relativistic heavy-quark\ninterpretation. We analyze two lattice spacings $a \\approx 0.11, 0.086$ fm and\nunitary pion masses as light as $M_\\pi \\approx 290$ MeV. We simultaneously\nextrapolate our numerical results to the physical light-quark masses and to the\ncontinuum and interpolate in the pion/kaon energy using SU(2) \"hard-pion\"\nchiral perturbation theory. We provide complete error budgets for the form\nfactors $f_+(q^2)$ and $f_0(q^2)$ at three momenta that span the $q^2$ range\naccessible in our numerical simulations. We extrapolate these results to $q^2 =\n0$ using a model-independent $z$-parametrization and present our final form\nfactors as the $z$-coefficients and the matrix of correlations between them.\nOur results agree with other lattice determinations using staggered light\nquarks and provide important independent cross-checks. Both $B \\to\\pi\\ell\\nu$\nand $B_s \\to K \\ell\\nu$ decays enable a determination of the CKM matrix element\n$|V_{ub}|$. To illustrate this, we perform a combined $z$-fit of our numerical\n$B\\to\\pi\\ell\\nu$ form-factor data with the experimental branching-fraction\nmeasurements leaving the relative normalization as a free parameter; we obtain\n$|V_{ub}| = 3.61(32) \\times 10^{-3}$, where the error includes statistical and\nsystematic uncertainties. This approach can be applied to $B_s\\to K \\ell\\nu$\ndecay to determine $|V_{ub}|$ once the process has been measured\nexperimentally. Finally, in anticipation of future measurements, we make\npredictions for $B \\to \\pi\\ell\\nu$ and $B_s\\to K \\ell\\nu$ Standard-Model\ndifferential branching fractions and forward-backward asymmetries.",
        "positive": "Chiral unitary theory of scalar mesons in a finite volume: We develop a scheme for the extraction of the properties of the scalar mesons\n$f_0(600)$, $f_0(980)$, and $a_0(980)$ from lattice QCD data. This scheme is\nbased on a two-channel chiral unitary approach with fully relativistic\npropagators in a finite volume. In order to discuss the feasibility of finding\nthe mass and width of the scalar resonances, we analyze synthetic lattice data\nwith a fixed error assigned, and show that the framework can be indeed used for\nan accurate determination of resonance pole positions in the multi-channel\nscattering."
    },
    {
        "anchor": "Modifying the molecular dynamics action to increase topological\n  tunnelling rate for dynamical overlap fermions: We describe a new Hybrid Monte Carlo (HMC) algorithm for dynamical overlap\nfermions, which improves the rate of topological index changes by adding an\nadditional (intensive) term to the action for the molecular dynamics part of\nthe algorithm. The metropolis step still uses the exact action, so that the\nMonte Carlo algorithm still generates the correct ensemble. By tuning this new\nterm, we hope to be able to balance the acceptance rate of the HMC algorithm\nand the rate of topological index changes. We also describe how suppressing,\nbut not eliminating, the small eigenvalues of the kernel operator may improve\nthe volume scaling of the cost per trajectory for overlap HMC while still\nallowing topological index changes.\n  We test this operator on small lattices, comparing our new algorithm with an\nold overlap HMC algorithm with a slower rate of topological charge changes, and\nan overlap HMC algorithm which fixes the topology. Our new HMC algorithm more\nthan doubles the rate of topological index changes compared to the previous\nstate of the art, while maintaining the same metropolis acceptance rate. We\ninvestigate the effect of topological index changes on the local topological\ncharge density, measured using an improved field theoretic operator after heavy\nsmearing. We find that the creation and annihilation of large lumps of\ntopological charge is increased with the new algorithm.",
        "positive": "A Coupled-Cluster Formulation of Hamiltonian Lattice Field Theory: The\n  Non-Linear Sigma Model: We apply the coupled cluster method (CCM) to the Hamiltonian version of the\nlatticised O(4) non-linear sigma model. The method, which was initially\ndeveloped for the accurate description of quantum many-body systems, gives rise\nto two distinct approximation schemes. These approaches are compared with each\nother as well as with some other Hamiltonian approaches. Our study of both the\nground state and collective excitations leads to indications of a possible\nchiral phase transition as the lattice spacing is varied."
    },
    {
        "anchor": "Fixed Point Action and Topology in the CP^3 Model: We define a fixed point action in two-dimensional lattice ${\\rm CP}^{N-1}$\nmodels. The fixed point action is a classical perfect lattice action, which is\nexpected to show strongly reduced cutoff effects in numerical simulations.\nFurthermore, the action has scale-invariant instanton solutions, which enables\nus to define a correct topological charge without topological defects. Using a\nparametrization of the fixed point action for the ${\\rm CP}^{3}$ model in a\nMonte Carlo simulation, we study the topological susceptibility.",
        "positive": "Incorporating Chiral Symmetry in Extrapolations of Octet Baryon Magnetic\n  Moments: We explore methods of extrapolating lattice calculations of hadronic\nobservables to the physical regime, while respecting the constraints of chiral\nsymmetry and heavy quark effective theory. In particular, we extrapolate\nlattice results for magnetic moments of the spin-1/2 baryon octet to the\nphysical pion mass and compare with experimental measurements. The success\npreviously reported for extrapolations of the nucleon magnetic moments carries\nover to the Sigma baryons. A study of the residual discrepancies in the Xi\nbaryon moments suggests that it is important to have new simulation data with a\nmore realistic strange quark mass."
    },
    {
        "anchor": "New results on cut-off effects in spectroscopy with the fixed point\n  action: Our study on the cut-off effects in quenched light hadron spectroscopy and\npion scattering length with the fixed point action is extended by results\nobtained at a lattice spacing a=0.102 fm in a box of size L=1.8 fm. The cut-off\neffects are small, but clearly seen as the resolution is increased from a=0.153\nfm to a=0.102 fm. In the quark mass region where the errors are small and under\ncontrol, our results on the APE plot lie close to the extrapolated numbers of\nthe CP-PACS Collaboration.",
        "positive": "Two-Nucleon Systems in a Finite Volume: I present the formalism and methodology for determining the nucleon-nucleon\nscattering parameters from the finite volume spectra obtained from lattice\nquantum chromodynamics calculations. Using the recently derived energy\nquantization conditions and the experimentally determined scattering\nparameters, the bound state spectra for finite volume systems with overlap with\nthe 3S1-3D3 channel are predicted for a range of volumes. It is shown that the\nextractions of the infinite-volume deuteron binding energy and the low-energy\nscattering parameters, including the S-D mixing angle, are possible from\nLattice QCD calculations of two-nucleon systems with boosts of |P| <= 2pi\nsqrt{3}/L in volumes with spatial extents L satisfying fm <~ L <~ 14 fm."
    },
    {
        "anchor": "Fermions on random lattices: We put fermions and define the Dirac operator and spin structures on a\nrandomly triangulated 2d manifold.",
        "positive": "Pushing NRQCD to the limit: Lattice NRQCD has proven successful in describing the physics of the upsilon\nsystem and B-mesons, though some concerns arise when it is used in simulations\nof charm quarks. It is certainly possible that the NRQCD expansion is not\nconverging fast enough at this scale. We present some preliminary results on\nthe low-mass breakdown of NRQCD, in particular the behaviour of heavy\nquarkonium and heavy-light meson spectra as the bare heavy quark mass is\ndecreased well below 1, with the aim of understanding more about the\nmanifestation of this breakdown."
    },
    {
        "anchor": "Universal properties of 3d O(4) symmetric models: The scaling function\n  of the free energy density and its derivatives: We present direct representations of the scaling functions of the 3d O(4)\nmodel which are relevant for comparisons to other models, in particular QCD.\nThis is done in terms of expansions in the scaling variable\nz=t/h^{1/\\beta\\delta}. The expansions around z=0 and the corresponding\nasymptotic ones for z --> +/- infty, overlap such that no interpolation is\nneeded. We explicitly present the expansion coefficients which have been\ndetermined numerically from data of a previous high statistics simulation of\nthe O(4) model on a three-dimensional lattice of linear extension L=120. This\nallows to derive smooth representations of the first three derivatives of the\nscaling function of the free energy density, which determine universal\nproperties of up to sixth order cumulants of net charge fluctuations in QCD.",
        "positive": "Infrared Gluon Propagator from lattice QCD: results from large\n  asymmetric lattices: The infrared limit of the lattice Landau gauge gluon propagator is studied.\nWe show that the lattice data is compatible with the pure power law $(q^2)^{2\n\\kappa}$ solution of the Dyson-Schwinger equations. Using various lattice\nvolumes, the infinite volume limit for the exponent $\\kappa$ is measured.\nAlthough, the results allow $\\kappa = 0.498 - 0.525$, the lattice data favours\n$\\kappa \\sim 0.52$, which would imply a vanishing zero momentum gluon\npropagator."
    },
    {
        "anchor": "First lattice QCD study of the gluonic structure of light nuclei: The role of gluons in the structure of the nucleon and light nuclei is\ninvestigated using lattice quantum chromodynamics (QCD) calculations. The first\nmoment of the unpolarised gluon distribution is studied in nuclei up to atomic\nnumber $A=3$ at quark masses corresponding to pion masses of $m_\\pi\\sim 450$\nand $806$ MeV. Nuclear modification of this quantity defines a gluonic analogue\nof the EMC effect and is constrained to be less than $\\sim 10$% in these\nnuclei. This is consistent with expectations from phenomenological quark\ndistributions and the momentum sum rule. In the deuteron, the combination of\ngluon distributions corresponding to the $b_1$ structure function is found to\nhave a small first moment compared with the corresponding momentum fraction.\nThe first moment of the gluon transversity structure function is also\ninvestigated in the spin-1 deuteron, where a non-zero signal is observed at\n$m_\\pi \\sim 806$ MeV. This is the first indication of gluon contributions to\nnuclear structure that can not be associated with an individual nucleon.",
        "positive": "Long-distance contribution to $\u03b5_K$ from lattice QCD: A lattice QCD approach to the calculation of the long-distance contributions\nto $\\epsilon_K$ is presented. This parameter describes indirect CP violation in\n$K\\to\\pi\\pi$ decay. While the short-distance contribution to $\\epsilon_K$ can\nbe accurately calculated in terms of standard model parameters and a single\nhadronic matrix element, $B_K$, there is a long-distance part which is\nestimated to be approximately $5\\%$ of the total and is more difficult to\ndetermine. A method for determining this small but phenomenologically important\ncontribution to $\\epsilon_K$ using lattice QCD is proposed and a complete\nexploratory calculation of the contribution is presented. This exploratory\ncalculation uses an unphysical light quark mass corresponding to a 339 MeV pion\nmass and an unphysical charm quark mass of 968 MeV, expressed in the\n$\\overline{\\mathrm{MS}}$ scheme at 2 GeV. This calculation demonstrates that\nfuture work should be able to determine this long-distance contribution from\nfirst principles with a controlled error of 10\\% or less."
    },
    {
        "anchor": "The Realistic Lattice Determination of alpha_s(M_Z) Revisited: We revisit the earlier determination of alpha_s(M_Z) via perturbative\nanalyses of short-distance-sensitive lattice observables, incorporating new\nlattice data and performing a modified version of the original analysis. We\nfocus on two high-intrinsic-scale observables, log(W_11) and log(W_12), and one\nlower-intrinsic scale observable, log(W_{12}/u_0^6), finding improved\nconsistency among the values extracted using the different observables and a\nfinal result, alpha_s(M_Z)=0.1192(11), 2 sigma higher than the earlier result,\nin excellent agreement with recent non-lattice determinations and, in addition,\nin good agreement with the results of a similar, but not identical, re-analysis\nby the HPQCD Collaboration. A discussion of the relation between the two\nre-analyses is given, focussing on the complementary aspects of the two\napproaches.",
        "positive": "Excited states in lattice QCD with the stochastic LapH method: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Results in the zero-momentum bosonic I=1/2, S=1, T1u symmetry\nsector of QCD using a correlation matrix of 58 operators are presented. All\nneeded Wick contractions are efficiently evaluated using a stochastic method of\ntreating the low-lying modes of quark propagation that exploits Laplacian\nHeaviside quark-field smearing. Level identification using probe operators is\ndiscussed."
    },
    {
        "anchor": "Quark Confinement in C-periodic Cylinders at Temperatures above T_c: Due to the Gauss law, a single quark cannot exist in a periodic volume, while\nit can exist with C-periodic boundary conditions. In a C-periodic cylinder of\ncross section A = L_x L_y and length L_z >> L_x, L_y containing deconfined\ngluons, regions of different high temperature Z(3) phases are aligned along the\nz-direction, separated by deconfined- deconfined interfaces. In this geometry,\nthe free energy of a single static quark diverges in proportion to L_z. Hence,\nparadoxically, the quark is confined, although the temperature T is larger than\nT_c. At T around T_c, the confined phase coexists with the three deconfined\nphases. The deconfined-deconfined interfaces can be completely or incompletely\nwet by the confined phase. The free energy of a quark behaves differently in\nthese two cases. In contrast to claims in the literature, our results imply\nthat deconfined-deconfined interfaces are not Euclidean artifacts, but have\nobservable consequences in a system of hot gluons.",
        "positive": "High-T QCD and dimensional reduction: measuring the Debye mass: We study the high-temperature phase of SU(2) and SU(3) QCD using lattice\nsimulations of an effective 3-dimensional SU(N) + adjoint Higgs -theory,\nobtained through dimensional reduction. We investigate the phase diagram of the\n3D theory, and find that the high-T QCD phase corresponds to the metastable\nsymmetric phase of the 3D theory. We measure the Debye screening mass m_D with\ngauge invariant operators; in particular we determine the O(g^2) and O(g^3)\ncorrections to m_D. The corrections are seen to be large, modifying the\nstandard power-counting hierarchy in high temperature QCD."
    },
    {
        "anchor": "The eta ' signal from partially quenched Wilson fermions: We present new results from our ongoing study of flavor singlet pseudoscalar\nmesons in QCD. Our approach is based on (a) performing truncated eigenmode\nexpansions for the hairpin diagram and (b) incorporating the ground state\ncontribution for the connected meson propagator. First, we explain how the\ncomputations can be substantially improved by even-odd preconditioning. We\nextend previous results on early mass plateauing in the eta' channel of\ntwo-flavor full QCD with degenerate sea and valence quarks to the partially\nquenched situation. We find that early mass plateau formation persists in the\npartially quenched situation.",
        "positive": "Masses and decay constants of pions and kaons in mixed-action staggered\n  chiral perturbation theory: Lattice QCD calculations with different staggered valence and sea quarks can\nbe used to improve determinations of quark masses, Gasser-Leutwyler couplings,\nand other parameters relevant to phenomenology. We calculate the masses and\ndecay constants of flavored pions and kaons through next-to-leading order in\nstaggered-valence, staggered-sea mixed-action chiral perturbation theory. We\npresent the results in the valence-valence and valence-sea sectors, for all\ntastes. As in unmixed theories, the taste-pseudoscalar, valence-valence mesons\nare exact Goldstone bosons in the chiral limit, at non-zero lattice spacing.\nThe results reduce correctly when the valence and sea quark actions are\nidentical, connect smoothly to the continuum limit, and provide a way to\ncontrol light quark and gluon discretization errors in lattice calculations\nperformed with different staggered actions for the valence and sea quarks."
    },
    {
        "anchor": "B -> D* l nu at zero recoil: an update: We present an update of our calculation of the form factor for B -> D* l nu\nat zero recoil, with higher statistics and finer lattices. As before, we use\nthe Fermilab action for b and c quarks, the asqtad staggered action for light\nvalence quarks, and the MILC ensembles for gluons and light quarks\n(L\\\"uscher-Weisz married to 2+1 rooted staggered sea quarks). In this update,\nwe have reduced the total uncertainty on F(1) from 2.6% to 1.7%.\n  At Lattice2010 we presented a still-blinded result, but this writeup includes\nthe unblinded result from the September 2010 CKM workshop.",
        "positive": "The Leutwyler-Smilga relation on the lattice: According to the Leutwyler-Smilga relation, in Quantum Chromodynamics (QCD)\nthe topological susceptibility vanishes linearly with the quark masses.\nCalculations of the topological susceptibility in the context of lattice QCD,\nextrapolated to zero quark masses, show a remnant non-zero value as a lattice\nartefact. Employing the Atiyah-Singer theorem in the framework of Symanzik's\neffective action and chiral perturbation theory, we show the validity of the\nLeutwyler-Smilga relation in lattice QCD with lattice artefacts of order $a^2$\nin the lattice spacing $a$."
    },
    {
        "anchor": "String breaking and monopoles: The string breaking is discussed in U(1)^{N-1} Abelian effective theories of\nQCD. When a screening is expected, the static potential shows a flattening in\nthe long-range region and a linear behavior in the intermediate region. We show\nwhy the screening is better observed in the Polyakov-loop correlators than in\nthe Wilson loops. The breaking of the adjoint string is explained without the\nZ(N) picture.",
        "positive": "Ising Spins on a Gravitating Sphere: We investigated numerically an Ising model coupled to two-dimensional\nEuclidean gravity with spherical topology, using Regge calculus with the $dl/l$\npath-integral measure to discretize the gravitational interaction. Previous\nstudies of this system with toroidal topology have shown that the critical\nbehavior of the Ising model remains in the flat-space Onsager universality\nclass, contrary to the predictions of conformal field theory and matrix models.\nImplementing the spherical topology as triangulated surfaces of\nthree-dimensional cubes, we find again strong evidence that the critical\nexponents of the Ising transition are consistent with the Onsager values, and\nthat KPZ exponents are definitely excluded."
    },
    {
        "anchor": "Exclusive semileptonic $B_s\\to K \\ell \u03bd$ decays on the lattice: Semileptonic $B_s \\to K \\ell \\nu$ decays provide an alternative $b$-decay\nchannel to determine the CKM matrix element $|V_{ub}|$, and to obtain a\n$R$-ratio to investigate lepton-flavor-universality violations. Results for the\nCKM matrix element may also shed light on the discrepancies seen between\nanalyses of inclusive or exclusive decays. We calculate the decay form factors\nusing lattice QCD with domain-wall light quarks and a relativistic $b$-quark.\nWe analyze data at three lattice spacings with unitary pion masses down to\n$268\\,\\mathrm{MeV}$. Our numerical results are interpolated/extrapolated to\nphysical quark masses and to the continuum to obtain the vector and scalar form\nfactors $f_+(q^2)$ and $f_0(q^2)$ with full error budgets at $q^2$ values\nspanning the range accessible in our simulations. We provide a possible\nexplanation of tensions found between results for the form factor from\ndifferent lattice collaborations. Model- and truncation-independent\n$z$-parameterization fits following a recently proposed Bayesian-inference\napproach extend our results to the entire allowed kinematic range. Our results\ncan be combined with experimental measurements of $B_s \\to D_s$ and $B_s\\to K$\nsemileptonic decays to determine $|V_{ub}|=3.8(6)\\times 10^{-3}$. The error is\ncurrently dominated by experiment. We compute differential branching fractions\nand two types of $R$ ratios, the one commonly used as well as a variant better\nsuited to test lepton-flavor universality.",
        "positive": "Gauge engineering and propagators: Beyond perturbation theory gauge-fixing becomes more involved due to the\nGribov-Singer ambiguity: The appearance of additional gauge copies requires to\ndefine a procedure how to handle them. For the case of Landau gauge the\nstructure and properties of these additional gauge copies will be investigated.\nBased on these properties gauge conditions are constructed to account for these\ngauge copies.\n  The dependence of the propagators on the choice of these complete\ngauge-fixings will then be investigated using lattice gauge theory for\nYang-Mills theory. It is found that the implications for the infrared, and to\nsome extent mid-momentum behavior, can be substantial. In going beyond the\nYang-Mills case it turns out that the influence of matter can generally not be\nneglected. This will be briefly discussed for various types of matter."
    },
    {
        "anchor": "Scale Setting for CLS 2+1 Simulations: We present an update of the scale setting for $N_f=2+1$ flavor QCD using\ngradient flow scales and pseudo-scalar decay constants. We analyze the latest\nensembles with $2+1$ flavors of non-perturbatively improved Wilson fermions\ngenerated by CLS for improved precision. Special care is taken to correct for\nmistuning by measuring directly the mass derivatives of the various\nobservables. We determine $t_0$ with input taken from a combination of leptonic\ndecay rates of the Pion and the Kaon.",
        "positive": "On the type of the temperature phase transition in phi-4 model: The temperature induced phase transition is investigated in the one-component\nscalar field \\phi^4 model on a lattice by using Monte Carlo simulations. Using\nthe GPGPU technology a huge amount of data is collected that gives a\npossibility to determine the Linde-Weinberg low bound on the coupling constant\n\\lambda_0 and investigate the type of the phase transition for a wide interval\nof coupling values. It is found that for the values of \\lambda close to this\nbound a weak-first-order phase transition happens. It converts into a second\norder phase transition with the increase of \\lambda. A comparison with analytic\ncalculations in continuum field theory and lattice simulations obtained by\nother authors is given."
    },
    {
        "anchor": "Conformal fixed point of SU(3) gauge theory with 12 fundamental fermions: We study the infrared properties of SU(3) gauge theory coupled to 12 massless\nDirac fermions in the fundamental representation. The renormalized running\ncoupling constant is calculated in the Twisted Polyakov loop scheme on the\nlattice. From the step-scaling analysis, we find that the infrared behavior of\nthe theory is governed by a non-trivial fixed point.",
        "positive": "Step scaling in coordinate space: running of the quark mass: We perform a benchmark study of the step scaling procedure for the ratios of\nrenormalization constants extracted from position space correlation functions.\nWe work in the quenched approximation and consider the pseudoscalar, scalar,\nvector and axial vector bilinears. The pseudoscalar/scalar cases allow us to\nobtain the non-perturbative running of the quark mass over a wide range of\nenergy scales - from around 17 GeV to below 1.5 GeV - which agrees well with\nthe 4-loop prediction of continuum perturbation theory. We find that step\nscaling is feasible in X-space and we discuss its advantages and potential\nproblems."
    },
    {
        "anchor": "Gauge cooling for the singular-drift problem in the complex Langevin\n  method --- an application to finite density QCD: We study full QCD at finite density and low temperature with light quark mass\nusing the complex Langevin method. Since the singular drift problem turns out\nto be mild on a $4^3 \\times 8$ lattice we use, the gauge cooling is performed\nonly to control the unitarity norm in this exploratory study. We report on our\npreliminary data obtained from the complex Langevin simulation up to certain\nLangevin time. While the data are still noisy due to lack of statistics, the\nonset of the baryon number density seems to occur at larger $\\mu$ than half the\npion mass, which is the value for the phase quenched QCD. The validity of our\nsimulation is tested by the recently proposed criterion based on the\nprobability distribution of the drift term.",
        "positive": "Pseudo-Character Expansions for U(N)-Invariant Spin Models on CP^{N-1}: We define a set of orthogonal functions on the complex projective space\nCP^{N-1}, and compute their Clebsch-Gordan coefficients as well as a large\nclass of 6-j symbols. We also provide all the needed formulae for the\ngeneration of high-temperature expansions for U(N)-invariant spin models\ndefined on CP^{N-1}."
    },
    {
        "anchor": "Non-perturbative computation of the bubble nucleation rate in the cubic\n  anisotropy model: At first order phase transitions the transition proceeds through droplet\nnucleation and growth. We discuss a lattice method for calculating the droplet\nnucleation rate, including the complete dynamical factors. The method is\nespecially suitable for very strongly suppressed droplet nucleation, which is\noften the case in physically interesting transitions. We apply the method to\nthe 3-dimensional cubic anisotropy model in a parameter range where the model\nhas a radiatively induced strong first order phase transition, and compare the\nresults with analytical approaches.",
        "positive": "A lattice potential investigation of quark mass and volume dependence of\n  the $\u03a5$ spectrum: We investigate bottomonia splittings by solving a Schrodinger-Pauli-type\nequation with parametrisations of QCD potentials around those that have been\ndetermined previously in lattice simulations. This is done both, in the\ncontinuum and on finite lattices with resolutions ranging from a=0.2 fm down to\na=0.025 fm and extent of up to 12 fm or 144^3 lattice points. We find a strong\ndependence of some splittings, in particular the 2S-1S and 1P-1S splittings, on\nboth the quark mass and the short range form of the static potential in the\nneighbourhood of the bottom quark mass, while splittings such as 3S-2S and\n2P-2S show reduced dependence on the short distance potential. We conclude that\nthe quenched quarkonium spectrum cannot be matched to experiment with a simple\nredefinition of the lattice spacing. We investigate the size of relativistic\ncorrections as a function of the quark mass. Finite size effects are shown to\ndie out rather rapidly as the volume is increased, and we demonstrate the\nrestoration of rotational symmetry as the continuum limit is taken."
    },
    {
        "anchor": "Four-loop free energy for the 2D O(n) nonlinear sigma-model with 0-loop\n  and 1-loop Symanzik improved actions: We calculate up to four loops the free energy of the two-dimensional (2D)\nO(n) nonlinear sigma-model regularized on the lattice with the 0-loop and\n1-loop Symanzik improved actions. An effective coupling constant based on this\ncalculation is defined.",
        "positive": "Aoki Phases in the Lattice Gross-Neveu Model with Flavored Mass terms: We investigate the parity-broken phase structure for staggered and naive\nfermions in the Gross-Neveu model as a toy model of QCD. We consider a\ngeneralized staggered Gross-Neveu model including two types of four-point\ninteractions. We use generalized mass terms to split the doublers for both\nstaggered and naive fermions. The phase boundaries derived from the gap\nequations show that the mass splitting of tastes results in an Aoki phase both\nin the staggered and naive cases. We also discuss the continuum limit of these\nmodels and explore taking the chirally-symmetric limit by fine-tuning a mass\nparameter and two coupling constants. This supports the idea that in lattice\nQCD we can derive one- or two-flavor staggered fermions by tuning the mass\nparameter, which are likely to be less expensive than Wilson fermions in QCD\nsimulation."
    },
    {
        "anchor": "The Effectiveness of Non-Perturbative O(a) Improvement in Lattice QCD: The ALPHA collaboration has determined the O(a) improved Wilson quark action\nfor lattice spacings $a\\leq 0.1$ fm, in the quenched approximation. We extend\nthis result to coarser lattices, $a\\leq 0.17$ fm, and calculate the hadron\nspectrum on them. The large range of lattice spacings obtained by combining our\nresults with earlier ones on finer lattices, allow us to present a convincing\ndemonstration of the efficiency of non-perturbative O(a) improvement. We find\nthat scaling violations of the hadron masses studied drop from 30-40% for the\nunimproved Wilson action on the coarsest lattice to only 2-3%.",
        "positive": "Moments of parton evolution probabilities on the lattice within the\n  Schroedinger functional scheme: We define, within the Schroedinger functional scheme (SF), the matrix\nelements of the twist-2 operators corresponding to the first two moments of\nnon-singlet parton densities. We perform a lattice one-loop calculation that\nfixes the relation between the SF scheme and other common schemes and shows the\nmain source of lattice artefacts. This calculation sets the basis for a\nnumerical evaluation of the non-perturbative running of parton densities."
    },
    {
        "anchor": "More on Electric and Magnetic Fluxes in SU(2): The free energies of static charges and center monopoles are given by their\nfluxes. While electric fluxes show the universal behaviour of the deconfinement\ntransition, the monopole free energies vanish in the thermodynamic limit at all\ntemperatures and are thus irrelevant for the transition. Magnetic fluxes may,\nhowever, be used to measure the topological susceptibility without cooling.",
        "positive": "Bottomonium in the plasma: lattice results: We present results on the heavy quarkonium spectrum and spectral functions\nobtained by performing large-scale simulations of QCD for temperatures ranging\nfrom about 100 to 500 MeV, in the same range as those explored by LHC\nexperiments. We discuss our method and perspectives for further improvements\ntowards the goal of full control over the many systematic uncertainties of\nthese studies."
    },
    {
        "anchor": "Multi-hadron-state contamination in nucleon observables from chiral\n  perturbation theory: Multi-particle states with additional pions are expected to be a\nnon-negligible source of the excited-state contamination in lattice simulations\nat the physical point. It is shown that baryon chiral perturbation theory\n(ChPT) can be employed to calculate the contamination due to two-particle\nnucleon-pion states in various nucleon observables. Results to leading order\nare presented for the nucleon axial, tensor and scalar charge and three Mellin\nmoments of parton distribution functions: the average quark momentum fraction,\nthe helicity and the transversity moment. Taking into account experimental and\nphenomenological results for the charges and moments the impact of the\nnucleon-pion-states on lattice estimates for these observables can be\nestimated. The nucleon-pion-state contribution leads to an overestimation of\nall charges and moments obtained with the plateau method. The overestimation is\nat the 5-10% level for source-sink separations of about 2 fm. Existing lattice\ndata is not in conflict with the ChPT predictions, but the comparison suggests\nthat significantly larger source-sink separations are needed to compute the\ncharges and moments with few-percent precision.",
        "positive": "Distribution Amplitudes of Vector Mesons: Results are presented for the lowest moment of the distribution amplitude for\nthe K-star vector meson. Both longitudinal and transverse moments are\ninvestigated. We use two flavours of O(a) improved Wilson fermions, together\nwith a non-perturbative renormalisation of the matrix element."
    },
    {
        "anchor": "Light baryon spectrum using improved interpolating operators: Energies for excited light baryons are computed in quenched QCD with a pion\nmass of 490 MeV. Operators used in the simulations include local operators and\nthe simplest nonlocal operators that have nontrivial orbital structures. All\noperators are designed with the use of Clebsch-Gordan coefficients of the\noctahedral group so that they transform irreducibly under the group rotations.\nMatrices of correlation functions are computed for each irreducible\nrepresentation, and then the variational method is applied to separate mass\neigenstates. We obtained 17 states for isospin 1/2 and 11 states for isospin\n3/2 in various spin-parity channels including $J^P=5/2^\\pm$. The pattern of the\nlowest-lying energies from each irrep is discussed. We use anisotropic lattices\nof volume $24^3\\times 64$ with temporal lattice spacing $a_t^{-1}=6.05$ GeV\nwith renormalized anisotropy $\\xi=3.0$.",
        "positive": "Charmonium correlators and spectral functions at finite temperature: We study charmonium correlators and spectral functions in quenched QCD, using\nClover improved Wilson fermions on very fine (0.015 fm) isotropic lattices at\n0.75 Tc and 1.5 Tc. We use a new approach to distinguish the zero mode\ncontribution from the other contributions. Once this is removed, we find that\nthe ratios of correlators to reconstructed correlators remain almost unity at\nall distances. The ground state peaks of spectral functions obtained at 0.75 Tc\nare reliable and robust. The present accuracy and limited number of points in\nthe temporal direction at 1.5 Tc do not allow for a reliable conclusion about a\npossible melting of charmonium states in the QGP."
    },
    {
        "anchor": "Renormalization of the Yukawa and Quartic Couplings in $\\mathcal{N} = 1$\n  Supersymmetric QCD: In this work we perform calculations in order to determine the\nrenormalization factors and the mixing coefficients of the Yukawa and the\nquartic couplings in $\\mathcal{N} = 1$ Supersymmetric QCD. The Yukawa couplings\ndescribe the interactions between gluino, quark and squark fields whereas the\nquartic couplings describe four-squark interactions. We discretize the action\non a Euclidean lattice using the Wilson formulation for the gluino, quark and\ngluon fields; for squark fields (scalar fields) we employ na\\\"ive\ndiscretization. At the quantum level Yukawa and quartic interactions suffer\nfrom mixing with other operators which have the same transformation properties.\nExploiting parity and charge conjugation symmetries of the Supersymmetric QCD\naction, we reduce the allowed mixing patterns. We compute, perturbatively to\none-loop and to the lowest order in the lattice spacing, the relevant\nthree-point Green's functions so as to fine tune the Yukawa couplings and the\nrelevant four-point Green's functions to fine tune the quartic couplings. We\nuse both dimensional and lattice regularizations as required for implementing\nthe Modified Minimal Subtraction scheme ($\\overline{\\rm MS}$).",
        "positive": "Two-link Staggered Quark Smearing in QUDA: Gauge covariant smearing based on the 3D lattice Laplacian can be used to\ncreate extended operators that have better overlap with hadronic ground states.\nFor staggered quarks, we make use of two-link parallel transport to preserve\ntaste properties. We have implemented the procedure in QUDA. We present the\nperformance of this code on the NVIDIA A100 GPUs in Indiana University's Big\nRed 200 supercomputer and on the AMD MI250X GPUs in Oak Ridge Leadership\nComputer Facility's (OLCF's) Crusher and discuss its scalability. We also study\nthe performance improvement from using NVSHMEM on OLCF's Summit. Reusing\nprecomputed two-link products for all sources and sinks, it reduces the total\nsmearing time for a baryon correlator measurement by a factor of 100-120 as\ncompared with the original MILC code and reduces the overall time by 60-70%."
    },
    {
        "anchor": "Applications of chiral perturbation theory to lattice QCD: These notes contain the written version of lectures given at the 2009 Les\nHouches Summer School \"Modern perspectives in lattice QCD: Quantum field theory\nand high performance computing.\" The goal is to provide a pedagogical\nintroduction to the subject, and not a comprehensive review. Topics covered\ninclude a general introduction, the inclusion of scaling violations in chiral\nperturbation theory, partial quenching and mixed actions, chiral perturbation\ntheory with heavy kaons, and the effects of finite volume, both in the p- and\nepsilon-regimes.",
        "positive": "Kernel controlled real-time Complex Langevin simulation: This study explores the utility of a kernel in complex Langevin simulations\nof quantum real-time dynamics on the Schwinger-Keldysh contour. We give several\nexamples where we use a systematic scheme to find kernels that restore correct\nconvergence of complex Langevin. The schemes combine prior information we know\nabout the system and the correctness of convergence of complex Langevin to\nconstruct a kernel. This allows us to simulate up to $1.5\\beta$ on the\nreal-time Schwinger-Keldysh contour with the $0+1$ dimensional anharmonic\noscillator using $m=1,\\lambda=24$, which was previously unattainable using the\ncomplex Langevin equation."
    },
    {
        "anchor": "Negative-Parity Baryon Spectroscopy: Results are reported for the first calculation of the low-lying spin-1/2\nodd-parity octet baryon masses using ${\\cal O}(a^2)$ improved gluon and fermion\nactions. Methods for removing even-parity ground-state contaminations from the\ntwo-point correlation functions at zero and finite momenta are outlined. We\ninvestigate the properties of two odd-parity interpolating fields based on the\nestablished interpolating fields for the nucleon ground state. Isolation of the\nlowest-lying odd-parity state appears to be sufficient to begin exploring\nodd-parity $N \\to N^*$ electromagnetic transition form factors.",
        "positive": "Abelianization of QCD in the Maximally Abelian Gauge and the Nambu-'t\n  Hooft Picture for Color Confinement: We study the Nambu-'t Hooft picture for color confinement in terms of the\nabelianization of QCD and monopole condensation in the maximally abelian (MA)\ngauge. In the MA gauge in the Euclidean metric, the off-diagonal gluon\namplitude is strongly suppressed, and then the off-diagonal gluon phase shows\nstrong randomness, which leads to rapid reduction of the off-diagonal gluon\ncorrelation. In SU(2) and SU(3) lattice QCD in the MA gauge with the abelian\nLandau gauge, the Euclidean gluon propagator indicates a large effective mass\nof the off-diagonal gluon as $M_{\\rm off} \\simeq 1 {\\rm GeV}$ in the\nintermediate distance as $0.2{\\rm fm} \\le r \\le 0.8{\\rm fm}$. Due to the\ninfrared inactiveness of off-diagonal gluons, infrared QCD is well abelianized\nlike nonabelian Higgs theories in the MA gauge. We investigate the\ninter-monopole potential and the dual gluon field $B_\\mu$ in the MA gauge, and\nfind longitudinal magnetic screening with $m_B \\simeq$ 0.5 GeV in the infrared\nregion, which indicates the dual Higgs mechanism by monopole condensation. We\ndefine the ``gluonic Higgs scalar field'' providing the MA projection, and find\nthe correspondence between its hedgehog singularity and the monopole location\nin lattice QCD."
    },
    {
        "anchor": "Continuous Time Monte Carlo for Lattice QCD in the Strong Coupling Limit: We present results for lattice QCD in the limit of infinite gauge coupling,\nobtained from a worm-type Monte Carlo algorithm on a discrete spatial lattice\nbut with continuous Euclidean time. This is obtained by sending both the\nanisotropy parameter gamma^2 \\sim a/a_t and the number of time-slices N_\\tau to\ninfinity, keeping the ratio \\gamma^2/N_\\tau \\sim aT fixed. The obvious gain is\nthat no continuum extrapolation N_\\tau -> \\infty has to be carried out.\nMoreover, the algorithm is faster and the sign problem disappears. We compare\nour computations with those on discrete lattices. We determine the phase\ndiagram as a function of temperature and baryon chemical potential.",
        "positive": "Topology in 4D simplicial quantum gravity: We simulate 4d simplicial gravity for three topologis S4, S3xS1, (S1)^4 and\nshow that the free energy for these three fixed topology ensembles is the same\nin the thermodynamic limit. We show, that the next-to-leading order\ncorrections, at least away from the critical point, can be described by\nkinematic sources."
    },
    {
        "anchor": "Vacuum Entanglement Harvesting in the Ising Model: The low-energy states of quantum many body systems, such as spin chains, are\nentangled. Using tensor network computations, we demonstrate a protocol that\ndistills Bell pairs out of the ground state of the prototypical\ntransverse-field Ising model. We explore the behavior of rate of entanglement\ndistillation in various phases, and possible optimizations of the protocol.\nFinally, we comment on the protocol as we approach quantum criticality defining\na continuum field theory.",
        "positive": "QCD in the heavy dense regime for general $N_c$: On the existence of\n  quarkyonic matter: Lattice QCD with heavy quarks reduces to a three-dimensional effective theory\nof Polyakov loops, which is amenable to series expansion methods. We analyse\nthe effective theory in the cold and dense regime for a general number of\ncolours, $N_c$. In particular, we investigate the transition from a hadron gas\nto baryon condensation. For any finite lattice spacing, we find the transition\nto become stronger, i.e. ultimately first-order, as $N_c$ is made large.\nMoreover, in the baryon condensed regime, we find the pressure to scale as\n$p\\sim N_c$ through three orders in the hopping expansion. Such a phase differs\nfrom a hadron gas with $p\\sim N_c^0$, or a quark gluon plasma, $p\\sim N_c^2$,\nand was termed quarkyonic in the literature, since it shows both baryon-like\nand quark-like aspects. A lattice filling with baryon number shows a rapid and\nsmooth transition from condensing baryons to a crystal of saturated quark\nmatter, due to the Pauli principle, and is consistent with this picture. For\ncontinuum physics, the continuum limit needs to be taken before the large $N_c$\nlimit, which is not yet possible in practice. However, in the controlled range\nof lattice spacings and $N_c$-values, our results are stable when the limits\nare approached in this order. We discuss possible implications for physical\nQCD."
    },
    {
        "anchor": "On cutoff effects in lattice QCD from short to long distances: We discuss kinematical enhancements of cutoff effects at short and\nintermediate distances. Starting from a pedagogical example with periodic\nboundary conditions, we switch to the case of the Schroedinger Functional,\nwhere the theoretical analysis is checked by precise numerical data with Nf=2\ndynamical O(a)-improved Wilson quarks. Finally we present an improved\ndetermination of the renormalization of the axial current in that theory.",
        "positive": "Prediction and compression of lattice QCD data using machine learning\n  algorithms on quantum annealer: We present regression and compression algorithms for lattice QCD data\nutilizing the efficient binary optimization ability of quantum annealers. In\nthe regression algorithm, we encode the correlation between the input and\noutput variables into a sparse coding machine learning algorithm. The trained\ncorrelation pattern is used to predict lattice QCD observables of unseen\nlattice configurations from other observables measured on the lattice. In the\ncompression algorithm, we define a mapping from lattice QCD data of\nfloating-point numbers to the binary coefficients that closely reconstruct the\ninput data from a set of basis vectors. Since the reconstruction is not exact,\nthe mapping defines a lossy compression, but, a reasonably small number of\nbinary coefficients are able to reconstruct the input vector of lattice QCD\ndata with the reconstruction error much smaller than the statistical\nfluctuation. In both applications, we use D-Wave quantum annealers to solve the\nNP-hard binary optimization problems of the machine learning algorithms."
    },
    {
        "anchor": "Regge gravity on general triangulations: We investigate quantum gravity in four dimensions using the Regge approach on\ntriangulations of the four-torus with general, non-regular incidence matrices.\nWe find that the simplicial lattice tends to develop spikes for vertices with\nlow coordination numbers even for vanishing gravitational coupling. Different\nto the regular, hypercubic lattices almost exclusively used in previous\nstudies, we find now that the observables depend on the measure. Computations\nwith nonvanishing gravitational coupling still reveal the existence of a region\nwith well-defined expectation values. However, the phase structure depends on\nthe triangulation. Even with additional higher- order terms in the action the\ncritical behavior of the system changes with varying (local) coordination\nnumbers.",
        "positive": "Classical solutions in lattice gauge theories: The solutions of the classical equations of motion on a periodic lattice are\nfound which correspond to abelian single and double Dirac sheets. These\nsolutions exist also in non--abelian theories. Possible applications of these\nsolutions to the calculation of gauge dependent and gauge invariant observables\nare discussed."
    },
    {
        "anchor": "SU(2) gluon propagators from the lattice - a preview: High accuracy numerical results for the SU(2) gluonic form factor are\npreviewed for the case of Landau gauge. I focus on the information of quark\nconfinement encoded in the gluon propagator.",
        "positive": "Random Lattice QCD and chiral effective theories: Resent developments in the Random Matrix and Random Lattice Theories give a\npossibility to find low-energy theorems for many physical models in the\nBorn-Infeld form. In our approach that based on the Random Lattice\nregularization of QCD we try to used the similar ideas in the low-energy baryon\nphysics for finding of the low-energy theory for the chiral fields in the\nstrong-coupling regime."
    },
    {
        "anchor": "Progress in lattice chiral gauge theories: Some key features of continuum chiral fermions are shown to be satisfied by\nthe overlap.",
        "positive": "Lower Higgs boson mass bounds from a chirally invariant lattice\n  Higgs-Yukawa model with overlap fermions: We study the coupling parameter dependence of the Higgs boson mass in a\nchirally invariant lattice Higgs-Yukawa model emulating the same Yukawa\ncoupling structure as in the Higgs-fermion sector of the Standard Model.\nEventually, the aim is to establish non-perturbative upper and lower Higgs\nboson mass bounds derived from first principles, in particular not relying on\nvacuum stability considerations for the latter case. Here, we present our\nlattice results for the lower Higgs boson mass bound at several values of the\ncutoff and compare them to corresponding analytical calculations based on the\neffective potential as obtained from lattice perturbation theory. Furthermore,\nwe give a brief outlook towards the calculation of the upper Higgs boson mass\nbound."
    },
    {
        "anchor": "Least-squares optimized polynomials for fermion simulations: Least-squares optimized polynomials are discussed which are needed in the\ntwo-step multi-bosonic algorithm for Monte Carlo simulations of quantum field\ntheories with fermions. A recurrence scheme for the calculation of necessary\ncoefficients in the recursion and for the evaluation of these polynomials is\nintroduced.",
        "positive": "Application of Maximum Entropy Method to Dynamical Fermions: The Maximum Entropy Method is applied to dynamical fermion simulations of the\n(2+1)-dimensional Nambu-Jona-Lasinio model. This model is particularly\ninteresting because at T=0 it has a broken phase with a rich spectrum of\nmesonic bound states and a symmetric phase where there are resonances, and\nhence the simple pole assumption of traditional fitting procedures breaks down.\nWe present results extracted from simulations on large lattices for the\nspectral functions of the elementary fermion, the pion, the sigma, the massive\npseudoscalar meson and the symmetric phase resonances."
    },
    {
        "anchor": "Nucleon spectroscopy using multi-particle operators: The role of 5-quark operators in extracting the nucleon excited state\nspectrum via correlation matrix techniques is explored. In particular, the\ncoupling of meson-baryon operators to nucleon resonance states and scattering\nstates is studied. Results are presented for 2+1 flavour dynamical ensembles in\nboth the positive and negative parity channels. Fitting a single-state ansatz\nto the eigenstate-projected correlators provides robust energies for the\nlow-lying spectrum that are essentially invariant across a variety of different\noperator bases. In particular, the resonant state energies obtained both with\nand without the use of meson-baryon operators agree, demonstrating that\nresonance energies can be reliably extracted solely using 3-quark operators.",
        "positive": "Glueball wavefunctions: We measure Coulomb-gauge wavefunctions of the scalar and tensor glueballs in\nSU(2) Yang-Mills. The problem of contamination by flux states is discussed, and\na new analysis method described. The large size of the tensor glueball is\nconfirmed. Preliminary results in the deconfined phase show no significant\nchanges."
    },
    {
        "anchor": "Finite-volume Correction to the Pion Decay Constant in the\n  Epsilon-Regime: In the chiral limit of QCD, the pion decay constant F can be extracted from\nlattice gauge theory by means of a coupling to isospin chemical potential. Here\nwe compute the leading correction due to finite volume in the epsilon-expansion\nof chiral perturbation theory. A comparison is made to recent Monte Carlo data.",
        "positive": "Studies of B and B_s Meson Leptonic Decays with NRQCD Bottom and HISQ\n  Light/Strange Quarks: We present a progress report on new calculations of B and B_s meson decay\nconstants employing NRQCD heavy and HISQ light valence quarks and using MILC\nN_f = 2+1 AsqTad lattices. Bare quark masses have been retuned in accord with\nHPQCD's new r_1 scale. We find significant reductions in discretization effects\ncompared to previous calculations with AsqTad light valence quarks. Matching of\nthe NRQCD/HISQ heavy-light axial vector current is carried out at one-loop\norder including all relevant dimension 4 current corrections."
    },
    {
        "anchor": "Sphaleron transition rate at high temperature in the 1+1 D abelian Higgs\n  model: New results for the rate are presented using the canonical ensemble in the\nclassical approximation on a spatial lattice. We find that the rate at high\ntemperatures is proportional to $T^2$, and strongly dependent on the lattice\nspacing $a$. We conclude that a better effective action is needed for the\nclassical approximation.",
        "positive": "Topics in Non-Perturbative QCD: General aspects of non-perturbative field theory are discussed.The definition\nof condensates is analysed.Mechanisms of color confinement are rewieved."
    },
    {
        "anchor": "Where do perturbative and non-perturbative QCD meet?: We computed the static potential and Wilson loops to $O(\\alpha^2)$ in\nperturbation theory for different lattice quark and gluon actions. In general,\nwe find short distance lattice data to be well described by ``boosted\nperturbation theory''. For Wilson-type fermions at present-day quark masses and\nlattice spacings agreement within 10% between measured ``$\\beta$-shifts'' and\nthose predicted by perturbation theory is found. We comment on prospects for a\ndetermination of the real world QCD running coupling.",
        "positive": "The Running Coupling from Lattice Gauge Theory: From an accurate determination of the inter-quark potential, one can study\nthe running coupling constant for a range of $R$-values and hence estimate the\nscale $\\Lambda_{\\msbar} $. Detailed results are presented for $SU(2)$ pure\ngauge theory to illustrate the method."
    },
    {
        "anchor": "Lattice Calculations of Nucleon Electromagnetic Form Factors at Large\n  Momentum Transfer: In this work, we report a novel technique in lattice QCD for studying the\nhigh momentum-transfer region of nucleon form factors. These calculations could\ngive important theoretical input to experiments, such as those of JLab's 12-GeV\nprogram and studies of nucleon deformation. There is an extensive history of\nform-factor calculations on the lattice, primarily with ground states for both\nthe initial and final state. However, determining form factors at large\nmomentum transfer ($Q^2$) has been difficult due to large statistical and\nsystematic errors in this regime. We study the nucleon form factors using three\npion masses with both quenched and 2+1-flavor anisotropic lattice\nconfigurations with $Q^2$ as large as $6 GeV^2$. These form factors are further\nprocessed to obtain transverse charge and magnetization densities across\n2-dimensional impact-parameter space. Our approach can be applied to isotropic\nlattices and lattices with smaller lattice spacing to calculate even\nlarger-$Q^2$ form factors.",
        "positive": "Supersymmetric QCD on the Lattice: An Exploratory Study: We perform a pilot study of the perturbative renormalization of a\nSupersymmetric gauge theory with matter fields on the lattice. As a specific\nexample, we consider Supersymmetric ${\\cal N}{=}1$ QCD (SQCD). We study the\nself-energies of all particles which appear in this theory, as well as the\nrenormalization of the coupling constant. To this end we compute,\nperturbatively to one-loop, the relevant two-point and three-point Green's\nfunctions using both dimensional and lattice regularizations. Our lattice\nformulation involves the Wilson discretization for the gluino and quark fields;\nfor gluons we employ the Wilson gauge action; for scalar fields (squarks) we\nuse na\\\"ive discretization. The gauge group that we consider is $SU(N_c)$,\nwhile the number of colors, $N_c$, the number of flavors, $N_f$, and the gauge\nparameter, $\\alpha$, are left unspecified.\n  We obtain analytic expressions for the renormalization factors of the\ncoupling constant ($Z_g$) and of the quark ($Z_\\psi$), gluon ($Z_u$), gluino\n($Z_\\lambda$), squark ($Z_{A_\\pm}$), and ghost ($Z_c$) fields on the lattice.\nWe also compute the critical values of the gluino, quark and squark masses.\nFinally, we address the mixing which occurs among squark degrees of freedom\nbeyond tree level: we calculate the corresponding mixing matrix which is\nnecessary in order to disentangle the components of the squark field via an\nadditional finite renormalization."
    },
    {
        "anchor": "Calculation of fermion loops for $\u03b7^\\prime$ and nucleon scalar and\n  electromagnetic form factors: The exact evaluation of the disconnected diagram contributions to the\nflavor-singlet pseudoscalar meson mass, the nucleon sigma term and the nucleon\nelectromagnetic form factors, is carried out utilizing GPGPU technology with\nthe NVIDIA CUDA platform. The disconnected loops are also computed using\nstochastic methods with several noise reduction techniques. Various dilution\nschemes as well as the truncated solver method are studied. We make a\ncomparison of these stochastic techniques to the exact results and show that\nthe number of noise vectors depends on the operator insertion in the fermionic\nloop.",
        "positive": "Signals of confinement in Green functions of SU(2) Yang-Mills theory: The vortex picture of confinement is employed to explore the signals of\nconfinement in Yang-Mills Green functions. By using SU(2) lattice gauge theory,\nit has been well established that the removal of the center vortices from the\nlattice configurations results in the loss of confinement. The running coupling\nconstant, the gluon and the ghost form factors are studied in Landau gauge for\nboth cases, the full and the vortex removed theory. In the latter case, a\nstrong suppression of the running coupling constant and the gluon form factor\nat low momenta is observed. At the same time, the singularity of the ghost form\nfactor at vanishing momentum disappears. This observation establishes an\nintimate correlation between the ghost singularity and confinement. The result\nalso shows that a removal of the vortices generates a theory for which\nZwanziger's horizon condition for confinement is no longer satisfied."
    },
    {
        "anchor": "Hybrid Molecular Dynamics for Lattice Supersymmetry: We present the first results obtained with a Hybrid Molecular Dynamics\nalgorithm applied to an $N=1$ SU(2) Super-Yang--Mills on the lattice. We derive\nthe Hamilton equations of motion for the system with Wilson gluinos and present\npreliminary results on small lattices.",
        "positive": "Pseudoscalar meson physics with four dynamical quarks: We present preliminary results for light, strange and charmed pseudoscalar\nmeson physics from simulations using four flavors of dynamical quarks with the\nhighly improved staggered quark (HISQ) action. These simulations include\nlattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above\nand at their physical value. The major results are charm meson decay constants\nf_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus\non our procedures for finding the decay constants on each ensemble, the\ncontinuum extrapolation, and estimates of systematic error."
    },
    {
        "anchor": "Parton Physics on a Quantum Computer: Parton distribution functions and hadronic tensors may be computed on a\nuniversal quantum computer without many of the complexities that apply to\nEuclidean lattice calculations. We detail algorithms for computing parton\ndistribution functions and the hadronic tensor in the Thirring model. Their\ngeneralization to QCD is discussed, with the conclusion that the parton\ndistribution function is best obtained by fitting the hadronic tensor, rather\nthan direct calculation. As a side effect of this method, we find that\nlepton-hadron cross sections may be computed relatively cheaply. Finally, we\nestimate the computational cost of performing such a calculation on a digital\nquantum computer, including the cost of state preparation, for physically\nrelevant parameters.",
        "positive": "Exact Vacuum Energy of Orbifold Lattice Theories: We investigate the orbifold lattice theories constructed from supersymmetric\nYang-Mills matrix theories (mother theories) with four and eight supercharges.\nWe show that the vacuum energy of these theories does not receive any quantum\ncorrection perturbatively."
    },
    {
        "anchor": "Testing improved actions for dynamical Kogut-Susskind quarks: We extend tests of \"Naik\" and \"fat link\" improvements of the Kogut-Susskind\nquark action to full QCD simulations, and verify that the improvements\npreviously demonstrated in the quenched approximation apply also to dynamical\nquark simulations. We extend the study of flavor symmetry improvement to the\ncomplete set of pions, and find that the nonlocal pions are significantly\nheavier than the local non-Goldstone pion. These results can be used to\nestimate the lattice spacing necessary for realistic simulations with this\naction.",
        "positive": "The strange quark content of the nucleon in 2+1 flavor lattice QCD: The strangeness of the nucleon, <N|ss|N> - <0|ss|0>, is a quantity of\ninterest for interpreting the results of dark matter detection experiments as\nwell as for exploring the structure of the nucleon itself. We present a\ncalculation of this quantity in 2+1 flavor lattice QCD using a range of lattice\nspacings and quark masses. The method is based on calculating quark-line\ndisconnected contributions on the MILC lattice configurations, which include\nthe effects of dynamical strange quarks. After continuum and chiral\nextrapolations, the value is <N|ss|N> - <0|ss|0> = 0.69 +/- 0.07(stat) +/-\n0.09(sys) in the msbar(2GeV) regularization."
    },
    {
        "anchor": "Quark mass determinations with the RI-SMOM scheme and HISQ action: Lattice QCD provides several avenues for the high precision determination of\nquark masses. Using the RI-SMOM scheme applied to lattice calculations with the\nHISQ action, we obtain mass renormalisation factors that we use to provide\nstrange and charm quark masses with 1% precision. The calculation involves the\nstudy of various sources of systematic uncertainty, including an analysis of\npossible nonperturbative (condensate) contributions. These results allow a\ncomparison of different mass determination methods of comparable precision. In\nparticular we (HPQCD) find good agreement between RI-SMOM and current-current\ncorrelator determinations based on the same lattice QCD bare masses, providing\na strong test of our understanding of systematic uncertainties.",
        "positive": "SU(3) lattice gauge theory with a mixed fundamental and adjoint\n  plaquette action: Lattice artefacts: We study the four-dimensional SU(3) gauge model with a fundamental and an\nadjoint plaquette term in the action. We investigate whether corrections to\nscaling can be reduced by using a negative value of the adjoint coupling. To\nthis end, we have studied the finite temperature phase transition, the static\npotential and the mass of the 0^{++} glueball. In order to compute these\nquantities we have implemented variance reduced estimators that have been\nproposed recently. Corrections to scaling are analysed in dimensionless\ncombinations such as T_c/\\sqrt{\\sigma} and m_{0^{++}}/T_c. We find that indeed\nthe lattice artefacts in e.g. m_{0^{++}}/T_c can be reduced considerably\ncompared with the pure Wilson (fundamental) gauge action at the same lattice\nspacing."
    },
    {
        "anchor": "Finite size and temperature effects in the AF Heisenberg model: The low temperature and large volume effects in the d=2+1 antiferromagnetic\nquantum Heisenberg model are dominated by magnon excitations. The leading and\nnext-to-leading corrections are fully controlled by three physical constants,\nthe spin stiffness, the spin wave velocity and the staggered magnetization.\nAmong others, the free energy, the ground state energy, the low lying\nexcitations, staggered magnetization, staggered and uniform susceptibilities\nare studied here. The special limits of very low temperature and infinite\nvolume are considered also.",
        "positive": "QCD at High Temperature : Results from Lattice Simulations with an\n  Imaginary mu: We summarize our results on the phase diagram of QCD with emphasis on the\nhigh temperature regime. For $T \\ge 1.5 T_c$ the results are compatible with a\nfree field behavior, while for $T \\simeq 1.1 T_c$ this is not the case, clearly\nexposing the strongly interacting nature of QCD in this region"
    },
    {
        "anchor": "Hadron Masses From Novel Fat-Link Fermion Actions: The hadron mass spectrum is calculated in lattice QCD using a novel fat-link\nclover fermion action in which only the irrelevant operators in the fermion\naction are constructed using smeared links. The simulations are performed on a\n16^3 x 32 lattice with a lattice spacing of a=0.125 fm. We compare actions with\nn=4 and 12 smearing sweeps with a smearing fraction of 0.7. The n=4 Fat-Link\nIrrelevant Clover (FLIC) action provides scaling which is superior to\nmean-field improvement, and offers advantages over nonperturbative 0(a)\nimprovement, including a reduced exceptional configuration problem.",
        "positive": "Nonzero chemical potential in the overlap Dirac operator and comparison\n  to random matrix theory: In this talk we present the results published recently in Ref. [1], where we\nshowed how to introduce a quark chemical potential in the overlap Dirac\noperator. The resulting operator satisfies a Ginsparg-Wilson relation and has\nexact zero modes. It is no longer gamma_5-Hermitian, but its nonreal\neigenvalues still occur in pairs. We compute the spectral density of the\noperator on the lattice and show that, for small eigenvalues, the data agree\nwith analytical predictions of non-Hermitian chiral random matrix theory for\nboth trivial and nontrivial topology. We also explain an observed change in the\nnumber of zero modes as a function of chemical potential."
    },
    {
        "anchor": "Temporal Correlators in the Continuous Time Formulation of Strong\n  Coupling Lattice QCD: We present results for lattice QCD in the limit of infinite gauge coupling on\na discrete spatial but continuous Euclidean time lattice. A worm type Monte\nCarlo algorithm is applied in order to sample two-point functions which gives\naccess to the measurement of mesonic temporal correlators. The continuous time\nlimit, based on sending $N_\\tau\\rightarrow \\infty$ and the bare anistotropy to\ninfinity while fixing the temperature in a non-perturbative setup, has various\nadvantages: the algorithm is sign problem free, fast, and accumulates high\nstatistics for correlation functions. Even though the measurement of temporal\ncorrelators requires the introduction of a binning in time direction, this\ndiscretization can be chosen to be by orders finer compared to discrete\ncomputations. For different spatial volumes, temporal correlators are measured\nat zero spatial momentum for a variety of mesonic operators. They are fitted to\nextract the pole masses and corresponding particles as a function of the\ntemperature. We conclude discussing the possibility to extract transport\ncoefficients from these correlators.",
        "positive": "Efficient Modelling of Trivializing Maps for Lattice $\u03c6^4$ Theory\n  Using Normalizing Flows: A First Look at Scalability: General-purpose Markov Chain Monte Carlo sampling algorithms suffer from a\ndramatic reduction in efficiency as the system being studied is driven towards\na critical point. Recently, a series of seminal studies suggested that\nnormalizing flows - a class of deep generative models - can form the basis of a\nsampling strategy that does not suffer from this 'critical slowing down'. The\ncentral idea is to use machine learning techniques to build (approximate)\ntrivializing maps, i.e. field transformations that map the theory of interest\ninto a 'simpler' theory in which the degrees of freedom decouple, and where the\nstatistical weight in the path integral is given by a distribution from which\nsampling is easy. No separate process is required to generate training data for\nsuch models, and convergence to the desired distribution is guaranteed through\na reweighting procedure such as a Metropolis test. In a proof-of-principle\ndemonstration on two-dimensional $\\phi^4$ theory, Albergo et al.\n(arXiv:1904.12072) modelled the trivializing map as a sequence of pointwise\naffine transformations. We pick up this thread, with the aim of quantifying how\nwell we can expect this approach to scale as we increase the number of degrees\nof freedom in the system. We make several modifications to the original design\nthat allow our models learn more efficient representations of trivializing maps\nusing much smaller neural networks, which leads to a large reduction in the\ncomputational cost required to train models of equivalent quality. After making\nthese changes, we find that sampling efficiency is almost entirely dictated by\nhow extensively a model has been trained, while being unresponsive to further\nalterations that increase model flexibility. However, as we move towards the\ncontinuum limit the training costs scale extremely quickly, which urgently\nrequires further work to fully understand and mitigate."
    },
    {
        "anchor": "Spectroscopy of doubly and triply-charmed baryons from lattice QCD: We present the ground and excited state spectra of doubly and triply-charmed\nbaryons by using lattice QCD with dynamical clover fermions. A large set of\nbaryonic operators that respect the symmetries of the lattice and are obtained\nafter subduction from their continuum analogues are utilized. Using novel\ncomputational techniques correlation functions of these operators are generated\nand the variational method is exploited to extract excited states. The lattice\nspectra that we obtain have baryonic states with well-defined total spins up to\n7/2 and the low lying states remarkably resemble the expectations of quantum\nnumbers from SU(6) $\\otimes$ O(3) symmetry. Various energy splittings between\nthe extracted states, including splittings due to hyperfine as well as\nspin-orbit coupling, are considered and those are also compared against similar\nenergy splittings at other quark masses. Using those splittings for\ndoubly-charmed baryons, and taking input of experimental $B_c$ meson mass, we\npredict the mass splittings of $B^*_c - B_c$ to be about 80 $\\pm$ 8 MeV and\n$m_{\\Omega_{ccb}} = 8050\\pm10$ MeV.",
        "positive": "Remarks on the construction of worm algorithms for lattice field\n  theories in worldline representation: We introduce a generalized worldline model where the partition function is a\nsum over configurations of a conserved flux on a d-dimensional lattice. The\nweights for the configurations of the corresponding worldlines have factors\nliving on the links of the lattice, as well as terms which live on the sites x\nand depend on all fluxes attached to x. The model represents a general class of\nworldline systems, among them the dual representation of the relativistic Bose\ngas at finite density. We construct a suitable worm algorithm and show how to\ncorrectly distribute the site weights in the various Metropolis probabilities\nthat determine the worm. We analyze the algorithm in detail and give a proof of\ndetailed balance. Our algorithm admits the introduction of an amplitude\nparameter A that can be chosen freely. Using a numerical simulation of the\nrelativistic Bose gas we demonstrate that A allows one to influence the\nstarting and terminating probabilities and thus the average length and the\nefficiency of the worm."
    },
    {
        "anchor": "Radiative corrections to the m(oving)NRQCD action and heavy-light\n  operators: Rare decays of B mesons, such as B \\to K^*\\gamma and B\\to K^{(*)}\\ell^+\\ell^-\nare loop suppressed in the Standard Model and sensitive to new physics. The\nfinal state meson in heavy-light decays at large recoil has sizeable momentum\nin the rest frame of the decaying meson. To reduce the resulting discretization\nerrors we formulate the nonrelativistic heavy quark action in a moving frame.\nWe discuss the perturbative renormalization of the leading order heavy-light\noperators in the resulting theory which is known as m(oving)NRQCD.\n  We also present radiative corrections to the NRQCD action computed using\nautomated lattice perturbation theory. By combining this technique with\nhigh-beta simulations in the weak coupling regime of the theory higher order\nloop corrections can be calculated very efficiently.",
        "positive": "Vector and axial-vector couplings of D and D* mesons in 2+1 flavor\n  Lattice QCD: Using the axial-vector coupling and the electromagnetic form factors of the D\nand D* mesons in 2+1 flavor Lattice QCD, we compute the D*D\\pi, DD\\rho and\nD*D*\\rho coupling constants, which play an important role in describing the\ncharm hadron interactions in terms of meson-exchange models. We also extract\nthe charge radii of D and D* mesons and determine the contributions of the\nlight and charm quarks separately."
    },
    {
        "anchor": "Corrections to the hadron resonance gas from lattice QCD and their\n  effect on fluctuation-ratios at finite density: The hadron resonance gas (HRG) model is often believed to correctly describe\nthe confined phase of QCD. This assumption is the basis of many\nphenomenological works on QCD thermodynamics and of the analysis of hadron\nyields in relativistic heavy ion collisions. We use first-principle lattice\nsimulations to calculate corrections to the ideal HRG. Namely, we determine the\nsub-leading fugacity expansion coefficients of the grand canonical free energy,\nreceiving contributions from processes like kaon-kaon or baryon-baryon\nscattering. We achieve this goal by performing a two dimensional scan on the\nimaginary baryon number chemical potential ($\\mu_B$) - strangeness chemical\npotential ($\\mu_S$) plane, where the fugacity expansion coefficients become\nFourier coefficients. We carry out a continuum limit estimation of these\ncoefficients by performing lattice simulations with temporal extents of\n$N_\\tau=8,10,12$ using the 4stout-improved staggered action. We then use the\ntruncated fugacity expansion to extrapolate ratios of baryon number and\nstrangeness fluctuations and correlations to finite chemical potentials.\nEvaluating the fugacity expansion along the crossover line, we reproduce the\ntrend seen in the experimental data on net-proton fluctuations by the STAR\ncollaboration.",
        "positive": "Calculation of $K \\to \u03c0\u03c0$ decay amplitudes with improved Wilson\n  fermion: We present results of our trial calculation of the $K \\to \\pi\\pi$ decay\namplitudes with the improved Wilson fermion action. Calculations are carried\nout with $N_f=2+1$ gauge configurations generated with the Iwasaki gauge action\nand non-perturbatively $O(a)$-improved Wilson fermion action at $a=0.091\\,{\\rm\nfm}$, $m_\\pi=280\\,{\\rm MeV}$ and $m_K=560\\,{\\rm MeV} (\\sim 2 m_\\pi)$ on a\n$32^3\\times 64$ ($La=2.9 {\\rm fm}$) lattice."
    },
    {
        "anchor": "Screening Masses in SU(2) Pure Gauge Theory: We perform a systematic scaling study of screening masses in pure gauge SU(2)\ntheory at temperatures above the phase transition temperature. The major finite\nvolume effect is seen to be spatial deconfinement. We extract the screening\nmasses in the infinite volume and zero lattice spacing limit. We find that\nthese physical results can be deduced from runs on rather coarse lattices.\nDimensional reduction is clearly seen in the spectrum.",
        "positive": "Numerical Study of the Chiral Separation Effect in Two-Color QCD at\n  Finite Density: We study the Chiral Separation Effect (CSE) in finite-density SU(2) lattice\ngauge theory with dynamical quarks. We find that the CSE is well described by\nthe free quark result in the high-temperature quark-gluon plasma phase. As one\nenters the confinement regime with broken chiral symmetry at chemical potential\nsmaller than half of the pion mass, the CSE response is gradually suppressed\ntowards low temperatures in comparison to the free quark result. This\nsuppression can be approximately described by assuming that the CSE current is\nproportional to the charge density, rather than the chemical potential, as\nsuggested in the literature (ArXiv:1712.01256, Phys.Rev.D97(2018)085020). We\nalso provide an upper bound on the contribution of disconnected fermionic\ndiagrams to the CSE, which is consistent with zero within our statistical\nerrors and small compared to that of the connected diagrams. Our results are\nobtained mainly in the QCD-like regime of SU(2) gauge theory at low densities,\nand hence should be at least qualitatively applicable to QCD as well."
    },
    {
        "anchor": "One loop renormalization for the axial Ward-Takahashi identity in\n  Domain-wall QCD: We calculate one-loop correction to the axial Ward-Takahashi identity given\nby Furman and Shamir in domain-wall QCD. It is shown perturbatively that the\nrenormalized axial Ward-Takahashi identity is satisfied without fine tuning and\nthe ``conserved'' axial current receives no renormalization, giving $Z_A=1$.\nThis fact will simplify the calculation of the pion decay constant in numerical\nsimulations since the decay constant defined by this current needs no lattice\nrenormalization factor.",
        "positive": "Before sailing on a domain-wall sea: We discuss the very different roles of the valence-quark and the sea-quark\nresidual masses ($m_{res}^v$ and $m_{res}^s$) in dynamical domain-wall fermions\nsimulations. Focusing on matrix elements of the effective weak hamiltonian\ncontaining a power divergence, we find that $m_{res}^v$ can be a source of a\nmuch bigger systematic error. To keep all systematic errors due to residual\nmasses at the 1% level, we estimate that one needs $a m_{res}^s \\le 10^{-3}$\nand $a m_{res}^v \\le 10^{-5}$, at a lattice spacing $a\\sim 0.1$ fm. The\npractical implications are that (1) optimal use of computer resources calls for\na mixed scheme with different domain-wall fermion actions for the valence and\nsea quarks; (2) better domain-wall fermion actions are needed for both the sea\nand the valence sectors."
    },
    {
        "anchor": "The pion mass in finite volume to two loops: We evaluate the pion mass in finite volume to two loops within Chiral\nPerturbation Theory. The results are compared with a recently proposed\nextension of the asymptotic formula of Luscher. We find that contributions,\nwhich were neglected in the latter, are numerically very small at the two-loop\nlevel.",
        "positive": "The gradient flow coupling at high-energy and the scale of SU(3)\n  Yang-Mills theory: Using finite size scaling techniques and a renormalization scheme based on\nthe Gradient Flow, we determine non-perturbatively the $\\beta$-function of the\n$SU(3)$ Yang-Mills theory for a range of renormalized couplings $\\bar g^2\\sim\n1-12$. We perform a detailed study of the matching with the asymptotic NNLO\nperturbative behavior at high-energy, with our non-perturbative data showing a\nsignificant deviation from the perturbative prediction down to\n$\\bar{g}^2\\sim1$. We conclude that schemes based on the Gradient Flow are not\ncompetitive to match with the asymptotic perturbative behavior, even when the\nNNLO expansion of the $\\beta$-function is known. On the other hand, we show\nthat matching non-perturbatively the Gradient Flow to the Schr\\\"odinger\nFunctional scheme allows us to make safe contact with perturbation theory with\nfull control on truncation errors. This strategy allows us to obtain a precise\ndetermination of the $\\Lambda$-parameter of the $SU(3)$ Yang-Mills theory in\nunits of a reference hadronic scale ($\\sqrt{8t_0}\\,\\Lambda_{\\overline{\\rm MS}}\n= 0.6227(98)$), showing that a precision on the QCD coupling below 0.5\\%\nper-cent can be achieved using these techniques."
    },
    {
        "anchor": "Monte Carlo evaluation of a fermion number violating observable in 2D: We describe in some detail a computer evaluation of a 't Hooft vertex in a\ntwo dimensional model using the overlap. The computer result agrees with the\nknown exact continuum value, and in this sense our work is a first successful\nfully dynamical simulation of a chiral gauge theory on the lattice. We add some\nnew data to numbers obtained earlier and provide a selfcontained description\nwhich should make it easy for others to reproduce and follow up on our work.",
        "positive": "The hermitian Wilson-Dirac operator in smooth SU(2) instanton\n  backgrounds: We study the spectral flow of the hermitian Wilson-Dirac operator $\\ham(m)$\nas a function of $m$ in smooth SU(2) instanton backgrounds on the lattice. For\na single instanton background with Dirichlet boundary conditions on $\\ham(m)$,\nwe find a level crossing in the spectral flow of $\\ham(m)$, and we find the\nshape of the crossing mode at the crossing point to be in good agreement with\nthe zero mode associated with the single instanton background. With\nanti-periodic boundary conditions on $\\ham(m)$, we find that the instanton\nbackground in the singular gauge has the correct spectral flow but the one in\nregular gauge does not. We also investigate the spectral flows of two instanton\nand instanton-anti-instanton backgrounds."
    },
    {
        "anchor": "Lattice representation of vector and chiral gauge theories: A lattice derivative is defined as a discrete Fourier transform of momentum\non a finite lattice. Species doublers are removed with anti-periodic boundary\nconditions. U(1) chiral transformation is modified to reproduce chiral anomaly.\nChiral gauge theories can be constructed on the lattice using a single Weyl\nfermion as a building block.",
        "positive": "Large-time correlation functions in bosonic lattice field theories: Large-time correlation functions have a pivotal role in extracting particle\nmasses from Euclidean lattice field theory calculations, however little is\nknown about the statistical properties of these quantities. In this work, the\nasymptotic form of the distributions of the correlation functions at vanishing\nmomentum is determined for bosonic interacting lattice field theories with a\nunique gapped vacuum. It is demonstrated that the deviations from the\nasymptotic form at large Euclidean times can be utilized to determine the\nspectrum of the theory."
    },
    {
        "anchor": "$B_c$ spectroscopy using highly improved staggered quarks: We report on a calculation of $B_c$ ground state and radial excitation\nenergies, obtained from heavy-charm highly improved staggered quark (HISQ)\ncorrelators computed on MILC gauge ensembles, with lattice spacings down to\n$a=0.044$ fm. Using HISQ valence quarks on progressively finer lattices allows\nus to simulate up to the $b$-quark mass. In particular we focus on the\n$B_c(2S)$ energy, which we compare with O(\\alpha_s)-improved non-relativistic\nQCD results computed on the same ensembles and recent experimental results from\nATLAS.",
        "positive": "The thermal QCD transition with two flavours of twisted mass fermions: We investigate the thermal QCD transition with two flavors of maximally\ntwisted mass fermions for a set of pion masses, 300 MeV \\textless $m_\\pi$\n\\textless 500 MeV, and lattice spacings $a$ \\textless 0.09 fm. We determine the\npseudo-critical temperatures and discuss their extrapolation to the chiral\nlimit using scaling forms for different universality classes, as well as the\nscaling form for the magnetic equation of state. For all pion masses considered\nwe find resonable consistency with O(4) scaling plus leading corrections.\nHowever, a true distinction between the O(4) scenario and a first order\nscenario in the chiral limit requires lighter pions than are currently in use\nin simulations of Wilson fermions."
    },
    {
        "anchor": "Corrections to finite-size scaling in two-dimensional O(N) sigma-models: We have considered the corrections to the finite-size-scaling functions for a\ngeneral class of $O(N)$ $\\sigma$-models with two-spin interactions in two\ndimensions for $N=\\infty$. We have computed the leading corrections finding\nthat they generically behave as $(f(z) \\log L + g(z))/L^2$ where $z = m(L) L$\nand $m(L)$ is a mass scale; $f(z)$ vanishes for Symanzik improved actions for\nwhich the inverse propagator behaves as $q^2 + O(q^6)$ for small $q$, but not\nfor on-shell improved ones. We also discuss a model with four-spin interactions\nwhich shows a much more complicated behaviour.",
        "positive": "Noise Methods for Flavor Singlet Quantities: A discussion of methods for reducing the noise variance of flavor singlet\nquantities (\"disconnected diagrams\") in lattice QCD is given. After an\nintroduction, the possible advantage of partitioning the Wilson fermion matrix\ninto disjoint spaces is discussed and a numerical comparison of the variance\nfor three possible partitioning schemes is carried out. The measurement\nefficiency of lattice operators is examined and shown to be strongly influenced\nby the Dirac and color partitioning choices. Next, the numerical effects of an\nautomated subtraction algorithm on the noise variance of various disconnected\nloop matrix elements are examined. It is found that there is a dramatic\nreduction in the variance of the Wilson point-split electromagnetic currents\nand that this reduction persists at small quark mass."
    },
    {
        "anchor": "Anomalous Fermion Number Non-Conservation on the Lattice: The anomaly for the fermion number current is calculated on the lattice in a\nsimple prototype model with an even number of fermion doublets.",
        "positive": "Vortex configurations in SO(3) \\times Z(2): We study the configuration space of the Tomboulis $SO(3) \\times Z(2)$\nformulation with periodic boundary conditions. The dynamical variables are\nconstrained by the required coincidence of Z(2) and SO(3) monopoles.\nFurthermore, there is an additional constraint coming from the boundary\nconditions. We propose an update algorithm that satisfies the constraints and\nis straightforward to implement."
    },
    {
        "anchor": "Finite Temperature QCD with Domain Wall Fermions: Domain wall fermions are a new lattice fermion formulation which preserves\nthe full chiral symmetry of the continuum at finite lattice spacing, up to\nterms exponentially small in an extra parameter. We discuss the main features\nof the formulation and its application to study of QCD with two light fermions\nof equal mass. We also present numerical studies of the two flavor QCD\nthermodynamics with aT = 1/4.",
        "positive": "Perturbative Renormalization of Lattice Bilinear Quark Operators: Our aim is to compute the lower moments of the unpolarized and polarized\ndeep-inelastic structure functions of the nucleon on the lattice. The\ntheoretical basis of the calculation is the operator product expansion. To\nconstruct operators with the appropriate continuum behavior out of the bare\nlattice operators one must absorb the effects of momentum scales far greater\nthan any physical scale into a renormalization of the operators. In this work\nwe compute the renormalization constants of all bilinear quark operators of\nleading twist and spin up to four. The calculation is done for Wilson fermions\nand in the quenched approximation where dynamical quark loops are neglected."
    },
    {
        "anchor": "Static forces in d=2+1 SU(N) gauge theories: Using a three-level algorithm we perform a high-precision lattice computation\nof the static force up to 1fm in the 2+1 dimensional SU(5) gauge theory.\nDiscretization errors and the continuum limit are discussed in detail. By\ncomparison with existing SU(2) and SU(3) data it is found that \\sigma\nr_0^2=1.65-\\pi/24 holds at an accuracy of 1% for all N>=2, where r_0 is the\nSommer reference scale. The effective central charge c_{eff}(r) is obtained and\nan intermediate distance r_s is defined via the property c_{eff}(r_s)=\\pi/24.\nIt separates in a natural way the short-distance regime governed by\nperturbation theory from the long-distance regime described by an effective\nstring theory. The ratio r_s/r_0 decreases significantly from SU(2) to SU(3) to\nSU(5), where r_s < r_0. We give a preliminary estimate of its value in the\nlarge-N limit. The static force in the smallest representation of N-ality 2,\nwhich tends to the k=2 string tension as r->oo, is also computed up to 0.7fm.\nThe deviation from Casimir scaling is positive and grows from 0.1% to 1% in\nthat range.",
        "positive": "Lattice QCD with mixed actions: We discuss some of the implications of simulating QCD when the action used\nfor the sea quarks is different from that used for the valence quarks. We\npresent exploratory results for the hadron mass spectrum and pseudoscalar meson\ndecay constants using improved staggered sea quarks and HYP-smeared overlap\nvalence quarks. We propose a method for matching the valence quark mass to the\nsea quark mass and demonstrate it on UKQCD clover data in the simpler case\nwhere the sea and valence actions are the same."
    },
    {
        "anchor": "In search of a scaling scalar glueball: Anisotropic lattices are an efficient means of studying the glueballs of QCD,\nhowever problems arise with simulations of the lightest, scalar state. The mass\nis strongly dependent on the lattice spacing, even when a mean-field improved\ngluon action is used. The nature and cause of these errors are discussed and\nthe scaling properties of the scalar from different lattice actions are\npresented.",
        "positive": "Gluons in charmoniumlike states: The mass components of charmoniumlike states are investigated through the\ndecomposition of QCD energy-momentum tensor (EMT) on lattice. The quark mass\ncontribution $\\langle H_m\\rangle$ and the momentum fraction $\\langle x\\rangle$\nof valence charm quark and antiquark are calculated for conventional $1S,1P,1D$\ncharmonia and the exotic $1^{-+}$ charmoniumlike state, based on the $N_f=2+1$\ngauge configurations generated by the RBC/UKQCD collaboration. It is found that\n$\\langle H_m\\rangle$ is close to each other and around 2.0 to 2.2 GeV for these\nstates, which implies that the mass splittings among these states come almost\nfrom the gluon contribution of QCD trace anomaly. The $\\langle x\\rangle$ of the\n$1^{-+}$ state is only around 0.55, while that in conventional charmonia is\naround 0.7 to 0.8. This difference manifests that the proportion of light\nquarks and gluons in the $1^{-+}$ charmoniumlike state is significantly larger\nthan conventional states."
    },
    {
        "anchor": "A novel scheme for the wave function renormalization of the composite\n  operators: We propose a novel renormalization scheme for the hadronic operators. The\nrenormalization factor of the operator in this scheme is normalized by the\ncorrelation function at tree level in coordinate space. If we focus on the\npseudo scalar operator, then its renormalization factor is related to the mass\nrenormalization factor of the fermion through the partially conserved\naxial-vector current (PCAC) relation. Using the renormalization factor for the\npseudo scalar operator in our scheme, we obtain the mass anomalous dimension of\nthe SU(3) gauge theory coupled to N_f=12 massless fundamental fermions, which\nhas an infrared fixed point (IRFP). The mass anomalous dimension at the IRFP is\nestimated as gamma_m^*= 0.044_{-0.024}^{+0.025} (stat.)_{-0.032}^{+0.057}\n(syst.).",
        "positive": "Short distance current correlators: Comparing lattice simulations to the\n  instanton liquid: Point to point correlators of currents are computed in quenched QCD using a\nchiral lattice fermion action, the overlap action. I compare correlators made\nof exact quark propagators with correlators restricted to low (less than 500\nMeV) eigenvalue eigenmodes of the Dirac operator. In many cases they show\nqualitative resemblence (typically at small values of the quark mass and\ndistances larger than 0.4 fm) and they differ qualitatively at larger quark\nmasses or at very short distance. Lattice results are in qualitative agreement\n(and in the difference of vector and axial vector channels, quantitative\nagreement) with the expectations of instanton liquid models. The scalar channel\nshows the effects of a quenched finite volume zero mode artifact, a negative\ncorrelator."
    },
    {
        "anchor": "The Static Approximation to B Meson Mixing using Light Domain-Wall\n  Fermions: Perturbative Renormalization and Ground State Degeneracies: We discuss the theoretical input into the current RBC-UKQCD calculation of\n$f_{B_{d, s}}$ and $B_{B_{d, s}}$ using a smeared static heavy quark\npropagator, light domain-wall quarks and the Iwasaki gauge action. We present\nthe complete one-loop, mean-field improved matching of heavy-light current and\nfour-fermion lattice operators onto the static continuum theory renormalized in\n$\\bar{\\text{MS}}$(NDR). The large degeneracies present in a static calculation\nare addressed, and a method for extracting $f_B$ and $B_B$ using only box\nsources is described; implications for future calculations are discussed.",
        "positive": "Monopoles, confinement and the photon propagator in QED$_3$: We study the lattice gauge boson propagator of 3D compact QED in Landau gauge\nat zero and non-zero temperature. Non-perturbative effects are reflected by the\ngeneration of a mass $m$, by an anomalous dimension $\\alpha$ and by the photon\nwave function renormalisation $Z$. These effects can be attributed to\nmonopoles: they are absent in the propagator of the regular part of the gauge\nfield. The r\\^ole of Gribov copies is carefully investigated."
    },
    {
        "anchor": "Compact QED: the photon propagator, confinement and positivity violation\n  for the pure gauge theory: The lattice Landau gauge photon propagator for the pure gauge theory is\nrevisited using large lattices. For the confined case we show that it has an\nassociated linearly growing potential, it has a mass gap, that is related to\nthe presence of monopoles, and its spectral function violates positivity. In\nthe deconfined phase, our simulations suggest that a free field theory is\nrecovered in the thermodynamic limit.",
        "positive": "Results and Perspectives in HEP, vis-a-vis Lattice QCD: I review in this presentation some aspects of phenomenology in High Energy\nPhysics which are related to recent and possibly future progress in lattice\nQCD. In particular, I cover (i) the extraction of CKM matrix elements from B\nphysics, (ii) the determination of epsilon'/epsilon, as well as (iii) some\nissues emerged in the physics of high energy jets produced in hadronic\ncollisions, where input from non-perturbative calculations would benefit our\ncapability to perform better theoretical predictions."
    },
    {
        "anchor": "On the analytic continuation of the critical line: We perform a numerical study of the systematic effects involved in the\ndetermination of the critical line at real baryon chemical potential by\nanalytic continuation from results obtained at imaginary chemical potentials.\nWe present results obtained in a theory free of the sign problem, three-color\nQCD with finite isospin chemical potential, and comment on general features\nwhich could be relevant also to the continuation of the critical line in real\nQCD at finite baryon density.",
        "positive": "Sign optimization and complex saddle points in one-dimensional QCD: We study one-dimensional QCD at finite quark density by using the sign\noptimization framework. The fermion sign problem is mitigated by deforming the\npath integral domain, $SU(3)$ to a complexified one ${\\cal M} \\subset SL(3)$,\nexplicitly constructed to reduce the phase fluctuations. The complexification\nis constructed using the angular representation of $SU(3)$. We provide a\nphysical explanation of the optimization procedure in terms of complex saddle\npoints. This picture connects the sign optimization framework to the\ngeneralized Lefschetz thimbles."
    },
    {
        "anchor": "Recent Results of Multimagnetical Simulations of the Ising Model: To investigate order-order interfaces, we perform multimagnetical Monte Carlo\nsimulations of the $2D$ and $3D$ Ising model. Stringent tests of the numerical\nmethods are performed by reproducing with high precision exact $2D$ results. In\nthe physically more interesting $3D$ case we estimate the amplitude $F^s_0$ of\nthe critical interfacial tension.",
        "positive": "Heavy meson chiral perturbation theory in finite volume: We study finite volume effects in heavy quark systems in the framework of\nheavy meson chiral perturbation theory for full, quenched, and partially\nquenched QCD. A novel feature of this investigation is the role played by the\nscales Delta and delta_s, where Delta is the mass difference between the\nheavy-light vector and pseudoscalar mesons of the same quark content, and\ndelta_s is the mass difference due to light flavour SU(3) breaking. The primary\nconclusion of this work is that finite volume effects arising from the\npropagation of Goldstone particles in the effective theory can be altered by\nthe presence of these scales. Since Delta varies significantly with the heavy\nquark mass, these volume effects can be amplified in both heavy and light quark\nmass extrapolations (interpolations). As an explicit example, we present\nresults for B parameters of neutral B meson mixing matrix elements and\nheavy-light decay constants to one-loop order in finite volume heavy meson\nchiral perturbation theory for full, quenched, and N_f=2+1 partially quenched\nQCD. Our calculation shows that for high-precision determinations of the\nphenomenologically interesting SU(3) breaking ratios, finite volume effects are\nsignificant in quenched and not negligible in partially quenched QCD, although\nthey are generally small in full QCD."
    },
    {
        "anchor": "Gluelump masses and mass splittings from SU(3) lattice gauge theory: We compute gluelump masses and mass differences using SU(3) lattice gauge\ntheory. We study states with total angular momentum up to $J = 3$, parity $P =\n+,-$ and charge conjugation $C = +,-$. Computations on four ensembles with\nrather fine lattice spacings in the range $0.040 \\, \\text{fm} \\ldots 0.093 \\,\n\\text{fm}$ allow continuum extrapolations of gluelump mass differences. We\ncomplement existing results on hybrid static potentials with the obtained\ngluelump masses, which represent the limit of vanishing quark-antiquark\nseparation. We also discuss the conversion of lattice gluelump masses to the\nRenormalon Subtracted scheme, which is e.g. important for studies of heavy\nhybrid mesons in the Born-Oppenheimer approximation.",
        "positive": "The QCD phase diagram for external magnetic fields: The effect of an external (electro)magnetic field on the finite temperature\ntransition of QCD is studied. We generate configurations at various values of\nthe quantized magnetic flux with $N_f=2+1$ flavors of stout smeared staggered\nquarks, with physical masses. Thermodynamic observables including the chiral\ncondensate and susceptibility, and the strange quark number susceptibility are\nmeasured as functions of the field strength. We perform the renormalization of\nthe studied observables and extrapolate the results to the continuum limit\nusing $N_t=6,8$ and 10 lattices. We also check for finite volume effects using\nvarious lattice volumes. We find from all of our observables that the\ntransition temperature $T_c$ significantly decreases with increasing magnetic\nfield. This is in conflict with various model calculations that predict an\nincreasing $T_c(B)$. From a finite volume scaling analysis we find that the\nanalytic crossover that is present at B=0 persists up to our largest magnetic\nfields $eB \\approx 1 \\textmd{GeV}^2$, and that the transition strength\nincreases mildly up to this $eB\\approx1 \\textmd{GeV}^2$."
    },
    {
        "anchor": "$\u039b_c\u03a3_c\u03c0$ coupling and $\u03a3_c \\rightarrow\u039b_c \u03c0$\n  decay in lattice QCD: We evaluate the $\\Lambda_c\\Sigma_c\\pi$ coupling constant ($G_{\\Lambda_c\n\\Sigma_c \\pi}$) and the width of the strong decay $\\Sigma_c\n\\rightarrow\\Lambda_c \\pi$ in 2+1 flavor lattice QCD on four different ensembles\nwith pion masses ranging from 700 MeV to 300 MeV. We find $G_{\\Lambda_c\n\\Sigma_c \\pi}=18.332(1.476)_{\\rm{stat.}}(2.171)_{\\rm{syst.}}$ and the decay\nwidth $\\Gamma(\\Sigma_c \\rightarrow\\Lambda_c\n\\pi)=1.65(28)_{\\rm{stat.}}(30)_{\\rm{syst.}}$~MeV on the physical quark-mass\npoint, which is in agreement with the recent experimental determination.",
        "positive": "Lambda-parameter of lattice QCD with Symanzik improved gluon actions: We compute the ratio Lambda_L/Lambda_MS, where the scale parameter Lambda_L\nis associated with a lattice formulation of QCD. We consider a 3-parameter\nfamily of gluon actions, which are most frequently used for O(a) improvement a`\nla Symanzik. The gluon action is put togeter with standard discretizations for\nfermions (Wilson/clover, overlap), to provide Lambda_L for several possible\ncombinations of fermion and gluon actions. We employ the background field\ntechnique in order to calculate the 1PI 2-point function of the background\nfield; this leads to the coupling constant renormalization function, Z_g, at\n1-loop level.\n  Our results are obtained for an extensive range of values for the Symanzik\ncoefficients."
    },
    {
        "anchor": "Point-Split Lattice Operators for B Decays: The matrix element which determines the B meson decay constant can be\nmeasured on the lattice using an effective field theory for heavy quarks.\nVarious discretizations of the heavy-light bilinears which appear in this and\nother B decay matrix elements are possible. The heavy-light bilinear currently\nused for the determination of the B meson decay constant on the lattice suffers\na substantial one-loop renormalization. In this paper, we compute the one-loop\nrenormalizations of the discretizations in which the heavy and light fields in\nthe bilinear are separated by one lattice spacing, and discuss their\napplication. Readers of this paper may also be interested in our paper on the\napplication of Symanzik's improvement program to heavy-light currents (paper\nnumber 9203221 on hep-ph).",
        "positive": "Results from a Non-Perturbative Renormalization of Lattice Operators: We propose a general renormalization method, which avoids completely the use\nof lattice perturbation theory. We present the results from its numerical\napplications to two-fermion operators on a $16^3 \\times 32$ lattice, at\n$\\beta=6.0$."
    },
    {
        "anchor": "Radiative contribution to the effective potential in a composite Higgs\n  model: The SU(4) gauge theory with two flavors of Dirac fermions in the sextet\nrepresentation shares features of a candidate for a composite Higgs model. The\nanalogue of the Higgs multiplet of the Standard Model lives in the Goldstone\nmanifold resulting from spontaneous breaking of the global symmetry SU(4) to\nSO(4). The Higgs potential arises from interaction with the particles of the\nStandard Model. We have computed the gauge boson contribution to the Higgs\npotential, using valence overlap fermions on a Wilson-clover sea. The\ncalculation is similar to that of the electromagnetic mass splitting of the\npion multiplet in QCD.",
        "positive": "Monopole condensation in the ground state of gauge theories: a disorder\n  parameter: We construct a disorder parameter for dual superconductivity of the ground\nstate of $U(1)$ gauge theory."
    },
    {
        "anchor": "Study of three-flavored heavy dibaryons using lattice QCD: We present results of the first lattice QCD calculation of three-flavored\nheavy dibaryons both in the flavor-symmetric and antisymmetric channels. These\ndibaryons have spin zero, and are constructed using various possible\ncombinations of quark flavors with at least one of them as the charm or the\nbottom quark, i.e., namely, $H_c(cudcud), H_b(budbud), H_{bcs}(bcsbcs)$,\n$H_{csl}(cslcsl), H_{bsl}(bslbsl)$ and $H_{bcl}(bclbcl)$; $l\\in u,d$. We\ncompute the ground state masses of these dibaryons and the calculations are\nperformed on three $N_f=2+1+1$ HISQ gauge ensembles of the MILC collaboration,\nwith lattice spacings $a =$ 0.1207, 0.0888 and 0.0582 fm. A relativistic\noverlap action is employed for the valence light to charm quarks while a\nnon-relativistic-QCD Hamiltonian with improved coefficients is used for the\nbottom quarks. Unlike the doubly heavy tetraquarks, one and two-flavored heavy\ndibaryons, for which lattice QCD calculations have predicted deeply bound\nstrong-interactions-stable states, for these $H_c, H_b, H_{csl},H_{bsl}$\ndibaryons we do not find any such deeply bound state. However, for $H_{bcs}$,\nour results indicate the presence of an energy level $29\\pm 24$ MeV below the\nlowest two-baryon threshold, which could be relevant for its future\nexperimental searches. Moreover, we find that the energy difference between the\nground state of $H_{bcl}$ and its lowest threshold increases when $m_l>m_s$.\nTaken together, our findings indicate the possibility of the existence of the\n$H_{bcs}$ dibaryon while all other physical three-flavored dibaryons are much\ncloser to their thresholds suggesting either they are weakly bound or unbound,\nresolving which requires further detail study. Our results also point that the\nbinding of a dibaryon configuration becomes stronger with the increase of its\nvalence quark masses which suggests an interesting aspect of strong\ninteractions at multiple scales.",
        "positive": "Precision Upsilon Spectroscopy from Nonrelativistic Lattice QCD: The spectrum of the Upsilon system is investigated using the Nonrelativistic\nLattice QCD approach to heavy quarks and ignoring light quark vacuum\npolarization. We find good agreement with experiment for the Upsilon(1S),\nUpsilon(2S), Upsilon(3S) and for the center of mass and fine structure of the\nchi_b states. The lattice calculations predict b-bbar D-states with center of\nmass at (10.20 +/- 0.07 +/- 0.03)GeV. Fitting procedures aimed at extracting\nboth ground and excited state energies are developed. We calculate a\nnonperturbative dispersion mass for the Upsilon(1S) and compare with\ntadpole-improved lattice perturbation theory."
    },
    {
        "anchor": "Chiral Fermions and Anomalies on a Finite Lattice: A recent proposal by Kaplan for a chiral gauge theory on the lattice is\ntested with background gauge fields. The spectrum of the finite lattice\nHamiltonian is calculated and the existence of a chiral fermion is\ndemonstrated. Lattice doublers are found to decouple. The flavor anomalies,\nwhich are in agreement with the continuum anomaly relation, are obeserved on a\nfinite lattice. Non-trivial anomaly cancellation is observed in a chiral gauge\ncurrent.",
        "positive": "Screening Masses in SU(2) Pure Gauge Theory: We perform a systematic scaling study of screening masses in pure gauge SU(2)\ntheory at temperatures above the phase transition temperature. The major finite\nvolume effect is seen to be spatial deconfinement. We extract the screening\nmasses in the infinite volume and zero lattice spacing limit. We find that\nthese physical results can be deduced from runs on rather coarse lattices.\nDimensional reduction is clearly seen in the spectrum."
    },
    {
        "anchor": "Chiral Lattice Fermions From Staggered Fields: We describe a proposal for constructing a lattice theory that we argue may be\ncapable of yielding free Weyl fermions in the continuum limit. The model\nemploys reduced staggered fermions and uses site parity dependent Yukawa\ninteractions of Fidkowski-Kitaev type to gap a subset of the lattice fermions\nwithout breaking symmetries. The possibility for such symmetric mass generation\nis tied to the cancellation of certain discrete anomalies arising in the\ncontinuum limit. The latter place strong constraints on the number of lattice\nfermions -- constraints that are satisfied by this model. We present numerical\nresults for the model in two dimensions which support this sc",
        "positive": "First observation of the hidden-charm pentaquarks on lattice: The s-wave scattering of $\\Sigma_c \\bar{D}$ and $\\Sigma_c \\bar{D}^*$ in the\n$I(J^P) = \\frac{1}{2}(\\frac{1}{2}^-)$ channel is calculated in lattice QCD\nusing two ensembles with different volumes but the same lattice spacing $a\\sim\n0.08\\mathrm{fm}$ and pion mass $M_\\pi \\sim 294\\mathrm{MeV}$. The scattering\namplitudes near threshold are obtained by L\\\"uscher's finite volume method. We\nfind bound state poles in both $\\Sigma_c \\bar{D}$ and $\\Sigma_c \\bar{D}^*$\nchannels, which are possibly related to the $P_c(4312)$ and $P_c(4440) /\nP_c(4457)$ pentaquarks observed in experiments. The binding energy is\n$6(2)(2)$MeV for $\\Sigma_c \\bar{D}$ and $7(3)(1)$MeV for $\\Sigma_c \\bar{D}^*$,\nwhere the first error is the statistical error and the second is the systematic\nerror due to the lattice artifacts."
    },
    {
        "anchor": "Spontaneous CP violation and quark mass ambiguities: I explore the regions of quark masses where CP will be spontaneously broken\nin the strong interactions. The boundaries of these regions are controlled by\nthe chiral anomaly, which manifests itself in ambiguities in the definition of\nnon-degenerate quark masses. In particular, the concept of a single massless\nquark is ill defined.",
        "positive": "A first look at maximally twisted mass lattice QCD calculations at the\n  physical point: In this contribution, a first look at simulations using maximally twisted\nmass Wilson fermions at the physical point is presented. A lattice action\nincluding clover and twisted mass terms is presented and the Monte Carlo\nhistories of one run with two mass-degenerate flavours at a single lattice\nspacing are shown. Measurements from the light and heavy-light pseudoscalar\nsectors are compared to previous $N_f = 2$ results and their phenomenological\nvalues. Finally, the strategy for extending simulations to $N_f = 2 + 1 + 1$ is\noutlined."
    },
    {
        "anchor": "A numerical and theoretical study of multilevel performance for\n  two-point correlator calculations: An investigation of the performance of the multilevel algorithm in the\napproach to criticality has been undertaken using the Ising model, performing\nsimulations across a range of temperatures. Numerical results show that the\nperformance of multilevel in this system deteriorates as the correlation length\nis increased with respect to the lattice size. The statistical error of the\nlongest correlator in the system is reduced in a multilevel setup when the\ncorrelation length is less than one-tenth of the lattice size, while for longer\ncorrelation lengths multilevel performs more poorly than a computer-time\nequivalent single level algorithm. A theoretical model of this performance\nscaling is outlined, and shows remarkable accuracy when compared to numerical\nresults. This theoretical model may be applied to other systems with more\ncomplex spectra to predict if multilevel techniques are likely to result in\nimproved statistics.",
        "positive": "SO(3) versus SU(2) lattice gauge theory: We consider the SO(3) lattice gauge theory at weak coupling, in the Villain\naction. We exhibit an analytic path in coupling space showing the equivalence\nof the SO(3) theory with SU(2) summed over all twist sectors. This clarifies\nthe ``mysterious phase'' of SO(3). As order parameter, we consider the dual\nstring tension or center vortex free energy, which we measure in SO(3) using\nmulticanonical Monte Carlo. This allows us to set the scale, indicating that\n${\\cal O}(700)^4$ lattices are necessary to probe the confined phase. We\nconsider the relevance of our findings for confinement in other gauge groups\nwith trivial center."
    },
    {
        "anchor": "Doubly charmed tetraquark $T_{cc}^+$ in (2+1)-flavor QCD near physical\n  point: We study the doubly charmed tetraquark state $T_{cc}^+$ by the HAL QCD method\napplied to the $D^*D$ system in $(2+1)$ flavor lattice QCD at nearly physical\npion mass, $m_\\pi= 146$ MeV. We obtain the attractive potential at all\ndistances in the $S$-wave of the isoscalar $D^* D$ system, whose long distance\nbehavior is well described by the two-pion exchange (TPE), and it generates a\nvirtual pole near $D^* D$ threshold with a pole position $E_{\\rm pole} = -59\n(^{+53}_{-99}) (^{+2}_{-67})$ keV and an inverse scattering length\n$1/a_0=0.05(5)(^{+2}_{-2})$ fm$^{-1}$. The virtual pole turns into a loosely\nbound state pole if the pion mass in the TPE potential is extrapolated to the\nphysical value, $m_\\pi =135$ MeV. The potential at the physical pion mass is\nshown to give a semi-quantitative description of the $D^0 D^0\\pi^+$ mass\nspectrum at the LHCb.",
        "positive": "Lattice QCD Impact on Determination of CKM Matrix: Status and Prospects: Lattice QCD is an important tool for theoretical input for flavor physics.\nThere have been four reviews by the Flavour Lattice Averaging Group (FLAG).\nThis talk will review the current status of the magnitude of eight of the nine\nCKM matrix elements, borrowing heavily from the most recent FLAG review\n(co-authored by the speaker). Future prospects for improving the determination\nof the CKM matrix will be discussed."
    },
    {
        "anchor": "On the Eichten--Preskill Proposal for Lattice Chiral Gauge Theories: We have studied the Eichten--Preskill proposal for constructing lattice\nchiral gauge theories using both strong and weak coupling methods. The results\nindicate that this proposal is unlikely to work due to a dynamical behavior\nsimilar to that of the Smit--Swift proposal, which also does not give rise to\nchiral fermions.",
        "positive": "Can nonlocal Dirac operators be topologically proper ?: By examining the analyticity of a sequence of topologically-proper lattice\nDirac operators, we show that they tend to a nonlocal Dirac operator. This\nimplies that a nonlocal lattice Dirac operator can have exact zero modes\nsatisfying the Atiyah-Singer index theorem, in gauge backgrounds with nonzero\ntopological charge."
    },
    {
        "anchor": "From the Abelian projected flux tube to the dual Abelian Higgs model: A recent detailed study of the Q-anti-Q flux tube and its DAHM analysis is\nreported.",
        "positive": "Perturbative renormalization of $\u0394F = 2$ four-fermion operators\n  with the chirally rotated Schr\u00f6dinger functional: The chirally rotated Schr\\\"odinger functional ($\\chi$SF) renders the\nmechanism of automatic $O(a)$ improvement compatible with Schr\\\"odinger\nfunctional (SF) renormalization schemes. Here we define a family of\nrenormalization schemes based on the $\\chi$SF for a complete basis of $\\Delta F\n= 2$ parity-odd four-fermion operators. We compute the corresponding\nscale-dependent renormalization constants to one-loop order in perturbation\ntheory and obtain their NLO anomalous dimensions by matching to the\n$\\overline{\\textrm{MS}}$ scheme. Due to automatic $O(a)$ improvement, once the\n$\\chi$SF is renormalized and improved at the boundaries, the step scaling\nfunctions (SSF) of these operators approach their continuum limit with\n$O(a^{2})$ corrections without the need of operator improvement."
    },
    {
        "anchor": "$Z_N$ symmetry in $SU(N)$ gauge theories: We study $Z_N$ symmetry in $SU(N)$ gauge theories in the presence of matter\nfields in the fundamental representation, by restricting the lattice partition\nfunction integration to matter fields which are uniform in spatial directions\nand gauge fields with vanishing spatial components. In this approximation the\ngauge matter field interaction effectively reduces to a 1-dimensional gauged\nchain. This makes analytical calculations of the matter field contribution to\nthe Polyakov loop free energy possible. We show that in the limit of large\nnumber of temporal sites the explicit breaking of $Z_N$ symmetry in this free\nenergy vanishes, driven by dominance of the density of states. We argue that\nthe spatial links as well as the spatial modes of the matter fields determine\nthe boundaries separating regions where $Z_N$ symmetry is realised from rest of\nthe phase diagram.",
        "positive": "$B_c \\to B_{s(d)}$ form factors from lattice QCD: We present results of the first lattice QCD calculations of $B_c \\to B_s$ and\n$B_c \\to B_d$ weak matrix elements. Form factors across the entire physical\n$q^2$ range are then extracted and extrapolated to the physical-continuum limit\nbefore combining with CKM matrix elements to predict the semileptonic decay\nrates $\\Gamma(B_c^+ \\to B_s^0 \\overline{\\ell} \\nu_{\\ell}) = 26.2(1.2) \\times\n10^9 \\,\\text{s}^{-1}$ and $\\Gamma(B_c^+ \\to B^0 \\overline{\\ell} \\nu_{\\ell}) =\n1.65(10) \\times 10^9 \\,\\text{s}^{-1}$. The lattice QCD uncertainty is\ncomparable to the CKM uncertainty here. Results are derived from correlation\nfunctions computed on MILC Collaboration gauge configurations with a range of\nlattice spacings including 2+1+1 flavours of dynamical sea quarks in the Highly\nImproved Staggered Quark (HISQ) formalism. HISQ is also used for the\npropagators of the valence light, strange, and charm quarks. Two different\nformalisms are employed for the bottom quark: non-relativistic QCD (NRQCD) and\nheavy-HISQ. Checking agreement between these two approaches is an important\ntest of our strategies for heavy quarks on the lattice. From chained fits of\nNRQCD and heavy-HISQ data, we obtain the differential decay rates $d\\Gamma/ d\nq^2$ as well as integrated values for comparison to future experimental\nresults."
    },
    {
        "anchor": "Relative scale setting for two-color QCD with Nf=2 Wilson fermions: We determine the scale setting function and the pseudo-critical temperature\non the lattice in $N_f=2$ two-color QCD using the Iwasaki gauge and Wilson\nfermion actions. Although two-color QCD does not correspond to the real world,\nit is very useful as a good testing ground for three-color QCD. The scale\nsetting function gives the relative lattice spacings of simulations performed\nat different values of the bare coupling. It is a necessary tool for taking the\ncontinuum limit. Firstly, we measure the meson spectra for various combinations\nof ($\\beta,\\kappa$) and find a line of constant physics in $\\beta$--$\\kappa$\nplane. Next, we determine the scale setting function via $w_0$ scale in the\ngradient flow method. Furthermore, we estimate the pseudo-critical temperature\nat zero chemical potential from the chiral susceptibility. Combining these\nresults, we can discuss the QCD phase diagram in which both axes are given by\ndimensionless quantities, namely, the temperature normalized by the\npseudo-critical temperature on the lattice and the chemical potential\nnormalized by the pseudoscalar meson mass. It makes it easy to compare among\nseveral lattice studies and also makes it possible to compare theoretical\nanalyses and lattice studies in the continuum limit.",
        "positive": "Chiral Limit of Nucleon Lattice Electromagnetic Form Factors: We calculate electric and magnetic form factors of protons and neutrons in\nquenched Monte Carlo lattice QCD on a $16^3\\times 24$ lattice at $\\beta = 6.0$\nusing Wilson fermions. We employ a method which characterizes one of the\nnucleon fields as a fixed zero-momentum secondary source. Extrapolating the\noverall data set to the chiral limit, we find acceptable fits for either dipole\nor monopole forms and extract proton and neutron magnetic moments, the\nmagnitude of which are $10$ to $15\\%$ low compared to experiment. In the\nextrapolation of the dipole fit of the form factors, we find that the dipole to\nnucleon mass ratio is about $7\\%$ low compared to experiment. In addition, we\nobtain positive values of the neutron electric form factor, which, however, are\npoorly represented by a popular phenomenological form at intermediate to small\n$\\kappa$ values. A zero-momentum technique for extracting hadron magnetic\nmoments is briefly discussed and shown to yield unrealistically small magnetic\nmoment values."
    },
    {
        "anchor": "$\u03c0N \u03c3$ Term and Quark Spin Content of the Nucleon: We report results of our calculation on the $\\pi N\\sigma$ term and quark spin\ncontent of the nucleon on the quenched $16^3 \\times 24$ lattice at $\\beta =\n6.0$. The disconnected insertions which involve contributions from the sea\nquarks are calculated with the stochastic $Z_2$ noise algorithm. As a physical\ntest of the algorithm, we show that the forward matrix elements of the vector\nand pseudoscalar currents for the disconnected insertions are indeed consistent\nwith the known results of zero. We tried the Wuppertal smeared source and found\nit to be more noisy than the point source. With unrenormalized\n$m_q=4.42(17)$MeV, we find the $\\pi N\\sigma$ term to be $39.2\\pm 5.2$ MeV. The\nstrange quark condensate in the nucleon is large, i.e. $\\langle\nN|\\bar{s}s|N\\rangle = 1.16 \\pm 0.54$. For the quark spin content, we find\n$\\Delta u =0.78\\pm 0.07$, $\\Delta d =-0.42\\pm 0.07$, and $\\Delta s = -0.13\\pm\n0.06$. The flavor-singlet axial charge $g_A^1 = \\Delta \\Sigma =0.22\\pm 0.09 $.",
        "positive": "Exact lattice chiral symmetry in 2d gauge theory: We construct symmetry-preserving lattice regularizations of 2d QED with one\nand two flavors of Dirac fermions, as well as the `3450' chiral gauge theory,\nby leveraging bosonization and recently-proposed modifications of Villain-type\nlattice actions. The internal global symmetries act just as locally on the\nlattice as they do in the continuum, the anomalies are reproduced at finite\nlattice spacing, and in each case we find a sign-problem-free dual formulation."
    },
    {
        "anchor": "Looking behind the Standard Model with lattice gauge theory: Models for what may lie behind the Standard Model often require\nnon-perturbative calculations in strongly coupled field theory. This creates\nopportunities for lattice methods, to obtain quantities of phenomenological\ninterest as well as to address fundamental dynamical questions. I survey recent\nwork in this area.",
        "positive": "Renormalization of Currents for Massive Fermions: The renormalization of vector and axial-vector currents for massive fermions\n(in the ``Fermilab formalism'') is discussed. We give results for\nnon-degenerate masses, which are needed for semi-leptonic form factors."
    },
    {
        "anchor": "Scattering phaseshift formulas for mesons and baryons in elongated boxes: We derive L\\\"{u}scher phaseshift formulas for two-particle states in boxes\nelongated in one of the dimensions. Such boxes offer a cost-effective way of\nvarying the relative momentum of the particles. Boosted states in the elongated\ndirection, which allow wider access to energies, are also considered. The\nformulas for the various scenarios (moving and zero-momentum states in cubic\nand elongated boxes) are compared and relations between them are clarified. The\nresults are applicable to a wide set of meson-meson and meson-baryon elastic\nscattering processes, with the two-particle system having equal or unequal\nmasses.",
        "positive": "Stochastic method with low mode substitution for nucleon isovector\n  matrix elements: We introduce a stochastic sandwich method with low-mode substitution to\nevaluate the connected three-point functions. The isovector matrix elements of\nthe nucleon for the axial-vector coupling $g_A^3$, scalar couplings $g_S^3$ and\nthe quark momentum fraction $\\langle x\\rangle_{u -d}$ are calculated with\noverlap fermion on 2+1 flavor domain-wall configurations on a $24^3 \\times 64$\nlattice at $m_{\\pi} = 330$ MeV with lattice spacing $a = 0.114$ fm."
    },
    {
        "anchor": "The continuum limit of the static-light meson spectrum: We investigate the continuum limit of the low lying static-light meson\nspectrum using Wilson twisted mass lattice QCD with N_f = 2 dynamical quark\nflavours. We consider three values of the lattice spacing a ~ 0.051 fm, 0.064\nfm, 0.080 fm and various values of the pion mass in the range 280 MeV < m_PS <\n640 MeV. We present results in the continuum limit for light cloud angular\nmomentum j = 1/2, 3/2, 5/2 and for parity P = +, -. We extrapolate our results\nto physical quark masses, make predictions regarding the spectrum of B and B_s\nmesons and compare with available experimental results.",
        "positive": "Accelerating lattice quantum field theory calculations via interpolator\n  optimization using NISQ-era quantum computing: The only known way to study quantum field theories in non-perturbative\nregimes is using numerical calculations regulated on discrete space-time\nlattices. Such computations, however, are often faced with exponential\nsignal-to-noise challenges that render key physics studies untenable even with\nnext generation classical computing. Here, a method is presented by which the\noutput of small-scale quantum computations on Noisy Intermediate-Scale Quantum\nera hardware can be used to accelerate larger-scale classical field theory\ncalculations through the construction of optimized interpolating operators. The\nmethod is implemented and studied in the context of the 1+1-dimensional\nSchwinger model, a simple field theory which shares key features with the\nstandard model of nuclear and particle physics."
    },
    {
        "anchor": "Quenched Light Hadron Mass Spectrum and Decay Constants: the effects of\n  $O(a)$-Improvement at $\u03b2=6.2$: We compare the light hadron spectrum and decay constants for quenched QCD at\n$\\beta=6.2$ using an $O(a)$-improved nearest-neighbour Wilson fermion action\nwith those obtained using the standard Wilson fermion action on the same set of\n18 gauge configurations. For pseudoscalar meson masses in the range\n330--800~MeV, we find no significant difference between the results for the two\nactions. The scales obtained from the string tension and mesonic sector are\nconsistent, but differ from that derived from baryon masses. The ratio of the\npseudoscalar decay constant to the vector meson mass increases slowly with\nquark mass as observed experimentally.",
        "positive": "Constraints on the two-flavor QCD phase diagram from imaginary chemical\n  potential: We review our knowledge of the phase diagram of QCD as a function of\ntemperature, chemical potential and quark masses. The presence of tricritical\nlines at imaginary chemical potential mu=i pi/3 T, with known scaling behaviour\nin their vicinity, puts constraints on this phase diagram, especially in the\ncase of two light flavors. We show first results in our project to determine\nthe finite-temperature behaviour in the two-flavour chiral limit."
    },
    {
        "anchor": "Dynamical lattice computation of the Isgur-Wise functions tau_{1/2} and\n  tau_{3/2}: We perform a two-flavor dynamical lattice computation of the Isgur-Wise\nfunctions tau_{1/2} and tau_{3/2} at zero recoil in the static limit. We find\ntau_{1/2}(1) = 0.297(26) and tau_{3/2}(1) = 0.528(23) fulfilling Uraltsev's sum\nrule by around 80%. We also comment on a persistent conflict between theory and\nexperiment regarding semileptonic decays of B mesons into orbitally excited P\nwave D mesons, the so-called \"1/2 versus 3/2 puzzle\", and we discuss the\nrelevance of lattice results in this context.",
        "positive": "Testing Dimensional Reduction in SU(2) Gauge Theory: At high temperature, every $(d+1)$-dimensional theory can be reformulated as\nan effective theory in $d$ dimensions. We test the numerical accuracy of this\nDimensional Reduction for (3+1)-dimensional SU(2) by comparing perturbatively\ndetermined effective couplings with lattice results as the temperature is\nprogressively lowered. We observe an increasing disagreement between numerical\nand perturbative values from $T=4 T_c$ downwards, which may however be due to\nsomewhat different implementations of dimensional reduction in the two cases."
    },
    {
        "anchor": "Lattice Supersymmetry: Some Ideas from Low Dimensional Models: In the framework of the so called link approach we study exact lattice\nsupersymmetry for the simplest supersymmetric model: N=1 supersymmetry in D=1.\nThe model is described by a lattice with spacing a/2, thus containing twice as\nmany sites as the conventional one. The boson and fermion are related through a\n2pi/a momentum shift, which can provide an interpretation of them being species\ndoublers to each other. An exactly supersymmetric lattice action can be written\nwithin this scheme in momentum representation, which however turns out to be\nnon local in coordinate space.",
        "positive": "On strongly coupled quenched QED4, again: chiral symmetry breaking,\n  Goldstone mechanism and the nature of the continuum limit: We explore the possibility of a trivial continuum limit of strongly coupled\nquenched QED4 by contrasting our results with a Nambu--Jona Lasinio equation of\nstate. The data does not compare favorably with such scenario. We study in\ndetail the interplay of chiral symmetry breaking with the Goldstone mechanism,\nand clarify some puzzling features of past results."
    },
    {
        "anchor": "Determination of the Collins-Soper Kernel from Lattice QCD: We present lattice results for the non-perturbative Collins-Soper (CS)\nkernel, which describes the energy-dependence of transverse momentum-dependent\nparton distributions (TMDs). The CS kernel is extracted from the ratios of\nfirst Mellin moments of quasi-TMDs evaluated at different nucleon momenta.The\nanalysis is done with dynamical $N_f=2+1$ clover fermions for the CLS ensemble\nH101 ($a=0.0854\\,\\mathrm{fm}$, $m_{\\pi}=m_K=422\\,\\mathrm{MeV}$). The computed\nCS kernel is in good agreement with experimental extractions and previous\nlattice studies.",
        "positive": "The static-light baryon spectrum from twisted mass lattice QCD: We compute the static-light baryon spectrum by means of Wilson twisted mass\nlattice QCD using N_f = 2 flavors of sea quarks. As light u/d valence quarks we\nconsider quarks, which have the same mass as the sea quarks with corresponding\npion masses in the range 340 MeV < m_PS < 525 MeV, as well as partially\nquenched s quarks, which have a mass around the physical value. We consider all\npossible combinations of two light valence quarks, i.e. Lambda, Sigma, Xi and\nOmega baryons corresponding to isospin I = 0, 1/2, 1 and strangeness S = 0, -1,\n-2 as well as angular momentum of the light degrees of freedom j = 0, 1 and\nparity P = +, -. We extrapolate in the light u/d and in the heavy b quark mass\nto the physical point and compare with available experimental results. Besides\nexperimentally known positive parity states we are also able to predict a\nnumber of negative parity states, which have neither been measured in\nexperiments nor previously been computed by lattice methods."
    },
    {
        "anchor": "Parallel tempering algorithm applied to the deconfinement transition of\n  quenched QCD: QCD with infinite heavy quark masses exhibits a first-order thermal\ntransition which is driven by the spontaneous breaking of the global\n$\\mathcal{Z}_3$ center symmetry. We analyze the corresponding order parameter,\nnamely the Polyakov loop and its moments, and show, with a rigorous finite size\nscaling, that in the continuum limit the transition is of first order. We show\nthat the use of a parallel tempering algorithm can significantly reduce the\nlarge auto-correlation times which are mainly caused by the supercritical\nslowing down. As a result, we calculate the transition temperature $w_0 T_c$\nwith per-mill precision, and the latent heat, carrying out controlled continuum\nand infinite volume extrapolations.",
        "positive": "Blockspin transformation for finite temperature field theories with\n  gauge fields: A procedure is proposed to study QFT at zero or at finite temperature by a\nsequence of real space renormalization group (RG) or blockspin transformations.\nThey transform to effective theories on coarser and coarser lattices.The\nultimate aim is to compute constraint effective potentials, i.e. the free\nenergy as a function of suitable order parameters.From the free energy one can\nread off the thermodynamic behaviour of the theory, in particular the existence\nand nature of phase transitions. In a finite temperature QFT one begins with\neither one or a sequence of transformations which transform the original theory\ninto an effective theory on a three-dimensional lattice. Its effective action\nhas temperature dependent coefficients. Thereafter one may proceed with further\nblockspin transformations of the three-dimensional theory. Assuming a finite\nvolume, this can in principle be continued until one ends with a lattice with a\nsingle site. Its effective action is the constraint effective potential. In\neach RG-step, an integral over the high frequency part of the field has to be\nperformed. This is done perturbatively and requires the knowledge of bare\nfluctuation field propagators and of interpolation operators which enter into\nthe vertices. A detailed examination of these quantities is presented for\nscalar fields, abelian gauge fields and for Higgs fields, finite temperature is\nadmitted."
    },
    {
        "anchor": "Polarized Nucleon Structure Functions from Lattice QCD: We describe a high statistics quenched QCD calculation of the moments of the\npolarized deep-inelastic structure functions g_1 and g_2 of the proton and\nneutron.",
        "positive": "The sphaleron rate from Euclidean lattice correlators: an exploration: We show how the sphaleron rate (the Minkowski rate for topological charge\ndiffusion) can be determined by analytical continuation of the Euclidean\ntopological-charge-density two-point function, which we investigate on the\nlattice, using gradient flow to reduce noise and provide improved operators\nwhich more accurately measure topology. We measure the correlators on large,\nfine lattices in the quenched approximation at $1.5\\,T_c$ with high precision.\nBased on these data we first perform a continuum extrapolation at fixed\nphysical flow time and then extrapolate the continuum estimates to zero flow\ntime. The extrapolated correlators are then used to study the sphaleron rate by\nspectral reconstruction based on perturbatively motivated models."
    },
    {
        "anchor": "Critical Exponent for the Density of Percolating Flux: This paper is a study of some of the critical properties of a simple model\nfor flux. The model is motivated by gauge theory and is equivalent to the Ising\nmodel in three dimensions. The phase with condensed flux is studied. This is\nthe ordered phase of the Ising model and the high temperature, deconfined phase\nof the gauge theory. The flux picture will be used in this phase. Near the\ntransition, the density is low enough so that flux variables remain useful.\nThere is a finite density of finite flux clusters on both sides of the phase\ntransition. In the deconfined phase, there is also an infinite, percolating\nnetwork of flux with a density that vanishes as $T \\rightarrow T_{c}^{+}$. On\nboth sides of the critical point, the nonanalyticity in the total flux density\nis characterized by the exponent $(1-\\alpha)$. The main result of this paper is\na calculation of the critical exponent for the percolating network. The\nexponent for the density of the percolating cluster is $ \\zeta = (1-\\alpha) -\n(\\varphi-1)$. The specific heat exponent $\\alpha$ and the crossover exponent\n$\\varphi$ can be computed in the $\\epsilon$-expansion. Since $\\zeta <\n(1-\\alpha)$, the variation in the separate densities is much more rapid than\nthat of the total. Flux is moving from the infinite cluster to the finite\nclusters much more rapidly than the total density is decreasing.",
        "positive": "Excitations of Ising Strings on a Lattice: The 3d Ising model in the low temperature (ferromagnetic) phase describes\ndynamics of two-dimensional surfaces -- domain walls between clusters of\nparallel spins. The Kramers--Wannier duality maps these surfaces into\nworldsheets of confining strings in the Wegner's ${\\mathbb Z}_2$ gauge theory.\nWe study the excitation spectrum of long Ising strings by simulating the\n${\\mathbb Z}_2$ gauge theory on a lattice. We observe a strong mixing between\nstring excitations and the lightest glueball state and do not find indications\nfor light massive resonances on the string worldsheet."
    },
    {
        "anchor": "Hadronic form factors in Lattice QCD at small and vanishing momentum\n  transfer: The introduction of partially twisted boundary conditions allows weak and\nelectromagnetic form factors to be evaluated at specified values of the\nhadronic momenta (and hence momentum transfers) in lattice simulations. We\npresent and demonstrate this technique for the computation of the K->pi\nsemileptonic form factor at zero momentum transfer and for the electromagnetic\nform factor of the pion at arbitrarily small momentum transfers. These\nexploratory computations are carried out in full QCD with 3 flavours of sea\nquarks, but with only two values of m_u=m_d which limits our ability to perform\nthe chiral extrapolations. The results should therefore be viewed primarily as\na demonstration of the feasibility of the method. For the K-> pi form factor we\ncompare the new technique to the conventional approach and for the pion form\nfactor we assess our results for very small momentum transfer with the help of\nchiral perturbation theory.",
        "positive": "Finite size scaling of the balls in boxes model: We discuss the finite size behaviour in the canonical ensemble of the balls\nin boxes model. We compare theoretical predictions and numerical results for\nthe finite size scaling of cumulants of the energy distribution in the\ncanonical ensemble and perform a detailed analysis of the first and third order\nphase transitions which appear for different parameter values in the model."
    },
    {
        "anchor": "Equation of state and more from lattice regularized QCD: We present results from a calculation of the QCD equation of state with two\nlight (up, down) and one heavier (strange) quark mass performed on lattices\nwith three different values of the lattice cut-off. We show that also on the\nfinest lattice analyzed by us observables sensitive to deconfinement and chiral\nsymmetry restoration, respectively, vary most rapidly in the same temperature\nregime.",
        "positive": "Colour Confinement in the Lattice Landau Gauge QCD Simulation: The colour confinement criterion proposed by Kugo and Ojima is tested in the\nlattice Landau gauge QCD simulation. The renormalization effects are studied by\nmeasuring the gluon propagator, ghost propagator, three gluon vertex and the\nghost-antighost-gluon vertex."
    },
    {
        "anchor": "Phenomenology from 100 large lattices: We present a status report on simulations being done on $32^3 \\times 64$\nlattices at $\\beta = 6.0$ using quenched Wilson fermions. Phenomenologically\nrelevant results for the spectrum, decay constants, the kaon B-parameter $B_K$,\n$B_7$, $B_8$, semi-leptonic and $B\\to K^* \\gamma$ form factors are given based\non a statistical sample of 100 configurations.",
        "positive": "Domain Wall Fermions in Quenched Lattice QCD: We study the chiral properties and the validity of perturbation theory for\ndomain wall fermions in quenched lattice QCD at beta=6.0. The explicit chiral\nsymmetry breaking term in the axial Ward-Takahashi identity is found to be very\nsmall already at Ns=10, where Ns is the size of the fifth dimension, and its\nbehavior seems consistent with an exponential decay in Ns within the limited\nrange of Ns we explore. From the fact that the critical quark mass, at which\nthe pion mass vanishes as in the case of the ordinary Wilson-type fermion,\nexists at finite Ns, we point out that this may be a signal of the parity\nbroken phase and investigate the possible existence of such a phase in this\nmodel at finite Ns. The rho and pi meson decay constants obtained from the\nfour-dimensional local currents with the one-loop renormalization factor show a\ngood agreement with those obtained from the conserved currents."
    },
    {
        "anchor": "Lattice calculation of $\u03c7_{c0} \\rightarrow 2\u03b3$ decay width: We perform a lattice QCD calculation of the $\\chi_{c0} \\rightarrow 2\\gamma$\ndecay width using a model-independent method which does not require a momentum\nextrapolation of the corresponding off-shell form factors. The simulation is\nperformed on ensembles of $N_f=2$ twisted mass lattice QCD gauge configurations\nwith three different lattice spacings. After a continuum extrapolation, the\ndecay width is obtained to be\n$\\Gamma_{\\gamma\\gamma}(\\chi_{c0})=3.65(83)_{\\mathrm{stat}}(21)_{\\mathrm{lat.syst}}(66)_{\\mathrm{syst}}\\,\n\\textrm{keV}$. Albeit this large statistical error, our result is compatible\nwith the experimental results within 1.3$\\sigma$. Potential improvements of the\nlattice calculation in the future are also discussed.",
        "positive": "Lattice instanton action from 3D SU(2) Georgi-Glashow model: 3D Georgi-Glashow model is studied on the lattice in the London limit in an\ninfrared but an intermediate region before the screening appears. Abelian and\ninstanton dominances are observed after abelian projections in a unitary gauge\nand roughly in the maximally abelian gauge. Using an inverse Monte-Carlo\nmethod, we determine an effective instanton action in both gauges. When we\nrestrict ourselves to some regions of parameters $\\beta$ and $\\kappa$, we\nobtain an almost perfect instanton action, performing a block-spin\ntransformation on the dual lattice. It takes a form of a Coulomb gas and\nreproduces fairly well the string tension obtained analytically by Polyakov.\nThe almost perfect actions in both gauges look the same in the infrared region,\nwhich suggests gauge independence."
    },
    {
        "anchor": "Tensor network formulation for two-dimensional lattice $\\mathcal{N}=1$\n  Wess-Zumino model: Supersymmetric models with spontaneous supersymmetry breaking suffer from the\nnotorious sign problem in stochastic approaches. By contrast, the tensor\nnetwork approaches do not have such a problem since they are based on\ndeterministic procedures. In this work, we present a tensor network formulation\nof the two-dimensional lattice $\\mathcal{N}=1$ Wess-Zumino model while showing\nthat numerical results agree with the exact solutions for the free case.",
        "positive": "Finite Temperature Transition in Two Flavor QCD with Renormalization\n  Group Improved Action: The finite temperature transition or crossover in QCD with two degenerate\nWilson quarks is investigated using a renormalization group improved action. At\n$\\beta=2.0$ and 2.1 where $a^{-1} \\sim 1.0-1.2$ GeV, the expectation value of\nthe Polyakov loop and the pion screening mass on an $8^3 \\times 4$ lattice vary\nsmoothly with the hopping parameter through the transition/crossover. The quark\nscreening mass in the high temperature phase agrees well with that in the low\ntemperature phase calculated on an $8^4$ lattice. The smooth transition of the\nobservables is totally different from the sharp transition found for the\nstandard action at $\\beta=5.0$ and 5.1 where $a^{-1}$ is also $1.0-1.2$ GeV."
    },
    {
        "anchor": "Electroweak Transitions Involving Resonances: The increasing importance of hadronic resonances in our understanding of the\nStandard Model is underscored by recent advancements in lattice Quantum\nChromodynamics (QCD) calculations. We review recent developments, with a\nparticular emphasis on electroweak transitions that result in two-hadron final\nstates. Additionally, we present the finite-volume lattice QCD methodologies\nthat are pivotal in such studies in the context of preliminary results from the\n$B\\to \\pi\\pi\\ell\\bar{\\nu}$.",
        "positive": "Exact Local Bosonic Algorithm for Full QCD: We present an exact local bosonic algorithm for the simulation of dynamical\nfermions in lattice QCD. It is based on a non-hermitian polynomial\napproximation of the inverse of the quark matrix and a global Metropolis\naccept/reject correction of the systematic errors. We show that this algorithm\nis a real alternative to the Hybrid Monte Carlo algorithm."
    },
    {
        "anchor": "Multicanonical Study of Continuum Physics in the D=2 $O(3)$ Nonlinear\n  Sigma Model: Employing a variant of the Multicanonical Ensemble we study twisted spin\nconfigurations on periodic boxes in the $D=2$ $O(3)$ nonlinear sigma model for\n$\\beta$-values inbetween $1.55$ to $3.1$. The free energy difference of twisted\nspin configurations is determined from the constraint effective potential. The\nfinite size scaling behavior is in accordance with the asymptotically free\nnature of the continuum theory. Upon certain reasonable assumptions we\ndetermine the $\\Delta \\beta( \\beta)$-shift of the stiffness correlation length\n$\\xi_s$. The mass-gap as determined by our analysis is\n${m_0}=79.6(1.9)~\\Lambda_{latt}$. This value agrees with the analytical result\nof the thermodynamic Bethe Ansatz ${m_0}=80.1~\\Lambda_{latt}$.",
        "positive": "Gauge invariance of color confinement due to the dual Meissner effect\n  caused by Abelian monopoles: The mechanism of non-Abelian color confinement is studied in SU(2) lattice\ngauge theory in terms of the Abelian fields and monopoles extracted from\nnon-Abelian link variables without adopting gauge fixing.\n  Firstly, the static quark-antiquark potential and force are computed with the\nAbelian and monopole Polyakov loop correlators, and the resulting string\ntensions are found to be identical to the non-Abelian string tension. These\npotentials also show the scaling behavior with respect to the change of lattice\nspacing.\n  Secondly, the profile of the color-electric field between a quark and an\nantiquark is investigated with the Abelian and monopole Wilson loops. The\ncolor-electric field is squeezed into a flux tube due to monopole supercurrent\nwith the same Abelian color direction. The parameters corresponding to the\npenetration and coherence lengths show the scaling behavior, and the ratio of\nthese lengths, i.e, the Ginzburg-Landau parameter, indicates that the vacuum\ntype is near the border of the type1 and type2 (dual) superconductor.\n  These results are summarized that the Abelian fundamental charge defined in\nan arbitrary color direction is confined inside a hadronic state by the dual\nMeissner effect. As the color-neutral state in any Abelian color direction\ncorresponds to the physical color-singlet state, this effect explains\nnon-Abelian color confinement and supports the existence of a gauge-invariant\nmechanism of color confinement due to the dual Meissner effect caused by\nAbelian monopoles."
    },
    {
        "anchor": "Gribov Copies and Gauge Fixing in Lattice Gauge Theories: We address the problem of the gauge fixing versus Gribov copies in lattice\ngauge theories. For the Landau gauge, results show that a suitable combination\nof evolutionary algorithms with traditional steepest descent methods identifies\nthe global maximum of the optimisation function. We discuss the performance of\nthe combined algorithm on small cubic lattices for SU(2) and SU(3).",
        "positive": "Locality and Efficient Evaluation of Lattice Composite Fields:\n  Overlap-Based Gauge Operators: We propose a novel general approach to locality of lattice composite fields,\nwhich in case of QCD involves locality in both quark and gauge degrees of\nfreedom. The method is applied to gauge operators based on the overlap Dirac\nmatrix elements, showing for the first time their local nature on realistic\npath-integral backgrounds. The framework entails a method for efficient\nevaluation of such non-ultralocal operators, whose computational cost is\nvolume-indepenent at fixed accuracy, and only grows logarithmically as this\naccuracy approaches zero. This makes computation of useful operators, such as\noverlap-based topological density, practical. The key notion underlying these\nfeatures is that of exponential insensitivity to distant fields, made rigorous\nby introducing the procedure of statistical regularization. The scales\nassociated with insensitivity property are useful characteristics of non-local\ncontinuum operators."
    },
    {
        "anchor": "Multi-Grid Lanczos: We present a Lanczos algorithm utilizing multiple grids that reduces the\nmemory requirements both on disk and in working memory by one order of\nmagnitude for RBC/UKQCD's 48I and 64I ensembles at the physical pion mass. The\nprecision of the resulting eigenvectors is on par with exact deflation.",
        "positive": "Properties of the Z(3) Interface in (2+1)-D SU(3) Gauge Theory: A study is made of some properties of this interface in the SU(3) pure gauge\ntheory in 2+1 dimensions. At high temperatures, the interface tension is\nmeasured and shows agreement with the perturbative prediction. Near the\ncritical temperature, the behaviour of the interface is examined, and its\nfluctuations compared to a scalar field theory model."
    },
    {
        "anchor": "Partially quenched chiral perturbation theory without $\u03a6_0$: This paper completes the argument that lattice simulations of partially\nquenched QCD can provide quantitative information about QCD itself, with the\naid of partially quenched chiral perturbation theory. A barrier to doing this\nhas been the inclusion of $\\Phi_0$, the partially quenched generalization of\nthe $\\eta'$, in previous calculations in the partially quenched effective\ntheory. This invalidates the low energy perturbative expansion, gives rise to\nmany new unknown parameters, and makes it impossible to reliably calculate the\nrelation between the partially quenched theory and low energy QCD. We show that\nit is straightforward and natural to formulate partially quenched chiral\nperturbation theory without $\\Phi_0$, and that the resulting theory contains\nthe effective theory for QCD without the $\\eta'$. We also show that previous\nresults, obtained including $\\Phi_0$, can be reinterpreted as applying to the\ntheory without $\\Phi_0$. We contrast the situation with that in the quenched\neffective theory, where we explain why it is necessary to include $\\Phi_0$.\n  We also compare the derivation of chiral perturbation theory in partially\nquenched QCD with the standard derivation in unquenched QCD. We find that the\nformer cannot be justified as rigorously as the latter, because of the absence\nof a physical Hilbert space. Finally, we present an encouraging result:\nunphysical double poles in certain correlation functions in partially quenched\nchiral perturbation theory can be shown to be a property of the underlying\ntheory, given only the symmetries and some plausible assumptions.",
        "positive": "Correlations in fluctuating geometries: We compare two definitions of connected correlation functions in fluctuating\ngeometries. We show results of the MC simulations for 4D dynamical\ntriangulation in the elongated phase and compare them with the exact\ncalculations of correlation functions in the branched polymer model."
    },
    {
        "anchor": "The sign problem and the Lefschetz thimble: Recently, we have proposed a novel approach (arxiv:1205.3996) to deal with\nthe sign problem that hinders Monte Carlo simulations of many quantum field\ntheories (QFTs). The approach consists in formulating the QFT on a Lefschetz\nthimble. In this paper we concentrate on the application to a scalar field\ntheory with a sign problem. In particular, we review the formulation and the\njustification of the approach, and we also describe the Aurora Monte Carlo\nalgorithm that we are currently testing.",
        "positive": "SU(N_c) gauge theories at deconfinement: The deconfinement transition in SU($N_c$) Yang--Mills is investigated by\nMonte Carlo simulations of the gauge theory discretized on a spacetime lattice.\nWe present new results for $ 4 \\le N_c \\le 8$ (in particular, for $N_c = 5$ and\n$N_c = 7$), which are analysed together with previously published results. The\nincreased amount of data, the improved statistics and simulations closer to the\ncontinuum limit provide us with better control over systematic errors. After\nperforming the thermodynamic limit, numerical results for the ratio of the\ncritical temperature $T_c$ over the square root of the string tension\n$\\sqrt{\\sigma}$ obtained on lattices with temporal extensions $N_t = 5,6,7,8$\nare extrapolated to the continuum limit. The continuum results at fixed $N_c$\nare then extrapolated to $N_c = \\infty$. We find that our data are accurately\ndescribed by the formula $T_c/\\sqrt{\\sigma} = 0.5949(17) + 0.458(18)/N_c^2$.\nPossible systematic errors affecting our calculations are also discussed."
    },
    {
        "anchor": "Euclidean Dynamical Triangulations Revisited: We conduct numerical simulations of a model of four dimensional quantum\ngravity in which the path integral over continuum Euclidean metrics is\napproximated by a sum over combinatorial triangulations. At fixed volume the\nmodel contains a discrete Einstein-Hilbert term with coupling $\\kappa$ and\nlocal measure term with coupling $\\beta$ that weights triangulations according\nto the number of simplices sharing each vertex. We map out the phase diagram in\nthis two dimensional parameter space and compute a variety of observables that\nyield information on the nature of any continuum limit. Our results are\nconsistent with a line of first order phase transitions with a latent heat that\ndecreases as $\\kappa\\to\\infty$. We find a Hausdorff dimension along the\ncritical line that approaches $D_H=4$ for large $\\kappa$ and a spectral\ndimension that is consistent with $D_s=\\frac{3}{2}$ at short distances. These\nresults are broadly in agreement with earlier works on Euclidean dynamical\ntriangulation models which utilize degenerate triangulations and/or different\nmeasure terms and indicate that such models exhibit a degree of universality.",
        "positive": "Two-Dimensional Seven-State Potts Model Under External Magnetic Field: The two-dimensional Potts Model with seven states under external field is\nstudied using a cluster algorithm. Cluster size distribution and the\nfluctuations in the average cluster size provide helpful information on the\norder of phase transitions."
    },
    {
        "anchor": "Qubit Regularization and Qubit Embedding Algebras: Qubit regularization is a procedure to regularize the infinite dimensional\nlocal Hilbert space of bosonic fields to a finite dimensional one, which is a\ncrucial step when trying to simulate lattice quantum field theories on a\nquantum computer. When the qubit-regularized lattice quantum fields preserve\nimportant symmetries of the original theory, qubit regularization naturally\nenforces certain algebraic structures on these quantum fields. We introduce the\nconcept of qubit embedding algebras (QEAs) to characterize this algebraic\nstructure associated with a qubit regularization scheme. We show a systematic\nprocedure to derive QEAs for the O(N) lattice spin models and the SU(N) lattice\ngauge theories. While some of the QEAs we find were discovered earlier in the\ncontext of the D-theory approach, our method shows that QEAs are far more\nricher. A more complete understanding of the QEAs could be helpful in\nrecovering the fixed points of the desired quantum field theories.",
        "positive": "Static quark anti-quark pair in SU(2) gauge theory: We study singlet and triplet correlation functions of static quark anti-quark\npair defined through gauge invariant time-like Wilson loops and Polyakov loop\ncorrelators in finite temperature SU(2) gauge theory. We use the Luescher-Weisz\nmultilevel algorithm, which allows to calculate these correlators at very low\ntemperatures. We observe that the naive separation of singlet and triplet\nstates in general does not hold non-perturbatively, however, is recovered in\nthe limit of small separation and the temperature dependence of the\ncorresponding correlators is indeed very different."
    },
    {
        "anchor": "A 0-dimensional counter-example to rooting?: We provide an example of a 0-dimensional field theory where rooting does not\nwork.",
        "positive": "Nucleon axial charge from quenched lattice QCD with domain wall fermions\n  and improved gauge action: In our previous DWF calculation with the Wilson gauge action at $\\beta=6.0$\n($a^{-1}\\simeq$ 1.9 GeV) on a $16^3 \\times 32 \\times 16$ lattice, we found that\n$\\Ga$ had a fairly strong dependence on the quark mass. A simple linear\nextrapolation of $\\Ga$ to the chiral limit yielded a value that was almost a\nfactor of two smaller than the experimental one. Here we report our recent\nstudy of this issue. In particular, we investigate possible errors arising from\nfinite lattice volume, especially in the lighter quark mass region. We employ a\nRG-improved gauge action (DBW2), which maintains very good chiral behavior even\non a coarse lattice ($a^{-1}\\simeq$ 1.3 GeV), in order to perform simulations\nat large physical volume ($> (2{\\rm fm})^3$). Our preliminary results suggest\nthat the finite volume effect is significant."
    },
    {
        "anchor": "Does the 2d Higgs-Yukawa Model Have a Symmetric Phase at Small Yukawa\n  Coupling Region?: We show that at arbitrary value of the scalar self coupling and small Yukawa\ncoupling $y$ the 2d Higgs-Yukawa model with Z(2) symmetry remains in the broken\nphase and the model is asymptotically free: $y \\to 0$ as the cut-off $\\Lambda\n\\to \\infty$. This is in agreement with a recent conjecture based on numerical\nsimulation results.",
        "positive": "Neutron Electric Dipole Moment from Beyond the Standard Model: We present an update on our calculations of the matrix elements of the CP\nviolating quark and gluon chromo-EDM operators, as well as the operators these\nmix with, such as the QCD Theta-term. Their contribution to the neutron EDM is\nobtained by extrapolating the $F_3$ form factor of a vector current to zero\nmomentum transfer. The calculation is being done using valence Wilson-clover\nquarks on HISQ background configurations generated by the MILC collaboration."
    },
    {
        "anchor": "PDFs in small boxes: PDFs can be studied directly using lattice QCD by evaluating matrix elements\nof non-local operators. A number of groups are pursuing numerical calculations\nand investigating possible systematic uncertainties. One systematic that has\nreceived less attention is the effect of calculating in a finite spacetime\nvolume. Here we present first attempts to assess the role of the finite volume\nfor spatially non-local operators. We find that these matrix elements may\nsuffer from large finite-volume artifacts and more careful investigation is\nneeded.",
        "positive": "Lattice status of gluonia/glueballs: I briefly review lattice QCD calculations that study the 0++ glueball and\ndiscuss implications for light flavour singlet 0++ mesons."
    },
    {
        "anchor": "Matrix product states and variational methods applied to critical\n  quantum field theory: We study the second-order quantum phase-transition of massive real scalar\nfield theory with a quartic interaction ($\\phi^4$ theory) in (1+1) dimensions\non an infinite spatial lattice using matrix product states (MPS). We introduce\nand apply a naive variational conjugate gradient method, based on the\ntime-dependent variational principle (TDVP) for imaginary time, to obtain\napproximate ground states, using a related ansatz for excitations to calculate\nthe particle and soliton masses and to obtain the spectral density. We also\nestimate the central charge using finite-entanglement scaling. Our value for\nthe critical parameter agrees well with recent Monte Carlo results, improving\non an earlier study which used the related DMRG method, verifying that these\ntechniques are well-suited to studying critical field systems. We also obtain\ncritical exponents that agree, as expected, with those of the transverse Ising\nmodel. Additionally, we treat the special case of uniform product states (mean\nfield theory) separately, showing that they may be used to investigate\nnon-critical quantum field theories under certain conditions.",
        "positive": "New approach to canonical partition functions computation in $N_f=2$\n  lattice QCD at finite baryon density: We propose and test a new approach to computation of canonical partition\nfunctions in lattice QCD at finite density. We suggest a few steps procedure.\nWe first compute numerically the quark number density for imaginary chemical\npotential $i\\mu_{qI}$. Then we restore the grand canonical partition function\nfor imaginary chemical potential using fitting procedure for the quark number\ndensity. Finally we compute the canonical partition functions using high\nprecision numerical Fourier transformation. Additionally we compute the\ncanonical partition functions using known method of the hopping parameter\nexpansion and compare results obtained by two methods in the deconfining as\nwell as in the confining phases. The agreement between two methods indicates\nthe validity of the new method. Our numerical results are obtained in two\nflavor lattice QCD with clover improved Wilson fermions."
    },
    {
        "anchor": "More about the Grassmann tensor renormalization group: We derive a general formula of the tensor network representation for\n$d$-dimensional lattice fermions with ultra-local interactions, including\nWilson fermions, staggered fermions, and domain-wall fermions. The Grassmann\ntensor is concretely defined with auxiliary Grassmann variables that play a\nrole in bond degrees of freedom. Compared to previous works, our formula does\nnot refer to the details of lattice fermions and is derived by using the\nsingular value decomposition for the given Dirac matrix without any ad-hoc\ntreatment for each fermion. We numerically test our formula for free Wilson and\nstaggered fermions and find that it properly works for them. We also find that\nWilson fermions show better performance than staggered fermions in the tensor\nrenormalization group approach, unlike the Monte Carlo method.",
        "positive": "Excitation Spectra in a Heavy-Light Meson-Meson System: A system of two static quarks, at fixed distances r, and two light quarks is\nstudied on an anisotropic lattice. Excitations by operators emphasizing quark\nor gluon degrees of freedom are examined. The maximum entropy method is applied\nin the spectral analysis. These simulations ultimately aim at learning about\nmechanisms of hadronic interaction."
    },
    {
        "anchor": "Euclidean relativistic quantum mechanics - scattering asymptotic\n  conditions: We discuss the formulation of the scattering asymptotic condition in a\nrelativistic quantum theory formulated in terms of reflection positive\nEuclidean Green functions.",
        "positive": "2d quantum gravity with discrete edge lengths: An approximation of the Standard Regge Calculus (SRC) was proposed by the\n$Z_2$-Regge Model ($Z_2$RM). There the edge lengths of the simplicial complexes\nare restricted to only two possible values, both always compatible with the\ntriangle inequalities. To examine the effect of discrete edge lengths, we\ndefine two models to describe the transition from the $Z_2$RM to the SRC. These\nmodels allow to choose the number of possible link lengths to be $n =\n{4,8,16,32,64,...}$ and differ mainly in the scaling of the quadratic link\nlengths. The first extension, the $X^1_n$-Model, keeps the edge lengths limited\nand still behaves rather similar to the \"spin-like\" $Z_2$RM. The vanishing\ncritical cosmological constant is reproduced by the second extension, the\n$X^C_n$-Model, which allows for increasing edge lengths. In addition the area\nexpectation values are consistent with the scaling relation of the SRC."
    },
    {
        "anchor": "Studying glueball masses in non-Abelian LGT with the LW algorithm: We address a study of glueball masses in the confining regime of SU(2) in D=3\nusing an algorithm inspired by the multi-level scheme. Our method, which\nexploits the locality of the action to achieve high precision results, is based\non a technique already used for compact QED, and generalises it to the\nnon-Abelian case. We discuss the main features of this method, in comparison\nwith other algorithms that have been used in similar studies.",
        "positive": "The Elusive Asymptotic Behavior of the High-Temperature Expansion of the\n  Hierarchical Ising Model: We present a differential formulation of the recursion formula of the\nhierarchical model which provides a recursive method of calculation for the\nhigh-temperature expansion. We calculate the first 30 coefficients of the high\ntemperature expansion of the magnetic susceptibility of the Ising hierarchical\nmodel with 12 significant digits. We study the departure from the approximation\nwhich consists of identifying the coefficients with the values they would take\nif a $[0,1]$ Pad\\'e approximant were exact. We show that, when the order in the\nhigh-temperature expansion increases, the departure from this approximation\ngrows more slowly than for nearest neighbor models. As a consequence, the value\nof the critical exponent $\\gamma $ estimated using Pad\\'e approximants\nconverges very slowly and the estimations using 30 coefficients have errors\nlarger than 0.05. A (presumably much) larger number of coefficients is\nnecessary to obtain the critical exponents with a precision comparable to the\nprecision obtained for nearest neighbor models with less coefficients. We also\ndiscuss the possibility of constructing models where a $[0,1]$ Pad\\'e\napproximant would be exact."
    },
    {
        "anchor": "Lattice Gauge Field Interpolation for Chiral Gauge Theories: The importance of lattice gauge field interpolation for our recent\nnon-perturbative formulation of chiral gauge theory is emphasized. We\nillustrate how the requisite properties are satisfied by our recent\nfour-dimensional non-abelian interpolation scheme, by going through the simpler\ncase of U(1) gauge fields in two dimensions.",
        "positive": "Adaptive Optimization of Wave Functions for Lattice Field Models: The accuracy of Green Function Monte Carlo (GFMC) simulations can be greatly\nimproved by a clever choice of the approximate ground state wave function that\ncontrols configuration sampling. This trial wave function typically depends on\nmany free parameters whose fixing is a non trivial task. Here, we discuss a\ngeneral purpose adaptive algorithm for their non-linear optimization. As a non\ntrivial application we test the method on the two dimensional Wess-Zumino\nmodel, a relativistically invariant supersymmetric field theory with\ninteracting bosonic and fermionic degrees of freedom."
    },
    {
        "anchor": "Automatic differentiation for error analysis of Monte Carlo data: Automatic Differentiation (AD) allows to determine exactly the Taylor series\nof any function truncated at any order. Here we propose to use AD techniques\nfor Monte Carlo data analysis. We discuss how to estimate errors of a general\nfunction of measured observables in different Monte Carlo simulations. Our\nproposal combines the $\\Gamma$-method with Automatic differentiation, allowing\nexact error propagation in arbitrary observables, even those defined via\niterative algorithms. The case of special interest where we estimate the error\nin fit parameters is discussed in detail. We also present a freely available\nfortran reference implementation of the ideas discussed in this work.",
        "positive": "The pseudoscalar meson electromagnetic form factor at high $Q^2$ from\n  full lattice QCD: We give an accurate determination of the vector (electromagnetic) form\nfactor, $F(Q^2)$, for a light pseudoscalar meson up to squared momentum\ntransfer $Q^2$ values of 6 $\\mathrm{GeV}^2$ for the first time from full\nlattice QCD, including $u$, $d$, $s$ and $c$ quarks in the sea at multiple\nvalues of the lattice spacing. Our results show good control of lattice\ndiscretisation and sea quark mass effects. We study a pseudoscalar meson made\nof valence $s$ quarks but the qualitative picture obtained applies also to the\n$\\pi$ meson, relevant to upcoming experiments at Jefferson Lab. We find that\n$Q^2F(Q^2)$ becomes flat in the region between $Q^2$ of 2 $\\mathrm{GeV}^2$ and\n6 $\\mathrm{GeV}^2$, with a value well above that of the asymptotic perturbative\nQCD expectation, but well below that of the vector-meson dominance pole form\nappropriate to low $Q^2$ values. Our calculations show that we can reach higher\n$Q^2$ values in future to shed further light on where the perturbative QCD\nresult emerges."
    },
    {
        "anchor": "Study of the conformal hyperscaling relation through the Schwinger-Dyson\n  equation: We study corrections to the conformal hyperscaling relation in the conformal\nwindow of the large Nf QCD by using the ladder Schwinger-Dyson (SD) equation as\na concrete dynamical model. From the analytical expression of the solution of\nthe ladder SD equation, we identify the form of the leading mass correction to\nthe hyperscaling relation. We find that the anomalous dimension, when\nidentified through the hyperscaling relation neglecting these corrections,\nyields a value substantially lower than the one at the fixed point \\gamma_m^*\nfor large mass region. We further study finite-volume effects on the\nhyperscaling relation, based on the ladder SD equation in a finite space-time\nwith the periodic boundary condition. We find that the finite-volume\ncorrections on the hyperscaling relation are negligible compared with the mass\ncorrection. The anomalous dimension, when identified through the finite-size\nhyperscaling relation neglecting the mass corrections as is often done in the\nlattice analyses, yields almost the same value as that in the case of the\ninfinite space-time neglecting the mass correction, i.e., a substantially lower\nvalue than \\gamma_m^* for large mass. We also apply the finite-volume SD\nequation to the chiral-symmetry-breaking phase and find that when the theory is\nclose to the critical point such that the dynamically generated mass is much\nsmaller than the explicit breaking mass, the finite-size hyperscaling relation\nis still operative. We also suggest a concrete form of the modification of the\nfinite-size hyperscaling relation by including the mass correction, which may\nbe useful to analyze the lattice data.",
        "positive": "Stochastic Renormalization Group and Gradient Flow in Scalar Field\n  Theory: Recently, the connections between gradient flow and renormalization group\nhave been explored analytically and numerically. Gradient flow (when modified\nby a field rescaling) can be characterized as a continuous blocking\ntransformation. In this work, we draw a connection between gradient flow and\nfunctional renormalization group by describing how FRG can be represented by a\nstochastic process, and how the stochastic observables relate to gradient flow\nobservables. The relation implies correlator scaling formulae that can be\napplied numerically in lattice simulations. We present preliminary results on\nanomalous dimensions obtained from such measurements in the context of\n3-dimensional lattice $\\phi^4$ theory."
    },
    {
        "anchor": "Perturbative Renormalization and Mixing of Quark and Glue\n  Energy-Momentum Tensors on the Lattice: We report the renormalization and mixing constants to one-loop order for the\nquark and gluon energy-momentum (EM) tensor operators on the lattice. A unique\naspect of this mixing calculation is the definition of the glue EM tensor\noperator. The glue operator is comprised of gauge-field tensors constructed\nfrom the overlap Dirac operator. The resulting perturbative calculations are\nperformed using methods similar to the Kawai approach using the Wilson action\nfor all QCD vertices and the overlap Dirac operator to define the glue EM\ntensor. Our results are used to connect the lattice QCD results of quark and\nglue momenta and angular momenta to the $\\overline{\\text{MS}}$ scheme at input\nscale $\\mu$",
        "positive": "Isovector Axial Charge and Form Factors of Nucleons from Lattice QCD: I present an overview of the calculations of the isovector axial vector form\nfactor of the nucleon, $G_A(Q^2)$, using lattice QCD. Based on a comparison of\nresults from various collaborations, a case is made that lattice results are\nnow consistent within 10\\%. A similar level of uncertainty is found also in the\naxial charge $g_A^{u-d}$, the mean squared axial charge radius, $\\langle r_A^2\n\\rangle$, the induced pseudoscalar charge $g_P^\\ast$, and the pion-nucleon\ncoupling $g_{\\pi NN}$. These lattice results for $G_A(Q^2)$ are already\ncompatible with those obtained from the recent MINER$\\nu$A experiment but lie\n2-3$\\sigma$ higher than the phenomenological extraction from the old\n$\\nu$-deuterium bubble chamber scattering data for $Q^2 > 0.3$~GeV${}^2$. Fits\nto our data show that the dipole ansatz does not have enough parameters to\nparameterize the form factor over the range $0 \\le Q^2 \\le 1$~GeV${}^2$,\nwhereas even a $z^2$ truncation of the $z$-expansion or a low order Pad\\'e are\nsufficient. Looking ahead, lattice QCD calculations will provide increasingly\nprecise results over the range $0 \\le Q^2 \\lesssim 1$~GeV${}^2$, and\nMINER$\\nu$A-like experiments will extend the range to $Q^2 \\sim 2$~GeV${}^2$ or\nhigher. To increase precision of lattice data to the percent level, new\ndevelopments are needed to address two related issues: the exponentially\nfalling signal-to-noise ratio in all nucleon correlation functions and removing\nexcited state contributions. Nevertheless, even with the current methodology,\nsignificant reduction in errors is expected over the next few years with higher\nstatistics data on more ensembles closer to the physical point."
    },
    {
        "anchor": "Strings of diquark-quark (QQ)Q baryon before phase transition: We explore the limit at which the effective baryonic Y-string model of the\njunction approaches the mesonic stringlike behavior. We calculate and compare\nthe numerical values of the static potential and energy-density correlators of\ndiquark-quark and quark-antiquark configurations. The gauge model is pure\nYang-Mills $SU(3)$ lattice gauge theory at coupling $\\beta=6.0$ and finite\ntemperature. The diquark setup is approximated as two quarks confined within a\nsphere of radius $0.1$ fm. The lattice data of the potential and energy show\nthat the string binding the diquark-quark configuration displays an identical\nbehavior to the quark-antiquark confining string. However, with the temperature\nincrease to a small enough neighborhood of the critical point $T_{c}$, the\ngluonic similarities between the two systems do not manifest neither at short\nnor intermediate distance scales $R<1.0$ fm. The comparison between the\npotential and the second moment of the action-density correlators for both\nsystems shows significant splitting. This suggests that subsisted baryonic\ndecoupled states overlap with the mesonic spectrum. The baryonic junction's\nmodel for the potential and the profile returns a good fit to the numerical\nlattice data of the diquark-quark arrangement. However, near the critical\npoint, the mesonic string displays large deviations compared to fits of the\ncorresponding quark-antiquark data.",
        "positive": "Logarithmic Corrections to the Equation of State in the SU(2)xSU(2)\n  Nambu - Jona-Lasinio Model: We present results from a Monte Carlo simulation of the Nambu - Jona-Lasinio\nmodel, with continuous SU(2)xSU(2) chiral symmetry, in four Euclidean\ndimensions. Different model equations of state, corresponding to different\ntheoretical scenarios, are tested against the order parameter data. The results\nare sensitive to necessary assumptions about the shape and extent of the\nscaling region. Our best fits favour a trivial scenario in which the\nlogarithmic corrections are qualitatively similar to those predicted by the\nlarge N_f approximation. This is supported by a separate analysis of finite\nvolume corrections for data taken directly in the chiral limit."
    },
    {
        "anchor": "Gluon Field Digitization for Quantum Computers: Simulations of gauge theories on quantum computers require the digitization\nof continuous field variables. Digitization schemes that uses the minimum\namount of qubits are desirable. We present a practical scheme for digitizing\n$SU(3)$ gauge theories via its discrete subgroup $S(1080)$. The $S(1080)$\nstandard Wilson action cannot be used since a phase transition occurs as the\ncoupling is decreased, well before the scaling regime. We proposed a modified\naction that allows simulations in the scaling window and carry out classical\nMonte Carlo calculations down to lattice spacings of order $a\\approx 0.08$ fm.\nWe compute a set of observables with sub-percent precision at multiple lattice\nspacings and show that the continuum extrapolated value agrees with the full\n$SU(3)$ results. This suggests that this digitization scheme provides\nsufficient precision for NISQ-era QCD simulations.",
        "positive": "Strongly Bound Dibaryon with Maximal Beauty Flavor from Lattice QCD: We report the first lattice QCD study of the heavy dibaryons in which all six\nquarks have the bottom (beauty) flavor. Performing a state-of-the-art lattice\nQCD calculation we find clear evidence for a deeply bound\n$\\Omega_{bbb}$-$\\Omega_{bbb}$ dibaryon in the $^1S_0$ channel, as a pole\nsingularity in the $S$-wave $\\Omega_{bbb}$-$\\Omega_{bbb}$ scattering amplitude\nwith a binding energy $-81(_{-16}^{+14})$ MeV. With such a deep binding,\nCoulomb repulsion serves only as a perturbation on the ground state wave\nfunction of the parameterized strong potential and may shift the strong binding\nonly by a few percent. Considering the scalar channel to be the most bound for\nsingle flavored dibaryons, we conclude this state is the heaviest possible most\ndeeply bound dibaryon in the visible universe."
    },
    {
        "anchor": "Non-perturbative evaluation of cSW for smeared link clover fermion and\n  Iwasaki gauge action: We performed a rough estimate of the non-perturbative value of the clover\nterm coefficient cSW for the APE stout link Wilson fermion. We varied the\nnumber of smearings from Nsmear=1 to 6 and adopted beta values roughly\ncorresponding to the lattice spacing of 0.1 fm. We used the Schroedinger\nfunctional technique for an evaluation of cSW and found that cSW decreases\nmonotonically as we increase Nsmear but has a 10% order of deviation from the\ntree level value for Nsmear=6.",
        "positive": "Exploring walking behavior in SU(3) gauge theory with 4 and 8 HISQ\n  quarks: We present the report of the LatKMI collaboration on the lattice QCD\nsimulation for the cases of 4 and 8 flavors. The Nf=8 in particular is\ninteresting from the model-building point of view: The typical walking\ntechnicolor model with the large anomalous dimension is the so-called\none-family model (Farhi-Susskind model). Thus we explore the walking behavior\nin LQCD with 8 HISQ quarks by comparing with the 4-flavor case (in which the\nchiral symmetry is spontaneously broken). We report preliminary results on the\nspectrum, analyzed through the chiral perturbation theory and the finite-size\nhyperscaling, and we discuss the availability of the Nf=8 QCD to the\nphenomenology."
    },
    {
        "anchor": "Weakly coupled conformal gauge theories on the lattice: Results are reported for the beta-function of weakly coupled conformal gauge\ntheories on the lattice, SU(3) with Nf=14 fundamental and Nf=3 sextet fermions.\nThe models are chosen to be close to the upper end of the conformal window\nwhere perturbation theory is reliable hence a fixed point is expected. The\nstudy serves as a test of how well lattice methods perform in the weakly\ncoupled conformal cases. We also comment on the 5-loop beta-function of two\nmodels close to the lower end of the conformal window, SU(3) with Nf=12\nfundamental and Nf=2 sextet fermions.",
        "positive": "Krylov space solvers for shifted linear systems: We investigate the application of Krylov space methods to the solution of\nshifted linear systems of the form (A+\\sigma) x - b = 0 for several values of\n\\sigma simultaneously, using only as many matrix-vector operations as the\nsolution of a single system requires. We find a suitable description of the\nproblem, allowing us to understand known algorithms in a common framework and\ndeveloping shifted methods basing on short recurrence methods, most notably the\nCG and the BiCGstab solvers. The convergence properties of these shifted\nsolvers are well understood and the derivation of other shifted solvers is\neasily possible. The application of these methods to quark propagator\ncalculations in quenched QCD using Wilson and Clover fermions is discussed and\nnumerical examples in this framework are presented. With the shifted CG method\nan optimal algorithm for staggered fermions is available."
    },
    {
        "anchor": "Charmonium resonances on the lattice: The nature of resonances and excited states near decay thresholds is encoded\nin scattering amplitudes, which can be extracted from single-particle and\nmultiparticle correlators in finite volumes. Lattice calculations have only\nrecently reached the precision required for a reliable study of such\ncorrelators. The distillation method represents a significant improvement\ninsofar as it simplifies quark contractions and allows one to easily extend the\noperator basis used to construct interpolators. We present preliminary results\non charmonium bound states and resonances on the Nf=2+1 CLS ensembles. The long\nterm goal of our investigation is to understand the properties of the X\nresonances that do not fit into conventional models of quark-antiquark mesons.\nWe tune various parameters of the distillation method and the charm quark mass.\nAs a first result, we present the masses of the ground and excited states in\nthe 0++ and 1-- channels.",
        "positive": "On The Origin of the OZI Rule in QCD: The OZI rule is prominent in hadronic phenomena only because OZI violation is\ntypically an order of magnitude smaller than expected from large N_c arguments.\nWith its standard ^3P_0 pair creation operator for hadronic decays by flux tube\nbreaking, the quark model respects the OZI rule at tree level and exhibits the\ncancellations between OZI-violating meson loop diagrams required for this\ndramatic suppression. However, if the quark model explanation for these\ncancellations is correct, then OZI violation would be expected to be large in\nthe nonet with the same quantum numbers as the pair creation operator: the\n0^{++} mesons. Experiment is currently unable to identify these mesons, but we\nreport here on a lattice QCD calculation which confirms that the OZI rule\narises from QCD in the vector and axial vector mesons as observed, and finds a\nlarge violation of the rule in the scalar mesons as anticipated by the quark\nmodel. In view of this result, we make some remarks on possible connections\nbetween the ^3P_0 pair creation model, scalar mesons, and the U_A(1) anomaly\nresponsible for the large OZI violation which drives the \\eta' mass. In\nparticular, we note that our result favors the large N_c and not the instanton\ninterpretation of the solution to the \\eta' mass problem."
    },
    {
        "anchor": "Analytic calculation of the mass gap in U(1)_{2+1} lattice gauge theory: An analytic calculation of the photon mass gap M of compact U(1)_{2+1} in the\nHamiltonian formalism is performed utilizing the first four Hamiltonian moments\nwith respect to a one-plaquette mean field state in the plaquette expansion\nmethod. Scaling of M is clearly evident at and beyond the transition from\nstrong to weak coupling. The scaling behaviour agrees well with the range of\nresults from numerical calculations.",
        "positive": "Precision $\u03a5$ Spectroscopy and Fundamental Parameters From NRQCD: We present results from a high precision NRQCD simulation of the quenched\n$\\Upsilon$ system at $\\beta = 6$. We demonstrate a variety of important lattice\ntechniques, including the perturbative improvement of actions, tadpole\nimprovement, and multicorrelated fits for extracting the spectrum of excited\nstates. We present new determinations of $\\alpha_s(M_Z)$ and $M_b$, two\nfundamental parameters of the Standard Model."
    },
    {
        "anchor": "One loop calculation of SUSY Ward-Takahashi identity on lattice with\n  Wilson fermion: One loop correction to the SUSY Ward-Takahashi identity is calculated on\nlattice with Wilson fermion. The supersymmetry on lattice is broken explicitly\nby the gluino mass and the lattice artifact. We should fine tune parameters in\nthe theory to the point given by the additive mass correction in order to\neliminate the breaking effect of lattice artifact. It is shown that the\nadditive mass correction appearing from the SUSY Ward-Takahashi identity\ncoincide with that from the axial $U(1)_R$ symmetry as was suggested by Curci\nand Veneziano. Two important symmetries of the super Yang-Mills theory can be\nrecovered simultaneously in the continuum with a single fine tuning.\n  Operator mixing of the supercurrent are also investigated. We find that the\nsupercurrent mixes only with a gauge invariant current $T_\\mu$ which is related\nto the gamma-trace anomaly.",
        "positive": "A Microscopic study of Magnetic monopoles in Topological Insulators: In this article, we analyze a magnetic monopole in topological insulators.\nThe monopole obtain a fractional electric charge because of the Witten effect.\nWe consider this system with a microscopic view by adding the Wilson term to\nthe ordinary Dirac Hamiltonian. The Wilson term yields the positive mass shift\nto the effective mass of the electrons, then the curved domain-wall is\ndynamically generated around the monopole. The zero-modes of the electrons are\nlocalized on the domain-wall, which can be identified as the source of the\nelectric charge."
    },
    {
        "anchor": "Dirac b quark on the lattice: We perform the first study of treating b, c, and s quarks as Dirac fermions\nin lattice QCD with exact chiral symmetry. On a 32^3 60 lattice with 1/a ~ 7.68\nGeV, we compute point-to-point quark propagators, and measure the\ntime-correlation functions for mesons with quark contents b_bbar, c_bbar,\ns_bbar, and c_cbar. The lowest-lying meson mass spectra, the pseudoscalar decay\nconstants, and the b and c quark masses are determined.",
        "positive": "Nucleon Axial and Electromagnetic Form Factors: We present results for the isovector axial, induced pseudoscalar, electric,\nand magnetic form factors of the nucleon. The calculations were done using\n$2+1+1$-flavor HISQ ensembles generated by the MILC collaboration with lattice\nspacings $a \\approx$ 0.12, 0.09, 0.06$\\mathrm{fm}$ and pion masses $M_\\pi\n\\approx$ 310, 220, 130$\\mathrm{MeV}$. Excited-states contamination is\ncontrolled by using four-state fits to two-point correlators and by comparing\ntwo- versus three-states in three-point correlators. The $Q^2$ behavior is\nanalyzed using the model independent z-expansion and the dipole ansatz. Final\nresults for the charge radii and magnetic moment are obtained using a\nsimultaneous fit in $M_\\pi$, lattice spacing $a$ and finite volume."
    },
    {
        "anchor": "Critical Dynamics of the Hybrid Monte Carlo Algorithm: We investigate the critical dynamics of the Hybrid Monte Carlo algorithm\napproaching the chiral limit of standard Wilson fermions. Our observations are\nbased on time series of lengths O(5000) for a variety of observables. The\nlattice sizes are 16^3 x 32 and 24^3 x 40. We work at beta=5.6, and\nkappa=0.156, 0.157, 0.1575, 0.158, with 0.83 > m_pi/m_rho > 0.55. We find\nsurprisingly small integrated autocorrelation times for local and extended\nobservables. The dynamical critical exponent $z$ of the exponential\nautocorrelation time is compatible with 2. We estimate the total computational\neffort to scale between V^2 and V^2.25 towards the chiral limit.",
        "positive": "Phase diagram of the quantum O(2)-model in 2+1 dimensions: The quantum O(2) model in 2+1 dimensions is studied by simulating the 3d O(2)\nmodel near criticality. Finite densities are introduced by a non-zero chemical\npotential mu, and the worm algorithm is used to circumvent the sign problem.\nThe renormalisation is discussed in some detail. We find that the onset value\nof the chemical potential coincides with the mass gap. The mu-dependence of the\ndensity rules out Bose-Einstein condensation and might be compatible with an\ninteracting Fermi gas. The mu-T phase diagram is explored using the density and\nthe magnetic susceptibility. In the cold, but dense regime of the phase\ndiagram, we find a superfluid phase."
    },
    {
        "anchor": "Confinement of color: open problems and perspectives: Some basic features of confinement are reviewed, in particular the symmetry\npatterns of the dual dynamics. Open problems and possible directions of\nprogress are discussed.",
        "positive": "Effective field theories for QCD with rooted staggered fermions: Even highly improved variants of lattice QCD with staggered fermions show\nsignificant violations of taste symmetry at currently accessible lattice\nspacings. In addition, the \"rooting trick\" is used in order to simulate with\nthe correct number of light sea quarks, and this makes the lattice theory\nnonlocal, even though there is good reason to believe that the continuum limit\nis in the correct universality class. In order to understand scaling\nviolations, it is thus necessary to extend the construction of the Symanzik\neffective theory to include rooted staggered fermions. We show how this can be\ndone, starting from a generalization of the renormalization-group approach to\nrooted staggered fermions recently developed by one of us. We then explain how\nthe chiral effective theory follows from the Symanzik action, and show that it\nleads to \"rooted\" staggered chiral perturbation theory as the correct chiral\ntheory for QCD with rooted staggered fermions. We thus establish a direct link\nbetween the renormalization-group based arguments for the correctness of the\ncontinuum limit and the success of rooted staggered chiral perturbation theory\nin fitting numerical results obtained with the rooting trick. In order to\ndevelop our argument, we need to assume the existence of a standard\npartially-quenched chiral effective theory for any local partially-quenched\ntheory. Other technical, but standard, assumptions are also required."
    },
    {
        "anchor": "Interactions of two and three mesons including higher partial waves from\n  lattice QCD: We study two- and three-meson systems composed either of pions or kaons at\nmaximal isospin using Monte Carlo simulations of lattice QCD. Utilizing the\nstochastic LapH method, we are able to determine hundreds of two- and\nthree-particle energy levels, in nine different momentum frames, with high\nprecision. We fit these levels using the relativistic finite-volume formalism\nbased on a generic effective field theory in order to determine the parameters\nof the two- and three-particle K-matrices. We find that the statistical\nprecision of our spectra is sufficient to probe not only the dominant $s$-wave\ninteractions, but also those in $d$ waves. In particular, we determine for the\nfirst time a term in the three-particle K-matrix that contains two-particle $d$\nwaves. We use three $N_f=2+1$ CLS ensembles with pion masses of $200$, $280$,\nand $340\\;$MeV. This allows us to study the chiral dependence of the scattering\nobservables, and compare to the expectations of chiral perturbation theory.",
        "positive": "Comments on k-Strings at Large N: We present a computation of the k-string tension in the large N limit of the\ntwo dimensional lattice Yang-Mills theory. It is well known that the problems\nof computing the partition function and the Wilson loop can be both reduced to\na unitary matrix integral which has a third order phase transition separating\nweak and strong coupling. We give an explicit computation of the interaction\nenergy for k-strings in the large N limit when k/N is held constant and\nnon-zero. In this limit, the interaction energy is finite and attractive. We\nshow that, in the strong coupling phase, the k -> N - k duality is realized as\na first order phase transition. We also show that the lattice k-string tension\nreduces to the expected Casimir scaling in the continuum limit."
    },
    {
        "anchor": "Noncompact Gauge-Invariant Simulations of U(1), SU(2), and SU(3): We have applied a new gauge-invariant, noncompact, Monte Carlo method to\nsimulate the $U(1)$, $SU(2)$, and $SU(3)$ gauge theories on $8^4$ and $12^4$\nlattices. The Creutz ratios of the Wilson loops agree with the exact results\nfor $U(1)$ for $\\beta \\ge 0.5$ apart from a renormalization of the charge. The\n$SU(2)$ and $SU(3)$ Creutz ratios robustly display quark confinement at $\\beta\n= 0.5$ and $\\beta = 2$, respectively. At much weaker coupling, the $SU(2)$ and\n$SU(3)$ Creutz ratios agree with perturbation theory after a renormalization of\nthe coupling constant. For $SU(3)$ the scaling window is near $ \\beta = 2 $,\nand the relation between the string tension $\\sigma $ and our lattice QCD\nparameter $ \\Lambda_L $ is $\\sqrt{\\sigma} \\approx 5 \\Lambda_L$.",
        "positive": "Topological properties of $CP^{N-1}$ models in the large-$N$ limit: We investigate, by numerical simulations on a lattice, the\n$\\theta$-dependence of 2$d$ $CP^{N-1}$ models for a range of $N$ going from 9\nto 31, combining imaginary $\\theta$ and simulated tempering techniques to\nimprove the signal-to-noise ratio and alleviate the critical slowing down of\nthe topological modes. We provide continuum extrapolations for the second and\nfourth order coefficients in the Taylor expansion in $\\theta$ of the vacuum\nenergy of the theory, parameterized in terms of the topological susceptibility\n$\\chi$ and of the so-called $b_2$ coefficient. Those are then compared with\navailable analytic predictions obtained within the $1/N$ expansion, pointing\nout that higher order corrections might be relevant in the explored range of\n$N$, and that this fact might be related to the non-analytic behavior expected\nfor $N = 2$. We also consider sixth-order corrections in the $\\theta$\nexpansion, parameterized in terms of the so-called $b_4$ coefficient: in this\ncase our present statistical accuracy permits to have reliable non-zero\ncontinuum estimations only for $N \\leq 11$, while for larger values we can only\nset upper bounds. The sign and values obtained for $b_4$ are compared to\nlarge-$N$ predictions, as well as to results obtained for $SU(N_c)$ Yang-Mills\ntheories, for which a first numerical determination is provided in this study\nfor the case $N_c = 2$."
    },
    {
        "anchor": "The spontaneous generation of magnetic fields at high temperature in\n  SU(2)-gluodynamics on a lattice: The spontaneous generation of the chromomagnetic field at high temperature is\ninvestigated in a lattice formulation of the SU(2)-gluodynamics. The procedure\nof studying this phenomenon is developed. The Monte Carlo simulations of the\nfree energy on the lattices 2 \\times 8^3, 2\\times 16^3 and 4 \\times 8^3 at\nvarious temperatures are carried out. The creation of the field is indicated by\nmeans of the \\chi^2-analysis of the data set accumulating 5-10 millions MC\nconfigurations. A comparison with the results of other approaches is done.",
        "positive": "Energies of B_s meson excited states - a lattice study: This is a follow-up to our earlier work on the energies and radial\ndistributions of heavy-light mesons. The heavy quark is taken to be static\n(infinitely heavy) and the light quark has a mass about that of the strange\nquark. We now concentrate on the energies of the excited states with higher\nangular momentum and with a radial node. A new improvement is the use of\nhypercubic blocking in the time direction.\n  The calculation is carried out with dynamical fermions on a 16 cubed times 32\nlattice with a lattice spacing approximately 0.1 fm generated using a\nnon-perturbatively improved clover action.\n  In nature the closest equivalent of this heavy-light system is the B_s meson,\nwhich allows us to compare our lattice calculations to experimental results\n(where available) or to give a prediction where the excited states,\nparticularly P-wave states, should lie. We pay special attention to the\nspin-orbit splitting, to see which one of the states (for a given angular\nmomentum L) has the lower energy. An attempt is made to understand these\nresults in terms of the Dirac equation."
    },
    {
        "anchor": "Determination of the QCD coupling from the static energy and the free\n  energy: We present two determinations of the strong coupling \\(\\alpha_s\\). The first\none is from the static energy at three-loop accuracy, and may be considered an\nupdate of earlier determinations by some of us. The new analysis includes new\nlattice data at smaller lattice spacings, and reaches distances as short as\n\\(0.0237\\,{\\rm fm}\\). We present a comprehensive and detailed estimate of the\nerror sources that contribute to the uncertainty of the final result,\n$\\alpha_s(M_Z)=0.11660^{+0.00110}_{-0.00056}$. The second determination is\nbased on lattice data for the singlet free energy at finite temperature up to\ndistances as small as \\(0.0081\\,{\\rm fm}\\), from which we obtain\n$\\alpha_s(M_Z)=0.11638^{+0.0009 5}_{-0.00087}$.",
        "positive": "Chiral Extrapolations and the Covariant Small Scale Expansion: We calculate the nucleon and the delta mass to fourth order in a covariant\nformulation of the small scale expansion. We analyze lattice data from the MILC\ncollaboration and demonstrate that the available lattice data combined with our\nknowledge of the physical values for the nucleon and delta masses lead to\nconsistent chiral extrapolation functions for both observables up to fairly\nlarge pion masses. This holds in particular for very recent data on the delta\nmass from the QCDSF collaboration. The resulting pion-nucleon sigma term is\nsigma_{piN} = 48.9 MeV. This first quantitative analysis of the quark-mass\ndependence of the structure of the Delta(1232) in full QCD within chiral\neffective field theory suggests that (the real part of) the nucleon-delta\nmass-splitting in the chiral limit, Delta_0 = 0.33 GeV, is slightly larger than\nat the physical point. Further analysis of simultaneous fits to nucleon and\ndelta lattice data are needed for a precision determination of the properties\nof the first excited state of the nucleon."
    },
    {
        "anchor": "Noncommutativity Approach to Supersymmetry on the Lattice: SUSY Quantum\n  Mechanics and an Inconsistency: It is argued that the noncommutativity approach to fully supersymmetric field\ntheories on the lattice suffers from an inconsistency. Supersymmetric quantum\nmechanics is worked out in this formalism and the inconsistency is shown both\nin general and explicitly for that system, as well as for the Abelian super BF\nmodel.",
        "positive": "Perturbative Renormalization of Wilson line operators: We present results for the renormalization of gauge invariant nonlocal\nfermion operators which contain a Wilson line, to one loop level in lattice\nperturbation theory. Our calculations have been performed for Wilson/clover\nfermions and a wide class of Symanzik improved gluon actions. The extended\nnature of such `long-link' operators results in a nontrivial renormalization,\nincluding contributions which diverge linearly as well as logarithmically with\nthe lattice spacing, along with additional finite factors. We present\nnonperturbative prescriptions to extract the linearly divergent contributions."
    },
    {
        "anchor": "Temperature dependence of topological susceptibility using gradient flow: We study temperature dependence of the topological susceptibility with the\n$N_{f}=2+1$ flavors Wilson fermion. We have two major interests in this paper.\nOne is a comparison of gluonic and fermionic definitions of the topological\nsusceptibility. Two definitions are related by the chiral Ward-Takahashi\nidentity but their coincidence is highly non-trivial for the Wilson fermion. By\napplying the gradient flow both for the gauge and quark fields we find a good\nagreement of these two measurements. The other is a verification of a\nprediction of the dilute instanton gas approximation at low temperature region\n$T_{pc}< T<1.5T_{pc}$, for which we confirm the prediction that the topological\nsusceptibility decays with power $\\chi_{t}\\propto(T/T_{pc})^{-8}$ for three\nflavors QCD.",
        "positive": "Lattice QCD on PCs?: Current PC processors are equipped with vector processing units and have\nother advanced features that can be used to accelerate lattice QCD programs.\nClusters of PCs with a high-bandwidth network thus become powerful and\ncost-effective machines for numerical simulations."
    },
    {
        "anchor": "QCD correlation functions and instantons: QCD point-to-point correlation functions at distances .2-1 fm are very\ndifferent for different channels, and they tell us a lot about inter-quark\ninteractions. Recent studies based on experimental data, 'instanton liquid'\napproach and lattice measurements are reviewed. Agreement between all of them\nshow that instanton-induced forces dominate the light quark physics, and new\nfindings by Negele et al, that {\\it hadrons survive 'cooling'}, make this\nstatement obvious. We also argue that {\\it chiral symmetery restoration} is due\nto breaking of the 'instanton liquid' into {\\it polarized} 'instanton\nmolecules'. % For Lattice-93 proceedings, figures and % hard copies available\nat request, sorry.",
        "positive": "Nuclear Parity Violation from Lattice QCD: The electroweak interaction at the level of quarks and gluons are well\nunderstood from precision measurements in high energy collider experiments.\nRelating these fundamental parameters to Hadronic Parity Violation in nuclei\nhowever remains an outstanding theoretical challenge. One of the most\ninteresting observables in this respect is the parity violating hadronic\nneutral current: it is hard to measure in collider experiments and is thus the\nleast constrained observable of the Standard Model. Precision measurements of\nparity violating transitions in nuclei can help to improve these constraints.\nIn these systems however, the weak interaction is masked by effects of the\nseven orders of magnitude stronger non-perturbative strong interaction.\nTherefore, in order to relate experimental measurements of the parity violating\npion-nucleon couplings to the fundamental Lagrangian of the SM, these\nnon-perturbative effects have to be well understood. In this paper, we are\ngoing to present a Lattice QCD approach for computing the $\\Delta I{=}2$ parity\nviolating matrix element in proton proton scattering. This process does not\ninvolve disconnected diagrams in the isospin symmetric limit and is thus a\nperfect testbed for studying the feasibility of the more involved calculation\nof the parity violating pion-nucleon coupling."
    },
    {
        "anchor": "Continuum reduction in large N gauge theories: These are notes associated with three lectures given at the 49th Cracow\nSchool of Theoretical physics where a pedagogical explanation of the\nGross-Witten transition, Eguchi-Kawai reduction and continuum reduction were\ngiven, followed by a description of the numerical computation of fermionic\nobservables in the 't Hooft limit of large N gauge theory.",
        "positive": "QCD with Two Light Dynamical Chirally Improved Quarks: Results for the excited meson and baryon spectrum with two flavors of\nChirally Improved sea quarks are presented. We simulate several ensembles with\npion masses ranging from 250 to 600 MeV and extrapolate to the physical pion\nmass. Strange quarks are treated within the partially quenched approximation.\nUsing the variational method, we investigate the content of the states. Among\nothers, we discuss the flavor singlet/octet content of Lambda states. In\ngeneral, our results compare well with experiment, in particular we get very\ngood agreement with the Lambda(1405) and confirm its flavor singlet nature."
    },
    {
        "anchor": "Universality and massive excitations in 3d 3-state Potts model: The mass spectrum of the 3d 3-state Potts model is considered in the broken\nphase (a) near the second order Ising critical point in the\ntemperature-magnetic field plane and (b) near the weakly first order transition\npoint at zero magnetic field. In the case (a), the mass spectrum is compared\nwith the prediction from universality of mass ratios in the 3d Ising class; in\nthe case (b) a mass ratio is determined to be compared with the corresponding\none in the spectrum of screening masses of the (3+1)d SU(3) pure gauge theory\nat finite temperature in the deconfined phase near the transition.",
        "positive": "Progress on the Microscopic Spectrum of the Dirac Operator for QCD with\n  Wilson Fermions: Starting from the chiral Lagrangian for Wilson fermions at nonzero lattice\nspacing we have obtained compact expressions for all spectral correlation\nfunctions of the Hermitian Wilson Dirac operator in the $\\epsilon$-domain of\nQCD with dynamical quarks. We have also obtained the distribution of the\nchiralities over the real eigenvalues of the Wilson Dirac operator for any\nnumber of flavors. All results have been derived for a fixed index of the Dirac\noperator. An important effect of dynamical quarks is that they completely\nsuppress the inverse square root singularity in the spectral density of the\nHermitian Wilson Dirac operator. The analytical results are given in terms of\nan integral over a diffusion kernel for which the square of the lattice spacing\nplays the role of time. This approach greatly simplifies the expressions which\nwe here reduce to the evaluation of two-dimensional integrals."
    },
    {
        "anchor": "Weak coupling expansion of massless QCD with a Ginsparg-Wilson fermion\n  and axial U(1) anomaly: We discuss the weak coupling expansion of massless QCD with the Dirac\noperator which is derived by Neuberger based on the overlap formalism and\nsatisfies the Ginsparg-Wilson relation. The axial U(1) anomaly associated to\nthe chiral transformation proposed by Luscher is calculated as an application\nand is shown to have the correct form of the topological charge density for\nperturbative backgrounds. The coefficient of the anomaly is evaluated as a\nwinding number related to a certain five-dimensional fermion propagator.",
        "positive": "Thermodynamics of 2 and 3 flavour QCD: We discuss recent results on the thermodynamics of QCD in the presence of\nlight dynamical quark degrees of freedom. In particular, we concentrate on an\nanalysis of the flavour and quark mass dependence of the QCD phase diagram, the\nequation of state and the transition temperature. Moreover, we present recent\nresults on the heavy quark free energy."
    },
    {
        "anchor": "Quark Mass dependence at Two Loops for Meson Properties: This talks contains a short introduction to Chiral Perturbation Theory and\nthe existing calculations to two-loop order in the mesonic sector. I include a\ndiscussion on which quantities the expansion can be organized in. The present\nbest values of the Low-Energy-Constants as determined from continuum physics\nare given as well as the assumptions underlying the fits to experimental data.\nI present plots of masses, decay constants and $f_+(0)$ in $K_{\\ell3}$ as a\nfunction of quark or meson masses. The talk ends with a list of things for\nwhich it would be extremely useful to have good results from lattice QCD\ncalculations.",
        "positive": "First Order Phase Transition in Finite Density QCD using the modulus of\n  the Dirac Determinant: We report results of simulations of strong coupling, finite density QCD\nobtained within a MFA inspired approach where the fermion determinant in the\nintegration measure is replaced by its absolute value. Contrary to the standard\nwisdom, we show that within this approach a clear signal of a phase transition\nappears with a critical chemical potential in extremely good agreement with the\nresults obtained with the Glasgow algorithm. The modulus of the fermion\ndeterminant seems therefore to preserve some of the relevant physical\nproperties of the system. We also analyze the dependence of our results on the\nquark mass, including both the chiral and large mass limit, and the theory in\nthe quenched approximation."
    },
    {
        "anchor": "Strong coupling analysis of Aoki phase in Staggered-Wilson fermions: We study strong-coupling lattice QCD with staggered-Wilson fermions, with an\nemphasis on the possibility of spontaneous parity breaking. We perform\neffective potential analysis in the strong-coupling limit. From gap equations\nwe find the pion condensate becomes nonzero in some range of a mass parameter,\nwhich indicates the existence of the parity-broken phase. We also find massless\npions and PCAC relations around the second-order phase boundary. These results\nsuggest that we can take the chiral limit by tuning a mass parameter in lattice\nQCD with staggered-Wilson fermions as with the Wilson fermion.",
        "positive": "Two-flavor QCD at finite quark or isospin density: We exploit analytic continuation to prolongate to the region of real chemical\npotentials the (pseudo)critical lines of QCD with two degenerate staggered\nfermions at nonzero temperature and quark or isospin density obtained in the\nregion of imaginary chemical potentials. We determine the curvatures at zero\nchemical potential and quantify the deviation between the cases of finite quark\nand of finite isospin chemical potential. In both circumstances deviations from\na quadratic dependence of the pseudocritical lines on the chemical potential\nare clearly seen. We try different extrapolations and, for the nonzero isospin\nchemical potential, confront them with the results of direct Monte Carlo\nsimulations. We also find that, as for the finite quark chemical potential, an\nimaginary isospin chemical potential can strengthen the transition till turning\nit into strong first order."
    },
    {
        "anchor": "$m_c/m_s$ with Brillouin fermions: We present a calculation of the ratio of the charm quark mass to the strange\nquark mass. Using the Brillouin improved Wilson action, we are able to\ncalculate this ratio in a single framework, using a relativistic fermionic\naction throughout. The calculation is carried out on selected ensembles of two\nflavor clover improved lattices produced by the QCDSF collaboration, allowing\nan extrapolation to the continuum, to infinite volume and to the physical pion\nmass.",
        "positive": "Cosmic Strings on the Lattice: We develop a formalism for the quantization of topologically stable\nexcitations in the 4-dimensional abelian lattice gauge theory. The excitations\nare global and local (Abrikosov-Nielsen-Olesen) strings and monopoles. The\noperators of creation and annihilation of string states are constructed; the\nstring Green functions are represented as a path integral over random surfaces.\nTopological excitations play an important role in the early universe. In the\nbroken symmetry phase of the $U(1)$ spin model, closed global cosmic strings\narise, while in the Higgs phase of the noncompact gauge-Higgs model, local\ncosmic strings are present. The compact gauge-Higgs model also involves\nmonopoles. Then the strings can break if their ends are capped by monopoles.\nThe topology of the Euclidean string world sheets are studied by numerical\nsimulations."
    },
    {
        "anchor": "Non-trivial phase structure of $N_f=3$ QCD with $O(a)$-improved Wilson\n  fermion at zero temperature: JLQCD collaboration recently started the $N_f=3$ QCD simulations with the\n$O(a)$-improved Wilson fermion action employing an exact fermion algorithm\ndeveloped for odd number of quark flavors. It is found that this theory has an\nunexpected non-trivial phase structure in the $(\\beta,\\kappa)$ plane even at\nzero temperature. A detailed study is made to understand the nature of the\nobserved phase transitions and to find the way of avoiding untolerably large\nlattice artifacts associated with the phase transition.",
        "positive": "Electric form factors of the octet baryons from lattice QCD and chiral\n  extrapolation: We apply a formalism inspired by heavy baryon chiral perturbation theory with\nfinite-range regularization to dynamical $2+1-$flavor CSSM/QCDSF/UKQCD\nCollaboration lattice QCD simulation results for the electric form factors of\nthe octet baryons. The electric form factor of each octet baryon is\nextrapolated to the physical pseudoscalar masses, after finite-volume\ncorrections have been applied, at six fixed values of $Q^2$ in the range\n0.2-1.3 GeV$^2$. The extrapolated lattice results accurately reproduce the\nexperimental form factors of the nucleon at the physical point, indicating that\nomitted disconnected quark loop contributions are small. Furthermore, using the\nresults of a recent lattice study of the magnetic form factors, we determine\nthe ratio $\\mu_p G^p_E/G^p_M$. This quantity decreases with $Q^2$ in a way\nqualitatively consistent with recent experimental results."
    },
    {
        "anchor": "The Kaon B-parameter with the Wilson Quark Action using Chiral Ward\n  Identities: We present a detailed description of the method and results of our\ncalculation of the kaon B parameter using the Wilson quark action in quenched\nQCD at $\\beta=5.9-6.5$. The mixing problem of the $\\Delta s=2$ four-quark\noperators is solved non-perturbatively with full use of chiral Ward identities.\nWe find $B_K(NDR, 2 GeV)=0.562(64)$ in the continuum limit, which agrees with\nthe value obtained with the Kogut-Susskind quark action.",
        "positive": "(Approximate) Low-Mode Averaging with a new Multigrid Eigensolver: We present a multigrid based eigensolver for computing low-modes of the\nHermitian Wilson Dirac operator. For the non-Hermitian case multigrid methods\nhave already replaced conventional Krylov subspace solvers in many lattice QCD\ncomputations. Since the $\\gamma_5$-preserving aggregation based interpolation\nused in our multigrid method is valid for both, the Hermitian and the\nnon-Hermitian case, inversions of very ill-conditioned shifted systems with the\nHermitian operator become feasible. This enables the use of multigrid within\nshift-and-invert type eigensolvers. We show numerical results from our MPI-C\nimplementation of a Rayleigh quotient iteration with multigrid. For\nstate-of-the-art lattice sizes and moderate numbers of desired low-modes we\nachieve speed-ups of an order of magnitude and more over PARPACK. We show\nresults and develop strategies how to make use of our eigensolver for\ncalculating disconnected contributions to hadronic quantities that are noisy\nand still computationally challenging. Here, we explore the possible benefits,\nusing our eigensolver for low-mode averaging and related methods with high and\nlow accuracy eigenvectors. We develop a low-mode averaging type method using\nonly a few of the smallest eigenvectors with low accuracy. This allows us to\navoid expensive exact eigensolves, still benefitting from reduced statistical\nerrors."
    },
    {
        "anchor": "Thermodynamics of SU(3) Lattice Gauge Theory: The pressure and the energy density of the $SU(3)$ gauge theory are\ncalculated on lattices with temporal extent $N_\\tau = 4$, 6 and 8 and spatial\nextent $N_\\sigma =16$ and 32. The results are then extrapolated to the\ncontinuum limit. In the investigated temperature range up to five times $T_c$\nwe observe a $15\\%$ deviation from the ideal gas limit. We also present new\nresults for the critical temperature on lattices with temporal extent $N_\\tau =\n8$ and 12. At the corresponding critical couplings the string tension is\ncalculated on $32^4$ lattices to fix the temperature scale. An extrapolation to\nthe continuum limit yields $T_c/\\sqrt{\\sigma} = 0.629(3)$. We furthermore\npresent results on the electric and magnetic condensates as well as the\ntemperature dependence of the spatial string tension. These observables suggest\nthat the temperature dependent running coupling remains large even at $T\\simeq\n5T_c$. For the spatial string tension we find $\\sqrt{\\sigma_s}/T = 0.566(13)\ng^2(T)$ with $g^2(5T_c) \\simeq 1.5$.",
        "positive": "New insight into the Berezinskii-Kosterlitz-Thouless phase transition: We investigate the 2d XY model by using the constraint angle action, which\nbelongs to the class of topological lattice actions. These actions violate\nimportant features usually demanded for a lattice action, such as the correct\nclassical continuum limit and the applicability of perturbation theory.\nNevertheless, they still lead to the same universal quantum continuum limit and\nshow excellent scaling behavior. By using the constraint angle action we gain\nnew insight into the Berezinskii-Kosterlitz-Thouless phase transition of the 2d\nXY model. This phase transition is of special interest since it is one of the\nfew examples of a phase transition beyond second order. It is of infinite order\nand therefore an essential phase transition. In particular, we observe an\nexcellent scaling behavior of the helicity modulus, which characterizes this\nphase transition. We also observe that the mechanism of (un)binding\nvortex--anti-vortex pairs follows the usual pattern, although free vortices do\nnot require any energy in the formulation of the 2d XY model using the\nconstraint angle action."
    },
    {
        "anchor": "Geometrical aspects of chiral anomalies in the overlap: The set of one dimensional lowest energy eigenspaces used to construct the\noverlap induces a two form on gauge orbit space which is the locally exact curl\nof Berry's connection. If anomalies do not cancel, examples of two dimensional\nclosed sub-manifolds of orbit space are produced over which the integral of the\nabove two form does not vanish. Based on these observations, a natural\ndefinition of covariant currents is obtained, a simple way to calculate chiral\nanomalies on the lattice is found, and indications for how to construct an\nideal regularization of chiral gauge theories are seen to emerge.",
        "positive": "The Simple Center Projection of SU(2) Gauge Theory: We consider the SU(2) lattice gauge model. We propose a new gauge invariant\ndefinition of center projection, which we call the Simple Center Projection. We\ndemonstrate the center dominance, i.e., the coincidence of the projected\npotential with the full potential up to the mass renormalization term at low\nenergies. We also consider the center vortices and the center monopoles ({\\em\nnexuses}). It turns out that the behavior of such objects qualitatively\ncoincides with the behavior of the vortices and monopoles in the Maximal Center\ngauge. The connection of the condensation of nexuses with the dual\nsuperconductor theory is discussed. Numerically the procedure of extracting the\ncenter vortices proposed in this paper is much simpler than the usual Maximal\nCenter Projection."
    },
    {
        "anchor": "Nf=2+1 QCD thermodynamics with gradient flow using two-loop matching\n  coefficients: We study thermodynamic properties of Nf=2+1 QCD on the lattice adopting\nO(a)-improved Wilson quark action and Iwasaki gauge action. To cope with the\nproblems due to explicit violation of the Poincare and chiral symmetries, we\napply the Small Flow-time eXpansion (SFtX) method based on the gradient flow,\nwhich is a general method to correctly calculate any renormalized observables\non the lattice. In this method, the matching coefficients in front of operators\nin the small flow-time expansion are calculated by perturbation theory. In a\nprevious study using one-loop matching coefficients, we found that the SFtX\nmethod works well for the equation of state, chiral condensates and\nsusceptibilities. In this paper, we study the effect of two-loop matching\ncoefficients by Harlander et al. We also test the influence of the\nrenormalization scale in the SFtX method. We find that, by adopting the mu_0\nrenormalization scale of Harlander et al. instead of the conventional\nmu_d=1/sqrt{8t} scale, the linear behavior at large t is improved so that we\ncan perform the t -> 0 extrapolation of the SFtX method more confidently. In\nthe calculation of the two-loop matching coefficients by Harlander et al., the\nequation of motion for quark fields was used. For the entropy density in which\nthe equation of motion has no effects, we find that the results using the\ntwo-loop coefficients agree well with those using one-loop coefficients. On the\nother hand, for the trace anomaly which is affected by the equation of motion,\nwe find discrepancies between the one- and two-loop results at high\ntemperatures. By comparing the results of one-loop coefficients with and\nwithout using the equation of motion, the main origin of the discrepancies is\nsuggested to be attributed to O((aT)^2)=O(1/N_t^2) discretization errors in the\nequation of motion at N_t =< 10.",
        "positive": "An Efficient Cluster Algorithm for CP(N-1) Models: We construct an efficient cluster algorithm for ferromagnetic SU(N)-symmetric\nquantum spin systems. Such systems provide a new regularization for CP(N-1)\nmodels in the framework of D-theory, which is an alternative non-perturbative\napproach to quantum field theory formulated in terms of discrete quantum\nvariables instead of classical fields. Despite several attempts, no efficient\ncluster algorithm has been constructed for CP(N-1) models in the standard\nformulation of lattice field theory. In fact, there is even a no-go theorem\nthat prevents the construction of an efficient Wolff-type embedding algorithm.\nWe present various simulations for different correlation lengths, couplings and\nlattice sizes. We have simulated correlation lengths up to 250 lattice spacings\non lattices as large as 640x640 and we detect no evidence for critical slowing\ndown."
    },
    {
        "anchor": "Semileptonic form factors of heavy-light mesons from lattice QCD: The form factors for the semileptonic decays of heavy-light pseudoscalar\nmesons of the type $D \\to Ke\\nu$ are studied in quenched lattice QCD at\n$\\beta=6.0$ using Wilson fermions. We explore new numerical techniques for\nimproving the signal and study $O(a)$ corrections using three different lattice\ntranscriptions of the vector current. We present a detailed discussion of the\nrelation of these lattice currents to the continuum vector current and show\nthat the disagreement between the previous results is to a large extent due to\nthe value of $Z_V$ used in the calculations. We also present results for the\ndecay constants of light-light, heavy-light and heavy-heavy mesons.",
        "positive": "Decoupling of Layers in the Three-dimensional Abelian Higgs Model: The Abelian Higgs model with anisotropic couplings in 2+1 dimensions is\nstudied in both the compact and non-compact formulations. Decoupling of the\nspace-like planes takes place in the extreme anisotropic limit, so charged\nparticles and gauge fields are presumably localized within these planes. The\nbehaviour of the model under the influence of an external magnetic field is\nexamined in the compact case and yields further characterization of the phases."
    },
    {
        "anchor": "A calculation of the bulk viscosity in SU(3) gluodynamics: We perform a lattice Monte-Carlo calculation of the trace-anomaly two-point\nfunction at finite temperature in the SU(3) gauge theory. We obtain the\nlong-distance properties of the correlator in the continuum limit and extract\nthe bulk viscosity zeta via a Kubo formula. Unlike the tensor correlator\nrelevant to the shear viscosity, the scalar correlator depends strongly on\ntemperature. If s is the entropy density, we find that zeta/s becomes rapidly\nsmall at high T, zeta/s<0.15 at 1.65T_c and zeta/s<0.015 at 3.2T_c. However\nzeta/s rises dramatically just above T_c, with 0.5<zeta/s<2.0 at 1.02T_c.",
        "positive": "Chiral phase transition in a random matrix model with three flavors: The chiral phase transition in the conventional random matrix model is the\nsecond order in the chiral limit, irrespective of the number of flavors N_f,\nbecause it lacks the U_A(1)-breaking determinant interaction term. Furthermore,\nit predicts an unphysical value of zero for the topological susceptibility at\nfinite temperatures. We propose a new chiral random matrix model which resolves\nthese difficulties by incorporating the determinant interaction term within the\ninstanton gas picture. The model produces a second-order transition for N_f=2\nand a first-order transition for N_f=3, and recovers a physical temperature\ndependence of the topological susceptibility."
    },
    {
        "anchor": "2+1 Flavor Lattice QCD with Luescher's Domain-Decomposed HMC Algorithm: We report on a study of 2+1 flavor lattice QCD with the $O(a)$-improved\nWilson quarks on a $16^3\\times 32$ lattice at the lattice spacing $1/a\\approx\n2$GeV employing Luescher's domain-decomposed HMC(LDDHMC) algorithm. This is\ndedicated to a preliminary study for the PACS-CS project which plans to\ncomplete the Wilson-clover $N_f=2+1$ program lowering the up-down quark masses\nclose to the physical values as much as possible. We focus on three issues: (i)\nhow light quark masses we can reach with LDDHMC, (ii) efficiency of the\nalgorithm compared with the conventional HMC, (iii) parameter choice for the\nproduction runs on PACS-CS.",
        "positive": "A tmQCD mixed-action approach to flavour physics: We discuss a mixed-action approach in which sea quarks are regularised using\nnon-perturbatively ${\\rm O}(a)$ improved Wilson fermions, while a fully-twisted\ntmQCD action is used for valence quarks. In this setup, automatic ${\\rm O}(a)$\nimprovement is preserved for valence observables, apart from small residual\n${\\rm O}(a)$ effects from the sea. A strategy for matching sea and valence is\nset up, and carried out for $N_\\mathrm{f}=2+1$ CLS ensembles with open boundary\nconditions at several simulation points. The scaling of basic light-quark\nobservables such as the pseudoscalar meson decay constant is studied, as well\nas the isospin splitting of pseudoscalar meson masses."
    },
    {
        "anchor": "Sphaleron rate as an inverse problem: a novel lattice approach: We compute the sphaleron rate on the lattice. We adopt a novel strategy based\non the extraction of the spectral density via a modified version of the\nBackus-Gilbert method from finite-lattice-spacing and finite-smoothing-radius\nEuclidean topological charge density correlators. The physical sphaleron rate\nis computed by performing controlled continuum limit and zero-smoothing\nextrapolations both in pure gauge and, for the first time, in full QCD.",
        "positive": "B-meson spectroscopy in HQET at order 1/m: We present a study of the B spectrum performed in the framework of Heavy\nQuark Effective Theory expanded to next-to-leading order in 1/m and\nnon-perturbative in the strong coupling. Our analyses have been performed on\nNf=2 lattice gauge field ensembles corresponding to three different lattice\nspacings and a wide range of pion masses. We obtain the Bs-meson mass and\nhyperfine splittings of the B- and Bs-mesons that are in good agreement with\nthe experimental values and examine the mass difference m_{Bs}-m_B as a further\ncross-check of our previous estimate of the b-quark mass. We also report on the\nmass splitting between the first excited state and the ground state in the B\nand Bs systems."
    },
    {
        "anchor": "Charged pion electric polarizability from lattice QCD: We present a calculation of the charged pion electric polarizability using\nthe background field method. To extract the mass-shift induced by the electric\nfield for the accelerated charged particle we fit the lattice QCD correlators\nusing correlators derived from an effective model. The methodology outlined in\nthis study (boundary conditions, fitting procedure, etc.) is designed to ensure\nthat the results are invariant under gauge transformations of the background\nfield. We apply the method to four $N_f=2$ dynamical ensembles to extract\n$\\alpha_{\\pi^\\pm}$ at pion mass of $315$ MeV.",
        "positive": "New Developments in Lattice QCD: Calculation of Flavor Singlet Nucleon\n  Matrix Elements and Hadron Scattering Lengths: Recent developments in lattice QCD calculation of flavor singlet nucleon\nmatrix elements are reviewed. Substantial sea quark contributions are found in\nthe $\\pi$-$N\\ \\sigma$ term and the quark spin content of the nucleon such that\nthe total magnitude including valence contributions is in reasonable agreement\nwith experiments. Some problems with flavor non-singlet nucleon matrix elements\nare pointed out. Recent work on lattice QCD calculation of hadron scattering\nlength is also discussed."
    },
    {
        "anchor": "SU(3) gauge theory with sextet fermions: SU(3) gauge theory coupled to N_f = 2 fermions in the sextet representation\nis a promising candidate for a technicolor inspired Standard Model extension.\nIn this note the progress in the past few years aimed at understanding the\nnon-perturbative properties of the model is reviewed. The main difficulties\nlying ahead in order to make robust conclusions from lattice simulations are\noutlined.",
        "positive": "Optimal lattice domain-wall fermions: I show that the conventional formulations of lattice domain-wall fermion with\nany finite N_s (in the fifth dimension) do not preserve the chiral symmetry\noptimally and propose a new action which preserves the chiral symmetry\noptimally for any finite N_s."
    },
    {
        "anchor": "Reducing Baryon Noise in Lattice QCD Through Partial Quenching: The study of nuclear physics using lattice QCD is hindered by an\nexponentially large signal-to-noise problem which is conventionally alleviated\nby raising the quark masses to unphysically high values. We propose a novel\nform of partial quenching for calculations involving nucleons in which the sea\nquark masses are taken to be smaller than the valence quark masses. It is shown\nthat lowering the sea quark masses toward their physical values actually\nimproves signal-to-noise. An optimized approach to the physical point in the\n(m_s, m_v) plane is proposed, with a full analysis of the cost benefit.\nImprovements in computing time of ~ 10^(2(A-1)), where A is the number of\nnucleons in the system, are shown to be possible.",
        "positive": "A different kind of string: In U(1) lattice gauge theory in three spacetime dimensions, the problem of\nconfinement can be studied analytically in a semi-classical approach, in terms\nof a gas of monopoles with Coulomb-like interactions. In addition, this theory\ncan be mapped to a spin model via an exact duality transformation, which allows\none to perform high-precision numerical studies of the confining potential.\nTaking advantage of these properties, we carried out an accurate investigation\nof the effective string describing the low-energy properties of flux tubes in\nthis confining gauge theory. We found striking deviations from the expected\nNambu-Goto-like behavior, and, for the first time, evidence for contributions\nthat can be described by a term proportional to the extrinsic curvature of the\neffective string worldsheet. Such term is allowed by Lorentz invariance, and\nits presence in the infrared regime of the U(1) model was indeed predicted by\nPolyakov several years ago. Our results show that this term scales as expected\naccording to Polyakov's solution, and becomes the dominant contribution to the\neffective string action in the continuum limit. We also demonstrate\nanalytically that the corrections to the confining potential induced by the\nextrinsic curvature term can be related to the partition function of the\nmassive perturbation of a c=1 bosonic conformal field theory. The implications\nof our results for SU(N) Yang-Mills theories in three and in four spacetime\ndimensions are discussed."
    },
    {
        "anchor": "A Quasi-staggered Scheme on Lattice: Utilizing a picture of string and string spinors, we show a simpler version\nof staggered action. The advantage of this action is that in this action there\nalways exist pair of quarks with different masses.",
        "positive": "Instantons and chiral symmetry breaking in SU(N) gauge theories: We address the question of whether the low modes of the Dirac operator are\ncaused by topological objects such as instantons in SU(N) gauge theories. We\nstudy the pseudo-scalar density of these modes, finding the size distributions\nof the instantons, and comparing it with the underlying gauge field. We find\nthat, although the near-zero modes of the Dirac operator depend on topology for\nall N, their small instanton content decreases as N increases."
    },
    {
        "anchor": "Debye mass from domainwalls and dimensionally reduced phase diagram: To measure the Debye mass in dimensionally reduced QCD for $N_c\\le 3$ we\nreplace in the correlator of two Polyakov loops one of the loops by a wall\ntriggered by a dimensionally reduced twist. The phase diagram for $N_c=3$ has\nR-parity broken in part of the Higgs phase.",
        "positive": "$B$-meson semileptonic decays with highly improved staggered quarks: We present an update of the Fermilab Lattice and MILC Collaborations project\nto compute the form factors for semileptonic $B_{(s)}$-meson decays. Our\ncalculation uses the highly improved staggered quark (HISQ) action for sea and\nvalence quarks, and ensembles with up, down, strange, and charm quarks in the\nsea. Using a highly improved action with the MILC Collaboration's gauge\nensembles with lattice spacings down to $a\\approx0.03$ fm, allows the heavy\nvalence quarks to be treated with the same discretization as the light and\nstrange quarks. This unified treatment of the valence quarks allows for\nabsolutely normalized vector currents, bypassing the need for perturbative\nmatching, which has been a source of uncertainty in previous calculations of\n$B$-meson decay form factors by our collaboration. All preliminary form-factor\nresults are blinded."
    },
    {
        "anchor": "On the foundations of partially quenched chiral perturbation theory: It has been widely assumed that partially quenched chiral perturbation theory\nis the correct low-energy effective theory for partially quenched QCD. Here we\npresent arguments supporting this assumption. First, we show that, for\npartially quenched QCD with staggered quarks, a transfer matrix can be\nconstructed. This transfer matrix is not Hermitian, but it is bounded, and it\ncan be used to construct correlation functions in the usual way. Combining\nthese observations with an extension of the Vafa--Witten theorem to the\npartially quenched theory allows us to argue that the partially quenched theory\nsatisfies the cluster property. By extending Leutwyler's analysis of the\nunquenched case to the partially quenched theory, we then conclude that the\nexistence and properties of the transfer matrix as well as clustering are\nsufficient for partially quenched chiral perturbation theory to be the correct\nlow-energy theory for partially quenched QCD.",
        "positive": "Compact fields and mass generation: It is shown that the free propagator of an angular, i.e. compact, field with\nzero lagrangian mass acquires a nonzero propagator mass $\\omega$ (`kinematical'\nmass generation). To demonstrate this effect the free propagator of the\ngoldstone boson in an O(2) model with spontaneous symmetry breaking is\ncalculated. It is shown that this propagator is massive, the mass $\\omega$\nbeing a function of the scalar `condensate' ${\\bar\\phi}$."
    },
    {
        "anchor": "Thermodynamics of Lattice QCD with 2 Quark Flavours: Chiral Symmetry and\n  Topology: We have studied the restoration of chiral symmetry in lattice QCD at the\nfinite temperature transition from hadronic matter to a quark-gluon plasma. By\nmeasuring the screening masses of flavour singlet and non-singlet meson\nexcitations, we have seen evidence that, although flavour chiral symmetry is\nrestored at this transition, flavour singlet (U(1)) axial symmetry is not. We\nconclude that this indicates that instantons continue to play an important role\nin the quark-gluon plasma phase.",
        "positive": "A Lecture on Chiral Fermions: This is an informal and approximate transcription of a talk presented at the\nDESY workshop, September 27--29, 1995. The basic message is that real and long\noverdue progress is taking place on the problem of regulating\nnon--perturbatively chiral gauge theories. Several approaches are reviewed with\nemphasis on the overlap and some of the questions raised about it. No claim for\ncompleteness or objectivity is made."
    },
    {
        "anchor": "Landau Ginzberg model and deconfinement transition for extended SU(2)\n  action: We compute the effective action in terms of the Polyakov loop for the\n3-dimensional pure fundamental-adjoint SU(2) lattice gauge theory at non-zero\ntemperatures using the strong coupling expansion. In the extended coupling\nplane we show the existence of a tricritical point where the nature of the\ndeconfinement transition undergoes a change from second to first order. The\nresulting phase structure is in excellent agreement with the Monte Carlo\nresults both in the fundamental and adjoint directions. The possible\nconsequences of our results on universality are discussed.",
        "positive": "P-Wave Two-Particle Bound and Scattering States in a Finite Volume\n  including QED: The mass shifts for two-fermion bound and scattering P-wave states subject to\nthe long-range interactions due to QED in the non-relativistic regime are\nderived. Introducing a short range force coupling the spinless fermions to one\nunit of angular momentum in the framework of pionless EFT, we first calculate\nboth perturbatively and non-perturbatively the Coulomb corrections to\nfermion-fermion scattering in the continuum and infinite volume context.\nMotivated by the research on particle-antiparticle bound states, we extend the\nresults to fermions of identical mass and opposite charge. Second, we transpose\nthe system onto a cubic lattice with periodic boundary conditions and we\ncalculate the finite volume corrections to the energy of the lowest bound and\nunbound $T_1^{\\pm}$ eigenstates. In particular, power law corrections\nproportional to the fine structure constant and resembling the recent results\nfor S-wave states are found. Higher order contributions in $\\alpha$ are\nneglected, since the gapped nature of the momentum operator in the lattice\nenvironnement allows for a perturbative treatment of the QED interactions."
    },
    {
        "anchor": "Light hadron spectrum using an O(a)-improved Wilson action with two\n  dynamical quark flavours: I present results of recent work for the UKQCD Collaboration on the light\nhadron spectrum using a non-perturbatively O(a)-improved Wilson action with two\ndegenerate flavours of dynamical quarks on a 16^3x32 lattice. Values of the\nbare gauge coupling and bare dynamical quark mass were chosen to keep the\nlattice spacing fixed at two distinct values in physical units as determined\nthrough the Sommer scale parameter, r0. I also include results for a quenched\nensemble with a lattice spacing matching one of these dynamical sets and\nresults from an exploratory run at lighter bare quark mass.",
        "positive": "Quark Mass Dependence of Nucleon Properties and Extrapolation from\n  Lattice QCD: We summarize developments concerning the quark mass dependence of nucleon\nmagnetic moments and the axial-vector coupling constant g_A. The aim is to\nexplore the feasibility of chiral effective field theory methods for the\nextrapolation of lattice QCD results, from the relatively large quark masses\nthat can be handled in such computations down to the physically relevant range."
    },
    {
        "anchor": "Tuning the generalized Hybrid Monte Carlo algorithm: We discuss the analytic computation of autocorrelation functions for the\ngeneralized Hybrid Monte Carlo algorithm applied to free field theory and\ncompare the results with numerical results for the $O(4)$ spin model in two\ndimensions. We explain how the dynamical critical exponent $z$ for some\noperators may be reduced from two to one by tuning the amount of randomness\nintroduced by the updating procedure, and why critical slowing down is not a\nproblem for other operators.",
        "positive": "Electric Dipole Moment Results from lattice QCD: We utilize the gradient flow to define and calculate electric dipole moments\ninduced by the strong QCD $\\theta$-term and the dimension-6 Weinberg operator.\nThe gradient flow is a promising tool to simplify the renormalization pattern\nof local operators. The results of the nucleon electric dipole moments are\ncalculated on PACS-CS gauge fields (available from the ILDG) using $N_{f}=2+1$,\nof discrete size $32^{3}\\times 64$ and spacing $a \\simeq 0.09$ fm. These gauge\nfields use a renormalization-group improved gauge action and a\nnon-perturbatively $O(a)$ improved clover quark action at $\\beta = 1.90$, with\n$c_{SW} = 1.715$. The calculation is performed at pion masses of $m_{\\pi}\n\\simeq 411,701$ MeV."
    },
    {
        "anchor": "Comment on \"Are two nucleons bound in lattice QCD for heavy quark\n  masses? - Sanity check with L\u00fcscher's finite volume formula -\": In this comment, we address a number of erroneous discussions and conclusions\npresented in a recent preprint by the HALQCD collaboration, arXiv:1703.07210.\nIn particular, we demonstrate that lattice QCD determinations of bound states\nat quark masses corresponding to a pion mass of $m_\\pi = 806$ MeV are robust,\nand that the phases shifts extracted by the NPLQCD collaboration for these\nsystems pass all of the 'sanity checks' introduced in arXiv:1703.07210.",
        "positive": "$3$--Dimensional Approach to Hot Electroweak Matter for $M_{Higgs} \\leq\n  70$ GeV: We study the electroweak phase transition by lattice simulations of an\neffective 3-dimensional theory, for a Higgs mass of about $70$ GeV. Exploiting\na variant of the equal weight criterion of phase equilibrium, we obtain\ntransition temperature, latent heat and surface tension and compare with $M_H\n\\approx 35$ GeV. For the symmetric phase, bound state masses and the static\nforce are determined and compared with results for pure $SU(2)$ theory."
    },
    {
        "anchor": "Methods for high-precision determinations of radiative-leptonic decay\n  form factors using lattice QCD: We present a study of lattice-QCD methods to determine the relevant hadronic\nform factors for radiative leptonic decays of pseudoscalar mesons. We provide\nnumerical results for $D_s^+ \\to \\ell^+ \\nu \\gamma$. Our calculation is\nperformed using a domain-wall action for all quark flavors and on a single\nRBC/UKQCD lattice gauge-field ensemble. The first part of the study is how to\nbest control two sources of systematic error inherent in the calculation,\nspecifically the unwanted excited states created by the meson interpolating\nfield, and unwanted exponentials in the sum over intermediate states. Using a\n3d sequential propagator allows for better control over unwanted exponentials\nfrom intermediate states, while using a 4d sequential propagator allows for\nbetter control over excited states. We perform individual analyses of the 3d\nand 4d methods as well as a combined analysis using both methods, and find that\nthe 3d sequential propagator offers good control over both sources of\nsystematic uncertainties for the smallest number of propagator solves. From\nthere, we further improve the use of a 3d sequential propagator by employing an\ninfinite-volume approximation method, which allows us to calculate the relevant\nform factors over the entire allowed range of photon energies. We then study\nimprovements gained by performing the calculation using a different three-point\nfunction, using ratios of three-point functions, averaging over positive and\nnegative photon momentum, and using an improved method for extracting the\nstructure-dependent part of the axial form factor. The optimal combination of\nmethods yields results for the $D_s^+ \\to \\ell^+ \\nu \\gamma$\nstructure-dependent vector and axial form factors in the entire kinematic range\nwith statistical plus fitting uncertainties of order 5%, using 25 gauge\nconfigurations with 64 samples per configuration.",
        "positive": "Minimizing storage in implementations of the overlap lattice-Dirac\n  operator: The overlap lattice-Dirac operator contains the sign function $\\epsilon (H)$.\nRecent practical implementations replace $\\epsilon (H)$ by a ratio of\npolynomials, $H P_n (H^2)/Q_n (H^2)$, and require storage of $2n+2$ large\nvectors. Here I show that one can use only 4 large vectors at the cost of\nexecuting the core conjugate algorithm twice. The slow-down might be less than\nby a factor of 2, depending on the architecture of the computer one uses."
    },
    {
        "anchor": "Energy-momentum tensor correlators and spectral functions: We calculate the thermal Euclidean correlators and the spectral functions of\nthe energy-momentum tensor for pure gauge theories, including at non-zero\nspatial momentum, at leading order in perturbation theory. Our goal is to\nimprove the extraction of transport properties from Euclidean correlators that\nare computable in lattice QCD. Based on our results and the predictions of\nhydrodynamics for the structure of the spectral functions at low frequencies,\nwe show that the shear and bulk viscosities can advantageously be extracted\nfrom the Euclidean correlators of the conserved charges, energy and momentum,\nat small but non-vanishing spatial momentum. The spectral functions in these\nchannels are free of the ultraviolet $\\omega^4$ term which represents a large\nbackground to the thermal physics encoded in the correlators of the fluxes.",
        "positive": "Quantum field-theoretic machine learning: We derive machine learning algorithms from discretized Euclidean field\ntheories, making inference and learning possible within dynamics described by\nquantum field theory. Specifically, we demonstrate that the $\\phi^{4}$ scalar\nfield theory satisfies the Hammersley-Clifford theorem, therefore recasting it\nas a machine learning algorithm within the mathematically rigorous framework of\nMarkov random fields. We illustrate the concepts by minimizing an asymmetric\ndistance between the probability distribution of the $\\phi^{4}$ theory and that\nof target distributions, by quantifying the overlap of statistical ensembles\nbetween probability distributions and through reweighting to complex-valued\nactions with longer-range interactions. Neural network architectures are\nadditionally derived from the $\\phi^{4}$ theory which can be viewed as\ngeneralizations of conventional neural networks and applications are presented.\nWe conclude by discussing how the proposal opens up a new research avenue, that\nof developing a mathematical and computational framework of machine learning\nwithin quantum field theory."
    },
    {
        "anchor": "Good and bad diquark properties and spatial correlations in lattice QCD: We study good, bad and not-even-bad diquarks on the lattice in a\ngauge-invariant formalism in full QCD. We establish their spectral masses with\nshort extrapolations to the physical point, observing agreement with\nphenomenological expectations. We find that only the good diquark has\nattractive quark-quark spatial correlations, with spherical shape and size\n$\\sim0.6$ fm. Our results provide quantitative support for modelling the\nlow-lying baryon spectrum using good light diquark effective degrees of\nfreedom.",
        "positive": "The upper right corner of the Columbia plot with staggered fermions: QCD with heavy dynamical quarks exhibits a first order thermal transition\nwhich is driven by the spontaneous breaking of the global $\\mathcal{Z}_3$\ncenter symmetry. Decreasing the quark masses weakens the transition until the\ncorresponding latent heat vanishes at the critical mass. We explore the heavy\nmass region with three flavors of staggered quarks and analyze the Polyakov\nloop and its moments in a finite volume scaling study. We calculate the heavy\ncritical mass in the three flavor theory in the infinite volume limit for\n$N_t=8$."
    },
    {
        "anchor": "Propagators and topology: Two popular perspectives on the non-perturbative domain of Yang-Mills\ntheories are either in terms of the gluons themselves or in terms of collective\ngluonic excitations, i.e. topological excitations. If both views are correct,\nthen they are only two different representations of the same underlying\nphysics. One possibility to investigate this connection is by the determination\nof gluon correlation functions in topological background fields, as created by\nthe smearing of lattice configurations. This is performed here for the minimal\nLandau gauge gluon propagator, ghost propagator, and running coupling, both in\nmomentum and position space for SU(2) Yang-Mills theory. The results show that\nthe salient low-momentum features of the propagators are qualitatively retained\nunder smearing at sufficiently small momenta, in agreement with an equivalence\nof both perspectives. However, the mid-momentum behavior is significantly\naffected. These results are also relevant for the construction of truncations\nin functional methods, as they provide hints on necessary properties to be\nretained in truncations.",
        "positive": "Critical Exponents of the Classical Heisenberg Ferromagnet: In a recent letter, R.G. Brown and M. Ciftan (Phys. Rev. Lett. 76, 1352,\n1996) reported high precision Monte Carlo (MC) estimates of the static critical\nexponents of the classical 3D Heisenberg model, which stand in sharp contrast\nto values obtained by four independent approaches, namely by other recent high\nstatistics MC simulations, high-temperature series analyses, field theoretical\nmethods, and experimental studies. In reply to the above cited work we\nsubmitted this paper as a comment to Phys. Rev. Lett."
    },
    {
        "anchor": "Baryon spectrum using Nf=2+1+1 ensembles of twisted mass fermions: We present results on the masses of the low-lying baryons using ten ensembles\nof gauge configurations with $N_f =2+1+1$ dynamical twisted mass fermions, at\nthree values of the lattice spacing, spanning a pion mass range from about 210\nMeV to about 430 MeV. The strange and charm quark masses are tuned to\napproximately their physical values. We examine isospin symmetry breaking\neffects on the baryon mass and the dependence on the lattice spacing. After\ntaking the continuum limit we use chiral perturbation theory to extrapolate to\nthe physical vlaue of the pion mass for all forty baryons. We provide\npredictions for the masses of doubly and triply charmed baryons that have not\nyet been measured experimentally.",
        "positive": "Lattice study of static quark-antiquark interactions in dense quark\n  matter: In this paper we study the interactions among a static quark-antiquark pair\nin the presence of dense two-color quark matter with lattice simulation. To\nthis end we compute Polyakov line correlation functions and determine the\nrenormalized color averaged, color singlet and color triplet grand potentials.\nThe color singlet grand potential allows us to elucidate the number of quarks\ninduced by a static quark antiquark source, as well as the internal energy of\nsuch a pair in dense quark matter. We furthermore determine the screening\nlength, which in the confinement phase is synonymous with the string breaking\ndistance. The screening length is a decreasing function of baryon density, due\nto the possibility to break the interquark string via a scalar diquark\ncondensate at high density. We also study the large distance properties of the\ncolor singlet grand potential in a dense medium and find that it is well\ndescribed by a simple Debye screening formula, parameterized by a Debye mass\nand an effective coupling constant. The latter is of order of unity, i.e. even\nat large density two-color quark matter is a strongly correlated system."
    },
    {
        "anchor": "Bottomonia screening masses from $2 + 1$ flavor QCD: The sequential melting of the bottomonium states is one of the important\nsignals for the existence of a quark gluon plasma. The study of bottomonia\nspectral functions on the lattice is a difficult task for many reasons.\nCalculations based on NRQCD, that are commonly used for such purpose, are not\napplicable at high temperatures. In this work we propose a new method to study\nthis problem by calculating the spatial screening masses of bottomonium states.\nWe calculate the spatial meson correlators and extract the screening masses for\nmesons in different quantum channels using highly improved staggered quark\n(HISQ) action for bottom quarks and dynamical $2+1$ flavor QCD HISQ gauge\nconfigurations. The typical lattices we choose are of size $N_s^3 \\times\nN_\\tau$ where $N_s=4 N_\\tau$ and $N_\\tau=8, 10, 12$. We consider the\ntemperature range $T = 300$-$1000$ MeV. We show that for $T > 500$ MeV the\ntemperature dependence of the screening masses of the ground state bottomonia\nare compatible with the expectations based on uncorrelated quark anti-quark\npairs.",
        "positive": "Semileptonic Kaon Decay in Staggered Chiral Perturbation Theory: The determination of $\\vert V_{us}\\vert$ from kaon semileptonic decays\nrequires the value of the form factor $f_+(q^2=0)$, which can be calculated\nprecisely on the lattice. We provide the one-loop partially quenched staggered\nchiral perturbation theory expressions that may be employed to analyze\nstaggered simulations of $f_+(q^2)$ with three light flavors. We consider both\nthe case of a mixed action, where the valence and sea sectors have different\nstaggered actions, and the standard case where these actions are the same. The\nmomentum transfer $q^2$ of the form factor is allowed to have an arbitrary\nvalue. We give results for the generic situation where the $u$, $d$, and $s$\nquark masses are all different, $N_f=1+1+1$, and for the isospin limit,\n$N_f=2+1$. The expression we obtain for $f_+(q^2)$ is independent of the mass\nof the (valence) spectator quark. In the limit of vanishing lattice spacing,\nour results reduce to the one-loop continuum partially quenched expression for\n$f_+(q^2)$, which has not previously been reported in the literature for the\n$N_f=1+1+1$ case. Our expressions have already been used in staggered lattice\nanalyses of $f_+(0)$, and should prove useful in future calculations as well."
    },
    {
        "anchor": "Rho resonance, timelike pion form factor, and implications for lattice\n  studies of the hadronic vacuum polarisation: We study isospin-1 P-wave $\\pi\\pi$ scattering in lattice QCD with two\nflavours of O($a$) improved Wilson fermions. For pion masses ranging from\n$m_\\pi=265$ MeV to $m_\\pi=437$ MeV, we determine the energy spectrum in the\ncentre-of-mass frame and in three moving frames. We obtain the scattering phase\nshifts using L\\\"uscher's finite-volume quantisation condition. Fitting the\ndependence of the phase shifts on the scattering momentum to a Breit-Wigner\nform allows us to determine the resonance parameters $m_\\rho$ and\n$g_{\\rho\\pi\\pi}$. By combining the scattering phase shifts with the decay\nmatrix element of the vector current, we calculate the timelike pion form\nfactor, $F_\\pi$, and compare the results to the Gounaris-Sakurai representation\nof the form factor in terms of the resonance parameters. In addition, we fit\nour data for the form factor to the functional form suggested by the Omn\\`es\nrepresentation, which allows for the extraction of the charge radius of the\npion. As a further application, we discuss the long-distance behaviour of the\nvector correlator, which is dominated by the two-pion channel. We reconstruct\nthe long-distance part in two ways: one based on the finite-volume energies and\nmatrix elements and the other based on $F_\\pi$. It is shown that this part can\nbe accurately constrained using the reconstructions, which has important\nconsequences for lattice calculations of the hadronic vacuum polarisation\ncontribution to the muon anomalous magnetic moment.",
        "positive": "Universal Aspects of Deconfinement: Interfaces, Flux Tubes and\n  Self-Duality in 2+1 Dimensions: We study center vortex free energies and 't Hooft's electric fluxes on the\nlattice in 2+1 dimensions, where SU(2) for example, is in the universality\nclass of the 2d Ising model. This places a wealth of exact results at our\nfingertips. In particular, spacelike center vortices in SU(2) near criticality\ncorrespond to spin interfaces in the 2d Ising model, whose universal scaling\nfunctions are known exactly. We exploit this to locate the deconfinement\ntransition with unprecedented precision and subsequently for a finite size\nscaling analysis, where the self-duality of the $2d$ spin model is reflected in\na duality between the spacelike vortices and confining electric fluxes. The\ncorresponding relation between the string tension and its dual in the high\ntemperature phase is arguably the simplest example of a universal amplitude\nratio. Around the transition, both can be efficiently extracted from the exact\nresults with a global one-parameter fit which allows straightforward continuum\nextrapolation."
    },
    {
        "anchor": "Lattice Field Theory with the Sign Problem and the Maximum Entropy\n  Method: Although numerical simulation in lattice field theory is one of the most\neffective tools to study non-perturbative properties of field theories, it\nfaces serious obstacles coming from the sign problem in some theories such as\nfinite density QCD and lattice field theory with the $\\theta$ term. We\nreconsider this problem from the point of view of the maximum entropy method.",
        "positive": "Understanding the U(1) problem through dyon configuration in the Abelian\n  projection: We give a short review of the recently obtained result that the magnetic\nmonopole promoted to the dyon due to the vacuum angle $\\theta$ resolves the\nU(1) problem in the sense that the dyon obtained in this way gives a dominant\ncontribution to the topological susceptibility"
    },
    {
        "anchor": "Model independent approach to studies of the confining dual Abrikosov\n  vortex in SU(2) lattice gauge theory: We address the problem of determining the type I, type II or borderline dual\nsuperconductor behavior in maximal Abelian gauge SU(2) through the study of the\ndual Abrikosov vortex. We find that significant electric currents in the\nsimulation data call into question the use of the dual Ginzburg Landau Higgs\nmodel in interpreting the data. Further, two definitions of the penetration\ndepth parameter take two different values. The splitting of this parameter into\ntwo is intricately connected to the existence of electric currents. It is\nimportant in our approach that we employ definitions of flux and electric and\nmagnetic currents that respect Maxwell equations exactly for lattice averages\nindependent of lattice spacings. Applied to specific Wilson loop sizes, our\nconclusions differ from those that use the dual GLH model.",
        "positive": "Flavor symmetry breaking in lattice QCD with a mixed action: We study the phase structure of mixed-action QCD with two Wilson sea quarks\nand any number of chiral valence quarks (and ghosts), starting from the chiral\nlagrangian. A priori, the effective theory allows for a rich phase structure,\nincluding a phase with a condensate made of sea and valence quarks. In such a\nphase, mass eigenstates would become admixtures of sea and valence fields, and\npure-sea correlation functions would depend on the parameters of the valence\nsector, in contradiction with the actual setup of mixed-action simulations.\nUsing that the spectrum of the chiral Dirac operator has a gap for nonzero\nquark mass we prove that spontaneous symmetry breaking of the flavor symmetries\ncan only occur within the sea sector. This rules out a mixed condensate, and\nimplies restrictions on the low-energy constants of the effective theory."
    },
    {
        "anchor": "QCD dynamics in a constant chromomagnetic field: We investigate the phase transition in full QCD with two flavors of staggered\nfermions in presence of a constant abelian chromomagnetic field. We find that\nthe critical temperature depends on the strength of the chromomagnetic field\nand that the deconfined phase extends to very low temperatures for strong\nenough fields. As in the case of zero external field, a single transition is\ndetected, within statistical uncertainties, where both deconfinement and chiral\nsymmetry restoration take place. We also find that the chiral condensate\nincreases with the strength of the chromomagnetic field.",
        "positive": "The order of the quantum chromodynamics transition predicted by the\n  standard model of particle physics: We determine the nature of the QCD transition using lattice calculations for\nphysical quark masses. Susceptibilities are extrapolated to vanishing lattice\nspacing for three physical volumes, the smallest and largest of which differ by\na factor of five. This ensures that a true transition should result in a\ndramatic increase of the susceptibilities.No such behaviour is observed: our\nfinite-size scaling analysis shows that the finite-temperature QCD transition\nin the hot early Universe was not a real phase transition, but an analytic\ncrossover (involving a rapid change, as opposed to a jump, as the temperature\nvaried). As such, it will be difficult to find experimental evidence of this\ntransition from astronomical observations."
    },
    {
        "anchor": "The confining color field in SU(3) gauge theory: We extend a previous numerical study of SU(3) Yang-Mills theory in which we\nmeasured the spatial distribution of all components of the color fields\nsurrounding a static quark-antiquark pair for a wide range of quark-antiquark\nseparations, and provided evidence that the simulated gauge invariant\nchromoelectric field can be separated into a Coulomb-like 'perturbative' field\nand a 'non-perturbative' field, identified as the confining part of the SU(3)\nflux tube field. In this paper we hypothesize that the fluctuating color fields\nnot measured in our simulations do not contribute to the string tension. Under\nthis assumption the string tension is determined by the color fields we\nmeasure, which form a tensor $F_{\\mu \\nu}$ pointing in a single direction in\ncolor space. We call this the Maxwell mechanism of confinement. We provide an\nadditional procedure to isolate the non-perturbative (confining) field. We then\nextract the string tension from a stress energy-momentum tensor $T_{\\mu \\nu}$\nhaving the Maxwell form, constructed from the non-perturbative part of the\ntensor $F_{\\mu \\nu}$ obtained from our simulations. To test our hypothesis we\ncalculate the string tension from our simulations of the color fields for ten\nvalues of the quark-antiquark separation ranging from 0.37 fm to 1.2 fm. We\nalso calculate the spatial distributions of the energy-momentum tensor $T_{\\mu\n\\nu}$ surrounding static quarks for this range of separations, and we compare\nthese distributions with those obtained from direct simulations of the\nenergy-momentum tensor in SU(3) Yang-Mills theory.",
        "positive": "Hausdorff dimension of fermions on a random lattice: Geometric properties of lattice quantum gravity in two dimensions are studied\nnumerically via Monte Carlo on Euclidean Dynamical Triangulations. A new\ncomputational method is proposed to simulate gravity coupled with fermions,\nwhich allows the study of interacting theories on a lattice, such as\nnon-Riemannian gravity models. This was tested on Majorana spinors, where we\nobtained a Hausdorff dimension dW = 4.22 +/- 0.03, consistent with the bounds\nfrom the literature 4.19 < dH < 4.21."
    },
    {
        "anchor": "Multi-Particle Baryon Spectroscopy: In Nature the excited states of the hadron spectrum appear as resonances.\nConsequently, there has been significant interest in studying the excited\nbaryon spectrum using lattice QCD. With this in mind we perform spectroscopic\ncalculations with five-quark interpolating fields. Stochastic estimation\ntechniques are used in order to calculate the loop propagators, with dilution\nin spin, colour and time implemented as a means of variance reduction. We\npresent effective mass plots extracted from these five-quark interpolators, and\nexamine the contributions from fully-connected and loop-containing pieces of\nthe correlation function, keeping in mind their use in future corre- lation\nmatrix studies.",
        "positive": "Four-dimensional pure compact U(1) gauge theory on a spherical lattice: We investigate the confinement-Coulomb phase transition in the\nfour-dimensional (4D) pure compact U(1) gauge theory on spherical lattices. The\naction contains the Wilson coupling beta and the double charge coupling gamma.\nThe lattice is obtained from the 4D surface of the 5D cubic lattice by its\nradial projection onto a 4D sphere, and made homogeneous by means of\nappropriate weight factors for individual plaquette contributions to the\naction. On such lattices the two-state signal, impeding the studies of this\ntheory on toroidal lattices, is absent for gamma le 0. Furthermore, here a\nconsistent finite-size scaling behavior of several bulk observables is found,\nwith the correlation length exponent nu in the range nu = 0.35 - 40. These\nobservables include Fisher zeros, specific-heat and cumulant extrema as well as\npseudocritical values of beta at fixed gamma. The most reliable determination\nof nu by means of the Fisher zeros gives nu = 0.365(8). The phase transition at\ngamma le 0 is thus very probably of 2nd order and belongs to the universality\nclass of a non-Gaussian fixed point."
    },
    {
        "anchor": "The spectral reconstruction of inclusive rates: A recently re-discovered variant of the Backus-Gilbert algorithm for spectral\nreconstruction enables the controlled determination of smeared spectral\ndensities from lattice field theory correlation functions. A particular\nadvantage of this approach is the \\emph{a priori} specification of the kernel\nwith which the underlying spectral density is smeared, allowing for variation\nof its peak position, smearing width, and functional form. If the unsmeared\nspectral density is sufficiently smooth in the neighborhood of a particular\nenergy, it can be obtained from an extrapolation to zero smearing-kernel width\nat fixed peak position. A natural application for this approach is scattering\nprocesses summed over all hadronic final states. As a proof-of-principle test,\nan inclusive rate is computed in the two-dimensional O(3) sigma model from a\ntwo-point correlation function of conserved currents. The results at finite and\nzero smearing radius are in good agreement with the known analytic form up to\nenergies at which 40-particle states contribute, and are sensitive to the\n4-particle contribution to the inclusive rate. The straight-forward adaptation\nto compute the $R$-ratio in lattice QCD from two-point functions of the\nelectromagnetic current is briefly discussed.",
        "positive": "Overview of the QCD phase diagram -- Recent progress from the lattice: In recent years there has been much progress on the investigation of the QCD\nphase diagram with lattice QCD simulations. In this review I focus on the\ndevelopments in the last two years. Especially the addition of external\ninfluences or new parameter ranges yield an increasing number of interesting\nresults. I discuss the progress for small, finite densities from both\nanalytical continuation and Complex Langevin simulations, for heavy quark bound\nstates (quarkonium), the dependence on the quark masses (Columbia plot) and the\ninfluence of a magnetic field. Many of these conditions are relevant for the\nunderstanding of both the QCD transition in the early universe and heavy ion\ncollision experiments which are conducted for example at the LHC and RHIC."
    },
    {
        "anchor": "$B_K$ with improved staggered fermions: analysis using SU(3) staggered\n  chiral perturbation theory: We report updated results for $B_K$ using HYP-smeared staggered valence\nquarks on MILC asqtad lattices based on an analysis using SU(3) staggered\nchiral perturbation theory. The most important new feature of our data sample\nis the inclusion of a fourth (\"ultrafine\") lattice spacing. This improves the\ncontrol over the continuum extrapolation and errors due our use of one-loop\nperturbative matching. We present a complete updated error budget, which leads\nto $B_K(\\text{NDR}, \\mu = 2 \\text{GeV}) = 0.5309 \\pm 0.0051 \\pm 0.0424$ and\n$\\hat{B}_K = B_K(\\text{RGI}) = 0.727 \\pm 0.07 \\pm 0.058$. The results of the\nSU(3) analysis are inferior to those based on SU(2) staggered chiral\nperturbation theory, primarily because of the dependence on the Bayesian priors\nwe use in the SU(3) fits.",
        "positive": "Staggered eigenvalue mimicry: We study the infrared part of the spectrum for UV-filtered staggered Dirac\noperators and compare them to the overlap counterpart. With sufficient\nfiltering and at small enough lattice spacing the staggered spectra manage to\n``mimic'' the overlap version. They show a 4-fold near-degeneracy, and a clear\nseparation between would-be zero modes and non-zero modes. This suggests an\napproximate index theorem for filtered staggered fermions and a correct\nsensitivity to the topology of QCD. Moreover, it supports square-rooting the\nstaggered determinant to obtain dynamical ensembles with $N_f=2$."
    },
    {
        "anchor": "Lattice QCD at non-zero baryon number: We discuss the quenched limit of lattice QCD at non-zero baryon number\ndensity. We find evidence for a mixed phase that becomes broader with\nincreasing baryon number. Although the action is explicitly Z(3) symmetric the\nPolyakov loop expectation value becomes non-zero already in the low temperature\nphase. It indicates that the heavy quark potential stays finite at large\ndistances, i.e. the string between static quarks breaks at non-zero baryon\nnumber density already in the hadronic phase. This behaviour is validated by\ncalculating the heavy quark potential using Polyakov loop correlations.",
        "positive": "A Regularization of Quantum Gravity: We re-examine results of the Liouville theory and provide arguments that a\n{\\it negative} bare cosmological constant is essential to define\ntwo-dimensional quantum gravity. From this we are naturally led to a\nregularization of quantum gravity within the Regge approach such that it is\ndescribed by small fluctuations around equilateral triangles, whose average\nlink length approaches zero in the continuum limit. We investigate a model\nbased on this idea numerically and present evidence for the desired long-range\ncorrelations. Interestingly, the approach might generalize to higher\ndimensions. The picture of an inflated balloon, which is often used to\ndemonstrate the properties of an expanding classical universe, seems to be\nvaluable to understand quantum gravity as well."
    },
    {
        "anchor": "Chiral perturbation theory and nucleon-pion-state contaminations in\n  lattice QCD: Multi-particle states with additional pions are expected to be a\nnon-negligible source of excited-state contamination in lattice simulations at\nthe physical point. It is shown that baryon chiral perturbation theory can be\nemployed to calculate the contamination due to two-particle nucleon-pion states\nin various nucleon observables. Leading order results are presented for the\nnucleon axial, tensor and scalar charge and three Mellin moments of parton\ndistribution functions (quark momentum fraction, helicity and transversity\nmoment). Taking into account phenomenological results for the charges and\nmoments the impact of the nucleon-pion-states on lattice estimates for these\nobservables can be estimated. The nucleon-pion-state contribution results in an\noverestimation of all charges and moments obtained with the plateau method. The\noverestimation is at the 5-10% level for source-sink separations of about 2 fm.\nThe source-sink separations accessible in contemporary lattice simulations are\nfound to be too small for chiral perturbation theory to be directly applicable.",
        "positive": "More on volume dependence of spectral weight function: Spectral weight functions are easily obtained from two-point correlation\nfunctions and they might be used to distinguish single-particle from\nmulti-particle states in a finite-volume lattice calculation, a problem crucial\nfor many lattice QCD simulations. In previous studies, it is shown that the\nspectral weight function for a broad resonance shares the typical volume\ndependence of a two-particle scattering state i.e. proportional to $1/L^3$ in a\nlarge cubic box of size $L$ while the narrow resonance case requires further\ninvestigation. In this paper, a generalized formula is found for the spectral\nweight function which incorporates both narrow and broad resonance cases.\nWithin L\\\"uscher's formalism, it is shown that the volume dependence of the\nspectral weight function exhibits a single-particle behavior for a extremely\nnarrow resonance and a two-particle behavior for a broad resonance. The\ncorresponding formulas for both $A^+_1$ and $T^-_1$ channels are derived. The\npotential application of these formulas in the extraction of resonance\nparameters are also discussed."
    },
    {
        "anchor": "New results from APE with non-perturbatively improved Wilson fermions: We present the results for light hadron spectrum, decay constants and the\nquark masses obtained with non-perturbatively improved Wilson fermions. We also\ngive our preliminary results for the heavy-light decay constants.",
        "positive": "Lattice computation of the electromagnetic contributions to kaon and\n  pion masses: We present a lattice calculation of the electromagnetic (EM) effects on the\nmasses of light pseudoscalar mesons. The simulations employ 2+1 dynamical\nflavors of asqtad QCD quarks, and quenched photons. Lattice spacings vary from\n$\\approx 0.12$ fm to $\\approx 0.045$ fm. We compute the quantity $\\epsilon$,\nwhich parameterizes the corrections to Dashen's theorem for the $K^+$-$K^0$ EM\nmass splitting, as well as $\\epsilon_{K^0}$, which parameterizes the EM\ncontribution to the mass of the $K^0$ itself. An extension of the\nnonperturbative EM renormalization scheme introduced by the BMW group is used\nin separating EM effects from isospin-violating quark mass effects. We correct\nfor leading finite-volume effects in our realization of lattice electrodynamics\nin chiral perturbation theory, and remaining finite-volume errors are\nrelatively small. While electroquenched effects are under control for\n$\\epsilon$, they are estimated only qualitatively for $\\epsilon_{K^0}$, and\nconstitute one of the largest sources of uncertainty for that quantity. We find\n$\\epsilon = 0.78(1)_{\\rm stat}({}^{+\\phantom{1}8}_{-11})_{\\rm syst}$ and\n$\\epsilon_{K^0}=0.035(3)_{\\rm stat}(20)_{\\rm syst}$. We then use these results\non 2+1+1 flavor pure QCD HISQ ensembles and find $m_u/m_d = 0.4529(48)_{\\rm\nstat}( {}_{-\\phantom{1}67}^{+150})_{\\rm syst}$."
    },
    {
        "anchor": "Meson spectra from overlap fermion on domain wall gauge configurations: We report meson spectra obtained by using valence overlap fermion propagators\ngenerated on a background of 2+1 flavor domain wall fermion gauge\nconfigurations on 16^3 X 32, 24^3 X 64 and 32^3 X 64 lattices. We use\nmany-to-all correlators with Z3 grid source and low eigenmode substitution\nwhich is efficient in reducing errors for the hadron correlators. The\npreliminary results on meson spectrum, a0 correlators, and charmonium hyperfine\nsplitting for three sea quark masses are reported here.",
        "positive": "Lattice calculation of the R-ratio smeared with Gaussian kernel: The ratio $R(E)$ of the cross-sections for $e^+e^-\\to$ hadrons and $e^+e^-\\to\n\\mu^+\\mu^-$ is a valuable energy-dependent probe of the hadronic sector of the\nStandard Model. Moreover, the experimental measurements of $R(E)$ are the\ninputs of the dispersive calculations of the leading hadronic vacuum\npolarization contribution to the muon $g-2$ and these are in significant\ntension with direct lattice calculations and with the muon $g-2$ experiment. In\nthis talk we discuss the results of our first-principles lattice study of\n$R(E)$. By using a recently proposed method for extracting smeared spectral\ndensities from Euclidean lattice correlators, we have calculated $R(E)$\nconvoluted with Gaussian kernels of different widths $\\sigma$ and central\nenergies up to $2.5$ GeV. Our theoretical results have been compared with the\nKNT19 [1] compilation of experimental results smeared with the same Gaussian\nkernels and a tension (about three standard deviations) has been observed for\n$\\sigma\\sim 600$ MeV and central energies around the $\\rho$-resonance peak."
    },
    {
        "anchor": "Ising description of the transition region in SU(3) gauge theory at\n  finite temperature: We attempt the numerical construction of an effective action in three\ndimensions for Ising spins which represent the Wilson lines in the\nfour-dimensional SU(3) gauge theory at finite temperature. For each\nconfiguration of the gauge theory, each spin is determined by averaging the\nWilson lines over a small neighborhood and then projecting the average to +/-1\naccording to whether the neighborhood is ordered or disordered. The effective\nIsing action, determined via the lattice Schwinger-Dyson equations, contains\neven (two-spin) and odd (one- and three-spin) terms with short range. We find\nthat the truncation to Ising degrees of freedom produces an effective action\nwhich is discontinuous across the gauge theory's phase transition. This\ndiscontinuity may disappear if the effective action is made more elaborate.",
        "positive": "Quark propagator at finite temperature and finite momentum in quenched\n  lattice QCD: We present an analysis of the quark spectral function above and below the\ncritical temperature for deconfinement performed at zero and non-zero momentum\nin quenched lattice QCD using clover improved Wilson fermions in Landau gauge.\nIt is found that the temporal quark correlation function in the deconfined\nphase near the critical temperature is well reproduced by a two-pole ansatz for\nthe spectral function. This indicates that excitation modes of the quark field\nhave small decay rates. The bare quark mass and momentum dependence of the\nspectral function is analyzed with this ansatz. In the chiral limit we find\nthat the quark spectral function has two collective modes corresponding to the\nnormal and plasmino excitations in the high temperature limit. Over a rather\nwide temperature range in the deconfined phase the pole mass of these modes at\nzero momentum, which corresponds to the thermal mass of the quark, is\napproximately proportional to temperature. With increasing bare quark masses\nthe plasmino mode gradually disappears and the spectral function is dominated\nby a single pole. We also discuss quasi-particle properties of heavy quarks in\nthe deconfined phase. In the confined phase, it is found that the pole ansatz\nfor the spectral function fails completely."
    },
    {
        "anchor": "Non-degenerate light quark masses from 2+1f lattice QCD+QED: We report on a calculation of the effects of isospin breaking in Lattice\nQCD+QED. This involves using Chiral Perturbation Theory with Electromagnetic\ncorrections to find the renormalized, non-degenerate, light quark masses. The\ncalculations are carried out on QCD ensembles generated by the RBC and UKQCD\ncollaborations using Domain Wall Fermions and the Iwasaki and Iwasaki+DSDR\nGauge Actions with unitary pion masses down to 170 MeV. Non-compact QED is\ntreated in the quenched approximation. The simulations use a $32^3$ lattice\nsize with $a^{-1}=2.28(3)$ GeV (Iwasaki) and 1.37(1) (Iwasaki+DSDR). This\nbuilds on previous work from the RBC/UKQCD collaboration with lattice spacing\n$a^{-1}=1.78(4)$ GeV.",
        "positive": "Non-perturbative renormalization of three-quark operators: High luminosity accelerators have greatly increased the interest in\nsemi-exclusive and exclusive reactions involving nucleons. The relevant\ntheoretical information is contained in the nucleon wavefunction and can be\nparametrized by moments of the nucleon distribution amplitudes, which in turn\nare linked to matrix elements of local three-quark operators. These can be\ncalculated from first principles in lattice QCD. Defining an RI-MOM\nrenormalization scheme, we renormalize three-quark operators corresponding to\nlow moments non-perturbatively and take special care of the operator mixing.\nAfter performing a scheme matching and a conversion of the renormalization\nscale we quote our final results in the MSbar scheme at mu=2 GeV."
    },
    {
        "anchor": "Chiral fermions in two dimensions?: Quenched studies of a global U(1) symmetric Wilson-Yukawa model in two\ndimensions show no evidence of a charged fermion in the vortex phase at strong\nWilson-Yukawa coupling while there is strong indication of a massive neutral\nfermion. However, with the U(1)$_L$ gauge field turned on, we use dimensional\narguments to suggest that the neutral fermion appears to couple chirally to a\nmassive vector boson state.",
        "positive": "Exploring the Phase Diagram with Taylor Series: Epic Voyage or Just\n  Another Bad Trip: It has been suggested in the literature that it may be possible to locate the\nQCD critical end point using the Taylor series of thermodynamic variables about\nthe $\\mu=0$ axis. Since the phase transition at the critical end point is\nbelieved to be in the 3D Ising universality class, it would seem natural to\ntest this method with the Ising Model, for which the answer is already known.\nThe finding is that it is in fact possible to pinpoint the location of the\nIsing critical point using Taylor coefficients."
    },
    {
        "anchor": "Looking for $U(1)_A$ Restoration in Hot QCD with Domain Wall Fermions: The effects of the axial anomaly are suppressed at high temperatures due to\nscreening effects in the quark-gluon plasma. If the suppression is nearly\ncomplete close to the chiral transition temperature, this can have consequences\nfor the nature of the phase transition. The use of a chiral action such as\nDomain Wall Fermions allows us to gain a deeper insight into the issue. Our\nlattice sizes were $16^3\\times 8\\times L_s$, with $L_s=32$ or 48, and our pion\nmass was approximately 200 MeV. We found that $U(1)_A$ stayed broken above the\nchiral transition. However the breaking was found to be due to topologically\nnontrivial configurations which raises the question as to whether it persists\nin the thermodynamic limit. We also present results for the eigenvalue density\nof the Dirac operator. It is seen that although the density decreases\ndramatically across the chiral transition temperature, $U(1)_A$ still remains\nbroken at our current volume and quark mass due to the presence of zero modes.",
        "positive": "The sign problem across the QCD phase transition: The average phase factor of the QCD fermion determinant signals the strength\nof the QCD sign problem. We compute the average phase factor as a function of\ntemperature and baryon chemical potential using a two-flavor NJL model. This\nallows us to study the strength of the sign problem at and above the chiral\ntransition. It is discussed how the $U_A(1)$ anomaly affects the sign problem.\nFinally, we study the interplay between the sign problem and the endpoint of\nthe chiral transition."
    },
    {
        "anchor": "Exploring interpolating momentum schemes: We compute the renormalisation factors of the quark mass and wave function\nusing IMOM (Interpolating MOMenta) schemes. The framework is the\nRome-Southampton non-renormalisation method, but the momentum transfer in the\nquark bilinears is not restricted to zero or to the symmetric point. We study\nthe scale dependence, infrared contamination and lattice artefacts for\ndifferent values of this momentum transfer and for two different kinds of\nprojectors. For the numerical simulations, we use data generated by the\nRBC-UKQCD collaborations, with $N_f = 2+1$ flavours of Domain-Wall fermions,\nand inverse lattice spacing of $1.79 $ and $2.38$ GeV.",
        "positive": "The Phase Diagram of Compact QED Coupled to a Four-Fermi Interaction: Compact lattice Quantum Electrodynamics (QED) with four species of fermions\nis simulated with massless quarks by using the $\\chi$QED scheme of adding a\nfour-fermi interaction to the action. Simulations directly in the chiral limit\nof massless quarks are done with high statistics on $8^4$, and $16^4$ lattices,\nand the phase diagram, parameterized by the gauge and the four-fermi couplings,\nis mapped out. The line of monopole condensation transitions is separate from\nthe line of chiral symmetry restoration. The simulation results indicate that\nthe monopole condensation transition is first order while the chiral transition\nis second order. The challenges in determining the Universality class of the\nchiral transition are discussed. If the scaling region for the chiral\ntransition is sufficiently wide, the $16^4$ simulations predict critical\nindices far from mean field values. We discuss a speculative scenario in which\nanti-screening provided by double-helix strands of monopole and anti-monopole\nloops are the agent that balances the screening of fermion anti-fermion pairs\nto produce an ultra-violet fixed point in the electric coupling."
    },
    {
        "anchor": "Constraining $1+\\mathcal{J}\\to 2$ coupled-channel amplitudes in\n  finite-volume: Whether one is interested in accessing the excited spectrum of hadrons or\ntesting the standard model of particle physics, electroweak transition\nprocesses involving multi-hadron channels in the final state play an important\nrole in a variety of experiments. Presently the primary theoretical tool with\nwhich one can study such reactions is lattice QCD, which is defined in a finite\nspacetime volume. In this work, we investigate the feasibility of implementing\nexisting finite-volume formalism in realistic lattice QCD calculation of\nreactions in which a stable hadron can transition to one of several two-hadron\nchannels under the action of an external current. We provide a conceptual\ndescription of the coupled-channel transition formalism, a practical roadmap\nfor carrying out a calculation, and an illustration of the approach using\nsynthetic data for two non-trivial resonant toy models. The results provide a\nproof-of-principle that such reactions can indeed be constrained using\nmodern-day lattice QCD calculations, motivating explicit computation in the\nnear future.",
        "positive": "Non-perturbative quark mass renormalization in two-flavor QCD: The running of renormalized quark masses is computed in lattice QCD with two\nflavors of massless O(a) improved Wilson quarks. The regularization and flavor\nindependent factor that relates running quark masses to the renormalization\ngroup invariant ones is evaluated in the Schroedinger Functional scheme. Using\nexisting data for the scale r_0 and the pseudoscalar meson masses, we define a\nreference quark mass in QCD with two degenerate quark flavors. We then compute\nthe renormalization group invariant reference quark mass at three different\nlattice spacings. Our estimate for the continuum value is converted to the\nstrange quark mass with the help of chiral perturbation theory."
    },
    {
        "anchor": "Color superconductivity in ultra-dense quark matter: At ultra-high density, matter is expected to form a degenerate Fermi gas of\nquarks in which there is a condensate of Cooper pairs of quarks near the Fermi\nsurface. This phenomenon is called color superconductivity. In these\nproceedings I review the underlying physics of color superconductivity and our\ncurrent understanding of the possible phases of real-world quark matter. Then I\nconsider how lattice gauge theorists would proceed to investigate the phase\nstructure of dense quark matter if it were possible to perform the path\nintegral numerically, i.e. if the sign problem had been solved.",
        "positive": "Improved determination of hadron matrix elements using the variational\n  method: The extraction of hadron form factors in lattice QCD using the standard two-\nand three-point correlator functions has its limitations. One of the most\ncommonly studied sources of systematic error is excited state contamination,\nwhich occurs when correlators are contaminated with results from higher energy\nexcitations. We apply the variational method to calculate the axial vector\ncurrent gA and compare the results to the more commonly used summation and\ntwo-exponential fit methods. The results demonstrate that the variational\napproach offers a more efficient and robust method for the determination of\nnucleon matrix elements."
    },
    {
        "anchor": "Lattice QCD at non-vanishing density: phase diagram, equation of state: We propose a method to study lattice QCD at non-vanishing temperature (T) and\nchemical potential (\\mu). We use n_f=2+1 dynamical staggered quarks with\nsemi-realistic masses on L_t=4 lattices. The critical endpoint (E) of QCD on\nthe Re(\\mu)-T plane is located. We calculate the pressure (p), the energy\ndensity (\\epsilon) and the baryon density (n_B) of QCD at non-vanishing T and\n\\mu.",
        "positive": "Chiral Yukawa models in the planar limit: We consider the most general renormalizable chiral Yukawa model with\n$SU(3)_{\\rm color}$ replaced by $SU(N_c)$, $SU(2)_{\\rm L}$ replaced by $SU(N_w\n)$ and $U(1)_{Y}$ replaced by $U(1)^{N_w -1}$ in the limit $N_c\n\\rightarrow\\infty$, $N_w \\rightarrow\\infty$ with the ratio\n$\\rho=\\sqrt{{N_w}\\over{N_c}} \\ne 0,\\infty$ held fixed. Since for $N_w \\ge 3$\nonly one renormalizable Yukawa coupling per family exists and there is no\nmixing between families the limit is appropriate for the description of the\neffects of a heavy top quark when all the other fermions are taken to be\nmassless. A rough estimate of the triviality bound on the Yukawa coupling is\nequivalent to $m_t \\le 1~TeV$."
    },
    {
        "anchor": "Hadron-hadron total cross sections and soft high-energy scattering on\n  the lattice: The nonperturbative approach to soft high-energy hadron-hadron scattering,\nbased on the analytic continuation of Euclidean Wilson-loop correlation\nfunctions, makes possible the investigation of the problem of the asymptotic\nenergy dependence of hadron-hadron total cross sections by means of lattice\ncalculations. In this contribution we compare the lattice numerical results to\nanalytic results obtained with various nonperturbative techniques. We also\ndiscuss the possibility to obtain indications of the rise of hadron-hadron\ntotal cross sections with energy directly from the lattice data.",
        "positive": "The chiral limit of non-compact QED(3): Non-compact QED(3) with four-component fermion flavor content larger than or\nequal to two is studied numerically near the chiral limit to understand its\nchiral symmetry breaking features. We monitor discretization and finite size\neffects on the chiral condensate by simulating the model at different values of\nthe gauge coupling on lattices ranging in size from 10^3 to 50^3. Our upper\nbound for the dimensionless condensate beta^2<psibarpsi> in the N_f=2 case is\n5x10^{-5}."
    },
    {
        "anchor": "A New Approach to the Problem of Dynamical Quarks in Numerical\n  Simulations of Lattice QCD: Lattice QCD with an even number of degenerate quark flavours is shown to be a\nlimit of a local bosonic field theory. The action of the bosonic theory is real\nand bounded from below so that standard simulation algorithms can be expected\nto apply. The feasibility of such calculations is discussed, but no practical\ntests have yet been made.",
        "positive": "The monopole mass in the random percolation gauge theory: We study the behaviour of the monopole at finite temperature in the\n(2+1)-dimensional lattice gauge theory dual to the percolation model; by\nexploiting the correspondences to statistical systems, we possess powerful\ntools to evaluate the monopole mass both above and below the critical\ntemperature with high-precision Monte Carlo simulations."
    },
    {
        "anchor": "Quantum fluctuations of k-strings: A case study: K strings in Yang-Mills theory can be considered as bound states of k\nelementary confining strings carrying one unit of colour flux. Current\nestimates of k-string tension sigma_k are very sensitive to the leading\ncorrections due to quantum fluctuations of the string. In this study we address\nthis problem by comparing Polyakov-Polyakov correlators in the fundamental\nrepresentation (k=1) with the corresponding ones with k=2 in the confining\nphase of a Z_4 gauge theory in three dimensions. Highly efficient simulation\ntechniques are available in this case. Although the k=1 Polyakov-Polyakov\ncorrelator matches nicely with the expected bosonic string effects up to the\nNext-to-Leading-Order, the k=2 Polyakov-Polyakov correlators show large\ndeviations. This is an important source of potential systematic errors in the\ncurrent estimates of sigma_k.",
        "positive": "Study of the Higgs-Yukawa theory in the strong-Yukawa coupling regime: In this article, we present an ongoing lattice study of the Higgs-Yukawa\nmodel, in the regime of strong-Yukawa coupling, using overlap fermions. We\ninvestigated the phase structure in this regime by computing the Higgs vacuum\nexpectation value, and by exploring the finite-size scaling behaviour of the\nsusceptibility corresponding to the magnetisation. Our preliminary results\nindicate the existence of a second-order phase transition when the Yukawa\ncoupling becomes large enough, at which the Higgs vacuum expectation value\nvanishes and the susceptibility diverges."
    },
    {
        "anchor": "Dynamical suppression of large instantons: We investigate the distribution of instanton sizes in the framework of a\nsimplified model for ensembles of instantons. This model takes into account the\nnon-diluteness of instantons. The infrared problem for the integration over\ninstanton sizes is dealt with in a self-consistent manner by approximating\ninstanton interactions by a repulsive hard core potential. This leads to a\ndynamical suppression of large instantons. The characteristic features of the\ninstanton size distribution are studied by means of analytic and Monte Carlo\nmethods. We find a power law behaviour for small sizes, consistent with the\nsemi-classical results. At large instanton sizes the distribution decays\nexponentially. The results are compared with those from lattice simulations.",
        "positive": "Aspects of Confinement in Coulomb Gauge: I present some new results regarding confinement as it appears in Coulomb\ngauge. It is found that: i) a recently proposed Yang-Mills vacuum\nwavefunctional in temporal gauge and 2+1 dimensions yields a Coulomb-gauge\nghost propagator and linear Coulomb potential in good agreement with lattice\nMonte Carlo results; ii) adding a few constituent gluons to heavy\nquark-antiquark states brings the interaction energy much closer to that of the\nstatic quark potential, and suggests the beginnings of gluon-chain formation at\nroughly one fermi; iii) a perturbative approach to Faddeev-Popov eigenvalues\nindicates that the zero eigenvalue at the Gribov horizon may occur either at,\nor away from, p=0, depending on the gauge choice and spacetime dimension. This\nlast result may be relevant to the qualitatively different infrared behavior of\nthe ghost propagator in Coulomb and Landau gauges."
    },
    {
        "anchor": "NRQCD based S- and P-wave bottomonium spectra at finite temperature from\n  $48^3 \\times 12$ lattices with $N_f=2+1$ light HISQ flavors: We study S-wave and P-wave bottomonium spectral functions at non-zero\ntemperature in 2+1 flavor QCD using the NRQCD formulation for bottom quarks. We\nuse a novel Bayesian approach to reconstruct the spectral functions and find\nthat $\\chi_{b1}$ survives up to $T=249 {\\rm MeV}$. We also study the effect of\ndifferent temporal discretizations of the NRQCD formalism on the bottomonium\ncorrelation functions",
        "positive": "A scalable PC-based parallel computer for lattice QCD: A PC-based parallel computer for medium/large scale lattice QCD simulations\nis suggested. The Eotvos Univ., Inst. Theor. Phys. cluster consists of 137\nIntel P4-1.7GHz nodes. Gigabit Ethernet cards are used for nearest neighbor\ncommunication in a two-dimensional mesh. The sustained performance for\ndynamical staggered(wilson) quarks on large lattices is around 70(110) GFlops.\nThe exceptional price/performance ratio is below $1/Mflop."
    },
    {
        "anchor": "Heavy quark momentum diffusion from the lattice using gradient flow: We apply the gradient flow on a color-electric two-point function that\nencodes the heavy quark momentum diffusion coefficient. The simulations are\ndone on fine isotropic lattices in the quenched approximation at $1.5\\,T_c$.\nThe continuum extrapolation is performed at fixed flow time followed by a\nsecond extrapolation to zero flow time. Perturbative calculations of this\ncorrelation function under Wilson flow are used to enhance the extrapolations\nof the non-perturbative lattice correlator. The final estimate for the\ncontinuum correlator at zero flow time largely agrees with one obtained from a\nprevious study using the multi-level algorithm. We perform a spectral\nreconstruction based on perturbative model fits to estimate the heavy quark\nmomentum diffusion coefficient. The approach we present here yields\nhigh-precision data for the correlator and is also applicable for actions with\ndynamical fermions.",
        "positive": "Algorithms for Dynamical Fermions: This is the write-up of three lectures on algorithms for dynamical fermions\nthat were given at the ILFTN workshop 'Perspectives in Lattice QCD' in Nara\nduring November 2005. The first lecture is on the fundamentals of Markov Chain\nMonte Carlo methods and introduces the Hybrid Monte Carlo (HMC) algorithm and\nsymplectic integrators; the second lecture covers topics in approximation\ntheory and thereby introduces the Rational Hybrid Monte Carlo (RHMC) algorithm\nand ways of evading integrator instabilities by means of multiple pseudofermion\nfields; the third lecture introduces on-shell chiral (Ginsparg-Wilson) lattice\nfermions and discusses five-dimensional formulations for computing fermion\npropagators for such fermions."
    },
    {
        "anchor": "Grand-Canonical simulation of 4D simplicial quantum gravity: A thorough numerical examination for the field theory of 4D quantum gravity\n(QG) with a special emphasis on the conformal mode dependence has been studied.\nMore clearly than before, we obtain the string susceptibility exponent of the\npartition function by using the Grand-Canonical Monte-Carlo method. Taking\nthorough care of the update method, the simulation is made for 4D Euclidean\nsimplicial manifold coupled to $N_X$ scalar fields and $N_A$ U(1) gauge fields.\nThe numerical results suggest that 4D simplicial quantum gravity (SQG) can be\nreached to the continuum theory of 4D QG. We discuss the significant property\nof 4D SQG.",
        "positive": "Quasi particles in hot QCD: We show at very high temperature how the behaviour of the spatial 't Hooft\nloop in the QCD plasma is simply related to the chromo electric flux of the\ngluons. This simple picture is vindicated by a systematic quasi classical\napproach. The spatial Wilson loop 's behaviour is computed by a similar nearly\nfree plasma of magnetic quasiparticles. This model predicts unambiguously\nratios of multiply charged Wilson loops. Recent simulations confirm these\npredictions accurately."
    },
    {
        "anchor": "QED self energies from lattice QCD without power-law finite-volume\n  errors: Using the infinite-volume photon propagator, we developed a method which\nallows us to calculate electromagnetic corrections to stable hadron masses with\nonly exponentially suppressed finite-volume effects. The key idea is that the\ninfinite volume hadronic current-current correlation function with large time\nseparation between the two currents can be reconstructed by its value at modest\ntime separation, which can be evaluated in finite volume with only\nexponentially suppressed errors. This approach can be extended to other\npossible applications such as QED corrections to (semi-)leptonic decays and\nsome rare decays.",
        "positive": "Thermalization of Yang-Mills theory in a $(3+1)$ dimensional small\n  lattice system: We study the real-time evolution of SU($2$) Yang-Mills theory in a $(3+1)$\ndimensional small lattice system after interaction quench. We numerically solve\nthe Schr{\\\"o}dinger equation with the Kogut-Susskind Hamiltonian in the\nphysical Hilbert space obtained by solving Gauss law constraints. We observe\nthe thermalization of a Wilson loop to the canonical state; the relaxation time\nis insensitive to the coupling strength, and estimated as $\\tau_{\\rm eq}\\sim\n2\\pi/T$ with temperatures $T$ at steady states. We also compute the vacuum\npersistence probability (the Loschmidt echo) to understand the relaxation from\nthe dynamics of the wave function."
    },
    {
        "anchor": "Shifted unitary orthogonal methods for the overlap inversion: In this work we compare the convergence of the shifted unitary orthogonal\nmethod (SUOM) and different Krylov subspace solvers for propagator computations\nwith overlap fermions. We show that the SUOM algorithm performs similarly to\nthe shifted unitary minimal residual method (SUMR) with the latter converging\nslightly faster. When the geometric optimality is applied to SUOM we get e new\nalgorithm which is faster than SUMR.",
        "positive": "Faster Fermions in the Tempered Hybrid Monte Carlo Algorithm: Tempering is used to change the quark mass while remaining in equilibrium\nbetween the trajectories of a standard hybrid Monte Carlo simulation of four\nflavours of staggered fermions. The algorithm is faster for small enough quark\nmasses, and particularly so when more than one mass is required."
    },
    {
        "anchor": "Progress in generating gauge ensembles with Stabilized Wilson Fermions: The continued generation of $N_f=2+1$ quark flavor gauge configurations using\nstabilized Wilson fermions by the open lattice initiative (OpenLat) is\nreported. We present the status of our ongoing production and show updates on\nincreasing statistics at the four lattice spacings $a=0.12, 0.094, 0.077$ and\n$0.064$ fm. Aside from the $SU(3)$ flavor symmetric point we discuss\nadvancements in going towards physical pion masses. We show preliminary results\nof the pion decay constants, extending previous results, and discuss further\nvalidation observables on the available ensembles.",
        "positive": "Precise determination of the lattice spacing in full lattice QCD: We compare three different methods to determine the lattice spacing in\nlattice QCD and give results from calculations on the MILC ensembles of\nconfigurations that include the effect of $u$, $d$ and $s$ sea quarks. It is\nuseful, for ensemble to ensemble comparison, to express the results as giving a\nphysical value for $r_1$, a parameter from the heavy quark potential. Combining\nthe three methods gives a value for $r_1$ in the continuum limit of\n0.3133(23)(3) fm. Using the MILC values for $r_0/r_1$, this corresponds to a\nvalue for the $r_0$ parameter of 0.4661(38) fm. We also discuss how to use the\n$\\eta_s$ for determining the lattice spacing and tuning the $s$-quark mass\naccurately, by giving values for $m_{\\eta_s}$ (0.6858(40) GeV) and $f_{\\eta_s}$\n(0.1815(10) GeV)."
    },
    {
        "anchor": "A note on improved stochastic trace estimation for fermionic string\n  fluctuations: We report on the use of a stochastic trace estimator algorithm, based on\nmutually unbiased bases, for evaluating the trace of a matrix differential\noperator appearing in the context of lattice simulations for the discretized\nsuperstring worldsheet. A study of the variance, in a setup which is slightly\nmodified with respect to the original one, confirms advantages with respect to\nmore traditional methods like the Gaussian estimator.",
        "positive": "Lattice Calculation of the $K_L$-$K_S$ mass difference: We report progress on calculating the $K_L$-$K_S$ mass difference in lattice\nQCD. T he calculation is performed on a 2+1 flavor, domain wall fermion,\n$16^3\\times 32$ en semble with a 421 MeV pion mass. We include only\ncurrent-current operators and drop all disconnected and double penguin diagrams\nin the calculation. The calculation is made finite through the GIM mechanism by\nintroducing a valence charm quark. The long distance effects are discussed\nseparately for each of the two parity channels. Whil e we find a clear long\ndistance contribution from the parity odd channel, the signal to noise ratio in\nthe parity even channel is exponentially decreasing and the two-p ion state can\nbe seen in only a subclass of amplitudes. We obtain the mass differenc e\n$\\Delta M_K$ in a range from $5.12(24)\\times 10^{-12}$ to $9.31(66) \\times\n10^{-12}$ MeV for kaon masses between 563 and 839 MeV."
    },
    {
        "anchor": "Light hadron masses with an $O(a^2)$ improved NNN action: Meson and baryon masses in the light (u,d and s) sector are calculated using\ntadpole-improved gauge field and fermion actions. These are corrected to order\n$O(a^2)$ on the classical level using next-nearest-neighbour terms. The\nresults, obtained at lattice spacings of 0.4 and 0.27fm, are compared to Wilson\naction calculations.",
        "positive": "Infrared fixed point in the massless twelve-flavor SU(3) gauge-fermion\n  system: We present strong numerical evidence for the existence of an infrared fixed\npoint in the renormalization group flow of the SU(3) gauge-fermion system with\ntwelve massless fermions in the fundamental representation. Our numerical\nsimulations using nHYP-smeared staggered fermions with Pauli-Villars\nimprovement do not exhibit any first-order bulk phase transition in the\ninvestigated parameter region. We utilize an infinite volume renormalization\nscheme based on the gradient flow transformation to determine the\nrenormalization group $\\beta$ function. We identify an infrared fixed point at\n$g^2_{\\mathrm{GF}\\star}=6.60(62)$ in the GF scheme and calculate the leading\nirrelevant critical exponent $\\gamma_{g}^{\\star}=0.199(32)$. Our prediction for\n$\\gamma_{g}^{\\star}$ is consistent with available literature at the\n$1\\mbox{-}2\\sigma$ level."
    },
    {
        "anchor": "Schr\u00f6dinger functional boundary conditions and improvement of the\n  SU($N$) pure gauge action for $N>3$: The leading method to study the running coupling constant of non-abelian\ngauge theories is based on the Schr\\\"odinger functional scheme. However, the\nboundary conditions and $\\mathcal{O}(a)$ improvement have not been\nsystematically generalized for theories with more than three colors. These\ntheories have applications in BSM model building as well as in the large $N$\nlimit. We have studied the boundary conditions and improvement for the pure\nYang-Mills theory within the Schr\\\"odinger functional scheme. We have\ndetermined for all values of $N$ the boundary fields which provide high\nsignal/noise ratio. Additionally, we have calculated the improvement\ncoefficient $c_t$ for the pure gauge to one loop order for SU($N$) gauge\ntheories with $N=2,\\ldots,8$ from which $N\\geq 4$ are previously unknown.",
        "positive": "Cooling in QCD Spectroscopy: We test the cooling algorithm with gluonic and staggered hadronic\nspectroscopy on $SU(3)$ gauge field configurations generated with two flavors\nof staggered dynamical fermions. We find cooling is not reliable as the basis\nfor improved hadronic operators. We also find that performing cooling sweeps to\nreveal more clearly the topological properties of the gauge fields eliminates\nthe spin structure of the hadron spectrum."
    },
    {
        "anchor": "Towards the Application of Skewed Detailed Balance in Lattice Gauge\n  Theories: State-of-the-art algorithms in lattice gauge theory typically rely heavily on\ndetailed balance, which is an instrumental tool to prove the correct\nconvergence of the Markov Chain Monte Carlo Algorithm. In this work, we\ninvestigate an alternative to detailed balance, skewed detailed balance, and\nthe prospects of alleviating the topological freezing problem by studying the\none-dimensional $O\\left(2\\right)$ model.",
        "positive": "The Polyakov loop models in the large N limit: Phase diagram at finite\n  density: The 't Hooft-Veneziano limit of various U(N) and SU(N) Polyakov loop models\nis constructed at finite temperature and non-zero baryon chemical potential. In\nthis paper we calculate the free energy, its derivatives, the Polyakov loop\nexpectation values and the baryon density. The phase diagram is described in\ndetails."
    },
    {
        "anchor": "No confinement without Coulomb confinement: We compare the physical potential $V_D(R)$ of an external quark-antiquark\npair in the representation $D$ of SU(N), to the color-Coulomb potential $V_{\\rm\ncoul}(R)$ which is the instantaneous part of the 44-component of the gluon\npropagator in Coulomb gauge, $D_{44}(\\vx,t) = V_{\\rm coul}(|\\vx|) \\delta(t)$ +\n(non-instantaneous). We show that if $V_D(R)$ is confining, $\\lim_{R \\to\n\\infty}V_D(R) = + \\infty$, then the inequality $V_D(R) \\leq - C_D V_{\\rm\ncoul}(R)$ holds asymptotically at large $R$, where $C_D > 0$ is the Casimir in\nthe representation $D$. This implies that $ - V_{\\rm coul}(R)$ is also\nconfining.",
        "positive": "Inclusive semileptonic $B$-decays from lattice QCD: We present the lattice QCD calculation of inclusive semileptonic $B_s$-meson\ndecays. We follow a recently proposed method, which is based on the extraction\nof smeared spectral densities from Euclidean correlation functions and on the\nnumerical reconstruction of the integration kernel relevant for the inclusive\ndecay rate calculation. We compute four-point Euclidean correlation functions\nusing JLQCD and ETM gauge ensembles with unphysically light $b$-quark masses,\nand apply two different methods for the integration kernel reconstruction.\nFinally, we show that the lattice results obtained in this work are in good\nagreement with the analytic predictions of the operator-product-expansion. This\nopens the path for a future full lattice QCD calculation to be used as\ntheoretical input for the determination of the magnitude of the CKM element\n$V_{cb}$."
    },
    {
        "anchor": "Confinement, the Abelian Decomposition, and the Contribution of Topology\n  to the Static Quark Potential: In the past few years, we have presented a new way of considering quark\nconfinement. Through a careful choice of a Cho-Duan-Ge Abelian Decomposition,\nwe can construct the QCD Wilson Loop in terms of an Abelian restricted field.\nThe relationship between the QCD and restricted string tensions is exact; and\nwe do not need to gauge fix, apply any path ordering of gauge links, or\nadditional path integrals. This hints at why mesons are colour neutral.\n  Furthermore, the Abelian restricted field contains two parts: a Maxwell term,\nand a topological term. The topological term can describe magnetic monopoles\nand other topological objects, which can be studied both numerically and\ntheoretically. By examining the topological part of the restricted field\nstrength we have found evidence suggesting that these objects, which will\ncontribute to confinement if present, are indeed there.\n  Previous studies have used simplifications, breaking the exact relationship\nbetween the restricted and QCD string tensions, but it was found that the\ntopological term dominated the restricted string tension. Here we remove those\nsimplifications, and show that the Abelian restricted field does indeed fully\nexplain confinement. However, our results for how much of the restricted string\ntension arises from the topological objects show strong dependence on the\nlattice spacing and level of smearing, so we are not yet able to draw a\ndefinitive conclusion.",
        "positive": "Targeting the Conformal Window: Scalars on the Lattice: The light Higgs boson of the Standard Model could arise as the consequence of\nthe weakly broken conformal symmetry in a strongly interacting gauge theory.\nHere we present a novel idea to study the transition from conformal to\nconfining behavior using an SU(3) gauge theory with four light and eight heavy\nflavors. This system interpolates between the 12-flavor conformal and the 4\nflavor chirally broken theory as the mass of the heavy flavors are varied. We\nshow first results on our determination of the iso-singlet 0++ state."
    },
    {
        "anchor": "D-Dbar Mixing in the Standard Model and Beyond from Nf=2 Twisted Mass\n  QCD: We present the first unquenched lattice QCD results for the bag parameters\ncontrolling the short distance contribution to D meson oscillations in the\nStandard Model and beyond. We have used the gauge configurations produced by\nthe European Twisted Mass Collaboration with Nf = 2 dynamical quarks, at four\nlattice spacings and light meson masses in the range 280-500 MeV.\nRenormalization is carried out non-perturbatively with the RI-MOM method. The\nbag-parameter results have been used to constrain New Physics effects in D-Dbar\nmixing, to put a lower bound to the generic New Physics scale and to constrain\noff-diagonal squark mass terms for TeV-scale Supersymmetry.",
        "positive": "Tensor-network study of the 3d $O(2)$ model at non-zero chemical\n  potential and temperature: We present results of tensor-network simulations of the three-dimensional\n$O(2)$ model at non-zero chemical potential and temperature, which were\ncomputed using the higher-order tensor-renormalization-group method (HOTRG).\nThis necessitated enhancements to the HOTRG blocking procedure to reduce the\ntruncation error in the case of anisotropic tensors. Moreover, the construction\nof the truncated vector spaces was adapted to strongly reduce the effect of\nsystematic errors in the computation of observables using the finite-difference\nmethod. Our (improved) HOTRG results for the evolution of the number density\nwith the chemical potential are in agreement with results obtained with the\nworm algorithm, and both the Silver Blaze phenomenon at zero temperature and\nthe temperature dependence of the number density can be adequately reproduced."
    },
    {
        "anchor": "The QCD equation of state and transition at finite temperature: We present the latest results for the equation of state and the crossover\ntransition in 2+1 flavor QCD from the HotQCD Collaboration. Bulk thermodynamic\nquantities - energy density, pressure, entropy density, and the speed of sound\n- are calculated on lattices with temporal extent $N_t = 8$ in the temperature\nrange 140 < T < 540 MeV. We utilize two improved staggered fermion actions,\nasqtad and p4, with the mass for the two degenerate light quarks chosen to be\n$m_{ud} = 0.1 m_s$, corresponding to $m_\\pi \\approx 220$ MeV for the lightest\npion. We also calculate observables that are sensitive to the chiral and\ndeconfing transitions - the light and strange quark number susceptibilities,\nthe chiral condensate, and the renormalized Polyakov loop - finding that\ndeconfinement and chiral symmetry restoration occur in the same narrow\ntemperature interval.",
        "positive": "Lattice computation of $B \\to D^*,\\;D^{**}\\ell \u03bd$ form factors at\n  finite heavy masses: We propose a strategy to compute form factors entering the semileptonic decay\nchannel of $B$ mesons into orbitally excited (P wave) $D^{**}$ charmed mesons\non the lattice using, for the first time, realistic charm quarks having a\nfinite mass. We present preliminary results about the extracted transition\namplitudes and form factors at different recoils and at three different $b$\nquark masses."
    },
    {
        "anchor": "Effects of Quenching and Partial Quenching on Penguin Matrix Elements: In the calculation of non-leptonic weak decay rates, a \"mismatch\" arises when\nthe QCD evolution of the relevant weak hamiltonian down to hadronic scales is\nperformed in unquenched QCD, but the hadronic matrix elements are then computed\nin (partially) quenched lattice QCD. This mismatch arises because the\ntransformation properties of penguin operators under chiral symmetry change in\nthe transition from unquenched to (partially) quenched QCD. Here we discuss\nQCD-penguin contributions to $\\Delta S=1$ matrix elements, and show that new\nlow-energy constants contribute at leading order in chiral perturbation theory\nin this case. In the partially quenched case (in which sea quarks are present),\nthese low-energy constants are related to electro-magnetic penguins, while in\nthe quenched case (with no sea quarks) no such relation exists. As a simple\nexample, we give explicit results for $K^+\\to\\pi^+$ and $K^0\\to vacuum$ matrix\nelements, and discuss the implications for lattice determinations of\n$K\\to\\pi\\pi$ amplitudes from these matrix elements.",
        "positive": "Absence of Parity-Flavor Breaking Phase in QCD with two Flavors of\n  Wilson fermions for beta greater than or equal to 5.0: We present data testing the existence of a parity-flavor breaking phase in\nsimulations of QCD with two flavors of light Wilson fermions. This is done by\nexplicit simulations on lattice sizes of $6^4$, $8^4$ and $10^4$ for a variety\nof values of $\\beta$ and $\\kappa$ as well as the coefficient, $h$, of an\nexplicit breaking term included in the action. We find that at $\\beta=6/g^2 $\nequal to or greater than 5.0 extrapolation in the parameter $h$ as well as in\nthe lattice volume show no indication of a phase where parity and flavor are\nspontaneously broken in the limit of zero $h$."
    },
    {
        "anchor": "Separating perturbative and non-perturbative contributions to the\n  plaquette: We try to separate the perturbative and non-perturbative contributions to the\nplaquette of pure SU(3) gauge theory. To do this we look at the large-n\nasymptotic behaviour of the perturbation series in order to estimate the\ncontribution of the as-yet uncalculated terms in the series. We find no\nevidence for the previously reported Lambda^2 contribution to the gluon\ncondensate. Attempting to determine the conventional Lambda^4 condensate gives\na value of approximately 0.03(2) GeV^4, in reasonable agreement with sum rule\nestimates, though with very large uncertainties.",
        "positive": "Perturbative two- and three-loop coefficients from large beta Monte\n  Carlo: Perturbative coefficients for Wilson loops and the static quark self-energy\nare extracted from Monte Carlo simulations at large beta on finite volumes,\nwhere all the lattice momenta are large. The Monte Carlo results are in\nexcellent agreement with perturbation theory through second order. New results\nfor third order coefficients are reported. Twisted boundary conditions are used\nto eliminate zero modes and to suppress Z_3 tunneling."
    },
    {
        "anchor": "G parity boundary conditions and Delta I = 1/2, K to pi pi decays: The use of G-parity boundary conditions to compute Delta I = 1/2, K to pi pi\ndecays is reviewed and a method to consistently treat both the pions and kaon\nin full QCD proposed. This approach creates a physical, final-state, pion\nmomentum using a 3 fm box and avoids statistical noise coming from pions with\nsmaller momentum.",
        "positive": "Fractional electric charge and quark confinement: Owing to their fractional electric charges, quarks are blind to\ntransformations that combine a color center phase with an appropriate\nelectromagnetic one. Such transformations are part of a global $Z_6$-like\ncenter symmetry of the Standard Model that is lost when quantum chromodynamics\n(QCD) is treated as an isolated theory. This symmetry and the corresponding\ntopological defects may be relevant to non-perturbative phenomena such as quark\nconfinement, much like center symmetry and ordinary center vortices are in pure\nSU($N$) gauge theories. Here we report on our investigations of an analogous\nsymmetry in a 2-color model with dynamical Wilson quarks carrying half-integer\nelectric charge."
    },
    {
        "anchor": "Applications of Chiral Perturbation theory to lattice QCD: These lectures describe the use of effective field theories to extrapolate\nresults from the parameter region where numerical simulations of lattice QCD\nare possible to the physical parameters (physical quark masses, infinite\nvolume, vanishing lattice spacing, etc.). After a brief introduction and\noverview, I discuss three topics: 1) Chiral perturbation theory in the\ncontinuum; 2) The inclusion of discretization effects into chiral perturbation\ntheory, focusing on the application to Wilson and twisted-mass lattice\nfermions; 3) Extending chiral perturbation theory to describe partially\nquenched QCD.",
        "positive": "Controlling One-Dimensional Langevin Dynamics on the Lattice: Stochastic evolutions of classical field theories have recently become\npopular in the study of problems such as determination of the rates of\ntopological transitions and the statistical mechanics of nonlinear coherent\nstructures. To obtain high precision results from numerical calculations, a\ncareful accounting of spacetime discreteness effects is essential, as well as\nthe development of schemes to systematically improve convergence to the\ncontinuum. With a kink-bearing $\\phi^4$ field theory as the application arena,\nwe present such an analysis for a 1+1-dimensional Langevin system. Analytical\npredictions and results from high resolution numerical solutions are found to\nbe in excellent agreement."
    },
    {
        "anchor": "Topology and axions in QCD: QCD axions are at the crossroads of QCD topology and Dark Matter searches. We\npresent here the current status of topological studies on the lattice, and\ntheir implication on axion physics. We outline the specific challenges posed by\nlattice topology, the different proposals for handling them, the observable\neffects of topology on the QCD spectrum and its interrelation with chiral and\naxial symmetries. We review the transition to the Quark Gluon Plasma, the fate\nof topology at the transition, and the approach to the high temperature limit.\nWe discuss the extrapolations needed to reach the regime of cosmological\nrelevance, and the resulting constraints on the QCD axion.",
        "positive": "Numerical Simulations of PT-Symmetric Quantum Field Theories: Many non-Hermitian but PT-symmetric theories are known to have a real\npositive spectrum. Since the action is complex for there theories, Monte Carlo\nmethods do not apply. In this paper the first field-theoretic method for\nnumerical simulations of PT-symmetric Hamiltonians is presented. The method is\nthe complex Langevin equation, which has been used previously to study complex\nHamiltonians in statistical physics and in Minkowski space. We compute the\nequal-time one-point and two-point Green's functions in zero and one dimension,\nwhere comparisons to known results can be made. The method should also be\napplicable in four-dimensional space-time. Our approach may also give insight\ninto how to formulate a probabilistic interpretation of PT-symmetric theories."
    },
    {
        "anchor": "Introduction to Non-perturbative Heavy Quark Effective Theory: Lectures given at the Summer School on \"Modern perspectives in lattice QCD\",\nLes Houches, August 3-28, 2009",
        "positive": "How well do domain wall fermions realize chiral symmetry?: In the domain wall fermion formulation, chiral symmetry breaking in full QCD\nis expected to fall exponentially with the length of the extra dimension. We\nmeasure the chiral symmetry breaking due to a finite extra dimension in two\nways, which can be affected differently by finite volume and explicit fermion\nmass. For quenched QCD the two methods generally agree, except for the largest\nextent of the extra dimension, which makes the limit uncertain. We have less\ndata for full QCD, but see exponential suppression for the method where we have\ndata."
    },
    {
        "anchor": "Excitations of strange bottom baryons: The ground state and first excited state masses of Omega(b) and Omega(bb)\nbaryons are calculated in lattice QCD using dynamical 2+1 flavour gauge fields.\nA set of baryon operators employing different combinations of smeared quark\nfields was used in the framework of the variational method. Results for radial\nexcitation energies were confirmed by carrying out a supplementary\nmultiexponential fitting analysis. Comparison is made with quark model\ncalculations.",
        "positive": "Fermion masses through four-fermion condensates: Fermion masses can be generated through four-fermion condensates when\nsymmetries prevent fermion bilinear condensates from forming. This less\nexplored mechanism of fermion mass generation is responsible for making four\nreduced staggered lattice fermions massive at strong couplings in a lattice\nmodel with a local four-fermion coupling. The model has a massless fermion\nphase at weak couplings and a massive fermion phase at strong couplings. In\nparticular there is no spontaneous symmetry breaking of any lattice symmetries\nin both these phases. Recently it was discovered that in three space-time\ndimensions there is a direct second order phase transition between the two\nphases. Here we study the same model in four space-time dimensions and find\nresults consistent with the existence of a narrow intermediate phase with\nfermion bilinear condensates, that separates the two asymptotic phases by\ncontinuous phase transitions."
    },
    {
        "anchor": "On the Phase Diagram of the SU(2) Adjoint Higgs Model in 2+1 Dimensions: The phase diagram is investigated for SU(2) lattice gauge theory in d=3,\ncoupled to adjoint scalars. For small values of the quartic scalar coupling,\nlambda, the transition separating Higgs and confinement phases is found to be\nfirst-order, in agreement with earlier work by Nadkarni. The surface of\nsecond-order transitions conjectured by Nadkarni, however, is shown instead to\ncorrespond to crossover behaviour. This conclusion is based on a finite size\nanalysis of the scalar mass and susceptibility. The nature of the phase\ntransition at the termination of first-order behaviour is investigated and we\nfind evidence for a critical point at which the scalar mass vanishes. The\nphoton mass and confining string tension are measured and are found to be\nnegligibly small in the Higgs phase. This is correlated with the very small\ndensity of magnetic monopoles in the Higgs phase. The string tension and photon\nmass rise rapidly as the crossover is traversed towards the symmetric phase.",
        "positive": "Phase transitions in center-stabilized lattice gauge theories: We simulate four-dimensional center-stabilized lattice Yang-Mills theories on\nR^3 x S^1 with a newly developed pseudo-heatbath algorithm. We analyze the\nphase structure of such theories, namely the bulk transition and the\nspontaneous breaking of the center symmetry associated with the compact\ndirection."
    },
    {
        "anchor": "Renormalization constants for 2-twist operators in twisted mass QCD: Perturbative and non-perturbative results on the renormalization constants of\nthe fermion field and the twist-2 fermion bilinears are presented with emphasis\non the non-perturbative evaluation of the one-derivative twist-2 vector and\naxial vector operators. Non-perturbative results are obtained using the twisted\nmass Wilson fermion formulation employing two degenerate dynamical quarks and\nthe tree-level Symanzik improved gluon action. The simulations have been\nperformed for pion masses in the range of about 450-260 MeV and at three values\nof the lattice spacing $a$ corresponding to $\\beta=3.9, 4.05, 4.20$.\nSubtraction of ${\\cal O}(a^2)$ terms is carried out by performing the\nperturbative evaluation of these operators at 1-loop and up to ${\\cal O}(a^2)$.\nThe renormalization conditions are defined in the RI$'$-MOM scheme, for both\nperturbative and non-perturbative results. The renormalization factors,\nobtained for different values of the renormalization scale, are evolved\nperturbatively to a reference scale set by the inverse of the lattice spacing.\nIn addition, they are translated to ${\\bar{\\rm MS}}$ at 2 GeV using 3-loop\nperturbative results for the conversion factors.",
        "positive": "Estimating the central charge from the R\u00e9nyi entanglement entropy: We calculate the von Neumann and R\\'enyi bipartite entanglement entropy of\nthe $O(2)$ model with a chemical potential on a 1+1 dimensional Euclidean\nlattice with open and periodic boundary conditions. We show that the\nCalabrese-Cardy conformal field theory predictions for the leading logarithmic\nscaling with the spatial size of these entropies are consistent with a central\ncharge $c=1$. This scaling survives the time continuum limit and truncations of\nthe microscopic degrees of freedom, modifications which allow us to connect the\nLagrangian formulation to quantum Hamiltonians. At half-filling, the forms of\nthe subleading corrections imposed by conformal field theory allow the\ndetermination of the central charge with an accuracy better than two percent\nfor moderately sized lattices. We briefly discuss the possibility of estimating\nthe central charge using quantum simulators."
    },
    {
        "anchor": "Improved gluonic actions on anisotropic lattices: The use of novel perturbatively-improved gluonic actions on anisotropic\nlattices in which the temporal spacing is much smaller than that in the spatial\ndirections is discussed. Such actions permit more efficient measurements of\nnoisy correlation functions, such as glueball correlators, on coarse lattices.\nA derivation of these actions at tree-level is outlined; mean-field link\nrenormalization plays a crucial role in their construction. Results for the\nlow-lying glueball masses and the heavy-quark potential are presented.",
        "positive": "Absolute X-distribution and self-duality: Various models of QCD vacuum predict that it is dominated by excitations that\nare predominantly self-dual or anti-self-dual. In this work we look at the\ntendency for self-duality in the case of pure-glue SU(3) gauge theory using the\noverlap-based definition of the field-strength tensor. To gauge this property,\nwe use the absolute X-distribution method which is designed to quantify the\ndynamical tendency for polarization for arbitrary random variables that can be\ndecomposed in a pair of orthogonal subspaces."
    },
    {
        "anchor": "Quark-Antiquark Forces From SU(2) and SU(3) Gauge Theories on Large\n  Lattices: We present results on the spin-independent quark-antiquark potential in SU(3)\ngauge theory from a simulation on a 48^3*64 lattice at Beta = 6.8,\ncorresponding to a volume of (1.7 fm)^3. Moreover, a comprehensive analysis of\nspin- and velocity-dependent potentials is carried out for SU(2) gauge theory,\nwith emphasis on the short range structure, on lattices with resolutions\nranging from .02 fm to .04 fm.",
        "positive": "Comparing lattice Dirac operators with Random Matrix Theory: We study the eigenvalue spectrum of different lattice Dirac operators\n(staggered, fixed point, overlap) and discuss their dependence on the\ntopological sectors. Although the model is 2D (the Schwinger model with\nmassless fermions) our observations indicate possible problems in 4D\napplications. In particular misidentification of the smallest eigenvalues due\nto non-identification of the topological sector may hinder successful\ncomparison with Random Matrix Theory (RMT)."
    },
    {
        "anchor": "Two-color QCD with staggered fermions at finite temperature under the\n  influence of a magnetic field: In this paper we investigate the influence of a constant external magnetic\nfield on the finite-temperature phase structure and the chiral properties of a\nsimplified lattice model for QCD. We assume an SU(2) gauge symmetry and employ\ndynamical staggered fermions of identical mass without rooting, corresponding\nto Nf=4 flavors of identical electric charge. For fixed mass (given in lattice\nunits) the critical temperature is seen to rise with the magnetic field\nstrength. For three fixed beta-values, selected such that we stay (i) within\nthe chirally broken phase, (ii) within the transition region or (iii) within\nthe chirally restored phase, we study the approach to the chiral limit for\nvarious values of the magnetic field. Within the chirally broken (confinement)\nphase the chiral condensate is found to increase monotonically with a growing\nmagnetic field strength. In the chiral limit the increase starts linear in\nagreement with a chiral model studied by Shushpanov and Smilga. Within the\nchirally restored (deconfinement) phase the chiral condensate tends to zero in\nthe chiral limit, irrespective of the strength of the magnetic field.",
        "positive": "Thermal momentum distribution from path integrals with shifted boundary\n  conditions: For a thermal field theory formulated in the grand canonical ensemble, the\ndistribution of the total momentum is an observable characterizing the thermal\nstate. We show that its cumulants are related to thermodynamic potentials. In a\nrelativistic system for instance, the thermal variance of the total momentum is\na direct measure of the enthalpy. We relate the generating function of the\ncumulants to the ratio of (a) a partition function expressed as a Matsubara\npath integral with shifted boundary conditions in the compact direction, and\n(b) the ordinary partition function. In this form the generating function is\nwell suited for Monte-Carlo evaluation, and the cumulants can be extracted\nstraightforwardly. We test the method in the SU(3) Yang-Mills theory and obtain\nthe entropy density at three different temperatures."
    },
    {
        "anchor": "Lattice QCD study of static quark and antiquark correlations via\n  entanglement entropies: We study the color correlation between static quark and antiquark ($q\\bar q$)\nin the confined phase via reduced density matrices $\\rho$ defined in color\nspace. We adopt the standard Wilson gauge action and perform quenched\ncalculations with the Coulomb gauge condition for reduced density matrices. The\nspatial volumes are $L^3 = 8^3$, $16^3$, $32^3$ and $48^3$, with the gauge\ncouplings $\\beta = 5.7$, 5.8 and 6.0. Each element of the reduced density\nmatrix in the sub space of quarks' color degrees of freedom of the $q\\bar q$\npair is calculated from staples defined by link variables. As a result, we find\nthat $\\rho$ is well written by a linear combination of the strongly correlated\n$q\\bar q$ pair state with the color-singlet component and the uncorrelated\n$q\\bar q$ pair state with random color configurations. We compute the Renyi\nentropies $S^{\\rm Renyi}$ from $\\rho$ to investigate the $q\\bar q$ distance\ndependence of the color correlation of the $q\\bar q$ pair and find that the\ncolor correlation is quenched as the distance increases.",
        "positive": "Can baryogenesis occur on the lattice?: We examine the question of how baryogenesis can occur in lattice models of\nthe Standard Model where there is a global $U(1)$ symmetry which is accompanied\nby an exactly conserved fermion number. We demonstrate that fermion creation\nand annihilation can occur in these models {\\em despite} this exact fermion\nnumber conservation, by explicitly computing the spectral flow of the\nhamiltonian in the two dimensional U(1) axial model with Wilson fermions. For\ncomparison we also study the closely related Schwinger model where a similar\nmechanism gives rise to anomalous particle creation and annihilation."
    },
    {
        "anchor": "QCD with two dynamical flavors of chirally improved quarks: Considering Ginsparg-Wilson type fermions dynamically in lattice QCD\nsimulations is a challenging task. The hope is to be able to approach smaller\npion masses and to eventually reach physical situations. The price to pay is\nsubstantially higher computational costs. Here we discuss first results of a\ndynamical implementation of the so-called Chirally Improved Fermions, a Dirac\noperator that obeys the Ginsparg-Wilson condition approximately. The simulation\nis for two species of mass-degenerate quarks on 12^3x24 lattices with spatial\nsize up to 1.55 fm. Implementation of the Hybrid Monte-Carlo algorithm and an\nanalysis of the results are presented.",
        "positive": "Long-range electroweak amplitudes of single hadrons from Euclidean\n  finite-volume correlation functions: A relation is presented between single-hadron long-range matrix elements\ndefined in a finite Euclidean spacetime, and the corresponding infinite-volume\nMinkowski amplitudes. This relation is valid in the kinematic region where any\nnumber of two-hadron states can simultaneously go on shell, so that the effects\nof strongly-coupled intermediate channels are included. These channels can\nconsist of non-identical particles with arbitrary intrinsic spins. The result\naccommodates general Lorentz structures as well as non-zero momentum transfer\nfor the two external currents inserted between the single-hadron states. The\nformalism, therefore, generalizes the work by Christ et al.~[Phys.Rev. D91\n114510 (2015)], and extends the reach of lattice quantum chromodynamics (QCD)\nto a wide class of new observables beyond meson mixing and rare decays.\nApplications include Compton scattering of the pion ($\\pi \\gamma^\\star \\to [\\pi\n\\pi, K \\overline K] \\to \\pi \\gamma^\\star$), kaon ($K \\gamma^\\star \\to [\\pi K,\n\\eta K] \\to K \\gamma^\\star$) and nucleon ($N \\gamma^\\star \\to N \\pi \\to N\n\\gamma^\\star$), as well as double-$\\beta$ decays, and radiative corrections to\nthe single-$\\beta$ decay, of QCD-stable hadrons. The framework presented will\nfurther facilitate generalization of the result to studies of nuclear\namplitudes involving two currents from lattice QCD."
    },
    {
        "anchor": "Overlap/Domain-wall reweighting: We investigate the eigenvalues of nearly chiral lattice Dirac operators\nconstructed with five-dimensional implementations. Allowing small violation of\nthe Ginsparg-Wilson relation, the HMC simulation is made much faster while the\neigenvalues are not significantly affected. We discuss the possibility of\nreweighting the gauge configurations generated with domain-wall fermions to\nthose of exactly chiral lattice fermions.",
        "positive": "On the Measure of Simplicial Quantum Gravity in Four Dimensions: We study quantum gravity in the path-integral formulation using the Regge\ncalculus. In spite of the unbounded gravitational action the existence of an\nentropy-dominated phase is confirmed. The influence of various types of\nmeasures on this phase structure is investigated and our results are compared\nwith those obtained by dynamical triangulation."
    },
    {
        "anchor": "Meson masses and decay constants from unquenched lattice QCD: We report results for the masses of the flavour non-singlet light 0++, 1--,\nand 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted\nmass formalism was used with two flavours of sea quarks. For the 0++ and 1+-\nmesons we look for the effect of decays on the mass dependence. For the light\nvector mesons we study the chiral extrapolations of the mass. We report results\nfor the leptonic and transverse decay constants of the rho meson. We test the\nmass dependence of the KRSF relations.",
        "positive": "Testing importance sampling on a quantum annealer for strong coupling\n  SU(3) gauge theory: $SU(N_c)$ gauge theories in the strong coupling limit can be described by\ninteger variables representing monomers, dimers and baryon loops. We\ndemonstrate how the D-wave quantum annealer can perform importance sampling on\n$U(N_c)$ gauge theory in the strong coupling formulation of this theory. In\naddition to causing a sign problem in importance sampling, baryon loops induce\na complex QUBO matrix which cannot be optimized by the D-Wave annealer. Instead\nwe show that simulating the sign-problem free quenched action on the D-Wave is\nsufficient when combined with a sign reweighting method. As the first test on\n$SU(3)$ gauge theory, we simulate on $2 \\times 2$ lattice and compare the\nresults with its analytic solutions."
    },
    {
        "anchor": "Breaking the gauge symmetry in lattice gauge-invariant models: We consider the role that gauge symmetry breaking terms play on the continuum\nlimit of gauge theories in three dimensions. As a paradigmatic example we\nconsider scalar electrodynamics in which $N_f$ complex scalar fields interact\nwith a U(1) gauge field. We discuss under which conditions a gauge-symmetry\nbreaking term destabilizes the critical behavior (continuum limit) of the\ngauge-invariant theory. We find that the gauge symmetry is robust at\ntransitions at which gauge fields are not critical. At charged transitions,\nwhere gauge fields are critical, gauge symmetry is lost as soon as the\nperturbation is added.",
        "positive": "Effective Field Theory for the Anisotropic Wilson Lattice Action: We construct the effective field theory appropriate for describing the low\nenergy behavior of anisotropic Wilson lattice actions and the O(a) improved\nvariant thereof. We then apply this effective field theory to the hadron\nspectrum and dispersion relations, focussing on the corrections due to the\nanisotropy. We point out an important feature of anisotropic lattices regarding\nthe Aoki-regime; for a given set of fermion masses and spatial lattice spacing,\nif an isotropic action is in the QCD-phase, this does not guarantee that the\nanisotropic action is outside the Aoki-regime. This may be important in the\ntuning of bare parameters for anisotropic lattices using domain-wall and\noverlap fermions as well as Wilson and O(a)-improved Wilson fermions."
    },
    {
        "anchor": "Nucleon Masses and Magnetic Moments in a Finite Volume: We compute finite-size corrections to nucleon masses and magnetic moments in\na periodic, spatial box of size L, both in QCD and in partially-quenched QCD.",
        "positive": "Lattice QCD results on soft and hard probes of strongly interacting\n  matter: We present recent results from lattice QCD relevant for the study of strongly\ninteracting matter as it is produced in heavy ion collision experiments. The\nequation of state at non-vanishing density from a Taylor expansion up to\n$6^{th}$ order will be discussed for a strangeness neutral system and using the\nexpansion coefficients of the series limits on the critical point are\nestimated. Chemical freeze-out temperatures from the STAR and ALICE\nCollaborations will be compared to lines of constant physics calculated from\nthe Taylor expansion of QCD bulk thermodynamic quantities. We show that\nqualitative features of the $\\sqrt{s_{NN}}$ dependence of skewness and kurtosis\nratios of net proton-number fluctuations measured by the STAR Collaboration can\nbe understood from QCD results for cumulants of conserved baryon-number\nfluctuations. As an example for recent progress towards the determination of\nspectral and transport properties of the QGP from lattice QCD, we will present\nconstraints on the thermal photon rate determined from a spectral\nreconstruction of continuum extrapolated lattice correlation functions in\ncombination with input from most recent perturbative calculations."
    },
    {
        "anchor": "Toward an analytic determination of the deconfinement temperature in\n  SU(2) L.G.T.: We consider the SU(2) lattice gauge theory at finite temperature in (d+1)\ndimensions, with different couplings $\\beta_t$ and $\\beta_s$ for timelike and\nspacelike plaquettes. By using the character expansion of the Wilson action and\nperforming the integrals over space-like link variables, we find an effective\naction for the Polyakov loops which is exact to all orders in $\\beta_t$ and to\nthe first non-trivial order in $\\beta_s$. The critical coupling for the\ndeconfinement transition is determined in the (3+1) dimensional case, by the\nmean field method, for different values of the lattice size $N_t$ in the\ncompactified time direction and of the asymmetry parameter $\\rho =\n\\sqrt{\\beta_t/\\beta_s}$. We find good agreement with Montecarlo simulations in\nthe range $1\\leq N_t \\leq 5$, and good qualitative agreement in the same range\nwith the logarithmic scaling law of QCD. Moreover the dependence of the results\nfrom the parameter $\\rho$ is in excellent agreement with previous theoretical\npredictions.",
        "positive": "What Lattice QCD tell us about the Landau Gauge Infrared Propagators: The calculation of the Landau gauge gluon propagator performed in Coimbra\nusing lattice QCD simulations is reviewed. Particular attention is given to the\nbehavior of the gluon propagator in the infrared region and the value of\n$D(0)$. In the second part of the article, the modeling of the lattice data\nusing massive type propagators and Gribov type propagators is discussed. Four\ndifferent mass scales are required to describe the propagator over the full\nrange of momenta accessed by the simulations discussed here. Furthermore,\nassuming a momentum dependent gluon mass, we sketch on its functional\ndependence."
    },
    {
        "anchor": "Introduction to Lattice QCD: These notes aim to provide a pedagogical introduction to Lattice QCD. The\ntopics covered include the scope of LQCD calculations, lattice discretization\nof gauge and fermion (naive, Wilson, and staggered) actions, doubling problem,\nimproved gauge and Dirac actions, confinement and strong coupling expansions,\nphase transitions in the lattice theory, lattice operators, a general\ndiscussion of statistical and systematic errors in simulations of LQCD, the\nanalyses of the hadron spectrum, glueball masses, the strong coupling constant,\nand the quark masses.",
        "positive": "Finite temperature gluon spectral functions from $N_f=2+1+1$ lattice QCD: We investigate gluon spectral functions at finite temperature in Landau\ngauge, based on a subset of lattice QCD ensembles with $N_f=2+1+1$ dynamical\ntwisted mass quarks flavors, generated by the tmfT collaboration. Our study\nuses a novel Bayesian approach for the extraction of non-positive definite\nspectral functions, which for each binned spatial momentum takes into account\nthe gluon correlation functions at all available discrete imaginary\nfrequencies. The spectral functions are extracted at three different lattice\nspacing, where for each of them, a scan of temperatures around the crossover\ntransition is carried out at fixed scale. We find indications for the existence\nof a well defined quasi-particle peak. Due to a relatively small number of\nimaginary frequencies available, we focus on the momentum and temperature\ndependence of the position of this spectral feature. This dispersion relation\nreveals different in-medium masses for longitudinal and transversal gluons at\nhigh temperatures, qualitatively consistent with weak coupling expectations."
    },
    {
        "anchor": "Chirally improved Dirac operators: Studying the sensitivity to\n  topological excitations for zero and finite temperature: We discuss the construction and properties of an approximate solution of the\nGinsparg-Wilson equation, the so-called chirally improved lattice Dirac\noperator. In particular we study the behavior of its eigenmodes in smooth\ninstanton backgrounds as well as for thermalized gauge configurations on both\nsides of the QCD phase transition. We compare with results from other Dirac\noperators including the overlap operator. The results support the picture of\nchiral symmetry breaking being closely related to instantons.",
        "positive": "QCDGPU: open-source package for Monte Carlo lattice simulations on\n  OpenCL-compatible multi-GPU systems: The multi-GPU open-source package QCDGPU for lattice Monte Carlo simulations\nof pure SU(N) gluodynamics in external magnetic field at finite temperature and\nO(N) model is developed. The code is implemented in OpenCL, tested on AMD and\nNVIDIA GPUs, AMD and Intel CPUs and may run on other OpenCL-compatible devices.\nThe package contains minimal external library dependencies and is OS\nplatform-independent. It is optimized for heterogeneous computing due to the\npossibility of dividing the lattice into non-equivalent parts to hide the\ndifference in performances of the devices used. QCDGPU has client-server part\nfor distributed simulations. The package is designed to produce lattice gauge\nconfigurations as well as to analyze previously generated ones. QCDGPU may be\nexecuted in fault-tolerant mode. Monte Carlo procedure core is based on PRNGCL\nlibrary for pseudo-random numbers generation on OpenCL-compatible devices,\nwhich contains several most popular pseudo-random number generators."
    },
    {
        "anchor": "B-meson physics from non-perturbative lattice heavy quark effective\n  theory: During the last years, the ALPHA collaboration has been developing and\nimplementing a method based on Heavy Quark Effective Theory (HQET) to compute\nB-mesons observables through lattice simulations. Thanks to a non-perturbative\nmatching to QCD, the theory is renormalizable at any order of the heavy quark\nmass expansion. In order to extract precisely the relevant matrix elements and\nmasses, we use all-to-all propagators and solve an generalized eigenvalue\nproblem (GEVP). We have shown in the quenched approximation that quantities\nlike the b-quark mass mb, the heavy-light decay constant(s) or the B-meson\nspectrum can be computed precisely beyond the static approximation (including\nthe first corrections in 1/\\mb). More recently, we have started to include the\nsea quark effects, by working with Nf=2 light flavors of dynamical fermions[1].\nThe computation of the matching parameters is almost finished, but concerning\nthe extraction of the hadronic quantities for which we use some CLS\nensembles[2], only one lattice spacing has been analyzed so far. In this\nproceeding we report on the status of this project and present some preliminary\nresults.",
        "positive": "Ordering monomial factors of polynomials in the product representation: The numerical construction of polynomials in the product representation (as\nused for instance in variants of the multiboson technique) can become\nproblematic if rounding errors induce an imprecise or even unstable evaluation\nof the polynomial. We give criteria to quantify the effects of these rounding\nerrors on the computation of polynomials approximating the function $1/s$. We\nconsider polynomials both in a real variable $s$ and in a Hermitian matrix. By\ninvestigating several ordering schemes for the monomials of these polynomials,\nwe finally demonstrate that there exist orderings of the monomials that keep\nrounding errors at a tolerable level."
    },
    {
        "anchor": "Precision computation of the kaon bag parameter: Indirect CP violation in K \\rightarrow {\\pi}{\\pi} decays plays a central role\nin constraining the flavor structure of the Standard Model (SM) and in the\nsearch for new physics. For many years the leading uncertainty in the SM\nprediction of this phenomenon was the one associated with the nonperturbative\nstrong interaction dynamics in this process. Here we present a fully controlled\nlattice QCD calculation of these effects, which are described by the neutral\nkaon mixing parameter B_K . We use a two step HEX smeared clover-improved\nWilson action, with four lattice spacings from a\\approx0.054 fm to\na\\approx0.093 fm and pion masses at and even below the physical value.\nNonperturbative renormalization is performed in the RI-MOM scheme, where we\nfind that operator mixing induced by chiral symmetry breaking is very small.\nUsing fully nonperturbative continuum running, we obtain our main result\nB_K^{RI}(3.5GeV)=0.531(6)_{stat}(2)_{sys}. A perturbative 2-loop conversion\nyields B_K^{MSbar-NDR}(2GeV)=0.564(6)_{stat}(3)_{sys}(6)_{PT}, which is in good\nagreement with current results from fits to experimental data.",
        "positive": "Chiral anomalies in the reduced model: On the basis of an observation due to Kiskis, Narayanan and Neuberger, we\nshow that there is a remnant of chiral anomalies in the reduced model when a\nDirac operator which obeys the Ginsparg-Wilson relation is employed for the\nfermion sector. We consider fermions belonging to the fundamental\nrepresentation of the gauge group U(N) or SU(N). For vector-like theories, we\ndetermine a general form of the axial anomaly or the topological charge within\na framework of a U(1) embedding. For chiral gauge theories with the gauge group\nU(N), a remnant of gauge anomaly emerges as an obstruction to a smooth fermion\nintegration measure. The pure gauge action of gauge-field configurations which\ncause these non-trivial phenomena always diverges in the 't Hooft $N\\to\\infty$\nlimit when d>2."
    },
    {
        "anchor": "Study of the effects of external imaginary electric field and chiral\n  chemical potential on quark matter: The behavior of quark matter with both external electric field and chiral\nchemical potential is theoretically and experimentally interesting to consider.\nIn this paper, the case of simultaneous presence of imaginary electric field\nand chiral chemical potential is investigated using the lattice QCD approach\nwith $N_f=1+1$ dynamical staggered fermions. We find that overall both the\nimaginary electric field and the chiral chemical potential can exacerbate\nchiral symmetry breaking, which is consistent with theoretical predictions.\nHowever we also find a non-monotonic behavior of chiral condensation at\nspecific electric field strengths and chiral chemical potentials. In addition\nto this, we find that the behavior of Polyakov loop in the complex plane is not\nsignificantly affected by chiral chemical potential in the region of the\nparameters consider in this paper.",
        "positive": "Distribution of Canonical Determinants in QCD: The distribution of canonical determinants in QCD is determined by means of\nchiral perturbation theory. For a non-zero quark charge the canonical\ndeterminants take complex values. In the dilute pion gas approximation, we\ncompute all moments of the magnitude of the canonical determinants, as well as\nthe first nonvanishing moments of the real and imaginary parts. The non-trivial\ncancellation between the real and the imaginary parts of the canonical\ndeterminants is derived and the signal to noise ratio is discussed. The\nanalytical distributions are compared to lattice data. The average density of\nthe magnitude of the canonical determinants is determined as well and is shown\nto be given by a variant of the log-normal distribution."
    },
    {
        "anchor": "The generalized fermion-bag approach: We present a new approach to some four-fermion lattice field theories which\nwe call the generalized fermion bag approach. The basic idea is to identify\nunpaired fermionic degrees of freedom that cause sign problems and collect them\nin a bag. Paired fermions usually act like bosons and do not lead to sign\nproblems. A resummation of all unpaired fermion degrees of freedom inside the\nbag is sufficient to solve the fermion sign problem in a variety of interesting\ncases. Using a concept of duality we then argue that the size of the fermion\nbags is small both at strong and weak couplings. This allows us to construct\nefficient algorithms in both these limits. Using the fermion bag approach, we\nstudy the quantum phase transition of the 3D massless lattice Thirrring model\nwhich is of interest in the context of Graphene. Using our method we are able\nto solve the model on lattices as large as $40^3$ with moderate computational\nresources. We obtain the precise location of the quantum critical point and the\nvalues of the critical exponents through this study.",
        "positive": "Spin-2 $N\u03a9$ Dibaryon from Lattice QCD: We investigate properties of the $N$(nucleon)-$\\Omega$(Omega) interaction in\nlattice QCD to seek for possible dibaryon states in the strangeness $-3$\nchannel. We calculate the $N\\Omega$ potential through the equal-time\nNambu-Bethe-Salpeter wave function in 2+1 flavor lattice QCD with the\nrenormalization group improved Iwasaki gauge action and the nonperturbatively\n$\\mathcal{O}(a)$ improved Wilson quark action at the lattice spacing $a\\simeq\n0.12$ fm on a (1.9 fm)$^{3}\\times$ 3.8 fm lattice. The $ud$ and $s$ quark\nmasses in our study correspond to $m_{\\pi}= 875(1)$ MeV and $m_{K}= 916(1)$\nMeV. At these parameter values, the central potential in the S-wave with the\nspin 2 shows attractions at all distances.By solving the Schr\\\"{o}dinger\nequation with this potential, we find one bound state whose binding energy is\n$18.9(5.0)(^{+12.1}_{-1.8})$ MeV, where the first error is the statistical one,\nwhile the second represents the systematic error."
    },
    {
        "anchor": "Bosonization and the lattice: the $d=2$ Gross-Neveu model: We consider the lattice formulation of bosonized quantum field theories. As a\nnon trivial example, we study the two dimensional Gross-Neveu model. Analytical\ninvestigations and direct numerical simulation strongly suggest that the\nlattice model reproduces the continuum physics. Anticommuting fields are not\nrequired and there are not related doubling problems. (3 PostScript figures\navailable from the author)",
        "positive": "QCD topology and axion's properties from Wilson twisted mass lattice\n  simulations: We present the results on topological susceptibility and chiral observables\nin $N_f=2+1+1$ QCD for temperature range $120<T<600$ MeV. The lattice\nsimulations are performed with Wilson twisted mass fermions at physical pion,\nstrange and charm masses. In high-$T$ region $T\\gtrsim 300$ MeV the chiral\nobservables are shown to follow leading order Griffith analyticity, and the\ntopological susceptibility follows a power-law decay as in the instanton dilute\ngas models. The measured topological susceptibility is used to estimate the\nmass of QCD axion. The resulting axion mass constraints are in agreement with\nour previous studies at higher pion masses."
    },
    {
        "anchor": "Further results on O(a) improved lattice QCD to one-loop order of\n  perturbation theory: We present results at one-loop order of perturbation theory for various\nimprovement coefficients in on-shell O($a$) improved lattice QCD. In particular\nwe determine the additive counterterm required for on-shell improvement of the\nisovector vector current. Employing a general mass-independent renormalization\nscheme we also obtain the coefficients of the O($a$) counterterms which are\nproportional to the quark mass in the improved isovector pseudo-scalar, axial\nvector and vector operators. In the latter case a comparison with a recent\nnon-perturbative study is made.",
        "positive": "Determination of $m_c$ from $N_f = 2+1$ QCD with Wilson fermions: We present preliminary results for the charm quark mass in the $N_f=4$ RGI\nscheme. These were obtained using $N_f=2+1$ CLS ensembles with $\\mathcal{O}(a)$\nnon-perturbatively improved Wilson fermions. We employed five different lattice\nspacings, ranging down to $a\\lesssim 0.04$ fm and realized approximately\nphysical pion and kaon masses, with ensembles spread out along three different\ntrajectories in the quark mass plane, enabling a thorough study of the\ndependence on the lattice spacing and the light and strange sea quark masses.\nWe sketch our analysis strategy and find that the dominant errors at present\nare due to the renormalization and scale setting uncertainties."
    },
    {
        "anchor": "Static quark-antiquark potential and Dirac eigenvector correlators: We represent the Polyakov loop correlator as a spectral sum of correlators of\neigenvectors of the lattice Dirac operator. This spectral representation is\nstudied numerically using quenched SU(3) configurations below and above the\ndeconfinement temperature. We analyze whether the individual Dirac eigenvector\ncorrelators differ in the confined and deconfined phases. The decay properties\nof the normalized Dirac eigenvector correlators turn out to be essentially\nidentical in the two phases, but the amplitudes change. This change of the\namplitudes shifts the relative contributions of the individual Dirac\neigenvector correlators and is the driving mechanism for the transition from\nthe confining static potential into the deconfining one.",
        "positive": "Perturbative computation in a QED$_3$-inspired conformal abelian gauge\n  model on the lattice: We perform perturbative computations in a lattice gauge theory with a\nconformal measure that is quadratic in a non-compact abelian gauge field and is\nnonlocal, as inspired by the induced gauge action in massless QED$_3$. In a\nprevious work, we showed that coupling fermion sources to the gauge model led\nto nontrivial conformal data in the correlation functions of fermion bilinears\nthat are functions of charge $q$ of the fermion. In this paper, we compute such\ngauge invariant fermionic observables to order $q^2$ in lattice perturbation\ntheory with the same conformal measure. We reproduce the expectations for\nscalar anomalous dimension from previous estimates in dimensional\nregularization. We address the issue of the lattice regulator dependence of the\namplitudes of correlation functions."
    },
    {
        "anchor": "Strange and charm meson masses from twisted mass lattice QCD: We present first results of a 2+1+1 flavor twisted mass lattice QCD\ncomputation of strange and charm meson masses. We focus on D and D_s mesons\nwith spin J = 0,1 and parity P = -,+.",
        "positive": "Progress in hadron structure physics on the lattice: This is a review of progress in hadron structure physics from lattice QCD.\nRecent results on the structure of the nucleon and the pion in terms of\n(transition) form factors, moments of distribution amplitudes and (generalized)\nparton distribution functions are presented. These observables allow us to\ninvestigate a number of fundamental physics questions related to e.g. the\ndistribution of charge and momentum in hadrons, the spin structure of the\nnucleon and the pion, and correlations between spin, orbital angular momentum\nand coordinate degrees of freedom. Chiral extrapolations of selected lattice\nresults are presented and compared to results from experiment and\nphenomenology. We conclude that lattice simulations already today strongly\ncontribute to our understanding of the structure of hadrons."
    },
    {
        "anchor": "String Breaking in SU(2) Yang Mills Theory with Adjoint Sources: We compute the static potential in three-dimensional SU(2) Yang Mills Theory\nwith adjoint sources using numerical simulations. By employing a variational\napproach involving string and gluelump operators, we obtain clear evidence for\nstring breaking in the adjoint potential. The breaking scale r_b is computed\nand extrapolated to the continuum limit. The result in units of the scalar\nglueball mass is r_b*m_G = 10.3 +/- 1.5. We also resolve the structure of\nhigher excitations of the flux-tube and gluelumps. Furthermore we discuss the\nimplications of our findings for the case of the four-dimensional theory.",
        "positive": "Accurate exponents from approximate tensor renormalizations: We explain the recent numerical successes obtained by Tao Xiang's group, who\ndeveloped and applied Tensor Renormalization Group methods for the Ising model\non square and cubic lattices, by the fact that their new truncation method\nsharply singles out a surprisingly small subspace of dimension two. We show\nthat in the two-state approximation, their transformation can be handled\nanalytically yielding a value 0.964 for the critical exponent nu much closer to\nthe exact value 1 than 1.338 obtained in the Migdal-Kadanoff approximation. We\npropose two alternative blocking procedures that preserve the isotropy and\nimprove the accuracy to nu=0.987 and 0.993 respectively. We discuss\napplications to other classical lattice models, including models with fermions,\nand suggest that it could become a competitor for Monte Carlo methods suitable\nto calculate accurately critical exponents, take continuum limits and study\nnear-conformal systems in arbitrarily large volumes."
    },
    {
        "anchor": "Decimation map in 2D for accelerating HMC: To accelerate the HMC with field transformation, we consider a variant of the\ntrivializing map, the decimation map, which can be regarded as a\ncoarse-graining transformation. Using the 2D $U(1)$ pure gauge model, combined\nwith the guided Monte Carlo algorithm, we show that the integrated\nautocorrelation time of the topological charge can be exponentially improved in\nthe wall clock time. Our study indicates that incorporating renormalization\ngroup picture is a powerful and essential ingredient to accelerate the HMC at\nlarge $\\beta$.",
        "positive": "Lattice chiral symmetry, CP-violation and Majorana fermions: A brief summary of lattice fermions defined by the general Ginsparg-Wilson\nalgebra is first given. It is then shown that those general class of fermion\noperators have a conflict with CP invariance in chiral gauge theory and with\nthe definition of Majorana fermions in the presence of chiral-symmetric Yukawa\ncouplings. The same conclusion holds for the domain-wall fermion also."
    },
    {
        "anchor": "Meron-cluster algorithms and chiral symmetry breaking in a (2+1)-d\n  staggered fermion model: The recently developed Meron-Cluster algorithm completely solves the\nexponentially difficult sign problem for a number of models previously\ninaccessible to numerical simulation. We use this algorithm in a high-precision\nstudy of a model of N=1 flavor of staggered fermions in (2+1)-dimensions with a\nfour-fermion interaction. This model cannot be explored using standard\nalgorithms. We find that the Z(2) chiral symmetry of this model is\nspontaneously broken at low temperatures and that the finite-temperature chiral\nphase transition is in the universality class of the 2-d Ising model, as\nexpected.",
        "positive": "Lattice study of infrared behaviour in SU(3) gauge theory with twelve\n  massless flavours: We present details of a lattice study of infrared behaviour in SU(3) gauge\ntheory with twelve massless fermions in the fundamental representation. Using\nthe step-scaling method, we compute the coupling constant in this theory over a\nlarge range of scale. The renormalisation scheme in this work is defined by the\nratio of Polyakov loops in the directions with different boundary conditions.\nWe closely examine systematic effects, and find that they are dominated by\nerrors arising from the continuum extrapolation. Our investigation suggests\nthat SU(3) gauge theory with twelve flavours contains an infrared fixed point."
    },
    {
        "anchor": "Explorations beyond dilaton chiral perturbation theory in the\n  eight-flavor SU(3) gauge theory: We continue our study of spectroscopy data for the SU(3) gauge theory with\neight fundamental fermions, motivated by the effective field theory framework\nof dilaton chiral perturbation theory (dChPT). At leading order dChPT predicts\na constant mass anomalous dimension $\\gamma_m$, consistent with the assumed\nproximity of an infrared fixed point. For the relatively large fermion masses\nsimulated by the LatKMI collaboration, the influence of the infrared fixed\npoint diminishes, and our fits suggest that $\\gamma_m$ starts running. Since a\ncomplete higher-order analysis is not feasible with presently available data,\nwe adopt a more phenomenological approach. We propose a partial extension to\nhigher orders, which incorporates the running of $\\gamma_m$ into the tree-level\nlagrangian. We find that this extension successfully describes the full\nfermion-mass range of the LatKMI data, including the pion taste splittings\nwhich arise from using staggered fermions in the lattice simulations. We also\ninvestigate a more general class of dilaton potentials proposed in the\nliterature, using both the LSD and LatKMI data sets, concluding that these data\nfavor the form predicted by dChPT.",
        "positive": "Neutral kaon mixing from new physics: matrix elements in $N_f=2+1$ QCD: We present results for matrix elements of $\\Delta S=2$ four-fermion operators\narising generically in models of new physics. These are needed to constrain\nsuch models using the measured values of $\\varepsilon_K$ and $\\Delta M_K$. We\nuse lattice QCD with 2+1 flavors of improved staggered fermions on lattices\ngenerated by the MILC collaboration. We extrapolate to the continuum from three\nlattice spacings ranging down to $a\\approx 0.045\\;$fm. Total errors are $\\sim\n5-6%$, arising primarily from our use of one-loop matching between lattice and\ncontinuum operators. For two of the matrix elements, our results disagree\nsignificantly from those obtained using different fermion discretizations."
    },
    {
        "anchor": "Probing the Region of Massless Quarks in Quenched Lattice QCD using\n  Wilson Fermions: We study the spectrum of $H(m)=\\gamma_5 W(-m)$ with $W(m)$ being the\nWilson-Dirac operator on the lattice with bare mass equal to $m$. The\nbackground gauge fields are generated using the SU(3) Wilson action at\n$\\beta=5.7$ on an $8^3\\times 16$ lattice. We find evidence that the spectrum of\n$H(m)$ is gapless for $1.02 < m < 2.0$, implying that the physical quark is\nmassless in this whole region.",
        "positive": "Nonperturbative beta function of eight-flavor SU(3) gauge theory: We present a new lattice study of the discrete beta function for SU(3) gauge\ntheory with Nf=8 massless flavors of fermions in the fundamental\nrepresentation. Using the gradient flow running coupling, and comparing two\ndifferent nHYP-smeared staggered lattice actions, we calculate the 8-flavor\nstep-scaling function at significantly stronger couplings than were previously\naccessible. Our continuum-extrapolated results for the discrete beta function\nshow no sign of an IR fixed point up to couplings of g^2~14. At the same time,\nwe find that the gradient flow coupling runs much more slowly than predicted by\ntwo-loop perturbation theory, reinforcing previous indications that the\n8-flavor system possesses nontrivial strongly coupled IR dynamics with\nrelevance to BSM phenomenology."
    },
    {
        "anchor": "The rooting issue for a lattice fermion formulation similar to staggered\n  fermions but without taste mixing: To investigate the viability of the 4th root trick for the staggered fermion\ndeterminant in a simpler setting, we consider a two taste (flavor) lattice\nfermion formulation with no taste mixing but with exact taste-nonsinglet chiral\nsymmetries analogous to the taste-nonsinglet $U(1)_A$ symmetry of staggered\nfermions. M. Creutz's objections to the rooting trick apply just as much in\nthis setting. To counter them we show that the formulation has robust would-be\nzero-modes in topologically nontrivial gauge backgrounds, and that these\nmanifest themselves in a viable way in the rooted fermion determinant and also\nin the disconnected piece of the pseudoscalar meson propagator as required to\nsolve the U(1) problem. Also, our rooted theory is heuristically seen to be in\nthe right universality class for QCD if the same is true for an unrooted mixed\nfermion action theory.",
        "positive": "A Lattice Calculation of the Heavy Quark Universal Form Factor: A computation of the Isgur-Wise universal form factor using a lattice\nimplementation of the heavy quark effective theory is described, and the\nresults of a lattice simulation are presented."
    },
    {
        "anchor": "Non-lattice simulation of supersymmetric gauge theories as a probe to\n  quantum black holes and strings: In the past decade we have witnessed remarkable developments in the\ngauge-gravity duality, which suggested a new approach to superstring theory and\nquantum space-time. In this context it is important to study supersymmetric\nlarge-N gauge theories in the strongly coupled regime. I will summarize the\nresults and insights obtained so far by non-lattice simulations. A simple\nexample of the gauge-gravity duality is the one between 1d U(N) gauge theory\nwith 16 supercharges and the so-called black 0-brane solution in type IIA\nsupergravity. In order for this duality to be valid, one has to take the 't\nHooft large-N limit and to take the strong coupling limit on the gauge theory\nside. The gauge theory can be regularized by fixing the gauge completely thanks\nto one dimension, and by introducing a Fourier mode cutoff. One can then use\nthe standard RHMC algorithm to simulate the system. The energy calculated as a\nfunction of the temperature was compared with the results obtained from the\ngravity side based on the black hole thermodynamics. This confirmed the\ngauge-gravity duality with high accuracy and provided the microscopic origin of\nthe black hole thermodynamics. From the calculation of the Wilson loop, one\nobtains the Schwarzschild radius of the dual geometry. One can actually use the\npresent 1d model with supersymmetric mass deformation to study \\mathcal{N}=4\nsuper Yang-Mills theory on R \\times S^3 based on a novel large-N reduction,\nwhich generalizes the original idea of Eguchi and Kawai. It is remarkable that\nwe can now simulate the 4d superconformal field theory, which appears in the\nmost typical case of the gauge-gravity duality known as the AdS/CFT\ncorrespondence. In particular, no fine-tuning is required unlike previous\nproposals based on the lattice regularization.",
        "positive": "Chiral structure of the solutions of the Ginsparg-Wilson relation: We analyse the structure of solutions of the Ginsparg-Wilson relation for\nlattice Dirac operator in topologically trivial gauge sector. We show that the\nproperties of such solutions relating to the perturbative stability of the pole\nof the fermion propagator as well as to the structure of the Yukawa models\nbased on these solutions are solely determined by the non-local chirally\ninvariant part of these Dirac operators. Depending on the structure of this\npart, the pole in the fermion propagator may or may not be stable under\nradiative corrections. We illustrate this by explicit examples."
    },
    {
        "anchor": "$\u03b7'$-$\u03b7_c$-mixing with improved stochastic estimators: Charmonia are flavour singlet mesons and thus in principle contributions from\ndisconnected quark line diagrams might affect their masses, either directly or\nvia mixing with other flavour singlet channels. We present a first study that\ntakes both effects into account. We employ improved stochastic all-to-all\npropagator techniques (including new methods) to calculate the diagrams that\nappear within the mixing matrix between the $\\eta'$ and the $\\eta_c$. The runs\nare initially performed on $N_f=2$ $16^3\\times 32$ configurations with the\nnon-perturbatively improved Sheikholeslami-Wilson action, both for valence and\nsea quarks.",
        "positive": "An example of optimal field cut in lattice gauge perturbation theory: We discuss the weak coupling expansion of a one plaquette SU(2) lattice gauge\ntheory. We show that the conventional perturbative series for the partition\nfunction has a zero radius of convergence and is asymptotic. The average\nplaquette is discontinuous at g^2=0. However, the fact that SU(2) is compact\nprovides a perturbative sum that converges toward the correct answer for\npositive g^2. This alternate methods amounts to introducing a specific coupling\ndependent field cut, that turns the coefficients into g-dependent quantities.\nGeneralizing to an arbitrary field cut, we obtain a regular power series with a\nfinite radius of convergence. At any order in the modified perturbative\nprocedure, and for a given coupling, it is possible to find at least one (and\nsometimes two) values of the field cut that provide the exact answer. This\noptimal field cut can be determined approximately using the strong coupling\nexpansion. This allows us to interpolate accurately between the weak and strong\ncoupling regions. We discuss the extension of the method to lattice gauge\ntheory on a D-dimensional cubic lattice."
    },
    {
        "anchor": "Resonance properties from the finite-volume energy spectrum: A new method based on the concept of probability distribution is proposed to\nanalyze the finite volume energy spectrum in lattice QCD. Using synthetic\nlattice data, we demonstrate that for the channel with quantum numbers of the\nDelta-resonance a clear resonance structure emerges in such an analysis.\nConsequently, measuring the volume-dependence of the energy levels in lattice\nQCD will allow to determine the mass and the width of the Delta with reasonable\naccuracy.",
        "positive": "Pion-pion interaction in the I=1 channel: We present preliminary results of a new approach to the study of the\npion-pion system in the I=1 channel. The Bethe-Salpeter wave function of the\ntwo-pion system is computed on the ground state and the first excited state.\nFrom these, we attempt to extract an interaction kernel (potential) which can\nthen be used to extract observables such as the phase shifts. In a first trial,\nwe use rather large pion masses $m_\\pi \\sim 1.05$ GeV and $m_\\pi \\sim 0.68$ GeV\nwhich do not allow rho decay."
    },
    {
        "anchor": "Connecting Lattice QCD with Chiral Perturbation Theory at Strong\n  Coupling: We study the difficulties associated with detecting chiral singularities\npredicted by chiral perturbation theory (ChPT) in lattice QCD. We focus on the\nphysics of the remnant O(2) chiral symmetry of staggered fermions in the strong\ncoupling limit using the recently discovered directed path algorithm. Since it\nis easier to look for power-like singularities as compared to logarithmic ones,\nour calculations are performed at a fixed finite temperature in the chirally\nbroken phase. We show that the behavior of the chiral condensate, the pion mass\nand the pion decay constant, for small masses, are all consistent with the\npredictions of ChPT.\n  However, the values of the quark masses that we need to demonstrate this are\nmuch smaller than those being used in dynamical QCD simulations. We also need\nto use higher order terms in the chiral expansion to fit our data.",
        "positive": "The eigenvalue spectrum for dynamical Chirally Improved fermions: We study the eigenvalues of Dirac operators in QCD with two mass degenerate\ndynamical fermions. The gauge configurations have been obtained with HMC and\nthe so-called Chirally Improved fermionic action. We compare eigenvalues\nobtained for the overlap Dirac operator on these configurations with those for\nthe Chirally Improved (CI) operator (studied earlier). Results of Random Matrix\nTheory allow us to determine the chiral condensate."
    },
    {
        "anchor": "The Chiral Condensate in a Finite Volume: Chiral perturbation theory at finite four-volume V (=L^3T) is reconsidered\nwith a view towards finding a computational scheme that can deal with any value\nof M_\\pi L, where M_\\pi is a generic Nambu-Goldstone mass. The momentum zero\nmodes that cause the usual p-expansion to fail in the chiral limit are treated\nseparately, and partly integrated out to all orders. In this way the theory\nremains infrared finite in the perturbative expansion, and the chiral limit can\nbe considered at finite volume. We illustrate the technique by computing the\nquark condensate in a finite volume, smoothly connecting standard results in\nthe p-regime for larger masses with those of the epsilon-regime for smaller\nmasses. From the partially quenched theory we also obtain the spectral density\nof the Dirac operator, a smooth function from the microscopic region to the\nbulk region of the p-regime.",
        "positive": "The curvature of the chiral pseudocritical line from LQCD: analytic\n  continuation and Taylor expansion compared: We present a determination of the curvature $\\kappa$ of the chiral\npseudocritical line from $N_f=2+1$ lattice QCD at the physical point obtained\nby adopting the Taylor expansion approach. Numerical simulations performed at\nthree lattice spacings lead to a continuum extrapolated curvature $\\kappa =\n0.0145(25)$, a value that is in excellent agreement with continuum limit\nestimates obtained via analytic continuation within the same discretization\nscheme, $\\kappa = 0.0135(20)$. The agreement between the two calculations is a\nsolid consistency check for both methods."
    },
    {
        "anchor": "Magnetic operators in 2D compact scalar field theories on the lattice: In lattice compact gauge theories, we must impose the admissibility condition\nto have well-defined topological sectors. The admissibility condition, however,\nusually forbids the presence of magnetic operators, and it is not so trivial if\none can study the monopole physics depending on the topological term, such as\nthe Witten effect, on the lattice. In this paper, we address this question in\nthe case of 2D compact scalars as it would be one of the simplest examples\nhaving analogues of the monopole and the topological term. To define the\nmagnetic operator, we propose the ``excision method,'' which consists of\nexcising lattice links (or bonds) in an appropriate region containing the\nmonopole and defining the dual lattice in a particular way. The size of the\nexcised region is $O(1)$ in lattice units so that the monopole becomes\npoint-like in the continuum limit. We give the lattice derivation of the\n't~Hooft anomalies between the electric and magnetic symmetries and also derive\nthe higher-group-like structure related to the Witten effect.",
        "positive": "Meson and Baryon dispersion relations with Brillouin fermions: We study the dispersion relations of mesons and baryons built from Brillouin\nquarks on one N_f=2 gauge ensemble provided by QCDSF. For quark masses up to\nthe physical strange quark mass, there is hardly any improvement over the\nWilson discretization, if either action is link-smeared and tree-level clover\nimproved. For quark masses in the range of the physical charm quark mass, the\nBrillouin action still shows a perfect relativistic behavior, while the Wilson\naction induces severe cut-off effects. As an application we determine the\nmasses of the \\Omega_c^0, \\Omega_{cc}^+ and \\Omega_{ccc}^{++} baryons on that\nensemble."
    },
    {
        "anchor": "Orthogonal Technicolor with Isotriplet Dark Matter on the Lattice: We study the gauge dynamics of an SO(4)-gauge theory with two Dirac Wilson\nfermions transforming according to the vector representation of the gauge\ngroup. We determine the lattice phase diagram by locating the strong coupling\nbulk phase transition line and the zero PCAC mass line. We present results for\nthe spectrum of the theory. In particular we measure the pseudoscalar, vector\nand axial meson masses. The data are consistent with a chiral symmetry breaking\nscenario rather than a conformal one. When used to break the electroweak\nsymmetry dynamically the model leads to a natural dark matter candidate.",
        "positive": "On the Neuberger overlap operator: We compute Neuberger's overlap operator by the Lanczos algorithm applied to\nthe Wilson-Dirac operator. Locality of the operator for quenched QCD data and\nits eigenvalue spectrum in an instanton background are studied."
    },
    {
        "anchor": "Glueball spectroscopy in lattice QCD using gradient flow: Removing ultraviolet noise from the gauge fields is necessary for glueball\nspectroscopy in lattice QCD. It is known that the Yang-Mills gradient flow\nmethod is an alternative approach instead of link smearing or link fuzzing in\nvarious aspects. In this work we study the application of the gradient flow\ntechnique to the construction of the extended glueball operators. We examine a\nsimple application of the gradient flow method, which has some problems in\nglueball mass calculations at large flow time because of its nature of\ndiffusion in space-time. To avoid this problem, the spatial links are evolved\nby the ``spatial gradient flow'', that is defined to restrict the diffusion to\nspatial directions only. We test the spatial gradient flow in calculations of\nglueball two-point functions and Wilson loops as a new smearing method, and\nthen discuss its efficiency in comparison with the original gradient flow\nmethod and the conventional method. Furthermore, to demonstrate the feasibility\nof our proposed method, we determine the masses of the three lowest-lying\nglueball states, corresponding to the $0^{++}$, $2^{++}$ and $0^{-+}$\nglueballs, in the continuum limit in the pure Yang-Mills theory.",
        "positive": "SESAM and TXL Results for Wilson Action--A Status Report: Results from two studies of full QCD with two flavours of dynamical Wilson\nfermions are presented. At beta=5.6, the region 0.83 > m_pi/m_rho > 0.56 at\nm_pia > 0.23 L^{-1} is explored. The SESAM collaboration has generated\nensembles of about 200 statistically independent configurations on a 16^3 x\n32-lattice at three different kappa-values and is entering the final phase of\ndata analysis. The TXL simulation on a 24^3 x 40-lattice at two kappa-values\nhas reached half statistics and data analysis has started recently, hence most\nresults presented here are preliminary. The focus of this report is fourfold:\nwe demonstrate that algorithmic improvements like fast Krylov solvers and\nparallel preconditioning recently introduced can be put into practise in full\nQCD simulations, we present encouraging observations as to the critical\ndynamics of the Hybrid Monte Carlo algorithm in the approach to the chiral\nlimit, we mention signal improvements of noisy estimator techniques for\ndisconnected diagrams to the pi-N sigma term, and we report on SESAM's results\nfor light hadron spectrum, light quark masses, and heavy quarkonia."
    },
    {
        "anchor": "Baryon properties in meson mediums from lattice QCD: We present results for the ground-state mass shifts of octet baryons due to\nthe presence of a medium of pions or kaons from a lattice QCD calculation\nperformed at a single value of the quark mass, corresponding to a pion mass of\n$m_\\pi$ ~ 390 MeV, and a spatial volume V ~ (4fm)^3. We use a canonical\napproach in which correlators are formed using a single baryon propagator and a\nfixed number of meson propagators, up to n=9. From the ground-state energies we\ncalculate two- and three-body interaction parameters. We also extract\ncombinations of low-energy constants by comparing our results to tree level\nchiral perturbation theory at non-zero isospin/kaon chemical potential.",
        "positive": "Dynamical Fermion on Random-Block Lattice: Massless fermion field interacting with abelian dynamical gauge field on\n2-dimensional random-block lattices are investigated using Hybrid Monte Carlo\nsimulations. Preliminary results of the Wilson loop and the chiral correlation\nfunction are in agreement with the continuum Schwinger model."
    },
    {
        "anchor": "Parallel software for lattice N=4 supersymmetric Yang--Mills theory: We present new parallel software, SUSY LATTICE, for lattice studies of\nfour-dimensional $\\mathcal N = 4$ supersymmetric Yang--Mills theory with gauge\ngroup SU(N). The lattice action is constructed to exactly preserve a single\nsupersymmetry charge at non-zero lattice spacing, up to additional potential\nterms included to stabilize numerical simulations. The software evolved from\nthe MILC code for lattice QCD, and retains a similar large-scale framework\ndespite the different target theory. Many routines are adapted from an existing\nserial code, which SUSY LATTICE supersedes. This paper provides an overview of\nthe new parallel software, summarizing the lattice system, describing the\napplications that are currently provided and explaining their basic workflow\nfor non-experts in lattice gauge theory. We discuss the parallel performance of\nthe code, and highlight some notable aspects of the documentation for those\ninterested in contributing to its future development.",
        "positive": "Semileptonic B to D decays at nonzero recoil with 2+1 flavors of\n  improved staggered quarks: The Fermilab Lattice-MILC collaboration is completing a comprehensive program\nof heavy-light physics on the MILC (2+1)-flavor asqtad ensembles with lattice\nspacings as small as 0.045 fm and light-to-strange-quark mass ratios as low as\n1/20. We use the Fermilab interpretation of the clover action for heavy valence\nquarks and the asqtad action for light valence quarks. The central goal of the\nprogram is to provide ever more exacting tests of the unitarity of the CKM\nmatrix. We give a progress report on one part of the program, namely the\nanalysis of the semileptonic decay B to D at both zero and nonzero recoil.\nAlthough final results are not presented, we discuss improvements in the\nanalysis methods, the statistical errors, and the parameter coverage that we\nexpect will lead to a significant reduction in the final error for |V_cb| from\nthis decay channel."
    },
    {
        "anchor": "Complex spectrum of spin models for finite-density QCD: We consider the spectrum of transfer matrix eigenvalues associated with\nPolyakov loops in lattice QCD at strong coupling. The transfer matrix at finite\ndensity is non-Hermitian, and its eigenvalues become complex as a manifestation\nof the sign problem. We show that the symmetry under charge conjugation and\ncomplex conjugation ensures that the eigenvalues are either real or part of a\ncomplex conjugate pair, and the complex pairs lead to damped oscillatory\nbehavior in Polyakov loop correlation functions, which also appeared in our\nprevious phenomenological models using complex saddle points. We argue that\nthis effect should be observable in lattice simulations of QCD at finite\ndensity.",
        "positive": "The residual mass in Lattice Heavy Quark Effective Theory to alpha^3\n  order: We determine to order alpha^3 in the quenched approximation the so-called\nresidual mass in the lattice regularisation of the Heavy Quark Effective\nTheory. We follow a gauge-invariant strategy which exploits the fact that this\nmass term dominates the exponential decrease of perturbative Wilson loops at\nlarge perimeters. Our computational tool is Numerical Stochastic Perturbation\nTheory. The new coefficient we compute is crucial to improve the determination\nof the (MS bar) mass of the b-quark from lattice simulations of the Heavy Quark\nEffective Theory."
    },
    {
        "anchor": "A Phenomenological Treatment of Chiral Symmetry Restoration and\n  Deconfinement: A phenomenological expression for the thermodynamic potential of gluons and\nquarks is constructed which incorporates the features of deconfinement and\nchiral symmetry restoration known from lattice simulations. The thermodynamic\npotential is a function of the Polyakov loop and chiral condensate expectation\nvalues. The gluonic sector uses a successful model for pure (SU(N_c)) gauge\ntheories in which the Polyakov loop eigenvalues are the fundamental order\nparameters for deconfinement. The quark sector is given by a Nambu-Jona-Lasinio\nmodel in which a constant background (A_0) field couples the chiral condensate\nto the Polyakov loop. We consider the case of (N_f = 2) in detail. For two\nmassless quarks, we find a second order chiral phase transition. Confinement\neffects push the transition to higher temperatures, but the entropy associated\nwith the gluonic sector acts in the opposite direction. For light mass quarks,\nonly a rapid crossover occurs. For sufficiently heavy quarks, a first order\ndeconfinement transition emerges. This simplest model has one adjustable\nparameter, which can be set from the chiral transition temperature for light\nquarks. It predicts all thermodynamic quantities as well as the behavior of the\nchiral condensate and the Polyakov loop over a wide range of temperatures.",
        "positive": "Scattering phase shift determinations from a two-scalar field theory: A field theory involving two interacting scalar fields, previously studied by\nRummukainen and Gottlieb, is revisited. Our study is not restricted to the\nlimit of large quartic couplings, and a Symanzik-improved action is used so\nthat continuum dispersion relations work well. The Metropolis method, combined\nwith a local microcanonical updating algorithm, is employed in our Monte Carlo\ncalculations. Isotropic lattices ranging from $16^3 \\times 48$ to $53^3 \\times\n48$ are used, and scattering phase shifts are determined using a L\\\"uscher\nanalysis with multiple partial waves."
    },
    {
        "anchor": "Conserving Lattice Gauge Theory for Finite Systems: In this study I develop a novel action for lattice gauge theory for finite\nsystems, which accommodates non-periodic boundary conditions, implements the\nproper integral form of Gauss' law and exhibits an inherently symmetric energy\nmomentum tensor, all while realizing automatic ${\\cal O}(a)$ improvement.\nTaking the modern summation-by-parts formulation for finite differences as\nstarting point and combining it with insight from the finite volume strategies\nof computational electrodynamics I show how the concept of a conserving\ndiscretization can be realized for non-Abelian lattice gauge theory. Major\nsteps in the derivation are illustrated using Abelian gauge theory as example.",
        "positive": "Position-Space Renormalisation of the Energy-Momentum Tensor: There is increasing interest in the study of nonperturbative aspects of\nthree-dimensional quantum field theories (QFT). They appear as holographic dual\nto theories of (strongly coupled) gravity. For instance, in Holographic\nCosmology, the two-point function of the Energy-Momentum Tensor (EMT) of a\nparticular class of three-dimensional QFTs can be mapped into the power\nspectrum of the Cosmic Microwave Background in the gravitational theory.\nHowever, the presence of divergent contact terms poses challenges in extracting\na renormalised EMT two-point function on the lattice. Using a $\\phi^4$ theory\nof adjoint scalars valued in the $\\mathfrak{su}(N)$ Lie Algebra as a\nproof-of-concept motivated by Holographic Cosmology, we apply a novel method\nfor filtering out such contact terms by making use of infinitely differentiable\n\"bump\" functions which enforce a smooth window that excludes contributions at\nzero spatial separation. The process effectively removes the local contact\nterms and allows us to extract the continuum limit behaviour of the\nrenormalised EMT two-point function."
    },
    {
        "anchor": "Lattice QCD Green's functions in maximally Abelian gauge: infrared\n  Abelian dominance and the quark sector: On lattice gauge field configurations with 2+1 dynamical quark flavors, we\ninvestigate the momentum space quark and gluon propagators in the combined\nmaximally Abelian plus $U(1)_3\\times U(1)_8$ Landau gauge. We extract the gluon\nfields from the lattice link variables and study the diagonal and off-diagonal\ngluon propagators. We find that the infrared region of the transverse diagonal\ngluon propagator is strongly enhanced compared to the off-diagonal propagator.\nThe Dirac operator from the Asqtad action is inverted on the diagonal and\noff-diagonal gluon backgrounds separately. In agreement with the hypothesis of\ninfrared Abelian dominance, we find that the off-diagonal gluon background\nhardly gives rise to any non-trivial quark dynamics while the quark propagator\nfrom the diagonal gluon background closely resembles its Landau gauge\ncounterpart.",
        "positive": "The running coupling of 8 flavors and 3 colors: We compute the renormalized running coupling of SU(3) gauge theory coupled to\nN_f = 8 flavors of massless fundamental Dirac fermions. The recently proposed\nfinite volume gradient flow scheme is used. The calculations are performed at\nseveral lattice spacings allowing for a controlled continuum extrapolation. The\nresults for the discrete beta-function show that it is monotonic without any\nsign of a fixed point in the range of couplings we cover. As a cross check the\ncontinuum results are compared with the well-known perturbative continuum\nbeta-function for small values of the renormalized coupling and perfect\nagreement is found."
    },
    {
        "anchor": "A New Lattice Action for Studying Topological Charge: We review our recent proposal for a new lattice action for non-abelian gauge\ntheories which reduces short-range lattice artifacts in the computation of the\ntopological susceptibility. The standard Wilson action is replaced by the\nWilson action of a gauge covariant interpolation of the original fields to a\nfiner lattice. We illustrate the improved behavior of a same-philosophy new\nlattice action in the $O(3)$ $\\sigma$-model in two dimensions.",
        "positive": "Recent Progress on the QCD Phase Diagram: Recent progress and the latest results on the bulk thermodynamic properties\nof QCD matter from lattice are reviewed. In particular, I will stress upon the\nfact that lattice techniques are now entering into precision era where they can\nprovide us with new insights on even the microscopic degrees of freedom in\ndifferent phases of QCD. I will discuss some instances, from the recent studies\nof topological fluctuations and screening masses. The progress towards\nunderstanding the effects of anomalous $U_A(1)$ symmetry on the chiral\ncrossover transition and transport properties of QCD matter will also be\ndiscussed."
    },
    {
        "anchor": "Highly Improved Naive and Staggered Fermions: We present a new action for highly improved staggered fermions. We show that\nperturbative calculations for the new action are well-behaved where those of\nthe conventional staggered action are badly behaved. We discuss the effects of\nthe new terms in controlling flavor mixing, and discuss the design of operators\nfor the action.",
        "positive": "Thimble regularization at work besides toy models: from Random Matrix\n  Theory to Gauge Theories: Thimble regularization as a solution to the sign problem has been\nsuccessfully put at work for a few toy models. Given the non trivial nature of\nthe method (also from the algorithmic point of view) it is compelling to\nprovide evidence that it works for realistic models. A Chiral Random Matrix\ntheory has been studied in detail. The known analytical solution shows that the\nmodel is non-trivial as for the sign problem (in particular, phase quenched\nresults can be very far away from the exact solution). This study gave us the\nchance to address a couple of key issues: how many thimbles contribute to the\nsolution of a realistic problem? Can one devise algorithms which are robust as\nfor staying on the correct manifold? The obvious step forward consists of\napplications to gauge theories."
    },
    {
        "anchor": "Phase transition and dynamical-parameter method in U(1) gauge theory: Monte Carlo simulations of the 4-dimensional compact U(1) lattice gauge\ntheory in the neighborhood of the transition point are made difficult by the\nsuppression of tunneling between the phases, which becomes very strong as soon\nas the volume of the lattice grows to any appreciable size. This problem can be\navoided by making the monopole coupling a dynamical variable. In this manner\none can circumvent the tunneling barrier by effectively riding on top of the\npeaks in the energy distribution which meet for sufficiently large monopole\ncoupling. Here we present an efficient method for determining the parameters\nneeded for this procedure, which can thus be implemented at low computational\ncost also on large lattices. This is particularly important for a reliable\ndetermination of the transition point. We demonstrate the working of our method\non a 16^4 lattice. We obtain an equidistribution of configurations across the\nphase transition even for such a relatively large lattice size.",
        "positive": "Exact chiral symmetry on the lattice and the Ginsparg-Wilson relation: It is shown that the Ginsparg-Wilson relation implies an exact symmetry of\nthe fermion action, which may be regarded as a lattice form of an infinitesimal\nchiral rotation. Using this result it is straightforward to construct lattice\nYukawa models with unbroken flavour and chiral symmetries and no doubling of\nthe fermion spectrum. A contradiction with the Nielsen-Ninomiya theorem is\navoided, because the chiral symmetry is realized in a different way than has\nbeen assumed when proving the theorem."
    },
    {
        "anchor": "Large-$N_c$ gauge theory and chiral random matrix theory: We discuss how the $1/N_c$ expansion and the chiral random matrix theory\n($\\chi$RMT) can be used in the study of large-$N_c$ gauge theories. We first\nclarify the parameter region in which each of these two approaches is valid:\nwhile the fermion mass $m$ is fixed in the standard large-$N_c$ arguments ('t\nHooft large-$N_c$ limit), $m$ must be scaled appropriately with a certain\nnegative power of $N_c$ in order for the gauge theories to be described by the\n$\\chi$RMT. Then, although these two limits are not compatible in general, we\nshow that the breakdown of chiral symmetry can be detected by combining the\nlarge-$N_c$ argument and the $\\chi$RMT with some cares. As a concrete example,\nwe numerically study the four dimensional $SU(N_c)$ gauge theory with $N_f=2$\nheavy adjoint fermions, introduced as the center symmetry preserver keeping the\ninfrared physics intact, on a $2^4$ lattice. By looking at the low-lying\neigenvalues of the Dirac operator for a massless probe fermion in the adjoint\nrepresentation, we find that the chiral symmetry is indeed broken with the\nexpected breaking pattern. This result reproduces a well-known fact that the\nchiral symmetry is spontaneously broken in the pure $SU(N_c)$ gauge theory in\nthe large-$N_c$ and the large-volume limit, and therefore supports the validity\nof the combined approach. We also provide the interpretation of the gap and\nunexpected $N_c$-scaling, both of which are observed in the Dirac spectrum.",
        "positive": "The Nambu-Jona-Lasinio model with staggered fermions: We investigate the neighbourhood of the chiral phase transition in a lattice\nNambu--Jona-Lasinio model, using both Monte Carlo methods and lattice\nSchwinger-Dyson equations."
    },
    {
        "anchor": "Comment on \"'t Hooft vertices, partial quenching, and rooted staggered\n  QCD\": A recent criticism of the proof of the failure of the rooting procedure with\nstaggered fermions is shown to be incorrect.",
        "positive": "A lattice formulation of the Atiyah-Patodi-Singer index: Atiyah-Singer index theorem on a lattice without boundary is well understood\nowing to the seminal work by Hasenfratz et al. But its extension to the system\nwith boundary (the so-called Atiyah- Patodi-Singer index theorem), which plays\na crucial role in T-anomaly cancellation between bulk- and edge-modes in 3+1\ndimensional topological matters, is known only in the continuum theory and no\nlattice realization has been made so far. In this work, we try to\nnon-perturbatively define an alternative index from the lattice domain-wall\nfermion in 3+1 dimensions. We will show that this new index in the continuum\nlimit, converges to the Atiyah-Patodi-Singer index defined on a manifold with\nboundary, which coincides with the surface of the domain-wall."
    },
    {
        "anchor": "High-accuracy two-loop computation of the critical mass for Wilson\n  fermions: We test an algebraic algorithm based on the coordinate-space method,\nevaluating with high accuracy the critical mass for Wilson fermions in lattice\nQCD at two loops. We test the results by using different types of infrared\nregularization.",
        "positive": "Double Hairpin Diagrams and the Planar Equivalence of N=1 Supersymmetric\n  Yang-Mills Theory and One-Flavor QCD: Recent work by Armoni, Shifman, and Veneziano suggests a large-N equivalence\nbetween supersymmetric Yang-Mills Theory and one-flavor QCD. One consequence of\nthis \"orientifold projection\" is that scalar and pseudoscalar mesons in\none-flavor QCD should have degenerate mass since they lie within the same\nWess-Zumino supermultiplet. We use lattice calculations to investigate the mass\nshifts caused by \"double-hairpin\" annihilation diagrams in quenched QCD to test\nfor this degeneracy. Similar quark-antiquark annihilation processes are studied\nin the 2-dimensional CP(N-1) model with quenched fermions."
    },
    {
        "anchor": "Finite-volume effects due to spatially non-local operators: Spatially non-local matrix elements are useful lattice-QCD observables in a\nvariety of contexts, for example in determining hadron structure. To quote\ncredible estimates of the systematic uncertainties in these calculations, one\nmust understand, among other things, the size of the finite-volume effects when\nsuch matrix elements are extracted from numerical lattice calculations. In this\nwork, we estimate finite-volume effects for matrix elements of non-local\noperators, composed of two currents displaced in a spatial direction by a\ndistance $\\xi$. We find that the finite-volume corrections depend on the\ndetails of the matrix element. If the external state is the lightest degree of\nfreedom in the theory, e.g.~the pion in QCD, then the volume corrections scale\nas $ e^{-m_\\pi (L- \\xi)} $, where $m_\\pi$ is the mass of the light state. For\nheavier external states the usual $e^{- m_\\pi L}$ form is recovered, but with a\npolynomial prefactor of the form $L^m/|L - \\xi|^n$ that can lead to enhanced\nvolume effects. These observations are potentially relevant to a wide variety\nof observables being studied using lattice QCD, including parton distribution\nfunctions, double-beta-decay and Compton-scattering matrix elements, and\nlong-range weak matrix elements.",
        "positive": "On cutoff effects in lattice QCD from short to long distances: We discuss kinematical enhancements of cutoff effects at short and\nintermediate distances. Starting from a pedagogical example with periodic\nboundary conditions, we switch to the case of the Schroedinger Functional,\nwhere the theoretical analysis is checked by precise numerical data with Nf=2\ndynamical O(a)-improved Wilson quarks. Finally we present an improved\ndetermination of the renormalization of the axial current in that theory."
    },
    {
        "anchor": "Nucleon structure with two flavors of dynamical domain-wall fermions: We present a numerical lattice quantum chromodynamics calculation of\nisovector form factors and the first few moments of the isovector structure\nfunctions of the nucleon. The calculation employs two degenerate dynamical\nflavors of domain-wall fermions, resulting in good control of chiral symmetry\nbreaking. Non-perturbative renormalization of the relevant quark currents is\nperformed where necessary. The inverse lattice spacing, $a^{-1}$, is about 1.7\nGeV. We use degenerate up and down dynamical quark masses around 1, 3/4 and 1/2\nthe strange quark mass. The physical volume of the lattice is about\n$(1.9{fm})^3$. The ratio of the isovector vector to axial charges, $g_A/g_V$,\ntrends a bit lower than the experimental value as the quark mass is reduced\ntoward the physical point. We calculate the momentum-transfer dependences of\nthe isovector vector, axial, induced tensor and induced pseudoscalar form\nfactors. The Goldberger-Treiman relation holds at low momentum transfer and\nyields a pion-nucleon coupling, $g_{\\pi NN} = 15.5(1.4)$, where the quoted\nerror is only statistical. We find that the flavor non-singlet quark momentum\nfraction $<x>_{u-d}$ and quark helicity fraction $<x>_{\\Delta u-\\Delta d}$\novershoot their experimental values after linear chiral extrapolation. We\nobtain the transversity, $<1 >_{\\delta u-\\delta d} = 0.93(6)$ in $\\bar{\\rm MS}$\nat 2 GeV and a twist-3 polarized moment, $d_1$, appears small, suggesting that\nthe Wandzura-Wilczek relation holds approximately. We discuss the systematic\nerrors in the calculation, with particular attention paid to finite-volume\neffects, excited-state contamination, and chiral extrapolations.",
        "positive": "Light Hadron Masses and Decay Constants: The extraction of the light hadron spectrum from a first-principle Quantum\nChromodynamics approach is a profound application for lattice simulations of\nQuantum Chromodynamics.\n  This review will cover recent lattice results for the masses and decay\nconstants of the light hadrons. In particular, the applicability of different\napproaches for the extrapolation towards the physical point will be discussed."
    },
    {
        "anchor": "A lattice study of $\u039b_b$ semileptonic decay: We present results from a lattice study of the semileptonic decay $\\Lambda_b\n\\to \\Lambda_c l \\nu_l $. We use $O(a^2, \\alpha_s a^2)$ improved quenched\nlattices of the MILC collaboration, with lattice spacing $\\sim 0.13$ fm. For\nthe valence quarks, the tadpole-improved clover action is used, with the\nFermilab method employed for the heavy quarks. Form factors are extracted from\nthe vector as well as the axial-vector part of the current.",
        "positive": "An update in monopole condensation in two-flavour Adjoint QCD: QCD with fermions in the adjoint representation (aQCD) is a model for which a\ndeconfinement and a chiral phase transition take place at different\ntemperatures. In this work, we present a study of the deconfinement transition\nin the dual superconductor picture based on the evaluation of an operator which\ncarries magnetic charge. The expectation value of this operator signals\nmonopole condensation and is an order parameter for deconfinement as in the\ncase of fermions in the fundamental representation. We find a sharp first order\ndeconfinement transition. We also study the effects of the chiral transition on\nthe monopole order parameter and find them negligible."
    },
    {
        "anchor": "Towards non-perturbative matching of three/four-flavor Wilson\n  coefficients with a position-space procedure: We propose a strategy to non-perturbatively match the Wilson coefficients in\nthe three- and four-flavor theories, which uses two-point Green's functions of\nthe corresponding four-quark operators at long distances. The idea is refined\nby combining with the spherical averaging technique, which enables us to\nconvert two-point functions calculated on the lattice into continuous functions\nof the distance $|x-y|$ between two operators. We also show the result for an\nexploratory calculation of two-point functions of the $\\Delta S=1$ operators\n$Q_7$ and $Q_8$ that are in the $(8_L,8_R)$ representation of ${\\rm\nSU(3)}_L\\times{\\rm SU(3)}_R$ and mix with each other.",
        "positive": "Parton Distribution Function with Non-perturbative Renormalization from\n  Lattice QCD: We present lattice results for the isovector unpolarized parton distribution\nwith nonperturbative RI/MOM-scheme renormalization on the lattice. In the\nframework of large-momentum effective field theory (LaMET), the full\nBjorken-$x$ dependence of a momentum-dependent quasi-distribution is calculated\non the lattice and matched to the ordinary lightcone parton distribution at\none-loop order, with power corrections included. The important step of RI/MOM\nrenormalization that connects the lattice and continuum matrix elements is\ndetailed in this paper. A few consequences of the results are also addressed\nhere."
    },
    {
        "anchor": "Overlap-Dirac fermions with a small hopping parameter: We consider overlap-Dirac fermions at non-zero bare coupling and for a small\nhopping parameter, or, equivalently, large $|M|$ with $M$ the domain-wall\nheight. We prove the existence of a phase at large positive $M$ where the\nabelian axial group $U_A(1)$ is a symmetry, and the corresponding pseudo-scalar\nis an exact Goldstone boson. We also provide a conjecture for the phase diagram\nof asymptotically free gauge theories with overlap-Dirac fermions. In\nparticular, we suggest that, for large gauge coupling, the massive-fermion\nphase at negative $M$ possibly extends to all $M<4$.",
        "positive": "Generalized ensemble algorithm for U(1) gauge theory: Hybrid Monte Carlo simulations of the pure compact U(1) gauge theory are\nperformed with the Tsallis weight. The simulations show that the use of the\nTsallis weight enhances the tunneling rate between metastable states."
    },
    {
        "anchor": "Sunset integrals at finite volume: Chiral Perturbation Theory is a useful tool to aid in performing the various\nextrapolations needed in lattice QCD calculations of physical quantities. These\ninclude extrapolations in quark mass, finite lattice spacing and finite size of\nthe lattice. Especially the latter will become more important when the quark\nmasses on the lattice become smaller.\n  Here we develop the needed two-loop integrals at finite volume to do the\ncalculations for masses and decay constants for all general mass cases.\n  I will present results based on an expansion in Bessel functions as well as\non a version using theta functions and compare their efficiency. Work is in\nprogress to combine these results with two-loop ChPT calculations.",
        "positive": "The Magnetic Structure of Light Nuclei from Lattice QCD: Lattice QCD with background magnetic fields is used to calculate the magnetic\nmoments and magnetic polarizabilities of the nucleons and of light nuclei with\n$A\\le4$, along with the cross-section for the $M1$ transition $np\\rightarrow\nd\\gamma$, at the flavor SU(3)-symmetric point where the pion mass is $m_\\pi\\sim\n806$ MeV. These magnetic properties are extracted from nucleon and nuclear\nenergies in six uniform magnetic fields of varying strengths. The magnetic\nmoments are presented in a recent Letter. For the charged states, the\nextraction of the polarizability requires careful treatment of Landau levels,\nwhich enter non-trivially in the method that is employed. The nucleon\npolarizabilities are found to be of similar magnitude to their physical values,\nwith $\\beta_p=5.22(+0.66/-0.45)(0.23) \\times 10^{-4}$ fm$^3$ and\n$\\beta_n=1.253(+0.056/-0.067)(0.055) \\times 10^{-4}$ fm$^3$, exhibiting a\nsignificant isovector component. The dineutron is bound at these heavy quark\nmasses and its magnetic polarizability, $\\beta_{nn}=1.872(+0.121/-0.113)(0.082)\n\\times 10^{-4}$ fm$^3$ differs significantly from twice that of the neutron. A\nlinear combination of deuteron scalar and tensor polarizabilities is determined\nby the energies of the $j_z=\\pm 1$ deuteron states, and is found to be\n$\\beta_{d,\\pm 1}=4.4(+1.6/-1.5)(0.2) \\times 10^{-4}$ fm$^3$. The magnetic\npolarizabilities of the three-nucleon and four-nucleon systems are found to be\npositive and similar in size to those of the proton, $\\beta_{^{3}\\rm\nHe}=5.4(+2.2/-2.1)(0.2) \\times 10^{-4}$ fm$^3$, $\\beta_{^{3}\\rm\nH}=2.6(1.7)(0.1) \\times 10^{-4}$ fm$^3$, $\\beta_{^{4}\\rm\nHe}=3.4(+2.0/-1.9)(0.2) \\times 10^{-4}$ fm$^3$. Mixing between the $j_z=0$\ndeuteron state and the spin-singlet $np$ state induced by the background\nmagnetic field is used to extract the short-distance two-nucleon counterterm,\n${\\bar L}_1$, of the pionless effective theory for $NN$ systems (equivalent to\nthe meson-exchange current contribution in nuclear potential models), that\ndictates the cross-section for the $np\\to d\\gamma$ process near threshold.\nCombined with previous determinations of NN scattering parameters, this enables\nan ab initio determination of the threshold cross-section at these unphysical\nmasses."
    },
    {
        "anchor": "Binding Energies in Nonrelativistic Field Theories: Relativistic corrections communicate the binding energy of a bound state to\nits kinetic mass. This mechanism is reviewed and used to explain anomalous\nresults of Collins, Edwards, Heller, and Sloan (hep-lat/9512026), which\ncompared rest and kinetic masses of heavy-light mesons and quarkonia.",
        "positive": "Higher order quantization conditions for two spinless particles: Lattice QCD calculations of scattering phaseshifts and resonance parameters\nin the two-body sector are becoming precision studies. Early calculations\nemployed L\\\"uscher's formula for extracting these quantities at lowest order.\nAs the calculations become more ambitious, higher-order relations are required.\nIn this study we derive higher-order quantization conditions and introduce a\nmethod to transparently cross-check our results. This is an important step\ngiven the involved derivations of these formulae. We derive quantization\nconditions up to $\\ell=5$ partial waves in both cubic and elongated geometries,\nand for states with zero and non-zero total momentum. All 45 quantization\nconditions we include here (22 in cubic box, 23 in elongated box) pass our\ncross-check test."
    },
    {
        "anchor": "Multipoint reweighting method and its applications to lattice QCD: The reweighting method is widely used in numerical studies of QCD, in\nparticular, for the cases in which the conventional Monte-Carlo method cannot\nbe applied directly, e.g., finite density QCD. However, the application range\nof the reweighing method is restricted due to several problems. One of the most\nsevere problems here is the overlap problem. To solve it, we examine a\nmultipoint reweighting method in which simulations at several simulation points\nare combined in the data analyses. We systematically study the applicability\nand limitation of the multipoint reweighting method in two-flavor QCD at zero\ndensity. Measuring histograms of physical quantities at a series of simulation\npoints, we apply the multipoint reweighting method to calculate the meson\nmasses as continuous functions of the gauge coupling $\\beta$ and the hopping\nparameters $\\kappa$. We then determine lines of constant physics and beta\nfunctions, which are needed in a calculation of the equation of state at finite\ntemperature.",
        "positive": "Improved Pseudofermion Approach for All-Point Propagators: Quark propagators with arbitrary sources and sinks can be obtained more\nefficiently using a pseudofermion method with a mode-shifted action.\nMode-shifting solves the problem of critical slowing down (for light quarks)\ninduced by low eigenmodes of the Dirac operator. The method allows the full\nphysical content of every gauge configuration to be extracted, and should be\nespecially helpful for unquenched QCD calculations. The method can be applied\nfor all the conventional quark actions: Wilson, Sheikoleslami-Wohlert,\nKogut-Susskind, as well as Ginsparg-Wilson compliant overlap actions. The\nstatistical properties of the method are examined and examples of physical\nprocesses under study are presented."
    },
    {
        "anchor": "Dirac operator and Ising model on a compact 2D random lattice: Lattice formulation of a fermionic field theory defined on a randomly\ntriangulated compact manifold is discussed, with emphasis on the topological\nproblem of defining spin structures on the manifold. An explicit construction\nis presented for the two-dimensional case and its relation with the Ising model\nis discussed. Furthermore, an exact realization of the Kramers-Wannier duality\nfor the two-dimensional Ising model on the manifold is considered. The global\nproperties of the field are discussed. The importance of the GSO projection is\nstressed. This projection has to be performed for the duality to hold.",
        "positive": "Lattice investigation of an inhomogeneous phase of the 2+1-dimensional\n  Gross-Neveu model in the limit of infinitely many flavors: We investigate the phase structure of the 2+1-dimensional Gross-Neveu model\nin the large-Nf limit, where Nf denotes the number of fermion flavors. We\ndiscuss two different fermion representations and their implication on the\ninterpretation of a discrete symmetry of the action. We present numerical\nresults, which indicate the existence of an inhomogeneous phase similar as in\nthe 1+1-dimensional Gross-Neveu model."
    },
    {
        "anchor": "$B_c \\rightarrow J/\u03c8$ Form Factors for the full $q^2$ range from\n  Lattice QCD: We present the first lattice QCD determination of the $B_c \\rightarrow\nJ/\\psi$ vector and axial-vector form factors. These will enable experimental\ninformation on the rate for $B_c$ semileptonic decays to $J/\\psi$ to be\nconverted into a value for $V_{cb}$. Our calculation covers the full physical\n$q^2$ range of the decay and uses non-perturbatively renormalised lattice\ncurrents. We use the Highly Improved Staggered Quark (HISQ) action for all\nvalence quarks on the second generation MILC ensembles of gluon field\nconfigurations including $u$, $d$, $s$ and $c$ HISQ sea quarks. Our HISQ heavy\nquarks have masses ranging upwards from that of $c$; we are able to reach that\nof the $b$ on our finest lattices. This enables us to map out the dependence on\nheavy quark mass and determine results in the continuum limit at the $b$. We\nuse our form factors to construct the differential rates for $B_c^- \\rightarrow\nJ/\\psi \\mu^- \\bar{\\nu}_\\mu$ and obtain a total rate with $7\\%$ uncertainty:\n$\\Gamma(B_c^-\\rightarrow J/\\psi\n\\mu^-\\bar{\\nu}_{\\mu})/|\\eta_{\\mathrm{EW}}V_{cb}|^2 = 1.73(12)\\times 10^{13}\n~\\mathrm{s}^{-1}$. Including values for $V_{cb}$, $\\eta_{\\mathrm{EW}}$ and\n$\\tau_{B_c}$ yields a branching fraction for this decay mode of\n0.0150(11)(10)(3) ~with uncertainties from lattice QCD,\n$\\eta_\\mathrm{EW}V_{cb}$ and $\\tau_{B_c}$ respectively.",
        "positive": "Isospin breaking corrections to meson masses and the hadronic vacuum\n  polarization: a comparative study: We calculate the strong isospin breaking and QED corrections to meson masses\nand the hadronic vacuum polarization in an exploratory study on a\n$64\\times24^3$ lattice with an inverse lattice spacing of $a^{-1}=1.78$ GeV and\nan isospin symmetric pion mass of $m_\\pi=340$ MeV. We include QED in an\nelectro-quenched setup using two different methods, a stochastic and a\nperturbative approach. We find that the electromagnetic correction to the\nleading hadronic contribution to the anomalous magnetic moment of the muon is\nsmaller than $1\\%$ for the up quark and $0.1\\%$ for the strange quark, although\nit should be noted that this is obtained using unphysical light quark masses.\nIn addition to the results themselves, we compare the precision which can be\nreached for the same computational cost using each method. Such a comparison is\nalso made for the meson electromagnetic mass-splittings."
    },
    {
        "anchor": "Shadow Hamiltonians, Poisson Brackets, and Gauge Theories: Numerical lattice gauge theory computations to generate gauge field\nconfigurations including the effects of dynamical fermions are usually carried\nout using algorithms that require the molecular dynamics evolution of gauge\nfields using symplectic integrators. Sophisticated integrators are in common\nuse but are hard to optimise, and force-gradient integrators show promise\nespecially for large lattice volumes. We explain why symplectic integrators\nlead to very efficient Monte Carlo algorithms because they exactly conserve a\nshadow Hamiltonian. The shadow Hamiltonian may be expanded in terms of Poisson\nbrackets, and can be used to optimize the integrators. We show how this may be\ndone for gauge theories by extending the formulation of Hamiltonian mechanics\non Lie groups to include Poisson brackets and shadows, and by giving a general\nmethod for the practical computation of forces, force-gradients, and Poisson\nbrackets for gauge theories.",
        "positive": "Three fermions in a box: I calculate finite-volume effects for three identical spin-1/2 fermions in a\nbox assuming short-ranged repulsive interactions of `natural size'. This\nanalysis employs standard perturbation theory in powers of 1/L, where L^3 is\nthe volume of the box. I give results for the ground states in the A_1, T_1,\nand E cubic representations."
    },
    {
        "anchor": "Determining the scale in Lattice QCD: We discuss scale setting in the context of 2+1 dynamical fermion simulations\nwhere we approach the physical point in the quark mass plane keeping the\naverage quark mass constant. We have simulations at four beta values, and after\ndetermining the paths and lattice spacings, we give an estimation of the\nphenomenological values of various Wilson flow scales.",
        "positive": "The running coupling in lattice Landau gauge with unquenched Wilson\n  fermion and KS fermion: The running coupling of the Wilson fermon(JLQCD/CP-PACS) and that of\nKogut-Susskind(KS) fermion(MILC) are measured in the lattice Landau gauge QCD\nin $\\widetilde{MOM}$ scheme. The quark propagator of the KS fermion is also\nmeasured and we find that it is infrared suppressed. The renormalization factor\nof the running coupling and the tadpole renormalization define the scale of the\nquark wave function. Effects of the $A_\\mu^2$ condensates of a few GeV$^2$ are\nobserved in the running coupling and also in the quark propagator."
    },
    {
        "anchor": "A proposal for B-physics on current lattices: A method to extract B-physics parameters (b-quark mass and fB, fBs decay\nconstants) from currently available lattice data is presented and tested. The\napproach is based on the idea of constructing appropriate ratios of heavy-light\nmeson masses and decay constants, respectively, possessing a precisely known\nstatic limit, and evaluating them at various pairs of heavy quark masses around\nthe charm. Via a smooth interpolation in the heavy quark mass from the easily\naccessible charm region to the asymptotic point, B-physics parameters are\ncomputed with a few percent (statistical + systematic) error using recently\nproduced Nf=2 maximally twisted Wilson fermions data.",
        "positive": "Hadron-hadron interaction from SU(2) lattice QCD: We evaluate interhadron interactions in two-color lattice QCD from\nBethe-Salpeter amplitudes on the Euclidean lattice. The simulations are\nperformed in quenched SU(2) QCD with the plaquette gauge action at $\\beta =\n2.45$ and the Wilson quark action. We concentrate on S-wave scattering states\nof two scalar diquarks. Evaluating different flavor combinations with various\nquark masses, we try to find out the ingredients in hadronic interactions.\nBetween two scalar diquarks ($u C\\gamma_5 d$, the lightest baryon in SU(2)\nsystem), we observe repulsion in short-range region, even though present quark\nmasses are not very light. We define and evaluate the \"quark-exchange part\" in\nthe interaction, which is induced by adding quark-exchange diagrams, or\nequivalently, by introducing Pauli blocking among some of quarks. The repulsive\nforce in short-distance region arises only from the \"quark-exchange part\", and\ndisappears when quark-exchange diagrams are omitted. We find that the strength\nof repulsion grows in light quark-mass regime and its quark-mass dependence is\nsimilar to or slightly stronger than that of the color-magnetic interaction by\none-gluon-exchange (OGE) processes. It is qualitatively consistent with the\nconstituent-quark model picture that a color-magnetic interaction among quarks\nis the origin of repulsion. We also find a universal long-range attractive\nforce, which enters in any flavor channels of two scalar diquarks and whose\ninteraction range and strength are quark-mass independent. The weak quark-mass\ndependence of interaction ranges in each component implies that meson-exchange\ncontributions are small and subdominant, and the other contributions, {\\it ex.}\nflavor exchange processes, color-Coulomb or color-magnetic interactions, are\nconsidered to be predominant, in the quark-mass range we evaluated."
    },
    {
        "anchor": "Do Instantons of the CP(N-1) Model Melt?: In the two-dimensional CP(N-1) model one can parametrize exact many-instanton\nsolutions via N `constituents' (called `zindons'). This parameterization\nallows, in principle, a complete `melting' of individual instantons. The model\nis therefore well suited to study whether dynamics prefers a dilute or a\nstrongly overlapping ensemble of instantons. We study the statistical mechanics\nof instantons both analytically and numerically. We find that at N=2 the\ninstanton system collapses into zero-size instantons. At N=3,4 we find that\nwell-isolated instantons are dynamically preferred though 15-25% of instantons\nhave a considerable overlap with others.",
        "positive": "Polyakov loops and monopoles in QCD: Monte-Carlo simulations of abelian projection of $T \\neq 0$ pure lattice QCD\nshow that 1) Polyakov loops written in terms of abelian link fields alone play\na role of an order parameter of deconfinement transition, 2) the abelian\nPolyakov loops are decomposed into contributions from Dirac strings of\nmonopoles and from photons, 3) vanishing of the abelian Polyakov loops in the\nconfinement phase is due to the Dirac strings alone and the photons give a\nfinite contribution in both phases. Moreover, these results appear to hold good\nwith any abelian projection as seen from the studies in the maximally abelian\ngauge and in various unitary gauges."
    },
    {
        "anchor": "$\u03c1$ meson decay on asymmetrical lattices: We present a lattice QCD calculation of the characteristics of the $\\rho$\nmeson decay. The study is carried out on spatially asymmetric boxes using\nnHYP-smeared clover fermions in the quenched approximation. The resonance mass\nand coupling constant are calculate using the P-wave scattering phaseshifts, of\nthe isospin I=1 two-pion system. We use pion masses m_{\\pi}= 418 MeV and\nm_{\\pi}=312 MeV. In both cases, the $\\rho$ decay is kinematically feasible. We\nwork on lattice sizes N_z X 24^2 X 48 with lattice spacing a=0.1 fm and\nN_z=24,30,34,48.",
        "positive": "Topology in lattice QCD: The status of topology on the lattice is reviewed. Recent results show that\nthe topological susceptibility chi can be unambigously determined. Different\nmethods, if properly implemented, give results consistent with each other. For\nSU(3) the Witten-Veneziano prediction is confirmed. Preliminary results for\nfull QCD are presented. The problem there is that the usual hybrid montecarlo\nalgorithm has severe difficulty to thermalize topology. Possible ways out are\nunder study."
    },
    {
        "anchor": "Non-Abelian dual Meissner effect in SU(3) Yang-Mills theory and\n  confinement/deconfinement phase transition at finite temperature: The dual superconductivity is a promising mechanism for quark confinement. We\nhave proposed the non-Abelian dual superconductivity picture for SU(3)\nYang-Mills theory, and showed the restricted field dominance (called\nconventionally Abelian dominance), and non-Abelian magnetic monopole dominance\nin the string tension. We have further demonstrated by measuring the\nchromoelectric flux that the non-Abelian dual Meissner effect exists and\ndetermined that the dual superconductivity for SU(3) case is of type I, which\nis in sharp contrast to the SU(2) case: the border of type I and type II.\n  In this talk, we focus on the confinement/deconfinement phase transition and\nthe non-Abelian dual superconductivity at a finite temperature: We measure the\nPolyakov loop average and correlator and investigate the restricted field\ndominance in the Polyakov loop. Then, we measure the chromoelectric flux\nbetween a pair of static quark and antiquark created by a pair of Polyakov\nloops, and investigate the non-Abelian dual Meissner effect and its relevance\nto the phase transition.",
        "positive": "Wilson mass dependence of the overlap topological charge density: The dependence of the overlap Dirac operator on the Wilson-mass regulator\nparameter is studied through calculations of the overlap topological charge\ndensities at a variety of Wilson-mass values. In this formulation, the\nWilson-mass is used in the negative mass region and acts as a regulator\ngoverning the scale at which the Dirac operator is sensitive to topological\naspects of the gauge field. We observe a clear dependence on the value of the\nWilson-mass and demonstrate how these values can be calibrated against a finite\nnumber of stout-link smearing sweeps. The overlap topological charge density is\nalso computed using a pre-smeared gauge field for the input kernel. We show how\napplying the overlap operator leads to further filtering of the gauge field.\nThe results suggest that the freedom typically associated with smearing\nalgorithms, through the variable number of sweeps, also exists in the overlap\noperator, through the variable Wilson-mass parameter."
    },
    {
        "anchor": "Formal Developments for Lattice QCD with Applications to Hadronic\n  Systems: Lattice quantum chromodynamics (QCD) will soon become the primary theoretical\ntool in rigorous studies of single- and multi-hadron sectors of QCD. It is\ntruly ab initio meaning that its only parameters are those of standard model.\nThe result of a lattice QCD calculation corresponds to that of nature only in\nthe limit when the volume of spacetime is taken to infinity and the spacing\nbetween discretized points on the lattice is taken to zero. A better\nunderstanding of these discretization and volume effects not only provides the\nconnection to the infinite-volume continuum observables, but also leads to\noptimized calculations that can be performed with available computational\nresources. This thesis includes various formal developments in this direction,\nalong with proposals for improvements, to be applied to the upcoming lattice\nQCD studies of nuclear and hadronic systems. Among these developments are i) an\nanalytical investigation of the recovery of rotational symmetry with the use of\nsuitably-formed smeared operators toward the continuum limit, ii) an extension\nof the Luscher finite-volume method to two-nucleon systems with arbitrary\nangular momentum, spin, parity and center of mass momentum, iii) the\napplication of such formalism in extracting the scattering parameters of the\n3S1-3D1 coupled channels, iv) an investigation of twisted boundary conditions\nin the single- and two-hadron sectors, with proposals for improving the\nvolume-dependence of the deuteron binding energy upon proper choices of\nboundary conditions, and v) exploring the volume dependence of the masses of\nhadrons and light-nuclei due to quantum electrodynamic interactions, including\nthe effects arising from particles' compositeness. The required background as\nwell as a brief status report of the field pertinent to the discussions in this\nthesis are presented.",
        "positive": "Status and challenges of simulations with dynamical fermions: An overview over the current state of algorithms for dynamical fermion\nsimulations is given. In particular some insight into the functioning of the\ndeterminant spitting techniques is discussed. The critical slowing down of the\nsimulations towards the continuum limit and the role of the boundary conditions\nis also reviewed."
    },
    {
        "anchor": "QCD propagators and vertices from lattice QCD (in memory of Michael\n  M\u00fcller-Preu\u00dfker): We review lattice calculations of the elementary Greens functions of QCD with\na special emphasis on the Landau gauge. These lattice results have been of\ninterest to continuum approaches to QCD over the past 20 years. They are used\nas reference for Dyson-Schwinger- and functional renormalization group equation\ncalculations as well as for hadronic bound-state equations. The lattice\nprovides low-energy data for propagators and three-point vertices in Landau\ngauge at zero and finite temperature even including dynamical fermions. We\nsummarize Michael M\\\"uller-Preu{\\ss}ker's important contributions to this field\nand put them into the perspective of his other research interests.",
        "positive": "The chiral condensate from the Dirac spectrum in BSM gauge theories: The eigenvalues of the Dirac operator at finite volume encode whether or not\nchiral symmetry is spontaneously broken in a massless theory. We apply this\nframework in a particular BSM context, namely SU(3) gauge theory with N_f=2\nmassless flavors in the 2-index symmetric (sextet) representation. Our first\nresults are at a single lattice spacing. We find that both the density of\nnear-zero eigenvalues and the renormalization group invariant mode number\nindicate spontaneous symmetry breaking. Quantitatively, there is a discrepancy\nbetween the determination of the fermion condensate in the chiral limit via the\neigenvalue spectrum and the determinations from direct measurements of the\nchiral condensate and the GMOR relation. We comment on possible explanations of\nthis discrepancy and further refinements of this study."
    },
    {
        "anchor": "Symmetry Properties of Nonlocal Quark Bilinear Operators on a Lattice: Using symmetry properties, we determine the mixing pattern of a class of\nnonlocal quark bilinear operators containing a straight Wilson line along a\nspatial direction. We confirm the previous study that mixing among the lowest\ndimensional operators, which have mass dimension equals three, can occur if\nchiral symmetry is broken in the lattice action. For higher dimensional\noperators, we find that the dimension three operators will always mix with\ndimension four operators even if chiral symmetry is preserved. Also, the number\nof dimension four operators involved in the mixing is large hence it is\nimpractical to remove the mixing by the improvement procedure. Our result is\nimportant to determining the Bjorken-$x$ dependence parton distribution\nfunctions using the quasi-distribution method on a Euclidean lattice. The\nrequirement of using large hadron momentum in this approach makes the control\nof errors from dimension four operators even more important.",
        "positive": "Nucleon-Nucleon Scattering Parameters in the Limit of SU(3) Flavor\n  Symmetry: The scattering lengths and effective ranges that describe low-energy\nnucleon-nucleon scattering are calculated in the limit of SU(3)-flavor symmetry\nat the physical strange-quark mass with Lattice Quantum Chromodynamics. The\ncalculations are performed with an isotropic clover discretization of the quark\naction in three volumes with spatial extents of L \\sim 3.4 fm, 4.5fm and 6.7\nfm, and with a lattice spacing of b \\sim 0.145 fm. With determinations of the\nenergies of the two-nucleon systems (both of which contain bound states at\nthese up and down quark masses) at rest and moving in the lattice volume,\nLuscher's method is used to determine the low-energy phase shifts in each\nchannel, from which the scattering length and effective range are obtained. The\nscattering parameters, in the 1S0 channel are found to be m_pi a^(1S0) =\n9.50^{+0.78}_{-0.69}^{+1.10}_{-0.80} and m_pi r^(1S0) =\n{4.61^{+0.29}_{-0.31}^{+0.24}_{-0.26}, and in the 3S1 channel are m_pi a^(3S1)\n= 7.45^{+0.57}_{-0.53}^{+0.71}_{-0.49} and m_pi r^(3S1) =\n3.71^{+0.28}_{-0.31}^{+0.28}_{-0.35}. These values are consistent with the\ntwo-nucleon system exhibiting Wigner's supermultiplet symmetry, which becomes\nexact in the limit of large-N_c. In both spin channels, the phase shifts change\nsign at higher momentum, near the start of the t-channel cut, indicating that\nthe nuclear interactions have a repulsive core even at the SU(3)-symmetric\npoint."
    },
    {
        "anchor": "Search for the possible S=+1 Pentaquark states in Quenched Lattice QCD: We study spin $\\frac12$ hadronic states in quenched lattice QCD to search for\na possible $S=+1$ pentaquark resonance. Simulations are carried out on\n$8^3\\times 24$, $10^3\\times 24$, $12^3\\times 24$ and $16^3\\times 24$ lattices\nat $\\beta$=5.7 at the quenched level with the standard plaquette gauge action\nand the Wilson quark action. We adopt a Dirichlet boundary condition in the\ntime direction for the quark to circumvent the possible contaminations due to\nthe (anti)periodic boundary condition for the quark field, which are peculiar\nto the pentaquark. By diagonalizing the $2\\times 2$ correlation matrices\nconstructed from two independent operators with the quantum numbers\n$(I,J)=(0,\\frac12)$, we successfully obtain the energies of the lowest state\nand the 2nd-lowest state in this channel. The analysis of the volume dependence\nof the energies and spectral weight factors indicates that a resonance state is\nlikely to exist slightly above the NK threshold in $(I,J^P)=(0,\\frac12^-)$\nchannel.",
        "positive": "Three dimensional finite temperature SU(3) gauge theory in the confined\n  region and the string picture: We determine the correlation between Polyakov loops in three dimensional\nSU(3) gauge theory in the confined region at finite temperature. For this\npurpose we perform lattice calculations for the number of steps in the\ntemperature direction equal to six. This is expected to be in the scaling\nregion of the lattice theory. We compare the results to the bosonic string\nmodel. The agreement is very good for temperatures T<0.7T_c, where T_c is the\ncritical temperature. In the region 0.7T_c<T<T_c we enter the critical region,\nwhere the critical properties of the correlations are fixed by universality to\nbe those of the two dimensional three state Potts model. Nevertheless, by\ncalculating the critical lattice coupling, we show that the ratio of the\ncritical temperature to the square root of the zero temperature string tension,\nwhere the latter is taken from the literature, remains very near to the string\nmodel prediction."
    },
    {
        "anchor": "Chiral symmetry breaking and the Banks--Casher relation in lattice QCD\n  with Wilson quarks: The Banks--Casher relation links the spontaneous breaking of chiral symmetry\nin QCD to the presence of a non-zero density of quark modes at the low end of\nthe spectrum of the Dirac operator. Spectral observables like the number of\nmodes in a given energy interval are renormalizable and can therefore be\ncomputed using the Wilson formulation of lattice QCD even though the latter\nviolates chiral symmetry at energies on the order of the inverse lattice\nspacing. Using numerical simulations, we find (in two-flavour QCD) that the low\nquark modes do condense in the expected way. In particular, the chiral\ncondensate can be accurately calculated simply by counting the low modes on\nlarge lattices. Other spectral observables can be considered as well and have a\npotentially wide range of uses.",
        "positive": "Running coupling of the sextet composite Higgs model: The scale-dependent renormalized coupling of SU(3) gauge theory coupled to Nf\n= 2 flavors of massless Dirac flavors in the sextet representation is presented\nin the range 0 < g^2 < 6.5. This range includes the location where the\nbeta-function turns zero in the MSbar scheme to 3-loop and 4-loop\napproximations, however our non-perturbative result shows a monotonically\nincreasing beta-function. Our lattice calclulations are carried out at several\nlattice spacings allowing for a controlled continuum extrapolation. We also\ncomment on a recent similar calculation by Hasenfratz tet al."
    },
    {
        "anchor": "Using Approximating Polynomials in Partial-Global Dynamical Simulations: Smeared link fermionic actions can be straightforwardly simulated with\npartial-global updating. The efficiency of this simulation is greatly increased\nif the fermionic matrix is written as a product of several near-identical\nterms. Such a break-up can be achieved using polynomial approximations for the\nfermionic matrix. In this paper we will focus on methods of determining the\noptimum polynomials.",
        "positive": "The gradient flow coupling in the Schr\u00f6dinger Functional: We study the perturbative behavior of the Yang-Mills gradient flow in the\nSchr\\\"odinger Functional, both in the continuum and on the lattice. The energy\ndensity of the flow field is used to define a running coupling at a scale given\nby the size of the finite volume box. From our perturbative computation we\nestimate the size of cutoff effects of this coupling to leading order in\nperturbation theory. On a set of Nf=2 gauge field ensembles in a physical\nvolume of L ~ 0.4 fm we finally demonstrate the suitability of the coupling for\na precise continuum limit due to modest cutoff effects and high statistical\nprecision."
    },
    {
        "anchor": "Ratio of kaon and pion leptonic decay constants with $N_f = 2 + 1 + 1$\n  Wilson-clover twisted-mass fermions: We present a determination of the ratio of kaon and pion leptonic decay\nconstants in isosymmetric QCD (isoQCD), $f_K / f_\\pi$, making use of the gauge\nensembles produced by the Extended Twisted Mass Collaboration (ETMC) with $N_f\n= 2 + 1 + 1$ flavors of Wilson-clover twisted-mass quarks, including\nconfigurations close to the physical point for all dynamical flavors. The\nsimulations are carried out at three values of the lattice spacing ranging from\n$\\sim 0.068$ to $\\sim 0.092$ fm with linear lattice size up to $L \\sim 5.5$~fm.\nThe scale is set by the PDG value of the pion decay constant, $f_\\pi^{isoQCD} =\n130.4~(2)$ MeV, at the isoQCD pion point, $M_\\pi^{isoQCD} = 135.0~(2)$ MeV,\nobtaining for the gradient-flow (GF) scales the values $w_0 = 0.17383~(63)$ fm,\n$\\sqrt{t_0} = 0.14436~(61)$ fm and $t_0 / w_0 = 0.11969~(62)$ fm. The data are\nanalyzed within the framework of SU(2) Chiral Perturbation Theory (ChPT)\nwithout resorting to the use of renormalized quark masses. At the isoQCD kaon\npoint $M_K^{isoQCD} = 494.2~(4)$ MeV we get $(f_K / f_\\pi)^{isoQCD} =\n1.1995~(44)$, where the error includes both statistical and systematic\nuncertainties. Implications for the Cabibbo-Kobayashi-Maskawa (CKM) matrix\nelement $|V_{us}|$ and for the first-row CKM unitarity are discussed.",
        "positive": "Non-perturbative thermal QCD at all temperatures: the case of mesonic\n  screening masses: We present a strategy based on the step-scaling technique to study\nnon-perturbatively thermal QCD up to very high temperatures. As a first\nconcrete application, we compute the flavour non-singlet meson screening masses\nat 12 temperatures covering the range from $T \\sim 1$ GeV up to $\\sim 160$ GeV\nin the theory with three massless quarks. The calculation is carried out by\nMonte Carlo simulations on the lattice by considering large spatial extensions\nin order to have negligible finite volume effects. For each temperature we have\nsimulated 3 or 4 values of the lattice spacing, so as to perform the continuum\nlimit extrapolation with confidence at a few permille accuracy. Chiral symmetry\nrestoration manifests itself in our results through the degeneracy of the\nvector and the axial vector channels and of the scalar and the pseudoscalar\nones. In the entire range of temperatures explored, the meson screening masses\ndeviate from the free theory result, $2 \\pi T$, by at most a few percent. These\ndeviations, however, cannot be explained by the known leading term in the QCD\ncoupling constant $g$ up to the highest temperature, where other contributions\nare still very relevant. In particular the vector-pseudoscalar mass splitting\nturns out to be of $O(g^4)$ in the entire range explored, and it remains\nclearly visible up to the highest temperature, where the two screening masses\nare still significantly different within our numerical precision. The pattern\nof different contributions that we have found explains why it has been\ndifficult in the past to match non-perturbative lattice results at $T \\sim 1$\nGeV with the analytic behaviour at asymptotically high temperatures."
    },
    {
        "anchor": "Gauge theories with fermions in the two-index symmetric representation: We summarize our recent work on gauge theories with two flavors of fermions\nin the two-index symmetric representation: SU(2) gauge theory with adjoint\nfermions, SU(3) with sextets, and SU(4) with ten-dimensional-representation\nfermions. All three systems have beta functions smaller than their perturbative\nvalue, approaching a fixed point near the expected two-loop zero. In all cases\nthe mass anomalous dimension is small, under 0.5.",
        "positive": "New insight in the 2-flavor Schwinger model based on lattice simulations: We consider the Schwinger model with two degenerate, light fermion flavors by\nmeans of lattice simulations. At finite temperature, we probe the viability of\na bosonization method by Hosotani et al. Next we explore an analogue to the\npion decay constant, which agrees for independent formulations based on the\nGell-Mann--Oakes--Renner relation, the 2-dimensional Witten--Veneziano formula\nand the $\\delta$-regime. Finally we confront several conjectures about the\nchiral condensate with lattice results."
    },
    {
        "anchor": "Meson and baryon masses with low mode averaging: We describe and test a method known in the literature as low mode averaging\nto improve Euclidean two-point functions in lattice QCD using the low-lying\neigenmodes of the Wilson-Dirac operator D. The contribution from the low modes\nis averaged over all positions of the quark sources while the contribution from\nhigh modes is calculated in the traditional way using one source point per\nlattice. We apply this method to different baryon and meson two-point functions\nand we compare the improvements using the eigenmodes of the non-hermitian\noperator D and the eigenmodes of the hermitian operator Q=gamma5 D. The\nconvergence strongly depends on the parity of the states.",
        "positive": "More chiral operators on the lattice: Instead of the Ginsparg-Wilson (GW) relation we only require generalized\nchiral symmetry and show that this results in a larger class of Dirac operators\ndescribing massless fermions, which in addition to GW fermions and to the ones\nproposed by Fujikawa includes many more general ones. The index turns out to\ndepend solely on a basic unitary operator. We use spectral representations to\nanalyze the new class and to obtain detailed properties. We also show that our\nweaker conditions still lead properly to Weyl fermions and to chiral gauge\ntheories."
    },
    {
        "anchor": "Finite volume effects in SU(2) with two adjoint fermions: Many evidences from lattice simulations support the idea that SU(2) with two\nDirac flavors in the adjoint representation (also called Minimal Walking\nTechnicolor) is IR conformal. A possible way to see this is through the\nbehavior of the spectrum of the mass-deformed theory. When fermions are\nmassive, a mass-gap is generated and the theory is confined. IR-conformality is\nrecovered in the chiral limit: masses of particles vanish in the chiral limit,\nwhile their ratios stay finite. In order to trust this analysis one has to\nrelay on the infinite volume extrapolation. We will discuss the finite volume\neffects on the mesonic spectrum, investigated by varying the size of the\nlattice and by changing the boundary conditions for the fields.",
        "positive": "Domain wall fermion and chiral gauge theories on the lattice with exact\n  gauge invariance: We discuss how to construct anomaly-free chiral gauge theories on the lattice\nwith exact gauge invariance in the framework of domain wall fermion. Chiral\ngauge coupling is realized by introducing a five-dimensional gauge field which\ninterpolates between two different four-dimensional gauge fields at boundaries.\nThe five-dimensional dependence is compensated by a local and gauge-invariant\ncounter term. The cohomology problem to obtain the counter term is formulated\nin 5+1 dimensional space, using the Chern-Simons current induced from the\nfive-dimensional Wilson fermion. We clarify the connection to the invariant\nconstruction based on the Ginsparg-Wilson relation using overlap Dirac\noperator. Formula for the measure and the effective action of Weyl fermions are\nobtained in terms of five-dimensional lattice quantities."
    },
    {
        "anchor": "TWQCD's dynamical DWF project: We present an overview of our project of simulation of unquenched lattice QCD\nwith optimal domain-wall quarks, using a GPU cluster currently constituting of\n16 units of Nvidia Tesla S1070 plus 64 graphic cards with Nvidia GTX285 (total\n128 GPUs with 128 Teraflops peak), attaining sustained computing power of 15.36\nTeraflops. The first production run in two-flavor QCD is on-going, using the\nIwasaki gauge action on a set of lattices with sizes $ 16^3 \\times\n(32,10,8,6,4) \\times (16,32) $ at the lattice spacing $ a \\sim 0.1$ fm, with\neight sea quark masses down to $ m_\\pi \\simeq 200 $ MeV. We outline our\nsimulation algorithm, and describe the present status of the production run.\nPreliminary results of pseudoscalar mass and decay constant are also presented.",
        "positive": "Large-N reduction with adjoint Wilson fermions: We analyze the large-N behavior of SU(N) lattice gauge theories with adjoint\nfermions by studying volume-reduced models, as pioneered by Eguchi and Kawai.\nWe perform simulations on a single-site lattice for Nf = 1 and Nf = 2 Wilson\nDirac fermions with values of N up to 53. We show for both values of Nf that in\nthe large-N limit there is a finite region, containing both light and heavy\nfermions, of unbroken center symmetry where the theory exhibits volume\nindependence. Using large-N reduction we attempt to calculate physical\nquantities such as the string tension and meson masses."
    },
    {
        "anchor": "Generating SU(Nc) pure gauge lattice QCD configurations on GPUs with\n  CUDA: The starting point of any lattice QCD computation is the generation of a\nMarkov chain of gauge field configurations. Due to the large number of lattice\nlinks and due to the matrix multiplications, generating SU(Nc) lattice QCD\nconfigurations is a highly demanding computational task, requiring advanced\ncomputer parallel architectures such as clusters of several Central Processing\nUnits (CPUs) or Graphics Processing Units (GPUs). In this paper we present and\nexplore the performance of CUDA codes for NVIDIA GPUs to generate SU(Nc)\nlattice QCD pure gauge configurations. Our implementation in one GPU uses CUDA\nand in multiple GPUs uses OpenMP and CUDA. We present optimized CUDA codes\nSU(2), SU(3) and SU(4). We also show a generic SU(Nc) code for Nc$\\,\\geq 4$ and\ncompare it with the optimized version of SU(4). Our codes are publicly\navailable for free use by the lattice QCD community.",
        "positive": "Baryon interactions from lattice QCD with physical masses ---\n  strangeness $S=-1$ sector ---: We present our recent results of baryon interactions with strangeness $S=-1$\nbased on Nambu-Bethe-Salpeter (NBS) correlation functions calculated from\nlattice QCD with almost physical quark masses corresponding to\n$(m_\\pi,m_K)\\approx(146,525)$ MeV and large volume $(La)^4=(96a)^4\\approx$ (8.1\nfm)$^4$. In order to perform a comprehensive study of baryon interactions, a\nlarge number of NBS correlation functions from NN to $\\Xi\\Xi$ are calculated\nsimultaneously by using large scale computer resources. In this contribution,\nwe focus on the strangeness $S=-1$ channels of the hyperon interactions by\nmeans of HAL QCD method. Four sets of three potentials (the $^3S_1-^3D_1$\ncentral, $^3S_1-^3D_1$ tensor, and the $^1S_0$ central potentials) are\npresented for the $\\Sigma N - \\Sigma N$ (the isospin $I=3/2$) diagonal, the\n$\\Lambda N - \\Lambda N$ diagonal, the $\\Lambda N \\rightarrow \\Sigma N$\ntransition, and the $\\Sigma N - \\Sigma N$ ($I=1/2$) diagonal interactions.\nScattering phase shifts for $\\Sigma N$ $(I=3/2)$ system are presented."
    },
    {
        "anchor": "The epsilon regime with twisted mass Wilson fermions: We investigate the leading lattice spacing effects in mesonic two-point\ncorrelators computed with twisted mass Wilson fermions in the epsilon-regime.\nBy generalizing the procedure already introduced for the untwisted Wilson\nchiral effective theory, we extend the continuum chiral epsilon expansion to\ntwisted mass WChPT. We define different regimes, depending on the relative\npower counting for the quark masses and the lattice spacing. We explicitly\ncompute, for arbitrary twist angle, the leading O(a^2) corrections appearing at\nNLO in the so-called GSM^* regime. As in untwisted WChPT, we find that in this\nsituation the impact of explicit chiral symmetry breaking due to lattice\nartefacts is strongly suppressed. Of particular interest is the case of maximal\ntwist, which corresponds to the setup usually adopted in lattice simulations\nwith twisted mass Wilson fermions. The formulae we obtain can be matched to\nlattice data to extract physical low energy couplings, and to estimate\nsystematic uncertainties coming from discretization errors.",
        "positive": "The triviality bound on the Higgs mass; its value and what it means: Older lattice work exploring the Higgs mass triviality bound is briefly\nreviewed. It indicates that a strongly interacting scalar sector in the minimal\nstandard model cannot exist; on the other hand low energy QCD phenomenology\nmight be interpreted as an indication that it could. We attack this puzzle\nusing the $1/N$ expansion and discover a simple criterion for selecting a\nlattice action that is more likely to produce a heavy Higgs particle. Depending\non the precise form of the limitation put on the cutoff effects, our large $N$\ncalculations, when combined with old numerical data, suggest that the Higgs\nmass bound might be around 750 $GeV$, which is higher than the $\\sim 650~GeV$\npreviously obtained. Preliminary numerical work indicates that an increase of\nat least 19\\% takes place at $N=4$ on the $F_4$ lattice when the old simple\naction is replaced with a new action (still containing only nearest neighbor\ninteractions) if one uses the lattice spacing as the physical cutoff for both\nactions. It appears that, while a QCD like theory could produce $M_H / F ~ \\sim\n6$, a meaningful ``minimal elementary Higgs'' theory cannot have $M_H/ F~\n\\gtapprox 3$. Still, even at 750 $GeV$, the Higgs particle is so wide ($\\sim\n290~$GeV), that one cannot argue any more that the scalar sector is weakly\ncoupled."
    },
    {
        "anchor": "Antisymmetric and other subleading corrections to scaling in the local\n  potential approximation: For systems in the universality class of the three-dimensional Ising model we\ncompute the critical exponents in the local potential approximation (LPA), that\nis, in the framework of the Wegner-Houghton equation. We are mostly interested\nin antisymmetric corrections to scaling, which are relatively poorly studied.\nWe find the exponent for the leading antisymmetric correction to scaling\n$\\omega_A \\approx 1.691$ in the LPA. This high value implies that such\ncorrections cannot explain asymmetries observed in some Monte Carlo\nsimulations.",
        "positive": "Numerical results for the lightest bound states in $\\mathcal{N}=1$\n  supersymmetric SU(3) Yang-Mills theory: The physical particles in supersymmetric Yang-Mills theory (SYM) are bound\nstates of gluons and gluinos. We have determined the masses of the lightest\nbound states in SU(3) $\\mathcal{N}=1$ SYM. Our simulations cover a range of\ndifferent lattice spacings, which for the first time allows an extrapolation to\nthe continuum limit. Our results show the formation of a supermultiplet of\nbound states, which provides a clear evidence for unbroken supersymmetry."
    },
    {
        "anchor": "Accurate simulation of the finite density lattice Thirring model: We present a study of the finite density lattice Thirring model in 1+1\ndimensions using the world-line/fermion-bag algorithm. The model has features\nsimilar to QCD and provides a test case for exploring the accuracy of various\nmethods of solving sign problems. In the massless limit and with open boundary\nconditions we show that the sign problem is an artifact of the auxiliary field\napproach and is completely eliminated in the fermion bag approach. With\nperiodic boundary conditions the sign problem is mild in the fermion bag\nmethod. We present accurate results for various quantities in the model that\ncan be used as a benchmark for comparison with other methods of solving sign\nproblems.",
        "positive": "Loop representation for 2-D Wilson lattice fermions in a scalar\n  background field: We show that the fermion determinant for 2-D Wilson lattice fermions coupled\nto an external scalar field is equivalent to self avoiding loops interacting\nwith the external field. In an application of the resulting formula we\nintegrate the scalar field with a Gaussian action to generate the N-component\nGross-Neveu model. The loop representation for this model is discussed."
    },
    {
        "anchor": "$\u039b_b \\to \u039b\\ell^+ \\ell^-$ form factors, differential\n  branching fraction, and angular observables from lattice QCD with\n  relativistic $b$ quarks: Using $(2+1)$-flavor lattice QCD, we compute the 10 form factors describing\nthe $\\Lambda_b \\to \\Lambda$ matrix elements of the $b \\to s$ vector, axial\nvector, and tensor currents. The calculation is based on gauge field ensembles\ngenerated by the RBC and UKQCD Collaborations with a domain-wall action for the\n$u$, $d$, and $s$ quarks and the Iwasaki gauge action. The $b$ quark is\nimplemented using an anisotropic clover action, tuned nonperturbatively to the\nphysical point, and the currents are renormalized with a mostly nonperturbative\nmethod. We perform simultaneous chiral, continuum, and kinematic extrapolations\nof the form factors through modified $z$ expansions. Using our form factor\nresults, we obtain precise predictions for the $\\Lambda_b \\to \\Lambda(\\to p^+\n\\pi^-) \\mu^+ \\mu^-$ differential branching fraction and angular observables in\nthe Standard Model.",
        "positive": "Study of 3-flavor QCD Finite Temperature Phase Transition with Staggered\n  Fermions: We have studied the 3-flavor, finite temperature, QCD phase transition with\nstaggred fermions on an $ N_t=4$ lattice. By studying a variety of quark masses\nwe have located the critical point, $m_c$, where the first order 3-flavor\ntransition ends as lying in the region $0.32 \\le m_c \\le 0.35$ in lattice units"
    },
    {
        "anchor": "Two-dimensional model of dynamical fermion mass generation in strongly\n  coupled gauge theories: We generalize the $N_F=2$ Schwinger model on the lattice by adding a charged\nscalar field. In this so-called $\\chi U\\phi_2$ model the scalar field shields\nthe fermion charge, and a neutral fermion, acquiring mass dynamically, is\npresent in the spectrum. We study numerically the mass of this fermion at\nvarious large fixed values of the gauge coupling by varying the effective\nfour-fermion coupling, and find an indication that its scaling behavior is the\nsame as that of the fermion mass in the chiral Gross-Neveu model. This suggests\nthat the $\\chi U\\phi_2$ model is in the same universality class as the\nGross-Neveu model, and thus renormalizable and asymptotic free at arbitrary\nstrong gauge coupling.",
        "positive": "On the infrared behavior of Green's functions in Yang-Mills theory: Non-perturbative properties of QCD, such as color confinement, are encoded in\nthe infrared behavior of correlation functions, e.g. propagators and vertices.\nVarious analytic predictions have been suggested for these quantities in\nvarious gauges. Here we numerically test these predictions using lattice gauge\ntheory. In particular, we present results for the 2- and 3-point functions for\nSU(2) Landau-gauge Yang-Mills theory in three and in four dimensions. Special\nattention is paid to systematic finite-volume effects. The gluon and ghost\npropagators are also evaluated in the so-called interpolating gauge (between\nthe Landau and the Coulomb gauge), in order to study their gauge-dependence.\nFinally, we consider these propagators in Landau gauge at finite temperature,\nwith the aim of understanding the effect of the deconfinement phase transition\non their infrared behavior. All our results are compatible with the so-called\nGribov-Zwanziger confinement scenario."
    },
    {
        "anchor": "Toward a novel determination of the strong QCD coupling at the Z-pole: We test here our recently introduced new lattice method for the\n$\\beta$-function defined over infinite Euclidean space-time in the continuum\nfrom scale changes generated by infinitesimal or finite steps of the\nrenormalized gauge coupling on the gradient flow. Harlander and Neumann\ncalculated in this scheme the three-loop approximation to the continuum\n$\\beta$-function. Our goal is the nonperturbative lattice implementation of the\nscheme which we tested originally in the chiral limit of the sextet model and\nin multi-flavor QCD with ten and twelve flavors of massless fermions. Results\nare reported here in the SU(3) Yang-Mills gauge sector without dynamical\nfermions and in ten-flavor QCD with massless femions. The three-loop gradient\nflow based $\\beta$-function of Harlander and Neumann is used to connect the\n$\\Lambda_{\\overline{\\rm MS}}$ scale of the SU(3) Yang-Mills gauge theory with\nthe nonperturbative flow time scale $t_0$, or the equivalent Sommer scale\n$r_0$. Similarly, the $\\Lambda_{\\overline{\\rm MS}}$ scale is connected with a\nselected nonperturbative scale in the ten-flavor theory, a pilot study of our\nnew lattice based nonperturbative $\\beta$-function for high precision\ndetermination of the strong coupling $\\alpha_s$ at the Z-boson pole in QCD with\nthree massless fermion flavors. This goal is an important alternative to\nresults from the finite volume based step $\\beta$-function of the Alpha\ncollaboration. Work is ongoing on direct application of the method to QCD with\nthree massless fermion flavors.",
        "positive": "Asymptotic safety on the lattice: The Nonlinear O(N) Sigma Model: We study the non-perturbative renormalization group flow of the nonlinear\nO(N) sigma model in two and three spacetime dimensions using a scheme that\ncombines an effective local Hybrid Monte Carlo update routine, blockspin\ntransformations and a Monte Carlo demon method. In two dimensions our results\nverify perturbative renormalizability. In three dimensions, we determine the\nflow diagram of the theory for various $N$ and different truncations and find a\nnon-trivial fixed point, which indicates non-perturbative renormalizability. It\nis related to the well-studied phase transition of the O(N) universality class\nand characterizes the continuum physics of the model. We compare the obtained\nrenormalization group flows with recent investigations by means of the\nFunctional Renormalization Group."
    },
    {
        "anchor": "Recent results from systematic parameterizations of Ginsparg-Wilson\n  fermions: The Fixed Point Dirac Operator and Chirally Improved Fermions both use large\nnumbers of gauge paths and the full Dirac structure to approximate a solution\nof the Ginsparg-Wilson equation. After a brief review of the two approaches we\npresent recent results for quenched QCD with pion masses down to 210 MeV. We\ndiscuss the limits and advantages of approximate parameterizations and outline\nfuture perspectives.",
        "positive": "Lattice spectroscopy with focus on exotics: Recent lattice QCD results on the hadron spectroscopy with beauty and charm\nquarks is reviewed. The focus of the review are exotic hadrons, while\nnon-lattice approaches and conventional hadrons are reported as well. We\ndiscuss the recently discovered $\\Omega_c^*$, a charmonium state with spin\nthree, $P_c$ pentaquarks, $B_c(2S)$ and $\\Lambda_b^*$, the long-standing\nchallenges for theory $Z_c$, $Z_b$ and $X(3872)$, and we review predictions for\nyet undiscovered states $bb\\bar q\\bar q$, $\\bar bb\\bar bb$, highly excited and\nhybrid $\\bar bb$, baryons with bottom quarks and still-missing $B_{s}$ mesons."
    },
    {
        "anchor": "The chiral and angular momentum content of the rho-meson: It is possible to define and calculate in a gauge-invariant manner the chiral\nas well as the partial wave content of the quark-antiquark Fock component of a\nmeson in the infrared, where mass is generated. Using the variational method\nand a set of interpolators that span a complete chiral basis we extract in a\nlattice QCD Monte Carlo simulation with two dynamical light quarks the orbital\nangular momentum and spin content of the rho-meson. We obtain in the infrared a\nsimple 3S1 component as a leading component of the rho-meson with a small\nadmixture of the 3D1 partial wave, in agreement with the SU(6) flavor-spin\nsymmetry.",
        "positive": "Critical Exponents of the Three Dimensional Random Field Ising Model: The phase transition of the three--dimensional random field Ising model with\na discrete ($\\pm h$) field distribution is investigated by extensive Monte\nCarlo simulations. Values of the critical exponents for the correlation length,\nspecific heat, susceptibility, disconnected susceptibility and magnetization\nare determined simultaneously via finite size scaling. While the exponents for\nthe magnetization and disconnected susceptibility are consistent with a first\norder transition, the specific heat appears to saturate indicating no latent\nheat. Sample to sample fluctuations of the susceptibilty are consistent with\nthe droplet picture for the transition."
    },
    {
        "anchor": "Visualizing resonances in finite volume: In present work, we explore and experiment an alternative approach of\nstudying resonance properties in finite volume. By analytic continuing finite\nlattice size $L$ into complex plane, the oscillating behavior of finite volume\nGreen's function is mapped into infinite volume Green's function corrected by\nexponentially decaying finite volume effect. The analytic continuation\ntechnique thus can be applied to study resonance properties directly in finite\nvolume dynamical equations.",
        "positive": "Efficiencies and optimization of HMC algorithms in pure gauge theory: As a prerequisite to dynamical fermion simulations a detailed study of\noptimal parameters and scaling behavior is conducted for the quenched\nSchr\\\"odinger functional at fixed renormalized coupling. We compare standard\nhybrid overrelaxation techniques with local and global hybrid Monte Carlo. Our\nefficiency measure is designed to be directly relevant for the strong coupling\nconstant as used by the ALPHA collaboration."
    },
    {
        "anchor": "Adaptive Step Size for Hybrid Monte Carlo Algorithm: We implement an adaptive step size method for the Hybrid Monte Carlo a\nlgorithm. The adaptive step size is given by solving a symmetric error\nequation. An integr ator with such an adaptive step size is reversible.\nAlthough we observe appreciable variations of the step size, the overhead of\nthe method exceeds its benefits. We propose an explanation for this phenomenon.",
        "positive": "Determination of the charm quark mass in lattice QCD with $2+1$ flavours\n  on fine lattices: We present a determination of the charm quark mass in lattice QCD with three\nactive quark flavours. The calculation is based on PCAC masses extracted from\n$N_\\mathrm{f}=2+1$ flavour gauge field ensembles at five different lattice\nspacings in a range from 0.087 fm down to 0.039 fm. The lattice action consists\nof the $\\mathrm{O}(a)$ improved Wilson-clover action and a tree-level improved\nSymanzik gauge action. Quark masses are non-perturbatively $\\mathrm{O}(a)$\nimproved employing the Symanzik-counterterms available for this discretisation\nof QCD. To relate the bare mass at a specified low-energy scale with the\nrenormalisation group invariant mass in the continuum limit, we use the\nnon-pertubatively known factors that account for the running of the quark\nmasses as well as for their renormalisation at hadronic scales. We obtain the\nrenormalisation group invariant charm quark mass at the physical point of the\nthree-flavour theory to be $M_\\mathrm{c} = 1486(21)\\,\\mathrm{MeV}$. Combining\nthis result with five-loop perturbation theory and the corresponding decoupling\nrelations in the $\\overline{\\mathrm{MS}}$ scheme, one arrives at a result for\nthe renormalisation group invariant charm quark mass in the four-flavour theory\nof $M_\\mathrm{c}(N_\\mathrm{f}=4) = 1548(23)\\,\\mathrm{MeV}$. In the\n$\\overline{\\mathrm{MS}}$ scheme, and at finite energy scales conventional in\nphenomenology, we quote\n$m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}}(m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}};\nN_\\mathrm{f}=4)=1296(19)\\,\\mathrm{MeV}$ and\n$m^{\\overline{\\mathrm{MS}}}_{\\mathrm{c}}(3\\,\\mathrm{GeV};\nN_\\mathrm{f}=4)=1007(16)\\,\\mathrm{MeV}$ for the renormalised charm quark mass"
    },
    {
        "anchor": "Lattice studies of charmonia and exotics: The lattice QCD simulations of charmonia and exotic charmonium-like states\nare reviewed. I report on the first exploratory simulation of charmonium\nresonances above open charm threshold which takes into account the strong\ndecay. The puzzles related to the first-excited scalar charmonia are discussed.\nEvidence for X(3872) is presented along with investigation of its Fock\ncomponents. The $Z_c^+(3900)$ seems to emerge from the HALQCD approach as a\nresult of the coupled channel effect $J/\\psi \\pi -D\\bar D^*$. The indication\nfor the pentaquark bound state $\\eta_c N$ is presented.",
        "positive": "New Abelian-like monopoles and the dual Meissner effect: Violation of non-Abelian Bianchi identity can be regarded as $N^2-1$\nAbelian-like monopole currents in the continuum SU(N) QCD. Three Abelian-like\nmonopoles, when defined in SU(2) gluodynamics on the lattice \\`{a} la\nDeGrand-Toussaint, are shown to have the continuum limit with respect to the\ncolor-invariant monopole density and the effective monopole action. Since each\nAbelian-like monopole is not gauge invariant, we have introduced various\npartial gauge fixing for the purpose of reducing lattice artifact monopoles in\nthe thermalized vacuum. Here we investigate Abelian and monopole dominances and\nthe Abelian dual Meissner effects adopting the same gauges like the maximal\ncenter gauge (MCG) in comparison with the maximal Abelian gauge (MAG). Abelian\nand monopole contributions to the string tension in these gauges are observed\nto be a little smaller than the non-Abelian string tension. However, we find\nthat the monopole dominance is improved well when use is made of the block-spin\ntransformations with respect to Abelian-like monopoles. We find each electric\nfield is squeezed by the corresponding colored Abelian-like monopole in such\ngauges and the Abelian dual Meissner effect is observed independently for each\ncolor. Moreover, we confirm the dual Amp\\`{e}re's law in these new gauges as\nwell as in MAG. The SU(2) vacuum is shown to be near the border between the\ntype 1 and type 2 dual superconductors. The penetration length is almost equal\nfor the four gauge fixings and the vacuum type in MCG is almost the same value\nas the previous results. These results are consistent with the previous results\nsuggesting the continuum limit and the gauge-independence of Abelian monopoles."
    },
    {
        "anchor": "An Investigation of the Soft Pion Relation in Quenched Lattice QCD: A lattice determination of the form factor and decay constants for the\nsemileptonic decay of heavy pseudoscalar (PS) mesons at zero recoil is\npresented from which the soft pion relation is satisfied. Chiral extrapolation\nof the form factor is performed at constant $q^2$. Pole dominance is used to\nextrapolate the form factor in heavy quark mass. At the B mass, the form factor\nat zero recoil lies somewhat below the ratio of decay constants; the relation\nremains satisfied within error.",
        "positive": "Quenched chiral logarithms in lattice QCD with overlap Dirac quarks: We examine quenched chiral logarithms in lattice QCD with overlap Dirac\nquarks. From our data of m_pi^2, we determine the coefficient of quenched\nchiral logarithm delta = 0.203(14), 0.176(17), 0.193(17) and 0.200(13) for\nlattices of sizes 8^3 times 24, 10^3 times 24, 12^3 times 24 and 16^3 times 32\nrespectively. Also, for the first three lattice sizes, we measure the index\nsusceptibility of the overlap Dirac operator, and use the exact relation\nbetween the index susceptibility and the eta' mass in quenched chiral\nperturbation theory to obtain an independent determination of delta =\n0.198(27), 0.173(24), 0.169(22), which are in good agreement with those\ndetermined from m_pi^2."
    },
    {
        "anchor": "Anomaly non-renormalization, lattice QFT and universality of transport\n  coefficients: Recently new methods have been introduced to investigate the\nnon-renormalization properties of the anomalies at a non perturbative level and\nin presence of a lattice. The issue is relevant in a number of problems ranging\nfrom the anomaly-free construction of chiral lattice gauge theory with large\ncut-off to the universality properties observed in transport coefficients in\ncondensed matter systems. A review of main results and future perspectives is\npresented.",
        "positive": "Hybrid configuration content of heavy S-wave mesons: We use the non-relativistic expansion of QCD (NRQCD) on the lattice to study\nthe lowest hybrid configuration contribution to the ground state of heavy\nS-wave mesons. Using lowest-order lattice NRQCD to create the heavy-quark\npropagators, we form a basis of ``unperturbed'' S-wave and hybrid states. We\nthen apply the lowest-order coupling of the quark spin and chromomagnetic field\nat an intermediate time slice to create ``mixed'' correlators between the\nS-wave and hybrid states. From the resulting amplitudes, we extract the\noff-diagonal element of our two-state Hamiltonian. Diagonalizing this\nHamiltonian gives us the admixture of hybrid configuration within the meson\nground state. The present effort represents a continuation of previous work:\nthe analysis has been extended to include lattices of varying spacings, source\noperators having better overlap with the ground states, and the pseudoscalar\n(along with the vector) channel. Results are presented for bottomonium\n($\\Upsilon$, $\\eta_b^{}$) using three different sets of quenched lattices. We\nalso show results for charmonium ($J/\\psi$, $\\eta_c^{}$) from one lattice set,\nalthough we note that the non-relativistic approximation is not expected to be\nvery good in this case."
    },
    {
        "anchor": "Lattice QCD Calculation of Electroweak Box Contributions to Superallowed\n  Nuclear and Neutron Beta Decays: We present the first lattice QCD calculation of the universal axial $\\gamma\nW$-box contribution $\\square_{\\gamma W}^{VA}$ to both superallowed nuclear and\nneutron beta decays. This contribution emerges as a significant component\nwithin the theoretical uncertainties surrounding the extraction of $|V_{ud}|$\nfrom superallowed decays. Our calculation is conducted using two domain wall\nfermion ensembles at the physical pion mass. To construct the nucleon 4-point\ncorrelation functions, we employ the random sparsening field technique.\nFurthermore, we incorporate long-distance contributions to the hadronic\nfunction using the infinite-volume reconstruction method. Upon performing the\ncontinuum extrapolation, we arrive at $\\square_{\\gamma\nW}^{VA}=3.65(8)_{\\mathrm{lat}}(1)_{\\mathrm{PT}}\\times10^{-3}$. Consequently,\nthis yields a slightly higher value of\n$|V_{ud}|=0.97386(11)_{\\mathrm{exp.}}(9)_{\\mathrm{RC}}(27)_{\\mathrm{NS}}$,\nreducing the previous $2.1\\sigma$ tension with the CKM unitarity to\n$1.8\\sigma$. Additionally, we calculate the vector $\\gamma W$-box contribution\nto the axial charge $g_A$, denoted as $\\square_{\\gamma W}^{VV}$, and explore\nits potential implications.",
        "positive": "Modeling the Landau-Gauge Ghost Propagator in 2, 3 and 4 Space-Time\n  Dimensions: We present an analytic description of numerical results for the ghost\npropagator G(p^2) in minimal Landau gauge on the lattice. The data were\nproduced in the SU(2) case using the largest lattice volumes to date, for d =\n2, 3 and 4 space-time dimensions. Our proposed form for G(p^2) is derived from\nthe one-loop relation between ghost and gluon propagators, considering a\ntree-level ghost-gluon vertex and our previously obtained gluon-propagator\nresults \\cite{Cucchieri:2011ig}. Although this one-loop expression is not a\ngood description of the data, it leads to a one-parameter fit of our\nghost-propagator data with a generally good value of \\chi^2/dof, comparable to\nother fitting forms used in the literature. At the same time, we present a\nsimple parametrization of the difference between the lattice data and the\none-loop predictions."
    },
    {
        "anchor": "Twisted supersymmetric sigma model on the lattice: In this paper we conduct a numerical study of the supersymmetric O(3)\nnon-linear sigma model. The lattice formulation we employ was derived in\n\\cite{sigma1} and corresponds to a discretization of a {\\it twisted} form of\nthe continuum action. The twisting process exposes a {\\it nilpotent}\nsupercharge $Q$ and allows the action to be rewritten in $Q$-exact form. These\nproperties may be maintained on the lattice. We show how to deform the theory\nby the addition of potential terms which preserve the supersymmetry. A Wilson\nmass operator may be introduced in this way with a minimal breaking of\nsupersymmetry. We additionally show how to rewrite the theory in the language\nof K\\\"{a}hler-Dirac fields and explain why this avenue does not provide a good\nroute to discretization. Our numerical results provide strong evidence for a\nrestoration of full supersymmetry in the continuum limit {\\it without} fine\ntuning. We also observe a non-vanishing chiral condensate as expected from\ncontinuum instanton calculations.",
        "positive": "SU(2) vacuum dynamics in applied external magnetic field: The vacuum dynamics of SU(2) lattice gauge theory is studied by means of a\ngauge-invariant effective action, both at zero and finite temperature. Working\nwith lattices up to 32^4 we check the scaling of the energy density with the\nmagnetic length. We find that the screening at zero temperature of the applied\nexternal magnetic field weakens by increasing the temperature."
    },
    {
        "anchor": "Lattice Monte Carlo methods for systems far from equilibrium: We present a new numerical Monte Carlo approach to determine the scaling\nbehavior of lattice field theories far from equilibrium. The presented methods\nare generally applicable to systems where classical-statistical fluctuations\ndominate the dynamics. As an example, these methods are applied to the\nrandom-force-driven one-dimensional Burgers' equation - a model for\nhydrodynamic turbulence. For a self-similar forcing acting on all scales the\nsystem is driven to a nonequilibrium steady state characterized by a Kolmogorov\nenergy spectrum. We extract correlation functions of single- and multi-point\nquantities and determine their scaling spectrum displaying anomalous scaling\nfor high-order moments. Varying the external forcing we are able to tune the\nsystem continuously from equilibrium, where the fluctuations are short-range\ncorrelated, to the case where the system is strongly driven in the infrared. In\nthe latter case the nonequilibrium scaling of small-scale fluctuations are\nshown to be universal.",
        "positive": "A Lattice Computation of the Decay Constants of $B$ and $D$ Mesons: A lattice calculation of the pseudoscalar decay constant of heavy-light\nmesons is reported. Results are obtained (in the quenched approximation) from\nlattices at $\\beta=6.3$ through a procedure that interpolates between the\nstatic approximation of Eichten and the conventional (\"heavy\" Wilson fermion)\nmethod. The previously observed discrepancy between these two approaches has\nbeen resolved: we find the scaling quantity $f\\sqrt{M}$ to be significantly\nsmaller than previous calculations had indicated ({\\it e.g.} at $\\beta=6.0$);\nin addition, we discuss a modification which is required in normalizing the\nconventional amplitude to correct for large-$am$ lattice errors. This change\nguarantees that $f\\sqrt{M}$ will smoothly approach its value in the static\nlimit. From the numerical interpolation of the static and intermediate-mass\nresults, we find, in units of MeV, $f_B=187(10)\\pm34\\pm15$,\n$f_{B_s}=207(9)\\pm34\\pm22$, $f_D=208(9)\\pm35\\pm12$ and\n$f_{D_s}=230(7)\\pm30\\pm18$, where the first error is statistical and the second\ntwo are estimates of systematics due to 1) fitting and large-$am$ effects and\n2) scaling. In addition, using lattices at $\\beta=6.3$, $\\beta=6.0$ and\n$\\beta=5.7$ and extrapolating to the limit of zero lattice spacing, we have\ncomputed $f_K/f_\\pi = 1.08\\pm.03\\pm.08$ in the quenched approximation."
    },
    {
        "anchor": "Matter on granular space-time: We develop further the formalism of the non-Abelian gauge field theory on a\ncell complex space-time and show how the gauge-invariant action and the\nequations of motion for gauge fields interacting with spinors can be written\nwithout a reference to the geometrical nature of the cells of the cell complex.\nThe general results are illustrated with examples of solutions of equations of\nmotion for U(N) and SU(N) gauge groups.",
        "positive": "Correlation functions of the energy-momentum tensor in SU(2) gauge\n  theory at finite temperature: We calculate correlation functions of the energy-momentum tensor in the\nvicinity of the deconfinement phase transition of (3+1)-dimensional SU(2) gauge\ntheory and discuss their critical behavior in the vicinity of the second order\ndeconfinement transition. We show that correlation functions of the trace of\nthe energy momentum tensor diverge uniformly at the critical point in\nproportion to the specific heat singularity. Correlation functions of the\npressure, on the other hand, stay finite at the critical point. We discuss the\nconsequences of these findings for the analysis of transport coefficients, in\nparticular the bulk viscosity, in the vicinity of a second order phase\ntransition point."
    },
    {
        "anchor": "Spectrum of 4d N=1 SYM on the lattice with light dynamical Wilson\n  gluinos: We perform Monte Carlo investigations of the 4d ${\\cal N}=1$ supersymmetric\nYang-Mills (SYM) theory on the lattice with dynamical gluinos in the adjoint\nrepresentation of the SU(2) gauge group. Our aim is to determine the mass\nspectrum of the low-lying bound states which is expected to be organised in\nsupermultiplets in the infinite volume continuum limit. For this purpose we\nperform simulations on large lattices, up to an extension $L/r_0 \\simeq 6$\nwhere $r_0 \\simeq 0.5 \\rm fm$ is the Sommer scale parameter. We apply improved\nlattice actions: tree-level improved Symanzik (tlSym) gauge action and in the\nlater runs a Stout-smeared Wilson fermion action. The gauge configuration\nsamples are prepared by the Two-Step Polynomial Hybrid Monte Carlo (TS-PHMC)\nupdate algorithm.",
        "positive": "The analytic structure of the Landau gauge quark propagator from Pad\u00e9\n  analysis: The analytic structure of the 2 flavour full QCD lattice Landau gauge quark\npropagator is investigated with Pad\\'e approximants applied to its vector and\nscalar form factors. No poles at complex momentum are observed for the\npropagator. Moreover, there is clear evidence of a pole at real on-axis\nnegative Euclidean momentum, i.e. for Minkowski type of momentum. %, with a\npositive residuum. This pole occurs at Euclidean momenta $p^2 \\sim - 300$ MeV\nand it reproduces typical quark mass values used in phenomenological effective\nquark models. The Pad\\'e approximant analysis also gives hints on the presence\nof a branch cut. Our results also show a clear correlation between the position\nof this pole, understood as an effective quark mass, and the pion mass that is\ncompatible with PCAC. Slightly differences between the poles for the two quark\nform factors are observed which can be viewed either as a limitation of the\nmethod or as a suggestion that the quark propagator has no spectral\nrepresentation."
    },
    {
        "anchor": "Critical analysis of topological charge determination in the background\n  of center vortices in SU(2) lattice gauge theory: We analyze topological charge contributions from classical SU(2) center\nvortices with shapes of planes and spheres using different topological charge\ndefinitions, namely the center vortex picture of topological charge, a discrete\nversion of F\\~{F} in the plaquette and hypercube definitions and the lattice\nindex theorem. For the latter the zeromodes of the Dirac operator in the\nfundamental and adjoint representations using both the overlap and asqtad\nstaggered fermion formulations are investigated. We find several problems for\nthe individual definitions and discuss the discrepancies between the different\ntopological charge definitions. Our results show that the interpretation of\ntopological charge in the background of center vortices is rather subtle.",
        "positive": "Dimensional reduction of Lattice Gauge Theory in (2+1)D: This is my Ph.D. thesis defended earlier this year. It contains mostly\ninformation already presented in previous Bielefeld/Saclay papers on this\nsubject, though in more detailed form. It also includes actual calculations and\nsome unpublished material on phase structure of the reduced model."
    },
    {
        "anchor": "Observing Long Colour Flux Tubes in SU(2) Lattice Gauge Theory: We present results of a high statistics study of the chromo field\ndistribution between static quarks in SU(2) gauge theory on lattices of volumes\n16^4, 32^4, and 48^3*64, with physical extent ranging from 1.3 fm up to 2.7 fm\nat beta=2.5, beta=2.635, and beta=2.74. We establish string formation over\nphysical distances as large as 2 fm. The results are tested against Michael's\nsum rules. A detailed investigation of the transverse action and energy flux\ntube profiles is provided. As a by-product, we obtain the static lattice\npotential in unpreceded accuracy.",
        "positive": "B_K with dynamical overlap fermions: We report on a calculation of $B_K$ with two-flavor dynamical overlap\nfermions on a $16^3 \\times 32$ lattice at $a\\sim 0.12$ fm. The results are\ncompared with the PQChPT prediction of quark mass dependence. The systematic\nerrors due to finite volume effects and fixing topology are discussed."
    },
    {
        "anchor": "Lattice QCD study of mixed systems of pions and kaons: The different ground state energies of N-pion and M-kaon systems for N+M <=12\nare studied in lattice QCD. These energies are then used to extract the various\ntwo- and three- body interactions that occur in these systems. Particular\nattention is paid to additional thermal states present in the spectrum because\nof the finite temporal extent. These calculations are performed using one\nensemble of 2+1 flavor anisotropic lattices with a spatial lattice spacing a_s\n~ 0.125 fm, an anisotropy factor {\\xi}=a_s/a_t=3.5, and a spatial volume L^3 ~\n(2.5 fm)^3. The quark masses used correspond to pion and kaon masses of m_{\\pi}\n~ 383 MeV and m_K ~ 537 MeV, respectively. The isospin and strangeness chemical\npotentials of these systems are found to be in the region where chiral\nperturbation theory and hadronic models predict a phase transition between a\npion condensed phase and a kaon condensed phase.",
        "positive": "Running coupling in SU(2) gauge theory with two adjoint fermions: We study SU(2) gauge theory with two Dirac fermions in the adjoint\nrepresentation of the gauge group on the lattice. Using clover improved Wilson\nfermion action with hypercubic truncated stout smearing we perform simulations\nat larger coupling than earlier. We measure the evolution of the coupling\nconstant using the step scaling method with Schr\\\"odinger functional and study\nthe remaining discretization effects. At weak coupling we observe significant\ndiscretization effects, which make it difficult to obtain a fully controlled\ncontinuum limit. Nevertheless, the data remains consistent with the existence\nof a fixed point in the interval $2.2\\lesssim g^{\\ast 2}\\lesssim 3$. We also\nmeasure the anomalous dimension and find its value at the fixed point is\n$\\gamma^\\ast\\simeq 0.2\\pm 0.03$."
    },
    {
        "anchor": "Yang-Lee zeros of a random matrix model for QCD at finite density: We study the Yang-Lee zeros of a random matrix partition function with the\nglobal symmetries of the QCD partition function. We consider both zeros in the\ncomplex chemical potential plane and in the complex mass plane. In both cases\nwe find that the zeros are located on a curve. In the thermodynamic limit, the\nzeros appear to merge to form a cut. The shape of this limiting curve can be\nobtained from a saddle-point analysis of the partition function. An explicit\nsolution for the line of zeros in the complex chemical potential plane at zero\nmass is given in the form of a transcendental equation.",
        "positive": "Strong coupling series for QCD at finite temperature and density: We discuss the use of strong coupling expansions for Yang-Mills theory and\nQCD at finite temperature and density. In particular we consider the onset of\ntemperature effects for the free energy and screening masses, derive the hadron\nresonance gas model from first principles and compute the weakening of the\ndeconfinement transition with chemical potential."
    },
    {
        "anchor": "Gauge fixing, families index theory, and topological features of the\n  space of lattice gauge fields: The families index theory for the overlap lattice Dirac operator is applied\nto derive topological features of the space of SU(N) lattice gauge fields on\nthe 4-torus: The topological sectors, specified by the fermionic topological\ncharge, are shown to contain noncontractible even-dimensional spheres when\n$N\\ge3$, and noncontractible circles in the N=2 case. We describe how certain\nobstructions to the existence of gauge fixings without the Gribov problem in\nthe continuum setting correspond on the lattice to obstructions to the\ncontractibility of these spheres and circles. We also point out a canonical\nconnection on the space of lattice gauge fields with monopole-like\nsingularities associated with the spheres.",
        "positive": "A first study of the semi-leptonic decay of the $\u039b_b$ baryon: We present the preliminary results of the first Lattice study of the baryonic\nIsgur and Wise function obtained from the matrix element of the weak current\nbetween $\\Lambda$-baryon external states. Its dependence on the heavy and light\nquark masses is studied. Some result on the semi-leptonic decay\n$\\Lambda_b\\to\\Lambda_c +l\\nu$ are given."
    },
    {
        "anchor": "Composite reweighting with Imaginary Chemical Potentials in SU(3): We review the overlap pathology of the Glasgow reweighting method for finite\ndensity QCD, and discuss the sampling bias that effects the determination of\nthe ensemble-averaged fugacity polynomial expansion coefficients that form the\nGrand Canonical Partition function. The expectation of the difference in free\nenergies between canonical partition functions generated with different\nmeasures is presented as an indicator of a systematic quark number dependent\nbiasing in the reweighting approach. The advantages of building up an unbiased\npolynomial expansion for the Grand Canonical Partition function through a\nseries of parallel ensembles generated by reweighting with imaginary chemical\npotentials are then contrasted with addressing the overlap pathology through a\nsecondary reweighting.",
        "positive": "Numerical Simulations in Particle Physics: Numerical simulations have become an important tool to understand and predict\nnon-perturbative phenomena in particle physics. In this article we attempt to\npresent a general overview over the field. First, the basic concepts of lattice\ngauge theories are described, including a discussion of currently used\nalgorithms and the reconstruction of continuum physics from lattice results. We\nthen proceed to present some results for QCD, both at low energies and at high\ntemperatures, as well as for the electro-weak sector of the standard model."
    },
    {
        "anchor": "Series studies of the Potts model. I: The simple cubic Ising model: The finite lattice method of series expansion is generalised to the $q$-state\nPotts model on the simple cubic lattice.\n  It is found that the computational effort grows exponentially with the square\nof the number of series terms obtained, unlike two-dimensional lattices where\nthe computational requirements grow exponentially with the number of terms. For\nthe Ising ($q=2$) case we have extended low-temperature series for the\npartition functions, magnetisation and zero-field susceptibility to $u^{26}$\nfrom $u^{20}$. The high-temperature series for the zero-field partition\nfunction is extended from $v^{18}$ to $v^{22}$. Subsequent analysis gives\ncritical exponents in agreement with those from field theory.",
        "positive": "FINITE TEMPERATURE PHASE TRANSITION IN QCD WITH STRANGE QUARK: STUDY\n  WITH WILSON FERMIONS ON THE LATTICE: The effect of the strange quark in the finite temperature phase transition of\nQCD is studied on the lattice. Using the one-plaquette gauge action and the\nWilson quark action, the transition in the chiral limit is shown to be\ncontinuous for the case of degenerate two flavors, $N_F=2$, while it is of\nfirst order for $N_F \\geq 3$. For a more realistic case of massless up and down\nquarks and a light strange quark, $N_F=2+1$, clear two state signals are\nobserved both for $m_s \\simeq 150$ and 400 MeV. In contrast to a previous\nresult with staggered quarks, this suggests a first order transition in the\nreal world. In order to see the implication of these results to the continuum\nlimit, we started to study these issues using improved actions. First results\nusing a RG improved gauge action combined with the standard Wilson quark is\npresented for the case of $N_F=2$: With this action the finite temperature\ntransition is shown to be continuous in the chiral limit confirming the result\nof the standard action. Furthermore, not like the case of the standard action\nwhere lattice artifacts make the transition once very strong at intermediate\nvalues of the hopping parameter $K$ on $N_t=4$ and 6 lattices, a smooth\ncrossover is found for the improved action when we increase $1/K-1/K_c$, in\naccord with a naive expectation about the fate of second order chiral\ntransition at finite $m_q$."
    },
    {
        "anchor": "Chiral symmetry of QCD with twelve light flavors: We study QCD with twelve light flavors at intermediate values of the bare\nlattice coupling. We contrast the results for the order parameter with\ndifferent theoretical models motivated by the physics of the Goldstone phase\nand of the symmetric phase, and we perform a model independent analysis of the\nmeson spectrum inspired by universal properties of chiral symmetry. Our\nanalysis favors chiral symmetry restoration.",
        "positive": "Performance of several Lanczos eigensolvers with HISQ fermions: We investigate the state-of-the-art Lanczos eigensolvers available in the\nGrid and QUDA libraries. They include Implicitly Restarted Lanczos,\nThick-Restart Lanczos, and Block Lanczos. We measure and analyze their\nperformance for the Highly Improved Staggered Quark (HISQ) Dirac operator. We\nalso discuss optimization of Chebyshev acceleration."
    },
    {
        "anchor": "Theory of color confinement: state of the art: The existing evidence for dual superconductivity as mechanism of color\nconfinement is reviewed. We also discuss what is known on the dual excitations,\nwhich produce confinement by condensation, and what are the open problems",
        "positive": "Charmonium spectral functions from 2+1 flavour lattice QCD: Finite temperature charmonium spectral functions in the pseudoscalar and\nvector channels are studied in lattice QCD with 2+1 flavours of dynamical\nWilson quarks, on fine isotropic lattices (with a lattice spacing of 0.057 fm),\nwith a non-physical pion mass of $m_{\\pi} \\approx$ 545 MeV. The highest\ntemperature studied is approximately $1.4 T_c$. Up to this temperature no\nsignificant variation of the spectral function is seen in the pseudoscalar\nchannel. The vector channel shows some temperature dependence, which seems to\nbe consistent with a temperature dependent low frequency peak related to heavy\nquark transport, plus a temperature independent term at \\omega>0. These results\nare in accord with previous calculations using the quenched approximation."
    },
    {
        "anchor": "Analysis and Development of Stochastic Multigrid Methods in Lattice\n  Field Theory: We study the relation between the dynamical critical behavior and the\nkinematics of stochastic multigrid algorithms. The scale dependence of\nacceptance rates for nonlocal Metropolis updates is analyzed with the help of\nan approximation formula. A quantitative study of the kinematics of multigrid\nalgorithms in several interacting models is performed. We find that for a\ncritical model with Hamiltonian H(phi) absence of critical slowing down can\nonly be expected if the expansion of <H(phi+psi)> in terms of the shift psi\ncontains no relevant term (mass term). The predictions of this rule are\nverified in a multigrid Monte Carlo simulation of the Sine Gordon model in two\ndimensions. Our analysis can serve as a guideline for the development of new\nalgorithms: We propose a new multigrid method for nonabelian lattice gauge\ntheory, the time slice blocking. For SU(2) gauge fields in two dimensions,\ncritical slowing down is almost completely eliminated by this method, in\naccordance with the theoretical prediction. The generalization of the time\nslice blocking to SU(2) in four dimensions is investigated analytically and by\nnumerical simulations. Compared to two dimensions, the local disorder in the\nfour dimensional gauge field leads to kinematical problems.",
        "positive": "Towards fully bayesian analyses in Lattice QCD: We present a promising method to learn physical parameters from a bayesian\ninference, using modern tools to replace both our traditional fits and the way\nerrors are computed and propagated. A few models are built as illustrations for\na realistic case with Lattice QCD data, and appear to extract a lot of\ninformation with good stability. We discuss the evaluation of these models with\neither a fully bayesian approach or information criteria, as well as the\nmodel-building challenges which remain to be solved."
    },
    {
        "anchor": "Twisted lattice supersymmetry and applications to AdS/CFT: I review recent approaches to constructing supersymmetric lattice theories\nfocusing in particular on the concept of topological twisting. The latter\ntechnique is shown to expose a nilpotent, scalar supersymmetry which can be\nimplemented exactly in the lattice theory. Using these ideas a lattice action\nfor $\\mathcal{N}=4$ super Yang-Mills in four dimensions can be written down\nwhich is gauge invariant, free of fermion doublers and respects one out of a\ntotal of 16 continuum supersymmetries. It is shown how these exact symmetries\ntogether with the large point group symmetry of the lattice strongly constrain\nthe possible counterterms needed to renormalize the theory and hence determine\nhow much residual fine tuning will be needed to restore all supersymmetries in\nthe continuum limit. We report on progress to study these renormalization\neffects at one loop. We go on to give examples of applications of these\nsupersymmetric lattice theories to explore the connections between gauge\ntheories and gravity.",
        "positive": "Towards Lattice QCD Baryon Forces at the Physical Point: First Results: Lattice QCD calculations of baryon forces are performed for the first time\nwith (almost) physical quark masses. $N_f = 2+1$ dynamical clover fermion gauge\nconfigurations are generated at the lattice spacing of $a \\simeq 0.085$ fm on a\n$(96 a)^4 \\simeq (8.2 {\\rm fm})^4$ lattice with quark masses corresponding to\n$(m_\\pi, m_K) \\simeq (146, 525)$ MeV. Baryon forces are calculated using the\ntime-dependent HAL QCD method. In this report, we study $\\Xi\\Xi$ and $NN$\nsystems both in $^1S_0$ and $^3S_1$-$^3D_1$ channels, and the results for the\ncentral and tensor forces as well as phase shifts in the $\\Xi\\Xi$ $(^1S_0)$\nchannel are presented."
    },
    {
        "anchor": "Testing UV-filtered (\"fat-link\") clover fermions: We investigate filtered clover fermions, built from fat gauge links, both in\none-loop perturbation theory and in numerical simulations. We use a variety of\nfiltering recipes (APE, HYP, EXP, HEX), some of which are suitable for a HMC\nwith dynamical fermions. A generic filtering together with a (fat-link) clover\nterm yields fermions with much reduced chiral symmetry breaking.",
        "positive": "Lattice QCD simulations with light dynamical quarks: I report recent results from full QCD simulations by CP-PACS and JLQCD\ncollaborations."
    },
    {
        "anchor": "Dressed Wilson loops as dual condensates in response to magnetic and\n  electric fields: We introduce dressed Wilson loops as a novel confinement observable. It\nconsists of closed planar loops of arbitrary geometry but fixed area, and its\nexpectation values decay with the latter. The construction of dressed Wilson\nloops is based on chiral condensates in response to magnetic and electric\nfields, thus linking different physical concepts. We present results for\ngeneralized condensates and dressed Wilson loops on dynamical lattice\nconfigurations and confirm the agreement with conventional Wilson loops in the\nlimit of large probe mass. We comment on the renormalization of dressed Wilson\nloops.",
        "positive": "Nucleon and pion structure with lattice QCD simulations at physical\n  value of the pion mass: We present results on the nucleon scalar, axial and tensor charges as well as\non the momentum fraction, and the helicity and transversity moments. The pion\nmomentum fraction is also presented. The computation of these key observables\nis carried out using lattice QCD simulations at a physical value of the pion\nmass. The evaluation is based on gauge configurations generated with two\ndegenerate sea quarks of twisted mass fermions with a clover term. We\ninvestigate excited states contributions with the nucleon quantum numbers by\nanalyzing three sink-source time separations. We find that, for the scalar\ncharge, excited states contribute significantly and to a less degree to the\nnucleon momentum fraction and helicity moment. Our analysis yields a value for\nthe nucleon axial charge agrees with the experimental value and we predict a\nvalue of 1.027(62) in the $\\overline{\\text{MS}}$ scheme at 2 GeV for the\nisovector nucleon tensor charge directly at the physical point. The pion\nmomentum fraction is found to be $\\langle\nx\\rangle_{u-d}^{\\pi^\\pm}=0.214(15)(^{+12}_{-9})$ in the $\\overline{\\rm MS}$ at\n2 GeV."
    },
    {
        "anchor": "Solving Lattice QCD systems of equations using mixed precision solvers\n  on GPUs: Modern graphics hardware is designed for highly parallel numerical tasks and\npromises significant cost and performance benefits for many scientific\napplications. One such application is lattice quantum chromodyamics (lattice\nQCD), where the main computational challenge is to efficiently solve the\ndiscretized Dirac equation in the presence of an SU(3) gauge field. Using\nNVIDIA's CUDA platform we have implemented a Wilson-Dirac sparse matrix-vector\nproduct that performs at up to 40 Gflops, 135 Gflops and 212 Gflops for double,\nsingle and half precision respectively on NVIDIA's GeForce GTX 280 GPU. We have\ndeveloped a new mixed precision approach for Krylov solvers using reliable\nupdates which allows for full double precision accuracy while using only single\nor half precision arithmetic for the bulk of the computation. The resulting\nBiCGstab and CG solvers run in excess of 100 Gflops and, in terms of iterations\nuntil convergence, perform better than the usual defect-correction approach for\nmixed precision.",
        "positive": "Automated lattice perturbation theory: I review recent developments in automated lattice perturbation theory.\nStarting with an overview of lattice perturbation theory, I focus on the three\nautomation packages currently \"on the market\": HiPPy/HPsrc, Pastor and\nPhySyCAl. I highlight some recent applications of these methods, particularly\nin B physics. In the final section I briefly discuss the related, but distinct,\napproach of numerical stochastic perturbation theory."
    },
    {
        "anchor": "Logarithmic Corrections and Finite-Size Scaling in the Two-Dimensional\n  4-State Potts Model: We analyze the scaling and finite-size-scaling behavior of the\ntwo-dimensional 4-state Potts model. We find new multiplicative logarithmic\ncorrections for the susceptibility, in addition to the already known ones for\nthe specific heat. We also find additive logarithmic corrections to scaling,\nsome of which are universal. We have checked the theoretical predictions at\ncriticality and off criticality by means of high-precision Monte Carlo data.",
        "positive": "Gradient flow scale-setting with $N_f=2+1+1$ Wilson-clover twisted-mass\n  fermions: We present a determination of the gradient flow scales $w_0$, $\\sqrt{t_0}$\nand $t_0/w_0$ in isosymmetric QCD, making use of the gauge ensembles produced\nby the Extended Twisted Mass Collaboration (ETMC) with $N_f=2+1+1$ flavours of\nWilson-clover twisted-mass quarks including configurations close to the\nphysical point for all dynamical flavours. The simulations are carried out at\nthree values of the lattice spacing and the scale is set through the PDG value\nof the pion decay constant, yielding $w_0=0.17383(63)$ fm,\n$\\sqrt{t_0}=0.14436(61)$ fm and $t_0/w_0=0.11969(62)$ fm. Finally, fixing the\nkaon mass to its isosymmetric value, we determine the ratio of the kaon and\npion leptonic decay constants to be $f_K/f_{\\pi}=1.1995(44)$."
    },
    {
        "anchor": "QCD Level Density from Maximum Entropy Method: We propose a method to calculate the QCD level density directly from the\nthermodynamic quantities obtained by lattice QCD simulations with the use of\nthe maximum entropy method (MEM). Understanding QCD thermodynamics from QCD\nspectral properties has its own importance. Also it has a close connection to\nphenomenological analyses of the lattice data as well as experimental data on\nthe basis of hadronic resonances. Our feasibility study shows that the MEM can\nprovide a useful tool to study QCD level density.",
        "positive": "Numerical Study of $ K^0$--$\\bar{K}^0$ Mixing and $ B_K $: We have computed $ B_K $ with staggered fermions, using two different\nmethods: both in the one spin trace form and two spin trace form. Renormalized\nresults in both forms are in good agreement. The numerical simulations were\nperformed on a $ 16^3 \\times 40 $ lattice in full QCD with $ \\beta = 5.7 $. We\nalso tried an improved wall source method in order to select only the\npseudo-Goldstone bosons and compare the numerical results obtained with those\nfrom the conventional wall source method. We have studied $ B_K $ with a series\nof non-degenerate quark anti-quark pairs and saw no effect on $ B_K $, although\ndramatic effects in the chiral limit were seen on the individual terms making\nup $ B_K $."
    },
    {
        "anchor": "One-loop matching of the $CP$-odd three-gluon operator to the gradient\n  flow: The calculation of the neutron electric dipole moment within effective field\ntheories for physics beyond the Standard Model requires non-perturbative\nhadronic matrix elements of effective operators composed of quark and gluon\nfields. In order to use input from lattice computations, these matrix elements\nmust be translated from a scheme suitable for lattice QCD to the\nminimal-subtraction scheme used in the effective-field-theory framework. The\naccuracy goal in the context of the neutron electric dipole moment necessitates\nat least a one-loop matching calculation. Here, we provide the one-loop\nmatching coefficients for the $CP$-odd three-gluon operator between two\ndifferent minimally subtracted 't Hooft-Veltman schemes and the gradient flow.\nThis completes our program to obtain the one-loop gradient-flow matching\ncoefficients for all $CP$-violating and flavor-conserving operators in the\nlow-energy effective field theory up to dimension six.",
        "positive": "Heavy-light mesons in lattice HQET and QCD: We present a study of a combination of HQET and relativistic QCD to extract\nthe b-quark mass and the Bs-meson decay constant from lattice quenched\nsimulations. We start from a small volume, where one can directly simulate the\nb-quark, and compute the connection to a large volume, where finite size\neffects are negligible, through a finite size technique. The latter consists of\nsteps extrapolated to the continuum limit, where the b-region is reached\nthrough interpolations guided by the effective theory.\n  With the lattice spacing given in terms of the Sommer's scale r0 and the\nexperimental Bs and K masses, we get the final results for the renormalization\ngroup invariant mass Mb = 6.88(10) GeV, translating into mb(mb) = 4.42(6) GeV\nin the MSbar scheme, and fBs = 191(6) MeV for the decay constant.\n  A renormalization condition for the chromo-magnetic operator, responsible, at\nleading order in the heavy quark mass expansion of HQET, for the mass splitting\nbetween the pseudoscalar and the vector channel in mesonic heavy-light bound\nstates, is provided in terms of lattice correlations functions which well suits\na non-perturbative computation involving a large range of renormalization\nscales and no valence quarks.\n  The two-loop expression of the corresponding anomalous dimension in the\nSchroedinger functional (SF) scheme is computed starting from results in the\nliterature; it requires a one-loop calculation in the SF scheme with a\nnon-vanishing background field. The cutoff effects affecting the scale\nevolution of the renormalization factors are studied at one-loop order, and\nconfirmed by non-perturbative quenched computations to be negligible for the\nnumerical precision achievable at present."
    },
    {
        "anchor": "The basis of the physical Hilbert space of lattice gauge theories: Non-linear Fourier analysis on compact groups is used to construct an\northonormal basis of the physical (gauge invariant) Hilbert space of\nHamiltonian lattice gauge theories. In particular, the matrix elements of the\nHamiltonian operator involved are explicitly computed. Finally, some\napplications and possible developments of the formalism are discussed.",
        "positive": "On P-vortices and the Gribov problem: We study the possible connection between centre vortices and P-vortices in\nSU(2) gauge theory. After briefly recalling some essential properties of centre\nvortices we point out that there is no known a priori connection between the\ngauge dependent P-vortices and the gauge invariant centre vortices. We then\nshow by Monte Carlo simulations that the `centre projected physics' strongly\ndepends on the gauge copy from which the maximal centre gauge fixing is\nstarted. This reveals the presence of Gribov problems, and casts some doubts on\nthe physical meaning of P-vortices, and should be further investigated."
    },
    {
        "anchor": "Continuous Time Monte Carlo for Lattice QCD in the Strong Coupling Limit: We present results for lattice QCD in the limit of infinite gauge coupling,\nobtained from a worm-type Monte Carlo algorithm on a discrete spatial lattice\nbut with continuous Euclidean time. This is obtained by sending both the\nanisotropy parameter gamma^2 \\sim a/a_t and the number of time-slices N_\\tau to\ninfinity, keeping the ratio \\gamma^2/N_\\tau \\sim aT fixed. The obvious gain is\nthat no continuum extrapolation N_\\tau -> \\infty has to be carried out.\nMoreover, the algorithm is faster and the sign problem disappears. We compare\nour computations with those on discrete lattices. We determine the phase\ndiagram as a function of temperature and baryon chemical potential.",
        "positive": "Investigating the critical properties of beyond-QCD theories using Monte\n  Carlo Renormalization Group matching: Monte Carlo Renormalization Group (MCRG) methods were designed to study the\nnon-perturbative phase structure and critical behavior of statistical systems\nand quantum field theories. I adopt the 2-lattice matching method used\nextensively in the 1980's and show how it can be used to predict the existence\nof non-perturbative fixed points and their related critical exponents in many\nflavor SU(3) gauge theories. This work serves to test the method and I study\nrelatively well understood systems: the $N_f=0$, 4 and 16 flavor models. The\npure gauge and $N_f=4$ systems are confining and chirally broken and the MCRG\nmethod can predict their bare step scaling functions. Results for the $N_f=16$\nmodel indicate the existence of an infrared fixed point with nearly marginal\ngauge coupling. I present preliminary results for the scaling dimension of the\nmass at this new fixed point."
    },
    {
        "anchor": "Quark masses from quenched overlap fermions: We compute light and strange quark masses for quenched overlap fermions at\ntwo values of the gauge coupling. The renormalisation is done\nnon-perturbatively. We test the predictions of quenched chiral perturbation\ntheory for the quark mass dependence of the hadron spectrum and see evidence\nfor the existence of chiral logs.",
        "positive": "Interglueball potential in lattice SU(N) gauge theories: The dynamics of the glueballs is important in the context of the experimental\nsearch as well as for understanding the non-Abelian gauge theory. The glueballs\nof the dark $SU(N_c)$ Yang-Mills theory are also good candidates of dark\nmatter. In this proceedings contribution, we report on the result of the\nlattice calculation of the interglueball potential of the Yang-Mills theory\nwith the color numbers $N_c=2,3,4$, with a detailed inspection of the\nsystematics due to the discretization."
    },
    {
        "anchor": "Beauty Physics in Lattice Gauge Theory: We summarize the present status of lattice gauge theory computations of the\nleptonic decay constants $f_D$ and $f_B$. The various sources of systematic\nerrors are explained in a manner easily understood by the non--expert. The\nresults obtained by the different groups are then systematically compared. As a\nresult, we derive estimates for $f_D$ and $f_B$ in the quenched approximation\nthrough an appropriate combination of the data available from the different\ngroups. Since we account for a possible lattice spacing dependence, the final\nerrors are quite large. However, it is now well known how these uncertainties\ncan be reduced. For the decay constant of heavy--light pseudoscalar mesons with\nmasses of 1-2~GeV, an interesting comparison of a full QCD result with the\ncorresponding simulation in the quenched approximation can be done. Effects of\nsea quarks of mass $m_s$ are below the statistical accuracy of these\nsimulations. Related quantities, like $B$--parameters, the spectrum of\nbeauty--hadrons and the breaking of the QCD string are discussed briefly.",
        "positive": "Scaling functions of the three-dimensional $Z(2)$, $O(2)$ and $O(4)$\n  models and their finite size dependence in an external field: We analyze scaling functions in the $3$-$d$, $Z(2)$, $O(2)$ and $O(4)$\nuniversality classes and their finite size dependence using Monte Carlo\nsimulations of improved $\\phi^4$ models. Results for the scaling functions are\nfitted to the Widom-Griffiths form, using a parametrization also used in\nanalytic calculations. We find good agreement on the level of scaling functions\nand the location of maxima in the universal part of susceptibilities. We also\nfind that an earlier parametrization of the $O(4)$ scaling function, using 14\nparameters, is well reproduced when using the Widom-Griffiths form with only\nthree parameters. We furthermore show that finite size corrections to the\nscaling functions are distinctively different in the $Z(2)$ and $O(N)$\nuniversality classes and determine the volume dependence of the peak locations\nin order parameter and mixed susceptibilities."
    },
    {
        "anchor": "Computing Masses from Effective Transfer Matrices: We study the use of effective transfer matrices for the numerical computation\nof masses (or correlation lengths) in lattice spin models. The effective\ntransfer matrix has a strongly reduced number of components. Its definition is\nmotivated by a renormalization group transformation of the full model onto a\n1-dimensional spin model. The matrix elements of the effective transfer matrix\ncan be determined by Monte Carlo simulation. We show that the mass gap can be\nrecovered exactly from the spectrum of the effective transfer matrix. As a\nfirst step towards application we performed a Monte Carlo study for the\n2-dimensional Ising model. For the simulations in the broken phase we employed\na multimagnetical demon algorithm. The results for the tunnelling correlation\nlength are particularly encouraging.",
        "positive": "Meson-Meson Scattering in Lattice QED_2+1: Scattering phase shifts of a meson-meson system in staggered 3-dimensional\nlattice QED are computed. The main task of the simulation is to obtain a\ndiscrete set of two-body energy levels. These are extracted from a 4-point time\ncorrelation matrix and then used to obtain scattering phase shifts. The results\nfor the l=0 and l=2 partial waves are consistent with short- range repulsion\nand intermediate-range attraction of the residual meson- meson interaction."
    },
    {
        "anchor": "Isocliny in spinor space and Wilson fermions: We show that Clifford algebras are closely related to the study of isoclinic\nsubspaces of spinor spaces and, consequently, to the Hurwitz-Radon matrix\nproblem. Isocliny angles are introduced to parametrize gamma matrices, i.e.,\nmatrix representations of the generators of finite-dimensional Clifford\nalgebras C(m,n). Restricting the consideration to the Clifford algebra C(4,0),\nthis parametrization is then applied to the study of Dirac traces occurring in\nEuclidean lattice quantum field theory within the hopping parameter expansion\nfor Wilson fermions.",
        "positive": "Determination of $\\overline{m}_b/\\overline{m}_c$ and $\\overline{m}_b$\n  from $n_f=4$ lattice QCD$+$QED: We extend HPQCD's earlier $n_f=4$ lattice-QCD analysis of the ratio of\n$\\overline{\\mathrm{MSB}}$ masses of the $b$ and $c$ quark to include results\nfrom finer lattices (down to 0.03fm) and a new calculation of QED contributions\nto the mass ratio. We find that\n$\\overline{m}_b(\\mu)/\\overline{m}_c(\\mu)=4.586(12)$ at renormalization scale\n$\\mu=3$\\,GeV. This result is nonperturbative. Combining it with HPQCD's recent\nlattice QCD$+$QED determination of $\\overline{m}_c(3\\mathrm{GeV})$ gives a new\nvalue for the $b$-quark mass: $\\overline{m}_b(3\\mathrm{GeV}) = 4.513(26)$GeV.\nThe $b$-mass corresponds to $\\overline{m}_b(\\overline{m}_b, n_f=5) =\n4.202(21)$GeV. These results are the first based on simulations that include\nQED."
    },
    {
        "anchor": "'Bs --> Ds l nu' near zero recoil in and beyond the Standard Model: We compute the normalization of the form factor entering the Bs --> Ds l nu\ndecay amplitude by using numerical simulations of QCD on the lattice. From our\nstudy with Nf=2 dynamical light quarks, and by employing the maximally twisted\nWilson quark action, we obtain in the continuum limit G(1) = 1.052(46). We also\ncompute the scalar and tensor form factors in the region near zero recoil and\nfind f0(t0)/f+(t0)=0.77(2), fT(t0,mb)/f+(t0)=1.08(7), for t0=11.5 GeV^2. These\nlatter results are useful for searching the effects of physics beyond the\nStandard Model in Bs --> Ds l nu decays. Our results for the similar form\nfactors relevant to the non-strange case indicate that the method employed here\ncan be used to achieve the precision determination of the B --> D l nu decay\namplitude as well.",
        "positive": "Stabilizing complex Langevin for real-time gauge theories with an\n  anisotropic kernel: The complex Langevin (CL) method is a promising approach to overcome the sign\nproblem that occurs in real-time formulations of quantum field theories. Using\nthe Schwinger-Keldysh formalism, we study SU($N_c$) gauge theories with CL. We\nobserve that current stabilization techniques are insufficient to obtain\ncorrect results. Therefore, we revise the discretization of the CL equations on\ncomplex time contours, find a time reflection symmetric formulation and\nintroduce a novel anisotropic kernel that enables CL simulations on discretized\ncomplex time paths. Applying it to SU(2) Yang-Mills theory in 3+1 dimensions,\nwe obtain unprecedentedly stable results that we validate using additional\nobservables and that can be systematically improved. For the first time, we are\nable to simulate non-Abelian gauge theory on time contours whose real-time\nextent exceeds its inverse temperature. Thus, our approach may pave the way\ntowards an ab-initio real-time framework of QCD in and out of equilibrium with\na potentially large impact on the phenomenology of heavy-ion collisions."
    },
    {
        "anchor": "Vacuum energy of two-dimensional N=(2,2) super Yang-Mills theory: We measure the vacuum energy of two-dimensional N=(2,2) super Yang-Mills\ntheory using lattice simulation. The obtained vacuum energy density is\nE_0=0.09(9)(+10-8) g^2, where the first error is the systematic and the second\nis the statistical one, measured in the dimensionful gauge coupling g which\ngoverns the scale of the system. The result is consistent with unbroken\nsupersymmetry, although we cannot exclude a possible very small non-zero vacuum\nenergy.",
        "positive": "Topological charge using cooling and the gradient flow: The equivalence of cooling to the gradient flow when the cooling step $n_c$\nand the continuous flow step of gradient flow $\\tau$ are matched is generalized\nto gauge actions that include rectangular terms. By expanding the link\nvariables up to subleading terms in perturbation theory, we relate $n_c$ and\n$\\tau$ and show that the results for the topological charge become equivalent\nwhen rescaling $\\tau \\simeq n_c/({3-15 c_1})$ where $c_1$ is the Symanzik\ncoefficient multiplying the rectangular term. We, subsequently, apply cooling\nand the gradient flow using the Wilson, the Symanzik tree-level improved and\nthe Iwasaki gauge actions to configurations produced with $N_f=2+1+1$ twisted\nmass fermions. We compute the topological charge, its distribution and the\ncorrelators between cooling and gradient flow at three values of the lattice\nspacing demonstrating that the perturbative rescaling $\\tau \\simeq n_c/({3-15\nc_1})$ leads to equivalent results."
    },
    {
        "anchor": "Two dimensional SU(N) x SU(N) chiral models on the lattice: Lattice $SU(N)\\times SU(N)$ chiral models are analyzed by strong and weak\ncoupling expansions and by numerical simulations. $12^{th}$ order strong\ncoupling series for the free and internal energy are obtained for all $N\\geq\n6$. Three loop contributions to the internal energy and to the lattice\n$\\beta$-function are evaluated for all $N$ and non-universal corrections to the\nasymptotic $\\Lambda$ parameter are computed in the ``temperature'' and the\n``energy'' scheme. Numerical simulations confirm a faster approach to\nasymptopia of the energy scheme. A phenomenological correlation between the\npeak in the specific heat and the dip of the $\\beta$-function is observed.\nTests of scaling are performed for various physical quantities, finding\nsubstantial scaling at $\\xi \\gtrsim 2$. In particular, at $N=6$ three different\nmass ratios are determined numerically and found in agreement, within\nstatistical errors of about 1\\%, with the theoretical predictions from the\nexact S-matrix theory.",
        "positive": "The sign problem and Abelian lattice duality: For a large class of Abelian lattice models with sign problems, including the\ncase of non-zero chemical potential, duality maps models with complex actions\ninto dual models with real actions. For extended regions of parameter space,\ncalculable for each model, duality resolves the sign problem for both analytic\nmethods and computer simulations. Explicit duality relations are given for\nmodels for spin and gauge models based on Z(N) and U(1) symmetry groups. The\ndual forms are generalizations of the Z(N) chiral clock model and the lattice\nFrenkel-Kontorova model, respectively. From these equivalences, rich sets of\nspatially-modulated phases are found in the strong-coupling region of the\noriginal models."
    },
    {
        "anchor": "Zemach radius of the proton from lattice QCD: We present the first lattice-QCD result for the Zemach radius of the proton.\nOur calculation includes both quark-connected and -disconnected diagrams and\nassesses all sources of systematic uncertainties arising from excited-state\ncontributions, finite-volume effects and the continuum extrapolation. At the\nphysical point, we obtain $r_Z^p = ( 1.013 \\pm 0.010\\ (\\mathrm{stat}) \\pm\n0.012\\ (\\mathrm{syst}) )~\\mathrm{fm}$, which suggests a small value of the\nZemach radius, but is compatible with most of the experimental studies.",
        "positive": "Short-recurrence Krylov subspace methods for the overlap Dirac operator\n  at nonzero chemical potential: The overlap operator in lattice QCD requires the computation of the sign\nfunction of a matrix, which is non-Hermitian in the presence of a quark\nchemical potential. In previous work we introduced an Arnoldi-based Krylov\nsubspace approximation, which uses long recurrences. Even after the deflation\nof critical eigenvalues, the low efficiency of the method restricts its\napplication to small lattices. Here we propose new short-recurrence methods\nwhich strongly enhance the efficiency of the computational method. Using\nrational approximations to the sign function we introduce two variants, based\non the restarted Arnoldi process and on the two-sided Lanczos method,\nrespectively, which become very efficient when combined with multishift\nsolvers. Alternatively, in the variant based on the two-sided Lanczos method\nthe sign function can be evaluated directly. We present numerical results which\ncompare the efficiencies of a restarted Arnoldi-based method and the direct\ntwo-sided Lanczos approximation for various lattice sizes. We also show that\nour new methods gain substantially when combined with deflation."
    },
    {
        "anchor": "Remarks on the Gauge Dependence of the RI/MOM Renormalization Procedure: The RI/MOM non-perturbative renormalization scheme is studied on the lattice\nin SU(3) quenched QCD with Wilson fermions. The gauge dependence of some\nfermion bilinear renormalization constants is discussed by comparing data which\nhave been gauge-fixed in two different realizations of the Landau gauge and in\na generic covariant gauge. The very good agreement between the various sets of\nresults and the theory indicates that the numerical uncertainty induced by the\nlattice gauge-fixing procedure is moderate and below the statistical errors.",
        "positive": "Temporal meson correlators at finite temperature on quenched anisotropic\n  lattice: We study charmonium correlators at finite temperature in quenched anisotropic\nlattice QCD. The smearing technique is applied to enhance the low energy part\nof the correlator. We use two analysis procedures: the maximum entropy method\nfor extraction of the spectral function without assuming specific form, as an\nestimate of the shape of spectral function, and the $\\chi^2$ fit assuming\ntypical forms as quantitative evaluation of the parameters associated to the\nforms. We find that at $T\\simeq 0.9T_c$ the ground state peak has almost the\nsame mass as at T=0 and almost vanishing width. At $T\\simeq 1.1T_c$, our result\nsuggests that the correlator still has nontrivial peak structure at almost the\nsame position as below $T_c$ with finite width."
    },
    {
        "anchor": "Electrical conductivity of the quark-gluon plasma across the\n  deconfinement transition: A lattice calculation is presented for the electrical conductivity of the QCD\nplasma with 2+1 dynamical flavours at nonzero temperature. We employ the\nconserved lattice current on anisotropic lattices using a tadpole-improved\nclover action and study the behaviour of the conductivity over a wide range of\ntemperatures, both below and above the deconfining transition. The conductivity\nis extracted from a spectral-function analysis using the Maximal Entropy Method\nand a discussion of its systematics is provided.",
        "positive": "Pion Distribution Amplitudes in the Continuum Limit: We present a lattice-QCD calculation of the pion distribution amplitudes\nusing large-momentum effective theory (LaMET). Our calculation is carried out\nusing five ensembles with 2+1+1 flavors of highly improved staggered quarks\n(HISQ), generated by MILC collaboration, at 310 MeV and 220 MeV pion mass with\n0.06, 0.09, 0.12 and 0.15 fm lattice spacings. We use clover fermion action for\nthe valence quarks and tune the quark mass to match the lightest light and\nstrange masses in the sea. The resulting lattice matrix elements are\nnonperturbatively renormalized in regularization-independent\nmomentum-subtraction (RI/MOM) scheme and extrapolated to the continuum. We\ncompare different approaches to extract the x-dependence of the pion\ndistribution amplitudes."
    },
    {
        "anchor": "$Z_6$ symmetry, electroweak transition, and magnetic monopoles at high\n  temperature: We consider the lattice realization of the Standard Model with an additional\n$Z_6$ symmetry. Numerical simulations were performed on the asymmetric lattice,\nwhich corresponds to the finite temperature theory. Our choice of parameters\ncorresponds to large Higgs masses ($M_H > 90$ Gev). The phase diagram was\ninvestigated and has been found to be different from that of the usual lattice\nrealization of the Standard Model. It has been found, that the\nconfinement-deconfinement phase transition lines for the SU(2) and SU(3) fields\ncoincide. The transition line between Higgs and symmetric deconfinement parts\nof the phase diagram and the confinement-deconfinement transition line meet in\na triple point. The transition between Higgs and symmetric parts of the phase\ndiagram corresponds to the finite temperature electroweak transition/crossover.\nWe see for the first time evidence that Nambu monopoles are condensed at\n$T>T_c$ while at $T<T_c$ their condensate vanishes.",
        "positive": "Isovector Charges of the Nucleon from 2+1+1-flavor Lattice QCD: We present high statistics results for the isovector charges $g^{u-d}_A$,\n$g^{u-d}_S$ and $g^{u-d}_T$ of the nucleon. Calculations were carried out on\neleven ensembles of gauge configurations generated by the MILC collaboration\nusing highly improved staggered quarks (HISQ) action with 2+1+1 dynamical\nflavors. These ensembles span four lattice spacings $a \\approx$ 0.06, 0.09,\n0.12 and 0.15 fm and light-quark masses corresponding to $M_\\pi \\approx$ 135,\n225 and 315 MeV. Excited-state contamination in the nucleon 3-point correlation\nfunctions is controlled by including up to three-states in the spectral\ndecomposition. Remaining systematic uncertainties associated with lattice\ndiscretization, lattice volume and light-quark masses are controlled using a\nsimultaneous fit in these three variables. Our final estimates of the isovector\ncharges in the $\\overline{\\text{MS}}$ scheme at 2 GeV are $g_A^{u-d} =\n1.218(25)(30)$, $g_S^{u-d} = 1.022(80)(60) $ and $g_T^{u-d} = 0.989(32)(10)$.\nThe first error includes statistical and all systematic uncertainties except\nthat due to the extrapolation ansatz, which is given by the second error\nestimate. We provide a detailed comparison with the recent result of $g_A^{u-d}\n= 1.271(13)$ by the CalLat collaboration and argue that our error estimate is\nmore realistic. Combining our estimate for $g_S^{u-d}$ with the difference of\nlight quarks masses $(m_d-m_u)^{\\rm QCD}=2.572(66)$ MeV given by the\nMILC/Fermilab/TUMQCD collaboration for 2+1+1-flavor theory, we obtain\n$(M_N-M_P)^{\\rm QCD} = 2.63(27)$ MeV. We update the low-energy constraints on\nnovel scalar and tensor interactions, $\\epsilon_{S}$ and $\\epsilon_{T}$, at the\nTeV scale by combining our new estimates for $g^{u-d}_S$ and $g^{u-d}_T$ with\nprecision low-energy nuclear experiments, and find them comparable to those\nfrom the ATLAS and the CMS experiments at the LHC."
    },
    {
        "anchor": "The QCD equation of state to $\\mathcal{O}(\u03bc_B^4)$: We present results from an ongoing calculation of the QCD equation of state\nat finite baryon chemical potential $\\mu_B$. We use the method of Taylor\nexpansions to circumvent the sign problem and calculate the expansion\ncoefficients to sixth order using HISQ fermions. We work at two lattice\nspacings, namely $N_\\tau=6$ and 8 and, though we do not take the continuum\nlimit, demonstrate that cutoff effects remain under control. We also use our\nresults to construct an equation of state along the freeze-out curve. Using our\nsixth-order results as a cross-check, we demonstrate that our fourth-order\nequation of state is suitable for the modeling of dense matter created in heavy\nion collisions with center-of-mass energies down to $s_{NN}^{1/2}\\sim20$ GeV.",
        "positive": "First Glimpse into the Kaon Gluon Parton Distribution Using Lattice QCD: In this work, we present the first results on the gluon parton distribution\nof the kaon from lattice quantum chromodynamics. We carry out the lattice\ncalculation at pion mass around 310~MeV and two lattice spacings, 0.15 and\n0.12~fm, using $2+1+1$-flavor HISQ ensembles generated by MILC Collaboration.\nThe kaon correlators are calculated using clover fermions and momentum-smearing\nsources with maximum boost momentum around 2~GeV and high statistics (up to\n324,000 measurements). We study the dependence of the resulting reduced\nIoffe-time pseudo-distributions at multiple boost momenta and lattice spacings.\nWe then extract the kaon gluon distribution function in the\n$\\overline{\\text{MS}}$ scheme at $\\mu = 2$~GeV, neglecting the mixing between\nthe gluon and singlet-quark sectors. Our results at the smaller lattice spacing\nare consistent with phenomenological determinations."
    },
    {
        "anchor": "Can complex Langevin dynamics evade the sign problem?: I answer the question in the title for the relativistic Bose gas at finite\nchemical potential using numerical lattice simulations, complemented with\nanalytical understanding.",
        "positive": "Hadron spectrum of QCD with one quark flavor: The latest results of an ongoing project for the lattice simulation of QCD\nwith a single quark flavor are presented. The Symanzik tree-level-improved\nWilson action is adopted in the gauge sector and the (unimproved) Wilson action\nfor the fermion. Results from new simulations with one step of Stout-smearing\n(rho=0.15) in the fermion action are discussed. The one-flavor theory is\nsimulated by a polynomial hybrid Monte Carlo algorithm (PHMC) at beta=4.0\ncorresponding to a = 0.13fm, on 16^3x32 and 24^3x48 lattices; the box-size is L\n= 2.1fm and L = 3.1fm, respectively. At the lightest simulated quark mass the\n(partially quenched) pion mass is ~300 MeV. The masses of the lightest bound\nstates are computed, including the flavor singlet scalar and pseudoscalar\nmesons sigma_s and eta_s, the scalar glueball 0^++, and the Delta^++ baryon.\nRelics of SUSY in the mass spectrum, expected from a large N_c orientifold\nequivalence with the N=1 supersymmetric Yang-Mills theory, are discussed."
    },
    {
        "anchor": "Monte Carlo overrelaxation for SU(N) gauge theories: The standard approach to Monte Carlo simulations of SU(N) Yang-Mills theories\nupdates successive SU(2) subgroups of each SU(N) link. We follow up on an old\nproposal of Creutz, to perform overrelaxation in the full SU(N) group instead,\nand show that it is more efficient.",
        "positive": "Landau gauge ghost and gluon propagators in SU(2) lattice gauge theory:\n  Gribov ambiguity revisited: We reinvestigate the problem of Gribov ambiguities within the Landau (or\nLorentz) gauge for the ghost and gluon propagators in pure SU(2) lattice gauge\ntheory. We make use of the full symmetry group of the action taking into\naccount {\\it large}, i.e. non-periodic $\\mathbb{Z}(2)$ gauge transformations\nleaving lattice plaquettes invariant. Enlarging in this way the gauge orbits\nfor any given gauge field configuration the Landau gauge can be fixed at higher\nlocal extrema of the gauge functional in comparison with standard\n(overrelaxation) techniques. This has a clearly visible effect not only for the\nghost propagator at small momenta but also for the gluon propagator, in\ncontrast to the common belief."
    },
    {
        "anchor": "Attractive $N$-$\u03c6$ Interaction and Two-Pion Tail from Lattice QCD\n  near Physical Point: First results on the interaction between the $\\phi$-meson and the nucleon\n($N$) are presented based on the ($2+1$)-flavor lattice QCD simulations with\nnearly physical quark masses. Using the HAL QCD method, the spacetime\ncorrelation of the $N$-$\\phi$ system in the spin 3/2 channel is converted into\nthe $N$-$\\phi$ scattering phase shift through the interaction potential. The\n$N$-$\\phi$ potential appears to be a combination of a short-range attractive\ncore and a long-range attractive tail. The latter is found to be consistent\nwith the two-pion exchange (TPE) obtained from the interaction between a\ncolor-dipole and the nucleon. The resultant scattering length and effective\nrange for $m_{\\pi}=$ 146.4 MeV are $ a^{(3/2)}_0=-1.43(23)_{\\rm\nstat.}\\left(^{+36}_{-06}\\right)_{\\rm syst.} {\\rm fm}$ and $ r^{(3/2)}_{\\rm\neff}=2.36(10)_{\\rm stat.}\\left(^{+02}_{-48}\\right)_{\\rm syst.} {\\rm fm}$,\nrespectively. The magnitude of the scattering length is shown to have\nnontrivial dependence of $m_{\\pi}$ and is sensitive to the existence of the\nlong-range tail from TPE.",
        "positive": "Nuclear Transition in the Strong Coupling Limit: Lattice QCD at finite baryon chemical potential has the infamous sign problem\nwhich hinders Monte Carlo simulations. This can be remedied by a dual\nrepresentation that makes the sign problem mild. In the strong coupling limit,\nthe dual formulation with staggered quarks is well established. We have used\nthis formulation to study the quark mass dependence of the baryon mass and the\nnuclear transition. This allows us to quantify the nuclear interaction. We have\nalso compared our Monte Carlo results with mean field predictions."
    },
    {
        "anchor": "Phases of a strongly coupled four-fermion theory: We present ongoing investigations of a four-dimensional lattice field theory\nwith four massless reduced staggered fermions coupled through an\nSU(4)-invariant four-fermion interaction. As in previous studies of\nfour-fermion and Higgs--Yukawa models with different lattice fermion\ndiscretizations, we observe a strong-coupling phase in which the system\ndevelops a mass gap without breaking any lattice symmetry. This symmetric\nstrong-coupling phase is separated from the symmetric weak-coupling phase by a\nnarrow region of four-fermi coupling in which the system exhibits long-range\ncorrelations.",
        "positive": "Static Quark Potential and the Renormalized Anisotropy on Tadpole\n  Improved Anisotropic Lattices: Static quark potential is studied using a tadpole improved gauge lattice\naction. The scale is set using the potential for a wide range of bare\nparameters.\n  The renormalized anisotropy of the lattice is also measured."
    },
    {
        "anchor": "Y(4260) on the lattice: We investigate the mass spectra of closed-charm mesons with $ J^{PC} = 1^{--}\n$, for hybrid charmonium, molecules, and diquark-antidiquark operators, in\nquenched lattice QCD with exact chiral symmetry. For two lattice volumes $ 24^3\n\\times 48 $ and $ 20^3 \\times 40 $, each of 100 gauge configurations generated\nwith single-plaquette action at $ \\beta = 6.1 $, we compute point-to-point\nquark propagators and measure the time-correlation functions of these exotic\nmeson operators. For the molecular operator $\n\\{(\\qbar\\gamma_5\\gamma_i\\c)(\\cbar\\gamma_5\\q)-\n  (\\cbar\\gamma_5\\gamma_i\\q)(\\qbar\\gamma_5\\c) \\} $, it detects a resonance with\nmass around $ 4238 \\pm 31 $ MeV, which is naturally identified with $ Y(4260)\n$. Further, for any molecular and diquark-antidiquark operator, it detects\nheavier exotic charmed mesons, with quark content $ (\\c\\s\\cbar\\sbar) $ around $\n4450 \\pm 100 $ MeV, and $ (\\c\\c\\cbar\\cbar) $ around $ 6400 \\pm 50 $ MeV.",
        "positive": "Monopoles and deconfinement transition in SU(2) lattice gauge theory: We investigate SU(2) lattice gauge theory in four dimensions in the maximally\nabelian projection. Studying the effects on different lattice sizes we show\nthat the deconfinement transition of the fields and the percolation transition\nof the monopole currents in the three space dimensions are precisely related.\nTo arrive properly at this result the uses of a mathematically sound\ncharacterization of the occurring networks of monopole currents and of an\nappropriate method of gauge fixing turn out to be crucial. In addition we\ninvestigate detailed features of the monopole structure in time direction."
    },
    {
        "anchor": "The U(1) phase transition on toroidal and spherical lattices: We have studied the properties of the phase transition in the U(1) compact\npure gauge model paying special atention to the influence of the topology of\nthe boundary conditions. From the behavior of the energy cumulants and the\nobservation of an effective \\nu -> 1/d on toroidal and spherical lattices, we\nconclude that the transition is first order.",
        "positive": "The low-lying baryon spectrum with two dynamical twisted mass fermions: The masses of the low lying baryons are evaluated using two degenerate\nflavors of twisted mass sea quarks corresponding to pseudo scalar masses in the\nrange of about 270-500 MeV. The strange valence quark mass is tuned to\nreproduce the mass of the kaon in the physical limit. The tree-level Symanzik\nimproved gauge action is employed. We use lattices of spatial size 2.1 fm and\n2.7 fm at two values of the lattice spacing with $r_0/a=5.22(2)$ and\n$r_0/a=6.61(3)$. We check for both finite volume and cut-off effects on the\nbaryon masses. We performed a detailed study of the chiral extrapolation of the\noctet and decuplet masses using SU(2) $\\chi$PT. The lattice spacings determined\nusing the nucleon mass at the physical point are consistent with the values\nextracted using the pion decay constant. We examine the issue of isospin\nsymmetry breaking for the octet and decuplet baryons and its dependence on the\nlattice spacing. We show that in the continuum limit isospin breaking is\nconsistent with zero, as expected. The baryon masses that we find after taking\nthe continuum limit and extrapolating to the physical limit are in good\nagreement with experiment."
    },
    {
        "anchor": "Comment on \"Relation between scattering amplitude and Bethe-Salpeter\n  wave function in quantum field theory\": We invalidate the arguments given in [T.Yamazaki and Y.Kuramashi, Phys. Rev.\nD96, 114511 (2017)] over the HAL QCD method for hadron-hadron interactions on\nthe lattice. We also pose questions on the practical usefulness of the method\nproposed in this reference.",
        "positive": "Thermodynamical Observables in a Finite Temperature Window from the\n  Monte Carlo Hamiltonian: The Monte Carlo (MC) Hamiltonian is a new stochastic method to solve\nmany-body problems. The MC Hamiltonian represents an effective Hamiltonian in a\nfinite energy window. We construct it from the classical action via Monte Carlo\nwith importance sampling. The MC Hamiltonian yields the energy spectrum and\ncorresponding wave functions in a low energy window. This allows to compute\nthermodynamical observables in a low temperature window. We show the working of\nthe MC Hamiltonian by an example from lattice field theory (Klein-Gordon\nmodel)."
    },
    {
        "anchor": "Magnetic monopole dominance for the Wilson loops in higher\n  representations: The dual superconductor picture is one of the most promising scenarios for\nquark confinement. To investigate this picture in a gauge-invariant manner, we\nhave proposed a new formulation of Yang-Mills theory, named the decomposition\nmethod, on the lattice. The so-called restricted field obtained from the\ngauge-covariant decomposition plays the dominant role in quark confinement. It\nhas been known by preceding works that the restricted-field dominance is not\nobserved for the Wilson loop in higher representations if the restricted part\nof the Wilson loop is obtained by adopting the Abelian projection or the field\ndecomposition naively in the same way as done in the fundamental\nrepresentation. Recently, through the non-Abelian Stokes theorem (NAST) for the\nWilson loop operator, we have proposed suitable gauge-invariant operators\nconstructed from the restricted field to reproduce the correct behavior of the\noriginal Wilson loop averages for higher representations. We have demonstrated\nthe numerical evidence for the restricted-field dominance in the string\ntension.\n  In this talk, we focus on the magnetic monopole. According to this picture,\nmagnetic monopoles causing the dual superconductivity are the dominant degrees\nof freedom responsible for confinement. With the help of the NAST, we define\nthe magnetic monopole and the string tension extracted from the\nmagnetic-monopole part of the Wilson loop in a gauge-invariant manner. We will\nfurther perform lattice simulations to measure the static potential for quarks\nin higher representations using the proposed operators and examine the magnetic\nmonopole dominance in the string tension, which means that the string tension\nextracted from the magnetic-monopole part of the Wilson loop reproduces the\nproper string tension obtained from the original Wilson loop.",
        "positive": "Universal behaviour of the SU(2) running coupling constant in the\n  continuum limit: We present data from the ALPHA Collaboration about lattice calculation of\nSU(2) pure--gauge running coupling constant, obtained with two different\ndefinitions of the coupling itself, which show universality of the continuum\nlimit and clarify the applicability of renormalized perturbation theory."
    },
    {
        "anchor": "Clock model interpolation and symmetry breaking in O(2) models: The $q$-state clock model is a classical spin model that corresponds to the\nIsing model when $q=2$ and to the $XY$ model when $q\\to\\infty$. The integer-$q$\nclock model has been studied extensively and has been shown to have a single\nphase transition when $q=2$,$3$,$4$ and two phase transitions when $q>4$.We\ndefine an extended $q$-state clock model that reduces to the ordinary $q$-state\nclock model when $q$ is an integer and otherwise is a continuous interpolation\nof the clock model to noninteger $q$. We investigate this class of clock models\nin 2D using Monte Carlo (MC) and tensor renormalization group (TRG) methods,\nand we find that the model with noninteger $q$ has a crossover and a\nsecond-order phase transition. We also define an extended-$O(2)$ model (with a\nparameter $\\gamma$) that reduces to the $XY$ model when $\\gamma=0$ and to the\nextended $q$-state clock model when $\\gamma\\to\\infty$, and we begin to outline\nthe phase diagram of this model. These models with noninteger $q$ serve as a\ntestbed to study symmetry breaking in situations corresponding to quantum\nsimulators where experimental parameters can be tuned continuously.",
        "positive": "A variational method for spectral functions: The Generalized Eigenvalue Problem (GEVP) has been used extensively in the\npast in order to reliably extract energy levels from time-dependent Euclidean\ncorrelators calculated in Lattice QCD. We propose a formulation of the GEVP in\nfrequency space. Our approach consists of applying the model-independent\nBackus-Gilbert method to a set of Euclidean two-point functions with common\nquantum numbers. A GEVP analysis in frequency space is then applied to a matrix\nof estimators that allows us, among other things, to obtain particular linear\ncombinations of the initial set of operators that optimally overlap to\ndifferent local regions in frequency. We apply this method to lattice data from\nNRQCD. This approach can be interesting both for vacuum physics as well as for\nfinite-temperature problems."
    },
    {
        "anchor": "$B\\to K$ and $D\\to K$ form factors from fully relativistic lattice QCD: We present the result of lattice QCD calculation of the scalar, vector and\ntensor form factors for the $B\\to K\\ell^+\\ell^-$ decay, across the full\nphysical range of momentum transfer. We use the highly improved staggered quark\n(HISQ) formalism for all valence quarks on eight ensembles of gluon field\nconfigurations generated by the MILC collaboration. These include four flavours\nof HISQ quarks in the sea, with three ensembles having the light $u/d$ quarks\nat physical masses. In the first fully relativistic calculation of these form\nfactors, we use the heavy-HISQ method. This allows us to determine the form\nfactors as a function of heavy quark mass from the $c$ to the $b$, and so we\nalso obtain new results for the $D\\to K$ tensor form factor. The advantage of\nthe relativistic formalism is that we can match the lattice weak currents to\ntheir continuum counterparts much more accurately than in previous\ncalculations; our scalar and vector currents are renormalised fully\nnonperturbatively and we use a well-matched intermediate momentum-subtraction\nscheme for our tensor current. Our scalar and vector $B\\to K$ form factors have\nuncertainties of less than 4% across the entire physical $q^2$ range and the\nuncertainty in our tensor form factor is less than 7%. Our heavy-HISQ method\nallows us to map out the dependence on heavy-quark mass of the form factors and\nwe can also see the impact of changing spectator quark mass by comparing to\nearlier HPQCD results for the same quark weak transition but for heavier\nmesons.",
        "positive": "Zb tetraquark channel from lattice QCD and Born-Oppenheimer\n  approximation: Two $Z_b$ hadrons with exotic quark structure $\\bar bb\\bar du$ were\ndiscovered by Belle experiment. We present a lattice QCD study of the $\\bar\nbb\\bar du$ system in the approximation of static $b$ quarks, where the total\nspin of heavy quarks is fixed to one. The energies of eigenstates are\ndetermined as a function of the separation $r$ between $b$ and $\\bar b$. The\nlower eigenstates are related to a bottomonium and a pion. The eigenstate\ndominated by $B\\bar B^*$ has energy significantly below $m_B+m_{B^*}$, which\npoints to a sizable attraction for small $r$. The attractive potential $V(r)$\nbetween $B$ and $\\bar B^*$ is extracted assuming that this eigenstate is\nrelated exclusively to $B\\bar B^*$. The Schr\\\"odinger equation for $B\\bar B^*$\nwithin the extracted potential leads to one bound state below $B\\bar B^*$\nthreshold, whose mass depends on the parametrization of the lattice potential.\nFor certain parametrizations, the bound state is very close to the $B\\bar B^*$\nthreshold and renders a narrow peak in the $B\\bar B^*$ rate above threshold -\nthese features could be related to $Z_b(10610)$ in the experiment."
    },
    {
        "anchor": "Towards a precise lattice determination of the leading hadronic\n  contribution to (g-2)_mu: We report on our computation of the leading hadronic contribution to the\nanomalous magnetic moment of the muon using two dynamical flavours of\nnon-perturbatively O(a) improved Wilson fermions. The strange quark is\nintroduced in the quenched approximation. Partially twisted boundary conditions\nare applied to improve the momentum resolution in the relevant integral. Our\nresults, obtained at three different values of the lattice spacing, allow for a\npreliminary study of discretization effects. We explore a wide range of lattice\nvolumes, namely 2 fm < L < 3 fm, with pion masses from 600 to 280 MeV and\ndiscuss different chiral extrapolations to the physical point. We observe a\nnon-trivial dependence of a_mu(HLO) on m_pi especially for small pion masses.\nThe final result, a_mu(HLO)=618(64)*10^(-10), is obtained by considering only\nthe quark connected contribution to the vacuum polarization. We present a\ndetailed analysis of systematic errors and discuss how they can be reduced in\nfuture simulations.",
        "positive": "First moments of the nucleon generalized parton distributions from\n  lattice QCD: We report on our lattice calculations of the nucleon's generalized parton\ndistributions (GPDs), concentrating on their first moments for the case of\nN_f=2. Due to recent progress on the numerical side we are able to present\nresults for the generalized form factors at pion masses as low as 260 MeV. We\nperform a fit to one-loop covariant baryon chiral perturbation theory with\nencouraging results."
    },
    {
        "anchor": "A fast minimal residual solver for overlap fermions: Computing quark propagators with overlap fermions requires the solution of a\nshifted unitary linear system. Jagels and Reichel have shown that for such\nsystems it is possible to construct a minimal residual algorithm by short\nrecurrences. The J\\\"ulich-Wuppertal group have found this algorithm to be the\nfastest among overlap solvers. In this paper we present a three-term recurrence\nfor the Arnoldi unitary process. Using the new recurrence we construct a\nminimal residual solver which is the fastest among all Krylov subspace\nalgorithms considered so far for the overlap inversion.",
        "positive": "On the spectrum of mesons in quenched $Sp(2N)$ gauge theories: We report the findings of our extensive study of the spectra of flavoured\nmesons in lattice gauge theories with symplectic gauge group and fermion matter\ncontent treated in the quenched approximation. For the $Sp(4)$, $Sp(6)$, and\n$Sp(8)$ gauge groups, the (Dirac) fermions transform in either the fundamental,\nor the 2-index, antisymmetric or symmetric, representations. This study sets\nthe stage for future precision calculations with dynamical fermions in the low\nmass region of lattice parameter space. Our results have potential\nphenomenological applications ranging from composite Higgs models, to top\n(partial) compositeness, to dark matter models with composite, strong-coupling\ndynamical origin. Having adopted the Wilson flow as a scale-setting procedure,\nwe apply Wilson chiral perturbation theory to extract the continuum and\nmassless limits for the observables of interest. The resulting measurements are\nused to perform a simplified extrapolation to the large-$N$ limit, hence\ndrawing a preliminary connection with gauge theories with unitary groups. We\nconclude with a brief discussion of the Weinberg sum rules."
    },
    {
        "anchor": "QCD phase transition with two flavors of Wilson quarks using a RG\n  improved action: The finite temperature QCD phase transition is studied on the lattice with\ndegenerate two flavors of Wilson quarks. Motivated by reported strange\nbehaviors with the standard action on lattices with the temporal extention\n$N_t=4$ and 6, a renormalization group improved gauge action is applied. On an\n$N_t=4$ lattice, the strange behaviors observed with the standard action are\nremoved with our improved action. The finite temperature transition is\ncontinuous in the chiral limit and it becomes quite smooth in all observables\nwe studied when we increase the quark mass by increasing $\\beta$ along the\ncrossover line.",
        "positive": "Light dynamical fermions on the lattice: toward the chiral regime of QCD: Algorithmic and technical progress achieved over the last few years makes QCD\nsimulations with light dynamical quarks much faster than before. As a result\nlattices with pions as light as 250--300 MeV can be simulated with the present\ngeneration of computers. I review recent conceptual and numerical progress in\nthis field, with particular emphasis on results obtained and difficulties\nencountered in simulations with significantly smaller quark masses with respect\nto previous computations. I also attempt to compare physical results for pion\nmasses and decay constants available to date in the two-flavour theory with\nexpectations from chiral perturbation theory."
    },
    {
        "anchor": "Overlap quark propagator near the physical pion mass: The Landau-gauge quark propagator is calculated using overlap fermions on\n2+1-flavour dynamical fermion gauge fields from the PACS-CS collaboration with\npion mass $m_\\pi \\sim 156\\text{ MeV}$ and spatial volume $\\sim (3 \\text{\nfm})^3.$ The observed features of the mass and renormalisation functions are\ndiscussed, including a comparison with recent results using\n$\\mathcal{O}(a)$-improved Wilson fermions on 2-flavour dynamical gauge fields.",
        "positive": "Numerical study of Yang-Mills classical solutions on the twisted torus: We use the lattice cooling method to investigate the structure of some gauge\nfixed SU(2) Yang-Mills classical solutions of the euclidean equations of motion\nwhich are defined in the 3-torus with symmetric twisted boundary conditions."
    },
    {
        "anchor": "An Exact Algorithm for Any-flavor Lattice QCD with Kogut-Susskind\n  Fermion: We propose an exact simulation algorithm for lattice QCD with dynamical\nKogut-Susskind fermion in which the N_f-flavor fermion operator is defined as\nthe N_f/4-th root of the Kogut-Susskind (KS) fermion operator. The algorithm is\nan extension of the Polynomial Hybrid Monte Carlo (PHMC) algorithm to KS\nfermions. The fractional power of the KS fermion operator is approximated with\na Hermitian Chebyshev polynomial, with which we can construct an algorithm for\nany number of flavors. The error which arises from the approximation is\ncorrected by the Kennedy-Kuti noisy Metropolis test. Numerical simulations are\nperformed for the two-flavor case for several lattice parameters in order to\nconfirm the validity and the practical feasibility of the algorithm. In\nparticular tests on a 16^4 lattice with a quark mass corresponding to\nm_{PS}/m_V ~ 0.68 are successfully accomplished. We conclude that our algorithm\nprovides an attractive exact method for dynamical QCD simulations with KS\nfermions.",
        "positive": "The scalar, vector and tensor form factors for the pion and kaon from\n  lattice QCD: We present a calculation of the scalar, vector, and tensor form factors for\nthe pion and kaon in lattice QCD. We use an ensemble of two degenerate light, a\nstrange and a charm quark ($N_f=2+1+1$) of maximally twisted mass fermions with\nclover improvement. The corresponding pion and kaon masses are about 265 MeV\nand 530 MeV, respectively. The calculation is done in both rest and boosted\nframes obtaining data for four-vector momentum transfer squared up to\n$-q^2=2.5$ GeV$^2$ for the pion and 3 GeV$^2$ for the kaon. The excited-states\neffects are studied by analyzing six values of the source-sink time separation\nfor the rest frame ($1.12-2.23$ fm) and for four values for the boosted frame\n($1.12-1.67$ fm). The lattice data are renormalized non-perturbatively and the\nresults for the scheme- and scale-dependent scalar and tensor form factors are\npresented in the $\\overline{\\rm MS}$ scheme at a scale of 2 GeV. We apply\ndifferent parametrizations to describe $q^2$-dependence of the form factors to\nextract the scalar, vector, and tensor radii, as well as the tensor anomalous\nmagnetic moment. We compare the pion and kaon form factors to study SU(3)\nflavor symmetry breaking effects. By combining the data for the vector and\ntensor form factors we also obtain the lowest moment of the densities of\ntransversely polarized quarks in the impact parameter space. Finally, we give\nan estimate for the average transverse shift in the $y$ direction for polarized\nquarks in the $x$ direction."
    },
    {
        "anchor": "Anomalous transport with overlap fermions: Anomalous correlators of vector and axial currents which enter the Kubo\nformulae for the chiral magnetic and the chiral separation conductivities are\nexplicitly calculated for free overlap fermions on the lattice. The results are\nconfronted with continuum calculations in the finite-temperature\nregularization, and a subtle point of such regularization for chiral magnetic\nconductivity related to the correct counting of the chiral states is\nhighlighted. In agreement with some previous claims in the literature, we find\nthat in a lattice regularization which respects gauge invariance, the chiral\nmagnetic conductivity vanishes. We point out that the relation of anomalous\ntransport coefficients to axial anomaly is nontrivial due to the\nnon-commutativity of their infrared limit and the Taylor expansion in baryon or\nchiral chemical potential. In particular, we argue that the vector and axial\nWard identities fix the asymptotic behavior of anomalous current-current\ncorrelators in the limit of large momenta. Basing on the work of Knecht et al.\non the perturbative non-renormalization of the transverse part of the\ncorrelator of two vector and one axial currents, we demonstrate that the\nrelation of the anomalous vector-vector correlator to axial anomaly holds\nperturbatively in massless QCD but might be subject to non-perturbative\ncorrections. Finally, we identify kinematical regimes in which the anomalous\ntransport coefficients can be extracted from lattice measurements.",
        "positive": "A Determination of Interface Free Energies: We determine the interface free energy $F_{o.d.}$ between disordered and\nordered phases in the q=10 and q=20 2-d Potts models using the results of\nmulticanonical Monte Carlo simulations on $L^2$ lattices, and suitable finite\nvolume estimators. Our results, when extrapolated to the infinite volume limit,\nagree to high precision with recent analytical calculations. At the transition\npoint $\\beta_t$ the probability distribution function of the energy exhibits\ntwo maxima. Their locations have $1/L^2$ corrections, in contradiction with\nclaims of $1/L$ behavior made in the literature. Our data show a flat region\ninbetween the two maxima which characterizes two domain configurations."
    },
    {
        "anchor": "A nucleon in a tiny box: We use Chiral Perturbation Theory to compute the nucleon mass-shift due to\nfinite volume and temperature effects. Our results are valid up to\nnext-to-leading order in the \"\\eps-regime\" (mL ~ m\\beta << 1) as well as in the\n\"p-regime\" (mL ~ m\\beta >> 1). Based on the two leading orders, we discuss the\nconvergence of the expansion as a function of the lattice size and quark\nmasses. This result can be used to extrapolate lattice results obtained from\nlattice sizes smaller than the pion cloud, avoiding the numerical simulation of\nphysics under theoretical control. An extraction of the low-energy coefficient\nc_3 of the chiral Lagrangean from lattice simulations at small volumes and a\n``magic'' ratio \\beta=1.22262 L might be possible.",
        "positive": "Continuum limit of SU(3) $\\mathcal{N}=1$ supersymmetric Yang-Mills\n  theory and supersymmetric gauge theories on the lattice: We summarize our investigations of several aspects of $\\mathcal{N}=1$\nsupersymmetric Yang-Mills (SYM) theory. We present our final results for SU(3)\n$\\mathcal{N}=1$ SYM simulated with Wilson fermions. We also discuss the first\ntest of the simulations of the theory with overlap gluinos. Finally, we present\nsome recent progresses concerning the phase structure of the compactified\ntheory on $R^3\\times S^1$."
    },
    {
        "anchor": "High Precision Simulation Techniques for Lattice Field Theory: An overview is given over the recently developed and now widely used Monte\nCarlo algorithms with reduced or eliminated critical slowing down. The basic\ntechniques are overrelaxation, cluster algorithms and multigrid methods. With\nthese tools one is able to probe much closer than before the universal\ncontinuum behavior of field theories on the lattice.",
        "positive": "Supersymmetric Yang-Mills Theories from Domain Wall Fermions: We present work in progress on employing domain wall fermions to simulate N=1\nsupersymmetric Yang-Mills theories on the lattice in d=4 and d=3 dimensions.\nThe geometrical nature of domain wall fermions gives simple insights into how\nto construct these theories. We also discuss the obstacles associated with\nsimulating the N=2 theory in d=4."
    },
    {
        "anchor": "Third-order perturbative lattice and complex Langevin analyses of the\n  finite-temperature equation of state of non-relativistic fermions in one\n  dimension: We analyze the pressure and density equations of state of unpolarized\nnon-relativistic fermions at finite temperature in one spatial dimension. For\nattractively interacting regimes, we perform a third-order lattice perturbation\ntheory calculation, assess its convergence properties by comparing with hybrid\nMonte Carlo results (there is no sign problem in this regime), and demonstrate\nagreement with real Langevin calculations. For repulsive interactions, we\npresent lattice perturbation theory results as well as complex Langevin\ncalculations, with a modified action to prevent uncontrolled excursions in the\ncomplex plane. Although perturbation theory is a common tool, our\nimplementation of it is unconventional; we use a Hubbard-Stratonovich\ntransformation to decouple the system and automate the application of Wick's\ntheorem, thus generating the diagrammatic expansion, including symmetry\nfactors, at any desired order. We also present an efficient technique to tackle\nnested Matsubara frequency sums without relying on contour integration, which\nis independent of dimension and applies to both relativistic and\nnon-relativistic systems, as well as all energy-independent interactions. We\nfind exceptional agreement between perturbative and non-perturbative results at\nweak couplings, and furnish predictions based on complex Langevin at strong\ncouplings. We additionally present perturbative calculations of up to the\nfifth-order virial coefficient for repulsive and attractive couplings. Both the\nlattice perturbation theory and complex Langevin formalisms can easily be\nextended to a variety of situations including polarized systems, bosons, and\nhigher dimension.",
        "positive": "Spectrum Results with Kogut-Susskind Quarks: I summarize recent developments in spectrum calculations using Kogut-Susskind\nquarks. Theoretical developments include one-loop computations with improved\nactions. I present some recent simulation results, mostly from a MILC\ncollaboration project using three flavors. Effects of dynamical quarks are\nclearly seen in the isovector 0++ meson propagator and in the mass ratio ``J''."
    },
    {
        "anchor": "One-loop perturbative coupling of $A$ and $A_\\star$ through the chiral\n  overlap operator: We study the one-loop effective action defined by the chiral overlap operator\nin the four-dimensional lattice formulation of chiral gauge theories by\nGrabowska and Kaplan. In the tree-level continuum limit, the left-handed\ncomponent of the fermion is coupled only to the original gauge field~$A$, while\nthe right-handed one is coupled only to~$A_\\star$, which is given by the\ngradient flow of~$A$ with infinite flow time. In this paper, we show that the\ncontinuum limit of the one-loop effective action contains local interaction\nterms between $A$ and~$A_\\star$, which do not generally vanish even if the\ngauge representation of the fermion is anomaly free. We argue that the presence\nof such interaction terms can be regarded as undesired gauge symmetry-breaking\neffects in the formulation.",
        "positive": "Monte Carlo studies of antiferromagnetic spin models in three dimensions: We study several antiferromagnetic formulations of the O(3) spin model in\nthree dimensions by means of Monte Carlo simulations. We discuss about the\nvacua properties and analyze the phase transitions. Using Finite Size Scaling\nanalysis we conclude that all phase transitions found are of first order"
    },
    {
        "anchor": "The Renormalized Trajectory of the O(N) Non-linear Sigma Model: The renormalized trajectory (RT) is determined from two different Monte Carlo\nrenormalization group techniques with $\\delta$-function block spin\ntransformation in the multi-dimensional coupling parameter space of the\ntwo-dimensional non-linear sigma model with O(3) symmetry. At a correlation\nlength $\\xi \\approx 3$-$5$, the RT is shown to break away from the straight\nline of the fixed point trajectory (FPT) which is orthogonal to the critical\nsurface and originates from the ultraviolet fixed point (UVFP). The large $N$\ncalculation of the RT is also presented in the coupling parameter space of the\nmost general bilinear Hamiltonian. The RT in the large $N$ approximation\nexhibits a similar shape with the sharp break occurring at a somewhat smaller\ncorrelation length.",
        "positive": "Flavour physics and Lattice QCD: averages of lattice inputs for the\n  Unitarity Triangle Analysis: We review recent results of Lattice QCD calculations relevant for flavour\nphysics. We discuss in particular the hadronic parameters entering the\namplitudes of K0-K0bar, D0-D0bar and B0-B0bar mixing, the B- and D-meson decay\nconstants and the form factors controlling B-meson semileptonic decays. On the\nbasis of these lattice results, which are extensively collected in the paper,\nwe also derive our averages of the relevant hadronic parameters."
    },
    {
        "anchor": "The $\u0394_{mix}$ parameter in the overlap on domain-wall mixed action: A direct calculation of the mixed-action parameter $\\Delta_{mix}$ with\nvalence overlap fermions on a domain-wall fermion sea is presented. The\ncalculation is performed on four ensembles of the 2+1-flavor domain-wall gauge\nconfigurations: $24^3 \\times 64$ ($a m_l= 0.005$, $a=0.114\\fm$) and $32^3\n\\times 64$ ($a m_l = 0.004, 0.006, 0.008$, $a=0.085\\fm$). For pion masses close\nto $300\\MeV$ we find \\hbox{$\\Delta_{mix}=0.030(6)\\GeV^4$} at $a=0.114\\fm$ and\n$\\Delta_{mix}=0.033(12)\\GeV^4$ at $a=0.085\\fm$. The results are quite\nindependent of the lattice spacing and they are significantly smaller than the\nresults for valence domain-wall fermions on Asqtad sea or those of valence\noverlap fermions on clover sea. Combining the results extracted from these two\nensembles, we get $\\Delta_{mix}=0.030(6)(5)\\GeV^4$, where the first error is\nstatistical and the second is the systematic error associated with the fitting\nmethod.",
        "positive": "Light-cone PDFs from Lattice QCD: Using the approach proposed a few years ago by X. Ji, it has become feasible\nto extract parton distribution functions (PDFs) from lattice QCD, a task\nthought to be extremely difficult before Ji's proposal. In this talk, we\ndiscuss this approach, in particular different systematic effects that need to\nbe controlled to ultimately have precise determinations of PDFs. Special\nattention is paid to the analysis of excited states. We emphasize that it is\ncrucial to control excited states contamination and we show an analysis thereof\nfor our lattice data, used to calculate quasi-PDFs and finally light-cone PDFs\nin the second part of this proceeding (C. Alexandrou et al., Quasi-PDFs from\nTwisted mass fermions at the physical point)."
    },
    {
        "anchor": "The Wilson Dirac Spectrum for QCD with Dynamical Quarks: All microscopic correlation functions of the spectrum of the Hermitian Wilson\nDirac operator with any number of flavors with equal masses are computed. In\nparticular, we give explicit results for the spectral density in the physical\ncase with two light quark flavors. The results include the leading effect in\nthe discretization error and are given for fixed index of the Wilson Dirac\noperator. They have been obtained starting from chiral Lagrangians for the\ngenerating function of the Dirac spectrum. Microscopic correlation functions of\nthe real eigenvalues of the Wilson Dirac operator are computed following the\nsame approach.",
        "positive": "Critical point in the QCD phase diagram for extremely strong background\n  magnetic fields: Lattice simulations have demonstrated that a background (electro)magnetic\nfield reduces the chiral/deconfinement transition temperature of quantum\nchromodynamics for eB < 1 GeV^2. On the level of observables, this reduction\nmanifests itself in an enhancement of the Polyakov loop and in a suppression of\nthe light quark condensates (inverse magnetic catalysis) in the transition\nregion. In this paper, we report on lattice simulations of 1+1+1-flavor QCD at\nan unprecedentedly high value of the magnetic field eB = 3.25 GeV^2. Based on\nthe behavior of various observables, it is shown that even at this extremely\nstrong field, inverse magnetic catalysis prevails and the transition, albeit\nbecoming sharper, remains an analytic crossover. In addition, we develop an\nalgorithm to directly simulate the asymptotically strong magnetic field limit\nof QCD. We find strong evidence for a first-order deconfinement phase\ntransition in this limiting theory, implying the presence of a critical point\nin the QCD phase diagram. Based on the available lattice data, we estimate the\nlocation of the critical point."
    },
    {
        "anchor": "Infrared fixed point and anomalous dimensions in a composite Higgs model: We use lattice simulations and the continuous renormalization-group method,\nbased on the gradient flow, to study a candidate theory of composite Higgs and\na partially composite top. The model is an SU(4) gauge theory with four Dirac\nfermions in each of the fundamental and two-index antisymmetric\nrepresentations. We find that the theory has an infrared fixed point at $g^2\n\\simeq 15.5$ in the gradient flow scheme. The mass anomalous dimension of each\nrepresentation is large at the fixed point. On the other hand, the anomalous\ndimensions of top-partner operators do not exceed 0.5 at the fixed point. This\nmay not be large enough for a phenomenologically successful model of partial\ncompositeness.",
        "positive": "Gauge Theory Couplings on Anisotropic Lattices: The advantage of simulating lattice field theory with quantum computers is\nhamstrung by the limited resources that induce large errors from finite volume\nand sizable lattice spacings. Previous work has shown how classical simulations\nnear the Hamiltonian limit can be used for setting the lattice spacings in\nreal-time through analytical continuation, thereby reducing errors in quantum\nsimulations. In this work, we derive perturbative relations between bare and\nrenormalized quantities in Euclidean spacetime at any anisotropy factor -- the\nratio of spatial to temporal lattice spacings -- and in any spatial dimension\nfor $U(N)$ and $SU(N)$. This reduces the required classical preprocessing for\nquantum simulations. We find less than $10\\%$ discrepancy between our\nperturbative results and those from existing nonperturbative determinations of\nthe anisotropy for $SU(2)$ and $U(1)$ gauge theories. For the discrete groups\n$\\mathbb{Z}_{10}$, $\\mathbb{Z}_{100}$ and $\\mathbb{BI}$, we perform lattice\nMonte Carlo simulations to extract anisotropy factors and observe similar\nagreement with our perturbative results."
    },
    {
        "anchor": "The two-dimensional 4-state Potts model in a magnetic field: We present a solution of the non-linear renormalization group equations\nleading to the dominant and subdominant singular behaviours of physical\nquantities (free energy density, correlation length, internal energy, specific\nheat, magnetization, susceptibility and magnetocaloric coefficient) at the\ncritical temperature in a non- vanishing magnetic field. The solutions i) lead\nto exact cancellation of logarithmic corrections in universal amplitude ratios\nand ii) prove recently proposed relations among logarithmic exponents.",
        "positive": "The Poincare Group of Discrete Minkowskian Space-Time: The lattice of integral points of 4-dimensional Minkowski space, together\nwith the inherited indefinite distance function, is considered as a model for\ndiscrete space-time. The Lorentz and Poincare groups of this discrete\nspace-time are identified as subgroups of the corresponding Lie groups. The\nlattice Lorentz group has irreducible projective (including linear)\nrepresentations which are restrictions of (all) finite-dimensional irreducible\nprojective representations of the Lorentz Lie group and hence can be used to\ndescribe all integral and half-odd-integral helicity. The (4-torus) momentum\nspace has a well-defined ``light cone'' of null points and there are orbits of\nthe lattice Lorentz group lying entirely in the torus light cone and having the\nlattice euclidean group of the plane as little group. Wigner's method for the\nPoincare Lie group can then be adapted to show, in the first instance, that the\nlattice Poincare group has unitary representations describing lattice free\nfields of zero mass and an arbitrary Lorentz helicity, in particular chiral\nfermions. There are no representations with a nonzero invariant mass."
    },
    {
        "anchor": "Introduction to Lattice Gaugefixing and Effective Quark and Gluon Masses: This talk was presented to a non-lattice audience at the June, 1992 Paris\nWorkshop on QCD Vacuum Structure. We report on the status of quark and gluon\npropagators in quenched, gaugefixed lattice QCD. In Landau gauge we find that\nthe effective quark mass in the chiral limit is $M_q \\sim 350(40)MeV$. Quark\nand gluon propagators, the slope of the quark dispersion relation, and\neffective masses all appear to depend on gauge. A link-chain picture of lattice\ngaugefixing in the color $N\\to\\infty$ and strong coupling limit, where the\nsystem becomes almost solvable, supports the gauge variance of these numerical\nresults. Subscribers will be given one Postscript file, the Figure included.\nLatex and Axis versions available from KY at kyee@rouge.phys.lsu.edu on\nrequest.",
        "positive": "Two-colour Lattice QCD with dynamical fermions at non-zero density\n  versus Matrix Models: We provide first evidence that Matrix Models describe the low lying complex\nDirac eigenvalues in a theory with dynamical fermions at non-zero density.\nLattice data for gauge group SU(2) with staggered fermions are compared to\ndetailed analytical results from Matrix Models in the corresponding symmetry\nclass, the complex chiral Symplectic Ensemble. They confirm the predicted\ndependence on chemical potential, quark mass and volume."
    },
    {
        "anchor": "Properties of quark gluon plasma from lattice calculations: I discuss lattice QCD calculations of the properties of strongly interacting\nmatter at finite temperature, including the determination of the transition\ntemperature Tc, equation of state, different static screening lengths and\nquarkonium spectral functions. The lattice data suggest that at temperatures\nabove 2Tc many properties of the quark gluon plasma can be understood using\nweak coupling approach, although non-perturbative effects due to static\nmagnetic fields are significant in some quantities.",
        "positive": "Dynamical Restoration of Z_N Symmetry in SU(N)+Higgs Theories: We study the Z_N symmetry in SU(N)+Higgs theories with the Higgs field in the\nfundamental representation. The distributions of the Polyakov loop show that\nthe Z_N symmetry is explicitly broken in the Higgs phase. On the other hand,\ninside the Higgs symmetric phase the Polyakov loop distributions and other\nphysical observables exhibit the Z_N symmetry. This effective restoration of\nthe Z_N symmetry changes the nature of the confinement-deconfinenement\ntransition. We argue that the Z_N symmetry will lead to time independent\ntopological defect solutions in the Higgs symmetric deconfined phase which will\nplay important role at high temperatures."
    },
    {
        "anchor": "Higgs boson mass bounds in the presence of a heavy fourth quark family: We present Higgs boson mass bounds in a lattice regularization allowing thus\nfor non-perturbative investigations. In particular, we employ a lattice\nmodified chiral invariant Higgs-Yukawa model using the overlap operator. We\nshow results for the upper and lower Higgs boson mass bounds in the presence of\na heavy mass-degenerate quark doublet with masses ranging up to 700 GeV. We\nperform infinite volume extrapolations in most cases, and examine several\nvalues of the lattice cutoff. Furthermore, we argue that the lower Higgs boson\nmass bound is stable with respect to the addition of higher dimensional\noperators to the scalar field potential. Our results have severe consequences\nfor the phenomenology of a fourth generation of quarks if a light Higgs boson\nis discovered at the LHC.",
        "positive": "Putting centre dominance under the microscope: We make various short points on the phenomenon of centre dominance in SU(2).\nThe Z(2) dominance seen in Wilson loops is related to the loop distribution and\nto half-odd-integer representations of the group. The distributions also make\nit clear that, in this picture, the requirement of vortices for confinement is\nessentially trivial. We confirm that the same effect appears in the positive\nplaquette model. The simple random vortex picture is shown to give a\nsubstantial fraction of the string tension."
    },
    {
        "anchor": "Towards the QCD equation of state at the physical point using Wilson\n  fermion: We study the (2+1)-flavor QCD at nonzero temperatures using nonperturbatively\nimproved Wilson quarks of the physical masses by the fixed scale approach. We\nperform physical point simulations at finite temperatures with the coupling\nparameters which were adopted by the PACS-CS Collaboration in their studies\nusing the reweighting technique. Zero temperature values are obtained on the\nPACS-CS configurations which are open to the public on the ILDG/JLDG. Finite\ntemperature configurations are generated with the RHMC algorithm. The lattice\nsizes are $32^3 \\times N_t$ with $N_t=14$, 13, $\\cdots$, 4 which correspond to\n$T \\approx 160$--550 MeV. We present results of some basic observables at these\ntemperatures and the status of our calculation of the equation of state.",
        "positive": "Equivariance and generalization in neural networks: The crucial role played by the underlying symmetries of high energy physics\nand lattice field theories calls for the implementation of such symmetries in\nthe neural network architectures that are applied to the physical system under\nconsideration. In these proceedings, we focus on the consequences of\nincorporating translational equivariance among the network properties,\nparticularly in terms of performance and generalization. The benefits of\nequivariant networks are exemplified by studying a complex scalar field theory,\non which various regression and classification tasks are examined. For a\nmeaningful comparison, promising equivariant and non-equivariant architectures\nare identified by means of a systematic search. The results indicate that in\nmost of the tasks our best equivariant architectures can perform and generalize\nsignificantly better than their non-equivariant counterparts, which applies not\nonly to physical parameters beyond those represented in the training set, but\nalso to different lattice sizes."
    },
    {
        "anchor": "Static-static-light-light tetraquarks in lattice QCD: I report on a lattice computation of the energy of a system of two light\nquarks and two static antiquarks as a function of the separation of the static\nantiquarks. In terms of hadrons such a system corresponds to a pair of B mesons\nand its energy to the hadronic potential. I present selected results for\ndifferent isospin, spin and parity combinations of the individual B mesons\nmainly focusing on those channels relevant to determine, whether two B mesons\nmay form a bound tetraquark state.",
        "positive": "Instantons or Monopoles? Dyons: Non-abelian gauge theories can be cast into abelian gauge theories with\nmonopoles. We ask what becomes of the instantons after abelian projection.\nInstantons are found to consist of closed dyon loops. It is shown that the\nelectric charge of the dyons is quantized. The implication of this result for\nthe dynamics of the Yang-Mills vacuum is briefly discussed."
    },
    {
        "anchor": "$K \\to \u03c0\u03c0$ Decays with Domain Wall Fermions: Towards Physical\n  Results: We are using domain wall fermions to study $K \\to \\pi \\pi$ matrix elements by\nmeasuring $K \\to \\pi$ and $K \\to 0$ matrix elements on the lattice and\nemploying chiral perturbation theory to relate these to the desired physical\nresult. The residual chiral symmetry breaking of domain wall fermions with a\nfinite extent in the fifth dimension impacts these measurements. Using the\nWard-Takahashi identities, we investigate residual chiral symmetry breaking\neffects for divergent quantities and study pathologies of the quenched\napproximation for small quark mass. We then discuss the $\\Delta S = 1$ operator\n$O_2$, where chiral symmetry is vital for the subtraction of unphysical\neffects.",
        "positive": "SU(3) deconfining phase transition with finite volume corrections due to\n  a confined exterior: Using the geometry of a double-layered torus we investigate the deconfining\nphase transition of pure SU(3) lattice gauge theory by Markov chain Monte Carlo\nsimulations. In one layer, called \"outside\", the temperature is set below the\ndeconfining temperature and in the other, called \"inside\", it is iterated to a\npseudo-transition temperature. Lattice sizes are chosen in a range suggested by\nthe physical volumes achieved in relativistic heavy ion collisions and both\ntemperatures are kept close enough to stay in the SU(3) scaling region.\nProperties of the transition are studied as function of the volume for three\noutside temperatures. When compared with infinite volume extrapolations, small\nvolume corrections of the deconfining temperature and width become competitive\nwith those found by including quarks. Effective finite size scaling exponents\nof the specific and Polyakov loop susceptibilities are also calculated."
    },
    {
        "anchor": "Electromagnetic and spin polarisabilities in lattice QCD: We discuss the extraction of the electromagnetic and spin polarisabilities of\nnucleons from lattice QCD. We show that the external field method can be used\nto measure all the electromagnetic and spin polarisabilities including those of\ncharged particles. We then turn to the extrapolations required to connect such\ncalculations to experiment in the context of finite volume chiral perturbation\ntheory. We derive results relevant for lattice simulations of QCD,\npartially-quenched QCD and quenched QCD. Our results for the polarisabilities\nshow a strong dependence on the lattice volume and quark masses, typically\ndiffering from the infinite volume limit by ~10% for current lattice volumes\nand quark masses.",
        "positive": "Triviality of $\u03c6^4_4$ in the broken phase revisited: We define a finite size renormalization scheme for $\\phi^4$ theory which in\nthe thermodynamic limit reduces to the standard scheme used in the broken\nphase. We use it to re-investigate the question of triviality for the four\ndimensional infinite bare coupling (Ising) limit. The relevant observables all\nrely on two-point functions and are very suitable for a precise estimation with\nthe worm algorithm. This contribution updates an earlier publication by\nanalysing a much larger dataset."
    },
    {
        "anchor": "The Microscopic Representation of Complex Macroscopic Phenomena\n  (Critical Slowing Down - A Blessing in Disguise): Many complex systems are representable as macroscopic set of elements which\ninteract by simple rules. The complex macroscopically relevant phenomena are\nthen the result of the generic emergence of a space-time multi-scale dynamics.\nCritical Slowing Down labels the emerging global features and describes their\ncomplex collective evolution. This paradigm is quite universal and extends to a\nvery wide range of systems and disciplines.",
        "positive": "Estimation of the photon production rate using imaginary momentum\n  correlators: The thermal photon emission rate is determined by the spatially transverse,\nin-medium spectral function of the electromagnetic current. Accessing the\nspectral function using Euclidean data is, however, a challenging problem due\nto the ill-posed nature of inverting the Laplace transform. In this\ncontribution, we present the first results on implementing the proposal of\ndirectly computing the analytic continuation of the retarded correlator at\nfixed, vanishing virtuality of the photon via the calculation of the\nappropriate Euclidean correlator at imaginary spatial momentum. We employ two\ndynamical O(a)-improved Wilson fermions at a temperature of 250 MeV."
    },
    {
        "anchor": "Numerical results of two-dimensional N=(2,2) super Yang-Mills theory: We report the results of a numerical simulation of a lattice formulation of\nthe two-dimensional N=(2,2) super Yang-Mills theory proposed by Suzuki and\nTaniguchi. We measure the 1-point functions and 2-point functions. The scenario\nis that only tuning of the scalar mass to a specific value gives a\nsupersymmetric continuum limit. Our results are consistent with this scenario\nalthough conclusive results on the restoration of supersymmetry have not been\nobtained.",
        "positive": "The Strangeness and Charmness of Nucleon from Overlap Fermions: The calculation of the strangeness and charmness of the nucleon is presented\nwith overlap fermion action on 2+1 flavor domain wall fermion configurations.\nWe adopt stochastic grid sources and the low mode substitution technique to\nimprove the signals of nucleon correlation functions and the loops. The\ncalculation is done on a $24^3\\times 64$ lattice with $m_l=0.005$, $m_h=0.04$,\nand $a^{-1}=1.73\\,{\\rm GeV}$. We find $ f_{T_{s}} = 0.048(15)$ and $f_{T_{c}} =\n0.029(43)$."
    },
    {
        "anchor": "On the Structure of the Yang-Mills Vacuum: In this talk I will discuss the current picture of color confinement. In\nparticular, I will show how it can be tested microscopically. It is stressed\nthat the color magnetic monopoles in this picture are dyons. Furthermore, the\nrole of instantons is illuminated.",
        "positive": "Axial coupling constant of the nucleon for two flavours of dynamical\n  quarks in finite and infinite volume: We present data for the axial coupling constant g_A of the nucleon obtained\nin lattice QCD with two degenerate flavours of dynamical non-perturbatively\nimproved Wilson quarks. The renormalisation is also performed\nnon-perturbatively. For the analysis we give a chiral extrapolation formula for\ng_A based on the small scale expansion scheme of chiral effective field theory\nfor two degenerate quark flavours. Applying this formalism in a finite volume\nwe derive a formula that allows us to extrapolate our data simultaneously to\nthe infinite volume and to the chiral limit. Using the additional lattice data\nin finite volume we are able to determine the axial coupling of the nucleon in\nthe chiral limit without imposing the known value at the physical point."
    },
    {
        "anchor": "QCD on Coarse Lattices: We show that the perturbatively-improved gluon action for QCD, once it is\ntadpole-improved, gives accurate results even with lattice spacings as large as\n0.4~fm. {\\em No\\/} tuning of the couplings is required. Using this action and\nlattice spacing, we obtain a static potential that is rotationally invariant to\nwithin a few percent, the spin-averaged charmonium spectrum accurate to within\n30--40~MeV, and scaling to within 5--10\\%. We demonstrate that simulations on\ncoarse lattices are several orders of magnitude less costly than simulations\nusing current methods.",
        "positive": "A Conclusive Test of Abelian Dominance Hypothesis for Topological Charge\n  in the QCD Vacuum: We study the topological feature in the QCD vacuum based on the hypothesis of\nabelian dominance. The topological charge $Q_{\\rm SU(2)}$ can be explicitly\nrepresented in terms of the monopole current in the abelian dominated system.\nTo appreciate its justification, we directly measure the corresponding\ntopological charge $Q_{\\rm Mono}$, which is reconstructed only from the\nmonopole current and the abelian component of gauge fields, by using the Monte\nCarlo simulation on SU(2) lattice. We find that there exists a one-to-one\ncorrespondence between $Q_{\\rm SU(2)}$ and $Q_{\\rm Mono}$ in the maximally\nabelian gauge. Furthermore, $Q_{\\rm Mono}$ is classified by approximately\ndiscrete values."
    },
    {
        "anchor": "The Chiral Magnetic Effect and chiral symmetry breaking in SU(3)\n  quenched lattice gauge theory: We study some properties of the non-Abelian vacuum induced by strong external\nmagnetic field. We perform calculations in the quenched SU(3) lattice gauge\ntheory with tadpole-improved Luscher-Weisz action and chirally invariant\nlattice Dirac operator. The following results are obtained: The chiral symmetry\nbreaking is enhanced by the magnetic field. The chiral condensate depends on\nthe strength of the applied field as a power function with exponent n = 1.6 +/-\n0.2. There is a paramagnetic polarization of the vacuum. The corresponding\nsusceptibility and other magnetic properties are calculated and compared with\nthe theoretical estimations. There are non-zero local fluctuations of the\nchirality and electromagnetic current, which grow with the magnetic field\nstrength. These fluctuations can be a manifestation of the Chiral Magnetic\nEffect (CME).",
        "positive": "Theta vacuum physics from QCD at fixed topology: We propose a method to obtain physical quantities in the theta vacuum from\nthose at fixed topology, which are different by finite size effects. Extending\nthe work by Brower et al., we derive the formula to estimate these finite size\ncorrections for arbitrary correlators in terms of the topological\nsusceptibility and the theta dependence. Applying this formula, we show that\ntopological susceptibility can be measured through two-point functions of\npseudoscalar operator."
    },
    {
        "anchor": "Scalar glueball and meson spectroscopy in unquenched lattice QCD with\n  improved staggered quarks: We present results of an exploratory study of singlet scalar states in\nunquenched QCD using both glueball and meson operators. Results for non-singlet\nnon-strange scalar mesons are also presented. We use Asqtad improved staggered\nfermions and gauge configurations generated by the MILC collaboration at\nlattice spacings of .12 and .09 fm. In this formulation, the glueball mass is\nnot significantly different from the quenched value at finite lattice spacing.\nSignificant taste violations are present in the scalar sector. At light quark\nmasses, decay channels complicate the mass determinations. There is some\nevidence that the non-strange singlet meson lies below the non-singlet meson.",
        "positive": "Chaotic behavior of confining lattice gauge field configurations: We analyze the leading Lyapunov exponents of SU(2) Yang-Mills field\nconfigurations on the lattice which are initialized by quantum Monte Carlo\nsimulations.\n  We find that configurations in the strong coupling phase at finite\ntemperature are substantially more chaotic than in deconfinement."
    },
    {
        "anchor": "Chiral and Continuum Extrapolation of Partially-Quenched Lattice Results: The vector meson mass is extracted from a large sample of partially quenched,\ntwo-flavor lattice QCD simulations. For the first time, discretisation,\nfinite-volume and partial quenching artefacts are treated in a unified\nframework which is consistent with the low-energy behaviour of QCD. This\nanalysis incorporates the leading infrared behaviour dictated by chiral\neffective field theory. As the two-pion decay channel cannot be described by a\nlow-energy expansion alone, a highly-constrained model for the decay channel of\nthe rho-meson is introduced. The latter is essential for extrapolating lattice\nresults from the quark-mass regime where the rho is observed to be a physical\nbound state.",
        "positive": "Deconfinement in pure gauge SU(3) Yang-Mills theory: the ghost\n  propagator: The ghost propagator in Landau gauge is studied at finite temperature below\nand above $T_c$ using lattice QCD simulations. For high temperatures, we find\nthat the ghost propagator is enhanced, compared to the confined phase. The\nresults suggest that the ghost propagator can be used to identify the phase\ntransition, similarly to the gluon propagator case."
    },
    {
        "anchor": "Second Order Perturbation Theory for Improved Gluon and Staggered Quark\n  Actions: We present the results of our perturbative calculations of the static quark\npotential, small Wilson loops, the static quark self energy, and the mean link\nin Landau gauge. These calculations are done for the one loop Symanzik improved\ngluon action, and the improved staggered quark action.",
        "positive": "Baryon Operators and Baryon Spectroscopy: The issues involved in a determination of the baryon resonance spectrum in\nlattice QCD are discussed. The variational method is introduced and the need to\nconstruct a sufficient basis of interpolating operators is emphasised. The\nconstruction of baryon operators using group-theory techniques is outlined. We\nfind that the use both of quark-field smearing and link-field smearing in the\noperators is essential firstly to reduce the coupling of operators to\nhigh-frequency modes and secondly to reduce the gauge-field fluctuations in\ncorrelators. We conclude with a status report of our current investigation of\nbaryon spectroscopy."
    },
    {
        "anchor": "The road to solving the Gribov problem of the center vortex model in\n  quantum chromo dynamics: The center vortex model of the QCD vacuum is very successful in explaining\nthe non-perturbative properties of QCD, especially confinement, chiral symmetry\nbreaking and the topological charge of vacuum configurations. On the other\nhand, the center vortex model still suffers from a Gribov problem: Direct\nmaximal center gauge and center projection can lead to an underestimation of\nthe string tension in smooth configurations or after persistent simulated\nannealing. We discuss methods to identify center regions, whose boundaries\nevaluate to center elements, and want to improve the vortex detection: these\nregions might help to recognize vortices in configurations where maximal center\ngauge lost the vortex finding property.",
        "positive": "Lattice gauge theory and gluon color-confinement in curved spacetime: The lattice gauge theory for curved spacetime is formulated. A discretized\naction is derived for both gluon and quark fields which reduces to the\ngenerally covariant form in the continuum limit. Using the Wilson action, it is\nshown analytically that for a general curved spacetime background, two\npropagating gluons are always color-confined. The fermion-doubling problem is\ndiscussed in the specific case of Friedman-Robertson-Walker metric. Lastly, we\ndiscussed possible future numerical implementation of lattice QCD in curved\nspacetime."
    },
    {
        "anchor": "Numerical Study of Periodic Instanton Configurations in Two-dimensional\n  Abelian Higgs Theory: Numerical minimization of the Euclidean action of the two-dimensional Abelian\nHiggs model is used to construct periodic instantons, the euclidean field\nconfigurations with two turning points describing transitions between the\nvicinities of topologically distinct vacua. Periodic instantons are found at\nany energy ( up to the sphaleron energy $E_{sph}$ ) and for wide range of\nparameters of the theory. We obtain the dependence of the action and the energy\nof periodic instanton on its period; these quantities directly determine the\nprobability of certain multiparticle scattering events.",
        "positive": "Renormalization of a Contact Interaction on a Lattice: Contact interactions can be used to describe a system of particles at\nunitarity, contribute to the leading part of nuclear interactions and are\nnumerically non-trivial because they require a proper regularization and\nrenormalization scheme. We explain how to tune the coefficient of a contact\ninteraction between non-relativistic particles on a discretized space in 1, 2,\nand 3 spatial dimensions such that we can remove all discretization artifacts.\nBy taking advantage of a latticized L\\\"uscher zeta function, we can achieve a\nmomentum-independent scattering amplitude at any finite lattice spacing."
    },
    {
        "anchor": "The Schrodinger functional with chirally rotated boundary conditions: Using orbifold techniques I construct the Schrodinger functional (SF) for a\ndoublet of Wilson quarks with chirally rotated boundary conditions. This allows\nto perform checks of universality: for instance, the renormalized SF coupling\nconstant, defined with either boundary conditions, must have a unique continuum\nlimit. Similarly, SF correlation functions in twisted mass QCD and standard QCD\ncan be defined such that they share a common continuum limit. An additional\nbenefit of the new set-up consists in the observation that all the bulk O(a)\ncounterterms to the action and composite operators become irrelevant in the\nchiral limit. This implies that (ratios of) SF renormalization constants can be\nautomatically O(a) improved, up to the effect of unavoidable boundary\ncounterterms. As a first application we calculate the running coupling for Nf=2\nflavours in the SF-scheme to one-loop order of perturbation theory.\nUniversality of the continuum limit is confirmed and the irrelevance of the\nSheikholeslami-Wohlert term in the action is demonstrated explicitly",
        "positive": "Nonperturbative tests of the renormalization of mixed clover-staggered\n  currents in lattice QCD: The Fermilab Lattice and MILC collaborations have shown in one-loop lattice\nQCD perturbation theory that the renormalization constants of vector and\naxial-vector mixed clover-asqtad currents are closely related to the product of\nthose for clover-clover and asqtad-asqtad (local) vector currents. To be useful\nfor future higher precision calculations this relationship must be valid beyond\none-loop and very general. We test its validity nonperturbatively using clover\nand Highly Improved Staggered (HISQ) strange quarks, utilising the absolute\nnormalization of the HISQ temporal axial current. We find that the\nrenormalization of the mixed current differs from the square root of the\nproduct of the pure HISQ and pure clover currents by $2-3\\%$. We also compare\ndiscretization errors between the clover and HISQ formalisms."
    },
    {
        "anchor": "Renormalization and O(a)-improvement of the static-light axial current: A systematic treatment of O(a)-improvement in lattice theories with static\nquarks is presented. The Schr\\\"odinger functional is discussed and a\nrenormalization condition for the static axial current in the SF-scheme is\nintroduced. Its relation to other schemes is computed to 1-loop order and the\n2-loop anomalous dimension is derived. In finite volume renormalization schemes\nsuch as the SF-scheme, the renormalization scale dependence of the renormalized\nquantities is described by the step scaling function which can be computed by\nMC- simulations. We evaluate its lattice spacing effects in perturbation\ntheory.",
        "positive": "Two-loop Wess-Zumino model with exact supersymmetry on the lattice: We consider a lattice formulation of the four dimensional N=1 Wess-Zumino\nmodel in terms of the Ginsparg-Wilson relation. This formulation has an exact\nsupersymmetry on the lattice. The lattice action is invariant under a deformed\nsupersymmetric transformation which is non-linear in the scalar fields and it\nis determined by an iterative procedure in the coupling constant to all orders\nin perturbation theory. We also show that the corresponding Ward-Takahashi\nidentity is satisfied at fixed lattice spacing. The calculation is performed in\nlattice perturbation theory up to order $g^3$ (two-loop) and the Ward-Takahashi\nidentity (containing 110 connected non-tadpole Feynman diagrams) is satisfied\nat fixed lattice spacing thanks to this exact lattice supersymmetry."
    },
    {
        "anchor": "Nonlocal field correlators on the lattice in HP^1 sigma-model: Connected two-point field strength correlators have been measured on the\nlattice in quaternionic projective sigma-model of pure SU(2) Yang-Mills theory.\nThe correlation lengths, extracted from the exponential fit for these\ncorrelators, are found to be lambda_1^{-1} = 1.40(3) GeV and lambda^{-1} =\n1.51(3) GeV in good agreement with other existing calculations. The dependence\nof bilocal functions on the connector shape was studied.",
        "positive": "Multiple-particle interaction in $1+1$ dimensional lattice model: Finite volume multiple-particle interaction is studied in a two-dimensional\ncomplex $\\phi^4$ lattice model. The existence of analytical solutions to the\n$\\phi^4$ model in two-dimensional space and time makes it a perfect model for\nthe numerical study of finite volume effects of multi-particle interaction. The\nspectra from multiple particles are extracted from the Monte Carlo simulation\non various lattices in several moving frames. The $S$-matrix of multi-particle\nscattering in $\\phi^4$ theory is completely determined by two fundamental\nparameters: single particle mass and the coupling strength of two-to-two\nparticle interaction. These two parameters are fixed by studying\nsingle-particle and two-particle spectra. Due to the absence of the diffraction\neffect in the $\\phi^{4}$ model, three-particle quantization conditions are\ngiven in a simple analytical form. The three-particle spectra from simulation\nshow remarkable agreement with the prediction of exact solutions."
    },
    {
        "anchor": "Common Structures in Simplicial Quantum Gravity: The statistical properties of dynamically triangulated manifolds (DT mfds) in\nterms of the geodesic distance have been studied numerically. The string\nsusceptibility exponents for the boundary surfaces in three-dimensional DT mfds\nwere measured numerically. For spherical boundary surfaces, we obtained a\nresult consistent with the case of a two-dimensional spherical DT surface\ndescribed by the matrix model. This gives a correct method to reconstruct\ntwo-dimensional random surfaces from three-dimensional DT mfds. Furthermore, a\nscaling property of the volume distribution of minimum neck baby universes was\ninvestigated numerically in the case of three and four dimensions, and we\nobtain a common scaling structure near to the critical points belonging to the\nstrong coupling phase in both dimensions. We have evidence for the existence of\na common fractal structure in three- and four-dimensional simplicial quantum\ngravity.",
        "positive": "On the spectral density of the Wilson operator: We summarize our recent determination [1] of the spectral density of the\nWilson operator in the p-regime of Wilson chiral perturbation theory. We\ndiscuss the range of validity of our formula and a possible extension to our\ncomputation in order to better understand the behaviour of the spectral density\nin a finite volume close to the threshold."
    },
    {
        "anchor": "Scaling test of fermion actions in the Schwinger model: We discuss the scaling behaviour of different fermion actions in dynamical\nsimulations of the 2-dimensional massive Schwinger model. We have chosen\nWilson, hypercube, twisted mass and overlap fermion actions. As physical\nobservables, the pion mass and the scalar condensate are computed for the above\nmentioned actions at a number of coupling values and fermion masses. We also\ndiscuss possibilities to simulate overlap fermions dynamically avoiding\nproblems with low-lying eigenvalues of the overlap kernel.",
        "positive": "Finite volume effects on the electric polarizability of neutral hadrons\n  in lattice QCD: We study the finite volume effects on the electric polarizability for the\nneutron, neutral pion, and neutral kaon using eight dynamically generated\ntwo-flavor nHYP-clover ensembles at two different pion masses: 306(1) and\n227(2) MeV. An infinite volume extrapolation is performed for each hadron at\nboth pion masses. For the neutral kaon, finite volume effects are relatively\nmild. The dependence on the quark mass is also mild and a reliable chiral\nextrapolation can be performed along with the infinite volume extrapolation.\nOur result is $\\alpha_{K^0}^\\mbox{phys}=0.356(74) \\times 10^{-4} \\mbox{fm}^3$.\nIn contrast, for neutron the electric polarizability depends strongly on the\nvolume. After removing the finite volume corrections, our neutron\npolarizability results are in good agreement with $\\chi$PT. For the connected\npart of the neutral pion polarizability, the negative trend persists, and it is\nnot due to finite volume effects, but likely sea quark charging effects."
    },
    {
        "anchor": "Logarithmic corrections to $\\mathbf{a^2}$ scaling in lattice QCD with\n  Wilson and Ginsparg-Wilson quarks: We analyse the leading logarithmic corrections to the $a^2$ scaling of\nlattice artefacts in QCD, following the seminal work of Balog, Niedermayer and\nWeisz in the O(n) non-linear sigma model. Limiting the discussion to\ncontributions from the action, the leading logarithmic corrections can be\ndetermined by the anomalous dimensions of mass-dimension 6 operators. These\noperators form a minimal on-shell basis of the Symanzik Effective Theory. We\npresent results for non-perturbatively O($a$) improved Wilson and\nGinsparg-Wilson quarks.",
        "positive": "Pure gauge glueballs at finite temperature: Pure gauge glueballs at finite temperature are investigated in a large\ntemperature range from $0.3T_c$ to $1.9T_c$ on anisotropic lattices. Optimized\nglueball operators are used to obtain better signals. It is found in all 20\nsymmetry channels that the pole masses $M_G$ of glueballs remain almost\nconstants when the temperature approaches the critical temperature $T_c$ from\nbelow, and start to reduce gradually with the temperature going above $T_c$.\nThe glueball correlators in $0^{++}$, $0^{-+}$, and $2^{++}$ channels, are also\nanalyzed based on the Breit-Wigner ansatz by assuming a thermal width $\\Gamma$\nto the pole mass $\\omega_0$. While $\\omega_0$'s are insensitive to $T$ in the\nwhole temperature range, $\\Gamma$'s exhibit distinct behavior below and above\n$T_c$: They are only few percents of $\\omega_0$ when $T<T_c$, but grow abruptly\nwhen $T>T_c$ and reach values of roughly $\\Gamma\\sim \\omega_0/2$ at $T\\approx\n1.9T_c$."
    },
    {
        "anchor": "$f_B$ quenched and unquenched: Results for $f_B$, $f_{B_s}$, $f_D$, $f_{D_s}$, and their ratios are\npresented. High statistics quenched runs at $\\beta=5.7$, $5.85$, $6.0$, and\n$6.3$, plus a run still in progress at $\\beta=6.52$ make possible a preliminary\nextrapolation to the continuum. The data allows good control of all systematic\nerrors except for quenching, although not all of the error estimates have been\nfinalized. Results from configurations which include effects of dynamical\nquarks show a significant deviation from the quenched results and make possible\na crude estimate of the quenching error.",
        "positive": "Chiral logs in twisted mass lattice QCD with large isospin breaking: The pion masses and the pion decay constant are calculated to 1-loop order in\ntwisted mass Wilson chiral perturbation theory, assuming a large pion mass\nsplitting and tuning to maximal twist. Taking the large mass splitting at\nleading order in the chiral expansion leads to significant modifications in the\nchiral logarithms. For example, the result for the charged pion mass contains a\nchiral logarithm that involves the neutral pion mass instead of the charged\none. Similar modifications appear in the results for the neutral pion mass and\nthe decay constant. These new results are used in fits to lattice data obtained\nrecently by the European twisted mass collaboration. The data can be fitted\nwell, in general better than with the standard chiral perturbation theory\nexpressions that ignore the mass splitting. The impact on the extraction of\nlow-energy couplings is briefly discussed."
    },
    {
        "anchor": "The QCD spectrum with three quark flavors: We present results from a lattice hadron spectrum calculation using three\nflavors of dynamical quarks - two light and one strange, and quenched\nsimulations for comparison. These simulations were done using a one-loop\nSymanzik improved gauge action and an improved Kogut-Susskind quark action. The\nlattice spacings, and hence also the physical volumes, were tuned to be the\nsame in all the runs to better expose differences due to flavor number. Lattice\nspacings were tuned using the static quark potential, so as a byproduct we\nobtain updated results for the effect of sea quarks on the static quark\npotential. We find indications that the full QCD meson spectrum is in better\nagreement with experiment than the quenched spectrum. For the 0++ (a0) meson we\nsee a coupling to two pseudoscalar mesons, or a meson decay on the lattice.",
        "positive": "Applications of flow models to the generation of correlated lattice QCD\n  ensembles: Machine-learned normalizing flows can be used in the context of lattice\nquantum field theory to generate statistically correlated ensembles of lattice\ngauge fields at different action parameters. This work demonstrates how these\ncorrelations can be exploited for variance reduction in the computation of\nobservables. Three different proof-of-concept applications are demonstrated\nusing a novel residual flow architecture: continuum limits of gauge theories,\nthe mass dependence of QCD observables, and hadronic matrix elements based on\nthe Feynman-Hellmann approach. In all three cases, it is shown that statistical\nuncertainties are significantly reduced when machine-learned flows are\nincorporated as compared with the same calculations performed with uncorrelated\nensembles or direct reweighting."
    },
    {
        "anchor": "Perturbative expansion of the energy of static sources at large orders\n  in four-dimensional SU(3) gauge theory: We determine the infinite volume coefficients of the perturbative expansions\nof the self-energies of static sources in the fundamental and adjoint\nrepresentations in SU(3) gluodynamics to order \\alpha^{20} in the strong\ncoupling parameter \\alpha. We use numerical stochastic perturbation theory,\nwhere we employ a new second order integrator and twisted boundary conditions.\nThe expansions are obtained in lattice regularization with the Wilson action\nand two different discretizations of the covariant time derivative within the\nPolyakov loop. Overall, we obtain four different perturbative series. For all\nof them the high order coefficients display the factorial growth predicted by\nthe conjectured renormalon picture, based on the operator product expansion.\nThis enables us to determine the normalization constants of the leading\ninfrared renormalons of heavy quark and heavy gluino pole masses and to\ntranslate these into the modified minimal subtraction scheme (MS). We also\nestimate the four-loop \\beta-function coefficient of the lattice scheme.",
        "positive": "On the degrees of freedom of lattice electrodynamics: Using Euler's formula for a network of polygons for 2D case (or polyhedra for\n3D case), we show that the number of dynamic\\textit{\\}degrees of freedom of the\nelectric field equals the number of dynamic degrees of freedom of the magnetic\nfield for electrodynamics formulated on a lattice. Instrumental to this\nidentity is the use (at least implicitly) of a dual lattice and of a (spatial)\ngeometric discretization scheme based on discrete differential forms. As a\nby-product, this analysis also unveils a physical interpretation for Euler's\nformula and a geometric interpretation for the Hodge decomposition."
    },
    {
        "anchor": "$\u03c1$ mesons in strong abelian magnetic field in SU(3) lattice gauge\n  theory: We explore the masses of neutral and charged $\\rho$ mesons in strong abelian\nmagnetic field in $SU(3)$ gluodynamics. The behaviour of the ground state\nenergy of these particles in the external magnetic field depends on its spin\nprojection $s_z$ on the axis of external magnetic field. The masses of $\\rho^0$\nmeson with $s_z=\\pm 1$ increase with the field. The masses of $\\rho^{\\pm}$\nmesons with zero spin also grow with the magnetic field. The ground state\nenergies of $\\rho^{-}$ meson with $s_z=-1$ and $\\rho^{+}$ meson with $s_z=+1$\ndiminish as a function of the field, while the energies of $\\rho^{+}$ meson\nwith $s_z=-1$ and $\\rho^{-}$ meson with $s_z=+1$ rise with the field value.",
        "positive": "Staggered Fermion Thermodynamics using Anisotropic Lattices: Numerical simulations of full QCD on anisotropic lattices provide a\nconvenient way to study QCD thermodynamics with fixed physics scales and\nreduced lattice spacing errors. We report results from calculations with\n2-flavors of dynamical fermions where all bare parameters and hence the physics\nscales are kept constant while the temperature is changed in small steps by\nvarying only the number of the time slices. The results from a series of\nzero-temperature scale setting simulations are used to determine the Karsch\ncoefficients and the equation of state at finite temperatures."
    },
    {
        "anchor": "A Dedicated Computer for Ising-like Spin Glass Models: We present a parallel machine, based on programmable devices, dedicated to\nsimulate spin glass models with Z2 variables and short range interaction. A\nworking prototype is described for two lattices containing 312x312 spins each\nwith an update time of 50 ns per spin. The final version of the three\ndimensional parallel machine is discussed with spin update time up to 312 ps.",
        "positive": "Dynamical Simulations with Smeared Link Staggered Fermions: One of the most serious problems of the staggered fermion lattice action is\nflavor symmetry violation. Smeared link staggered fermions can improve flavor\nsymmetry by an order of magnitude relative to the standard thin link action.\nOver the last few years different smearing transformations have been proposed,\nboth with perturbatively and non-perturbatively determined coefficients. What\nhindered the acceptance and more general use of smeared link fermions until now\nis the relative difficulty of dynamical simulations and the lack of\nperturbative calculations with these actions. In both areas there have been\nsignificant improvement lately, that I will review in this paper."
    },
    {
        "anchor": "Real space renormalization group for twisted lattice N=4 super\n  Yang-Mills: A necessary ingredient for our previous results on the form of the long\ndistance effective action of the twisted lattice N=4 super Yang-Mills theory is\nthe existence of a real space renormalization group which preserves the lattice\nstructure, both the symmetries and the geometric interpretation of the fields.\nIn this brief article we provide an explicit example of such a blocking scheme\nand illustrate its practicality in the context of a small scale Monte Carlo\nrenormalization group calculation. We also discuss the implications of this\nresult, and the possible ways in which to use it in order to obtain further\ninformation about the long distance theory.",
        "positive": "Color confinement and dual superconductivity in unquenched QCD: We report on evidence from lattice simulations that confinement is produced\nby dual superconductivity of the vacuum in full QCD as in quenched QCD.\nPreliminary information is obtained on the order of the deconfining phase\ntransition."
    },
    {
        "anchor": "String breaking in SU(2) gauge theory with scalar matter fields: We investigate the static potential in the confinement phase of the SU(2)\nHiggs model on the lattice, where this model is expected to have properties\nsimilar to QCD. We observe that Wilson loops are inadequate to determine the\npotential at large distances, where the formation of two color-neutral mesons\nis expected. Introducing smeared fields and a suitable matrix correlation\nfunction, we are able to overcome this difficulty. We observe string breaking\nat a distance $r_b \\approx 1.8 r_0$, where the length scale $r_0$ has a value\n$r_0 \\approx 0.5 fm$ in QCD. The method presented here may lead the way towards\na treatment of string breaking in QCD.",
        "positive": "Dual variables for the SU(2) lattice gauge theory at finite temperature: We study the three-dimensional SU(2) lattice gauge theory at finite\ntemperature using an observable which is dual to the Wilson line. This\nobservable displays a behaviour which is the reverse of that seen for the\nWilson line. It is non-zero in the confined phase and becomes zero in the\ndeconfined phase. At large distances, it's correlation function falls off\nexponentially in the deconfined phase and remains non-zero in the confined\nphase. The dual variable is non-local and has a string attached to it which\ncreates a Z(2) interface in the system. It's correlation function measures the\nstring tension between oppositely oriented Z(2) domains. The construction of\nthis variable can also be made in the four-dimensional theory where it measures\nthe surface tension between oppositely oriented Z(2) domains."
    },
    {
        "anchor": "Mass anomalous dimension of SU(2) using the spectral density method: SU(2) with N_f = 6 and N_f = 8 are believed to have an infrared conformal\nfixed point. We use the spectral density method cross referenced with the mass\nstep scaling method to evaluate the coupling constant dependence of the mass\nanomalous dimension for massless HEX smeared, clover improved Wilson fermions\nwith Schr\\\"odinger functional boundary conditions.",
        "positive": "Status of the Lambda Lattice Scale for the SU(3) Wilson gauge action: With the emergence of the Yang-Mills gradient flow technique there is renewed\ninterest in the issue of scale setting in lattice gauge theory. Here I compare\nfor the SU(3) Wilson gauge action non-perturbative scale functions of Edwards,\nHeller and Klassen (EHK), Necco and Sommer (NS), both relying on Sommer's\nmethod using the quark potential, and the scale function derived by Bazavov,\nBerg and Velytsky (BBV) from a deconfining phase transition investigation by\nthe Bielefeld group. It turns out that the scale functions are based on\nmutually inconsistent data, though the BBV scale function is consistent with\nthe EHK data when their low $\\beta$ ($\\beta=5.6$) data point is removed.\nBesides, only the BBV scale function is consistent with three data points\ncalculated from the gradient flow by L\\\"uscher. In the range for which data\nexist the discrepancies between the scale functions are only up to $\\pm 2$\\% of\ntheir values, but clearly visible within the statistical accuracy."
    },
    {
        "anchor": "Tensor RG calculations and quantum simulations near criticality: We discuss the reformulation of the O(2) model with a chemical potential and\nthe Abelian Higgs model on a 1+1 dimensional space-time lattice using the\nTensor Renormalization Group (TRG) method. The TRG allows exact blocking and\nconnects smoothly the classical Lagrangian approach to the quantum Hamiltonian\napproach. We calculate the entanglement entropy in the superfluid phase of the\nO(2) model and show that it approximately obeys the logarithmic Calabrese-Cardy\nscaling obtained from Conformal Field Theory (CFT). We calculate the Polyakov\nloop in the Abelian Higgs model and discuss the possibility of a deconfinement\ntransition at finite volume. We propose Bose-Hubbard Hamiltonians implementable\non optical lattices as quantum simulators for CFT models.",
        "positive": "The finite temperature QCD phase transition with domain wall fermions: The domain wall formulation of lattice fermions is expected to support\naccurate chiral symmetry, even at finite lattice spacing. Here we attempt to\nuse this new fermion formulation to simulate two-flavor, finite temperature QCD\nnear the chiral phase transition. In this initial study, a variety of quark\nmasses, domain wall heights and domain wall separations are explored using an\n8^3 x 4 lattice. Both the expectation value of the Wilson line and the chiral\ncondensate show the temperature dependence expected for the QCD phase\ntransition. Further, the desired chiral properties are seen for the chiral\ncondensate, suggesting that the domain wall fermion formulation may be an\neffective approach for the numerical study of QCD at finite temperature."
    },
    {
        "anchor": "The Physical Phase of Dimensionally Reduced Gauge Theories: We investigate the relationship between the high temperature deconfined phase\nof the SU(2) gauge theory to the phases of the corresponding three dimensional\nadjoint Higgs model. For various temperatures we simulate the effective theory\nin a neighbourhood of the physical states, that is of those values of the\ncoupling constants that describe the infrared behaviour of the four dimensional\ntheory and which have been calculated by applying dimensional reduction\ntechniques. We show that the physical points belong to the confined phase of\nthe SU(2) adjoint Higgs model.",
        "positive": "Light vector meson decay constants and the renormalization factor from a\n  tadpole-improved action: The rho, K* and phi decay constants and the vector current renormalization\nfactor are studied by using an O(a^2) classically-improved, tadpole-improved\naction. Tree-level calculations are used to show how the classical improvement\nof the action, involving next-nearest-neighbour timesteps, is transferred to\nthe matrix elements. Simulations are performed on coarse lattices and compared\nto Wilson results from both coarse and fine lattices. The improved action data\nare found to resemble Wilson data obtained at 1/3 of the lattice spacing, which\nis the same degree of improvement that is seen by comparing the mass spectra."
    },
    {
        "anchor": "The QCD crossover at finite chemical potential from lattice simulations: We provide the most accurate results for the QCD transition line so far. We\noptimize the definition of the crossover temperature $T_c$, allowing for its\nvery precise determination, and extrapolate from imaginary chemical potential\nup to real $\\mu_B \\approx 300$ MeV. The definition of $T_c$ adopted in this\nwork is based on the observation that the chiral susceptibility as a function\nof the condensate is an almost universal curve at zero and imaganiary $\\mu_B$.\nWe obtain the parameters $\\kappa_2=0.0153(18)$ and $\\kappa_4=0.00032(67)$ as a\ncontinuum extrapolation based on $N_t=10,12$ and $16$ lattices with physical\nquark masses. We also extrapolate the peak value of the chiral susceptibility\nand the width of the chiral transition along the crossover line. In fact, both\nof these are consistent with a constant function of $\\mu_B$. We see no sign of\ncriticality in the explored range.",
        "positive": "Up and down quark masses and corrections to Dashen's theorem from\n  lattice QCD and quenched QED: In a previous letter (arXiv:1306.2287) we determined the isospin mass\nsplittings of the baryon octet from a lattice calculation based on quenched QED\nand $N_f{=}2{+}1$ QCD simulations with 5 lattice spacings down to\n$0.054~\\mathrm{fm}$, lattice sizes up to $6~\\mathrm{fm}$ and average up-down\nquark masses all the way down to their physical value. Using the same data we\ndetermine here the corrections to Dashen's theorem and the individual up and\ndown quark masses. For the parameter which quantifies violations to Dashens's\ntheorem, we obtain $\\epsilon=0.73(2)(5)(17)$, where the first error is\nstatistical, the second is systematic, and the third is an estimate of the QED\nquenching error. For the light quark masses we obtain,\n$m_u=2.27(6)(5)(4)~\\mathrm{MeV}$ and $m_d=4.67(6)(5)(4)~\\mathrm{MeV}$ in the\n$\\bar{\\mathrm{MS}}$ scheme at $2~\\mathrm{GeV}$ and the isospin breaking ratios\n$m_u/m_d=0.485(11)(8)(14)$, $R=38.2(1.1)(0.8)(1.4)$ and\n$Q=23.4(0.4)(0.3)(0.4)$. Our results exclude the $m_u=0$ solution to the strong\nCP problem by more than $24$ standard deviations."
    },
    {
        "anchor": "Topology in high-$T$ QCD via staggered spectral projectors: We present preliminary lattice results for the topological susceptibility in\nhigh-$T$ $N_f=2+1$ QCD obtained discretizing this observable via spectral\nprojectors on eigenmodes of the staggered operator, and we compare them with\nthose obtained with the standard gluonic definition. The adoption of the\nspectral discretization is motivated by the large lattice artifacts affecting\nthe continuum scaling of the gluonic susceptibility at high $T$, related to the\nchoice of non-chiral fermions in the action.",
        "positive": "The lattice gluon propagator into the next millennium: We evaluate numerically the momentum-space gluon propagator in the lattice\nLandau gauge, for three- and four-dimensional pure SU(2) lattice gauge theory.\nAlthough there are large finite-size effects, we always observe, in the limit\nof large lattice volumes, a gluon propagator decreasing in the infrared limit.\nThis result can be interpreted in a straightforward way, by considering the\nproximity of the so-called first Gribov horizon in the infrared directions. We\nalso consider the problem of discretization errors introduced by the lattice\nregularization, and their effect on the ultraviolet behavior of the gluon\npropagator."
    },
    {
        "anchor": "Improved Langevin Methods for Spin Systems: We investigate methods for variance reduction and the elimination of\nsystematic error in a Fourier accelerated Langevin scheme for general spin\nmodels. We present results for the $SU(3)\\times SU(3)/SU(3)$ model in\ntwo-dimensions that are consistent wit h those from multi-grid methods. We\nargue that the timing for the Langevin method makes it comparable to multi-grid\nfor a given level of error.",
        "positive": "Finite volume effects and quark mass dependence of the N(1535) and\n  N(1650): For resonances decaying in a finite volume, the simple identification of\nstate and eigenvalue is lost. The extraction of the scattering amplitude is a\nmajor challenge as we demonstrate by extrapolating the physical S_{11}\namplitude of pion-nucleon scattering to the finite volume and unphysical quark\nmasses, using a unitarized chiral framework including all next-to-leading order\ncontact terms. We show that the pole movement of the resonances N(1535)1/2^-\nand N(1650)1/2^- with varying quark masses is non-trivial. In addition, there\nare several strongly coupled S-wave thresholds that induce a similar avoided\nlevel crossing as narrow resonances. The level spectrum is predicted for two\ntypical lattice setups, and ways to extract the amplitude from upcoming lattice\ndata are discussed."
    },
    {
        "anchor": "N and N to Delta transition form factors from Lattice QCD: We present recent lattice QCD results on nucleon form factors and N to Delta\ntransition form factors. We predict the parity violating asymmetry in N to\nDelta and check the off-diagonal Goldberger-Treiman relation.",
        "positive": "Critical Exponents of the Classical 3D Heisenberg Model: A\n  Single-Cluster Monte Carlo Study: We have simulated the three-dimensional Heisenberg model on simple cubic\nlattices, using the single-cluster Monte Carlo update algorithm. The expected\npronounced reduction of critical slowing down at the phase transition is\nverified. This allows simulations on significantly larger lattices than in\nprevious studies and consequently a better control over systematic errors. In\none set of simulations we employ the usual finite-size scaling methods to\ncompute the critical exponents $\\nu,\\alpha,\\beta,\\gamma, \\eta$ from a few\nmeasurements in the vicinity of the critical point, making extensive use of\nhistogram reweighting and optimization techniques. In another set of\nsimulations we report measurements of improved estimators for the spatial\ncorrelation length and the susceptibility in the high-temperature phase,\nobtained on lattices with up to $100^3$ spins. This enables us to compute\nindependent estimates of $\\nu$ and $\\gamma$ from power-law fits of their\ncritical divergencies."
    },
    {
        "anchor": "Direct access to hadronic decay parameters with twisted boundary\n  conditions: Our exploratory study looks for direct access to the resonant hadronic\ntransition amplitude without resorting to the L\\\"uscher formalism. We study the\ndecay $\\Psi(3770)\\to\\bar{D}D$ by applying partially twisted boundary conditions\nto the quenched charm quark, circumventing possible problems with final state\ninteractions. If successful, we could compute the dependence of the transition\namplitude on the charm-quark mass and test the predictions made by\nphenomenological quark-pair-creation models. Finally, we study if and to what\nextent an extraction of the excited state $\\Psi(3770)$ is necessary for this\nanalysis.",
        "positive": "The nucleon electromagnetic form factors from Lattice QCD: We evaluate the isovector nucleon electromagnetic form factors in quenched\nand full QCD on the lattice using Wilson fermions. In the quenched theory we\nuse a lattice of spatial size 3 fm at beta=6.0 enabling us to reach low\nmomentum transfers and a lowest pion mass of about 400 MeV. In the full theory\nwe use a lattice of spatial size 1.9 fm at beta=5.6 and lowest pion mass of\nabout 380 MeV enabling comparison with the results obtained in the quenched\ntheory. We compare our lattice results to the isovector part of the\nexperimentally measured form factors."
    },
    {
        "anchor": "Real-Time-Evolution of Heavy Quarks in the Glasma: We introduce a novel real-time formulation of lattice NRQCD designed for\nsimulations in the background of an highly occupied gluon field. By evolving\nquarks in the background of a dynamically evolving gluon field we computed the\ntime-evolution of heavy-quarkonium spectral functions as well as the static and\nfor finitely heavy quarks generalised potential. We conclude that the back\nreaction of the quarks is necessary for any binding process. Here we discuss\nthe methodology, our results and the origin of the absence of a binding\nprocess.",
        "positive": "Approaching the Bottom Using Fine Lattices With Domain-Wall Fermions: We explore the heavy-quark mass region above the charm mass using M\\\"obius\ndomain-wall fermions on fine lattices at $a = 0.080$, $0.055$, and $0.044$ fm.\nWe examine masses and decay constants using a series of heavy quark masses up\nto 3 times the charm quark. We analyze the cutoff effects for heavy quarks\nabove the charm and account for the leading order discretization effects using\nideas from HQET. We extrapolate to the bottom quark mass and report preliminary\nresults for $f_{B}$ and $f_{B_s}$"
    },
    {
        "anchor": "Dual condensate and QCD phase transition: The dual condensate is a new QCD phase transition order parameter, which\nconnnects confinement and chiral symmetry breaking as different mass limits. We\ndiscuss the relation between the fermion spectrum at general boundary\nconditions and the dual condensate and show numerical results for the latter\nfrom unquenched SU(3) lattice configurations.",
        "positive": "Lattice QCD at finite temperature: some aspects related to chiral\n  symmetry: Out of the many exciting results obtained with the lattice approach to QCD\nunder extreme conditions, I discuss a few selected items related to chiral\nsymmetry: the chiral condensate as an approximate order parameter, meson\nscreening masses, and masses of baryons and mesons, including D(s) mesons, when\napproaching the crossover from the hadronic side."
    },
    {
        "anchor": "Cutoff effects of Wilson fermions in the absence of spontaneous chiral\n  symmetry breaking: We simulate two dimensional QED with two degenerate Wilson fermions and\nplaquette gauge action. As a consequence of the Mermin-Wagner theorem, in the\ncontinuum limit chiral symmetry is realized a la Wigner. This property affects\nalso the size of the cutoff effects. That can be understood in view of the fact\nthat the leading lattice artifacts are described, in the continuum Symanzik\neffective theory, by chirality breaking terms. In particular, vacuum\nexpectation values of non-chirality-breaking operators are expected to be O(a)\nimproved in the chiral limit. We provide a numerical confirmation of this\nexpectation by performing a scaling test.",
        "positive": "Light Quark Physics on Different Lattices: The light quark results from three different simulations are summarized. We\nget consistent results, within our statistics, between smeared and non smeared\ndata. A comparison is performed with similar results from the UKQCD\ncollaboration. All runs have been performed on two 6.4 GF APE computers\n\\cite{tubo}."
    },
    {
        "anchor": "Link smearing considered as MCRG transformation: Gauge link smearing is widely used in lattice QCD computations. The idea is\nto remove the local (UV) fluctuations of the gauge field configurations while\nkeeping the longer-range (IR) properties intact. Important applications are in\nthe definitions of interpolating hadron operators as well as in updating the\ngauge field configurations with dynamical quarks in the so-called Hybrid Monte\nCarlo (HMC) algorithm. Here we study the effectiveness of various smearing\nmethods and try to quantify these with tools known from Monte Carlo\nRenormalization Group (MCRG).",
        "positive": "Dynamical QCD simulation with theta terms: The theta term that breaks the Strong CP symmetry is introduced in the two\nflavors of dynamical QCD simulation. theta is analytically continued to a pure\nimaginary number to make the probability of Monte Carlo positive. The Neutron's\nElectric Dipole Moment (NEDM) is measured on the ensemble under a uniform and\nweek electric field. Other applications of theta terms are also discussed."
    },
    {
        "anchor": "Improved analysis of nucleon isovector charges and twist-2 matrix\n  elements on CLS $N_f=2+1$ ensembles: Preliminary results are presented for nucleon isovector charges and twist-2\nmatrix elements which have been obtained employing an improved analysis\nstrategy to deal with excited-state contamination. The set of CLS $N_f=2+1$\ngauge ensembles in this study has been extended compared to our 2018\ncalculation, including an ensemble at physical quark masses. Besides the\naddition of new ensembles, the number of gauge configurations and measurements\nhas been increased on several of the existing ensembles and the analysis has\nbeen extended to include additional source-sink separations. The ensembles\ncover a range of the light quark mass corresponding to $M_\\pi\\approx\n0.130\\,\\mathrm{MeV} \\ldots 350\\,\\mathrm{MeV}$, four values of the lattice\nspacing $a\\approx0.05\\,\\mathrm{fm}\\ldots0.09\\,\\mathrm{fm}$ and a large range of\nvolumes. Results at the physical point are computed for each observable from a\ncombined chiral, continuum and finite-volume extrapolation.",
        "positive": "Heavy-light meson decay constants with N_f=3: During the past year the MILC Collaboration has continued its study of\nheavy-light meson decay constants with three dynamical quarks. Calculations\nhave been extended to a second lattice spacing of about 0.09 fm. At this\nlattice spacing, there are results in the quenched approximation and for three\nsets of dynamical quark mass: m_l=m_s; m_l=0.4 m_s and m_l=0.2 m_s, where m_l\nis the light mass for the u and d quarks and m_s is the strange quark mass. At\nthe coarser lattice spacing, for which results were presented at Lattice 2001,\nstatistics have been increased for two sets of quark masses and three\nadditional sets of quark masses have been studied, giving a total of eight\ncombinations used to interpolate between the quenched and chiral limits. When\nthese calculations are completed, we can study the decay constants taking into\naccount both chiral and continuum extrapolations."
    },
    {
        "anchor": "Second Moment of the Pion Light-cone Distribution Amplitude from Lattice\n  QCD: We present the results of a lattice study of the second moment of the\nlight-cone pion distribution amplitude using two flavors of dynamical (clover)\nfermions on lattices of different volumes and pion masses down to $m_\\pi\\sim\n150 \\, \\mathrm {MeV}$. At lattice spacings between $0.06 \\, \\mathrm {fm}$ and\n$0.08 \\, \\mathrm {fm}$ we find for the second Gegenbauer moment the value $a_2\n= 0.1364(154)(145)$ at the scale $\\mu=2 \\, \\mathrm {GeV}$ in the\n$\\overline{\\mathrm{MS}}$ scheme, where the first error is statistical including\nthe uncertainty of the chiral extrapolation, and the second error is the\nestimated uncertainty coming from the nonperturbatively determined\nrenormalization factors.",
        "positive": "Speeding up HMC with better integrators: We discuss how dynamical fermion computations may be made yet cheaper by\nusing symplectic integrators that conserve energy much more accurately without\ndecreasing the integration step size. We first explain why symplectic\nintegrators exactly conserve a ``shadow'' Hamiltonian close to the desired one,\nand how this Hamiltonian may be computed in terms of Poisson brackets. We then\ndiscuss how classical mechanics may be implemented on Lie groups and derive the\nform of the Poisson brackets and force terms for some interesting integrators\nsuch as those making use of second derivatives of the action (Hessian or force\ngradient integrators). We hope that these will be seen to greatly improve\nenergy conservation for only a small additional cost and that their use will\nsignificantly reduce the cost of dynamical fermion computations."
    },
    {
        "anchor": "Hadronic contribution to g-2 from twisted mass fermions: We calculate the vacuum polarization tensor for pion masses from 480 MeV to\n270 MeV using dynamical twisted mass fermions at a lattice spacing of 0.086 fm.\nWe analyze the form of the polarization tensor on the lattice using the\nsymmetries of twisted QCD and we study both finite size effects and lattice\nartifacts at a pion mass of 310 MeV. Results for the lowest order hadronic\ncontribution to g-2 are presented and the impact of systematic errors is\ndiscussed.",
        "positive": "Worldline approach to few-body physics on the lattice: We study the physics of two species of non-relativistic hard-core bosons with\nattractive or repulsive delta function interactions on a spacetime lattice\nusing the worldline formulation. By tuning the chemical potential carefully we\nshow that worm algorithms can efficiently sample the worldline configurations\nin any fixed particle-number sector. Since fermions can be treated as hard-core\nbosons up to a permutation sign, we also apply this approach to\nnon-relativistic fermions. The fermion permutation sign is treated as an\nobservable in this approach and can be used to extract energies for each\nparticle-number sector. Since in one dimension non-relativistic fermions can\nonly permute due to boundary effects, unlike the auxiliary field method, in\nmany cases our approach does not suffer from sign problems. Using our method we\ndiscover limitations of the recently proposed complex Langevin calculations in\none dimension."
    },
    {
        "anchor": "Charmonium Spectrum from Quenched QCD with Overlap Fermions: We present the first study of the charmonium spectrum using overlap fermions,\non quenched configurations. Simulations are performed on $16^3 \\times 72$\nlattices, with Wilson gauge action at $\\beta$ = 6.3345. We demonstrate that we\nhave discretization errors under control at about 5%. We obtain 88(4) MeV for\nhyperfine splitting using the $r_0$ scale, and 121(6) MeV using the\n($1\\bar{P}-1\\bar{S}$) scale. This paper raises the possibility that the\ndiscrepancy between the lattice results and the experimental value for\ncharmonium hyperfine splitting can be resolved using overlap fermions to\nsimulate the charm quark on lattice.",
        "positive": "Sampling QCD field configurations with gauge-equivariant flow models: Machine learning methods based on normalizing flows have been shown to\naddress important challenges, such as critical slowing-down and topological\nfreezing, in the sampling of gauge field configurations in simple lattice field\ntheories. A critical question is whether this success will translate to studies\nof QCD. This Proceedings presents a status update on advances in this area. In\nparticular, it is illustrated how recently developed algorithmic components may\nbe combined to construct flow-based sampling algorithms for QCD in four\ndimensions. The prospects and challenges for future use of this approach in\nat-scale applications are summarized."
    },
    {
        "anchor": "A General Method for Non-Perturbative Renormalization of Lattice\n  Operators: We propose a non-perturbative method for computing the renormalization\nconstants of generic composite operators. This method is intended to reduce\nsome systematic errors, which are present when one tries to obtain physical\npredictions from the matrix elements of lattice operators. We also present the\nresults of a calculation of the renormalization constants of several\ntwo-fermion operators, obtained, with our method, by numerical simulation of\n$QCD$, on a $16^3 \\times 32$ lattice, at $\\beta=6.0$. The results of this\nsimulation are encouraging, and further applications to four-fermion operators\nand to the heavy quark effective theory are proposed.",
        "positive": "On the topological structure of the QCD vacuum: A review of results from lattice studies using improved and scale controlled\ncooling methods is presented and their significance is discussed. The\nimprovement of the action ensures stable instanton solutions of physical sizes.\nThe scale controlled cooling can be generally used as a gauge invariant low\npass filter to extract the physics from noisy MC configurations; in particular\nit preserves instanton-antiinstanton pairs selected according to their\ninteraction. We apply these methods to analyze various features of the\ntopological structure of the Yang-Mills vacuum in a scaling invariant way."
    },
    {
        "anchor": "Precision study of the SU(3) topological susceptibility in the continuum: We determine the topological susceptibility in the SU(3) pure gauge theory.\nWe perform a series of high-statistics lattice studies and take the combined\ncontinuum and infinite volume limit. We find chi_{top}r_0^4=0.0524(7)(6) which\ntranslates into chi_{top}^{1/4}=193(1)(8)MeV with the second error exclusively\ndue to the intrinsic scale ambiguity.",
        "positive": "Mass anomalous dimension from Dirac eigenmode scaling in conformal and\n  confining systems: The mode number of the Dirac operator scales with an exponent related to the\nmass anomalous dimension gamma_m. This relation holds both in IR-conformal\nsystems, as well as in confining systems for large enough eigenvalues. We\ninvestigate the Nf=4, 8 and 12 flavor SU(3) systems at several couplings near\nthe chiral limit, and show that in general the scaling exponent varies with the\neigenvalue, describing the dependence of gamma_m on the energy (or,\nequivalently, on the running coupling). This energy dependence can be explored\neven with fixed lattice parameters (bare coupling and mass). We find that for\nthe 4 flavor system the mass anomalous dimension decreases as the energy\nincreases, consistent with perturbative expectations. For the 8 flavor system\nthe energy dependence is too weak to be observable at present. The 12 flavor\nsystem at our strongest couplings shows the anomalous dimension increasing with\nenergy, consistent with backward flow and the presence of an infrared fixed\npoint. At weaker couplings we determine a preliminary value for the mass\nanomalous dimension of the 12 flavor system at the infrared fixed point,\ngamma_m^*=0.27(3)."
    },
    {
        "anchor": "Monopole Condensation in Lattice SU(2) QCD: This is the short review of Monte-Carlo studies of quark confinement in\nlattice QCD. After abelian projections both in the maximally abelian and\nPolyakov gauges, it is seen that the monopole part alone is responsible for\nconfinement. A block spin transformation on the dual lattice suggests that\nlattice $SU(2)$ QCD is always ( for all $\\beta$) in the monopole condensed\nphase and so in the confinement phase in the infinite volume limit.",
        "positive": "Spectral Methods in Causal Dynamical Triangulations: We show recent results of the application of spectral analysis in the setting\nof the Monte Carlo approach to Quantum Gravity known as Causal Dynamical\nTriangulations (CDT), discussing the behavior of the lowest lying eigenvalues\nof the Laplace-Beltrami operator computed on spatial slices. This kind of\nanalysis provides information about running scales of the theory and about the\ncritical behaviour around a possible second order transition in the CDT phase\ndiagram, discussing the implications for the continuum limit."
    },
    {
        "anchor": "B^0_s and B^0 Mixing in the Standard Model and Beyond: A Progress Report: We give a progress report on the calculation of B meson mixing matrix\nelements, focusing on contributions that could arise beyond the Standard Model.\nThe calculation uses asqtad (light quark) and Fermilab (heavy quark) valence\nactions and MILC ensembles with 2+1 flavors of asqtad sea quarks. We report\npreliminary B^0_s fit results, at a lattice spacing of 0.12 fm, for the SUSY\nbasis of effective four-quark mixing operators and include an estimate for the\nfinal error budget.",
        "positive": "Baryon-Baryon Interactions and Spin-Flavor Symmetry from Lattice Quantum\n  Chromodynamics: Lattice quantum chromodynamics is used to constrain the interactions of two\noctet baryons at the SU(3) flavor-symmetric point, with quark masses that are\nheavier than those in nature (equal to that of the physical strange quark mass\nand corresponding to a pion mass of $\\approx 806~\\tt{MeV}$). Specifically, the\nS-wave scattering phase shifts of two-baryon systems at low energies are\nobtained with the application of L\\\"uscher's formalism, mapping the energy\neigenvalues of two interacting baryons in a finite volume to the two-particle\nscattering amplitudes below the relevant inelastic thresholds. The values of\nthe leading-order low-energy scattering parameters in the irreducible\nrepresentations of SU(3) are consistent with an approximate SU(6) spin-flavor\nsymmetry in the nuclear and hypernuclear forces that is predicted in the\nlarge-$N_c$ limit of QCD. The two distinct SU(6)-invariant interactions between\ntwo baryons are constrained at this value of the quark masses, and their values\nindicate an approximate accidental SU(16) symmetry. The SU(3) irreducible\nrepresentations containing the $NN~({^1}S_0)$, $NN~({^3}S_1)$ and\n$\\frac{1}{\\sqrt{2}}(\\Xi^0n+\\Xi^-p)~({^3}S_1)$ channels unambiguously exhibit a\nsingle bound state, while the irreducible representation containing the\n$\\Sigma^+ p~({^3}S_1)$ channel exhibits a state that is consistent with either\na bound state or a scattering state close to threshold. These results are in\nagreement with the previous conclusions of the NPLQCD collaboration regarding\nthe existence of two-nucleon bound states at this value of the quark masses."
    },
    {
        "anchor": "Renormalization group improved action on anisotropic lattices: We study a block spin transformation in the SU(3) lattice gauge theory on\nanisotropic lattices to obtain Iwasaki's renormalization group improved action\nfor anisotropic cases. For the class of actions with plaquette and $1\\times2$\nrectangular terms, we determine the improvement parameters as functions of the\nanisotropy $\\xi= a_s/a_t$. We find that the program of improvement works well\nalso on anisotropic lattices. From a study of an indicator which estimates the\ndistance to the renormalized trajectory, we show that, for the range of the\nanisotropy $\\xi \\approx 1$--4, the coupling parameters previously determined\nfor isotropic lattices improve the theory considerably.",
        "positive": "The order of the phase transition in 3d U(1)+Higgs theory: We study the order of the phase transition in the 3d U(1)+Higgs theory, which\nis the Ginzburg-Landau theory of superconductivity. We confirm that for small\nscalar self-coupling the transition is of first order. For large scalar\nself-coupling the transition ceases to be of first order, and a non-vanishing\nscalar mass suggests that the transition may even be of higher than second\norder."
    },
    {
        "anchor": "Correlations of chiral condensates and quark number densities with\n  static quark sources: We investigate correlation functions of the Polyakov loop and static\nmeson/diquark systems with the chiral condensate and the quark number density\nat finite temperature. In particular the latter observable can give insight in\nthe mechanism of screening and string breaking at finite temperature. We use\nfor our analysis gauge field configurations generated in 2+1 flavor QCD with an\nimproved staggered fermion action with almost physical light quark masses and a\nphysical value of the strange quark mass on lattices with temporal extent Nt=4\nand 6.",
        "positive": "Identifying spin and parity of charmonia in flight with lattice QCD: The spectrum of charmonium resonances contains a number of unanticipated\nstates along with several conventional quark-model excitations. The hadrons of\ndifferent quantum numbers $J^P$ appear in a fairly narrow energy band, where\n$J^P$ refers to the spin-parity of a hadron at rest. This poses a challenge for\nLattice QCD studies of (coupled-channel) meson-meson scattering aimed at the\ndetermination of scattering amplitudes and resonance pole positions. A wealth\nof information for this purpose can be obtained from the lattice spectra in\nframes with nonzero total momentum. These are particularly dense since hadrons\nwith different $J^P$ contribute to any given lattice irreducible\nrepresentation. This is because $J^P$ is not a good quantum number in flight,\nand also because the continuum symmetry is reduced on the lattice. In this\npaper we address the assignment of the underlying continuum $J^P$ quantum\nnumbers to charmonia in flight using a $N_f = 2 + 1$ CLS ensemble. As a first\nstep, we apply the single-hadron approach, where only interpolating fields of\nquark-antiquark type are used. The approach follows techniques previously\napplied to the light meson spectrum by the Hadron Spectrum Collaboration. The\nresulting spectra of charmonia with assigned $J^P$ will provide valuable\ninformation for the parameterization of (resonant) amplitudes in future\ndeterminations of resonance properties with lattice QCD."
    },
    {
        "anchor": "Super Yang-Mills Theory on Lattice and the Transformation: We present a new lattice super Yang-Mills theory and its SUSY transformation.\nAfter our formulation of the model in a fundamental lattice, it is extended to\nthe whole lattice with a substructure of modulo 2.",
        "positive": "The mass of the b-quark from lattice NRQCD and lattice perturbation\n  theory: We present a determination of the b-quark mass accurate through O(\\alpha_s^2)\nin perturbation theory and including partial contributions at O(\\alpha_s^3).\nNonperturbative input comes from the calculation of the Upsilon and B_s\nenergies in lattice QCD including the effect of u, d and s sea quarks. We use\nan improved NRQCD action for the b-quark. This is combined with the heavy quark\nenergy shift in NRQCD determined using a mixed approach of high-beta simulation\nand automated lattice perturbation theory. Comparison with experiment enables\nthe quark mass to be extracted: in the MS bar scheme we find m_b(m_b) =\n4.166(43) GeV."
    },
    {
        "anchor": "Heavy Quark Effective Theory at one-loop order: An explicit example: We consider correlation functions containing the axial current of one light\nand one heavy quark in the static approximation as well as in full QCD, using\nthe lattice regularization. Up to one-loop order of perturbation theory, we\nstudy the difference between the full and the effective theory in the continuum\nlimit. In the full theory we find a term non-analytic in 1/m, revealing the\nasymptotic character of the 1/m-expansion. In general, deviations from the\nm-to-infinity limit turn out to be small and are well described by the first\nnon-trivial terms when m is a factor 2-3 above the external scale. We also\ninvestigate the mass dependence of discretization errors, and find that the\nbehaviour of the correlation functions at finite lattice spacing differs\nsignificantly from that in the continuum limit when the quark mass is large.",
        "positive": "B semileptonic decays with 2+1 dynamical quark flavors: We study semileptonic B decays, using MILC dynamical configurations with\n$N_f=2+1$. NRQCD heavy and AsqTad light quark actions are used. We obtain the\nsemileptonic form factors $f_+(q^2)$ and $f_0(q^2)$ in the chiral limit."
    },
    {
        "anchor": "The effect of sea quarks on the mass of the charm quark from Lattice QCD: We compute the mass of the charm quark using both quenched and dynamical\nlattice QCD calculations. We examine the effects of mass dependent lattice\nartifacts by comparing two different formalisms for the heavy quarks. We take\nthe continuum limit of the charm mass in quenched QCD by extrapolating from\nthree different lattice spacings. At a fixed lattice spacing, the mass of the\ncharm quark is compared between quenched QCD and dynamical QCD with a sea quark\nmass around strange. In the continuum limit of quenched QCD, we find\nm_c(m_c)=1.29(7)(13) GeV. No evidence was seen for unquenching.",
        "positive": "Effective Potential for Complex Langevin Equations: We construct an effective potential for the complex Langevin equation on a\nlattice. We show that the minimum of this effective potential gives the\nspace-time and Langevin time average of the complex Langevin field. The loop\nexpansion of the effective potential is matched with the derivative expansion\nof the associated Schwinger-Dyson equation to predict the stationary\ndistribution to which the complex Langevin equation converges."
    },
    {
        "anchor": "Studying Hadronic Structure of the Photon in Lattice QCD: We show that the matrix element of a local quark-gluon operator in the photon\nstate, $<\\gamma(k\\lambda)|\\hat O| \\gamma(k\\lambda)>$, can be calculated in\nlattice QCD. The result is generalized to other quantities involving space-like\nphotons, including the transition form factor $\\gamma\\gamma^*\\to \\pi^0$ and the\nvirtual-photon-nucleon Compton amplitude $<\\gamma^*N |\\gamma^*N>$ which can be\nused to define the generalized Drell-Hearn-Gerasimov and Bjorken sum rules.",
        "positive": "On the determination of low-energy constants for $\u0394S=1$\n  transitions: We present our preliminary results for three-point correlation functions\ninvolving the operators entering the $\\Delta{S}=1$ effective Hamiltonian with\nan active charm quark, obtained using overlap fermions in the quenched\napproximation. This is the first computation carried out for valence quark\nmasses small enough so as to permit a matching to Quenched Chiral Perturbation\nTheory in the $\\epsilon$-regime. The commonly observed large statistical\nfluctuations are tamed by means of low-mode averaging techniques, combined with\nrestrictions to individual topological sectors. We also discuss the matching of\nthe resulting hadronic matrix elements to the effective low-energy constants\nfor $\\Delta{S}=1$ transitions. This involves (a) finite-volume corrections\nwhich can be evaluated at NLO in Quenched Chiral Perturbation Theory, and (b)\nthe short-distance renormalization of the relevant four-quark operators in\ndiscretizations based on the overlap operator. We discuss perturbative\nestimates for the renormalization factors and possible strategies for their\nnon-perturbative evaluation. Our results can be used to isolate the\nlong-distance contributions to the $\\Delta I=1/2$ rule, coming from physics\neffects around the intrinsic QCD scale."
    },
    {
        "anchor": "Realistic in-medium heavy-quark potential from high statistics lattice\n  QCD simulations: We present our first results on a direct computation of the complex in-medium\nheavy quark potential from realistic lattice QCD simulations. Ensembles with\n$N_\\tau=12$ from the HotQCD and TUMQCD collaboration offer unprecedented high\nstatistics, those with $N_\\tau=16$ unprecedented time resolution, making\npossible a robust extraction of the real part from the spectral functions of\nWilson line correlators. To this end we deploy a combination of a Bayesian\nreconstruction (BR method), as well as a Pad\\'e-like approximation. We\ncorroborate findings made on less realistic lattices that ${\\rm Re}[V]$\nsmoothly transitions from a confining to a screened behavior at high\ntemperatures and its values lie close to the color singlet free energies. A\nfinite value of the ${\\rm Im}[V]$ is observed in the quark-gluon-plasma phase.",
        "positive": "Large-$N$ limit of two-dimensional Yang--Mills theory with four\n  supercharges: We study the two-dimensional Yang--Mills theory with four supercharges in the\nlarge-$N$ limit. By using thermal boundary conditions, we analyze the internal\nenergy and the distribution of scalars. We compare their behavior to the\nmaximally supersymmetric case with sixteen supercharges, which is known to\nadmit a holographic interpretation. Our lattice results for the scalar\ndistribution show no visible dependence on $N$ and the energy at strong\ncoupling appears independent of temperature."
    },
    {
        "anchor": "Double parton distributions in the nucleon from lattice simulations: We provide a first study of Mellin moments of double parton distributions\n(DPDs) in the nucleon on the lattice, where we consider several combinations of\nquark flavors and polarizations. These are accessible through two-current\ncorrelations, which can be obtained by evaluating four-point functions. In this\ncontext we consider all possible Wick contractions, where for almost all of\nthem sufficiently clear signals are obtained. In the present study, we employ\nan $n_f = 2 + 1$ CLS ensemble on a $96 \\times 32^3$ lattice with lattice\nspacing $a = 0.0856\\ \\mathrm{fm}$ and the pseudoscalar masses $m_\\pi = 355\\\n\\mathrm{MeV}$ and $m_K = 441\\ \\mathrm{MeV}$.",
        "positive": "Spectator Effects in Inclusive Decays of Beauty Hadrons: We evaluate the matrix elements of the four-quark operators which contribute\nto the lifetimes of $B$-mesons and the $\\Lambda_b$-baryon. We find that the\nspectator effects are not responsible for the discrepancy between the\ntheoretical prediction and experimental measurement of the ratio of lifetimes\n$\\tau(\\Lambda_b)/\\tau(B)$."
    },
    {
        "anchor": "Chiral phase transition in lattice QCD as a metal-insulator transition: We investigate the lattice QCD Dirac operator with staggered fermions at\ntemperatures around the chiral phase transition. We present evidence of a\nmetal-insulator transition in the low lying modes of the Dirac operator around\nthe same temperature as the chiral phase transition. This strongly suggests the\nphenomenon of Anderson localization drives the QCD vacuum to the chirally\nsymmetric phase in a way similar to a metal-insulator transition in a\ndisordered conductor. We also discuss how Anderson localization affects the\nusual phenomenological treatment of phase transitions a la Ginzburg-Landau.",
        "positive": "The crossover from first to second-order finite size scaling: A\n  numerical study Christian Borgs: We consider a particular case of the two dimensional\n  Blume-Emery-Griffiths model to study the finite-size scaling for a field\ndriven first-order phase transition with two coexisting phases not related by a\nsymmetry. For low temperatures we verify the asymptotic (large volume)\npredictions of the rigorous theory of Borgs and Kotecky, including the\npredictions concerning the so-called equal-weight versus equal-height\ncontroversy. Near the critical temperature we show that all data fit onto a\nunique curve, even when the correlation length xi becomes comparable to or\nlarger then the size of the system, provided the linear dimension L of the\nsystem is rescaled by xi."
    },
    {
        "anchor": "Topology in full QCD at high temperature: a multicanonical approach: We investigate the topological properties of $N_f = 2+1$ QCD with physical\nquark masses, at temperatures around 500 MeV. With the aim of obtaining a\nreliable sampling of topological modes in a regime where the fluctuations of\nthe topological charge $Q$ are very rare, we adopt a multicanonical approach,\nadding a bias potential to the action which enhances the probability of\nsuppressed topological sectors. This method permits to gain up to three orders\nof magnitude in computational power in the explored temperature regime. Results\nat different lattice spacings and physical spatial volumes reveal no\nsignificant finite size effects and the presence, instead, of large finite\ncut-off effects, with the topological susceptibility which decreases by 3-4\norders of magnitude while moving from $a \\simeq 0.06$ fm towards the continuum\nlimit. The continuum extrapolation is in agreeement with previous lattice\ndeterminations with smaller uncertainties but obtained based on ansatzes\njustified by several theoretical assumptions. The parameter $b_2$, related to\nthe fourth order coefficient in the Taylor expansion of the free energy density\n$f(\\theta)$, has instead a smooth continuum extrapolation which is in agreement\nwith the dilute instanton gas approximation (DIGA); moreover, a direct\nmeasurement of the relative weights of the different topological sectors gives\nan even stronger support to the validity of DIGA.",
        "positive": "Meson deformation by magnetic fields in lattice QCD: We study light meson properties in a magnetic field, focusing on a charged\npion and a charged and polarized rho meson, in quenched lattice QCD. The\ngauge-invariant density-density correlators are calculated to investigate the\ndeformation caused by the magnetic field. We find that these mesons acquire\nelongated shapes along the magnetic field. The magnitude of the deformation is\nabout 10-20 % when the strength of the magnetic field is of the order of the\nsquared unphysical pion mass."
    },
    {
        "anchor": "NLO and NNLO chiral fits for 2+1 flavor DWF ensembles: We study the use of NLO and NNLO formulae from SU(2) chiral perturbation\ntheory to fit results from the 2+1 flavor DWF QCD ensembles that have been\ngenerated by the RBC and UKQCD collaborations. These ensembles are at two\ndifferent lattice spacings, contain multiple dynamical light quark masses, and\ninclude a variety of partially quenched valence quark masses. Both NLO and\ncomplete NNLO fits well represent our data, which has m_pi in the range 220 to\n420 MeV. With our data, the NNLO fits have NLO and NNLO contributions of\nsimilar size, making the series not convergent and the extrapolation to\nphysical light quark masses imprecise. Thus, we use NLO fit results for our\npredictions of f_pi, f_K and the light quark masses.",
        "positive": "Machine Learning Estimators for Lattice QCD Observables: A novel technique using machine learning (ML) to reduce the computational\ncost of evaluating lattice quantum chromodynamics (QCD) observables is\npresented. The ML is trained on a subset of background gauge field\nconfigurations, called the labeled set, to predict an observable $O$ from the\nvalues of correlated, but less compute-intensive, observables $\\mathbf{X}$\ncalculated on the full sample. By using a second subset, also part of the\nlabeled set, we estimate the bias in the result predicted by the trained ML\nalgorithm. A reduction in the computational cost by about $7\\%-38\\%$ is\ndemonstrated for two different lattice QCD calculations using the Boosted\ndecision tree regression ML algorithm: (1) prediction of the nucleon\nthree-point correlation functions that yield isovector charges from the\ntwo-point correlation functions, and (2) prediction of the phase acquired by\nthe neutron mass when a small Charge-Parity (CP) violating interaction, the\nquark chromoelectric dipole moment interaction, is added to QCD, again from the\ntwo-point correlation functions calculated without CP violation."
    },
    {
        "anchor": "Flux simulation of the SU(3) spin model at finite chemical potential: We present a Monte Carlo simulation of an effective theory for local Polyakov\nloops at finite temperature and density. The sign problem is overcome by\nmapping the partition sum to a flux representation. We determine the phase\ndiagram of the model as a function of the temperature and the chemical\npotential.",
        "positive": "Potts Models on Feynman Diagrams: We investigate numerically and analytically Potts models on ``thin'' random\ngraphs -- generic Feynman diagrams, using the idea that such models may be\nexpressed as the N --> 1 limit of a matrix model. The thin random graphs in\nthis limit are locally tree-like, in distinction to the ``fat'' random graphs\nthat appear in the planar Feynman diagram limit, more familiar from discretized\nmodels of two dimensional gravity.\n  The interest of the thin graphs is that they give mean field theory behaviour\nfor spin models living on them without infinite range interactions or the\nboundary problems of genuine tree-like structures such as the Bethe lattice.\nq-state Potts models display a first order transition in the mean field for\nq>2, so the thin graph Potts models provide a useful test case for exploring\ndiscontinuous transitions in mean field theories in which many quantities can\nbe calculated explicitly in the saddle point approximation."
    },
    {
        "anchor": "Centre vortices are the seeds of dynamical chiral symmetry breaking: Using lattice QCD, we reveal a fundamental connection between centre vortices\nand several key features associated with dynamical chiral symmetry breaking and\nquark confinement. Calculations are performed in pure SU(3) gauge theory using\nthe chiral overlap fermion action. Starting from the original Monte Carlo gauge\nfields, a vortex identification procedure yields vortex-removed and vortex-only\nbackgrounds. We examine the static quark potential, the quark mass function,\nthe hadron spectrum, the local topological charge density, and the distribution\nof instanton-like objects on the original, vortex-removed and vortex-only\nensembles. The removal of vortices consistently results in the removal of the\ncorresponding feature associated with dynamical chiral symmetry breaking.\nRemarkably, we observe that after some smoothing, in each of these cases, the\nvortex-only degrees of freedom are able to encapsulate the pertinent features\nof the original gauge fields.",
        "positive": "Microcanonical Simulation of Complex Actions: The Wess Zumino Witten\n  Case: We present the main results of our microcanonical simulation of the Wess\nZumino Witten action functional. This action, being highly non-trivial and\ncapable of exhibiting many different phase transitions, is chosen to be\nrepresentative of general complex actions. We verify the applicability of\nmicrocanonical simulation by successfully obtaining two of the many critical\npoints of the Wess Zumino Witten action. The microcanonical algorithm has the\nadditional advantage of exhibiting critical behaviour for a small $8\\times 8$\nlattice. We also briefly discuss the subtleties that, in general, arise in\nsimulating a complex action. Our algorithm for complex actions can be extended\nto the study of\n  D-branes in the Wess Zumino Witten action."
    },
    {
        "anchor": "Nucleon resonance structure in the finite volume of lattice QCD: An approach for relating the nucleon resonances extracted from $\\pi N$\nreaction data to lattice QCD calculations has been developed by using the\nfinite-volume Hamiltonian method. Within models of $\\pi N$ reactions, bare\nstates are introduced to parametrize the intrinsic excitations of the nucleon.\nWe show that the resonance pole positions can be related to the probability\n$P_{N^*}(E)$ of finding the bare state, $N^*$, in the $\\pi N$ scattering states\nin infinite volume. We further demonstrate that the probability $P_{N^*}^V(E)$\nof finding the same bare states in the eigenfunctions of the underlying\nHamiltonian in finite volume approaches $P_{N^*}(E)$ as the volume increases.\nOur findings suggest that the comparison of $P_{N^*}(E)$ and $P_{N^*}^V(E)$ can\nbe used to examine whether the nucleon resonances extracted from the $\\pi N$\nreaction data within the dynamical models are consistent with lattice QCD\ncalculation. We also discuss the measurement of $P_{N^*}^V(E)$ directly from\nlattice QCD. The practical differences between our approach and the approach\nusing the L\\\"uscher formalism to relate LQCD calculations to the nucleon\nresonance poles embedded in the data are also discussed.",
        "positive": "Electric and Magnetic Fluxes in SU(2) Yang-Mills Theory: We measure the free energies in SU(2) of static fundamental charges and\ncenter monopoles. Dual to temporal center fluxes, the former provide a\nwell-defined (dis)order parameter for deconfinement. In contrast, the monopole\nfree energies vanish in the thermodynamic limit at all temperatures and are\nthus irrelevant for the transition."
    },
    {
        "anchor": "Up-, down-, strange-, charm-, and bottom-quark masses from four-flavor\n  lattice QCD: We calculate the up-, down-, strange-, charm-, and bottom-quark masses using\nthe MILC highly improved staggered-quark ensembles with four flavors of\ndynamical quarks. We use ensembles at six lattice spacings ranging from\n$a\\approx0.15$~fm to $0.03$~fm and with both physical and unphysical values of\nthe two light and the strange sea-quark masses. We use a new method based on\nheavy-quark effective theory (HQET) to extract quark masses from heavy-light\npseudoscalar meson masses. Combining our analysis with our separate\ndetermination of ratios of light-quark masses we present masses of the up,\ndown, strange, charm, and bottom quarks. Our results for the\n$\\overline{\\text{MS}}$-renormalized masses are $m_u(2~\\text{GeV}) =\n2.130(41)$~MeV, $m_d(2~\\text{GeV}) = 4.675(56)$~MeV, $m_s(2~\\text{GeV}) =\n92.47(69)$~MeV, $m_c(3~\\text{GeV}) = 983.7(5.6)$~MeV, and $m_c(m_c) =\n1273(10)$~MeV, with four active flavors; and $m_b(m_b) = 4195(14)$~MeV with\nfive active flavors. We also obtain ratios of quark masses $m_c/m_s =\n11.783(25)$, $m_b/m_s = 53.94(12)$, and $m_b/m_c = 4.578(8)$. The result for\n$m_c$ matches the precision of the most precise calculation to date, and the\nother masses and all quoted ratios are the most precise to date. Moreover,\nthese results are the first with a perturbative accuracy of $\\alpha_s^4$. As\nbyproducts of our method, we obtain the matrix elements of HQET operators with\ndimension 4 and 5: $\\overline{\\Lambda}_\\text{MRS}=555(31)$~MeV in the minimal\nrenormalon-subtracted (MRS) scheme, $\\mu_\\pi^2 = 0.05(22)~\\text{GeV}^2$, and\n$\\mu_G^2(m_b)=0.38(2)~\\text{GeV}^2$. The MRS scheme [Phys. Rev. D97, 034503\n(2018), arXiv:1712.04983 [hep-ph]] is the key new aspect of our method.",
        "positive": "Beautiful Baryons from Lattice QCD: We perform a lattice study of heavy baryons, containing one ($\\Lambda_b$) or\ntwo $b$-quarks ($\\Xi_b$). Using the quenched approximation we obtain for the\nmass of $\\Lambda_b$ $$ M_{\\Lambda_b}= 5.728 \\pm 0.144 \\pm 0.018 {\\rm GeV}.$$\nThe mass splitting between the $\\Lambda_b$ and the B-meson is found to increase\nby about 20\\% if the light quark mass is varied from the chiral limit to the\nstrange quark mass."
    },
    {
        "anchor": "$\u03b7$ and $\u03b7^\\prime$ masses and decay constants: We present preliminary results for the masses and decay constants of the\n$\\eta$ and $\\eta^\\prime$ mesons using CLS $N_f = 2+1$ ensembles. One of the\nmajor challenges in these calculations are the large statistical fluctuations\ndue to disconnected quark loops. We tackle these by employing a combination of\nnoise reduction techniques which are tuned to minimize the statistical error at\na fixed cost. On the analysis side we carefully assess excited states\ncontributions by using a direct fit approach.",
        "positive": "Single flavour optimisations to Hybrid Monte Carlo: It has become increasingly important to include one or more individual\nflavours of dynamical fermion in lattice QCD simulations. This is due in part\nto the advent of QCD+QED calculations, where isospin symmetry breaking means\nthat the up, down, and strange quarks must be treated separately. These\nsingle-flavour pseudofermions are typically implemented as rational\napproximations to the inverse of the fermion matrix, using the technique known\nas Rational Hybrid Monte Carlo (RHMC). Over the years, a wide range of methods\nhave been developed for accelerating simulations of two degenerate flavours of\npseudofermion, while there are comparatively fewer such techniques for\nsingle-flavour pseudofermions. Here, we investigate two different filtering\nmethods that can be applied to RHMC for simulating single-flavour\npseudofermions, namely polynomial filtering (PF-RHMC), and filtering via\ntruncations of the ordered product (tRHMC). A novel integration step-size\ntuning technique based on the characteristic scale is also introduced. Studies\nare performed on two different lattice volumes, demonstrating that one can\nachieve significant reductions in the computational cost of single-flavour\nsimulations with these filtering techniques."
    },
    {
        "anchor": "Strong coupling expansion for finite temperature Yang-Mills theory in\n  the confined phase: We perform euclidean strong coupling expansions for Yang Mills theory on the\nlattice at finite temperature. After setting up the formalism for general\nSU(N), we compute the first few terms of the series for the free energy density\nand the lowest screening mass in the case of SU(2). To next-to-leading order\nthe free energy series agrees with that of an ideal gas of glueballs. This\ndemonstrates that in the confined phase the quasi-particles indeed correspond\nto the T=0 hadron excitations, as commonly assumed in hadron resonance gas\nmodels. Our result also fixes the lower integration constant for Monte Carlo\ncalculations of the thermodynamic pressure via the integral method. In accord\nwith Monte Carlo results, we find screening masses to be nearly temperature\nindependent in the confined phase. This and the exponential smallness of the\npressure can be understood as genuine strong coupling effects. Finally, we\nanalyse Pade approximants to estimate the critical couplings of the phase\ntransition, which for our short series are only ~25% accurate. However, up to\nthese couplings the equation of state agrees quantitatively with numerical\nresults on N_t=1-4 lattices.",
        "positive": "Quasi-PDFs from Twisted mass fermions at the physical point: We present results for the flavor non-singlet u-d parton distribution\nfunctions within the nucleon using the quasi-PDF approach. The lattice\ncalculation is performed by employing the twisted mass formulation and two\ngauge ensembles, having $N_f = 2$ and $N_f = 2 + 1 + 1$ dynamical fermions with\nmasses tuned to their physical value. For the $N_f = 2$ physical point\nensemble, the unpolarized, helicity and transversity distributions are computed\nfor three values of the nucleon momentum, namely [6, 8, 10]$\\pi/L$\ncorresponding to [0.83,1.11,1.38] GeV. Upon renormalization, we find that, as\nthe nucleon momentum increases, the lattice results approach the\nphenomenological distributions resulting from analyses of deep inelastic\nscattering data, opening a promising path for a direct evaluation of parton\ndistributions from the QCD Lagrangian. For the $N_f = 2 + 1 + 1$ physical point\nensemble, we present preliminary results for the unpolarized distribution\nextracted from a nucleon boosted by $8\\pi/L$ or 0.97 GeV."
    },
    {
        "anchor": "Calculation of the axial charge in the epsilon and epsilon' regimes of\n  HBChPT: The axial charge g_A is calculated in the epsilon regime of Heavy Baryon\nChiral Perturbation Theory to order epsilon^3. To perform this calculation, we\ndevelop a technique to compute baryon properties in the epsilon regime of\nChiral Perturbation Theory. This technique includes contributions from pion\nzero momentum modes and can be used at arbitrary order, diagram by diagram, in\nthe $\\epsilon$ regime to calculate any matrix element. Also, a calculation of\ng_A in the epsilon' regime to order epsilon'^3 is performed. A discussion of\nthe domain of applicability for both the epsilon and epsilon' regimes is also\nincluded.",
        "positive": "The continuum limit of the lattice Gribov problem, and a solution based\n  on Hodge decomposition: We study gauge fixing via the standard local extremization algorithm for\n2-dimensional $U(1)$. On a lattice with spherical topology $S^2$ where all\ncopies are lattice artifacts, we find that the number of these 'Gribov' copies\ndiverges in the continuum limit. On a torus, we show that lattice artifacts can\nlead to the wrong evaluation of the gauge-invariant correlation length, when\nmeasured via a gauge-fixed procedure; this bias does not disappear in the\ncontinuum limit. We then present a new global approach, based on Hodge\ndecomposition of the gauge field, which produces a unique smooth field in\nLandau gauge, and is economically powered by the FFT. We also discuss the use\nof this method for examining topological objects, and its extensions to\nnon-abelian gauge fields."
    },
    {
        "anchor": "Pathological Behavior of Renormalization-Group Maps at High Fields and\n  Above the Transition Temperature: We show that decimation transformations applied to high-$q$ Potts models\nresult in non-Gibbsian measures even for temperatures higher than the\ntransition temperature. We also show that majority transformations applied to\nthe Ising model in a very strong field at low temperatures produce non-Gibbsian\nmeasures. This shows that pathological behavior of renormalization-group\ntransformations is even more widespread than previous examples already\nsuggested.",
        "positive": "Wave functions for Hamiltonian Lattice Gauge Theory: We study four dimensional SU(2) lattice gauge theory in the Hamiltonian\nformalism by Green's Function Monte Carlo methods. A trial ground state wave\nfunction is introduced to improve the configuration sampling and we discuss the\ninterplay between its complexity and the simulation systematic errors. As a\ncase study, we compare the leading strong coupling approximation and an\nimproved 4 parameters wave function with 1X1 and 1X2 plaquette terms. Our\nnumerical results favors the second option."
    },
    {
        "anchor": "Lattice QCD calculation of the ${{B}_{(s)}\\to D_{(s)}^{*}\\ell\u03bd}$\n  form factors at zero recoil and implications for ${|V_{cb}|}$: We present results of a lattice QCD calculation of $B\\to D^*$ and $B_s\\to\nD_s^*$ axial vector matrix elements with both states at rest. These zero recoil\nmatrix elements provide the normalization necessary to infer a value for the\nCKM matrix element $|V_{cb}|$ from experimental measurements of $\\bar{B}^0\\to\nD^{*+}\\ell^-\\bar{\\nu}$ and $\\bar{B}^0_s\\to D_s^{*+}\\ell^-\\bar{\\nu}$ decay.\nResults are derived from correlation functions computed with highly improved\nstaggered quarks (HISQ) for light, strange, and charm quark propagators, and\nnonrelativistic QCD for the bottom quark propagator. The calculation of\ncorrelation functions employs MILC Collaboration ensembles over a range of\nthree lattice spacings. These gauge field configurations include sea quark\neffects of charm, strange, and equal-mass up and down quarks. We use ensembles\nwith physically light up and down quarks, as well as heavier values. Our main\nresults are $\\mathcal{F}^{B\\to D^*}(1)= 0.895\\pm\n0.010_{\\mathrm{stat}}\\pm{{0.024}_{\\mathrm{sys}}}$ and $\\mathcal{F}^{B_s\\to\nD_s^*}(1)= 0.883\\pm 0.010_{\\mathrm{stat}}\\pm{0.028_{\\mathrm{sys}}}$. We discuss\nthe consequences for $|V_{cb}|$ in light of recent investigations into the\nextrapolation of experimental data to zero recoil.",
        "positive": "Complex Heavy-Quark Potential at Finite Temperature from Lattice QCD: We calculate for the first time the complex potential between a heavy quark\nand antiquark at finite temperature across the deconfinement transition in\nlattice QCD. The real and imaginary part of the potential at each separation\ndistance $r$ is obtained from the spectral function of the thermal Wilson loop.\nWe confirm the existence of an imaginary part above the critical temperature\n$T_C$, which grows as a function of $r$ and underscores the importance of\ncollisions with the gluonic environment for the melting of heavy quarkonia in\nthe quark-gluon-plasma."
    },
    {
        "anchor": "Lattice gauge theory for Haldane conjecture and central-branch Wilson\n  fermion: We develop the $(1+1)$d lattice $U(1)$ gauge theory in order to define\n$2$-flavor massless Schwinger model, and discuss its connection with Haldane\nconjecture. We propose to use the central-branch Wilson fermion, which is\ndefined by relating the mass, $m$, and the Wilson parameter, $r$, as $m+2r=0$.\nThis setup gives two massless Dirac fermions in the continuum limit, and it\nturns out that no fine-tuning of $m$ is required because the extra $U(1)$\nsymmetry at the central branch, $U(1)_{\\bar{V}}$, prohibits the additive mass\nrenormalization. Moreover, we show that Dirac determinant is positive\nsemi-definite and this formulation is free from the sign problem, so the Monte\nCarlo simulation of the path integral is possible. By identifying the symmetry\nat low energy, we show that this lattice model has the mixed 't Hooft anomaly\nbetween $U(1)_{\\bar{V}}$, lattice translation, and lattice rotation. We discuss\nits relation to the anomaly of half-integer anti-ferromagnetic spin chains, so\nour lattice gauge theory is suitable for numerical simulation of Haldane\nconjecture. Furthermore, it gives new and strict understanding on parity-broken\nphase (Aoki phase) of $2$d Wilson fermion.",
        "positive": "Manifestations of the axial anomaly in finite temperature QCD: We compute the flavor singlet meson correlators and screening masses in\nquenched and $N_f=2$ QCD at $N_t=8$. The consequences of our results for the\nrealization of the $U_A(1)$ symmetry at finite T are discussed and an\ninterpretation of our measurements in terms of the behaviour of the low lying\nfermionic modes is proposed."
    },
    {
        "anchor": "Screening Masses of Hot SU(2) Gauge Theory from the 3d Adjoint Higgs\n  Model: We study the Landau gauge propagators of the lattice SU(2) 3d adjoint Higgs\nmodel, considered as an effective theory of high temperature 4d SU(2) gauge\ntheory. From the long distance behaviour of the propagators we extract the\nscreening masses. The propagators are studied both in the symmetric and the\nbroken phases of the 3d Higgs model. It is shown that the pole masses extracted\nfrom the propagators in the symmetric phase agree well with the screening\nmasses obtained recently in finite temperature SU(2) theory, while propagators\nmeasured in the broken phase show quite a different behaviour. This suggest\nthat the symmetric phase of the 3d model corresponds to the deconfined phase of\nthe 4d SU(2) gauge theory. The relation of the propagator masses to the masses\nextracted from gauge invariant correlators and the mass gap of pure 3d SU(2)\ngauge theory is also discussed.",
        "positive": "N=1 Super Yang-Mills on the Lattice in the Strong Coupling Limit: We study the N=1 supersymmetric SU(N) Yang-Mills theory on the lattice at\nstrong coupling. We analyse and discuss the recent results obtained at strong\ncoupling and large N for the mesonic and fermionic propagators and spectrum."
    },
    {
        "anchor": "The dependence of observables on action parameters: Many applications in Lattice field theory require to determine the Taylor\nseries of observables with respect to action parameters. A primary example is\nthe determination of electromagnetic corrections to hadronic processes. We show\ntwo possible solutions to this general problem, one based on reweigting, that\ncan be considered a generalization of the RM123 method. The other based on the\nideas of Numerical Stochastic Perturbation Theory (NSPT) in the Hamiltonian\nformulation. We show that 1) the NSPT-based approach shows a much reduced\nvariance in the determination of the Taylor coefficients, and 2) That both\napproaches are related by a change of variables. Numerical results are shown\nfor the case of $\\lambda-\\phi^4$ in 4 dimensions, but we expect these\nobservations to be general. We conclude by commenting on the possible use of\nMachine Learning techniques to find similar change of variables that can\npotentially reduce the variance in Taylor coefficients.",
        "positive": "Light quark masses using domain wall fermions: We compute the one-loop self-energy correction to the massive domain wall\nquark propagator. Combining this calculation with simulations at several gauge\ncouplings, we estimate the strange quark mass in the continuum limit. The\nperturbative one-loop mass renormalization is comparable to that for Wilson\nquarks and considerably smaller than that for Kogut-Susskind quarks. Also,\nscaling violations appear mild in comparison to other errors at present. Given\ntheir good chiral behavior and these features, domain wall quarks are\nattractive for evaluating the light quark masses. Our preliminary quenched\nresult is m_s(2 GeV) = 82(15) MeV in the ${\\bar{MS}}$ scheme."
    },
    {
        "anchor": "Moments of nucleon generalized parton distributions from lattice QCD: We present results on the lower moments of the nucleon generalized parton\ndistri butions within lattice QCD using two dynamical flavors of degenerate\ntwisted mass fermions. Our simulations are performed on lattices with three\ndifferent values of the lattice spacings, namely $a=0.089$ fm, $a=0.070$ fm and\n$a=0.056$ fm, allowing the investigation of cut-off effects. The volume\ndependence is examined using simulations on two lattices of spatial length\n$L=2.1$ fm and $L=2.8$ fm. The simulations span pion masses in the range of\n260-470 MeV. Our results are renormalized non-perturbatively and the values are\ngiven in the $\\bar{\\rm MS}$ scheme at a scale $ \\mu=2$ GeV. They are chirally\nextrapolated to the physical point in order to compare with experiment. The\nconsequences of these results on the spin carried by the quarks in the nucleon\nare investigated.",
        "positive": "Critical behavior of the compact 3d U(1) theory in the limit of zero\n  spatial coupling: Critical properties of the compact three-dimensional U(1) lattice gauge\ntheory are explored at finite temperatures on an asymmetric lattice. For\nvanishing value of the spatial gauge coupling one obtains an effective\ntwo-dimensional spin model which describes the interaction between Polyakov\nloops. We study numerically the effective spin model for N_t=1,4,8 on lattices\nwith spatial extension ranging from L=64 to L=256. Our results indicate that\nthe finite-temperature U(1) lattice gauge theory belongs to the universality\nclass of the two-dimensional XY model, thus supporting the Svetitsky-Yaffe\nconjecture."
    },
    {
        "anchor": "Systematic effects of the quenched approximation on the strong penguin\n  contribution to epsilon'/epsilon: We discuss the implementation and properties of the quenched approximation in\nthe calculation of the left-right, strong penguin contributions (i.e. Q_6) to\nepsilon'/epsilon. The coefficient of the new chiral logarithm, discovered by\nGolterman and Pallante, which appears at leading order in quenched chiral\nperturbation theory is evaluated using both the method proposed by those\nauthors and by an improved approach which is free of power divergent\ncorrections. The result implies a large quenching artifact in the contribution\nof Q_6 to epsilon'/epsilon. This failure of the quenched approximation affects\nonly the strong penguin operators and so does not affect the Q_8 contribution\nto epsilon'/epsilon nor Re A_0, Re A_2 and thus the Delta I=1/2 rule at tree\nlevel in chiral perturbation theory.",
        "positive": "Matrix product states for Hamiltonian lattice gauge theories: Over the last decade tensor network states (TNS) have emerged as a powerful\ntool for the study of quantum many body systems. The matrix product states\n(MPS) are one particular case of TNS and are used for the simulation of 1+1\ndimensional systems. In [1] we considered the MPS formalism for the simulation\nof the Hamiltonian lattice gauge formulation of 1+1 dimensional one flavor\nquantum electrodynamics, also known as the massive Schwinger model. We deduced\nthe ground state and lowest lying excitations. Furthermore, we performed a full\nquantum real-time simulation for a quench with a uniform background electric\nfield. In this proceeding we continue our work on the Schwinger model. We\ndemonstrate the advantage of working with gauge invariant MPS by comparing with\nMPS simulations on the full Hilbert space, that includes numerous non-physical\ngauge variant states. Furthermore, we compute the chiral condensate and recover\nthe predicted UV-divergent behavior."
    },
    {
        "anchor": "QCD on the Cell Broadband Engine: We evaluate IBM's Enhanced Cell Broadband Engine (BE) as a possible building\nblock of a new generation of lattice QCD machines. The Enhanced Cell BE will\nprovide full support of double-precision floating-point arithmetics, including\nIEEE-compliant rounding. We have developed a performance model and applied it\nto relevant lattice QCD kernels. The performance estimates are supported by\nmicro- and application-benchmarks that have been obtained on currently\navailable Cell BE-based computers, such as IBM QS20 blades and PlayStation 3.\nThe results are encouraging and show that this processor is an interesting\noption for lattice QCD applications. For a massively parallel machine on the\nbasis of the Cell BE, an application-optimized network needs to be developed.",
        "positive": "Disconnected Loop Subtraction Methods in Lattice QCD: Lattice QCD calculations of disconnected quark loop operators are extremely\ncomputer time-consuming to evaluate. To compute these diagrams using lattice\ntechniques, one generally uses stochastic noise methods. These employ a\nrandomly generated set of noise vectors to project out physical signals. In\norder to strengthen the signal in these calculations, various noise subtraction\ntechniques may be employed. In addition to the standard method of perturbative\nsubtraction, one may also employ matrix deflation techniques using the GMRES-DR\nand MINRES-DR algorithms as well as polynomial subtraction techniques to reduce\nstatistical uncertainty. Our matrix deflation methods play two roles: they both\nspeed up the solution of the linear equations as well as decrease numerical\nnoise. We show how to combine deflation with either perturbative and polynomial\nmethods to produce extremely powerful noise suppression algorithms. We use a\nvariety of lattices to study the effects. In order to set a benchmark, we first\nuse the Wilson matrix in the quenched approximation. We see strong low\neigenmode dominance at kappa critical ($\\kappa_{crit}$) in the variance of the\nvector and scalar operators. We also use MILC dynamic lattices, where we\nobserve deflation subtraction results consistent with the effectiveness seen in\nthe quenched data."
    },
    {
        "anchor": "Nucleon axial charge in domain-wall QCD with physical mass: Nucleon isovector vector, $g_V$, and axialvector, $g_A$, charges calculated\non a 2+1-flavor dynamical domain-wall-fermions (DWF) ensemble at physical mass\njointly generated by RIKEN-BNL-Columbia (RBC) and UKQCD Collaborations with\nlattice cut off of 1.730(4) GeV, are reported with about a percent statistical\nerrors, along with isovector ``scalar,'' $g_S$, and ``tensor charges,'' $g_T$,\nwith larger statistical errors. Nucleon mass is estimated as 947(6) MeV. A few\nstandard-deviation systematics is seen in the vector charge, likely from\n$O(a^2)$ discretization error through small excited-state contamination. The\naxialvector charge is found with a few to several standard-deviation systematic\ndeficit, depending on calculation methods, in comparison with the experiment.\nNucleon signal is likely lost as early as 10 lattice units or about 1.1 fm in\ntime from the source.",
        "positive": "Neutron Electric Dipole Moment on the Lattice: For the neutron to have an electric dipole moment (EDM), the theory of nature\nmust have T, or equivalently CP, violation. Neutron EDM is a very good probe of\nnovel CP violation in beyond the standard model physics. To leverage the\nconnection between measured neutron EDM and novel mechanism of CP violation,\none requires the calculation of matrix elements for CP violating operators, for\nwhich lattice QCD provides a first principle method. In this paper, we review\nthe status of recent lattice QCD calculations of the contributions of the QCD\n$\\Theta$-term, the quark EDM term, and the quark chromo-EDM term to the neutron\nEDM."
    },
    {
        "anchor": "A formulation of domain wall fermions in the Schroedinger functional: We present a formulation of domain wall fermions in the Schroedinger\nfunctional by following the universality argument given by L\\\"uscher. To check\nwhether the formulation works, we examine the lowest eigenmode of the free\ndomain wall fermion operator. We confirm that the theory belongs to a correct\nuniversality class and that the eigenvector is localized near the boundaries of\nthe fifth dimension. We also investigate the chiral symmetry breaking structure\nof the four dimentional effective operator. We observe that the bulk chiral\nsymmetry breaking disappears for a large fifth dimensional size, while the\nbreaking originated by the boundary effects persists and exponetially decays\naway from the time boundaries.",
        "positive": "Test of the Polyakov Loop Model: We discuss the two point functions for the real and imaginary parts of the\nPolyakov loop in a pure SU(3) gauge theory. The behavior of these correlation\nfunctions in the Polyakov Loop Model is markedly different from that in\nperturbation theory."
    },
    {
        "anchor": "News from bottomonium spectral functions in thermal QCD: New results on bottomonium at nonzero temperature are presented, using the\nFASTSUM Generation 2L ensembles. Preliminary results for spectral function\nreconstruction using Kernel Ridge Regression, a machine learning technique, are\nshown as well and compared to results from the Maximum Entropy Method.",
        "positive": "Volume reduction in large-N lattice gauge theories [with adjoint\n  fermions]: This work covers volume reduction in quantum field theories on a lattice at\nlarge $N$ (number of colors), as first described by Eguchi and Kawai in 1982.\nThe volume reduction (or volume independence) means that the theory defined on\nan arbitrarily small lattice is equivalent in the large-$N$ limit to the theory\non an infinite lattice with the same bare parameters. We analyze the volume\nreduction by means of Monte Carlo simulations using the lattice model on a\nsingle site (or a small fixed number of sites) with Wilson fermions in the\nadjoint representation, using $N$ up to 60. Most of the results focus on two\nflavours of Dirac fermions and the single fermionic flavour is also discussed\nwhere there is a significant difference of behaviour. We find that the\n$(Z_N)^4$ center symmetry, necessary for the realization of volume reduction,\nis unbroken in the reduced model for a large range of parameters and, in\nparticular, that the maximum admissible value of the adjoint fermion mass is\nnon-zero in the large-$N$ limit. We calculate physical quantities, such as the\nplaquette, the static quark potential and the eigenvalues of the Dirac\noperator. We analyze the finite-$N$ corrections and consider the practicality\nof volume-reduced models in supplementing the large-volume calculations."
    },
    {
        "anchor": "Comparison of Monte Carlo Results for the 3D Ising Interface Tension and\n  Interface Energy with (Extrapolated) Series Expansions: We compare Monte Carlo results for the interface tension and interface energy\nof the 3-dimensional Ising model with Pad\\'e and inhomogeneous differential\napproximants of the low temperature series that was recently extended by Arisue\nto $17^{\\rm th}$ order in $u=\\exp(-4\\beta)$. The series is expected to suffer\nfrom the roughening singularity at $u\\approx 0.196$. The comparison with the\nMonte Carlo data shows that the Pad\\'e and inhomogeneous differential\napproximants fail to improve the truncated series result of the interface\ntension and the interface energy in the region around the roughening\ntransition. The Monte Carlo data show that the specific heat displays a peak in\nthe smooth phase. Neither the truncated series nor the Pad\\'e approximants find\nthis peak. We also compare Monte Carlo data for the energy of the ASOS model\nwith the corresponding low temperature series that we extended to order\n$u^{12}$.",
        "positive": "How good is the quenched approximation of QCD?: The quenched approximation for QCD is, at present and in the foreseeable\nfuture, unavoidable in lattice calculations with realistic choices of the\nlattice spacing, volume and quark masses. In this talk, I review an analytic\nstudy of the effects of quenching based on chiral perturbation theory. Quenched\nchiral perturbation theory leads to quantitative insight on the difference\nbetween quenched and unquenched QCD, and reveals clearly some of the diseases\nwhich are expected to plague quenched QCD. Uses jnl.tex and epsf.tex for figure\n3. Figures 1 and 2 not included, sorry. Available as hardcopy on request."
    },
    {
        "anchor": "Infrared behavior and infinite-volume limit of gluon and ghost\n  propagators in Yang-Mills theories: Lattice studies of the infrared behavior of gluon and ghost propagators are a\nkey probe of confinement scenarios in Yang-Mills theories. However,\nfinite-volume effects become an important issue as the infrared limit is\napproached. By considering general quantities -- namely an associated\nsusceptibility in the gluon case and properties of the lowest-lying eigenmode\nof the Faddeev-Popov matrix in the ghost case -- one can derive rigorous upper\nand lower bounds for the propagators. The bounds allow a better control over\nthe extrapolation of lattice results to the infinite-volume limit. In the case\nof the gluon propagator, an intuitive statistical argument suggests a precise\nvolume dependence for the bounds. This dependence is nicely confirmed by the\nlattice data, leading to a finite gluon propagator at zero momentum. At the\nsame time, an enhancement of the ghost propagator in the infrared limit seems\nunlikely. Our analysis is applied to the case of Landau gauge and SU(2) gauge\ngroup, using the largest lattice sizes to date.",
        "positive": "Supersymmetric gauge theories on the lattice: Pfaffian phases and the\n  Neuberger 0/0 problem: Recently a class of supersymmetric gauge theories have been successfully\nimplemented on the lattice. However, there has been an ongoing debate on\nwhether lattice versions of some of these theories suffer from a sign problem,\nwith independent simulations for the ${\\cal N} = (2, 2)$ supersymmetric\nYang-Mills theories in two dimensions yielding seemingly contradictory results.\nHere, we address this issue from an interesting theoretical point of view. We\nconjecture that the sign problem observed in some of the simulations is related\nto the so called Neuberger 0/0 problem, which arises in ordinary\nnon-supersymmetric lattice gauge theories, and prevents the realization of\nBecchi-Rouet-Stora-Tyutin symmetry on the lattice. After discussing why we\nexpect a sign problem in certain classes of supersymmetric lattice gauge\ntheories far from the continuum limit, we argue that these problems can be\nevaded by use of a non-compact parametrization of the gauge link fields."
    },
    {
        "anchor": "Confining strings in SU(N) gauge theories: We calculate the string tensions of $k$-strings in SU($N$) gauge theories in\nboth 3 and 4 dimensions. In D=3+1, we find that the ratio of the $k=2$ string\ntension to the $k = 1$ fundamental string tension is consistent, at the $2\n\\sigma$ level, with both the M(-theory)QCD-inspired conjecture and with\n`Casimir scaling'. In D=2+1 we see a definite deviation from the MQCD formula,\nas well as a much smaller but still significant deviation from Casimir scaling.\nWe find that in both D=2+1 and D=3+1 the high temperature spatial $k$-string\ntensions also satisfy approximate Casimir scaling. We point out that\napproximate Casimir scaling arises naturally if the cross-section of the flux\ntube is nearly independent of the flux carried, and that this will occur in an\neffective dual superconducting description, if we are in the deep-London limit.\nWe estimate, numerically, the intrinsic width of $k$-strings in D=2+1 and\nindeed find little variation with $k$. In addition to the stable $k$-strings we\ninvestigate some ofthe unstable strings, finding in D=2+1 that they satisfy\n(approximate) Casimir scaling. We also investigate the basic assumption that\nconfining flux tubes are described by an effective string theory at large\ndistances. We estimate the coefficient of the universal L\\\"uscher correction\nfrom periodic strings that are longer than 1 fermi, and find $c_L=0.98(4)$ in\nD=3+1 and $c_L=0.558(19)$ in D=2+1. These values are within $2 \\sigma$ of the\nsimple bosonic string values and are inconsistent with other simple effective\nstring theories.",
        "positive": "Phase transition in finite density and temperature lattice QCD: We investigate the behavior of the chiral condensate in lattice QCD at finite\ntemperature and finite chemical potential. The study was done using two flavors\nof light quarks and with a series of $\\beta$ and $ma$ at the lattice size\n$24\\times12^{2}\\times6$. The calculation was done in the Taylar expansion\nformalism. We are able to calculate the first and second order derivatives of\n$\\langle\\bar{\\psi}\\psi\\rangle$ in both isoscalar and isovector channels. With\nthe first derivatives being small, we find that the second derivatives are\nsizable close to the phase transition and the magnitude of $\\bar{\\psi}\\psi$\ndecreases under the influence of finite chemical potential in both channels."
    },
    {
        "anchor": "Computing the lowest eigenvalues of the Fermion matrix by subspace\n  iterations: Subspace iterations are used to minimise a generalised Ritz functional of a\nlarge, sparse Hermitean matrix. In this way, the lowest $m$ eigenvalues are\ndetermined. Tests with $1 \\leq m \\leq 32$ demonstrate that the computational\ncost (no. of matrix multiplies) does not increase substantially with $m$. This\nimplies that, as compared to the case of a $m=1$, the additional eigenvalues\nare obtained for free.",
        "positive": "I=3/2 nucleon-pion scattering and the Delta(1232) resonance on 2+1\n  flavor CLS ensembles using the stochastic LapH method: Calculations of the elastic $I=\\frac{3}{2}$ nucleon-pion scattering phase\nshifts on two lattice QCD ensembles with $m_\\pi=200\\mathrm{MeV}$ and\n$280\\mathrm{MeV}$ are presented. The ensembles both employ $N_\\mathrm{f} = 2+1$\nWilson clover fermions. We determine the $\\Delta(1232)$ resonance parameters\nfrom a finite volume scattering analysis. In one study the single partial wave\nsimplification is employed to compute the $p$-wave amplitude while in the other\nwe treat the partial wave mixing between $s$- and $p$-wave contributions.\nFitting our data to a Breit-Wigner resonance model we find $m_\\Delta/m_\\pi =\n7.13(9)$ and $4.75(5)$ on the two ensembles respectively, showing that for a\nlighter quark mass the resonance mass moves from near the $N\\pi$ threshold to\nnear the $N\\pi\\pi$ threshold, in agreement with experiment."
    },
    {
        "anchor": "Exploring distillation at the SU(3) flavour symmetric point: In these proceedings we present an exact distillation setup with stabilised\nWilson fermions at the SU(3) flavour symmetric point utilising the flexibility\nof the Grid and Hadrons software libraries. This work is a stepping stone\ntowards a non-perturbative investigation of hadronic D-decays, for which one\nneeds to control the multi-hadron final states. As a first step we study\ntwo-to-two s-wave scattering of pseudoscalar mesons. In particular we examine\nthe reliability of the extraction of finite-volume energies as a function of\nthe number of eigenvectors of the gauge-covariant Laplacian entering our\ndistillation setup.",
        "positive": "Accurate hadron spectroscopy on blocked configurations by\n  tadpole-renormalized, clover-improved Wilson quark action: We compare the quenched hadron spectrum on blocked and unblocked lattices for\nthe Wilson quark action, the clover action and the tadpole-improved clover\naction. The latter gives a spectrum markedly closer to the original one, even\nthough the cutoff is 1/a ~ 500 Mev."
    },
    {
        "anchor": "Interaction potential between heavy $Q \\bar{Q}$ in color octet\n  configuration in QGP: We investigate the interaction between a heavy quark-antiquark pair in color\noctet configuration in gluon plasma. We calculate nonperturbatively an\neffective thermal potential for such a pair through the study of the\ncorrelation function of a hybrid state with $Q \\bar{Q}$ octet and an adjoint\ngluon source in the static limit. We discuss the extraction of an octet\npotential, and present results for the effective thermal potential between\noctet $Q \\bar{Q}$ pair in gluon plasma for moderately high temperatures\n$\\lesssim 2 T_c$. The implications of our result are discussed.",
        "positive": "Fits of $SU(3)$ $N_f=8$ data to dilaton-pion effective field theory: We report on fits of the $SU(3)$ $N_f=8$ LSD spectral data to chiral\nperturbation theory with a dilatonic meson. These fits confirm that current\nsimulations are in the \"large-mass\" regime, with approximate hyperscaling as\nthe leading mass dependence. We find that the leading-order effective field\ntheory describes the data well. In particular, the effective field theory\nallows us to understand the staggered taste splitting, explaining the pattern\nobserved in the LSD data, which looks different from QCD."
    },
    {
        "anchor": "Hadronic property at finite density: We report on three topics on finite density simulations: (i) the derivative\nmethod for hadronic quantities, (ii) phase fluctuations in the vicinity of the\ncritical temperature and (iii) the density of states method at finite isospin\ndensity.",
        "positive": "Determination of the Delta resonance width from lattice QCD: A method suitable for extracting resonance parameters of unstable baryons in\nlattice QCD is examined. The method is applied to the strong decay of the Delta\nto a pion-nucleon state, extracting the pi-N - Delta coupling constant and\nDelta decay width."
    },
    {
        "anchor": "Two-Dimensional Dynamical Triangulation using the Grand-canonical\n  Ensemble: The string susceptibility exponents of dynamically triangulated two\ndimensional surfaces with sphere and torus topology were calculated using the\ngrand-canonical Monte Carlo method. We also simulated the model coupled to\nd-Ising spins (d=1,2,3,5).",
        "positive": "Baryon Number, Strangeness and Electric Charge Fluctuations in QCD at\n  High Temperature: We analyze baryon number, strangeness and electric charge fluctuations as\nwell as their correlations in QCD at high temperature. We present results\nobtained from lattice calculations performed with an improved staggered fermion\naction (p4-action) at two values of the lattice cut-off with almost physical up\nand down quark masses and a physical value for the strange quark mass. We\ncompare these results, with an ideal quark gas at high temperature and a hadron\nresonance gas model at low temperature. We find that fluctuations and\ncorrelations are well described by the former already for temperatures about\n1.5 times the transition temperature. At low temperature qualitative features\nof the lattice results are quite well described by a hadron resonance gas\nmodel. Higher order cumulants, which become increasingly sensitive to the light\npions, however show deviations from a resonance gas in the vicinity of the\ntransition temperature."
    },
    {
        "anchor": "Passing through the `chiral limit' in quenched QCD with Wilson fermions: We investigate the limit of vanishing quark mass in quenched lattice QCD with\nunimproved Wilson fermions at $\\beta=6.0$. Exploiting the correlations of\npropagators at different time slices we extract pion masses extremely close to\nthe `chiral limit', despite the presence of `exceptional configurations'. With\nthis at hand, the existence of quenched chiral logarithms can be demonstrated,\nprovided, finite size effects are small. With reference to the phase diagram\nproposed by Aoki also the range $\\kappa > \\kappa_c$ is investigated. The width\nof a potential parity-flavor violating phase can, if at all, hardly be\nresolved.",
        "positive": "Screening of sources in higher representations of SU(N) gauge theories\n  at zero and finite temperature: Completion of the Svetitsky-Yaffe conjecture in some (2+1) dimensional SU(N)\ngauge theories allows mapping Polyakov loops in higher representations of the\ngauge group into suitable conformal operators of the corresponding 2D CFT. As a\nconsequence, the critical exponents of the correlators of these Polyakov loops\nare determined. The functional form of these correlators suggests a general\nAnsatz to describe the large-distance screening of higher-representation\nsources at zero temperature in any space-time dimension. A generalised Wilson\nloop in which along part of its trajectory a source is converted in a gauge\ninvariant way into higher representations with same N-ality could be used to\nestimate the decay scale of the unstable strings"
    },
    {
        "anchor": "The Gluon Propagator in Momentum Space: We give preliminary numerical results for the gluon propagator evaluated both\nin coordinate and momentum space on a 16^3X40 quenched lattice at beta=6.0. Our\nfindings are compared with earlier results in the literature at zero momentum.\nIn addition, by considering nonzero momenta we attempt to extract the form of\nthe propagator and compare it to continuum predictions formulated by Gribov and\nothers. latex, file espcrc2.sty needed (appended at the end: search for\nespcrc2.sty).",
        "positive": "Large fluctuations in NSPT computations: a lesson from $O(N)$ non-linear\n  sigma models: In the last three decades, Numerical Stochastic Perturbation Theory (NSPT)\nhas proven to be an excellent tool for calculating perturbative expansions in\ntheories such as Lattice QCD, for which standard, diagrammatic perturbation\ntheory is known to be cumbersome. Despite the significant success of this\nstochastic method and the improvements made in recent years, NSPT apparently\ncannot be successfully implemented in low-dimensional models due to the\nemergence of huge statistical fluctuations: as the perturbative order gets\nhigher, the signal to noise ratio is simply not good enough. This does not come\nas a surprise, but on very general grounds, one would expect that the larger\nthe number of degrees of freedom, the less severe the fluctuations will be. By\nsimulating $2D$ $O(N)$ non-linear sigma models for different values of $N$, we\nshow that indeed the fluctuations are tamed in the large $N$ limit, meeting our\nexpectations. Having established this, we conclude discussing interesting\napplications of NSPT in the context of these theories."
    },
    {
        "anchor": "Continuum Limit of Overlap Valence Quarks on a Twisted Mass Sea: We study a lattice QCD mixed action with overlap valence quarks on two\nflavours of Wilson maximally twisted mass sea quarks. Employing three different\nmatching conditions to relate both actions to each other, we investigate the\ncontinuum limit by using three values of the lattice spacing ranging from 0.05\nfm to 0.08 fm. A particular emphasis is put on the effect on physical\nobservables of the topological zero modes appearing in the valence overlap\noperator. We estimate the region of parameter space where the contribution from\nthese zero modes is sufficiently small such that their effects can be safely\ncontrolled and a restoration of unitarity of the mixed action in the continuum\nlimit is reached.",
        "positive": "Quantum Computing for the Wess-Zumino Model: Future quantum computers will enable novel sign-problem-free studies of\ndynamical phenomena in non-perturbative quantum field theories, including\nreal-time evolution and spontaneous supersymmetry breaking. We are\ninvestigating applications of quantum computing to low-dimensional\nsupersymmetric lattice systems that can serve as testbeds for existing and\nnear-future quantum devices. Here we present initial results for the\n$\\mathcal{N} = 1$ Wess--Zumino model in 1+1 dimensions, building on our prior\nanalyses of 0+1-dimensional supersymmetric quantum mechanics. In addition to\nexploring supersymmetry breaking using the variational quantum eigensolver, we\nconsider the prospects for real-time evolution."
    },
    {
        "anchor": "Vector and scalar charmonium resonances with lattice QCD: We perform an exploratory lattice QCD simulation of $D \\bar D$ scattering,\naimed at determining the masses as well as the decay widths of charmonium\nresonances above open charm threshold. Neglecting coupling to other channels,\nthe resulting phase shift for $D \\bar D$ scattering in p-wave yields the\nwell-known vector resonance $\\psi(3770)$. For $m_\\pi = 156$ MeV, the extracted\nresonance mass and the decay width agree with experiment within large\nstatistical uncertainty. The scalar charmonium resonances present a puzzle,\nsince only the ground state $\\chi_{c0}(1P)$ is well understood, while there is\nno commonly accepted candidate for its first excitation. We simulate $D \\bar D$\nscattering in s-wave in order to shed light on this puzzle. The resulting phase\nshift supports the existence of a yet-unobserved narrow resonance with a mass\nslightly below 4 GeV. A scenario with this narrow resonance and a pole at\n$\\chi_{c0}(1P)$ agrees with the energy-dependence of our phase shift. Further\nlattice QCD simulations and experimental efforts are needed to resolve the\npuzzle of the excited scalar charmonia.",
        "positive": "Constraining a fourth generation of quarks: non-perturbative Higgs boson\n  mass bounds: We present a non-perturbative determination of the upper and lower Higgs\nboson mass bounds with a heavy fourth generation of quarks from numerical\nlattice computations in a chirally symmetric Higgs-Yukawa model. We find that\nthe upper bound only moderately rises with the quark mass while the lower bound\nincreases significantly, providing additional constraints on the existence of a\nstraight-forward fourth quark generation. We examine the stability of the lower\nbound under the addition of a higher dimensional operator to the scalar field\npotential using perturbation theory, demonstrating that it is not significantly\naltered for small values of the coupling of this operator. For a Higgs boson\nmass of $\\sim125\\mathrm{GeV}$ we find that the maximum value of the fourth\ngeneration quark mass is $\\sim300\\mathrm{GeV}$, which is already in conflict\nwith bounds from direct searches."
    },
    {
        "anchor": "A New Solution to Ginsparg-Wilson Relation from Generalized Staggered\n  Fermion: A generalized anti-hermitian staggered Dirac operator is formulated. Its\nrelation with noncommutative geometry is briefly reviewed. Once this\nanti-hermitian operator is modified to be ``$\\gamma^5$-hermitian'', it will\nprovide a new solution to Ginsparg-Wilson relation, basing on an abstract\nalgebraic analysis of Neuberger's overlap construction and a redefinition of\nchirality.",
        "positive": "Gapless Dirac Spectrum at High Temperature: Using the overlap Dirac operator I show that, contrary to some expectations,\neven well above the critical temperature there is not necessarily a gap in the\nDirac spectrum in pure SU(2) gauge theory. This happens when the Polyakov loop\nand the fermion boundary condition combine to give close to periodic boundary\ncondition for the fermions in the time direction. In this Polyakov loop sector\nthere is a non-vanishing density of Dirac eigenvalues around zero which implies\nthat chiral symmetry is spontaneously broken. I demonstrate this both directly\nand also by finding good agreement with the random matrix theory prediction for\nthe distribution of the lowest Dirac eigenvalue. I show that the chiral\ncondensate increases with the temperature therefore it is very unlikely to be\nexplained by topological fluctuations that become rapidly smaller above T_c.\nFinally I show that it is only a small fraction of the lowest Dirac eigenvalues\nthat decide which Polyakov loop sector is favored by the fermion determinant if\ndynamical fermions are turned on. This provides a qualitative understanding of\nhow the loss of confinement above T_c implies the restoration of chiral\nsymmetry."
    },
    {
        "anchor": "Acceleration of the Arnoldi method and real eigenvalues of the\n  non-Hermitian Wilson-Dirac operator: In this paper, we present a method for the computation of the low-lying real\neigenvalues of the Wilson-Dirac operator based on the Arnoldi algorithm. These\neigenvalues contain information about several observables. We used them to\ncalculate the sign of the fermion determinant in one-flavor QCD and the sign of\nthe Pfaffian in N=1 super Yang-Mills theory. The method is based on polynomial\ntransformations of the Wilson-Dirac operator, leading to considerable\nimprovements of the computation of eigenvalues. We introduce an iterative\nprocedure for the construction of the polynomials and demonstrate the\nimprovement in the efficiency of the computation. In general, the method can be\napplied to operators with a symmetric and bounded eigenspectrum.",
        "positive": "Static quark potential from centre vortices in the presence of dynamical\n  fermions: For the first time, centre vortices are identified on SU(3) lattice ensembles\nthat include dynamical fermions. Using a variational method, the static quark\npotential is calculated on untouched, vortex-removed, and vortex-only fields.\nTwo dynamical ensembles and one pure gauge ensemble are studied, allowing for\nan exploration of the impact of dynamical fermions on the centre-vortex vacuum.\nNovel modifications to the standard Coulomb term are introduced to describe the\nlong range behaviour of the vortex-removed potential. These modifications\nremove a source of systematic error in the fitted string tension on the\noriginal ensembles. Our pure Yang-Mills result is consistent with previous\nstudies, where projected centre-vortex fields only reproduce approximately two\nthirds of the string tension. Remarkably, we find that the vortex-only fields\non both dynamical lattices are able to fully reproduce the respective untouched\nstring tensions."
    },
    {
        "anchor": "Lattice QCD study of confinement and chiral symmetry breaking with\n  Dirac-mode expansion: Using the eigen-mode of the QCD Dirac operator $\\Slash D=\\gamma^\\mu D^\\mu$,\nwe develop a manifestly gauge-covariant expansion and projection of the QCD\noperators such as the Wilson loop and the Polyakov loop. With this method, we\nperform a direct analysis of the correlation between confinement and chiral\nsymmetry breaking in lattice QCD Monte Carlo calculations. Even after removing\nthe low-lying Dirac modes, which are responsible to chiral symmetry breaking,\nwe find that the Wilson loop obeys the area law, and the string tension or the\nconfinement force is almost unchanged. We find also that the Polyakov loop\nremains to be almost zero even without the low-lying Dirac modes, which\nindicates the Z_3-unbroken confinement phase. These results indicate that\none-to-one correspondence does not hold between confinement and chiral symmetry\nbreaking in QCD.",
        "positive": "Renormalized Polyakov loops in various representations in finite\n  temperature SU(2) gauge theory: We present results for the renormalized Polyakov loop in the three lowest\nirreducible representations of SU(2) gauge theory at finite temperature. We\nwill discuss their scaling behavior near $T_c$ and test Casimir scaling in the\ndeconfined phase. Moreover, we will compare these results to calculations for\nthe renormalized Polyakov loops in several representations in the SU(3) gauge\ntheory."
    },
    {
        "anchor": "Scaling, asymptotic scaling and Symanzik improvement. Deconfinement\n  temperature in SU(2) pure gauge theory: We report on a high statistics simulation of SU(2) pure gauge field theory at\nfinite temperature, using Symanzik action. We determine the critical coupling\nfor the deconfinement phase transition on lattices up to 8 x 24, using Finite\nSize Scaling techniques. We find that the pattern of asymptotic scaling\nviolation is essentially the same as the one observed with conventional, not\nimproved action. On the other hand, the use of effective couplings defined in\nterms of plaquette expectation values shows a precocious scaling, with respect\nto an analogous analysis of data obtained by the use of Wilson action, which we\ninterpret as an effect of improvement.",
        "positive": "Performance of Complex Langevin Simulation in 0+1 dimensional massive\n  Thirring model at finite density: Statistical sampling with the complex Langevin (CL) equation is applied to\n(0+1)-dimensional Thirring model, and its uniform-field variant, at finite\nfermion chemical potential $\\mu$. The CL simulation reproduces a crossover\nbehavior which is similar to but actually deviating from the exact solution in\nthe transition region, where we confirm that the CL simulation becomes\nsusceptible to the drift singularities, i.e., zeros of the fermion determinant.\nIn order to simulate the transition region with the CL method correctly, we\nexamine two approaches, a reweighting method and a model deformation, in both\nof which a single thimble with an attractive fixed point practically covers the\nintegration domain and the CL sampling avoids the determinant zeros. It turns\nout that these methods can reproduce the correct crossover behavior of the\noriginal model with using reference ensembles in the complexified space.\nHowever, they need evaluation of the reweighting factor, which scales with the\nsystem size exponentially. We discuss feasibility of applying these methods to\nthe Thirring model and to more realistic theories."
    },
    {
        "anchor": "EoS of finite density QCD with Wilson fermions by Multi-Parameter\n  Reweighting and Taylor expansion: The equation of state (EoS), quark number density and susceptibility at\nnonzero quark chemical potential $\\mu$ are studied in lattice QCD simulations\nwith a clover-improved Wilson fermion of 2-flavors and RG-improved gauge\naction. To access nonzero $\\mu$, we employ two methods : a multi-parameter\nreweighting (MPR) in $\\mu$ and $\\beta$ and Taylor expansion in $\\mu/T$. The use\nof a reduction formula for the Wilson fermion determinant enables to study the\nreweighting factor in MPR explicitly and heigher-order coefficients in Taylor\nexpansion free from errors of noise method, although calculations are limited\nto small lattice size. As a consequence, we can study the reliability of the\nthermodynamical quantities through the consistency of the two methods, each of\nwhich has different origin of the application limit.\n  The thermodynamical quantities are obtained from simulations on a $8^3\\times\n4$ lattice with an intermediate quark mass($m_{\\rm PS}/m_{\\rm V}=0.8)$. The MPR\nand Taylor expansion are consistent for the EoS and number density up to\n$\\mu/T\\sim 0.8$ and for the number susceptibility up to $\\mu/T \\sim 0.6$. This\nimplies within a given statistics that the overlap problem for the MPR and\ntruncation error for the Taylor expansion method are negligible in these\nregions.\n  In order to make MPR methods work, the fluctuation of the reweighting factor\nshould be small. We derive the equation of the reweighting line where the\nfluctuation is small, and show that the equation of the reweighting line is\nconsistent with the fluctuation minimum condition.",
        "positive": "Detailed Phase Transition Study at M_H <= 70 GeV in a 3-dimensional\n  $SU(2)$--Higgs Model: We study the electroweak phase transition in an effective 3-dimensional\ntheory for a Higgs mass of about 70 GeV by Monte Carlo simulations. The\ntransition temperature and jumps of order parameters are obtained and\nextrapolated to the continuum using multi-histogram techniques and finite size\nanalysis."
    },
    {
        "anchor": "Improving the Partial-Global Stochastic Metropolis Update for Dynamical\n  Smeared Link Fermions: We discuss several methods that improve the partial-global stochastic\nMetropolis (PGSM) algorithm for smeared link staggered fermions. We present\nautocorrelation time measurements and argue that this update is feasible even\non reasonably large lattices.",
        "positive": "The Analysis of Space-Time Structure in QCD Vacuum II: Dynamics of\n  Polarization and Absolute X-Distribution: We propose a framework for quantitative evaluation of dynamical tendency for\npolarization in arbitrary random variable that can be decomposed into a pair of\northogonal subspaces. The method uses measures based on comparisons of given\ndynamics to its counterpart with statistically independent components. The\nformalism of previously considered X-distributions is used to express the\naforementioned comparisons, in effect putting the former approach on solid\nfooting. Our analysis leads to definition of a suitable correlation coefficient\nwith clear statistical meaning. We apply the method to the dynamics induced by\npure-glue lattice QCD in local left-right components of overlap Dirac\neigenmodes. It is found that, in finite physical volume, there exists a\nnon-zero physical scale in the spectrum of eigenvalues such that eigenmodes at\nsmaller (fixed) eigenvalues exhibit convex X-distribution (positive\ncorrelation), while at larger eigenvalues the distribution is concave (negative\ncorrelation). This chiral polarization scale thus separates a regime where\ndynamics enhances chirality relative to statistical independence from a regime\nwhere it suppresses it, and gives an objective definition to the notion of\n\"low\" and \"high\" Dirac eigenmode. We propose to investigate whether the\npolarization scale remains non-zero in the infinite volume limit, in which case\nit would represent a new kind of low energy scale in QCD."
    },
    {
        "anchor": "Spin-Orbit Force from Lattice QCD: We present a first attempt to determine nucleon-nucleon potentials in the\nparity-odd sector, which appear in 1P1, 3P0, 3P1, 3P2-3F2 channels, in Nf=2\nlattice QCD simulations. These potentials are constructed from the\nNambu-Bethe-Salpeter wave functions for J^P=0^-, 1^- and 2^-, which correspond\nto A1^-, T1^- and T2^- + E^- representation of the cubic group, respectively.\nWe have found a large and attractive spin-orbit potential VLS(r) in the\nisospin-triplet channel, which is qualitatively consistent with the\nphenomenological determination from the experimental scattering phase shifts.\nThe potentials obtained from lattice QCD are used to calculate the scattering\nphase shifts in 1P1, 3P0, 3P1 and 3P2-3F2 channels. The strong attractive\nspin-orbit force and a weak repulsive central force in spin-triplet P-wave\nchannels lead to an attraction in the 3P2 channel, which is related to the\nP-wave neutron paring in neutron stars.",
        "positive": "Monopole Currents in U(1) Lattice Gauge Theory: A Comparison to an\n  Effective Model based on Dual Superconductivity: We compare U(1) lattice gauge theory to an effective model of Maxwell and\nLondon equations. In the effective model there is only one free parameter, the\nLondon penetration depth lambda. It turns out that one can get good agreement\nbetween both models if one modifies the usual definition of magnetic monopole\ncurrents in U(1) lattice gauge theory. This comparison also shows that already\nat small distances fluctuations of the occuring string are important. Further,\nwe investigate the beta-dependence of the penetration depth and determine the\nsuppression of the monopole condensate in flux tubes."
    },
    {
        "anchor": "On the phase structure of QCD with Wilson fermions: The phase structure of lattice QCD with Wilson fermions is discussed.\nAnalytic and numerical evidences are given for the spontaneous breaking of\nparity and flavor symmetry, which naturally explains the existence of the\nmassless pion at the critical hopping parameter $K_c$ without recourse to the\nchiral symmetry absent in the Wilson fermion formulation. New numerical\nevidences are also presented for the multiple structure of the critical lines\nin the weak coupling region. A connection between the phase structure and the\nfinite temperature phase transition is briefly mentioned.",
        "positive": "Roper Resonance in 2+1 Flavor QCD: The low-lying even-parity states of the nucleon are explored in lattice QCD\nusing the PACS-CS collaboration 2+1-flavor dynamical-QCD gauge-field\nconfigurations made available through the International Lattice Datagrid\n(ILDG). The established correlation-matrix approach is used, in which various\nfermion source and sink smearings are utilized to provide an effective basis of\ninterpolating fields to span the space of low-lying energy eigenstates. Of\nparticular interest is the nature of the first excited state of the nucleon,\nthe $N{1/2}^{+}$ Roper resonance of $P_{11}$ pion-nucleon scattering. The Roper\nstate of the present analysis approaches the physical mass, displaying\nsignificant chiral curvature at the lightest quark mass. These full QCD\nresults, providing the world's first insight into the nucleon mass spectrum in\nthe light-quark regime, are significantly different from those of quenched QCD\nand provide interesting insights into the dynamics of QCD."
    },
    {
        "anchor": "Towards thermodynamics with $N_f=2+1+1$ twisted mass quarks: We present preliminary results achieved within a recently started project\ndealing with QCD thermodynamics in the presence of a fully dynamical second\nquark family. We are employing the Wilson twisted mass discretization. To\nreduce the amount of zero temperature simulations and the cost of analysis we\nhave chosen the fixed-scale approach. We show a variety of basic thermodynamic\nobservables for temperatures ranging from 158 to 633 MeV. Simulations were\nperformed for three lattice spacings below 0.1 fm each and at a single value of\nthe pion mass which allows a comparison with previously obtained $N_f=2$\nresults. We determine the chiral crossover temperature from the bare chiral\nsusceptibility and show results for the gauge part of the trace anomaly.",
        "positive": "Long distance contribution to the $K_L-K_S$ mass difference: We develop and demonstrate techniques needed to compute the long distance\ncontribution to the $K_{L}$-$K_{S}$ mass difference, $\\Delta M_K$, in lattice\nQCD and carry out a first, exploratory calculation of this fundamental\nquantity. The calculation is performed on 2+1 flavor, domain wall fermion,\n$16^3\\times32$ configurations with a 421 MeV pion mass and an inverse lattice\nspacing $1/a=1.73$ GeV. We include only current-current operators and drop all\ndisconnected and double penguin diagrams. The short distance part of the mass\ndifference in a 2+1 flavor calculation contains a quadratic divergence cut off\nby the lattice spacing. Here, this quadratic divergence is eliminated through\nthe GIM mechanism by introducing a valence charm quark. The inclusion of the\ncharm quark makes the complete calculation accessible to lattice methods\nprovided the discretization errors associated with the charm quark can be\ncontrolled. The long distance effects are discussed for each parity channel\nseparately. While we can see a clear signal in the parity odd channel, the\nsignal to noise ratio in the parity even channel is exponentially decreasing as\nthe separation between the two weak operators increases. We obtain a mass\ndifference $\\Delta M_K$ which ranges from $6.58(30)\\times 10^{-12}$ MeV to\n$11.89(81)\\times 10^{-12}$ MeV for kaon masses varying from 563 MeV to 839 MeV.\nExtensions of these methods are proposed which promise accurate results for\nboth $\\Delta M_K$ and $\\epsilon_K$, including long distance effects."
    },
    {
        "anchor": "Probing the proton and its excitations in full QCD: We present a first look at the application of variational techniques for the\nextraction of the electromagnetic properties of an excited nucleon system. In\nparticular, we include preliminary results for charge radii and magnetic\nmoments of the proton, its first even-parity excitation and the $\\Delta^{+}$.",
        "positive": "Phase Structure of Lattice N=4 Super Yang-Mills: We make a first study of the phase diagram of four-dimensional N=4 super\nYang-Mills theory regulated on a space-time lattice. The lattice formulation we\nemploy is both gauge invariant and retains at all lattice spacings one exactly\npreserved supersymmetry charge. Our numerical results are consistent with the\nexistence of a single deconfined phase at all observed values of the bare\ncoupling."
    },
    {
        "anchor": "Fun with Dirac eigenvalues: It is popular to discuss low energy physics in lattice gauge theory in terms\nof the small eigenvalues of the lattice Dirac operator. I play with some\nensuing pitfalls in the interpretation of these eigenvalue spectra.",
        "positive": "Dual Lattice Blockspin Transformation and Monopole condensation in QCD: Recent studies of confinement based on the idea of abelian monopole\ncondensation are reviewed briefly. Emphasis is placed on the approach to get\nthe effective monoole action using the blockspin transformation on the dual\nlattice. The trajectory obtained looks to be the renormalized one in $SU(2)$\nQCD. A disorder parameter of confinement is constructed. Monopole condensation\noccurs also in $SU(3)$ QCD."
    },
    {
        "anchor": "Nucleon matrix elements with domain wall fermions: We present the status of our calculation of the first few moments of the\nnucleon structure functions. Our calculations are done using domain wall\nfermions in the quenched approximation with the DBW2 gauge action at 1.3GeV\ninverse lattice spacing.",
        "positive": "Recent Progress in Lattice QCD: Recent progress in Lattice QCD is highlighted. After a brief introduction to\nthe methodology of lattice computations the presentation focuses on three main\ntopics: Hadron Spectroscopy, Hadron Structure and Lattice Flavor Physics. In\neach case a summary of recent computations of selected quantities is provided."
    },
    {
        "anchor": "Quenched divergences in the deconfined phase of SU(2) gauge theory: The spectrum of the overlap Dirac operator in the deconfined phase of\nquenched gauge theory is known to have three parts: exact zeros arising from\ntopology, small nonzero eigenvalues that result in a non-zero chiral\ncondensate, and the dense bulk of the spectrum, which is separated from the\nsmall eigenvalues by a gap. In this paper, we focus on the small nonzero\neigenvalues in an SU(2) gauge field background at $\\beta=2.4$ and $N_T=4$. This\nlow-lying spectrum is computed on four different spatial lattices ($12^3$,\n$14^3$, $16^3$, and $18^3$). As the volume increases, the small eigenvalues\nbecome increasingly concentrated near zero in such a way as to strongly suggest\nthat the infinite volume condensate diverges.",
        "positive": "Applying Groebner Bases to Solve Reduction Problems for Feynman\n  Integrals: We describe how Groebner bases can be used to solve the reduction problem for\nFeynman integrals, i.e. to construct an algorithm that provides the possibility\nto express a Feynman integral of a given family as a linear combination of some\nmaster integrals. Our approach is based on a generalized Buchberger algorithm\nfor constructing Groebner-type bases associated with polynomials of shift\noperators. We illustrate it through various examples of reduction problems for\nfamilies of one- and two-loop Feynman integrals. We also solve the reduction\nproblem for a family of integrals contributing to the three-loop static quark\npotential."
    },
    {
        "anchor": "Non-perturbative Heavy Quark Effective Theory: An application to\n  semi-leptonic B-decays: We review a lattice strategy how to non-perturbatively determine the\ncoefficients in the HQET expansion of all components of the heavy-light axial\nand vector currents, including 1/m_h-corrections. We also discuss recent\npreliminary results on the form factors parameterizing semi-leptonic B-decays\nat the leading order in 1/m_h.",
        "positive": "$Sp(2N)$ Yang-Mills theories on the lattice: scale setting and topology: We study Yang-Mills lattice theories with $Sp(N_c)$ gauge group, with\n$N_c=2N$, for $N=1,\\,\\cdots,\\,4$. We show that if we divide the renormalised\ncouplings appearing in the Wilson flow by the quadratic Casimir $C_2(F)$ of the\n$Sp(N_c)$ group, then the resulting quantities display a good agreement among\nall values of $N_c$ considered, over a finite interval in flow time. We use\nthis scaled version of the Wilson flow as a scale-setting procedure, compute\nthe topological susceptibility of the $Sp(N_c)$ theories, and extrapolate the\nresults to the continuum limit for each $N_c$."
    },
    {
        "anchor": "Nf=2 Lattice QCD and Chiral Perturbation Theory: By employing a twisted mass term, we compare recent results from lattice\ncalculations of Nf=2 dynamical Wilson fermions with Wilson Chiral Perturbation\nTheory (WChPT). The final goal is to determine some combinations of\nGasser-Leutwyler Low Energy Constants (LECs). A wide set of data with different\nlattice spacings (a ~ 0.2-0.12 fm), different gauge actions (Wilson plaquette,\nDBW2) and different quark masses (down to the lowest pion mass allowed by\nlattice artifacts and including negative quark masses) provide a strong check\nof the applicability of WChPT in this regime and the scaling behaviours in the\ncontinuum limit.",
        "positive": "Chirally improving Wilson fermions III. The Schr\u00f6dinger functional: We show that it is possible to construct a lattice Schroedinger functional\nfor standard Wilson fermions, where the expectation values of ${\\cal R}_5$-even\noperators are O($a$) improved, up to terms coming from the boundaries."
    },
    {
        "anchor": "The Massive Schwinger Model in a Fast Moving Frame: We present a non-perturbative study of the massive Schwinger model. We use a\nHamiltonian approach, based on a momentum lattice corresponding to a fast\nmoving reference frame, and equal time quantization.",
        "positive": "The Interface Tension in Quenched QCD at the Critical Temperature: We present results for the confinement-deconfinement interface tension\n$\\alpha_{cd}$ of quenched QCD. They were obtained by applying Binder's\nhistogram method to lattices of size $L^2\\times L_z\\times L_t$ for $L_t=2$ and\n$L=8,10,12\\mbox{ and }14$ with $L_z=30$ for $L=8$ and $L_z=3L$ otherwise. The\nuse of a multicanonical algorithm and cylindrical geometries have turned out to\nbe crucial for the numerical studies."
    },
    {
        "anchor": "Insight into the Scalar Mesons from a Lattice Calculation: We study the possibility that the light scalar mesons are (qbar qbar q q)\nstates rather than (qbar q). We perform a lattice QCD calculation of\npseudoscalar meson scattering amplitudes, ignoring quark loops and quark\nannihilation, and find indications that for sufficiently heavy quarks there is\na stable four-quark bound state with J^{PC}=0^{++} and non-exotic flavor\nquantum numbers.",
        "positive": "Towards learning optimized kernels for complex Langevin: We present a novel strategy aimed at restoring correct convergence in complex\nLangevin simulations. The central idea is to incorporate system-specific prior\nknowledge into the simulations, in order to circumvent the NP-hard sign\nproblem. In order to do so, we modify complex Langevin using kernels and\npropose the use of modern auto-differentiation methods to learn optimal kernel\nvalues. The optimization process is guided by functionals encoding relevant\nprior information, such as symmetries or Euclidean correlator data. Our\napproach recovers correct convergence in the non-interacting theory on the\nSchwinger-Keldysh contour for any real-time extent. For the strongly coupled\nquantum anharmonic oscillator we achieve correct convergence up to three-times\nthe real-time extent of the previous benchmark study. An appendix sheds light\non the fact that for correct convergence not only the absence of boundary\nterms, but in addition the correct Fokker-Plank spectrum is crucial."
    },
    {
        "anchor": "Fixed Point Gauge Actions with Fat Links: Scaling and Glueballs: A new parametrization is introduced for the fixed point (FP) action in SU(3)\ngauge theory using fat links. We investigate its scaling properties by means of\nthe static quark-antiquark potential and the dimensionless quantities $r_0 T_c,\nT_c/\\sqrt{\\sigma}$ and $r_0 \\sqrt{\\sigma}$, where $T_c$ is the critical\ntemperature of the deconfining phase transition, $r_0$ is the hadronic scale\nand $\\sigma$ is the effective string tension. These quantities scale even on\nlattices as coarse as $a \\approx 0.3$ fm. We also measure the glueball spectrum\nand obtain $m_{0^{++}}=1627(83)$ MeV and $m_{2^{++}}=2354(95)$ MeV for the\nmasses of the scalar and tensor glueballs, respectively.",
        "positive": "Mass of the B_c Meson in Three-Flavor Lattice QCD: We use lattice QCD to predict the mass of the $B_c$ meson. We use the MILC\nCollaboration's ensembles of lattice gauge fields, which have a quark sea with\ntwo flavors much lighter than a third. Our final result is\n$m_{B_c}=6304\\pm12^{+18}_{- 0} MeV$. The first error bar is a sum in quadrature\nof statistical and systematic uncertainties, and the second is an estimate of\nheavy-quark discretization effects."
    },
    {
        "anchor": "Nucleon strange electromagnetic form factors: The role of the strange quarks on the low-energy interactions of the proton\ncan be probed through the strange electromagnetic form factors. Knowledge of\nthese form factors provides essential input for parity-violating processes and\ncontributes to the understanding of the sea quark dynamics. We determine the\nstrange electromagnetic form factors of the nucleon within the lattice\nformulation of Quantum Chromodynamics using simulations that include light,\nstrange and charm quarks in the sea all tuned to their physical mass values. We\nemploy state-of-the-art techniques to accurately extract the form factors for\nvalues of the momentum transfer square up to 0.8~GeV$^2$. We find that both the\nelectric and magnetic form factors are statistically non-zero. We obtain for\nthe strange magnetic moment $\\mu^s=-0.017(4)$, the strange magnetic radius\n$\\langle r^2_M \\rangle^s=-0.015(9)$~fm$^2$, and the strange charge radius\n$\\langle r^2_E \\rangle^s=-0.0048(6)$~fm$^2$.",
        "positive": "Continuum limit and universality of the Columbia plot: Results on the thermal transition of QCD with 3 degenerate flavors, in the\nlower-left corner of the Columbia plot, are puzzling. The transition is\nexpected to be first-order for massless quarks, and to remain so for a range of\nquark masses until it turns second-order at a critical quark mass. But this\ncritical quark mass and resulting \"pion\" mass disagree violently between Wilson\nand staggered fermions at finite lattice spacing, and decrease sharply with the\nlattice spacing, for staggered fermions at least. To clarify this puzzle and\neliminate potential systematic effects from rooting, we study the 4-flavor\ntheory with staggered fermions, on lattices with 4 to 10 time-slices. Our\nresults are qualitatively similar to the 3-flavor case, so that rooting is not\nan issue. However, dramatic cutoff effects are visible, even on our finest\nlattices. Universality implies that cutoff effects for Wilson fermions are even\nmore dramatic. In order to obtain a first-order thermal transition in the\ncontinuum theory, extremely light quarks are needed."
    },
    {
        "anchor": "The Light-Quark Magnetic Moment of the Lambda(1405) Antikaon-Nucleon\n  Molecule: The light-quark sector of the Lambda(1405) baryon is examined in the context\nof the recent discovery of a dominant antikaon-nucleon composition at low quark\nmasses. Further evidence for this interpretation of the Lambda(1405) is\npresented, by calculating the u and d quark contributions to the Lambda(1405)\nmagnetic form factors in lattice QCD. The extent to which these quantities are\nconsistent with the exotic molecular description can then be quantified by\ncomparing the results with the equivalent nucleon form factors. Drawing on a\nrecent extension of the graded-symmetry approach for the flavor-singlet\ncomponents of the Lambda(1405), the separation of the connected and\ndisconnected contributions is performed in both the flavor-octet and singlet\nrepresentations. In both cases, the disconnected loop contributions are found\nto be unexpectedly large. The relationship between the light-quark\ncontributions to the Lambda(1405) magnetic form factor and the connected\ncontributions of the nucleon magnetic form factors is thus confirmed in the\ncase of lattice QCD, establishing compelling evidence for a KN molecular\nstructure of the Lambda(1405) near the physical point.",
        "positive": "Hadron spectra and Delta_{mix} from overlap quarks on a HISQ sea: We present results of our continuing study on mixed-action hadron spectra and\ndecay constants using overlap valence quarks on MILC's 2+1+1 flavor HISQ gauge\nconfigurations. This study is carried out on three lattice spacings, with charm\nand strange masses tuned to their physical values, and with m_l/m_s = 1/5. We\npresent results of an ongoing determination of the mixed-action parameter\nDelta_{mix}, which enters into chiral formulae for the masses and decay\nconstants."
    },
    {
        "anchor": "Monopole and instanton effects in QCD: We aim to show the effects of the magnetic monopoles and instantons in\nquantum chromodynamics (QCD) on observables; therefore, we introduce a monopole\nand anti-monopole pair in the QCD vacuum of a quenched SU(3) by applying the\nmonopole creation operator to the vacuum. We calculate the eigenvalues and\neigenvectors of the overlap Dirac operator that preserves the exact chiral\nsymmetry in lattice gauge theory using these QCD vacua. We then investigate the\neffects of magnetic monopoles and instantons. First, we confirm the monopole\neffects as follows: (i) The monopole creation operator makes the monopoles and\nanti-monopoles in the QCD vacuum. (ii) A monopole and anti-monopole pair\ncreates an instanton or anti-instanton without changing the structure of the\nQCD vacuum. (iii) The monopole and anti-monopole pairs change only the scale of\nthe spectrum distribution without affecting the spectra of the Dirac operator\nby comparing the spectra with random matrix theory. Next, we find the instanton\neffects by increasing the number density of the instantons and anti-instantons\nas follows: (iv) The decay constants of the pseudoscalar increase. (v) The\nvalues of the chiral condensate, which are defined as negative numbers,\ndecrease. (vi) The light quarks and the pseudoscalar mesons become heavy. The\ncatalytic effect on the charged pion is estimated using the numerical results\nof the pion decay constant and the pion mass. (vii) The decay width of the\ncharged pion becomes wider than the experimental result, and the lifetime of\nthe charged pion becomes shorter than the experimental result. These are the\neffects of the monopoles and instantons in QCD.",
        "positive": "Ising Spins on Thin Graphs: The Ising model on ``thin'' graphs (standard Feynman diagrams) displays\nseveral interesting properties. For ferromagnetic couplings there is a mean\nfield phase transition at the corresponding Bethe lattice transition point. For\nantiferromagnetic couplings the replica trick gives some evidence for a spin\nglass phase. In this paper we investigate both the ferromagnetic and\nantiferromagnetic models with the aid of simulations. We confirm the Bethe\nlattice values of the critical points for the ferromagnetic model on $\\phi^3$\nand $\\phi^4$ graphs and examine the putative spin glass phase in the\nantiferromagnetic model by looking at the overlap between replicas in a\nquenched ensemble of graphs. We also compare the Ising results with those for\nhigher state Potts models and Ising models on ``fat'' graphs, such as those\nused in 2D gravity simulations."
    },
    {
        "anchor": "The standard model and parity conservation: On the basis of previous work on chiral gauged fermions on a lattice, we\ndiscuss the lattice-regularization of the standard model by introducing two\nWeyl fields interacting with quarks and leptons. These interactions form\nmassive bound states to gauge-invariantly decouple doublers at high energies\nand these bound states dissolve into their constituents at low energies. No any\nhard spontaneous symmetry breakings occur at the lattice scale \\pi/a. As a\nconsequence, the gauge symmetries of the standard model are realized by both\nmassive vectorlike spectra at high energies and massless chiral spectra at low\nenergies. Such a scenario is consistent with the gauge-anomaly cancelation,\nflavor-singlet anomaly and Witten's anomaly. These studies predict that the\nparity symmetry must be restored at high energies.",
        "positive": "Perturbative renormalization factors of four-quark operators for\n  improved Wilson fermion action and Iwasaki gauge action: The renormalization factor and O(a) improvement coefficient of four-quark\noperators are calculated perturbatively for the improved Wilson fermion action\nwith clover term and the Iwasaki gauge action. With an application to the\n$K\\to\\pi\\pi$ decay amplitude in mind, the calculation is restricted to the\nparity odd operator, for which the operators are multiplicatively renormalized\nwithout any mixing to operators that have different chiral structures."
    },
    {
        "anchor": "Fluctuations Destroying Long-Range Order in SU(2) Yang-Mills Theory: We study lattice SU(2) Yang-Mills theory with dimension $d\\ge 4$. The model\ncan be expressed as a $(d-1)$-dimensional O(4) non-linear $\\sigma$-model in a\n$d$-dimensional heat bath. As is well known, the non-linear $\\sigma$-model\nalone shows a phase transition. If the quark confinement is a consequence of\nabsence of a phase transition for the Yang-Mills theory, then the fluctuations\nof the heat bath must destroy the long-range order of the non-linear\n$\\sigma$-model. In order to clarify whether this is true, we replace the\nfluctuations of the heat bath with Gaussian random variables, and obtain a\nLangevin equation which yields the effective action of the non-linear\n$\\sigma$-model through analyzing the Fokker-Planck equation. It turns out that\nthe fluctuations indeed destroy the long-range order of the non-linear\n$\\sigma$-model within a mean field approximation estimating a critical point,\nwhereas for the corresponding U(1) gauge theory, the phase transition to the\nmassless phase remains against the fluctuations.",
        "positive": "Thermal QCD phase transition with dynamical chiral fermions: We discuss properties of Quantum Chromodynamics at finite temperature\nobtained by means of lattice simulations with overlap fermions. This fermion\ndiscretization preserves chiral symmetry even at finite lattice spacing. We\npresent details of the lattice formulation, first results for the chiral\nobservables and discuss the behaviour of the system near the chiral thermal\nphase transition."
    },
    {
        "anchor": "Toward Exploring Phase Diagrams of Gauge Theories on Quantum Computers\n  with Thermal Pure Quantum States: Aiming at evading the notorious sign problem in classical Monte-Carlo\napproaches to lattice quantum chromodynamics, we present an approach for\nquantum computing finite-temperature lattice gauge theories at non-zero\ndensity. Based on the thermal pure-quantum-state formalism of statistical\nmechanics when extended to gauge-theory systems, our approach allows for\nsign-problem-free quantum computations of thermal expectation values and\nnon-equal time correlation functions. By taking a simple lattice gauge theory\nfor which classical benchmarks are possible, namely $\\mathbb{Z}_2$ lattice\ngauge theory in 1+1 dimensions at finite chemical potential, we discuss\nresource requirements and robustness to algorithmic and hardware imperfections\nfor near-term quantum-hardware realizations.",
        "positive": "Probing QCD perturbation theory at high energies with continuum\n  extrapolated lattice data: Precision tests of QCD perturbation theory are not readily available from\nexperimental data. The main reasons are systematic uncertainties due to the\nconfinement of quarks and gluons, as well as kinematical constraints which\nlimit the accessible energy scales. We here show how continuum extrapolated\nlattice data may overcome such problems and provide excellent probes of\nrenormalized perturbation theory. This work corresponds to an essential step in\nthe ALPHA collaboration's project to determine the $\\Lambda$-parameter in\n3-flavour QCD. I explain the basic techniques used in the high energy regime,\nnamely the use of mass-independent renormalization schemes for the QCD coupling\nconstant in a finite Euclidean space time volume. When combined with finite\nsize techniques this allows one to iteratively step up the energy scale by\nfactors of 2, thereby quickly covering two orders of magnitude in scale. We may\nthen compare perturbation theory (with $\\beta$-functions available up to 3-loop\norder) to our non-perturbative data for a 1-parameter family of running\ncouplings. We conclude that a target precision of 3 percent for the\n$\\Lambda$-parameter requires non-perturbative data up to scales where\n$\\alpha_s\\approx 0.1$, whereas the apparent precision obtained from applying\nperturbation theory around $\\alpha_s \\approx 0.2$ can be misleading. This\nshould be taken as a general warning to practitioners of QCD perturbation\ntheory."
    },
    {
        "anchor": "Fractional Charge and Confinement of Quarks: In quantum chromodynamics with static quarks the confinement-deconfinement\nphase transition is connected to the spontaneous breaking of the global Z3\ncenter symmetry. This symmetry is lost when one considers dynamical quarks.\nOwing to the fractional electric charge of quarks, we recover a global Z6\ncenter symmetry when QCD is regarded as a part of the Standard Model. We\npresent results from QCD-like theories extended by electromagnetic interactions\nand show that the weak coupling limit of the QED part of the model results in a\ncenter-like symmetry with disorder in the vacuum. This can be seen explicitly\nin a character expansion of the fermion determinant. Further, we show that\ncorresponding center averages project the fermion determinant on N-ality zero\nand discuss whether the additional center symmetry can be used to eliminate the\nfermion sign problem in QCD with fundamental quarks.",
        "positive": "Relativistic, model-independent determination of electromagnetic\n  finite-size effects beyond the point-like approximation: We present a relativistic and model-independent method to derive\nstructure-dependent electromagnetic finite-size effects. This is a systematic\nprocedure, particularly well-suited for automatization, which works at\narbitrarily high orders in the large-volume expansion. Structure-dependent\ncoefficients appear as zero-momentum derivatives of physical form factors which\ncan be obtained through experimental measurements or auxiliary lattice\ncalculations. As an application we derive the electromagnetic finite-size\neffects on the pseudoscalar meson mass and leptonic decay amplitude, through\norders $\\mathcal{O}(1/L^3)$ and $\\mathcal{O}(1/L^2)$, respectively. The\nstructure dependence appears at this order through the meson charge radius and\nthe real radiative leptonic amplitude, which are known experimentally."
    },
    {
        "anchor": "Truncated Determinant Approach to Light Dynamical Quarks: Virtual quark effects in lattice QCD are studied in an approach where the\ninfrared modes are included in a precise and gauge-invariant manner. At fixed\nphysical volume the required number of modes does not increase in the continuum\nlimit, and the acceptance is tolerable even for very light quark masses.\nTopological charge distributions at varying quark mass, and the static quark\npotential, showing the onset of string-breaking, are presented in both QED2 and\nQCD4.",
        "positive": "Baryon correlators containing different diquarks from lattice\n  simulations: Point to point vacuum correlators containing diquarks in the color\nanti-triplet representation are computed both in the quenched approximation and\ndynamical overlap simulations with two flavors. The scalar, pseudoscalar and\naxial vector diquarks are combined with light quarks to form color singlets.\nThe scalar (\"good\") diquark channel shows a stronger attraction than the axial\nvector (\"bad\") channel in the quenched data set. The pseudoscalar diquark\nchannel shows a finite volume zero mode artifact: the correlator becomes\nnegative at large distance when the quark mass is small. By separating\nconfigurations without zero modes from those with zero modes, we found that the\nzero modes have an important contribution in both the attraction in the scalar\nchannel and the repulsion in the pseudoscalar channel. In the axial vector\ndiquark channel, we did not find apparent zero mode effects."
    },
    {
        "anchor": "Scaling and Asymptotic Scaling in the SU(2) Gauge Theory: We determine the critical couplings for the deconfinement phase transition in\n$SU(2)$ gauge theory on $N_\\tau \\times N_\\sigma^3$ lattices with $N_\\tau = 8$\nand 16 and $N_\\sigma$ varying between 16 and 48. A comparison with string\ntension data shows scaling of the ratio $T_c / \\sqrt{\\sigma}$ in the entire\ncoupling regime $\\beta =2.30-2.75$, while the individual quantities still\nexhibit large scaling violations. We find $T_c / \\sqrt{\\sigma}=0.69(2)$. We\nalso discuss in detail the extrapolation of $T_c / Lambda_{\\rm{\\bar{M}\n\\bar{S}}}$ and $\\sqrt{\\sigma} / Lambda_{\\rm{\\bar{M}\\bar{S}}}$ to the continuum\nlimit. Our result, which is consistent with the above ratio, is $T_c /\nLambda_{\\rm{\\bar{M}\\bar{S}}} = 1.23(11)$ and $\\sqrt{\\sigma} /\nLambda_{\\rm{\\bar{M}\\bar{S}}} = 1.79(12)$. We also comment upon corresponding\nresults for $SU(3)$ gauge theory and four flavour QCD.",
        "positive": "Relation between scattering amplitude and Bethe-Salpeter wave function\n  in quantum field theory: We reexamine the relations between the Bethe-Salpeter (BS) wave function of\ntwo particles, the on-shell scattering amplitude, and the effective potential\nin quantum filed theory. It is emphasized that there is an exact relation\nbetween the BS wave function inside the interaction range and the scattering\namplitude, and the reduced BS wave function, which is defined in this article,\nplays an essential role in this relation. Based on the exact relation, we show\nthat the solution of Schr\\\"odinger equation with the effective potential gives\nus a correct on-shell scattering amplitude only at the momentum where the\neffective potential is calculated, while wrong results are obtained from the\nSchr\\\"odinger equation at general momenta. We also discuss about a momentum\nexpansion of the reduced BS wave function and an uncertainty of the scattering\namplitude stemming from the choice of the interpolating operator in the BS wave\nfunction. The theoretical conclusion obtained in this article could give hints\nto understand the inconsistency observed in lattice QCD calculation of the\ntwo-nucleon channels with different approaches."
    },
    {
        "anchor": "N=4 Supersymmetry on a Space-Time Lattice: Maximally supersymmetric Yang--Mills theory in four dimensions can be\nformulated on a space-time lattice while exactly preserving a single\nsupersymmetry. Here we explore in detail this lattice theory, paying particular\nattention to its strongly coupled regime. Targeting a theory with gauge group\nSU(N), the lattice formulation is naturally described in terms of gauge group\nU(N). Although the U(1) degrees of freedom decouple in the continuum limit we\nshow that these degrees of freedom lead to unwanted lattice artifacts at strong\ncoupling. We demonstrate that these lattice artifacts can be removed, leaving\nbehind a lattice formulation based on the SU(N) gauge group with the expected\napparently conformal behavior at both weak and strong coupling.",
        "positive": "On-shell and off-shell improvement for Ginsparg-Wilson fermions: We discuss the improvement of bilinear fermionic operators for\nGinsparg-Wilson fermions. We present explicit formulae for improved Green's\nfunctions, which apply both on-shell and off-shell."
    },
    {
        "anchor": "Two dimensional CP^2 Model with \u03b8-term and Topological Charge\n  Distributions: Topological charge distributions in 2 dimensional CP^2 model with theta-term\nis calculated. In strong coupling regions, topological charge distribution is\napproximately given by Gaussian form as a function of topological charge and\nthis behavior leads to the first order phase transition at \\theta=\\pi. In weak\ncoupling regions it shows non-Gaussian distribution and the first order phase\ntransition disappears. Free energy as a function of \\theta shows \"flattening\"\nbehavior at theta=theta_f<pi, when we calculate the free energy directly from\ntopological charge distribution. Possible origin of this flattening phenomena\nis prensented.",
        "positive": "Exotics in the $\u03c0D$ system: In this proceedings we consider several states, namely the $D^*_{s0}(2317)$,\n$D_{s1}(2460)$, $D^*_{0}(2300)$ and $D_{1}(2430)$, which appear to defy\ndescription as simple quark-antiquark pairs. Theoretical input from unitarized\nchiral perturbation theory suggests they can be understood as emerging from\nGoldstone-Boson--$D$-meson scattering.\n  We present results from an $SU(3)$ flavor-symmetric lattice QCD simulation at\nlarge pion masses suggesting that there exists a $\\pi D$ bound state in the\nflavor-sextet representation that cannot emerge for quark-antiquark states, but\nthat appears naturally from the multiquark states. Moreover, we find repulsion\nin the [15] representation, which establishes the pattern predicted for the\ninteractions of Goldstone bosons with $D$ mesons. This suggests these states\nmay have the structure of hadronic molecules."
    },
    {
        "anchor": "Effective sigma models and lattice Ward identities: We perform a lattice analysis of the Faddeev-Niemi effective action\nconjectured to describe the low-energy sector of SU(2) Yang-Mills theory. To\nthis end we generate an ensemble of unit vector fields (\"color spins\") n from\nthe Wilson action. The ensemble does not show long-range order but exhibits a\nmass gap of the order of 1 GeV. From the distribution of color spins we\nreconstruct approximate effective actions by means of exact lattice\nSchwinger-Dyson and Ward identities (\"inverse Monte Carlo\"). We show that the\ngenerated ensemble cannot be recovered from a Faddeev-Niemi action, modified in\na minimal way by adding an explicit symmetry-breaking term to avoid the\nappearance of Goldstone modes.",
        "positive": "Operators for scattering of particles with spin: Operators for simulating the scattering of two particles with spin are\nconstructed. Three methods are shown to give the consistent lattice operators\nfor PN, PV, VN and NN scattering, where P, V and N denote pseudoscalar meson,\nvector meson and nucleon. The projection method leads to one or several\noperators $O_{\\Gamma,r,n}$ that transform according to a given irreducible\nrepresentation $\\Gamma$ and row r. However, it gives little guidance on which\ncontinuum quantum numbers of total J, spin S, orbital momentum L or\nsingle-particle helicities $\\lambda_{1,2}$ will be related with a given\noperator. This is remedied with the helicity and partial-wave methods. There\nfirst the operators with good continuum quantum numbers $(J,P,\\lambda_{1,2})$\nor $(J,L,S)$ are constructed and then subduced to the irreps $\\Gamma$ of the\ndiscrete lattice group. The results indicate which linear combinations\n$O_{\\Gamma,r,n}$ of various n have to be employed in the simulations in order\nto enhance couplings to the states with desired continuum quantum numbers. The\ntotal momentum of two hadrons is restricted to zero since parity P is a good\nquantum number in this case."
    },
    {
        "anchor": "The Microscopic Twisted Mass Dirac Spectrum: The microscopic spectral density for lattice QCD with two flavors and\nmaximally twisted mass is computed. The results are given for fixed index of\nthe Dirac operator and include the leading order $a^2$ corrections to the\nchiral Lagrangian due to the discretization errors. The computation is carried\nout within the framework of Wilson chiral perturbation theory.",
        "positive": "Axial couplings of heavy hadrons from domain-wall lattice QCD: We calculate matrix elements of the axial current for static-light mesons and\nbaryons in lattice QCD with dynamical domain wall fermions. We use partially\nquenched heavy hadron chiral perturbation theory in a finite volume to extract\nthe axial couplings g_1, g_2, and g_3 from the data. These axial couplings\nallow the prediction of strong decay rates and enter chiral extrapolations of\nmost lattice results in the b sector. Our calculations are performed with two\nlattice spacings and with pion masses down to 227 MeV."
    },
    {
        "anchor": "Lattice Calculation of Glueball Matrix Elements: Matrix elements of the form $ <0| Tr \\; g^{2}GG |G> $ are calculated using\nthe lattice QCD Monte Carlo method. Here, $|G>$ is a glueball state with\nquantum numbers $ 0^{++}$, $ 2^{++}$, $ 0^{-+}$ and $G$ is the gluon field\nstrength operator. The matrix elements are obtained from the hybrid correlation\nfunctions of the fuzzy and plaquette operators performed on the $12^{4}$ and\n$14^{4}$ lattices at $\\beta = 5.9 $ and $5.96$ respectively. These matrix\nelements are compared with those from the QCD sum rules and the tensor meson\ndominance model. They are the non-perturbative matrix elements needed in the\ncalculation of the partial widths of $J/\\Psi$ radiative decays into glueballs.",
        "positive": "Results from a study of the Nambu--Jona-Lasinio model on the lattice: The main results of our analysis of the two flavor Nambu--Jona-Lasinio model\nwith $SU(2) \\times SU(2)$ chiral symmetry on the four--dimensional hypercubic\nlattice with naive and Wilson fermions are presented. Large $N$ techniques and\nnumerical simulations are used to study various properties of the model. The\nscalar and pseudoscalar spectrum, the approach to the continuum and chiral\nlimits, the size of the $1/N$ corrections, and the effects of the zero momentum\nfermionic modes on finite lattices are studied. Also, some interesting\nobservations are made by viewing the model as an embedding theory of the Higgs\nsector."
    },
    {
        "anchor": "Lattice QCD spectroscopy for hadronic CP violation: The interpretation of nuclear electric dipole moment (EDM) experiments is\nclouded by large theoretical uncertainties associated with nonperturbative\nmatrix elements. In various beyond-the-Standard Model scenarios nuclear and\ndiamagnetic atomic EDMs are expected to be dominated by CP-violating\npion-nucleon interactions that arise from quark chromo-electric dipole moments.\nThe corresponding CP-violating pion-nucleon coupling strengths are, however,\npoorly known. In this work we propose a strategy to calculate these couplings\nby using spectroscopic lattice QCD techniques. Instead of directly calculating\nthe pion-nucleon coupling constants, a challenging task, we use chiral symmetry\nrelations that link the pion-nucleon couplings to nucleon sigma terms and mass\nsplittings that are significantly easier to calculate. In this work, we show\nthat these relations are reliable up to next-to-next-to-leading order in the\nchiral expansion in both SU(2) and SU(3) chiral perturbation theory. We\nconclude with a brief discussion about practical details regarding the required\nlattice QCD calculations and the phenomenological impact of an improved\nunderstanding of CP-violating matrix elements.",
        "positive": "Isotropic and Anisotropic Lattice Spacing Corrections for I=2 pi-pi\n  Scattering from Effective Field Theory: The calculation of the finite lattice spacing corrections for I=2 pi-pi\nscattering is carried out for isotropic and anisotropic Wilson lattice actions.\nPion masses and decay constants are also determined in this context. These\nresults correct the phase shift calculated from the lattice, which is connected\nto the scattering length and effective range in this low energy scattering\nprocess. When in terms of the lattice-physical parameters for either Wilson\naction, these lattice spacing effects first appear at the next-to-leading order\ncounter-terms."
    },
    {
        "anchor": "Dynamical generation of a gauge symmetry in the Double-Exchange model: It is shown that a bosonic formulation of the double-exchange model, one of\nthe classical models for magnetism, generates dynamically a gauge-invariant\nphase in a finite region of the phase diagram. We use analytical methods, Monte\nCarlo simulations and Finite-Size Scaling analysis. We study the transition\nline between that region and the paramagnetic phase. The numerical results show\nthat this transition line belongs to the Universality Class of the\nAntiferromagnetic RP(2) model. The fact that one can define a Universality\nClass for the Antiferromagnetic RP(2) model, different from the one of the O(N)\nmodels, is puzzling and somehow contradicts naive expectations about\nUniversality.",
        "positive": "On the semimetal-insulator transition and Lifshitz transition in\n  simulations of mono-layer graphene: We report on the status of ongoing Hybrid-Monte-Carlo simulations of the\ntight-binding model of mono-layer graphene. We present results concerning the\nsemimetal-insulator phase transition, whereby two-body interactions are modeled\nby a partially screened Coulomb potential which takes into account screening by\nelectrons in the lower $\\sigma$-orbitals. We obtain evidence that finite-size\neffects may still be present in the current estimate of the critical coupling\nstrength $\\alpha_C$, which was previously extracted from simulations on\nlattice-sizes up to $N_x=N_y=18$. We also present preliminary results\nconcerning the Neck-disrupting Lifshitz transition which occurs at finite\nFermion-density in the limit of vanishing two-body interactions. A sign-problem\nis circumvented by using a spin-dependent chemical potential in our\nsimulations."
    },
    {
        "anchor": "Calculating Quark Number Susceptibilities with Domain-Wall Fermions: We present results from calculations of different quark number and hadronic\nsusceptibilities on 2+1-flavor dynamical domain wall ensembles. We find that\nthe iso-spin and electric charge susceptibilities are especially well suited to\ndetermine the transition temperature, as these quantities show only small\nstatistical errors. Moreover, the transition values of the coupling obtained\nfrom iso-spin and electrical charge susceptibilities are in good agreement with\nthe one obtained from the chiral condensate.",
        "positive": "Cold Atom Quantum Simulator for String and Hadron Dynamics in\n  Non-Abelian Lattice Gauge Theory: We propose an analog quantum simulator for simulating real time dynamics of\n$(1+1)$-d non-Abelian gauge theory well within the existing capacity of\nultracold atom experiments. The scheme calls for the realization of a two-state\nultracold fermionic system in a 1-dimensional bipartite lattice, and the\nobservation of subsequent tunneling dynamics. Being based on novel loop string\nhadron formalism of SU(2) lattice gauge theory, this simulation technique is\ncompletely SU(2) invariant and simulates accurate dynamics of physical\nphenomena such as string breaking and/or pair production. The scheme is\nscalable, and particularly effective in simulating the theory in weak coupling\nregime, and also bulk limit of the theory in strong coupling regime up to\ncertain approximations. This paper also presents a numerical benchmark\ncomparison of exact spectrum and real time dynamics of lattice gauge theory to\nthat of the atomic Hamiltonian with experimentally realizable range of\nparameters."
    },
    {
        "anchor": "Fermion Interactions in the Wilson Yukawa Approach for Lattice Chiral\n  Gauge Theories: We consider fermion-gauge couplings in the Wilson-Yukawa approach for lattice\nchiral gauge theories. At the leading order of a fermionic hopping parameter\nexpansion we find that the fermion-gauge coupling has a chiral and tree-like\nstructure. We argue that this fermion-gauge coupling remains non-zero in the\ncontinuum limit taken in the Higgs phase. Possible fermion-scalar couplings in\nthis approach are considered. We also evaluate the fermion interaction with an\nexternal gauge field in the slightly modified model and show that it has a\nchiral structure in general.",
        "positive": "Density of States of the lattice Schwinger model: Using a recently introduced tensor network method, we study the density of\nstates of the lattice Schwinger model, a standard testbench for lattice gauge\ntheory numerical techniques, but also the object of recent experimental quantum\nsimulations. We identify regimes of parameters where the spectrum appears to be\nsymmetric and displays the expected continuum properties even for finite\nlattice spacing and number of sites. However, we find that for moderate system\nsizes and lattice spacing of $ga\\sim O(1)$, the spectral density can exhibit\nvery different properties with a highly asymmetric form. We also explore how\nthe method can be exploited to extract thermodynamic quantities."
    },
    {
        "anchor": "Calculation and Interpretation of Hadron Correlation Functions in\n  Lattice QCD: Several new developments in the calculation and interpretation of hadron\ndensity-density correlation functions are presented. The asymptotic behavior of\ncorrelation functions is determined from a tree diagram path integral. A method\nis developed to use this behavior to correct for leading image contributions on\na finite periodic spatial lattice and to correct for the finite temporal extent\nof the lattice. Equal time correlation functions are shown to determine a sum\nof the ground state rms radius plus a polarization correction, and it is shown\nhow to extract the hadron polarizability from unequal time correlation\nfunctions. Image-corrected correlation functions calculated in quenched lattice\nQCD are presented and used to determine the size of the pion and nucleon.",
        "positive": "A New Strategy for the Lattice Evaluation of the Leading Order Hadronic\n  Contribution to $(g-2)_\u03bc$: A reliable evaluation of the integral giving the hadronic vacuum polarization\ncontribution to the muon anomalous magnetic moment should be possible using a\nsimple trapezoid-rule integration of lattice data for the subtracted\nelectromagnetic current polarization function in the Euclidean momentum\ninterval $Q^2>Q^2_{min}$, coupled with an $N$-parameter Pad\\'e or other\nrepresentation of the polarization in the interval $0<Q^2<Q^2_{min}$, for\nsufficiently high $Q^2_{min}$ and sufficiently large $N$. Using a physically\nmotivated model for the $I=1$ polarization, and the covariance matrix from a\nrecent lattice simulation to generate associated fake \"lattice data,\" we show\nthat systematic errors associated with the choices of $Q^2_{min}$ and $N$ can\nbe reduced to well below the 1% level for $Q^2_{min}$ as low as 0.1 GeV$^2$ and\nrather small $N$. For such low $Q^2_{min}$, both an NNLO chiral representation\nwith one additional NNNLO term and a low-order polynomial expansion employing a\nconformally transformed variable also provide representations sufficiently\naccurate to reach this precision for the low-$Q^2$ contribution. Combined with\nstandard techniques for reducing other sources of error on the lattice\ndetermination, this hybrid strategy thus looks to provide a promising approach\nto reaching the goal of a sub-percent precision determination of the hadronic\nvacuum polarization contribution to the muon anomalous magnetic moment on the\nlattice."
    },
    {
        "anchor": "New Physics Searches from Nucleon Matrix Elements in Lattice QCD: In this paper we review recent progress in hadron structure using lattice QCD\nsimulations, with main focus in the evaluation of nucleon matrix elements. We\nhighlight developments that may guide new Physics searches, such as the scalar\nand tensor charges, as well as, the neutron electric dipole moment.",
        "positive": "Introducing Dynamical Triangulations to the Type IIB Superstrings: In order to consider non-perturbative effects of superstrings, we try to\napply dynamical triangulations to the type IIB superstrings. The discretized\naction is constructed from the type IIB matrix model proposed as a constructive\ndefinition of superstring theory. The action has the local N=2 supersymmetry\nexplicitly, and has no extra fermionic degrees of freedom. We evaluate the\npartition function for some simple configurations and discuss constraints\nrequired from the finiteness of partition functions."
    },
    {
        "anchor": "Staggered Chiral Perturbation Theory for Heavy-Light Mesons: We incorporate heavy-light mesons into staggered chiral perturbation theory,\nworking to leading order in 1/m_Q, where m_Q is the heavy quark mass. At first\nnon-trivial order in the chiral expansion, staggered taste violations affect\nthe chiral logarithms for heavy-light quantities only through the light meson\npropagators in loops. There are also new analytic contributions coming from\nadditional terms in the Lagrangian involving heavy-light and light mesons.\nUsing this heavy-light staggered chiral perturbation theory, we perform the\none-loop calculation of the B (or D) meson leptonic decay constant in the\npartially quenched and full QCD cases. In our treatment, we assume the validity\nboth of the \"fourth root trick\" to reduce four staggered tastes to one, and of\nthe prescription to represent this trick in the chiral theory by insertions of\nfactors of 1/4 for each sea quark loop.",
        "positive": "G2 gauge theories: QCD can be formulated using any gauge group. One particular interesting\nchoice is to replace SU(3) by the exceptional group G2. Conceptually, this\ngroup is the simplest group with a trivial center. It thus permits to study the\nconjectured relevance of center degrees of freedom for QCD. Practically, since\nall its representation are real, it is possible to perform lattice simulations\nfor this theory also at finite baryon densities. It is thus an excellent\nenvironment to test methods and to investigate general properties of gauge\ntheories at finite densities. We review the status of our understanding of\ngauge theories with the gauge group G2, including Yang-Mills theory,\nYang-Mills-Higgs theory, and QCD both in the vacuum and in the phase diagram."
    },
    {
        "anchor": "High-density QCD: the effects of strangeness: I discuss the zero temperature phase diagram of QCD, as a function of baryon\ndensity and strange quark mass. The noteworthy points are that at sufficiently\nhigh density chiral symmetry is always restored, and at low strange quark mass\nthere need be no phase transition between nuclear matter and quark matter. I\ncomment on the possibility that introducing a strange quark may make it easier\nto see finite-density physics on the lattice.",
        "positive": "Long-distance contribution to $\u03b5_K$ from lattice QCD: A lattice QCD approach to the calculation of the long-distance contributions\nto $\\epsilon_K$ is presented. This parameter describes indirect CP violation in\n$K\\to\\pi\\pi$ decay. While the short-distance contribution to $\\epsilon_K$ can\nbe accurately calculated in terms of standard model parameters and a single\nhadronic matrix element, $B_K$, there is a long-distance part which is\nestimated to be approximately $5\\%$ of the total and is more difficult to\ndetermine. A method for determining this small but phenomenologically important\ncontribution to $\\epsilon_K$ using lattice QCD is proposed and a complete\nexploratory calculation of the contribution is presented. This exploratory\ncalculation uses an unphysical light quark mass corresponding to a 339 MeV pion\nmass and an unphysical charm quark mass of 968 MeV, expressed in the\n$\\overline{\\mathrm{MS}}$ scheme at 2 GeV. This calculation demonstrates that\nfuture work should be able to determine this long-distance contribution from\nfirst principles with a controlled error of 10\\% or less."
    },
    {
        "anchor": "RI/MOM and RI/SMOM renormalization of overlap quark bilinears on domain\n  wall fermion configurations: Renormalization constants (RCs) of overlap quark bilinear operators on\n2+1-flavor domain wall fermion configurations are calculated by using the\nRI/MOM and RI/SMOM schemes. The scale independent RC for the axial vector\ncurrent is computed by using a Ward identity. Then the RCs for the quark field\nand the vector, tensor, scalar and pseudoscalar operators are calculated in\nboth the RI/MOM and RI/SMOM schemes. The RCs are converted to the\n$\\overline{\\rm MS}$ scheme and we compare the numerical results from using the\ntwo intermediate schemes. The lattice size is $48^3\\times96$ and the inverse\nspacing $1/a = 1.730(4) {\\rm~GeV}$.",
        "positive": "The QCD Phase Transition Region with Domain Wall Quarks: Results will be presented from a study of the QCD transition region using 2+1\nflavors of fermions and a dislocation suppressing gauge action on a lattice\nwith temporal extent of 8 and spatial extent 16 (1.9 - 2.7 fm). A series of\ntemperatures from 140 through 200 MeV, separated by 10 MeV have been studied.\nAll the simulations lie on a line of constant physics with 200 MeV pions,\nrealized using domain wall fermion, a chirally symmetric fermion formulation.\nThe chiral condensates, susceptibility, anomalous symmetry breaking and a\ndetailed study of the Dirac spectrum will be described and compared with\nearlier staggered results."
    },
    {
        "anchor": "The role of multigrid algorithms for LQCD: We report on the first successful QCD multigrid algorithm which demonstrates\nconstant convergence rates independent of quark mass and lattice volume for the\nWilson Dirac operator. The new ingredient is the adaptive method for\nconstructing the near null space on which the coarse grid multigrid Dirac\noperator acts. In addition we speculate on future prospects for extending this\nalgorithm to the Domain Wall and Staggered discretizations, its exceptional\nsuitability for high performance GPU code and its potential impact on\nsimulations at the physical pion mass.",
        "positive": "Noncompact Lattice Simulations of SU(2) Gauge Theory: Wilson loops have been measured at strong coupling, $\\beta=0.5$, on a $12^4$\nlattice in noncompact simulations of pure SU(2) without gauge fixing. There is\nno sign of quark confinement."
    },
    {
        "anchor": "Form factors for rare B decays: strategy, methodology, and numerical\n  study: We investigate the combined use of moving NRQCD and stochastic sources in\nlattice calculations of form factors describing rare B and B_s decays. Moving\nNRQCD leads to a reduction of discretisation errors compared to standard NRQCD.\nStochastic sources are tested for reduction of statistical errors.",
        "positive": "From square plaquettes to triamond lattices for SU(2) gauge theory: Lattice gauge theory should be able to address significant new scientific\nquestions when implemented on quantum computers. In practice, error-mitigation\ntechniques have already allowed encouraging progress on small lattices. In this\nwork we focus on a truncated version of SU(2) gauge theory, which is a familiar\nnon-Abelian step toward quantum chromodynamics. First, we demonstrate effective\nerror mitigation for imaginary time evolution on a lattice having two square\nplaquettes, obtaining the ground state using an IBM quantum computer and\nobserving that this would have been impossible without error mitigation. Then\nwe propose the triamond lattice as an expedient approach to lattice gauge\ntheories in three spatial dimensions, deriving the Hamiltonian and obtaining\nenergy eigenvalues and eigenstates from a noiseless simulator for a\nthree-dimensional unit cell."
    },
    {
        "anchor": "The Gluon Propagator without lattice Gribov copies: We study the gluon propagator in quenched lattice QCD using the Laplacian\ngauge which is free of lattice Gribov copies. We compare our results with those\nobtained in the Landau gauge on the lattice, as well as with various\napproximate solutions of the Dyson Schwinger equations. We find a finite value\n$\\sim (445 \\rm{MeV})^{-2}$ for the renormalized zero-momentum propagator\n(taking our renormalization point at 1.943 GeV), and a pole mass $\\sim 640 \\pm\n140$ MeV.",
        "positive": "Flavor physics with $\u039b_b$ baryons: At the LHC, bottom baryons are being produced in unprecedented quantities,\nwhich opens up a new field for flavor physics. For example, the decay\n$\\Lambda_b \\to p \\mu^- \\bar{\\nu}$ can be used to obtain a novel determination\nof the CKM matrix element $|V_{ub}|$, and the decay $\\Lambda_b \\to \\Lambda\n\\mu^+ \\mu^-$ probes the weak interactions at the loop level. The first lattice\ncalculations of the relevant $\\Lambda_b \\to p$ and $\\Lambda_b \\to \\Lambda$ form\nfactors have recently been performed using domain-wall light quarks and static\n$b$ quarks. To further reduce the theoretical uncertainty, one has to go beyond\nthe static approximation. Here I present new calculations of $\\Lambda_b \\to p$,\n$\\Lambda_b \\to \\Lambda$, and $\\Lambda_b \\to \\Lambda_c$ form factors using a\nrelativistic heavy-quark action."
    },
    {
        "anchor": "The Status of D-Theory: Field theories are usually quantized by performing a path integral over\nconfigurations of classical fields. This is the case both in perturbation\ntheory and in Wilson's nonperturbative lattice field theory. D-theory is an\nalternative nonperturbative formulation of field theory in which classical\nfields emerge from the low-energy collective dynamics of discrete quantum\nvariables (quantum spins and their gauge analogs -- quantum links) which\nundergo dimensional reduction. D-theory was developed some time ago as a\ndiscrete approach to U(1) and SU(2) pure gauge theories, extended to SU(N)\ngauge theories and full QCD, and also applied to a variety of other models. On\nthe practical side, D-theory provides a framework for the development of\nefficient numerical methods, such as cluster algorithms. For example, in the\nD-theory formulation of CP(N-1) models one can simulate efficiently at non-zero\nchemical potential or at non-zero vacuum angle theta. On the conceptual side,\nD-theory offers a natural solution for the nonperturbative hierarchy problem of\nchiral symmetry in QCD. We also take a broader nonperturbative view on\nfundamental physics and speculate that D-theory variables -- i.e. quantum spins\nand quantum links -- may be promising candidates for the physical degrees of\nfreedom that Nature has chosen to regularize the standard model physics at\nultra-short distances.",
        "positive": "Partially Quenched Chiral Perturbation Theory to NNLO: This paper summarizes the recent calculations of the masses and decay\nconstants of the pseudoscalar mesons at the two-loop level, or NNLO, in\nPartially Quenched Chiral Perturbation Theory (PQxPT). Possible applications\ninclude chiral extrapolations of Lattice QCD, as well as the determination of\nthe low-energy constants (LEC:s) of QCD."
    },
    {
        "anchor": "Onset Transition to Cold Nuclear Matter from Lattice QCD with Heavy\n  Quarks to $\u03ba^4$: We present results of our ongoing studies of an effective three-dimensional\ntheory of thermal lattice QCD with heavy Wilson quarks. This is done by\ncombined strong coupling and hopping parameter expansions. The full quark\ndeterminant of four dimensional lattice QCD is expanded in orders of the\nhopping parameter $\\kappa$, the dimensional reduction is achieved by\nintegrating over the spatial links. We present the calculation of the effective\ntheory through order $\\kappa^nu^m$ with $n+m=4$. This theory is then used to\nsimulate heavy quarks near the cold and dense limit. For nonzero chemical\npotential the theory suffers from a sign problem, wich is avoided by employing\nstochastical quantisation. Continuum extrapolated results for the onset of\nnuclear matter are shown and the region of convergence of the effective theory\nis discussed.",
        "positive": "Bottom hadron mass splittings in the static limit from 2+1 flavour\n  lattice QCD: Dynamical 2+1 flavour lattice QCD is used to calculate the splittings between\nthe masses of mesons and baryons containing a single static heavy quark and\ndomain-wall light and strange quarks. Our calculations are based on the\ndynamical domain-wall gauge field configurations generated by the RBC and UKQCD\ncollaborations at a spatial volume of (2.7 fm)^3 and a range of quark masses\nwith a lightest value corresponding to a (partially-quenched) pion mass of 275\nMeV. When extrapolated to the physical values of the light quark masses, the\nresults of our calculations are generally in good agreement with experimental\ndeterminations in the bottom sector. However, the static limit splittings\nbetween the Omega_b^- baryon and other bottom hadrons tend to slightly\nunderestimate those obtained using the recent D-zero measurement of the\nOmega_b^-."
    },
    {
        "anchor": "Second order cumulants of conserved charge fluctuations revisited I.\n  Vanishing chemical potentials: We update lattice QCD results for second order cumulants of conserved charge\nfluctuations and correlations at non-zero temperature and vanishing values of\nthe conserved charge chemical potentials. We compare these results to hadron\nresonance gas calculations with and without excluded volume terms as well as\nS-matrix results in the hadronic phase of QCD, and comment on their current\nlimitations. We, furthermore, use these results to characterize thermal\nconditions in the vicinity of the pseudo-critical line of the chiral transition\nin QCD. We argue that the ratio of strange to baryon chemical potentials is a\nrobust observable that, on the one hand, deviates only little from hadron\nresonance gas results, but, on the other hand, is very sensitive to the\nspectrum of strange baryon resonances.",
        "positive": "Numerical Computations in the Worldsheet Formulation: The worldsheet formulation of lattice gauge theories has two appealing\nfeatures: the gauge non-redundancy and the geometrical transparency. Both\nproperties are profitable in order to perform numerical computations. In the\ncase of dynamical fermions this description offers additional advantages. For\ninstance, it does not suffer from the species doubling problem and it involves\nfewer degrees of freedom."
    },
    {
        "anchor": "Expansion Aspect of Color Transparency on the Lattice: The opportunity to observe color transparency (CT) is determined by how\nrapidly a small-sized hadronic wave packet expands. Here we use SU(2) lattice\ngauge theory with Wilson fermions in the quenched approximation to investigate\nthe expansion. The wave packet is modeled by a point hadronic source, often\nused as an interpolating field in lattice calculations. The procedure is to\ndetermine the Euclidean time (t), pion channel, Bethe-Salpeter amplitude\n$\\Psi(r,t)$, and then evaluate $b^2(t)=\\int d^3 r \\Psi(r,t) r^2 sin^2 \\theta\n\\Psi_{\\pi}(r)$. This quantity represents the soft interaction of a small-sized\nwave packet with a pion. The time dependence of $b^2(t)$ is fit as a\nsuperposition of three states, which is found sufficient to reproduce a reduced\nsize wave packet. Using this superposition allows us to make the analytic\ncontinuation required to study the wave packet expansion in real time. We find\nthat the matrix elements of the soft interaction $\\hat b^2$ between the excited\nand ground state decrease rapidly with the energy of the excited state.",
        "positive": "Gauge-fixing approach to lattice chiral gauge theories: We review the status of our recent work on the gauge-fixing approach to\nlattice chiral gauge theories. New numerical results in the reduced version of\na model with a U(1) gauge symmetry are presented which strongly indicate that\nthe factorization of the correlation functions of the left-handed neutral and\nright-handed charged fermion fields, which we established before in\nperturbation theory, holds also nonperturbatively."
    },
    {
        "anchor": "Quantum Behaviour of the Flux Tube: A comparison between QFT predictions\n  and lattice gauge theory simulations: We review some universal features of the colour flux tube of gauge theories\nin the confining phase predicted by the infrared conformal limit of the\nunderlying string theory. In particular we discuss shape effects in Wilson\nloops and rederive in a general way the logarithmic growth of the mean square\nwidth of the flux tube as a function of the interquark separation. Recent data\non three-dimensional Z_2 gauge theory, combined with high precision data on the\ninterface physics of the 3D Ising model fit nicely to this behaviour over a\nrange of more than two orders of magnitude",
        "positive": "Effect of Improving the Lattice Gauge Action on QCD Topology: We use lattice topology as a laboratory to compare the Wilson action (WA)\nwith the Symanzik-Weisz (SW) action constructed from a combination of (1x1) and\n(1x2) Wilson loops, and the estimate of the renormalization trajectory (RT)\nfrom a renormalization group transformation (RGT) which also includes higher\nrepresentations of the (1x1) loop. Topological charges are computed using the\ngeometric (L\\\"uscher's) and plaquette methods on the uncooled lattice, and also\nby using cooling to remove ultraviolet artifacts. We show that as the action\nimproves by approaching the RT, the topological charges for individual\nconfigurations computed using these three methods become more highly\ncorrelated, suggesting that artificial lattice renormalizations to the\ntopological susceptibility can be suppressed by improving the action."
    },
    {
        "anchor": "A Lattice QCD Analysis of the Strangeness Magnetic Moment of the Nucleon: The outcome of the SAMPLE Experiment suggests that the strange-quark\ncontribution to the nucleon magnetic moment, G_M^s(0), may be greater than\nzero. This result is very difficult to reconcile with expectations based on the\nsuccessful baryon magnetic-moment phenomenology of the constituent quark model.\nWe show that careful consideration of chiral symmetry reveals some rather\nunexpected properties of QCD. In particular, it is found that the valence\nu-quark contribution to the magnetic moment of the neutron can differ by more\nthan 50% from its contribution to the Xi^0 magnetic moment. This hitherto\nunforeseen result leads to the value G_M^s(0) = -0.16 +/- 0.18 with a\nsystematic error, arising from the relatively large strange quark mass used in\nexisting lattice calculations, that would tend to shift G_M^s(0) towards small\npositive values.",
        "positive": "The U_A(1) Problem on the Lattice with Ginsparg-Wilson Fermions: We show how it is possible to give a precise and unambiguous implementation\nof the Witten--Veneziano formula for the eta' mass on the lattice, which looks\nlike the formal continuum one, if the expression of the topological charge\ndensity operator, suggested by fermions obeying the Ginsparg--Wilson relation,\nis employed. By using recent numerical results from simulations with overlap\nfermions in 2 (abelian Schwinger model) and 4 (QCD) dimensions, one obtains\nvalues for the mass of the lightest pseudo-scalar flavour-singlet state that\nagree within errors with theoretical expectations and experimental data,\nrespectively."
    },
    {
        "anchor": "Percolating cluster of center vortices and confinement: We study the role of percolating clusters of center vortices in\nconfigurations of an Ising gauge theory in 3D. It is known that low energy\nfeatures of gauge theories can be described in terms of an ``effective string\npicture'', and that confinement properties are associated with topologically\nnon-trivial configurations. We focus our attention upon percolating clusters of\ncenter vortices, and present numerical evidence for the fact that these objects\nplay a preminent role in confinement phenomenon, since their removal sweeps off\nconfinement altogether. Moreover, numerical simulations show that the string\nfluctuations, and in particular the Luescher term, are completely encoded in\nthe percolating cluster.",
        "positive": "Quarkonium correlators and spectral functions at zero and finite\n  temperature from Fermilab action: We study charmonium and bottomonium systems at zero and finite temperatures\nusing Lattice QCD with Fermilab action on anisotropic lattices."
    },
    {
        "anchor": "A lattice approach to QCD in the chiral regime: Non-perturbative lattice studies of QCD in the chiral thermodynamic regime,\nwhere chiral symmetry is spontaneously broken, require to deal with almost\nquark zero modes in a theoretically clean and computationally efficient way. We\ndiscuss the basic features and some realistic tests of a formulation, known as\nlattice tmQCD, that fulfills these requirements. Based on a talk given by R.\nFrezzotti at the conference HEP2001 (Budapest, July 2001)",
        "positive": "Gluon Propagators and Confinement: We present SU(3) gluon propagators calculated on 48*48*48*N_t lattices at\nbeta=6.8 where N_t=64 (corresponding the confinement phase) and N_t=16\n(deconfinement) with the bare gauge parameter,alpha, set to be 0.1. In order to\navoid Gribov copies, we employ the stochastic gauge fixing algorithm. Gluon\npropagators show quite different behavior from those of massless gauge fields:\n(1) In the confinement phase, G(t) shows massless behavior at small and large\nt, while around 5<t<15 it behaves as massive particle, and (2) effective mass\nobserved in G(z) becomes larger as z increases. (3) In the deconfinement phase,\nG(z) shows also massive behavior but effective mass is less than in the\nconfinement case. In all cases, slope masses are increasing functions of t or\nz, which can not be understood as addtional physical poles."
    },
    {
        "anchor": "Aoki Phases in Staggered-Wilson Fermions: We investigate the parity-broken phase (Aoki phase) for staggered-Wilson\nfermions by using the Gross-Neveu model and the strong-coupling lattice QCD. In\nthe both cases the gap equations indicate the parity-broken phase exists and\nthe pion becomes massless on the phase boundaries. We also show we can take the\nchiral and continuum limit in the Gross-Neveu model by tuning mass and\ngauge-coupling parameters. This supports the idea that the staggered-Wilson\nfermions can be applied to the lattice QCD simulation by taking a chiral limit,\nas with Wilson fermions.",
        "positive": "Charged multi-hadron systems in lattice QCD+QED: Systems with the quantum numbers of up to twelve charged and neutral\npseudoscalar mesons, as well as one-, two-, and three-nucleon systems, are\nstudied using dynamical lattice quantum chromodynamics and quantum\nelectrodynamics (QCD+QED) calculations and effective field theory. QED effects\non hadronic interactions are determined by comparing systems of charged and\nneutral hadrons after tuning the quark masses to remove strong isospin breaking\neffects. A non-relativistic effective field theory, which perturbatively\nincludes finite-volume Coulomb effects, is analyzed for systems of multiple\ncharged hadrons and found to accurately reproduce the lattice QCD+QED results.\nQED effects on charged multi-hadron systems beyond Coulomb photon exchange are\ndetermined by comparing the two- and three-body interaction parameters\nextracted from the lattice QCD+QED results for charged and neutral multi-hadron\nsystems."
    },
    {
        "anchor": "Lattice investigation of heavy meson interactions: We report on a lattice investigation of heavy meson interactions and of\ntetraquark candidates with two very heavy quarks. These two quarks are treated\nin the static limit, while the other two are up, down, strange or charm quarks\nof finite mass. Various isospin, spin and parity quantum numbers are\nconsidered.",
        "positive": "Meson spectrum in the large $N$ limit: We present the result of our computation of the lowest lying meson masses for\nSU(N) gauge theory in the large $N$ limit (with $N_f/N\\longrightarrow 0$). The\nfinal values are given in units of the square root of the string tension, and\nwith errors which account for both statistical and systematic errors. By using\n4 different values of the lattice spacing we have seen that our results scale\nproperly. We have studied various values of $N$ (169, 289 and 361) to monitor\nthe N-dependence of the most sensitive quantities. Our methodology is based\nupon a first principles approach (lattice gauge theory) combined with large $N$\nvolume independence. We employed both Wilson fermions and twisted mass fermions\nwith maximal twist. In addition to masses in the pseudoscalar, vector, scalar\nand axial vector channels, we also give results on the pseudoscalar decay\nconstant and various remormalization factors."
    },
    {
        "anchor": "The electromagnetic form factor of the pion in two-flavour lattice QCD: We present the current status of our lattice calculation of the\nelectromagnetic form factor of the pion with two flavours of non-perturbatively\nO(a)-improved Wilson fermions. Using twisted boundary conditions and stochastic\nsources we obtain accurate results with a fine momentum resolution near\n$q^2=0$. This enables the computation of the charge radius without model\ndependence. The ensembles cover various lattice spacings and pion masses,\nranging down to 250 MeV. This allows to compare the data to continuum chiral\nperturbation theory to NNLO including corrections of finite lattice spacing to\nperform a simultaneous chiral and continuum extrapolation. An estimate for the\nsystematic error resulting from the extrapolation can be obtained by looking at\nthe spread of results obtained from other functional forms such as polynomials.",
        "positive": "SU(3) Lattice Gauge Theory With Adjoint Action At Nonzero Temperature: We study the thermal phase diagram of pure SU(3) gauge theory with\nfundamental and adjoint couplings. We improve previous estimates of the\nposition of the bulk transition line and determine the thermal deconfinement\ntransition lines for $N_t=2,4,6,$ and 8. For $N_t > 4$ the deconfinement\ntransition line splits cleanly away from the bulk transition line. With\nincreasing $N_t$ the thermal deconfinement transition lines shift to\nincreasingly weaker coupling, joining onto the bulk transition line at\nincreasingly larger $\\beta_a$ in a pattern consistent with the usual\nuniversality picture of lattice gauge theories."
    },
    {
        "anchor": "Applying Complex Langevin to Lattice QCD at finite $\u03bc$: We continue our simulations of lattice QCD at finite quark-number chemical\npotential, $\\mu$, using the complex-Langevin equation (CLE) with gauge-cooling\nand adaptive updating. The CLE is used because QCD at finite finite $\\mu$ has a\ncomplex fermion determinant, which prevents use of standard simulation methods.\nSimulations using the standard lattice action show a transition from hadronic\nto nuclear matter for $\\mu < m_\\pi/2$ rather than the expected $\\mu \\approx\nm_N/3$. This suggests that the CLE is being influenced by the phase-quenched\ntheory, which has a transition at $\\mu = m_\\pi/2$. We are therefore performing\nCLE simulations with a new action which includes an irrelevant chiral 4-fermion\ninteraction. This separates the physics at energies of order of the pion mass\nand smaller from that at energies of the other hadrons. In doing this, it\nbreaks the extended symmetry of the phase-quenched theory over that of the full\ntheory, raising the masses of the extra pion-like excitations consisting of a\nquark and a conjugate quark, which could otherwise produce such an anomalous\ntransition. Our preliminary CLE simulations using massless quarks, so that\n$m_\\pi=0$, show no transition at $\\mu=m_\\pi/2=0$, but do show a transition at\nan appreciably higher value of $\\mu$. It remains to be seen if this transition\nis near to $m_N/3$.",
        "positive": "Topological tunneling with Dynamical overlap fermions: Tunneling between different topological sectors with dynamical chiral\nfermions is difficult because of a poor mass scaling of the pseudo-fermion\nestimate of the determinant. For small fermion masses it is virtually\nimpossible using standard methods. However, by projecting out the small Wilson\neigenvectors from the overlap operator, and treating the correction determinant\nexactly, we can significantly increase the rate of topological sector tunneling\nand reduce substantially the auto-correlation time. We present and compare a\nnumber of different approaches, and advocate a method which allows topological\ntunneling even at low mass with little addition to the computational cost."
    },
    {
        "anchor": "Thermodynamics of SU(3) Gauge Theory in 2 + 1 Dimensions: The pressure, and the energy and entropy densities are determined for the\nSU(3) gauge theory in $2 + 1$ dimensions from lattice Monte Carlo calculations\nin the interval $0.6 \\leq T/T_c \\leq 15$. The finite temperature lattices\nsimulated have temporal extent $N_\\tau = 2, 4, 6$ and 8, and spatial volumes\n$N_S^2$ such that the aspect ratio is $N_S/N_\\tau = 8$. To obtain the\nthermodynamical quantities, we calculate the averages of the temporal\nplaquettes $P_\\tau$ and the spatial plaquettes $P_S$ on these lattices. We also\nneed the zero temperature averages of the plaquettes $P_0$, calculated on\nsymmetric lattices with $N_\\tau = N_S$. We discuss in detail the finite size\n($N_S$-dependent) effects. These disappear exponentially. For the zero\ntemperature lattices we find that the coefficient of $N_S$ in the exponent is\nof the order of the glueball mass. On the finite temperature lattices it lies\nbetween the two lowest screening masses. For the aspect ratio equal to eight,\nthe systematic errors coming from the finite size effects are much smaller than\nour statistical errors. We argue that in the continuum limit, at high enough\ntemperature, the pressure can be parametrized by the very simple formula\n$p=a-bT_c/T$ where $a$ and $b$ are two constants. Using the thermodynamical\nidentities for a large homogeneous system, this parametrization then determines\nthe other thermodynamical variables in the same temperature range.",
        "positive": "Regulated chiral gauge theories: Noncompact chiral abelian gauge theories are defined on the lattice using the\noverlap formalism. The main definitions are presented, the role of anomaly\ncancelation is discussed, and the triviality issue in four dimensions is\nexplained."
    },
    {
        "anchor": "Melting Instantons, Domain Walls, and Large N: Monte Carlo studies of $CP^{N-1}$ sigma models have shown that the structure\nof topological charge in these models undergoes a sharp transition at\n$N=N_c\\approx 4$. For $N<N_c$ topological charge is dominated by small\ninstantons, while for $N>N_c$ it is dominated by extended, thin,\n1-dimensionally coherent membranes of topological charge, which can be\ninterpreted as domain walls between discrete quasi-stable vacua. These vacua\ndiffer by a unit of background electric flux. The transition can be identified\nas the delocalization of topological charge, or \"instanton melting,\" a\nphenomenon first suggested by Witten to resolve the conflict between instantons\nand large $N$ behavior. Implications for $QCD$ are discussed.",
        "positive": "Computing hybrid static potentials at short quark-antiquark separations\n  from fine lattices in $SU(3)$ Yang-Mills theory: We compute hybrid static potentials in $SU(3)$ lattice Yang-Mills theory at\nshort quark-antiquark separations using four different small lattice spacings\nas small as $0.04\\,\\text{fm}$. The resulting static potentials are important,\ne.g. when studying heavy hybrid mesons in the Born-Oppenheimer approximation.\nWe also discuss and exclude possible systematic errors from topological\nfreezing, the finite lattice volume and glueball decays."
    },
    {
        "anchor": "A calculation of the gauge anomaly with the chiral overlap operator: We investigate the property of the effective action with the chiral overlap\noperator, which was derived by Grabowska and Kaplan. They proposed a lattice\nformulation of four-dimensional chiral gauge theory, which is derived from\ntheir domain-wall formulation. In this formulation, an extra dimension is\nintroduced and the gauge field along the extra dimension is evolved by the\ngradient flow. The chiral overlap operator satisfies the Ginsparg-Wilson\nrelation and only depends on the gauge fields on the two boundaries. In this\npaper, we start from the arbitrary even-dimensional chiral overlap operator. We\ntreat the gauge fields on the two boundaries independently, and derive the\ngeneral expression to calculate the gauge anomaly with the chiral overlap\noperator in the continuum limit. As a result, we show that the gauge anomalies\nwith the chiral overlap operator in two, four, and six dimensions in the\ncontinuum limit is equivalent to those known in the continuum theory up to\ntotal derivatives.",
        "positive": "A lattice NRQCD computation of the bag parameters for $\u0394B$ = 2\n  operators: We present an update of our NRQCD calculation of $B_B$ at $\\beta$=5.9 with\nincreased statistics. We also discuss a calculation of $B_S$, which is relevant\nto the width difference in the $B_s-\\bar{B}_s$ mixing."
    },
    {
        "anchor": "Superconductivity and Chiral Symmetry Breaking with Fermion Clusters: Cluster variables have recently revolutionized numerical work in certain\nmodels involving fermionic variables. This novel representation of fermionic\npartition functions is continuing to find new applications. After describing\nresults from a study of a two dimensional Hubbard type model that confirm a\nsuperconducting transition in the Kosterlitz-Thouless universality class, we\nshow how a cluster type algorithm can be devised to study the chiral limit of\nstrongly coupled lattice gauge theories with staggered fermions.",
        "positive": "An estimate of the hadronic vacuum polarization disconnected\n  contribution to the anomalous magnetic moment of the muon from lattice QCD: The quark-line disconnected diagram is a potentially important ingredient in\nlattice QCD calculations of the hadronic vacuum polarization contribution to\nthe anomalous magnetic moment of the muon. It is also a notoriously difficult\none to evaluate. Here, for the first time, we give an estimate of this\ncontribution based on lattice QCD results that have a statistically significant\nsignal, albeit at one value of the lattice spacing and an unphysically heavy\nvalue of the $u/d$ quark mass. We use HPQCD's method of determining the\nanomalous magnetic moment by reconstructing the Adler function from\ntime-moments of the current-current correlator at zero spatial momentum. Our\nresults lead to a total (including $u$, $d$ and $s$ quarks) quark-line\ndisconnected contribution to $a_{\\mu}$ of $-0.15\\%$ of the $u/d$ hadronic\nvacuum polarization contribution with an uncertainty which is 1\\% of that\ncontribution."
    },
    {
        "anchor": "Improved Perturbation Theory for Improved Lattice Actions: We study a systematic improvement of perturbation theory for gauge fields on\nthe lattice; the improvement entails resumming, to all orders in the coupling\nconstant, a dominant subclass of tadpole diagrams.\n  This method, originally proposed for the Wilson gluon action, is extended\nhere to encompass all possible gluon actions made of closed Wilson loops; any\nfermion action can be employed as well. The effect of resummation is to replace\nvarious parameters in the action (coupling constant, Symanzik coefficients,\nclover coefficient) by ``dressed'' values; the latter are solutions to certain\ncoupled integral equations, which are easy to solve numerically.\n  Some positive features of this method are: a) It is gauge invariant, b) it\ncan be systematically applied to improve (to all orders) results obtained at\nany given order in perturbation theory, c) it does indeed absorb in the dressed\nparameters the bulk of tadpole contributions.\n  Two different applications are presented: The additive renormalization of\nfermion masses, and the multiplicative renormalization Z_V (Z_A) of the vector\n(axial) current. In many cases where non-perturbative estimates of\nrenormalization functions are also available for comparison, the agreement with\nimproved perturbative results is significantly better as compared to results\nfrom bare perturbation theory.",
        "positive": "Review of lattice results concerning low-energy particle physics: We review lattice results related to pion, kaon, D- and B-meson physics with\nthe aim of making them easily accessible to the particle physics community.\nMore specifically, we report on the determination of the light-quark masses,\nthe form factor f+(0), arising in the semileptonic K -> pi transition at zero\nmomentum transfer, as well as the decay constant ratio fK/fpi and its\nconsequences for the CKM matrix elements Vus and Vud. Furthermore, we describe\nthe results obtained on the lattice for some of the low-energy constants of\nSU(2)LxSU(2)R and SU(3)LxSU(3)R Chiral Perturbation Theory. We review the\ndetermination of the BK parameter of neutral kaon mixing as well as the\nadditional four B parameters that arise in theories of physics beyond the\nStandard Model. The latter quantities are an addition compared to the previous\nreview. For the heavy-quark sector, we provide results for mc and mb (also new\ncompared to the previous review), as well as those for D- and B-meson decay\nconstants, form factors, and mixing parameters. These are the heavy-quark\nquantities most relevant for the determination of CKM matrix elements and the\nglobal CKM unitarity-triangle fit. Finally, we review the status of lattice\ndeterminations of the strong coupling constant alpha_s."
    },
    {
        "anchor": "Potential description of charmonium and charmed-strange mesons from\n  lattice QCD: We present spin-independent and spin-spin interquark potentials for the\ncharmonium and charmed-strange mesons, which are calculated in 2+1 flavor\nlattice QCD simulations using the PACS-CS gauge configurations generated at the\nlightest pion mass ($M_\\pi \\approx 156(7)$~MeV) with a lattice cutoff of\n$a^{-1}\\approx 2.2$ GeV and a spatial volume of $(3~{\\rm fm})^3$. For the charm\nquark, we use a relativistic heavy quark (RHQ) action with fine tuned RHQ\nparameters, which closely reproduce both the experimental spin-averaged mass\nand hyper-fine splitting of the $1S$ charmonium. The interquark potential and\nthe quark kinetic mass, both of which are key ingredients within the potential\ndescription of heavy-heavy and heavy-light mesons, are determined from the\nequal-time Bethe-Salpeter (BS) amplitude. The charmonium potentials are\nobtained from the BS wave function of $1S$ charmonia ($\\eta_c$ and $J/\\psi$\nmesons), while the charmed-strange potential are calculated from the $D_s$ and\n$D_s^{\\ast}$ heavy-light mesons. We then use resulting potentials and quark\nmasses as purely theoretical inputs so as to solve the nonrelativistic\nSchr\\\"odinger equation for calculating accessible energy levels of charmonium\nand charmed-strange mesons without unknown parameters. The resultant spectra\nbelow the $D\\bar{D}$ and $DK$ thresholds excellently agree with\nwell-established experimental data.",
        "positive": "Nucleon electromagnetic form factors using lattice simulations at the\n  physical point: We present results for the nucleon electromagnetic form factors using an\nensemble of maximally twisted mass clover-improved fermions with pion mass of\nabout 130 MeV. We use multiple sink-source separations and three analysis\nmethods to probe ground-state dominance. We evaluate both the connected and\ndisconnected contributions to the nucleon matrix elements. We find that the\ndisconnected quark loop contributions to the isoscalar matrix elements are\nsmall, giving an upper bound of up to 2$\\%$ of the connected contribution and\nsmaller than its statistical error. We present results for the isovector and\nisoscalar electric and magnetic Sachs form factors and the corresponding proton\nand neutron form factors. By fitting the momentum dependence of the form\nfactors to a dipole form or to the z-expansion we extract the nucleon electric\nand magnetic radii, as well as, the magnetic moment. We compare our results to\nexperiment as well as to other recent lattice QCD calculations."
    },
    {
        "anchor": "Lattice String Field Theory: String field theory is a candidate for a full non-perturbative definition of\nstring theory. We aim to define string field theory on a space-time lattice to\ninvestigate its behaviour at the quantum level. Specifically, we look at string\nfield theory in a one dimensional linear dilaton background. We report the\nfirst results of our simulations.",
        "positive": "Symmetries of temporal correlators and the nature of hot QCD: The temperature of the chiral restoration phase transition at 130 MeV as well\nas the temperature of the center symmetry (\"deconfinement\") phase transition in\na pure glue theory at 300 MeV are two independent temperatures and their\ninterplay determines a structure of different regimes of hot QCD. Given a\nchiral spin symmetry of the color charge and of the chromoelectric interaction\nwe can conclude from observed symmetries of spatial and temporal correlators of\nN_F=2 QCD with domain wall Dirac operator at physical quark masses that above\nthe chiral symmetry restoration crossover around T_pc but below rougly 3T_pc\nthere should exist an intermediate regime (the stringy fluid) of hot QCD that\nis characterized by approximate chiral spin symmetry and where degrees of\nfreedom are chirally symmetric quarks bound into color singlet objects by the\nchromoelectric field. Above this intermediate regime the color charge and the\nchromoelectric field are Debye screened and one observes a transition to QGP\nwith magnetic confinement."
    },
    {
        "anchor": "Model study of the sign problem in a mean-field approximation: We study the sign problem of the fermion determinant at nonzero baryon\nchemical potential. For this purpose we apply a simple model derived from\nQuantum Chromodynamics, in the limit of large chemical potential and mass. For\nSU(2) color, there is no sign problem and the mean-field approximation is\nsimilar to data from the lattice. For SU(3) color the sign problem is\nunavoidable, even in a mean-field approximation. We apply a phase-reweighting\nmethod, combined with the mean-field approximation, to estimate thermodynamic\nquantities. We also investigate the mean-field free energy using a saddle-point\napproximation.",
        "positive": "Charmonia from Lattice QCD: Recent lattice QCD results on charmonium properties are reviewed. I comment\non molecules and hybrid states as well as on future studies of states near\nstrong decay thresholds."
    },
    {
        "anchor": "Abelian representation for nonabelian Wilson loops and the Non - Abelian\n  Stokes theorem on the lattice: We derive the Abelian - like expression for the lattice SU(N) Wilson loop in\narbitrary irreducible representation. The continuum Abelian representation of\nthe SU(N) Wilson loop (for the loop without selfintersections) that has been\nobtained by Diakonov and Petrov appears to be a continuum limit of this\nexpression. We also obtain the lattice variant of a non - Abelian Stokes\ntheorem and present the explicit expression for the matrix $\\cal H$ used in the\nDiakonov - Petrov approach.",
        "positive": "Composite Weak Bosons in a Confining Gauge Theory without Goldstone\n  Bosons: a Strong Coupling Expansion Analysis: We consider a confining Yang-Mills theory without Goldstone Bosons which\ncould describe the bosonic sector of the weak interactions. This model can be\ngauge invariantly regularized on a lattice. A strong coupling analysis of the\nlow lying bound state spectrum indicates that the vector isotriplet bound state\n(the right quantum number to represent the W-boson) could be the lightest state\nif the mass of the pseudoscalar isosinglet is raised sufficiently by the effect\nof the chiral anomaly (in analogy to the $\\eta'$ mechanism of QCD). This work\nis a preliminary study in support to an intensive lattice Monte Carlo analysis\nof the model."
    },
    {
        "anchor": "Doubly Heavy Baryons and Quark-Diquark Symmetry in Quenched and\n  Partially Quenched Chiral Perturbation Theory: We extend the chiral Lagrangian with heavy quark-diquark symmetry to quenched\nand partially quenched theories. These theories are used to derive formulae for\nthe chiral extrapolation of masses and hyperfine splittings of doubly heavy\nbaryons in lattice QCD simulations. A quark-diquark symmetry prediction for the\nhyperfine splittings of heavy mesons and doubly heavy baryons is rather\ninsensitive to chiral corrections in both quenched and partially quenched QCD.\nExtrapolation formulae for the doubly heavy baryon electromagnetic transition\nmoments are also determined for the partially quenched theory.",
        "positive": "First-order phase transitions in Yang-Mills theories and the density of\n  state method: When studied at finite temperature, Yang-Mills theories in $3+1$ dimensions\ndisplay the presence of confinement/deconfinement phase transitions, which are\nknown to be of first order -- the $SU(2)$ gauge theory being the exception.\nTheoretical as well as phenomenological considerations indicate that it is\nessential to establish a precise characterisation of these physical systems in\nproximity of such phase transitions. We present and test a new method to study\nthe critical region of parameter space in non-Abelian quantum field theories on\nthe lattice, based upon the Logarithmic Linear Relaxation (LLR) algorithm. We\napply this method to the $SU(3)$ Yang Mills lattice gauge theory, and perform\nextensive calculations with one fixed choice of lattice size. We identify the\ncritical temperature, and measure interesting physical quantities near the\ntransition. Among them, we determine the free energy of the model in the\ncritical region, exposing for the first time its multi-valued nature with a\nnumerical calculation from first principles, providing this novel evidence in\nsupport of a first order phase transition. This study sets the stage for future\nhigh precision measurements, by demonstrating the potential of the method."
    },
    {
        "anchor": "Large logarithmic rescaling of the scalar condensate: new lattice\n  evidences: Using two different methods, we have determined the rescaling of the scalar\ncondensate $Z\\equiv Z_\\phi$ near the critical line of a 4D Ising model. Our\nlattice data, in agreement with previous numerical indications, support the\nbehavior $Z_\\phi\\sim \\ln ({\\Lambda})$, $\\Lambda$ being the ultraviolet cutoff.\nThis result is predicted in an alternative description of symmetry breaking\nwhere there are no upper bounds on the Higgs boson mass from `triviality'.",
        "positive": "An numerical approach for finite volume three-body interaction: In present work, we study an numerical approach to one dimensional finite\nvolume three-body interaction, the method is demonstrated by considering a toy\nmodel of three spinless particles interacting with pair-wise $\\delta$-function\npotentials. The numerical results are compared with the exact solutions of\nthree spinless bosons interaction when strength of short-range interactions are\nset equal for all pairs."
    },
    {
        "anchor": "Universality and the approach to the continuum limit in lattice gauge\n  theory: The universality of the continuum limit and the applicability of renormalized\nperturbation theory are tested in the SU(2) lattice gauge theory by computing\ntwo different non-perturbatively defined running couplings over a large range\nof energies. The lattice data (which were generated on the powerful APE\ncomputers at Rome II and DESY) are extrapolated to the continuum limit by\nsimulating sequences of lattices with decreasing spacings. Our results confirm\nthe expected universality at all energies to a precision of a few percent. We\nfind, however, that perturbation theory must be used with care when matching\ndifferent renormalized couplings at high energies.",
        "positive": "Unstable Modes in Three-Dimensional SU(2) Gauge Theory: We investigate SU(2) gauge theory in a constant chromomagnetic field in three\ndimensions both in the continuum and on the lattice. Using a variational method\nto stabilize the unstable modes, we evaluate the vacuum energy density in the\none-loop approximation. We compare our theoretical results with the outcomes of\nthe numerical simulations."
    },
    {
        "anchor": "Finite-Volume Corrections to Electromagnetic Masses for\n  Larger-Than-Physical Electric Charges: The numerical value of the fine-structure constant generally leads to small\nisospin-breaking effects due to electromagnetism in QCD. This smallness\ncomplicates determining isospin breaking from lattice QCD computations that\ninclude electromagnetism. One solution to this problem consists of performing\ncomputations using larger-than-physical values of the electric charge, and\nsubsequently extrapolating (or interpolating) to the physical value of the\nfine-structure constant. Motivated by recent lattice QCD + QED computations of\nelectromagnetic masses employing this setup, we consider finite-volume effects\narising from the use of larger-than-physical electric charges. A modified\npower-counting scheme, which is based on treating the fine-structure constant\nas larger than its physical value, is explored. Results for perturbative QED\ncorrections, however, are surprising. Within the framework of non-relativistic\nQED, multi-loop diagrams exhibit a momentum factorization property that\nproduces exact cancellations. We determine that power-law finite-volume effects\nvanish at the leading two- and three-loop order, as well as the next-to-leading\ntwo-loop order. For larger-than-physical charges, we consequently expect no\nappreciable volume corrections beyond leading-order QED.",
        "positive": "Higher order tensor renormalization group for relativistic fermion\n  systems: We apply the higher order tensor renormalization group to two and three\ndimensional relativistic fermion systems on the lattice. In order to perform a\ncoarse-graining of tensor networks including Grassmann variables, we introduce\nGrassmann higher order tensor renormalization group. We test the validity of\nthe new algorithm by comparing its results with those of exact or previous\nmethods."
    },
    {
        "anchor": "The nature of the finite temperature QCD transition as a function of the\n  quark masses: The finite temperature QCD transition for physical quark masses is a\ncrossover. For smaller quark masses a first-order phase transition is expected.\nUsing Symanzik improved gauge and stout improved fermion action for 2+1 flavour\nstaggered QCD we give estimates/bounds for the phase line separating the\nfirst-order region from the crossover one. The calculations are carried out on\ntwo different lattice spacings. Our conclusion for the critical mass is $m_0\n\\lesssim 0.07 \\cdot m_{phys}$ for $N_T=4$ and $m_0 \\lesssim 0.12 \\cdot\nm_{phys}$ for $N_T=6$ lattices.",
        "positive": "Induced QCD II: Numerical results: We numerically explore an alternative discretization of continuum\n$\\text{SU}(N_c)$ Yang-Mills theory on a Euclidean spacetime lattice, originally\nintroduced by Budzcies and Zirnbauer for gauge group $\\text{U}(N_c)$. This\ndiscretization can be reformulated such that the self-interactions of the gauge\nfield are induced by a path integral over $N_b$ auxiliary bosonic fields, which\ncouple linearly to the gauge field. In the first paper of the series we have\nshown that the theory reproduces continuum $\\text{SU}(N_c)$ Yang-Mills theory\nin $d=2$ dimensions if $N_b$ is larger than $N_c-\\frac{3}{4}$ and conjectured,\nfollowing the argument of Budzcies and Zirnbauer, that this remains true for\n$d>2$. In the present paper, we test this conjecture by performing lattice\nsimulations of the simplest nontrivial case, i.e., gauge group $\\text{SU}(2)$\nin three dimensions. We show that observables computed in the induced theory,\nsuch as the static $q\\bar q$ potential and the deconfinement transition\ntemperature, agree with the same observables computed from the ordinary\nplaquette action up to lattice artifacts. We also find that the bound for $N_b$\ncan be relaxed to $N_c-\\frac{5}{4}$ as conjectured in our earlier paper.\nStudies of how the new discretization can be used to change the order of\nintegration in the path integral to arrive at dual formulations of QCD are left\nfor future work."
    },
    {
        "anchor": "Inverse problems, real-time dynamics and lattice simulations: The determination of real-time dynamics of strongly coupled quantum fields is\na central goal of modern nuclear and particle physics, which requires insight\ninto quantum field theory beyond the weak-coupling approximation. While lattice\nQCD has provided vital insights into the non-perturbative static properties of\nquarks and gluons it hides their real-time dynamics behind an ill-posed inverse\nproblem. In this proceeding I will discuss developments in tackling the inverse\nproblem on the lattice and touch upon progress in the direct simualtion of\nreal-time dynamics.",
        "positive": "Moments of structure functions for $N_f=2$ near the physical point: We report on our on-going study of the lower moments of iso-vector polarised\nand unpolarised structure functions, $g_A$ and $\\langle x\\rangle_{u-d}$,\nrespectively, and the iso-vector scalar and tensor charge, for $N_f=2$\nnon-perturbatively improved clover fermions. With pion masses which go down to\nabout 150 MeV, we investigate finite volume effects and excited state\ncontributions."
    },
    {
        "anchor": "Center vortex model for the infrared sector of Yang-Mills theory -\n  Quenched Dirac spectrum and chiral condensate: The Dirac operator describing the coupling of continuum quark fields to SU(2)\ncenter vortex world-surfaces composed of elementary squares on a hypercubic\nlattice is constructed. It is used to evaluate the quenched Dirac spectral\ndensity in the random vortex world-surface model, which previously has been\nshown to quantitatively reproduce both the confinement properties and the\ntopological susceptibility of SU(2) Yang-Mills theory. Under certain conditions\non the modeling of the vortex gauge field, a behavior of the quenched chiral\ncondensate as a function of temperature is obtained which is consistent with\nmeasurements in SU(2) lattice Yang-Mills theory.",
        "positive": "Nucleon spectroscopy using multi-particle operators: The role of 5-quark operators in extracting the nucleon excited state\nspectrum via correlation matrix techniques is explored. In particular, the\ncoupling of meson-baryon operators to nucleon resonance states and scattering\nstates is studied. Results are presented for 2+1 flavour dynamical ensembles in\nboth the positive and negative parity channels. Fitting a single-state ansatz\nto the eigenstate-projected correlators provides robust energies for the\nlow-lying spectrum that are essentially invariant across a variety of different\noperator bases. In particular, the resonant state energies obtained both with\nand without the use of meson-baryon operators agree, demonstrating that\nresonance energies can be reliably extracted solely using 3-quark operators."
    },
    {
        "anchor": "Pseudoscalar decay constants $f_K/f_\u03c0$, $f_D$ and $f_{D_s}$ with $N_f\n  = 2 + 1 + 1$ ETMC configurations: We present a lattice QCD calculation of the pseudoscalar decay constants\n$f_K$, $f_D$ and $f_{D_s}$ performed by the European Twisted Mass Collaboration\nwith $N_f = 2 + 1 + 1$ dynamical fermions. We simulated at three different\nvalues of the lattice spacing, the smallest being approximately $0.06fm$, and\nwith pion masses as small as $210$MeV. Our main results are:\n$f_{K^+}/f_{\\pi^+}=1.183(17)$, $f_{K^+}=154.4(2.1)$MeV,\n$f_{D_s}=242.1(8.3)$MeV, $f_D=201.9(8.0)$MeV, $f_{D_s}/f_D=1.199(25)$ and\n$(f_{D_s}/f_D) / (f_K/f_\\pi) = 1.005(15)$.",
        "positive": "The Phase Diagram of Crystalline Surfaces: We report the status of a high-statistics Monte Carlo simulation of\nnon-self-avoiding crystalline surfaces with extrinsic curvature on lattices of\nsize up to $128^2$ nodes. We impose free boundary conditions. The free energy\nis a gaussian spring tethering potential together with a normal-normal bending\nenergy. Particular emphasis is given to the behavior of the model in the cold\nphase where we measure the decay of the normal-normal correlation function."
    },
    {
        "anchor": "SUSY WT identity in a lattice formulation of 2D $\\mathcal{N}=(2,2)$ SYM: We address some issues relating to a supersymmetric (SUSY) Ward-Takahashi\n(WT) identity in Sugino's lattice formulation of two-dimensional (2D)\n$\\mathcal{N}=(2,2)$ $SU(k)$ supersymmetric Yang-Mills theory (SYM). A\nperturbative argument shows that the SUSY WT identity in the continuum theory\nis reproduced in the continuum limit without any operator\nrenormalization/mixing and tuning of lattice parameters. As application of the\nlattice SUSY WT identity, we show that a prescription for the hamiltonian\ndensity in this lattice formulation, proposed by Kanamori, Sugino and Suzuki,\nis justified also from a perspective of an operator algebra among\ncorrectly-normalized supercurrents. We explicitly confirm the SUSY WT identity\nin the continuum limit to the first nontrivial order in a semi-perturbative\nexpansion.",
        "positive": "Hermitizing the HAL QCD potential in the derivative expansion: A formalism is given to hermitize the HAL QCD potential, which needs to be\nnon-hermitian except the leading order (LO) local term in the derivative\nexpansion as the Nambu-Bethe-Salpeter (NBS) wave functions for different\nenergies are not orthogonal to each other. It is shown that the non-hermitian\npotential can be hermitized order by order to all orders in the derivative\nexpansion. In particular, the next-to-leading order (NLO) potential can be\nexactly hermitized without approximation. The formalism is then applied to a\nsimple case of $\\Xi \\Xi (^{1}S_{0}) $ scattering, for which the HAL QCD\ncalculation is available to the NLO. The NLO term gives relatively small\ncorrections to the scattering phase shift and the LO analysis seems justified\nin this case. We also observe that the local part of the hermitized NLO\npotential works better than that of the non-hermitian NLO potential. The\nhermitian version of the HAL QCD potential is desirable for comparing it with\nphenomenological interactions and also for using it as a two-body interaction\nin many body systems."
    },
    {
        "anchor": "Improved lattice QCD with quarks: the 2 dimensional case: QCD in two dimensions is investigated using the improved fermionic lattice\nHamiltonian proposed by Luo, Chen, Xu, and Jiang. We show that the improved\ntheory leads to a significant reduction of the finite lattice spacing errors.\nThe quark condensate and the mass of lightest quark and anti-quark bound state\nin the strong coupling phase (different from t'Hooft phase) are computed. We\nfind agreement between our results and the analytical ones in the continuum.",
        "positive": "Twisted Boundary Conditions in Lattice Simulations: By imposing twisted boundary conditions on quark fields it is possible to\naccess components of momenta other than integer multiples of 2pi/L on a lattice\nwith spatial volume L^3. We use Chiral Perturbation Theory to study\nfinite-volume effects with twisted boundary conditions for quantities without\nfinal-state interactions, such as meson masses, decay constants and\nsemileptonic form factors, and confirm that they remain exponentially small\nwith the volume. We show that this is also the case for \"partially twisted\"\nboundary conditions, in which (some of) the valence quarks satisfy twisted\nboundary conditions but the sea quarks satisfy periodic boundary conditions.\nThis observation implies that it is not necessary to generate new gluon\nconfigurations for every choice of the twist angle, making the method much more\npracticable. For K->pipi decays we show that the breaking of isospin symmetry\nby the twisted boundary conditions implies that the amplitudes cannot be\ndetermined in general (on this point we disagree with a recent claim)."
    },
    {
        "anchor": "Is the ground state of Yang-Mills theory Coulombic?: We study trial states modelling the heavy quark-antiquark ground state in\nSU(2) Yang-Mills theory. A state describing the flux tube between quarks as a\nthin string of glue is found to be a poor description of the continuum ground\nstate; the infinitesimal thickness of the string leads to UV artifacts which\nsuppress the overlap with the ground state. Contrastingly, a state which\nsurrounds the quarks with non-abelian Coulomb fields is found to have a good\noverlap with the ground state for all charge separations. In fact, the overlap\nincreases as the lattice regulator is removed. This opens up the possibility\nthat the Coulomb state is the true ground state in the continuum limit.",
        "positive": "Lattice Gauge Theories and Spin Models: The Wegner $Z_2$ gauge theory-$Z_2$ Ising spin model duality in $(2+1)$\ndimensions is revisited and derived through a series of canonical\ntransformations. The Kramers-Wannier duality is similarly obtained. The Wegner\n$Z_2$ gauge-spin duality is directly generalized to SU(N) lattice gauge theory\nin $(2+1)$ dimensions to obtain the SU(N) spin model in terms of the SU(N)\nmagnetic fields and their conjugate SU(N) electric scalar potentials. The exact\nand complete solutions of the $Z_2, U(1), SU(N)$ Gauss law constraints in terms\nof the corresponding spin or dual potential operators are given. The gauge-spin\nduality naturally leads to a new gauge invariant magnetic disorder operator for\nSU(N) lattice gauge theory which produces a magnetic vortex on the plaquette. A\nvariational ground state of the SU(2) spin model with nearest neighbor\ninteractions is constructed to analyze SU(2) gauge theory."
    },
    {
        "anchor": "Critical behaviour of the 1D q-state Potts model with long-range\n  interactions: The critical behaviour of the one-dimensional q-state Potts model with\nlong-range interactions decaying with distance r as $r^{-(1+\\sigma)}$ has been\nstudied in the wide range of parameters $0 < \\sigma \\le 1$ and $\\frac{1}{16}\n\\le q \\le 64$. A transfer matrix has been constructed for a truncated range of\ninteractions for integer and continuous q, and finite range scaling has been\napplied. Results for the phase diagram and the correlation length critical\nexponent are presented.",
        "positive": "Structure-dependent electromagnetic finite-volume effects through order\n  $1/L^3$: We consider electromagnetic finite-volume effects through order $1/L^3$ in\ndifferent formulations of QED, where $L$ is the periodicity of the spatial\nvolume. An inherent problem at this order is the appearance of\nstructure-dependent quantities related to form factors and the analytical\nstructure of the correlation functions. The non-local constraint of the widely\nused QED$_{\\textrm{L}}$ regularization gives rise to structure-dependent\neffects that are difficult to evaluate analytically and can act as a precision\nbottleneck in lattice calculations. For this reason, we consider general volume\nexpansions relevant for the mass spectrum as well as leptonic decay rates in\nQED$_{\\textrm{C}}$, QED$_{\\textrm{L}}$ and QED$_{\\textrm{L}}^{\\textrm{IR}}$,\nthe latter being a class of non-local formulations generalising\nQED$_{\\textrm{L}}$. One choice within this class is QED$_{\\textrm{r}}$, first\nintroduced at this conference, and we show that the effects of non-locality for\nthe $1/L^3$ term in the expansion can be removed. We observe that there are\nstill $1/L^3$ contributions unrelated to the (non-)locality of the studied QED\nformulations, but rather to collinear singularities in the physical amplitudes."
    },
    {
        "anchor": "Semi-leptonic form factors for $B_s \\to K \\ell \u03bd$ and $B_s \\to D_s\n  \\ell \u03bd$: Semi-leptonic $B_s \\to K \\ell \\nu$ and $B_s \\to D_s \\ell \\nu$ decays provide\nan alternative $b$-decay channel to determine the CKM matrix elements\n$|V_{ub}|$ and $|V_{cb}|$ or to obtain $R$-ratios to investigate lepton flavor\nuniversality violations. In addition, these decays may shed further light on\nthe discrepancies seen in the analysis of inclusive vs. exclusive decays. Using\nthe nonperturbative methods of lattice QCD, theoretical results are obtained\nwith good precision and full control over systematic uncertainties. This talk\nwill highlight ongoing efforts of the $B$-physics program by the RBC-UKQCD\ncollaboration.",
        "positive": "Spin dependent potentials from SU(2) gauge theory: We present results on spin dependent potentials from lattice simulations of\nSU(2) gauge theory. The Coulomb like short range part of the central potential\nis identified as a mixed vector-scalar exchange while the linear long range\npart is pure scalar."
    },
    {
        "anchor": "Topological charge density around static colour sources in lattice QCD\n  with dynamical quarks: We update our numerical investigation of topological structures around static\nquarks in pure gauge QCD by results of the first runs including dynamical\nquarks. Simulations were performed on an $8^3\\times4$ lattice, with $SU(3)$\nWilson action, with 3 flavours of quarks of equal mass, both in the confinement\nand deconfinement phase. In the confinement phase we observe indications for\nthe existence of a flux tube between a static quark and antiquark, flux-tube\nbreaking for large separations, and local correlation between the topological\ncharge density and chiral condensate. In the deconfinement phase almost all\nconfigurations turn out to be topologically trivial.",
        "positive": "D -> \u03c0l \u03bdand D -> K l \u03bdform factors with Nf=2+1+1 Twisted\n  fermions: We present a lattice QCD determination of the vector and scalar form factors\nof the semileptonic decays D->\\pi l \\nu and D -> K l \\nu which are relevant for\nthe extraction of the CKM matrix elements |Vcd| and |Vcs| from experimental\ndata. Our analysis is based on the gauge configurations produced by the\nEuropean Twisted Mass Collaboration with Nf = 2+1+1 dynamical fermions. We\nsimulated at three different values of the lattice spacing and with pion masses\nas small as 210 MeV. Our preliminary estimates for the vector form factor at\nzero 4-momentum transfer are f+(D -> \\pi)(0) = 0.610 (23) and f+(D -> K)(0) =\n0.747 (22), where the uncertainties are only statistical. By combining our\nresults with the experimental values of f+(D -> \\pi)(0) |Vcd| and f+(D -> K)(0)\n|Vcs| we obtain |Vcd| = 0.2336 (93) and |Vcs| = 0.975 (30), which together with\nthe PDG determination of |Vcb| are in agreement with the unitarity constraint\nof the Standard Model."
    },
    {
        "anchor": "A nonperturbative determination of c_A and the scaling of f_pi and\n  m^{MSbar}: We calculate the $O(a)$ improvement coefficient for the axial-vector current\nusing the nonperturbative method proposed by the LANL group. Results for the\ncoefficient in the range $\\beta=5.93$ to 6.2 are presented. We find $c_A$ is\nclose to the 1-loop tadpole-improved perturbative value. In addition, scaling\nof the pseudoscalar decay constant and renormalised quark mass is improved\ncompared to that obtained using the (larger) $c_A$ values obtained by the ALPHA\ncollaboration.",
        "positive": "Anisotropic Gauge Theories: A Numerical Study of the Fu-Nielsen Model: We study numerically 4+1 dimensional pure gauge theory."
    },
    {
        "anchor": "Low-mode averaging for baryon correlation functions: The low-mode averaging technique is a powerful tool for reducing large\nfluctuations in correlation functions due to low-mode eigenvalues of the Dirac\noperator. In this work we propose a generalization to baryons and test our\nmethod on two-point correlation functions of left-handed nucleons, computed\nwith quenched Neuberger fermions on a lattice with extension L=1.5 fm. We show\nthat the statistical fluctuations can be reduced and the baryon signal\nsignificantly improved.",
        "positive": "Baryon interactions from lattice QCD with physical masses -- $S=-2$\n  sector --: The strangeness $S=-2$ baryon-baryon interaction is investigated directly\nfrom the fundamental theory of the strong interaction, QCD. The HAL QCD method\nenables us to extract baryon interactions from the Nambu-Bethe-Salpeter wave\nfunctions without using any experimental information. We present our latest\nresult on the $S = -2$ baryon interactions and discuss the H-dibaryon state\nusing potentials which are calculated by using the (almost) physical point\ngauge configurations with large lattice volume of$(8.1{\\rm{fm}})^4$ generated\non the K-computer."
    },
    {
        "anchor": "Overlap valence quarks on a twisted mass sea: a case study for mixed\n  action Lattice QCD: We discuss a Lattice QCD mixed action investigation employing Wilson\nmaximally twisted mass sea and overlap valence fermions. Using four values of\nthe lattice spacing, we demonstrate that the overlap Dirac operator assumes a\npoint-like locality in the continuum limit. We also show that by adopting\nsuitable matching conditions for the sea and valence theories a consistent\ncontinuum limit for the pion decay constant and light baryon masses can be\nobtained. Finally, we confront results for sea-valence mixed meson masses and\nthe valence scalar correlator with corresponding expressions of chiral\nperturbation theory. This allows us to extract low energy constants of mixed\naction chiral perturbation which characterize the strength of unitarity\nviolations in our mixed action setup.",
        "positive": "Finite-Size Scaling in the $O(N)$ $\u03c6^4_4$ Model: Perturbation theory and renormalization group methods are used to derive a\nfinite-size scaling theory for the partition function zeroes and thermodynamic\nfunctions in the $O(n)$ $\\phi^4$ model in four dimensions. The leading\npower--law scaling behaviour is the same as that of the mean field theory.\nThere exist, however, multiplicative logarithmic corrections which are linked\nto the triviality of the theory."
    },
    {
        "anchor": "Type of dual superconductivity for the $SU(2)$ Yang--Mills theory: We investigate the type of dual superconductivity responsible for quark\nconfinement. For this purpose, we solve the field equations of the $U(1)$\ngauge-scalar model to obtain the static vortex solution in the whole range\nwithout restricting to the long-distance region. Then we use the resulting\nmagnetic field of the vortex to fit the gauge-invariant chromoelectric field\nconnecting a pair of quark and antiquark which was measured by numerical\nsimulations for $SU(2)$ Yang--Mills theory on a lattice. This result improves\nthe accuracy of the fitted value for the Ginzburg--Landau parameter to\nreconfirm the type I dual superconductivity for quark confinement which was\nclaimed by preceding works based on a fitting using the Clem ansatz. Moreover,\nwe calculate the Maxwell stress tensor to obtain the distribution of the force\naround the flux tube. This result suggests that the attractive force acts among\nchromoelectric flux tubes, in agreement with the type I dual superconductivity.",
        "positive": "Charmonium-like resonances in coupled $D \\bar D$-$D_s \\bar D_s$\n  scattering: Charmonium-like resonances and bound states with isospin zero and\n$J^{PC}=0^{++},~1^{--},~2^{++},~3^{--}$ are extracted on the lattice. Coupled\n$D\\bar D$ and $D_s\\bar D_s$ scattering suggests three charmonium-like states\nwith $J^{PC}=0^{++}$ in addition to $\\chi_{c0}(1P)$: a so far unobserved $D\\bar\nD$ bound state just below threshold, a conventional resonance likely related to\n$\\chi_{c0}(3860)/\\chi_{c0}(2P)$ and a narrow resonance just below the $D_s\\bar\nD_s$ threshold with a large coupling to $D_s\\bar D_s$ likely related to\n$X(3915)/\\chi_{c0}(3930)$. One-channel $D\\bar D$ scattering renders resonances\nand bound states with $J^{PC}= 1^{--},~2^{++},~3^{--}$ related to the observed\nconventional charmonia. Lattice QCD ensembles from the CLS consortium with\n$m_{\\pi}\\simeq 280$ MeV are utilized."
    },
    {
        "anchor": "Nucleon form factors from quenched lattice QCD with domain wall fermions: We present a quenched lattice calculation of the weak nucleon form factors:\nvector (F_V(q^2)), induced tensor (F_T(q^2)), axial-vector (F_A(q^2)) and\ninduced pseudo-scalar (F_P(q^2)) form factors. Our simulations are performed on\nthree different lattice sizes L^3 x T=24^3 x 32, 16^3 x 32 and 12^3 x 32 with a\nlattice cutoff of 1/a = 1.3 GeV and light quark masses down to about 1/4 the\nstrange quark mass (m_{pi} = 390 MeV) using a combination of the DBW2 gauge\naction and domain wall fermions. The physical volume of our largest lattice is\nabout (3.6 fm)^3, where the finite volume effects on form factors become\nnegligible and the lower momentum transfers (q^2 = 0.1 GeV^2) are accessible.\nThe q^2-dependences of form factors in the low q^2 region are examined. It is\nfound that the vector, induced tensor, axial-vector form factors are well\ndescribed by the dipole form, while the induced pseudo-scalar form factor is\nconsistent with pion-pole dominance. We obtain the ratio of axial to vector\ncoupling g_A/g_V=F_A(0)/F_V(0)=1.219(38) and the pseudo-scalar coupling\ng_P=m_{mu}F_P(0.88m_{mu}^2)=8.15(54), where the errors are statistical erros\nonly. These values agree with experimental values from neutron beta decay and\nmuon capture on the proton. However, the root mean squared radii of the vector,\ninduced tensor and axial-vector underestimate the known experimental values by\nabout 20%. We also calculate the pseudo-scalar nucleon matrix element in order\nto verify the axial Ward-Takahashi identity in terms of the nucleon matrix\nelements, which may be called as the generalized Goldberger-Treiman relation.",
        "positive": "Masses of the conjectured H-dibaryon at different temperatures: We present a lattice QCD determination of masses of the conjectured\nH-dibaryon $m_H$ at nine different temperatures $T/T_c =0.24, 0.63, 0.76, 0.84,\n0.95, 1.09, 1.27, 1.52, 1.90$. In the meantime, the masses of baryons $N$,\n$\\Sigma$, $\\Xi$ and $\\Lambda$ at different temperatures are also computed. The\nsimulation is performed on anisotropic lattice with $N_f=2+1$ flavours of\nclover fermion at quark mass which corresponds to $m_\\pi=384(4) {\\rm MeV} $.\nThe thermal ensembles were provided by the FASTSUM collaboration and the zero\ntemperature ensembles by the Hadspec collaboration. We also calculate the\nspectral density of the correlation function of those particles. The spectral\ndensity distributions show rich peak structure at the lowest temperature, while\nat intermediate temperatures, the mass values of those particles obtained by\nfitting procedure reflect a two-peak structure. While the spectral density for\noctet baryons becomes smooth at $T/T_c = 1.27, 1.52, 1.90$, the spectral\ndensity for H-dibaryon becoms smooth at $T/T_c = 1.90$. The negative mass\ndifference $\\Delta m = m_H - 2\\,m_{\\Lambda} $ of H-dibaryon and $\\Lambda$ pair\nat $T/T_c =0.24 $ is estimated to be $\\Delta m = -92(12) {\\rm MeV}$ which\nsuggests there exists a bound H-dibaryon state."
    },
    {
        "anchor": "Renormalization of minimally doubled fermions: We investigate the renormalization properties of minimally doubled fermions,\nat one loop in perturbation theory. Our study is based on the two particular\nrealizations of Borici-Creutz and Karsten-Wilczek. A common feature of both\nformulations is the breaking of hyper-cubic symmetry, which requires that the\nlattice actions are supplemented by suitable counterterms. We show that three\ncounterterms are required in each case and determine their coefficients to one\nloop in perturbation theory. For both actions we compute the vacuum\npolarization of the gluon. It is shown that no power divergences appear and\nthat all contributions which arise from the breaking of Lorentz symmetry are\ncancelled by the counterterms. We also derive the conserved vector and\naxial-vector currents for Karsten-Wilczek fermions. Like in the case of the\npreviously studied Borici-Creutz action, one obtains simple expressions,\ninvolving only nearest-neighbour sites. We suggest methods how to fix the\ncoefficients of the counterterms non-perturbatively and discuss the\nimplications of our findings for practical simulations.",
        "positive": "On the spectrum of the QCD Dirac operator: In this lecture we argue that the fluctuations of Dirac eigenvalues on the\nfinest scale, i.e. on the scale of the average level spacing do not depend on\nthe underlying dynamics and can be obtained from a chiral random matrix theory\nwith the same low energy effective theory. We present three pieces of evidence\nsupporting that such microscopic correlations of lattice QCD Dirac spectra are\ngiven by chiral random matrix theory. First, we find that the spectral\ncorrelations of eigenvalues in the bulk of the spectrum obey the\nDyson-Mehta-Wigner statistics. Second, we show that the valence quark mass\ndependence for sufficiently small quark masses, as calculated by the Columbia\ngroup, can be obtained from the microscopic spectral density of chiral random\nmatrix theory. Third, in the framework of chiral random matrix models, we\npresent results showing that the microscopic spectral density is strongly\nuniversal, i.e. is insensitive to the details of the probability distribution."
    },
    {
        "anchor": "The moment $\\langle x\\rangle_{u-d}$ of the nucleon from $N_f=2$ lattice\n  QCD down to nearly physical quark masses: We present an update of our analysis [1] which includes additional ensembles\nat different quark masses, lattice spacings and volumes, all with high\nstatistics. We use $N_f=2$ mass-degenerate quark flavours, employing the\nnon-perturbatively improved clover action. The lattice matrix elements are\nconverted to the $\\overline{\\rm MS}$ scheme via renormalization factors\ndetermined non-perturbatively in the RI$^\\prime$-MOM scheme. We have\nsystematically investigated excited state contributions, in particular, at the\nsmallest, near physical, pion mass. While our results~(with much increased\nprecision) are consistent with Ref.~[1], comparing with previous determinations\nwe find that excited state contributions can be significant if the quark\nsmearing is not suitably optimized, in agreement with other recent studies. The\ndifference with respect to the value for $\\langle x\\rangle_{u-d}$ extracted\nfrom experimental data is reduced but not resolved. Using lattice sizes in the\nrange $L m_\\pi\\sim 3.4-6.7$, no significant finite volume effects were\nobserved. Performing a controlled continuum limit that may remove the\ndiscrepancy will require simulations at lattice spacings $a< 0.06$ fm.",
        "positive": "First study of twist-3 PDFs for the proton from lattice QCD: In these proceedings, we summarize the main results from the first-ever\ncalculations of the chiral-even and chiral-odd twist-3 parton distributions,\n$g_T(x)$ and $h_L(x)$, of the proton from lattice QCD. We use an $N_f=2+1+1$\nensemble of maximally twisted mass fermions with a clover improvement. The\nlattice has a spatial extent of 3~fm, the lattice spacing is 0.093~fm, and the\npion mass is $260$~MeV. The matrix elements are obtained with a source-sink\ntime separation of 1.12~fm to control contamination from excited states. The\ncalculation is based on the quasi-PDF approach and employs three values for the\nproton momentum: 0.83~GeV, 1.25~GeV, and 1.67~GeV. The lattice data are\nrenormalized non-perturbatively using the RI$'$ scheme, and the final results\nare presented in the $\\overline{\\rm MS}$ scheme at the scale of 2~GeV.\nFurthermore, we compute in the same setup the helicity, $g_1(x)$, and\ntransversity, $h_1(x)$, distributions, which are used to compare $g_T(x)$ and\n$h_L(x)$ to their Wandzura-Wilczek approximations. For $h_L(x)$, we combine\nresults for the isovector and isoscalar flavor combinations to disentangle the\nindividual up- and down-quark contributions."
    },
    {
        "anchor": "The gluino-glue particle and finite size effects in supersymmetric\n  Yang-Mills theory: The spectrum of particles in supersymmetric Yang-Mills theory is expected to\ncontain a spin 1/2 bound state of gluons and gluinos, the gluino-glue particle.\nWe study the mass of this particle in softly broken supersymmetric Yang-Mills\ntheory on a lattice by means of numerical simulations. The main focus is the\nestimation of finite size effects. We extrapolate the mass first to the\ninfinite volume and then to the limit of a vanishing gluino mass. The results\nindicate that finite size effects are tolerable on lattices of moderate size,\nand that remaining deviations from supersymmetry are probably due to finite\nlattice spacing effects.",
        "positive": "B meson decay constant from quenched Lattice QCD: A lattice QCD calculation of the B meson decay constant is presented. In\norder to investigate the scaling violation associated with the heavy quark,\nparallel simulations are carried out employing both Wilson and the\nO(a)-improved clover actions for the heavy quark. The discretization errors due\nto the large $b$ quark mass are estimated in a systematic way with the aid of\nthe non-relativistic interpretation approach of El-Khadra, Kronfeld and\nMackenzie. As our best value from the quenched simulations at $\\beta$=5.9, 6.1\nand 6.3 we obtain $f_B$=163$\\pm$16 MeV and $f_{B_s}$=175$\\pm$18 MeV in the\ncontinuum limit where the error includes both statistical and systematic\nuncertainties."
    },
    {
        "anchor": "Update on a short-distance D^0-meson mixing calculation with $N_f=2+1$\n  flavors: We present an update on our calculation of the short-distance $D^0$-meson\nmixing hadronic matrix elements. The analysis is performed on the MILC\ncollaboration's $N_f=2+1$ asqtad configurations. We use asqtad light valence\nquarks and the Sheikoleslami-Wohlert action with the Fermilab interpretation\nfor the valence charm quark. SU(3), partially quenched, rooted, staggered\nheavy-meson chiral perturbation theory is used to extrapolate to the\nchiral-continuum limit. Systematic errors arising from the chiral-continuum\nextrapolation, heavy-quark discretization, and quark-mass uncertainties are\nfolded into the statistical errors from the chiral-continuum fits with methods\nof Bayesian inference. A preliminary error budget for all five operators is\npresented.",
        "positive": "Theoretical Bounds on New Four-Fermion Interactions and TeV Scale\n  Physics: The standard model weak interactions can be described by four-fermion V-A\noperators at low energies. New physics at the TeV scale can, however, generate\nthe other Lorentz structures. In this talk, we review the constraints on such\ninteractions from nuclear and hadronic decays, as well as from collider\nsearches. Currently the most stringent bounds come from the analysis of the 0+\nto 0+ nuclear and the pi to e nu gamma radiative pion decays. In the near\nfuture, the ultracold neutron beta decay experiments and the direct LHC\nmeasurements will compete in setting the most stringent bounds, provided,\nhowever, that the neutron-to-proton non-perturbative transition matrix elements\ncan be calculated to a level of 10-20% accuracy."
    },
    {
        "anchor": "Calculation of Nucleon Electromagnetic Form Factors: The fomalism is developed to express nucleon matrix elements of the\nelectromagnetic current in terms of form factors consistent with the\ntranslational, rotational, and parity symmetries of a cubic lattice. We\ncalculate the number of these form factors and show how appropriate linear\ncombinations approach the continuum limit.",
        "positive": "Critical Behaviour in the Single Flavor Thirring Model in 2+1d: Results of a lattice field theory simulation of the single-flavor Thirring\nmodel in 2+1 spacetime dimensions are presented. The lattice model is\nformulated using domain wall fermions as a means to recover the correct U(2)\nsymmetries of the continuum model in the limit where wall separation\n$L_s\\to\\infty$. Simulations on $12^3, 16^3\\times L_s$, varying self-interaction\nstrength $g^2$ and bare mass $m$ are performed with $L_s = 8, \\ldots 48$, and\nthe results for the bilinear condensate $\\langle\\bar\\psi\\psi\\rangle$ fitted to\na model equation of state assuming a U(2)$\\to$U(1)$\\otimes$U(1)\nsymmetry-breaking phase transition at a critical $g_c^2$. First estimates for\n$g^{-2}a$ and critical exponents are presented, showing small but significant\ndepartures from mean-field values. The results confirm that a symmetry-breaking\ntransition does exist and therefore the critical number of flavors for the\nThirring model $N_c > 1$. Results for both condensate and associated\nsusceptibility are also obtained in the broken phase on $16^3\\times48$,\nsuggesting that here the $L_s\\to\\infty$ extrapolation is not yet under control.\nWe also present results obtained with the associated 2+1$d$ truncated overlap\noperator DOL demonstrating exponential localisation, a necessary condition for\nthe recovery of U(2) global symmetry, but that recovery of the Ginsparg-Wilson\ncondition as $L_s\\to\\infty$ is extremely slow in the broken phase."
    },
    {
        "anchor": "$B_K$ in unquenched QCD using improved staggered fermions: We present preliminary results for $B_K$ calculated using improved staggered\nfermions with a mixed action (HYP-smeared staggered valence quarks and AsqTad\nstaggered sea quarks). We investigate the effect of non-degenerate quarks on\n$B_K$ and attempt to estimate the ${\\cal O}(a^2)$ effect due to non-Goldstone\npions in loops. We fit the data to continuum partially quenched chiral\nperturbation theory. We find that the quality of fit for $B_K$ improves if we\ninclude non-degenerate quark mass combinations. We also observe, however, that\nthe fitting curve deviates from the data points in the light quark mass region.\nThis may indicate the need to include taste-breaking in pion loops.",
        "positive": "Phase structure of SU(3) gauge theory with two flavors of\n  symmetric-representation fermions: We have performed numerical simulations of SU(3) gauge theory coupled to Nf=2\nflavors of symmetric representation fermions. The fermions are discretized with\nthe tadpole-improved clover action. Our simulations are done on lattices of\nlength L=6, 8, and 12. In all simulation volumes we observe a crossover from a\nstrongly coupled confined phase to a weak coupling deconfined phase.\nDegeneracies in screening masses, plus the behavior of the pseudoscalar decay\nconstant, indicate that the deconfined phase is also a phase in which chiral\nsymmetry is restored. The movement of the confinement transition as the volume\nis changed is consistent with avoidance of the basin of attraction of an\ninfrared fixed point of the massless theory."
    },
    {
        "anchor": "Inclusion of isospin breaking effects in lattice simulations: Isospin symmetry is explicitly broken in the Standard Model by the mass and\nelectric charge of the up and down quarks. These effects represent a\nperturbation of hadronic amplitudes at the percent level. Although these\ncontributions are small, they play a crucial role in hadronic and nuclear\nphysics. Moreover, as lattice computations are becoming increasingly precise,\nit is becoming more and more important to include these effects in numerical\nsimulations. We summarize here how to properly define QCD and QED on a finite\nand discrete space-time so that isospin corrections to hadronic observables can\nbe computed ab-initio and we review the main results on the isospin corrections\nto the hadron spectrum. We mainly focus on the recent work going beyond the\nelectro-quenched approximation.",
        "positive": "Lattice Models of Quantum Gravity: Standard Regge Calculus provides an interesting method to explore quantum\ngravity in a non-perturbative fashion but turns out to be a CPU-time demanding\nenterprise. One therefore seeks for suitable approximations which retain most\nof its universal features. The $Z_2$-Regge model could be such a desired\nsimplification. Here the quadratic edge lengths $q$ of the simplicial complexes\nare restricted to only two possible values $q=1+\\epsilon\\sigma$, with\n$\\sigma=\\pm 1$, in close analogy to the ancestor of all lattice theories, the\nIsing model. To test whether this simpler model still contains the essential\nqualities of the standard Regge Calculus, we study both models in two\ndimensions and determine several observables on the same lattice size. In order\nto compare expectation values, e.g. of the average curvature or the Liouville\nfield susceptibility, we employ in both models the same functional integration\nmeasure. The phase structure is under current investigation using mean field\ntheory and numerical simulation."
    },
    {
        "anchor": "Multicanonical Hybrid Monte Carlo: Boosting Simulations of Compact QED: We demonstrate that substantial progress can be achieved in the study of the\nphase structure of 4-dimensional compact QED by a joint use of hybrid Monte\nCarlo and multicanonical algorithms, through an efficient parallel\nimplementation. This is borne out by the observation of considerable speedup of\ntunnelling between the metastable states, close to the phase transition, on the\nWilson line. We estimate that the creation of adequate samples (with order 100\nflip-flops) becomes a matter of half a year's runtime at 2 Gflops sustained\nperformance for lattices of size up to 24^4.",
        "positive": "Hopping Parameter Expansion for Heavy-Light Systems: We present a technique which permits the calculation of two-point functions\nof operators containing one heavy quark and an arbitrary number of light quarks\nas analytic functions of the heavy-quark mass. It is based on the standard\nJacobi linear solver used for the calculation of quark propagators. Results for\nthe heavy-light pseudoscalar and vector meson masses are obtained on 16^3x48\nlattices at beta = 6.2 using the Wilson fermion action, and agree with\npublished data. The incorporation of smeared operators and $O(a)$-improved\nactions presents no problems."
    },
    {
        "anchor": "Coherent center domains from local Polyakov loops: We analyze properties of local Polyakov loops using quenched as well as\ndynamical SU(3) gauge configurations for a wide range of temperatures. It is\ndemonstrated that for both, the confined and the deconfined regime, the local\nPolyakov loop prefers phase values near the center elements 1, exp(i 2 pi/3),\nexp(-i 2 pi/3). We divide the lattice sites into three sectors according to\nthese phases and show that the sectors give rise to the formation of clusters.\nFor a suitable definition of these clusters we find that in the quenched case\ndeconfinement manifests itself as the onset of percolation of the clusters. A\npossible continuum limit of the center clusters is discussed.",
        "positive": "Complete supersymmetry on the lattice and a No-Go theorem: A simulation\n  with intact supersymmetries on the lattice: In this work a lattice formulation of a supersymmetric theory is proposed and\ntested that preserves the complete supersymmetry on the lattice. The results of\na one-dimensional nonperturbative simulation show the realization of the full\nsupersymmetry and the correct continuum limit of the theory. It is proven that\nthe violation of supersymmetry due to the absence of the Leibniz rule on the\nlattice can be amended only with a nonlocal derivative and nonlocal interaction\nterm. The fermion doubling problem is also discussed, which leads to another\nimportant source of supersymmetry breaking on the lattice. This problem is also\nsolved with a nonlocal realization."
    },
    {
        "anchor": "Structure of hybrid static potential flux tubes in lattice Yang-Mills\n  theory: We report about an ongoing lattice field theory project concerned with the\ninvestigation of heavy hybrid mesons. In particular we discuss our computation\nof the structure of hybrid static potential flux tubes in SU(2) lattice\nYang-Mills theory, which is based on the squares of the chromoelectric and\nchromomagnetic field strength components. Our flux tube results for hybrid\nstatic potential quantum numbers $\\Sigma_g^-$, $\\Sigma_u^+$, $\\Sigma_u^-$,\n$\\Pi_g$, $\\Pi_u$, $\\Delta_g$, $\\Delta_u$ are significantly different compared\nto the flux tube of the ordinary static potential.",
        "positive": "Numerical Evidence for Fractional Topological Objects in SU(3) Gauge\n  Theory: The continued development of models which propose the existence of fractional\ntopological objects in the Yang-Mills vacuum has called for a quantitative\nmethod to study the topological structure of SU($N$) gauge theory. We present\nan original numerical algorithm which can identify distinct topological objects\nin the nontrivial ground-state fields and approximate the net charge contained\nwithin them. This analysis is performed for SU(3) colour at a range of\ntemperatures crossing the deconfinement phase transition, allowing for an\nassessment of how the topological structure evolves with temperature. We find a\npromising consistency with the instanton-dyon model for the structure of the\nQCD vacuum at finite temperature. Several other quantities, such as object\ndensity and radial size, are also analysed to elicit a further understanding of\nthe fundamental structure of ground-state gluon fields."
    },
    {
        "anchor": "Exploring the chiral singularities of two color lattice QCD at strong\n  coupling: We use a modified directed path algorithm to study the finite temperature\nchiral singularities of two color lattice QCD with staggered fermions at strong\ncoupling. Our lattice calculations are done at a fixed finite temperature in\nthe broken phase with a variety of different quark masses. We find that to the\nlowest order, the behavior of our observables, namely the condensates and the\ndecay constants are all consistent with the predictions of the low energy\neffective theory of our model. We further notice that in order to see\nconsistency, the quark masses used in our lattice calculations need to be quite\nsmall than typically used.",
        "positive": "The exact decomposition of gauge variables in lattice Yang-Mills theory: In this paper, we consider lattice versions of the decomposition of the Yang-\nMills field a la Cho-Faddeev-Niemi, which was extended by Kondo, Shinohara and\nMurakami in the continuum formulation. For the SU(N) gauge group, we propose a\nset of defining equations for specifying the decomposition of the gauge link\nvariable and solve them exactly without using the ansatz adopted in the\nprevious studies for SU(2) and SU(3). As a result, we obtain the general form\nof the decomposition for SU(N) gauge link variables and confirm the previous\nresults obtained for SU(2) and SU(3)."
    },
    {
        "anchor": "Deconfinement, Chiral Symmetry Breaking and Chiral Polarization: We examine the feasibility of the proposition that there is a temperature\nrange T$_c$ < T < T$_{ch}$ in N$_f$=0 QCD, where real Polyakov line\n(deconfined) vacuum exhibits valence spontaneous chiral symetry breaking and\ndynamical chiral polarization of Dirac eigenmodes. Detailed finite-volume\nanalysis convincingly demonstrates the existence of such phase at fixed cutoff\n(a=0.085 fm). Moreover, it is found that this behavior also takes place closer\nto the continuum limit (a=0.060 fm) without qualitative change in its\nproperties.",
        "positive": "Cutoff effects in meson spectral functions: We study the lattice spacing dependence of meson spectral functions\ncalculated in quenched QCD with domain wall fermions as well as clover Wilson\nfermions in quenched and partially-quenched QCD. We conclude that for lattice\nspacing $a \\le 3$ GeV all excited states appearing in the spectral functions\nare lattice artifacts."
    },
    {
        "anchor": "The monopole mass in the three-dimensional Georgi-Glashow model: We study the three-dimensional Georgi-Glashow model to demonstrate how\nmagnetic monopoles can be studied fully non-perturbatively in lattice Monte\nCarlo simulations, without any assumptions about the smoothness of the field\nconfigurations. We examine the apparent contradiction between the conjectured\nanalytic connection of the `broken' and `symmetric' phases, and the\ninterpretation of the mass (i.e., the free energy) of the fully quantised 't\nHooft-Polyakov monopole as an order parameter to distinguish the phases. We use\nMonte Carlo simulations to measure the monopole free energy and its first\nderivative with respect to the scalar mass. On small volumes we compare this to\nsemi-classical predictions for the monopole. On large volumes we show that the\nfree energy is screened to zero, signalling the formation of a confining\nmonopole condensate. This screening does not allow the monopole mass to be\ninterpreted as an order parameter, resolving the paradox.",
        "positive": "Light hadronic physics using domain wall fermions in quenched lattice\n  QCD: In the past year domain wall fermion simulations have moved from exploratory\nstages to the point where systematic effects can be studied with different\ngauge couplings, volumes, and lengths in the fifth dimension. Results are\npresented here for the chiral condensate, the light hadron spectrum, and the\nstrange quark mass. We focus especially on the pseudoscalar meson mass and show\nthat, in small volume, the correlators used to compute it can be contaminated\nto different degrees by topological zero modes. In large volume a nonlinear\nextrapolation to the chiral limit, e.g. as expected from quenched chiral\nperturbation theory, is needed in order to have a consistent picture of low\nenergy chiral symmetry breaking effects."
    },
    {
        "anchor": "Charge Symmetry Breaking in Parton Distribution Functions from Lattice\n  QCD: By determining the quark momentum fractions of the octet baryons from N_f=2+1\nlattice simulations, we are able to predict the degree of charge symmetry\nviolation in the parton distribution functions of the nucleon. This is of\nimportance, not only as a probe of our understanding of the non-perturbative\nstructure of the proton but also because such a violation constrains the\naccuracy of global fits to parton distribution functions and hence the accuracy\nwith which, for example, cross sections at the LHC can be predicted. A\nviolation of charge symmetry may also be critical in cases where symmetries are\nused to guide the search for physics beyond the Standard Model.",
        "positive": "Lattice QCD calculation of form factors describing the rare decays $B\n  \\to K^* \\ell^+ \\ell^-$ and $B_s \\to \u03c6\\ell^+ \\ell^-$: The rare decays $B^0 \\to K^{*0} \\mu^+ \\mu^-$ and $B_s \\to \\phi \\mu^+ \\mu^-$\nare now being observed with enough precision to test Standard Model\npredictions. A full understanding of these decays requires accurate\ndeterminations of the corresponding hadronic form factors. Here we present\nresults of lattice QCD calculations of the $B \\to K^*$ and $B_s \\to \\phi$ form\nfactors; we also determine the form factors relevant for the tree-level decays\n$B_s \\to K^* \\ell \\nu$. We use full-QCD configurations including 2+1 flavors of\nsea quarks using an improved staggered action, and we employ lattice\nnon-relativistic QCD to describe the bottom quark."
    },
    {
        "anchor": "The Dirac operator spectrum: a perturbative approach: By computing the Dirac operator spectrum by means of Numerical Stochastic\nPerturbation Theory, we aim at throwing some light on the widely accepted\npicture for the mechanism which is behind the Bank-Casher relation. The latter\nrelates the chiral condensate to an accumulation of eigenvalues in the low end\nof the spectrum. This can be in turn ascribed to the usual mechanism of\nrepulsion among eigenvalues which is typical of quantum interactions. First\nresults appear to confirm that NSPT can indeed enable us to inspect a huge\nreshuffling of eigenvalues due to quantum repulsion.",
        "positive": "Towards the continuum limit in transport coefficient computations: The analytic continuation needed for the extraction of transport coefficients\nnecessitates in principle a continuous function of the Euclidean time variable.\nWe report on progress towards achieving the continuum limit for 2-point\ncorrelator measurements in thermal SU(3) gauge theory, with specific attention\npaid to scale setting. In particular, we improve upon the determination of the\ncritical lattice coupling and the critical temperature of pure SU(3) gauge\ntheory, estimating r0*Tc ~ 0.7470(7) after a continuum extrapolation. As an\napplication the determination of the heavy quark momentum diffusion coefficient\nfrom a correlator of colour-electric fields attached to a Polyakov loop is\ndiscussed."
    },
    {
        "anchor": "Quenched Charmed Meson Spectra using Tadpole Improved Quark Action on\n  Anisotropic Lattices: Charmed meson charmonium spectra are studied with improved quark actions on\nanisotropic lattices. We measured the pseudo-scalar and vector meson dispersion\nrelations for 4 lowest lattice momentum modes with quark mass values ranging\nfrom the strange quark to charm quark with 3 different values of gauge coupling\n$\\beta$ and 4 different values of bare speed of light $\\nu$. With the bare\nspeed of light parameter $\\nu$ tuned in a mass-dependent way, we study the mass\nspectra of $D$, $D_s$, $\\eta_c$,\n  $D^{\\ast}$, $D_s^{\\ast}$ and $J/\\psi$ mesons.\n  The results extrapolated to the continuum limit are compared with the\nexperiment and qualitative agreement is found.",
        "positive": "An Analytic Study of the Phase Structure of Lattice QCD with Wilson\n  Fermions at Infinitely Strong Coupling: The phase structure of lattice QCD with two flavors and Wilson fermions is\nstudied analytically. At $\\beta=0$ we obtain rigorous lower and upper bounds\nfor the critical hopping parameter $k_c(0)$ from a convergent hopping parameter\nexpansion to infinite order. The result supports the value $k_c(0)=\\frac{1}{4}$\nobserved in Monte Carlo simulations."
    },
    {
        "anchor": "Measuring the Decorrelation Times of Fourier Modes in Simulations: We describe a method to study the rate at which modes decorrelate in\nnumerical simulations. We study the XY model updated with the Metropolis and\nWolff dynamics respectively and compute the rate at which each eigenvector of\nthe dynamics decorrelates. Our method allows us to identify the decorrelation\ntime for each mode separately. We find that the autocorrelation function of the\nvarious modes is markedly different for the `local' Metropolis compared to the\n`non-local' Wolff dynamics. Equipped with this new insight, it may be possible\nto devise highly efficient algorithms.",
        "positive": "Conserved Charge Fluctuations from Lattice QCD and the Beam Energy Scan: We discuss the next-to-leading order Taylor expansion of ratios of cumulants\nof net-baryon number fluctuations. We focus on the relation between the\nskewness ratio, $S_B\\sigma_B = \\chi_3^B/\\chi_1^B$, and the kurtosis ratio,\n$\\kappa_B\\sigma_B^2 =\\chi_4^B/\\chi_2^B$. We show that differences in these two\ncumulant ratios are small for small values of the baryon chemical potential.\nThe next-to-leading order correction to $\\kappa_B\\sigma_B^2$ however is\napproximately three times larger than that for $S_B\\sigma_B$. The former thus\ndrops much more rapidly with increasing beam energy, $\\sqrt{s_{NN}}$. We argue\nthat these generic patterns are consistent with current data on cumulants of\nnet-proton number fluctuations measured by the STAR Collaboration at\n$\\sqrt{s_{NN}}\\ge 19.6$~GeV."
    },
    {
        "anchor": "Curvature of the phase transition line in the mu-T plane: We determined the curvature of the phase transition line in the mu-T plane\nusing a Taylor expansion in mu. The Polyakov loop and the strange quark number\nsusceptibility were measured to locate the pseudocritical line. The analysis\nwas carried out on Nt=4,6,8,10 lattices generated with a Symanzik improved\ngauge and stout-link improved (2+1) flavour staggered fermion action using\nphysical quark masses.",
        "positive": "Trouble shooting for covariance fitting in highly correlated data: We report a possible solution to the trouble that the covariance fitting\nfails when the data is highly correlated and the covariance matrix has small\neigenvalues. As an example, we choose the data analysis of highly correlated\n$B_K$ data on the basis of the SU(2) staggered chiral perturbation theory.\nBasically, the essence of the problem is that we do not have an accurate\nfitting function so that we cannot fit the highly correlated and precise data.\nWhen some eigenvalues of the covariance matrix are small, even a tiny error of\nfitting function can produce large chi-square and spoil the fitting procedure.\nWe have applied a number of prescriptions available in the market such as\ndiagonal approximation and cutoff method. In addition, we present a new method,\nthe eigenmode shift method which fine-tunes the fitting function while keeping\nthe covariance matrix untouched."
    },
    {
        "anchor": "Calculating the hadronic vacuum polarization and leading hadronic\n  contribution to the muon anomalous magnetic moment with improved staggered\n  quarks: We present a lattice calculation of the hadronic vacuum polarization and the\nlowest-order hadronic contribution to the muon anomalous magnetic moment, a_\\mu\n= (g-2)/2, using 2+1 flavors of improved staggered fermions. A precise fit to\nthe low-q^2 region of the vacuum polarization is necessary to accurately\nextract the muon g-2. To obtain this fit, we use staggered chiral perturbation\ntheory, including the vector particles as resonances, and compare these to\npolynomial fits to the lattice data. We discuss the fit results and associated\nsystematic uncertainties, paying particular attention to the relative\ncontributions of the pions and vector mesons. Using a single lattice spacing\nensemble (a=0.086 fm), light quark masses as small as roughly one-tenth the\nstrange quark mass, and volumes as large as (3.4 fm)^3, we find a_\\mu^{HLO} =\n(713 \\pm 15) \\times 10^{-10} and (748 \\pm 21) \\times 10^{-10} where the error\nis statistical only and the two values correspond to linear and quadratic\nextrapolations in the light quark mass, respectively. Considering systematic\nuncertainties not eliminated in this study, we view this as agreement with the\ncurrent best calculations using the experimental cross section for e^+e^-\nannihilation to hadrons, 692.4 (5.9) (2.4)\\times 10^{-10}, and including the\nexperimental decay rate of the tau lepton to hadrons, 711.0 (5.0)\n(0.8)(2.8)\\times 10^{-10}. We discuss several ways to improve the current\nlattice calculation.",
        "positive": "The fluctuational region on the phase diagram of lattice Weinberg -\n  Salam model: The lattice Weinberg - Salam model without fermions is investigated\nnumerically for the realistic choice of bare coupling constants correspondent\nto the value of the Weinberg angle $\\theta_W \\sim 30^o$, and the fine structure\nconstant $\\alpha \\sim {1/100}$. On the phase diagram there exists the vicinity\nof the phase transition between the physical Higgs phase and the unphysical\nsymmetric phase, where the fluctuations of the scalar field become strong. The\nclassical Nambu monopole can be considered as an embryo of the unphysical\nsymmetric phase within the physical phase. In the fluctuational region quantum\nNambu monopoles are dense and, therefore, the perturbation expansion around\ntrivial vacuum cannot be applied. The maximal value of the cutoff at the given\nvalues of coupling constants calculated using the lattices of sizes $8^3\\times\n16$, $12^3\\times 16$, and $16^4$ is $\\Lambda_c \\sim 1.4 \\pm 0.2$ Tev. As the\nlattice sizes used are rather small we consider this result as preliminary."
    },
    {
        "anchor": "Exact relation of lattice and continuum parameters in three-dimensional\n  SU(2)+Higgs theories: The essential features of the high-temperature electroweak phase transition\nare contained in a three-dimensional super-renormalizable effective field\ntheory. We calculate the exact counterterms needed for lattice simulations of\nthe SU(2)-part of this theory. Scalar fields in both fundamental and adjoint\nrepresentations are included. The three-dimensional U(1)+Higgs theory is also\ndiscussed.",
        "positive": "Status Report on ILDG activities: A status report about the International Lattice Data Grid (ILDG) is given.\nDifferent countries participating in the ILDG have created regional lattice\ndata grid solutions that are implemented, working and used. The remaining task\nand the focus of present activities is the development of the interoperability\nof these regional grids. A first, successful step in this direction is a\nmetadata catalogue service which is already working interoperable."
    },
    {
        "anchor": "Partial-wave and helicity operators for the scattering of two hadrons in\n  lattice QCD: Partial-wave operators for lattice QCD are developed in order to facilitate\nthe identification of the spins of two-hadron scattering states corresponding\nto zero total momentum. Taking the periodic boundary conditions for lattice\nstates into account, orthogonal sets of partial-wave operators for orbital\nangular momentum are identified. When combined with the intrinsic spins of the\nhadrons, orthogonal sets of parent operators for total angular momentum $J$ and\nprojection $M$ are obtained. The parent operators are subduced to irreducible\nrepresentations of the octahedral group in order to obtain descendant operators\nfor use in lattice calculations. The descendant operators retain orthogonality\nwith respect to $J$. The spin of a state can be identified by the spin of\nparent operators that dominate creation of the state. For nonzero total\nmomentum, operators are developed for a range of helicities and they are\nsubduced to irreducible representations corresponding to the different\ndirections of total momentum. Sets of operators that include a sufficient range\nof helicities allow identification of spin $J$ when a state couples to\noperators with helicities less than or equal to $J$, but not to operators with\nhigher helicities.",
        "positive": "Status of and performance estimates for QCDOC: QCDOC is a supercomputer designed for high scalability at a low cost per\nnode. We discuss the status of the project and provide performance estimates\nfor large machines obtained from cycle accurate simulation of the QCDOC ASIC."
    },
    {
        "anchor": "Polyakov Loops and Magnetic Screening from Monopoles in SU(2) Lattice\n  Gauge Theory: We present results from magnetic monopoles in $SU(2)$ lattice gauge theory at\nfinite temperature. The lattices are $16^{3}\\times N_{t}$, for\n$N_{t}=4,6,8,12$, at $\\beta=2.5115$. Quantities discussed are: the spacial\nstring tension, Polyakov loops, and the screening of timelike and spacelike\nmagnetic currents.",
        "positive": "SU(3) lattice gauge autocorrelations with anisotropic action: We report results of autocorrelation measurements in pure $SU(3)$ lattice\ngauge theory. The computations are performed on the {\\sc convex spp1200}\nparallel platform within the {\\sc canopy} programming environment. The focus of\nour analysis is on typical autocorrelation times and optimization of the mixing\nratio between overrelaxation and pseudo-heatbath sweeps for generating gauge\nfield configurations. We study second order tadpole-improved approximations of\nthe Wilson action in the gluon sector, which offers the advantage of working on\nsmaller lattices ($8^3~\\times~16$ and $6^3~\\times$~12~--~30). We also make use\nof anisotropic lattices, with temporal lattice spacing smaller than the spatial\nspacing, which prove useful for calculating noisy correlation functions with\nlarge spatial lattice discretization (of the order of 0.4 fm)."
    },
    {
        "anchor": "Blocking of Dynamical Triangulations with Matter: We use the recently proposed node decimation algorithm for blocking dynamical\ngeometries to investigate a class of models, with central charge greater than\nunity, coupled to 2D gravity. We demonstrate that the blocking preserves the\nfractal structure of the surfaces.",
        "positive": "Kaon and D meson semileptonic form factors from lattice QCD: We present the status of on-going calculations of the $K\\to\\pi l\\nu$ and\n$D\\to K(\\pi) l\\nu$ semileptonic form factors at $q^2=0$. These form factors are\nimportant for the determination of the CKM matrix elements\n$\\lvert{V_{us}}\\rvert$ and $\\lvert{V_{cs(d)}}\\rvert$ respectively. This work\nuses the HISQ action for both valence quarks and sea quarks on MILC $N_f=2+1+1$\nconfigurations. We employ twisted boundary conditions to calculate the form\nfactors at zero momentum transfer directly. The $K\\to\\pi$ results are an update\nto previously published results with new data at the physical point. The $D\\to\nK(\\pi)$ results are preliminary."
    },
    {
        "anchor": "An Almost Perfect Lattice Action for infrared QCD: A block-spin transformation on the dual lattice leads us to an almost perfect\nlattice action for monopoles and strings in QCD. The perfect operator for a\nstatic quark potential is fixed when we compare the above action with the\nperfect action obtained analytically after infinite-step block-spin\ntransformations in a simple case. The continuum rotational invariance is\nrestored and the physical value of the string tension is reproduced fairly\nwell. Gauge independence of the abelian and the monopole scenario is discussed.",
        "positive": "In-medium dispersion relations of charmonia studied by maximum entropy\n  method: We study in-medium spectral properties of charmonia in the vector and\npseudoscalar channels at nonzero momenta on quenched lattices, especially\nfocusing on their dispersion relation and weight of the peak. We measure the\nlattice Euclidean correlation functions with nonzero momenta on the anisotropic\nquenched lattices and study the spectral functions with the maximum entropy\nmethod. The dispersion relations of charmonia and the momentum dependence of\nthe weight of the peak are analyzed with the maximum entropy method together\nwith the errors estimated probabilistically in this method. We find significant\nincrease of the masses of charmonia in medium. It is also found that the\nfunctional form of the charmonium dispersion relations is not changed from that\nin the vacuum within the error even at $T\\simeq1.6T_c$ for all the channels we\nanalyzed."
    },
    {
        "anchor": "Finite-volume energy shift of the three-nucleon ground state: A perturbative calculation of the three-nucleon ground-state energy shift in\na finite volume is carried out within the non-relativistic effective theory.\nThe energy shift is evaluated up to and including $\\mathcal{O}(L^{-6})$, where\n$L$ is the size of a cubic box. The convergence of the perturbative series at\nphysical values of the scattering lengths is studied numerically.",
        "positive": "The b quark mass from lattice nonrelativistic QCD: We present the first two-loop calculation of the heavy quark energy shift in\nlattice nonrelativistic QCD (NRQCD). This calculation allow us to extract a\npreliminary prediction of $m_b(m_b, n_f = 5) = 4.25(12)$ GeV for the mass of\nthe b quark from lattice NRQCD simulations performed with a lattice of spacing\n$a=0.12$fm. Our result is an improvement on a previous determination of the b\nquark mass from unquenched lattice NRQCD simulations, which was limited by the\nuse of one-loop expressions for the energy shift. Our value is in good\nagreement with recent results of $m_b(m_b) = 4.163(16)$ GeV from QCD sum rules\nand $m_b(m_b, n_f = 5) = 4.170(25)$ GeV from realistic lattice simulations\nusing highly-improved staggered quarks. We employ a mixed strategy to simplify\nour calculation. Ghost, gluon and counterterm contributions to the energy shift\nand mass renormalisation are extracted from quenched high-beta simulations\nwhilst fermionic contributions are calculated using automated lattice\nperturbation theory. Our results demonstrate the effectiveness of such a\nstrategy."
    },
    {
        "anchor": "Gauge-independent \"Abelian\" and magnetic-monopole dominance, and the\n  dual Meissner effect in lattice $SU(2)$ Yang-Mills theory: In the $SU(2)$ Yang-Mills theory on the four-dimensional Euclidean lattice,\nwe confirm the gauge-independent \"Abelian\" dominance (or the restricted field\ndominance) and gauge-independent magnetic-monopole dominance in the string\ntension of the linear potential extracted from the Wilson loop in the\nfundamental representation. The dual Meissner effect is observed by\ndemonstrating the squeezing of the chromoelectric field flux connecting a pair\nof quark and antiquark. In addition, the circular magnetic-monopole current is\ninduced around the chromoelectric flux. The type of the dual superconductivity\nis also determined by fitting the result with the dual Ginzburg-Landau model.\nThus the dual superconductor picture for quark confinement is supported in a\ngauge-independent manner. These results are obtained based on a reformulation\nof the lattice Yang-Mills theory based on the change of variables a la\nCho-Duan-Ge-Faddeev-Niemi combined with a non-Abelian Stokes theorem for the\nWilson loop operator. We give a new procedure (called the reduction) for\nobtaining the color direction field which plays the central role in this\nreformulation.",
        "positive": "Charmonium-nucleon interactions from the time-dependent HAL QCD method: The charmonium-nucleon effective central interactions have been computed by\nthe time-dependent HAL QCD method. This gives an updated result of a previous\nstudy based on the time-independent method, which is now known to be\nproblematic because of the difficulty in achieving the ground-state saturation.\nWe discuss that the result is consistent with the heavy quark symmetry. No\nbound state is observed from the analysis of the scattering phase shift;\nhowever, this shall lead to a future search of the hidden-charm pentaquarks by\nconsidering channel-coupling effects."
    },
    {
        "anchor": "Static quark anti-quark free and internal energy in 2-flavor QCD and\n  bound states in the QGP: We present results on heavy quark free energies in 2-flavour QCD. The\ntemperature dependence of the interaction between static quark anti-quark pairs\nwill be analyzed in terms of temperature dependent screening radii, which give\na first estimate on the medium modification of (heavy quark) bound states in\nthe quark gluon plasma. Comparing those radii to the (zero temperature) mean\nsquared charge radii of cha rmonium states indicates that the $J/\\psi$ may\nsurvive the phase transition as a bound state, while $\\chi_c$ and $\\psi'$ are\nexpected to show significant thermal modifications at temperatures close to the\ntransition. Furthermore we will analyze the relation between heavy quark free\nenergies, entropy contributions and internal energy and discuss their relation\nto potential models used to analyze the melting of heavy quark bound states\nabove the deconfinement temperature. Results of different groups and various\npotential models for bound states in the deconfined phase of QCD are compared.",
        "positive": "Topological Phases in Neuberger-Dirac operator: The response of the Neuberger-Dirac fermion operator $D=\\Id + V$ in the\ntopologically nontrivial background gauge field depends on the negative mass\nparameter $m_0$ in the Wilson-Dirac fermion operator $D_w$ which enters $D$\nthrough the unitary operator $V = D_w (D_w^{\\dagger} D_w)^{-1/2}$. We classify\nthe topological phases of $D$ by comparing its index to the topological charge\nof the smooth background gauge field. An exact discrete symmetry in the\ntopological phase diagram is proved for any gauge configurations. A formula for\nthe index of D in each topological phase is derived by obtaining the total\nchiral charge of the zero modes in the exact solution of the free fermion\npropagator."
    },
    {
        "anchor": "Screening of heavy quark free energies at finite temperature and\n  non-zero baryon chemical potential: We analyze the dependence of heavy quark free energies on the baryon chemical\npotential (mu_b) in 2-flavour QCD using improved (p4) staggered fermions with a\nbare quark mass of m/T = 0.4. By performing a 6th order Taylor expansion in the\nchemical potential which circumvents the sign problem. The Taylor expansion\ncoefficients of colour singlet and colour averaged free energies are calculated\nand from this the expansion coefficients for the corresponding screening masses\nare determined. We find that for small mu_b the free energies of a static quark\nanti-quark pair decrease in a medium with a net excess of quarks and that\nscreening is well described by a screening mass which increases with increasing\nmu_b. The mu_b-dependent corrections to the screening masses are well described\nby perturbation theory for T > 2 T_c. In particular, we find for all\ntemperatures above T_c that the expansion coefficients for singlet and colour\naveraged screening masses differ by a factor 2.",
        "positive": "Applicability of the two-particle quantization condition to\n  partially-quenched theories: Partial quenching allows one to consider correlation functions and amplitudes\nthat do not arise in the corresponding unquenched theory. For example, physical\n$s$-wave pion scattering can be decomposed into $I=0$ and $2$ amplitudes,\nwhile, in a partially-quenched extension, the larger symmetry group implies\nthat there are more than two independent scattering amplitudes. It has been\nproposed that the finite-volume quantization condition of L\\\"uscher holds for\nthe correlation functions associated with each of the two-particle amplitudes\nthat arise in partially-quenched theories. Using partially-quenched chiral\nperturbation theory, we show that this proposal fails for those correlation\nfunctions for which the corresponding one-loop amplitudes do not satisfy\n$s$-wave unitarity. For partially-quenched amplitudes that, while being\nunphysical, do satisfy one-loop $s$-wave unitarity, we argue that the proposal\nis plausible. Implications for previous work are discussed."
    },
    {
        "anchor": "Quantum Operator Design for Lattice Baryon Spectroscopy: A previously-proposed method of constructing spatially-extended\ngauge-invariant three-quark operators for use in Monte Carlo lattice QCD\ncalculations is tested, and a methodology for using these operators to extract\nthe energies of a large number of baryon states is developed. This work is part\nof a long-term project undertaken by the Lattice Hadron Physics Collaboration\nto carry out a first-principles calculation of the low-lying spectrum of QCD.\n  These techniques are then applied in the construction of nucleon operators.\nCorrelation matrix elements between these operators are estimated using 200\nconfigurations on a $12^3 \\times 48$ anisotropic lattice in the quenched\napproximation with unphysically heavy u, d quark masses (the pion mass is\napproximately 700 MeV). After a change of basis operators using a variational\nmethod is applied, the energies of up to eight states are extracted in each\nsymmetry channel.\n  Although comparison with experiment is not justified, the pattern of levels\nobtained qualitatively agrees with the observed spectrum. A comparison with\nquark model predictions is also made; the quark model predicts more low-lying\neven-parity states than this study yields, but both the quark model and this\nstudy predict more odd-parity states near 2 GeV than currently observed in\nexperiments.",
        "positive": "Monte Carlo Study of the 3D Thirring Model: I review three different non-perturbative approaches to the three dimensional\nThirring model: the 1/N_f expansion, Schwinger-Dyson equations, and Monte Carlo\nsimulation. Simulation results are presented to support the existence of a\nnon-perturbative fixed point at a chiral symmetry breaking phase transition for\nN_f=2 and 4, but not for N_f=6. Spectrum calculations for $N_f=2$ reveal\nconventional level ordering near the transition."
    },
    {
        "anchor": "Chiral properties of the fixed point action of the Schwinger model: We study the spectrum properties for a recently constructed fixed point\nlattice Dirac operator. We also consider the problem of the extraction of the\nfermion condensate, both by direct computation, and through the Banks-Casher\nformula by analyzing the density of eigenvalues of a redefined antihermitean\nlattice Dirac operator.",
        "positive": "A class of chiral fermion models: We study the relation between the Roma and Zaragoza proposals for chiral\nfermions on the lattice. The fermion action in the Roma approach is shown to be\nequivalent to one of the Zaragoza type. This result is used to perform a\nmean-field study of the phase diagram for chiral Yukawa models based on the\nRoma action. The phase diagram is compared with the one based on the Zaragoza\nmodel with the most local choice for the fermion interactions."
    },
    {
        "anchor": "Toward dense QCD in quantum computers: Lattice QCD at nonzero baryon density is a big challenge in hadron physics.\nIn this presentation, I discuss the quantum computation of lattice gauge theory\nat nonzero density. I show some benchmark results of the Schwinger model\nobtained by the quantum adiabatic algorithm and the quantum variational\nalgorithm.",
        "positive": "Renormalization constants for Wilson fermion lattice QCD with four\n  dynamical flavours: We report on an ongoing non-perturbative computation of RI-MOM scheme\nrenormalization constants for the lattice action with four dynamical flavours\ncurrently in use by ETMC. For this goal dedicated simulations with four\ndegenerate sea quark flavours are performed at several values of the standard\nand twisted quark mass parameters. We discuss a method for removing possible\nO(a) artifacts at all momenta and extrapolating renormalization constant\nestimators to the chiral limit. We give preliminary results at one lattice\nspacing."
    },
    {
        "anchor": "CP violation in QCD: Among the parameters of QCD is one that results in CP violation when\nnon-vanishing. This is closely related to possible quark mass terms. It is\nconventionally interpreted in terms of gauge field topology or alternatively in\nterms of phases in the quark masses. There is no experimental evidence for this\nparameter having a non-zero value, a puzzle for theories involving unification.",
        "positive": "Overview from lattice QCD: I review recent Lattice results. In particular, the confinement mechanism and\nstring breaking, glueballs and hybrid mesons as well as light hadron\nspectroscopy are discussed."
    },
    {
        "anchor": "Towards High-Precision Parton Distributions From Lattice QCD via\n  Distillation: We apply the Distillation spatial smearing program to the extraction of the\nunpolarized isovector valence PDF of the nucleon. The improved volume sampling\nand control of excited-states afforded by distillation leads to a dramatically\nimproved determination of the requisite Ioffe-time Pseudo-distribution (pITD).\nThe impact of higher-twist effects is subsequently explored by extending the\nWilson line length present in our non-local operators to one half the spatial\nextent of the lattice ensemble considered. The valence PDF is extracted by\nanalyzing both the matched Ioffe-time Distribution (ITD), as well as a direct\nmatching of the pITD to the PDF. Through development of a novel prescription to\nobtain the PDF from the pITD, we establish a concerning deviation of the pITD\nfrom the expected DGLAP evolution of the pseudo-PDF. The presence of DGLAP\nevolution is observed once more following introduction of a discretization term\ninto the PDF extractions. Observance and correction of this discrepancy further\nhighlights the utility of distillation in such structure studies.",
        "positive": "A complete non-perturbative renormalization prescription for quasi-PDFs: In this work we present, for the first time, the non-perturbative\nrenormalization for the unpolarized, helicity and transversity quasi-PDFs, in\nan RI' scheme. The proposed prescription addresses simultaneously all aspects\nof renormalization: logarithmic divergences, finite renormalization as well as\nthe linear divergence which is present in the matrix elements of fermion\noperators with Wilson lines. Furthermore, for the case of the unpolarized\nquasi-PDFs, we describe how to eliminate the unwanted mixing with the twist-3\nscalar operator. We utilize perturbation theory for the one-loop conversion\nfactor that brings the renormalization functions to the MS-scheme at a scale of\n2 GeV. We also explain how to improve the estimates on the renormalization\nfunctions by eliminating lattice artifacts. The latter can be computed in\none-loop perturbation theory and to all orders in the lattice spacing. We apply\nthe methodology for the renormalization to an ensemble of twisted mass fermions\nwith Nf=2+1+1 dynamical light quarks, and a pion mass of around 375 MeV."
    },
    {
        "anchor": "The Gluon Propagator at High Temperature: We study the gluon propagator in Landau gauge in the deconfined phase of\n$SU(2)$ gauge theory. From the long-distance behaviour of correlation functions\nof temporal and spatial components of the gauge fields we extract electric\n($m_e$) and magnetic ($m_m$) screening masses. For temperatures larger than\ntwice $T_c$ we find no additional temperature dependence in $m_e(T)/T$, while\n$m_m(T)/T$ drops with increasing temperature. The decrease is consistent with\nthe expected behaviour, $m_m(T) \\sim g^2(T)T$. We find $m_e(T) = 2.484(52)T$\nand $m_m(T) = 0.466(15) g^2(T) T$.",
        "positive": "Form factors for semi-leptonic $B$ decays: Semi-leptonic $B$ decays provide promising channels to test the Standard\nModel, search for signs of new physics, or determine fundamental parameters\nlike CKM matrix elements. We present an update on our calculation of short\ndistance contributions to GIM suppressed rare $B$ decays focusing in particular\non $B_s\\to \\phi \\ell^+ \\ell^-$ decays. Furthermore we show first results for\nour calculation of $B_{(s)}\\to D_{(s)}^{(*)}\\ell\\nu$ semi-leptonic decays\ninvolving $b\\to c$ transitions. Our calculations are based on RBC-UKQCD's 2+1\nflavor domain-wall fermion and Iwasaki gauge field configurations featuring\nthree lattice spacings in the range $1.73$ GeV $\\le a^{-1} \\le 2.77$ GeV and\npion masses down to the physical value. We calculate the form factors by\nsimulating $b$-quarks using the relativistic heavy quark action, create light\n$u/d$ and $s$ quarks with standard domain-wall kernel, and use optimised\nM\\\"obius domain-wall fermions for charm quarks."
    },
    {
        "anchor": "A QUDA-branch to compute disconnected diagrams in GPUs: Although QUDA allows for an efficient computation of many QCD quantities, it\nis surprinsingly lacking tools to evaluate disconnected diagrams, for which\nGPUs are specially well suited. We aim to fill this gap by creating our own\nbranch of QUDA, which includes new kernels and functions required to calculate\nfermion loops using several methods and fermionic regularizations.",
        "positive": "Scalar-matter-gluon interaction: A full non-perturbative treatment of gauge theories requires to include\nmatter fields on equal footing with the gauge fields. Scalar matter can act as\na role model for generic matter, as many questions, e.g. confinement, can be\nposed without referring to a particular Lorentz structure. Due to their rather\nsimple structure they are also useful to develop methods.\n  One possible way to describe gauge theories beyond perturbation theory is\nbased on correlation functions. After a short discussion of the setup, lattice\ngauge theory is used to analyze the interaction of gluons with quenched\nfundamental and adjoint scalars. Both the two-point and three-point correlation\nfunctions for massive and massless adjoint and fundamental scalars will be\ndetermined, in minimal Landau gauge. The findings are in agreement with the\npossibility that scalars are only slightly affected by the interaction with\ngluons. The results are compared briefly with dynamical, massive scalars,\nshowing no significant changes in the confinement region compared to the\nquenched case."
    },
    {
        "anchor": "Quark Confinement and Surface Critical Phenomena: Surface critical phenomena and the related onset of Goldstone modes probe the\nfundamental properties of the confining flux in Quantum Chromodynamics. New\nideas on surface roughening and their implications for lattice studies of quark\nconfinement are presented. Problems with the oversimplified string description\nof the Wilson flux sheet are discussed.",
        "positive": "The Glue Content of the Pion: We perform a quenched computation of the glue momentum fraction in the pion.\nDifferent discretizations of the gluonic energy-momentum tensor are studied on\nthe lattice for that purpose. We discuss some implications based on the\nmomentum sum rule. Finally we point out promising applications of the\ntechniques developed here."
    },
    {
        "anchor": "Potential between adjoint sources in arbitrary representations: The potential between sources in arbitrary representations of the gauge group\nis studied on an anisotropic lattice in a spherical model approximation. It is\nshown analytically that for half-integer $j$ and $j'$ in the confinement phase\nthe potential rises linearly, whereas for integer $j$ and half-integer $j'$ it\nrises infinitely which means a strong suppression of the combination of such\nstates . For integer $j$ and $j'$ the potential shows Debay screening and\nCoulomb behavior in the deconfinement phase >. It is also shown, that\n$<\\chi^{(j)}> \\backsim <\\chi>^{2j}$ when $<\\chi> \\gtrsim1$ and is in agreement\nwith the mean field theory prediction, and $<\\chi^{(j)}> \\backsim <\\chi>$ for\n$<\\chi> \\lesssim1$ which agrees with MC experiment. String tension\nmodel-computed for sources invariant under center group transformations\ndemonstrates Casimir scaling in the intermediate distance regime and turns into\nzero at large distances.",
        "positive": "Bianchi Identities and Degeneracy of Chromomagnetic Fields in SU(2)\n  Gluodynamics: We investigate the non-Abelian Bianchi identities in pure SU(2) lattice\nYang-Mills theory in three and four dimensions. The non-Abelian Stokes theorem\nproposed recently allows to formulate the Bianchi identities in terms of local\nphysical fluxes. Then the violation of Bianchi identities becomes a well\ndefined concept ultimately related to chromomagnetic fields degeneracy points.\nWe present numerical evidences that in D=4 the suppression of the Bianchi\nidentities violation destroys confinement while the removal of the degeneracy\npoints drives the theory to the topologically non-trivial sector."
    },
    {
        "anchor": "Scaling in Steiner Random Surfaces: It has been suggested that the modified Steiner action functional has\ndesirable properties for a random surface action. In this paper we investigate\nthe scaling of the string tension and massgap in a variant of this action on\ndynamically triangulated random surfaces and compare the results with the\ngaussian plus extrinsic curvature actions that have been used previously.",
        "positive": "The universal effective potential for three-dimensional massive scalar\n  field theory from the Monte Carlo study of the Ising model: We study the low-energy effective action $S_{eff}[\\varphi]$ for the\none-component real scalar field theory in three Euclidean dimensions in the\nsymmetric phase, concentrating on its static part --- effective potential\n$V_{eff}(\\varphi)$. It characterizes the approach to the phase transition in\nall systems that belong to the 3d Ising universality class. We compute it from\nthe probability distributions of the average magnetization in the 3d Ising\nmodel in a homogeneous external field, obtained by Monte Carlo. We find that\nthe $\\varphi^6$ term in $V_{eff}$ is important, while the higher terms can be\nneglected within our statistical errors. Thus we obtain the approximate\neffective action $$ S_{eff} = \\int d^3 x \\left\\{\n  {1 \\over 2} \\partial_\\mu \\varphi \\partial_\\mu \\varphi +\n  {1 \\over 2} m^2 \\varphi^2 + m g_4 \\varphi^4 + g_6 \\varphi^6 \\right\\} , $$\nwith arbitrary mass $m$ that sets the scale, and dimensionless couplings $g_4 =\n0.97 \\pm 0.02$ and $g_6 = 2.05 \\pm 0.15$. The value of $g_4$ is consistent with\nthe renormalization group fixed point coupling. This $V_{eff}$, when used\ninstead of the traditional $a \\varphi^2 + b \\varphi^4$, turns the\nGinzburg--Landau description of the long-wave properties of the 3d theory near\ncriticality into quantitatively accurate. It is also relevant to the theory of\ncosmological phase transitions."
    },
    {
        "anchor": "Complex Langevin dynamics in the SU(3) spin model at nonzero chemical\n  potential revisited: The three-dimensional SU(3) spin model is an effective Polyakov loop model\nfor QCD at nonzero temperature and density. It suffers from a sign problem at\nnonzero chemical potential. We revisit this model using complex Langevin\ndynamics and assess in particular the justification of this approach, using\nanalyticity at small mu^2 and the criteria for correctness developed recently.\nFinite-stepsize effects are discussed in some detail and a higher-order\nalgorithm is employed to eliminate leading stepsize corrections. Our results\nstrongly indicate that complex Langevin dynamics is reliable in this theory in\nboth phases, including the critical region. This is in sharp contrast to the\ncase of the XY model, where correct results were obtained in only part of the\nphase diagram.",
        "positive": "Strong coupling expansion for Yang-Mills theory at finite temperature: Euclidean strong coupling expansion of the partition function is applied to\nlattice Yang-Mills theory at finite temperature, i.e. for lattices with a\ncompactified temporal direction. The expansions have a finite radius of\nconvergence and thus are valid only for $\\beta<\\beta_c$, where $\\beta_c$\ndenotes the nearest singularity of the free energy on the real axis. The\naccessible temperature range is thus the confined regime up to the\ndeconfinement transition. We have calculated the first few orders of these\nexpansions of the free energy density as well as the screening masses for the\ngauge groups SU(2) and SU(3). The resulting free energy series can be summed up\nand corresponds to a glueball gas of the lowest mass glueballs up to the\ncalculated order. Our result can be used to fix the lower integration constant\nfor Monte Carlo calculations of the thermodynamic pressure via the integral\nmethod, and shows from first principles that in the confined phase this\nconstant is indeed exponentially small. Similarly, our results also explain the\nweak temperature dependence of glueball screening masses below $T_c$, as\nobserved in Monte Carlo simulations. Possibilities and difficulties in\nextracting $\\beta_c$ from the series are discussed."
    },
    {
        "anchor": "Generalized Parton Distributions from Lattice QCD: In recent years, there has been a breakthrough in lattice calculations of\n$x$-dependent partonic distributions. This encompasses also distributions\ndescribing the 3D structure of the nucleon, such as generalized parton\ndistributions (GPDs). We report a new method of accessing GPDs in asymmetric\nframes of reference, relying on a novel Lorentz-covariant parametrization of\nthe accessed off-forward matrix elements in boosted nucleon states. The\napproach offers the possibility of computationally more efficient determination\nof the full parameter dependence of GPDs and as such, it can contribute to\nbetter understanding of nucleon's structure.",
        "positive": "An Improved Single-Plaquette Gauge Action: We describe and test a nonperturbatively improved single-plaquette lattice\naction for 4-d SU(2) and SU(3) pure gauge theory, which suppresses large\nfluctuations of the plaquette, without requiring the naive continuum limit for\nsmooth fields. We tune the action parameters based on torelon masses in\nmoderate cubic physical volumes, and investigate the size of cut-off effects in\nother physical quantities, including torelon masses in asymmetric spatial\nvolumes, the static quark potential, and gradient flow observables. In 2-d O(N)\nmodels similarly constructed nearest-neighbor actions have led to a drastic\nreduction of cut-off effects, down to the permille level, in a wide variety of\nphysical quantities. In the gauge theories, we find significant reduction of\nlattice artifacts, and for some observables, the coarsest lattice result is\nvery close to the continuum value. We estimate an improvement factor of 40\ncompared to using the Wilson gauge action to achieve the same statistical\naccuracy and suppression of cut-off effects. The simplicity of the gauge action\nmakes it amenable for dynamical fermion simulations."
    },
    {
        "anchor": "Anisotropic lattices for precision computations in heavy flavor physics: We study the anisotropic lattice QCD for precision computations of\nheavy-light matrix elements. Our previous study in which the lattices are\ncalibrated with a few percent accuracy has already given results comparable to\nthe existing calculations. This suggests that even higher precision may be\nachieved by a more precise calibration of anisotropic lattices. We describe our\nstrategy to tune the gauge and quark parameters with accuracies much less than\n1 % in the quenched approximation.",
        "positive": "Computers for Lattice QCD: The architecture and capabilities of the computers currently in use for\nlarge-scale lattice QCD calculations are described and compared. Based on this\npresent experience, possible future directions are discussed."
    },
    {
        "anchor": "D-decays with unquenched Lattice QCD: We discuss the recent progress in computing the D-meson decay constant and\nD->pi l nu form factors from the lattice QCD simulations with Nf=2 dynamical\nusing Wilson quarks. We report fD=201(20)MeV and F+(1GeV^2)/fD=4.04(78)GeV^-1\nat a=0.08fm.",
        "positive": "Nonperturbative running of the tensor operator for $N_\\rm{f}=3$ QCD from\n  the chirally rotated Schr\u00f6dinger Functional: We study the Renormalisation Group (RG) running of the non-singlet tensor\noperator, for $N_\\mathrm{\\scriptstyle f}=3$ QCD with Wilson fermions in a mixed\naction setup, with standard Schr\\\"odinger Functional (SF) boundary conditions\nfor sea quarks and chirally rotated Schr\\\"odinger Functional ($\\chi$SF)\nboundary conditions for valence quarks. Based on a recursive finite-size\nscaling technique we compute non-perturbatively the tensor step-scaling\nfunction for an energy range between a hadronic scale and an electroweak scale,\nabove which perturbation theory may be safely applied. Our result is expressed\nas the RG-running factor $T^{\\mathrm{RGI}}/[\nT(\\mu_{\\mathrm{had}})]_{\\scriptstyle \\rm R}$, where the numerator is the scale\nindependent (Renormalisation Group Invariant - RGI) tensor operator and the\ndenominator is its renormalised counterpart at a hadronic scale\n$\\mu_{\\mathrm{had}} = 233(8)$~MeV in a given scheme. We determine the\nstep-scaling function in four distinct renormalisation schemes. We also compute\nthe renormalisation parameters of these schemes at $\\mu_{\\mathrm{had}}$ which,\ncombined with the RG-running factor, gives the scheme-independent quantity\n$Z^{\\mathrm{RGI}}_{\\mathrm T}(g_0^2)$ in four schemes and for a range of bare\ngauge couplings in which large volume hadronic matrix element simulations are\nperformed by the CLS consortium in $N_\\mathrm{\\scriptstyle f}=2+1$ QCD. All\nfour results are compatible and also agree with a recent determination based on\na unitary setup for Wilson quarks with Schr\\\"odinger Functional boundary\nconditions~arXiv:2309.04314 . This provides a strong universality test."
    },
    {
        "anchor": "Study of H-dibaryon mass in Lattice QCD: After a brief review of discovery of the H-dibaryon in lattice QCD, effect of\nthe flavor SU(3) symmetry breaking on the H-dibaryon is studied by basing on\nthe baryon-baryon (BB) interactions extracted from QCD on the lattice. The\nSchrodinger equation for Lambda Lambda - N Xi -Sigma Sigma coupled-channel is\nsolved with the physical baryon masses and the potentials obtained from QCD at\nthe flavor SU(3) limit. A resonant H-dibaryon is found between Lambda Lambda\nand N Xi thresholds in this treatment.",
        "positive": "Chiral fermion in the Hamiltonian lattice gauge theory: We discuss the chiral fermion in the Hamiltonian formalism of lattice gauge\ntheory. Although the naive chiral charge operator does not commute with the\nHamiltonian, the commutable one can be defined for the overlap fermion. The\neigenvalues of the energy and the chiral charge can be defined simultaneously.\nWe study how the eigenvalue spectrum reflects chiral properties of systems,\nsuch as a chiral chemical potential and the axial anomaly. We also show that\nthe Wilson fermion is a chiral fermion in one dimension."
    },
    {
        "anchor": "Crumpled triangulations and critical points in 4D simplicial quantum\n  gravity: This is an expanded and revised version of our geometrical analysis of the\nstrong coupling phase of 4D simplicial quantum gravity. The main differences\nwith respect to the former version is a full discussion of singular\ntriangulations with singular vertices connected by a subsingular edge. In\nparticular we provide analytical arguments which characterize the entropical\nproperties of triangulations with a singular edge connecting two singular\nvertices. The analytical estimate of the location of the critical coupling at\nk_2\\simeq 1.3093 is presented in more details. Finally we also provide a model\nfor pseudo-criticality at finite N_4(S^4).",
        "positive": "Another Look at Neural Multigrid: We present a new multigrid method called neural multigrid which is based on\njoining multigrid ideas with concepts from neural nets. The main idea is to use\nthe Greenbaum criterion as a cost functional for the neural net. The algorithm\nis able to learn efficient interpolation operators in the case of the ordered\nLaplace equation with only a very small critical slowing down and with a\nsurprisingly small amount of work comparable to that of a Conjugate Gradient\nsolver. In the case of the two-dimensional Laplace equation with SU(2) gauge\nfields at beta=0 the learning exhibits critical slowing down with an exponent\nof about z = 0.4. The algorithm is able to find quite good interpolation\noperators in this case as well. Thereby it is proven that a practical true\nmultigrid algorithm exists even for a gauge theory. An improved algorithm using\ndynamical blocks that will hopefully overcome the critical slowing down\ncompletely is sketched."
    },
    {
        "anchor": "Softening Transitions with Quenched 2D Gravity: We perform extensive Monte Carlo simulations of the 10-state Potts model on\nquenched two-dimensional $\\Phi^3$ gravity graphs to study the effect of\nquenched connectivity disorder on the phase transition, which is strongly first\norder on regular lattices. The numerical data provides strong evidence that,\ndue to the quenched randomness, the discontinuous first-order phase transition\nof the pure model is softened to a continuous transition.",
        "positive": "Excited B mesons from the lattice: We determine the energies of the excited states of a heavy-light meson\n$Q\\bar{q}$, with a static heavy quark and light quark with mass approximately\nthat of the strange quark from both quenched lattices and with dynamical\nfermions. We are able to explore the energies of orbital excitations up to L=3,\nthe spin-orbit splitting up to L=2 and the first radial excitation. These $b\n\\bar{s}$ mesons will be very narrow if their mass is less than 5775 MeV -- the\n$BK$ threshold. We investigate this in detail and present evidence that the\nscalar meson (L=1) will be very narrow and that as many as 6 $b \\bar{s}$\nexcited states will have energies close to the $BK$ threshold and should also\nbe relatively narrow."
    },
    {
        "anchor": "Some peculiarities of transition from discrete to continuum Fourier\n  series in lattice theories: Transition from discrete to continuous Fourier series is studied for the\nfunctions becoming singular in the transition. Conditions are specified when\nsumming replacement by integration is inadmissible.",
        "positive": "Including Tetraquark Operators in the Low-Lying Scalar Meson Sectors in\n  Lattice QCD: Lattice QCD allows us to probe the low-lying hadron spectrum in finite-volume\nusing a basis of single- and multi-hadron interpolating operators. Here we\nexamine the effect of including tetraquark operators on the spectrum in the\nscalar meson sectors containing the $K_0^*(700)$ ($\\kappa$) and the $a_0(980)$\nin $N_f = 2 + 1$ QCD, with $m_\\pi \\approx 230$ MeV. Preliminary results of\nadditional finite-volume states found using tetraquark operators are shown, and\npossible implications of these states are discussed."
    },
    {
        "anchor": "Universal properties of the confining string in the random percolation\n  model: Random percolation can be fully interpreted as a confining pure gauge theory.\nWith numerical high-precision measurements of Polyakov-Polyakov correlators at\nfinite temperature, we could well observe the presence of shape effects due to\nrough fluctuations of the confining string, in complete agreement with the\nuniversality predictions up to the next-to-leading order.",
        "positive": "Mass Relation Between Top and Bottom Quarks: In the framework of the recently proposed electroweak theory on a Planck\nlattice, we are able to solve approximately the lattice Dyson equation for the\nfermion self-energy functions, and obtain the ratio between the masses of the\n$t-$ and $b-$ quarks in terms of the electroweak coupling constants. The\npredicted top mass agrees with recent determinations from electroweak\nobservables."
    },
    {
        "anchor": "Isospin breaking effects due to the up-down mass difference in Lattice\n  QCD: We present a new method to evaluate with high precision isospin breaking\neffects due to the small mass difference between the up and down quarks using\nlattice QCD. Our proposal is applicable in principle to any hadronic observable\nwhich can be computed on the lattice. It is based on the expansion of the\npath-integral in powers of the small parameter md-mu. In this paper, we apply\nthis method to compute the leading isospin breaking effects for several\nphysical quantities of interest: the kaon meson masses, the kaon decay\nconstant, the form factors of semileptonic Kl3 decays and the neutron-proton\nmass splitting.",
        "positive": "Mobility edge in lattice QCD: We determine the location $\\lambda_c$ of the mobility edge in the spectrum of\nthe hermitian Wilson operator on quenched ensembles. We confirm a theoretical\npicture of localization proposed for the Aoki phase diagram. When $\\lambda_c>0$\nwe also determine some key properties of the localized eigenmodes with\neigenvalues $|\\lambda|<\\lambda_c$. Our results lead to simple tests for the\nvalidity of simulations with overlap and domain-wall fermions."
    },
    {
        "anchor": "Smooth interpolation of lattice gauge fields by signal processing\n  methods: We digitally filter the Fourier modes of the link angles of an abelian\nlattice gauge field which produces the Fourier modes of a continuum $A_\\mu(x)$\nthat exactly reproduces the lattice links through their definition as phases of\nfinite parallel transport. The constructed interpolation is smooth\n($C^\\infty$), free from transition functions, and gauge equivariant. After\ndiscussing some properties of this interpolation, we discuss the non-abelian\ngeneralization of the method, arriving for SU(2), at a Cayley parametrization\nof the links in terms of the Fourier modes of $A^c_\\mu(x)$. We then discuss the\nuse of a maximum entropy type method to address gauge invariance in the\nnon-abelian case.",
        "positive": "String Tension from Monopoles in SU(2) Lattice Gauge Theory: The axis for Figure 2 was wrong. It has been fixed and the postscript file\nreplaced (The file was called comp.ps)."
    },
    {
        "anchor": "Series studies of the Potts model. III: The 3-state model on the simple\n  cubic lattice: The finite lattice method of series expansion has been used to extend\nlow-temperature series for the partition function, order parameter and\nsusceptibility of the $3$-state Potts model on the simple cubic lattice to\norder $z^{43}$ and the high-temperature expansion of the partition function to\norder $v^{21}$. We use the numerical data to show that the transition is\nfirst-order, and estimate the latent heat, the discontinuity in the\nmagnetisation, and a number of other critical parameters.",
        "positive": "Testing Topology Conserving Gauge Actions for Lattice QCD: We explore gauge actions for lattice QCD, which are constructed such that the\noccurrence of small plaquette values is strongly suppressed. Such actions\noriginate from the admissibility condition in order to conserve the topological\ncharge. The suppression of small plaquette values is expected to be\nadvantageous for numerical studies in the $\\epsilon$-regime and also for\nsimulations with dynamical quarks. Performing simulations at a lattice spacing\nof about 0.1 fm, we present numerical results for the static potential, the\nphysical scale $r_0$, the stability of the topological charge history, the\ncondition number of the kernel of the overlap operator and the acceptance rate\nagainst the step size in the local HMC algorithm."
    },
    {
        "anchor": "Curved domain-wall fermion and its anomaly inflow: We investigate the effect of $U (1)$ gauge field on lattice fermion systems\nwith a curved domain-wall mass term. In the same way as the conventional flat\ndomain-wall fermion, the chiral edge modes appear localized at the wall, whose\nDirac operator contains the induced gravitational potential as well as the\n$U(1)$ vector potential. In the case of $S^1$ domain-wall fermion on a\ntwo-dimensional flat lattice, we find a competition between the\nAharonov-Bohm(AB) effect and gravitational gap in the Dirac eigenvalue\nspectrum, which leads to anomaly of the time-reversal ($T$) symmetry. Our\nnumerical result shows a good consistency with the Atiyah-Patodi-Singer index\ntheorem on a disk inside the $S^1$ domain-wall, which describes the\ncancellation of the $T$ anomaly between the bulk and edge. When the $U(1)$ flux\nis squeezed inside one plaquette, and the AB phase takes a quantized value\n$\\pi$ mod $2\\pi\\mathbb{Z}$, the anomaly inflow drastically changes: the strong\nflux creates another domain-wall around the flux to make the two zero modes\ncoexist. This phenomenon is also observed in the $S^2$ domain-wall fermion in\nthe presence of a magnetic monopole. We find that the domain-wall creation\naround the monopole microscopically explains the Witten effect.",
        "positive": "Gauge invariant generalization of the 2D chiral Gross-Neveu model: By means of the Lee-Shrock transformation we generalize the 2D Gross-Neveu\n(GN$_2$) model to a U(1) gauge theory with charged fermion and scalar fields in\n2D ($\\chi U \\phi_2$ model). The $\\chi U \\phi_2$ model is equivalent to the\nGN$_2$ model at infinite gauge coupling. We show that the dynamical fermion\nmass generation and asymptotic freedom in the effective four-fermion coupling\npersist also when the gauge coupling decreases. These phenomena are not\ninfluenced by the XY$_2$ model phase transition at weak coupling. This suggests\nthat the $\\chi U \\phi_2$ model is in the same universality class as the GN$_2$\nmodel and thus renormalizable."
    },
    {
        "anchor": "Center vortex influence on the Dirac spectrum: We study the influence of center vortices on the low-lying eigenmodes of the\nDirac operator, in both the overlap and asqtad formulations. For\ncenter-projected configurations, one finds that the low-lying near-zero modes\nare present in the staggered (asqtad) formulation, but not in the overlap and\n\"chirally-improved\" formulations. We argue that this is due to the absence of a\nfield-independent chiral symmetry in the latter formulations, when the Dirac\noperator is evaluated on the very rough configurations generated by center\nprojection. We also confirm and extend the results of Kovalenko et al. [Phys.\nLett. B 648, 383 (2007)], finding strong correlations between center vortex\nlocations, and the scalar density of low-lying Dirac eigenmodes on unprojected\nlattices, in both asqtad and overlap formulations. It is found that the\nlow-lying eigenmodes have their largest concentrations in point-like regions,\nrather than on submanifolds of higher dimensionality.",
        "positive": "Lattice Simulations and Infrared Conformality: We examine several recent lattice-simulation data sets, asking whether they\nare consistent with infrared conformality. We observe, in particular, that for\nan SU(3) gauge theory with 12 Dirac fermions in the fundamental representation,\nrecent simulation data can be described assuming infrared conformality. Lattice\nsimulations include a fermion mass m which is then extrapolated to zero, and we\nnote that this data can be fit by a small-m expansion, allowing a controlled\nextrapolation. We also note that the conformal hypothesis does not work well\nfor two theories that are known or expected to be confining and chirally\nbroken, and that it does work well for another theory expected to be infrared\nconformal."
    },
    {
        "anchor": "Correlations and Binding in 4D Dynamical Triangulation: We study correlations on the euclidean spacetimes generated in Monte Carlo\nsimulations of the model. In the elongated phase, curvature correlations appear\nto fall off like a fractional power. Near the transition to the crumpled phase\nthis power is consistent with 4. We also present improved data of our\ncomputations of the binding energy of test particles.",
        "positive": "Center Projection With and Without Gauge Fixing: We consider projections of SU(2) lattice link variables onto Z(2) center and\nU(1) subgroups, with and without gauge-fixing. It is shown that in the absence\nof gauge-fixing, and up to an additive constant, the static quark potential\nextracted from projected variables agrees exactly with the static quark\npotential taken from the full link variables; this is an extension of recent\narguments by Ambjorn and Greensite, and by Ogilvie. Abelian and center\ndominance is essentially trivial in this case, and seems of no physical\nrelevance. The situation changes drastically upon gauge fixing. In the case of\ncenter projection, there are a series of tests one can carry out, to check if\nvortices identified in the projected configurations are physical objects. All\nthese criteria are satisfied in maximal center gauge, and we show here that\nthey all fail in the absence of gauge fixing. The non-triviality of center\nprojection is due entirely to the maximal center gauge-fixing, which pumps\ninformation about the location of extended physical objects into local Z(2)\nobservables."
    },
    {
        "anchor": "Phase Structure of lattice SU(2)xU_S(1) three-dimensional Gauge Theory: We discuss a phase diagram for a relativistic SU(2) x U_{S}(1) lattice gauge\ntheory, with emphasis on the formation of a parity-invariant chiral condensate,\nin the case when the $U_{S}(1)$ field is infinitely coupled, and the SU(2)\nfield is moved away from infinite coupling by means of a strong-coupling\nexpansion. We provide analytical arguments on the existence of (and partially\nderive) a critical line in coupling space, separating the phase of broken SU(2)\nsymmetry from that where the symmetry is unbroken. We review uncoventional\n(Kosterlitz-Thouless type) superconducting properties of the model, upon\ncoupling it to external electromagnetic potentials. We discuss the r\\^ole of\ninstantons of the unbroken subgroup U(1) of SU(2), in eventually destroying\nsuperconductivity under certain circumstances. The model may have applications\nto the theory of high-temperature superconductivity. In particular, we argue\nthat in the regime of the couplings leading to the broken SU(2) phase, the\nmodel may provide an explanation on the appearance of a pseudo-gap phase, lying\nbetween the antiferromagnetic and the superconducting phases. In such a phase,\na fermion mass gap appears in the theory, but there is no phase coherence, due\nto the Kosterlitz-Thouless mode of symmetry breaking. The absence of\nsuperconductivity in this phase is attributed to non-perturbative effects\n(instantons) of the subgroup U(1) of SU(2).",
        "positive": "Lattice QCD static potentials of the meson-meson and tetraquark systems\n  computed with both quenched and full QCD: We revisit the static potential for the $Q Q \\bar Q \\bar Q$ system using\nSU(3) lattice simulations, studying both the colour singlets groundstate and\nfirst excited state. We consider geometries where the two static quarks and the\ntwo anti-quarks are at the corners of rectangles of different sizes. We analyse\nthe transition between a tetraquark system and a two meson system with a two by\ntwo correlator matrix. We compare the potentials computed with quenched QCD and\nwith dynamical quarks. We also compare our simulations with the results of\nprevious studies and analyze quantitatively fits of our results with anzatse\ninspired in the string flip-flop model and in its possible colour excitations."
    },
    {
        "anchor": "More about orbitally excited hadrons from lattice QCD: This is a second paper describing the calculation of spectroscopy for\norbitally excited states from lattice simulations of Quantum Chromodynamics.\nNew features include higher statistics for P-wave systems and first results for\nthe spectroscopy of D-wave mesons and baryons, for relatively heavy quark\nmasses. We parameterize the Coulomb gauge wave functions for P-wave and D-wave\nsystems and compare them to those of their corresponding S-wave states.",
        "positive": "Imaginary chemical potential and finite fermion density on the lattice: Standard lattice fermion algorithms run into the well-known sign problem at\nreal chemical potential. In this paper we investigate the possibility of using\nimaginary chemical potential, and argue that it has advantages over other\nmethods, particularly for probing the physics at finite temperature as well as\ndensity. As a feasibility study, we present numerical results for the partition\nfunction of the two-dimensional Hubbard model with imaginary chemical\npotential.\n  We also note that systems with a net imbalance of isospin may be simulated\nusing a real chemical potential that couples to I_3 without suffering from the\nsign problem."
    },
    {
        "anchor": "Lattice QCD at the physical point: Simulation and analysis details: We give details of our precise determination of the light quark masses\nm_{ud}=(m_u+m_d)/2 and m_s in 2+1 flavor QCD, with simulated pion masses down\nto 120 MeV, at five lattice spacings, and in large volumes. The details concern\nthe action and algorithm employed, the HMC force with HEX smeared clover\nfermions, the choice of the scale setting procedure and of the input masses.\nAfter an overview of the simulation parameters, extensive checks of algorithmic\nstability, autocorrelation and (practical) ergodicity are reported. To\ncorroborate the good scaling properties of our action, explicit tests of the\nscaling of hadron masses in N_f=3 QCD are carried out. Details of how we\ncontrol finite volume effects through dedicated finite volume scaling runs are\nreported. To check consistency with SU(2) Chiral Perturbation Theory the\nbehavior of M_\\pi^2/m_{ud} and F_\\pi as a function of m_{ud} is investigated.\nDetails of how we use the RI/MOM procedure with a separate continuum limit of\nthe running of the scalar density R_S(\\mu,\\mu') are given. This procedure is\nshown to reproduce the known value of r_0m_s in quenched QCD. Input from\ndispersion theory is used to split our value of m_{ud} into separate values of\nm_u and m_d. Finally, our procedure to quantify both systematic and statistical\nuncertainties is discussed.",
        "positive": "Non-uniform measure in 4d simplicial quantum gravity: Four-dimensional euclidean quantum gravity has been studied as a discrete\nmodel based on dynamical triangulations by Ambjorn and Jurkiewicz and by\nAgishtein and Migdal. We discuss a particular implementation of a Monte Carlo\nsimulation of simplicial quantum gravity. As an application we introduce a\nnon-uniform measure and examine its effect on simple aspects of the\nmathematical geometry. We find that the transition region from the hot to the\ncold phase is shifted and that the criticality of the transition changes."
    },
    {
        "anchor": "Screening without screening: baryon energy at high baryon density: We compute the Coulomb interaction energy of dense sets of static quarks in a\ncompact volume (much smaller than the lattice volume) containing one quark per\nlattice site. The quark color charges are combined into either a set of\nthree-quark nucleon states, or into a non-factorizable \"one big hadron\" state.\nIn both cases we find that the energy per quark is roughly constant as the\nvolume of quarks increases. A surprise is that if we construct the nucleon\nstates from sets of three quarks chosen at random in the volume, then the\nenergy per quark remains roughly constant, even as the average distance between\nquarks in a nucleon state grows as the volume increases. This energy dependence\nof a nucleon in a dense medium is at odds with the behavior of an isolated\nnucleon as quark separation increases, and for static quarks it is not easily\nexplicable in terms of some version of Debye screening.",
        "positive": "BRST-Symmetry Breaking and Bose-Ghost Propagator in Lattice Minimal\n  Landau Gauge: The Bose-ghost propagator has been proposed as a carrier of the confining\nforce in Yang-Mills theories in minimal Landau gauge. We present the first\nnumerical evaluation of this propagator, using lattice simulations for the\nSU(2) gauge group in the scaling region. Our data are well described by a\nsimple fitting function, which is compatible with an infrared-enhanced\nBose-ghost propagator. This function can also be related to a massive gluon\npropagator in combination with an infrared-free (Faddeev-Popov) ghost\npropagator. Since the Bose-ghost propagator can be written as the vacuum\nexpectation value of a BRST-exact quantity and should therefore vanish in a\nBRST-invariant theory, our results provide the first numerical manifestation of\nBRST-symmetry breaking due to restriction of gauge-configuration space to the\nGribov region."
    },
    {
        "anchor": "A test of first order scaling in Nf=2 QCD: We complete our analysis of Nf=2 QCD based on the lattice staggered fermion\nformulation. Using a series of Monte Carlo simulations at fixed (amq*Ls^yh) one\nis able to test the universality class with given critical exponent yh. This\nstrategy has been used to test the O(4) universality class and it has been\npresented at the previous Lattice conferences. No agreement was found with\nsimulations in the mass range amq=[0.01335,0.15] using lattices with Ls=16 up\nto 32 and Lt=4. With the same strategy, we now investigate the possibility of a\nfirst order transition using a new set of Monte Carlo data corresponding to\nyh=3 in the same mass and volume range as the one used for O(4). A substantial\nagreement is observed both in the specific heat scaling and in the scaling of\nthe chiral condensate, while the chiral susceptibilities still presents visible\ndeviation from scaling in the mass range explored.",
        "positive": "Reconstructing lattice QCD spectral functions with stochastic pole\n  expansion and Nevanlinna analytic continuation: The reconstruction of spectral functions from Euclidean correlation functions\nis a well-known, yet ill-posed inverse problem in the fields of many-body and\nhigh-energy physics. In this paper, we present a comprehensive investigation of\ntwo recently developed analytic continuation methods, namely stochastic pole\nexpansion and Nevanlinna analytic continuation, for extracting spectral\nfunctions from mock lattice QCD data. We examine a range of Euclidean\ncorrelation functions generated by representative models, including the\nBreit-Wigner model, the Gaussian mixture model, the resonance-continuum model,\nand the bottomonium model. Our findings demonstrate that the stochastic pole\nexpansion method, when combined with the constrained sampling algorithm and the\nself-adaptive sampling algorithm, successfully recovers the essential features\nof the spectral functions and exhibits excellent resilience to noise of input\ndata. In contrast, the Nevanlinna analytic continuation method suffers from\nnumerical instability, often resulting in the emergence of spurious peaks and\nsignificant oscillations in the high-energy regions of the spectral functions,\neven with the application of the Hardy basis function optimization algorithm."
    },
    {
        "anchor": "Hadron masses and decay constants in quenched QCD: We present results for the mass spectrum and decay constants using\nnon-perturbatively O(a) improved Wilson fermions. Three values of $\\beta$ and\n30 different quark masses are used to obtain the chiral and continuum limits.\nSpecial emphasis will be given to the question of taking the chiral limit and\nthe existence of non-analytic behavior predicted by quenched chiral\nperturbation theory.",
        "positive": "The dyonic picture of topological objects in the deconfined phase: In the deconfinement phase of quenched SU(2) Yang-Mills theory the spectrum\nand localization properties of the eigenmodes of the overlap Dirac operator\nwith antiperiodic boundary conditions are strongly dependent on the sign of the\naverage Polyakov loop, $<L>$. For $<L> > 0$ a gap appears with only few, highly\nlocalized topological zero and near-zero modes separated from the rest of the\nspectrum. Instead of a gap, for $<L> < 0$ a high spectral density of relatively\ndelocalized near-zero modes is observed. In an ensemble of positive $<L>$, the\nsame difference of the spectrum appears under a change of fermionic boundary\nconditions. We argue that this effect and other properties of near-zero modes\ncan be explained through the asymmetric properties and the different abundance\nof dyons and antidyons -- topological objects also known to appear, however in\na symmetric form, in the confinement phase at $T < T_c$ as constituents of\ncalorons with maximally nontrivial holonomy."
    },
    {
        "anchor": "Chiral Symmetry Breaking in Abelian-Projected SU(2) Lattice Gauge Theory: Chiral symmetry breaking parameters are calculated in quenched SU(2) gauge\ntheory and with Abelian gauge fields projected in maximal Abelian gauge and in\nfield strength gauge. Maximal Abelian gauge projected fields lead to chiral\ncondensate values which are quite similar to those of the full nonabelian\ntheory. Pseudoscalar and vector meson correlators are calculated and found to\nbe reproduced by the use of maximal Abelian gauge fields for small quark\nmasses. In field-strength gauge, Abelian-projected fields give a chiral\ncondensate which closely resembles the results of strongly coupled ($\\beta<1$)\ngauge theory: the chiral condensate is insensitive to $\\beta$ and quark mass\nand hence violates scaling badly.",
        "positive": "Bound states in the 3d Ising model and implications for QCD at finite\n  temperature and density: We study the spectrum of bound states of the three dimensional Ising model in\nthe (h,beta) plane near the critical point. We show the existence of an\nunbinding line, defined as the boundary of the region where bound states exist.\nNumerical evidence suggests that this line coincides with the beta=beta_c axis.\nWhen the 3D Ising model is considered as an effective description of hot QCD at\nfinite density, we conjecture the correspondence between the unbinding line and\nthe line that separates the quark-gluon plasma phase from the superconducting\nphase. The bound states of the Ising model are conjectured to correspond to the\ndiquarks of the latter phase of QCD."
    },
    {
        "anchor": "Weak transition matrix elements from finite-volume correlation functions: The two-body decay rate of a weakly decaying particle (such as the kaon) is\nshown to be proportional to the square of a well-defined transition matrix\nelement in finite volume. Contrary to the physical amplitude, the latter can be\nextracted from finite-volume correlation functions in euclidean space without\nanalytic continuation. The K -> pi pi transitions and other non-leptonic decays\nthus become accessible to established numerical techniques in lattice QCD.",
        "positive": "Di-Quarks and Tri-Quarks on the Lattice: The distribution of gluon fields in hadrons is of fundamental interest in\nQCD. Using lattice QCD we have observed the formation of gluon flux tubes\nwithin tri-quark (baryon) systems for a wide variety of spatial distributions\nof the color sources. In particular we have investigated configurations where\ntwo of the quarks are close together and the third quark is some distance away,\nwhich approximates a quark plus diquark string. We find that the string tension\nof the quark-diquark string is the same as that of the quark-antiquark string\non the same lattice. We also compare the longitudinal and transverse profiles\nof the gluon flux tubes for both sets of strings, and find them to be of\nsimilar radii and to have similar vacuum suppression."
    },
    {
        "anchor": "Extension of the Nielsen-Ninomiya theorem: The index theorem is employed to extend the no-go theorem for lattice chiral\nDirac fermions to translation non-invariant and non-local formulations.",
        "positive": "Functional Forms for Lattice Correlators at Small Times: The analytic form of the lattice quark propagator is used to derive the\nfunctional form for short distance mesonic correlators. These are then used to\ncalculate ``Continuum Model'' Ansatze which comprise of a pole, representing\nthe ground state, plus a contribution for the excited states, coming from the\nshort distance behaviour. These are compared to Monte Carlo data."
    },
    {
        "anchor": "Spectral reconstruction in NRQCD via the Backus-Gilbert method: We present progress results from the FASTSUM collaboration's programme to\ndetermine the spectrum of the bottomonium system as a function of temperature\nusing a variety of approaches. In this contribution, the Backus Gilbert method\nis used to reconstruct spectral functions from NRQCD meson correlator data from\nFASTSUM's anisotropic ensembles at nonzero temperature. We focus in particular\non the resolving power of the method, providing a demonstration of how the\nunderlying resolution functions can be probed by exploiting the Laplacian\nnature of the NRQCD kernel. We conclude with estimates of the bottomonium\nground state mass and widths at nonzero temperature.",
        "positive": "Meson Screening Masses at high Temperature in quenched QCD with improved\n  Wilson Quarks: We report on a lattice investigation of improved quenched Wilson fermions\nabove and below the confinement-deconfinement phase transition. Results on\nmeson screening masses as well as spatial wave functions are presented.\nMoreover, the meson dispersion relation is studied. Below the critical\ntemperature we do not observe any significant temperature effect while above\n$T_c$ the data are consistent with a leading free quark behavior."
    },
    {
        "anchor": "The light Roberge-Weiss tricritical endpoint at imaginary isospin and\n  baryon chemical potential: Imaginary chemical potentials serve as a useful tool to constrain the QCD\nphase diagram and to gain insight into the thermodynamics of strongly\ninteracting matter. In this study, we report on the first determination of the\nphase diagram for arbitrary imaginary baryon and isospin chemical potentials at\nhigh temperature using one-loop perturbation theory, revealing a nontrivial\nstructure of Roberge-Weiss (RW) phase transitions in this plane. Subsequently,\nthis system is simulated numerically with $N_{\\rm f}=2$ unimproved staggered\nquarks on $N_{\\tau}=4$ lattices at a range of temperatures at one of the RW\nphase transitions. We establish a lower bound for the light quark mass, where\nthe first-order transition line terminates in a tricritical point. It is found\nthat this tricritical mass is increased as compared to the case of purely\nbaryonic imaginary chemical potentials, indicating that our setup is more\nadvantageous for identifying critical behavior towards the chiral limit.\nFinally, the dynamics of local Polyakov loop clusters is also studied in\nconjuction with the RW phase transition.",
        "positive": "Monte Carlo studies on the expanding behavior of the early universe in\n  the Lorentzian type IIB matrix model: The type IIB matrix model is a conjectured nonperturbative formulation of\nsuperstring theory. Recently the Lorentzian version of the model has been\nstudied by Monte Carlo simulation, and it has been shown that only three out of\nnine spatial directions start to expand after a critical time. We extend this\nwork by investigating the expanding behavior for much longer time. We find that\nthe 3d space expands exponentially for some period of time, which may be\ninterpreted as inflation. We also simulate a simplified model, which is\nexpected to capture some qualitative features of the original model at much\nlater times. We observe that the exponential expansion eventually changes into\na power-law t^(1/2) behavior, which agrees with the expanding behavior of the\nFriedmann-Robertson-Walker (FRW) universe in the radiation dominated era."
    },
    {
        "anchor": "Polyakov loop effects on the phase diagram in strong-coupling lattice\n  QCD: We investigate the Polyakov loop effects on the QCD phase diagram by using\nthe strong-coupling (1/g^2) expansion of the lattice QCD (SC-LQCD) with one\nspecies of unrooted staggered quark, including O}(1/g^4) effects. We take\naccount of the effects of Polyakov loop fluctuations in Weiss mean-field\napproximation (MFA), and compare the results with those in the Haar-measure MFA\n(no fluctuation from the mean-field). The Polyakov loops strongly suppress the\nchiral transition temperature in the second-order/crossover region at small\nchemical potential, while they give a minor modification of the first-order\nphase boundary at larger chemical potential. The Polyakov loops also account\nfor a drastic increase of the interaction measure near the chiral phase\ntransition. The chiral and Polyakov loop susceptibilities have their peaks\nclose to each other in the second-order/crossover region. In particular in\nWeiss MFA, there is no indication of the separated deconfinement transition\nboundary from the chiral phase boundary at any chemical potential. We discuss\nthe interplay between the chiral and deconfinement dynamics via the bare quark\nmass dependence of susceptibilities.",
        "positive": "New descriptions of lattice SU(N) Yang-Mills theory towards quark\n  confinement: We give new descriptions of lattice SU(N) Yang-Mills theory in terms of new\nlattice variables. The validity of such descriptions has already been\ndemonstrated in the SU(2) Yang-Mills theory by our previous works from the\nviewpoint of defining and extracting topological degrees of freedom such as\ngauge-invariant magnetic monopoles and vortices which play the dominant role in\nquark confinement. In particular, we have found that the SU(3) lattice\nYang-Mills theory has two possible options, maximal and minimal: The existence\nof the minimal option has been overlooked so far, while the maximal option\nreproduces the conventional SU(3) Cho-Faddeev-Niemi-Shabanov decomposition in\nthe naive continuum limit. The new description gives an important framework for\nunderstanding the mechanism of quark confinement based on the dual\nsuperconductivity."
    },
    {
        "anchor": "The Aoki phase revisited: In order to elucidate the vacuum structure of the Aoki phase, we carried out\na numerical investigation of QCD with two flavours of Wilson fermions, within\nthe p.d.f. framework and in the absence of external sources. The simulations\nperformed at V = 44 suggest a rich vacuum structure, where the observable\n$i\\bar\\psi\\gamma_5\\psi$ is allowed to take non-zero values of the same order of\nmagnitude than the order parameter of the Aoki phase\n$i\\bar\\psi\\gamma_5\\tau_3\\psi$. However, the simulation at higher volumes V =\n6^4 suffers from large statistical errors.",
        "positive": "Towards the continuum limit with improved Wilson fermions employing open\n  boundary conditions: We present selected results obtained by RQCD from simulations of $N_f=2+1$\nflavours of non-perturbatively $\\mathcal{O}(a)$ improved Wilson fermions,\nemploying open boundary conditions in time. The ensembles were created within\nthe CLS (Coordinated Lattice Simulations) effort at five different values of\nthe lattice spacing, ranging from 0.085fm down to below 0.04fm. Many quark mass\ncombinations were realized, in particular along lines where the sum of the bare\nquark masses was kept fixed as well as trajectories of an approximately\nphysical renormalized strange quark mass. Several key observables, including\nmeson and baryon masses and the axial charge of the nucleon have been computed,\nand preliminary results are presented here. In some cases an accurate and\ncontrolled extrapolation to the continuum limit has become possible."
    },
    {
        "anchor": "RG decimation-based approach to confinement and computation on coarser\n  lattices: A systematic procedure is presented for connecting short to long scales in\nLGT. Approximate decimations are used which can provide both upper and lower\nbounds on the partition function. Its exact value is then obtained by\ninterpolation between the bounds. By iterating the procedure representations of\nthe partition function as well as other physical quantities can be obtained on\nprogressively coarser lattices. For SU(2) IR flow into the confining strong\ncoupling regime results for any initial $\\beta$.",
        "positive": "Where is the confining string in random percolation: The percolating phase of whatever random percolation process resembles the\nconfining vacuum of a gauge theory in most respects, with a string tension\nhaving a well-behaved continuum limit, a non trivial glueball spectrum and a\ndeconfinement transition at a well determined temperature T_c. Simple numerical\nexperiments reveal an underlying, strongly fluctuating, confining string, with\nan internal vortex structure formed by a core trapping inside a Coulomb-like\nphase composed by the vacuum at the percolation threshold. The width of the\ncore almost coincides with 1/T_c and it turns out to be separated form the\nconfining vacuum by a domain wall of definite thickness."
    },
    {
        "anchor": "Monopole density around static color sources: We analyze the vacuum structure with respect to magnetic monopoles of\nquenched QCD in the presence of static color sources. Distributions of the\nmonopole density around static quarks and mesons are computed in both phases of\nQCD. We observe a suppression of the monopole density in the vicinity of\nexternal sources. In the confinement phase the density of color magnetic\nmonopoles is reduced along the flux tube between a static quark-antiquark pair.",
        "positive": "TUNING TO $N=2$ SUPERSYMMETRY IN THE SU(2) ADJOINT HIGGS-YUKAWA MODEL: The $N=2$ supersymmetric continuum limit is investigated in the SU(2) adjoint\nHiggs-Yukawa model using lattice perturbation theory. In the one-loop\nrenormalization group equations a non-trivial infrared fixed point of coupling\nratios is found. The phase structure at weak couplings is determined by a\nnumerical study of the one-loop effective potential."
    },
    {
        "anchor": "Critical exponents and abelian dominance in $SU(2)$ QCD: The critical properties of the abelian Polyakov loop and the Polyakov loop in\nterms of Dirac string are studied in finite temperature abelian projected\n$SU(2)$ QCD. We evaluate the critical point and the critical exponents from\neach Polyakov loop in the maximally abelian gauge using the finite-size scaling\nanalysis. Abelian dominance in this case is proved quantitatively. The critical\npoint of each abelian Polyakov loop is equal to that of the non-abelian\nPolyakov loop within the statistical errors. Also, the critical exponents are\nin good agreement with those from non-abelian Polyakov loops.",
        "positive": "Gauge-equivariant neural networks as preconditioners in lattice QCD: We demonstrate that a state-of-the art multi-grid preconditioner can be\nlearned efficiently by gauge-equivariant neural networks. We show that the\nmodels require minimal re-training on different gauge configurations of the\nsame gauge ensemble and to a large extent remain efficient under modest\nmodifications of ensemble parameters. We also demonstrate that important\nparadigms such as communication avoidance are straightforward to implement in\nthis framework."
    },
    {
        "anchor": "Continuous renormalization group $\u03b2$ function from lattice\n  simulations: We present a real-space renormalization group transformation with continuous\nscale change to calculate the continuous renormalization group $\\beta$ function\nin non-perturbative lattice simulations. Our method is motivated by the\nconnection between Wilsonian renormalization group and the gradient flow\ntransformation. It does not rely on the perturbative definition of the\nrenormalized coupling and is also valid at non-perturbative fixed points.\nAlthough our method requires an additional extrapolation compared to\ntraditional step scaling calculations, it has several advantages which\ncompensates for this extra step even when applied in the vicinity of the\nperturbative fixed point. We illustrate our approach by calculating the $\\beta$\nfunction of 2-flavor QCD and show that lattice predictions from individual\nlattice ensembles, even without the required continuum and finite volume\nextrapolations, can be very close to the result of the full analysis. Thus our\nmethod provides a non-perturbative framework and intuitive understanding into\nthe structure of strongly coupled systems, in addition to being complementary\nto existing lattice determinations.",
        "positive": "Classical Simulation of Quantum Fields II: We consider the classical time evolution of a real scalar field in 2\ndimensional Minkowski space with a $\\lambda \\phi^4$ interaction. We compute the\nspatial and temporal two-point correlation functions and extract the\nrenormalized mass of the interacting theory. We find our results are consistent\nwith the one- and two-loop quantum computation. We also perform Monte Carlo\nsimulations of the quantum theory and conclude that the classical scheme is\nable to produce more accurate results with a fraction of the CPU time."
    },
    {
        "anchor": "Hadron Spectroscopy with Dynamical Chirally Improved Fermions: We simulate two dynamical, mass degenerate light quarks on 16^3x32 lattices\nwith a spatial extent of 2.4 fm using the Chirally Improved Dirac operator. The\nsimulation method, the implementation of the action and signals of\nequilibration are discussed in detail. Based on the eigenvalues of the Dirac\noperator we discuss some qualitative features of our approach. Results for\nground state masses of pseudoscalar and vector mesons as well as for the\nnucleon and delta baryons are presented.",
        "positive": "Ghost condensation on the lattice: We perform a numerical study of ghost condensation -- in the so-called\nOverhauser channel -- for SU(2) lattice gauge theory in minimal Landau gauge.\nThe off-diagonal components of the momentum-space ghost propagator G^{cd}(p)\nare evaluated for lattice volumes V = 8^4, 12^4, 16^4, 20^4, 24^4 and for three\nvalues of the lattice coupling: \\beta = 2.2, 2.3, 2.4. Our data show that the\nquantity \\phi^b(p) = \\epsilon^{bcd} G^{cd}(p) / 2 is zero within error bars,\nbeing characterized by very large statistical fluctuations. On the contrary,\n|\\phi^b(p)| has relatively small error bars and behaves at small momenta as\nL^{-2} p^{-z}, where L is the lattice side in physical units and z \\approx 4.\nWe argue that the large fluctuations for \\phi^b(p) come from spontaneous\nbreaking of a global symmetry and are associated with ghost condensation. It\nmay thus be necessary (in numerical simulations at finite volume) to consider\n|\\phi^b(p)| instead of \\phi^b(p), to avoid a null average due to tunneling\nbetween different broken vacua. Also, we show that \\phi^b(p) is proportional to\nthe Fourier-transformed gluon field components {\\widetilde A}_{\\mu}^b(q). This\nexplains the L^{-2} dependence of |\\phi^b(p)|, as induced by the behavior of |\n{\\widetilde A}_{\\mu}^b(q) |. We fit our data for |\\phi^b(p)| to the theoretical\nprediction (r / L^2 + v) / (p^4 + v^2), obtaining for the ghost condensate v an\nupper bound of about 0.058 GeV^2. In order to check if v is nonzero in the\ncontinuum limit, one probably needs numerical simulations at much larger\nphysical volumes than the ones we consider. As a by-product of our analysis, we\nperform a careful study of the color structure of the inverse Faddeev-Popov\nmatrix in momentum space."
    },
    {
        "anchor": "Lattice QCD evaluation of the Compton amplitude employing the\n  Feynman-Hellmann theorem: The forward Compton amplitude describes the process of virtual photon\nscattering from a hadron and provides an essential ingredient for the\nunderstanding of hadron structure. As a physical amplitude, the Compton tensor\nnaturally includes all target mass corrections and higher twist effects at a\nfixed virtuality, $Q^2$. By making use of the second-order Feynman-Hellmann\ntheorem, the nucleon Compton tensor is calculated in lattice QCD at an\nunphysical quark mass across a range of photon momenta $3 \\lesssim Q^2 \\lesssim\n7$ GeV$^2$. This allows for the $Q^2$ dependence of the low moments of the\nnucleon structure functions to be studied in a lattice calculation for the\nfirst time. The results demonstrate that a systematic investigation of power\ncorrections and the approach to parton asymptotics is now within reach.",
        "positive": "Scaled Affine Quantization of $\\varphi^{12}_3$ is Nontrivial: We prove through Monte Carlo analysis that the covariant euclidean scalar\nfield theory, $\\varphi^r_n$, where $r$ denotes the power of the interaction\nterm and $n = s + 1$ where $s$ is the spatial dimension and $1$ adds imaginary\ntime, such that $r = 12, n = 3$ can be acceptably quantized using scaled affine\nquantization and the resulting theory is nontrivial, unlike what happens using\ncanonical quantization when the system is plagued by asymptotic freedom."
    },
    {
        "anchor": "Study of $I=0$ bottomonium bound states and resonances based on lattice\n  QCD static potentials: We investigate $I = 0$ bottomonium bound states and resonances in S, P, D and\nF waves using lattice QCD static-static-light-light potentials. We consider\nfive coupled channels, one confined quarkonium and four open\n$B^{(*)}\\bar{B}^{(*)}$ and $B^{(*)}_s\\bar{B}^{(*)}_s$ meson-meson channels and\nuse the Born-Oppenheimer approximation and the emergent wave method to compute\npoles of the T matrix. We discuss results for masses and decay widths and\ncompare them to existing experimental results. Moreover, we determine the\nquarkonium and meson-meson composition of these states to clarify, whether they\nare ordinary quarkonium or should rather be interpreted as tetraquarks.",
        "positive": "Higgsing Gauge Symmetries with Reduced Staggered Fermions: We show how a strongly coupled lattice theory consisting of just fermions and\ngauge fields can exhibit a dynamical Higgs mechanism through the formation of a\ngauge invariant four fermion condensate. Furthermore, we argue that the\nresultant lattice Higgs phase may survive into the continuum limit."
    },
    {
        "anchor": "Quantum chromodynamics with various number of flavors: The phase structure of QCD with various number of flavors is studied for\nWilson quarks. For the case of $N_F=3$ we find that the finite temperature\ndeconfining transition is of first order in the chiral limit on an $N_t=4$\nlattice. Together with our previous results that the deconfining transition in\nthe chiral limit is continuous for $N_F=2$ and is first order for $N_F=6$, the\norder of the transition is found to be consistent with a prediction of\nuniversality. The case of $SU(2)$ QCD is also studied in the strong coupling\nlimit and the phase structure is found to be quite similar to the case of\n$SU(3)$: There exists a critical number of flavors $N_F^*$ and for $N_F \\geq\nN_F^*$ the confinement is broken even in the strong coupling limit for light\nquarks. $N_F^*=3$ corresponding to 7 for $SU(3)$.",
        "positive": "Lattice Monte Carlo calculations for unitary fermions in a harmonic trap: We present a new lattice Monte Carlo approach developed for studying large\nnumbers of strongly interacting nonrelativistic fermions, and apply it to a\ndilute gas of unitary fermions confined to a harmonic trap. Our lattice action\nis highly improved, with sources of discretization and finite volume errors\nsystematically removed; we are able to demonstrate the expected volume scaling\nof energy levels of two and three untrapped fermions, and to reproduce the high\nprecision calculations published previously for the ground state energies for N\n= 3 unitary fermions in a box (to within our 0.3% uncertainty), and for N = 3,\n. . ., 6 unitary fermions in a harmonic trap (to within our ~ 1% uncertainty).\nWe use this action to determine the ground state energies of up to 70\nunpolarized fermions trapped in a harmonic potential on a lattice as large as\n64^3 x 72; our approach avoids the use of importance sampling or calculation of\na fermion determinant and employs a novel statistical method for estimating\nobservables, allowing us to generate ensembles as large as 10^8 while requiring\nonly relatively modest computational resources."
    },
    {
        "anchor": "Performance of the Cray T3D and Emerging Architectures on Canopy QCD\n  Applications: The Cray T3D, an MIMD system with NUMA shared memory capabilities and in\nprinciple very low communications latency, can support the Canopy framework for\ngrid-oriented applications. CANOPY has been ported to the T3D, with the intent\nof making it available to a spectrum of users. The performance of the T3D\nrunning Canopy has been benchmarked on five QCD applications extensively run on\nACPMAPS at Fermilab, requiring a variety of data access patterns. The net\nperformance and scaling behavior reveals an efficiency relative to peak Gflops\nalmost identical to that achieved on ACPMAPS. Detailed studies of the major\nfactors impacting performance are presented. Generalizations applying this\nanalysis to the newly emerging crop of commercial systems reveal where their\nlimitations will lie. On these applications, efficiencies of above 25\\% are not\nto be expected; eliminating overheads due to Canopy will improve matters, but\nby less than a factor of two.",
        "positive": "Calorons, instantons and constituent monopoles in SU(3) lattice gauge\n  theory: We analyze the zero-modes of the Dirac operator in quenched SU(3) gauge\nconfigurations at non-zero temperature and compare periodic and anti-periodic\ntemporal boundary conditions for the fermions. It is demonstrated that for the\ndifferent boundary conditions often the modes are localized at different\nspace-time points and have different sizes. Our observations are consistent\nwith patterns expected for Kraan - van Baal solutions of the classical\nYang-Mills equations. These solutions consist of constituent monopoles and the\nzero-modes are localized on different constituents for different boundary\nconditions. Our findings indicate that the excitations of the QCD vacuum are\nmore structured than simple instanton-like lumps."
    },
    {
        "anchor": "The three flavour chiral phase transition with an improved quark and\n  gluon action in lattice QCD: The finite-temperature chiral phase transition is investigated for three\nflavours of staggered quarks on a lattice of temporal extent N_t=4. In the\nsimulation we use an improved fermion action which reduces rotational symmetry\nbreaking of the quark propagator (p4-action), include fat-links to improve the\nflavour symmetry and use the tree level improved (1,2) gluon action. We study\nthe nature of the phase transition for quark masses of ma=0.025, ma=0.05 and\nma=0.1 on lattices with spatial sizes of 8^3 and 16^3.",
        "positive": "Non-perturbative improvement of stout-smeared three flavour clover\n  fermions: We discuss a 3-flavour lattice QCD action with clover improvement in which\nthe fermion matrix has single level stout smearing for the hopping terms\ntogether with unsmeared links for the clover term. With the (tree-level)\nSymanzik improved gluon action this constitutes the Stout Link Non-perturbative\nClover or SLiNC action. To cancel O(a) terms the clover term coefficient has to\nbe tuned. We present here results of a non-perturbative determination of this\ncoefficient using the Schroedinger functional and as a by-product a\ndetermination of the critical hopping parameter. Comparisons of the results are\nmade with lowest order perturbation theory."
    },
    {
        "anchor": "On the Viability of Lattice Perturbation Theory: In this paper we show that the apparent failure of QCD lattice perturbation\ntheory to account for Monte Carlo measurements of perturbative quantities\nresults from choosing the bare lattice coupling constant as the expansion\nparameter. Using instead ``renormalized'' coupling constants defined in terms\nof physical quantities, like the heavy-quark potential, greatly enhances the\npredictive power of lattice perturbation theory. The quality of these\npredictions is further enhanced by a method for automatically determining the\ncoupling-constant scale most appropriate to a particular quantity. We present a\nmean-field analysis that explains the large renormalizations relating lattice\nquantities, like the coupling constant, to their continuum analogues. This\nsuggests a new prescription for designing lattice operators that are more\ncontinuum-like than conventional operators. Finally, we provide evidence that\nthe scaling of physical quantities is asymptotic or perturbative already at\n$\\beta$'s as low as 5.7, provided the evolution from scale to scale is analyzed\nusing renormalized perturbation theory. This result indicates that reliable\nsimulations of (quenched) QCD are possible at these same low $\\beta$'s.",
        "positive": "$|V_{ub}|$ determination in lattice QCD: The 2012 PDG reports a tension at the level of $3 \\sigma$ between two\nexclusive determinations of $|V_{ub}|$. They are obtained by combining the\nexperimental branching ratios of $B \\to \\tau \\nu$ and $B \\to \\pi l \\nu$\n(respectively) with a theoretical computation of the hadronic matrix elements\n$\\fB$ and the $B \\to \\pi$ form factor $f_+(q^2)$. To understand the tension,\nimproved precision and a careful analysis of the systematics involved are\nnecessary. We report the results of the ALPHA collaboration for $\\fB$ from the\nlattice with 2 flavors of $O(a)$ improved Wilson fermions. We employ HQET,\nincluding $1/m_b$ corrections, with pion masses ranging down to $\\approx$ 190\nMeV. Renormalization and matching were performed non-perturbatively, and three\nlattice spacings reaching $a^{-1}\\approx 4.1$ GeV are used in the continuum\nextrapolation. We also present progress towards a computation of $f_+(q^2)$, to\ndirectly compare two independent exclusive determinations of $|V_{ub}|$ with\neach other and with inclusive determinations. Additionally, we report on\npreliminary results for $\\fBq{s}$, needed for the analysis of $B_s \\to\n\\mu^+\\mu^-$.}"
    },
    {
        "anchor": "Chiral condensate in nf=2 QCD from the Banks-Casher relation: Exploiting the Banks-Casher relation, we present a direct determination of\nthe chiral condensate in two-flavor QCD, computing the mode number of the\nO(a)-improved Wilson-Dirac operator below various cutoffs. We make use of\nCLS-configurations with three different lattice spacings in the range of\n0.05-0.08 fm and pion masses down to 190 MeV. Our data indicate a non-zero\ndensity of eigenmodes near the origin and hence points to spontaneous chiral\nsymmetry breaking. We extrapolate our results to the continuum and chiral limit\nto give a result for the chiral condensate.",
        "positive": "Kaon B-parameter with NF=2 dynamical Wilson fermions: We present a preliminary study of the neutral kaon mixing bag parameter BK\nusing two flavors of dynamical Wilson fermions. We determine the matrix element\nof the relevant DeltaS=2 operator by using both the conventional approach and\nthe so called ``non-subtraction method'', and find that the latter leads to\nresults with smaller uncertainties. After having implemented non-perturbative\nrenormalization, we study the dependence of BK on the see quark mass. At our\nrelatively heavy values of quark masses (0.60<M_P/M_V<0.75) such a dependence\nis found to be negligible and the results, within the statistical accuracy, are\nconsistent with a quenched determination. As a preliminary result for the\nrenormalization group invariant parameter we quote BKRGI=1.02(25)."
    },
    {
        "anchor": "Hopping expansion as a tool for handling dual variables in lattice\n  models: The hopping expansion of 8-vertex models in their Grassmann representation is\nstudied. We use the functional similarity of the Ising model in this expansion\nwith the hopping expansion of 2-D Wilson fermions to show that the lattice\nfermions are equivalent to the Self-avoiding Loop Model at bending rigidity\n1/sqrt{2}.",
        "positive": "3--Dimensional Lattice Studies of the Electroweak Phase Transition at\n  M_{Higgs} approx 70 GeV: We study the electroweak phase transition by lattice simulations of an\neffective 3--dimensional theory, for a Higgs mass of about 70 GeV. Exploiting,\namong others, a variant of the equal weight criterion of phase equilibrium, we\nobtain transition temperature, latent heat and surface tension, and compare\nwith M_H approx 35 GeV. In the broken phase masses and Higgs condensates are\ncompared to perturbation theory. For the symmetric phase, bound state masses\nand the static force are determined."
    },
    {
        "anchor": "Quark confinement and the bosonic string: Using a new type of simulation algorithm for the standard SU(3) lattice gauge\ntheory that yields results with unprecedented precision, we confirm the\npresence of a $\\gamma/r$ correction to the static quark potential at large\ndistances $r$, with a coefficient $\\gamma$ as predicted by the bosonic string\ntheory. In both three and four dimensions, the transition from perturbative to\nstring behaviour is evident from the data and takes place at surprisingly small\ndistances.",
        "positive": "Complex-Temperature Singularities in the $d=2$ Ising Model. II.\n  Triangular Lattice: We investigate complex-temperature singularities in the Ising model on the\ntriangular lattice. Extending an earlier analysis of the low-temperature series\nexpansions for the (zero-field) susceptibility $\\bar\\chi$ by Guttmann\n\\cite{g75} to include the use of differential approximants, we obtain further\nevidence in support of his conclusion that the exponent describing the\ndivergence in $\\chi$ at $u=u_e=-1/3$ (where $u = e^{-4K}$) is $\\gamma_e'=5/4$\nand refine his estimate of the critical amplitude. We discuss the remarkable\nnature of this singularity, at which the spontaneous magnetisation diverges\n(with exponent $\\beta_e=-1/8$) and show that it lies at the endpoint of a\nsingular line segment constituting part of the natural boundaries of the free\nenergy in the complex $u$ plane. Using exact results, we find that the specific\nheat has a divergent singularity at $u=-1/3$ with exponent $\\alpha_e'=1$, so\nthat the relation $\\alpha_e'+2\\beta_e+\\gamma_e'=2$ is satisfied. We also study\nthe singularity at $u=u_s=-1$, where $M$ vanishes (with $\\beta_s=3/8$) and $C$\ndiverges logarithmically (with $\\alpha_s' = \\alpha_s = 0$)."
    },
    {
        "anchor": "A composite massless vector boson: In a non-perturbative gauge-invariant formulation of grand-unified theories\nall low energy vector states need to be composite with respect to the\nhigh-scale gauge group, including the photon. We investigate this by using\nlattice methods to spectroscopically analyze the vector channel in a toy\ngrand-unified theory, an SU(2) adjoint Higgs model. Our results support indeed\nthe existence of a massless composite vector particle.",
        "positive": "SU(2) lattice gauge theory in 2+1 dimensions: critical couplings from\n  twisted boundary conditions and universality: We present a precision determination of the critical coupling beta_c for the\ndeconfinement transition in pure SU(2) gauge theory in 2+1 dimensions. This is\npossible from universality, by intersecting the center vortex free energy as a\nfunction of the lattice coupling beta with the exactly known value of the\ninterface free energy in the 2D Ising model at criticality. Results for\nlattices with different numbers of sites N_t along the Euclidean time direction\nare used to determine how beta varies with temperature for a given N_t around\nthe deconfinement transition."
    },
    {
        "anchor": "Scattering of Goldstone Bosons and resonance production in a Composite\n  Higgs model on the lattice: We calculate the coupling between a vector resonance and two Goldstone bosons\nin $SU(2)$ gauge theory with $N_f=2$ Dirac fermions in the fundamental\nrepresentation. The considered theory can be used to construct a minimal\nComposite Higgs models. The coupling is related to the width of the vector\nresonance and we determine it by simulating the scattering of two Goldstone\nbosons where the resonance is produced. The resulting coupling is\n$g_{\\rm{VPP}}=7.8\\pm 0.6$, not far from $g_{\\rho\\pi \\pi}\\simeq 6$ in QCD. This\nis the first lattice calculation of the resonance properties for a minimal UV\ncompletion. This coupling controls the production cross section of the lightest\nexpected resonance at the LHC and enters into other tests of the Standard\nModel, from Vector Boson Fusion to electroweak precision tests. Our prediction\nis crucial to constrain the model using lattice input and for understanding the\nbehavior of the vector meson production cross section as a function of the\nunderlying gauge theory. We also extract the coupling $g_{\\rm{VPP}}^{\\rm{KSRF}}\n=9.4 \\pm 0.6$ assuming the vector-dominance and find that this phenomenological\nestimate slightly overestimates the value of the coupling.",
        "positive": "The L\u00fcscher scattering formalism on the $t$-channel cut: The L\\\"uscher scattering formalism, the standard approach for relating the\ndiscrete finite-volume energy spectrum to two-to-two scattering amplitudes,\nfails when analytically continued so far below the infinite-volume two-particle\nthreshold that one encounters the $t$-channel cut. This is relevant, especially\nin baryon-baryon scattering applications, as finite-volume energies can be\nobserved in this below-threshold regime, and it is not clear how to make use of\nthem. In this talk, we present a generalization of the scattering formalism\nthat resolves this issue, allowing one to also constrain scattering amplitudes\non the $t$-channel cut."
    },
    {
        "anchor": "B-physics from HQET in two-flavour lattice QCD: We present our analysis of B physics quantities using non-perturbatively\nmatched Heavy Quark Effective Theory (HQET) in Nf= 2 lattice QCD on the CLS\nensembles. Using all-to-all propagators, HYP-smeared static quarks, and the\nGeneralized Eigenvalue Problem (GEVP) approach with a conservative plateau\nselection procedure, we are able to systematically control all sources of\nerror. With significantly increased statistics compared to last year, our\npreliminary results are mb (mb) = 4.22(10)(4)z GeV for the MS b-quark mass, and\nfB = 193(9)stat (4)_\\chi MeV and fBs = 219(12)stat MeV for the B-meson decay\nconstants.",
        "positive": "Surface width of the Solid-On-Solid models: The low-temperature series for the surface width of the Absolute value\nSolid-On-Solid model and the Discrete Gaussian model both on the square lattice\nand on the triangular lattice are generated to high orders using the improved\nfinite-lattice method. The series are analyzed to give the critical points of\nthe roughening phase transition for each model."
    },
    {
        "anchor": "Gauge-invariant Renormalization of the Gluino-Glue operator: We study the Gluino-Glue operator in the context of Supersymmetric ${\\cal\nN}{=}1$ Yang-Mills (SYM) theory. This composite operator is gauge invariant,\nand it is directly connected to light bound states of the theory; its\nrenormalization is very important as a necessary step for the study of\nlow-lying bound states via numerical simulations. We make use of a\nGauge-Invariant Renormalization Scheme (GIRS). This requires the calculation of\nthe Green's function of a product of two Gluino-Glue operators, situated at\ndistinct space-time points. Within this scheme, the mixing with non-gauge\ninvariant operators which have the same quantum numbers is inconsequential. We\ncompute the one-loop conversion factor relating the GIRS scheme to\n$\\overline{\\rm MS}$. This conversion factor can be used in order to convert to\n$\\overline{\\rm MS}$ Green's functions which are obtained via lattice\nsimulations and are renormalized nonperturbatively in GIRS.",
        "positive": "The unitary Fermi gas at finite temperature: momentum distribution and\n  contact: The Unitary Fermi Gas (UFG) is one of the most strongly interacting systems\nknown to date, as it saturates the unitarity bound on the quantum mechanical\nscattering cross section. The UFG corresponds to a two-component Fermi gas in\nthe limit of short interaction range and large scattering length, and is\ncurrently realized in ultracold-atom experiments via Feshbach resonances. While\neasy to define, the UFG poses a challenging quantum many-body problem, as it\nlacks any characteristic scale other than the density. As a consequence,\naccurate quantitative predictions of the thermodynamic properties of the UFG\nrequire Monte Carlo calculations. However, significant progress has also been\nmade with purely analytical methods. Notably, in 2005 Tan derived a set of\nexact thermodynamic relations in which a universal quantity known as the\n\"contact\" C plays a crucial role. Recently, C has also been found to determine\nthe prefactor of the high- frequency power-law decay of correlators as well as\nthe right-hand-sides of shear- and bulk viscosity sum rules. The contact is\ntherefore a central piece of information on the UFG in equilibrium as well as\naway from equilibrium. In this talk we describe some of the known aspects of\nFermi gases at and around unitarity, show our latest Monte Carlo results for\nthe contact at finite temperature, and summarize the open questions in the\nfield, some of which we are starting to answer using large-scale Monte Carlo\ncalculations by adapting methods from Lattice QCD."
    },
    {
        "anchor": "Relationship between various supersymmetric lattice models: We comment on the relationships between several supersymmetric lattice\nmodels; the ``orbifold lattice theory'' by Cohen-Kaplan-Katz-Unsal (CKKU),\nlattice regularization of the topological field theory by Sugino and the\n``geometrical approach'' by Catterall. We point out that these three models\nhave close relationships; the N =(2,2) model by Catterall [Catterall] and the\ntwo-dimensional N = (2,2) lattice theory being similar to Sugino's construction\n[Sugino] can be derived by appropriate truncation of fields in the\ntwo-dimensional N = (4,4) orbifold lattice theory by CKKU [Cohen et al].\nCatterall's N = (2,2) description possesses extra degrees of freedom compared\nto the target N = (2,2) theory. If we remove those extra degrees of freedom in\na way keeping supersymmetry on the lattice, Catterall's description reduces to\na model of the Sugino type.",
        "positive": "Validity of ChPT -- is M_\u03c0=135 MeV small enough ?: I discuss the practical convergence of the SU(2) ChPT series in the meson\nsector, based on 2+1 flavor lattice data by the Wuppertal-Budapest and\nBudapest-Marseille-Wuppertal collaborations. These studies employ staggered and\nclover-improved Wilson fermions, respectively. In both cases large box volumes\nand several lattice spacings are used, and the pion masses reach down to the\nphysical mass point. We conclude that LO and NLO low-energy constants can be\ndetermined with controlled systematics, if there is sufficient data between the\nphysical mass point and about 350 MeV pion mass. Exploratory LO+NLO+NNLO fits\nwith a wider range reveal some distress of the chiral series near M_\\pi ~ 400\nMeV and suggest a complete breakdown beyond M_\\pi ~ 500 MeV."
    },
    {
        "anchor": "Testing the $SU(4)$ degeneracy after low-mode removal with $J=2$ mesons: Recent lattice results on Dirac low-mode removed $J=1,2$ mesons and\n$J=\\frac{1}{2}$ baryons reveal the appearance of a new $SU(4)$ symmetry of\nconfinement. Here the degeneracy of all $J=2$ iso-vector states within an\nirreducible representation of $SU(4)$ after low-mode removal is demonstrated.\nThe $SU(4)$ symmetry contains $SU(2)_L \\times SU(2)_R$ and $U(1)_A$ symmetries\nas subgroups and mixes all compontents $u_L,u_R,d_L,d_R$ of the two-flavor\nDirac field. It implies the vanishing of the interaction of quarks with the\ncolor-magnetic field, which is shown by using the QCD Hamiltonian in Coulomb\ngauge.",
        "positive": "The $\\big\\langle A^2 \\big\\rangle$ Asymmetry and Longitudinal Propagator\n  in Lattice $SU(2)$ Gluodynamics at $T\\simeq T_c$: We study numerically the chromoelectric-chromomagnetic asymmetry of the\ndimension two gluon condensate as well as the longitudinal gluon propagator at\n$T\\simeq T_c$ in the Landau-gauge $SU(2)$ lattice gauge theory. We show that\nsubstantial correlation between the asymmetry and the Polyakov loop as well as\nthe correlation between the longitudinal propagator and the Polyakov loop pave\nthe way to studies of the critical behavior of the asymmetry and the\nlongitudinal propagator. The respective values of critical exponents and\namplitudes are evaluated."
    },
    {
        "anchor": "Scale Determination Using the Static Potential with Two Dynamical Quark\n  Flavors: We study the static potential using gauge configurations that include the\neffects of two flavors of dynamical Kogut-Susskind quarks. The configurations,\ngenerated by the MILC collaboration, and used to study the spectrum and\nheavy-light decay constants, cover a range $5.3 \\le 6/g^2 \\le 5.6$. There are\nat least four quark masses for each coupling studied. Determination of $r_0$\nfrom the potential can be used to set a scale. This alternative scale is useful\nto study systematic errors on the spectrum and decay constants.",
        "positive": "The flavour projection of staggered fermions and the quarter-root trick: It is shown that the flavour projection of staggered fermions can be written\nas a projection between the fields on four separate, but parallel, lattices,\nwhere the fields on each are modified forms of the standard staggered fermion\nfield. Because the staggered Dirac operator acts equally on each lattice, it\nrespects this flavour projection. We show that the system can be gauged in the\nusual fashion and that this does not interfere with flavour projection. We also\nconsider the path integral, showing that, prior to flavour projection, it\nevaluates to the same form on each lattice and that this form is equal to that\nused in the quarter-root trick. The flavour projection leaves a path integral\nfor a single flavour of field on each lattice."
    },
    {
        "anchor": "Effective Lagrangian for the Polyakov line on a lattice: We formulate a method for computing the effective Lagrangian of the Polyakov\nline on the lattice. Using mean field approximation we calculate the effective\npotential for high temperatures. The result agrees with recent lattice\nsimulations. We reveal a new type of ultraviolet divergence (coming from\nlongitudinal gluons) which dominates the effective potential and explains the\ndiscrepancy of the lattice simulations and standard perturbative calculations\nperformed in covariant gauges.",
        "positive": "The M\u00f6bius Domain Wall Fermion Algorithm: We present a review of the properties of generalized domain wall Fermions,\nbased on a (real) M\\\"obius transformation on the Wilson overlap kernel,\ndiscussing their algorithmic efficiency, the degree of explicit chiral\nviolations measured by the residual mass ($m_{res}$) and the Ward-Takahashi\nidentities. The M\\\"obius class interpolates between Shamir's domain wall\noperator and Bori\\c{c}i's domain wall implementation of Neuberger's overlap\noperator without increasing the number of Dirac applications per conjugate\ngradient iteration. A new scaling parameter ($\\alpha$) reduces chiral\nviolations at finite fifth dimension ($L_s$) but yields exactly the same\noverlap action in the limit $L_s \\rightarrow \\infty$. Through the use of 4d\nRed/Black preconditioning and optimal tuning for the scaling $\\alpha(L_s)$, we\nshow that chiral symmetry violations are typically reduced by an order of\nmagnitude at fixed $L_s$. At large $L_s$ we argue that the observed scaling for\n$m_{res} = O(1/L_s)$ for Shamir is replaced by $m_{res} = O(1/L_s^2)$ for the\nproperly tuned M\\\"obius algorithm with $\\alpha = O(L_s)$"
    },
    {
        "anchor": "Determining the low energy parameters of Wilson Chiral Perturbation\n  Theory: We report preliminary results of a Wilson Chiral Perturbation Theory (WChPT)\nanalysis of twisted mass lattice QCD data. The quenched data, previously\npublished by two different groups, was generated with two definitions for the\ncritical quark mass and shows a strong non-linear quark mass dependence for\nsmall quark masses for the pion mass definition (``bending phenomenon''). We\nfind that WChPT describes this characteristic curvature fairly well. Fits to\nthe data provide estimates for combinations of low-energy parameters, even\nthough the errors are sizable.",
        "positive": "Constraining the QCD phase diagram by tricritical lines at imaginary\n  chemical potential: We present unambiguous evidence from lattice simulations of QCD with three\ndegenerate quark species for two tricritical points in the (T,m) phase diagram\nat fixed imaginary \\mu/T=i\\pi/3 mod 2\\pi/3, one in the light and one in the\nheavy mass regime. These represent the boundaries of the chiral and\ndeconfinement critical lines continued to imaginary chemical potential,\nrespectively. It is demonstrated that the shape of the deconfinement critical\nline for real chemical potentials is dictated by tricritical scaling and\nimplies the weakening of the deconfinement transition with real chemical\npotential. The generalization to non-degenerate and light quark masses is\ndiscussed."
    },
    {
        "anchor": "High Statistics Analysis using Anisotropic Clover Lattices: (III)\n  Baryon-Baryon Interactions: Low-energy baryon-baryon interactions are calculated in a high-statistics\nlattice QCD study on a single ensemble of anisotropic clover gauge-field\nconfigurations at a pion mass of m_\\pi ~ 390 MeV, a spatial volume of L^3 ~\n(2.5 fm)^3, and a spatial lattice spacing of b~0.123 fm. L\\\"uscher's method is\nused to extract nucleon-nucleon, hyperon-nucleon and hyperon-hyperon scattering\nphase shifts at one momentum from the one- and two-baryon ground-state energies\nin the lattice volume. The isospin-3/2 N\\Sigma interactions are found to be\nhighly spin-dependent, and the interaction in the ^3S_1 channel is found to be\nstrong. In contrast, the N\\Lambda interactions are found to be\nspin-independent, within the uncertainties of the calculation, consistent with\nthe absence of one-pion-exchange. The only channel for which a negative\nenergy-shift is found is \\Lambda\\Lambda, indicating that the \\Lambda\\Lambda\ninteraction is attractive, as anticipated from model-dependent discussions\nregarding the H-dibaryon. The NN scattering lengths are found to be small,\nclearly indicating the absence of any fine-tuning in the NN-sector at this pion\nmass. This is consistent with our previous Lattice QCD calculation of NN\ninteractions. The behavior of the signal-to-noise ratio in the baryon-baryon\ncorrelation functions, and in the ratio of correlation functions that yields\nthe ground-state energy splitting is explored. In particular, focus is placed\non the window of time slices for which the signal-to-noise ratio does not\ndegrade exponentially, as this provides the opportunity to extract quantitative\ninformation about multi-baryon systems.",
        "positive": "Instanton size distribution in O(3): We present calculations of the size distribution of instantons in the 2d O(3)\nnon-linear sigma-model, and briefly discuss the effects cooling has upon the\nconfigurations and the topological objects. (This preprint is also available\nvia anonymous ftp to suna.amtp.liv.ac.uk in /pub/pss/ as instdist.uue.)"
    },
    {
        "anchor": "A Lattice Study of Spin and Flavour Symmetry in Heavy Quark Physics: We present a first test of heavy quark spin-flavour symmetries in matrix\nelements for semi-leptonic decays \\bar B to D l\\bar\\nu and \\bar B to D^*\nl\\bar\\nu. We show that O(1/m_Q) corrections are small at masses around the\ncharm for form factors protected by Luke's Theorem, but are of order 30-40 \\%\nfor h_V and h_V/h_{A_{1}}.",
        "positive": "The critical point of lattice QCD on the \u03bc-T plane: We propose a method to study lattice QCD at finite temperature and chemical\npotential. We compare it with direct results and with the Glasgow method by\nusing n_f=4 QCD at Im(\\mu)\\neq 0. We locate the critical endpoint (E) of QCD on\nthe Re(\\mu)-T plane. In this study we use n_f=2+1 dynamical staggered quarks\nwith semi-realistic masses on L_t=4 lattices."
    },
    {
        "anchor": "The dimer partition function: We apply the Ginzburg criterion to the dimer problem and we solve the\napparent contradiction of a system with mean field $\\alpha={1\\over2}$, the\ntypical value of tricritical systems, and upper critical dimension $D_{cr}=6$.\nWe find that the system has upper critical dimension $D_{cr}=6$ , while for\n$D\\le4$ it should undergo a first order phase transition. We comment on the\nlatter wrong result examining the approximation we used.",
        "positive": "Monopoles of the Dirac type and color confinement in QCD -- Gauge\n  invariant mechansim: As a color confinement mechanism, a dual Meissner effect due to Abelian\nmonopoles involved in QCD has been discussed so far in various ways. But still\nthere is an important problem unsolved. It is gauge invariance of the schemes\nor, in other words, the reason why non-Abelian color confinement is explained\nby means of the Abelian dual Meissner effect. Here it is shown that a random\nAbelian method based on the violation of non-Abelian Bianchi identity (VNABI)\ncould prove SU(3) invariance and explain why color-singlets alone can survive\nin the confinement phase of QCD in the framework of the Abelian dual Meissner\neffect due to Abelian monopole condensation. This is completely different from\nthe 't Hooft's Abelian projection scheme which introduces an additional partial\ngauge-fixing or the idea of Bonati et al. which is based also on VNABI. Bonati\net al. say that VNABI is related to the 't Hooft tensor and the relation can\nprove the gauge invariance of the 't Hooft's Abelian projection schemes. But\nthe last idea is found to be incorrect. Existence of the relation between VNABI\nand the 't Hooft tensor alone can not account for gauge invariance of 't\nHooft's Abelian projection schemes."
    },
    {
        "anchor": "Non-perturbative improvement of bilinears in unquenched QCD: We describe how the improvement of quark bilinears generalizes from quenched\nto unquenched QCD, and discuss which of the additional improvement constants\ncan be determined using Ward Identities.",
        "positive": "The Topological Susceptibility of the Lattice CP(n-1) Model on the Torus\n  and the Sphere: The topological vacuum structure of the two-dimensional $~CP^{n-1}~$ model\nfor $~n = 3,5,7~$ is studied on the lattice. In particular we investigate the\nsmall-volume limit on the torus as well as on the sphere and compare with\ncontinuum results. For $~n \\ge 5~$ , where lattice artifacts should be\nsuppressed, the topological susceptibility shows unexpectedly strong deviations\nfrom asymptotic scaling. On the other hand there is an indication for a\nconvergence to values obtained analytically within the limit $~n \\rightarrow\n\\infty~$ ."
    },
    {
        "anchor": "Full QCD light hadron spectrum from the CP-PACS: We report on an on-going two-flavor full QCD study on CP-PACS using an\nRG-improved gauge action and a tadpole-improved SW quark action. Runs are made\nfor three lattice spacings $a^{-1}\\approx 0.9$, 1.3, and 2.5 GeV on\n$12^3\\times24$, $16^3\\times32$, and $24^3\\times48$ lattices. Four sea quark\nmasses having $m_{\\rm PS}/m_{\\rm V} \\approx 0.8$--0.6 are simulated, for each\nof which hadron masses are evaluated for valence quark masses corresponding to\n$m_{\\rm PS}/m_{\\rm V} \\approx 0.8$--0.5. Results for hadron and light quark\nmasses are presented and compared with those obtained in quenched QCD.",
        "positive": "Chiral phase transition in a lattice fermion--gauge--scalar model with\n  U(1) gauge symmetry: The chiral phase transition induced by a charged scalar field is investigated\nnumerically in a lattice fermion-gauge-scalar model with U(1) gauge symmetry,\nproposed recently as a model for dynamical fermion mass generation. For very\nstrong gauge coupling the transition is of second order and its scaling\nproperties are very similar to those of the Nambu--Jona-Lasinio model. However,\nin the vicinity of the tricritical point at somewhat weaker coupling, where the\ntransition changes the order, the scaling behavior is different. Therefore it\nis worthwhile to investigate the continuum limit of the model at this point."
    },
    {
        "anchor": "Conformal dimensions via large charge expansion: We construct an efficient Monte Carlo algorithm that overcomes the severe\nsignal-to-noise ratio problems and helps us to accurately compute the conformal\ndimensions of large-$Q$ fields at the Wilson-Fisher fixed point in the $O(2)$\nuniversality class. Using it we verify a recent proposal that conformal\ndimensions of strongly coupled conformal field theories with a global $U(1)$\ncharge can be obtained via a series expansion in the inverse charge $1/Q$. We\nfind that the conformal dimensions of the lowest operator with a fixed charge\n$Q$ are almost entirely determined by the first few terms in the series.",
        "positive": "Towards the spectrum of low-lying particles in supersymmetric Yang-Mills\n  theory: We present the current results of our simulations of N=1 supersymmetric\nYang-Mills theory on a lattice. The masses of the gluino-glue particle, the\na-eta-prime, the a-f0 meson, and the scalar glueball are obtained at finer\nlattice spacing than before, and extrapolations towards vanishing gluino mass\nare made. The calculations employ different levels of stout smearing. The\nstatistical accuracy as well as the control of finite size effects and lattice\nartefacts are better than in previous investigations. Taking the statistical\nand systematic uncertainties into account, the extrapolations towards vanishing\ngluino mass of the masses of the fermionic and bosonic states in our present\ncalculations are consistent with the formation of degenerate supermultiplets."
    },
    {
        "anchor": "Fluctuations, strangeness and quasi-quarks in heavy-ion collisions from\n  lattice QCD: We report measurements of diagonal susceptibilities for the baryon number,\nchi_B, electrical charge, chi_Q, third component of isospin, chi_I,\nstrangeness, chi_S, and hypercharge, chi_Y, as well as the off-diagonal chi_BQ,\nchi_BY, chi_BS, etc. We show that the ratios of susceptibilities in the high\ntemperature phase are robust variables, independent of lattice spacing, and\ntherefore give predictions for experiments. We also investigate strangeness\nproduction and flavour symmetry breaking matrix elements at finite temperature.\nFinally, we present evidence that in the high temperature phase of QCD the\ndifferent flavour quantum numbers are excited in linkages which are exactly the\nsame as one expects from quarks. We present some investigations of these\nquark-like quasi particles.",
        "positive": "The monopole content of topological clusters : have KvB calorons been\n  found?: Using smearing of equilibrium lattice fields generated at finite temperature\nin the confined phase of SU(2) lattice gauge theory, we have investigated the\nemerging topological objects (clusters of topological charge). Analysing their\nmonopole content according to the Polyakov gauge and the maximally Abelian\ngauge, we characterize part of them to correspond to nonstatic calorons or\nstatic dyons in the context of Kraan-van Baal caloron solutions with\nnon-trivial holonomy. The behaviour of the Polyakov loop inside these clusters\nand the (model-dependent) topological charges of these objects support this\ninterpretation."
    },
    {
        "anchor": "Study of unstable particle through the spectral function in O(4)\n  $\u03c6^4$ theory: We test application of the maximum entropy method to decompose the states\ncontributing to the unstable $\\sigma$ correlation function through the spectral\nfunction in the four dimensional O(4) $\\phi^4$ theory. Reliable results are\nobtained for the $\\sigma$ mass and two-particle $\\pi\\pi$ state energy using\nonly the $\\sigma$ correlation function. We also find that the property of the\n$\\sigma$ particle is different between the unstable ($m_{\\sigma}/m_{\\pi}>2$)\nand stable ($m_{\\sigma}/m_{\\pi}<2$) cases.",
        "positive": "Discretization effects on nucleon root-mean-square radii from lattice\n  QCD at the physical point: We present results for the axial-vector coupling and root-mean-square (RMS)\nradii of the nucleon obtained from 2+1 flavor lattice QCD at the physical point\nwith a large spatial extent of about 10 fm. Our calculations are performed with\nthe PACS10 gauge configurations generated by the PACS Collaboration with the\nsix stout-smeared $O(a)$ improved Wilson-clover quark action and Iwasaki gauge\naction at $\\beta$ = 1.82 and 2.00 corresponding to lattice spacings of 0.085 fm\nand 0.063 fm, respectively. We first evaluate the value of the axial-vector\ncoupling of the nucleon ($g_A$). In addition, the isovector electric, magnetic\nand axial radii and magnetic moment from the corresponding form factors are\nalso determined. Combining the results at $\\beta=1.82$ and $2.00$, we finally\ndiscuss the finite lattice spacing effect. It was found that the effect on\n$g_A$ is kept smaller than the statistical error of 2% while the effect on the\nisovector radii was observed as a possible discretization error of about 10%,\nregardless of the channel."
    },
    {
        "anchor": "Vus from pi and K decay constants in full lattice QCD with physical u,\n  d, s and c quarks: We determine the decay constants of the pi and K mesons on gluon field\nconfigurations from the MILC collaboration including u, d, s and c quarks. We\nuse three values of the lattice spacing and u/d quark masses going down to the\nphysical value. We use the w_0 parameter to fix the relative lattice spacing\nand f_pi to fix the overall scale. This allows us to obtain a value for\nf{K^+}/f{pi^+} = 1.1916(21). Comparing to the ratio of experimental leptonic\ndecay rates gives |Vus| = 0.22564(28){Br(K^+)}(20){EM}(40){latt}(5){Vud} and\nthe test of unitarity of the first row of the Cabibbo-Kobayashi-Maskawa matrix:\n|Vud|^2+|Vus|^2+|Vub|^2 - 1 = 0.00009(51).",
        "positive": "Heavy dense QCD and nuclear matter from an effective lattice theory: A three-dimensional effective lattice theory of Polyakov loops is derived\nfrom QCD by expansions in the fundamental character of the gauge action, u, and\nthe hopping parameter, \\kappa, whose action is correct to \\kappa^n u^m with\nn+m=4. At finite baryon density, the effective theory has a sign problem which\nmeets all criteria to be simulated by complex Langevin as well as by Monte\nCarlo on small volumes. The theory is valid for the thermodynamics of heavy\nquarks, where its predictions agree with simulations of full QCD at zero and\nimaginary chemical potential. In its region of convergence, it is moreover\namenable to perturbative calculations in the small effective couplings. In this\nwork we study the challenging cold and dense regime. We find unambiguous\nevidence for the nuclear liquid gas transition once the baryon chemical\npotential approaches the baryon mass, and calculate the nuclear equation of\nstate. In particular, we find a negative binding energy per nucleon causing the\ncondensation, whose absolute value decreases exponentially as mesons get\nheavier. For decreasing meson mass, we observe a first order liquid gas\ntransition with an endpoint at some finite temperature, as well as gap between\nthe onset of isospin and baryon condensation."
    },
    {
        "anchor": "Deconfinement transition and localization of Dirac modes in\n  finite-temperature $\\mathbb{Z}_3$ gauge theory on the lattice: We study the localization properties of the eigenmodes of the staggered Dirac\noperator across the deconfinement transition in finite-temperature\n$\\mathbb{Z}_3$ pure gauge theory on the lattice in 2+1 dimensions. This allows\nfor nontrivial tests of the sea-islands picture of localization, according to\nwhich low modes should localize on favorable Polyakov-loop fluctuations in the\ndeconfined phase of a gauge theory. We observe localized low modes in the\ndeconfined phase of the theory, both in the real Polyakov-loop sector, where\nthey are expected, and in the complex Polyakov-loop sectors, where they are\nnot. Our findings expose the limitations of the standard sea-islands picture,\nand call for its refinement. An improved picture, where spatial hopping terms\nplay a more prominent role, is proposed and found to be in excellent agreement\nwith numerical results.",
        "positive": "Density of states method for the Z(3) spin model: We apply the density of states approach to the Z(3) spin model with a\nchemical potential mu. For determining the density of states we use restricted\nMonte Carlo simulations on small intervals of the variable for the density. In\neach interval we probe the response of the system to the variation of a free\nparameter in the Boltzmann factor. This response is a known function which we\nfit to the Monte Carlo data and the parameters of the density are obtained from\nthat fit (functional fit approch; FFA). We evaluate observables related to the\nparticle number and the particle number susceptibility, as well as the free\nenergy. We find that for a surprisingly large range of mu the results from the\nFFA agree very well with the results from a reference simulation in the dual\nformulation of the Z(3) spin model which is free of the complex action problem."
    },
    {
        "anchor": "Towards $K\u03c0$ scattering with domain-wall fermions at the physical\n  point using distillation: Resonances play an important role in Standard Model phenomenology. In\nparticular, hadronic resonances feature in $B$ and $D$ decays, which can be\ncentral for New Physics searches. Lattice QCD simulations combined with the\nfinite-volume method can nowadays be used to reliably study strongly coupled\nscattering processes such as $K\\pi$ and thus the hadronic resonance $K^*$. In\nthis work, we approach $K\\pi$ scattering on a domain-wall $N_f = 2+1$ RBC-UKQCD\nensemble at a physical pion mass. We use the distillation method within Grid\nand Hadrons software to compute sets of operator basis. That allows solving an\neigenvalue problem to extract the low-energy finite-volume spectra, which are\nthen translated into scattering information. We update the state of the\ncalculation by reviewing the smearing process, outlining the variational\nanalysis and concluding by showing preliminary data.",
        "positive": "The equation of state for two flavor QCD at N_t=6: We calculate the two flavor equation of state for QCD on lattices with\nlattice spacing a=(6T)^{-1} and find that cutoff effects are substantially\nreduced compared to an earlier study using a=(4T)^{-1}. However, it is likely\nthat significant cutoff effects remain. We fit the lattice data to expected\nforms of the free energy density for a second order phase transition at\nzero-quark-mass, which allows us to extrapolate the equation of state to m_q=0\nand to extract the speed of sound. We find that the equation of state depends\nweakly on the quark mass for small quark mass."
    },
    {
        "anchor": "Charm Fluctuations and Deconfinement: We establish that the charmed hadrons start dissociating at the chiral\ncrossover temperature, ${T_{pc}}$, leading to the appearance of charm degrees\nfreedom carrying fractional baryon number. Our method is based on analyzing the\nsecond and fourth-order cumulants of charm (${C}$) fluctuations, and their\ncorrelations with baryon number (${B}$), electric charge (${Q}$) and\nstrangeness (${S}$) fluctuations. The first-time calculation of the ${QC}$\ncorrelations on the high statistics datasets of the HotQCD Collaboration\nenables us to disentangle the contributions from different electrically-charged\ncharm subsectors in the hadronic phase. In particular, we see an enhancement\nover the PDG expectation in the fractional contribution of the ${|Q|}=2$ charm\nsubsector to the total charm partial pressure for ${T<T_{pc}}$; this\nenhancement is in agreement with the Quark Model extended Hadron Resonance Gas\n(QM-HRG) model calculations. Furthermore, the agreement of QM-HRG calculations\nwith the projections onto charmed baryonic and mesonic correlations in\ndifferent charm subsectors indicates the existence of not-yet-discovered\ncharmed hadrons in all charm subsectors below ${T_{pc}}$. We aim at determining\nthe relevant degrees of freedom in temperature range ${T_{pc}<T<340 \\text{\nMeV}}$ by assuming the existence of a non-interacting gas of charmed\nquasi-particles composed of meson, baryon and quark-like excitations above\n$T_{pc}$. Our data suggest that the particles with quantum numbers consistent\nwith quarks start appearing at $T_{pc}$.",
        "positive": "Three-quark potentials in an $SU(3)$ effective Polyakov loop model: Three-quark potentials are studied in great details in the three-dimensional\n$SU(3)$ pure gauge theory at finite temperature, for the cases of static\nsources in the fundamental and adjoint representations. For this purpose, the\ncorresponding Polyakov loop model in its simplest version is adopted. The\npotentials in question, as well as the conventional quark--anti-quark\npotentials, are calculated numerically both in the confinement and\ndeconfinement phases. Results are compared to available analytical predictions\nat strong coupling and in the limit of large number of colors $N$. The\nthree-quark potential is tested against the expected $\\Delta$ and $Y$ laws and\nthe $3q$ string tension entering these laws is compared to the conventional\n$q\\bar{q}$ string tension. As a byproduct of this investigation, essential\nfeatures of the critical behaviour across the deconfinement transition are\nelucidated."
    },
    {
        "anchor": "Topological and magnetic properties of the QCD vacuum probed by overlap\n  fermions: We study some of the local CP-odd and magnetic properties of the non-Abelian\nvacuum with use of overlap fermions within the quenched lattice gauge theory.\nAmong these properties are the following: inhomogeneous spatial distribution of\nthe topological charge density (chirality for massless fermions) in SU(2)\ngluodynamics (for uncooled gauge configurations the chirality is localized on\nlow-dimensional defects with d=2..3, while a sequence of cooling steps gives\nrise to four-dimensional instantons and hence a four-dimensional structure of\nthe chirality distribution); finite local fluctuations of the chirality growing\nwith the strength of an external magnetic field; magnetization and\nsusceptibility of the QCD vacuum in SU(3) theory; magnetic catalysis of the\nchiral symmetry breaking, and the electric conductivity of the QCD vacuum in\nstrong magnetic fields.",
        "positive": "The mass of the Delta resonance in a finite volume: fourth-order\n  calculation: We calculate the self-energy of the Delta (1232) resonance in a finite\nvolume, using chiral effective field theory with explicit spin-3/2 fields. The\ncalculations are performed up-to-and-including fourth order in the small scale\nexpansion and yield an explicit parameterization of the energy spectrum of the\ninteracting pion-nucleon pair in a finite box in terms of both the quark mass\nand the box size L. It is shown that finite-volume corrections can be sizeable\nat small quark masses."
    },
    {
        "anchor": "Determination of $s$- and $p$-wave $I=1/2$ $K\u03c0$ scattering amplitudes\n  in $N_{\\mathrm{f}}=2+1$ lattice QCD: The elastic $I=1/2$, $s$- and $p$-wave kaon-pion scattering amplitudes are\ncalculated using a single ensemble of anisotropic lattice QCD gauge field\nconfigurations with $N_{\\mathrm{f}} = 2+1$ flavors of dynamical Wilson-clover\nfermions at $m_{\\pi} = 230\\mathrm{MeV}$. A large spatial extent of $L =\n3.7\\mathrm{fm}$ enables a good energy resolution while partial wave mixing due\nto the reduced symmetries of the finite volume is treated explicitly.The\n$p$-wave amplitude is well described by a Breit-Wigner shape with parameters\n$m_{K^{*}}/m_{\\pi} = 3.808(18)$ and $g^{\\mathrm{BW}}_{K^{*}K\\pi} = 5.33(20)$\nwhich are insensitive to the inclusion of $d$-wave mixing and variation of the\n$s$-wave parametrization. An effective range description of the near-threshold\n$s$-wave amplitude yields $m_{\\pi}a_0 = -0.353(25)$.",
        "positive": "Four-dimensional Simulation of the Hot Electroweak Phase Transition with\n  the SU(2) Gauge-Higgs Model: We study the finite-temperature electroweak phase transition of the minimal\nstandard model within the four-dimensional SU(2) gauge-Higgs model. Monte Carlo\nsimulations are performed for intermediate values of the Higgs boson mass in\nthe range $50 \\lesssim M_H \\lesssim 100$GeV on a lattice with the temporal size\n$N_t=2$. The order of the transition is systematically examined using\nfinite-size scaling methods. Behavior of the interface tension and the latent\nheat for an increasing Higgs boson mass is also investigated. Our results\nsuggest that the first-order transition terminates around $M_H \\sim 80$GeV."
    },
    {
        "anchor": "Responses of quark condensates to the chemical potential: The responses of quark condensates to the chemical potential, as a function\nof temperature T and chemical potential \\mu, are calculated within the\nNambu--Jona-Lasinio (NJL) model. We compare our results with those from the\nrecent lattice QCD simulations [QCD-TARO Collaboration, Nucl. Phys. B (Proc.\nSuppl.) 106, 462 (2002)]. The NJL model and lattice calculations show\nqualitatively similar behavior, and they will be complimentary ways to study\nhadrons at finite density. The behavior above T_c requires more elaborated\nanalyses.",
        "positive": "Quark Contraction Tool -- QCT: We present a Mathematica package for the calculation of Wick contractions in\nquantum field theories - QCT. Furthermore the package aims at automatically\ngenerating code for the calculation of physical matrix elements, suitable for\nnumerical evaluation in a C++ program. To that end commonly used algebraic\nmanipulations for the calculation of matrix elements in lattice QCD are\nimplemented."
    },
    {
        "anchor": "B_K with the Wilson Quark Action: A Non-Perturbative Resolution of\n  Operator Mixing using Chiral Ward Identities: We propose a non-perturbative method to determine the mixing coefficients of\n$\\Delta s=2$ four-quark operators for the Wilson quark action using chiral Ward\nidentities. The method is applied to calculate B_K in quenched QCD.",
        "positive": "N* Masses from an Anisotropic Lattice QCD Action: We report N* masses in the spin 3/2 sector from a highly-improved anisotropic\naction. States with both positive and negative parity are isolated via a parity\nprojection method. The extent to which spin projection is needed is examined.\nThe gross features of the splittings from the nucleon ground state show a trend\nconsistent with experimental results at the quark masses explored."
    },
    {
        "anchor": "Lattice QED in external electromagnetic fields: We study QED in external electromagnetic fields using methods developed for\nsimulating lattice QCD. Our first project is to simulate QED in a constant (in\nspace and time) external magnetic field on a euclidean space-time lattice using\nthe Rational Hybrid Monte Carlo (RHMC) method. Observables we measure include\nthe condensate $\\langle\\bar{\\psi}\\psi\\rangle$ and the effective electron action\nafter integrating out the fermion fields. We look for evidence that the\ncombined effect of the magnetic field and the electron-positron attraction from\nQED produces a non-zero condensate in the limit of zero electron mass, a\nnon-perturbative effect analogous to spontaneous chiral symmetry breaking. Very\npreliminary evidence is that such a condensate exists, at least for strong\nexternal magnetic fields and unphysically large electric charge. In addition,\nwe are storing field configurations to measure the expected distortions and\nscreenings of the coulomb field of a charged particle due to the vacuum\npolarization asymmetries produced by the magnetic field. We hope also to\nmeasure the dynamical contribution to the electron mass produced by the same\nmechanism that produces a finite condensate in the zero input mass limit.",
        "positive": "Logarithmic corrections to O($a$) and O($a^2$) effects in lattice QCD\n  with Wilson or Ginsparg-Wilson quarks: We derive the asymptotic lattice spacing dependence\n$a^n[2b_0\\bar{g}^2(1/a)]^{\\hat{\\Gamma}_i}$ relevant for spectral quantities of\nlattice QCD, when using Wilson, O$(a)$ improved Wilson or Ginsparg-Wilson\nquarks. We give some examples for the spectra encountered for $\\hat{\\Gamma}_i$\nincluding the partially quenched case, mixed actions and using two different\ndiscretisations for dynamical quarks. This also includes maximally twisted mass\nQCD relying on automatic O$(a)$ improvement. At O$(a^2)$, all cases considered\nhave $\\min_i\\hat{\\Gamma}_i\\gtrsim -0.3$ if $N_\\mathrm{f}\\leq 4$, which ensures\nthat the leading order lattice artifacts are not severely logarithmically\nenhanced in contrast to the O$(3)$ non-linear sigma model [1,2]. However, we\nfind a very dense spectrum of these leading powers, which may result in major\npile-ups and cancellations. We present in detail the computational strategy\nemployed to obtain the 1-loop anomalous dimensions already used in [3]."
    },
    {
        "anchor": "Meson screening masses from lattice QCD with two light and the strange\n  quark: We present results for screening masses of mesons built from light and\nstrange quarks in the temperature range of approximately between 140 MeV to 800\nMeV. The lattice computations were performed with 2+1 dynamical light and\nstrange flavors of improved (p4) staggered fermions along a line of constant\nphysics defined by a pion mass of about 220 MeV and a kaon mass of 500 MeV. The\nlattices had temporal extents Nt = 4, 6 and 8 and aspect ratios of Ns / Nt \\geq\n4. At least up to a temperature of 140 MeV the pseudo-scalar screening mass\nremains almost equal to the corresponding zero temperature pseudo-scalar (pole)\nmass. At temperatures around 3Tc (Tc being the transition temperature) the\ncontinuum extrapolated pseudo-scalar screening mass approaches very close to\nthe free continuum result of 2 \\pi T from below. On the other hand, at high\ntemperatures the vector screening mass turns out to be larger than the free\ncontinuum value of 2 \\pi T. The pseudo-scalar and the vector screening masses\ndo not become degenerate even for a temperature as high as 4Tc. Using these\nmesonic spatial correlation functions we have also investigated the restoration\nof chiral symmetry and the effective restoration of the axial symmetry. We have\nfound that the vector and the axial-vector screening correlators become\ndegenerate, indicating chiral symmetry restoration, at a temperature which is\nconsistent with the QCD transition temperature obtained in previous studies. On\nthe other hand, the pseudo-scalar and the scalar screening correlators become\ndegenerate only at temperatures larger than 1.3Tc, indicating that the\neffective restoration of the axial symmetry takes place at a temperature larger\nthan the QCD transition temperature.",
        "positive": "String tension and removal of lattice coarsening effects in Monte Carlo\n  Renormalization Group: We study the computation of the static quark potential under decimations in\nthe Monte Carlo Renormalization Group (MCRG). Employing a multi-representation\nplaquette action, we find that fine-tuning the decimation prescription so that\nthe MCRG equilibrium self-consistency condition is satisfied produces dramatic\nimprovement at large distances. In particular, lattice coarsening (change of\neffective lattice spacing on action-generated lattices after decimation) is\nnearly eliminated. Failure to correctly tune the decimation, on the other hand,\nproduces large coarsening effects, of order 50% or more, consistent with those\nseen in previous studies. We also study rotational invariance restoration at\nshort distances, where no particular improvement is seen for this action."
    },
    {
        "anchor": "Domain Wall Fermion Simulations with the Exact One-Flavor Algorithm: As algorithmic developments have driven down the cost of simulating\ndegenerate light quark flavors the relative cost of simulating single quark\nflavors with the Rational Hybrid Monte Carlo (RHMC) algorithm has become more\nexpensive. TWQCD has proposed an exact one-flavor algorithm (EOFA) that allows\nfor HMC simulations of a single quark flavor without taking a square root of\nthe fermion determinant. We have independently implemented EOFA in the Columbia\nPhysics System (CPS) and BAGEL Fermion Sparse-Matrix Library (BFM) for Shamir\nand M\\\"{o}bius domain wall fermions, and begun to optimize and test our\nimplementation against RHMC. In this talk we discuss the derivation of the EOFA\naction, our tests of its equivalence to RHMC, and the current state of our\nimplementation and optimization. We find, after introducing a novel\npreconditioning technique for the EOFA Dirac operator, that EOFA is a factor of\n2.4 times faster than RHMC per molecular dynamics trajectory for the strange\nquark determinant on an $N_{f} = 2+1$ M\\\"{o}bius DWF ensemble with physical\nquark masses and a $24^{3} \\times 64 \\times 24$ volume. We expect that further\nimprovement is possible by retuning the integrator parameters for EOFA and by\ncontinuing to optimize our code.",
        "positive": "Baryon resonances coupled to Pion-Nucleon states in lattice QCD: In recent years the study of two particle systems on the lattice has led to\nexcellent results in the meson sector of the QCD spectrum, however baryon\nresonances mostly remain unexplored. We present a study of pion-nucleon systems\nas decay product of baryon resonances in different channels, with special focus\non the nucleon spectrum. We evaluate the correlation functions of single and\nmulti particle interpolators. All the Wick contributions are explicitly\ncomputed and the consequences of reduced symmetries in moving frames are taken\ninto account. We discuss the theoretical setup together with results for\n$n_f=2$ mass degenerate light quarks."
    },
    {
        "anchor": "Neural multigrid for gauge theories and other disordered systems: We present evidence that multigrid works for wave equations in disordered\nsystems, e.g. in the presence of gauge fields, no matter how strong the\ndisorder, but one needs to introduce a \"neural computations\" point of view into\nlarge scale simulations: First, the system must learn how to do the simulations\nefficiently, then do the simulation (fast).\n  The method can also be used to provide smooth interpolation kernels which are\nneeded in multigrid Monte Carlo updates.",
        "positive": "The twisted gradient flow coupling at one loop: We compute the one-loop running of the $SU(N)$ 't Hooft coupling in a finite\nvolume gradient flow scheme using twisted boundary conditions. The coupling is\ndefined in terms of the energy density of the gradient flow fields at a scale\n$\\tilde{l}$ given by an adequate combination of the torus size and the rank of\nthe gauge group, and is computed in the continuum using dimensional\nregularization. We present the strategy to regulate the divergences for a\ngeneric twist tensor, and determine the matching to the $\\overline{\\rm MS}$\nscheme at one-loop order. For the particular case in which the twist tensor is\nnon-trivial in a single plane, we evaluate the matching coefficient numerically\nand determine the ratio of $\\Lambda$ parameters between the two schemes. We\nanalyze the $N$ dependence of the results and the possible implications for\nnon-commutative gauge theories and volume independence."
    },
    {
        "anchor": "nEDM from the theta-term and chromoEDM operators: In a previous work, we showed that unresolved excited state contaminations\nprovide a major source of systematic uncertainty in the calculation of the\nnucleon electric dipole moment due to the QCD topological term theta. Here we\nextend the calculation to the quark chromo-electric dipole moment operator\n(qcEDM). We also show quantitatively the impact of the mixing of the qcEDM with\nlower-dimensional operators on the lattice. Finally, we present preliminary\nresults from a unitary clover-on-clover calculation for the QCD topological\nterm.",
        "positive": "Theta dependence of the deconfinement temperature in Yang-Mills theories: We determine the theta dependence of the deconfinement temperature of SU(3)\npure gauge theory, finding that it decreases in presence of a topological theta\nterm. We do that by performing lattice simulations at imaginary theta, then\nexploiting analytic continuation. We also give an estimate of such dependence\nin the limit of a large number of colors N, and compare it with our numerical\nresults."
    },
    {
        "anchor": "Nucleon Charges from 2+1+1-flavor HISQ and 2+1-flavor clover lattices: Precise estimates of the nucleon charges $g_A$, $g_S$ and $g_T$ are needed in\nmany phenomenological analyses of SM and BSM physics. In this talk, we present\nresults from two sets of calculations using clover fermions on 9 ensembles of\n2+1+1-flavor HISQ and 4 ensembles of 2+1-flavor clover lattices. We show that\nhigh statistics can be obtained cost-effectively using the truncated solver\nmethod with bias correction and the coherent source sequential propagator\ntechnique. By performing simulations at 4--5 values of the source-sink\nseparation $t_{\\rm sep}$, we demonstrate control over excited-state\ncontamination using 2- and 3-state fits. Using the high-precision 2+1+1-flavor\ndata, we perform a simultaneous fit in $a$, $M_\\pi$ and $M_\\pi L$ to obtain our\nfinal results for the charges.",
        "positive": "Magnetic polarizability of hadrons from lattice QCD: We extract the magnetic polarizability from the quadratic response of a\nhadron's mass shift in progressively small static magnetic fields. The\ncalculation is done on a 24x12x12x24 lattice at a = 0.17 fm with an improved\ngauge action and the clover quark action. The results are compared to those\nfrom experiments and models where available."
    },
    {
        "anchor": "Topological susceptibility, scale setting and universality from\n  $Sp(N_c)$ gauge theories: In this contribution, we report on our study of the properties of the Wilson\nflow and on the calculation of the topological susceptibility of $Sp(N_c)$\ngauge theories for $N_c=2,\\,4,\\,6,\\,8$. The Wilson flow is shown to scale\naccording to the quadratic Casimir operator of the gauge group, as was already\nobserved for $SU(N_c)$, and the commonly used scales $t_0$ and $w_0$ are\nobtained for a large interval of the inverse coupling for each probed value of\n$N_c$. The continuum limit of the topological susceptibility is computed and we\nconjecture that it scales with the dimension of the group. The lattice\nmeasurements performed in the $SU(N_c)$ Yang-Mills theories by several\nindependent collaborations allow us to test this conjecture and to obtain a\nuniversal large-$N_c$ limit of the rescaled topological susceptibility.",
        "positive": "Four fermion operators and the search for BSM Physics: We report on Monte Carlo simulations focused on elucidating the phase\nstructure of a SU(2) gauge theory containing $N_f$ Dirac fermion flavors\ntransforming in the fundamental representation of the group and interacting\nthrough an additional chirally invariant four fermion term. Pairs of physical\nflavors are implemented using the two tastes present in a reduced staggered\nfermion formulation of the theory with the Yukawa interactions necessary for\ngenerating the four fermion term preserving the usual shift symmetries. We\nobserve a crossover in the behavior of the chiral condensate for strong four\nfermi coupling associated with the generation of a dynamical mass for the\nfermions. At weak gauge coupling this crossover is consistent with the usual\ncontinuous phase transition seen in the pure (ungauged) NJL model. However, if\nthe gauge coupling is strong enough to cause confinement we observe a much more\nrapid crossover in the chiral condensate consistent with a first order phase\ntransition."
    },
    {
        "anchor": "SU(3) lattice gauge theory with a mixed fundamental and adjoint\n  plaquette action: Lattice artefacts: We study the four-dimensional SU(3) gauge model with a fundamental and an\nadjoint plaquette term in the action. We investigate whether corrections to\nscaling can be reduced by using a negative value of the adjoint coupling. To\nthis end, we have studied the finite temperature phase transition, the static\npotential and the mass of the 0^{++} glueball. In order to compute these\nquantities we have implemented variance reduced estimators that have been\nproposed recently. Corrections to scaling are analysed in dimensionless\ncombinations such as T_c/\\sqrt{\\sigma} and m_{0^{++}}/T_c. We find that indeed\nthe lattice artefacts in e.g. m_{0^{++}}/T_c can be reduced considerably\ncompared with the pure Wilson (fundamental) gauge action at the same lattice\nspacing.",
        "positive": "Singular Behaviour of the Potts Model in the Thermodynamic Limit: The self-duality transformation is applied to the Fisher zeroes near the\ncritical point in the thermodynamic limit in the q>4 state Potts model in two\ndimensions. A requirement that the locus of the duals of the zeroes be\nidentical to the dual of the locus of zeroes (i) recovers the ratio of specific\nheat to internal energy discontinuity at criticality and the relationships\nbetween the discontinuities of higher cumulants and (ii) identifies duality\nwith complex conjugation. Conjecturing that all zeroes governing ferromagnetic\ncritical behaviour satisfy the latter requirement, the full locus of Fisher\nzeroes is shown to be a circle. This locus, together with the density of zeroes\nis shown to be sufficient to recover the singular form of all thermodynamic\nfunctions in the thermodynamic limit."
    },
    {
        "anchor": "Heavy-light meson decay constants from NRQCD: an analysis of the 1/M\n  corrections: We present {\\it preliminary} results for the decay constants of heavy-light\nmesons using NRQCD heavy and tadpole improved Clover light quarks. A comparison\nis made with data obtained using Wilson light quarks. We present an analysis of\nthe 1/M corrections to the decay constants in the static limit and compare with\nthe predictions of HQET.",
        "positive": "$B \\rightarrow \u03c0\\ell \u03bd$ with M\u00f6bius Domain Wall Fermions: We report on the status of our calculation of the exclusive semileptonic\ndecay, $B\\rightarrow \\pi \\ell \\nu$; a key process in the determination of the\nCKM matrix element $|V_{ub}|$. The M\\\"{o}bius domain wall action is used for\nboth light and heavy quarks on gauge ensembles that include the effects of\n$2+1$ flavours of quarks in the sea at three values of the lattice spacing:\n$a\\approx 0.08~\\mathrm{fm}$, $a\\approx0.055~\\mathrm{fm}$, and\n$a\\approx0.044~\\mathrm{fm}$. Pion masses go down to $300~\\mathrm{MeV}$ while\nheavy quarks masses are as large as $2.44m_c$. We present preliminary results\nof form factors from this process, showing dependence on momentum transfer,\nlattice spacing, and the heavy quark mass."
    },
    {
        "anchor": "B meson leptonic decay constant with quenched lattice NRQCD: We present a lattice NRQCD study of the B meson decay constant in the\nquenched approximation with emphasis given to the scaling behavior. The NRQCD\naction and the heavy-light axial current we use include all terms of order 1/M\nand the perturbative $O(\\alpha_s a)$ and $O(\\alpha_s/M)$ corrections. Using\nsimulations at three value of couplings $\\beta$=5.7, 5.9 and 6.1 on lattices of\nsize $12^3\\times 32, 16^3\\times 48$ and $24^3\\times 64$, we find no significant\n$a$ dependence in $f_B$ if the $O(\\alpha_s a)$ correction is included in the\naxial current. We obtain $f_B = 167(7)(15)$ MeV, $f_{B_s}=\n191(4)(17)(^{+4}_{-0})$ MeV and $f_{B_s}/f_B =1.15(3)(1)(^{+3}_{-0})$, with the\nfirst error being statistical, the second systematic, and the third due to\nuncertainty of strange quark mass, while quenching errors being not included.",
        "positive": "$B \\to D^* l \u03bd$ with staggered chiral perturbation theory: An unquenched calculation of the form factor for $B\\to D^* l \\nu$ is needed\nto improve the determination of $|V_{cb}|$. The MILC lattices, computed with a\n2+1 improved staggered action for the light quarks, are well suited to this\npurpose. The relevant staggered chiral perturbation theory (SChPT) must be\nknown in order to correctly account for the \"taste\" breaking discretization\neffects associated with the staggered quarks to NLO in $1/ m_{D^*}$. This SChPT\ncalculation is presented."
    },
    {
        "anchor": "Pseudoscalar meson physics with four dynamical quarks: We present preliminary results for light, strange and charmed pseudoscalar\nmeson physics from simulations using four flavors of dynamical quarks with the\nhighly improved staggered quark (HISQ) action. These simulations include\nlattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above\nand at their physical value. The major results are charm meson decay constants\nf_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus\non our procedures for finding the decay constants on each ensemble, the\ncontinuum extrapolation, and estimates of systematic error.",
        "positive": "Double-pass variants for multi-shift BiCGstab(ell): In analogy to Neuberger's double-pass algorithm for the Conjugate Gradient\ninversion with multi-shifts we introduce a double-pass variant for\nBiCGstab(ell). One possible application is the overlap operator of QCD at\nnon-zero chemical potential, where the kernel of the sign function is\nnon-Hermitian. The sign function can be replaced by a partial fraction\nexpansion, requiring multi-shift inversions. We compare the performance of the\nnew method with other available algorithms, namely partial fraction expansions\nwith restarted FOM inversions and the Krylov-Ritz method using nested Krylov\nsubspaces."
    },
    {
        "anchor": "Evidence for a Bound H-dibaryon from Lattice QCD: We present evidence for the existence of a bound H-dibaryon, an I=0, J=0,\ns=-2 state with valence quark structure uuddss, at a pion mass of m_pi ~ 389\nMeV. Using the results of Lattice QCD calculations performed on four ensembles\nof anisotropic clover gauge-field configurations, with spatial extents of L ~\n2.0, 2.5, 3.0 and 3.9 fm at a spatial lattice spacing of b ~ 0.123 fm, we find\nan H-dibaryon bound by B = 16.6 +- 2.1 +- 4.6 MeV at a pion mass of m_pi ~ 389\nMeV.",
        "positive": "Accelerating Staggered Fermion Dynamics with the Rational Hybrid Monte\n  Carlo (RHMC) Algorithm: Improved staggered fermion formulations are a popular choice for lattice QCD\ncalculations. Historically, the algorithm used for such calculations has been\nthe inexact R algorithm, which has systematic errors that only vanish as the\nsquare of the integration step-size. We describe how the exact Rational Hybrid\nMonte Carlo (RHMC) algorithm may be used in this context, and show that for\nparameters corresponding to current state-of-the-art computations it leads to a\nfactor of approximately seven decrease in cost as well as having no step-size\nerrors."
    },
    {
        "anchor": "Pion form factor with twisted mass QCD: The pion form factor is calculated using quenched twisted mass QCD with\nbeta=6.0 and maximal twisting angle omega=pi/2. Two pion masses and several\nvalues of momentum transfer are considered. The momentum averaging procedure of\nFrezzotti and Rossi is used to reduce lattice spacing errors, and numerical\nresults are consistent with the expected O(a) improvement.",
        "positive": "Classification and Generalization of Minimal-doubling actions: We propose a method to control the number of species of lattice fermions,\nwhich yields new classes of minimally doubled lattice fermions with one exact\nchiral symmetry and exact locality. We classify all the known minimally doubled\nfermions into two types based on the locations of the propagator poles in the\nBrillouin zone. We also study higher-dimensional extension of them and show it\ntends to be more difficult to realize minimal-doubling in higher dimensions."
    },
    {
        "anchor": "Spectrum of the SU(3) Dirac operator on the lattice: Transition from\n  random matrix theory to chiral perturbation theory: We calculate complete spectra of the Kogut-Susskind Dirac operator on the\nlattice in quenched SU(3) gauge theory for various values of coupling constant\nand lattice size. From these spectra we compute the connected and disconnected\nscalar susceptibilities and find agreement with chiral random matrix theory up\nto a certain energy scale, the Thouless energy. The dependence of this scale on\nthe lattice volume is analyzed. In the case of the connected susceptibility\nthis dependence is anomalous, and we explain the reason for this. We present a\nmodel of chiral perturbation theory that is capable of describing the data\nbeyond the Thouless energy and that has a common range of applicability with\nchiral random matrix theory.",
        "positive": "Image-processing the topological charge density in the CP(N-1) model: We study the topological charge density distribution using the\ntwo-dimensional $CP^{N-1}$ model. We numerically compute not only the\ntopological susceptibility, which is a spatially global quantity to probe\ntopological properties of the whole system, but also the topological charge\ncorrelator with finite momentum. We perform Fourier power spectrum analysis for\nthe topological charge density for various values of the inverse temperature\n$\\beta$. We propose to utilize the Fourier entropy as a convenient measure to\ncharacterize spatial distribution patterns and demonstrate that the Fourier\nentropy exhibits nontrivial temperature dependence. We also consider the\nsnapshot entropy defined with the singular value decomposition, which also\nturns out to behave nonmonotonically with the temperature. We give a possible\ninterpretation suggested from the strong-coupling analysis."
    },
    {
        "anchor": "Complex-Temperature Singularities in the $d=2$ Ising Model. III.\n  Honeycomb Lattice: We study complex-temperature properties of the uniform and staggered\nsusceptibilities $\\chi$ and $\\chi^{(a)}$ of the Ising model on the honeycomb\nlattice. From an analysis of low-temperature series expansions, we find\nevidence that $\\chi$ and $\\chi^{(a)}$ both have divergent singularities at the\npoint $z=-1 \\equiv z_{\\ell}$ (where $z=e^{-2K}$), with exponents\n$\\gamma_{\\ell}'= \\gamma_{\\ell,a}'=5/2$. The critical amplitudes at this\nsingularity are calculated. Using exact results, we extract the behaviour of\nthe magnetisation $M$ and specific heat $C$ at complex-temperature\nsingularities. We find that, in addition to its zero at the physical critical\npoint, $M$ diverges at $z=-1$ with exponent $\\beta_{\\ell}=-1/4$, vanishes\ncontinuously at $z=\\pm i$ with exponent $\\beta_s=3/8$, and vanishes\ndiscontinuously elsewhere along the boundary of the complex-temperature\nferromagnetic phase. $C$ diverges at $z=-1$ with exponent $\\alpha_{\\ell}'=2$\nand at $v=\\pm i/\\sqrt{3}$ (where $v = \\tanh K$) with exponent $\\alpha_e=1$, and\ndiverges logarithmically at $z=\\pm i$. We find that the exponent relation\n$\\alpha'+2\\beta+\\gamma'=2$ is violated at $z=-1$; the right-hand side is 4\nrather than 2. The connections of these results with complex-temperature\nproperties of the Ising model on the triangular lattice are discussed.",
        "positive": "Charmed and $\u03c6$ meson decay constants from 2+1-flavor lattice QCD: On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical\npion mass, we calculate the decay constants of $D_{s}^{(*)}$, $D^{(*)}$ and\n$\\phi$. The lattice size is $48^3\\times96$, which corresponds to a spatial\nextension of $\\sim5.5$ fm with the lattice spacing $a\\approx 0.114$ fm. For the\nvalence light, strange and charm quarks, we use overlap fermions at several\nmass points close to their physical values. Our results at the physical point\nare $f_D=213(5)$ MeV, $f_{D_s}=249(7)$ MeV, $f_{D^*}=234(6)$ MeV,\n$f_{D_s^*}=274(7)$ MeV, and $f_\\phi=241(9)$ MeV. The couplings of $D^*$ and\n$D_s^*$ to the tensor current ($f_V^T$) can be derived, respectively, from the\nratios $f_{D^*}^T/f_{D^*}=0.91(4)$ and $f_{D_s^*}^T/f_{D_s^*}=0.92(4)$, which\nare the first lattice QCD results. We also obtain the ratios\n$f_{D^*}/f_D=1.10(3)$ and $f_{D_s^*}/f_{D_s}=1.10(4)$, which reflect the size\nof heavy quark symmetry breaking in charmed mesons. The ratios\n$f_{D_s}/f_{D}=1.16(3)$ and $f_{D_s^*}/f_{D^*}=1.17(3)$ can be taken as a\nmeasure of SU(3) flavor symmetry breaking."
    },
    {
        "anchor": "Approaching the chiral point in two-flavour lattice simulations: We investigate the behaviour of the pion decay constant and the pion mass in\ntwo-flavour lattice QCD, with the physical and chiral points as ultimate goal.\nMeasurements come from the ensembles generated by the CLS initiative using the\nO(a)-improved Wilson formulation, with lattice spacing down to about 0.05 fermi\nand pion masses as low as 190 MeV. The applicability of SU(2) chiral\nperturbation theory is investigated, and various functional forms, and their\nrange of validity, are compared. The physical scale is set through the kaon\ndecay constant, whose measurement is enabled by inserting a third, heavier\nvalence strange quark.",
        "positive": "Towards a Non-Perturbative Calculation of DIS Wilson Coefficients: We verify the operator product expansion (OPE) of deep inelastic scattering\n(DIS) on the lattice and present first results of a non-perturbative\ncalculation of the Wilson coefficients."
    },
    {
        "anchor": "Vortices, Symmetry Breaking, and Temporary Confinement in SU(2)\n  Gauge-Higgs Theory: We further investigate center vortex percolation and Coulomb gauge remnant\nsymmetry breaking in the SU(2) gauge-Higgs model. We show that string breaking\nis visible in Polyakov line correlators on the center projected lattice, that\nour usual numerical tests successfully relate P-vortices to center vortices,\nand that vortex removal removes the linear potential, as in the pure gauge\ntheory. This data suggests that global center symmetry is not essential to the\nvortex confinement mechanism. But we also find that the line of vortex\npercolation-depercolation transitions, and the line of remnant symmetry\nbreaking transitions, do not coincide in the SU(2)-Higgs phase diagram. This\nnon-uniqueness of transition lines associated with non-local order parameters\nfavors a straightforward interpretation of the Fradkin-Shenker theorem, namely:\nthere is no unambiguous distinction, in the SU(2) gauge-Higgs models, between a\n\"confining\" phase and a Higgs phase.",
        "positive": "$G_2$-QCD: Spectroscopy and the phase diagram at zero temperature and\n  finite density: Due to the fermion sign problem, standard lattice Monte-Carlo method for QCD\nfail at small temperatures and high baryon densities. $G_2$-QCD, QCD with the\ngauge group $SU(3)$ replaced by the exceptional Lie group $G_2$, can be\nsimulated using lattice techniques at these densities, and can therefore\nprovide an illustration of the possible phase structure. Here we present a\nsystematic investigation of the ground-state hadronic spectrum using lattice\nsimulations for different quark masses in several hadronic sectors. We then\nshow that the different hadronic scales of Goldstone bosons, intermediate\nbosons, and baryons is reflected in the phase structure at finite density."
    },
    {
        "anchor": "Lattice and renormalons in heavy quark physics: Perturbative expansions of QCD observables in powers of $\\alpha_s$ are\nbelieved to be asymptotic and non-Borel summable due to the existence of\nsingularities in the Borel plane (renormalons). This fact is connected with the\nfactorization of scales (which is inherent to QCD and asymptotic freedom) and\njeopardizes the convergence of the perturbative expansion and the accurate\ndetermination of power-suppressed corrections. This problem is more acute for\nphysical systems composed by one or more heavy quarks. In lattice regulations,\nit reflects on the appearance of power-like divergences in the inverse of the\nlattice spacing for a series of quantities ($\\bar \\Lambda$, gluelump masses,\nthe singlet and hybrid potentials, ...) making that the continuum limit can not\nbe reached for them. Nevertheless, all these problems are solved within the\nframework of effective field theories with renormalon substraction. This allows\nus to obtain convergent perturbative series and to unambiguously define power\ncorrections. In particular, one can connect with lattice results. Remarkably\nenough the dependence on the lattice spacing can be predicted by perturbation\ntheory. This framework has been applied to the prediction of the gluelump\nmasses and the singlet and octet (hybrid) potentials at short distances, as\nwell as to their comparison with lattice simulations. Overall, very good\nagreement with data is obtained.",
        "positive": "Are Topological Charge Fluctuations in QCD Instanton Dominated?: We consider a recent proposal by Horv\\'ath {\\em et al.} to address the\nquestion whether topological charge fluctuations in QCD are instanton dominated\nvia the response of fermions using lattice fermions with exact chiral symmetry,\nthe overlap fermions. Considering several volumes and lattice spacings we find\nstrong evidence for chirality of a finite density of low-lying eigenvectors of\nthe overlap-Dirac operator in the regions where these modes are peaked. This\nresult suggests instanton dominance of topological charge fluctuations in\nquenched QCD."
    },
    {
        "anchor": "Screening correlators with chiral Fermions: We study screening correlators of quark-antiquark composites at T=2T_c, where\nT_c is the QCD phase transition temperature, using overlap quarks in the\nquenched approximation of lattice QCD. As the lattice spacing is changed from\n1/4T to a=1/6T and 1/8T, we find that screening correlators change little, in\ncontrast with the situation for other types of lattice fermions. All\ncorrelators are close to the ideal gas prediction at small separations. The\nlong distance falloff is clearly exponential, showing that a parametrization by\na single screening length is possible at distances z > 1/T. The correlator\ncorresponding to the thermal vector is close to the ideal gas value at all\ndistances, whereas that for the thermal scalar deviates at large distances.\nThis is examined through the screening lengths and momentum space correlators.\nThere is strong evidence that the screening transfer matrix does not have\nreflection positivity.",
        "positive": "Lattice Regularized QCD at Finite Temperature: During the first part of this review we will focus on the thermodynamics of\n$SU(N)$ gauge theories at finite temperature. We will present results from a\ncalculation of electric and magnetic screening masses for the gluons, discuss\ncalculations of the critical temperature in units of the string tension and\nbulk thermodynamic quantities like the energy density and pressure. In\nparticular, the latter calculations have now reached a stage where $O(a^2)$\ncut-off effects can be controlled systematically and an extrapolation to the\ncontinuum limit can be performed. In the second part we discuss the critical\nbehaviour of QCD with light quarks. We analyze the chiral transition in\n2-flavour QCD and present results on the temperature dependence of hadron\nproperties."
    },
    {
        "anchor": "A Comparative Analysis between Unbiased Exponential Resummation and\n  Taylor Expansion in Finite-Density QCD with a new phasefactor for Isospin: The recently introduced unbiased exponential resummation at finite chemical\npotential has become an important approach which promises to capture reliably\nthe behaviour of higher order conserved charge cumulants appearing otherwise in\nthe finite-density QCD Taylor series of thermodynamic observables. In this\npaper, we present a thorough analysis of the estimates of charge cumulants upto\neighth order and have compared them using Taylor expansion method and unbiased\nexponential resummation approach for baryon and isospin chemical potentials. We\nalso subsequently compare the different estimates of the radius of convergence\nobtained using these two methods and check if the zeros of phasefactor for\nbaryochemical potential can indicate something about these estimated values. We\npropose a new method of finding a non-trivial phasefactor for isospin chemical\npotential and we attempt explaining the different estimates of radius of\nconvergence from the zeroes of this newly constructed gauge-ensemble average\nphasefactor for isospin chemical potential. Lastly, we also illustrate kurtosis\nplots describing the behaviour of overlap problem in isospin chemical potential\nand check if it maintains consistency with the appearance of zeros of the newly\nproposed phasefactor.",
        "positive": "Beta function of three-dimensional QED: We have carried out a Schrodinger-functional calculation for the Abelian\ngauge theory with Nf=2 four-component fermions in three dimensions. We find no\nfixed point in the beta function, meaning that the theory is confining rather\nthan conformal."
    },
    {
        "anchor": "Investigation of light and heavy tetraquark candidates using lattice QCD: We review the status of an ongoing long-term lattice investigation of the\nspectrum and structure of tetraquark candidates. We focus on the light scalar\nmeson $a_0(980)$. First steps regarding the study of a possibly existing $c c\n\\bar{c} \\bar{c}$ tetraquark are also outlined.",
        "positive": "Investigations in 1+1 dimensional lattice $\u03c6^4$ theory: In this work we perform a detailed numerical analysis of (1+1) dimensional\nlattice $\\phi^4$ theory. We explore the phase diagram of the theory with two\ndifferent parameterizations. We find that symmetry breaking occurs only with a\nnegative mass-squared term in the Hamiltonian. The renormalized mass $m_R$ and\nthe field renormalization constant $Z$ are calculated from both coordinate\nspace and momentum space propagators in the broken symmetry phase. The critical\ncoupling for the phase transition and the critical exponents associated with\n$m_R$, $Z$ and the order parameter are extracted using a finite size scaling\nanalysis of the data for several volumes. The scaling behavior of $Z$ has the\ninteresting consequence that $<\\phi_R>$ does not scale in 1+1 dimensions. We\nalso calculate the renormalized coupling constant $ \\lambda_R$ in the broken\nsymmetry phase. The ratio $ \\lambda_R/m_R^2 $ does not scale and appears to\nreach a value independent of the bare parameters in the critical region in the\ninfinite volume limit."
    },
    {
        "anchor": "Hadronic vacuum polarization in finite volume using NNLO ChPT: We present results for the leading hadronic contribution to the muon $g-2$\nfrom configurations with 2+1+1 flavors of HISQ quarks. The ensembles have been\ngenerated by the MILC collaboration at three lattice spacings. Using the\ntime-momentum representation of the electromagnetic current correlator, we\ncalculate the finite volume effects up to next-to-next-to-leading-order in\nChiral Perturbation Theory.",
        "positive": "Chiral Fermions on the Lattice: A recently proposed method for regularizing chiral gauge theories\nnon-perturbatively is discussed in detail. The result is an effective action\nwhich can be computed from the lattice gauge field, and which is suited for\nnumerical simulations."
    },
    {
        "anchor": "The universality class of the electroweak theory: We study the universality class and critical properties of the electroweak\ntheory at finite temperature. Such critical behaviour is found near the\nendpoint m_H=m_{H,c} of the line of first order electroweak phase transitions\nin a wide class of theories, including the Standard Model (SM) and a part of\nthe parameter space of the Minimal Sypersymmetric Standard Model (MSSM). We\nfind that the location of the endpoint corresponds to the Higgs mass m_{H,c} =\n72(2) GeV in the SM with sin^2 theta_W = 0, and m_{H,c} < 80 GeV with sin^2\ntheta_W = 0.23. As experimentally m_H > 88 GeV, there is no electroweak phase\ntransition in the SM. We compute the corresponding critical indices and provide\nstrong evidence that the phase transitions near the endpoint fall into the\nthree dimensional Ising universality class.",
        "positive": "Extracting the low-energy constant $L_0^r$ at three flavors from\n  pion-kaon scattering: Based on our analysis of the contributions from the connected and\ndisconnected contraction diagrams to the pion-kaon scattering amplitude, we\nprovide the first determination of the only free low-energy constant at\n$\\mathcal{O}(p^4)$, known as $L_0^r$, in SU$(4|1)$ Partially-Quenched Chiral\nPerturbation Theory using the data from the Extended Twisted Mass\nCollaboration, $L_0^r(\\mu=M_\\rho) = 0.77(20)(25)(7)(7)(2)\\cdot 10^{-3}$. The\ntheory uncertainties originate from the unphysical scattering length, the\nphysical low-energy constants, the higher-oder chiral corrections, the\n(lattice) meson masses and the pion decay constant, respectively"
    },
    {
        "anchor": "Chiral observables and topology in hot QCD with two families of quarks: We present results on QCD with four dynamical flavors in the temperature\nrange $150$ MeV $\\lesssim T \\lesssim 500$ MeV. We have performed lattice\nsimulations with Wilson fermions at maximal twist and measured Polyakov loop,\nchiral condensate and disconnected susceptibility, on lattices with spacings as\nfine as 0.065 fm. For most observables spacing effects are below statistical\nerrors, which enables us to identify lattice results with continuum estimates.\nOur estimate of the pseudocritical temperature compares favorably with\ncontinuum results from staggered and domain wall fermions, confirming that a\ndynamical charm does not contribute in the transition region. From the high\ntemperature behaviour of the disconnected chiral susceptibility we infer the\ntopological susceptibility, which encodes relevant properties of the QCD axion,\na plausible Dark Matter candidate. The topological susceptibility thus measured\nexhibits a power-law decay for $T/T_c \\gtrsim 2$, with an exponent close to the\none predicted by the Dilute Instanton Gas Approximation (DIGA). Close to $T_c$\nthe temperature dependent effective exponent seems to approach the DIGA result\nfrom above, a behaviour which would support recent analytic calculations based\non an Instantons-dyons model. These results constrain the mass of a hypothetic\nQCD post-inflationary axion, once an assumption concerning the relative\ncontribution of axions to Dark Matter is made.",
        "positive": "Loop Representations of the Quark Determinant in Lattice QCD: The modelling of the ultraviolet contributions to the quark determinant in\nlattice QCD in terms of a small number of Wilson loops is examined. Complete\nDirac spectra are obtained for sizeable ensembles of SU(3) gauge fields at\n$\\beta$=5.7 on 6$^4$, 8$^4$, and 10$^4$ lattices allowing for the first time a\ndetailed study of the volume dependence of the effective loop action generating\nthe quark determinant. The connection to the hopping parameter expansion is\nexamined in the heavy quark limit. We compare the efficiency and accuracy of\nvarious methods- specifically, Lanczos versus stochastic approaches- for\nextracting the quark determinant on an ensemble of configurations."
    },
    {
        "anchor": "Pade approximants and g-2 for the muon: The leading hadronic contribution to the muon anomalous magnetic moment is\ngiven by a weighted euclidean momentum integral of the hadronic vacuum\npolarization. This integral is dominated by momenta of order the muon mass.\nSince in lattice QCD it is difficult to compute the vacuum polarization at a\nlarge number of low momenta, a parametrization of the vacuum polarization is\nrequired to extrapolate the data. Most fits to date are based on vector meson\ndominance, which introduces model dependence into the lattice computation of\nthe magnetic moment. Here we introduce a model-independent extrapolation\nmethod, and present a few first tests of this new method.",
        "positive": "On the spectrum of QCD-like theories and the conformal window: We report on the spectrum of the SU(3) gauge theory with twelve flavours in\nthe fundamental representation of the gauge group. We isolate distinctive\nfeatures of the hadronic phase - the one proper of QCD at zero temperature -\nand the so called conformal phase. The latter should emerge at sufficiently\nlarge Nf and before the loss of asymptotic freedom. In particular, we analyse\navailable lattice data for the spectrum of Nf=12 and include a comparison with\nresults with Nf=16; the latter theory, predicted by the perturbative\nbeta-function to develop an IRFP and therefore be in the conformal phase, can\nserve as a paradigm for the study of theories in the conformal window. Our\nanalysis suggests that the theory with twelve flavours is in the conformal\nwindow, possibly close to its lower boundary."
    },
    {
        "anchor": "Lattice Chiral Schwinger Model: Selected Results: We discuss a method for regularizing chiral gauge theories. The idea is to\nformulate the gauge fields on the lattice, while the fermion determinant is\nregularized and computed in the continuum. A simple effective action emerges\nwhich lends itself to numerical simulations.",
        "positive": "Quark Mass Dependence of the QCD Critical End Point in the Strong\n  Coupling Limit: Strong coupling lattice QCD in the dual representation allows to study the\nfull $\\mu$-$T$ phase diagram, due to the mildness of the finite density sign\nproblem. Such simulations have been performed in the chiral limit, both at\nfinite $N_t$ and in the continuous time limit. Here we extend the phase diagram\nto finite quark masses, with an emphasis on the low temperature first order\ntransition. We present our results on the quark mass dependence of the critical\nend point and the first order line obtained by Monte Carlo via the worm\nalgorithm."
    },
    {
        "anchor": "Scalar mesons in a finite volume: Using effective field theory methods, we discuss the extraction of the mass\nand width of the scalar mesons f0(980) and a0(980) from the finite-volume\nspectrum in lattice QCD. In particular, it is argued that the nature of these\nstates can be studied by invoking twisted boundary conditions, as well as\ninvestigating the quark mass dependence of the spectrum.",
        "positive": "Non-renormalization theorem in a lattice supersymmetric theory and the\n  cyclic Leibniz rule: N=4 supersymmetric quantum mechanical model is formulated on the lattice. Two\nsupercharges, among four, are exactly conserved with the help of the cyclic\nLeibniz rule without spoiling the locality. In use of the cohomological\nargument, any possible local terms of the effective action are classified into\ntwo categories which we call type-I and type-II, analogous to the D- and\nF-terms in the supersymmetric field theories. We prove non-renormalization\ntheorem on the type-II terms which include mass and interaction terms with\nkeeping a lattice constant finite, while type-I terms such as the kinetic terms\nhave nontrivial quantum corrections."
    },
    {
        "anchor": "Study of 1/m corrections in HQET: We report our exploratory study on the matching condition of HQET with QCD\nincluding 1/m corrections. We introduce a new observable from the dependence of\nthe heavy-light effective energy on the twisted boundary condition parameter\n$\\theta$, which could be used to match the kinetic term $\\vec{D}^2/(2m)$.\nCarrying out quenched QCD simulations for fixed lattice spacing in small\nvolumes with O(a)-improved Wilson fermions, we study the 1/m dependence of this\nobservable, from which the static limit and 1/m coefficient can be extracted.\nWe also compare our preliminary result with HQET.",
        "positive": "Monopole Percolation and The Universality Class of the Chiral Transition\n  in Four Flavor Noncompact Lattice QED: We simulate four flavor noncompact lattice QED using the Hybrid Monte Carlo\nalgorithm on $10^4$ and $16^4$ lattices. Measurements of the monopole\nsusceptibility and the percolation order parameter indicate a transition at\n$\\beta = {1/e^2} = .205(5)$ with critical behavior in the universality class of\nfour dimensional percolation. We present accurate chiral condensate\nmeasurements and monitor finite size effects carefully. The chiral condensate\ndata supports the existence of a power-law transition at $\\beta = .205$ in the\nsame universality class as the chiral transition in the two flavor model. The\nresulting equation of state predicts the mass ratio $m_\\pi^2/m_\\sigma^2$ in\ngood agreement with spectrum calculations while the hypothesis of a\nlogarithmically improved mean field theory fails qualitatively."
    },
    {
        "anchor": "Pseudoscalar decay constant in the heavy light systems: We discuss the size of the higher order terms in the NRQCD expansion of the\npseudoscalar decay constant. Power law divergences in the matrix elements\ncontributing to the pseudoscalar decay constant are also investigated.",
        "positive": "Coherent Topological Charge Structure in $CP^{N-1}$ Models and QCD: In an effort to clarify the significance of the recent observation of\nlong-range topological charge coherence in QCD gauge configurations, we study\nthe local topological charge distributions in two-dimensional $CP^{N-1}$ sigma\nmodels, using the overlap Dirac operator to construct the lattice topological\ncharge. We find long-range sign coherence of topological charge along extended\none-dimensional structures in two-dimensional spacetime. We discuss the\nconnection between the long range topological structure found in $CP^{N-1}$ and\nthe observed sign coherence along three-dimensional sheets in four-dimensional\nQCD gauge configurations. In both cases, coherent regions of topological charge\nform along membrane-like surfaces of codimension one. We show that the Monte\nCarlo results, for both two-dimensional and four-dimensional gauge theory,\nsupport a view of topological charge fluctuations suggested by Luscher and\nWitten. In this framework, the observed membranes are associated with\nboundaries between ``k-vacua,'' characterized by an effective local value of\n$\\theta$ which jumps by $\\pm 2\\pi$ across the boundary."
    },
    {
        "anchor": "GPUs: An Oasis in the Supercomputing Desert: A novel metric is introduced to compare the supercomputing resources\navailable to academic researchers on a national basis. Data from the\nsupercomputing Top 500 and the top 500 universities in the Academic Ranking of\nWorld Universities (ARWU) are combined to form the proposed \"500/500\" score for\na given country. Australia scores poorly in the 500/500 metric when compared\nwith other countries with a similar ARWU ranking, an indication that HPC-based\nresearchers in Australia are at a relative disadvantage with respect to their\noverseas competitors. For HPC problems where single precision is sufficient,\ncommodity GPUs provide a cost-effective means of quenching the computational\nthirst of otherwise parched Lattice practitioners traversing the Australian\nsupercomputing desert. We explore some of the more difficult terrain in single\nprecision territory, finding that BiCGStab is unreliable in single precision at\nlarge lattice sizes. We test the CGNE and CGNR forms of the conjugate gradient\nmethod on the normal equations. Both CGNE and a modified form of CGNR (with\nrestarts) provide reliable convergence for quark propagator calculations in\nsingle precision.",
        "positive": "Desperately Seeking Chiral Fermions: Chiral fermions can (presumably) be constructed by introducing two\nregulators, one for the gauge fields (e.g. a lattice), and another for the\nfermion functional integrals in a fixed (regulated) gauge field. This talk\ndiscusses cutoff effects arising from the regulator of the fermions."
    },
    {
        "anchor": "Towards the determination of the gluon helicity distribution in the\n  nucleon from lattice quantum chromodynamics: We present the first exploratory lattice quantum chromodynamics (QCD)\ncalculation of the polarized gluon Ioffe-time pseudo-distribution in the\nnucleon. The Ioffe-time pseudo-distribution provides a frame-independent and\ngauge-invariant framework to determine the gluon helicity in the nucleon from\nfirst principles. We employ a high-statistics computation using a $32^3\\times\n64$ lattice ensemble characterized by a $358$ MeV pion mass and a $0.094$ fm\nlattice spacing. We establish the pseudo-distribution approach as a feasible\nmethod to address the proton spin puzzle with successive improvements in\nstatistical and systematic uncertainties anticipated in the future. Within the\nstatistical precision of our data, we find a good comparison between the\nlattice determined polarized gluon Ioffe-time distribution and the\ncorresponding expectations from the state-of-the-art global analyses. We find a\nhint for a nonzero gluon spin contribution to the proton spin from the\nmodel-independent extraction of the gluon helicity pseudo-distribution over a\nrange of Ioffe-time, $\\nu\\lesssim 9$.",
        "positive": "Fermi point in graphene as a monopole in momentum space: We consider the effective field theory of graphene monolayer with the Coulomb\ninteraction between fermions taken into account. The gauge field in momentum\nspace is introduced. The position of the Fermi point coincides with the\nposition of the corresponding monopole. The procedure of extracting such\nmonopoles during lattice simulations is suggested."
    },
    {
        "anchor": "Duals of nonabelian gauge theories in $D$ dimensions: The dual of an arbitrary $D$-dimensional nonabelian lattice gauge theory,\nobtained after character expansion and integration over the gauge group, is\nshown to be a {\\em local} lattice theory in the eigenspace of the Casimir\noperators. For $D\\leq4$ we also provide the explicit form of the action as a\nproduct of character expansion coefficients and Racah coefficients. The\nrepresentation can be used to facilitate strong coupling expansions.\nFurthermore, the possibility of simulations, at weak coupling, in the dual\nrepresentation, is also discussed.",
        "positive": "Gluons in the lattice SU(2) classical field: The SU(2) gluonic correlation functions, glueball effective masses in the\n$J^{P}=0^{+}$, $2^{+}$ and $0^{-}$ channels were calculated from the lattice\nclassical gauge configurations which were obtained by smoothing the thermal\ngauge configurations through the improved cooling method. The instanton-induced\nattractive force in the $0^{+}$ channel and the repulsive force in the $0^-$\nchannel are confirmed in the Monte Carlo simulation. There is evidence that the\ninstanton vacuum contribution to the $0^+$ glueball mass is significant."
    },
    {
        "anchor": "Matrix product states and the nonabelian rotor model: We use uniform matrix product states (MPS) to study the (1+1)D $O(2)$ and\n$O(4)$ rotor models, which are equivalent to the Kogut-Susskind formulation of\nmatter-free nonabelian lattice gauge theory on a \"hawaiian earring\" graph for\n$U(1)$ and $SU(2)$, respectively. Applying tangent space methods to obtain\nground states and determine the mass gap and the $\\beta$ function, we find\nexcellent agreement with known results, locating the BKT transition for $O(2)$\nand successfully entering the asymptotic weak-coupling regime for $O(4)$. To\nobtain a finite local Hilbert space, we truncate in the space of generalized\nFourier modes of the gauge group, comparing the effects of different cutoff\nvalues. We find that higher modes become important in the crossover and\nweak-coupling regimes of the nonabelian theory, where entanglement also\nsuddenly increases. This could have important consequences for TNS studies of\nYang-Mills on higher dimensional graphs.",
        "positive": "Leading isospin breaking effects in the HVP contribution to $a_\u03bc$\n  and to the running of $\u03b1$: The anomalous magnetic moment of the muon $a_{\\mu}$ and the running of the\nelectromagnetic coupling $\\alpha$ play a fundamental role in beyond Standard\nModel (SM) physics searches. Non-perturbative hadronic contributions to both\nquantities, which are related to the hadronic vacuum polarization (HVP)\nfunction consisting of two electromagnetic currents, are a main source of\nuncertainty in the SM prediction. We compute the HVP function in lattice\nQCD+QED applying the time-momentum representation method. We expand the\nrelevant correlation functions around the isosymmetric limit. In particular, we\nfocus on leading isospin breaking effects taking quark-connected contributions\ninto account, which we evaluate on isosymmetric $N_{\\mathrm{f}}=2+1$ QCD gauge\nensembles generated by the CLS initiative with non-perturbatively\n$O(a)$-improved Wilson fermions."
    },
    {
        "anchor": "A disorder analysis of the Ising model: Lattice studies of monopole condensation in QCD are based on the construction\nof a disorder parameter, a creation operator of monopoles which is written in\nterms of the gauge fields. This procedure is expected to work for any system\nwhich presents duality. We check it on the Ising model in 2d, which is exactly\nsolvable. The output is an amusing exercise in statistical mechanics.",
        "positive": "Axial Nucleon form factors from lattice QCD: We present results on the nucleon axial form factors within lattice QCD using\ntwo flavors of degenerate twisted mass fermions. Volume effects are examined\nusing simulations at two volumes of spatial length $L=2.1$ fm and $L=2.8$ fm.\nCut-off effects are investigated using three different values of the lattice\nspacings, namely $a=0.089$ fm, $a=0.070$ fm and $a=0.056$ fm. The nucleon axial\ncharge is obtained in the continuum limit and chirally extrapolated to the\nphysical pion mass enabling comparison with experiment."
    },
    {
        "anchor": "Test of the Schr\u00f6dinger functional with chiral fermions in the\n  Gross-Neveu model: The recently proposed construction of chiral fermions on lattices with\nboundaries is tested in an interacting theory up to first order of perturbation\ntheory. We confirm that, in the bulk of the lattice, the chiral Ward identities\ntake their continuum value up to cutoff effects without any tuning. Universal\nquantities are defined that have an expansion in the renormalised couplings\nwith coefficients that are functions of the physical size and the periodicity\nin the spatial direction. These coefficient functions have to be identical for\ndifferent discretisations. We find agreement with the standard Wilson fermions.\nThe computation is done in the asymptotically free Gross-Neveu model with\ncontinuous chiral symmetry.",
        "positive": "$O(a^2)$-improved actions for heavy quarks and scaling studies on\n  quenched lattices: We investigate a new class of improved relativistic fermion action on the\nlattice with a criterion to give excellent energy-momentum dispersion relation\nas well as to be consistent with tree-level $O\\left(a^{2}\\right)$-improvement.\nMain application in mind is that for heavy quark for which $ma\\simeq O(0.5)$.\nWe present tree-level results and a scaling study on quenched lattices."
    },
    {
        "anchor": "Two-link Staggered Quark Smearing in QUDA: Gauge covariant smearing based on the 3D lattice Laplacian can be used to\ncreate extended operators that have better overlap with hadronic ground states.\nFor staggered quarks, we make use of two-link parallel transport to preserve\ntaste properties. We have implemented the procedure in QUDA. We present the\nperformance of this code on the NVIDIA A100 GPUs in Indiana University's Big\nRed 200 supercomputer and on the AMD MI250X GPUs in Oak Ridge Leadership\nComputer Facility's (OLCF's) Crusher and discuss its scalability. We also study\nthe performance improvement from using NVSHMEM on OLCF's Summit. Reusing\nprecomputed two-link products for all sources and sinks, it reduces the total\nsmearing time for a baryon correlator measurement by a factor of 100-120 as\ncompared with the original MILC code and reduces the overall time by 60-70%.",
        "positive": "Scalar field Restricted Boltzmann Machine as an ultraviolet regulator: Restricted Boltzmann Machines (RBMs) are well-known tools used in Machine\nLearning to learn probability distribution functions from data. We analyse RBMs\nwith scalar fields on the nodes from the perspective of lattice field theory.\nStarting with the simplest case of Gaussian fields, we show that the RBM acts\nas an ultraviolet regulator, with the cutoff determined by either the number of\nhidden nodes or a model mass parameter. We verify these ideas in the scalar\nfield case, where the target distribution is known, and explore implications\nfor cases where it is not known using the MNIST data set. We also demonstrate\nthat infrared modes are learnt quickest."
    },
    {
        "anchor": "The lattice gluon propagator in stochastic perturbation theory: We calculate loop contributions up to four loops to the Landau gauge gluon\npropagator in numerical stochastic perturbation theory. For different lattice\nvolumes we carefully extrapolate the Euler time step to zero for the Langevin\ndynamics derived from the Wilson action. The one-loop result for the gluon\npropagator is compared to the infinite volume limit of standard lattice\nperturbation theory.",
        "positive": "How the PHMC algorithm samples configuration space: We show that in practical simulations of lattice QCD with two dynamical light\nfermion species the PHMC algorithm samples configuration space differently from\nthe commonly used HMC algorithm."
    },
    {
        "anchor": "Scalar Glueball Decay: We evaluate the coupling constant for the lightest scalar glueball to decay\nto pseudoscalar meson pairs. The calculation is done in the valence\napproximation on a $16^3 \\times 24$ lattice at $\\beta = 5.70$ for two different\nvalues of pseudoscalar meson mass.",
        "positive": "Responses of hadrons to chemical potential at finite temperature: We present a framework to compute the responses of hadron masses to the\nchemical potential in lattice QCD simulations. As a first trial, the screening\nmass of the pseudoscalar meson and its first and second responses are\nevaluated. We present results on a $16\\times 8^2\\times 4$ lattice with two\nflavors of staggered quarks below and above $T_c$. The responses to both the\nisoscalar and isovector chemical potentials are obtained. They show different\nbehavior in the low and the high temperature phases, which may be explained as\na consequence of chiral symmetry breaking and restoration, respectively."
    },
    {
        "anchor": "QCD on 2+2 anisotropic lattices: We discuss the implementation of QCD on 2+2 anisotropic lattices. Technical\ndetails regarding the choice of the action as well as perturbative and\nnon-perturbative improvement are analyzed. The physical applications of the\nprogram are presented.",
        "positive": "Phase diagram of d=4 Ising Model with two couplings: We study the phase diagram of the four dimensional Ising model with first and\nsecond neighbour couplings, specially in the antiferromagnetic region, by using\nMean Field and Monte Carlo methods. From the later, all the transition lines\nseem to be first order except that between ferromagnetic and disordered phases\nin a region including the first-neighbour Ising transition point."
    },
    {
        "anchor": "Casimir effect for fermions on the lattice: The conventional Casimir effect has been studied in the continuous spacetime,\nbut to elucidate its counterpart in the lattice space is an important subject.\nHere, we discuss various types of Casimir effects for quantum fields on the\nlattice. By using a definition of the Casimir energy on the lattice, we show\nthat the Casimir effect for the Wilson fermion is similar to that for the\ncontinuous Dirac fermion. We apply our definition to an effective Hamiltonian\ndescribing Dirac semimetals, such as Cd$_{3}$As$_{2}$ and Na$_{3}$Bi, and find\nan oscillatory behavior of the Casimir energy as a function of film thickness\nof semimetals. We also study contributions from Landau levels under magnetic\nfields and the Casimir effect for nonrelativistic particle fields on the\nlattice.",
        "positive": "Universal scaling properties of QCD close to the chiral limit: We present a lattice QCD based determination of the chiral phase transition\ntemperature in QCD with two massless (up and down) and one strange quark having\nits physical mass. We propose and calculate two novel estimators for the chiral\ntransition temperature for several values of the light quark masses,\ncorresponding to Goldstone pion masses in the range of $58~{\\rm MeV}\\lesssim\nm_\\pi\\lesssim 163~{\\rm MeV}$. The chiral phase transition temperature is\ndetermined by extrapolating to vanishing pion mass using universal scaling\nrelations. After thermodynamic, continuum and chiral extrapolations we find the\nchiral phase transition temperature $T_c^0=132^{+3}_{-6}$ MeV. We also show\nsome preliminary calculations that use the conventional estimator for the\npseudo-critical temperature and compare with the new estimators for $T_c^0$.\nFurthermore, we show results for the ratio of the chiral order parameter and\nits susceptibility and argue that this ratio can be used to differentiate\nbetween $O(N)$ and $Z_2$ universality classes in a non-parametric manner."
    },
    {
        "anchor": "A non-perturbative determination of $b_{\\rm g}$: Close to the continuum limit, lattice QCD with mass-degenerate Wilson quarks\ncan be described by Symanzik's effective continuum action, which contains the\ndimension 5 operator, $m\\,{\\rm tr}(F_{\\mu\\nu}F_{\\mu\\nu})$. Its effect can be\neliminated by an O($am_{\\rm q}$) rescaling of the bare lattice coupling\nconstant. Until recently, the corresponding improvement coefficient, $b_{\\rm\ng}$, was only known perturbatively to 1-loop order and an estimate of the\nremaining uncertainty is the dominant systematic error in the ALPHA\ncollaboration's recent determination of $\\alpha_s(m_Z)$ with the decoupling\nmethod. To remove this error we have determined $b_{\\rm g}$ non-perturbatively\nfor the corresponding parameter range. We here briefly review improvement\nconditions for $b_{\\rm g}$, perform a perturbative test and report on our\nnon-perturbative results for $b_{\\rm g}$.",
        "positive": "Dressed Wilson loops as dual condensates in response to magnetic fields: We introduce dressed Wilson loops as a novel confinement observable. It\nconsists of closed planar loops of arbitrary geometry but fixed area and its\nexpectation values decay with the latter. The construction of dressed Wilson\nloops is based on chiral condensates in response to magnetic (and electric)\nfields, thus linking different physical concepts. We present results for\ngeneralized condensates and dressed Wilson loops on dynamical lattice\nconfigurations and confirm the agreement with conventional Wilson loops in the\nlimit of large probe mass. We comment on the renormalization of dressed Wilson\nloops."
    },
    {
        "anchor": "Genuine Symmetry of Staggered Fermion: We present a new formulation of the staggered fermion on the D-dimensional\nlattice based on the SO(2D) Clifford algebra, which is naturally present in the\naction. The action of the massless staggered fermion is invariant under the\ndiscrete rotation and the SO(2D) chiral and other discrete transformations.\n  From transformation properties of the fermion, we find two local meson\noperators (one scalar and one pseudoscalar) in addition to two standard meson\noperators.",
        "positive": "Critical behavior and monopole density in U(1) lattice gauge theory: Our study of the energy distribution has shown that the strength of the first\norder transition in the four-dimensional compact U(1) lattice gauge theory\ndecreases when the coupling $\\lambda$ of the monopole term increases. The\ndisappearance of the energy gap for sufficiently large values of $\\lambda$\nindicates that the transition ultimately becomes of second order. In our\npresent investigation, based on a finite-size analysis, we show that already at\n$\\lambda= 0.9$ the critical exponent is characteristic of a second-order\ntransition. Interestingly, this exponent turns out to be definitely different\nfrom that of the Gaussian case. We observe that the monopole density becomes\nconstant in the second order region. In addition we find the rather surprising\nresult that the phase transition persists up to very large values of $\\lambda$,\nwhere the transition moves to (large) negative $\\beta$."
    },
    {
        "anchor": "K\u00e4ll\u00e9n-Lehmann Spectral Representation of the Scalar SU(2) Glueball: The estimation of the K\\\"all\\'en-Lehmann spectral density from gauge\ninvariant lattice QCD two point correlation functions is proposed, and explored\nvia an appropriate inversion method. As proof of concept the SU(2) glueball\nspectrum for the quantum numbers $J^{PC} = 0^{++}$ is investigated for various\nvalues of the lattice spacing. The spectral density and the glueball spectrum\nare estimated using the published data of arXiv:1910.07756. Our estimates for\nthe ground state mass are in good agreement with the traditional approach\npublished therein, which is based on the large time exponential behaviour of\nthe correlation functions. Furthermore, the spectral density also contains\nhints of excites states in the spectrum.",
        "positive": "P-wave heavy-light mesons using NRQCD and D234: The masses of S- and P-wave heavy-light mesons are computed in quenched QCD\nusing a classically and tadpole-improved action on anisotropic lattices. Of\nparticular interest are the splittings among P-wave states, which have not yet\nbeen resolved experimentally; even the ordering of these states continues to be\ndiscussed in the literature. The present work leads to upper bounds for these\nsplittings, and is suggestive, but not conclusive, about the ordering."
    },
    {
        "anchor": "Electromagnetic corrections to the leptonic decay rates of charged\n  pseudoscalar mesons: lattice results: Electromagnetic effects in the leptonic decay rates $\\pi^+ \\to \\mu^+ \\nu$ and\n$K^+ \\to \\mu^+ \\nu$ are evaluated for the first time on the lattice. Following\na method recently proposed in Ref. [1] the emission of virtual photons at\nleading order in the electromagnetic coupling is evaluated on the lattice and\nthe infrared divergence computed for a point-like meson at finite lattice\nvolume is subtracted. The physical decay rate is then obtained by adding the\nemission of real and virtual photons regularised with a photon mass. Using the\ngauge ensembles produced by the European Twisted Mass Collaboration with $N_f =\n2 + 1 + 1$ dynamical quarks the feasibility of our approach is demonstrated.\nPreliminary results for the electromagnetic corrections to charged (neutral)\npion and kaon masses as well as to the leptonic decay rates of charged pions\nand kaons are presented.",
        "positive": "Towards leading isospin breaking effects in mesonic masses with open\n  boundaries: We present an exploratory study of leading isospin breaking effects in\nmesonic masses using $O(a)$ improved Wilson fermions with open boundaries.\nIsospin symmetry is explicitly broken by distinct masses and electric charges\nof the up and down quarks. In order to be able to make use of existing\nisosymmetric QCD gauge ensembles we apply reweighting techniques. The path\nintegral describing QCD+QED is expanded perturbatively in powers of deviations\nin the quark masses and the inverse strong coupling as well as the\nelectromagnetic coupling. We have constructed QED$_{\\mathrm{L}}$, which we use\nas a finite volume formulation of QED, for open boundaries. We will also give a\nfirst insight into contributions from quark disconnected diagrams."
    },
    {
        "anchor": "The Taming of QCD by Fortran 90: We implement lattice QCD using the Fortran 90 language. We have designed\nmachine independent modules that define fields (gauge, fermions, scalars,\netc...) and have defined overloaded operators for all possible operations\nbetween fields, matrices and numbers. With these modules it is very simple to\nwrite QCD programs. We have also created a useful compression standard for\nstoring the lattice configurations, a parallel implementation of the random\ngenerators, an assignment that does not require temporaries, and a machine\nindependent precision definition. We have tested our program on parallel and\nsingle processor supercomputers obtaining excellent performances.",
        "positive": "Probes of nearly conformal behavior in lattice simulations of minimal\n  walking technicolor: We present results from high precision, large volume simulations of the\nlattice gauge theory corresponding to minimal walking technicolor. We find\nevidence that the pion decay constant vanishes in the infinite volume limit and\nthat the dependence of the chiral condensate on quark mass m_q is inconsistent\nwith spontaneous symmetry breaking. These findings are consistent with the\nall-orders beta function prediction as well as the Schroedinger functional\nstudies that indicate the existence of a nontrivial infrared fixed point."
    },
    {
        "anchor": "Investigation of Doubly Heavy Tetraquark Systems using Lattice QCD: We search for possibly existent bound states in the heavy-light tetraquark\nchannels with quark content $ \\bar{b}\\bar{b}ud $, $ \\bar{b}\\bar{b}us $ and $\n\\bar{b}\\bar{c}ud $ using lattice QCD. We carry out calculations on several\ngauge link ensembles with $ N_f=2+1 $ flavours of domain-wall fermions and\nconsider a basis of local and non-local interpolators. Besides extracting the\nenergy spectrum from the correlation matrices, we also perform a L\\\"uscher\nanalysis to extrapolate our results to infinite volume.",
        "positive": "The Landau gauge lattice QCD simulation and the gluon propagator: The gluon propagator in the Landau gauge lattice QCD simulation of quenched\n8^3 x 16 lattice is measured. The data suggests the confinement mechanism of\nthe Gribov-Zwanziger theory."
    },
    {
        "anchor": "NSPT for $O(N)$ non-linear sigma model: the larger $N$ the better: The $O(N)$ non-linear sigma model (NLSM) is an example of field theory on a\ntarget space with nontrivial geometry. One interesting feature of NLSM is\nasymptotic freedom, which makes perturbative calculations interesting. Given\nthe successes in Lattice Gauge Theories, Numerical Stochastic Perturbation\nTheory (NSPT) is a natural candidate for performing high-order computations\nalso in the case of NLSM. However, in low-dimensional systems NSPT is known to\ndisplay statistical fluctuations substantially increasing for increasing\norders. In this work, we explore how for $O(N)$ NLSM this behaviour is strongly\ndependent on $N$. As largely expected on general grounds, the larger is $N$,\nthe larger is the order at which a NSPT computation can be effectively\nperformed.",
        "positive": "Non-perturbative O(a) improvement of lattice QCD: The coefficients multiplying the counterterms required for O($a$) improvement\nof the action and the isovector axial current in lattice QCD are computed\nnon-perturbatively, in the quenched approximation and for bare gauge couplings\n$g_0$ in the range $0 \\leq g_0 \\leq 1$. A finite-size method based on the\nSchr\\\"odinger functional is employed, which enables us to perform all\ncalculations at zero or nearly zero quark mass. As a by-product the critical\nhopping parameter $\\kappa_c$ is obtained at all couplings considered."
    },
    {
        "anchor": "Trace anomaly and dynamical quark mass: We investigated the origin of the RI'/MOM quark mass under the Landau gauge\nat the non-perturbative scale, using the chiral fermion with different quark\nmasses and lattice spacings. Our result confirms that such a mass is\nnon-vanishing based on the linear extrapolation to the chiral and continuum\nlimit, and shows that such a mass comes from the spontaneous chiral symmetry\nbreaking induced by the near zero modes with the eigenvalue $\\lambda<{\\cal\nO}(5m_q)$, and is proportional to the quark matrix element of the trace anomaly\nat least down to $\\sim $1.3 GeV.",
        "positive": "Matrix elements relevant for Delta I=1/2 rule and epsilon-prime from\n  Lattice QCD with staggered fermions: We perform a study of matrix elements relevant for the Delta I=1/2 rule and\nthe direct CP-violation parameter epsilon-prime from first principles by\ncomputer simulation in Lattice QCD. We use staggered (Kogut-Susskind) fermions,\nand employ the chiral perturbation theory method for studying K to 2 Pi decays.\nHaving obtained a reasonable statistical accuracy, we observe an enhancement of\nthe Delta I=1/2 amplitude, consistent with experiment within our large\nsystematic errors. Finite volume and quenching effects have been studied and\nwere found small compared to noise. The estimates of epsilon-prime are hindered\nby large uncertainties associated with operator matching. In this paper we\nexplain the simulation method, present the results and address the systematic\nuncertainties."
    },
    {
        "anchor": "Stable and quasi-stable confining SU(N) strings in D=2+1: We investigate the low-lying spectrum of closed confining flux-tubes that\nwind around a spatial torus in D=2+1 and carry flux in different\nrepresentations of SU(N). We focus on our most recent calculations for N=6 and\n{\\beta}=171, where the calculated low-energy physics is very close to the\ncontinuum and large-N limits. We investigate the adjoint, 84, 120, k = 2A, 2S\nand k = 3A, 3M, 3S representations and show that the corresponding flux-tubes\ndo exist. Similarly to the results for the fundamental representation, the\nground state of a flux-tube with momentum along its axis appears to be well\ndescribed by Nambu-Goto all the way down to very short tubes. In contrast,\nexcited states have much larger deviations from Nambu-Goto. We discuss whether\nthese states are non-string-like and associated with excitations of massive\nflux-tube modes.",
        "positive": "The Gribov problem and its solution from a toy model point of view: The standard Faddeev Popov gauge fixing procedure is put on solid grounds by\ntaking into account a topological factor which corrects for the number of\nGribov copies within the first Gribov horizon. Zwanziger's stochastic approach\nto gauge fixed Yang-Mills theory is briefly reviewed. A simple toy model is\npresented which illustrates both methods. Within the toy model, I show that a\nstochastic drift force can be constructed with which the gauged configurations\nare attracted by the fundamental modular region. The toy model shows that an\naction which gives rise to the drift force can be found. This makes a ``heat\nbath'' simulation possible, which is seen to be superior to the Langevin\napproach at the numerical level."
    },
    {
        "anchor": "Calculating the Isgur-Wise Function on the Lattice: We calculate the Isgur-Wise function by measuring the heavy-heavy meson\ntransition matrix element on the lattice. The standard Wilson action is used\nfor both the heavy and light quarks. Our first numerical results are presented.",
        "positive": "Low energy constants from the MILC Collaboration: Based on ongoing simulations, we update our results for low energy constants,\ndecay constants, and light quark masses. The simulations employ three dynamical\nflavors of improved staggered quarks."
    },
    {
        "anchor": "Bottomonium spectral widths at nonzero temperature using maximum\n  likelihood: We present progress results from the Fastsum collaboration's programme to\ndetermine the spectrum of the bottomonium system as a function of temperature\nusing a variety of approaches. In these proceedings, the Maximum Likelihood\napproach is used with an Ansatz comprising of a Gaussian spectral function for\nthe ground state. Fastsum anisotropic lattices with 2+1 dynamical quark\nflavours were used with temperatures ranging from 47 to 375 MeV.",
        "positive": "Continuum limit of lattice QCD with staggered quarks in the quenched\n  approximation - a critical role for the chiral extrapolation: We calculate the light quark spectrum of lattice QCD in the quenched\napproximation using Kogut-Susskind quarks. By combining results for different\nlattice spacings, several volumes and five quark masses, we are able to take\nthe light quark mass, infinite volume, continuum limit. When we use non-linear\nchiral extrapolations, we find that the nucleon to rho mass ratio is 1.254 +-\n0.018 +- 0.027, where the errors are statistical and systematic (within the\nquenched approximation), respectively. This should be compared with the\nexperimental value of 1.22. Our results indicate that the error due to\nquenching is less than about 5%."
    },
    {
        "anchor": "Lattice artefacts and the running of the coupling constant: We study the running of the L\\\"uscher-Weisz-Wolff (LWW) coupling constant in\nthe two dimensional O(3) nonlinear $\\sigma$ model. To investigate the continuum\nlimit we refine the lattice spacing from the $1\\over 16$ value used by LWW up\nto $1\\over 160$. We find that the lattice artefacts are much larger than\nestimated by LWW and that most likely the coupling constant runs slower than\npredicted by perturbation theory. A precise determination of the running in the\ncontinuum limit would require a controlled ansatz of extrapolation, which, we\nargue, is not presently available.",
        "positive": "The QCD chiral transition, $\\ua$ symmetry and the Dirac spectrum using\n  domain wall fermions: We report on a study of the finite-temperature QCD transition region for\ntemperatures between 139 and 196 MeV, with a pion mass of 200 MeV and two\nspace-time volumes: $24^3\\times8$ and $32^3\\times8$, where the larger volume\nvaries in linear size between 5.6 fm (at T=139 MeV) and 4.0 fm (at T=195 MeV).\nThese results are compared with the results of an earlier calculation using the\nsame action and quark masses but a smaller, $16^3\\times8$ volume. The chiral\ndomain wall fermion formulation with a combined Iwasaki and dislocation\nsuppressing determinant ratio gauge action are used. This lattice action\naccurately reproduces the $\\sua$ and $\\ua$ symmetries of the continuum. Results\nare reported for the chiral condensates, connected and disconnected\nsusceptibilities and the Dirac eigenvalue spectrum. We find a pseudo-critical\ntemperature, $T_c$, of approximately 165 MeV consistent with previous results\nand strong finite volume dependence below $T_c$. Clear evidence is seen for\n$\\ua$ symmetry breaking above $T_c$ which is quantitatively explained by the\nmeasured density of near-zero modes in accordance with the dilute instanton gas\napproximation."
    },
    {
        "anchor": "Quenched Finite Volume Logarithms: Quenched chiral perturbation theory is used to compute the first finite\nvolume correction to the chiral condensate. The correction diverges\nlogarithmically with the four-volume $V$. We point out that with dynamical\nquarks one can obtain both the chiral condensate and the pion decay constant\nfrom the distributions of the lowest Dirac operator eigenvalues.",
        "positive": "Perturbative and non-perturbative renormalization results of the\n  Chromomagnetic Operator on the Lattice: The Chromomagnetic operator (CMO) mixes with a large number of operators\nunder renormalization. We identify which operators can mix with the CMO, at the\nquantum level. Even in dimensional regularization (DR), which has the simplest\nmixing pattern, the CMO mixes with a total of 9 other operators, forming a\nbasis of dimension-five, Lorentz scalar operators with the same flavor content\nas the CMO. Among them, there are also gauge noninvariant operators; these are\nBRST invariant and vanish by the equations of motion, as required by\nrenormalization theory. On the other hand using a lattice regularization\nfurther operators with $d \\leq 5$ will mix; choosing the lattice action in a\nmanner as to preserve certain discrete symmetries, a minimul set of 3\nadditional operators (all with $d<5$) will appear. In order to compute all\nrelevant mixing coefficients, we calculate the quark-antiquark (2-pt) and the\nquark-antiquark-gluon (3-pt) Green's functions of the CMO at nonzero quark\nmasses. These calculations were performed in the continuum (dimensional\nregularization) and on the lattice using the maximally twisted mass fermion\naction and the Symanzik improved gluon action. In parallel, non-perturbative\nmeasurements of the $K-\\pi$ matrix element are being performed in simulations\nwith 4 dynamical ($N_f = 2+1+1$) twisted mass fermions and the Iwasaki improved\ngluon action."
    },
    {
        "anchor": "Scale r_0 and the static potential from the CLS lattices: We report on the measurement of the static potential and the scale r_0 from\nHYP-smeared Wilson loops in two flavour QCD. We analyse the quark mass\ndependence of the potential and r_0 at three lattice spacings. We also compare\nthe QCD static potential around distance r_0 with the static potential obtained\nfrom potential models.",
        "positive": "Lattice QCD computation of the SU(3) String Tension critical curve: We investigate the critical curve of the string tension sigma(T) as a\nfunction of temperature in quenched gauge invariant SU(3) lattice gauge theory.\nWe extract sigma(T) from the colour averaged free energy of a static\nquark-antiquark pair. To compute the free energy, we utilize a pair of gauge\ninvariant Polyakov loop and antiloop correlations, and apply the multihit\nprocedure to enhance the signal to noise ratio. We find that the string tension\ndeparts from the zero temperature sigma(0) at T close to 0.5 Tc. We cover the\nrelevant temperature range from 0.5 Tc up to the confinement temperature Tc\nusing 57 different sets of pure gauge lattice configurations with four temporal\nextensions (4,6,8,12), different beta and a spatial volume of 48^3 in lattice\nunits."
    },
    {
        "anchor": "Two Poisson structures invariant with respect to discrete transformation\n  in the case of arbitrary semi-simple algebras: Two Poisson structures invariant with respect to discrete transformation of\nthe Maximal root in the case of arbitrary semi-simple algebras are presented in\nexplicit form. Thus the problem of construction of equations of n-wave\nhierarchy in the case of arbitrary semi simple algebra is solved finally.",
        "positive": "Strong-coupling effective action(s) for SU(3) Yang-Mills: We apply strong-coupling expansion techniques to finite-temperature lattice\npure gauge theory, obtaining dimensionally reduced $Z_N$-symmetric effective\ntheories. The analytic mappings between the effective couplings and the\noriginal one, viz. $\\beta$, allow to estimate the transition point $\\beta_c$ of\nthe 4D theory for a large range of the imaginary-time extent $N_\\tau$ of the\nlattice. We study the models for SU(3) via Monte Carlo simulation, finding\nsatisfactory agreement with the critical point of the original theories\nespecially at low $N_\\tau$. We have fixed an error in the group measure used in\narXiv:1010.0951 and provide here the correct numerical results."
    },
    {
        "anchor": "Bottomonium above deconfinement in lattice nonrelativistic QCD: We study the temperature dependence of bottomonium for temperatures in the\nrange $0.4 T_c < T < 2.1 T_c$, using nonrelativistic dynamics for the bottom\nquark and full relativistic lattice QCD simulations for $N_f=2$ light flavors\non a highly anisotropic lattice. We find that the $\\Upsilon$ is insensitive to\nthe temperature in this range, while the $\\chi_b$ propagators show a crossover\nfrom the exponential decay characterizing the hadronic phase to a power-law\nbehaviour consistent with nearly-free dynamics at $T \\simeq 2 T_c$.",
        "positive": "Hamiltonian lattice QCD at finite chemical potential: At sufficiently high temperature and density, quantum chromodynamics (QCD) is\nexpected to undergo a phase transition from the confined phase to the\nquark-gluon plasma phase. In the Lagrangian lattice formulation the Monte Carlo\nmethod works well for QCD at finite temperature, however, it breaks down at\nfinite chemical potential. We develop a Hamiltonian approach to lattice QCD at\nfinite chemical potential and solve it in the case of free quarks and in the\nstrong coupling limit. At zero temperature, we calculate the vacuum energy,\nchiral condensate, quark number density and its susceptibility, as well as mass\nof the pseudoscalar, vector mesons and nucleon. We find that the chiral phase\ntransition is of first order, and the critical chemical potential is $\\mu_C\n=m_{dyn}^{(0)}$ (dynamical quark mass at $\\mu=0$). This is consistent with\n$\\mu_C \\approx M_N^{(0)}/3$ (where $M_N^{(0)}$ is the nucleon mass at $\\mu=0$)."
    },
    {
        "anchor": "Hadronic Coupling Constants in Lattice QCD: We calculate the hadronic coupling constants $g_{NN\\pi}$ and $g_{\\rho\\pi\\pi}$\nin QCD, including dynamical quarks in the framework of staggered fermions in\nthe lattice approach. For the nucleon--pion coupling we obtain $g_{NN\\pi} =\n13.8 \\pm 5.8$, to be compared with the experimental value $13.13 \\pm 0.07$. The\n$\\rho\\pi\\pi$ coupling has been analysed for two different sets of operators\nwith the averaged result $g_{\\rho\\pi\\pi} = 4.2 \\pm 1.9$ which is to be compared\nwith the experimental value $6.06 \\pm 0.01$.",
        "positive": "Quarkonium at non-zero isospin density: We calculate the energies of quarkonium bound states in the presence of a\nmedium of nonzero isospin density using lattice QCD. The medium, created using\na canonical (fixed isospin charge) approach, induces a reduction of the\nquarkonium energies. As the isospin density increases, the energy shifts first\nincrease and then saturate. The saturation occurs at an isospin density close\nto that where previously a qualitative change in the behaviour of the energy\ndensity of the medium has been observed, which was conjectured to correspond to\na transition from a pion gas to a Bose-Einstein condensed phase. The reduction\nof the quarkonium energies becomes more pronounced as the heavy-quark mass is\ndecreased, similar to the behaviour seen in two-colour QCD at non-zero quark\nchemical potential. In the process of our analysis, the $\\eta_b$-$\\pi$ and\n$\\Upsilon$-$\\pi$ scattering phase shifts are determined at low momentum. An\ninterpolation of the scattering lengths to the physical pion mass gives\n$a_{\\eta_b,\\pi} = 0.0025(8)(6)$ fm and $a_{\\Upsilon,\\pi} = 0.0030(9)(7)$ fm."
    },
    {
        "anchor": "An Analytic Variational Study of the Mass Spectrum in 2+1 Dimensional\n  SU(3) Hamiltonian Lattice Gauge Theory: We calculate the masses of the lowest lying eigenstates of improved SU(2) and\nSU(3) lattice gauge theory in 2+1 dimensions using an analytic variational\napproach. The ground state is approximated by a one plaquette trial state and\nmass gaps are calculated in the symmetric and antisymmetric sectors by\nminimising over a suitable basis of rectangular states.",
        "positive": "Taylor expansions on Lefschetz thimbles (and not only that): Thimble regularisation is a possible solution to the sign problem, which is\nevaded by formulating quantum field theories on manifolds where the imaginary\npart of the action stays constant (Lefschetz thimbles). A major obstacle is due\nto the fact that one in general needs to collect contributions coming from more\nthan one thimble. Here we explore the idea of performing Taylor expansions on\nLefschetz thimbles. We show that in some cases we can compute expansions in\nregions where only the dominant thimble contributes to the result in such a way\nthat these (different, disjoint) regions can be bridged. This can most\neffectively be done via Pad\\'e approximants. In this way multi-thimble\nsimulations can be circumvented. The approach can be trusted provided we can\nshow that the analytic continuation we are performing is a legitimate one,\nwhich thing we can indeed show. We briefly discuss two prototypal computations,\nfor which we obtained a very good control on the analytical structure (and\nsingularities) of the results. All in all, the main strategy that we adopt is\nsupposed to be valuable not only in the thimble approach, which thing we\nfinally discuss."
    },
    {
        "anchor": "Specific heat and energy for the three-dimensional O(2) model: We investigate the three-dimensional O(2) model on lattices of size 8^3 to\n160^3 close to the critical point at zero magnetic field. We confirm explicitly\nthe value of the critical coupling J_c found by Ballesteros et al. and estimate\nthere the universal values of g_r and xi/L. At the critical point we study the\nfinite size dependencies of the energy density epsilon and the specific heat C.\nWe find that the nonsingular part of the specific heat C_{ns} is linearly\ndependent on 1/alpha. From the critical behaviour of the specific heat for T\nnot T_c on the largest lattices we determine the universal amplitude ratio\nA+/A-. The alpha- dependence of this ratio is close to the phenomenological\nrelation A+/A- = 1-4alpha.",
        "positive": "From Loops to Surfaces: The generating function for all antisymmetric characters of a Wilson loop\nmatrix in SU(N) Yang Mills theory is the partition function of a fermion living\non the curve describing the loop. This generalizes to fermion subsystems living\non higher dimensional submanifolds, for example, surfaces. This write-up also\ncontains some extra background, in response to some questions raised during the\noral presentation."
    },
    {
        "anchor": "Status of dynamical ensemble generation: I give an overview of current and future plans of dynamical QCD ensemble\ngeneration activities. A comparison of simulation cost between different\ndiscretizations is made. Recent developments in techniques and algorithms used\nin QCD dynamical simulations, especially mass reweighting, are also discussed.",
        "positive": "Hadron Spectroscopy and Resonances: Review: I review recent results on hadron spectroscopy using lattice QCD. In light of\nthe discoveries in heavy baryon sector at LHCb over the past few years, lattice\ncalculations in this regard are emphasized. Investigations on light baryon,\nheavy-heavy and heavy-light meson resonances are also discussed."
    },
    {
        "anchor": "Layered Phase Investigations: The extra dimensional defects that are introduced to generate the lattice\nchiral zero modes are not simply a computational trick, but have interesting\nphysical consequences. After reviewing what is known about the layered phase\nthey can generate, I argue how it is possible to simulate Yang-Mills theories\nwith reduced systematic errors and speculate on how it might be possible to\nstudy the fluctuations of the layers' topological charge.",
        "positive": "Three-dimensional physics and the pressure of hot QCD: We update Monte Carlo simulations of the three-dimensional SU(3) + adjoint\nHiggs theory, by extrapolating carefully to the infinite volume and continuum\nlimits, in order to estimate the contribution of the infrared modes to the\npressure of hot QCD. The sum of infrared contributions beyond the known 4-loop\norder turns out to be a smooth function, of a reasonable magnitude and specific\nsign. Unfortunately, adding this function to the known 4-loop terms does not\nimprove the match to four-dimensional lattice data, in spite of the fact that\nother quantities, such as correlation lengths, spatial string tension, or quark\nnumber susceptibilities, work well within the same setup. We outline possible\nways to reduce the mismatch."
    },
    {
        "anchor": "A test of first order scaling in Nf =2 QCD: a progress report: We present the status of our analysis on the order of the finite temperature\ntransition in QCD with two flavors of degenerate fermions. Our new simulations\non large lattices support the hypothesis of the first order nature of the\ntransition, showing a preliminary two state signal. We will discuss the\nimplications and the next steps in our analysis.",
        "positive": "Towards the N_f=2 deconfinement transition temperature with O(a)\n  improved Wilson fermions: A lot of effort in lattice simulations over the last years has been devoted\nto studies of the QCD deconfinement transition. Most state-of-the-art\nsimulations use rooted staggered fermions, while Wilson fermions are affected\nby large systematic uncertainties, such as coarse lattices or heavy sea quarks.\nHere we report on an ongoing study of the transition, using two degenerate\nflavours of nonperturbatively $\\Ord(a)$ improved Wilson fermions. We start with\n$N_{t}=12$ and 16 lattices and pion masses of 600 to 450 MeV, aiming at chiral\nand continuum limits with light quarks."
    },
    {
        "anchor": "Constrained curve fitting for semi-parametric models with radial basis\n  function networks: Common to many analysis pipelines in lattice gauge theory and the broader\nscientific discipline is the need to fit a semi-parametric model to data. We\npropose a fit method that utilizes a radial basis function network to\napproximate the non-parametric component of such models. The approximate\nparametric model is fit to data using the basin hopping global optimization\nalgorithm. Parameter constraints are enforced through Gaussian priors. The\nviability of our method is tested by examining its use in a finite-size scaling\nanalysis of the $q$-state Potts model and $p$-state clock model with $q=2,3$\nand $p=4,\\infty$.",
        "positive": "Parton distribution functions on the lattice and in the continuum: Ioffe-time distributions, which are functions of the Ioffe-time $\\nu$, are\nthe Fourier transforms of parton distribution functions with respect to the\nmomentum fraction variable $x$. These distributions can be obtained from\nsuitable equal time, quark bilinear hadronic matrix elements which can be\ncalculated from first principles in lattice QCD, as it has been recently\nargued. In this talk I present the first numerical calculation of the\nIoffe-time distributions of the nucleon in the quenched approximation."
    },
    {
        "anchor": "Some continuum physics results from the lattice V-A correlator: We present preliminary results on extractions of the chiral LECs L_10 and\nC_87 and constraints on the excited pseudoscalar state pi(1300) and pi(1800)\ndecay constants obtained from an analysis of lattice data for the flavor ud\nlight quark V-A correlator. A comparison of the results for the correlator to\nthe corresponding mildly-model-dependent continuum results (based primarily on\nexperimental hadronic tau decay data) is also given",
        "positive": "Extended hadron and two-hadron operators of definite momentum for\n  spectrum calculations in lattice QCD: Multi-hadron operators are crucial for reliably extracting the masses of\nexcited states lying above multi-hadron thresholds in lattice QCD Monte Carlo\ncalculations. The construction of multi-hadron operators with significant\ncoupling to the lowest-lying multi-hadron states of interest involves combining\nsingle hadron operators of various momenta. The design and implementation of\nlarge sets of spatially-extended single-hadron operators of definite momentum\nand their combinations into two-hadron operators are described. The single\nhadron operators are all assemblages of gauge-covariantly-displaced, smeared\nquark fields. Group-theoretical projections onto the irreducible\nrepresentations of the symmetry group of a cubic spatial lattice are used in\nall isospin channels. Tests of these operators on 24^3 x 128 and 32^3 x 256\nanisotropic lattices using a stochastic method of treating the low-lying modes\nof quark propagation which exploits Laplacian Heaviside quark-field smearing\nare presented. The method provides reliable estimates of all needed\ncorrelations, even those that are particularly difficult to compute, such as\neta eta -> eta eta in the scalar channel, which involves the subtraction of a\nlarge vacuum expectation value. A new glueball operator is introduced, and the\nevaluation of the mixing of this glueball operator with a quark-antiquark\noperator, pi-pi, and eta-eta operators is shown to be feasible."
    },
    {
        "anchor": "The Higgs boson resonance width from a chiral Higgs-Yukawa model on the\n  lattice: The Higgs boson is a central part of the electroweak theory and is crucial to\ngenerate masses for quarks, leptons and the weak gauge bosons. We use a\n4-dimensional Euclidean lattice formulation of the Higgs-Yukawa sector of the\nelectroweak model to compute physical quantities in the path integral approach\nwhich is evaluated by means of Monte Carlo simulations thus allowing for fully\nnon perturbative calculations. The chiral symmetry of the model is incorporated\nby using the Neuberger overlap Dirac operator. The here considered Higgs-Yukawa\nmodel does not involve the weak gauge bosons and furthermore, only a degenerate\ndoublet of top- and bottom quarks are incorporated. The goal of this work is to\nstudy the resonance properties of the Higgs boson and its sensitivity to the\nstrength of the quartic self coupling.",
        "positive": "Wilson-like fermions and the static B_B parameter with no chirality\n  breaking mixings: I consider the recent proposal by R. Frezzotti and G. Rossi to chirally\nimprove Wilson fermions in such a way that mixings among operators of different\nchirality can be excluded. The method, which is based on the use of twisted\nmass QCD with several replica of valence quarks, is extended here to\nstatic-light systems. The operators relevant for the computation of the B_B\nparameter (in the static approximation) are discussed. In this case the same\nrenormalization pattern as for Ginsparg-Wilson fermions is obtained by a simple\nmodification of the discretization of the action for valence quarks."
    },
    {
        "anchor": "Avoiding the sign-problem in lattice field theory: In lattice field theory, the interactions of elementary particles can be\ncomputed via high-dimensional integrals. Markov-chain Monte Carlo (MCMC)\nmethods based on importance sampling are normally efficient to solve most of\nthese integrals. But these methods give large errors for oscillatory\nintegrands, exhibiting the so-called sign-problem. We developed new quadrature\nrules using the symmetry of the considered systems to avoid the sign-problem in\nphysical one-dimensional models for the resulting high-dimensional integrals.\nThis article gives a short introduction to integrals used in lattice QCD where\nthe interactions of gluon and quark elementary particles are investigated,\nexplains the alternative integration methods we developed and shows results of\napplying them to models with one physical dimension. The new quadrature rules\navoid the sign-problem and can therefore be used to perform simulations at\nuntil now not reachable regions in parameter space, where the MCMC errors are\ntoo big for affordable sample sizes. However, it is still a challenge to\ndevelop these techniques further for applications with physical\nhigher-dimensional systems.",
        "positive": "Ising string beyond Nambu-Goto: A major result of the Effective String Theory (EST) description of\nconfinement is the so called \"low energy universality,\" which states that the\nfirst few terms of the large distance expansion of any EST are universal and\ncoincide with those of the Nambu-Goto action. Going beyond this approximation\nis one of the most interesting open problems in the EST. In the higher order\nterms beyond Nambu-Goto several important pieces of physical information are\nencoded, which could improve our understanding of the physical mechanisms\nbehind confinement and of the physical degrees of freedoms which originate the\nEST. In this paper we evaluate numerically the first two of these corrections\nin the case of the three dimensional gauge Ising model. The first of them turns\nout to be negative: $\\gamma_3=-0.00048(4)$, similar (but not equal) to the one\nrecently measured in the $SU(2)$ Yang Mills theory in three dimensions and\ncompatible with the bootstrap bound $\\gamma_3 \\geq -\\frac{1}{768}$."
    },
    {
        "anchor": "What lattice theorists can do for superstring/M-theory: The gauge/gravity duality provides us with nonperturbative formulation of\nsuperstring/M-theory. Although inputs from gauge theory side are crucial for\nanswering many deep questions associated with quantum gravitational aspects of\nsuperstring/M-theory, many of the important problems have evaded analytic\napproaches. For them, lattice gauge theory is the only hope at this moment. In\nthis review I give a list of such problems, putting emphasis on problems within\nreach in a five-year span, including both Euclidean and real-time simulations.",
        "positive": "A Monte Carlo algorithm for simulating fermions on Lefschetz thimbles: A possible solution of the notorious sign problem preventing direct Monte\nCarlo calculations for systems with non-zero chemical potential is to deform\nthe integration region in the complex plane to a Lefschetz thimble. We\ninvestigate this approach for a simple fermionic model. We introduce an easy to\nimplement Monte Carlo algorithm to sample the dominant thimble. Our algorithm\nrelies only on the integration of the gradient flow in the numerically stable\ndirection, which gives it a distinct advantage over the other proposed\nalgorithms. We demonstrate the stability and efficiency of the algorithm by\napplying it to an exactly solvable fermionic model and compare our results with\nthe analytical ones. We report a very good agreement for a certain region in\nthe parameter space where the dominant contribution comes from a single\nthimble, including a region where standard methods suffer from a severe sign\nproblem. However, we find that there are also regions in the parameter space\nwhere the contribution from multiple thimbles is important, even in the\ncontinuum limit."
    },
    {
        "anchor": "Quantum Geometry and Diffusion: We study the diffusion equation in two-dimensional quantum gravity, and show\nthat the spectral dimension is two despite the fact that the intrinsic\nHausdorff dimension of the ensemble of two-dimensional geometries is very\ndifferent from two. We determine the scaling properties of the quantum gravity\naveraged diffusion kernel.",
        "positive": "Precision study of critical slowing down in lattice simulations of the\n  CP^{N-1} model: With the aim of studying the relevance and properties of critical slowing\ndown in Monte Carlo simulations of lattice quantum field theories we carried\nout a high precision numerical study of the discretised two-dimensional\nCP^{N-1} model at N=10 using an over-heat bath algorithm. We identify critical\nslowing down in terms of slowly-evolving topological modes and present evidence\nthat other observables couple to these slow modes. This coupling is found to\nreduce however as we increase the physical volume in which we simulate."
    },
    {
        "anchor": "Chiral symmetry at finite T, the phase of the Polyakov loop and the\n  spectrum of the Dirac operator: A recent Monte Carlo study of {\\em quenched} QCD showed that the chiral\ncondensate is non-vanishing above $T_c$ in the phase where the average of the\nPolyakov loop $P$ is complex. We show how this is related to the dependence of\nthe spectrum of the Dirac operator on the boundary conditions in Euclidean\ntime. We use a random matrix model to calculate the density of small\neigenvalues and the chiral condensate as a function of $\\arg P$. The chiral\nsymmetry is restored in the $\\arg P=2\\pi/3$ phase at a higher $T$ than in the\n$\\arg P=0$ phase. In the phase $\\arg P = \\pi$ of the $SU(2)$ gauge theory the\nchiral condensate stays nonzero for all~$T$.",
        "positive": "Spontaneous symmetry breaking on the lattice generated by Yukawa\n  interaction: We study by numerical simulation a lattice Yukawa model with naive fermions\nat intermediate values of the Yukawa coupling $y$ when the nearest neighbour\ncoupling $\\kp$ of the scalar field $\\Phi$ is very weakly ferromagnetic ($\\kp\n\\approx 0$) or even antiferromagnetic ($\\kappa < 0$) and the nonvanishing value\nof $\\vev$ is generated by the Yukawa interaction. The renormalized Yukawa\ncoupling $y_R$ achieves here its maximal value and this $y$-region is thus of\nparticular importance for lattice investigations of strong Yukawa interaction.\nHowever, here the scalar field propagators have a very complex structure caused\nby fermion loop corrections and by the proximity of phases with\nantiferromagnetic properties. We develop methods for analyzing these\npropagators and for extracting the physical observables. We find that going\ninto the negative $\\kp$ region, the scalar field renormalization constant\nbecomes small and $y_R$ does not seem to exceed the unitarity bound, making the\nexistence of a nontrivial fixed point in the investigated Yukawa model quite\nunlikely."
    },
    {
        "anchor": "Mass anomalous dimension of Adjoint QCD at large N from twisted volume\n  reduction: In this work we consider the $SU(N)$ gauge theory with two Dirac fermions in\nthe adjoint representation, in the limit of large $N$. In this limit the\ninfinite-volume physics of this model can be studied by means of the\ncorresponding twisted reduced model defined on a single site lattice. Making\nuse of this strategy we study the reduced model for various values of $N$ up to\n289. By analyzing the eigenvalue distribution of the adjoint Dirac operator we\ntest the conformality of the theory and extract the corresponding mass\nanomalous dimension.",
        "positive": "Entanglement entropy from non-equilibrium lattice simulations: Entanglement entropy encodes important features of strongly interacting\nquantum many-body systems and gauge theories, but its analytical study is still\nlimited to systems with high level of symmetry. This motivates the search for\nefficient techniques to investigate this quantity numerically, through Monte\nCarlo calculations on the lattice. In this contribution, we discuss the\ncomputation of the entropic c-function by means of an algorithm based on\nJarzynski's equality, which is an exact theorem from non equilibrium\nstatistical mechanics. After presenting benchmark results for the Ising model\nin two dimensions, where our algorithm successfully reproduces the analytical\npredictions from conformal field theory, we discuss its generalization to the\nthree-dimensional Ising model, for which we were able to extract universal\nterms beyond the area law. Finally we point out some future generalizations of\nthis calculation."
    },
    {
        "anchor": "Study of SU(3) vortex-like configurations with a new maximal center\n  gauge fixing method: We present a new way of fixing the gauge to (direct) maximal center gauge in\nSU(N) Yang-Mills theory and apply this method to SU(3) configurations which are\nvortex-like. We study the structure of the Z_3 configurations obtained after\ncenter-projecting the SU(3) ones.",
        "positive": "Chiral Perturbation Theory for Staggered Sea Quarks and Ginsparg-Wilson\n  Valence Quarks: We study lattice QCD with staggered sea and Ginsparg-Wilson valence quarks.\nThe Symanzik effective action for this mixed lattice theory, including the\nlattice spacing contributions of O(a^2), is derived. Using this effective\ntheory we construct the leading order chiral Lagrangian. The masses and decay\nconstants of pseudoscalars containing two Ginsparg-Wilson valence quarks are\ncomputed at one loop order."
    },
    {
        "anchor": "Physics at Tevatron Run II: We present recent physics results from the Tevatron Collider experiments CDF\nand D0. (contribution to Lattice 2004)",
        "positive": "Lattice QCD at finite temperature: Evidence for calorons from the\n  eigenvectors of the Dirac operator: We analyze the eigenvalues and eigenvectors of the staggered Dirac operator\nin quenched lattice QCD in the vicinity of the deconfinement phase transition\nusing the L\\\"uscher-Weisz gauge action. The spectral and localization\nproperties of the low-lying eigenmodes show characteristic differences between\nthe Z_3 sectors above the critical temperature T_c. These findings can be\ninterpreted in terms of calorons."
    },
    {
        "anchor": "Charm spectroscopy on dynamical 2+1 flavor domain wall fermion lattices\n  with a relativistic heavy quark action: We present a preliminary calculation of the charmonium spectrum using the\ndynamical 2+1 flavor $24^3\\times 64$ domain wall fermion lattice configurations\ngenerated by the RBC and UKQCD collaborations. We use the relativistic heavy\nquark action with 3 parameters non-perturbatively determined by matching to\nexperimental quantities. Chiral extrapolation is done on four light sea quark\nmasses from 0.005 to 0.03, with $m_s=0.04$ and $m_{res}=0.003$. We can either\npredict meson masses assuming the lattice spacing is known from other methods,\nor calculate the lattice spacing using those quantities.",
        "positive": "The pion-nucleon sigma term from Lattice QCD: We summarize recent evidence, both from lattice QCD and chiral perturbation\ntheory, that suggests that larger-than-expected excited-state contamination\ncould be the reason for the tension between phenomenological determinations and\nprevious direct lattice-QCD calculations of the pion--nucleon sigma term\n$\\sigma_{\\pi N}$. In addition, we extend the $\\chi$PT analysis by calculating\nthe corrections due to including the $\\Delta(1232)$ resonance as an explicit\ndegree of freedom. This correction is found to be small, thereby corroborating\nthe excited-state effects found in the $\\Delta$-less calculation and the result\nfor $\\sigma_{\\pi N}$."
    },
    {
        "anchor": "Studying the gradient flow coupling in the Schr\u00f6dinger functional: We discuss the setup and features of a new definition of the running coupling\nin the Schr\\\"odinger functional scheme based on the gradient flow. Its\nsuitability for a precise continuum limit in QCD is demonstrated on a set of\nNf=2 gauge field ensembles in a physical volume of L~0.4fm.",
        "positive": "On the efficient numerical solution of lattice systems with low-order\n  couplings: We apply the Quasi Monte Carlo (QMC) and recursive numerical integration\nmethods to evaluate the Euclidean, discretized time path-integral for the\nquantum mechanical anharmonic oscillator and a topological quantum mechanical\nrotor model. For the anharmonic oscillator both methods outperform standard\nMarkov Chain Monte Carlo methods and show a significantly improved error\nscaling. For the quantum mechanical rotor we could, however, not find a\nsuccessful way employing QMC. On the other hand, the recursive numerical\nintegration method works extremely well for this model and shows an at least\nexponentially fast error scaling."
    },
    {
        "anchor": "High precision Monte Carlo simulations of interfaces in the\n  three-dimensional Ising model: a comparison with the Nambu-Goto effective\n  string model: Motivated by the recent progress in the effective string description of the\ninterquark potential in lattice gauge theory, we study interfaces with periodic\nboundary conditions in the three-dimensional Ising model. Our Monte Carlo\nresults for the associated free energy are compared with the next-to-leading\norder (NLO) approximation of the Nambu-Goto string model. We find clear\nevidence for the validity of the effective string model at the level of the NLO\ntruncation.",
        "positive": "Lattice QCD Calculation of the Pion Mass Splitting: We use the infinite volume reconstruction method to calculate the\ncharged/neutral pion mass difference. The hadronic tensor is calculated on\nlattice QCD and then combined with an analytic photon propagator, and the mass\nsplitting is calculated with exponentially-suppressed finite volume errors. The\ncalculation is performed using six gauge ensembles generated with $2+1$-flavor\ndomain wall fermions, and five ensembles are at the physical pion mass. Both\nFeynman and Coulomb gauge are adopted in the calculation and result in a good\nagreement when the lattice spacing approaches zero. After performing the\ncontinuum extrapolation and examining the residual finite-volume effects, we\nobtain the pion mass splitting $\\Delta m_\\pi = 4.534(42)(43)~\\mathrm{MeV}$,\nwhich agrees well with experimental measurements."
    },
    {
        "anchor": "The Thermal Width of the Glueball at Non-Zero Temperature: We use SU(3) anisotropic lattice QCD at quenched level to study the 0++\nglueball correlator at various temperature taking into account the possible\nexistence of the thermal width in the ground-state peak. For this purpose, we\nadopt the Breit-Wigner ansatz for the appropriate fit-function for the lattice\ndata obtained with 5,500-9,900 gauge configurations at each T. The results show\nthe significant thermal width broadening as Gamma(T_c) \\sim 300 MeV with a\nreduction in the peak center as Delta omega_0(T_c) \\sim 100 MeV near the\ncritical temperature T_c.",
        "positive": "Properties of Color-Coulomb String Tension: We study the properties of the color-Coulomb string tension obtained from the\ninstantaneous part of gluon propagators in Coulomb gauge using quenched SU(3)\nlattice simulation.\n  In the confinement phase, the dependence of the color-Coulomb string tension\non the QCD coupling constant is smaller than that of the Wilson loop string\ntension. On the other hand, in the deconfinement phase, the color-Coulomb\nstring tension does not vanish even for $T/T_c = 1 \\sim 5$, the temperature\ndependence of which is comparable with the magnetic scaling, dominating the\nhigh temperature QCD. Thus, the color-Coulomb string tension is not an order\nparameter of QGP phase transition."
    },
    {
        "anchor": "Deformed matrix models, supersymmetric lattice twists and N=1/4\n  supersymmetry: A manifestly supersymmetric nonperturbative matrix regularization for a\ntwisted version of N=(8,8) theory on a curved background (a two-sphere) is\nconstructed. Both continuum and the matrix regularization respect four exact\nscalar supersymmetries under a twisted version of the supersymmetry algebra. We\nthen discuss a succinct Q=1 deformed matrix model regularization of N=4 SYM in\nd=4, which is equivalent to a non-commutative $A_4^*$ orbifold lattice\nformulation. Motivated by recent progress in supersymmetric lattices, we also\npropose a N=1/4 supersymmetry preserving deformation of N=4 SYM theory on\n$\\R^4$. In this class of N=1/4 theories, both the regularized and continuum\ntheory respect the same set of (scalar) supersymmetry. By using the equivalence\nof the deformed matrix models with the lattice formulations, we give a very\nsimple physical argument on why the exact lattice supersymmetry must be a\nsubset of scalar subalgebra. This argument disagrees with the recent claims of\nthe link approach, for which we give a new interpretation.",
        "positive": "Bayesian Analysis of Many-Pole Fits of Hadron Propagators in Lattice QCD: We use Bayes' probability theorem to analyze many-pole fits of hadron\npropagators. An alternative method of estimating values and uncertainties of\nthe fit parameters is offered, which has certain advantages over the\nconventional methods. The probability distribution of the parameters of a fit\nis calculated. The relative probability of various models is calculated."
    },
    {
        "anchor": "Lattice QCD with Domain Decomposition on Intel Xeon Phi Co-Processors: The gap between the cost of moving data and the cost of computing continues\nto grow, making it ever harder to design iterative solvers on extreme-scale\narchitectures. This problem can be alleviated by alternative algorithms that\nreduce the amount of data movement. We investigate this in the context of\nLattice Quantum Chromodynamics and implement such an alternative solver\nalgorithm, based on domain decomposition, on Intel Xeon Phi co-processor (KNC)\nclusters. We demonstrate close-to-linear on-chip scaling to all 60 cores of the\nKNC. With a mix of single- and half-precision the domain-decomposition method\nsustains 400-500 Gflop/s per chip. Compared to an optimized KNC implementation\nof a standard solver [1], our full multi-node domain-decomposition solver\nstrong-scales to more nodes and reduces the time-to-solution by a factor of 5.",
        "positive": "Measure of Autocorrelation Times of Local Hybrid Monte Carlo Algorithm\n  for Lattice QCD: We report on a study of the autocorrelation times of the local version of the\nHybrid Monte Carlo (LHMC) algorithm for pure gauge $SU(3)$. We compare LHMC to\nstandard multi-hit Metropolis and to the global version of the same HMC. For\nevery algorithm we measure the autocorrelation time for a variety of\nobservables and the string tension as a function of beta. The measurements\nperformed on 8^4 and 16^4 lattices indicate that the autocorrelation time of\nLHMC is significantly shorter than for the other two algorithms."
    },
    {
        "anchor": "Vortex Content of SU(2) Calorons and Multi-Calorons: We use Laplacian Center Gauge to reveal the vortex content of single SU(2)\ncalorons and multi-caloron systems at different holonomies. The vortex surfaces\nin a single SU(2) caloron consist of two parts that are induced by the\nconstituent dyon charges and by the twist between the dyons, respectively. The\nlatter part percolates in a caloron ensemble at maximal nontrivial holonomy.\nThis finding fits perfectly in the confinement scenario of vortices and shows\nthat calorons are suitable to facilitate the vortex confinement mechanism.",
        "positive": "Exact results for supersymmetric quantum mechanics on the lattice: We discuss N=2 supersymmetric quantum mechanics on the lattice using the\nfermion loop formulation. In this approach the system naturally decomposes into\na bosonic and fermionic sector. This allows us to deal with the sign problem\narising in the context of broken supersymmetry due to the vanishing of the\nWitten index. Employing transfer matrix techniques we obtain exact results at\nfinite lattice spacing and are hence able to study how the continuum limit is\napproached. In particular, we determine how supersymmetry is restored and how,\nin the case of broken supersymmetry, the goldstino mode emerges."
    },
    {
        "anchor": "QCD Thermodynamics on the Lattice from the Gradient Flow: To obtain the precise values of the bulk quantities and transport\ncoefficients in quark-gluon-plasma phase, we propose that a direct calculation\nof the renormalized energy-momentum tensor (EMT) on the lattice using the\ngradient flow. From one-point function of EMT, authors in Ref.[1] obtained the\ninteraction measure and thermal entropy. The results are consistent with the\none obtained by the integral method. Based on the success, we try to measure\nthe two-point function of EMT, which is related to the transport coefficients.\nAdvantages of our method are (1) a clear signal because of the smearing effects\nof the gradient flow and (2) no need to calculate the wave function\nrenormalization of EMT. In addition, we give a short remark on a comparison of\nthe numerical cost between the positive- and adjoint-flow methods for fermions,\nneeded to obtain the EMT in the (2+1) flavor QCD.",
        "positive": "$\u03b1_S$ from Lattice QCD: progresses and perspectives for a realistic\n  full-QCD determination of the running Strong coupling: Some very recent computations of $\\alpha_{\\bar{\\rm MS}}(M_Z)$ from $N_f=1+1$\nlattice simulations and of the running of the Strong coupling, obtained from\nthe lattice ghost-gluon vertex, over a large momentum window are very briefly\nreviewed."
    },
    {
        "anchor": "Form factors in lattice QCD: Lattice simulations of QCD have produced precise estimates for the masses of\nthe lowest-lying hadrons which show excellent agreement with experiment. By\ncontrast, lattice results for the vector and axial vector form factors of the\nnucleon show significant deviations from their experimental determination. We\npresent results from our ongoing project to compute a variety of form factors\nwith control over all systematic uncertainties. In the case of the pion\nelectromagnetic form factor we employ partially twisted boundary conditions to\nextract the pion charge radius directly from the linear slope of the form\nfactor near vanishing momentum transfer. In the nucleon sector we focus\nspecifically on the possible contamination from contributions of higher excited\nstates. We argue that summed correlation functions offer the possibility of\neliminating this source of systematic error. As an illustration of the method\nwe discuss our results for the axial charge, gA, of the nucleon.",
        "positive": "A generalized Ginsparg-Wilson relation: We show that, under certain general assumptions, any sensible lattice Dirac\noperator satisfies a generalized form of the Ginsparg-Wilson relation (GWR).\nThose assumptions, on the other hand, are mostly dictated by large momentum\nbehaviour considerations. We also show that all the desirable properties often\ndeduced from the standard GWR hold true of the general case as well; hence one\nhas, in fact, more freedom to modify the form of the lattice Dirac operator,\nwithout spoiling its nice properties. Our construction, a generalized\nGinsparg-Wilson relation (GGWR), is satisfied by some known proposals for the\nlattice Dirac operator. We discuss some of these examples, and also present a\nderivation of the GGWR in terms of a renormalization group transformation with\na blocking which is not diagonal in momentum space, but nevertheless commutes\nwith the Dirac operator."
    },
    {
        "anchor": "Vortex topology and the continuum limit of lattice gauge theories: We study the stability of Z_2 topological vortex excitations in d+1\ndimensional SU(2) Yang-Mills theory on the lattice at T=0. This is found to\ndepend on d and on the coupling considered. We discuss the connection with\nlattice artifacts causing bulk transitions in the beta_A-beta_F plane and draw\nsome conclusions regarding the continuum limit of the theory.",
        "positive": "A Universal Fractal Structure of 2D Quantum Gravity for c > 1: We investigate the fractal structure of $2d$ quantum gravity coupled to\nmatter by measuring the distributions of so-called baby universes. We\ndemonstrate that the method works well as long as $c \\leq 1$. For $c >1$ it is\nnot clear what distribution to expect. However, we observe strikingly similar\ndistributions for various kinds of matter fields with the same $c$. This\nindicate that there might be some range of $c >1$ where the central charge of\nthe matter fields alone determines the fractal structure of gravity coupled to\nmatter. The hypothesis that the string susceptibility $\\g = 1/3$ is found to be\ncompatible with the data for $1 < c \\leq 4$."
    },
    {
        "anchor": "Recent Developments in Lattice QCD: I review the current status of lattice QCD results. I concentrate on new\nanalytical developments and on numerical results relevant to phenomenology.",
        "positive": "Screening of light mesons and charmonia at high temperature: We present lattice QCD results for the screening masses of light mesons and\ncharmonia. The lattice computations were performed with 2+1 flavors of improved\nstaggered quarks using quark masses which correspond to realistic pion and kaon\nmasses at zero temperature. For the light quark sector we have found that the\nscreening masses in the pseudo-scalar and the isovector scalar channels do not\nbecome degenerate at the chiral crossover temperature indicating an effective\nnon-restoration of the axial symmetry. Also the splitting between the vector\nand the pseudo-scalar screening masses persists even in the limit of zero\nlattice spacing and at a moderately high temperature around 420 MeV. In the\ncharmonium sector our investigation shows that the screening masses of the\npseudo-scalar and the vector charmonia are almost (within a few percent) equal\nto their zero temperature masses for temperatures less than 300 MeV. We also\npresent results for the charmonium screening masses using periodic boundary\nconditions along the temporal direction and discuss their implications."
    },
    {
        "anchor": "Density, short-range order and the quark-gluon plasma: We study the thermal part of the energy density spatial correlator in the\nquark-gluon plasma. We describe its qualitative form at high temperatures. We\nthen calculate it out to distances approx. 1.5/T in SU(3) gauge theory lattice\nsimulations for the range of temperatures 0.9<= T/T_c<= 2.2. The\nvacuum-subtracted correlator exhibits non-monotonic behavior, and is almost\nconformal by 2T_c. Its broad maximum at r approx. 0.6/T suggests a dense medium\nwith only weak short-range order, similar to a non-relativistic fluid near the\nliquid-gas phase transition, where eta/s is minimal.",
        "positive": "Singly and Doubly Charmed J=1/2 Baryon Spectrum from Lattice QCD: We compute the masses of the singly and doubly charmed baryons in full QCD\nusing the relativistic Fermilab action for the charm quark. For the light\nquarks we use domain-wall fermions in the valence sector and improved\nKogut-Susskind sea quarks. We use the low-lying charmonium spectrum to tune our\nheavy-quark action and as a guide to understanding the discretization errors\nassociated with the heavy quark. Our results are in good agreement with\nexperiment within our systematics. For the \\Xi_{cc}, we find the\nisospin-averaged mass to be M_{\\Xi_{cc}} = 3665 +/- 17 +/- 14 +0 -78 MeV; the\nthree given uncertainties are statistical, systematic and an estimate of\nlattice discretization errors, respectively. In addition, we predict the mass\nsplitting of the (isospin-averaged) spin-1/2 \\Omega_{cc} with the \\Xi_{cc} to\nbe M_{\\Omega_{cc}} - M_{\\Xi_{cc}} = 98 +/- 9 +/- 22 +/- 13 MeV (in this mass\nsplitting, the leading discretization errors are also suppressed by SU(3)\nsymmetry). Combining this splitting with our determination of M_{\\Xi_{cc}}\nleads to our prediction of the spin-1/2 \\Omega_{cc} mass, M_{\\Omega_{cc}} =\n3763 +/- 19 +/- 26 +13 -79 MeV."
    },
    {
        "anchor": "Investigating vector boson scattering: A fully gauge-invariant study: Vector boson scattering (VBS) plays a central role in the search for new\nphysics at collider experiments such as ATLAS and CMS at the LHC. Usually\npredictions for this kind of process are obtained using mainly perturbative\napproaches in fixed gauges. Here we present a fully gauge-invariant study of\nVBS in the scalar-channel involving three different types of Higgs-like\nparticles characterized by their mass; above (heavy), inside (resonance) or\nbelow (stable) the elastic region. To this end, we combine results obtained in\na reduced SM setup from (augmented) perturbation theory with those from\nnon-perturbative lattice simulations.",
        "positive": "Casimir scaling and renormalization of Polyakov loops in large-N gauge\n  theories: We study Casimir scaling and renormalization properties of Polyakov loops in\ndifferent irreducible representations in SU(N) gauge theories; in particular,\nwe investigate the approach to the large-N limit, by performing lattice\nsimulations of Yang-Mills theories with an increasing number of colors, from 2\nto 6. We consider the twelve lowest irreducible representations for each gauge\ngroup, and find strong numerical evidence for nearly perfect Casimir scaling of\nthe bare Polyakov loops in the deconfined phase. Then we discuss the\ntemperature dependence of renormalized loops, which is found to be\nqualitatively and quantitatively very similar for the various gauge groups. In\nparticular, close to the deconfinement transition, the renormalized Polyakov\nloop increases with the temperature, and its logarithm reveals a characteristic\ndependence on the inverse of the square of the temperature. At higher\ntemperatures, the renormalized Polyakov loop overshoots one, reaches a maximum,\nand then starts decreasing, in agreement with weak-coupling predictions. The\nimplications of these findings are discussed."
    },
    {
        "anchor": "QCD bulk thermodynamics and conserved charge fluctuations with HISQ\n  fermions: After briefly reviewing recent progress by the HotQCD collaboration in\nstudying the 2+1 flavor QCD equation of state, we will focus on results on\nfluctuations of conserved charges by the BNL-Bielefeld and HotQCD\ncollaborations. Higher order cumulants of the net-charge distributions are\nincreasingly dominated by a universal scaling behavior, which arises due to a\ncritical point of QCD in the chiral limit. Considering cumulants up to the\n6^{th} order, we observe that they generically behave as expected from\nuniversal scaling laws, which is quite different from cumulants calculated\nwithin the hadron resonance gas model. Taking ratios of these cumulants, we\nobtain volume independent results that can be compared to the experimental\nmeasurements. We will argue that the freeze-out chemical potentials and the\nfreeze-out temperature, usually obtained by a HRG model fit to the measured\nhadronic yields, can also be obtained in a model independent way from ab-initio\nlattice QCD calculations by utilizing observables related to conserved charge\nfluctuations. Further, we will show that the freeze-out strangeness and\nelectric charge chemical potentials can be fixed by imposing strangeness\nneutrality and isospin asymmetry constraints in the lattice QCD calculations,\nin order to accommodate conditions met in heavy ion collisions. All results\nhave been obtained with the highly improved staggered quark action (HISQ) and\nalmost physical quark masses on lattices with temporal extent of\nN_\\tau=6,8,10,12.",
        "positive": "From Doubled Chern-Simons-Maxwell Lattice Gauge Theory to Extensions of\n  the Toric Code: We regularize compact and non-compact Abelian Chern-Simons-Maxwell theories\non a spatial lattice using the Hamiltonian formulation. We consider a doubled\ntheory with gauge fields living on a lattice and its dual lattice. The Hilbert\nspace of the theory is a product of local Hilbert spaces, each associated with\na link and the corresponding dual link. The two electric field operators\nassociated with the link-pair do not commute. In the non-compact case with\ngauge group $\\mathbb{R}$, each local Hilbert space is analogous to the one of a\ncharged \"particle\" moving in the link-pair group space $\\mathbb{R}^2$ in a\nconstant \"magnetic\" background field. In the compact case, the link-pair group\nspace is a torus $U(1)^2$ threaded by $k$ units of quantized \"magnetic\" flux,\nwith $k$ being the level of the Chern-Simons theory. The holonomies of the\ntorus $U(1)^2$ give rise to two self-adjoint extension parameters, which form\ntwo non-dynamical background lattice gauge fields that explicitly break the\nmanifest gauge symmetry from $U(1)$ to $\\mathbb{Z}(k)$. The local Hilbert space\nof a link-pair then decomposes into representations of a magnetic translation\ngroup. In the pure Chern-Simons limit of a large \"photon\" mass, this results in\na $\\mathbb{Z}(k)$-symmetric variant of Kitaev's toric code, self-adjointly\nextended by the two non-dynamical background lattice gauge fields. Electric\ncharges on the original lattice and on the dual lattice obey mutually anyonic\nstatistics with the statistics angle $\\frac{2 \\pi}{k}$. Non-Abelian $U(k)$\nBerry gauge fields that arise from the self-adjoint extension parameters may be\ninteresting in the context of quantum information processing."
    },
    {
        "anchor": "Dynamically-coupled partial-waves in $\u03c1\u03c0$ isospin-2 scattering from\n  lattice QCD: We present the first determination of $\\rho \\pi$ scattering, incorporating\ndynamically-coupled partial-waves, using lattice QCD, a first-principles\nnumerical approach to QCD. Considering the case of isospin-2 $\\rho \\pi$, we\ncalculate partial-wave amplitudes with $J \\le 3$ and determine the degree of\ndynamical mixing between the coupled $S$ and $D$-wave channels with $J^P=1^+$.\nThe analysis makes use of the relationship between scattering amplitudes and\nthe discrete spectrum of states in the finite volume lattice. Constraints on\nthe scattering amplitudes are provided by over one hundred energy levels\ncomputed on two lattice volumes at various overall momenta and in several\nirreducible representations of the relevant symmetry groups. The spectra follow\nfrom variational analyses of matrices of correlations functions computed with\nlarge bases of meson-meson operators. Calculations are performed with\ndegenerate light and strange quarks tuned to the physical strange quark mass so\nthat $m_\\pi \\sim 700$ MeV, ensuring that the $\\rho$ is stable against strong\ndecay. This work demonstrates the successful application of techniques, opening\nthe door to calculations of scattering processes that incorporate the effects\nof dynamically-coupled partial-waves, including those involving resonances or\nbound states.",
        "positive": "New perspectives on the emergence of (3+1)D expanding space-time in the\n  Lorentzian type IIB matrix model: The type IIB matrix model is a promising candidate for a nonperturbative\nformulation of superstring theory. In the Lorentzian version, in particular,\nthe emergence of (3+1)D expanding space-time was observed by Monte Carlo\nstudies of this model. Here we provide new perspectives on the (3+1)D expanding\nspace-time that have arised from recent studies. First it was found that the\nmatrix configurations generated by the simulation are singular in that the\nsubmatrices representing the expanding 3D space have only two large eigenvalues\nassociated with the Pauli matrices. This problem was conjectured to occur due\nto the approximation used to avoid the sign problem in simulating the model. In\norder to confirm this conjecture, the complex Langevin method was applied to\novercome the sign problem instead of using the approximation. The results\nindeed showed a clear departure from the Pauli-matrix structure, while the\n(3+1)D expanding behavior remained unaltered. It was also found that classical\nsolutions obtained within a certain ansatz show quite generically a (3+1)D\nexpanding behavior with smooth space-time structure."
    },
    {
        "anchor": "Parity doubling in two-flavor SU(2) at high temperature: We study the mass spectrum of mesons at high temperature in $SU(2)$ gauge\ntheory with two flavors of Dirac fundamental fermions. Numerical simulations\nare carried out on anisotropic lattices using Wilson fermions, with lattice\nparameters tuned so that Euclidean symmetry is restored at low energy. We\ndetermine the pseudo-critical temperature $T_c$ using renormalized Polyakov\nloops. We calculate temporal and spatial meson correlation functions across\n$T_c$, and observe a clear sign of parity doublings above $T_c$ in both vector\nand scalar channels. The degeneracy between parity partners in the spectrum\nindicates that the enhanced $SU(4) \\times U(1)_A$ global symmetry of the model\nis restored at high temperature.",
        "positive": "Fortran MPI Checkerboard Code for SU(3) Lattice Gauge Theory I: We document Fortran MPI checkerboard code for Markov Chain Monte Carlo\nsimulations of pure SU(3) lattice gauge theory with the Wilson action on a\nD-dimensional double-layered torus. This includes the usual torus with periodic\nboundary conditions as an optional case. We use Cabibbo-Marinari heatbath\ncheckerboard updating. Parallelization on sublattices is implemented in all D\ndirections and can be restricted to less than D directions. The parallelization\ntechniques of this paper can be used for any model with interactions of link\nvariables defined on plaquettes."
    },
    {
        "anchor": "Lattice Dirac Fermions on a Simplicial Riemannian Manifold: The lattice Dirac equation is formulated on a simplicial complex which\napproximates a smooth Riemann manifold by introducing a lattice vierbein on\neach site and a lattice spin connection on each link. Care is taken so the\nconstruction applies to any smooth D-dimensional Riemannian manifold that\npermits a spin connection. It is tested numerically in 2D for the projective\nsphere ${\\mathbb S}^2$ in the limit of an increasingly refined sequence of\ntriangles. The eigenspectrum and eigenvectors are shown to converge rapidly to\nthe exact result in the continuum limit. In addition comparison is made with\nthe continuum Ising conformal field theory on ${\\mathbb S}^2$. Convergence is\ntested for the two point, $\\langle \\epsilon(x_1) \\epsilon(x_2) \\rangle$, and\nthe four point, $\\langle \\sigma(x_1) \\epsilon(x_2) \\epsilon(x_3 )\\sigma(x_4)\n\\rangle $, correlators for the energy, $\\epsilon(x) = i \\bar \\psi(x)\\psi(x)$,\nand twist operators, $\\sigma(x)$, respectively.",
        "positive": "Leptonic widths of heavy quarkonia: QCD/NRQCD matching for the\n  electromagnetic current at O(\u03b1_s v^2): We construct the S-wave part of the electromagnetic vector annihilation\ncurrent to $O(\\alpha_s v^2)$, where $v$ is the non-relativistic quark velocity,\nfor heavy quarks whose dynamics are described by the NRQCD action on the\nlattice. The NRQCD vector current for $Q\\bar{Q}$ annihilation is expressed as a\nlinear combination of lattice operators with quantum numbers L=0, $J^P=1^-$,\nand the coefficients are determined by matching to the corresponding continuum\ncurrent in QCD to$O(v^2)$ at one-loop. The annihilation channel gives a complex\namplitude with Coulomb-exchange and infrared singularities, making a careful\nchoice for the contours of integration and infrared subtraction functions in\nthe numerical integration necessary. An automated vertex generation program\nwritten in Python is employed, allowing us to use a realistic NRQCD action and\nan improved gluon lattice action; a change in the definition of either action\nis easily accommodated in this procedure. The final result is applicable to\nsimulations of electromagnetic decays of heavy quarkonia, notably the\n$\\Upsilon$ meson."
    },
    {
        "anchor": "SU(4) pure-gauge phase structure and string tensions: We present numerical evidence that the SU(4) pure-gauge dynamics has a\nfinite-temperature first-order phase transition. For a $6\\times 20^3$ lattice,\nthis transition occurs at the inverse-square coupling of $8/g^2 \\sim 10.79$.\nBelow this and above the known bulk phase transition at $8/g^2 \\sim 10.2$ is a\nconfined phase in which we find two different string tensions, one between the\nfundamental 4 and $4^*$ representations and the other between the self-dual\ndiquark 6 representations. The ratio of these two is about 1.5. The correlation\nin the adjoint representation suggests no string forms between adjoint charges.",
        "positive": "Nucleon axial charge from quenched lattice QCD with domain wall fermions\n  and DBW2 gauge action: The domain wall fermion (DWF) method, with its almost perfectly preserved\nchiral symmetry on the lattice, makes the calculation of the nucleon axial\ncharge particularly easy. By maintaining chiral symmetry and using the\nWard-Takahashi (WT) identity, one has Z_A = Z_V and the bare lattice\ncalculation yields the physical value without explicit renormalization. The\nDBW2 improved gauge action provides further enhancement of the symmetry and\nhence a more accurate WT identity at coarse lattice spacing. Taking advantage\nof these methods, we confirmed a significant volume dependence of the nucleon\naxial charge on (1.2 fm)^3 and (2.4 fm)^3 lattice volumes."
    },
    {
        "anchor": "The scaling functions of the free energy density and its derivatives for\n  the 3d O(4) model: We derive direct representations of the scaling functions of the 3d O(4)\nmodel which are relevant for comparisons to other models, in particular QCD.\nThis is done in terms of expansions in the scaling variable z= t/h^{1/Delta}.\nThe expansions around z=0 and the corresponding asymptotic ones for z --> +-\ninfinity overlap such that no interpolation is needed. The expansion\ncoefficients are determined numerically from the data of a previous high\nstatistics simulation of the O(4) model on a three-dimensional lattice of\nlinear extension L=120. From the scaling function of the magnetization we\ncalculate the leading asymptotic coefficients of the scaling function of the\nfree energy density. As a result we obtain the universal amplitude ratio\nA^+/A^-=1.84(4) for the specific heat. Comparing the scaling function of the\nenergy density to the data we find the non-singular part of the energy density\nepsilon_{ns}(T) with high precision and at the same time excellent scaling\nproperties.",
        "positive": "Strings and Branes in Nonabelian Gauge Theory: It is an old speculation that SU(N) gauge theory can alternatively be\nformulated as a string theory. Recently this subject has been revived, in the\nwake of the discovery of D-branes. In particular, it has been argued that at\nleast some conformally invariant cousins of the theory have such a string\nrepresentation. This is a pedagogical introduction to these developments for\nnon-string theorists. Some of the existing arguments are simplified."
    },
    {
        "anchor": "The Non-Perturbative ${\\cal O}(g^6)$ Contribution to the Free Energy of\n  Hot SU(N) Gauge Theory: The non-perturbative input necessary for the determination of the ${\\cal\nO}(g^6)$ part of the weak coupling expansion of the free energy density for\nSU(2) and SU(3) gauge theories is estimated. Although the perturbative\ninformation completing the contribution to this order is missing, we give\narguments that the magnetic fluctuations are dominated by screened elementary\nmagnetic gluons.",
        "positive": "Relevant momentum components of gluons for confinement and chiral\n  symmetry breaking: We investigate which momentum components of gluons induce color confinement\nand spontaneous chiral symmetry breaking in lattice QCD. For this purpose, we\nformulate a lattice framework to introduce the momentum cutoff of the gluon\nfield. Using this framework, we calculate the quark-antiquark potential, the\ncolor flux tube, the chiral condensate, and the Dirac spectrum. Our results\nsuggest that confinement and chiral symmetry breaking are induced by somehow\ndifferent momentum components of gluons."
    },
    {
        "anchor": "Deconfinement in Yang-Mills: a conjecture for a general gauge Lie group\n  G: Svetitsky and Yaffe have argued that -- if the deconfinement phase transition\nof a (d+1)-dimensional Yang-Mills theory with gauge group G is second order --\nit should be in the universality class of a d-dimensional scalar model\nsymmetric under the center C(G) of G. These arguments have been investigated\nnumerically only considering Yang-Mills theory with gauge symmetry in the\nG=SU(N) branch, where C(G)=Z(N). The symplectic groups Sp(N) provide another\nextension of SU(2)=Sp(1) to general N and they all have the same center Z(2).\nHence, in contrast to the SU(N) case, Sp(N) Yang-Mills theory allows to study\nthe relevance of the group size on the order of the deconfinement phase\ntransition keeping the available universality class fixed. Using lattice\nsimulations, we present numerical results for the deconfinement phase\ntransition in Sp(2) and Sp(3) Yang-Mills theories both in (2+1)d and (3+1)d. We\nthen make a conjecture on the order of the deconfinement phase transition in\nYang-Mills theories with general Lie groups SU(N), SO(N), Sp(N) and with\nexceptional groups G(2), F(4), E(6), E(7), E(8). Numerical results for G(2)\nYang-Mills theory at finite temperature in (3+1)d are also presented.",
        "positive": "Mass Gap, Abelian Dominance and Vortex Dynamics in SU(2) Spin Model: We discuss a new approach to the investigation of the nature of the mass gap\nin spin systems with continuous global symmetries which is much analogous to\nthe method of abelian projection in the gauge theories. We suggest that the\nabelian degrees of freedom, in particular, abelian vortices are responsible for\nthe mass gap generation phenomena in the non-abelian spin systems. To check our\nhypothesis we study numerically the three-dimensional SU(2) spin model in the\nMaximal Abelian projection. We find that the abelian mass gap in the projected\ntheory coincides with the full non-abelian mass gap within numerical errors.\nThe study of the percolation properties of the abelian vortex trajectories\nshows that the phase transition and the mass gap generation in the 3D SU(2)\nspin model are driven by the abelian vortex condensation."
    },
    {
        "anchor": "Finite Temperature Lattice QCD with Clover Fermions: We report on our simulation of finite temperature lattice QCD with two\nflavors of ${\\cal O}(a)$ Symanzik-improved fermions and ${\\cal O}(a^2)$\nSymanzik-improved glue. Our thermodynamic simulations were performed on an $8^3\n\\times 4$ lattice, and we have performed complementary zero temperature\nsimulations on an $8^3 \\times 16$ lattice. We compare our results to those from\nsimulations with two flavors of Wilson fermions and discuss the improvement\nresulting from use of the improved action.",
        "positive": "Dynamics of Clusters in Two-dimensional Potts Model: Dynamical behavior of the clusters during relaxation is studied in\ntwo-dimensional Potts model using cluster algorithm. Average cluster size and\ncluster formation velocity are calculated on two different lattice sizes for\ndifferent number of states during initial stages of the Monte Carlo simulation.\nDependence of these quantities on the order of the transition provides an\nefficient method to study nature of the phase transitions occuring in similar\nmodels."
    },
    {
        "anchor": "Implementation of Simultaneous Inversion of a Multi-shifted Dirac Matrix\n  for Twisted-Mass Fermions within DD-\u03b1AMG: At physical light quark masses, efficient linear solvers are crucial for\ncarrying out the millions of inversions of the Dirac matrix required for\nobtaining high statistics in quark correlation functions. Adaptive algebraic\nmulti-grid methods have proven to be very efficient in such cases, exhibiting\nmild critical slowing down towards very light quark masses and outperforming\ntraditional solver methods, such as the conjugate gradient method, at the\nphysical point. We will discuss our implementations of simultaneous inversion\nof a (degenerate) Dirac matrix for twisted-mass fermions for multiple\nright-hand-sides (rhs) with multi-shifts and block-Krylov solvers. The\nimplementation is carried out within the community library DD$\\alpha$AMG, which\nimplements aggregation-based Domain Decomposition adaptive algebraic multi-grid\nmethods. The block-Krylov solvers are provided via the Fast Accurate Block\nLinear krylOv Solver (Fabulous) library and can be used at coarser levels. Our\ncode inverts Dirac matrices with different twisted-mass terms and for multiple\nrhs simultaneously and is thus also suitable for components within a typical\nlattice QCD simulation workflow, such as the rational approximation. We show\npreliminary results on scalability and compare the performance of our\nimplementation when using different Block-Krylov solver techniques.",
        "positive": "Nucleon Excited States in N$_f$=2 lattice QCD: We investigate the excited states of the nucleon using $N_f=2$ twisted mass\ngauge configurations with pion masses in the range of about 270 MeV to 450 MeV\nand one ensemble of $N_f=2$ Clover fermions at almost physical pion mass. We\nuse two different sets of variational bases and study the resulting generalized\neigenvalue problem. We present results for the two lowest positive and negative\nparity states."
    },
    {
        "anchor": "Hyperon vector coupling f_1(0) from 2+1 flavor lattice QCD: We present results for the hyperon vector form factor f_1 for $\\Xi^0\n\\rightarrow \\Sigma^+ l\\bar{\\nu}$ and $\\Sigma^- \\rightarrow n l\\bar{\\nu}$\nsemileptonic decays from dynamical lattice QCD with domain-wall quarks.\nSimulations are performed on the 2+1 flavor gauge configurations generated by\nthe RBC and UKQCD Collaborations with a lattice cutoff of 1/a = 1.7 GeV. Our\npreliminary results, which are calculated at the lightest sea quark mass (pion\nmass down to approximately 330 MeV), show that a sign of the second-order\ncorrection of SU(3) breaking on hyperon vector coupling f_1(0) is likely\nnegative.",
        "positive": "Phase structure of U(1) lattice gauge theory with monopole term: We investigate four-dimensional compact U(1) lattice gauge theory with a\nmonopole term added to the Wilson action. First we consider the phase structure\nat negative $\\beta$, revealing some properties of a third phase region there,\nin particular the existence of a number of different states. Then our present\nstudies concentrate on larger values of the monopole coupling $\\lambda$ where\nthe confinement-Coulomb phase transition turns out to become of second order.\nPerforming a finite-size analysis we find that the critical exponent $\\nu$ is\nclose to, however, different from the gaussian value and that in the range\nconsidered $\\nu$ increases somewhat with $\\lambda$."
    },
    {
        "anchor": "Blockspin renormalization-group study of color confinement due to\n  violation of the non-Abelian Bianchi identity: Block-spin transformation of topological defects is applied to the violation\nof the non-Abelian Bianchi identity (VMABI) on lattice defined as Abelian\nmonopoles. To get rid of lattice artifacts, we introduce various techniques\nsmoothing the vacuum. The effective action can be determined by adopting the\ninverse Monte-Carlo method. The coupling constants $F(i)$ of the effective\naction depend on the coupling of the lattice action $\\beta$ and the number of\nthe blocking step $n$. But it is found that $F(i)$ satisfy a beautiful scaling,\nthat is, they are a function of the product $b=na(\\beta)$ alone for lattice\ncoupling constants $3.0\\le\\beta\\le3.9$ and the steps of blocking $1\\le n\\le\n12$. The effective action showing the scaling behavior can be regarded as an\nalmost perfect action corresponding to the continuum limit, since $a\\to 0$ as\n$n\\to\\infty$ for fixed $b$. The almost perfect action showing the scaling is\nfound to be independent of the smooth gauges adopted here. Then we compare the\nresults with those obtained by the analytic blocking method of topological\ndefects from the continuum. The infrared monopole action can be transformed\ninto that of the string model. The physical string tension and the lowest\nglueball mass can be evaluated \\textit{analytically} by the strong-coupling\nexpansion of the string model. We get $\\sqrt{\\sigma}\\simeq\n1.3\\sqrt{\\sigma_{phys}}$ for $b\\ge 1.0\\ \\ (\\sigma_{phys}^{-1/2})$, whereas the\nscalar glueball mass is kept to be near $M(0^{++})\\sim\n3.7\\sqrt{\\sigma_{phys}}$. Also we can almost reproduce \\textit{analytically}\nthe scaling function of the squared monopole density determined numerically for\nlarge $b$ region $b>1.2\\ (\\sigma_{phys}^{-1/2})$.",
        "positive": "The strange and light quark contributions to the nucleon mass from\n  Lattice QCD: We determine the strangeness and light quark fractions of the nucleon mass by\ncomputing the quark line connected and disconnected contributions to the matrix\nelements m_q <N|qbar q|N> in lattice QCD, using the non-perturbatively improved\nSheikholeslami-Wohlert Wilson Fermionic action. We simulate n_F=2 mass\ndegenerate sea quarks with a pion mass of about 285 MeV and a lattice spacing a\napprox 0.073 fm. The renormalization of the matrix elements involves mixing\nbetween contributions from different quark flavours. The pion-nucleon\nsigma-term is extrapolated to physical quark masses exploiting the sea quark\nmass dependence of the nucleon mass. We obtain the renormalized values\n\\sigma_{\\pi N} = 38(12) MeV at the physical point and f_{T_s}=\\sigma_s/m_N=\n0.012(14)^{+10}_{-3} for the strangeness contribution at our larger than\nphysical sea quark mass."
    },
    {
        "anchor": "Flavour breaking effects in the pseudoscalar meson decay constants: The SU(3) flavour symmetry breaking expansion in up, down and strange quark\nmasses is extended from hadron masses to meson decay constants. This allows a\ndetermination of the ratio of kaon to pion decay constants in QCD. Furthermore\nwhen using partially quenched valence quarks the expansion is such that SU(2)\nisospin breaking effects can also be determined. It is found that the lowest\norder SU(3) flavour symmetry breaking expansion (or Gell-Mann-Okubo expansion)\nworks very well. Simulations are performed for 2+1 flavours of clover fermions\nat four lattice spacings.",
        "positive": "Complex Langevin dynamics for dynamical QCD at nonzero chemical\n  potential: a comparison with multi-parameter reweighting: We study lattice QCD at non-vanishing chemical potential using the complex\nLangevin equation. We compare the results with multi-parameter reweighting both\nfrom $\\mu=0$ and phase quenched ensembles. We find a good agreement for lattice\nspacings below $\\approx$0.15 fm. On coarser lattices the complex Langevin\napproach breaks down. Four flavors of staggered fermions are used on $N_t=4, 6$\nand 8 lattices. For one ensemble we also use two flavors to investigate the\neffects of rooting."
    },
    {
        "anchor": "Skewness, kurtosis and the 5th and 6th order cumulants of net\n  baryon-number distributions from lattice QCD confront high-statistics STAR\n  data: We present new results on up to $6^{th}$ order cumulants of net baryon-number\nfluctuations at small values of the baryon chemical potential, $\\mu_B$,\nobtained in lattice QCD calculations with physical values of light and strange\nquark masses. Representation of the Taylor expansions of higher order cumulants\nin terms of the ratio of the two lowest order cumulants,\n$M_B/\\sigma_B^2=\\chi_1^B(T,\\mu_B)/\\chi_2^B(T,\\mu_B)$, allows for a parameter\nfree comparison with data on net proton-number cumulants obtained by the STAR\nCollaboration in the Beam Energy Scan at RHIC. We show that recent high\nstatistics data on skewness and kurtosis ratios of net proton-number\ndistributions, obtained at beam energy $\\sqrt{s_{_{NN}}}=54.4$ GeV, agree well\nwith lattice QCD results on cumulants of net baryon-number fluctuations close\nto the pseudo-critical temperature, $T_{pc}(\\mu_B)$, for the chiral transition\nin QCD. We also present first results from a next-to-leading order expansion of\n$5^{th}$ and $6^{th}$ order cumulants on the line of pseudo-critical\ntemperatures.",
        "positive": "The $\u039b(1405)$ from Lattice QCD: Determining the Finite-volume\n  Spectra: This work presents technical details of determining the finite-volume energy\nspectra for the scattering amplitude of the coupled-channel $\\pi\\Sigma -\n\\bar{K}N$ from lattice QCD data. The importance of reliably extracting such\nspectra lies in the crucial dependence of the hadronic scattering amplitudes\nanalysis on the energy spectrum when using L\\\"{u}scher's formalism. Results of\nthe methods used are presented and the final finite-volume spectra are shown.\nThe analysis of the scattering amplitude based on these results, exhibits a\ntwo-pole structure for the $\\Lambda(1405)$, a virtual bound state below the\n$\\pi\\Sigma$ threshold and a resonance pole right below the $\\bar{K}N$\nthreshold."
    },
    {
        "anchor": "Latest lattice results of N=1 supersymmetric Yang-Mills theory with some\n  topological insights: We summarise the latest results of our collaboration concerning N=1\nsupersymmetric Yang-Mills theory in four dimensions on the lattice. We\ninvestigate the expected formation of supersymmetric multiplets of the lightest\nparticles and the behaviour of the topological susceptibility approaching the\nsupersymmetric limit of the theory.",
        "positive": "Lattice QCD thermodynamic results with improved staggered fermions: We present results on the QCD equation of state, obtained with two different\nimproved dynamical staggered fermion actions and almost physical quark masses.\nLattice cut-off effect are discussed in detail as results for three different\nlattice spacings are available now, i.e. results have been obtained on lattices\nwith temporal extent of $N_\\tau=4,6$ and 8. Furthermore we discuss the Taylor\nexpansion approach to non-zero baryon chemical potential and present the\nisentropic equation of state on lines of constant entropy per baryon number."
    },
    {
        "anchor": "On the gauge boson's properties in a candidate technicolor theory: The technicolor scenario replaces the Higgs sector of the standard model with\na strongly interacting sector. One candidate for a realization of such a sector\nis two-technicolor Yang-Mills theory coupled to two degenerate flavors of\nadjoint, massless techniquarks. Using lattice gauge theory the properties of\nthe technigluons in this scenario are investigated as a function of the\ntechniquark mass towards the massless limit. For that purpose the minimal\nLandau gauge two-point and three-point correlation functions are determined,\nincluding a detailed systematic error analysis. The results are, within the\nrelatively large systematic uncertainties, compatible with a behavior very\nsimilar to QCD at finite techniquark mass. However, the limit of massless\ntechniquarks exhibits features which could be compatible with a\n(quasi-)conformal behavior.",
        "positive": "A lattice study of the spin structure of the Lambda hyperon: The internal spin structure of the Lambda is of special importance for the\nunderstanding of the spin structure of hadrons in general. The comparison\nbetween the nucleon and Lambda allows for a test of the relevant\nflavour-symmetry breaking effects. Using nonperturbatively O(a) improved Wilson\nfermions in the quenched approximation we have calculated the first moments of\nthe unpolarised, longitudinally polarised and transversity quark distribution\nfunctions in the Lambda. The results indicate that flavour symmetry breaking\nhas little effect on the internal spin structure, in accordance with model\nbased expectations."
    },
    {
        "anchor": "Twenty-first Century Lattice Gauge Theory: Results from the QCD\n  Lagrangian: Quantum chromodynamics (QCD) reduces the strong interactions, in all their\nvariety, to a simple nonabelian gauge theory. It clearly and elegantly explains\nhadrons at short distances, which has led to its universal acceptance. Since\nits advent, however, many of its long-distance, emergent properties have been\nbelieved to be true, without having been demonstrated to be true. This paper\nreviews a variety of results in this regime that have been established with\nlattice gauge theory, directly from the QCD Lagrangian. This body of work sheds\nlight on the origin of hadron masses, its interplay with dynamical symmetry\nbreaking, as well as on other intriguing features such as the phase structure\nof QCD. In addition, nonperturbative QCD is quantitatively important to many\naspects of particle physics (especially the quark flavor sector), nuclear\nphysics, and astrophysics. This review also surveys some of the most\ninteresting connections to those subjects.",
        "positive": "Naive Lattice Fermion without Doublers: We discuss the naive lattice fermion without the issue of doublers. A local\nlattice massless fermion action with chiral symmetry and hermiticity cannot\navoid the doubling problem from the Nielsen-Ninomiya theorem. Here we adopt the\nforward finite-difference deforming the $\\gamma_5$-hermiticity but preserving\nthe continuum chiral-symmetry. The lattice momentum is not hermitian without\nthe continuum limit now. We demonstrate that there is no doubling issue from an\nexact solution. The propagator only has one pole in the first-order accuracy.\nTherefore, it is hard to know the avoiding due to the non-hermiticity. For the\nsecond-order, the lattice propagator has two poles as before. This case also\ndoes not suffer from the doubling problem. Hence separating the forward\nderivative from the backward one evades the doublers under the field theory\nlimit. Simultaneously, it is equivalent to breaking the hermiticity. In the\nend, we discuss the topological charge and also demonstrate the numerical\nimplementation of the Hybrid Monte Carlo."
    },
    {
        "anchor": "Charmonium Potentials at Finite Temperature: The charmonium states at non-zero temperature are studied on anisotropic\nlattices with 2 dynamical quark flavours. Non-local operators are used to\ndetermine the Nambu-Bethe-Salpeter (NBS) wavefunctions via both conventional\nfitting methods and the Maximum Entropy Method. The interquark potential is\ndetermined from the solution of the Schrodinger equation, given the NBS\nwavefunction as input following the HAL QCD method. We observe a temperature\ndependent potential which becomes steeper as the temperature decreases.",
        "positive": "Connection between Tomboulis vortices and projection vortices: By using the freedom of picking a representative we explore connections\nbetween the Tomboulis SO(3)xZ(2) form of the partition function and the SU(2)\nform. We are able to express the monopole and vortex observables of the former\nin terms of configurations of the latter. Also we can measure Tomboulis and\nprojection vortex counters on the same configuration to search for\ncorrelations."
    },
    {
        "anchor": "The HotQCD Equation of State: We present results from recent calculations of the QCD equation of state by\nthe HotQCD Collaboration and review the implications for hydrodynamic modeling.\nThe equation of state of QCD at zero baryon density was calculated on a lattice\nof dimensions $32^3 \\times 8$ with $m_l = 0.1 m_s$ (corresponding to a pion\nmass of $\\sim$220 MeV) using two improved staggered fermion actions, p4 and\nasqtad. C alculations were performed along lines of constant physics using more\nthan 100M cpu-hours on BG/L supercomputers at LLNL, NYBlue, and SDSC. We\npresent paramete rizations of the equation of state suitable for input into\nhydrodynamics models of heavy ion collisions.",
        "positive": "Conformality in twelve-flavour QCD: The spectrum of twelve-flavor QCD has been studied in details by the LatKMI\ncollaboration. In this proceeding we present our updated results for the\nspectrum obtained with the HISQ action at two lattice spacings, several volumes\nand fermion masses. In particular, we emphasize the existence of a\nflavor-singlet scalar state parametrically light with respect to the rest of\nthe spectrum, first reported in our paper. This feature is expected to be\npresent for theories in the conformal window, but the lattice calculation of\nsuch a state is difficult and requires noise-reduction techniques together with\nlarge statistics, in order to evaluate disconnected diagrams. Being able to\nprovide a robust observed connection between a light flavor-singlet scalar and\n(near-)conformality is an important step towards observing a light composite\nHiggs boson in walking technicolor theories on the lattice. We also show\nupdated results for the mass anomalous dimension $\\gamma_m$ obtained from\nvarious spectral quantities, including the string tension, under the assumption\nthat the theory is inside the conformal window."
    },
    {
        "anchor": "Form factors for B and B_s semileptonic decays with NRQCD/HISQ quarks: We discuss preliminaries of a calculation of the form factors for the\nsemileptonic decays B -> pi lv, B_s -> K lv, and B -> K ll. We simulate with\nNRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad\nconfigurations. The form factors are calculated over a range of momentum\ntransfer to allow determination of their shape and the extraction of |V_ub|.\nAdditionally, we are calculating ratios of these form factors to those for the\nunphysical decay B_s -> eta_s. We are studying the possibility of combining\nthese precisely determined ratios with future calculations of B_s ->eta_s using\nHISQ b-quarks to generate form factors with significantly reduced errors.",
        "positive": "Charm physics with Moebius Domain Wall Fermions: We present results showing that Domain Wall fermions are a suitable\ndiscretisation for the simulation of heavy quarks. This is done by a continuum\nscaling study of charm quarks in a M\\\"obius Domain Wall formalism using a\nquenched set-up. We find that discretisation effects remain well controlled by\nthe choice of Domain Wall parameters preparing the ground work for the ongoing\ndynamical $2+1f$ charm program of RBC/UKQCD."
    },
    {
        "anchor": "Transverse-Momentum-Dependent Wave Functions of Pion from Lattice QCD: We present a first lattice QCD calculation of the\ntransverse-momentum-dependent wave functions (TMDWFs) of the pion using\nlarge-momentum effective theory. Numerical simulations are based on one\nensemble with 2+1+1 flavors of highly improved staggered quarks action with\nlattice spacing $a=0.121$~fm from the MILC Collaboration, and one with 2 +1\nflavor clover fermions and tree-level Symanzik gauge action generated by the\nCLS Collaboration with $a=0.098$~fm. As a key ingredient, the soft function is\nfirst obtained by incorporating the one-loop perturbative contributions and a\nproper normalization. Based on this and the equal-time quasi-TMDWFs simulated\non the lattice, we extract the light-cone TMDWFs. The results are comparable\nbetween the two lattice ensembles and a comparison with phenomenological\nparametrization is made. Our studies provide a first attempt of $ab$ $initio$\ncalculation of TMDWFs which will eventually lead to crucial theory inputs for\nmaking predictions for exclusive processes under QCD factorization.",
        "positive": "Lattice Formulation of the N=4 D=3 Twisted Super Yang-Mills: A lattice formulation of a three dimensional super Yang-Mills model with a\ntwisted N=4 supersymmetry is proposed. The extended supersymmetry algebra of\nall eight supercharges is fully and exactly realized on the lattice with a\nmodified \"Leibniz rule\". The formulation we employ here is a three dimensional\nextension of the manifestly gauge covariant method which was developed in our\nprevious proposal of Dirac-K\\\"ahler twisted N=2 super Yang-Mills on a two\ndimensional lattice. The twisted N=4 supersymmetry algebra is geometrically\nrealized on a three dimensional lattice with link supercharges and the use of\n\"shifted\" (anti-)commutators. A possible solution to the recent critiques on\nthe link formulation will be discussed."
    },
    {
        "anchor": "Thermodynamics in quenched QCD: energy--momentum tensor with two-loop\n  order coefficients in the gradient flow formalism: Recently, Harlander et al.\\ [Eur.\\ Phys.\\ J.\\ C {\\bf 78}, 944 (2018)] have\ncomputed the two-loop order (i.e., NNLO) coefficients in the gradient-flow\nrepresentation of the energy--momentum tensor (EMT) in vector-like gauge\ntheories. In this paper, we study the effect of the two-loop order corrections\n(and the three-loop order correction for the trace part of the EMT, which is\navailable through the trace anomaly) on the lattice computation of\nthermodynamic quantities in quenched QCD. The use of the two-loop order\ncoefficients generally reduces the $t$~dependence of the expectation values of\nthe EMT in the gradient-flow representation, where $t$~is the flow time. With\nthe use of the two-loop order coefficients, therefore, the $t\\to0$\nextrapolation becomes less sensitive to the fit function, the fit range, and\nthe choice of the renormalization scale; the systematic error associated with\nthese factors is considerably reduced.",
        "positive": "On The Deconfinement Transition in SU(4) Lattice Gauge Theory: The deconfinement transition in SU(4) lattice gauge theory is investigated on\nN_s^3 X N_t lattices for N_s = 8-16 and N_t = 4-8 using a modified Wilson\naction which is expected to be free of any bulk transitions. The susceptibility\nchi_{|L|}^{max}, where L is the order parameter for deconfinement, is found to\nincrease linearly with spatial volume for N_t = 4, 5, and 6, indicating a first\norder deconfinement phase transition. The latent heat of the transition is\nestimated to be approximately 2/3 of the corresponding ideal gas energy density\nat T_c."
    },
    {
        "anchor": "Probing for the Trace Estimation of a Permuted Matrix Inverse\n  Corresponding to a Lattice Displacement: In this work, we study probing for the more general problem of computing the\ntrace of a permutation of $A^{-1}$, say $PA^{-1}$. The motivation comes from\nLattice QCD where we need to construct \"disconnected diagrams\" to extract\nflavor-separated Generalized Parton functions. In Lattice QCD, where the matrix\nhas a 4D toroidal lattice structure, these non-local operators correspond to a\n$PA^{-1}$ where $P$ is the permutation relating to some displacement $\\vec{p}$\nin one or more dimensions. We focus on a single dimension displacement ($p$)\nbut our methods are general. We show that probing on $A^k$ or $(PA)^k$ do not\nannihilate the largest magnitude elements. To resolve this issue, our\ndisplacement-based probing works on $PA^k$ using a new coloring scheme that\nworks directly on appropriately displaced neighborhoods on the lattice. We\nprove lower bounds on the number of colors needed, and study the effect of this\nscheme on variance reduction, both theoretically and experimentally on a\nreal-world Lattice QCD calculation. We achieve orders of magnitude speedup over\nthe unprobed or the naively probed methods.",
        "positive": "A Concise Force Calculation for Hybrid Monte Carlo with Improved Actions: We present a concise way to calculate force for Hybrid Monte Carlo with\nimproved actions using the fact that changes in thin and smeared link matrices\nlie in their respective tangent vector spaces. Since hypercubic smearing\nschemes are very memory intensive, we also present a memory optimized\nimplementation of them."
    },
    {
        "anchor": "Nucleon form factors from high statistics mixed-action calculations with\n  2+1 flavors: We present new high-statistics results for nucleon form factors at pion\nmasses of approximately 290, 350, 500, and 600 MeV using a mixed action of\ndomain wall valence quarks on an improved staggered sea. We perform chiral fits\nto both vector and axial form factors and compare our results to experiment.",
        "positive": "Charmonium correlators at finite temperature in quenched lattice QCD: We study charmonium correlators at finite temperature using quenched lattice\nQCD simulations. Two analysis procedures are applied to extract information on\nthe spectral function: the maximum entropy method, and the $\\chi^2$ fit\nanalyses including the constrained curve fitting. We focus on the low energy\nstructure of the spectral function by applying the smearing technique. We first\ndiscuss the applicability of these methods to the finite temperatures by\nanalyzing the data at T=0 with restricted numbers of degrees of freedom. Then\nwe apply these methods to the correlators at $T>0$. We find no indication of\nmass shift and finite width for the charmonium states at $T\\simeq 0.9T_c$. The\nresults at $T\\simeq 1.1 T_c$ imply that bound-state-like structures may survive\neven above $T_c$."
    },
    {
        "anchor": "Glueballs on the three-sphere: We study the non-perturbative effects of the global features of the\nconfiguration space for SU(2) gauge theory on the three-sphere. The strategy is\nto reduce the full problem to an effective theory for the dynamics of the\nlow-energy modes. By explicitly integrating out the high-energy modes, the\none-loop correction to the effective hamiltonian is obtained. Imposing the\n$\\theta$ dependence through boundary conditions in configuration space\nincorporates the non-perturbative effects of the non-contractable loops in the\nfull configuration space. After this we obtain the glueball spectrum of the\neffective theory with a variational method.",
        "positive": "Finite-size effects on a lattice calculation: We study in this paper the finite-size effects of a non-periodic lattice on a\nlattice calculation. To this end we use a finite lattice equipped with a\ncentral difference derivative with homogeneous boundary conditions to calculate\nthe bosonic mass associated to the Schwinger model. We found that the\nhomogeneous boundary conditions produce absence of fermion doubling and chiral\ninvariance, but we also found that in the continuum limit this lattice model\ndoes not yield the correct value of the boson mass as other models do. We\ndiscuss the reasons for this and, as a result, the matrix which cause the\nfermion doubling problem is identified."
    },
    {
        "anchor": "Electromagnetic finite-size effects to the hadronic vacuum polarization: In order to reduce the current hadronic uncertainties in the theory\nprediction for the anomalous magnetic moment of the muon, lattice calculations\nneed to reach sub-percent accuracy on the hadronic-vacuum-polarization\ncontribution. This requires the inclusion of $\\mathcal{O}(\\alpha)$\nelectromagnetic corrections. The inclusion of electromagnetic interactions in\nlattice simulations is known to generate potentially large finite-size effects\nsuppressed only by powers of the inverse spatial extent. In this paper we\nderive an analytic expression for the $\\mathrm{QED}_{\\mathrm{L}}$ finite-volume\ncorrections to the two-pion contribution to the hadronic vacuum polarization at\nnext-to-leading order in the electromagnetic coupling in scalar QED. The\nleading term is found to be of order $1/L^{3}$ where $L$ is the spatial extent.\nA $1/L^{2}$ term is absent since the current is neutral and a photon far away\nthus sees no charge and we show that this result is universal. Our analytical\nresults agree with results from the numerical evaluation of loop integrals as\nwell as simulations of lattice scalar $U(1)$ gauge theory with stochastically\ngenerated photon fields. In the latter case the agreement is up to\nexponentially suppressed finite-volume effects. For completeness we also\ncalculate the hadronic vacuum polarization in infinite volume using a basis of\n2-loop master integrals.",
        "positive": "GW fermion propagators and chiral condensate: By exploiting the chiral symmetry, we derive analytic formulas for the\nmassless and the massive Ginsparg-Wilson fermion propagators. Using these\nformulas, we derive an expression for the chiral condensate which is the order\nparameter for spontaneous chiral symmetry breaking in QCD. These formulas\nprovide the proper way to compute the fermion propagators and may save a\nsignificant amount of computing time especially for large lattices in four\ndimensions."
    },
    {
        "anchor": "Medium Effects in Parton Distributions: Understanding the effects of a background hadronic medium on hadronic\nobservables is important in the context of hadron structure. Many experiments\nprobing nucleon structure make use of nuclear targets and unraveling the\nmodifications that ensue is a complex task. Using lattice QCD, we investigate\nthe ab initio computation of hadron structure in a medium, focusing on the\nstructure of the pion in a Bose-condensed gas of pions.",
        "positive": "Practical Implementation of Lattice QCD Simulation on Intel Xeon Phi\n  Knights Landing: We investigate implementation of lattice Quantum Chromodynamics (QCD) code on\nthe Intel Xeon Phi Knights Landing (KNL). The most time consuming part of the\nnumerical simulations of lattice QCD is a solver of linear equation for a large\nsparse matrix that represents the strong interaction among quarks. To establish\nwidely applicable prescriptions, we examine rather general methods for the SIMD\narchitecture of KNL, such as using intrinsics and manual prefetching, to the\nmatrix multiplication and iterative solver algorithms. Based on the performance\nmeasured on the Oakforest-PACS system, we discuss the performance tuning on KNL\nas well as the code design for facilitating such tuning on SIMD architecture\nand massively parallel machines."
    },
    {
        "anchor": "The PZ method for estimating determinant ratios, with applications: We introduce a new method for estimating determinants or determinant ratios\nof large matrices, which combines the techniques of Pad\\`{e} approximation with\nrational functions and $Z_{2}$ noise estimation of traces of large matrices.\nThe method requires simultaneously solving several matrix equations, which can\nbe conveniently accomplished using the MR method. We include some preliinary\nresults, and indicate potential applications to non-Hermitian matrices, and\nHybrid Monte Carlo without pseudofermions.",
        "positive": "Continuous $\u03b2$ function for the SU(3) gauge systems with two and\n  twelve fundamental flavors: The gradient flow transformation can be interpreted as continuous real-space\nrenormalization group transformation if a coarse-graining step is incorporated\nas part of calculating expectation values. The method allows to predict\ncritical properties of strongly coupled systems including the renormalization\ngroup $\\beta$ function and anomalous dimensions at nonperturbative fixed\npoints. In this contribution we discuss a new analysis of the continuous\nrenormalization group $\\beta$ function for $N_f=2$ and $N_f=12$ fundamental\nflavors in SU(3) gauge theories based on this method. We follow the approach\ndeveloped and tested for the $N_f=2$ system in arXiv:1910.06408. Here we\npresent further information on the analysis, emphasizing the robustness and\nintuitive features of the continuous $\\beta$ function calculation. We also\ndiscuss the applicability of the continuous $\\beta$ function calculation in\nconformal systems, extending the possible phase diagram to include a 4-fermion\ninteraction. The numerical analysis for $N_f=12$ uses the same set of ensembles\nthat was generated and analyzed for the step scaling function in\narXiv:1909.05842. The new analysis uses volumes with $L \\ge 20$ and determines\nthe $\\beta$ function in the $c=0$ gradient flow renormalization scheme. The\ncontinuous $\\beta$ function predicts the existence of a conformal fixed point\nand is consistent between different operators. Although determinations of the\nstep scaling and continuous $\\beta$ function use different renormalization\nschemes, they both predict the existence of a conformal fixed point around\n$g^2\\sim 6$."
    },
    {
        "anchor": "QCD hadron spectrum with domain wall fermions: We present the QCD hadron spectrum for the cases of both quenched and\ntwo-flavor dynamical domain wall fermions. We compare the results obtained\nusing the Wilson gauge action and a renormalization group improved gauge\naction. Finite volume effects and the dependence on the finite extent of the\nfifth dimension are discussed.",
        "positive": "Numerical study of chiral magnetic effect in quenched SU(2) lattice\n  gauge theory: A possible experimental observation of the chiral magnetic effect in heavy\nion collisions at RHIC was recently reported by the STAR Collaboration. We\nstudy signatures of this effect in SU(2) lattice gluodynamics with the chirally\ninvariant Dirac operator. We find that at zero temperature the local\nfluctuations of an electric current of quarks and chirality fluctuations\nincrease with external Abelian magnetic field. The external magnetic field\nleads to spatial separation of the quark's electric charges. The separation\nincreases with the strength of the magnetic field. As temperature gets higher\nthe dependence of these quantities on the strength of the magnetic field\nbecomes weaker. In the deconfinement phase the local fluctuations of the chiral\ndensity and of the spatial components of the quarks electric current are large\nand are almost independent on the external magnetic field. The local\nfluctuations of the electric charge density decrease with the strength of the\nmagnetic field in this phase."
    },
    {
        "anchor": "The temperature dependence of the chiral condensate in the Schwinger\n  model with Matrix Product States: We present our recent results for the tensor network (TN) approach to lattice\ngauge theories. TN methods provide an efficient approximation for quantum\nmany-body states. We employ TN for one dimensional systems, Matrix Product\nStates, to investigate the 1-flavour Schwinger model. In this study, we compute\nthe chiral condensate at finite temperature. From the continuum extrapolation,\nwe obtain the chiral condensate in the high temperature region consistent with\nthe analytical calculation by Sachs and Wipf.",
        "positive": "Momentum dependence of the N to Delta transition form factors: We present a new method to determine the momentum dependence of the N to\nDelta transition form factors and demonstrate its effectiveness in the quenched\ntheory at $\\beta=6.0$ on a $32^3 \\times 64$ lattice. We address a number of\ntechnical issues such as the optimal combination of matrix elements and the\nsimultaneous overconstrained analysis of all lattice vector momenta\ncontributing to a given momentum transfer squared, $Q^2$."
    },
    {
        "anchor": "The muon anomalous magnetic moment, a view from the lattice: We review some of the issues that arise in attempts to compute the hadronic\ncorrections to the muon anomalous magnetic moment using Lattice QCD. We\nconcentrate on the dominant contribution, which requires an accurate evaluation\nof the hadronic vacuum polarization.",
        "positive": "Gauge invariance in a Z_2 hamiltonian lattice gauge theory: We propose an efficient variational method for $Z_2$ lattice gauge theory\nbased on the matrix product ansatz. The method is applied to ladder and square\nlattices. The Gauss law needs to be imposed on quantum states to guarantee\ngauge invariance when one studies gauge theory in hamiltonian formalism. On the\nladder lattice, we identify gauge invariant low-lying states by evaluating\nexpectation values of the Gauss law operator after numerical diagonalization of\nthe gauge hamiltonian. On the square lattice, the second order phase transition\nis well reproduced."
    },
    {
        "anchor": "Lattice Approach to the $\u0394I=1/2$ Rule: We discuss a number of old and new methods for computing $K\\to\\pi\\pi$\namplitudes on the lattice. They all involve a non-perturbative determination of\nmatching coefficients. We show how problems related to operator mixing can be\ngreatly reduced by using point-split hadronic currents.",
        "positive": "D-meson decay constants and a check of factorization in non-leptonic\n  B-decays: We compute the vector meson decay constants fD*, fDs* from the simulation of\ntwisted mass QCD on the lattice with Nf = 2 dynamical quarks. When combining\ntheir values with the pseudoscalar D(s)-meson decay constants, we were able (i)\nto show that the heavy quark spin symmetry breaking effects with the charm\nquark are large, fDs*/fDs = 1.26(3), and (ii) to check the factorization\napproximation in a few specific B-meson non-leptonic decay modes. Besides our\nmain results, fD* = 278 \\pm 13 \\pm 10 MeV, and fDs* = 311 \\pm 9 MeV, other\nphenomenologically interesting results of this paper are: fDs*/fD* = 1.16 \\pm\n0.02 \\pm 0.06, fDs*/fD = 1.46 \\pm 0.05 \\pm 0.06, and fDs/fD* = 0.89 \\pm 0.02\n\\pm 0.03. Finally, we correct the value for B(B0 \\rightarrow D+ pi-) quoted by\nPDG, and find B(B0 \\rightarrow D+ pi-) = (7.8 \\pm 1.4) \\times 10-7.\nAlternatively, by using the ratios discussed in this paper, we obtain B(B0\n\\rightarrow D+ pi-) = (8.3 \\pm 1.0 \\pm 0.8)\\times10-7."
    },
    {
        "anchor": "Restoration of chiral symmetry in cold and dense Nambu--Jona-Lasinio\n  model with tensor renormalization group: We analyze the chiral phase transition of the Nambu--Jona-Lasinio model in\nthe cold and dense region on the lattice developing the Grassmann version of\nthe anisotropic tensor renormalization group algorithm. The model is formulated\nwith the Kogut--Susskind fermion action. We use the chiral condensate as an\norder parameter to investigate the restoration of the chiral symmetry. The\nfirst-order chiral phase transition is clearly observed in the dense region at\nvanishing temperature with $\\mu/T\\sim O(10^3)$ on a large volume of $V=1024^4$.\nWe also present the results for the equation of state.",
        "positive": "Hamiltonian domain wall fermions at strong coupling: We apply strong-coupling perturbation theory to gauge theories containing\ndomain-wall fermions in Shamir's surface version. We construct the effective\nHamiltonian for the color-singlet degrees of freedom that constitute the\nlow-lying spectrum at strong coupling. We show that the effective theory is\nidentical to that derived from naive, doubled fermions with a mass term, and\nhence that domain-wall fermions at strong coupling suffer both doubling and\nexplicit breaking of chiral symmetry. Since we employ a continuous fifth\ndimension whose extent tends to infinity, our result applies to overlap\nfermions as well."
    },
    {
        "anchor": "Vortex percolation and confinement: The vortex state which arises from a projection of SU(2) to $Z_2$ gauge\ntheory is studied at finite temperatures with a special emphasis on the\ndeconfinement phase transition.",
        "positive": "A $N_f = 2 + 1 + 1$ \"twisted\" determination of the $b$-quark mass,\n  $f_{B}$ and $f_{B_s}$: We present a lattice QCD determination of the $b$-quark mass and of the\n$f_{B_s}$ and $f_B$ decay constants performed with $N_f = 2 + 1 + 1$ twisted\nmass Wilson fermions. We have used simulations at three values of the lattice\nspacing generated by ETMC with pion masses ranging from 210 to 440 MeV. To\nobtain physical quantities we performed a combined chiral and continuum limit\nand an extrapolation in the heavy quark mass from the charm to the $b$-quark\nregion using suitable ratios calculated at nearby heavy-quark masses having an\nexactly known static limit. Our results are: $m_b(m_b) = 4.29 (13)$ GeV, $f_B =\n196 (9)$ MeV, $f_{B_s} = 235 (9)$ MeV, $f_{B_s} / f_B = 1.201 (25)$,\n$(f_{B_s}/f_B)/(f_K/f_\\pi) = 1.007 (16)$ and $(f_{B_s}/f_B)/(f_{D_s}/f_D) =\n1.008 (13)$."
    },
    {
        "anchor": "Chiral Symmetry Breaking and Chiral Polarization: Tests for Finite\n  Temperature and Many Flavors: It was recently conjectured that, in SU(3) gauge theories with fundamental\nquarks, valence spontaneous chiral symmetry breaking is equivalent to\ncondensation of local dynamical chirality and appearance of chiral polarization\nscale $\\Lambda_{ch}$. Here we consider more general association involving the\nlow-energy layer of chirally polarized modes which, in addition to its width\n($\\Lambda_{ch}$), is also characterized by volume density of participating\nmodes ($\\Omega$) and the volume density of total chirality ($\\Omega_{ch}$). Few\npossible forms of the correspondence are discussed, paying particular attention\nto singular cases where $\\Omega$ emerges as the most versatile characteristic.\nThe notion of finite-volume \"order parameter\", capturing the nature of these\nconnections, is proposed. We study the effects of temperature (in N$_f$=0 QCD)\nand light quarks (in N$_f$=12), both in the regime of possible symmetry\nrestoration, and find agreement with these ideas. In N$_f$=0 QCD, results from\nseveral volumes indicate that, at the lattice cutoff studied, the deconfinement\ntemperature $T_c$ is strictly smaller than the overlap-valence chiral\ntransition temperature $T_{ch}$ in real Polyakov line vacuum. Somewhat similar\nintermediate phase (in quark mass) is also seen in N$_f$=12. It is suggested\nthat deconfinement in N$_f$=0 is related to indefinite convexity of absolute\nX-distributions.",
        "positive": "The overlap operator as a continued fraction: We use a continued fraction expansion of the sign-function in order to obtain\na five dimensional formulation of the overlap lattice Dirac operator. Within\nthis formulation the inverse of the overlap operator can be calculated by a\nsingle Krylov space method where nested conjugate gradient procedures are\navoided. We show that the five dimensional linear system can be made well\nconditioned using equivalence transformations on the continued fractions. This\nis of significant importance when dynamical overlap fermions are simulated."
    },
    {
        "anchor": "Spontaneous symmetry breaking in a two-doublet lattice Higgs model: An SU(2) lattice gauge theory with two doublets of complex scalar fields is\nconsidered. All continuous symmetries are identified and, using the\nnonperturbative methods of lattice field theory, the phase diagram is mapped\nout by direct numerical simulation. Two-doublet models contain phase\ntransitions that separate qualitatively distinct regions of the parameter\nspace. In some regions global symmetries are spontaneously broken. For some\nspecial choices of the model parameters, the symmetry-breaking order parameter\nis calculated. The pattern of symmetry breaking is verified further through\nobservation of Goldstone bosons.",
        "positive": "K pi scattering for isospin 1/2 and 3/2 in lattice QCD: We simulate K pi scattering in s-wave and p-wave for both isospins I=1/2, 3/2\nusing quark-antiquark and meson-meson interpolating fields. We extract the\nelastic phase shifts delta at several values of the K-pi relative momenta. The\nresulting phases exhibit qualitative agreement with the experimental phases in\nall four channels. We express the s-wave phase shifts near threshold in terms\nof the scattering length and the effective range. Our K pi system has zero\ntotal momentum and is simulated on a single ensemble with two dynamical quarks,\nso results apply for mpi=266 MeV and mK=552 MeV in our simulation. The\nbacktracking contractions in both I=1/2 channels are handled by the use of\nLaplacian-Heavyside smeared quarks within the distillation method. Elastic\nphases are extracted from the energy levels using Luscher's relations. In all\nfour channels we observe the expected K(n)pi(-n) scattering states, which are\nshifted due to the interaction. In both attractive I=1/2 channels we observe\nadditional states that are related to resonances; we attribute them to\nK_0^*(1430) in s-wave and K*(892), K*(1410) and K*(1680) in p-wave."
    },
    {
        "anchor": "Finite ma corrections for sea quark matrix elements: We discuss the finite $ma$ corrections associated with the computation of sea\nquark matrix elements. We find them to differ from the standard normalization\nused for valence quarks and to depend strongly on the Lorentz structure of the\ncurrent under consideration. Phenomenological implications of these results are\nbriefly discussed in two examples. We also mention how the magnitude of the\ncorrection factors can be reduced by using a 2-link improved action.",
        "positive": "Fermion number anomaly with the fluffy mirror fermion: Quite recently, Grabowska and Kaplan presented a 4-dimensional lattice\nformulation of chiral gauge theories based on the chiral overlap operator. We\nstudy this formulation from the perspective of the fermion number anomaly and\npossible associated phenomenology. A simple argument shows that the consistency\nof the formulation implies that the fermion with the opposite chirality to the\nphysical one, the \"fluffy mirror fermion\" or \"fluff\", suffers from the fermion\nnumber anomaly in the same magnitude (with the opposite sign) as the physical\nfermion. This immediately shows that if at least one of the fluff quarks is\nmassless, the formulation provides a simple viable solution to the strong CP\nproblem. Also, if the fluff interacts with gravity essentially in the same way\nas the physical fermion, the formulation can realize the asymmetric dark matter\nscenario."
    },
    {
        "anchor": "Chiral critical behavior of 3D lattice fermionic models with quartic\n  interactions: We study the critical behavior of the three-dimensional (3D) Gross-Neveu (GN)\nmodel with $N_f$ Dirac fermionic flavors and quartic interactions, at the\nchiral ${\\mathbb Z}_2$ transition in the massless ${\\mathbb Z}_2$-symmetric\nlimit. For this purpose, we consider a lattice GN model with staggered\nKogut-Susskind fermions and a scalar field coupled to the scalar bilinear\nfermionic operator, which effectively realizes the attractive four-fermion\ninteraction. We perform Monte Carlo (MC) simulations for $N_f=4,8,12,16$. By\nmeans of finite-size scaling analyses of the numerical data, we obtain\nestimates of the critical exponents that are compared with the large-$N_f$\npredictions obtained using the continuum GN field theory. We observe a\nsubstantial agreement. This confirms that lattice GN models with staggered\nfermions provide a nonpertubative realization of the GN quantum field theory,\neven though the lattice interactions explicitly break the flavor ${\\rm\nU}(N_f)\\otimes {\\rm U}(N_f)$ symmetry of the GN field theory, which is only\nrecovered in the critical limit.",
        "positive": "Lattice QCD: concepts, techniques and some results: I give a brief introduction to lattice QCD for non-specialists."
    },
    {
        "anchor": "Lattice operators for scattering of particles with spin: We construct operators for simulating the scattering of two hadrons with spin\non the lattice. Three methods are shown to give the consistent operators for\nPN, PV, VN and NN scattering, where P, V and N denote pseudoscalar, vector and\nnucleon. Explicit expressions for operators are given for all irreducible\nrepresentations at lowest two relative momenta. Each hadron has a good helicity\nin the first method. The hadrons are in a certain partial wave L with total\nspin S in the second method. These enable the physics interpretations of the\noperators obtained from the general projection method. The correct\ntransformation properties of the operators in all three methods are proven. The\ntotal momentum of two hadrons is restricted to zero since parity is a good\nquantum number in this case.",
        "positive": "On the low fermionic eigenmode dominance in QCD on the lattice: We demonstrate the utility of a spectral approximation to fermion loop\noperators using low-lying eigenmodes of the hermitian Dirac-Wilson matrix, Q.\nThe investigation is based on a total of 400 full QCD vacuum configurations,\nwith two degenerate flavors of dynamical Wilson fermions at beta =5.6, at two\ndifferent sea quark masses. The spectral approach is highly competitive for\naccessing both topological charge and disconnected diagrams, on large lattices\nand small quark masses. We propose suitable partial summation techniques that\nprovide sufficient saturation for estimating Tr Q^{-1}, which is related to the\ntopological charge. In the effective mass plot of the eta' meson we achieved a\nconsistent early plateau formation, by ground state projecting the connected\npiece of its propagator."
    },
    {
        "anchor": "Gradient-flowed thermal correlators: how much flow is too much?: Gradient flow has been proposed in the lattice community as a tool to reduce\nthe sensitivity of operator correlation functions to noisy UV fluctuations. We\ntest perturbatively under what conditions doing so may contaminate the results.\nTo do so, we compute gradient-flowed electric field two-point correlators and\nstress tensor one- and two-point correlators at finite temperature in QCD.\nGradient flow has almost no influence on the value of correlators until a\n(temperature- and separation-dependent) level of flow is reached, after which\nthe correlator is rapidly compromised. We provide a prescription for how much\nflow is \"safe.\"",
        "positive": "Quark and gluon momentum fractions in the pion from $N_f=2+1+1$ lattice\n  QCD: We perform the first full decomposition of the pion momentum into its gluon\nand quark contributions. We employ an ensemble generated by the Extended\nTwisted Mass Collaboration with $N_f=2 + 1 +1$ Wilson twisted mass clover\nfermions at maximal twist tuned to reproduce the physical pion mass. We present\nour results in the $\\overline{\\mathrm{MS}}$ scheme at $2\\gev$. We find\n$\\avgx_{u+d}=0.601(28)$, $\\avgx_s=0.059(13)$, $\\avgx_c=0.019(05)$, and\n$\\avgx_g=0.52(11)$ for the separate contributions, respectively, whose sum\nsaturates the momentum sum rule."
    },
    {
        "anchor": "Current progress on the semileptonic form factors for $\\bar{B} \\to\n  D^{\\ast} \\ell \\bar\u03bd$ decay using the Oktay-Kronfeld action: We present recent progress in calculating the semileptonic form factors\n$h_{A_1}(w)$ for the $\\bar{B} \\to D^{\\ast} \\ell \\bar{\\nu}$ decays. We use the\nOktay-Kronfeld (OK) action for the charm and bottom valence quarks and the HISQ\naction for light quarks. We adopt the Newton method combined with the scanning\nmethod to find a good initial guess for the $\\chi^2$ minimizer in the fitting\nof the 2pt correlation functions. The main advantage is that the Newton method\nlets us to consume all the time slices allowed by the physical positivity. We\nreport the first, reliable, but preliminary results for $h_{A_1}(w)/\\rho_{A_1}$\nat zero recoil ($w=1$). Here we use a MILC HISQ ensemble ($a = 0.12$ fm,\n$M_{\\pi}$ = 220 MeV, and $N_f = 2 + 1 + 1$ flavors).",
        "positive": "Fixed versus random triangulations in 2D simplicial Regge calculus: We study 2D quantum gravity on spherical topologies using the Regge calculus\napproach with the $dl/l$ measure. Instead of a fixed non-regular triangulation\nwhich has been used before, we study for each system size four different random\ntriangulations, which are obtained according to the standard Voronoi-Delaunay\nprocedure. We compare both approaches quantitatively and show that the\ndifference in the expectation value of $R^2$ between the fixed and the random\ntriangulation depends on the lattice size and the surface area $A$. We also try\nagain to measure the string susceptibility exponents through a finite-size\nscaling Ansatz in the expectation value of an added $R^2$ interaction term in\nan approach where $A$ is held fixed. The string susceptibility exponent\n$\\gamma_{str}'$ is shown to agree with theoretical predictions for the sphere,\nwhereas the estimate for $\\gamma_{str}$ appears to be too negative."
    },
    {
        "anchor": "Domain-wall fermions and chiral symmetries: We investigate chiral properties of the domain-wall fermion (DWF) system.\nAfter a brief introduction for the DWF, we summarize the recent numerical\nresults on the chiral properties of the domain-wall QCD (DWQCD), which seem\nmutually inconsistent. We next derive a formula which connects a chiral\nsymmetry breaking term in the five dimensional DWF Ward-Takahashi identity with\nthe four-dimensional hermitian Wilson-Dirac operator. Based on this formula, we\npropose a solution, which resolves the inconsistency among recent numerical\ndata, and give a consistent picture of the chiral properties of the DWQCD.",
        "positive": "Probing the QCD vacuum with flavour singlet objects: $\u03b7'$ on the\n  lattice: We present a study on the direct determination of the $\\eta '$ mass on the\nfull set of SESAM and T$\\chi$L QCD vacuum configurations with 2 active flavours\nof Wilson fermions, at $\\beta = 5.6$. We observe a definite dependency of the\ntwo-loop correlator on the topological charge sector."
    },
    {
        "anchor": "Two-flavor QCD Thermodynamics using Anisotropic Lattices: Numerical simulations of full QCD on anisotropic lattices provide a\nconvenient way to study QCD thermodynamics with fixed physics scales and\nreduced lattice spacing errors. We report results from calculations with two\nflavors of dynamical staggered fermions, where all bare parameters and the\nrenormalized anisotropy are kept constant and the temperature is changed in\nsmall steps by varying only the number of time slices. Including results from\nzero-temperature scale setting simulations, which determine the Karsch\ncoefficients, allows for the calculation of the equation of state at finite\ntemperatures.",
        "positive": "WChPT analysis of twisted mass lattice data: We perform a Wilson Chiral Perturbation Theory (WChPT) analysis of quenched\ntwisted mass lattice data. The data were generated by two independent groups\nwith three different choices for the critical mass. For one choice, the\nso-called pion mass definition, one observes a strong curvature for small quark\nmasses in various mesonic observables (''bending phenomenon''). Performing a\ncombined fit to the next-to-leading (NLO) expressions, we find that WChPT\ndescribes the data very well and the fits provide very reasonable values for\nthe low-energy parameters."
    },
    {
        "anchor": "Nucleon structure from generalized parton distributions in lattice QCD: This talk presents results from the QCDSF-UKQCD collaboration for moments of\nleading twist generalized parton distributions in two-flavor lattice QCD based\non O(a) improved Wilson Fermions. We study helicity independent and helicity\nflip GPDs with a focus on densities of quarks in the transverse plane.",
        "positive": "The Casimir effect and deconfinement phase transition: We show that the Casimir effect may lead to a deconfinement phase transition\ninduced by the presence of boundaries in confining gauge theories. Using\nfirst-principle numerical simulations we demonstrate this phenomenon in the\nsimplest case of the compact lattice electrodynamics in two spatial dimensions.\nWe find that the critical temperature of the deconfinement transition in the\nvacuum between two parallel dielectric/metallic wires is a monotonically\nincreasing function of the separation between the wires. At infinite separation\nthe wires do not affect the critical temperature while at small separations the\nvacuum between the wires looses the confinement property due to modification of\nvacuum fluctuations of virtual monopoles."
    },
    {
        "anchor": "The lattice Landau gauge gluon propagator at zero and finite temperature: We study the Landau gauge gluon propagator at zero and finite temperature\nusing lattice simulations. Particular attention is given to the finite size\neffects and to the infrared behaviour.",
        "positive": "Improved currents for $\\bar{B}\\to D^{(*)}\\ell\\bar\u03bd$ form factors\n  from Oktay-Kronfeld heavy quarks: The CKM matrix element $|V_{cb}|$ can be extracted by combining\nexperimentally determined branching fractions for $\\bar{B}\\to\nD^{(*)}\\ell\\bar{\\nu}$ decays with form factors from the lattice. While\nsuccessful, the precision of this approach has been limited by heavy-quark\ndiscretization effects. An improved version of the Fermilab action, the\nOktay-Kronfeld action, can be used to reduce heavy-quark discretization effects\nin calculations performed at the physical bottom and charm quark masses.\nTreating charm and bottom quarks as massive, we are carrying out improvement of\nthe flavor-changing currents through third order in the momentum (HQET)\nexpansion."
    },
    {
        "anchor": "Lattice simulations of adjoint QCD with one Dirac overlap fermion: In this work we investigate the infrared behaviour of a Yang-Mills theory\ncoupled to a massless fermion in the adjoint representation of the gauge group\nSU(2). This model has many interesting properties, corresponding to the\n$\\mathcal{N}=2$ Super-Yang-Mills theory without scalars and in the recent years\nthere has been an increasing interest toward understanding whether confinement\nand fermion condensation occur at low energy. We simulate the theory on the\nlattice close to the massless limit using the overlap discretization of the\nfermion action, allowing a precise and clean study of the chiral symmetry\nbreaking pattern and of the fermion condensate. We present results for the\nscale setting, the condensate and the running of the coupling constant through\nthe gradient flow -- all of them pointing to a theory without an infrared fixed\npoint and remaining confined deep in the infrared regime.",
        "positive": "Static quark anti-quark interactions in zero and finite temperature QCD.\n  I. Heavy quark free energies, running coupling and quarkonium binding: We analyze heavy quark free energies in 2-flavor QCD at finite temperature\nand the corresponding heavy quark potential at zero temperature. Static quark\nanti-quark sources in color singlet, octet and color averaged channels are used\nto probe thermal modifications of the medium. The temperature dependence of the\nrunning coupling, $\\alpha_{qq}(r,T)$, is analyzed at short and large distances\nand is compared to zero temperature as well as quenched calculations. In parts\nwe also compare our results to recent findings in 3-flavor QCD. We find that\nthe characteristic length scale below which the running coupling shows almost\nno temperature dependence is almost twice as large as the Debye screening\nradius. Our analysis supports recent findings which suggest that $\\chi_c$ and\n$\\psi\\prime$ are suppressed already at the (pseudo-) critical temperature and\nthus give a probe for quark gluon plasma production in heavy ion collision\nexperiments, while $J/\\psi$ may survive the transition and will dissolve at\nhigher temperatures."
    },
    {
        "anchor": "Current status of Dynamical Overlap project: We discuss the adaptation of the Hybrid Monte Carlo algorithm to overlap\nfermions. We derive a method which can be used to account for the delta\nfunction in the fermionic force caused by the differential of the sign\nfunction. We discuss the algoritmic difficulties that have been overcome, and\nmention those that still need to be solved.",
        "positive": "Rotated twisted-mass: a convenient regularization scheme for isospin\n  breaking QCD and QED lattice calculations: We propose a scheme of lattice twisted-mass fermion regularization which is\nparticularly convenient for application to isospin breaking (IB) QCD and QED\ncalculations, based in particular on the so called RM123 approach, in which the\nIB terms of the action are treated as a perturbation. The main, practical\nadvantage of this scheme is that it allows the calculation of IB effects on\nsome mesonic observables, like e.g. the pi+ - pi0 mass splitting, using lattice\ncorrelation functions in which the quark and antiquark fields in the meson are\nregularized with opposite values of the Wilson parameter r. These correlation\nfunctions are found to be affected by much smaller statistical fluctuations,\nwith respect to the analogous functions in which quark and antiquark fields are\nregularized with the same value of r. Two numerical application of this scheme,\nthat we call \"rotated twisted-mass\", within pure QCD and QCD+QED respectively,\nare also provided for illustration."
    },
    {
        "anchor": "Thermal interquark potentials for bottomonium using NRQCD from the HAL\n  QCD method: We report our preliminary progress in the calculation of the interquark\npotential of bottomonium at non-zero temperature using the HAL QCD method. We\nuse NRQCD correlation functions of non-local mesonic S-wave states to obtain\nthe central potential as a function of temperature. These results have been\nobtained using our anisotropic 2+1 flavour \"Generation 2\" FASTSUM ensembles.",
        "positive": "Improved bilinears in lattice QCD with non-degenerate quarks: We describe the extension of the improvement program for bilinear operators\ncomposed of Wilson fermions to non-degenerate dynamical quarks. We consider\ntwo, three and four flavors, and both flavor non-singlet and singlet operators.\nWe find that there are many more improvement coefficients than with degenerate\nquarks, but that, for three or four flavors, nearly all can be determined by\nenforcing vector and axial Ward identities. The situation is worse for two\nflavors, where many more coefficients remain undetermined."
    },
    {
        "anchor": "Lattice QCD study of static quark and antiquark correlations at finite\n  $T$ via entanglement entropies: With the aim of clarification of color correlations among quarks, we\ninvestigate the color correlation between a static quark and an antiquark\n(static $q\\bar q$) below and above the phase transition temperature $T_c$\nthrough the entanglement entropy(EE). By a quenched lattice QCD calculation on\nan anisotropic lattice adopting the standard Wilson gauge action in the Coulomb\ngauge, we compute a reduced density matrix $\\rho$ defined in the color space,\nand the entanglement entropy $S_{\\rm EE}$ constructed from $\\rho$. The spatial\nvolume is $L^3 = 24^3$ and the temporal extents are $N_T =\n12,13,14,15,16,18,20$ and $24$, with a gauge coupling $\\beta = 5.75$ and a\nrenormalized anisotropy $\\xi = 4.0$, which corresponds to temperatures between\n180 and 370 MeV. From an analysis of $\\rho$ and $S_{\\rm EE}$, the color\ncorrelation between $q\\bar q$ pairs is obtained as a function of the interquark\ndistance $R$ and the temperature $T$. Below $T_c$, the $R$-dependence of the\ncolor correlation resembles that at $T=0$: the quark's color correlation\ngradually decreases as $R$ increases due to the color screening by in-between\ngluons. Above $T_c$, due to the deconfinement phase transition, the color\ncorrelation among quarks is found to quickly dissappear. Further, we\ninvestigate the color screening effect via the screening mass defined by\n$\\rho$, and discuss the differences in the screening properties between the\nsmall and large R regions.",
        "positive": "The Wilson Flow and the finite temperature phase transition: We consider the determination of the finite temperature phase transition in\nthe Yang--Mills SU(3) gauge theory. We compute the difference of the spatial\nand temporal energy density at a physical Wilson flow time. This difference is\nzero in the confined phase and becomes non zero in the deconfined phase. We\nlocate the phase transition by using a new technique based on an exponential\nsmoothing spline. This method is an alternative to the determination of the\nphase transition based on the Polyakov loop susceptibility and can also be used\nwith dynamical fermions."
    },
    {
        "anchor": "Calculation of Non-Leptonic Kaon Decay Amplitudes from $K\\to\u03c0$ Matrix\n  Elements in Quenched Domain-Wall QCD: We explore application of the domain wall fermion formalism of lattice QCD to\ncalculate the $K\\to\\pi\\pi$ decay amplitudes in terms of the $K\\to\\pi$ and $K\\to\n0$ hadronic matrix elements through relations derived in chiral perturbation\ntheory. Numerical simulations are carried out in quenched QCD using domain-wall\nfermion action for quarks and an RG-improved gauge action for gluons on a\n$16^3\\times 32\\times 16$ and $24^3\\times 32\\times 16$ lattice at $\\beta=2.6$\ncorresponding to the lattice spacing $1/a\\approx 2$GeV. Quark loop contractions\nwhich appear in Penguin diagrams are calculated by the random noise method, and\nthe $\\Delta I=1/2$ matrix elements which require subtractions with the quark\nloop contractions are obtained with a statistical accuracy of about 10%. We\nconfirm the chiral properties required of the $K\\to\\pi$ matrix elements.\nMatching the lattice matrix elements to those in the continuum at $\\mu=1/a$\nusing the perturbative renormalization factor to one loop order, and running to\nthe scale $\\mu=m_c=1.3$ GeV with the renormalization group for $N_f=3$ flavors,\nwe calculate all the matrix elements needed for the decay amplitudes. With\nthese matrix elements, the $\\Delta I=3/2$ decay amplitude shows a good\nagreement with experiment in the chiral limit. The $\\Delta I=1/2$ amplitude, on\nthe other hand, is about 50--60% of the experimental one even after chiral\nextrapolation. In view ofthe insufficient enhancement of the $\\Delta I=1/2$\ncontribution, we employ the experimental values for the real parts of the decay\namplitudes in our calculation of $\\epsilon'/\\epsilon$. We find that the $\\Delta\nI=3/2$ contribution is larger than the $\\Delta I=1/2$ contribution so that\n$\\epsilon'/\\epsilon$ is negative and has a magnitude of order $10^{-4}$.\nPossible reasons for these unsatisfactory results are discussed.",
        "positive": "Dual Methods for Lattice Field Theories at Finite Density: We present a dual representation of the partition function of the charged\nscalar field in which the complex action problem at non-zero chemical potential\nis absent. In this dual representation Monte Carlo simulations are possible and\nwe show some physical results obtained with this approach. Furthermore we\npresent a technique to study 2-point functions at finite density. Results for\nthe lattice correlators at various chemical potentials are shown and discussed."
    },
    {
        "anchor": "Effective Theories of Confinement: We review some approaches to describe confinement in terms of effective\n(model) field theories. After a brief discussion of the dual Abelian Higgs\nmodel, we concentrate on a lattice analysis of the Faddeev-Niemi effective\naction conjectured to describe the low-lying excitations of SU(2) gluodynamics.\nWe generalize the effective action such that it contains all operators built\nfrom a unit color vector field n with O(3) symmetry and maximally four\nderivatives. To avoid the presence of Goldstone bosons, we include explicit\nsymmetry breaking terms parametrized by an external field h of mass-dimension\ntwo. We find a mass gap of the order of 1.5 GeV.",
        "positive": "More methods for calculating the topological charge (density) of SU(N)\n  lattice gauge fields in 3+1 dimensions: We revisit old ideas that smearing or blocking an SU(N) lattice gauge field,\nor averaging over an ensemble of fields created in the neighbourhood of that\nfield, can reduce the high frequency fluctuations sufficiently that the naive\nlattice operator for the topological charge density is able to provide a\nreliable measure of the topological charge of the field. We show that these\nthree methods do indeed provide additional simple methods for calculating the\ntotal topological charge, with smearing particularly economical at current\ncouplings. More interestingly, the ensemble average method can also be used to\nexpose the distribution in space-time of the topological charge and this\nconceptually transparent, albeit computationally expensive, method provides a\nuseful benchmark against which to compare other methods. Using this benchmark\nwe find that a few smearing steps are also reliable in exposing the\ndistribution in space-time of the topological charge, thus providing a very\neconomical and simple method for doing so. We also use the same benchmark to\ndetermine what is the number of `cooling' sweeps one needs to perform in order\nto expose the charge density reliably."
    },
    {
        "anchor": "Thermal quarkonium physics in the pseudoscalar channel: The pseudoscalar correlator is an ideal lattice probe for thermal\nmodifications to quarkonium spectra, given that it is not compromised by a\ncontribution from a large transport peak. We construct a perturbative spectral\nfunction incorporating resummed thermal effects around the threshold and vacuum\nasymptotics above the threshold, and compare the corresponding imaginary-time\ncorrelators with continuum-extrapolated lattice data for quenched SU(3) at\nseveral temperatures. Modest differences are observed, which may originate from\nnon-perturbative mass shifts or renormalization factors, however no resonance\npeaks are needed for describing the quenched lattice data for charmonium at and\nabove T ~ 1.1Tc ~ 350 MeV. For comparison, in the bottomonium case a good\ndescription of the lattice data is obtained with a spectral function containing\na single thermally broadened resonance peak.",
        "positive": "The Light Hadron Spectrum and Decay Constants in Quenched Lattice QCD: We present results for light hadrons composed of both degenerate and\nnon-degenerate quarks in quenched lattice QCD. We calculate masses and decay\nconstants using 60 gauge configurations with an $O(a)$--improved fermion action\nat $\\beta = 6.2$. Using the $\\rho$ mass to set the scale, we find hadron masses\nwithin two to three standard deviations of the experimental values (given in\nparentheses): $m_{K^*}=868\\er{9}{8}$~MeV (892~MeV),\n$m_{\\phi}=970\\err{20}{10}$~MeV (1020~MeV), $m_N=820\\err{90}{60}$~MeV (938~MeV),\n$m_\\Delta=1300\\errr{100}{100}$~MeV (1232~MeV) and\n$m_\\Omega=1650\\err{70}{50}$~MeV (1672~MeV). Direct comparison with experiment\nfor decay constants is obscured by uncertainty in current renormalisations.\nHowever, for ratios of decay constants we obtain $f_K/f_\\pi=1.20\\er{3}{2}$\n(1.22) and $f_\\phi/f_\\rho=1.13\\er{2}{3}$ (1.22)."
    },
    {
        "anchor": "Lattice studies of QCD-like theories with many fermionic degrees of\n  freedom: I give an elementary introduction to the study of gauge theories coupled to\nfermions with many degrees of freedom. Besides their intrinsic interest, these\ntheories are candidates for nonperturbative extensions of the Higgs sector of\nthe Standard Model. While related to QCD, these systems can exhibit very\ndifferent behavior from it: they can possess a running gauge coupling with an\ninfrared attractive fixed point (IRFP). I briefly survey recent lattice work in\nthis area.",
        "positive": "Topological Susceptibility of the 2d O(3) Model under Gradient Flow: The 2d O(3) model is widely used as a toy model for ferromagnetism and for\nQuantum Chromodynamics. With the latter it shares --- among other basic aspects\n--- the property that the continuum functional integral splits into topological\nsectors. Topology can also be defined in its lattice regularised version, but\nsemi-classical arguments suggest that the topological susceptibility $\\chi_{\\rm\nt}$ does not scale towards a finite continuum limit. Previous numerical studies\nconfirmed that the quantity $\\chi_{\\rm t}\\, \\xi^{2}$ diverges at large\ncorrelation length $\\xi$. Here we investigate the question whether or not this\ndivergence persists when the configurations are smoothened by the Gradient Flow\n(GF). The GF destroys part of the topological windings; on fine lattices this\nstrongly reduces $\\chi_{\\rm t}$. However, even when the flow time is so long\nthat the GF impact range --- or smoothing radius --- attains $\\xi/2$, we do\nstill not observe evidence of continuum scaling."
    },
    {
        "anchor": "Dirac spectrum representation of Polyakov loop fluctuations in lattice\n  QCD: Dirac spectrum representations of the Polyakov loop fluctuations are derived\non the temporally odd-number lattice, where the temporal length is odd with the\nperiodic boundary condition. We investigate the Polyakov loop fluctuations\nbased on these analytical relations. It is semianalytically and numerically\nfound that the low-lying Dirac eigenmodes have little contribution to the\nPolyakov loop fluctuations, which are sensitive probe for the quark\ndeconfinement. Our results suggest no direct one-to-one corresponding between\nquark confinement and chiral symmetry breaking in QCD.",
        "positive": "Sampling using $SU(N)$ gauge equivariant flows: We develop a flow-based sampling algorithm for $SU(N)$ lattice gauge theories\nthat is gauge-invariant by construction. Our key contribution is constructing a\nclass of flows on an $SU(N)$ variable (or on a $U(N)$ variable by a simple\nalternative) that respect matrix conjugation symmetry. We apply this technique\nto sample distributions of single $SU(N)$ variables and to construct flow-based\nsamplers for $SU(2)$ and $SU(3)$ lattice gauge theory in two dimensions."
    },
    {
        "anchor": "The onset and deconfinement transitions in two-colour QCD: We study two-colour QCD with two flavours of Wilson fermion at non-zero\nchemical potential mu and zero temperature. We find evidence of two separate\ntransitions: an onset transition at mu ~ m_pi/2 where quark number and energy\ndensities increase from zero; and a deconfinement transition at higher mu. The\nmu-dependence of the number and energy densities and the diquark condensate\nindicate that a Fermi surface is formed and that BCS rather than Bose-Einstein\ncondensation dominates at the quark mass considered here, especially beyond the\ndeconfinement transition.",
        "positive": "CP-violating Dashen phase transition in the two-flavor Schwinger model:\n  a study with matrix product states: We numerically study the Hamiltonian lattice formulation of the two-flavor\nSchwinger model using matrix product states. Keeping the mass of the first\nflavor at a fixed positive value, we tune the mass of the second flavor through\na range of negative values, thus exploring a regime where conventional Monte\nCarlo methods suffer from the sign problem and may run into instabilities due\nto zero modes. Our results indicate a phase transition at the point where the\nabsolute value of the second flavor mass approaches the first flavor mass. The\nphase transition is accompanied by the formation of a fermion condensate, a\nsteep drop of the average electric field, and a peak in the bipartite\nentanglement entropy. Our data hints at a second order transition, which is the\n1+1D analog of the CP-violating Dashen phase transition in QCD."
    },
    {
        "anchor": "Multigrid for Chiral Lattice Fermions: Domain Wall: Critical slowing down for the Krylov Dirac solver presents a major obstacle\nto further advances in lattice field theory as it approaches the continuum\nsolution. We propose a new multi-grid approach for chiral fermions, applicable\nto both the 5-d domain wall or 4-d Overlap operator. The central idea is to\ndirectly coarsen the 4-d Wilson kernel, giving an effective domain wall or\noverlap operator on each level. We provide here an explicit construction for\nthe Shamir domain wall formulation with numerical tests for the 2-d Schwinger\nprototype, demonstrating near ideal multi-grid scaling. The framework is\ndesigned for a natural extension to 4-d lattice QCD chiral fermions, such as\nthe M\\\"obius, Zolotarev or Borici domain wall discretizations or directly to a\nrational expansion of the 4-d Overlap operator. For the Shamir operator, the\neffective overlap operator is isolated by the use of a Pauli-Villars\npreconditioner in the spirit of the K\\\"ahler-Dirac spectral map used in a\nrecent staggered MG algorithm [1].",
        "positive": "Characterization of phases and boundary effects in U(1) gauge theory: We show that the two phases of the 4-dimensional compact U(1) lattice gauge\ntheory are characterized by the existence or absence of an infinite current\nnetwork, defining ``infinite'' on a finite lattice in a manner appropriate to\nthe chosen boundary conditions. In addition for open and fixed boundary\nconditions we demonstrate the effects of inhomogeneities and provide examples\nof the reappearance of an energy gap."
    },
    {
        "anchor": "Lattice QCD Study for Gluon Propagator and Gluon Spectral Function: We study the gluon propagator in the Landau gauge in SU(3) lattice QCD at\n$\\beta$=5.7, 5.8 and 6.0 at the quenched level. The Euclidean Landau-gauge\ngluon propagator $D(r)\\equiv D_{\\mu\\mu}^{aa}(x)/24$ is found to be well\ndescribed by four-dimensional Yukawa-type function $e^{-mr}/r$ in the infrared\nand intermediate region of $r \\equiv (x_\\mu x_\\mu)^{1/2}$ = 0.1 $\\sim$ 1.0fm.\nThe infrared effective gluon mass is obtained as $m \\simeq$ 600MeV. Associated\nwith the 4D Yukawa-type gluon propagator, we derive analytical expressions for\nthe zero-spatial-momentum propagator $D_0(t)$, the effective mass $M_{\\rm\neff}(t)$, and the spectral function $\\rho(\\omega)$ of the gluon field.\nRemarkably, the obtained gluon spectral function $\\rho(\\omega)$ is almost\nnegative definite, except for a positive $\\delta$-functional peak at\n$\\omega=m$. Since the Yukawa-type propagation indicates a three-dimensional\nspace-time character, we consider a hypothesis of an effective dimensional\nreduction by generalized Parisi-Sourlas mechanism in a stochastic\ncolor-magnetic vacuum of infrared QCD.",
        "positive": "$B_s \\rightarrow D_s^*$ Form Factors for the full $q^2$ range from\n  Lattice QCD: We compute the Standard Model semileptonic vector and axial-vector form\nfactors for $B_s\\to D_s^*$ decay across the full $q^2$ range using lattice QCD.\nWe use the Highly Improved Staggered Quark (HISQ) action for all valence\nquarks, enabling us to normalise weak currents nonperturbatively. We use gluon\nfield configurations including $u$, $d$, $s$ and $c$ HISQ sea quarks and\nmultiple HISQ heavy quarks with masses from the $c$ mass up to that of the $b$\non our finest lattices. We determine the physical form factors, with which we\nconstruct the differential and total rates for $\\Gamma(B_s^0\\to\nD_s^{*-}\\ell^+{\\nu}_\\ell)$. We find\n$\\Gamma_{\\ell=e}/|\\eta_\\mathrm{EW}V_{cb}|^2=2.07(17)_\\mathrm{latt}(2)_\\mathrm{EM}\\times\n10^{13} ~\\mathrm{s}^{-1}$,\n$\\Gamma_{\\ell=\\mu}/|\\eta_\\mathrm{EW}V_{cb}|^2=2.06(16)_\\mathrm{latt}(2)_\\mathrm{EM}\\times\n10^{13} ~\\mathrm{s}^{-1}$ and\n$\\Gamma_{\\ell=\\tau}/|\\eta_\\mathrm{EW}V_{cb}|^2=5.14(37)_\\mathrm{latt}(5)_\\mathrm{EM}\\times\n10^{12} ~\\mathrm{s}^{-1}$, where $\\eta_\\mathrm{EW}$ contains the electroweak\ncorrection to $G_F$, the first uncertainty is from our lattice calculation, and\nthe second allows for long-distance QED effects. We compute the ratio\n$R(D_s^{*-})\\equiv\n\\Gamma_{\\ell=\\tau}/\\Gamma_{\\ell=\\mu}=0.2490(60)_\\mathrm{latt}(35)_\\mathrm{EM}$\nand obtain a value for the ratio of decay rates $\\Gamma_{\\ell=\\mu}(B_s\\to\nD_s)/\\Gamma_{\\ell=\\mu}(B_s\\to D_s^*)=0.443(40)_\\mathrm{latt}(4)_\\mathrm{EM}$,\nwhich agrees well with recent LHCb results. We determine $|V_{cb}|=42.2\n(1.5)_\\mathrm{latt}(1.7)_\\mathrm{exp}(0.4)_\\mathrm{EM} \\times 10^{-3}$ by\ncombining our lattice results across the full q^2 range with experimental\nresults from LHCb. A comparison of our results to the normalised differential\ndecay rate from LHCb shows good agreement. We also test the impact of new\nphysics couplings on observables sensitive to lepton flavor universality\nviolation."
    },
    {
        "anchor": "Singularities of QCD in the complex chemical potential plane: We study the thermodynamic singularities of QCD in the complex chemical\npotential plane by a numerical simulation of lattice QCD, and discuss a method\nto understand the nature of the QCD phase transition at finite density from the\ninformation of the singularities. The existence of singular points at which the\npartition function (Z) vanishes is expected in the complex plane. These are\ncalled Lee-Yang zeros or Fisher zeros. We investigate the distribution of these\nsingular points using the data obtained by a simulation of two-flavor QCD with\np4-improved staggered quarks. The convergence radius of a Taylor expansion of\nln Z in terms of the chemical potential is also discussed.",
        "positive": "Application of chiral perturbation theory to 2+1 flavor lattice QCD with\n  O(a)-improved Wilson quarks: We apply chiral perturbation theory to the pseudoscalar meson mass and decay\nconstant data obtained in the PACS-CS Project toward 2+1 flavor lattice QCD\nsimulations with the O(a)-improved Wilson quarks. We examine the existence of\nchiral logarithms in the quark mass range from m_{ud}=47 MeV down to 6 MeV on a\n(2.8 fm)^3 box with the lattice spacing a=0.09 fm. Several low energy constants\nare determined. We also discuss the magnitude of finite size effects based on\nchiral perturbation theory."
    },
    {
        "anchor": "Lattice quark propagator with staggered quarks in Landau and Laplacian\n  gauges: We report on the lattice quark propagator using standard and improved\nStaggered quark actions, with the standard, Wilson gauge action. The standard\nKogut-Susskind action has errors of \\oa{2} while the ``Asqtad'' action has\n\\oa{4}, \\oag{2}{2} errors. The quark propagator is interesting for studying the\nphenomenon of dynamical chiral symmetry breaking and as a test-bed for\nimprovement. Gauge dependent quantities from lattice simulations may be\naffected by Gribov copies. We explore this by studying the quark propagator in\nboth Landau and Laplacian gauges. Landau and Laplacian gauges are found to\nproduce very similar results for the quark propagator.",
        "positive": "Color dependence of tensor and scalar glueball masses in Yang-Mills\n  theories: We report the masses of the lightest spin-0 and spin-2 glueballs obtained in\nan extensive lattice study of the continuum and infinite volume limits of\n$Sp(N_c)$ gauge theories for $N_c=2,4,6,8$. We also extrapolate the combined\nresults towards the large-$N_c$ limit. We compute the ratio of scalar and\ntensor masses, and observe evidence that this ratio is independent of $N_{c}$.\nOther lattice studies of Yang-Mills theories at the same space-time dimension\nprovide a compatible ratio. We further compare these results to various\nanalytical ones and discuss them in view of symmetry-based arguments related to\nthe breaking of scale invariance in the underlying dynamics, showing that a\nconstant ratio might emerge in a scenario in which the $0^{++}$ glueball is\ninterpreted as a dilaton state."
    },
    {
        "anchor": "Critical behavior of the hopping expansion from the Functional\n  Renormalization Group: A lattice version of the widely used Functional Renormalization Group (FRG)\nfor the Legendre effective action is solved - in principle exactly - in terms\nof graph rules for the linked cluster expansion. Conversely, the FRG induces\nnonlinear flow equations governing suitable resummations of the graph\nexpansion. The (finite) radius of convergence determining criticality can then\nbe efficiently computed as the unstable manifold of a Gaussian or non-Gaussian\nfixed point of the FRG flow. The correspondence is tested on the critical line\nof the L\\\"{u}scher-Weisz solution of the $\\phi^4_4$ theory and its $\\phi_3^4$\ncounterpart.",
        "positive": "Distribution of Instanton and Monopole Clustering: We study the relation between the instanton distribution and the monopole\nloop length in the SU(2) gauge theory with the abelian gauge fixing. We measure\nthe monopole current from the multi-instanton ensemble on the $16^4$ lattice\nusing the maximally abelian gauge. When the instanton density is dilute, there\nappear only small monopole loops. On the other hand, in the dense case, there\nappears one very long monopole loop, which is responsible for the confinement\nproperty, in each gauge configuration. We find a clear monopole clustering in\nthe histogram of the monopole loop length from 240 gauge configurations."
    },
    {
        "anchor": "Generalized parton distributions and transversity from full lattice QCD: We present here the latest results from the QCDSF collaboration for moments\nof generalized parton distributions and transversity in two-flavour QCD,\nincluding a preliminary analysis of the pion mass dependence.",
        "positive": "Lattice study of QCD at finite chiral density: topology and confinement: In this paper we study the properties of QCD at nonzero chiral density\n$\\rho_5$, which is introduced through chiral chemical potential $\\mu_5$. The\nstudy is performed within lattice simulation of QCD with dynamical rooted\nstaggered fermions. We first check that $\\rho_5$ is generated at nonzero\n$\\mu_5$ and in the chiral limit observe $\\rho_5 \\sim \\Lambda_{QCD}^2 \\mu_5$. We\nalso test the possible connection between confinement and topological\nfluctuations. To this end, we measured the topological susceptibility\n$\\chi_{\\mbox{\\footnotesize top}}$ and string tension $\\sigma$ for various\nvalues of $\\mu_5$. We observed that both string tension and chiral\nsusceptibility grow with $\\mu_5$ and there is a strong correlation between\nthese quantities. We thus conclude that the chiral chemical potential enhances\ntopological fluctuations and that these fluctuations can indeed be closely\nrelated to the strength of confinement."
    },
    {
        "anchor": "The Heavy Quark Masses from Quarkonia: We report on the status of the determination of the heavy quark masses from\nour calculation of the quarkonia spectra. All sources of systematic errors that\nenter the quark mass determination are accounted for. We explicitly keep $ma\n\\neq 0$ in the perturbative calculation relating the bare lattice mass to a\nrenormalized mass. Our results are still preliminary.",
        "positive": "Excited states in lattice QCD with the stochastic LapH method: Progress in computing the spectrum of excited baryons and mesons in lattice\nQCD is described. Results in the zero-momentum bosonic I=1/2, S=1, T1u symmetry\nsector of QCD using a correlation matrix of 58 operators are presented. All\nneeded Wick contractions are efficiently evaluated using a stochastic method of\ntreating the low-lying modes of quark propagation that exploits Laplacian\nHeaviside quark-field smearing. Level identification using probe operators is\ndiscussed."
    },
    {
        "anchor": "Applying the Wang-Landau Algorithm to Lattice Gauge Theory: We implement the Wang-Landau algorithm in the context of SU(N) lattice gauge\ntheories. We study the quenched, reduced version of the lattice theory and\ncalculate its density of states for N=20,30,40,50. We introduce a variant of\nthe original algorithm in which the weight function used in the update does not\nasymptote to a fixed function, but rather continues to have small fluctuations\nwhich enhance tunneling. We formulate a method to evaluate the errors in the\ndensity of states, and use the result to calculate the dependence of the\naverage action density and the specific heat on the `t Hooft coupling lambda.\nThis allows us to locate the coupling lambda_t at which a strongly first order\ntransition occurs in the system. For N=20 and 30 we compare our results to\nthose obtained using Ferrenberg-Swendsen multi-histogram reweighting and find\nagreement with errors of 0.2 % or less. Extrapolating our results to N=oo we\nfind 1/lambda_t = 0.3148(2). We remark on the significance of this result for\nthe validity of quenched large-$N$ reduction of SU(N) lattice gauge theories.",
        "positive": "Vector meson electromagnetic form factors: The charge, magnetic and quadrupole form factors of vector mesons and the\ncharge form factor of pseudo-scalar mesons are calculated in quenched lattice\nQCD. The charge radii and magnetic moments are derived. The quark sector\ncontributions to the form factors are calculated separately and we highlight\nthe environmental sensitivity of the light-quark contribution to charge radii."
    },
    {
        "anchor": "Physical Results from Unphysical Simulations: We calculate various properties of pseudoscalar mesons in partially quenched\nQCD using chiral perturbation theory through next-to-leading order. Our results\ncan be used to extrapolate to QCD from partially quenched simulations, as long\nas the latter use three light dynamical quarks. In other words, one can use\nunphysical simulations to extract physical quantities - in this case the quark\nmasses, meson decay constants, and the Gasser-Leutwyler parameters L_4-L_8. Our\nproposal for determining L_7 makes explicit use of an unphysical (yet\nmeasurable) effect of partially quenched theories, namely the double-pole that\nappears in certain two-point correlation functions. Most of our calculations\nare done for sea quarks having up to three different masses, except for our\nresult for L_7, which is derived for degenerate sea quarks.",
        "positive": "Universality of Mixed Action Extrapolation Formulae: Mixed action theories with chirally symmetric valence fermions exhibit very\ndesirable features both at the level of the lattice calculations as well as in\nthe construction and implementation of the low energy mixed action effective\nfield theory. In this work we show that when such a mixed action effective\nfield theory is projected onto the valence sector, both the Lagrangian and the\nextrapolation formulae become universal in form through next to leading order,\nfor all variants of discretization methods used for the sea fermions. Our\nconclusion relies on the chiral nature of the valence quarks. The result\nimplies that for all sea quark methods which are in the same universality class\nas QCD, the numerical values of the physical coefficients in the various mixed\naction chiral Lagrangians will be the same up to lattice spacing dependent\ncorrections. This allows us to construct a prescription to determine the mixed\naction extrapolation formulae for a large class of hadronic correlation\nfunctions computed in partially quenched chiral perturbation theory at the\none-loop level. For specific examples, we apply this prescription to the\nnucleon twist--2 matrix elements and the nucleon--nucleon system. In addition,\nwe determine the mixed action extrapolation formula for the neutron EDM as this\nprovides a nice example of a theta-dependent observable; these observables are\nexceptions to our prescription."
    },
    {
        "anchor": "A Numerical Study of the Hierarchical Ising Model: High Temperature\n  Versus Epsilon Expansion: We study numerically the magnetic susceptibility of the hierarchical model\nwith Ising spins ($\\sigma =\\pm 1$) above the critical temperature and for two\nvalues of the epsilon parameter. The integrations are performed exactly, using\nrecursive methods which exploit the symmetries of the model. Lattices with up\nto $2^18$ sites have been used. Surprisingly, the numerical data can be fitted\nvery well with a simple power law of the form $(1- \\beta /\\beta _c )^{- \\gamma}\n$for the {\\it whole} temperature range. The numerical values for $\\gamma $\nagree within a few percent with the values calculated with a high-temperature\nexpansion but show significant discrepancies with the epsilon-expansion. We\nwould appreciate comments about these results.",
        "positive": "Singlet vs Nonsinglet Perturbative Renormalization of Fermion Bilinears: In this paper we present the perturbative evaluation of the difference\nbetween the renormalization functions of flavor singlet and nonsinglet bilinear\nquark operators on the lattice. The computation is performed to two loops and\nto lowest order in the lattice spacing, for a class of improved lattice\nactions, including Wilson, tree-level (TL) Symanzik and Iwasaki gluons, twisted\nmass and SLiNC Wilson fermions, as well as staggered fermions with twice\nstout-smeared links. In the staggered formalism, the stout smearing procedure\nis also applied to the definition of bilinear operators."
    },
    {
        "anchor": "Kaon semileptonic decays near the physical point: The CKM matrix element $|V_{us}|$ can be extracted from the experimental\nmeasurement of semileptonic $K\\to\\pi$ decays. The determination depends on\ntheory input for the corresponding vector form factor in QCD. We present a\npreliminary update on our efforts to compute it in $N_f=2+1$ lattice QCD using\ndomain wall fermions for several lattice spacings and with a lightest pion mass\nof about $170\\,\\mathrm{MeV}$. By using partially twisted boundary conditions we\navoid systematic errors associated with an interpolation of the form factor in\nmomentum-transfer, while simulated pion masses near the physical point reduce\nthe systematic error due to the chiral extrapolation.",
        "positive": "A physicist-friendly reformulation of the Atiyah-Patodi-Singer index and\n  its mathematical justification: The Atiyah-Patodi-Singer index theorem describes the bulk-edge correspondence\nof symmetry protected topological insulators. The mathematical setup for this\ntheorem is, however, not directly related to the physical fermion system, as it\nimposes on the fermion fields a non-local and unnatural boundary condition\nknown as the \"APS boundary condition\" by hand. In 2017, we showed that the same\ninteger as the APS index can be obtained from the $\\eta$ invariant of the\ndomain-wall Dirac operator. Recently we gave a mathematical proof that the\nequivalence is not a coincidence but generally true. In this contribution to\nthe proceedings of LATTICE 2019, we try to explain the whole story in a\nphysicist-friendly way."
    },
    {
        "anchor": "The pion and proton mass in finite volume: We calculate the finite volume effects for the pion and nucleon mass. For the\npion mass we present the results of a full two-loop calculation in chiral\nperturbation theory. The outcome shows that the resummed version of the Luscher\nformula we presented in an earlier work does indeed give an excellent\napproximation to the two-loop result. In view of this result we apply the same\nresummed formula to the nucleon mass. In the nucleon sector the extension of\nthe chiral expansion to higher quark masses appears to be more problematic and\nit is therefore more difficult to make reliable predictions for the size of the\nfinite volume effects. We present some preliminary numerical estimates.",
        "positive": "Kaon B-parameter using Overlap Fermions: I present first results from an in-progress calculation of B_K in quenched\napproximation using overlap fermions. My particular implementation of the\noverlap uses a kernel with nearest and next-nearest neighbor interactions and\nHYP-blocked gauge connections. Matching to the continuum NDR regularization is\ndone perturbatively. I present preliminary results at beta=5.9 and 6.1 (lattice\nspacings 0.125 and 0.09 fm) for quark masses, pseudoscalar decay constants, and\nB-parameter -- B_K(NDR(mu=2 GeV) is 0.66(3-4)."
    },
    {
        "anchor": "On the removal of the trace mode in lattice ${\\cal N}=4$ super\n  Yang-Mills theory: Twisted and orbifold formulations of lattice ${\\cal N}=4$ super Yang-Mills\ntheory which possess an exact supersymmetry require a $U(N)=SU(N)\\otimes U(1)$\ngauge group. In the naive continuum limit, the $U(1)$ modes trivially decouple\nand play no role in the theory. However, at non-zero lattice spacing they\ncouple to the $SU(N)$ modes and can drive instabilities in the lattice theory.\nFor example, it is well known that the lattice $U(1)$ theory undergoes a phase\ntransition at strong coupling to a chirally broken phase. An improved action\nthat suppresses the fluctuations in the $U(1)$ sector was proposed in\narXiv:1505.03135 . Here, we explore a more aggressive approach to the problem\nby adding a term to the action which can entirely suppress the $U(1)$ mode. The\npenalty is that the new term breaks the $\\mathcal{Q}$-exact lattice\nsupersymmetry. However, we argue that the term is $1/N^2$ suppressed and the\nexistence of a supersymmetric fixed point in the planar limit ensures that any\nSUSY-violating terms induced in the action possess couplings that also vanish\nin this limit. We present numerical results on supersymmetric Ward identities\nconsistent with this conclusion.",
        "positive": "Quantum chaos in supersymmetric Yang-Mills-like model: equation of\n  state, entanglement, and spectral form-factors: We analyze in detail a sharp transition between the low-energy,\nlow-dimensional eigenstates and the high-energy chaotic bulk of the spectrum\nfor a simple supersymmetric quantum-mechanical model with Hamiltonian\n$\\hat{H}_S = \\left(\\hat{p}_1^2 + \\hat{p}_2^2 + \\hat{x}_1^2 \\, \\hat{x}_2^2\n\\right) \\otimes I + \\hat{x}_1 \\otimes \\sigma_1 + \\hat{x}_2 \\otimes \\sigma_3$,\nwhich mimics the structure of the Banks-Fischler-Susskind-Stanford (BFSS)\nmatrix model, the spatially compactified $\\mathcal{N} = 1$ super-Yang-Mills\ntheory. We conjecture that this transition might be similar to the transition\nbetween the $D0$-brane and $M$-theory regimes in the BFSS model, and find that\nit does not lead to irregularities in the thermodynamic equation of state. We\ndemonstrate that real-time spectral form-factor for our supersymmetric model\nexhibits the ``ramp'' behavior typical for quantum chaos. We also analyze the\nentanglement entropy and the spectrum of the reduced density matrix of the\neigenstates of $\\hat{H}_S$, considering one of the bosonic degrees of freedom\nas a subsystem. The entanglement entropy of low-energy eigenstates appears to\nbe practically energy-independent. Exactly at the onset of random-matrix-type\nlevel spacing fluctuations, this behavior rapidly changes into a steady growth\nof entanglement with energy. We demonstrate that the spectrum of the reduced\ndensity matrix also exhibits universal level-spacing fluctuations towards its\nhigher end, even for the ground state of the supersymmetric model. Thus even\nthe regularly spaced, non-chaotic eigenstates contain some information about\nsemi-classical chaotic dynamics at high energies."
    },
    {
        "anchor": "Matrix elements of unstable states: Using the language of non-relativistic effective Lagrangians, we formulate a\nsystematic framework for the calculation of resonance matrix elements in\nlattice QCD. The generalization of the L\\\"uscher-Lellouch formula for these\nmatrix elements is derived. We further discuss in detail the procedure of the\nanalytic continuation of the resonance matrix elements into the complex energy\nplane and investigate the infinite-volume limit.",
        "positive": "Restless pions from orbifold boundary conditions: an explicit\n  construction for noise reduction in lattice QCD: The exponentially decreasing signal to noise ratio in multibaryon correlators\nis the main obstacle to a first principles, QCD-based calculation of the\nnuclear force. Recently, we have proposed an orbifold boundary condition\n(\"restless pions\") that can dramatically improve this matter. Here we develop\nthe idea further by proposing an explicit algorithm that can be used with\npurely periodic, \"off the shelf\" gauge configurations. We also discuss finite\nvolume corrections with the new boundary conditions and the use of the \"Luscher\nformula'' for the phase shifts."
    },
    {
        "anchor": "Tensor renormalization group approach to four-dimensional complex\n  $\u03c6^4$ theory at finite density: Tensor network is an attractive approach to field theory with negative sign\nproblem. The complex $\\phi^4$ theory at finite density is a test bed for\nnumerical algorithms to verify their effectiveness. The model shows a\ncharacteristic feature called the Silver Blaze phenomenon associated with the\nsign problem in the large volume limit at low temperature. We analyze the\nfour-dimensional model employing the anisotropic tensor renormalization group\nalgorithm. We find a clear signal of the Silver Blaze phenomenon on a large\nvolume of $V=1024^4$, which implies that the tensor network approach is\neffective even for four-dimensional field theory beyond two dimensions.",
        "positive": "Locating analytically critical temperature in some statistical systems: We have found a simple criterion which allows for the straightforward\ndetermination of the order-disorder critical temperatures. The method\nreproduces exactly results known for the two dimensional Ising, Potts and\n$Z(N<5)$ models. It also works for the Ising model on the triangular lattice.\nFor systems which are not selfdual our proposition remains an unproven\nconjecture. It predicts $\\beta_c=0.2656...$ for the two coupled layers of Ising\nspins. Critical temperature of the three dimensional Ising model is related to\nthe free energy of the two layer Ising system."
    },
    {
        "anchor": "Susceptibilities and screening masses in two flavor QCD: We studied QCD with two flavors of dynamical staggered quarks at finite\ntemperature, with a bare sea quark mass of about 17 MeV. We report\ninvestigations of baryon, isospin, charge and strangeness susceptibilities, as\nwell as screening masses obtained from correlators of local and one-link\nseparated meson operators. These were studied as functions of valence quark\nmass at several temperatures. Our results for susceptibilities deviate\nsignificantly from ideal gas values, and even more from the weak coupling\nseries. We also report the first measurement of off-diagonal quark number\nsusceptibilities below the transition temperature, Tc, where they are the main\ncontribution to charge fluctuations. We present evidence for a close connection\nbetween the susceptibilities and the screening masses.",
        "positive": "Non-Gaussianity of the topological charge distribution in\n  $\\mathrm{SU}(3)$ Yang-Mills theory: In Yang-Mills theory, the cumulants of the na\\\"ive lattice discretization of\nthe topological charge evolved with the Yang-Mills gradient flow coincide, in\nthe continuum limit, with those of the universal definition. We sketch in these\nproceedings the main points of the proof. By implementing the gradient-flow\ndefinition in numerical simulations, we report the results of a precise\ncomputation of the second and the fourth cumulant of the $\\mathrm{SU}(3)$\nYang-Mills theory topological charge distribution, in order to measure the\ndeviation from Gaussianity. A range of high-statistics Monte Carlo simulations\nwith different lattice volumes and spacings is used to extrapolate the results\nto the continuum limit with confidence by keeping finite-volume effects\nnegligible with respect to the statistical errors. Our best result for the\ntopological susceptibility is $t_0^2\\chi=6.67(7)\\times 10^{-4}$, while for the\nratio between the fourth and the second cumulant we obtain $R=0.233(45)$."
    },
    {
        "anchor": "Thermodynamics of SU(N) gauge theories in 2+1 dimensions in the $T <\\\n  T_c$ regime: We present Monte Carlo results for the thermodynamics of pure SU(N) gauge\ntheories with $N=2,...,6$ in 2+1 dimensions. We focus on the confined phase\nregion $T<T_c$ and study thermodynamics variables such as the trace of the\nenergy-momentum tensor, pressure, energy and entropy density using the integral\nmethod. We also investigate scaling properties with $N$ of the different\nobservables. We compare our results with a gas of free glueballs and the\nbosonic string predictions for the Hagedorn spectrum.",
        "positive": "Lattice QCD study of four-quark components of the isosinglet scalar\n  mesons: Significance of disconnected diagrams: We study the possible significance of four-quark states in the iso-singlet\nscalar mesons ($J^{PC}=0^{++}$, $I=0$) by performing two-flavor full lattice\nQCD simulations on an $8^3 \\times 16$ lattice using the improved gauge action\nand the clover-improved Wilson quark action. In particular, we evaluate the\npropagators of molecular and tetra-quark operators together with singly\ndisconnected diagrams. In the computation of the singly disconnected diagrams\nwe employ the $Z_2$-noise method with the truncated eigenmode approach. We show\nthat the quark loops given by the disconnected diagrams play an essential role\nin propagators of tetraquark and molecular operators."
    },
    {
        "anchor": "Cost of Generalised HMC Algorithms for Free Field Theory: We study analytically the computational cost of the Generalised Hybrid Monte\nCarlo (GHMC) algorithm for free field theory. We calculate the autocorrelation\nfunctions of operators quadratic in the fields, and optimise the GHMC momentum\nmixing angle, the trajectory length, and the integration stepsize. We show that\nlong trajectories are optimal for GHMC, and that standard HMC is much more\nefficient than algorithms based on the Second Order Langevin (L2MC) or Kramers\nEquation. We show that contrary to naive expectations HMC and L2MC have the\nsame volume dependence, but their dynamical critical exponents are z=1 and\nz=3/2 respectively.",
        "positive": "Light Hadron Masses on Coarse Lattices with Improved Actions: The lattice QCD field is currently undergoing a revolution in the manner in\nwhich improvements of the approach are being implemented. We are examining the\nutility of order-a^2-improved tadpole-improved actions for the light fermion\nsector. The masses of the low-lying hadrons are calculated using the\norder-a^2-improved gluon action and the order-a^2-improved 2-link fermion\naction of Hamber and Wu with further tadpole improvement. Initial results on a\n6^3 x 12 lattice at beta = 6.25 and a 10^3 x 16 lattice at beta = 7.0 are\npresented. The corresponding lattice spacings are approximately 0.40 fm and\n0.24 fm respectively. These lattices provide a constant volume in which the\nscaling of observables is assessed."
    },
    {
        "anchor": "Some Considerations on Chiral Gauge Theories: Some general considerations on the problem of non-perturbative definition of\nChiral Gauge Theories are presented.",
        "positive": "Instanton, Monopole and Confinement: We study the correlation between instantons and QCD-monopoles both in the\nlattice gauge theory and in the multi-instanton system using the maximally\nabelian gauge. First, we find the existence of an almost linear correlation\nbetween the total length of monopole trajectories and the total number of\npseudoparticles (instantons and anti-instantons) in the $16^{3}\\times4$ SU(2)\nlattice. Second, we study the features of QCD-monopole in the SU(2)\nmulti-instanton vacuum on the $16^{4}$ lattice as a random ensemble of\npseudoparticles. A signal of monopole condensation is found as the clustering\nof monopole trajectories, when the topological pseudoparticles is sufficiently\ndense."
    },
    {
        "anchor": "Hadronic decay width from finite-volume energy spectrum in lattice QCD: The standard approach to determine the parameters of a resonance is based on\nthe study of the volume dependence of the energy spectrum. In this work we\nstudy a non-linear sigma model coupled to a scalar field in which a resonance\nemerges. Using an analysis method introduced recently, based on the concept of\nprobability distribution, it is possible to determine the mass and the width of\nthe resonance.",
        "positive": "Rough Interfaces Beyond the Gaussian Approximation: We compare predictions of the Capillary Wave Model beyond its Gaussian\napproximation with Monte Carlo results for the energy gap and the surface\nenergy of the 3D Ising model in the scaling region. Our study reveals that the\nfinite size effects of these quantities are well described by the Capillary\nWave Model, expanded to two--loop order ( one order beyond the Gaussian\napproximation)."
    },
    {
        "anchor": "Determinant Calculations with Random Walk Worldline Loops: We propose to calculate bosonic and fermionic determinants with some general\nfield background, and the corresponding 1-loop effective actions by evaluating\nrandom walk worldline loops generated statistically on the lattice. This is\nillustrated by some numerical calculations for constant gauge field backgrounds\nand then discussed for the general case.",
        "positive": "Vortex Structure in Abelian-Projected Lattice Gauge Theory: We report on a breakdown of both monopole dominance and positivity in\nabelian-projected lattice Yang-Mills theory. The breakdown is associated with\nobservables involving two units of the abelian charge. We find that the\nprojected lattice has at most a global $Z_2$ symmetry in the confined phase,\nrather than the global U(1) symmetry that might be expected in a dual\nsuperconductor or monopole Coulomb gas picture. Implications for monopole and\ncenter vortex theories of confinement are discussed."
    },
    {
        "anchor": "The vector and axial vector current in Wilson ChPT: We construct the vector and axial vector currents in Wilson Chiral\nPerturbation Theory (WChPT), the low-energy effective theory for lattice QCD\nwith Wilson fermions.\n  Our construction is slightly different compared to ChPT in continuum QCD,\nwhere the currents are essentially the (partially) conserved currents\nassociated with the chiral symmetries. In WChPT, due to explicit chiral\nsymmetry breaking at non-zero lattice spacing, there appear O(a) terms in the\nexpressions for the currents which do not stem from the effective action. In\naddition, the finite renormalization of the currents needs to be taken into\naccount in order to properly match the currents of the effective theory.\n  As an illustration we compute f_pi to one loop with the renormalized axial\nvector current for a particular renormalization condition. It turns out that\nfor this particular condition some of the O(a) corrections are taken care of by\nthe renormalization.",
        "positive": "A comparison of updating algorithms for large N reduced models: We investigate Monte Carlo updating algorithms for simulating $SU(N)$\nYang-Mills fields on a single-site lattice, such as for the Twisted\nEguchi-Kawai model (TEK). We show that performing only over-relaxation (OR)\nupdates of the gauge links is a valid simulation algorithm for the Fabricius\nand Haan formulation of this model, and that this decorrelates observables\nfaster than using heat-bath updates. We consider two different methods of\nimplementing the OR update: either updating the whole $SU(N)$ matrix at once,\nor iterating through $SU(2)$ subgroups of the $SU(N)$ matrix, we find the same\ncritical exponent in both cases, and only a slight difference between the two."
    },
    {
        "anchor": "Testing the event-chain algorithm in asymptotically free models: We apply the event-chain algorithm proposed by Bernard, Krauth and Wilson in\n2009 to toy models of lattice QCD. We give a formal prove of stability of the\nalgorithm. We study its performance at the example of the massive Gaussian\nmodel on the square and the simple cubic lattice, the $O(3)$-invariant\nnon-linear $\\sigma$-model and the $SU(3) \\times SU(3)$ principle chiral model\non the square lattice. In all these cases we find that critical slowing down is\nessentially eliminated.",
        "positive": "Lattice implementation of Abelian gauge theories with Chern-Simons\n  number and an axion field: Real time evolution of classical gauge fields is relevant for a number of\napplications in particle physics and cosmology, ranging from the early Universe\nto dynamics of quark-gluon plasma. We present a lattice formulation of the\ninteraction between a $shift$-symmetric field and some $U(1)$ gauge sector,\n$a(x)\\tilde{F}_{\\mu\\nu}F^{\\mu\\nu}$, reproducing the continuum limit to order\n$\\mathcal{O}(dx_\\mu^2)$ and obeying the following properties: (i) the system is\ngauge invariant and (ii) shift symmetry is exact on the lattice. For this end\nwe construct a definition of the {\\it topological number density} $Q =\n\\tilde{F}_{\\mu\\nu}F^{\\mu\\nu}$ that admits a lattice total derivative\nrepresentation $Q = \\Delta_\\mu^+ K^\\mu$, reproducing to order\n$\\mathcal{O}(dx_\\mu^2)$ the continuum expression $Q = \\partial_\\mu K^\\mu\n\\propto \\vec E \\cdot \\vec B$. If we consider a homogeneous field $a(x) = a(t)$,\nthe system can be mapped into an Abelian gauge theory with Hamiltonian\ncontaining a Chern-Simons term for the gauge fields. This allow us to study in\nan accompanying paper the real time dynamics of fermion number non-conservation\n(or chirality breaking) in Abelian gauge theories at finite temperature. When\n$a(x) = a(\\vec x,t)$ is inhomogeneous, the set of lattice equations of motion\ndo not admit however a simple explicit local solution (while preserving an\n$\\mathcal{O}(dx_\\mu^2)$ accuracy). We discuss an iterative scheme allowing to\novercome this difficulty."
    },
    {
        "anchor": "A Fresh Look at the Chemical Potential on the Lattice: Lattice techniques are the most reliable ones to investigate the QCD phase\ndiagram in the temperature-baryon density (chemical potential) plane. These\ntechniques are, however, well-known to be saddled with a variety of problems at\nnonzero density. I address here the old question of placing the baryonic\n(quark) chemical potential on the lattice and point out its important\nconsequences for the current and future experimental searches of the QCD\ncritical point.",
        "positive": "Lattice QCD study of the radiative decays $J/\u03c8\\to \u03b7_c\u03b3$ and\n  $h_c\\to \u03b7_c\u03b3$: We present the results of our lattice QCD study of the hadronic matrix\nelements relevant to the physical radiative $J/\\psi\\to \\eta_c\\gamma$ and\n$h_c\\to \\eta_c\\gamma$ decays. We used the twisted mass QCD action with $N_{\\rm\nf}=2$ light dynamical quarks and from the computations made at four lattice\nspacings we were able to take the continuum limit. Besides the form factors\nparameterizing the above decays we also computed: (i) the hyperfine splitting\nand obtained $\\Delta = 112\\pm 4$ MeV, (ii) the annihilation constant\n$f_{J/\\psi}$ which agrees with the one inferred from the measured\n$\\Gamma(J/\\psi \\to e^+e^-)$."
    },
    {
        "anchor": "Light Glueball masses using the Multilevel Algorithm: Following the multilevel scheme we present an error reduction algorithm for\nextracting glueball masses from monte-carlo simulations of pure SU(3) lattice\ngauge theory. We look at the two lightest states viz. the $0^{++}$ and\n$2^{++}$. Our method involves looking at correlations between large Wilson\nloops and does not require any smearing of links. The error bars we obtain are\nat the moment comparable to those obtained using smeared operators. We also\npresent a comparison of our method with the naive method.",
        "positive": "Non-perturbative determination of improvement coefficients using\n  coordinate space correlators in $N_f=2+1$ lattice QCD: We determine quark mass dependent order $a$ improvement terms of the form\n$b_Jam$ for non-singlet scalar, pseudoscalar, vector and axialvector currents\nusing correlators in coordinate space on a set of CLS ensembles. These have\nbeen generated employing non-perturbatively improved Wilson Fermions and the\ntree-level L\\\"uscher-Weisz gauge action at $\\beta = 3.4, 3.46, 3.55$ and $3.7$,\ncorresponding to lattice spacings ranging from $a \\approx 0.085$ fm down to\n$0.05$ fm. In the $N_f=2+1$ flavour theory two types of improvement\ncoefficients exist: $b_J$, proportional to non-singlet quark mass combinations,\nand $\\bar{b}_J$ (or $\\tilde{b}_J$), proportional to the trace of the quark mass\nmatrix. Combining our non-perturbative determinations with perturbative\nresults, we quote Pad\\'e approximants parameterizing the $b_J$ improvement\ncoefficients within the above window of lattice spacings. We also give\npreliminary results for $\\tilde{b}_J$ at $\\beta=3.4$."
    },
    {
        "anchor": "Heavy Quark Physics in Nf=2 QCD: We present a preliminary analysis of the heavy-heavy spectrum and heavy-light\ndecay constants in full QCD, using a tadpole-improved SW quark action and an\nRG-improved gauge action on a 16^3 x 32 lattice with four sea quark masses\ncorresponding to m_pi/m_rho = 0.8, 0.75, 0.7, 0.6 and a^-1 = 1.3 GeV. We focus\nparticularly on the effect of sea quarks on these observables.",
        "positive": "Strong-Coupling Lattice QCD on Anisotropic Lattices: Anisotropic lattice spacings are mandatory to reach the high temperatures\nwhere chiral symmetry is restored in the strong coupling limit of lattice QCD.\nHere, we propose a simple criterion for the nonperturbative renormalisation of\nthe anisotropy coupling in strongly-coupled SU($N$) or U($N$) lattice QCD with\nmassless staggered fermions. We then compute the renormalised anisotropy, and\nthe strong-coupling analogue of Karsch's coefficients (the running anisotropy),\nfor $N=3$. We achieve high precision by combining diagrammatic Monte Carlo and\nmulti-histogram reweighting techniques. We observe that the mean field\nprediction in the continuous time limit captures the nonperturbative scaling,\nbut receives a large, previously neglected correction on the unit prefactor.\nUsing our nonperturbative prescription in place of the mean field result, we\nobserve large corrections of the same magnitude to the continuous time limit of\nthe static baryon mass, and of the location of the phase boundary associated\nwith chiral symmetry restoration. In particular, the phase boundary, evaluated\non different finite lattices, has a dramatically smaller dependence on the\nlattice time extent. We also estimate, as a byproduct, the pion decay constant\nand the chiral condensate of massless SU(3) QCD in the strong coupling limit at\nzero temperature."
    },
    {
        "anchor": "Numerical analysis of the spectrum of the Dirac operator in\n  four-dimensional SU(2) gauge fields: Two numerical algorithms for the computation of eigenvalues of Dirac\noperators in lattice gauge theories are described: one is an accelerated\nconjugate gradient method, the other one a standard Lanczos method. Results\nobtained by Cullum's and Willoughby's variant of the Lanczos method (whose\nconvergence behaviour is closely linked with the local spectral density) are\npresented for euclidean Wilson fermions in quenched and unquenched SU(2) gauge\nfields. Complete spectra are determined on lattices up to $8^3 \\cdot 12$, and\nwe derive numerical values for fermionic determinants and results for spectral\ndensities.",
        "positive": "Electromagnetic finite-size effects to the hadronic vacuum polarisation: In order to reach (sub-)per cent level precision in lattice calculations of\nthe hadronic vacuum polarisation, isospin breaking corrections must be\nincluded. This requires introducing QED on the lattice, and the associated\nfinite-size effects are potentially large due to the absence of a mass gap.\nThis means that the finite-size effects scale as an inverse polynomial in $L$\nrather than being exponentially suppressed. Considering the\n$\\mathcal{O}(\\alpha)$ corrected hadronic vacuum polarisation in\nQED$_{\\mathrm{L}}$ with scalar QED as an effective theory, we show that the\nfirst possible term, which is of order $1/L^{2}$, vanishes identically so that\nthe finite-size effects start at order $1/L^{3}$. This cancellation is\nunderstood from the neutrality of the currents involved, and we show that this\ncancellation is universal by also including form factors for the pions. We find\ngood numerical agreement with lattice perturbation theory calculations, as well\nas, up to exponentially suppressed terms, scalar QED lattice simulations."
    },
    {
        "anchor": "One loop matching factors for improved staggered four-fermion operators\n  with improved glue: We present results for matching factors for staggered four-fermion operators\nconstructed using HYP-smeared fat links both in the action and the operators.\n  We use perturbation theory to calculate the matching factors and work to\none-loop order. The new feaure of this work is the use of the Symanzik-improved\ngauge action, as opposed to the Wilson gauge action. Our results are needed for\nour ongoing calculation of weak matrix elements using HYP-smeared staggered\nvalence quarks and operators on MILC lattices. We give explicit results for\nmatching factors of the operator needed to calculate $B_K$. We compare the\nimpact of the improvement of the gauge action on one-loop coefficients with\nthat of mean-field improvement of the operators.",
        "positive": "Exact Chiral Fermions and Finite Density on Lattice: Any mu^2-divergence is shown analytically to be absent for a class of actions\nfor Overlap and Domain Wall Fermions with nonzero chemical potential. All such\nactions are, however, shown to violate the chiral invariance. While the\nparameter M of these actions can be shown to be irrelevant in the continuum\nlimit, as expected, it is shown numerically that the continuum limit can be\nreached with relatively coarser lattices for M in the range of 1.5-1.6."
    },
    {
        "anchor": "Glueball Spins in $ D=3$ Yang-Mills: We determine spins of more than 100 low lying glueball states in $D=2+1$\ndimensional $SU(4)$ gluodynamics by a lattice calculation. We go up to $J=8$ in\nthe spin value. We compare the resulting spectrum with predictions of the\nAxionic String Ansatz (ASA). We find a perfect match for 39 lightest states,\ncorresponding to the first four string levels. In particular, this resolves\ntensions between the ASA predictions and earlier spin determinations. The\nobserved spins of heavier glueballs are also in a good agreement with the ASA.\nWe did not identify any sharp tension between lattice data and the ASA, but\nmore work is needed to fully test the ASA predictions for the spins of 64\nstates at the fifth string level.",
        "positive": "On Scale Determination in Lattice QCD with Dynamical Quarks: Dependence of a/r_c (inverse Sommer parameter in units of lattice spacing a)\non am_q (quark mass in lattice unit) has been observed in all lattice QCD\nsimulations with sea quarks including the ones with improved actions. How much\nof this dependence is a scaling violation has remained an intriguing question.\nOur approach has been to investigate the issue with an action with known\nlattice artifacts, i.e., the standard Wilson quark and gauge action with\nbeta=5.6 and 2 degenerate flavors of sea quarks on 16^3 times 32 lattices. In\norder to study in detail the sea quark mass dependence, measurements are\ncarried out at eight values of the PCAC quark mass values am_q from about 0.07\nto below 0.015. Though scaling violations may indeed be present for relatively\nlarge am_q, a consistent scenario at sufficiently small am_q seems to emerge in\nthe mass-independent scheme where for a fixed beta, 1/r_0 and sqrt{sigma} have\nlinear dependence on m_q as physical effects similar to the quark mass\ndependence of the rho mass. We present evidence for this scenario and\naccordingly extract the lattice scale (a = 0.0805(7) fm, a^{-1} = 2.45(2) GeV)\nby chiral extrapolation to the physical point."
    },
    {
        "anchor": "Polyakov Loop Behavior in Non-Extensive SU(2) Lattice Gauge Theory: In order to come closer to a realistic model of high-energy collisions, we\nsimulate SU(2) lattice gauge theory under fluctuating temperature. The\nfluctuations are Euler-Gamma distributed, leading to a canonical state\nmaximizing the Renyi and Tsallis entropy formulas. We test the random lattice\nspacing method numerically on the Polyakov Loop expectation value. The critical\ncoupling and presumably also the critical deconfinement temperature shifts\nabout 30 per cent to higher values with a realistic degree of fluctuations.",
        "positive": "Three dimensional lattice gravity as supersymmetric Yang-Mills theory: We argue that a certain twisted supersymmetric Yang-Mills theory in three\ndimensions with gauge group SU(2) possesses a set of topological observables\nwhose expectation values can be computed in a related Chern Simons theory. This\nChern Simons theory has been proposed as a definition of three dimensional\nEuclidean quantum gravity. Since the YM theory admits a discretization which\npreserves the values of topological observables we conjecture that it can be\nused as a non-perturbative definition of the quantum gravity theory."
    },
    {
        "anchor": "Real Time Simulations in Lattice Gauge Theory: I review the study of real (Minkowski) time correlators in hot, weakly\ncoupled Yang-Mills theory via lattice methods. I concentrate on the Minkowski\ntime topological susceptibility, which is related to the efficiency of baryon\nnumber violation at high temperature. It can be computed by approximating the\nIR fields as classical and solving their dynamics nonperturbatively on the\nlattice. However it is essential to include the UV degrees of freedom. Their\ninfluence can be computed perturbatively and included in the lattice model by\nthe addition of auxiliary fields.",
        "positive": "Study of Possible Proton-Antiproton Hexaquark State in Lattice QCD: We have used standard techniques of lattice quantum chromodynamics to look\nfor evidence of the spin-zero six quark flavour singlet state ($J^{PC}=0^{-+}$)\nobserved by BES Collaboration, and to determine the splitting between the mass\nof the possible proton-antiproton and the mass of two protons, its threshold.\nUsing the various interpolating fields we find indications that for\nsufficiently light quarks proton-antiproton is slightly above the $2m_{p}$\nthreshold. The lattice resonance signal of binding observed near the physical\nand continuum regimes do not support the existence of proton-antiproton state\nas a spin-zero hexaquark state."
    },
    {
        "anchor": "Topological Susceptibility under Gradient Flow: We study the impact of the Gradient Flow on the topology in various models of\nlattice field theory. The topological susceptibility $\\chi_{\\rm t}$ is measured\ndirectly, and by the slab method, which is based on the topological content of\nsub-volumes (\"slabs\") and estimates $\\chi_{\\rm t}$ even when the system remains\ntrapped in a fixed topological sector. The results obtained by both methods are\nessentially consistent, but the impact of the Gradient Flow on the\ncharacteristic quantity of the slab method seems to be different in 2-flavour\nQCD and in the 2d O(3) model. In the latter model, we further address the\nquestion whether or not the Gradient Flow leads to a finite continuum limit of\nthe topological susceptibility (rescaled by the correlation length squared,\n$\\xi^{2}$). This ongoing study is based on direct measurements of $\\chi_{\\rm\nt}$ in $L \\times L$ lattices, at $L/\\xi \\simeq 6$.",
        "positive": "Phase structure and confinement properties of noncompact gauge theories\n  II. Z(N) Wilson loop and effective noncompact model: An approach to studying lattice gauge models in the weak coupling region is\nproposed. Conceptually, it is based on the crucial role of the original Z(N)\nsymmetry and the invariant gauge group measure. As an example, we calculate an\neffective model from the compact Wilson formulation of the SU(2) gauge theory\nin $d=3D3$ dimensions at zero temperature. Confining properties and phase\nstructure of the effective model are studied in details."
    },
    {
        "anchor": "Testing the hadro-quarkonium model on the lattice: Recently the LHCb experiment found evidence for the existence of two exotic\nresonances consisting of $c\\bar{c}uud$ quarks. Among the possible\ninterpretations is the hadro-charmonium model, in which charmonium is bound\n\"within\" a light hadron. We test this idea on CLS $N_f$=2+1 lattices using the\nstatic formulation for the heavy quarks. We find that the static potential is\nmodified by the presence of a hadron such that it becomes more attractive. The\neffect is of the order of a few MeV.",
        "positive": "Lattice simulations of technicolour theories with adjoint fermions and\n  supersymmetric Yang-Mills theory: Theories with fermions in the adjoint representation have several interesting\napplications in extensions of the standard model. The conformal window for\nthese theories is of particular interest for technicolour extensions. We\npresent here our newest results for the spectrum of $N_f=2$ adjoint QCD and\ncompare them with the predictions for a conformal behaviour. The comparison\nwith supersymmetric Yang-Mills theory, investigated with the same methods, will\nhelp to distinguish more clearly the conformal and the confining scenario. The\nspectrum includes additional fermionic states that are not present in QCD. We\nprovide results for the mass of these states and discuss their phenomenological\nrelevance. In addition we have done preliminary investigations of the singlet\nscalar meson state."
    },
    {
        "anchor": "Hierarchically deflated conjugate residual: We present a progress report on a new class of multigrid solver algorithm\nsuitable for the solution of 5d chiral fermions such as Domain Wall fermions\nand the Continued Fraction overlap. Unlike HDCG \\cite{Boyle:2014rwa}, the\nalgorithm works directly on a nearest neighbour fine operator. The fine\noperator used is Hermitian indefinite, for example $\\Gamma_5 D_{dwf}$, and\nconvergence is achieved with an indefinite matrix solver such as outer\niteration based on conjugate residual. As a result coarse space representations\nof the operator remain nearest neighbour, giving an 8 point stencil rather than\nthe 81 point stencil used in HDCG. It is hoped this may make it viable to\nrecalculate the matrix elements of the little Dirac operator in an HMC\nevolution.",
        "positive": "A comparative study of overlap and staggered fermions in the Schwinger\n  model: We investigate the validity of the square rooting procedure of the staggered\ndeterminant in the context of the Schwinger model. We find some evidence that\nat fixed physical quark mass the square root of the staggered determinant\nbecomes proportional to the overlap determinant in the continuum limit. We also\nfind that at fixed lattice spacing moderate smearing dramatically improves the\nchiral behavior of staggered fermions."
    },
    {
        "anchor": "Evidence for hard chiral logarithms in quenched lattice QCD: We present the first direct evidence that quenched QCD differs from full QCD\nin the chiral ($m_q \\rightarrow 0$) limit, as predicted by chiral perturbation\ntheory, from our quenched lattice QCD simulations at $\\beta = 6/g^2 = 6.0$. We\nmeasured the spectrum of light hadrons on $16^3 \\times 64$, $24^3 \\times 64$\nand $32^3 \\times 64$, using staggered quarks of masses $m_q=0.01$, $m_q=0.005$\nand $m_q=0.0025$. The pion masses showed clear evidence for logarithmic\nviolations of the PCAC relation $m_{\\pi}^2 \\propto m_q$, as predicted by\nquenched chiral perturbation theory. The dependence on spatial lattice volume\nprecludes this being a finite size effect. No evidence was seen for such chiral\nlogarithms in the behaviour of the chiral condensate\n$\\langle\\bar{\\psi}\\psi\\rangle$.",
        "positive": "Finite temperature properties of QCD with two flavors and three, four\n  and five colors: I present a numerical study of the crossover between the low temperature\nchirally broken phase and the high temperature chirally restored phase in\n$SU(N_c)$ gauge theory with $N_c=3-5$ colors and $N_f=2$ degenerate fermion\nflavors. Fermion masses span a range of intermediate values (represented by the\nsquared ratio of pseudoscalar to vector meson masses $(m_{PS}/m_V)^2\\sim 0.25$\nto 0.63). Observables include the temperature dependent chiral condensate and\nscreening masses. At each fermion mass these quantities show nearly identical\ntemperature dependence across $N_c$."
    },
    {
        "anchor": "Finite size scaling analysis of intermittency moments in the two\n  dimensional Ising model: Finite size scaling is shown to work very well for the block variables used\nin intermittency studies on a 2-d Ising lattice. The intermittency exponents so\nderived exhibit the expected relations to the magnetic critical exponent of the\nmodel. Email contact: pesch@amoco.saclay.cea.fr",
        "positive": "Transport and Connection to Heavy-ion Collisions via Heavy Flavor Probes: The heavy ion experiments in Relativistic Heavy Ion Collider (RHIC) and Large\nHadron Collider (LHC) are going through upgrade in the next five years,\nshifting their focus more on the hard processes in the new runs. One of the\nmain goals is to draw a finer image for the quark gluon plasma (QGP). The heavy\nflavor probes , which witness the whole history of heavy ion collision are\nparticularly sensitive to test the properties of QGP formed in such collisions.\nThe lattice results for heavy flavor probes provide transport and\nphenomenological models crucial inputs to describe the experimental\nobservations like the strong suppression of the nuclear modification factor\n$R_{AA}$ and the non-zero azimuthal anisotropy at low $p_T$. In the last two\nyears we have seen significant advances in the lattice QCD studies of heavy\nflavor probes, including the in-medium quarkonium properties, the complex\nstatic quark-antiquark potential and the heavy quark diffusion from lattice\nsimulations at nonzero temperature. These achievements substantially deepen our\nunderstanding of the fate of quarkonium, the screening/unscreening of the\ncomplex potential and the temperature and quark mass dependence of the heavy\nquark diffusion in thermal medium. In these proceedings, we review recent\nresults and briefly discuss possible directions in these studies."
    },
    {
        "anchor": "Nonperturbative $O(a)$ improvement of the Wilson quark action with the\n  RG-improved gauge action using the Schr\u00f6dinger functional method: We perform a nonperturbative determination of the $O(a)$-improvement\ncoefficient $c_{\\rm SW}$ and the critical hopping parameter $\\kappa_c$ for\n$N_f$=3, 2, 0 flavor QCD with the RG-improved gauge action using the\nSchr\\\"odinger functional method. In order to interpolate $c_{\\rm SW}$ and\n$\\kappa_c$ as a function of the bare coupling, a wide range of $\\beta$ from the\nweak coupling region to the moderately strong coupling points used in\nlarge-scale simulations is studied. Corrections at finite lattice size of\n$O(a/L)$ turned out to be large for the RG-improved gauge action, and hence we\nmake the determination at a size fixed in physical units using a modified\nimprovement condition. This enables us to avoid $O(a)$ scaling violations which\nwould remain in physical observables if $c_{\\rm SW}$ determined for a fixed\nlattice size $L/a$ is used in numerical simulations.",
        "positive": "Lattice calculations and the muon anomalous magnetic moment: Anomalous magnetic moment of the muon, $a_{\\mu}=(g_{\\mu}-2)/2$, is one of the\nmost precisely measured quantities in particle physics and it provides a\nstringent test of the Standard Model. The planned improvements of the\nexperimental precision at Fermilab and at J-PARC propel further reduction of\nthe theoretical uncertainty of $a_{\\mu}$. The hope is that the efforts on both\nsides will help resolve the current discrepancy between the experimental\nmeasurement of $a_{\\mu}$ and its theoretical prediction, and potentially gain\ninsight into new physics. The dominant sources of the uncertainty in the\ntheoretical prediction of $a_{\\mu}$ are the errors of the hadronic\ncontributions. I will discuss recent progress on determination of hadronic\ncontributions to $a_{\\mu}$ from lattice calculations."
    },
    {
        "anchor": "Stable solvers for real-time Complex Langevin: This study explores the potential of modern implicit solvers for stochastic\npartial differential equations in the simulation of real-time complex Langevin\ndynamics. Not only do these methods offer asymptotic stability, rendering the\nissue of runaway solution moot, but they also allow us to simulate at\ncomparatively largeLangevin time steps, leading to lower computational cost. We\ncompare different ways of regularizing the underlying path integral and\nestimate the errors introduced due to the finite Langevin time. Based on that\ninsight, we implement benchmark (non-)thermal simulations of the quantum\nanharmonic oscillator on the canonical Schwinger-Keldysh contour of short\nreal-time extent.",
        "positive": "Lattice QCD Calculations of the Sigma Commutator: As a direct source of information on chiral symmetry breaking within QCD, the\nsigma commutator is of considerable importance. With recent advances in the\ncalculation of hadron masses within full QCD it is of interest to see whether\nthe sigma commutator can be calculated directly from the dependence of the\nnucleon mass on the input quark mass. We show that provided the correct chiral\nbehaviour of QCD is respected in the extrapolation to realistic quark masses\none can indeed obtain a fairly reliable determination of the sigma commutator\nusing present lattice data. Within two-flavour, dynamical-fermion QCD the value\nobtained lies in the range 45 to 55 MeV."
    },
    {
        "anchor": "K^0-\\bar K^0 mixing beyond the standard model and CP-violating\n  electroweak penguins in quenched QCD with exact chiral symmetry: We present results for the \\Delta S=2 matrix elements which are required to\nstudy neutral kaon mixing in the standard model (SM) and beyond (BSM). We also\nprovide leading chiral order results for the matrix elements of the electroweak\npenguin operators which give the dominant \\Delta I=3/2 contribution to direct\nCP violation in K->\\pi\\pi decays. Our calculations were performed with\nNeuberger fermions on two sets of quenched Wilson gauge configurations at\ninverse lattice spacings of approximately 2.2 GeV and 1.5 GeV. All\nrenormalizations were implemented non-perturbatively in the RI/MOM scheme,\nwhere we accounted for sub-leading operator product expansion corrections and\ndiscretization errors. We find ratios of non-SM to SM matrix elements which are\nroughly twice as large as in the only other dedicated lattice study of these\namplitudes. On the other hand, our results for the electroweak penguin matrix\nelements are in good agreement with two recent domain-wall fermion\ncalculations. As a by-product of our study, we determine the strange quark\nmass. Our main results are summarized and discussed in Sec. VII. Within our\nstatistics, we find no evidence for scaling violations.",
        "positive": "B -> D* l nu with 2+1 flavors: We present a calculation of the form factor for B -> D* l nu using a 2+1\nimproved staggered action for the light quarks (on the MILC configurations),\nand the Fermilab action for the heavy quarks. The form factor is computed at\nzero recoil using a new double ratio method which yields the form factor more\ndirectly than previous approaches."
    },
    {
        "anchor": "Lattice continuum-limit study of nucleon quasi-PDFs: The quasi-PDF approach provides a path to computing parton distribution\nfunctions (PDFs) using lattice QCD. This approach requires matrix elements of a\npower-divergent operator in a nucleon at high momentum and one generically\nexpects discretization effects starting at first order in the lattice spacing\n$a$. Therefore, it is important to demonstrate that the continuum limit can be\nreliably taken and to understand the size and shape of lattice artifacts. In\nthis work, we report a calculation of isovector unpolarized and helicity PDFs\nusing lattice ensembles with $N_f=2+1+1$ Wilson twisted mass fermions, a pion\nmass of approximately 370 MeV, and three different lattice spacings. Our\nresults show a significant dependence on $a$, and the continuum extrapolation\nproduces a better agreement with phenomenology. The latter is particularly true\nfor the antiquark distribution at small momentum fraction $x$, where the\nextrapolation changes its sign.",
        "positive": "Searching for dynamical fermion effects in UKQCD simulations: We present recent results from the UKQCD collaboration's dynamical QCD\nsimulations. This data has fixed lattice spacing but varying dynamical quark\nmass. We concentrate on searching for an unquenching signal in the mesonic mass\nspectrum where we do not find a significant effect at the quark masses\nconsidered."
    },
    {
        "anchor": "Abelian and Center Vortex Condensation in SU(3) Lattice Gauge Theory: We study the condensation of Abelian and Center vortices in SU(3) lattice\ngauge theory at finite temperature. We find that both vortices condense in the\nconfined phase of the SU(3) vacuum.",
        "positive": "Center regions as a solution to the Gribov problem of the center vortex\n  model: The center vortex model, capable of explaining confinement and chiral\nsymmetry breaking, has been plagued by the lattice equivalent of Gribov copies:\ndifferent maxima of the gauge functional lead to different predictions of the\nstring tension. It is possible to resolve this problem using center regions,\nloops evaluating to center elements, as guide for the gauge fixing procedure.\nThe success of this approach was already shown, but the algorithms came with an\narbitrary free parameter. In recent development this parameter has been fixed,\neven improving the results."
    },
    {
        "anchor": "Classification of Supersymmetric Lattice Gauge Theories by Orbifolding: We provide a general classification of supersymmetric lattice gauge theories\nthat can be obtained from orbifolding of theories with four and eight\nsupercharges. We impose at least one preserved supercharge on the lattice and\nLorentz invariance in the naive continuum limit. Starting with four\nsupercharges, we obtain one two-dimensional lattice gauge theory, identical to\nthe one already given in the literature. Starting with eight supercharges, we\nobtain a unique three-dimensional lattice gauge theory and infinitely many\ntwo-dimensional lattice theories. They can be classified according to seven\ndistinct groups, five of which have two preserved supercharges while the others\nhave only one.",
        "positive": "B meson spectrum and decay constant from Nf=2 simulations: We report on the status of an ALPHA Collaboration project to extract\nquantities for B physics phenomenology from Nf=2 lattice simulations. The\nframework is Heavy Quark Effective Theory (HQET) expanded up to the first order\nof the inverse b-quark mass. The couplings of the effective theory are\ndetermined by imposing matching conditions of observables computed in HQET with\ntheir counterpart computed in QCD. That program, based on Nf=2 simulations in a\nsmall physical volume with SF boundary conditions, is now almost finished. On\nthe other side the analysis of configurations selected from the CLS ensembles,\nin order to measure HQET hadronic matrix elements, has just started recently so\nthat only results obtained at a single lattice spacing, a=0.07 fm, will be\ndiscussed. We give our first results for the b-quark mass and for the B meson\ndecay constant."
    },
    {
        "anchor": "Ginzburg Criterion for the Chiral Transition: This report is based on the work done together with J.B. Kogut and C.G.\nStrouthos. We study a Yukawa theory with spontaneous chiral symmetry breaking\nand with a large number N of fermions near the finite temperature phase\ntransition. Critical properties in such a system can be described by the mean\nfield theory very close to the transition point. We show that the width of the\nwindow of non-trivial scaling is suppressed by a certain power of 1/N. Our\nMonte Carlo simulations confirm these analytical results. We discuss\nimplications for the chiral phase transition in QCD.",
        "positive": "Gluon and Ghost Dynamics from Lattice QCD: The two point gluon and ghost correlation functions and the three gluon\nvertex are investigated, in the Landau gauge, using lattice simulations. For\nthe two point functions, we discuss the approach to the continuum limit looking\nat the dependence on the lattice spacing and volume. The analytical structure\nof the propagators is also investigated by computing the corresponding spectral\nfunctions using an implementation of the Tikhonov regularisation to solve the\nintegral equation. For the three point function we report results when the\nmomentum of one of the gluon lines is set to zero and discuss its implications."
    },
    {
        "anchor": "Pseudoscalar decay constants from N_f=2+1+1 twisted mass lattice QCD: We present first results for the pseudoscalar decay constants $f_K$, $f_D$\nand $f_{D_s}$ from lattice QCD with N_f=2+1+1 flavours of dynamical quarks. The\nlattice simulations have been performed by the European Twisted Mass\ncollaboration (ETMC) using maximally twisted mass quarks. For the pseudoscalar\ndecay constants we follow a mixed action approach by using so called\nOsterwalder-Seiler fermions in the valence sector for strange and charm quarks.\nThe data for two values of the lattice spacing and several values of the\nup/down quark mass is analysed using chiral perturbation theory.",
        "positive": "$\u03b8$ dependence of 4D $SU(N)$ gauge theories in the large-$N$ limit: We study the large-$N$ scaling behavior of the $\\theta$ dependence of the\nground-state energy density $E(\\theta)$ of four-dimensional (4D) $SU(N)$ gauge\ntheories and two-dimensional (2D) $CP^{N-1}$ models, where $\\theta$ is the\nparameter associated with the Lagrangian topological term. We consider its\n$\\theta$ expansion around $\\theta=0$, $E(\\theta)-E(0) = {1\\over 2}\\chi\n\\,\\theta^2 ( 1 + b_2 \\theta^2 + b_4\\theta^4 +\\cdots)$ where $\\chi$ is the\ntopological susceptibility and $b_{2n}$ are dimensionless coefficients. We\nfocus on the first few coefficients $b_{2n}$, which parametrize the deviation\nfrom a simple Gaussian distribution of the topological charge at $\\theta=0$. We\npresent a numerical analysis of Monte Carlo simulations of 4D $SU(N)$ lattice\ngauge theories for $N=3,\\,4,\\,6$ in the presence of an imaginary $\\theta$ term.\nThe results provide a robust evidence of the large-$N$ behavior predicted by\nstandard large-$N$ scaling arguments, i.e. $b_{2n}= O(N^{-2n})$. In particular,\nwe obtain $b_2=\\bar{b}_2/N^2 + O(1/N^4)$ with $\\bar{b}_2=-0.23(3)$. We also\nshow that the large-$N$ scaling scenario applies to 2D $CP^{N-1}$ models as\nwell, by an analytic computation of the leading large-$N$ dependence."
    },
    {
        "anchor": "Strong-coupling lattice study for QCD phase diagram including both\n  chiral and deconfinement dynamics: We investigate the QCD phase diagram by using the strong-coupling expansion\nof the lattice QCD with one species of staggered fermion and the Polyakov loop\neffective action at finite temperature (T) and quark chemical potential (mu).\nWe derive an analytic expression of effective potential Feff including both the\nchiral (U(1)) and the deconfinement (Z_Nc) dynamics with finite coupling\neffects in the mean-field approximation. The Polyakov loop increasing rate\n(dl/dT) is found to have two peaks as a function of T for small quark masses.\nOne of them is the chiral-induced peak associated with the rapid decrease of\nthe chiral condensate. The temperature of the other peak is almost independent\nof the quark mass or chemical potential, and this peak is interpreted as the\nZ_Nc-induced peak.",
        "positive": "AVX-512 extension to OpenQCD 1.6: We publish an extension of openQCD-1.6 with AVX-512 vector instructions using\nIntel intrinsics. Recent Intel processors support extended instruction sets\nwith operations on 512-bit wide vectors, increasing both the capacity for\nfloating point operations and register memory. Optimal use of the new\ncapabilities requires reorganising data and floating point operations into\nthese wider vector units. We report on the implementation and performance of\nthe AVX-512 OpenQCD extension on clusters using Intel Knights Landing and Xeon\nScalable (Skylake) CPUs. In complete HMC trajectories with physically relevant\nparameters we observe a performance increase of 5% to 10%."
    },
    {
        "anchor": "The QCD deconfinement critical point for $N_\u03c4=8$ with $N_f=2$\n  flavours of unimproved Wilson fermions: QCD at zero baryon density in the limit of infinite quark mass undergoes a\nfirst order deconfinement phase transition at a critical temperature $T_c$\ncorresponding to the breaking of the global centre symmetry. In the presence of\ndynamical quarks this symmetry is explicitly broken. Lowering the quark mass\nthe first order phase transition weakens and terminates in a second order Z(2)\npoint. Beyond this line confined and deconfined regions are analytically\nconnected by a crossover transition. As the continuum limit is approached (i.e.\nthe lattice spacing is decreased) the region of first order transitions expands\ntowards lower masses. We study the deconfinement critical point with standard\nWilson fermions and $N_f=2$ flavours. To this end we simulate several kappa\nvalues on $N_\\tau=8$ and various aspect ratios in order to extrapolate to the\nthermodynamic limit, applying finite size scaling. We estimate if and when a\ncontinuuum extrapolation is possible.",
        "positive": "Probing for Instanton Quarks with epsilon-Cooling: We use epsilon-cooling, adjusting at will the order a^2 corrections to the\nlattice action, to study the parameter space of instantons in the background of\nnon-trivial holonomy and to determine the presence and nature of constituents\nwith fractional topological charge at finite and zero temperature for SU(2). As\nan additional tool, zero temperature configurations were generated from those\nat finite temperature with well-separated constituents. This is achieved by\n\"adiabatically\" adjusting the anisotropic coupling used to implement finite\ntemperature on a symmetric lattice. The action and topological charge density,\nas well as the Polyakov loop and chiral zero-modes are used to analyse these\nconfigurations. We also show how cooling histories themselves can reveal the\npresence of constituents with fractional topological charge. We comment on the\ninterpretation of recent fermion zero-mode studies for thermalized ensembles at\nsmall temperatures."
    },
    {
        "anchor": "Resolving-Power Quantization: Starting with a general discussion, a program is sketched for a quantization\nbased on dilations. This resolving-power quantization is simplest for scalar\nfield theories. The hope is to find a way to relax the requirement of locality\nso that the necessity to fine tune mass parameters is eliminated while\nuniversality is still preserved.",
        "positive": "Investigating BSM Models with Large Scale Separation: Mass-split systems based on a conformal infrared fixed point provide a\nlow-energy effective description of beyond the standard model systems with\nlarge scale separation. We report results of exploratory investigations with\nfour light and eight heavy flavors using staggered fermions, and up to five\ndifferent values for the light flavor mass, five different heavy flavor masses,\nand two values of the bare gauge coupling."
    },
    {
        "anchor": "Casimir effect in Yang-Mills theory: We study, for the first time, the Casimir effect in non-Abelian gauge theory\nusing first-principle numerical simulations. Working in two spatial dimensions\nat zero temperature we find that closely spaced perfect chromoelectric\nconductors attract each other with a small anomalous scaling dimension. At\nlarge separation between the conductors, the attraction is exponentially\nsuppressed by a new massive quantity, the Casimir mass, which is surprisingly\ndifferent from the lowest glueball mass. The apparent emergence of the new\nmassive scale may be a result of the backreaction of the vacuum to the presence\nof the plates as sufficiently close chromoelectric conductors induce, in a\nspace between them, a smooth crossover transition to a color deconfinement\nphase.",
        "positive": "Spectral density of the Dirac-Ginsparg-Wilson operator, chiral $U(1)_A$\n  anomaly, and analyticity in the high temperature phase of $QCD$: Using general properties of the $Q=0$ topological sector we previously argued\nthat a vector-like theory, with chiral $U(1)_A$ anomaly, and exact non-Abelian\nchiral symmetry, should exhibit divergent susceptibilities in the chiral limit,\nthe two-flavor Schwinger model being a paradigmatic example of the realization\nof this scenario. Two flavor $QCD$ at $T>T_c$ satisfies all the above\nconditions, and it is also expected that the $U(1)_A$ axial symmetry remains\neffectively broken in its high temperature phase. Therefore we would expect a\nnon-analyticity in the quark mass dependence of the free energy density, in\ncontrast with the Dilute Instanton Gas Approximation (DIGA) prediction. We\ninvestigate in this work whether the aforementioned results can also be\nreproduced making only use of standard properties of the spectral density of\nthe Dirac operator, without having to resort to general properties of the $Q=0$\ntopological sector. We show that the only way to derive a non-trivial\n$\\theta$-dependence, and an analytical free energy density in $QCD$ with two\ndegenerate flavors is that the spectral density, $\\rho\\left(\\lambda,m\\right)$,\nof the absolute value of the non-zero modes of the Dirac-Ginsparg-Wilson\noperator develops a $m^2\\delta(\\lambda)$ function in the thermodynamic limit.\nThis is the expected result in the DIGA, where interactions between instantons\nin the dilute gas are fully neglected. However, at temperatures close to $T_c$\nthe interaction between instantons should become non-negligible, and the\nsplitting from zero of the near-zero modes, which has been neglected in the\nDIGA, should be taken into account. Therefore we expect that the\n$m^2\\delta(\\lambda)$ contribution to the spectral density is no longer correct\nat these temperatures, and that the free energy density becomes a non-analytic\nfunction of the quark mass.some clarifications added"
    },
    {
        "anchor": "Nonperturbative determination of $\u03b2$ functions for SU(3) gauge\n  theories with 10 and 12 fundamental flavors using domain wall fermions: Nonperturbative lattice field theory simulations provide a systematic\nframework to investigate properties of conformal systems at strong couplings.\nThese simulations can be performed using different lattice discretizations.\nHere we present numerical results for the step scaling beta function in SU(3)\ngauge theories with ten and twelve fundamental flavors. We calculate the\nrenormalized $\\beta$ function in the finite volume gradient flow\nrenormalization scheme. Using M\\\"obius domain wall fermions with Symanzik gauge\naction, Zeuthen gradient flow, and perturbative tree-level improvement, we\nimplement a fully $O(a^2)$ Symanzik improved set-up and demonstrate its\nadvantages. We compare our findings to existing results in the literature. For\nthe ten flavor system we observe excellent agreement with the domain wall\nstep-scaling function calculated by Chiu for the range in $g_c^2$ where our\ndata overlap. In the case of the twelve flavor system, our $O(a^2)$ Symanzik\nimproved set-up predicts a conformal infrared fixed point around $g_c^2 \\sim\n5.5$ in the $c=0.25$ scheme, which is presently in tension with staggered\nfermion results in the literature. We consider possible reasons for the\ndiscrepancy.",
        "positive": "The QCD phase diagram for small densities from imaginary chemical\n  potential: We present results on the QCD phase diagram for mu_B <= pi T. Our simulations\nare performed with an imaginary chemical potential mu_I for which the fermion\ndeterminant is positive. On an 8^3 x 4 lattice with 2 flavors of staggered\nquarks, we map out the phase diagram and identify the pseudo-critical\ntemperature T_c(mu_I). For mu_I/T <= pi/3, this is an analytic function, whose\nTaylor expansion is found to converge rapidly, with truncation errors far\nsmaller than statistical ones. The truncated series may then be continued to\nreal mu, yielding the corresponding phase diagram for mu_B <~ 500 MeV. This\napproach provides control over systematics and avoids reweighting. We compare\nit with other recent work."
    },
    {
        "anchor": "Lattice QCD Study of Transverse-Momentum Dependent Soft Function: In this work, we perform a lattice QCD study of the intrinsic,\nrapidity-independent soft function within the framework of large momentum\neffective theory. The computation is carried out using a gauge ensemble of\n$N_f=2+1+1$ clover-improved twisted mass fermion. After applying an appropriate\nrenormalization procedure and the removal of significant higher-twist\ncontamination, we obtain the intrinsic soft function that is comparable to the\none-loop perturbative result at large external momentum. The determination of\nthe nonperturbative soft function from first principles is crucial to sharpen\nour understanding of the processes with small transverse momentum such as the\nDrell-Yan production and the semi-inclusive deep inelastic scattering.\nAdditionally, we calculate the Collins-Soper evolution kernel using the\nquasi-transverse-momentum-dependent wave function as input.",
        "positive": "Some Considerations on Lattice Gauge Fixing: Some problems related to Gribov copies in lattice gauge-fixing and their\npossible solution are discussed."
    },
    {
        "anchor": "Dependence of the propagators on the sampling of Gribov copies inside\n  the first Gribov region of Landau gauge: Beyond perturbation theory the number of gauge copies drastically increases\ndue to the Gribov-Singer ambiguity. Any way of treating them defines, in\nprinciple, a new, non-perturbative gauge, and the gauge-dependent correlation\nfunctions can vary between them. Herein various such gauges will be constructed\nas completions of the Landau gauge inside the first Gribov region. The\ndependence of the propagators and the running coupling on these gauges will be\nstudied for SU(2) Yang-Mills theory in two, three, and four dimensions using\nlattice gauge theory, and for a wide range of lattice parameters. While the\ngluon propagator is rather insensitive to the choice, the ghost propagator and\nthe running coupling show a stronger dependence. It is also found that the\ninfluence of lattice artifacts is larger than in minimal Landau gauge.",
        "positive": "Gluon propagators in the deep IR region and non-Abelian dual\n  superconductivity for SU(3) Yang-Mills: We have presented non-Abelian dual superconductivity picture in the SU(3)\nYang-Mills(YM) theory, and shown evidences such as the restricted U(2)-field\ndominance and the non-Abelian magnetic monopole dominance in the string\ntension. To establish the dual superconductivity picture, the dual Meissner\neffect in Yang-Mills theory must be examined, and we also presented the\nevidence of non-Abelian dual Meissner effect by measuring chromo-electric flux\ntube in the last lattice conferences.\n  In this talk, by applying a new formulation of the YM theory on a lattice,\nthe we further investigate the non-Abelian dual Meissner effect for SU(3) YM\ntheory through correlation function. We examine non-abelian magnetic monopole\ncurrents as well as color flux created by the quark-antiquark source."
    },
    {
        "anchor": "Universal critical behavior and the transition temperature in\n  (2+1)-flavor QCD: We discuss the universal critical behavior in (2+1)-flavor QCD by analyzing\nlattice data from improved staggered fermions generated by the HotQCD\nCollaboration. We present recent results from two different lattice\ndiscretizations and various lattice spacings ($N_\\tau=6,8,12$) at fixed\nphysical strange quark mass ($m_s$) but varying light quark mass ($m_l$). We\nfind that the chiral order-parameter, i.e. the chiral condensate, shows the\nexpected universal scaling that is associated with the critical point in the\nchiral limit already for light quark masses $m_l/m_s \\lsim 0.05$. From an\nanalysis of the disconnected chiral susceptibility we estimate a preliminary\nvalue of the QCD transition temperature.",
        "positive": "The fermion determinant and the chiral gauge theory on a lattice: Considering as an example a simple lattice ansatz for the chiral fermion\ndeterminant, we demonstrate that even very mild violation of gauge invariance\nby the determinant at finite lattice spacing leads to the need for another\nscale in the full gauge theory. This new scale is much grater than the lattice\nspacing and is associated with the gauge variables."
    },
    {
        "anchor": "The strong coupling regime of twelve flavors QCD: We summarize the results recently reported in Ref.[1] [A. Deuzeman, M.P.\nLombardo, T. Nunes da Silva and E. Pallante,\"The bulk transition of QCD with\ntwelve flavors and the role of improvement\"] for the SU(3) gauge theory with\nNf=12 fundamental flavors, and we add some numerical evidence and theoretical\ndiscussion. In particular, we study the nature of the bulk transition that\nseparates a chirally broken phase at strong coupling from a chirally restored\nphase at weak coupling. When a non-improved action is used, a rapid crossover\nis observed at small bare quark masses. Our results confirm a first order\nnature for this transition, in agreement with previous results we obtained\nusing an improved action. As shown in Ref.[1], when improvement of the action\nis used, the transition is preceded by a second rapid crossover at weaker\ncoupling and an exotic phase emerges, where chiral symmetry is not yet broken.\nThis can be explained [1] by the non hermiticity of the improved lattice\nTransfer matrix, arising from the competition of nearest-neighbor and\nnon-nearest neighbor interactions, the latter introduced by improvement and\nbecoming increasingly relevant at strong coupling and coarse lattices. We\nfurther comment on how improvement may generally affect any lattice system at\nstrong coupling, be it graphene or non abelian gauge theories inside or\nslightly below the conformal window.",
        "positive": "Off-forward gluonic structure of vector mesons: The spin-independent and transversity generalised form factors (GFFs) of the\n$\\phi$ meson are studied using lattice QCD calculations with light quark masses\ncorresponding to a pion mass $m_\\pi\\sim450(5)$ MeV. One transversity and three\nspin-independent GFFs related to the lowest moments of leading-twist\nspin-independent and transversity gluon distributions are obtained at six\nnon-zero values of the momentum transfer up to 1.2 GeV$^2$. These quantities\nare compared with the analogous spin-independent quark GFFs and the\nelectromagnetic form factors determined on the same lattice ensemble. The\nresults show quantitative distinction between the spatial distribution of\ntransversely polarised gluons, unpolarised gluons, and quarks, and point the\nway towards further investigations of the gluon structure of nucleons and\nnuclei."
    },
    {
        "anchor": "Lattice Gauge Theories at the Energy Frontier: This White Paper has been prepared as a planning document for the Division of\nHigh Energy Physics of the U. S. Department of Energy. Recent progress in\nlattice-based studies of physics beyond the standard model is summarized, and\nmajor current goals of USQCD research in this area are presented. Challenges\nand opportunities associated with the recently discovered 126 GeV Higgs-like\nparticle are highlighted. Computational resources needed for reaching important\ngoals are described. The document was finalized on February 11, 2013 with\nreferences that are not aimed to be complete, or account for an accurate\nhistorical record of the field.",
        "positive": "Efficient Hadronic Operators in Lattice Gauge Theory: We propose the study of non-local gauge invariant operators to obtain an\nuncontaminated ground state for hadrons. The efficiency of the operators is\nshown by looking at the wave function of the first excited state, which has a\nnode as a function of spatial extent of the operator."
    },
    {
        "anchor": "A formulation of domain-wall fermions in the Schr\u00f6dinger functional: We present a formulation of domain-wall fermions in the Schr\\\"odinger\nfunctional by following a universality argument. To examine the formulation, we\nnumerically investigate the spectrum of the free operator and perform a\none-loop analysis to confirm universality and renormalizability. We also study\nthe breaking of the Ginsparg-Wilson relation to understand the structure of\nchiral symmetry breaking from two sources: The bulk and boundary. Furthermore,\nwe discuss the lattice artifacts of the step scaling function by comparing with\nother fermion discretizations.",
        "positive": "Lattice formulation of chiral gauge theories: We present a general formulation of chiral gauge theories, which admits Dirac\noperators with more general spectra, reveals considerably more possibilities\nfor the structure of the chiral projections, and nevertheless allows\nappropriate realizations. In our analyses we use two forms of the correlation\nfunctions which both also apply in the presence of zero modes and for any value\nof the index. To account properly for the conditions on the bases the concept\nof equivalence classes of pairs of them is introduced. The behaviors under\ngauge transformations and under CP transformations are unambiguously derived."
    },
    {
        "anchor": "Chiral Analysis of the Generalized Form Factors of the Nucleon: We apply the methods of Chiral Perturbation Theory to the analysis of the\nfirst moments of the Generalized Parton Distributions in a Nucleon, usually\nknown as generalized form factors. These quantities are currently also under\ninvestigation in Lattice QCD analyses of baryon structure, providing simulation\nresults at large quark masses to be extrapolated to the \"real world\" via Chiral\nEffective Field Theory. We have performed a leading-one-loop calculation in the\ncovariant framework of Baryon Chiral Perturbation Theory (BChPT), predicting\nboth the momentum and the quark-mass dependence for all the vector and axial\n(generalized) form factors. In particular we discuss the results for the limit\nof vanishing four-momentum transfer where the GPD-moments reduce to the well\nknown moments of Parton Distribution Functions (PDFs). We fit our results to\navailable lattice QCD data, extrapolating down to the physical point. We\nconclude by presenting outstanding results from a combined fit to different\nGPDs-moments.",
        "positive": "Study of topological quantities of lattice QCD by a modified Wasserstein\n  generative adversarial network: A modified Wasserstein generative adversarial network (M-WGAN) is proposed to\nstudy the distribution of the topological charge in lattice QCD based on the\nMonte Carlo (MC) simulations. We construct new generator and discriminator in\nM-WGAN to support the generation of high-quality distribution. Our results show\nthat the M-WGAN scheme of the Machine learning should be helpful for us to\ncalculate efficiently the 1D distribution of topological charge compared with\nthe results by the MC simulation alone."
    },
    {
        "anchor": "Gauge/gravity duality and lattice simulations of one dimensional SYM\n  with sixteen supercharges: We study the gauge/gravity duality for supersymmetric SU(N) Yang-Mills theory\nin 1+0 dimension with sixteen supercharges using lattice simulations. The\nconjectured duality states that the gravity side is described by N D0-branes in\ntype IIA superstring at large N, and the thermal gauge theory reproduces the\nblack hole thermodynamics at low temperature. In this paper, we explain the\nSugino lattice action used in the simulations in detail, and examine the\nsupersymmetric Ward-Takahashi identity to confirm the restoration of\nsupersymmetry in the continuum limit. We also estimate the internal energy of\nthe black hole from the lattice results for N=14,32, and find that it smoothly\napproaches the prediction of the gravity side as the temperature decreases.",
        "positive": "Bounds on the renormalized couplings in an SU(2)_L \\otimes SU(2)_R\n  symmetric Yukawa model: The vacuum stability lower bound on the mass of the Higgs boson is\nnumerically investigated in an $SU(2)_L \\otimes SU(2)_R$ symmetric Yukawa\nmodel, which describes two heavy degenerate fermion doublets in the limit of\nvanishing gauge couplings. Good agreement with perturbation theory is found,\nalthough the couplings are strong. The upper bound on the fermion mass and\nrenormalized Yukawa coupling is also determined in the part of bare parameter\nspace where reflection positivity has been proven."
    },
    {
        "anchor": "Simulating Wilson fermions without critical slowing down: We present a simulation algorithm for Wilson fermions based on the exact\nhopping expansion of the fermion action. The algorithm essentially eliminates\ncritical slowing down by sampling the fermionic two-point correlation function\nand it allows simulations directly in the massless limit. As illustrative\nexamples, the algorithm is applied to the Gross-Neveu and the Schwinger model,\nthe latter in the strong coupling limit.",
        "positive": "Further lattice evidence for a large re-scaling of the Higgs condensate: Using a high-statistics lattice simulation of the Ising limit of $(\\lambda\n\\Phi^4)_4$ theory, we have measured the susceptibility and propagator in the\nbroken phase. We confirm our earlier finding of a discrepancy between the field\nre-scaling implied by the propagator data and that implied by the\nsusceptibility. The discrepancy becomes {\\it worse} as one goes closer to the\ncontinuum limit; thus, it cannot be explained by residual perturbative effects.\nThe data are consistent with an unconventional description of symmetry breaking\nand ``triviality'' in which the re-scaling factor for the finite-momentum\nfluctuations tends to unity, but the re-scaling factor for the condensate\nbecomes larger and larger as one approaches the continuum limit. In the\nStandard Model this changes the interpretation of the Fermi-constant scale and\nits relation to the Higgs mass."
    },
    {
        "anchor": "Damaging 2D Quantum Gravity: We investigate numerically the behaviour of damage spreading in a Kauffman\ncellular automaton with quenched rules on a dynamical $\\phi^3$ graph, which is\nequivalent to coupling the model to discretized 2D gravity. The model is\ninteresting from the cellular automaton point of view as it lies midway between\na fully quenched automaton with fixed rules and fixed connectivity and a\n(soluble) fully annealed automaton with varying rules and varying connectivity.\nIn addition, we simulate the automaton on a fixed $\\phi^3$ graph coming from a\n2D gravity simulation as a means of exploring the graph geometry.",
        "positive": "Two-Color QCD with Chiral Chemical Potential: The phase diagram of two-color QCD with a chiral chemical potential is\nstudied on the lattice. The focus is on the confinement/deconfinement phase\ntransition and the breaking/restoration of chiral symmetry. The simulations are\ncarried out with dynamical staggered fermions without rooting. The dependence\nof the Polyakov loop, the chiral condensate and the corresponding\nsusceptibilities on the chiral chemical potential and the temperature are\npresented."
    },
    {
        "anchor": "The Schwinger Model with Perfect Staggered Fermions: We construct a new perfect action for free staggered fermions, which is more\nlocal than the one obtained from the standard block average scheme. This pays\noff in superior properties after a short ranged truncation. This action is\n``gauged by hand'' and tested in Schwinger model simulations by means of a new\nvariant of hybrid MC. Using ``fat links'' for the gauge field, we obtain a tiny\n``pion'' mass down to \\beta \\approx 1.5, and the ``eta'' mass follows very\nclosely the prediction of asymptotic scaling.",
        "positive": "Mixed Model of Induced QCD: The problems with the $Z_N$ symmetry breaking in the induced QCD are\nanalyzed. We compute the Wilson loops in the strong coupling phase, but we do\nnot find the $Z_N$ symmetry breaking, for arbitrary potential. We suggest to\nbypass this problem by adding to the model a heavy fermion field in a\nfundamental representation of $ SU(N) $. Remarkably, the model still can be\nsolved exactly by the Rieman-Hilbert method, for arbitrary number $N_f$ of\nflavors. At $ N_f \\ll N \\rightarrow \\infty $ there is a new regime, with two\nvacuum densities. The $Z_N$ symmetry breaking density satisfies the linear\nintegral equation, with the kernel, depending upon the old density. The\nsymmetry breaking requires certain eigenvalue condition, which takes some extra\nparameter adjustment of the scalar potential."
    },
    {
        "anchor": "Asymptotic Scaling and Monte Carlo Data: It is a generally known problem that the behaviour predicted from\nperturbation theory for asymptotically free theories like QCD, i.e. asymptotic\nscaling, has not been observed in Monte Carlo simulations when the series is\nexpressed in terms of the bare coupling g_0. This discrepancy has been\nexplained in the past with the poor convergence properties of the perturbative\nseries in the g_0. An alternative point of view, called Lattice-Distorted\nPerturbation Theory proposes that lattice artifacts due to the finiteness of\nthe lattice spacing, a, cause the disagreement between Monte Carlo data and\nperturbative scaling. Following this alternative scenario, we fit recent\nquenched data from different observables to fitting functions that include\nthese cut-off effects, confirming that the lattice data are well reproduced by\ng_0-PT with the simple addition of terms O(a^n).",
        "positive": "Vacuum correlators at short distances from lattice QCD: Non-perturbatively computing the hadronic vacuum polarization at large photon\nvirtualities and making contact with perturbation theory enables a precision\ndetermination of the electromagnetic coupling at the $Z$ pole, which enters\nglobal electroweak fits. In order to achieve this goal ab initio using lattice\nQCD, one faces the challenge that, at the short distances which dominate the\nobservable, discretization errors are hard to control. Here we address\nchallenges of this type with the help of static screening correlators in the\nhigh-temperature phase of QCD, yet without incurring any bias. The idea is\nmotivated by the observations that (a) the cost of high-temperature simulations\nis typically much lower than their vacuum counterpart, and (b) at distances\n$x_3$ far below the inverse temperature $1/T$, the operator-product expansion\nguarantees the thermal correlator of two local currents to deviate from the\nvacuum correlator by a relative amount that is power-suppressed in $(x_3\\:T)$.\nThe method is first investigated in lattice perturbation theory, where we point\nout the appearance of an O$(a^2 \\log(1/a))$ lattice artifact in the vacuum\npolarization with a prefactor that we calculate. It is then applied to\nnon-perturbative lattice QCD data with two dynamical flavors of quarks. Our\nlattice spacings range down to 0.049 fm for the vacuum simulations and down to\n0.033 fm for the simulations performed at a temperature of 250 MeV."
    },
    {
        "anchor": "Decorrelation of the topological charge in tempered simulations of full\n  QCD: The improvement of simulations of QCD with dynamical Wilson fermions by\ncombining the Hybrid Monte Carlo algorithm with parallel tempering is studied.\nAs an indicator for decorrelation the topological charge is used.",
        "positive": "$N\u03a9$ dibaryon from lattice QCD near the physical point: The nucleon($N$)-Omega($\\Omega$) system in the S-wave and spin-2 channel\n($^5$S$_2$) is studied from the (2+1)-flavor lattice QCD with nearly physical\nquark masses ($m_\\pi \\simeq 146$~MeV and $m_K \\simeq 525$~MeV). The\ntime-dependent HAL QCD method is employed to convert the lattice QCD data of\nthe two-baryon correlation function to the baryon-baryon potential and\neventually to the scattering observables. The $N\\Omega$($^5$S$_2$) potential,\nobtained under the assumption that its couplings to the D-wave octet-baryon\npairs are small, is found to be attractive in all distances and to produce a\nquasi-bound state near unitarity: In this channel, the scattering length, the\neffective range and the binding energy from QCD alone read $a_0=\n5.30(0.44)(^{+0.16}_{-0.01})$~fm, $r_{\\rm eff} =\n1.26(0.01)(^{+0.02}_{-0.01})$~fm, $B = 1.54(0.30)(^{+0.04}_{-0.10})$~MeV,\nrespectively. Including the extra Coulomb attraction, the binding energy of\n$p\\Omega^-$($^5$S$_2$) becomes $B_{p\\Omega^-} =\n2.46(0.34)(^{+0.04}_{-0.11})$~MeV. Such a spin-2 $p\\Omega^-$ state could be\nsearched through two-particle correlations in $p$-$p$, $p$-nucleus and\nnucleus-nucleus collisions."
    },
    {
        "anchor": "Quenched Chiral Logs, the $\u03b7'$ Mass, and the Hairpin Diagram: Limits on the size of quenched chiral logs in the pion mass for Wilson\nfermions are investigated. The smallness of chiral logs is shown to be a result\nof the suppression of the hairpin diagram for small $p^2$, such that the value\nof the hairpin on the pion mass shell is much smaller than the physical\n$m_{\\eta'}^2$. A direct calculation of the topological susceptibility from the\nsame data gives $m_{\\eta'}\\approx 1$ GeV.",
        "positive": "Probing the topological structure of the QCD vacuum with overlap\n  fermions: Overlap fermions implement exact chiral symmetry on the lattice and are thus\nan appropriate tool for investigating the chiral and topological structure of\nthe QCD vacuum. We study various chiral and topological aspects on\nLuescher-Weisz-type quenched gauge field configurations using overlap fermions\nas a probe. Particular emphasis is placed upon the analysis of the spectral\ndensity and the localisation properties of the eigenmodes as well as on the\nlocal structure of topological charge fluctuations."
    },
    {
        "anchor": "Finite temperature phase transition with two flavors of improved Wilson\n  fermions: The critical temperature is computed for N_f = 2 dynamical flavors of\nnonperturbatively improved Wilson fermions. The new simulations are performed\non lattices 40^3 x 14 with lattice spacing and pion mass about 0.08 fm and 200\nMeV, respectively. We find the deconfinement and chiral phase transitions to\ncoincide within numerical precision. Our results are in broad agreement with a\nsecond order phase transition in the chiral limit. The critical temperature at\nthe physical quark mass is found to be T_c = 172(3)(6) MeV.",
        "positive": "A non-perturbative determination of Z_V and b_V for O(a) improved\n  quenched and unquenched Wilson fermions: By considering the local vector current between nucleon states and imposing\ncharge conservation we determine, for $O(a)$ improved Wilson fermions, its\nrenormalisation constant and quark mass improvement coefficient. The\ncomputation is performed for both quenched and two flavour unquenched fermions."
    },
    {
        "anchor": "Update on onium masses with three flavors of dynamical quarks: We update results presented at Lattice 2005 on charmonium masses. New\nensembles of gauge configurations with 2+1 flavors of improved staggered quarks\nhave been analyzed. Statistics have been increased for other ensembles. New\nresults are also available for P-wave mesons and for bottomonium on selected\nensembles.",
        "positive": "Application of the $O(N)$-Hyperspherical Harmonics to the Study of the\n  Continuum Limits of One-Dimensional $\u03c3$-Models and to the Generation of\n  High-Temperature Expansions in Higher Dimensions: In this talk we present the exact solution of the most general\none-dimensional $O(N)$-invariant spin model taking values in the sphere\n$S^{N-1}$, with nearest-neighbour interactions, and we discuss the possible\ncontinuum limits. All these results are obtained using a high-temperature\nexpansion in terms of hyperspherical harmonics. Applications in higher\ndimensions of the same technique are then discussed."
    },
    {
        "anchor": "Estimates for the lightest baryon masses in $\\mathcal{N} = 1$\n  supersymmetric Yang-Mills theory: $\\mathcal{N} = 1$ supersymmetric Yang-Mills theory describes gluons\ninteracting with gluinos, which are spin-$\\frac{1}{2}$ Majorana particles in\nthe adjoint representation of the gauge group. In addition to glueballs and\nmesonic bound states, the theory contains color neutral bound states of three\ngluinos, which are analogous to baryons in QCD. We calculate their correlation\nfunctions, involving ``sunset diagrams'' and ``spectacle diagrams'',\nnumerically for gauge group SU(2) and present an update on the estimates for\nthe lowest masses.",
        "positive": "Two-color QCD at high density: QCD at high chemical potential has interesting properties such as\ndeconfinement of quarks. Two-color QCD, which enables numerical simulations on\nthe lattice, constitutes a laboratory to study QCD at high chemical potential.\nAmong the interesting properties of two-color QCD at high density is the\ndiquark condensation, for which we present recent results obtained on a finer\nlattice compared to previous studies. The quark propagator in two-color QCD at\nnon-zero chemical potential is referred to as the Gor'kov propagator. We\nexpress the Gor'kov propagator in terms of form factors and present recent\nlattice simulation results."
    },
    {
        "anchor": "SU(3) lattice QCD study for octet and decuplet baryon spectra: The spectra of octet and decuplet baryons are studied using SU(3) lattice QCD\nat the quenched level. As an implementation to reduce the statistical\nfluctuation, we employ the anisotropic lattice with $O(a)$ improved quark\naction. In relation to $\\Lambda(1405)$, we measure also the mass of the SU(3)\nflavor-singlet negative-parity baryon, which is described as a three quark\nstate in the quenched lattice QCD, and its lowest mass is measured about 1.6\nGeV. Since the experimentally observed negative-parity baryon $\\Lambda(1405)$\nis much lighter than 1.6 GeV, $\\Lambda(1405)$ may include a large component of\na $N \\bar K$ bound state rather than the three quark state. The mass splitting\nbetween the octet and the decuplet baryons are also discussed in terms of the\ncurrent quark mass.",
        "positive": "Massless Decoupled Doublers: Chiral Yukawa Models and Chiral Gauge\n  Theories: We present a new method for regularizing chiral theories on the lattice. The\narbitrariness in the regularization is used in order to decouple massless\nreplica fermions. A continuum limit with only one fermion is obtained in\nperturbation theory and a Golterman-Petcher like symmetry related to the\ndecoupling of the replicas in the non-perturbative regime is identified. In the\ncase of Chiral Gauge Theories gauge invariance is broken at the level of the\nregularization, so our approach shares many of the characteristics of the Rome\napproach."
    },
    {
        "anchor": "Relations among Supersymmetric Lattice Gauge Theories via Orbifolding: We show how to derive Catterall's supersymmetric lattice gauge theories\ndirectly from the general principle of orbifolding followed by a variant of the\nusual deconstruction. These theories are forced to be complexified due to a\nclash between charge assignments under U(1)-symmetries and lattice assignments\nin terms of scalar, vector and tensor components for the fermions. Other\nprescriptions for how to discretize the theory follow automatically by\norbifolding and deconstruction. We find that Catterall's complexified model for\nthe two-dimensional N=(2,2) theory has two independent preserved\nsupersymmetries. We comment on consistent truncations to lattice theories\nwithout this complexification and with the correct continuum limit. The\nconstruction of lattice theories this way is general, and can be used to derive\nnew supersymmetric lattice theories through the orbifolding procedure. As an\nexample, we apply the prescription to topologically twisted four-dimensional\nN=2 supersymmetric Yang-Mills theory. We show that a consistent truncation is\nclosely related to the lattice formulation previously given by Sugino.",
        "positive": "Conformal finite size scaling of twelve fermion flavors: Extended simulation results and their analysis are reported in a strongly\ncoupled gauge theory with twelve fermion flavors in the fundamental SU(3) color\nrepresentation. The conformality of the model is probed using mass deformed\nconformal finite size scaling (FSS) theory driven by the fermion mass anomalous\ndimension. Two independent conformal FSS fitting procedures are used in the\nanalysis. The first one deploys physics motivated scaling functions,\ncomplemented by a second fitting procedure with spline based general B-forms\nfor the scaling functions. The results at fixed gauge coupling show unresolved\nproblems with the conformal hypothesis."
    },
    {
        "anchor": "Some new results on an old controversy: is perturbation theory the\n  correct asymptotic expansion in nonabelian models?: Several years ago it was found that perturbation theory for two-dimensional\nO(N) models depends on boundary conditions even after the infinite volume limit\nhas been taken termwise, provided $N>2$. There ensued a discussion whether the\nboundary conditions introduced to show this phenomenon were somehow anomalous\nand there was a class of `reasonable' boundary conditions not suffering from\nthis ambiguity. Here we present the results of some computations that may be\ninterpreted as giving some support for the correctness of perturbation theory\nwith conventional boundary conditions; however the fundamental underlying\nquestion of the correctness of perturbation theory in these models and in\nparticular the perturbative $\\beta$ function remain challenging problems of\nmathematical physics.",
        "positive": "A Parallel Cluster Labeling Method for Monte Carlo Dynamics: We present an algorithm for cluster dynamics to efficiently simulate large\nsystems on MIMD parallel computers with large numbers of processors. The method\ndivides physical space into rectangular cells which are assigned to processors\nand combines a serial local procedure with a nearest neighbor relaxation\nprocess. By controlling overhead and reducing inter-processor communication\nthis method attains good performance and speed-up. The complexity and scaling\nproperties of the algorithm are analyzed.\n  The algorithm has been used to simulate large 2d Ising systems (up to 27808 X\n27808 sites) with Swendsen-Wang dynamics. Typical updating times on the order\nof 82 nanosecs/site and efficiencies larger than 90% have been obtained using\n256 processors on the CM-5 supercomputer."
    },
    {
        "anchor": "Numerical Tests of the Improved Fermilab Action: Recently, the Fermilab heavy-quark action was extended to include\ndimension-six and -seven operators in order to reduce the discretization\nerrors. In this talk, we present results of the first numerical simulations\nwith this action (the OK action), where we study the masses of the quarkonium\nand heavy-light systems. We calculate combinations of masses designed to test\nimprovement and compare results obtained with the OK action to their\ncounterparts obtained with the clover action. Our preliminary results show a\nclear improvement.",
        "positive": "The Deconfinement Transition in SU(4) Lattice Gauge Theory: The deconfinement transition in SU(4) lattice gauge theory is studied on\nN_s^3 X N_t lattices with N_s = 8-16 and N_t = 4-8 using a modified Wilson\naction which is expected to have no bulk transitions. The peak of\nsusceptibility \\chi_{|L|} is found to increase linearly with spatial volume for\nN_t = 4, 5, and 6, indicating a first order deconfinement phase transition. The\nlatent heat is estimated to be approximately 2/3 of the corresponding ideal gas\nenergy density at T_c."
    },
    {
        "anchor": "Analysis of systematic errors in the calculation of renormalization\n  constants of the topological susceptibility on the lattice: A Ginsparg-Wilson based calibration of the topological charge is used to\ncalculate the renormalization constants which appear in the field-theoretical\ndetermination of the topological susceptibility on the lattice. A systematic\ncomparison is made with calculations based on cooling. The two methods agree\nwithin present statistical errors (3%-4%). We also discuss the independence of\nthe multiplicative renormalization constant Z from the background topological\ncharge used to determine it.",
        "positive": "Prospects of Solving Grand Challenge Problems: The recent woes of the supercomputer industry and changes in federal funding\nhave caused some scientists to re-evaluate the means by which they hope to\nsolve Grand Challenge problems. I evaluate the potential of Massively Parallel\nProcessors (MPP) within this context and the state of today's MPP. I stress\nthat for solving large-scale problems MPP are crucial and that it is essential\nto seek a balance between CPU performance, memory access time, inter-node\ncommunications, and I/O. To achieve this it is important to preserve certain\ncharacteristics of the hardware while selecting the hottest processor to design\nthe machine around. I emphasize that for long term stability and growth of\nparallel computing priority should be given to standardizing software so that\nthe same code can run on different platforms and on machines ranging from\nclusters of workstations to MPP."
    },
    {
        "anchor": "2+1 Flavor QCD simulated in the epsilon-regime in different topological\n  sectors: We generated configurations with the parametrized fixed-point Dirac operator\nD_{FP} on a (1.6 fm)^4 box at a lattice spacing a=0.13 fm. We compare the\ndistributions of the three lowest k=1,2,3 eigenvalues in the nu= 0,1,2\ntopological sectors with that of the Random Matrix Theory predictions. The\nratios of expectation values of the lowest eigenvalues and the cumulative\neigenvalue distributions are studied for all combinations of k and nu. After\nincluding the finite size correction from one-loop chiral perturbation theory\nwe obtained for the chiral condensate in the MSbar scheme\nSigma(2GeV)^{1/3}=0.239(11) GeV, where the error is statistical only.",
        "positive": "Systematic errors in partially-quenched QCD plus QED lattice simulations: At the precision reached in current lattice QCD calculations, electromagnetic\neffects are becoming numerically relevant. Here, electromagnetic effects are\nincluded by superimposing $\\mathrm{U}(1)$ degrees of freedom on $N_f = 2+1$ QCD\nconfigurations from the Budapest-Marseille-Wuppertal Collaboration. We present\npreliminary results for the electromagnetic corrections to light pseudoscalars\nmesons masses and discuss some of the associated systematic errors."
    },
    {
        "anchor": "Applications of Partially Quenched Chiral Perturbation Theory: Partially quenched theories are theories in which the valence- and sea-quark\nmasses are different. Here, we will discuss the nonanalytic one-loop\ncorrections to some physical quantities, using partially quenched chiral\nperturbation theory. In particular, we will focus on the results for Goldstone\nboson masses to illustrate the general features of our calculation.",
        "positive": "Determination of latent heat at the finite temperature phase transition\n  of SU(3) gauge theory: We calculate the energy gap (latent heat) and pressure gap between the hot\nand cold phases of the SU(3) gauge theory at the first order deconfining phase\ntransition point. We perform simulations around the phase transition point with\nthe lattice size in the temporal direction $N_t=6,$ 8 and 12 and extrapolate\nthe results to the continuum limit. The energy density and pressure are\nevaluated by the derivative method with nonperturabative anisotropy\ncoefficients. We find that the pressure gap vanishes at all values of $N_t$.\nThe spatial volume dependence in the latent heat is found to be small on large\nlattices. Performing extrapolation to the continuum limit, we obtain $\\Delta\n\\epsilon/T^4 = 0.75 \\pm 0.17$ and $\\Delta (\\epsilon -3 p)/T^4 = 0.623 \\pm\n0.056.$ We also tested a method using the Yang-Mills gradient flow. The\npreliminary results are consistent with those by the derivative method within\nthe error."
    },
    {
        "anchor": "On calculating disconnected-type hadronic light-by-light scattering\n  diagrams from lattice QCD: For reliable comparison of the standard model prediction to the muon g-2 with\nits experimental value, the hadronic light-by-light scattering (HLbL)\ncontribution must be calculated by lattice QCD simulation. HLbL contribution\nhas many types of disconnected-type diagrams. Here, we start with recalling the\npoint that must be taken care of in every method to calculate them by lattice\nQCD, and present one concrete method called nonperturbative QED method.",
        "positive": "B-physics from Lattice Gauge Theory: We discuss the main issues in dealing with heavy quarks on the lattice and\nshortly present the different approaches used. We discuss a selection of\ncomputations covering first the b-quark mass and the B(s) meson decay constants\nas the consolidated results (neglecting isospin breaking corrections). In the\nsecond part we consider recent calculations of form factors for tree-level\nsemileptonic decays with emphasis on the tensions between the results produced\nby different collaborations. We propose benchmark quantities and tests suited\nto investigate the origin of such tensions. Finally, we review computations of\nthe bag parameters parameterising neutral meson mixing and provide an overview\non a few recent developments in the field."
    },
    {
        "anchor": "The SU(2) $\\times$ SU(2) chiral spin model in terms of SO(3) and Z$_2$\n  variables: vortices and disorder: We rewrite the two-dimensional SU(2)$\\times$ SU(2) chiral spin model in terms\nof SO(3) and {\\bf Z}$_2$ degrees of freedom. The transformation, which is\nmotivated by a similar representation of the corresponding lattice gauge theory\nin higher dimensions, exhibits the presence of dynamical SO(3) vortices and\nassociated strings. We present arguments that (pairs of) SO(3) vortices with\nlong strings play a crucial role in disordering the spin system at arbitrarily\nlow temperatures.",
        "positive": "Fermion propagators in QED3 with velocity anisotropies: QED3 with fermi and gap anisotropies is considered to be a candidate\neffective field theory of high temperature superconductors. Simulations of a\nvariant of the theory have demonstrated that there is evidence consistent with\na phase transition to a chirally restored phase as the velocity anisotropy\nincreases, and that the correlation lengths of pions in spatial directions\nbehave in a manner consistent with the anisotropy being a relevant parameter of\nthe theory. We present the first measurements of the fermion propagator in\nLandau gauge for this theory and suggest that the structure of this theory is\nmore complex than previously thought."
    },
    {
        "anchor": "The kaon semileptonic form factor in Nf=2+1 domain wall lattice QCD with\n  physical light quark masses: We present the first calculation of the kaon semileptonic form factor with\nsea and valence quark masses tuned to their physical values in the continuum\nlimit of 2+1 flavour domain wall lattice QCD. We analyse a comprehensive set of\nsimulations at the phenomenologically convenient point of zero momentum\ntransfer in large physical volumes and for two different values of the lattice\nspacing. Our prediction for the form factor is f+(0)=0.9685(34)(14) where the\nfirst error is statistical and the second error systematic. This result can be\ncombined with experimental measurements of K->pi decays for a determination of\nthe CKM-matrix element for which we predict |Vus|=0.2233(5)(9) where the first\nerror is from experiment and the second error from the lattice computation.",
        "positive": "Fluctuations and correlations in high temperature QCD: We calculate second- and fourth-order cumulants of conserved charges in a\ntemperature range stretching from the QCD transition region towards the realm\nof (resummed) perturbation theory. We perform lattice simulations with\nstaggered quarks; the continuum extrapolation is based on $N_t=10\\dots24$ in\nthe crossover-region and $N_t=8\\dots16$ at higher temperatures. We find that\nthe Hadron Resonance Gas model predictions describe the lattice data rather\nwell in the confined phase. At high temperatures (above $\\sim$250 MeV) we find\nagreement with the three-loop Hard Thermal Loop results."
    },
    {
        "anchor": "Charm annihilation effects on the hyperfine splitting in charmonium: In calculations of the hyperfine splitting in charmonium, the contributions\nof the disconnected diagrams are considered small and are typically ignored. We\naim to estimate nonperturbatively the size of the resulting correction, which\nmay eventually be needed in high precision calculations of the charmonium\nspectrum. We study this problem in the quenched and unquenched QCD cases. On\ndynamical ensembles the disconnected charmonium propagators contain light modes\nwhich complicate the extraction of the signal at large distances. In the fully\nquenched case, where there are no such light modes, the interpretation of the\nsignal is simplified. We present results from lattices with $a\\approx 0.09$ fm\nand $a\\approx 0.06$ fm.",
        "positive": "Nucleon charges and form factors using clover and HISQ ensembles: We present high statistics ($\\mathcal{O}(2\\times 10^5)$ measurements)\npreliminary results on (i) the isovector charges, $g^{u-d}_{A,S,T}$, and form\nfactors, $G^{u-d}_E(Q^2)$, $G^{u-d}_M(Q^2)$, $G^{u-d}_A(Q^2)$, $\\widetilde\nG^{u-d}_P(Q^2)$, $G^{u-d}_P(Q^2)$, on six 2+1-flavor Wilson-clover ensembles\ngenerated by the JLab/W&M/LANL/MIT collaboration with lattice parameters given\nin Table 1. Examples of the impact of using different estimates of the excited\nstate spectra are given for the clover-on-clover data, and as discussed in [1],\nthe biggest difference on including the lower energy (close to $N\\pi$ and\n$N\\pi\\pi$) states is in the axial channel. (ii) Flavor diagonal axial, tensor\nand scalar charges, $g^{u,d,s}_{A,S,T}$, are calculated with the clover-on-HISQ\nformulation using nine 2+1+1-flavor HISQ ensembles generated by the MILC\ncollaboration [2] with lattice parameters given in Table 2. Once finished, the\ncalculations of $g^{u,d,s}_{A,T}$ will update the results given in Refs.[3,4].\nThe estimates for $g^{u,d,s}_{S}$ and $\\sigma_{N\\pi}$ are new. Overall, a large\npart of the focus is on understanding the excited state contamination (ESC),\nand the results discussed provide a partial status report on developing\ndefensible analyses strategies that include contributions of possible low-lying\nexcited states to individual nucleon matrix elements."
    },
    {
        "anchor": "Testing a generalized cooling procedure in the complex Langevin\n  simulation of chiral Random Matrix Theory: The complex Langevin method has been attracting much attention as a solution\nto the sign problem since the method was shown to work in finite density QCD in\nthe deconfined phase by using the so-called gauge cooling procedure. Whether it\nworks also in the confined phase with light quarks is still an open question,\nthough. In order to shed light on this question, we apply the method to the\nchiral Random Matrix Theory, which describes the epsilon regime of finite\ndensity QCD. Earlier works reported that a naive implementation of the method\nfails to reproduce the known exact results and that the problem can be solved\nby choosing a suitable coordinate. In this work we stick to the naive\nimplementation, and show that a generalized gauge cooling procedure can be used\nto avoid the problem.",
        "positive": "Utilising optimised operators and distillation to extract scattering\n  phase shifts: In this investigation, we examine how the precision of energy spectra and\nscattering phase shifts, extracted in lattice QCD, depend upon the degree of\ndistillation type smearing. We use the variational method to extract energy\nspectra for the isospin-1, $J^{PC}=1^{--}$ channel and use the L\\\"{u}scher\nmethod to compute scattering amplitudes, relevant for the $\\rho$ resonance, in\n$\\pi\\pi$ elastic scattering. Optimised interpolating operators for a single\nground state pion are constructed and these are used to construct two pion\noperators. Calculations are performed on an anisotropic lattice with a pion\nmass of $m_\\pi=236$ MeV. We provide a comprehensive comparison of energy\nspectra and scattering phase shifts across distillation spaces of varying rank."
    },
    {
        "anchor": "Lattice Monte Carlo Data versus Perturbation Theory: Differences between lattice Monte Carlo data and perturbation theory (for\nexample the lack of asymptotic scaling) are usually associated with the `bad'\nbehaviour of the bare lattice coupling g_0 due to the effects of large (and\nunknown) higher order terms in g_0. In this philosophy a new, renormalised\ncoupling g' is defined with the aim of making the higher order coefficients of\nthe perturbative series in g' as small as possible.\n  In this paper an alternative scenario is discussed where lattice artifacts\nare proposed as the cause of the disagreement between Monte Carlo data and the\ng_0-perturbative series. We find that with the addition of a lattice artifact\nterm, the usual asymptotic scaling expression in g_0 is in excellent agreement\nwith Monte Carlo data. Lattice data studied includes the string tension, the\nhadronic scale r_0, the discrete beta function, M_rho, f_pi and the 1P-1S\nsplitting in charmonium.",
        "positive": "Running quark mass in two flavor QCD: We present first results for the step scaling function sigma_P of the\nrenormalization factor Z_P of the pseudoscalar density. The simulations are\nperformed within the framework of the Schroedinger functional with two flavors\nof O(a) improved Wilson fermions. The knowledge of sigma_P is required to\ncompute the renormalization group invariant quark masses. We also study the\nperformance of a variant of the HMC algorithm using two pseudofermion fields."
    },
    {
        "anchor": "Generalization capabilities of neural networks in lattice applications: In recent years, the use of machine learning has become increasingly popular\nin the context of lattice field theories. An essential element of such theories\nis represented by symmetries, whose inclusion in the neural network properties\ncan lead to high reward in terms of performance and generalizability. A\nfundamental symmetry that usually characterizes physical systems on a lattice\nwith periodic boundary conditions is equivariance under spacetime translations.\nHere we investigate the advantages of adopting translationally equivariant\nneural networks in favor of non-equivariant ones. The system we consider is a\ncomplex scalar field with quartic interaction on a two-dimensional lattice in\nthe flux representation, on which the networks carry out various regression and\nclassification tasks. Promising equivariant and non-equivariant architectures\nare identified with a systematic search. We demonstrate that in most of these\ntasks our best equivariant architectures can perform and generalize\nsignificantly better than their non-equivariant counterparts, which applies not\nonly to physical parameters beyond those represented in the training set, but\nalso to different lattice sizes.",
        "positive": "Maximal twist and the spectrum of quenched twisted mass lattice QCD: Results on the hadron masses for a degenerate doublet of up and down quarks\nfrom quenched twisted mass lattice QCD at maximal twist are presented. Two\ndefinitions of maximal twist are used and the hadron masses for these\ndefinitions are compared. Mass splittings within the Delta(1232) multiplet due\nto flavor breaking effects are discussed."
    },
    {
        "anchor": "On the nature of the residual meson-meson interaction from simulations\n  with a QED${}_{2+1}$ model: A potential between mesons is extracted from 4-point functions within lattice\ngauge theory taking 2+1 dimensional QED as an example. This theory possesses\nconfinement and dynamical fermions. The resulting meson-meson potential has a\nshort-ranged hard repulsive core and the expected dipole-dipole forces lead to\nattraction at intermediate distances. Sea quarks lead to a softer form of the\ntotal potential.",
        "positive": "Three-Quark Potential in SU(3) Lattice QCD: The static three-quark (3Q) potential is measured in the SU(3) lattice QCD\nwith $12^3 \\times 24$ and $\\beta=5.7$ at the quenched level. From the 3Q Wilson\nloop, the 3Q ground-state potential $V_{\\rm 3Q}$ is extracted using the\nsmearing technique for the ground-state enhancement. With accuracy better than\na few %, $V_{\\rm 3Q}$ is well described by a sum of a constant, the two-body\nCoulomb term and the three-body linear confinement term $\\sigma_{\\rm 3Q} L_{\\rm\nmin}$, where $L_{\\rm min}$ denotes the minimal length of the color flux tube\nlinking the three quarks. By comparing with the Q-$\\bar {\\rm Q}$ potential, we\nfind a universal feature of the string tension, $\\sigma_{\\rm 3Q} \\simeq\n\\sigma_{\\rm Q \\bar Q}$, as well as the one-gluon-exchange result for the\nCoulomb coefficient, $A_{\\rm 3Q} \\simeq \\frac12 A_{\\rm Q \\bar Q}$."
    },
    {
        "anchor": "A light composite scalar in eight-flavor QCD on the lattice: In search for a composite Higgs boson (techni-dilaton) in the walking\ntechnicolor, we present our preliminary results on the first observation of a\nlight flavor-singlet scalar in a candidate theory for the walking technicolor,\nthe Nf=8 QCD, which was found in our previous paper to have spontaneous chiral\nsymmetry breaking together with remnants of the conformality. Based on\nsimulations with the HISQ-type action on several lattice sizes with various\nfermion masses, we find evidence of a flavor-singlet scalar meson with mass\ncomparable to that of the Nambu-Goldstone pion in both the small fermion-mass\nregion, where chiral perturbation theory works, and the intermediate\nfermion-mass region where the hyperscaling relation holds. We further discuss\nits chiral limit extrapolation in comparison with other states studied in our\nprevious paper: the scalar has a mass much smaller than that of the vector\nmeson, which is compared to the Nambu-Goldstone pion having a vanishing mass in\nthat limit.",
        "positive": "Finite temperature Lattice QCD with two flavors of improved Wilson\n  fermions: We present results of finite temperature QCD from N_f=2 flavors of\nnon-perturbatively improved Wilson fermions on lattices with N_t=8, 10 and 12.\nThe transition temperature T_c is determined for the first time at lattice\nspacings as low as a = 0.08 fm, albeit at pion masses 1.3 < r_0 m_\\pi. We\nfurthermore compute the screening masses in various color channels at T>T_c."
    },
    {
        "anchor": "The Abelianicity of Cooled SU(2) Lattice Configurations: We introduce a gauge-invariant measure of the local \"abelianicity\" of any\ngiven lattice configuration in non-abelian lattice gauge theory; it is\nessentially a comparison of the magnitude of field strength commutators to the\nmagnitude of the field strength itself. This measure, in conjunction with the\ncooling technique, is used to probe the SU(2) lattice vacuum for a possible\nlarge-scale abelian background, underlying the local short-range field\nfluctuations. We do, in fact, find a substantial rise in abelianicity over 10\ncooling steps or so, after which the abelianicity tends to drop again.",
        "positive": "Evidence for the Role of Instantons in Hadron Structure from Lattice QCD: Cooling is used as a filter on a set of gluon fields sampling the Wilson\naction to selectively remove essentially all fluctuations of the gluon field\nexcept for the instantons. The close agreement between quenched lattice QCD\nresults with cooled and uncooled configurations for vacuum correlation\nfunctions of hadronic currents and for density-density correlation functions in\nhadronic bound states provides strong evidence for the dominant role of\ninstantons in determining light hadron structure and quark propagation in the\nQCD vacuum."
    },
    {
        "anchor": "Solution to new sign problems with Hamiltonian Lattice Fermions: We present a solution to the sign problem in a class of particle-hole\nsymmetric Hamiltonian lattice fermion models on bipartite lattices using the\nidea of fermion bags. The solution remains valid when the particle-hole\nsymmetry is broken through a staggered chemical potential term. This solution\nallows, for the first time, simulations of some massless four-fermion models\nwith minimal fermion doubling and with an odd number of fermion flavors using\nultra-local actions. One can thus study a variety of quantum phase transitions\nthat have remained unexplored so far due to sign problems.",
        "positive": "String tension from smearing and Wilson flow methods: Recently, we proposed a new method to extract the string tension from\n4-dimensionally smeared Wilson loops. In this talk, we first show that the\nresults obtained using this smearing method are identical to those obtained by\nWilson flow, once the time step is sufficiently small. We then demonstrate the\npractical advantage of our method by applying it to the calculation of string\ntension in SU(3) Yang-Mills theory."
    },
    {
        "anchor": "Simulation of dynamical (u,d,s,c) domain-wall/overlap quarks at the\n  physical point: We perform hybrid Monte-Carlo simulation of $N_f=2+1+1 $ lattice QCD with\ndomain-wall quarks at the physical point. The simulation is carried out on the\n$ L^3 \\times T = 64^3 \\times 64 $ lattice with lattice spacing $a \\sim 0.064 $\nfm ($ L > 4 $ fm, and $ M_\\pi L > 3 $), using the Nvidia DGX-1 (8 V100 GPUs\ninterconnected by the NVLink). To attain the maximal chiral symmetry for a\nfinite extent ($N_s=16$) in the fifth dimension, we use the optimal domain-wall\nfermion for the quark action, together with the exact one-flavor action for\ndomain-wall fermion. We outline the salient features of our simulation (without\ntopology freezing, and small residual mass), together with the preliminary\nresult of the masses of $ \\pi^\\pm $, $ K^\\pm $, and $ D^\\pm $.",
        "positive": "Chiral symmetry breaking and the generation of light hadron masses: A quantitative study of the effects of dynamical chiral symmetry breaking on\nthe mass generation of the low-lying hadrons in a dynamical lattice QCD\nsimulation is presented. The evolution of light hadron masses upon increasing\nthe number of low-lying Dirac operator eigenmodes in the quark propagators is\nconfronted with the hadron masses obtained upon removal of such low-lying\neigenmodes from standard full quark propagators. The low-lying chiral symmetry\nbreaking modes provide roughly two third of the nucleon and $\\rho$ masses,\nwhile the $a_1$ mass is affected to a much smaller degree."
    },
    {
        "anchor": "Complex Paths Around The Sign Problem: The Monte Carlo evaluation of path integrals is one of a few general purpose\nmethods to approach strongly coupled systems. It is used in all branches of\nPhysics, from QCD/nuclear physics to the correlated electron systems. However,\nmany systems of great importance (dense matter inside neutron stars, the\nrepulsive Hubbard model away from half-filling, dynamical and non-equilibrium\nobservables) are not amenable to the Monte Carlo method as it currently stands\ndue to the so-called \"sign-problem\". We review a new set of ideas recently\ndeveloped to tackle the sign problem based on the complexification of field\nspace and the Picard-Lefshetz theory accompanying it. The mathematical ideas\nunderpinning this approach, as well as the algorithms so far developed, are\ndescribed together with non-trivial examples where the method has already been\nproved successful. Directions of future work, including the burgeoning use of\nmachine learning techniques, are delineated.",
        "positive": "Continuum interpretation of the dynamical-triangulation formulation of\n  quantum Einstein gravity: In the time-space symmetric version of dynamical triangulation, a\nnon-perturbative version of quantum Einstein gravity, numerical simulations\nwithout matter have shown two phases, with spacetimes that are either crumpled\nor elongated like branched polymers, with strong evidence of a first-order\ntransition between them. These properties have generally been considered\nunphysical. Using previously unpublished numerical results, we give an\ninterpretation in terms of continuum spacetimes that have constant positive and\nnegative curvature, respectively in the 'elongated' and 'crumpled' phase. The\nmagnitude of the positive curvature leads naturally to average spacetimes\nconsisting solely of baby-universes in a branched-polymer structure, whereas\nthe negative curvature accommodates easily a large mother universe, albeit with\na crumpling singularity. Nevertheless, there is evidence for scaling in the\ncrumpled phase, which we compare with the well-known scaling in the elongated\nphase. Using constraint effective-action models we analyze existing numerical\nsusceptibility-data of the phase transition and determine the behavior of the\naverage Regge-curvature. We propose a renormalization of the Regge curvature\nand compare it to the curvature of the above continuum spacetimes, and also to\nthe curvature implied by the Gauss-Bonnet theorem in the continuum. The latter\ninvolves a more benign multiplicative renormalization and suggests that\nsimulations at larger volumes are needed to settle the order of the phase\ntransition."
    },
    {
        "anchor": "Implementation of C* boundary conditions in the Hybrid Monte Carlo\n  algorithm: In the study of QCD dynamics, C* boundary conditions are physically relevant\nin certain cases. In this paper we study the implementation of these boundary\nconditions in the lattice formulation of full QCD with staggered fermions. In\nparticular, we show that the usual even-odd partition trick to avoid the\nredoubling of the fermion matrix is still valid in this case. We give an\nexplicit implementation of these boundary conditions for the Hybrid Monte Carlo\nalgorithm.",
        "positive": "Exact chiral symmetry, topological charge and related topics: It has been shown recently that Dirac operators satisfying the\nGinsparg-Wilson relation provide a solution of the chirality problem in QCD at\nfinite lattice spacing. We discuss different ways to construct these operators\nand their properties. The possibility to define lattice chiral gauge theories\nis briefly discussed as well."
    },
    {
        "anchor": "Pade-Borel approximation of the continuum limit of strong coupling\n  lattice fields: Two dimensional non-linear O(N) sigma model at N>=3: Based on the strong coupling expansion, we reinvestigate two dimensional O(N)\nsigma model by the use of Pade-Borel approximants. The conventional strong\ncoupling expansion of the mass square M in momentum space in beta=1/g^2 is\ninverted to give beta expanded in 1/M. Borel transform of beta with respect to\nM is carried out and the result is improved as the rational function by Pade\nmethod. We find the behavior of Pade-Borel transformed bare coupling at 18th\norder is consistent for N>=3 with that of continuum scaling to the four-loop\nperturbation theory. We estimate non-perturbative mass gap at N>=3 and find the\nagreement with the exact result by Hasenfratz et.al.",
        "positive": "Optimizing the domain wall fermion Dirac operator using the R-Stream\n  source-to-source compiler: The application of the Dirac operator on a spinor field, the Dslash\noperation, is the most computation-intensive part of the lattice QCD\nsimulations. It is often the key kernel to optimize to achieve maximum\nperformance on various platforms. Here we report on a project to optimize the\ndomain wall fermion Dirac operator in Columbia Physics System (CPS) using the\nR-Stream source-to-source compiler. Our initial target platform is the Intel PC\nclusters. We discuss the optimization strategies involved before and after the\nautomatic code generation with R-Stream and present some preliminary benchmark\nresults."
    },
    {
        "anchor": "Proton Spin Structure from Lattice QCD: A lattice QCD calculation of the proton matrix element of the flavor singlet\naxial-vector current is reported. Both the connected and disconnected\ncontributions are calculated, for the latter employing the variant method of\nwall source without gauge fixing. From simulations in quenched QCD with the\nWilson quark action on a $16^3\\times 20$ lattice at $\\beta=5.7$ (the lattice\nspacing $a\\approx 0.14$fm), we find $\\Delta\\Sigma=\\Delta u+\\Delta d+\\Delta\ns=+0.638(54)-0.347(46)-0.109(30) = +0.18(10)$ with the disconnected\ncontribution to $\\Delta u$ and $\\Delta d$ equal to $-0.119(44)$, which is\nreasonably consistent with the experiment.",
        "positive": "Beauty mesons in $N_f=2+1+1+1 $ lattice QCD with exact chiral symmetry: We present the first study of $N_f=2+1+1+1$ lattice QCD with domain-wall\nquarks. The $(b, c, s)$ quarks are physical, while the $(u, d)$ quarks are\nheavier than their physical masses, with the pion mass $ \\sim 700 $ MeV. The\ngauge ensemble is generated by hybrid Monte Carlo simulation with the Wilson\ngauge action for the gluons, and the optimal domain-wall fermion action for the\nquarks. Using point-to-point quark propagators, we measure the time-correlation\nfunctions of quark-antiquark meson interpolators with quark contents $\\bar b\nb$, $\\bar b c$, $\\bar b s$, and $ \\bar c c$, and obtain the masses of the\nlow-lying mesons. They are in good agreement with the experimental values, plus\nsome predictions which have not been observed in experiments. Moreover, we also\ndetermine the masses of $(b, c, s)$ quarks."
    },
    {
        "anchor": "Hypercubic Random Surfaces with Extrinsic Curvature: We analyze a model of hypercubic random surfaces with an extrinsic curvature\nterm in the action. We find a first order phase transition at finite coupling\nseparating a branched polymer from a stable flat phase.",
        "positive": "Heavy-light spectrum and decay constant from NRQCD with two flavors of\n  dynamical quarks: We report on a study of B mesons on N_f = 2 full QCD configurations using an\nRG-improved gauge action, NRQCD heavy quark action and tadpole-improved clover\nlight quark action. Results on the heavy-light spectrum and the decay constants\nfrom 16^3x32 lattices at a^{-1} ~ 1.5 GeV are presented, and compared with\nquenched results obtained with the same action combination at matching lattice\nspacings."
    },
    {
        "anchor": "Computing Nucleon Electric Dipole Moment from lattice QCD: Electric dipole moments (EDMs) of nucleons and nuclei are actively considered\nas direct evidence of the CP violation. Calculations of nucleon EDMs on lattice\nare required to connect the quark- and hadron- level effective CP violating\ninteractions within QCD or other CP violating sources in new physics beyond the\nstandard model. Among them, the theta-induced nucleon EDM, that is the only\nsuch renormalizable interaction, has widely been investigated on a lattice. In\nthe report, we review recent developments of the lattice calculations of\nnucleon EDM induced QCD theta term.",
        "positive": "Confinement-Deconfinement transition and $Z_2$ symmetry in $Z_2+$Higgs\n  theory: We study the Polyakov loop and the $Z_2$ symmetry in the lattice $Z_2+$Higgs\ntheory in 4D Euclidean space using Monte Carlo simulations. The results show\nthat this symmetry is realised in the Higgs symmetric phase for large number of\ntemporal lattice sites. To understand the dependence on the number of temporal\nsites, we consider a one dimensional model by keeping terms of the original\naction corresponding to a single spatial site. In this approximation the\npartition function can be calculated exactly as a function of the Polyakov\nloop. The resulting free energy is found to have the $Z_2$ symmetry in the\nlimit of large temporal sites. We argue that this is due to $Z_2$ invariance as\nwell as dominance of the distribution or density of states corresponding to the\naction."
    },
    {
        "anchor": "Effects of Dense Quark Matter on Gluon Propagators in Lattice QC$_2$D: The transverse and longitudinal gluon propagators in the Landau gauge are\nstudied in the two-color lattice QCD at nonzero quark chemical potential\n$\\mu_q$. Parameterization of the momentum dependence of the propagators is\nprovided for all values of chemical potential under study. We find that the\nlongitudinal propagator is infrared suppressed at nonzero $\\mu_q$ with\nsuppression increasing with increasing $\\mu_q$. The transverse propagator\ndependence on $\\mu_q$ was found to be opposite: it is enhanced at large\n$\\mu_q$. It is found, respectively, that the electric screening mass is\nincreasing while the magnetic screening mass is decreasing with increasing\n$\\mu_q$. Nice agreement between the electric screening mass computed from the\nlongitudinal propagator and the Debye mass computed earlier from the singlet\nstatic quark-antiquark potential was found. We discuss how the dependence of\nthe propagators on the chemical potential correlates with the respective\ndependence of the string tension. Additionally, we consider the difference\nbetween two propagators as a function of the momentum and make interesting\nobservations.",
        "positive": "The spectrum of static-light baryons in twisted mass lattice QCD: We compute the static-light baryon spectrum with N_f = 2 flavors of sea\nquarks using Wilson twisted mass lattice QCD. As light valence quarks we\nconsider quarks, which have the same mass as the sea quarks with corresponding\npion masses in the range 340 MeV < m_PS < 525 MeV, as well as partially\nquenched quarks, which have the mass of the physical s quark. We extract masses\nof states with isospin I = 0, 1/2, 1, with strangeness S = 0, -1, -2, with\nangular momentum of the light degrees of freedom j = 0, 1 and with parity P =\n+, -. We present a preliminary extrapolation in the light u/d and an\ninterpolation in the heavy b quark mass to the physical point and compare with\navailable experimental results."
    },
    {
        "anchor": "Freezing a Fluid Random Surface: We investigate a dynamically triangulated random surface action that consists\nof a gaussian term plus the modulus of the intrinsic scalar curvature. We find\nthat the flips are frozen out and the internal geometry is regularized as the\ncoefficient of the latter term is increased. Such a term thus provides a way of\ninterpolating between dynamically triangulated (ie fluid) and crystalline\nrandom surfaces.",
        "positive": "Phase diagram of Regge quantum gravity coupled to SU(2) gauge theory: We analyze Regge quantum gravity coupled to SU(2) gauge theory on $4^3\\times\n2$, $6^{3}\\times 4$ and $8^{3}\\times 4$ simplicial lattices. It turns out that\nthe window of the well-defined phase of the gravity sector where geometrical\nexpectation values are stable extends to negative gravitational couplings as\nwell as to gauge couplings across the deconfinement phase transition. We study\nthe string tension from Polyakov loops, compare with the $\\beta$-function of\npure gauge theory and conclude that a physical limit through scaling is\npossible."
    },
    {
        "anchor": "Instantons in the Maximally Abelian Gauge: We investigate the Maximally Abelian (MA) Projection for a single $SU(2)$\ninstanton in continuum gauge theory. We find that there is a class of solutions\nto the differential MA gauge condition with circular monopole loops of radius\n$R$ centered on the instanton of width $\\rho$. However, the MA gauge fixing\nfunctional $G$ decreases monotonically as $R/\\rho \\rightarrow 0$. Its global\nminimum is the instanton in the singular gauge. We point out that interactions\nwith nearby anti-instantons are likely to excite these monopole loops.",
        "positive": "Renormalization of the Yukawa and Quartic Couplings in $\\mathcal{N} = 1$\n  Supersymmetric QCD: In this work we perform calculations in order to determine the\nrenormalization factors and the mixing coefficients of the Yukawa and the\nquartic couplings in $\\mathcal{N} = 1$ Supersymmetric QCD. The Yukawa couplings\ndescribe the interactions between gluino, quark and squark fields whereas the\nquartic couplings describe four-squark interactions. We discretize the action\non a Euclidean lattice using the Wilson formulation for the gluino, quark and\ngluon fields; for squark fields (scalar fields) we employ na\\\"ive\ndiscretization. At the quantum level Yukawa and quartic interactions suffer\nfrom mixing with other operators which have the same transformation properties.\nExploiting parity and charge conjugation symmetries of the Supersymmetric QCD\naction, we reduce the allowed mixing patterns. We compute, perturbatively to\none-loop and to the lowest order in the lattice spacing, the relevant\nthree-point Green's functions so as to fine tune the Yukawa couplings and the\nrelevant four-point Green's functions to fine tune the quartic couplings. We\nuse both dimensional and lattice regularizations as required for implementing\nthe Modified Minimal Subtraction scheme ($\\overline{\\rm MS}$)."
    },
    {
        "anchor": "Low-lying spectrum for lattice Dirac operators with twisted mass: We analyze the low-lying spectrum and eigenmodes of lattice Dirac operators\nwith a twisted mass term. The twist term expels the eigenvalues from a strip in\nthe complex plane and all eigenmodes obtain a non-vanishing matrix element with\ngamma-5. For a twisted Ginsparg-Wilson operator the spectrum is located on two\narcs in the complex plane. Modes due to non-trivial topological charge of the\nunderlying gauge field have their eigenvalues at the edges of these arcs and\nobey a remnant index theorem. For configurations in the confined phase we find\nthat the twist mainly affects the zero modes, while the bulk of the spectrum is\nessentially unchanged.",
        "positive": "Computation of the strong coupling in QCD with two dynamical flavours: We present a non-perturbative computation of the running of the coupling\nalpha_s in QCD with two flavours of dynamical fermions in the Schroedinger\nfunctional scheme. We improve our previous results by a reliable continuum\nextrapolation. The Lambda-parameter characterizing the high-energy running is\nrelated to the value of the coupling at low energy in the continuum limit. An\nestimate of Lambda*r_0 is given using large-volume data with lattice spacings a\nfrom 0.07 fm to 0.1 fm. It translates into Lambda_{MSbar}^{(2)}=245(16)(16) MeV\n[assuming r_0=0.5 fm]. The last step still has to be improved to reduce the\nuncertainty."
    },
    {
        "anchor": "Study of QCD critical point using the canonical ensemble method: The existence of the QCD critical point at non-zero baryon density is not\nonly of great interest for experimental physics but also a challenge for the\ntheory. Any hint of the existence of the first order phase transition and,\nparticularly, its critical point will be valuable towards a full understanding\nof the QCD phase diagram. We use lattice simulation based on the canonical\nensemble method to explore the finite baryon density and finite temperature\nregion and look for the QCD critical point. As a benchmark, we run simulations\nfor the four degenerate flavor QCD where we observe a clear signal of the\nexpected first order phase transition. In the two flavor case, we do not see\nany signal for temperatures as low as $0.83 \\rm{T_c}$. Although our real world\ncontains two light quarks and one heavier quark, three degenerate flavor case\nshares a lot of similar phase structures as the QCD. We scan the phase diagram\nusing clover fermions with $m_\\pi \\approx 700{MeV}$ on $6^3\\times4$ lattices.\nThe baryon chemical potential is measured as we increase the baryon number and\nwe see the characteristic \"S-shape\" that signals the first order phase\ntransition. We determine the phase boundaries by Maxwell construction and\nreport our preliminary results for the location of critical point for the\npresent lattice.",
        "positive": "Some results on excited hadrons in 2-flavor QCD: Results of hadron spectroscopy with two dynamical mass-degenerate chirally\nimproved quarks are presented. Three ensembles with pion masses of 322(5),\n470(4) and 525(7) MeV, lattices of size 16^3 \\times 32, and lattice spacings\nclose to 0.15 fm are investigated. We discuss the possible appearance of\nscattering states, considering masses and eigenvectors. Partially quenched\nresults in the scalar channel suggest the presence of a 2-particle state,\nhowever, in most channels we cannot identify them. Where available, we compare\nto results from quenched simulations using the same action."
    },
    {
        "anchor": "Improvement of the Staggered Fermion Operators: We present a complete and detailed derivation of the finite lattice spacing\ncorrections to staggered fermion matrix elements. Expanding upon arguments of\nSharpe, we explicitly implement the Symanzik improvement program demonstrating\nthe absence of order $a$ terms in the Symanzik improved action. We propose a\ngeneral program to improve fermion operators to remove $O(a)$ corrections from\ntheir matrix elements, and demonstrate this program for the examples of matrix\nelements of fermion bilinears and $B_K$. We find the former does have $O(a)$\ncorrections while the latter does not.",
        "positive": "Model-independent determination of the nucleon charge radius from\n  lattice QCD: Lattice QCD calculations of nucleon form factors are restricted to discrete\nvalues of the Euclidean four-momentum transfer. Therefore, the extraction of\nradii typically relies on parametrizing and fitting the lattice QCD data to\nobtain its slope close to zero momentum transfer. We investigate a new method,\nwhich allows to compute the nucleon radius directly from existing lattice QCD\ndata, without assuming a functional form for the momentum dependence of the\nunderlying form factor. The method is illustrated for the case of the isovector\nmean square charge radius of the nucleon $\\langle r^2_\\mathrm{isov} \\rangle$\nand the quark-connected contributions to $\\langle r^2_p\\rangle$ and $\\langle\nr^2_n \\rangle$ for the proton and neutron, respectively. Computations are\nperformed using a single gauge ensemble with $N_f=2+1+1$ maximally twisted mass\nclover-improved fermions at physical quark mass and a lattice spacing of\n$a=0.08\\mathrm{fm}$."
    },
    {
        "anchor": "A Study of the $N=2$ Kazakov-Migdal Model: We study numerically the SU(2) Kazakov-Migdal model of `induced QCD'. In\ncontrast to our earlier work on the subject we have chosen here {\\it not} to\nintegrate out the gauge fields but to keep them in the Monte Carlo simulation.\nThis allows us to measure observables associated with the gauge fields and\nthereby address the problem of the local $Z_2$ symmetry present in the model.\nWe confirm our previous result that the model has a line of first order phase\ntransitions terminating in a critical point. The adjoint plaquette has a clear\ndiscontinuity across the phase transition, whereas the plaquette in the\nfundamental representation is always zero in accordance with Elitzur's theorem.\nThe density of small $Z_2$ monopoles shows very little variation and is always\nlarge. We also find that the model has extra local U(1) symmetries which do not\nexist in the case of the standard adjoint theory. As a result, we are able to\nshow that two of the angles parameterizing the gauge field completely decouple\nfrom the theory and the continuum limit defined around the critical point can\ntherefore not be `QCD'.",
        "positive": "Embedding Z(3) in SU(3): We consider the design of a non-local MonteCarlo algorithm for $SU(3)$\nlattice systems according to the idea of {\\em embedding} the degrees of freedom\ncorresponding to the center of the group $Z(3)$. As a crucial ingredient to\nreach this goal, we present a practical implementation of a cluster algorithm\nfor $Z(3)$ systems with general random pair interaction."
    },
    {
        "anchor": "Properties of Interfaces in the two and three dimensional Ising Model: To investigate order-order interfaces, we perform multimagnetical Monte Carlo\nsimulations of the $2D$ and $3D$ Ising model. Following Binder we extract the\ninterfacial free energy from the infinite volume limit of the magnetic\nprobability density. Stringent tests of the numerical methods are performed by\nreproducing with high precision exact $2D$ results. In the physically more\ninteresting $3D$ case we estimate the amplitude $F^s_0$ of the critical\ninterfacial tension $F^s = F^s_0 t^\\mu$ to be $F^s_0 = 1.52 \\pm 0.05$. This\nresult is in good agreement with a previous MC calculation by Mon, as well as\nwith experimental results for related amplitude ratios. In addition, we study\nin some details the shape of the magnetic probability density for temperatures\nbelow the Curie point.",
        "positive": "Emergence of a new $SU(4)$ symmetry in the baryon spectrum: Recently a large degeneracy of $J=1$ mesons, that is larger than the $SU(2)_L\n\\times SU(2)_R \\times U(1)_A$ symmetry of the QCD Lagrangian, has been\ndiscovered upon truncation of the near-zero modes from the valence quark\npropagators. It has been found that this degeneracy represents the $SU(4)$\ngroup that includes the chiral rotations as well as the mixing of left- and\nright-handed quarks. This symmetry group turns out to be a symmetry of\nconfinement in QCD. Consequently, one expects that the same symmetry should\npersist upon the near-zero mode removal in other hadron sectors as well. It has\nbeen shown that indeed the $J=2$ mesons follow the same symmetry pattern upon\nthe low-lying mode elimination. Here we demonstrate the $SU(4)$ symmetry of\nbaryons once the near-zero modes are removed from the quark propagators. We\nalso show a degeneracy of states belonging to different irreducible\nrepresentations of $SU(4)$. This implies a larger symmetry, that includes\n$SU(4)$ as a subgroup."
    },
    {
        "anchor": "Many faces of the Landau gauge gluon propagator at zero and finite\n  temperature: positivity violation, spectral density and mass scales: We address several aspects of gluon propagation at zero and finite\ntemperature. In particular, we study the violation of spectral positivity, we\ndiscuss a method to extract the K\\\"all\\'{e}n-Lehmann spectral density of a\nparticle (be it elementary or bound state) propagator and apply it to compute\ngluon spectral densities from lattice data. Furthermore, we also consider the\ninterpretation of the Landau gauge gluon propagator at finite temperature as a\nmassive type bosonic propagator.",
        "positive": "Fighting topological freezing in the two-dimensional CP$^{N-1}$ model: We perform Monte Carlo simulations of the CP$^{N-1}$ model on the square\nlattice for $N=10$, $21$, and $41$. Our focus is on the severe slowing down\nrelated to instantons. To fight this problem we employ open boundary conditions\nas proposed by L\\\"uscher and Schaefer for lattice QCD. Furthermore we test the\nefficiency of parallel tempering of a line defect. Our results for open\nboundary conditions are consistent with the expectation that topological\nfreezing is avoided, while autocorrelation times are still large. The results\nobtained with parallel tempering are encouraging."
    },
    {
        "anchor": "Excitations of the nucleon with dynamical fermions: We measure the spectrum of low-lying nucleon resonances using Bayesian\nfitting methods. We compare the masses obtained in the quenched approximation\nto those obtained with two flavours of dynamical fermions at a matched lattice\nspacing. At the pion masses employed in our simulations, we find that the mass\nof the first positive-parity nucleon excitation is always greater than that of\nthe parity partner of the nucleon.",
        "positive": "Critical region of the random bond Ising model: We describe results of the cluster algorithm Special Purpose Processor\nsimulations of the 2D Ising model with impurity bonds. Use of large lattices,\nwith the number of spins up to $10^6$, permitted to define critical region of\ntemperatures, where both finite size corrections and corrections to scaling are\nsmall. High accuracy data unambiguously show increase of magnetization and\nmagnetic susceptibility effective exponents $\\beta$ and $\\gamma$, caused by\nimpurities. The $M$ and $\\chi$ singularities became more sharp, while the\nspecific heat singularity is smoothed. The specific heat is found to be in a\ngood agreement with Dotsenko-Dotsenko theoretical predictions in the whole\ncritical range of temperatures."
    },
    {
        "anchor": "Strings in SU(N) gauge theories in 2+1 dimensions: beyond the\n  fundamental representation: We calculate energies and tensions of closed k-strings in (2+1)-dimensional\nSU(N) gauge theories with N=4,5,6,8. When we study the dependence of the ground\nstate energy on the string length, we find that it is well described by a\nNambu-Goto (NG) free bosonic string for large lengths. At shorter lengths we\nsee deviations which we fit, and this allows us to control the systematic error\ninvolved in extracting the tension. We compare the resulting string tensions\nwith Casimir scaling, which we find to be lower than our data by 1%-4%.\nExtrapolating our results to N=oo we see that our data fits more naturally to\n1/N rather than 1/N^2 corrections. Finally, we see that the full spectrum of\nthe k-string states falls into sectors that belong to particular irreducible\nrepresentations of SU(N).",
        "positive": "Theories with global gauge anomalies on the lattice: A global anomaly in a chiral gauge theory manifests itself in different ways\nin the continuum and on the lattice. In the continuum case, functional\nintegration of the fermion determinant over the whole space of gauge fields\nyields zero. In the case of the lattice, it is not even possible to define a\nfermion measure over the whole space of gauge configurations. However, this is\nnot necessary, and as in the continuum, a reduced functional integral is\nsufficient for the existence of the theory."
    },
    {
        "anchor": "Phase Structure of Four Dimensional Simplicial Quantum Gravity: We present the results of a high statistics Monte Carlo study of a model for\nfour dimensional euclidean quantum gravity based on summing over\ntriangulations. We show evidence for two phases; in one there is a logarithmic\nscaling on the mean linear extent with volume, whilst the other exhibits power\nlaw behaviour with exponent 1/2. We are able to extract a finite size scaling\nexponent governing the growth of the susceptibility peak",
        "positive": "Diffusion of topological charge in lattice QCD simulations: We study the autocorrelations of observables constructed from the topological\ncharge density, such as the topological charge on a time slice or in a\nsubvolume, using a series of hybrid Monte Carlo simulations of pure SU(3) gauge\ntheory with both periodic and open boundary conditions. We show that the\nautocorrelation functions of these observables obey a simple diffusion equation\nand we measure the diffusion coefficient, finding that it scales like the\nsquare of the lattice spacing. We use this result and measurements of the rate\nof tunneling between topological charge sectors to calculate the scaling\nbehavior of the autocorrelation times of these observables on periodic and open\nlattices. There is a characteristic lattice spacing at which open boundary\nconditions become worthwhile for reducing autocorrelations and we show how this\nlattice spacing is related to the diffusion coefficient, the tunneling rate,\nand the lattice Euclidean time extent."
    },
    {
        "anchor": "Baryon-baryon interaction of strangeness S=-1 sector: We present our recent studies on hyperon-nucleon (YN) interactions in the\nstrangeness S=-1 that $p\\Lambda, \\Sigma^0 p$ and $\\Sigma^+ n$, by extracting\ncorresponding potentials through Nambu-Bethe-Salpeter wave functions. We\ncalculate $\\Lambda N$ and $\\Sigma N$ potentials in the isospin I=3/2 channel,\nusing the $N_f=2+1$ gauge configurations generated by PACS-CS collaboration and\nemploying an improved method to obtain potentials in lattice QCD simulations.\nFor the $^1S_0$ channel, the central $\\Sigma N (I=3/2, ^1S_0)$ potential and\nthe central $\\Lambda N (^1S_0)$ potential are found to be very similar. In the\nspin triplet ($^3S_1-^3D_1$) channels, the central $\\Lambda N(^3S_1-^3D_1)$\npotential is attractive while the central $\\Sigma N(I=3/2, ^3S_1-^3D_1)$\npotentials is repulsive. Tensor potentials, on the other hand, are rather weak\nin the diagonal part of both $\\Lambda N$ and $\\Sigma N(I=3/2)$ systems.",
        "positive": "Muon $g-2$: Lattice calculations of the hadronic vacuum polarization: The experimental uncertainty on the anomalous magnetic moment of the muon has\nbeen significantly reduced with the recent results of the Fermilab $g-2$\nexperiment, and a further reduction is expected in the near future. The\nprecision of the Standard Model prediction needs to improve correspondingly to\nincrease the sensitivity of tests for physics beyond the Standard Model. The\nlargest uncertainty is due to contributions from the strong interaction, in\nparticular the hadronic vacuum polarization (HVP) contribution. Lattice QCD\ncalculations have the potential to provide precise ab initio predictions of the\nHVP contribution. We review the state of lattice QCD calculations, focusing on\nthe dominant sources of uncertainty that need to be controlled to provide\nresults with sub-percent precision."
    },
    {
        "anchor": "Baryon Masses in Partially Quenched Heavy Hadron Chiral Perturbation\n  Theory: The masses of baryons containing a heavy quark are calculated to\nnext-to-leading order in partially quenched heavy hadron chiral perturbation\ntheory. Calculations are performed for three light flavors in the isospin limit\nand additionally for two light non-degenerate flavors. The results presented\nare necessary for extrapolating lattice QCD and partially quenched lattice QCD\ncalculations of the heavy hadron masses.",
        "positive": "Update on lattice QCD with domain wall quarks: Using domain wall fermions, we estimate B_K(mu approx 2 GeV)=0.602(38) in\nquenched QCD which is consistent with previous calculations. We also find\nratios of decay constants that are consistent with experiment, within our\nstatistical errors. Our initial results indicate good scaling behavior and\nsupport expectations that O(a) errors are exponentially suppressed in low\nenergy (E<< a^{-1}) observables. It is also shown that the axial current\nnumerically satisfies the lattice analog of the usual continuum axial Ward\nidentity and that the matrix element of the four quark operator needed for B_K\nexhibits excellent chiral behavior."
    },
    {
        "anchor": "New Numerical Methods for Quantum Field Theories on the Continuum: The Source Galerkin Method is a new numerical technique that is being\ndeveloped to solve Quantum Field Theories on the continuum. It is not based on\nMonte Carlo techniques and has a measure to evaluate relative errors. It\npromises to increase the accuracy and speed of calculations, and takes full\nadvantage of symmetries of the theory. The application of this method to the\nnon-linear sigma model is outlined.",
        "positive": "The Rome Approach to Chirality: Some general considerations on the problem of non perturbative definition of\nChiral Gauge Theories are presented and exemplified within the particular\nproposal known as the Rome Approach."
    },
    {
        "anchor": "Universal formula for the flavor non-singlet axial-vector current from\n  the gradient flow: By employing the gradient/Wilson flow, we derive a universal formula that\nexpresses a correctly normalized flavor non-singlet axial-vector current of\nquarks. The formula is universal in the sense that it holds independently of\nregularization and especially holds with lattice regularization. It is also\nconfirmed that, in the lowest non-trivial order of perturbation theory, the\ntriangle diagram containing the formula and two flavor non-singlet vector\ncurrents possesses non-local structure that is compatible with the triangle\nanomaly.",
        "positive": "Topology and higher dimensional representations: SU(3) gauge theory in the 2-index symmetric (sextet) and fundamental\nrepresentations is considered in symmetric and periodic boxes. Using the\noverlap formulation in the quenched approximation it is shown that the\ntopological charge obtained from the sextet index theorem always leads to an\ninteger value and agrees with the charge obtained from the fundamental index\ntheorem in the continuum. At larger lattice spacing configurations exist with\nfractional topological charge if the sextet index is used but these are lattice\nartifacts and the probability of finding such a configuration rapidly\napproaches zero. By considering the decomposition of the sextet representation\nwith respect to an SU(2) subgroup it is shown that the SU(2) adjoint index\ntheorem leads to integer charge as well. We conclude that the non-zero value of\nthe bilinear gaugino condensate in N=1 super-Yang-Mills theory cannot be\nattributed to configurations with fractional topological charge once periodic\nboundary conditions are imposed."
    },
    {
        "anchor": "B-physics from the ratio method with Wilson twisted mass fermions: We present a precise lattice QCD determination of the b-quark mass, of the B\nand Bs decay constants and first preliminary results for the B-mesons bag\nparameter. Simulations are performed with Nf = 2 Wilson twisted mass fermions\nat four values of the lattice spacing and the results are extrapolated to the\ncontinuum limit. Our calculation benefits from the use of improved\ninterpolating operators for the B-mesons and employs the so-called ratio\nmethod. The latter allows a controlled interpolation at the b-quark mass\nbetween the relativistic data around and above the charm quark mass and the\nexactly known static limit.",
        "positive": "Finite temperature QCD phase transition with 3 flavors of M\u00f6bius\n  domain wall fermions: We investigate the finite temperature QCD phase transition with three\ndegenerate quark flavors using M\\\"{o}bius domain wall fermions. To explore the\norder of phase transition on the lower left corner of Columbia plot and if\npossible, to locate the critical endpoint we performed simulations at\ntemperatures around 181 and 121 MeV with lattice spacing $a=0.1361(20)$ fm\ncorresponding to temporal lattice extent $N_{\\tau}=8,12$ with varying quark\nmass for two different volumes with aspect ratios $N_{\\sigma}/N_{\\tau}$ ranging\nfrom 2 to 3. By analyzing the volume and mass dependence of the chiral\ncondensate, disconnected chiral susceptibility and Binder cumulant we find that\nthere is a crossover at $m_q^{\\mathrm{\\overline {MS}}}(2\\, \\mathrm{GeV}) \\sim\n44\\, \\mathrm{MeV}$ for $\\mathrm{T_{pc}}\\sim$ 181 MeV, At temperature 121 MeV,\nthe binder cumulant suggests a crossover at $m_q^{\\mathrm{\\overline {MS}}}(2\\,\n\\mathrm{GeV}) \\sim 3.7\\, \\mathrm{MeV}$, although a study of volume dependence\nwould be important to confirm this."
    },
    {
        "anchor": "Perturbative and non-perturbative studies of the SU(2)-Higgs model on\n  lattices with asymmetric lattice spacings: We present a calculation of the O(g^2,\\lambda) perturbative corrections to\nthe coupling anisotropies of the SU(2)-Higgs model on lattices with asymmetric\nlattice spacings. These corrections are obtained by a one-loop calculation\nrequiring the rotational invariance of the gauge and Higgs boson propagators in\nthe continuum limit. The coupling anisotropies are also determined from\nnumerical simulations of the model on appropriate lattices. The one-loop\nperturbation theory and the simulation results agree with high accuracy. It is\ndemonstrated that rotational invariance is also restored for the static\npotential determined from space-space and space-time Wilson loops.",
        "positive": "Testing new strategies in finite density: A new approach for non zero chemical potential simulations is tested in the\nGross-Neveu model for infinite flavor number, where the critical line is\nreconstructed in a large $\\mu/T$ interval. A comparison with results from\nstandard imaginary chemical potential approach as well as first results for\n$N_f=4$ QCD are presented."
    },
    {
        "anchor": "Global symmetry breaking in gauge theories: the case of multiflavor\n  scalar chromodynamics: Universal features of continuous phase transitions can be investigated by\nstudying the $\\phi^4$ field theory with the corresponding global symmetry\nbreaking pattern. When gauge symmetries are present, the same technique is\nusually applied to a gauge-invariant order parameter field, as in the\nPisarski-Wilczek analysis of the QCD chiral phase transition. Gauge fields are\nthus assumed to be irrelevant in the effective critical model, a fact that is\nhowever far from trivial. We will investigate the validity of this approach\nusing three-dimensional scalar lattice models with non-abelian global and local\nsymmetries, for which critical exponents and scaling functions can be\nnumerically determined with high accuracy.",
        "positive": "Determination of the properties of vector mesons in external magnetic\n  field by Quenched $SU(3)$ Lattice QCD: We investigate the ground state energies of vector $\\rho^{\\pm}$ and $K^{\\pm\n*}$ mesons depending on the magnetic field value in the $SU(3)$ lattice gauge\ntheory. It has been shown that the energy of a vector particle depends on its\nspin projection on the field axis. The magnetic dipole polarizability and\nhyperpolarizabilities give significant contributions to the energy value which\nprevents the formation of the charged vector meson condensate at high magnetic\nfields. We calculate the g-factor of $\\rho^{\\pm}$ and $K^{\\pm*}$ mesons and the\ndipole magnetic polarizability of $\\rho^{\\pm}$ mesons."
    },
    {
        "anchor": "B-physics with $N_f=2$ Wilson fermions: We report the final results of the ALPHA collaboration for some B-physics\nobservables: $f_B$, $f_{B_s}$ and $m_b$. We employ CLS configurations with 2\nflavors of $O(a)$ improved Wilson fermions in the sea and pion masses ranging\ndown to 190 MeV. The b-quark is treated in HQET to order $1/m_b$. The\nrenormalization, the matching and the improvement were performed\nnon-perturbatively, and three lattice spacings reaching $a=0.048$ fm are used\nin the continuum extrapolation.",
        "positive": "Probing the finite temperature phase transition with Nf=2\n  nonperturbatively improved Wilson fermions: The critical temperature and the nature of the QCD finite temperature phase\ntransition are determined for Nf=2 dynamical flavors of nonperturbatively\nimproved Wilson fermions. The calculations are performed on large lattices with\ntemporal extents Nt=12, 10 and 8, and lattice spacings down to a = 0.075 fm. We\nfind the deconfinement and chiral phasetransitions to take place at the same\ntemperature. Our results are in broad agreement with a second order phase\ntransition in the chiral limit. The critical temperature at the physical quark\nmass is found to be Tc = 174(3)(6) MeV."
    },
    {
        "anchor": "The Nuclear Yukawa Model on a Lattice: We present the results of the quantum field theory approach to nuclear Yukawa\nmodel obtained by standard lattice techniques. We have considered the simplest\ncase of two identical fermions interacting via a scalar meson exchange.\nCalculations have been performed using Wilson fermions in the quenched\napproximation. We found the existence of a critical coupling constant above\nwhich the model cannot be numerically solved. The range of the accessible\ncoupling constants is below the threshold value for producing two-body bound\nstates. Two-body scattering lengths have been obtained and compared to the non\nrelativistic results.",
        "positive": "Induced Chern-Simons term in lattice QCD at finite temperature: The general conditions for the Chern-Simons action to be induced as a\nnonuniversal contribution of fermionic determinant are formulated in the finite\ntemperature lattice QCD. The dependence of the corresponding action coefficient\non nonuniversal parameters (chemical potentials, vacuum features, etc. ) is\nexplored. Special attention is paid to the role of $A_0$-condensate if it is\navailable in this theory."
    },
    {
        "anchor": "Gauge-fixed Lattice QCD and the dispersion relation of Wilson fermions: We show that, when investigating Wilson-fermions correlation functions on the\nlattice, one is bound to encounter major difficulties in defining their\ndispersion relation, even at tree level. The problem is indeed quite general\nand, although we stumbled upon it while studying Coulomb-gauge applications, it\nalso affects gauge fixed studies in covariant gauges, including their most\npopular version, Landau gauge. In this paper we will discuss a solution to this\nproblems based on a redefinition of the kinematic momentum of the fermion.",
        "positive": "Mean link versus average plaquette tadpoles in lattice NRQCD: We compare mean-link and average plaquette tadpole renormalization schemes in\nthe context of the quarkonium hyperfine splittings in lattice NRQCD.\nSimulations are done for the three quarkonium systems $c\\bar c$, $b\\bar c$, and\n$b\\bar b$. The hyperfine splittings are computed both at leading and at\nnext-to-leading order in the relativistic expansion. Results are obtained at a\nlarge number of lattice spacings. A number of features emerge, all of which\nfavor tadpole renormalization using mean links. This includes much better\nscaling of the hyperfine splittings in the three quarkonium systems. We also\nfind that relativistic corrections to the spin splittings are smaller with\nmean-link tadpoles, particularly for the $c\\bar c$ and $b\\bar c$ systems. We\nalso see signs of a breakdown in the NRQCD expansion when the bare quark mass\nfalls below about one in lattice units (with the bare quark masses turning out\nto be much larger with mean-link tadpoles)."
    },
    {
        "anchor": "Absence of sign problem in two-dimensional N=(2,2) super Yang-Mills on\n  lattice: We show that N=(2,2) SU(N) super Yang-Mills theory on lattice does not have\nsign problem in the continuum limit, that is, under the phase-quenched\nsimulation phase of the determinant localizes to 1 and hence the phase-quench\napproximation becomes exact. Among several formulations, we study models by\nCohen-Kaplan-Katz-Unsal (CKKU) and by Sugino. We confirm that the sign problem\nis absent in both models and that they converge to the identical continuum\nlimit without fine tuning. We provide a simple explanation why previous works\nby other authors, which claim an existence of the sign problem, do not capture\nthe continuum physics.",
        "positive": "Critical Equalities for Potts Models: We apply a simple analytical criterion for locating critical temperatures to\nPotts models on square and triangular lattices. In the self-dual case, i.e. on\nthe square lattice we reproduce known exact values of the critical temperature\nand derive the internal energy of the model at the critical point. For the\nPotts model on the triangular lattice we obtain very good numerical estimate of\nthe critical temperature and also of the internal energy at the critical point."
    },
    {
        "anchor": "The isospin breaking effect on baryons with Nf=2 domain wall fermions: We study the isospin breaking effect on octet baryons. Using the two-flavor\ndynamical domain-wall QCD configurations combined with the quenched non-compact\nQED configurations, the electromagnetic mass splittings between isomultiplets\n(p, n), (Sigma^+, Sigma^0, Sigma^-), (Xi^0, Xi^-) are investigated. We evaluate\nthe main source of statistical fluctuations in the two-point correlation\nfunction, and find that the elimination of O(e) fluctuation (e: the QED charge)\nis essential to extract the signal. Preliminary results for $m_p - m_n$ as well\nas other mass splittings are presented. Possible origin of systematic\nuncertainty is also discussed.",
        "positive": "Light Hadron Spectroscopy on Coarse Lattices with O(a^2) Mean-Field\n  Improved Actions: The masses and dispersions of light hadrons are calculated in lattice QCD\nusing an O(a^2) tadpole-improved gluon action and an O(a^2) tadpole-improved\nnext-nearest-neighbor fermion action originally proposed by Hamber and Wu. Two\nlattices of constant volume with lattice spacings of approximately 0.40 fm and\n0.24 fm are considered. The results reveal some scaling violations at the\ncoarser lattice spacing on the order of 5%. At the finer lattice spacing, the\ncalculated mass ratios reproduce state-of-the-art results using unimproved\nactions. Good dispersion and rotational invariance up to momenta of pa ~ 1 are\nalso found. The relative merit of alternative choices for improvement operators\nis assessed through close comparisons with other plaquette-based\ntadpole-improved actions."
    },
    {
        "anchor": "The infrared dynamics of Minimal Walking Technicolor: We study the gauge sector of Minimal Walking Technicolor, which is an SU(2)\ngauge theory with nf=2 flavors of Wilson fermions in the adjoint\nrepresentation. Numerical simulations are performed on lattices Nt x Ns^3, with\nNs ranging from 8 to 16 and Nt=2Ns, at fixed \\beta=2.25, and varying the\nfermion bare mass m0, so that our numerical results cover the full range of\nfermion masses from the quenched region to the chiral limit. We present results\nfor the string tension and the glueball spectrum. A comparison of mesonic and\ngluonic observables leads to the conclusion that the infrared dynamics is given\nby an SU(2) pure Yang-Mills theory with a typical energy scale for the spectrum\nsliding to zero with the fermion mass. The typical mesonic mass scale is\nproportional to, and much larger than this gluonic scale. Our findings are\ncompatible with a scenario in which the massless theory is conformal in the\ninfrared. An analysis of the scaling of the string tension with the fermion\nmass towards the massless limit allows us to extract the chiral condensate\nanomalous dimension \\gamma*, which is found to be \\gamma*=0.22+-0.06.",
        "positive": "Evidence for the reality of singular configurations in SU(2) gauge\n  theory: We consider the SU(2) lattice gauge model and investigate numerically the\ncontinuum limit of the simple center vortices which are singular configurations\nof the gauge fields. We found that the vortices remain alive in the continuum\ntheory. Also we investigate the Creutz ratio and found that for all $\\beta$ it\nvanishes for those field configurations which do not contain the simple center\nvortices inside the considered Wilson loop. It leads us to the conclusion that\nthese singular field configurations play a real role in the continuum theory."
    },
    {
        "anchor": "Fitting a sum of exponentials to lattice correlation functions using a\n  non-uniform prior: Excited states are extracted from lattice correlation functions using a\nnon-uniform prior on the model parameters. Models for both a single exponential\nand a sum of exponentials are considered, as well as an alternate model for the\northogonalization of the correlation functions. Results from an analysis of\ntorelon and glueball operators indicate the Bayesian methodology compares well\nwith the usual interpretation of effective mass tables produced by a\nvariational procedure. Applications of the methodology are discussed.",
        "positive": "Lifting flat directions in lattice supersymmetry: We present a procedure to improve the lattice definition of $\\mathcal N = 4$\nsupersymmetric Yang--Mills theory. The lattice construction necessarily\ninvolves U(1) flat directions, and we show how these can be lifted without\nviolating the exact lattice supersymmetry. The basic idea is to modify the\nequations of motion of an auxiliary field, which determine the moduli space of\nthe system. Applied to numerical calculations, the resulting improved lattice\naction leads to dramatically reduced violations of supersymmetric Ward\nidentities and much more rapid approach to the continuum limit."
    },
    {
        "anchor": "Finite Temperature Phase Diagrams of Gauge Theories: We discuss finite temperature phase diagrams of SU(N) gauge theory with\nmassless fermions as a function of the number of fermion flavors. Inside the\nconformal window we find a phase boundary separating two different conformal\nphases. Below the conformal window we find different phase structures depending\non if the beta function of the theory has a first or higher order zero at the\nlower boundary of the conformal window. We also outline how the associated\nbehaviors will help in distinguishing different types of theories using lattice\nsimulations.",
        "positive": "Hadronic Interactions from Lattice QCD: We present an overview of recent efforts to calculate the interactions among\nhadrons using lattice QCD. After outlining the techniques that are used to\nextract scattering parameters, we detail the latest calculations of meson-meson\nscattering, baryon-baryon scattering and multi-meson systems obtained with\ndomain-wall valence quarks on the staggered MILC lattices by the NPLQCD\ncollaboration. Estimates of the computational resources required to achieve\nprecision results in the baryon sector are presented."
    },
    {
        "anchor": "Landau gauge gluon vertices from Lattice QCD: In lattice QCD the computation of one-particle irreducible (1PI) Green's\nfunctions with a large number (> 2) of legs is a challenging task. Besides\ntuning the lattice spacing and volume to reduce finite size effects, the\nproblems associated with the estimation of higher order moments via Monte Carlo\nmethods and the extraction of 1PI from complete Green's functions are\nlimitations of the method. Herein, we address these problems revisiting the\ncalculation of the three gluon 1PI Green's function.",
        "positive": "Revisiting glueball wave functions at zero and finite temperature: We study the sizes and thermal properties of glueballs in a three dimensional\ncompact Abelian gauge model on improved lattice. We predict the radii of $\\sim\n0.60$ and $\\sim 1.12$ in the units of string tension, or $\\sim 0.28$ and $\\sim\n0.52$ fm, for the scalar and tensor glueballs, respectively. We perform a well\ncontrolled extrapolation of the radii to the continuum limit and observe that\nour results agree with the predicted values. Using Monte Carlo simulations, we\nextract the pole-mass of the lowest scalar and tensor glueballs from the\ntemporal correlators at finite temperature. We see a clear evidence of the\ndeconfined phase, and the transition appears to be similar to that of the\ntwo-dimensional XY model as expected from universality arguments. Our results\nshow no significant changes in the glueball wave functions and masses in the\ndeconfined phase."
    },
    {
        "anchor": "Preliminary lattice study of the I=1 $K \\bar{K}$ scattering length: The s-wave kaon-antikaon ($K \\bar{K}$) elastic scattering length is\ninvestigated by lattice simulation using pion masses $m_\\pi = 330 - 466$ MeV.\nThrough moving wall sources without gauge fixing, we calculate $K \\bar{K}$\nfour-point correlation functions for isospin I=1 channel in the \"Asqtad\"\nimproved staggered fermion formulation, and observe a clear signal of\nattraction, which is consistent with other pioneering lattice studies on $K\n\\bar{K}$ potential. Extrapolating $K \\bar{K}$ scattering length to the physical\npoint, we obtain $m_{K} a^{I=1}_{K\\bar{K}} = 0.211(33)$. These simulations are\nperformed with MILC gauge configurations at lattice spacing $a \\approx 0.15$\nfm.",
        "positive": "Charm quark system in 2+1 flavor lattice QCD using the PACS-CS\n  configurations: We study heavy-heavy and heavy-light quark systems for charm with a\nrelativistic heavy quark action in 2+1 flavor lattice QCD. Configurations are\ngenerated by the PACS-CS Collaboration at the lattice spacing is $a=0.09$ fm\nwith the lattice size of $32^3\\times 64$ employing the $O(a)$-improved Wilson\nquark action and the Iwasaki gauge action. We present preliminary results for\nthe charmonium spectrum and the $D$ and $D_s$ meson decay constants evaluated\nat 3.5 MeV$< m_{\\rm ud}<$ 12 MeV with $m_{\\rm s}$ around the physical value. We\ninvestigate the dynamical quark mass dependences of the hyperfine and the\norbital splittings. The decay constants are compared with the recent\nexperimental values."
    },
    {
        "anchor": "Hypercubic Effects in semileptonic $D \\to \u03c0$ decays on the lattice: We present a lattice determination of the vector and scalar form factors of\nthe semileptonic $D \\to \\pi \\ell \\nu$ decays, which are relevant for the\nextraction of the CKM matrix element $\\lvert V_{cd} \\rvert$ from experimental\ndata. Our analysis is based on the gauge configurations produced by the\nEuropean Twisted Mass Collaboration with $N_f = 2 + 1 + 1$ flavors of dynamical\nquarks. We simulated at three different values of the lattice spacing and with\npion masses as small as 210 MeV. Quark momenta are injected on the lattice\nusing non-periodic boundary conditions. The matrix elements of both vector and\nscalar currents are determined for a plenty of kinematical conditions in which\nparent and child mesons are either moving or at rest. Lorentz symmetry breaking\ndue to hypercubic effects is clearly observed in the data and included in the\ndecomposition of the current matrix elements in terms of additional form\nfactors. Our preliminary estimate for the vector form factor at zero 4-momentum\ntransfer is $f_+^{D \\to \\pi}(0) = 0.631\\,(40)$, which can be compared with the\nlatest FLAG average $f_+^{D \\to \\pi}(0) = 0.666\\,(29)$ available only at $N_f =\n2 + 1$.",
        "positive": "Center Vortices and Monopoles without lattice Gribov copies: We construct a smooth gauge for the adjoint field which is free of\nambiguities on the lattice. In this Laplacian Center Gauge, center vortices and\nmonopoles appear together as local gauge defects. A numerical study of center\nvortices in SU(2) and SU(3) supports equality of the $Z_N$ and SU(N) string\ntensions in the continuum limit, and only then."
    },
    {
        "anchor": "High Spin Glueballs from the Lattice: We discuss the principles underlying higher spin glueball calculations on the\nlattice. For that purpose, we develop numerical techniques to rotate Wilson\nloops by arbitrary angles in lattice gauge theories close to the continuum. As\na first application, we compute the glueball spectrum of the SU(2) gauge theory\nin 2+1 dimensions for both parities and for spins ranging from 0 up to 4\ninclusive. We measure glueball angular wave functions directly, decomposing\nthem in Fourier modes and extrapolating the Fourier coefficients to the\ncontinuum. This allows a reliable labelling of the continuum states and gives\ninsight into the way rotation symmetry is recovered. As one of our results, we\ndemonstrate that the D=2+1 SU(2) glueball conventionally labelled as J^P = 0^-\nis in fact 4^- and that the lightest ``J=1'' state has, in fact, spin 3.",
        "positive": "Latest Results from Heavy Quark Simulations: The status of b-bbar and c-cbar calculations, numerical and analytic, are\nreviewed. The extraction of alpha_s and quark masses from spectrum calculations\nis discussed. The NRQCD and Improved Heavy Wilson formulations of heavy quarks\nare compared, and recent calculations using a Heavy Staggered formulation are\ndiscussed."
    },
    {
        "anchor": "Ginsparg-Wilson fermions: practical aspects and applications: I review recent progress in the implementation of lattice fermions satisfying\nthe Ginsparg-Wilson relation and some physical applications.",
        "positive": "Kramers Equation Algorithm with Kogut-Susskind Fermions on Lattice: We compare the performance of the Kramers Equation Monte Carlo (KMC)\nAlgorithm with that of the Hybrid Monte Carlo (HMC) algorithm for numerical\nsimulations with dynamical Kogut-Susskind fermions. Using the lattice\nGross-Neveu model in 2 space-time dimensions, we calculate the integrated\nautocorrelation time of different observables at a number of couplings in the\nscaling region on 16^2 and 32^2 lattices while varying the parameters of the\nalgorithms for optimal performance. In our investigation the performance of KMC\nis always significantly below than that of HMC for the observables used. We\nalso stress the importance of having a large number of configurations for the\naccurate estimation of the integrated autocorrelation time."
    },
    {
        "anchor": "B Semileptonic Decays at High Recoil Momentum: We explore the possibility of studying $B\\to\\pi l\\nu$ semileptonic decays at\nlarge recoil momentum. Our methods include the use of a random-wall source for\nthe pion to reduce statistical errors, and different smearing functions are\nused for the B meson to improve the overlap with the ground state. We observe,\nin general, a factor of 3-4 improvement in the signal-to-noise ratio in\ncorrelation functions if random-wall propagators are used.",
        "positive": "Simulation of Supersymmetric Models with a Local Nicolai Map: We study the numerical simulation of supersymmetric models having a local\nNicolai map. The mapping can be regarded as a stochastic equation and its\nnumerical integration provides an algorithm for the simulation of the original\nmodel. In this paper, the method is discussed in details and applied to\nexamples in 0+1 and 1+1 dimensions."
    },
    {
        "anchor": "Volume Dependence of N-Body Bound States: We derive the finite-volume correction to the binding energy of an N-particle\nquantum bound state in a cubic periodic volume. Our results are applicable to\nbound states with arbitrary composition and total angular momentum, and in any\nnumber of spatial dimensions. The only assumptions are that the interactions\nhave finite range. The finite-volume correction is a sum of contributions from\nall possible breakup channels. In the case where the separation is into two\nbound clusters, our result gives the leading volume dependence up to\nexponentially small corrections. If the separation is into three or more\nclusters, there is a power-law factor that is beyond the scope of this work,\nhowever our result again determines the leading exponential dependence. We also\npresent two independent methods that use finite-volume data to determine\nasymptotic normalization coefficients. The coefficients are useful to determine\nlow-energy capture reactions into weakly bound states relevant for nuclear\nastrophysics. Using the techniques introduced here, one can even extract the\ninfinite-volume energy limit using data from a single-volume calculation. The\nderived relations are tested using several exactly solvable systems and\nnumerical examples. We anticipate immediate applications to lattice\ncalculations of hadronic, nuclear, and cold atomic systems.",
        "positive": "Exclusive Channel Study of the Muon HVP: The Hadronic Vacuum Polarization (HVP) is a dominant contribution to the\ntheoretical uncertainty of the muon anomalous magnetic moment. The uncertainty\nin a lattice QCD calculation of the connected light-quark contribution to the\nHVP is dominated by the long-distance region of the vector correlation\nfunction. Explicit studies of the exclusive channels of the HVP diagram make it\npossible to reconstruct the long-distance behavior of the correlation function.\nThis removes most of the statistical uncertainty of the correlation function.\nIn these proceedings, preliminary results of an exclusive study of the isospin\nsymmetric connected-only vector-vector correlation function using a hybrid of\ndistillation and A2A techniques are presented. The computation is performed on\n2+1 flavor M\\\"obius Domain Wall Fermion ensembles with physical pion mass.\nReconstruction of the long-distance correlation function will enable\nlattice-only calculations of the HVP to achieve precision similar to estimates\nof the HVP from the R-ratio method on the timescale of the new experimental\nmeasurements of the muon anomalous magnetic moment."
    },
    {
        "anchor": "Exact blocking formulas for spin and gauge models: Using the example of the two-dimensional (2D) Ising model, we show that in\ncontrast to what can be done in configuration space, the tensor renormalization\ngroup (TRG) formulation allows one to write exact, compact, and manifestly\nlocal blocking formulas and exact coarse grained expressions for the partition\nfunction. We argue that similar results should hold for most models studied by\nlattice gauge theorists. We provide exact blocking formulas for several 2D spin\nmodels (the O(2) and O(3) sigma models and the SU(2) principal chiral model)\nand for the 3D gauge theories with groups Z_2, U(1) and SU(2). We briefly\ndiscuss generalizations to other groups, higher dimensions and practical\nimplementations.",
        "positive": "Scattering of dark pions in an Sp(4) gauge theory: In this work we consider strongly interacting dark matter candidates as\ncomposite states of $N_f=2$ fermions charged under a dark $Sp(4)$ gauge group\nin the fundamental representation. We give expressions that allow the\ncalculation of correlation functions of two pseudo-Nambu-Goldstone-bosons with\nlattice field theory and present first results on the scattering phase shift in\nthe isospin-2 channel in the theory from first principles. We give a lower\nlimit on the dark matter particle mass by comparing our results with\nastrophysical constraints on the cross-section."
    },
    {
        "anchor": "Scale hierarchy in high-temperature QCD: Because of asymptotic freedom, QCD becomes weakly interacting at high\ntemperature: this is the reason for the transition to a deconfined phase in\nYang-Mills theory at temperature $T_c$. At high temperature $T \\gg T_c$, the\nsmallness of the running coupling $g$ induces a hierachy betwen the \"hard\",\n\"soft\" and \"ultrasoft\" energy scales $T$, $g T$ and $g^2 T$. This hierarchy\nallows for a very successful effective treatment where the \"hard\" and the\n\"soft\" modes are successively integrated out. However, it is not clear how high\na temperature is necessary to achieve such a scale hierarchy.\n  By numerical simulations, we show that the required temperatures are\nextremely high. Thus, the quantitative success of the effective theory down to\ntemperatures of a few $T_c$ appears surprising a posteriori.",
        "positive": "QCD AT FINITE BARYON DENSITY WITH t-ASYMMETRIC FERMIONS: Susskind's continuous-time fermions, with two flavours, can be latticized\nusing a one-sided time derivative. We are presently investigating the\ninteracting case, where we hope to find the onset at finite $\\mu$ at the right\nplace due to the reduced number of flavours. As for these fermions there is\nonly a discrete chiral symmetry left over, the lightness of pions in the broken\nphase has to be investigated."
    },
    {
        "anchor": "INvestigation Of The Biconjugate Gradient Algorithm For The Inversion Of\n  Fermion Matrices: An algorithm for the numerical inversion of large matrices, the biconjugate\ngradient algorithm (BGA), is investigated in view of its use for Monte Carlo\nsimulations of fermionic field theories. It is compared with the usual\nconjugate gradient algorithm (CGA) and the minimal residue algorithm (MRA)\nwithin a Higgs-Yukawa model including mirror fermions. For this model it can be\nshown that BGA represents an improvement under certain circumstances where the\nother two slow down.",
        "positive": "Towards the physical point hadronic vacuum polarisation from Moebius DWF: We present steps towards the computation of the leading-order hadronic\ncontribution to the muon anomalous magnetic moment on RBC/UKQCD physical point\nDWF ensembles. We discuss several methods for controlling and reducing\nuncertainties associated to the determination of the HVP form factor."
    },
    {
        "anchor": "Continuing Progress on a Lattice QCD Software Infrastructure: We report on the progress of the software effort in the QCD Application Area\nof SciDAC. In particular, we discuss how the software developed under SciDAC\nenabled the aggressive exploitation of leadership computers, and we report on\nprogress in the area of QCD software for multi-core architectures.",
        "positive": "Towards 4-loop NSPT result for a 3-dimensional condensate-contribution\n  to hot QCD pressure: Thanks to dimensional reduction, the contributions to the hot QCD pressure\ncoming from so-called soft modes can be studied via an effective\nthree-dimensional theory named Electrostatic QCD (spatial Yang-Mills fields\nplus an adjoint Higgs scalar). The poor convergence of the perturbative series\nwithin EQCD suggests to perform lattice measurements of some of the associated\ngluon condensates. These turn out, however, to be plagued by large\ndiscretization artifacts. We discuss how Numerical Stochastic Perturbation\nTheory can be exploited to determine the full lattice spacing dependence of one\nof these condensates up to 4-loop order, and sharpen our tools on a concrete\n2-loop example."
    },
    {
        "anchor": "B and D meson decay constants from 2+1 flavor improved staggered\n  simulations: We give an update on simulation results for the decay constants f_B, f_{B_s},\nf_D and f_{D_s}. These decay constants are important for precision tests of the\nstandard model, in particular entering as inputs to the global CKM unitarity\ntriangle fit. The results presented here make use of the MILC (2+1)-flavor\nasqtad ensembles, with heavy quarks incorporated using the clover action with\nthe Fermilab method. Partially quenched, staggered chiral perturbation theory\nis used to extract the decay constants at the physical point. In addition, we\ngive error projections for a new analysis in progress, based on an extended\ndata set.",
        "positive": "Is the Up Quark Massless?: Several lattice calculations of a combination of the low energy constants of\nthe chiral Lagrangian, 2\\alpha_8-\\alpha_5, are presented. This combination is\ncritical for the preclusion of a massless up quark. The result found is\n2\\alpha_8-\\alpha_5 = 0.115 \\pm 0.051^{stat} \\pm 0.25^{syst}, which is well\noutside of the range allowed by a massless up quark."
    },
    {
        "anchor": "Scaling behavior of $f_{B}$ with NRQCD: We investigate the scaling behavior of the $B$ meson decay constant $f_B$ and\n$f_{B_{s}}$ at $\\beta$$=$$5.7, 5.9, 6.1$, employing the NRQCD heavy quark\naction and the clover light quark action. Mixing effect from dimension-4\noperator in the heavy-light axial-vector current is studied, and we find that\nthe $a$ dependence of $f_B$ is significantly reduced. Our preliminary result\nfor the decay constants in the quenched approximation is\n$f_{B}$$=$$162(^{+35}_{-18})$ MeV, $f_{B_{s}}$$=$$190(^{+40}_{-19})$ MeV, and\n$f_{B_{s}}/f_{B}$$=$$1.18(^{+6}_{-6})$.",
        "positive": "Mesonic String of Diquark-Quark Configuration at Finite Temperature: We investigate the distance and temperatures scale for which the string in\nbaryonic quark configuration approaches the limiting behavior of mesonic\nstrings in pure Yang-Mills SU(3) lattice gauge theory. We calculate and compare\nthe numerical values of the Polyakov loop correlators and the width profile of\nboth diquark-quark $(QQ)Q$ and mesonic $Q\\bar{Q}$ strings. We find the\ndiquark-quark configuration to exhibit an identical behavior to the mesonic\nstring for the potential and energy-density width profile for temperature near\nthe end of QCD plateau. In the vicinity of the deconfinement point; however,\nthe symmetry in the energy-width profile with the meson does not manifest at\nboth short and intermediate distance scales. Moreover, we observe significantly\ndifferent numerical values for Polyakov loop correlators corresponding to each\nsystem. The splitting of the two identical system suggest that, in the high\ntemperature region of the confined phase of QCD, the subsisted baryonic\ndecouplet states overlap with the excited mesonic spectrum yielding the\ndiquark-quark symmetry with the meson inexact in a small enough neighborhood of\nthe critical point $T_{c}$."
    },
    {
        "anchor": "Search for Fermion Actions on Hyperdiamond Lattices: Fermions moving in a two-dimensional honeycomb lattice (graphene) have, at\nlow energies, chiral symmetry. Generalizing this construction to four\ndimensions potentially provides fermions with chiral symmetry and only the\nminimal fermion doubling demanded by the Nielsen-Ninomiya no-go theorem. The\npractical usefulness of such fermions hinges on whether the action has a\nnecessary set of discrete symmetries of the lattice. If this is the case, one\navoids the generation of dimension three and four operators which require fine\ntuning. We construct hyperdiamond lattice actions with enough symmetries to\nexclude fine tuning; however, they produce multiple doublings. The limit where\nthe actions exhibit minimal doubling does not possess the requisite symmetry.",
        "positive": "Study of shear viscosity of SU (2)-gluodynamics within lattice\n  simulation: This paper is devoted to the study of two-point correlation function of the\nenergy-momentum tensor T_{12}T_{12} for SU(2)-gluodynamics within lattice\nsimulation of QCD. Using multilevel algorithm we carried out the measurement of\nthe correlation function at the temperature T/T_c = 1.2. It is shown that\nlattice data can be described by spectral functions which interpolate between\nhydrodynamics at low frequencies and asymptotic freedom at high frequencies.\nThe results of the study of spectral functions allowed us to estimate the ratio\nof shear viscosity to the entropy density {\\eta}/s = 0.134 +- 0.057."
    },
    {
        "anchor": "Future of Chiral Extrapolations with Domain Wall Fermions: I discuss the constraints on the lattice spacing, a, the quark masses, m, the\nbox size, L, and particularly the residual mass, m_res, such that one can\nsuccessfully calculate phenomenologically interesting quantities using Domain\nWall fermions (DWF). The constraints on a, m, and L are largely common with\nother improved fermion discretizations, and I emphasize that the improved\nchiral symmetry of DWF does not remove the need for simulations with a\nsignificant range of lattice parameters. Concerning m_res, I compare the\nanalysis of chiral symmetry breaking to that with Wilson fermions, emphasizing\nthat DWF are better than simply Wilson fermions with each chiral symmetry\nbreaking effect reduced by a common factor. I then discuss the impact of\nnon-zero m_res both on generic hadronic quantities, and on matrix elements\nwhich involve mixing with lower dimension operators.",
        "positive": "2+1 flavor fine lattice simulation at finite temperature with\n  domain-wall fermions: Simulations for the thermodynamics of the 2+1 flavor QCD are performed\nemploying chiral fermions. The use of M\\\"obius domain-wall fermions with\nstout-link smearing is more effective on the finer lattices where all the\nrelevant chiral symmetries are realized more accurately. We report on the\ninitial simulations near the (pseudo) critical point using the line of constant\nphysics with an average $ud$ quark mass slightly heavier than physical at\n$a\\lesssim 0.1$ fm."
    },
    {
        "anchor": "A relativistic, model-independent, three-particle quantization condition: We present a generalization of Luescher's relation between the finite-volume\nspectrum and scattering amplitudes to the case of three particles. We consider\na relativistic scalar field theory in which the couplings are arbitrary aside\nfrom a Z2 symmetry that removes vertices with an odd number of particles. The\ntheory is assumed to have two-particle phase shifts that are bounded by \\pi/2\nin the regime of elastic scattering. We determine the spectrum of the\nfinite-volume theory from the poles in the odd-particle-number finite-volume\ncorrelator, which we analyze to all orders in perturbation theory. We show that\nit depends on the infinite-volume two-to-two K-matrix as well as a nonstandard\ninfinite-volume three-to-three K-matrix. A key feature of our result is the\nneed to subtract physical singularities in the three-to-three amplitude and\nthus deal with a divergence-free quantity. This allows our initial, formal\nresult to be truncated to a finite dimensional determinant equation. At\npresent, the relation of the three-to-three K-matrix to the corresponding\nscattering amplitude is not known, although previous results in the\nnon-relativistic limit suggest that such a relation exists.",
        "positive": "Electromagnetic form factors of the proton and neutron from $N_f = 2 +\n  1$ lattice QCD: We present results for the electromagnetic form factors of the proton and\nneutron computed on the Coordinated Lattice Simulations (CLS) ensembles with\n$N_f = 2 + 1$ flavors of $\\mathcal{O}(a)$-improved Wilson fermions and an\n$\\mathcal{O}(a)$-improved conserved vector current. In order to estimate the\nexcited-state contamination, we employ several source-sink separations and\napply the summation method. The quark-disconnected diagrams entering the\nisoscalar quantities are computed explicitly. For this purpose, a stochastic\nestimation based on the one-end trick is performed, in combination with a\nfrequency-splitting technique and the hopping-parameter expansion. By these\nmeans, we obtain a clear signal for the form factors including the\nquark-disconnected contributions, which have a statistically significant effect\non our results. From the $Q^2$-dependence of the form factors, we determine the\nelectric and magnetic charge radii and the magnetic moments of the proton and\nneutron. The chiral interpolation is carried out by simultaneously fitting the\npion mass and $Q^2$-dependence of our form factor data directly to the\nexpressions resulting from covariant chiral perturbation theory including\nvector mesons. To assess the influence of systematic effects, we average over\nvarious cuts in the pion mass and the momentum transfer, as well as over\ndifferent models for the lattice spacing and finite volume dependence."
    },
    {
        "anchor": "Spectrum of screening masses in the (3+1)D SU(2) pure gauge theory near\n  the critical temperature: We study the spectrum of screening masses in the deconfined phase of (3+1)D\nSU(2) pure gauge theory near criticality and compare it with the spectrum of\nbound states in the broken symmetry phase of the 3D Ising model, which is\nrelated to the gauge theory by universality.",
        "positive": "Infrared Divergent Coulomb Self-Energy in Yang-Mills Theory: It is shown numerically that the Coulomb self-energy of an isolated, color\nnon-singlet source diverges in an infinite volume. This is in accord with the\nGribov Horizon scenario of confinement advocated by Gribov and Zwanziger. It is\nalso shown that this divergence can be attributed to the presence of center\nvortices in thermalized lattice configurations."
    },
    {
        "anchor": "Summary of Super Doubler Approach on Exact Lattice Supersymmetry: We have proposed a lattice SUSY formulation which we may call super doubler\napproach, where chiral fermion species doublers and their bosonic counter parts\nare either identified as super partners or truncated by chiral conditions. We\nclaim that the super symmetry is exactly kept on the lattice. However the\nformulation is nonlocal and breaks lattice translational invariance. We argue\nthat these features cause no fundamental difficulties in the continuum limit.\nAlthough a naive version of this formulation breaks associativity of the\nproduct of fields we have found a modified super doubler approach that recovers\nthe associativity and is applicable to super Yang-Mills theory. It turns out\nthat this formulation is essentially equivalent to the continuum formulation\nand thus keeps all the symmetry exact even at a finite lattice constant.\nInspired by this formulation we propose a non-local lattice field theory\nformulation which is free of chiral fermion problem and has the same exact\nlattice symmetry as continuum theory.",
        "positive": "Charmed Baryon Spectroscopy from lattice QCD for $N_f = 2 + 1$ flavours: In recent years, several charmed baryons have been discovered, with more\nstates likely to be found in the future. We investigate the spectra of singly\nand doubly charmed baryons on the lattice. The spin J=1/2 and J=3/2 states are\ncalculated for both positive and negative parity."
    },
    {
        "anchor": "Study of theta-Vacua in the 2-d O(3) Model: We investigate the continuum limit of the step scaling function in the 2-d\nO(3) model with different theta-vacua. Since we find a different continuum\nvalue of the step scaling function for each value of theta, we can conclude\nthat theta indeed is a relevant parameter of the theory and does not get\nrenormalized non-perturbatively. Furthermore, we confirm the result of the\nconjectured exact S-matrix theory, which predicts the continuum value at theta\n= pi. To obtain high precision data, we use a modified Hasenbusch improved\nestimator and an action with an optimized constraint, which has very small\ncut-off effects. The optimized constraint action combines the standard action\nof the 2-d O(3) model with a topological action. The topological action\nconstrains the angle between neighboring spins and is therefore invariant\nagainst small deformations of the field.",
        "positive": "Optimized $\u03b4$ - Expansion for Lattice U(1) and SU(2) with\n  Interpolating Continuum Action: Embedding the lattice gauge theory into a continuum theory allows to use the\ncontinuum action as trial action in the variational calculation. Only\noriginally divergent graphs contribute. This leads to a very simple scheme\nwhich makes it possible to write down explicit expressions for the plaquette\nenergy $E$ for U(1) in arbitrary space time dimension for the first three\norders of the expansion. For dimensions three and four one can even go up to\nfourth order. This allows a rather thorough empirical investigation of the\nconvergence properties of the $\\delta $-expansion, in particular near the phase\ntransition or the transition region, respectively. As already found in previous\nwork, the principle of minimal sensitivity can be only applied for $\\beta $\nabove a certain value, because otherwise no extremum with respect to the\nvariational parameter exists. One can, however, extend the range of\napplicability down to small $\\beta $, by calculating instead of $E$ some power\n$E^\\kappa $, or by performing an appropriate Pad\\'e transformation. We find\nexcellent agreement with the data for $\\beta $ above the transition region for\nthe second and higher orders. Below the transition region the agreement is\nrather poor in low orders, but quite impressive in fourth order. For SU(2) we\nperformed the calculation up to second order. The agreement with the data is\nsomewhat worse than in the abelian case."
    },
    {
        "anchor": "A Quarkyonic Phase in Dense Two Color Matter?: We present results from simulations of Two Color QCD with two Wilson quark\nflavors in the presence of a quark chemical potential mu at two different\nlattice spacings. The equation of state, conformal anomaly, superfluid order\nparameter and Polyakov line are all discussed. Our results suggest that the\ntransition from hadronic to quark matter, and that from confined to deconfined\nmatter occur at distinct values of mu, consistent with the existence of a\nquarkyonic phase in this model.",
        "positive": "Matter-antimatter coexistence method for finite density QCD toward a\n  solution of the sign problem: Toward the lattice QCD calculation at finite density, we propose\n\"matter-antimatter coexistence method\", where matter and anti-matter systems\nare prepared on two parallel ${\\bf R}^4$-sheets in five-dimensional Euclidean\nspace-time. We put a matter system $M$ with a chemical potential $\\mu \\in {\\bf\nC}$ on a ${\\bf R}^4$-sheet, and also put an anti-matter system $\\bar M$ with\n$-\\mu^*$ on the other ${\\bf R}^4$-sheet shifted in the fifth direction. Between\nthe gauge variables $U_\\nu \\equiv e^{iagA_\\nu}$ in $M$ and $\\tilde U_\\nu \\equiv\ne^{iag \\tilde A_\\nu}$ in $\\bar M$, we introduce a correlation term with a real\nparameter $\\lambda$. In one limit of $\\lambda \\rightarrow \\infty$, a strong\nconstraint $\\tilde U_\\nu(x)=U_\\nu(x)$ is realized, and therefore the total\nfermionic determinant becomes real and non-negative, due to the cancellation of\nthe phase factors in $M$ and $\\bar M$, although this system resembles QCD with\nan isospin chemical potential. In another limit of $\\lambda \\rightarrow 0$,\nthis system goes to two separated ordinary QCD systems with the chemical\npotential of $\\mu$ and $-\\mu^*$. For a given finite-volume lattice, if one\ntakes an enough large value of $\\lambda$, $\\tilde U_\\nu(x) \\simeq U_\\nu(x)$ is\nrealized and phase cancellation approximately occurs between two fermionic\ndeterminants in $M$ and $\\bar M$, which suppresses the sign problem and is\nexpected to make the lattice calculation possible. For the obtained gauge\nconfigurations of the coexistence system, matter-side quantities are evaluated\nthrough their measurement only for the matter part $M$. The physical quantities\nin finite density QCD are expected to be estimated by the calculations with\ngradually decreasing $\\lambda$ and the extrapolation to $\\lambda=0$. We also\nconsider more sophisticated improvement of this method using an irrelevant-type\ncorrelation."
    },
    {
        "anchor": "Heavy Quark Physics and Lattice QCD: I review recent progress made on heavy quark physics on the lattice.",
        "positive": "Casimir effect for lattice fermions: We propose a definition of the Casimir energy for free lattice fermions. From\nthis definition, we study the Casimir effects for the massless or massive naive\nfermion, Wilson fermion, and (M\\\"obius) domain-wall fermion in $1+1$\ndimensional spacetime with the spatial periodic or antiperiodic boundary\ncondition. For the naive fermion, we find an oscillatory behavior of the\nCasimir energy, which is caused by the difference between odd and even lattice\nsizes. For the Wilson fermion, in the small lattice size of $N \\geq 3$, the\nCasimir energy agrees very well with that of the continuum theory, which\nsuggests that we can control the discretization artifacts for the Casimir\neffect measured in lattice simulations. We also investigate the dependence on\nthe parameters tunable in M\\\"obius domain-wall fermions. Our findings will be\nobserved both in condensed matter systems and in lattice simulations with a\nsmall size."
    },
    {
        "anchor": "Monte Carlo study of real time dynamics: Monte Carlo studies involving real time dynamics are severely restricted by\nthe sign problem that emerges from highly oscillatory phase of the path\nintegral. In this letter, we present a new method to compute real time\nquantities on the lattice using the Schwinger-Keldysh formalism via Monte Carlo\nsimulations. The key idea is to deform the path integration domain to a complex\nmanifold where the phase oscillations are mild and the sign problem is\nmanageable. We use the previously introduced \"contraction algorithm\" to create\na Markov chain on this alternative manifold. We substantiate our approach by\nanalyzing the quantum mechanical anharmonic oscillator. Our results are in\nagreement with the exact ones obtained by diagonalization of the Hamiltonian.\nThe method we introduce is generic and in principle applicable to quantum field\ntheory albeit very slow. We discuss some possible improvements that should\nspeed up the algorithm.",
        "positive": "A new dual representation for staggered lattice QCD: We propose a new strategy to evaluate the partition function of lattice QCD\nwith Wilson gauge action coupled to staggered fermions, based on a strong\ncoupling expansion in the inverse bare gauge coupling $\\beta= 2N/g^{2}$. Our\nmethod makes use of the recently developed formalism to evaluate the ${\\rm\nSU}(N)$ $1-$link integrals and consists in an exact rewriting of the partition\nfunction in terms of a set of additional dual degrees of freedom which we call\n\"Decoupling Operator Indices\" (DOI). The method is not limited to any\nparticular number of dimensions or gauge group ${\\rm U}(N)$, ${\\rm SU}(N)$. In\nterms of the DOI the system takes the form of a Tensor Network which can be\nsimulated using Worm-like algorithms. Higher order $\\beta$-corrections to\nstrong coupling lattice QCD can be, in principle, systematically evaluated,\nhelping to answer the question whether the finite density sign problem remains\nmild when plaquette contributions are included. Issues related to the\ncomplexity of the description and strategies for the stochastic evaluation of\nthe partition function are discussed."
    },
    {
        "anchor": "Chiral transition and monopole percolation in lattice scalar QED with\n  quenched fermions: We study the interplay between topological observables and chiral and Higgs\ntransitions in lattice scalar QED with quenched fermions. Emphasis is put on\nthe chiral transition line and magnetic monopole percolation at strong gauge\ncoupling. We confirm that at infinite gauge coupling the chiral transition is\ndescribed by mean field exponents. We find a rich and complicated behaviour at\nthe endpoint of the Higgs transition line which hampers a satisfactory analysis\nof the chiral transition. We study in detail an intermediate coupling, where\nthe data are consistent both with a trivial chiral transition clearly separated\nfrom monopole percolation and with a chiral transition coincident with monopole\npercolation, and characterized by the same critical exponent $\\nu \\simeq 0.65$.\nWe discuss the relevance (or lack thereof) of these quenched results to our\nunderstanding of the \\chupiv\\ model. We comment on the interplay of magnetic\nmonopoles and fermion dynamics in more general contexts.",
        "positive": "QED$_3$ with Dynamical Fermions in an External Magnetic Field: In this paper, we present results of numerical lattice simulations of\ntwo-flavor QED in three space-time dimensions. First, we provide evidence that\nchiral symmetry is spontaneously broken in the chiral and continuum limit. Next\nwe discuss the role of an external magnetic field $B$ on the dynamically\ngenerated fermion mass. We investigate the $B$-dependence of the condensate\nthrough calculations with dynamical fermions using the non-compact formulation\nof the gauge field, and compare the results with those of a comparable study\nusing the quenched approximation."
    },
    {
        "anchor": "Machine Learning and Variational Algorithms for Lattice Field Theory: In lattice quantum field theory studies, parameters defining the lattice\ntheory must be tuned toward criticality to access continuum physics. Commonly\nused Markov chain Monte Carlo (MCMC) methods suffer from critical slowing down\nin this limit, restricting the precision of continuum extrapolations. Further\ndifficulties arise when measuring correlation functions of operators widely\nseparated in spacetime: for most correlation functions, an exponentially severe\nsignal-to-noise problem is encountered as the operators are taken to be widely\nseparated. This dissertation details two new techniques to address these\nissues. First, we define a novel MCMC algorithm based on generative flow-based\nmodels. Such models utilize machine learning methods to describe efficient\napproximate samplers for distributions of interest. Independently drawn\nflow-based samples are then used as proposals in an asymptotically exact\nMetropolis-Hastings Markov chain. We address incorporating symmetries of\ninterest, including translational and gauge symmetries. We secondly introduce\nan approach to \"deform\" Monte Carlo estimators based on contour deformations\napplied to the domain of the path integral. The deformed estimators associated\nwith an observable give equivalent unbiased measurements of that observable,\nbut generically have different variances. We define families of deformed\nmanifolds for lattice gauge theories and introduce methods to efficiently\noptimize the choice of manifold (the \"observifold\"), minimizing the deformed\nobservable variance. Finally, we demonstrate that flow-based MCMC can mitigate\ncritical slowing down and observifolds can exponentially reduce variance in\nproof-of-principle applications to scalar $\\phi^4$ theory and $\\mathrm{U}(1)$\nand $\\mathrm{SU}(N)$ lattice gauge theories.",
        "positive": "QCD Thermodynamics with an almost realistic quark mass spectrum: We will report on the status of a new large scale calculation of\nthermodynamic quantities in QCD with light up and down quarks corresponding to\nan almost physical light quark mass value and a heavier strange quark mass.\nThese calculations are currently being performed on the QCDOC Teraflops\ncomputers at BNL. We will present new lattice calculations of the transition\ntemperature and various susceptibilities reflecting properties of the chiral\ntransition. All these quantities are of immediate interest for heavy ion\nphenomenology."
    },
    {
        "anchor": "Dynamical fermion mass generation at a tricritical point in strongly\n  coupled U(1) lattice gauge theory: Fermion mass generation in the strongly coupled U(1) lattice gauge theory\nwith fermion and scalar fields of equal charge is investigated by means of\nnumerical simulation with dynamical fermions. Chiral symmetry of this model is\nbroken by the gauge interaction and restored by the light scalar. We present\nevidence for the existence of a particular, tricritical point of the\ncorresponding phase boundary where the continuum limit might possibly be\nconstructed. It is of interest as a model for dynamical symmetry breaking and\nmass generation due to a strong gauge interaction. In addition to the massive\nand unconfined fermion F and Goldstone boson $\\pi$, a gauge ball of mass $m_S\n\\simeq 1/2 m_F$ and some other states are found. Tricritical exponents appear\nto be non-classical.",
        "positive": "On the Weak Coupling Limit for Massive Yang-Mills: For small values of the gauge coupling constant, we compare the densities of\nthe energy of the vacuum and of the order parameter, evaluated in the lattice\nMonte Carlo simulation and in the perturbative field theory at two loop\n(Minkowski). The continuum calculation allows a very good fit of the simulation\nresults, away from the phase transition line. This confirms the conjecture that\nthe lattice provides a regularization of the (nonrenormalizable) massive\nYang-Mills and moreover it shows the physical meaning of the parameters used in\nthe simulation."
    },
    {
        "anchor": "Role of center vortices in chiral symmetry breaking in SU(3) gauge\n  theory: We study the behavior of the AsqTad quark propagator in Landau gauge on SU(3)\nYang-Mills gauge configurations under the removal of center vortices. In SU(2)\ngauge theory, center vortices have been observed to generate chiral symmetry\nbreaking and dominate the infrared behavior of the quark propagator. In\ncontrast, we report a weak dependence on the vortex content of the gauge\nconfigurations, including the survival of dynamical mass generation on\nconfigurations with vanishing string tension.",
        "positive": "First evidence for Casimir scaling in G(2) lattice gauge theory: Potentials between static quarks and antiquarks from a few lowest\nrepresentations were evaluated in numerical simulations of 4-dimensional pure\nG$_2$ lattice gauge theory at various couplings. The obtained potentials are\nlinearly rising at intermediate distances and their string tensions exhibit\n(approximate) Casimir scaling. This result is in accordance with a model of the\nvacuum of non-Abelian gauge theories with a domain structure, in which the\n(color) magnetic flux randomly fluctuates within a domain, but the total flux\nin each domain is quantized in units of the gauge group center."
    },
    {
        "anchor": "Instabilities and Non-Reversibility of Molecular Dynamics Trajectories: The theoretical justification of the Hybrid Monte Carlo algorithm depends\nupon the molecular dynamics trajectories within it being exactly reversible. If\ncomputations were carried out with exact arithmetic then it would be easy to\nensure such reversibility, but the use of approximate floating point arithmetic\ninevitably introduces violations of reversibility. In the absence of evidence\nto the contrary, we are usually prepared to accept that such rounding errors\ncan be made small enough to be innocuous, but in certain circumstances they are\nexponentially amplified and lead to blatantly erroneous results. We show that\nthere are two types of instability of the molecular dynamics trajectories which\nlead to this behavior, instabilities due to insufficiently accurate numerical\nintegration of Hamilton's equations, and intrinsic chaos in the underlying\ncontinuous fictitious time equations of motion themselves. We analyze the\nformer for free field theory, and show that it is essentially a finite volume\neffect. For the latter we propose a hypothesis as to how the Liapunov exponent\ndescribing the chaotic behavior of the fictitious time equations of motion for\nan asymptotically free quantum field theory behaves as the system is taken to\nits continuum limit, and explain why this means that instabilities in molecular\ndynamics trajectories are not a significant problem for Hybrid Monte Carlo\ncomputations. We present data for pure $SU(3)$ gauge theory and for QCD with\ndynamical fermions on small lattices to illustrate and confirm some of our\nresults.",
        "positive": "Non-perturbative generation of elementary fermion masses: a numerical\n  study: In this talk we present a numerical lattice study of an SU(3) gauge model\nwhere an SU(2) doublet of non-Abelian strongly interacting fermions is coupled\nto a complex scalar field doublet via a Yukawa and a Wilson-like term. The\nmodel enjoys an exact symmetry, acting on all fields, which prevents UV power\ndivergent fermion mass corrections, despite the presence of these two chiral\nbreaking operators in the Lagrangian. In the phase where the scalar potential\nis non-degenerate and fermions are massless, the bare Yukawa coupling can be\nset at a critical value at which chiral fermion transformations become\nsymmetries of the theory. Numerical simulations in the Nambu-Goldstone phase of\nthe critical theory, for which the renormalized Yukawa coupling by construction\nvanishes, give evidence for non-perturbative generation of a UV finite fermion\nmass term in the effective action."
    },
    {
        "anchor": "Multi-Grid Monte Carlo III. Two-Dimensional O(4)-Symmetric Nonlinear\n  $\u03c3$-Model: We study the dynamic critical behavior of the multi-grid Monte Carlo (MGMC)\nalgorithm with piecewise-constant interpolation applied to the two-dimensional\nO(4)-symmetric nonlinear $\\sigma$-model [= SU(2) principal chiral model], on\nlattices up to $256 \\times 256$. We find a dynamic critical exponent\n$z_{int,{\\cal M}^2} = 0.60 \\pm 0.07$ for the W-cycle and $z_{int,{\\cal M}^2} =\n1.13 \\pm 0.11$ for the V-cycle, compared to $z_{int,{\\cal M}^2} = 2.0 \\pm 0.15$\nfor the single-site heat-bath algorithm (subjective 68% confidence intervals).\nThus, for this asymptotically free model, critical slowing-down is greatly\nreduced compared to local algorithms, but not completely eliminated. For a $256\n\\times 256$ lattice, W-cycle MGMC is about 35 times as efficient as a\nsingle-site heat-bath algorithm.",
        "positive": "Deconfining Chiral Transition in QCD on the Lattice: The deconfining chiral transition in finite-temperature QCD is studied on the\nlattice using Wilson quarks. After discussing the nature of chiral limit with\nWilson quarks, we first study the case of two degenerate quarks $N_F=2$, and\nfind that the transition is smooth in the chiral limit on both $N_t=4$ and 6\nlattices. For $N_F=3$, on the other hand, clear two state signals are observed\nfor $m_q \\simm{<} 140$ MeV on $\\nt=4$ lattices. For a more realistic case of\n$N_F=2+1$, i.e.\\ two degenerate u and d-quarks and a heavier s-quark, we study\nthe cases $m_s \\simeq 150$ and 400 MeV with $m_u = m_d \\simeq 0$: In contrast\nto a previous result with staggered quarks, clear two state signals are\nobserved for both cases, suggesting a first order QCD phase transition in the\nreal world."
    },
    {
        "anchor": "Spectroscopy of doubly-charmed baryons from lattice QCD: We present the ground and excited state spectra of doubly charmed baryons\nfrom lattice QCD with dynamical quark fields. Calculations are performed on\nanisotropic lattices of size 16^3 X 128, with inverse spacing in temporal\ndirection 1/a_t = 5.67(4) GeV and with a pion mass of about 390 MeV. A large\nset of baryonic operators that respect the symmetries of the lattice yet which\nretain a memory of their continuum analogues are used. These operators\ntransform as irreducible representations of SU(3) symmetry for flavor, SU(4)\nsymmetry for Dirac spins of quarks and O(3) for spatial symmetry. The\ndistillation method is utilized to generate baryon correlation functions which\nare analysed using the variational fitting method to extract excited states.\nThe lattice spectra obtained have baryonic states with well-defined total spins\nup to 7/2 and the pattern of low lying states does not support the diquark\npicture for doubly charmed baryons. On the contrary the calculated spectra are\nremarkably similar to the expectations from models with an SU(6)X O(3)\nsymmetry. Various spin dependent energy splittings between the extracted states\nare also evaluated.",
        "positive": "Finite temperature QCD: progress and outstanding problems: I review recent progress in numerical simulations of finite temperature\nquantum chromodynamics and discuss the status of some outstanding problems.\nIncluded is (1) a discussion of recent results determining the temperature of\nthe ``phase transition'' in full QCD, (2) a scaling analysis of the Polyakov\nloop variable, leading to the determination of a constituent quark free energy,\n(3) studies of critical behavior near the phase transition in two-flavor QCD,\n(4) a discussion of problems and new results in thermodynamic simulations with\nWilson fermions, (5) recent results in pure gauge theory with a mixed\nfundamental/adjoint action, and (6) the nonperturbative determination of the\nequation of state with dynamical fermions included. Finally I mention briefly\nnew developments in efforts to construct a phenomenology of deconfinement and\nchiral symmetry restoration, namely (7) the dual superconducting model and (8)\nthe instanton model."
    },
    {
        "anchor": "Fermionic quantum field theories as probabilistic cellular automata: A class of fermionic quantum field theories with interactions is shown to be\nequivalent to probabilistic cellular automata, namely cellular automata with a\nprobability distribution for the initial states. Probabilistic cellular\nautomata on a one-dimensional lattice are equivalent to two - dimensional\nquantum field theories for fermions. They can be viewed as generalized Ising\nmodels on a square lattice and therefore as classical statistical systems. As\nquantum field theories they are quantum systems. Thus quantum mechanics emerges\nfrom classical statistics. As an explicit example for an interacting fermionic\nquantum field theory we describe a type of discretized Thirring model as a\ncellular automaton. The updating rule of the automaton is encoded in the step\nevolution operator that can be expressed in terms of fermionic annihilation and\ncreation operators. The complex structure of quantum mechanics is associated to\nparticle -- hole transformations. The naive continuum limit exhibits Lorentz\nsymmetry. We exploit the equivalence to quantum field theory in order to show\nhow quantum concepts as wave functions, density matrix, non-commuting operators\nfor observables and similarity transformations are convenient and useful\nconcepts for the description of probabilistic cellular automata.",
        "positive": "Examining the Low Energy Dynamics of Walking Gauge Theory: We report on an investigation into the low energy dynamics of walking gauge\ntheory. Taking $SU(3)$ Yang Mills with eight flavors of fundamental fermions as\nan example, we discuss the light flavor singlet scalar appearing in the\nspectrum and its implications for low energy physics. We compute the maximal\nisospin $\\pi\\pi$ scattering length at the lightest quark masses yet\ninvestigated for the eight flavor theory. The validity of chiral perturbation\ntheory is assessed, and we discuss motivations for a more extensive effective\nfield theory analysis to be carried out in future work."
    },
    {
        "anchor": "A new lattice gauge action without scaling artifacts: I describe a new way of constructing a gauge action that eliminates scaling\nartifacts, by writing the continuum formalism in terms of \"gauge links\"\n(Schwinger line integrals) and using the optimal SLAC representation of the\nlattice derivative. Computational performance can be maintained by implementing\nthe action as a \"stochastic\" operator, as has been recently implemented in the\nMILC code for the optimal D-slash operator and the antialiasing filter.",
        "positive": "Banks-Casher-type relations for complex Dirac spectra: For theories with a sign problem there is no analog of the Banks-Casher\nrelation. This is true in particular for QCD at nonzero quark chemical\npotential. However, for QCD-like theories without a sign problem the\nBanks-Casher relation can be extended to the case of complex Dirac eigenvalues.\nWe derive such extensions for the zero-temperature, high-density limits of\ntwo-color QCD, QCD at nonzero isospin chemical potential, and adjoint QCD. In\nall three cases the density of the complex Dirac eigenvalues at the origin is\nproportional to the BCS gap squared."
    },
    {
        "anchor": "One-flavor algorithm for Wilson and domain-wall fermions: We construct positive-definite pseudofermion actions for one fermion flavor\nin lattice field theory, for Wilson and domain-wall fermions respectively. The\npositive definiteness of these actions ensures that they can be simulated with\nthe Hybrid Monte Carlo (HMC) method. For lattice QCD with optimal domain-wall\nquarks, we compare the efficiency of HMC simulations of 2-flavor and\n(1+1)-flavor, and find that the efficiency ratio is about 3:2.",
        "positive": "Delta expansion at low temperatures: In the low temperature phase of the square Ising model, we describe the\ninverse temperature beta as the function of a squared mass M and study the\ncritical behavior of beta(M) via the large M expansion. Using the\ndelta-expansion by which the large mass expansion is transformed into a series\nexhibiting expected scaling behavior, we perform the estimation of the critical\ninverse temperature beta_{c} with the help of linear differential equation to\nbe satisfied by ansatz of beta(M) near the critical point M=0. To improve the\nestimation, the leading correction exponent nu is independently estimated from\nbeta^{(2)}/beta^{(1)} and is used in the estimation of beta_{c}, giving rise to\nremarkable accuracy improvement."
    },
    {
        "anchor": "Beyond Complex Langevin Equations: a Progress Report: After a short review of one of proposals to avoid complex stochastic\nprocesses in Complex Langevin studies, the recent progress in the former is\nreported. In particular, the new developments allow now to construct positive\nand normalizable representations for gaussian quantum mechanical, as well as\nfield theoretical, path integrals directly in the Minkowski time. A relation to\nthe idea of thimbles is also discussed.",
        "positive": "Radial Correlations between two quarks: In nuclear many-body problems the short-range correlation between two\nnucleons is well described by the corresponding correlation in the {two}-body\nproblem. Therefore, as a first step in any attempt at an analogous description\nof many-quark systems, it is necessary to know the two-quark correlation. With\nthis in mind, we study the light quark distribution in a heavy-light meson with\na static heavy quark. The charge and matter radial distributions of these\nheavy-light mesons are measured on a lattice with a light quark mass about that\nof the strange quark. Both distributions can be well fitted upto r approx 0.7\nfm with the exponential form w_i^2(r), where w_i(r)=A exp(-r/r_i). For the\ncharge(c) and matter(m) distributions r_c approx 0.32(2) fm and r_m \\approx\n0.24(2) fm. We also discuss the normalisation of the total charge (defined to\nbe unity in the continuum limit) and matter integrated over all space, finding\n1.30(5) and 0.4(1) respectively for a lattice spacing approx 0.17 fm."
    },
    {
        "anchor": "Lattice Chiral Gauge Theories in a Renormalizable Gauge: The lattice formulation of gauge theories in a renormalizable gauge is\ndiscussed. The formulation invokes a new phase diagram, and it may allow for a\nlattice definition of Chiral Gauge Theories.",
        "positive": "Low-lying baryon masses using $N_f=2$ twisted mass clover-improved\n  fermions directly at the physical point: The masses of the low-lying baryons are evaluated using an ensemble with two\ndegenerate light twisted mass clover-improved quarks with mass tuned to\nreproduce the physical pion mass. The Iwasaki improved gluonic action is\nemployed. The coupling constant value corresponds to a lattice spacing of\n$a=0.0938(3)(2)$ fm, determined from the nucleon mass. We find that the clover\nterm supresses isospin symmetry breaking as compared to our previous results\nusing $N_f=2+1+1$ twisted mass fermions. The masses of the hyperons and charmed\nbaryons evaluated using this ensemble are in agreement with the experimental\nvalues. We provide predictions for the mass of the doubly charmed $\\Xi_{cc}^*$,\nas well as of the doubly and triply charmed $\\Omega$s that have not yet been\ndetermined experimentally."
    },
    {
        "anchor": "Partially quenched chiral perturbation theory for N=1 supersymmetric\n  Yang-Mills theory: Adding a gluino mass term to N=1 supersymmetric Yang-Mills theory breaks\nsupersymmetry softly. In order to approach the supersymmetric continuum limit\nin numerical simulations with the Wilson action, the bare gluino mass has to be\ntuned to the limit of vanishing renormalised gluino mass. This can be done\nefficiently by means of the mass of the adjoint pion, which is, however, an\nunphysical particle. We discuss how the adjoint pion can be defined in the\nframework of partially quenched chiral perturbation theory. A relation between\nits mass and the mass of the gluino, analogous to the Gell-Mann-Oakes-Renner\nrelation of QCD, can be derived.",
        "positive": "Chiral Loop Effects in the Quenched Scalar Isovector Propagator: The scalar isovector meson propagator is studied in quenched QCD. For the\nlightest quark masses used, this propagator is dominated by a quenched chiral\nloop effect associated with the $\\eta'$-$\\pi$ two-meson intermediate state.\nBoth the time dependence and the pion mass dependence of the effect are\nwell-described by quenched chiral perturbation theory."
    },
    {
        "anchor": "Power Counting Regime of Chiral Effective Field Theory and Beyond: Chiral effective field theory complements numerical simulations of quantum\nchromodynamics (QCD) on a space-time lattice. It provides a model-independent\nformalism for connecting lattice simulation results at finite volume and a\nvariety of quark masses to the physical world. The asymptotic nature of the\nchiral expansion places the focus on the first few terms of the expansion.\nThus, knowledge of the power-counting regime (PCR) of chiral effective field\ntheory, where higher-order terms of the expansion may be regarded as\nnegligible, is as important as knowledge of the expansion itself. Through the\nconsideration of a variety of renormalization schemes and associated\nparameters, techniques to identify the PCR where results are independent of the\nrenormalization scheme are established. The nucleon mass is considered as a\nbenchmark for illustrating this general approach. Because the PCR is small, the\nnumerical simulation results are also examined to search for the possible\npresence of an intrinsic scale which may be used in a nonperturbative manner to\ndescribe lattice simulation results outside of the PCR. Positive results that\nimprove on the current optimistic application of chiral perturbation theory\nbeyond the PCR are reported.",
        "positive": "Non-perturbative BRST invariance and what it might be good for: We construct a local, gauge-fixed, lattice Yang-Mills theory with an exact\nBRST invariance, and with the same perturbative expansion as the standard\nYang-Mills theory. The ghost sector, and some of its BRST transformation rules,\nare modified to get around Neuberger's theorem. A special term is introduced in\nthe action to regularize the Gribov horizons, and the limit where the regulator\nis removed is discussed. We conclude with a few comments on what might be the\nphysical significance of this theory. We speculate that there may exist new\nstrong-interaction phases apart from the anticipated confinement phase."
    },
    {
        "anchor": "Ultralocality on the lattice: It is shown that the nonlocal Dirac operator yielded by a lattice model that\npreserves chiral symmetry and uniqueness of fields, approaches to an ultralocal\nand invariant under translations operator when the size of the lattice tends to\nzero.",
        "positive": "The chiral condensate of $N_f=2+1$ QCD from the spectrum of the\n  staggered Dirac operator: We compute the chiral condensate of $2+1$ QCD from the mode number of the\nstaggered Dirac operator, performing controlled extrapolations to both the\ncontinuum and the chiral limit. We consider also alternative strategies, based\non the quark mass dependence of the topological susceptibility and of the pion\nmass, and obtain consistent results within errors. Results are also consistent\nwith phenomenological expectations and with previous numerical determinations\nobtained with different lattice discretizations."
    },
    {
        "anchor": "A Fermion Doublet With Chiral Gauge Interaction On A Lattice: We present a new staggered discretization of the Dirac operator. Doubling\ngives only a doublet of Dirac fermions which we propose to interpret as a\nphysical (lepton or quark) doublet. If coupled with gauge fields, an\n$(1+\\gamma^5)$ chiral interaction appears in a natural way. We define a\ngeneralization for curved background which does not require tetrad variables.\nThe approach suggests a natural explanation for the three fermion families.",
        "positive": "Construction of energy-independent potentials above inelastic thresholds\n  in quantum field theories: We construct energy independent but non-local potentials above inelastic\nthresholds, in terms of Nambu-Bethe-Salpeter wave functions defined in quantum\nfield theories such as QCD. As an explicit example, we consider NN --> NN + n\npi scattering processes for n=0,1,2,.... We show an existence of\nenergy-independent coupled channel potentials with a non-relativistic\napproximation, where momenta of all particles are small compared with their own\nmasses. In the case of two-body inelastic scatterings such as Lambda Lambda -->\nLambda Lambda, N Xi, Sigma Sigma, on the other hand, we show that\nenergy-independent potentials can be constructed without relying on\nnon-relativistic approximations. We also propose a method to extract these\npotentials using time-dependence of general correlation functions."
    },
    {
        "anchor": "Reliability of Taylor expansions in QCD: We investigate the reliability of the Taylor expansion method in QCD with\nisospin chemical potentials using lattice simulations. By comparing the\nexpansion of the number density to direct results, the range of validity of the\nleading- and next-to-leading order expansions is determined. We also elaborate\non the convergence properties of the Taylor series by comparing the leading\nestimate for the radius of convergence to the position of the nearest\nsingularity, i.e. the onset of pion condensation. Our results provide a handle\nfor quantifying the uncertainties of Taylor expansions in baryon chemical\npotentials.",
        "positive": "Finite-element quantum field theory: An alternative approach to lattice gauge theory has been under development\nfor the past decade. It is based on discretizing the operator Heisenberg\nequations of motion in such a way as to preserve the canonical commutation\nrelations at each lattice site. It is now known how to formulate a non-Abelian\ngauge theory within this framework. The formulation appears to be free of\nfermion doubling. Since the theory is unitary, a time-development operator\n(Hamiltonian) can be constructed."
    },
    {
        "anchor": "Center vortex model for the infrared sector of SU(4) Yang-Mills theory:\n  String tensions and deconfinement transition: A random vortex world-surface model for the infrared sector of SU(4)\nYang-Mills theory is constructed, focusing on the confinement properties and\nthe behavior at the deconfinement phase transition. Although the corresponding\ndata from lattice Yang-Mills theory can be reproduced, the model requires a\nmore complex action and considerably more tuning than the SU(2) and SU(3) cases\nstudied previously. Its predictive capabilities are accordingly reduced. This\nbehavior has a definite physical origin, which is elucidated in detail in the\npresent work. As the number of colors is raised in Yang-Mills theory, the\ncorresponding infrared effective vortex description cannot indefinitely\ncontinue to rely on dynamics determined purely by vortex world-surface\ncharacteristics; additional color structures present on the vortices begin to\nplay a role. As evidenced by the modeling effort reported here, definite\nsignatures of this behavior appear in the case of four colors.",
        "positive": "Testing OPE for ghosts, gluons and $\u03b1_s$: We present here our results on extracting Wilson coefficients from different\nquantities such as ghost and gluon propagators which are calculated by means of\nLattice QCD. The results confirm the validity of our method for the calculation\nof the strong coupling constant as well as allow to estimate the range of\nmomenta where OPE is applicable."
    },
    {
        "anchor": "Exact Correlators in the 't Hooft Limit of the Principal Chiral Model: The properties of (N X N)-matrix-valued-field theories, in the limit N goes\nto infinity, are harder to obtain than those for isovector-valued field\ntheories. This is because we know less about the sum of planar diagrams than\nthe sum of bubble/linear diagrams. Combining the 1/N-expansion with the axioms\nfor form factors, exact form factors can be found for the integrable field\ntheory of an SU(N)-valued field in 1+1 dimensions. These form factors can be\nused to find the vacuum expectation value of the product of two field\noperators. We briefly mention how the results can be applied to 2+1 dimensional\ngauge theories.",
        "positive": "Constant contribution in meson correlators at finite temperature: We discuss a constant contribution to meson correlators at finite\ntemperature. In the deconfinement phase of QCD, a colored single quark state is\nallowed as a finite energy state, which yields to a contribution of wraparound\nquark propagation to temporal meson correlators. We investigate the effects in\nthe free quark case and quenched QCD at finite temperature. The ``scattering''\ncontribution causes a constant mode in meson correlators with zero spatial\nmomentum and degenerate quark masses, which can dominate the correlators in the\nregion of large imaginary times. In the free spectral function, the\ncontribution yields a term proportional to $\\omega\\delta(\\omega)$. Therefore\nthis contribution is related to transport phenomena in the quark gluon plasma.\nIt is possible to distinguish the constant contribution from the other part\nusing several analysis methods proposed in this paper. As a result of the\nanalyses, we find that drastic changes in charmonium correlators for $\\chi_c$\nstates just above the deconfinement transition are due to the constant\ncontribution. The other differences in the $\\chi_c$ states are small. It may\nindicate the survival of $\\chi_c$ states after the deconfinement transition\nuntil, at least, $1.4T_c$."
    },
    {
        "anchor": "The Vector Meson Mass in Chiral Effective Field Theory: A brief overview of Quantum Chromodynamics (QCD) as a non-Abelian gauge field\ntheory, including symmetries and formalism of interest, will precede a focused\ndiscussion on the use of an Effective Field Theory (EFT) as a low energy\nperturbative expansion technique. Regularization schemes involved in Chiral\nPerturbation Theory (\\c{hi}PT) will be reviewed and compared with EFT. Lattices\nwill be discussed as a useful procedure for studying large mass particles. An\nEffective Field Theory will be formulated, and the self energy of the \\r{ho}\nmeson for a Finite-Range Regulated (FRR) theory will be calculated. This will\nbe performed in both full QCD and the simpler quenched approximation (QQCD).\nFinite-volume artefacts, due to the finite box size on the lattice, will be\nquantified. Currently known lattice results will be used to calculate the\n\\r{ho} meson mass, and the possibility of unquenching will be explored. The aim\nof the research was to determine whether a stable unquenching procedure for the\n\\r{ho} meson could be discovered. The results from the original research\nindicate that there is no such procedure because the \\r{ho} mesons are\nunstable. Unless additional data involving lighter quark masses is available,\nan element of modelling is needed for successful unquenching.",
        "positive": "Light quarks with twisted mass fermions: We investigate Wilson twisted mass fermions in the quenched approximation\nusing different definitions of the critical bare quark mass m_c to realize\nmaximal twist and, correspondingly, automatic O(a) improvement for physical\nobservables. A particular definition of m_c is given by extrapolating the value\nof m_c obtained from the PCAC relation at non-vanishing bare twisted quark mass\nmu to mu=0. Employing this improved definition of the critical mass the Wilson\ntwisted mass formulation provides the possibility to perform reliable\nsimulations down to very small quark masses with correspondingly small pion\nmasses of m_pi \\simeq 250 MeV, while keeping the cutoff effects of O(a^2) under\ncontrol."
    },
    {
        "anchor": "Vortices and confinement at weak coupling: We discuss the physical picture of thick vortices as the mechanism\nresponsible for confinement at arbitrarily weak coupling in SU(2) gauge theory.\nBy introducing appropriate variables on the lattice we distinguish between\nthin, thick and `hybrid' vortices, the latter involving Z(2) monopole loop\nboundaries. We present numerical lattice simulation results that demonstrate\nthat the full SU(2) string tension at weak coupling arises from the presence of\nvortices linked to the Wilson loop. Conversely, excluding linked vortices\neliminates the confining potential. The numerical results are stable under\nalternate choice of lattice action as well as a smoothing procedure which\nremoves short distance fluctuations while preserving long distance physics.",
        "positive": "Hadronic physics from a Wilson fermion mixed-action approach: Charm\n  quark mass and $D_{(s)}$ meson decay constants: We present our first set of results for charm physics, using the mixed-action\nsetup introduced in a companion paper. Maximally twisted Wilson valence\nfermions are used on a sea of non-perturbatively $O(a)$-improved Wilson\nfermions, made up by CLS $N_{\\mathrm{\\scriptstyle f}}=2+1$ ensembles. Our\ncharm-sector observables are free from $O(am_c)$ discretisation effects,\nwithout need of tuning any improvement coefficient, and show continuum-limit\nscaling properties consistent with leading cutoff effects of $O(a^2)$. We\nconsider a subset of CLS ensembles -- including four values of the lattice\nspacing and pion masses down to 200 MeV -- allowing to take the continuum limit\nand extrapolate to the physical pion mass. A number of techniques are\nincorporated in the analysis in order to estimate the systematic uncertainties\nof our results for the charm quark mass and the $D_{(s)}$-meson decay\nconstants. This first study of observables in the charm sector, where the\nemphasis has been on the control of the methodology, demonstrates the potential\nof our setup to achieve high-precision results."
    },
    {
        "anchor": "Vortex Loops In The 3-d XY Model: We study the properties of vortex loops in the 3-d XY model. We find that the\nphase transition in this model is driven by the condensation of short loops\ninto percolating loops. Paper comes as a uuencoded compressed tar-file,\ncontaining the complete PostScript file. Total file approx. 220 Kb.",
        "positive": "Sizes of Lightest Glueballs in SU(3) Lattice Gauge Theory: Standard Monte Carlo simulations have been performed on improved lattices to\nmeasure the wave functions and sizes of the scalar and tensor glueballs at four\nlattice spacings in the range $a= 0.05 - 0.145$ fm. Systematic errors from\ndiscretization and finite volume are studied. Our results in the continuum\nlimit show that the size of the tensor state is approximately two times as\nlarge as that of the scalar glueball."
    },
    {
        "anchor": "Couplings of hybrid operators to ground and excited states of bottomonia: We analyze the overlap of local color-octet meson operators with the\n$\\Upsilon$ and the $\\eta_b$ and their low-lying excited states, especially the\nfirst radial excitations. Our analysis is based on NRQCD and includes all terms\nup to order $v^4$. We use a variety of source and sink operators as a basis for\nthe variational method, which enables us to clearly separate the mass\neigenstates and hence to extract the desired amplitudes. The results show the\nusefulness of the variational method for determining couplings to excited\nhadronic states.",
        "positive": "Heavy-Baryon Spectroscopy from Lattice QCD: We use a four-dimensional lattice calculation of the full-QCD (quantum\nchromodynamics, the non-abliean gauge theory of the strong interactions of\nquarks and gluons) path integrals needed to determine the masses of the charmed\nand bottom baryons. In the charm sector, our results are in good agreement with\nexperiment within our systematics, except for the spin-1/2 $\\Xi_{cc}$, for\nwhich we found the isospin-averaged mass to be $\\Xi_{cc}$ to be\n$3665\\pm17\\pm14^{+0}_{-78}$ MeV. We predict the mass of the (isospin-averaged)\nspin-1/2 $\\Omega_{cc}$ to be $3763\\pm19\\pm26^{+13}_{-79}$ {MeV}. In the bottom\nsector, our results are also in agreement with experimental observations and\nother lattice calculations within our statistical and systematic errors. In\nparticular, we find the mass of the $\\Omega_b$ to be consistent with the recent\nCDF measurement. We also predict the mass for the as yet unobserved\n$\\Xi^\\prime_b$ to be 5955(27) MeV."
    },
    {
        "anchor": "Complex spacing ratios of the non-Hermitian Dirac operator in\n  universality classes AI$^\\dagger$ and AII$^\\dagger$: We consider non-Hermitian Dirac operators in QCD-like theories coupled to a\nchiral U(1) potential or an imaginary chiral chemical potential. We show that\nin the continuum they fall into the recently discovered universality classes\nAI$^\\dagger$ or AII$^\\dagger$ of random matrix theory if the fermions transform\nin pseudoreal or real representations of the gauge group, respectively. For\nstaggered fermions on the lattice this correspondence is reversed. We verify\nour predictions by computing spacing ratios of complex eigenvalues, whose\ndistribution is universal without the need for unfolding.",
        "positive": "Low-Temperature Series for the Correlation Length in $d=3$ Ising Model: We extend low-temperature series for the second moment of the correlation\nfunction in $d=3$ simple-cubic Ising model from $u^{15}$ to $u^{26}$ using\nfinite-lattice method, and combining with the series for the susceptibility we\nobtain the low-temperature series for the second-moment correlation length to\n$u^{23}$. An analysis of the obtained series by inhomogeneous differential\napproximants gives critical exponents $ 2\\nu^{\\prime} + \\gamma^{\\prime} \\approx\n2.55 $ and $ 2\\nu^{\\prime} \\approx 1.27 $."
    },
    {
        "anchor": "Large statistics study of the topological charge distribution in the\n  SU(3) gauge theory: We present preliminary results for a high statistics study of the topological\ncharge distribution in the SU(3) Yang-Mills theory obtained by using the\ndefinition of the charge suggested by Neuberger fermions. We find statistical\nevidence for deviations from a gaussian distribution. The large statistics\nrequired has been obtained by using PCs of the INFN-GRID.",
        "positive": "QCD $\u03b2$ Function with Two Flavors of Dynamical Wilson Fermions: We test the asymptotic scaling behavior of state-of-the-art simulations of\nQCD with two flavors of light Wilson fermions. This is done by matching $\\pi$\nand $\\rho$ masses on lattices of size $16^3\\times32$ and $8^3\\times16$. We find\nthat at $\\beta=6/g^2=5.3$ matching is not possible over a range extending down\nto $\\beta=3.5$. The large lattice data at $\\beta=5.5$ matches the small lattice\nvalues at $\\beta=4.9(1)$ leading to a shift $\\Delta\\beta=0.6(1)$, considerably\nlarger than the perturbative prediction of $0.45$. In both cases we conclude\nthat the simulations are very far from the asymptotic scaling region."
    },
    {
        "anchor": "Improving the Lattice QCD Hamiltonian: Improvement of the Hamiltonian in lattice gauge theory is considered. We give\nexplicit expressions for classical improvement and discuss also quantum\ncorrections.",
        "positive": "Fits of finite-volume smeared spectral densities: Motivated by recent progress in the numerical inversion of the Laplace\ntransform, we investigate applications of finite-volume smeared spectral\ndensities. These include the tuning of operator smearing, and the study of the\nfinite-volume spectrum."
    },
    {
        "anchor": "Approaching conformality with the Tensor Renormalization Group method: We discuss the Tensor Renormalization Group (TRG) method for the O(2) model\nwith a chemical potential in 1+1 dimensions with emphasis on near\ngapless/conformal situations. We emphasize the role played by the late Leo\nKadanoff in the development of this theoretical framework. We describe the\nentanglement entropy in the superfluid phase (see arXiv:1507.01471 for\ndetails). We present recent progress on optimized truncation methods.",
        "positive": "Quenched Static force from generalized Wilson loops with gradient flow: We compute the static force on the lattice in the quenched case directly\nthrough generalized Wilson loops. We modify the Wilson loop by inserting an\n$E$-field component on one of the temporal Wilson lines. However, chromo-field\ncomponents prevent us from performing the continuum limit properly, hence, we\nuse gradient flow to renormalize the field insertion. As a result, we obtain\ncontinuum results and compare them to perturbative expression to extract\n$\\Lambda_0$, and we predict the value $\\sqrt{8t_0}\n\\Lambda_{\\overline{\\textrm{MS}}}^{n_f=0} =0.629^{+22}_{-26}$. This work serves\nas preparation for similar operators with field insertions required in\nnonrelativistic effective field theories."
    },
    {
        "anchor": "Spatial and Temporal Hadron Correlators below and above the Chiral Phase\n  Transition: Hadronic correlation functions at finite temperature in QCD, with four\nflavours of dynamical quarks, have been analyzed both above and below the\nchiral symmetry restoration temperature. We have used both point and extended\nsources for spatial as well as temporal correlators. The effect of periodic\ntemporal boundary conditions for the valence quarks on the spatial meson\ncorrelators has also been investigated. All our results are consistent with the\nexistence of individual quarks at high temperatures. A measurement of the\nresidual interaction between the quarks is presented.",
        "positive": "Progress towards a lattice determination of (moments of) nucleon\n  structure functions: Using unimproved and non-perturbatively O(a) improved Wilson fermions,\nresults are given for the three lowest moments of unpolarised nucleon structure\nfunctions. Renormalisation, chiral extrapolation and the continuum limit of the\nmatrix elements are briefly discussed. The simulations are performed for both\nquenched and two flavours of unquenched fermions. No obvious sign of deviation\nfrom linearity in the chiral extrapolations are found. (This is most clearly\nseen in our quenched unimproved data, which extends to lighter quark mass.)\nPossible quenching effects also seem to be small. The lowest moment thus\nremains too large, so it seems to be necessary to reach smaller quark masses in\nnumerical simulations."
    },
    {
        "anchor": "Inside the SU(3) quark-antiquark QCD flux tube: screening versus quantum\n  widening: In lattice QCD, colour confinement manifests in flux tubes. We compute in\ndetail the quark-antiquark flux tube for pure gauge SU(3) dimension $D=3+1$ for\nquark-antiquark distances R ranging from 0.4 fm to 1.4 fm. To increase the\nsignal over noise ratio, we apply the improved multihit and extended smearing\ntechniques. We detail the gauge invariant squared components of the colour\nelectric and colour magnetic fields both in the mediator plane between the\nstatic quark and static antiquark and in the planes of the sources. We fit the\nfield densities with appropriate ansatze and we observe the screening of the\ncolour fields in all studied planes together with the quantum widening of the\nflux tube in the mediator plane. All components squared of the colour fields\nare non-vanishing and are consistent with a penetration length lambda ~ 0.22 to\n0.24 fm and an effective screening mass mu ~ 0.9 to 0.8 GeV. The quantum\nwidening of the flux tube is well fitted with a logarithmic law in R.",
        "positive": "Fluctuations, correlations and the sign problem in QCD: We study the distribution of the phase angle and the magnitude of the fermion\ndeterminant as well as its correlation with the chiral condensate and the\nbaryon number for QCD at non-zero quark chemical potential. Results are derived\nto one-loop order in Chiral Perturbation Theory (ChPT), as well as by\nanalytical and numerical calculations in QCD in one Euclidean dimension. We\nfind a qualitative change of the distribution of the phase of the fermion\ndeterminant when the quark mass enters the spectrum of the Dirac operator: it\nchanges from a periodicized Gaussian distribution to a periodicized Lorentzian\ndistribution. We also explore the possibility that some observables remain\nweakly correlated with the phase of the fermion determinant even though the\nsign problem is severe. We discuss the practical implications of our findings\non lattice simulations of QCD at non-zero baryon chemical potential."
    },
    {
        "anchor": "The Low-lying Dirac Eigenmodes from Domain Wall Fermions: We calculate the low-lying eigenvalues and eigenvectors of the hermitian\ndomain wall Dirac operator on various gauge backgrounds by Ritz minimization.\nThe mass dependence of these eigenvalues is studied to extract the physical 4\ndimensional $\\lambda$, whose spectral density is related to $<\\bar{\\psi} \\psi>$\nthrough the Banks-Casher relation, and $\\delta m$, which represents the effects\nof the residual chiral symmetry breaking in domain wall formalism on a per\neigenmode basis. The topological structure of the underlying gauge field is\nexamined by measuring the $\\Gamma_5$ matrix elements between the low-lying\neigenmodes.",
        "positive": "The D to K and D to pi semileptonic decay form factors from Lattice QCD: We present a new and very high statistics study of D and D_s semileptonic\ndecay form factors on the lattice. We work with MILC N_f=2+1 lattices and use\nthe Highly Improved Staggered Action (HISQ) for both the charm and the light\nvalence quarks. We use both scalar and vector currents to determine the form\nfactors f_0(q^2) and f_+(q^2) for a range of D and D_s form factors including\nthose for D to pi and D to K semileptonic decays. By using a phased boundary\ncondition we are able to tune accurately to q^2=0. We also compare the shape in\nq^2 to that from experiment. We show that the form factors are very insensitive\nto the spectator quark: D to K and D_s to eta_s form factors are essentially\nthe same, and the same is true for D to pi and D_s to K. This has important\nimplications when considering the corresponding B/B_s processes."
    },
    {
        "anchor": "Mean field analysis of the SO(3) lattice gauge theory at finite\n  temperature: We study the finite temperature properties of the SO(3) lattice gauge theory\nusing mean field theory. The main result is the calculation of the effective\naction at finite temperature. The form of the effective action is used to\nexplain the behaviour of the adjoint Wilson line in numerical simulations.\nNumerical simulations of the SO(3) lattice gauge theory show that the adjoint\nWilson line has a very small value at low temperatures; at high temperatures,\nmetastable states are observed in which the adjoint Wilson line takes positive\nor negative values. The effective action is able to explain the origin of these\nmetastable states. A comparison of the effective actions of the SU(2) and the\nSO(3) lattice gauge theories explains their different behaviour at high\ntemperatures. The mean field theory also predicts a finite temperature phase\ntransition in the SO(3) lattice gauge theory.",
        "positive": "Twisted reduction in large N QCD with two adjoint Wilson fermions: The twisted reduced model of large $N$ QCD with two adjoint Wilson fermions\nis studied numerically using the Hybrid Monte Carlo method. This is the\none-site model, whose large $N$ limit (large volume limit) is expected to be\nconformal or nearly conformal. The symmetric twist boundary condition with flux\n$k$ is used. $k$=0 corresponds to periodic boundary conditions. It is shown\nthat the quark mass and $N$ dependencies of the model with non-vanishing $k$\ndiffer significantly from those of the $k$=0 model. A preliminary result for\nthe string tension calculated at $N$=289 is presented. The string tension seems\nto vanish as the physical quark mass decreases to zero in a way consistent with\nthe theory being governed by an infrared fixed point with $\\gamma_* = 0.8 \\sim\n1.2$."
    },
    {
        "anchor": "Scale setting for $\\mathcal{N} = 1$ SUSY Yang-Mills at large-$N$ through\n  volume-reduced twisted matrix model: $\\mathcal{N}=1$ SUSY Yang-Mills theory is an appealing theoretical framework\nthat has been studied in the literature using different methods, including\nstandard lattice simulations. Among these, the volume-reduced twisted\nEguchi-Kawai model, endowed with one adjoint Majorana fermion, could play an\nimportant role in studying its large-$N$ limit via the Curci-Veneziano\nprescription. In this talk, we present our results on the analysis of the scale\nof the theory, performed via different methods based on purely gluonic\nobservables as well as (quenched) fundamental mesons in the chiral limit. These\nlattice results will be used as a scale setting for the analysis of the\nspectrum of the theory.",
        "positive": "$O(a)$ Improvement for Quenched Wilson Fermions: We briefly describe some of our recent results for the mass spectrum and\nmatrix elements using $O(a)$ improved fermions for quenched QCD. Where possible\na comparison is made between improved and Wilson fermions."
    },
    {
        "anchor": "Latest results from lattice QCD for exotic hybrid mesons: I review the results from lattice gauge theory for the masses of exotic\nhybrid mesons.",
        "positive": "Accessing high-momentum nucleons with dilute stochastic sources: A novel stochastic technique combining a dilute source grid of $\\mathbb{Z}_3$\nnoise with iterative momentum-smearing is used to study the proton correlation\nfunction at rest and in boosted frames on two lattice volumes. The technique\nmakes use of the baryonic version of the so-called one-end trick, and the\ndecomposition into signal and noise terms of the resulting stochastic proton\ncorrelation function is made explicit. The number and location of the source\npoints in the dilute grid should be chosen so that the benefits of averaging\nover many locations overcomes the additional statistical error introduced by\nthe noise terms in the desired fitting region. At all nontrivial momentum\nvalues considered we find that the choice of $N=4$--$8$ maximally separated\nsource locations is shown to be optimal, providing a reduced statistical error\nwhen compared with a single point source. This enables us to successfully fit\nthe proton energy at momentum values as high as $|\\vec{p}| \\simeq 3.75$ GeV and\n$|\\vec{p}| \\simeq 2.82$ GeV on the small and large volume respectively."
    },
    {
        "anchor": "Spectral reconstruction details of a gradient-flowed color-electric\n  correlator: In a recently published work we provide a proof-of-concept of a novel method\nto extract the heavy quark momentum diffusion coefficient from color-electric\ncorrelators on the lattice using gradient flow. The transport coefficient can\nbe found in the infrared limit of the corresponding spectral function which is\nreconstructed through perturbative model fits of the correlator data. In this\nproceedings report we want to give more detailed insights into the systematic\nuncertainties of this procedure and compare our results with other studies.",
        "positive": "Simulating $\\mathbb{Z}_2$ lattice gauge theory on a quantum computer: The utility of quantum computers for simulating lattice gauge theories is\ncurrently limited by the noisiness of the physical hardware. Various quantum\nerror mitigation strategies exist to reduce the statistical and systematic\nuncertainties in quantum simulations via improved algorithms and analysis\nstrategies. We perform quantum simulations of $1+1d$ $\\mathbb{Z}_2$ gauge\ntheory with matter to study the efficacy and interplay of different error\nmitigation methods: readout error mitigation, randomized compiling, rescaling,\nand dynamical decoupling. We compute Minkowski correlation functions in this\nconfining gauge theory and extract the mass of the lightest spin-1 state from\nfits to their time dependence. Quantum error mitigation extends the range of\ntimes over which our correlation function calculations are accurate by a factor\nof six and is therefore essential for obtaining reliable masses."
    },
    {
        "anchor": "In-medium quarkonium properties from a lattice QCD based effective field\n  theory: In order to understand the experimental data on heavy quarkonium production\nin heavy ion collisions at RHIC and LHC it is necessary (though not sufficient)\nto pinpoint the properties of heavy $Q\\bar{Q}$ bound states in the deconfined\nquark-gluon plasma, including their dissolution. Here we present recent results\non the temperature dependence of bottomonium and charmonium correlators, as\nwell as their spectral functions in a lattice QCD based effective field theory\ncalled NRQCD, surveying temperatures close to the crossover transition $140\n{\\rm MeV} < T< 249 {\\rm MeV}$. The spectra are reconstructed based on a novel\nBayesian prescription, whose systematic uncertainties are assessed. We present\nindications for sequential melting of different quarkonium species with respect\nto their vacuum binding energies and give estimates on the survival of S-wave\nand P-wave ground states.",
        "positive": "Controlling the Sign Problem in Finite Density Quantum Field Theory: Quantum field theories at finite matter densities generically possess a\npartition function that is exponentially suppressed with the volume compared to\nthat of the phase quenched analogue. The smallness arises from an almost\nuniform distribution for the phase of the fermion determinant. Large\ncancellations upon integration is the origin of a poor signal to noise ratio.\nWe study three alternatives for this integration: the Gaussian approximation,\nthe \"telegraphic\" approximation, and a novel expansion in terms of\ntheory-dependent moments and universal coefficients. We have tested the methods\nfor QCD at finite densities of heavy quarks. We find that for two of the\napproximations the results are extremely close - if not identical - to the full\nanswer in the strong sign problem regime."
    },
    {
        "anchor": "The Ising transition in 2D simplicial quantum gravity - can Regge\n  calculus be right?: We report a high statistics simulation of Ising spins coupled to 2D quantum\ngravity in the Regge calculus approach using triangulated tori with up to\n$512^2$ vertices. For the constant area ensemble and the $dl/l$ functional\nmeasure we definitively can exclude the critical exponents of the Ising phase\ntransition as predicted for dynamically triangulated surfaces. We rather find\nclear evidence that the critical exponents agree with the Onsager values for\nstatic regular lattices, independent of the coupling strength of an $R^2$\ninteraction term. For exploratory simulations using the lattice version of the\nMisner measure the situation is less clear.",
        "positive": "The quark-mass dependence of the potential energy between static colour\n  sources in the QCD vacuum with light and strange quarks: The low-lying energy spectrum of the static-colour-source-anti-source system\nin a vacuum containing light and strange quarks is computed using lattice QCD\nfor a range of different light quark masses. The resulting levels are described\nusing a simple model Hamiltonian and the parameters in this model are\nextrapolated to the physical light-quark masses. In this framework, the QCD\nstring tension is found to be $\\sqrt{\\sigma}=445(3)_{\\rm stat}(6)_{\\rm sys}$\nMeV."
    },
    {
        "anchor": "The QCD Chiral Condensate from the Lattice: We determine the chiral condensate from simulations of quenched lattice QCD\nwith Wilson fermions. Our measurements have been obtained with high statistics\nat three values of the gauge coupling, corresponding to UV cutoffs in the range\n2 - 4 GeV. Several improvements have been made with respect to earlier lattice\ncomputations. The most important are the non-perturbative renormalization of\nthe condensate, the use of the tree-level improved Clover action and the\nreduction of the systematic error due to uncertainties in the lattice\ncalibration. Our result for the chiral condensate in the $\\msbar$ scheme is\n  (\\bar\\psi \\psi)^{\\msbar}(mu = 2 GeV)\n  = - 0.0147(8)(16)(12) GeV^3\n  = - [245(4)(9)(7) MeV]^3\n  where the first error is statistical, the second is due to the\nnon-perturbative renormalization and the third due to the lattice calibration.",
        "positive": "Quark mass dependence of the pseudoscalar hairpin vertex: In a recent investigation of chiral behavior in quenched lattice QCD, the\nflavor-singlet pseudoscalar ``hairpin'' vertex associated with the eta prime\nmass was studied for pion masses ranging from approximately 275 to 675 MeV.\nThroughout this mass range, the quark-disconnected pseudoscalar correlator is\nwell-described by a pure double-pion-pole diagram with a p^2 independent mass\ninsertion. The residue of the double pole was found to exhibit a significant\nquark mass dependence, evidenced by a negative slope of the effective mass\ninsertion (m_0^{eff})^2 as a function of m_{\\pi}^2. It has been observed by\nSharpe that, with a consistent NLO calculation in quenched chiral perturbation\ntheory, this mass dependence is uniquely predicted in terms of the single-pole\ncoefficient \\alpha_{\\Phi} and the Leutwyler parameter L_5. Since \\alpha_{\\Phi}\nis found to be approximately zero, the chiral slope of the double-pole residue\ndetermines a value for L_5. This provides a consistency check between the\nchiral slope of the hairpin mass insertion and that of the pion decay constant.\nWe investigate the consistency of these mass dependences in our Monte Carlo\nresults at two values of lattice spacing. Within statistics, the slopes are\nfound to be consistent with the Q\\chiPT prediction, confirming that the\nobserved negative slope of m_0^{eff} arises as an effect of the L_5 Leutwyler\nterm."
    },
    {
        "anchor": "B-meson decay constants: a more complete picture from full lattice QCD: We extend the picture of $B$-meson decay constants obtained in lattice QCD\nbeyond those of the $B$, $B_s$ and $B_c$ to give the first full lattice QCD\nresults for the $B^*$, $B^*_s$ and $B^*_c$. We use improved NonRelativistic QCD\nfor the valence $b$ quark and the Highly Improved Staggered Quark (HISQ) action\nfor the lighter quarks on gluon field configurations that include the effect of\n$u/d$, $s$ and $c$ quarks in the sea with $u/d$ quark masses going down to\nphysical values. For the ratio of vector to pseudoscalar decay constants, we\nfind $f_{B^*}/f_B$ = 0.941(26), $f_{B^*_s}/f_{B_s}$ = 0.953(23) (both $2\\sigma$\nless than 1.0) and $f_{B^*_c}/f_{B_c}$ = 0.988(27). Taking correlated\nuncertainties into account we see clear indications that the ratio increases as\nthe mass of the lighter quark increases. We compare our results to those using\nthe HISQ formalism for all quarks and find good agreement both on decay\nconstant values when the heaviest quark is a $b$ and on the dependence on the\nmass of the heaviest quark in the region of the $b$. Finally, we give an\noverview plot of decay constants for gold-plated mesons, the most complete\npicture of these hadronic parameters to date.",
        "positive": "Spin-3/2 baryons from an anisotropic lattice QCD action: The mass spectrum of baryons in the spin-3/2 sector is computed in quenched\nlattice QCD using a tadpole-improved anisotropic action. Both isospin 1/2 and\n3/2 (the traditional decuplet) are considered, as well as members that contain\nstrange quarks. States with positive and negative parities are isolated by\nparity projection, while states with spin-3/2 and spin-1/2 are separated by\nspin projection. The extent to which spin projection is needed is examined. The\nissue of optimal interpolating field is also investigated. The results are\ndiscussed in relation to previous calculations and experiment."
    },
    {
        "anchor": "Hadron matrix elements for nucleon decay with the Wilson quark action: We report preliminary results of our study of matrix elements of baryon\nnumber violating operators which appear in the low-energy effective Lagrangian\nof (SUSY-)Grand Unified Theories. The calculation is performed on a\n$32^{3}\\times80$ lattice at $\\beta=6.1$ using Wilson fermions in the quenched\napproximation. Our calculation is independent of details of (SUSY-)GUT models\nand covers all interesting decay modes.",
        "positive": "Chiral properties of (2+1)-flavor QCD in strong magnetic fields at zero\n  temperature: We present lattice QCD results for masses and magnetic polarizabilities of\nlight and strange pseudoscalar mesons, chiral condensates, decay constants of\nneutral pion, and neutral kaon in the presence of background magnetic fields\nwith $eB$ ranging up to around 3.35 GeV$^2$ ($\\sim70~M_\\pi^2$) in the vacuum.\nThe computations were carried out in (2+1)-flavor QCD mostly on $32^3 \\times\n96$ lattices using the highly improved staggered quark action with $M_{\\pi}\n\\approx $ 220 MeV at zero temperature. We find that the masses of neutral\npseudoscalar mesons monotonously decrease as the magnetic field strength grows\nand then saturate at a nonzero value, while there exists a nonmonotonous\nbehavior of charged pion and kaon masses in the magnetic field. We observe a\n$qB$ scaling of the up and down quark flavor components of neutral pion mass,\nneutral pion decay constant as well as the quark chiral condensates at 0.05\n$\\lesssim eB\\lesssim$ 3.35 GeV$^2$. We show that the correction to the\nGell-Mann-Oakes-Renner relation involving the neutral pion is less than 6% and\nthe correction for the relation involving neutral kaon is less than 30% at\n$eB\\lesssim$ 3.35 GeV$^2$. We also derive the Ward-Takahashi identities for QCD\nin the magnetic field in the continuum formulation including the relation\nbetween integrated neutral pseudoscalar meson correlators and chiral\ncondensates."
    },
    {
        "anchor": "Supersymmetric QCD on the Lattice: An Exploratory Study: We perform a pilot study of the perturbative renormalization of a\nSupersymmetric gauge theory with matter fields on the lattice. As a specific\nexample, we consider Supersymmetric ${\\cal N}{=}1$ QCD (SQCD). We study the\nself-energies of all particles which appear in this theory, as well as the\nrenormalization of the coupling constant. To this end we compute,\nperturbatively to one-loop, the relevant two-point and three-point Green's\nfunctions using both dimensional and lattice regularizations. Our lattice\nformulation involves the Wilson discretization for the gluino and quark fields;\nfor gluons we employ the Wilson gauge action; for scalar fields (squarks) we\nuse na\\\"ive discretization. The gauge group that we consider is $SU(N_c)$,\nwhile the number of colors, $N_c$, the number of flavors, $N_f$, and the gauge\nparameter, $\\alpha$, are left unspecified.\n  We obtain analytic expressions for the renormalization factors of the\ncoupling constant ($Z_g$) and of the quark ($Z_\\psi$), gluon ($Z_u$), gluino\n($Z_\\lambda$), squark ($Z_{A_\\pm}$), and ghost ($Z_c$) fields on the lattice.\nWe also compute the critical values of the gluino, quark and squark masses.\nFinally, we address the mixing which occurs among squark degrees of freedom\nbeyond tree level: we calculate the corresponding mixing matrix which is\nnecessary in order to disentangle the components of the squark field via an\nadditional finite renormalization.",
        "positive": "Worm Algorithm for CP(N-1) Model: The CP(N-1) model in 2D is an interesting toy model for 4D QCD as it\npossesses confinement, asymptotic freedom and a non-trivial vacuum structure.\nDue to the lower dimensionality and the absence of fermions, the computational\ncost for simulating 2D CP(N-1) on the lattice is much lower than that for\nsimulating 4D QCD. However, to our knowledge, no efficient algorithm for\nsimulating the lattice CP(N-1) model has been tested so far, which also works\nat finite density. To this end we propose a new type of worm algorithm which is\nappropriate to simulate the lattice CP(N-1) model in a dual, flux-variables\nbased representation, in which the introduction of a chemical potential does\nnot give rise to any complications. In addition to the usual worm moves where a\ndefect is just moved from one lattice site to the next, our algorithm\nadditionally allows for worm-type moves in the internal variable space of\nsingle links, which accelerates the Monte Carlo evolution. We use our algorithm\nto compare the two popular CP(N-1) lattice actions and exhibit marked\ndifferences in their approach to the continuum limit."
    },
    {
        "anchor": "Details of a staggered fermion data analysis: We present technical details of an analysis of pseudo-scalar data from a QCD\nsimulation with staggered fermions. The data were obtained close to the\nphysical point with an inverse lattice spacing of about 3 GeV, and $N_f=2+1+1$.\nWe compare different methods of extracting effective masses and decay constants\nin lattice units. The results of several correlated and uncorrelated fitting\nmethods are compared, both on the simulated data set, and on a synthetically\ngenerated data set.",
        "positive": "Nonrelativistic lattice study of stoponium: We calculate the bound state properties of stoponium using lattice\nformulation of nonrelativistic effective field theory for stop which is moving\nnonrelativistically in the rest frame of stoponium. Our calculation method is\nsimilar to that employed in lattice nonrelativistic quantum chromodynamics\n(NRQCD) studies for charmonium and bottominum. Using $16^3 \\times 256$ quenched\nlattice gauge field configurations at $a^{-1} = 50(1) {\\rm GeV}$, we obtain the\nstopoinium mass and the lattice matrix element which is related to the\nwavefunction at the origin for the $1S$ state and find that the lattice\n$|R_{1S} (0)|^2/M_{1S}^3$ is $3.5 \\sim 4$ larger than that from a potential\nmodel calculation for $200 {\\rm GeV} \\le M_{1S} \\le 800 {\\rm GeV}$."
    },
    {
        "anchor": "Field theoretic study of a cold Fermi gas in the unitary limit: Trapped and cooled gases of alkali atoms can be manipulated to exhibit a\nvariety of interesting phenomena. For example, dilute gases of fermionic atoms,\nin 2 hyperfine states, can be cooled to temperatures where they become\nsuperfluid. An external field can be applied to tune the scattering length a.\nWhen |a| exceeds the interparticle spacing, nonperturbative tools are needed to\nstudy the system theoretically. The unitary limit, |a|\\to\\infty, is\nparticularly interesting due to its universality and symmetry. Lattice field\ntheory and effective field theory can be used to systematically calculate\nproperties of this system. Results are presented for the finite temperature\nphase transition and for behavior near zero temperature.",
        "positive": "External magnetic fields in gauge theories: A general discussion is presented of the response of a gauge-field system to\nexternal magnetic fields, in the light of a theorem due to S. Elitzur. As a\nresult a natural understanding emerges of some recent puzzling results from\nlattice MC simulations, as well as of the phenomenon of ``perfect\ndiamagnetism'' of non-abelian gauge theories, discovered almost ten years ago."
    },
    {
        "anchor": "Scattering phases on finite lattices in the broken phase of the\n  four-dimensional O(4)-\u03c6^4 theory: According to a proposal of Luescher it is possible to determine elastic\nscattering phases in infinite volume from the energy spectrum of two-particle\nstates in a periodic box. We demonstrate the applicability of this method in\nthe broken phase of the four-dimensional O(4) non-linear sigma-model in a Monte\nCarlo study on finite lattices. This non-perturbative approach also permits the\nstudy of unstable particles, the sigma-particle in our case. We observe the\nsigma-resonance and extract its mass and width. In all scattering channels\ninvestigated the results are completely consistent with perturbative\ncalculations.",
        "positive": "Three-dimensional finite temperature Z$_2$ gauge theory with tensor\n  network scheme: We apply a tensor network scheme to finite temperature Z$_2$ gauge theory in\n2+1 dimensions. Finite size scaling analysis with the spatial extension up to\n$N_{\\sigma}=4096$ at the temporal extension of $N_\\tau=2,3,5$ allows us to\ndetermine the transition temperature and the critical exponent $\\nu$ at high\nlevel of precision, which shows the consistency with the Svetitsky-Yaffe\nconjecture."
    },
    {
        "anchor": "A nested Krylov subspace method to compute the sign function of large\n  complex matrices: We present an acceleration of the well-established Krylov-Ritz methods to\ncompute the sign function of large complex matrices, as needed in lattice QCD\nsimulations involving the overlap Dirac operator at both zero and nonzero\nbaryon density. Krylov-Ritz methods approximate the sign function using a\nprojection on a Krylov subspace. To achieve a high accuracy this subspace must\nbe taken quite large, which makes the method too costly. The new idea is to\nmake a further projection on an even smaller, nested Krylov subspace. If\nadditionally an intermediate preconditioning step is applied, this projection\ncan be performed without affecting the accuracy of the approximation, and a\nsubstantial gain in efficiency is achieved for both Hermitian and non-Hermitian\nmatrices. The numerical efficiency of the method is demonstrated on lattice\nconfigurations of sizes ranging from 4^4 to 10^4, and the new results are\ncompared with those obtained with rational approximation methods.",
        "positive": "Overlap of the Wilson loop with the broken-string state: Numerical experiments on most gauge theories coupled with matter failed to\nobserve string-breaking effects while measuring Wilson loops only. We show\nthat, under rather mild assumptions, the overlap of the Wilson loop operator\nwith the broken-string state obeys a natural upper bound implying that the\nsignal of string-breaking is in general too weak to be detected by the\nconventional updating algorithms.\n  In order to reduce the variance of the Wilson loops in 3-D Z_2 gauge Higgs\nmodel we use a new algorithm based on the L\\\"uscher-Weisz method combined with\na non-local cluster algorithm which allows to follow the decay of rectangular\nWilson loops up to values of the order of 10^{-24}. In this way a sharp signal\nof string breaking is found."
    },
    {
        "anchor": "Three particles on the lattice: I give a review of existing frameworks, which are designed to analyse lattice\ndata in the three-particle sector. A particular emphasis is laid on the\nfoundations of the theory, where the separation of the short- and long-range\neffects plays a central role. It is shown that the use of the effective field\ntheory approach enables one to carry out this separation in a natural and\nefficient way. In conclusion, a few examples of the analysis of lattice data\nare considered for illustration.",
        "positive": "Propagators of hot SU(2) gauge theory from 3d adjoint Higgs model: We study propagators of the lattice 3d adjoint Higgs model, considered as an\neffective theory of 4d SU(2) gauge theory at high temperature. The propagators\nare calculated in so-called lambda-gauges. From the long distance behaviour of\nthe propagators we extract the screening masses. It is shown that the pole\nmasses extracted from the propagators agree well with the screening masses\nobtained recently in finite temperature SU(2) theory. The gauge dependence of\nthe screening masses is also discussed."
    },
    {
        "anchor": "Dynamics of the Conformal Mode and Simplicial Gravity: We review the derivation of the Liouville action in 2DQG via the trace\nanomaly and emphasize how a similar approach can be used to derive an effective\naction describing the long wavelength dynamics of the conformal factor in 4D.\nIn 2D we describe how to make an explicit connection between dynamical\ntriangulations and this continuum theory, and present results which confirm the\nequivalance of the two approaches. By reconstructing a lattice conformal mode\nfrom DT simulations it should be possible to test this equivalence in 4D also.",
        "positive": "Another look at the Landau-gauge gluon and ghost propagators at low\n  momentum: We study the gluon and ghost propagators of SU(2) lattice Landau gauge theory\nand find their low-momentum behavior being sensitive to the lowest non-trivial\neigenvalue (\\lambda_1) of the Faddeev-Popov operator. If the gauge-fixing\nfavors Gribov copies with small (large) values for \\lambda_1 both the ghost\ndressing function and the gluon propagator get enhanced (suppressed) at low\nmomentum. For larger momenta no dependence on Gribov copies is seen. We compare\nour lattice data to the corresponding (decoupling) solutions from the DSE/FRGE\nstudy of Fischer, Maas and Pawlowski [Annals Phys. 324 (2009) 2408] and find\nqualitatively good agreement."
    },
    {
        "anchor": "Incorporating Chiral Symmetry and Heavy Quark Theory in Extrapolations\n  of Octet Baryon Charge Radii: We extrapolate lattice calculations of electric charge radii of the spin-1/2\nbaryon octet to the physical regime. The extrapolation procedure incorporates\nchiral perturbation theory and heavy quark effective theory in the appropriate\nlimits. In particular, this procedure includes the non-analytic, logarithmic\nterms from pion loops. The electric charge radii of the nucleons and $\\Sigma^-$\nobtained from the chiral extrapolations agree well with experimental data. We\nmake predictions for the charge radii of the remaining baryons in anticipation\nof future experimental measurements.",
        "positive": "Unification of the complex Langevin method and the Lefschetz-thimble\n  method: Recently there has been remarkable progress in solving the sign problem,\nwhich occurs in investigating statistical systems with a complex weight. The\ntwo promising methods, the complex Langevin method and the Lefschetz thimble\nmethod, share the idea of complexifying the dynamical variables, but their\nrelationship has not been clear. Here we propose a unified formulation, in\nwhich the sign problem is taken care of by both the Langevin dynamics and the\nholomorphic gradient flow. We apply our formulation to a simple model in three\ndifferent ways and show that one of them interpolates the two methods by\nchanging the flow time."
    },
    {
        "anchor": "Lattice gauge symmetry in neural networks: We review a novel neural network architecture called lattice gauge\nequivariant convolutional neural networks (L-CNNs), which can be applied to\ngeneric machine learning problems in lattice gauge theory while exactly\npreserving gauge symmetry. We discuss the concept of gauge equivariance which\nwe use to explicitly construct a gauge equivariant convolutional layer and a\nbilinear layer. The performance of L-CNNs and non-equivariant CNNs is compared\nusing seemingly simple non-linear regression tasks, where L-CNNs demonstrate\ngeneralizability and achieve a high degree of accuracy in their predictions\ncompared to their non-equivariant counterparts.",
        "positive": "Lattice formulation of (2,2) supersymmetric gauge theories with matter\n  fields: We construct lattice actions for a variety of (2,2) supersymmetric gauge\ntheories in two dimensions with matter fields interacting via a superpotential."
    },
    {
        "anchor": "Nuclear Force from Lattice QCD: The first lattice QCD result on the nuclear force (the NN potential) is\npresented in the quenched level. The standard Wilson gauge action and the\nstandard Wilson quark action are employed on the lattice of the size 16^3\\times\n24 with the gauge coupling beta=5.7 and the hopping parameter kappa=0.1665. To\nobtain the NN potential, we adopt a method recently proposed by CP-PACS\ncollaboration to study the pi pi scattering phase shift. It turns out that this\nmethod provides the NN potentials which are faithful to those obtained in the\nanalysis of NN scattering data. By identifying the equal-time Bethe-Salpeter\nwave function with the Schroedinger wave function for the two nucleon system,\nthe NN potential is reconstructed so that the wave function satisfies the\ntime-independent Schroedinger equation. In this report, we restrict ourselves\nto the J^P=0^+ and I=1 channel, which enables us to pick up unambiguously the\n``central'' NN potential V_{central}(r). The resulting potential is seen to\nposses a clear repulsive core of about 500 MeV at short distance (r < 0.5 fm).\nAlthough the attraction in the intermediate and long distance regions is still\nmissing in the present lattice set-up, our method is appeared to be quite\npromising in reconstructing the NN potential with lattice QCD.",
        "positive": "SU(2) Gluodynamics and HP1 sigma-model embedding: Scaling, Topology and\n  Confinement: We investigate recently proposed HP1 sigma-model embedding method aimed to\nstudy the topology of SU(2) gauge fields. The HP1 based topological charge is\nshown to be fairly compatible with various known definitions. We study the\ncorresponding topological susceptibility and estimate its value in the\ncontinuum limit. The geometrical clarity of HP1 approach allows to investigate\nnon-perturbative aspects of SU(2) gauge theory on qualitatively new level. In\nparticular, we obtain numerically precise estimation of gluon condensate and\nits leading quadratic correction. Furthermore, we present clear evidences that\nthe string tension is to be associated with global (percolating) regions of\nsign-coherent topological charge. As a byproduct of our analysis we estimate\nthe continuum value of quenched chiral condensate and the dimensionality of\nregions, which localize the lowest eigenmodes of overlap Dirac operator."
    },
    {
        "anchor": "Quarks and Triality in a Finite Volume: In order to understand the puzzle of the free energy of an individual quark\nin QCD, we explicitly construct ensembles with quark numbers $N_V\\neq 0\\!\\mod\n3$, corresponding to non-zero triality in a finite subvolume $V$ on the\nlattice. We first illustrate the basic idea in an effective Polyakov-loop\ntheory for the heavy-dense limit of QCD, and then extend the construction to\nfull Lattice QCD, where the electric center flux through the surface of $V$ has\nto be fixed at all times to account for Gauss's law. This requires introducing\ndiscrete Fourier transforms over closed center-vortex sheets around the spatial\nvolume $V$ between all subsequent time slices, and generalizes the construction\nof 't Hooft's electric fluxes in the purge gauge theory. We derive this same\nresult from a dualization of the Wilson fermion action, and from the transfer\nmatrix formulation with a local $\\mathbb Z_3$-Gauss law to restrict the\ndynamics to sectors with the required center charge in $V$.",
        "positive": "What We Do Understand of Colour Confinement: The status of our understanding of confinement is reviewed. The evidence from\nlattice is that monopole condensation, or dual superconductivity, is at work.\nConfinement is an order-disorder transition. Different monopole species look\nequivalent, indicating that the symmetry of the disordered phase is more\ninteresting that we understand."
    },
    {
        "anchor": "Impossibility of spontaneous vector flavor symmetry breaking on the\n  lattice: I show that spontaneous breaking of vector flavor symmetry on the lattice is\nimpossible in gauge theories with a positive functional-integral measure, for\ndiscretized Dirac operators linear in the quark masses, if the corresponding\npropagator and its commutator with the flavor symmetry generators can be\nbounded in norm independently of the gauge configuration and uniformly in the\nvolume. Under these assumptions, any order parameter vanishes in the symmetric\nlimit of fermions of equal masses. I show that these assumptions are satisfied\nby staggered, minimally doubled and Ginsparg-Wilson fermions for positive\nfermion mass, for any value of the lattice spacing, and so in the continuum\nlimit if this exists. They are instead not satisfied by Wilson fermions, for\nwhich spontaneous vector flavor symmetry breaking is known to take place in the\nAoki phase. The existence of regularizations unaffected by residual fermion\ndoubling for which the symmetry cannot break spontaneously on the lattice\nestablishes rigorously (at the physicist's level) the impossibility of its\nspontaneous breaking in the continuum for any number of flavors.",
        "positive": "Putting M theory on a computer: We propose a non-lattice simulation for studying supersymmetric matrix\nquantum mechanics in a non-perturbative manner. In particular, our method\nenables us to put M theory on a computer based on its matrix formulation\nproposed by Banks, Fischler, Shenker and Susskind. Here we present Monte Carlo\nresults of the same matrix model but in a different parameter region, which\ncorresponds to the 't Hooft large-N limit at finite temperature. In the strong\ncoupling limit the model has a dual description in terms of the N D0-brane\nsolution in 10d type IIA supergravity. Our results provide highly nontrivial\nevidences for the conjectured duality. In particular, the energy (and hence the\nentropy) of the non-extremal black hole has been reproduced by solving directly\nthe strongly coupled dynamics of the D0-brane effective theory."
    },
    {
        "anchor": "Lattice QCD without tuning, mixing and current renormalization: The classically perfect action of QCD requires no tuning to get the pion\nmassless in the broken phase: the critical bare mass $m_q^c$ is zero. Neither\nthe vector nor the flavour non-singlet axial vector currents need\nrenormalization. Further, there is no mixing between four-fermion operators in\ndifferent chiral representations. The order parameter of chiral symmetry\nrequires, however, a subtraction which is given here explicitly. These results\nare based on the fact that the fixed point action satisfies the Ginsparg-Wilson\nremnant chiral symmetry condition. On chiral symmetry related questions any\nother local solution of this condition will produce similar results.",
        "positive": "Computation of the Kugo-Ojima function from lattice simulations: In addition to its connection with a standard confinement criterion, the\nKugo-Ojima function constitutes an indispensable component in a multitude of\napplications in the gauge sector of QCD. In the present work we report on\npreliminary results of an ongoing large-volume lattice simulation of this\nspecial function. In particular, the volume-dependence of the data is studied\nin detail, and a comparison with results obtained from Schwinger-Dyson\nequations is carried out."
    },
    {
        "anchor": "Direct Proof of Reflection Positivity of Free Overlap Dirac Fermion: It is shown that free lattice Dirac fermions defined by overlap Dirac\noperator fulfill the Osterwalder-Schrader reflection positivity condition with\nrespect to the link-reflection.",
        "positive": "Complex Probability Distributions: A Solution for the Long-Standing\n  Problem of QCD at Finite Density: We show how the prescription of taking the absolute value of the fermion\ndeterminant in the integration measure of QCD at finite density, forgetting its\nphase, reproduces the correct thermodynamical limit. This prescription, which\napplies also to other gauge theories with non-positive-definite integration\nmeasure, also has the advantage of killing finite size effects due to extremely\nsmall mean values of the cosine of the phase of the fermion determinant. We\nalso give an explanation for the pathological behaviour of quenched QCD at\nfinite density."
    },
    {
        "anchor": "Wilson fermions at fine lattice spacings: scale setting, pion form\n  factors and (g-2)_mu: We present an update on our on-going project to compute hadronic observables\nfor Nf=2 flavours of O(a) improved Wilson fermions at small lattice spacings.\nThe procedure to determine the lattice scale via the mass of the Omega baryon\nis described. Furthermore we present preliminary results for the pion form\nfactor computed using twisted boundary conditions, and report on the\nimplementation of a novel approach to determine the contribution of the\nhadronic vacuum polarisation to the anomalous magnetic moment of the muon.",
        "positive": "The Wiener-Hermite expansions of the Langevin transitions: New partial differential equations for the Wiener-Hermite expansions of the\nLangevin (stochastic) transitions are formulated. They are solved recursively\nin full order series solutions with respect to $\\sqrt{t}$. A sort of 'gauge'\ndegrees of freedom (arbitrariness) involved in the solutions are analyzed and\nclarified. The Wiener-Hermite expansions play important roles as basic elements\nof numerical simulations of the Langevin equations. Specific solutions within\nsome orders are presented as examples. These expansions giving integral\nrepresentations of the Fokker-Planck evolution kernels, similar formulations\nare possible for the imaginary time Hamiltonian evolution kernels as well."
    },
    {
        "anchor": "Complex Langevin studies of the dynamical compactification of extra\n  dimensions in the Euclidean IKKT matrix model: The type IIB matrix model, also known as the IKKT matrix model, is a\npromising candidate for a nonperturbative formulation of superstring theory. In\nthis talk we study the Euclidean version of the IKKT matrix model, which has a\n\"sign problem\" due to the Pfaffian coming from integrating out the fermionic\ndegrees of freedom. To study the spontaneous breaking of the SO(10) rotational\nsymmetry, we apply the Complex Langevin Method (CLM) to the Euclidean IKKT\nmatrix model. We conclude that the SO(10) symmetry is broken to SO(3), in\nagreement with the previous studies by the Gaussian Expansion Method (GEM). We\nalso apply the GEM to the deformed model and find consistency with the CLM\nresult. These are proceedings of Takehiro Azuma's talk at Asia-Pacific\nSymposium for Lattice Field Theory (APLAT 2020) on August 4-7, 2020, based on\nthe paper arXiv:2002.07410.",
        "positive": "Color Confinement in lattice Landau gauge with unquenched Wilson and KS\n  fermions: The Kugo-Ojima confinement criterion is verified in the unquenched Landau\ngauge QCD simulation. The valence quark propagator of the Kogut-Susskind\nfermion with use of the fermion action including the Naik term and the staple\ncontribution is calculated on MILC Asqtad unquenched gauge configurations, and\nit shows infrared suppression of the quark propagator."
    },
    {
        "anchor": "Sea quark QED effects and twisted mass fermions: We show that maximally twisted mass fermions can be employed to regularize on\nthe lattice the fully unquenched QCD+QED theory with vanishing $\\theta$-term.\nWe discuss how the critical mass of the up and down quarks can be conveniently\ndetermined beyond the electroquenched approximation by imposing that certain\nsymmetries of continuum QCD+QED, which are broken by Wilson terms, get restored\nin the continuum limit. A mixed action setup is outlined that allows to extend\nbeyond the electroquenched approximation the computation (with only O($a^2$)\nartifacts) of the leading isospin breaking corrections to physical observables\nusing the RM123 method and (pure QCD) ETMC gauge ensembles with $N_f=2+1+1$\ndynamical quark flavours.",
        "positive": "Light meson spectrum with $N_f=2+1$ dynamical overlap fermions: We report on a numerical simulation with 2+1 dynamical flavors of overlap\nfermions. We calculate pseudo-scalar masses and decay constants on a\n$16^3\\times 48 \\times (0.11 {\\rm fm})^4$ lattice at five different up and down\nquark masses and two strange quark masses. The lightest pion mass corresponds\nto $\\approx 310$ MeV. We also study the validity of the chiral perturbation\ntheory using the results of the numerical simulation with two dynamical flavors\nand conclude that the one-loop formulae cannot be directly applied in the\nstrange quark mass region. We therefore extrapolate our 2+1-flavor results to\nthe chiral limit by fitting the data to the two-loop formulae of the chiral\nperturbation theory."
    },
    {
        "anchor": "Spinodal Decomposition in High Temperature Gauge Theories: After a rapid increase in temperature across the deconfinement temperature $%\nT_{d}$, pure gauge theories exhibit unstable long wavelength fluctuations in\nthe approach to equilibrium. This phenomenon is analogous to spinodal\ndecomposition observed in condensed matter physics, and also seen in models of\ndisordered chiral condensate formation. At high temperature, the unstable modes\noccur only in the range $0\\leq k$ $\\leq k_{c}$, where $k_{c}$ is on the order\nof the Debye screening mass $m_D$. Equilibration always occurs via spinodal\ndecomposition for $SU(2) $at temperatures $T>T_{d}$ and for SU(3) for $T\\gg\nT_{d}$. For SU(3) at temperatures $T\\gtrsim T_{d}$, nucleation may replace\nspinodal decomposition as the dominant equilibration mechanism. Monte Carlo\nsimulations of SU(2) lattice gauge theory exhibit the predicted phenomena. The\nobserved value of $k_c$ is in reasonable agreement with a value predicted from\nprevious lattice measurements of $m_D$.",
        "positive": "The Relationship of the Laplacian Gauge to the Landau Gauge: The Laplacian gauge for gauge group SU(N) is discussed in perturbation\ntheory. It is shown that to the lowest non-trivial order, O(g^1),\nconfigurations in the Laplacian gauge automatically satisfy the (finite\ndifference) Landau gauge condition. Laplacian gauge fixed configurations are\nexamined numerically and it is seen that to O(g^2) they do not remain in the\nLandau gauge."
    },
    {
        "anchor": "Recent progress in lattice QCD at finite density: We review recent progress in lattice QCD at finite density. The phase diagram\nof QCD and the equation of state at finite temperature and density are\ndiscussed. In particular, we focus on the critical point terminating a first\norder phase transition line in the high density region. The critical point is\none of the most interesting features that may be discovered in heavy-ion\ncollision experiments. We summarize the current discussion on the existence of\na critical point in the QCD phase diagram and discuss some attempts to find the\ncritical point by numerical simulations.",
        "positive": "Two-dimensional ${\\cal N} = (2, 2)$ Lattice Gauge Theories with Matter\n  in Higher Representations: We construct two-dimensional ${\\cal N} = (2, 2)$ supersymmetric gauge\ntheories on a Euclidean spacetime lattice with matter in the two-index\nsymmetric and anti-symmetric representations of SU($N_c$) color group. These\nlattice theories preserve a subset of the supercharges exact at finite lattice\nspacing. The method of topological twisting is used to construct such theories\nin the continuum and then the geometric discretization scheme is used to\nformulate them on the lattice. The lattice theories obtained this way are\ngauge-invariant, free from fermion doubling problem and exact supersymmetric at\nfinite lattice spacing. We hope that these lattice constructions further\nmotivate the nonperturbative explorations of models inspired by technicolor,\norbifolding and orientifolding in string theories and the Corrigan-Ramond\nlimit."
    },
    {
        "anchor": "Low-mode deflation for twisted-mass and RHMC reweighting in lattice QCD: We propose improved estimators to compute the reweighting factors which are\nneeded for lattice QCD calculations that rely on twisted-mass reweighting for\nthe light quark contribution and the Rational Hybrid Monte Carlo (RHMC)\nalgorithm for non-degenerate quark masses. This is the case for a number of\nmodern large-scale simulations based on O(a) improved Wilson fermions. We find\na significant reduction of uncertainties for the reweighting factors at similar\ncomputational cost compared to the conventional estimation. This leads to a\nsignificant increase in precision for phenomenologically relevant observables\nwith high correlation to the low eigenmodes of the Wilson-Dirac operator in the\npresence of exceptionally small eigenvalues. Supplementary details regarding\nthe spectral gap of the light quark Dirac operator on the 2+1 flavor\nlarge-volume ensembles explored in this study can be found in an accompanying\nappendix.",
        "positive": "Thermodynamics of (2+1)-flavor QCD: We report on the status of our QCD thermodynamics project. It is performed on\nthe QCDOC machine at Brookhaven National Laboratory and the APEnext machine at\nBielefeld University. Using a 2+1 flavor formulation of QCD at almost realistic\nquark masses we calculated several thermodynamical quantities. In this\nproceeding we show the susceptibilites of the chiral condensate and the\nPolyakov loop, the static quark potential and the spatial string tension."
    },
    {
        "anchor": "Coulomb gauge gluon propagator and the Gribov formula: We analyze the lattice SU(2) Yang-Mills theory in Coulomb gauge. We show that\nthe static gluon propagator is multiplicative renormalizable and takes the\nsimple form $D(|\\vec{p}|)^{-1}=\\sqrt{|\\vec{p}|^2+M^4/|\\vec{p}|^2}$, proposed by\nGribov through heuristic arguments many years ago. We find $M=0.88(1) {\\rm GeV}\n\\simeq 2 \\sqrt{\\sigma}$.",
        "positive": "Magnetic susceptibility and equation of state of N_f = 2+1 QCD with\n  physical quark masses: We determine the free energy of strongly interacting matter as a function of\nan applied constant and uniform magnetic field. We consider N_f = 2+1 QCD with\nphysical quark masses, discretized on a lattice by stout improved staggered\nfermions and a tree level improved Symanzik pure gauge action, and explore\nthree different lattice spacings. For magnetic fields of the order of those\nproduced in non-central heavy ion collisions (eB ~ 0.1 GeV^2) strongly\ninteracting matter behaves like a medium with a linear response, and is\nparamagnetic both above and below the deconfinement transition, with a\nsusceptibility which steeply rises in the deconfined phase. We compute the\nequation of state, showing that the relative increase in the pressure due to\nthe magnetic field gets larger around the transition, and of the order of 10 %\nfor eB ~ 0.1 GeV^2."
    },
    {
        "anchor": "The hadronic vacuum polarization function with O(a)-improved Wilson\n  fermions - an update: We present an update of our lattice QCD study of the vacuum polarization\nfunction using O$(a)$-improved $N_ {\\rm f} =2$ Wilson fermions with increased\nstatistics and a large set of momenta. The resulting points are highly\ncorrelated and thus require a correlated fitting procedure. We employ an\nextended frequentist method to estimate the systematic uncertainties due to the\nmomentum dependence and to the continuum and chiral extrapolations. We present\npreliminary results of the leading order hadronic contribution of the anomalous\nmagnetic moment of the muon $\\left(a_\\mu^{\\mathrm{HLO}}\\right)$ at the physical\npoint for $u,d,s$ and $c$ valence quarks.",
        "positive": "Chiral gauged fermions on a lattice: The chiral fermion model with local multifermion interactions proposed in\nNucl. Phys. B486 (1997) 282 and Phys. Rev. D61 (2000) 054502 processes an exact\nSU_L(2) chiral gauge symmetry and SU_L(2) by U_R(1) chiral flavour symmetry on\na lattice and a plausible scaling region for the target chiral gauge theory in\nthe continuum limit. Following the previous analysis of massive and massless\nfermion spectra in the scaling region, we compute the coupling vertices between\ngauge field and fermions by the strong multifermion coupling expansion and\nanalytical continuation of these vertex functions in the energy-momentum space.\nWe show a peculiar scenario that a massless fermion is SU_L(2)-chirally gauged\nin the low energy and 15 non-degenerate massive Dirac fermions are\nSU_L(2)-vectorially gauged at the lattice scale O(1/a). The Ward identities\nassociated to the chiral gauge symmetry are realized by both the massless\nchiral fermion and massive Dirac fermions. These Ward identities protect the\nperturbative calculations in the small gauge coupling from hard gauge-symmetry\nbreakings and lead to the normal gauge-invariant renormalization prescription.\nThe vacuum functional is perturbatively computed by a continuum regularization\nscheme in 16 edges of Brillouin zones. We achieve the correct form of the gauge\nanomaly and U_L(1) fermion-flavour singlet anomaly with the soft chiral\nsymmetry breaking scale that is much smaller than the lattice scale. The\nresidual breakings of chiral gauge symmetry after the gauge anomaly\ncancellation are eliminated in the normal gauge-invarinant renormalization\nprescription. We discuss the consistency of the scenario and the reasons for it\nto work for perturbative and non-perturbative gauge field."
    },
    {
        "anchor": "Chiral magnetic effect in lattice QCD with a chiral chemical potential: We perform a first lattice QCD simulation including two-flavor dynamical\nfermion with a chiral chemical potential. Because the chiral chemical potential\ngives rise to no sign problem, we can exactly analyze a chirally imbalanced QCD\nmatter by the Monte Carlo simulation. By applying an external magnetic field to\nthis system, we obtain a finite induced current along the magnetic field, which\ncorresponds to the chiral magnetic effect. The obtained induced current is\nproportional to the magnetic field and to the chiral chemical potential, which\nis consistent with an analytical prediction.",
        "positive": "Supersphere non-linear sigma model on the lattice: Two-dimensional $O(N)$ non-linear sigma models are exactly solvable theories\nand have many applications, from statistical mechanics to their use as QCD toy\nmodels. We consider a supersymmetric extension, the non-linear sigma model on\nthe supersphere~$S^{N+2m-1|2m}\\equiv \\frac{OSP(N+2m|2m)}{OSP(N+2m-1|2m)}$. We\nbriefly describe its renormalization properties and lattice discretization, and\npresent a strategy for numerical simulations together with some preliminary\nnumerical results."
    },
    {
        "anchor": "Unquenched domain wall quarks with TSMB: The numerical simulation of domain wall quarks with the two-step multi-boson\n(TSMB) algorithm is investigated.\n  Tests are performed on a 8^3*4 lattice with N_f=2 quark flavours.",
        "positive": "Visualization of semileptonic form factors from lattice QCD: Comparisons of lattice-QCD calculations of semileptonic form factors with\nexperimental measurements often display two sets of points, one each for\nlattice QCD and experiment. Here we propose to display the output of a\nlattice-QCD analysis as a curve and error band. This is justified, because\nlattice-QCD results rely in part on fitting, both for the chiral extrapolation\nand to extend lattice-QCD data over the full physically allowed kinematic\ndomain. To display an error band, correlations in the fit parameters must be\ntaken into account. For the statistical error, the correlation comes from the\nfit. To illustrate how to address correlations in the systematic errors, we use\nthe Becirevic-Kaidalov parametrization of the D -> pi l nu and D -> K l nu form\nfactors, and a analyticity-based fit for the B -> pi l nu form factor f_+."
    },
    {
        "anchor": "Towards flavour diffusion coefficient and electrical conductivity\n  without ultraviolet contamination: By subtracting from a recent lattice measurement of the thermal\nvector-current correlator the known 5-loop vacuum contribution, we demonstrate\nthat the remainder is small and shows no visible short-distance divergence. It\ncan therefore in principle be subjected to model-independent analytic\ncontinuation. Testing a particular implementation, we obtain estimates for the\nflavour-diffusion coefficient (2 pi T D \\gsim 0.8) and electrical conductivity\nwhich are significantly smaller than previous results. Although systematic\nerrors remain beyond control at present, some aspects of our approach could be\nof a wider applicability.",
        "positive": "Calculating the running coupling in strong electroweak models: One possibility for Beyond Standard Model physics is a new\nstrongly-interacting gauge theory. One way to determine if a non-abelian gauge\ntheory is QCD-like or conformal is to measure the running of the renormalized\ngauge coupling. We define the renormalized coupling from Wilson loop ratios,\nand measure these ratios via lattice simulations. We test this method in SU(3)\npure gauge theory and show some first results for simulations with dynamical\nfermions in the fundamental representation."
    },
    {
        "anchor": "Gauge invariant field strength correlators from RG smoothing and color\n  correlations between topological charge clusters: Using the renormalization group based smoothing technique we have studied the\ngauge invariant field strength correlator at T\\ne0 and T=0 in pure SU(2) gauge\ntheory. In conjunction with a cluster analysis, the field strength correlator\nis used to study correlations between the clusters in space and color\norientation.",
        "positive": "Pure-gauge SU(2) on large lattices: We have calculated the $q\\bar q$ potential over a wide range of lattice\nseparations on a $48^3\\cdot56$ lattice at $\\beta = 2.85$. We are able to\ninvestigate both long-range and (by correcting for the effects of lack of\nrotational invariance) short-range potentials. From the former we estimate the\nstring tension and from the latter we are able to investigate asymptotic\nscaling. Fitting to this enables us to give an estimate for the\n$\\Lambda$-parameter of pure-gauge SU(2)."
    },
    {
        "anchor": "QED corrections to leptonic decay rates: RBC/UKQCD is preparing a calculation of leptonic decay rates including\nisospin breaking corrections using a perturbative approach to include NLO\ncontributions from QED effects. We present preliminary numerical results for a\ncontribution to the leptonic pion decay rate and report on exploratory studies\nof computational techniques based on all-to-all propagators.",
        "positive": "Lattice simulations of Born-Infeld non-linear QED: Born-Infeld non-linear electrodynamics was introduced to render the self\nenergy of a point particle finite. It has recently been revived as a field\ntheory for branes and strings. We quantize this theory on a Euclidean\nspace-time lattice, using Metropolis Monte-Carlo simulations to measure the\nproperties of the quantum field theory. Luscher-Weisz methods are used to\nmeasure the electromagnetic fields from a static point charge. The D field from\na point charge appears to be identical to that for the normal Maxwell\nLagrangian. The E field is enhanced by quantum fluctuations, and shows short\ndistance screening as it does in the classical theory."
    },
    {
        "anchor": "Parton Distribution Functions with Twisted Mass Fermions: We present a first Wilson twisted mass fermion calculation of the matrix\nelement between pion states of the twist-2 operator, which is related to the\nthe lowest moment < x > of the valence quark parton distribution function in a\npion. Using Wilson twisted mass fermions in the quenched approximation we\ndemonstrate that < x > can be computed at small pseudoscalar meson masses down\nto values of order 250 MeV. We investigate the scaling behaviour of this\nphysically important quantity by applying two definitions of the critical mass\nand observe a scaling compatible with the expected O(a^2) behaviour in both\ncases. A combined continuum extrapolation allows to obtain reliable results for\n< x > at very small pseudoscalar meson masses, which previously could not be\nexplored by lattice QCD simulations.",
        "positive": "Glue Ball Masses and the Chameleon Gauge: We introduce a new numerical technique to compute mass spectra, based on\ndifference method and on a new gauge fixing procedure. We show that the method\nis very effective by test runs on a $SU(2)$ lattice gauge theory."
    },
    {
        "anchor": "Strong coupling constant and heavy quark masses in 2+1 flavor QCD: We present a determination of the strong coupling constant and heavy quark\nmasses in (2+1)-flavor QCD using lattice calculations of the moments of the\npseudo-scalar quarkonium correlators at several values of the heavy valence\nquark mass with Highly Improved Staggered Quark (HISQ) action. We determine the\nstrong coupling constant in the $\\overline{MS}$ scheme at four low-energy\nscales corresponding to $m_c$, $1.5m_c$, $2m_c$, and $3m_c$, with $m_c$ being\nthe charm quark mass. The novel feature of our analysis that up to eleven\nlattice spacings are used in the continuum extrapolations, with the smallest\nlattice spacing being $0.025$ fm. We obtain\n$\\Lambda_{\\overline{MS}}^{n_f=3}=298 \\pm 16$ MeV, which is equivalent to\n$\\alpha_s(\\mu=M_Z,n_f=5)=0.1159(12)$. For the charm and bottom quark masses in\nthe $\\overline{MS}$ scheme, we obtain: $m_c(\\mu=m_c,n_f=4)=1.265(10)$ GeV and\n$m_b(\\mu=m_b,n_f=5)=4.188(37)$ GeV.",
        "positive": "The MSSM Electroweak Phase Transition on the Lattice: We study the MSSM finite temperature electroweak phase transition with\nlattice Monte Carlo simulations, for a large Higgs mass (m_H ~ 95 GeV) and\nlight stop masses (m_tR ~ 150...160 GeV). We employ a 3d effective field theory\napproach, where the degrees of freedom appearing in the action are the SU(2)\nand SU(3) gauge fields, the weakly interacting Higgs doublet, and the strongly\ninteracting stop triplet. We determine the phase diagram, the critical\ntemperatures, the scalar field expectation values, the latent heat, the\ninterface tension and the correlation lengths at the phase transition points.\nExtrapolating the results to the infinite volume and continuum limits, we find\nthat the transition is stronger than indicated by 2-loop perturbation theory,\nguaranteeing that the MSSM phase transition is strong enough for baryogenesis\nin this regime. We also study the possibility of a two-stage phase transition,\nin which the stop field gets an expectation value in an intermediate phase. We\nfind that a two-stage transition exists non-perturbatively, as well, but for\nsomewhat smaller stop masses than in perturbation theory. Finally, the latter\nstage of the two-stage transition is found to be extremely strong, and thus it\nmight not be allowed in the cosmological environment."
    },
    {
        "anchor": "Curvature of the pseudocritical line in (2+1)-flavor QCD with HISQ\n  fermions: We study QCD with (2+1)-HISQ fermions at nonzero temperature and nonzero\nimaginary baryon chemical potential. Monte Carlo simulations are performed\nusing the MILC code along the line of constant physics with a light to strange\nmass ratio of $m_l/m_s=1/20$ on lattices up to $48^3 \\times 12$ to check for\nfinite cutoff effects. We determine the curvature of the pseudocritical line\nextrapolated to the continuum limit.",
        "positive": "Do we understand the unquenched value of fB?: I review our qualitative understanding of the increase in the value of the B\nmeson decay constant (fB), when dynamical fermions are included in lattice QCD\ncalculations."
    },
    {
        "anchor": "$D \\rightarrow K, l \u03bd$ Semileptonic Decay Scalar Form Factor and\n  $|V_{cs}|$ from Lattice QCD: We present a new study of D semileptonic decays on the lattice which employs\nthe Highly Improved Staggered Quark (HISQ) action for both the charm and the\nlight valence quarks. We work with MILC unquenched $N_f = 2 + 1$ lattices and\ndetermine the scalar form factor $f_0(q^2)$ for $D \\rightarrow K, l \\nu$\nsemileptonic decays. The form factor is obtained from a scalar current matrix\nelement that does not require any operator matching. We develop a new approach\nto carrying out chiral/continuum extrapolations of $f_0(q^2)$. The method uses\nthe kinematic \"$z$\" variable instead of $q^2$ or the kaon energy $E_K$ and is\napplicable over the entire physical $q^2$ range. We find $f^{D \\rightarrow\nK}_0(0) \\equiv f^{D \\rightarrow K}_+(0) = 0.747(19)$ in the chiral plus\ncontinuum limit and hereby improve the theory error on this quantity by a\nfactor of $\\sim$4 compared to previous lattice determinations. Combining the\nnew theory result with recent experimental measurements of the product $f^{D\n\\rightarrow K}_+(0) * |V_{cs}| $ from BaBar and CLEO-c leads to the most\nprecise direct determination of the CKM matrix element $|V_{cs}| $ to date,\n$|V_{cs}| = 0.961(11)(24)$, where the first error comes from experiment and the\nsecond is the lattice QCD theory error. We calculate the ratio $f^{D\n\\rightarrow K}_+(0)/f_{D_s}$ and find $2.986 \\pm 0.087$ GeV$^{-1}$ and show\nthat this agrees with experiment.",
        "positive": "Wilson loop distributions, higher representations and centre dominance\n  in SU(2): To help understand the centre dominance picture of confinement, we look at\nWilson loop distributions in pure SU(2) lattice gauge theory. A strong coupling\napproximation for the distribution is developed to use for comparisons. We\nperform a Fourier expansion of the distribution: centre dominance here\ncorresponds to suppression of odd terms beyond the first. The Fourier terms\ncorrespond to SU(2) representations; hence Casimir scaling behaviour leads to\ncentre dominance. We examine the positive plaquette model, where only thick\nvortices are present. We show that a simple picture of random, non-interacting\ncentre vortices gives a string tension about 3/4 of the measured value.\nFinally, we attempt to limit confusion about the adjoint representation."
    },
    {
        "anchor": "Topological susceptibility and string tension in the lattice CP(N)\n  models: In the lattice CP(N) models we studied the problems related to the measure of\nthe topological susceptibility and the string tension . We perfomed numerical\nsimulations at N=4 and N=10. In order to test the universality, we adopted two\ndifferent lattice formulations. Scaling and universality tests led to the\nconclusion that at N=10 the geometrical approach gives a good definition of\nlattice topological susceptibility. On the other hand, N=4 proved not to be\nlarge enough to suppress the unphysical configurations, called dislocations,\ncontributing to the topological susceptibility. We obtained other\ndeterminations of the topological susceptibility by the field theoretical\nmethod, wich relies on a local definition of the lattice topological charge\ndensity, and the cooling method. They gave quite consistent results, showing\nscaling and universality. The large-N expansion predicts an exponential area\nlaw behavior for sufficiently large Wilson loops, which implies confinement,\ndue to the dynamical matter fields and absence of the screening phenomenon. We\ndetermined the string tension, without finding evidence of screening effects.",
        "positive": "The anti-quark--quark potential from Bethe-Salpeter amplitudes on\n  lattice: Potentials of quark--anti-quark pairs are studied from the anti-q--q\nNambu-Bethe-Salpeter (NBS) wave functions in quenched lattice QCD. With the use\nof a method which has been recently developed in the derivation of nuclear\nforces from QCD, we derive the anti-q--q potentials with finite quark masses\nfrom the NBS wave functions. We calculate the anti-q--q NBS wave functions in\npseudo-scalar and vector channels for several quark masses. The derived\npotentials in both channels reveal linear confinement plus Coulomb potentials.\nWe also discuss the quark-mass and channel dependence of the anti-q--q\npotentials."
    },
    {
        "anchor": "Jet transport coefficient $\\hat{q}$ in lattice QCD: We present the first calculation of the jet transport coefficient $\\hat{q}$\nin quenched and (2+1)-flavor QCD on a 4-D Euclidean lattice. The light-like\npropagation of an energetic parton is factorized from the mean square gain in\nmomentum transverse to the direction of propagation, which is expressed in\nterms of the thermal field-strength field-strength correlator. The\nleading-twist term in its operator product expansion is calculated on the\nlattice. Continuum extrapolated quenched results, and full QCD estimates based\non un-renormalized lattice data, over multiple lattice sizes, are compared with\n(non) perturbative calculations and phenomenological extractions of $\\hat{q}$.\nThe lattice data for $\\hat{q}$ show a temperature dependence similar to the\nentropy density. Within uncertainties, these are consistent with\nphenomenological extractions, contrary to calculations using perturbation\ntheory.",
        "positive": "Time Dependence of Nucleon Correlation Functions in Chiral Perturbation\n  Theory: We consider corrections to nucleon correlation functions arising from times\nthat are far from the asymptotic limit. For such times, the single nucleon\nstate is contaminated by the pion-nucleon and pion-delta continuum. We use\nheavy baryon chiral perturbation theory to derive the spectral representation\nof the nucleon two-point function. Finite time corrections to the axial current\ncorrelation function are also derived. Pion-nucleon excited state contributions\ndrive the axial correlator upward, while contributions from the interference of\npion-delta and pion-nucleon states drive the axial correlator downward. Our\nresults can be compared qualitatively to optimized nucleon correlators\ncalculated in lattice QCD, because the chiral corrections characterize only\nlow-energy excitations above the ground state. We show that improved nucleon\noperators can lead to an underestimation of the nucleon axial charge."
    },
    {
        "anchor": "Classification of Minimally Doubled Fermions: We propose a method to control the number of species of lattice fermions\nwhich yields new classes of minimally doubled lattice fermions. We show it is\npossible to control the number of species by handling $O(a)$ Wilson-term-like\ncorrections in fermion actions, which we will term ``Twisted-ordering Method\".\nUsing this method we obtain new minimally doubled actions with one exact chiral\nsymmetry and exact locality. We classify the known minimally doubled fermions\ninto two types based on the locations of the propagator poles in the Brillouin\nzone.",
        "positive": "Scattering phases for meson and baryon resonances on general\n  moving-frame lattices: A proposal by L\\\"uscher enables one to compute the scattering phases of\nelastic two-body systems from the energy levels of the lattice Hamiltonian in a\nfinite volume. In this work we generalize the formalism to S--, P-- and D--wave\nmeson and baryon resonances, and general total momenta. Employing nonvanishing\nmomenta has several advantages, among them making a wider range of energy\nlevels accessible on a single lattice volume and shifting the level crossing to\nsmaller values of $m_\\pi L$."
    },
    {
        "anchor": "I=2 Two-Pion Wave Function and Scattering Phase Shift: We calculate a two-pion wave function for the I=2 $S$-wave two-pion system\nwith a finite scattering momentum and estimate the interaction range between\ntwo pions, which allows us to examine the validity of a necessary condition for\nthe finite size formula presented by Rummukainen and Gottlieb. We work in the\nquenched approximation employing the plaquette gauge action for gluons and the\nimproved Wilson action for quarks at $1/a=1.63 {\\rm GeV}$ on $32^3\\times 120$\nlattice. The quark masses are chosen to give $m_\\pi = 0.420$, 0.488 and $0.587\n{\\rm GeV}$. We find that the energy dependence of the interaction range is\nsmall and the necessary condition is satisfied for our range of the quark mass\nand the scattering momentum, $k \\le 0.16 {\\rm GeV}$. We also find that the\nscattering phase shift can be obtained with a smaller statistical error from\nthe two-pion wave function than from the two-pion time correlator.",
        "positive": "SU(4) pure-gauge string tensions: In response to recently renewed interests in SU(N) pure-gauge dynamics with\nlarge N, both from M/string duality and from finite-temperature QCD phase\nstructure, we calculate string tensions acting between the fundamental 4,\ndiquark 6 and other color charges in SU(4) pure-gauge theory at temperatures\nbelow the deconfining phase change and above the bulk phase transition. Our\nresults suggest 4 and 6 representations have different string tensions, with a\nratio of about 1.3. We also found the deconfining phase change is not strong."
    },
    {
        "anchor": "Correlations for non-Hermitian Dirac operators: chemical potential in\n  three-dimensional QCD: In the presence of a non-vanishing chemical potential the eigenvalues of the\nDirac operator become complex. We use a random matrix model approach to\ncalculate analytically all correlation functions at weak and strong\nnon-Hermiticity for three-dimensional QCD with broken flavor symmetry and\nfour-dimensional QCD in the bulk.",
        "positive": "Correlation functions and critical behaviour on fluctuating geometries: We study the two-point correlation function in the model of branched polymers\nand its relation to the critical behaviour of the model. We show that the\ncorrelation function has a universal scaling form in the generic phase with the\nonly scale given by the size of the polymer. We show that the origin of the\nsingularity of the free energy at the critical point is different from that in\nthe standard statistical models. The transition is related to the change of the\ndimensionality of the system."
    },
    {
        "anchor": "Lattice QCD with two light Wilson quarks and maximally twisted mass: We summarise status and recent results of the European Twisted Mass\ncollaboration (ETMC). The collaboration has generated gauge configurations for\nthree different values of the lattice spacing smaller or equal 0.1 fm and\nvalues of the charged pseudo scalar mass as low as 300 MeV with two flavours of\nmaximally twisted mass quarks. We provide evidence that O(a) improvement works\nvery well with maximally twisted mass fermions and that also higher order\nlattice artifacts appear to be small. The currently only quantity in the light\nmeson and baryon sector where cut-off effects are visible is the neutral pseudo\nscalar meson mass and we present an attempt to understand this from a\ntheoretical point of view.\n  We describe finite size effects and quark mass dependence of the mass and\ndecay constant of the (charged) pseudo scalar meson with chiral perturbation\ntheory formulae and our current estimate for the low energy constants l_{3,4}\nis l_3=3.44(8)(35) and l_4=4.61(4)(11). Results for the average up-down, the\nstrange and the charm quark mass and the chiral condensate are also presented.",
        "positive": "Performance of the GPU inverters with Chroma+QUDA for various fermion\n  actions: We present our progress on the Chroma interfaces of the twisted-mass, HISQ\n(highly improved staggered quark) and overlap fermion inverters using QUDA."
    },
    {
        "anchor": "Vortex dominance of the 0+ and 2+ glueball mass in SU(2) lattice gauge\n  theory: The c-vortex ensembles are constructed by means of the recently proposed\ncooling method which gradually removes the SU(2)/Z_2 coset fields from the\nSU(2) lattice configurations and which thus reveals the Z_2 vortex vacuum\ntexture. Using Teper's blocking method, the screening masses of the 0+ and the\n2+ glueball is calculated from these vortex ensembles and compared with the\nmasses obtained from full configurations. The masses of either case agree\nwithin the achieved numerical accuracy of 10%. As a byproduct, we find that the\noverlaps of the Teper operators with the glueball wavefunctions are\nsignificantly larger in the case of the c-vortex ensembles.",
        "positive": "Steiner Variations on Random Surfaces: Ambartzumian et.al. suggested that the modified Steiner action functional had\ndesirable properties for a random surface action. However, Durhuus and Jonsson\npointed out that such an action led to an ill-defined grand-canonical partition\nfunction and suggested that the addition of an area term might improve matters.\nIn this paper we investigate this and other related actions numerically for\ndynamically triangulated random surfaces and compare the results with the\ngaussian plus extrinsic curvature actions that have been used previously."
    },
    {
        "anchor": "Resonances in Coupled-Channel Scattering: Excited hadrons are seen as resonances in the scattering of lighter stable\nhadrons like $\\pi$, $K$ and $\\eta$. Many decay into multiple final states\nnecessitating coupled-channel analyses. Recently it has become possible to\nobtain coupled-channel scattering amplitudes from lattice QCD. Using large\ndiverse bases of operators it is possible to obtain reliable finite volume\nspectra at energies where multiple channels are open. Utilising the finite\nvolume formalism proposed by L\\\"uscher and extended by several others,\nscattering amplitudes can be extracted from the finite volume spectra. Recent\napplications will be discussed where the energy dependence of scattering\namplitudes is mapped out in several quantum numbers. These are then continued\nto complex energies to extract resonance poles and couplings.",
        "positive": "Two-dimensional $\\mathcal{N}=2$ Super-Yang-Mills Theory: Supersymmetry is one of the possible scenarios for physics beyond the\nstandard model. The building blocks of this scenario are supersymmetric gauge\ntheories. In our work we study the $\\mathcal{N}=1$ Super-Yang-Mills (SYM)\ntheory with gauge group SU(2) dimensionally reduced to two-dimensional\n$\\mathcal{N}=2$ SYM theory. In our lattice formulation we break supersymmetry\nand chiral symmetry explicitly while preserving R symmetry. By fine tuning the\nbar-mass of the fermions in the Lagrangian we construct a supersymmetric\ncontinuum theory. To this aim we carefully investigate mass spectra and Ward\nidentities, which both show a clear signal of supersymmetry restoration in the\ncontinuum limit."
    },
    {
        "anchor": "Reweighting twisted boundary conditions: Imposing twisted boundary conditions on the fermionic fields is a procedure\nextensively used when evaluating, for example, form factors on the lattice.\nTwisting is usually performed for one flavour and only in the valence, and this\ncauses a breaking of unitarity. In this work we explore the possibility of\nrestoring unitarity through the reweighting method. We first study some\nproperties of the approach at tree level and then we stochastically evaluate\nratios of fermionic determinants for different boundary conditions in order to\ninclude them in the gauge averages, avoiding in this way the expensive\ngeneration of new configurations for each choice of the twisting angle,\n$\\theta$. As expected the effect of reweighting is negligible in the case of\nlarge volumes but it is important when the volumes are small and the twisting\nangles are large. In particular we find a measurable effect for the plaquette\nand the pion correlation function in the case of $\\theta=\\pi/2$ in a volume\n$16\\times 8^3$, and we observe a systematic upward shift in the pion dispersion\nrelation.",
        "positive": "Matrix elements of bound states in a finite volume: Recently, a framework was developed for studying form factors of two-body\nstates probed with an external current. Finite volume matrix elements that may\nbe computed via lattice QCD are converted to infinite volume generalized form\nfactors. These generalized form factors allow us to study the structure of\ncomposite states. In this talk, we consider the application of this formalism\nto bound states, and compare the leading finite volume effects to the general\nresults of the framework. Specifically, we consider the implications for the\ndeuteron at the physical point, and conclude that it's necessary to use the\nfull formalism to not be saturated by systematics"
    },
    {
        "anchor": "Lattice QCD and Baryon-Baryon Interactions: In this chapter, the current status on baryon-baryon interactions such as\nnuclear forces in lattice Quantum ChromoDynamics (QCD) is reviewed. In studies\nof baryon-baryon interactions in lattice QCD, the most reliable method so far\nis the potential method, proposed by the Hadrons to Atomic nuclei from Lattice\nQCD (HAL QCD) collaboration, whose formulation, properties and extensions are\nexplained in detail. Using the HAL QCD potential method, potentials between\nnucleons (proton and neutron, denoted by $N$) in the derivative expansion have\nbeen extracted in various cases. The lattice QCD results shown in this chapter\ninclude a Leading Order (LO) central potential in the parity-even $NN(^1S_0)$\nchannel, LO central and tensor potentials in the parity-even\n$NN(^3S_1$-$^3D_1)$ channel, and a Next-to-Leading Order (NLO) spin-orbit\npotential as well as LO potentials in the parity-odd channels. Preliminary\nresults at the almost physical pion and kaon masses, in addition to exploratory\nstudies on three-nucleon potentials, are presented. Interactions between\ngeneric baryons including hyperons, made of one or more strange quarks as well\nas up and down quarks, have also been investigated. Universal properties of\npotentials between baryons become manifest in the flavor SU(3) symmetric limit,\nwhere masses of three quarks, up, down and strange, are all equal. In\nparticular, it is observed that one bound state, traditionally called the\n$H$-dibaryon, appears in the flavor singlet representation of SU(3). A fate of\nthe $H$ dibaryon is also discussed with flavor SU(3) breaking taken into\naccount at the almost physical point. Finally, various kinds of dibaryons,\nbound or resonate states of two baryons, including charmed dibaryons, have been\npredicted by lattice QCD simulations at the almost physical point.",
        "positive": "Can a Logarithmically Running Coupling Mimic a String Tension?: It is shown that a Coulomb potential using a running coupling slightly\nmodified from the perturbative form can produce an interquark potential that\nappears nearly linear over a large distance range. Recent high-statistics SU(2)\nlattice gauge theory data fit well to this potential without the need for a\nlinear string-tension term. This calls into question the accuracy of string\ntension measurements which are based on the assumption of a constant\ncoefficient for the Coulomb term. It also opens up the possibility of obtaining\nan effectively confining potential from gluon exchange alone."
    },
    {
        "anchor": "A surprise with many-flavor staggered fermions in the strong coupling\n  limit: It is widely believed that chiral symmetry is spontaneously broken at zero\ntemperature in the strong coupling limit of staggered fermions, for any number\nof colors and flavors. Using Monte Carlo simulations, we show that this\nconventional wisdom, based on a mean-field analysis, is wrong. For sufficiently\nmany fundamental flavors, chiral symmetry is restored via a bulk, first-order\ntransition. This chirally symmetric phase appears to be analytically connected\nwith the expected conformal window of many-flavor continuum QCD. We perform\nsimulations in the chirally symmetric phase at zero quark mass for various\nsystem sizes L, and measure the torelon mass and the Dirac spectrum. We find\nthat all observables scale with L, which is hence the only infrared length\nscale. Thus, the strong-coupling chirally restored phase appears as a\nconvenient laboratory to study IR-conformality. Finally, we present a\nconjecture for the phase diagram of lattice QCD as a function of the bare\ncoupling and the number of quark flavors.",
        "positive": "Probing the chiral regime of Nf=2 QCD with mixed actions: We report on our first experiences with a mixed action setup with overlap\nvalence quarks and non-perturbatively O(a) improved Wilson sea quarks. For the\nlatter we employ CLS Nf=2 configurations with light sea quark masses at small\nlattice spacings. Exact chiral symmetry allows to consider very light valence\nquarks and explore the matching to (partially quenched) Chiral Perturbation\nTheory (ChPT) in a mixed epsilon/p-regime. We compute the topological\nsusceptibility and the low-lying spectrum of the massless Neuberger-Dirac\noperator for three values of the sea quark mass, and compare the sea quark mass\ndependence to NLO ChPT in the mixed regime. This provides two different\ndeterminations of the chiral condensate, as well as information about some NLO\nlow-energy couplings. Our results allow to test the consistency of the\nmixed-regime approach to ChPT, as well as of the mixed action framework."
    },
    {
        "anchor": "Can Lorentz-breaking fermionic condensates form in large N\n  strongly-coupled Lattice Gauge Theories?: The possibility of Lorentz symmetry breaking (LSB) has attracted considerable\nattention in recent years for a variety of reasons, including the attractive\nprospect of the graviton as a Goldstone boson. Though a number of effective\nfield theory analyses of such phenomena have recently been given it remains an\nopen question whether they can take place in an underlying UV complete theory.\nHere we consider the question of LSB in large N lattice gauge theories in the\nstrong coupling limit. We apply techniques that have previously been used to\ncorrectly predict the formation of chiral symmetry breaking condensates in this\nlimit. Generalizing such methods to other composite operators we find that\ncertain LSB condensates can indeed form. In addition, the interesting\npossibility arises of condensates that 'lock' internal with external\nsymmetries.",
        "positive": "Pion couplings to the scalar B meson: We present two-flavor lattice QCD estimates of the hadronic couplings\n$g_{B^*_0 B \\pi}$ and $g_{B_1^* B_0^* \\pi}$ that parametrise the non leptonic\ndecays $B^*_0 \\to B \\pi$ and $B^*_1 \\to B_0^* \\pi$. We use CLS two-flavour\ngauge ensembles. Our framework is the Heavy Quark Effective Theory (HQET) in\nthe static limit and solving a Generalized Eigenvalue Problem (GEVP) reveals\ncrucial to disentangle the $B^*_0$($B^*_1$) state from the $B \\pi$($B^*\\pi$)\nstate. This work brings us some experience on how to treat the possible\ncontribution from multihadronic states to correlation functions calculated on\nthe lattice, especially when $S$-wave states are involved."
    },
    {
        "anchor": "The random lattice as a regularization scheme: A semi-analytic method to compute the first coefficients of the\nrenormalization group functions on a random lattice is introduced. It is used\nto show that the two-dimensional $O(N)$ non-linear $\\sigma$-model regularized\non a random lattice has the correct continuum limit. A degree $\\kappa$ of\n``randomness'' in the lattice is introduced and an estimate of the ratio\n$\\Lambda_{random}/\\Lambda_{regular}$ for two rather opposite values of $\\kappa$\nin the $\\sigma$-model is also given. This ratio turns out to depend on\n$\\kappa$.",
        "positive": "Quark Confinement in Multi-Flavor Quantum Chromodynamics: It is investigated how quark confinement depends on the number of flavors,\n$N_f$, in QCD on the lattice with Wilson quarks. We strengthen and extend the\nconclusion reported at {\\it Lattice 91}: (1) For $N_f \\le 6$ the finite\ntemperature deconfining transition/crossover line crosses the chiral limit at\nfinite $\\beta$. We identify the crossing point for $N_f=2$ and 6 on a $T=4$\nlattice, where $T$ is the lattice size in the temporal direction. We find the\nphase transition at the crossing point is continuous for $N_f=2$, while it is\nof first order for $N_f=6$. (2) For $N_f \\ge 7$, the $T$-independent\ndeconfining transition observed at $\\beta=0$ extends up to $\\beta=4.5$ with the\ncritical quark mass $m_{\\rm quark} = O(a^{-1})$, where $a$ is the lattice\nspacing."
    },
    {
        "anchor": "Eigenvalue-flipping Algorithm for Matrix Monte Carlo: Many physical systems can be described in terms of matrix models that we\noften cannot solve analytically. Fortunately, they can be studied numerically\nin a straightforward way. Many commonly used algorithms follow the Monte Carlo\nmethod, which is efficient for small matrix sizes but cannot guarantee\nergodicity when working with large ones. In this paper, we propose an\nimprovement of the algorithm that, for a large class of matrix models, allows\nto tunnel between various vacua in a proficient way, where sign change of\neigenvalues is proposed externally. We test the method on two models: the pure\npotential matrix model and the scalar field theory on the fuzzy sphere.",
        "positive": "Hot electroweak matter: This talk summarises recent results on lattice Monte Carlo studies of finite\nT electroweak phase transition. Particular attention is given to the 3d\neffective theory approach, replacing the full 4d theory by a three dimensional\neffective theory of the modes constant in imaginary time."
    },
    {
        "anchor": "Mesons upon low-lying Dirac mode exclusion: We study the isoscalar and isovector $J=0,1$ mesons with the overlap operator\nwithin two flavour lattice QCD. After subtraction of the lowest-lying Dirac\neigenmodes from the valence quark propagator all disconnected contributions\nvanish and all possible point-to-point $J=0$ correlators become identical,\nsignaling a simultaneous restoration of both $SU(2)_L \\times SU(2)_R$ and\n$U(1)_A$ symmetries. The ground states of the $\\pi,\\sigma,a_0,\\eta$ mesons do\nnot survive this truncation. All possible $J=1$ states have a very clean\nexponential decay and become degenerate, demonstrating a $SU(4)$ symmetry of a\ndynamical QCD-like string.",
        "positive": "Nonperturbative Gauge Fixing and Perturbation Theory: We compare the gauge-fixing approach proposed by Jona-Lasinio and Parrinello,\nand by Zwanziger (JPLZ) with the standard Fadeev-Popov procedure, and\ndemonstrate perturbative equality of gauge-invariant quantities, up to\nirrelevant terms induced by the cutoff. We also show how a set of local,\nrenormalizable Feynman rules can be constructed for the JPLZ procedure."
    },
    {
        "anchor": "Architectural choices for the Columbia 0.8 Teraflops machine: We discuss the hardware design choices made in our 16K-node 0.8 Teraflops\nsupercomputer project, a machine architecture optimized for full QCD\ncalculations. The efficiency of the conjugate gradient algorithm in terms of\nbalance of floating-point operations, memory handling and utilization, and\ncommunication overhead is addressed. We also discuss the technological\ninnovations and software tools that facilitate hardware design and what\nopportunities these give to the academic community.",
        "positive": "Confinement/deconfinement phase transition in SU(3) Yang-Mills theory in\n  view of dual superconductivity: In the preceeding works, we have given a non-Abelian dual superconductivity\npicture for quark confinement, and demonstrated the numerical evidences on the\nlattice. In this talk, we discuss the confinement and deconfinement phase\ntransition at finite temperature in view of the dual superconductivity. We\ninvestigate chromomagnetic monopole currents induced by chromoelectric flux in\nboth confinement and deconfinement phase by the numerical simulations on a\nlattice at finite temperature, and discuss the role of the chromomagnetic\nmonopole in the confinement/deconfinement phase transition."
    },
    {
        "anchor": "Lattice measurement of \u03b1_s with a realistic charm quark: We report on an estimate of \\alpha_s, renormalised in the MSbar scheme at the\ntau and Z^0 mass scales, by means of lattice QCD. Our major improvement\ncompared to previous lattice calculations is that, for the first time, no\nperturbative treatment at the charm threshold has been required since we have\nused statistical samples of gluon fields built by incorporating the vacuum\npolarisation effects of u/d, s and c sea quarks. Extracting \\alpha_s in the\nTaylor scheme from the lattice measurement of the ghost-ghost-gluon vertex, we\nobtain \\alpha_s^{MSbar}(m^2_Z)=0.1200(14) and\n\\alpha_s^{MSbar}(m^2_tau)=0.339(13).",
        "positive": "Bosonization and the lattice Gross-Neveu model: We consider a lattice version of the bosonized Gross-Neveu model. It is\nexplicitely chiral symmetric and its numerical simulation does not involve any\nanticommuting field. We study its non trivial $1/N$ expansion up to the\nnext-to-leading term comparing the results with explicit numerical simulations."
    },
    {
        "anchor": "Charm Quarks and the QCD Equation of State: We present a study of the effect of charm quarks on the QCD equation of state\nusing partially-quenched p4 charm quarks on a dynamically generated 2+1 flavor\nbackground, at zero chemical potential. We show preliminary results for the\ncharm quark contribution to the energy density and pressure in the high\ntemperature region ($T_c < T < 4 T_c$) and compare it to the free-field\ncalculation. The charm quark mass is determined by measuring the charmonium\nspectrum.",
        "positive": "Unquenched complex Dirac spectra at nonzero chemical potential:\n  two-colour QCD lattice data versus matrix model: We compare analytic predictions of non-Hermitian chiral random matrix theory\nwith the complex Dirac operator eigenvalue spectrum of two-colour lattice gauge\ntheory with dynamical fermions at nonzero chemical potential. The Dirac\neigenvalues come in complex conjugate pairs, making the action of this theory\nreal, and positive for our choice of two staggered flavours. This enables us to\nuse standard Monte-Carlo in testing the influence of chemical potential and\nquark mass on complex eigenvalues close to the origin. We find an excellent\nagreement between the analytic predictions and our data for two different\nvolumes over a range of chemical potentials below the chiral phase transition.\nIn particular we detect the effect of unquenching when going to very small\nquark masses."
    },
    {
        "anchor": "QCD string from D0 branes: We report the results of a set of high precision simulations performed in the\n3d gauge Ising model. We evaluated the interquark potential and the first few\nenergy levels and compared them with the predictions obtained with the\neffective Nambu-Goto string and with the free bosonic string. The data are\nprecise enough to unambiguously distinguish between the free string predictions\nand those obtained using the N-G effective string. At large distances we find a\nremarkable agreement between Monte Carlo data and N-G predictions for the first\nexcited energy level, while the free string picture is definitely excluded. As\nthe interquark distance is decreased (and/or the finite temperature becomes\nhigher) the Monte Carlo results show larger and larger deviations both from the\nN-G and from the free string predictions. In order to better understand this\nbehaviour we re-derived the effective Nambu-Goto theory result for the Polyakov\nloop correlator using a covariant quantization. We chose as boundary conditions\nthose of an open string attached to two D0-branes at spatial distance $R$, in a\ntarget space with compact euclidean time. Obviously our treatment is fully\nconsistent only in $d=26$. The extension to generic $d$ requires taking into\naccount the Liouville mode of Polyakov's formulation. The analogy with the\nstandard light cone calculation suggests that the contribution due to the\nLiouville field can be neglected for large $R$. At shorter scales, the\nLiouville mode cannot be neglected and its contribution to the interquark\npotential might be the source of the discrepancies with respect to the\neffective N-G results that we observe in our Monte Carlo simulations.",
        "positive": "Masses and decay constants of the $\u03b7$ and $\u03b7^\\prime$ mesons from\n  lattice QCD: We determine the masses, the singlet and octet decay constants as well as the\nanomalous matrix elements of the $\\eta$ and $\\eta^\\prime$ mesons in $N_f=2+1$\nQCD\\@. The results are obtained using twenty-one CLS ensembles of\nnon-perturbatively improved Wilson fermions that span four lattice spacings\nranging from $a\\approx 0.086\\,$fm down to $a\\approx 0.050\\,$fm. The pion masses\nvary from $M_{\\pi}=420\\,$MeV to $126\\,$MeV and the spatial lattice extents\n$L_s$ are such that $L_sM_\\pi\\gtrsim 4$, avoiding significant finite volume\neffects. The quark mass dependence of the data is tightly constrained by\nemploying two trajectories in the quark mass plane, enabling a thorough\ninvestigation of U($3$) large-$N_c$ chiral perturbation theory (ChPT). The\ncontinuum limit extrapolated data turn out to be reasonably well described by\nthe next-to-leading order ChPT parametrization and the respective low energy\nconstants are determined. The data are shown to be consistent with the singlet\naxial Ward identity and, for the first time, also the matrix elements with the\ntopological charge density are computed. We also derive the corresponding\nnext-to-leading order large-$N_{c}$ ChPT formulae. We find $F^8 =\n115.0(2.8)~\\text{MeV}$, $\\theta_{8} = -25.8(2.3)^{\\circ}$, $\\theta_0 =\n-8.1(1.8)^{\\circ}$ and, in the $\\overline{\\mathrm{MS}}$ scheme for $N_f=3$,\n$F^{0}(\\mu = 2\\,\\mathrm{GeV}) = 100.1(3.0)~\\text{MeV}$, where the decay\nconstants read $F^8_\\eta=F^8\\cos \\theta_8$, $F^8_{\\eta^\\prime}=F^8\\sin\n\\theta_8$, $F^0_\\eta=-F^0\\sin \\theta_0$ and $F^0_{\\eta^\\prime}=F^0\\cos\n\\theta_0$. For the gluonic matrix elements, we obtain $a_{\\eta}(\\mu =\n2\\,\\mathrm{GeV}) = 0.0170(10)\\,\\mathrm{GeV}^{3}$ and $a_{\\eta^{\\prime}}(\\mu =\n2\\,\\mathrm{GeV}) = 0.0381(84)\\,\\mathrm{GeV}^{3}$, where statistical and all\nsystematic errors are added in quadrature."
    },
    {
        "anchor": "Hadron Structure from Lattice QCD: Recent progress in lattice QCD calculations of nucleon structure will be\npresented. Calculations of nucleon matrix elements and form factors have long\nbeen difficult to reconcile with experiment, but with advances in both\nmethodology and computing resources, this situation is improving. Some\ncalculations have produced agreement with experiment for key observables such\nas the axial charge and electromagnetic form factors, and the improved\nunderstanding of systematic errors will help to increase confidence in\npredictions of unmeasured quantities. The long-omitted disconnected\ncontributions are now seeing considerable attention and some recent\ncalculations of them will be discussed.",
        "positive": "The Phase Diagram of Strong Coupling QCD including Gauge Corrections: The strong coupling limit of lattice QCD with staggered fermions has been\nstudied for decades, both via Monte Carlo and via mean field theory. In this\nmodel, the finite density sign problem can be made mild and the full phase\ndiagram can be obtained, even in the chiral limit. It is however desirable to\nunderstand the effect of a finite lattice gauge coupling $\\beta$ on the phase\ndiagram in the $\\mu-T$ plane in order to understand how it evolves into the\nphase diagram of continuum QCD. Here we discuss how to construct a partition\nfunction for non-zero lattice coupling, exact to $\\mathcal{O}(\\beta)$, and\npresent corresponding Monte Carlo results, in particular for corrections to the\nchiral susceptibility and to the phase diagram."
    },
    {
        "anchor": "Renormalisation of lattice currents and the calculation of decay\n  constants for dynamical staggered fermions: A numerical calculation of the lattice staggered renormalisation constants at\n$\\beta = 5.35$, $m = 0.01$ is presented. It is seen that there are considerable\nnon-perturbative effects present. As an application the vector decay constant\n$f_\\rho$ is estimated. (LAT92 contribution, one LATEX file with 3 postscript\nfigures appended.)",
        "positive": "Phase structure of the N=1 supersymmetric Yang-Mills theory at finite\n  temperature: Supersymmetry (SUSY) has been proposed to be a central concept for the\nphysics beyond the standard model and for a description of the strong\ninteractions in the context of the AdS/CFT correspondence. A deeper\nunderstanding of these developments requires the knowledge of the properties of\nsupersymmetric models at finite temperatures. We present a Monte Carlo\ninvestigation of the finite temperature phase diagram of the N=1 supersymmetric\nYang-Mills theory (SYM) regularised on a space-time lattice. The model is in\nmany aspects similar to QCD: quark confinement and fermion condensation occur\nin the low temperature regime of both theories. A comparison to QCD is\ntherefore possible. The simulations show that for N=1 SYM the deconfinement\ntemperature has a mild dependence on the fermion mass. The analysis of the\nchiral condensate susceptibility supports the possibility that chiral symmetry\nis restored near the deconfinement phase transition."
    },
    {
        "anchor": "Non-perturbative Renormalization of Bilinear Operators on Fine Lattice: We present results of the wave function renormalization factor $Z_q$ and mass\nrenormalization factor $Z_m$ obtained using non-perturbative renormalization\n(NPR) method in the RI-MOM scheme with HYP improved staggered quarks. We use\nfine ensembles of MILC asqtad lattices ($N_f = 2+1$) with $28^3 \\times 96$\ngeometry, $a \\approx 0.09$\\,fm, and $am_\\ell/am_s = 0.0062/0.031 $. We also\nstudy on scalability of $Z_q$ and $Z_m$ by comparing the results on the coarse\nand fine ensembles.",
        "positive": "Monte Carlo calculation for systems consisting of several coordinate\n  patches: I investigate the time step dependence of Monte Carlo simulations for\ncoordinate-spaces consisting of several patches. It is shown that a naive\nkinetic term does not necessarily converge to the same spectrum as a\nHamiltonian calculation. Then an improved kinetic term is presented which\nallows one to connect the Monte Carlo and Rayleigh-Ritz results of intermediate\nvolume SU(2) gauge theory."
    },
    {
        "anchor": "Continuum extrapolation of the critical endpoint in 4-flavor QCD with\n  Wilson-Clover fermions: We report our study on the critical endpoint of the finite temperature phase\ntransition in 4-flavor QCD with Wilson-Clover fermions. Using the kurtosis\nintersection method, we determined the critical endpoint on lattices with $N_t$\n= 4, 6 and 8. Our continuum extrapolated results show that the pseudo-scalar\nmeson mass at the critical endpoint, $m_\\mathrm{PS,E}$, for 4-flavor is clearly\nlarger than that for 3-flavor. We also compared our results to those with\nstaggered fermions and found that $m_\\mathrm{PS,E}/T_E$ for 4-flavor with\nWilson fermions might remain finite even in the continuum limit in contrast to\nthat with staggered fermions, where $m_\\mathrm{PS,E}/T_E$ is very close to\nzero, which suggests that the difference between Wilson and staggered fermions\nis at least not due to the rooting.",
        "positive": "Recent Progress in Lattice QCD Thermodynamics: This review gives a critical assessment of the current state of lattice\nsimulations of QCD thermodynamics and what it teaches us about hot hadronic\nmatter. It outlines briefly lattice methods for studying QCD at nonzero\ntemperature and zero baryon number density with particular emphasis on\nassessing and reducing cutoff effects. It discusses a variety of difficulties\nwith methods for determining the transition temperature. It uses results\nreported recently in the literature and at this conference for illustration,\nespecially those from a major study carried out by the HotQCD collaboration."
    },
    {
        "anchor": "Finite-size scaling tests for SU(3) lattice gauge theory with color\n  sextet fermions: The observed slow running of the gauge coupling in SU(3) lattice gauge theory\nwith two flavors of color sextet fermions naturally suggests it is a theory\nwith one relevant coupling, the fermion mass, and that at zero mass correlation\nfunctions decay algebraically. I perform a finite-size scaling study on\nsimulation data at two values of the bare gauge coupling with this assumption\nand observe a common exponent for the scaling of the correlation length with\nthe fermion mass, y_m ~ 1.5. An analysis of the scaling of valence Dirac\neigenvalues at one of these bare couplings produces a similar number.",
        "positive": "Multigrid Monte Carlo in the Sine Gordon model: We pose two questions about the dynamical critical behavior of multigrid\nMonte Carlo: Will a multigrid Monte Carlo simulation of the two dimensional\nSine Gordon model exhibit critical slowing down, as expected by a theoretical\nanalysis of Metropolis acceptance rates? Can we reduce critical slowing down\ncaused by decreasing acceptance rates on large blocks by performing more\nupdates on coarser lattices? To this end we simulate the model with a W-cycle\n(gamma = 2) and a higher cycle with gamma = 4 using piecewise constant\ninterpolation. The answer to the first question is positive, the answer to the\nsecond one is negative."
    },
    {
        "anchor": "Supersymmetry non-renormalization theorem from a computer and the\n  AdS/CFT correspondence: We perform Monte Carlo calculation of correlation functions in 4d N=4 super\nYang-Mills theory on R*S^3 in the planar limit. In order to circumvent the\nwell-known problem of lattice SUSY, we adopt the idea of a novel large-N\nreduction, which reduces the calculation to that of corresponding correlation\nfunctions in the plane-wave matrix model or the BMN matrix model. This model is\na 1d gauge theory with 16 supersymmetries, which can be simulated in a manner\nsimilar to the recent studies of the D0-brane system. We study two-point and\nthree-point functions of chiral primary operators at various coupling constant,\nand find that they agree with the free theory results up to overall constant\nfactors. The ratio of the overall factors for two-point and three-point\nfunctions agrees with the prediction of the AdS/CFT correspondence.",
        "positive": "Decay Constants of Pseudoscalar $D$-mesons in Lattice QCD with\n  Domain-Wall Fermion: We present the first study of the masses and decay constants of the\npseudoscalar $ D $ mesons in two flavors lattice QCD with domain-wall fermion.\nThe gauge ensembles are generated on the $24^3 \\times 48 $ lattice with the\nextent $ N_s = 16 $ in the fifth dimension, and the plaquette gauge action at $\n\\beta = 6.10 $, for three sea-quark masses with corresponding pion masses in\nthe range $260-475$ MeV. We compute the point-to-point quark propagators, and\nmeasure the time-correlation functions of the pseudoscalar and vector mesons.\nThe inverse lattice spacing is determined by the Wilson flow, while the strange\nand the charm quark masses by the masses of the vector mesons $ \\phi(1020) $\nand $ J/\\psi(3097) $ respectively. Using heavy meson chiral perturbation theory\n(HMChPT) to extrapolate to the physical pion mass, we obtain $ f_D =\n202.3(2.2)(2.6) $ MeV and $ f_{D_s} = 258.7(1.1)(2.9) $ MeV."
    },
    {
        "anchor": "Effective lattice Polyakov loop theory for finite temperature Yang-Mills: Effective Polyakov loop theories are a useful tool for an investigation of\npure Yang-Mills theory and full QCD. A systematic derivation of the effective\naction can be done in a spatial strong coupling expansion. Quite accurate\npredictions for the deconfinement phase transition of Yang-Mills theory have\nbeen obtained in this approach. Besides the critical couplings, further\nobservables can be measured in the effective theory. These provide additional\ntests for the reliability of the strong coupling approach and the truncation of\nthe effective action. In this contribution we will present recent results for\nthe free energy of the static quark-antiquark pair and the equation of state.",
        "positive": "Extraction of K-->pipi Matrix Elements with Wilson Fermions: We present the status of a lattice calculation for the K-->pipi matrix\nelements of the (delta S=1) effective weak Hamiltonian, directly with two pion\nin the final state. We study the energy shift of two pion in a finite volume\nboth in the I=0 and I=2 channels. We explain a method to avoid the Goldstone\npole contamination in the computation of renormalization constants for (delta\nI=3/2) operators. Finally we show some preliminary results for the matrix\nelements of (delta I=1/2) operators. Our quenched simulation is done at\nbeta=6.0, with Wilson fermions, on a (24^3 X 64) lattice."
    },
    {
        "anchor": "Controlling Excited-State Contributions with Distillation in Lattice QCD\n  Calculations of Nucleon Isovector Charges $g_S^{u-d}$, $g_A^{u-d}$,\n  $g_T^{u-d}$: We investigate the application of the distillation smearing approach, and the\nuse of the variational method with an extended basis of operators facilitated\nby this approach, on the calculation of the nucleon isovector charges\n$g_S^{u-d}$, $g_A^{u-d}$, and $g_T^{u-d}$. We find that the better sampling of\nthe lattice enabled through the use of distillation yields a substantial\nreduction in the statistical uncertainty in comparison with the use of\nalternative smearing methods, and furthermore, appears to offer better control\nover the contribution of excited-states compared to use of a single, local\ninterpolating operator. The additional benefit arising through the use of the\nvariational method in the distillation approach is less dramatic, but\nnevertheless significant given that it requires no additional Dirac inversions.",
        "positive": "Interglueball potential in SU(N) lattice gauge theory: We report on our calculation of the interglueball potentials in SU(2), SU(3),\nand SU(4) lattice Yang-Mills theories using the indirect (so-called HAL QCD)\nmethod. We use the cluster decomposition error reduction technique to improve\nthe statistical accuracy of the glueball correlators. After calculating the\nglueball scattering cross section in SU(2) Yang-Mills theory and combining with\nthe observational data of the dark matter mass distributions, we derive the\nlower limit on the scale parameter."
    },
    {
        "anchor": "QCD thermodynamics at non-zero isospin asymmetry: We study the thermodynamic properties of QCD at nonzero isospin chemical\npotential using improved staggered quarks at physical quark masses. In\nparticular, we discuss the determination of the equation of state at zero and\nnonzero temperatures and show results. Using the results for the isospin\ndensity $n_I$, we also determine the phase diagram in the $(n_I,T)$-plane.",
        "positive": "Monopoles and Spatial String Tension in the High Temperature Phase of\n  SU(2) QCD: We studied a behavior of monopole currents in the high temperature\n(deconfinement) phase of abelian projected finite temperature SU(2) QCD in\nmaximally abelian gauge. Wrapped monopole currents closed by periodic boundary\nplay an important role for the spatial string tension which is a\nnon-perturbative quantity in the deconfinement phase. The wrapped monopole\ncurrent density seems to be non-vanishing in the continuum limit. These results\nmay be related to Polyakov's analysis of the confinement mechanism using\nmonopole gas in 3-dimensional SU(2) gauge theory with Higgs fields."
    },
    {
        "anchor": "An Improved Acceptance Procedure for the Hybrid Monte Carlo Algorithm: The probability of accepting a candidate move in the hybrid Monte Carlo\nalgorithm can be increased by considering a transition to be between windows of\nseveral states at the beginning and end of the trajectory, with a state within\nthe selected window being chosen according to the Boltzmann probabilities. The\ndetailed balance condition used to justify the algorithm still holds with this\nprocedure, provided the start state is randomly positioned within its window.\nThe new procedure is shown empirically to significantly improve performance for\na test system of uncoupled oscillators.",
        "positive": "A Relativistic $O(a^2)$ Improved Action for Heavy Quarks: We extend the Fermilab formalism for heavy quarks to develop an $O(a^2)$\nimproved relativistic action. We discuss our construction of the action,\nincluding the identification of redundant operators and the calculation of the\nimprovement coefficients."
    },
    {
        "anchor": "BRST symmetry vs. Horizon condition in Yang-Mills theories: We show that in SU(2) Yang-Mills theories a simple relation exists between\nlattice gluon propagators in Coulomb and Landau gauge and discuss the physical\nimplications of such result. In particular, the realization of the\nGribov-Zwanziger confinement mechanism in Coulomb gauge, linked to\ndual-superconductivity, would imply that the standard BRST charge must be ill\ndefined non perturbatively. As a consequence, the Kugo-Ojima confinement\ncriterion, which relies on BRST charge conservation beyond perturbation theory,\nwould not be fulfilled.",
        "positive": "Large mass hierarchies from strongly-coupled dynamics: Motivated by the absence of signals of new physics at the LHC, which seems to\nimply the presence of large mass hierarchies, we investigate the theoretical\npossibility that these could arise dynamically in new strongly-coupled gauge\ntheories extending the standard model of particle physics. To this purpose, we\nstudy lattice data on non-Abelian gauge theories in the (near-)conformal\nregime---specifically, $\\mathrm{SU}(2)$ with $N_{\\mathrm{f}}=1$ and $2$\ndynamical fermion flavours in the adjoint representation. We focus our\nattention on the ratio $R$ between the masses of the lightest spin-2 and spin-0\nresonances, and draw comparisons with a simple toy model in the context of\ngauge/gravity dualities. For models in which large anomalous dimensions arise\ndynamically, we show indications that this mass ratio can be large, with $R >\n5$. Moreover, our results suggest that $R$ might be related to universal\nproperties of the IR fixed point. Our findings provide an interesting step\ntowards understanding large mass ratios in the non-perturbative regime of\nquantum field theories with (near) IR conformal behaviour."
    },
    {
        "anchor": "Classical Limits of Scalar and Tensor Gauge Operators Based on the\n  Overlap Dirac Matrix: It was recently proposed by the second author to consider lattice\nformulations of QCD in which complete actions, including the gauge part, are\nbuilt explicitly from a given Dirac operator D. In a simple example of such\ntheory, the gauge action is proportional to the trace of Ginsparg-Wilson\noperator D chosen to define the quark dynamics. This construction relies on the\nproposition that the classical limit of lattice gauge operator tr D(x,x) is\nproportional to tr F.F(x) (up to an additive constant). Here we show this for\nthe case of the overlap Dirac operator using both analytical and numerical\nmethods. We carry out the same analysis also for the tensor component of D,\nwhich is similarly related to the field-strength tensor F, and obtain results\nidentical to our previous derivation that used different approach. The\ncorresponding proportionality constants are computed to high precision for wide\nrange of the negative mass parameter values, and it is verified that they are\nthe same in finite and infinite volumes.",
        "positive": "Finite Size Analysis of the One-dimensional $q = \\infty$ Clock Model: We analyze the finite size scaling of the $q$-state clock model in the $q\n\\rightarrow \\infty$ limit. The behaviors of the specific heat, Binder-Landau\nand U4 cumulants agree with the Borgs-Koteck\\'y ans\\\"atz for first order phase\ntransitions. However, we find that the leading correction to the position of\nthe extremal points of these quantities is not universal. On the other hand,\nthe finite size corrections to the mass gap behave like for second order phase\ntransitions. In particular, the curves corresponding to different size\napproximations do not cross in the vicinity of the transition points. The\nfeature is associated to the existence of a divergent correlation length and\nholds for a wider class of models."
    },
    {
        "anchor": "Comparison of the gradient flow with cooling in $SU(3)$ pure gauge\n  theory: The gradient (Wilson) flow has been introduced recently in order to provide a\nsolid theoretical framework for the smoothing of ultraviolet noise in lattice\ngauge configurations. It is interesting to ask how it compares with other, more\nheuristic and numerically cheaper smoothing techniques, such as standard\ncooling. In this study we perform such a comparison, focusing on observables\nrelated to topology. We show that, already for moderately small lattice\nspacings, standard cooling and the gradient flow lead to equivalent results,\nboth for average quantities and configuration by configuration.",
        "positive": "Hadron Masses from the Valence Approximation to Lattice QCD: We evaluate pseudoscalar, vector, spin 1/2 and spin 3/2 baryon masses\npredicted by lattice QCD with Wilson quarks in the valence (quenched)\napproximation for a range of different values of lattice spacing, lattice\nvolume and quark mass. Extrapolating these results to physical quark mass, then\nto zero lattice spacing and infinite volume we obtain values for eight mass\nratios. We also determine the zero lattice spacing, infinite volume limit of an\nalternate set of five quantities found without extrapolation in quark mass.\nBoth sets of predictions differ from the corresponding observed values by\namounts consistent with the predicted quantities' statistical uncertainties."
    },
    {
        "anchor": "QCD on GPUs: cost effective supercomputing: The exponential growth of floating point power in graphics processing units\n(GPUs), together with their low cost, has given rise to an attractive platform\nupon which to deploy lattice QCD calculations. GPUs are essentially many\n(O(100)) core chips, that are programmed using a massively threaded\nenvironment, and so are representative of the future of high performance\ncomputing (HPC). The large ratio of raw floating point operations per second to\nmemory bandwidth that is characteristic of GPUs necessitates that unique\nalgorithmic design choices are made to harness their full potential. We review\nthe progress to date in using GPUs for large scale calculations, and contrast\nGPUs against more traditional HPC architectures",
        "positive": "On the behaviour of spatial Wilson loops in the high temperature phase\n  of Lattice Gauge Theories: The behaviour of the space-like string tension in the high temperature phase\nis studied. Data obtained in the $Z_2$ gauge model in (2+1) dimensions are\ncompared with predictions of a simple model of a fluctuating flux tube with\nfinite thickness. It is shown that in the high temperature phase contributions\ncoming from the fluctuations of the flux tube vanish. As a consequence we also\nshow that in (2+1) dimensional gauge theories the thickness of the flux tube\ncoincides with the inverse of the deconfinement temperature."
    },
    {
        "anchor": "Lattice QCD with Eight Degenerate Quark Flavors: We report on simulations of QCD with many flavors of degenerate quarks, the\nDBW2 gauge action and naive staggered fermions, using the rational hybrid Monte\nCarlo algorithm. We primarily focus on eight degenerate quark flavors where a\nvariety of values of the coupling constant and quark mass have been used in the\nsimulations. The scaling behavior of the hadron spectrum and the string tension\nof the heavy quark potential is studied, to probe whether the zero temperature,\ncontinuum limit of the theory breaks chiral symmetry.",
        "positive": "D and D_s meson spectroscopy from lattice QCD: We present results for the low-lying spectrum of D and D_s mesons from a\nlattice QCD calculation on 2+1 flavor Clover-Wilson configurations generated by\nthe PACS-CS collaboration. In particular S- and P-wave states of charmed and\ncharmed-strange mesons are explored for pion masses down to 156MeV. For the\nheavy quark, the Fermilab method is employed. In addition to ground states,\nsome excited states are extracted using the variational method. To check our\nsetup, calculations of the charmonium spectrum are also carried out. For\ncharmonium, the low-lying spectrum agrees favorably with experiment. For\nheavy-strange and heavy-light systems substantial differences in comparison to\nexperiment values remain in channels with nearby scattering states."
    },
    {
        "anchor": "The Emergence of a Heavy Quark Family on a Lattice: Within the framework of the ``Rome approach'' for a lattice chiral gauge\ntheory, the four-quark interaction with flavour symmetry is included. We\nanalyse spontaneous symmetry breaking and compute composite modes and their\ncontributions to the ground state energy. As a result, it is shown that the\nemergence of a heavy quark family is the energetically favoured solution.",
        "positive": "Nucleon isovector form factors from physical-mass 2+1-flavor dynamical\n  domain-wall QCD: The current status is reported of joint lattice numerical calculations by LHP\nand RBC collaborations of isovector nucleon form factors using 2+1-flavor\nphysical-mass domain-wall fermions ensemble at a lattice cutoff $a^{-1}$ of\n1.730(4) GeV and spatial volume of $(La=\\mbox{\\rm 5.471(13)fm})^3$ generated\njointly by RBC and UKQCD collaborations."
    },
    {
        "anchor": "Clover fermions in the adjoint representation and simulations of\n  supersymmetric Yang-Mills theory: Clover improvement is the standard choice for lattice simulations of QCD,\nwhen the lattice artefacts coming from Wilson fermions have to be reduced.\nHowever, the clover improvement is not limited to QCD, but can be applied to a\nwider range of theories with fermions in higher representations of the gauge\ngroup SU(N), like the adjoint fermions required by supersymmetry or by\ntechnicolor theories. We present the calculation of the clover coefficient up\nto one loop order with standard perturbation theory for these models.\nApplications of clover fermions to supersymmetric Yang-Mills theory are also\ndiscussed.",
        "positive": "Scalar Glueball in Radiative $J/\u03c8$ Decay on Lattice: The form factors in the radiative decay of $J/\\psi$ to a scalar glueball are\nstudied within quenched lattice QCD on anisotropic lattices. The continuum\nextrapolation is carried out by using two different lattice spacings. With the\nresults of these form factors, the partial width of $J/\\psi$ radiatively\ndecaying into the pure gauge scalar glueball is predicted to be 0.35(8) keV,\nwhich corresponds to a branching ratio of 3.8(9)x10^{-3}. By comparing with the\nexperiments, out results indicate that f_0(1710) has a larger overlap with the\npure gauge glueball than other related scalar mesons."
    },
    {
        "anchor": "Axial anomaly and Ginsparg-Wilson fermions in the Lattice Dirac Sea\n  picture: The axial anomaly equation in 1+1 dimensional QED is obtained on the lattice\nfor fermions obeying the Ginsparg-Wilson relation. We make use of the\nproperties of the Lattice Dirac sea to investigate the connection between the\nanomaly and the Ginsparg-Wilson operator in the Hamiltonian picture. The\ncorrect anomaly is reproduced for gauge fields whose characteristic time is\nmuch larger than the lattice spacing, which is the regime where the adiabatic\napproximation applies. A non-zero Wilson $r$ parameter is necessary to get the\ncorrect anomaly. The anomaly is shown to be independent of $r$ for $r>0.5$. The\ngeneralization to 3+1 dimensions is also discussed.",
        "positive": "Deconfinement critical point of lattice QCD with $N_{\\rm f}=2$ Wilson\n  fermions: The ${\\rm SU}(3)$ pure gauge theory exhibits a first-order thermal\ndeconfinement transition due to spontaneous breaking of its global $Z_3$ center\nsymmetry. When heavy dynamical quarks are added, this symmetry is broken\nexplicitly and the transition weakens with decreasing quark mass until it\ndisappears at a critical point. We compute the critical hopping parameter and\nthe associated pion mass for lattice QCD with $N_f=2$ degenerate standard\nWilson fermions on $N_\\tau\\in\\{6,8,10\\}$ lattices, corresponding to lattice\nspacings $a=0.12\\, {\\rm fm}$, $a=0.09\\, {\\rm fm}$, $a=0.07\\, {\\rm fm}$,\nrespectively. Significant cut-off effects are observed, with the first-order\nregion growing as the lattice gets finer. While current lattices are still too\ncoarse for a continuum extrapolation, we estimate $m_\\pi^c\\approx 4 {\\rm GeV}$\nwith a remaining systematic error of $\\sim 20\\%$. Our results allow to assess\nthe accuracy of the LO and NLO hopping expanded fermion determinant used in the\nliterature for various purposes. We also provide a detailed investigation of\nthe statistics required for this type of calculation, which is useful for\nsimilar investigations of the chiral transition."
    },
    {
        "anchor": "Euclidean correlators at imaginary spatial momentum and their relation\n  to the thermal photon emission rate: The photon emission rate of a thermally equilibrated system is determined by\nthe imaginary part of the in-medium retarded correlator of the electromagnetic\ncurrent transverse to the spatial momentum of the photon. In a\nLorentz-covariant theory, this correlator can be parametrized by a scalar\nfunction ${\\cal G}_R(u\\cdot {\\cal K},{\\cal K}^2)$, where $u$ is the fluid\nfour-velocity and ${\\cal K}$ corresponds to the momentum of the photon. We\npropose to compute the analytic continuation of ${\\cal G}_R(u\\cdot {\\cal\nK},{\\cal K}^2)$ at fixed, vanishing virtuality ${\\cal K}^2$, to imaginary\nvalues of the first argument, $u\\cdot {\\cal K}= i\\omega_n$. At these\nkinematics, the retarded correlator is equal to the Euclidean correlator\n$G_E(\\omega_n, k=i\\omega_n)$, whose first argument is the Matsubara frequency\nand the second is the spatial momentum. The Euclidean correlator, which is\ndirectly accessible in lattice QCD simulations, must be given an imaginary\nspatial momentum in order to realize the photon on-shell condition. Via a\nonce-subtracted dispersion relation that we derive in a standard way at fixed\n${\\cal K}^2=0$, the Euclidean correlator with imaginary spatial momentum is\nrelated to the photon emission rate. The relation allows for a more direct\nprobing of the real-photon emission rate of the quark-gluon plasma in lattice\nQCD than the dispersion relations which have been used so far, the latter being\nat fixed spatial photon momentum $k$ and thus involving all possible\nvirtualities of the photon.",
        "positive": "Unitary Evolution on a Discrete Phase Space: We construct unitary evolution operators on a phase space with power of two\ndiscretization. These operators realize the metaplectic representation of the\nmodular group SL(2,Z_{2^n}). It acts in a natural way on the coordinates of the\nnon-commutative 2-torus, T_{2^n}^2$ and thus is relevant for non-commutative\nfield theories as well as theories of quantum space-time. The class of\noperators may also be useful for the efficient realization of new quantum\nalgorithms."
    },
    {
        "anchor": "Finite Volume Effects on the Extraction of Form Factors at Zero Momentum: Hadronic matrix elements that depend on momentum are required for numerous\nphenomenological applications. Probing the low-momentum regime is often\nproblematic for lattice QCD computations on account of the restriction to\nperiodic momentum modes. Recently a novel method has been proposed to compute\nmatrix elements at zero momentum, for which straightforward evaluation of the\nmatrix elements would otherwise yield a vanishing result. We clarify an\nassumption underlying this method, and thereby establish the theoretical\nframework required to address the associated finite volume effects. Using the\npion electromagnetic form factor as an example, we show how the charge radius\nand two higher moments can be calculated at zero momentum transfer, and\ndetermine the corresponding finite volume effects. These computations are\nperformed using chiral perturbation theory to account for modified infrared\nphysics, and can be generalized to ascertain finite volume effects for other\nhadronic matrix elements extracted at zero momentum.",
        "positive": "The chromomagnetic operator on the lattice: We study matrix elements of the \"chromomagnetic\" operator on the lattice.\nThis operator is contained in the strangeness-changing effective Hamiltonian\nwhich describes electroweak effects in the Standard Model and beyond.\n  Having dimension 5, the chromomagnetic operator is characterized by a rich\npattern of mixing with other operators of equal and lower dimensionality,\nincluding also non gauge invariant quantities; it is thus quite a challenge to\nextract from lattice simulations a clear signal for the hadronic matrix\nelements of this operator.\n  We compute all relevant mixing coefficients to one loop in lattice\nperturbation theory; this necessitates calculating both 2-point\n(quark-antiquark) and 3-point (gluon-quark-antiquark) Green's functions at\nnonzero quark masses. We use the twisted mass lattice formulation, with\nSymanzik improved gluon action.\n  For a comprehensive presentation of our results, along with detailed\nexplanations and a more complete list of references, we refer to our\nforthcoming publication [1]."
    },
    {
        "anchor": "Analyticity in theta on the lattice and the large volume limit of the\n  topological susceptibility: Non-analyticity of QCD with a \\theta term at \\theta=0 may signal a\nspontaneous breaking of both parity and time reversal invariance. We address\nthis issue by investigating the large volume limit of the topological\nsusceptibility $\\chi$ in pure SU(3) gauge theory. We obtain an upper bound for\nthe symmetry breaking order parameter <Q> and, as a byproduct, the value\n\\chi=(173.4(+/- 0.5)(+/- 1.2)(+1.1 / -0.2) MeV)^4 at \\beta=6 (a approx= 0.1\nfermi). The errors are the statistical error from our data, the one derived\nfrom the value used for \\Lambda_L and an estimate of the systematic error\nrespectively.",
        "positive": "`t Hooft model on the Lattice: Lattice results are presented for the meson spectrum of 1+1 dimensional gauge\ntheory at large $N$, using the Twisted Eguchi-Kawai model. Comparison is made\nto the results obtained by `t Hooft in the light cone gauge."
    },
    {
        "anchor": "Higgs mass bounds from a chirally invariant lattice Higgs-Yukawa model\n  with overlap fermions: We study the parameter dependence of the Higgs mass in a chirally invariant\nlattice Higgs-Yukawa model emulating the same Higgs-fermion coupling structure\nas in the Higgs sector of the electroweak Standard Model. Eventually, the aim\nis to establish upper and lower Higgs mass bounds. Here we present our\npreliminary results on the lower Higgs mass bound at several selected values\nfor the cutoff and give a brief outlook towards the upper Higgs mass bound.",
        "positive": "The strong-coupling limit of minimal lattice Landau gauge: We study the gluon and ghost propagators of lattice Landau gauge in the\nstrong coupling limit $\\beta = 0$ in pure SU(2) lattice gauge theory to find\nevidence of the conformal infrared behaviour of these propagators as predicted\nby a variety of functional continuum methods for asymptotically small momenta\n$q^2 \\ll \\Lambda_\\mathrm{QCD}^2$. In the strong-coupling limit, this same\nbehaviour is obtained for the larger values of $a^2q^2$ (in units of the\nlattice spacing $a$), where it is otherwise swamped by the gauge field\ndynamics. Deviations for $a^2 q^2 < 1 $ are well parametrized by a transverse\ngluon mass $\\propto 1/a$. Perhaps unexpectedly, these deviations are thus no\nfinite-volume effect but persist in the infinite-volume limit. They furthermore\ndepend on the definition of gauge fields on the lattice, while the asymptotic\nconformal behaviour does not."
    },
    {
        "anchor": "FermiQCD: A tool kit for parallel lattice QCD applications: We present here the most recent version of FermiQCD, a collection of C++\nclasses, functions and parallel algorithms for lattice QCD, based on Matrix\nDistributed Processing. FermiQCD allows fast development of parallel lattice\napplications and includes some SSE2 optimizations for clusters of Pentium 4\nPCs.",
        "positive": "Mixed action computations on fine dynamical lattices: We report on our first experiences in simulating Neuberger valence fermions\non CLS $N_f=2$ configurations with light sea quark masses and small lattice\nspacings. Valence quark masses are considered that allow to explore the\nmatching to (partially quenched) chiral perturbation theory both in the\n$\\epsilon$- and $p$-regimes. The setup is discussed, and first results are\npresented for spectral observables."
    },
    {
        "anchor": "Symmetric Mass Generation in Lattice Gauge Theory: We construct a four dimensional lattice gauge theory in which fermions\nacquire mass without breaking symmetries as a result of gauge interactions. Our\nmodel consists of reduced staggered fermions transforming in the bifundamental\nrepresentation of a $SU(2)\\times SU(2)$ gauge symmetry. This fermion\nrepresentation ensures that single site bilinear mass terms vanish identically.\nA symmetric four fermion operator is however allowed and we show numerical\nresults that show that a condensate of this operator develops in the vacuum.",
        "positive": "B Mixing in the Standard Model and Beyond: Lattice QCD: We give a brief overview and progress report on our lattice QCD calculation\nof neutral B mixing hadronic matrix elements needed for Standard Model and\nBeyond the Standard Model physics. Reference [1] contains more details and\nresults."
    },
    {
        "anchor": "Cost of the Generalised Hybrid Monte Carlo Algorithm for Free Field\n  Theory: We study analytically the computational cost of the Generalised Hybrid Monte\nCarlo (GHMC) algorithm for free field theory. We calculate the Metropolis\nacceptance probability for leapfrog and higher-order discretisations of the\nMolecular Dynamics (MD) equations of motion. We show how to calculate\nautocorrelation functions of arbitrary polynomial operators, and use these to\noptimise the GHMC momentum mixing angle, the trajectory length, and the\nintegration stepsize for the special cases of linear and quadratic operators.\nWe show that long trajectories are optimal for GHMC, and that standard HMC is\nmore efficient than algorithms based on Second Order Langevin Monte Carlo\n(L2MC), sometimes known as Kramers Equation. We show that contrary to naive\nexpectations HMC and L2MC have the same volume dependence, but their dynamical\ncritical exponents are z = 1 and z = 3/2 respectively.",
        "positive": "Numerical Stability of Lanczos Methods: The Lanczos algorithm for matrix tridiagonalisation suffers from strong\nnumerical instability in finite precision arithmetic when applied to evaluate\nmatrix eigenvalues. The mechanism by which this instability arises is well\ndocumented in the literature. A recent application of the Lanczos algorithm\nproposed by Bai, Fahey and Golub allows quadrature evaluation of inner products\nof the form $\\psi^\\dagger g(A) \\psi$. We show that this quadrature evaluation\nis numerically stable and explain how the numerical errors which are such a\nfundamental element of the finite precision Lanczos tridiagonalisation\nprocedure are automatically and exactly compensated in the Bai, Fahey and Golub\nalgorithm. In the process, we shed new light on the mechanism by which roundoff\nerror corrupts the Lanczos procedure"
    },
    {
        "anchor": "First study of $N_f=2+1+1$ lattice QCD with physical domain-wall quarks: Using 10-16 units of Nvidia DGX-1, we have generated the first gauge ensemble\nfor $N_f=2+1+1$ lattice QCD with physical $(u/d, s, c)$ domain-wall quarks, on\nthe $ 64^4 $ lattice with lattice spacing $a \\sim 0.064 $ fm ($ L > 4 $ fm, and\n$ M_\\pi L > 3 $). The salient feature of this gauge ensemble is that the chiral\nsymmetry is preserved to a high precision and all topological sectors are\nsampled ergodically. In this paper, we present the first results of the\ntopological susceptibility and the ground-state hadron mass spectra.",
        "positive": "Point-to-point Hadron Correlation Functions using the\n  Sheikholeslami--Wohlert Action: We calculate correlations between hadronic current operators as a function of\ntheir spatial separation, in a quenched lattice QCD simulation at $\\beta=6.2$\non a $24^3\\times48$ lattice. The lattice fermion formulation used is that due\nto Sheikholeslami and Wohlert. The correlation functions are then compared with\nthe corresponding quantities calculated in the infinite volume chiral limit of\nthe non-interacting theory. The ratio of the two quantities contains\ninformation on the vacuum structure of QCD. Results obtained are consistent\nwith previous studies, and with known hadron phenomenology, although certain\nfeatures of the fermion action used make it impossible to probe the $r\\to0$\nlimit directly, thus limiting the accuracy possible."
    },
    {
        "anchor": "Comment on \"Lattice Gluon and Ghost Propagators, and the Strong Coupling\n  in Pure $SU(3)$ Yang-Mills Theory: Finite Lattice Spacing and Volume Effects\": The authors of ref. Phys.Rev. D94 (2016) no.1, 014502 reported about a\ncareful analysis of the impact of lattice artifacts on the $SU(3)$ gauge-field\npropagators. In particular, they found that the low-momentum behavior of the\nrenormalized propagators depends on the lattice bare coupling and interpreted\nthis fact as the result of it being affected by finite lattice spacing\nartifacts. We do not share this interpretation and present here a different and\nmore suitable explanation for these results.",
        "positive": "Study of QCD critical point using canonical ensemble method: The existence of the QCD critical point at non-zero baryon density is not\nonly of great interest for experimental physics but also a challenge for the\ntheory. We use lattice simulations based on the canonical ensemble method to\nexplore the finite baryon density region and look for the critical point. We\nscan the phase diagram of QCD with three degenerate quark flavors using clover\nfermions with $m_\\pi \\approx 700{MeV}$ on $6^3\\times4$ lattices. We measure the\nbaryon chemical potential as we increase the density and we see the\ncharacteristic \"S-shape\" that signals the first order phase transition. We\ndetermine the phase boundary by Maxwell construction and report our preliminary\nresults for the location of critical point."
    },
    {
        "anchor": "Non-perturbative renormalization constants on the lattice from flavour\n  non-singlet Ward identities: By imposing axial and vector Ward identities for flavour-non-singlet\ncurrents, we estimate in the quenched approximation the non-perturbative values\nof combinations of improvement coefficients, which appear in the expansion\naround the massless case of the renormalization constants of axial,\npseudoscalar, vector, scalar non-singlet currents and of the renormalized mass.\n  These coefficients are relevant for the completion of the improvement\nprogramme to O(a) of such operators.\n  The simulations are performed with a clover Wilson action non-perturbatively\nimproved.",
        "positive": "Parton distribution functions beyond leading twist from lattice QCD: The\n  $h_L(x)$ case: We report the first-ever calculation of the isovector flavor combination of\nthe chiral-odd twist-3 parton distribution $h_L(x)$ for the proton from lattice\nQCD. We employ gauge configurations with two degenerate light, a strange and a\ncharm quark ($N_f=2+1+1$) of maximally twisted mass fermions with a clover\nimprovement. The lattice has a spatial extent of 3 fm and lattice spacing of\n0.093 fm. The values of the quark masses lead to a pion mass of $260$ MeV. We\nuse a source-sink time separation of 1.12 fm to control contamination from\nexcited states. Our calculation is based on the quasi-distribution approach,\nwith three values for the proton momentum: 0.83 GeV, 1.25 GeV, and 1.67 GeV.\nThe lattice data are renormalized non-perturbatively using the RI$'$ scheme,\nand the final result for $h_L(x)$ is presented in the $\\overline{\\rm MS}$\nscheme at the scale of 2 GeV. Furthermore, we compute in the same setup the\ntransversity distribution, $h_1(x)$, which allows us, in particular, to compare\n$h_L(x)$ to its Wandzura-Wilczek approximation. We also combine results for the\nisovector and isoscalar flavor combinations to disentangle the individual quark\ncontributions for $h_1(x)$ and $h_L(x)$, and address the Wandzura-Wilczek\napproximation in that case as well."
    },
    {
        "anchor": "Applied lattice gauge calculations: diquark content of the nucleon: As an example of an application of lattice QCD we describe a computation of\nfour-quark operators in the nucleon. The results are interpreted in a diquark\nlanguage.",
        "positive": "Exploiting the hopping parameter expansion in the hybrid Monte Carlo\n  (HMC) simulation of lattice QCD with two degenerate flavours of Wilson\n  fermions: We show how the hopping parameter expansion at order $\\kappa^2$ and\n$\\kappa^4$ can be exploited in the simulation of lattice QCD with two flavours\nof degenerate Wilson fermions. A natural extension of this idea is a\n\"UV-filtering\" by using rooted polynomials. These approaches can be easily\ncombined with, for example, mass preconditioning. First numerical tests are\nperformed for the Wilson gauge action at $\\beta=5.6$ and $\\kappa=0.156$ and\n$0.1575$."
    },
    {
        "anchor": "Multilevel Monte Carlo for quantum mechanics on a lattice: Monte Carlo simulations of quantum field theories on a lattice become\nincreasingly expensive as the continuum limit is approached since the cost per\nindependent sample grows with a high power of the inverse lattice spacing.\nSimulations on fine lattices suffer from critical slowdown, the rapid growth of\nautocorrelations in the Markov chain. This causes a strong increase in the\nnumber of lattice configurations that have to be generated to obtain\nstatistically significant results. This paper discusses hierarchical sampling\nmethods to tame the growth in autocorrelations. Combined with multilevel\nvariance reduction, this significantly reduces the computational cost of\nsimulations for given tolerances $\\epsilon_{\\text{disc}}$ on the discretisation\nerror and $\\epsilon_{\\text{stat}}$ on the statistical error. For observables\nwith lattice errors of order $\\alpha$ and integrated autocorrelation times that\ngrow like $\\tau_{\\mathrm{int}}\\propto a^{-z}$, multilevel Monte Carlo (MLMC)\nreduces the cost from\n$\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}\\epsilon_{\\text{disc}}^{-(1+z)/\\alpha})$\nto $\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}\\vert\\log \\epsilon_{\\text{disc}}\n\\vert^2+\\epsilon_{\\text{disc}}^{-1/\\alpha})$ or\n$\\mathcal{O}(\\epsilon_{\\text{stat}}^{-2}+\\epsilon_{\\text{disc}}^{-1/\\alpha})$.\nHigher gains are expected for simulations of quantum field theories in $D$\ndimensions. The efficiency of the approach is demonstrated on two model\nsystems, including a topological oscillator that is badly affected by critical\nslowdown from topological charge freezing. On fine lattices, the new methods\nare orders of magnitude faster than standard Hybrid Monte Carlo sampling. For\nhigh resolutions, MLMC can be used to accelerate even the cluster algorithm for\nthe topological oscillator. Performance is further improved through\nperturbative matching which guarantees efficient coupling of theories on the\nmultilevel hierarchy.",
        "positive": "Self-avoiding random surfaces with fluctuating topology: A gas of self-avoiding surfaces with an arbitrary polynomial coupling to the\ngaussian curvature and an extrinsic curvature term can be realized in a\nthree-dimensional Ising bcc lattice with only three local couplings. Similar\nthree parameter realizations are valid also in other lattices. The relation\nbetween the crumpling transition and the roughening is discussed. It turns out\nthat the mean area of these surfaces is proportional to its genus."
    },
    {
        "anchor": "Exact local fermionic zero modes: We introduce a simple method to find localized exact fermionic zero modes for\nany local fermionic action. The zero modes are attached to specific local gauge\nconfigurations. Examples are provided for staggered and Wilson fermion actions\nin 2-6 dimensions, at finite and infinite lattice volumes, and for abelian and\nnon-abelian gauge groups. One of our concrete results is that a finite density\nof almost zero modes must occur in quenched four dimensional lattice gauge\ntheory simulations that use traditional methods. This density is exponentially\nsuppressed in the gauge coupling constant.",
        "positive": "Mass Preconditioning for the Exact One-Flavor Action in Lattice QCD with\n  Domain-Wall Fermion: The mass-preconditioning (MP) technique has become a standard tool to enhance\nthe efficiency of the hybrid Monte-Carlo simulation (HMC) of lattice QCD with\ndynamical quarks, for 2-flavors QCD with degenerate quark masses, as well as\nits extension to the case of one-flavor by taking the square-root of the\nfermion determinant of 2-flavors with degenerate masses. However, for lattice\nQCD with domain-wall fermion, the fermion determinant of any single fermion\nflavor can be expressed as a functional integral with an exact pseudofermion\naction $ \\phi^\\dagger H^{-1} \\phi $, where $ H^{-1} $ is a positive-definite\nHermitian operator without taking square-root, and with the chiral structure\n\\cite{Chen:2014hyy}. Consequently, the mass-preconditioning for the exact\none-flavor action (EOFA) does not necessarily follow the conventional (old) MP\npattern. In this paper, we present a new mass-preconditioning for the EOFA,\nwhich is more efficient than the old MP which we have used in Refs.\n\\cite{Chen:2014hyy,Chen:2014bbc}. We perform numerical tests in lattice QCD\nwith $ N_f = 1 $ and $ N_f = 1+1+1+1 $ optimal domain-wall quarks, with one\nmass-preconditioner applied to one of the exact one-flavor actions, and we find\nthat the efficiency of the new MP is more than 20\\% higher than that of the old\nMP."
    },
    {
        "anchor": "First quenched results for the matrix elements of the B_{B_s} mixing\n  parameter in the static limit from tmQCD: We report on a non-perturbative study of the scale-dependent renormalization\nfactors of a multiplicatively renormalizable basis of Delta B=2 parity-odd\nfour-fermion operators in quenched lattice QCD. We also present some\npreliminary results of the matrix elements related to the mixing parameter of\nthe B_s-meson. In our lattice formulation, the heavy quark is treated in the\nstatic approximation, while the strange one belongs to a doublet of twisted\nmass fermions at full twist, i.e. with twist angle alpha=pi/2. In this\nframework, the parity-even Delta B=2 four-fermion operators responsible for the\nmixing are rotated onto a linear combination of parity-odd operators in the\nabove-mentioned basis. Their physical matrix elements between static B_s-mesons\nare extracted from lattice correlators with Schroedinger functional boundary\nconditions. We observe a suppression of excited state contributions to the\nB_{B_s} mixing parameter and speculate about possible explanations.",
        "positive": "Charged Hadron Properties in Background Electric Fields: We report on a lattice calculation demonstrating a novel new method to\nextract the electric polarizability of charged pseudo-scalar mesons by\nanalyzing two point correlation functions computed in classical background\nelectric fields."
    },
    {
        "anchor": "Species Doublers as Super Multiplet Partners in Lattice Supersymmetry: We propose a new lattice superfield formalism in momentum representation\nwhich accommodates species doublers of the lattice fermions and their bosonic\ncounterparts as super multiplets. We explicitly show that one dimensional $N=2$\nmodel with interactions has exact supersymmetry on the lattice for all super\ncharges with lattice momentum. In coordinate representation the finite\ndifference operator is made to satisfy Leibnitz rule by introducing a non local\nproduct, the \"star\" product, and the exact lattice supersymmetry is realized.\nSupersymmetric Ward identities are shown to be satisfied at one loop level.",
        "positive": "Curvature and scaling in 4D dynamical triangulation: We study the average number of simplices $N'(r)$ at geodesic distance $r$ in\nthe dynamical triangulation model of euclidean quantum gravity in four\ndimensions. We use $N'(r)$ to explore definitions of curvature and of effective\nglobal dimension. An effective curvature $R_V$ goes from negative values for\nlow $\\kappa_2$ (the inverse bare Newton constant) to slightly positive values\naround the transition $\\kappa_2^c$. Far above the transition $R_V$ is hard to\ncompute. This $R_V$ depends on the distance scale involved and we therefore\ninvestigate a similar explicitly $r$ dependent `running' curvature $R_{\\rm\neff}(r)$. This increases from values of order $R_V$ at intermediate distances\nto very high values at short distances. A global dimension $d$ goes from high\nvalues in the region with low $\\kappa_2$ to $d=2$ at high $\\kappa_2$. At the\ntransition $d$ is consistent with 4. We present evidence for scaling of $N'(r)$\nand introduce a scaling dimension $d_s$ which turns out to be approximately 4\nin both weak and strong coupling regions. We discuss possible implications of\nthe results, the emergence of classical euclidean spacetime and a possible\n`triviality' of the theory."
    },
    {
        "anchor": "Lattice Formulation of Two Dimensional Topological Field Theory: We investigate an integrable property and observables of 2 dimensional\nN=(4,4) topological field theory defined on a discrete lattice by using the\n\"orbifolding\" and \"deconstruction\" methods. We show that our lattice model\npossesses the integrability and the partition function reduces to matrix\nintegrals of scalar fields on sites in consequence. We make clear meaningful\ndifferences between the discrete lattice and differentiable manifold, which\nwould be important to a study of topological quantities on the lattice. We also\npropose a new construction of N=(2,2) supersymmetric lattice theory, which is\nrealized by a suitable truncation of scalar fields from the N=(4,4) theory.",
        "positive": "Smeared quasidistributions in perturbation theory: Quasi and pseudo distributions provide a new approach to determining parton\ndistribution functions (PDFs) from first principles' calculations of quantum\nchromodynamics (QCD). Here I calculate the flavor nonsinglet unpolarized quasi\ndistribution at one loop in perturbation theory, using the gradient flow to\nremove ultraviolet divergences. I demonstrate that, as expected, the gradient\nflow does not change the infrared structure of the quasi distribution at one\nloop and use the results to match the smeared matrix elements to those in the\n$\\ms$ scheme. This matching calculation is required to relate numerical results\nobtained from nonperturbative lattice QCD computations to light-front PDFs\nextracted from global analyses of experimental data."
    },
    {
        "anchor": "Casimir energy calculations within the formalism of the noncompact\n  lattice QED: A new method based on the Monte-Carlo calculation on the lattice is proposed\nto study the Casimir effect in the noncompact lattice QED. We have studied the\nstandard Casimir problem with two parallel plane surfaces (mirrors) and oblique\nboundary conditions on those as a test of our method. Physically, this boundary\nconditions may appear in the problem of modelling of the thin material films\ninteraction and are generated by additional Chern-Simons boundary term. This\napproach for the boundary condition generation is very suitable for the lattice\nformulation of the Casimir problem due to gauge invariance.",
        "positive": "Insight into the Role of Instantons and their Zero Modes from Lattice\n  QCD: Evidence from lattice QCD calculations is presented showing that instantons\nand their associated zero modes play a major role in the physics of light\nhadrons and the propagation of light quarks in the QCD vacuum."
    },
    {
        "anchor": "Chiral Gauge Theory on Lattice with Domain Wall Fermions: We investigate a U(1) lattice chiral gauge theory with domain wall fermions\nand compact gauge fixing. In the reduced model limit, our perturbative and\nnumerical investigations show that there exist no extra mirror chiral modes.\nThe longitudinal gauge degrees of freedom have no effect on the free domain\nwall fermion spectrum consisting of opposite chiral modes at the domain wall\nand at the anti-domain wall which have an exponentially damped overlap.",
        "positive": "Universality of Pattern Formation: We study a $\\mathcal PT$-symmetric scalar Euclidean field theory with a\ncomplex action, using both theoretical analysis and lattice simulations. This\nmodel has a rich phase structure that exhibits pattern formation in the\ncritical region. Analytical results and simulations associate pattern formation\nwith tachyonic instabilities in the homogeneous phase. Monte Carlo simulation\nshows that pattern morphologies vary smoothly, without distinct microphases. We\nsuggest that pattern formation in this model may be regarded as a form of\narrested spinodal decomposition. We extend our theoretical analysis to\nmulticomponent $\\mathcal PT$-symmetric Euclidean scalar field theories and show\nthat they give rise to new universality classes of local field theories that\nexhibit patterned behavior in the critical region. QCD at finite temperature\nand density is a member of the $Z(2)$ universality class when the Polyakov loop\nis used to distinguish confined and deconfined phases. This suggests the\npossibility of the formation of patterns of confined and deconfined matter in\nQCD in the critical region in the $\\mu-T$ plane."
    },
    {
        "anchor": "Discovering new physics in rare kaon decays: The decays and mixing of $K$ mesons are remarkably sensitive to the weak\ninteractions of quarks and leptons at high energies. They provide important\ntests of the standard model at both first and second order in the Fermi\nconstant $G_F$ and offer a window into possible new phenomena at energies as\nhigh as 1,000 TeV. These possibilities become even more compelling as the\ngrowing capabilities of lattice QCD make high-precision standard model\npredictions possible. Here we discuss and attempt to forecast some of these\ncapabilities.",
        "positive": "Individual complex Dirac eigenvalue distributions from random matrix\n  theory and comparison to quenched lattice QCD with a quark chemical potential: We analyze how individual eigenvalues of the QCD Dirac operator at nonzero\nquark chemical potential are distributed in the complex plane. Exact and\napproximate analytical results for both quenched and unquenched distributions\nare derived from non-Hermitian random matrix theory. When comparing these to\nquenched lattice QCD spectra close to the origin, excellent agreement is found\nfor zero and nonzero topology at several values of the quark chemical\npotential. Our analytical results are also applicable to other physical systems\nin the same symmetry class."
    },
    {
        "anchor": "Recent Results from the FASTSUM Collaboration: The FASTSUM Collaboration has developed a comprehensive research programme in\nthermal QCD using 2+1 flavour, anisotropic ensembles. In this talk, we\nsummarise some of our recent results including thermal hadron spectrum\ncalculations using our ``Generation 2L'' ensembles which have pion masses of\n239(1) MeV. These include open charm mesons and charm baryons. We also\nsummarise our work using the Backus Gilbert approach to determining the\nspectral function of the NRQCD bottomonium system. Finally, we review our\ndetermination of the interquark potential in the same system, but using our\n``Generation 2'' ensembles which have heavier pion masses of 384(4) MeV.",
        "positive": "Lattice Fermions Based on Higher-Dimensional Hyperdiamond Lattices: In this paper we generalize to higher dimensions several types of fermion\nactions on the hyperdiamond lattice including a two-parameter class of\nminimal-doubling fermions \"Creutz fermion\" and a simple fermion with sufficient\ndiscrete symmetry \"BBTW fermion\". Then it is shown that they possess some\nproperties in common with the four-dimensional case: BBTW fermions in higher\neven dimensions inevitably yield unphysical degrees of freedom. Creutz fermions\nare defined on the distorted lattices, and they lose the high discrete symmetry\nof the original lattices. We also find properties specific to the\nhigher-dimensional cases. The parameter range for Creutz action to yield\nminimal-doubling and physical fermions becomes narrower with the dimension\ngetting higher, thus it becomes more and more difficult to realize\nminimal-doubling. In addition, we generalize the subspecies of Creutz and BBTW\nactions including a new class of minimal-doubling actions \"Appended Creutz\naction\"."
    },
    {
        "anchor": "Lattice QCD and the Balkan physicists contribution: This is a paper based on the invited talk the author gave at the 9th Balkan\nPhysical Union conference. It contains some of the main achievements of lattice\nQCD simulations followed by a list of Balkan physicists who have contributed to\nthe project.",
        "positive": "A study of the eta and eta' mesons with improved staggered fermions: We report on a high statistics lattice QCD calculation of the mass of the eta\nand eta' mesons using ASQTAD improved staggered fermions. The calculation used\ntwo ensembles with different lattice spacings and pion masses. We also report\nresults for eta-eta' mixing. The results are in satisfactory agreement with\nother lattice calculations using other fermion formulations and with\nexperiment, given the the unphysical quark masses used. We see no evidence of\nabnormal behaviour at the lattice spacings studied."
    },
    {
        "anchor": "Efficient Cluster Algorithm for CP(N-1) Models: Despite several attempts, no efficient cluster algorithm has been constructed\nfor CP(N-1) models in the standard Wilson formulation of lattice field theory.\nIn fact, there is a no-go theorem that prevents the construction of an\nefficient Wolff-type embedding algorithm. In this paper, we construct an\nefficient cluster algorithm for ferromagnetic SU(N)-symmetric quantum spin\nsystems. Such systems provide a regularization for CP(N-1) models in the\nframework of D-theory. We present detailed studies of the autocorrelations and\nfind a dynamical critical exponent that is consistent with z = 0.",
        "positive": "Lattice QCD Simulations in External Background Fields: We discuss recent results and future prospects regarding the investigation,\nby lattice simulations, of the non-perturbative properties of QCD and of its\nphase diagram in presence of magnetic or chromomagnetic background fields.\nAfter a brief introduction to the formulation of lattice QCD in presence of\nexternal fields, we focus on studies regarding the effects of external fields\non chiral symmetry breaking, on its restoration at finite temperature and on\ndeconfinement. We conclude with a few comments regarding the effects of\nelectromagnetic background fields on gluodynamics."
    },
    {
        "anchor": "Meson interactions at large $N_c$ from Lattice QCD: We report on the computation of the scaling of QCD observables with the\nnumber of colours, $N_c$. For this, we use dynamical configurations with four\nactive flavours, $N_f=4$, and values of $N_c=3-6$. We study the meson masses\nand decay constants, and compute the leading and subleading contributions to\nthe Low Energy Constants (LECs) of the chiral Lagrangian. We also explore $\\pi\n\\pi$ scattering in the $I=2$ channel, and compute the $K \\to \\pi $ weak decay\nmatrix elements. We comment on the relation of the latter to $K \\to \\pi\\pi$\nprocesses and the $\\Delta I=1/2$ rule.",
        "positive": "Finite volume scaling of the electro-magnetic pion form factor in the\n  $\u03b5$ regime: We consider finite volume effects on the electro-magnetic pion form factor\nnear the chiral limit, in the so-called $\\epsilon$ regime. The\npseudoscalar-vector-pseudoscalar three-point function is calculated in the\n$\\epsilon$ expansion of chiral perturbation theory to the next-to-leading\norder. In the $\\epsilon$ regime, finite volume effects are non-perturbatively\nlarge in general. However, we find a way to remove its dominant part, by\ninserting momenta to the correlators, and taking an appropriate ratio of them.\nThe subleading contribution is, then, shown to be perturbatively small, and one\ncan extract the form factor as in a similar way to that in the $p$ regime."
    },
    {
        "anchor": "Progress in three-particle scattering from LQCD: We present the status of our formalism for extracting three-particle\nscattering observables from lattice QCD (LQCD). The method relies on relating\nthe discrete finite-volume spectrum of a quantum field theory with its\nscattering amplitudes. As the finite-volume spectrum can be directly determined\nin LQCD, this provides a method for determining scattering observables, and\nassociated resonance properties, from the underlying theory. In a pair of\npapers published over the last two years, two of us have extended this approach\nto apply to relativistic three-particle scattering states. In this talk we\nsummarize recent progress in checking and further extending this result. We\ndescribe an extension of the formalism to include systems in which two-to-three\ntransitions can occur. We then present a check of the previously published\nformalism, in which we reproduce the known finite-volume energy shift of a\nthree-particle bound state.",
        "positive": "The hadronic vacuum polarization with twisted boundary conditions: The leading-order hadronic contribution to the anomalous magnetic moment of\nthe muon is given by a weighted integral over the subtracted hadronic vacuum\npolarization. This integral is dominated by euclidean momenta of order the muon\nmass which are not available on current lattice volumes with periodic boundary\nconditions. Twisted boundary conditions can in principle help access momenta of\nany size even in a finite volume. We investigate the implementation of twisted\nboundary conditions both numerically (using all-mode averaging for improved\nstatistics) and analytically, and present our initial results."
    },
    {
        "anchor": "Universal scaling and the asymptotic behaviour of Fourier coefficients\n  of the baryon-number density in QCD: We discuss the scaling of the Yang-Lee singularity (YLs) and show how the\nuniversal scaling can be used to locate phase transitions in QCD. We describe\ntwo complementary methods to extract the location of the Yang-Lee singularity\nfrom lattice QCD data of the baryon-number density and higher order cumulants\nof the baryon number, obtained at imaginary chemical potential. The first\nmethod (multi-point Pad\\'e resummation) is used to determine the Roberge-Weiss\nphase transition temperature. Our continuum extrapolated result is\n$T_{RW}=211.1\\pm3.1$ MeV. The second method is based on the asymptotic\nbehaviour of the Fourier coefficients of the baryon-number density. We discuss\nthe derivation of a fitting function and demonstrate that the procedure can\nsuccessfully locate the YLs in the Quark Meson model.",
        "positive": "The running of the bare coupling in SU(N) gauge theories: For N>4 there is a first order bulk transition that cleanly separates the\nstrong and weak coupling regimes of SU(N) lattice gauge theories with the\nplaquette action. We find that in this case the calculated string tension can\nbe readily fitted throughout the weak coupling region by a standard 3-loop\nperturbative expression modified by lattice spacing corrections of the expected\nform. While our fits demand the presence of the latter, they are not\nconstraining enough to tell us which of the various bare coupling schemes is a\n`good' one, in the sense that terms in the beta-function beyond 3-loops are\nindeed negligible (in the relevant range of scales). To resolve this ambiguity\nwe work in SU(3), using the Schrodinger Functional coupling scheme as a\nbenchmark, and find that the Parisi mean-field improved coupling scheme matches\nit very well. Using the latter scheme, we have fitted the values of the string\ntension that have been calculated for SU(3) to SU(8), to obtain\nLambda_MSbar/sqrt(sigma) = 0.503(2)(40) + 0.33(3)(3)/N**2, where the first\nerror is statistical and the second is our estimate of the systematic error\nfrom all sources."
    },
    {
        "anchor": "Lattice QCD equation of state : improving the differential method: We propose an improvement of the differential method for the computation of\nthe equation of state of QCD from lattice simulations. In contrast to the\nearlier differential method our technique yields positive pressure for all\ntemperatures including in the transition region. Employing it on temporal\nlattices of 8, 10 and 12 sites and by extrapolating to zero lattice spacing we\nobtained the pressure, energy density, entropy density, specific heat and speed\nof sound in quenched QCD for 0.9 < T/Tc < 3. A comparison of our results is\nmade with those from the dimensional reduction approach and a conformal\nsymmetric theory at high-temperature.",
        "positive": "The Continuum Limit of Non Compact QED: Since four-fermion operators in strongly coupled $QED$ are nonperturbatively\nrenormalizable, we analyze here the phase diagram and critical behaviour of the\nGauged Nambu-Jona Lasinio model. Our mean field approximation relates the\ncritical exponents along the continuous phase transition line with the mass\ndependence of the chiral condensate in the Coulomb phase of standard noncompact\n$QED$. The numerical results for noncompact $QED$ strongly suggest non mean\nfield exponents along the critical line."
    },
    {
        "anchor": "In-medium modifications of open and hidden strange-charm mesons from\n  spatial correlation functions: We calculate spatial correlation functions of in-medium mesons consisting of\nstrange--anti-strange, strange--anti-charm and charm--anti-charm quarks in\n(2+1)-flavor lattice QCD using the highly improved staggered quark action. A\ncomparative study of the in-medium modifications of mesons with different\nflavor contents is performed. We observe significant in-medium modifications\nfor the $\\phi$ and $D_s$ meson channels already at temperatures around the\nchiral crossover region. On the other hand, for the $J/\\psi$ and $\\eta_c$ meson\nchannels in-medium modifications remain relatively small around the chiral\ncrossover region and become significant only above 1.3 times the chiral\ncrossover temperature.",
        "positive": "Calculation of the decay width of decuplet baryons: We calculate the coupling constant and decay width of the decuplet to octet\nbaryon transitions in lattice QCD using the transfer matrix method. The\ntransition amplitude is related to the coupling constant and via the Fermi's\nGolden Rule to the decay width. The method is applicable for near-degeneracy of\nthe energy levels of initial and final states and, when this condition is\nfulfilled, yields a good estimate of the decay width. We present results using\na hybrid action with domain wall valence quarks on a staggered sea with $350$\nMeV pion mass as well as for a domain wall fermion action with $180$ MeV pion\nmass. We find $\\Gamma\\left( \\Delta \\to \\pi\\,N \\right) = 119\\,( 8)\\,( 8)$ MeV\nfor the transition of Delta to pion-nucleon within the unitary domain wall\nsetup. We also report values for the decay widths of the $\\Sigma^*$ and $\\Xi*$\nbaryons."
    },
    {
        "anchor": "Phase structure of lattice QCD at finite temperature for 2+1 flavors of\n  Kogut-Susskind quarks: We report on a study of the finite-temperature chiral transition on an\n$N_t=4$ lattice for 2+1 flavors of Kogut-Susskind quarks. We find the point of\nphysical quark masses to lie in the region of crossover, in agreement with\nresults of previous studies. Results of a detailed examination of the\n$m_{u,d}=m_s$ case indicate vanishing of the screening mass of $\\sigma$ meson\nat the end point of the first-order transition.",
        "positive": "A lattice study of N=2 Landau-Ginzburg model using a Nicolai map: It has been conjectured that the two-dimensional N=2 Wess-Zumino model with a\nquasi-homogeneous superpotential provides the Landau-Ginzburg description of\nthe N=2 superconformal minimal models. For the cubic superpotential W=(lambda)\nPhi^3/3, it is expected that the Wess-Zumino model describes A_{2} model and\nthe chiral superfield Phi shows the conformal weight (h,bar{h})=(1/6,1/6) at\nthe IR fixed point. We study this conjecture by a lattice simulation,\nextracting the weight from the finite volume scaling of the susceptibility of\nthe scalar component in Phi. We adopt a lattice model with the overlap fermion,\nwhich possesses a Nicolai map and a discrete R-symmetry. We set a(lambda)=0.3\nand generate the scalar field configurations by solving the Nicolai map on L\ntimes L lattices in the range L=18 - 32. To solve the map, we use the\nNewton-Raphson algorithm with various initial configurations. The result is\n1-h-bar{h}=0.660 \\pm0.011, which is consistent with the conjecture within the\nstatistical error, while a systematic error is estimated as less than 0.5 %."
    },
    {
        "anchor": "Rare $B$ decays using lattice QCD form factors: In this write-up we review and update our recent lattice QCD calculation of\n$B \\to K^*$, $B_s \\to \\phi$, and $B_s \\to K^*$ form factors [arXiv:1310.3722].\nThese unquenched calculations, performed in the low-recoil kinematic regime,\nprovide a significant improvement over the use of extrapolated light cone sum\nrule results. The fits presented here include further kinematic constraints and\nestimates of additional correlations between the different form factor shape\nparameters. We use these form factors along with Standard Model determinations\nof Wilson coefficients to give Standard Model predictions for several\nobservables [arXiv:1310.3887]. The modest improvements to the form factor fits\nlead to improved determinations of $F_L$, the fraction of longitudinally\npolarized vector mesons, but have little effect on most other observables.",
        "positive": "Non-perturbative determination of improvement coefficients b_m and\n  b_A-b_P and normalisation factor Z_m*Z_P/Z_A with N_f=3 Wilson fermions: We determine non-perturbatively the normalisation constant Z_m*Z_P/Z_A as\nwell as the Symanzik coefficients b_m and b_A-b_P, required in O(a) improved\nquark mass renormalisation with Wilson fermions. The strategy underlying their\ncomputation involves simulations in N_f=3 QCD with O(a) improved massless sea\nand non-degenerate valence quarks in the finite-volume Schroedinger functional\nscheme. Our results, which cover the typical gauge coupling range of\nlarge-volume N_f=2+1 QCD simulations with Wilson fermions at lattice spacings\nbelow 0.1 fm, are of particular use for the non-perturbative calculation of\nO(a) improved renormalised quark masses."
    },
    {
        "anchor": "Heavy quark diffusion coefficient with gradient flow: The heavy quark diffusion coefficient is encoded in the spectral functions of\nthe chromo-electric and the chromo-magnetic correlators, of which the latter\ndescribes the T/M contribution. We study these correlators at two different\ntemperatures $T=1.5T_c$ and $T=10^4T_c$ in the deconfined phase of SU(3) gauge\ntheory. We use gradient flow for noise reduction. We perform both continuum and\nzero flow time limits to extract the heavy quark diffusion coefficient. Our\nresults imply that the mass suppressed effects in the heavy quark diffusion\ncoefficient are 20% for bottom quarks and 34% for charm quark at $T=1.5T_c$.",
        "positive": "First results of ETMC simulations with Nf=2+1+1 maximally twisted mass\n  fermions: We present first results from runs performed with Nf=2+1+1 flavours of\ndynamical twisted mass fermions at maximal twist: a degenerate light doublet\nand a mass split heavy doublet. An overview of the input parameters and tuning\nstatus of our ensembles is given, together with a comparison with results\nobtained with Nf=2 flavours. The problem of extracting the mass of the K- and\nD-mesons is discussed, and the tuning of the strange and charm quark masses\nexamined. Finally we compare two methods of extracting the lattice spacings to\ncheck the consistency of our data and we present some first results of ChiPT\nfits in the light meson sector."
    },
    {
        "anchor": "Electric Polarizability of Neutral Hadrons from Lattice QCD: By simulating a uniform electric field on a lattice and measuring the change\nin the rest mass, we calculate the electric polarizability of neutral mesons\nand baryons using the methods of quenched lattice QCD. Specifically, we measure\nthe electric polarizability coefficient from the quadratic response to the\nelectric field for 10 particles: the vector mesons $\\rho^0$ and $K^{*0}$; the\noctet baryons n, $\\Sigma^0$, $\\Lambda_{o}^{0}$, $\\Lambda_{s}^{0}$, and $\\Xi^0$;\nand the decouplet baryons $\\Delta^0$, $\\Sigma^{*0}$, and $\\Xi^{*0}$.\nIndependent calculations using two fermion actions were done for consistency\nand comparison purposes. One calculation uses Wilson fermions with a lattice\nspacing of $a=0.10 $fm. The other uses tadpole improved L\\\"usher-Weiss gauge\nfields and clover quark action with a lattice spacing $a=0.17 $fm. Our results\nfor neutron electric polarizability are compared to experiment.",
        "positive": "Chemical potential on the lattice: Universal or Unique?: Lattice techniques are the most reliable ones to investigate non-perturbative\naspects of quantum chromodynamics (QCD) such as its phase diagram in the\ntemperature-baryon density plane. They are, however, well-known to be beset\nwith a variety of problems as one increases the density. We address here the\nold question of placing the baryonic (quark) chemical potential on the lattice.\nWe point out that it may have important consequences for the current and future\nexperimental searches of QCD critical point."
    },
    {
        "anchor": "Phase diagram of the lattice Wess-Zumino model from rigorous lower\n  bounds on the energy: We study the lattice N=1 Wess-Zumino model in two dimensions and we construct\na sequence $\\rho^{(L)}$ of exact lower bounds on its ground state energy\ndensity $\\rho$, converging to $\\rho$ in the limit $L\\to\\infty$. The bounds\n$\\rho^{(L)}$ can be computed numerically on a finite lattice with $L$ sites and\ncan be exploited to discuss dynamical symmetry breaking. The transition point\nis determined and compared with recent results based on large-scale Green\nFunction Monte Carlo simulations with good agreement.",
        "positive": "Determining the mass anomalous dimension through the eigenmodes of Dirac\n  operator: We define a scale-dependent effective mass anomalous dimension from the\nscaling of the mode number of the massless Dirac operator, which connects the\nperturbative $\\gamma_m$ of an asymptotically-free system to the universal\n$\\gamma_m^{\\star}$ at a conformal fixed point. We use a stochastic algorithm to\nmeasure the mode number up to the cutoff scale on lattices as large as $48^4$.\nFocusing on SU(3) lattice gauge theory with $N_f = 12$ massless fundamental\nfermions, we examine systematic effects due to finite volumes and non-zero\nfermion masses. Our results suggest the existence of an infrared fixed point\nwith $\\gamma_m^{\\star} \\approx 0.25$. Our method provides a unique probe to\nstudy systems from the UV to the IR. It is universal and can be applied to any\nlattice model of interest, including both chirally-broken and IR-conformal\nsystems."
    },
    {
        "anchor": "Linking confinement to spectral properties of the Dirac operator: We represent Polyakov loops and their correlators as spectral sums of\neigenvalues and eigenmodes of the lattice Dirac operator. The deconfinement\ntransition of pure gauge theory is characterized as a change in the response of\nmoments of eigenvalues to varying the boundary conditions of the Dirac\noperator. We argue that the potential between static quarks is linked to\nspatial correlations of Dirac eigenvectors.",
        "positive": "Deconfinement and non-zero baryon density: I discuss a few issues related with deconfinement at finite baryon density by\nconsidering lattice results for two colors QCD and ``toy'' studies of three\ncolors QCD."
    },
    {
        "anchor": "Two-dimensional lattice for four-dimensional N=4 supersymmetric\n  Yang-Mills: We construct a lattice formulation of a mass-deformed two-dimensional N=(8,8)\nsuper Yang-Mills theory with preserving two supercharges exactly. Gauge fields\nare represented by compact unitary link variables, and the exact supercharges\non the lattice are nilpotent up to gauge transformations and SU(2)_R rotations.\nDue to the mass deformation, the lattice model is free from the vacuum\ndegeneracy problem, which was encountered in earlier approaches, and flat\ndirections of scalar fields are stabilized giving discrete minima representing\nfuzzy S^2. Around the trivial minimum, quantum continuum theory is obtained\nwith no tuning, which serves a nonperturbative construction of the IIA matrix\nstring theory. Moreover, around the minimum of k-coincident fuzzy spheres,\nfour-dimensional N=4 U(k) super Yang-Mills theory with two commutative and two\nnoncommutative directions emerges. In this theory, sixteen supersymmetries are\nbroken by the mass deformation to two. Assuming the breaking is soft, we give a\nscenario leading to undeformed N=4 super Yang-Mills on R^4 without any fine\ntuning. As an evidence for the validity of the assumption, some computation of\n1-loop radiative corrections is presented.",
        "positive": "Polarized structure functions from the lattice: We give a brief sketch of lattice structure function calculations and review\nprevious results for the axial coupling $g_A$. We outline a new technique for\ntreating fermions on the lattice that preserves chiral symmetry, domain wall\nfermions. Finally, we give preliminary results for the nucleon spectrum using\nthis new technique. Remarkably, a large mass splitting between the $N$ and\n$N^*$, roughly consistent with experiment, is produced in the calculation.\nThese results are encouraging for proposed calculations of nucleon structure\nfunctions."
    },
    {
        "anchor": "Lattice QCD in rotating frames: We formulate lattice QCD in rotating frames to study the physics of QCD\nmatter under rotation. We construct the lattice QCD action with the rotational\nmetric and apply it to the Monte Carlo simulation. As the first application, we\ncalculate the angular momenta of gluons and quarks in the rotating QCD vacuum.\nThis new framework is useful to analyze various rotation-related phenomena in\nQCD.",
        "positive": "Comparison of SO(3) and SU(2) lattice gauge theory: The Villain form of SO(3) lattice gauge theory is studied and compared to\nWilson's SU(2) theory. The topological invariants in SO(3) which correspond to\ntwisted boundary conditions in SU(2) are discussed and lattice observables are\nintroduced for them. An apparent SO(3) phase with negative adjoint Polyakov\nloop is explained in terms of these observables. The electric twist free\nenergy, an order parameter for the confinement-deconfinement transition, is\nmeasured in both theories to calibrate the temperature. The results indicate\nthat lattices with about 700^4 sites or larger will be needed to study the\nSO(3) confined phase. Alternative actions are discussed and an analytic path\nconnecting SO(3) and SU(2) lattice gauge theory at weak coupling is exhibited.\nThe relevance for confinement of the centre of the gauge group is discussed."
    },
    {
        "anchor": "Reducing Discretization Errors in Lattice QCD Spectroscopy: The improved Wilson quark action - the clover action - is constructed to have\nsmaller discretization errors than the normal Wilson quark action. We test this\nin a quenched spectroscopy computation on 6 lattice ensembles with spacings\nfrom 0.15 to 0.43 fm. To ensure that the dominant scaling violations come from\nthe fermions we use an $O(a^2)$ improved 6-link $SU(3)$ pure gauge action. We\nfind evidence that fermionic scaling violations are consistent with $O(a^2)$\nfor clover fermions and $O(a)$ with a nonnegligible $O(a^2)$ term for standard\nWilson fermions. This latter mixed ansatz makes a reliable continuum\nextrapolation problematic for Wilson fermions. For clover fermions, on the\nother hand, we obtain accurate predictions for hadron masses in quenched\ncontinuum QCD. We find that the slopes of the scaling violations are roughly\n200 MeV for both Wilson and clover fermions.",
        "positive": "Partially quenched chiral perturbation theory in the epsilon regime at\n  next-to-leading order: We calculate the partition function of partially quenched chiral perturbation\ntheory in the epsilon regime at next-to-leading order using the supersymmetry\nmethod in the formulation without a singlet particle. We include a nonzero\nimaginary chemical potential and show that the finite-volume corrections to the\nlow-energy constants $\\Sigma$ and $F$ for the partially quenched partition\nfunction, and hence for spectral correlation functions of the Dirac operator,\nare the same as for the unquenched partition function. We briefly comment on\nhow to minimize these corrections in lattice simulations of QCD. As a side\nresult, we show that the zero-momentum integral in the formulation without a\nsinglet particle agrees with previous results from random matrix theory."
    },
    {
        "anchor": "Running couplings in equivariantly gauge-fixed SU(N) Yang--Mills\n  theories: In equivariantly gauge-fixed SU(N) Yang--Mills theories, the gauge symmetry\nis only partially fixed, leaving a subgroup $H\\subset SU(N)$ unfixed. Such\ntheories avoid Neuberger's nogo theorem if the subgroup $H$ contains at least\nthe Cartan subgroup $U(1)^{N-1}$, and they are thus non-perturbatively well\ndefined if regulated on a finite lattice. We calculate the one-loop beta\nfunction for the coupling $\\tilde{g}^2=\\xi g^2$, where $g$ is the gauge\ncoupling and $\\xi$ is the gauge parameter, for a class of subgroups including\nthe cases that $H=U(1)^{N-1}$ or $H=SU(M)\\times SU(N-M)\\times U(1)$. The\ncoupling $\\tilde{g}$ represents the strength of the interaction of the gauge\ndegrees of freedom associated with the coset $SU(N)/H$. We find that\n$\\tilde{g}$, like $g$, is asymptotically free. We solve the\nrenormalization-group equations for the running of the couplings $g$ and\n$\\tilde{g}$, and find that dimensional transmutation takes place also for the\ncoupling $\\tilde{g}$, generating a scale $\\tilde{\\Lambda}$ which can be larger\nthan or equal to the scale $\\Lambda$ associated with the gauge coupling $g$,\nbut not smaller. We speculate on the possible implications of these results.",
        "positive": "Double parton distributions in the nucleon on the lattice: Flavor\n  interference effects: Information about double parton distributions (DPDs) can be obtained by\ncalculating four-point functions on the lattice. We continue our study on the\nfirst DPD Mellin moment of the unpolarized proton by considering interference\neffects w.r.t. the quark flavor. In our simulation we employ an $n_f = 2 + 1$\nensemble with inverse coupling $\\beta = 3.4$, and pseudoscalar masses of $m_\\pi\n= 355~\\mathrm{MeV}$ and $m_K = 441~\\mathrm{MeV}$. The results are converted to\nthe $\\overline{\\mathrm{MS}}$-scheme at the scale $\\mu = 2~\\mathrm{GeV}$. We\nanalyze the dependence of the considered Mellin moments on the quark\npolarization and compare our results with quark model predictions."
    },
    {
        "anchor": "A Lattice Study of Semi-leptonic Decays of $D$-Mesons: We present results of a lattice computation of the matrix elements of the\nvector and axial-vector currents which are relevant for the semi-leptonic\ndecays $D \\rightarrow K$ and $D \\rightarrow K^*$. The computations are\nperformed in the quenched approximation to lattice QCD on a $24^3 \\times 48$\nlattice at $\\beta=6.2$ using an $O(a)$-improved fermionic action.",
        "positive": "On the $\u03b2$- and quark mass dependence of the nuclear transition in\n  the strong coupling regime: Lattice QCD in a dual formulation with staggered fermions is well established\nin the strong coupling limit and allows to perform Monte Carlo simulations at\nfinite baryon chemical potential. We have recently addressed the dependence of\nthe nuclear critical end point as a function of the quark mass $am_q$, and\nseparately as a function of the lattice gauge coupling $\\beta$ in the chiral\nlimit. Here we proceed to determine the dependence of the nuclear transition on\nboth, $am_q$ and $\\beta$, on isotropic lattices and attempt to pinpoint the\ncritical end point for various $\\beta$ where the sign problem is still\nmanageable."
    },
    {
        "anchor": "Nucleon isovector form factors from domain-wall lattice QCD at the\n  physical mass: The current status of lattice-QCD numerical calculations by joint LHP, RBC,\nand UKQCD collaborations of nucleon isovector vector- and axialvector-current\nform factors using a 2+1-flavor dynamical domain-wall fermions lattice QCD\nensemble generated jointly by RBC and UKQCD collaborations are presented. The\nlattice spacing is set at about 0.1141(3) fm, and the lattice spatial extent is\n48 spacings or about 5.4750(14) fm. The strange and degenerate up and down\nquark mass values are set at their essentially physical values to provide the\nphysical $\\Omega$ mass and a degenerate pion mass of 0.1392(2) GeV. Our nucleon\nmass estimate is about 0.947(6) GeV. Possible excited-state contaminations in\nthe calculated vector- and axialvector-current form factors are hidden below\nlarger statistical noises. The numerical details of the form-factor shape\nparameters, such as the mean squared radii, the anomalous magnetic moment, or\nthe pseudoscalar coupling extracted from the form factors, are described, along\nwith comparisons of different approaches used to extract them.",
        "positive": "Perturbatively improving RI-MOM renormalization constants: The determination of renormalization factors is of crucial importance in\nlattice QCD. They relate the observables obtained on the lattice to their\nmeasured counterparts in the continuum in a suitable renormalization scheme.\nTherefore, they have to be computed as precisely as possible. A widely used\napproach is the nonperturbative Rome-Southampton method. It requires, however,\na careful treatment of lattice artifacts. In this paper we investigate a method\nto suppress these artifacts by subtracting one-loop contributions to\nrenormalization factors calculated in lattice perturbation theory. We compare\nresults obtained from a complete one-loop subtraction with those calculated for\na subtraction of contributions proportional to the square of the lattice\nspacing."
    },
    {
        "anchor": "Mass anomalous dimension in sextet QCD: We extend our previous study of the SU(3) gauge theory with N_f=2 flavors of\nfermions in the sextet representation of color. Our tool is the Schroedinger\nfunctional method. By changing the lattice action, we push the bulk transition\nof the lattice theory to stronger couplings and thus reveal the beta function\nand the mass anomalous dimension gamma_m over a wider range of coupling, out to\ng^2 ~ 11. Our results are consistent with an infrared fixed point, but walking\nis not ruled out. Our main result is that gamma_m never exceeds 0.45, making\nthe model unsuitable for walking technicolor. We use a novel method of\nextrapolation to the large-volume/continuum limit, tailored to near-conformal\ntheories.",
        "positive": "Large-scale simulations with chiral symmetry: We carry out a comparative study among five-dimensional formulations of\nchirally symmetric fermions about the algorithmic performance, chiral symmetry\nviolation and topological tunneling to find a computationally inexpensive\nformulation with good chiral symmetry. With our choice of the lattice action,\nwe have launched large-scale simulations on fine lattices aiming at a precision\nstudy of light and heavy quark physics. We report on the comparative study,\ncurrent status of the large-scale simulations, and preliminary results on the\nresidual quark mass and auto-correlation."
    },
    {
        "anchor": "Probing parity doubling in nucleons at high temperature: The spectrum of nucleons and their parity partners is studied as a function\nof temperature spanning the deconfinement transition. We analyse our results\nusing the correlation functions directly, exponential fits in the hadronic\nphase, and the Maximum Entropy Method. These techniques all indicate that there\nis degeneracy in the parity partners' channels in the deconfined phase. This is\nin accordance with the expectation that there is parity doubling and chiral\nsymmetry in the deconfined phase. In the hadronic phase, we also find that the\nnucleon ground state is largely independent of temperature, whereas there are\nsubstantial temperature effects in the negative parity channel. All results are\nobtained using our FASTSUM 2+1 flavour ensembles.",
        "positive": "Analysis of topological structure of the QCD vacuum with overlap-Dirac\n  operator eigenmode: Using the eigenmodes of the overlap-Dirac operator, we study the topological\nstructure of the QCD vacuum. We investigate the space-time profile of the\nlow-lying eigenmodes and their contribution to the vacuum action density and\nchiral condensate under the existence of static color sources. We demonstrate\nthat the low-lying Dirac eigenmode shows the flux-tube structure, which\nsuggests the relevance to confinement. We also analyze the chiral condensate in\nthe flux-tube. Chiral symmetry is partially restored inside the flux, and the\nreduction of the condensate is about 20% at the center of the tube."
    },
    {
        "anchor": "QCD, Supersymmetric QCD, Lattice QCD and String Theory: Synthesis on the\n  Horizon?: Supersymmetric gauge theories in four dimensions have taught us many\nimportant physics lessons. These can both inform and be informed by future work\non the lattice. I focus on three issues: the properties of supersymmetric\nYang-Mills theory and its relation to the non-supersymmetric case; the\nproperties of gauge theories with matter and their relation to real QCD; and,\nbriefly, the recent discovery that gauge theories and string theories are more\ndeeply connected than ever previously realized. Specific questions for lattice\ngauge theorists to consider are raised in the context of the first two topics.",
        "positive": "A New Approach of Fermion Field on Lattice: A new approach to formulate the fermion field on lattice is introduced by\nproposing a new Dirac operator on lattice.This approach can eliminate the\nFermion doubling problem, preserve the chiral symmetry and get the same\ndispersion relation for both Fermion and Boson fields.Then the Weinberg-Salam\nmodel on lattice may be formulated in this approach."
    },
    {
        "anchor": "QCD vacuum and confinement: This course consists of two lectures. In the first lecture I discuss why a\nnon perturbative formulation of QCD is needed, and I show that lattice\nformulation copes with this need, even if it mainly produces numerical results.\nIn the second lecture I discuss how lattice can help to understand the\ndeconfinement transition.Such understanding is also important to predict\nparameters that can help in the interpretation of heavy ions high energy\nexperiments.",
        "positive": "Infrared fixed point of SU(2) gauge theory with six flavors: We compute the running of the coupling in SU(2) gauge theory with six\nfermions in fundamental representation of the gauge group. We establish an\ninfrared stable fixed point at strong coupling and measure also the anomalous\ndimension of the fermion mass operator at the fixed point. This theory\ntherefore likely lies close to the boundary of the conformal window and will\ndisplay novel infrared dynamics if coupled with the electroweak sector of the\nStandard Model."
    },
    {
        "anchor": "Perturbative analysis of the Neuberger-Dirac operator in the\n  Schr\u00f6dinger functional: We investigate the spectrum of the free Neuberger-Dirac operator $\\Dov$ on\nthe Schr\\\"odinger functional (SF). We check that the lowest few eigen-values of\nthe Hermitian operator $\\Dov^{\\dag}\\Dov$ in unit of $L^{-2}$ converge to the\ncontinuum limit properly. We also perform a one-loop calculation of the SF\ncoupling, and then check the universality and investigate lattice artifacts of\nthe step scaling function. It turns out that the lattice artifacts for the\nNeuberger-Dirac operator are comparable in those of the clover action.",
        "positive": "On Nambu Monopole Dynamics in the SU(2) Lattice Higgs Model: It is shown that the SU(2) Higgs model on a lattice is equivalent to the\nGeorgi--Glashow model in the limit of a small coupling constant between the\nHiggs and gauge fields. It can therefore be concluded that the transition\nbetween the confinement and symmetric phases in the 3+1 dimensional SU(2) Higgs\nmodel at finite temperature is accompanied by condensation of Nambu monopoles."
    },
    {
        "anchor": "Pion masses in 2-flavor QCD with $\u03b7$ condensation: We investigate the 2-flavor QCD with non-degenerate quark masses at\nlow-energy, using the chiral perturbation theory including the $\\eta$ meson and\nanomaly effects. For the fixed $m_d\\not=0$, the neutral pion becomes massless\nat two values of $m_u$, between which a spontaneously CP broken phase appears\nwith the neutral pion condensation. We then show that the topological\nsusceptibility diverges at these two critical points. We also consider the case\nof $m_u=m_d$ but $\\theta=\\pi$, equivalently $m_u= - m_d$ with $\\theta = 0$ by\nthe chiral rotation and show that the CP symmetry is spontaneously broken by\nthe $\\eta$ condensation at small $m$. Around $m=0$, three pions become\nNambu-Goldstone modes, showing non-standard behavior that $m_\\pi^2 = O(m^2)$,\nwhich, however, is consistent with the chiral Ward-Takahashi identities.}",
        "positive": "The Large $N_c$ limit of QCD on the lattice: We review recent progress in the study of the large $N_c$ limit of gauge\ntheories from lattice simulations. The focus is not only the planar limit but\nalso the size of ${\\mathcal O}(N_c^{-1})$ corrections for values of $N_c\\gtrsim\n3$. Some concrete examples of the topics we include are tests of large-$N_c$\nfactorization, the topological susceptibility, the glueball, meson and baryon\nspectra, the chiral dependence of masses and decay constants, and weak matrix\nelements related to the $\\Delta I=1/2$ rule in kaon decays."
    },
    {
        "anchor": "Strong coupling constant from moments of quarkonium correlators: I review the determination of the strong coupling constant from moments of\nquarkonium correlators calculated on the lattice. I discuss different sources\nof systematic errors in such calculations.",
        "positive": "Analytic expansions of two- and three-particle excited-state energies: The last years have seen significant developments in methods relating two-\nand three-particle finite-volume energies to scattering observables. These\nrelations hold for both weakly and strongly interacting systems, and studying\ntheir predictions in limiting cases can provide important cross checks as well\nas giving useful insights into the general formulae. In these proceedings, we\npresent analytic results for finite-volume excited states, recovered by\nexpanding the general relations in powers of the interaction strength. We\nhighlight elegant patterns that emerge, especially for excited three-particle\nenergies, and discuss various applications of the results. The two-particle\nresults summarized here are described in more detail in the full manuscript,\nand the three-particle results are detailed in a manuscript to appear."
    },
    {
        "anchor": "Topology at zero and finite T in SU(2) Yang-Mills theory: We determine the topological susceptibility \\chi at T=0 and its behaviour at\nfinite T across the deconfining transition in pure SU(2) gauge theory. We use\nan improved topological charge density operator. \\chi goes to zero above T_c,\nbut more slowly than in SU(3) gauge theory.",
        "positive": "Degenerate distributions in complex Langevin dynamics: one-dimensional\n  QCD at finite chemical potential: We demonstrate analytically that complex Langevin dynamics can solve the sign\nproblem in one-dimensional QCD in the thermodynamic limit. In particular, it is\nshown that the contributions from the complex and highly oscillating spectral\ndensity of the Dirac operator to the chiral condensate are taken into account\ncorrectly. We find an infinite number of classical fixed points of the Langevin\nflow in the thermodynamic limit. The correct solution originates from a\ncontinuum of degenerate distributions in the complexified space."
    },
    {
        "anchor": "First study of the three-gluon static potential in Lattice QCD: We estimate the potential energy for a system of three static gluons in\nLattice QCD. This is relevant for the different models of three-body glueballs\nhave been proposed in the literature, either for gluons with a constituent\nmass, or for massless ones. A Wilson loop adequate to the static hybrid\nthree-body system is developed. We study different spacial geometries, to\ncompare the starfish model with the triangle model, for the three-gluon\npotential. We also study two different colour structures, symmetric and\nantisymmetric, and compare the respective static potentials. A first simulation\nis performed in a $24^3 \\times 48$ periodic Lattice, with $\\beta=6.2$ and $a\n\\sim 0.072$ fm.",
        "positive": "Extracting three-body observables from finite-volume quantities: Scattering and transition amplitudes with three-hadron final states play an\nimportant role in nuclear and particle physics. However, predicting such\nquantities using numerical Lattice QCD is very difficult, in part because of\nthe effects of Euclidean time and finite volume. In this review we highlight\nrecent formal developments that work towards overcoming these issues. We\norganize the presentation into three parts: large volume expansions,\nnon-relativistic nonperturbative analyses, and nonperturbative studies based in\nrelativistic field theory.\n  In the first part we discuss results for ground state energies and matrix\nelements given by expanding in inverse box length, $1/L$. We describe\ncomplications that arise at $\\mathcal O(1/L^6)$ and include a table summarizing\nthe results of different calculations.\n  In the second part we summarize three recent non-relativistic\nnon-perturbative studies and highlight the main conclusions of these works.\nThis includes demonstrating that the three-particle finite-volume spectrum is\ndetermined, up to exponentially suppressed effects, by on-shell amplitudes, as\nwell as recovering a finite-volume quantization condition for scattering a\nstable particle off a two-particle bound state. In this part we also highlight\nrecent work concerning a three-particle bound state in a finite volume.\n  In the third and final part, we review recent work based in non-perturbative\nrelativistic field theory. Here the finite-volume spectrum has been related to\nan intermediate infinite-volume quantity which itself is related via a known\nintegral equation to the relativistic, model-independent three-particle\nscattering amplitude. We motivate the appearance of the intermediate quantity,\nexplain how it is related to the standard amplitude, and discuss prospects for\nusing the result to constrain three-particle observables."
    },
    {
        "anchor": "Probing the interior of the Colour Flux Tube: In the dual superconductivity description of quark confinement the core of\nthe flux tube connecting a quark pair belongs to a deconfined, hot phase. This\ncan be checked in numerical experiments on 3D $Z_2$ gauge model. It is also\npointed out that the Svetitsky-Yaffe conjecture provides analytic expressions\nfor the distribution of the flux density around quark sources at critical\ntemperature.",
        "positive": "Heavy-light Mesons and Baryons with b quarks: We present lattice results for the spectrum of mesons containing one heavy\nquark and of baryons containing one or two heavy quarks. The calculation is\ndone in the quenched approximation using the NRQCD formalism for the heavy\nquark. We analyze the dependence of the mass splittings on both the heavy and\nthe light quark masses. Meson P-state fine structure and baryon hyperfine\nsplittings are resolved for the first time. We fix the b quark mass using both\nM_B and M_{\\Lambda_b}, and our best estimate is m_b^\\MSbar(m_b^\\MSbar) =\n4.35(10)({}^{-3}_{+2})(10) GeV. The spectrum, obtained by interpolation to m_b,\nis compared with the experimental data."
    },
    {
        "anchor": "The Maximal Abelian Gauge in SU(3) Lattice Gauge Theory: We gauge fix 600 SU(3) beta=6.0 configurations on a 16^4 lattice to a simple\nform of the maximal abelian gauge. We project the SU(3) valued links to the\nU(1)xU(1) subgroup, and extract U(1)xU(1) and monopole string tensions. After\ngauge fixing to the indirect center gauge, the U(1)xU(1) links are projected to\nZ(3) and a vortex string tension is measured. The vortex and magnetic current\ndensities are measured.",
        "positive": "Simulations of Dynamically Triangulated Gravity -- an Algorithm for\n  Arbitrary Dimension: Recent models for discrete euclidean quantum gravity incorporate a sum over\nsimplicial triangulations. We describe an algorithm for simulating such models\nin general dimensions. As illustration we show results from simulations in four\ndimensions"
    },
    {
        "anchor": "A New Gauge Fixing Method for Abelian Projection: We formulate a stochastic gauge fixing method to study the gauge dependence\nof the Abelian projection. We consider a gauge which interpolates between the\nmaximal Abelian gauge and no gauge fixing. We have found that Abelian dominance\nfor the heavy quark potential holds even in a gauge which is far from maximally\nAbelian one. The heavy quark potentials from monopole and photon contribution\nare calculated at several values of the gauge parameter, and the former part\nshows always the confinement behavior.",
        "positive": "Perturbative calculation of the clover term for Wilson fermions in any\n  representation of the gauge group SU(N): We calculate the Sheikholeslami-Wohlert coefficient of the O(a) improvement\nterm for Wilson fermions in any representation of the gauge group SU(N)\nperturbatively at the one-loop level. The result applies to QCD with adjoint\nquarks and to N=1 supersymmetric Yang-Mills theory on the lattice."
    },
    {
        "anchor": "Light hadron spectrum and quark masses: Recent developments in lattice QCD calculations of the light hadron spectrum\nand quark masses are reviewed.",
        "positive": "Subsets and the canonical partition functions: We explain the physical nature of the subset solution to the sign problem in\nchiral random matrix theory: The subset sum is shown to project out the\ncanonical determinant with zero quark charge from a given configuration. As the\ngrand canonical chiral random matrix partition function is independent of the\nchemical potential, the zero quark charge sector provides the full result."
    },
    {
        "anchor": "Moments of Parton Distributions Functions from Lattice QCD at the\n  Physical Point: We present a Lattice QCD calculation of the second Mellin moments of the\nnucleon axial, vector and tensor parton distribution functions (PDFs). The\ncalculation is performed at the physical pion mass with two different lattice\nspacings, and includes both zero and non-zero nucleon momenta. In our\npreliminary analysis, we identify operators that greatly reduce excited-state\ncontamination.",
        "positive": "Identification of shallow two-body bound states in finite volume: We discuss signatures of bound-state formation in finite volume via the\nLuscher finite size method. Assuming that the phase-shift formula in this\nmethod inherits all aspects of the quantum scattering theory, we may expect\nthat the bound-state formation induces the sign of the scattering length to be\nchanged. If it were true, this fact provides us a distinctive identification of\na shallow bound state even in finite volume through determination of whether\nthe second lowest energy state appears just above the threshold. We also\nconsider the bound-state pole condition in finite volume, based on Luscher's\nphase-shift formula and then find that the condition is fulfilled only in the\ninfinite volume limit, but its modification by finite size corrections is\nexponentially suppressed by the spatial lattice size L. These theoretical\nconsiderations are also numerically checked through lattice simulations to\ncalculate the positronium spectrum in compact scalar QED, where the short-range\ninteraction between an electron and a positron is realized in the Higgs phase."
    },
    {
        "anchor": "Extracting $F_\u03c0$ from small lattices: unquenched results: We calculate the response of the microscopic Dirac spectrum to an imaginary\nisospin chemical potential for QCD with two dynamical flavors in the chiral\nlimit. This extends our previous calculation from the quenched to the\nunquenched theory. The resulting spectral correlation function in the\n$\\epsilon$-regime provides here, too, a new and efficient way to measure\n$F_\\pi$ on the lattice. We test the method in a hybrid Monte Carlo simulation\nof the theory with two staggered quarks.",
        "positive": "Phase structure analysis of CP(N-1) model using Tensor renormalization\n  group: The phase structure of the lattice CP($N-1$) model in two dimensions is\nanalyzed by the tensor renormalization group (TRG) method. We focus on the case\n$N=2$ and compare the numerical result of the TRG method with that of the\nstrong-coupling analysis in the presence of the $\\theta$ term and investigate\nthe nature of the phase transition at $\\theta=\\pi$."
    },
    {
        "anchor": "Novel $|V_{us}|$ Determination Using Inclusive Strange $\u03c4$ Decay and\n  Lattice HVPs: We propose and apply a new approach to determining $|V_{us}|$ using\ndispersion relations with weight functions having poles at Euclidean\n(space-like) momentum which relate strange hadronic $\\tau$ decay distributions\nto hadronic vacuum polarization functions (HVPs) obtained from lattice QCD. We\nshow examples where spectral integral contributions from the region where\nexperimental data have large errors or do not exist are strongly suppressed but\naccurate determinations of the relevant lattice HVP combinations remain\npossible. The resulting $|V_{us}|$ agrees well with determinations from $K$\nphysics and 3-family CKM unitarity. Advantages of this new approach over the\nconventional hadronic $\\tau$ decay determination employing flavor-breaking sum\nrules are also discussed.",
        "positive": "Systematics of Staggered Fermion Spectral Properties and Topology: The spectral properties of a variety of improved staggered operators are\nstudied in quenched QCD. The systematic dependence of the infrared eigenvalue\nspectrum on i) improvement in the staggered operator, ii) improvement in the\ngauge field action, iii) lattice spacing and iv) lattice volume, is analyzed.\nIt is observed that eigenmodes with small eigenvalues and large chirality\nappear as the level of improvement increases or as one approaches the continuum\nlimit. These eigenmodes can be identified as the ``zero modes'' which\ncontribute to the chirality associated, via the index theorem, with the\ntopology of the background gauge field. This gives evidence that staggered\nfermions are sensitive to gauge field topology. After successfully identifying\nthese would-be chiral zero modes, the distribution of the remaining non-chiral\nmodes is compared with the predictions of Random Matrix Theory in different\ntopological sectors. Satisfactory agreement is obtained."
    },
    {
        "anchor": "The SU(3) Beta Function from Numerical Stochastic Perturbation Theory: The SU(3) beta function is computed from Wilson loops to 20th order numerical\nstochastic perturbation theory. An attempt is made to include massless\nfermions, whose contribution is known analytically to 4th order. The question\nwhether the theory admits an infrared stable fixed point is addressed.",
        "positive": "Benchmarking quantum computers for real-time evolution of a $(1+1)$\n  field theory with error mitigation: Quantum computers open the possibility of performing real-time calculations\nfor quantum field theory scattering processes. We propose to use an index\naveraging the absolute value of the difference between the accurately\ncalculated Trotter evolution of site occupations and their actual measurements\non NISQ machines. The average is over all the qubits for a certain number of\nTrotter steps. We use this metric to quantify the progress made in successive\nstate-of-the-art machines and error-mitigation techniques. We illustrate the\nconcept with the transverse Ising model in one spatial dimension with four\nsites using three of IBM's quantum computers (Almaden, Boeblingen, and\nMelbourne). We discuss the size of the Trotter steps needed to achieve physics\ngoals. Using the proposed metric, we show that readout mitigation methods and\nRichardson extrapolations of mitigated measurements are very effective for\nspecific numbers of Trotter steps of a chosen size. This specific choice can be\napplied to other machines and noise mitigation methods. On the other hand, a\nreliable algorithmic mitigation would require a significantly larger number of\nsmaller Trotter steps."
    },
    {
        "anchor": "Lattice calculation of coordinate-space vector and axial-vector current\n  correlators in QCD: We study the vector and axial-vector current correlators in perturbative and\nnon-perturbative regimes of QCD. The correlators in Euclidean coordinate space\nare calculated on the lattice using the M\\\"obius domain-wall fermion\nformulation at three lattice spacings covering 0.044--0.080~fm. The dynamical\nquark effects of $2+1$ light flavors are included. The sum $V+A$ and the\ndifference $V-A$ of the vector ($V$) and axial-vector ($A$) current correlators\ncalculated on the lattice after extrapolating to the physical point agree with\nthose converted from the ALEPH experimental data of hadronic $\\tau$ decays. The\nlevel of the agreement in the $V+A$ channel is about $1.3\\sigma$ or smaller in\nthe region of $|x|\\ge0.4$~fm, while that in the $V-A$ channel is about\n$1.8\\sigma$ at $|x|=0.74$~fm and smaller at other distances. We also extract\nthe hiral condensate from the short-distance correlators on the lattice using\nthe PCAC relation. Its result extrapolated to the chiral and continuum limit is\ncompatible with other estimates at low energies.",
        "positive": "Finite-Size analysis of the 4-d abelian surface gauge model: We present the results of a finite-size analysis of the four dimensional\nabelian surface gauge model. This model is defined assigning abelian variables\nto the plaquettes of an hypercubical lattice, and is dual to the four\ndimensional Ising model. This last model is known to present a second order\nphase transition with mean field critical exponents. We have performed Monte\nCarlo simulations on several lattice sizes and high statistics. The analysis of\nthe partition function zeroes and the specific heat scaling behaviour allowed\nus to estimate the critical coupling $\\beta_c$ as well as the critical\nexponents $\\nu$ and $\\alpha$. Our results are consistent with the second order\ncritical exponents $\\nu = 1/2$ and $\\alpha = 0$. The $\\beta_c$ value is in\nperfect agreement with duality predictions from the 4-d Ising model.\nNevertheless, the energy histograms show a seemingly non-vanishing double peak\nstructure. The interface tension analysis suggests that this may be a finite\nsize effect."
    },
    {
        "anchor": "Step Scaling with Off Shell Renormalization: A method for computing renormalization constants in the Rome Southampton\nscheme with volume sources and arbitrary momenta is described. This new method\nis found to enable controlled and precise continuum extrapolations and opens\nthe way to compute the running of operators nonperturbatively in the Rome\nSouthampton scheme. We describe this in detail and exhibit several examples of\nlattice step scaling functions.",
        "positive": "Two-loop computation of a finite volume running coupling on the lattice: In pure SU(2) gauge theory we compute the two-loop coefficient in the\nrelation between the lattice bare coupling and the running coupling defined\nthrough the Schroedinger functional. This result is required to relate the\nlatter to the MSbar-coupling in our programme to compute alpha_s. In addition\nit allows us to implement O(a) improvement of the Schroedinger functional to\ntwo-loop order. The two-loop beta-function is verified in a perturbative\ncomputation on the lattice, and the behavior of expansions in the standard and\nin the Parisi-improved bare couplings are investigated beyond one loop."
    },
    {
        "anchor": "Revisiting strong coupling QCD at finite temperature and baryon density: The strong coupling limit ($\\beta_{gauge}=0$) of lattice QCD with staggered\nfermions enjoys the same non-perturbative properties as continuum QCD, namely\nconfinement and chiral symmetry breaking. In contrast to the situation at weak\ncoupling, the sign problem which appears at finite density can be brought under\ncontrol for a determination of the full (mu,T) phase diagram by Monte Carlo\nsimulations. Further difficulties with efficiency and ergodicity of the\nsimulations, especially at the strongly first-order, low-T, finite-mu\ntransition, are addressed respectively with a worm algorithm and multicanonical\nsampling. Our simulations reveal sizeable corrections to the old results of\nKarsch and Muetter. Comparison with analytic mean-field determinations of the\nphase diagram shows discrepancies of O(10) in the location of the QCD critical\npoint.",
        "positive": "Understanding chiral symmetry breaking with the overlap action: A chiral fermion action allows one to do very clean studies of chiral\nsymmetry breaking in QCD. I will briefly describe how to compute with the\noverlap action (relatively) cheaply, and then turn to physics: Low modes of the\nDirac operator show a ``lumped'' chiral density which peaks at the locations of\ninstantons and anti-instantons. These modes dominate correlation functions at\nsmall quark mass in many channels. The picture qualitatively (and in some cases\nquantitatively) resembles an instanton liquid model."
    },
    {
        "anchor": "Anderson Localization in high temperature QCD: background configuration\n  properties and Dirac eigenmodes: We investigate the properties of the background gauge field configurations\nthat act as disorder for the Anderson localization mechanism in the Dirac\nspectrum of QCD at high temperatures. We compute the eigenmodes of the M\\\"obius\ndomain-wall fermion operator on configurations generated for the $SU(3)$ gauge\ntheory with two flavors of fermions, in the temperature range $[0.9,1.9]T_c$.\nWe identify the source of localization of the eigenmodes with gauge\nconfigurations that are self-dual and support negative fluctuations of the\nPolyakov loop $P_L$, in the high temperature sea of $P_L\\sim 1$. The dependence\nof these observations on the boundary conditions of the valence operator is\nstudied. We also investigate the spatial overlap of the left-handed and\nright-handed projected eigenmodes in correlation with the localization and the\ncorresponding eigenvalue. We discuss an interpretation of the results in terms\nof monopole-instanton structures.",
        "positive": "Lattice study of supersymmetry breaking in N=2 supersymmetric quantum\n  mechanics: We study supersymmetry breaking from a lattice model of N=2 supersymmetric\nquantum mechanics using the direct computational method proposed in\narXiv:1803.07960. The vanishing Witten index is realized as a numerical result\nin high precision. The expectation value of Hamiltonian is evaluated for the\ndouble-well potential. Compared with the previous Monte-Carlo results, the\nobtained vacuum energy coincides with the known values within small errors for\nstrong couplings. The instanton effect is also reproduced for weak couplings.\nThe used computational method helps us to evaluate the effect of finite lattice\nspacings more precisely and to study the mechanism of non-perturbative\nsupersymmetry breaking from lattice computations."
    },
    {
        "anchor": "Lorentz gauge fixing and lattice QED: The Gribov ambiguity problem is studied for compact lattice QED within the\nLorentz gauge. In the Coulomb phase, Gribov copies are mainly caused by double\nDirac sheets and zero-momentum modes of the gauge fields. Removing them by\n(non-) periodic gauge transformations allows to reach the absolute extremum of\nthe Lorentz gauge functional. For standard Lorentz gauge fixing the Wilson\nfermion correlator turns out to be strongly effected by the zero-momentum\nmodes. A reliable fermion mass estimate requires the proper treatment of these\nmodes.",
        "positive": "Gluon Propagator in the Infrared Region: The gluon propagator is calculated in quenched QCD for two different lattice\nsizes (16^3x48 and 32^3x64) at beta=6.0. The volume dependence of the\npropagator in Landau gauge is studied. The smaller lattice is instrumental in\nrevealing finite volume and anisotropic lattice artefacts. Methods for\nminimising these artefacts are developed and applied to the larger lattice\ndata. New structure seen in the infrared region survives these conservative\ncuts to the lattice data. This structure serves to rule out a number of models\nthat have appeared in the literature. A fit to a simple analytical form\ncapturing the momentum dependence of the nonperturbative gluon propagator is\nalso reported."
    },
    {
        "anchor": "Partial Wave Mixing in Hamiltonian Effective Field Theory: We explore partial-wave mixing in the finite volume based on HEFT, and\nprovide the P-Matrix to show the degree of partial-wave mixing. An example of\nisospin-2 $\\pi\\pi$ scattering is used to check the consistency between HEFT and\nL\\\"{u}scher's method.",
        "positive": "Lattice Formulation for 2d N=(2,2), (4,4) Super Yang-Mills Theories\n  without Admissibility Conditions: We present a lattice formulation for two-dimensional N=(2,2) and (4,4)\nsupersymmetric Yang-Mills theories that resolves vacuum degeneracy for gauge\nfields without imposing admissibility conditions. Cases of U(N) and SU(N) gauge\ngroups are considered, gauge fields are expressed by unitary link variables,\nand one or two supercharges are preserved on the two-dimensional square\nlattice. There does not appear fermion doubler, and no fine-tuning is required\nto obtain the desired continuum theories in a perturbative argument. This\nformulation is expected to serve as a more convenient basis for numerical\nsimulations. The same approach will also be useful to other two-dimensional\nsupersymmetric lattice gauge theories with unitary link variables constructed\nso far -- for example, N=(8,8) supersymmetric Yang-Mills theory and N=(2,2)\nsupersymmetric QCD."
    },
    {
        "anchor": "Chiral Lattice Gauge Theories Via Mirror-Fermion Decoupling: A Mission\n  (im)Possible?: This is a review of the status and outstanding issues in attempts to\nconstruct chiral lattice gauge theories by decoupling the mirror fermions from\na vectorlike theory. In the first half, we explain why studying nonperturbative\nchiral gauge dynamics may be of interest, enumerate the problems that a lattice\nformulation of chiral gauge theories must overcome, and briefly review our\ncurrent knowledge. We then discuss the motivation and idea of mirror-fermion\ndecoupling and illustrate the desired features of the decoupling dynamics by a\nsimple solvable toy model. The role of exact chiral symmetries and matching of\n't Hooft anomalies on the lattice is also explained. The second, more\ntechnical, half of the article is devoted to a discussion of the known and\nunknown features of mirror-decoupling dynamics formulated with Ginsparg-Wilson\nfermions. We end by pointing out possible directions for future studies.",
        "positive": "Isospin Breaking Corrections to the HVP with Domain Wall Fermions: We present results for the QED and strong isospin breaking corrections to the\nhadronic vacuum polarization using $N_f=2+1$ Domain Wall fermions. QED is\nincluded in an electro-quenched setup using two different methods, a stochastic\nand a perturbative approach. Results and statistical errors from both methods\nare directly compared with each other."
    },
    {
        "anchor": "Numerical confirmation of analytic predictions for the finite volume\n  mass gap of the XY-model: Recent exact predictions for the massive scaling limit of the two dimensional\nXY-model are based on the equivalence with the sine-Gordon theory and include\ndetailed results on the finite size behavior. The so-called step-scaling\nfunction of the mass gap is simulated with very high precision and found\nconsistent with analytic results in the continuum limit. To come to this\nconclusion, an also predicted form of a logarithmic decay of lattice artifacts\nwas essential to use for the extrapolation.",
        "positive": "A construction of the Schr\u00f6dinger Functional for M\u00f6bius Domain Wall\n  Fermions: We construct the Schr\\\"odinger Functional (SF) setup for the M\\\"obius domain\nwall fermions (MDWF). The method is an extension of the method proposed by\nTakeda for the standard domain wall fermion. In order to fulfill the\nrequirement that the lattice Dirac operator with the SF boundary obeys the\nL\\\"uscher's universality argument: the lattice chiral fermion with the SF\nboundary condition breaks the chiral symmetry at the temporal boundary, we\nimpose the parity symmetry with respect to the fifth-direction on the MDWF\noperator. This additional symmetry restricts the choice of the parameter of the\nMDWF so that the optimal parameter from the Zolotarev optimal approximation\ncannot be applied. We introduce a modified parameter set having the\nfifth-dimensional parity symmetry. We investigate the MDWF with the SF boundary\nby observing eigenvalues of the Hermitian operator and the Ginsparg-Wilson\nrelation violation at the tree-level. We compare the computational cost with\nthat of the standard DWF with the SF scheme."
    },
    {
        "anchor": "Two Meson Systems with Ginsparg-Wilson Valence Quarks: Unphysical effects associated with finite lattice spacing and partial\nquenching may lead to the presence of unphysical terms in chiral extrapolation\nformulae. These unphysical terms must then be removed during data analysis\nbefore physical predictions can be made. In this work, we show that through\nnext-to-leading order, there are no unphysical counterterms in the\nextrapolation formulae, expressed in lattice-physical parameters, for meson\nscattering lengths in theories with Ginsparg-Wilson valence quarks. Our work\napplies to most sea quark discretization, provided that chiral perturbation\ntheory is a valid approximation. We demonstrate our results with explicit\ncomputations and show that, in favorable circumstances, the extrapolation\nformulae do not depend on the unknown constant C_Mix appearing at lowest order\nin the mixed action chiral Lagrangian. We show that the I=1 KK scattering\nlength does not depend on C_Mix in contrast to the I=3/2 K-pi scattering\nlength. In addition, we show that these observables combined with f_K / f_pi\nand the I=2 pi-pi scattering length share only two linearly independent sets of\ncounterterms, providing a means to test the mixed action theory at one lattice\nspacing. We therefore make a prediction for the I=1 KK scattering length.",
        "positive": "Study of the complex fermion determinant in a $\\rm U(1)_L \\otimes\n  U(1)_R$ symmetric Yukawa model: Lattice theories that contain chiral multiplets of fermions can have complex\nfermion determinants. This is for example the case for the $\\rm U(1)_L \\otimes\nU(1)_R$ symmetric Yukawa model with mirror fermions, if the number of\ngenerations of fermions and mirror fermions is odd. Whether a numerical\nsimulation of such a model is possible depends on the magnitude of fluctuations\nof the complex phase factor of the fermion determinant. We investigate the\nfermion determinant of the U(1) Yukawa model with mirror fermions for a\nphysically relevant choice of parameters. The argument of the complex phase\nturns out to fluctuate only very little and is at most of the order of $2 \\cdot\n10^{-3}$."
    },
    {
        "anchor": "Charmed bottom baryon spectroscopy from lattice QCD: We calculate the masses of baryons containing one, two, or three heavy quarks\nusing lattice QCD. We consider all possible combinations of charm and bottom\nquarks, and compute a total of 36 different states with $J^P = \\frac12^+$ and\n$J^P = \\frac32^+$. We use domain-wall fermions for the up, down, and strange\nquarks, a relativistic heavy-quark action for the charm quarks, and\nnonrelativistic QCD for the bottom quarks. Our analysis includes results from\ntwo different lattice spacings and seven different pion masses. We perform\nextrapolations of the baryon masses to the continuum limit and to the physical\npion mass using $SU(4|2)$ heavy-hadron chiral perturbation theory including\n$1/m_Q$ and finite-volume effects. For the 14 singly heavy baryons that have\nalready been observed, our results agree with the experimental values within\nthe uncertainties. We compare our predictions for the hitherto unobserved\nstates with other lattice calculations and quark-model studies.",
        "positive": "An investigation into a wavelet accelerated gauge fixing algorithm: We introduce an acceleration algorithm for coulomb gauge fixing, using the\ncompactly supported wavelets introduced by Daubechies. The algorithm is similar\nto Fourier acceleration. Our provisional numerical results for $SU(3)$ on\n$8^{4}$ lattices show that the acceleration based on the DAUB6 transform can\nreduce the number of iterations by a factor up to 3 over the unaccelerated\nalgorithm. The reduction in iterations for Fourier acceleration is\napproximately a factor of 7."
    },
    {
        "anchor": "Casimir Scaling of domain wall tensions in the deconfined phase of D=3+1\n  SU(N) gauge theories: We perform lattice calculations of the spatial 't Hooft k-string tensions in\nthe deconfined phase of SU(N) gauge theories for N=2,3,4,6. These equal (up to\na factor of T) the surface tensions of the domain walls between the\ncorresponding (Euclidean) deconfined phases. For T much larger than T_c our\nresults match on to the known perturbative result, which exhibits Casimir\nScaling, being proportional to k(N-k). At lower T the coupling becomes stronger\nand, not surprisingly, our calculations show large deviations from the\nperturbative T-dependence. Despite this we find that the behaviour proportional\nto k(N-k) persists very accurately down to temperatures very close to T_c. Thus\nthe Casimir Scaling of the 't Hooft tension appears to be a `universal' feature\nthat is more general than its origin in the low order high-T perturbative\ncalculation. We observe the `wetting' of these k-walls at T around T_c and the\n(almost inevitable) `perfect wetting' of the k=N/2 domain wall. Our\ncalculations show that as T tends to T_c the magnitude of the spatial `t Hooft\nstring tension decreases rapidly.",
        "positive": "Fast Partitioning of Pauli Strings into Commuting Families for\n  Expectation Value Measurements of Dense Operators: The cost of measuring quantum expectation values of an operator can be\nreduced by grouping the Pauli string ($SU(2)$ tensor product) decomposition of\nthe operator into maximally commuting sets. We detail an algorithm, presented\nin [1], to partition the full set of $m$-qubit Pauli strings into the minimal\nnumber of commuting families, and benchmark the performance with dense\nHamiltonians on IBM hardware. Here we also compare how our method scales\ncompared to graph-theoretic techniques for the generally commuting case."
    },
    {
        "anchor": "Inverse Laplace transform on the lattice spacing: Inverse Laplace transform on the lattice spacing is introduced as a\ncomputational framework of the extrapolation of the strong coupling expansion\nto the scaling region. We apply the transform to the two-dimensional non-linear\nO(N) model at N>=3 and show that the approximation of the continuum limit of\nthe susceptibility agrees with the existing theoretical and Monte Carlo data.",
        "positive": "Dynamical fermions, centre vortices, and emergent phenomena: The non-trivial ground-state vacuum fields of QCD form the foundation of\nmatter. Here we examine the centre vortices identified within the ground-state\nfields of lattice QCD. We aim to understand the manner in which dynamical\nfermions in the QCD vacuum alter the centre-vortex structure. Using modern\nvisualisation techniques, the centre-vortex structure of pure-gauge and\ndynamical-fermion fields is quantified and compared. We then explore the impact\nthis modified structure has on measures of confinement and dynamical mass\ngeneration. The string tension of the static quark potential,\npositivity-violation in the gluon propagator, and dynamical mass generation in\nthe overlap quark propagator are of particular interest. The impact of\ndynamical fermions is significant and provides new insights into the role of\ncentre vortices in underpinning both confinement and dynamical chiral symmetry\nbreaking in QCD."
    },
    {
        "anchor": "Properties and uses of the Wilson flow in lattice QCD: Theoretical and numerical studies of the Wilson flow in lattice QCD suggest\nthat the gauge field obtained at flow time t>0 is a smooth renormalized field.\nThe expectation values of local gauge-invariant expressions in this field are\nthus well-defined physical quantities that probe the theory at length scales on\nthe order of sqrt(t). Moreover, by transforming the QCD functional integral to\nan integral over the gauge field at a specified flow time, the emergence of the\ntopological (instanton) sectors in the continuum limit becomes transparent and\nis seen to be caused by a dynamical effect that rapidly separates the sectors\nwhen the lattice spacing is reduced from 0.1 fm to smaller values.",
        "positive": "Higher representations on the lattice: perturbative studies: We present analytical results to guide numerical simulations with Wilson\nfermions in higher representations of the colour group. The ratio of $\\Lambda$\nparameters, the additive renormalization of the fermion mass, and the\nrenormalization of fermion bilinears are computed in perturbation theory,\nincluding cactus resummation. We recall the chiral Lagrangian for the different\npatterns of symmetry breaking that can take place with fermions in higher\nrepresentations, and discuss the possibility of an Aoki phase as the fermion\nmass is reduced at finite lattice spacing."
    },
    {
        "anchor": "Can stochastic quantization evade the sign problem? -- the relativistic\n  Bose gas at finite chemical potential: A nonperturbative study of field theories with a complex action, such as QCD\nat finite baryon density, is difficult due to the sign problem. We show that\nthe relativistic Bose gas at finite chemical potential has a sign and `Silver\nBlaze' problem, similar to QCD. We then apply stochastic quantization and\ncomplex Langevin dynamics to study this theory with nonperturbative lattice\nsimulations. Independence of chemical potential at small and a transition to a\ncondensed phase at large chemical potential are found. Lattices of size N^4,\nwith N=4,6,8,10, are used. We show that the sign problem is severe, however, we\nfind that it has no negative effect using this approach. This improves the\nprospects of applying stochastic quantization to QCD at nonzero density.",
        "positive": "$\\mathcal PT$ symmetry, pattern formation, and finite-density QCD: A longstanding issue in the study of quantum chromodynamics (QCD) is its\nbehavior at nonzero baryon density, which has implications for many areas of\nphysics. The path integral has a complex integrand when the quark chemical\npotential is nonzero and therefore has a sign problem, but it also has a\ngeneralized $\\mathcal PT$ symmetry. We review some new approaches to $\\mathcal\nPT$-symmetric field theories, including both analytical techniques and methods\nfor lattice simulation. We show that $\\mathcal PT$-symmetric field theories\nwith more than one field generally have a much richer phase structure than\ntheir Hermitian counterparts, including stable phases with patterning behavior.\nThe case of a $\\mathcal PT$-symmetric extension of a $\\phi^4$ model is\nexplained in detail. The relevance of these results to finite density QCD is\nexplained, and we show that a simple model of finite density QCD exhibits a\npatterned phase in its critical region."
    },
    {
        "anchor": "Open charm mesons at nonzero temperature: results in the hadronic phase\n  from lattice QCD: We study what happens to D and D_s mesons as the temperature increases, using\nlattice QCD simulations with N_f=2+1 dynamical flavours on anistropic lattices.\nWe have access to five temperatures in the hadronic phase. Using the determined\ngroundstate mass at the lowest temperature, we investigate the effect of rising\ntemperature by analysing ratios of mesonic correlators, without the need for\nfurther fitting or spectral reconstruction. In the pseudoscalar and vector\nchannels, we demonstrate that temperature effects are at the percent level and\ncan be captured by a reduction of the groundstate mass as the thermal crossover\nis approached. In the axial-vector and scalar channels on the other hand,\ntemperature effects are prominent throughout the hadronic phase.",
        "positive": "Exact Chiral Symmetry for Domain Wall Fermions with Finite L_s: We show how the standard domain wall action can be simply modified to allow\narbitrarily exact chiral symmetry at finite fifth dimensional extent $L_s$. We\nnote that the method can be used for both quenched and dynamical calculations.\nWe test the method using smooth and thermalized gauge field configurations. We\nalso make comparisons of the performance (cost) of the domain wall operator for\nspectroscopy compared to other methods such as the overlap-Dirac operator and\nfind both methods are comparable in cost."
    },
    {
        "anchor": "The structure of the gluon propagator: The gluon propagator has been calculated for quenched QCD in the Landau gauge\nat beta=6.0 for volumes 16^3x48 and 32^3x64, and at beta=6.2 for volume\n24^3x48$. The large volume and different lattice spacings allow us to identify\nand minimise finite volume and finite lattice spacing artefacts. We also study\nthe tensor structure of the gluon propagator, confirming that it obeys the\nlattice Landau gauge condition.",
        "positive": "Nucleon Magnetic Moments, their Quark Mass Dependence and Lattice QCD\n  Extrapolations: We calculate the quark mass dependence of both isovector and isoscalar\nanomalous magnetic moments of the nucleon in a chiral effective field theory\nwith explicit pion, nucleon and Delta(1232) degrees of freedom to\nleading-one-loop order. In the isovector sector we fit 3 unknown couplings of\nthe effective Lagrangian to available lattice data and obtain a surprisingly\nwell-behaved extrapolation function connecting the chiral limit, experimental\ndata and the lattice simulations. We also discuss the polynomial quark mass\ndependence in the isoscalar sector and finally compare with the Pade formula of\nthe Adelaide group."
    },
    {
        "anchor": "Lattice QCD estimate of the quark-gluon plasma photon emission rate: We present a computation of the photon emission rate of the quark-gluon\nplasma from two-flavor lattice QCD at a temperature of 254 MeV, which follows\nup on the work presented in [1]. We perform a continuum extrapolation of the\nvector-current correlator, and consider a linear combination of the Lorentz\nindices corresponding to a UV-finite spectral function. To extract the spectral\nfunction from the lattice correlators, an ill-posed inverse problem, we model\nthe spectral function with a Pad\\'e ansatz. We further constrain our analysis\nby simultaneously fitting data with different momenta. We present results for a\nmulti-momentum fit including the three smallest momenta available from our\nlattice analysis.",
        "positive": "Investigation of the hadronic light-by-light contribution to the muon\n  $g{-}2$ using staggered fermions: Hadronic contributions dominate the uncertainty of the standard model\nprediction for the anomalous magnetic moment of the muon. In this work, we\ndescribe an ongoing lattice calculation of the hadronic light-by-light\ncontribution, performed with staggered fermions. The presence of quarks with\ndifferent tastes complicates the analysis of the position-space correlation\nfunction. We present a suitable adaption of the \"Mainz method\". As a first\nnumerical test, we reproduce the well-known lepton-loop contribution. Results\nat a single lattice spacing for the light quark contribution, using two\nvolumes, are then discussed. Our study of the long distance behavior and\nfinite-volume effects is supplemented by considering the contribution of the\nlight pseudoscalar-pole. The corresponding transition form factors have been\nevaluated in previous simulations on the same ensembles."
    },
    {
        "anchor": "Lattice Calculation of QCD Vacuum Correlation Functions: The first exploratory calculations of QCD vacuum correlation functions on a\nlattice are reported. Qualitative agreement with phenomenological results is\nobtained in channels for which experimental data are available, and these\ncorrelation functions are shown to be useful in exploring approximations based\non sum rules and interacting instantons.",
        "positive": "Perturbative renormalization of staggered fermion operators with stout\n  improvement: Application to the magnetic susceptibility of QCD: We calculate the fermion propagator and the quark-antiquark Green's functions\nfor a complete set of ultralocal fermion bilinears, ${{\\cal O}_\\Gamma}$\n[$\\Gamma$: scalar (S), pseudoscalar (P), vector (V), axial (A) and tensor (T)],\nusing perturbation theory up to one-loop and to lowest order in the lattice\nspacing. We employ the staggered action for fermions and the Symanzik Improved\naction for gluons. From our calculations we determine the renormalization\nfunctions for the quark field and for all ultralocal taste-singlet bilinear\noperators. The novel aspect of our calculations is that the gluon links which\nappear both in the fermion action and in the definition of the bilinears have\nbeen improved by applying a stout smearing procedure up to two times,\niteratively. Compared to most other improved formulations of staggered\nfermions, the above action, as well as the HISQ action, lead to smaller taste\nviolating effects. The renormalization functions are presented in the RI$'$\nscheme; the dependence on all stout parameters, as well as on the coupling\nconstant, the number of colors, the lattice spacing, the gauge fixing parameter\nand the renormalization scale, is shown explicitly.\n  We apply our results to a nonperturbative study of the magnetic\nsusceptibility of QCD at zero and finite temperature. In particular, we\nevaluate the \"tensor coefficient\", $\\tau$, which is relevant to the anomalous\nmagnetic moment of the muon."
    },
    {
        "anchor": "High Precision Verification of the Kosterlitz Thouless Scenario: We verify the Kosterlitz Thouless scenario for three different SOS\n(solid-on-solid) models, including the dual transforms of XY-models with\nVillain and with cosine action. The method is based on a matching of the\nrenormalization group (RG) flow of the candidate models with the flow of a bona\nfide KT model, the exactly solvable BCSOS model. We obtain high precision\nestimates for the critical couplings and other non-universal quantities.",
        "positive": "$I=1$ $\u03c0$-$\u03c0$ scattering at the physical point: We present a preliminary analysis of $I=1$ $\\pi\\,\\pi$ scattering at the\nphysical point. We make use of the stochastic variant of the distillation\nframework (also known as sLapH) to compute the relevant two-point correlation\nmatrices using a basis of single and multihadron interpolating operators to\nestimate the low energy spectra. We perform the L\\\"uscher analysis to determine\nthe scattering phase shift which is finding good agreement with the\nexperimentally obtained phase shifts."
    },
    {
        "anchor": "Phase transition and topology in 4d simplicial gravity: We present data indicating that the recent evidence for the phase transition\nbeing of first order does not result from a breakdown of the ergodicity of the\nalgorithm. We also present data showing that the thermodynamical limit of the\nmodel is independent of topology.",
        "positive": "Light-by-light forward scattering amplitudes in Lattice QCD: We present our preliminary results on the calculation of hadronic\nlight-by-light forward scattering amplitudes using vector four-point\ncorrelation functions computed on the lattice. Using a dispersive approach,\nforward scattering amplitudes can be described by $\\gamma^* \\gamma^* \\to$\nhadrons fusion cross sections and then compared with phenomenology. We show\nthat only a few states are needed to reproduce our data. In particular, the sum\nrules considered in this study imply relations between meson$-\\gamma\\gamma$\ncouplings and provide valuable information about individual form factors which\nare often used to estimate the meson-pole contributions to the hadronic\nlight-by-light contribution to the $(g-2)$ of the muon."
    },
    {
        "anchor": "Asymptotic scaling corrections in QCD with Wilson fermions from the\n  3-loop average plaquette: We calculate the 3-loop perturbative expansion of the average plaquette in\nlattice QCD with N_f massive Wilson fermions and gauge group SU(N). The\ncorrections to asymptotic scaling in the corresponding energy scheme are also\nevaluated. We have also improved the accuracy of the already known pure gluonic\nresults at 2 and 3 loops.",
        "positive": "A meron cluster solution for the sign problem of the two-dimensional\n  O(3) model: The two-dimensional O(3) model at a vacuum angle theta=pi is investigated.\nThis model has a severe sign problem. By a Wolff cluster algorithm an integer\nor half-integer topological charge is assigned to each cluster. The meron\nclusters (clusters with half-integer topological charge) are used to construct\nan improved estimator for the correlation function of two spins at theta=pi.\nOnly configurations with 0 and 2 merons contribute to this correlation\nfunction.\n  An algorithm, that generates configurations with only 0 and 2 merons, is\nconstructed and numerical simulations at theta=pi are performed.\n  The numerical results indicate the presence of long range correlations at\ntheta=pi."
    },
    {
        "anchor": "Staggered fermions and their $O(a)$ improvements: Expanding upon the arguments of Sharpe, we explicitly implement the Symanzik\nimprovement program demonstrating the absence of order $a$ terms in the\nstaggered fermion action. We propose a general program to improve fermion\noperators to remove $O(a)$ corrections from their matrix elements, and\ndemonstrate this program for the examples of matrix elements of fermion\nbilinears and $B_K$. We also determine the additional operators which must be\nadded to improve the staggered fermion currents.",
        "positive": "Ideal Walking Dynamics via a Gauged NJL Model: According to the Ideal Walking Technicolor paradigm large mass anomalous\ndimensions arise in gauged Nambu--Jona-Lasinio (NJL) models when the\nfour-fermion coupling is sufficiently strong to induce spontaneous symmetry\nbreaking in an otherwise conformal gauge theory. We therefore study the $SU(2)$\ngauged NJL model with two adjoint fermions using lattice simulations. The model\nis in an infrared conformal phase at small NJL coupling while it displays a\nchirally broken phase at large NJL couplings. In the infrared conformal phase\nwe find that the mass anomalous dimension varies with the NJL coupling reaching\n$\\gamma_m \\sim 1$ close to the chiral symmetry breaking transition, de facto\nmaking the present model the first explicit realization of the Ideal Walking\nscenario."
    },
    {
        "anchor": "Self-consistent Calculation of Real Space Renormalization Group Flows\n  and Effective Potentials: We show how to compute real space renormalization group flows in lattice\nfield theory by a self-consistent method. In each step, the integration over\nthe fluctuation field (high frequency components of the field) is performed by\na saddle point method. The saddle point depends on the block-spin. Higher\npowers of derivatives of the field are neglected in the actions, but no\npolynomial approximation in the field is made. The flow preserves a simple\nparameterization of the action. In this paper we treat scalar field theories as\nan example.",
        "positive": "Self-learning Monte-Carlo for non-abelian gauge theory with dynamical\n  fermions: In this paper, we develop the self-learning Monte-Carlo (SLMC) algorithm for\nnon-abelian gauge theory with dynamical fermions in four dimensions to resolve\nthe autocorrelation problem in lattice QCD. We perform simulations with the\ndynamical staggered fermions and plaquette gauge action by both in HMC and SLMC\nfor zero and finite temperature to examine the validity of SLMC. We confirm\nthat SLMC can reduce autocorrelation time in non-abelian gauge theory and\nreproduces results from HMC. For finite temperature runs, we confirm that SLMC\nreproduces correct results with HMC, including higher-order moments of the\nPolyakov loop and the chiral condensate. Besides, our finite temperature\ncalculations indicate that four flavor QC${}_2$D with $\\hat{m} = 0.5$ is likely\nin the crossover regime in the Colombia plot."
    },
    {
        "anchor": "Fourier coefficients of the net-baryon number density: We calculate Fourier coefficients of the net-baryon number as a function of a\npurely imaginary chemical potential. The asymptotic behavior of these\ncoefficients is governed by the singularity structure of the QCD partition\nfunction and thus encodes information on phase transitions. For the calculation\nof the Fourier coefficients from lattice data of the Bielefeld-Parma\ncollaboration we use a novel Filon-type quadrature, designed for highly\noscillatory integrals. We find sensitivity to chiral scaling in a narrow\ntemperature interval below the Roberge-Weiss transition temperature. Scaling\nfits yield reasonable values for the position of the Lee-Yang edge singularity\nin the complex chemical potential plane. Our lattice data has been obtained\nfrom simulations with (2+1)-flavors of highly improved staggered quarks (HISQ)\nat imaginary chemical potential on $N_\\tau=4, 6$ and $8$ lattices at physical\nquark masses.",
        "positive": "Simulating QCD at nonzero baryon density to all orders in the hopping\n  parameter expansion: Progress in simulating QCD at nonzero baryon density requires, amongst\nothers, substantial numerical effort. Here we propose two different expansions\nto all orders in the hopping parameter, preserving the full Yang-Mills action,\nwhich are much cheaper to simulate. We carry out simulations using complex\nLangevin dynamics, both in the hopping expansions and in the full theory, for\ntwo flavours of Wilson fermions, and agreement is seen at sufficiently high\norder in the expansion. These results provide support for the use of complex\nLangevin dynamics to study QCD at nonzero density, both in the full and the\nexpanded theory, and for the convergence of the latter."
    },
    {
        "anchor": "Nonperturbative renormalization of asymmetric staple-shaped operators in\n  twisted mass lattice QCD: Staple-shaped Wilson line operators are necessary for the study of transverse\nmomentum-dependent parton distribution functions (TMDPDFs) in lattice QCD and\nbeyond. In this work, we study the renormalization of such operators in the\ngeneral case of an asymmetric staple. We analyze the mixing pattern of these\noperators using their symmetry properties, where we find that the possible\nmixing is restricted within groups of four operators. We then present numerical\nresults using the regularization independent momentum subtraction (RI/MOM)\nscheme to study the importance of mixing using one operator in particular, the\n$\\gamma_0$ operator. Based on these results, we consider the short distance\nratio (SDR) scheme, which is desirable in the absence of mixing. Finally, we\ninvestigate a variant of the RI/MOM scheme, where the renormalization factors\nare computed at short distances.",
        "positive": "An Improved Estimator for the Correlation Function of 2D Nonlinear Sigma\n  Models: I present a new improved estimator for the correlation function of 2D\nnonlinear sigma models. Numerical tests for the 2D XY model and the 2D\nO(3)-invariant vector model were performed. For small physical volume, i.e. a\nlattice size small compared to the to the bulk correlation length, a reduction\nof the statistical error of the finite system correlation length by a factor of\nup to 30 compared to the cluster-improved estimator was observed. This\nimprovement allows for a very accurate determination of the running coupling\nproposed by M. L\"uscher et al. for 2D O(N)-invariant vector models."
    },
    {
        "anchor": "Anomalous finite-size scaling at thermal first-order transitions in\n  systems with disordered boundary conditions: We investigate the equilibrium and off-equilibrium behaviors of systems at\nthermal first-order transitions (FOTs) when the boundary conditions favor one\nof the two phases. As a theoretical laboratory we consider the two-dimensional\nPotts model. We show that an anomalous finite-size scaling emerges in systems\nwith open boundary conditions favoring the disordered phase, associated with a\nmixed regime where the two phases are spatially separated. Correspondingly, if\nthe system is slowly heated across the transition, the characteristic times of\nthe off-equilibrium dynamics scale with a power of the size. We argue that\nthese features generally apply to systems at FOTs, when boundary conditions\nfavor one of the two phases. In particular, they should be relevant for the\nexperimental search of FOTs of the quark-gluon plasma in heavy-ion collisions.",
        "positive": "On the critical line of 2+1 flavor QCD: We determine the curvature of the (pseudo)critical line of QCD with $n_f$=2+1\nstaggered fermions at nonzero temperature and quark density, by analytic\ncontinuation from imaginary chemical potentials. Monte Carlo simulations are\nperformed adopting the HISQ/tree action discretization, as implemented in the\ncode by the MILC collaboration, suitably modified to include a nonzero\nimaginary baryon chemical potential. We work on a line of constant physics, as\ndetermined in Ref.\\cite{Bazavov:2011nk}, adjusting the couplings so as to keep\nthe strange quark mass $m_s$ fixed at its physical value, with a light to\nstrange mass ratio $m_l/m_s=1/20$. In the present investigation we set the\nchemical potential at the same value for the three quark species,\n$\\mu_l=\\mu_s\\equiv \\mu$. We explore lattices of different spatial extensions,\n$16^3\\times 6$ and $24^3\\times 6$, to check for finite size effects, and\npresent results on a $32^3 \\times 8$ lattice, to check for finite cut-off\neffects. We discuss our results for the curvature $\\kappa$ of the critical line\nat $\\mu = 0$, which indicate $\\kappa=0.018(4)$, and compare them with previous\nlattice determinations by alternative methods and with experimental\ndeterminations of the freeze-out curve."
    },
    {
        "anchor": "S-parameter and vector decay constant in QCD with eight fundamental\n  fermions: SU(3) gauge theory with eight massless fundamental fermions seems to be near\nthe conformal boundary, and is a candidate theory of walking technicolor. Along\nthe series of study by LatKMI collaboration using HISQ fermions, S-parameter\nand vector decay constant, which provide important constraints in the model of\nelectroweak symmetry breaking, are calculated for this theory. Use of various\nvolumes allows a systematic investigation of finite volume effects. A strong\nsensitivity of the S-parameter to the volume is found.",
        "positive": "On the phase diagram and the singlet scalar channel in Yang-Mills-Higgs\n  theory: Yang-Mills-Higgs theory is quite a remarkable theory in that it shows very\ndifferent behaviors without phase transitions. It is dominated by the\nBrout-Englert-Higgs mechanism in some domain of the phase diagram, while it is\nessentially QCD-like in another. It is expected that albeit there is no\nqualitative difference, there are substantially quantitative differences\nthroughout the spectrum. This is investigated using lattice theory for the case\nof the scalar singlet channel for more than a hundred different points in the\nphase diagram. It is found that the results deviate partly substantially from\nthe expectations in some cases, but in others justify the picture of a weakly\ninteracting theory - even in cases of rather strong interactions at the\nultraviolet cutoff."
    },
    {
        "anchor": "Spontaneous chiral-symmetry breaking of lattice QCD with massless\n  dynamical quarks: One of the most challenging issues in QCD is the investigation of spontaneous\nchiral-symmetry breaking, which is characterized by the non-vanishing chiral\ncondensate when the bare fermion mass is zero. In standard methods, one has to\nperform expensive lattice simulations at multiple bare quark masses, and employ\nsome modeled function to extrapolate the data to the chiral limit. This paper\napplies the probability distribution function method to computing the chiral\ncondensate in lattice QCD with massless dynamical quarks, without any ambiguous\nmass extrapolation. The results for staggered quarks indicates that the method\nmight be a more efficient alternative for investigating the spontaneous\nchiral-symmetry breaking in lattice QCD.",
        "positive": "Fixed Point Actions for Wilson Fermions: Iterating renormalization group transformations for lattice fermions the\nWilson action is driven to fixed points of the renormalization group. A line of\nfixed points is found and the fixed point actions are computed analytically.\nThey are local and may be used to improve scaling in lattice QCD. The action at\nthe line's endpoint is chirally invariant and still has no fermion doubling.\nThe Nielsen-Ninomiya theorem is evaded because in this case the fixed point\naction is nonlocal. The use of this action for a construction of lattice chiral\nfermions is discussed."
    },
    {
        "anchor": "Nucleon and Pion Form Factors from $N_f=2+1$ Anisotropic Lattices: We report a recent lattice-QCD calculation of nucleon and pion\nelectromagnetic form factors and nucleon axial form factors, with special\nemphasis on large $Q^2$. Conventional lattice form-factor calculations can only\nreach about 2.5 GeV$^2$, but in this work the transfer momentum is pushed as\nlarge as 6 GeV$^2$. Here, we demonstrate the results on 2+1-flavor anisotropic\nclover lattices for the nucleon and pion, comparing with low-$Q^2$ quantities,\nsuch as Dirac and Pauli radii, anomalous magnetic moments, $g_A$ and $M_A$. Our\napproach can be applied to isotropic lattices and lattices with smaller lattice\nspacing to achieve even larger-$Q^2$ form factors. The form factors are\nprocessed to obtain transverse charge and magnetization densities across\n2-dimensional impact-parameter space. These measurements could give important\ntheoretical input to experiments, such as those of JLab's 12-GeV program, and\nprovide insight into hadronic structure.",
        "positive": "Quark-anti-quark potentials from Nambu-Bethe-Salpeter amplitudes on\n  lattice: Quark--anti-quark (anti-q-q) potentials with finite quark masses are studied\nfrom the anti-q-q Nambu-Bethe-Salpeter (NBS) wave functions in quenched lattice\nQCD. With the use of a method which has been recently developed in the\nderivation of nuclear forces from lattice QCD, we derive the anti-q-q\npotentials from the NBS wave functions. We calculate the anti-q-q NBS wave\nfunctions in pseudo-scalar and vector channels for several quark masses. The\nderived potentials at each quark mass in both channels show linear plus Coulomb\nform. We also discuss the quark-mass and channel dependence of the anti-q-q\npotentials."
    },
    {
        "anchor": "SU(3) lattice QCD study of the gluon propagator in maximally Abelian\n  gauge: off-diagonal gluon mass generation and infrared Abelian dominance: We investigate gluon propagators and the effective mass of the gluon fields\nin the MA gauge with U(1)$_3 \\times$ U(1)$_8$ Landau gauge fixing in SU(3)\nlattice QCD. The Monte Carlo simulation is performed on $16^4$ at $\\beta$=5.7,\n5.8 and 6.0 and $32^4$ at $\\beta=$5.8 and 6.0 at the quenched level. To\ncalculate the propagators, we adopt a method to extract gauge fields from\nlink-variables analytically in the SU(3) case. The off-diagonal gluons behave\nas massive vector bosons with the approximate effective mass $M_{\\rm off}\n\\simeq 1.1 - 1.2 {\\rm GeV}$ in the region of $r = 0.3 - 0.8 {\\rm fm}$, and the\npropagation is limited within a short range. On the other hand, the diagonal\ngluons behave as light vector bosons with $M_{\\rm diag}\\simeq 0.3 {\\rm GeV} $\nand the propagation of diagonal gluons remains even in a large range. In this\nway, infrared Abelian dominance is shown in terms of short-range propagation of\noff-diagonal gluons. Furthermore, we investigate the functional form of the\noff-diagonal gluon propagator. The functional form is well described by the\nfour-dimensional Euclidean Yukawa-type function ${\\rm exp}(-m_{\\rm off} r)/r$\nwith $m_{\\rm off} = 1.3 -1.4 {\\rm GeV}$ for $r = 0.1- 0.8{\\rm fm}$. This also\nindicates that the spectral function of off-diagonal gluons has the\nnegative-value region.",
        "positive": "Two-flavor Simulations of the $\u03c1(770)$ and the Role of the $K\\bar K$\n  Channel: The $\\rho (770)$ meson is the most extensively studied resonance in lattice\nQCD simulations in two ($N_f=2$) and three ($N_f=2+1$) flavor formulations. We\nanalyze $N_f=2$ lattice scattering data using unitarized Chiral Perturbation\nTheory, allowing not only for the extrapolation in mass but also in flavor,\n$N_f=2\\to N_f=2+1$. The flavor extrapolation requires information from a global\nfit to $\\pi\\pi$ and $\\pi K$ phase shifts from experiment. While the chiral\nextrapolation of $N_f=2$ lattice data leads to masses of the $\\rho(770)$ meson\nfar below the experimental one, we find that the missing $K\\bar{K}$ channel is\nable to explain this discrepancy."
    },
    {
        "anchor": "Flavor Twisted Boundary Conditions and the Nucleon Vector Current: Using flavor twisted boundary conditions, we study nucleon matrix elements of\nthe vector current. We twist only the active quarks that couple to the current.\nFinite volume corrections due to twisted boundary conditions are determined\nusing partially twisted, partially quenched, heavy baryon chiral perturbation\ntheory, which we develop for the graded group SU(7|5). Asymptotically these\ncorrections are exponentially small in the volume, but can become pronounced\nfor small twist angles. Utilizing the Breit frame does not mitigate volume\ncorrections to nucleon vector current matrix elements. The derived expressions\nwill allow for better controlled extractions of the isovector magnetic moment\nand the electromagnetic radii from simulations at zero lattice momentum. Our\nformalism, moreover, can be applied to any nucleon matrix elements.",
        "positive": "Lattice B-parameters for $\u0394S = 2$ and $\u0394I = 3/2$ Operators: We compute several matrix elements of dimension-six four-fermion operators\nand extract their B-parameters. The calculations have been performed with the\ntree-level Clover action at $\\beta = 6.0$. The renormalization constants and\nmixing coefficients of the lattice operators have been obtained\nnon-perturbatively. In the $\\MSbar$ renormalization scheme, at a\nrenormalization scale $\\mu \\simeq 2$ GeV, we find $B_K (B_9^{3/2}) = 0.66(11),\nB_7^{3/2} = 0.72(5)$ and $B_8^{3/2} = 1.03(3)$. The result for $B_8^{3/2}$ has\nimportant implications for the calculation of $\\epsilon^\\prime / \\epsilon$."
    },
    {
        "anchor": "Monte Carlo study of Lefschetz thimble structure in one-dimensional\n  Thirring model at finite density: We consider the one-dimensional massive Thirring model formulated on the\nlattice with staggered fermions and an auxiliary compact vector (link) field,\nwhich is exactly solvable and shows a phase transition with increasing the\nchemical potential of fermion number: the crossover at a finite temperature and\nthe first order transition at zero temperature. We complexify its\npath-integration on Lefschetz thimbles and examine its phase transition by\nhybrid Monte Carlo simulations on the single dominant thimble. We observe a\ndiscrepancy between the numerical and exact results in the crossover region for\nsmall inverse coupling $\\beta$ and/or large lattice size $L$, while they are in\ngood agreement at the lower and higher density regions. We also observe that\nthe discrepancy persists in the continuum limit keeping the temperature finite\nand it becomes more significant toward the low-temperature limit. This\nnumerical result is consistent with our analytical study of the model's thimble\nstructure. And these results imply that the contributions of subdominant\nthimbles should be summed up in order to reproduce the first order transition\nin the low-temperature limit.",
        "positive": "Search for a continuum limit of the PMS phase: Previous studies of a simple four-fermion model with staggered fermions in 3D\nhave shown the existence of an exotic quantum critical point, where one may be\nable to define a continuum limit of the Paramagnetic Strong Phase (or the PMS\nphase). We believe the existence of the critical point suggests a new mechanism\nfor generating fermion masses. In this work we begin the search for this\nquantum critical point in 4D by extending the 3D model to 4D. Unlike in 3D, now\nwe do find evidence for an intermediate spontaneously broken phase (FM phase)\nand are able compute the phase boundaries accurately. In terms of the bare\ncoupling, the width of the intermediate region appears to be quite small."
    },
    {
        "anchor": "Understanding CP violation in lattice QCD: It is pointed out that any CP violation which may be found in lattice QCD\nwith a chiral phase in the fermion mass term cannot be relevant for the\ncontinuum theory. CP is classically conserved in the corresponding continuum\ntheory and is non-anomalous.",
        "positive": "The Higgs Model with a Complex Ghost Pair: A higher derivative term is introduced in the kinetic energy of the Higgs\nLagrangian in the minimal Standard Model. A logically consistent and {\\it\nfinite} field theory is obtained when some excitations of the Higgs field are\nquantized with indefinite metric in the Hilbert space. The Landau ghost\nphenomenon of the conventional triviality problem is replaced by the state\nvectors of a complex ghost pair at a finite mass scale with observable physical\nconsequences. It is shown that the ghost states exhibit unusual resonance\nproperties and correspond to a complex conjugate pair of Pauli-Villars\nregulator masses in the euclidean path integral formulation of the theory. An\nargument is given that microscopic acausality effects associated with the ghost\npair remain undetectable in scattering processes with realistic wave packects,\nand the S-matrix should exhibit unitarity in the observable sector of the\nHilbert space. Part One of Extended UCSD-PTH 92-40"
    },
    {
        "anchor": "Quantum Monte Carlo for Gauge Fields and Matter without the Fermion\n  Determinant: Ab-initio Monte Carlo simulations of strongly-interacting fermionic systems\nare plagued by the fermion sign problem, making the non-perturbative study of\nmany interesting regimes of dense quantum matter, or of theories of odd numbers\nof fermion flavors, challenging. Moreover, typical fermion algorithms require\nthe computation (or sampling) of the fermion determinant. We focus instead on\nthe meron cluster algorithm, which can solve the fermion sign problem in a\nclass of models without involving the determinant. We develop and benchmark new\nmeron algorithms to simulate fermions coupled to $\\mathbb{Z}_2$ and $U(1)$\ngauge fields in the presence of appropriate four-fermi interactions. Such\nalgorithms can be used to uncover potential exotic properties of matter,\nparticularly relevant for quantum simulator experiments. We demonstrate the\nemergence of the Gauss' Law at low temperatures for a $U(1)$ model in\n$(1+1)-$d.",
        "positive": "Perturbative matching of lattice and continuum heavy-light currents with\n  NRQCD heavy quarks: The temporal and spatial components of the heavy-light vector current and the\nspatial components of the axial current are expressed in terms of\nlattice-regulated operators suitable for simulations of B and D mesons. The\ncurrents are constructed by matching the appropriate scattering amplitudes in\ncontinuum QCD and a lattice model to one-loop order in perturbation theory. In\nthe lattice theory, the heavy quarks are treated using the nonrelativistic\n(NRQCD) formulation and the light quarks are described by the tadpole-improved\nclover action. The light quarks are treated as massless. Our currents include\nrelativistic and discretization corrections through O(alpha_s/M, a alpha_s),\nwhere M is the heavy-quark mass, a is the lattice spacing, and alpha_s is the\nQCD coupling. As in our previous construction of the temporal component of the\nheavy-light axial current, mixing between several lattice operators is\nencountered at one-loop order, and O(a alpha_s) dimension-four improvement\nterms are identified."
    },
    {
        "anchor": "Finding the effective Polyakov line action for SU(3) gauge theories at\n  finite chemical potential: Motivated by the sign problem, we calculate the effective Polyakov line\naction corresponding to certain SU(3) lattice gauge theories on a ${16^3 \\times\n6}$ lattice via the \"relative weights\" method introduced in our previous\narticles. The calculation is carried out at $\\beta=5.6,5.7$ for the pure gauge\ntheory, and at $\\beta=5.6$ for the gauge field coupled to a relatively light\nscalar particle. In the latter example we determine the effective theory also\nat finite chemical potential, and show how observables relevant to phase\nstructure can be computed in the effective theory via mean field methods. In\nall cases a comparison of Polyakov line correlators in the effective theory and\nthe underlying lattice gauge theory, computed numerically at zero chemical\npotential, shows accurate agreement down to correlator magnitudes of order\n$10^{-5}$. We also derive the effective Polyakov line action corresponding to a\ngauge theory with heavy quarks and large chemical potential, and apply mean\nfield methods to extract observables.",
        "positive": "Chiral Fermions on the Lattice: In the last century the non-perturbative regularization of chiral fermions\nwas a long-standing problem. We review how this problem was finally overcome by\nthe formulation of a modified but exact form of chiral symmetry on the lattice.\nThis also provides a sound definition of the topological charge of lattice\ngauge configurations. We illustrate a variety of applications to QCD in the p-,\nthe epsilon- and the delta-regime, where simulation results can now be related\nto Random Matrix Theory and Chiral Perturbation Theory. The latter contains Low\nEnergy Constants as free parameters, and we comment on their evaluation from\nfirst principles of QCD."
    },
    {
        "anchor": "Series expansions without diagrams: We discuss the use of recursive enumeration schemes to obtain low and high\ntemperature series expansions for discrete statistical systems. Using linear\ncombinations of generalized helical lattices, the method is competitive with\ndiagramatic approaches and is easily generalizable. We illustrate the approach\nusing the Ising model and generate low temperature series in up to five\ndimensions and high temperature series in three dimensions. The method is\ngeneral and can be applied to any discrete model. We describe how it would work\nfor Potts models.",
        "positive": "Nuclear Physics Review: Anchoring low-energy nuclear physics to the fundamental theory of strong\ninteractions remains an outstanding challenge. I review the current progress\nand challenges of the endeavor to use lattice QCD to bridge this connection.\nThis is a particularly exciting time for this line of research as demonstrated\nby the spike in the number of different collaborative efforts focussed on this\nproblem and presented at this conference. I first digress and discuss the 2013\nKen Wilson Award."
    },
    {
        "anchor": "Glueballs on S^3: For SU(2) gauge theory on the three-sphere we study the dynamics of the\nlow-energy modes. By explicitely integrating out the high-energy modes, the\none-loop correction to the hamiltonian for this problem is obtained. After\nimposing the $\\theta$-dependence through boundary conditions in configuration\nspace, we obtain the glueball spectrum of the effective theory with a\nvariational method.",
        "positive": "Perturbative Matching of the staggered four-fermion operators for e'/e: Using staggered fermions, we calculate the perturbative corrections to the\nbilinear and four-fermion operators that are used in the numerical study of\nweak matrix elements for $\\epsilon'/\\epsilon$. We present results for one-loop\nmatching coefficients between continuum operators, calculated in the Naive\nDimensional Regularization (NDR) scheme, and gauge invariant staggered fermion\noperators. These results, combined with existing results for penguin diagrams,\nprovide the complete one-loop renormalization of the staggered four-fermion\noperators."
    },
    {
        "anchor": "Screening in two-dimensional gauge theories: We analyze the problem of screening in 1+1 dimensional gauge theories. Using\nQED2 as a warm-up for the non-abelian models we show the mechanism of the\nstring breaking, in particular the vanishing overlap of the Wilson loops to the\nbroken-string ground state that has been conjectured in higher-dimensional\nanalyses. We attempt to extend our analysis to non-integer charges in the\nquenched and unquenched cases, in pursuit of the numerical check of a renowned\nresult for the string tension between arbitrarily-charged fermions in the\nmassive Schwinger model.",
        "positive": "Fixed point actions for SU(3) gauge theory: We summarize our recent work on the construction and properties of fixed\npoint (FP) actions for lattice $SU(3)$ pure gauge theory. These actions have\nscale invariant instanton solutions and their spectrum is exact through\n1--loop, i.e. in their physical predictions there are no $a^n$ nor $g^2 a^n$\ncut--off effects for any $n$. We present a few-parameter approximation to a\nclassical FP action which is valid for short correlation lengths. We perform a\nscaling test of the action by computing the quantity $G = L \\sqrt{\\sigma(L)}$,\nwhere the string tension $\\sigma(L)$ is measured from the torelon mass $\\mu = L\n\\sigma(L)$, on lattices of fixed physical volume and varying lattice spacing\n$a$. While the Wilson action shows scaling violations of about ten per cent,\nthe approximate fixed point action scales within the statistical errors for $\n1/2 \\ge aT_c$."
    },
    {
        "anchor": "Strongly Interacting Higgs Sector in the Minimal Standard Model?: The triviality Higgs mass bound is studied {\\it without} lattice regulator in\nthe spontaneously broken phase of the four dimensional O(4) symmetric scalar\nfield theory with quartic self-interaction. A higher derivative term is\nintroduced in the kinetic energy of the Lagrangian to keep quantum fluctuations\nfinite while preserving all the symmetries of the model. When viewed as a {\\it\nfinite} field theory in continuum space-time, some excitations of the Higgs\nfield have to be quantized with indefinite metric in the Hilbert space. It is\nshown that the associated ghost particles, which exhibit unusual resonance\nproperties, correspond to a complex conjugate pair of Pauli-Villars regulator\nmasses in the euclidean path integral formulation. The phase diagram of the\nO(4) model is determined in a Monte Carlo simulation which interpolates between\nthe hypercubic lattice regulator and the higher derivative regulator in\ncontinuum space-time. The same method can be used to calculate the triviality\nHiggs mass bound without lattice artifacts. In a large-N analysis, when\ncompared with a hypercubic lattice, we find a relative increase in the\ntriviality bound of the higher derivative regulator suggesting a strongly\ninteracting Higgs",
        "positive": "Partially Quenched Chiral Condensates from the Replica Method: A large-N_f expansion is used to compute the partially quenched chiral\ncondensate of QCD in the microscopic finite-volume scaling region."
    },
    {
        "anchor": "Quenched Hadron Spectrum and Decay Constants on the lattice: In this talk we present the results obtained from a study of ${\\cal O}(2000)$\n(quenched) lattice configurations from the APE collaboration, at\n$6.0\\le\\beta\\le 6.4$, using both the Wilson and the SW-Clover fermion action.\nWe determine the light hadronic spectrum and the meson decay constants. For the\nlight-light systems we find an agreement with the experimental data of $\\sim\n5%$ for mesonic masses and $\\sim 10%-15%$ for baryonic masses and pseudoscalar\ndecay constants; a larger deviation is present for the vector decay constants.\nFor the heavy-light decay constants we find $f_{D_s}=237 \\pm 16 MeV, f_{D} =\n221 \\pm 17 MeV (f_{D_s}/f_D=1.07(4)), f_{B_s} = 205 \\pm 35 MeV, f_{B} = 180 \\pm\n32 MeV (f_{B_s}/f_B=1.14(8))$, in good agreement with previous estimates.",
        "positive": "Heavy-light physics using NRQCD-staggered actions: One leading source of uncertainty in the lattice computation of semi-leptonic\nform factors in B decay, and to a lesser extent B meson decay constants, comes\nfrom the extrapolation of the light quark mass to the physical up/down mass.\nThis talk presents first explorations of simulating the light quark with\nstaggered fermion actions, which are free of the spurious zero modes that\neffect Wilson-like Dirac operators and are less costly. Methods for fitting to\nEuclidean-time NRQCD-staggered meson propagators are discussed, and some\npreliminary spectrum results are presented."
    },
    {
        "anchor": "Holography for Ising spins on the hyperbolic plane: Motivated by the AdS/CFT correspondence, we use Monte Carlo simulation to\ninvestigate the Ising model formulated on tessellations of the two-dimensional\nhyperbolic disk. We focus in particular on the behavior of boundary-boundary\ncorrelators, which exhibit power-law scaling both below and above the bulk\ncritical temperature indicating scale invariance of the boundary theory at any\ntemperature. This conclusion is strengthened by a finite-size scaling analysis\nof the boundary susceptibility which yields a scaling exponent consistent with\nthe scaling dimension extracted from the boundary correlation function. This\nobservation provides evidence that the connection between continuum boundary\nconformal symmetry and isometries of the bulk hyperbolic space survives for\nsimple interacting field theories even when the bulk is approximated by a\ndiscrete tessellation.",
        "positive": "Current matrix element in HAL QCD's wave function equivalent potential\n  method: We give a formula to calculate a matrix element of a conserved current in the\neffective quantum mechanics defined by the wave function equivalent potentials\nproposed by HAL QCD collaboration. As a first step, a non-relativistic field\ntheory with two channel coupling is considered as the original theory, with\nwhich a wave function equivalent HAL QCD potential is obtained in a closed\nanalytic form. The external field method is used to derive the formula by\ndemanding that the result should agree with the original theory. With this\nformula, the matrix element is obtained by sandwiching the effective current\noperator between the left and the right eigen functions of the effective\nHamiltonian associated with the HAL QCD potential. In addition to the naive\none-body current, the effective current operator contains an additional\ntwo-body term emerging from the degrees of freedom which has been integrated\nout."
    },
    {
        "anchor": "Fermion Determinants: Some Recent Analytic Results: The use of known analytic results for the continuum fermion determinants in\nQCD and QED as benchmarks for zero lattice spacing extrapolations of lattice\nfermion determinants is proposed. Specifically, they can be used as a check on\nthe universality hypothesis relating the continuum limits of the na\\\"{\\i}ve,\nstaggered and Wilson fermion determinants.",
        "positive": "Thin Absolute Villains: We perform simulations of an absolute value version of the Villain model on\nphi3 and phi4 Feynman diagrams, ``thin'' 3-regular and 4-regular random graphs.\nThe phi4 results are in excellent quantitative agreement with the exact\ncalculations by Dorey and Kurzepa for an annealed ensemble of thin graphs, in\nspite of simulating only a single graph of each size. We also derive exact\nresults for an annealed ensemble of phi3 graphs and again find excellent\nagreement with the numerical data for single phi3 graphs.\n  The simulations confirm the picture of a mean field vortex transition which\nis suggested by the analytical results. Further simulations on phi5 and phi6\ngraphs and of the standard XY model on phi3 graphs confirm the universality of\nthese results. The calculations of Dorey and Kurzepa were based on\nreinterpreting the large orders behaviour of the anharmonic oscillator in a\nstatistical mechanical context so we also discuss briefly the interpretation of\nsingularities in the large orders behaviour in other models as phase\ntransitions."
    },
    {
        "anchor": "Branes in the 5D Abelian Higgs Model: We find 3-brane Higgs and Coulomb phases in the 5D Abelian Higgs Model and\ndetermine the transition surfaces that separate them from the usual bulk\nphases.",
        "positive": "Fixed point action and topological charge for SU(2) gauge theory: We present a theoretically consistent definition of the topological charge\noperator based on renormalization group arguments. Results of the\n  measurement of the topological susceptibility at zero and finite temperature\nfor SU(2) gauge theory are presented."
    },
    {
        "anchor": "Background field method in the gradient flow: In perturbative consideration of the Yang--Mills gradient flow, it is useful\nto introduce a gauge non-covariant term (\"gauge-fixing term\") to the flow\nequation that gives rise to a Gaussian damping factor also for gauge degrees of\nfreedom. In the present paper, we consider a modified form of the gauge-fixing\nterm that manifestly preserves covariance under the background gauge\ntransformation. It is shown that our gauge-fixing term does not affect\ngauge-invariant quantities as the conventional gauge-fixing term. The\nformulation thus allows a background gauge covariant perturbative expansion of\nthe flow equation that provides, in particular, a very efficient computational\nmethod of expansion coefficients in the small flow time expansion. The\nformulation can be generalized to systems containing fermions.",
        "positive": "Efficient integration of gradient flow in lattice gauge theory and\n  properties of low-storage commutator-free Lie group methods: The smoothing procedure known as the gradient flow that suppresses\nultraviolet fluctuations of gauge fields plays an important role in lattice\ngauge theory calculations. In particular, this procedure is often used for\nhigh-precision scale setting and renormalization of operators. The gradient\nflow equation is defined on the SU(3) manifold and therefore requires\ngeometric, or structure-preserving, integration methods to obtain its numerical\nsolutions. We examine the properties and origins of the three-stage third-order\nexplicit Runge-Kutta Lie group integrator commonly used in the lattice gauge\ntheory community, demonstrate its relation to 2N-storage classical Runge-Kutta\nmethods and explore how its coefficients can be tuned for optimal performance\nin integrating the gradient flow. We also compare the performance of the tuned\nmethod with two third-order variable step size methods. Next, based on the\nrecently established connection between low-storage Lie group integrators and\nclassical 2N-storage Runge-Kutta methods, we study two fourth-order low-storage\nmethods that provide a computationally efficient alternative to the commonly\nused third-order method while retaining the convenient iterative property of\nthe latter. Finally, we demonstrate that almost no coding effort is needed to\nimplement the low-storage Lie group methods into existing gradient flow codes."
    },
    {
        "anchor": "Mass spectrum of 1-+ exotic mesons from lattice QCD: Time correlation functions of a hybrid exotic meson operator, with JPC=1-+,\ngenerated in quenched lattice QCD are subjected to a (Bayesian) maximum entropy\nanalysis. Five distinct spectral levels are uncovered. Their extrapolation into\nthe physical pion mass region suggests a possible relationship to\nexperimentally known states pi1(1400) and pi1(1600), and also to a state in the\n2 GeV region carrying the same quantum numbers.",
        "positive": "Tuning HMC parameters with gradients: We investigate the effectiveness of tuning HMC parameters using information\nfrom the gradients of the HMC acceptance probability with respect to the\nparameters. In particular, the optimization of the trajectory length and\nparameters for higher order integrators will be studied in the context of pure\ngauge and dynamical fermion actions."
    },
    {
        "anchor": "Microcanonical cluster algorithms: I propose a numerical simulation algorithm for statistical systems which\ncombines a microcanonical transfer of energy with global changes in clusters of\nspins. The advantages of the cluster approach near a critical point augment the\nspeed increases associated with multi-spin coding in the microcanonical\napproach. The method also provides a limited ability to tune the average\ncluster size.",
        "positive": "Controlling quark mass determinations non-perturbatively in\n  three-flavour QCD: The determination of quark masses from lattice QCD simulations requires a\nnon-perturbative renormalization procedure and subsequent scale evolution to\nhigh energies, where a conversion to the commonly used MS-bar scheme can be\nsafely established. We present our results for the non-perturbative running of\nrenormalized quark masses in Nf=3 QCD between the electroweak and a hadronic\nenergy scale, where lattice simulations are at our disposal. Recent theoretical\nadvances in combination with well-established techniques allows to follow the\nscale evolution to very high statistical accuracy, and full control of\nsystematic effects."
    },
    {
        "anchor": "On the screening of the potential between adjoint sources in $QCD_3$: We calculate the potential between adjoint sources in $SU(2)$ pure gauge\ntheory in three dimensions. We investigate whether the potential saturates at\nlarge separations due to the creation of a pair of gluelumps, colour-singlet\nstates formed when glue binds to an adjoint source.",
        "positive": "Finite-Size Scaling of Vector and Axial Current Correlators: Using quenched chiral perturbation theory, we compute the long-distance\nbehaviour of two-point functions of flavour non-singlet axial and vector\ncurrents in a finite volume, for small quark masses, and at a fixed gauge-field\ntopology. We also present the corresponding predictions for the unquenched\ntheory at fixed topology. These results can in principle be used to measure the\nlow-energy constants of the chiral Lagrangian, from lattice simulations in\nvolumes much smaller than one pion Compton wavelength. We show that quenching\nhas a dramatic effect on the vector correlator, which is argued to vanish to\nall orders, while the axial correlator appears to be a robust observable only\nmoderately sensitive to quenching."
    },
    {
        "anchor": "A fully non-perturbative charm-quark tuning using machine learning: We present a relativistic heavy-quark action tuning for the charm sector on\nensembles generated by the CLS consortium. We tune a particular 5-parameter\naction in an entirely non-perturbative and -- up to the chosen experimental\ninput -- model-independent way using machine learning and the continuum\nexperimental charmonium ground-state masses with various quantum numbers. In\nthe end we are reasonably successful; obtaining a set of simulation parameters\nthat we then verify produces the expected spectrum. In the future, we will use\nthis action for finite-volume calculations of hadron-hadron scattering.",
        "positive": "$K_L-K_S$ mass difference from lattice QCD: We report on the first complete calculation of the $K_L-K_S$ mass difference,\n$\\Delta M_K$, using lattice QCD. The calculation is performed on a 2+1 flavor,\ndomain wall fermion ensemble with a 330MeV pion mass and a 575 MeV kaon mass.\nWe use a quenched charm quark with a 949 MeV mass to implement\nGlashow-Iliopoulos-Maiani cancellation. For these heavier-than-physical\nparticle masses, we obtain $\\Delta M_K =3.19(41)(96)\\times 10^{-12}$ MeV, quite\nsimilar to the experimental value. Here the first error is statistical and the\nsecond is an estimate of the systematic discretization error. An interesting\naspect of this calculation is the importance of the disconnected diagrams, a\ndramatic failure of the OZI rule."
    },
    {
        "anchor": "Current Renormalisation Constants with an O(a)-improved Fermion Action: Using chiral Ward identities, we determine the renormalisation constants of\nbilinear quark operators for the Sheikholeslami-Wohlert action lattice at\nbeta=6.2. The results are obtained with a high degree of accuracy. For the\nvector current renormalisation constant we obtain Z_V=0.817(2)(8), where the\nfirst error is statistical and the second is due to mass dependence of Z_V.\nThis is close to the perturbative value of 0.83. For the axial current\nrenormalisation constant we obtain Z_A = 1.045(+10 -14), significantly higher\nthan the value obtained in perturbation theory. This is shown to reduce the\ndifference between lattice estimates and the experimental values for the\npseudoscalar meson decay constants, but a significant discrepancy remains. The\nratio of pseudoscalar to scalar renormalisation constants, Z_P/Z_S, is less\nwell determined, but seems to be slightly lower than the perturbative value.",
        "positive": "Semileptonic decays of K and D mesons in 2+1 flavor QCD: The experimentally measured rates of the semileptonic decays K -> pi l nu and\nD -> K(pi) l nu can be combined with lattice calculations of the associated\nform factors to precisely extract the CKM matrix elements |V_{us}| and\n|V_{cs(d)}|. We report on the status of form factor calculations with Fermilab\ncharm quarks and staggered light quarks on the 2+1 flavor asqtad staggered MILC\nensembles. Analysis of data for the D -> pi l nu form factor provides a\nnontrivial test of our methods via comparison with CLEO data. We discuss the\nuse of HISQ valence quarks to calculate the K -> pi l nu form factor f_+^{K\npi}(0) and describe tests of our method."
    },
    {
        "anchor": "HotQCD on Multi-GPU Systems: We present $\\texttt{SIMULATeQCD}$, HotQCD's software for performing lattice\nQCD calculations on GPUs. Started in late 2017 and intended as a full\nreplacement of the previous single GPU lattice QCD code used by the HotQCD\ncollaboration, our software has been developed into an extensive framework for\nlattice QCD calculations distributed on multiple GPUs over many compute nodes.\nThe code is built on C++, CUDA, and MPI and leverages modern C++ language\nfeatures to provide high-level data structures, objects, and algorithms that\nallow users to express lattice QCD calculations in an intuitive way without\nsacrificing performance. Implemented algorithms range from gradient flow,\ncorrelator measurements, and mixed precision conjugate gradient solvers all the\nway to full HISQ gauge field configuration generation using RHMC. After\nsuccessful deployment in large-scale computing projects, we want to share the\nresult of our efforts with the lattice QCD community by making it publicly\navailable. In these proceedings, we will present some of the key features of\nour code, demonstrate its ease of use, and show benchmarks of performance\ncritical kernels on state-of-the-art supercomputers.",
        "positive": "Lattice Fermions without Doublers: By placing fermions only on the even sites of a lattice, one may halve the\nmomentum spectrum and construct a theory without doublers. The interaction is\nnonlocal. The fermion propagator is not a sparse matrix, but because the\nunwanted fermionic states are absent from the formalism, it is 256 times\nsmaller than the usual propagator."
    },
    {
        "anchor": "Lattice QCD Study for Confinement and Hadrons: Using SU(3) lattice QCD, we perform the detailed studies of the three-quark\nand the multi-quark potentials. From the accurate calculation for more than 300\ndifferent patterns of 3Q systems, the static ground-state 3Q potential $V_{\\rm\n3Q}^{\\rm g.s.}$ is found to be well described by the Coulomb plus Y-type linear\npotential (Y-Ansatz) within 1%-level deviation. As a clear evidence for\nY-Ansatz, Y-type flux-tube formation is actually observed on the lattice in\nmaximally-Abelian projected QCD. For about 100 patterns of 3Q systems, we\nperform the accurate calculation for the 1st excited-state 3Q potential $V_{\\rm\n3Q}^{\\rm e.s.}$ by diagonalizing the QCD Hamiltonian in the presence of three\nquarks, and find a large gluonic-excitation energy $\\Delta E_{\\rm 3Q} \\equiv\nV_{\\rm 3Q}^{\\rm e.s.}-V_{\\rm 3Q}^{\\rm g.s.}$ of about 1 GeV, which gives a\nphysical reason of the success of the quark model. $\\Delta E_{\\rm 3Q}$ is found\nto be reproduced by the ``inverse Mercedes Ansatz'', which indicates a\ncomplicated bulk excitation for the gluonic-excitation mode. We study also the\ntetra-quark and the penta-quark potentials in lattice QCD, and find that they\nare well described by the OGE Coulomb plus multi-Y type linear potential, which\nsupports the flux-tube picture even for the multi-quarks.",
        "positive": "Lattice QCD - A guide for people who want results: Lattice QCD was invented thirty years ago but only in the last few years has\nit finally fulfilled its promise as a precision tool for calculations in hadron\nphysics. This review will cover the fundamentals of discretising QCD onto a\nspace-time lattice and how to reduce the errors associated with the\ndiscretisation. This 'improvement' is the key that has made the enormous\ncomputational task of a lattice QCD calculation tractable and enabled us to\nreach the recent milestone of precision calculations of simple 'gold-plated'\nhadron masses. Accurate decay matrix elements, such as those for leptonic and\nsemileptonic decays of heavy mesons needed by the B factory experimental\nprogramme, are now within sight. I will describe what goes into such\ncalculations and what the future prospects and limitations are."
    },
    {
        "anchor": "Methods for Pseudoscalar Flavour-Singlet Mesons with Staggered Fermions: We present the first 2+1 flavour lattice QCD calculations of pseudoscalar\nflavour-singlet propagators using improved staggered fermions. We explore the\nrelevant techniques and discuss prospects for the larger scale studies now in\nprogress. The disconnected correlator is shown to have a highly non-Gaussian\ndistribution and reliable estimates of the errors require care.",
        "positive": "Nucleons and parity doubling across the deconfinement transition: It is expected that nucleons and their parity partners become degenerate when\nchiral symmetry is restored. We investigate this question in the context of the\nthermal transition from the hadronic phase to the quark-gluon plasma, using\nlattice QCD simulations with N_f=2+1 flavours. We observe a clear sign of\nparity doubling in the quark-gluon plasma. Besides, we find that the nucleon\nground state is, within the uncertainty, largely independent of the\ntemperature, whereas temperature effects are substantial in the negative-parity\n(N^*) channel, already in the confined phase."
    },
    {
        "anchor": "Lattice-continuum relations for 3d SU(N)+Higgs theories: 3d lattice studies have recently attracted a lot of attention, especially in\nconnection with finite temperature field theories. One ingredient in these\nstudies is a perturbative computation of the 2-loop lattice counterterms, which\nare exact in the continuum limit. We extend previous such results to SU(N)\ngauge theories with Higgs fields in the fundamental and adjoint\nrepresentations. The fundamental SU(3)xSU(2) case might be relevant for the\nelectroweak phase transition in the MSSM, and the adjoint case for the GUT\nphase transition and for QCD in the high temperature phase. We also revisit the\nstandard SU(2)xU(1) and U(1) theories.",
        "positive": "Chiral behavior of $K \\to \u03c0l \u03bd$ decay form factors in lattice QCD\n  with exact chiral symmetry: We calculate the form factors of the $K \\to \\pi l \\nu$ semileptonic decays in\nthree-flavor lattice QCD, and study their chiral behavior as a function of the\nmomentum transfer and the Nambu-Goldstone boson masses. Chiral symmetry is\nexactly preserved by using the overlap quark action, which enables us to\ndirectly compare the lattice data with chiral perturbation theory (ChPT). We\ngenerate gauge ensembles at a lattice spacing of 0.11fm with four pion masses\ncovering 290-540 MeV and a strange quark mass m_s close to its physical value.\nBy using the all-to-all quark propagator, we calculate the vector and scalar\nform factors with high precision. Their dependence on m_s and the momentum\ntransfer is studied by using the reweighting technique and the twisted boundary\nconditions for the quark fields. We compare the results for the semileptonic\nform factors with ChPT at next-to-next-to leading order in detail. While many\nlow-energy constants appear at this order, we make use of our data of the light\nmeson electromagnetic form factors in order to control the chiral\nextrapolation. We determine the normalization of the form factors as f_+(0) =\n0.9636(36)(+57/-35), and observe reasonable agreement of their shape with\nexperiment."
    },
    {
        "anchor": "The Light Hadron Mass Spectrum with Non-Perturbatively O(a) Improved\n  Wilson Fermions: We compute the light hadron mass spectrum in quenched lattice QCD at $\\beta =\n6.0$ using the Sheikholeslami-Wohlert fermionic action. The calculation is done\nfor several choices of the coefficient $c_{SW}$, including $c_{SW} = 0$ and the\nrecently proposed optimal value $c_{SW} = 1.769$. We find that the individual\nmasses change by up to 30\\% under $O(a)$ improvement. The spectrum calculation\nsuggests $c_{SW} \\approx 1.4$ for the optimal value of the coefficient.",
        "positive": "Nonperturbative tuning of $O(a^2)$ improved staggered fermions: We perform a nonperturbative tuning of the coefficients in the $O(a^2)$\nimproved action for staggered fermions. The mass splitting for the pions of\ndifferent doubler flavor is used as a measure of the symmetry breaking effects\nintroduced by $O(a^2)$ discretization errors. We find that the flavor\nnondegeneracy can be somewhat reduced but not eliminated by such a tuning,\nindicating the need for new terms in the action to reduce the nondegeneracy."
    },
    {
        "anchor": "DIS Structure Functions in Lattice QCD: In this talk I present the complete 1-loop perturbative computation of the\nrenormalization constants and mixing coefficients of quark and gluon lattice\noperators of rank two and three whose hadronic elements enter in the\ndetermination of the first and second moment of Deep Inelastic Scattering\nStructure Functions, making use of the nearest-neighbor improved\n``clover-leaf'' lattice QCD action.\n  To perform the huge amount of calculations required for the evaluation of all\nthe relevant Feynman diagrams, extensive use of symbolic manipulation languages\nlike Schoonschip and Form has been made.",
        "positive": "Gluon gravitational form factors of the nucleon and the pion from\n  lattice QCD: A future Electron-Ion Collider will enable the gluon contributions to the\ngravitational form factors of the proton to be constrained experimentally for\nthe first time. Here, the first calculation of these form factors from lattice\nQuantum Chromodynamics is presented. The calculations use a\nlarger-than-physical value of the light quark mass corresponding to $m_\\pi \\sim\n450$ MeV. All three form factors, which encode the momentum-dependence of the\nlowest moment of the spin independent gluon generalised parton distributions\nand are related to different components of the energy-momentum tensor, are\nresolved. In particular, the gluon $D$-term form factor, related to the\npressure distribution inside the nucleon, is determined for the first time. The\ngluon contributions to the two gravitational form factors of the pion are also\ndetermined, and are compared to existing lattice determinations of the quark\ncontributions to the gravitational form factors and to phenomenology."
    },
    {
        "anchor": "Twisted finite-volume corrections to $K_{l3}$ decays with\n  partially-quenched and rooted-staggered quarks: The determination of $|V_{us}|$ from kaon semileptonic decays requires the\nvalue of the form factor $f_+(q^2=0)$ which can be calculated precisely on the\nlattice. We provide the one-loop partially quenched chiral perturbation theory\nexpressions both with and without including the effects of staggered quarks for\nall form factors at finite volume and with partially twisted boundary\nconditions for both the vector current and scalar density matrix elements at\nall $q^2$. We point out that at finite volume there are more form factors than\njust $f_+$ and $f_-$ for the vector current matrix element but that the Ward\nidentity is fully satisfied. The size of the finite-volume corrections at\npresent lattice sizes is small. This will help improve the lattice\ndetermination of $f_+(q^2=0)$ since the finite-volume error is the dominant\nerror source for some calculations. The size of the finite-volume corrections\nmay be estimated on a single lattice ensemble by comparing results for various\ntwist choices.",
        "positive": "Temperature dependence of electrical conductivity and dilepton rates\n  from hot quenched lattice QCD: We present new results on the continuum extrapolation of the vector current\ncorrelation function in the deconfined phase for three temperatures close to\nthe critical temperature utilizing quenched clover improved Wilson fermions and\nlight quark masses. A systematic analysis on multiple lattice spacing allows to\nperform the continuum limit of the correlation function and to extract spectral\nproperties in the continuum limit. These results provide constraints for the\nelectrical conductivity and the thermal dilepton rates in the quark gluon\nplasma for the given temperature range. In addition results on the continuum\nextrapolation at finite momenta related to thermal photon rates are presented."
    },
    {
        "anchor": "Lattice QCD, gauge fixing, and the transition to the perturbative regime: Perturbative QCD uses the Faddeev-Popov gauge-fixing procedure, which leads\nto ghosts and the local BRST invariance of the gauge-fixed perturbative QCD\naction. In the asymptotic regime, where perturbative QCD is relevant, Gribov\ncopies can be neglected. In the nonperturbative regime, one must adopt either a\nnonlocal Gribov-copy free gauge (e.g., Laplacian gauge) or attempt to maintain\nlocal BRST invariance at the expense of admitting Gribov copies. These issues\nare explored and discussed. In addition, the relationship between recent\nDyson-Schwinger based calculations of the infrared behavior of QCD Green's\nfunctions and the lattice calculation of these quantities is examined.",
        "positive": "The curvature of the chiral phase transition line for small values of\n  $\u03bc_B$: We present preliminary results from an ongoing calculation to determine the\ncurvature of the chiral phase transition line in the chiral limit along the\nlight-light, light-strange and strange-strange chemical potential directions.\nWe do this by studying the appropriate $\\mu$-derivatives of the chiral\ncondensate as a function of the quark mass and comparing them to the scaling\npredictions of $3d$-$O(N)$ theory. We work at a fixed lattice spacing,\n$N_\\tau=6$ and at four different quark masses $m_\\pi\\approx$ 140, 110, 90 and\n80 MeV. For the light quark curvature, we obtain a value\n0.03$\\leqslant\\kappa_{ll}\\leqslant$0.11. We also find that both strange and\nlight-strange curvatures are around an order of magnitude smaller. Currently,\nthe light-strange curvature is the least constrained curvature and could have\neither sign, though our results seem to prefer a slightly negative value."
    },
    {
        "anchor": "Luescher-Weisz algorithm for excited states of the QCD flux-tube: We present a version of the Luescher-Weisz multilevel algorithm ideally\nsuited for studying excited states of the QCD flux tube. While the original\nversion achieved error reduction only in the temporal direction, the new\nalgorithm reduces fluctuations in the sources as well. We report on the\nimplementation of this algorithm as well as improvement over the older method.\nWe also present first results, where we see a good agreement with theoretical\npredictions from bosonic string models.",
        "positive": "Overcoming exponential volume scaling in quantum simulations of lattice\n  gauge theories: Real-time evolution of quantum field theories using classical computers\nrequires resources that scale exponentially with the number of lattice sites.\nBecause of a fundamentally different computational strategy, quantum computers\ncan in principle be used to perform detailed studies of these dynamics from\nfirst principles. Before performing such calculations, it is important to\nensure that the quantum algorithms used do not have a cost that scales\nexponentially with the volume. In these proceedings, we present an interesting\ntest case: a formulation of a compact U(1) gauge theory in 2+1 dimensions free\nof gauge redundancies. A naive implementation onto a quantum circuit has a gate\ncount that scales exponentially with the volume. We discuss how to break this\nexponential scaling by performing an operator redefinition that reduces the\nnon-locality of the Hamiltonian. While we study only one theory as a test case,\nit is possible that the exponential gate scaling will persist for formulations\nof other gauge theories, including non-Abelian theories in higher dimensions."
    },
    {
        "anchor": "Backward running or absence of running from Creutz ratios: We extract the running coupling based on Creutz ratios in SU(2) lattice gauge\ntheory with two Dirac fermions in the adjoint representation. Depending on how\nthe extrapolation to zero fermion mass is performed, either backward running or\nan absence of running is observed at strong bare coupling. This behavior is\nconsistent with other findings which indicate that this theory has an infrared\nfixed point.",
        "positive": "A review of heavy-heavy spectroscopy: Calculations of the heavy-heavy spectrum present a good opportunity for\nprecision tests of QCD using lattice techniques. All methods make use of a\nnon-relativistic expansion of the action and its systematic improvement to\nremove lattice artefacts. There was convincing demonstration this year that\nthese methods work and that the associated perturbation theory is well-behaved.\nComparison to experimental results yields an accurate value for the lattice\nspacing, a, a key result in the determination of \\alpha_{s}, and (for the first\ntime this year) the mass of the b quark (4.7(1) GeV)."
    },
    {
        "anchor": "The running coupling from gluon and ghost propagators in the Landau\n  gauge: Yang-Mills theories with adjoint fermions: Non-Abelian gauge theories with fermions transforming in the adjoint\nrepresentation of the gauge group (AdjQCD) are a fundamental ingredient of many\nmodels that describe the physics beyond the Standard Model. Two relevant\nexamples are N=1 Supersymmetric Yang-Mills (SYM) theory and Minimal Walking\nTechnicolor, which are gauge theories coupled to one adjoint Majorana and two\nadjoint Dirac fermions, respectively. While confinement is a property of N=1\nSYM, Minimal Walking Technicolor is expected to be infrared conformal. We study\nthe propagators of ghost and gluon fields in the Landau gauge to compute the\nrunning coupling in the MiniMom scheme. We analyze several different ensembles\nof lattice Monte Carlo simulations for the SU(2) adjoint QCD with Nf=1/2, 1,\n3/2, and 2 Dirac fermions. We show how the running of the coupling changes as\nthe number of interacting fermions is increased towards the conformal window.",
        "positive": "The extraction of the axial coupling from finite volume systems: The\n  long and short of it: Due to a pion-pole contribution, the nucleon axial current matrix elements\ncan be visualized in position space as becoming delocalized as the chiral limit\nis approached, with one-third of the current at distance of order the inverse\npion mass. However, this delocalization effect will not cause calculations of\nthe axial coupling in a finite system with standard boundary conditions\n(periodic for boson fields, antiperiodic for fermions) to have large finite\nvolume effects. This is seen by calculating axial coupling using a nonstandard\ncurrent with axial quantum numbers. The matrix elements of this new current\nlacks a pion pole and is not delocalized; however, its zero-momentum matrix\nelement is identical to that of the standard axial current both for infinite\nand finite volumes."
    },
    {
        "anchor": "Adaptive Multigrid Algorithm for Lattice QCD: We present a new multigrid solver that is suitable for the Dirac operator in\nthe presence of disordered gauge fields. The key behind the success of the\nalgorithm is an adaptive projection onto the coarse grids that preserves the\nnear null space. The resulting algorithm has weak dependence on the gauge\ncoupling and exhibits very little critical slowing down in the chiral limit.\nResults are presented for the Wilson Dirac operator of the 2d U(1) Schwinger\nmodel.",
        "positive": "Phase diagram of the 2+1-dimensional Gross-Neveu model with chiral\n  imbalance: In this work, the phase diagram of the $2+1$-dimensional Gross-Neveu model is\ninvestigated with baryon chemical potential as well as chiral chemical\npotential in the mean-field approximation. We study the theory using two\nlattice discretizations, which are both based on naive fermions. An\ninhomogeneous chiral phase is observed only for one of the two discretizations.\nOur results suggest that this phase disappears in the continuum limit."
    },
    {
        "anchor": "Lattice QCD Equation of State for Nonvanishing Chemical Potential by\n  Resumming Taylor Expansion: Taylor expansion in powers of baryon chemical potential ($\\mu_B$) is an\noft-used method in lattice QCD to compute QCD thermodynamics for $\\mu_B>0$.\nBased only upon the few known lowest order Taylor coefficients, it is difficult\nto discern the range of $\\mu_B$ where such an expansion around $\\mu_B=0$ can be\ntrusted. We introduce a resummation scheme for the Taylor expansion of the QCD\nequation of state in $\\mu_B$ that is based on the $n$-point correlation\nfunctions of the conserved current ($D_n$). The method resums the contributions\nof the first $N$ correlation function $D_1,\\dots,D_N$ to the Taylor expansion\nof the QCD partition function to all orders in $\\mu_B$. We show that the\nresummed partition function is an approximation to the reweighted partition\nfunction at $\\mu_B\\ne0$. We apply the proposed approach to high-statistics\nlattice QCD calculations using 2+1 flavors of Highly Improved Staggered Quarks\nwith physical quark masses on $32^3\\times8$ lattices and for temperatures\n$T\\approx145$-176 MeV. We demonstrate that, as opposed to the Taylor expansion,\nthe resummed version not only leads to improved convergence but also reflects\nthe zeros of the resummed partition function and severity of the sign problem,\nleading to its eventual breakdown. We also provide a generalization of our\nscheme to include resummation of powers of temperature and quark masses in\naddition to $\\mu_B$, and show that the alternative expansion scheme of [S.\nBors\\'anyi et al., Phys. Rev. Lett. 126, 232001 (2021).] is a special case of\nthis generalized resummation.",
        "positive": "Cutoff Effects in O(N) Nonlinear Sigma Models: In the nonlinear O(N) sigma model at N=3 unexpected cutoff effects have been\nfound before with standard discretizations and lattice spacings. Here the\nsituation is analyzed further employing additional data for the step scaling\nfunction of the finite volume massgap at N=3,4,8 and a large N-study of the\nleading as well as next-to-leading terms in 1/N. The latter exact results are\ndemonstrated to follow Symanzik's form of the asymptotic cutoff dependence. At\nthe same time, when fuzzed with artificial statistical errors and then fitted\nlike the Monte Carlo results, a picture similar to N=3 emerges. We hence cannot\nconclude a truly anomalous cutoff dependence but only relatively large cutoff\neffects, where the logarithmic component is important. Their size shrinks at\nlarger N, but the structure remains similar. The large N results are\nparticularly interesting as we here have exact nonperturbative control over an\nasymptotically free model both in the continuum limit and on the lattice."
    },
    {
        "anchor": "Efficient vacuum state preparation for quantum simulation of strongly\n  interacting local quantum field theories: We present an efficient approach for preparing ground states in the context\nof strongly interacting local quantum field theories on quantum computers. The\napproach produces the vacuum state in a time proportional to the square-root of\nthe volume, which is a square-root improvement in speed compared to traditional\napproaches. The approach exploits a novel method for traversing the path in\nparameter space in which the resources scale linearly with a path length\nsuitably defined in parameter space. Errors due to practical limitations are\ncontrolled and do not exhibit secular growth along the path. The final accuracy\ncan be arbitrarily improved with an additive cost, which is independent of the\nvolume and grows slower than logarithmically with the overlap between the state\nproduced and the exact ground state. We expect that the method could\npotentially hold practical value not only within the realm of quantum field\ntheories but also in addressing other challenges involving long path lengths.",
        "positive": "Continuum limit of the $D$ meson, $D_s$ meson and charmonium spectrum\n  from $N_f=2+1+1$ twisted mass lattice QCD: We compute masses of $D$ meson, $D_s$ meson and charmonium states using\n$N_f=2+1+1$ Wilson twisted mass lattice QCD. All results are extrapolated to\nphysical light quark masses, physical strange and charm quark masses and to the\ncontinuum. Our analysis includes states with spin $J = 0,1,2$, parity\n$\\mathcal{P} = -,+$ and in case of charmonium also charge conjugation\n$\\mathcal{C} = -,+$. Computations are based on a large set of quark-antiquark\nmeson creation operators. We investigate and quantify all sources of systematic\nerrors, including fitting range uncertainties, finite volume effects, isospin\nbreaking effects and the choice of the fitting ansatz for the combined chiral\nand continuum extrapolation such that the resulting meson masses can be\ncompared directly and in a meaningful way to experimental results. Within\ncombined statistical and systematic errors, which are between below two per\nmille and three percent, our results agree with available experimental results\nfor most of the states. In the few cases where we observe discrepancies, we\ndiscuss possible reasons."
    },
    {
        "anchor": "What happens to the Upsilon and eta_b in the quark-gluon plasma?\n  Bottomonium spectral functions from lattice QCD: We study bottomonium spectral functions in the quark-gluon plasma in the\nUpsilon and eta_b channels, using lattice QCD simulations with two flavours of\nlight quark on highly anisotropic lattices. The bottom quark is treated with\nnonrelativistic QCD (NRQCD). In the temperature range we consider, 0.42 < T/T_c\n< 2.09, we find that the ground states survive, whereas the excited states are\nsuppressed as the temperature is increased. The position and width of the\nground states are compared to analytical effective field theory (EFT)\npredictions. Systematic uncertainties of the maximum entropy method (MEM), used\nto construct the spectral functions, are discussed in some detail.",
        "positive": "Quark Masses from Lattice QCD: In this talk I review several topics concerning the determination of quark\nmasses by means of lattice QCD simulations, with particular focus on recently\nintroduced techniques of non-perturbative renormalisation, the determination of\nheavy quark masses, and the proper quantification of the source of isospin\nbreaking effects in the light quark sector."
    },
    {
        "anchor": "A one-loop study of matching conditions for static-light flavor currents: Heavy Quark Effective Theory (HQET) computations of semi-leptonic decays,\ne.g. B -> pi l nu, require the knowledge of the parameters in the effective\ntheory for all components of the heavy-light flavor currents. So far\nnon-perturbative matching conditions have been employed only for the time\ncomponent of the axial current. Here we perform a check of matching conditions\nfor the time component of the vector current and the spatial component of the\naxial vector current up to one-loop order of perturbation theory and to lowest\norder of the 1/m-expansion. We find that the proposed observables have small\nhigher order terms in the 1/m-series and are thus excellent candidates for a\nnon-perturbative matching procedure.",
        "positive": "The asymptotic approach to the continuum of lattice QCD spectral\n  observables: We consider spectral quantities in lattice QCD and determine the asymptotic\nbehavior of their discretization errors. Wilson fermion with\nO$(a)$-improvement, (M\\\"obius) Domain wall fermion (DWF), and overlap Dirac\noperators are considered in combination with the commonly used gauge actions.\nWilson fermions and DWF with domain wall height $M_5=1+{\\rm O}(g_0^2)$ have the\nsame, approximate, form of the asymptotic cutoff effects: $ K\\,a^2\\left[\\bar\ng^2(a^{-1})\\right]^{0.760}$. A domain wall height $M_5=1.8$, as often used,\nintroduces large mass-dependent $K'(m)\\,a^2\\left[\\bar\ng^2(a^{-1})\\right]^{0.518}$ effects. Massless twisted mass fermions have the\nsame form as Wilson fermions when the Sheikholeslami-Wohlert term [1] is\nincluded. For their mass-dependent cutoff effects we have information on the\nexponents $\\hat\\Gamma_i$ of $\\bar g^2(a^{-1})$ but not for the pre-factors. For\nstaggered fermions there is only partial information on the exponents.\n  We propose that tree-level ${\\rm O}(a^2)$ improvement, which is easy to do\n[2], should be used in the future -- both for the fermion and the gauge action.\nIt improves the asymptotic behavior in all cases."
    },
    {
        "anchor": "Nucleon Structure from Lattice QCD Using a Nearly Physical Pion Mass: We report the first Lattice QCD calculation using the almost physical pion\nmass mpi=149 MeV that agrees with experiment for four fundamental isovector\nobservables characterizing the gross structure of the nucleon: the Dirac and\nPauli radii, the magnetic moment, and the quark momentum fraction. The key to\nthis success is the combination of using a nearly physical pion mass and\nexcluding the contributions of excited states. An analogous calculation of the\nnucleon axial charge governing beta decay has inconsistencies indicating a\nsource of bias at low pion masses not present for the other observables and\nyields a result that disagrees with experiment.",
        "positive": "Monopole-antimonopole condensation in the interpolating Georgi-Glashow\n  model: We study the three dimensional Georgi-Glashow model (which interpolates\nsmoothly between pure U(1) and SU(2) limits) using a constrained cooling which\npreserves 't Hooft-Polyakov monopoles. We find that the monopole-antimonopole\ncondensation gives an area law for the Wilson loops. The monopole contribution\nto the string tension is close to the Monte Carlo value in the intermediate\nregion."
    },
    {
        "anchor": "QCD thermodynamics with stabilized Wilson fermions: Stabilized Wilson fermions are a reformulation of Wilson clover fermions that\nincorporates several numerical stabilizing techniques, but also a local change\nof the fermion action - the original clover term being replaced with an\nexponentiated version of it. We intend to apply the stabilized Wilson fermions\ntoolbox to the thermodynamics of QCD, starting on the $N_f=3$ symmetric line on\nthe Columbia plot, and to compare the results with those obtained with other\nfermion discretizations.",
        "positive": "On the discretization of physical momenta in lattice QCD: The adoption of two distinct boundary conditions for two fermions species on\na finite lattice allows to deal with arbitrary relative momentum between the\ntwo particle species, in spite of the momentum quantization rule due to a\nlimited physical box size. We test the physical significance of this\ntopological momentum by checking in the continuum limit the validity of the\nexpected energy-momentum dispersion relations."
    },
    {
        "anchor": "Two-Baryon Correlation Functions in 2-flavour QCD: We present first results for two-baryon correlation functions, computed using\n$N_f=2$ flavours of O($a$) improved Wilson quarks, with the aim of explaining\npotential dibaryon bound states, specifically the H-dibaryon. In particular, we\nuse a GEVP to isolate the groundstate using two-baryon (hyperon-hyperon)\ncorrelation functions $\\big(\\langle C_{XY}(t)C_{XY}(0) \\rangle$, where\n$XY=\\Lambda\\Lambda, \\Sigma\\Sigma, N\\Xi, \\cdots\\big)$, each of which has an\noverlap with the H-dibaryon. We employ a `blocking' algorithm to handle the\nlarge number of contractions, which may easily be extended to N-baryon\ncorrelation functions. We also comment on its application to the analysis of\nsingle baryon masses ($n$, $\\Lambda$, $\\Xi$, $\\cdots$). This study is performed\non an isotropic lattice with $m_\\pi = 460$ MeV, $m_\\pi L = 4.7$ and $a = 0.063$\nfm.",
        "positive": "D_s meson spectroscopy: Preliminary results are presented for the spectrum of D_s mesons using the\n2+1 flavor Clover-Wilson configurations made available by the PACS-CS\ncollaboration. For the heavy quark, the Fermilab method is employed and we\nreport on the tuning of the charm-quark hopping parameter. As our main focus,\nwe present initial results for the spectrum of P-wave states, where previous\nresults have been mostly from quenched calculations. As a cross-check, some\ncalculations of the charmonium spectrum are also carried out."
    },
    {
        "anchor": "Structure of Abrikosov Vortices in SU(2) Lattice Gauge Theory: We calculate the electric flux and magnetic monopole current distribution in\nthe presence of a static quark-antiquark pair for SU(2) lattice gauge theory in\nthe maximal Abelian gauge. The current distribution confines the flux in a dual\nAbrikosov vortex whose core size is comparable to the flux penetration depth.\nThe observed structure is described by a dual Ginzburg-Landau model.",
        "positive": "Dynamical QCD thermodynamics with domain wall fermions: We present results from numerical simulations of full, two flavor QCD\nthermodynamics at N_t=4 with domain wall fermions. For the first time a\nnumerical simulation of the full QCD phase transition displays a low\ntemperature phase with spontaneous chiral symmetry breaking but intact flavor\nsymmetry and a high temperature phase with the full SU(2) x SU(2) chiral flavor\nsymmetry."
    },
    {
        "anchor": "Higgs mechanism near the 5d bulk phase transition: We present a non-perturbative model of Gauge-Higgs Unification. We consider a\nfive-dimensional pure SU(2) gauge theory with orbifold boundary conditions\nalong the fifth dimension, such that the symmetry is reduced to U(1) at the\nfixed points of the orbifold action. The spectrum on the four-dimensional\nboundary hyperplanes includes, apart from the U(1) gauge boson, also a complex\nscalar, interpreted as a simplified version of the Standard Model Higgs field.\nThe gauge theory is defined on a Euclidean lattice which is anisotropic in the\nextra dimension. Using the boundary Wilson Loop and the observable that\nrepresents the scalar and in the context of an expansion in fluctuations around\na Mean-Field background, we show that a) near the bulk phase transition the\nmodel tends to reduce dimensionally to a four-dimensional gauge-scalar theory,\nb) the boundary U(1) gauge symmetry breaks spontaneously due to the broken\ntranslational invariance along the fifth dimension, c) it is possible to\nconstruct renormalized trajectories on the phase diagram along which the Higgs\nmass is constant as the lattice spacing is varied, d) by taking a continuum\nlimit in the regime where the anisotropy parameter is small, it is possible to\npredict the existence of a Z' state with a mass around 1 TeV.",
        "positive": "Existence and Non-Existence of Doubly Heavy Tetraquark Bound States: In this work we investigate the existence of bound states for doubly heavy\ntetraquark systems $ \\bar{Q}\\bar{Q}'qq' $ in a full lattice-QCD computation,\nwhere heavy bottom quarks are treated in the framework of non-relativistic QCD.\nWe focus on three systems with quark content $ \\bar{b}\\bar{b}ud $, $\n\\bar{b}\\bar{b}us $ and $ \\bar{b}\\bar{c}ud $. We show evidence for the existence\nof $ \\bar{b}\\bar{b}ud $ and $ \\bar{b}\\bar{b}us $ bound states, while no binding\nappears to be present for $ \\bar{b}\\bar{c}ud $. For the bound four-quark states\nwe also discuss the importance of various creation operators and give an\nestimate of the meson-meson and diquark-antidiquark percentages."
    },
    {
        "anchor": "Absence of chiral symmetry breaking in multi-flavor strongly coupled\n  lattice gauge theories: We consider lattice gauge theories at strong coupling with gauge group\n$U(N_C)$, or $SU(N_C)$ restricted to the meson sector, and coupled to $N_F$\nflavors of fundamental representation staggered fermions. We study the\nformation of a chiral condensate by means of resummation of a hopping\nexpansion. Different classes of graphs become dominant as the parameter\n$(N_F/N_C)$ is varied. By performing graph resummation we obtain an equation\nfor determining the condensate as a function of $(N_F/N_C)$ and mass $m$. For\nvalues of $(N_F/N_C)$ below a critical value one reproduces the well-known\nresult of the existence of a non-vanishing condensate solution in the $m=0$\nlimit. Above the critical $(N_F/N_C)$ value, however, no such solution exists,\nits abrupt disappearance indicating a first order transition to a chirally\nsymmetric phase with composite (colorless) excitation spectrum.",
        "positive": "Nonperturbative excitations in overoccupied gluon plasmas: Motivated by the early-time dynamics of the quark-gluon plasma in high-energy\nheavy-ion collisions, we extract gluonic spectral functions of overoccupied\ngauge theories far from equilibrium using classical-statistical lattice\nsimulations and linear response theory. In 3+1 dimensions we find that the\nspectral function exhibits quasiparticle excitations at all momenta that are\nmostly consistent with perturbative hard-thermal loop predictions, while\npartially showing nonperturbative deviations. In contrast, the structure of\nexcitations in 2+1 dimensions is nontrivial and nonperturbative. These\nnonperturbative interactions lead to broad excitation peaks in the spectral\nfunction, demonstrating the absence of soft quasiparticles in these theories.\nThis also suggests that there may be significant nonperturbative corrections\npresent in systems with large momentum anisotropy, which are relevant to\nphenomenological applications in heavy-ion collisions."
    },
    {
        "anchor": "Mass anomalous dimension from large N twisted volume reduction: In this work we consider the SU(N) gauge theory with two Dirac fermions in\nthe adjoint representation, in the limit of large N. Taking advantage of large\nN twisted volume reduction we do this on a single site lattice, but we should\nstill get infinite-volume physics in the large N limit. We describe our\nprogress in extracting the mass anomalous dimension from the eigenvalue\ndistribution of the adjoint Dirac operator, using data for N up to 289.",
        "positive": "Universal O(N) scaling and the chiral critical line in (2+1)-flavor QCD\n  with small chemical potentials: We show that for small values of the chemical potential the curvature of the\nphase transition line can be deduced from an analysis of scaling properties of\nthe chiral condensate and its susceptibilities. We make use of a recent\nanalysis of the magnetic equation of state in (2+1)-flavor QCD where a\nconnection between the QCD parameters and the universal scaling fields could be\nestablished. The remaining dependence of the reduced temperature on the\nchemical potential can be fixed by an analysis of a mixed susceptibility,\nobtained from a derivative with respect to quark mass and chemical potential.\nWe extract this dependence which describes the curvature of the phase\ntransition line, at two values of the cut-off, $aT=1/4$ and $1/8$. We find that\ncut-off effects are small for the curvature parameter and determine the\ntransition line in the chiral limit to leading order in the light quark\nchemical potential. We obtain $T_c(\\mu_B)/T_c(0) = 1 - 0.00656(66) (\\mu_B/T)^2\n+{\\cal O}(\\mu_B^4)$."
    },
    {
        "anchor": "Leptonic and semi-leptonic B decays: We present results for the semi-leptonic and leptonic decays of B mesons.\nThese non-perturbative matrix elements are important for constraining the CKM\nmatrix. Results are presented for the pseudoscalar and vector decay constants,\nas well as flavour breaking ratios and heavy quark symmetry relations. We\nconsider the chiral and momentum dependence of the semi-leptonic form factors\nof the decay B-> pi l nu and the soft pion relation (SPR) on the lattice. These\ncalculations were performed in the quenched approximation at two values of the\ncoupling with non-perturbatively order a improved action and currents.",
        "positive": "Gell-Mann-Oakes-Renner relation for multiple chiral symmetries: As a first step towards considering a chiral perturbation theory for overlap\nfermions, we investigate whether there are any ambiguities in the expression\nfor the pion mass resulting from multiple chiral symmetries. The concern is\nthat, calculating the conserved current for Ginsparg Wilson chiral symmetries\nin the usual way, different expressions of the chiral symmetries lead to\ndifferent currents. This implies an ambiguity in the definition of the pion and\npion decay constant for all Ginsparg-Wilson expressions of the Dirac operator,\nincluding the overlap operator. We use a renormalisation group mapping\nprocedure to consider local chiral symmetry transformations for a continuum\nGinsparg-Wilson \"Dirac-operator.\" We find that this naturally leads to an\nexpression for the conserved current that differs from the standard expression\nby cut-off artefacts, but is independent of which of the Ginsparg-Wilson\nsymmetries is chosen. We recover the standard expressions for the massive Dirac\noperator, propagator, and chiral condensate. With this in place, we proceed to\ncalculate the pion mass in the mapped theory as a function of the quark mass,\nand discover a unique expression for $F_\\pi$ and $m_\\pi$, recovering the usual\nGell-Mann-Oakes-Renner relation, baring the substitution of the chiral\ncondensate with its modified value. We hypothesise that the argument can be\ncarried directly over to the lattice theory."
    },
    {
        "anchor": "Protecting local and global symmetries in simulating 1+1-D non-abelian\n  gauge theories: Efficient quantum simulation protocols for any quantum theories demand\nefficient protection protocols for its underlying symmetries. This task is\nnontrivial for gauge theories as it is involves local symmetry/invariance. For\nnon-Abelian gauge theories, protecting all the symmetries generated by a set of\nmutually non-commuting generators, is particularly difficult. In this letter, a\nglobal symmetry-protection protocol is proposed. Using the novel\nloop-string-hadron formalism of non-Abelian lattice gauge theory, we\nnumerically demonstrate that all of the local symmetries get protected even for\nlarge time by this global symmetry protection scheme. With suitable protection\nstrength, the dynamics of a (1+1)-dimensional SU(2) lattice gauge theory\nremains confined in the physical Hilbert space of the theory even in presence\nof explicit local symmetry violating terms in the Hamiltonian that may occur in\nboth analog and digital simulation schemes as an error. The whole scheme holds\nfor SU(3) gauge theory as well.",
        "positive": "Fermion Actions extracted from Lattice Super Yang-Mills Theories: We revisit 2D $\\mathcal{N}=(2,2)$ super Yang-Mills lattice formulation\n(Sugino model) to investigate its fermion action with two (Majorana) fermion\nflavors and exact chiral-$U(1)_{R}$ symmetry. We show that the reconcilement of\nchiral symmetry and absence of further species-doubling originates in the 4D\nclifford algebra structure of the action, where 2D two flavors are spuriously\ntreated as a single 4D four-spinor with four 4D gamma matrices introduced into\nkinetic and Wilson terms. This fermion construction based on the\nhigher-dimensional clifford algebra is extended to four dimensions in two\nmanners: (1) pseudo-8D sixteen-spinor treatment of 4D four flavors with eight\n8D gamma matrices, (2) pseudo-6D eight-spinor treatment of 4D two flavors with\nfive out of six 6D gamma matrices. We obtain 4D four-species and two-species\nlattice fermions with unbroken subgroup of chiral symmetry and other essential\nproperties. We discuss their relations to staggered and Wilson twisted-mass\nfermions. We also discuss their potential feedback to 4D super Yang-Mills\nlattice formulations."
    },
    {
        "anchor": "Design and optimization of a portable LQCD Monte Carlo code using\n  OpenACC: The present panorama of HPC architectures is extremely heterogeneous, ranging\nfrom traditional multi-core CPU processors, supporting a wide class of\napplications but delivering moderate computing performance, to many-core GPUs,\nexploiting aggressive data-parallelism and delivering higher performances for\nstreaming computing applications. In this scenario, code portability (and\nperformance portability) become necessary for easy maintainability of\napplications; this is very relevant in scientific computing where code changes\nare very frequent, making it tedious and prone to error to keep different code\nversions aligned. In this work we present the design and optimization of a\nstate-of-the-art production-level LQCD Monte Carlo application, using the\ndirective-based OpenACC programming model. OpenACC abstracts parallel\nprogramming to a descriptive level, relieving programmers from specifying how\ncodes should be mapped onto the target architecture. We describe the\nimplementation of a code fully written in OpenACC, and show that we are able to\ntarget several different architectures, including state-of-the-art traditional\nCPUs and GPUs, with the same code. We also measure performance, evaluating the\ncomputing efficiency of our OpenACC code on several architectures, comparing\nwith GPU-specific implementations and showing that a good level of\nperformance-portability can be reached.",
        "positive": "Charge Screening, Large-N, and the Abelian Projection Model of\n  Confinement: We point out that the abelian projection theory of quark confinement is in\nconflict with certain large-N predictions. According to both large-N and\nlattice strong-coupling arguments, the perimeter law behavior of adjoint Wilson\nloops at large scales is due to charge-screening, and is suppressed relative to\nthe area term by a factor of $1/N^2$. In the abelian projection theory,\nhowever, the perimeter law is due to the fact that $N-1$ out of $N^2-1$ adjoint\nquark degrees of freedom are (abelian) neutral and unconfined; the suppression\nfactor relative to the area law is thus only $1/N$. We study numerically the\nbehavior of Wilson loops and Polyakov lines with insertions of (abelian) charge\nprojection operators, in maximal abelian gauge. It appears from our data that\nthe forces between abelian charged, and abelian neutral adjoint quarks are not\nsignificantly different. We also show via the lattice strong-coupling expansion\nthat, at least at strong couplings, QCD flux tubes attract one another, whereas\nvortices in type II superconductors repel."
    },
    {
        "anchor": "Neutron Electric Dipole Moments with Clover Fermions: We present preliminary results for the contributions to the neutron EDM\narising from the QCD $\\theta$-term, the Weinberg three-gluon and the quark\nchromo-EDM operators from our ongoing lattice calculations using clover valence\nquarks on the MILC HISQ lattices. We use the gradient-flow technique to smooth\nthe lattices and renormalize the gluonic operators, and use the Schwinger\nsource method to incorporate the quark chromo-EDM interactions in the quark\npropagator. For the QCD $\\theta$-term and the Weinberg three-gluon operator, we\nreport results in the gradient-flow scheme from 8 ensembles at four lattice\nspacings and three pion masses, including 2 physical pion mass ensembles. For\nthe quark chromo-EDM, unrenormalized results are presented at two lattice\nspacings, $a=0.12$ and $0.09$ fm, and two pion masses, $M_\\pi = 310$ MeV and\n$220$ MeV.",
        "positive": "Ordering of Spin-$\\frac{1}{2}$ Excitations of the Nucleon in Lattice QCD: We present results for the negative parity low-lying state of the nucleon,\n$N{\\frac{1}{2}}^{-}$ (1535 MeV) ${\\rm S}_{11}$, from a variational analysis\nmethod. The analysis is performed in quenched QCD with the FLIC fermion action.\nThe principal focus of this paper is to explore the level ordering between the\nRoper (${\\rm{P}}_{11}$) and the negative parity ground (${\\rm{S}}_{11}$) states\nof the nucleon. Evidence of the physical level ordering is observed at light\nquark masses. A wide variety of smeared-smeared correlation functions are used\nto construct correlation matrices. A comprehensive correlation matrix analysis\nis performed to ensure an accurate isolation of the $N{\\frac{1}{2}}^{-}$ state."
    },
    {
        "anchor": "Quark Masses on the Lattice: Light and Heavy: I review the current status of lattice calculations of light and heavy quark\nmasses. Significant progresses, in these studies, have been allowed by the\nintroduction of improved actions and non-perturbative renormalization\ntechniques. Current determinations of light quark masses are accurate at the\nlevel of 20%, where the main source of uncertainty is represented by the\nquenching error. The determination of the bottom quark mass is accurate at the\nimpressive level of 2%. As final averages of lattice results, I quote mud(2\nGeV) = (4.5 +- 1.0) MeV, ms(2 GeV) = (110 +- 25) MeV and mb(mb) = (4.26 +-\n0.09) GeV.",
        "positive": "Gribov horizon and Gribov copies effect in lattice Coulomb gauge: Following a recent proposal by Cooper and Zwanziger we investigate via\n$SU(2)$ lattice simulations the effect on the Coulomb gauge propagators and on\nthe Gribov-Zwanziger confinement mechanism of selecting the Gribov copy with\nthe smallest non-trivial eigenvalue of the Faddeev-Popov operator, i.e.~the one\nclosest to the Gribov horizon. Although such choice of gauge drives the ghost\npropagator towards the prediction of continuum calculations, we find that it\nactually overshoots the goal. With increasing computer time, we observe that\nGribov copies with arbitrarily small eigenvalues can be found. For such a\nmethod to work one would therefore need further restrictions on the gauge\ncondition to isolate the physically relevant copies, since e.g.~the Coulomb\npotential $V_C$ defined through the Faddeev-Popov operator becomes otherwise\nphysically meaningless. Interestingly, the Coulomb potential alternatively\ndefined through temporal link correlators is only marginally affected by the\nsmallness of the eigenvalues."
    },
    {
        "anchor": "Green's Function Monte Carlo study of correlation functions in the\n  (2+1)D U(1) lattice gauge theory: A ``forward walking'' Quantum Monte Carlo (QMC) algorithm has been developed\nto calculate correlation functions for the Hamiltonian lattice formulation of\nU(1) Yang-Mills theory in (2+1) dimensions. It is shown that Wilson loops can\nbe calculated with high accuracy. Creutz ratios are used to determine the\nstring tension, which agrees with results from other approaches. Timelike\ncorrelations are used to estimate the mass gaps, which agree with series\nexpansion results in the strong coupling regime.",
        "positive": "A machine learning approach to the classification of phase transitions\n  in many flavor QCD: Normalizing flows are generative machine learning models which can\nefficiently approximate probability distributions, using only given samples of\na distribution. This architecture is used to interpolate the chiral condensate\nobtained from QCD simulations with five degenerate quark flavors in the HISQ\naction. From this a model for the probability distribution of the chiral\ncondensate as function of lattice volume, quark mass and gauge coupling is\nobtained. Using the model, first order and crossover regions can be classified\nand the boundary between these regions can be marked by a critical mass. An\nextension of this model to studies of phase transitions in QCD with variable\nnumber of flavors is expected to be possible."
    },
    {
        "anchor": "Lattice QCD study of the s-wave $\u03c0\u03c0$ scattering lengths in the I=0\n  and 2 channels: The s-wave pion-pion ($\\pi\\pi$) scattering lengths are computed below the\ninelastic threshold by the L\\\"uscher technique with pion masses ranging from\n240 MeV to 463 MeV. In the Asqtad-improved staggered fermion formulation, we\ncalculate the $\\pi\\pi$ four-point functions for the I=0 and 2 channels with\n\"moving\" wall sources without gauge fixing, and analyze them at the\nnext-to-leading order in the continuum three-flavor chiral perturbation theory.\nAt the physical pion mass, we secure the s-wave $\\pi\\pi$ scattering lengths as\n$m_\\pi a_{\\pi\\pi}^{I=0} = 0.214(4)(7)$ and $m_\\pi a_{\\pi\\pi}^{I=2} =\n-0.04430(25)(40)$ for the I=0 and 2 channels, respectively, where the first\nuncertainties are statistical and second ones are our estimates of several\nsystematic effects. Our lattice results for the s-wave $\\pi\\pi$ scattering\nlengths are in well accordance with available experimental reports and\ntheoretical forecasts at low momentum. A basic ingredient in our study for the\nI=0 case is properly incorporating disconnected diagram. These lattice\ncomputations are carried out with the MILC 2+1 flavor gauge configurations at\ntwo lattice spacings $a \\approx 0.15$ and 0.12 fm.",
        "positive": "Meson spectroscopy with derivative quark sources: We present results for masses of light mesons obtained with the variational\nmethod using an enhanced basis of interpolating field operators with different\nquark smearings. The interpolators are constructed from Jacobi-smeared quarks\nof a Gaussian type as well as from derivative quark sources obtained by a\ncovariant derivative acting on the Gaussian sources. For our analysis we use\nquenched gauge configurations with Chirally Improved quarks and the\nLuescher-Weisz gauge action on a 16^3 x 32 lattice with a = 0.148 fm. We\ndiscuss the influence of derivative sources on the overlap with excited states."
    },
    {
        "anchor": "Momentum broadening of partons on the light cone from the lattice: The jet quenching parameter describes the momentum broadening of a\nhigh-energy parton moving through the quark-gluon plasma. Following an approach\noriginally proposed by Caron-Huot, we discuss how one can extract information\non the collision kernel associated with the parton momentum broadening, from\nthe analysis of certain gauge-invariant operators in dimensionally reduced\neffective theories, and present numerical results from a lattice study.",
        "positive": "Fermion number violation and a two-dimensional Higgs model: The investigation of topological properties of the gauge field in a\ntwo-dimensional Higgs model can help in understanding anomalous fermion number\nviolation."
    },
    {
        "anchor": "Probing the tensor structure of lattice three-gluon vertex in Landau\n  gauge: In this paper we test an approximate method that is often used in lattice\nstudies of the Landau gauge three-gluon vertex. The approximation consists in\ndescribing the lattice correlator with tensor bases from the continuum theory.\nWith the help of vertex reconstruction, we show that this \"continuum\" approach\nmay lead, for general kinematics, to significant errors in vertex tensor\nrepresentations. Such errors are highly unwelcome, as they can lead to wrong\nquantitative estimates for vertex form factors and related quantities of\ninterest, like the three-gluon running coupling. As a possible solution, we\ndemonstrate numerically and analytically that there exist special kinematic\nconfigurations for which the vertex tensor structures can be described exactly\non the lattice. For these kinematics, the dimensionless tensor elements are\nequal to the continuum ones, regardless of the details of the lattice\nimplementation. We ran our simulations for an $SU(2)$ gauge theory in two and\nthree spacetime dimensions, with Wilson and $\\mathcal{O}(a^2)$ tree-level\nimproved gauge actions. Our results and conclusions can be straightforwardly\ngeneralised to higher dimensions and, with some precautions, to other lattice\ncorrelators, like the ghost-gluon, quark-gluon and four-gluon vertices.",
        "positive": "Gauge invariant 'monopoles' and color confinement mechanism: The dual Meissner effect is described and numerically observed in a\ngauge-invariant way in lattice Monte-Carlo simulations of pure SU(2) QCD. A\ngauge-invariant monopole-like quantity on the lattice is defined by a\ngauge-invariant Abelian-like field strength. The Abelian-like field strength is\nexpressed in terms of a unit-vector in color space which is constructed by a\nnon-Abelian field strength itself. It is just equal to the absolute value of\nthe corresponding non-Abelian field strength except for the sign. In this note\nwe show the theoretical background and most numerical results will be published\nin a separate report \\cite{Suzuki:2005lat052} in this conference."
    },
    {
        "anchor": "Decay constant of $B_s$ and $B^*_s$ mesons from ${\\rm N_f}=2$ lattice\n  QCD}: We report on a two-flavor lattice QCD estimate of the $B_s$ and $B^*_s$\nleptonic decays parameterized by the decay constants $f_{B_s}$ and $f_{B^*_s}$.\nIn addition to their relevance for phenomenology, their extraction has allowed\nus to investigate whether the \"step scaling in mass\" strategy is suitable with\nWlilson-Clover fermions to smoothly extrapolate quantities of the heavy-strange\nsector up to the bottom scale. From the central value of $f_{D_s}$ quoted by\nFLAG at $N_f=2$ and our ratio $\\frac{f_{B_s}}{f_{D_s}}$, we obtain\n$f_{B_s}=215(10)(2)(^{+2}_{-5})$ MeV and\n$f_{B^*_s}/f_{B_s}=1.02(2)(^{+2}_{-0})$.",
        "positive": "Topological susceptibility in 2-flavor lattice QCD with fixed topology: We determine the topological susceptibility $ \\chi_t $ in the trivial\ntopological sector generated by lattice simulations of two-flavor QCD with\noverlap Dirac fermion, on a $16^3 \\times 32$ lattice with lattice spacing\n$\\sim$ 0.12 fm, at six sea quark masses $m_q$ ranging from $m_s/6$ to $m_s$\n(where $m_s$ is the physical strange quark mass). The $ \\chi_t $ is extracted\nfrom the plateau (at large time separation) of the time-correlation function of\nthe flavor-singlet pseudoscalar meson ($\\eta'$), which arises from the finite\nsize effect due to fixed topology. In the small $m_q$ regime, our result of\n$\\chi_t$ is proportional to $m_q$ as expected from chiral effective theory.\nUsing the formula $\\chi_t=m_q\\Sigma/N_f$ by Leutwyler-Smilga, we obtain the\nchiral condensate in $N_f=2$ QCD as $\\Sigma^{\\bar{\\mathrm{MS}}}(\\mathrm{2\nGeV})=[252(5)(10) \\mathrm{MeV}]^3 $, in good agreement with our previous result\nobtained in the $\\epsilon$-regime."
    },
    {
        "anchor": "Scaling in SU(3) theory with a MCRG improved lattice action: We test various improved gauge actions which are made of linear combinations\nof Wilson loops. We observe the restoration of rotational symmetry in the\nstatic interquark potential already on coarse lattices as small as 6^3x12.\nFurthermore, we study scaling and asymptotic scaling of the string tension with\na MCRG-improved action on 12^3x24 lattices. Preliminary results show that\nscaling sets in at a ~ 0.3 fm.",
        "positive": "Critical slowing down of topological modes: We investigate the critical slowing down of the topological modes using local\nupdating algorithms in lattice 2-d CP^(N-1) models. We show that the\ntopological modes experience a critical slowing down that is much more severe\nthan the one of the quasi-Gaussian modes relevant to the magnetic\nsusceptibility, which is characterized by $\\tau_{\\rm mag} \\sim \\xi^z$ with\n$z\\approx 2$. We argue that this may be a general feature of Monte Carlo\nsimulations of lattice theories with non-trivial topological properties, such\nas QCD, as also suggested by recent Monte Carlo simulations of 4-d SU(N)\nlattice gauge theories."
    },
    {
        "anchor": "Metropolis updates for Diagrammatic Monte-Carlo algorithms from\n  Schwinger-Dyson equations: We describe a general recipe for constructing Metropolis updates for\nDiagrammatic Monte-Carlo (DiagMC) algorithms, based on the Schwinger-Dyson\nequations in quantum field theory. This approach bypasses explicit duality\ntransformations, enumeration or classification of diagrams and can be used for\nlattice quantum field theories with unknown or complicated dual representations\n(such as non-Abelian lattice gauge theories). DiagMC algorithms constructed in\nthis way can still be plagued by the sign problem, which is, however,\ncompletely different from the sign problem in conventional Monte-Carlo\nsimulations and has its origin in cancellations between diagrams with positive\nand negative weights. To test the presented approach, we apply DiagMC to\ncalculate the first 7 orders of 1/N expansion in the quartic matrix model and\nfind good agreement with analytic results, with the exception of the close\nvicinity of the critical coupling where the critical slowing down sets in.",
        "positive": "Pion loops in quenched Quantum Chromodynamics: We calculate the divergences of the generating functional of quenched Chiral\nPerturbation Theory to one loop for a generic number of flavours. The flavour\nnumber dependence of our result enlightens the mechanism of quark loop\ncancellation in the quenched effective theory for any Green function or S\nmatrix element. We also apply our results to $\\pi \\pi$ scattering and evaluate\nthe coefficient of the chiral log in the S-wave scattering lengths for the\nquenched case."
    },
    {
        "anchor": "The large $N$ limit of the topological susceptibility of Yang-Mills\n  gauge theory: We present a precise computation of the topological susceptibility\n$\\chi_{_\\mathrm{YM}}$ of SU$(N)$ Yang-Mills theory in the large $N$ limit. The\ncomputation is done on the lattice, using high-statistics Monte Carlo\nsimulations with $N=3, 4, 5, 6$ and three different lattice spacings. Two major\nimprovements make it possible to go to finer lattice spacing and larger $N$\ncompared to previous works. First, the topological charge is implemented\nthrough the gradient flow definition; and second, open boundary conditions in\nthe time direction are employed in order to avoid the freezing of the\ntopological charge. The results allow us to extrapolate the dimensionless\nquantity $t_0^2\\chi_{_\\mathrm{YM}}$ to the continuum and large $N$ limits with\nconfidence. The accuracy of the final result represents a new quality in the\nverification of large $N$ scaling.",
        "positive": "Mass spectroscopy using Borici-Creutz fermion on 2D lattice: Minimally doubled fermion proposed by Creutz and Borici is a promising chiral\nfermion formulation on lattice. In this work, we present excited state mass\nspectroscopy for the meson bound states in Gross-Neveu model using\nBorici-Creutz fermion. We also evaluate the effective fermion mass as a\nfunction of coupling constant which shows a chiral phase transition at strong\ncoupling. The lowest lying meson in 2-dimensional QED is also obtained using\nBorici-Creutz fermion."
    },
    {
        "anchor": "Glueball and gluelump spectrum in abelian projected QCD: We study glueball and gluelump spectra calculated after abelian projection in\nboth quenched and $N_f=2$ full QCD. The abelian projection is made after MA\ngauge fixing. We demonstrate that both spectra can be recovered despite the\nproblem with positivity. We suggest the interpretation of some of the gluelump\nstates in the language of the abelian projected theory.",
        "positive": "Calculation of the nucleon sigma term and strange quark content with two\n  flavors of dynamical overlap fermions: We present a calculation of the nucleon sigma term on two-flavor QCD\nconfigurations with dynamical overlap fermions. We analyse the lattice data for\nthe nucleon mass using the baryon chiral perturbation theory. Using partially\nquenched data sets, we extract the connected and disconnected contributions to\nthe nucleon sigma term separately. Chiral symmetry on the lattice simplifies\nthe determination of the disconnected contribution. We find that the strange\nquark content, which determines the neutralino dark matter reaction rate with\nnucleon through the Higgs boson exchange, is much smaller than the previous\nlattice results."
    },
    {
        "anchor": "Calorons with non-trivial holonomy on and off the lattice: We discuss recent solutions for SU(2) calorons with non-trivial holonomy at\nhigher charge, both through analytic means and using cooling, as well as\nextensive lattice studies for SU(3).",
        "positive": "Finite volume corrections to forward Compton scattering off the nucleon: We calculate the spin-averaged amplitude for doubly virtual forward Compton\nscattering off nucleons in the framework of manifestly Lorentz invariant baryon\nchiral perturbation theory at complete one-loop order $O(p^4)$. The\ncalculations are carried out both in the infinite and in a finite volume. The\nobtained results allow for a detailed estimation the finite-volume corrections\nto the amplitude which can be extracted on the lattice using the background\nfield technique."
    },
    {
        "anchor": "Ginsparg-Wilson Relation and Lattice Supersymmetry: The Ginsparg-Wilson(G-W) relation is extended for supersymmetric free\ntheories on a lattice.\n  Exact lattice supersymmetry(SUSY) can be defined without any ambiguities in\ndifference operators. The lattice action constructed by a block-spin\ntransformation is invariant under the symmetry. $U(1)_R$ symmetry on the\nlattice is also realized as one of exact symmetries.\n  For an application, the extended G-W relation is given for a two-dimensional\nmodel with chiral-multiplets. It is argued that the relation may be generalized\nfor interacting cases.",
        "positive": "Exploring twisted mass Lattice QCD with the Clover term: It has been shown that in the twisted mass formulation of Lattice QCD at\nmaximal twist large cutoff effects are generated when the quark mass becomes of\nO(a Lambda_QCD^2). In general, these effects can be suppressed in two ways:\neither by choosing the critical quark mass in an \"optimal way\", or by adding\nthe Clover term to the twisted action. We investigate the second option by\nperforming a quenched lattice QCD simulation with twisted Clover fermions and\npion masses as low as 280 MeV. We show that the Clover term is indeed efficient\nin reducing the large cutoff effects. In particular, the so-called bending\nphenomenon observed in the determination of the pion decay constant is cured in\nthis way. In addition, by using maximally twisted Clover fermions, we provide a\nnon-perturbative determination of the vector current renormalization constant\nZ_V as well as of the non-perturbatively renormalized light quark masses.\nFinally, we calculate the connected contribution to the charged-neutral\npseudoscalar meson mass splitting, finding that the introduction of the Clover\nterm in the twisted action is also beneficial, in the quenched approximation,\nin reducing cutoff effects related to the isospin symmetry breaking at finite\nlattice spacing."
    },
    {
        "anchor": "Pad\u00e9 - Z$_2$ Estimator of Determinants: We introduce the Pad\\'e--Z$_2$ (PZ) stochastic estimator for calculating\ndeterminants and determinant ratios. The estimator is applied to the\ncalculation of fermion determinants from the two ends of the Hybrid Monte Carlo\ntrajectories with pseudofermions. Our results on the $8^3 \\times 12$ lattice\nwith Wilson action show that the statistical errors from the stochastic\nestimator can be reduced by more than an order of magnitude by employing an\nunbiased variational subtraction scheme which utilizes the off-diagonal\nmatrices from the hopping expansion. Having been able to reduce the error of\nthe determinant ratios to about 20 % with a relatively small number of noise\nvectors, this may become a feasible algorithm for simulating dynamical fermions\nin full QCD. We also discuss the application to the density of states in\nHamiltonian systems.",
        "positive": "Decay amplitudes to three hadrons from finite-volume matrix elements: We derive relations between finite-volume matrix elements and infinite-volume\ndecay amplitudes, for processes with three spinless, degenerate and either\nidentical or non-identical particles in the final state. This generalizes the\nLellouch-L\\\"uscher relation for two-particle decays and provides a strategy for\nextracting three-hadron decay amplitudes using lattice QCD. Unlike for two\nparticles, even in the simplest approximation, one must solve integral\nequations to obtain the physical decay amplitude, a consequence of the\nnontrivial finite-state interactions. We first derive the result in a\nsimplified theory with three identical particles, and then present the\ngeneralizations needed to study phenomenologically relevant three-pion decays.\nThe specific processes we discuss are the CP-violating $K \\to 3\\pi$ weak decay,\nthe isospin-breaking $\\eta \\to 3\\pi$ QCD transition, and the electromagnetic\n$\\gamma^*\\to 3\\pi$ amplitudes that enter the calculation of the hadronic vacuum\npolarization contribution to muonic $g-2$."
    },
    {
        "anchor": "mc4qcd: Online Analysis Tool for Lattice QCD: mc4qcd is a web based collaboration tool for analysis of Lattice QCD data.\nLattice QCD computations consists of a large scale Markov Chain Monte Carlo.\nMultiple measurements are performed at each MC step. Our system acquires the\ndata by uploading log files, parses them for results of measurements, filters\nthe data, mines for required information by aggregating results, represents the\nresults as plots and histograms, and it further allows refining and interaction\nby fitting the results. The system computes moving averages and\nautocorrelations, builds bootstrap samples and bootstrap errors, and allows\nmodeling the data using Bayesian correlated constrained linear and non-linear\nfits. It can be scripted to allow real time visualization of results form an\nongoing computation. The system is modular and it can be adapted to automating\nthe analysis workflow of different types of MC computations.",
        "positive": "Gluon flux-tube distribution and linear confinement in baryons: We have observed the formation of gluon flux-tubes within baryons using\nlattice QCD techniques. A high-statistics approach, based on translational and\nrotational symmetries of the four-dimensional lattice, enables us to observe\ncorrelations between vacuum action density and quark positions in a completely\ngauge independent manner. This contrasts with earlier studies which used\ngauge-dependent smoothing techniques. We used 200 O(a^2) improved quenched QCD\ngauge-field configurations on a 16^3x32 lattice with a lattice spacing of 0.123\nfm. In the presence of static quarks flux tubes representing the suppression of\ngluon-field fluctuations are observed. We have analyzed 11 L-shapes and 8 T and\nY shapes of varying sizes in order to explore a variety of flux-tube\ntopologies, including the ground state. At large separations, Y-shape flux-tube\nformation is observed. T-shaped paths are observed to relax towards a Y-shaped\ntopology, whereas L-shaped paths give rise to a large potential energy. We do\nnot find any evidence for the formation of a Delta-shaped flux-tube (empty\ntriangle) distribution. However, at small quark separations, we observe an\nexpulsion of gluon-field fluctuations in the shape of a filled triangle with\nmaximal expulsion at the centre of the triangle. Having identified the precise\ngeometry of the flux distribution, we are able to perform quantitative\ncomparison between the length of the flux-tube and the associated static quark\npotential. For every source configuration considered we find a universal string\ntension, and conclude that, for large quark separations, the ground state\npotential is that which minimizes the length of the flux-tube. The flux tube\nradius of the baryonic ground state potential is found to be 0.38 \\pm 0.03 fm,\nwith vacuum fluctuations suppressed by 7.2 \\pm 0.6 %."
    },
    {
        "anchor": "$B$- and $D$-meson leptonic decay constants from four-flavor lattice QCD: We calculate the leptonic decay constants of heavy-light pseudoscalar mesons\nwith charm and bottom quarks in lattice quantum chromodynamics on four-flavor\nQCD gauge-field configurations with dynamical $u$, $d$, $s$, and $c$ quarks. We\nanalyze over twenty isospin-symmetric ensembles with six lattice spacings down\nto $a\\approx 0.03$~fm and several values of the light-quark mass down to the\nphysical value $\\frac{1}{2}(m_u+m_d)$. We employ the highly-improved\nstaggered-quark (HISQ) action for the sea and valence quarks; on the finest\nlattice spacings, discretization errors are sufficiently small that we can\ncalculate the $B$-meson decay constants with the HISQ action for the first time\ndirectly at the physical $b$-quark mass. We obtain the most precise\ndeterminations to-date of the $D$- and $B$-meson decay constants and their\nratios, $f_{D^+} = 212.7(0.6)$~MeV, $f_{D_s} = 249.9(0.4)$~MeV,\n$f_{D_s}/f_{D^+} = 1.1749(16)$, $f_{B^+} = 189.4 (1.4)$~MeV, $f_{B_s} =\n230.7(1.3)$~MeV, $f_{B_s}/f_{B^+} = 1.2180(47)$, where the errors include\nstatistical and all systematic uncertainties. Our results for the $B$-meson\ndecay constants are three times more precise than the previous best lattice-QCD\ncalculations, and bring the QCD errors in the Standard-Model predictions for\nthe rare leptonic decays $\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 3.64(11)\n\\times 10^{-9}$, $\\overline{\\mathcal{B}}(B^0 \\to \\mu^+\\mu^-) = 1.00(3) \\times\n10^{-10}$, and $\\overline{\\mathcal{B}}(B^0 \\to\n\\mu^+\\mu^-)/\\overline{\\mathcal{B}}(B_s \\to \\mu^+\\mu^-) = 0.0273(9)$ to well\nbelow other sources of uncertainty. As a byproduct of our analysis, we also\nupdate our previously published results for the light-quark-mass ratios and the\nscale-setting quantities $f_{p4s}$, $M_{p4s}$, and $R_{p4s}$. We obtain the\nmost precise lattice-QCD determination to date of the ratio $f_{K^+}/f_{\\pi^+}\n= 1.1950(^{+16}_{-23})$~MeV.",
        "positive": "Spectral density calculations in a heavy-light meson-meson system: A system of two static quarks, at fixed distances r, and two light quarks is\nstudied on an anisotropic lattice. Excitations by operators emphasizing quark\nor gluon degrees of freedom are examined. The maximum entropy method is applied\nin the spectral analysis. These simulations ultimately aim at learning about\nmechanisms of hadronic interaction."
    },
    {
        "anchor": "Non-perturbative running of quark masses in three-flavour QCD: We present our preliminary results for the computation of the\nnon-perturbative running of renormalized quark masses in $N_f = 3$ QCD, between\nthe electroweak and hadronic scales, using standard finite-size scaling\ntechniques. The computation is carried out to very high precision, using\nmassless $\\mathcal{O}(a)$-improved Wilson quarks. Following the strategy\nadopted by the ALPHA Collaboration for the running coupling, different schemes\nare used above and below a scale $\\mu_0 \\sim m_b$, which differ by using either\nthe Schr\\\"odinger Functional or Gradient Flow renormalized coupling. We discuss\nour results for the running in both regions, and the procedure to match the two\nschemes.",
        "positive": "Beyond the Standard Model Kaon Mixing with Physical Masses: We present results from a calculation of beyond the standard model (BSM) kaon\nmixing including data physical with light quark masses. We simulate $N_f=2+1$\nQCD with Iwasaki gauge and domain wall fermion action on 8 ensembles, spanning\n3 lattice spacings and pion masses from the physical value up to 430MeV. The\nratio of the BSM to standard model (SM) matrix elements are extracted from the\ncorrelation functions and renormalised using the RI-SMOM Rome-Southampton\nmethod with non-exceptional kinematics. The results at the physical point\ncontinuum limit are found by performing a simultaneous continuum chiral\nextrapolation. In this work we gain consistency with our previous results and\nachieve a reduction in both the statistical and systematic error."
    },
    {
        "anchor": "Thermodynamics of SU(3) gauge theory on anisotropic lattices: Finite temperature SU(3) gauge theory is studied on anisotropic lattices\nusing the standard plaquette gauge action. The equation of state is calculated\non $16^{3} \\times 8$, $20^{3} \\times 10$ and $24^{3} \\times 12$ lattices with\nthe anisotropy $\\xi \\equiv a_s / a_t = 2$, where $a_s$ and $a_t$ are the\nspatial and temporal lattice spacings. Unlike the case of the isotropic lattice\non which $N_t=4$ data deviate significantly from the leading scaling behavior,\nthe pressure and energy density on an anisotropic lattice are found to satisfy\nwell the leading $1/N_t^2$ scaling from our coarsest lattice, $N_t/\\xi=4$. With\nthree data points at $N_t/\\xi=4$, 5 and 6, we perform a well controlled\ncontinuum extrapolation of the equation of state. Our results in the continuum\nlimit agree with a previous result from isotropic lattices using the same\naction, but have smaller and more reliable errors.",
        "positive": "Confinement and Topological Charge in the Abelian Gauge of QCD: We study the relation between instantons and monopoles in the abelian gauge.\nFirst, we investigate the monopole in the multi-instanton solution in the\ncontinuum Yang-Mills theory using the Polyakov gauge. At a large instanton\ndensity, the monopole trajectory becomes highly complicated, which can be\nregarded as a signal of monopole condensation. Second, we study instantons and\nmonopoles in the SU(2) lattice gauge theory both in the maximally abelian (MA)\ngauge and in the Polyakov gauge. Using the $16^3 \\times 4$ lattice, we find\nmonopole dominance for instantons in the confinement phase even at finite\ntemperatures. A linear-type correlation is found between the total\nmonopole-loop length and the integral of the absolute value of the topological\ndensity (the total number of instantons and anti-instantons) in the MA gauge.\nWe conjecture that instantons enhance the monopole-loop length and promote\nmonopole condensation."
    },
    {
        "anchor": "Topological Lattice Actions for the 2d XY Model: We consider the 2d XY Model with topological lattice actions, which are\ninvariant against small deformations of the field configuration. These actions\nconstrain the angle between neighbouring spins by an upper bound, or they\nexplicitly suppress vortices (and anti-vortices). Although topological actions\ndo not have a classical limit, they still lead to the universal behaviour of\nthe Berezinskii-Kosterlitz-Thouless (BKT) phase transition - at least up to\nmoderate vortex suppression. Thus our study underscores the robustness of\nuniversality, which persists even when basic principles of classical physics\nare violated. In the massive phase, the analytically known Step Scaling\nFunction (SSF) is reproduced in numerical simulations. In the massless phase,\nthe BKT value of the critical exponent eta_c is confirmed. Hence, even though\nfor some topological actions vortices cost zero energy, they still drive the\nstandard BKT transition. In addition we identify a vortex-free transition\npoint, which deviates from the BKT behaviour.",
        "positive": "Testing the Witten-Veneziano Formula on the Lattice: In this proceeding contribution we report on a test of the famous\nWitten-Veneziano formula using lattice techniques. We perform dedicated\nquenched simulations and apply the spectral projector method to determine the\ntopological susceptibility in pure Yang-Mills theory. In order to compute the\nrelevant meson masses and the flavor singlet decay constant we employ lattice\nQCD with $N_f=2+1+1$ dynamical Wilson twisted mass fermions. Taking the\ncontinuum and the $SU(2)$ chiral limits we find good agreement within\nuncertainties for both sides of the formula."
    },
    {
        "anchor": "Improved lattice computation of proton decay matrix elements: We present an improved result of lattice computation of the proton decay\nmatrix elements in $N_f=2+1$ QCD. In this study, the significant improvement of\nstatistical accuracy by adopting the error reduction technique of\nAll-mode-averaging, is achieved for relevant form factor to proton (and also\nneutron) decay on the gauge ensemble of $N_f=2+1$ domain-wall fermions in\n$m_\\pi=0.34$--0.69 GeV on 2.7~fm$^3$ lattice as used in our previous work\n\\cite{Aoki:2013yxa}. We improve total accuracy of matrix elements to 10--15\\%\nfrom 30--40\\% for $p\\rightarrow\\pi e^+$ or from 20--40\\% for $p\\rightarrow K\n\\bar\\nu$. The accuracy of the low energy constants $\\alpha$ and $\\beta$ in the\nleading-order baryon chiral perturbation theory (BChPT) of proton decay are\nalso improved. The relevant form factors of $p\\rightarrow \\pi$ estimated\nthrough the \"direct\" lattice calculation from three-point function appear to be\n1.4 times smaller than those from the \"indirect\" method using BChPT with\n$\\alpha$ and $\\beta$. It turns out that the utilization of our result will\nprovide a factor 2--3 larger proton partial lifetime than that obtained using\nBChPT. We also discuss the use of these parameters in a dark matter model.",
        "positive": "Order a improved renormalization constants: We present non-perturbative results for the constants needed for on-shell\n$O(a)$ improvement of bilinear operators composed of Wilson fermions. We work\nat $\\beta=6.0$ and 6.2 in the quenched approximation. The calculation is done\nby imposing axial and vector Ward identities on correlators similar to those\nused in standard hadron mass calculations. A crucial feature of the calculation\nis the use of non-degenerate quarks. We also obtain results for the constants\nneeded for off-shell $O(a)$ improvement of bilinears, and for the scale and\nscheme independent renormalization constants, (Z_A), (Z_V) and (Z_S/Z_P).\nSeveral of the constants are determined using a variety of different Ward\nidentities, and we compare their relative efficacies. In this way, we find a\nmethod for calculating $c_V$ that gives smaller errors than that used\npreviously. Wherever possible, we compare our results with those of the ALPHA\ncollaboration (who use the Schr\\\"odinger functional) and with 1-loop\ntadpole-improved perturbation theory."
    },
    {
        "anchor": "Bayesian study of relativistic open and hidden charm in anisotropic\n  lattice QCD: We present the first combined study of correlators and spectral properties of\ncharmonium and open-charm-mesons at finite temperature using a fully\nrelativistic lattice QCD approach. The QCD medium is captured by second\ngeneration anisotropic 24^3xN_t lattices from the FASTSUM collaboration,\nincluding 2+1 flavors of clover discretized quarks with m_pi~380 MeV. Two\nBayesian methods are deployed to reconstruct the spectral functions, the recent\nBR method as well as the Maximum Entropy Method with Fourier basis. We take\nparticular care to disentangle genuine in-medium effects from method artifacts\nwith the help of the reconstructed correlator. Consistent with the direct\ninspection of correlators, we observe no significant in-medium modification for\nJ/Psi and eta_c around the crossover, while the chi_c states on the other hand\nshow clear changes around the transition. At the highest temperature, T=352\nMeV, J/Psi and eta_c also exhibit discernible changes compared to the vacuum.\nFor D mesons around $T_c$, no significant modifications are observed, but we\nfind clear indications that no bound state survives at the highest temperature\nof T=352 MeV. Above T_c we discover a significant difference between D and D*\nmesons, the latter being much more strongly affected by the medium.",
        "positive": "High precision study of B*B pi coupling in unquenched QCD: The B* B pi coupling is a fundamental parameter of chiral effective\nLagrangian with heavy-light mesons and can constrain the B->pi l nu form factor\nin the soft pion limit which will be useful for precise determination of |Vub|.\nWe compute the B* B pi coupling with the static heavy quark and the\nO(a)-improved Wilson light quark. Simulations are carried out with n_f=2\nunquenched 12^3x24 lattices at beta=1.80 generated by CP-PACS collaboration.\nFollowing the quenched study by Negishi et al., we employ the all-to-all\npropagator with 200 low eigenmodes as well as HYP smeared link to improve the\nstatistical accuracy."
    },
    {
        "anchor": "Relativistic Heavy Quarks on the Lattice: Lattice QCD should allow quantitative predictions for the heavy quark physics\nfrom first principles. Up to now, however, most approaches have based on the\nnonrelativistic effective theory, with which the continuum limit can not be\ntaken in principle. In this paper we investigate feasibility of relativistic\napproaches to the heavy quark physics in lattice QCD. We first examine validity\nof the idea that the use of the anisotropic lattice could be advantageous to\ncontrol the $m_Q a$ corrections. Our perturbative calculation, however, reveals\nthat this is not true. We instead propose a new relativistic approach to handle\nheavy quarks on the isotropic lattice. We explain how power corrections of $m_Q\na$ can be avoided and remaining uncertainties are reduced to be of order\n$(a\\Lambda_{QCD})^2$.",
        "positive": "First study of $B \\to \u03c0$ semileptonic decay form factors using NRQCD: We present a quenched calculation of the form factors of the semileptonic\nweak decay $B \\to \\pi l \\bar{\\nu}$ with $O(1/m_Q)$ NRQCD heavy quark and Wilson\nlight quark on a $16^3 \\times 32$ lattice at $\\beta=5.8$. The form factors are\nevaluated at six heavy quark masses, in the range of $m_Q \\sim 1.5-8$ GeV.\n$1/m_Q$ dependence of matrix elements are investigated and compared with HQET\npredictions. We observe clear signal for the form factors near $q^2_{max}$,\neven at the $b$-quark mass range. $f^0(q^2_{max})$ is compared with\n$f_B/f_{\\pi}$ based on the soft pion theorem and significant difference is\nobserved."
    },
    {
        "anchor": "Real--time dynamics of a hot Yang-Mills theory: a numerical analysis: We discuss recent results obtained from simulations of high temperature,\nclassical, real time dynamics of SU(2) Yang-Mills theory at temperatures of the\norder of the electroweak scale. Measurements of gauge covariant and gauge\ninvariant autocorrelations of the fields indicate that the ASY-Bodecker\nscenario is irrelevant at these temperatures.",
        "positive": "Lattice QCD at Finite Temperature and Density: A general introduction into the subject aimed at a general theoretical\nphysics audience. We introduce the sign problem posed by finite density lattice\nQCD, and we discuss the main methods proposed to circumvent it, with emphasis\non the imaginary chemical potential approach. The interrelation between the\nTaylor expansion and the analytic continuation from imaginary chemical\npotential is discussed in detail. The main applications to the calculation of\nthe critical line, and to the thermodynamics of the hot and the hadronic phase\nare reviewed."
    },
    {
        "anchor": "Spin and Gauge Systems on Spherical Lattices: We present results for 2D and 4D systems on lattices with topology homotopic\nto the surface of a (hyper) sphere $S^2$ or $S^4$. Finite size scaling is\nstudied in situations with phase transitions of first and second order type.\nThe Ising and Potts models exhibit the expected behaviour; for the 4D pure\ngauge $U(1)$ theory we find consistent scaling indicative of a second order\nphase transition with critical exponent $\\nu\\simeq 0.36(1)$.",
        "positive": "The critical end point of QCD: We investigate the critical end point of QCD with two flavours of light\ndynamical quarks at finite lattice cutoff a=1/4T using a Taylor expansion of\nthe baryon number susceptibility. We find a strong volume dependence of the\nposition of the critical end point. In the large volume limit we obtain T^E/T_c\n\\~ 0.95 and mu_B^E/T^E ~ 1.1, where T_c is the cross over temperature at zero\nchemical potential, and T^E and mu_B^E are the temperature and the baryon\nchemical potential at the critical end point. The small value of mu_B^E places\nit in the range of observability in energy scans at the RHIC."
    },
    {
        "anchor": "Clear Evidence of a Continuum Theory of 4D Euclidean Simplicial Quantum\n  Gravity: Four-dimensional (4D) simplicial quantum gravity coupled to both scalar\nfields (N_X) and gauge fields (N_A) has been studied using Monte-Carlo\nsimulations. The matter dependence of the string susceptibility exponent\ngamma^{(4)} is estimated. Furthermore, we compare our numerical results with\nBackground-Metric-Independent (BMI) formulation conjectured to describe the\nquantum field theory of gravity in 4D. The numerical results suggest that the\n4D simplicial quantum gravity is related to the conformal gravity in 4D.\nTherefore, we propose a phase structure in detail with adding both scalar and\ngauge fields and discuss the possibility and the property of a continuum theory\nof 4D Euclidean simplicial quantum gravity.",
        "positive": "Chiral symmetry on the lattice: As a non-perturbative and gauge invariant regularization the lattice provides\na tool for deeper understanding of the celebrated Yang-Mills theory, QCD and\nchiral gauge theories. For illustration, I discuss some analytic developments\non the lattice related to chiral symmetry, chiral fermions and improvement\nprograms. Chiral symmetry on the lattice has an amazing history, and it might\ninfluence our perception of a symmetry beyond this example."
    },
    {
        "anchor": "A novel Bayesian approach to spectral function reconstruction: We present a novel approach to the inference of spectral functions from\nEuclidean time correlator data that makes close contact with modern Bayesian\nconcepts. Our method differs significantly from the maximum entropy method\n(MEM). A new set of axioms is postulated for the prior probability, leading to\nan improved expression, which is devoid of the asymptotically flat directions\npresent in the Shanon-Jaynes entropy. Hyperparameters are integrated out\nexplicitly, liberating us from the Gaussian approximations underlying the\nevidence approach of the MEM. We present a realistic test of our method in the\ncontext of the non-perturbative extraction of the heavy quark potential. Based\non hard-thermal-loop correlator mock data, we establish firm requirements in\nthe number of data points and their accuracy for a successful extraction of the\npotential from lattice QCD. An improved potential estimation from previously\ninvestigated quenched lattice QCD correlators is provided.",
        "positive": "The $\\mathbb{C}$P(2) Model at Non-Zero Chemical Potential: Recently the simulation of quantum field theories using man-made physical\nsystems has become realistic. In this publication we present numerical results\nwhich support the use of quantum simulation experiments to study quantum field\ntheories at non-zero chemical potential. We have numerically simulated the\n(1+1)-d $\\mathbb{C}$P(2) model, which shares several interesting features with\nQCD, namely asymptotic freedom, a dynamically generated mass gap and\ntopological sectors, via dimensional reduction of a (2+1)-d microscopic theory\nof SU(3) quantum spins. Numerical results for the particle number density as a\nfunction of chemical potential are presented."
    },
    {
        "anchor": "Gauge invariant investigation of the nature of Confinement: We observe a strong correlation between the decrease in the number of action\ndensity peaks in SU(2) Yang-Mills configurations with cooling and that of the\nstring tension. The nature and distribution of these peaks is investigated. The\nrelationship with monopole currents after the abelian projection is also\nconsidered.",
        "positive": "Dynamical Triangulation with Fluctuating Topology: We consider a dynamical triangulation model of euclidean quantum gravity\nwhere the topology is not fixed. This model is equivalent to a tensor\ngeneralization of the matrix model of two dimensional quantum gravity. A set of\nmoves is given that allows Monte Carlo simulation of this model. Some\npreliminary results are presented for the case of four dimensions."
    },
    {
        "anchor": "Charm (and bottom) baryons and charmonium excitations from the lattice: This report discusses some recent investigations of the heavy hadron spectra\nusing lattice QCD. The first half addresses multiple precision determinations\nof the masses of charm (and bottom) baryons. Recent lattice results in the\ntetraquark and the dibaryon sectors are also presented. The second half focuses\non new exploratory studies of the excited charmonium spectra in the vector and\nscalar channels. Along the way, lattice results are compared with the\nexperimental results, wherever they are available.",
        "positive": "Staggered fermion matrix elements using smeared operators: We investigate the use of two kinds of staggered fermion operators, smeared\nand unsmeared. The smeared operators extend over a $4^4$ hypercube, and tend to\nhave smaller perturbative corrections than the corresponding unsmeared\noperators. We use these operators to calculate kaon weak matrix elements on\nquenched ensembles at $\\beta=6.0$, 6.2 and 6.4. Extrapolating to the continuum\nlimit, we find $B_K(NDR, 2 GeV)= 0.62\\pm 0.02(stat)\\pm 0.02(syst)$. The\nsystematic error is dominated by the uncertainty in the matching between\nlattice and continuum operators due to the truncation of perturbation theory at\none-loop. We do not include any estimate of the errors due to quenching or to\nthe use of degenerate $s$ and $d$ quarks. For the $\\Delta I = {3/2}$\nelectromagnetic penguin operators we find $B_7^{(3/2)} = 0.62\\pm 0.03\\pm 0.06$\nand $B_8^{(3/2)} = 0.77\\pm 0.04\\pm 0.04$. We also use the ratio of unsmeared to\nsmeared operators to make a partially non-perturbative estimate of the\nrenormalization of the quark mass for staggered fermions. We find that tadpole\nimproved perturbation theory works well if the coupling is chosen to be\n$\\alpha_\\MSbar(q^*=1/a)$."
    },
    {
        "anchor": "Chiral perturbation theory for partially quenched twisted mass lattice\n  QCD: Partially quenched Quantum Chromodynamics with Wilson fermions on a lattice\nis considered in the framework of chiral perturbation theory. Two degenerate\nquark flavours are associated with a chirally twisted mass term. The pion\nmasses and decay constants are calculated in next-to-leading order including\nterms linear in the lattice spacing $a$.",
        "positive": "Dirac-mode expansion of quark number density and its implications of the\n  confinement-deconfinement transition: We investigate the quark number density at finite imaginary chemical\npotential by using the Dirac-mode expansion. In the large quark mass region, it\nis found that the quark number density can be expressed by the Polyakov loop\nand its conjugate in all order of the large quark mass expansion. Then, there\nare no specific Dirac-modes which dominantly contribute to the quark number\ndensity. In comparison, the small quark mass region is explored by using the\nquenched lattice QCD simulation. We found that the absolute value of the quark\nnumber density strongly depends on the low-lying Dirac-modes, but its sign does\nnot. This means that the existence of the Roberge-Weiss transition which is\ncharacterized by the singular behavior of the quark number density is not\nsensitive to low-lying Dirac-modes. This property enables us to discuss the\nconfinement-deconfinement transition from the behavior of the quark number\ndensity via the quark number holonomy."
    },
    {
        "anchor": "Quenched Light Hadron Spectroscopy: Comparing the Wilson and\n  O(a)-Improved Fermion Actions: We have studied the light hadron spectrum and decay constants for quenched\nQCD at beta=6.2 on a 24^3x48 lattice. We compare the results obtained using a\nnearest-neighbour O(a)-improved (\"clover\") fermion action with those obtained\nusing the standard Wilson fermion action on the same gauge configurations. For\npseudoscalar meson masses in the range 330-800 MeV, we find no significant\ndifference between the results for the two actions. The scales obtained from\nthe string tension and mesonic sector are consistent, but higher than those\nderived from baryon masses. The ratio of the pseudoscalar decay constant to the\nvector meson mass is roughly independent of quark mass as observed\nexperimentally.",
        "positive": "Lattice Renormalization of Quantum Simulations: With advances in quantum computing, new opportunities arise to tackle\nchallenging calculations in quantum field theory. We show that trotterized\ntime-evolution operators can be related by analytic continuation to the\nEuclidean transfer matrix on an anisotropic lattice. In turn, trotterization\nentails renormalization of the temporal and spatial lattice spacings. Based on\nthe tools of Euclidean lattice field theory, we propose two schemes to\ndetermine Minkowski lattice spacings, using Euclidean data and thereby\novercoming the demands on quantum resources for scale setting. In addition, we\nadvocate using a fixed-anisotropy approach to the continuum to reduce both\ncircuit depth and number of independent simulations. We demonstrate these\nmethods with Qiskit noiseless simulators for a $2+1$D discrete non-Abelian\n$D_4$ gauge theory with two spatial plaquettes."
    },
    {
        "anchor": "Critical point phase transition for finite temperature 3-flavor QCD with\n  non-perturbatively O($a$) improved Wilson fermions at $N_{\\rm t}=10$: We study the finite temperature phase structure for three-flavor QCD with a\nfocus on locating the critical point which separates crossover and first order\nphase transition region in the chiral regime of the Columbia plot. In this\nstudy, we employ the Iwasaki gauge action and the non-perturvatively O($a$)\nimproved Wilson-Clover fermion action. We discuss the finite size scaling\nanalysis including the mixing of magnetization-like and energy-like\nobservables. We carry out the continuum extrapolation of the critical point\nusing newly generated data at $N_{\\rm t}=8$, $10$ and estimate the upper bound\nof the critical pseudo-scalar meson mass $m_{\\rm PS,E} \\lesssim 170 {\\rm MeV}$\nand the critical temperature $T_{\\rm E}=134(3){\\rm MeV}$. Our estimate of the\nupper bound is derived from the existence of the critical point as an edge of\nthe 1st order phase transition while that of the staggered-type fermions is\nbased on its absence.",
        "positive": "Structure Functions on the lattice: We report on a lattice computation of the second moment of the pion matrix\nelement of the twist-2 non-singlet operator corresponding to the average\nmomentum of parton densities. We apply a fully non-perturbatively evaluated\nrunning renormalization constant as well as a careful extrapolation of our\nresults to the continuum limit. Thus the only limitation of our final result is\nthe quenched approximation."
    },
    {
        "anchor": "Blocking from continuum and monopoles in gluodynamics: We review the method of blocking of topological defects from continuum used\nas a non--perturbative tool to construct effective actions for these defects.\nThe actions are formulated in the continuum limit while the couplings of these\nactions can be derived from simple observables calculated numerically on\nlattices with a finite lattice spacing. We demonstrate the success of the\nmethod in deriving the effective actions for Abelian monopoles in the pure\nSU(2) gauge models in an Abelian gauge. In particular, we discuss the\ngluodynamics in three and four space--time dimensions at zero and non--zero\ntemperatures. Besides the action the quantities of our interest are the\nmonopole density, the magnetic Debye mass and the monopole condensate.",
        "positive": "Use of even Grassmann variables to construct effective actions for\n  mesons: A quadratic action in even Grassmann variables with the quantum numbers of\nthe pions has been studied. It includes the $\\sigma$-field in order to be\ninvariant under SU(2)_L times SU(2)_R transformations over the quarks. This\naction exhibits the Goldstone phenomenon reducing its symmetry to the O(3)\nisospin invariance. The model has been investigated in the\nStratonovitch-Hubbard representation, in which form it is reminiscent of the\nGell-Mann-Levy model. By the saddle point method a renormalizable expansion in\ninverse powers of the index of nilpotency of the mesonic fields (which is 24),\nis generated. The way it might be used in a new perturbative approach to QCD is\noutlined."
    },
    {
        "anchor": "Unquenching effects on the coefficients of the L\u00fcscher-Weisz action: The effects of unquenching on the perturbative improvement coefficients in\nthe Symanzik action are computed within the framework of L\\\"uscher-Weisz\non-shell improvement. We find that the effects of quark loops are surprisingly\nlarge, and their omission may well explain the scaling violations observed in\nsome unquenched studies.",
        "positive": "New lattice approaches to the $\u0394I=1/2$ rule: Lattice QCD should allow a derivation of the $\\Delta I=1/2$ rule from first\nprinciples, but numerical calculations to date have been plagued by a variety\nof problems. After a brief review of these problems, we present several new\nmethods for calculating $K\\to\\pi\\pi$ amplitudes. These are designed for Wilson\nfermions, though they can be used also with staggered fermions. They all\ninvolve a non-perturbative determination of matching coefficients. We show how\nproblems of operator mixing can be greatly reduced by using point-split\nhadronic currents, and how CP violating parts of the $K\\to\\pi\\pi$ amplitudes\ncan be calculated by introducing a fake top quark. Many of the methods can also\nbe applied to the calculation of two body non-leptonic B-meson decays."
    },
    {
        "anchor": "Real-time gauge theory simulations from stochastic quantization with\n  optimized updating: We investigate simulations for gauge theories on a Minkowskian space-time\nlattice. We employ stochastic quantization with optimized updating using\nstochastic reweighting or gauge fixing, respectively. These procedures do not\naffect the underlying theory but strongly improve the stability properties of\nthe stochastic dynamics, such that simulations on larger real-time lattices can\nbe performed.",
        "positive": "Exotic hadronic states and all-to-all quark propagators: We discuss methods to obtain accurate hadronic spectra with propagating\nquarks. Comparing the determination of masses for spin-exotic hybrid mesons\nwith glueball mass determinations, we conclude that quark propagators from all\nsites to all other sites would enable great improvement in the errors. Such\npropagators are achievable by using stochastic estimators. We discuss previous\nattempts and present our method for maximal variance reduction. This is a very\npromising technique and we illustrate it by obtaining the spectrum of ground\nstate and excited B mesons in the limit where the $b$ quark is static."
    },
    {
        "anchor": "Improved Error Estimate for the Valence Approximation: We construct a systematic mean-field-improved coupling constant and quark\nloop expansion for corrections to the valence (quenched) approximation to\nvacuum expectation values in the lattice formulation of QCD. Terms in the\nexpansion are evaluated by a combination of weak coupling perturbation theory\nand a Monte Carlo algorithm.",
        "positive": "Unquenched simulations of four-nucleon interactions: Exploratory simulations of four-nucleon interactions are performed taking\ninto account the dynamical effects of internal nucleon loops. The four-nucleon\ninteractions in the isoscalar and isovector channels are described by Yukawa\ninteractions with auxiliary scalar fields. The nucleon mass and the average\nfield lengths of the scalar fields are determined as a function of nucleon\nhopping parameter and Yukawa coupling strengths. There are no problems with\n\"exceptional configurations\" at strong couplings which make quenched\nsimulations unreliable."
    },
    {
        "anchor": "Numerical investigations of the Schwinger model and selected quantum\n  spin models: Numerical investigations of the XY model, the Heisenberg model and the J-J'\nHeisenberg model are conducted, using the exact diagonalisation, the numerical\nrenormalisation and the density matrix renormalisation group approach. The\nlow-lying energy levels are obtained and finite size scaling is performed to\nestimate the bulk limit values. The results are found to be consistent with the\nexact values. The DMRG results are found to be most promising.\n  The Schwinger model is also studied using the exact diagonalisation and the\nstrong coupling expansion. The massless, the massive model and the model with a\nbackground electric field are explored. Ground state energy, scalar and vector\nparticle masses and order parameters are examined. The achieved values are\nobserved to be consistent with previous results and theoretical predictions.\nPath to the future studies is outlined.",
        "positive": "$\u039b_c-N$ interaction from lattice QCD: We investigate the s-wave $\\Lambda_c-N$ interaction for spin singlet\nsystems($^1S_0$) using the HAL QCD method. In our lattice QCD simulations, we\nemploy gauge configurations generated by the PACS-CS Collaboration at $a =\n0.0907(13)$ fm on a $32^3 \\times 64$ lattice ($La = 2.902(42)$ fm). We employ\ntwo ensembles, one at $m_\\pi = 700(1)$ MeV and the other at $m_\\pi = 570(1)$\nMeV to study the quark mass dependence of the $\\Lambda_c-N$ interactions. We\ncalculate a $^1S_0$ central potential not only for the $\\Lambda_c-N$ system but\nalso for $\\Lambda-N$ system to understand the role of heavy charm quarks in\n$\\Lambda_c-N$ system. We find repulsion at short distance and attraction at\nmid-range for both the $\\Lambda_c-N$ and the $\\Lambda-N$ potentials. The short\nrange repulsion of the $\\Lambda_c-N$ potential is smaller than that of the\n$\\Lambda-N$ potential, and the attraction of the $\\Lambda_c-N$ potential is\nsmall compared with the $\\Lambda-N$ potential. The phase shift and scattering\nlength calculated with these potentials show that there exist no bound state\nfor both the $\\Lambda_c-N$ and $\\Lambda-N$ systems for $m_{\\pi} > 570$ MeV."
    },
    {
        "anchor": "Exotic Tetraquark states with two $\\bar{b}$-quarks and $J^P=0^+$ and\n  $1^+$ $B_s$ states in a nonperturbatively-tuned Lattice NRQCD setup: We use $n_f=2+1$ Wilson-clover gauge-field ensembles from the CLS consortium\nin a Lattice NRQCD setup to predict the binding energy of a $I(J^P)=0(1^+)$\n$ud\\bar{b}\\bar{b}$ tetraquark and a $\\frac{1}{2}(1^+)$ $\\ell s\\bar{b}\\bar{b}$\ntetraquark. We determine the binding energies with respect to the relevant\n$BB^*$ and $B_sB^*$ thresholds respectively to be $112.0(13.2)$ MeV for the\n$ud\\bar{b}\\bar{b}$, and $46.4(12.3)$ MeV for the $\\ell s\\bar{b}\\bar{b}$. We\nalso determine the ground-state $J^P=0^+$ $B_{s0}^*$ and $1^+$ $B_{s1}$ mesons\nto lie $75.4(14.0)$ and $78.7(13.9)$ MeV below the $BK$ and $B^*K$ thresholds\nrespectively. Our errors are entirely dominated by systematics due to\ndiscretisation effects. To achieve these measurements, we performed a neural\nnetwork based nonperturbative tuning of the Lattice NRQCD Hamiltonian's\nparameters against the basic bottomonium spectrum. For all lattice spacings\nconsidered we can reproduce the continuum splittings of low-lying bottomonia.\nIt is worth remarking that our nonperturbative tuning parameters deviate from 1\nby significant amounts, particularly the term $c_2$.",
        "positive": "The $N_f= 2$ chiral phase transition from imaginary chemical potential\n  with Wilson Fermions: The order of the thermal transition in the chiral limit of QCD with two\ndynamical flavours of quarks is a long-standing issue. Still, it is not\ndefinitely known whether the transition is of first or second order in the\ncontinuum limit. Which of the two scenarios is realized has important\nimplications for the QCD phase diagram and the existence of a critical endpoint\nat finite densities. Settling this issue by simulating at successively\ndecreased pion mass was not conclusive yet. Recently, an alternative approach\nwas proposed, extrapolating the first order phase transition found at imaginary\nchemical potential to zero chemical potential with known exponents, which are\ninduced by the Roberge-Weiss symmetry. For staggered fermions on $N_t=4$\nlattices, this results in a first order transition in the chiral limit. Here we\nreport of $N_t=4$ simulations with Wilson fermions, where the first order\nregion is found to be large."
    },
    {
        "anchor": "A Lattice Chiral Theory with Multifermion Couplings: Analyzing an $SU_L(2)\\otimes U_R(1)$ chiral theory with multifermion\ncouplings on a lattice, we find a possible region in the phase space of\nmultifermion couplings, where no spontaneous symmetry breaking occurs, doublers\nare decoupled as massive Dirac fermions consistently with the $SU_L(2)\\otimes\nU_R(1)$ chiral symmetry, the ``spectator'' fermion $\\psi_R(x)$ is free mode,\nwhereas the normal mode of $\\psi^i_L(x)$ is plausibly speculated to be chiral\nin the continuum limit. This is not in agreement with the general belief of the\ndefinite failure of theories so constructed.",
        "positive": "The spectrum and mass anomalous dimension of SU(2) adjoint QCD with two\n  Dirac flavours: In this work we present the results of our investigation of \\su{2} gauge\ntheory with two Dirac fermions in the adjoint representation (aQCD2), which\nbelongs to the class of strongly interacting gauge theories that are of basic\ninterest for extensions of the Standard Model. We have done numerical lattice\nsimulations of this theory at two different values of the gauge coupling and\nseveral fermion masses. Our results include the particle spectrum and the mass\nanomalous dimension. The spectrum contains new exotic fermion-gluon states and\nflavour-singlet mesons. The mass anomalous dimension is determined from the\nscaling of the masses and the mode number. The remnant dependence of the\nuniversal mass ratios and mass anomalous dimension on the gauge coupling\nindicates the relevance of scaling corrections, such that earlier estimations\nfor the universal fixed point value of the mass anomalous dimension are\nincomplete without their inclusion."
    },
    {
        "anchor": "Overlap fermions on GPUs: We report on our efforts to implement overlap fermions on NVIDIA GPUs using\nCUDA, commenting on the algorithms used, implemetation details, and the\nperformance of our code.",
        "positive": "Bulk Thermodynamics of SU(N) Lattice Gauge Theories at Large-N: We present a study of bulk thermodynamical quantities in the deconfined phase\nof pure lattice SU(N) gauge theories. We find that the deficit in pressure and\nentropy with respect to their free-gas values, for N=4,8, is remarkably close\nto that of SU(3). Th is suggests that understanding the strongly interacting\nnature of the deconfined phase, which is crucial for RHIC physics, can be done\nat large N. There, different analytical approaches simplify or become soluble,\nand one can check their predictions and point to their important ingredients."
    },
    {
        "anchor": "Critical Behaviour in the Dense Planar NJL Model: We present results of a Monte Carlo simulation of a 2+1 dimensional Nambu -\nJona-Lasinio model including diquark source terms. A diquark condensate <qq> is\nmeasured as a function of source strength j. In the vacuum phase <qq> vanishes\nlinearly with j as expected, but simulations in a region with non-zero baryon\ndensity suggest a power-law scaling and hence a critical system for all mu >\nmu_c. There is no diquark condensation signalling superfluidity. Comparisons\nare drawn with known results in two dimensional theories, and with the\npseudogap phase in cuprate superconductors. We also measure the dispersion\nrelation E(k) for fermionic excitations, and find results consistent with a\nsharp Fermi surface. Any superfluid gap Delta is constrained to be much less\nthan the constituent quark mass scale Sigma_0.",
        "positive": "Lattice QCD on upcoming Arm architectures: Recently Arm introduced a new instruction set called Scalable Vector\nExtension (SVE), which supports vector lengths up to 2048 bits. While SVE\nhardware will not be generally available until about 2021, we believe that\nfuture SVE-based architectures will have great potential for Lattice QCD. In\nthis contribution we discuss key aspects of SVE and describe how we implemented\nSVE in the Grid Lattice QCD framework."
    },
    {
        "anchor": "Hadron-Hadron Interactions from $N_f=2+1+1$ Lattice QCD: The\n  $\u03c1$-resonance: We present an investigation of the Rho-meson from Nf=2+1+1 flavour lattice\nQCD. The calculation is performed based on gauge configuration ensembles\nproduced by the ETM collaboration with three lattice spacing values and pion\nmasses ranging from 230 MeV to 500 MeV. Applying the L\\\"uscher method phase\nshift curves are determined for all ensembles separately. Assuming a\nBreit-Wigner form, the Rho-meson mass and width are determined by a fit to\nthese phase shift curves. Mass and width combined are then extrapolated to the\nchiral limit, while lattice artefacts are not detectable within our statistical\nuncertainties. For the Rho-meson mass extrapolated to the physical point we\nfind good agreement with experiment. The corresponding decay width differs by\nabout two standard deviations from the experimental value.",
        "positive": "Towards a non-perturbative measurement of the heavy quark momentum\n  diffusion coefficient: We report on a lattice investigation of heavy quark diffusion within pure\nSU(3) plasma above the deconfinement transition, with the quarks treated to\nleading order in the heavy mass expansion. Using a multilevel algorithm,\nseveral volumes and lattice spacings, as well as tree-level improvement and\nperturbative renormalization, we measure the relevant \"colour-electric\"\nEuclidean correlator, finding that it clearly exceeds its perturbative\ncounterpart. Even without analytic continuation, this suggests that at\ntemperatures just above the critical one, non-perturbative interactions felt by\nthe heavy quarks are stronger than within the weak-coupling expansion. After\nintroducing rough modelling of the spectral shape, diffusion coefficients down\nto D ~ 0.5/T appear possible."
    },
    {
        "anchor": "A study of large field configurations in MC simulations: We discuss a new approach of scalar field theory where the small field\ncontributions are treated perturbatively and the large field configurations\n(which are responsible for the asymptotic behavior of the perturbative series)\nare neglected. In two Borel summable lambda phi ^4 problems improved\nperturbative series can be obtained by this procedure. The modified series\nconverge towards values exponentially close to the exact ones. For lambda\nlarger than some critical value, the method outperforms Pade approximants and\nBorel summations. The method can also be used for series which are not Borel\nsummable such as the double-well potential series and provide a perturbative\napproach of the instanton contribution. Semi-classical methods can be used to\ncalculate the modified Feynman rules, estimate the error and optimize the field\ncutoff. We discuss Monte Carlo simulations in one and two dimensions which\nsupport the hypothesis of dilution of large field configurations used in these\nsemi-classical calculations. We show that Monte Carlo methods can be used to\ncalculate the modified perturbative series.",
        "positive": "Non-Hermitian Random Matrix Theory and Lattice QCD with Chemical\n  Potential: In quantum chromodynamics (QCD) at nonzero chemical potential, the\neigenvalues of the Dirac operator are scattered in the complex plane. Can the\nfluctuation properties of the Dirac spectrum be described by universal\npredictions of non-Hermitian random matrix theory? We introduce an unfolding\nprocedure for complex eigenvalues and apply it to data from lattice QCD at\nfinite chemical potential $\\mu$ to construct the nearest-neighbor spacing\ndistribution of adjacent eigenvalues in the complex plane. For intermediate\nvalues of $\\mu$, we find agreement with predictions of the Ginibre ensemble of\nrandom matrix theory, both in the confinement and in the deconfinement phase."
    },
    {
        "anchor": "Disconnected contribution to the LO HVP term of muon g-2 from ETMC: We present a lattice determination of the disconnected contributions to the\nleading-order hadronic vacuum polarization (HVP) to the muon anomalous magnetic\nmoment in the so-called short and intermediate time-distance windows. We employ\ngauge ensembles produced by the Extended Twisted Mass Collaboration (ETMC) with\n$N_f = 2 + 1 + 1$ flavours of Wilson twisted-mass clover-improved quarks with\nmasses approximately tuned to their physical value. We take the continuum limit\nemploying three lattice spacings at about 0.08, 0.07 and 0.06 fm.",
        "positive": "On the colour confinement and the minimal surface: In the analysis of the energy of the four-quark system obtained in the SU(2)\nlattice Monte Carlo, the f-model in which the transition potential is expressed\nin the form $f=f_c exp(-k_A b_s A-k_P\\sqrt{b_s}P)$, where A is the area and P\nis the perimeter of the Wilson loop, was successful in the simple\nconfigurations of the four quarks. In the case of tetrahedral geometry, an\nestimation of the minimal surface whose contours run the positions of the four\nquarks is necessary. We show that the regular surface approximation whose area\ncan be calculated analytically, is a good approximation for evaluating the\nminimal surface. The numerical value of the coefficient $k_A b_s$ is close to\n$2 fm^{-2}$ which is the density of the $Z_2$ vortex in the SU(2) lattice Monte\nCarlo."
    },
    {
        "anchor": "On chiral spin symmetry and the QCD phase diagram: Recently, an approximate $SU(4)$ chiral spin-flavour symmetry was observed in\nmultiplet patterns of QCD meson correlation functions, in a temperature range\nabove the chiral crossover. This symmetry is larger than the chiral symmetry of\nmassless QCD, and can only arise effectively when colour-electric quark-gluon\ninteractions dynamically dominate the quantum effective action. At temperatures\nabout three times the crossover temperature, these patterns disappear again,\nindicating the screening of colour-electric interactions, and the expected\nchiral symmetry is recovered. In this contribution we collect independent\nevidence for such an intermediate temperature range, based on screening masses\nand the pion spectral function. Both kinds of observables behave\nnon-perturbatively in this window, with resonance-like peaks for the pion and\nits first excitation disappearing gradually with temperature. Using symmetry\narguments and the known behaviour of screening masses at small densities, we\ndiscuss how this chiral spin symmetric band continues into the QCD phase\ndiagram.",
        "positive": "Simulation of Field Theories in Wavelet Representation: The field is expanded in a wavelet series and the wavelet coefficients are\nvaried in a simulation of the 2D $\\phi^4$ field theory. The drastically reduced\nautocorrelations result in a substantial decrease of computing requirements,\ncompared to those in local Metropolis simulations. A large part of the\nimprovement is shown to be the result of an additional freedom in the choice of\nthe allowed range of change at the Metropolis update of wavelet components,\nnamely the range can be optimized independently for all wavelet sizes."
    },
    {
        "anchor": "Kaons on the lattice: I review recent lattice results in kaon physics, particularly in the\ndetermination of V_{us} and the B_K parameter of K^0-\\bar{K}^0 mixing. I use\nlattice data to argue for the need of developing SU(2)_L \\times SU(2)_R chiral\nperturbation theory for kaon physics and discuss some recent progress in\nachieving this. In particular it is shown that for K_{\\ell 3} decays at q^2=0\n(where q is the momentum transfer between the kaon and the pion), the chiral\nlogarithms can be calculated in spite of the fact that the external pion\ncarries half the energy of the kaon (in the kaon's rest frame), because these\nlogarithms arise from soft internal loops. Future prospects, including\napplications to K\\to\\pi\\pi decays are discussed. The need to define and exploit\nrenormalization schemes which can simultaneously be implemented numerically in\nlattice simulations and used in higher-order perturbative calculations is\nexplained.",
        "positive": "The QCD Equation of state and critical end-point estimates at $\\mathcal\n  O(\u03bc_B^6)$: We present results for the QCD Equation of State at non-zero chemical\npotentials corresponding to the conserved charges in QCD using Taylor expansion\nupto sixth order in the baryon number, electric charge and strangeness chemical\npotentials. The latter two are constrained by the strangeness neutrality and a\nfixed electric charge to baryon number ratio. In our calculations, we use the\nHighly Improved Staggered Quarks (HISQ) discretization scheme at physical quark\nmasses and at different values of the lattice spacings to control lattice\ncut-off effects. Furthermore we calculate the pressure along lines of constant\nenergy density, which serve as proxies for the freeze-out conditions and\ndiscuss their dependence on $\\mu_B$ , which is necessary for hydrodynamic\nmodelling near freezeout. We also provide an estimate of the radius of\nconvergence of the Taylor series from the 6th order coefficients which provides\na new constraint on the location of the critical end-point in the T-$\\mu_B$\nplane of the QCD phase diagram."
    },
    {
        "anchor": "Studying the infrared region in Landau gauge QCD: We report on the progress we made in studying the infrared behavior of the\nghost and gluon dressing functions in Landau gauge. Related to this we also\ninvestigate a running coupling given in terms of those functions and compare\nour results to those coming from the Dyson-Schwinger approach. We present first\nnumerical results for the SU(3) ghost-ghost-gluon vertex renormalization\nconstant. In addition the spectrum of low-lying eigenvalues and eigenfunctions\nof the Faddeev-Popov operator is determined. The saturation of the ghost\npropagator in terms of those eigenvalues and eigenmodes is discussed at lower\nmomenta.",
        "positive": "First-Order Signals in Compact QED with Monopole Suppressed Boundaries: Pure gauge compact QED on hypercubic lattices is considered with periodically\nclosed monopole currents suppressed. We compute observables on sublattices\nwhich are nested around the centre of the lattice in order to locate regions\nwhere translation symmetry is approximately recovered. Our Monte Carlo\nsimulations on $24^4$-lattices give indications for a first-order nature of the\nU(1) phase transition."
    },
    {
        "anchor": "Wave functions and their use in spectroscopy and phenomenology: We describe the calculation of Coulomb gauge wave functions for light quark\nsystems, and their use as interpolating fields for excited state spectroscopy.",
        "positive": "On the continuum limit of Landau gauge gluon and ghost propagators in\n  SU(2) lattice gauge gluodynamics: We continue the systematic computation of Landau gauge gluon and ghost\npropagators of SU(2) gluodynamics using a sequence of increasing lattice sizes\nL^4 up to L=112 with corresponding \\beta-values chosen to keep the linear\nphysical size a(\\beta)L ~ 9.6 fm fixed. To extremize the Landau gauge\nfunctional we employ simulated annealing combined with subsequent\noverrelaxation. Renormalizing the propagators at momentum \\mu= 2.2 GeV we\nobserve quite strong lattice artifacts for the gluon propagator as well as for\nthe ghost dressing function within the momentum region q < 1.0 GeV. The\ndependence on the lattice spacing for the gluon propagator at lowest accessible\nphysical momentum values does not yet allow a simple extrapolation to the\ncontinuum limit. On the contrary, the running coupling derived from the bare\ndressing functions seems less affected by lattice artifacts."
    },
    {
        "anchor": "Evolution of Parton Distribution Functions in the Short-Distance\n  Factorization Scheme: Lattice QCD offers the possibility of computing parton distributions from\nfirst principles, although not in the usual $\\overline{MS}$ factorization\nscheme. We study in this paper the evolution of non-singlet parton distribution\nfunctions (PDFs) in the short-distance factorization scheme which notably\narises in lattice calculations in the pseudo-distribution approach. We provide\nan assessment of non-perturbative evolution of PDFs from already published\nlattice matrix elements, and show how this evolution can be used to reduce the\nfluctuation of the lattice data. We compare our result with expectations\nobtained thanks to a perturbative matching to $\\overline{MS}$. By highlighting\nthe limitations of the current computations, we advocate for a new strategy\nusing lattice calculations in small volume.",
        "positive": "Overlap for Majorana-Weyl fermions: The power of the overlap formalism is illustrated by regularizing theories\nbased on Majorana-Weyl fermions."
    },
    {
        "anchor": "Simulating the All-Order Hopping Expansion II: Wilson Fermions: We investigate the extension of the Prokof'ev-Svistunov worm algorithm to\nWilson lattice fermions in an external scalar field. We effectively simulate by\nMonte Carlo the graphs contributing to the hopping expansion of the two-point\nfunction on a finite lattice to arbitrary order. Tests are conducted for a\nconstant background field i. e. free fermions at some mass. For the method\nintroduced here this is expected to be a representative case. Its advantage is\nthat we know the exact answers and can thus make stringent tests on the\nnumerics. The approach is formulated in both two and three space-time\ndimensions. In D=2 Wilson fermions enjoy special positivity properties and the\nsimulation is similarly efficient as in the Ising model. In D=3 the method also\nworks at sufficiently large mass, but there is a hard sign problem in the\npresent formulation hindering us to take the continuum limit.",
        "positive": "A Lattice Formulation of Chiral Gauge Theories: We present a method for formulating gauge theories of chiral fermions in\nlattice field theory. The method makes use of a Wilson mass to remove doublers.\nGauge invariance is then restored by modifying the theory in two ways: the\nmagnitude of the fermion determinant is replaced with the square root of the\ndeterminant for a fermion with vector-like couplings to the gauge field; a\ndouble limit is taken, in which the lattice spacing associated with the fermion\nfield is sent to zero before the lattice spacing associated with the gauge\nfield. The method applies only to theories whose fermions are in an\nanomaly-free representation of the gauge group. We also present a related\ntechnique for computing matrix elements of operators involving fermion fields.\nAlthough the analyses of these methods are couched in weak-coupling\nperturbation theory, it is argued that the computational prescriptions are\ngauge invariant in the presence of a nonperturbative gauge-field configuration."
    },
    {
        "anchor": "Lattice simulations with G-parity Boundary Conditions: We discuss G-parity lattice boundary conditions as a means to impose momentum\non the pion ground state without breaking isospin symmetry. This technique is\nexpected to be critical for the precision measurement of\n$K\\rightarrow(\\pi\\pi)_{I=0}$ matrix elements where physical kinematics demands\nmoving pions in the final state and the statistical noise caused by\ndisconnected contributions will make it difficult to use multi-exponential fits\nto isolate this as an excited state. We present a formalism for computing\nhadronic Green's functions with G-parity boundary conditions, derive the\ndiscretized action and its symmetries, discuss how the strange quark can be\nintroduced and detail techniques for the numerical implementation of these\nboundary conditions. We demonstrate and test these methods using several\n$16^3\\times 32$ dynamical domain wall ensembles with a $420$ MeV pion mass and\nG-parity boundary conditions in one and two spatial directions.",
        "positive": "Stochastic Lattice Gas Model for a Predator-Prey System: We propose a stochastic lattice gas model to describe the dynamics of two\nanimal species population, one being a predator and the other a prey. This\nmodel comprehends the mechanisms of the Lotka-Volterra model. Our analysis was\nperformed by using a dynamical mean-field approximation and computer\nsimulations. Our results show that the system exhibits an oscillatory behavior\nof the population densities of prey and predators. For the sets of parameters\nused in our computer simulations, these oscillations occur at a local level.\nMean-field results predict synchronized collective oscillations."
    },
    {
        "anchor": "Dynamical quantum phase transitions in a noisy lattice gauge theory: Lattice gauge theories (LGTs) form an intriguing class of theories highly\nrelevant to both high-energy particle physics and low-energy condensed matter\nphysics with the rapid development of engineered quantum devices providing new\ntools to study e.g. dynamics of such theories. The massive Schwinger model is\nknown to exhibit intricate properties of more complicated theories and has\nrecently been shown to undergo dynamical quantum phase transitions out of\nequilibrium. With current technology, noise is inevitable and potentially fatal\nfor a successful quantum simulation. This paper studies the dynamics subject to\nnoise of a $(1+1)$D U$(1)$ quantum link model following a quench of the sign of\nthe mass term. We find that not only is the system capable of handling noise at\nrates realistic in NISQ-era devices, promising the possiblity to study the\ntarget dynamics with current technology, but the effect of noise can be\nunderstood in terms of simple models. Specifically the gauge-breaking nature of\nbit-flip channels results in exponential dampening of state amplitudes, and\nthus observables, which does not affect the structures of interest. This is\nespecially important as it demonstrates that the gauge theory can be\nsuccessfully studied with devices that only exhibit approximate gauge\ninvariance.",
        "positive": "Nucleon form factors with dynamical twisted mass fermions: The electromagnetic and axial form factors of the nucleon are evaluated in\ntwisted mass QCD with two degenerate flavors of light, dynamical quarks. The\naxial charge g_A, magnetic moment and the Dirac and Pauli radii are determined\nfor pion masses in the range 300 MeV to 500 MeV."
    },
    {
        "anchor": "Light Hadron Spectrum in Quenched Lattice QCD with Staggered Quarks: Without chiral extrapolation, we achieved a realistic nucleon to (\\rho)-meson\nmass ratio of (m_N/m_\\rho = 1.23 \\pm 0.04 ({\\rm statistical}) \\pm 0.02 ({\\rm\nsystematic})) in our quenched lattice QCD numerical calculation with staggered\nquarks. The systematic error is mostly from finite-volume effect and the\nfinite-spacing effect is negligible. The flavor symmetry breaking in the pion\nand (\\rho) meson is no longer visible. The lattice cutoff is set at 3.63 (\\pm)\n0.06 GeV, the spatial lattice volume is (2.59 (\\pm) 0.05 fm)(^3), and bare\nquarks mass as low as 4.5 MeV are used. Possible quenched chiral effects in\nhadron mass are discussed.",
        "positive": "Group-theoretical construction of finite-momentum and multi-particle\n  operators for lattice hadron spectroscopy: Determining the spectrum of hadronic excitations from Monte Carlo simulations\nrequires the use of interpolating operators that couple to multi-particle\nstates. Recent algorithmic advances have made the inclusion of multi-hadron\noperators in spectroscopy calculations a practical reality. In this talk, a\nprocedure for constructing a set of multi-hadron interpolators that project\nonto the states of interest is described. To aid in the interpretation of\nsimulation data, operators are designed to transform irreducibly under the\nlattice symmetry group. The identification of a set of optimal single-hadron\ninterpolators for states with non-zero momenta is an essential intermediate\nstep in this analysis."
    },
    {
        "anchor": "Finite temperature QCD at fixed Q with overlap fermions: We present some preliminary results of the project on finite temperature QCD\nwith overlap fermions at KEK. We performed a series of simulations to assess\nthe effects of fixing the topological sector at finite temperature and we will\nshow the first calculations of topological susceptibility and meson masses for\nquenched and full QCD.",
        "positive": "Effective Polyakov line action from the relative weights method: We apply the relative weights method (arXiv:1209.5697) to determine the\neffective Polyakov line action for SU(2) lattice gauge theory in the confined\nphase, at lattice coupling beta=2.2 and N_t=4 lattice spacings in the time\ndirection. The effective action turns out to be bilinear in the fundamental\nrepresentation Polyakov line variables, with a rather simple expression for the\nfinite range kernel. The validity of this action is tested by computing\nPolyakov line correlators, via Monte Carlo simulation, in both the effective\naction and the underlying lattice theory. It is found that the correlators in\neach theory are in very close agreement."
    },
    {
        "anchor": "Computing the Slope of the Isgur-Wise Function: We propose a method for evaluating the slope (and higher derivatives) of the\nIsgur-Wise function at the zero recoil point using lattice simulations. These\nderivatives are required for the extrapolation of the experimental data for\n$B\\rightarrow D^*l\\bar\\nu$ decays to the zero recoil point, from which the\n$V_{cb}$ element of the CKM-matrix can be determined.",
        "positive": "Non perturbative physics from NSPT: renormalons, the gluon condensate\n  and all that: Numerical Stochastic Perturbation Theory (NSPT) enables very high order\ncomputations in Lattice Gauge Theories. We report on the determination of the\ngluon condensate from lattice QCD measurements of the basic plaquette. This is\na long standing problem, which was eventually solved a few years ago in pure\ngauge. In this context NSPT is crucial: it is actually the only tool enabling\nthe subtraction of the power divergent contribution associated to the identity\noperator in the OPE for the plaquette. This subtraction is actually a delicate\nissue, since the perturbative expansion of the plaquette is on general ground\nexpected to be an asymptotic one, due to renormalons. This in turn results in\nambiguities and the separation of scales in the OPE does not correspond to a\nseparation of perturbative and non-perturbative contributions. All in all, one\nneeds to absorb the ambiguities attached to the perturbative series into the\ndefinition of the condensate itself, i.e. one needs a prescription. A possible\none amounts to summing the perturbative series up to its minimal term, which\nmeans computing up to orders which only NSPT can aim at. Our computation is the\nfirst one in QCD, with massless staggered fermions. In order to remove the\nzero-mode of the gauge field, twisted boundary conditions are adopted for the\nlatter, consistently coupled to fermions in the fundamental representation\nsupplemented with smell degrees of freedom."
    },
    {
        "anchor": "Hadron Wavefunctions as a Probe of a Two Color Baryonic Medium: The properties of the ground state of two-color QCD at non-zero baryon\nchemical potential $\\mu$ present an interesting problem in strongly-interacting\ngauge theory; in particular the nature of the physically-relevant degrees of\nfreedom in the superfluid phase in the post-onset regime $\\mu>m_\\pi/2$ still\nneeds clarification. In this study we present evidence for in-medium effects at\nhigh $\\mu$ by studying the wavefunctions of mesonic and diquark states using\northodox lattice simulation techniques, made possible by the absence of a Sign\nProblem for the model with $N_f=2$. Our results show that beyond onset the\nspatial extent of hadrons decreases as $\\mu$ grows, and that the wavefunction\nprofiles are consistent with the existence of a dynamically-gapped Fermi\nsurface in this regime.",
        "positive": "Hadron structure with light dynamical quarks: Generalized parton distributions encompass a wealth of information concerning\nthe three-dimensional quark and gluon structure of the nucleon, and thus\nprovide an ideal focus for the study of hadron structure using lattice QCD. The\nspecial limits corresponding to form factors and parton distributions are well\nexplored experimentally, providing clear tests of lattice calculations, and the\nlack of experimental data for more general cases provides opportunities for\ngenuine predictions and for guiding experiment. We present results from hybrid\ncalculations with improved staggered (Asqtad) sea quarks and domain wall\nvalence quarks at pion masses down to 350 MeV."
    },
    {
        "anchor": "Generalised parton distributions of the pion in partially-quenched\n  chiral perturbation theory: We consider the pion matrix elements of the isoscalar and isovector\ncombinations of the vector and tensor twist-two operators that determine the\nmoments of the various pion generalised parton distributions. Our analysis is\nperformed using partially-quenched chiral perturbation theory. We work in the\nSU(2) and SU(4|2) theories and present our results at infinite volume and also\nat finite volume where some subtleties arise. These results are useful for\nextrapolations of lattice calculations of these matrix elements at small\nmomentum transfer to the physical regime.",
        "positive": "Pion Distribution Amplitude from Lattice QCD: We have calculated the second moment of the pion light-cone distribution\namplitude using two flavors of dynamical (clover) fermions on lattices of\ndifferent volumes, lattice spacings between $0.06 \\, \\mathrm {fm}$ and $0.08 \\,\n\\mathrm {fm}$ and pion masses down to $m_\\pi\\sim 150 \\, \\mathrm {MeV}$. Our\nresult for the second Gegenbauer coefficient is $a_2 = 0.1364(154)(145)$ and\nfor the width parameter $\\langle \\xi^2 \\rangle = 0.2361(41)(39)$. Both numbers\nrefer to the scale $\\mu=2 \\, \\mathrm {GeV}$in the $\\overline{\\text{MS}}$\nscheme, the first error is statistical including the uncertainty of the chiral\nextrapolation, and the second error is the estimated uncertainty coming from\nthe nonperturbatively determined renormalization factors."
    },
    {
        "anchor": "Moments of generalized parton distributions and quark angular momentum\n  of the nucleon: The internal structure of hadrons is important for a variety of topics,\nincluding the hadron form factors, proton spin and spin asymmetry in polarized\nproton scattering.\n  For a systematic study generalized parton distributions (GPDs) encode\nimportant information on hadron structure in the entire impact parameter space.\nWe report on a computation of nucleon GPDs based on simulations with two\ndynamical non-perturbatively improved Wilson quarks with pion masses down to\n350MeV. We present results for the total angular momentum of quarks with chiral\nextrapolation based on covariant baryon chiral perturbation theory.",
        "positive": "Localisation of Dirac modes in finite-temperature $\\mathbb{Z}_2$ gauge\n  theory on the lattice: The low-lying Dirac modes become localised at the finite-temperature\ntransition in QCD and in other gauge theories, suggesting a general connection\nbetween their localisation and deconfinement. The simplest model where this\nconnection can be tested is $\\mathbb{Z}_2$ gauge theory in 2+1 dimensions. We\nshow that in this model the low modes in the staggered Dirac spectrum are\ndelocalised in the confined phase and become localised in the deconfined phase.\nWe also show that localised modes correlate with disorder in the Polyakov loop\nconfiguration, in agreement with the \"sea/island\" picture of localisation, and\nwith negative plaquettes. These results further support the conjecture that\nlocalisation and deconfinement are closely related."
    },
    {
        "anchor": "The SU(2) Confining Vacuum as a Dual Superconductor: We investigate the dual superconductivity hypothesis in pure SU(2) lattice\ngauge theory. We find evidence of the dual Meissner effect both in the\nmaximally Abelian gauge and without gauge fixing. We also obtain a rather good\nextimation of the string tension using the value of the London penetration\nlength.",
        "positive": "Confining properties of QCD at finite temperature and density: A disorder parameter detecting dual superconductivty of the vacuum is used as\na probe to characterize the confining properties of the phase diagram of two\ncolor QCD at finite temperature and density. We obtain evidence for the\ndisappearing of dual superconductivity (deconfinement) induced by a finite\ndensity of baryonic matter, as well as for a coincidence of this phenomenon\nwith the restoration of chiral symmetry both at zero and finite density. The\nsaturation transition induced by Pauli blocking is studied as well, and a\ngeneral warning is given about the possible effects that this unphysical\ntransition could have on the study of the QCD phase diagram at strong values of\nthe gauge coupling."
    },
    {
        "anchor": "Scaling study of the relativistic corrections to the static potential: The relativistic corrections to the static potential, i.e. the O(1/m)\ncorrection, the O(1/m^2) spin-dependent and momentum-dependent corrections are\ninvestigated in SU(3) lattice gauge theory. These corrections are relevant\ningredients of an effective field theory for heavy quarkonium called potential\nnonrelativistic QCD. Utilizing the multilevel algorithm for the field strength\ncorrelator on the quark-antiquark source, these corrections are determined at\nthe distances ranged from 0.25 to 1.2 fm. A reasonable scaling behavior and\nlong-range nonperturbative contributions are observed.",
        "positive": "Atiyah-Patodi-Singer index theorem for domain-wall fermion Dirac\n  operator: Recently, the Atiyah-Patodi-Singer(APS) index theorem attracts attention for\nunderstanding physics on the surface of materials in topological phases.\nAlthough it is widely applied to physics, the mathematical set-up in the\noriginal APS index theorem is too abstract and general (allowing non-trivial\nmetric and so on) and also the connection between the APS boundary condition\nand the physical boundary condition on the surface of topological material is\nunclear. For this reason, in contrast to the Atiyah-Singer index theorem,\nderivation of the APS index theorem in physics language is still missing. In\nthis talk, we attempt to reformulate the APS index in a \"physicist-friendly\"\nway, similar to the Fujikawa method on closed manifolds, for our familiar\ndomain-wall fermion Dirac operator in a flat Euclidean space. We find that the\nAPS index is naturally embedded in the determinant of domain-wall fermions,\nrepresenting the so-called anomaly descent equations."
    },
    {
        "anchor": "Isovector electromagnetic form factors of the nucleon from lattice QCD\n  and the proton radius puzzle: We present results for the isovector electromagnetic form factors of the\nnucleon computed on the CLS ensembles with $N_f=2+1$ flavors of\n$\\mathcal{O}(a)$-improved Wilson fermions and an $\\mathcal{O}(a)$-improved\nvector current. The analysis includes ensembles with four lattice spacings and\npion masses ranging from 130 MeV up to 350 MeV and mainly targets the low-$Q^2$\nregion. In order to remove any bias from unsuppressed excited-state\ncontributions, we investigate several source-sink separations between 1.0 fm\nand 1.5 fm and apply the summation method as well as explicit two-state fits.\nThe chiral interpolation is performed by applying covariant chiral perturbation\ntheory including vector mesons directly to our form factor data, thus avoiding\nan auxiliary parametrization of the $Q^2$ dependence. At the physical point, we\nobtain $\\mu=4.71(11)_{\\mathrm{stat}}(13)_{\\mathrm{sys}}$ for the nucleon\nisovector magnetic moment, in good agreement with the experimental value and\n$\\langle\nr_\\mathrm{M}^2\\rangle~=~0.661(30)_{\\mathrm{stat}}(11)_{\\mathrm{sys}}\\,~\\mathrm{fm}^2$\nfor the corresponding square-radius, again in good agreement with the value\ninferred from the $ep$-scattering determination [Bernauer et~al., Phys. Rev.\nLett., 105, 242001 (2010)] of the proton radius. Our estimate for the isovector\nelectric charge radius, $\\langle r_\\mathrm{E}^2\\rangle =\n0.800(25)_{\\mathrm{stat}}(22)_{\\mathrm{sys}}\\,~\\mathrm{fm}^2$, however, is in\nslight tension with the larger value inferred from the aforementioned\n$ep$-scattering data, while being in agreement with the value derived from the\n2018 CODATA average for the proton charge radius.",
        "positive": "Nucleon to Delta transition form factors with $N_F=2+1$ domain wall\n  fermions: We calculate the electromagnetic, axial and pseudo-scalar form factors of the\nNucleon to $\\Delta(1232)$ transition using two dynamical light degenerate\nquarks and a dynamical strange quark simulated with the domain wall fermion\naction. Results are obtained at lattice spacings $a = 0.114$ fm and $a=0.084$\nfm, with corresponding pion masses of $330$ MeV and $297$ MeV, respectively.\nHigh statistics measurements are achieved by utilizing the coherent sink\ntechnique. The dominant electromagnetic dipole form factor, the axial form\nfactors and the pseudo-scalar coupling are extracted to a good accuracy. This\nallows the investigation of the non-diagonal Goldberger-Treiman relation.\nParticular emphasis is given on the extraction of the sub-dominant\nelectromagnetic quadrupole form factors and their ratio to the dominant dipole\nform factor, $R_{EM}$ and $R_{SM}$, measured in experiment."
    },
    {
        "anchor": "On the ground state of Yang-Mills theory: We investigate the overlap of the ground state meson potential with sets of\nmesonic-trial wave functions corresponding to different gluonic distributions.\nWe probe the transverse structure of the flux tube through the creation of\nnon-uniform smearing profiles for the string of glue connecting two color\nsources in Wilson loop operator. The non-uniformly UV-regulated flux-tube\noperators are found to optimize the overlap with the ground state and display\ninteresting features in the ground state overlap.",
        "positive": "Multigrid for propagators of staggered fermions in four-dimensional\n  $SU(2)$ gauge fields: Multigrid (MG) methods for the computation of propagators of staggered\nfermions in non-Abelian gauge fields are discussed. MG could work in principle\nin arbitrarily disordered systems. The practical variational MG methods tested\nso far with a ``Laplacian choice'' for the restriction operator are not\ncompetitive with the conjugate gradient algorithm on lattices up to $18^4$.\nNumerical results are presented for propagators in $SU(2)$ gauge fields."
    },
    {
        "anchor": "Baryons in Partially Quenched Chiral Perturbation Theory: We include the lowest-lying octet- and decuplet-baryons into partially\nquenched chiral perturbation theory. Perturbing about the chiral limit of the\ngraded SU(6|3)_L x SU(6|3)_R flavor group of partially quenched QCD, we compute\nthe leading one-loop contributions to the octet-baryon masses, magnetic moments\nand matrix elements of isovector twist-2 operators. We work in the isospin\nlimit and keep two of the three sea quarks degenerate. The usefulness of the\nnon-unique extension of the electric charge matrix and the isovector twist-2\noperators from QCD to partially quenched QCD is discussed.",
        "positive": "Normalized entropy density of the 3D 3-state Potts model: Using a multicanonical Metropolis algorithm we have performed Monte Carlo\nsimulations of the 3D 3-state Potts model on $L^3$ lattices with L=20, 30, 40,\n50. Covering a range of inverse temperatures from $\\beta_{\\min}=0$ to\n$\\beta_{\\max}=0.33$ we calculated the infinite volume limit of the entropy\ndensity $s(\\beta)$ with its normalization obtained from $s(0)=\\ln 3$. At the\ntransition temperature the entropy and energy endpoints in the ordered and\ndisordered phase are estimated employing a novel reweighting procedure. We also\nevaluate the transition temperature and the order-disorder interface tension.\nThe latter estimate increases when capillary waves are taken into account."
    },
    {
        "anchor": "Review of Hadron Structure Calculations on a Lattice: I present a review of the current status and the most recent achievements in\nlattice QCD calculations of hadron structure. First, I overview the status and\nsystematic uncertainties of nucleon structure \"benchmark\" quantities that are\nwell known from experiments and serve as a reference point for the validity of\nlattice QCD methods. Next, I discuss the current status of calculations of form\nfactors of the nucleon and highlight some recent results for other hadrons that\nare important for understanding their internal dynamics. Wave functions of\nhadrons and their excitations may also be studied in lattice QCD, and I\nillustrate it with two recent examples of such calculations. Finally, I discuss\nin detail the state of calculations pertaining to the nucleon spin puzzle.",
        "positive": "Majorana fermions and CP-invariance of chiral gauge theories on the\n  lattice: The construction of massless Majorana fermions with chiral Yukawa couplings\non the lattice is considered. We find topological obstructions tightly linked\nto those underlying the Nielsen-Ninomiya no-go theorem. In contradistinction to\nchiral fermions the obstructions originate only from the combination of the\nDirac action and the Yukawa term. These findings are used to construct a\nchirally invariant lattice action. We also show that the path integral of this\ntheory is given by the Pfaffian of the corresponding Dirac operator. As an\napplication of the approach set-up here we construct a CP-invariant lattice\naction of a chiral gauge theory, based on a lattice adaptation of charge\nconjugation and parity transformation in the continuum."
    },
    {
        "anchor": "Scaling properties of many-fermion systems from MCRG studies: Monte Carlo renormalization group methods were designed to study the phase\nstructure and critical behavior of statistical systems. They are well suited to\ndetermine the running coupling and to investigate the properties of fixed\npoints of gauge-fermion models, including the existence of conformal infrared\nfixed points in many-fermion systems. I discuss the implementation of the\n2-lattice matching method and present results for SU(3) gauge theories with\nN_f=0,12 and 16 fundamental fermion flavors.",
        "positive": "Nucleon Isovector Axial Form Factors: We present results for the isovector axial vector form factors obtained using\nthirteen 2+1+1-flavor highly improved staggered quark (HISQ) ensembles\ngenerated by the MILC collaboration. The calculation of nucleon two- and\nthree-point correlation functions has been done using Wilson-clover fermions.\nIn the analysis of these data, we quantify the sensitivity of the results to\nstrategies used for removing excited state contamination and invoke the\npartially conserved axial current relation between the form factors to choose\nbetween them. Our data driven analysis includes removing contributions from\nmultihadron $N \\pi$ states that make significant contributions. Our final\nresults are: $g_A = 1.295 (50)_\\text{stat}\\,(24)_\\text{sys}$ for the axial\ncharge; $g_S = 1.085 (50)_\\text{stat}\\, (103)_\\text{sys}$ and $g_T = 0.991\n(21)_\\text{stat}\\, (10)_\\text{sys}$ for the scalar and tensor charges; $\\langle\nr_A^2 \\rangle = 0.418 (33)_\\text{stat} (34)_\\text{sys}$ fm${}^2$ for the mean\nsquared axial charge radius, $g_P^\\ast = 9.03(47)_\\text{stat}(42)_\\text{sys} $\nfor the induced pseudoscalar charge; and $g_{\\pi NN} =\n14.14(81)_\\text{stat}(85)_\\text{sys}$ for the pion-nucleon coupling. We also\nprovide a parameterization of the axial form factor $G_A(Q^2)$ over the range\n$0 \\le Q^2 \\le 1$ GeV${}^2$ for use in phenomenology and a comparison with\nother lattice determinations. We find that the various lattice data agree\nwithin 10\\% but are significantly different from the extraction of $G_A(Q^2)$\nfrom the $\\nu$-deuterium scattering data."
    },
    {
        "anchor": "Thimble regularization at work for Gauge Theories: from toy models\n  onwards: A final goal for thimble regularization of lattice field theories is the\napplication to lattice QCD and the study of its phase diagram. Gauge theories\npose a number of conceptual and algorithmic problems, some of which can be\naddressed even in the framework of toy models. We report on our progresses in\nthis field, starting in particular from first successes in the study of one\nlink models.",
        "positive": "Fermion loop simulation of the lattice Gross-Neveu model: We present a numerical simulation of the Gross-Neveu model on the lattice\nusing a new representation in terms of fermion loops. In the loop\nrepresentation all signs due to Pauli statistics are eliminated completely and\nthe partition function is a sum over closed loops with only positive weights.\nWe demonstrate that the new formulation allows to simulate volumes which are\ntwo orders of magnitude larger than those accessible with standard methods."
    },
    {
        "anchor": "Phases and fractal structures of three-dimensional simplicial gravity: We study phases and fractal structures of three-dimensional simplicial\nquantum gravity by the Monte-Carlo method. After measuring the surface area\ndistribution (SAD) which is the three-dimensional analog of the loop length\ndistribution (LLD) in two-dimensional quantum gravity, we classify the fractal\nstructures into three types: (i) in the hot (strong coupling) phase, strong\ngravity makes the space-time one crumpled mother universe with small\nfluctuating branches around it. This is a crumpled phase with a large Hausdorff\ndimension $d_{\\mbox{\\tiny H}} \\simeq 5$. The topologies of cross-sections are\nextremely complicated. (ii) at the critical point, we observe that the\nspace-time is a fractal-like manifold which has one mother universe with small\nand middle size branches around it. The Hausdorff dimension is $d_{\\mbox{\\tiny\nH}} \\simeq 4$. We observe some scaling behaviors for the cross-sections of the\nmanifold. This manifold resembles the fractal surface observed in\ntwo-dimensional quantum gravity. (iii) in the cold (weak coupling) phase, the\nmother universe disappears completely and the space-time seems to be the\nbranched-polymer with a small Hausdorff dimension $d_{\\mbox{\\tiny H}} \\simeq\n2$. Almost all of the cross-sections have the spherical topology $S^2$ in the\ncold phase.",
        "positive": "Comment on \"On the Origin of the OZI Rule in QCD\", by N. Isgur and H. B.\n  Thacker: We comment on the recent paper (hep-lat/0005006) by Isgur and Thacker on the\norigin of the OZI rule in QCD. We show that instantons explain the sign and\nmagnitude of the observed OZI-violating amplitude in all mesonic channels, not\njust in the $\\eta'$ channel. We comment on the role of instantons in hadronic\nspectroscopy and the relation between instantons and the large $N_c$ limit of\nQCD."
    },
    {
        "anchor": "A Renormalization Group for Dynamical Triangulations in Arbitrary\n  Dimensions: A block spin renormalization group approach is proposed for the dynamical\ntriangulation formulation of quantum gravity in arbitrary dimensions.\nRenormalization group flow diagrams are presented for the three-dimensional and\nfour-dimensional theories near their respective transitions.",
        "positive": "The Equation of State for QCD with 2+1 Flavors of Quarks: We report results for the interaction measure, pressure and energy density\nfor nonzero temperature QCD with 2+1 flavors of improved staggered quarks. In\nour simulations we use a Symanzik improved gauge action and the Asqtad $O(a^2)$\nimproved staggered quark action for lattices with temporal extent $N_t=4$ and\n6. The heavy quark mass $m_s$ is fixed at approximately the physical strange\nquark mass and the two degenerate light quarks have masses $m_{ud} =0.1m_s$ or\n$0.2m_s$. The calculation of the thermodynamic observables employs the integral\nmethod where energy density and pressure are obtained by integration over the\ninteraction measure."
    },
    {
        "anchor": "Multigrid Monte Carlo with higher cycles in the Sine Gordon model: We study the dynamical critical behavior of multigrid Monte Carlo for the two\ndimensional Sine Gordon model on lattices up to 128 x 128. Using piecewise\nconstant interpolation, we perform a W-cycle (gamma=2). We examine whether one\ncan reduce critical slowing down caused by decreasing acceptance rates on large\nblocks by doing more work on coarser lattices. To this end, we choose a higher\ncycle with gamma = 4. The results clearly demonstrate that critical slowing\ndown is not reduced in either case.",
        "positive": "Matrix formulation of superspace on 1D lattice with two supercharges: Following the approach developed by some of the authors in recent papers and\nusing a matrix representation for the superfields, we formulate an exact\nsupersymmetric theory with two supercharges on a one dimensional lattice. In\nthe superfield formalism supersymmetry transformations are uniquely defined and\ndo not suffer of the ambiguities recently pointed out by some authors. The\naction can be written in a unique way and it is invariant under all\nsupercharges. A modified Leibniz rule applies when supercharges act on a\nsuperfield product and the corresponding Ward identities take a modified form\nbut hold exactly at least at the tree level, while their validity in presence\nof radiative corrections is still an open problem and is not considered here."
    },
    {
        "anchor": "Interaction of confining vortices in SU(2) lattice gauge theory: Center projection of SU(2) lattice gauge theory allows to isolate magnetic\nvortices as confining configurations. The vortex density scales according to\nthe renormalization group, implying that the vortices are physical objects\nrather than lattice artifacts. Here, the binary correlations between points at\nwhich vortices pierce a given plane are investigated. We find an attractive\ninteraction between the vortices. The correlations show the correct scaling\nbehavior and are therefore physical. The range of the interaction is found to\nbe (0.4 +/- 0.2) fm, which should be compared with the average planar vortex\ndensity of approximately 2 vortices/fm^2. We comment on the implications of\nthese results for recent discussions of the Casimir scaling behavior of higher\ndimensional representation Wilson loops in the vortex confinement picture.",
        "positive": "Effective electroweak Hamiltonian in the gradient-flow formalism: The effective electroweak Hamiltonian in the gradient-flow formalism is\nconstructed for the current-current operators through next-to-next-to-leading\norder QCD. The results are presented for two common choices of the operator\nbasis. This paves the way for a consistent matching of perturbatively evaluated\nWilson coefficients and non-perturbative matrix elements evaluated by lattice\nsimulations."
    },
    {
        "anchor": "Electromagnetic effects on the light hadron spectrum: For some time, the MILC Collaboration has been studying electromagnetic\neffects on light mesons. These calculations use fully dynamical QCD, but only\nquenched photons, which suffices to NLO in XPT. That is, the sea quarks are\nelectrically neutral, while the valence quarks carry charge. For the photons we\nuse the non-compact formalism. We have new results with lattice spacing as\nsmall as 0.045 fm and a large range of volumes. We consider how well chiral\nperturbation theory describes these results and the implications for light\nquark masses",
        "positive": "The QCD deconfinement transition for heavy quarks and all baryon\n  chemical potentials: Using combined strong coupling and hopping parameter expansions, we derive an\neffective three-dimensional theory from thermal lattice QCD with heavy Wilson\nquarks. The theory depends on traced Polyakov loops only and correctly reflects\nthe centre symmetry of the pure gauge sector as well as its breaking by finite\nmass quarks. It is valid up to certain orders in the lattice gauge coupling and\nhopping parameter, which can be systematically improved. To its current order\nit is controlled for lattices up to N_\\tau\\sim 6 at finite temperature. For\nnonzero quark chemical potentials, the effective theory has a fermionic sign\nproblem which is mild enough to carry out simulations up to large chemical\npotentials. Moreover, by going to a flux representation of the partition\nfunction, the sign problem can be solved. As an application, we determine the\ndeconfinement transition and its critical end point as a function of quark mass\nand all chemical potentials."
    },
    {
        "anchor": "A multigrid accelerated eigensolver for the Hermitian Wilson-Dirac\n  operator in lattice QCD: Eigenvalues of the Hermitian Wilson-Dirac operator are of special interest in\nseveral lattice QCD simulations, e.g., for noise reduction when evaluating\nall-to-all propagators. In this paper we present a Davidson-type eigensolver\nthat utilizes the structural properties of the Hermitian Wilson-Dirac operator\n$Q$ to compute eigenpairs of this operator corresponding to small eigenvalues.\nThe main idea is to exploit a synergy between the (outer) eigensolver and its\n(inner) iterative scheme which solves shifted linear systems. This is achieved\nby adapting the multigrid DD-$\\alpha$AMG algorithm to a solver for shifted\nsystems involving the Hermitian Wilson-Dirac operator. We demonstrate that\nupdating the coarse grid operator using eigenvector information obtained in the\ncourse of the generalized Davidson method is crucial to achieve good\nperformance when calculating many eigenpairs, as our study of the local\ncoherence shows. We compare our method with the commonly used software-packages\nPARPACK and PRIMME in numerical tests, where we are able to achieve significant\nimprovements, with speed-ups of up to one order of magnitude and a near-linear\nscaling with respect to the number of eigenvalues. For illustration we compare\nthe distribution of the small eigenvalues of $Q$ on a $64\\times 32^3$ lattice\nwith what is predicted by the Banks-Casher relation in the infinite volume\nlimit.",
        "positive": "Numerical sign problem and the tempered Lefschetz thimble method: The numerical sign problem is a major obstacle to the quantitative\nunderstanding of many important physical systems with first-principles\ncalculations. Typical examples for such systems include finite-density QCD,\nstrongly-correlated electron systems and frustrated spin systems, as well as\nthe real-time dynamics of quantum systems. In this talk, we argue that the\n\"tempered Lefschetz thimble method\" (TLTM) [M. Fukuma and N. Umeda,\narXiv:1703.00861] and its extension, the \"worldvolume tempered Lefschetz\nthimble method\" (WV-TLTM) [M. Fukuma and N. Matsumoto, arXiv:2012.08468], may\nbe a reliable and versatile solution to the sign problem. We demonstrate the\neffectiveness of the algorithm by exemplifying a successful application of\nWV-TLTM to the Stephanov model, which is an important toy model of\nfinite-density QCD. We also discuss the computational scaling of WV-TLTM."
    },
    {
        "anchor": "A Lattice Evaluation of the Deep-Inelastic Structure Functions of the\n  Nucleon: The lower moments of the unpolarized and polarized deep-inelastic structure\nfunctions of the nucleon are calculated on the lattice. The calculation is done\nwith Wilson fermions and for three values of the hopping parameter $\\kappa$, so\nthat we can perform the extrapolation to the chiral limit. Particular emphasis\nis put on the renormalization of lattice operators. The renormalization\nconstants, which lead us from lattice to continuum operators, are computed\nperturbatively to one loop order as well as non-perturbatively.",
        "positive": "Study of the order of the phase transition in pure U(1) gauge theory\n  with Villain action: We address the question of the order of the deconfinement phase transition of\nfour dimensional U(1) lattice gauge theory. Simulations of the Z-gauge theory\ndual to the Villain action on toroidal lattices up to lattice sizes of 28^4\ngive results consistent with both, a vanishing and a nonvanishing discontinuity\nin the thermodynamic limit. A decision on the order of the phase transition\nrequires still larger lattice sizes."
    },
    {
        "anchor": "On internal structure of the heavy-light mesons: We compute the radial distributions of the vector and axial charge density as\nwell as of the matter density in the heavy-light mesons on the lattice. The\nresults for the lowest lying static heavy-light mesons and their first excited\ncounterparts are obtained with Nf=2 dynamical quarks of Wilson (Clover) type\nand with the various improved static heavy quark actions. From these\ndistributions we were able to compute the corresponding charges and slopes of\nthe form factors (i.e. <r^2>). Those results are also presented, and briefly\ndiscussed too.",
        "positive": "Higher partial wave contamination in finite-volume 1-to-2 transitions: In their seminal work, Lellouch and L\\\"uscher derived a conversion factor\nrelating a finite-volume matrix element, calculable using numerical lattice\nQCD, with the infinite-volume decay amplitude for $K \\to \\pi \\pi$. The\nconversion factor depends on the $\\pi \\pi \\to \\pi \\pi$ scattering amplitude\nwith the same total isospin (either zero or two) as the $\\pi \\pi$ decay\nchannel. Although an infinite tower of $\\pi \\pi \\to \\pi \\pi$ partial-wave\ncomponents affect the conversion factor, the $S$-wave ($\\ell=0$) component is\nexpected to dominate, and only this contribution is included in the well-known\nLellouch-L\\\"uscher factor, with other $\\pi \\pi \\to \\pi \\pi$ partial-wave\namplitudes formally set to zero. However, as the precision of lattice\ncalculations increases, it may become important to assess the systematic\nuncertainty arising from this approximation. With this motivation, we compare\nthe $S$-wave-only results with those truncated at the next contaminating\npartial wave: the $G$-wave ($\\ell=4$) for zero total momentum in the\nfinite-volume frame and the $D$-wave ($\\ell=2$) otherwise. Using the general\nframework for $1 \\overset{\\mathcal J}{\\to} 2$ transitions, we quantify the\neffect of higher partial waves for systems with zero and non-zero total\nmomentum as well as with anti-periodic boundary conditions, presenting both\ngeneric numerical examples and results for realistic $\\pi \\pi$ amplitudes taken\nfrom chiral perturbation theory and dispersive analysis. We also consider the\naccidental degeneracy occurring in the 8$^{\\text {th}}$ excited state of the\nzero-momentum system. This exhibits qualitatively new features at $\\ell=4$, not\nseen in the $\\ell=0$ truncation."
    },
    {
        "anchor": "Non-perturbatively improved clover action for SU(2) gauge + fundamental\n  and adjoint representation fermions: The research of strongly coupled beyond-the-standard-model theories has\ngenerated significant interest in non-abelian gauge field theories with\ndifferent number of fermions in different representations. Motivated by the\nincreased interest to various technicolor scenarios, we study the\nnon-perturbative improvement of the Wilson-clover action with SU(2) gauge\nfields and 2 flavors of fermions in the fundamental and adjoint\nrepresentations. The Sheikholeslami-Wohlert coefficients are fixed using\nSchroedinger functional boundary conditions. The adjoint representation theory\nis a candidate for a \"minimal technicolor\" theory, already studied on the\nlattice using unimproved Wilson fermions.",
        "positive": "Critical analysis of two-dimensional classical XY model: We consider the two-dimensional classical XY model on a square lattice in the\nthermodynamic limit using tensor renormalization group and precisely determine\nthe critical temperature corresponding to the Berezinskii-Kosterlitz-Thouless\n(BKT) phase transition to be 0.89290(5) which is an improvement compared to\nearlier studies using tensor network methods."
    },
    {
        "anchor": "Practical all-to-all propagators for lattice QCD: A new method for computing all elements of the lattice quark propagator is\nproposed. The method combines the spectral decomposition of the propagator,\ncomputing the lowest eigenmodes exactly, with noisy estimators which are\n'diluted', i.e. taken to have support only on a subset of time, space, spin or\ncolour. We find that the errors are dramatically reduced compared to\ntraditional noisy estimator techniques.",
        "positive": "What can Lattice QCD theorists learn from NMR spectroscopists?: Euclidean-time hadron correlation functions computed in Lattice QCD (LQCD)\nare modeled by a sum of decaying exponentials, reminiscent of the exponentially\ndamped sinusoid models of free induction decay (FID) in Nuclear Magnetic\nResonance (NMR) spectroscopy. We present our initial progress in studying how\ndata modeling techniques commonly used in NMR perform when applied to LQCD\ndata."
    },
    {
        "anchor": "Application of Quadrature Methods for Re-Weighting in Lattice QCD: Re-weighting is a useful tool that has been employed in Lattice QCD in\ndifferent contexts including, tuning the strange quark mass, approaching the\nlight quark mass regime, and simulating electromagnetic fields on top of QCD\ngauge configurations. In case of re-weighting the sea quark mass, the\nre-weighting factor is given by the ratio of the determinants of two Dirac\noperators $D_a$ and $D_b$. A popular approach for computing this ratio is to\nuse a pseudofermion representation of the determinant of the composite operator\n$\\Omega=D_a(D_b^\\dagger D_b)^{-1} D_a^\\dagger$. Here, we study using quadrature\nmethods together with noise vectors to compute the ratio of determinants. We\nshow that, with quadrature methods each determinant can be computed separately\nusing the operators $\\Omega_a=D_a^\\dagger D_a$ and $\\Omega_b=D_b^\\dagger D_b$.\nWe also discuss using bootstrap re-sampling to remove the bias from the\ndeterminant estimator.",
        "positive": "Measurement of hadron masses in 2-color finite density QCD: We investigate hadron spectra in 2-color QCD using lattice simulation with\n$N_{f}=2$ at low temperature and finite density in which there appears not only\nthe hadronic phase but also the superfluid phase. We first calculate the pion\nand rho meson spectrum, which is well-known from previous works. The spectral\nordering of these mesons flips around the quark chemical potential\n$\\mu=m^{0}_{\\pi}/2$ ($m^{0}_{\\pi}$: the pion mass at $\\mu=0$), where the phase\ntransition between the hadronic and superfluid phases occurs. For $\\mu \\gtrsim\nm^{0}_{\\pi}/2$, the effective mass for the pion linearly increases while the\none for the rho meson monotonically decreases. Furthermore, we measure hadron\nspectra with the isospin $I=0$ and the angular momentum $J^{P}=0^{\\pm}$. The\neffective masses for the meson, diquark, and antidiquark with the same quantum\nnumber become degenerate just below $\\mu = m^{0}_{\\pi}/2$, and the three\nhadrons have the same mass in the superfluid phase. It suggests that mixing\noccurs between spectra associating with mesons and baryons due to the\n$U(1)_{B}$ symmetry breaking. This phenomenon can be explained in the linear\nsigma model with the approximate $SU(4)$ Pauli-Gursey symmetry."
    },
    {
        "anchor": "Pion spectral properties above the chiral crossover of QCD: Spectral functions encode a wealth of information about the dynamics of any\ngiven system, and the determination of their non-perturbative characteristics\nis a long-standing problem in quantum field theory. Whilst numerical\nsimulations of lattice QCD provide ample data for various Euclidean correlation\nfunctions, the inversion required to extract spectral functions is an ill-posed\nproblem. In this work, we pursue previously established constraints imposed by\nfield locality at finite temperature $T$, namely that spectral functions\npossess a non-perturbative representation which generalises the well-known\nK\\\"{a}ll\\'{e}n-Lehmann spectral form to $T>0$. Using this representation, we\nanalyse lattice QCD data of the spatial pseudo-scalar correlator in the\ntemperature range $220-960 \\, \\text{MeV}$, and obtain an analytic expression\nfor the corresponding spectral function, with parameters fixed by the data.\nFrom the structure of this spectral function we find evidence for the existence\nof a distinct pion state above the chiral pseudo-critical temperature\n$T_{\\text{pc}}$, and contributions from its first excitation, which gradually\nmelt as the temperature increases. As a non-trivial test, we find that the\nextracted spectral function reproduces the corresponding temporal lattice\ncorrelator data for $T=220 \\, \\text{MeV}$.",
        "positive": "Higgs and W boson spectrum from lattice simulations: The spectrum of energy levels is computed for all available angular momentum\nand parity quantum numbers in the SU(2)-Higgs model, with parameters chosen to\nmatch experimental data from the Higgs-W boson sector of the standard model.\nSeveral multi-boson states are observed, with and without linear momentum, and\nall are consistent with weakly-interacting Higgs and W bosons. The creation\noperators used in this study are gauge-invariant so, for example, the Higgs\noperator is quadratic rather than linear in the Lagrangian's scalar field."
    },
    {
        "anchor": "Finite volume analysis on systematics of the derivative expansion in HAL\n  QCD method: We study the convergence of the derivative expansion in HAL QCD method from\nthe finite volume analysis. Employing the (2+1)-flavor lattice QCD data\nobtained at nearly physical light quark masses $(m_\\pi, m_K) \\simeq (146, 525)$\nMeV and the physical charm quark mass, we study two representative systems,\n$\\Omega\\Omega$ and $\\Omega_{ccc}\\Omega_{ccc}$ in the $^1S_0$ channel, where\nboth systems were found to have a shallow bound state in our previous studies.\nThe HAL QCD potentials are determined at the leading-order in the derivative\nexpansion, from which finite-volume eigenmodes are obtained. Utilizing the\neigenmode projection, we find that the correlation functions are dominated by\nthe ground state (first excited state) in the case of $\\Omega\\Omega$\n($\\Omega_{ccc}\\Omega_{ccc}$). In both $\\Omega\\Omega$ and\n$\\Omega_{ccc}\\Omega_{ccc}$, the spectra obtained from eigenmode-projected\ntemporal correlators are found to be consistent with those from the HAL QCD\npotential for both the ground and first excited state. These results show that\nthe derivative expansion is well converged in these systems, and also provide a\nfirst explicit evidence that the HAL QCD method enables us to reliably extract\nthe binding energy of the ground state even from the correlator dominated by\nexcited scattering states.",
        "positive": "Ising Spins on a Gravitating Sphere: We investigated numerically an Ising model coupled to two-dimensional\nEuclidean gravity with spherical topology, using Regge calculus with the $dl/l$\npath-integral measure to discretize the gravitational interaction. Previous\nstudies of this system with toroidal topology have shown that the critical\nbehavior of the Ising model remains in the flat-space Onsager universality\nclass, contrary to the predictions of conformal field theory and matrix models.\nImplementing the spherical topology as triangulated surfaces of\nthree-dimensional cubes, we find again strong evidence that the critical\nexponents of the Ising transition are consistent with the Onsager values, and\nthat KPZ exponents are definitely excluded."
    },
    {
        "anchor": "Continuum limit of field theories regularized on a random lattice: The continuum limit and scaling properties of an asymptotically free field\ntheory regularized on a random lattice are compared with those on a regular\nsquare lattice. We work on random lattices parametrized by a degree of\n``randomness'' $\\kappa$. We show that the continuum limit exists and different\n$\\kappa$ are related by a finite renormalization.",
        "positive": "Critical dynamics of relativistic diffusion: We study the dynamics of self-interacting scalar fields with $Z_2$ symmetry\ngoverned by a relativistic Israel-Stuart type diffusion equation in the\nvicinity of a critical point. We calculate spectral functions of the order\nparameter in mean-field approximation as well as using first-principles\nclassical-statistical lattice simulations in real-time. We observe that the\nspectral functions are well-described by single Breit-Wigner shapes. Away from\ncriticality, the dispersion matches the expectations from the mean-field\napproach. At the critical point, the spectral functions largely keep their\nBreit-Wigner shape, albeit with non-trivial power-law dispersion relations. We\nextract the characteristic time-scales as well as the dynamic critical exponent\n$z$, verifying the existence of a dynamic scaling regime. In addition, we\nderive the universal scaling functions implied by the Breit-Wigner shape with\ncritical power-law dispersion and show that they match the data. Considering\nequations of motion for a system coupled to a heat bath as well as an isolated\nsystem, we perform this study for two different dynamic universality classes,\nboth in two and three spatial dimensions."
    },
    {
        "anchor": "Study of a new simulation algorithm for dynamical quarks on the APE-100\n  parallel computer: First results on the autocorrelation behaviour of a recently proposed fermion\nalgorithm by M. L\\\"uscher are presented and discussed. The occurence of\nunexpected large autocorrelation times is explained. Possible improvements are\ndiscussed.",
        "positive": "QCD Phase Transition with Strange Quark in Wilson Formalism for Fermions: The nature of QCD phase transition is studied with massless up and down\nquarks and a light strange quark, using the Wilson formalism for quarks on a\nlattice with the temporal direction extension $N_t=4$. We find that the phase\ntransition is first order in the cases of both about 150 MeV and 400 MeV for\nthe strange quark mass. These results together with those for three degenerate\nquarks suggest that QCD phase transition in nature is first order."
    },
    {
        "anchor": "Message passing on the QCDSP supercomputer: The QCDSP machines were designed for lattice gauge calculations. For planning\nit is crucial to explore this architecture for other computationally intensive\ntasks. Here I describe an implementation of a simple message passing scheme.\nWith the objective being simplicity, I introduce a small number of generic\nfunctions for manipulating a large data set spread over the machine. I test the\nscheme on three applications: a fast Fourier transform, arbitrary dimension\nSU(N) pure lattice gauge theory, and the manipulation of Fermionic Fock states\nthrough a distributed hash table. These routines compile both on QCDSP and a\nUnix workstation.",
        "positive": "I=2 Pion Scattering Phase Shift with Wilson Fermions: We present a lattice QCD calculation of the scattering phase shift for the\nI=2 $S$-wave two-pion system using the finite size method proposed by\nL\\\"uscher. We work in the quenched approximation employing the standard\nplaquette action at $\\beta=5.9$ for gluons and the Wilson fermion action for\nquarks. The phase shift is extracted from the energy eigenvalues of the\ntwo-pion system, which are obtained by a diagonalization of the pion 4-point\nfunction evaluated for a set of relative spatial momenta. In order to change\nmomentum of the two-pion system, calculations are carried out on $24^3\\times\n60$, $32^3\\times 60$, and $48^3\\times 60$ lattices. The phase shift is\nsuccessfully calculated over the momentum range $0 < p^2 < 0.3 {\\rm GeV}^2$."
    },
    {
        "anchor": "Dynamical Compactification of Extra Dimensions in the Euclidean IKKT\n  Matrix Model via Spontaneous Symmetry Breaking: The IKKT matrix model has been conjectured to provide a promising\nnonperturbative formulation of superstring theory. In this model, spacetime\nemerges dynamically from the microscopic matrix degrees of freedom in the\nlarge-N limit, and Monte Carlo simulations of the Lorentzian version provide\nevidence of an emergent (3+1)-dimensional expanding space-time. In this talk,\nwe discuss the Euclidean version of the IKKT matrix model and provide evidence\nof dynamical compactification of the extra dimensions via the spontaneous\nsymmetry breaking (SSB) of the 10D rotational symmetry. We perform numerical\nsimulations of a system with a severe complex action problem by using the\ncomplex Langevin method (CLM). The CLM suffers from the singular-drift problem\nand we deform the model in order to avoid it. We study the SSB pattern as we\nvary the deformation parameter and we conclude that the original model has an\nSO(3) symmetric vacuum, in agreement with previous calculations using the\nGaussian expansion method (GEM). We employ the GEM to the deformed model and we\nobtain results consistent with the ones obtained by CLM.",
        "positive": "Miscellanies of $ K^0 - \\bar{K}^0 $ mixing and $ B_K $: We have computed $ B_K $, using two different methods with staggered fermions\non a $ 16^3 \\times 40 $ lattice at $ \\beta = 5.7 $ with two dynamical flavors\nof a mass 0.01. % Using an improved wall source method, we have studied a\nseries of non-degenerate quark antiquark pairs and observed no effect on $ B_K\n$, although effects were seen on the individual terms making up $ B_K $."
    },
    {
        "anchor": "Confinement/Deconfinement in 4D compact QED on the lattice: It has long been known that there is a phase transition between confined and\nunconfined phases of compact pure gauge QED on the lattice. In this work we\nreport three manifestations of this phase change as seen in the Landau gauge\nphoton propagator, the static potential, and distribution of Dirac Strings in\nthe gauge fixed configurations. Each of these was calculated with large\nlattices with volumes: $32^4$, $48^4$ and $96^4$. We show that the confined\nphase manifests with a Yukawa type propagator with a dynamically generated mass\ngap, a linearly increasing potential, and a significant concentration of Dirac\nstrings while the unconfined phase appears consistent with the continuum\nresults: a free propagator, a near constant long-distance potential, and a\nsmall concentration of Dirac strings trending towards zero. Furthermore, the\nphoton propagator is investigated in detail near the transition between the two\nphases.",
        "positive": "Spontaneous Breaking of Flavor Symmetry and Parity in the\n  Nambu-Jona-Lasinio Model with Wilson Fermions: We study the lattice \\njl~model with two flavors of Wilson fermions in the\nlarge $N$ limit, where $N$ is the number of `colors'. For large values of the\nfour-fermion coupling we find a phase in which both, flavor symmetry and\nparity, are spontaneously broken. In accordance with general expectations there\nare three massless pions on the phase boundary, but only two of them remain\nmassless inside the broken phase. This is analogous to earlier results obtained\nin lattice QCD, indicating that this behavior is a very general feature of the\nWilson term."
    },
    {
        "anchor": "Overlap fermion with the topology conserving gauge action: We investigate the distribution of low-lying eigenmodes of hermitian\nWilson-Dirac operator, $H_W$, with the gauge action whose form is designed to\navoid topology change, as well as with the standard plaquette action. On the\nquenched lattices, the former gauge action exhibits less density of low-lying\neigenmodes of $H_W$ compared to the latter at the same lattice spacing. We also\nshow preliminary results for the dynamical simulation with two flavors of\noverlap fermions.",
        "positive": "Advances in machine-learning-based sampling motivated by lattice quantum\n  chromodynamics: Sampling from known probability distributions is a ubiquitous task in\ncomputational science, underlying calculations in domains from linguistics to\nbiology and physics. Generative machine-learning (ML) models have emerged as a\npromising tool in this space, building on the success of this approach in\napplications such as image, text, and audio generation. Often, however,\ngenerative tasks in scientific domains have unique structures and features --\nsuch as complex symmetries and the requirement of exactness guarantees -- that\npresent both challenges and opportunities for ML. This Perspective outlines the\nadvances in ML-based sampling motivated by lattice quantum field theory, in\nparticular for the theory of quantum chromodynamics. Enabling calculations of\nthe structure and interactions of matter from our most fundamental\nunderstanding of particle physics, lattice quantum chromodynamics is one of the\nmain consumers of open-science supercomputing worldwide. The design of ML\nalgorithms for this application faces profound challenges, including the\nnecessity of scaling custom ML architectures to the largest supercomputers, but\nalso promises immense benefits, and is spurring a wave of development in\nML-based sampling more broadly. In lattice field theory, if this approach can\nrealize its early promise it will be a transformative step towards\nfirst-principles physics calculations in particle, nuclear and condensed matter\nphysics that are intractable with traditional approaches."
    },
    {
        "anchor": "3-D lattice simulation of the electroweak phase transition at small\n  Higgs mass: We study the electroweak phase transition by lattice simulations of an\neffective 3-dimensional theory, for a Higgs mass of about $35 GeV$. In the\nbroken symmetry phase our results on masses and the Higgs condensate are\nconsistent with 2-loop perturbative results. However, we find a\nnon-perturbative lowering of the transition temperature, similar to the one\npreviously found at $m_H = 80 GeV$. For the symmetric phase, bound state masses\nand the static force are determined and compared with results for pure $SU(2)$\ntheory.",
        "positive": "Three relativistic neutrons in a finite volume: We generalize the relativistic field-theoretic (RFT) three-particle\nfinite-volume formalism to systems of three identical, massive, spin-$1/2$\nfermions, such as three neutrons. This allows, in principle, for the\ndetermination of the three-neutron interaction from the finite-volume spectrum\nof three-neutron states, which can be obtained from lattice QCD calculations."
    },
    {
        "anchor": "Measuring the entropy from shifted boundary conditions: We explore a new computational strategy for determining the equation of state\nof the SU(3) Yang-Mills theory. By imposing shifted boundary conditions, the\nentropy density is computed from the vacuum expectation value of the\noff-diagonal components T_{0k} of the energy-momentum tensor. A step-scaling\nfunction is introduced to span a wide range in temperature values. We present\npreliminary numerical results for the entropy density and its step-scaling\nfunction obtained at eight temperature values in the range T_c - 15 T_c. At\neach temperature, discretization effects are removed by simulating the theory\nat several lattice spacings and by extrapolating the results to the continuum\nlimit. Finite-size effects are always kept below the statistical errors. The\nabsence of ultraviolet power divergences and the remarkably small\ndiscretization effects allow for a precise determination of the step-scaling\nfunction in the explored temperature range. These findings establish this\nstrategy as a viable solution for an accurate determination of the equation of\nstate in a wide range of temperature values.",
        "positive": "Unexpected Spin-Off from Quantum Gravity: We propose a novel way of investigating the universal properties of spin\nsystems by coupling them to an ensemble of causal dynamically triangulated\nlattices, instead of studying them on a fixed regular or random lattice.\nSomewhat surprisingly, graph-counting methods to extract high- or\nlow-temperature series expansions can be adapted to this case. For the\ntwo-dimensional Ising model, we present evidence that this ameliorates the\nsingularity structure of thermodynamic functions in the complex plane, and\nimproves the convergence of the power series."
    },
    {
        "anchor": "Apparent convergence of Pad\u00e9 approximants for the crossover line in\n  finite density QCD: We propose a novel Bayesian method to analytically continue observables to\nreal baryochemical potential $\\mu_B$ in finite density QCD. Taylor coefficients\nat $\\mu_B=0$ and data at imaginary chemical potential $\\mu_B^I$ are treated on\nequal footing. We consider two different constructions for the Pad\\'e\napproximants, the classical multipoint Pad\\'e approximation and a mixed\napproximation that is a slight generalization of a recent idea in Pad\\'e\napproximation theory. Approximants with spurious poles are excluded from the\nanalysis. As an application, we perform a joint analysis of the available\ncontinuum extrapolated lattice data for both pseudocritical temperature $T_c$\nat $\\mu_B^I$ from the Wuppertal-Budapest Collaboration and Taylor coefficients\n$\\kappa_2$ and $\\kappa_4$ from the HotQCD Collaboration. An apparent\nconvergence of $[p/p]$ and $[p/p+1]$ sequences of rational functions is\nobserved with increasing $p.$ We present our extrapolation up to $\\mu_B\\approx\n600$ MeV.",
        "positive": "First study of the gluon-quark-antiquark static potential in SU(3)\n  Lattice QCD: We study the long distance interaction for hybrid hadrons, with a static\ngluon, a quark and an antiquark with lattice QCD techniques. A Wilson loop\nadequate to the static hybrid three-body system is developed and, using a 24^3\nx 48 periodic lattice with beta=6.2 and a ~ 0.075 fm, two different geometries\nfor the gluon-quark segment and the gluon-antiquark segment are investigated.\nWhen these segments are perpendicular, the static potential is compatible with\nconfinement realized with a pair of fundamental strings, one linking the gluon\nto the quark and another linking the same gluon to the antiquark. When the\nsegments are parallel and superposed, the total string tension is larger and\nagrees with the Casimir Scaling measured by Bali. This can be interpreted with\na type-II superconductor analogy for the confinement in QCD, with repulsion of\nthe fundamental strings and with the string tension of the first topological\nexcitation of the string (the adjoint string) larger than the double of the\nfundamental string tension."
    },
    {
        "anchor": "The non-perturbative QCD Debye mass from a Wilson line operator: According to a proposal by Arnold and Yaffe, the non-perturbative\ng^2T-contribution to the Debye mass in the deconfined QCD plasma phase can be\ndetermined from a single Wilson line operator in the three-dimensional pure\nSU(3) gauge theory. We extend a previous SU(2) measurement of this quantity to\nthe physical SU(3) case. We find a numerical coefficient which is more accurate\nand smaller than that obtained previously with another method, but still very\nlarge compared with the naive expectation: the correction is larger than the\nleading term up to T ~ 10^7 T_c, corresponding to g^2 ~ 0.4. At moderate\ntemperatures T ~ 2 T_c, a consistent picture emerges where the Debye mass is\nm_D ~ 6T, the lightest gauge invariant screening mass in the system is ~ 3T,\nand the purely magnetic operators couple dominantly to a scale ~ 6T. Electric\n(~ gT) and magnetic (~ g^2T) scales are therefore strongly overlapping close to\nthe phase transition, and the colour-electric fields play an essential role in\nthe dynamics.",
        "positive": "Lattice QCD calculation of the two-photon exchange contribution to the\n  muonic-hydrogen Lamb shift: We develop a method for lattice QCD calculation of the two-photon exchange\n(TPE) contribution to the muonic-hydrogen Lamb shift. To demonstrate the\nfeasibility of this method, we also present an exploratory study with a gauge\nensemble at $m_\\pi = 142$ MeV. By adopting the infinite-volume reconstruction\n(IVR) method along with an optimized subtraction scheme, we obtain a\npreliminary result of the TPE contribution which agrees well with previous\ncalculation using other methods and one magnitude smaller compare to the large\n$\\sim300~\\mu$eV discrepancy for the proton radius puzzle."
    },
    {
        "anchor": "Chiral limit of QCD: This talk contains an analysis of quenched chiral perturbation theory and its\nconsequences. The chiral behavior of a number of quantities such as the pion\nmass $m_\\pi^2$, the Bernard-Golterman ratios $R$ and $\\chi$, the masses of\nnucleons, and the kaon B-parameter are examined to see if the singular terms\ninduced by the additional Goldstone boson,$\\eta'$, are visible in present data.\nThe overall conclusion (different from what I presented at the lattice meeting)\nof this analysis is that, with some caveats on the extra terms induced by\n$\\eta'$ loops, the standard expressions break down when extrapolating the\nquenched data with $m_q < m_s/2$ to physical light quarks. I then show that due\nto the single and double poles in the quenched $\\eta'$, the axial charge of the\nproton cannot be calculated using the Adler-Bell-Jackiw anomaly condition. I\nconclude with a review of the status of the calculation of light quark masses\nfrom lattice QCD.",
        "positive": "Renormalization of non-local gluon operators in lattice perturbation\n  theory: In this study, we investigate the renormalization of a complete set of\ngauge-invariant non-local gluon operators up to one-loop in lattice\nperturbation theory. Our computations have been performed in both dimensional\nand lattice regularizations, using the Wilson gluon action, leading to the\nrenormalization functions in the modified Minimal Subtraction\n$(\\overline{\\text{MS}})$ scheme, as well as conversion factors from the\nmodified regularization invariant $(RI')$ scheme to $\\overline{\\text{MS}}$."
    },
    {
        "anchor": "Induced QCD I: Theory: We explore an alternative discretization of continuum SU(N_c) Yang-Mills\ntheory on a Euclidean spacetime lattice, originally introduced by Budzcies and\nZirnbauer. In this discretization the self-interactions of the gauge field are\ninduced by a path integral over N_b auxiliary boson fields, which are coupled\nlinearly to the gauge field. The main progress compared to earlier approaches\nis that N_b can be as small as N_c. In the present paper we (i) extend the\nproof that the continuum limit of the new discretization reproduces Yang-Mills\ntheory in two dimensions from gauge group U(N_c) to SU(N_c), (ii) derive\nrefined bounds on N_b for non-integer values, and (iii) perform a perturbative\ncalculation to match the bare parameter of the induced gauge theory to the\nstandard lattice coupling. In follow-up papers we will present numerical\nevidence in support of the conjecture that the induced gauge theory reproduces\nYang-Mills theory also in three and four dimensions, and explore the\npossibility to integrate out the gauge fields to arrive at a dual formulation\nof lattice QCD.",
        "positive": "Improved B -> pi l nu_l form factors from the lattice: We present the results of a lattice computation of the form factors for B^0\n->pi^- l^+nu_l decays near zero-recoil. These results will allow a\ndetermination of the CKM matrix element |Vub| when measurements of the\ndifferential decay rate become available. We also provide models for\nextrapolation of the form factors and rate to the full recoil range. Our\ncomputation is performed in the quenched approximation to QCD on a 24^3x48\nlattice at beta=6.2, using a non-perturbatively O(a)-improved action. The\nmasses of all light valence quarks involved are extrapolated to their physical\nvalues."
    },
    {
        "anchor": "Towards a lattice calculation of the coefficients of the QCD chiral\n  Lagrangian: We discuss a general strategy to compute the coefficients of QCD chiral\nLagrangian by using the lattice regularization of QCD with Wilson fermions.\nThis procedure requires the introduction of an effective Lagrangian for lattice\nQCD as an intermediate step in the calculation. The continuum QCD chiral\nLagrangian can be then obtained by expanding the lattice effective Lagrangian\nin increasing powers of the external momenta. A suitable renormalization\nprocedure is required to account for the chiral symmetry breaking introduced by\nthe Wilson term in the lattice action. In anticipation of a numerical\nsimulation, the lattice effective Lagrangian is computed analytically and\ninvestigated in the strong coupling and large $N$ limit",
        "positive": "Chiral behavior of kaon semileptonic form factors in lattice QCD with\n  exact chiral symmetry: We calculate the kaon semileptonic form factors in lattice QCD with three\nflavors of dynamical overlap quarks. Gauge ensembles are generated at pion\nmasses as low as 290 MeV and at a strange quark mass near its physical value.\nWe precisely calculate relevant meson correlators using the all-to-all quark\npropagator. Twisted boundary conditions and the reweighting technique are\nemployed to vary the momentum transfer and the strange quark mass. We discuss\nthe chiral behavior of the form factors by comparing with chiral perturbation\ntheory and experiments."
    },
    {
        "anchor": "Exact Extended Supersymmetry on a Lattice: Twisted N=4 Super Yang-Mills\n  in Three Dimensions: We propose a lattice formulation of three dimensional super Yang-Mills model\nwith a twisted N=4 supersymmetry. The extended supersymmetry algebra of all the\neight supercharges is fully and exactly realized on the lattice with a modified\n\"Leibniz rule\". The formulation we employ here is a three dimensional extension\nof manifestly gauge covariant method which was developed in our previous\nproposal of Dirac-Kaehler twisted N=2 super Yang-Mills on two dimensional\nlattice. The twisted N=4 supersymmetry algebra is geometrically realized on a\nthree dimensional lattice with link supercharges and the use of \"shifted\"\n(anti-)commutators. A possible solution to the recent critiques on the link\nformulation will be discussed.",
        "positive": "Density of states approach for lattice gauge theory with a $\u03b8$-term: We discuss a new strategy for treating the complex action problem of lattice\nfield theories with a $\\theta$-term based on density of states (DoS) methods.\nThe key ingredient is to use open boundary conditions where the topological\ncharge is not quantized to integers and the density of states is sufficiently\nwell behaved such that it can be computed precisely with recently developed DoS\ntechniques. After a general discussion of the approach and the role of the\nboundary conditions, we analyze the method for 2-d U(1) lattice gauge theory\nwith a $\\theta$-term, a model that can be solved in closed form. We show that\nin the continuum limit periodic and open boundary conditions describe the same\nphysics and derive the DoS, demonstrating that only for open boundary\nconditions the density is sufficiently well behaved for a numerical evaluation.\nWe conclude our proof of principle analysis with a small test simulation where\nwe numerically compute the density and compare it with the analytical result."
    },
    {
        "anchor": "Chiral symmetry restoration in QCD with many flavours: We discuss the phases of QCD in the parameter space spanned by the number of\nlight flavours and the temperature with respect to the realisation of chiral\nand conformal symmetries. The intriguing interplay of these symmetries is best\nstudied by means of lattice simulations, and some selected results from our\nrecent work are presented here.",
        "positive": "Harmonic Oscillator Prepotentials in SU(2) Lattice Gauge Theory: We write the SU(2) lattice gauge theory Hamiltonian in (d+1) dimensions in\nterms of prepotentials which are the SU(2) fundamental doublets of harmonic\noscillators. The Hamiltonian in terms of prepotentials has $SU(2) \\otimes U(1)$\nlocal gauge invariance. In the strong coupling limit, the color confinement in\nthis formulation is due to the U(1) gauge group. We further solve the $SU(2)\n\\otimes U(1)$ Gauss law to characterize the physical Hilbert space in terms of\na set of gauge invariant integers. We also obtain certain novel gauge invariant\noperators in terms of the above oscillators. The corresponding prepotential\nformulation of SU(N) lattice gauge theory is also simple and discussed."
    },
    {
        "anchor": "Direct computational approach to lattice supersymmetric quantum\n  mechanics: We propose a numerical method of estimating various physical quantities in\nlattice (supersymmetric) quantum mechanics. The method consists only of\ndeterministic processes such as computing a product of transfer matrix, and has\nno statistical uncertainties. We use the numerical quadrature to define the\ntransfer matrix as a finite dimensional matrix, and find that it effectively\nworks by rescaling variable for sufficiently small lattice spacings. For a\nlattice supersymmetric quantum mechanics, the correlators can be estimated\nwithout statistical errors, and the effective masses coincide with the exact\nsolution within very small errors less than 0.001%. The SUSY Ward identity is\nalso precisely studied in compared with the Monte-Carlo method. Our method is\nnot limited to a lattice SUSY quantum mechanics, but is also applicable to any\nother lattice models of quantum mechanics.",
        "positive": "The Stefan-Boltzmann law: SU(2) versus SO(3) lattice gauge theory: We investigate the high temperature limit of SU(2) and SO(3) lattice gauge\ntheory, respectively. In particular, we study the Stefan-Boltzmann constant in\nboth cases. As is well known, the Stefan-Boltzmann constant extracted from\nSU(2) lattice gauge theory by incorporating finite size effects is smaller than\nthe continuum value which assumes three gluon degrees of freedom. On the other\nhand, the extrapolation of our SO(3) lattice data comes much closer to the\ncontinuum value. This rises the question whether SU(2) and SO(3) lattice gauge\ntheories represent different quantum theories in the continuum limit."
    },
    {
        "anchor": "Non-perturbative insights into the spectral properties of QCD at finite\n  temperature: In quantum field theories at finite temperature spectral functions describe\nhow particle systems behave in the presence of a thermal medium. Although data\nfrom lattice simulations can in principle be used to determine spectral\nfunction characteristics, existing methods rely on the extraction of these\nquantities from temporal correlators, which requires one to circumvent an\nill-posed inverse problem. In these proceedings we report on a recent approach\nthat instead utilises the non-perturbative constraints imposed by field\nlocality to extract spectral function information directly from spatial\ncorrelators. In particular, we focus on the application of this approach to\nlattice QCD data of the spatial pseudo-scalar meson correlator in the\ntemperature range $220-960 \\, \\text{MeV}$, and outline why this data supports\nthe conclusion that there exists a distinct pion state above the chiral\npseudo-critical temperature $T_{\\!\\text{pc}}$.",
        "positive": "GW Meson Scattering on a Staggered Sea: We discuss the structure of the NLO corrections to the chiral formulae for\nmesonic scattering processes in mixed action simulations using Ginsparg-Wilson\nvalence quarks and staggered sea quarks. In particular, we show that the\nanalytic contribution of the NLO chiral Lagrangian is the same as in QCD. We\nalso comment on how this result restricts the dependence of the amplitudes on\nthe unknown parameter C_Mix appearing in the chiral theory appropriate for\nthese systems. We conclude with some comments on the explicit scattering\nlengths."
    },
    {
        "anchor": "Dominance of Sign Geometry and the Homogeneity of the Fundamental\n  Topological Structure: We propose and support the possibility that the shape of topological density\n2-point function in pure-glue QCD is crucially, and possibly entirely,\ndetermined by the space-time folding (geometry) of the double-sheet\nsign-coherent structure of Ref.[1], while the distribution of topological\ndensity within individual sheets only determines the overall magnitude of the\ncorrelator at finite physical distances. A specific manifestation of this,\ndiscussed here, is that the shape of the correlation function (encoding e.g.\nthe masses of pseudoscalar glueballs) is reproduced upon the replacement q(x)\n-> sgn(q(x)), i.e. by considering the double sheet of the same space-time\ngeometry but with constant magnitude of topological density. Combined with\nprevious results on the fundamental topological structure, this suggests that a\ncollective degree of freedom describing topological fluctuations of QCD vacuum\ncan be viewed as a global space-filling homogeneous double membrane. Selected\npossibilities for practical uses of this are discussed.",
        "positive": "Relativistic three-particle quantization condition for nondegenerate\n  scalars: The formalism relating the relativistic three-particle infinite-volume\nscattering amplitude to the finite-volume spectrum has been developed thus far\nonly for identical or degenerate particles. We provide the generalization to\nthe case of three nondegenerate scalar particles with arbitrary masses. A key\nquantity in this formalism is the quantization condition, which relates the\nspectrum to an intermediate K matrix. We derive three versions of this\nquantization condition, each a natural generalization of the corresponding\nresults for identical particles. In each case we also determine the integral\nequations relating the intermediate K matrix to the three-particle scattering\namplitude, $\\mathcal M_3$. The version that is likely to be most practical\ninvolves a single Lorentz-invariant intermediate K matrix, $\\widetilde{\\mathcal\nK}_{\\rm df,3}$. The other versions involve a matrix of K matrices, with\nelements distinguished by the choice of which initial and final particles are\nthe spectators. Our approach should allow a straightforward generalization of\nthe relativistic approach to all other three-particle systems of interest."
    },
    {
        "anchor": "Revealing Topological Structure in the SU(2) Vacuum: In this paper we derive a simple parametrization of the cycling method\ndeveloped by us in our earlier work. The new method, called renormalization\ngroup (RG) mapping, consists of a series of carefully tuned APE-smearing steps.\nWe study the relation between cycling and RG mapping. We also investigate in\ndetail how smooth instantons and instanton-anti-instanton pairs behave under\nthe RG mapping transformation. We use the RG mapping technique to study the\ntopological susceptibility and instanton size distribution of SU(2) gauge\ntheory. We find scaling in both quantities in a wide range of coupling values.\nOur result for the topological susceptibility, chi^1/4=220(6) MeV, agrees with\nour earlier results.",
        "positive": "QCD plasma instability and thermalisation at heavy ion collisions: Under suitable non-equilibrium conditions QCD plasma can develop plasma\ninstabilities, where some modes of the plasma grow exponentially. It has been\nargued that these instabilities can play a significant role in the\nthermalisation of the plasma in heavy-ion collision experiments. We study the\ninstability in SU(2) plasmas using the hard thermal loop effective lattice\ntheory, which is suitable for studying real-time evolution of long wavelength\nmodes in the plasma. We observe that under suitable conditions the plasma can\nindeed develop an instability which can grow to a very large magnitude,\nnecessary for the rapid thermalisation in heavy-ion collisions."
    },
    {
        "anchor": "Determination of Reference Scales for Wilson Gauge Action from\n  Yang--Mills Gradient Flow: A parametrization of the lattice spacing ($a$) in terms of the bare coupling\n($\\beta$) for the SU(3) Yang--Mills theory with the Wilson gauge action is\ngiven in a wide range of~$\\beta$. The Yang--Mills gradient flow with respect to\nthe flow time~$t$ for the dimensionless observable, $t\\frac{d}{dt}t^2\\langle\nE(t)\\rangle$, is utilized to determine the parametrization. With fine lattice\nspacings ($6.3\\le\\beta\\le7.5$) and large lattice volumes ($N_{\\rm\ns}=64$--$128$), the discretization and finite-volume errors are significantly\nreduced to the same level as the statistical error.",
        "positive": "Shearing approach to gauge invariant Trotterization: Universal quantum simulations of gauge field theories are exposed to the risk\nof gauge symmetry violations when it is not known how to compile the desired\noperations exactly using the available gate set. In this letter, we show how\ntime evolution can be compiled in an Abelian gauge theory -- if only\napproximately -- without compromising gauge invariance, by graphically\nmotivating a block-diagonalization procedure. When gauge invariant interactions\nare associated with a \"spatial network\" in the space of discrete quantum\nnumbers, it is seen that cyclically shearing the spatial network converts\nsimultaneous updates to many quantum numbers into conditional updates of a\nsingle quantum number: ultimately, this eliminates any need to pass through\n(and acquire overlap onto) unphysical intermediate configurations. Shearing is\nexplicitly applied to gauge-matter and magnetic interactions of lattice QED.\nThe features that make shearing successful at preserving Abelian gauge symmetry\nmay also be found in non-Abelian theories, bringing one closer to gauge\ninvariant simulations of quantum chromodynamics."
    },
    {
        "anchor": "Comparison between models of QCD with and without dynamical charm quarks: We investigate the influence of dynamical charm quarks on observables that\ndepend explicitly on the charm quark fields, like the pseudo-scalar and vector\nmasses $m_{\\eta_c}$ and $m_{J/\\psi}$, the hyperfine splitting\n$(m_{J/\\psi}-m_{\\eta_c})/m_{\\eta_c}$, the charm quark mass and the meson decay\nconstants. For this purpose, instead of working in full QCD we study a\nsimplified setup. We simulate two theories: $N_f= 0$ QCD and QCD with $N_f= 2$\ndynamical quarks at the charm mass. The absence of light quarks allows us to\nreach extremely fine lattice spacings (0.02 fm < a < 0.05 fm) which are crucial\nfor reliable continuum extrapolations. Our main result is a comparison of\nvarious quantities in the continuum limit. For the hyperfine splitting we find\nthat the effects of a dynamical charm quark are below our statistical precision\nof $2\\%$.",
        "positive": "Geometrical Origin of Tricritical Points of various U(1) Lattice Models: We review the dual relationship between various compact U(1) lattice models\nand Abelian Higgs models, the latter being the disorder field theories of\nline-like topological excitations in the systems. We point out that the\npredicted first-order transitions in the Abelian Higgs models (Coleman-Weinberg\nmechanism) are, in three dimensions, in contradiction with direct numerical\ninvestigations in the compact U(1) formulation since these yield continuous\ntransitions in the major part of the phase diagram. In four dimensions, there\nare indications from Monte Carlo data for a similar situation. Concentrating on\nthe strong-coupling expansion in terms of geometrical objects, surfaces or\nlines, with certain statistical weights, we present semi-quantitative arguments\nexplaining the observed cross-over from first-order to continuous transitions\nby the balance between the lowest two weights (``2:1 ratio'') of these\ngeometrical objects."
    },
    {
        "anchor": "Nucleon generalized form factors from two-flavor lattice QCD: We determine the generalized form factors, which correspond to the second\nMellin moment (i.e., the first $x$-moment) of the generalized parton\ndistributions of the nucleon at leading twist. The results are obtained using\nlattice QCD with $N_f=2$ nonperturbatively improved Wilson fermions, employing\na range of quark masses down to an almost physical value with a pion mass of\nabout 150 MeV. We also present results for the isovector quark angular momentum\nand for the first $x$-moment of the transverse quark spin density. We compare\ntwo different fit strategies and find that directly fitting the ground state\nmatrix elements to the functional form expected from Lorentz invariance and\nparametrized in terms of form factors yields comparable, and usually more\nstable results than the traditional approach where the form factors are\ndetermined from an overdetermined linear system based on the fitted matrix\nelements.",
        "positive": "Dual Superconductor Mechanism of Confinement on the Lattice: We investigate the dual superconductor mechanism of confinement for pure\nSU(2) lattice gauge theory in the maximally abelian gauge. We focus on the the\ndual Meissner effect. We find that the transverse distribution of the\nlongitudinal chromoelectric field due to a static quark-antiquark pair\nsatisfies the dual London equation. Moreover we show that the size of the flux\ntube scales according to asymptotic freedom."
    },
    {
        "anchor": "Update on $\\varepsilon_K$ with lattice QCD inputs: We report updated results for $\\varepsilon_K$, the indirect CP violation\nparameter in neutral kaons, which is evaluated directly from the standard model\nwith lattice QCD inputs. We use lattice QCD inputs to fix $\\bar{B}_K$,\n$|V_{cb}|$, $\\xi_0$, $\\xi_2$, $|V_{us}|$, and $m_c(m_c)$. Since Lattice 2016,\nthe UTfit group has updated the Wolfenstein parameters in the angle-only-fit\nmethod, and the HFLAV group has also updated $|V_{cb}|$. Our results show that\nthe evaluation of $\\varepsilon_K$ with exclusive $|V_{cb}|$ (lattice QCD\ninputs) has $4.0\\sigma$ tension with the experimental value, while that with\ninclusive $|V_{cb}|$ (heavy quark expansion based on OPE and QCD sum rules)\nshows no tension.",
        "positive": "Spectroscopy with Local Multi-hadron Interpolators in Lattice QCD: The positive-parity nucleon spectrum is studied in 2 + 1 flavour lattice QCD\nin an attempt to discover novel low-lying energy eigenstates in the region of\nthe Roper resonance. In this work, we employ standard three-quark interpolating\nfields and introduce new local five-quark meson-baryon operators that hold the\npossibility of revealing new states that have been missed in previous studies.\nMotivated by phenomenological arguments, five-quark interpolators based on the\n$\\sigma{N}$, $\\pi{N}$ and $a_0{N}$ channels are constructed. Despite the\nintroduction of qualitatively different operators, no novel energy levels are\nextracted near the regime of the Roper resonance."
    },
    {
        "anchor": "Cutoff effects of the gradient flow for fermions: I analyze cutoff effects of the gradient flow for Wilson-type fermions. I\nshow that with a proper choice of the higher dimensional fields in the Symanzik\neffective theory, O($a$) improvement of the action is achieved changing the\ninitial conditions of the gradient flow equation.",
        "positive": "Many flavor QCD as exploration of the walking behavior with the\n  approximate IR fixed point: We present the first report of the LatKMI collaboration on the the lattice\nQCD simulation performed at the KMI computer, \"$\\varphi$\", for the cases of 4\nflavors and 8 flavors, the latter being expected to be a candidate for the\nwalking technicolor having an approximate scale invariance near the infrared\nfixed point. The simulation was carried out based on the highly improved\nstaggered quark (HISQ) action. In this proceedings, we report preliminary\nresults on the spectrum, analyzed through the chiral perturbation theory and\nthe finite-size hyperscaling. We observe qualitatively different behavior of\nthe 8-flavor case in contrast to the 4-flavor case which shows clear indication\nof the hadronic phase as in the usual QCD."
    },
    {
        "anchor": "Detailed study of quark-antiquark flux tubes and flux tube recombination: In this work we compute the color fields in the mediator plane between a\nstatic quark and a static antiquark using quenched lattice QCD. In special, we\nsee the effect of the quark-antiquark distance on the flux tube. To obtain this\nresults an improved multihit technique is developed and an extend smearing\ntechnique is used. Then, we also discuss the flux-tubes in a system composed of\ntwo quarks and two antiquarks. The ground and first excited states fields are\nstudied for different dispositions of the system.",
        "positive": "A High Statistics Lattice Calculation of The B-meson Binding Energy: We present a high statistics lattice calculation of the B--meson binding\nenergy $\\overline{\\Lambda}$ of the heavy--quark inside the pseudoscalar\nB--meson. Our numerical results have been obtained from several independent\nnumerical simulations at $\\beta=6.0$, $6.2$ and $6.4$, and using, for the meson\ncorrelators, the results obtained by the APE group at the same values of\n$\\beta$. Our best estimate, obtained by combining results at different values\nof $\\beta$, is $\\overline{\\Lambda}=180^{+30}_{-20}$ MeV. For the\n$\\overline{MS}$ running mass, we obtain\n$\\overline{m}_{b}(\\overline{m}_{b})=4.15 \\pm 0.05 \\pm 0.20$ GeV, in reasonable\nagreement with previous determinations. The systematic error is the truncation\nof the perturbative series in the matching condition of the relevant operator\nof the Heavy Quark Effective Theory."
    },
    {
        "anchor": "Technical notes on a 2-d lattice O(N) model problem: This paper provides a technical companion to M. Aguado and E. Seiler,\nhep-lat/0406041, in which the fate of perturbation theory in the thermodynamic\nlimit is discussed for the O(N) model on a 2d lattice and different boundary\nconditions. The techniques used to compute perturbative coefficients are\nexplained, and results for all boundary conditions considered reviewed in\ndetail.",
        "positive": "Critical properties of 2D Z(N) vector models for N>4: We investigate the critical properties of two-dimensional Z(N) vector models\nfor N larger than 4. In particular, critical points of the two phase\ntransitions are located and some critical indices are determined. We study also\nthe behavior of the helicity modulus and the dependence of the critical points\non N."
    },
    {
        "anchor": "Continuum limit of two-dimensional multiflavor scalar gauge theories: We address the interplay between local and global symmetries by analyzing the\ncontinuum limit of two-dimensional multicomponent scalar lattice gauge\ntheories, endowed by non-Abelian local and global invariance. These theories\nare asymptotically free. By exploiting Monte Carlo simulations and finite-size\nscaling techniques, we provide numerical results concerning the universal\nbehavior of such models in the critical regime. Our results support the\nconjecture that two-dimensional multiflavor scalar models have the same\ncontinuum limit as the $\\sigma$-models associated with symmetric spaces that\nhave the same global symmetry.",
        "positive": "Axial Vector Form Factors of the Nucleon from Lattice QCD: We present results for the form factors of the isovector axial vector current\nin the nucleon state using large scale simulations of lattice QCD. The\ncalculations were done using eight ensembles of gauge configurations generated\nby the MILC collaboration using the HISQ action with 2+1+1 dynamical flavors.\nThese ensembles span three lattice spacings $a \\approx 0.06, 0.09$ and $0.12$\nfm and light-quark masses corresponding to the pion masses $M_\\pi \\approx 135,\n225$ and $310$ MeV. High-statistics estimates allow us to quantify systematic\nuncertainties in the extraction of $G_A(Q^2)$ and the induced pseudoscalar form\nfactor $\\tilde{G}_P(Q^2)$. We perform a simultaneous extrapolation in the\nlattice spacing, lattice volume and light-quark masses of the axial charge\nradius $r_A$ data to obtain physical estimates. Using the dipole ansatz to fit\nthe $Q^2$ behavior we obtain $r_A|_{\\rm dipole} = 0.49(3)$ fm, which\ncorresponds to ${\\cal M}_A = 1.39(9)$ GeV, and is consistent with ${\\cal M}_A =\n1.35(17)$ GeV obtained by the miniBooNE collaboration. The estimate obtained\nusing the $z$-expansion is $r_A|_{z-{\\rm expansion}} = 0.46(6)$ fm, and the\ncombined result is $r_A|_{\\rm combined} = 0.48(4)$ fm. Analysis of the induced\npseudoscalar form factor $\\tilde{G}_P(Q^2)$ yields low estimates for $g_P^\\ast$\nand $g_{\\pi {\\rm NN}}$ compared to their phenomenological values. To understand\nthese, we analyze the partially conserved axial current (PCAC) relation by also\ncalculating the pseudoscalar form factor. We find that these low values are due\nto large deviations in the PCAC relation between the three form factors and\nfrom the pion-pole dominance hypothesis."
    },
    {
        "anchor": "HQET form factors for $B_s\\to K\\ell\u03bd$ decays beyond leading order: We compute semi-leptonic $B_s$ decay form factors using Heavy Quark Effective\nTheory on the lattice. To obtain good control of the $1/m_b$ expansion, one has\nto take into account not only the leading static order but also the terms\narising at $O(1/m_b)$: kinetic, spin and current insertions. We show results\nfor these terms calculated through the ratio method, using our prior results\nfor the static order. After combining them with non-perturbative HQET\nparameters they can be continuum-extrapolated to give the QCD form factor\ncorrect up to $O(1/m_b^2)$ corrections and without $O(\\alpha_s(m_b)^n)$\ncorrections.",
        "positive": "The quenched generating functional for hadronic weak interactions: The ultraviolet behaviour of the generating functional for hadronic weak\ninteractions with $|\\Delta S| =1, 2$ is investigated to one loop for a generic\nnumber of flavours and in the quenched approximation. New quenched chiral\nlogarithms generated by the weak interactions can be accounted for via a\nredefinition of the weak mass term in the $\\Delta S=\\pm 1$ weak effective\nLagrangian at leading order. Finally, we illustrate how chiral logarithms are\nmodified by the quenched approximation in $K\\to\\pi\\pi$ matrix elements with\n$\\Delta I=1/2$ and 3/2."
    },
    {
        "anchor": "Electromagnetic structure of charmed baryons in Lattice QCD: As a continuation of our recent work on the electromagnetic properties of the\ndoubly charmed $\\Xi_{cc}$ baryon, we compute the charge radii and the magnetic\nmoments of the singly charmed $\\Sigma_c$, $\\Omega_c$ and the doubly charmed\n$\\Omega_{cc}$ baryons in 2+1 flavor Lattice QCD. In general, the charmed\nbaryons are found to be compact as compared to the proton. The charm quark acts\nto decrease the size of the baryons to smaller values. We discuss the mechanism\nbehind the dependence of the charge radii on the light valence- and sea-quark\nmasses. The magnetic moments are found to be almost stable with respect to\nchanging quark mass. We investigate the individual quark sector contributions\nto the charge radii and the magnetic moments. The magnetic moments of the\nsingly charmed baryons are found to be dominantly determined by the light quark\nand the role of the charm quark is significantly enhanced for the doubly\ncharmed baryons.",
        "positive": "Abelian Projection without Ambiguities: Laplacian Abelian Projection is discussed. This term refers to the use of a\nnew (``Laplacian'') gauge fixing prescription for implementing the Abelian\nProjection of QCD. The gauge condition is based on the lowest-lying eigenvector\nof the covariant Laplacian operator in the adjoint representation.\n  This Laplacian gauge fixing procedure is free of the ambiguities which plague\nlattice simulations which work with the popular Maximally Abelian Gauge.\nFurthermore, Laplacian gauge fixed configurations enjoy a natural kind of\nsmoothness. These two properties are crucial for a reliable determination of\nphysical quantities using the Abelian Projection.\n  We also examine a new, Higgs-field-like observable which emerges as a\nby-product of the method. This quantity can be used to identify magnetic\nmonopoles in a way independent of the traditional prescription. It is argued\nthat physically relevant magnetic monopoles are accomodated well by the\nLaplacian method, while they are suppressed (too) strongly in Maximally Abelian\nGauge.\n  Finally, first evidence of abelian dominance in the Laplacian Abelian\nProjection is presented."
    },
    {
        "anchor": "Density distributions in the $B$ meson: We report on a two-flavor lattice QCD study of the axial, charge and matter\ndistributions of the $B$ meson and its first radial excitation. As our\nframework is the static limit of Heavy Quark Effective Theory (HQET), taking\ntheir Fourier transform gives access to several form factors at the kinematical\npoint $q^2=0$. Moreover they provide some useful information on the nature of\nan excited state, i.e. a radial excitation of a quark-antiquark bound state or\na multihadron state.",
        "positive": "Gauge field topology and the hadron spectrum: Topologically non-trivial gauge field configurations are an interesting\naspect of non-abelian gauge theories. These become particularly important upon\nquantizing the theory, especially through their effect on the pseudo-scalar\nspectrum. These effects are closely tied to chiral anomalies and the\npossibility of CP violation in the strong interactions."
    },
    {
        "anchor": "Ghost-gluon coupling, power corrections and $\u039b_{\\bar{\\rm MS}}$\n  from lattice QCD with a dynamical charm: This paper is a first report on the determination of $\\Lambda_{\\msbar}$ from\nlattice simulations with 2+1+1 twisted-mass dynamical flavours {\\it via} the\ncomputation of the ghost-gluon coupling renormalized in the MOM Taylor scheme.\nWe show this approach allows a very good control of the lattice artefacts and\nconfirm the picture from previous works with quenched and ${\\rm N}_f$=2\ntwisted-mass field configurations which prove the necessity to include\nnon-perturbative power corrections in the description of the running. We\nprovide with an estimate of $\\Lambda_{\\msbar}$ in very good agreement with\nexperimental results. To our knowledge it is the first calculation with a\ndynamical charm quark which makes the running up to $\\alpha_s(M_Z)$ much safer.",
        "positive": "Isospin-0 $\u03c0\u03c0$ scattering from twisted mass lattice QCD: We present results for the isospin-0 $\\pi\\pi$ s-wave scattering length\ncalculated in twisted mass lattice QCD. We use three $N_f = 2$ ensembles with\nunitary pion mass at its physical value, 240~MeV and 330~MeV respectively. We\nalso use a large set of $N_f = 2 + 1 +1$ ensembles with unitary pion masses\nvarying in the range of 230~MeV - 510~MeV at three different values of the\nlattice spacing. A mixed action approach with the Osterwalder-Seiler action in\nthe valence sector is adopted to circumvent the complications arising from\nisospin symmetry breaking of the twisted mass quark action. Due to the\nrelatively large lattice artefacts in the $N_f = 2 + 1 +1$ ensembles, we do not\npresent the scattering lengths for these ensembles. Instead, taking the\nadvantage of the many different pion masses of these ensembles, we\nqualitatively discuss the pion mass dependence of the scattering properties of\nthis channel based on the results from the $N_f = 2 + 1 +1$ ensembles. The\nscattering length is computed for the $N_f = 2$ ensembles and the chiral\nextrapolation is performed. At the physical pion mass, our result $M_\\pi\na^\\mathrm{I=0}_0 = 0.198(9)(6)$ agrees reasonably well with various\nexperimental measurements and theoretical predictions."
    },
    {
        "anchor": "The glueball spectrum from novel improved actions: Results for the inter-quark potential and low-lying SU(3) glueball spectrum\nfrom simulations using a new improved action are presented. The action,\nsuitable for highly anisotropic lattices, contains a two-plaquette term\ncoupling with a negative coefficient as well as incorporating Symanzik\nimprovement.",
        "positive": "Infrared physics of the 3D SU(2) adjoint Higgs model at the crossover\n  transition: We study the crossover phase transition of the SU(2) Georgi-Glashow model in\nthree dimensions. In this model, a confining condensate of topological 't\nHooft-Polyakov monopoles exists in the Higgs regime. We use lattice Monte Carlo\nsimulations to study the monopole gas across a crossover transition, and\ndemonstrate that gradient flow can be used to renormalize the otherwise\ndivergent monopole number density. The condensation of the monopoles means that\nthe theory admits also a massive photon-like excitation. We show that the\nrenormalized monopole number density is approximately proportional to the\nsquare of the photon mass, in agreement with semiclassical results. Our results\ngive insight into behaviour of the Higgs regime near crossover, which has\nboarder implications for beyond the Standard Model theories containing adjoint\nscalar fields."
    },
    {
        "anchor": "Dark matter Search and the Scalar Quark Contents of the Nucleon: We present lattice QCD simulation results from the European Twisted Mass\nCollaboration (ETMC) for the light, strange and charm quark contents of the\nnucleon. These quantities are important ingredients to estimate the\ncross-section for the detection of WIMPs as Dark Matter candidates. By\nemploying a particular lattice QCD formulation, i.e. twisted mass fermions,\naccurate results of the light and strange scalar contents of the nucleon can be\nobtained. In addition, we provide a bound for the charm quark content of the\nnucleon.",
        "positive": "Exploring a hidden symmetry with electrically charged quarks: It is usual to study confinement via quantum chromodynamics (QCD) alone. The\ndeconfinement transition of the pure gauge theory (i.e. with static quarks) is\nthen characterized by the breaking of center symmetry. Center vortices offer an\nintuitive and quantitative description of the transition. Dynamical quarks\nexplicitly break center symmetry, and the phase transition becomes a crossover.\nHowever, it may be misleading to study QCD in isolation. Quarks also carry\nfractional electric charge. This bestows the Standard Model with a global\ncenter symmetry that combines color center phases with an appropriate\nelectromagnetic phase. Is this symmetry relevant to confinement? We begin our\ninvestigation by studying a 2-color model of QCD with half-integer electrically\ncharged quarks."
    },
    {
        "anchor": "Decay Constants of Pseudoscalar Mesons to Two Loops in Three-Flavor\n  Partially Quenched $\u03c7$PT: This paper presents a first study of the decay constants of the charged, or\nflavor-off-diagonal, pseudoscalar mesons to two loops for three flavors of sea\nquarks, in Partially Quenched Chiral Perturbation Theory (PQ$\\chi$PT). Explicit\nanalytical expressions up to ${\\cal O}(p^6)$ in the momentum expansion are\ngiven. The calculations have been performed within the supersymmetric\nformulation of PQ$\\chi$PT. We also present some numerical results to indicate\nthe size of the corrections.",
        "positive": "Creutz Fermions on an Orthogonal Lattice: In a recent paper, Creutz has given a new action describing two species of\nDirac fermions with exact chiral symmetry on the lattice. This action depends\non a parameter which may be fixed at a certain value in order to get the right\ncontinuum limit. In this letter, we elaborate more on this idea and present an\naction which is free of any other parameter except the fermion mass."
    },
    {
        "anchor": "Lattice measurement of $B_{B_s}$ with a chiral light quark action: The computation on the lattice of the bag parameter $B_{B_s}$ associated to\nthe $B_s - \\bar{B_s}$ mixing amplitude in the Standard Model is presented. The\nestimation has been made by combining the static limit of HQET and the\nNeuberger light quark action which preserves the chiral symmetry on the\nlattice. We find $B^{\\bar{MS}}{stat}}_{B_s}(m_b)=0.92(3)$.",
        "positive": "An estimate of the eta and eta-prime meson masses in Nf=2+1 lattice QCD: Masses of the eta and eta-prime mesons are estimated in Nf=2+1 lattice QCD\nwith the non-perturbatively O(a) improved Wilson quark action and the Iwasaki\nRG-improved gluon action, using CP-PACS/JLQCD configurations on a 16^3 x 32\nlattice at beta=1.83 (lattice spacing is 0.122 fm). We apply a stochastic noise\nestimator technique combined with smearing method to evaluate correlators among\nflavor SU(2) singlet pseudoscalar operators and strange pseudoscalar operators\nfor 10 combinations of up/down and strange quark masses. The correlator matrix\nis then diagonalized to identify signals for mass eigenstates. Masses of the\nground state and the first excited state extrapolated to the physical point are\nm_eta= 0.545(16) GeV and m_eta-prime= 0.871(46) GeV, being close to the\nexperimental values of the eta and eta-prime masses."
    },
    {
        "anchor": "Finite-volume effects and the electromagnetic contributions to kaon and\n  pion masses: We report on the MILC Collaboration calculation of electromagnetic effects on\nlight pseudoscalar mesons. The simulations employ asqtad staggered dynamical\nquarks in QCD plus quenched photons, with lattice spacings varying from 0.12 to\n0.06 fm. Finite volume corrections for the MILC realization of lattice\nelectrodynamics have been calculated in chiral perturbation theory and applied\nto the lattice data. These corrections differ from those calculated by Hayakawa\nand Uno because our treatment of zero modes differs from theirs. Updated\nresults for the corrections to \"Dashen's theorem\" are presented.",
        "positive": "Prediction and compression of lattice QCD data using machine learning\n  algorithms on quantum annealer: We present regression and compression algorithms for lattice QCD data\nutilizing the efficient binary optimization ability of quantum annealers. In\nthe regression algorithm, we encode the correlation between the input and\noutput variables into a sparse coding machine learning algorithm. The trained\ncorrelation pattern is used to predict lattice QCD observables of unseen\nlattice configurations from other observables measured on the lattice. In the\ncompression algorithm, we define a mapping from lattice QCD data of\nfloating-point numbers to the binary coefficients that closely reconstruct the\ninput data from a set of basis vectors. Since the reconstruction is not exact,\nthe mapping defines a lossy compression, but, a reasonably small number of\nbinary coefficients are able to reconstruct the input vector of lattice QCD\ndata with the reconstruction error much smaller than the statistical\nfluctuation. In both applications, we use D-Wave quantum annealers to solve the\nNP-hard binary optimization problems of the machine learning algorithms."
    },
    {
        "anchor": "HISQ action in dynamical simulations: We report on recent progress in employing the Highly Improved Staggered Quark\n(HISQ) action introduced by the HPQCD/UKQCD collaboration in simulations with\ndynamical fermions. The HISQ action is an order $a^2$ Symanzik-improved action\nwith further suppressed taste symmetry violations. The improvement in taste\nsymmetry is achieved by introducing Fat7 smearing of the original gauge links\nand reunitarization (projection to an element of U(3) or SU(3)) followed by\nAsq-type smearing. Major challenges for calculating the fermion force are\nrelated to the reunitarization step. We present a preliminary study of the HISQ\naction on two 2+1+1 flavor ensembles with the lattice spacing roughly\nequivalent to the MILC asqtad a=0.125 and 0.09 fm ensembles.",
        "positive": "Static quark-antiquark potential in the quark-gluon plasma from lattice\n  QCD: We present a state-of-the-art determination of the complex valued static\nquark-antiquark potential at phenomenologically relevant temperatures around\nthe deconfinement phase transition. Its values are obtained from\nnon-perturbative lattice QCD simulations using spectral functions extracted via\na novel Bayesian inference prescription. We find that the real part, both in a\ngluonic medium as well as in realistic QCD with light $u$, $d$ and $s$ quarks,\nlies close to the color singlet free energies in Coulomb gauge and shows Debye\nscreening above the (pseudo) critical temperature $T_c$. The imaginary part is\nestimated in the gluonic medium, where we find that it is of the same order of\nmagnitude as in hard-thermal loop resummed perturbation theory in the\ndeconfined phase."
    },
    {
        "anchor": "Excited $D$ and $D_{s}$ meson spectroscopy from lattice QCD: We present highly excited spectra of charm-light and charm-strange mesons\nfrom dynamical lattice QCD. Our calculations are performed on anisotropic\n$N_{f} = 2+1$ dynamical ensembles generated by the Hadron Spectrum\nCollaboration. The use of novel techniques and a large basis of interpolating\noperators have allowed us to extract these spectra to a high degree of\nstatistical precision, extract states of high spin and observe candidate hybrid\nmesons. We interpret and discuss our results in light of the current\nexperimental situation.",
        "positive": "Chiral behavior of baryon magnetic moments: The utility of chiral effective field theory, constructed in a manner in\nwhich loop contributions are suppressed as one moves outside the power-counting\nregime, is explored for baryon magnetic moments. Opportunities for the study of\nsignificant chiral curvature in valence and full QCD and the nontrivial\nbehavior of strange- and light-quark contributions to the magnetic moment of\nthe Lambda baryon are highlighted."
    },
    {
        "anchor": "Meson decay constants from Nf=2 clover fermions: We present recent results for meson decay constants calculated on\nconfigurations with two flavours of O(a)-improved Wilson fermions.\nNon-perturbative renormalisation is applied and quark mass dependencies as well\nas finite volume and discretisation effects are investigated. In this work we\nalso present a computation of the coupling of the light vector mesons to the\ntensor current using dynamical fermions.",
        "positive": "Finite Temperature QCD on Anisotropic Lattices: We present results for mesonic propagators in temporal and spatial direction\nand for topological properties at T below and above the deconfining transition\nin quenched QCD. We use anisotropic lattices and Wilson fermions."
    },
    {
        "anchor": "Center flux correlation in SU(2) Yang-Mills theory: By using the method of center projection the center vortex part of the gauge\nfield is isolated and its propagator is evaluated in the center Landau gauge,\nwhich minimizes the open 3-dimensional Dirac volumes of non-trivial center\nlinks bounded by the closed 2-dimensional center vortex surfaces. The center\nfield propagator is found to dominate the gluon propagator (in Landau gauge) in\nthe low momentum regime and to give rise to an OPE correction to the latter of\n${\\sqrt{\\sigma}}/{p^3}$.The screening mass of the center vortex field vanishes\nabove the critical temperature of the deconfinement phase transition, which\nnaturally explains the second order nature of this transition consistent with\nthe vortex picture. Finally, the ghost propagator of maximal center gauge is\nfound to be infrared finite and thus shows that the coset fields play no role\nfor confinement.",
        "positive": "Exploration of sea quark effects in two-flavor QCD with the\n  O(a)-improved Wilson quark action: We explore sea quark effects in the light hadron mass spectrum in a\nsimulation of two-flavor QCD using the nonperturbatively O(a)-improved Wilson\nfermion action. In order to identify finite-size effects, light meson masses\nare measured on 12^3x48, 16^3x48 and 20^3x48 lattices with a~0.1 fm. On the\nlargest lattice, where the finite-size effect is negligible, we find a\nsignificant increase of the strange vector meson mass compared to the quenched\napproximation. We also investigate the quark mass dependence of pseudoscalar\nmeson masses and decay constants and test the consistency with (partially\nquenched) chiral perturbation theory."
    },
    {
        "anchor": "Central Dominance and the Confinement Mechanism in Gluodynamics: New topological objects, which we call center monopoles, naturally arise in\nthe Maximal Center Projection of SU(3) gluodynamics. The condensate of the\ncenter monopoles is the order parameter of the theory.",
        "positive": "Twisted mass quarks and the phase structure of lattice QCD: The phase structure of zero temperature twisted mass lattice QCD is\ninvestigated. We find strong metastabilities in the plaquette observable when\nthe untwisted quark mass assumes positive or negative values. We provide\ninterpretations of this phenomenon in terms of chiral symmetry breaking and the\neffective potential model of Sharpe and Singleton."
    },
    {
        "anchor": "Polyakov loop in different representations of SU(3) at finite\n  temperature: We investigate the Polyakov loop in different representations of SU(3) in\npure gauge at finite $T$. We discuss Casimir scaling for the Polyakov loop in\nthe deconfined phase and test and generalize the renormalization procedure for\nthe Polyakov loop from \\cite{Kaczmarek:2002mc} to arbitrary representations. In\nthe confined phase we extract the renormalized adjoint Polyakov loop, which is\nfinite in the thermodynamic limit. For our numerical calculations we used the\ntree-level improved Symanzik action on $32^3\\times 4,6,8$ lattices.",
        "positive": "Dynamic Critical Behavior of the Swendsen-Wang Algorithm: The\n  Two-Dimensional 3-State Potts Model Revisited: We have performed a high-precision Monte Carlo study of the dynamic critical\nbehavior of the Swendsen-Wang algorithm for the two-dimensional 3-state Potts\nmodel. We find that the Li-Sokal bound ($\\tau_{int,E} \\geq const \\times C_H$)\nis almost but not quite sharp. The ratio $\\tau_{int,E} / C_H$ seems to diverge\neither as a small power ($\\approx 0.08$) or as a logarithm."
    },
    {
        "anchor": "Heavy hadrons on $N_f=2$ and $2+1$ improved clover-Wilson lattices: We present the masses of singly ($B$, $B_s$, $\\Lambda_b$, $\\Sigma_b$, etc.),\ndoubly ($B_c$, $\\eta_b$, $\\Upsilon$, $\\Xi_{bc}$, $\\Xi_{bb}$, etc.), and triply\n($\\Omega_{bcc}$, $\\Omega_{bbc}$, $\\Omega_{bbb}$, etc.) heavy hadrons arising\nfrom (QCDSF-UKQCD) lattices with improved clover-Wilson light quarks. For the\nbottom quark, we use an $O(a,v^4)$-improved version of lattice NRQCD. Part of\nthe bottomonia spectrum is used to provide an alternative scale and to\ndetermine the physical quark mass and radiative corrections used in the\nheavy-quark action. Results for spin splittings, opposite parities, and, in\nsome cases, excited states are presented. Higher lying states and baryons with\ntwo light quarks appear to be especially affected by the relatively small\nvolumes of this (initially) initial study. This and other systematics are\nbriefly discussed.",
        "positive": "Relating Quark Confinement and Chiral Symmetry Breaking in QCD: We study the relation between quark confinement and chiral symmetry breaking\nin QCD. Using lattice QCD formalism, we analytically express the various\n\"confinement indicators\", such as the Polyakov loop, its fluctuations, the\nWilson loop, the inter-quark potential and the string tension, in terms of the\nDirac eigenmodes. In the Dirac spectral representation, there appears a power\nof the Dirac eigenvalue $\\lambda_n$ such as $\\lambda_n^{N_t-1}$, which behaves\nas a reduction factor for small $\\lambda_n$. Consequently, since this reduction\nfactor cannot be cancelled, the low-lying Dirac eigenmodes give negligibly\nsmall contribution to the confinement quantities,while they are essential for\nchiral symmetry breaking. These relations indicate no direct, one-to-one\ncorrespondence between confinement and chiral symmetry breaking in QCD. In\nother words, there is some independence of quark confinement from chiral\nsymmetry breaking, which can generally lead to different transition\ntemperatures/densities for deconfinement and chiral restoration. We also\ninvestigate the Polyakov loop in terms of the eigenmodes of the Wilson, the\nclover and the domain-wall fermion kernels, respectively, and find the similar\nresults. The independence of quark confinement from chiral symmetry breaking\nseems to be natural, because confinement is realized independently of quark\nmasses and heavy quarks are also confined even without the chiral symmetry."
    },
    {
        "anchor": "Parity doubling of nucleons, Delta and Omega baryons across the\n  deconfinement phase transition: In this work we analyse positive- and negative-parity channels for the\nnucleon (spin $1/2$ octet), $\\Delta$ and $\\Omega$ baryons (spin $3/2$ decuplet)\nusing lattice QCD. In Nature, at zero temperature, chiral symmetry is\nspontaneously broken, causing positive- and negative-parity ground states to\nhave different masses. However, chiral symmetry is expected to be restored (for\nmassless quarks) around the crossover temperature, implying that the two\nopposite parity channels should become degenerate. Here we study what happens\nin a temperature range which includes both the hadronic and the quark gluon\nplasma (QGP) phase. By analysing the correlation and spectral functions via\nexponential fits and the Maximum Entropy Method respectively, we have found\nparity doubling for the nucleon and $\\Delta$ baryon channels in the QGP phase.\nFor the $\\Omega$ baryon we see a clear signal of parity doubling at the\ncrossover temperature, which is however not complete, due to the nonzero\nstrange quark mass. Moreover, in-medium effects in the hadronic phase are\nevident for all three baryons, in particular for the negative-parity ground\nstates. This might have implications for the hadron resonance gas model. In\nthis work we used the FASTSUM anisotropic $N_f = 2 + 1$ ensembles.",
        "positive": "Various Abelian Projections of $SU(2)$ Lattice Gluodynamics and\n  Aharonov-Bohm Effect in the Field Theory: We show that in general abelian projection of lattice gluodynamics it is not\nonly monopoles but also strings are present. Both these topological excitations\nmay be responsible for the confinement of color. We illustrate our ideas by\nsome explicit results in the Abelian Higgs model with the Villain action."
    },
    {
        "anchor": "Accelerating Wilson Fermion Matrix Inversions by Means of the Stabilized\n  Biconjugate Gradient Algorithm: The stabilized biconjugate gradient algorithm BiCGStab recently presented by\nvan der Vorst is applied to the inversion of the lattice fermion operator in\nthe Wilson formulation of lattice Quantum Chromodynamics. Its computational\nefficiency is tested in a comparative study against the conjugate gradient and\nminimal residual methods. Both for quenched gauge configurations at beta= 6.0\nand gauge configurations with dynamical fermions at beta=5.4, we find BiCGStab\nto be superior to the other methods. BiCGStab turns out to be particularly\nuseful in the chiral regime of small quark masses.",
        "positive": "$K\\to(\u03c0\u03c0)_{I=2}$ decays and twisted boundary conditions: We propose a new method to evaluate the Lellouch-L\\\"uscher factor which\nrelates the $\\Delta I=3/2$ $K\\to\\pi\\pi$ matrix elements computed on a finite\nlattice to the physical (infinite-volume) decay amplitudes. The method relies\non the use of partially twisted boundary conditions, which allow the s-wave\n$\\pi\\pi$ phase shift to be computed as an almost continuous function of the\ncentre-of-mass relative momentum and hence for its derivative to be evaluated.\nWe successfully demonstrate the feasibility of the technique in an exploratory\ncomputation."
    },
    {
        "anchor": "Prepotential formulation of SU(3) lattice gauge theory: The SU(3) lattice gauge theory is reformulated in terms of SU(3) prepotential\nharmonic oscillators. This reformulation has enlarged $SU(3)\\otimes U(1)\n\\otimes U(1)$ gauge invariance under which the prepotential operators transform\nlike matter fields. The Hilbert space of SU(3) lattice gauge theory is shown to\nbe equivalent to the Hilbert space of the prepotential formulation satisfying\ncertain color invariant Sp(2,R) constraints. The SU(3) irreducible prepotential\noperators which solve these Sp(2,R) constraints are used to construct SU(3)\ngauge invariant Hilbert spaces at every lattice site in terms of SU(3) gauge\ninvariant vertex operators. The electric fields and the link operators are\nreconstructed in terms of these SU(3) irreducible prepotential operators. We\nshow that all the SU(3) Mandelstam constraints become local and take very\nsimple form within this approach. We also discuss the construction of all\npossible linearly independent SU(3) loop states which solve the Mandelstam\nconstraints. The techniques can be easily generalized to SU(N).",
        "positive": "Gauge Equivariant Neural Networks for 2+1D U(1) Gauge Theory Simulations\n  in Hamiltonian Formulation: Gauge Theory plays a crucial role in many areas in science, including high\nenergy physics, condensed matter physics and quantum information science. In\nquantum simulations of lattice gauge theory, an important step is to construct\na wave function that obeys gauge symmetry. In this paper, we have developed\ngauge equivariant neural network wave function techniques for simulating\ncontinuous-variable quantum lattice gauge theories in the Hamiltonian\nformulation. We have applied the gauge equivariant neural network approach to\nfind the ground state of 2+1-dimensional lattice gauge theory with U(1) gauge\ngroup using variational Monte Carlo. We have benchmarked our approach against\nthe state-of-the-art complex Gaussian wave functions, demonstrating improved\nperformance in the strong coupling regime and comparable results in the weak\ncoupling regime."
    },
    {
        "anchor": "Dibaryon with highest charm number near unitarity from lattice QCD: A pair of triply charmed baryons, $\\Omega_{ccc}\\Omega_{ccc}$, is studied as\nan ideal dibaryon system by (2+1)-flavor lattice QCD with nearly physical\nlight-quark masses and the relativistic heavy quark action with the physical\ncharm quark mass. The spatial baryon-baryon correlation is related to their\nscattering parameters on the basis of the HAL QCD method. The\n$\\Omega_{ccc}\\Omega_{ccc}$ in the ${^1S_0}$ channel taking into account the\nCoulomb repulsion with the charge form factor of $\\Omega_{ccc}$ leads to the\nscattering length $a^{\\rm C}_0\\simeq -19~\\text{fm}$ and the effective range\n$r^{\\rm C}_{\\mathrm{eff}}\\simeq 0.45~\\text{fm}$. The ratio $r^{\\rm\nC}_{\\mathrm{eff}}/a^{\\rm C}_0 \\simeq -0.024$, whose magnitude is considerably\nsmaller than that of the dineutron ($-0.149$), indicates that\n$\\Omega_{ccc}\\Omega_{ccc}$ is located in the unitary regime.",
        "positive": "Thermodynamics of Four-Flavour QCD with Improved Staggered Fermions: We have calculated the pressure and energy density in four-flavour QCD using\nimproved fermion and gauge actions. We observe a strong reduction of finite\ncut-off effects in the high temperature regime, similar to what has been noted\nbefore for the SU(3) gauge theory. Calculations have been performed on\n$16^3\\times 4$ and 16^4 lattices for two values of the quark mass, $ma = 0.05$\nand 0.1. A calculation of the string tension at zero temperature yields a\ncritical temperature $T_c/\\sqrt{\\sigma} = 0.407 \\pm 0.010$ for the smaller\nquark mass value."
    },
    {
        "anchor": "Comments on staggered fermions / Panel discussion: The rooting procedure commonly used with staggered fermions does not\ncorrectly treat non-perturbative effects associated with gauge field topology.\nIn practice these effects are small for the physics of flavor non-singlet\nparticles. However large uncontrolled systematic errors are expected for flavor\nsinglet issues, such as the mass of the eta prime meson. While the relative\nspeed of the algorithm in large scale simulations may justify its use, the\nmethod is an approximation and should not be promoted as a first principles\napproach to the strong interactions.",
        "positive": "Nucleon excited states on the lattice: We study the pion-nucleon system in s-wave in the framework of lattice QCD in\norder to gain new information on the nucleon excited states. We perform\nsimulations for $n_f =2$ mass degenerate light quarks at a pion mass of 266\nMeV. The results show that including the two-particle states drastically\nchanges the energy levels. The variational analysis and the distillation\napproach play an important role in the extraction of the energy levels. The\nphase shift analysis allows to extract information on the resonance nature of\nthe observed states."
    },
    {
        "anchor": "Nucleon strange quark content from N_f=2+1 lattice QCD with exact chiral\n  symmetry: We calculate the strange quark content of the nucleon in 2+1-flavor lattice\nQCD. Chirally symmetric overlap fermion formulation is used to avoid the\ncontamination from up and down quark contents due to an operator mixing between\nstrange and light scalar operators, \\bar{s}s and \\bar{u}u+\\bar{d}d. At a\nlattice spacing a=0.112(1) fm, we perform calculations at four values of\ndegenerate up and down quark masses, which cover a range of the pion mass M_pi\n\\simeq 300-540 MeV. We employ two different methods: one is a direct method\nwhere we calculate the strange quark content by directly inserting the strange\nscalar operator. The other is an indirect method where the quark content is\nextracted from a derivative of the nucleon mass in terms of the strange quark\nmass. With these two methods we obtain consistent results with each other. Our\nbest estimate f_{T_s}=0.009(15)(16) is in good agreement with our previous\nstudies in two-flavor QCD.",
        "positive": "Magnetic Monopoles, Center Vortices and Topology of Gauge Fields: The topological properties of magnetic monopoles and center vortices arising,\nrespectively, in Abelian and center gauges are studied in continuum Yang-Mills\nTheory. For this purpose the continuum analog of the maximum center gauge is\nconstructed."
    },
    {
        "anchor": "Status update: $\u03c0^0\\to \u03b3^\\ast \u03b3^\\ast$ transition form factor\n  on CLS ensembles: In this report we present the status of the Mainz group's lattice QCD\ncalculation of the pion transition form factor, which describes the interaction\nof an on-shell pion with two off-shell photons. This form factor is the main\ningredient in the calculation of the pion-pole contribution to hadronic\nlight-by-light scattering in the muon $g-2$. We use the $N_f = 2 + 1$ CLS gauge\nensembles, and we update our previous work by including a physical pion mass\nensemble (E250). We compute the transition form factor in a moving frame as\nwell as in the pion rest frame in order to have access to a wider range of\nphoton virtualities. In addition to the quark-line connected correlator we also\ncompute the quark-line disconnected diagrams that contribute to the form\nfactor. At the final stage of the analysis, the result on E250 will be combined\nwith the previous work published in 2019 to extrapolate the form factor to the\ncontinuum and to physical quark masses.",
        "positive": "The derivation of the dual superconductor theory from the Maximal Center\n  projected SU(3) - gluodynamics: We consider the Center projected SU(3) gluodynamics and rewrite it as a dual\nsuperconductor theory. The center monopole field plays the role of Higgs field\nin the dual superconductor theory.\n  The center monopole creation operator is constructed."
    },
    {
        "anchor": "Modified Block BiCGSTAB for Lattice QCD: We present results for application of block BiCGSTAB algorithm modified by\nthe QR decomposition and the SAP preconditioner to the Wilson-Dirac equation\nwith multiple right-hand sides in lattice QCD on a $32^3 \\times 64$ lattice at\nalmost physical quark masses. The QR decomposition improves convergence\nbehaviors in the block BiCGSTAB algorithm suppressing deviation between true\nresidual and recursive one. The SAP preconditioner applied to the\ndomain-decomposed lattice helps us minimize communication overhead. We find\nremarkable cost reduction thanks to cache tuning and reduction of number of\niterations.",
        "positive": "Ratios of the hadronic contributions to the lepton $g-2$ from Lattice\n  QCD+QED simulations: The ratios among the leading-order (LO) hadronic vacuum polarization (HVP)\ncontributions to the anomalous magnetic moments of electron, muon and\ntau-lepton, $a_{\\ell=e,\\mu \\tau}^{HVP,LO}$, are computed using lattice QCD+QED\nsimulations. The results include the effects at order $O(\\alpha_{em}^2)$ as\nwell as the electromagnetic and strong isospin-breaking corrections at orders\n$O(\\alpha_{em}^3)$ and $O(\\alpha_{em}^2(m_u-m_d))$, respectively, where\n$(m_u-m_d)$ is the $u$- and $d$-quark mass difference. We employ the gauge\nconfigurations generated by the Extended Twisted Mass Collaboration with\n$N_f=2+1+1$ dynamical quarks at three values of the lattice spacing ($a \\simeq\n0.062, 0.082, 0.089$ fm) with pion masses in the range 210 - 450 MeV. We show\nthat in the case of the electron-muon ratio the hadronic uncertainties in the\nnumerator and in the denominator largely cancel out, while in the cases of the\nelectron-tau and muon-tau ratios such a cancellation does not occur. For the\nelectron-muon ratio we get $R_{e/\\mu } \\equiv (m_\\mu/m_e)^2 (a_e^{HVP,LO} /\na_\\mu^{HVP,LO}) = 1.1456~(83)$ with an uncertainty of $\\simeq 0.7 \\%$. Our\nresult, which represents an accurate Standard Model (SM) prediction, agrees\nvery well with the estimate obtained using the results of dispersive analyses\nof the experimental $e^+ e^- \\to$ hadrons data. Instead, it differs by $\\simeq\n2.7$ standard deviations from the value expected from present electron and muon\n(g - 2) experiments after subtraction of the current estimates of the QED,\nelectro-weak, hadronic light-by-light and higher-order HVP contributions,\nnamely $R_{e/\\mu} = 0.575~(213)$. An improvement of the precision of both the\nexperiment and the QED contribution to the electron (g - 2) by a factor of\n$\\simeq 2$ could be sufficient to reach a tension with our SM value of the\nratio $R_{e/\\mu }$ at a significance level of $\\simeq 5$ standard deviations."
    },
    {
        "anchor": "What is QFT? Resurgent trans-series, Lefschetz thimbles, and new exact\n  saddles: This is an introductory level review of recent applications of resurgent\ntrans-series and Picard-Lefschetz theory to quantum mechanics and quantum field\ntheory. Resurgence connects local perturbative data with global topological\nstructure. In quantum mechanical systems, this program provides a constructive\nrelation between different saddles. For example, in certain cases it has been\nshown that all information around the instanton saddle is encoded in\nperturbation theory around the perturbative saddle. In quantum field theory,\nsuch as sigma models compactified on a circle, neutral bions provide a\nsemi-classical interpretation of the elusive IR-renormalon, and fractional kink\ninstantons lead to the non-perturbatively induced gap, of order of the strong\nscale. In the path integral formulation of quantum mechanics, saddles must be\nfound by solving the holomorphic Newton's equation in the inverted\n(holomorphized) potential. Some saddles are complex, multi-valued, and even\nsingular, but of finite action, and their inclusion is strictly necessary to\nprevent inconsistencies. The multi-valued saddles enter either via resurgent\ncancellations, or their phase is tied with a hidden topological angle. We\nemphasize the importance of the destructive/constructive interference effects\nbetween equally dominant saddles in the Lefschetz thimble decomposition. This\nis especially important in the context of the sign problem.",
        "positive": "Meson Form-factors and Wave-functions with Wilson fermions: Results for semi-leptonic form-factors for processes like $D \\to K l \\nu$ and\nthe Bethe-Salpeter amplitudes (BSA) for pion and rho mesons are presented. The\nform-factor data is consistent with previous calculations. We find that the\nlong distance fall-off of BSA for both $\\pi$ and $\\rho$ is very well fit by an\nexponential, but surprisingly the effective mass governing this fall-off is\nlighter than the pion's. Lastly, by studying the dependence of $\\rho$\npolarization on separation direction we show that there is a measureable $l=2$\nstate in addition to $l=0$ in the BSA for the rho. (Talk presented by R. Gupta\nat LATTICE92. Latex needs macro package espcrc2.sty)"
    },
    {
        "anchor": "Overview of lattice calculations of the $x$-dependence of PDFs, GPDs and\n  TMDs: For a long time, lattice QCD was unable to address the $x$-dependence of\npartonic distributions, direct access to which is impossible in Euclidean\nspacetime. Recent years have brought a breakthrough for such calculations when\nit was realized that partonic light-cone correlations can be accessed through\nspatial correlations computable on the lattice. Appropriately devised\nobservables can be factorized into physical PDFs via a perturbative procedure\ncalled matching, analogous to the standard factorization of experimental cross\nsections. In this short review, aimed at a broader high-energy and nuclear\nphysics community, we discuss the recent highlights of this research program.\nKey concepts are outlined, followed by a case study illustrating the typical\nstage of current lattice extractions and by a brief review of the most recent\nexplorations. We finalize with a number of messages for the prospects of\nlattice determinations of partonic structure.",
        "positive": "Topology of trace deformed Yang-Mills theory: In this paper we study, by means of numerical simulations, the topological\nproperties of $SU(3)$ and $SU(4)$ trace deformed Yang-Mills theory defined on $\n\\mathbb{R}^3\\times S^1$, in which center symmetry is recovered even at small\ncompactification radii. In particular, we compute the topological\nsuscpetibility $\\chi$ and the coefficient $b_2$ (related to the fourth cumulant\nof the topological charge distribution). We find that these observables\ncomputed in the deformed theory when center symmetry is recovered are\ncompatible with their values at zero temperature both for 3 and 4 colours"
    },
    {
        "anchor": "The behavior of the sextic coupling for the the three-dimensional\n  $\u03c6^4 $ theory: In this work we use the lattice regularization method to study the behavior\nof the six point renormalized coupling constant defined at zero momentum for\nthe three-dimensional $\\phi^4 $ theory in the intermediate and strong coupling\ndomain. The result is in good agreement with the corresponding study in the\nIsing limit.",
        "positive": "Chiral fermions on the lattice and index relations: Comparing recent lattice results on chiral fermions and old continuum results\nfor the index puzzling questions arise. To clarify this issue we start with a\ncritical reconsideration of the results on finite lattices. We then work out\nvarious aspects of the continuum limit. After determining bounds and norm\nconvergences we obtain the limit of the anomaly term. Collecting our results\nthe index relation of the quantized theory gets established. We then compare in\ndetail with the Atiyah-Singer theorem. Finally we analyze conventional\ncontinuum approaches."
    },
    {
        "anchor": "Update on $SU(2)$ with one adjoint Dirac flavor: We present an update of our ongoing study of the SU(2) gauge theory with one\nflavor of Dirac fermion in the adjoint representation. Compared to our previous\nresults we now have data at larger lattice volumes, smaller values of the\nfermion mass, and also larger values of $\\beta$. We present data for the\nspectrum of mesons, baryons, glueballs, and the hybrid fermion-glue state, as\nwell as new estimates of the mass anomalous dimension from both finite-size\nhyperscaling and the Dirac mode number, and discuss the implications of these\ndata for the presence or otherwise of chiral symmetry breaking in this theory.",
        "positive": "Vortex free energies in SO(3) and SU(2) lattice gauge theory: Lattice gauge theories with gauge groups SO(3) and SU(2) are compared. The\nfree energy of electric twist, an order parameter for the\nconfinement-deconfinement transition which does not rely on centre-symmetry\nbreaking, is measured in both theories. The results are used to calibrate the\nscale in SO(3)."
    },
    {
        "anchor": "Random Walks with Long-Range Self-Repulsion on Proper Time: We introduce a model of self-repelling random walks where the short-range\ninteraction between two elements of the chain decreases as a power of the\ndifference in proper time. Analytic results on the exponent $\\nu$ are obtained.\nThey are in good agreement with Monte Carlo simulations in two dimensions. A\nnumerical study of the scaling functions and of the efficiency of the algorithm\nis also presented.",
        "positive": "Application of tensor network method to two dimensional lattice\n  $\\mathcal{N}=1$ Wess-Zumino model: We study a tensor network formulation of the two dimensional lattice\n$\\mathcal{N}=1$ Wess-Zumino model with Wilson derivatives for both fermions and\nbosons. The tensor renormalization group allows us to compute the partition\nfunction without the sign problem, and basic ideas to obtain a tensor network\nfor both fermion and scalar boson systems were already given in previous works.\nIn addition to improving the methods, we have constructed a tensor network\nrepresentation of the model including the Yukawa-type interaction of Majorana\nfermions and real scalar bosons. We present some numerical results."
    },
    {
        "anchor": "Simulating twisted mass fermions at physical light, strange and charm\n  quark masses: We present the QCD simulation of the first gauge ensemble of two degenerate\nlight quarks, a strange and a charm quark with all quark masses tuned to their\nphysical values within the twisted mass fermion formulation. Results for the\npseudoscalar masses and decay constants confirm that the produced ensemble is\nindeed at the physical parameters of the theory. This conclusion is\ncorroborated by a complementary analysis in the baryon sector. We examine\ncutoff and isospin breaking effects and demonstrate that they are suppressed\nthrough the presence of a clover term in the action.",
        "positive": "Effects of partial quenching and staggered fermions on the scalar\n  correlator: We determine the mass of the lightest quark-antiquark scalar meson with I=1\nusing the simulation with two dynamical Domain Wall Fermions. The conventional\nexponential fit of the scalar correlator is justified in this case giving the\nmass 1.58 +/- 0.34 GeV. In general the scalar correlator receives also the\nbubble contribution, which is the intermediate state with two pseudoscalar\nmesons. This contribution is sizable at light quark masses and has to be\nincorporated in the fit of the scalar correlator in order to extract the scalar\nmeson mass. We provide predictions for the bubble contribution in Partially\nQuenched ChPT, Staggered ChPT and ChPT for Mixed quark actions. We find that\nthe bubble contribution is significantly affected by the unphysical\napproximations that are employed in simulations. It can render the negative\nsign and unphysical effective mass 2*Mpi in the scalar correlator with I=1."
    },
    {
        "anchor": "Applying Integrability to Gauge Theories: Lattice Yang-Mills theories in any dimension may be regarded as coupled\n1+1-dimensional integrable field theories. These integrable systems decouple at\nlarge center-of-mass energies, where the action becomes effectively\nanisotropic. This effective action is the high-energy center-of-mass limit of\nthe gauge theory. In 2+1 dimensions, the quark-antiquark potential and the mass\nspectrum can be calculated, using the exact 1+1-dimensional S-matrix and form\nfactors. The methods are quite similar to those applying integrability in\nstatistical and condensed-matter physics. The high-energy anisotropic action at\none loop in 3+1 dimensions has been found using a Wilsonian renormalization\nmethod. We briefly discuss the isotropic theory in 2+1 dimensions and the\nconnection with soft scattering in 3+1 dimensions.",
        "positive": "QCD phase diagram with 2-flavor lattice fermion formulations: We propose a new framework for investigating two-flavor lattice QCD with\nfinite temperature and density. We consider the Karsten-Wilczek fermion\nformulation, in which a species-dependent imaginary chemical potential term can\nreduce the number of species to two without losing chiral symmetry. This\nlattice discretization is useful for study on finite-($T$,$\\mu$) QCD since its\ndiscrete symmetries are appropriate for the case. To show its applicability, we\nstudy strong-coupling lattice QCD with temperature and chemical potential. We\nderive the effective potential of the scalar meson field and obtain a critical\nline of the chiral phase transition, which is qualitatively consistent with the\nphenomenologically expected phase diagram. We also discuss that $O(1/a)$\nrenormalization of imaginary chemical potential can be controlled by adjusting\na parameter of a dimension-3 counterterm."
    },
    {
        "anchor": "Chromoelectric and chromomagnetic fields for the static\n  gluon-quark-antiquark system: The chromoelectric and chromomagnetic fields, created by a static\ngluon-quark-antiquark system, are computed in the quenched approximation of\nlattice QCD, in a $24^3\\times 48$ lattice at $\\beta=6.2$. We study two\ngeometries, one with a U shape and another with an L shape. The degenerate case\nof the two gluon glueball is also studied. This is relevant to understand the\nmicroscopic structure of hadrons, in particular of hybrids. This also\ncontributes to understand confinement with flux tubes of the chromoelectric\nfield, and to discriminate between the models of fundamental or adjoint tubes.",
        "positive": "A physicist-friendly reformulation of the Atiyah-Patodi-Singer index (on\n  a lattice): The Atiyah-Singer index theorem on a closed manifold is well understood and\nappreciated in physics. On the other hand, the Atiyah-Patodi-Singer index,\nwhich is an extension to a manifold with boundary, is physicist-unfriendly, in\nthat it is formulated with a nonlocal boundary condition. Recently we proved\nthat the same index as APS is obtained from the domain-wall fermion Dirac\noperator. Our theorem indicates that the index can be expressed without any\nnonlocal conditions, in such a physicist-friendly way that application to the\nlattice gauge theory is straightforward. The domain-wall fermion provides a\nnatural mathematical foundation for understanding the bulk-edge correspondence\nof the anomaly inflow."
    },
    {
        "anchor": "Non-Abelian dual Meissner effect and confinement/deconfinement phase\n  transition in SU(3) Yang-Mills theory: The dual superconductivity is a promising mechanism for quark confinement. We\nproposed the non-Abelian dual superconductivity picture for SU(3) Yang-Mills\ntheory, and demonstrated the restricted field dominance (called conventionally\n\"Abelian\" dominance), and non-Abelian magnetic monopole dominance in the string\ntension. In the last conference, we have demonstrated by measuring the\nchromoelectric flux that the non-Abelian dual Meissner effect exists and\ndetermined that the dual superconductivity for SU(3) case is of type I, which\nis in sharp contrast to the SU(2) case: the border of type I and type II.\n  In this talk, we focus on the confinement/deconfinemen phase transition and\nthe non-Abelian dual superconductivity at finite temperature: We measure the\nchromoelectric flux between a pair of static quark and antiquark at finite\ntemperature, and investigate its relevance to the phase transition and the\nnon-Abelian dual Meissner effect.",
        "positive": "A strong-coupling analysis of two-dimensional O(N) sigma models with\n  $N\\geq 3$ on square, triangular and honeycomb lattices: Recently-generated long strong-coupling series for the two-point Green's\nfunctions of asymptotically free ${\\rm O}(N)$ lattice $\\sigma$ models are\nanalyzed, focusing on the evaluation of dimensionless renormalization-group\ninvariant ratios of physical quantities and applying resummation techniques to\nseries in the inverse temperature $\\beta$ and in the energy $E$. Square,\ntriangular, and honeycomb lattices are considered, as a test of universality\nand in order to estimate systematic errors. Large-$N$ solutions are carefully\nstudied in order to establish benchmarks for series coefficients and\nresummations. Scaling and universality are verified. All invariant ratios\nrelated to the large-distance properties of the two-point functions vary\nmonotonically with $N$, departing from their large-$N$ values only by a few per\nmille even down to $N=3$."
    },
    {
        "anchor": "Lattice QCD in Background Fields: Electromagnetic properties of hadrons can be computed by lattice simulations\nof QCD in background fields. We demonstrate new techniques for the\ninvestigation of charged hadron properties in electric fields. Our current\ncalculations employ large electric fields, motivating us to analyze chiral\ndynamics in strong QED backgrounds, and subsequently uncover surprising\nnon-perturbative effects present at finite volume.",
        "positive": "Solving the sign problem of two flavor scalar electrodynamics at finite\n  chemical potential: We explore two flavor scalar electrodynamics on the lattice, which has a\ncomplex phase problem at finite chemical potential. By rewriting the action in\nterms of dual variables this complex phase problem can be solved exactly. The\ndual variables are link- and plaquette occupation numbers, subject to local\nconstraints that have to be respected by the Monte Carlo algorithm. For the\nsimulation we use a local update as well as the newly developed \"surface worm\nalgorithm\", which is a generalization of the Prokof'ev Svistunov worm algorithm\nconcept for simulating the dual representation of abelian Gauge-Higgs models on\na lattice. We assess the performance of the two algorithms, present results for\nthe phase diagram and discuss condensation phenomena."
    },
    {
        "anchor": "Continuum Goldstone spectrum of two-color QCD at finite density with\n  staggered quarks: We carry out lattice simulations of two-color QCD and spectroscopy at finite\ndensity with two flavors of rooted-staggered quarks and a diquark source term.\nAs in a previous four-flavor study, for small values of the inverse gauge\ncoupling we observe a Goldstone spectrum which reflects the symmetry-breaking\npattern of a Gaussian symplectic chiral random-matrix ensemble (GSE) with Dyson\nindex $\\beta_D=4$, which corresponds to any-color QCD with adjoint quarks in\nthe continuum instead of QC$_2$D wih fundamental quarks. We show that this\nunphysical behavior occurs only inside of the bulk phase of $SU(2)$ gauge\ntheory, where the density of $Z_2$ monopoles is high. Using an improved gauge\naction and a somewhat larger inverse coupling to suppress these monopoles, we\ndemonstrate that the continuum Goldstone spectrum of two-color QCD,\ncorresponding to a Gaussian orthogonal ensemble (GOE) with Dyson index\n$\\beta_D=1$, is recovered also with rooted-staggered quarks once simulations\nare performed away from the bulk phase. We further demonstrate how this change\nof random-matrix ensemble is reflected in the distribution of eigenvalues of\nthe Dirac operator. By computing the unfolded level spacings inside and outside\nof the bulk phase, we demonstrate that, starting with the low-lying eigenmodes\nwhich determine the infrared physics, the distribution of eigenmodes\ncontinuously changes from the GSE to the GOE one as monopoles are suppressed.",
        "positive": "A comment on the index of the lattice Dirac operator and the\n  Ginsparg-Wilson relation: We pursue Ginsparg and Wilsons' block spin approach in the derivation of the\nGinsparg-Wilson relation and study the correspondence of the eigenmodes of the\nDirac operators in the continuum and lattice theories. After introducing a\nsuitable cut-off in the continuum theory, we identify unphysical modes of the\nlattice Dirac operator which do not correspond to any physical modes of the\nregulated continuum Dirac operator. We also consider zero modes in the\ncontinuum and lattice theories. Our studies give a physical interpretation of\nthe expression of the index defined on a lattice and a formal argument on the\nrelation of the indices between the continuum and lattice theories."
    },
    {
        "anchor": "Heavy-Light Mesons with Quenched Lattice NRQCD: Results on Decay\n  Constants: We present a quenched lattice calculation of heavy-light meson decay\nconstants, using non-relativistic (NRQCD) heavy quarks in the mass region of\nthe $b$ quark and heavier, and clover-improved light quarks. The NRQCD\nHamiltonian and the heavy-light current include the corrections at first order\nin the expansion in the inverse heavy quark mass. We study the dependence of\nthe decay constants on the heavy meson mass $M$, for light quarks with the tree\nlevel ($c_{SW}$ = 1), as well as the tadpole improved clover coefficient. We\ncompare decay constants from NRQCD with results from clover ($c_{SW}=1$) heavy\nquarks.\n  Having calculated the current renormalisation constant $Z_A$ in one-loop\nperturbation theory, we demonstrate how the heavy mass dependence of the\npseudoscalar decay constants changes after renormalisation. For the first time,\nwe quote a result for $f_B$ from NRQCD including the full one-loop matching\nfactors at $O(\\alpha/M)$.",
        "positive": "Baryons in the Gross-Neveu model in 1+1 dimensions at finite number of\n  flavors: In a recent work we studied the phase structure of the Gross-Neveu (GN) model\nin $1+1$ dimensions at finite number of fermion flavors $N_\\mathrm{f} = 2, 8,\n16$, finite temperature and finite chemical potential using lattice field\ntheory. Most importantly, we found an inhomogeneous phase at low temperature\nand large chemical potential, quite similar to the analytically solvable\n$N_\\mathrm{f} \\rightarrow \\infty$ limit. In the present work we continue our\nlattice field theory investigation of the finite-$N_\\mathrm{f}$ GN model by\nstudying the formation of baryons, their spatial distribution and their\nrelation to the chiral condensate. As a preparatory step we also discuss a\nlinear coupling of lattice fermions to the chemical potential."
    },
    {
        "anchor": "Parallel tempering and decorrelation of topological charge in full QCD: The improvement of simulations of QCD with dynamical Wilson fermions by\ncombining the Hybrid Monte Carlo algorithm with parallel tempering is studied\non $10^4$ and $12^4$ lattices. As an indicator for decorrelation the\ntopological charge is used.",
        "positive": "Scattering in a Euclidean formulation of relativistic quantum mechanics: A Euclidean formulation of relativistic quantum mechanics is discussed.\nRepresentations of the Hilbert space inner product and Poincar\\'e generators\nare all expressed in terms of Euclidean space-time variables. The formulation\ndoes not require analytic continuation and can be used to directly calculate\nscattering observables. A toy model is used to demonstrate the feasibility of\nperforming scattering calculations using the suggested computational methods."
    },
    {
        "anchor": "Finite volume effects in pion-kaon scattering and reconstruction of the\n  kappa(800) resonance: Simulating the kappa(800) on the lattice is a challenging task that starts to\nbecome feasible due to the rapid progress in recent-years lattice QCD\ncalculations. As the resonance is broad, special attention to finite-volume\neffects has to be paid, because no sharp resonance signal as from avoided level\ncrossing can be expected. In the present article, we investigate the finite\nvolume effects in the framework of unitarized chiral perturbation theory using\nnext-to-leading order terms. After a fit to meson-meson partial wave data,\nlattice levels for piK scattering are predicted. In addition, levels are shown\nfor the quantum numbers in which the sigma(600), f_0(980), a_0(980), phi(1020),\nK*(892), and rho(770) appear, as well as the repulsive channels. Methods to\nextract the kappa(800) signal from the lattice spectrum are presented. Using\npseudo-data, we estimate the precision that lattice data should have to allow\nfor a clear-cut extraction of this resonance. To put the results into context,\nin particular the required high precision on the lattice data, the sigma(600),\nthe P-wave resonances K*(892) and rho(770), and the repulsive piK, pipi phases\nare analyzed as well.",
        "positive": "Recent results of nucleon structure & matrix element calculations: A review of recent lattice calculations of nucleon structure and matrix\nelements of operators in nucleons is presented. It primarily covers\ndevelopments in the calculation of the matrix elements of the scalar, tensor,\npseudo-scalar, axial-vector and vector operators in the ground state of\nneutrons and protons in the isospin symmetric limit. Some preliminary\ncalculations of the electric dipole moment, the gravitational moments and\nstress-energy distribution, and the magnetic polarizability are briefly\ndescribed."
    },
    {
        "anchor": "Recent lattice results on finite temerature and density QCD, part II: We discuss recent progress in studies of QCD thermodynamics with almost\nphysical light quark masses and a physical value of the strange quark mass. We\nsummarize results on the transition temperature in QCD and analyze the relation\nbetween deconfinement and chiral symmetry restoration.",
        "positive": "Finite-size scaling around the critical point in the heavy quark region\n  of QCD: Finite-size scaling is investigated in detail around the critical point in\nthe heavy-quark region of nonzero temperature QCD. Numerical simulations are\nperformed with large spatial volumes up to the aspect ratio $N_s/N_t=12$ at a\nfixed lattice spacing with $N_t=4$. We show that the Binder cumulant and the\ndistribution function of the Polyakov loop follow the finite-size scaling in\nthe $Z(2)$ universality class for large spatial volumes with $N_s/N_t \\ge 9$,\nwhile, for $N_s/N_t \\le 8$, the Binder cumulant becomes inconsistent with the\n$Z(2)$ scaling. To realize the large-volume simulations in the heavy-quark\nregion, we adopt the hopping parameter expansion for the quark determinant: We\ngenerate gauge configurations using the leading order action including the\nPolyakov loop term for $N_t=4$, and incorporate the next-to-leading order\neffects in the measurements by the multipoint reweighting method. We find that\nthe use of the leading-order configurations is crucially effective in\nsuppressing the overlapping problem in the reweighting and thus reducing the\nstatistical errors."
    },
    {
        "anchor": "The torelon spectrum and the world-sheet axion: We present a major update on the spectrum of the closed flux-tube (torelon)\nin $D=3+1$ $SU(N)$ gauge theories. Namely, we calculate the excitation spectrum\nof a confining flux-tube which winds around a spatial torus as a function of\nits length $l$, for short as well as long tubes. We do so for $N=3,5,6$ and two\ndifferent values of the lattice spacing. Our states are characterised by the\nquantum numbers of spin $J$, transverse parity $P_{\\perp}$, longitudinal parity\n$P_{\\parallel}$ as well as by the longitudinal momentum $p_{\\parallel}$. Our\nextended basis of operators used in combination with the generalized eigenvalue\nmethod enables us to extract masses for all irreducible representations\ncharacterised by $\\{ |J|,P_{\\perp},P_{\\parallel} \\}$. We confirm that most of\nthe low-lying states are well described by the spectrum of the\nGoddard-Goldstone-Rebbi-Thorn string. In addition we provide strong evidence,\nthat in addition to string like states, massive modes exist on the world-sheet.\nMore precisely the ground state with quantum numbers ${|J|}^{P_{\\perp},\nP_{\\parallel}}=0^{--}$ exhibits a behaviour which is in agreement with the\ninterpretation of being an axion on the world-sheet of the flux-tube. This\nstate arises from a topological interaction term included in the effective\nworld-sheet action. In addition we observe that the second excited state with\n${|J|}^{P_{\\perp}, P_{\\parallel}}=0^{++}$ behaves as a massive mode with mass\ntwice that of the axion.",
        "positive": "Unquenched domain wall quarks with multi-bosons: The numerical simulation of domain wall quarks with the two-step multi-boson\n(TSMB) algorithm is considered. The inclusion of single quark flavours, as\nrequired for strange quarks, is discussed. The usage of computer memory can be\nkept relatively low, independently of the order of polynomial approximations.\nTests are performed with two flavours (N_f=2) of degenerate quarks near the\nN_t=4 thermodynamical cross over."
    },
    {
        "anchor": "2+1 Flavor Domain Wall Fermion QCD Lattices: Ensemble Production and\n  (some) Properties: The RBC and UKQCD Collaborations continue to produce 2+1 flavor domain wall\nfermion ensembles, currently focusing on an ensemble with a $96^3 \\times 192$\nvolume on SUMMIT at ORNL with $1/a \\approx 2.8$ GeV, and smaller ensembles at\nstronger couplings. The $1/a \\approx 2.8$ GeV ensemble uses the Exact One\nFlavor Algorithm for the strange quark, along with the Multisplitting\nPreconditioned Conjugate Gradient for solving the Dirac equation. We report on\nour progress and experience to date with the evolution of this ensemble.",
        "positive": "Modelling the quark propagator: The quark propagator is at the core of lattice hadron spectrum calculations\nas well as studies in other nonperturbative schemes. We investigate the quark\npropagator with an improved staggered action (Asqtad) and an improved gluon\naction, which provides good quality data down to small quark masses. This is\nused to construct ans\\\"{a}tze suitable for model hadron calculations as well as\nadding to our intuitive understanding of QCD."
    },
    {
        "anchor": "The Strong Coupling Constant from the Lattice 3-Gluon Vertex: We compute the QCD running coupling on the lattice as defined from the\n3-gluon vertex. We present the results of an exploratory study at $\\beta=6.0$\non a $16^4$ lattice, which show that for momenta larger than 2 \\Gev, the\ncoupling runs according to the 2-loop asymptotic formula, allowing a precise\ndetermination of the $\\Lambda$ parameter. Our renormalization procedure\ncorresponds to a momentum subtraction scheme in the continuum and, most\nremarkably, one does not need lattice perturbation theory to match the results\nto MSbar scheme. We obtain $\\alpha^{\\MSB}(M_Z) = 0.115 \\pm 0.003 \\pm 0.008$.",
        "positive": "How to Count Kinks: From the Continuum to the Lattice and Back: We investigate the matching between (1+1)-dimensional nonlinear field\ntheories coupled to an external stochastic environment and their lattice\nsimulations. In particular, we focus on how to obtain numerical results which\nare lattice-spacing independent, and on how to extract the correct effective\npotential which emerges from the simulations. As an application, we study the\nthermal production of kink-antikink pairs, obtaining a number density of pairs\nwhich is lattice-spacing independent and the effective barrier for pair\nproduction, i.e., the effective kink mass."
    },
    {
        "anchor": "Finite-volume effects in the hadronic vacuum polarization: We investigate finite-volume effects in the hadronic vacuum polarization,\nwith an eye toward the corresponding systematic error in the muon anomalous\nmagnetic moment. While it is well known that leading-order chiral perturbation\ntheory does not provide a good description of the hadronic vacuum polarization,\nit turns out that it gives a much better representation of finite-volume\neffects. Indications are that finite-volume effects cannot be ignored when the\naim is a few percent level accuracy for the hadronic contribution to the muon\nanomalous magnetic moment, even when $m_\\pi L \\sim 4$ and $m_\\pi \\sim 200$ MeV.",
        "positive": "How to Put a Heavier Higgs on the Lattice: Lattice work, exploring the Higgs mass triviality bound, seems to indicate\nthat a strongly interacting scalar sector in the minimal standard model cannot\nexist while low energy QCD phenomenology seems to indicate that it could. We\nattack this puzzle using the 1/N expansion and discover a simple criterion for\nselecting a lattice action that is more likely to produce a heavy Higgs\nparticle. Our large $N$ calculation suggests that the Higgs mass bound might be\naround $850 GeV$, which is about 30% higher than previously obtained."
    },
    {
        "anchor": "Better than $1/Mflops sustained: a scalable PC-based parallel computer\n  for lattice QCD: We study the feasibility of a PC-based parallel computer for medium to large\nscale lattice QCD simulations. The E\\\"otv\\\"os Univ., Inst. Theor. Phys. cluster\nconsists of 137 Intel P4-1.7GHz nodes with 512 MB RDRAM. The 32-bit, single\nprecision sustained performance for dynamical QCD without communication is 1510\nMflops/node with Wilson and 970 Mflops/node with staggered fermions. This gives\na total performance of 208 Gflops for Wilson and 133 Gflops for staggered QCD,\nrespectively (for 64-bit applications the performance is approximately halved).\nThe novel feature of our system is its communication architecture. In order to\nhave a scalable, cost-effective machine we use Gigabit Ethernet cards for\nnearest-neighbor communications in a two-dimensional mesh. This type of\ncommunication is cost effective (only 30% of the hardware costs is spent on the\ncommunication). According to our benchmark measurements this type of\ncommunication results in around 40% communication time fraction for lattices\nupto 48^3\\cdot96 in full QCD simulations. The price/sustained-performance ratio\nfor full QCD is better than $1/Mflops for Wilson (and around $1.5/Mflops for\nstaggered) quarks for practically any lattice size, which can fit in our\nparallel computer. The communication software is freely available upon request\nfor non-profit organizations.",
        "positive": "Dynamical overlap fermions, results with hybrid Monte-Carlo algorithm: We present first, exploratory results of a hybrid Monte-Carlo algorithm for\ndynamical, n_f=2, four-dimensional QCD with overlap fermions. As expected, the\ncomputational requirements are typically two orders of magnitude larger for the\ndynamical overlap formalism than for the more conventional (Wilson or\nstaggered) formulations."
    },
    {
        "anchor": "Three-pion effects in $K^0-\\bar{K}^0$ mixing: The rate of mixing between a neutral kaon and an anti-kaon ($K^0-\\bar{K}^0$)\nis given, in part, by a long-range matrix element, defined with two insertions\nof the weak Hamiltonian separated by physical, Minkowski time evolution. For\nphysical quark masses, the kaon mass lies above the two- and three-pion\nthresholds and, as a result, this long-range matrix element receives\ncontributions from intermediate on-shell $2\\pi$ and $3\\pi$ states. These\ncontributions cannot easily be captured in a finite Euclidean spacetime,\nmeaning that such matrix elements are not directly accessible via lattice QCD.\nIn this talk, we present a strategy for combining quantities that can be\nextracted in numerical lattice QCD calculations in order to reproduce the\nphysical, infinite-volume long-range amplitude for $K^0-\\bar{K}^0$. The key\nnovelty relative to published work is that we fully include the effects of\nthree-particle states that were previously neglected. The strategy is built on\nexisting formalism for long-range matrix elements with two-particle\nintermediate states, together with the relativistic-field-theory finite-volume\nformalism for extracting three-hadron weak decays.",
        "positive": "A review on Glueball hunting: One of the most direct predictions of QCD is the existence of color-singlet\nstates called Glueballs, which emerge as a consequence of the gluon field\nself-interactions. Despite the outstanding success of QCD as a theory of the\nstrong interaction and decades of experimental and theoretical efforts, all but\nthe most basic properties of Glueballs are still being debated. In this talk, I\nwill review efforts aimed to understanding Glueballs and the current status of\nGlueball searches, including recent experimental results and lattice\ncalculations."
    },
    {
        "anchor": "Dual simulation of a Polyakov loop model at finite baryon density:\n  correlations and screening masses: Computations of screening masses in finite-temperature QCD at finite density\nare plagued by the sign problem and have been performed so far with an\nimaginary chemical potential. Here, we use a dual formulation of a\nPolyakov-loop model which allows the determination of screening masses at real\nbaryon chemical potential. This is a second paper in a series devoted to a\ndetailed study of dual Polyakov-loop models at finite density. While the first\npaper was mainly devoted to establishing the phase diagram of the model, here\nwe compute correlation functions of the Polyakov loops and the second-moment\ncorrelation length at non-zero chemical potential. This enables us to evaluate\nnumerically the screening masses from correlations of the real and imaginary\nparts of the Polyakov loops. We also compute these masses in the mean-field\napproximation and compare with numerical results. In addition, we provide a\nquantitative improvement of the general phase diagram presented in the first\npaper.",
        "positive": "Calculation of the pion electromagnetic form factor from lattice QCD: We present a lattice calculation of the vector form factor of the pion for\ntwo flavours of non-perturbatively O(a) improved Wilson fermions. For the\nmeasurements we utilise the CLS ensembles which include various lattice\nspacings and pion masses down to about 250 MeV. To obtain a fine momentum\nresolution near zero momentum transfer (q^2) partially twisted boundary\nconditions are employed using several twist angles. Due to the fine resolution\naround q^2=0 we are able to determine the slope of the form factor and, in\nturn, extract the charge radius of the pion without any model dependence. The\nresults for the form factor and the charge radius are then compared to chiral\nperturbation theory and phenomenological models which are used to extrapolate\nthe results to the physical point."
    },
    {
        "anchor": "One-Flavour Hybrid Monte Carlo with Wilson Fermions: The Wilson fermion determinant can be written as product of the determinants\nof two hermitian positive definite matrices. This formulation allows to\nsimulate non-degenerate quark flavors by means of the hybrid Monte Carlo\nalgorithm. A major numerical difficulty is the occurrence of nested inversions.\nWe construct a Uzawa iteration scheme which treats the nested system within one\niterative process.",
        "positive": "Hadronic structure from the lattice: In recent years the investigation of hadron structure using lattice\ntechniques has attracted growing attention. In this talk we give an overview on\nrecent work with a focus on results for nucleon spectrum and structure from the\nQCDSF collaboration."
    },
    {
        "anchor": "Deep Learning Beyond Lefschetz Thimbles: The generalized thimble method to treat field theories with sign problems\nrequires repeatedly solving the computationally-expensive holomorphic flow\nequations. We present a machine learning technique to bypass this problem. The\ncentral idea is to obtain a few field configurations via the flow equations to\ntrain a feed-forward neural network. The trained network defines a new manifold\nof integration which reduces the sign problem and can be rapidly sampled. We\npresent results for the $1+1$ dimensional Thirring model with Wilson fermions\non sizable lattices. In addition to the gain in speed, the parameterization of\nthe integration manifold we use avoids the \"trapping\" of Monte Carlo chains\nwhich plagues large-flow calculations, a considerable shortcoming of the\nprevious attempts.",
        "positive": "New developments in multi-meson systems: New developments in the study of multi-meson systems are reviewed. We\nhighlight a new recursive algorithm for generating the requisite contractions\nneeded for studying complex systems of mesons involving large numbers of\nparticles or multiple species of particles. First results on mixed species\nsystems involving pions and kaons are also presented."
    },
    {
        "anchor": "(1+1)-dimensional Baryons from the SU(N) Color-Flavor Transformation: The color-flavor transformation, an identity that connects two integrals,\neach of which is over one of a dual pair of Lie groups acting in the fermionic\nFock space, is extended to the case of the special unitary group. Using this\nextension, a toy model of lattice QCD is studied: N_f species of spinless\nfermions interacting with strongly coupled SU(N_c) lattice gauge fields in 1+1\ndimensions. The color-flavor transformed theory is expressed in terms of gauge\nsinglets, the meson fields, organized into sectors distinguished by the\ndistribution of baryonic flux. A comprehensive analytical and numerical search\nis made for saddle-point configurations of the meson fields, with various\ntopological charges, in the vacuum and single-baryon sectors. Two definitions\nof the static baryon on the square lattice, straight and zigzag, are\ninvestigated. The masses of the baryonic states are estimated using the\nsaddle-point approximation for large N_c.",
        "positive": "Anderson localization through Polyakov loops: lattice evidence and\n  Random matrix model: We investigate low-lying fermion modes in SU(2) gauge theory at temperatures\nabove the phase transition. Both staggered and overlap spectra reveal\ntransitions from chaotic (random matrix) to integrable (Poissonian) behavior\naccompanied by an increasing localization of the eigenmodes. We show that the\nlatter are trapped by local Polyakov loop fluctuations. Islands of such \"wrong\"\nPolyakov loops can therefore be viewed as defects leading to Anderson\nlocalization in gauge theories. We find strong similarities in the spatial\nprofile of these localized staggered and overlap eigenmodes. We discuss\npossible interpretations of this finding and present a sparse random matrix\nmodel that reproduces these features."
    },
    {
        "anchor": "Index of a family of lattice Dirac operators and its relation to the\n  non-abelian anomaly on the lattice: In the continuum, a topological obstruction to the vanishing of the\nnon-abelian anomaly in 2n dimensions is given by the index of a certain Dirac\noperator in 2n+2 dimensions, or equivalently, the index of a 2-parameter family\nof Dirac operators in 2n dimensions. In this paper an analogous result is\nderived for chiral fermions on the lattice in the Overlap formulation. This\ninvolves deriving an Index Theorem for a family of lattice Dirac operators\nsatisfying the Ginsparg--Wilson relation. The index density is proportional to\nLuescher's topological field in 2n+2 dimensions.",
        "positive": "One-loop matching of lattice and continuum heavy-light axial vector\n  currents using NRQCD: The temporal component of the heavy-light axial vector current is constructed\nto one-loop order in perturbation theory and to order 1/M, where M is the heavy\nquark mass, in terms of operators suitable for use in lattice simulations of B\nand D mesons. The O(a)-improved clover action is used for the massless light\nquark, where a is the lattice spacing, and propagation of the heavy quark is\ndescribed by a nonrelativistic lattice action."
    },
    {
        "anchor": "Spectrum of SU(2) SUSY Yang-Mills Theory with a light gluino: We report on new results for the low lying spectrum of N=1 SUSY Yang-Mills\nTheory with SU(2) as the gauge group. Simulating on larger lattices at \\kappa =\n0.194 and \\beta = 2.3, we slowly approach the supersymmetric limit at\nm_{gluino} = 0.",
        "positive": "Topological susceptibility of $2d~\\mathrm{CP}^1$ or $\\mathrm{O}(3)$\n  non-linear $\u03c3$-model: is it divergent or not?: The topological susceptibility of $2d$ $\\mathrm{CP}^{N-1}$ models is\nexpected, based on perturbative computations, to develop a divergence in the\nlimit $N \\to 2$, where these models reduce to the well-known non-linear\n$\\mathrm{O}(3)$ $\\sigma$-model. The divergence is due to the dominance of\ninstantons of arbitrarily small size and its detection by numerical lattice\nsimulations is notoriously difficult, because it is logarithmic in the lattice\nspacing. We approach the problem from a different perspective, studying the\nbehavior of the model when the volume is fixed in dimensionless lattice units,\nwhere perturbative predictions are turned into more easily checkable behaviors.\nAfter testing this strategy for $N = 3$ and $4$, we apply it to $N = 2$,\nadopting at the same time a multicanonic algorithm to overcome the problem of\nrare topological fluctuations on asymptotically small lattices. Our final\nresults fully confirm, by means of purely non-perturbative methods, the\ndivergence of the topological susceptibility of the $2d$ $\\mathrm{CP}^1$ model."
    },
    {
        "anchor": "\u03b7 and \u03b7' mixing from Lattice QCD: We present a lattice QCD computation of $\\eta$ and $\\eta^\\prime$ masses and\nmixing angles, for the first time controlling continuum and quark mass\nextrapolations. The results for the eta mass 551(8)(6) MeV (first error\nstatistical, second systematic) and the eta' mass 1006(54)(38)(+61) MeV (third\nerror from our method) are in excellent agreement with experiment. Our data\nshow that the mixing in the quark flavour basis can be described by a single\nmixing angle of 46(1)(3) degree indicating that the eta' is mainly a flavour\nsinglet state.",
        "positive": "One-loop lattice artifacts of a dynamical charm quark: For a few observables in O(a) improved lattice QCD, we compute discretization\neffects arising from the vacuum polarization of a heavy quark at one-loop\norder. In particular, the force between static quarks, the running coupling in\nthe Schrodinger functional and a related quantity, {\\bar \\upsilon}, are\nconsidered. Results show that the cutoff effects of a dynamical charm quark are\ntypically smaller than those present in the pure gauge theory. This\nperturbative result is a good indication that dynamical charm quarks are\nfeasible already now."
    },
    {
        "anchor": "Machine learning Hadron Spectral Functions in Lattice QCD: Hadron spectral functions carry all the information of hadrons and are\nencoded in the Euclidean two-point correlation functions. The extraction of\nhadron spectral functions from the correlator is a typical ill-posed inverse\nproblem and infinite number of solutions to this problem exists. We propose a\nnovel neural network (sVAE) based on the Variation Auto-Encoder (VAE) and\nBayesian theorem. Inspired by the maximum entropy method (MEM) we construct the\nloss function of the neural work such that it includes a Shannon-Jaynes entropy\nterm and a likelihood term. The sVAE is then trained to provide the most\nprobable spectral functions. For the training samples of spectral function we\nused general spectral functions produced from the Gaussian Mixture Model. After\nthe training is done we performed the mock data tests with input spectral\nfunctions consisting 1) only a free continuum, 2) only a resonance peak, 3) a\nresonance peak plus a free continuum and 4) a NRQCD motivated spectral\nfunction. From the mock data test we find that the sVAE in most cases is\ncomparable to the maximum entropy method in the quality of reconstructing\nspectral functions and even outperforms the MEM in the case where the spectral\nfunction has sharp peaks with insufficient number of data points in the\ncorrelator. By applying to temporal correlation functions of charmonium in the\npseudoscalar channel obtained in the quenched lattice QCD at 0.75 $T_c$ on\n$128^3\\times96$ lattices and $1.5$ $T_c$ on $128^3\\times48$ lattices, we find\nthat the resonance peak of $\\eta_c$ extracted from both the sVAE and MEM has a\nsubstantial dependence on the number of points in the temporal direction\n($N_\\tau$) adopted in the lattice simulation and $N_\\tau$ larger than 48 is\nneeded to resolve the fate of $\\eta_c$ at 1.5 $T_c$.",
        "positive": "Large volumes and spectroscopy of walking theories: A detailed investigation of finite size effects is performed for SU(2) gauge\ntheory with two fermions in the adjoint representation, which previous lattice\nstudies have shown to be inside the conformal window. The system is\ninvestigated with different spatial and temporal boundary conditions on\nlattices of various spatial and temporal extensions, for two values of the bare\nfermion mass representing a {\\em heavy} and {\\em light} fermion regime. Our\nstudy shows that the infinite volume limit of masses and decay constants in the\nmesonic sector is reached only when the mass of the pseudoscalar particle\n$M_\\mathrm{PS}$ and the spatial lattice size $L$ satisfy the relation $L\nM_\\mathrm{PS} \\ge 15$. This bound, which is at least a factor of three higher\nthan what observed in QCD, is a likely consequence of the different spectral\nsignatures of the two theories, with the scalar isosinglet ($0^{++}$ glueball)\nbeing the lightest particle in our model. In addition to stressing the\nimportance of simulating large lattice sizes, our analysis emphasises the need\nto understand quantitatively the {\\em full} spectrum of the theory rather than\njust the spectrum in the mesonic isotriplet sector. While for the lightest\nfermion measuring masses from gluonic operators proves to be still challenging,\nreliable results for glueball states are obtained at the largest fermion mass\nand, in the mesonic sector, for both fermion masses. As a byproduct of our\ninvestigation, we perform a finite size scaling of the pseudoscalar mass and\ndecay constant. The data presented in this work support the conformal behaviour\nof this theory with an anomalous dimension $\\gamma_* \\simeq 0.37$."
    },
    {
        "anchor": "Scalar mesons and tetraquarks from twisted mass lattice QCD: We study light scalar mesons with particular focus on the a_0(980) using\nlattice QCD with 2+1+1 dynamical quark flavors. To investigate the structure of\nthese scalar mesons and to identify, whether a sizeable tetraquark component is\npresent, we use a large set of operators, including diquark-antidiquark,\nmesonic molecule and two-meson operators. We find that the low-lying states\noverlap essentially exclusively with two-meson states. This indicates that in\nthe channels investigated no tightly bound four-quark states of either\nmolecular or diquark-antidiquark type exist.",
        "positive": "Thermodynamics for SU(2) pure gauge theory using gradient flow: We present the scale-setting function and the equation of state of the pure\nSU(2) gauge theory using the gradient flow method. We propose a reference scale\nt0 for the SU(2) gauge theory satisfying $t^2\\langle E \\rangle|_{t=t_0} = 0.1$.\nThis reference value is fixed by a natural scaling-down of the standard\nt0-scale for the SU(3) gauge theory based on the perturbative analyses. We also\nshow the thermodynamic quantities as a function of $T/T_c$, which are derived\nby the energy-momentum tensor using the small flow time expansion of the\ngradient flow."
    },
    {
        "anchor": "Strong Coupling Expansion for Scattering Phases in Hamiltonian Lattice\n  Field Theories - I. the $(d+1)$-dimensional Ising model: A systematic method to obtain strong coupling expansions for scattering\nquantities in Hamiltonian lattice field theories is presented. I develop the\nconceptual ideas by means of the Hamiltonian field theory analogue of the Ising\nmodel, in $d$ space and one time dimension. The main result is a convergent\nseries representation for the sacttering states and the transition matrix. To\nbe explicit the special cases of $d=1$ and $d=3$ spatial dimensions are\ndiscussed in detail. I compute the next-to-leading order approximation for the\nphase shifts. The application of the method to investigate low-energy\nscattering phenomena in lattice gauge theory and QCD is proposed.",
        "positive": "Excited nucleon spectrum with two flavors of dynamical fermions: We compute the spectrum of excited nucleons using the anisotropic Wilson\nlattice with two flavors of dynamical fermions. Using optimized sets of\noperators which transform irreducibly under the octahedral group, matrices of\ncorrelation functions are computed. We apply the variational method to these\nmatrices to extract excited energy eigenstates. We obtain several states for\neach irrep and identify the continuum spin for the lowest-lying states,\nincluding a $J^P={5/2}^-$ state."
    },
    {
        "anchor": "Gauge-variant propagators and the running coupling from lattice QCD: On the occasion of the 70th birthday of Prof. Adriano Di Giacomo we report on\nrecent numerical computations of the Landau gauge gluon and ghost propagators\nas well as of a non-symmetric MOM-scheme ghost-gluon vertex in quenched and\nfull lattice QCD. Special emphasis is paid to the Gribov copy problem and to\nthe unquenching effect. The corresponding running coupling \\alpha_s(q^2) is\nfound and shown to decrease for q^2 \\le 0.3 GeV^2 in the infrared limit. No\nindication for a non-trivial infrared fixed point is seen in agreement with\nfindings from truncated systems of Dyson-Schwinger equations treated on a\nfour-dimensional torus.",
        "positive": "Numerical simulations with two flavours of twisted-mass Wilson quarks\n  and DBW2 gauge action: Discretisation errors in two-flavour lattice QCD with Wilson-quarks and DBW2\ngauge action are investigated by comparing numerical simulation data at two\nvalues of the bare gauge coupling. Both non-zero and zero twisted mass values\nare considered. The results, including also data from simulations using the\nWilson plaquette gauge action, are compared to next-to-leading order chiral\nperturbation theory formulas."
    },
    {
        "anchor": "Spontaneous supersymmetry breaking in the two-dimensional N=1\n  Wess-Zumino model: We study the phase diagram of the two-dimensional N=1 Wess-Zumino model on\nthe lattice using Wilson fermions and the fermion loop formulation. We give a\ncomplete nonperturbative determination of the ground state structure in the\ncontinuum and infinite volume limit. We also present a determination of the\nparticle spectrum in the supersymmetric phase, in the supersymmetry broken\nphase and across the supersymmetry breaking phase transition. In the\nsupersymmetry broken phase we observe the emergence of the Goldstino particle.",
        "positive": "Calculating the I=2 Pion Scattering Length Using Tadpole Improved Clover\n  Wilson Action on Coarse Anisotropic Lattices: In an exploratory study, using the tadpole improved clover Wilson quark\naction on small, coarse and anisotropic lattices, the $\\pi\\pi$ scattering\nlength in the I=2 channel is calculated within quenched approximation. A new\nmethod is proposed which enables us to make chiral extrapolation of our lattice\nresults without calculating the decay constant on the lattice. Finite volume\nand finite lattice spacing errors are analyzed and the results are extrapolated\ntowards the infinite volume and continuum limit. Comparisons of our lattice\nresults with the new experiment and the results from Chiral Perturbation Theory\nare made. Good agreements are found."
    },
    {
        "anchor": "Bottomonia correlators and spectral functions at zero and finite\n  temperature: We present preliminary studies of bottomonia spectral functions at zero and\nfinite temperature using quenched anisotropic lattices. The heavy quark is\ntreated within Fermilab approach. We find no modification of the $\\eta_b$ and\n$\\Upsilon$ states up to temperatures $2.3T_c$ while our study suggest\ndissolution of $\\chi_b$ state at $1.15T_c$.",
        "positive": "Heavy quark momentum diffusion coefficient from the lattice: We report progress towards computing the heavy quark momentum diffusion\ncoefficient from the lattice correlator of two chromoelectric fields attached\nto a Polyakov loop in pure SU(3) gauge theory. Using a multilevel algorithm and\ntree-level improvement, we study the behavior of the diffusion coefficient as a\nfunction of temperature in the wide range $1.1 < T/Tc < 10^4$."
    },
    {
        "anchor": "Planar Thirring Model in the U(2$N$)-symmetric limit: I review the Thirring model in 2+1$d$ dimensions, focussing in particular on\npossible strongly-interacting UV-stable fixed points of the renormalisation\ngroup, corresponding to a continuous phase transition where a U($2N$) global\nsymmetry spontaneously breaks to U($N)\\otimes$U($N$). Since there is no small\nparameter in play, a systematic non-perturbative approach such as numerical\nsimulation of lattice field theory is mandated. I compare and contrast various\nformulations, paying particular attention to models formulated with either\nstaggered or domain wall lattice fermions. Domain wall fermions, which\nfaithfully capture U($2N$) symmetry in the limit of wall separation\n$L_s\\to\\infty$, predict a critical flavor number $1<N_c<2$.",
        "positive": "The study of the Three Nucleon Force in full QCD Lattice calculations: We study the three nucleon force in the triton channel using dynamical clover\nfermion lattice QCD. The Nambu-Bethe-Salpeter wave function is utilized to\nobtain the potentials among three nucleons. Since the straightforward\ncalculation is prohibitively expensive, two different frameworks are developed\nto meet the challenge. In the first method, we study the effective two nucleon\npotentials in the three nucleon system, where the differences between the\neffective two nucleon potentials and the genuine two nucleon potentials\ncorrespond to the three nucleon system effect, part of which is originated from\nthe three nucleon force. The calculation is performed using Nf=2 clover fermion\nat m(\\pi)= 1.13GeV generated by CP-PACS Collaboration, and Nf=2+1 clover\nfermion at m(\\pi)= 0.70, 0.57GeV generated by PACS-CS Collaboration. In the\nsecond method, we study the three nucleon system with 3D-configuration of\nnucleons fixed. This enables us to extract the three nucleon force directly, if\nboth of parity-even and parity-odd two nucleon potentials are provided. Since\nparity-odd two nucleon potentials are not available in lattice QCD at this\nmoment, we propose a new general procedure to identify the three nucleon force\nusing only parity-even two nucleon potentials. The calculation are performed\nwith Nf=2 clover fermion at m(\\pi)= 1.13GeV generated by CP-PACS Collaboration,\nemploying the linear setup for the 3D-configuration. Preliminary results for\nthe scalar/isoscalar three nucleon force are presented."
    },
    {
        "anchor": "Glueballs, strings and topology in SU(N) gauge theory: I show how one can use lattice methods to calculate various continuum\nproperties of SU(N) gauge theories; in part to explore old ideas that N=3 might\nbe close to N=infinity. I describe calculations of the low-lying `glueball'\nmass spectrum, of the string tensions of k-strings and of topological\nfluctuations for N=2,3,4,5. We find that mass ratios appear to show a rapid\napproach to the large-N limit, and, indeed, can be described all the way down\nto SU(2) using just a leading O(1/NxN) correction. We confirm that the smooth\nlarge-N limit we find is confining and is obtained by keeping a constant 't\nHooft coupling. We find that the ratio of the k=2 string tension to the k=1\nfundamental string tension is much less than the naive (unbound) value of 2 and\nis considerably greater than the naive bag model prediction; in fact we find\nthat it is consistent, within quite small errors, with either the\nM(-theory)QCD-inspired conjecture or with `Casimir scaling'. Finally I describe\ncalculations of the topological charge of the gauge fields. We observe that, as\nexpected, the density of small-size instantons vanishes rapidly as N increases,\nwhile the topological susceptibility appears to have a non-zero N=infinity\nlimit.",
        "positive": "B_s meson excited states from the lattice: This is a follow-up to our earlier work [Phys. Rev. D 65, 014512 (2002); Eur.\nPhys. J. C 28, 79 (2003); Phys. Rev. D 69, 094505 (2004)] for the energies and\nthe charge (vector) and matter (scalar) distributions for S-wave states in a\nheavy-light meson, where the heavy quark is static and the light quark has a\nmass about that of the strange quark. We study the radial distributions of\nhigher angular momentum states, namely P- and D-wave states. In nature the\nclosest equivalent of this heavy-light system is the B_s meson.\n  The calculation is carried out with dynamical fermions on a 16^3 times 32\nlattice with a lattice spacing of about 0.10 fm generated with the\nnon-perturbatively improved clover action. It is shown that several features of\nthe energies and radial distributions are in qualitative agreement with what\none expects from a simple one-body Dirac equation interpretation."
    },
    {
        "anchor": "Remarks on the pion-nucleon sigma-term: The pion-nucleon $\\sigma$-term can be stringently constrained by the\ncombination of analyticity, unitarity, and crossing symmetry with\nphenomenological information on the pion-nucleon scattering lengths. Recently,\nlattice calculations at the physical point have been reported that find lower\nvalues by about $3\\sigma$ with respect to the phenomenological determination.\nWe point out that a lattice measurement of the pion-nucleon scattering lengths\ncould help resolve the situation by testing the values extracted from\nspectroscopy measurements in pionic atoms.",
        "positive": "Improved performance of QCD code on ALiCE: We present results for the performance of QCD code on ALiCE, the Alpha-Linux\nCluster Engine at Wuppertal. We describe the techniques employed to optimise\nthe code, including the metaprogramming of assembler kernels, the effects of\ndata layout and an investigation into the overheads incurred by the\ncommunication."
    },
    {
        "anchor": "Highly anisotropic lattices for Yang-Mills theory: In this conference proceeding, we investigate the physical anisotropy in\nterms of the temporal and spatial lattice spacings in relation to the bare\nparameters of SU(2) pure gauge theory using Wilson gradient flow. Anisotropic\nlattices have a wide range of applications, from thermodynamic calculations in\nQCD to very recent real-time simulations using the complex Langevin method. We\nfind an almost linear relationship between the bare and renormalized\nanisotropy. Using a parametrization that includes nonlinear effects and was\nearlier proposed for SU(3) theory, we obtain a good description of the coupling\ndependence of the anisotropy with only two fitting parameters. Our observation\nof an approximately linear relationship and this parametrization should\nstrongly reduce the computational effort of anisotropic lattice calculations in\nthe future.",
        "positive": "Study of the Decoupling of Heavy Fermions in a Z_2 Scalar-Fermion Model: According to one-loop perturbation theory, fermions whose masses are totally\ngenerated from Yukawa couplings do not decouple in the heavy mass limit. We\ninvestigate this issue nonperturbatively in a 4-dimensional $Z_2$\nscalar-fermion model with staggered fermions. Our data at intermediate and\nstronger Yukawa couplings on $8^4$ and $12^4$ lattices suggest the\nnondecoupling of heavy fermions as predicted from one-loop calculation.\nHowever, at the strongest Yukawa coupling where a possible multi-critical point\nmay come into play, we cannot be conclusive."
    },
    {
        "anchor": "A non-perturbative calculation of the mass of the Bc: We present a calculation of the mass of the 1S0 pseudoscalar anti-b c (Bc)\nstate using a non-perturbative measurement from quenched lattice QCD. We find\nM_Bc = 6.386(9)(98)(15) GeV where the first error is statistical, the second\nsystematic due to the quark mass ambiguities and quenching and the third the\nsystematic error due to the estimation of mass of the eta_b.",
        "positive": "First results of baryon interactions from lattice QCD with physical\n  masses (1) -- General overview and two-nucleon forces --: We present the lattice QCD studies for baryon-baryon interactions for the\nfirst time with (almost) physical quark masses. $N_f = 2+1$ gauge\nconfigurations are generated with the Iwasaki gauge action and\nnonperturbatively $O(a)$-improved Wilson quark action with stout smearing on\nthe lattice of $(96 a)^4 \\simeq (8.2 {\\rm fm})^4$ with $a \\simeq 0.085$ fm,\nwhere $m_\\pi \\simeq 146$ MeV and $m_K \\simeq 525$ MeV. Baryon forces are\ncalculated from Nambu-Bethe-Salpeter (NBS) correlation functions using the\ntime-dependent HAL QCD method. In this report, we first give the general\noverview of the theoretical frameworks essential to the physical point\ncalculation of baryon forces. We then present the numerical results for the\ntwo-nucleon central and tensor forces in $^3S_1$-$^3D_1$ coupled channel and\nthe central force in $^1S_0$ channel. In particular, a clear signal is obtained\nfor the tensor force."
    },
    {
        "anchor": "The large-$N$ limit of the chiral condensate from twisted reduced models: We compute the large-$N$ limit of the QCD chiral condensate on the lattice\nusing twisted reduced models, and performing controlled continuum and chiral\nextrapolations. We perform two different calculations: one consists in\nextracting the chiral condensate from the quark mass dependence of the pion\nmass, and the other consists in extracting the chiral condensate from the\nbehaviour of the mode number of the Wilson-Dirac operator for small\neigenvalues. We find consistency between the results of the two methods, giving\na joint estimate of $\\lim_{N\\to\\infty}\\Sigma(N)/N=[184(13)$ MeV$]^3$\n($\\overline{\\mathrm{MS}}$, $\\mu=2$ GeV, taking the square root of the string\ntension $\\sqrt{\\sigma}=440$ MeV to set the scale), in remarkable agreement with\nthe $\\mathrm{SU}(3)$ 2-flavor FLAG result.",
        "positive": "Pion screening mass at finite chemical potential: We present a method to compute the responses of meson screening masses to the\nchemical potential by Taylor expanding the correlator using lattice QCD\nsimulation. We start by comparing the free theory lattice results with the\nanalytical expression. Then, using symmetry arguments, we obtain an expression\nfor the correlator in a series of the chemical potential at finite temperature.\nUsing this, we obtain the lowest order correction to the screening mass at a\nfinite chemical potential for temperatures around 2.5 GeV. Our lattice analysis\nis limited to isoscalar chemical potential for the pseudoscalar channel. The\ncalculations were performed using (2+1)-flavors of the Highly Improved\nStaggered Quark (HISQ/tree) action, with the ratio of the strange quark mass to\nthe light quark mass $m_s/m_\\ell=20$ corresponding to pion masses of 160 MeV."
    },
    {
        "anchor": "Non-perturbative improvement of the axial current in N_f=3 lattice QCD\n  with Wilson fermions and tree-level improved gauge action: The coefficient c_A required for O(a) improvement of the axial current in\nlattice QCD with N_f=3 flavors of Wilson fermions and the tree-level\nSymanzik-improved gauge action is determined non-perturbatively. The standard\nimprovement condition using Schroedinger functional boundary conditions is\nemployed at constant physics for a range of couplings relevant for simulations\nat lattice spacings of ~ 0.09 fm and below. We define the improvement condition\nprojected onto the zero topological charge sector of the theory, in order to\navoid the problem of possibly insufficient tunneling between topological\nsectors in our simulations at the smallest bare coupling. An interpolation\nformula for c_A(g_0^2) is provided together with our final results.",
        "positive": "Precision Lattice Computations in the Heavy Quark Sector: The phenomenology of the pseudo scalar mesons D_s and B_s and of the vector\nmesons D_s* and B_s* was investigated in simulations of quenched lattice QCD.\nThe work is particularly focused on the continuum limit and the minimisation of\nall systematic errors within the quenched approximation. The decay constants\nF_Ds and F_Ds* and the difference in the masses between the D_s and the D_s*\nwere determined from the direct computer simulation of lattice QCD in large\nphysical volume (L ~ 1.5 fm). As an aside, the renormalisation group invariant\ncharm quark mass M_c could be obtained from the simulation results. For the\nB_s- and the B_s*-meson, an interpolation in the meson mass to its physical\npoint was carried out for the decay constant and the mass splitting in the\ncontinuum limit. The functional form of the interpolation to the static limit\nwas guided by the prediction of the Heavy Quark Effective Theory (HQET). A set\nof conversion functions between HQET and QCD were derived and evaluated\nnumerically with input from perturbation theory."
    },
    {
        "anchor": "Phases of planar QCD on the torus: At infinite N, continuum Euclidean SU(N) gauge theory defined on a\nsymmetrical four torus has a rich phase structure with phases where the finite\nvolume system behaves as if it had infinite extent in some or all of the\ndirections. In addition, fermions are automatically quenched, so planar QCD\nshould be cheaper to solve numerically that full QCD. Large N is a relatively\nunexplored and worthwhile direction of research in lattice field theory.",
        "positive": "Nucleon electromagnetic form factors in two-flavour QCD: We present results for the nucleon electromagnetic form factors, including\nthe momentum transfer dependence and derived quantities (charge radii and\nmagnetic moment). The analysis is performed using O(a) improved Wilson fermions\nin Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a\nsystematic evaluation of the influence of excited states in three-point\ncorrelation functions, which lead to a biased evaluation, if not accounted for\ncorrectly. We argue that the use of summed operator insertions and fit\nans\\\"atze including excited states allow us to suppress and control this\neffect. We employ a novel method to perform joint chiral and continuum\nextrapolations, by fitting the form factors directly to the expressions of\ncovariant baryonic chiral effective field theory. The final results for the\ncharge radii and magnetic moment from our lattice calculations include, for the\nfirst time, a full error budget. We find that our estimates are compatible with\nexperimental results within their overall uncertainties."
    },
    {
        "anchor": "The quenched SU(2) fundamental scalar propagator in minimal Landau gauge: It is a long-standing question whether the confinement of matter fields in\nQCD has an imprint in the (gauge-dependent) correlation functions, especially\nthe propagators. As the analytic structure plays an important role in this\nquestion, high-precision data is necessary for lattice investigations. Also, it\nis interesting how this depends on the dimensionality of the theory. To make a\nstudy over a wide range of parameters possible this suggests to use scalar\nparticles. This is done here: The propagator of a fundamental scalar is studied\nin two, three, and four dimensions in quenched SU(2) Yang-Mills theory in\nminimal Landau gauge, both in momentum space and position space. Particular\nemphasis is put on the effects of renormalization. The results suggest a quite\nintricate volume dependence and the presence of an intrinsic mass scale, but no\nobvious connection to confinement.",
        "positive": "Lattice QCD and dense quark matter: This talk summarizes recent progress in lattice QCD for dense quark matter.\nThe emphasis is on the insights obtained from analytical results derived within\nchiral perturbation theory."
    },
    {
        "anchor": "Beyond the Standard Model with Precision Nucleon Matrix Elements on the\n  Lattice: Precision measurements of nucleons provide constraints on the Standard Model\nand can discern the signatures predicted for particles beyond the Standard\nModel (BSM). Knowing the Standard Model inputs to nucleon matrix elements will\nbe necessary to constrain the couplings of dark matter candidates such as the\nneutralino, to relate the neutron electric dipole moment to the CP-violating\ntheta parameter, or to search for new TeV-scale particles though non-$V-A$\ninteractions in neutron beta decay. However, these matrix elements derive from\nthe properties of quantum chromodynamics (QCD) at low energies, where\nperturbative treatments fail. Using lattice gauge theory, we can\nnonperturbatively calculate the QCD path integral on a supercomputer. In this\nproceeding, I will discuss a few representative areas in which lattice QCD\n(LQCD) can contribute to the search for BSM physics, emphasizing suppressed\noperators in neutron decay, and outline prospects for future development.",
        "positive": "Fast vectorized algorithm for the Monte Carlo Simulation of the Random\n  Field Ising Model: An algoritm for the simulation of the 3--dimensional random field Ising model\nwith a binary distribution of the random fields is presented. It uses\nmulti-spin coding and simulates 64 physically different systems simultaneously.\nOn one processor of a Cray YMP it reaches a speed of 184 Million spin updates\nper second. For smaller field strength we present a version of the algorithm\nthat can perform 242 Million spin updates per second on the same machine."
    },
    {
        "anchor": "Lattice baryon spectroscopy with multi-particle interpolators: In 2 + 1 flavour lattice QCD the spectrum of the nucleon is presented for\nboth parities using local meson-baryon type interpolating fields in addition to\nthe standard three-quark nucleon interpolators. The role of local five-quark\noperators in extracting the nucleon excited state spectrum via correlation\nmatrix techniques is explored on dynamical gauge fields with $m_\\pi$ = 293 MeV,\nleading to the observation of a state consistent with the S-wave $N\\pi$\nscattering threshold in the negative-parity sector. Furthermore, the robustness\nof the variational technique is examined by studying the spectrum on a variety\nof operator bases. Fitting a single-state ansatz to the eigenstate-projected\ncorrelators provides robust energies for the low-lying spectrum that are\nessentially invariant despite being extracted from qualitatively different\nbases.",
        "positive": "The pion quasiparticle in the low-temperature phase of QCD: We investigate the properties of the pion quasiparticle in the\nlow-temperature phase of two-flavor QCD on the lattice with support from chiral\neffective theory. We find that the pion quasiparticle mass is significantly\nreduced compared to its value in the vacuum, by contrast with the static\nscreening mass, which increases with temperature. By a simple argument, near\nthe chiral limit the two masses are expected to determine the quasiparticle\ndispersion relation. Analyzing two-point functions of the axial charge density\nat non-vanishing spatial momentum, we find that the predicted dispersion\nrelation and the residue of the pion pole are simultaneously consistent with\nthe lattice data at low momentum. The test, based on fits to the correlation\nfunctions, is confirmed by a second analysis using the Backus-Gilbert method."
    },
    {
        "anchor": "The spectrum of screening masses near T_c: predictions from universality: We discuss the spectrum of screening masses in a pure gauge theory near the\ndeconfinement temperature from the point of view of the dimensionally reduced\nmodel describing the spontaneous breaking of the center symmetry. Universality\narguments can be used to predict the values of the mass ratios in the scaling\nregion of the deconfined phase when the transition is of second order. One such\nprediction is that the scalar sector of the screening spectrum in SU(2) pure\ngauge theory contains a bound state of the fundamental excitation,\ncorresponding through universality to the bound state found in the 3D Ising\nmodel and phi^4 theory in the broken symmetry phase. A Monte Carlo evaluation\nof the screening masses in the gauge theory confirms the validity of the\nprediction. We briefly discuss the possibility of using similar arguments for\nfirst order deconfinement transitions, and in particular for the physically\nrelevant case of SU(3).",
        "positive": "Electromagnetic effects on topological observables in QCD: In this proceedings article we present a selected set of our lattice results\nregarding the effect that background electromagnetic fields have on the\ntopology of QCD. In particular, we report on the lattice spacing-dependence of\nthe axion-photon coupling as well as on the response of the topological\nsusceptibility to strong magnetic fields at nonzero temperatures. We\ndemonstrate that the ratio of topological susceptibilities at finite to zero\nmagnetic field has a well behaved continuum limit at low temperatures using a\nreweighting technique. Moreover, we study the scaling of the axion-photon\ncoupling towards the continuum limit and show that it is less severely affected\nby discretisation effects."
    },
    {
        "anchor": "Lattice renormalization of the static quark derivative operator: We give the analytical expressions and numerical values of radiative\ncorrections to the covariant derivative operator on the static quark line, used\nfor the lattice calculation of the Isgur-Wise form factors $\\tau_{1/2}(1)$ and\n$\\tau_{3/2}(1)$. Those corrections induce an enhancement of renormalized\nquantities if an hypercubic blocking is applied to the Wilson line, whereas\nthere is a reduction without such a blocking.",
        "positive": "Statistical analysis method for the worldvolume hybrid Monte Carlo\n  algorithm: We discuss the statistical analysis method for the worldvolume hybrid Monte\nCarlo (WV-HMC) algorithm [arXiv:2012.08468], which was recently introduced to\nsubstantially reduce the computational cost of the tempered Lefschetz thimble\nmethod. In the WV-HMC algorithm, the configuration space is a continuous\naccumulation (worldvolume) of deformed integration surfaces, and sample\naverages are considered for various subregions in the worldvolume. We prove\nthat, if a sample in the worldvolume is generated as a Markov chain, then the\nsubsample in the subregion can also be regarded as a Markov chain. This ensures\nthe application of the standard statistical techniques to the WV-HMC algorithm.\nWe particularly investigate the autocorrelation times for the Markov chains in\nvarious subregions, and find that there is a linear relation between the\nprobability to be in a subregion and the autocorrelation time for the\ncorresponding subsample. We numerically confirm this scaling law for a chiral\nrandom matrix model."
    },
    {
        "anchor": "Charm as a domain wall fermion in quenched lattice QCD: We report a study describing the charm quark by a domain-wall fermion (DWF)\nin lattice quantum chromodynamics (QCD). Our study uses a quenched gauge\nensemble with the DBW2 rectangle-improved gauge action at a lattice cutoff of\n$a^{-1} \\sim 3$ GeV. We calculate masses of heavy-light (charmed) and\nheavy-heavy (charmonium) mesons with spin-parity $J^P = 0^\\mp$ and $1^\\mp$,\nleptonic decay constants of the charmed pseudoscalar mesons ($D$ and $D_s$),\nand the $D^0$-$\\bar{D^0}$ mixing parameter. The charm quark mass is found to be\n$m^{\\bar{\\rm MS}}_{c}(m_{c})=1.24(1)(18)$ GeV. The mass splittings in\ncharmed-meson parity partners $\\Delta_{q,J=0}$ and $\\Delta_{q, J=1}$ are\ndegenerate within statistical errors, in accord with experiment, and they\nsatisfy a relation $\\Delta_{q=ud, J} > \\Delta_{q=s, J}$, also consistent with\nexperiment. A C-odd axial vector charmonium state, $h_c), lies 22(11) MeV above\nthe $\\chi_{c1}$ meson, or $m_{h_{c}} = 3533(11)_{\\rm stat.}$ MeV using the\nexperimental $\\chi_{c1}) mass. However, in this regard, we emphasize\nsignificant discrepancies in the calculation of hyperfine splittings on the\nlattice. The leptonic decay constants of $D$ and $D_s$ mesons are found to be\n$f_D=232(7)_{\\rm stat.}(^{+6}_{-0})_{\\rm chiral}(11)_{\\rm syst.}$ MeV and\n$f_{D_s}/f_{D} = 1.05(2)_{\\rm stat.}(^{+0}_{-2})_{\\rm chiral}(2)_{\\rm syst.}$,\nwhere the first error is statistical, the second a systematic due to chiral\nextrapolation and the third error combination of other known systematics. The\n$D^0$-$\\bar{D^0}$ mixing bag parameter, which enters the $\\Delta C = 2$\ntransition amplitude, is found to be $B_D(2{GeV})=0.845(24)_{\\rm\nstat.}(^{+24}_{-6})_{\\rm chiral}(105)_{\\rm syst.}$.",
        "positive": "Infrared properties of a prototype model for beyond-Standard Model\n  physics: We construct a prototype BSM model based on the SU(3) color gauge group and a\ncombination of 4 light (massless) and 8 heavy flavors. In the infrared, the\nSU(4) flavor chiral symmetry is spontaneously broken, while in the ultraviolet\nthis model exhibits the properties of the $N_f=12$ conformal fixed point.\nRenormalization group considerations predict the spectrum of such a system to\nshow hyperscaling, i.e. dimensionless ratios of hadron masses or decay\nconstants are independent of the heavy mass. Hyperscaling is present for bound\nstates of light, heavy, or a combination of heavy and light flavors and leads\nto a strongly predictive model. Despite chiral symmetry breaking, this system\nfeatures a spectrum exhibiting a very non-QCD like behavior. Furthermore, the\ngauge coupling becomes an irrelevant parameter. We support these expectations\nby presenting numerical results based on four different values of the heavy\nquark mass $am_h$, up to six different values of the light quark mass\n$am_\\ell$, and include, for the first time, preliminary data at a second value\nof the gauge coupling $\\beta$. Our model can be embedded in scenarios\ndescribing the Higgs boson either as a pseudo Nambu-Goldstone boson or a\ndilaton-like particle."
    },
    {
        "anchor": "Introductory lectures on lattice QCD at nonzero baryon number: These lecture notes contain an elementary introduction to lattice QCD at\nnonzero chemical potential. Topics discussed include chemical potential in the\ncontinuum and on the lattice; the sign, overlap and Silver Blaze problems; the\nphase boundary at small chemical potential; imaginary chemical potential; and\ncomplex Langevin dynamics. An incomplete overview of other approaches is\npresented as well. These lectures are meant for postgraduate students and\npostdocs with an interest in extreme QCD. A basic knowledge of lattice QCD is\nassumed but not essential. Some exercises are included at the end.",
        "positive": "The colour adjoint static potential from Wilson loops with generator\n  insertions and its physical interpretation: We discuss the non-perturbative computation and interpretation of a colour\nadjoint static potential based on Wilson loops with generator insertions.\nNumerical lattice results for SU(2) gauge theory are presented and compared to\ncorresponding perturbative results."
    },
    {
        "anchor": "N_f=2+1 flavour equation of state: We conclude our investigation on the QCD equation of state (EoS) with 2+1\nstaggered flavors and one-link stout improvement. We extend our previous study\n[JHEP 0601:089 (2006)] by choosing even finer lattices. These new results [for\ndetails see arXiv:1007.2580] support our earlier findings. Lattices with\nN_t=6,8 and 10 are used, and the continuum limit is approached by checking the\nresults at N_t=12. A Symanzik improved gauge and a stout-link improved\nstaggered fermion action is taken; the light and strange quark masses are set\nto their physical values. Various observables are calculated in the temperature\n(T) interval of 100 to 1000~MeV. We compare our data to the equation of state\nobtained by the \"hotQCD\" collaboration.",
        "positive": "Matrix elements and baryon spectroscopy from unquenched lattice QCD with\n  improved staggered quarks: We look for the effect of open decay channels on the masses of baryons in\nunquenched lattice QCD. We apply variational smearing using fuzzed basis states\nto a staggered nucleon operator. The signal for the s_bar s current in the\nnucleon is studied. The lattice calculations are done using improved staggered\nfermions."
    },
    {
        "anchor": "Center Vortices and the Gribov Horizon: We show how the infinite color-Coulomb energy of color-charged states is\nrelated to enhanced density of near-zero modes of the Faddeev-Popov operator,\nand calculate this density numerically for both pure Yang-Mills and gauge-Higgs\nsystems at zero temperature, and for pure gauge theory in the deconfined phase.\nWe find that the enhancement of the eigenvalue density is tied to the presence\nof percolating center vortex configurations, and that this property disappears\nwhen center vortices are either removed from the lattice configurations, or\ncease to percolate. We further demonstrate that thin center vortices have a\nspecial geometrical status in gauge-field configuration space: Thin vortices\nare located at conical or wedge singularities on the Gribov horizon. We show\nthat the Gribov region is itself a convex manifold in lattice configuration\nspace. The Coulomb gauge condition also has a special status; it is shown to be\nan attractive fixed point of a more general gauge condition, interpolating\nbetween the Coulomb and Landau gauges.",
        "positive": "Chiral Symmetry Breaking from Center Vortices: We analyze the creation of near-zero modes from would-be zero modes of\nvarious topological charge contributions from classical center vortices in\nSU(2) lattice gauge theory. We show that colorful spherical vortex and\ninstanton configurations have very similar Dirac eigenmodes and also vortex\nintersections are able to give rise to a finite density of near-zero modes,\nleading to chiral symmetry breaking via the Banks-Casher formula. We discuss\nthe influence of the magnetic vortex fluxes on quarks and how center vortices\nmay break chiral symmetry."
    },
    {
        "anchor": "Effective SU(2) Polyakov Loop Theories with Heavy Quarks on the Lattice: We compare SU(2) Polyakov loop models with different effective actions with\ndata from full two-color QCD simulations around and above the critical\ntemperature. We then apply the effective theories at finite temperature and\ndensity to extract quantities like Polyakov loop correlators, effective\nPolyakov loop potentials and baryon density.",
        "positive": "QCD thermodynamics from lattice calculations with non-equilibrium\n  methods: The SU(3) equation of state: A precise lattice determination of the equation of state in SU(3) Yang-Mills\ntheory is carried out by means of a simulation algorithm, based on Jarzynski's\ntheorem, that allows one to compute physical quantities in thermodynamic\nequilibrium, by driving the field configurations of the system out of\nequilibrium. The physical results and the computational efficiency of the\nalgorithm are compared with other state-of-the-art lattice calculations, and\nthe extension to full QCD with dynamical fermions and to other observables is\ndiscussed."
    },
    {
        "anchor": "B and Bs semileptonic decay form factors with NRQCD/HISQ quarks: We discuss our ongoing effort to calculate form factors for several B and Bs\nsemileptonic decays. We have recently completed the first unquenched\ncalculation of the form factors for the rare decay B -> K ll. Extrapolated over\nthe full kinematic range of q^2 via model-independent z expansion, these form\nfactor results allow us to calculate several Standard Model observables. We\ncompare with experiment (Belle, BABAR, CDF, and LHCb) where possible and make\npredictions elsewhere. We discuss preliminary results for Bs -> K l nu which,\nwhen combined with anticipated experimental results, will provide an\nalternative exclusive determination of |Vub|. We are exploring the possibility\nof using ratios of form factors for this decay with those for the unphysical\ndecay Bs -> eta_s as a means of significantly reducing form factor errors. We\nare also studying B -> pi l nu, form factors for which are combined with\nexperiment in the standard exclusive determination of |Vub|. Our simulations\nuse NRQCD heavy and HISQ light valence quarks on the MILC 2+1 dynamical asqtad\nconfigurations.",
        "positive": "Unconstrained Variables and Equivalence Relations for Lattice Gauge\n  Theories: We write the partition function for a lattice gauge theory, with compact\ngauge group, exactly in terms of unconstrained variables and show that, in the\nmean field approximation, the dynamics of pure gauge theories, invariant under\ncompact, continuous,groups of rank 1 is the same for all. We explicitly obtain\nthe equivalence for the case of SU(2) and U(1) and show that it obtains, also,\nif we consider saddle point configurations that are not,necessarily, uniform,\nbut only proportional to the identity for both groups. This implies that the\nphase diagrams of the (an)isotropic SU(2) theory and the (an)isotropic U(1)\ntheory in any dimension are identical, within this approximation, up to a\nre-evaluation of the numerical values of the coupling constants at the\ntransitions. Only nonuniform field configurations, that, also, belong to higher\ndimensional representations for Yang--Mills fields, will be able to p robe the\ndifference between them. We also show under what conditions the global symmetry\nof an anisotropic term in the lattice action can be promoted to a gauge\nsymmetry of the theory on layers and point out how deconstruction and flux\ncompactification scenaria may thus be studied on the lattice."
    },
    {
        "anchor": "Charmonium spectrum from quenched QCD on anisotropic lattices: We present our final results of the charmonium spectrum in quenched QCD on\nanisotropic lattices. Simulations are made with the plaquette gauge action and\na tadpole improved clover quark action employing $\\xi = a_s/a_t = 3$. We\ncalculate the spectrum of S- and P-states and their excitation, and study the\nscaling behavior of mass splittings. Comparison is made with the experiment and\nprevious lattice results. The issue of hyperfine splitting for different\nchoices of the clover coefficients obtained by Klassen is discussed.",
        "positive": "Influence of topology on the scale setting: Recently a new method to set the scale in lattice gauge theories, based on\nthe gradient flow generated by the Wilson action, has been proposed, and the\nsystematic errors of the new scales t0 and w0 have been investigated by various\ngroups. The Wilson flow provides also an interesting alternative smoothing\nprocedure in particular useful for the measurement of the topological charge as\na pure gluonic observable. We show the viability of this method for N=1\nsupersymmetric Yang-Mills theory by analysing the configurations produced by\nthe DESY-Muenster collaboration. For increasing flow time the topological\ncharge quickly approaches near-integer values. The topological susceptibility\nhas been measured for different fermion masses and its value is observed to\napproach zero in the chiral limit. Finally, the relation between the scale\ndefined by the Wilson flow and the topological charge has been investigated,\ndemonstrating a correlation between these two quantities."
    },
    {
        "anchor": "First direct lattice-QCD calculation of the $x$-dependence of the pion\n  parton distribution function: We present the first direct lattice-QCD calculation of the Bjorken-$x$\ndependence of the valence quark distribution of the pion. Using large-momentum\neffective theory (LaMET), we calculate the boosted pion state with long Wilson\nlink operators. After implementing the one-loop matching and meson mass\ncorrections, our result at $m_\\pi \\approx 310$ MeV is in agreement with those\nextracted from experimental data as well as from Dyson-Schwinger equation in\nsmall $x$ region, but a sizeable discrepancy in the large $x$ region. This\ndiscrepancy provides a nice opportunity to systematically study and disentangle\nthe artifacts in the LaMET approach, which will eventually help to discern\nvarious existing analyses in the literature.",
        "positive": "Normalizing flows for the real-time sign problem: We discuss the application of normalizing flows to bosonic lattice field\ntheories with real-time sign problems. A normalizing flow, once it is found for\nsuch a lattice field theory, is guaranteed to solve its sign problem. We argue\nfor the existence of normalizing flows for bosonic lattice field theories in\nthe Schwinger-Keldish formalism in a few ways. We then discuss how this\nexistence is a specific feature of bosonic theories: such arguments break down\nfor fermionic systems, whether at finite density or in real-time."
    },
    {
        "anchor": "Testing the fixed-point QCD action and the construction of chiral\n  currents: We present the first set of quenched QCD measurements using the recently\nparametrized fixed-point Dirac operator D^FP. We also give a general and\npractical construction of covariant densities and conserved currents for chiral\nlattice actions. The measurements include (a) hadron spectroscopy, (b)\ncorrections of small chiral deviations, (c) the renormalized quark condensate\nfrom finite-size scaling and, independently, spectroscopy, (d) the topological\nsusceptibility, (e) small eigenvalue distributions and random matrix theory,\nand (f) local chirality of near-zero modes and instanton-dominance.",
        "positive": "CP invariance of chiral gauge theories and Majorana-Yukawa couplings on\n  the lattice: The construction of CP-invariant lattice chiral gauge theories and the\nconstruction of lattice Majorana fermions with chiral Yukawa couplings is\nsubject to topological obstructions. In the present work we suggest lattice\nextensions of charge and parity transformation for Weyl fermions. This enables\nus to construct lattice chiral gauge theories that are CP invariant. For the\nconstruction of Majorana-Yukawa couplings, we discuss two models with\nsymplectic Majorana fermions: a model with two symplectic doublets, and one\nwith an auxiliary doublet."
    },
    {
        "anchor": "Non-perturbative renormalization in coordinate space for $N_f=2$\n  maximally twisted mass fermions with tree-level Symanzik improved gauge\n  action: We present results of a lattice QCD application of a coordinate space\nrenormalization scheme for the extraction of renormalization constants for\nflavour non-singlet bilinear quark operators. The method consists in the\nanalysis of the small-distance behaviour of correlation functions in Euclidean\nspace and has several theoretical and practical advantages, in particular: it\nis gauge invariant, easy to implement and has relatively low computational\ncost. The values of renormalization constants in the X-space scheme can be\nconverted to the MSbar scheme via 4-loop continuum perturbative formulae. Our\nresults for $N_f=2$ maximally twisted mass fermions with tree-level Symanzik\nimproved gauge action are compared to the ones from the RI-MOM scheme and show\nfull agreement with this method.",
        "positive": "Correction to four-loop RG functions in the two-dimensional lattice O(n)\n  $\u03c3$-model: We report the result of our evaluation of the Feynman diagrams appearing in\nthe determination of the four-loop renormalization group functions in the\ntwo-dimensional lattice O($n$) $\\sigma$-model by Caracciolo and Pelissetto. In\nthe list of the integrals used for the determination of those functions, we\nfind that three entries were not correctly evaluated. We give the values for\nthem corrected by us including those for all other integrals which we computed\nwith higher precision. These results are then applied to revise the\ndetermination of the second analytic correction to correlation length $\\xi$ and\nspin susceptibility $\\chi$ by Caracciolo et al. as well as our determination of\nthe mass gap by means of a finite volume technique where we explicitly made use\nof the four-loop $\\beta$-function. In both cases we find sizeable changes in\npredictions. In the meantime there appeared a paper by Alles et al. where they\nrevised one finite integral in the list of our corrected integrals. After\nhaving taken the new revised value into consideration, we found that there are\nno noticeable changes in the perturbative predictions of the present paper\nincluding the final conclusions."
    },
    {
        "anchor": "Check of a new non-perturbative mechanism for elementary fermion mass\n  generation: We consider a field theoretical model where a SU(2) fermion doublet,\nsubjected to non-Abelian gauge interactions, is also coupled to a complex\nscalar field doublet via a Yukawa and an irrelevant Wilson-like term. Despite\nthe presence of these two chiral breaking operators in the Lagrangian, an exact\nsymmetry acting on fermions and scalars prevents perturbative mass corrections.\nIn the phase where fermions are massless (Wigner phase) the Yukawa coupling can\nbe tuned to a critical value at which chiral transformations acting on fermions\nonly become a symmetry of the theory (up to cutoff effects). In the\nNambu-Goldstone phase of the critical theory a fermion mass term of dynamical\norigin is expected to arise in the Ward identities of the purely fermionic\nchiral transformations. Such a non-perturbative mechanism of dynamical mass\ngeneration can provide a \"natural\" (\\`a la 't Hooft) alternative to the Higgs\nmechanism adopted in the Standard Model. Here we lay down the theoretical\nframework necessary to demonstrate the existence of this mechanism by means of\nlattice simulations.",
        "positive": "Dual simulation of a Polyakov loop model at finite baryon density: phase\n  diagram and local observables: Many Polyakov loop models can be written in a dual formulation which is free\nof sign problem even when a non-vanishing baryon chemical potential is\nintroduced in the action. Here, results of numerical simulations of a dual\nrepresentation of one such effective Polyakov loop model at finite baryon\ndensity are presented. We compute various local observables such as energy\ndensity, baryon density, quark condensate and describe in details the phase\ndiagram of the model. The regions of the first order phase transition and the\ncrossover, as well as the line of the second order phase transition, are\nestablished. We also compute several correlation functions of the Polyakov\nloops."
    },
    {
        "anchor": "The kaon mass in 2+1+1 flavor twisted mass Wilson ChPT: We construct the chiral low-energy effective theory for 2+1+1 flavor lattice\nQCD with twisted mass Wilson fermions. In contrast to existing results we\nassume a heavy charm quark mass such that the D mesons are too heavy to appear\nas degrees of freedom in the effective theory. As an application we compute the\nkaon mass to 1-loop order in the LCE regime. The result contains a chiral\nlogarithm involving the neutral pion mass which has no analogue in continuum\nChPT.",
        "positive": "Unitarity Bounds for Semileptonic Decays in Lattice QCD: In this work we discuss in detail the non-perturbative determination of the\nmomentum dependence of the form factors entering in semileptonic decays using\nunitarity and analyticity constraints. The method contains several new elements\nwith respect to previous proposals and allows to extract, using suitable\ntwo-point functions computed non-perturbatively, the form factors at low\nmomentum transfer $q^2$ from those computed explicitly on the lattice at large\n$q^2$, without any assumption about their $q^2$-dependence. The approach will\nbe very useful for exclusive semileptonic $B$-meson decays, where the direct\ncalculation of the form factors at low $q^2$ is particularly difficult due to\nlarge statistical fluctuations and discretisation effects. As a testing ground\nwe apply our approach to the semileptonic $D \\to K \\ell \\nu_\\ell$ decay, where\nwe can compare the results of the unitarity approach to the explicit direct\nlattice calculation of the form factors in the full $q^2$-range. We show that\nthe method is very effective and that it allows to compute the form factors\nwith rather good precision."
    },
    {
        "anchor": "Solving the sign problems of the massless lattice Schwinger model with a\n  dual formulation: We derive an exact representation of the massless Schwinger model on the\nlattice in terms of dual variables which are configurations of loops, dimers\nand plaquette occupation numbers. When expressed with the dual variables the\npartition sum has only real and positive terms also when a chemical potential\nor a topological term are added -- situations where the conventional\nrepresentation has a complex action problem. The dual representation allows for\nMonte Carlo simulations without restrictions on the values of the chemical\npotential or the vacuum angle.",
        "positive": "Aspects of topological actions on the lattice: We consider a lattice action which forbids large fields, and which remains\ninvariant under smooth deformations of the field. Such a \"topological\" action\ndepends on one parameter, the field cutoff, but does not have a classical\ncontinuum limit as this cutoff approaches zero. We study the properties of such\nan action in 4d compact U(1) lattice gauge theory, and compare them with those\nof the Wilson action. In both cases, we find a weakly first-order transition\nseparating a confining phase where monopoles condense, and a Coulomb phase\nwhere monopoles are exponentially suppressed. We also find a different,\ncritical value of the field cutoff where monopoles completely disappear.\nFinally, we show that a topological action simplifies the measurement of the\nfree energy."
    },
    {
        "anchor": "Reconstruction of smeared spectral function from Euclidean correlation\n  functions: We propose a method to reconstruct smeared spectral functions from two-point\ncorrelation functions measured on the Euclidean lattice. Arbitrary smearing\nfunction can be considered as far as it is smooth enough to allow an\napproximation using Chebyshev polynomials. We test the method with numerical\nlattice data of Charmonium correlators. The method provides a framework to\ncompare lattice calculation with experimental data including excited state\ncontributions without assuming quark-hadron duality.",
        "positive": "Heavy-light mesons with staggered light quarks: We demonstrate the viability of improved staggered light quarks in studies of\nheavy-light systems. Our method for constructing heavy-light operators exploits\nthe close relation between naive and staggered fermions. The new approach is\ntested on quenched configurations using several staggered actionsn combined\nwith nonrelativistic heavy quarks. The B_s meson kinetic mass, the hyperfine\nand 1P-1S splittings in B_s, and the decay constant f_{B_s} are calculated and\ncompared to previous quenched lattice studies. An important technical detail,\nBayesian curve-fitting, is discussed at length."
    },
    {
        "anchor": "Symmetry, Confinement and the phase diagram of QCD: A general discussion is presented of the possible symmetries responsible for\nconfinement of color and of their evidence in lattice simulations. The\nconsequences on the phase diagram of $QCD$ are also analyzed.",
        "positive": "Unquenched Charmonium with NRQCD - Lattice 2000: We present results from a series of NRQCD simulations of the charmonium\nsystem, both in the quenched approximation and with n_f = 2 dynamical quarks.\nThe spectra show evidence for quenching effects of ~10% in the S- and\nP-hyperfine splittings. We compare this with other systematic effects.\nImproving the NRQCD evolution equation altered the S-hyperfine by as much as 20\nMeV, and we estimate radiative corrections may be as large as 40%."
    },
    {
        "anchor": "A Lattice Study of the Two-photon Decay Widths for Scalar and\n  Pseudo-scalar Charmonium: In this exploratory study, two photon decay widths of pseudo-scalar\n($\\eta_c$) and scalar ($\\chi_{c0}$) charmonium are computed using two ensembles\nof $N_f=2$ twisted mass lattice QCD gauge configurations. The simulation is\nperformed two lattice ensembles with lattice spacings $a=0.067$ fm with size\n$32^3\\times{64}$ and $a=0.085$ fm with size $24^3\\times{48}$, respectively. The\nresults for the decay widths for the two charmonia are obtained which are in\nthe right ballpark however smaller than the experimental ones. Possible reasons\nfor these discrepancies are discussed.",
        "positive": "Localized eigenmodes of the covariant lattice Laplacian: We study numerically the eigenmode spectrum of the covariant lattice\nLaplacian, in the fundamental SU(2) color group representation. It is found\nthat eigenmodes at the lower and upper ends of the spectrum are localized, and\nthat the localization volume scales. In contrast, the eigenmodes of the lattice\nFaddeev-Popov operator are all extended rather than localized (as required for\nconfinement) despite the similarity of the kinetic and Faddeev-Popov operators."
    },
    {
        "anchor": "Status of a minimal composite Higgs theory: We analyze three sets of gauge ensembles in our extended physics program of a\nparticularly important BSM gauge theory with a fermion doublet in the two-index\nsymmetric (sextet) representation of the SU(3) BSM color gauge group. Our\ninvestigations include chiral symmetry breaking $\\rm{(\\chi SB)}$ in the\np-regime and $\\epsilon$-regime, the mass of the composite ${\\rm 0^{++}}$\nscalar, resonance spectroscopy, new physics from gauge anomaly constraints, and\nthe role of stable sextet BSM baryons with Electroweak interactions in dark\nmatter searches. Important new goals include studies of the ${\\rm 0^{++}}$\nscalar entangled with Goldstone dynamics in the p-regime and the\n$\\epsilon$-regime, the resonance spectrum with particular attention to emerging\nLHC signals, like recent hints for diphoton excess at 750 GeV or diboson\nanomalies in the 2 TeV range. All results reported here are preliminary before\njournal publication including some post-conference material for the discussion.",
        "positive": "The $B_{s}\\to \u03bc^{+}\u03bc^{-}\u03b3$ decay rate at large $q^{2}$ from\n  lattice QCD: We determine, by means of lattice QCD calculations, the local form factors\ndescribing the $B_{s}\\to \\mu^{+}\\mu^{-}\\gamma$ decay. For this analysis we make\nuse of the gauge configurations produced by the ETM Collaboration with\n$N_{f}=2+1+1$ flavour of Wilson-Clover twisted-mass fermions at maximal twist.\nTo obtain the $B_{s}$ meson form-factors, we perform simulations for several\nheavy-strange meson masses $m_{H_{s}}$ in the range $m_{H_{s}} \\in [ m_{D_{s}},\n2 m_{D_{s}} ]$, and extrapolate to the physical $B_{s}$ meson point\n$m_{B_{s}}\\simeq 5.367~{\\rm GeV}$ making use of the HQET scaling laws. We cover\nthe region of large di-muon invariant masses $\\sqrt{q^{2}} > 4.16\\,{\\rm GeV}$,\nand use our results to determine the branching fraction for $B_{s}\\to\n\\mu^{+}\\mu^{-}\\gamma$, which has been recently measured by LHCb in the region\n$\\sqrt{q^{2}} > 4.9\\,{\\rm GeV}$. The largest contribution to the uncertainty in\nthe partial branching fractions at values of $\\sqrt{q^{2}} < 4.8\\,{\\rm GeV}$ is\nnow due to resonance and other long-distance effects, including those from\n\"charming penguins\", which we estimate by summing over the contributions from\nthe $J_P=1^-$ charmonium resonances."
    },
    {
        "anchor": "SU(2) Potentials from Large Lattices: We measure accurate values of the inter-quark potentials on a $48^{3}56$\nlattice with SU(2) pure gauge theory at $ \\beta =2.85$. The scale is set by\nextracting the string tension - we obtain ${\\sqrt K}a=0.063(3)$ at $\\beta\n=2.85.$ From a careful study of the small-$R$ potentials in the region 2 GeV $<\nR^{-1} < 5$ GeV, we extract a running coupling constant and estimate the scale\n$\\Lambda _{\\msbar} = 272(24)$ MeV.",
        "positive": "Monopole Loop Distribution and Confinement in SU(2) Lattice Gauge Theory: The abelian-projected monopole loop distribution is extracted from maximal\nabelian gauge simulations. The number of loops of a given length falls as a\npower of the length nearly independent of lattice size. This power increases\nwith $\\beta=4/g^2$, reaching five around $\\beta=2.85$, beyond which loops any\nfinite fraction of the lattice size vanish in the infinite lattice limit,\nsuggesting the continuum theory lacks confinement."
    },
    {
        "anchor": "Magnetic catalysis and inverse catalysis for heavy pions: We investigate the QCD phase diagram for nonzero background magnetic fields\nusing first-principles lattice simulations. At the physical point (in terms of\nquark masses), the thermodynamics of this system is controlled by two opposing\neffects: magnetic catalysis (enhancement of the quark condensate) at low\ntemperature and inverse magnetic catalysis (reduction of the condensate) in the\ntransition region. While the former is known to be robust and independent of\nthe details of the interactions, inverse catalysis arises as a result of a\ndelicate competition, effective only for light quarks. By performing\nsimulations at different quark masses, we determine the pion mass above which\ninverse catalysis does not take place in the transition region anymore. Even\nfor pions heavier than this limiting value - where the quark condensate\nundergoes magnetic catalysis - our results are consistent with the notion that\nthe transition temperature is reduced by the magnetic field. These findings\nwill be useful to guide low-energy models and effective theories of QCD.",
        "positive": "Connected Correlators in Random Geometries: We analyze correlation functions in a toy model of a random geometry\ninteracting with matter. We show that in general the connected correlator will\ncontain a long-range scaling part which is in some sense a remnant of the\ndisconnected part. This result supports the previously conjectured general form\nof correlation functions. We discuss the interplay between matter and geometry\nand the role of the symmetry in the matter sector."
    },
    {
        "anchor": "$B\u03c0$-state contamination in $B$-meson observables: Multi-particle states with additional pions are expected to result in a\nnon-negligible excited-state contamination in lattice simulations. We show that\nheavy meson chiral perturbation theory can be employed to calculate the\ncontamination due to two-particle $B\\pi$ states in various $B$-meson\nobservables like the $B$-meson decay constant and the $BB^*\\pi$ coupling. We\nwork in the static limit and to next-to-leading order in the chiral expansion.\nThe $B\\pi$ states are found to typically overestimate the observables at the\nfew percent level depending on the size of two currently unknown NLO low-energy\ncoefficients. A strategy to independently measure one of them with the 3-point\nfunction of the light axial vector current will be discussed.",
        "positive": "Efficient glueball simulations on anisotropic lattices: Monte Carlo results for the low-lying glueball spectrum using an improved,\nanisotropic action are presented. Ten simulations at lattice spacings ranging\nfrom 0.2 to 0.4 fm and two different anisotropies have been performed in order\ndemonstrate the advantages of using coarse, anisotropic lattices to calculate\nglueball masses. Our determinations of the tensor (2++) and pseudovector (1+-)\nglueball masses are more accurate than previous Wilson action calculations."
    },
    {
        "anchor": "Chiral 1/M^2 corrections to B^(*) -> D^(*) at Zero Recoil in Quenched\n  Chiral Perturbation Theory: Heavy quark effective theory can be used to calculate the values of the\nsemileptonic B^(*) -> D^(*) decays in the limit that the heavy quark masses are\ninfinite. We calculate the lowest order chiral corrections, which are of\nO(1/M^2), from the breaking of heavy quark symmetry at the zero recoil point in\nquenched chiral perturbation theory. These results will aid in the\nextrapolation of quenched lattice calculations from the light quark masses used\non the lattice down to the physical ones.",
        "positive": "The continuum limit of quark number susceptibilities: We report the continuum limit of quark number susceptibilities in quenched\nQCD. Deviations from ideal gas behaviour at temperature T increase as the\nlattice spacing is decreased from T/4 to T/6, but a further decrease seems to\nhave very little effect. The measured susceptibilities are 20% lower than the\nideal gas values, and also 10% below the hard thermal loop (HTL) results. The\noff-diagonal susceptibility is several orders of magnitude smaller than the HTL\nresults. We verify a strong correlation between the lowest screening mass and\nthe susceptibility. We also show that the quark number susceptibilities give a\nreasonable account of the Wroblewski parameter, which measures the strangeness\nyield in a heavy-ion collision."
    },
    {
        "anchor": "Bounds on the Wilson Dirac Operator: New exact upper and lower bounds are derived on the spectrum of the square of\nthe hermitian Wilson Dirac operator. It is hoped that the derivations and the\nresults will be of help in the search for ways to reduce the cost of\nsimulations using the overlap Dirac operator. The bounds also apply to the\nWilson Dirac operator in odd dimensions and are therefore relevant to domain\nwall fermions as well.",
        "positive": "Heavy to light vector meson semileptonic decays: New (preliminary) results for the form factors relevant for the semileptonic\ndecays of heavy pseudoscalar to a light vector meson are presented. In\nparticular, we discuss the form factors for D --> K* and B --> rho modes."
    },
    {
        "anchor": "Flow-based sampling for multimodal distributions in lattice field theory: Recent results have demonstrated that samplers constructed with flow-based\ngenerative models are a promising new approach for configuration generation in\nlattice field theory. In this paper, we present a set of methods to construct\nflow models for targets with multiple separated modes (i.e. theories with\nmultiple vacua). We demonstrate the application of these methods to modeling\ntwo-dimensional real scalar field theory in its symmetry-broken phase. In this\ncontext we investigate the performance of different flow-based sampling\nalgorithms, including a composite sampling algorithm where flow-based proposals\nare occasionally augmented by applying updates using traditional algorithms\nlike HMC.",
        "positive": "Determining the chiral condensate from the distribution of the winding\n  number beyond topological susceptibility: The first two non-trivial moments of the distribution of the topological\ncharge (or gluonic winding number), i.e., the topological susceptibility and\nthe fourth cumulant, can be computed in lattice QCD simulations and exploited\nto constrain the pattern of chiral symmetry breaking. We compute these two\ntopological observables at next-to-leading order in three-flavour Chiral\nPerturbation Theory, and we discuss the role played by the eta propagation in\nthese expressions. For hierarchies of light-quark masses close to the physical\nsituation, we show that the fourth cumulant has a much better sensitivity than\nthe topological susceptibility to the three-flavour quark condensate, and thus\nconstitutes a relevant tool to determine the pattern of chiral symmetry\nbreaking in the limit of three massless flavours. We provide the complete\nformulae for the two topological observables in the isospin limit, and predict\ntheir values in the particular setting of the recent analysis of the RBC/UKQCD\ncollaboration. We show that a combination of the topological susceptibility and\nthe fourth cumulant is able to pin down the three-flavour condensate in a\nparticularly clean way in the case of three degenerate quarks."
    },
    {
        "anchor": "Chiral Corrections to Hyperon Axial Form Factors: We study the complete set of flavor changing hyperon axial current matrix\nelements at small momentum transfer. Using partially quenched heavy baryon\nchiral perturbation theory, we derive the chiral and momentum behavior of the\naxial and induced pseudoscalar form factors. The meson pole contributions to\nthe latter posses a striking signal for chiral physics. We argue that the study\nof hyperon axial matrix elements enables a systematic lattice investigation of\nthe efficacy of three flavor chiral expansions in the baryon sector. This can\nbe achieved by considering chiral corrections to SU(3) symmetry predictions,\nand their partially quenched generalizations. In particular, despite the\npresence of eight unknown low-energy constants, we are able to make\nnext-to-leading order symmetry breaking predictions for two linear combinations\nof axial charges.",
        "positive": "Chirally improving Wilson fermions II. Four-quark operators: In this paper we discuss how the peculiar properties of twisted lattice QCD\nat maximal twist can be employed to set up a consistent computational scheme in\nwhich, despite the explicit breaking of chiral symmetry induced by the presence\nof the Wilson and mass terms in the action, it is possible to completely bypass\nthe problem of wrong chirality and parity mixings in the computation of the\nCP-conserving matrix elements of the $\\Delta S=1,2$ effective weak Hamiltonian\nand at the same time have a positive determinant for non-degenerate quarks as\nwell as full O($a$) improvement in on-shell quantities with no need of\nimproving the lattice action and the operators."
    },
    {
        "anchor": "Generative learning for the problem of critical slowing down in lattice\n  Gross Neveu model: In lattice field theory, Monte Carlo simulation algorithms get highly\naffected by critical slowing down in the critical region, where autocorrelation\ntime increases rapidly. Hence the cost of generation of lattice configurations\nnear the critical region increases sharply. In this paper, we use a Conditional\nGenerative Adversarial Network (C-GAN) for sampling lattice configurations. We\ntrain the C-GAN on the dataset consisting of Hybrid Monte Carlo (HMC) samples\nin regions away from the critical region, i.e., in the regions where the HMC\nsimulation cost is not so high. Then we use the trained C-GAN model to generate\nindependent samples in the critical region. Thus, the overall computational\ncost is reduced. We test our approach for Gross-Neveu model in 1+1 dimension.\nWe find that the observable distributions obtained from the proposed C-GAN\nmodel match with those obtained from HMC simulations, while circumventing the\nproblem of critical slowing down.",
        "positive": "Regularization dependence of the Higgs mass triviality bound: We calculate the triviality bound on the Higgs mass in scalar field theory\nmodels whose global symmetry group $SU(2)_L \\times SU(2)_{\\rm custodial}\n\\approx O(4)$ has been replaced by $O(N)$ and $N$ has been taken to infinity.\nLimits on observable cutoff effects at four percent in several regularized\nmodels with tunable couplings in the bare action yield triviality bounds\ndisplaying a large degree of universality. Extrapolating from $N=\\infty$ to\n$N=4$ we conservatively estimate that a Higgs particle with mass up to\n$0.750~TeV$ and width up to $0.290~TeV$ is realizable without large cutoff\neffects, indicating that strong scalar self interactions in the standard model\nare not ruled out. We also present preliminary numerical results of the\nphysical $N=4$ case for the $F_4$ lattice that are in agreement with the large\n$N$ expectations. Note: The full ps file is also available via anonymous ftp to\nftp.scri.fsu.edu. To get the ps file, ftp to this address and use for username\n\"anonymous\" and for password your name. The file is in the directory pub/vranas\n(to go to that directory type: cd pub/vranas) and is called lat92_proc.ps (to\nget it type: get lat92_proc.ps)"
    },
    {
        "anchor": "A Complete Lattice Technicolor Model: We construct a lattice gauge theory using reduced staggered fermions and\ngauge fields which provides a non-perturbative realization of a {\\it complete}\ntechnicolor model; one which treats both strong and weakly coupled gauge\nsectors on an equal footing. We show that the model is capable of developing a\nHiggs phase at non zero lattice spacing via the formation of fermion\ncondensates. We further show that while the broken symmetry associated with\nthis phase has a vector character in the lattice theory it is realized as an\naxial symmetry in the continuum limit in agreement with the Vafa Witten\ntheorem. We discuss our result in the context of universality",
        "positive": "Topology on the Lattice: We review the method developed in Pisa to determine the topological\nsusceptibility in lattice QCD and present a collection of new and old results\nobtained by the method."
    },
    {
        "anchor": "Lattice regularization of chiral gauge theories to all orders of\n  perturbation theory: In the framework of perturbation theory, it is possible to put chiral gauge\ntheories on the lattice without violating the gauge symmetry or other\nfundamental principles, provided the fermion representation of the gauge group\nis anomaly-free. The basic elements of this construction (which starts from the\nGinsparg-Wilson relation) are briefly recalled and the exact cancellation of\nthe gauge anomaly, at any fixed value of the lattice spacing and for any\ncompact gauge group, is then proved rigorously through a recursive procedure.",
        "positive": "Existence of positive representations for complex weights: The necessity of computing integrals with complex weights over manifolds with\na large number of dimensions, e.g., in some field theoretical settings, poses a\nproblem for the use of Monte Carlo techniques. Here it is shown that very\ngeneral complex weight functions P(x) on R^d can be represented by real and\npositive weights p(z) on C^d, in the sense that for any observable f, <f(x)>_P\n= <f(z)>_p, f(z) being the analytical extension of f(x). The construction is\nextended to arbitrary compact Lie groups."
    },
    {
        "anchor": "Lattice simulation of $(2+1)D$ phonetic solitons and the Renormalization\n  group: The outline of lattice simulations of $(2+1)D$ soliton-propagations in the\nbackground of Weyl spinors is presented. Clifford algebra is applied on\nLuescher's domain decomposition method. The Clifford algebra shows that there\nare loop parts and interpolating surface parts in the Wilson's lattice action.\n  We adopt the Migdal-Kadanoff prescription and the fixed point action in\nmomentum space of Benfatto and Gallavotti, and shows a road map for simulating\nphonetic solitons in materials.\n  Detections of topological anomalies (APS index) in nondestructive testing are\ndiscussed.",
        "positive": "Deflated Multigrid Multilevel Monte Carlo: In lattice QCD, the trace of the inverse of the discretized Dirac operator\nappears in the disconnected fermion loop contribution to an observable. As\nsimulation methods get more and more precise, these contributions become\nincreasingly important. Hence, we consider here the problem of computing the\ntrace $\\mathrm{tr}(D^{-1})$, with $D$ the Dirac operator. The Hutchinson\nmethod, which is very frequently used to stochastically estimate the trace of a\nfunction of a matrix, approximates the trace as the average over estimates of\nthe form $x^{H} D^{-1} x$, with the entries of the vector $x$ following a\ncertain probability distribution. For $N$ samples, the accuracy is\n$\\mathcal{O}(1/\\sqrt{N})$. In recent work, we have introduced multigrid\nmultilevel Monte Carlo: having a multigrid hierarchy with operators $D_{\\ell}$,\n$P_{\\ell}$ and $R_{\\ell}$, for level $\\ell$, we can rewrite the trace\n$\\mathrm{tr}(D^{-1})$ via a telescopic sum with difference-levels, written in\nterms of the aforementioned operators and with a reduced variance. We have seen\nsignificant reductions in the variance and the total work with respect to\nexactly deflated Hutchinson. In this work, we explore the use of exact\ndeflation in combination with the multigrid multilevel Monte Carlo method, and\ndemonstrate how this leads to both algorithmic and computational gains."
    },
    {
        "anchor": "Lattice QCD with mismatched Fermi surfaces: We study two flavor fermions with mismatched chemical potentials in quenched\nlattice QCD. We first consider a large isospin chemical potential, where a\ncharged pion is condensed, and then introduce a small mismatch between the\nchemical potentials of the up quark and the anti-down quark. We find that the\nhomogeneous pion condensate is destroyed by the mismatch of the chemical\npotentials. We also find that the two-point correlation function shows spatial\noscillation, which indicates an inhomogeneous ground state, although it is not\nmassless but massive in the present simulation setup.",
        "positive": "Renormalization-group analysis of the validity of staggered-fermion QCD\n  with the fourth-root recipe: I develop a renormalization-group blocking framework for lattice QCD with\nstaggered fermions. Under plausible, and testable, assumptions, I then argue\nthat the fourth-root recipe used in numerical simulations is valid in the\ncontinuum limit. The taste-symmetry violating terms, which give rise to\nnon-local effects in the fourth-root theory when the lattice spacing is\nnon-zero, vanish in the continuum limit. A key role is played by reweighted\ntheories that are local and renormalizable on the one hand, and that\napproximate the fourth-root theory better and better as the continuum limit is\napproached on the other hand."
    },
    {
        "anchor": "Fractal dimension of the topological charge density distribution in\n  SU(2) lattice gluodynamics: We study the effect of cooling on the spatial distribution of the topological\ncharge density in quenched SU(2) lattice gauge theory with overlap fermions. We\nshow that as the gauge field configurations are cooled, the Hausdorff dimension\nof regions where the topological charge is localized gradually changes from d =\n2..3 towards the total space dimension. Therefore, the cooling procedure\ndestroys some of the essential properties of the topological charge\ndistribution.",
        "positive": "Evidence that centre vortices underpin dynamical chiral symmetry\n  breaking in $\\mathrm{SU}(3)$ gauge theory: The link between dynamical chiral symmetry breaking and centre vortices in\nthe gauge fields of pure $\\mathrm{SU}(3)$ gauge theory is studied using the\noverlap-fermion quark propagator in Lattice QCD. Overlap fermions provide a\nlattice realisation of chiral symmetry and consequently offer a unique\nopportunity to explore the interplay of centre vortices, instantons and\ndynamical mass generation. Simulations are performed on gauge fields featuring\nthe removal of centre vortices, identified through gauge transformations\nmaximising the center of the gauge group. In contrast to previous results using\nthe staggered-fermion action, the overlap-fermion results illustrate a loss of\ndynamical chiral symmetry breaking coincident with vortex removal. This result\nis linked to the overlap-fermion's sensitivity to the subtle manner in which\ninstanton degrees of freedom are compromised through the process of centre\nvortex removal. Backgrounds consisting solely of the identified centre vortices\nare also investigated. After smoothing the vortex-only gauge fields, we observe\ndynamical mass generation on the vortex-only backgrounds consistent within\nerrors with the original gauge-field ensemble following the same smoothing.\nThrough visualizations of the instanton-like degrees of freedom in the various\ngauge-field ensembles, we find evidence of a link between the centre vortex and\ninstanton structure of the vacuum. While vortex removal destabilizes\ninstanton-like objects under ${\\cal\n  O}(a^4)$-improved cooling, vortex-only backgrounds provide gauge-field\ndegrees of freedom sufficient to create instantons upon cooling."
    },
    {
        "anchor": "A Lattice Study of Quark and Glue Momenta and Angular Momenta in the\n  Nucleon: We report a complete calculation of the quark and glue momenta and angular\nmomenta in the proton. These include the quark contributions from both the\nconnected and disconnected insertions. The quark disconnected insertion loops\nare computed with $Z_4$ noise, and the signal-to-noise is improved with\nunbiased subtractions. The glue operator is comprised of gauge-field tensors\nconstructed from the overlap operator. The calculation is carried out on a\n$16^3 \\times 24$ quenched lattice at $\\beta = 6.0$ for Wilson fermions with\n$\\kappa=0.154, 0.155$, and $0.1555$ which correspond to pion masses at $650,\n538$, and $478$~MeV, respectively. The chirally extrapolated $u$ and $d$ quark\nmomentum/angular momentum fraction is found to be $0.64(5)/0.70(5)$, the\nstrange momentum/angular momentum fraction is $0.024(6)/0.023(7)$, and that of\nthe glue is $0.33(6)/0.28(8)$. The previous study of quark spin on the same\nlattice revealed that it carries a fraction of $0.25(12)$ of proton spin. The\norbital angular momenta of the quarks are then obtained from subtracting the\nspin from their corresponding angular momentum components. We find that the\nquark orbital angular momentum constitutes $0.47(13)$ of the proton spin with\nalmost all of it coming from the disconnected insertions.",
        "positive": "Progress in lattice chiral gauge theories: Some key features of continuum chiral fermions are shown to be satisfied by\nthe overlap."
    },
    {
        "anchor": "Covariant gauge on the lattice: a new implementation: We derive a new implementation of linear covariant gauges on the lattice,\nbased on a minimizing functional that can be interpreted as the Hamiltonian of\na spin-glass model in a random external magnetic field. We show that our method\nsolves most problems encountered in earlier implementations, mostly related to\nthe no-go condition formulated by L. Giusti, Nucl. Phys. B 498, 331 (1997). We\ncarry out tests in the SU(2) case in four space-time dimensions. We also\npresent preliminary results for the transverse gluon propagator at different\nvalues of the gauge parameter xi.",
        "positive": "Phenomenology of a Composite Higgs Model: Several UV complete models of physics beyond the Standard Model are currently\nunder scrutiny, their low-energy dynamics being compared with the experimental\ndata from the LHC. Lattice simulations can play a role in these studies by\nproviding a first principles computations of the low-energy constants that\ndescribe this low-energy dynamics. In this work, we study in detail a specific\nmodel recently proposed by Ferretti, and discuss the potential impact of\nlattice calculations."
    },
    {
        "anchor": "Rigorous control of the non-perturbative corrections to the double\n  expansion in $g$ and $g^2\\ln(g)$ for the $\u03c6^4_3$-trajectory in the\n  hierarchical approximation: We study the renormalization invariant trajectory of the\n$\\phi^4$-perturbation of the free field fixed point in the hierarchical\napproximation. We parametrize it by a running $\\phi^4$-coupling $g$ with linear\nstep $\\beta$-function. We rigorously control the non-perturbative corrections\nto finite order approximants from double perturbation theory in $g$ and\n$g^2\\ln(g)$. The construction uses a contraction mapping for the extended\nrenormalization group composed of a hierarchical block spin transformation with\na flow of $g$.",
        "positive": "Meson Decay Constant Predictions of the Valence Approximation to Lattice\n  QCD: We evaluate $f_{\\pi}/ m_{\\rho}$, $f_K/ m_{\\rho}$, $1/f_{\\rho}$, and $\nm_{\\phi}/(f_{\\phi} m_{\\rho})$, extrapolated to physical quark mass, zero\nlattice spacing and infinite volume, for lattice QCD with Wilson quarks in the\nvalence (quenched) approximation. The predicted $m_{\\phi}/(f_{\\phi} m_{\\rho})$\ndiffers from experiment by less than its statistical uncertainty of\napproximately 15\\%. The other three constants are 10\\% to 20\\% below\nexperiment, equivalent to between one and two times the corresponding\nstatistical uncertainties."
    },
    {
        "anchor": "Phase diagram of the three dimensional Thirring model - A Monte Carlo\n  study: Certain approximate solutions of the continuum Schwinger-Dyson Equations\n(SDEs) predict chiral symmetry breaking in the 3d Thirring model when the\nnumber of fermion flavors N_f<4.32 whereas others predict symmetry breaking for\nall N_f. Our results from Monte Carlo simulations with N_f=6, predict a second\norder chiral phase transition. The critical coupling in this case corresponds\nto an ultra-violet fixed point of the renormalization group defining a\nnon-trivial continuum limit. Further, our numerical simulations provide an\nestimate for the critical number of fermion flavors, N_fc \\approx 6.5.",
        "positive": "Spectral Analysis of Excited Nucleons in Lattice QCD with Maximum\n  Entropy Method: We study the mass spectra of excited baryons with the use of the lattice QCD\nsimulations. We focus our attention on the problem of the level ordering\nbetween the positive-parity excited state N'(1440) (the Roper resonance) and\nthe negative-parity excited state N^*(1535). Nearly perfect parity projection\nis accomplished by combining the quark propagators with periodic and\nanti-periodic boundary conditions in the temporal direction. Then we extract\nthe spectral functions from the lattice data by utilizing the maximum entropy\nmethod. We observe that the masses of the N' and N^* states are close for wide\nrange of the quark masses (M_pi=0.61-1.22 GeV), which is in contrast to the\nphenomenological prediction of the quark models. The role of the Wilson\ndoublers in the baryonic spectral functions is also studied."
    },
    {
        "anchor": "$\u03b8$ dependence in $SU(3)$ Yang-Mills theory from analytic\n  continuation: We investigate the topological properties of the $SU(3)$ pure gauge theory by\nperforming numerical simulations at imaginary values of the $\\theta$ parameter.\nBy monitoring the dependence of various cumulants of the topological charge\ndistribution on the imaginary part of $\\theta$ and exploiting analytic\ncontinuation, we determine the free energy density up to the sixth order order\nin $\\theta$, $f(\\theta,T) = f(0,T) + {1\\over 2} \\chi(T) \\theta^2 (1 + b_2(T)\n\\theta^2 + b_4(T) \\theta^4 + O(\\theta^6))$. That permits us to achieve\ndeterminations with improved accuracy, in particular for the higher order\nterms, with control over the continuum and the infinite volume extrapolations.\nWe obtain $b_2=-0.0216(15)$ and $|b_4|\\lesssim 4\\times 10^{-4}$.",
        "positive": "Meson correlation functions at high temperature QCD: $SU(2)_{CS}$\n  symmetry vs. free quarks: We report on the progress of understanding spatial correlation functions in\nhigh temperature QCD. We study isovector meson operators in $N_f=2$ QCD using\ndomain-wall fermions on lattices of $N_s=32$ and different quark masses. It has\npreviously been found that at $\\sim 2T_c$ these observables are not only\nchirally symmetric but in addition approximately $SU(2)_{CS}$ and $SU(4)$\nsymmetric. In this study we increase the temperature up to $5T_c$ and can\nidentify convergence towards an asymptotically free scenario at very high\ntemperatures."
    },
    {
        "anchor": "Large-scale computation of the exponentially expanding universe in a\n  simplified Lorentzian type IIB matrix model: The type IIB matrix model is a conjectured nonperturbative formulation of\nsuperstring theory. Recent studies on the Lorentzian version of the model have\nshown that only three out of nine spatial directions start to expand after some\ncritical time. On the other hand, due to the unbounded action of the Lorentzian\nmodel, one has to introduce infrared (IR) cutoffs in order to make the\npartition function finite. In this work we investigate whether the effects of\nthe IR cutoffs disappear in the infinite volume limit. For that purpose, we\nstudy a simplified model with large matrix size up to $N=256$ by Monte Carlo\nsimulation. First we confirm the exponentially expanding behavior of the\n\"universe\". Then we generalize the form of the IR cutoffs by one parameter, and\nfind that the results become universal in some region of the parameter. It is\nsuggested that the effects of IR cutoffs disappear in this region, which is\nconfirmed also from the studies of Schwinger-Dyson equations.",
        "positive": "The Vacuum Polarization: Power Corrections beyond OPE ?: We compute the vacuum polarization on the lattice using non-perturbatively\nO(a) improved Wilson fermions. The result is compared with the operator product\nexpansion (OPE)."
    },
    {
        "anchor": "Deep Learning of Fermion Sign Fluctuations: We describe a procedure for alleviating the fermion sign problem in which\nphase fluctuations are explicitly subtracted from the Boltzmann factor. Several\nans\\\"atze for fluctuations are designed and compared. In the absence of a\nsufficiently high-quality ansatz, a neural network can be trained to\nparameterize the fluctuations. Demonstrating on the staggered Thirring model in\n$1+1$ dimensions, we examine the performance of this method as deeper neural\nnetworks are used, and in conjunction with the well-studied contour deformation\nmethods.",
        "positive": "Double poles in Lattice QCD with mixed actions: We consider effects resulting from the use of different discretizations for\nthe valence and the sea quarks, considering Wilson and/or Ginsparg--Wilson\nfermions. We assume that such effects appear through scaling violations that\ncan be studied using effective-lagrangian techniques. We show that a double\npole is present in flavor-neutral Goldstone meson propagators, even if the\nflavor non-diagonal Goldstone mesons made out of valence or sea quark have\nequal masses. We then consider some observables known to be anomalously\nsensitive to the presence of a double pole. We find that the double-pole\nenhanced scaling violations may turn out to be rather small in practice."
    },
    {
        "anchor": "Non-equilibrium study of the Chiral Magnetic Effect from real-time\n  simulations with dynamical fermions: We present a real-time lattice approach to study the non-equilibrium dynamics\nof vector and axial charges in $SU(N) \\times U(1)$ gauge theories. Based on a\nclassical description of the non-Abelian and Abelian gauge fields, we include\ndynamical fermions and develop operator definitions for (improved) Wilson and\noverlap fermions that allow us to study real-time manifestations of the axial\nanomaly from first principles. We present a first application of this approach\nto anomalous transport phenomena such as the Chiral Magnetic Effect (CME) and\nChiral Separation Effect (CSE) by studying the dynamics of fermions during and\nafter a $SU(N)$ sphaleron transition in the presence of a $U(1)$ magnetic\nfield. We investigate the fermion mass and magnetic field dependence of the\nsuggested signatures of the CME and CSE and point out some important aspects\nwhich need to be accounted for in the macroscopic description of anomalous\ntransport phenomena.",
        "positive": "Tadpole-improved SU(2) lattice gauge theory: A comprehensive analysis of tadpole-improved SU(2) lattice gauge theory is\nmade. Simulations are done on isotropic and anisotropic lattices, with and\nwithout improvement. Two tadpole renormalization schemes are employed, one\nusing average plaquettes, the other using mean links in Landau gauge.\nSimulations are done with spatial lattice spacings $a_s$ in the range of about\n0.1--0.4 fm. Results are presented for the static quark potential, the\nrenormalized lattice anisotropy $a_t/a_s$ (where $a_t$ is the ``temporal''\nlattice spacing), and for the scalar and tensor glueball masses. Tadpole\nimprovement significantly reduces discretization errors in the static quark\npotential and in the scalar glueball mass, and results in very little\nrenormalization of the bare anisotropy that is input to the action. We also\nfind that tadpole improvement using mean links in Landau gauge results in\nsmaller discretization errors in the scalar glueball mass (as well as in the\nstatic quark potential), compared to when average plaquettes are used. The\npossibility is also raised that further improvement in the scalar glueball mass\nmay result when the coefficients of the operators which correct for\ndiscretization errors in the action are computed beyond tree level."
    },
    {
        "anchor": "A new phase in the Lorentzian type IIB matrix model and the emergence of\n  continuous space-time: The Lorentzian type IIB matrix model is a promising candidate for a\nnon-perturbative formulation of superstring theory. In previous studies, Monte\nCarlo calculations provided interesting results indicating the spontaneous\nbreaking of SO(9) to SO(3) and the emergence of (3+1)-dimensional space-time.\nHowever, an approximation was used to avoid the sign problem, which seemed to\nmake the space-time structure singular. In this talk, we report our results\nobtained by using the complex Langevin method to overcome the sign problem\ninstead of using this approximation. In particular, we discuss the emergence of\ncontinuous space-time in a new phase, which we discovered recently.",
        "positive": "Quark number densities at imaginary chemical potential in $N_f=2$\n  lattice QCD with Wilson fermions and its model analyses: We investigate temperature ($T$) dependence of quark number densities ($n_q$)\nat imaginary and real chemical potential ($\\mu$) by using $N_f = 2$ lattice QCD\nand the hadron resonance gas (HRG) model. Quark number densities are calculated\nat imaginary $\\mu$ with lattice QCD on an $8^2 \\times 16 \\times 4$ lattice with\nthe clover-improved $N_f =2$ Wilson fermion action and the\nrenormalization-group-improved Iwasaki gauge action. The results are consistent\nwith the previous results of the staggered-type quark action. The $n_q$\nobtained are extrapolated to real $\\mu$ by assuming the Fourier series for the\nconfinement region and the polynomial series for the deconfinement region. The\nextrapolated results are consistent with the previous results of the Taylor\nexpansion method for the reweighting factor. The upper bound\n$(\\mu/T)_{\\mathrm{max}}$ of the region where the extrapolation is considered to\nbe reliable is estimated for each temperature $T$ . We test whether $T$\ndependence of nucleon and $\\Delta$-resonance masses can be determined from LQCD\ndata on $n_q$ at imaginary $\\mu$ by using the HRG model. In the test\ncalculation, nucleon and $\\Delta$-resonance masses reduce by about 10% in the\nvicinity of the pseudocritical temperature."
    },
    {
        "anchor": "Flavor-singlet spectrum in multi-flavor QCD: Studying SU(3) gauge theories with increasing number of light fermions is\nrelevant both for understanding the strong dynamics of QCD and for constructing\nstrongly interacting extensions of the Standard Model (e.g. UV completions of\ncomposite Higgs models). In order to contrast these many-flavors strongly\ninteracting theories with QCD, we study the flavor-singlet spectrum as an\ninteresting probe. In fact, some composite Higgs models require the Higgs boson\nto be the lightest flavor-singlet scalar in the spectrum of a strongly\ninteracting new sector with a well defined hierarchy with the rest of the\nstates. Moreover, introducing many light flavors at fixed number of colors can\ninfluence the dynamics of the lightest flavor-singlet pseudoscalar. We present\nthe on-going study of these flavor-singlet channels using multiple\ninterpolating operators on high-statistics ensembles generated by the LatKMI\ncollaboration and we compare results with available data obtained by the\nLattice Strong Dynamics collaboration. For the theory with 8 flavors, the two\ncollaborations have generated configurations that complement each others with\nthe aim to tackle the massless limit using the largest possible volumes.",
        "positive": "Higher angular momentum states of bottomonium in lattice NRQCD: On a cubic lattice the zero-momentum meson states have one of 20 possible\nLambda^{PC} combinations where Lambda labels the irreducible representation of\nthe octahedral group. Each continuum bottomonium state with specific J^{PC}\nquantum numbers is contained within one or more of the lattice Lambda^{PC}\nstates. In this work, bottomonium quark-antiquark operators are constructed for\nall 20 lattice Lambda^{PC} combinations which allows many continuum high\nangular momentum states to be accessible as ground states of their associated\nlattice channels. From a dynamical simulation, realistic results are obtained\nfor S-, P-, D-, F- and G-wave bottomonium states."
    },
    {
        "anchor": "Properties of Overlap and Domain Wall Fermions in the 2+1D Thirring\n  Model: We present some results pertaining to partially quenched formulations of the\noverlap/domain wall operator with the Thirring model in 2+1D. Auxiliary fields\nare generated with a Shamir domain wall approach and measurements of\neigenvalues and condensates are contrasted with different overlap operators.\nThe numerical challenge posed by a non-compact formulation is highlighted, and\nthe effective use of lower accuracy sea fermions is demonstrated.",
        "positive": "The dependence of overlap topological charge density on Wilson mass\n  parameter: In this paper, we analyze the dependence of the topological charge density\nfrom the overlap operator on the Wilson mass parameter in the overlap kernel by\nthe symmetric multi-probing source (SMP) method. We observe that the\nnon-trivial topological objects are removed as the Wilson mass is increased. A\ncomparison of topological charge density calculated by the SMP method using\nfermionic definition with that of gluonic definition by the Wilson flow method\nis shown. A matching procedure for these two methods is used. We find that\nthere is a best match for topological charge density between gluonic definition\nwith varied Wilson flow time and fermionic definition with different Wilson\nmass. By using the matching procedure, the proper flow time of Wilson flow in\nthe calculation of topological charge density can be estimated. As the lattice\nspacing $a$ decreases, the proper flow time also decreases, as expected."
    },
    {
        "anchor": "Finite temperature and confinement along the extra dimensions studied on\n  a five-dimensional U(1) lattice gauge model: In this paper we study the properties of the phase diagram of a simple extra\ndimensional model on the lattice at finite temperature. We consider the\nfive-dimensional pure gauge abelian model with anisotropic couplings which at\nzero temperature exhibits a new interesting phase, the layer phase. This phase\nis characterized by a massless photon living on the four dimensional subspace\nand confinement along the extra dimension. We show that, as long as the\ntemperature takes a non zero value the aforementioned layer phase disappears.\nIt would be equivalent to assume that at finite temperature the\nhigher-dimensional lattice model loses any feature of the layered structure due\nto the deconfinement which opens up the interactions between the\nthree-dimensional subspaces at finite temperature.",
        "positive": "Symanzik Improvement with Dynamical Charm: A 3+1 Scheme for Wilson\n  Quarks: We discuss the problem of lattice artefacts in QCD simulations enhanced by\nthe introduction of dynamical charmed quarks. In particular, we advocate the\nuse of a massive renormalization scheme with a close to realistic charm mass.\nTo maintain O(a) improvement for Wilson type fermions in this case we define a\nfinite size scheme and carry out a nonperturbative estimation of the clover\ncoefficient $c_\\mathrm{sw}$. It is summarized in a fit formula\n$c_\\mathrm{sw}(g_0^2)$ that defines an improved action suitable for future\ndynamical charm simulations."
    },
    {
        "anchor": "Nature of the finite temperature transition in QCD with strange quark: The finite temperature transition in QCD is studied using Wilson quarks for\nthe cases of $N_F=2$, 3 and 2+1. For $N_F=2$ the transition is smooth in the\nchiral limit on both $\\nt=4$ and 6 lattices. For $N_F=3$, clear two state\nsignals are observed for $\\beta\\leq4.7$ on $8^2\\times10 \\times4$ and\n$12^3\\times4$ lattices, which implies the transition is first order for $m_q\n\\simm{<} 140$ MeV. For $N_F=2+1$ we study two cases of $m_s \\simeq 150$ and 400\nMeV with $m_u=m_d \\simeq 0$. In contrast to a previous result with staggered\nquarks, two state signals are clearly observed for both cases, suggesting a\nfirst order QCD phase transition in the real world.",
        "positive": "The Staggered Fermion for the Gross-Neveu Model at Non-zero Temperature\n  and Density: The 2+1d Gross-Neveu model with finite density and finite temperature are\nstudied by the staggered fermion discretization. The kinetic part of this\nstaggered fermion in momentum space is used to build the relation between the\nstaggered fermion and Wilson-like fermion. In the large Nf limit (the number Nf\nof staggered fermion flavors), the chiral condensate and fermion density are\nsolved from the gap equation in momentum space, and thus the phase diagram of\nfermion coupling, temperature and chemical potential are obtained. Moreover, an\nanalytic formula for the inverse of the staggered fermion matrix are given\nexplicitly, which can be calculated easily by parallelization. The\ngeneralization to the 1+1d and 3+1d cases are also considered."
    },
    {
        "anchor": "Exploring the chiral regime with dynamical overlap fermions: I report the status of the dynamical overlap fermion project by the JLQCD and\nTWQCD collaborations. So far, the simulations have been completed with two\nflavors of overlap sea quarks in a wide range of sea quark mass corresponding\nthe $p$-regime and the $\\epsilon$-regime on a $16^3\\times 32$ lattice at\n$a=$0.12 fm. More recently, runs with 2+1 flavors of sea quarks have also\nstarted. This talk mainly discusses the physics results on the $N_f=2$ lattice\nafter describing the lattice formulation and algorithms.",
        "positive": "Scaling behavior at the tricritical point in the fermion-gauge-scalar\n  model: We investigate a strongly coupled U(1) gauge theory with fermions and scalars\non the lattice and analyze whether the continuum limit might be a\nrenormalizable theory with dynamical mass generation. Most attention is paid to\nthe phase with broken chiral symmetry in the vicinity of the tricritical point\nfound in the model. There we investigate the scaling of the masses of the\ncomposite fermion and of some bosonic bound states. As a by-product we confirm\nthe mean-field exponents at the endpoint in the U(1)-Higgs model, by analyzing\nthe scaling of the Fisher zeros."
    },
    {
        "anchor": "Progress on a canonical finite density algorithm: We test the finite density algorithm in the canonical ensemble which combines\nthe HMC update with the accept/reject step according to the ratio of the\nfermion number projected determinant to the unprojected one as a way of\navoiding the determinant fluctuation problem. We report our preliminary results\non the Polyakov loop in different baryon number sectors which exhibit\ndeconfinement transitions on small lattices. The largest density we obtain\naround $T_c$ is an order of magnitude larger than that of nuclear matter. From\nthe conserved vector current, we calculate the quark number and verify that the\nmixing of different baryon sectors is small.",
        "positive": "Real-time quantum calculations of phase shifts using wave packet time\n  delays: We present a method to extract the phase shift of a scattering process using\nthe real-time evolution in the early and intermediate stages of the collision\nin order to estimate the time delay of a wave packet. This procedure is\nconvenient when using noisy quantum computers for which the asymptotic\nout-state behavior is unreachable. We demonstrate that the challenging Fourier\ntransforms involved in the state preparation and measurements can be\nimplemented in $1+1$ dimensions with current trapped ion devices and IBM\nquantum computers. We compare quantum computation of the time delays obtained\nin the one-particle quantum mechanics limit and the scalable quantum field\ntheory formulation with accurate numerical results. We discuss the finite\nvolume effects in the Wigner formula connecting time delays to phase shifts.\nThe results reported involve two- and four-qubit calculations, and we discuss\nthe possibility of larger scale computations in the near future."
    },
    {
        "anchor": "Finite-Volume QED Corrections to Decay Amplitudes in Lattice QCD: We demonstrate that the leading and next-to-leading finite-volume effects in\nthe evaluation of leptonic decay widths of pseudoscalar mesons at $O(\\alpha)$\nare universal, i.e. they are independent of the structure of the meson. This is\nanalogous to a similar result for the spectrum but with some fundamental\ndifferences, most notably the presence of infrared divergences in decay\namplitudes. The leading non-universal, structure-dependent terms are of\n$O(1/L^2)$ (compared to the $O(1/L^3)$ leading non-universal corrections in the\nspectrum). We calculate the universal finite-volume effects, which requires an\nextension of previously developed techniques to include a dependence on an\nexternal three-momentum (in our case, the momentum of the final state lepton).\nThe result can be included in the strategy proposed in\nRef.\\,\\cite{Carrasco:2015xwa} for using lattice simulations to compute the\ndecay widths at $O(\\alpha)$, with the remaining finite-volume effects starting\nat order $O(1/L^2)$. The methods developed in this paper can be generalised to\nother decay processes, most notably to semileptonic decays, and hence open the\npossibility of a new era in precision flavour physics.",
        "positive": "PLQCD library for Lattice QCD on multi-core machines: PLQCD is a stand-alone software library developed under PRACE for lattice\nQCD. It provides an implementation of the Dirac operator for Wilson type\nfermions and few efficient linear solvers. The library is optimized for\nmulti-core machines using a hybrid parallelization with OpenMP+MPI. The main\nobjectives of the library is to provide a scalable implementation of the Dirac\noperator for efficient computation of the quark propagator. In this\ncontribution, a description of the PLQCD library is given together with some\nbenchmark results."
    },
    {
        "anchor": "Finite-density QCD, $\\mathcal{PT}$ symmetry, and exotic phases: We study the phase structure of effective models of finite-density QCD using\nanalytic and lattice simulation techniques developed for the study of\nnon-Hermitian and $\\mathcal{PT}$-symmetric QFTs. Finite-density QCD is\nsymmetric under the combined operation of the charge and complex conjugation\noperators $\\mathcal{CK}$, which falls into the class of so-called generalized\n$\\mathcal{PT}$ symmetries. We show that $\\mathcal{PT}$-symmetric quantum field\ntheories can support patterned ground-state field configurations in the\nvicinity of a critical endpoint. We apply our methods to a lattice heavy quark\nmodel at nonzero chemical potential that displays patterning behavior for a\nrange of parameters. We derive a simple approximate criterion for the formation\nof these patterns, which can be used with lattice results.",
        "positive": "Pseudoscalar decay constants, light-quark masses, and B_K from\n  mixed-action lattice QCD: We present updated results for the leptonic decay constants f_pi and f_K, the\nlight u, d, and s-quark masses, and the neutral kaon mixing parameter B_K from\nmixed-action lattice simulations with staggered sea quarks and domain-wall\nvalence quarks. We use the publicly-available 2+1 flavor MILC asqtad-improved\nstaggered gauge configurations with multiple light sea-quark masses and three\nlattice spacings, and compute the kaon mixing matrix element with several\npartially-quenched valence-quark masses. We then extrapolate to the physical\nlight-quark masses and the continuum using partially-quenched chiral\nperturbation theory formulated for mixed-action lattice simulations. For B_K we\nmatch the lattice four-fermion operator to the continuum using the\nnonperturbative method of Rome-Southampton. Our new results benefit from two\nsignificant improvements over our published work: (1) we have added a third\nlattice spacing of a~0.06 fm to better control the continuum extrapolation, and\n(2) we have implemented a new lattice renormalization scheme (the\nRI/SMOM_{gamma_mu} scheme developed by Sturm et al.) that suppresses\nchiral-symmetry breaking and other infrared effects and, in practice, also\nshrinks the size of the 1-loop perturbative coefficient needed to match to the\ncontinuum MS-bar scheme. When combined with the use of volume-averaged momentum\nsources and twisted-boundary conditions, this significantly reduces the\nsystematic uncertainty in the renormalization factor Z_{B_K}."
    },
    {
        "anchor": "Non-Standard Physics in Leptonic and Semileptonic Decays of Charmed\n  Mesons: Recent measurements of the branching fraction for D_s -> l nu disagree with\nthe Standard Model expectation, which relies on calculations of $f_{D_s}$ from\nlattice QCD. This paper uses recent preliminary measurements from CLEO and a\nnew preliminary lattice-QCD result from this conference to update the\nsignificance of the discrepancy. The \"f_{D_s} puzzle\" stands now at 3.5sigma,\nwith sigma predominantly from the statistical uncertainty of the experiments.\nNew physics scenarios that could solve the puzzle would also lead to\nnon-Standard amplitudes mediating the semileptonic decays D -> K l nu. This\npaper shows where the new amplitudes enter the differential rate and outlines\nwhere lattice QCD calculations are needed to confront recent and forthcoming\nmeasurements.",
        "positive": "Large N QCD on the lattice -- A review of recent results in the\n  fermionic sector: It is possible to numerically solve QCD in the planar limit using standard\nnumerical techniques on existing computer clusters. The basic ideas behind the\ncomputational strategy an recent numerical results in the fermionic sector of\nlarge N QCD are reviewed."
    },
    {
        "anchor": "High temperature critical O(N) field models by LCE series: The critical properties of renormalizable O(N) field models are determined by\nmeans of the high order ($\\geq 18$) behaviour of convergent linked cluster\nseries on finite temperature lattices. It is shown that those models become\nweakly coupled at the phase transition. The critical exponents agree to those\nof the corresponding superrenormalizable 3-dimensional models. Concerning\ncritical amplitudes and subcritical behaviour, corrections induced by\nrenormalizable couplings are measurable.",
        "positive": "Imaginary Chemical Potential Approach for the Pseudo-Critical Line in\n  the QCD Phase Diagram with Clover-Improved Wilson Fermions: The QCD phase diagram is studied in the lattice QCD simulation with the\nimaginary chemical potential approach. We employ a clover-improved Wilson\nfermion action of two-flavors and a renormalization-group improved gauge\naction, and perform the simulation at an intermediate quark mass on a\n$8^3\\times 4$ lattice. The QCD phase diagram in the imaginary chemical\npotential $\\mu_I$ region is investigated by performing the simulation for more\nthan 150 points on the $(\\beta,\\mu_I)$ plane. We find that the Roberge-Weiss\nphase transition at $\\mu_I/T=\\pi/3$ is first order and its endpoint is second\norder, which are identified by the phase of the Polyakov loop. We determine the\npseudo-critical line from the susceptibility of the Polyakov loop modulus. We\nfind a clear deviation from a linear dependence of the pseudo-critical line on\n$\\mu_I^2$."
    },
    {
        "anchor": "Large N lattice gauge theory: Wilson loops in large N gauge theory exhibit a weak to strong coupling\ntransition as the loop is dilated. A multiplicative matrix model captures the\nuniversal behavior associated with this transition. A universal scaling\nfunction is obtained in a double scaling limit. Numerical studies show that\nboth large N QCD in three dimensions and the SU(N) principal chiral model in\ntwo dimensions are in the same universality class.",
        "positive": "Renormalization and topological susceptibility on the lattice: SU(2)\n  Yang-Mills theory: The renormalization functions involved in the determination of the\ntopological susceptibility in the SU(2) lattice gauge theory are extracted by\ndirect measurements, without relying on perturbation theory. The determination\nexploits the phenomenon of critical slowing down to allow the separation of\nperturbative and non-perturbative effects. The results are in good agreement\nwith perturbative computations."
    },
    {
        "anchor": "A High Precision Study of the QQ(bar) Potential from Wilson Loops in the\n  Regime of String Breaking: For lattice QCD with two sea quark flavours we compute the static quark\nantiquark potential V(R) in the regime where string breaking is expected. In\norder to increase statistics, we make full use of the lattice information by\nincluding all lattice vectors R to any possible lattice separation in the\ninfrared regime. The corresponding paths between the lattice points are\nconstructed by means of a generalized Bresenham algorithm as known from\ncomputer graphics. As a results we achieve a determination of the unquenched\npotential in the range .8 to 1.5 fm with hitherto unknown precision.\nFurthermore, we demonstrate some error reducing methods for the evaluation of\nthe transition matrix element between two- and four-quark states.",
        "positive": "Vacuum alignment and lattice artifacts: When a subgroup of the flavor symmetry group of a gauge theory is weakly\ncoupled to additional gauge fields, the vacuum tends to align such that the\ngauged subgroup is unbroken. At the same time, the lattice discretization\ntypically breaks the flavor symmetry explicitly, and can give rise to new\nlattice-artifact phases with spontaneously broken symmetries. We discuss the\ninterplay of these two phenomena, using chiral lagrangian techniques. Our first\nexample is two-flavor Wilson QCD coupled to electromagnetism. We also consider\nexamples of theories with staggered fermions, and demonstrate that recent\nclaims in the literature based on the use of staggered fermions are incorrect."
    },
    {
        "anchor": "Influence of the Measure on Simplicial Quantum Gravity in Four\n  Dimensions: We investigate the influence of the measure in the path integral for\nEuclidean quantum gravity in four dimensions within the Regge calculus. The\naction is bounded without additional terms by fixing the average lattice\nspacing. We set the length scale by a parameter $\\beta$ and consider a scale\ninvariant and a uniform measure. In the low $\\beta$ region we observe a phase\nwith negative curvature and a homogeneous distribution of the link lengths\nindependent of the measure. The large $\\beta$ region is characterized by\ninhomogeneous link lengths distributions with spikes and positive curvature\ndepending on the measure.",
        "positive": "Lowest eigenvalues of the Dirac operator for two color QCD at finite\n  density: We investigate the eigenvalue spectrum of the staggered Dirac matrix in full\nQCD with two colors and finite chemical potential. Along the strong-coupling\naxis up to the temperature phase transition, the low-lying Dirac spectrum is\nwell described by random matrix theory (RMT) and exhibits universal behavior.\nThe situation is discussed in the chirally symmetric phase and no universality\nis seen for the microscopic spectral density."
    },
    {
        "anchor": "Charmed baryon spectroscopy and light flavour symmetry from lattice QCD: We determine the ground state and first excited state masses of singly and\ndoubly charmed spin 1/2 and 3/2 baryons with positive and negative parity.\nConfigurations with $N_f=2+1$ non-perturbatively improved Wilson-clover\nfermions were employed, with the same quark action also being used for the\nvalence quarks, including the charm. The spectrum is calculated for pion masses\nin the range $M_\\pi \\sim 259-460$ MeV at a lattice spacing $a\\sim 0.075$ fm.\nFinite volume effects are studied comparing lattices with two different linear\nspatial extents ($1.8\\,{\\rm fm}$ and $2.4\\,{\\rm fm}$). The physical point is\napproached from the SU(3) limit keeping the flavour averaged light quark mass\nfixed. The baryon masses are extrapolated using expansions in the strange-light\nquark mass difference. Most particles fall into the expected SU(3) multiplets\nwith well constrained extrapolations, the exceptions having a possibly more\ncomplex internal structure. Overall agreement is found with experiment for the\nmasses and splittings of the singly charmed baryons. As part of the calculation\nan analysis of the lower lying charmonium, $D$ and $D_s$ spectra was performed\nin order to assess discretisation errors. The gross spectra are reproduced,\nincluding the $D^*_{s0}$, $D_{s1}$ and $D_1$ mesons, while at this single\nlattice spacing hyperfine splittings come out $10-20$ MeV too low.",
        "positive": "Heavy Quarks on the Lattice: This lecture describes the treatment of heavy quarks in lattice QCD by\nimplementing the Isgur-Wise limit. The method is briefly discussed, and some of\nthe special features of the resulting theory are highlighted. We emphasize\nissues of the renormalization of the effective theory. The formulation permits\na calculation of heavy quark processes even when the momentum transfers are\nmuch larger than the inverse lattice spacing. Applications include\nsemi-leptonic heavy quark decay and scattering processes, including the\ncomputation of the nonperturbative part of the Isgur-Wise universal function."
    },
    {
        "anchor": "Finite Density $QED_{1+1}$ Near Lefschetz Thimbles: One strategy for reducing the sign problem in finite-density field theories\nis to deform the path integral contour from real to complex fields. If the\ndeformed manifold is the appropriate combination of Lefschetz thimbles -- or\nsomewhat close to them -- the sign problem is alleviated. Gauge theories lack a\nwell-defined thimble decomposition, and therefore it is unclear how to carry\nout a generalized thimble method. In this paper we discuss some of the\nconceptual issues involved by applying this method to $QED_{1+1}$ at finite\ndensity, showing that the generalized thimble method yields correct results\nwith less computational effort than standard methods.",
        "positive": "Four Quarks from Lattice to the Continuum: A continuum extrapolation of static four- and two-quark energies calculated\nin quenched SU(2) is done based on Sommer's method of setting the scale. A\nmodel for four-quark energies with explicit gluonic degrees of freedom removed\nis fitted to these energies and the behavior of the parameters of the model is\ninvestigated."
    },
    {
        "anchor": "Variational approach to $N$-body interactions in finite volume: We explore variational approach to the finite-volume $N$-body problem. The\ngeneral formalism for N non-relativistic spinless particles interacting with\nperiodic pair-wise potentials yields N-body secular equations. The solutions\ndepend on the infinite-volume N-body wave functions. Given that the\ninfinite-volume N-body dynamics may be solved by the standard Faddeev approach,\nthe variational N-body formalism can provide a convenient numerical framework\nfor finding discrete energy spectra in periodic lattice structures.",
        "positive": "Monopoles at Finite Volume and Temperature in SU(2) Lattice Gauge Theory: We resolve a discrepancy between the SU(2) spacial string tension at finite\ntemperature, and the value obtained by monopoles in the maximum Abelian gauge.\nPrevious work had incorrectly omitted a term due to Dirac sheets. When this\nterm is included, the monopole and full SU(2) determinations of the spacial\nstring tension agree to within the statistical errors of the monopole\ncalculation."
    },
    {
        "anchor": "Accelerating Lattice QCD Multigrid on GPUs Using Fine-Grained\n  Parallelization: The past decade has witnessed a dramatic acceleration of lattice quantum\nchromodynamics calculations in nuclear and particle physics. This has been due\nto both significant progress in accelerating the iterative linear solvers using\nmulti-grid algorithms, and due to the throughput improvements brought by GPUs.\nDeploying hierarchical algorithms optimally on GPUs is non-trivial owing to the\nlack of parallelism on the coarse grids, and as such, these advances have not\nproved multiplicative. Using the QUDA library, we demonstrate that by exposing\nall sources of parallelism that the underlying stencil problem possesses, and\nthrough appropriate mapping of this parallelism to the GPU architecture, we can\nachieve high efficiency even for the coarsest of grids. Results are presented\nfor the Wilson-Clover discretization, where we demonstrate up to 10x speedup\nover present state-of-the-art GPU-accelerated methods on Titan. Finally, we\nlook to the future, and consider the software implications of our findings.",
        "positive": "Perturbation Theory at Finite Extent of Fifth Dimension for Vacuum\n  Overlap Formula of Chiral Determinant -- Continuum Limit Case --: Taking into account of the boundary condition in the fifth direction which is\nderived from the lattice Wilson fermion, we develop a theory of\nfive-dimensional fermion with kink-like and homogeneous masses in finite extent\nof the fifth dimension. The boundary state wave functions are constructed\nexplicitly and the would-be vacuum overlap is expanded by using the propagator\nof the theory. The subtraction is performed unambiguously at the finite extent\nwith the help of the dimensional regularization. Then the limit of the infinite\nextent is evaluated. The consistent anomaly in four dimensional theory is\nfinitely obtained. Each contribution to the vacuum polarization is vector-like.\nIt is the lack of the massless mode in the fermion with negative homogeneous\nmass that leads to the correct chiral normalization. Gauge noninvariant piece\nremains due to the breaking of the boundary condition by the dimensional\nregularization."
    },
    {
        "anchor": "Rare decay B -> K ll form factors from lattice QCD: We calculate, for the first time using unquenched lattice QCD, form factors\nfor the rare decay B -> Kll in and beyond the Standard Model. Our lattice QCD\ncalculation utilizes a nonrelativistic QCD formulation for the b valence\nquarks, the highly improved staggered quark formulation for the light valence\nquarks, and employs the MILC 2+1 asqtad ensembles. The form factor results,\nbased on the z expansion, are valid over the full kinematic range of q^2. We\nconstruct the ratios f0/f+ and fT/f+, which are useful in constraining new\nphysics and verifying effective theory form factor symmetry relations. We also\ndiscuss the calculation of Standard Model observables.",
        "positive": "Canonical simulations of supersymmetric SU(N) Yang-Mills quantum\n  mechanics: The fermion loop formulation naturally separates partition functions into\ntheir canonical sectors. Here we discuss various strategies to make use of this\nfor supersymmetric SU(N) Yang-Mills quantum mechanics obtained from dimensional\nreduction in various dimensions and present numerical results for the separate\ncanonical sectors with fixed fermion numbers. We comment on potential problems\ndue to the sign of the contributions from the fermions and due to flat\ndirections."
    },
    {
        "anchor": "Constraining the QCD phase diagram at finite temperature and density: Neither the chiral limit nor finite baryon density can be simulated directly\nin lattice QCD, which severely limits our understanding of the QCD phase\ndiagram. In this review I collect results for the phase structure in an\nextended parameter space of QCD, with varying numbers of flavours, quark\nmasses, colours, lattice spacings, imaginary and isospin chemical potentials.\nSuch studies help in understanding the underlying symmetries and degrees of\nfreedom, and are beginning to provide a consistent picture constraining the\npossibilities for the physical phase diagram.",
        "positive": "Measuring charged particle polarizabilities on the lattice without\n  background fields: We show how to compute electromagnetic polarizabilities of charged hadrons\nwithout the use of background fields in lattice QCD. The low-energy behavior of\nthe Compton scattering amplitude is matched to matrix elements of\ncurrent-current correlation functions on the lattice. Working in momentum\nspace, formulas for electric polarizability ($\\alpha_E$) and magnetic\npolarizability ($\\beta_M$) are derived for both charged pion and proton.\nLattice four-point correlation functions are constructed from quark and gluon\nfields to be used in Monte-Carlo simulations. We also draw attention to the\npotential of four-point functions as a multi-purpose tool for hadron structure."
    },
    {
        "anchor": "Decay constants from twisted mass QCD: We present results for chiral extrapolations of the mass and decay constants\nof the rho meson. The data sets used are the nf=2 unquenched gauge\nconfigurations generated with twisted mass fermions by the European Twisted\nMass Collaboration. We describe a calculation of three decay constants in\ncharmonium and explain why they are required.",
        "positive": "Lattice QCD at the physical point meets SU(2) chiral perturbation theory: We perform a detailed, fully-correlated study of the chiral behavior of the\npion mass and decay constant, based on 2+1 flavor lattice QCD simulations.\nThese calculations are implemented using tree-level, O(a)-improved Wilson\nfermions, at four values of the lattice spacing down to 0.054 fm and all the\nway down to below the physical value of the pion mass. They allow a sharp\ncomparison with the predictions of SU(2) chiral perturbation theory (\\chi PT)\nand a determination of some of its low energy constants. In particular, we\nsystematically explore the range of applicability of NLO SU(2) \\chi PT in two\ndifferent expansions: the first in quark mass (x-expansion), and the second in\npion mass (\\xi-expansion). We find that these expansions begin showing signs of\nfailure around M_\\pi=300 MeV for the typical percent-level precision of our\nN_f=2+1 lattice results. We further determine the LO low energy constants\n(LECs), F=88.0 \\pm 1.3\\pm 0.3 and B^\\msbar(2 GeV)=2.58 \\pm 0.07 \\pm 0.02 GeV,\nand the related quark condensate, \\Sigma^\\msbar(2 GeV)=(271\\pm 4\\pm 1 MeV)^3,\nas well as the NLO ones, l_3=2.5 \\pm 0.5 \\pm 0.4 and l_4=3.8 \\pm 0.4 \\pm 0.2,\nwith fully controlled uncertainties. We also explore the NNLO expansions and\nthe values of NNLO LECs. In addition, we show that the lattice results favor\nthe presence of chiral logarithms. We further demonstrate how the absence of\nlattice results with pion masses below 200 MeV can lead to misleading results\nand conclusions. Our calculations allow a fully controlled, ab initio\ndetermination of the pion decay constant with a total 1% error, which is in\nexcellent agreement with experiment."
    },
    {
        "anchor": "Adaptive Aggregation-based Domain Decomposition Multigrid for Twisted\n  Mass Fermions: The Adaptive Aggregation-based Domain Decomposition Multigrid method\n(arXiv:1303.1377) is extended for two degenerate flavors of twisted mass\nfermions. By fine-tuning the parameters we achieve a speed-up of the order of\nhundred times compared to the conjugate gradient algorithm for the physical\nvalue of the pion mass. A thorough analysis of the aggregation parameters is\npresented, which provides a novel insight into multigrid methods for lattice\nQCD independently of the fermion discretization.",
        "positive": "Bit Level Correlations in Some Pseudorandom Number Generators: We present results of extensive bit level tests on some pseudorandom number\ngenerators which are commonly used in physics applications. The generators have\nfirst been tested with an extended version of the $d$-tuple test. Second, we\nhave developed a novel {\\it cluster test} where a physical analogy of the\nbinary numbers with the two dimensional Ising model has been utilized. We\ndemonstrate that the new test is rather powerful in finding periodic\ncorrelations on bit level. Results of both test methods are presented for each\nbit of the output of the generators. Some generators exhibit clear bit level\ncorrelations but we find no evidence of discernible correlations for\ngenerators, which have recently produced systematic errors in Monte Carlo\nsimulations."
    },
    {
        "anchor": "Quenched Chiral Behavior of Hadrons with Overlap Fermions: We study the quenched chiral behavior of hadrons with the pseudoscalar mass\nas low as $\\approx 280$ MeV. We look for quenched chiral logs in the pion mass,\ndetermine the renormalized quark mass, and observe quenched artifacts in the\n$a_0$ and $N^*$ propagators. The calculation is done on a quenched lattice of\nsize $20^4$ and $a = 0.148(2)$ fm using overlap fermions and an improved gauge\naction.",
        "positive": "Lattice QCD and baryon-baryon interactions: HAL QCD method: In this article, we review the HAL QCD method to investigate baryon-baryon\ninteractions such as nuclear forces in lattice QCD. We first explain our\nstrategy in detail to investigate baryon-baryon interactions by defining\npotentials in field theories such as QCD. We introduce the Nambu-Bethe-Salpeter\n(NBS) wave functions in QCD for two baryons below the inelastic threshold. We\nthen define the potential from NBS wave functions in terms of the derivative\nexpansion, which is shown to reproduce the scattering phase shifts correctly\nbelow the inelastic threshold. Using this definition, we formulate a method to\nextract the potential in lattice QCD. Secondly, we discuss pros and cons of the\nHAL QCD method, by comparing it with the conventional method, where one\ndirectly extracts the scattering phase shifts from the finite volume energies\nthrough the L\\\"uscher's formula. We give several theoretical and numerical\nevidences that the conventional method combined with the naive plateau fitting\nfor the finite volume energies in the literature so far fails to work on\nbaryon-baryon interactions due to contaminations of elastic excited states. On\nthe other hand, we show that such a serious problem can be avoided in the HAL\nQCD method by defining the potential in an energy-independent way. We also\ndiscuss systematics of the HAL QCD method, in particular errors associated with\na truncation of the derivative expansion. Thirdly, we present several results\nobtained from the HAL QCD method, which include (central) nuclear force, tensor\nforce, spin-orbital force, and three nucleon force. We finally show the latest\nresults calculated at the nearly physical pion mass, $m_\\pi \\simeq 146$ MeV,\nincluding hyperon forces which lead to form $\\Omega\\Omega$ and $N\\Omega$\ndibaryons."
    },
    {
        "anchor": "Interaction potentials for two-particle states with non-zero total\n  momenta in lattice QCD: In this study, we extend the HAL QCD method to a case where a total momentum\nof a two-particle system is non-zero and apply it to the $I=2$ S-wave $\\pi\\pi$\nscattering in order to confirm its validity. We derive a fundamental relation\nof an energy-independent non-local potential defined in the center of mass\nframe with NBS wave functions in a laboratory frame. Based on the relation, we\npropose the time-dependent method to extract potentials, often used in practice\nfor the HALQCD method in the center of mass frame. For numerical simulations in\nthe $I=2$ $\\pi\\pi$ system, we employ (2+1)-flavor gauge configurations on a\n$32^3 \\times 64$ lattice at the lattice spacing $a \\approx 0.0907$ fm and\n$m_{\\pi} \\approx 700$ MeV. Both effective leading order (LO) potentials and\ncorresponding phase shifts obtained in laboratory frames agree with those\nobtained in the center-of-mass frame by the conventional HAL QCD method within\nsomewhat larger statistical errors. In addition, we observe a consistency in\nscattering phase shifts between ours and results by the finite-volume method as\nwell. The HAL QCD method with non-zero total momenta, established in this\nstudy, brings more flexibility to the HAL QCD method, which enables us to\nhandle systems having the same quantum numbers with a vacuum or to access\nenergy regions prohibited in the center of mass frame.",
        "positive": "Scale setting in lattice QCD: The principles of scale setting in lattice QCD as well as the advantages and\ndisadvantages of various commonly used scales are discussed. After listing\ncriteria for good scales, I concentrate on the main presently used ones with an\nemphasis on scales derived from the Yang-Mills gradient flow. For these I\ndiscuss discretisation errors, statistical precision and mass effects. A short\nreview on numerical results also brings me to an unpleasant disagreement which\nremains to be explained."
    },
    {
        "anchor": "Bosonization and Cluster Updating of Lattice Fermions: A lattice fermion model is formulated in Fock space using the Jordan-Wigner\nrepresentation for the fermion creation and annihilation operators. The\nresulting path integral is a sum over configurations of lattice site occupation\nnumbers $n(x,t) = 0,1$ which may be viewed as bosonic Ising-like variables.\nHowever, as a remnant of Fermi statistics a nonlocal sign factor arises for\neach configuration. When this factor is included in measured observables the\nbosonic occupation numbers interact locally, and one can use efficient cluster\nalgorithms to update the bosonized variables.",
        "positive": "A guide to light-cone PDFs from Lattice QCD: an overview of approaches,\n  techniques and results: Within the theory of Quantum Chromodynamics (QCD), the rich structure of\nhadrons can be quantitatively characterized, among others, using a basis of\nuniversal non-perturbative functions: parton distribution functions (PDFs),\ngeneralized parton distributions (GPDs), transverse-momentum dependent\ndistributions (TMDs) and distribution amplitudes (DAs). For more than half a\ncentury, there has been a joint experimental and theoretical effort to obtain\nthese partonic functions. However, the complexity of the strong interactions\nhas placed severe limitations, and first-principle results on the distributions\nwas extracted mostly from their moments computed in Lattice QCD. Recently,\nbreakthrough ideas changed the landscape and several approaches were proposed\nto access the distributions themselves on the lattice.\n  In this paper, we review in considerable detail approaches directly related\nto partonic distributions. We highlight a recent idea proposed by X. Ji on\nextracting quasi-distributions that spawned renewed interest in the whole field\nand sparked the largest amount of numerical studies of Lattice QCD. We discuss\ntheoretical and practical developments, including challenges that had to be\novercome, with some yet to be handled. We also review numerical results,\nincluding a discussion based on evolving understanding of the underlying\nconcepts and theoretical and practical progress. Particular attention is given\nto important aspects that validated the quasi-distribution approach, such as\nrenormalization, matching to light-cone distributions and lattice techniques.\n  In addition to a thorough discussion of quasi-distributions, we consider\nother approaches: hadronic tensor, auxiliary quark methods, pseudo-PDFs, OPE\nwithout OPE and good lattice cross sections. In closing, we provide prospects\nof the field, with emphasis on the necessary conditions to obtain results with\ncontrolled uncertainties."
    },
    {
        "anchor": "Efficient Modelling of Trivializing Maps for Lattice $\u03c6^4$ Theory\n  Using Normalizing Flows: A First Look at Scalability: General-purpose Markov Chain Monte Carlo sampling algorithms suffer from a\ndramatic reduction in efficiency as the system being studied is driven towards\na critical point. Recently, a series of seminal studies suggested that\nnormalizing flows - a class of deep generative models - can form the basis of a\nsampling strategy that does not suffer from this 'critical slowing down'. The\ncentral idea is to use machine learning techniques to build (approximate)\ntrivializing maps, i.e. field transformations that map the theory of interest\ninto a 'simpler' theory in which the degrees of freedom decouple, and where the\nstatistical weight in the path integral is given by a distribution from which\nsampling is easy. No separate process is required to generate training data for\nsuch models, and convergence to the desired distribution is guaranteed through\na reweighting procedure such as a Metropolis test. In a proof-of-principle\ndemonstration on two-dimensional $\\phi^4$ theory, Albergo et al.\n(arXiv:1904.12072) modelled the trivializing map as a sequence of pointwise\naffine transformations. We pick up this thread, with the aim of quantifying how\nwell we can expect this approach to scale as we increase the number of degrees\nof freedom in the system. We make several modifications to the original design\nthat allow our models learn more efficient representations of trivializing maps\nusing much smaller neural networks, which leads to a large reduction in the\ncomputational cost required to train models of equivalent quality. After making\nthese changes, we find that sampling efficiency is almost entirely dictated by\nhow extensively a model has been trained, while being unresponsive to further\nalterations that increase model flexibility. However, as we move towards the\ncontinuum limit the training costs scale extremely quickly, which urgently\nrequires further work to fully understand and mitigate.",
        "positive": "Towards a precise determination of the topological susceptibility in the\n  SU(3) Yang-Mills theory: An ongoing effort to compute the topological susceptibility for the SU(3)\nYang-Mills theory in the continuum limit with a precison of about 2% is\nreported. The susceptibility is computed by using the definition of the charge\nsuggested by Neuberger fermions for two values of the negative mass parameter\ns. Finite volume and discretization effects are estimated to meet this level of\nprecision. The large statistics required has been obtained by using PCs of the\nINFN-GRID. Simulations with larger lattice volumes are necessary in order to\nbetter understanding the continuum limit at small lattice spacing values."
    },
    {
        "anchor": "The Index Theorem and Universality Properties of the Low-lying\n  Eigenvalues of Improved Staggered Quarks: We study various improved staggered quark Dirac operators on quenched gluon\nbackgrounds in lattice QCD generated using a Symanzik-improved gluon action. We\nfind a clear separation of the spectrum into would-be zero modes and others.\nThe number of would-be zero modes depends on the topological charge as expected\nfrom the Index Theorem, and their chirality expectation value is large\n(approximately 0.7). The remaining modes have low chirality and show clear\nsigns of clustering into quartets and approaching the random matrix theory\npredictions for all topological charge sectors. We conclude that improvement of\nthe fermionic and gauge actions moves the staggered quarks closer to the\ncontinuum limit where they respond correctly to QCD topology.",
        "positive": "Domain wall fermions with Majorana couplings: We examine the lattice boundary formulation of chiral fermions with either an\nexplicit Majorana mass or a Higgs-Majorana coupling introduced on one of the\nboundaries. We demonstrate that the low-lying spectrum of the models with an\nexplicit Majorana mass of the order of an inverse lattice spacing is chiral at\ntree level. Within a mean-field approximation we show that the systems with a\nstrong Higgs-Majorana coupling have a symmetric phase, in which a Majorana mass\nof the order of an inverse lattice spacing is generated without spontaneous\nbreaking of the gauge symmetry. We argue, however, that the models within such\na phase have a chiral spectrum only in terms of the fermions that are singlets\nunder the gauge group. The application of such systems to nonperturbative\nformulations of supersymmetric and chiral gauge theories is briefly discussed."
    },
    {
        "anchor": "QCD thermodynamics with 2+1 flavors at nonzero chemical potential: We present results for the QCD equation of state, quark densities and\nsusceptibilities at nonzero chemical potential, using 2+1 flavor asqtad\nensembles with $N_t=4$. The ensembles lie on a trajectory of constant physics\nfor which $m_{ud}\\approx0.1m_s$. The calculation is performed using the Taylor\nexpansion method with terms up to sixth order in $\\mu/T$.",
        "positive": "Universal Properties of Chiral Simmetry Breaking: We discuss chiral symmetry breaking critical points from the perspective of\nPCAC, correlation length scaling and the chiral equation of state. A scaling\ntheory for the ratio $R_\\pi$ of the pion to sigma masses is presented. The\nGoldstone character of the pion and properties of the longitudinal and\ntransverse chiral susceptibilities determine the ratio $R_\\pi$ which can be\nused to locate critical points and measure critical indices such as $\\delta$.\nWe show how PCAC and correlation length scaling determine the pion mass'\ndependence on the chiral condensate and lead to a practical method to measure\nthe anomalous dimension $\\eta$. These tools are proving useful in studies of\nthe chiral transition in lattice QED and the quark-gluon plasma transition in\nlattice QCD."
    },
    {
        "anchor": "Softening of First-Order Phase Transition on Quenched Random Gravity\n  Graphs: We perform extensive Monte Carlo simulations of the 10-state Potts model on\nquenched two-dimensional $\\Phi^3$ gravity graphs to study the effect of\nquenched coordination number randomness on the nature of the phase transition,\nwhich is strongly first order on regular lattices. The numerical data provides\nstrong evidence that, due to the quenched randomness, the discontinuous\nfirst-order phase transition of the pure model is softened to a continuous\ntransition, representing presumably a new universality class. This result is in\nstriking contrast to a recent Monte Carlo study of the 8-state Potts model on\ntwo-dimensional Poissonian random lattices of Voronoi/Delaunay type, where the\nphase transition clearly stayed of first order, but is in qualitative agreement\nwith results for quenched bond randomness on regular lattices. A precedent for\nsuch softening with connectivity disorder is known: in the 10-state Potts model\non annealed Phi3 gravity graphs a continuous transition is also observed.",
        "positive": "Contribution of the QCD $\u0398$-term to nucleon electric dipole moment: We present a calculation of the contribution of the $\\Theta$-term to the\nneutron and proton electric dipole moments using seven 2+1+1-flavor HISQ\nensembles. We also estimate the topological susceptibility for the 2+1+1 theory\nto be $\\chi_Q = (66(9)(4) \\rm MeV)^4$ in the continuum limit at $M_\\pi = 135$\nMeV. The calculation of the nucleon three-point function is done using\nWilson-clover valence quarks. The CP-violating form factor $F_3$ is calculated\nby expanding in small $\\Theta$. We show that lattice artifacts introduce a term\nproportional to $a$ that does not vanish in the chiral limit, and we include\nthis in our chiral-continuum fits. A chiral perturbation theory analysis shows\nthat the $N(0) \\pi(0)$ state should provide the leading excited state\ncontribution, and we study the effect of such a state. Detailed analysis of the\ncontributions to the neutron and proton electric dipole moment using two\nstrategies for removing excited state contamination are presented. Using the\nexcited state spectrum from fits to the two-point function, we find\n$d_n^\\Theta$ is small, $|d_n^\\Theta| \\lesssim 0.01 \\overline \\Theta e$ fm,\nwhereas for the proton we get $|d_p^\\Theta| \\sim 0.02 \\overline \\Theta e$ fm.\nOn the other hand, if the dominant excited-state contribution is from the $N\n\\pi$ state, then $|d_n^\\Theta|$ could be as large as $0.05 \\overline \\Theta e$\nfm and $|d_p^\\Theta| \\sim 0.07 \\overline \\Theta e$ fm. Our overall conclusion\nis that present lattice QCD calculations do not provide a reliable estimate of\nthe contribution of the $\\Theta$-term to the nucleon electric dipole moments,\nand a factor of ten higher statistics data are needed to get better control\nover the systematics and possibly a $3\\sigma$ result."
    },
    {
        "anchor": "The large-N phase transition of lattice SU(N) gauge theories: We investigate the large-N phase transition of lattice SU(N) gauge theories\nin the Wilson formulation, by performing a Monte Carlo simulation of the\ntwisted Eguchi-Kawai model. A variant of the multicanonical algorithm allows a\ndetailed exploration of the phase transition and a precise determination of the\ntransition temperature.",
        "positive": "QCD with light Wilson quarks on fine lattices (I): first experiences and\n  physics results: Recent conceptual, algorithmic and technical advances allow numerical\nsimulations of lattice QCD with Wilson quarks to be performed at significantly\nsmaller quark masses than was possible before. Here we report on simulations of\ntwo-flavour QCD at sea-quark masses from slightly above to approximately 1/4 of\nthe strange-quark mass, on lattices with up to 64x32^3 points and spacings from\n0.05 to 0.08 fm. Physical sea-quark effects are clearly seen on these lattices,\nwhile the lattice effects appear to be quite small, even without O(a)\nimprovement. A striking result is that the dependence of the pion mass on the\nsea-quark mass is accurately described by leading-order chiral perturbation\ntheory up to meson masses of about 500 MeV."
    },
    {
        "anchor": "Dynamical Fermions in Hamiltonian Lattice Gauge Theory: We describe a first attempt to understand dynamical fermions within a\nHamiltonian framework. As a testing ground we study compact QED3 which shares\nsome important features of QCD4 such as confinement, glueballs, mesons, and\nchiral symmetry breaking. We discuss the methods used and show data for the\nchiral condensate.",
        "positive": "Latent heat at the first order phase transition point of SU(3) gauge\n  theory: We calculate the energy gap (latent heat) and pressure gap between the hot\nand cold phases of the SU(3) gauge theory at the first order deconfining phase\ntransition point. We perform simulations around the phase transition point with\nthe lattice size in the temporal direction Nt=6, 8 and 12 and extrapolate the\nresults to the continuum limit. We also investigate the spatial volume\ndependence. The energy density and pressure are evaluated by the derivative\nmethod with non-perturabative anisotropy coefficients. We adopt a multi-point\nreweighting method to determine the anisotropy coefficients. We confirm that\nthe anisotropy coefficients approach the perturbative values as Nt increases.\nWe find that the pressure gap vanishes at all values of Nt when the\nnon-perturbative anisotropy coefficients are used. The spatial volume\ndependence in the latent heat is found to be small on large lattices.\nPerforming extrapolation to the continuum limit, we obtain $ \\Delta\n\\epsilon/T^4 = 0.75 \\pm 0.17 $ and $ \\Delta (\\epsilon -3 p)/T^4 = 0.623 \\pm\n0.056.$"
    },
    {
        "anchor": "A Study of Finite Temperature Gauge Theory in (2+1) Dimensions: We determine the critical couplings and the critical exponents of the finite\ntemperature transition in SU(2) and SU(3) pure gauge theory in (2+1)\ndimensions. We also measure Wilson loops at $T=0$ on a wide range of $\\beta$\nvalues using APE smearing to improve the signal. We extract the string tension\n$\\sigma$ from a fit to large distances, including a string fluctuation term.\nWith these two entities we calculate $T_c/\\sqrt{\\sigma}$.",
        "positive": "Can we study Quark Matter in the Quenched Approximation?: We study a quenched SU(2) lattice gauge theory in which, in an attempt to\ndistinguish between timelike and spacelike gauge fields, the gauge ensemble\n{U_mu} is generated from a 3 dimensional gauge-Higgs model, the timelike link\nvariables being \"reconstructed\" from the Higgs fields. The resulting ensemble\nis used to study quenched quark propagation with non-zero chemical potential\nmu; in particular, the quark density, chiral and superfluid condensates, meson,\nbaryon and gauge-fixed quark propagators are all studied as functions of mu.\nWhile it proves possible to alter the strength of the inter-quark interaction\nby changing the parameters of the dimensionally reduced model, there is no\nevidence for any region of parameter space where quarks exhibit deconfined\nbehaviour or thermodynamic observables scale as if there were a Fermi surface."
    },
    {
        "anchor": "High-Temperature series for the $RP^{n-1}$ lattice spin model\n  (generalized Maier-Saupe model of nematic liquid crystals) in two space\n  dimensions and with general spin dimensionality n: High temperature series expansions of the spin-spin correlation functions of\nthe RP^{n-1} spin model on the square lattice are computed through order\nbeta^{8} for general spin dimensionality n. Tables are reported for the\nexpansion coefficients of the energy per site, the susceptibility and the\nsecond correlation moment.",
        "positive": "Excited and exotic charmonium, $D_s$ and $D$ meson spectra for two light\n  quark masses from lattice QCD: We present highly-excited charmonium, $D_s$ and $D$ meson spectra from\ndynamical lattice QCD calculations with light quarks corresponding to $M_{\\pi}\n\\sim 240$ MeV and compare these to previous results with $M_{\\pi} \\sim 400$\nMeV. Utilising the distillation framework, large bases of carefully constructed\ninterpolating operators and a variational procedure, we extract and reliably\nidentify the continuum spin of an extensive set of excited mesons. These\ninclude states with exotic quantum numbers which, along with a number with\nnon-exotic quantum numbers, we identify as having excited gluonic degrees of\nfreedom and interpret as hybrid mesons. Comparing the spectra at the two\ndifferent $M_\\pi$, we find only a mild light-quark mass dependence and no\nchange in the overall pattern of states."
    },
    {
        "anchor": "The Schroedinger functional coupling in quenched QCD at low energies: Existing non-perturbative computations of the running coupling of quenched\nQCD in the Schroedinger functional scheme are extended to scales mu lying much\ndeeper in the low-energy regime. We are able to reach 1/mu ~ 0.9 fm, where a\nsignificant deviation from its perturbative evolution is observed.",
        "positive": "Progress and prospects of lattice supersymmetry: Supersymmetry plays prominent roles in the study of quantum field theory and\nin many proposals for potential new physics beyond the standard model, while\nlattice field theory provides a non-perturbative regularization suitable for\nstrongly interacting systems. Lattice investigations of supersymmetric field\ntheories are currently making significant progress, though many challenges\nremain to be overcome. In this brief overview I discuss particularly notable\nprogress in three areas: supersymmetric Yang--Mills (SYM) theories in fewer\nthan four dimensions, as well as both minimal N=1 SYM and maximal N=4 SYM in\nfour dimensions. I also highlight super-QCD and sign problems as prominent\nchallenges that will be important to address in future work."
    },
    {
        "anchor": "Stout-link smearing in lattice fermion actions: The properties of the momentum space quark propagator in Landau gauge are\nstudied for the overlap quark action in quenched lattice QCD. Numerical\ncalculations are performed over four ensembles of gauge configurations, where\nthree are smeared using either 1, 3, or 6 sweeps of stout-link smearing. We\ncalculate the non-perturbative wave function renormalization function $Z(p)$\nand the non-perturbative mass function $M(p)$ for a variety of bare quark\nmasses. We find that the wave-function renormalization function is slightly\nsensitive to the number of stout-link smearing sweeps. For the mass function we\nfind the effect of the stout-link smearing algorithm to be small for moderate\nto light bare quark masses. For a heavy bare quark mass we find a strong\ndependence on the number of smearing sweeps.",
        "positive": "Finite-volume corrections to the leading-order hadronic contribution to\n  $g_\u03bc-2$: We present preliminary results of a 2+1-flavor study of finite-volume effects\nin the lattice QCD computation of the leading-order hadronic contribution to\nthe muon anomalous magnetic moment. We also present methods for obtaining\ndirectly the invariant hadronic polarization function, $\\Pi(Q^2)$, and the\nAdler function at all discrete lattice values of $Q^2$, including $Q^2=0$.\nResults are obtained with HEX-smeared clover fermions."
    },
    {
        "anchor": "Quenched $SU(3)$ hadron spectroscopy using improved fermionic and gauge\n  actions: We present results of quenched $SU(3)$ hadron spectroscopy using $\\order(a)$\nimproved Wilson fermions. The configurations were generated using an\n$\\order(a^2)$ improved 6-link $SU(3)$ pure gauge action at $\\beta$'s\ncorresponding to lattice spacings of $0.43$, $0.25$, $0.20$, $0.18$, and $0.15$\nfm. We find evidence that fermionic scaling violations are consistent with\n$\\order(a^2)$ errors.",
        "positive": "Scaling properties of Wilson loops pierced by P-vortices: P-vortices, in an SU(N) lattice gauge theory, are excitations on the\ncenter-projected Z(N) lattice. We study the ratio of expectation values of\nSU(2) Wilson loops, on the unprojected lattice, linked to a single P-vortex, to\nthat of Wilson loops which are not linked to any P-vortices. When these ratios\nare plotted versus loop area in physical units, for a range of lattice\ncouplings, it is found that the points fall approximately on a single curve,\nconsistent with scaling. We also find that the ratios are rather insensitive to\nthe point where the minimal area of the loop is pierced by the P-vortex."
    },
    {
        "anchor": "Strange quark mass and Lambda parameter by the ALPHA collaboration: We determine f_K for lattice QCD in the two flavor approximation with\nnon-perturbatively improved Wilson fermions. The result is used to set the\nscale for dimensionful quantities in CLS/ALPHA simulations. To control its\ndependence on the light quark mass, two different strategies for the chiral\nextrapolation are applied. Combining f_K and the bare strange quark mass with\nnon-perturbative renormalization factors and step scaling functions computed in\nthe Schroedinger Functional, we determine the RGI strange quark mass and the\nLambda parameter in units of f_K.",
        "positive": "Phases of many flavors QCD : Lattice results: This note is based on our recent results on QCD with varying number of\nflavors of fundamental fermions. Topics include unusual, strong dynamics in the\npreconformal, confining phase, the physics of the conformal window and the role\nof ab-initio lattice simulations in establishing our current knowledge of the\nphases of many flavor QCD"
    },
    {
        "anchor": "Applications of the Feynman-Hellmann theorem in hadron structure: The Feynman-Hellmann (FH) relation offers an alternative way of accessing\nhadronic matrix elements through artificial modifications to the QCD\nLagrangian. In particular, a FH-motivated method provides a new approach to\ncalculations of disconnected contributions to matrix elements and high-momentum\nnucleon and pion form factors. Here we present results for the total nucleon\naxial charge, including a statistically significant non-negative total\ndisconnected quark contribution of around $-5\\%$ at an unphysically heavy pion\nmass. Extending the FH relation to finite-momentum transfers, we also present\ncalculations of the pion and nucleon electromagnetic form factors up to\nmomentum transfers of around 7-8 GeV$^2$. Results for the nucleon are not able\nto confirm the existence of a sign change for the ratio $\\frac{G_E}{G_M}$, but\nsuggest that future calculations at lighter pion masses will provide\nfascinating insight into this behaviour at large momentum transfers.",
        "positive": "Strong coupling expansion for scattering phases in hamiltonian lattice\n  field theories - II. SU(2) gauge theory in (2+1) dimensions: A recently proposed method for a strong coupling analysis of scattering\nphenomena in hamiltonian lattice field theories is applied to the $\\SU2$\nYang-Mills model in $(2+1)$ dimensions. The calculation is performed up to\nsecond order in the hopping parameter. All relevant quantities that\ncharacterize the collision between the lightest glueballs in the elastic region\n-- cross section, phase shifts, resonance parameters -- are determined."
    },
    {
        "anchor": "Crossing the c=1 barrier in 2d Lorentzian quantum gravity: In an extension of earlier work we investigate the behaviour of\ntwo-dimensional Lorentzian quantum gravity under coupling to a conformal field\ntheory with c>1. This is done by analyzing numerically a system of eight Ising\nmodels (corresponding to c=4) coupled to dynamically triangulated Lorentzian\ngeometries. It is known that a single Ising model couples weakly to Lorentzian\nquantum gravity, in the sense that the Hausdorff dimension of the ensemble of\ntwo-geometries is two (as in pure Lorentzian quantum gravity) and the matter\nbehaviour is governed by the Onsager exponents. By increasing the amount of\nmatter to 8 Ising models, we find that the geometry of the combined system has\nundergone a phase transition. The new phase is characterized by an anomalous\nscaling of spatial length relative to proper time at large distances, and as a\nconsequence the Hausdorff dimension is now three. In spite of this qualitative\nchange in the geometric sector, and a very strong interaction between matter\nand geometry, the critical exponents of the Ising model retain their Onsager\nvalues. This provides evidence for the conjecture that the KPZ values of the\ncritical exponents in 2d Euclidean quantum gravity are entirely due to the\npresence of baby universes. Lastly, we summarize the lessons learned so far\nfrom 2d Lorentzian quantum gravity.",
        "positive": "Charm baryons at finite temperature on anisotropic lattices: Singly, doubly and triply charmed baryons are investigated at multiple\ntemperatures using the anisotropic FASTSUM 'Generation 2L' ensembles. We\ndiscuss the temperature dependence of these baryons' spectra in both parity\nchannels with a focus on the confining phase. To further qualify the behaviour\nof these states around the pseudocritical temperature, we investigate the\neffect of chiral symmetry restoration for light quarks. We find that an\nestimate of the pseudocritical temperature can still be found from positive and\nnegative-parity charmed baryon correlators, even when parity doubling itself is\nnot very evident (as expected)."
    },
    {
        "anchor": "On the Schroedinger functional in QCD: In a series of publications [\\ref{LNWW},\\ref{Schroedinger}], L\\\"uscher et al.\nhave demonstrated the usefulness of the Schr\\\"odinger functional in pure SU(2)\nand SU(3) gauge theory. In this paper, it is shown how their formalism can be\nextended to include fermions. In the framework of Wilson's lattice QCD, we\ndefine the Schr\\\"odinger functional by making use of the transfer matrix\nformalism. Boundary conditions for the fermions arise naturally. We then take\nthe naive continuum limit of the action and show that no lattice peculiarities\nare left over. The corresponding free Dirac operator has a unique self-adjoint\nextension with purely discrete spectrum and no zero modes.",
        "positive": "Status of ETMC simulations with Nf=2+1+1 twisted mass fermions: We present the status of runs performed in the twisted mass formalism with\n$N_{\\rm f}=2+1+1$ flavours of dynamical fermions: a degenerate light doublet\nand a mass split heavy doublet. The procedure for tuning to maximal twist will\nbe described as well as the current status of the runs using both thin and\nstout links. Preliminary results for a few observables obtained on ensembles at\nmaximal twist will be given. Finally, a reweighting procedure to tune to\nmaximal twist will be described."
    },
    {
        "anchor": "An Euclidean representation of Majorana spins: An Euclidean representation of bosonized Majorana fermions, prior to imposing\nconstraints, is derived in three space-time dimensons. The difference with the\nstandard three dimensional Ising system is epmhasized. The mild sign problem,\ndoes not preclude Monte Carlo simulations in intermediate volumes. Implementing\nconstraints is briefly outlined.",
        "positive": "Gribov Copies and Smeared Correlation Functions in Lattice QCD: We study the influence of Gribov copies in the Coulomb gauge on the smeared\nhadronic correlation functions that are involved in the determination of the B\nmeson decay constant. We find that the residual gauge freedom associated to\nGribov copies induces observable noise effects, though at the level of\nnumerical accuracy of our simulation these effects are not relevant to the\nfinal determination of f_B. Our results indicate that such effects may become\nimportant on bigger lattices."
    },
    {
        "anchor": "The infrared behaviour of the gluon propagator from lattice QCD: The gluon propagator in the Landau gauge is calculated in quenched QCD on a\nlarge lattice (32^3x64) at beta=6.0. In order to assess finite volume and\nfinite lattice spacing artefacts, we also calculate the propagator on a smaller\nvolume for two different values of the lattice spacing. New structure seen in\nthe infrared region survives conservative cuts to the lattice data, and serves\nto exclude a number of models that have appeared in the literature.",
        "positive": "Simulations with Complex Measures: Towards a solution to the sign problem in the simulations of systems having\nindefinite or complex-valued measures, we propose a new approach which yields\nstatistical errors smaller than the crude Monte Carlo using absolute values of\nthe original measures. The 1D complex-coupling Ising model is employed as an\nillustration."
    },
    {
        "anchor": "Radial Excited States for Heavy Quark Systems in NRQCD: Following the Non-Relativistic QCD approach we use a gauge invariant smearing\nmethod with factorization to measure the excitation energies for a heavy\n$Q\\bar{Q}$ system on a $24^3\\times 48$ lattice at $\\beta=6.2$. The results come\nfrom averaging over an ensemble of 60 QCD configurations. In order to enhance\nthe signal from each configuration we use wall sources for quark propagators.\nThe quark Hamiltonian contains only the simplest non-relativistic kinetic\nenergy term. The results are listed for a range of bare quark masses. The mass\nsplittings are insensitive to this variable though there are a slight trends\nwith increasing quark mass. For an appropriate choice of UV cut-off\n($a^{-1}=3.2$Gev) the mass spectrum compares reasonably well with the\nexperimental values for the spin-averaged energy gaps of the $\\Upsilon$ system.\nWe also present results for the $DE$ and $DT$ waves for the lowest bare quark\nmass. The results are consistent with degeneracy between the two types of $D$\nwave. This encourages the idea that even with our simple quark Hamiltonian the\ndeparture from rotational invariance is not great.",
        "positive": "Compactified N=1 supersymmetric Yang-Mills theory on the lattice:\n  Continuity and the disappearance of the deconfinement transition: Fermion boundary conditions play a relevant role in revealing the confinement\nmechanism of N=1 supersymmetric Yang-Mills theory with one compactified\nspace-time dimension. A deconfinement phase transition occurs for a\nsufficiently small compactification radius, equivalent to a high temperature in\nthe thermal theory where antiperiodic fermion boundary conditions are applied.\nPeriodic fermion boundary conditions, on the other hand, are related to the\nWitten index and confinement is expected to persist independently of the length\nof the compactified dimension. We study this aspect with lattice Monte Carlo\nsimulations for different values of the fermion mass parameter that breaks\nsupersymmetry softly. We find a deconfined region that shrinks when the fermion\nmass is lowered. Deconfinement takes place between two confined regions at\nlarge and small compactification radii, that would correspond to low and high\ntemperatures in the thermal theory. At the smallest fermion masses we find no\nindication of a deconfinement transition. These results are a first signal for\nthe predicted continuity in the compactification of supersymmetric Yang-Mills\ntheory."
    },
    {
        "anchor": "Vortex waistlines and vortex gas: We investigate the manner in which a linear potential arises from\nfluctuations due to vortices linked with the Wilson loop. In particular, the\ncustomary naive picture is critically reexamined.",
        "positive": "Setting the scale for the CLS $2 + 1$ flavor ensembles: We present measurements of a combination of the decay constants of the light\npseudoscalar mesons and the gradient flow scale $t_0$, which allow to set the\nscale of the lattices generated by CLS with $2 + 1$ flavors of\nnon-perturbatively improved Wilson fermions. Mistunings of the quark masses are\ncorrected for by measuring the derivatives of observables with respect to the\nbare quark masses."
    },
    {
        "anchor": "Lattice QCD simulation of the Berry curvature: The Berry curvature is a fundamental concept describing topological order of\nquantum systems. While it can be analytically tractable in non-interacting\nsystems, numerical simulations are necessary in interacting systems. We present\na formulation to calculate the Berry curvature in lattice QCD.",
        "positive": "First results in QCD with 2+1 light flavors using the fixed-point action: This is a progress report on 2+1 flavor simulation with the FP action on a\nlattice with spatial size L=1.2fm. Since m_{ud} is quite small in our\nsimulation we are in the delta regime for the two light flavors where the low\nlying excitations are described by a quantum mechanical rotator. From here we\nextract the low energy constant F. We also measure the AWI mass and present\nresults on numerical issues like low-mode averaging and autocorrelation times."
    },
    {
        "anchor": "RI/(S)MOM renormalizations of overlap quark bilinears with different\n  levels of hypercubic smearing: On configurations with 2+1-flavor dynamical domain-wall fermions, we\ncalculate the RI/(S)MOM renormalization constants (RC) of overlap quark\nbilinears. Hypercubic (HYP) smearing is used to construct the overlap Dirac\noperator. We investigate the possible effects of the smearing on discretization\nerrors in the RCs by varying the level of smearing from 0 to 1 and 2. The\nlattice is of size $32^3\\times64$ and with lattice spacing $1/a=2.383(9)$ GeV.\nThe RCs in the $\\overline{\\rm MS}$ scheme at 2 GeV are given at the end, with\nthe uncertainty of $Z_T$ reaching $\\le1$% for the tensor current. Results of\nthe renormalized quark masses and hadron matrix elements show that the\nrenormalization procedure suppresses the $\\sim$ 30% difference of the bare\nquantities with or without HYP smearing into the 3%-5% level.",
        "positive": "Hyperons in thermal QCD: A lattice view: The hadron resonance gas (HRG) is a widely used description of matter under\nextreme conditions, e.g. in the context of heavy-ion phenomenology. Commonly\nused implementations of the HRG employ vacuum hadron masses throughout the\nhadronic phase and hence do not include possible in-medium effects. Here we\ninvestigate this issue, using nonperturbative lattice simulations employing the\nFASTSUM anisotropic Nf=2+1 ensembles. We study the fate of octet and decuplet\nbaryons as the temperature increases, focussing in particular on the positive-\nand negative-parity groundstates. While the positive-parity groundstate masses\nare indeed seen to be temperature independent, within the error, a strong\ntemperature dependence is observed in the negative-parity channels. We give a\nsimple parametrisation of this and formulate an in-medium HRG, which is\nparticularly effective for hyperons. Parity doubling is seen to emerge in the\ndeconfined phase at the level of correlators, with a noticeable effect of the\nheavier s quark. Channel dependence of this transition is analysed."
    },
    {
        "anchor": "A strategy to study the role of the charm quark in explaining the\n  Delta{I}=1/2 rule: We present a strategy designed to separate several possible origins of the\nwell-known enhancement of the Delta{I}=1/2 amplitude in non-leptonic kaon\ndecays. In particular, we seek to disentangle the contribution of physics at\nthe typical QCD scale (soft-gluon exchange) from the effects at the scale of\nthe charm quark mass. This is achieved by considering QCD with an unphysically\nlight charm quark, so that the theory possesses an approximate SU(4)_L x\nSU(4)_R chiral symmetry. By computing the relevant operator matrix elements and\nmonitoring their values as the charm quark mass departs from the\nSU(4)-symmetric situation, the role of the charm quark can be assessed. We\nstudy the influence of the charm quark mass in Chiral Perturbation Theory.\nFirst results from lattice simulations in the SU(4)-symmetric limit are also\ndiscussed.",
        "positive": "Lattice baryons in the 1/N expansion: Results are presented for hadron spectroscopy with gauge groups SU(N) with\nN=3, 5, 7. Calculations use the quenched approximation. Lattice spacings are\nmatched using the static potential. Meson spectra show independence on N and\nvacuum-to-hadron matrix elements scale as the square root of N. The baryon\nspectrum shows the excitation levels of a rigid rotor."
    },
    {
        "anchor": "Novel quark smearing for hadrons with high momenta in lattice QCD: Hadrons in lattice QCD are usually created employing smeared interpolators.\nWe introduce a new quark smearing that allows us to maintain small statistical\nerrors and good overlaps of hadronic wavefunctions with the respective ground\nstates, also at high spatial momenta. The method is successfully tested for the\npion and the nucleon at a pion mass $m_{\\pi}\\approx 295$ MeV and momenta as\nhigh as 2.8 GeV. We compare the results obtained to dispersion relations and\nsuggest further optimizations.",
        "positive": "QCD Critical Point and Complex Chemical Potential Singularities: The thermodynamic singularities of QCD in the plane of complex baryo-chemical\npotential mu are studied. Predictions are made using scaling and universality\narguments in the vicinity of the massless quark limit. The results are\nillustrated by a calculation of complex mu singularities in a random matrix\nmodel at finite temperature. Implications for lattice QCD simulations aimed at\nlocating the QCD critical point are discussed."
    },
    {
        "anchor": "Tuning the Tadpole Improved Clover Wilson Action on Coarse Anisotropic\n  Lattices: Wilson quark action, with tadpole improved clover term added, is studied on\ncoarse anisotropic lattices. The bare velocity of light parameter in this\naction is determined non-perturbatively using the pseudo-scalar and vector\nmeson dispersion relations for various values of the gauge coupling $\\beta$ and\nbare quark mass parameter $\\kappa$.",
        "positive": "The isentropic equation of state of 2-flavor QCD: Using Taylor expansions of the pressure obtained previously in studies of\n2-flavor QCD at non-zero chemical potential we calculate expansion coefficients\nfor the energy and entropy densities up to ${\\cal O}(\\mu_q^6)$ in the quark\nchemical potential. We use these series in $\\mu_q/T$ to determine lines of\nconstant entropy per baryon number ($S/N_B$) that characterize the expansion of\ndense matter created in heavy ion collisions. In the high temperature regime\nthese lines are found to be well approximated by lines of constant $\\mu_q/T$.\nIn the low temperature phase, however, the quark chemical potential is found to\nincrease with decreasing temperature. This is in accordance with resonance gas\nmodel calculations. Along the lines of constant $S/N_B$ we calculate the energy\ndensity and pressure. Within the accuracy of our present analysis we find that\nthe ratio $p/\\epsilon$ for $T>T_0$ as well as the softest point of the equation\nof state, $(p/\\epsilon)_{min}\\simeq 0.075$, show no significant dependence on\n$S/N_B$."
    },
    {
        "anchor": "Effects of Topology in the Dirac Spectrum of Staggered Fermions: We compare the lower edge spectral fluctuations of the staggered lattice\nDirac operator for the Schwinger model with the predictions of chiral Random\nMatrix Theory (chRMT). We verify their range of applicability, checking in\nparticular the role of non-trivial topological sectors and the flavor symmetry\nof the staggered fermions for finite lattice spacing. Approaching the continuum\nlimit we indeed find clear signals for topological modes in the eigenvalue\nspectrum. These findings indicate problems in the verification of the chRMT\npredictions.",
        "positive": "Longitudinal and transverse meson correlators in the deconfined phase\n  from the lattice: It has long been known that QCD undergoes a deconfining phase transition at\nhigh temperature. One of the consequent features of this new, quark-gluon phase\nis that hadrons become unbounded. In this talk meson correlation functions at\nnon-zero momentum are studied in the deconfined phase using the Maximum Entropy\nMethod."
    },
    {
        "anchor": "Chiral behavior of light meson form factors in 2+1 flavor QCD with exact\n  chiral symmetry: We present a study of chiral behavior of light meson form factors in QCD with\nthree flavors of overlap quarks. Gauge ensembles are generated at single\nlattice spacing 0.12 fm with pion masses down to 300 MeV. The pion and kaon\nelectromagnetic form factors and the kaon semileptonic form factors are\nprecisely calculated using the all-to-all quark propagator. We discuss their\nchiral behavior using the next-to-next-to-leading order chiral perturbation\ntheory.",
        "positive": "Three topics of monopole dynamics in abelian projected QCD: Three topics about monopole dynamics after abelian projection are reported.\nThe first is the new and detailed analyses of $SU(2)$ monopole action obtained\nafter the block-spin transformation on the dual lattice. The $b=na(\\beta)$\ndependence for all couplings are well fitted with a universal curve. The\ndistance dependence of the couplings is well reproduced by a massive propagator\nwith the mass $m=0.8$ in unit of $b$. The second is the $SU(3)$ monopole action\nrecently obtained. The third is new interesting gauges showing abelian and\nmonopole dominances as in the maximally abelian gauge."
    },
    {
        "anchor": "QCD simulations at small chemical potential: Within the reweighting approach, one has the freedom to choose the Monte\nCarlo action so that it provides a good overlap with the finite-\\mu measure but\nremains simple to simulate. We explore several choices of action in the regime\nof small \\mu. Simulating with a finite isospin chemical potential \\mu_I=\\mu\ngives a better overlap than the standard choice \\mu=0, with no computational\noverhead.",
        "positive": "Monte Carlo evaluation of the continuum limit of the two-point function\n  of the Euclidean free real scalar field subject to affine quantization: We study canonical and affine versions of the quantized covariant Euclidean\nfree real scalar field-theory on four dimensional lattices through the Monte\nCarlo method. We calculate the two-point function at small values of the bare\ncoupling constant and near the continuum limit at finite volume. Our\ninvestigation shows that affine quantization is able to give meaningful results\nfor the two-point function for which is not available an exact analytic result\nand therefore numerical methods are necessary."
    },
    {
        "anchor": "Lattice study of electromagnetic conductivity of quark-gluon plasma in\n  external magnetic field: We study the electromagnetic (e.m.) conductivity of QGP in a magnetic\nbackground by lattice simulations with $N_f = 2+1$ dynamical rooted staggered\nfermions at the physical point. We study the correlation functions of the\ne.m.~currents at $T=200,\\,250$\\,MeV and use the Tikhonov approach to extract\nthe conductivity. This is found to rise with the magnetic field in the\ndirection parallel to it and to decrease in the transverse direction, giving\nevidence for both the Chiral Magnetic Effect and the magnetoresistance\nphenomenon in QGP. We also estimate the chiral charge relaxation time in QGP.",
        "positive": "QCD Phase Diagram with Imaginary Chemical Potential: We report our recent results on the QCD phase diagram obtained from the\nlattice QCD simulation. The location of the phase boundary between hadronic and\nQGP phases in the two-flavor QCD phase diagram is investigated. The imaginary\nchemical potential approach is employed, which is based on Monte Carlo\nsimulations of the QCD with imaginary chemical potential and analytic\ncontinuation to the real chemical potential region."
    },
    {
        "anchor": "Comparison of algorithms for solving the sign problem in the O(3) model\n  in 1+1 dimensions at finite chemical potential: We study three possible ways to circumvent the sign problem in the O(3)\nnonlinear sigma model in 1+1 dimensions. We compare the results of the worm\nalgorithm to complex Langevin and multiparameter reweighting. Using the worm\nalgorithm, the thermodynamics of the model is investigated, and continuum\nresults are shown for the pressure at different $\\mu/T$ values in the range\n$0-4$. By performing $T=0$ simulations using the worm algorithm the Silver\nBlaze phenomenon is reproduced. Regarding the complex Langevin, we test various\nimplementations of discretizing the complex Langevin equation. We found that\nthe exponentialized Euler discretization of the Langevin equation gives wrong\nresults for the action and the density at low $T/m$. By performing continuum\nextrapolation we found that this discrepancy does not disappear and depends\nslightly on temperature. The discretization with spherical coordinates perform\nsimilarly at low $\\mu/T$, but goes wrong also at some higher temperatures at\nhigh $\\mu/T$. However, a third discretization that uses a constraining force to\nachieve the $\\phi^2 = 1$ condition gives correct results for the action, but\nwrong results for the density at low $\\mu/T$.",
        "positive": "Study of the Zc+ channel in lattice QCD: Several charged charmonium-like hadrons called $Z_c$ have been recently\ndiscovered by different experiments. In contrast to conventional hadrons these\ncontain at least two valence quarks and antiquarks ($\\bar{c}c\\bar{d}u$). We\nperform a lattice QCD simulation of the $I^G(J^{PC})=1^+(1^{+-})$ channel\nincluding all relevant two-meson operators under 4.3 GeV: $J/\\psi \\pi$,\n$\\psi_{2S}\\pi$, $\\psi_{1D}\\pi$, $D \\bar{D}^*$, $D^* \\bar{D}^*$, $\\eta_c \\rho$\nas well as additional diquark anti-diquark operators. In our $N_f = 2$\nsimulation with pion mass at 266 MeV we are able to identify all two-meson\nlevels within the energy region of interest. However we find no additional\nlevel identifiable as a candidate for $Z_c$."
    },
    {
        "anchor": "Disconnected contributions to hadronic structure: a new method for\n  stochastic noise reduction: We present a new method for reducing the stochastic noise of all-to-all\npropagators based on stopping the inversion of the propagator before\nconvergence. The method is easy to implement, unbiased and independent of the\nquark action. Applying this method to the calculation of disconnected loops\nneeded for hadronic structure observables we find savings in computer time of\nfactors of 4-12 depending on the operator inserted in the loop. When combined\nwith a hopping parameter expansion technique we obtain combined gains of up to\nfactors of 30 for some operators.",
        "positive": "Quark contribution to the proton spin from 2+1+1-flavor lattice QCD: We present the first chiral-continuum extrapolated up, down and strange quark\nspin contribution to the proton spin using lattice QCD. For the connected\ncontributions, we use eleven ensembles of 2+1+1-flavor of Highly Improved\nStaggered Quarks (HISQ) generated by the MILC Collaboration. They cover four\nlattice spacings $a \\approx \\{0.15,0.12,0.09,0.06\\}$ fm and three pion masses,\n$M_\\pi \\approx \\{315,220,135\\}$ MeV, of which two are at the physical pion\nmass. The disconnected strange calculations are done on seven of these\nensembles, covering the four lattice spacings but only one with the physical\npion mass. The disconnected light quark calculation was done on six ensembles\nat two values of $M_\\pi \\approx \\{315,220\\}$ MeV. High-statistics estimates on\neach ensemble for all three quantities allow us to quantify systematic\nuncertainties and perform a simultaneous chiral-continuum extrapolation in the\nlattice spacing and the light-quark mass. Our final results are $\\Delta u\n\\equiv \\langle 1 \\rangle_{\\Delta u^+} = 0.777(25)(30)$, $\\Delta d \\equiv\n\\langle 1 \\rangle_{\\Delta d^+} = -0.438(18)(30)$, and $\\Delta s \\equiv \\langle\n1 \\rangle_{\\Delta s^+} = -0.053(8)$, adding up to a total quark contribution to\nproton spin of $\\sum_{q=u,d,s} (\\frac{1}{2} \\Delta q) = 0.143(31)(36)$. The\nsecond error is the systematic uncertainty associated with the chiral-continuum\nextrapolation. These results are obtained without model assumptions and are in\ngood agreement with the recent COMPASS analysis $0.13 < \\frac{1}{2} \\Delta\n\\Sigma < 0.18$, and with the $\\Delta q$ obtained from various global analyses\nof polarized beam or target data."
    },
    {
        "anchor": "Coarse graining in effective theories of lattice QCD in 1+1d and 2+1d: In the strong coupling and heavy quark mass regime, lattice QCD dimensionally\nreduces to effective theories of Polyakov loops depending on the parameters of\nthe original Wilson action $\\beta, \\kappa$ and $N_\\tau$. We apply coarse\ngraining techniques to such theories in 1d and 2d, corresponding to lattice QCD\nat finite temperature and non-zero chemical potential in 1+1d and 2+1d,\nrespectively. In 1d the method is applied to the effective theories up to\n$\\mathcal{O}(\\kappa^4)$. Using the transfer matrix, the recursion relations are\nsolved analytically. The thermodynamic limit is taken for some observables.\nAfterwards, continuum extrapolation is performed numerically and results are\ndiscussed. In 2d the coarse graining method is applied in the pure gauge and\nstatic quark limit. Running couplings are obtained and the fixed points of the\ntransformations are discussed. Finally, the critical coupling of the\ndeconfinement transition is determined in both limits. Agreement to about 12%\nwith Monte Carlo results of 2+1d Yang-Mills theory from the literature is\nobserved.",
        "positive": "Pion and kaon form factors using twisted-mass fermions: We present a calculation of the scalar, vector and tensor pion and kaon form\nfactors using one ensemble of two degenerate light, a strange and a charm quark\n($N_f=2+1+1$) of maximally twisted mass fermions with clover improvement. The\nquark masses are chosen so that they produce a pion mass of about 265 MeV, and\na kaon mass of 530 MeV. The lattice spacing of the ensemble is 0.093 fm and the\nlattice has a spatial extent of 3 fm. We use a rest frame, as well as a boosted\nframe to obtain the form factors for a wider and denser set of four-vector\nmomentum transfer squared, $Q^2$. To assess and eliminate excited-states\ncontamination, we analyze several values of the source-sink time separation\nwithin the range of 1.12 - 2.23 fm (1.12 - 1.67 fm) for the rest (boosted)\nframe. The $Q^2$ dependence of the form factors is parametrized using a\nmonopole fit, which leads to the extraction of the corresponding radius, and\nthe tensor anomalous magnetic moment for the tensor form factor. The results\nfor these parametrizations are compared for the pion and kaon to assess the\nlevel of the SU(3) flavor symmetry breaking."
    },
    {
        "anchor": "Heavy-light decay constants using clover valence quarks and three\n  flavors of dynamical improved staggered quarks: Starting in 2001, the MILC Collaboration began a large scale calculation of\nheavy-light meson decay constants using clover valence quarks on ensembles of\nthree flavor configurations. For the coarse configurations, with a=0.12 fm,\neight combinations of dynamical light and strange quarks have been analyzed.\nFor the fine configurations, with a=0.09 fm, three combinations of quark masses\nare studied. Since we last reported on this calculation, statistics have been\nincreased on the fine ensembles, and, more importantly, a preliminary value for\nthe perturbative renormalization of the axial-vector current has become\navailable. Thus, results for f_B, f_{B_s}, f_D and f_{D_s} can, in principle,\nbe calculated in MeV, in addition to decay-constant ratios that were calculated\npreviously.",
        "positive": "Problems with the Quenched Approximation in the Chiral Limit: In the quenched approximation, loops of the light singlet meson (the $\\eta'$)\ngive rise to a type of chiral logarithm absent in full QCD. These logarithms\nare singular in the chiral limit throwing doubt upon the utility of the\nquenched approximation. In previous work, I summed a class of diagrams, leading\nto non-analytic power dependencies such as $\\cond\\propto\nm_q^{-\\delta/(1+\\delta)}$. I suggested, however, that these peculiar results\ncould be redefined away. Here I give an alternative derivation of the results,\nbased on the renormalization group, and argue that they cannot be redefined\naway. I discuss the evidence (or lack thereof) for such effects in numerical\ndata."
    },
    {
        "anchor": "On the Extraction of the Strong Coupling from Hadronic Tau Decay: The finite energy sum rule extraction of the strong coupling {\\alpha}_s from\nhadronic {\\tau} decay data provides one of its most precise experimental\ndeterminations. As precision improves, small non-perturbative effects become\nincreasingly relevant to both the central value and error. Here we present a\nnew framework for this extraction employing a physically motivated model to\naccommodate violations of quark-hadron duality and enforcing a consistent\ntreatment of higher-dimension operator product expansion contributions. Using\n1998 OPAL data for the non-strange vector and axial-vector spectral functions,\nwe find the n_f=3 values for {\\alpha}_s(m_{\\tau}^2) of 0.307(19) for\nfixed-order perturbation theory and 0.322(26) for contour-improved perturbation\ntheory, corresponding to n_f=5 values for {\\alpha}_s(M_Z^2) of 0.1169(25) and\n0.1187(32), respectively.",
        "positive": "Critical Momenta of Lattice Chiral Fermions: We determine the critical momenta for chiral fermions in the domain wall\nmodel recently suggested by Kaplan. For a wide range of domain wall masses $m$\nand Wilson couplings $r$ we explicitly exhibit the regions in momentum space\nwhere the fermions are chiral. We compare the critical momenta for the\ninfinitely large system with those obtained on a finite lattice."
    },
    {
        "anchor": "Staggered fermion approach to chiral gauge theories on the lattice: The staggered fermion approach to build models with chiral fermions is\nbriefly reviewed. The method is tested in a U(1) model with axial vector\ncoupling in two and four dimensions.",
        "positive": "Multi GPU Performance of Conjugate Gradient Algorithm with Staggered\n  Fermions: We report results of the performance test of GPUs obtained using the\nconjugate gradient (CG) algorithm for staggered fermions on the MILC fine\nlattice ($28^3 \\times 96$). We use GPUs of nVIDIA GTX 295 model for the test.\nWhen we turn off the MPI communication and use only a single GPU, the\nperformance is 35 giga flops in double precision, which corresponds to 47% of\nthe peak. When we turn on the MPI communication and use multi-GPUs, the\nperformance is reduced down to 12.3 giga flops. The data transfer through the\ninfiniband network and PCI-E bus I/O is a main bottle neck. We suggest two\npotential solutions of how to optimize the data transfer."
    },
    {
        "anchor": "Experiences with OpenMP in tmLQCD: An overview is given of the lessons learned from the introduction of\nmulti-threading using OpenMP in tmLQCD. In particular, programming style,\nperformance measurements, cache misses, scaling, thread distribution for hybrid\ncodes, race conditions, the overlapping of communication and computation and\nthe measurement and reduction of certain overheads are discussed. Performance\nmeasurements and sampling profiles are given for different implementations of\nthe hopping matrix computational kernel.",
        "positive": "The scalar pion form factor in two-flavor lattice QCD: We calculate the scalar form factor of the pion using two dynamical flavors\nof non-perturbatively $\\mathcal{O}(a)$-improved Wilson fermions, including both\nthe connected and the disconnected contribution to the relevant correlation\nfunctions. We employ the calculation of all-to-all propagators using stochastic\nsources and a generalized hopping parameter expansion. From the form factor\ndata at vanishing momentum transfer, $Q^2=0$, and two non-vanishing $Q^2$ we\nobtain an estimate for the scalar radius $\\left<r^2\\right>^\\pi_{_{\\rm S}}$ of\nthe pion at one value of the lattice spacing and for five different pion\nmasses. Using Chiral Perturbation Theory at next-to-leading order, we find\n$\\left<r^2\\right>^\\pi_{_{\\rm S}}=0.635\\pm0.016$ fm$^2$ at the physical pion\nmass (statistical error only). This is in good agreement with the\nphenomenological estimate from $\\pi\\pi$-scattering. The inclusion of the\ndisconnected contribution is essential for achieving this level of agreement."
    },
    {
        "anchor": "The inverted XY universality of the superconductivity phase transition: It has been conjectured that the phase transition in the Ginzburg-Landau\ntheory is dual to the XY model transition. We study numerically a particular\nlimit of the GL theory where this duality becomes exact, clarifying some of the\nproblems encountered in standard GL theory simulations. This may also explain\nthe failure of the superconductor experiments to observe the XY model scaling.",
        "positive": "Scaling Laws and Effective Dimension in Lattice SU(2) Yang-Mills Theory\n  with a Compactified Extra Dimension: Monte Carlo simulations are performed in a five-dimensional lattice SU(2)\nYang-Mills theory with a compactified extra dimension, and scaling laws are\nstudied. Our simulations indicate that as the compactification radius $R$\ndecreases, the confining phase spreads more and more to the weak coupling\nregime, and the effective dimension of the theory changes gradually from five\nto four. Our simulations also indicate that the limit $a_4 to 0$ with $R/a_4$\nkept fixed exists both in the confining and deconfining phases if $R/a_4$ is\nsmall enough, where $a_4$ is the lattice spacing in the four-dimensional\ndirection. We argue that the color degrees of freedom in QCD are confined only\nfor $R < R_{\\rm max}$, where a rough estimate shows that $1/R_{\\rm max}$ lies\nin the TeV range. Comments on deconstructing extra dimensions are given."
    },
    {
        "anchor": "Connected and leading disconnected hadronic light-by-light contribution\n  to the muon anomalous magnetic moment with physical pion mass: We report a lattice QCD calculation of the hadronic light-by-light\ncontribution to the muon anomalous magnetic moment at physical pion mass. The\ncalculation includes the connected diagrams and the leading,\nquark-line-disconnected diagrams. We incorporate algorithmic improvements\ndeveloped in our previous work. The calculation was performed on the $48^3\n\\times 96$ ensemble generated with a physical-pion-mass and a 5.5 fm spatial\nextent by the RBC and UKQCD collaborations using the chiral, domain wall\nfermion (DWF) formulation. We find $a_\\mu^{\\text{HLbL}} = 5.35 (1.35) \\times\n10^{- 10}$, where the error is statistical only. The finite-volume and finite\nlattice-spacing errors could be quite large and are the subject of on-going\nresearch. The omitted disconnected graphs, while expected to give a correction\nof order 10\\%, also need to be computed.",
        "positive": "A Method for Simulating Chiral Fermions on the Lattice: A method for simulating chiral gauge theories on the lattice is proposed,\ninvolving zeromodes on a topological defect. Lattice doublers may be decoupled\nin a gauge invariant manner, and flavor anomalies can be directly observed on a\nfinite lattice. (Requires harvmac)"
    },
    {
        "anchor": "Baryon axial charges from Chirally Improved fermions - first results: We present first results from dynamical Chirally Improved (CI) fermion\nsimulations for the axial charge $G_A$ of various hadrons. We work with 16^3x32\nlattices of spatial extent 2.4 fm and use the variational method with a\nsuitable basis of Jacobi-smeared interpolators to suppress contaminations from\nexcited states.",
        "positive": "Critical slowing down and the gradient flow coupling in the\n  Schr\u00f6dinger functional: We study the sensitivity of the gradient flow coupling to sectors of\ndifferent topological charge and its implications in practical situations.\nFurthermore, we investigate an alternative definition of the running coupling\nthat is expected to be less sensitive to the problems of the HMC algorithm to\nefficiently sample all topological sectors."
    },
    {
        "anchor": "$N\u03c0$-state contamination in lattice calculations of the nucleon\n  electromagnetic form factors: The nucleon-pion-state contribution to QCD two-point and three-point\nfunctions relevant for lattice calculations of the nucleon electromagnetic form\nfactors are studied in chiral perturbation theory. To leading order the results\ndepend on a few experimentally known low-energy constants only, and the\nnucleon-pion-state contribution to the form factors can be estimated. The\nnucleon-pion-state contribution to the electric form factor $G_{\\rm E}(Q^2)$ is\nat the +5 percent level for a source-sink separation of 2 fm, and it increases\nwith increasing momentum transfer $Q^2$. For the magnetic form factor the\nnucleon-pion-state contribution leads to an underestimation of $G_{\\rm M}(Q^2)$\nby about 5 percent that decreases with increasing $Q^2$. For smaller\nsource-sink separations that are accessible in present-day lattice simulations\nthe impact is larger, although the ChPT results may not be applicable for such\nsmall time separations. Still, a comparison with lattice data at $t\\approx 1.6$\nfm works reasonably well.",
        "positive": "Spectral quantities in thermal QCD: a progress report from the FASTSUM\n  collaboration: In order to study spectral quantities in thermal QCD, the FASTSUM\ncollaboration employs anisotropic lattice simulations with N_f=2+1 flavours of\nWilson fermions. Here we discuss our Generation 2 and Generation 2L ensembles,\nwhich differ in the pion mass. The focus is on observables related to the light\nquarks and chiral symmetry restoration."
    },
    {
        "anchor": "Universality Class of $O(N)$ Models: We point out that existing numerical data on the correlation length and\nmagnetic susceptibility suggest that the two dimensional $O(3)$ model with\nstandard action has critical exponent $\\eta=1/4$, which is inconsistent with\nasymptotic freedom. This value of $\\eta$ is also different from the one of the\nWess-Zumino-Novikov-Witten model that is supposed to correspond to the $O(3)$\nmodel at $\\theta=\\pi$.",
        "positive": "Tempered transitions between thimbles: Quantum field theories with complex actions cannot be investigated using\nimportance sampling due to the sign problem. One possible solution is to use\nthe holomorphic gradient flow, a method we introduced related to the Lefschetz\nthimbles idea. In many cases the probability distribution generated by this\nmethod is multi-modal and standard Monte-Carlo sampling fails. We propose an\nalgorithm that incorporates tempered proposals to solve this problem. We apply\nthis algorithm to the 0+1 dimensional Thirring model at finite density for a\nparameter set where standard sampling fails and show that tempered proposals\ncure this problem."
    },
    {
        "anchor": "Large center vortices and confinement in 3D Z(2) gauge theory: We study the role of large clusters of center vortices in producing\nconfinement in 3D Z(2) gauge theory. First, we modify each configuration of a\nMonte Carlo-generated ensemble in the confined phase by removing the largest\ncluster of center vortices, and show that the ensemble thus obtained does not\nconfine. Conversely, we show that removing all of the small clusters of center\nvortices and leaving the largest one only, confinement is preserved, albeit\nwith a string tension significantly smaller than the original one. Remarkably,\nalso the string corrections due to the quantum fluctuations of the confining\nflux tube are preserved by this transformation.",
        "positive": "N(N*) and Delta(Delta*) on the lattice: We investigate the mass spectrum of Nucleon and Delta (and its counterparts\nwith strange and charm), and their excited states, in quenched lattice QCD with\nexact chiral symmetry. For each light baryon, we use 23 masses to determine the\ncoefficients of the mass formula in quenched chiral perturbation theory. By\nchiral extrapolation to m_\\pi=135 MeV, we obtain M_N=958(26) MeV,\nM_{N*}=1553(42) MeV, M_{Delta}=1216(32) MeV and M_{Delta*}=1611(17) MeV, which\nare identified with N(939)P_{11},N(1535)S_{11}, Delta(1232)P_{33} and\nDelta(1620)S_{31} respectively. Further, we directly measure the masses of\nOmega^{-}, M_{Omega}=1648(60) MeV, and its excited state, M_{Omega*}=1935(48)\nMeV; as well as the triply charmed baryon Omega_{ccc}^{++},\nM_{Omega_{ccc}^{++}}=4931(22) MeV, and its excited state,\nM_{{\\Omega^{++}_{ccc}}^*}=5185(35) MeV."
    },
    {
        "anchor": "Is SU(3) gauge theory with 13 massless flavors conformal?: We use lattice simulations to study SU(3) gauge theory with 13 massless\nfermions in the fundamental representation. We present evidence that the theory\nis conformal with a non-zero infrared fixed point in the gauge coupling. We use\na newly-developed technique to calculate the mass anomalous dimension at the\nfixed point via step-scaling of the mode number, allowing us to take the\ncontinuum limit and compare to perturbative predictions. We comment on the\nrelevance of these findings to the extended search for the conformal window in\nthe fundamental representation and in particular 12 massless flavors.",
        "positive": "Lattice QCD calculations of nucleon transverse momentum-dependent parton\n  distributions using clover and domain wall fermions: We present a lattice QCD calculation of transverse momentum dependent parton\ndistribution functions (TMDs) of protons using staple-shaped Wilson lines. For\ntime-reversal odd observables, we calculate the generalized Sivers and\nBoer-Mulders transverse momentum shifts in SIDIS and DY cases, and for T-even\nobservables we calculate the transversity related to the tensor charge and the\ngeneralized worm-gear shift. The calculation is done on two different n_f=2+1\nensembles: domain-wall fermion (DWF) with lattice spacing 0.084 fm and pion\nmass of 297 MeV, and clover fermion with lattice spacing 0.114 fm and pion mass\nof 317 MeV. The results from those two different discretizations are consistent\nwith each other."
    },
    {
        "anchor": "Chiral perturbation theory for K+ to pi+ pi0 decay in the continuum and\n  on the lattice: In this paper we use one-loop chiral perturbation theory in order to compare\nlattice computations of the K+ to pi+ pi0 decay amplitude with the experimental\nvalue. This makes it possible to investigate three systematic effects that\nplague lattice computations: quenching, finite-volume effects, and the fact\nthat lattice computations have been done at unphysical values of the quark\nmasses and pion external momenta (only this latter effect shows up at tree\nlevel). We apply our results to the most recent lattice computation, and find\nthat all three effects are substantial. We conclude that one-loop corrections\nin chiral perturbation theory help in explaining the discrepancy between\nlattice results and the real-world value. We also revisit B_K, which is closely\nrelated to the K+ to pi+ pi0 decay amplitude by chiral symmetry.",
        "positive": "Gauge-invariant field-strength correlators for QCD in a magnetic\n  background: We consider the properties of the gauge-invariant two-point correlation\nfunctions of the gauge-field strengths for QCD in the presence of a magnetic\nbackground field. We discuss the general structure of the correlators in this\ncase and provide the results of an exploratory lattice study for $N_f = 2$ QCD\ndiscretized with unimproved staggered fermions. Our analysis provides evidence\nfor the emergence of anisotropies in the non-perturbative part of the\ncorrelators and for an increase of the gluon condensate as a function of the\nexternal magnetic field."
    },
    {
        "anchor": "Towards SU(2) invariant formulation of the monopole confinement\n  mechanism: The type of the vacuum is studied numerically in the maximally Abelian (MA)\ngauge and in the Landau (LA) gauge of SU(2) gluodynamics. The type of the\nvacuum is determined by a ratio between the dual coherence and the dual\npenetration lengths. The dual penetration length is determined from\ncorrelations between Wilson loops and electric fields in both gauges. The dual\ncoherence length is found from correlations between Wilson loops and\ndimension-2 operators both in the MA and the LA gauges. This determination of\nthe coherence length is supported by theoretical and numerical observation that\nthe dimension-2 gluon operators in the studied gauges have a strong correlation\nwith the monopole current determined in the MA gauge. We find numerically that\nthe dual penetration lengths and the dual coherence lengths in the LA and the\nMA gauges are almost the same. Therefore we conclude, that in both gauges the\ntype of the vacuum in the confinement phase is near to the border between the\ntype 1 and the type 2 dual superconductors.",
        "positive": "Freeze-out parameters: lattice meets experiment: We present our results for ratios of higher order fluctuations of electric\ncharge as functions of the temperature. These results are obtained in a system\nof 2+1 quark flavors at physical quark masses and continuum extrapolated. We\ncompare them to preliminary data on higher order moments of the net electric\ncharge distribution from the STAR collaboration. This allows us to determine\nthe freeze-out temperature and chemical potential from first principles. We\nalso show continuum-extrapolated results for ratios of higher order\nfluctuations of baryon number. These will allow to test the consistency of the\napproach, by comparing them to the corresponding experimental data (once they\nbecome available) and thus extracting the freeze-out parameters in an\nindependent way."
    },
    {
        "anchor": "Dynamical supersymmetry breaking and phase diagram of the lattice\n  Wess-Zumino model: We study dynamical supersymmetry breaking and the transition point by\nnon-perturbative lattice techniques in a class of two-dimensional N=1\nWess-Zumino model. The method is based on the calculation of rigorous lower\nbounds on the ground state energy density in the infinite-lattice limit. Such\nbounds are useful in the discussion of supersymmetry phase transition. The\ntransition point is determined with this method and then compared with recent\nresults based on large-scale Green Function Monte Carlo simulations with good\nagreement.",
        "positive": "QCD phase diagram: overview of recent lattice results: Two parameters that have a strong influence on the finite temperature QCD\ntransition, and play an important role in various physical scenarios are the\nquark density and the external magnetic field. The effect of these parameters\non the thermal properties of QCD is discussed, and an overview of the latest\nlattice results is given."
    },
    {
        "anchor": "Hunting for the Conformal Window: Undeniably, the imminent activity of LHC and the quest for the nature of\nphysics beyond the standard model have raised renewed interest in the conformal\nand quasi-conformal behaviour of gauge field theories with matter content.\nTheoretically driven questions seem to now acquire a strong experimental appeal\nand might guide us towards a more realistic string theory to field theory\nconnection, originally inspired by the AdS/CFT conjecture. In this brief\nreport, we discuss the state of the art of our search for the conformal window\nin the SU(3) colour-gauge theory with fermions in the fundamental\nrepresentation.",
        "positive": "The critical endpoint in the 2d U(1) gauge-Higgs model at topological\n  angle $\u03b8=\u03c0$: We study 2d U(1) gauge Higgs systems with a $\\theta$-term. For properly\ndiscretizing the topological charge as an integer we introduce a mixed group-\nand algebra-valued discretization (MGA scheme) for the gauge fields, such that\nthe charge conjugation symmetry at $\\theta = \\pi$ is implemented exactly. The\ncomplex action problem from the $\\theta$-term is overcome by exactly mapping\nthe partition sum to a worldline/worldsheet representation. Using Monte Carlo\nsimulation of the worldline/worldsheet representation we study the system at\n$\\theta = \\pi$ and show that as a function of the mass parameter the system\nundergoes a phase transition. Determining the critical exponents from a finite\nsize scaling analysis we show that the transition is in the 2d Ising\nuniversality class. We furthermore study the U(1) gauge Higgs systems at\n$\\theta = \\pi$ also with charge 2 matter fields, where an additional $Z_2$\nsymmetry is expected to alter the phase structure. Our results indicate that\nfor charge 2 a true phase transition is absent and only a rapid crossover\nseparates the large and small mass regions."
    },
    {
        "anchor": "Multi-hadron operators with all-to-all quark propagators: Hadron spectroscopy on dynamical configurations are faced with the\ndifficulties of dealing with the mixing of single particle states and\nmulti-hadron states (for large spatial volumes and light dynamical quarks\nmasses). It is conceivable that explicit multi-hadron interpolating operators\nwill be necessary for obtaining sufficiently good overlap onto multi-hadron\nstates in order to extract the low-lying excitation spectrum. We explore here\nthe feasibility of using four noise diluted all-to-all quark propagators in the\nconstruction of explicit two-hadron operators on quenched, anisotropic\nlattices. Our longer term goal is to use these operators on large anisotropic,\ndynamical configurations for hadron spectroscopy.",
        "positive": "NSPT study of the three-loop lattice gluon propagator in Landau gauge: By means of Numerical Stochastic Perturbation Theory (NSPT), we calculate the\nlattice gluon propagator up to three loops of perturbation theory in the limits\nof infinite volume and vanishing lattice spacing. Based on known anomalous\ndimensions and a parametrization of both the hypercubic symmetry group H(4) and\nfinite-size effects, we calculate the non-leading-log and non-logarithmic\ncontributions iteratively, starting with the first-loop expression."
    },
    {
        "anchor": "Nucleon axial coupling from Lattice QCD: We present state-of-the-art results from a lattice QCD calculation of the\nnucleon axial coupling, $g_A$, using M\\\"obius Domain-Wall fermions solved on\nthe dynamical $N_f = 2 + 1 + 1$ HISQ ensembles after they are smeared using the\ngradient-flow algorithm. Relevant three-point correlation functions are\ncalculated using a method inspired by the Feynman-Hellmann theorem, and\ndemonstrate significant improvement in signal for fixed stochastic samples. The\ncalculation is performed at five pion masses of $m_\\pi\\sim \\{400, 350, 310,\n220, 130\\}$~MeV, three lattice spacings of $a\\sim\\{0.15, 0.12, 0.09\\}$~fm, and\nwe do a dedicated volume study with $m_\\pi L\\sim\\{3.22, 4.29, 5.36\\}$. Control\nover all relevant sources of systematic uncertainty are demonstrated and\nquantified. We achieve a preliminary value of $g_A = 1.285(17)$, with a\nrelative uncertainty of 1.33\\%.",
        "positive": "Magnetic polarizability of a charged pion from four-point functions in\n  lattice QCD: Electromagnetic dipole polarizabilities are fundamental properties of a\nhadron that represent its resistance to deformation under external fields. For\na charged hadron, the presence of acceleration and Landau levels complicates\nthe isolation of its deformation energy in the conventional background field\nmethod. In this work, we explore a general method based on four-point functions\nin lattice QCD that takes into account all photon, quark and gluon\ninteractions. The electric polarizability ($\\alpha_E$) has been determined from\nthe method in a previous proof-of-principle simulation. Here we focus on the\nmagnetic polarizability ($\\beta_M$) using the same quenched Wilson action on a\n$24^3\\times 48$ lattice at $\\beta=6.0$ with pion mass from 1100 to 370 MeV. The\nresults from the connected diagrams show a large cancellation between the\nelastic and inelastic contributions, leading to a relatively small and negative\nvalue for $\\beta_M$ consistent with chiral perturbation theory. We also discuss\nthe mechanism for $\\alpha_E+\\beta_M$ from combining the two studies."
    },
    {
        "anchor": "Nonperturbative Regulator for Chiral Gauge Theories?: We propose a nonperturbative gauge invariant regulator for d-dimensional\nchiral gauge theories on the lattice. The method involves simulating domain\nwall fermions in d + 1 dimensions with quantum gauge fields that reside on one\nd-dimensional surface and are extended into the bulk via gradient flow. The\nresult is a theory of gauged fermions plus mirror fermions, where the mirror\nfermions couple to the gauge fields via a form factor that becomes\nexponentially soft with the separation between domain walls. The resultant\ntheory has a local d-dimensional interpretation only if the chiral fermion\nrepresentation is anomaly free. A physical realization of this construction\nwould imply the existence of mirror fermions in the standard model that are\ninvisible except for interactions induced by vacuum topology, and which could\ngravitate differently than conventional matter.",
        "positive": "Aharonov-Bohm effect, Center Monopoles and Center Vortices in SU(2)\n  Lattice Gluodynamics: SU(2) gluodynamics is investigated numerically and analytically in the\n(Indirect) Maximal Center gauge at finite temperature. The center vortices are\nshown to be condensed in the confinement phase and dilute in the deconfinement\nphase. A new physical object, center monopole, is constructed. We show that the\ncenter monopole condensate is the order parameter of deconfinement phase\ntransition. The linking of the vortex worldsheets and quark trajectories is\nidentified with the Aharonov-Bohm interaction in an effective Abelian Higgs\ntheory. We conclude that the confinement in the Maximal Center gauge can be\nexplained by a new mechanism called \"the real superconductor mechanism\"."
    },
    {
        "anchor": "The complete lowest order chiral Lagrangian from a little box: We recently performed a pilot study determining the parameters of the leading\norder chiral Lagrangian from distributions of the eigenvalues of a quenched\nDirac operator coupled to an imaginary isospin chemical potential. We\ncomplement a quick survey of our recent preprint arXiv:0708.1731 [hep-lat] by\naddressing some points raised during discussions at the conference.",
        "positive": "The deconfinement transition in SU(N) gauge theories: We investigate the properties of the deconfinement transition in SU(4) and\nSU(6) gauge theories. We find that it is a `normal' first order transition in\nboth cases, from which we conclude that the transition is first order in the\nN->infinity limit. Comparing our preliminary estimates of the continuum values\nof Tc/sqrt(K) with existing values for SU(2) and SU(3) demonstrates a weak\ndependence on N for all values of N."
    },
    {
        "anchor": "Numerical study of the $\\mathcal{N}=2$ Landau--Ginzburg model: It is believed that the two-dimensional massless $\\mathcal{N}=2$ Wess--Zumino\nmodel becomes the $\\mathcal{N}=2$ superconformal field theory (SCFT) in the\ninfrared (IR) limit. We examine this theoretical conjecture of the\nLandau--Ginzburg (LG) description of the $\\mathcal{N}=2$ SCFT by numerical\nsimulations on the basis of a supersymmetric-invariant momentum-cutoff\nregularization. We study a single supermultiplet with cubic and quartic\nsuperpotentials. From two-point correlation functions in the IR region, we\nmeasure the scaling dimension and the central charge, which are consistent with\nthe conjectured LG description of the $A_2$ and $A_3$ minimal models,\nrespectively. Our result supports the theoretical conjecture and, at the same\ntime, indicates a possible computational method of correlation functions in the\n$\\mathcal{N}=2$ SCFT from the LG description.",
        "positive": "Improved Sampling Algorithms in Lattice QCD: Reverse Monte Carlo (RMC) is an algorithm that incorporates stochastic\nmodification of the action as part of the process that updates the fields in a\nMonte Carlo simulation. Such update moves have the potential of lowering or\neliminating potential barriers that may cause inefficiencies in exploring the\nfield configuration space. The highly successful Cluster algorithms for spin\nsystems can be derived from the RMC framework. In this work we apply RMC ideas\nto pure gauge theory, aiming to alleviate the critical slowing down observed in\nthe topological charge evolution as well as other long distance observables. We\npresent various formulations of the basic idea and report on our numerical\nexperiments with these algorithms."
    },
    {
        "anchor": "Topological Susceptibility on Dynamical Staggered Fermion Configurations: The topological susceptibility is one of the few physical quantities that\ndirectly measure the properties of the QCD vacuum. Chiral perturbation theory\npredicts that in the small quark mass limit the topological susceptibility\ndepends quadratically on the pion mass, approaching zero in the chiral limit.\nLattice calculations have difficulty reproducing this behavior. In this paper\nwe study the topological susceptibility on dynamical staggered fermion\nconfigurations. Our results indicate that the lattice spacing has to be small,\naround a~0.1fm for thin link staggered fermion actions to show the expected\nchiral behavior. Our preliminary result indicates that fat link fermions, on\nthe other hand, reproduce the theoretical expectations even on lattices with\na~0.17fm. We argue that this is due to the improved flavor symmetry of fat link\nfermionic actions.",
        "positive": "Thermal D mesons from anisotropic lattice QCD: We present results for correlators and spectral functions of open charm\nmesons using 2+1 flavours of clover fermions on anisotropic lattices. The D\nmesons are found to dissociate close to the deconfinement crossover temperature\nTc. Our preliminary results suggest a shift in the thermal D meson mass below\nTc. Mesons containing strange quarks exhibit smaller thermal modifications than\nthose containing light quarks."
    },
    {
        "anchor": "Evidence for O(2) universality at the finite temperature transition for\n  lattice QCD with 2 flavours of massless staggered quarks: We simulate lattice QCD with 2 flavours of massless quarks on lattices of\ntemporal extent N_t=8, to study the finite temperature transition from hadronic\nmatter to a quark-gluon plasma. A modified action which incorporates an\nirrelevant chiral 4-fermion interaction is used, which allows simulations at\nzero quark mass. We obtain excellent fits of the chiral condensates to the\nmagnetizations of a 3-dimensional O(2) spin model on lattices small enough to\nmodel the finite size effects. This gives predictions for correlation lengths\nand chiral susceptibilities from the corresponding spin-model quantities. These\nare in good agreement with our measurements over the relevant range of\nparameters. Binder cumulants are measured, but the errors are too large to draw\ndefinite conclusions. From the properties of the O(2) spin model on the\nrelatively small lattices with which we fit our `data', we can see why earlier\nattempts to fit staggered lattice data to leading-order infinite-volume scaling\nfunctions, as well as finite size scaling studies, failed and led to erroneous\nconclusions.",
        "positive": "Interplay of Monopoles and P-Vortices: We show that P-Vortices in the confinement phase of SU(2) lattice gauge\ntheory form one large percolating (infrared) cluster and a number of small\n(ultraviolet) clusters. We discuss the interrelation of clusters of monopoles\nin the maximal Abelian projection with clusters of P-vortices. To extract\nP-vortices we use both direct and indirect central projections and find\nqualitatively similar results."
    },
    {
        "anchor": "The decay of unstable strings in SU(2) Yang-Mills theory: We investigate the stability of strings connecting charges Q in the\nrepresentation {2Q+1} of SU(2) Yang-Mills theory in (2+1) dimensions. While the\nfundamental {2}-string between two charges Q=1/2 is unbreakable and stable, the\nstring connecting static charges transforming under any other representation\nQ>1/2 is unstable and decays. A charge Q=1 can be completely screened by gluons\nand so the adjoint {3}-string ultimately breaks. A charge Q=3/2 can be only\npartially screened to a fundamental charge Q=1/2. Thus, stretching a {4}-string\nbeyond a critical length, it decays into the stable {2}-string by gluon pair\ncreation. The complete breaking of a {5}-string happens in two steps, it first\ndecays into a {3}-string and then breaks completely. A phenomenological\nconstituent gluon model provides a good quantitative description of the energy\nof the screened charges at the ends of an unstable string.",
        "positive": "Is there a third-order phase transition in quenched QCD?: We discuss the connection between the contributions of large field\nconfigurations and the large order behavior of perturbation theory. For\nquenched QCD, the sensitivity of the average plaquette to a removal of large\nfield configurations has a narrow peak near beta=5.6. Various analysis of the\norder 10 weak coupling series for the plaquette give robust indications for a\nsingularity in the third derivative of the free energy (second derivative of\nthe plaquette) with respect to beta, near beta = 5.7. We report results of\nnumerical calculations. The peak in the third derivative of the free energy\npresent on 4^4 lattices disappears if the size of the lattice is increased\nisotropically up to a 10^4 lattice. On the other hand, on 4xL^3 lattices, it\npersists when L increases. The location of the peak coincides with the onset of\na non-zero average for the Polyakov loop and seems related to the finite\ntemperature transition. We also discuss the discrepancy between the\nperturbative series and the numerical values of the plaquette."
    },
    {
        "anchor": "Chiral Fermions on the Lattice: The Overlap-Dirac operator provides a lattice regularization of massless\nvector gauge theories with an exact chiral symmetry. Practical implementations\nof this operator and recent results in quenched QCD using this Overlap-Dirac\noperator are reviewed.",
        "positive": "Baryon magnetic moments in the external field method: We present a calculation of the magnetic moments of the baryon octet and\ndecuplet using the external field method and standard Wilson gauge and fermion\nactions in the quenched approximation. Progressively smaller static magnetic\nfields are introduced on a $24^4$ latticeat beta=6.0 and the pion mass is\nprobed down to about 500 MeV. Magnetic moments are extracted from the linear\nresponse of the masses to the external field."
    },
    {
        "anchor": "Nonperturbatively Improved Hadron Spectroscopy Near the Continuum Limit: We report the results of our quenched lattice simulations of the Wilson\naction with a nonperturbatively determined clover term at beta=6.2 and compare\nthem with those of the standard Wilson action at the same beta value.",
        "positive": "Finite density QCD with a canonical approach: We present a canonical method where the properties of QCD are directly\nobtained as a function of the baryon density rho, rather than the chemical\npotential mu. We apply this method to the determination of the phase diagram of\nfour-flavor QCD. For a pion mass m_pi \\sim 350 MeV, the first-order transition\nbetween the hadronic and the plasma phase gives rise to a co-existence region\nin the T-rho plane, which we study in detail, including the associated\ninterface tension. We obtain accurate results for systems containing up to 30\nbaryons and quark chemical potentials mu up to 2 T. Our T-mu phase diagram\nagrees with the literature when mu/T \\lesssim 1. At larger chemical potential,\nwe observe a ``bending down'' of the phase boundary. We compare the free energy\nin the confined and deconfined phase with predictions from a hadron resonance\ngas and from a free massless quark gas respectively."
    },
    {
        "anchor": "A Mixed Action Analysis of $\u03b7$ and $\u03b7'$ Mesons: We study $\\eta$ and $\\eta'$ mesons and their mixing angle in a mixed action\napproach with so-called Osterwalder-Seiler valence quarks on a Wilson twisted\nmass sea. The gauge configurations have been generated by ETMC for $N_f=2+1+1$\ndynamical quark flavours and for three values of the lattice spacing. The main\nresults are that differences in between the mixed action and the unitary\napproach vanish towards the continuum limit with the expected rate of\n$\\mathcal{O}(a^2)$. The individual size of the lattice artifacts depends,\nhowever, strongly on the observable used to match unitary and valence actions.\nMoreover, we show that for the $\\eta$ mass valence and valence plus sea quark\nmass dependence differ significantly. Hence, in this case a re-tuning of the\nsimulation parameters in the valence sector only is not sufficient to\ncompensate for mismatches in the original quark masses.",
        "positive": "Entanglement entropy of SU(3) Yang-Mills theory: We calculate the entanglement entropy using a SU(3) quenched lattice gauge\nsimulation. We find that the entanglement entropy scales as $1/l^2$ at small\n$l$ as in the conformal field theory. Here $l$ is the size of the system, whose\ndegrees of freedom is left after the other part are traced out. The derivative\nof the entanglement entropy with respect to $l$ hits zero at about $l^{\\ast} =\n0.6 \\sim 0.7$ [fm] and vanishes above the length. It may imply that the\nYang-Mills theory has the mass gap of the order of $1/l^{\\ast}$. Within our\nstatistical errors, no discontinuous change can be seen in the entanglement\nentropy. We discuss also a subtle point appearing in gauge systems when we\ndivide a system with cuts."
    },
    {
        "anchor": "The flat phase of fixed-connectivity membranes: The statistical mechanics of flexible two-dimensional surfaces (membranes)\nappears in a wide variety of physical settings. In this talk we discuss the\nsimplest case of fixed-connectivity surfaces. We first review the current\ntheoretical understanding of the remarkable flat phase of such membranes. We\nthen summarize the results of a recent large scale Monte Carlo simulation of\nthe simplest conceivable discrete realization of this system \\cite{BCFTA}. We\nverify the existence of long-range order, determine the associated critical\nexponents of the flat phase and compare the results to the predictions of\nvarious theoretical models.",
        "positive": "Heavy-light mesons in 2+1 flavor lattice QCD: Heavy-light meson system is investigated using the relativistic heavy quark\naction on the 2+1 dynamical flavor PACS-CS configurations at the lattice\nspacing $a^{-1}=2.2$ GeV and the spatial extent L=3 fm. Dynamical up-down and\nstrange quark masses as well as the valence charm quark mass are set around\ntheir physical values. We measure the charm-$ud$ and charm-strange meson masses\nand decay constants. Our results are consistent with the experimental values\nexcept the hyperfine splitting of the charm-strange meson. We also estimate the\nCKM matrix elements in the second row."
    },
    {
        "anchor": "Electromagnetic and strong isospin-breaking corrections to the muon $g -\n  2$ from Lattice QCD+QED: We present a lattice calculation of the leading-order electromagnetic and\nstrong isospin-breaking corrections to the hadronic vacuum polarization (HVP)\ncontribution to the anomalous magnetic moment of the muon. We employ the gauge\nconfigurations generated by the European Twisted Mass Collaboration (ETMC) with\n$N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a\n\\simeq 0.062, 0.082, 0.089$ fm) with pion masses between $\\simeq 210$ and\n$\\simeq 450$ MeV. The results are obtained adopting the RM123 approach in the\nquenched-QED approximation, which neglects the charges of the sea quarks. Quark\ndisconnected diagrams are not included. After the extrapolations to the\nphysical pion mass and to the continuum and infinite-volume limits the\ncontributions of the light, strange and charm quarks are respectively equal to\n$\\delta a_\\mu^{\\rm HVP}(ud) = 7.1 ~ (2.5) \\cdot 10^{-10}$, $\\delta a_\\mu^{\\rm\nHVP}(s) = -0.0053 ~ (33) \\cdot 10^{-10}$ and $\\delta a_\\mu^{\\rm HVP}(c) =\n0.0182 ~ (36) \\cdot 10^{-10}$. At leading order in $\\alpha_{em}$ and $(m_d -\nm_u) / \\Lambda_{QCD}$ we obtain $\\delta a_\\mu^{\\rm HVP}(udsc) = 7.1 ~ (2.9)\n\\cdot 10^{-10}$, which is currently the most accurate determination of the\nisospin-breaking corrections to $a_\\mu^{\\rm HVP}$.",
        "positive": "Lattice Dirac operators with chiral chemical potential: This paper has been withdrawn by the author."
    },
    {
        "anchor": "Two-photon decay of the neutral pion in lattice QCD: We perform non-perturbative calculation of the \\pi^0 to {\\gamma}{\\gamma}\ntransition form factor and the associated decay width using lattice QCD. The\namplitude for two-photon final state, which is not an eigenstate of QCD, is\nextracted through an Euclidean time integral of the relevant three-point\nfunction. We utilize the all-to-all quark propagator technique to carry out\nthis integral as well as to include the disconnected quark diagram\ncontributions. The overlap fermion formulation is employed on the lattice to\nensure exact chiral symmetry on the lattice. After examining various sources of\nsystematic effects except for possible discretization effect, we obtain\n\\Gamma=7.83(31)(49) eV for the pion decay width, where the first error is\nstatistical and the second is our estimate of the systematic error.",
        "positive": "Learning trivializing flows: The recent introduction of machine learning techniques, especially\nnormalizing flows, for the sampling of lattice gauge theories has shed some\nhope on improving the sampling efficiency of the traditional HMC algorithm.\nNaive use of normalizing flows has been shown to lead to bad scaling with the\nvolume. In this talk we propose using local normalizing flows at a scale given\nby the correlation length. Even if naively these transformations have a small\nacceptance, when combined with the HMC algorithm lead to algorithms with high\nacceptance, and also with reduced autocorrelation times compared with HMC.\nSeveral scaling tests are performed in the $\\phi^{4}$ theory in 2D."
    },
    {
        "anchor": "Gribov Copies in the Minimal Landau Gauge: the Influence on Gluon and\n  Ghost Propagators: We study the influence of Gribov copies on gluon and ghost propagators,\nevaluated numerically in pure SU(2) lattice gauge theory in the minimal Landau\ngauge. Simulations are done at four different values of $\\beta$ (namely $\\beta$\n= 0, 0.8, 1.6 and 2.7) and for volumes up to $16^4$ (up to $24^4$ at $\\beta$ =\n1.6). For the gluon propagator, Gribov noise seems to be of the order of\nmagnitude of the numerical accuracy, even at very small values of the coupling\n$\\beta$. On the contrary, for the ghost propagator, Gribov noise is clearly\nobservable for the three values of $\\beta$ in the strong-coupling regime. In\nparticular, data corresponding to the minimal Landau gauge are always smaller\nthan those obtained in a generic Landau gauge. This result can be qualitatively\nexplained.",
        "positive": "Pion-pole contribution to HLbL from twisted mass lattice QCD at the\n  physical point: We report on our computation of the pion transition form factor ${\\cal\nF}_{P\\rightarrow \\gamma^*\\gamma^*}$ from twisted mass lattice QCD in order to\ndetermine the numerically dominant light pseudoscalar pole contribution in the\nhadronic light-by-light scattering contribution to the anomalous magnetic\nmoment of the muon $a_\\mu =(g-2)_\\mu$. The pion transition form factor is\ncomputed directly at the physical point. We present first results for our\nestimate of the pion-pole contribution with kinematic setup for the pion at\nrest."
    },
    {
        "anchor": "Fractionally charged Wilson loops as a probe of $\u03b8$-dependence in\n  $CP^{N-1}$ sigma models: Instantons vs. large N: The behavior of Wilson loops with fractional charge is used to study the\n$\\theta$-dependence of the free energy density $\\epsilon(\\theta)$ for the\n$CP^1$, $CP^5$, and $CP^9$ sigma models in two spacetime dimensions. The\nfunction $\\epsilon(\\theta)$ is extracted from the area law for a Wilson loop of\ncharge $q=\\theta/2\\pi$. For $CP^1$, $\\epsilon(\\theta)$ is smooth in the region\n$\\theta\\approx\\pi$ and well-described by a dilute instanton gas throughout the\nrange $0<\\theta<2\\pi$. For $CP^5$ and $CP^9$ the energy exhibits a clear cusp\nand evidence for discrete, degenerate vacua at $\\theta = \\pi$, as expected from\nlarge $N$ arguments. For $CP^9$ the $\\theta$-dependence is in good quantitative\nagreement with the leading order large $N$ prediction\n$\\epsilon(\\theta)={1/2}\\chi_t\\theta^2$ throughout the range $0<\\theta<\\pi$.",
        "positive": "Compact U(1) Gauge Theory on Lattices with Trivial Homotopy Group: We study the pure gauge model on a lattice manifold with trivial fundamental\nhomotopy group, homotopically equivalent to an $S_4$. Monopole loops may\nfluctuate freely on that lattice without restrictions due to the boundary\nconditions. For the original Wilson action on the hypertorus there is an\nestablished two-state signal in energy distribution functions which disappears\nfor the new geometry. Our finite size scaling analysis suggests stringent upper\nbounds on possible discontinuities in the plaquette action. However, no\nconsistent asymptotic finite size scaling behaviour is observed."
    },
    {
        "anchor": "Multicanonical Cluster Algorithm and the 2-D 7-State Potts Model: I present a hybrid-like two-step algorithm, which combines a microcanonical\nupdate of a spin system using demons, with a multicanonical demon refresh. The\nalgorithm is free from the supercritical slowing down that burdens the\ncanonical methods: the exponential increase of the tunnelling time between the\nmetastable states in the first-order phase transitions, when the volume of the\nsystem is increased. The demons act as a buffer between the multicanonical heat\nbath and the spin system, allowing the spin system to be updated with any\nmicrocanonical demon procedure, including cluster methods. The cluster\nalgorithm is demonstrated with the 2-dimensional 7-state Potts model, using\nvolumes up to $128^2$. The tunnelling time is found to increase as $L^{1.82}$,\nwhere $L$ is the linear dimension of the system.",
        "positive": "Complex Langevin simulations for $PT$-symmetric models: Self-interacting scalar quantum field theories possessing $PT$-symmetry are\nphysically admissible since their energy spectrum is real and bounded below.\nHowever, models with $PT$-invariant potentials can have complex actions in\ngeneral and a non-perturbative study of such systems using methods based on\ntraditional Monte Carlo is hindered due to numerical sign problem. In this work\nwe employ complex Langevin based on stochastic quantization to study\ntwo-dimensional scalar field theories, including the ones exhibiting\n$PT$-symmetry. We also study the simplest supersymmetric version of these\nsystems and address the question on dynamical supersymmetry breaking."
    },
    {
        "anchor": "Nucleon isovector momentum fraction, helicity and transversity moment\n  using Lattice QCD: We present our recent high precision calculations (Phys. Rev. D102 (2020)\nno.5, 054512 and JHEP 04 (2021) 044, JHEP 21 (2020) 004) of the first moment of\nnucleon isovector polarized, unpolarized and transversity distributions, i.e.,\nmomentum fraction, helicity and transversity moment, respectively. We use the\nstandard method for the calculation of these moments (via matrix elements of\ntwist two operators), and carry out a detailed analysis of the sources of\nsystematic uncertainty, in particular of excited state contributions. Our\ncalculations have been performed using two different lattice setups\n(Clover-on-HISQ and Clover-on-Clover), each with several ensembles. They give\nconsistent results that are in agreement with global fit analyses.",
        "positive": "Topological Fluctuations in Dense Matter with Two Colors: We study the topological charge fluctuations of an SU(2) lattice gauge theory\ncontaining both N_f=2 and 4 flavors of Wilson fermion, at low temperature with\nnon-zero chemical potential $\\mu$. The topological susceptibility, chi_T, is\nused to characterize differing physical regimes as mu is varied between the\nonset of matter at mu_o and and color deconfinement at mu_d. Suppression of\ninstantons by matter via Debye screening is also investigated, revealing\neffects not captured by perturbative predictions. In particular, the breaking\nof scale invariance leads to the mean instanton size rho becoming mu-dependent\nin the regime between onset and deconfinement, with a scaling rho~1/mu^2 over\nthe range mu_o<mu<mu_d, resulting in an enhancement of chi_T immediately above\nonset."
    },
    {
        "anchor": "Gravitational form factors of the proton from lattice QCD: The gravitational form factors (GFFs) of a hadron encode fundamental aspects\nof its structure, including its shape and size as defined from e.g., its energy\ndensity. This work presents a determination of the flavor decomposition of the\nGFFs of the proton from lattice QCD, in the kinematic region $0\\leq -t\\leq\n2~\\text{GeV}^2$. The decomposition into up-, down-, strange-quark, and gluon\ncontributions provides first-principles constraints on the role of each\nconstituent in generating key proton structure observables, such as its\nmechanical radius, mass radius, and $D$-term.",
        "positive": "Possible Consequences of Conjectural Periodicity of Spectrum of Lattice\n  Dirac Operator: Some consequences which follow from the periodicity assumption for spectral\ndensity of Wilson--Dirac operator are studied. Such an assumption allows to\nobtain simple representations for quark propagator, which reveals an important\nrole of $m\\leftrightarrow -m$ symmetry. It is argued that this symmetry is\nrestored when the mirror fermion mass $m_r$ tended to infinity. The constrains\non zero modes of Wilson--Dirac operator in a toy model approximation are also\ndiscussed."
    },
    {
        "anchor": "Calculation of the continuum--lattice HQET matching for the complete\n  basis of four--fermion operators: reanalysis of the $B^{0}$-$\\bar{B}^{0}$\n  mixing: In this work, we find the expressions of continuum HQET four-fermion\noperators in terms of lattice operators in perturbation theory. To do so, we\ncalculate the one--loop continuum--lattice HQET matching for the complete basis\nof $\\Delta B=2$ and $\\Delta B=0$ operators (excluding penguin diagrams),\nextending and completing previous studies. We have also corrected some errors\nin previous evaluations of the matching for the operator $O_{LL}$. Our results\nare relevant to the lattice computation of the values of unknown hadronic\nmatrix elements which enter in many very important theoretical predictions in\n$B$--meson phenomenology: $B^{0}$-$\\bar{B}^{0}$ mixing, $\\tau_{B}$ and\n$\\tau_{B_{s}}$ lifetimes, SUSY effects in $\\Delta B=2$ transitions and the\n$B_{s}$ width difference $\\Delta \\Gamma_{B_{s}}$. We have reanalyzed our\nlattice data for the $B_{B}$ parameter of the $B^{0}$-$\\bar{B}^{0}$ mixing on\n600 lattices of size $24^{3}\\times 40$ at $\\beta=6.0$ computed with the\nSW-Clover and HQET lattice actions. We have used the correct lattice--continuum\nmatching factors and boosted perturbation theory with tadpole improved\nheavy--light operators to reduce the systematic error in the evaluation of the\nrenormalization constants. Our best estimate of the renormalization scale\nindependent $B$--parameter is $\\hat{B}_{B} = 1.29 \\pm 0.08 \\pm 0.06$, where the\nfirst error is statistical and the second is systematic coming from the\nuncertainty in the determination of the renormalization constants. Our result\nis in good agreement with previous results obtained by extrapolating Wilson\ndata. As a byproduct, we also obtain the complete one--loop anomalous dimension\nmatrix for four--fermion operators in the HQET.",
        "positive": "Signals of confinement in Green functions of SU(2) Yang-Mills theory: The vortex picture of confinement is employed to explore the signals of\nconfinement in Yang-Mills Green functions. By using SU(2) lattice gauge theory,\nit has been well established that the removal of the center vortices from the\nlattice configurations results in the loss of confinement. The running coupling\nconstant, the gluon and the ghost form factors are studied in Landau gauge for\nboth cases, the full and the vortex removed theory. In the latter case, a\nstrong suppression of the running coupling constant and the gluon form factor\nat low momenta is observed. At the same time, the singularity of the ghost form\nfactor at vanishing momentum disappears. This observation establishes an\nintimate correlation between the ghost singularity and confinement. The result\nalso shows that a removal of the vortices generates a theory for which\nZwanziger's horizon condition for confinement is no longer satisfied."
    },
    {
        "anchor": "Resummed lattice QCD equation of state at finite baryon density:\n  strangeness neutrality and beyond: We calculate a resummed equation of state with lattice QCD simulations at\nimaginary chemical potentials. This work presents a generalization of the\nscheme introduced in 2102.06660 to the case of non-zero $\\mu_S$, focusing on\nthe line of strangeness neutrality. We present results up to $\\mu_B/T \\leq 3.5$\non the strangeness neutral line $\\left\\langle S \\right\\rangle = 0$ in the\ntemperature range $130 \\rm{MeV} \\leq T \\leq 280 \\rm{MeV}$. We also extrapolate\nthe finite baryon density equation of state to small non-zero values of the\nstrangeness-to-baryon ratio $R=\\left\\langle S \\right\\rangle / \\left\\langle B\n\\right\\rangle$. We perform a continuum extrapolation using lattice simulations\nof the 4stout-improved staggered action with 8, 10, 12 and 16 timeslices.",
        "positive": "Three-body dynamics of the $a_1(1260)$ resonance from lattice QCD: Resonant hadronic systems often exhibit a complicated decay pattern in which\nthree-body dynamics play a relevant or even dominant role. In this work we\nfocus on the $a_1(1260)$ resonance. For the first time, the pole position and\nbranching ratios of a three-body resonance are calculated from lattice QCD\nusing one-, two-, and three-meson interpolators and a three-body finite-volume\nformalism extended to spin and coupled channels. This marks a new milestone for\nab-initio studies of ordinary resonances along with hybrid and exotic hadrons\ninvolving three-body dynamics."
    },
    {
        "anchor": "Lattice QCD with Classical and Quantum Electrodynamics: We are doubtlessly familiar with some edition of Jackson's tome on\nelectrodynamics, and Schwinger's calculation of the anomalous magnetic moment\nof the electron in QED. From the perspective of strong interactions, however,\nelectromagnetic effects usually amount to negligible contributions. Despite\nthis fact, electromagnetic probes have always been a fundamental source for our\nknowledge of QCD experimentally. Elastic scattering of electrons off nucleons\nprovides us a window to their distributions of charge and magnetism. To account\nfor the spectrum of QCD at the percent level, moreover, we need isospin\nbreaking introduced from both quark masses and electric charges. This overview\nconcerns some of the prospects and progress of studying electromagnetic effects\nin QCD. Our focus is divided between classical and quantum effects. In\nclassical electromagnetic fields, the dynamical response of QCD to external\nconditions can be investigated. The vacuum and hadrons alike should be viewed\nas media which respond to external fields: both magnetize and polarize in\nmagnetic fields, for example. At the quantum level, electromagnetism and QCD\nrenormalize each other. In the era of high precision lattice computations, both\nstrong and electromagnetic contributions must be accounted for to make\npredictions at the percent level.",
        "positive": "$\u039b_b \\to p \\ell^- \\bar\u03bd_\\ell$ and $\u039b_b \\to \u039b_c\n  \\ell^- \\bar\u03bd_\\ell$ form factors from lattice QCD with relativistic heavy\n  quarks: Measurements of the $\\Lambda_b \\to p \\ell^- \\bar{\\nu}_\\ell$ and $\\Lambda_b\n\\to \\Lambda_c \\ell^- \\bar{\\nu}_\\ell$ decay rates can be used to determine the\nmagnitudes of the CKM matrix elements $V_{ub}$ and $V_{cb}$, provided that the\nrelevant hadronic form factors are known. Here we present a precise calculation\nof these form factors using lattice QCD with 2+1 flavors of dynamical\ndomain-wall fermions. The $b$ and $c$ quarks are implemented with relativistic\nheavy-quark actions, allowing us to work directly at the physical heavy-quark\nmasses. The lattice computation is performed for six different pion masses and\ntwo different lattice spacings, using gauge-field configurations generated by\nthe RBC and UKQCD collaborations. The $b \\to u$ and $b \\to c$ currents are\nrenormalized with a mostly nonperturbative method. We extrapolate the form\nfactor results to the physical pion mass and the continuum limit, parametrizing\nthe $q^2$-dependence using $z$-expansions. The form factors are presented in\nsuch a way as to enable the correlated propagation of both statistical and\nsystematic uncertainties into derived quantities such as differential decay\nrates and asymmetries. Using these form factors, we present predictions for the\n$\\Lambda_b \\to p \\ell^- \\bar{\\nu}_\\ell$ and $\\Lambda_b \\to \\Lambda_c \\ell^-\n\\bar{\\nu}_\\ell$ differential and integrated decay rates. Combined with\nexperimental data, our results enable determinations of $|V_{ub}|$, $|V_{cb}|$,\nand $|V_{ub}/V_{cb}|$ with theory uncertainties of 4.4%, 2.2%, and 4.9%,\nrespectively."
    },
    {
        "anchor": "Determining the QCD coupling from lattice vacuum polarization: The QCD coupling appears in the perturbative expansion of the current-current\ntwo-point (vacuum polarization) function. Any lattice calculation of vacuum\npolarization is plagued by several competing non-perturbative effects at small\nmomenta and by discretization errors at large momenta. We work in an\nintermediate region, computing the vacuum polarization for many off-axis\nmomentum directions on the lattice. Having many momentum directions provides a\nway to monitor and account for lattice artifacts. Our results are competitive\nwith, and have certain systematic advantages over, the alternate\nphenomenological determination of the strong coupling from the same light quark\nvacuum polarization produced by sum rule analyses of hadronic tau decay data.",
        "positive": "Lattice QCD at finite density via a new canonical approach: We carry out a finite density calculation based on a canonical approach which\nis designed to address the overlap problem. Two degenerate flavor simulations\nare performed using Wilson gauge action and Wilson fermions on $4^4$ lattices,\nat temperatures close to the critical temperature $T_c\\approx 170\\MeV$ and\nlarge densities (5 to 20 times nuclear matter density). In this region, we find\nthat the algorithm works well. We compare our results with those from other\napproaches."
    },
    {
        "anchor": "Grassmann tensor renormalization group for one-flavor lattice\n  Gross-Neveu model with finite chemical potential: We apply the Grassmann tensor renormalization group (GTRG) to the one-flavor\nlattice Gross-Neveu model in the presence of chemical potential. We compute the\nfermion number density and its susceptibility and confirm the validity of GTRG\nfor the finite density system. We introduce a method analogous to the\nreweighting method for Monte Carlo method and test it for some parameters.",
        "positive": "The isovector axial form factor of the nucleon from lattice QCD: The isovector axial form factor of the nucleon plays a key role in\ninterpreting data from long-baseline neutrino oscillation experiments. We\nperform a lattice-QCD based calculation of this form factor, introducing a new\nmethod to directly extract its $z$-expansion from lattice correlators. Our\nfinal parametrization of the form factor, which extends up to spacelike\nvirtualities of $0.7\\,{\\rm GeV}^2$ with fully quantified uncertainties, agrees\nwith previous lattice calculations but is significantly less steep than\nneutrino-deuterium scattering data suggests."
    },
    {
        "anchor": "Lattice computation of the nucleon scalar quark contents at the physical\n  point: We present a QCD calculation of the $u$, $d$ and $s$ scalar quark contents of\nnucleons based on $47$ lattice ensembles with $N_f = 2+1$ dynamical sea quarks,\n$5$ lattice spacings down to $0.054\\,\\text{fm}$, lattice sizes up to\n$6\\,\\text{fm}$ and pion masses down to $120\\,\\text{MeV}$. Using the\nFeynman-Hellmann theorem, we obtain $f^N_{ud} = 0.0405(40)(35)$ and $f^N_s =\n0.113(45)(40)$, which translates into $\\sigma_{\\pi N}=38(3)(3)\\,\\text{MeV}$,\n$\\sigma_{sN}=105(41)(37)\\,\\text{MeV}$ and $y_N=0.20(8)(8)$ for the sigma terms\nand the related ratio, where the first errors are statistical and the second\nare systematic. Using isospin relations, we also compute the individual up and\ndown quark contents of the proton and neutron (results in the main text).",
        "positive": "String-breaking in quenched QCD: We present results on a new operator for the investigation of string-breaking\neffects in quenched SU(2)-colour QCD. The ground state of a spatially-separated\nstatic-light meson-antimeson pair is a combination of a state with two distinct\nmesons, expected to dominate for large separations, and a state where the light\nquarks have annihilated, which contributes at short distances. The cross-over\nbetween these two regimes provides the string-breaking scale."
    },
    {
        "anchor": "Twisted supersymmetries in lattice ${\\cal N}=4$ super Yang-Mills theory: Recently it has been shown how a topologically twisted version of ${\\cal\nN}=4$ super Yang-Mills may be discretized in such a way as to preserve one\nscalar supersymmetry at nonzero lattice spacing. The remaining fifteen\nsupersymmetries are broken by terms of ${\\cal O}(a)$ where $a$ is the lattice\nspacing. One would like to know whether these remaining supersymmetries are\nregained in the continuum limit $a \\to 0$ and, if not, how much tuning of the\ncouplings in the lattice action is required. In this paper we derive the form\nof these additional twisted supersymmetries by combining a set of discrete\nR-symmetries of the continuum theory with the action of the scalar\nsupersymmetry. We then argue that restoration of rotational symmetry in the\ncontinuum limit of the lattice theory likely implies restoration of R-symmetry\nand hence should lead to an automatic enhancement to the full ${\\cal N}=4$\nsupersymmetry without further fine-tuning.",
        "positive": "Accelerating QDP++/Chroma on GPUs: Extensions to the C++ implementation of the QCD Data Parallel Interface are\nprovided enabling acceleration of expression evaluation on NVIDIA GPUs. Single\nexpressions are off-loaded to the device memory and execution domain leveraging\nthe Portable Expression Template Engine and using Just-in-Time compilation\ntechniques. Memory management is automated by a software implementation of a\ncache controlling the GPU's memory. Interoperability with existing Krylov space\nsolvers is demonstrated and special attention is paid on 'Chroma readiness'.\nNon-kernel routines in lattice QCD calculations typically not subject of\nhand-tuned optimisations are accelerated which can reduce the effects otherwise\nsuffered from Amdahl's Law."
    },
    {
        "anchor": "Investigations of QCD at non-zero isospin density: We investigate the QCD phase diagram as a function of isospin chemical\npotential at a fixed temperature by directly putting large numbers of \\pi^+s\ninto the system. Correlation functions of N \\pi^+s systems involves N!N!\ncontractions, and become extremely expensive when N is large. In order to\nalleviate this problem, a recursion relation of correlation functions has been\nderived in Ref. [1] that substantially reduces the number of independent\ncontractions needed and makes the study of many pions systems be possible. In\nthis proceeding this method is investigated numerically. We have also\nconstructed a new method that is even more efficient, enabling us to study\nsystems of up to 72 \\pi^+s.",
        "positive": "Does Conformal Quantum Field Theory Describe the Continuum Limits of 2D\n  Spin Models with Continuous Symmetry?: It is generally taken for granted that two-dimensional critical phenomena can\nbe fully classified by the well known two-dimensional (rational) conformal\nquantum field theories (CQFTs). In particular it is believed that in models\nwith a continuous symmetry characterized by a Lie group $G$ the continuum\ntheory enjoys an enhanced symmetry $G\\times G$ due to the decoupling of right\nand left movers. In this letter we review the conventional arguments leading to\nthis conclusion, point out two gaps and provide a conterexample. Nevertheless\nwe justify in the end the conventional conclusions by additional arguments."
    },
    {
        "anchor": "Perturbative renormalization factors and O(a^2) corrections for lattice\n  4-fermion operators with improved fermion/gluon actions: In this work we calculate the corrections to the amputated Green's functions\nof 4-fermion operators, in 1-loop Lattice Perturbation theory. One of the novel\naspects of our calculations is that they are carried out to O(a^2) (a: lattice\nspacing). We employ the Wilson/clover action for massless fermions (also\napplicable for the twisted mass action in the chiral limit) and a family of\nSymanzik improved actions for gluons. Our calculations have been carried out in\na general covariant gauge. Results have been obtained for several popular\nchoices of values for the Symanzik coefficients. While our Green's function\ncalculations regard any pointlike 4-fermion operators which do not mix with\nlower dimension ones, we pay particular attention to DF=2 operators, both\nParity Conserving and Parity Violating (F: flavour). We compute the\nperturbative renormalization constants for a complete basis of 4-fermion\noperators and we study their mixing pattern. For some of the actions considered\nhere, even O(a^0) results did not exist in the literature to date. The\ncorrection terms which we calculate are essential ingredients for minimizing\nthe lattice artifacts which are present in non-perturbative evaluations of\nrenormalization constants with the RI'-MOM method. Our perturbative results,\nfor the matrix elements of DF=2 operators and for the corresponding\nrenormalization matrices, depend on a large number of parameters: coupling\nconstant, number of colors, lattice spacing, external momentum, clover\nparameter, Symanzik coefficients, gauge parameter. To make these results most\neasily accessible, we have included them in the distribution package of this\npaper, as an ASCII file named: 4-fermi.m; the file is best perused as\nMathematica input. The main results of this work have been applied to improve\nnon-perturbative estimates of the B_K-parameter in N_F=2 twisted mass lattice\nQCD.",
        "positive": "Non-perturbative determination of anisotropy coefficients in lattice\n  gauge theories: We propose a new non-perturbative method to compute derivatives of gauge\ncoupling constants with respect to anisotropic lattice spacings (anisotropy\ncoefficients), which are required in an evaluation of thermodynamic quantities\nfrom numerical simulations on the lattice. Our method is based on a precise\nmeasurement of the finite temperature deconfining transition curve in the\nlattice coupling parameter space extended to anisotropic lattices by applying\nthe spectral density method. We test the method for the cases of SU(2) and\nSU(3) gauge theories at the deconfining transition point on lattices with the\nlattice size in the time direction $N_t=4$ -- 6. In both cases, there is a\nclear discrepancy between our results and perturbative values. A longstanding\nproblem, when one uses the perturbative anisotropy coefficients, is a\nnon-vanishing pressure gap at the deconfining transition point in the SU(3)\ngauge theory. Using our non-perturbative anisotropy coefficients, we find that\nthis problem is completely resolved: we obtain $\\Delta p/T^4 = 0.001(15)$ and\n$-0.003(17)$ on $N_t=4$ and 6 lattices, respectively."
    },
    {
        "anchor": "From the colour glass condensate to filamentation: Systematics of\n  classical Yang-Mills theory: The non-equilibrium early time evolution of an ultra-relativistic heavy ion\ncollision is often described by classical lattice Yang-Mills theory, starting\nfrom the colour glass condensate (CGC) effective theory with an anisotropic\nenergy momentum tensor as initial condition. In this work we investigate the\nsystematics associated with such studies and their dependence on various model\nparameters (IR, UV cutoffs and the amplitude of quantum fluctuations) which are\nnot yet fixed by experiment. We perform calculations for SU(2) and SU(3), both\nin a static box and in an expanding geometry. Generally, the dependence on\nmodel parameters is found to be much larger than that on technical parameters\nlike the number of colours, boundary conditions or the lattice spacing. In a\nstatic box, all setups lead to isotropisation through chromo-Weibel\ninstabilities, which is illustrated by the accompanying filamentation of the\nenergy density. However, the associated time scale depends strongly on the\nmodel parameters and in all cases is longer than the phenomenologically\nexpected one. In the expanding system, no isotropisation is observed for any\nparameter choice. We show how investigations at fixed initial energy density\ncan be used to better constrain some of the model parameters.",
        "positive": "The QCD Equation of State: Results for the equation of state in 2+1 flavor QCD at zero net baryon\ndensity using the Highly Improved Staggered Quark (HISQ) action by the HotQCD\ncollaboration are presented. The strange quark mass was tuned to its physical\nvalue and the light (up/down) quark masses fixed to $m_l = 0.05m_s$\ncorresponding to a pion mass of 160 MeV in the continuum limit. Lattices with\ntemporal extent $N_t=6$, 8, 10 and 12 were used. Since the cutoff effects for\n$N_t>6$ were observed to be small, reliable continuum extrapolations of the\nlattice data for the phenomenologically interesting temperatures range $130\n\\mathord{\\rm MeV} < T < 400 \\mathord{\\rm MeV}$ could be performed. We discuss\nstatistical and systematic errors and compare our results with other published\nworks."
    },
    {
        "anchor": "Scaling and the continuum limit of gluoN_c plasmas: We investigated the finite temperature (T) phase transition for SU(Nc) gauge\ntheory with Nc=4, 6, 8 and 10 at lattice spacing, a, of 1/(6T) or less. We\nfound that these theories have first order transitions at such small a. In many\ncases we were able to find the critical couplings with precision as good as a\nfew parts in 10^4. We also investigated the use of two-loop renormalization\ngroup equations in extrapolating the lattice results to the continuum, thus\nfixing the temperature scale in units of the phase transition temperature, Tc.\nWe found that when a \\le 1/(8Tc) the two-loop extrapolation was accurate to\nabout 1--2%. However, we found that trading Tc for the QCD scale, Lambda_MSbar,\nincreases uncertainties significantly, to the level of about 5--10%.",
        "positive": "Searching for the elusive critical endpoint at finite temperature and\n  isospin density: We consider 3-flavour lattice QCD with a finite chemical potential mu_I for\nisospin, close to the finite temperature transition from hadronic matter to a\nquark-gluon plasma. In this region one can argue that the position and probably\nthe nature of this transition mimic those at finite quark-number chemical\npotential mu. The quark mass is chosen to be close to the critical mass at zero\nchemical potentials. Since the Binder cumulants used to determine the nature of\nthis transition in HMD(R) simulations are very sensitive to the updating\nincrement dt, we have switched to the newer exact RHMC algorithm for our\nsimulations. Preliminary results indicate that there is no critical endpoint in\nthe small mu_I regime, at least none connected with the critical point at zero\nchemical potentials."
    },
    {
        "anchor": "Interplay between Deconfinement and Chiral Properties: We study interplay between confinement/deconfinement and chiral properties.\nWe derive some analytical relations of the Dirac modes with the confinement\nquantities, such as the Polyakov loop, its susceptibility and the string\ntension. For the confinement quantities, the low-lying Dirac eigenmodes are\nfound to give negligible contribution, while they are essential for chiral\nsymmetry breaking. This indicates no direct, one-to-one correspondence between\nconfinement/deconfinement and chiral properties in QCD. We also investigate the\nPolyakov loop in terms of the eigenmodes of the Wilson, the clover and the\ndomain-wall fermion kernels, respectively.",
        "positive": "The volume dependence of spectral weights and the pentaquark state: Before studying the pentaquark system we examine the spectral weights of the\ntwo lowest scattering states in the two-pion system in the isospin I=2 channel\non lattices of size $16^3\\times 32$, $24^3 \\times 32$ and $32^3 \\times 64$ at\n$\\beta=6.0$ in the quenched theory. We find that the spectral weights scale\nwith the volume for large time separations. Therefore very accurate data are\nnecessary in order that the spectral weights determined on different volumes\nyield a ratio that is precise enough to distinguish a scattering state from a\nsingle particle state. The pentaquark system is studied on the same lattices\nand scaling of the spectral weights of the low lying state is investigated. The\naccuracy of the results obtained for the scaling of spectral weights do not\nallow us to exclude a pentaquark resonance."
    },
    {
        "anchor": "The Kaon B-Parameter in Staggered Chiral Perturbation Theory: We calculate the kaon B-parameter, B_K, to next-to-leading order in staggered\nchiral perturbation theory. We extend the usual power counting to include the\neffects of using perturbative (rather than non-perturbative) matching factors.\nTaste breaking enters through the O(a^2) terms in the effective action, through\nmixing with higher-dimension operators, and through the truncation of matching\nfactors. These effects cause mixing with several additional operators,\ncomplicating the chiral and continuum extrapolations. We summarize the results\nhere; all details can be found in hep-lat/0507012.",
        "positive": "Low Energy Constants from the zero mode contribution to the\n  pseudo-scalar correlator: We apply different types of overlap operators in quenched QCD simulations to\ncompute the zero mode contribution to the pseudo-scalar correlator. In\nparticular we use the conventional Neuberger Dirac operator and the overlap\nhypercube Dirac operator. Confronting our data with the analytical predictions\nby Chiral Perturbation Theory we evaluate the pion decay constant and the\nparameter \\alpha of the quenched chiral Lagrangian."
    },
    {
        "anchor": "Scale setting for $N_f=3+1$ QCD: We present the scale setting for a new set of gauge configurations generated\nwith $N_f=3+1$ Wilson quarks with a non-perturbatively determined clover\ncoefficient in a massive O($a$) improvement scheme. The three light quarks are\ndegenerate, with the sum of their masses being equal to its value in nature and\nthe charm quark has its physical mass. We use open boundary conditions in time\ndirection to avoid the problem of topological freezing at small lattice\nspacings and twisted-mass reweighting for improved stability of the\nsimulations. The decoupling of charm at low energy allows us to set the scale\nby measuring the value of the low-energy quantity $t_0^\\star/a^2$, which is the\nflow scale $t_0$ at our mass point, and comparing it to an $N_f=2+1$ result in\nphysical units. We present the details of the algorithmic setup and tuning\nprocedure and give the bare parameters of ensembles with two lattice spacings\na=0.054 fm and a=0.043 fm. We discuss finite volume effects and lattice\nartifacts and present physical results for the charmonium spectrum. In\nparticular the hyperfine splitting between the $\\eta_c$ and $J/\\psi$ mesons\nagrees very well with its physical value.",
        "positive": "On the phase structure of twisted mass lattice QCD: The introduction of a chirally twisted mass term has been proposed as an\nattractive approach to O(a) improvement of Quantum Chromodynamics with Wilson\nfermions on a lattice. For numerical simulation projects it is important to\nknow the phase structure of the theory in the region of small quark masses. We\nstudy this question in the framework of chiral perturbation theory.\nGeneralizing the analysis of Sharpe and Singleton we find extensions of normal\nand Aoki phase scenarios and a possible new phase with spontaneous breakdown of\nchiral symmetry to a discrete $Z_2$."
    },
    {
        "anchor": "A Lattice Fermion Doublet With A Generalization Of The Ginsparg-Wilson\n  Relation: We present a new staggered discretization of the Dirac operator. In\ncomparison with standard staggered fermions, real and imaginary parts are\nlocated in different nodes. Doubling gives only a doublet of Dirac fermions\nwhich we propose to interpret as a physical (lepton or quark) doublet. Contrary\nto usual staggered fermions, we have no exact chiral symmetry but obtain a\ngeneralization of the Ginsparg-Wilson relation.",
        "positive": "An update on QCD+QED simulations with C* boundary conditions: We present two novelties in our analysis of fully dynamical QCD+QED ensembles\nwith C* boundary conditions. The first one is the explicit computation of the\nsign of the Pfaffian. We present an algorithm that provides a significant\nspeedup compared to traditional methods. The second one is a reweighting of the\nmass in the context of the RHMC. We have tested the techniques on both pure QCD\nand QCD+QED ensembles with pions at $m_{\\pi^\\pm}\\approx400$ MeV, a lattice\nspacing of $a\\approx0.05$ fm, a fine-structure constant of\n$\\alpha_{\\mathrm{R}}=0$ and $0.04$."
    },
    {
        "anchor": "Perfect lattice action for asymptotically free theories: There exist lattice actions which give cut--off independent physical\npredictions even on coarse grained lattices. Rotation symmetry is restored, the\nspectrum becomes exact and, in addition, the classical equations have scale\ninvariant instanton solutions. This perfect action can be made short ranged. It\ncan be determined by combining analytical calculations with numerical\nsimulations on small lattices. We illustrate the method and the benefits on the\n$d=2$ non--linear $\\sigma$--model.",
        "positive": "QCD on \u03b1-Clusters: It is shown that the 21264 Alpha processor can reach about 20% sustained\nefficiency for the inversion of the Wilson-Dirac operator. Since fast ethernet\nis not sufficient to get balancing between computation and communication on\nreasonable lattice- and system-sizes, an interconnection using Myrinet is\ndiscussed. We find a price/performance ratio comparable with state-of-the-art\nSIMD-systems for lattice QCD."
    },
    {
        "anchor": "QCD with domain wall quarks: We present lattice calculations in QCD using a variant of Kaplan fermions\nwhich retain the continuum SU(N)xSU(N) chiral symmetry on the lattice in the\nlimit of an infinite extra dimension. In particular, we show that the pion mass\nand the four quark matrix element related to K_0-K_0-bar mixing have the\nexpected behavior in the chiral limit, even on lattices with modest extent in\nthe extra dimension, e.g. N_s=10.",
        "positive": "The lattice ghost propagator in Landau gauge up to three loops using\n  Numerical Stochastic Perturbation Theory: We complete our high-accuracy studies of the lattice ghost propagator in\nLandau gauge in Numerical Stochastic Perturbation Theory up to three loops. We\npresent a systematic strategy which allows to extract with sufficient precision\nthe non-logarithmic parts of logarithmically divergent quantities as a function\nof the propagator momentum squared in the infinite-volume and $a\\to 0$ limits.\nWe find accurate coincidence with the one-loop result for the ghost self-energy\nknown from standard Lattice Perturbation Theory and improve our previous\nestimate for the two-loop constant contribution to the ghost self-energy in\nLandau gauge. Our results for the perturbative ghost propagator are compared\nwith Monte Carlo measurements of the ghost propagator performed by the Berlin\nHumboldt university group which has used the exponential relation between\npotentials and gauge links."
    },
    {
        "anchor": "The Heavy Hybrid Spectrum from NRQCD and the Born-Oppenheimer\n  Approximation: The spectrum of heavy-quark hybrids is studied in the leading\nBorn-Oppenheimer (LBO) approximation and using leading-order NRQCD simulations\nwith an improved gluon action on anisotropic lattices. The masses of four\nhybrid states are obtained from our simulations for lattice spacings 0.1 fm and\n0.2 fm and are compared to the LBO predictions obtained using\npreviously-determined glue-excited static potentials. The consistency of\nresults from the two approaches reveals a compelling physical picture for\nheavy-quark hybrid states.",
        "positive": "Exactly massless fermions on the lattice: The salient features of the Ginsparg-Wilson fermion in topologically\nnontrivial background gauge fields are outlined. The R-invariance of the zero\nmodes, the indices and the index theorem on a finite lattice are illustrated.\nThe role of R in converting the nonlocal D_c into a sequence of highly local D\nis demonstrated."
    },
    {
        "anchor": "Lyapunov Exponent of SU(3) Gauge Theory: The classical SU(3) gauge theory is shown to be deterministic chaotic. Its\nlargest Lyapunov exponent is dertermined, from which a short time scale of\nthermalization of a pure gluon system is estimated. The connection to gluon\ndamping rate is discussed.",
        "positive": "The Critical Hopping Parameter in O(a) improved Lattice QCD: We calculate the critical value of the hopping parameter, $\\kappa_c$, in O(a)\nimproved Lattice QCD, to two loops in perturbation theory. We employ the\nSheikholeslami-Wohlert (clover) improved action for Wilson fermions.\n  The quantity which we study is a typical case of a vacuum expectation value\nresulting in an additive renormalization; as such, it is characterized by a\npower (linear) divergence in the lattice spacing, and its calculation lies at\nthe limits of applicability of perturbation theory.\n  The dependence of our results on the number of colors $N$, the number of\nfermionic flavors $N_f$, and the clover parameter $c_{SW}$, is shown\nexplicitly. We compare our results to non perturbative evaluations of\n$\\kappa_c$ coming from Monte Carlo simulations."
    },
    {
        "anchor": "Onium Masses with Three Flavors of Dynamical Quarks: We have greatly extended an earlier calculation of the charmonium spectrum on\nthree flavor dynamical quark ensembles by using more recent ensembles generated\nby the MILC collaboration. The heavy quarks are treated using the Fermilab\nformulation. The charmonium state masses are in reasonable agreement with the\nobserved spectrum; however, some of the spin splittings may still be too small.",
        "positive": "Radiative Decay Width of $J/\u03c8\\to \u03b3\u03b7_{(2)}$ from $N_f=2$\n  Lattice QCD: The large radiative production rate for pseudoscalar mesons in the $J/\\psi$\nradiative decay remains elusive. We present the first lattice QCD calculation\nof partial decay width of $J/\\psi$ radiatively decaying into $\\eta_{(2)}$, the\n$\\mathrm{SU(2)}$ flavor singlet pseudoscalar meson, which confirms QCD\n$\\mathrm{U_A(1)}$ anomaly enhancement to the coupling of gluons with flavor\nsinglet pseudoscalar mesons. The lattice simulation is carried out using\n$N_f=2$ lattice QCD gauge configurations at the pion mass $m_{\\pi} \\approx 350$\nMeV. In particular, the distillation method has been utilized to calculate\nlight quark loops. The results are reported here with the mass $m_{\\eta_{(2)}}=\n718(8)$ MeV and the decay width $\\Gamma(J/\\psi\\to\\gamma \\eta_{(2)})=0.385(45)$\nkeV. By assuming the dominance of $\\mathrm{U_A(1)}$ anomaly and flavor\nsinglet-octet mixing angle $\\theta=-24.5^\\circ$, the production rates for the\nphysical $\\eta$ and $\\eta'$ in $J/\\psi$ radiative decay are predicted to be\n$1.15(14)\\times 10^{-3}$ and $4.49(53)\\times 10^{-3}$, respectively, which\nagree well with the experimental measurement data. Our study manifests the\npotential of lattice QCD studies on the light hadron production in $J/\\psi$\nradiative decays."
    },
    {
        "anchor": "Three-dimensional $O(N)$-invariant $\u03c6^4$ models at criticality for\n  $N\\ge 4$: We study the $O(N)$-invariant $\\phi^4$ model on the simple cubic lattice by\nusing Monte Carlo simulations. By using a finite size scaling analysis, we\nobtain accurate estimates for the critical exponents $\\nu$ and $\\eta$ for\n$N=4$, $5$, $6$, $8$, $10$, and $12$. We study the model for each $N$ for at\nleast three different values of the parameter $\\lambda$ to control leading\ncorrections to scaling. We compare our results with those obtained by other\ntheoretical methods.",
        "positive": "Spatially improved operators for excited hadrons on the lattice: We present a new approach for determining spatially optimized operators that\ncan be used for lattice spectroscopy of excited hadrons. Jacobi smeared quark\nsources with different widths are combined to construct hadron operators with\ndifferent spatial wave functions. We use the variational method to determine\nthose linear combinations of operators that have optimal overlap with ground\nand excited states. The details of the new approach are discussed and we\ndemonstrate the power of the method using examples from quenched baryon and\nmeson spectroscopy. In particular we study the Roper state and rho(1450) and\ndiscuss some physical implications of our tests."
    },
    {
        "anchor": "Numerical results for gauge theories near the conformal window: A novel strong interaction beyond the standard model could provide a\ndynamical explanation of electroweak symmetry breaking. Experimental results\nstrongly constrain properties of models that realise this mechanism. Whether\nthese constraints are obeyed by any strongly interacting quantum field theory\nis a non-perturbative problem that needs to be addressed by first-principle\ncalculations. Monte Carlo simulations of lattice regularised gauge theories is\na powerful tool that enables us to address this question. Recently various\nlattice investigations have appeared that have studied candidate models of\nstrongly interacting dynamics beyond the standard model. After a brief review\nof the main methods and of some recent results, we focus on the analysis of\nSU(2) gauge theory with one adjoint Dirac fermion flavour, which is shown to\nhave a near-conformal behaviour with an anomalous dimension of order one. The\nimplications of our findings are also discussed.",
        "positive": "Non-perturbative quark mass dependence in the heavy-light sector of\n  two-flavour QCD: We present preliminary results of the non-perturbative heavy quark mass\ndependence of heavy-light meson observables in the continuum limit of\nfinite-volume two-flavour lattice QCD. These observables, which are derived\nfrom heavy-light Schroedinger functional correlation functions and computed\nover a range of renormalization group invariant heavy quark masses from the\ncharm to beyond the bottom region, allow for a quantitative comparison with the\npredictions of HQET and are of practical relevance for solving renormalization\nproblems in HQET non-perturbatively by a matching to QCD in finite volume."
    },
    {
        "anchor": "Background field method and nonrelativistic QED matching: We discuss the resolution of an inconsistency between lattice background\nfield methods and nonrelativistic QED matching conditions. In particular, we\nshow that lack of on-shell conditions in lattice QCD with time-dependent\nbackground fields generally requires that certain operators related by\nequations of motion should be retained in an effective field theory to\ncorrectly describe the behavior of Green's functions. The coefficients of such\noperators in a nonrelativistic hadronic theory are determined by performing a\nrobust nonrelativistic expansion of QED for relativistic scalar and spin-half\nhadrons including nonminimal electromagnetic couplings. Provided that\nnonrelativistic QED is augmented with equation-of-motion operators, we find\nthat the background field method can be reconciled with the nonrelativistic QED\nmatching conditions without any inconsistency. We further investigate whether\nnonrelativistic QED can be employed in the analysis of lattice QCD correlation\nfunction in background fields, but we are confronted with difficulties.\nInstead, we argue that the most desirable approach is a hybrid one which relies\non a relativistic hadronic theory with operators chosen based on their\nrelevance in the nonrelativistic limit. Using this hybrid framework, we obtain\npractically useful forms of correlation functions for scalar and spin-half\nhadrons in uniform electric and magnetic fields.",
        "positive": "On the Quantum Geometry of String Theory: The IKKT or IIB matrix model has been proposed as a non-perturbative\ndefinition of type IIB superstring theories. It has the attractive feature that\nspace--time appears dynamically. It is possible that lower dimensional\nuniverses dominate the theory, therefore providing a dynamical solution to the\nreduction of space--time dimensionality. We summarize recent works that show\nthe central role of the phase of the fermion determinant in the possible\nrealization of such a scenario."
    },
    {
        "anchor": "Sign problem and phase quenching in finite-density QCD: models,\n  holography, and lattice: The effect of the complex phase of the fermion determinant is a key question\nrelated to the sign problem in finite-density QCD. Recently it has been shown\nthat ignoring the complex phase -- the phase quenching -- does not change\nphysics in a certain region of the phase diagram when a number of colors N_c is\nlarge. In this paper we study the effect of the phase quenching within the\nframeworks of effective models and holographic models. We show, in a unified\nmanner, that the phase quenching gives exact results for any fermionic\nobservables (e.g., chiral condensate) in the mean-field approximation and for\ngauge-invariant gluonic observables (e.g., Polyakov loop) to one-meson-loop\ncorrections beyond mean field. We also discuss implications for the lattice\nsimulations and confirm good quantitative agreement between our prediction and\nexisting lattice QCD results. Therefore the phase quenching provides rather\naccurate answer already at N_c=3 with small 1/N_c corrections which can be\ntaken into account by the phase reweighting.",
        "positive": "Search for the S=+1 pentaquarks in quenched lattice QCD: We study spin $\\frac12$ hadronic states in quenched lattice QCD to search for\na possible $S=+1$ pentaquark resonance. Our work is the first systematic\nlattice QCD study which properly carries out the following analyses: {\\it (1)\nthe careful extraction of the first two low energy states with very high\nstatistics and the variational method} and {\\it (2) the study of volume\ndependences of eigenenergies and spectral weights to distinguish resonance\nstates from scattering states}.\n  Simulations are carried out on $8^3\\times 24$, $10^3\\times 24$, $12^3\\times\n24$ and $16^3\\times 24$ lattices at $\\beta$=5.7 with the standard plaquette\ngauge action and the Wilson quark action. Our result indicates the existence of\na resonance state lying slightly above the NK threshold in\n$(I,J^P)=(0,\\frac12^-)$ channel in quenched QCD."
    },
    {
        "anchor": "More about vacuum structure of Linear Sigma Model: In the study of critical phenomena of QCD, a linear sigma model (LSM) is\noften analyzed as it shares many properties with QCD. Motivated by recent\narguments on effective restoration of the U_A(1) symmetry around the critical\ntemperature, the renormalization group flow of U(2)$\\otimes$U(2) LSM with a\nsmall violation of the U_A(1) symmetry is examined in the traditional epsilon\nexpansion in threedimensions. With a mass-dependent renormalization scheme, we\ninvestigate the attractive basin flowing into the O(4) LSM in the parameter\nspace and its dependence on the size of the U_A(1) breaking. Special emphasis\nis put on how the decoupling of the heavier degrees of freedom occur as\napproaching the O(4) LSM.",
        "positive": "Toward extracting scattering phase shift from integrated correlation\n  function: In present work, a relation that connects the integrated correlation function\nof a trapped two-particle system to infinite volume particles scattering phase\nshift is derived. It has the potential to provide an alternative approach for\nextracting two-particle scattering phase shift from integrated correlation\nfunction in lattice simulation at small Euclidean time region. Both (i)\nperturbation calculation of 1+1 dimensional lattice Euclidean field theory\nmodel of fermions interacting with a contact interaction and (ii) Monte Carlo\nsimulation of a 1D exactly solvable quantum mechanics model are carried out to\ntest the proposed relation. In contrast to conventional two-step approach of\nextracting energy levels from temporal correlation function in lattice\nsimulation at large Euclidean time first and then applying L\\\"uscher formula to\nconvert energy levels into scattering phase shifts, we show that the difference\nof integrated correlation functions between interacting and noninteracting\ntrapped systems converges rapidly to infinite volume limit that is given in\nterms of scattering phase shifts at small Euclidean time region."
    },
    {
        "anchor": "Are there Local Minima in the Magnetic Monopole Potential in Compact\n  QED?: We investigate the influence of the granularity of the lattice on the\npotential between monopoles. Using the flux definition of monopoles we\nintroduce their centers of mass and are able to realize continuous shifts of\nthe monopole positions. We find periodic deviations from the $1/r$-behavior of\nthe monopole-antimonopole potential leading to local extrema. We suppose that\nthese meta-stabilities may influence the order of the phase transition in\ncompact QED.",
        "positive": "Evidence for Asymptotic Safety from Lattice Quantum Gravity: We calculate the spectral dimension for nonperturbative quantum gravity\ndefined via Euclidean dynamical triangulations. We find that it runs from a\nvalue of ~3/2 at short distance to ~4 at large distance scales, similar to\nresults from causal dynamical triangulations. We argue that the short distance\nvalue of 3/2 for the spectral dimension may resolve the tension between\nasymptotic safety and the holographic principle."
    },
    {
        "anchor": "Quark number fluctuations at high temperatures: We calculate the second, fourth and sixth order quark number fluctuations in\nthe deconfined phase of 2+1 flavor QCD using lattices with temporal extent\nNt=4, 6, 8 and 12. We consider light, strange and charm quarks. We use p4\naction for valence quarks and gauge configurations generated with p4 action\nwith physical value of the strange quark mass and light quark mass mq=0.1ms\ngenerated by the RBC-Bielefeld collaboration. We observe that for all quark\nmasses the quark number fluctuations rapidly get close to the corresponding\nideal gas limits. We compare our results to predictions of a quasi-particle\nmodel and resummed high temperature perturbative calculations. We also\ninvestigate correlations among different flavor channels.",
        "positive": "Super-Instantons in Gauge Theories and Troubles with Perturbation Theory: In gauge theories with continuous groups there exist classical solutions\nwhose energy vanishes in the thermodynamic limit (in any dimension). The\nexistence of these super-instantons is intimately related to the fact that even\nat short distances perturbation theory can fail to produce unique results. This\nproblem arises only in non-Abelian models and only starting at O(1/beta^2)."
    },
    {
        "anchor": "Decomposition of the static potential in SU(3) gluodynamics: After fixing the Maximal Abelian gauge in SU(3) lattice gluodynamics we\ndecompose the nonabelian gauge field into the Abelian field created by Abelian\nmonopoles and the modified nonabelian field with monopoles removed. We then\ncalculate respective static potentials in the fundamental representation and\nshow that the sum of these potentials approximates the nonabelian static\npotential with good precision at all distances considered. Comparison with\nother ways of decomposition is made.",
        "positive": "S and P-wave heavy-light mesons in lattice NRQCD: The mass spectrum of S and P-wave mesons containing a single heavy quark is\ncomputed in the quenched approximation, using NRQCD up to third order in the\ninverse heavy quark mass expansion. Previous results found third order\ncontributions which are as large in magnitude as the total second order\ncontribution for the charmed S-wave spin splitting. The present work considers\nvariations such as anisotropic lattices, Landau link tadpole improvement, and a\nhighly-improved light quark action, and finds that the second order correction\nto the charmed S-wave spin splitting is about 20% of the leading order\ncontribution, while the third order correction is about 20%(10%) for\nD^*-D(D_s^*-D_s). Nonleading corrections are very small for the bottom meson\nspectrum, and are statistically insignificant for the P-wave charmed masses.\nThe relative orderings among P-wave charmed and bottom mesons, and the sizes of\nthe mass splittings, are discussed in light of experimental data and existing\ncalculations."
    },
    {
        "anchor": "Multipoint reweighting method and beta functions for the calculation of\n  QCD equation of state: We study a reweighting method aiming at numerical studies of QCD at finite\ndensity, in which the conventional Monte-Carlo method cannot be applied\ndirectly. One of the most important problems in the reweighting method is the\noverlap problem. To solve it, we propose to perform simulations at several\nsimulation points and combine their results in the data analyses. In this\nreport, we introduce this multipoint reweighting method and test if the method\nworks well by measuring histograms of physical quantities. Using this method,\nwe calculate the meson masses as continuous functions of the gauge coupling\nbeta and the hopping parameters kappa in QCD at zero density. We then determine\nlines of constant physics in the (beta, kappa) space and evaluate the\nderivatives of the lattice spacing with respect to beta and kappa along the\nlines of constant physics (inverse of the beta functions), which are needed in\na calculation of the equation of state.",
        "positive": "Minimal doubling and point splitting: Minimally-doubled chiral fermions have the unusual property of a single local\nfield creating two fermionic species. Spreading the field over hypercubes\nallows construction of combinations that isolate specific modes. Combining\nthese fields into bilinears produces meson fields of specific quantum numbers."
    },
    {
        "anchor": "Lattice QCD at Finite Temperature: I review recent progress in lattice QCD at finite temperature. Results on the\ntransition temperature will be summarized. Recent progress in understanding\nin-medium modifications of interquark forces and quarkonia spectral functions\nat finite temperatures is discussed.",
        "positive": "Dynamical Fermions with Fat Links: We present and test a new method for simulating dynamical fermions with fat\nlinks. Our construction is based on the introduction of auxiliary but dynamical\ngauge fields and works with any fermionic action and can be combined with any\nfermionic updating. In our simulation we use an over-relaxation step which\nmakes it effective. For four flavors of staggered fermions first results\nindicate that flavor symmetry at a lattice spacing a~0.2 fm is restored to a\nfew percent. With the standard action this amount of flavor symmetry\nrestoration is achieved at a~0.07 fm. We estimate that the overall\ncomputational cost is reduced by at least a factor 10."
    },
    {
        "anchor": "Detecting Lee-Yang/Fisher singularities by multi-point Pad\u00e8: The Bielefeld Parma Collaboration has in recent years put forward a method to\nprobe finite density QCD by the detection of Lee-Yang singularities. The\nlocation of the latter is obtained by multi-point Pad\\`e approximants, which\nare in turn calculated matching Taylor series results obtained from Monte Carlo\ncomputations at (a variety of values of) imaginary baryonic chemical potential.\nThe method has been successfully applied to probe the Roberge Weiss phase\ntransition and preliminary, interesting results are showing up in the vicinity\nof a possible QCD critical endpoint candidate. In this talk we will be\nconcerned with a couple of significant aspects in view of a more powerful\napplication of the method. First, we will discuss the possibility of detecting\nfinite size scaling of Lee-Yang/Fisher singularities in finite density\n(lattice) QCD. Second, we will briefly mention our attempts at detecting both\nsingularities in the complex chemical potential plane and singularities in the\ncomplex temperature plane. The former are obtained from rational approximations\nwhich are functions of the chemical potential at given values of the\ntemperature; the latter are obtained from rational approximations which are\nfunctions of the temperature at given values of the chemical potential.",
        "positive": "SU(3) sextet model with Wilson fermions: We present our final results for the SU(3) sextet model with the non-improved\nWilson fermion discretization. We find evidence for several phases of the\nlattice model, including a bulk phase with broken chiral symmetry. We study the\ntransition between the bulk and weak coupling phase which corresponds to a\nsignificant change in the qualitative behavior of spectral and scale setting\nobservables. In particular the t0 and w0 observables seem to diverge in the\nchiral limit in the weak coupling phase. We then focus on the study of spectral\nobservables in the chiral limit in the weak coupling phase at infinite volume.\nWe consider the masses and decay constants for the pseudoscalar and vector\nmesons, the mass of the axial vector meson and the spin-1/2 baryon as a\nfunction of the quark mass, while controlling finite volume effects. We then\ntest our data against both the IR conformal and the chirally broken hypotheses."
    },
    {
        "anchor": "Decuplet Baryon Structure from Lattice QCD: The electromagnetic properties of the SU(3)-flavor baryon decuplet are\nexamined within a lattice simulation of quenched QCD. Electric charge radii,\nmagnetic moments, and magnetic radii are extracted from the E0 and M1 form\nfactors. Preliminary results for the E2 and M3 moments are presented giving the\nfirst model independent insight to the shape of the quark distribution in the\nbaryon ground state. As in our octet baryon analysis, the lattice results give\nevidence of spin-dependent forces and mass effects in the electromagnetic\nproperties. The quark charge distribution radii indicate these effects act in\nopposing directions. Some baryon dependence of the effective quark magnetic\nmoments is seen. However, this dependence in decuplet baryons is more subtle\nthan that for octet baryons. Of particular interest are the lattice predictions\nfor the magnetic moments of $\\Omega^-$ and $\\Delta^{++}$ for which new recent\nexperimental measurements are available. The lattice prediction of the\n$\\Delta^{++}/p$ ratio appears larger than the experimental ratio, while the\nlattice prediction for the $\\Omega^-/p$ magnetic moment ratio is in good\nagreement with the experimental ratio.",
        "positive": "Leading isospin-breaking corrections to meson masses on the lattice: We present a study of the isospin-breaking (IB) corrections to pseudoscalar\n(PS) meson masses using the gauge configurations produced by the ETM\nCollaboration with $N_f=2+1+1$ dynamical quarks at three lattice spacings\nvarying from 0.089 to 0.062 fm. Our method is based on a combined expansion of\nthe path integral in powers of the small parameters $(\\widehat{m}_d -\n\\widehat{m}_u)/\\Lambda_{QCD}$ and $\\alpha_{em}$, where $\\widehat{m}_f$ is the\nrenormalized quark mass and $\\alpha_{em}$ the renormalized fine structure\nconstant. We obtain results for the pion, kaon and $D$-meson mass splitting;\nfor the Dashen's theorem violation parameters\n$\\epsilon_\\gamma(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$, $\\epsilon_{\\pi^0}$,\n$\\epsilon_{K^0}(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$; for the light quark\nmasses $(\\widehat{m}_d - \\widehat{m}_u)(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$,\n$(\\widehat{m}_u / \\widehat{m}_d)(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$; for\nthe flavour symmetry breaking parameters $R(\\overline{\\mathrm{MS}},\n2~\\mbox{GeV})$ and $Q(\\overline{\\mathrm{MS}}, 2~\\mbox{GeV})$ and for the strong\nIB effects on the kaon decay constants."
    },
    {
        "anchor": "Coulomb Confinement from the Yang-Mills Vacuum State in 2+1 Dimensions: The Coulomb-gauge ghost propagator, and the color-Coulomb potential, are\ncomputed in an ensemble of configurations derived from our recently proposed\nYang-Mills vacuum wavefunctional in 2+1 dimensions. The results are compared to\nthe corresponding values obtained by standard Monte Carlo simulations in three\nEuclidean dimensions. The agreement is quite striking for the Coulomb-gauge\nghost propagator. The color-Coulomb potential rises linearly at large\ndistances, but its determination suffers from rather large statistical\nfluctuations, due to configurations with very low values of $\\mu_0$, the lowest\neigenvalue of the Coulomb-gauge Faddeev-Popov operator. However, if one imposes\ncuts on the data, effectively leaving out configurations with very low $\\mu_0$,\nthe agreement of the potential in both sets of configurations is again\nsatisfactory, although the errorbars grow systematically as the cutoff is\neliminated.",
        "positive": "Performance of lattice QCD programs on CP-PACS: The CP-PACS is a massively parallel MIMD computer with the theoretical peak\nspeed of 614 GFLOPS which has been developed for computational physics\napplications at the University of Tsukuba, Japan. We report on the performance\nof the CP-PACS computer measured during recent production runs using our\nQuantum Chromodynamics code for the simulation of quarks and gluons in particle\nphysics. With the full 2048 processing nodes, our code shows a sustained speed\nof 237.5 GFLOPS for the heat-bath update of gluon variables, 264.6 GFLOPS for\nthe over-relaxation update, and 325.3 GFLOPS for quark matrix inversion with an\neven-odd preconditioned minimal residual algorithm."
    },
    {
        "anchor": "Charmonium properties in hot quenched lattice QCD: We study the properties of charmonium states at finite temperature in\nquenched QCD on large and fine isotropic lattices. We perform a detailed\nanalysis of charmonium correlation and spectral functions both below and above\n$T_c$. Our analysis suggests that both S wave states ($J/\\psi$ and $\\eta_c$)\nand P wave states ($\\chi_{c0}$ and $\\chi_{c1}$) disappear already at about $1.5\nT_c$. The charm diffusion coefficient is estimated through the Kubo formula and\nfound to be compatible with zero below $T_c$ and approximately $1/\\pi T$ at\n$1.5 T_c\\lesssim T\\lesssim 3 T_c$.",
        "positive": "Towards finite density QCD with Taylor expansions: We analyze general convergence properties of the Taylor expansion of\nobservables to finite chemical potential in the framework of an effective 2+1\nflavor Polyakov-quark-meson model. To compute the required higher order\ncoefficients a novel technique based on algorithmic differentiation has been\ndeveloped. Results for thermodynamic observables as well as the phase structure\nobtained through the series expansion up to 24th order are compared to the full\nmodel solution at finite chemical potential. The available higher order\ncoefficients also allow for resummations, e.g. Pade series, which improve the\nconvergence behavior. In view of our results we discuss the prospects for\nlocating the QCD phase boundary and a possible critical endpoint with the\nTaylor expansion method."
    },
    {
        "anchor": "Instability in the Molecular Dynamics Step of Hybrid Monte Carlo in\n  Dynamical Fermion Lattice QCD Simulations: We investigate instability and reversibility within Hybrid Monte Carlo\nsimulations using a non-perturbatively improved Wilson action. We demonstrate\nthe onset of instability as tolerance parameters and molecular dynamics step\nsizes are varied. We compare these findings with theoretical expectations and\npresent limits on simulation parameters within which a stable and reversible\nalgorithm is obtained for physically relevant simulations. Results of\noptimisation experiments with respect to tolerance prarameters are also\npresented.",
        "positive": "$\\mathcal{N}=1$ Super-Yang-Mills theory on the lattice with twisted mass\n  fermions: Super-Yang-Mills theory (SYM) is a central building block for supersymmetric\nextensions of the Standard Model of particle physics. Whereas the weakly\ncoupled subsector of the latter can be treated within a perturbative setting,\nthe strongly coupled subsector must be dealt with a non-perturbative approach.\nSuch an approach is provided by the lattice formulation. Unfortunately a\nlattice regularization breaks supersymmetry and consequently the mass\ndegeneracy within a supermultiplet. In this article we investigate the\nproperties of $\\mathcal{N}=1$ supersymmetric SU(3) Yang-Mills theory with a\nlattice Wilson Dirac operator with an additional parity mass, similar as in\ntwisted mass lattice QCD. We show that a special $45^\\circ$ twist effectively\nmoves the mass splitting of the chiral partners. Thus, at finite lattice\nspacing both chiral and supersymmetry are enhanced resulting in an improved\ncontinuum extrapolation. Furthermore, we show that for the non-interacting\ntheory at $45^\\circ$ twist discretization errors of order $\\mathcal{O}(a)$ are\nsuppressed, suggesting that the same happens for the interacting theory as\nwell. As an aside, we demonstrate that the DD$\\alpha$AMG multigrid algorithm\naccelerates the inversion of the Wilson Dirac operator considerably. On a\n$16^3\\times 32$ lattice, speed-up factors of up to 20 are reached if commonly\nused algorithms are replaced by the DD$\\alpha$AMG."
    },
    {
        "anchor": "Nature of the phase transition for finite temperature $N_{\\rm f}=3$ QCD\n  with nonperturbatively O($a$) improved Wilson fermions at $N_{\\rm t}=12$: We study the nature of the finite temperature phase transition for\nthree-flavor QCD. In particular we investigate the location of the critical\nendpoint along the three flavor symmetric line in the light quark mass region\nof the Columbia plot. In the study, the Iwasaki gauge action and the\nnonperturvatively O($a$) improved Wilson-Clover fermion action are employed. We\nnewly generate data at $N_{\\rm t}=12$ and set an upper bound of the critical\npseudoscalar meson mass in the continuum limit $m_{\\rm PS,E}\\lesssim 110$MeV.",
        "positive": "Three Topics in Renormalization and Improvement: This is an expanded version of lecture notes, delivered at the XCIII Les\nHouches Summer School (August 2009). Our aim is to present three very specific\ntopics: (i) The consequences of the loss of chiral symmetry in the Wilson\nlattice regularization of the fermionic action and its recovery in the\ncontinuum limit. The treatment of these arguments involves lattice Ward\nidentities. (ii) The definition and properties of mass independent\nrenormalization schemes, which are suitable for a non-perturbative computation\nof various operator renormalization constants. (iii) The modification of the\nWilson fermion action, by the introduction of a chirally twisted mass term\n(known as twisted mass QCD - tmQCD), which results to improved\n(re)normalization and scaling properties for physical quantities of interest."
    },
    {
        "anchor": "A Two-Parameter Recursion Formula For Scalar Field Theory: We present a two-parameter family of recursion formulas for scalar field\ntheory. The first parameter is the dimension $(D)$. The second parameter\n($\\zeta$) allows one to continuously extrapolate between Wilson's approximate\nrecursion formula and the recursion formula of Dyson's hierarchical model. We\nshow numerically that at fixed $D$, the critical exponent $\\gamma $ depends\ncontinuously on $\\zeta$. We suggest the use of the $\\zeta -$independence as a\nguide to construct improved recursion formulas.",
        "positive": "Massive photons: an infrared regularization scheme for lattice QCD+QED: Standard methods for including electromagnetic interactions in lattice\nquantum chromodynamics calculations result in power-law finite-volume\ncorrections to physical quantities. Removing these by extrapolation requires\ncostly computations at multiple volumes. We introduce a photon mass to\nalternatively regulate the infrared, and rely on effective field theory to\nremove its unphysical effects. Electromagnetic modifications to the hadron\nspectrum are reliably estimated with a precision and cost comparable to\nconventional approaches that utilize multiple larger volumes. A significant\noverall cost advantage emerges when accounting for ensemble generation. The\nproposed method may benefit lattice calculations involving multiple charged\nhadrons, as well as quantum many-body computations with long-range Coulomb\ninteractions."
    },
    {
        "anchor": "Properties of a New Class of Lattice Dirac Operators: A new class of lattice Dirac operators $D$ have been recently proposed on the\nbasis of the generalized Ginsparg-Wilson relation, $\\gamma_5(\\gamma_5 D) +\n(\\gamma_5 D)\\gamma_5 =2a^{2k+1}(\\gamma_5 D)^{2k+2}$, where $k$ is a\nnon-negative integer. We discuss the index theorem and locality properties for\nthis general class of lattice Dirac operators.",
        "positive": "Cooling study of Dirac sheets in SU(3) lattice gauge theory below T_c: Using a standard cooling method for SU(3) lattice gauge fields constant\nAbelian magnetic field configurations are extracted after dyon-antidyon\nconstituents forming metastable Q=0 configurations have annihilated. These\nso-called Dirac sheets, standard and non-standard ones, corresponding to the\ntwo U(1) subgroups of the SU(3) group, have been found to be stable if emerging\nfrom the confined phase, close to the deconfinement phase transition, with\nsufficiently nontrivial Polyakov loop values. On a finite lattice we find a\nnice agreement of the numerical observations with the analytic predictions\nconcerning the stability of Dirac sheets depending on the value of the Polyakov\nloop."
    },
    {
        "anchor": "Chiral forms and three-flavor operators for staggered baryons: In staggered QCD, many staggered baryons correspond to each physical state.\nTaste violations lift the continuum degeneracies of the baryons and introduce\nnonzero off-diagonal elements in the mass matrix. While presenting no problem\nof principle, these splittings and mixings complicate analyses of simulation\nresults. However, in special cases operators with good SU(3) quantum numbers\ncan be used to circumvent the splittings and mixings. I review what has been\nlearned from staggered chiral perturbation theory, outline a program of attack\nfor the amenable cases, and summarize the present status of work on the\nstaggered chiral forms and operators with good SU(3)xGTS quantum numbers.",
        "positive": "The lattice gradient flow at tree level: The cut-off effects of the lattice gradient flow -- often called Wilson flow\n-- are calculated on a periodic 4-torus at leading order in the gauge coupling.\nA large class of discretizations is considered which includes all frequently\nused cases in practice. It is shown how the results lead to a smoother\ncontinuum extrapolation for the beta-function of SU(3) gauge theory with N_f =\n4 flavors of fermions."
    },
    {
        "anchor": "Nucleon electromagnetic and axial form factors with N$_f$=2 twisted mass\n  fermions at the physical point: We present results for the nucleon electromagnetic and axial form factors\nusing an N$_f$=2 twisted mass fermion ensemble with pion mass of about 131 MeV.\nWe use multiple sink-source separations to identify excited state\ncontamination. Dipole masses for the momentum dependence of the form factors\nare extracted and compared to experiment, as is the nucleon magnetic moment and\ncharge and magnetic radii.",
        "positive": "The nucleon magnetic moment in the epsilon-regime of HBChPT: The nucleon magnetic moment is calculated in the epsilon-regime of Heavy\nBaryon Chiral Perturbation Theory to order epsilon^3, using the method of\ncollective variables to integrate nonperturbative pion zero modes.\nContributions containing multiple sources of zero modes enter, allowing for\ncharge-carrying zero mode pion fields that connect the sources. The result of\nthis calculation will allow for lattice QCD calculations involving nucleons to\nsystematically extract the leading low energy coefficients of Heavy Baryon\nChiral Perturbation Theory with electromagnetic interactions."
    },
    {
        "anchor": "Nature of chiral phase transition in two-flavor QCD: We investigate the nature of the chiral phase transition in the massless\ntwo-flavor QCD using the renormalization group improved gauge action and the\nWilson quark action on $32^3\\times 16$, $24^3\\times 12$, and $16^3\\times 8$\nlattices. We calculate the spacial and temporal propagators of the iso-triplet\nmesons in the pseudo-scalar ($PS$), scalar ($S$), vector ($V$) and axial-vector\n($AV$) channels on the lattice of three sizes. We first verify that the RG\nscaling is excellently satisfied for all cases. This is consistent with the\nclaim that the chiral phase transition is second order. Then we compare the\nspacial and temporal effective masses between the axial partners, i.e. $PS$ vs\n$S$ and $V$ vs $AV$, on each of the three size lattices. We find the effective\nmasses of all of six cases for the axial partners agree remarkably. This is\nconsistent with the claim that at least $Z_4$ subgroup of the $U_A(1)$ symmetry\nin addition to the $SU_A(2)$ symmetry is recovered at the chiral phase\ntransition point.",
        "positive": "On one-loop corrections to matching conditions of Lattice HQET including\n  1/m_b terms: HQET is an effective theory for QCD with N_f light quarks and a massive\nvalence quark if the mass of the latter is much bigger than Lambda_QCD. As any\neffective theory, HQET is predictive only when a set of parameters has been\ndetermined through a process called matching. The non-perturbative matching\nprocedure including 1/m_b terms, developped by the ALPHA collaboration,\nconsists of 19 carefully chosen observables which are precisely computable in\nlattice QCD as well as in lattice HQET. The matching conditions are then a set\nof 19 equations which relate the QCD and HQET values of these observables. We\npresent a study of one-loop corrections to two generic matching observables\ninvolving correlation function with an insertion of the A_0 operator. Our\nresults enable us to quantify the quality of the relevant observables in view\nof the envisaged non-perturbative implementation of this matching procedure."
    },
    {
        "anchor": "SMD-based numerical stochastic perturbation theory: The viability of a variant of numerical stochastic perturbation theory, where\nthe Langevin equation is replaced by the SMD algorithm, is examined. In\nparticular, the convergence of the process to a unique stationary state is\nrigorously established and the use of higher-order symplectic integration\nschemes is shown to be highly profitable in this context. For illustration, the\ngradient-flow coupling in finite volume with Schr\\\"odinger functional boundary\nconditions is computed to two-loop (i.e. NNL) order in the SU(3) gauge theory.\nThe scaling behaviour of the algorithm turns out to be rather favourable in\nthis case, which allows the computations to be driven close to the continuum\nlimit.",
        "positive": "Random Geometries and Real Space Renormalization Group: A method of ``blocking'' triangulations that rests on the self-similarity\nfeature of dynamically triangulated random manifolds is proposed. The method is\nused to define the renormalization group for random geometries. As an\nillustration, the idea is applied to pure euclidean quantum gravity in two\ndimensions. Generalisation to more complicated systems and to higher\ndimensionalities of space-time appears straightforward."
    },
    {
        "anchor": "QCD with light Wilson quarks on fine lattices (II): DD-HMC simulations\n  and data analysis: In this second report on our recent numerical simulations of two-flavour QCD,\nwe provide further technical details on the simulations and describe the\nmethods we used to extract the meson masses and decay constants from the\ngenerated ensembles of gauge fields. Among the topics covered are the choice of\nthe DD-HMC parameters, the issue of stability, autocorrelations and the\nstatistical error analysis. Extensive data tables are included as well as a\nshort discussion of the quark-mass dependence in partially quenched QCD,\nsupplementing the physics analysis that was presented in the first paper in\nthis series.",
        "positive": "Perfect Actions with Chemical Potential: We show how to include a chemical potential \\mu in perfect lattice actions.\nIt turns out that the standard procedure of multiplying the quark fields \\Psi,\n\\bar\\Psi at Euclidean time t by \\exp(\\pm \\mu t), respectively, is perfect. As\nan example, the case of free fermions with chemical potential is worked out\nexplicitly. Even after truncation, cut-off effects in the pressure and the\nbaryon density are small. Using a (quasi-)perfect action, numerical QCD\nsimulations for non-zero chemical potential become more powerful, because\ncoarse lattices are sufficient for extracting continuum physics."
    },
    {
        "anchor": "QCD thermodynamics with continuum extrapolated dynamical overlap\n  fermions: We study the finite temperature transition in QCD with two flavors of\ndynamical fermions at a pseudoscalar pion mass of about 350 MeV. We use\nlattices with temporal extent of $N_t$=8, 10 and 12. For the first time in the\nliterature a continuum limit is carried out for several observables with\ndynamical overlap fermions. These findings are compared with results obtained\nwithin the staggered fermion formalism at the same pion masses and extrapolated\nto the continuum limit. The presented results correspond to fixed topology and\nits effect is studied in the staggered case. Nice agreement is found between\nthe overlap and staggered results.",
        "positive": "A lattice NRQCD calculation of the $B^0-\\bar{B}^0$ mixing parameter B_B: We present a lattice calculation of the B meson B-parameter B_B using the\nNRQCD action. The heavy quark mass dependence is explicitly studied over a mass\nrange between m_b and 4m_b with the $O(1/m_Q)$ and $O(1/m_Q^2)$ actions. We\nfind that the ratios of lattice matrix elements $<O_N^{lat}>/<A_0^{lat}>^2$ and\n$<O_S^{lat}>/<A_0^{lat}>^2$, which contribute to B_B through mixing, have\nsignificant $1/m_Q$ dependence while that of the leading operator\n$<O_L^{lat}>/<A_0^{lat}>^2$ has little $1/m_Q$ effect. The combined result for\nB_B(m_b) has small but non-zero mass dependence, and the B_B(m_b) becomes\nsmaller by 10% with the 1/m_Q correction compared to the static result. Our\nresult in the quenched approximation at \\beta=5.9 is B_{B_d}(5 GeV) =\n0.75(3)(12), where the first error is statistical and the second is a\nsystematic uncertainty."
    },
    {
        "anchor": "Application of Multicanonical Multigrid Monte Carlo Method to the\n  Two-Dimensional $\u03c6^4$-Model: Autocorrelations and Interface Tension: We discuss the recently proposed multicanonical multigrid Monte Carlo method\nand apply it to the scalar $\\phi^4$-model on a square lattice. To investigate\nthe performance of the new algorithm at the field-driven first-order phase\ntransitions between the two ordered phases we carefully analyze the\nautocorrelations of the Monte Carlo process. Compared with standard\nmulticanonical simulations a real-time improvement of about one order of\nmagnitude is established. The interface tension between the two ordered phases\nis extracted from high-statistics histograms of the magnetization applying\nhistogram reweighting techniques.",
        "positive": "Twisted Mass Finite Volume Effects: We calculate finite volume effects on the pion masses and decay constant in\ntwisted mass lattice QCD (tmLQCD) at finite lattice spacing. We show that the\nlighter neutral pion in tmLQCD gives rise to finite volume effects that are\nexponentially enhanced when compared to those arising from the heavier charged\npions. We demonstrate that the recent two flavour twisted mass lattice data can\nbe better fitted when twisted mass effects in finite volume corrections are\ntaken into account."
    },
    {
        "anchor": "Noether supercurrent operator mixing from lattice perturbation theory: In this work we present perturbative results for the renormalization of the\nsupercurrent operator, $S_\\mu$, in ${\\cal N} =1$ Supersymmetric Yang-Mills\ntheory. At the quantum level, this operator mixes with both gauge invariant and\nnoninvariant operators, which have the same global transformation properties.\nIn total, there are 13 linearly independent mixing operators of the same and\nlower dimensionality. We determine, via lattice perturbation theory, the first\ntwo rows of the mixing matrix, which refer to the renormalization of $S_\\mu$,\nand of the gauge invariant mixing operator, $T_\\mu$. To extract these mixing\ncoefficients in the ${\\overline{\\rm MS}}$ renormalization scheme and at\none-loop order, we compute the relevant two-point and three-point Green's\nfunctions of $S_\\mu$ and $T_\\mu$ in two regularizations: dimensional and\nlattice. On the lattice, we employ the plaquette gluonic action and for the\ngluinos we use the fermionic Wilson action with clover improvement.",
        "positive": "The melting and abundance of open charm hadrons: Ratios of cumulants of conserved net charge fluctuations are sensitive to the\ndegrees of freedom that are carriers of the corresponding quantum numbers in\ndifferent phases of strong interaction matter. Using lattice QCD with 2+1\ndynamical flavors and quenched charm quarks we calculate second and fourth\norder cumulants of net charm fluctuations and their correlations with other\nconserved charges such as net baryon number, electric charge and strangeness.\nAnalyzing appropriate ratios of these cumulants we probe the nature of charmed\ndegrees of freedom in the vicinity of the QCD chiral crossover region. We show\nthat for temperatures above the chiral crossover transition temperature,\ncharmed degrees of freedom can no longer be described by an uncorrelated gas of\nhadrons. This suggests that the dissociation of open charm hadrons and the\nemergence of deconfined charm states sets in just near the chiral crossover\ntransition. Till the crossover region we compare these lattice QCD results with\ntwo hadron resonance gas models --including only the experimentally established\ncharmed resonances and also including additional states predicted by quark\nmodel and lattice QCD calculations. This comparison provides evidence for so\nfar unobserved charmed hadrons that contribute to the thermodynamics in the\ncrossover region."
    },
    {
        "anchor": "Dynamical solution of the strong CP problem within QCD ?: The strong CP problem is inseparably connected with the topology of gauge\nfields and the mechanism of color confinement, which requires nonperturbative\ntools to solve it. In this talk I present results of a recent lattice\ninvestigation of QCD with the $\\theta$ term in collaboration with Yoshifumi\nNakamura. The tool we are using to address the nonperturbative properties of\nthe theory is the gradient flow, which is a particular realization of momentum\nspace RG transformations. The novel result is that within QCD the vacuum angle\n$\\theta$ is renormalized, together with the strong coupling constant, and flows\nto $\\theta = 0$ in the infrared limit. This means that CP is conserved by the\nstrong interactions.",
        "positive": "Non-trivial Center Dominance in High Temperature QCD: We investigate the properties of quarks and gluons above the chiral phase\ntransition temperature $T_c,$ using the RG improved gauge action and the Wilson\nquark action with two degenerate quarks mainly on a $32^3\\times 16$ lattice. In\nthe one-loop perturbation theory, the thermal ensemble is dominated by the\ngauge configurations with effectively $Z(3)$ center twisted boundary\nconditions, making the thermal expectation value of the spatial Polyakov loop\ntake a non-trivial $Z(3)$ center. This is in agreement with our lattice\nsimulation of high temperature QCD. We further observe that the temporal\npropagator of massless quarks at extremely high temperature $\\beta=100.0 \\, (T\n\\simeq10^{58} T_c)$ remarkably agrees with the temporal propagator of free\nquarks with the $Z(3)$ twisted boundary condition for $t/L_t \\geq 0.2$, but\ndiffers from that with the $Z(3)$ trivial boundary condition. As we increase\nthe mass of quarks $m_q$, we find that the thermal ensemble continues to be\ndominated by the $Z(3)$ twisted gauge field configurations as long as $m_q \\le\n3.0 \\, T$ and above that the $Z(3)$ trivial configurations come in. The\ntransition is essentially identical to what we found in the departure from the\nconformal region in the zero-temperature many-flavor conformal QCD on a finite\nlattice by increasing the mass of quarks. We argue that the behavior is\nconsistent with the renormalization group analysis at finite temperature."
    },
    {
        "anchor": "Curing O(a) Errors in 3-D Lattice SU(2) x U(1) Higgs Theory: We show how to make O(a) corrections in the bare parameters of 3-D lattice\nSU(2) times U(1) Higgs theory which remove O(a) errors in the match between the\ninfrared behavior and the infrared behavior of the continuum theory. The\ncorrections substantially improve the convergence of lattice data to a small a\nlimit.",
        "positive": "The First Order Signal in Pure U(1) Gauge Theory May be Fake: We study the deconfinement phase transition of compact $U(1)$ pure lattice\ngauge theory with the Wilson action on {\\em closed topology} lattices. In\ncontrast to studies of compact QED on {\\em hypercubic lattices with periodic\nboundary conditions}, we find no metastability signal at the phase transition\non the lattices with the topology of a sphere. Thus the determination of the\norder of this phase transition has to be reconsidered. We argue that different\nproperties of closed monopole loops on these topological inequivalent lattices\nmight be responsible for the effect."
    },
    {
        "anchor": "A gauge-invariant object in non-Abelian gauge theory: We propose a nonlocal definition of a gauge-invariant object in terms of the\nWilson loop operator in a non--Abelian gauge theory. The trajectory is a closed\ncurve defined by an (untraced) Wilson loop which takes its value in the center\nof the color group. We show that definition shares basic features with the\ngauge-dependent 't Hooft construction of Abelian monopoles in Yang-Mills\ntheories. The chromoelectric components of the gluon field have a hedgehog-like\nbehavior in the vicinity of the object. This feature is dual to the structure\nof the 't Hooft-Polyakov monopoles which possesses a hedgehog in the magnetic\nsector. A relation to color confinement and lattice implementation of the\nproposed construction are discussed.",
        "positive": "Infrared Behaviour of SU(2) Gauge Theory with $N_f$ fundamental flavours: We review our recent results on the infrared behaviour of the SU(2) gauge\ntheory with $N_f$ massless fundamental flavour fermions. We have analyzed the\nrunning of the coupling in SU(2) gauge theories with six and eight fermionic\nflavours using the gradient flow step scaling method. From the running of the\ncoupling, we see a clear indication of an infrared stable fixed point in\ntheories with six and eight flavours. These results are confirmed by our mass\nspectrum study, where we varied the number of flavours from two to six. We also\ncompute the anomalous dimensions of mass and coupling."
    },
    {
        "anchor": "The nature of the Roberge-Weiss transition in $N_f=2$ QCD with Wilson\n  fermions: At imaginary values of the quark chemical potential $\\mu$, Quantum\nChromodynamics shows an interesting phase structure due to an exact center, or\nRoberge-Weiss (RW), symmetry. This can be used to constrain QCD at real $\\mu$,\nwhere the sign problem prevents Monte Carlo simulations of the lattice theory.\nIn previous studies of this region with staggered fermions it was found that\nthe RW endpoint, where the center transition changes from first-order to a\ncrossover, depends non-trivially on the quark mass: for high and low masses, it\nis a triple point connecting to the deconfinement and chiral transitions,\nrespectively, changing to a second-order endpoint for intermediate mass values.\nThese parameter regions are separated by tricritical points. Here we present a\nconfirmation of these findings using Wilson fermions on $N_\\tau=4$ lattices. In\naddition, our results provide a successful quantitative check for a heavy quark\neffective lattice theory at finite density.",
        "positive": "Coupling Yang-Mills with Causal Dynamical Triangulations: We discuss the algorithmic problem of minimal coupling gauge fields of the\nYang-Mills type to Quantum Gravity in the approach known as Causal Dynamical\nTriangulations (CDT) as a step towards studying, ultimately, systems of gravity\ncoupled with bosonic and fermionic matter. We first describe the algorithm for\ngeneral dimensions and gauge groups and then focus on the results obtained from\nsimulations of 2d CDT coupled to gauge fields with U{(1)} and SU{(2)} gauge\ngroups, where we studied both observables related to gravity and gauge fields,\nand compared them with analogous simulations in the static flat case."
    },
    {
        "anchor": "Aspects of gluon propagation in Landau gauge: spectral densities, and\n  mass scales at finite temperature: We discuss a method to extract the K\\\"all\\'en-Lehmann spectral density of a\nparticle (be it elementary or bound state) propagator and apply it to compute\ngluon spectral densities from lattice data. Furthermore, we also consider the\ninterpretation of the Landau-gauge gluon propagator at finite temperature as a\nmassive-type bosonic propagator.",
        "positive": "SU(N) polynomial integrals and some applications: We use the method of the Weingarten functions to evaluate SU(N) integrals of\nthe polynomial type. As an application we calculate various one-link integrals\nfor lattice gauge and spin SU(N) theories."
    },
    {
        "anchor": "A Lattice Simulation of the SU(2) Vacuum Structure: In this article we analyze the vacuum structure of pure SU(2) Yang-Mills\nusing non-perturbative techniques. Monte Carlo simulations are performed for\nthe lattice gauge theory with external sources to obtain the effective\npotential. Evidence from the lattice gauge theory indicating the presence of\nthe unstable mode in the effective potential is reported.",
        "positive": "Dualization of non-abelian lattice gauge theory with Abelian Color\n  Cycles (ACC): We discuss a new approach to strong coupling expansion and dual\nrepresentations for non-abelian lattice gauge theories. The Wilson gauge action\nis decomposed into a sum over \"abelian color cycles\" (ACC), which are loops\naround plaquettes visiting different colors at the corners. ACCs are complex\nnumbers and thus commute such that a dual representation of a non-abelian\ntheory can be obtained as in the abelian case. We apply the ACC approach to\nSU(2) and SU(3) lattice gauge theory and exactly rewrite the two partition sums\nin a strong coupling series where all gauge integrals are known in closed form."
    },
    {
        "anchor": "Maximum entropy analysis of hadron spectral functions and excited states\n  in quenched lattice QCD: Employing the maximum entropy method we extract the spectral functions from\nmeson correlators at four lattice spacings in quenched QCD with the Wilson\nquark action. We confirm that the masses and decay constants, obtained from the\nposition and the area of peaks, agree well with the results from the\nconventional exponential fit. For the first excited state, we obtain $m_{\\pi_1}\n= 660(590)$ MeV, $m_{\\rho_1} = 1540(570)$ MeV, and $f_{\\rho_1} = 0.085(36)$ in\nthe continuum limit.",
        "positive": "Deconstructing {\\\" U}nsal-Yaffe Reconfinement: In the UY reconfined phase on a lattice the thermal trace is over states\ntransforming in all $SU(N)/Z(N)$ irreducible representations as opposed to only\nover $SU(N)$ singlets in the standard formulation. As $N\\to\\infty$, on a finite\nlattice, the usual Hilbert space becomes orthogonal to the deformed one.\nConcerns about the extended UY proposal for large $N$ Eguchi-Kawai reduction\nare raised."
    },
    {
        "anchor": "Proton Spin Content From Lattice QCD: We calculate the form factor of the quark energy momentum tensor and thereby\nextract the quark orbital angular momentum of the nucleon. The calculation is\ndone on a quenched $16^3 \\times 24$ lattice at $\\beta = 6.0$ and with Wilson\nfermions at $\\kappa$ = 0.148, 0.152, 0.154 and 0.155. We calculate the\ndisconnected insertion stochastically which employs the $Z_2$ noise with an\nunbiased subtraction. This proves to be an efficient method of reduce the error\nfrom the noise. We find that the total quark contribution to the proton spin is\n$0.29 \\pm 0.07$. From this we deduce that the quark orbital angular momentum is\n$0.17 \\pm 0.08$ and predict the gluon spin to be $0.21 \\pm 0.07$, i.e. about\n40% of the proton spin is due to the glue.",
        "positive": "Hadron spectroscopy from canonical partition functions: A spectroscopic method for staggered fermions based on thermodynamical\nconsiderations is proposed. The canonical partition functions corresponding to\nthe different quark number sectors are expressed in the low temperature limit\nas polynomials of the eigenvalues of the reduced fermion matrix. Taking the\nzero temperature limit yields the masses of the lowest states. The method is\nsuccessfully applied to the Goldstone pion and both dynamical and quenched\nresults are presented showing good agreement with that of standard\nspectroscopy. Though in principle the method can be used to obtain the baryon\nand dibaryon masses, due to their high computational costs such calculations\nare practically unreachable."
    },
    {
        "anchor": "Scaling in the two-dimensional U(1)--Higgs model: We study the continuum limit of the $2D$ U(1)--Higgs model with variable\nscalar field length, which is qualitatively different from the fixed length\ncase. Our simulations concentrate on the scaling behaviour of the topological\nsusceptibility, and an instanton-induced confinement mechanism of fractional\ncharges is numerically confirmed.",
        "positive": "Topology and pion correlators -- a study in the N_f=2 Schwinger model: I readdress the issue whether the topological charge of the gauge background\nhas an influence on a hadronic observable. To this end pion correlators in the\nSchwinger model with 2 dynamical flavours are determined on subensembles with a\nfixed topological charge. It turns out that the answer depends on a specific\nfunction of the sea-quark mass and the box volume which is in close analogy to\nthe Leutwyler-Smilga parameter in full QCD."
    },
    {
        "anchor": "Aspects of determining fBs: scaling and power-law divergences: We present preliminary results for the decay constant of the Bs meson, fBs,\nat three values of beta=5.7, 6.0 and 6.2 using NRQCD and clover fermions for\nthe heavy and light quarks respectively. As a consistency check the decay\nconstant has also been extracted from the axial-vector current at finite\nmomentum. In addition, we discuss the cancellation of O(alpha/(aM0)) terms and\nthe remaining uncertainty in fBs from higher order divergences.",
        "positive": "Precision Control in Lattice Calculation of $x$-dependent Pion\n  Distribution Amplitude: We present a new Bjorken $x$-dependence analysis of a previous lattice\nquantum chromodynamics data for the pion distribution amplitude from MILC\nconfigurations with three lattice spacing $a=0.06,0.09, 0.12$~fm. A leading\nrenormalon resummation in renormalization as well as the perturbative matching\nkernel in the framework of large momentum expansion generates the power\naccuracy of the matching to the light-cone amplitude. Meanwhile, a small\nmomentum log resummation is implemented for both the quark momentum $xP_z$ and\nthe antiquark momentum $(1-x)P_z$ inside a meson of boost momentum $P_z$ up to\n1.72 GeV along the $z$ direction, allowing us to have more accurate\ndetermination of the $x$-dependence in the middle range. Finally, we use the\ncomplementarity between the short-distance factorization and the large momentum\nexpansion to constrain the endpoint regions $x\\sim 0, 1$, thus obtaining the\nfull-range $x$-dependence of the amplitude."
    },
    {
        "anchor": "Ordered vs Disordered: Correlation Lengths of 2D Potts Models at \u03b2_t: We performed Monte Carlo simulations of two-dimensional $q$-state Potts\nmodels with $q=10,15$, and $20$ and measured the spin-spin correlation function\nat the first-order transition point $\\beta_t$ in the disordered and ordered\nphase. Our results for the correlation length $\\xi_d(\\beta_t)$ in the\ndisordered phase are compatible with an analytic formula. Estimates of the\ncorrelation length $\\xi_o(\\beta_t)$ in the ordered phase yield strong numerical\nevidence that $R \\equiv \\xi_o(\\beta_t)/\\xi_d(\\beta_t) = 1$.",
        "positive": "Aoki Phases in the Lattice Gross-Neveu Model with Flavored Mass terms: We investigate the parity-broken phase structure for staggered and naive\nfermions in the Gross-Neveu model as a toy model of QCD. We consider a\ngeneralized staggered Gross-Neveu model including two types of four-point\ninteractions. We use generalized mass terms to split the doublers for both\nstaggered and naive fermions. The phase boundaries derived from the gap\nequations show that the mass splitting of tastes results in an Aoki phase both\nin the staggered and naive cases. We also discuss the continuum limit of these\nmodels and explore taking the chirally-symmetric limit by fine-tuning a mass\nparameter and two coupling constants. This supports the idea that in lattice\nQCD we can derive one- or two-flavor staggered fermions by tuning the mass\nparameter, which are likely to be less expensive than Wilson fermions in QCD\nsimulation."
    },
    {
        "anchor": "The author replies: I respond to the Bernard et al. comment on my letter ``Chiral anomalies and\nrooted staggered fermions.''",
        "positive": "COMBINING MCRG AND FOURIER ACCELERATED LANGEVIN ALGORITHM: We study the implementation of Monte Carlo renormalization group (MCRG) in\nmomentum space. This technique is most efficient when used in combination with\na Fourier accelerated Langevin algorithm. As a benchmark we calculate the\ncritical exponents $\\nu$ and $\\eta$ in the vicinity of both the gaussian and\nthe Wilson fixed point in $\\lambda \\phi^4_3$. The results are very competitive\nwith alternative analytical methods and require a moderate computational effort\nonly."
    },
    {
        "anchor": "Landau Gauge Fixing on GPUs and String Tension: We explore the performance of CUDA in performing Landau gauge fixing in\nLattice QCD, using the steepest descent method with Fourier acceleration. The\ncode performance was tested in a Tesla C2070, Fermi architecture. We also\npresent a study of the string tension at finite temperature in the confined\nphase. The string tension is extracted from the color averaged free energy and\nfrom the color singlet using Landau gauge fixing.",
        "positive": "Fermion RG blocking transformations and IR structure: We explore fermion RG block-spinning transformations on the lattice with the\naim of studying the IR structure of gauge theories and, in particular, the\nexistence of IR fixed points for varying fermion content. In the case of light\nfermions the main concern and difficulty is ensuring locality of any adopted\nblocking scheme. We discuss the problem of constructing a local blocked fermion\naction in the background of arbitrary gauge fields. We then discuss the\ncarrying out of accompanying gauge field blocking. In the presence of the\nblocked fermions implementation of MCRG is not straightforward. By adopting\njudicious approximations we arrive at an easily implementable approximate RG\nrecursion scheme that allows quick, inexpensive estimates of the location of\nconformal windows for various groups and fermion representations. We apply this\nscheme to locate the conformal windows in the case of SU(2) and SU(3) gauge\ngroups. Some of the reasons for the apparent efficacy of this and similar\ndecimation schemes are discussed."
    },
    {
        "anchor": "Charmonium resonances from 2+1 flavor CLS lattices: Many exotic charmonium resonances have been identified recently in\nexperiment, however their nature and properties are mostly unknown. Algorithmic\nand theoretical progress in lattice calculations has enabled reliable numerical\ninvestigation of the spectrum below the strong decay threshold, while the study\nof charmonium resonances remains an open challenge. The main difficulty to\novercome is the presence of many open decay channels which are coupled\ntogether, resulting in a complex finite volume quantization condition. We\nreport on our recent progress towards the determination of single-channel and\ncoupled-channel scattering matrices in the scalar and vector channels on CLS\nensembles. We also present an update concerning the study of the charmonium\nspectrum in moving frames.",
        "positive": "Reconstructed (charm) baryon methods at finite temperature on\n  anisotropic lattices: Reconstructed-correlator methods have been used to investigate thermal\neffects in mesonic correlation functions in a fit-independent manner. This\ntechnique has recently been extended to the baryonic sector. In this work\ndifferent ways of implementing this approach for baryon correlators are\nexamined. Using both real and synthetic data it is found that for heavy\nbaryons, such as the $\\Xi_{cc}(ccu)$ baryon, different choices are equivalent\nand that for the lighter nucleon the effect of different implementations is\nminimal. Further comparison to the so-called \"double ratio\" using the FASTSUM\nGeneration 2L thermal ensembles shows that reconstructed-correlator ratios and\ndouble ratios contain nearly identical quantitative information."
    },
    {
        "anchor": "Charmed baryon spectroscopy on the physical point in 2+1 flavor lattice\n  QCD: We investigate the charmed baryon mass spectrum using the relativistic heavy\nquark action on 2+1 flavor PACS-CS configurations previously generated on $32^3\n\\times 64$ lattice. The dynamical up-down and strange quark masses are set to\nthe physical values by using the technique of reweighting to shift the quark\nhopping parameters from the values employed in the configuration generation. At\nthe physical point, the lattice spacing equals $a^{-1}=2.194(10)$ GeV and the\nspatial extent $L=2.88(1)$ fm. Our results for the charmed baryon masses are\nconsistent with experiments except for $\\Xi_{cc}$, which has only weak\nexperimental evidence yet. We also predict mass values for other doubly and\ntriply charmed baryons.",
        "positive": "Flux tubes at finite temperature: The chromoelectric field generated by a static quark-antiquark pair, with its\npeculiar tube-like shape, can be nicely described, at zero temperature, within\nthe dual superconductor scenario for the QCD confining vacuum. In this work we\ninvestigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory,\nthe fate of chromoelectric flux tubes across the deconfinement transition. We\nfind that, as the temperature is increased towards and above the deconfinement\ntemperature $T_c$, the amplitude of the field inside the flux tube gets\nsmaller, while the shape of the flux tube does not vary appreciably across\ndeconfinement. This scenario with flux-tube \"evaporation\" above $T_c$ has no\ncorrespondence in ordinary (type-II) superconductivity, where instead the\ntransition to the phase with normal conductivity is characterized by a\ndivergent fattening of flux tubes as the transition temperature is approached\nfrom below. We present also some evidence about the existence of flux-tube\nstructures in the magnetic sector of the theory in the deconfined phase."
    },
    {
        "anchor": "One-loop renormalization factors and mixing coeffecients of bilinear\n  quark operators for improved gluon and quark actions: We calculate one-loop renormalization factors and mixing coefficients of\nbilinear quark operators for a class of gluon actions with six-link loops and\nO(a)-improved quark action. The calculation is carried out by evaluating\non-shell Green's functions of quarks and gluons in the standard perturbation\ntheory. We find a general trend that finite parts of one-loop coefficients are\nreduced approximately by a factor two for the renormalization-group improved\ngluon actions compared with the case of the standard plaquette gluon action.",
        "positive": "Analytic continuation in two-color QCD: new results on the critical line: We test the method of analytic continuation from imaginary to real chemical\npotential in two-color QCD, which is free from the sign problem. In particular,\nwe consider the analytic continuation of the critical line to real values of\nthe chemical potential."
    },
    {
        "anchor": "Heavy Flavours in Quark-Gluon Plasma: Recent progresses in lattice studies of heavy quark and quarkonium at\nnon-zero temperature are discussed. Formulating a tail of spectral functions as\na transport coefficient allows lattice determination of momentum diffusion\ncoefficient ($\\kappa$) for charm quark in the heavy quark mass limit and\nlattice determination of heavy quark/heavy anti-quark chemical equilibration\nrate in NRQCD. Quenched lattice study on a large volume gives $\\kappa/T^3 = 1.8\n\\cdots 3.4$ in the continuum limit. A recent study with $N_f = 2+1$\nconfigurations estimates the charmonium chemical equilibration rate\n$\\Gamma_{\\rm chem}$. At $T = 400$ MeV with $M \\sim 1.5$ GeV, $\\Gamma_{\\rm\nchem}^{-1} \\sim 150$ fm/c. Earlier results from the two studies (with different\nlattice setups and with different Bayesian priors) which calculate bottomonium\ncorrelators using NRQCD and employ Bayesian method to calculate spectral\nfunctions are summarized: $\\Upsilon (1S)$ survives upto $T \\sim 1.9 T_c$ and\nexcited states of $\\Upsilon$ are sequentially suppressed. The spectral\nfunctions of $\\chi_{b1}$ channel shows a Bayesian prior dependence of its\nthermal behavior: the $\\chi_{b1}$ spectral function with MEM prior shows\nmelting above $T_c$ but that with a new Bayesian prior hints survival of\n$\\chi_{b1}$ upto $\\sim 1.6 T_c$. Preliminary results from the efforts to\nunderstand the difference in the behavior of $\\chi_{b1}$ spectral function is\ngiven.",
        "positive": "Three-body scattering and quantization conditions from $S$ matrix\n  unitarity: Two methodologies have been presented in the literature which connect\nrelativistic three-particle scattering amplitudes with lattice QCD spectra --\nthe ``relativistic effective field theory'' approach and the ``finite-volume\nunitarity'' method. While both methods have been shown to be equivalent in\nvarious works, it has not been shown how to arrive at the relativistic\neffective field theory results directly from $S$ matrix unitarity. In this\nwork, we provide a simple proof of the relativistic effective field theory form\nof the scattering equations directly from unitarity. Motivated by the\nfinite-volume unitarity approach, we then postulate a set of quantization\nconditions which relate the finite-volume energy spectra to the $K$ matrices\nwhich drive the short-distance physics in the scattering equations, obtaining\nall previously known results for three identical particles. This work also\npresents new relations which provide a new pathway to generalize the results to\narbitrary systems."
    },
    {
        "anchor": "Lattice QCD and heavy ion collisions: a review of recent progress: In the last few years, numerical simulations of QCD on the lattice have\nreached a new level of accuracy. A wide range of thermodynamic quantities is\nnow available in the continuum limit and for physical quark masses. This allows\na comparison with measurements from heavy ion collisions for the first time.\nFurthermore, calculations of dynamical quantities are also becoming available.\nThe combined effort from first principles and experiment allows us to gain an\nunprecedented understanding of the properties of quark-gluon plasma. I will\nreview the state-of-the-art results from lattice simulations and connect them\nto the experimental information from RHIC and the LHC.",
        "positive": "Remarks on the quantum gravity interpretation of 4D dynamical\n  triangulation: We review some of the phenomenology in 4D dynamical triangulation and explore\nits interpretation in terms of a euclidean effective action of the continuum\nform $\\intx \\sqrt{g} [\\mu -\\frac{1}{16\\pi G} R + \\cdots]$."
    },
    {
        "anchor": "A lattice QCD study of pion-nucleon scattering in the Roper channel: We present a lattice QCD study of the puzzling positive-parity nucleon\nchannel, where the Roper resonance $N^*(1440)$ resides in experiment. The study\nis based on an ensemble of gauge configurations with $N_f=2+1$ Wilson-clover\nfermions with a pion mass of $156$ MeV and lattice size $L=2.9$ fm. We use\nseveral $qqq$ interpolating fields combined with $N\\pi$ and $N\\sigma$\ntwo-hadron operators in calculating the energy spectrum in the rest frame.\nCombining experimental $N\\pi$ phase shifts with elastic approximation and the\nL\\\"uscher formalism suggests in the spectrum an additional energy level near\nthe Roper mass $m_R=1.43$ GeV for our lattice. We do not observe any such\nadditional energy level, which implies that $N\\pi$ elastic scattering alone\ndoes not render a low-lying Roper resonance. The current status indicates that\nthe $N^*(1440)$ might arise as dynamically generated resonance from coupling to\nother channels, most notably the $N\\pi\\pi$.",
        "positive": "Phase Transition in Lattice Surface Systems with Gonihedric Action: We prove the existence of an ordered low temperature phase in a model of\nsoft-self-avoiding closed random surfaces on a cubic lattice by a suitable\nextension of Peierls contour method. The statistical weight of each surface\nconfiguration depends only on the mean extrinsic curvature and on an\ninteraction term arising when two surfaces touch each other along some contour.\nThe model was introduced by F.J. Wegner and G.K. Savvidy as a lattice version\nof the gonihedric string, which is an action for triangulated random surfaces."
    },
    {
        "anchor": "The Method of Recursive Counting: Can One Go Further?: After a short review of the Method of Recursive Counting we introduce a\ngeneral algebraic description of recursive lattice building. This provides a\nrigorous framework for discussion of method's limitations.",
        "positive": "Topological susceptibility in 2+1-flavor QCD with chiral fermions: We compute the topological susceptibility $\\chi_t$ of 2+1-flavor lattice QCD\nwith dynamical M\\\"obius domain-wall fermions, whose residual mass is kept at 1\nMeV or smaller. In our analysis, we focus on the fluctuation of the topological\ncharge density in a \"slab\" sub-volume of the simulated lattice, as proposed by\nBietenholz et al. The quark mass dependence of our results agrees well with the\nprediction of the chiral perturbation theory, from which the chiral condensate\nis extracted. Combining the results for the pion mass $M_\\pi$ and decay\nconstant $F_\\pi$, we obtain $\\chi_t$ = 0.227(02)(11)$M_\\pi^2 F_\\pi^2$ at the\nphysical point, where the first error is statistical and the second is\nsystematic."
    },
    {
        "anchor": "Large $N$ reduction in deformed Yang-Mills theories: We explore, at the nonperturbative level, the large $N$ equivalence between\nordinary $SU(N)$ Yang-Mills theory on $\\mathbb{R}^4$ and on $\\mathbb{R}^3\n\\times S^1$ with double-trace deformations. In particular, we compare the\nvalues of the $0^{++}$ glueball mass obtained in both sides of the equivalence.",
        "positive": "New ideas for g-2 on the lattice: Using iso-spin symmetry the quark-connected and disconnected contributions to\nthe hadronic vacuum polarisation in a theory with N_f=2 flavours can be\ndescribed as independent correlation functions, respectively. We show how this\nallows to use twisted boundary conditions for the connected contribution in\norder to improve the q^2-resolution in lattice QCD. Furthermore we derive an\nexact relation between the connected and the disconnected contributions at NLO\nin chiral perturbation theory. We discuss extensions to theories with more than\n2 dynamical flavours."
    },
    {
        "anchor": "Chiral extrapolations in 2+1 flavor domain wall fermion simulations: Simulations with 2+1 flavors of domain wall fermions provide us with the\nopportunity to compare the lattice data directly to the predictions of\ncontinuum chiral perturbation theory, up to corrections from the residual\nchiral symmetry breaking, $m_{res}$, and $O(a)$ lattice artefacts, which are\nrelatively small for domain wall fermions. We present preliminary results for\nthe pseudoscalar meson masses and decay constants from partially quenched\nsimulations and examine the next-to-leading order chiral extrapolations at\nsmall quark masses. The simulations were carried out on two lattice volumes :\n$16^3\\times 32$ and $24^3\\times 64$, with the lattice spacing fixed at about\n0.1 fm. The subtleties of the chiral fits are discussed. We also explore the\nroles of $m_{res}$ and $O(a)$ terms in the NLO chiral expansions and their\neffects on the chiral extrapolations for the pseudoscalar masses and decay\nconstants.",
        "positive": "Topology of dynamical lattice configurations including results from\n  dynamical overlap fermions: We investigate how the topological charge density in lattice QCD simulations\nis affected by violations of chiral symmetry caused by the fermion action. To\nthis end we compare lattice configurations generated with a number of different\nactions including first configurations generated with exact dynamical overlap\nquarks. We visualize the topological profiles after mild smearing. In the\ntopological charge correlator we measure the size of the positive core, which\nis known to shrink to zero extension in the continuum limit. To leading order\nwe find the core size to scale linearly with the lattice spacing with the same\ncoefficient for all actions, even including quenched simulations. In the\nsubleading term the different actions vary over a range of about 10 %. Our\nfindings suggest that non-chiral lattice actions at current lattice spacings do\nnot differ much for observables related to topology, both among themselves and\ncompared to overlap fermions."
    },
    {
        "anchor": "Singular values of the Dirac operator at nonzero density: At nonzero density the eigenvalues of the Dirac operator move into the\ncomplex plane, while its singular values remain real and nonnegative. In\nQCD-like theories, the singular-value spectrum carries information on the\ndiquark (or pionic) condensate. We have constructed low-energy effective\ntheories in different density regimes and derived a number of exact results for\nthe Dirac singular values, including Banks-Casher-type relations for the\ndiquark (or pionic) condensate, Smilga-Stern-type relations for the slope of\nthe singular-value density, and Leutwyler-Smilga-type sum rules for the inverse\nsingular values. We also present a rigorous index theorem for non-Hermitian\nDirac operators.",
        "positive": "Monte Carlo studies of dynamical compactification of extra dimensions in\n  a model of nonperturbative string theory: The IIB matrix model has been proposed as a non-perturbative definition of\nsuperstring theory. In this work, we study the Euclidean version of this model\nin which extra dimensions can be dynamically compactified if a scenario of\nspontaneously breaking the SO(10) rotational symmetry is realized. Monte Carlo\ncalculations of the Euclidean IIB matrix model suffer from a very strong\ncomplex action problem due to the large fluctuations of the complex phase of\nthe Pfaffian which appears after integrating out the fermions. We employ the\nfactorization method in order to achieve effective sampling. We report on\npreliminary results that can be compared with previous studies of the\nrotational symmetry breakdown using the Gaussian expansion method."
    },
    {
        "anchor": "Pion decay in magnetic fields: The leptonic decay of the charged pion in the presence of background magnetic\nfields is investigated using quenched Wilson fermions. It is demonstrated that\nthe magnetic field opens up a new channel for this decay. The magnetic\nfield-dependence of the decay constants for both the ordinary and the new\nchannel is determined. Using these inputs from QCD, we calculate the total\ndecay rate perturbatively.",
        "positive": "Lattice QCD estimates of thermal photon production from the QGP: Thermal photons produced in heavy-ion collision experiments are an important\nobservable for understanding quark-gluon plasma (QGP). The thermal photon rate\nfrom the QGP at a given temperature can be calculated from the spectral\nfunction of the vector current correlator. Extraction of the spectral function\nfrom the lattice correlator is known to be an ill-conditioned problem, as there\nis no unique solution for a spectral function for a given lattice correlator\nwith statistical errors. The vector current correlator, on the other hand,\nreceives a large ultraviolet contribution from the vacuum, which makes the\nextraction of the thermal photon rate difficult from this channel. We therefore\nconsider the difference between the transverse and longitudinal part of the\nspectral function, only capturing the thermal contribution to the current\ncorrelator, simplifying the reconstruction significantly. The lattice\ncorrelator is calculated for light quarks in quenched QCD at $T=470~$MeV ($\\sim\n1.5\\, T_c$), as well as in 2+1 flavor QCD at $T=220~$MeV ($\\sim 1.2 \\, T_{pc}$)\nwith $m_{\\pi}=320$ MeV. In order to quantify the non-perturbative effects, the\nlattice correlator is compared with the corresponding\n$\\text{NLO}+\\text{LPM}^{\\text{LO}}$ estimate of correlator. The reconstruction\nof the spectral function is performed in several different frameworks, ranging\nfrom physics-informed models of the spectral function to more general models in\nthe Backus-Gilbert method and Gaussian Process regression. We find that the\nresulting photon rates agree within errors."
    },
    {
        "anchor": "Partial-Global Stochastic Metropolis Update for Dynamical Smeared Link\n  Fermions: We performed dynamical simulations with HYP smeared staggered fermions using\nthe recently proposed partial-global stochastic Metropolis algorithm with\nfermion matrix reduction and determinant breakup improvements. In this paper we\ndiscuss our choice of the action parameters and study the autocorrelation time\nboth with four and two fermionic flavors at different quark mass values on\napproximately 10 fm^4 lattices. We find that the update is especially efficient\nwith two flavors making simulations on larger volumes feasible.",
        "positive": "Deformations of Boltzmann Distributions: Consider a one-parameter family of Boltzmann distributions $p_t(x) =\n\\tfrac{1}{Z_t}e^{-S_t(x)}$. This work studies the problem of sampling from\n$p_{t_0}$ by first sampling from $p_{t_1}$ and then applying a transformation\n$\\Psi_{t_1}^{t_0}$ so that the transformed samples follow $p_{t_0}$. We derive\nan equation relating $\\Psi$ and the corresponding family of unnormalized\nlog-likelihoods $S_t$. The utility of this idea is demonstrated on the $\\phi^4$\nlattice field theory by extending its defining action $S_0$ to a family of\nactions $S_t$ and finding a $\\tau$ such that normalizing flows perform better\nat learning the Boltzmann distribution $p_\\tau$ than at learning $p_0$."
    },
    {
        "anchor": "The scalar and tensor glueballs in the valence approximation: We evaluate the infinite volume, continuum limit of $0^{++}$ and $2^{++}$\nglueball masses in the valence approximation. We find $m_{0^{++}} = 1740 \\pm 71\n$~MeV and $m_{2^{++}} = 2359 \\pm 128 $~MeV, consistent with the interpretation\nof $f_0 ( 1710 )$ as the lightest scalar glueball.",
        "positive": "Derivative sources in lattice spectroscopy of excited light-quark mesons: We construct efficient interpolating fields for lattice spectroscopy of\nmesons by applying covariant derivatives on Jacobi smeared quark sources. These\ninterpolators are tested in a quenched calculation of excited mesons based on\nthe variational method. We present results for pseudoscalar, scalar, vector and\npseudovector mesons."
    },
    {
        "anchor": "Two and three loops computations of renormalization constants for\n  lattice QCD: Renormalization constants can be computed by means of Numerical Stochastic\nPerturbation Theory to two/three loops in lattice perturbation theory, both in\nthe quenched approximation and in the full (unquenched) theory. As a case of\nstudy we report on the computation of renormalization constants of the\npropagator for Wilson fermions. We present our unquenched (N_f=2) computations\nand compare the results with non perturbative determinations.",
        "positive": "Monopoles, confinement and deconfinement in lattice compact QED in\n  (2+1)D with external fields: Finite temperature compact electrodynamics in (2+1) dimensions is studied in\nthe presence of external electromagnetic fields. The deconfinement temperature\nis found to be insensitive to the external fields. This result corroborates our\nobservation that external fields create additional small--size magnetic dipoles\nfrom the vacuum which do not spoil the confining properties of the model at low\ntemperature. However, the Polyakov loop is not an order parameter of\nconfinement. It can vanish in deconfinement in the presence of external field.\nThis does not mean the restoration of confinement for certain external field\nfluxes. As a next step in the study of (2+1)D QED, the influence of monopoles\non the photon propagator is studied. First results are presented showing this\nconnection in the confining phase (without external field)."
    },
    {
        "anchor": "Higher-order hadronic-vacuum-polarization contribution to the muon g-2\n  from lattice QCD: We introduce a new method for calculating the ${\\rm O}(\\alpha^3)$\nhadronic-vacuum-polarization contribution to the muon anomalous magnetic moment\nfrom ${ab-initio}$ lattice QCD. We first derive expressions suitable for\ncomputing the higher-order contributions either from the renormalized vacuum\npolarization function $\\hat\\Pi(q^2)$, or directly from the lattice\nvector-current correlator in Euclidean space. We then demonstrate the approach\nusing previously-published results for the Taylor coefficients of\n$\\hat\\Pi(q^2)$ that were obtained on four-flavor QCD gauge-field configurations\nwith physical light-quark masses. We obtain $10^{10} a_\\mu^{\\rm HVP,HO} =\n-9.3(1.3)$, in agreement with, but with a larger uncertainty than,\ndeterminations from $e^+e^- \\to {\\rm hadrons}$ data plus dispersion relations.",
        "positive": "Hadronic Spectral Functions above the QCD Phase Transition: We extract the spectral functions in the scalar, pseudo-scalar, vector, and\naxial vector channels above the deconfinement phase transition temperature (Tc)\nusing the maximum entropy method (MEM). We use anisotropic lattices, 32^3 * 32,\n40, 54, 72, 80, and 96 (corresponding to T = 2.3 Tc --> 0.8 Tc), with the\nrenormalized anisotropy xi = 4.0 to have enough temporal data points to carry\nout the MEM analysis. Our result suggests that the spectral functions continue\nto possess non-trivial structures even above Tc and in addition that there is a\nqualitative change in the state of the deconfined matter between 1.5 Tc and 2\nTc."
    },
    {
        "anchor": "Effective action for the Abelian-Higgs model for a gauge-invariant\n  implementation on optical lattices: We present a gauge-invariant effective action for the Abelian-Higgs model in\n1+1 dimensions. It is constructed by integrating out the gauge field and then\nusing the hopping parameter expansion. The latter is tested with Monte Carlo\nsimulations for small values of the scalar self-coupling. In the opposite\nlimit, at infinitely large self-coupling, the Higgs mode is frozen and the\npartition function can be written in terms of local tensors and the tensor\nrenormalization group blocking can be applied. The numerical implementation\nrequires truncations and the time continuum limit of the blocked transfer\nmatrix can be obtained numerically. At zero gauge coupling and with a spin-1\ntruncation, the small volume energy spectrum is identical to the low energy\nspectrum of a two-species Bose-Hubbard model in the limit of large onsite\nrepulsion. The procedure is extended to finite gauge coupling and we derive a\nspin-1 approximation of the Hamiltonian which involves terms corresponding to\ntransitions among the two species in the Bose-Hubbard model. An optical lattice\nimplementation involving a ladder structure is proposed.",
        "positive": "Finite Temperature Phase Transition in SU(2) Lattice Gauge Theory with\n  Extended Action: We study the three dimensional fundamental-adjoint $SU(2)$ lattice gauge\ntheory at finite temperature by Monte Carlo simulations. We find that the\nfinite temperature deconfinement phase transition line joins the first order\nbulk phase transition line at its endpoint. Moreover, across the bulk\ntransition line, the Polyakov loop undergoes a discontinuous jump implying the\nexistence of both confining and deconfining phases on its two sides.\nImplications for universality and the nature of the confining-deconfining\ntransition are discussed."
    },
    {
        "anchor": "Constituent monopoles without gauge fixing: We discuss the recent construction of new exact finite temperature instanton\nsolutions with a non-trivial value of the Polyakov loop at infinity. They can\nbe shown, in a precise and gauge invariant way, to be formed by the\nsuperposition of n BPS monopoles for an SU(n) gauge group.",
        "positive": "Charged pion electric polarizability from four-point functions in\n  lattice QCD: Polarizabilities reveal valuable information on the internal structure of\nhadrons in terms of charge and current distributions. For neutral hadrons, the\nstandard approach is the background field method. But for a charged hadron, its\nacceleration under the applied field complicates the isolation of the\npolarization energy. In this work, we explore an alternative method based on\nfour-point functions in lattice QCD. The approach offers a transparent picture\non how polarizabilities arise from photon, quark, and gluon interactions. We\ncarry out a proof-of-concept simulation on the electric polarizability of a\ncharged pion, using quenched Wilson action on a $24^3\\times 48$ lattice at\n$\\beta=6.0$ with pion mass from 1100 to 370 MeV. We show in detail the\nevaluation and analysis of the four-point correlation functions and report\nresults on charge radius and electric polarizability. Our results from\nconnected diagrams suggest that charged pion $\\alpha_E$ is due to a\ncancellation between elastic and inelastic contributions. It would be\ninteresting to see how the cancellation plays out at smaller pion masses in\nfuture simulations."
    },
    {
        "anchor": "Melting of P wave bottomonium states in the quark-gluon plasma from\n  lattice NRQCD: We study the fate of P wave bottomonium states in the quark-gluon plasma,\nusing a spectral function analysis of euclidean lattice correlators. The\ncorrelators are obtained from lattice QCD simulations with two light quark\nflavours on highly anisotropic lattices, treating the bottom quark\nnonrelativistically. We find clear indications of melting immediately after the\ndeconfinement transition.",
        "positive": "Second Order Phase Transition in Anisotropic Lattice Gauge Theories with\n  Extra Dimensions: Field theories with extra dimensions live in a limbo. While their classical\nsolutions have been the subject of considerable study, their quantum aspects\nare difficult to control. A special class of such theories are anisotropic\ngauge theories. The anisotropy was originally introduced to localize chiral\nfermions. Their continuum limit is of practical interest and it will be shown\nthat the anisotropy of the gauge couplings plays a crucial role in opening the\nphase diagram of the theory to a new phase, that is separated from the others\nby a second order phase transition. The mechanism behind this is generic for a\ncertain class of models, that can be studied with lattice techniques. This\nleads to new perspectives for the study of quantum effects of extra dimensions."
    },
    {
        "anchor": "Imprint of chiral symmetry restoration on the Polyakov loop and the\n  heavy quark free energy: The Polyakov loop expectation value $\\langle P\\rangle$ is an order parameter\nof the deconfinement transition in the heavy quark mass regime, whereas its\nsensitivity to the deconfinement of light, dynamical quarks is not apparent.\nFrom the perspective of an effective Lagrangian in the vicinity of the chiral\ntransition, the Polyakov loop, $P$, is an energy-like observable, and $\\langle\nP\\rangle$ should hence scale like the energy density. Using $N_f=2+1$ HISQ\nconfigurations at finite lattice spacing, we show that near the chiral\ntransition temperature, the scaling behavior of $\\langle P\\rangle$ and the\nheavy quark free energy $F_q$ is consistent with energy-like observables in the\n3-$d$, O($N$) universality class. We extend this analysis to other Polyakov\nloop observables, including the response of the heavy quark free energy, $F_q$,\nto the baryon chemical potential, which is expected to scale like a specific\nheat.",
        "positive": "Chiral phase transition in (2 + 1)-flavor QCD: The chiral phase transition temperature $T_{c}^{0}$ is a fundamental quantity\nof QCD. To determine this quantity we have performed simulations of (2 +\n1)-flavor QCD using the Highly Improved Staggered Quarks (HISQ/tree) action on\n$N_{\\tau}=6, 8$ and 12 lattices with aspect ratios $N_{\\sigma}/N_{\\tau}$\nranging from 4 to 8. In our simulations the strange quark mass is fixed to its\nphysical value $m_{s}^{\\rm{phy}}$, and the values of two degenerate light quark\nmasses $m_{l}$ are varied from $m_{s}^{\\rm{phy}}/20$ to $m_{s}^{\\rm{phy}}/160$\nwhich correspond to a Goldstone pion mass $m_{\\pi}$ ranging from 160 MeV to 55\nMeV in the continuum limit. By investigating the light quark mass dependence\nand the volume dependence of various chiral observables, e.g. chiral\nsusceptibilities and Binder cumulants, no evidence for a first order phase\ntransition in our current quark mass window is found. Two estimators $T_{60}$\nand $T_{\\delta}$ are proposed to extract the chiral phase transition\ntemperature $T_{c}^{0}$ in the chiral and continuum limit and our current\nestimate for $T_{c}^{0}$ is $132_{-6}^{+3}$ MeV."
    },
    {
        "anchor": "Emergent phenomena from centre vortices in dynamical QCD: Quark confinement and dynamical chiral symmetry breaking are two of the most\nimportant emergent properties of the theory of quantum chromodynamics. We\nreview recent results studying centre vortices in SU(3) lattice gauge theory\nwith dynamical quarks. Through a vortex identification procedure,\nvortex-removed and vortex-only fields are obtained from the usual Monte Carlo\ngenerated gauge fields. Several comparisons between the untouched fields and\nthe vortex-modified fields support the notion that centre vortices are\nfundamental to both confinement and dynamical chiral symmetry breaking in full\nQCD.",
        "positive": "A massive momentum-subtraction scheme: A new renormalization scheme is defined for fermion bilinears in QCD at non\nvanishing quark masses. This new scheme, denoted RI/mSMOM, preserves the\nbenefits of the nonexceptional momenta introduced in the RI/SMOM scheme, and\nallows a definition of renormalized composite fields away from the chiral\nlimit. Some properties of the scheme are investigated by performing explicit\none-loop computation in dimensional regularization."
    },
    {
        "anchor": "The electroweak Hamiltonian in the gradient flow formalism: Over the last decade the gradient flow formalism has become an important tool\nfor lattice simulations of Quantum Chromodynamics. It offers remarkable\nrenormalization properties which pave the way for cross-fertilization between\nperturbative and lattice calculations. In this contribution we report on the\nconstruction of the flowed operator product expansion for the current-current\noperators of the electroweak Hamiltonian at NNLO QCD. This allows for simpler\ntransformations between lattice and perturbative schemes and might reduce the\nuncertainties of theoretical predictions for low-energy flavor observables.",
        "positive": "Series expansion of the quark determinant in the number of\n  quark-antiquark pairs: We propose a formulation of the QCD partition function which leads to a\nseries expansion of the quark determinant in any given baryonic sector. The\nr-th term gives the gauge-invariant contribution of the valence quarks plus r\nquark-antiquark pairs. This expansion can be used to investigate any baryonic\nsector, starting from the nucleon up to high baryonic densities."
    },
    {
        "anchor": "Partial Restoration of Flavor Symmetry for Chiral Staggered Fermions: At non-zero lattice spacing the flavor symmetry of staggered fermions is\nbroken to a discrete subgroup. We show that in the chiral limit the flavor\nsymmetry of the pion effective Lagrangian enlarges to an SO(4) subgroup of the\ncontinuum SU(4) symmetry. This provides an explanation for observed\ndegeneracies in the pion spectrum.",
        "positive": "Density-of-states: Although Monte Carlo calculations using Importance Sampling have matured into\nthe most widely employed method for determining first principle results in QCD,\nthey spectacularly fail for theories with a sign problem or for which certain\nrare configurations play an important role. Non-Markovian Random walks, based\nupon iterative refinements of the density-of-states, overcome such overlap\nproblems. I will review the Linear Logarithmic Relaxation (LLR) method and, in\nparticular, focus onto ergodicity and exponential error suppression.\nApplications include the high-state Potts model, SU(2) and SU(3) Yang-Mills\ntheories as well as a quantum field theory with a strong sign problem: QCD at\nfinite densities of heavy quarks."
    },
    {
        "anchor": "Lattice Gauge Fixing as Quenching and the Violation of Spectral\n  Positivity: Lattice Landau gauge and other related lattice gauge fixing schemes are known\nto violate spectral positivity. The most direct sign of the violation is the\nrise of the effective mass as a function of distance. The origin of this\nphenomenon lies in the quenched character of the auxiliary field $g$ used to\nimplement lattice gauge fixing, and is similar to quenched QCD in this respect.\nThis is best studied using the PJLZ formalism, leading to a class of covariant\ngauges similar to the one-parameter class of covariant gauges commonly used in\ncontinuum gauge theories. Soluble models are used to illustrate the origin of\nthe violation of spectral positivity. The phase diagram of the lattice theory,\nas a function of the gauge coupling $\\beta$ and the gauge-fixing parameter\n$\\alpha$, is similar to that of the unquenched theory, a Higgs model of a type\nfirst studied by Fradkin and Shenker. The gluon propagator is interpreted as\nyielding bound states in the confined phase, and a mixture of fundamental\nparticles in the Higgs phase, but lattice simulation shows the two phases are\nconnected. Gauge field propagators from the simulation of an SU(2) lattice\ngauge theory on a $20^4$ lattice are well described by a quenched mass-mixing\nmodel. The mass of the lightest state, which we interpret as the gluon mass,\nappears to be independent of $\\alpha$ for sufficiently large $\\alpha$.",
        "positive": "Analytic continuation from imaginary to real chemical potential in\n  two-color QCD: The method of analytic continuation from imaginary to real chemical potential\nis one of the most powerful tools to circumvent the sign problem in lattice\nQCD. Here we test this method in a theory, 2-color QCD, which is free from the\nsign problem. We find that the method gives reliable results, within\nappropriate ranges of the chemical potential, and that a considerable\nimprovement can be achieved if suitable functions are used to interpolate data\nwith imaginary chemical potential."
    },
    {
        "anchor": "SU(2) gauge theory with $N_f=24$ quarks at non-zero mass: We study SU(2) gauge field theory with $N_f=24$ quarks. The theory is\nasymptotically non-free and, at vanishing quark mass, governed by a Gaussian\nfixed point at long distances. On the other hand, at non-zero quark mass the\nquarks are expected to decouple at long distances and the system behaves like\nconfining pure gauge SU(2) theory. We study the mass spectrum of the theory as\nthe quark mass is varied and obtain scaling laws for meson masses and string\ntension. We also measure the evolution of the coupling constant at non-zero\nquark mass with gradient flow method. We observe unambiguously the decoupling\nof the quarks with the associated change of evolution of the coupling constant.",
        "positive": "A simple idea for Lattice QCD at finite density: We pursue the idea of adding the naive $\\mu N$ term, where $\\mu$ is the quark\nchemical potential and $N$ is the conserved quark number, to the lattice QCD\naction. While computations of higher order susceptibilities, required for\nestimating the location of the QCD critical point, need a lot fewer number of\nquark propagators at any order as a result, it has its problem. We discuss a\nsolution, and examine if it works."
    },
    {
        "anchor": "Lattice QCD Study of the Pentaquark Baryons: We study the spin $\\frac12$ hadronic state in quenched lattice QCD to search\nfor a possible $S=+1$ pentaquark resonance. Simulations are carried out on\n$8^3\\times 24$, $10^3\\times 24$, $12^3\\times 24$ and $16^3\\times 24$ lattices\nat $\\beta$=5.7 at the quenched level with the standard plaquette gauge action\nand Wilson quark action. We adopt two independent operators with I=0 and\n$J^P=\\frac12$ to construct a $2\\times 2$ correlation matrix. After the\ndiagonalization of the correlation matrix, we successfully obtain the energies\nof the ground-state and the 1st excited-state in this channel. The volume\ndependence of the energies suggests the existence of a possible resonance state\nslightly above the NK threshold in I=0 and $J^P=\\frac12^-$ channel.",
        "positive": "Is there still any Tc mystery in lattice QCD? Results with physical\n  masses in the continuum limit III: The present paper concludes our investigations on the QCD cross-over\ntransition temperatures with 2+1 staggered flavours and one-link stout\nimprovement. We extend our previous two studies [Phys. Lett. B643 (2006) 46,\nJHEP 0906:088 (2009)] by choosing even finer lattices ($N_t$=16) and we work\nagain with physical quark masses. The new results on this broad cross-over are\nin complete agreement with our earlier ones. We compare our findings with the\npublished results of the hotQCD collaboration. All these results are confronted\nwith the predictions of the Hadron Resonance Gas model and Chiral Perturbation\nTheory for temperatures below the transition region. Our results can be\nreproduced by using the physical spectrum in these analytic calculations. The\nfindings of the hotQCD collaboration can be recovered by using a distorted\nspectrum which takes into account lattice discretization artifacts and heavier\nthan physical quark masses. This analysis provides a simple explanation for the\nobserved discrepancy in the transition temperatures between our and the hotQCD\ncollaborations."
    },
    {
        "anchor": "Determination of Lee-Yang edge singularities in QCD by rational\n  approximations: We report updated results on the determination of Lee-Yang edge (LYE)\nsingularities in $N_f = 2+1$ QCD using highly improved staggered quarks (HISQ)\nwith physical masses on $N_\\tau = 4, 6, 8$ lattices. The singularity structure\nof QCD in the complex $\\mu_B$ plane is probed using conserved charges\ncalculated at imaginary $\\mu_B$. The location of the singularities is\ndetermined by studying the (uncancelled) poles of multi-point Pad\\'e\napproximants. We show that close to the Roberge-Weiss (RW) transition, the\nlocation of the LYE singularities scales according to the $3$-$d$ $Z(2)$\nuniversality class. By combining the new $N_\\tau = 6$ data with the $N_\\tau =\n4$ data from our previous analysis we extract a rough estimate for the RW\ntemperature in the continuum limit. We also discuss some preliminary results\nfor the singularities close to the chiral phase transition obtained from\nsimulations on $N_\\tau = 6, 8$ lattices.",
        "positive": "A Monte Carlo study of old, new and tadpole improved actions: Scaling of mass ratios in intermediate volumes, obtained with improved SU(2)\nlattice actions is tested against analytic results for the Wilson and continuum\naction. A new improved action is introduced by adding a 2X2 plaquette to the\nSymanzik action. Completing a square leads to a covariant propagator that\nsimplifies perturbative calculations. Data is presented on lattices of size\n4**3X128, with lattice spacings of approximately 0.02 and 0.12 fermi. For the\nlatter case no further improvement as compared to the tree-level action was\nobserved when including the Lepage-Mackenzie tadpole correction to the one-loop\nimproved Luscher-Weisz Symanzik action."
    },
    {
        "anchor": "Topological properties of minimally doubled fermions in two space-time\n  dimensions: The two-dimensional Schwinger model is used to explore how lattice fermion\noperators perceive the global topological charge $q \\in \\mathbb{Z}$ of a given\nbackground gauge field. We focus on Karsten-Wilczek and Borici-Creutz fermions,\nwhich are minimally doubled, and compare them to Wilson, Brillouin, naive,\nstaggered and Adams fermions. For each operator the eigenvalue spectrum in a\nbackground with $q \\neq 0$ is determined along with the chiralities of the\neigenmodes, and the spectral flow of the pertinent hermitean operator is worked\nout. We find that Karsten-Wilczek and Borici-Creutz fermions perceive the\nglobal topological charge $q$ in the same way as staggered and naive fermions\ndo.",
        "positive": "The Polyakov loop models in the large N limit: Correlation function and\n  screening masses: We explore the 't Hooft-Veneziano limit of the Polyakov loop models at finite\nbaryon chemical potential. Using methods developed by us earlier we calculate\nthe two- and $N$-point correlation functions of the Polyakov loops. This gives\na possibility to compute the various potentials in the confinement phase and to\nderive the screening masses outside the confinement region. In particular, we\nestablish the existence of complex masses and an oscillating decay of\ncorrelations in a certain range of parameters. Furthermore, it is shown that\nthe calculation of the $N$-point correlation function in the confinement phase\nreduces to the geometric median problem. This leads to a large $N$ analog of\nthe $Y$ law for the baryon potential."
    },
    {
        "anchor": "Progress in understanding confinement: A few aspects of the mechanism of confinement of color by monopole\ncondensation are reviewed.",
        "positive": "Exploring chiral dynamics with overlap fermions: This talk presents a lattice study of spontaneous chiral symmetry breaking\nperformed by the JLQCD and TWQCD collaborations with dynamical overlap\nfermions. Our lattice configurations are generated in a fixed topological\nsector. Since finite volume effects, partly due to the fixed global topology,\nare mainly induced by pion fields, the dependence on the lattice volume,\ntopological charge and quark masses can be analytically predicted using chiral\nperturbation theory (ChPT). We find a good agreement of Dirac operator spectrum\ncalculated on the lattice with the ChPT prediction including its finite size\nscalings, through which the chiral condensate is determined with good accuracy."
    },
    {
        "anchor": "On the influence of colour magnetic currents on the confining properties\n  of SU(3) lattice gauge theory: We modify the standard Wilson action of SU(3) lattice gauge theory by adding\nan extra term which suppresses colour magnetic currents. We present numerical\nresults of simulations at zero and finite temperature and show that colour\nmagnetic currents strongly influence the confining properties of SU(3) lattice\ngauge theory.",
        "positive": "Spectroscopy of $Sp(4)$ lattice gauge theory with $n_f=3$ antisymmetric\n  fermions: We perform numerical calculations of masses and decay constants of the\nlightest (flavoured) pseudoscalar, vector and axial vector mesons in the\n$Sp(4)$ lattice gauge theory with three Dirac fermions in the antisymmetric\nrepresentation. The corresponding continuum theory plays an important role in\ncertain ultra-violet complete realisations of composite Higgs, partial top\ncompositeness, and composite dark matter models. In addition, we measure the\nmasses of other flavoured mesons in spin-$0$ and $1$ channels, as well as the\nfirst excited state of the vector mesons. Using the gradient flow to set the\nscale, we carry out the continuum extrapolation and show preliminary results\nfor the meson spectrum of the theory."
    },
    {
        "anchor": "Symanzik improvement of the gradient flow in lattice gauge theories: We apply the Symanzik improvement programme to the 4+1-dimensional local\nre-formulation of the gradient flow in pure $SU(N)$ lattice gauge theories. We\nshow that the classical nature of the flow equation allows to eliminate all\ncutoff effects at $\\mathcal O(a^2)$ which originate either from the discretized\ngradient flow equation or from the gradient flow observable. All the remaining\n$\\mathcal O(a^2)$ effects can be understood in terms of local counterterms at\nthe zero flow time boundary. We classify these counterterms and provide a\ncomplete set as required for on-shell improvement. Compared to the\n4-dimensional pure gauge theory only a single additional counterterm is\nrequired, which corresponds to a modified initial condition for the flow\nequation. A consistency test in perturbation theory is passed and allows to\ndetermine all counterterm coefficients to lowest non-trivial order in the\ncoupling.",
        "positive": "Two-point functions of quenched lattice QCD in Numerical Stochastic\n  Perturbation Theory: We summarize the higher-loop perturbative computation of the ghost and gluon\npropagators in SU(3) Lattice Gauge Theory. Our final aim is to compare with\nresults from lattice simulations in order to expose the genuinely\nnon-perturbative content of the latter. By means of Numerical Stochastic\nPerturbation Theory we compute the ghost and gluon propagators in Landau gauge\nup to three and four loops. We present results in the infinite volume and $a\n\\to 0$ limits, based on a general fitting strategy."
    },
    {
        "anchor": "Lattice Chiral Symmetry in Fermionic Interacting Theories and the\n  Antifield Formalism: Recently we have discussed realization of an exact chiral symmetry in\ntheories with self-interacting fermions on the lattice, based upon an auxiliary\nfield method. In this paper we describe construction of the lattice chiral\nsymmetry and discuss its structure in more detail. The antifield formalism is\nused to make symmetry consideration more transparent. We show that the quantum\nmaster equation in the antifield formalism generates all the relevant\nWard-Takahashi identities including a Ginsparg-Wilson relation for interacting\ntheories. Solutions of the quantum master equation are obtained in a closed\nform, but the resulting actions are found to be singular. Canonical\ntransformations are used to obtain four types of regular actions. Two of them\nmay define consistent quantum theories. Their Yukawa couplings are the same as\nthose obtained by using the chiral decomposition in the free field algebra.\nInclusion of the complete set of the auxiliary fields is briefly discussed.",
        "positive": "Analytic Continuation in Two-color Finite Density QCD and Chiral Random\n  Matrix Model: Two-color finite density QCD is free from the sign problem, and it is thus\nregarded as a good model to check the validity of the analytic continuation\nmethod. We study the method in terms of the corresponding chiral random matrix\nmodel. It is found that at temperatures slightly higher than the pseudo\ncritical temperature, the ratio type of extrapolated function works well in\naccordance with the results of the Monte Carlo simulations."
    },
    {
        "anchor": "Nucleon, $\u0394$ and $\u03a9$ excited states in $N_f=2+1$ lattice QCD: The energies of the excited states of the Nucleon, $\\Delta$ and $\\Omega$ are\ncomputed in lattice QCD, using two light quarks and one strange quark on\nanisotropic lattices. The calculation is performed at three values of the light\nquark mass, corresponding to pion masses $m_{\\pi}$ = 392(4), 438(3) and 521(3)\nMeV. We employ the variational method with a large basis of interpolating\noperators enabling six energies in each irreducible representation of the\nlattice to be distinguished clearly. We compare our calculation with the\nlow-lying experimental spectrum, with which we find reasonable agreement in the\npattern of states. The need to include operators that couple to the expected\nmulti-hadron states in the spectrum is clearly identified.",
        "positive": "Strange Quark Physics on the Lattice: We present results for hadrons containing a strange quark in quenched lattice\nQCD. We calculate masses and decay constants using 60 gauge configurations with\nan O(a)-improved fermion action at beta = 6.2. Using the rho mass to set the\nscale, we find hadron masses within two to three standard deviations of\nexperiment. Direct comparison with experiment for decay constants is obscured\nby uncertainty in current renormalisations. Finally, we present preliminary\nresults on the semi-leptonic decay D->K. We find f_K^+(0)/Z_V = 0.75+5-4 and\nf_K^0(0)/Z_V = 0.74+4-4."
    },
    {
        "anchor": "Consistency checks for two-body finite-volume matrix elements: II.\n  Perturbative systems: Using the general formalism presented in Refs. [1,2], we study the\nfinite-volume effects for the $\\mathbf{2}+\\mathcal{J}\\to\\mathbf{2}$ matrix\nelement of an external current coupled to a two-particle state of identical\nscalars with perturbative interactions. Working in a finite cubic volume with\nperiodicity $L$, we derive a $1/L$ expansion of the matrix element through\n$\\mathcal O(1/L^5)$ and find that it is governed by two universal\ncurrent-dependent parameters, the scalar charge and the threshold two-particle\nform factor. We confirm the result through a numerical study of the general\nformalism and additionally through an independent perturbative calculation. We\nfurther demonstrate a consistency with the Feynman-Hellmann theorem, which can\nbe used to relate the $1/L$ expansions of the ground-state energy and matrix\nelement. The latter gives a simple insight into why the leading volume\ncorrections to the matrix element have the same scaling as those in the energy,\n$1/L^3$, in contradiction to earlier work, which found a $1/L^2$ contribution\nto the matrix element. We show here that such a term arises at intermediate\nstages in the perturbative calculation, but cancels in the final result.",
        "positive": "UV Suppression by Smearing and Screening Correlators: We investigate the mechanism of smearing in the APE, Stout, HYP and HEX\nschemes through their effect on glue and quark Fourier modes. Using this, we\nnon-perturbatively tune the smearing parameters to their optimum values.\nSmearing causes a super-linear improvement in taste symmetry breaking in the\nhigh temperature phase of QCD. We use optimal smearing in the high temperature\nphase and find close agreement of meson screening masses with weak coupling\npredictions."
    },
    {
        "anchor": "Topological Susceptibility to High Temperatures via Reweighting: We measure the topological susceptibility of quenched QCD on the lattice at\ntwo high temperatures. For this, we define topology with the help of gradient\nflow and mitigate the statistical problem of topology at high temperatures\nusing a reweighting technique. This allows us to enhance tunneling events\nbetween topological sectors and alleviate topological freezing. We quote\ncontinuum extrapolated results for the susceptibility at $2.5$ and\n$4.1~T_\\mathrm c$ that agree well with the existing literature. We conclude\nthat the method is feasible and can be extended to unquenched QCD with no\nconceptual problems.",
        "positive": "The Gluon Propagator on a Large Volume, at $\u03b2=6.0$: We present the results of a high statistics lattice study of the gluon\npropagator, in the Landau gauge, at $\\beta=6.0$. As suggested by previous\nstudies, we find that, in momentum space, the propagator is well described by\nthe expression $G(k^2)= \\Big[ M^2 + Z\\cdot k^2(k^2/\\Lambda^2)^\\eta\\Big]^{-1} $.\nBy comparing $G(k^2)$ on different volumes, we obtain a precise determination\nof the exponent $\\eta=0.532(12)$, and verify that $M^2$ does not vanish in the\ninfinite volume limit. The behaviour of $\\eta$ and $M^2$ in the continuum limit\nis not known, and can only be studied by increasing the value of $\\beta$."
    },
    {
        "anchor": "Chiral transition via the Banks-Casher relation: We investigate the properties of the finite-temperature QCD transition\ntowards the chiral limit using staggered quarks. Starting from the 2+1-flavor\nphysical point, the limit of massless quarks is approached along two different\ntrajectories in the Columbia-plot. Unlike in previous approaches, the chiral\ncondensate is determined via the Banks-Casher relation. The first results of\nour finite size scaling analysis are presented.",
        "positive": "Large Field Cutoffs in Lattice Gauge Theory: In pure gauge SU(3) near beta = 6, weak and strong coupling expansions break\ndown and the MC method seems to be the only practical alternative. We discuss\nthe possibility of using a modified version of perturbation theory which relies\non a large field cutoff and has been successfully applied to the double-well\npotential (Y. M., PRL 88 141601). Generically, in the case of scalar field\ntheory, the weak coupling expansion is unable to reproduce the exponential\nsuppression of the large field configurations. This problem can be solved by\nintroducing a large field cutoff. The value of this cutoff can be chosen to\nreduce the discrepancy with the original problem. This optimization can be\napproximately performed using the strong coupling expansion and bridges the gap\nbetween the two expansions. We report recent attempts to extend this procedure\nfor SU(3) gauge theory on the lattice. We compare gauge invariant and gauge\ndependent (in the Landau gauge) criteria to sort the configurations into\n``large-field'' and ``small-field'' configurations. %We discuss the effects of\ndiscarding the large field configurations. We discuss the convergence of\nlattice perturbation theory and the way it can be modified in order to obtain\nresults similar to the scalar case."
    },
    {
        "anchor": "D-branes and Topological Charge in QCD: The recently observed long-range coherent structure of topological charge\nfluctuations in QCD is compared with theoretical expectations based on the\nAdS/CFT brane construction of nonsupersymmetric gauge theory by Witten. Similar\nobservations of coherent topologicalcharge structure in 2D $CP^{N-1}$ sigma\nmodels are interpreted in terms of Wilson lines representing world lines of\nscreened electric charges. The analogy between 2D U(1) and 4D Yang-Mills theory\nleads to the interpretation of the observed coherent sheets of topological\ncharge in QCD as screened ``Wilson bags'' first suggested by Luscher. The\nduality between the Wilson bag surface and a wrapped 6-brane in IIA string\ntheory is discussed. The complete screening of the force between bag surfaces\nfor integer values of the bag charge $\\theta/2\\pi$ corresponds to the\nobservation by Polchinski that the net force between d-branes from closed\nstring exchange vanishes for quantized values of Ramond-Ramond charge.",
        "positive": "SU(3) gauge theory with 12 flavours in a twisted box: We present preliminary result for the step-scaling study of the coupling\nconstant with the Yang-Mills gradient flow, in the twelve-favour SU(3) gauge\ntheory. In this work, the lattice simulation is performed using unimproved\nstaggered fermions and the Wilson plaquette gauge action, from which the\ngradient flow is also implemented. Imposing twisted boundary condition a'la\nt'Hooft and Parisi, our calculation is performed at zero fermion mass. The\nrenormalised coupling constant is extracted via the computation of the energy\ndensity. In order to examine the reliability of the continuum extrapolation, we\ninvestigate this coupling constant using two different lattice discretisations.\nOur result shows that in order to control the systematic effects in the\ncontinuum extrapolation, it is necessary to implement a large enough\ngradient-flow time. In the current calculation, the gauge-field averaging\nradius corresponding to the flow time has to be as large as 40% of the lattice\nsize."
    },
    {
        "anchor": "Block Spin Effective Action for 4d SU(2) Finite Temperature Lattice\n  Gauge Theory: The Svetitsky-Yaffe conjecture for finite temperature 4d SU(2) lattice gauge\ntheory is confirmed by observing matching of block spin effective actions of\nthe gauge model with those of the 3d Ising model. The effective action for the\ngauge model is defined by blocking the signs of the Polyakov loops with the\nmajority rule. To compute it numerically, we apply a variant of the IMCRG\nmethod of Gupta and Cordery.",
        "positive": "Recent progress in the effective string theory description of LGTs: In presence of a static pair of sources, the spectrum of low-lying states of\nany confining gauge theory in D space-time dimensions is described, at large\nsource separations, by an effective string theory. Recently two important\nadvances improved our understanding of this effective theory. First, it was\nrealized that the form of the effective action is strongly constrained by the\nrequirement of the Lorentz invariance of the gauge theory, which is\nspontaneously broken by the formation of a long confining flux tube in the\nvacuum. This constraint is strong enough to fix uniquely the first few\nsubleading terms of the action. Second, it has been realized that the first of\nthese allowed terms - a quartic polynomial in the field derivatives - is\nexactly the composite field $T\\bar{T}$, built with the chiral components, $T$\nand $\\bar{T}$, of the energy-momentum tensor of the 2d QFT describing the\ninfrared limit of the effective string. This irrelevant perturbation is quantum\nintegrable and yields, through the thermodynamic Bethe Ansatz (TBA), the energy\nlevels of the string which exactly coincide with the Nambu-Goto spectrum. In\nthis talk we first review the general implications of these two results and\nthen, as a test of the power of these methods, use them to construct the first\nfew boundary corrections to the effective string action."
    },
    {
        "anchor": "A High Statistics Study of Flavour-Singlet Mesons with Staggered\n  Fermions: We present some early results from a high statistics study of the scalar and\npseudoscalar singlet sectors of lattice QCD using 2+1 flavours of Asqtad\nimproved staggered fermions. The use of the Asqtad action has allowed us to\ngenerate an unprecedented number of configurations at 2 lattice spacings which\non completion we hope will give us a significantly improved view of both the\nscalar and pseudoscalar singlet sectors.",
        "positive": "Studies on the Chiral Order Parameter in the Schwinger Model: Based on an analytical technique using a unitary transformation and the\nvariational method, we study the chiral order parameter in the Schwinger model\nin the lattice formalism with Kogut-Susskind fermions. The fermion condensate\n$\\langle {\\bar\\Psi} \\Psi \\rangle $ for any coupling constant and fermion mass\nare calculated. Chiral symmetry is shown to be broken in the massless limit and\ngood scaling behavior is obtained."
    },
    {
        "anchor": "QCD phase diagram for nonzero isospin-asymmetry: The QCD phase diagram is studied in the presence of an isospin asymmetry\nusing continuum extrapolated staggered quarks with physical masses. In\nparticular, we investigate the phase boundary between the normal and the pion\ncondensation phases and the chiral/deconfinement transition. The simulations\nare performed with a small explicit breaking parameter in order to avoid the\naccumulation of zero modes and thereby stabilize the algorithm. The limit of\nvanishing explicit breaking is obtained by means of an extrapolation, which is\nfacilitated by a novel improvement program employing the singular value\nrepresentation of the Dirac operator. Our findings indicate that no pion\ncondensation takes place above $T\\approx 160$ MeV and also suggest that the\ndeconfinement crossover continuously connects to the BEC-BCS crossover at high\nisospin asymmetries. The results may be directly compared to effective theories\nand model approaches to QCD.",
        "positive": "Localization properties of lattice fermions with plaquette and improved\n  gauge actions: We determine the location $\\lambda_c$ of the mobility edge in the spectrum of\nthe hermitian Wilson operator in pure-gauge ensembles with plaquette, Iwasaki,\nand DBW2 gauge actions. The results allow mapping a portion of the (quenched)\nAoki phase diagram. We use Green function techniques to study the localized and\nextended modes. Where $\\lambda_c>0$ we characterize the localized modes in\nterms of an average support length and an average localization length, the\nlatter determined from the asymptotic decay rate of the mode density. We argue\nthat, since the overlap operator is commonly constructed from the Wilson\noperator, its range is set by the value of $\\lambda_c^{-1}$ for the Wilson\noperator. It follows from our numerical results that overlap simulations\ncarried out with a cutoff of 1 GeV, even with improved gauge actions, could be\nafflicted by unphysical degrees of freedom as light as 250 MeV."
    },
    {
        "anchor": "Strategies for an accurate determination of the X(3872) energy from QCD\n  lattice simulations: We develop a method to determine accurately the binding energy of the X(3872)\nfrom lattice data for the $D \\bar D^*$ interaction. We show that, because of\nthe small difference between the neutral and charged components of the X(3872),\nit is necessary to differentiate them in the energy levels of the lattice\nspectrum if one wishes to have a precise determination of the the binding\nenergy of the X(3872). The analysis of the data requires the use of coupled\nchannels. Depending on the number of levels available and the size of the box\nwe determine the precision needed in the lattice energies to finally obtain a\ndesired accuracy in the binding energy.",
        "positive": "Loop States in Lattice Gauge Theories: We solve the Gauss law as well as the corresponding Mandelstam constraints of\n(d+1) dimensional SU(2) lattice gauge theory in terms of harmonic oscillator\nprepotentials. This enables us to explicitly construct a complete orthonormal\nand manifestly gauge invariant basis in the physical Hilbert space. Further, we\nshow that this gauge invariant description represents networks of unoriented\nloops carrying certain non-negative abelian fluxes created by the harmonic\noscillator prepotentials. The loop network is characterized by $3(d-1)$ gauge\ninvariant integers at every lattice site which is the number of physical\ndegrees of freedom. Time evolution involves local fluctuations of these loops.\nThe loop Hamiltonian is derived. The generalization to SU(N) gauge group is\ndiscussed."
    },
    {
        "anchor": "Locality Properties of a New Class of Lattice Dirac Operators: A new class of lattice Dirac operators $D$ which satisfy the index theorem\nhave been recently proposed on the basis of the algebraic relation\n$\\gamma_{5}(\\gamma_{5}D) + (\\gamma_{5}D)\\gamma_{5} =\n2a^{2k+1}(\\gamma_{5}D)^{2k+2}$. Here $k$ stands for a non-negative integer and\n$k=0$ corresponds to the ordinary Ginsparg-Wilson relation. We analyze the\nlocality properties of Dirac operators which solve the above algebraic\nrelation.\n  We first show that the free fermion operator is analytic in the entire\nBrillouin zone for a suitable choice of parameters $m_{0}$ and $r$, and there\nexists a well-defined ``mass gap'' in momentum space, which in turn leads to\nthe exponential decay of the operator in coordinate space for any finite $k$.\nThis mass gap in the free fermion operator suggests that the operator is local\nfor sufficiently weak background gauge fields. We in fact establish a finite\nlocality domain of gauge field strength for\n$\\Gamma_{5}=\\gamma_{5}-(a\\gamma_{5}D)^{2k+1}$ for any finite $k$, which is\nsufficient for the cohomological analyses of chiral gauge theory. We also\npresent a crude estimate of the localization length defined by an exponential\ndecay of the Dirac operator, which turns out to be much shorter than the one\ngiven by the general Legendre expansion.",
        "positive": "Improvement of N_f=3 lattice QCD with Wilson fermions and tree-level\n  improved gauge action: We determine the parameter c_SW required for O(a)-improvement of the three\nflavor Wilson fermion action together with the tree-level Symanzik improved\ngauge action. The standard improvement condition is employed for a range of\ncouplings. Additionally, we perform a check of the volume independence of c_SW\nand provide a preliminary estimate of the lattice spacing at our largest values\nof g_0^2."
    },
    {
        "anchor": "Monte Carlo studies of three-dimensional O(1) and O(4)\n  \\boldmath{$\u03c6^4$} theory related to BEC phase transition temperatures: The phase transition temperature for the Bose-Einstein condensation (BEC) of\nweakly-interacting Bose gases in three dimensions is known to be related to\ncertain non-universal properties of the phase transition of three-dimensional\nO(2) symmetric $\\phi^4$ theory. These properties have been measured previously\nin Monte Carlo lattice simulations. They have also been approximated\nanalytically, with moderate success, by large $N$ approximations to O($N$)\nsymmetric $\\phi^4$ theory. To begin investigating the region of validity of the\nlarge $N$ approximation in this application, I have applied the same Monte\nCarlo technique developed for the O(2) model ([5]) to O(1) and O(4) theories.\nMy results indicate that there might exist some theoretically unanticipated\nsystematic errors in the extrapolation of the continuum value from lattice\nMonte Carlo results. The final results show that the difference between\nsimulations and NLO large $N$ calculations does not improve significantly from\nN=2 to N=4. This suggests one would need to simulate yet larger $N$'s to see\ntrue large $N$ scaling of the difference. Quite unexpectedly (and presumably\naccidentally), my Monte Carlo result for N=1 seems to give the best agreement\nwith the large $N$ approximation among the three cases.",
        "positive": "de Sitter gravity from lattice gauge theory: We investigate a lattice model for Euclidean quantum gravity based on\ndiscretization of the Palatini formulation of General Relativity. Using Monte\nCarlo simulation we show that while a naive approach fails to lead to a vacuum\nstate consistent with the emergence of classical spacetime, this problem may be\nevaded if the lattice action is supplemented by an appropriate counter term. In\nthis new model we find regions of the parameter space which admit a ground\nstate which can be interpreted as (Euclidean) de Sitter space."
    },
    {
        "anchor": "Lattice QCD determination of patterns of excited baryon states: Energies for excited isospin I=1/2 and I=3/2 states that include the nucleon\nand Delta families of baryons are computed using quenched, anisotropic\nlattices. Baryon interpolating field operators that are used include nonlocal\noperators that provide G_2 irreducible representations of the octahedral group.\nThe decomposition of spin 5/2 or higher spin states is realized for the first\ntime in a lattice QCD calculation. We observe patterns of degenerate energies\nin the irreducible representations of the octahedral group that correspond to\nthe subduction of the continuum spin 5/2 or higher. The overall pattern of\nlow-lying excited states corresponds well to the pattern of physical states\nsubduced to the irreducible representations of the octahedral group.",
        "positive": "Nucleon Axial Form Factor from Lattice QCD: Results for the isovector axial form factors of the proton from a lattice QCD\ncalculation are presented for both point-split and local currents. They are\nobtained on a quenched $16^{3} \\times 24$ lattice at $\\beta= 6.0$ with Wilson\nfermions for a range of quark masses from strange to charm. We determine the\nfinite lattice renormalization for both the local and point-split currents of\nheavy quarks. Results extrapolated to the chiral limit show that the $q^2$\ndependence of the axial form factor agrees reasonably well with experiment. The\naxial coupling constant $g_A$ calculated for the local and the point-split\ncurrents is about 6\\% and 12\\% smaller than the experimental value\nrespectively."
    },
    {
        "anchor": "Perturbative $O(\u03b1_s a)$ matching in static heavy and domain-wall\n  light quark system: We discuss the perturbative $O(\\alpha_s a)$ matching in the static heavy and\ndomain-wall light quark system. The gluon action is the Iwasaki action and the\nlink smearing is performed in the static heavy action. The chiral symmetry of\nthe light quark realized by using the domain-wall fermion formulation does not\nprohibit the mixing of the operators at $O(a)$. The application of $O(a)$\nimprovement to the actual data shows that the B meson decay constant $f_B$, the\nmatrix elements ${\\cal M}_B$ and the B parameter $B_B$ have non-negligible\neffects, while the effect on the SU(3) breaking ratio $\\xi$ is small.",
        "positive": "Systematic uncertainties in parton distribution functions from lattice\n  QCD simulations at the physical point: We present a detailed study of the helicity-dependent and\nhelicity-independent collinear parton distribution functions (PDFs) of the\nnucleon, using the quasi-PDF approach. The lattice QCD computation is performed\nemploying twisted mass fermions with a physical value of the light quark mass.\nWe give a systematic and in-depth account of the salient features entering in\nthe evaluation of quasi-PDFs and their relation to the light-cone PDFs. In\nparticular, we give details for the computation of the matrix elements,\nincluding the study of the various sources of systematic uncertainties, such as\nexcited states contamination. In addition, we discuss the non-perturbative\nrenormalization scheme used here and its systematics, effects of truncating the\nFourier transform and different matching prescriptions."
    },
    {
        "anchor": "Monopoles and the 't Hooft tensor for generic gauge group: We study monopoles and corresponding 't Hooft tensor in a generic gauge\ntheory. This issue is relevant to the understanding of color confinement.",
        "positive": "Determination of light quark masses from the electromagnetic splitting\n  of pseudoscalar meson masses computed with two flavors of domain wall\n  fermions: We determine the light quark masses from lattice QCD simulations\nincorporating the electromagnetic interaction of valence quarks. The meson\nmasses are calculated on lattice QCD configurations generated by the RBC\nCollaboration for two flavors of dynamical domain wall fermions, which are\ncombined with QED configurations generated via quenched non-compact lattice\nQED. The electromagnetic part of the pion mass splitting is found to be\n$m_{\\pi^+}-m_{\\pi^0}=4.12(21)$ MeV, where only the statistical error is quoted,\nand similarly for the kaon, 1.443(55) MeV. Our results for the light quark\nmasses are $m_u^{\\rm\\bar{MS}}$(2 GeV)=$3.02(27)(19)$ MeV, $m_d^{\\rm\\bar{MS}}$(2\nGeV)=$5.49(20)(34)$ MeV, and $m_s^{\\rm\\bar{MS}}$(2 GeV)=$119.5(56)(74)$ MeV,\nwhere the first error is statistical and the second systematic. By averaging\nover $\\pm e$ to cancel ${\\cal O}(e)$ noise exactly on each combined gauge field\nconfiguration, we are able to work at physical $\\alpha=1/137$ and obtain very\nsmall statistical errors. In our calculation, several sources of systematic\nerror remain, including finite volume, non-zero lattice spacing, chiral\nextrapolation, quenched QED, and quenched strange quark, which may be more\nsignificant than the errors quoted above."
    },
    {
        "anchor": "Monte Carlo Simulation of 2-D Quantum Gravity as Open Dynamically\n  Triangulate Random Surfaces: We describe a Monte Carlo procedure for the simulation of dynamically\ntriangulate random surfaces with a boundary (topology of a disk). The algorithm\nkeeps the total number of triangles fixed, while the length of the boundary is\nallowed to fluctuate. The algorithm works in the presence of matter fields. We\nhere present results for the pure gravity case. The algorithm reproduces the\ntheoretical expectations.",
        "positive": "Chiral properties of domain-wall quarks in quenched QCD: We investigate the chiral properties of quenched domain-wall QCD (DWQCD) at\nthe lattice spacings $a^{-1} \\simeq 1$ and 2 GeV for both plaquette and\nrenormalization-group (RG) improved gauge actions. In the case of the plaquette\naction we find that the quark mass defined through the axial Ward-Takahashi\nidentity remains non-vanishing in the DWQCD chiral limit that the bare quark\nmass $m_f\\to 0$ and the length of the fifth dimension $N_s\\to\\infty$,\nindicating that chiral symmetry is not realized with quenched DWQCD up to\n$a^{-1} \\simeq 2$ GeV. The behavior is much improved for the RG-improved gauge\naction: while a non-vanishing quark mass remains in the chiral limit at\n$a^{-1}\\simeq 1$ GeV, the result at $a^{-1}\\simeq 2$ GeV is consistent with an\nexponentially vanishing quark mass in the DWQCD chiral limit, indicating the\nrealization of exact chiral symmetry. An interpretation and implications are\nbriefly discussed."
    },
    {
        "anchor": "Chiral condensate, quark charge and chiral density: We study the topological and fermionic vacuum structure of four-dimensional\nQCD on the lattice by means of correlators of fermionic observables and\ntopological densities. We show the existence of strong local correlations\nbetween the topological charge density and the quark condensate, charge and\nchiral density. By analysis of individual gauge configurations, we visualize\nthat instantons (antiinstantons) carry positive (negative) chirality, whereas\nthe quark charge density fluctuates in sign within instantons.",
        "positive": "Chiral symmetry breaking in (2+1) dimensional QED: We study dynamical mass generation in QED in (2+1) dimensions using\nHamiltonian lattice methods. We use staggered fermions, and perform simulations\nwith explicit dynamical fermions in the chiral limit. We demonstrate that a\nrecently developed method to reduce the fermion sign problem can successfully\nbe applied to this problem. Our results are in agreement with both the strong\ncoupling expansion and with Euclidean lattice simulations."
    },
    {
        "anchor": "Resolving Exceptional Configurations: In lattice QCD with Wilson fermions, exceptional configurations arise in the\nquenched approximation at small quark mass. The origin of these large\npreviously uncontrolled lattice artifacts is identified. A simple well-defined\nprocedure (MQA) is presented which removes the artifacts while preserving the\ncorrect continuum limit.",
        "positive": "Truncated Perfect Actions for Staggered Fermions: We discuss the behavior of free perfect staggered fermions and truncated\nversions thereof. The study includes flavor non-degenerate masses. We suggest a\nnew blocking scheme, which provides excellent locality of the perfect lattice\naction. A truncation procedure adequate for the structure of staggered fermions\nis applied. We consider spectral and thermodynamic properties and compare\ntruncated perfect actions, Symanzik improved and standard staggered fermions in\ntwo and four dimensions."
    },
    {
        "anchor": "Individual Eigenvalue Distributions for the Wilson Dirac Operator: We derive the distributions of individual eigenvalues for the Hermitian\nWilson Dirac Operator D5 as well as for real eigenvalues of the Wilson Dirac\nOperator DW. The framework we provide is valid in the epsilon regime of chiral\nperturbation theory for any number of flavours Nf and for non-zero low energy\nconstants W6, W7, W8. It is given as a perturbative expansion in terms of the\nk-point spectral density correlation functions and integrals thereof, which in\nsome cases reduces to a Fredholm Pfaffian. For the real eigenvalues of DW at\nfixed chirality nu this expansion truncates after at most nu terms for small\nlattice spacing \"a\". Explicit examples for the distribution of the first and\nsecond eigenvalue are given in the microscopic domain as a truncated expansion\nof the Fredholm Pfaffian for quenched D5, where all k-point densities are\nexplicitly known from random matrix theory. For the real eigenvalues of\nquenched DW at small \"a\" we illustrate our method by the finite expansion of\nthe corresponding Fredholm determinant of size nu.",
        "positive": "Chiral perturbation theory in a theta vacuum: We consider chiral perturbation theory (ChPT) with a non-zero theta term. Due\nto the CP violating term, the vacuum of chiral fields is shifted to a\nnon-trivial element on the SU(N_f) group manifold. The CP violation also\nprovides mixing of different CP eigenstates, between scalar and pseudoscalar,\nor vector and axialvector operators. We investigate upto O(theta^2) effects on\nthe mesonic two point correlators of ChPT to the one-loop order. We also\naddress the effects of fixing topology, by using saddle point integration in\nthe Fourier transform with respect to theta."
    },
    {
        "anchor": "Chiral symmetry and spectral properties of the Dirac operator in G2\n  Yang-Mills Theory: We study spontaneous chiral symmetry breaking and the spectral properties of\nthe staggered lattice Dirac operator using quenched gauge configurations for\nthe exceptional group G2, which has a trivial center. In particular we study\nthe system below and above the finite temperature transition and use the\ntemporal boundary conditions of the fermions to probe the system. We evaluate\nseveral observables: The spectral density at the origin, the spectral gap, the\nchiral condensate and the recently proposed dual chiral condensate. We show\nthat chiral symmetry is broken at low temperatures and is restored at high\ntemperatures at the thermodynamic phase transition. Concerning the role of the\nboundary conditions we establish that in all respects the spectral quantities\nbehave for G2 in exactly the same way as for SU(N), when for the latter group\nthe gauge ensemble above T_c is restricted to the sector of configurations with\nreal Polyakov loop.",
        "positive": "Sphaleron transition rate in the classical 1+1 dimensional abelian Higgs\n  model at finite temperature: We compute the sphaleron transition rate in the 1+1 dimensional abelian Higgs\nmodel at finite temperature, by real time simulation using the classical\ncanonical ensemble."
    },
    {
        "anchor": "Hadron masses from fixed topology simulations: parity partners and SU(2)\n  Yang-Mills results: Lattice QCD simulations tend to get stuck in a single topological sector at\nfine lattice spacing, or when using chirally symmetric quarks. In such cases\ncomputed observables differ from their full QCD counterparts by finite size\neffects, which need to be understood on a quantitative level. We discuss\nextensions of existing relations from the literature between correlation\nfunctions at fixed topology and hadron masses at unfixed topology. Particular\nfocus is put on disentangling positive and negative parity states, which mix,\nwhen the topological charge is fixed. We also present numerical results for\nSU(2) Yang-Mills Theory.",
        "positive": "Continuous Chiral Transition in Strongly Coupled Compact QED with the\n  Standard Torus Topology: We analyze the phase diagram of compact QED on the torus with a chirally\nsymmetric four fermion interaction added to the usual Wilson action. Inside a\nmean field approximation for the four fermion term, a line of first order phase\ntransitions and another one of second order are found in the $(\\beta, G)$\nplane. Approaching the second order line a continuum limit can be defined.\nCritical exponents vary along this line in a similar way as in the non-compact\nmodel, suggesting that a non trivial interacting continuum theory can be\nconstructed."
    },
    {
        "anchor": "A study of center vortices in SU(2) and SU(3) gauge theories: We show how center vortices and Abelian monopoles both appear as local gauge\nambiguities in the Laplacian Center gauge. Numerical results, for SU(2) and\nSU(3), support the view that the string tension obtained in the\ncenter-projected theory matches the full string tension when the continuum\nlimit is taken.",
        "positive": "Peculiarities in the Spectrum of the Adjoint Scalar Kinetic Operator in\n  Yang-Mills Theory: We study the spectrum of low-lying eigenmodes of the kinetic operator for\nscalar particles, in the color adjoint representation of Yang-Mills theory. The\nkinetic operator is the covariant Laplacian, plus a constant which serves to\nrenormalize mass. In the pure gauge theory, our data indicates that the\ninterval between the lowest eigenvalue and the mobility edge tends to infinity\nin the continuum limit. On these grounds, it is suggested that the perturbative\nexpression for the scalar propagator may be misleading even at distance scales\nthat are small compared to the confinement scale. We also measure the density\nof low-lying eigenmodes, and find a possible connection to multi-critical\nmatrix models of order m=1."
    },
    {
        "anchor": "Determination of $c_\\mathrm A$ in three-flavour lattice QCD with Wilson\n  fermions and tree-level improved gauge action: We report on an ongoing non-perturbative determination of the improvement\ncoefficient of the axial current, $c_\\mathrm A$, with three flavours of\ndynamical $\\mathrm O(a)$ improved Wilson quarks and tree-level Symanzik\nimproved gauge action. Our computations are based on simulations with the\nopenQCD code. The improvement condition for a range of couplings is formulated\nwith Schr\\\"odinger functional boundary conditions and imposed along a line of\nconstant physics in parameter space. Our analysis involves correlation\nfunctions with boundary wave functions such that a large sensitivity to\n$c_\\mathrm A$ can be reached by exploiting the PCAC relation with two different\npseudoscalar states.",
        "positive": "I=2 Pion Scattering Phase Shift with Wilson Fermions: We present results of phase shift for I=2 $S$-wave $\\pi\\pi$ system with the\nWilson fermions in the quenched approximation. The finite size method proposed\nby L\\\"uscher is employed, and calculations are carried out at $\\beta=5.9$\n($a^{-1}=1.934(16)$ GeV from $m_\\rho$) on $24^3 \\times 60$, $32^3 \\times 60$,\nand $48^3 \\times 60$ lattices."
    },
    {
        "anchor": "The three-particle system on a torus: Based on Lippmann-Schwinger equation approach, we discuss a three-particle\nsystem in finite volume. A set of equations which relate the discrete\nfinite-volume energies to the scattering amplitudes are derived under the\napproximation of the isobar model relevant for the case of narrow two- and\nthree-body resonances.",
        "positive": "Lattice simulation of $SU(2)$ dark glueball with machine learning: We study the mass and scattering cross section of $SU(2)$ glueballs as dark\nmatter candidates using lattice simulations. We employ both naive and improved\n$SU(2)$ gauge actions in $3+1$ dimensions with several $\\beta$ values, and\nadopt both the tranditional Monte Carlo method and the flow-based model based\non machine learning techniques to generate lattice configurations. The mass of\nthe scalar glueball with $J^{PC}=0^{++}$ and the NBS wave function are\ncalculated. Using the Runge-Kutta method, we extract the glueball interaction\npotential and scattering cross section. From the observational constraints, we\nobtain the lower bound of the mass of scalar glueball candidates as potential\ncomponents of dark matter."
    },
    {
        "anchor": "Towards a composite Higgs and a partially composite top quark: We have calculated quantities of interest to a theory of compositeness. The\nlattice model, approximating the candidate theory, is the SU(4) gauge theory\ncoupled to fermions in two color representations. For the composite Higgs, a\ncurrent correlator gives one of the ingredients of the effective Higgs\npotential. For the partially composite top quark, we have hyperbaryon matrix\nelements that govern mixing of the fundamental quark with its heavy composite\npartner. The matrix elements turn out to be so small that the theory is\ndisfavored as a source of a realistic top mass.",
        "positive": "High precision renormalization of the flavour non-singlet Noether\n  currents in lattice QCD with Wilson quarks: We determine the non-perturbatively renormalized axial current for O($a$)\nimproved lattice QCD with Wilson quarks. Our strategy is based on the chirally\nrotated Schr\\\"odinger functional and can be generalized to other finite (ratios\nof) renormalization constants which are traditionally obtained by imposing\ncontinuum chiral Ward identities as normalization conditions. Compared to the\nlatter we achieve an error reduction up to one order of magnitude. Our results\nhave already enabled the setting of the scale for the $N_{\\rm f}=2+1$ CLS\nensembles [1] and are thus an essential ingredient for the recent $\\alpha_s$\ndetermination by the ALPHA collaboration [2]. In this paper we shortly review\nthe strategy and present our results for both $N_{\\rm f}=2$ and $N_{\\rm f}=3$\nlattice QCD, where we match the $\\beta$-values of the CLS gauge configurations.\nIn addition to the axial current renormalization, we also present precise\nresults for the renormalized local vector current."
    },
    {
        "anchor": "Lattice Gauge Theory of Three Dimensional Thirring Model: Three dimensional Thirring model with $N$ four-component Dirac fermions,\nreformulated as a lattice gauge theory, is studied by computer simulation.\nAccording to an $8^{3}$ data and preliminary $16^3$ data, chiral symmetry is\nfound to be spontaneously broken for $N=2,\\;4$ and 6. $N=2$ data exhibits long\ntail of the non-vanishing chiral condensate into weak coupling region, and\n$N=6$ case shows phase separation between the strong coupling region and the\nweak coupling region. Although the comparison between $8^3$ data and $16^3$\ndata shows large finite volume effects, an existence of the critical fermion\nflavor number $N_{{\\rm cr}}$ $(2<N_{{\\rm cr}}<6)$ for which the chiral behavior\nchanges its character, is suggested by the current numerical data.",
        "positive": "A finite-volume matrix Hamiltonian model for a Delta -> nucleon-pion\n  system: A matrix Hamiltonian model is developed to address the finite-volume effects\nappearing in studies of baryon resonances in lattice QCD. The Hamiltonian model\nincludes interaction terms in a transparent way, and can be readily generalized\nto address multi-channel problems. The eigenvalue equation of the model is\nexactly solvable, and can be matched onto chiral effective field theory. The\nmodel is investigated in the case of Delta -> nucleon-pion scattering. A robust\nmethod for determining the resonance parameters from lattice QCD is developed.\nIt involves constraining the free parameters of the model based on the lattice\nspectrum in question. The method is tested in the context of a set of\npseudodata, and a picture of the model-dependence is obtained by examining a\nvariety of regularization schemes in the model. A comparison is made with the\nLuescher method, and it is found that the matrix Hamiltonian method is equally\nrobust. Both methods are tested in a more realistic scenario, where a\nbackground interaction corresponding to direct nucleon-pion scattering is\nincorporated into the pseudodata. The resulting extraction of the resonance\nparameters associated with the Delta baryon resonance provides evidence that an\neffective field theory style of approach yields a successful realization of\nfinite-volume effects in the context of baryon resonances."
    },
    {
        "anchor": "Gauge-gravity duality -- Super Yang Mills Quantum Mechanics: We describe the conjectured holographic duality between Yang-Mills quantum\nmechanics and type IIa string theory. This duality allows us to use lattice\nMonte Carlo simulations to probe the physics of the gravitational theory - for\nexample, at low energies it provides a computation of black hole entropy in\nterms of a sum over microstates of the dual gauge theory. Numerical results are\npresented of the 4 supercharge theory at finite temperature",
        "positive": "Phases of SU(3) Gauge Theories with Fundamental Quarks via Dirac\n  Spectral Density: We propose that, in SU(3) gauge theories with fundamental quarks, confinement\ncan be inferred from spectral density of the Dirac operator. This stems from\nthe proposition that its possible behaviors are exhausted by three distinct\ntypes (Fig.1). The monotonic cases are standard and entail confinement with\nvalence chiral symmetry breaking (A) or the lack of both (C,C'). The bimodal\n(anomalous) option (B) was frequently regarded as an artifact (lattice or\nother) in previous studies, but we show for the first time that it persists in\nthe continuum limit, and conclude that it informs of a non-confining phase with\nbroken valence chiral symmetry. This generalization rests on the following.\n$(\\alpha)$ We show that bimodality in $N_f$=0 theory past deconfinement\ntemperature $T_c$ is stable with respect to removal of both infrared and\nultraviolet cutoffs, indicating that anomalous phase is not an artifact.\n$(\\beta)$ We demonstrate that transition to bimodality in $N_f$=0 is\nsimultaneous with the loss of confinement: anomalous phase occurs for $T_c < T\n< T_{ch}$, where $T_{ch}$ is the valence chiral restoration temperature.\n$(\\gamma)$ Evidence is presented for thermal anomalous phase in $N_f$=2+1 QCD\nat physical quark masses, whose onset too coincides with the conventional\n\"crossover $T_c$''. We conclude that the anomalous regime $T_c < T < T_{ch}$ is\nvery likely a feature of nature's strong interactions. $(\\delta)$ Our past\nstudies of zero-temperature $N_f$=12 theories revealed that bimodality also\narises via purely light-quark effects. As a result, we expect to encounter\nanomalous phase on generic paths to valence chiral restoration. We predict its\nexistence also for $N_f$ massless flavors ($T=0$) in the range $N_f^c < N_f <\nN_f^{ch}$, where $N_f^c$ could be quite low. Conventional arguments would\nassociate $N_f^{ch}$ with the onset of conformal window."
    },
    {
        "anchor": "Mass effects on the QCD $\u03b2$-function: In this study we present lattice results on the QCD $\\beta$-function in the\npresence of quark masses. The $\\beta$-function is calculated to three loops in\nperturbation theory and for improved lattice actions; it is extracted from the\nrenormalization of the coupling constant $Z_g$. The background field method is\nused to compute $Z_g$, where it is simply related to the background gluon field\nrenormalization constant $Z_A$. We focus on the quark mass effects in the\nbackground gluon propagator; the dependence of the QCD $\\beta$-function on the\nnumber of colors $N_c$, the number of fermionic flavors $N_f$ and the quark\nmasses, is shown explicitly. The perturbative results of the QCD\n$\\beta$-function will be applied to the precise determination of the strong\ncoupling constant, calculated by Monte Carlo simulations removing the mass\neffects from the nonperturbative Green's functions.",
        "positive": "Universality and RG-improved gauge actions: The reference energy scale r_0 is evaluated for RG-improved Iwasaki and DBW2\ngauge actions (N_f = 0), at values of the deconfinement coupling beta_c\ncorresponding to N_t = 3,4,6,8. The universality of r_0 T_c between Iwasa ki\nand Wilson action is confirmed; the scaling behaviour and the influence of th e\nviolation of positivity in the extraction of effective masses are investigated."
    },
    {
        "anchor": "Confining Configurations in QCD and Relation to Rigid Strings: The gauge field configurations of QCD gauge fields in the infrared regime are\nobtained by magnetic symmetry condition. The effective dual action exhibits\ndual Meissner effect with quarks included. A string representation of this\naction corresponds to rigid string.",
        "positive": "Constraints for the semileptonic $B \\to D^{(*)}$ form factors from\n  lattice QCD simulations of two-point correlation functions: In this work we present the first non-perturbative determination of the\nhadronic susceptibilities that constrain the form factors entering the\nsemileptonic $B \\to D^{(*)} \\ell \\nu_\\ell $ transitions due to unitarity and\nanalyticity. The susceptibilities are obtained by evaluating moments of\nsuitable two-point correlation functions obtained on the lattice. Making use of\nthe gauge ensembles produced by the Extended Twisted Mass Collaboration with\n$N_f = 2+1+1$ dynamical quarks at three values of the lattice spacing ($a\n\\simeq 0.062, 0.082, 0.089$ fm) and with pion masses in the range $\\simeq 210 -\n450$ MeV, we evaluate the longitudinal and transverse susceptibilities of the\nvector and axial-vector polarization functions at the physical pion point and\nin the continuum and infinite volume limits. The ETMC ratio method is adopted\nto reach the physical $b$-quark mass $m_b^{phys}$. At zero momentum transfer\nfor the $b \\to c$ transition we get $\\chi_{0^+}(m_b^{phys}) = 7.58\\,(59) \\cdot\n10^{-3}$, $\\chi_{1^-}(m_b^{phys}) = 6.72\\,(41) \\cdot 10^{-4}$ GeV$^{-2}$,\n$\\chi_{0^-}(m_b^{phys}) = 2.58\\,(17) \\cdot 10^{-2}$ and $\\chi_{1^+}(m_b^{phys})\n= 4.69\\,(30) \\cdot 10^{-4}$ GeV$^{-2}$ for the scalar, vector, pseudoscalar and\naxial susceptibilities, respectively. In the case of the vector and\npseudoscalar channels the one-particle contributions due to $B_c^*$- and\n$B_c$-mesons are evaluated and subtracted to improve the bounds, obtaining:\n$\\chi_{1^-}^{sub}(m_b^{phys}) = 5.84\\,(44) \\cdot 10^{-4}$ GeV$^{-2}$ and\n$\\chi_{0^-}^{sub}(m_b^{phys}) = 2.19\\,(19) \\cdot 10^{-2}$."
    },
    {
        "anchor": "Simulated Tempering: A New Monte Carlo Scheme: We propose a new global optimization method ({\\em Simulated Tempering}) for\nsimulating effectively a system with a rough free energy landscape (i.e. many\ncoexisting states) at finite non-zero temperature. This method is related to\nsimulated annealing, but here the temperature becomes a dynamic variable, and\nthe system is always kept at equilibrium. We analyze the method on the Random\nField Ising Model, and we find a dramatic improvement over conventional\nMetropolis and cluster methods. We analyze and discuss the conditions under\nwhich the method has optimal performances.",
        "positive": "QCD at non-zero density and canonical partition functions with Wilson\n  fermions: We present a reduction method for Wilson Dirac fermions with non-zero\nchemical potential which generates a dimensionally reduced fermion matrix. The\nsize of the reduced fermion matrix is independent of the temporal lattice\nextent and the dependence on the chemical potential is factored out. As a\nconsequence the reduced matrix allows a simple evaluation of the Wilson fermion\ndeterminant for any value of the chemical potential and hence the exact\nprojection to the canonical partition functions."
    },
    {
        "anchor": "The Planar Thirring Model with K\u00e4hler-Dirac Fermions: K\\\"ahler's geometric approach in which relativistic fermion fields are\ntreated as differential forms is applied in three spacetime dimensions. It is\nshown that the resulting continuum theory is invariant under global\nU($N)\\otimes$U($N)$ field transformations, and has a parity-invariant mass\nterm, both symmetries shared in common with staggered lattice fermions. The\nformalism is used to construct a version of the Thirring model with contact\ninteractions between conserved Noether currents. Under reasonable assumptions\nabout field rescaling after quantum corrections, a more general interaction\nterm is derived, sharing the same symmetries but now including terms which\nentangle spin and taste degrees of freedom, which exactly coincides with the\nleading terms in the staggered lattice Thirring model in the long-wavelength\nlimit. Finally truncated versions of the theory are explored; it is found that\nexcluding scalar and pseudoscalar components leads to a theory of six-component\nfermion fields describing particles with spin 1, with fermion and antifermion\ncorresponding to states with definite circular polarisation. In the UV limit\nonly transverse states with just four non-vanishing components propagate.\nImplications for the description of dynamics at a strongly interacting\nrenormalisation-group fixed point are discussed.",
        "positive": "On the ratio of string tensions in the 3D Z_4 lattice gauge theory: It was recently pointed out that simple scaling properties of Polyakov\ncorrelation functions of gauge systems in the confining phase suggest that the\nratios of k-string tensions in the low temperature region is constant up to\nterms of order T^3. Here we argue that, at least in a three-dimensional Z_4\ngauge model, the above ratios are constant in the whole confining phase. This\nresult is obtained by combining numerical experiments with known exact results\non the mass spectrum of an integrable two-dimensional spin model describing the\ninfrared behaviour of the gauge system near the deconfining transition."
    },
    {
        "anchor": "Stochastic quantization at nonzero chemical potential: Lattice QCD at finite chemical potential is difficult due to the sign\nproblem. We use stochastic quantization and complex Langevin dynamics to study\nthis issue. First results for QCD in the hopping expansion are encouraging.\nU(1) and SU(3) one link models are used to gain further insight into why the\nmethod appears to be successful.",
        "positive": "Axial U(1) current in Grabowska and Kaplan's formulation: Recently, Grabowska and Kaplan suggested a non-perturbative formulation of a\nchiral gauge theory, which consists of the conventional domain-wall fermion and\na gauge field that evolves by the gradient flow from one domain wall to the\nother. In this paper, we discuss the U(1) axial-vector current in 4 dimensions\nusing this formulation. We introduce two sets of domain-wall fermions belonging\nto complex conjugate representations so that the effective theory is a\n4-dimensional vector-like gauge theory. Then, as a natural definition of the\naxial-vector current, we consider a current that generates the simultaneous\nphase transformations for the massless modes in 4 dimensions. However, this\ncurrent is exactly conserved and does not reproduce the correct anomaly. In\norder to investigate this point precisely, we consider the mechanism of the\nconservation. We find that this current includes not only the axial current on\nthe domain wall but also a contribution from the bulk, which is non-local in\nthe sense of 4-dimensional fields. Therefore, the local current is obtained by\nsubtracting the bulk contribution from it."
    },
    {
        "anchor": "Charmonium correlators and spectral functions at finite temperature: We study charmonium correlators and spectral functions in quenched QCD, using\nClover improved Wilson fermions on very fine (0.015 fm) isotropic lattices at\n0.75 Tc and 1.5 Tc. We use a new approach to distinguish the zero mode\ncontribution from the other contributions. Once this is removed, we find that\nthe ratios of correlators to reconstructed correlators remain almost unity at\nall distances. The ground state peaks of spectral functions obtained at 0.75 Tc\nare reliable and robust. The present accuracy and limited number of points in\nthe temporal direction at 1.5 Tc do not allow for a reliable conclusion about a\npossible melting of charmonium states in the QGP.",
        "positive": "Two-Baryon Systems with Twisted Boundary Conditions: We explore the use of twisted boundary conditions in extracting the nucleon\nmass and the binding energy of two-baryon systems, such as the deuteron, from\nLattice QCD calculations. Averaging the results of calculations performed with\nperiodic and anti-periodic boundary conditions imposed upon the light-quark\nfields, or other pair-wise averages, improves the volume dependence of the\ndeuteron binding energy from ~exp(-kappa*L)/L to ~exp(-sqrt(2)kappa*L)/L.\nHowever, a twist angle of pi/2 in each of the spatial directions improves the\nvolume dependence from ~exp(-kappa*L)/L to ~exp(-2kappa*L)/L. Twist averaging\nthe binding energy with a random sampling of twist angles improves the volume\ndependence from ~exp^(-kappa*L)/L to ~exp(-2kappa*L)/L, but with a standard\ndeviation of ~exp(-kappa*L)/L, introducing a signal-to-noise issue in modest\nlattice volumes. Using the experimentally determined phase shifts and mixing\nangles, we determine the expected energies of the deuteron states over a range\nof cubic lattice volumes for a selection of twisted boundary conditions."
    },
    {
        "anchor": "Improving Lattice Quark Actions: We explore the first stage of the Symanzik improvement program for lattice\nDirac fermions, namely the construction of doubler-free, highly improved\nclassical actions on isotropic as well as anisotropic lattices (where the\ntemporal lattice spacing, a_t, is smaller than the spatial one). Using field\ntransformations to eliminate doublers, we derive the previously presented\nisotropic D234 action with O(a^3) errors, as well as anisotropic D234 actions\nwith O(a^4) or O(a_t^3, a^4) errors. Besides allowing the simulation of heavy\nquarks within a relativistic framework, anisotropic lattices alleviate\npotential problems due to unphysical branches of the quark dispersion relation\n(which are generic to improved actions), facilitate studies of lattice\nthermodynamics, and allow accurate mass determinations for particles with bad\nsignal/noise properties, like glueballs and P-state mesons. We also show how\nfield transformations can be used to completely eliminate unphysical branches\nof the dispersion relation. Finally, we briefly discuss future steps in the\nimprovement program.",
        "positive": "Universality of a truncated sigma-model: Bosonic quantum field theories, even when regularized using a finite lattice,\npossess an infinite dimensional Hilbert space and, therefore, cannot be\nsimulated in quantum computers with a finite number of qubits. A truncation of\nthe Hilbert space is then needed and the physical results are obtained after a\ndouble limit: one to remove the truncation and another to remove the regulator\n(the continuum limit). A simpler alternative is to find a model with a finite\ndimensional Hilbert space belonging to the same universality class as the\ncontinuum model (a \"qubitization\"), so only the space continuum limit is\nrequired. A qubitization of the $1+1$ dimensional asymptotically free $O(3)$\nnonlinear $\\sigma$-model based on ideas of non-commutative geometry was\npreviously proposed arXiv:1903.06577 and, in this paper, we provide evidence\nthat it reproduces the physics of the $\\sigma$-model both in the infrared and\nthe ultraviolet regimes."
    },
    {
        "anchor": "Finite-Size Effects in the Interface of 3D Ising Model: The interface between domains of opposite magnetization in the 3D Ising model\nnear the critical temperature displays universal finite-size effects which can\nbe described in terms of a gaussian model of capillary waves. It turns out that\nthese finite-size corrections depend rather strongly on the shape of the\nlattice. This prediction, which has no adjustable parameters, is tested and\naccurately verified for various lattice shapes by means of numerical\nsimulations with a cluster algorithm. This supports also a long-standing\nconjecture on the finite-size effects in Wilson loops of Lattice Gauge\nTheories.",
        "positive": "Excluded-volume effects for a hadron gas in Yang-Mills theory: When the multiplicities of particles produced in heavy-ion collisions are\nfitted to the hadron-resonance-gas model, excluded-volume effects play a\nsignificant role. In this work, we study the impact of such effects on the\nequation of state of pure Yang-Mills theory at low temperatures, comparing the\npredictions of the statistical model with lattice results. In particular, we\npresent a detailed analysis of the SU(2) and SU(3) Yang-Mills theories: we find\nthat, for both of them, the best fits to the equilibrium thermodynamic\nquantities are obtained when one assumes that the volume of different glueball\nstates is inversely proportional to their mass. The implications of these\nfindings for QCD are discussed."
    },
    {
        "anchor": "The infrared behavior of lattice QCD Green's functions: We investigate different aspects of lattice QCD in Landau gauge using Monte\nCarlo simulations. In particular, we focus on the low momentum behavior of\ngluon and ghost propagators. The gauge group is SU(3). Different systematic\neffects on the gluon and ghost propagators are studied, e.g. the dependence on\nthe choice of Gribov copies or the influence of dynamical Wilson fermions. We\ncompare our data with results from studies of Dyson-Schwinger equations for the\ngluon and ghost propagators. We demonstrate that the infrared behavior of both\npropagators, as found in this thesis, is consistent with different criteria for\nconfinement. However, the running coupling constant, given as a\nrenormalization-group-invariant combination of the gluon and ghost dressing\nfunctions, does not expose a finite infrared fixed point. We also report on a\nfirst nonperturbative computation of the SU(3) ghost-gluon-vertex\nrenormalization constant and on an investigation of the spectral properties of\nthe Faddeev-Popov operator.",
        "positive": "Hadronic decays from the lattice: I review the lattice QCD approach to determining hadronic decay transitions.\nExamples considered include rho to pi pi; b_1 to pi omega; hybrid meson decays\nand scalar meson decays. I discuss what lattices can provide to help understand\nthe composition of hadrons."
    },
    {
        "anchor": "Correlations of Abelian monopoles in quark-gluon plasma: In this paper the properties of thermal Abelian monopoles in the\ndeconfinement phase of the SU(2) gluodynamics are considered. In particular, to\nstudy the properties of the Abelian monopole component of QGP we calculate\nthree-point correlation functions of monopoles for different temperatures from\nthe region $T/T_c \\in (1.5, 6.8)$. The results of the calculation show that the\nthree-point correlation functions can be described by independent pair\ncorrelations of monopoles. From this one can conclude that the system of\nAbelian monopoles in QGP reveals the properties of a dilute gas. In addition,\none can assert that the interaction between Abelian monopoles is a pair\ninteraction and there are no three-particle forces acting between monopoles.",
        "positive": "Scattering of unstable particles in a finite volume: the case of pi rho\n  scattering and the a1(1260) resonance: We present a way to evaluate the scattering of unstable particles quantized\nin a finite volume with the aim of extracting physical observables for infinite\nvolume from lattice data. We illustrate the method with the $\\pi\\rho$\nscattering which generates dynamically the axial-vector $a_1(1260)$ resonance.\nEnergy levels in a finite box are evaluated both considering the $\\rho$ as a\nstable and unstable resonance and we find significant differences between both\ncases. We discuss how to solve the problem to get the physical scattering\namplitudes in the infinite volume, and hence phase shifts, from possible\nlattice results on energy levels quantized inside a finite box."
    },
    {
        "anchor": "Lattice calculations of the leading hadronic contribution to (g-2)_mu: We report on our ongoing project to calculate the leading hadronic\ncontribution to the anomalous magnetic moment of the muon a_mu^HLO using two\ndynamical flavours of non-perturbatively O(a) improved Wilson fermions. In this\nstudy, we changed the vacuum polarisation tensor to a combination of local and\npoint-split currents which significantly reduces the numerical effort.\nPartially twisted boundary conditions allow us to improve the momentum\nresolution of the vacuum polarisation tensor and therefore the determination of\nthe leading hadronic contribution to (g-2)_mu. We also extended the range of\nensembles to include a pion mass below 200 MeV which allows us to check the\nnon-trivial chiral behaviour of a_mu^HLO.",
        "positive": "Inclusive semi-leptonic $B_{(s)}$ mesons decay at the physical $b$ quark\n  mass: We address the non-perturbative calculation of the decay rate of inclusive\nsemi-leptonic $B_{(s)}$ mesons decays from lattice QCD. Precise theoretical\nStandard Model predictions are key ingredients in searches for new physics.\nThis type of computation may eventually provide new insight into the\nlong-standing tension between the inclusive and exclusive determinations of the\nCKM matrix elements $|V_{cb}|$ and $|V_{ub}|$. We perform a pilot lattice\ncomputation for $B_s \\rightarrow X_c \\, l \\nu_l$ and improve on existing\ntechniques. The valence-quark masses in our simulations are approximately\nphysical for the domain-wall strange and charm quarks as well as for the bottom\nquark, for which we use a relativistic heavy quark effective action. We report\non our progress and discuss future plans towards a first study with fully\ncontrolled systematic effects."
    },
    {
        "anchor": "Taste symmetry breaking with HYP-smeared staggered fermions: We study the impact of hypercubic (HYP) smearing on the size of taste\nbreaking for staggered fermions, comparing to unimproved and to asqtad-improved\nstaggered fermions. As in previous studies, we find a substantial reduction in\ntaste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on\nlattices with spacing $a\\approx 0.1 $fm). In addition, we observe that\ndiscretization effects of next-to-leading order in the chiral expansion (${\\cal\nO}(a^2 p^2)$) are markedly reduced by HYP smearing. Compared to asqtad valence\nfermions, we find that taste-breaking in the pion spectrum is reduced by a\nfactor of 2.5-3, down to a level comparable to the expected size of generic\n${\\cal O}(a^2)$ effects. Our results suggest that, once one reaches a lattice\nspacing of $a\\approx 0.09 $fm, taste-breaking will be small enough after HYP\nsmearing that one can use a modified power counting in which ${\\cal O}(a^2) \\ll\n{\\cal O}(p^2)$, simplify fitting to phenomenologically interesting quantities.",
        "positive": "Abelian spatial string tension in finite temperature SU(2) gauge theory: We investigate Abelian and monopole contributions to spatial string tension\nin the deconfined phase of finite temperature SU(2) gauge theory without\nimposing any gauge fixing conditions. Lattice calculations of non-Abelian and\nAbelian spatial string tensions from the Wilson action at gauge coupling\n$\\beta=2.74$ and lattice volume $24^3\\times{N_t}$ $(N_{t}=\\left\\{\n24,8,6,4,2)\\right\\}$ show that these string tensions agree with each other\nwithin error bars at any adopted value of $N_t$, which implies Abelian\ndominance. From measurements of non-Abelian, Abelian, and monopole forces that\narise from the corresponding spatial string tension, furthermore, we find the\ntendency that the monopole contribution to the spatial string tension can be\nalmost as large as the non-Abelian and Abelian ones. The temperature dependence\nof the calculated non-Abelian and Abelian spatial string tensions allows us to\nconclude that the concept of dimensional reduction holds both for non-Abelian\nand Abelian sectors at temperatures higher than twice the critical temperature."
    },
    {
        "anchor": "Domain Wall Fermion QCD with the Exact One Flavor Algorithm: Lattice QCD calculations including the effects of one or more non-degenerate\nsea quark flavors are conventionally performed using the Rational Hybrid Monte\nCarlo (RHMC) algorithm, which computes the square root of the determinant of\n$\\mathscr{D}^{\\dagger} \\mathscr{D}$, where $\\mathscr{D}$ is the Dirac operator.\nThe special case of two degenerate quark flavors with the same mass is\ndescribed directly by the determinant of $\\mathscr{D}^{\\dagger} \\mathscr{D}$\n--- in particular, no square root is necessary --- enabling a variety of\nalgorithmic developments, which have driven down the cost of simulating the\nlight (up and down) quarks in the isospin-symmetric limit of equal masses. As a\nresult, the relative cost of single quark flavors --- such as the strange or\ncharm --- computed with RHMC has become more expensive. This problem is even\nmore severe in the context of our measurements of the $\\Delta I = 1/2$ $K\n\\rightarrow \\pi \\pi$ matrix elements on lattice ensembles with $G$-parity\nboundary conditions, since $G$-parity is associated with a doubling of the\nnumber of quark flavors described by $\\mathscr{D}$, and thus RHMC is needed for\nthe isospin-symmetric light quarks as well. In this paper we report on our\nimplementation of the exact one flavor algorithm (EOFA) introduced by the TWQCD\ncollaboration for simulations including single flavors of domain wall quarks.\nWe have developed a new preconditioner for the EOFA Dirac equation, which both\nreduces the cost of solving the Dirac equation and allows us to re-use the bulk\nof our existing high-performance code. Coupling these improvements with careful\ntuning of our integrator, the time per accepted trajectory in the production of\nour 2+1 flavor $G$-parity ensembles with physical pion and kaon masses has been\ndecreased by a factor of 4.2.",
        "positive": "Closed flux tubes in D=2+1 SU(N) gauge theories: dynamics and effective\n  string description: We extend our earlier calculations of the spectrum of closed flux tubes in\nSU(N) gauge theories in 2+1 dimensions, with a focus on questions raised by\nrecent theoretical progress on the effective string action of long flux tubes\nand the world-sheet action for flux tubes of moderate lengths. Our new\ncalculations in SU(4) and SU(8) provide evidence that the leading O(1/l^gamma)\nnon-universal correction to the flux tube ground state energy does indeed have\na power gamma greater than or equal to 7. We perform a study in SU(2), where we\ncan traverse the length at which the Nambu-Goto ground state becomes tachyonic,\nto obtain an all-N view of the spectrum. Our comparison of the k=2 flux tube\nexcitation energies in SU(4) and SU(6) suggests that the massive world sheet\nexcitation associated with the k=2 binding has a scale that knows about the\ngroup and hence the theory in the bulk, and we comment on the potential\nimplications of world sheet massive modes for the bulk spectrum. We provide a\nquantitative analysis of the surprising (near-)orthogonality of flux tubes\ncarrying flux in different SU(N) representations, which implies that their\nscreening by gluons is highly suppressed even at small N."
    },
    {
        "anchor": "Infrared physics of the $\\mathrm{SU}(2)$ Georgi-Glashow crossover\n  transition: We perform a lattice study of the phase transition in the $\\mathrm{SU}(2)$\nGeorgi-Glashow model in three dimensions, where the gauge symmetry is broken to\n$\\mathrm{U}(1)$ by the Higgs mechanism and a photon-like state appears. Due to\ncondensation of monopoles the photon acquires a mass, which depends on the\nnumber density of the monopoles. We show that the monopole density can be\nrenormalised on the lattice using gradient flow. Our preliminary results\nsuggest that Polyakov's semiclassical relation between the photon mass and the\nrenormalised monopole density is valid also at the nonperturbative level.",
        "positive": "Resonances in an external field: the 1+1 dimensional case: Using non-relativistic effective field theory in 1+1 dimensions, we\ngeneralize Luescher's approach for resonances in the presence of an external\nfield. This generalized approach provides a framework to study the\ninfinite-volume limit of the form factor of a resonance determined in lattice\nsimulations."
    },
    {
        "anchor": "What we can learn from two-dimensional QCD-like theories at finite\n  density: We study generic properties of strongly interacting matter at finite density\nas relevant to heavy-ion collisions at moderate beam energies or the physics of\nneutron stars and their mergers. Because of the fermion-sign problem in lattice\nQCD, here we simulate QCD-like theories without this problem at finite density.\nThese theories (two-color QCD, G2-QCD, or adjoint QCD) typically contain\nbosonic baryons, for example diquarks, or other more exotic states of matter.\nIt is therefore important to understand the effects of such bosonic matter and\ndisentangle them from fermionic baryons where they exist to draw conclusions\nfor QCD. Simulations of these theories, for instance G2-QCD, reveal an\ninteresting and rich phase diagram at zero temperature. Many open questions\narise, partly due to the lack of high precision or large volume/continuum data.\nThis is the reason why we study two-dimensional QCD-like theories. In this\ncontribution we shall discuss differences between QCD-like theories at baryon\nchemical and isospin chemical potential. Furthermore we present simulation\nresults on the phase diagram and spectroscopy at finite density for G2- and\ntwo-color-QCD and compare it to free lattice fermions.",
        "positive": "Spherically-Symmetric Random Walks in Noninteger Dimension: A previous paper (hep-lat/9311011) proposed a new kind of random walk on a\nspherically-symmetric lattice in arbitrary noninteger dimension $D$. Such a\nlattice avoids the problems associated with a hypercubic lattice in noninteger\ndimension. This paper examines the nature of spherically-symmetric random walks\nin detail. We perform a large-time asymptotic analysis of these random walks\nand use the results to determine the Hausdorff dimension of the process. We\nobtain exact results in terms of Hurwitz functions (incomplete zeta functions)\nfor the probability of a walker going from one region of the spherical lattice\nto another. Finally, we show that the probability that the paths of $K$\nindependent random walkers will intersect vanishes in the continuum limit if\n$D> {{2K}\\over{K-1}}$."
    },
    {
        "anchor": "Bottomonium and B results from full lattice QCD: We have developed two methods for handling $b$ quarks in lattice QCD. One\nuses NRQCD (now improved to include radiative corrections) and the other uses\nHighly Improved Staggered Quarks (HISQ), extrapolating to the $b$ quark from\nlighter masses and using multiple lattice spacings to control discretisation\nerrors. Comparison of results for the two different methods gives confidence in\nestimates of lattice QCD systematic errors, since they are very different in\nthese two cases. Here we show results for heavyonium hyperfine splittings and\nvector current-current correlator moments using HISQ quarks, to add to earlier\nresults testing the heavy HISQ method with pseudoscalar mesons. We also show\nthe form factor for $B \\rightarrow \\pi l \\nu$ decay at zero recoil using NRQCD\n$b$ quarks and $u/d$ quarks with physical masses. This allows us to test the\nsoft pion theorem relation ($f_0(q^2_{max})=f_B/f_{\\pi}$) accurately and we\nfind good agreement as $M_{\\pi} \\rightarrow 0$. }",
        "positive": "Investigating Yang-Mills theory and Confinement as a function of the\n  spatial volume: We study the volume dependence of electric flux energies for SU(2) gauge\ntheory with twisted boundary conditions. The curves interpolate smoothly\nbetween the perturbative semiclassicalresults and the Confinement regime. On\nthe basis of our results, we propose that the Confinement property might be\ncaused by a class of non-dilute multi-instanton configurations."
    },
    {
        "anchor": "Consistency between L\u00fcscher's finite volume method and HAL QCD method\n  for two-baryon systems in lattice QCD: There exist two methods to study two-baryon systems in lattice QCD: the\ndirect method which extracts eigenenergies from the plateaux of the temporal\ncorrelator and the HAL QCD method which extracts observables from the non-local\npotential associated with the tempo-spatial correlator. Although the two\nmethods should give the same results theoretically, qualitatively different\nresults have been reported. Recently, we pointed out that the separation of the\nground state from the excited states is crucial to obtain sensible results in\nthe former, while both states provide useful signals in the latter. In this\npaper, we identify the contribution of each state in the direct method by\ndecomposing the two-baryon correlators into the finite-volume eigenmodes\nobtained from the HAL QCD method. We consider the $\\Xi\\Xi$ system in the\n$^1$S$_0$ channel at $m_\\pi = 0.51$ GeV in 2+1 flavor lattice QCD using the\nwall and smeared quark sources. We demonstrate that the \"pseudo-plateau\" at\nearly time slices (t = 1~2 fm) from the smeared source in the direct method\nindeed originates from the contamination of the excited states, and the true\nplateau with the ground state saturation is realized only at t > 5~15 fm\ncorresponding to the inverse of the lowest excitation energy. We also\ndemonstrate that the two-baryon operator can be optimized by utilizing the\nfinite-volume eigenmodes, so that (i) the finite-volume energy spectra from the\nHAL QCD method agree with those from the optimized temporal correlator and (ii)\nthe correct spectra would be accessed in the direct method only if highly\noptimized operators are employed. Thus we conclude that the long-standing issue\non the consistency between the L\\\"uscher's finite volume method and the HAL QCD\nmethod for two baryons is now resolved: They are consistent with each other\nquantitatively only if the excited contamination is properly removed in the\nformer.",
        "positive": "Spectroscopy, Equation Of State And Monopole Percolation In Lattice QED\n  With Two Flavors: Non-compact lattice QED with two flavors of light dynamical quarks is\nsimulated on $16^4$ lattices, and the chiral condensate, monopole density and\nsusceptibility and the meson masses are measured. Data from relatively high\nstatistics runs at relatively small bare fermion masses of 0.005, 0.01, 0.02\nand 0.03 (lattice units) are presented. Three independent methods of data\nanalysis indicate that the critical point occurs at $\\beta =0.225(5)$ and that\nthe monopole condensation and chiral symmetry breaking transitions are\ncoincident. The monopole condensation data satisfies finite size scaling\nhypotheses with critical indices compatible with four dimensional percolation.\nThe best chiral equation of state fit produces critical exponents\n($\\delta=2.31$, $\\beta_{mag}=0.763$) which deviate significantly from mean\nfield expectations. Data for the ratio of the sigma to pion masses produces an\nestimate of the critical index $\\delta$ in good agreement with chiral\ncondensate measurements. In the strong coupling phase the ratio of the meson\nmasses are $M_\\sigma^2/M_\\rho^2\\approx 0.35$, $M_{A_1}^2/M_\\rho^2\\approx 1.4$\nand $M_\\pi^2/M_\\rho^2\\approx 0.0$, while on the weak coupling side of the\ntransition $M_\\pi^2/M_\\rho^2\\approx 1.0$, $M_{A_1}^2/M_\\rho^2\\approx 1.0$,\nindicating the restoration of chiral symmetry.\\footnote{$\\,^{}$}{August 1992}"
    },
    {
        "anchor": "Matrix elements of the plaquette operator of Lattice Gauge Theory: We show that in the spin-network basis it is possible to compute the matrix\nelements of any given operator of the Hamiltonian formulation of Lattice Gauge\nTheory (LGT). We give the explicit calculation for the case of the plaquette\noperator.",
        "positive": "The classically perfect fixed point action for SU(3) gauge theory: In this paper (the first of a series) we describe the construction of fixed\npoint actions for lattice $SU(3)$ pure gauge theory. Fixed point actions have\nscale invariant instanton solutions and the spectrum of their quadratic part is\nexact (they are classical perfect actions). We argue that the fixed point\naction is even 1--loop quantum perfect, i.e. in its physical predictions there\nare no $g^2 a^n$ cut--off effects for any $n$. We discuss the construction of\nfixed point operators and present examples. The lowest order $q {\\bar q}$\npotential $V(\\vec{r})$ obtained from the fixed point Polyakov loop correlator\nis free of any cut--off effects which go to zero as an inverse power of the\ndistance $r$."
    },
    {
        "anchor": "Heating and small-size instantons in the $O(3) \\:\u03c3$ model on the\n  lattice: We study the role of small-size instantons in the determination of the\ntopological susceptibility of the 2-d $O(3) \\: \\sigma $ model on the lattice.\nIn particular, we analyze how they affect the non-perturbative determination,\nby Monte Carlo techniques, of the renormalizations on the lattice. As a result,\nwe obtain a high-precision non-perturbative determination of the mixing with\nthe unity operator, finding good agreement with perturbative computations. We\nalso obtain the size distribution of instantons in the physical vacuum up to\nvery small values of the size in physical units, without observing any\nultraviolet cut-off. Moreover, we show by analytical calculation that the\nmixing of the topological susceptibility with the action density is a\nnegligible part of the whole non-perturbative signal.",
        "positive": "Hadronic light-by-light scattering amplitudes from lattice QCD versus\n  dispersive sum rules: The hadronic contribution to the eight forward amplitudes of light-by-light\nscattering ($\\gamma^*\\gamma^*\\to \\gamma^*\\gamma^*$) is computed in lattice QCD.\nVia dispersive sum rules, the amplitudes are compared to a model of the\n$\\gamma^*\\gamma^*\\to {\\rm hadrons}$ cross sections in which the fusion process\nis described by hadronic resonances. Our results thus provide an important test\nfor the model estimates of hadronic light-by-light scattering in the anomalous\nmagnetic moment of the muon, $a_\\mu^{\\rm HLbL}$. Using simple parametrizations\nof the resonance $M\\to \\gamma^*\\gamma^*$ transition form factors, we determine\nthe corresponding monopole and dipole masses by performing a global fit to all\neight amplitudes. Together with a previous dedicated calculation of the\n$\\pi^0\\to \\gamma^*\\gamma^*$ transition form factor, our calculation provides\nvaluable information for phenomenological estimates of $a_\\mu^{\\rm HLbL}$. The\npresented calculations are performed in two-flavor QCD with pion masses\nextending down to 190\\,MeV at two different lattice spacings. In addition to\nthe fully connected Wick contractions, on two lattice ensembles we also compute\nthe (2+2) disconnected class of diagrams, and find that their overall size is\ncompatible with a parameter-free, large-$N$ inspired prediction, where $N$ is\nthe number of colors. Motivated by this observation, we estimate in the same\nway the disconnected contribution to $a_\\mu^{\\rm HLbL}$."
    },
    {
        "anchor": "Chiral Lagrangians from lattice gauge theories in the strong coupling\n  limit: We derive nonlinear sigma models (chiral Lagrangians) over symmetric spaces\nU(n), U(2n)/Sp(2n), and U(2n)/O(2n) from U(N), O(N), and Sp(2N) lattice gauge\ntheories coupled to n flavors of staggered fermions, in the large-N and g^2 N\nlimit. To this end, we employ Zirnbauer's color-flavor transformation. We prove\nthe spatial homogeneity of the vacuum configurations of mesons by explicitly\nsolving the large-N saddle point equations, and thus establish the above\npatterns of spontaneous chiral symmetry breaking without any assumptions.",
        "positive": "Mirage in Temporal Correlation functions for Baryon-Baryon Interactions\n  in Lattice QCD: Single state saturation of the temporal correlation function is a key\ncondition to extract physical observables such as energies and matrix elements\nof hadrons from lattice QCD simulations. A method commonly employed to check\nthe saturation is to seek for a plateau of the observables for large Euclidean\ntime. Identifying the plateau in the cases having nearby states, however, is\nnon-trivial and one may even be misled by a fake plateau. Such a situation\ntakes place typically for the system with two or more baryons. In this study,\nwe demonstrate explicitly the danger from a possible fake plateau in the\ntemporal correlation functions mainly for two baryons ($\\Xi\\Xi$ and $NN$), and\nthree and four baryons ($^3{\\rm He}$ and $^4{\\rm He})$ as well, employing\n(2+1)-flavor lattice QCD at $m_{\\pi}=0.51$ GeV on four lattice volumes with\n$L=$ 2.9, 3.6, 4.3 and 5.8 fm. Caution is given for drawing conclusion on the\nbound $NN$, $3N$ and $4N$ systems only based on the temporal correlation\nfunctions."
    },
    {
        "anchor": "Closed k-strings in SU(N) gauge theories : 2+1 dimensions: We calculate the ground state energies of closed k-strings in\n(2+1)-dimensional SU(N) gauge theories, for N=4,5,6,8 and k=2,3,4. From the\ndependence of the ground state energy on the string length, we infer that such\nk-strings are described by an effective string theory that is in the same\nbosonic universality class (Nambu-Goto) as the fundamental string. When we\ncompare the continuum k-string tensions to the corresponding fundamental string\ntensions, we find that the ratios are close to, but typically 1-2 percent\nabove, the Casimir scaling values favoured by some theoretical approaches.\nFitting the N-dependence in a model-independent way favours an expansion in 1/N\n(as in Casimir scaling) rather than the 1/N^2 that is suggested by naive colour\ncounting. We also observe that the low-lying spectrum of k-string states falls\ninto sectors that belong to particular irreducible representations of SU(N),\ndemonstrating that the dynamics of string binding knows about the full gauge\ngroup and not just about its centre.",
        "positive": "The pion vector form factor from Lattice QCD at the physical point: We present an investigation of the electromagnetic pion form factor,\n$F_\\pi(Q^2)$, at small values of the four-momentum transfer $Q^2$ ($\\lesssim\n0.25$ GeV$^2$), based on the gauge configurations generated by European Twisted\nMass Collaboration with $N_f = 2$ twisted-mass quarks at maximal twist\nincluding a clover term. Momentum is injected using non-periodic boundary\nconditions and the calculations are carried out at a fixed lattice spacing ($a\n\\simeq 0.09$ fm) and with pion masses equal to its physical value, 240 MeV and\n340 MeV. Our data are successfully analyzed using Chiral Perturbation Theory at\nnext-to-leading order in the light-quark mass. For each pion mass two different\nlattice volumes are used to take care of finite size effects. Our final result\nfor the squared charge radius is $\\langle r^2 \\rangle_\\pi = 0.443~(29)$ fm$^2$,\nwhere the error includes several sources of systematic errors except the\nuncertainty related to discretization effects. The corresponding value of the\nSU(2) chiral low-energy constant $\\overline{\\ell}_6$ is equal to\n$\\overline{\\ell}_6 = 16.2 ~ (1.0)$."
    },
    {
        "anchor": "Updating algorithms with multi-step stochastic correction: Nested multi-step stochastic correction offers a possibility to improve\nupdating algorithms for numerical simulations of lattice gauge theories with\nfermions. The corresponding generalisations of the two-step multi-boson (TSMB)\nalgorithm as well as some applications with hybrid Monte Carlo (HMC) algorithms\nare considered.",
        "positive": "Semileptonic Decays of Heavy Mesons: A Status Report: We present intermediate results on our ongoing investigation concerning\nsemileptonic decays of heavy pseudoscalar mesons into pseudoscalar and vector\nmesons. The corresponding formfactors are evaluated at several momenta and\nappropriate combinations of four light and four heavy quarks, which are chosen\nto allow for an extrapolation into the B Meson region. In order to obtain clear\ngroundstate signals we apply gauge invariant ``Wuppertal'' smearing to the\nquarks. The analysis is based on 32 quenched gauge configurations of size $24^3\n\\times 64$ at $\\beta=6.3$, with Wilson fermions."
    },
    {
        "anchor": "Coupled-channel scattering in 1+1 dimensional lattice model: Based on the Lippmann-Schwinger equation approach, a generalized L\\\"uscher's\nformula in 1+1 dimensions for two particles scattering in both the elastic and\ncoupled-channel cases in moving frames is derived. A 2D coupled-channel\nscattering lattice model is presented, the model represents a\ntwo-coupled-channel resonant scattering scalars system. The Monte Carlo\nsimulation is performed on finite lattices and in various moving frames.\n  The 2D generalized L\\\"uscher's formula is used to extract the scattering\namplitudes for the coupled-channel system from the discrete finite-volume\nspectrum.",
        "positive": "Correlation functions between topological objects -- field theoretic\n  versus geometric definitions: We analyze topological objects in pure gluonic $SU(2)$ lattice gauge theory\nand compute correlation functions between instantons and monopoles. Concerning\nthe instantons we use geometric and field theoretic definitions of the\ntopological charge. On a $12^3\\times 4$ lattice it turns out that topological\nquantities have a non-trivial local correlation. The auto-correlation functions\nof the topological charge depend on cooling for both definitions. We fit the\ncorrelation functions to exponentials and obtain screening masses."
    },
    {
        "anchor": "Practical methods for a direct calculation of $\u0394I=1/2$ $K$ to\n  $\u03c0\u03c0$ Decay: A direct calculation of the complex $\\Delta I=1/2$ kaon decay amplitude is\nnotoriously difficult because of the presence of disconnected graphs. Here we\ndescribe and demonstrate two practical methods to defeat this problem: the\nEigCG algorithm and the use of time-separated $\\pi-\\pi$ sources. With a fine\ntuned EigCG implementation for domain wall fermions, the calculation of light\nquark propagators is accelerated by a factor of 5-10 on a variety of lattices\nfrom small ($16^3\\times32\\times16$) to large ($32^3\\times64\\times32$). In\naddition, a substantial reduction in noise is achieved by separating each of\nthe sources for the two pions in the time direction by 2-5 lattice spacings.\nThese methods are combined in a calculation of $K$ to $\\pi\\pi$ threshold decay\nusing a $24^3\\times64\\times16$ volume and 329 MeV pions. These methods result\nin non-zero signals for both Re($A_0$) and Im($A_0$) from 138 gauge\nconfigurations.",
        "positive": "First order transition regions in the quark masses and chemical\n  potential parameter space of QCD: We investigate the phase transitions of (2+Nf)-flavor QCD, where two light\nflavors and Nf massive flavors exist, aiming to understand the phase structure\nof (2+1)-flavor QCD. Performing simulations of 2-flavor QCD with improved\nstaggered and Wilson fermions and using the reweighting method, we calculate\nprobability distribution functions in the many-flavor QCD. Through the shape of\ndistribution functions, we determine the critical surface terminating first\norder phase transitions in the parameter space of the light quark mass, heavy\nquark mass and the chemical potential, and find that the first order region\nbecomes larger with Nf. We then study the critical surface at finite density\nfor large Nf and the first order region is found to become wider with the\nincreasing chemical potential. On the other hand, the light quark mass\ndependence of the critical mass of heavy quarks seems weak in the region we\ninvestigated. The result of this weak dependence suggests that the critical\nmass of heavy quark remains finite in the chiral limit of 2-flavors and there\nexists a second order transition region on the line of the 2-flavor massless\nlimit above the tri-critical point. Moreover, we extend the study of 2-flavor\nQCD at finite density to the case of a complex chemical potential and\ninvestigate the singularities where the partition function vanishes, so-called\nLee-Yang zeros. The plaquette effective potential is computed in the complex\nplane. We find that the shape of the effective potential changes from\nsingle-well on the real axis to double-well at large imaginary chemical\npotential and the double-well potential causes the singularities."
    },
    {
        "anchor": "Replica evolution of classical field in 4+1 dimensional spacetime toward\n  real time dynamics of quantum field: Real-time evolution of replicas of classical field is proposed as an\napproximate simulator of real-time quantum field dynamics at finite\ntemperatures. We consider $N$ classical field configurations dubbed as replicas\nwhich interact with each other via the $\\tau$-derivative terms and evolve with\nthe classical equation of motion. The partition function of replicas is found\nto be proportional to that of quantum field in the imaginary time formalism. As\nthe replica index $\\tau$ can be regarded as the imaginary time index, the\nreplica evolution is technically the same as the molecular dynamics part of the\nhybrid Monte-Carlo sampling and the replica configurations should reproduce the\ncorrect quantum equilibrium distribution after the long-time evolution. At the\nsame time, evolution of the replica-index average of field variables is\ndescribed by the classical equation of motion when the fluctuations are small.\nIn order to examine the real-time propagation properties of replicas, we first\ndiscuss replica evolution in quantum mechanics. Statistical averages of\nobservables are precisely obtained by the initial condition average of replica\nevolution, and the time evolution of the unequal-time correlation function,\n$\\langle x(t) x(t')\\rangle$, in a harmonic oscillator is also described well by\nthe replica evolution in the range $T/\\omega > 0.5$. Next, we examine the\nstatistical and dynamical properties of the $\\phi^4$ theory in the 4+1\ndimensional spacetime, which contains three spatial, one replica index or the\nimaginary time, and one real-time. We note that the Rayleigh-Jeans divergence\ncan be removed in replica evolution with $N \\geq 2$ when the mass counterterm\nis taken into account. We also find that the thermal mass obtained from the\nunequal-time correlation function at zero momentum grows as a function of the\ncoupling as in the perturbative estimate in the small coupling region.",
        "positive": "The infrared regime of SU(2) with one adjoint Dirac flavour: SU(2) gauge theory with one Dirac flavour in the adjoint representation is\ninvestigated on a lattice. Initial results for the gluonic and mesonic\nspectrum, static potential from Wilson and Polyakov loops, and the anomalous\ndimension of the fermionic condensate from the Dirac mode number are presented.\nThe results found are not consistent with conventional confining behaviour,\ninstead tentatively pointing towards a theory lying within or very near the\nonset of the conformal window, with the anomalous dimension of the fermionic\ncondensate in the range $0.9 \\lesssim \\gamma_* \\lesssim 0.95$. The implications\nof our work for building a viable theory of strongly interacting dynamics\nbeyond the standard model are discussed."
    },
    {
        "anchor": "Chiral crystals in strong-coupling lattice QCD at nonzero chemical\n  potential: We study the effective action for strong-coupling lattice QCD with\none-component staggered fermions in the case of nonzero chemical potential and\nzero temperature. The structure of this action suggests that at large chemical\npotentials its ground state is a crystalline `chiral density wave' that\nspontaneously breaks chiral symmetry and translation invariance. In mean-field\ntheory, on the other hand, we find that this state is unstable. We show that\nlattice artifacts are partly responsible for this, and suggest that if this\nphase exists in QCD, then finding it in Monte-Carlo simulations would require\nsimulating on relatively fine lattices. In particular, the baryon mass in\nlattice units, m_B, should be considerably smaller than its strong-coupling\nlimit of m_B~3.",
        "positive": "The high density region of QCD in a large mass and chemical potential\n  model: We study the high density region of QCD within an effective model obtained in\nthe frame of the hopping parameter expansion. The model still acknowledges the\nsign problem peculiar to non-zero chemical potential, but it permits the\ndevelopment of refined algorithms which ensure a good overlap of the Monte\nCarlo ensemble with the true one. We review the main features of the model,\nincluding the most explicit form of the resumed expansion, and present\ncalculations concerning the dependence of various observables on the chemical\npotential and on the temperature, in particular of the charge density and the\ndiquark susceptibility, which may be used to characterize the various phases\nexpected at high baryonic density."
    },
    {
        "anchor": "Static Friction Phenomena in Granular Materials: Coulomb Law vs.\n  Particle Geometry: The static as well as the dynamic behaviour of granular material are\ndetermined by dynamic {\\it and} static friction. There are well known methods\nto include static friction in molecular dynamics simulations using scarcely\nunderstood forces. We propose an Ansatz based on the geometrical shape of\nnonspherical particles which does not involve an explicit expression for static\nfriction. It is shown that the simulations based on this model are close to\nexperimental results.",
        "positive": "Magnetic catalysis in the (2+1)-dimensional Gross-Neveu model: We study the Gross-Neveu model in $2+1$ dimensions in an external magnetic\nfield $B$. We first summarize known mean-field results, obtained in the limit\nof large flavor number $N_\\mathrm{f}$, before presenting lattice results using\nthe overlap discretization to study one reducible fermion flavor,\n$N_\\mathrm{f}=1$. Our findings indicate that the magnetic catalysis phenomenon,\ni.e., an increase of the chiral condensate with the magnetic field, persists\nbeyond the mean-field limit for temperatures below the chiral phase transition\nand that the critical temperature grows with increasing magnetic field. This is\nin contrast to the situation in QCD, where the broken phase shrinks with\nincreasing $B$ while the condensate exhibits a non-monotonic $B$-dependence\nclose to the chiral crossover, and we comment on this discrepancy. We do not\nfind any trace of inhomogeneous phases induced by the magnetic field."
    },
    {
        "anchor": "Topological Susceptibility in Two Flavors Lattice QCD with the Optimal\n  Domain-Wall Fermion: We determine the topological susceptibility of the gauge configurations\ngenerated by lattice simulations using two flavors of optimal domain-wall\nfermion on the $ 16^3 \\times 32 $ lattice with length 16 in the fifth\ndimension, at the lattice spacing $ a \\simeq 0.1 $ fm. Using the adaptive\nthick-restart Lanczos algorithm, we project the low-lying eigenmodes of the\noverlap Dirac operator, and obtain the topological charge of each\nconfiguration, for eight ensembles with pion masses in the range $ 220-550 $\nMeV. From the topological charge, we compute the topological susceptibility and\nthe second normalized cumulant. Our result of the topological susceptibility\nagrees with the sea-quark mass dependence predicted by the chiral perturbation\ntheory and provides a determination of the chiral condensate,\n$\\Sigma^{\\bar{MS}}(2 GeV)=[259(6)(7) MeV]^3 $, and the pion decay constant\n$F_\\pi = 92(12)(2)$ MeV.",
        "positive": "Delta I=3/2 K to pi-pi decays with nearly physical kinematics: The \\Delta I = 3/2 K to pi pi decay amplitude is calculated on RBC/UKQCD 32^3\ntimes 64, L_s=32 dynamical lattices with 2+1 flavours of domain wall fermions\nusing the Dislocation Suppressing Determinant Ratio and Iwasaki gauge action.\nThe calculation is performed close to the physical pion mass (m_pi = 142.9(1.1)\nMeV and with a single lattice spacing (a^-1= 1.375(9) GeV.) We find Re(A_2) =\n(1.436 \\pm 0.063_{stat} \\pm 0.258_{syst}) times 10^-8 GeV and Im(A_2) = (-6.29\n\\pm 0.46_{stat} \\pm 1.20_{syst})\\times 10^{-13} GeV. These results are combined\nwith the experimental result for epsilon'/epsilon to predict Im(A_0) =\n-5.32(64)_{stat}(71)_{syst}\\times 10^{-11} GeV within the Standard Model. We\nalso perform a reweighting analysis to investigate the effects of partial\nquenching in the light-quark sector of our calculation. Following reweighting\nwe find Re(A_2) = (1.52\\pm 0.14_{stat}) \\times 10^-8 GeV and Im(A_2) = (-6.47\n\\pm 0.55_{stat})\\times 10^-13 GeV, which are consistent with our main results."
    },
    {
        "anchor": "Phase Diagram of Dynamical Twisted Mass Wilson Fermions at Finite\n  Isospin Chemical Potential: We consider the phase diagram of twisted mass Wilson fermions of two-flavor\nQCD in the parameter space of the quark mass, the isospin chemical potential,\nthe twist angle and the lattice spacing. This work extends earlier studies in\nthe continuum and those at zero chemical potential. We evaluate the phase\ndiagram as well as the spectrum of the (pseudo-)Goldstone bosons using the\nchiral Lagrangian for twisted mass Wilson fermions at non-zero isospin chemical\npotential. The phases are obtained from a mean field analysis. At zero twist\nangle we find that already an infinitesimal isospin chemical potential destroys\nthe Aoki phase. The reason is that in this phase we have massless Goldstone\nbosons with a non-zero isospin charge. At finite twist angle only two different\nphases are present, one phase which is continuously connected to the Bose\ncondensed phase at non-zero chemical potential and another phase which is\ncontinuously connected to the normal phase. For either zero or maximal twist\nthe phase diagram is more complicated as the saddle point equations allow for\nmore solutions.",
        "positive": "A Study of Symmetry Restoration at Finite Temperature in the O(4) Model\n  Using Anisotropic Lattices: Results of investigations of the O(4) spin model at finite temperature using\nanisotropic lattices are presented. In both the large $N$ approximation and the\nnumerical simulations using the Wolff cluster algorithm we find that the ratio\nof the symmetry restoration temperature $T_{\\rm SR}$ to the Higgs mass $m_{\\rm\nH}$ is independent of the anisotropy. We obtain a lower bound of $0.59 \\pm\n0.04$ for the ratio, $T_{\\rm SR}/m_{\\rm H}$, at $m_{\\rm H}a \\simeq 0.5$, which\nis lowered further by about 10% at $m_{\\rm H}a \\simeq 1.$"
    },
    {
        "anchor": "Confinement from Center Vortices: A review of old and new results: I briefly review the numerical evidence, some old and some quite recent, in\nfavor of the center vortex theory of confinement.",
        "positive": "Topological Charge Correlators, Spectral Bounds, and Contact Terms: The structure of topological charge fluctuations in the QCD vacuum is\nstrongly restricted by the spectral negativity of the Euclidean 2-point\ncorrelator for $x\\neq 0$ and the presence of a positive contact term. Some\nexamples are considered which illustrate the physical origin of these\nproperties."
    },
    {
        "anchor": "Spin-1 fields and RG flows in 4 dimensions: The most general local, classically scale invariant, perturbatively\nrenormalizable, globally $SU(N)$ invariant Lagrangian is constructed for spin-1\nfields in 4 dimensions. The total number of independent couplings is 7 and the\n1-loop $\\beta$-functions are computed in the MSbar scheme. A number of\nasymptotically free RG flows are identified corresponding to non-trivial QFTs.\nNone of these are gauge theories. The details of the large-$N$ limit are also\nworked out and it is shown that the RG phase space is qualitatively similar for\nall $N>5$ including the $N\\to\\infty$ limit.",
        "positive": "Curvature of the QCD critical line with 2+1 HISQ fermions: We present results on the curvature of the critical line of QCD with 2+1 HISQ\nfermions at nonzero temperature and quark density obtained by analytic\ncontinuation from imaginary chemical potentials. Monte Carlo simulations are\nperformed by means of the MILC code, suitably modified to include a nonzero\nimaginary baryon chemical potential. We set the chemical potential at the same\nvalue for the three quark species and work on the line of constant physics with\na light to strange mass ratio of 1/20 as determined in\nRef.~\\cite{Bazavov:2011nk}."
    },
    {
        "anchor": "Z_2 Monopoles and Deconfinement Phase Transition in SU(2) Lattice Gauge\n  Theory: The paper has been withdrawn",
        "positive": "Sphaleron rate from lattice QCD: We compute the sphaleron rate on the lattice from the inversion of the\nEuclidean time correlators of the topological charge density, performing also\ncontrolled continuum and zero-smoothing extrapolations. The correlator\ninversion is performed by means of a recently-proposed modification of the\nBackus-Gilbert method."
    },
    {
        "anchor": "Template Composite Dark Matter : SU(2) gauge theory with 2 fundamental\n  flavours: We present a non perturbative study of SU(2) gauge theory with two\nfundamental Dirac flavours. We discuss how the model can be used as a template\nfor composite Dark Matter (DM). We estimate one particular interaction of the\nDM candidate with the Standard Model : the interaction through photon exchange\ncomputing the electric polarizability of the DM candidate. Finally, we briefly\ndiscuss the viability of the model given the present experimental constraints.",
        "positive": "Scaling in a toy model of gluodynamics at finite temperatures: In the limit of $\\xi \\simeq a_\\sigma /a_\\tau \\to \\infty $ the gluodynamics\nwithout the magnetic part of action ($S_M\\sim 1/\\xi $) is considered as a\nself-contained model. The model is studied analytically in the continuum limit\non an extremely large lattice ($N_\\tau \\to \\infty $). Scaling conditions for\ncritical temperature and string tension are considered. The model shows trivial\n($g^2\\sim a_\\tau $) asymptotic freedom in the case of continuous gauge groups\nand nontrivial one ($g^2\\sim 1/\\ln 1/a_\\tau $) for discrete groups."
    },
    {
        "anchor": "Sextet QCD: slow running and the mass anomalous dimension: I report the results of Schroedinger functional calculations in the SU(3)\ngauge theory with two flavors of color sextet fermions, defined with the\nWilson-clover action using nHYP fat links. While we cannot confirm the infrared\nfixed point seen with thin links, we find very slow evolution of the coupling\nconstant, so slow that extraction of the mass anomalous dimension is\nstraightforward.",
        "positive": "Non-perturbative quark mass renormalization in quenched lattice QCD: The renormalization factor relating the bare to the renormalization group\ninvariant quark masses is accurately calculated in quenched lattice QCD using a\nrecursive finite-size technique. The result is presented in the form of a\nproduct of a universal factor times another factor, which depends on the\ndetails of the lattice theory but is easy to compute, since it does not involve\nany large scale differences. As a byproduct the Lambda-parameter of the theory\nis obtained with a total error of 8%."
    },
    {
        "anchor": "D- and B-Meson Semi-Leptonic Decays: Recent results for semi-leptonic decays of $D$ and $B$ mesons at $\\beta=6.4$,\nusing the Wilson action, and at $\\beta=6.0$, using the Clover action, are\nreported.",
        "positive": "Chiral property of domain-wall fermion from eigenvalues of 4D\n  Wilson-Dirac Operator: We investigate a chiral property of the domain-wall fermion (DWF) system\nusing the four-dimensional hermitian Wilson-Dirac operator $H_W$. A formula\nexpressing the Ward-Takahashi identity quark mass $m_{5q}$ with eigenvalues of\nthis operator is derived, which well explains the $N_5$ dependence of $m_{5q}$\nobserved in previous numerical simulations. We further discuss the chiral\nproperty of DWF in the large volume in terms of the spectra of $H_W$."
    },
    {
        "anchor": "Quark anti-quark expectation value in finite volume: We have computed the quark anti-quark expectation value in finite volume at\ntwo loop in chiral perturbation theory and compare it with a formula obtained\nin analogy to the Luscher formula for pion mass in finite volume. We observe\nthat due to the small finite size correction at two loop it is not possible to\nobtain conclusions on the accuracy of the extended Luscher formula.",
        "positive": "Window contributions to the muon hadronic vacuum polarization with\n  twisted-mass fermions: We present a lattice calculation of the Euclidean position-space windows\ncontributing to the leading-order hadronic vacuum polarization term of the muon\nanomalous magnetic moment $a_\\mu$. Short-, intermediate- and long-distance\nwindows are considered in order to isolate different scales sensitive to\nspecific integration ranges of experimental time-like data used in the R-ratio.\nBy adopting the same smooth window function introduced by the RBC and UKQCD\nCollaborations with width parameter $\\Delta = 0.15~\\rm fm$, for the\nisospin-symmetric, light, quark-connected component we get $a_\\mu^{\\rm SD} (ud)\n= 48.21\\,(80) \\cdot 10^{-10}$ , $a_\\mu^{\\rm W} (ud) = 202.2\\,(2.6) \\cdot\n10^{-10}$ and $a_\\mu^{\\rm LD} (ud) = 382.5\\,(11.7) \\cdot 10^{-10}$ in the\nshort- (SD), intermediate- (W) and long-distance (LD) time regions,\nrespectively, with $t_0 = 0.4~\\rm fm$ and $t_1 = 1.0~\\rm fm$. Our results are\nobtained using the gauge configurations generated by the Extended Twisted Mass\nCollaboration with $N_f=2+1+1$ dynamical quarks, at three values of the lattice\nspacing varying from 0.089 to 0.062 fm, at several lattice volumes and with\npion masses in the range $M_\\pi \\simeq 220 - 490~\\rm MeV$."
    },
    {
        "anchor": "On observable particles in theories with a Brout-Englert-Higgs effect: Even at weak coupling the physical, observable spectrum of gauge theories\nwith a Brout-Englert-Higgs effect can deviate from the elementary one of\nperturbation theory. This can be analytically described and treated using the\nFr\\\"ohlich-Morchio-Strocchi mechanism. We confirm this by lattice simulation\nfor an SU(3) gauge theory with a fundamental scalar, a toy model for grand\nunification. We also show that this has experimentally observable consequence,\ne.g., in scattering cross-sections of lepton collisions in this toy model.",
        "positive": "Radiative transitions of doubly charmed baryons in lattice QCD: We evaluate the spin-$3/2 \\to$ spin-$1/2$ electromagnetic transitions of the\ndoubly charmed baryons on 2+1 flavor, $32^3 \\times 64$ PACS-CS lattices with a\npion mass of $156(9)$ MeV/c$^2$. A relativistic heavy quark action is employed\nto minimize the associated systematic errors on charm-quark observables. We\nextract the magnetic dipole, $M1$, and the electric quadrupole, $E2$,\ntransition form factors. In order to make a reliable estimate of the $M1$ form\nfactor, we carry out an analysis by including the effect of excited-state\ncontributions. We find that the $M1$ transition is dominant and light degrees\nof freedom ($u/d$- or $s$-quark) play the leading role. $E2$ form factors, on\nthe other hand, are found to be negligibly small, which in turn, have minimal\neffect on the helicity and transition amplitudes. We predict the decay widths\nand lifetimes of $\\Xi_{cc}^{\\ast +,++}$ and $\\Omega_{cc}^{\\ast +}$ based on our\nresults. Finite size effects on these ensembles are expected to be around 1\\%.\nDifferences in kinematical and dynamical factors with respect to the\n$N\\gamma\\to\\Delta$ transition are discussed and compared to non-lattice\ndeterminations as well keeping possible systematic artifacts in mind. A\ncomparison to $\\Omega_c \\gamma \\rightarrow \\Omega_c^\\ast$ transition and a\ndiscussion on systematic errors related to the choice of heavy quark action are\nalso given. Results we present here are particularly suggestive for\nexperimental facilities such as LHCb, PANDA, Belle II and BESIII to search for\nfurther states."
    },
    {
        "anchor": "Strongly Coupled QCD at Finite Baryon Density: The analytical results obtained in the infinite mass and strong coupling\nlimits of QCD are difficult to reconcile with the predictions of the Monomer\nDimer Polymer algorithm. We have reconsidered in detail the results obtained\nwith this simulation scheme and evidences of severe convergence problems are\npresented for the SU(3) and SU(2) gauge group.",
        "positive": "Monte Carlo simulation of systems with complex-valued measures: A simulation method based on the RG blocking is shown to yield statistical\nerrors smaller than that of the crude MC using absolute values of the original\nmeasures. The new method is particularly suitable to apply to the sign problem\nof indefinite or complex-valued measures. We demonstrate the many advantages of\nthis method in the simulation of 2D Ising model with complex-valued\ntemperature."
    },
    {
        "anchor": "A Quantum Perfect Lattice Action for Monopoles and Strings: A quantum perfect lattice action in four dimensions can be derived\nanalytically as a renormalized trajectory when we perform a block spin\ntransformation of monopole currents in a simple but non-trivial case of\nquadratic monopole interactions. The spectrum of the lattice theory is\nidentical to that of the continuum theory. The perfect monopole action is\ntransformed exactly into a lattice action of a string model. A perfect operator\nevaluating a static potential between electric charges is also derived\nexplicitly. If the monopole interactions are weak as in the case of infrared\nSU(2) QCD, the string interactions become strong. The static potential and the\nstring tension is estimated analytically by the use of the strong coupling\nexpansion and the continuum rotational invariance is restored completely.",
        "positive": "On the Spectrum of Lattice Dirac Operators: With the Schwinger model as example I discuss properties of lattice Dirac\noperators, with some emphasis on Monte Carlo results for topological charge,\nchiral fermions and eigenvalue spectra."
    },
    {
        "anchor": "Matter near to the Endpoint of the Electroweak Phase Transition: Wave functions and the screening mass spectrum in the 3D SU(2)-Higgs model\nnear to the phase transition line below the endpoint and in the crossover\nregion are calculated. In the crossover region the changing spectrum versus\ntemperature is examined showing the aftermath of the phase transition at lower\nHiggs mass. Large sets of operators with various extensions are used allowing\nto identify wave functions in position space.",
        "positive": "Variance reduction with practical all-to-all lattice propagators: We discuss all-to-all quark propagator techniques in two (related) contexts\nwithin Lattice QCD: the computation of closed quark propagators, and\napplications to the so-called \"eye diagrams\" appearing in the computation of\nnon-leptonic kaon decay amplitudes. Combinations of low-mode averaging and\ndiluted stochastic volume sources that yield optimal signal-to-noise ratios for\nthe latter problem are developed. We also apply a recently proposed probing\nalgorithm to compute directly the diagonal of the inverse Dirac operator, and\ncompare its performance with that of stochastic methods. At fixed computational\ncost the two procedures yield comparable signal-to-noise ratios, but probing\nhas practical advantages which make it a promising tool for a wide range of\napplications in Lattice QCD."
    },
    {
        "anchor": "Mixed Action Lattice Spacing Effects on the Nucleon Axial Charge: We study the nucleon axial charge in the chiral perturbation theory for a\nmixed lattice action of Ginsparg-Wilson valence quarks and staggered sea\nquarks. In particular, we investigate the lattice spacing $a^2$-dependence of\nthe neutron to proton axial transition matrix element. By using the known\nlow-energy constants (LEC's) and an estimated value of a new LEC which appears\nin the calculation, we see a large lattice spacing effect on $g_A$.",
        "positive": "Landau gauge gluon and ghost propagators from lattice QCD with Nf=2\n  twisted mass fermions at finite temperature: We investigate the temperature dependence of the Landau gauge gluon and ghost\npropagators in lattice QCD with two flavors of maximally twisted mass fermions.\nFor these propagators we provide and analyze data which corresponds to pion\nmass values between 300 and 500 MeV. For the gluon propagator we find that both\nthe longitudinal and transversal component change smoothly in the crossover\nregion, while the ghost propagator exhibits only a very weak temperature\ndependence. For momenta between 0.4 and 3.0 GeV we give a parametrization for\nour lattice data. It may serve as input to studies which employ continuum\nfunctional methods."
    },
    {
        "anchor": "Absence of evidence for pentaquarks on the lattice: We study the question of whether or not QCD predicts a pentaquark state. We\nuse the improved, fixed point lattice QCD action which has very little\nsensitivity to the lattice spacing and also allows us to reach light quark\nmasses. The analysis was performed on a single volume of size $(1.8 {\\rm\nfm})^3\\times 3.6 {\\rm fm}$ with lattice spacing of $a=0.102$ fm. We use the\ncorrelation matrix method to identify the ground and excited states in the\nisospin 0, negative parity channel. In the quenched approximation where\ndynamical quark effects are omitted, we do not find any evidence for a\npentaquark resonance in QCD.",
        "positive": "Precision computation of the strange quark's mass in quenched QCD: We determine the renormalization group invariant quark mass corresponding to\nthe sum of the strange and the average light quark mass in the quenched\napproximation of QCD, using as essential input the mass of the K-mesons. In the\ncontinuum limit we find $(M_s + M_{light})/F_K=0.874(29)$, which includes\nsystematic errors. Translating this non-perturbative result into the running\nquark masses in the $\\msbar$-scheme at $\\mu=2 GeV$ and using the quark mass\nratios from chiral perturbation theory, we obtain $\\mbar_s(2 GeV)=97(4) MeV$.\nWith the help of recent results by the CP-PACS Collaboration, we estimate that\na 10% higher value would be obtained if one replaced $F_K$ by the nucleon mass\nto set the scale. This is a typical ambiguity in the quenched approximation."
    },
    {
        "anchor": "Partial wave decomposition on the lattice and its applications to the\n  HAL QCD method: The approximated partial wave decomposition method to the discrete data on a\ncubic lattice, developed by C. W. Misner, is applied to the calculation of\n$S$-wave hadron-hadron scatterings by the HAL QCD method in lattice QCD. We\nconsider the Nambu-Bethe-Salpeter (NBS) wave function for the spin-singlet\n$\\Lambda_c N$ system calculated in the $(2+1)$-flavor QCD on a\n$(32a~\\mathrm{fm})^3$ lattice at the lattice spacing $a\\simeq0.0907$ fm and\n$m_\\pi \\simeq 700$ MeV. We find that the $l=0$ component can be successfully\nextracted by Misner's method from the NBS wave function projected to $A_1^+$\nrepresentation of the cubic group, which contains small $l\\ge 4$ components.\nFurthermore, while the higher partial wave components are enhanced so as to\nproduce significant comb-like structures in the conventional HAL QCD potential\nif the Laplacian approximated by the usual second order difference is applied\nto the NBS wave function, such structures are found to be absent in the\npotential extracted by Misner's method, where the Laplacian can be evaluated\nanalytically for each partial wave component. Despite the difference in the\npotentials, two methods give almost identical results on the central values and\non the magnitude of statistical errors for the fits of the potentials, and\nconsequently on the scattering phase shifts. This indicates not only that\nMisner's method works well in lattice QCD with the HAL QCD method but also that\nthe contaminations from higher partial waves in the study of $S$-wave\nscatterings are well under control even in the conventional HAL QCD method. It\nwill be of interest to study interactions in higher partial wave channels in\nthe HAL QCD method with Misner's decomposition, where the utility of this new\ntechnique may become clearer.",
        "positive": "Algorithms for Lattice QCD with Dynamical Fermions: We consider recent progress in algorithms for generating gauge field\nconfigurations that include the dynamical effects of light fermions. We survey\nwhat has been achieved in recent state-of-the-art computations, and examine the\ntrade-offs between performance and control of systematic errors. We briefly\nreview the use of polynomial and rational approximations in Hybrid Monte Carlo\nalgorithms, and some of the theory of on-shell chiral fermions on the lattice.\nThis provides a theoretical framework within which we compare algorithmic\nalternatives for their implementation; and again we examine the trade-offs\nbetween speed and error control."
    },
    {
        "anchor": "Axial U(1) symmetry near the pseudocritical temperature in $N_f=2+1$\n  lattice QCD with chiral fermions: We study the $U(1)_A$ anomaly at high temperatures of $N_f=2+1$ lattice QCD\nwith chiral fermions. Gauge ensembles are generated with M\\\"obius domain-wall\n(MDW) fermions, and the measurements are reweighted to those with overlap\nfermions. We report on the results for the Dirac spectra, the $U(1)_A$\nsusceptibility, and the topological susceptibility in the temperature range of\n$T=136$, $153$, $175$, and $204$ MeV, where the up and down quark masses are\nset to be near the physical point as well as at lighter or heavier masses.",
        "positive": "The Running Coupling from Lattice Gauge Theory: From an accurate determination of the inter-quark potential, one can study\nthe running coupling constant for a range of $R$-values and hence estimate the\nscale $\\Lambda_{\\msbar} $. Detailed results are presented for $SU(2)$ pure\ngauge theory to illustrate the method."
    },
    {
        "anchor": "Proof of the renormalizability of the gradient flow: We give an alternative perturbative proof of the renormalizability of the\nsystem defined by the gradient flow and the fermion flow in vector-like gauge\ntheories.",
        "positive": "Topological properties of the SU(3) random vortex world-surface model: The random vortex world-surface model is an infrared effective model of\nYang-Mills dynamics based on center vortex degrees of freedom. These degrees of\nfreedom carry topological charge through writhe and self-intersection of their\nworld-surfaces. A practical implementation of the model realizes the vortex\nworld-surfaces by composing them of elementary squares on a hypercubic lattice.\nThe topological charge for specifically such configurations is constructed in\nthe case of SU(3) color. This necessitates a proper treatment of vortex color\nstructure at vortex branchings, a feature which is absent in the SU(2) color\ncase investigated previously. On the basis of the construction, the topological\nsusceptibility is evaluated in the random vortex world-surface ensemble, both\nin the confined low-temperature as well as in the deconfined high-temperature\nphase."
    },
    {
        "anchor": "Charm and strange hadron spectra from overlap fermions on HISQ gauge\n  configurations: We report here results on charm and strange hadron spectra.\n  Adopting a mixed action approach, we use overlap fermions for valence quarks,\non a background of 2+1+1 flavours HISQ gauge configurations of MILC\ncollaboration. Two lattice spacings (0.09 fm and 0.06 fm) are used. We find the\nhyperfine splitting of 1S charmonia to be 114(3)(-2) MeV and 109(4)(-3) MeV,\nand the splitting (m(Omega_ccc)-3/2 m(J\\Psi)) is found to be 110(20)(-10) MeV\nand 120(10) MeV, corresponding to lattices with spacings a = 0.09 and 0.06 fm\nrespectively. We also look at the ratio of the leptonic decay constant\nf_Ds*/f_Ds.",
        "positive": "Photon production rate from Transverse-Longitudinal ($T-L$) mesonic\n  correlator on the lattice: Thermal photons from the QGP provide important information about the\ninteraction among plasma constituents. The photon production rate from a\nthermally equilibrated system is proportional to the transverse spectral\nfunction $\\rho_T(\\omega=|\\vec k|, \\vec k)$. One can also calculate the photon\nproduction rate from the difference between $\\rho_T(\\omega,\\vec k)$\n(transverse) and $\\rho_L(\\omega,\\vec k)$ (longitudinal) projections, as\n$\\rho_L$ vanishes on the photon point. Because the UV part of $\\rho_T-\\rho_L$\nis suppressed, the corresponding Euclidean correlator receives most of its\ncontribution from the IR part. We calculate the $T\\!-\\!L$ correlator on\n$N_f=2+1$ flavour HISQ configurations with $m_l=m_s/5$ at temperature of about\n$1.15\\,T_{pc}$ (220 MeV). We have used two ans\\\"{a}tze for the spectral\nfunction: 1) A polynomial connected to the UV region consistent with OPE\nexpansion and 2) a hydro-inspired spectral function. We have also applied the\nBackus-Gilbert method to estimate the spectral function. All these different\napproaches are combined to estimate the photon production rate."
    },
    {
        "anchor": "Estimating the thermal photon production rate using lattice QCD: We present results for the photon emission rate determined from the\ntransverse channel vector correlator at fixed spatial momentum using two\nflavors of dynamical Wilson fermions at $T\\sim$250 MeV. We estimate the\ntransverse channel spectral function using the continuum extrapolated\ncorrelator by applying various fit ans\\\"atze with a smooth matching to the NLO\nperturbative result. We confront our estimate based on this channel with the\nlatest results of our collaboration based on the difference of the transverse\nand longitudinal channels.",
        "positive": "Isospin breaking in octet baryon mass splittings: Using an SU(3) flavour symmetry breaking expansion in the quark mass, we\ndetermine the QCD component of the nucleon, Sigma and Xi mass splittings of the\nbaryon octet due to up-down (and strange) quark mass differences in terms of\nthe kaon mass splitting. Provided the average quark mass is kept constant, the\nexpansion coefficients in our procedure can be determined from computationally\ncheaper simulations with mass degenerate sea quarks and partially quenched\nvalence quarks. Both the linear and quadratic terms in the SU(3) flavour\nsymmetry breaking expansion are considered; it is found that the quadratic\nterms only change the result by a few percent, indicating that the expansion is\nhighly convergent."
    },
    {
        "anchor": "One-loop renormalization of staple-shaped operators in continuum and\n  lattice regularizations: In this paper we present one-loop results for the renormalization of nonlocal\nquark bilinear operators, containing a staple-shaped Wilson line, in both\ncontinuum and lattice regularizations. The continuum calculations were\nperformed in dimensional regularization, and the lattice calculations for the\nWilson/clover fermion action and for a variety of Symanzik-improved gauge\nactions. We extract the strength of the one-loop linear and logarithmic\ndivergences (including cusp divergences), which appear in such nonlocal\noperators; we identify the mixing pairs which occur among some of these\noperators on the lattice, and we calculate the corresponding mixing\ncoefficients. We also provide the appropriate RI'-like scheme, which\ndisentangles this mixing nonperturbatively from lattice simulation data, as\nwell as the one-loop expressions of the conversion factors, which turn the\nlattice data to the MS-bar scheme. Our results can be immediately used for\nimproving recent nonperturbative investigations of transverse\nmomentum-dependent distribution functions (TMDs) on the lattice. Finally,\nextending our perturbative study to general Wilson-line lattice operators with\nn cusps, we present results for their renormalization factors, including\nidentification of mixing and determination of the corresponding mixing\ncoefficients, based on our results for the staple operators.",
        "positive": "The chiral phase transition for QCD with sextet quarks: QCD with 2 massless colour-sextet quarks is studied as a model of Walking\nTechnicolor. We simulate lattice QCD with 2 light color-sextet staggered quarks\nat finite temperature, and use the dependence of the coupling at the chiral\ntransition on the temporal extent, $N_t$, of the lattice in lattice units to\nstudy the running of the bare lattice coupling with lattice spacing. Our goal\nis to determine whether this theory is QCD-like and `walks', or if it is\nconformal. If it is QCD-like, the coupling at the chiral transition should tend\nto zero as $N_t \\rightarrow \\infty$ in a manner controlled by asymptotic\nfreedom, i.e. by the perturbative $\\beta$-function. On the other hand, if this\ntheory is conformal, this coupling will approach a non-zero limit in the $N_t\n\\rightarrow \\infty$ limit. We are extending our simulations on an $N_t=8$\nlattice to determine the position of the chiral transition with greater\naccuracy, and are performing simulations on an $N_t=12$ lattice."
    },
    {
        "anchor": "$b\\bar b u\\bar d$ four-quark systems in the Born-Oppenheimer\n  approximation: prospects and challenges: We summarize previous work on $\\bar b \\bar bud$ four-quark systems in the\nBorn-Oppenheimer approximation and discuss first steps towards an extension to\nthe theoretically more challenging $b\\bar b u\\bar d$ system. Strategies to\nidentify a possibly existing $b\\bar b u\\bar d$ bound state are discussed and\nfirst numerical results are presented.",
        "positive": "$u d \\bar{b} \\bar{b}$ tetraquark resonances with lattice QCD potentials\n  and the Born-Oppenheimer approximation: We study tetraquark resonances with lattice QCD potentials computed for a\nstatic bbar bbar pair in the presence of two lighter quarks u d, the\nBorn-Oppenheimer approximation and the emergent wave method. As a proof of\nconcept we focus on the system with isospin I = 0, but consider different\nrelative angular momenta l of the heavy quarks bbar bbar. For l=0 a bound state\nhas already been predicted with quantum numbers I(JP) = 0(1+). Exploring\nvarious angular momenta we now compute the phase shifts and search for S and T\nmatrix poles in the second Riemann sheet. We predict a tetraquark resonance for\nl =1, decaying into two B mesons, with quantum numbers I(JP) = 0(1-), mass m =\n10 \\, 576^{+4}_{-4} MeV} and decay width Gamma = 112^{+90}_{-103} MeV."
    },
    {
        "anchor": "Iterative methods for overlap and twisted mass fermions: We present a comparison of a number of iterative solvers of linear systems of\nequations for obtaining the fermion propagator in lattice QCD. In particular,\nwe consider chirally invariant overlap and chirally improved Wilson (maximally)\ntwisted mass fermions. The comparison of both formulations of lattice QCD is\nperformed at four fixed values of the pion mass between 230MeV and 720MeV. For\noverlap fermions we address adaptive precision and low mode preconditioning\nwhile for twisted mass fermions we discuss even/odd preconditioning. Taking the\nbest available algorithms in each case we find that calculations with the\noverlap operator are by a factor of 30-120 more expensive than with the twisted\nmass operator.",
        "positive": "Parallelizing the QUDA Library for Multi-GPU Calculations in Lattice\n  Quantum Chromodynamics: Graphics Processing Units (GPUs) are having a transformational effect on\nnumerical lattice quantum chromodynamics (LQCD) calculations of importance in\nnuclear and particle physics. The QUDA library provides a package of mixed\nprecision sparse matrix linear solvers for LQCD applications, supporting single\nGPUs based on NVIDIA's Compute Unified Device Architecture (CUDA). This\nlibrary, interfaced to the QDP++/Chroma framework for LQCD calculations, is\ncurrently in production use on the \"9g\" cluster at the Jefferson Laboratory,\nenabling unprecedented price/performance for a range of problems in LQCD.\nNevertheless, memory constraints on current GPU devices limit the problem sizes\nthat can be tackled. In this contribution we describe the parallelization of\nthe QUDA library onto multiple GPUs using MPI, including strategies for the\noverlapping of communication and computation. We report on both weak and strong\nscaling for up to 32 GPUs interconnected by InfiniBand, on which we sustain in\nexcess of 4 Tflops."
    },
    {
        "anchor": "Transverse momentum distributions of quarks in the nucleon from Lattice\n  QCD: Transverse momentum dependent parton distribution functions (TMDPDFs) encode\ninformation about the intrinsic motion of quarks inside the nucleon. They are\nimportant non-perturbative ingredients in our understanding of, e.g., azimuthal\nasymmetries and other qualitative features in semi-inclusive deep inelastic\nscattering experiments. We present first calculations on the lattice, based on\nMILC gauge configurations and propagators from LHPC. They yield polarized and\nunpolarized transverse momentum dependent quark densities and enable us to test\nthe assumption of factorization in x and transverse momentum. The operators we\nemploy are non-local and contain a Wilson line, whose renormalization requires\nthe removal of a divergence linear in the cutoff 1/a.",
        "positive": "Quantum Spin Formulation of the Principal Chiral Model: We formulate the two-dimensional principal chiral model as a quantum spin\nmodel, replacing the classical fields by quantum operators acting in a Hilbert\nspace, and introducing an additional, Euclidean time dimension. Using coherent\nstate path integral techniques, we show that in the limit in which a large\nrepresentation is chosen for the operators, the low energy excitations of the\nmodel describe a principal chiral model in three dimensions. By dimensional\nreduction, the two-dimensional principal chiral model of classical fields is\nrecovered."
    },
    {
        "anchor": "Precise Determination of the Charm Quark Mass: The determination of the charm quark mass is now possible to 1% from QCD,\nwith lattice QCD pushing the error down below 1%. I will describe the\ningredients of this approach and how it can achieve this accuracy. Results for\nquark mass ratios, m_c/m_s and m_b/m_c, can also be determined to 1% from\nlattice QCD, allowing accuracy for the heavy quark masses to be leveraged into\nthe light quark sector. I will discuss the prospects for, and importance of,\nimproving results in future calculations.",
        "positive": "Visualisation of Centre Vortex Structure: The centre vortex structure of the $SU(3)$ gauge field vacuum is explored\nthrough the use of novel visualisation techniques. The lattice is partitioned\ninto 3D time slices, and vortices are identified by locating plaquettes with\nnontrivial centre phases. Vortices are illustrated by rendering vortex lines\nthat pierce these nontrivial plaquettes. Nontrivial plaquettes with one\ndimension in the suppressed time direction are rendered by identifying the\nvisible spatial link. These visualisations highlight the frequent presence of\nsingular points and reveal an important role for branching points in $SU(3)$\ngauge theory in creating high topological charge density regimes.\nVisualisations of the topological charge density are presented, and an\ninvestigation into the correlation between vortex structures and topological\ncharge density is conducted. The results provide new insight into the\nmechanisms by which centre vortices generate nontrivial gauge field topology.\nThis work demonstrates the utility of visualisations in conducting centre\nvortex studies, presenting new avenues with which to investigate this\nperspective of the QCD vacuum."
    },
    {
        "anchor": "Competing order in the fermionic Hubbard model on the hexagonal graphene\n  lattice: We study the phase diagram of the fermionic Hubbard model on the hexagonal\nlattice in the space of on-site and nearest neighbor couplings with\nHybrid-Monte-Carlo simulations. With pure on-site repulsion this allows to\ndetermine the critical coupling strength for spin-density wave formation with\nthe standard approach of introducing a small mass term, explicitly breaking the\nsublattice symmetry. The analogous mass term for charge-density wave formation\nabove a critical nearest-neighbor repulsion, on the other hand, would introduce\na fermion sign problem. The competition between the two and the phase diagram\nin the space of the two coouplings can however be studied in simulations\nwithout explicit sublattice symmetry breaking. Our results compare\nqualitatively well with the Hartree-Fock phase diagram. We furthermore\ndemonstrate how spin-symmetry breaking by the Euclidean time discretization can\nbe avoided also, when using an improved fermion action based on an exponetial\ntransfer matrix with exact sublattice symmetry.",
        "positive": "Gradient Flow Coupling in the SU(2) gauge theory with two adjoint\n  fermions: We study SU(2) gauge theory with two fermion flavors in the adjoint\nrepresentation. Using a clover improved HEX smeared action and the gradient\nflow running coupling allows us to simulate with larger lattice size than\nbefore. We find an infrared fixed point after a continuum extrapolation in the\nrange $4.5 \\lesssim g^{*2} \\lesssim 5$. We also measure the mass anomalous\ndimension and find the value $ 0.25 \\lesssim \\gamma^* \\lesssim 0.28 $ at the\nfixed point."
    },
    {
        "anchor": "Stability of complex Langevin dynamics in effective models: The sign problem at nonzero chemical potential prohibits the use of\nimportance sampling in lattice simulations. Since complex Langevin dynamics\ndoes not rely on importance sampling, it provides a potential solution.\nRecently it was shown that complex Langevin dynamics fails in the disordered\nphase in the case of the three-dimensional XY model, while it appears to work\nin the entire phase diagram in the case of the three-dimensional SU(3) spin\nmodel. Here we analyse this difference and argue that it is due to the presence\nof the nontrivial Haar measure in the SU(3) case, which has a stabilizing\neffect on the complexified dynamics. The freedom to modify and stabilize the\ncomplex Langevin process is discussed in some detail.",
        "positive": "$K_L$ - $K_S$ mass difference computed with a 171 MeV pion mass: In this work, we used a $32^3 \\times 64 \\times 32$, 2+1 flavor domain wall\nlattice with Iwasaki+DSDR gauge action. The pion mass is 171 MeV and the kaon\nmass is 492 MeV. We implement the Glashow-Iliopoulos-Maiani (GIM) cancellation\nusing charm quark masses of 750 MeV and 592 MeV. This is an intermediate\ncalculation, in that we are using both a coarse lattice spacing (1/a = 1.37GeV)\nso we expect significant discretization error coming from charm quark mass and\nwe are also using unphysical kinematics for the pion. The main purpose of this\ncalculation is to study the contribution from the two-pion intermediate state\nwhen the energy of a two-pion state is lower than that of the kaon, as well as\nthe corresponding finite volume correction to the $\\Delta M_K$."
    },
    {
        "anchor": "Effects of Chemical Potential on Hadron Masses at Finite Temperature: We study the effects of the chemical potential on the $\\rho$ meson mass at\nfinite temperature. Our preliminary results show that some effects are seen in\nthe vicinity of the phase transition point. Although the signal is still too\nnoisy to obtain conclusive physical results within limited statistics, the mass\nsusceptibility is consistent with zero.",
        "positive": "BB Potentials in Quenched Lattice QCD: The potentials between two B-mesons are computed in the heavy-quark limit\nusing quenched lattice QCD at $m_\\pi\\sim 400~{\\rm MeV}$. Non-zero central\npotentials are clearly evident in all four spin-isospin channels, (I,s_l) =\n(0,0) , (0,1) , (1,0) , (1,1), where s_l is the total spin of the light degrees\nof freedom. At short distance, we find repulsion in the $I\\ne s_l$ channels and\nattraction in the I=s_l channels. Linear combinations of these potentials that\nhave well-defined spin and isospin in the t-channel are found, in three of the\nfour cases, to have substantially smaller uncertainties than the potentials\ndefined with the s-channel (I,s_l), and allow quenching artifacts from single\nhairpin exchange to be isolated. The BB*\\pi coupling extracted from the\nlong-distance behavior of the finite-volume t-channel potential is found to be\nconsistent with quenched calculations of the matrix element of the isovector\naxial-current. The tensor potentials in both of the s_l = 1 channels are found\nto be consistent with zero within calculational uncertainties."
    },
    {
        "anchor": "Update on Quarkonium Spectroscopy and $\u03b1_{strong}$ from NRQCD: NRQCD results for Upsilon and Charmonium using both dynamical and quenched\nconfigurations are presented. We investigate dependence on the light dynamical\nquark mass. Preliminary dynamical ($n_f = 2$) Charmonium data are combined with\nquenched results to extract the strong coupling constant $\\alpha_P^{(n_f)}$ for\nthe physical number of light dynamical quarks, $n_f = 3$. Good agreement is\nfound with calculations based on the Upsilon system. We show that a discrepancy\nin $\\alpha_P^{(n_f=0)}$, found between the Upsilon and Charmonium systems in\nthe quenched theory, disappears upon extrapolating to the physical number of\nflavors. Results for the strong coupling constant $\\alpha_{\\overline{MS}}$ are\npresented and sources of systematic error investigated.",
        "positive": "Static force from the lattice: We present a novel approach to compute the force between a static quark and a\nstatic antiquark from lattice gauge theory directly, rather than extracting it\nfrom the static energy. We explore this approach for SU(3) pure gauge theory\nusing the multilevel algorithm and smeared operators."
    },
    {
        "anchor": "Tetraquark channels with $\\bar b b$ pair in the static limit: Belle experiment discovered two hadrons with exotic quark content\n$Z_b^+\\simeq \\bar bb \\bar du$. We present a lattice study of the $\\bar bb\\bar\ndu$ systems with various quantum numbers using static bottom quarks. Only one\nset of quantum numbers that couples to $Z_b$ and $\\Upsilon\\;\\pi$ was explored\non the lattice before: these studies found an attractive potential between $B$\nand $\\bar B^*$ which leads to a bound state below the threshold. In the present\nstudy, we consider the other three sets of quantum numbers. Eigen-energies of\nthe $\\bar bb \\bar du$ system are extracted as a function of separation between\n$b$ and $\\bar b$. The resulting eigen-energies do not show any sizable\ndeviation from non-interacting energies of the systems $\\bar bb+\\bar du$ and\n$\\bar bu+\\bar db$, so no significant attraction or repulsion is found. A slight\nexception is a small attraction between $B$ and $\\bar B^*$ at small distance\nfor the quantum number that couples to $Z_b$ and $\\eta_b\\;\\rho$.",
        "positive": "Bosonic color-flavor transformation for the special unitary group: We extend Zirnbauer's color-flavor transformation in the bosonic sector to\nthe color group SU(N_c). Because the flavor group U(N_b, N_b) is non-compact,\nthe algebraic method by which the original color-flavor transformation was\nderived leads to a useful result only for 2N_b \\le N_c. Using the character\nexpansion method, we obtain a different form of the transformation in the\nextended range N_b \\le N_c. This result can also be used for the color group\nU(N_c). The integrals to which the transformation can be applied are of\nrelevance for the recently proposed boson-induced lattice gauge theory."
    },
    {
        "anchor": "Density of observables from local derivatives: We derive a formula to calculate the local change to the log of any density\nof states for smooth real observables. Using this in Monte-Carlo simulations,\nwe are able to calculate the expectation value of the observable with a\nprecision often better than standard sampling. The method can be applied to\npreviously generated configurations, as long as the analysis uses the same\naction used to generate the configurations. We show that for observables such\nas Wilson line correlators, errors are reduced by up to 4 times.",
        "positive": "Scattering amplitude from Bethe-Salpeter wave function inside the\n  interaction range: We propose a method to calculate scattering amplitudes using the\nBethe-Salpeter wave function inside the interaction range on the lattice. For\nan exploratory study of this method, we evaluate a scattering length of $I=2$\nS-wave two pions by the use of the on-shell scattering amplitude. Our result is\nconfirmed to be consistent with the value obtained from the conventional finite\nvolume method. The half-off-shell scattering amplitude is also evaluated."
    },
    {
        "anchor": "Hagedorn spectrum and thermodynamics of SU(2) and SU(3) Yang-Mills\n  theories: We present a high-precision lattice calculation of the equation of state in\nthe confining phase of SU(2) Yang-Mills theory. We show that the results are\ndescribed very well by a gas of massive, non-interacting glueballs, provided\none assumes an exponentially growing Hagedorn spectrum. The latter can be\nderived within an effective bosonic closed-string model, leading to a\nparameter-free theoretical prediction, which is in perfect agreement with our\nlattice results. Furthermore, when applied to SU(3) Yang-Mills theory, this\neffective model accurately describes the lattice results reported by Bors\\'anyi\net al. in JHEP 07 (2012) 056.",
        "positive": "Solution of symmetry equation and hierarchy of self dual Yang-Mills\n  systems: The solution of symmetry equation of Yang-Mills self dual system is found in\nexplicit form of its raising Hamiltonian operator. Thus explicit form of\nequations of self dual Yang Mills hierarchy is constructed."
    },
    {
        "anchor": "Charm sea effects on charmonium decay constants and heavy meson masses: We estimate the effects on the decay constants of charmonium and on heavy\nmeson masses due to the charm quark in the sea. Our goal is to understand\nwhether for these quantities $N_f=2+1$ lattice QCD simulations provide results\nthat can be compared with experiments or whether $N_f=2+1+1$ QCD including the\ncharm quark in the sea needs to be simulated. We consider two theories, $N_f=0$\nQCD and QCD with $N_f=2$ charm quarks in the sea. The charm sea effects (due to\ntwo charm quarks) are estimated comparing the results obtained in these two\ntheories, after matching them and taking the continuum limit. The absence of\nlight quarks allows us to simulate the $N_f=2$ theory at lattice spacings down\nto $0.023$ fm that are crucial for reliable continuum extrapolations. We find\nthat sea charm quark effects are below $1\\%$ for the decay constants of\ncharmonium. Our results show that decoupling of charm works well up to energies\nof about $500$ MeV. We also compute the derivatives of the decay constants and\nmeson masses with respect to the charm mass. For these quantities we again do\nnot see a significant dynamical charm quark effect, albeit with a lower\nprecision. For mesons made of a charm quark and a heavy antiquark, whose mass\nis twice that of the charm quark, sea effects are only about $0.1\\%$ in the\nratio of vector to pseudoscalar masses.",
        "positive": "Constructing a composite Higgs model with built-in large separation of\n  scales: Experimentally the existence of a light 125 GeV Higgs boson is well\nestablished but so far no other heavier resonances have been observed. Viable\nmodels to describe the Higgs boson as composite particle require hence to\nexhibit a large separation of scales. This occurs naturally in systems located\nnear a conformal fixed point irrespective whether the system lies outside or\ninside the conformal window. We demonstrate the latter case by investigating a\nmass-split model with four light and six heavy flavors. By construction\nmass-split models exhibit a large separation of scales and feature in addition\na highly constrained hadron spectrum. We present results based on the low-lying\nconnected meson spectrum. Although the light sector is chirally broken, we show\nthat it exhibits hyperscaling which is typical for conformal systems."
    },
    {
        "anchor": "Undesirable effects of covariance matrix techniques for error analysis: Regression with $\\chi^2$ constructed from the covariance matrix should not be\nused for some combinations of covariance matrices and fitting functions. Using\nthe technique for unsuitable combinations can amplify systematic errors. This\namplification is uncontrolled, and can produce arbitrarily inaccurate results\nthat might not be ruled out by a $\\chi^2$ test. In addition, this technique can\ngive incorrect (artificially small) errors for fit parameters. I give a test\nfor this instability and a more robust (but computationally more intensive)\nmethod for fitting correlated data.",
        "positive": "Computing the nucleon charge and axial radii directly at $Q^2=0$ in\n  lattice QCD: We describe a procedure for extracting momentum derivatives of nucleon matrix\nelements on the lattice directly at $Q^2=0$. This is based on the Rome method\nfor computing momentum derivatives of quark propagators. We apply this\nprocedure to extract the nucleon isovector magnetic moment and charge radius as\nwell as the isovector induced pseudoscalar form factor at $Q^2=0$ and the axial\nradius. For comparison, we also determine these quantities with the traditional\napproach of computing the corresponding form factors, i.e. $G^v_E(Q^2)$ and\n$G_M^v(Q^2)$ for the case of the vector current and $G_P^v(Q^2)$ and\n$G_A^v(Q^2)$ for the axial current, at multiple $Q^2$ values followed by\n$z$-expansion fits. We perform our calculations at the physical pion mass using\na 2HEX-smeared Wilson-clover action. To control the effects of excited-state\ncontamination, the calculations were done at three source-sink separations and\nthe summation method was used. The derivative method produces results\nconsistent with those from the traditional approach but with larger statistical\nuncertainties especially for the isovector charge and axial radii."
    },
    {
        "anchor": "Colour Fields of the Static Pentaquark System Computed in SU(3) Lattice\n  QCD: We compute the colour fields of SU(3) lattice QCD created by static\npentaquark systems, in a $24^3\\times 48$ lattice at $\\beta=6.2$ corresponding\nto a lattice spacing $a=0.07261(85)$ fm. We find that the pentaquark colour\nfields are well described by a multi-Y-type shaped flux tube. The flux tube\njunction points are compatible with Fermat-Steiner points minimizing the total\nflux tube length. We also compare the pentaquark flux tube profile with\ndiquark-diantiquark central flux tube profile in the tetraquark and the\nquark-antiquark fundamental flux tube profile in the meson, and they match,\nthus showing that the pentaquark flux tubes are composed of fundamental flux\ntubes.",
        "positive": "Quantum State Preparation for the Schwinger Model: It is not possible, using standard lattice techniques in Euclidean space, to\ncalculate the complete fermionic spectrum of a quantum field theory. Algorithms\nrunning on quantum computers have the potential to access the theory with\nreal-time evolution, enabling a direct computation. As a testing ground we\nconsider the 1 + 1-dimensional Schwinger model with the presence of a {\\theta}\nterm using a staggered fermions discretization. We study the convergence\nproperties of two different algorithms - adiabatic evolution and the Quantum\nApproximate Optimization Algorithm - with an emphasis on their cost in terms of\nCNOT gates. This is crucial to understand the feasibility of these algorithms,\nbecause calculations on near-term quantum devices depend on their rapid\nconvergence. We also propose a blocked algorithm that has the first indications\nof a better scaling behavior with the dimensionality of the problem."
    },
    {
        "anchor": "The origin of space-time as seen from matrix model simulations: The AdS/CFT correspondence, or more generally the gauge/gravity duality, is a\nremarkable conjecture obtained from superstring theory with various D-brane\nbackgrounds. According to this conjecture, a higher-dimensional curved\nspace-time emerges from supersymmetric gauge theory in lower-dimensional flat\nspace-time. In the first part of this article, we review Monte Carlo studies of\nU(N) supersymmetric gauge theories, which confirmed the gauge/gravity duality\nfor various observables. In particular, Monte Carlo results for thermodynamic\nquantities enable us to understand the microscopic origin of the black hole\nentropy associated with the dual geometry. We also discuss results for Wilson\nloops and correlation functions, which agree nicely with the predictions from\nthe gravity side. In the second part, we review recent developments in a\nnonperturbative formulation of superstring theory, which may be regarded as a\ncounterpart of the lattice gauge theory in QCD. In particular, we discuss Monte\nCarlo results for the Lorentzian matrix model, which suggest that\n(3+1)-dimensional expanding universe emerges dynamically from type IIB\nsuperstring theory in (9+1) dimensions if one treats the theory\nnonperturbatively.",
        "positive": "Higher-Twist Contribution to Pion Structure Function: 4-Fermi Operators: We present quenched lattice QCD results for the contribution of higher-twist\noperators to the lowest non-trivial moment of the pion structure function. To\nbe specific, we consider the combination $F_2^{\\pi^+} + F_2^{\\pi^-} - 2\nF_2^{\\pi^0}$ which has $I = 2$ and receives contributions from 4-Fermi\noperators only. We introduce the basis of lattice operators. The\nrenormalization of the operators is done perturbatively in the $\\bar{\\rm{MS}}$\nscheme using the 't Hooft-Veltman prescription for $\\gamma_5$, taking\nparticular care of mixing effects. The contribution is found to be of\n$O(f_\\pi^2/Q^2)$, relative to the leading contribution to the moment of\n$F_2^{\\pi^+}$."
    },
    {
        "anchor": "Nuclear Lattice Simulations with EFT: This proceedings article is a summary of results from work done in\ncollaboration with Bugra Borasoy and Thomas Schaefer. We study nuclear and\nneutron matter by combining chiral effective field theory with non-perturbative\nlattice methods. We present results for hot neutron matter at temperatures 20\nto 40 MeV and densities below twice nuclear matter density.",
        "positive": "$B$-meson semileptonic decays from highly improved staggered quarks: We present an update for results on $B$-meson semileptonic decays using the\nhighly improved staggered quark (HISQ) action for both valence and 2+1+1 sea\nquarks. The use of the highly improved action, combined with the MILC\ncollaboration's gauge ensembles with lattice spacings down to $\\sim$0.03 fm,\nallows the $b$ quark to be treated with the same discretization as the lighter\nquarks. The talk will focus on updated results for $B_{(s)} \\to D_{(s)}$,\n$B_{(s)} \\to K$ scalar and vector form factors."
    },
    {
        "anchor": "Semi-leptonic decays of heavy mesons and the Isgur-Wise function in\n  quenched lattice QCD: The form factors for the semi-leptonic B->D and B->D* decays are evaluated in\nquenched lattice QCD at two different values of the coupling, beta=6.0 and 6.2.\nThe action and the operators are fully O(a) non-perturbatively improved. The\nslope of the Isgur-Wise function is evaluated, and found to be\nrho^2=0.83^{+15+24}_{-11-1} (quoted errors are statistical and systematic\nrespectively). Ratios of form factors are evaluated and compared to\nexperimental determinations.",
        "positive": "The gradient flow in a twisted box: We study the perturbative behavior of the gradient flow in a twisted box. We\napply this information to define a running coupling using the energy density of\nthe flow field. We study the step-scaling function and the size of cutoff\neffects in SU(2) pure gauge theory. We conclude that the twisted gradient flow\nrunning coupling scheme is a valid strategy for step-scaling purposes due to\nthe relatively mild cutoff effects and high precision."
    },
    {
        "anchor": "Supersymmetric Yang-Mills theory: a step towards the continuum: The spectrum of supersymmetric Yang-Mills theory presented so far shows an\nunexpected gap between the bosonic and fermionic masses. This finding was in\ncontradiction with the basic requirements of supersymmetry. In this work we\nwill present new results indicating that the mass gap is reduced at a smaller\nlattice spacing. Hence lattice artifacts are the most likely explanation for\nit. These new results have been obtained at a larger beta value and on a larger\nlattice.",
        "positive": "Wilson, fixed point and Neuberger's lattice Dirac operator for the\n  Schwinger model: We perform a comparison between different lattice regularizations of the\nDirac operator for massless fermions in the framework of the single and two\nflavor Schwinger model. We consider a) the Wilson-Dirac operator at the\ncritical value of the hopping parameter; b) Neuberger's overlap operator; c)\nthe fixed point operator. We test chiral properties of the spectrum, dispersion\nrelations and rotational invariance of the mesonic bound state propagators."
    },
    {
        "anchor": "Four-loop logarithms in 3d gauge + Higgs theory: We discuss the logarithmic contributions to the vacuum energy density of the\nthree-dimensional SU(3) + adjoint Higgs theory in its symmetric phase, and\nrelate them to numerical Monte Carlo simulations. We also comment on the\nimplications of these results for perturbative and non-perturbative\ndeterminations of the pressure of finite-temperature QCD.",
        "positive": "Connected and disconnected contributions to nucleon axial form factors\n  using $N_f=2$ twisted mass fermions at the physical point: We present results on the isovector and isoscalar nucleon axial form factors\nincluding disconnected contributions,using an ensemble of $N_f =2$ twisted mass\nclover- improved Wilson fermions simulated with approximately the physical\nvalue of the pion mass. The light disconnected quark loops are computed using\nexact deflation, while the strange and the charm quark loops are evaluated\nusing the truncated solver method. Techniques such as the summation and the\ntwo-state fits have been employed to access ground-state dominance."
    },
    {
        "anchor": "Massive Fermions in Lattice Gauge Theory: This paper presents a formulation of lattice fermions applicable to all quark\nmasses, large and small. We incorporate interactions from previous\nlight-fermion and heavy-fermion methods, and thus ensure a smooth connection to\nthese limiting cases. The couplings in improved actions are evaluated for\narbitrary fermion mass~$m_q$, without expansions around small- or large-mass\nlimits. We treat both the action and external currents. By interpreting\non-shell improvement criteria through the lattice theory's Hamiltonian, one\nfinds that cutoff artifacts factorize into the form\n$b_n(m_qa)[\\vek{p}a]^{s_n}$, where $\\vek{p}$ is a momentum characteristic of\nthe system under study, $s_n$ is related to the dimension of the $n$th\ninteraction, and $b_n(m_qa)$ is a bounded function, numerically\nalways~$\\order(1)$ or less. In heavy-quark systems $\\vek{p}$ is typically\nrather smaller than the fermion mass~$m_q$. Therefore, artifacts of order\n$(m_qa)^s$ do not arise, even when $m_qa\\gsim1$. An important by-product of our\nanalysis is an interpretation of the Wilson and Sheikholeslami-Wohlert actions\napplied to nonrelativistic fermions.",
        "positive": "The charm-quark contribution to light-by-light scattering in the muon\n  $(g-2)$ from lattice QCD: We compute the hadronic light-by-light scattering contribution to the muon\n$g-2$ from the charm quark using lattice QCD. The calculation is performed on\nensembles generated with dynamical $(u,d,s)$ quarks at the SU(3)$_{\\rm f}$\nsymmetric point with degenerate pion and kaon masses of around 415 MeV. It\nincludes the connected charm contribution, as well as the leading disconnected\nWick contraction, involving the correlation between a charm and a light-quark\nloop. Cutoff effects turn out to be sizeable, which leads us to use\nlighter-than-physical charm masses, to employ a broad range of lattice spacings\nreaching down to 0.039 fm and to perform a combined charm-mass and continuum\nextrapolation. We use the $\\eta_c$ meson to define the physical charm-mass\npoint and obtain a final value of $a_\\mu^{\\rm HLbL,c} = (2.8\\pm 0.5) \\times\n10^{-11}$, whose uncertainty is dominated by the systematics of the\nextrapolation. Our result is consistent with the estimate based on a simple\ncharm-quark loop, whilst being free of any perturbative scheme dependence on\nthe charm mass. The mixed charm-light disconnected contraction contributes a\nsmall negative amount to the final value."
    },
    {
        "anchor": "Tensor lattice field theory with applications to the renormalization\n  group and quantum computing: We discuss the successes and limitations of statistical sampling for a\nsequence of models studied in the context of lattice QCD and emphasize the need\nfor new methods to deal with finite-density and real-time evolution. We show\nthat these lattice models can be reformulated using tensorial methods where the\nfield integrations in the path-integral formalism are replaced by discrete\nsums. These formulations involve various types of duality and provide exact\ncoarse-graining formulas which can be combined with truncations to obtain\npractical implementations of the Wilson renormalization group program. Tensor\nreformulations are naturally discrete and provide manageable transfer matrices.\nCombining truncations with the time continuum limit, we derive Hamiltonians\nsuitable to perform quantum simulation experiments, for instance using cold\natoms, or to be programmed on existing quantum computers. We review recent\nprogress concerning the tensor field theory treatment of non-compact scalar\nmodels, supersymmetric models, economical four-dimensional algorithms,\nnoise-robust enforcement of Gauss's law, symmetry preserving truncations and\ntopological considerations. We discuss connections with other tensor network\napproaches.",
        "positive": "Precision for B-meson matrix elements: We demonstrate how HQET and the Step Scaling Method for B-physics, pioneered\nby the Tor Vergata group, can be combined to reach a further improved\nprecision. The observables considered are the mass of the b-quark and the\nB_s-meson decay constant. The demonstration is carried out in quenched lattice\nQCD. We start from a small volume, where one can use a standard O(a)-improved\nrelativistic action for the b-quark, and compute two step scaling functions\nwhich relate the observables to the large volume ones. In all steps we\nextrapolate to the continuum limit, separately in HQET and in QCD for masses\nbelow m_b. The physical point m_b is then reached by an interpolation of the\ncontinuum results in 1/m. The essential, expected and verified, feature is that\nthe step scaling fuctions have a weak mass-dependence resulting in an easy\ninterpolation to the physical point. With r_0=0.5fm and the experimental B_s\nand K masses as input, we find F_Bs=191(6)MeV and the renormalization group\ninvariant mass M_b=6.88(10)GeV, translating into m_b(m_b)=4.42(6)GeV in the\nMSbar scheme. This approach seems very promising for full QCD."
    },
    {
        "anchor": "Some universal features of the effective string picture of pure gauge\n  theories: The effective string describing the large distance behaviour of the quark\nsources of gauge field theories in the confining phase in D=3 or D=4 space-time\ndimensions can be formulated, in the infrared limit, as a suitable 2D conformal\nfield theory on surfaces with quark loops as boundaries. Recent results on\nself-avoiding random surfaces allow to fix almost uniquely such a conformal\ntheory. As a consequence, some universal relationships among the string tension\n, the thickness of the colour flux tube, the deconfinement temperature and a\nlower bound of the glueball mass spectrum are found. The general agreement with\nthe data extracted from recent lattice simulations with different gauge groups\nis rather impressive.(Talk held by F.Gliozzi at Lattice'92 , Amsterdam)",
        "positive": "Random Matrices and the Convergence of Partition Function Zeros in\n  Finite Density QCD: We apply the Glasgow method for lattice QCD at finite chemical potential to a\nschematic random matrix model (RMM). In this method the zeros of the partition\nfunction are obtained by averaging the coefficients of its expansion in powers\nof the chemical potential. In this paper we investigate the phase structure by\nmeans of Glasgow averaging and demonstrate that the method converges to the\ncorrect analytically known result. We conclude that the statistics needed for\ncomplete convergence grows exponentially with the size of the system, in our\ncase, the dimension of the Dirac matrix. The use of an unquenched ensemble at\n$\\mu=0$ does not give an improvement over a quenched ensemble.\n  We elucidate the phenomenon of a faster convergence of certain zeros of the\npartition function. The imprecision affecting the coefficients of the\npolynomial in the chemical potential can be interpeted as the appearance of a\nspurious phase. This phase dominates in the regions where the exact partition\nfunction is exponentially small, introducing additional phase boundaries, and\nhiding part of the true ones. The zeros along the surviving parts of the true\nboundaries remain unaffected."
    },
    {
        "anchor": "Semi-Analytical Solution of the $\u03c6^4$ Theory on an $F_4$ Lattice: Investigating the cutoff dependence of the Higgs mass triviality bound, the\n$\\phi^4$ theory is formulated on an $F_4$ lattice which preserves Lorentz\ninvariance to a higher degree than the commonly used hypercubic lattice. I\nsolve this model non-perturbatively by evaluating the high temperature\nexpansion through 13th order following the approach of L\\\"uscher and Weisz. The\nresults are continued across the transition line into the broken phase by\nintegrating the perturbative RG equations. In the broken phase, the\nrenormalized coupling never exceeds 2/3 of the tree level unitarity bound when\n$\\Lambda/m_R \\geq 2$. The results confirm recent Monte Carlo data and I obtain\nas an upper bound for the Higgs mass $m_R/f_\\pi \\leq 2.46 \\pm 0.02_{\\rm HTE}\n\\pm 0.08_{\\rm PT}$ at $\\Lambda/m_R=2$.",
        "positive": "Reply to Comment on ``Asymptotic Scaling in the Two-Dimensional O(3)\n  sigma-Model at Correlation Length 10^5\": We reply to criticism by Patrascioiu and Seiler [hep-lat/9502019] of our\nresults [Phys. Rev. Lett. 75, 1891 (1995), hep-lat/9411009] on asymptotic\nscaling in the two-dimensional $O(3)$ $\\sigma$-model, which were based on a\nfinite-size-scaling extrapolation method."
    },
    {
        "anchor": "Spin Correlations and Velocity-Scaling in NRQCD Matrix Elements: We compute spin-dependent matrix elements for decays of S-wave quarkonia in\nlattice NRQCD. They appear to be in approximate agreement with the\nvelocity-scaling rules of NRQCD.",
        "positive": "Benchmarking and tuning the MILC code on clusters and supercomputers: Recently, we have benchmarked and tuned the MILC code on a number of\narchitectures including Intel Itanium and Pentium IV (PIV), dual-CPU Athlon,\nand the latest Compaq Alpha nodes. Results will be presented for many of these,\nand we shall discuss some simple code changes that can result in a very\ndramatic speedup of the KS conjugate gradient on processors with more advanced\nmemory systems such as PIV, IBM SP and Alpha."
    },
    {
        "anchor": "Lattice Results for Heavy Light Matrix Elements: Lattice results for heavy light matrix elements are reviewed and some of\ntheir implications are very briefly discussed. Despite the fact that in most\ncases the lattice results for weak matrix elements at the moment have only a\nmodest accuracy of about 20--30\\% they already have important phenomenological\nrepercussions; e.g.\\ for $V_{td}/V_{ts}$, $x_s/x_d$ and $B\\to K^\\ast\\gamma$.\nPresented at the XXVII International Conference on High Energy Physics,\nGlasgow, July 1994.",
        "positive": "Abelian gauge fields coupled to simplicial quantum gravity: We study the coupling of Abelian gauge theories to four-dimensional\nsimplicial quantum gravity. The gauge fields live on dual links. This is the\ncorrect formulation if we want to compare the effect of gauge fields on\ngeometry with similar effects studied so far for scalar fields. It shows that\ngauge fields couple equally weakly to geometry as scalar fields, and it offers\nan understanding of the relation between measure factors and Abelian gauge\nfields observed so-far."
    },
    {
        "anchor": "Relevant energy scale of color confinement from lattice QCD: We propose a new lattice framework to extract the relevant gluonic energy\nscale of QCD phenomena which is based on a \"cut\" on link variables in momentum\nspace. This framework is expected to be broadly applicable to all lattice QCD\ncalculations. Using this framework, we quantitatively determine the relevant\nenergy scale of color confinement, through the analyses of the quark-antiquark\npotential and meson masses. The relevant energy scale of color confinement is\nfound to be below 1.5 GeV in the Landau gauge. In fact, the string tension is\nalmost unchanged even after cutting off the high-momentum gluon component above\n1.5 GeV. When the relevant low-energy region is cut, the quark-antiquark\npotential is approximately reduced to a Coulomb-like potential, and each meson\nbecomes a quasi-free quark pair. As an analytical model calculation, we also\ninvestigate the dependence of the Richardson potential on the cut, and find the\nconsistent behavior with the lattice result.",
        "positive": "Nonassociative Algebras and Nonperturbative Field Theory for\n  Hierarchical Models: Hierarchical renormalization group (RG) transformations are related to\nnonassociative algebras. These algebras serve as a new basic tool for a\nrigorous treatment of global RG flows and the search of nontrivial infrared\nfixed points. Convergent expansion methods are presented and analyzed in terms\nof algebra norms. It is shown that the infrared fixed points are solutions of a\nquadratic equation with an infinite number of unknowns. A continuous manifold\nof two dimensional periodic nontrivial fixed points is presented in terms of\ntheta functions. Local Borel summability of the $\\epsilon$- expansion for\nn-well fixed points is proved by algebraic methods."
    },
    {
        "anchor": "Meson spectrum in SU(N) gauge theories with quarks in higher\n  representations: A check of Casimir scaling hypothesis: Gauge theories with gauge group $SU(N)$ and quarks belonging to arbitrary\nrepresentations of $SU(N)$ form a rich landscape of QCD-like theories, whose\nstudy can shed new light on the properties of confinement. Four cases are\nparticularly worth of interest: quarks in the fundamental representation,\nquarks in the 2-indice (anti)symmetric representation and quarks in the adjoint\nrepresentation. The last three corresponding QCD-like theories are equivalent\nat large-$N$ for bosonic observables: It is the orientifold equivalence. The\nbehavior of the lightest vector meson mass versus $N$ has been studied in\nquenched lattice QCD in the chiral limit in these theories. We show that the\nobserved behaviors are compatible with a string tension proportional to the\nquadratic Casimir of $SU(N)$ in the quark color representation, $\\textit{i.e.}$\nwith the Casimir scaling hypothesis. The large-$N$ limit of some excited meson\nmasses computed in quenched lattice QCD with quarks in the fundamental\nrepresentation is also shown to be compatible with QCD string's well-known\nsignature: Regge trajectories.",
        "positive": "The chirally improved quark propagator and restoration of chiral\n  symmetry: The chirally improved (CI) quark propagator in Landau gauge is calculated in\ntwo flavor lattice Quantum Chromodynamics. Its wave-function renormalization\nfunction $Z(p^2)$ and mass function $M(p^2)$ are studied. To minimize lattice\nartifacts, tree-level improvement of the propagator and tree-level correction\nof the lattice dressing functions is applied. Subsequently the CI quark\npropagator under Dirac operator low-mode removal is investigated. The\ndynamically generated mass in the infrared domain of the mass function is found\nto dissolve continuously as a function of the reduction level and strong\nsuppression of $Z(p^2)$ for small momenta is observed."
    },
    {
        "anchor": "Listening to Noise: We show how sign problems in simulations of many-body systems can manifest\nthemselves in the form of heavy-tailed correlator distributions, similar to\nwhat is seen in electron propagation through disordered media. We propose an\nalternative statistical approach for extracting ground state energies in such\nsystems, illustrating the method with a toy model and with lattice data for\nunitary fermions and for baryons in QCD.",
        "positive": "How Do Fermions Behave on a Random Lattice?: Comparing random lattice, naive and Wilson fermions in two dimensional\nabelian background gauge field, we show that the doublers suppressed in the\nfree field case are revived for random lattices in the continuum limit unless\ngauge interactions are implemented in a non--invariant way."
    },
    {
        "anchor": "Lattice QCD: Flavor Physics and Spectroscopy: We review highlights of recent results on the hadron spectrum and flavor\nphysics from lattice QCD. We also discuss recent rapid progress on the muon\nanomalous magnetic moment.",
        "positive": "SU(N) Gauge Theories with C-Periodic Boundary Conditions: II. Small\n  Volume Dynamics: The dynamics of SU(N) gauge theories, especially for N=3, in a small\nC-periodic box are investigated. We identify the fields that mimimize the\nenergy---the torons---and determine which of these ``classical'' vacua are\nstable quantum mechanically. The stable torons break cubic symmetry, which has\ninteresting consequences on the spectrum. At any of the stable torons there are\nalso quartic modes. Since all C-periodic boundary conditions are\ngauge-equivalent, we choose a convenient version, for which the quartic modes\nare constant modes, and compute the effective Hamiltonian to one loop in\nperturbation theory."
    },
    {
        "anchor": "Free energies of static three quark systems: We study the behaviour of free energies of baryonic systems composed of three\nheavy quarks on the lattice in SU(3) pure gauge theory at finite temperature.\nFor all temperatures above $T_c$ we find that the connected part of the singlet\n(decuplet) free energy of the three quark system is given by the sum of the\nconnected parts of the free energies of $qq$-triplets (-sextets). Using\nrenormalized free energies we can compare free energies in different colour\nchannels as well as those of $qq$- and $qqq$-systems on an unique energy scale.",
        "positive": "Baryonic Screening Masses in High Temperature QCD: We compute the screening masses of fields with nucleon quantum numbers for a\nwide range of temperatures between $T \\sim 1$ GeV and $T\\sim 160$ GeV. The\ncomputation has been performed by means of Monte Carlo simulations of lattice\nQCD with $N_f=3$ flavors of $O(a)$-improved Wilson fermions: we exploit a novel\nstrategy which has recently allowed to determine for the first time non-singlet\nmesonic screening masses up to extremely high temperatures. The baryonic\nscreening masses are measured with a few per-mille precision in the continuum\nlimit, and percent deviations from the free theory result $3\\pi T$ are clearly\nvisible even at the highest temperatures. The observed degeneracy of the\npositive and negative parity state's screening mass, expected from Ward\nidentities associated to non-singlet axial transformations, provides further\nevidence for the restoration of chiral symmetry in the high temperature regime\nof QCD."
    },
    {
        "anchor": "The 3-loop Beta Function of QCD: Using the background field technique, we calculate the 3-loop beta function\nof lattice $SU(N)$ gauge theories. In the pure gluonic case, we present our\nresults, comparing to those recently obtained by Luescher and Weisz. We also\nprovide a progress report in the case of QCD with Wilson fermions.",
        "positive": "Lattice Study on quantum-mechanical dynamics of two-color QCD with six\n  light flavors: We investigate the chiral properties of SU(2) gauge theory with six flavors,\ni.e. six light Dirac fermions in the fundamental representations by lattice\nsimulation, and point out that the spontaneous breakdown of chiral symmetry\ndoes not occur in this system. The quark mass dependence of the mesonic\nspectrum provides an evidence for such a possibility. The decay constant tends\nto be increased by the finite size effect, which is opposite to the behavior\npredicted by chiral perturbation theory and indicates that the long distance\ndynamics in the six-flavor theory could be different from the theory with\nchiral symmetry breaking. The subtracted chiral condensate, whose utility is\ndemonstrated by the simulation of two-flavor theory, is shown to vanish in the\nchiral limit within the precision of available data."
    },
    {
        "anchor": "Relationship between the Euclidean and Lorentzian versions of the type\n  IIB matrix model: The type IIB matrix model was proposed as a non-perturbative formulation of\nsuperstring theory in 1996. We simulate a model that describes the late time\nbehavior of the IIB matrix model by applying the complex Langevin method to\novercome the sign problem. We clarify the relationship between the Euclidean\nand the Lorentzian versions of the type IIB matrix model in a recently\ndiscovered phase. By introducing a constraint, we obtain a model where the\nspacetime metric is Euclidean at early times, whereas it {\\it dynamically}\nbecomes Lorentzian at late times.",
        "positive": "Perturbative study of renormalization and mixing for asymmetric\n  staple-shaped Wilson-line operators on the lattice: We present one-loop perturbative results of the renormalization functions for\na complete set of nonlocal quark bilinear operators containing an asymmetric\nstaple-shaped Wilson line, using a family of improved lattice actions. This\nstudy is relevant for the nonperturbative investigations regarding the\nrenormalization of the unpolarized, helicity and transversity\ntransverse-momentum dependent parton distribution functions (TMDPDFs) in\nlattice QCD. We employ a number of different versions of\nregularization-independent (RI$'$) renormalization prescriptions which address\nthe power and logarithmic divergences of such nonlocal operators, the\npinch-pole singularities at infinite Wilson-line lengths, as well as the mixing\namong operators of different Dirac structures, as dictated by discrete\nsymmetries. All cancelations of divergences and admixtures are confirmed by our\nresults at one-loop level. We compare all the different prescriptions and we\nprovide the conversion matrices at one-loop order which relate the matrix\nelements of the staple operators in RI$'$ to the reference scheme\n$\\overline{\\rm MS}$."
    },
    {
        "anchor": "Density of states techniques for lattice field theories using the\n  functional fit approach (FFA): We discuss a variant of density of states (DoS) techniques for lattice field\ntheories, the so-called \"functional fit approach\" (FFA). The DoS FFA is based\non a density of states rho(x) which is parameterized on small intervals of the\nargument x of rho(x). On these intervals restricted Monte Carlo simulations\nwith an additional Boltzmann factor exp(lambda x) allow to determine rho(x)\nvery precisely by obtaining its parameters from fitting the Monte Carlo data to\na known function of lambda. We describe the method in detail and show its\napplicability in four different systems, three of which have a complex action\nproblem: The SU(3) spin model with a chemical potential, U(1) lattice gauge\ntheory, the Z(3) spin model with chemical potential, and 2-dimensional U(1)\nlattice gauge theory with a topological term. In all cases we compare to\nreference calculations, which partly were done in a dual formulation where the\ncomplex action problem is absent. In all four cases we find a very encouraging\nperformance of the DoS FFA.",
        "positive": "Charmonium-like states from scattering on the lattice: Three charmonium-like states were studied using lattice QCD. The candidate\nfor X(3872) was found slightly below DD* threshold in the channel with\nJ^PC=1^++ and I=0, where cc as well as DD* and $J/\\psi \\omega$ interpolating\noperators were used. A charmonium-like channel with J^PC=1^+- and I=1 was also\nstudied, as the recently discovered Z_c^+(3900) might reside there. Here\n$J/\\psi \\pi$ and DD* scattering states were found, but no candidate for the\nZ_c^+(3900). We present also preliminary results for the J^PC=0^++ charmonium\nchannel, where cc, DD and $J/\\psi \\omega$ interpolating operators were used. A\ncandidate for a resonance, chi_c0^', that couples to DD in J^PC=0^++ was found."
    },
    {
        "anchor": "Numerical study of the scaling properties of SU(2) lattice gauge theory\n  in Palumbo non-compact regularization: In the framework of a non-compact lattice regularization of nonabelian gauge\ntheories we look, in the SU(2) case, for the scaling window through the\nanalysis of the ratio of two masses of hadronic states. In the two-dimensional\nparameter space of the theory we find the region where the ratio is constant,\nand equal to the one in the Wilson regularization. In the scaling region we\ncalculate the lattice spacing, finding it at least 20% larger than in the\nWilson case; therefore the simulated physical volume is larger.",
        "positive": "Nucleon isovector tensor charge from lattice QCD with physical light\n  quarks: We present preliminary results for the axial, scalar and tensor charges of\nthe nucleon measured in 2+1 flavor QCD with the physical light quarks\n($m_\\pi=135$ MeV). Our simulations are carried out with gauge configurations\ngenerated by the PACS Collaboration with the stout-smeared $O(a)$ improved\nWilson fermions and Iwasaki gauge action at a single lattice spacing of $0.085\\\n(\\mathrm{fm})$. There are two lattice ensembles of the PACS gauge\nconfigurations, which have physical lattice sizes over $(10\\ \\mathrm{fm})^4$\nand $(5\\ \\mathrm{fm})^4$, respectively. We compute the nucleon three-point\ncorrelation functions in the axial, scalar, and tensor channels. For the\nrenormalization, we use the Rome-Southampton method as the intermediate scheme\nin order to evaluate the renormalization constants for the scalar and tensor\ncurrents in fully nonperturbative manner. We then evaluate the renormalized\nvalues of the scalar and tensor charges ($g_S$ and $g_T$) in the $\\overline{\\rm\nMS}$ scheme at the renormalization scale of 2 GeV with a help of the continuum\nperturbation theory for the matching between two schemes. We compare our\npreliminary results of $g_S$ and $g_T$ with those of other collaboration\nresults."
    },
    {
        "anchor": "Gluon propagators in maximal abelian gauge of SU(2) lattice gauge theory: We study propagators of diagonal and off-diagonal gluons in the momentum\nspace in maximal abelian gauge of SU(2) lattice gauge theory. Remaining U(1)\ndegrees of freedom are fixed using Landau gauge. We find substantial difference\nbetween the propagator of the diagonal and the off-diagonal gluon in the\ninfrared region. The propagator of the off-diagonal gluon is suppressed in\ncomparison with that of the diagonal gluon at small momenta. In the ultraviolet\nregion both propagators behave as in nonabelian Landau gauge.",
        "positive": "Electric and magnetic Landau-gauge gluon propagators in\n  finite-temperature SU(2) gauge theory: We perform lattice simulations in pure-SU(2) Yang-Mills theory to investigate\nhow the infrared behavior of electric and magnetic gluon propagators in Landau\ngauge is affected by temperature. We consider the largest lattices to date, in\nan attempt to keep systematic errors under control. Electric and magnetic\nscreening masses are calculated through an Ansatz from the zero-temperature\ncase, based on complex-conjugate poles for the momentum-space propagators. As\nrecently reported in [1], we find good fits to the proposed form at all\ntemperatures considered, with different ratios of real to imaginary part of the\npole masses for the longitudinal (electric) and transverse (magnetic)\npropagators. The behavior of the magnetic propagator D_T(p) is in agreement\nwith the dimensional-reduction picture, showing infrared suppression (with a\nturnover in momentum) and violation of spectral positivity at all nonzero\ntemperatures considered. The longitudinal propagator D_L(p) appears to reach a\nplateau at small momenta and is subject to severe finite-Nt effects around the\ncritical temperature Tc. As a consequence, only lattices with temporal extent\nNt > 8 seem to be free from systematic errors. After these errors are removed,\nthe infrared-plateau value is considerably reduced around the transition and\nthe sharp peak observed previously for this quantity at Tc is no longer\npresent. The resulting infrared behavior for D_L(p) at Tc is essentially the\nsame as for 0.5Tc . An investigation of the temperature range between 0.5Tc and\nTc reveals that a less pronounced (finite) peak may occur at smaller\ntemperatures, e.g. T ~ 0.9Tc."
    },
    {
        "anchor": "The Phase Diagram of Fluid Random Surfaces with Extrinsic Curvature: We present the results of a large-scale simulation of a Dynamically\nTriangulated Random Surface with extrinsic curvature embedded in\nthree-dimensional flat space. We measure a variety of local observables and use\na finite size scaling analysis to characterize as much as possible the regime\nof crossover from crumpled to smooth surfaces.",
        "positive": "Global obstructions to gauge-invariance in chiral gauge theory on the\n  lattice: It is shown that certain global obstructions to gauge-invariance in chiral\ngauge theory, described in the continuum by Alvarez-Gaume and Ginsparg, are\nexactly reproduced on the lattice in the Overlap formulation at small non-zero\nlattice spacing (i.e. close to the classical continuum limit). As a\nconsequence, the continuum anomaly cancellation condition $d_R^{abc}=0$ is seen\nto be a necessary (although not necessarily sufficient) condition for anomaly\ncancellation on the lattice in the Overlap formulation."
    },
    {
        "anchor": "Green's Functions and Topological Configurations: There are, among others, currently two important views on the\nnon-perturbative structure of Yang-Mills theory. One is through topological\nconfigurations and one is through Green's functions, in particular their\n(asymptotic) infrared behavior. Based on both views, various scenarios for\nconfinement, chiral symmetry breaking and other non-perturbative effects have\nbeen developed. However, if both views are correct then they can only be\ndifferent aspects of the same underlying physics, and it must be possible to\nrelate them.\n  After discussing the current status of the understanding of this connection,\nsmeared and cooled configurations in lattice gauge theory are used to determine\nthe properties of Green's functions in the low-momentum regime. It is found\nthat the qualitative properties are essentially unchanged compared to results\non unsmeared configurations. This is also the case when the configurations are\nsmeared sufficiently strongly to reach the almost (anti-)self-dual domain.",
        "positive": "Isolating the Roper Resonance in Lattice QCD: We present results for the first positive parity excited state of the\nnucleon, namely, the Roper resonance ($N^{{{1/2}}^{+}}$=1440 MeV) from a\nvariational analysis technique. The analysis is performed for pion masses as\nlow as 224 MeV in quenched QCD with the FLIC fermion action. A wide variety of\nsmeared-smeared correlation functions are used to construct correlation\nmatrices. This is done in order to find a suitable basis of operators for the\nvariational analysis such that eigenstates of the QCD Hamiltonian may be\nisolated. A lower lying Roper state is observed that approaches the physical\nRoper state.\n  To the best of our knowledge, the first time this state has been identified\nat light quark masses using a variational approach."
    },
    {
        "anchor": "Parton distributions from lattice QCD: We extract the x dependence of the nonsinglet u-d distribution function in\nthe nucleon from the lowest few moments calculated on the lattice, using an\nextrapolation formula which ensures the correct behavior in the chiral and\nheavy quark limits. We discuss the implications for the quark mass dependence\nof meson masses lying on the J(PC)=1(--) Regge trajectory.",
        "positive": "Translating topological benefits in very cold lattice simulations: Master-field simulations offer an approach to lattice QCD in which\ncalculations are performed on a small number of large-volume gauge-field\nconfigurations. The latter is advantageous for simulations in which the global\ntopological charge is frozen due to a very fine lattice spacing, as the effect\nof this on observables is suppressed by the spacetime volume. Here we make use\nof the recently developed Stabilised Wilson Fermions to investigate a variation\nof this approach in which only the temporal direction ($T$) is taken larger\nthan in traditional calculations. As compared to a hyper-cubic lattice\ngeometry, this has the advantage that finite-$L$ effects can be useful, e.g.\nfor multi-hadron observables, while compared to open boundary conditions,\ntime-translation invariance is not lost.\n  In this proof-of-concept contribution, we study the idea of using very cold\n(i.e. long-$T$) lattices to topologically \"defrost\" observables at fine lattice\nspacing. We identify the scalar-scalar meson two-point correlation function as\na useful probe and present first results from $N_f=3$ ensembles with time\nextents up to $T=2304$ and a lattice spacing of $a=0.055\\,\\rm{fm}$."
    },
    {
        "anchor": "Thermal phase structure of dimensionally reduced super-Yang--Mills: We present our current results from ongoing lattice investigations of the\nBerenstein--Maldacena--Nastase deformation of maximally supersymmetric\nYang--Mills quantum mechanics. We focus on the thermal phase structure of this\ntheory, which depends on both the temperature $T$ and the deformation parameter\n$\\mu$, through the dimensionless ratios $T / \\mu$ and $g = \\lambda / \\mu^3$\nwith $\\lambda$ the 't Hooft coupling. We determine the critical $T / \\mu$ of\nthe confinement transition for couplings $g$ that span three orders of\nmagnitude, to connect weak-coupling perturbative calculations and large-$N$\ndual supergravity predictions in the strong-coupling limit. Analyzing multiple\nlattice sizes up to $N_{\\tau} = 24$ and numbers of colors up to $N = 16$ allows\ninitial checks of the large-$N$ continuum limit.",
        "positive": "Phase structure and real-time dynamics of the massive Thirring model in\n  1+1 dimensions using the tensor-network method: We present concluding results from our study for zero-temperature phase\nstructure of the massive Thirring model in 1+1 dimensions with staggered\nregularisation. Employing the method of matrix product states, several\nquantities, including two types of correlators, are investigated, leading to\nnumerical evidence of a Berezinskii-Kosterlitz-Thouless phase transition.\nExploratory results for real-time dynamics pertaining to this transition,\nobtained using the approaches of variational uniform matrix product state and\ntime-dependent variational principle, are also discussed."
    },
    {
        "anchor": "Investigating the Sharpe-Singleton scenario on the lattice by direct\n  eigenvalue computation: We investigate the phase structure of lattice QCD with dynamical Wilson\nfermions. Wilson chiral perturbation theory predicts that the Aoki phase and\nthe Sharpe-Singleton scenario manifest themselves in very distinct behavior of\nthe Wilson Dirac eigenvalue spectrum. To test this prediction we perform a\ndirect calculation of the eigenvalues of the non-Hermitian Wilson Dirac\noperator in dynamical lattice simulations. Moreover, we demonstrate an\nunexpected quark mass dependence on the shape of the eigenvalue distribution in\nthe positive quark mass side.",
        "positive": "Spectroscopy of Charmed and Bottom Hadrons using Lattice QCD: We present preliminary results on the light, charmed and bottom baryon\nspectra using overlap valence quarks on the background of 2+1+1 flavours HISQ\ngauge configurations of the MILC collaboration. These calculations are\nperformed on three different gauge ensembles at three lattice spacings (a ~\n0.12 fm, 0.09 fm and 0.06 fm) and for physical strange, charm and bottom quark\nmasses. The SU(2) heavy baryon chiral perturbation theory is used to\nextrapolate baryon masses to the physical pion mass and the continuum limit\nextrapolations are also performed. Our results are consistent with the well\nmeasured charmed baryons. We predict the masses of many other states which are\nyet to be discovered."
    },
    {
        "anchor": "Renormalisation of the scalar energy-momentum tensor with the Wilson\n  flow: The non-perturbative computation of the energy-momentum tensor can be used to\nstudy the scaling behaviour of strongly coupled quantum field theories. The\nWilson flow is an essential tool to find a meaningful formulation of the\nenergy-momentum tensor on the lattice. We extend recent studies of the\nrenormalisation of the energy-momentum tensor in four-dimensional gauge theory\nto the case of a three-dimensional scalar theory to investigate its intrinsic\nstructure and numerical feasibility on a more basic level. In this paper, we\ndiscuss translation Ward identities, introduce the Wilson flow for scalar\ntheory, and present our results for the renormalisation constants of the scalar\nenergy-momentum tensor.",
        "positive": "Polyakov loop correlators and cyclic Wilson loop from lattice QCD: We discuss color screening in 2+1 flavor QCD in terms of free energies of a\nstatic quark-antiquark pair. Thermal modifications of long distance\ncorrelations in quark-antiquark systems are studied in terms of static meson\ncorrelators. We calculate the Polyakov loop correlator, the color-singlet\nWilson line correlator in Coulomb gauge and the cyclic Wilson loop on lattices\nusing the HISQ/Tree action and almost physical quark mases with $N_\\tau= 4, 6,\n8, 10, 12$. We present results in the continuum limit for temperatures up to $T\n\\lesssim 650$ MeV and discuss the linear divergence of the cyclic Wilson loop."
    },
    {
        "anchor": "4D $\\mathcal{N}=1$ SYM supercurrent on the lattice in terms of the\n  gradient flow: The gradient flow[1-5] gives rise to a versatile method to construct\nrenormalized composite operators in a regularization-independent manner. By\nadopting this method, the authors of~Refs.[6-9] obtained the expression of\nNoether currents on the lattice in the cases where the associated symmetries\nare broken by lattice regularization. We apply the same method to the Noether\ncurrent associated with supersymmetry, i.e., the supercurrent. We consider the\n4D $\\mathcal{N}=1$ super Yang--Mills theory and calculate the renormalized\nsupercurrent in the one-loop level in the Wess--Zumino gauge. We then\nre-express this supercurrent in terms of the flowed gauge and flowed gaugino\nfields[10].",
        "positive": "Taste non-Goldstone pion decay constants in staggered chiral\n  perturbation theory: We calculate the next-to-leading order axial current decay constants of taste\nnon-Goldstone pions and kaons in staggered chiral perturbation theory. This is\nan extension of the taste Goldstone decay constants calculation to that of the\nnon-Goldstone tastes. We present results for the partially quenched case in the\nSU(3) and SU(2) staggered chiral perturbation theories and discuss the\ndifference between the taste Goldstone and non-Goldstone cases."
    },
    {
        "anchor": "Confinement: $G_2$ group case: The gauge group being centreless, $G_2$ gauge theory is a good laboratory for\nstudying the role of the centre of the group for colour confinement in\nYang-Mills gauge theories. In this paper, we investigate $G_2$ pure gauge\ntheory at finite temperature on the lattice. By studying the finite size\nscaling of the plaquette, the Polyakov loop and their susceptibilities, we show\nthat a deconfinement phase transition takes place. The analysis of the\npseudocritical exponents give strong evidence of the deconfinement transition\nbeing first order. Implications of our findings for scenarios of colour\nconfinement are discussed.",
        "positive": "Geometrical Volume Effects in the Computation of the Slope of the\n  Isgur-Wise Function: We use a method recently suggested for evaluating the slope of the Isgur-Wise\nfunction, at the zero-recoil point, on the lattice. The computations are\nperformed in the quenched approximation to lattice QCD, on a $24^3 \\times 48$\nlattice at $\\beta=6.2$, using an $O(a)$-improved action for the fermions. We\nhave found unexpectedly large finite-volume effects in such a calculation.\nThese volume corrections turned out to be purely geometrical and independent of\nthe dynamics of the system. After the study of these effects on a smaller\nvolume and for different quark masses, we give approximate expressions that\naccount for them. Using these approximations we find $\\xi^\\prime(1)=-1.7 \\pm\n0.2$ and $\\xi^\\prime(1)=-1.4 +0.2-0.1$ for the slope of the Isgur-Wise\nfunction, for two mesons composed of a heavy quark slightly heavier and\nlighter, respectively, than the charm quark, and in both cases, a light\nantiquark whose mass is about that of the strange quark."
    },
    {
        "anchor": "Three-particle quantization condition: an update: We give an update on our derivation of a quantization condition relating the\nfinite-volume spectrum of three particles in a cubic box to infinite-volume\nscattering quantities. We have discovered and fixed technical problems in the\nderivation sketched in the proceedings of last year's lattice conference\n[arXiv:1311.4848], and have presented a detailed description of the corrected\nderivation in Ref. [arXiv:1408.5933]. Here we give an overview of the problems\nand their solutions, and describe open questions.",
        "positive": "Flavour blindness and patterns of flavour symmetry breaking in lattice\n  simulations of up, down and strange quarks: QCD lattice simulations with 2+1 flavours (when two quark flavours are mass\ndegenerate) typically start at rather large up-down and strange quark masses\nand extrapolate first the strange quark mass and then the up-down quark mass to\nits respective physical value. Here we discuss an alternative method of tuning\nthe quark masses, in which the singlet quark mass is kept fixed. Using group\ntheory the possible quark mass polynomials for a Taylor expansion about the\nflavour symmetric line are found, first for the general 1+1+1 flavour case and\nthen for the 2+1 flavour case. This ensures that the kaon always has mass less\nthan the physical kaon mass. This method of tuning quark masses then enables\nhighly constrained polynomial fits to be used in the extrapolation of hadron\nmasses to their physical values. Numerical results for the 2+1 flavour case\nconfirm the usefulness of this expansion and an extrapolation to the physical\npion mass gives hadron mass values to within a few percent of their\nexperimental values. Singlet quantities remain constant which allows the\nlattice spacing to be determined from hadron masses (without necessarily being\nat the physical point). Furthermore an extension of this programme to include\npartially quenched results is given."
    },
    {
        "anchor": "Electromagnetic Form Factors of Nucleon Excitations in Lattice QCD: Variational analysis techniques in lattice QCD are powerful tools that give\naccess to the full spectrum of QCD. At zero momentum, these techniques are well\nestablished and can cleanly isolate energy eigenstates of either positive or\nnegative parity. In order to compute the form factors of a single energy\neigenstate, we must perform a variational analysis at non-zero momentum. When\nwe do this with baryons, we run into issues with parity mixing in the Dirac\nspinors, as boosted baryons are not eigenstates of parity. Due to this parity\nmixing, care must be taken to ensure that the projected correlation functions\nprovided by the variational analysis correspond to the same states at zero\nmomentum. This can be achieved through the parity-expanded variational analysis\n(PEVA) technique, a novel method developed at the University of Adelaide for\nensuring the successful and consistent isolation of boosted baryons. Utilising\nthis technique, we are able to compute the form factors of baryon excitations\nwithout contamination from other states. We present world-first calculations of\nexcited state nucleon form factors using this new technique.",
        "positive": "Pathologies of Quenched Lattice QCD at non--zero Density and its\n  Effective Potential: We simulate lattice QCD at non--zero baryon density and zero temperature in\nthe quenched approximation, both in the scaling region and in the infinite\ncoupling limit. We investigate the nature of the forbidden region -- the range\nof chemical potential where the simulations grow prohibitively expensive, and\nthe results, when available, are puzzling if not unphysical. At weak coupling\nwe have explored the sensitivity of these pathologies to the lattice size, and\nfound that using a large lattice ($64 \\times 16^3$) does not remove them. The\neffective potential sheds considerable light on the problems in the\nsimulations, and gives a clear interpretation of the forbidden region. The\nstrong coupling simulations were particularly illuminating on this point."
    },
    {
        "anchor": "k-String tensions and their large-N dependence: We consider whether the 1/N corrections to k-string tensions must begin at\norder 1/N^2, as in the Sine Law, or whether odd powers of 1/N, as in Casimir\nScaling, are also acceptable. The issue is important because different models\nof confinement differ in their predictions for the representation-dependence of\nk-string tensions, and corrections involving odd powers of 1/N would seem to be\nruled out by the large-N expansion. We show, however, that k-string tensions\nmay, in fact, have leading 1/N corrections, and consistency with the large-N\nexpansion, in the open string sector, is achieved by an exact pairwise\ncancellation among terms involving odd powers of 1/N in particular combinations\nof Wilson loops. It is shown how these cancellations come about in a concrete\nexample, namely, strong coupling lattice gauge theory with the heat-kernel\naction, in which k-string tensions follow the Casimir scaling rule.",
        "positive": "B-parameters of the complete set of matrix elements of (Delta B = 2)\n  operators from the lattice: We compute on the lattice the ``bag'' parameters of the five (Delta B = 2)\noperators of the supersymmetric basis, by combining their values determined in\nfull QCD and in the static limit of HQET. The extrapolation of the QCD results\nfrom the accessible heavy-light meson masses to the B-meson mass is constrained\nby the static result. The matching of the corresponding results in HQET and in\nQCD is for the first time made at NLO accuracy in the MSbar(NDR)\nrenormalization scheme. All results are obtained in the quenched approximation."
    },
    {
        "anchor": "Study of two color QCD on large lattices: We study two colors lattice QCD (QC$_2$D) with two flavors of staggered\nfermions on $40^4$ and $32^4$ lattices with lattice spacing $a =0.048$~fm in\nthe wide range of the quark chemical potential $\\mu_q$. Our focus is on the\nconfinement-deconfinement transition in this theory. Thus we compute the string\ntension from the Wilson loops and the static quark free energy from the\nPolyakov loops. We find that the deconfinement transition found earlier in the\nrange $\\mu_q \\approx 800 - 1000$ MeV is shifted to higher values. This shift is\nattributed to decreasing of the lattice spacing used in our simulations in\ncomparison with the earlier study.",
        "positive": "Matrix model correlation functions and lattice data for the QCD Dirac\n  operator with chemical potential: We apply a complex chiral random matrix model as an effective model to QCD\nwith a small chemical potential at zero temperature. In our model the\ncorrelation functions of complex eigenvalues can be determined analytically in\ntwo different limits, at weak and strong non-Hermiticity. We compare them to\nthe distribution of the smallest Dirac operator eigenvalues from quenched QCD\nlattice data for small values of the chemical potential, appropriately rescaled\nwith the volume. This confirms the existence of two different scaling regimes\nfrom lattice data."
    },
    {
        "anchor": "Modelling the Quark Determinant in Full QCD Simulations: The computational requirements and dynamics of Monte Carlo simulations of\nunquenched QCD incorporating the infrared quark eigenmodes (up to $\\approx\n\\Lambda_{QCD}$) exactly and UV modes via a loop representation are discussed.\nThe accuracy of such a loop representation is studied for a variety of lattice\nvolumes and quark masses. The method has been successfully applied for lattices\nup to 10$^3$x20 at $a \\simeq$0.17F with improved (clover) action, and allows\nsimulations at or near kappa critical.",
        "positive": "Renormalization of the Lattice HQET Isgur-Wise Function: We compute the perturbative renormalization factors required to match to the\ncontinuum Isgur-Wise function, calculated using lattice Heavy Quark Effective\nTheory. The velocity, mass, wavefunction and current renormalizations are\ncalculated for both the forward difference and backward difference actions for\na variety of velocities. Subtleties are clarified regarding tadpole\nimprovement, regulating divergences, and variations of techniques used in these\nrenormalizations."
    },
    {
        "anchor": "Digital quantum simulation and Pseudoquantum Simulation of\n  $\\mathbb{Z}_2$ Gauge Higgs Model: We present a quantum algorithm for digital quantum simulation of the\n$\\mathbb{Z}_2$ gauge-Higgs model on a $3\\times 3$ lattice, which is based on\nTrotter decomposition, the quantum adiabatic algorithm and its circuit\nrealization. Then we perform a classical demonstration, dubbed a pseudoquantum\nsimulation, on a GPU simulator. We obtain useful results on this model, which\nsuggest the topological properties of the deconfined phase and help to clarify\nthe phase diagram. It is suggested that the tricitical point, where the\nsecond-order critical lines of deconfinement-confinement transition and of\ndeconfinement-Higgs transition meet, seems to be on the the first-order\ncritical line of confinement-Higgs transition, at a point other than the end of\nthis critical line.",
        "positive": "Digitizing lattice gauge theories in the magnetic basis: reducing the\n  breaking of the fundamental commutation relations: We present a digitization scheme for the lattice $\\mathrm{SU}(2)$ gauge\ntheory Hamiltonian in the $\\mathit{magnetic}$ $\\mathit{basis}$, where the gauge\nlinks are unitary and diagonal. The digitization is obtained from a particular\npartitioning of the $\\mathrm{SU}(2)$ group manifold, with the canonical momenta\nconstructed by an approximation of the Lie derivatives on this partitioning.\nThis construction, analogous to a discrete Fourier transform, preserves the\nspectrum of the kinetic part of the Hamiltonian and the canonical commutation\nrelations exactly on a subspace of the truncated Hilbert space, while the\nresidual subspace can be projected above the cutoff of the theory."
    },
    {
        "anchor": "QCD phase diagram with isospin chemical potential: In this contribution we investigate the phase diagram of QCD in the presence\nof an isospin chemical potential. To alleviate the infrared problems of the\ntheory associated with pion condensation, we introduce the pionic source as an\ninfrared regulator. We discuss various methods to extrapolate the results to\nvanishing pionic source, including a novel method based on the singular value\nspectrum of the massive Dirac operator, a leading-order reweighting and a\nspline Monte-Carlo fit. Our main results concern the phase transition boundary\nbetween the normal and the pion condensation phases and the\nchiral/deconfinement transition temperature as a function of the chemical\npotential. In addition, we perform a quantitative comparison between our direct\nresults and a Taylor-expansion obtained at zero chemical potential to assess\nthe applicability range of the latter.",
        "positive": "Meson masses in electromagnetic fields with Wilson fermions: We determine the light meson spectrum in QCD in the presence of background\nmagnetic fields using quenched Wilson fermions. Our continuum extrapolated\nresults indicate a monotonous reduction of the connected neutral pion mass as\nthe magnetic field grows. The vector meson mass is found to remain nonzero, a\nfinding relevant for the conjectured $\\rho$-meson condensation at strong\nmagnetic fields. The continuum extrapolation was facilitated by adding a novel\nmagnetic field-dependent improvement term to the additive quark mass\nrenormalization. Without this term, sizable lattice artifacts that would\ndeceptively indicate an unphysical rise of the connected neutral pion mass for\nstrong magnetic fields are present. We also investigate the impact of these\nlattice artifacts on further observables like magnetic polarizabilities and\ndiscuss the magnetic field-induced mixing between $\\rho$-mesons and pions. We\nalso derive Ward-Takashi identities for QCD+QED both in the continuum\nformulation and for (order $a$-improved) Wilson fermions."
    },
    {
        "anchor": "Local coherence and deflation of the low quark modes in lattice QCD: The spontaneous breaking of chiral symmetry in QCD is known to be linked to a\nnon-zero density of eigenvalues of the massless Dirac operator near the origin.\nNumerical studies of two-flavour QCD now suggest that the low quark modes are\nlocally coherent to a certain extent. As a consequence, the modes can be\nsimultaneously deflated, using local projectors, with a total computational\neffort proportional to the lattice volume (rather than its square). Deflation\nhas potentially many uses in lattice QCD. The technique is here worked out for\nthe case of quark propagator calculations, where large speed-up factors and a\nflat scaling behaviour with respect to the quark mass are achieved.",
        "positive": "Strange quark content of the nucleon: We discuss the calculation of disconnected diagrams needed for determining\nthe strange quark content of the nucleon on the lattice. We present results for\nthe strange scalar form factor and the related parameter f_Ts, which enters\ninto the cross-section for the scattering of dark matter off nuclei in\nsupersymmetric extensions of the standard model. In addition, we present\nresults for the strange contribution to the nucleon's axial and electromagnetic\nform factors. The calculations were performed with two dynamical flavors of\nWilson fermions on a 24^3 x 64 anisotropic lattice with a_s = 3a_t = 0.11 fm\nand M_pi ~ 400 MeV."
    },
    {
        "anchor": "QCD thermodynamics with continuum extrapolated Wilson fermions II: We continue our investigation of 2+1 flavor QCD thermodynamics using\ndynamical Wilson fermions in the fixed scale approach. Two additional pion\nmasses, approximately 440 MeV and 285 MeV, are added to our previous work at\n545 MeV. The simulations were performed at 3 or 4 lattice spacings at each pion\nmass. The renormalized chiral condensate, strange quark number susceptibility\nand Polyakov loop is obtained as a function of the temperature and we observe a\ndecrease in the light chiral pseudo-critical temperature as the pion mass is\nlowered while the pseudo-critical temperature associated with the strange quark\nnumber susceptibility or the Polyakov loop is only mildly sensitive to the pion\nmass. These findings are in agreement with previous continuum results obtained\nin the staggered formulation.",
        "positive": "Quark mass anomalous dimension and $\u039b_{\\overline{\\textrm{MS}}}$\n  from the twisted mass Dirac operator spectrum: We investigate whether it is possible to extract the quark mass anomalous\ndimension and its scale dependence from the spectrum of the twisted mass Dirac\noperator in Lattice QCD. The answer to this question appears to be positive,\nprovided that one goes to large enough eigenvalues, sufficiently above the\nnon-perturbative regime. The obtained results are compared to continuum\nperturbation theory. By analyzing possible sources of systematic effects, we\nfind the domain of applicability of the approach, extending from an energy\nscale of around 1.5 to 4 GeV. The lower limit is dictated by physics\n(non-perturbative effects at low energies), while the upper bound is set by the\nultraviolet cut-off of present-day lattice simulations. The information about\nthe scale dependence of the anomalous dimension allows also to extract the\nvalue of the $\\Lambda_{\\overline{\\textrm{MS}}}$-parameter of 2-flavour QCD,\nyielding the value $303(13)(25)$ MeV, where the first error is statistical and\nthe second one systematic. We use gauge field configuration ensembles generated\nby the European Twisted Mass Collaboration (ETMC) with 2 flavours of dynamical\ntwisted mass quarks, at 4 lattice spacings in the range between around 0.04 and\n0.08 fm."
    },
    {
        "anchor": "Electromagnetic Self-Duality in a Lattice Model: We formulate a Euclidean lattice theory of interacting elementary spin-half\nelectric and magnetic charges, which we refer to as electrons and magnetic\nmonopoles respectively. The model uses the polymer representation of the\nfermion determinant, and exhibits a self-dual symmetry provided electric charge\n$e$ and magnetic charge $g$ obey the minimal Dirac quantisation condition\n$eg=2\\pi$. In a hopping parameter expansion at lowest order, we show that\nvirtual electron and monopole loops contribute radiative corrections of\nopposite sign to the photon propagator. We argue that in the limit $e\\to0$,\nfermion mass $\\mu\\to0$, the model describes QED together with strongly\ninteracting monopoles whose chiral symmetry is spontaneously broken. Prospects\nfor the existence of an interacting continuum limit at the self-dual point\n$e=g$ are discussed.",
        "positive": "Topics in Lattice QCD and Effective Field Theory: Effective field theories provide a formalism for categorizing low-energy\neffects of a high-energy fundamental theory in terms of the low-energy degrees\nof freedom. This process has been well established in mapping the fundamental\ntheory of QCD in terms of the hadronic degrees of freedom, which allows for\nquantitative connections and predictions between hardronic observables. A more\ndirect approach to performing the non-perturbative QCD calculations is through\nlattice QCD. These computationally intensive calculations approximate continuum\nphysics with a discretized lattice to extract hadronic phenomena from first\nprinciples. However, as in any approximation, there are multiple systematic\nerrors between lattice QCD calculation and actual hardronic phenomena. To\naccount for these systematic effects in terms of hadronic interactions,\neffective field theory proves to be useful. However, the fundamental theory of\ninterest here is lattice QCD, as opposed to the usual continuum QCD. In this\nwork, the basics of this process are outlined, and multiple original\ncalculations are presented: effective field theory for anisotropic lattices,\nI=2 $\\pi\\pi$ scattering for isotropic, anisotropic, and twisted mass lattices.\nAdditionally, a usage of effective field theories and the employment of an\nisospin chemical potential on the lattice is proposed to extract several\ncomputationally difficult scattering parameters. Lastly, recently proposed\nlocal, chiral lattice actions are analyzed in the framework of effective field\ntheory, which illuminates various challenges in simulating such actions."
    },
    {
        "anchor": "Status of the Finite Temperature Electroweak Phase Transition on the\n  Lattice: I review the status of non-perturbative investigations of the finite\ntemperature electroweak phase transition by means of lattice simulations.",
        "positive": "The bulk transition of QCD with twelve flavors and the role of\n  improvement: We study the SU(3) gauge theory with Nf=12 flavors in the fundamental\nrepresentation by use of lattice simulations with staggered fermions. With a\nnon-improved action we observe a chiral zero-temperature (bulk) transition\nseparating a region at weak coupling, where chiral symmetry is realized, from a\nregion at strong coupling where chiral symmetry is broken. With improved\nactions, a more complicated pattern emerges, and in particular two first order\ntransitions in the chiral limit appear. We observe that at sufficiently strong\ncoupling the next-to-nearest neighbor terms of the improved lattice action are\nno longer irrelevant and can indeed modify the pattern observed without\nimprovement. Baryon number conservation can be realized in an unusual way,\nallowing for an otherwise prohibited oscillating term in the pseudoscalar\nchannel. We discuss the phenomenon by means of explicit examples borrowed from\nstatistical mechanics. Finally, these observations can also be useful when\nsimulating other strongly coupled systems on the lattice, such as graphene."
    },
    {
        "anchor": "Thermodynamical quantities of lattice full QCD from an efficient method: I extend to QCD an efficient method for lattice gauge theory with dynamical\nfermions. Once the eigenvalues of the Dirac operator and the density of states\nof pure gluonic configurations at a set of plaquette energies (proportional to\nthe gauge action) are computed, thermodynamical quantities deriving from the\npartition function can be obtained for arbitrary flavor number, quark masses\nand wide range of coupling constants, without additional computational cost.\nResults for the chiral condensate and gauge action are presented on the $10^4$\nlattice at flavor number $N_f=0$, 1, 2, 3, 4 and many quark masses and coupling\nconstants. New results in the chiral limit for the gauge action and its\ncorrelation with the chiral condensate, which are useful for analyzing the QCD\nchiral phase structure, are also provided.",
        "positive": "Implementation of Symanzik's Improvement Program for Simulations of\n  Dynamical Wilson Fermions in Lattice QCD: We discuss the implementation of a Sheikholeslami-Wohlert term for\nsimulations of lattice QCD with dynamical Wilson fermions as required by\nSymanzik's improvement program. We show that for the Hybrid Monte Carlo or\nKramers equation algorithm standard even-odd preconditioning can be maintained.\nWe design tests of the implementation using analytically and numerically\ncomputed cumulant expansions. We find that, for situations where the average\nnumber of Conjugate Gradient iterations exceeds 200, the overhead is only about\n20%."
    },
    {
        "anchor": "Multi-point Pad\u00e8 for the study of phase transitions: from the Ising\n  model to lattice QCD: The Bielefeld Parma collaboration has recently put forward a method to\ninvestigate the QCD phase diagram based on the computation of Taylor series\ncoefficients at both zero and imaginary values of the baryonic chemical\npotential. The method is based on the computation of multi-point Pad\\`e\napproximants. We review the methodological aspects of the computation and, in\norder to gain confidence in the approach, we report on the application of the\nmethod to the two-dimensional Ising model (probably the most popular arena for\ntesting tools in the study of phase transitions). Besides showing the\neffectiveness of the multi-point Pad\\`e approach, we discuss what these results\ncan suggest in view of further progress in the study of the QCD phase diagram.\nWe finally report on very preliminary results in which we look for Pad\\`e\napproximants at different temperatures and fixed values of the (imaginary)\nbaryonic chemical potential.",
        "positive": "pMR: A high-performance communication library: On many parallel machines, the time LQCD applications spent in communication\nis a significant contribution to the total wall-clock time, especially in the\nstrong-scaling limit. We present a novel high-performance communication library\nthat can be used as a de facto drop-in replacement for MPI in existing\nsoftware. Its lightweight nature that avoids some of the unnecessary overhead\nintroduced by MPI allows us to improve the communication performance of\napplications without any algorithmic or complicated implementation changes. As\na first real-world benchmark, we make use of the pMR library in the coarse-grid\nsolve of the Regensburg implementation of the DD-$\\alpha$AMG algorithm. On\nrealistic lattices, we see an improvement of a factor 2x in pure communication\ntime and total execution time savings of up to 20%."
    },
    {
        "anchor": "Wilson loops in very high order lattice perturbation theory: We calculate Wilson loops of various sizes up to loop order $n=20$ for\nlattice sizes of $L^4 (L=4, 6, 8, 12)$ using the technique of Numerical\nStochastic Perturbation Theory in quenched QCD. This allows to investigate the\nbehaviour of the perturbative series at high orders. We discuss three models to\nestimate the perturbative series: a renormalon inspired fit, a heuristic fit\nbased on an assumed power-law singularity and boosted perturbation theory. We\nhave found differences in the behavior of the perturbative series for smaller\nand larger Wilson loops at moderate $n$. A factorial growth of the coefficients\ncould not be confirmed up to $n=20$. From Monte Carlo measured plaquette data\nand our perturbative result we estimate a value of the gluon condensate\n$<\\frac{\\alpha}{\\pi}GG>$.",
        "positive": "QCD strings ending on domain walls --- a complete wetting phenomenon in\n  SUSY QCD: In the context of M-theory, Witten has argued that an intriguing phenomenon\noccurs, namely that QCD strings can end on domain walls. We present a simpler\nexplanation of this effect using effective field theory to describe the\nbehavior of the Polyakov loop and the gluino condensate in N = 1 supersymmetric\nQCD. We describe how domain walls separating distinct confined phases appear in\nthis effective theory and how these interfaces are completely wet by a film of\ndeconfined phase at the high-temperature phase transition. This gives the\nPolyakov loop a non-zero expectation value on the domain wall. Consequently, a\nstatic test quark which is close to the interface has a finite free energy and\nthe string emanating from it can end on the wall."
    },
    {
        "anchor": "Spin 3/2 Penta-quarks in anisotropic lattice QCD: A high-precision mass measurement for the pentaquark (5Q) Theta^+ in\nJ^P=3/2^{\\pm} channel is performed in anisotropic quenched lattice QCD using a\nlarge number of gauge configurations as N_{conf}=1000. We employ the standard\nWilson gauge action at beta=5.75 and the O(a) improved Wilson (clover) quark\naction with kappa=0.1210(0.0010)0.1240 on a 12^3 \\times 96 lattice with the\nrenormalized anisotropy as a_s/a_t = 4. The Rarita-Schwinger formalism is\nadopted for the interpolating fields. Several types of the interpolating fields\nwith isospin I=0 are examined such as (a) the NK^*-type, (b) the\n(color-)twisted NK^*-type, (c) a diquark-type. The chiral extrapolation leads\nto only massive states, i.e., m_{5Q} \\simeq 2.1-2.2 GeV in J^P=3/2^- channel,\nand m_{5Q} = 2.4-2.6 GeV in J^P=3/2^+ channel. The analysis with the hybrid\nboundary condition(HBC) is performed to investigate whether these states are\ncompact 5Q resonances or not. No low-lying compact 5Q resonance states are\nfound below 2.1GeV.",
        "positive": "Taylor expansions and Pad\u00e9 approximants for cumulants of conserved\n  charge fluctuations at non-vanishing chemical potentials: Using high statistics datasets generated in (2+1)-flavor QCD calculations at\nfinite temperature we present results for low order cumulants of net\nbaryon-number fluctuations at non-zero values of the baryon chemical potential.\nWe calculate Taylor expansions for the pressure (zeroth order cumulant), net\nbaryon-number density (first order cumulant) and the variance of the\ndistribution on net-baryon number fluctuations (second order cumulant). We\nobtain series expansions from an eighth order expansion of the pressure and\ncompare these to diagonal Pad\\'e approximants. This allows us to estimate the\nrange of values for the baryon chemical potential in which these expansions are\nreliable. We find $\\mu_B/T\\le 2.5$, $2.0$ and $1.5$ for the zeroth, first and\nsecond order cumulants, respectively. We furthermore, construct estimators for\nthe radius of convergence of the Taylor series of the pressure. In the vicinity\nof the pseudo-critical temperature, $T_{pc}\\simeq 156.5$ MeV, we find $\\mu_B/T\n\\gtrsim\\ 2.9$ at vanishing strangeness chemical potential and somewhat larger\nvalues for strangeness neutral matter. These estimates are temperature\ndependent and range from $\\mu_B/T \\gtrsim\\ 2.2$ at $T=135$ MeV to $\\mu_B/T\\\n\\gtrsim\\ 3.2$ at $T=165$ MeV. The estimated radius of convergences is the same\nfor any higher order cumulant."
    },
    {
        "anchor": "Selected inversion as key to a stable Langevin evolution across the QCD\n  phase boundary: We present new results of full QCD at nonzero chemical potential. In PRD 92,\n094516 (2015) the complex Langevin method was shown to break down when the\ninverse coupling decreases and enters the transition region from the deconfined\nto the confined phase. We found that the stochastic technique used to estimate\nthe drift term can be very unstable for indefinite matrices. This may be\navoided by using the full inverse of the Dirac operator, which is, however, too\ncostly for four-dimensional lattices. The major breakthrough in this work was\nachieved by realizing that the inverse elements necessary for the drift term\ncan be computed efficiently using the selected inversion technique provided by\nthe parallel sparse direct solver package PARDISO. In our new study we show\nthat no breakdown of the complex Langevin method is encountered and that\nsimulations can be performed across the phase boundary.",
        "positive": "Alternative Numerical Techniques: Two new approaches to numerical QFT are presented."
    },
    {
        "anchor": "Fractal Dimension of Gauge-fixing Defects: The fractal dimension $D_f$ of sites resisting Landau or maximal Abelian(MA)\ngauge fixing in lattice $SU(3)$ gluodynamics is defined and computed. In Landau\ngauge such sites clump into $D_f\\sim 1$ clusters in the confining phase. In the\nfinite temperature phase their dimensionality drops to $D_f < 1$, that is,\nclustering seems to dissipate. In contrast, MA gauge resistant sites fail to\nexhibit a notable tendency to cluster at any temperature.",
        "positive": "Crossing the Gribov horizon: an unconventional study of geometric\n  properties of gauge-configuration space in Landau gauge: We prove a lower bound for the smallest nonzero eigenvalue of the\nLandau-gauge Faddeev-Popov matrix in Yang-Mills theories. The bound is written\nin terms of the smallest nonzero momentum on the lattice and of a parameter\ncharacterizing the geometry of the first Gribov region. This allows a simple\nand intuitive description of the infinite-volume limit in the ghost sector. In\nparticular, we show how nonperturbative effects may be quantified by the rate\nat which typical thermalized and gauge-fixed configurations approach the Gribov\nhorizon. Our analytic results are verified numerically in the SU(2) case\nthrough an informal, free and easy, approach. This analysis provides the first\nconcrete explanation of why the so-called scaling solution of the\nDyson-Schwinger equations is not observed in lattice studies."
    },
    {
        "anchor": "Energy shift of the three-particle system in a finite volume: Using the three-particle quantization condition recently obtained in the\nparticle-dimer framework, the finite-volume energy shift of the two lowest\nthree-particle scattering states is derived up to and including order $L^{-6}$.\nFurthermore, assuming that a stable dimer exists in the infinite volume, the\nshift for the lowest particle-dimer scattering state is obtained up to and\nincluding order $L^{-3}$. The result for the lowest three-particle state agrees\nwith the results from the literature, and the result for the lowest\nparticle-dimer state reproduces the one obtained by using the Luescher\nequation.",
        "positive": "Propagators in Coulomb gauge from SU(2) lattice gauge theory: A thorough study of 4-dimensional SU(2) Yang-Mills theory in Coulomb gauge is\nperformed using large scale lattice simulations. The (equal-time) transverse\ngluon propagator, the ghost form factor d(p) and the Coulomb potential V_{coul}\n(p) ~ d^2(p) f(p)/p^2 are calculated. For large momenta p, the gluon propagator\ndecreases like 1/p^{1+\\eta} with \\eta =0.5(1). At low momentum, the propagator\nis weakly momentum dependent. The small momentum behavior of the Coulomb\npotential is consistent with linear confinement. We find that the inequality\n\\sigma_{coul} \\ge \\sigma comes close to be saturated. Finally, we provide\nevidence that the ghost form factor d(p) and f(p) acquire IR singularities,\ni.e., d(p) \\propto 1/\\sqrt{p} and f(p) \\propto 1/p, respectively. It turns out\nthat the combination g_0^2 d_0(p) of the bare gauge coupling g_0 and the bare\nghost form factor d_0(p) is finite and therefore renormalization group\ninvariant."
    },
    {
        "anchor": "Inverse Symmetry Breaking on the lattice: an accurate MC study: We present here a new MC study of ISB at finite temperature in a $Z_2\\times\nZ_2$ $\\lambda\\phi^4$ model in four dimensions. The results of our simulations,\neven if not conclusive, are favourable to ISB. Detection of the effect required\nmeasuring some critical couplings with six-digits precision, a level of\naccuracy that could be achieved only by a careful use of FSS techniques. The\ngap equations for the Debye masses, resulting from the resummation of the ring\ndiagrams, seem to provide a qualitatively correct description of the data,\nwhile the simple one-loop formulae appear to be inadequate.",
        "positive": "Lattice Gauge Theory and (Quasi)-Conformal Technicolor: QCD with 2 flavours of massless colour-sextet quarks is studied as a theory\nwhich might exhibit a range of scales over which the running coupling constant\nevolves very slowly (walks). We simulate lattice QCD with 2 flavours of sextet\nstaggered quarks to determine whether walks, or if it has an infrared fixed\npoint, making it a conformal field theory. Our initial simulations are\nperformed at finite temperatures $T=1/N_ta$ ($N_t=4$ and $N_t=6$), which allows\nus to identify the scales of confinement and chiral-symmetry breaking from the\ndeconfinement and chiral-symmetry restoring transitions. Unlike QCD with\nfundamental quarks, these two transitions appear to be well-separated. The\nchange in coupling constants at these transitions between the two different\ntemporal extents $N_t$, is consistent with these being finite temperature\ntransitions for an asymptotically free theory, which favours walking behaviour.\nIn the deconfined phase, the Wilson Line shows a 3-state signal. Between the\nconfinement and chiral transitions, there is an additional transition where the\nstates with Wilson Lines oriented in the directions of the complex cube roots\nof unity disorder into a state with a negative Wilson Line."
    },
    {
        "anchor": "Roma versus Zaragoza: The Roma and Zaragoza actions for chiral fermions on the lattice are shown to\nbe essentially equivalent. The auxiliary fermion fields in the Roma model can\nbe integrated out, and the resulting action is a special case of the Zaragoza\napproach. We use this result to perform a mean-field study of the phase diagram\nof chiral Yukawa models in the Roma formulation.",
        "positive": "Effects of spatial size, lattice doubling and source operator on the\n  hadron spectrum with dynamical staggered quarks: We have extended our previous study of the lattice QCD spectrum with 2\nflavors of staggered dynamical quarks at $6/g^2=5.6$ and $am_q=0.025$ and 0.01\nto larger lattices, with better statistics and with additional sources for the\npropagators. The additional sources allowed us to estimate the $\\Delta$ mass\nand to measure the masses of all mesons whose operators are local in time.\nThese mesons show good evidence for flavor symmetry restoration, except for the\nmasses of the Goldstone and non-Goldstone pions. PCAC is observed in that\n$m_\\pi^2 \\propto m_q$, and $f_\\pi$ is estimated. Use of undoubled lattices\nremoves problems with the pion propagator found in our earlier work. Previously\nwe found a large change in the nucleon mass at a quark mass of $am_q=0.01$ when\nwe increased the spatial size from 12 to 16. No such effect is observed at the\nlarger quark mass, $am_q=0.025$. Two kinds of wall source were used, and we\nhave found difficulties in getting consistent results for the nucleon mass\nbetween the two sources."
    },
    {
        "anchor": "Remarks on the reweighting method in the chemical potential direction: We comment on the reweighting method in the chemical potential $(\\mu_{\\rm\nq})$ direction. We study the fluctuation of the reweighting factor during\nMonte-Carlo steps. We find that it is the absolute value of the reweighting\nfactor that mainly contributes to the shift of the phase transition line\n$(\\beta_c)$ by the presence of $\\mu_{\\rm q}$. The phase fluctuation is a cause\nof the sign problem, but the effect on $\\beta_c$ seems to be small. We also\ndiscuss $\\beta_c$ for Iso-vector chemical potential and $\\beta_c$ determined\nfrom simulations with imaginary chemical potential.",
        "positive": "Gauge theory of Lorentz group on the lattice: The model with the fermions coupled in the non - minimal way to the gauge\ntheory of Lorentz group is considered. The lattice regularization is suggested.\nIt is argued that this model may exist in the phase with broken chiral symmetry\nand without confinement. We speculate about the possibility that this\nconstruction may serve as an origin of the dynamical electroweak symmetry\nbreaking."
    },
    {
        "anchor": "An Alternative Lattice Field Theory Formulation Inspired by Lattice\n  Supersymmetry: We propose an unconventional formulation of lattice field theories which is\nquite general, although originally motivated by the quest of exact lattice\nsupersymmetry. Two long standing problems have a solution in this context: 1)\nEach degree of freedom on the lattice corresponds to $2^d$ degrees of freedom\nin the continuum, but all these doublers have (in the case of fermions) the\nsame chirality and can be either identified, thus removing the degeneracy, or,\nin some theories with extended supersymmetry, identified with different members\nof the same supermultiplet. 2) The derivative operator, defined on the lattice\nas a suitable periodic function of the lattice momentum, is an addittive and\nconserved quantity, thus assuring that the Leibnitz rule is satisfied. This\nimplies that the product of two fields on the lattice is replaced by a\nnon-local \"star product\" which is however in general non-associative.\nAssociativity of the \"star product\" poses strong restrictions on the form of\nthe lattice derivative operator (which becomes the inverse gudermannian\nfunction of the lattice momentum) and has the consequence that the degrees of\nfreedom of the lattice theory and of the continuum theory are in one-to-one\ncorrespondence, so that the two theories are eventually equivalent.\nRegularization of the ultraviolet divergences on the lattice is not associated\nto the lattice spacing, which does not act as a regulator, but may be obtained\nby a one parameter deformation of the lattice derivative, thus preserving the\nlattice structure even in the limit of infinite momentum cutoff. However this\nregularization breaks gauge invariance and a gauge invariant regularization\nwithin the lattice formulation is still lacking.",
        "positive": "Finite density phase transition of QCD with $N_f=4$ and $N_f=2$ using\n  canonical ensemble method: In a progress toward searching for the QCD critical point, we study the\nfinite density phase transition of $N_f = 4$ and 2 lattice QCD at finite\ntemperature with the canonical ensemble approach. We develop a winding number\nexpansion method to accurately project out the particle number from the fermion\ndeterminant which greatly extends the applicable range of baryon number sectors\nto make the study feasible. Our lattice simulation was carried out with the\nclover fermions and improved gauge action. For a given temperature, we\ncalculate the baryon chemical potential from the canonical approach to look for\nthe mixed phase as a signal for the first order phase transition. In the case\nof $N_f=4$, we observe an \"S-shape\" structure in the chemical potential-density\nplane due to the surface tension of the mixed phase in a finite volume which is\na signal for the first order phase transition. We use the Maxwell construction\nto determine the phase boundaries for three temperatures below $T_c$. The\nintersecting point of the two extrapolated boundaries turns out to be at the\nexpected first order transition point at $T_c$ with $\\mu = 0$. This serves as a\ncheck for our method of identifying the critical point. We also studied the\n$N_f =2$ case, but do not see a signal of the mixed phase for temperature as\nlow as 0.83 $T_c$."
    },
    {
        "anchor": "Improved Lattice Renormalization Group Techniques: We compute the bare step-scaling function $s_b$ for SU(3) lattice gauge\ntheory with $N_f = 12$ massless fundamental fermions, using the\nnon-perturbative Wilson-flow-optimized Monte Carlo Renormalization Group\ntwo-lattice matching technique. We use a short Wilson flow to approach the\nrenormalized trajectory before beginning RG blocking steps. By optimizing the\nlength of the Wilson flow, we are able to determine an $s_b$ corresponding to a\nunique discrete $\\beta$ function, after a few blocking steps. We carry out this\nstudy using new ensembles of 12-flavor gauge configurations generated with\nexactly massless fermions, using volumes up to $32^4$. The results are\nconsistent with the existence of an infrared fixed point (IRFP) for all\ninvestigated lattice volumes and number of blocking steps. We also compare\ndifferent renormalization schemes, each of which indicates an IRFP at a\nslightly different value of the bare coupling, as expected for an IR-conformal\ntheory.",
        "positive": "Exact Local Bosonic Algorithm for Dynamical Quarks: We present an exact local bosonic algorithm for the simulation of dynamical\nfermions in lattice QCD. We show that this algorithm is a viable alternative to\nthe Hybrid Monte Carlo algorithm."
    },
    {
        "anchor": "Strangeness and glue in the nucleon from lattice QCD: We study the strangeness contribution to nucleon matrix elements using Nf=2+1\ndynamical clover fermion configurations generated by the CP-PACS/JLQCD\ncollaboration. In order to evaluate the disconnected insertion (DI), we use the\nZ(4) stochastic method, along with unbiased subtraction from the hopping\nparameter expansion which reduces the off-diagonal noises in the stochastic\nmethod. Furthermore, we find that using many nucleon sources for each\nconfiguration is effective in improving the signal. Our results for the quark\ncontribution to the first moment <x>_q in the DI, and the strangeness magnetic\nmoment show that the statistical errors are under control with these\ntechniques. We also study the gluonic contribution to the nucleon using the\noverlap operator to construct the gauge field tensor, F_{mu,nu}. The\napplication to the calculation of first moment, <x>_G, gives a good signal in\nquenched lattice QCD.",
        "positive": "The phase diagram of Yang-Mills theory with a compact extra dimension: We present a non-perturbative study of the phase diagram of SU(2) Yang-Mills\ntheory in a five-dimensional spacetime with a compact extra dimension. The\nnon-renormalizable theory is regularized on an anisotropic lattice and\ninvestigated through numerical simulations in a regime characterized by a\nhierarchy between the scale of low-energy physics, the inverse compactification\nradius, and the cutoff scale. We map out the structure of the phase diagram and\nthe pattern of lines corresponding to fixed values of the ratio between the\nmass of the fifth component of the gauge field and the non-perturbative mass\ngap of the four-dimensional modes. We discuss different limits of the model,\nand comment on the implications of our findings."
    },
    {
        "anchor": "Strong isospin breaking with twisted mass lattice QCD: In this work we propose a method for including strong isospin breaking in\ntwisted mass lattice calculations, while preserving flavor identification. We\nutilize a partially quenched construction in which the sea quarks are given by\nthe standard twisted mass lattice action while the valence quarks have an\nadditional strong isospin breaking mass term. This construction allows for a\npractical use with existing twisted-mass gauge ensembles. Additionally, we\nconstruct the relevant partially quenched twisted mass chiral perturbation\ntheory for both mesons and baryons to O(m_q^2, m_q a, a^2). We provide explicit\nexpressions for the pion, nucleon and delta masses, as well as the\ncorresponding mass splittings, and discuss the resulting errors from including\nthe strong isospin breaking in the valence sector only. Finally, we demonstrate\nhow the application of this idea can be used, with mild approximations, to\ndetermine the values of both the up and down quark masses.",
        "positive": "Nucleon Scalar and Tensor Charges from Lattice QCD with Light Wilson\n  Quarks: We present 2+1 flavor Lattice QCD calculations of the nucleon scalar and\ntensor charges. Using the BMW clover-improved Wilson action with pion masses\nbetween 150 and 350 MeV and three source-sink separations between 0.9 and 1.4\nfm, we achieve good control over excited-state contamination and extrapolation\nto the physical pion mass. As a consistency check, we also present results from\ncalculations using unitary domain wall fermions with pion masses between 300\nand 400 MeV, and using domain wall valence quarks and staggered sea quarks with\npion masses between 300 and 600 MeV."
    },
    {
        "anchor": "Mixed Action Effective Field Theory: an Addendum: We correct a mistake in the literature regarding the additive lattice spacing\ncorrections to the mixed valence-sea meson mass and discuss the consequences\nfor mixed action extrapolation formulae.",
        "positive": "Charged Pion Polarizability from the Lattice: Direct evaluation of charged particle polarizabilities on the lattice is\nquite difficult. However, a short cut for charged pion polarizability - the\nDas, Mathur, Okubo Sum Rule - can readily be calculated using lattice\ntechniques. A phenomenological model has been developed to fit the time\nbehavior of the propagators in this expression. Numerical systematics are\ndiscussed and some preliminary results are presented."
    },
    {
        "anchor": "The static quark potential in three flavor QCD: We study the effects of dynamical quarks on the static quark potential at\ndistances shorter than those where string breaking is expected. Quenched\ncalculations and calculations with three flavors of dynamical quarks are done\non sets of lattices with the lattice spacings matched within about one percent.\nThe effect of the sea quarks on the shape of the potential is clearly visible.\nWe investigate the consequences of these effects in a very crude model, namely\nsolving Schroedinger's equation in the resulting potential.",
        "positive": "Fortran MPI Checkerboard Code for SU(3) Lattice Gauge Theory II: We study the performance of MPI checkerboard code for SU(3) lattice gauge\ntheory as function of the number of MPI processes, which run in parallel on an\nidentical number of CPU cores. Computing platforms explored are a small PC\ncluster at FSU and the Cray at NERSC."
    },
    {
        "anchor": "QCD with two flavors of Wilson fermions: The QCD vacuum, the Aoki vacuum\n  and other vacua: We discuss the vacuum structure of QCD with two flavors of Wilson fermions.\nWe derive two possible scenarios: (i) If the spectral density\n$\\rho_U(\\lambda,\\kappa)$ of the overlap hamiltonian in a fixed background gauge\nfield is not symmetric in $\\lambda$, Hermiticity is violated and Hermiticity\nviolation effects could influence numerical determinations of the $\\eta$ meson\nmass if we are not near enough to the continuum limit, where Hermiticity should\nbe recovered; (ii) otherwise we argue that, under certain assumptions, new\nphases appear beside the Aoki phase, which can be characterized by a\nnonvanishing vacuum expectation value of\n$i\\bar\\psi_u\\gamma_5\\psi_u+i\\bar\\psi_d\\gamma_5\\psi_d$, and with vacuum states\nthat cannot be connected with the Aoki vacua by parity-flavor symmetry\ntransformations. Quenched numerical simulations suggest that the second\nscenario is more likely realized.",
        "positive": "Towards Precision B-physics from Non-Perturbative Heavy Quark Effective\n  Theory: We convey an idea of the significant recent progress, which opens up good\nperspectives for high-precision ab-initio computations in heavy flavour physics\nbased on lattice QCD. Rather than surveying the latest results, this\ncontribution focuses on the concept and the challenges of fully\nnon-perturbative computations in the B-meson sector, where the b-quark is\ntreated within an effective theory. We outline its use to determine the b-quark\nmass and report on the results obtained in the quenched approximation and on\nthe status in the two dynamical flavour theory."
    },
    {
        "anchor": "Disconnected quark loop contributions to nucleon observables using\n  $N_f=2$ twisted clover fermions at the physical value of the light quark mass: We compute the disconnected quark loops contributions entering the\ndetermination of nucleon observables, by using a $N_f = 2$ ensemble of twisted\nmass fermions with a clover term at a pion mass $m_\\pi = 133$ MeV. We employ\nexact deflation and implement all calculations in GPUs, enabling us to achieve\nlarge statistics and a good signal.",
        "positive": "Compact lattice formulation of Cho-Faddeev-Niemi decomposition: string\n  tension from magnetic monopoles: In this paper we begin on a new lattice formulation of the non-linear change\nof variables called the Cho--Faddeev--Niemi decomposition in SU(2) Yang-Mills\ntheory. This is a compact lattice formulation improving the non-compact lattice\nformulation proposed in our previous paper. Based on this formulation, we\npropose a new gauge-invariant definition of the magnetic monopole current which\nguarantees the magnetic charge quantization and reproduces the conventional\nmagnetic-current density obtained in the Abelian projection based on the\nDeGrand--Toussaint method. Finally, we demonstrate the magnetic monopole\ndominance in the string tension in SU(2) Yang-Mills theory on a lattice. Our\nformulation enables one to reproduce in the gauge-invariant way remarkable\nresults obtained so far only in the Maximally Abelian gauge."
    },
    {
        "anchor": "Mass Determination from Constraint Effective Potential: The Constraint Effective Potential (CEP) allows a determination of the mass\nand other quantities directly, without relying upon asymptotic correlator\ndecays. We report and discuss the results of some mass calculations in\n$(\\lambda \\Phi^4)_4$, obtained from CEP and our improved version of CEP (ICEP).",
        "positive": "LDIC Survey 2023: Feeling Welcome in the Community: We review the level of welcomeness that members of the lattice field theory\ncommunity feel based on the results of a survey performed in May and June 2023.\nWhile respondents reported generally high levels of feeling welcome at the\nlattice conference, women and people with diverse gender identities, sexual\norientations, ethnic backgrounds and religious affiliations feel less included\nand have more negative experiences at the lattice conference than their peers.\nRespondents report that they are actively informing themselves about inequities\nin the community, however a large fraction of survey participants underestimate\nthe severity of the problem, as was found in previous surveys. The survey data\nindicate that this situation can be most effectively improved by organizing\ntalks and events about issues of diversity and inclusion within the lattice\ncommunity. Respondents also reported that individual readings of scientific\npapers on equity and inclusion are effective in giving people agency in making\na change and hence it may be helpful to collate a collection of important\narticles on these topics."
    },
    {
        "anchor": "Gravity and Random Surfaces on the Lattice - A Review: We review recent work in the lattice approach to random surfaces and quantum\ngravity. Our task is made somewhat easier by some very interesting results,\nparticularly in four dimensions, that have appeared recently and which are\nreported elsewhere in these proceedings. Inevitably, given the scope of the\nreview and the limitations of space, the presentation will omit work of\nimportance and be telegraphic in discussing work that is included, for which\napologies are offered in advance. After the customary brief historical\nintroduction we work our way in dimensional order from one up to four\ndimensions before closing with some remarks on the relation, if any, between\nthe various lattice models and ``real'' 4D gravity.",
        "positive": "(lambda Phi^4)_4 theory on the lattice: evidence for a non-trivial\n  rescaling of the scalar condensate: A lattice simulation in the broken phase of four-dimensional (lambda Phi^4)\ntheory in the Ising limit suggests that, in the continuum limit, the scalar\ncondensate rescales by a factor different from the conventional wavefunction\nrenormalization. Possible effects on the present bounds of the Higgs mass are\ndiscussed."
    },
    {
        "anchor": "From Lattice Strong Dynamics to Phenomenology: We present updated results on the chiral properties of SU(3) gauge theories\nwith 2 and 6 massless Dirac fermions in the fundamental representation. Our\nfocus is on the ratio $\\langle \\bar{\\psi} \\psi \\rangle / F^3$, where $\\langle\n\\bar{\\psi} \\psi \\rangle$ is the chiral condensate and $F$ is the\npseudo-Nambu-Goldstone-boson decay constant. This ratio is of interest in the\ncontext of fermion mass generation within composite Higgs theories. By\nre-expanding certain ratios using next-to-leading-order chiral perturbation\ntheory, we confirm our previous result of significant enhancement of this ratio\nat $N_f = 6$ over $N_f = 2$.",
        "positive": "The Compton Amplitude, lattice QCD and the Feynman-Hellmann approach: A major objective of lattice QCD is the computation of hadronic matrix\nelements. The standard method is to use three-point and four-point correlation\nfunctions. An alternative approach, requiring only the computation of two-point\ncorrelation functions is to use the Feynman-Hellmann theorem. In this talk we\ndevelop this method up to second order in perturbation theory, in a context\nappropriate for lattice QCD. This encompasses the Compton Amplitude (which\nforms the basis for deep inelastic scattering) and hadron scattering. Some\nnumerical results are presented showing results indicating what this approach\nmight achieve."
    },
    {
        "anchor": "Renormalization constants for one-derivative fermion operators in\n  twisted mass QCD: We present perturbative and non-perturbative results on the renormalization\nconstants of the local and one-derivative vector and axial vector operators.\nNon-perturbative results are obtained using the twistedmassWilson fermion\nformulation employing two degenerate dynamical quarks and the tree-level\nSymanzik improved gluon action for pion masses in the range of about 450-260\nMeV and at there values of the lattice spacing, namely 0.055 fm, 0.070 fm and\n0.089 fm. Subtraction of O(a^2) terms is carried out by performing the\nperturbative evaluation of these operators at 1- loop and up to O(a^2). The\nrenormalization conditions are defined in the RI'-MOM scheme, for both\nperturbative and non-perturbative results. The Z-factors, obtained for\ndifferent values of the renormalization scale, are evolved perturbatively to a\nreference scale set by the inverse of the lattice spacing. In addition, they\nare translated to MS-bar at 2 GeV using 3-loop perturbative results for the\nconversion factors.",
        "positive": "Lattice Landau gauge quark propagator at finite temperature: We study the Landau gauge quark propagator, at finite temperature, using\nquenched lattice simulations. Special focus is given to the behaviour of the\nmomentum space form factors across the confinement-deconfinement phase\ntransition."
    },
    {
        "anchor": "Recombination of dyons into calorons in SU(2) lattice fields at low\n  temperatures: By cooling of equilibrium lattice fields at finite temperature in SU(2) gauge\ntheory it has been shown that topological objects (calorons) observed on the\nlattice in the confined phase possess a dyonic substructure which becomes\nvisible under certain circumstances. Here we show that, with decreasing\ntemperature of the equilibrium ensemble, the distribution in the caloron\nparameter space is modified such that the calorons appear non-dissociated into\nconstituent dyons. Still the calorons have nontrivial holonomy which is\ndemonstrated by the Polyakov line behaviour for these configurations. At\nvanishing temperature (on a symmetric lattice) topological lumps obtained by\ncooling possess rotational symmetry in 4D and a characteristic double peak\nstructure of Polyakov lines (defined with respect to temporal and spatial\ndirections) with non-trivial asymptotics.",
        "positive": "The quark mass dependence of the pion mass at infinite N: In planar QCD, in two space time dimensions, the meson eigenvalue equation\nhas a nonlocal structure interpretable as resulting from hidden degrees of\nfreedom. The nonlocality can be reconstructed from the functional form of the\npion mass dependence on quark mass within an expansion starting from a special\none dimensional Schroedinger problem. The one dimensional problem makes the\npion mass depend on the quark mass through a simple quadratic relation which is\nshown to be compatible also with numerical data obtained in four dimensions."
    },
    {
        "anchor": "Surface states and chiral symmetry on the lattice: In a Hamiltonian formalism we study chiral symmetry for lattice Fermions\nformulated in terms of Shockley surface states bound to a wall in an extra\nspatial dimension. For hadronic physics this provides a natural scheme for\ntaking quark masses to zero without requiring a precise tuning of parameters.\nWe illustrate the chiral anomaly as a flow of states in this extra dimension.\nWe discuss two alternatives for extending the picture to a chiral coupling of\ngauge fields to such Fermions; one with a small explicit breaking of gauge\nsymmetry and one one with heavy mirror Fermions.",
        "positive": "The SU(3) running coupling from lattice gluons: We provide numerical results for the running coupling in $SU(3)$ Yang-Mills\ntheory as determined from an analysis of lattice two and three-point gluon\ncorrelation functions. The coupling is evaluated directly, from first\nprinciples, by defining suitable renormalisation constants from the lattice\ntriple gluon vertex and gluon propagator. For momenta larger than 2 GeV, the\ncoupling is found to run according to the 2-loop asymptotic formula. The\ninfluence of lattice artifacts on the results appears negligible within the\nprecision of our measurements, although further work on this point is in\nprogress."
    },
    {
        "anchor": "Computation of masses of quarkonium bound states using heavy quark\n  potentials from lattice QCD: We compute masses of bottomonium and charmonium bound states using a\nSchr\\\"odinger equation with a heavy quark-antiquark potential including $1/m$\nand $1/m^2$ corrections previously derived in potential Non-Relativistic QCD\nand computed with lattice QCD. This is a preparatory step for a future project,\nwhere we plan to take into account similar corrections to study quarkonium\nresonances and tetraquarks above the lowest meson-meson thresholds.",
        "positive": "Flowing Gauge Theories: Finite-Density $QED_{1+1}$: Finite-density calculations in lattice field theory are typically plagued by\nsign problems. A promising way to ameliorate this issue is the holomorphic flow\nequations that deform the manifold of integration for the path integral to\nmanifolds in the complex space where the sign fluctuations are less dramatic.\nWe discuss some novel features of applying the flow equations to gauge theories\nand present results for finite-density $QED_{1+1}$."
    },
    {
        "anchor": "Matrix elements from moments of correlation functions: Momentum-space derivatives of matrix elements can be related to their\ncoordinate-space moments through the Fourier transform. We derive these\nexpressions as a function of momentum transfer $Q^2$ for asymptotic in/out\nstates consisting of a single hadron. We calculate corrections to the finite\nvolume moments by studying the spatial dependence of the lattice correlation\nfunctions. This method permits the computation of not only the values of matrix\nelements at momenta accessible on the lattice, but also the momentum-space\nderivatives, providing {\\it a priori} information about the $Q^2$ dependence of\nform factors. As a specific application we use the method, at a single lattice\nspacing and with unphysically heavy quarks, to directly obtain the slope of the\nisovector form factor at various $Q^2$, whence the isovector charge radius. The\nmethod has potential application in the calculation of any hadronic matrix\nelement with momentum transfer, including those relevant to hadronic weak\ndecays.",
        "positive": "Exploring Correlation Methods to Determine QCD beta-Functions on the\n  Lattice: We investigate -- as an alternative to usual Monte Carlo Renormalization\nGroup methods -- the feasibility of extracting QCD beta-functions directly from\na lattice analysis of correlations between the action and Wilson loops. We test\nthis correlation technique numerically in four dimensional SU(2) gauge theory,\non a 16^4 lattice at beta = 2.5 and find very promising results."
    },
    {
        "anchor": "Aspects of Chiral Symmetry and the Lattice: I explore the non-perturbative issues entwining lattice gauge theory,\nanomalies, and chiral symmetry. After briefly reviewing the importance of\nchiral symmetry in particle physics, I discuss how anomalies complicate lattice\nformulations. Considerable information can be deduced from effective chiral\nLagrangians, helping interpret the expectations for lattice models and\nelucidating the role of the CP violating parameter $\\Theta$. I then turn to a\nparticularly elegant scheme for exploring this physics on the lattice. This\nuses an auxiliary extra space-time dimension, with the physical world being a\nfour dimensional interface.",
        "positive": "The topological properties of QCD at high temperature: problems and\n  perspectives: Lattice computations are the only first principle method capable of\nquantitatively assessing the topological properties of QCD at high temperature,\nhowever the numerical determination of the topological properties of QCD,\nespecially in the high temperature phase, is a notoriously difficult problem.\nWe will discuss the difficulties encountered in such a computation and some\nstrategies that have been proposed to avoid (or at least to alleviate) them."
    },
    {
        "anchor": "Understanding Hadron Structure Using Lattice QCD: Numerical evaluation of the path integral for QCD on a discrete space-time\nlattice has been used to calculate ground state matrix elements specifying\nmoments of quark density and spin distributions. This talk will explain how\nthese matrix elements have been calculated in full QCD using dynamical quarks,\nshow how physical extrapolation to the chiral limit including the physics of\nthe pion cloud resolves previous apparent conflicts with experiment, and\ndescribe the computational resources required for a definitive comparison with\nexperiment.",
        "positive": "Charmed meson decay constants in three-flavor lattice QCD: We present the first lattice QCD calculation with realistic sea quark content\nof the D^+ meson decay constant f_{D^+}. We use the MILC Collaboration's\npublicly available ensembles of lattice gauge fields, which have a quark sea\nwith two flavors (up and down) much lighter than a third (strange). We obtain\nf_{D^+} = 201 +/- 3 +/- 17 MeV, where the errors are statistical and a\ncombination of systematic errors. We also obtain f_{D_s} = 249 +/- 3 +/- 16 MeV\nfor the D_s meson."
    },
    {
        "anchor": "Analytical relation between quark confinement and chiral symmetry\n  breaking in odd-number lattice QCD: To clarify the relation between confinement and chiral symmetry breaking in\nQCD, we consider a temporally odd-number lattice, with the temporal lattice\nsize $N_t$ being odd. We here use an ordinary square lattice with the normal\n(nontwisted) periodic boundary condition for link-variables in the temporal\ndirection. By considering ${\\rm Tr} (\\hat{U}_4\\hat{\\not D}^{N_t-1})$, we\nanalytically derive a gauge-invariant relation between the Polyakov loop\n$\\langle L_P \\rangle$ and the Dirac eigenvalues $\\lambda_n$ in QCD, i.e.,\n$\\langle L_P \\rangle \\propto \\sum_n \\lambda_n^{N_t -1} \\langle n|\\hat U_4|n\n\\rangle$, which is a Dirac spectral representation of the Polyakov loop in\nterms of Dirac eigenmodes $|n\\rangle$. Owing to the factor $\\lambda_n^{N_t -1}$\nin the Dirac spectral sum, this relation generally indicates fairly small\ncontribution of low-lying Dirac modes to the Polyakov loop, while the low-lying\nDirac modes are essential for chiral symmetry breaking. Also in lattice QCD\ncalculations in both confined and deconfined phases, we numerically confirm the\nanalytical relation, non-zero finiteness of $\\langle n|\\hat U_4|n \\rangle$ for\neach Dirac mode, and negligibly small contribution from low-lying Dirac modes\nto the Polyakov loop, i.e., the Polyakov loop is almost unchanged even by\nremoving low-lying Dirac-mode contribution from the QCD vacuum generated by\nlattice QCD simulations. We thus conclude that low-lying Dirac modes are not\nessential modes for confinement, which indicates no direct one-to-one\ncorrespondence between confinement and chiral symmetry breaking in QCD.",
        "positive": "Excited states of massive fermions in a chiral gauge theory: It is shown numerically, in a chiral U(1) gauge Higgs theory in which the\nleft and right-handed fermion components have opposite U(1) charges, that the\nspectrum of gauge and Higgs fields surrounding a static fermion contains both a\nground state and at least one stable excited state. To bypass the difficulties\nassociated with dynamical fermions in a lattice chiral gauge theory we consider\nonly static fermion sources in a quenched approximation, at fixed lattice\nspacing and couplings, and with a lattice action along the lines suggested long\nago by Smit and Swift."
    },
    {
        "anchor": "Renormalisation of composite operators in lattice QCD: perturbative\n  versus nonperturbative: The perturbative and nonperturbative renormalisation of quark-antiquark\noperators in lattice QCD with two flavours of clover fermions is investigated\nwithin the research programme of the QCDSF collaboration. Operators with up to\nthree derivatives are considered. The nonperturbative results based on the\nRI-MOM scheme are compared with estimates from one- and two-loop lattice\nperturbation theory.",
        "positive": "Magnetized baryons and the QCD phase diagram: NJL model meets the\n  lattice: We determine the baryon spectrum of 1 + 1 + 1-flavor QCD in the presence of\nstrong background magnetic fields using lattice simulations at physical quark\nmasses for the first time. Our results show a splitting within multiplets\naccording to the electric charge of the baryons and reveal, in particular, a\nreduction of the nucleon masses for strong magnetic fields. This\nfirst-principles input is used to define constituent quark masses and is\nemployed to set the free parameters of the Polyakov loop-extended\nNambu-Jona-Lasinio (PNJL) model in a magnetic field-dependent manner. The so\nconstructed model is shown to exhibit inverse magnetic catalysis at high\ntemperatures and a reduction of the transition temperature as the magnetic\nfield grows - in line with non-perturbative lattice results. This is contrary\nto the naive variant of this model, which gives incorrect results for this\nfundamental phase diagram. Our findings demonstrate that the magnetic field\ndependence of the PNJL model can be reconciled with the lattice findings in a\nsystematic way, employing solely zero-temperature first-principles input."
    },
    {
        "anchor": "Anisotropic Lattice QCD Studies of Penta-quark Anti-decuplet: Anti-decuplet penta-quark baryon is studied with the quenched anisotropic\nlattice QCD for accurate measurement of the correlator. Both the positive and\nnegative parity states are studied using a non-NK type interpolating field with\nI=0 and J=1/2. After the chiral extrapolation, the lowest positive parity state\nis found at m_{Theta} \\simeq 2.25 GeV, which is too massive to be identified\nwith the experimentally observed Theta^+(1540). The lowest negative parity\nstate is found at m_{Theta}\\simeq 1.75 GeV, which is rather close to the\nempirical value. To confirm that this state is a compact 5Q resonance, a new\nmethod with ``hybrid boundary condition (HBC)'' is proposed. The HBC analysis\nshows that the observed state in the negative parity channel is an NK\nscattering state.",
        "positive": "Excited hadrons on the lattice: Baryons: We present results for masses of excited baryons from a quenched calculation\nwith Chirally Improved quarks at pion masses down to 350 MeV. Our analysis of\nthe correlators is based on the variational method. In order to provide a large\nbasis set for spanning the physical states, we use interpolators with different\nDirac structures and Jacobi smeared quark sources of different width. Our\nspectroscopy results for a wide range of ground state and excited baryons are\ndiscussed."
    },
    {
        "anchor": "Recent progress in lattice calculations of properties of open-charm\n  mesons: Recent progress in lattice calculations of properties of open-charm mesons,\nboth regular and exotic, is reviewed, with an emphasis on spectroscopy. After\nreviewing recent calculations of excited state energy levels I will discuss\nprogress in extracting hadronic masses and widths of charmed states from\nLattice QCD simulations including low-lying scattering channels directly, to\ndetermine phase shift data and bound state/ resonance properties. With regard\nto other properties results from recent calculations of the $DD^*\\pi$ and\n$DD\\rho$, $D^*D^*\\rho$ couplings are presented. Beyond regular mesons, searches\nfor explicitly exotic (tetraquark) states are also reviewed.",
        "positive": "New mixed inhomogeneous phase in vortical gluon plasma: first-principle\n  results from rotating SU(3) lattice gauge theory: Using first-principle numerical simulations, we find a new spatially\ninhomogeneous phase in rigidly rotating $N_c = 3$ gluon plasma. This mixed\nphase simultaneously possesses both confining and deconfining phases in thermal\nequilibrium. Unexpectedly, the local critical temperature of the phase\ntransition at the rotation axis does not depend on the angular frequency within\na few percent accuracy. Even more surprisingly, an analytic continuation of our\nresults to the domain of real angular frequencies indicates a profound breaking\nof the Tolman-Ehrenfest law in the vicinity of the phase transition, with the\nconfining (deconfining) phase appearing far (near) the rotation axis."
    },
    {
        "anchor": "Lattice study of pion-pion scattering using Nf=2+1 Wilson improved\n  quarks with masses down to their physical values: We use 2HEX smeared gauge configurations generated with an\n$\\mathrm{N}_\\mathrm{f}\\mathrm{=2+1}$ clover improved Wilson action to\ninvestigate $\\pi\\pi$ scattering in the $\\rho$ channel. The range of lattice\nspacings (0.054 to 0.12 fm) and space-like extents (32 and 48) allows us to\nextract the scattering parameters through the volume dependence of the\n$\\pi\\pi$-state energies according to L\\\"uscher's formalism. The pion masses\n(134 to 300 MeV) are light enough to allow the decay of the rho and the level\nrepulsion observed indicates that our data are sensitive to the interaction. We\nanalyse our data with a multi-channel GEVP variational formula. Our results are\nin good agreement with the experimental values and consistent with a weak pion\nmass dependence of the $\\rho\\pi\\pi$ coupling constant.",
        "positive": "Finite Volume Dependence of the Quark-Antiquark Vacuum Expectation Value: A general formula is derived for the finite volume dependence of vacuum\nexpectation values analogous to Luscher's formula for the masses. The result\ninvolves no integrals over kinematic quantities and depends only on the matrix\nelement between pions at zero momentum transfer thus presenting a new way to\ncalculate the latter, i.e. pion sigma terms.\n  The full order $p^6$ correction to the vacuum condensate $<\\bar q q>$ is\nevaluated and compared with the result from the Luscher formula. Due to the\nsize of the $p^6$ result no conclusion about the accuracy of the Luscher\nformula can be drawn."
    },
    {
        "anchor": "Pseudoscalar Mass and Decay Constant in Lattice QCD with Exact Chiral\n  Symmetry: The masses and decay constants of pseudoscalar mesons $ D $, $ D_s $, and $ K\n$ are determined in quenched lattice QCD with exact chiral symmetry. For 100\ngauge configurations generated with single-plaquette action at $ \\beta = 6.1 $\non the $ 20^3 \\times 40 $ lattice, we compute point-to-point quark propagators\nfor 30 quark masses in the range $ 0.03 \\le m_q a \\le 0.80 $, and measure the\ntime-correlation functions of pseudoscalar and vector mesons. The inverse\nlattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\\pi\n$, while the strange quark bare mass ($ m_s a = 0.08 $), and the charm quark\nbare mass ($ m_c a = 0.80 $) are fixed such that the masses of the\ncorresponding vector mesons are in good agreement with $ \\phi(1020) $ and $\nJ/\\psi(3097) $ respectively. Our results of pseudoscalar-meson decay constant\nare: $ f_K = 152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} =\n266(10)(18) $ MeV [hep-ph/0506266]. The latest experimental result of $ f_{D^+}\n$ from CLEO [hep-ex/0508057] is in good agreement with our prediction.",
        "positive": "Reweighting Lefschetz Thimbles: We present a novel reweighting technique to calculate the relative weights in\nthe Lefschetz thimble decomposition of a path integral. Our method is put to\nwork using a $U(1)$ one-link model providing for a suitable testing ground and\nsharing many features with realistic gauge theories with fermions at finite\ndensity. We discuss prospects and future challenges to our method."
    },
    {
        "anchor": "LQCD at non zero isospin chemical potential: Systems of non-zero isospin chemical potential are studied from a canonical\napproach by computing correlation functions with the quantum numbers of $N\n\\pi^+$'s ($C_{N \\pi}$). In order to reduce the number of contractions required\nin calculating $C_{N \\pi}$ for a large $N$ in the Wick's theorem, we\nconstructed a few new algorithms. With these new algorithms, systems with\nisospin charge up to 72 are investigated on three anisotropic gauge ensembles\nwith a pion mass of $390 \\rm{MeV}$, and with lattice spatial extents $L \\sim\n{2.0, 2.5, 3.0} \\rm{fm}$. The largest isospin density of $\\rho_I \\approx 9\n\\rm{fm}^{-3}$ is achieved in the smallest volume, and the QCD phase diagram is\ninvestigated at a fixed low temperature at varying isospin chemical potentials,\n$m_{\\pi} \\le \\mu_I \\le 4.5 m_{\\pi}$. By investigating the behaviour of the\nextracted energy density of the system at different isospin chemical\npotentials, we numerically identified the conjectured transition to a\nBose-Einstein condensation state at $\\mu_I \\ge m_{\\pi}$.",
        "positive": "Quark propagators at finite temperature with the clover action: We study properties of the finite temperature quark propagator by using the\nSU(3) quenched lattice simulation in the Landau gauge and report numerical\nresults of the standard Wilson quark case as well as the improved clover one.\nThe mass function in the deconfinement phase is different from that of the\nconfinement phase, especially at low momentum regions."
    },
    {
        "anchor": "Electromagnetic splitting of quark and pseudoscalar meson masses from\n  dynamical QCD + QED: Lattice QCD simulations are now reaching a precision where electromagnetic\ncorrections from QED become important. In investigating the effects of SU(3)\nbreaking due to quark mass differences within QCD, a group-theoretical analysis\nof the mass dependence greatly helped us organize our results. We now do the\nsame with electromagnetic charge effects by extending the calculations to\ndynamical 1+1+1 flavor QCD + QED.",
        "positive": "Dual Higgs Theory for Color Confinement in Quantum Chromodynamics: Based on the dual superconductor picture, we study the confinement phenomena\nsystematically, using the lattice QCD, the monopole-current dynamics and the\ndual Ginzburg-Landau (DGL) theory. (1) We study the origin of abelian dominance\nfor the confinement force in the maximally abelian (MA) gauge in terms of the\ngluon-field properties using the lattice QCD. In the MA gauge, the off-diagonal\ngluon amplitude is strongly suppressed, and the off-diagonal gluon phase tends\nto be random, according to the weakness of the constraint from the QCD action.\nWithin the random-variable approximation for the off-diagonal gluon phase, we\nshow the perimeter law of the off-diagonal gluon contribution to the Wilson\nloop, i.e. abelian dominance for the string tension, in the semi-analytical\nmanner. (2) We study the QCD-monopole structure in terms of the gluon field,\nusing the lattice QCD in the MA gauge. Around the monopole, both abelian and\noff-diagonal parts of the QCD action become large, however, due to the\ncancellation between them, monopoles can appear in QCD without large cost of\nthe QCD action. (3) We derive a simple relation between the confinement force\nand the monopole density by idealizing the monopole contribution to the Wilson\nloop. (4) We study the monopole current dynamics. (5) We consider the\nderivation of the DGL theory from the monopole ensemble. (6) We study the QCD\nphase transition at finite temperatures in the DGL theory. (7) We apply the DGL\ntheory for the hadron-bubble formation in early Universe and quark-gluon-plasma\nformation process in the ultra-relativistic heavy-ion collision."
    },
    {
        "anchor": "Sampling U(1) gauge theory using a re-trainable conditional flow-based\n  model: Sampling topological quantities in the Monte Carlo simulation of Lattice\nGauge Theory becomes challenging as we approach the continuum limit of the\ntheory. In this work, we introduce a Conditional Normalizing Flow (C-NF) model\nto sample U(1) gauge theory in two dimensions, aiming to mitigate the impact of\ntopological freezing when dealing with smaller values of the U(1) bare\ncoupling. To train the conditional flow model, we utilize samples generated by\nHybrid Monte Carlo (HMC) method, ensuring that the autocorrelation in\ntopological quantities remains low. Subsequently, we employ the trained model\nto interpolate the coupling parameter to values where training was not\nperformed. We thoroughly examine the quality of the model in this region and\ngenerate uncorrelated samples, significantly reducing the occurrence of\ntopological freezing. Furthermore, we propose a re-trainable approach that\nutilizes the model's own samples to enhance the generalization capability of\nthe conditional model. This method enables sampling for coupling values that\nare far beyond the initial training region, expanding the applicability of the\nmodel.",
        "positive": "Non-Gaussianities in the topological charge distribution of the SU(3)\n  Yang--Mills theory: We study the topological charge distribution of the SU(3) Yang--Mills theory\nwith high precision in order to be able to detect deviations from Gaussianity.\nThe computation is carried out on the lattice with high statistics Monte Carlo\nsimulations by implementing a naive discretization of the topological charge\nevolved with the Yang--Mills gradient flow. This definition is far less\ndemanding than the one suggested from Neuberger's fermions and, as shown in\nthis paper, in the continuum limit its cumulants coincide with those of the\nuniversal definition appearing in the chiral Ward identities. Thanks to the\nrange of lattice volumes and spacings considered, we can extrapolate the\nresults for the second and fourth cumulant of the topological charge\ndistribution to the continuum limit with confidence by keeping finite volume\neffects negligible with respect to the statistical errors. Our best results for\nthe topological susceptibility is t_0^2*chi=6.67(7)*10^-4, where t_0 is a\nstandard reference scale, while for the ratio of the forth cumulant over the\nsecond we obtain R=0.233(45). The latter is compatible with the expectations\nfrom the large Nc expansion, while it rules out the theta-behavior of the\nvacuum energy predicted by the dilute instanton model. Its large distance from\n1 implies that, in the ensemble of gauge configurations that dominate the path\nintegral, the fluctuations of the topological charge are of quantum\nnon-perturbative nature."
    },
    {
        "anchor": "Non-perturbative calculation of $Z_V$ and $Z_A$ in domain-wall QCD on a\n  finite box: We report on a non-perturbative evaluation of the renormalization factors for\nthe vector and axial-vector currents, $Z_V$ and $Z_A$, in the quenched\ndomain-wall QCD (DWQCD) with plaquette and renormalization group improved gauge\nactions. We take the Dirichlet boundary condition for both gauge and\ndomain-wall fermion fields on the finite box, and introduce the flavor-chiral\nWard-Takahashi identities to calculate the renormalization factors. As a test\nof the method, we numerically confirm the expected relation that $Z_V \\simeq\nZ_A$ in DWQCD. Employing two different box sizes for the numerical simulations\nat several values of the gauge coupling constant $g^2$ and the domain-wall\nheight $M$, we extrapolate $Z_V$ to the infinite volume to remove $a/L$ errors.\nWe finally give the interpolation formula of $Z_V$ in the infinite volume as a\nfunction of $g^2$ and $M$.",
        "positive": "Perturbation Calculation of the Axial Anomaly of a Ginsparg-Wilson\n  lattice Dirac operator: A recent proposal suggests that even if a Ginsparg-Wilson lattice Dirac\noperator does not possess any topological zero modes in\ntopologically-nontrivial gauge backgrounds, it can reproduce correct axial\nanomaly for sufficiently smooth gauge configurations, provided that it is\nexponentially-local, doublers-free, and has correct continuum behavior. In this\npaper, we calculate the axial anomaly of this lattice Dirac operator in weak\ncoupling perturbation theory, and show that it recovers the topological charge\ndensity in the continuum limit."
    },
    {
        "anchor": "End Point of a First-Order Phase Transition in Many-Flavor Lattice QCD\n  at Finite Temperature and Density: Towards the feasibility study of the electroweak baryogenesis in realistic\ntechnicolor scenario, we investigate the phase structure of (2+Nf)-flavor QCD,\nwhere the mass of two flavors is fixed to a small value and the others are\nheavy. For the baryogenesis, an appearance of a first order phase transition at\nfinite temperature is a necessary condition. Using a set of configurations of\ntwo-flavor lattice QCD and applying the reweighting method, the effective\npotential defined by the probability distribution function of the plaquette is\ncalculated in the presence of additional many heavy flavors. Through the shape\nof the effective potential, we determine the critical mass of heavy flavors\nseparating the first order and crossover regions and find it to become larger\nwith Nf. We moreover study the critical line at finite density and the first\norder region is found to become wider as increasing the chemical potential.\nPossible applications to real (2+1)-flavor QCD are discussed.",
        "positive": "QCD with zero, two and four flavors of light quarks - results from QCDSP: We present the results from full QCD simulations with four flavors of light\nstag gered dynamical quarks on {\\it {\\it QCDSP}} supercomputer. Previous\nresults are reproduced and the simulation reported here yields new results\nconsistent with o ur previous runs. The hadron spectrum obtained with Wilson\nvalence fermions reported here will allow us to determine if our earlier\nconclusions are independent of lattice form alism."
    },
    {
        "anchor": "Determining Lines of Constant Physics in the Confinement Phase of the\n  SU(2) Higgs Model: We present a method for finding lines of constant physics in the confinement\nphase of the SU(2) Higgs model on the lattice. The model is considered at\nfinite values of the cut-off where it behaves like an effective field theory\nwith three independent couplings. In particular, a renormalised quantity\nsensitive to a variation of the bare Higgs quartic self-coupling is constructed\nfrom generalised Binder cumulants. Numerical results for the non-perturbative\nmatching of the bare parameters of the model between beta=2.2 and beta=2.4 are\npresented.",
        "positive": "Squared width and profile of the confining flux tube in the U(1) LGT in\n  3D: The dual formulation of the compact U(1) lattice gauge theory in three\nspacetime dimensions allows to finely study the squared width and the profile\nof the confining flux tube on a wide range of physical interquark distances.\nThe results obtained in Monte Carlo simulations are compared with the\npredictions of the effective bosonic-string model and with the dual\nsuperconductor model. While the former fails at describing the data from a\nquantitative point of view, the latter is in good agreement with it. An\ninterpretation of these results is proposed in light of the particular features\nof the U(1) lattice gauge theory in 3D and a comparison with non-Abelian gauge\ntheories in four spacetime dimensions is discussed."
    },
    {
        "anchor": "Charge Symmetry Violation in the Electromagnetic Form Factors of the\n  Proton: Experimental tests of QCD through its predictions for the strange-quark\ncontent of the proton have been drastically restricted by our lack of knowledge\nof the violation of charge symmetry (CSV). We find unexpectedly tiny CSV in the\nproton's electromagnetic form factors by performing the first extraction of\nthese quantities based on an analysis of lattice QCD data. The resulting values\nare an order of magnitude smaller than current bounds on proton strangeness\nfrom parity violating electron-proton scattering experiments. This result paves\nthe way for a new generation of experimental measurements of the proton's\nstrange form factors to challenge the predictions of QCD.",
        "positive": "Non-commutative Differential Calculus and the Axial Anomaly in Abelian\n  Lattice Gauge Theories: The axial anomaly in lattice gauge theories has a topological nature when the\nDirac operator satisfies the Ginsparg-Wilson relation. We study the axial\nanomaly in Abelian gauge theories on an infinite hypercubic lattice by\nutilizing cohomological arguments. The crucial tool in our approach is the\nnon-commutative differential calculus~(NCDC) which makes the Leibniz rule of\nexterior derivatives valid on the lattice. The topological nature of the\n``Chern character'' on the lattice becomes manifest in the context of NCDC. Our\nresult provides an algebraic proof of L\\\"uscher's theorem for a\nfour-dimensional lattice and its generalization to arbitrary dimensions."
    },
    {
        "anchor": "Weak Matrix Elements of Beyond the Standard Model $\u0394s=2$\n  four-quark operators from nf=2+1 Domain-Wall fermions: We report on our computation of the hadronic matrix elements of the\nfour-quark operators needed for the study of $K^0-{\\bar K^0}$ mixing beyond the\nStandard Model (SM). We consider nf=2+1 Domain-Wall fermions on Iwasaki gauge\naction with lightest unitary pion of 290 MeV and a single lattice spacing\na=0.086 fm. The renormalization is performed non-perturbatively through the\nRI-MOM scheme and our results are converted perturbatively to MSbar. We have\nestimated the various systematic errors. Our results confirm a previous\nquenched study, where large ratios of non-SM to SM matrix elements were\nobtained.",
        "positive": "New critical phenomena in 2d quantum gravity: We study $q=10$ and $q=200$ state Potts models on dynamical triangulated\nlattices and demonstrate that these models exhibit continuous phase\ntransitions, contrary to the first order transition present on regular\nlattices. For $q=10$ the transition seems to be of 2nd order, while it seems to\nbe of 3rd order for $q=200$. For $q=200$ the phase transition also induces a\ntransition between typical fractal structures of the piecewise linear surfaces\ncorresponding to the triangulations. The typical surface changes from having a\ntree-like structure to a fractal structure characterizing pure gravity when the\ntemperature drops below the critical temperature. An investigation of the\nalignment of spin clusters shows that they are strongly correlated to the\nunderlying fractal structure of the triangulated surfaces."
    },
    {
        "anchor": "Interrelation of a Z(3) Gauge Theory on the Flat Lattices and a Spin-1\n  BEG Model: The Z(3) gauge model with double plaquette representation of the action on\nthe flat triangular and square lattices is constructed. It is reduced to the\nspin-1 Blume-Emery-Griffiths (BEG) model. An Ising-type critical line of a\nsecond-order phase transition is found.",
        "positive": "Lattice supersymmetry in 1D with two supercharges: A consistent formulation of a fully supersymmetric theory on the lattice has\nbeen a long standing challenge. In recent years there has been a renewed\ninterest on this problem with different approaches. At the basis of the\nformulation we present in the following there is the Dirac-Kahler twisting\nprocedure, which was proposed in the continuum for a number of theories,\nincluding N=4 SUSY in four dimensions. Following the formalism developed in\nrecent papers, an exact supersymmetric theory with two supercharges on a one\ndimensional lattice is realized using a matrix-based model. The matrix\nstructure is obtained from the shift and clock matrices used in two dimensional\nnon-commutative field theories. The matrix structure reproduces on a one\ndimensional lattice the expected modified Leibniz rule. Recent claims of\ninconsistency of the formalism are discussed and shown not to be relevant."
    },
    {
        "anchor": "Nucleon-nucleon interactions via Lattice QCD: Methodology --HAL QCD\n  approach to extract hadronic interactions in lattice QCD--: We review the potential method in lattice QCD, which has recently been\nproposed to extract nucleon-nucleon interactions via numerical simulations. We\nfocus on the methodology of this approach by emphasizing the strategy of the\npotential method, the theoretical foundation behind it, and special numerical\ntechniques. We compare the potential method with the standard finite volume\nmethod in lattice QCD, in order to make pros and cons of the approach clear. We\nalso present several numerical results for the nucleon-nucleon potentials.",
        "positive": "Decays of an exotic $1^{-+}$ hybrid meson resonance in QCD: We present the first determination of the hadronic decays of the lightest\nexotic $J^{PC}=1^{-+}$ resonance in lattice QCD. Working with SU(3) flavor\nsymmetry, where the up, down and strange quark masses approximately match the\nphysical strange-quark mass giving $m_\\pi \\sim 700$ MeV, we compute\nfinite-volume spectra on six lattice volumes which constrain a scattering\nsystem featuring eight coupled channels. Analytically continuing the scattering\namplitudes into the complex energy plane, we find a pole singularity\ncorresponding to a narrow resonance which shows relatively weak coupling to the\nopen pseudoscalar--pseudoscalar, vector--pseudoscalar and vector--vector decay\nchannels, but large couplings to at least one kinematically-closed\naxial-vector--pseudoscalar channel. Attempting a simple extrapolation of the\ncouplings to physical light-quark mass suggests a broad $\\pi_1$ resonance\ndecaying dominantly through the $b_1 \\pi$ mode with much smaller decays into\n$f_1 \\pi$, $\\rho \\pi$, $\\eta' \\pi$ and $\\eta \\pi$. A large total width is\npotentially in agreement with the experimental $\\pi_1(1564)$ candidate state,\nobserved in $\\eta \\pi$, $\\eta' \\pi$, which we suggest may be heavily suppressed\ndecay channels."
    },
    {
        "anchor": "Perfect Lattice Actions for Staggered Fermions: We construct a perfect lattice action for staggered fermions by blocking from\nthe continuum. The locality, spectrum and pressure of such perfect staggered\nfermions are discussed. We also derive a consistent fixed point action for free\ngauge fields and discuss its locality as well as the resulting static\nquark-antiquark potential. This provides a basis for the construction of\n(classically) perfect lattice actions for QCD using staggered fermions.",
        "positive": "Lattice QCD at non-zero temperature and density: Soon after the formulation of Quantum Chromodynamics in 1972 its\nregularization on Euclidean space-time lattices had been introduced by Kenneth\nWilson. This paved ground for numerical studies of non-perturbative aspects of\nQCD, first shown by Michael Creutz. Ever since these first lattice QCD\ncalculations the exploration of the QCD phase diagram and the thermodynamics of\nstrong-interaction matter at non-zero temperature and density was pursued\nvigorously. In this brief review I try to highlight some of the results on QCD\nthermodynamics obtain during the last 42 years through lattice QCD\ncalculations."
    },
    {
        "anchor": "Topological susceptibility from the twisted mass Dirac operator spectrum: We present results of our computation of the topological susceptibility with\n$N_f=2$ and $N_f=2+1+1$ flavours of maximally twisted mass fermions, using the\nmethod of spectral projectors. We perform a detailed study of the quark mass\ndependence and discretization effects. We make an attempt to confront our data\nwith chiral perturbation theory and extract the chiral condensate from the\nquark mass dependence of the topological susceptibility. We compare the value\nwith the results of our direct computation from the slope of the mode number.\nWe emphasize the role of autocorrelations and the necessity of long Monte Carlo\nruns to obtain results with good precision. We also show our results for the\nspectral projector computation of the ratio of renormalization constants\n$Z_P/Z_S$.",
        "positive": "The spectrum of lattice QCD with staggered fermions at strong coupling: Using 4 flavors of staggered fermions at infinite gauge coupling, we compare\nvarious analytic results for the hadron spectrum with exact Monte Carlo\nsimulations. Agreement with Ref. \\cite{Martin_etal} is very good, at the level\nof a few percent.\n  Our results give credence to a discrepancy between the baryon mass and the\ncritical chemical potential, for which baryons fill the lattice at zero\ntemperature and infinite gauge coupling. Independent determinations of the\nlatter set it at about 30% less than the baryon mass. One possible explanation\nis that the nuclear attraction becomes strong at infinite gauge coupling."
    },
    {
        "anchor": "Real photon emissions in leptonic decays: We present a non-perturbative calculation of the form factors which\ncontribute to the amplitudes for the radiative decays $P\\to \\ell \\bar \\nu_\\ell\n\\gamma$, where $P$ is a pseudoscalar meson and $\\ell$ is a charged lepton.\nTogether with the non-perturbative determination of the virtual photon\ncorrections to the processes $P\\to \\ell \\bar \\nu_\\ell$, this will allow\naccurate predictions to be made at $O(\\alpha_{em})$ for leptonic decay rates\nfor pseudoscalar mesons ranging from the pion to the $B$ meson. We are able to\nseparate unambiguously the point-like contribution, the square of which leads\nto the infrared divergence in the decay rate, from the structure dependent,\ninfrared-safe, terms in the amplitude. The fully non-perturbative, $O(a)$\nimproved calculation of the inclusive leptonic decay rates will lead to\nsignificantly improved precision in the determination of the corresponding\nCabibbo-Kobayashi-Maskawa (CKM) matrix elements. Precise predictions for the\nemission of a hard photon are also very interesting, especially for the decays\nof heavy $D$ and $B$ mesons for which currently only model-dependent\npredictions are available to compare with existing experimental data.",
        "positive": "Nucleon matrix elements from lattice QCD with all-mode-averaging and a\n  domain-decomposed solver: an exploratory study: We study the performance of all-mode-averaging (AMA) when used in conjunction\nwith a locally deflated SAP-preconditioned solver, determining how to optimize\nthe local block sizes and number of deflation fields in order to minimize the\ncomputational cost for a given level of overall statistical accuracy. We find\nthat AMA enables a reduction of the statistical error on nucleon charges by a\nfactor of around two at the same cost when compared to the standard method. As\na demonstration, we compute the axial, scalar and tensor charges of the nucleon\nin $N_f=2$ lattice QCD with non-perturbatively O(a)-improved Wilson quarks,\nusing O(10,000) measurements to pursue the signal out to source-sink\nseparations of $t_s\\sim 1.5$ fm. Our results suggest that the axial charge is\nsuffering from a significant amount (5-10%) of excited-state contamination at\nsource-sink separations of up to $t_s\\sim 1.2$ fm, whereas the excited-state\ncontamination in the scalar and tensor charges seems to be small."
    },
    {
        "anchor": "Flavor decomposition for the proton helicity parton distribution\n  functions: We present, for the first time, an \\textit{ab initio} calculation of the\nindividual up, down and strange quark helicity parton distribution functions\nfor the proton. The calculation is performed within the twisted mass\nclover-improved fermion formulation of lattice QCD using one ensemble of\ndynamical up, down, strange and charm quarks with a pion mass of 260 MeV. The\nlattice matrix elements are non-perturbatively renormalized and the final\nresults are presented in the $\\overline{ \\rm MS}$ scheme at a scale of 2 GeV.\nWe give results on the $\\Delta u^+(x)$ and $\\Delta d^+(x)$, including\ndisconnected quark loop contributions, as well as on the $\\Delta s^+(x)$. For\nthe latter we achieve unprecedented precision compared to the phenomenological\nestimates.",
        "positive": "Implementing the three-particle quantization condition including higher\n  partial waves: We present an implementation of the relativistic three-particle quantization\ncondition including both $s$- and $d$-wave two-particle channels. For this, we\ndevelop a systematic expansion about threshold of the three-particle\ndivergence-free K matrix, $\\mathcal{K}_{\\mathrm{df,3}}$, which is a\ngeneralization of the effective range expansion of the two-particle K matrix,\n$\\mathcal{K}_2$. Relativistic invariance plays an important role in this\nexpansion. We find that $d$-wave two-particle channels enter first at quadratic\norder. We explain how to implement the resulting multichannel quantization\ncondition, and present several examples of its application. We derive the\nleading dependence of the threshold three-particle state on the two-particle\n$d$-wave scattering amplitude, and use this to test our implementation. We show\nhow strong two-particle $d$-wave interactions can lead to significant effects\non the finite-volume three-particle spectrum, including the possibility of a\ngeneralized three-particle Efimov-like bound state. We also explore the\napplication to the $3\\pi^+$ system, which is accessible to lattice QCD\nsimulations, where we study the sensitivity of the spectrum to the components\nof $\\mathcal{K}_{\\mathrm{df,3}}$. Finally, we investigate the circumstances\nunder which the quantization condition has unphysical solutions."
    },
    {
        "anchor": "The ratio m_c/m_s with Wilson fermions: We determine the quark mass ratio m_c/m_s on the lattice, using Wilson-type\nfermions. Configurations with N_f=2 dynamical clover-improved fermions by the\nQCDSF collaboration are used, which were made available through the ILDG. In\nthe valence sector we use a sophisticated, mass-independently O(a)-improved\nWilson-type action with small cut-off effects even in the charm mass region.\nAfter an extrapolation to the physical pion mass, to zero lattice spacing and\nto infinite box volume, we find m_c/m_s=11.27(30)(26).",
        "positive": "A lattice study of a chirally invariant Higgs-Yukawa model including a\n  higher dimensional $\u03a6^6$-term: We discuss the non-thermal phase structure of a chirally invariant\nHiggs-Yukawa model on the lattice in the presence of a higher dimensional\n$\\Phi^6$-term. For the exploration of the phase diagram we use analytical,\nlattice perturbative calculations of the constraint effectice potential as well\nas numerical simulations. We also present first results of the effects of the\n$\\Phi^6$-term on the lower Higgs boson mass bounds."
    },
    {
        "anchor": "Quenched scalar meson correlator with Domain Wall Fermions: We study the singlet and non-singlet scalar-meson masses using domain wall\nfermions and the quenched approximation. The singlet mass is found to be\nsmaller than the non-singlet mass and indicates that the lowest singlet meson\nstate could be lighter than 1 GeV. The two-point functions for very small quark\nmasses are compared with expectations from the small-volume chiral perturbation\ntheory and the presence of fermionic zero modes.",
        "positive": "An Experimenter's View of Lattice QCD: Lattice QCD has the potential this decade to maximize the sensitivity of the\nentire flavor physics program to new physics and pave the way for understanding\nphysics beyond the Standard Model at the LHC in the coming decade. However, the\nchallenge for the Lattice is to demonstrate reliability at the level of a few\nper cent given a past history of 10-20% errors. The CLEO-c program at the\nCornell Electron Storage Ring is providing the data that will make the\ndemonstration possible."
    },
    {
        "anchor": "Numerical study of the $2+1d$ Thirring model with U($2N$)-invariant\n  fermions: In 2+1 dimensions the global U($2N$) symmetry associated with massless Dirac\nfermions is broken to U($N)\\otimes$U($N$) by a parity-invariant mass. I will\nshow how to adapt the domain wall formulation to recover the U($2N$)-invariant\nlimit in interacting fermion models as the domain wall separation is increased.\nIn particular, I will focus on the issue of potential dynamical mass generation\nin the Thirring model, postulated to take place for $N$ less than some critical\n$N_c$. I will present results of simulations of the model using both HMC\n($N=2$) and RHMC ($N=1$) algorithms, and show that the outcome is very\ndifferent from previous numerical studies of the model made with staggered\nfermions, where the corresponding pattern of symmetry breaking is distinct.",
        "positive": "Finite-Volume Scaling of the Wilson-Dirac Operator Spectrum: The microscopic spectral density of the Hermitian Wilson-Dirac operator is\ncomputed numerically in quenched lattice QCD. We demonstrate that the results\ngiven for fixed index of the Wilson-Dirac operator can be matched by the\npredictions from Wilson chiral perturbation theory. We test successfully the\nfinite volume and the mass scaling predicted by Wilson chiral perturbation\ntheory at fixed lattice spacing."
    },
    {
        "anchor": "Non-perturbative improvement of the axial current for dynamical Wilson\n  fermions: A non-perturbative determination of the axial current improvement coefficient\ncA is performed with two flavors of dynamical improved Wilson fermions and\nplaquette gauge action. The improvement condition is formulated with\nSchroedinger functional boundary conditions and enforced at constant physical\nvolume. Large sensitivity is obtained by using two different pseudo-scalar\nstates in the PCAC relation. We estimate the resulting correction to F_PS at\nbeta=5.2 to be around 10%.",
        "positive": "Toward numerical and analytical studies of first order phase transitions: Discrete lattice simulations of an one-dimensional phi^4 theory coupled to an\nexternal heat bath are being carried out. Great care is taken to remove the\neffects of lattice discreteness and finite size and to establish the correct\ncorrespondence between simulations and the desired, finite-temperature\ncontinuum limit."
    },
    {
        "anchor": "Complex-Temperature Singularities of the Susceptibility in the $d=2$\n  Ising Model. I. Square Lattice: We investigate the complex-temperature singularities of the susceptibility of\nthe 2D Ising model on a square lattice. From an analysis of low-temperature\nseries expansions, we find evidence that as one approaches the point $u=u_s=-1$\n(where $u=e^{-4K}$) from within the complex extensions of the FM or AFM phases,\nthe susceptibility has a divergent singularity of the form $\\chi \\sim\nA_s'(1+u)^{-\\gamma_s'}$ with exponent $\\gamma_s'=3/2$. The critical amplitude\n$A_s'$ is calculated. Other critical exponents are found to be\n$\\alpha_s'=\\alpha_s=0$ and $\\beta_s=1/4$, so that the scaling relation\n$\\alpha_s'+2\\beta_s+\\gamma_s'=2$ is satisfied. However, using exact results for\n$\\beta_s$ on the square, triangular, and honeycomb lattices, we show that\nuniversality is violated at this singularity: $\\beta_s$ is lattice-dependent.\nFinally, from an analysis of spin-spin correlation functions, we demonstrate\nthat the correlation length and hence susceptibility are finite as one\napproaches the point $u=-1$ from within the symmetric phase. This is confirmed\nby an explicit study of high-temperature series expansions.",
        "positive": "Nonperturbative investigation of the diquark potential: We perform an investigation of the static quark-quark-potential both in the\nconfined and the deconfined phase. We discuss conceptual and technical problems\nand present first results of an exploratory numerical investigation."
    },
    {
        "anchor": "The search for new physics in $B \\to K \\ell^+\\ell^-$ and $B \\to K\n  \u03bd\\bar\u03bd$ using precise lattice QCD form factors: We present HPQCD's improved scalar, vector and tensor form factors for $B \\to\nK$ semileptonic decays, using the heavy-HISQ formalism for more accurate\nnormalisation of the weak currents. Working with masses close to the physical\n$b$ on the finest ensemble and including three ensembles with physical light\nquarks, we cover the full physical $q^2$ range with good precision. Our\nuncertainties at $q^2=0$ are a factor of three better than earlier work.\n  We compare Standard Model observables using our form factors to experimental\nmeasurements for the rare flavour changing neutral current processes $B \\to K\n\\ell^+\\ell^-$ and $B \\to K \\nu\\bar{\\nu}$ and discuss the significance of the\ntensions that arise.",
        "positive": "The Isgur-Wise function on the lattice: The h+, h_A1 form factors for the semi-leptonic B->D and B->D* decays are\nevaluated in quenched lattice QCD with beta=6.2. The action and the operators\nare fully O(a) non-perturbatively improved. The Isgur-Wise function is\nevaluated and fitted to extract its slope; the latter is found to be\nrho^2=1.1(2)(3) from the B->D* decay and rho^2=1.0(2)(3) from the B->D decay.\nThe form factors ratios R_1, R_2 are evaluated and found to be in agreement\nwith experimental determinations."
    },
    {
        "anchor": "Spectrum and mass anomalous dimension of SU(2) gauge theories with\n  fermions in the adjoint representation: from $N_f=1/2$ to $N_f=2$: We summarize our results concerning the spectrum and mass anomalous dimension\nof SU(2) gauge theories with various numbers of fermions in the adjoint\nrepresentation, where each Majorana fermion corresponds effectively to half a\nDirac flavour $N_f$. The most relevant examples for extensions of the standard\nmodel are supersymmetric Yang-Mills theory ($N_f=1/2$) and Minimal Walking\nTechnicolour ($N_f=2$). In addition to these theories we will also consider the\ncases of $N_f=1$ and $N_f=3/2$. The results comprise the particle spectrum of\nglueballs, triplet and singlet mesons, and possible fractionally charged spin\nhalf particles. In addition we will discuss our recent results for the mass\nanomalous dimension.",
        "positive": "The negative-parity spin-1/2 $\u039b$ baryon spectrum from lattice QCD\n  and effective theory: The spectrum of the negative-parity spin-1/2 $\\Lambda$ baryons is studied\nusing lattice QCD and hadronic effective theory in a unitarized coupled-channel\nframework. A direct comparison between the two approaches is possible by\nconsidering the hadronic effective theory in a finite volume and with hadron\nmasses and mesonic decay constants that correspond to the situation studied on\nthe lattice. Comparing the energy level spectrum and $SU(3)$ flavor\ndecompositions of the individual states, it is found that the lowest two states\nextracted from lattice QCD can be identified with one of the two\n$\\Lambda(1405)$-poles and the $\\Lambda(1670)$ resonance. The quark mass\ndependences of these two lattice QCD levels are in good agreement with their\neffective theory counterparts. However, as current lattice QCD studies still\nrely on three-quark operators to generate the physical states, clear signals\ncorresponding to the meson-baryon scattering states, that appear in the finite\nvolume effective theory calculation, are not yet seen."
    },
    {
        "anchor": "Eguchi-Kawai reduction with one flavor of adjoint Moebius fermion: We study the single site lattice gauge theory of SU(N) coupled to one Dirac\nflavor of fermion in the adjoint representation. We utilize M\\\"obius fermions\nfor this study, and accelerate the calculation with graphics processing units\n(GPUs). Our Monte Carlo simulations indicate that for sufficiently large\ninverse 't Hooft coupling b = 1/g^2 N, and for N \\leq 10 the distribution of\ntraced Polyakov loops has \"fingers\" that extend from the origin. However, in\nthe massless case the distribution of eigenvalues of the untraced Polyakov loop\nbecomes uniform at large N, indicating preservation of center symmetry in the\nthermodynamic limit. By contrast, for a large mass and large b, the\ndistribution is highly nonuniform in the same limit, indicating spontaneous\ncenter symmetry breaking. These conclusions are confirmed by comparing to the\nquenched case, as well as by examining another observable based on the average\nvalue of the modulus of the traced Polyakov loop. The result of this\ninvestigation is that with massless adjoint fermions center symmetry is\nstabilized and the Eguchi-Kawai reduction should be successful; this is in\nagreement with most other studies.",
        "positive": "Scaling analysis of the magnetic monopole mass and condensate in the\n  pure U(1) lattice gauge theory: We observe the power law scaling behavior of the monopole mass and condensate\nin the pure compact U(1) gauge theory with the Villain action. In the Coulomb\nphase the monopole mass scales with the exponent \\nu_m=0.49(4). In the\nconfinement phase the behavior of the monopole condensate is described with\nremarkable accuracy by the exponent \\beta_{exp}=0.197(3). Possible implications\nof these phenomena for a construction of a strongly coupled continuum U(1)\ngauge theory are discussed."
    },
    {
        "anchor": "Nonperturbative infrared finiteness in super-renormalisable scalar\n  quantum field theory: We present a study of the IR behaviour of a three-dimensional\nsuper-renormalisable quantum field theory (QFT) consisting of a scalar field in\nthe adjoint of $SU(N)$ with a $\\varphi^4$ interaction. A bare mass is required\nfor the theory to be massless at the quantum level. In perturbation theory the\ncritical mass is ambiguous due to infrared (IR) divergences and we indeed find\nthat at two-loops in lattice perturbation theory the critical mass diverges\nlogarithmically. It was conjectured long ago in [Jackiw 1980, Appelquist 1981]\nthat super-renormalisable theories are nonperturbatively IR finite, with the\ncoupling constant playing the role of an IR regulator. Using a combination of\nMarkov-Chain-Monte-Carlo simulations of the lattice-regularised theory, both\nfrequentist and Bayesian data analysis, and considerations of a corresponding\neffective theory we gather evidence that this is indeed the case.",
        "positive": "Ehrenfest theorems and charge antiscreening in Abelian projected gauge\n  theories: We derive exact relations for SU(2) lattice gauge theory in 3+1 dimensions.\nIn terms of Abelian projection, these are the expectation values of Maxwell\nequations that define a new field strength operator and conserved, dynamic\nelectric currents formed from the charged matter and ghost fields. The effect\nof gauge fixing is calculated, and in the maximally Abelian gauge we find\nantiscreening of U(1) Wilson loop source charges. We discuss the importance of\nthese quantities in the dual superconducting vacuum mechanism of confinement."
    },
    {
        "anchor": "Quenched lattice calculation of semileptonic heavy-light meson form\n  factors: We calculate, in the continuum limit of quenched lattice QCD, the matrix\nelements of the heavy-heavy vector current between heavy-light pseudoscalar\nmeson states. We present the form factors for different values of the initial\nand final meson masses at finite momentum transfer. In particular, we calculate\nthe non-perturbative correction to the differential decay rate of the process B\n--> D l nu including the case of a non-vanishing lepton mass.",
        "positive": "Baryon Masses from Lattice QCD: Beyond the Perturbative Chiral Regime: Consideration of the analytic properties of pion-induced baryon self-energies\nleads to new functional forms for the extrapolation of light baryon masses.\nThese functional forms reproduce the leading non-analytic behavior of chiral\nperturbation theory, the correct non-analytic behavior at the $N \\pi$ threshold\nand the appropriate heavy-quark limit. They involve only three unknown\nparameters, which may be obtained by fitting to lattice data. Recent dynamical\nfermion results from CP-PACS and UKQCD are extrapolated using these new\nfunctional forms. We also use these functions to probe the limit of\napplicability of chiral perturbation theory to the extrapolation of lattice QCD\nresults."
    },
    {
        "anchor": "Effective string description of the confining flux tube at finite\n  temperature: In this review, after a general introduction to the effective string theory\n(EST) description of confinement in pure gauge theories, we discuss the\nbehaviour of EST as the temperature is increased. We show that, as the\ndeconfinement point is approached from below, several universal features of\nconfining gauge theories, like the ratio $T_c/\\sqrt{\\sigma_0}$, the linear\nincrease of the squared width of the flux tube with the interquark distance, or\nthe Temperature dependence of the interquark potential, can be accurately\npredicted by the effective string. Moreover in the vicinity of the\ndeconfinement point the EST behaviour turns out to be in good agreement with\nwhat predicted by conformal invariance or by dimensional reduction, thus\nfurther supporting the validity of and EST approach to confinement.",
        "positive": "Generalized Hybrid Monte-Carlo: We propose a modification of the Hybrid Monte-Carlo method to sample\nequilibrium distributions of continuous field models. The method allows an\nefficient implementation of Fourier acceleration and is shown to reduce\ncompletely critical slowing down for the Gaussian model, i. e., $z=0$."
    },
    {
        "anchor": "Composite bosonic baryon dark matter on the lattice: SU(4) baryon\n  spectrum and the effective Higgs interaction: We present the spectrum of baryons in a new SU(4) gauge theory with\nfundamental fermion constituents. The spectrum of these bosonic baryons is of\nsignificant interest for composite dark matter theories. Here, we compare the\nspectrum and properties of SU(3) and SU(4) baryons, and then compute the\ndark-matter direct detection cross section via Higgs boson exchange for\nTeV-scale composite dark matter arising from a confining SU(4) gauge sector.\nComparison with the latest LUX results leads to tight bounds on the fraction of\nthe constituent-fermion mass that may arise from electroweak symmetry breaking.\nLattice calculations of the dark matter mass spectrum and the Higgs-dark matter\ncoupling are performed on quenched $16^{3} \\times 32$, $32^{3} \\times 64$,\n$48^{3} \\times 96$, and $64^{3} \\times128$ lattices with three different\nlattice spacings, using Wilson fermions with moderate to heavy pseudoscalar\nmeson masses. Our results lay a foundation for future analytic and numerical\nstudy of composite baryonic dark matter.",
        "positive": "'t Hooft loops and consistent order parameters for confinement: We study ratios of partition functions in two types of sectors of SU(2), with\nfixed temporal center flux and with static fundamental charge. Both can be used\nas bona fide order parameters for the deconfinement transition."
    },
    {
        "anchor": "Monopoles and hadron spectrum in quenched QCD: We study quenched hadron spectra with Wilson fermion in abelian gauge fields\nextracted by maximal abelian projection and in fields induced by monopoles on\n$16^3 \\times 32 $ and $ 12^3 \\times 24$ lattices. Pion mass squared and quark\nmass defined through the axial Ward identity satisfy the PCAC relation. Gross\nfeatures of the light hadron spectra are almost similar to those in SU(3) gauge\nfields if normalization is made by the square root of the string tension. It is\nalso shown that no sizable dynamical mass generation is found in the present\nrange of $\\kappa$ when the monopole degree of freedom is removed from the\nabelian fields or from the SU(3) gauge fields.",
        "positive": "Abelian chromomagnetic background field at finite temperature on the\n  lattice: The vacuum dynamics of SU(2) and SU(3) lattice gauge theories is studied by\nmeans of a gauge-invariant effective action defined using the lattice\nSchr\\\"odinger functional at finite temperature. In the case of the SU(3) gauge\ntheory numerical simulations are performed both at zero and finite temperature.\nThe vacuum is probed using an external constant Abelian chromomagnetic field.\nAt zero temperature, in agreement with our previous studies for the SU(2)\ntheory, the external field is totally screened in the continuum limit. At\nfinite temperature numerical data suggest that confinement is restored by\nincreasing the strength of the applied field."
    },
    {
        "anchor": "Lattice field theory with torsion: Inspired by the duality between gravity and defects in crystals, we study\nlattice field theory with torsion. The torsion is realized by a line defect of\na lattice, namely a dislocation. As the first application, we perform the\nnumerical computation for vector and axial currents induced by a screw\ndislocation. This current generation is called the chiral torsional effect. We\nalso derive the analytical formula for the chiral torsional effect in the\ncontinuum limit.",
        "positive": "Dimensional reduction and the phase diagram of 5d Yang-Mills theory: We present a non-perturbative study of the phase diagram of 5d SU(2)\nYang-Mills theory with one compact extra dimension on the lattice. Assuming at\nleast a modest scale separation between the cutoff and the compactification\nscales leads to an exponential separation between the compactification scale\nand the four-dimensional correlation length. While we demonstrate that it is\nnot possible to take a full five-dimensional continuum limit, this dynamical\ngeneration of scale hierarchy opens up the possibility for us to make limited,\nbut non-perturbative, predictions about continuum theories whose low-energy\nsector is described by an effective 5d Yang-Mills theory."
    },
    {
        "anchor": "Analytical calculation of critical temperatures in some spin systems: A new method for locating analytically critical temperatures is discussed. It\nis exact for selfdual systems. When applied the two coupled layers of Ising\nspins it deviates from our preliminary Monte Carlo estimates by 1.5 standard\ndeviations. It predicts critical temperature of the three dimensional Ising\nmodel in terms of the solution of the two layer Ising system.",
        "positive": "Neural Network Field Transformation and Its Application in HMC: We propose a generic construction of Lie group agnostic and gauge covariant\nneural networks, and introduce constraints to make the neural networks\ncontinuous differentiable and invertible. We combine such neural networks and\nbuild gauge field transformations that is suitable for Hybrid Monte Carlo\n(HMC). We use HMC to sample lattice gauge configurations in the transformed\nspace by the neural network parameterized gauge field transformations. Tested\nwith 2D U(1) pure gauge systems at a range of couplings and lattice sizes,\ncompared with direct HMC sampling, the neural network transformed HMC (NTHMC)\ngenerates Markov chains of gauge configurations with improved tunneling of\ntopological charges, while allowing less force calculations as the lattice\ncoupling increases."
    },
    {
        "anchor": "Hyperscaling in the Broken Symmetry Phase of Dyson's Hierarchical Model: We use polynomial truncations of the Fourier transform of the local measure\nto calculate the connected q-point functions of Dyson's hierarchical model in\nthe broken symmetry phase. We show that accurate values of the connected 1, 2\nand 3 point functions can be obtained at large volume and in a limited range of\nconstant external field coupled linearly to the field variable. We introduce a\nnew method to obtain the correct infinite volume and zero external field\nextrapolations. We extract the leading critical exponents and show that they\nobey the scaling and hyperscaling relations with an accuracy ranging from 10^-5\nto 5 10^-3. We briefly discuss how to improve the method of calculation.",
        "positive": "Fate of the Critical Line and Chiral Transition in Finite-Temperature\n  Lattice QCD with the Wilson Quark Action: Finite-temperature phase structure of lattice QCD with the Wilson quark\naction is analyzed. We show that the critical line at finite temperatures,\ndefined to be the line of vanishing pion screening mass, turns back toward\nstrong coupling, forming a cusp on the $(\\beta, K)$ plane, and that the line of\nthermal transition runs past the tip of the cusp without touching the critical\nline. Previous results are discussed in the light of our findings."
    },
    {
        "anchor": "Aspects of lattice N=4 supersymmetric Yang--Mills: Non-perturbative investigations of $\\mathcal N = 4$ supersymmetric\nYang--Mills theory formulated on a space-time lattice have advanced rapidly in\nrecent years. Large-scale numerical calculations are currently being carried\nout based on a construction that exactly preserves a single supersymmetry at\nnon-zero lattice spacing. A recent development is the creation of an improved\nlattice action through a new procedure to regulate flat directions in a manner\ncompatible with this supersymmetry, by modifying the moduli equations. In this\nproceedings I briefly summarize this new procedure and discuss the parameter\nspace of the resulting improved action that is now being employed in numerical\ncalculations.",
        "positive": "Two-flavor QCD simulation with exact chiral symmetry: We perform numerical simulations of lattice QCD with two flavors of dynamical\noverlap quarks, which have exact chiral symmetry on the lattice. While this\nfermion discretization is computationally demanding, we demonstrate the\nfeasibility to simulate reasonably large and fine lattices by a careful choice\nof the lattice action and algorithmic improvements. Our production runs are\ncarried out on a 16^3 \\times 32 lattice at a single lattice spacing around 0.12\nfm. We explore the sea quark mass region down to m_s/6, where m_s is the\nphysical strange quark mass, for a good control of the chiral extrapolation in\nfuture calculations of physical observables. We describe in detail our setup\nand algorithmic properties of the production simulations and present results\nfor the static quark potential to fix the lattice scale and the locality of the\noverlap operator."
    },
    {
        "anchor": "Super-Instantons and the Reliability of Perturbation Theory in\n  Non-Abelian Models: In dimension $D\\leq 2$ the low temperature behavior of systems enjoying a\ncontinuous symmetry is dominated by super-instantons: classical configurations\nof arbitrarily low energy. Perturbation theory in the background of a\nsuper-instanton produces thermodynamic answers for the invariant Green's\nfunctions that differ from the standard ones, but only in non-Abelian models\nand only starting at $O(1/\\beta^2)$. This effect modifies the $\\beta$-function\nof the $O(N)$ models and persists in the large $N$ limit of the $O(N)$ models.",
        "positive": "Renormalization functions for Nf=2 and Nf=4 Twisted Mass fermions: We present results on the renormalization functions of the quark field and\nfermion bilinears with up to one covariant derivative. For the fermion part of\nthe action we employ the twisted mass formulation with $N_f{=}2$ and $N_f{=}4$\ndegenerate dynamical quarks, while in the gluon sector we use the Iwasaki\nimproved action. The simulations for $N_f{=}4$ have been performed for pion\nmasses in the range of 390MeV - 760MeV and at three values of the lattice\nspacing, $a$, corresponding to $\\beta{=}1.90,\\,1.95,\\,2.10$. The $N_f{=}2$\naction includes a clover term with $c_{\\rm sw}{=}1.57551$ at $\\beta{=}2.10$,\nand three ensembles at different values of $m_\\pi$.\n  The evaluation of the renormalization functions is carried out in the RI$'$\nscheme using a momentum source. The non-perturbartive evaluation is\ncomplemented with a perturbative computation, which is carried out at one-loop\nlevel and to all orders in the lattice spacing, $a$. For each renormalization\nfunction computed non-perturbatively we subtract the corresponding lattice\nartifacts to all orders in $a$, so that a large part of the cut-off effects is\neliminated.\n  The renormalization functions are converted to the ${\\overline{\\rm MS}}$\nscheme at a reference energy scale of $\\mu{=}2$ GeV after taking the chiral\nlimit."
    },
    {
        "anchor": "On the first-principles determination of the Standard Model fundamental\n  parameters in the quark sector: The 2-years old observation at LHC of a new boson, with a mass of 126 GeV, is\na great achievement. Its interpretation as a Brout-Englert-Higgs boson is very\nplausible and appealing to complete the zoology of fundamental particles in the\nStandard Model. The interplay between theorists and experimentalists that we\nhave witnessed has come with a huge work to determine with enough precision the\nparameters of the Standard Model: couplings, masses, mixing angles. Among the\nvarious tools developed by physicists, lattice QCD is particularly suitable to\nknow those parameters in the quark sector. In this report I discuss the lattice\nmeasurement of Standard Model fundamental parameters that are closely related\nto Higgs boson: its main production mode is the gluon-gluon fusion, whose the\nmagnitude is governed by the strong coupling constant, while its most favored\ndecay channel, $H \\to b \\bar{b}$, has a coupling proportional to the $b$ quark\nmass. I outline the improvements brought by the lattice community: simulations\nwith $N_f=2+1+1$ dynamical quarks are crucial to study how much the charm quark\nimpacts the strong coupling constant calculation. A non perturbative matching\nbetween Heavy Quark Effective Theory and QCD is welcome to handle in an\nappropriate way the $b$ quark physics. An extensive methodological exploration\nis necessary to get rid of contribution from excited states in correlation\nfunctions computed to extract hadron masses and decay constants. The effort to\nmeasure the $u/d$, $s$ and $c$ quark masses is also discussed, illustrating the\nbenefit of using an automatic $O(a)$ improved lattice regularization.",
        "positive": "Continuum versus periodic lattice Monte Carlo approach to classical\n  field theory: We compare the momentum space with the standard periodic lattice approach to\nMonte Carlo calculations in classical $\\phi^4$ field theory. We show that the\nmismatch in the initial value of $\\phi^2_{\\text{cl}}(t)$, results in a shift in\nthe ``thermalized'' value, at large times. The two approaches converge to the\nsame result in the continuum limit."
    },
    {
        "anchor": "Phase diagram of adjoint QCD at weak coupling and finite volume: The phase diagram of SU(N) gauge theories with fermions in an arbitrary\nrepresentation R can be calculated on finite volume manifolds such as S^1 x\nS^3. When S^3 is small a perturbative analysis is possible and the\nweak-coupling analogue of the pure Yang-Mills theory confinement-deconfinement\ntransition is accessible in the large N limit. We calculate the large N phase\ndiagram of adjoint QCD [SU(N) gauge theory with adjoint fermions] where\nperiodic boundary conditions are applied to fermions on S^1 such that the\nconfined phase is favored for light enough adjoint fermion mass. We calculate\nthe value of the mass times the radius of S^3 below which the confined phase is\nfavored for all volumes of S^1 / S^3 and discuss the implications for large N\nvolume reduction. We calculate also the phase diagram for N = 3 and compare\nwith recent lattice results.",
        "positive": "The ice-limit of Coulomb gauge Yang-Mills theory: In this paper we describe gauge invariant multi-quark states generalising the\npath integral framework developed by Parrinello, Jona-Lasinio and Zwanziger to\namend the Faddeev-Popov approach. This allows us to produce states such that,\nin a limit which we call the ice-limit, fermions are dressed with glue\nexclusively from the fundamental modular region associated with Coulomb gauge.\nThe limit can be taken analytically without difficulties, avoiding the Gribov\nproblem. This is llustrated by an unambiguous construction of gauge invariant\nmesonic states for which we simulate the static quark--antiquark potential."
    },
    {
        "anchor": "Lattice Improvement in Lattice Effective Field Theory: Lattice calculations using the framework of effective field theory have been\napplied to a wide range few-body and many-body systems. One of the challenges\nof these calculations is to remove systematic errors arising from the nonzero\nlattice spacing. Fortunately, the lattice improvement program pioneered by\nSymanzik provides a formalism for doing this. While lattice improvement has\nalready been utilized in lattice effective field theory calculations, the\neffectiveness of the improvement program has not been systematically\nbenchmarked. In this work we use lattice improvement to remove lattice errors\nfor a one-dimensional system of bosons with zero-range interactions. We\nconstruct the improved lattice action up to next-to-next-to-leading order and\nverify that the remaining errors scale as the fourth power of the lattice\nspacing for observables involving as many as five particles. Our results\nprovide a guide for increasing the accuracy of future calculations in lattice\neffective field theory with improved lattice actions.",
        "positive": "Scale Setting for CLS 2+1 Simulations: We present an update of the scale setting for $N_f=2+1$ flavor QCD using\ngradient flow scales and pseudo-scalar decay constants. We analyze the latest\nensembles with $2+1$ flavors of non-perturbatively improved Wilson fermions\ngenerated by CLS for improved precision. Special care is taken to correct for\nmistuning by measuring directly the mass derivatives of the various\nobservables. We determine $t_0$ with input taken from a combination of leptonic\ndecay rates of the Pion and the Kaon."
    },
    {
        "anchor": "Relativistic $N$-particle energy shift in finite volume: We present a general method for deriving the energy shift of an interacting\nsystem of $N$ spinless particles in a finite volume. To this end, we use the\nnonrelativistic effective field theory (NREFT), and match the pertinent\nlow-energy constants to the scattering amplitudes. Relativistic corrections are\nexplicitly included up to a given order in the $1/L$ expansion. We apply this\nmethod to obtain the ground state of $N$ particles, and the first excited state\nof two and three particles to order $L^{-6}$ in terms of the threshold\nparameters of the two- and three-particle relativistic scattering amplitudes.\nWe use these expressions to analyze the $N$-particle ground state energy shift\nin the complex $\\varphi^4$ theory.",
        "positive": "First Lattice QCD determination of semileptonic decays of\n  charmed-strange baryons $\u039e_c$: While the standard model is the most successfully theory to describe all\ninteractions and constituents in elementary particle physics, it has been\nconstantly examined for over four decades. Weak decays of charm quarks can\nmeasure the coupling strength of quarks in different families and serve as an\nideal probe for CP violation. As the lowest charm-strange baryons with three\ndifferent flavors, $\\Xi_c$ baryons (made of $csu$ or $csd$) have been\nextensively studied in experiments at the large hadron collider and in\nelectron-positron collision. However the lack of reliable knowledge in theory\nbecomes the unavoidable obstacle in the way. In this work, we use the\nstate-of-the-art Lattice QCD techniques, and generate 2+1 clover fermion\nensembles with two lattice spacings, $a=(0.108{\\rm fm},0.080{\\rm fm})$. We then\npresent the first {\\it ab-initio} lattice QCD determination of form factors\ngoverning $\\Xi_{c}\\to \\Xi \\ell^+\\nu_{\\ell}$, analogous with the notable\n$\\beta$-decay of nuclei. Our theoretical results for decay widths are\nconsistent with and about two times more precise than the latest measurements\nby ALICE and Belle collaborations. Together with experimental measurements, we\nindependently determine the quark-mixing matrix element $|V_{cs}|$, which is\nfound in good agreement with other determinations."
    },
    {
        "anchor": "Fermion Condensates in Two Colours Finite Density QCD at Strong Coupling: We study unquenched lattice SU(2) at nonzero chemical potential at strong\ncoupling and with eight flavours of Kogut-Susskind fermions. Introducing a\ndiquark source term we analyze the behaviour of different types of fermion\ncondensates. Using a non standard approach we can obtain results at zero\nexternal source without extrapolations. We find strong evidences for a (high\ndensity) second order phase transition where a diquark condensate appears. The\ncorresponding critical chemical potential is in good agreement with half the\npion mass.",
        "positive": "A precise determination of the psibar-psi anomalous dimension in\n  conformal gauge theories: A strategy for computing the psibar-psi anomalous dimension at the fixed\npoint in infrared-conformal gauge theories from lattice simulations is\ndiscussed. The method is based on the scaling of the spectral density of the\nDirac operator or rather its integral, the mode number. It is relatively cheap,\nmainly for two reasons: (a) the mode number can be determined with quite high\naccuracy, (b) the psibar-psi anomalous dimension is extracted from a fit of\nseveral observables on the same set of configurations (no scaling in the\nLagrangian parameters is needed). As an example the psibar-psi anomalous\ndimension has been computed in the SU(2) theory with 2 Dirac fermions in the\nadjoint representation of the gauge group, and has been found to be 0.371(20).\nIn this particular case, the proposed strategy has proved to be very robust and\neffective."
    },
    {
        "anchor": "Lattice QCD studies of the $\u0394$ baryon resonance and the\n  $K_0^\\ast(700)$ and $a_0(980)$ meson resonances: the role of exotic operators\n  in determining the finite-volume spectrum: Studies of the $\\Delta$ baryon resonance and the $K_0^\\ast(700)$ and\n$a_0(980)$ meson resonances using $N_f=2+1$ lattice QCD for pion masses near\n200 MeV are presented. The $s$-wave scattering lengths for both the $I=1/2$ $N\n\\pi$ and $I=3/2$ $N \\pi$ channels and properties of the $\\Delta$ resonance are\nidentified from the finite-volume energy levels of the lattice simulation. The\nimportance of a three-quark $\\Delta$-operator in the $N\\pi$ system and\ntetraquark operators in the mesonic systems is investigated.",
        "positive": "Fluctuations and Correlations of net baryon number, electric charge, and\n  strangeness: A comparison of lattice QCD results with the hadron resonance\n  gas model: We calculate the quadratic fluctuations of net baryon number, electric charge\nand strangeness as well as correlations among these conserved charges in\n(2+1)-flavor lattice QCD at zero chemical potential. Results are obtained using\ncalculations with tree level improved gauge and the highly improved staggered\nquark (HISQ) actions with almost physical light and strange quark masses at\nthree different values of the lattice cut-off. Our choice of parameters\ncorresponds to a value of 160 MeV for the lightest pseudo scalar Goldstone mass\nand a physical value of the kaon mass. The three diagonal charge\nsusceptibilities and the correlations among conserved charges have been\nextrapolated to the continuum limit in the temperature interval 150 MeV <T <\n250 MeV. We compare our results with the hadron resonance gas (HRG) model\ncalculations and find agreement with HRG model results only for temperatures\nT<= 150 MeV. We observe significant deviations in the temperature range 160 MeV\n< T < 170 MeV and qualitative differences in the behavior of the three\nconserved charge sectors. At T < 160 MeV quadratic net baryon number\nfluctuations in QCD agree with HRG model calculations while, the net electric\ncharge fluctuations in QCD are about 10% smaller and net strangeness\nfluctuations are about 20% larger. These findings are relevant to the\ndiscussion of freeze-out conditions in relativistic heavy ion collisions."
    },
    {
        "anchor": "Shaken, but not stirred - Potts model coupled to quantum gravity: We investigate the critical behaviour of both matter and geometry of the\nthree-state Potts model coupled to two-dimensional Lorentzian quantum gravity\nin the framework of causal dynamical triangulations. Contrary to what general\narguments of the effects of disorder suggest, we find strong numerical evidence\nthat the critical exponents of the matter are not changed under the influence\nof quantum fluctuations in the geometry, compared to their values on fixed,\nregular lattices. This lends further support to previous findings that quantum\ngravity models based on causal dynamical triangulations are in many ways better\nbehaved than their Euclidean counterparts.",
        "positive": "High Temperature Confinement in SU(N) Gauge Theories: SU(N) gauge theories, extended with adjoint fermions having periodic boundary\nconditions, are confining at high temperature for sufficiently light fermion\nmass m. Lattice simulations indicate that this confining region is smoothly\nconnected to the confining region of low-temperature pure SU(N) gauge theory.\nIn the high temperature confining region, the one-loop effective potential for\nPolyakov loops has a Z(N)-symmetric confining minimum. String tensions\nassociated with Polyakov loops are smooth functions of m/T. In the magnetic\nsector, the Polyakov loop plays a role similar to a Higgs field, leading to a\nbreaking of SU(N) to U(1)^{N-1}. This is turn yields an effective theory where\nmagnetic monopoles give rise to string tensions for spatial Wilson loops. These\nstring tensions are calculable semiclassically. There are many analytical\npredictions for the high-temperature region that can be tested by lattice\nsimulations, but lattice work will be crucial for exploring the crossover from\nthis region to the low-temperature confining behavior of pure gauge theories."
    },
    {
        "anchor": "Scaling dimension of $4\u03c0$-flux monopole operator in four-flavor\n  three-dimensional QED using lattice simulation: We numerically address the issue of which monopole operators are relevant\nunder renormalization group flow in three-dimensional parity-invariant\nnoncompact QED with $4$ flavors of massless two-component Dirac fermion. Using\nlattice simulation and finite-size scaling analysis of the free energy to\nintroduce monopole-antimonopole pairs in $N=4$ and $N=12$ flavor noncompact\nQED$_3$, we estimate the infrared scaling dimensions of monopole operators that\nintroduce $2\\pi$ and $4\\pi$ fluxes around them. We first show that the\nestimates for the monopole scaling dimensions are consistent with the large-$N$\nexpectations for $N=12$ QED$_3$. Applying the same procedure in $N=4$ QED$_3$,\nwe estimate the scaling dimension of $4\\pi$ flux monopole operator to be\n$3.7(3)$, which allows the possibility of the operator being irrelevant. This\nfinding offers support to the scenario in which higher-flux monopoles are\nirrelevant deformations to the Dirac spin liquid phase that could be realized\non certain non-bipartite lattices by forbidding $2\\pi$-flux monopoles.",
        "positive": "The pion form factor on the lattice at zero and finite temperature: We calculate the electromagnetic form factor of the pion in quenched lattice\nQCD. The non-perturbatively improved Sheikoleslami-Wohlert lattice action is\nused together with the consistently O(a) improved current. We calculate the\npion form factor for masses down to m_pi = 360 MeV, extract the charge radius,\nand extrapolate toward the physical pion mass. In the second part, we discuss\nresults for the pion form factor and charge radius at 0.93 T_c and compare with\nzero temperature results."
    },
    {
        "anchor": "Tensor renormalization of three-dimensional Potts model: We study the $q$-state Potts models on a cubic lattice in the thermodynamic\nlimit using tensor renormalization group transformations with the triad\napproximation. By computing the thermodynamic potentials, we locate the\nfirst-order phase transitions for $10 < q \\le 20$ which has not been explored\nusing any method. We also examine the efficiency of the triad approximation\nmethod in obtaining the fixed-point tensor and comment on how this can be\nimproved.",
        "positive": "Finite-volume effects and meson scattering in the 2-flavour Schwinger\n  model: We investigate the 2-flavour Schwinger model in the canonical formulation\nwith fixed fermion numbers. We use Wilson fermions and a formalism which\ndescribes the determinant of the Dirac operator in terms of dimensionally\nreduced canonical transfer matrices. These transfer matrices allow the direct\nexamination of arbitrary multi-particle (meson) sectors and the determination\nof the corresponding ground-state energies. We discuss the finite-volume\neffects in the meson mass. From the 2-meson energies, we determine the\nscattering phase shifts and compare the 3-meson energies at finite volume to\npredictions based on 3-particle quantization conditions."
    },
    {
        "anchor": "Toolkit for staggered $\u0394S=2$ matrix elements: A recent numerical lattice calculation of the kaon mixing matrix elements of\ngeneral $\\Delta S=2$ four-fermion operators using staggered fermions relied on\ntwo auxiliary theoretical calculations. Here we describe the methodology and\npresent the results of these two calculations. The first concerns one-loop\nmatching coefficients between staggered lattice operators and the corresponding\ncontinuum operators. Previous calculations with staggered fermions have used a\nnon-standard regularization scheme for the continuum operators, and here we\nprovide the additional matching factors needed to connect to the standard\nregularization scheme. This is the scheme in which two-loop anomalous\ndimensions are known. We also observe that all previous calculations of this\noperator matching using staggered fermions have overlooked one matching step in\nthe continuum. This extra step turns out to have no impact on three of the five\noperators (including that relevant for $B_K$), but does affect the other two\noperators. The second auxiliary calculation concerns the two-loop\nrenormalization group (RG) evolution equations for the $B$-parameters of the\n$\\Delta S=2$ operators. For one pair of operators, the standard analytic\nsolution to the two-loop RG equations fails due to a spurious singularity\nintroduced by the approximations made in the calculation. We give a\nnon-singular expression derived using analytic continuation, and check the\nresult using a numerical solution to the RG equations. We also describe the RG\nevolution for \"golden\" combinations of $B$-parameters, and give numerical\nresults for RG evolution matrices needed in the companion lattice calculation.",
        "positive": "Confinement and string breaking for QED$_2$ in the Hamiltonian picture: The formalism of matrix product states is used to perform a numerical study\nof 1+1 dimensional QED -- also known as the (massive) Schwinger model -- in the\npresence of an external static `quark' and `antiquark'. We obtain a detailed\npicture of the transition from the confining state at short interquark\ndistances to the broken-string `hadronized' state at large distances and this\nfor a wide range of couplings, recovering the predicted behavior both in the\nweak and strong coupling limit of the continuum theory. In addition to the\nrelevant local observables like charge and electric field, we compute the\n(bipartite) entanglement entropy and show that subtraction of its vacuum value\nresults in a UV-finite quantity. We find that both string formation and string\nbreaking leave a clear imprint on the resulting entropy profile. Finally, we\nalso study the case of fractional probe charges, simulating for the first time\nthe phenomenon of partial string breaking."
    },
    {
        "anchor": "Some Interesting Features of Noncompact QED_3: We study the phase diagram of non compact $QED_3$ using the $MFA$ method and\npresent evidence for a continuous phase transition line at small $N_f$. We also\nanalyze the chiral structure of the vacuum by means of the computation of the\nprobability distribution function of the order parameter in the exact chiral\nlimit.",
        "positive": "Finite volume effects for meson masses and decay constants: We present a detailed numerical study of finite volume effects for masses and\ndecay constants of the octet of pseudoscalar mesons. For this analysis we use\nchiral perturbation theory and asymptotic formulae a la Luscher and propose an\nextension of the latter beyond the leading exponential term. We argue that such\na formula, which is exact at the one-loop level, gives the numerically dominant\npart at two loops and beyond. Finally, we discuss the possibility to determine\nlow energy constants from the finite volume dependence of masses and decay\nconstants."
    },
    {
        "anchor": "Propagators in lattice Coulomb gauge and confinement mechanisms: We discuss the gluon propagator in 3- and 4-dimensional Yang-Mills theories\nin Coulomb gauge and compare it with the corresponding Landau gauge propagator,\nshowing that for both the relevant IR mass scale coincides. We also report\npreliminary results on Coulomb gauge ghost form factor and quark propagators\nand give a comment on the gluon propagator's strong coupling limit.",
        "positive": "Dynamical role of Polyakov loops in the QCD thermodynamics: Polyakov loops $L_a(T), a=3,8,...$ are shown to give the most important\nnonperturbative contribution to the thermodynamic potentials. Derived from the\ngluonic field correlators they enter as factors into free energy. It is shown\nin the $SU(3)$ case that $L_a (T)$ define to a large extent the behavior of the\nfree energy and the trace anomaly $I(T)$, most sensitive to nonperturbative\neffects."
    },
    {
        "anchor": "Renormalization of the \u0394B=2 four-quark operators in lattice NRQCD: We calculate perturbative renormalization constants for the \\Delta B=2\nfour-quark operators in lattice NRQCD.\n  Continuum operators \\bar{b}\\gamma_{\\mu}(1-\\gamma_5)q~\n  \\bar{b}\\gamma_{\\mu}(1-\\gamma_5)q and\n\\bar{b}(1-\\gamma_5)q~\\bar{b}(1-\\gamma_5)q, which are necessary in evaluating\nthe mass and width differences in $B^0_{d(s)}-\\bar{B}^0_{d(s)}$ systems, are\nmatched at one-loop with corresponding lattice operators constructed from the\nNRQCD heavy quarks and the ${\\cal O}(a)$-improved light quarks. Using these\nperturbative coefficients, we also reanalyse our previous simulation results\nfor the matrix elements of the above operators. Our new results are free from\nthe systematic error of ${\\cal O}(\\alpha_s/(aM_b))$ in contrast to the previous\nones with matching coefficients evaluated in the static limit.",
        "positive": "High precision applications of lattice gauge theories in the quest for\n  new physics: We present some aspects of high precision calculations in the context of\nLattice Quantum Field Theory. This work is a collection of three studies done\nduring my Ph.D. period. First we present how to use the reweighting technique\nto compensate for the breaking of unitarity due to the use of different\nboundary conditions in the valence and sea sector. In particular when twisted\nboundary conditions are employed, with $\\theta$ twisting angle. In large volume\nwe found that the breaking is negligible, while in rather small volumes an\neffect is present. The quark mass appears to change with $\\theta$ as a cutoff\neffect. In the second part of the dissertation we present an optimization\nmethod for Hybrid Monte Carlo performances. The work is based on the existence\nof a shadow Hamiltonian, an exactly conserved quantity along the Molecular\nDynamics trajectory. The optimization method is economic since it only requires\nthe forces to be measured, which are already used for the evolution from one\nconfiguration to the new one. We found predictions for the cost of the\nsimulations with an accuracy of 10% and we could estimate the optimal\nparameters for the Omelyan integrator with mass-preconditioning and multi\ntime-scale. In the last part of the work we address the calculation of\nelectromagnetic corrections to the hadronic contribution to the $(g-2)$ anomaly\nof the muon. A long standing discrepancy between theoretical calculations and\nexperimental results is present. But before invoking New Physics we need to\nclear the sight from possible effects within the Standard Model. In this\nexploratory study we carefully matched the masses of the charged pions in the\ntheory with and without QED. We found a visible effect at the percent level\nalthough consistent with zero within two sigmas."
    },
    {
        "anchor": "The static energy of a quark-antiquark pair from Laplacian eigenmodes: We test a method for computing the static quark-antiquark potential in\nlattice QCD, which is not based on Wilson loops, but where the trial states are\nformed by eigenvector components of the covariant lattice Laplace operator. The\nruntime of this method is significantly smaller than the standard Wilson loop\ncalculation, when computing the static potential not only for on-axis, but also\nfor many off-axis quark-antiquark separations, i.e., when a fine spatial\nresolution is required. We further improve the signal by using multiple\neigenvector pairs, weighted with Gaussian profile functions of the eigenvalues,\nproviding a basis for a generalized eigenvalue problem (GEVP), as it was\nrecently introduced to improve distillation in meson spectroscopy. We show\nresults with the new method for the static potential with dynamical fermions\nand demonstrate its efficiency compared to traditional Wilson loop\ncalculations. The method presented here can also be applied to compute hybrid\nor tetra-quark potentials and to static-light systems.",
        "positive": "Scale setting via the \u03a9 baryon mass: We present the first results of an ongoing effort to determine the lattice\nscale on the N_f=2 CLS lattice ensembles via the mass of the \\Omega\\ baryon.\nResults from different methods are compared, and various sources of systematic\nuncertainty are discussed."
    },
    {
        "anchor": "The theoretical background and properties of perfect actions: This lecture note starts with a pedagogical introduction to the theoretical\nbackground and properties of perfect actions, gives some details on topology\nand instanton solutions and ends with a discussion on the recent developments\nconcerning chiral symmetry.",
        "positive": "Evaluating topological charge density with symmetric multi-probing\n  method: We evaluated the topological charge density of SU(3) gauge fields on lattice\nby calculating the trace of overlap Dirac matrix employing symmetric\nmulti-probing(SMP) method with 3 modes. Since the topological charge $Q$ for a\ngiven lattice configuration must be an integer number, it's easy to estimate\nthe systematic error (the deviation of $Q$ to nearest integer). The results\nshowed high efficiency and accuracy in calculating the trace of the inverse of\na large sparse matrix with locality by using SMP sources, compared with that\nusing point sources. We also showed the correlation between the errors and\nprobing scheme parameter $r_{\\mathrm{min}}$ as well as lattice volume $N_{L}$\nand lattice spacing $a$. It was found that the computing time of calculating\nthe trace by employing SMP sources is less dependent on $N_{L}$ than that by\nusing point sources. Therefore the SMP method is very suitable for calculations\non large lattices."
    },
    {
        "anchor": "Form factor ratios for $B_s \\rightarrow K \\, \\ell \\, \u03bd$ and $B_s\n  \\rightarrow D_s \\, \\ell \\, \u03bd$ semileptonic decays and $|V_{ub}/V_{cb}|$: We present a lattice quantum chromodynamics determination of the ratio of the\nscalar and vector form factors for two semileptonic decays of the $B_s$ meson:\n$B_s \\rightarrow K \\ell \\nu$ and $B_s \\rightarrow D_s \\ell \\nu$. In conjunction\nwith future experimental data, our results for these correlated form factors\nwill provide a new method to extract $|V_{ub}/V_{cb}|$, which may elucidate the\ncurrent tension between exclusive and inclusive determinations of these\nCabibbo-Kobayashi-Maskawa mixing matrix parameters. In addition to the form\nfactor results, we determine the ratio of the differential decay rates, and\nforward-backward and polarization asymmetries, for the two decays.",
        "positive": "Continuum limit of finite temperature $\u03bb\u03c6^4_3$ from lattice\n  Monte Carlo: The $\\phi^4_3$ model at finite temperature is simulated on the lattice. For\nfixed $N_t$ we compute the transition line for $N_s \\to \\infty$ by means of\nFinite Size Scaling techniques. The crossings of a Renormalization Group\ntrajectory with the transition lines of increasing $N_t$ give a well defined\nlimit for the critical temperature in the continuum. By considering different\nRG trajectories, we compute $T^c/g$ as a function of the renormalized\nparameters."
    },
    {
        "anchor": "Three dimensional vacuum domains in four dimensional SU(2) gluodynamics: Performing lattice simulations of the four dimensional SU(2)gluodynamics we\nfind evidence for existence of three-dimensional domains whose total volume\nscales in physical units. Technically, the domains are defined in terms of the\nminimal density of negative links in Z(2) projection of gauge fields. The\nvolume can be viewed also as the minimal volume bound by the center vortices.\nWe argue that the three-dimensional domains are closely related to confinement.",
        "positive": "Weak hamiltonian Wilson Coefficients from Lattice QCD: In this work we present a calculation of the Wilson Coefficients $C_1$ and\n$C_2$ of the Effective Weak Hamiltonian to all-orders in $\\alpha_s$, using\nlattice simulations. Given the current availability of lattice spacings we\nrestrict our calculation to unphysically light $W$ bosons around 2 GeV and we\nstudy the systematic uncertainties of the two Wilson Coefficients."
    },
    {
        "anchor": "Ph.D. Thesis: Chiral Effective Field Theory Beyond the Power-Counting\n  Regime: Novel techniques are presented, which identify the power-counting regime\n(PCR) of chiral effective field theory, and allow the use of lattice quantum\nchromodynamics results that extend outside the PCR. By analyzing the\nrenormalization of low-energy coefficients of the chiral expansion of the\nnucleon mass, the existence of an optimal regularization scale is realized. The\ntechniques developed for the nucleon mass renormalization are then applied to a\ntest case: performing a chiral extrapolation without prior phenomenological\nbias. The robustness of the procedure for obtaining an optimal regularization\nscale and performing a reliable chiral extrapolation is confirmed. The\nprocedure developed is then applied to the magnetic moment and the electric\ncharge radius of the nucleon. The consistency of the results for the value of\nthe optimal regularization scale provides strong evidence for the existence of\nan intrinsic energy scale in the nucleon-pion interaction.",
        "positive": "Antiheavy-Antiheavy-Light-Light Four-Quark Bound States: We present our recent results on antiheavy-antiheavy-light-light tetraquark\nsystems using lattice QCD. Our study of the $ \\bar{b}\\bar{b}us $ four-quark\nsystem with quantum numbers $ J^P=1^+ $ and the $ \\bar{b}\\bar{c}ud $ four-quark\nsystems with $ I(J^P)=0(0^+) $ and $ I(J^P)=0(1^+) $ utilizes scattering\noperators at the sink to improve the extraction of the low-lying energy levels.\nWe found a bound state for $ \\bar{b}\\bar{b}us $ with $\nE_{\\textrm{bind},\\bar{b}\\bar{b}us} = (-86 \\pm 22 \\pm 10)\\,\\textrm{MeV} $, but\nno indication for a bound state in both $ \\bar{b}\\bar{c}ud $ channels.\nMoreover, we show preliminary results for $ \\bar{b}\\bar{b}ud $ with $\nI(J^P)=0(1^+) $, where we used scattering operators both at the sink and the\nsource. We found a bound state and determined its infinite-volume binding\nenergy with a scattering analysis, resulting in $\nE_{\\textrm{bind},\\bar{b}\\bar{b}ud} =(-103 \\pm 8 )\\,\\textrm{MeV} $."
    },
    {
        "anchor": "Mass and Axial current renormalization in the Schr\u00f6dinger functional\n  scheme for the RG-improved gauge and the stout smeared $O(a)$-improved Wilson\n  quark actions: We present the quark mass and axial current renormalization factors for the\nRG-improved Iwasaki gauge action and three flavors of the stout smeared\n$O(a)$-improved Wilson quark action. We employ $\\alpha=0.1$ and\n$n_{\\mathrm{step}}=6$ for the stout link smearing parameters and all links in\nthe quark action are replaced with the smeared links. Using the Schr\\\"{o}dinger\nfunctional scheme we evaluate the renormalization factors at $\\beta=1.82$ where\nlarge scale simulations are being carried out.",
        "positive": "Phase structure of hot dense QCD by a histogram method: We study the phase structure of QCD at high temperature and density by\nlattice QCD simulations adopting a histogram method. The quark mass dependence\nand the chemical potential dependence of the nature of phase transition are\ninvestigated focusing on the probability distribution function (histogram). The\nshape of the distribution function changes with the quark mass and chemical\npotential. Through the shape of the distribution, the critical surface which\nseparates the first order transition and crossover regions in the heavy quark\nregion is determined for the (2+1)-flavor case. Moreover, we determined the\ncritical point at finite density for two-flavor QCD with an intermediate quark\nmass, using a Gaussian approximation of the complex phase distribution of the\nquark determinant. The chemical potential dependence of the critical quark mass\nis also evaluated in the situation where two light quarks and many massive\nquarks exist. We find that the first order transition region becomes wider with\nthe chemical potential in the many-flavor QCD."
    },
    {
        "anchor": "Scaling region of the 3D Ising universality class in finite temperature\n  QCD: We introduce a universal combination of susceptibility and correlation length\nin the 3D Ising model, depending both on temperature and external magnetic\nfield. Starting from a parametric representation of the equation of state, we\nstudy its behaviour close to the critical point. The results we derive can be\nused as a sort of \"reference frame\" to chart the scaling region of the 3D Ising\nuniversality class. More specifically, we focus on instances of Ising behaviour\nin finite temperature QCD and, among these, we are particularly interested on\nthe critical ending point in the finite density, finite temperature QCD phase\ndiagram. In this context, Monte Carlo simulations are not possible and it is\nparticularly difficult to disentangle \"magnetic-like\" from \"thermal-like\"\nobservables, thus an explicit charting of the critical region could be useful\nfor a direct comparison of experimental results with QFT/Statmech predictions.",
        "positive": "Sphaleron transition rate at high temperature in the 1+1 D abelian Higgs\n  model: New results for the rate are presented using the canonical ensemble in the\nclassical approximation on a spatial lattice. We find that the rate at high\ntemperatures is proportional to $T^2$, and strongly dependent on the lattice\nspacing $a$. We conclude that a better effective action is needed for the\nclassical approximation."
    },
    {
        "anchor": "Staggered Fermion, its Symmetry and Ichimatsu-Patterned Lattice: We investigate exact symmetries of a staggered fermion in D dimensions. The\nDirac operator is reformulated by SO(2D) Clifford algebra. The chiral symmetry,\nrotational invariance and parity symmetries are clarified in any dimension.\nLocal scalar and pseudo-scalar modes are definitely determined, in which we\nfind non-standard modes. The relation to Ichimatsu-patterned lattice approach\nis discussed.",
        "positive": "Charmonium properties in deconfinement phase in anisotropic lattice QCD: J/Psi and eta_c above the QCD critical temperature T_c are studied in\nanisotropic quenched lattice QCD, considering whether the c\\bar c systems above\nT_c are spatially compact (quasi-)bound states or scattering states. We adopt\nthe standard Wilson gauge action and O(a)-improved Wilson quark action with\nrenormalized anisotropy a_s/a_t =4.0 at \\beta=6.10 on 16^3\\times (14-26)\nlattices, which correspond to the spatial lattice volume V\\equiv\nL^3\\simeq(1.55{\\rm fm})^3 and temperatures T\\simeq(1.11-2.07)T_c. We\ninvestigate the c\\bar c system above T_c from the temporal correlators with\nspatially-extended operators, where the overlap with the ground state is\nenhanced. To clarify whether compact charmonia survive in the deconfinement\nphase, we investigate spatial boundary-condition dependence of the energy of\nc\\bar c systems above T_c. In fact, for low-lying S-wave c \\bar c scattering\nstates, it is expected that there appears a significant energy difference\n\\Delta E \\equiv E{\\rm (APBC)}-E{\\rm (PBC)}\\simeq2\\sqrt{m_c^2+3\\pi^2/L^2}-2m_c\n(m_c: charm quark mass) between periodic and anti-periodic boundary conditions\non the finite-volume lattice. In contrast, for compact charmonia, there is no\nsignificant energy difference between periodic and anti-periodic boundary\nconditions. As a lattice QCD result, almost no spatial boundary-condition\ndependence is observed for the energy of the c\\bar c system in J/\\Psi and\n\\eta_c channels for T\\simeq(1.11-2.07)T_c. This fact indicates that J/\\Psi and\n\\eta_c would survive as spatially compact c\\bar c (quasi-)bound states below\n2T_c. We also investigate a $P$-wave channel at high temperature with maximally\nentropy method (MEM) and find no low-lying peak structure corresponding to\n\\chi_{c1} at 1.62T_c."
    },
    {
        "anchor": "Spectrum of the U(1) staggered Dirac operator in four dimensions: We compare the low-lying spectrum of the staggered Dirac operator in the\nconfining phase of compact U(1) gauge theory on the lattice to predictions of\nchiral random matrix theory. The small eigenvalues contribute to the chiral\ncondensate similar as for the SU(2) and SU(3) gauge groups. Agreement with the\nchiral unitary ensemble is observed below the Thouless energy, which is\nextracted from the data and found to scale with the lattice size according to\ntheoretical predictions.",
        "positive": "Real-time simulation of (2+1)-dimensional lattice gauge theory on qubits: We study the quantum simulation of Z2 lattice gauge theory in 2+1 dimensions.\nThe dual variable formulation, the so-called Wegner duality, is utilized for\nreducing redundant gauge degrees of freedom. The problem of artificial charge\nunconservation is resolved for any charge distribution. As a demonstration, we\nsimulate the real-time evolution of the system with two static electric\ncharges, i.e., with two temporal Wilson lines. Some results obtained by the\nsimulator (with no hardware noise) and the real device (with sizable hardware\nnoise) of a quantum computer are shown."
    },
    {
        "anchor": "Polyakov Loop Susceptibility and Correlators in the Chiral Limit: In quenched QCD the Polyakov loop is an order parameter of the deconfinement\ntransition, but with decreasing quark mass, the peak in the Polyakov loop\nsusceptibility becomes less pronounced, and it loses its interpretation as an\nindicator for deconfinement. For this $N_f=2+1$ HISQ study, we fix the strange\nquark mass $m_s$ at its physical value and investigate the dependence of the\nPolyakov loop on the light quark mass $m_l$ in the range $m_s/m_l=27-160$,\nfollowing $m_l$ toward the chiral limit. In particular we will look how the\ninflection point and susceptibility behave as we decrease $m_l$, to see whether\none finds any indication of a crossover, and therefore whether the Polyakov\nloop is sensitive to the chiral phase transition. Preliminary results show no\nsignal of a crossover from the real part of the Polyakov loop in the vicinity\nof the chiral crossover. Closely related is an investigation of Polyakov loop\ncorrelations and the Debye mass in this limit. Preliminary results suggest\nlittle or no dependence on $m_l$.",
        "positive": "Tunneling and the Spectrum of the Potts Model: The three-dimensional, three-state Potts model is studied as a paradigm for\nhigh temperature quantum chromodynamics. In a high statistics numerical\nsimulation using a Swendson-Wang algorithm, we study cubic lattices of\ndimension as large as $64^3$ and measure correlation functions on long lattices\nof dimension $20^2\\times 120$ and $30^2\\times 120$. These correlations are\ncontrolled by the spectrum of the transfer matrix. This spectrum is studied in\nthe vicinity of the phase transition. The analysis classifies the spectral\nlevels according to an underlying $S_3$ symmetry. Near the phase transition the\nspectrum agrees nicely with a simple four-component hamiltonian model. In the\ncontext of this model, we find that low temperature ordered-ordered interfaces\nnearly always involve a disordered phase intermediate. We present a new\nspectral method for determining the surface tension between phases."
    },
    {
        "anchor": "Towards Critical Physics in 2+1d with U(2N)-Invariant Fermions: Interacting theories of N relativistic fermion flavors in reducible spinor\nrepresentations in 2+1 spacetime dimensions are formulated on a lattice using\ndomain wall fermions (DWF), for which a U(2N) global symmetry is recovered in\nthe limit that the wall separation $L_s$ is made large. The Gross-Neveu (GN)\nmodel is studied in the large-N limit and an exponential acceleration of\nconvergence to the large-$L_s$ limit is demonstrated if the usual\nparity-invariant mass $m\\bar\\psi\\psi$ is replaced by the U(2N)-equivalent\n$im_3\\bar\\psi\\gamma_3\\psi$. The GN model and two lattice variants of the\nThirring model are simulated for N = 2 using a hybrid Monte Carlo algorithm,\nand studies made of the symmetry-breaking bilinear condensate and its\nassociated susceptibility, the axial Ward identity, and the mass spectrum of\nboth fermion and meson excitations. Comparisons are made with existing results\nobtained using staggered fermions. For the GN model a symmetry-breaking phase\ntransition is observed, the Ward identity is recovered, and the spectrum found\nto be consistent with large-N expectations. There appears to be no obstruction\nto the study of critical UV fixed-point physics using DWF. For the Thirring\nmodel the Ward identity is not recovered, the spectroscopy measurements are\ninconclusive, and no symmetry breaking is observed all the way up to the\neffective strong coupling limit. This is consistent with a critical Thirring\nflavor number $N_c<2$, contradicting earlier staggered fermion results.",
        "positive": "Monte Carlo simulations of the NJL model near the nonzero temperature\n  phase transition: We present results from numerical simulations of the Nambu-Jona-Lasinio model\nwith an SU(2)xSU(2) chiral symmetry and N_c=4,8, and 16 quark colors at nonzero\ntemperature. We performed the simulations by utilizing the hybrid Monte Carlo\nand hybrid Molecular Dynamics algorithms. We show that the model undergoes a\nsecond order phase transition. The critical exponents measured are consistent\nwith the classical 3d O(4) universality class and hence in accordance with the\ndimensional reduction scenario. We also show that the Ginzburg region is\nsuppressed by a factor of 1/N_c in accordance with previous analytical\npredictions."
    },
    {
        "anchor": "Update on the Sea Contributions to Hadron Electric Polarizabilities\n  through Reweighting: We present the results of a reweighting calculation to compute the\ncontribution of the charged quark sea to the neutron electric polarizability.\nThe chief difficulty is the stochastic estimation of weight factors, and we\npresent a hopping parameter expansion-based technique for reducing the\nstochastic noise, along with a discussion of why this particular reweighting is\nso difficult. We used this technique to estimate weight factors for 300\nconfigurations of nHYP-clover fermions and compute the neutron polarizability,\nbut the reweighting greatly inflates the overall statistical error, driven by\nthe stochastic noise in the weight factors.",
        "positive": "Chiral fermions on a finite lattice: We discuss how to formulate Dirac fermion operator on a finite lattice such\nthat it can provide a nonperturbative regularization for massless fermion\ninteracting with a background gauge field."
    },
    {
        "anchor": "Lattice Landau gauge quark propagator and the quark-gluon vertex: We report preliminary results of our ongoing lattice computation of the\nLandau gauge quark propagator and the soft gluon limit of the quark-gluon\nvertex with 2 flavors of dynamical O(a) improved Wilson fermions.",
        "positive": "On Lattice Computations of K+ --> pi+ pi0 Decay at m_K =2m_pi: We use one-loop chiral perturbation theory to compare potential lattice\ncomputations of the K+ --> pi+ pi0 decay amplitude at m_K=2m_pi with the\nexperimental value. We find that the combined one-loop effect due to this\nunphysical pion to kaon mass ratio and typical finite volume effects is still\nof order minus 20-30%, and appears to dominate the effects from quenching."
    },
    {
        "anchor": "More about QCD on compact spaces: We present some results about spontaneous breaking of global symmetries for\nfour-flavor, three color QCD on compact spaces with two short directions. When\nthe two short directions have equal length and identical boundary conditions,\nthere is a single transition. When the two short directions have boundary\nconditions of opposite parity and are of roughly equal extent, the C-breaking\nand deconfinement transitions separate. When the two short dimensions are of\ndifferent length, the transitions are modified in qualitative agreement with\nexpectations from dimensional reduction. These features resemble the situation\nin pure gauge simulations at small and large number of colors.",
        "positive": "Least-Squared Optimized Polynomials for Smeared Link Actions: We introduce a numerical method for generating the approximating polynomials\nused in fermionic calculations with smeared link actions. We investigate the\nstability of the algorithm and determine the optimal weight function and the\noptimal type of discretization. The achievable order of polynomial\napproximation reaches several thousands allowing fermionic calculations using\nthe Hypercubic Smeared Link action even with physical quark masses."
    },
    {
        "anchor": "Sign problem and MEM: The sign problem is notorious in Monte\n  Carlo simulations of lattice QCD with the finite density, lattice field\ntheory (LFT) with a $\\theta$ term and quantum spin models. In this report, to\ndeal with the sign problem, we apply the maximum entropy method (MEM) to LFT\nwith the $\\theta$ term and investigate to what extent the\n  MEM is applicable to this issue. Based on this study, we also make a brief\ncomment about lattice QCD with the finite density in terms of the\n  MEM.",
        "positive": "The perfect action for non-degenerate staggered fermions: The perfect action of free staggered fermions is calculated by blocking from\nthe continuum for degenerate and non-degenerate flavor masses. The symmetry\nstructure, connecting flavor transformations and translations, is explained\ndirectly from the blocking scheme. It is convenient to use a modified Fourier\ntransformation, respecting this connection, to treat the spin-flavor structure\nof the blockspins. The perfect action remains local in the non-degenerate case;\nit is explicitly calculated in two dimensions. I finally comment on the\nrelation of the blocking scheme to the transition from Dirac-K\\\"ahler fermions\nto staggered fermions."
    },
    {
        "anchor": "Pion structure from twisted mass lattice QCD down to the physical pion\n  mass: We present an investigation of pion structure based on ETMC $N_f=2$ and\n$N_f=2+1+1$ twisted mass configurations at maximal twist. We compute the first\nmoment of the quark momentum fraction of the pion, $\\langle x \\rangle$ and the\nelectromagnetic form factor, $F_\\pi(Q^2)$. For the latter, momentum is injected\nusing twisted boundary conditions and the calculation is carried out directly\nat the physical pion mass. We find that our data are consistent with vector\nmeson dominance and experimental data in the region of small momentum transfer.\nFor $\\langle x \\rangle$, we find that our chirally and continuum extrapolated\nresult is compatible with its phenomenological value.",
        "positive": "Deflation as a Method of Variance Reduction for Estimating the Trace of\n  a Matrix Inverse: Many fields require computing the trace of the inverse of a large, sparse\nmatrix. The typical method used for such computations is the Hutchinson method\nwhich is a Monte Carlo (MC) averaging over matrix quadratures. To improve its\nconvergence, several variance reductions techniques have been proposed. In this\npaper, we study the effects of deflating the near null singular value space. We\nmake two main contributions.\n  First, we analyze the variance of the Hutchinson method as a function of the\ndeflated singular values and vectors. Although this provides good intuition in\ngeneral, by assuming additionally that the singular vectors are random unitary\nmatrices, we arrive at concise formulas for the deflated variance that include\nonly the variance and mean of the singular values. We make the remarkable\nobservation that deflation may increase variance for Hermitian matrices but not\nfor non-Hermitian ones. This is a rare, if not unique, property where\nnon-Hermitian matrices outperform Hermitian ones. The theory can be used as a\nmodel for predicting the benefits of deflation.\n  Second, we use deflation in the context of a large scale application of\n\"disconnected diagrams\" in Lattice QCD. On lattices, Hierarchical Probing (HP)\nhas previously provided an order of magnitude of variance reduction over MC by\nremoving \"error\" from neighboring nodes of increasing distance in the lattice.\nAlthough deflation used directly on MC yields a limited improvement of 30% in\nour problem, when combined with HP they reduce variance by a factor of over 60\ncompared to MC. For this, we pre-computated 1000 smallest singular values of an\nill-conditioned matrix of size 25 million. Using PRIMME and a domain-specific\nAlgebraic Multigrid preconditioner, we perform one of the largest eigenvalue\ncomputations in Lattice QCD at a fraction of the cost of our trace computation."
    },
    {
        "anchor": "Extracting excited states from lattice QCD: the Roper resonance: We present a new method for extracting excited states from a single two-point\ncorrelation function calculated on the lattice. Our method simply combines the\ncorrelation function evaluated at different time slices so as to ``subtract''\nthe leading exponential decay (ground state) and to give access to the first\nexcited state. The method is applied to a quenched lattice study (volume = 24^3\nx 64, beta = 6.2, 1/a = 2.55 GeV) of the first excited state of the nucleon\nusing the local interpolating operator O = [uT C gamma5 d] u. The results are\nconsistent with the identification of our extracted excited state with the\nRoper resonance N'(1440). The switching of the level ordering with respect to\nthe negative-parity partner of the nucleon, N*(1535), is not seen at the\nsimulated quark masses and, basing on crude extrapolations, is tentatively\nexpected to occur close to the physical point.",
        "positive": "Heavy Quark Physics: Lattice calculations of heavy quark systems provide very good measures of the\nlattice spacing, a key element in recent determinations of the strong coupling\nconstant using lattice methods. They also provide excellent testing grounds for\nlattice methods in general. I review recent phenomenological and technical\ndevelopments in this field."
    },
    {
        "anchor": "Continuum Moment Equations on the Lattice: An analysis is given as to why one can not directly evaluate continuum moment\nequations, i.e., equations involving powers of the position variable times\ncharge, current, or energy/momentum operators, on the lattice. I examine two\ncases: a three point function evaluation of the nucleon magnetic moment and a\nfour point function (charge overlap) evaluation of the pseudoscalar charge\nradius.",
        "positive": "Localization and topology in high temperature QCD: At high temperature part of the spectrum of the quark Dirac operator is known\nto consist of localized states. This comes about because around the crossover\ntemperature to the quark-gluon plasma localized states start to appear at the\nlow end of the spectrum and as the system is further heated, states higher up\nin the spectrum also get localized. Since localization and the crossover to the\nchirally restored phase happen around the same temperature, the question of how\nthe two phenomena are connected naturally arises. Here we speculate on the\nnature of possible gauge configurations that could support localized quark\neigenmodes. In particular, by analyzing eigenmodes of the staggerd and overlap\nDirac operator we show that the dilute gas of calorons in the high temperature\nphase is very unlikely to play a major role in localization."
    },
    {
        "anchor": "Control variates for lattice field theory: In most lattice field theories, correlators are plagued by a signal-to-noise\nproblem of exponential difficulty in the time separation. We propose a method\nfor improving the signal-to-noise ratio, in which control variates are\nsystematically constructed from lattice Schwinger-Dyson relations. The method\nis demonstrated on various two-dimensional lattices in scalar field theory, and\na strategy for scaling to larger systems is explored.",
        "positive": "Hybrid stochastic method for the tensor renormalization group: We propose a hybrid stochastic method for the tensor renormalization group\n(TRG) approach. TRG is known as a powerful tool to study the many-body systems\nand quantum field theory on the lattice. It is based on a low-rank\napproximation of the tensor using the truncated singular value decomposition\n(SVD), whose computational cost increases as the bond dimension increases, so\nthat efficient cost reduction techniques are highly demanded. We use noise\nvectors for the low-rank approximation with the truncated SVD, by which the\ntruncation error is replaced with a statistical error due to noise, and an\nerror estimation could be improved. We test this method in the classical Ising\nmodel and observe a better accuracy than TRG. We also discuss a cross\ncontamination issue in a multiple use of the same noise vectors, and to remove\nthis systematic error we consider position-dependent noise vectors."
    },
    {
        "anchor": "Taming the pion condensation in QCD at finite baryon density: In the Monte Carlo study of QCD at finite baryon density based upon the phase\nreweighting method, the pion condensation in the phase-quenched theory and\nassociated zero-mode prevent us to go to the low-temperature high-density\nregion. We propose a method to circumvent them by a simple modification of the\ndensity of state method. We first argue that the standard version of the\ndensity of state method, which is invented to solve the overlapping problem, is\neffective only for a certain `good' class of observables. We then modify it so\nas to solve the overlap problem for `bad' observables as well. While, in the\nstandard version of the density of state method, we usually constrain an\nobservable we are interested in, we fix a different observable in our new\nmethod which has a sharp peak at some particular value characterizing the\ncorrect vacuum of the target theory. In the finite-density QCD, such an\nobservable is the pion condensate. The average phase becomes vanishingly small\nas the value of the pion condensate becomes large, hence it is enough to\nconsider configurations with small values of pion condensate, where the zero\nmode does not appear. We demonstrate an effectiveness of our method by using a\ntoy model (the chiral random matrix theory) which captures the properties of\nfinite-density QCD qualitatively. We also argue how to apply our method to\nother theories including finite-density QCD. Although the example we study\nnumerically is based on the phase reweighting method, the same idea can be\napplied to more general reweighting methods and we show how this idea can be\napplied to find a possible QCD critical point.",
        "positive": "Quenched Heavy-Light Decay Constants: We present results for heavy-light decay constants, using both propagating\nquarks and the static approximation, in O(a)-improved, quenched lattice QCD. At\nbeta=6.2 on a 24^3x48 lattice we find f_D=185 +4-3(stat)+42-7(syst) MeV,\nf_B=160 +6-6 +53-19 MeV, f_{D_s}/f_D=1.18 +2-2 and f_{B_s}/f_B=1.22 +4-3, in\ngood agreement with earlier studies. From the static theory we obtain\nf_B^stat=253 +16-15 +105-14 MeV. We also present results from a simulation at\nbeta=6.0 on a 16^3x48 lattice, which are consistent with those at beta=6.2. In\norder to study the effects of improvement, we present a direct comparison of\nthe results using both the Wilson and the improved action at beta=6.0."
    },
    {
        "anchor": "The step scaling function of QCD at negative flavor number: As a computationally less costly test case for full QCD, we investigate an\nSU(3) Yang-Mills theory coupled to a bosonic spinor field. This theory\ncorresponds to QCD with minus two quark flavors and is known as the bermion\nmodel. Our central object of interest is the step scaling function which\ndescribes the scale evolution of the running coupling in the Schrodinger\nfunctional scheme. We develop a suitable algorithm for the simulation of O(a)\nimproved bermions and compare its performance with unimproved bermions and full\nQCD. We study in detail the lattice artefacts and the continuum extrapolation\nof the step scaling function from lattice simulations when improvement is used.\nOur results are compared to the unimproved bermion and dynamical fermion cases,\nand to renormalized perturbation theory in the continuum limit.\n  We also examine the step scaling function with massive quarks in the bermion\nmodel. According to the Appelquist-Carazzone theorem the contributions from\nmatter fields are expected to vanish for large masses, such that the step\nscaling function converges to the pure gauge theory case. If one wants to\nconnect non-perturbatively different effective theories with different numbers\nof active quarks over flavor thresholds, lattice artefacts should be reasonably\nsmall. In order to test the feasibility of such a method, we investigate the\nstep scaling function and its lattice artefacts for several values of the mass.",
        "positive": "Quark masses with Nf=2 twisted mass lattice QCD: We present the results of the recent high precision lattice calculation of\nthe average up/down, strange and charm quark masses performed by ETMC with Nf=2\ntwisted mass Wilson fermions. The analysis includes data at four values of the\nlattice spacing and pion masses as low as ~270 MeV, allowing for accurate\ncontinuum limit and chiral extrapolation. The strange and charm masses are\nextracted by using several methods, based on different observables: the kaon\nand the eta_s meson for the strange quark and the D, D_s and eta_c mesons for\nthe charm. The quark mass renormalization is carried out non-perturbatively\nusing the RI-MOM method. The results for the quark masses in the MSbar scheme\nread: m_ud(2 GeV)= 3.6(2) MeV, m_s(2 GeV)=95(6) MeV and m_c(m_c)=1.28(4) GeV.\nWe have also obtained the ratios m_s/m_ud=27.3(9) and m_c/m_s=12.0(3).\nMoreover, we provide the updated result for the bottom quark mass,\nm_b(m_b)=4.3(2) GeV, obtained using the method presented in 0909.3187\n[hep-lat]."
    },
    {
        "anchor": "The QCD Critical Point : marching towards continuum: We present results of our simulations of QCD with two light dynamical quarks\non a 32^3 X 8 lattice at a current quark mass tuned to have the Goldstone pion\nmass of about 230 MeV. Employing the Taylor expansion method we proposed\nearlier, we estimate the radius of convergence of the series for the baryonic\nsusceptibility by using terms up to eighth order. Together with our earlier\nresults, corresponding to the same physical parameters but on coarser lattices\nat respectively 1.33 times and twice the lattice cut-off (a), we were able to\nattempt a march towards the continuum limit.",
        "positive": "Four fermion condensates in $SU(2)$ Yang-Mills-Higgs theory on a lattice: We study a model of four reduced staggered fields transforming in the\nbifundamental representation of a $SU(2)\\times SU(2)$ symmetry group where just\none of the SU(2) factors is gauged. This field content and symmetries are\nsimilar to a Higgs-Yukawa model that has been studied recently. The key\nobservation in the latter work is that fermions acquire masses at strong\ncoupling via the formation of a symmetric four fermion condensate in contrast\nto the more usual symmetry breaking bilinear condensate seen in eg. NJL models.\nThe current work attempts to see whether this structure survives when the four\nfermi interactions are replaced by gauge interactions and to explore the\nresulting phase diagram."
    },
    {
        "anchor": "Fixed point actions from convolutional neural networks: Lattice gauge-equivariant convolutional neural networks (L-CNNs) can be used\nto form arbitrarily shaped Wilson loops and can approximate any gauge-covariant\nor gauge-invariant function on the lattice. Here we use L-CNNs to describe\nfixed point (FP) actions which are based on renormalization group\ntransformations. FP actions are classically perfect, i.e., they have no lattice\nartifacts on classical gauge-field configurations satisfying the equations of\nmotion, and therefore possess scale invariant instanton solutions. FP actions\nare tree-level Symanzik-improved to all orders in the lattice spacing and can\nproduce physical predictions with very small lattice artifacts even on coarse\nlattices. We find that L-CNNs are much more accurate at parametrizing the FP\naction compared to older approaches. They may therefore provide a way to\ncircumvent critical slowing down and topological freezing towards the continuum\nlimit.",
        "positive": "Lattice study on a tetra-quark state $T_{bb}$ in the HAL QCD method: We study a doubly-bottomed tetra-quark state $(bb\\bar{u}\\bar{d})$ with\nquantum number $I(J^P)=0(1^+)$, denoted by $T_{bb}$, in lattice QCD with the\nNon-Relativistic QCD (NRQCD) quark action for $b$ quarks. Employing\n$(2+1)$-flavor gauge configurations at $a \\approx 0.09$ {fm} on $32^3\\times 64$\nlattices, we have extracted the coupled channel potential between\n$\\bar{B}\\bar{B}^*$ and $\\bar{B}^* \\bar{B}^*$ in the HAL QCD method, which\npredicts an existence of a bound $T_{bb}$ below the $\\bar{B}\\bar{B}^*$\nthreshold. By extrapolating results at $m_\\pi\\approx 410,\\, 570,\\, 700$ {MeV}\nto the physical pion mass $m_\\pi\\approx140$ {MeV}, we obtain a biding energy\nwith its statistical error as $E_{\\rm binding}^{\\rm (single)} = 155(17)$ MeV\nand $E_{\\rm binding}^{\\rm (coupled)} = 83(10)$ MeV, where ``coupled\" means that\neffects due to virtual $\\bar{B}^* \\bar{B}^*$ states are included through the\ncoupled channel potential, while only a potential for a single\n$\\bar{B}\\bar{B}^*$ channel is used in the analysis for ``single\". A comparison\nshows that the effect from virtual $\\bar{B}^* \\bar{B}^*$ states is quite\nsizable to the binding energy of $T_{bb}$. We estimate systematic errors to be\n$\\pm 20$ MeV at most, which are mainly caused by the NRQCD approximation for\n$b$ quarks."
    },
    {
        "anchor": "Measuring interface tensions in 4d SU(N) lattice gauge theories: We propose a new algorithm to compute the order-order interface tension in\nSU(N) lattice gauge theories. The algorithm is trivially generalizable to a\nvariety of models, e.g., spin models. In the case N=3, via the perfect wetting\nhypothesis, we can estimate the order-disorder interface tension. In the case\nN=4, we study the ratio of dual k-tensions and find that it satisfies Casimir\nscaling down to T=1.2 T_c.",
        "positive": "Lattice QCD at finite baryon density using analytic continuation: We simulate lattice QCD with two flavors of Wilson fermions at imaginary\nbaryon chemical potential. Results for the baryon number density computed in\nthe confining and deconfining phases at imaginary baryon chemical potential are\nused to determine the baryon number density and higher cumulants at the real\nchemical potential via analytical continuation."
    },
    {
        "anchor": "Chromoelectric flux tubes and coherence length in QCD: The transverse profile of the chromoelectric flux tubes in SU(2) and SU(3)\npure gauge theories is analyzed by a simple variational ansatz using a strict\nanalogy with ordinary superconductivity. Our method allows to extract the\npenetration length and the coherence length of the flux tube.",
        "positive": "Bayesian approach to the first excited nucleon state in lattice QCD: We present preliminary results from the first attempt to reconstruct the\nspectral function in the nucleon and $\\Delta$ channels from lattice QCD data\nusing the maximum entropy method (MEM). An advantage of the MEM analysis is to\nenable us to access information of the excited state spectrum. Performing\nsimulations on two lattice volumes, we confirm the large finite size effect on\nthe first excited nucleon state in the lighter quark mass region."
    },
    {
        "anchor": "The twisted Polyakov loop coupling and the search for an IR fixed point: We report the nonperturbative behavior of the twisted Polyakov loop (TPL)\ncoupling constant for the SU(3) gauge theories defined by the ratio of Polyakov\nloop correlators in finite volume with twisted boundary condition. Carrying out\nthe numerical simulations, we determine the nonperturbative running coupling\nconstant in this renormalization scheme for Nf=12 SU(3) gauge theory.\n  According to the perturbative two loop analysis, the Nf=12 SU(3) gauge theory\nmight have a conformal fixed point in the infrared region. However, the recent\nlattice studies show controversial results for the existence of the fixed\npoint. We point out possible reasons of the controversy in previous works, and\npresent our careful study. Finally, we find the infrared fixed point (IRFP) and\ndiscuss the robustness of the nontrivial IRFP of many flavor system under the\nchange of the analysis method. This talk is based on the paper[1].",
        "positive": "The investigations of the $P$-wave $B_s$ states combining quark model\n  and lattice QCD in the coupled channel framework: Combining the quark model, the quark-pair-creation mechanism and $B^{(*)}\\bar\nK$ interaction, we have investigated the near-threshold $P$-wave $B_s$ states\nin the framework of the Hamiltonian effective field theory. With the heavy\nquark flavor symmetry, all the parameters are determined in the $D_s$ sector by\nfitting the lattice data. The masses of the bottom-strange partners of the\n$D^{*}_{s0}(2317)$ and $D^{*}_{s1}(2460)$ are predicted to be\n$M_{B^{*}_{s0}}=5730.2_{-1.5}^{+2.4}$ MeV and $M_{B^{*}_{s1}}=\n5769.6_{-1.6}^{+2.4}$ MeV, respectively, which are well consistent with the\nlattice QCD simulation. The two $P$-wave $B_s$ states are the mixtures of the\nbare $\\bar b s$ core and $B^{(*)}\\bar K$ component. Moreover, we find a\ncrossing point between the energy levels with and without the interaction\nHamiltonian in the finite volume spectrum in the $0^+$ case, which corresponds\nto a CDD (Castillejo-Dalitz-Dyson) zero in the $T$-matrix of the $B\\bar K$\nscattering. This CDD zero will help deepen the insights of the near-threshold\nstates and can be examined by future lattice calculation."
    },
    {
        "anchor": "Simulation of the Lattice QCD and Technological Trends in Computation: Simulation of Lattice QCD is a challenging computational problem. Currently,\ntechnological trends in computation show multiple divergent models of\ncomputation. We are witnessing homogeneous multi-core architectures, the use of\naccelerator on-chip or off-chip, in addition to the traditional architectural\nmodels.\n  On the verge of this technological abundance, assessing the performance\ntrade-offs of computing nodes based on these technologies is of crucial\nimportance to many scientific computing applications.\n  In this study, we focus on assessing the efficiency and the performance\nexpected for the Lattice QCD problem on representative architectures and we\nproject the expected improvement on these architectures and their impact on\nperformance for Lattice QCD. We additionally try to pinpoint the limiting\nfactors for performance on these architectures.",
        "positive": "Perfect Lattice Topology: The Quantum Rotor as a Test Case: Lattice actions and topological charges that are classically and quantum\nmechanically perfect (i.e. free of lattice artifacts) are constructed\nanalytically for the quantum rotor. It is demonstrated that the Manton action\nis classically perfect while the Villain action is quantum perfect. The\ngeometric construction for the topological charge is only perfect at the\nclassical level. The quantum perfect lattice topology associates a topological\ncharge distribution, not just a single charge, with each lattice field\nconfiguration. For the quantum rotor with the classically perfect action and\ntopological charge, the remaining cut-off effects are exponentially suppressed."
    },
    {
        "anchor": "SPHERICALLY SYMMETRIC RANDOM WALKS II. DIMENSIONALLY DEPENDENT CRITICAL\n  BEHAVIOR: A recently developed model of random walks on a $D$-dimensional\nhyperspherical lattice, where $D$ is {\\sl not} restricted to integer values, is\nextended to include the possibility of creating and annihilating random\nwalkers. Steady-state distributions of random walkers are obtained for all\ndimensions $D>0$ by solving a discrete eigenvalue problem. These distributions\nexhibit dimensionally dependent critical behavior as a function of the birth\nrate. This remarkably simple model exhibits a second-order phase transition\nwith a nontrivial critical exponent for all dimensions $D>0$.",
        "positive": "The 2+1 flavor topological susceptibility from the asqtad action at 0.06\n  fm: We report new data for the topological susceptibility computed on 2+1 flavor\ndynamical configurations with lattice spacing 0.06 fm, generated with the\nasqtad action. The topological susceptibility is computed by HYP smearing and\ncompared with rooted staggered chiral perturbation theory as the pion mass goes\nto zero. At 0.06 fm, the raw data is already quite close to the continuum\nextrapolated values obtained from coarser lattices. These results provide a\nfurther test of the asqtad action with rooted staggered flavors."
    },
    {
        "anchor": "Nucleon-$J/\u03c8$ and nucleon-$\u03b7_{c}$ scattering in $P_{c}$ pentaquark\n  channels from LQCD: The lattice QCD simulation of $NJ/\\psi$ and $N\\eta_c$ scattering is performed\nat $m_\\pi\\simeq 266~$MeV in channels with all possible $J^P$. This includes\n$J^P=3/2^\\pm$ and $5/2^\\pm$ where LHCb discovered $P_c(4380)$ and $P_c(4450)$\npentaquark states in proton$-J/\\psi$ decay. This is the first lattice\nsimulation that reaches the energies 4.3-4.5 GeV where pentaquarks reside.\nSeveral decay channels are open in this energy region and we explore the fate\nof $P_c$ in the one-channel approximation in this work. Energies of eigenstates\nare extracted for the nucleon-charmonium system at zero total momentum for all\nquantum numbers, i.e. six lattice irreducible representations. No significant\nenergy shifts are observed. The number of the observed lattice eigenstates\nagrees with the number expected for non-interacting charmonium and nucleon.\nThus, we do not find any strong indication for a resonance or a bound state in\nthese exotic channels within one-channel approximation. This possibly indicates\nthat the coupling of $NJ/\\psi $ channel with other two-hadron channels might be\nresponsible for $P_c$ resonances in experiment. One of the challenges of this\nstudy is that up to six degenerate $J/\\psi(p) N(-p)$ eigenstates are expected\nin the non-interacting limit due non-zero spins of $J/\\psi$ and N, and we\nestablish all of them in the spectra.",
        "positive": "Pion condensation at lower than physical quark masses: In QCD at large enough isospin chemical potential Bose-Einstein Condensation\n(BEC) takes place, separated from the normal phase by a phase transition. From\nprevious studies the location of the BEC line at the physical point is known.\nIn the chiral limit the condensation happens already at infinitesimally small\nisospin chemical potential for zero temperature according to chiral\nperturbation theory. The thermal chiral transition at zero density might then\nbe affected, depending on the shape of the BEC boundary, by its proximity. As a\nfirst step towards the chiral limit, we perform simulations of 2+1 flavors QCD\nat half the physical quark masses. The position of the BEC transition is then\nextracted and compared with the results at physical masses."
    },
    {
        "anchor": "Complex Langevin Dynamics and Supersymmetric Quantum Mechanics: Using complex Langevin method we probe the possibility of dynamical\nsupersymmetry breaking in supersymmetric quantum mechanics models with complex\nactions. The models we consider are invariant under the combined operation of\nparity and time reversal, in addition to supersymmetry. When actions are\ncomplex traditional Monte Carlo methods based on importance sampling fail.\nModels with dynamically broken supersymmetry can exhibit sign problem due to\nthe vanishing of the partition function. Complex Langevin method can\nsuccessfully evade the sign problem. Our simulations suggest that complex\nLangevin method can reliably predict the absence or presence of dynamical\nsupersymmetry breaking in these one-dimensional models with complex actions.",
        "positive": "Effects of staggered fermions and mixed actions on the scalar correlator: We provide the analytic predictions for the flavor non-singlet scalar\ncorrelator, which will enable determination of the scalar meson mass from the\nlattice scalar correlator. We consider simulations with 2+1 staggered sea\nquarks and staggered or chiral valence quarks. At small u/d masses the\ncorrelator is dominated by the bubble contribution, which is the intermediate\nstate with two pseudoscalar mesons. We determine the bubble contribution within\nStaggered and Mixed Chiral Perturbation Theory.\n  Its effective mass is smaller than the mass M_pi+M_eta, which is the lightest\nintermediate state in proper 2+1 QCD. The unphysical effective mass is a\nconsequence of the taste breaking that makes possible the intermediate state\nwith mass 2*M_pi. We find that the scalar correlator can be negative in the\nsimulations with mixed quark actions if the sea and valence quark masses are\ntuned by matching the pion masses M_{val,val}=M_{pi_5}."
    },
    {
        "anchor": "Vortices in SU(2) lattice gauge theory: We investigate some properties of thick vortices and thick monopoles in the\nSU(2) lattice gauge theory by inserting operators which create these\nexcitations. Some quantities associated with the dynamical behaviour of thick\nvortices and thick monopoles are studied. We measure the derivative of the free\nenergy of the vortex with respect to the coupling and we find that it falls\nexponentially with the cross sectional area of the vortex size. We also study\nthe monopole-monopole potential energy for thick and thin monopoles. Our\nresults suggest that vortices and monopoles of increasing thickness will play\nan important role in the large $\\beta$ limit.",
        "positive": "On the nature and order of the deconfining transition in QCD: The determination of the parameters of the deconfining transition in N_f=2\nQCD is discussed, and its relevance to the understanding of the mechanism of\ncolor confinement."
    },
    {
        "anchor": "Monte Carlo simulation of the SU(3) spin model with chemical potential\n  in a flux representation: We present a simulation of the SU(3) spin model with chemical potential using\na recently proposed flux representation. In this representation the complex\nphase problem is avoided and a Monte Carlo simulation in terms of the fluxes\nbecomes possible. We explore the phase diagram of the model as a function of\ntemperature and chemical potential.",
        "positive": "Lattice super-Yang-Mills using domain wall fermions in the chiral limit: Lattice N=1 super-Yang-Mills theory formulated using Ginsparg-Wilson fermions\nprovides a rigorous non-perturbative definition of the continuum theory that\nrequires no fine-tuning as the lattice spacing is reduced to zero. Domain wall\nfermions are one explicit scheme for achieving this and using them we have\nperformed large-scale Monte Carlo simulations of the theory for gauge group\nSU(2). We have measured the gaugino condensate, static potential, Creutz ratios\nand residual mass for several values of the domain wall separation L_s,\nfour-dimensional lattice volume, and two values of the gauge coupling. With\nthis data we are able to extrapolate the gaugino condensate to the chiral\nlimit, to express it in physical units, and to establish important benchmarks\nfor future studies of super-Yang-Mills on the lattice."
    },
    {
        "anchor": "Recent lattice results on finite temperature and density QCD, part I: We discuss recent progress made studies of bulk thermodynamics of strongly\ninteracting matter through lattice simulations of QCD with an almost physical\nlight and strange quark mass spectrum. We present results on the QCD equation\nof state at vanishing and non-vanishing quark chemical potential and show first\nresults on baryon number and strangeness fluctuations, which might be measured\nin event-by-event fluctuations in low energy runs at RHIC as well as at FAIR.",
        "positive": "Extracting the $\u03b7^\\prime$ meson mass from gluonic correlators in\n  lattice QCD: Calculation of the eta-prime meson mass is a notoriously difficult problem,\nas it requires evaluation of the disconnected diagram which is costly and\nnoisy. In this work, we use a gluonic operator to extract the eta-prime state\nafter smearing the link variables through the Wilson flow. With this choice,\none can avoid a large cancellation of pion contribution between the connected\nand disconnected diagrams. We obtain the eta-prime meson mass on lattices with\nthree different lattice spacings and two physical volumes, which allow us to\nestimate its continuum and large volume limits."
    },
    {
        "anchor": "Baryons with Ginsparg-Wilson quarks in a staggered sea: We determine the masses and magnetic moments of the octet baryons in chiral\nperturbation theory formulated for a mixed lattice action of Ginsparg-Wilson\nvalence quarks and staggered sea quarks. Taste-symmetry breaking does not occur\nat next-to-leading order in the combined lattice-spacing and chiral expansion.\nExpressions derived for masses and magnetic moments are required for addressing\nlattice artifacts in mixed-action simulations of these observables.",
        "positive": "$N_f=1+2$ mass dependence of the topological susceptibility: A massless up quark has long been proposed as a solution to the strong CP\nproblem. While this solution is sometimes thought to have been excluded, it is\nactually still ill-defined. In this work, we study the mass dependence of the\nphysical observable $\\chi_t$, the topological susceptibility. Assigning an\nunphysically large value to the down mass allows to be more sensitive to the\nnon-perturbative effects behind the $m_u=0$ ambiguity. Preliminary results are\npresented for four masses of clover fermions."
    },
    {
        "anchor": "Molecular dynamics for full QCD simulations with an improved action: I derive the equation of motion in molecular dynamics for doing full lattice\nQCD simulations with clover quarks. The even-odd preconditioning technique,\nexpected to significantly reduce the computational effort, is further developed\nfor the simulations.",
        "positive": "THE ELECTROWEAK PHASE TRANSITION ON THE LATTICE: The finite temperature electroweak phase transition is studied on the\nlattice. The results of the simulations obtained by the 3-dimensional effective\ntheories and the 4-dimensional SU(2)-Higgs model are reviewed."
    },
    {
        "anchor": "Dynamical Eightfold Way in Strongly Coupled Lattice QCD: We obtain from the quark-gluon dynamics, the Gell'Mann-Ne'eman eightfold way\nbaryons in an imaginary-time functional integral formulation of 3+1 lattice QCD\nin the strong coupling regime (small hopping parameter $\\kappa>0$). The model\nhas ${\\rm SU}(3)_c$ gauge and global ${\\rm SU}(3)_f$ flavor symmetries. In the\nsubspace of the physical Hilbert space of vectors with an odd number of quarks,\nthe baryons are associated with isolated dispersion curves in the\nenergy-momentum spectrum. The spin 1/2 octet and spin 3/2 decuplet baryons have\nasymptotic mass $-3\\ln\\kappa$ and for each baryon there is an antibaryon with\nidentical spectral properties. All the masses have the form\n$M=-3\\ln\\kappa-3\\kappa^3/4+\\kappa^6 r(\\kappa)$, with $r(\\kappa)$ real analytic.\nFor each member of the octet $r(\\kappa)$ is the same; for each member of the\ndecuplet, $r(0)$ is the same. So, there is no mass splitting within the octet,\nand within the decuplet up to and including ${\\cal O}(\\kappa^6)$. However,\nthere is an octet-decuplet mass difference of $3\\kappa^6/4+{\\cal O}(\\kappa^7)$.\nThe baryon and antibaryon spectrum is the only one up to near the meson-baryon\nthreshold of nearly $-5\\ln\\kappa$. A decoupling of hyperplane method is used to\nnaturally unveil the form of the baryon composite fields (no a priori\nguesswork), to show the existence of particles and their multiplicities using a\nspectral representation for the two-baryon correlation. We also obtain the\n(anti-)baryon dispersion curves which admit the representation $w(\\kappa,\\vec\np)= -3\\ln\\kappa -3\\kappa^3/4+\\kappa^3\\sum_{j=1,2,3} (1-\\cos ^j)/4+r(\\kappa,\\vec\np)$, where $r(\\kappa,\\vec p)$ is of ${\\cal O}(\\kappa^6)$.",
        "positive": "Gauge-fixing on the Lattice via Orbifolding: When fixing a covariant gauge, most popularly the Landau gauge, on the\nlattice one encounters the Neuberger 0/0 problem which prevents one from\nformulating a Becchi--Rouet--Stora--Tyutin symmetry on the lattice. Following\nthe interpretation of this problem in terms of Witten-type topological field\ntheory and using the recently developed Morse theory for orbifolds, we propose\na modification of the lattice Landau gauge via orbifolding of the gauge-fixing\ngroup manifold and show that this modification circumvents the orbit-dependence\nissue and hence can be a viable candidate for evading the Neuberger problem.\nUsing algebraic geometry, we also show that though the previously proposed\nmodification of the lattice Landau gauge via stereographic projection relies on\ndelicate departure from the standard Morse theory due to the non-compactness of\nthe underlying manifold, the corresponding gauge-fixing partition function\nturns out to be orbit independent for all the orbits except in a region of\nmeasure zero."
    },
    {
        "anchor": "Pseudo-Critical Temperature and Thermal Equation of State from $N_f=2$\n  Twisted Mass Lattice QCD: We report about the current status of our ongoing study of the chiral limit\nof two-flavor QCD at finite temperature with twisted mass quarks. We estimate\nthe pseudo-critical temperature $T_c$ for three values of the pion mass in the\nrange of $m_\\mathrm{PS} \\simeq 300$ and $500 \\mathrm{MeV}$ and discuss\ndifferent chiral scenarios.\n  Furthermore, we present first preliminary results for the trace anomaly,\npressure and energy density. We have studied several discretizations of\nEuclidean time up to $N_\\tau=12$ in order to assess the continuum limit of the\ntrace anomaly. From its interpolation we evaluate the pressure and energy\ndensity employing the integral method. Here, we have focussed on two pion\nmasses with $m_\\mathrm{PS} \\simeq 400$ and $700 \\mathrm{MeV}$.",
        "positive": "Lattice study of the chiral magnetic effect in a chirally imbalanced\n  matter: We investigate the chiral magnetic effect by lattice QCD with a chiral\nchemical potential. In a chirally imbalanced matter, we obtain a finite induced\ncurrent along an external magnetic field. We analyze the dependence on the\nlattice spacing, the temperature, the spatial volume, and the fermion mass. The\npresent result indicates that the continuum limit is important for the\nquantitative argument of the strength of the induced current."
    },
    {
        "anchor": "$ \u0394$ baryon spectroscopy in lattice QCD: A variational analysis is performed within the framework of lattice QCD to\nextract the masses of the spin-3/2 positive parity $ \\Delta^+ $ baryons,\nincluding radial excitations. $2+1$ flavour dynamical gauge-field\nconfigurations provided by the PACS-CS collaboration via the ILDG are\nconsidered. To improve our interpolator basis, we perform an iterative process\nof source and sink smearing and solve a generalised eigenvalue problem using\nthe resulting fermion operators. We obtain a clear signal for the ground and\nfirst excited states at a light quark mass corresponding to $ m_\\pi = 413 $\nMeV. Furthermore, we show that one can use the eigenvectors obtained in this\nmethod to investigate the nature of these states, allowing us to classify our\nresults as $ 1s $ and $ 2s $ states for the ground and first excited states\nrespectively. Finally, we briefly highlight the method of Hamiltonian Effective\nField Theory which can be used to make comparison with quark model\nexpectations.",
        "positive": "Simple Matrix Elements with Dynamical Fermions: We report on studies of simple matrix elements from simulations with two\nflavors of sea quarks, both staggered and Wilson. We show the decay constants\nof vector and pseudoscalar mesons. The effects of sea quarks are small. These\nsimulations are done at relatively large lattice spacing compared to most\nquenched studies."
    },
    {
        "anchor": "Renormalization of strongly coupled U(1) lattice gauge theories: Recent numerical studies of the 4D pure compact U(1) lattice gauge theory, I\nhave participated in, are reviewed. We look for a possibility to construct an\ninteresting nonperturbatively renormalizable continuum theory at the phase\ntransition between the confinement and Coulomb phases. First I describe the\nnumerical evidence, obtained from calculation of bulk observables on spherical\nlattices, that the theory has a non-Gaussian fixed point. Further the\ngauge-ball spectrum in the confinement phase is presented and its universality\nconfirmed. The unexpected result is that, in addition to massive states, the\ntheory contains a very light, possibly massless scalar gauge ball. I also\nsummarize results of studies of the compact U(1) lattice theory with fermion\nand scalar matter fields and point out that at strong coupling it represents a\nmodel of dynamical fermion mass generation.",
        "positive": "Performance optimizations for porting the openQ$^\\star$D package to GPUs: OpenQ$^\\star$D code has been used by the RC$^\\star$ collaboration for the\ngeneration of fully dynamical QCD+QED gauge configurations with C$^\\star$\nboundary conditions. In this talk, optimization of solvers provided with the\nopenQ$^\\star$D package relevant for porting the code on GPU-accelerated\nsupercomputing platforms is discussed. We present the analysis of the current\nimplementations of the GCR solver preconditioned with Schwarz alternating\nprocedure for ill-conditioned Dirac-operators. With the goal of enabling\nsupport for GPUs from various vendors, a novel method of adaptive\nCPU/GPU-hybrid implementation is proposed."
    },
    {
        "anchor": "O(a^2) improvement of the overlap-Dirac operator: We construct an $O(a^2)$-improved overlap-Dirac operator by designing an\nimproved overlap kernel, based on the Symanzik improvement program. Field\nrotation terms are also identified to improve off-shell amplitudes for both\nmassless and massive fermions. We check the free dispersion relation and\npropagator, and show that improved results become to close to the continuum\nones at low momentum region. We test the effect of improvement on the full-QCD\ngauge configuration and find that the relativistic dispersion relation is\nsatisfied within a few percent error up to $m_qa \\approx 0.5$.",
        "positive": "Distribution law of the Dirac eigenmodes in QCD: The near-zero modes of the Dirac operator are connected to spontaneous\nbreaking of chiral symmetry in QCD (SBCS) via the Banks-Casher relation. At the\nsame time the distribution of the near-zero modes is well described by the\nRandom Matrix Theory (RMT) with the Gaussian Unitary Ensemble (GUE). Then it\nhas become a standard lore that a randomness, as observed through distributions\nof the near-zero modes of the Dirac operator, is a consequence of SBCS. The\nhigher-lying modes of the Dirac operator are not affected by SBCS and are\nsensitive to confinement physics and related $SU(2)_{CS}$ and $SU(2N_F)$\nsymmetries. We study the distribution of the near-zero and higher-lying\neigenmodes of the overlap Dirac operator within $N_F=2$ dynamical simulations.\nWe find that both the distributions of the near-zero and higher-lying modes are\nperfectly described by GUE of RMT. This means that randomness, while consistent\nwith SBCS, is not a consequence of SBCS and is related to some more general\nproperty of QCD in confinement regime."
    },
    {
        "anchor": "New chiral lattice actions of the Borici-Creutz type: We generalize the Borici-Creutz action in such a way that the position of the\nsecond zero and the direction which breaks the hypercubic symmetry can be\narbitrarily chosen, and the action has still the correct continuum limit.\nMinimal doubling is guaranteed if the distance between the two zeros does not\nbecome too large. Special values of this distance could turn out to be\nparticularly convenient for efficient numerical simulations of minimally\ndoubled fermions.",
        "positive": "Vacuum structure as seen by overlap fermions: Three complementary views on the QCD vacuum structure, all based on\neigenmodes of the overlap operator, are reported in their interrelation: (i)\nspectral density, localization and chiral properties of the modes, (ii) the\npossibility of filtering the field strength with the aim to detect selfdual and\nantiselfdual domains and (iii) the various faces of the topological charge\ndensity, with and without a cutoff \\lambda_{\\rm cut} = O(\\Lambda_{QCD}). The\ntechniques are tested on quenched SU(3) configurations."
    },
    {
        "anchor": "Schwinger-Keldysh on the lattice: a faster algorithm and its application\n  to field theory: A new algorithm is developed allowing the Monte Carlo study of a 1 + 1\ndimensional theory in real time. The main algorithmic development is to avoid\nthe explicit calculation of the Jacobian matrix and its determinant in the\nupdate process. This improvement has a wide applicability and reduces the cost\nof the update in thimble-inspired calculations from O(N^3) to less than O(N^2).\nAs an additional feature, the algorithm leads to improved Monte Carlo\nproposals. We exemplify the use of the algorithm to the real time dynamics of a\nscalar {\\phi}^4 theory with weak and strong couplings.",
        "positive": "Lattice radial quantization by cubature: Basic aspects of a program to put field theories quantized in radial\ncoordinates on the lattice are presented. Only scalar fields are discussed.\nSimple examples are solved to illustrate the strategy when applied to the 3D\nIsing model."
    },
    {
        "anchor": "Hadronic Molecules in Lattice QCD: An adiabatic approximation is used to derive the binding potential between\ntwo heavy-light mesons in quenched SU(2)-colour lattice QCD. Analysis of the\nmeson-meson system shows that the potential is attractive at short- and\nmedium-range. The numerical data is consistent with the Yukawa model of pion\nexchange",
        "positive": "Euclidian 4d quantum gravity with a non-trivial measure term: We explore an extended coupling constant space of 4d regularized Euclidean\nquantum gravity, defined via the formalism of dynamical triangulations. We add\na measure term which can also serve as a generalized higher curvature term and\ndetermine the phase diagram and the geometries dominating in the various\nregions. A first order phase transition line is observed, but no second order\ntransition point is located. As a consequence we cannot attribute any continuum\nphysics interpretation to the so-called crinkled phase of 4d dynamical\ntriangulations."
    },
    {
        "anchor": "Improved Actions for QCD Thermodynamics on the Lattice: Finite cut-off effects strongly influence the thermodynamics of lattice\nregularized QCD at high temperature in the standard Wilson formulation. We\nanalyze the reduction of finite cut-off effects in formulations of the\nthermodynamics of $SU(N)$ gauge theories with three different $O(a^2)$ and\n$O(a^4)$ improved actions. We calculate the energy density and pressure on\nfinite lattices in leading order weak coupling perturbation theory\n($T\\rightarrow \\infty$) and perform Monte Carlo simulations with improved\n$SU(3)$ actions at non-zero $g^2$. Already on lattices with temporal extent\n$N_\\tau=4$ we find a strong reduction of finite cut-off effects in the high\ntemperature limit, which persists also down to temperatures a few times the\ndeconfinement transition temperature.",
        "positive": "Global Anomalies in chiral gauge theories on the lattice: We discuss the issue of global anomalies in chiral gauge theories on the\nlattice. In Luscher's approach, these obstructions make it impossible to define\nconsistently a fermionic measure for the path integral. We show that an SU(2)\ntheory has such a global anomaly if the Weyl fermion is in the fundamental\nrepresentation. The anomaly in higher representations is also discussed. We\nfinally show that this obstruction is the lattice analogue of the SU(2) anomaly\nfirst discovered by Witten."
    },
    {
        "anchor": "A faster method of computation of lattice quark number susceptibilities: We compute the quark number susceptibilities in two flavor QCD for staggered\nfermions by adding the chemical potential as a Lagrange multiplier for the\npoint-split number density term. Since lesser number of quark propagators are\nrequired at any order, this method leads to faster computations. We propose a\nsubtraction procedure to remove the inherent undesired lattice terms and check\nthat it works well by comparing our results with the existing ones where the\nelimination of these terms is analytically guaranteed. We also show that the\nratios of susceptibilities are robust, opening a door for better estimates of\nlocation of the QCD critical point through the computation of the tenth and\ntwelfth order baryon number susceptibilities without significant additional\ncomputational overload.",
        "positive": "Filtered overlap: speedup, locality, kernel non-normality and Z_A~1: We investigate the overlap operator with a UV filtered Wilson kernel. The\nfiltering leads to a better localization of the operator even on coarse\nlattices and with the untuned choice $\\rho=1$. Furthermore, the axial-vector\nrenormalization constant $Z_A$ is much closer to 1, reducing the mismatch with\nperturbation theory. We show that all these features persist over a wide range\nof couplings and that the details of filtering prove immaterial. We investigate\nthe properties of the kernel spectrum and find that the kernel non-normality is\nreduced. As a side effect we observe that for certain applications of the\nfiltered overlap a speed-up factor of 2-4 can be achieved."
    },
    {
        "anchor": "Probing the chiral weak Hamiltonian at finite volumes: Non-leptonic kaon decays are often described through an effective chiral weak\nHamiltonian, whose couplings (\"low-energy constants\") encode all\nnon-perturbative QCD physics. It has recently been suggested that these\nlow-energy constants could be determined at finite volumes by matching the\nnon-perturbatively measured three-point correlation functions between the weak\nHamiltonian and two left-handed flavour currents, to analytic predictions\nfollowing from chiral perturbation theory. Here we complete the analytic side\nin two respects: by inspecting how small (\"epsilon-regime\") and intermediate or\nlarge (\"p-regime\") quark masses connect to each other, and by including in the\ndiscussion the two leading Delta I = 1/2 operators. We show that the\nepsilon-regime offers a straightforward strategy for disentangling the\ncoefficients of the Delta I = 1/2 operators, and that in the p-regime\nfinite-volume effects are significant in these observables once the\npseudoscalar mass M and the box length L are in the regime ML \\lsim 5.0.",
        "positive": "Quark propagator with two flavors of O(a)-improved Wilson fermions: We compute the Landau gauge quark propagator from lattice QCD with two\nflavors of dynamical O(a)-improved Wilson fermions. The calculation is carried\nout with lattice spacings ranging from 0.06 fm to 0.08 fm, with quark masses\ncorresponding to pion masses of 420, 290 and 150 MeV, and for volumes of up to\n(4.5fm)^4. Our ensembles allow us to evaluate lattice spacing, volume and quark\nmass effects. We find that the quark wave function which is suppressed in the\ninfrared, is further suppressed as the quark mass is reduced, but the\nsuppression is weakened as the volume is increased. The quark mass function\nM(p^2) shows only a weak volume dependence. Hypercubic artefacts beyond O(a)\nare reduced by applying both cylinder cuts and H4 extrapolations. The H4\nextrapolation shifts the quark wave function systematically upwards but does\nnot perform well for the mass function."
    },
    {
        "anchor": "A Critical Surface of Chiral-invariant System with Gauge Boson and\n  Fermions: In the chirally-invariant context of the $U_{em}(1)$ gauge interaction and\nfour-fermion interactions for ordinary and mirror fermions, the Schwinger-Dyson\nequation for the fermion self-energy function is studied on a lattice. We find\nthat a sensible infrared limit can be defined on a critical surface, which is\nconsistent with the critical line found in the continuum theory.",
        "positive": "S-duality in lattice super Yang-Mills: We present a progress report on studying S-duality in lattice N=4 super\nYang-Mills. This is being done through a computation of 1/2-BPS states on the\nCoulomb branch, especially the 't Hooft--Polyakov monopole and the W boson. Key\nto these calculations is the use of twisted and C-periodic boundary conditions.\nIn addition we describe a variational method to disentangle operators with\ndefinite scaling dimension, particularly the Konishi and supergravity\noperators."
    },
    {
        "anchor": "Chiral expansion for lattice computations of B^{+} to D^{0}K^{+}\n  (\u03c0^{+}) and B^{+} to Dbar^{0} K^{+} (\u03c0^{+}) amplitudes: In this work, we suggest that hard-pion chiral perturbation theory may be\napplicable to the real parts of nonleptonic B^{+} to D^{0}P^{+} and B^{+} to\nDbar^{0}P^{+} (P=K,pi) decay amplitudes. These amplitudes play an important\nrole in the extraction of the angle gamma in the b-d unitarity triangle of the\nCKM matrix, and their real parts can be computed using lattice QCD. We\nconstruct the leading-order operator in the chiral expansion for these\nnonleptonic decays, and discuss the generic features of the\nnext-to-leading-order terms.",
        "positive": "$q\\bar{q}$-potential: a numerical study: We report the results of recent lattice simulations aimed at computing the\n$q$ and $\\bar q$ potential energies in the singlet and the octet (adjoint)\nrepresentation."
    },
    {
        "anchor": "Results from the MILC collaboration's SU(3) chiral perturbation theory\n  analysis: We present the status of the MILC collaboration's analysis of the light\npseudoscalar meson sector with SU(3) chiral fits. The analysis includes data\nfrom new ensembles with smaller lattice spacing, smaller light quark masses and\nlighter than physical strange quark masses. Our fits include the NNLO chiral\nlogarithms. We present results for decay constants, quark masses,\nGasser-Leutwyler low energy constants, and condensates in the two- and\nthree-flavor chiral limits.",
        "positive": "Focusing on the Fixed Point of 4D Simplicial Gravity: Our earlier renormalization group analysis of simplicial gravity is extended.\nA high statistics study of the volume and coupling constant dependence of the\ncumulants of the node distribution is carried out. It appears that the phase\ntransition of the theory is of first order, contrary to what is generally\nbelieved."
    },
    {
        "anchor": "Improvement and Taste Symmetry Breaking for Staggered Quarks: We compare several improved actions for staggered quarks. We study the effect\nof improvement on the taste changing interactions by calculating the splitting\nin the pion spectrum. We investigate the effect of the improvement on some\ntopological properties.",
        "positive": "Simplicial Quantum Gravity: This is my PhD thesis on four-dimensional simplicial quantum gravity using\nthe dynamical triangulation model. Most of the results we have published in\nseparate papers are collected here for your convenience. Some new results have\nbeen added as well. Besides these results this thesis also contains an\nintroduction to simplicial quantum gravity and a detailed description of my\ndynamical triangulation program for arbitrary dimension. Some small formal\nparts are in Dutch."
    },
    {
        "anchor": "Calculation of connected contributions to the S-matrix using duality\n  between lattice theories: The main aim of this work - to calculate 2- and 4-point connected\ncontributions to the $S$-matrix and correlation functions for the euclidean\nscalar field on the lattice with self-action $|\\phi|^{n}$ for $n>2$ with\ncoupling constant renormalised in a special way for arbitrary dimension. It is\nshown that the considered theory has a nontrivial continuous limit. A new\nmethod is proposed without the use of perturbation theory and diagrams. We have\nused the explored duality between different lattice field theories. After its\napplication, it turns out that it is possible to apply the saddle-point method\nto the generating functional, where the concentration of nodes of the initial\nlattice approximation acts as a large parameter. In addition to the connected\ncontributions to the $S$-matrix, the beta function is calculated. We have found\na critical point for the theory of $\\phi^{4k}$ in arbitrary dimension and a\nnontrivial mass gap of the interacting massless theory. We have received the\nmasses of bound and single-particle states of the interacting theory. The\nproposed method can be extend for application to QED and gauge theories, as\nwell as generalized to the arbitrary geometry of space. Though the way of\ncoupling rescaling is specific, it gives nontrivial theory with the majority of\nperturbatively expected effects.",
        "positive": "Real-time scattering in the lattice Schwinger model: Tensor network methods have demonstrated their suitability for the study of\nequilibrium properties of lattice gauge theories, even close to the continuum\nlimit. We use them in an out-of-equilibrium scenario, much less explored so\nfar, by simulating the real-time collisions of composite mesons in the lattice\nSchwinger model. Constructing wave-packets of vector mesons at different\nincoming momenta, we observe the opening of the inelastic channel in which two\nheavier mesons are produced and identify the momentum threshold. To detect the\nproducts of the collision in the strong coupling regime we propose local\nquantitites that could be measured in current quantum simulation platforms."
    },
    {
        "anchor": "No-Go Theorem of Leibniz Rule and Supersymmetry on the Lattice: An obstacle to realize supersymmetry on a lattice is the breakdown of Leibniz\nrule. We give a proof of a no-go theorem that it is impossible to construct a\nlattice field theory in an infinite lattice volume with any nontrivial field\nproducts and difference operators that satisfy the following three properties:\n(i) translation invariance, (ii) locality and (iii) Leibniz rule. We then\npropose a way to escape from the no-go theorem by introducing infinite flavors,\nand present a lattice model of N=2 supersymmetric quantum mechanics equipped\nwith the full exact supersymmetry.",
        "positive": "Hybrid Molecular Dynamics for Lattice Supersymmetry: We present the first results obtained with a Hybrid Molecular Dynamics\nalgorithm applied to an $N=1$ SU(2) Super-Yang--Mills on the lattice. We derive\nthe Hamilton equations of motion for the system with Wilson gluinos and present\npreliminary results on small lattices."
    },
    {
        "anchor": "Decay constants of P-wave heavy-light mesons from unquenched lattice QCD: We review some decays that require knowledge of the decay constants of\n$0^{+}$ heavy-light mesons. We compute the decay constants of P-wave\nheavy-light mesons from unquenched lattice QCD, with two degenerate flavours of\nsea quarks, at a single lattice spacing. The lightest sea quark mass used in\nthe calculation is a third of the strange quark mass. For the charm-strange\nmeson we obtain the decay constant: $f_{D_{s 0^+}} = 340(110)$ MeV using our\nnormalisation conventions. We obtain the $f_{P_s}^{static}$ (static-strange\nP-wave) decay constant as $302(39)$ MeV.",
        "positive": "Implications of gradient flow on the static force: We use gradient flow to compute the static force based on a Wilson loop with\na chromoelectric field insertion. The result can be compared on one hand to the\nstatic force from the numerical derivative of the lattice static energy, and on\nthe other hand to the perturbative calculation, allowing a precise extraction\nof the $\\Lambda_0$ parameter. This study may open the way to gradient flow\ncalculations of correlators of chromoelectric and chromomagnetic fields, which\ntypically arise in the nonrelativistic effective field theory factorization."
    },
    {
        "anchor": "Proton and neutron electromagnetic radii and magnetic moments from $N_f\n  = 2 + 1$ lattice QCD: We present results for the electromagnetic form factors of the proton and\nneutron computed on the $(2 + 1)$-flavor Coordinated Lattice Simulations (CLS)\nensembles including both quark-connected and -disconnected contributions. The\n$Q^2$-, pion-mass, lattice-spacing, and finite-volume dependence of our form\nfactor data is fitted simultaneously to the expressions resulting from\ncovariant chiral perturbation theory including vector mesons amended by models\nfor lattice artefacts. From these fits, we determine the electric and magnetic\nradii and the magnetic moments of the proton and neutron, as well as the Zemach\nradius of the proton. To assess the influence of systematic effects, we average\nover various cuts in the pion mass and the momentum transfer, as well as over\ndifferent models for the lattice-spacing and finite-volume dependence, using\nweights derived from the Akaike Information Criterion (AIC). Our results for\nthe magnetic moments of the proton and neutron are in good agreement with the\nexperimental values and have a relative precision of about $2.4\\,\\%$ and\n$3.7\\,\\%$, respectively. For the electromagnetic radii of the proton, we\nachieve a precision at the $1.5\\,\\%$ level.",
        "positive": "On the Logarithmic Triviality of Scalar Quantum Electrodynamics: Using finite size scaling and histogram methods we obtain numerical results\nfrom lattice simulations indicating the logarithmic triviality of scalar\nquantum electrodynamics, even when the bare gauge coupling is chosen large.\nSimulations of the non-compact formulation of the lattice abelian Higgs model\nwith fixed length scalar fields on $L^{4}$ lattices with $L$ ranging from $6$\nthrough $20$ indicate a line of second order critical points.\nFluctuation-induced first order transitions are ruled out. Runs of over ten\nmillion sweeps for each $L$ produce specific heat peaks which grow\nlogarithmically with $L$ and whose critical couplings shift with $L$ picking\nout a correlation length exponent of $0.50(5)$ consistent with mean field\ntheory. This behavior is qualitatively similar to that found in pure\n$\\lambda\\phi^{4}$."
    },
    {
        "anchor": "Continuum limit of hyperon vector coupling $f_1(0)$ from 2+1 flavor\n  domain wall QCD: We determine the hyperon vector couplings $f_1(0)$ for $\\Sigma^{-}\\rightarrow\nnl^-\\bar{\\nu_l}$ and $\\Xi^0\\rightarrow\\Sigma^{+}l^-\\bar{\\nu_l}$ semileptonic\ndecays in the continuum limit with (2+1)-flavors of dynamical domain-wall\nfermions, using the Iwasaki gauge action at two different lattice spacings of\n$a$=0.114(2) and 0.086(2) fm. A theoretical estimation of flavor SU(3)-breaking\neffect on the vector coupling is required to extract $V_{us}$ from the\nexperimental rate of hyperon beta decays. We obtain the vector couplings\n$f_1(0)$ for $\\Sigma\\rightarrow N$ and $\\Xi\\rightarrow \\Sigma$ beta-decays with\nan accuracy of less than one percent. We then find that lattice results of\n$f_1(0)$ combined with the best estimate of $|V_{us}|$ with imposing\nCabibbo-Kobayashi-Maskawa (CKM) unitarity are slightly deviated from the\nexperimental result of $|V_{us}f_1(0)|$ for the $\\Sigma\\rightarrow N$\nbeta-decay. This discrepancy can be attributed to an assumption made in the\nexperimental analysis on $|V_{us}f_1(0)|$, where the induced second-class form\nfactor $g_2$ is set to be zero regardless of broken SU(3) symmetry. We report\non this matter and then estimate the possible value of $g_2(0)$, which is\nevaluated from the experimental decay rate with our lattice result of $f_1(0)$\nunder the first-row CKM-unitarity condition.",
        "positive": "Revisiting the flux tube spectrum of 3d SU(2) lattice gauge theory: We perform a high precision measurement of the spectrum of the QCD flux tube\nin three-dimensional $\\SU(2)$ gauge theory at multiple lattice spacings. We\ncompare the results at large $q\\bar{q}$ separations $R$ to the spectrum\npredicted by the effective string theory, including the leading order boundary\nterm with a non-universal coefficient. We find qualitative agreement with the\npredictions from the leading order Nambu-Goto string theory down to small\nvalues of $R$, while, at the same time, observing the predicted splitting of\nthe second excited state due to the boundary term. On fine lattices and at\nlarge $R$ we observe slight deviations from the EST predictions for the first\nexcited state."
    },
    {
        "anchor": "Quenched penguins, the Delta I=1/2 rule, and epsilon'/epsilon: The transformation properties of strong penguin operators under the action of\nthe flavor group change when they are considered as operators in (partially)\nquenched QCD instead of the unquenched theory. An ambiguity arises, which is\nparameterized by new low-energy constants in the effective theory describing\nnon-leptonic kaon decays in the (partially) quenched setting. Here we summarize\nresults of the analysis for the complete set of three-flavor strong penguin\noperators, consisting of products of two left-handed flavor currents, or a\nleft- and a right-handed current. Our results imply that (partially) quenched\nlattice computations of the Delta I=1/2 rule and epsilon'/epsilon are both\naffected by ambiguities intrinsic to the use of the quenched approximation at\nleading order in the chiral expansion. The only exception is the partially\nquenched case with three light sea quarks, consistent with general\nexpectations. We also address the issue of quenched ambiguities in the case of\nan active charm, correcting and extending that in Phys. Rev. D 74, 014509\n(2006).",
        "positive": "Electromagnetic Splittings and Light Quark Masses: A method for computing electromagnetic properties of hadrons in lattice QCD\nis described. The electromagnetic field is introduced dynamically, using a\nnoncompact formulation. Employing enhanced electric charges, the dependence of\nthe pseudoscalar meson mass on the (anti)quark charges and masses can be\naccurately calculated. At $\\beta=5.7$ with Wilson action, the $\\pi^+-\\pi^0$\nsplitting is found to be $4.9(3)$ MeV. Using the measured $K^0-K^+$ splitting,\nwe also find $m_u/m_d = .512(6)$. Systematic errors are discussed. Preliminary\nresults for vector meson splittings are also presented.}"
    },
    {
        "anchor": "The Continuum Phase Diagram of the 2d Non-Commutative lambda phi**4\n  Model: We present a non-perturbative study of the lambda phi**4 model on a\nnon-commutative plane. The lattice regularised form can be mapped onto a\nHermitian matrix model, which enables Monte Carlo simulations. Numerical data\nreveal the phase diagram; at large lambda it contains a \"striped phase\", which\nis absent in the commutative case. We explore the question whether or not this\nphenomenon persists in a Double Scaling Limit (DSL), which extrapolates\nsimultaneously to the continuum and to infinite volume, at a fixed\nnon-commutativity parameter. To this end, we introduce a dimensional lattice\nspacing based on the decay of the correlation function. Our results provide\nevidence for the existence of a striped phase even in the DSL, which implies\nthe spontaneous breaking of translation symmetry. Due to the non-locality of\nthis model, this does not contradict the Mermin-Wagner Theorem.",
        "positive": "Algorithms for Disconnected Diagrams in Lattice QCD: Computing disconnected diagrams in Lattice QCD (operator insertion in a quark\nloop) entails the computationally demanding problem of taking the trace of the\nall to all quark propagator. We first outline the basic algorithm used to\ncompute a quark loop as well as improvements to this method. Then, we motivate\nand introduce an algorithm based on the synergy between hierarchical probing\nand singular value deflation. We present results for the chiral condensate\nusing a 2+1-flavor clover ensemble and compare estimates of the nucleon charges\nwith the basic algorithm."
    },
    {
        "anchor": "Singlet vs Nonsinglet Perturbative Renormalization factors of Staggered\n  Fermion Bilinears: In this paper we present the perturbative computation of the difference\nbetween the renormalization factors of flavor singlet\n($\\sum_f\\bar\\psi_f\\Gamma\\psi_f$, $f$: flavor index) and nonsinglet\n($\\bar\\psi_{f_1} \\Gamma \\psi_{f_2}, f_1 \\neq f_2$) bilinear quark operators\n(where $\\Gamma =\n\\mathbb{1},\\,\\gamma_5,\\,\\gamma_{\\mu},\\,\\gamma_5\\,\\gamma_{\\mu},\\,\n\\gamma_5\\,\\sigma_{\\mu\\,\\nu}$) on the lattice. The computation is performed to\ntwo loops and to lowest order in the lattice spacing, using Symanzik improved\ngluons and staggered fermions with twice stout-smeared links. The stout\nsmearing procedure is also applied to the definition of bilinear operators. A\nsignificant part of this work is the development of a method for treating some\nnew peculiar divergent integrals stemming from the staggered formalism. Our\nresults can be combined with precise simulation results for the renormalization\nfactors of the nonsinglet operators, in order to obtain an estimate of the\nrenormalization factors for the singlet operators. The results have been\npublished in Physical Review D.",
        "positive": "High temperature meson propagators with domain-wall quarks: We study the chiral properties of domain-wall quarks at high temperatures on\nan ensemble of quenched configurations. Low lying eigenmodes of the Dirac\noperator are calculated and used to check the extent to which the Atiyah-Singer\nindex theorem is obeyed on lattices with finite $N_5$. We calculate the\nconnected and disconnected screening propagators for the lowest mass scalar and\npseudoscalar mesons in the sectors of different topological charge and note\nthat they behave as expected. Separating out the would-be zero eigenmodes\nenables us to accurately estimate the disconnected propagators with far less\neffort than would be needed otherwise."
    },
    {
        "anchor": "A Study of Degenerate Four-quark states in SU(2) Lattice Monte Carlo: The energies of four-quark states are calculated for geometries in which the\nquarks are situated on the corners of a series of tetrahedra and also for\ngeometries that correspond to gradually distorting these tetrahedra into a\nplane. The interest in tetrahedra arises because they are composed of {\\bf\nthree } degenerate partitions of the four quarks into two two-quark colour\nsinglets. This is an extension of earlier work showing that geometries with\n{\\bf two} degenerate partitions (e.g.\\ squares) experience a large binding\nenergy. It is now found that even larger binding energies do not result, but\nthat for the tetrahedra the ground and first excited states become degenerate\nin energy. The calculation is carried out using SU(2) for static quarks in the\nquenched approximation with $\\beta=2.4$ on a $16^3\\times 32$ lattice. The\nresults are analysed using the correlation matrix between different euclidean\ntimes and the implications of these results are discussed for a model based on\ntwo-quark potentials.",
        "positive": "Determination of the Strong Coupling Constant by the ALPHA Collaboration: A high precision determination of the strong coupling constant in the MS-bar\nscheme at the Z-mass scale, using low energy quantities, namely pion/kaon decay\nconstants and masses, as experimental input is presented. The computation\nemploys two different massless finite volume renormalization schemes to\nnon-perturbatively trace the scale dependence of the respective running\ncouplings from a scale of about 200 MeV to 100 GeV. At the largest energies\nperturbation theory is reliable. At high energies the Schroedinger-Functional\nscheme is used, while the running at low and intermediate energies is computed\nin a novel renormalization scheme based on an improved gradient flow. Large\nvolume Nf=2+1 QCD simulations by CLS are used to set the overall scale. The\nresult is compared to world averages by FLAG and the PDG."
    },
    {
        "anchor": "Investigating the conformal behaviour of SU(2) with one adjoint Dirac\n  flavor: We present a major update on our investigations of SU(2) gauge theory with\none Dirac flavor in the adjoint representation on the lattice. In particular we\nconsider larger volumes, as well as four different values of the gauge\ncoupling. We provide results for the spectrum including gluonic, fermionic, and\nhybrid observables, Polyakov loops, and the anomalous dimension of the\nfermionic condensate from the Dirac mode number. These data confirm that the\ntheory is close to the lower boundary of the conformal window for adjoint\nfermions. Our investigations provide important insights regarding the\nrealization of different infrared scenarios that have been conjectured for this\ntheory.",
        "positive": "Chiral Phase Transition in Lattice QCD with Wilson Quarks: The nature of the chiral phase transition in lattice QCD is studied for the\ncases of 2, 3 and 6 flavors with degenerate Wilson quarks, mainly on a lattice\nwith the temporal direction extension $N_t=4$. We find that the chiral phase\ntransition is continuous for the case of 2 flavors, while it is of first order\nfor 3 and 6 flavors."
    },
    {
        "anchor": "Kaon $B$-parameters for Generic $\u0394S=2$ Four-Quark Operators in\n  Quenched Domain Wall QCD: We present a study of $B$-parameters for generic $\\Delta S=2$ four-quark\noperators in domain wall QCD. Our calculation covers all the $B$-parameters\nrequired to study the neutral kaon mixing in the standard model (SM) and beyond\nit. We evaluate one-loop renormalization factors of the operators employing the\nplaquette and Iwasaki gauge actions. Numerical simulations are carried out in\nquenched QCD with both gauge actions on $16^3\\times 32\\times 16$ and\n$24^3\\times 32\\times 16$ at the lattice spacing $1/a\\approx 2$GeV. We\ninvestigate the relative magnitudes of the non-SM $B$-parameters to the SM one,\nwhich are compared with the previous results obtained with the overlap and the\nclover quark actions.",
        "positive": "Sphaleron-Like Processes in a Realistic Heat Bath: We measure the diffusion rate of Chern-Simons number in the (1+1)-dimensional\nAbelian Higgs model interacting with a realistic heat bath for temperatures\nbetween 1/13 and 2/3 times the sphaleron energy. It is found that the measured\nrate is close to that predicted by the sphaleron approximation at the lower end\nof the temperature range considered but falls at least an order of magnitude\nshort of the sphaleron estimate at the upper end of that range. We show\nnumerically that the sphaleron approximation breaks down as soon as the\ngauge-invariant two-point function yields correlation length close to the\nsphaleron size."
    },
    {
        "anchor": "A new strategy for evaluating the LO HVP contribution to $(g-2)_\u03bc$ on\n  the lattice: A highly physical model of the subtracted $I=1$ vector polarization, obtained\nusing a dispersive representation with precise hadronic $\\tau$ decay data as\ninput, is used to investigate systematic issues in the lattice evaluation of\nthe leading order hadronic vacuum polarization contribution to the anomalous\nmagnetic moment of the muon. The model is also employed to study possible\nresolutions of these problems. A hybrid approach to analyzing lattice data,\ninvolving low-order Pad\\'e, low-degree conformal-variable polynomial, or\nsupplemented NNLO ChPT fits for $Q^2$ below $\\sim 0.1-0.2$ GeV$^2$ and direct\nnumerical integration of lattice data above this point, is shown to bring the\nsystematic issues identified under control at the sub-$1\\%$ level.",
        "positive": "Heat Bath Efficiency with Metropolis-Type Updating: We illustrate for 4D SU(2) and U(1) lattice gauge theory that sampling with a\nbiased Metropolis scheme is essentially equivalent to using the heat bath\nalgorithm. Only, the biased Metropolis method can also be applied when an\nefficient heat bath algorithm does not exist."
    },
    {
        "anchor": "QCD thermodynamics at zero and non-zero density: We present results on the QCD equation of state, obtained with two different\nimproved dynamical staggered fermion actions and almost physical quark masses.\nLattice cut-off effects are discussed in detail as results for three different\nlattice spacings are available now, i.e. results have been obtained on lattices\nwith temporal extent of $N_\\tau=4,6$ and 8. Furthermore we discuss the Taylor\nexpansion approach to non-zero baryon chemical potential by means of an\nexpansion of the pressure. We use the expansion coefficients to calculate\nvarious fluctuations and correlations among hadronic charges. We find that the\ncorrelations reproduce the qualitative behavior of the resonance gas model\nbelow $T_c$ and start to agree with the free gas predictions for $T\\gsim\n1.5T_c$.",
        "positive": "Nucleon structure functions from dynamical (2+1)-flavor domain wall\n  fermions: We report lattice-volume independence of low moments of nucleon structure\nfunctions from the coarse RIKEN-BNL-Columbia (RBC) and UKQCD joint dynamical\n(2+1)-flavor domain-wall fermions (DWF) ensembles at the lattice cut off of\n(a^{-1}\\sim1.7) GeV. The isovector quark momentum fraction, (< x >_{u-d}), and\nhelicity fraction, (< x >_{\\Delta u - \\Delta d}), both fully non-perturbatively\nrenormalized are studied on two spatial volumes of ((\\sim {\\rm 2.7 fm})^3) and\n((\\sim {\\rm 1.8 fm})^3). Their naturally renormalized ratio, (< x >_{u-d}/< x\n>_{\\Delta u - \\Delta d}), is not affected by any finite-size effect. It does\nnot depend strongly on light quark mass and does agree well with the\nexperiment. The respective absolute values, fully non-perturbatively\nrenormalized, do not show any finite-size effect either. They show trending\ntoward the respective experimental values at the lightest up- and down-quark\nmass. This trending down to the experimental values appears to be a real\nphysical effect driven by lighter quarks. The observations are in contrast to\nthe huge finite-size effect seen in the axial-current form factors."
    },
    {
        "anchor": "Glueball Mass Predictions of the Valence Approximation to Lattice QCD: We evaluate the infinite volume, continuum limit of glueball masses in the\nvalence (quenched) approximation to lattice QCD. For the lightest scalar and\ntensor states we obtain masses of $1648 \\pm 58$ MeV and $2267 \\pm 104$ MeV,\nrespectively.",
        "positive": "Quenched chiral perturbation theory for baryon form factors: A new intuitive method for the rapid calculation of the leading nonanalytic\nbehavior of hadronic observables in quenched chiral perturbation theory is\npresented. After proving the technique in a consideration of baryon masses, the\nquenched magnetic moments of octet baryons are addressed. The technique\nprovides a separation of magnetic moment contributions into full, sea, valence\nand quenched valence contributions, the latter being the conventional view of\nthe quenched approximation. Both baryon mass and meson mass violations of\nSU(3)-flavor symmetry are accounted for. A comprehensive examination of the\nindividual quark-sector contributions to octet baryon magnetic moments reveals\nthat the u-quark contribution to the proton magnetic moment provides an optimal\nopportunity to directly view nonanalytic behavior associated with the quenched\nmeson cloud of baryons in the quenched approximation."
    },
    {
        "anchor": "Conformal Behavior in QCD: We give a new perspective on the properties of quarks and gluons at finite\ntemperature T in N_f = 2 ~ 6 QCD. We point out the existence of an IR fixed\npoint for the gauge coupling constant at T>T_c (T_c is the chiral phase\ntransition temperature). Based on this observation we predict theoretically and\nverify numerically that the correlation functions of a meson G(t) at T/T_c > 1\ndecay with a power-law corrected Yukawa-type decaying form, G(t)=c exp(-m\nt)/t^alpha in the \"conformal region\" defined by m < c Lambda_IR, where\nLambda_IR is the IR cutoff, m is the characteristic scale of the spectrum in\nthe meson cannel and c is a constant of order 1. The decaying form is the\ncharacteristics of conformal theories with an IR cutoff. We discuss in detail\nhow the resulting hyper scaling relation of physical observables may modify the\nexisting argument about the order of the chiral phase transition in the N_f=2\ncase.",
        "positive": "On the fourth root prescription for dynamical staggered fermions: With the aim of resolving theoretical issues associated with the fourth root\nprescription for dynamical staggered fermions in Lattice QCD simulations, we\nconsider the problem of finding a viable lattice Dirac operator D such that\n(det D_{staggered})^{1/4} = det D. Working in the flavour field representation\nwe show that in the free field case there is a simple and natural candidate D\nsatisfying this relation, and we show that it has acceptable locality behavior:\nexponentially local with localisation range vanishing ~ (a/m)^{1/2} for lattice\nspacing a -> 0. Prospects for the interacting case are also discussed, although\nwe do not solve this case here."
    },
    {
        "anchor": "Anisotropic Membranes: We describe the statistical behavior of anisotropic crystalline membranes. In\nparticular we give the phase diagram and critical exponents for phantom\nmembranes and discuss the generalization to self-avoiding membranes.",
        "positive": "Large-Nc equivalence and the sign problem at finite baryon density: QCD with a finite baryon chemical potential, despite its importance, is not\nwell understood because the standard lattice QCD simulation is not applicable\ndue to the sign problem. Although QCD-like theories which do not suffer from\nthe sign problem have been studied intensively, relation to QCD with a finite\nbaryon chemical potential was not clear. This paper introduces large-$N_c$\nequivalences between QCD and various QCD-like theories. These equivalences lead\nus to a unified viewpoint for QCD with baryon and isospin chemical potentials,\n$SO(2N_c)$ and $Sp(2N_c)$ gauge theories, QCD with adjoint matters and\ntwo-color QCD. In particular QCD with the baryon chemical potential is\nlarge-$N_c$ equivalent to its phase quenched version in a certain parameter\nregion, which is relevant for heavy ion collision experiments. All previous\nsimulation results which study the effect of the phase confirm the phase quench\napproximation is quantitatively good already at Nc=3; it is so good that often\ntwo theories give the same value within error. Therefore the phase quenched\nsimulation is the best strategy for the QCD critical point search. At small\nvolume one can study a tiny 1/Nc effect by the phase reweighting; the large-Nc\nequivalence guarantees that the phase reweighing method works without suffering\nfrom the overlapping problem."
    },
    {
        "anchor": "Lattice fermions with gauge noninvariant measure: We define Weyl fermions on a finite lattice in such a way that in the path\nintegral the action is gauge invariant but the functional measure is not. Two\nvariants of such a formulation are tested in perturbative calculation of the\nfermion determinant in chiral Schwinger model. We find that one of these\nvariants ensures restoring the gauge invariance of the nonanomalous part of the\ndeterminant in the continuum limit. A `perfect' perturbative regularization of\nthe chiral fermions is briefly discussed.",
        "positive": "Large N: Some mysterious features of the strong interactions become easily understood\nif our usual QCD with N=3 is `close to' SU(oo) and if the latter theory is\nconfining. N=oo theories are theoretically simpler; in particular there has\nbeen much progress in constructing weak-coupling duals in string theory. In\nthis poster I will describe some of the things that recent lattice calculations\ntell us about the large-N limit of SU(N) gauge theories in 3+1 dimensions. The\nfocus is on confinement, how close SU(oo) is to SU(3), new stable strings at\nlarger N, the Pomeron, deconfinement, topology, 't Hooft string tensions. I\nalso allude to other topics, such as the high-T pressure deficit, chiral\nphysics and the phases of the theory."
    },
    {
        "anchor": "Phases of 2d massless QCD with qubit regularization: We investigate the possibility of reproducing the continuum physics of 2d\nSU(N) gauge theory coupled to a single flavor of massless Dirac fermions using\nqubit regularization. The continuum theory is described by N free fermions in\nthe ultraviolet (UV) and a coset Wess-Zumino-Witten (WZW) model in the infrared\n(IR). In this work, we explore how well these features can be reproduced using\nthe Kogut-Susskind Hamiltonian with a finite-dimensional link Hilbert space and\na generalized Hubbard coupling. Using strong coupling expansions, we show that\nour model exhibits a gapped dimer phase and another phase described by a\nspin-chain. Furthermore, for N=2, using tensor network methods, we show that\nthere is a second-order phase transition between these two phases. The critical\ntheory at the transition can be understood as an SU(2)_1 WZW model, using which\nwe determine the phase diagram of our model quantitatively. Using the\nconfinement properties of the model we argue how the UV physics of free\nfermions could also emerge, but may require further modifications to our model.",
        "positive": "Positivity violation for the lattice Landau gluon propagator: We present explicit numerical evidence of reflection-positivity violation for\nthe lattice Landau gluon propagator in three-dimensional pure SU(2) gauge\ntheory. We use data obtained at very large lattice volumes (V = 80^3, 140^3)\nand for three different lattice couplings in the scaling region (beta = 4.2,\n5.0, 6.0). In particular, we observe a clear oscillatory pattern in the\nreal-space propagator C(t). We also verify that the (real-space) data show good\nscaling in the range t \\in [0,3] fm and can be fitted using a Gribov-like form.\nThe violation of positivity is in contradiction with a stable-particle\ninterpretation of the associated field theory and may be viewed as a\nmanifestation of confinement."
    },
    {
        "anchor": "Properties of Abelian Monopoles in SU(2) Lattice Gluodynamics: We discuss some properties of abelian monopoles in the Maximal Abelian\nprojection of the SU(2) lattice gluodynamics. We show that in the maximal\nabelian projection abelian monopoles carry fluctuating electric charge and that\nthe monopole currents are correlated with the magnetic and the electric parts\nof the SU(2) action density.",
        "positive": "Towards higher order numerical stochastic perturbation computation\n  applied to the twisted Eguchi-Kawai model: We have evaluated perturbation coefficients of Wilson loops up to $O(g^8)$\nfor the four-dimensional twisted Eguchi-Kawai model using the numerical\nstochastic perturbation theory (NSPT) in arXiv:1902.09847. In this talk we\npresent a progress report on the higher order calculation up to $O(g^{63})$,\nfor which we apply a fast Fourier transformation (FFT) based convolution\nalgorithm to the multiplication of polynomial matrices in the NSPT aiming for\nhigher order calculation. We compare two implementations with the CPU-only\nversion and the GPU version of the FFT based convolution algorithm, and find a\nfactor 9 improvement on the computational speed of the NSPT algorithm with\nSU($N=225$) at $O(g^{31})$. The perturbation order dependence of the\ncomputational time, we investigate it up to $O(g^{63})$, shows a mild scaling\nbehavior on the truncation order."
    },
    {
        "anchor": "Order, Disorder and Confinement: Studying the order of the chiral transition for $N_f=2$ is of fundamental\nimportance to understand the mechanism of color confinement. We present results\nof a numerical investigation on the order of the transition by use of a novel\nstrategy in finite size scaling analysis. The specific heat and a number of\nsusceptibilities are compared with the possible critical behaviours. A second\norder transition in the O(4) and O(2) universality classes are excluded.\nSubstantial evidence emerges for a first order transition. Results are in\nagreement with those found by studying the scaling properties of a disorder\nparameter related to the dual superconductivity mechanism of color confinement.",
        "positive": "Baryon-Baryon Interactions in the Flavor SU(3) Limit from Full QCD\n  Simulations on the Lattice: We investigate baryon-baryon (BB) interactions in the 3-flavor full QCD\nsimulations with degenerate quark masses for all flavors. The BB potentials in\nthe orbital S-wave are extracted from the Nambu-Bethe-Salpeter wave functions\nmeasured on the lattice. We observe strong flavor-spin dependences of the BB\npotentials at short distances. In particular, a strong repulsive core exists in\nthe flavor-octet and spin-singlet channel (the 8_s representation), while an\nattractive core appears in the flavor singlet channel (the 1 representation).\nWe discuss a relation of such flavor-spin dependence with the Pauli exclusion\nprinciple in the quark level. Possible existence of an H-dibaryon resonance\nabove the Lambda-Lambda threshold is also discussed."
    },
    {
        "anchor": "Axial, Scalar and Tensor Charges of the Nucleon from 2+1+1-flavor\n  Lattice QCD: We present results for the isovector axial, scalar and tensor charges\n$g^{u-d}_A$, $g^{u-d}_S$ and $g^{u-d}_T$ of the nucleon needed to probe the\nStandard Model and novel physics. The axial charge is a fundamental parameter\ndescribing the weak interactions of nucleons. The scalar and tensor charges\nprobe novel interactions at the TeV scale in neutron and nuclear\n$\\beta$-decays, and the flavor-diagonal tensor charges $g^{u}_T$, $g^{d}_T$ and\n$g^{s}_T$ are needed to quantify the contribution of the quark electric dipole\nmoment (EDM) to the neutron EDM. The 9 ensembles, generated by the MILC\nCollaboration using the HISQ action with 2+1+1 dynamical flavors, span three\nlattice spacings $a \\approx 0.06, 0.09$ and 0.12 fm and light-quark masses\ncorresponding to the pion masses $M_\\pi \\approx 135, 225$ and 315 MeV.\nHigh-statistics estimates on five ensembles using the all-mode-averaging method\nallow us to quantify all systematic uncertainties and perform a simultaneous\nextrapolation in the lattice spacing, lattice volume and light-quark masses for\nthe connected contributions. Our final estimates, in the $\\overline{\\text{MS}}$\nscheme at 2 GeV, of the isovector charges are $g_A^{u-d} = 1.195(33)(20)$,\n$g_S^{u-d} = 0.97(12)(6) $ and $g_T^{u-d} = 0.987(51)(20)$. The first error\nincludes statistical and all systematic uncertainties except that due to the\nextrapolation Ansatz, which is given by the second error estimate. Combining\nour estimate for $g_S^{u-d}$ with the difference of light quarks masses\n$(m_d-m_u)^{\\rm QCD}=2.67(35)$ MeV given by FLAG, we obtain $(M_N-M_P)^{\\rm\nQCD} = 2.59(49)$ MeV. Estimates of the connected part of the flavor-diagonal\ntensor charges of the proton are $g^{u}_T=0.792(42)$ and $g^{d}_T=-0.194(14)$.\nCombining our new estimates with precision low-energy experiments, we update\nconstraints on novel scalar and tensor interactions, $\\epsilon_{S,T}$, at the\nTeV scale.",
        "positive": "Decoupling a Fermion Whose Mass Comes from a Yukawa Coupling:\n  Nonperturbative Considerations: Perturbative analyses seem to suggest that fermions whose mass comes solely\nfrom a Yukawa coupling to a scalar field can be made arbitrarily heavy, while\nthe scalar remains light. The effects of the fermion can be summarized by a\nlocal effective Lagrangian for the light degrees of freedom. Using weak\ncoupling and large N techniques, we present a variety of models in which this\nconclusion is shown to be false when nonperturbative variations of the scalar\nfield are considered. The heavy fermions contribute nonlocal terms to the\neffective action for light degrees of freedom. This resolves paradoxes about\nanomalous and nonanomalous symmetry violation in these models. Application of\nthese results to lattice gauge theory imply that attempts to decouple lattice\nfermion doubles by the method of Swift and Smit cannot succeed, a result\nalready suggested by lattice calculations."
    },
    {
        "anchor": "FK/Fpi in full QCD: We determine the ratio FK/Fpi in QCD with Nf=2+1 flavors of sea quarks, based\non a series of lattice calculations with three different couplings, large\nvolumes and a simulated pion mass reaching down to about 190 MeV. We obtain\nFK/Fpi = 1.192 +- 0.007(stat) +- 0.006(sys) with all the sources of systematic\nuncertainty under control.",
        "positive": "On the phase structure of a chiral invariant Higgs-Yukawa model: In the past the construction of Higgs-Yukawa models on the lattice was\nblocked by the lack of a consistent definition of a chiral invariant Yukawa\ncoupling term. Here, we consider a chiral invariant Higgs-Yukawa model based on\nthe overlap operator, realized by the Neuberger-Dirac operator. As a first step\ntowards a numerical examination of this model we study its phase diagram by\nmeans of an analytic 1/N-expansion, which is possible for small and for large\nvalues of the Yukawa coupling constant. In the case of strong Yukawa couplings\nthe model effectively becomes an O(4)-symmetric non-linear sigma-model."
    },
    {
        "anchor": "Magnetic catalysis (and inverse catalysis) at finite temperature in\n  two-color lattice QCD: Two-color lattice QCD with N_f=4 staggered fermion degrees of freedom (no\nrooting trick is applied) with equal electric charge q is studied in a\nhomogeneous magnetic background field B and at non-zero temperature T. In order\nto circumvent renormalization as a function of the bare coupling we apply a\nfixed-scale approach. We study the influence of the magnetic field on the\ncritical temperature. At rather small pseudo-scalar meson mass ($m_{\\pi}\n\\approx 175 \\mathrm{MeV} \\approx T_c(B=0)$) we confirm a monotonic rise of the\nquark condensate $<\\bar{\\psi} \\psi>$ with increasing magnetic field strength,\ni.e. magnetic catalysis, as long as one is staying within the confinement or\ndeconfinement phase. In the transition region we find indications for a\nnon-monotonic behavior of $T_c(B)$ at low magnetic field strength ($qB<0.8\n\\mathrm{GeV}^2$) and a clear rise at stronger magnetic field. The conjectured\nexistence of a minimum value $T_c(B^{*}) < T_c(B=0)$ would leave a temperature\nwindow for a decrease of $<\\bar{\\psi} \\psi>$ with rising $B$ (inverse magnetic\ncatalysis) also in the present model.",
        "positive": "A note on Rome-Southampton Renormalization with Smeared Gauge Fields: We have calculated continuum limit step scaling functions of bilinear and\nfour-fermion operators renormalized in a Rome-Southampton scheme using various\nsmearing prescriptions for the gauge field. Also, for the first time, we have\ncalculated non-perturbative anomalous dimensions of operators renormalized in a\nRome-Southampton scheme. The effect of such smearing first enters connected\nfermionic correlation functions via radiative corrections. We use off-shell\nrenormalisation as a probe, and observe that the upper edge of the\nRome-Southampton window is reduced by link smearing. This can be interpreted as\narising due to the fermions decoupling from the high momentum gluons and we\nobserve that the running of operators with the scale at large lattice momenta\nshows enhanced lattice artefacts. We find that the effect is greater for HEX\nsmearing than for Stout smearing, but that in both cases additional care must\nbe taken when using off-shell renormalisation with smeared gauge fields\ncompared to thin link simulations."
    },
    {
        "anchor": "Density of states approach for lattice field theory with topological\n  terms: We discuss a new density of states (DoS) approach to solve the complex action\nproblem that is caused by topological terms. The key ingredient is to use open\nboundary conditions for (at least) one of the directions, such that the\nquantization of the topological charge is lifted and the density becomes a\nregular function. We employ the DoS FFA method and compute the density of\nstates as a function of the topological charge. Subsequent integration with\nsuitable factors gives rise to the observables we are interested in. We here\nexplore two test cases: U(1) lattice gauge theory in two dimensions, and SU(2)\nlattice gauge theory in four dimensions. Since the 2-d case has an exact\nsolution we may use it to assess the method, in particular to establish the\nequivalence of the open boundary results with the usual choice of periodic\nboundary conditions. The SU(2) case is a first step of developing the\ntechniques towards their eventual application in full QCD.",
        "positive": "The Gluon Chain Model Revisited: I describe how the gluon chain model of QCD string formation meets a number\nof criteria which are required of any theory of the confining force, including:\nthe correct center dependence and (at large-N) Casimir scaling of the string\ntension, the logarithmic broadening of the QCD flux tube, and the existence of\na Luscher term in the static quark potential."
    },
    {
        "anchor": "Non-perturbative renormalisation of left-left four-fermion operators\n  with Neuberger fermions: We outline a general strategy for the non-perturbative renormalisation of\ncomposite operators in discretisations based on Neuberger fermions, via a\nmatching to results obtained with Wilson-type fermions. As an application, we\nconsider the renormalisation of the four-quark operators entering the Delta S=1\nand Delta S=2 effective Hamiltonians. Our results are an essential ingredient\nfor the determination of the low-energy constants governing non-leptonic kaon\ndecays.",
        "positive": "Roberge-Weiss endpoint at the physical point of $N_f = 2+1$ QCD: We study the phase diagram of $N_f = 2+1$ QCD in the $T - \\mu_B$ plane and\ninvestigate the critical point corresponding to the onset of the Roberge-Weiss\ntransition, which is found for imaginary values of $\\mu_B$. We make use of\nstout improved staggered fermions and of the tree level Symanzik gauge action,\nand explore four different sets of lattice spacings, corresponding to $N_t =\n4,6,8,10$, and different spatial sizes, in order to assess the universality\nclass of the critical point. The continuum extrapolated value of the endpoint\ntemperature is found to be $T_{\\rm RW} = 208(5)$ MeV, i.e. $T_{\\rm\n  RW}/T_c \\sim 1.34(7)$, where $T_c$ is the chiral pseudocritical temperature\nat zero chemical potential, while our finite size scaling analysis, performed\non $N_t = 4$ and $N_t = 6$ lattices, provides evidence for a critical point in\nthe $3d$ Ising universality class."
    },
    {
        "anchor": "QCD at Zero Baryon Density and the Polyakov Loop Paradox: We compare the grand canonical partition function at fixed chemical potential\nmu with the canonical partition function at fixed baryon number B, formally and\nby numerical simulations at mu=0 and B=0 with four flavours of staggered\nquarks. We verify that the free energy densities are equal in the thermodynamic\nlimit, and show that they can be well described by the hadron resonance gas at\nT < T_c and by the free fermion gas at T>T_c.\n  Small differences between the two ensembles, for thermodynamic observables\ncharacterising the deconfinement phase transition, vanish with increasing\nlattice size. These differences are solely caused by contributions of non-zero\nbaryon density sectors, which are exponentially suppressed with increasing\nvolume. The Polyakov loop shows a different behaviour: for all temperatures and\nvolumes, its expectation value is exactly zero in the canonical formulation,\nwhereas it is always non-zero in the commonly used grand-canonical formulation.\nWe clarify this paradoxical difference, and show that the non-vanishing\nPolyakov loop expectation value is due to contributions of non-zero triality\nstates, which are not physical, because they give zero contribution to the\npartition function.",
        "positive": "Hybrid static potentials in SU(2) lattice gauge theory at short\n  quark-antiquark separations: We compute hybrid static potentials in SU(2) lattice gauge theory using a\nmultilevel algorithm and three different small lattice spacings. The resulting\nstatic potentials, which are valid for quark-antiquark separations as small as\n0.05 fm, are important e.g. when computing masses of heavy hybrid mesons in the\nBorn-Oppenheimer approximation. We also discuss and exclude possible systematic\nerrors from topological freezing, the finite lattice volume and glueball\ndecays."
    },
    {
        "anchor": "Non-compact QED3 at finite temperature: the confinement-deconfinement\n  transition: The confinement-deconfinement phase transition is explored by lattice\nnumerical simulations in non-compact (2+1)-dimensional quantum electrodynamics\nwith massive fermions at finite temperature. The existence of two phases, one\nwith and the other without confinement of fractional charges, is related to the\nrealization of the Z symmetry. The order parameter of this transition can be\nclearly identified. We show that it is possible to detect the critical\ntemperature for a given value of the fermion mass, by exploiting suitable\nlattice operators as probes of the Z symmetry. Moreover, the large-distance\nbehavior of the correlation of these operators permits to distinguish the phase\nwith Coulomb-confinement from the Debye-screened phase. The resulting scenario\nis compatible with the existence of a Berezinsky-Kosterlitz-Thouless\ntransition. Some investigations are presented on the possible relation between\nchiral and deconfinement transitions and on the role of ``monopoles''.",
        "positive": "Chiral unitary theory of scalar mesons in a finite volume: We develop a scheme for the extraction of the properties of the scalar mesons\n$f_0(600)$, $f_0(980)$, and $a_0(980)$ from lattice QCD data. This scheme is\nbased on a two-channel chiral unitary approach with fully relativistic\npropagators in a finite volume. In order to discuss the feasibility of finding\nthe mass and width of the scalar resonances, we analyze synthetic lattice data\nwith a fixed error assigned, and show that the framework can be indeed used for\nan accurate determination of resonance pole positions in the multi-channel\nscattering."
    },
    {
        "anchor": "Light-cone distribution amplitudes of octet baryons from lattice QCD: We present lattice QCD results for the wave function normalization constants\nand the first moments of the distribution amplitudes for the lowest-lying\nbaryon octet. The analysis is based on a large number of $N_f=2+1$ ensembles\ncomprising multiple trajectories in the quark mass plane including physical\npion (and kaon) masses, large volumes, and, most importantly, five different\nlattice spacings down to $a=0.039\\,\\mathrm{fm}$. This allows us to perform a\ncontrolled extrapolation to the continuum and infinite volume limits by a\nsimultaneous fit to all available data. We demonstrate that the formerly\nobserved violation of flavor symmetry breaking constraints can, indeed, be\nattributed to discretization effects that vanish in the continuum limit.",
        "positive": "Topological properties of full QCD at the phase transition: We investigate the topological properties of the QCD vacuum with 4 flavours\nof dynamical staggered fermions at finite temperature. To calculate the\ntopological susceptibility we use the field-theoretical method. As in the\nquenched case, a sharp drop is observed for the topological susceptibility\nacross the phase transition."
    },
    {
        "anchor": "Spectral functions and dynamic critical behavior of relativistic $Z_2$\n  theories: We investigate the dynamic critical behaviour of a relativistic scalar field\ntheory with $Z_2$ symmetry by calculating spectral functions of the order\nparameter at zero and non-vanishing momenta from first-principles\nclassical-statistical lattice simulations in real-time. We find that at\ntemperatures above the critical point $(T > T_c)$, the spectral functions are\nwell described by relativistic quasi-particle peaks. Close to the transition\ntemperature $(T \\sim T_c)$, we observe strong infrared contributions building\nup. In the ordered phase at low temperatures $(T < T_c)$, in addition to the\nquasi-particle peak, we observe a soft mode with a dispersion relation\nindicative of collective excitations. Investigating the spectral functions\nclose to $T_c$, we demonstrate that the behavior in the vicinity of the\ncritical point is controlled by dynamic scaling functions and the dynamic\ncritical exponent $z$, which we determine from our simulations. By considering\nthe equations of motion for a closed system and a system coupled to a heat\nbath, we extract the dynamic critical behavior for two different dynamic\nuniversality classes (Models A & C) in two and three spatial dimensions.",
        "positive": "Beyond complex Langevin equations I: two simple examples: By introducing a second complex variable, the integral relation between a\ncomplex density and the corresponding positive distribution is derived.\nTogether with the positivity and normalizability conditions, this sum rule\nallows to construct explicitly equivalent pairs of distributions in simple\ncases discussed here. In particular the well known solution for a complex\ngaussian distribution is generalized to an arbitrary complex inverse dispersion\nparameter. This opens a possibility of positive representation of Feynman path\nintegrals directly in the Minkowski time."
    },
    {
        "anchor": "Hadron correlators with improved fermions: We investigate point-to-point correlation functions for various mesonic and\nbaryonic channels using the ${\\cal O}(a)$-improved Wilson action due to\nSheikholeslami and Wohlert. We consider propagators to both time slices 0 and\n1. We find that discretisation effects are more pronounced than those reported\nwith unimproved Wilson fermions, but that the same procedure for removing\nfinite size effects is successful. Extrapolating to the chiral limit, we see\nthe notable features predicted phenomenologically: the ratio of interacting to\nfree correlators in the vector channel is roughly constant to about 1 fm, while\nin the pseudoscalar channel the ratio increases markedly due to the strong\nbinding.",
        "positive": "Bayesian inference of real-time dynamics from lattice QCD: The computation of dynamical properties of nuclear matter, ranging from\nparton distribution functions of nucleons and nuclei to transport properties in\nthe quark-gluon plasma, constitutes a central goal of modern theoretical\nphysics. This real-time physics often defies a perturbative treatment and the\nmost successful strategy so far is to deploy lattice QCD simulations. These\nnumerical computations are based on Monte-Carlo sampling and formulated in an\nartificial Euclidean time. Real-time physics is most conveniently formulated in\nterms of spectral functions, which are hidden in lattice QCD behind an\nill-posed inverse problem. I will discuss the current methods state-of-the art\nin the extraction of spectral functions from lattice QCD simulations, based on\nBayesian inference and emphasize the importance of prior domain knowledge,\nvital to regularizing the otherwise ill-posed extraction task. With Bayesian\ninference allowing us to make explicit the uncertainty in both observations and\nin our prior knowledge, a systematic estimation of the total uncertainties in\nthe extracted spectral functions is nowadays possible. Two implementations of\nthe Bayesian Reconstruction (BR) method for spectral function extraction, one\nfor MAP point estimates and one based on an open access Monte-Carlo sampler are\nprovided.I will briefly touch on the use of machine learning for spectral\nfunction reconstruction and discuss some new insight it has brought to the\nBayesian community."
    },
    {
        "anchor": "Locality and Scaling of Quenched Overlap Fermions: The overlap fermion offers the tremendous advantage of exact chiral symmetry\non the lattice, but is numerically intensive. This can be made affordable while\nstill providing large lattice volumes, by using coarse lattice spacing, given\nthat good scaling and localization properties are established. Here, using\noverlap fermions on quenched Iwasaki gauge configurations, we demonstrate\ndirectly that the overlap Dirac operator's range is comfortably small in\nlattice units for each of the lattice spacings 0.20 fm, 0.17 fm, and 0.13 fm\n(and scales to zero in physical units in the continuum limit). In particular,\nour direct results contradict recent speculation that an inverse lattice\nspacing of $1 {\\rm GeV}$ is too low to have satisfactory localization.\nFurthermore, hadronic masses (available on the two coarser lattices) scale very\nwell.",
        "positive": "Gauge theory of things alive and universal dynamics: Positing complex adaptive systems made of agents with relations between them\nthat can be composed, it follows that they can be described by gauge theories\nsimilar to elementary particle theory and general relativity. By definition, a\nuniversal dynamics is able to determine the time development of any such system\nwithout need for further specification. The possibilities are limited, but one\nof them - reproduction fork dynamics - describes DNA replication and is the\nbasis of biological life on earth. It is a universal copy machine and a\nrenormalization group fixed point. A universal equation of motion in continuous\ntime is also presented."
    },
    {
        "anchor": "The spectrum of an SU(3) gauge theory with a fundamental Higgs field: In gauge theories, the physical, experimentally observable spectrum consists\nonly of gauge-invariant states. This spectrum can be different from the\nelementary spectrum even at weak coupling and in the presence of the\nBrout-Englert-Higgs effect. We demonstrate this for an SU(3) gauge theory with\na single fundamental Higgs, a toy theory for grand-unified theories. The\nmanifestly gauge-invariant approach of lattice gauge theory is used to\ndetermine the spectrum in four different channels. It is found to be\nqualitatively different from the elementary one, and especially from the one\npredicted by standard perturbation theory. The result can be understood in\nterms of the Froehlich-Morchio-Strocchi mechanism. In fact, we find that\nanalytic methods based on this mechanism, a gauge-invariant extension of\nperturbation theory, correctly determines the spectrum, and gives already at\nleading order a reasonably good quantitative description. Together with\nprevious results this supports that this approach is the analytic method of\nchoice for theories with a Brout-Englert-Higgs effect.",
        "positive": "Heavy quarks at finite temperature: New incarnations of heavy-ion collision experiments are turning our attention\nto hard processes and a more fine-grained resolution of the QGP. In this\nendeavor quarkonia or open heavy flavors turn out to be versatile probes, which\nare usually described through models based on perturbative QCD, AdS, and\neffective field theories. The lattice provides nonperturbative input and\nconstraints to such models.\\newline In-medium bottomonia, the complex static\nquark-antiquark potential, and the heavy-quark momentum diffusion coefficient\nare key quantities where lattice gauge theory has recently achieved significant\nprogress with impact for heavy-ion phenomenology. We review these lattice\nresults, relate them to phenomenological applications, and close with an\noutlook."
    },
    {
        "anchor": "Form factors of the $D \\to \u03c0$ and $D \\to K$ semileptonic decays with\n  $N_f = 2$ twisted mass lattice QCD: We present lattice results for the vector and scalar form factors of the\nsemileptonic decays D -> \\pi \\ell \\nu_ell and D -> K \\ell \\nu_\\ell in the\nphysical range of values of squared four momentum transfer q^2, obtained with\nN_f=2 maximally twisted Wilson fermions simulated at three different lattice\nspacings (a ~ 0.102 fm, 0.086 fm, 0.068 fm) with pion masses as light as 270\nMeV and m_\\pi L \\gtrsim 4. The form factors are extracted using a double ratios\nstrategy, which allows a good statistical accuracy and is independent of the\nvector current renormalization constant. The chiral/continuum extrapolation is\nperformed through a simultaneous fit in the three variables (m_\\pi, q^2, a)\nusing HMChPT formulae with additional O(a^2) terms that parametrically account\nfor the lattice spacing dependence. Our results are in very good agreement with\nthe experimental data in the full q^2 range for both D -> \\pi \\ell \\nu_\\ell and\nD -> K \\ell \\nu_\\ell. At zero momentum transfer we obtain f^{D->pi}(0) =\n0.65(6)_{stat}(6)_{syst} and f^{D->K}(0) = 0.76(5)_{stat}(5)_{syst}, where the\nsystematic error does not include the effects of quenching the strange and the\ncharm quarks. Our findings are in good agreement with recent lattice\ncalculations at N_f = 2+1.",
        "positive": "Lattice QCD at Non-Zero Temperature: This is a review of selected recent developments in finite-temperature\nlattice QCD. The focus is on the properties of the chiral crossover region,\ndeconfinement and fluctuations of conserved charges, the equation of state,\nproperties of heavy quarkonia and reconstruction of spectral functions."
    },
    {
        "anchor": "Density Induced Phase Transitions in the Schwinger Model: A Study with\n  Matrix Product States: We numerically study the zero temperature phase structure of the multiflavor\nSchwinger model at nonzero chemical potential. Using matrix product states, we\nreproduce analytical results for the phase structure for two flavors in the\nmassless case and extend the computation to the massive case, where no\nanalytical predictions are available. Our calculations allow us to locate phase\ntransitions in the mass-chemical potential plane with great precision and\nprovide a concrete example of tensor networks overcoming the sign problem in a\nlattice gauge theory calculation.",
        "positive": "Plasmon mass scale in two dimensional classical nonequilibrium gauge\n  theory: We study the plasmon mass scale in weakly coupled strongly interacting\nnonabelian gauge theory in a two dimensional configuration that mimics the\nboost invariant initial color fields in a heavy ion collision. We numerically\nmeasure the plasmon mass scale using three different methods: a Hard Thermal\nLoop (HTL) expression involving the quasiparticle spectrum constructed from\nCoulomb gauge field correlators, an effective dispersion relation and the\nmeasurement of oscillations between electric and magnetic energies after\nintroducing a spatially uniform perturbation to the electric field. We find\nthat the hard thermal loop expression and the uniform electric field\nmeasurement are in rough agreement. The effective dispersion relation agrees\nwith other methods within a factor of two. We also study the dependence on time\nand occupation number, observing similar trends as in three spatial dimensions,\nwhere a power law dependence sets in after an occupation number dependent\ntransient time. We observe a decrease of the plasmon mass squared as\n$t^{\\frac{-1}{3}}$ at late times."
    },
    {
        "anchor": "Radiative improvement of the lattice NRQCD action using the background\n  field method and application to the hyperfine splitting of quarkonium states: We present the first application of the background field method to\nNon-Relativistic QCD (NRQCD) on the lattice in order to determine the one-loop\nradiative corrections to the coefficients of the NRQCD action in a manifestly\ngauge-covariant manner. The coefficient of the $\\sigma\\cdot B$ term in the\nNRQCD action is computed at the one-loop level; the resulting shift of the\nhyperfine splitting of bottomonium is found to bring the lattice predictions in\nline with experiment.",
        "positive": "Comparing Different Improvement Programs for the N-Vector Model: We discuss the connection between various types of improved actions in the\ncontext of the two-dimensional sigma-model. We also discuss spectrum-improved\nactions showing that these actions do not have any improved behaviour. An\nO(a^2) on-shell improved action with all couplings defined on a plaquette and\nsatisfying reflection positivity is also explicitly constructed."
    },
    {
        "anchor": "Leading-order hadronic contributions to $g_\u03bc-2$: We present preliminary lattice results for the leading-order hadronic\ncontribution to the muon anomalous magnetic moment, calculated with HEX-smeared\nclover fermions. In our calculation we include 2+1-flavor ensembles with pions\nat the physical mass.",
        "positive": "$\u03c0-\u03c0$ scattering, QED and finite-volume quantization: Using the Coulomb gauge formulation of QED we present a lattice QCD procedure\nto calculate the $\\pi^+\\pi^+$ scattering phase shift including the effects of\nthe Coulomb potential which appears in this formulation. The approach described\nhere incorporates the effects of relativity and avoids finite-volume\ncorrections that vanish as a power of the volume in which the lattice\ncalculation is performed. This is the first step in developing a complete\nlattice QCD calculation of the electromagnetic and isospin-breaking light-quark\nmass contributions to $\\varepsilon'$, the parameter describing direct CP\nviolating effects in $K_L\\to\\pi\\pi$ decay."
    },
    {
        "anchor": "Bootstrapping Lattice Vacua: This paper demonstrates the application of semidefinite programming to\nlattice field theories, showcasing spin chains and lattice scalar field theory.\nRequiring expectation values of manifestly positive semi-definite operators to\nbe non-negative results in a lower bound on the ground-state energy of any\nquantum mechanical system, which can be made arbitrarily tight for systems\ndescribed by finite-dimensional Hilbert spaces. Such bounds can be obtained\ndirectly in the infinite-volume limit. The process of optimizing these lower\nbounds also yields estimates for a chosen set of expectation values in the\nground state.",
        "positive": "Lattice QCD ensembles with four flavors of highly improved staggered\n  quarks: We present results from our simulations of quantum chromodynamics (QCD) with\nfour flavors of quarks: u, d, s, and c. These simulations are performed with a\none-loop Symanzik improved gauge action, and the highly improved staggered\nquark (HISQ) action. We are generating gauge configurations with four values of\nthe lattice spacing ranging from 0.06 fm to 0.15 fm, and three values of the\nlight quark mass, including the value for which the Goldstone pion mass is\nequal to the physical pion mass. We discuss simulation algorithms, scale\nsetting, taste symmetry breaking, and the autocorrelations of various\nquantities. We also present results for the topological susceptibility which\ndemonstrate the improvement of the HISQ configurations relative to those\ngenerated earlier with the asqtad improved staggered action."
    },
    {
        "anchor": "Sharing lattices throughout the world: an ILDG status report: The international lattice data grid, a system for sharing gauge configuration\nfiles throughout the world, is operational for the most part. I give a status\nreport, give some pointers on accessing lattice files, and highlight some of\nthe available gauge configurations.",
        "positive": "Exploring autocorrelations in two-flavour Wilson Lattice QCD using\n  DD-HMC algorithm: We perform an extensive study of autocorrelation of several observables in\nlattice QCD with two degenerate flavours of naive Wilson fermions and\nunimproved Wilson gauge action using DD-HMC algorithm. We show that (1) at a\ngiven lattice spacing, autocorrelation of topological susceptibility decreases\nwith decreasing quark mass and autocorrelations of plaquette and Wilson loop do\nnot increase with decreasing quark mass, (2) autocorrelation of topological\nsusceptibility substantially increases with decreasing lattice spacing but\nautocorrelation of topological charge density correlator shows only mild\nincrease and (3) increasing the size and the smearing level increase the\nautocorrelation of Wilson loop."
    },
    {
        "anchor": "New methods for B meson decay constants and form factors from lattice\n  NRQCD: We determine the normalisation of scalar and pseudoscalar current operators\nmade from non-relativistic $b$ quarks and Highly Improved Staggered light\nquarks in lattice Quantum Chromodynamics (QCD) through $\\mathcal{O}(\\alpha_s)$\nand $\\Lambda_{\\text{QCD}}/m_b$. We use matrix elements of these operators to\nextract $B$ meson decay constants and form factors, then compare to those\nobtained using the standard vector and axial-vector operators. This provides a\ntest of systematic errors in the lattice QCD determination of the $B$ meson\ndecay constants and form factors. We provide a new value for the $B$ and $B_s$\nmeson decay constants from lattice QCD calculations on ensembles that include\n$u$, $d$, $s$ and $c$ quarks in the sea and those which have the $u/d$ quark\nmass going down to its physical value. Our results are $f_B=0.196(6)$ GeV,\n$f_{B_s}=0.236(7)$ GeV and $f_{B_s}/f_B =1.207(7)$, agreeing well with earlier\nresults using the temporal axial current. By combining with these previous\nresults, we provide updated values of $f_B=0.190(4)$ GeV, $f_{B_s}=0.229(5)$\nGeV and $f_{B_s}/f_B = 1.206(5)$.",
        "positive": "Gluon Propagator on Coarse Lattices in Laplacian Gauges: The Laplacian gauge is a nonperturbative gauge fixing that reduces to Landau\ngauge in the asymptotic limit. Like Landau gauge, it respects Lorentz\ninvariance, but it is free of Gribov copies; the gauge fixing is unambiguous.\nIn this paper we study the infrared behavior of the lattice gluon propagator in\nLaplacian gauge by using a variety of lattices with spacings from $a = 0.125$\nto 0.35 fm, to explore finite volume and discretization effects. Three\ndifferent implementations of the Laplacian gauge are defined and compared. The\nLaplacian gauge propagator has already been claimed to be insensitive to finite\nvolume effects and this is tested on lattices with large volumes."
    },
    {
        "anchor": "Freeze-out parameters from continuum extrapolated lattice data: We present continuum extrapolated lattice results for the higher order\nfluctuations of conserved charges in high temperature Quantum Chromodynamics.\nThrough the matching of the grand canonical ensemble on the lattice to the net\ncharge and net baryon distribution realized in heavy ion experiments the\ntemperature and the chemical potential may be estimated at the time of chemical\nfreeze-out",
        "positive": "Axial U(1) symmetry, topology, and Dirac spectra at high temperature in\n  $N_f=2$ lattice QCD: Using lattice QCD simulations with $N_f = 2$ dynamical fermions, we study the\naxial $U(1)$ symmetry, topological charge, and Dirac eigenvalue spectra in the\nhigh-temperature phase in which the chiral symmetry is restored. Our gauge\nensembles are generated with M\\\"obius domain-wall fermions, but the\nmeasurements such as susceptibilities are reweighted to those for the overlap\nfermions by using overlap/domain-wall reweighting technique. We find that the\n$U(1)_A$ and topological susceptibilities are strongly suppressed in the small\nquark mass region, which is related to the reduction of chiral-zero and\nlow-nonzero modes on the Dirac spectra. We also examine their volume\ndependence."
    },
    {
        "anchor": "Lattice study on $\u03c0K $ scattering with moving wall source: The s-wave pion-kaon ($\\pi K$) scattering lengths at zero momentum are\ncalculated in lattice QCD with sufficiently light $u/d$ quarks and strange\nquark at its physical value by the finite size formula. The light quark masses\ncorrespond to $m_\\pi = 0.330 - 0.466$ GeV. In the \"Asqtad\" improved staggered\nfermion formulation, we measure the $\\pi K$ four-point correlators for both\nisospin $I=1/2$ and 3/2 channels, and analyze the lattice simulation data at\nthe next-to-leading order in the continuum three-flavor chiral perturbation\ntheory, which enables us a simultaneous extrapolation of $\\pi K$ scattering\nlengths at physical point. We adopt a technique with the moving wall sources\nwithout gauge fixing to obtain the substantiable accuracy, moreover, for $I =\n1/2$ channel, we employ the variational method to isolate the contamination\nfrom the excited states. Extrapolating to the physical point yields the\nscattering lengths as $m_\\pi a_{3/2} = -0.0505(19)$ and $m_\\pi a_{1/2} =\n0.1827(37)$ for $I=3/2$ and 1/2 channels, respectively. Our simulation results\nfor $\\pi K$ scattering lengths are in agreement with the experimental reports\nand theoretical predictions, and can be comparable with other lattice\nsimulations. These simulations are carried out with MILC $N_f = 2+1$ flavor\ngauge configurations at lattice spacing $a \\approx 0.15$ fm.",
        "positive": "The physics of eight flavours: We study Quantum Chromodynamics with eight flavours by use of lattice\nsimulations and present evidence that the theory still breaks chiral symmetry\nin the zero temperature, continuum limit. This confirms that the lower end of\nthe conformal window of QCD lies above Nf = 8."
    },
    {
        "anchor": "Simplicial Gravity in Dimension Greater than Two: We consider two issues in the DT model of quantum gravity. First, it is shown\nthat the triangulation space for D>3 is dominated by triangulations containing\na single singular (D-3)-simplex composed of vertices with divergent dual\nvolumes. Second we study the ergodicity of current simulation algorithms.\nResults from runs conducted close to the phase transition of the\nfour-dimensional theory are shown. We see no strong indications of ergodicity\nbr eaking in the simulation and our data support recent claims that the\ntransition is most probably first order. Furthermore, we show that the critical\nproperties of the system are determined by the dynamics of remnant singular\nvertices.",
        "positive": "On the mass of the world-sheet `axion' in SU(N) gauge theories in 3+1\n  dimensions: There is numerical evidence that the world sheet action of the confining flux\ntube in D=3+1 SU(N) gauge theories contains a massive excitation with 0-\nquantum numbers whose mass shows some decrease as one goes from SU(3) to SU(5).\nIt has furthermore been shown that this particle is naturally described as\narising from a topological interaction term in the world-sheet action, so that\none can describe it as being `axion'-like. Recently it has been pointed out\nthat if the mass of this `axion' vanishes as N -> oo then it becomes possible\nfor the world sheet theory to be integrable in the planar limit. In this paper\nwe perform lattice calculations of this `axion' mass from SU(2) to SU(12),\nwhich allows us to make a controlled extrapolation to N=oo and so test this\ninteresting possibility. We find that the `axion' does not in fact become\nmassless as N -> oo. So if the theory is to possess planar integrability then\nit must be some other world sheet excitation that becomes massless in the\nplanar limit."
    },
    {
        "anchor": "Topology and $\u03b8$ dependence in finite temperature $G_2$ lattice\n  gauge theory: In this work we study the topological properties of the $G_2$ lattice gauge\ntheory by means of Monte Carlo simulations. We focus on the behaviour of\ntopological quantities across the deconfinement transition and investigate\nobservables related to the $\\theta$ dependence of the free energy. As in\n$SU(N)$ gauge theories, an abrupt change happens at deconfinement and an\ninstanton gas behaviour rapidly sets in for $T>T_c$.",
        "positive": "Topology and Low Lying Fermion Modes: Recent results concerning the relation of topology and low-lying fermion\nmodes are summarized."
    },
    {
        "anchor": "$J/\u03c8$ -nucleon scattering in $P_{c}^{+}$ pentaquarks channel: Two pentaquarks $P_{c}^{+}$ were discovered by LHCb collaboration as peaks in\nthe proton-$J/\\psi$ invariant mass. We perform the lattice QCD study of the\nscattering between $J/\\psi$ meson and nucleon in the channels with\n$J^{P}=\\frac{3}{2}^{+},\\frac{3}{2}^{-}, \\frac{5}{2}^{+}, \\frac{5}{2}^{-}$,\nwhere $P_{c}^{+}$ was discovered. This is the first lattice simulation that\nreaches the energies $4.3-4.5~$GeV where pentaquarks reside. The higher partial\nwaves $L>0$ are also explored for the first time. In this study we consider the\nsingle-channel approximation for scattering of $NJ/\\psi$. Energies and\neigenstates are extracted for the $NJ/\\psi$ system at the zero total momentum\nfor all six irreducible representations of the lattice irreducible\nrepresentation. No significant energy shifts are observed. The number of\neigenstates agrees with the number expected from non-interacting limit for\nscattering. This could possibly indicate that the $P_{c}$ resonances seen in\nexperiment are a consequence of a coupling of the $NJ/\\psi$ channel with other\ntwo-hadron channels.",
        "positive": "Diseases with rooted staggered quarks: Calculations using staggered quarks augmented with a root of the fermion\ndeterminant to reduce doubling give a qualitatively incorrect behavior in the\nsmall quark mass region. Attempts to circumvent this problem for the continuum\nlimit involve an unproven combination of unphysical states, a loss of\nunitarity, and a rather peculiar non-commutation of limits."
    },
    {
        "anchor": "The calculation of nucleon strangeness form factors from N_f=2+1 clover\n  fermion lattice QCD: We study the strangeness electromagnetic form factors of the nucleon from the\nN_f=2+1 clover fermion lattice QCD calculation. The disconnected insertions are\nevaluated using the Z(4) stochastic method, along with unbiased subtractions\nfrom the hopping parameter expansion. In addition to increasing the number of\nZ(4) noises, we find that increasing the number of nucleon sources for each\nconfiguration improves the signal significantly. We obtain G_M^s(0) =\n-0.017(25)(07), where the first error is statistical, and the second is the\nuncertainties in Q^2 and chiral extrapolations. This is consistent with\nexperimental values, and has an order of magnitude smaller error. We also study\nthe strangeness second moment of the partion distribution function of the\nnucleon, <x^2>_{s-\\bar{s}}.",
        "positive": "Lattice Calculations of Heavy Quark Potential at Finite Temperature: We report on the lattice calculations of the heavy quark potential at $T>0$\nin 2+1 flavor QCD at physical quark masses using the Highly Improved Staggered\nQuark discretization. We study in detail the systematic effects in the\ndetermination of the real and imaginary parts of the potential when using the\nmoment method."
    },
    {
        "anchor": "Behaviour of the topological susceptibility in two colour QCD across the\n  finite density transition: The behaviour of the topological susceptibility \\chi in QCD with two colours\nand 8 flavours of quarks is studied at nonzero temperature on the lattice\nacross the finite density transition. It is shown that the signal of \\chi drops\nabruptly at a critical chemical potential \\mu_c, much as it happens at the\nfinite temperature and zero density transition. The Polyakov loop and the\nchiral condensate undergo their transitions at the same critical value \\mu_c.\nAt a value \\mu_s of the chemical potential, called saturation point, which in\nour case satisfies \\mu_s > \\mu_c, Pauli blocking supervenes and consequently\nthe theory becomes quenched.",
        "positive": "Collins-Soper Kernel for TMD Evolution from Lattice QCD: The Collins-Soper kernel relates transverse momentum-dependent parton\ndistribution functions (TMDPDFs) at different energy scales. For small parton\ntransverse momentum $q_T\\sim \\Lambda_\\text{QCD}$, this kernel is\nnon-perturbative and can only be determined with controlled uncertainties\nthrough experiment or first-principles calculations. This work presents the\nfirst exploratory determination of the Collins-Soper kernel using the lattice\nformulation of Quantum Chromodynamics. In a quenched calculation, the $N_f=0$\nkernel is determined at scales in the range 250 MeV $< q_T < 2$ GeV, and an\nanalysis of the remaining systematic uncertainties is undertaken."
    },
    {
        "anchor": "Leptonic decay constants for D-mesons from 3-flavour CLS ensembles: We report on the status of an ongoing effort by the RQCD and ALPHA\nCollaborations, aimed at determining leptonic decay constants of charmed\nmesons. Our analysis is based on large-volume ensembles generated within the\nCLS effort, employing N_f=2+1 non-perturbatively O(a) improved Wilson quarks,\ntree-level Symanzik-improved gauge action and open boundary conditions. The\nensembles cover lattice spacings from a ~ 0.09 fm to a ~ 0.05 fm, with pion\nmasses varied from 420 to 200 MeV. To extrapolate to the physical masses, we\nfollow both the 2m_l+m_s=const. and the m_s=const. lines in parameter space.",
        "positive": "A further extension to the group of Ginsparg-Wilson (overlap) chiral\n  symmetries: As shown by Mandula, the Ginsparg-Wilson lattice realisation of chiral\nsymmetry has a possible ambiguity: there is no unique lattice chiral symmetry,\nbut an infinite group of symmetries with non-commuting generators. The physical\nimplications of this abundance of symmetry remain unclear. In recent work, it\nhas been shown how these chiral symmetries for overlap fermions can be derived\nfrom a renormalisation group blocking in the continuum, transforming the action\nfrom the standard continuum action to an equivalent to the lattice overlap\naction. There is no unique blocking, and different blockings lead to different\nchiral symmetries. The group of symmetries found by Mandula immediately\nfollows. In this way, the excess chiral symmetry on the lattice can be\nexplained in terms of different renormalisation schemes.\n  The previous work suffered from one technical challenge: there is no\ncontinuum analogue of the lattice chiral eigenvectors at eigenvalue $2/a$. As\nthe construction of the overlap operator required a mapping between lattice and\ncontinuum eigenvalues, the lack of a continuum counterpart to the doublers of\nthe zero modes creates an ambiguity in the construction. Although the lattice\nchiral symmetry can still be defined, this leads to difficulties when\nconsidering $\\mathcal{CP}$ symmetry on the lattice. In this work, we\ninvestigate the possibility of resolving this ambiguity by adding a second\nfermion field to the original continuum action used as a basis of the\nrenormalisation group blockings. This second fermion field has a mass of the\norder of the momentum cut-off, to simulate the effects of the fermion doublers.\nWorking through the same renormalisation group procedure to map this action to\nthe lattice overlap action yields additional Ginsparg-Wilson relations\nsatisfied by the overlap operator, and more (non-commuting) lattice chiral\nsymmetries."
    },
    {
        "anchor": "Minimal Doubling Fermion and Hermiticity: We analyze the lattice fermion kinetic term using PT symmetry, R-hermiticity,\nand $\\gamma_{5}$-hermiticity. R-hermiticity is a condition for Hermite action\nand it is related to $\\gamma_{5}$-hermiticity and PT symmetry. Assuming that a\ntranslation-invariant kinetic term with continuum and periodic function does\nnot have PT symmetry, it can have R-hermiticity or $\\gamma_{5}$-hermiticity. We\nprove that a kinetic term with continuum and periodic function that is PT\nsymmetric does not reduce doublers. As a simple example, we analyze the\ntwo-dimensional two-flavor Gross-Neveu model with minimal doubling fermions.\nThe minimal doubling fermions break PT symmetry and R-hermiticity, hence\ncomplex or non-Hermite coupling constants are caused by quantum correction.",
        "positive": "A New Exact Method for Dynamical Fermion Computations with Non-Local\n  Actions: We introduce a new algorithm which we call the {Rational Hybrid Monte Carlo}\nAlgorithm (RHMC). This method uses a rational approximation to the fermionic\nkernel together with a noisy Kennedy-Kuti acceptance step to give an efficient\nalgorithm with no molecular dynamics integration step-size errors."
    },
    {
        "anchor": "Thermal dilepton rate and electrical conductivity: An analysis of vector\n  current correlation functions in quenched lattice QCD: We calculate the vector current correlation function for light valence quarks\nin the deconfined phase of QCD. The calculations have been performed in\nquenched lattice QCD at T=1.45 Tc for four values of the lattice cut-off on\nlattices up to size 128^3x48. This allows to perform a continuum extrapolation\nof the correlation function in the Euclidean time interval tau*T -in [0.2,\n0.5], which extends to the largest temporal separations possible at finite\ntemperature, to better than 1% accuracy. In this interval, at the value of the\ntemperature investigated, we find that the vector correlation function never\ndeviates from the free correlator for massless quarks by more than 9%. We also\ndetermine the first two non-vanishing thermal moments of the vector meson\nspectral function. The second thermal moment deviates by less than 7% from the\nfree value. With these constraints, we then proceed to extract information on\nthe spectral representation of the vector correlator and discuss resulting\nconsequences for the electrical conductivity and the thermal dilepton rate in\nthe plasma phase.",
        "positive": "On the fractal structure of two-dimensional quantum gravity: We provide evidence that the Hausdorff dimension is 4 and the spectral\ndimension is 2 for two-dimensional quantum gravity coupled the matter with a\ncentral charge $c \\leq 1$. For $c > 1$ the Hausdorff dimension and the spectral\ndimension monotonously decreases to 2 and 1, respectively."
    },
    {
        "anchor": "String breaking: We numerically investigate the transition of the static quark-antiquark\nstring into a static-light meson-antimeson system. Improving noise reduction\ntechniques, we are able to resolve the signature of string breaking dynamics\nfor Nf=2 lattice QCD at zero temperature. We discuss the lattice techniques\nused and present results on energy levels and mixing angle of the static\ntwo-state system. We visualize the action density distribution in the region of\nstring breaking as a function of the static colour source-antisource\nseparation. The results can be related to properties of quarkonium systems.",
        "positive": "Monte Carlo Simulation Calculation of Critical Coupling Constant for\n  Continuum \u03c6^4_2: We perform a Monte Carlo simulation calculation of the critical coupling\nconstant for the continuum {\\lambda \\over 4} \\phi^4_2 theory. The critical\ncoupling constant we obtain is [{\\lambda \\over \\mu^2}]_crit=10.24(3)."
    },
    {
        "anchor": "Prospects for $\u03b3^\\star \u03b3^\\star \\to \u03c0\u03c0$ via lattice QCD: The $\\gamma^\\star \\gamma^\\star \\to \\pi \\pi$ scattering amplitude plays a key\nrole in a wide range of phenomena, including understanding the inner structure\nof scalar resonances as well as constraining the hadronic contributions to the\nanomalous magnetic moment of the muon. In this work, we explain how the\ninfinite-volume Minkowski amplitude can be constrained from finite-volume\nEuclidean correlation functions. The relationship between the finite-volume\nEuclidean correlation functions and the desired amplitude holds up to energies\nwhere $3\\pi$ states can go on shell, and is exact up to exponentially small\ncorrections that scale like $\\mathcal{O}(e^{-m_\\pi L})$, where $L$ is the\nspatial extent of the cubic volume and $m_\\pi$ is the pion mass. In order to\nimplement this formalism and remove all power-law finite volume errors, it is\nnecessary to first obtain $\\pi \\pi \\to \\pi\\pi$, $\\pi \\gamma^\\star \\to \\pi$,\n$\\gamma^\\star \\to\\pi\\pi$, and $\\pi\\pi\\gamma^\\star \\to\\pi\\pi$ amplitudes; all of\nwhich can be determined via lattice quantum chromodynamic calculations.",
        "positive": "Ginsparg-Wilson Games: I implement a set of tricks for constructing lattice fermion actions which\napproximately realize the Ginsparg-Wilson relation, with very promising results\nfrom simulations."
    },
    {
        "anchor": "Analytical study of fermion determinant and chiral condensate behavior\n  at finite temperatures in toy model approximation: Fermion determinant is computed analytically on extremely large lattices $%\nN_\\tau \\to \\infty $ in the toy model approximation in which action is truncated\nso that in the Hamiltonian limit of $a_\\tau \\to 0$ all terms of order $a_\\tau\n/a_\\sigma $ are discarded$.$ Chiral condensate is studied in the area of small\n($m<<T$) quark masses.",
        "positive": "Numerical study of the Yang-Mills vacuum wavefunctional in D=3+1\n  dimensions: Ratios of the true Yang-Mills vacuum wavefunctional, evaluated on any two\nfield configurations out of a finite set of configurations, can be obtained\nfrom lattice Monte Carlo simulations. The method was applied some years ago to\ntest various proposals for the vacuum wavefunctional in 2+1 dimensions. In this\narticle we use the same method to test our own proposal for the Yang-Mills\nground state in 3+1 dimensions. This state has the property of \"dimensional\nreduction\" at large scales, meaning that the (squared) vacuum state, evaluated\non long-wavelength, large scale fluctuations, has the form of the Boltzmann\nweight for Yang-Mills theory in D=3 Euclidean dimensions. Our numerical results\nsupport this conjectured behavior. We also investigate the form of the ground\nstate evaluated on shorter wavelength configurations."
    },
    {
        "anchor": "Low-energy Scattering and Effective Interactions of Two Baryons at\n  $m_\u03c0\\sim 450$ MeV from Lattice Quantum Chromodynamics: The interactions between two octet baryons are studied at low energies using\nlattice QCD (LQCD) with larger-than-physical quark masses corresponding to a\npion mass of $m_{\\pi}\\sim 450$ MeV and a kaon mass of $m_{K}\\sim 596$ MeV. The\ntwo-baryon systems that are analyzed range from strangeness $S=0$ to $S=-4$ and\ninclude the spin-singlet and triplet $NN$, $\\Sigma N$ ($I=3/2$), and $\\Xi\\Xi$\nstates, the spin-singlet $\\Sigma\\Sigma$ ($I=2$) and $\\Xi\\Sigma$ ($I=3/2$)\nstates, and the spin-triplet $\\Xi N$ ($I=0$) state. The $s$-wave scattering\nphase shifts, low-energy scattering parameters, and binding energies when\napplicable, are extracted using L\\\"uscher's formalism. While the results are\nconsistent with most of the systems being bound at this pion mass, the\ninteractions in the spin-triplet $\\Sigma N$ and $\\Xi\\Xi$ channels are found to\nbe repulsive and do not support bound states. Using results from previous\nstudies at a larger pion mass, an extrapolation of the binding energies to the\nphysical point is performed and is compared with experimental values and\nphenomenological predictions. The low-energy coefficients in pionless EFT\nrelevant for two-baryon interactions, including those responsible for $SU(3)$\nflavor-symmetry breaking, are constrained. The $SU(3)$ symmetry is observed to\nhold approximately at the chosen values of the quark masses, as well as the\n$SU(6)$ spin-flavor symmetry, predicted at large $N_c$. A remnant of an\naccidental $SU(16)$ symmetry found previously at a larger pion mass is further\nobserved. The $SU(6)$-symmetric EFT constrained by these LQCD calculations is\nused to make predictions for two-baryon systems for which the low-energy\nscattering parameters could not be determined with LQCD directly in this study,\nand to constrain the coefficients of all leading $SU(3)$ flavor-symmetric\ninteractions, demonstrating the predictive power of two-baryon EFTs matched to\nLQCD.",
        "positive": "The S, U and \u0394\u03c1parameters in the Zaragoza proposal for lattice\n  chiral gauge fermions: Using the Zaragoza proposal for lattice chiral gauge fermions, the S, U and\n\\Delta\\rho parameters have been calculated at one loop. It is shown that the\ncontinuum values for these quantities can be reproduced without requiring\nexplicit fine tuning of counterterms. Furthermore, fermion fields doubling is\nnot necessary. To the best of our knowledge, the Zaragoza proposal is the only\nscheme which has these properties. A necessary (although not sufficient)\nsymmetry is found to support the calculations. Previous results for some of\nthese parameters in other lattice chiral regularizations are revisited in the\nlight of this symmetry."
    },
    {
        "anchor": "Continuum limit of susceptibility from strong coupling expansion: Two\n  dimensional non-linear O(N) sigma model at N>= 3: Based on the strong coupling expansion, we reinvestigate the scaling behavior\nof the susceptibility chi of two-dimensional O(N) sigma model on the square\nlattice by the use of Pade-Borel approximants. To exploit the Borel transform,\nwe express the bare coupling g in series expansion in chi. At large N,\nPade-Borel approximants exhibit the scaling behavior at the four-loop level.\nThen, the estimation of the non-perturbative constant associated with the\nsusceptibility is performed for N>=3 and the results are compared with the\navailable theoretical results and Monte Carlo data.",
        "positive": "Oscillating propagators in heavy-dense QCD: Using Monte Carlo simulations and extended mean field theory calculations we\nshow that the $3$-dimensional $Z_3$ spin model with complex external fields has\nnon-monotonic spatial correlators in some regions of its parameter space. This\nmodel serves as a proxy for heavy-dense QCD in $(3+1)$ dimensions.\nNon-monotonic spatial correlators are intrinsically related to a complex mass\nspectrum and a liquid-like (or crystalline) behavior. A liquid phase could have\nimplications for heavy-ion experiments, where it could leave detectable signals\nin the spatial correlations of baryons."
    },
    {
        "anchor": "Testing mixed action approaches to meson spectroscopy with twisted mass\n  sea quarks: We explore and compare three mixed action setups with Wilson twisted mass sea\nquarks and different valence quark actions: (1) Wilson twisted mass, (2) Wilson\ntwisted mass + clover and (3) Wilson + clover. Our main goal is to reduce\nlattice discretization errors in mesonic spectral quantities, in particular to\nreduce twisted mass parity and isospin breaking.",
        "positive": "More on the continuum limit of gauge-fixed compact U(1) lattice gauge\n  theory: We have verified various proposals that were suggested in our last paper\nconcerning the continuum limit of a compact formulation of the lattice U(1)\npure gauge theory in 4 dimensions using a nonperturbative gauge-fixed\nregularization. Our study reveals that most of the speculations are largely\ncorrect. We find clear evidence of a continuous phase transition in the pure\ngauge theory at \"arbitrarily\" large couplings. When probed with quenched\nstaggered fermions with U(1) charge, the theory clearly has a chiral transition\nfor large gauge couplings whose intersection with the phase transition in the\npure gauge theory continues to be a promising area for nonperturbative physics.\nWe probe the nature of the continuous phase transition by looking at gauge\nfield propagators in the momentum space and locate the region on the critical\nmanifold where free photons can be recovered."
    },
    {
        "anchor": "Heavy quark free energies for three quark systems at finite temperature: We study the free energy of static three quark systems in singlet, octet,\ndecuplet and average color channels in the quenched approximation and in\n2-flavor QCD at finite temperature. We show that in the high temperature phase\nsinglet and decuplet free energies of three quark systems are well described by\nthe sum of the free energies of three diquark systems plus self energy\ncontributions of the three quarks. In the confining low temperature phase we\nfind evidence for a Y-shaped flux tube in SU(3) pure gauge theory, which is\nless evident in 2-flavor QCD due to the onset of string breaking. We also\ncompare the short distance behavior of octet and decuplet free energies to the\nfree energies of single static quarks in the corresponding color\nrepresentations.",
        "positive": "Vector and Axial Currents in Wilson Chiral Perturbation Theory: We reconsider the construction of the vector and axial-vector currents in\nWilson Chiral Perturbation Theory (WChPT), the low-energy effective theory for\nlattice QCD with Wilson fermions. We discuss in detail the finite\nrenormalization of the currents that has to be taken into account in order to\nproperly match the currents. We explicitly show that imposing the chiral Ward\nidentities on the currents does, in general, affect the axial-vector current at\nO(a). As an application of our results we compute the pion decay constant to\none loop in the two flavor theory. Our result differs from previously published\nones."
    },
    {
        "anchor": "One loop calculation of the renormalised anisotropy for improved\n  anisotropic gluon actions on a lattice: Using the infrared dispersion relation of the on shell gluon, we calculate\nthe renormalisation of the the anisotropy to one loop in perturbation theory\nfor lattice Yang-Mills theories, including the Wilson action and actions with\nSymanzik and/or tadpole improvement. Using twisted boundary conditions as a\ngauge invariant infrared regulator, we show for an SU(3) gauge group in D=3+1\ndimensions that the one loop anisotropy is accurate to O(3%) for a range of g^2\nand chi covering current simulations. In doing so we also present Feynman rules\nfor SU(N) gauge groups with generic anisotropy structure (including `3+1' and\n`2+2' cases).",
        "positive": "The string tension for Large N gauge theory from smeared Wilson loops: Using smeared Creutz ratios we extract the string tension for SU(N) pure\ngauge theory and $N$=3,4,5,6,8. We employ these results to extrapolate to large\nN. The same methodology is applied to the single-site Twisted Eguchi Kawai\nmodel. The corresponding string tension matches perfectly within errors with\nthe extrapolated one, providing strong evidence in favour of the twisted\nreduction framework. Interesting results are also obtained on the behaviour of\nCreutz ratios for large sizes."
    },
    {
        "anchor": "The spatial string tension and dimensional reduction in QCD: The spatial string tension for 3+1 dimensional QCD at finite temperature is\nmeasured. The gauge configurations we re generated with two light and one\nheavier strange quark on lattices of size $16^3 4$ and $24^3 6$. This spatial\nstring tension is compared with the string tension of the 3 dimensional pure\ngauge theory together with the temperature dependent 2-loop running coupling.\nFurther comparison is made with predictions from dimensionally reduced\neffective theories.",
        "positive": "Speeding up the HMC: QCD with Clover-Improved Wilson Fermions: We apply a recent proposal to speed up the Hybrid-Monte-Carlo simulation of\nsystems with dynamical fermions to two flavor QCD with clover-improvement. For\nour smallest quark masses we see a speed-up of more than a factor of two\ncompared with the standard algorithm."
    },
    {
        "anchor": "Clebsch-Gordan Construction of Lattice Interpolating Fields for Excited\n  Baryons: Large sets of baryon interpolating field operators are developed for use in\nlattice QCD studies of baryons with zero momentum. Operators are classified\naccording to the double-valued irreducible representations of the octahedral\ngroup. At first, three-quark smeared, local operators are constructed for each\nisospin and strangeness and they are classified according to their symmetry\nwith respect to exchange of Dirac indices. Nonlocal baryon operators are\nformulated in a second step as direct products of the spinor structures of\nsmeared, local operators together with gauge-covariant lattice displacements of\none or more of the smeared quark fields. Linear combinations of direct products\nof spinorial and spatial irreducible representations are then formed with\nappropriate Clebsch-Gordan coefficients of the octahedral group. The\nconstruction attempts to maintain maximal overlap with the continuum SU(2)\ngroup in order to provide a physically interpretable basis. Nonlocal operators\nprovide direct couplings to states that have nonzero orbital angular momentum.",
        "positive": "Challenges in Hadronic Form Factor Calculations: There is an extensive history of form factor calculations on the lattice,\nprimarily with ground states for both initial and final states. However, there\nhave never been any radially excited transition form factor calculations.\nFurthermore, the lattice faces difficulty in extracting signal from noise at\nlarge transfer momenta ($Q^2$). These measurements could give important\ntheoretical input to experiments, such as those of JLab's 12 GeV program and\nstudies of deformation of the nucleon. In this work, I will present a simple\ntechnique to resolve both of these difficulties and present results from\nanisotropic configurations showing improved signals for excited-state\nquantities. It should also be possible to apply this technique to isotropic\nlattices for calculating large-$Q^2$ form factors."
    },
    {
        "anchor": "Spectroscopy and Decay Constants from Nonperturbative HQET at Order 1/m: We carry out a thorough analysis with the GEVP method to obtain ground-state\nand first-excited-state masses and decay constants of bottom-strange\n(pseudo-scalar and vector) mesons. This computation is done for quenched,\nnonperturbatively renormalized HQET, including order $1/m_b$ terms. The\ncontinuum limit is obtained using three lattice spacings and two static\nactions.",
        "positive": "Precision lattice test of the gauge/gravity duality at large-$N$: We pioneer a systematic, large-scale lattice simulation of D0-brane quantum\nmechanics. The large-$N$ and continuum limits of the gauge theory are taken for\nthe first time at various temperatures $0.4 \\leq T \\leq 1.0$. As a way to\ndirectly test the gauge/gravity duality conjecture we compute the internal\nenergy of the black hole directly from the gauge theory and reproduce the\ncoefficient of the supergravity result $E/N^2=7.41T^{14/5}$. This is the first\nconfirmation of the supergravity prediction for the internal energy of a black\nhole at finite temperature coming directly from the dual gauge theory. We also\nconstrain stringy corrections to the internal energy."
    },
    {
        "anchor": "Glueball Spectrum and Matrix Elements on Anisotropic Lattices: The glueball-to-vacuum matrix elements of local gluonic operators in scalar,\ntensor, and pseudoscalar channels are investigated numerically on several\nanisotropic lattices with the spatial lattice spacing ranging from 0.1fm -\n0.2fm. These matrix elements are needed to predict the glueball branching\nratios in $J/\\psi$ radiative decays which will help identify the glueball\nstates in experiments. Two types of improved local gluonic operators are\nconstructed for a self-consistent check and the finite volume effects are\nstudied. We find that lattice spacing dependence of our results is very weak\nand the continuum limits are reliably extrapolated, as a result of improvement\nof the lattice gauge action and local operators. We also give updated glueball\nmasses with various quantum numbers.",
        "positive": "Chiral spin symmetry and hot/dense QCD: Above the chiral symmetry restoration crossover around T_{ch} ~ 155 MeV a new\nregime arises in QCD, a stringy fluid, which is characterized by an approximate\nchiral spin symmetry of the thermal partition function. This symmetry is not a\nsymmetry of the Dirac Lagrangian and is a symmetry of the electric part of the\nQCD Lagrangian. In this regime the medium consists of the chirally symmetric\nand approximately chiral spin symmetric hadrons that are made of the chirally\nsymmetric quarks connected into the color singlet compounds by a confining\nchromoelectric field. This regime is evidenced by the approximate chiral spin\nsymmetry of the spatial and temporal correlators and by the breakdown of the\nthermal perturbation theory at the crossover between the partonic (the\nquark-gluon plasma) and stringy fluid regimes at ~ 3 T_{ch}. The chiral spin\nsymmetry smoothly disappears above ~ 3T_{ch} which means that the\nchromoelectric confining interaction gets screened. A direct evidence that the\nstringy fluid medium consists of densely packed hadrons is the pion spectral\nfunction that shows a distinct pion state and its first radial excitation above\nT_{ch}. Another direct evidence of the hadron degrees of freedom in the stringy\nfluid is the bottomonium spectrum with the 1S,2S,3S and 1P,2P radial and\norbital excitations that become broad with temperature. The hadrons between\nT_{ch} and ~ 3 T_{ch} in the stringy fluid interact strongly which makes the\nstringy fluid more a liquid rather than a gas. We discuss how this chiral spin\nsymmetric regime extends into the finite chemical potentials domain and present\na qualitative sketch of the QCD phase diagram."
    },
    {
        "anchor": "Critical Behaviour in Statistical QCD: We survey the critical behaviour of strongly interacting matter, as\ndetermined in finite temperature lattice QCD.",
        "positive": "Evidence for diquarks in lattice QCD: Diquarks may play an important role in hadron spectroscopy, baryon decays and\ncolor superconductivity. We investigate the existence of diquark correlations\nin lattice QCD by considering systematically all the lowest energy diquark\nchannels in a color gauge-invariant setup. We measure mass differences between\nthe various channels and show that the positive parity scalar diquark is the\nlightest. Quark-quark correlations inside the diquark are clearly seen in this\nchannel, and yield a diquark size of order 1 fm."
    }
]